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Biomedical subjects

R McLean

Publications and source records attributed to R McLean.

36 records · Page 2Linked to original sources
PubMed1977

Effect of iron saturation of transferrin on hepatic iron uptake: an in vitro study.

Studies were performed to delineate the effect of percentage of saturation of transferrin and total iron concentration on the rate of uptake of iron by the perfused rat liver. Normal and iron-deficient rat livers were perfused with sera that contained varying concentrations of 59Fe-labeled iron and transferrin saturation. Varying the percentage of saturation of transferrin while maintaining a constant concentration of iron did not influence the hepatic uptake of iron. However, raising the concentration of iron in the perfusate while maintaining a constant saturation of transferrin did increase the uptake of iron by the liver. At similar concentrations of iron and transferrin saturation, iron-deficient livers took up greater amounts of iron than did normal livers. In our experiments, the hepatic uptake of transferrin-bound iron is determined by (1) the concentration of iron in perfusate and (2) the status of iron stores in the liver being perfused.

Animals↗
PubMed1975

Amidines and related compounds. 6. Studies on structure-activity relationships of antihypertensive and antisecretory agents related to clonidine.

Correlations of antihypertensive and antisecretory activities with various structural modifications of the antihypertensive agent clonidine (2-(2,6-dichlorophenylimino)imidazolidine) are described. Eleven chemical classes of compounds containing an "amidine" moiety were prepared in this study. The antihypertensive activity of these compounds was evaluated in metacorticoid hypertensive rats and unanesthetized neurogenic hypertensive dogs following oral administration. Antisecretory activity was evaluated in fistula rats by measuring pH and volume of gastric secretion. Two compounds, 2-(2,6-dimethylphenylimino)imidazolidine and 2-(2,6-dichlorophenylimino)pyrrolidine, are particularly effective antisecretory agents with minimal antihypertensive activity.

Amidines↗
PubMed1975

The utilization of dental skills in non-dental situations.

The development of electronic control systems has enabled severely physically handicapped people to revolutionize their lives by using any minimal residual movements they may have to operate micro-switches linking them with typewriters and other environmetal controls. Technical skills of a high order are required in making the unique splint or interface which links the switches with these residual movements whether of the tongue, lips, chin, eyebrow, finger or toe. Through the initiative of the Cordent Trust and generous financial support from the Leverhulme Trust a mobile laboratory was designed and built and a dental technician appointed for a three-year development project in the use of these switches as it was felt that his experience was particularly appropriate to the work and would also demonstrate how dental skills can be used to bring about a degree of rehabilitation far beyond the oral environment.

Electronics, Medical↗
PubMed1973

C2 deficiency. Development of lupus erythematosus.

The study of serum from a patient with C2 deficiency is described. The patient had an episode of pneumococcal meningitis at 5 mo of age with seizures and transient hemiparesis and apparent purpuric skin lesions. He was first admitted to the University of Minnesota Hospitals at 10 yr of age following the discovery of proteinuria accidentally by his mother. Since then he has been admitted repeatedly to this hospital with numerous clinical findings including arthralgia, recurrent abdominal pain, proteinuria, membranous nephropathy, malar butterfly rash, seizures, personality aberrations, and recurrent fever. In June 1971, the patient developed positive DNA and DNP antibodies and positive LE cells. When the C profile was studied before and after recognition of lupus, C1q, C1s, and C4 dropped. C3 levels were elevated as were C5, C6, and C7, C3 proactivator had been reduced in the patient even before he developed lupus. Also because of a traumatic renal biopsy leading to a perirenal hematoma, he required surgery and a blood transfusion. 1 h after blood transfusion, a C2 titer of 23 hemolytic units was detected. Almost immediately levels of C3, C5, C6, and C7 dropped, C8 and C9 remained elevated. The addition of C2 from normal blood permitted dramatic activation of C3. These findings support the view that the rare deficiency in production of C2 predisposes to serious susceptibility to infection, vascular and mesenchymal disease as well as to renal disease and a lupus syndrome.

Antibodies↗
PubMed1973

The association of respiratory infection, recurrent hematuria, and focal glomerulonephritis with activation of the complement system in the cold.

The study of the activation of C3, C5, and C7 associated with the conversion of C3 in the serum of a 9-yr old girl after incubation at 0 degrees C for 6-8 h without utilization of C1, C4, and C2 is described. The patient has upper respiratory infections associated with recurrent gross hematuria, focal glomerulonephritis, and transient renal insufficiency. Histological lesions demonstrated the presence of B1c globulin IgA and properdin in the glomeruli. The activation of complement (C) in the cold requires the patient's IgA. Removal of IgA from the serum by immunoadsorption prevents activation and conversion of C3. Bactericidal and phagocytic activity is also impaired after incubation. C3 proactivator (C3PA) level is reduced before and after incubation. Properdin level drops after incubation. These findings suggest that the activation of C3 which is demonstrable in vitro may be a continuous process in vivo.

Child↗
PubMedDate not supplied

A new sterile bicarbonate dialysis solution for use during cardiopulmonary bypass.

Adding a dialysis filter to the perfusion circuit at the end of cardiopulmonary bypass (CPB) has become an accepted means of reducing potassium rapidly and safely. Rapid removal of solute requires a dialysate for diffusion, and peritoneal dialysis solutions have been the standard because of availability, although occasionally normal saline or bicarb/ saline mixtures are used. Cardioplegia solution is high in glucose as well as potassium and, with many diabetic patients undergoing CPB, it is desirable to minimize glucose loads. In this prospective cohort study, six patients received a commercially available sterile bicarbonate dialysate prepared in a point of care fashion. From the cardiovascular data base, four control patients (receiving lactate based dialysis solution during CPB) were matched for age, surgery type, body surface area (BSA), and pump duration for each of the six patients receiving bicarbonate dialysate. All of the control patients were dialysed against lactate buffered peritoneal dialysis solution. Plasma levels of potassium, glucose, and bicarb were measured before and after dialysis for each dialysate. Plasma potassium, glucose, and bicarb were not significantly different at start of dialysis. The lactate dialysate (LD) group received a mean of 17.4+/-7.7 L of lactate containing dialysate versus 14.6+/-4.7 L of bicarbonate dialysate (BD) (p = 0.41). After dialysis, potassium had been reduced to a similar degree in both groups, but plasma glucose levels had increased during LD while they fell during BD, and bicarbonate levels fell during LD while they rose during BD. Use of a commercially available sterile bicarbonate dialysate can safely help to lower plasma potassium during CPB and preserve more physiologic levels of glucose and bicarbonate.

Acidosis↗
PubMedDate not supplied

Crow deaths as a sentinel surveillance system for West Nile virus in the northeastern United States, 1999.

In addition to human encephalitis and meningitis cases, the West Nile (WN) virus outbreak in the summer and fall of 1999 in New York State resulted in bird deaths in New York, New Jersey, and Connecticut. From August to December 1999, 295 dead birds were laboratory-confirmed with WN virus infection; 262 (89%) were American Crows (Corvus brachyrhynchos). The New York State Department of Health received reports of 17,339 dead birds, including 5,697 (33%) crows; in Connecticut 1,040 dead crows were reported. Bird deaths were critical in identifying WN virus as the cause of the human outbreak and defining its geographic and temporal limits. If established before a WN virus outbreak, a surveillance system based on bird deaths may provide a sensitive method of detecting WN virus.

Animals↗