By R. Hamlar. State University of New York College of Agriculture and Technology, Cobleskill. 2019.
Managing population aging also requires building needed infrastructure and institutions as soon as possible order 25mg persantine otc. The longer we delay purchase 100mg persantine with visa, the more costly and less effective the solutions are likely to be purchase 25 mg persantine otc. We are only just beginning to comprehend its impacts at the national and global levels. As we prepare for a new demographic reality, we hope this report raises awareness not only about the critical link between global health and aging, but also about the importance of rigorous and coordinated research to close gaps in our knowledge and the need for action based on evidence-based policies. Since the beginning of recorded parasitic diseases that most often claimed history, young children have outnumbered the lives of infants and children. A World Health Organization expectancy over the past century were part analysis in 23 low- and middle-income countries of a shift in the leading causes of disease estimated the economic losses from three and death. At the dawn of the 20th century, noncommunicable diseases (heart disease, Figure 1. Young Children and Older People as a Percentage of Global Population: 1950-2050 Source: United Nations. The limits to life expectancy and and health conditions is one key to holding lifespan are not as obvious as once thought. The health And there is mounting evidence from cross- and economic burden of disability also can national data that—with appropriate policies be reinforced or alleviated by environmental and programs—people can remain healthy characteristics that can determine whether and independent well into old age and can an older person can remain independent continue to contribute to their communities despite physical limitations. Prevalence of dementia rises and ill health in developing countries will be sharply with age. An estimated 25-30 percent entering old age in coming decades, potentially of people aged 85 or older have dementia. Aging is taking place alongside other broad social trends that will affect the lives of older people. Economies are globalizing, people are more likely to live in cities, and technology is evolving rapidly. Demographic and family changes mean there will be fewer older people with families to care for them. People today have fewer children, are less likely to be married, and are less likely to live with older generations. By 2050, this number is expected to fell with surprising speed in many less developed nearly triple to about 1. Between 2010 and 2050, the number of older Most developed nations have had decades to people in less developed countries is projected to adjust to their changing age structures. In contrast, many less This remarkable phenomenon is being driven developed countries are experiencing a rapid by declines in fertility and improvements in increase in the number and percentage of older longevity. With fewer children entering the people, often within a single generation (Figure population and people living longer, older 2). For example, the same demographic aging people are making up an increasing share of the that unfolded over more than a century in total population. The Speed of Population Aging Time required or expected for percentage of population aged 65 and over to rise from 7 percent to 14 percent Source: Kinsella K, He W. In some countries, the sheer number of people entering older ages will challenge national infrastructures, particularly health systems. By the middle of this century, there could be 100 million Chinese over the age of 80. This is an amazing achievement considering that there were fewer than 14 million people this age on the entire planet just a century ago. Growth of the Population Aged 65 and Older in India and China: 2010-2050 Source: United Nations. Humanity’s Aging 5 Living Longer The dramatic increase in average life expectancy pathways. Less developed to noncommunicable diseases and chronic regions of the world have experienced a steady conditions. Even These improvements are part of a major earlier, better living standards, especially transition in human health spreading around more nutritious diets and cleaner drinking the globe at different rates and along different water, began to reduce serious infections and prevent deaths among children. Research for more recent periods shows a surprising and continuing improvement in life expectancy among those aged 80 or above. The progressive increase in survival in these oldest age groups was not anticipated by demographers, and it raises questions about how high the average life expectancy can realistically rise and about the potential length of the human lifespan. While some experts assume that life expectancy must be approaching an upper limit, 6 Global Health and Aging Figure 4. Living Longer 7 data on life expectancies between 1840 and 2007 global level, the 85-and-over population is show a steady increase averaging about three projected to increase 351 percent between 2010 months of life per year. The country with the and 2050, compared to a 188 percent increase for highest average life expectancy has varied over the population aged 65 or