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C Ritchie

Publications and source records attributed to C Ritchie.

36 records · Page 2Linked to original sources
PubMed1990

The HLA genetic constitution of the Bushmen (San).

The HLA-A, -B, and -C antigens of 290 and the DR antigens of 212 !Kung San individuals were characterized. The most frequent antigens were HLA-A30 [gene frequency (gf) = 0.193], Bw58 (gf = 0.303), Cw6 (gf = 0.327), DR4 (gf = 0.273), and DQw3 (gf = 0.553). An unexpected finding was the low frequency of the classic African black antigen Bw42 (gf = 0.004). Marked differences as well as similarities in HLA gene frequencies were observed between the San and the South African Negroes, supporting the view that they had a common origin and were then separated for a very long time. During this period differences developed as a result of selective advantage in the Negroes following the pastoralist-agriculturalist way of life as opposed to the hunter-gatherer way of life. The picture is further complicated by the fact that gene flow, mostly from the San to the southern African Negroes, took place when they met again a few hundred years ago. The data also illustrate HLA haplotypes, linkage disequilibria, and four-locus haplotypes not previously seen in other human populations. The most frequent four-locus haplotype in the San, HLA-Aw43,Cw7,B7,DRw6 was also different from A30, Cw2,Bw42,DR3, the most common among the South African Negroes.

Africa, Southern↗
PubMed1988

The effect of hemodialysis on whole blood, plasma and erythrocyte viscosity.

The effect of hemodialysis (HD) on blood viscosity has not been adequately investigated. We studied blood viscosity during HD employing coneplate viscometry. Ten patients with end-stage renal disease were studied before and immediately after HD. To dissect the possible effects of HD on plasma and red blood cell (RBC) determinants, we measured whole blood, plasma, and reconstituted erythrocyte viscosities. The latter consisted of RBC's suspended in a buffered saline solution (pH = 7.4 units). In addition, serum, electrolytes and hematocrit (HCT) were measured. The results revealed a significant rise in whole blood viscosity after dialysis. Likewise, plasma viscosity rose considerably with dialysis. However, when the RBC's were reconstituted to a constant HCT, no significant difference was noted before and after HD. As expected, body weight, blood urea nitrogen (BUN) and creatinine concentrations fell while HCT and protein concentration rose with HD. A significant correlation was found between the observed rise in HCT, and dialysis-induced rise in whole blood viscosity. Likewise, the observed rises in plasma viscosity after dialysis significantly correlated with the rise in protein concentration. In addition, the change in whole blood and plasma viscosity values correlated with the degree of ultrafiltration (weight loss). In conclusion, whole blood and plasma viscosity rises with hemodialysis. The observed rise in viscosity is primarily due to hemoconcentration.

Acid-Base Equilibrium↗
PubMed1985

Genetic polymorphisms of apolipoprotein C-III and insulin in survivors of myocardial infarction.

Genetic polymorphisms of apolipoprotein C-III (apo C-III) and insulin were studied in 48 Caucasian post-myocardial infarction patients. 10 patients (21%) had an uncommon allelic variant of the apo A-I/C-III gene cluster (on the long arm of chromosome 11); in 47 control subjects this variant was present in only 2 and in none of those who were normotriglyceridaemic. Distribution of genotypes between post-infarct and normotriglyceridaemic control groups was significantly different and the difference persisted when the normotriglyceridaemic subgroups of these patients were compared. In contrast, there was no difference in distribution of alleles at the highly polymorphic locus on the short arm of chromosome 11 adjacent to the insulin gene.

Adult↗
PubMed1985

The measurement of high density lipoprotein subfractions in patients with primary gout using a simple precipitation method.

We have evaluated a simple dextran sulphate precipitation method for measuring high density lipoprotein cholesterol (HDL) subfractions and have used this method to measure plasma HDL2 and HDL3 in a group of 28 patients with primary gout. These patients were found to have significantly lower levels of plasma HDL and HDL2 than a group of healthy controls, matched for age and sex and of similar body mass index (BMI); no significant difference in mean levels of the HDL3 subfraction was found however. We have confirmed the high prevalence of hypertriglyceridaemia in subjects with gout compared to controls and the mean serum triglyceride levels were significantly higher (P less than 0.01) in the gout group than in controls. We have also shown that subjects with high serum triglyceride levels tend to have low plasma HDL2 concentrations, a finding which is consistent with an inverse relationship between these two parameters. These lipid abnormalities may partly explain the high prevalence of premature atherosclerosis in patients with primary gout.

