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Biomedical subjects

J McDonald

Publications and source records attributed to J McDonald.

At least 181 records · Page 10Linked to original sources
PubMed1986

Insemination with fresh donor semen.

Factors influencing the probability of conception after artificial insemination with donor semen were investigated in a series of 80 infertile couples. Overall, 46 pregnancies were achieved for a crude pregnancy rate of 58%. Life table analysis showed a cumulative probability of conception of 97.1% at the end of 12 cycles and an average fecundability of 15.1%. These results were achieved using a single insemination per cycle and individualizing the day of insemination based on the woman's basal body temperature. Women who had been pregnant previously had a significantly better fecundability than nulligravid women (P less than .05). The overall rates of conception in those women who required therapy for ovulatory dysfunction were the same as normal women although the fecundability was somewhat lower. Women who had abdominal pathology had an overall conception rate of 23%.

Cervix Mucus↗
PubMed1985

Macronutrients have different metabolic effects in nondiabetics and diabetics.

The glycemic and hormonal responses to protein, fat and carbohydrate alone and together were studied in normal, noninsulin-dependent (NIDD) and insulin-dependent (IDD) diabetic subjects. Fat and protein markedly reduced the glycemic response to oral carbohydrate in nondiabetics. In NIDD, the presence of protein and fat had no significant effect on the glycemic response. In IDD, while fat had no effect, protein enhanced the glycemic response. The insulin and GIP responses to the macronutrients together and individually were remarkably similar in all subject groups. Protein behaved as an insulin secretagogue in normal and NIDD while fat acted as a GIP secretagogue in normal and both diabetic groups. Protein appeared to function as a GIP secretagogue when combined with both fat and carbohydrate. It is concluded that caution is required when the glycemic responses to foods observed in nondiabetics are extended to diabetics.

Adult↗
PubMed1985

Food physical factors have different metabolic effects in nondiabetics and diabetics.

Physical properties of food may account for differences in glycemic and other metabolic responses to food with similar amounts of carbohydrate, fat and protein. Blending of cooked beans made no difference to plasma glucose, insulin, or GIP (gastric inhibitory polypeptide) responses in nondiabetics, NIDD (noninsulin-dependent diabetics), and IDD (insulin-dependent diabetics). The cooked blended beans gave a greater plasma glucose response and a lesser hormonal response than a cooked flummery (containing cornstarch, protein and fat) in nondiabetics. In NIDD and IDD, however, the reverse applied for plasma glucose. In nondiabetics, cooked flummery gave a lesser glycemic response at some time points than uncooked flummery. In NIDD the opposite occurred. Cooking led to no significant change in insulin response in nondiabetics, but to a lesser insulin response in NIDD. The effect of some physical properties of food on diabetic control cannot be inferred from findings in nondiabetics.

Adult↗
PubMed1985

Plasma and serum concentrations of phenylbutazone and oxyphenbutazone in racing Thoroughbreds 24 hours after treatment with various dosage regimens.

The plasma and serum concentrations of phenylbutazone (PBZ) and oxyphenbutazone were measured in 158 Thoroughbred horses after various doses of PBZ wer given. All horses were competing or training at racetracks in various parts of the country. All horses used in the study had not been given PBZ 24 hours before they were placed on a specific dosage schedule. Samples were collected 24 hours after the last PBZ administration. Four grams of PBZ were given daily by stomach tube, paste, or tablet for 3 days. On day 4, 24 hours before sample collection, an IV dose of 2 g of PBZ was given, regardless of the dose and method of administration. The 24-hour PBZ plasma concentrations were 3.51, 6.13, and 6.40 micrograms/ml, respectively. After 2 g of PBZ was administered IV daily for 4 days, the plasma PBZ concentration was 4.16 g/ml; after a single 2-g IV administration, the serum concentration was 0.87 g/ml. Concentrations of oxyphenbutazone were 3.35 (stomach tube), 4.29 (paste), 3.60 (tablet), 3.65 (4-day IV), and 1.11 g/ml (single IV). A significant relationship was not found between the serum and the urinary concentrations at this 24-hour measurement. Split samples sent to various laboratories confirmed the stability of high-performance liquid chromatography as a method of analysis.

Administration, Oral↗
PubMed1984

Skeletal calcium homeostasis and countermeasures to prevent disuse osteoporosis.

Maintenance of a skeleton capable of resisting the stresses of everyday life is dependent on the mechanical forces applied to the skeleton during normal activity in a 1-G environment. When the effects of 1-G on the longitudinal skeleton are removed, as with space travel or inactivity, bone and bone mineral are lost because bone resorption is greater than bone formation. Ninety healthy young men were studied during 5-36 weeks of continuous bed rest. During inactivity, urinary calcium increases rapidly and by the sixth week of bed rest, output has risen by 100 mg/day, plateaus for several weeks, and then decreases but remains above ambulatory baseline thereafter. This occurred even though they received vitamin D supplements throughout the study. Calcium balance becomes negative after 2 weeks and by the end of the first month, 200 mg/day is lost. The loss continues at this rate for at least 36 weeks. Calcaneal mineral loses 5% of its mass each month. Attempts to prevent disuse osteoporosis with both mechanical and biochemical means, including exercise, skeletal compression, increased hydrostatic pressure to the lower body, supplemental calcium and/or phosphorus, calcitonin, or etidronate were not successful.