older and a 22 percent time (Figure 4). So far there is little evidence that life to increase 10-fold between 2010 and 2050. In many decreases in mortality rates among the oldest countries, the oldest old are now the fastest old. Percentage Change in the World’s Population by Age: 2010-2050 Source: United Nations, World Population Prospects: The 2010 Revision. Demographers and epidemiologists describe this Evidence from the multicountry Global Burden shift as part of an “epidemiologic transition” of Disease project and other international characterized by the waning of infectious and epidemiologic research shows that health acute diseases and the emerging importance of problems associated with wealthy and aged chronic and degenerative diseases. High death populations affect a wide and expanding rates from infectious diseases are commonly swath of world population. Over the next associated with the poverty, poor diets, and 10 to 15 years, people in every world region limited infrastructure found in developing will suffer more death and disability from countries. Although many developing countries such noncommunicable diseases as heart still experience high child mortality from disease, cancer, and diabetes than from infectious and parasitic diseases, one of the Figure 6. The Increasing Burden of Chronic Noncommunicable Diseases: 2008 and 2030 Source: World Health Organization, Projections of Mortality and Burden of Disease, 2004-2030. In direct bearing on the development of risk factors for 2008, noncommunicable diseases accounted for an adult diseases—especially cardiovascular diseases. Among the impairments or physical limitations at ages 80 or 60-and-over population, noncommunicable diseases older. Proving links between childhood health conditions But the continuing health threats from and adult development and health is a complicated communicable diseases for older people cannot research challenge. Older people account for a necessary to separate the health effects of changes growing share of the infectious disease burden in in living standards or environmental conditions low-income countries.
Urinary tract obstruction r Acute obstruction is almost always associated with Deﬁnition pain cheap 25mg persantine with amex, but chronic progressive obstruction usually Obstruction of the urinary tract at any level safe persantine 100 mg, whether causes dilatation with little or no pain 25 mg persantine amex. Clinical features Renal obstruction should be considered as a diagnosis Aetiology in all presentations of renal failure, as it is often asymp- The likely causes depend on the age of the patient and tomatic. High intake of ﬂuids may such as urethral valves or stenosis is most likely, whereas exacerbate the pain. Urine should be sent for microscopy and culture, ur- gently if infection is suspected. Complications Infection above the level of obstruction can cause Management pyelonephritis (pyonephrosis is the term for an infected, It is important to diagnose and treat urinary tract ob- obstructed hydronephrosis) or cystitis, and patients can struction quickly, as delayed treatment can cause irre- become very unwell due to pain, fever and sepsis. Therefore, if there is doubt, one of the ing is needed, to avoid hypotension or prerenal failure following may be required: during this phase. This is very useful, par- ticularlyinacuteobstructionbeforethereisdilatation, Pelviureteric junction obstruction as it shows contrast ‘held up’ by the obstruction and (idiopathic hydronephrosis) may show the lesion as a space-ﬁlling defect such as a radio-lucent stone or a papilla. Aetiology/pathophysiology r As part of the management percutaneous nephros- The cause is unknown. The mechanism of development of which may be exacerbated by drinking large amounts ‘myeloma kidney’ is via a direct toxic effect on re- of ﬂuid, for example it may become symptomatic for nal tubular cells and blockage of the tubules and col- the ﬁrst time in students who drink large quantities of lecting ducts by the paraprotein. Occasionallythe may develop amyloidosis and renal tubular acidosis as hydronephrosis is so marked that it can mimic ascites. In some cases, it is asymptomatic and diagnosed in- r Amyloidosis: This condition may be systemic or con- cidentally when an ultrasound is performed for another ﬁned to the kidneys and is an important cause of reason. Itcancauseproteinuria,nephrotic trasound scan, or in childhood during investigation of syndrome and renal failure. There is delayed passage of glomerulonephritis from minimal change disease, to contrast, which is not overcome by administration of membranous nephropathy, to proliferative glomeru- diuretics. Early treatment with immunosup- pression regimes such as plasmapheresis, high dose Prognosis steroids and cyclophosphamide can improve renal It is not possible to predict how much function will re- function. Thrombotic thrombocytopenic purpura – haemolytic uraemic The kidney in sytemic disease syndrome r Hypertension: See page 73. Often both ends of the spectrum are Chapter 6: Disorders of the kidney 259 present in the same patient. This causes a focal segmen- toxin (also called Shiga toxin) produced by Escherichia tal glomerulonephritis. Some This has markedly improved with the