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Biomedical subjects

G C Cook

Publications and source records attributed to G C Cook.

At least 127 records · Page 7Linked to original sources
PubMed1985

Infective gastroenteritis and its relationship to reduced gastric acidity.

Hypochlorhydria by compromising the defence mechanisms of the upper gastrointestinal tract predisposes to intestinal bacterial and parasitic infections. Achlorhydria predisposes to anaerobic colonization of the small intestine; colonization is far greater than in normal subjects even with partial neutralization of their gastric acidity after a meal. The best evidence for increased incidence of specific bacterial infection in the presence of achlorhydria relates to the nontyphoid salmonelloses. There is also strongly suggestive evidence in cholera. Among parasitic infections, the most impressive evidence relates to giardiasis and strongyloidiasis. In some instances, the infections themselves may also cause hypochlorhydria. Longitudinal studies are required. Whether patients receiving H2-receptor antagonists are unduly vulnerable to gastrointestinal infections is unclear. The importance of hypochlorhydria in 'Third World' populations, in whom gastrointestinal infections are extremely common, especially in infancy, is, at present, also impossible to evaluate.

Achlorhydria↗
PubMed1984

Aetiology and pathogenesis of postinfective tropical malabsorption (tropical sprue).

Postinfective tropical malabsorption (TM; tropical sprue) starts with an acute intestinal infection (bacterial, viral, or parasitic) which can affect predominantly the small or the large intestine. Miscellaneous invasive pathogens cause subsequent enterocyte damage affecting the entire small intestine and, to a lesser extent, the colon. Enteroglucagon, a tropic hormone, is then liberated and reaches a high plasma concentration. Small-intestinal stasis results. Further bacterial colonisation (in the lumen and also at the enterocyte surface) is encouraged. Continuing enterocyte damage is worsened by coexistent folate depletion, which is initiated at the onset of disease; body stores of folate reach a low concentration by 3 or 4 months. The cycle continues until the bacterial overgrowth is eliminated with an antibiotic (eg, tetracycline), or mucosal integrity recovers (hastened by oral folic-acid supplements), or both.

Chronic Disease↗
PubMed1982

Hepatic structure and function in Papua New Guineans with leprosy.

Hepatic function, including plasma bromsulphthalein (BSP) clearance was studied in 20 Papua New Guineans with leprosy: 11 lepromatous (LL) (6 had erythema nodosum leprosum (ENL)) (group A), and 9 tuberculoid or borderline (BT or BB) (group B); 12 controls (group C) were also studied. Four of five with abnormal BSP results had significant complicating or additional factors (hepatic amyloidosis, pustular ENL, hepato-cellular carcinoma and a pyogenic abscess), compared with two of 15 with normal results (tuberculous osteitis and pyogenic osteomyelitis). In nine (five from group A, and four from group B) needle liver biopsy histology was assessed: foci of vacuolated phagocytes and histiocytes, and tuberculoid granulomata were the most frequent lesions; none had cirrhosis. Leprosy is not associated with impaired hepatocellular function unless a severe complication or coincident disease is concurrently present. In this limited study therapeutic agents were not associated with abnormal liver structure or function. When liver function is abnormal in leprosy, another cause (e.g. secondary amyloidosis, sepsis or malignancy) should be searched for.

Adolescent↗
PubMed1982

Xylose absorption in Papua New Guineans with leprosy.

Blood xylose concentrations were measured at 60, 90 and 120 min after 25 xylose was given orally in 33 well-nourished Papua New Guinean in-patients at Port Moresby; 12 had lepromatous (group A) and seven non-lepromatous (group B) leprosy, and 14 were controls (group C). Differences between mean xylose concentrations were not significant at any time interval. Three patients (two in group A and one in group B) had 90 min xylose concentrations less than 2.0 mmol l-1. There was no association between xylose concentration and current therapy. Leprosy does not impair small-intestinal absorptive function; it therefore differs from other chronic infections, in which there is xylose malabsorption.

Adolescent↗
PubMed1981

Jejunal absorption rates of glucose and glycine in post-infective tropical malabsorption.