Adult↗
PubMed1984

Agglutinating antibody titers to members of the family Legionellaceae in cystic fibrosis patients as a result of cross-reacting antibodies to Pseudomonas aeruginosa.

The objective of this study was to evaluate the prevalence and significance of antibody titers to organisms in the family Legionellaceae in 128 serum samples collected from cystic fibrosis patients at routine examinations. Antibody titers were determined for 10 antigenic types of Legionellaceae; Legionella pneumophila serogroups 1 to 6, Fluoribacter (Legionella) bozemanae, Fluoribacter (Legionella) dumoffii, Fluoribacter (Legionella) gormanii, and Tatlockia (Legionella) micdadei. The method of antibody titer determination was the microagglutination test. Elevated titers (greater than or equal to 1:64) to one or more antigens were found in 41.3% of cystic fibrosis patients but in only 9.7% of 103 normal control subjects (P less than 0.01). Titers to 8 of the 10 antigens were directly correlated with the number of Pseudomonas aeruginosa precipitating antibodies in patient sera, as determined by crossed immunoelectrophoresis (correlation coefficients, greater than or equal to 0.74). Cross-reactions between P. aeruginosa and L. pneumophila were substantiated by crossed immunoelectrophoresis of hyperimmune rabbit serum as well as patient sera against P. aeruginosa and Legionellaceae antigens. Monospecific antibody to the "common antigen" of P. aeruginosa was used to demonstrate the presence of this antigen in L. pneumophila. The presence of cross-reacting antibodies in cystic fibrosis patients chronically infected with P. aeruginosa emphasizes the need for cautious interpretation of antibody titers to members of the family Legionellaceae.

Adolescent↗
PubMed1984

Ultrastructure of Prototheca zopfii in bovine granulomatous mastitis.

Mammary glands from cows with protothecal mastitis were examined by light and electron microscopy at 6, 13, 20, and greater than 180 days after infection. With increasing time, there were increases in severity of granulomatous inflammation, number of endospores and sporangia, and ratio of degenerate to intact algae. Algae were found in macrophages but were not seen in neutrophils, epithelial cells, or myoepithelial cells. Macrophages containing algae were markedly enlarged, chiefly from reduplication of the Golgi complex and its associated vesicles. Intracellular algae were degenerate and consisted of intact cell wall profiles which contained membrane fragments but lacked nuclei and cytoplasmic organelles. Degenerate algae in vitro had thin cell walls and did not undergo internal lysis. Cell wall material of intracellular algae stained as an acidic, nonsulfated, carboxylated glycoprotein. These findings suggest that intracellular Prototheca zopfii degenerate by progressive lysis of internal organelles with persistence of cell wall glycans and that development of aberrant cell wall forms occurs as a defective response by host macrophages.

Animals↗
PubMed1984

The correlation of changes in systolic blood pressure with regional anatomical regression of hypertensive left ventricular hypertrophy in patients on chronic antihypertensive therapy (greater than 1 year): alpha-methyldopa compared to propranolol.

Twenty patients with mild to moderate hypertension and evidence of left ventricular hypertrophy (relative wall thickness greater than or equal to 0.45), who previously had not received either alpha-methyldopa or propranolol, were allocated at random to treatment with one or other of these drugs as monotherapy after a 2-week baseline period on no medication. Dosage was titrated until normotension was attained and patients were then maintained on this treatment for a year. Analysis of blood pressure measurements and echocardiograms taken before and during maintenance therapy showed that there were significantly correlated changes in systolic blood pressure and heart rate with left ventricular cavity and regional wall changes during chronic drug administration. In the alpha-methyldopa group there were significant correlations between changes in erect and supine systolic blood pressure and the posterior wall index, and in erect systolic blood pressure and left ventricular mass. In the propranolol group, there were significant correlations between changes in supine systolic blood pressure and interventricular septal thickness, and in erect heart rate and supine systolic blood pressure with the percentage change in internal diameter of the left ventricle. It is suggested that these observations may have important therapeutic implications for hypertensive patients with documented left ventricular hypertrophy.

Adult↗
PubMed1984

Proliferation of lens epithelial explants in culture increases with age of donor rat.