advent of plasma develop proteinuria later in life due to progressive exchange. Chronic renal failure occurs in a substantial glomerulosclerosis, occasionally leading to renal fail- number of patients. However, the prognosis for these patients is ex- cellent with no reduction in life expectancy. Congenital disorders of the kidney Renal hypoplasia r Simple renal hypoplasia is when the kidney is smaller Congenital malformations of the than normal, but the structure and histology of the kidney kidney is normal, although the nephrons may be Deﬁnition slightly small. Congenital malformations of the kidney are not uncom- r Oligonephronic renal hypoplasia (also called oligo- monly found on antenatal screening and in newborns. The prog- and the risk is higher in those with a previous family nosis is poor for these patients, although there may history. Chromosomal abnormalities account for a pro- be some initial improvement in renal function over portion, but most are sporadic. The fetal kidneys develop when the ureteric bud comes into contact with the metanephric blastema caudally Dysplasia (failure of differentiation) (in the ‘pelvic’ area), signalling it to form nephrons The kidney develops abnormally with primitive tubules and the collecting system. By 14–16 weeks, most r Horseshoe kidney – the kidneys remain fused at of the amniotic ﬂuid consists of fetal urine. Then the the upper (10%) or lower (90%) poles to form a kidneys have to migrate rostrally, to lie in the lumbar horseshoe-shapedstructure. These anatomical abnormalities may be symptomless, r Bilateral agenesis is rare and incompatible with life. About 50% tive uropathy and predisposition to urinary stones and Chapter 6: Disorders of the bladder and prostate 261 infections. In pregnancy, low pelvic kidneys can interfere Disorders of the bladder with labour. Age r Atresia: Failure of the ureteric bud to canalise, associ- Increases with age ated with renal dysplasia. An ectopic M > F ureter often arises from a duplex kidney, which may be associated with vesicoureteric reﬂux. The causes of bladder outﬂow obstruction are shown in Surgical re-implantation of the ureter may be indi- Table 6. Overtime,theblad- Benign prostatic hyperplasia der distends, then the ureters (causing hydroureters) and Deﬁnition ﬁnally the renal pelvises. Often there may be an un- Hyperplasiaoftheprostateisacommoncauseof bladder derlying chronic obstruction for example an enlarged outﬂow obstruction. Clinical features The symptoms depend on the speed of onset and degree Age of obstruction. Acute obstruction (acute urinary retention) causes se- vere discomfort, due to a wish to void urine, without Sex the ability to do so. There is complete anuria, although there may be small amounts of urine voided due to overﬂow in- Aetiology continence. However, polyuria and/or nocturia may Pathophysiology be symptoms of the loss of concentrating ability of the Androgens appear to act on the periurethral area of the tubules, which can occur in long-standing obstruc- prostate ‘McNeal’s transition zone’ to stimulate hyper- tion. At 30–40 years there is microscopic evidence, by 50 years it Macroscopy is macroscopically visible, by 60 years the clinical phase Dilation above the obstruction. The obstruction is due to both direct impingement Complications of the enlarged prostate on the urethra and also the dy- As aresultofchronicobstruction,thebladderdilatesand namic smooth muscle contraction of the prostate, pro- fails to empty fully, deﬁned as >50 mL residual urine static capsule and bladder neck. Nodules Management formedofhyperplasticglandularacinidisplaceandcom- Relief of the obstruction is usually by insertion of a uri- press the true prostatic glands peripherally forming a nary catheter, followed by treatment of the underlying false capsule. Chapter 6: Disorders of the bladder and prostate 263 Microscopy symptoms than α-blockers. It seems to be more effec- Benign epithelial proliferation with large acini, smooth tive in those with very large prostates and its effects muscleandﬁbroblastproliferation. The procedure involves removal Complications of prostatic tissue using electrocautery via a resecto- Bladder decompensation – due to chronically increased scope from within the prostatic urethra, under general residualvolumes(urineretainedaftervoiding),theblad- or spinal anaethesia. Post-operatively patients require der may become less contractile, lowering ﬂow rates fur- a three-way catheter and continuous bladder irrigation ther. Obstruction may lead to dilated ureters and kid- to reduce the risk of clot retention until haematuria is ney(hydroureter,andhydronephrosis).