In a prospective study jejunal absorption rates of glucose (from a 200 mmol 1-1 solution) and glycine (from a 100 mmol 1-1 solution) were measured, using a perfusion technique, in nine patients with clinical evidence of post-infective tropical malabsorption (TM group) and in 10 others with trivial symptoms who had also visited the tropics (control group); all were of northern European origin. Seven and one in the two groups, respectively, had Giardia lamblia infections. Mean glucose absorption rate was significantly impaired by TM (P less than 0.01); mean rate for glycine was also depressed but not significantly. Presence of G. lamblia did not affect the severity of malabsorption although numbers studied were small.

Adult↗
PubMed1981

Influence of systemic infections on xylose absorption.

Serial blood-xylose concentrations have been determined in 28 Papua New Guineans after 25 g oral xylose; 9 had an acute and 8 a chronic systemic infection, 4 the tropical splenomegaly syndrome and 7 were free of infection. Mean xylose was significantly depressed at 30, 60, 90 and 120 min in those with acute and chronic infections. Correlations between xylose and serum albumin, alpha 1, alpha 2, beta- and gamma-globulin concentrations were not significant. When the xylose test is used in tropical countries the effect of systemic infections on the result must be careful evaluated, otherwise tropical malabsorption ('tropical sprue') might be diagnosed erroneously.

Administration, Oral↗
PubMed1980

The intestinal lactase polymorphism in Papua New Guinea.

Discovery of small numbers of people with the gene for persistence of intestinal lactase into adult life (PL) in several parts of Papua New Guinea (PNG) suggests that sporadic mutation as well as diffusion could account for at least part of its present distribution. The existing hypotheses attempting to account for at least part of its present distribution. The existing hypotheses attempting to account for the distribution of the gene have been applied to the available evidence in PNG populations. The water absorption and linkage disequilibrium hypotheses are possible explanations for selection of the trait; the culture historical and calcium absorption hypotheses seem unlikely, however, to explain the observed frequencies. It seems possible that more intensive study of the properties of the enzyme might reveal a connection with processes other than lactose hydrolysis.

Alleles↗
PubMed1980

Defect in plasma clearance of bromsulphthalein in Papua New Guineans with systemic infections.

One hundred and one Papua New Guineans, most of whom had systemic infections, received 5 mg kg body-weight-1 bromsulphthalein (BSP) intravenously after an overnight fast; serial venous blood BSP concentrations were measured for up to 2 hours. Many of those with infections had a reduction in plasma BSP disappearance rate and 30-minute retention. However, 15 per cent of 86 with infection had a secondary rise in plasma BSP concentration after 30 minutes, and in those followed serially a secondary peak was observed; that returned to normal after treatment and was not seen in 12 who were free of infection. Liver-biopsy specimens taken from four who had that defect in clearance did ot show Dubin-Johnson pigment. BSP curves with an exactly similar secondary rise after 30 minutes have previously been considered specific for the Dubin-Johnson syndrome, which is probably inherited as a Mendelian recessive; it seems possible that in the present study systemic infections have exposed the forme fruste of the condition. The present finding might explain some cases of jaundice associated with systemic infection commonly seen in Papua New Guinea. It might explain some toxic therapeutic reactions, because plasma concentrations of agents excreted in bile are likely to be abnormally elevated. If this abnormality in excretion proves to have a genetic basis it might prove valuable in mapping gene dispersal in South-east Asia and the Pacific.

Adolescent↗
PubMed1979

Gut hormones in tropical malabsorption.

Concentrations of various gut hormones were measured after a test breakfast in eight patients with severe tropical malabsorption and 12 controls. The patients with tropical malabsorption had greatly raised basal plasma motilin and enteroglucagon concentrations, but their postprandial release of both gastric inhibitory polypeptide and insulin was significantly reduced. The pattern of gut hormone release differed from that found in coeliac disease. The measurement of gut hormones, each of which has a specific site and function, thus throws new light on the pathophysiology of tropical malabsorption and may suggest approaches of treatment.

Adult↗
PubMed1979

Training of doctors and delivery of health care in developing countries.

In the past two decades, the training of doctors in developing countries has become confused with the delivery of health care. There should be a balance in the financial aid directed to rural and to urban areas; at present rural areas receive too much. The urban hospital, and especially the national teaching hospital, where most of the teaching, care of the seriously sick, and research are done, is in decline. In the training of doctors, the vital clinical approach, oriented towards the individual patient, is losing ground.

Curriculum↗