Lens epithelial cells explanted together with their capsule into serum-free medium underwent cell division. The extent of cell division depended on the age of the donor rat. After explantation, lens epithelia from newborn and 5 day rats showed decreased mitotic activity from day 0 to day 3 whereas epithelia from 15 day rats showed a marked increase in mitotic activity which peaked at day 3. To determine the age when mitosis is first stimulated by explantation, explants were prepared from 10 day and 13 day rats. Explants from 10 day rats showed a slight increase in cell division and explants from 13 day rats showed a substantial increase in cell division. Therefore about 10 days of post-natal development, mitosis is stimulated by explantation and the magnitude of stimulation increased up to 15 days of age. We also found that in 7 week old rats the central epithelium, where most cells are blocked in Go-1 in vivo, showed a similar high level of cell division after 3 days. Moreover, the peripheral epithelium, which includes the zone of highest mitotic activity in vivo, had a significantly lower mitotic response to explantation than the central epithelium. Thus, explantation into serum-free medium must in some way stimulate cells blocked in Go-1 to re-enter the cell cycle. Furthermore, it is suggested that the increased mitotic response of rat lens epithelial cells with post-natal age indicates that the proportion of cells blocked in Go-1 increases substantially from 10-15 days of age.

Age Factors↗
PubMed1983

Dust exposure and mortality in an American chrysotile textile plant.

Three parallel cohort studies of asbestos factory workers were undertaken to investigate the effects of mineral fibre type and industrial process on malignant mesothelioma, respiratory cancer, and asbestosis. This report describes the mortality of a cohort of 2543 men, defined as all those employed for at least a month from 1938 to 1958 in a textile plant in South Carolina in which chrysotile was the only type of asbestos used. Of these, 863 men (34%) had died before 31 December 1977, one from malignant mesothelioma. Twenty one deaths were ascribed to asbestosis and 66 to cancer of the lung. Compared with the number expected from South Carolina, there was an excess of 30 deaths from respiratory cancer (ICD 160-164) in men 20 or more years after first employment (SMR 199.5). In men employed five years or more, no SMRs for this category rose above 300. Individual exposures were estimated (in mpcf X years) from recorded environmental measurements. Life table analyses and "log-rank" (case-control) analyses both showed a steep linear exposure-response that was some 50-fold greater at similar accumulated dust exposures than in Canadian chrysotile mining and milling. These findings agree closely with those from another study in this plant and confirm that mesothelioma is rarely associated with chrysotile exposure. Cigarette smoking habits did not greatly differ between the textile workers and the Canadian miners and millers. The far greater risk of lung cancer in the textile industry, if not attributable to other identified cocarcinogens, may be related to major differences in the size distribution of fibres in the submicroscopic range which are not detected by the usual fibre or particle counting procedures.

Adult↗
PubMed1983

Tularemia pneumonia mimicking legionnaires' disease: isolation of organism on CYE agar and successful treatment with erythromycin.

A 46-year-old man showed a clinical response when treated with parenteral erythromycin for what was initially thought to be legionnaires' disease, but an organism isolated from his pleural fluid on CYE agar was subsequently identified as Francisella tularensis. Tularemia should be suspected in all cases of atypical pneumonia in the appropriate setting. Erythromycin may be effective empiric therapy in such cases. Because of the possibility of inadvertent isolation of Francisella tularensis on CYE agar, all cultures for suspected Legionella should be handled with extreme caution, preferably in a biological hood.

Charcoal↗
PubMed1983

Leptospirosis--an occupational disease of soldiers.

Two cases of leptospirosis are described in soldiers who fell into a river together. One developed Weil's disease due to icterohaemorrhagiae serogroup and the other "Mud-Fever" due to grippotyphosa serogroup. The organisms were initially cultured in standard blood culture media. There were six cases of leptospirosis in BAOR in the 10 years to 1980 giving an incidence 10 times greater than in the civil population of UK and West Germany. Leptospirosis is an occupational disease of soldiers in BAOR and the health risks of fresh water immersion should be publicised.

Adult↗
PubMed1983

comparative analysis of cellular respiratory inhibition by substituted phenylglyoxal-bis-(4-methyl-3-thiosemicarbazone) zinc chelates.

Fourteen para-substituted phenylglyoxal-bis-(4-methyl-3-thiosemicarbazone) zinc chelates have been synthesized as inhibitors of cellular respiration and therefore as potential antineoplastic agents. Each chelate has been evaluated as an inhibitor of Ehrlich ascites tumor cell and of rat liver slice respiration. The molar I50 values for respiratory inhibition have been subjected to computerized correlation to delineate quantitative relationships between biological activity and chemical structure. Activity against the tumor cell model is characterized by a positive lipophilic and a detrimental steric influence while activity against rat liver slice displays only a weak positive lipophilic effect. Quantitative comparative analysis suggests that selective action against the tumor cell system can be improved by substituents which are electron withdrawing and lipophilic in nature.

Animals↗
PubMed1982

Urolithiasis in rats with diabetes insipidus (Brattleboro strain rats).

Brattleboro strain rats homozygous for hypothalamic diabetes insipidus (DI rat) excrete nearly their body weight per day in dilute urine and yet can form bladders stones composed of struvite and apatite. Studies were undertaken to investigate this apparent paradox. The results show that DI rat urine is indeed undersaturated with respect to struvite and apatite. However, chronic infection of DI rat urine with a urease-containing organism (Proteus mirabilis) results in the rapid formation of large struvite/apatite bladder stones. It is concluded that the Brattleboro strain DI rat, like man and unlike other rats, forms struvite/apatite calculi only in the presence at chronic urinary tract infection.

Animals↗