Older patients Aetiology and those with suspicious features should undergo en- The transmission of H discount persantine 25mg free shipping. It produces an enzyme that breaks ing this treatment a further endoscopy is not neces- down the glycoproteins within the mucus cheap 25mg persantine amex. If symptoms persist or recur (or in all patients changes in the secretory patterns within the stomach initially presenting with complications) a urea breath along with toxin-mediated tissue damage order persantine 100mg on-line. Initial infec- test should be performed at 4 weeks and further erad- tion causes an acute gastritis which rapidly proceeds to ication therapy used if positive. Chapter 4: Disorders of the small bowel 163 Clinical features Aetiology/pathophysiology Most people become colonised by H. The excess acid causesinactivationofduodenal/jejunallipasesandhence Investigations steatorrhoea also occurs. Management Noninvasive tests can be performed if an endoscopy is Resection of the gastrinoma should be attempted but not indicated. High-dose proton pump belled urea, if the bacteria is present the urea is broken inhibitors are also used. Other treatment options in- down releasing labelled carbon dioxide which is de- clude octreotide, interferon α,chemotherapy and hep- tected in the breath. In inoperable tumours 60% of patients survive 5 years r Serological testing is simple, non-invasive and widely and 40% survive 10 years. Disorders of the small bowel Management and appendix First line eradication (triple) therapy consists of a pro- ton pump inhibitor, amoxycillin or metronidazole, and clarithromycin for 1 week. Second line (quadruple) ther- Acute appendicitis apy is with a proton pump inhibitor, bismuth subcitrate, Deﬁnition metronidazole and tetracycline. Compliance with treat- Inﬂammatory disease of the appendix, which may result mentisveryimportantforsuccessfultreatment. Incidence Commonest cause of emergency surgery of childhood Zollinger–Ellinson syndrome (3–4 per 1000). Deﬁnition Pathological secretion of gastrin resulting in hypersecre- Age tion of acid. Ultrasound is in- Aetiology/pathophysiology creasingly being used but does not exclude the diagnosis. Accumula- Conservative treatment has little place, except in patients tion of secretions result in distension, mucosal necrosis unﬁt for surgery. Fluid resuscitation may be required and invasion of the wall by commensal bacteria. Inﬂam- prior to surgery and intravenous antibiotics are com- mationandimpairmentofbloodsupplyleadtogangrene menced. Once perforation has occurred there is r Under general anaesthetic the abdomen is opened migration of the bacteria into the peritoneum (peritoni- by an incision along the skin crease passing through tis). Theoutcomedependsontheabilityoftheomentum McBurney’s point (one third of the distance from a and surrounding organs to contain the infection. The muscle ﬁbres in each muscle layer Clinical features are then split in the line of their ﬁbres (grid iron in- This is a classic cause of an acute abdomen. The mesoappendix is divided with ligation of tially periumbilical, then migrates to the right iliac fossa. The appendix is ligated at its There is mild to moderate fever, nausea and anorexia. The wound is then ment of the disease may be over hours to days partly closed in layers. In most cases, the appendix is tally particularly if the omentum is wrapped around the removed to avoid confusion if patients ever re-present appendix, or an abscess has formed. Macroscopy Prognosis The appendix appears swollen and the surface vascula- Uncomplicated appendicitis has an overall mortality of ture is yellow. Microscopy Meckel’s diverticulum Initially there is acute inﬂammation of the mucosa, which undergoes ulceration. As the condition progresses the inﬂammation An ileal diverticulum occurring as a result of persistence spreads through the wall until it reaches the serosal sur- of part of the vitellointestinal duct. Chapter 4: Disorders of the small bowel 165 Incidence due to ulceration of the adjacent ileum. Age Investigations Congenital Presence of gastric mucosa can be detected by scintiscan- ning with 99mTc labelled sodium pertechnetate, which is Sex taken up by parietal cells (the Meckel’s scan). Persistence of the Malabsorption syndromes ductmayresultinaMeckel’sdiverticulum(persistenceof Absorption of food occurs within the small bowel. The the ileal end of the duct), an umbilical sinus (persistence process involves breakdown of macromolecules by en- of the umbilical end of the duct) or an umbilical ileal zymes and transport across the specialised small bowel ﬁstula (see Fig. The most common causes of Pathophysiology malabsorption are pancreatic insufﬁciency, coeliac dis- The diverticulum arises from the antimesenteric border ease, resection of the ileum, Crohn’s disease and liver of the ileum 2 ft from the ileocaecal valve and is on aver- disease (see Fig. Acid secreting gastric mucosa is found in 50% of cases which may result in Coeliac disease ulceration of the surrounding mucosa. Clinical features Ninety-ﬁve per cent of cases are asymptomatic, symp- Incidence tomatic patients present most commonly with bleeding 1in2000. There is lymphocytic inﬁltration of the lamina propria, and an increase in intra-epithelial lymphocytes (which Geography bear the γδ eceptor). Loss of normal villous architecture Common in Europe, (1 in 300 in Ireland) rare in Black ranges from blunting (partial villous atrophy) to com- Africans. Aetiology Investigations Thought to be an autoimmune disease with genetic and r Serology: Screening by IgG gliadin and IgG anti- environmental components. Management Clinical features Aglutenfree diet leads to a restoration of normal villous Patients may present with irritability and failure to thrive structure and resolution of dermatitis herpetiformis (see in childhood, delayed puberty, short stature, or