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Biomedical subjects

M MacDonald

Publications and source records attributed to M MacDonald.

At least 91 records · Page 5Linked to original sources
PubMed1985

The effect of continuous ambulatory peritoneal dialysis on diabetic eye complications.

Nine patients have been followed ophthalmologically since starting continuous ambulatory peritoneal dialysis (CAPD) for periods ranging from 16 to 48 months. All patients had eye disease related to their diabetes. Seven patients had proliferative diabetic retinopathy (PDR) and all these required laser treatment, six while undergoing CAPD. PDR was considered to have progressed during CAPD in four patients.

Adult↗
PubMed1984

Fluid migration through the tail of the Dalkon shield intrauterine device.

X-ray radiographs were used to monitor the migration of Renouve -dip radiopaque tracer through the multifilament tail of Dalkon Shield intrauterine devices (IUDs). The movement of the tracer was more rapid and migrated a greater distance through the long end of the tail than through the short end of the tail. The double knot serves as at least a temporary barrier to the migration of tracer from the long end of the tail, but this barrier was circumvented when drops of Renouve -dip radiotracer were placed at both ends of the tail. Migration of Renouve -dip radiotracer was prevented when the end of the Dalkon Shield tail was fused by heating. No migration of this tracer occurred on the tails of commonly used IUDs which possessed monofilament tails, thus demonstrating that fluid migration occurs within and not on the surface of the multifilament tail.

Capillary Action↗
PubMed1983

Inhibition of epidermal growth factor binding to Swiss 3T3 cells by human platelet release-products.

Human platelet ionophore release-products (IRP) inhibit the binding of 125I-labelled epidermal growth factor (125I-EGF) to its receptors on Swiss 3T3 cells. The inhibition appears to be caused by platelet-derived growth factor (PDGF) in the IRP and results from a decrease in the apparent affinity of cellular receptors for 125I-EGF. However, our results indicate that PDGF does not bind directly to EGF receptors, since (1) PDGF does not down-regulate EGF receptors; (2) the PDGF-mediated inhibition of 125I-EGF binding is temperature-dependent; (3) cells which possess EGF receptors but lack PDGF receptors do not exhibit a PDGF-mediated inhibition of 125I-EGF binding.

Animals↗
PubMed1983

Herpes simplex virus and congenital malformations.

We have reported a case of transplacentally transmitted herpes simplex virus (HSV) infection in association with both congenital malformations and other serious abnormalities, including facial abnormalities, microcephaly, cerebral atrophy, and microscopic cranial calcifications. Before death, the infant showed marked neurologic deficits, seizures, and respiratory distress. Serum IgM and complement fixing antibodies to HSV were elevated at birth. Light and electron microscopy and immunofluorescence studies confirmed the presence of the virus.

Abnormalities, Multiple↗
PubMed1981

Insanity and the realities of history in early modern England.

This paper argues that the attack on religious enthusiasm, a campaign against popular religious radicalism, prompted the governing classes in late seventeenth- and eighteenth-century England to embrace secular explanations of the nature of insanity and to repudiate treatments which were based on religious and magical beliefs. An objection to the argument is considered, and some of its implications are discussed.

England↗
PubMed1978

Effects of intraocular miotics on cultured bovine corneal endothelium.

Two cases of severe corneal oedema occurred after the use of intraocular pilocarpine. Experimental investigations were conducted with cultured bovine corneal endothelial cells exposed for 5 minutes to 1% pilocarpine solutions of varying composition. Cells were destroyed in solutions not isotonic with aqueous humour, and calcium-free ionic solutions caused loss of cell adhesion without loss of viability. Low pH or the presence of 1% pilocarpine had no detectable effects; 1% acetylcholine chloride in 5% mannitol (Miochol) also caused cell destruction, and this preparation was found to be considerably hypertonic. The minimum requirements for the formulation of intraocular miotics are discussed.

Acetylcholine↗
PubMed1977

The inner side of wisdom: suicide in early modern England.

This essay traces the shifting perception of the nature and prevalence of suicide in early England. Suicide is presented as one form of deviance contemporaries recognized and is used to illuminate the history of mental disorder in its social and intellectual context.

Attitude of Health Personnel↗
PubMed1976

Alanine metabolism and gluconeogenesis in the rat.