Chemical Precipitation↗
PubMed1984

Transition from a hunter-gatherer to a settled lifestyle in the !Kung San: effect on iron, folate, and vitamin B12 nutrition.

In 1969 a group of hunter-gatherer San were studied (Am J Clin Nutr 1971;24:229-42). Their state of hematological nutrition was excellent with a negligible incidence of iron, folate, or vitamin B12 deficiency. A genetically and linguistically similar San community who have been settled for the past 15 yr were the subjects of the present study. Anemia, due in the main to iron and/or folate deficiency, has become more common. Alcoholism has become rife in both sexes and all age groups. Our findings show that a settled lifestyle has resulted in a significant deterioration in the San's hematological nutrition.

Adolescent↗
PubMed1982

Clostridium difficile-associated colitis: cross infection in predisposed patients with renal failure.

Four men with renal failure developed Clostridium difficile-associated diarrhoea while being cared for in the same ward at about the same time. Cross infection appeared to play a role. All patients had received antibiotics; three were treated for chest infections and one for a urinary tract infection. The antibiotics implicated were cefoxitin alone in two patients, cefoperazone alone in one patient and cloxacillin, cefoperazone and amoxycillin in the last patient. Two patients had received immunosuppressive agents as well. Clostridium difficile cytotoxin was detected in stools from all patients using a cell culture assay. Pseudomembranous colitis was demonstrated in two patients at sigmoidoscopy and in one at post mortem. All patient were given oral vancomycin. Two died with the disease, one following relapse in the absence of antibiotics, and two patients were cured only to die later of unrelated diseases. Isolation of affected patients seems prudent as the disease may be infectious.

Anti-Bacterial Agents↗
PubMedDate not supplied

Application of red cell distribution width to screening for coeliac disease in insulin-dependent diabetes mellitus.

Coeliac disease has been reported to occur in 2-5 per cent of insulin-dependent diabetic patients (IDDM). Suitable non-invasive screening tests would allow identification of these patients. The aim of this study was to determine the value of the red cell distribution width (RDW) in detecting unrecognised coeliac disease in insulin-dependent diabetic patients (IDDM). All patients (n = 208) attending the Diabetic out-patient clinics at 2 adjacent centres who had a full blood picture and RDW carried out in the past 18 months were included. IDDM patients with an elevated RDW were identified and their charts were reviewed to determine if they had symptoms or laboratory abnormalities compatible with coeliac disease. They were invited to attend for serological screening. Ninety-five of 208 patients had an elevated RDW of whom 66 had non-insulin dependent diabetes mellitus and 29 had IDDM. Two of the 29 IDDM patients had died in the interim period. Six of the remaining 27 IDDM patients had previously been tested for serological markers associated with coeliac disease, of whom 1 had a positive antigliadin antibody titre (IgA-AGA 199 EU) and normal duodenal biopsy. Eighteen of the remaining 21 patients with IDDM consented to serological testing of whom only 1 had a positive titre of antiendomysial antibody (IgA-EMA) and villous atrophy. Although the RDW is known from previous studies to be a sensitive predictor for coeliac disease, this study has demonstrated its poor specificity in predicting IDDM patients who may have coeliac disease. The RDW is not recommended as a screening test for coeliac disease in patients with IDDM.

Celiac Disease↗
PubMedDate not supplied

Effect of erythropoietin administration on blood and plasma viscosity in hemodialysis patients.

The effect of recombinant human erythropoietin (EPO) on whole blood and plasma viscosity was studied in six anemic hemodialysis (HD) patients, and five equally anemic placebo treated HD patients. Viscosity was determined pre- and postdialysis using cone-plate viscometry. Predialysis values for hematocrit and whole blood viscosity increased significantly over a 12 week period in the EPO but not the placebo treated group; plasma viscosity did not change in either group. Whole blood viscosity measured before and after a single HD session during week 12 revealed a significant rise. This change, expressed as a percent of the predialysis values, was similar in the two groups. Thus, the rise in whole blood viscosity seen in EPO treated patients is a result of the increase in erythrocyte concentration and not a result of an effect of EPO on plasma. In addition, EPO does not seem to alter the acute effect of HD on blood viscosity.

Adult↗
PubMedDate not supplied

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Activities of Daily Living↗