vomit- page 394). Haemoglobin and antiendomysial antibodies ing, diarrhoea, anorexia or abdominal distension at any may be checked at routine follow-up to look for inad- age. Complications Whipple’s disease There is an association with development of small bowel lymphomaandasmallincreasedriskinthedevelopment Deﬁnition of small bowel adenocarcinoma. Chapter 4: Inﬂammatory bowel disease 167 Aetiology Disorders of the large bowel Caused by an infection by Tropheryma whippelii,anacti- and inﬂammatory bowel nomycete. Diverticular disease Clinical features Patients present with steatorrhoea, abdominal pain and Deﬁnition systemicsymptomsoffever,weightloss,lymphadenopa- Adiverticulum is a mucosal out-pouching, diverticular thy and arthritis. Investigations and management Incidence Electron microscopy can demonstrate the organism. Tropical sprue Deﬁnition Aetiology AseveremalabsorptionsyndromeendemicinAsia,some Diverticulae are associated with high intraluminal pres- Caribbean islands and parts of South America. There is a relationship with a low ﬁbre diet and Aetiology/pathophysiology chronic constipation.
If the post-test probability of a bleed is high buy persantine 100 mg without prescription, standard treatment is likely to be better generic persantine 25mg on line, since thrombolytic therapy is more likely to lead to increased bleeding in the brain generic persantine 100 mg without a prescription. An exam- ple would be a person with known atrial ﬁbrillation, not on anticoagulants, who had a sudden onset of severe left hemiparesis without a headache. Changing one fact of this pattern would change the probability of a bleed and the ﬁnal decision. At a high pretest probability the clinical picture is so strong that the test shouldn’t be done at all since a false negative is much more likely than a true negative leading to treatment of someone with a potential bleed. An example would be someone with a sudden onset of the worst headache of their life with their only deﬁcit being slight weakness of their non-dominant hand. Here the potential of giving thrombolytic therapy to someone with a bleed is too high and the projected beneﬁt not great enough. Mathematical expression of threshold approach to testing There are formulas for calculating these thresholds, but please don’t memorize them. A false positive test resulting in unnecessary use of risky tests or treatments such as cardiac catheterization or cardiac drugs or a false negative test resulting in unnecessarily withholding beneﬁcial tests or treatments are both adverse out- comes of testing. You can substitute different values of test characteristics, dif- ferent positive and negative predictive values, and different values of the beneﬁt and risk of treatment in a sensitivity analysis of the decision tree and determine what the effect of these changes will be on the utility of each treatment arm. Markov models Another method of making a decision analysis is through the use of Markov mod- els. The difﬁculty with these is that there must be some data on the average time a given individual patient spends in each health state. Ovals are states of health associated with quality measures such as death (U = 0), complete health or cure (U = 1), and other outcomes (U varies from 0 to 1). Arrows are transitions between states or within a state and are attached to probabilities or the likelihood of changing states or remaining in the same state. This type of model is ideal for putting into a computer to get the ﬁnal expected values. Ethical issues Finally, there are signiﬁcant ethical issues raised by the use of decision trees and expected-values decision making. When there are limited resources, is it more just to spend a large amount 346 Essential Evidence-Based Medicine of resources for a small gain? Is a small gain deﬁned as one affecting only a few people or one having only a small health beneﬁt? Some of these questions can be answered using cost-effectiveness analyses and will be covered in the next chapter. The use of a decision tree in making medical decisions can help the patient, provider, and society decide which treatment modality will be most just. Look for treatments that beneﬁt the most people or have the largest overall improve- ment in health outcome. Ethical problems arise when a choice has to be made on whether to consider the best outcome from the perspective of a large popula- tion or the individual patient. If we take the perspective of the individual patient, how are we to know that the treatment will beneﬁt that particular patient, the next patient, or the next 20 patients? Is the decision up to each individual or should the decision be legislated by society? Decision trees allow the provider, society, and the patient to decide which ther- apy is going to be the most beneﬁcial for the most people. Whether decision trees are a mathematical expression of utilitarianism is a hotly debated issue among bioethicists. The basic perspectives of medical care within the tra- ditional patient–physician relationship include medical indications, which are physician-directed, and patient preferences, which are patient-driven. Current or added perspectives modify the decision and include quality of life, which considers the impact on the individual