The metabolism of alanine and several other gluconegoneic substrates was studied in anesthtized fed and fasted rats, i.e., rats with low and high rates of gluconeogenesis. Glutamine was released by the hindquarter (muscle) in both groups, whereas lactate, pyruvate, and alanine were taken up in fed rats and were released during starvation. Despite this, blood levels of alanine, lactate, and pyruvate were diminished in fasting rats, suggesting increased extraction by liver. Treatment of fasted rats for 24 h with phloridzin caused glycosuria and secondarily led to hypoglycemia and an intensification of the chargesobserved with fasting, i.e., hyperketonemia, hyperglucagonemia, and increased gluconeogenesis (assessed by urea N excretion). Blood alanine was decreased, even though the release of alanine from muscle was increased. Pretreatment with triamcinolone and administration of exogenous alanine both attenuated the hypoglycemia and ketosis, It is concluded that 1) in states of heightened gluconeogenesis, alanine release from muscle may not keep pace with extraction by liver and blood alanine decreases; 2) the release of alanine, lactate, and pyruvate from muscle parallel each other suggesting common control factors; and 3) in the red state muscle is an important site of lactate disposition.

Alanine↗
PubMedDate not supplied

Aerosol delivery to the rabbit lung with an infant ventilator.

Little is known about delivery of aerosolized medications to infants undergoing assisted positive pressure ventilation. To assess delivery of medications to the lung with an infant ventilator (Bournes LS104), 27 experiments were performed on anesthetized adult rabbits. Lung deposition was determined by using aerosol radiolabeled with 99m technetium sulfur colloid. Initially a traditional nebulizer was studied and very inefficient delivery to the lung was observed (0.19 +/- 0.10 SD% of the initial nebulizer dose). Subsequent experiments using a nebulizer that generates submicronic aerosol particles, at equivalent aerosol output, achieved a highly significant increase in delivery (1.96 +/- 1.19 SD%, P less than 0.001). Our experiments demonstrated that modifications to to traditional nebulizer systems can enhance delivery of aerosolized medication to the lungs of rabbits.

Aerosols↗
PubMedDate not supplied

House officer interviewing techniques: impact on data elicitation and patient perceptions.

The relationships among physicians' interviewing techniques, the amount and type of data gathered, and patients' perceptions of the interviewing process were studied. Thirty-one Internal Medicine house officers each interviewed one of three standardized patients. The house officers' thoroughness of data collection was assessed by the patients and by a trained evaluator. A videotape of each interview was analyzed at the National Board of Medical Examiners using the interaction analysis system for interview evaluation, ISIE-81, to define house officers' interviewing techniques. From the physicians' problem-solving perspective, data elicitation was positively related to the length of the interview, asking psychosocial questions, the use of narrow questions, and the amount of time the patient talked. The patients' assessments of house officers' data-gathering thoroughness were also positively influenced by interview length, the use of narrow questions, and inquiries about their psychosocial histories. The use of broad questions by the house officer was positively related to the patient's feelings about and reaction to the interaction. This study potentially explains some of the differences that appear to exist between patients' and physicians' judgments about and perceptions of the medical interviewing process.

Aged↗
PubMedDate not supplied

Cancer coverage in mass-circulating Canadian women's magazines.

Mass media can inform health beliefs and shape cancer control behaviours. This study surveyed cancer coverage in 309 issues of Canadian women's magazines for the period 1991-1997. Magazines were selected if 1996 revenue > $10 million and circulation > 500,000; Canadian Living, Chatelaine, Flare and Homemaker's met these criteria. The volume of cancer coverage varied significantly by year and by magazine. However, coverage of specific cancers did not reflect their contribution as a cause of cancer death in Canadian women. The percentage of articles on lung cancer was lower and on breast cancer was higher than the percentage of deaths due to these cancers. All magazines had decreased coverage of lung cancer in 1997 compared to 1991. National cancer resource agencies and research initiatives on breast cancer were infrequently mentioned. These results argue for greater partnerships between the media and health educators to enhance balanced dissemination of cancer control information to Canadian women.

Canada↗
PubMedDate not supplied

Cancer coverage in newspapers serving large and small communities in Ontario.

Local newspapers are an important source of health news, especially in small communities. We describe the amount and type of cancer information in Ontario daily newspapers dichotomized by circulation size (> 400,000 or < 40,000) and community size (> 250,000 or < 25,000 people) for 1991. All cancer articles (n = 1027) in five newspapers with large circulations, serving large communities, and five newspapers with small circulations, serving small communities, were read and evaluated for focus and newsplay. Although large newspapers had an absolute greater number of cancer articles, there were no significant differences by newspaper size in the number of cancer articles per 1,000 pages. Large newspapers included more cancer articles with a scientific vs. human interest focus than did small newspapers (p < 0.001). Large newspapers tended to use wire services whereas small newspapers tended to use staff reporters. Differences in the type and amount of cancer information varies by newspaper and community size, potentially contributing to differences in community cancer information resources.

Health Resources↗