of high-technology interventions and contextual features, which are cultural, societal, family, religious or spiritual, community, and economic fac- tors. These are all part of the discussion between the provider and the patient and form the basis of the provider–patient relationship. Assessing patient values Patient values must be incorporated into medical decision making and health- care policies by providers, government, managed care organizations, and other decision makers. The output of decision trees is variable and ultimately is based on the patient preferences. We can measure and quantify patient values and use them in decision trees to help patients make difﬁcult decisions. Using unadjusted life expectancy or life years cannot compare various states of health in cases with the same number of years of life because they do not quantify the quality of those years. Quality-of-life scales or measures of status rated by others or by the patient themself include health status, functional sta- tus, well-being, or patient satisfaction. These Decision analysis and quantifying patient values 347 Table 30. This discussion will present sev- eral standardized quantitative measures of patient preference that can be used to measure the relative preference that a patient has for one or another outcome. The time trade-off method for this example asks “suppose you have 10 years left to live with chronic residual neurological disability from the stroke. If you could trade those 10 years for x years without any residual neurological deﬁcit, what is the smallest number of years you would trade to be deﬁcit-free? The patient is told to consider an imaginary situa- tion in which you will give them a pill that will instantly cure their stroke. How- ever, there is a risk in that it occasionally causes instant but painless death. On the other hand, if there were 0% cure and 100% death no one would ever take the pill unless the patient is extremely depressed and considers their life totally worthless. Continue to change the cure-to-death ratio until the person cannot decide which course of action to take. Set up a “mini decision tree” and solve for the utility of living with chronic neurological deﬁcit. This is the value of living with a chronic stroke syndrome that the patient assigns as an outcome through a standard gamble. Different values will be obtained from each method used to measure patient values. The linear rating scale measures the quality of functionality of life, the time trade-off introduces a choice between two certainties, and the standard gamble introduces probability and willingness to take risks into the equation. Attitudes toward risk and framing effects Attitudes toward risk vary with individuals and at different periods of time during their lives.
Several doubly labeled water studies indicate a progres- sive increase in total energy expenditure over the 36 weeks of pregnancy (Forsum et al buy persantine 100mg free shipping. The mean difference in energy expenditure between week 0 and 36 in the studies was approximately 460 kcal/d and is proportional to body weight discount persantine 100mg free shipping. The fetus does not utilize significant amounts of free fatty acids (Rudolf and Sherwin discount 25mg persantine mastercard, 1983). As part of the adaptation to pregnancy, there is a decrease in maternal blood glucose concentration, a development of insulin resistance, and a tendency to develop ketosis (Burt and Davidson, 1974; Cousins et al. A higher mean respiratory quotient for both the basal metabolic rate and total 24-hour energy expenditure has also been reported in pregnant women when compared to the postpartum period. The increased glucose utilization rate persists after fasting, indicating an increased endogenous production rate as well (Assel et al. Thus, irrespective of whether there is an increase in total energy expenditure, these data indicate an increase in glucose utilization. Earlier, it was reported that the glucose turnover in the overnight fasted state based on maternal weight gain remains unchanged from that in the nonpregnant state (Cowett et al. The fetus reportedly uses approximately 8 ml O2/kg/min or 56 kcal/ kg/d (Sparks et al. The transfer of glucose from the mother to the fetus has been estimated to be 17 to 26 g/d in late gestation (Hay, 1994). If this is the case, then glucose can only account for approximately 51 percent of the total oxidizable substrate transferred to the fetus at this stage of gestation. The mean newborn infant brain weight is reported to be approximately 380 g (Dekaban and Sadowsky, 1978). Assuming the glucose consumption rate is the same for infants and adults (approximately 33 µmol/100 g of brain/min or 8. This is greater than the total amount of glucose transferred daily from the mother to the fetus. Data obtained in newborns indicate that glucose oxidation can only account for approximately 70 percent of the brain’s estimated fuel require- ment (Denne and Kalhan, 1986). In addition, an increase in circulating ketoacids is common in pregnant women (Homko et al. Taken together, these data suggest that ketoacids may be utilized by the fetal brain in utero. If nonglucose sources (largely ketoacids) supply 30 percent of the fuel requirement of the fetal brain, then the brain glucose utilization rate would be 23 g/d (32. These data also indicate that the fetal brain utilizes essentially all of the glucose derived from the mother. There is no evidence to indicate that a certain portion of the carbohydrate must be consumed as starch or sugars. The lactose content of human milk is approximately 74 g/L; this concentration changes very little during the nursing period. Therefore, the amount of precursors necessary for lactose synthesis must increase. Lactose is synthe- sized from glucose and as a consequence, an increased supply of glucose must be obtained from ingested carbohydrate or from an increased supply of amino acids in order to prevent utilization of the lactating woman’s endogenous proteins. However, the amount of fat that can be oxidized daily greatly limits the contribution of glycerol to glucose production and thus lactose formation. For extended periods of power output exceeding this level, the dependence on carbohydrate as a fuel increases rapidly to near total dependence (Miller and Wolfe, 1999). Therefore, for such individuals there must be a corre- sponding increase in carbohydrate derived directly from carbohydrate- containing foods. Additional consumption of dietary protein may assist in meeting the need through gluconeogenesis, but it is unlikely to be con- sumed in amounts necessary to meet the individual’s need. A requirement for such individuals cannot be determined since the requirement for carbohydrate will depend on the particular energy expenditure for some defined period of time (Brooks and Mercier, 1994). They are composed of various proportions of glucose (dextrose), maltose, trisaccharides, and higher molecular-weight products including some starch itself. These syrups are also derived from cornstarch through the conversion of a portion of the glucose present in starch into fructose. Other sources of sugars include malt syrup, comprised largely of sucrose; honey, which resembles sucrose in its composition but is composed of individual glucose and fruc- tose molecules; and molasses, a by-product of table sugar production. With the introduction of high fructose corn sweeteners in 1967, the amount of “free” fructose in the diet of Americans has increased consider- ably (Hallfrisch, 1990). Department of Agriculture food consumption survey data, nondiet soft drinks were the leading source of added sugars in Americans’ diets, accounting for one-third of added sugars intake (Guthrie and Morton, 2000). This was followed by sugars and sweets (16 percent), sweetened grains (13 percent), fruit ades/drinks (10 percent), sweetened dairy (9 percent), and breakfast cereals and other grains (10 percent). Together, these foods and beverages accounted for 90 percent of Ameri- cans’ added sugars intake. Gibney and colleagues (1995) reported that dairy foods contributed 31 percent of the total sugar intakes in children, and fruits contributed 17 percent of the sugars for all ages. The majority of carbohydrate occurs as starch in corn, tapioca, flour, cereals, popcorn, pasta, rice, potatoes, and crackers. Between 10 and 25 percent of adults consumed less than 45 percent of energy from carbohydrate. Less than 5 percent of adults consumed more than 65 percent of energy from carbohydrate (Appendix Table E-3). Median carbohydrate intakes of Canadian men and women during 1990 to 1997 ranged from approximately 47 to 50 percent of energy intake (Appendix Table F-2). More than 25 percent of men consumed less than 45 percent of energy from carbohydrate, whereas between 10 and 25 per- cent of women consumed below this level. Less than 5 percent of Canadian men and women consumed more than 65 percent of energy from carbo- hydrate. Data from the Third National Health and Nutrition Examination Survey shows that the median intake of added sugars widely ranged from 10 to 30 tsp/d for adults, which is equivalent to 40 to 120 g/d of sugars (1 tsp = 4 g of sugar) (Appendix Table D-1). Potential adverse effects from consuming a high carbohydrate diet, including sugars and starches, are discussed in detail in Chapter 11. Behavior The concept that sugars might adversely affect behavior was first reported by Shannon (1922).
However persantine 100mg low price, if samples must be held for more than a few days they should be frozen on the day of collection to minimise decomposition generic 100mg persantine otc. Chapter 2 100mg persantine visa, Field manual of wildlife diseases: general field procedures and diseases of birds. Where samples need to be chilled or frozen an understanding of the concept of the ‘cold-chain’ is required. This refers to the need for samples to remain at the desired temperature and not to experience cycles of change (e. The requirements for sample packaging and shipment vary between countries and diagnostic laboratories. It is, therefore, essential to contact the laboratory that will analyse samples to find out any specific shipping requirements as early as possible in the procedure. This will help with processing samples upon their arrival at the laboratory and reduce the risk of sample quality being compromised. Transporting and/or shipping samples must not pose a biosecurity or human health risk. Seek advice from veterinary authorities about safety and regulations for transporting and shipping samples. The most important considerations for successful sample transport and shipment are: prevent cross-contamination between specimens prevent decomposition of the specimen prevent leakage of fluids preserve individual identity of specimens properly label each specimen and the package in which they are sent. Prevent breakage and leakage Isolate individual specimens in their own containers and plastic bags. Protect samples from direct contact with coolants such as dry ice or freezer blocks. Ensure that if any sample breaks or leaks the liquid does not leak to the outside of the package by containing all materials inside plastic bags, or other leak-proof containers, where possible. Containing specimens The plastic bags for containing specimens need to be strong enough to resist being punctured by the materials they hold and those adjacent to them. Polystyrene boxes within cardboard boxes are useful for their insulating and shock absorbing properties. If polystyrene boxes are not available, sheets of this material can be cut to fit inside cardboard boxes with a similar effect (though the package is less leak-proof). The strength of the cardboard box needs to be sufficient for the weight of the package. If hard plastic or metal insulated boxes are used for transport, cardboard boxes around them can be used for protection and to attach labels. It is possible to make ice packs by freezing water inside a plastic bottle that is sealed (not filled completely and taped closed to prevent the top coming off in transit) and then placed in a sealed plastic bag to further prevent leakage. If frozen carcases are being transported they can act as a cool pack for other samples sent in the same container. When using ice packs they should be interspersed between samples to achieve a uniform temperature throughout. When submitting dead fish for post mortem examination they should be wrapped in moist paper to prevent them drying out and then refrigerated but not frozen. Fish decay very quickly but a fish refrigerated soon after death may be held for up to twelve hours before examination and sample fixation. Keeping samples frozen Dry ice (solid carbon dioxide) or in some circumstances liquid nitrogen can be used to ship frozen specimens. The gaseous carbon dioxide given off by dry ice can also damage some disease agents and this must be considered before using it for tissue transport. As the volume of both dry ice and liquid nitrogen expand as they change to gas, specialist containers that allow for this expansion are needed for their transportation. Note: Shipment of formalin, dry ice, liquid nitrogen and alcohol is regulated in many countries and must be cleared with a carrier before shipping. Samples preserved in formalin, other chemical fixative or alcohol can be transported without chilling. Shipping It is important to pack any space within packages with a substance such as newspaper which will prevent movement of containers, act as a shock absorber and may also soak up any potential leakages. Packaging and labelling Packaging and labelling of specimens must conform to the regulations of the country from which the package is sent and also those of the country in which it will be received (if it is being sent to a laboratory in another country). It is important to mark the outside of the package with the required labelling regarding the type of specimen being transferred and where necessary the method of cooling (e. Advice from national authorities about permit requirements must be sought prior to collection and transportation of samples. Carriers Samples should be shipped where possible by carriers that can guarantee 24-hour delivery to the diagnostic laboratory. Where possible arrange for collection of sample packages from the point of origin to avoid delays. When shipping arrangements have been made, contact the diagnostic laboratory to provide them with further details including estimated time of arrival and any shipping reference numbers. Chapter 3, Field manual of wildlife diseases: general field procedures and diseases of birds. Detailed field observations during the course of an outbreak and information about events preceding it, may provide valuable data on which to base a diagnosis and corrective actions. It is important for the information gatherer to keep an open mind about the potential cause of the problem. Some information which may seem irrelevant in the field may become very important when piecing together the events leading up to an outbreak. A thorough chronology of events is key to diagnosis and disease control operations, and is almost impossible to obtain some time after the outbreak has occurred. A key concept is that of explaining to the diagnostician how the affected individuals relate to the whole population at risk. As an example, 100% of the dead animals may be adult males but the population present (i. How to record data It is important to record as much relevant information as possible as soon as events unfold. Photographs and video footage can quickly convey specific information such as land use, landscape, environmental conditions, gross lesions and the appearance of clinical signs in sick animals.