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Biomedical subjects

J McIntosh

Publications and source records attributed to J McIntosh.

At least 73 records · Page 4Linked to original sources
PubMed1986

Effects of NaCl on calcium balance, parathyroid function and hydroxyproline excretion in prednisolone-treated rats consuming low calcium diet.

The short-term effects of dietary sodium chloride supplementation on calcium balance were examined in an animal model of corticosteroid-mediated osteoporosis. Changes in calcium and phosphate balance, parathyroid function and bone resorption elicited by salt supplements alone (8 g/100 g diet), prednisolone alone (2.2 mg/kg body wt per day) and both salt and prednisolone in combination were measured in rats consuming a low calcium diet (0.1% calcium) for 10 d. Parathyroid function was monitored by measuring urinary cyclic AMP excretion. Bone resorption was monitored by measuring urinary hydroxyproline excretion. Salt alone raised urinary calcium, cyclic AMP and hydroxyproline; prednisolone alone depressed net calcium absorption and urinary hydroxyproline but had no effect on urinary calcium. Salt and prednisolone each depressed calcium retention independently and together produced an additive adverse effect on calcium balance. Thus high dietary salt intakes augment urinary calcium loss, raise parathyroid activity, increase bone resorption and adversely affect calcium balance in prednisolone-treated growing rats with a restricted dietary calcium intake. These findings support the view that high salt intakes may exaggerate bone loss during chronic glucocorticoid therapy. Because people also develop osteoporosis during glucocorticoid therapy and respond to dietary salt supplements by increasing urinary calcium excretion and parathyroid hormone, high salt intakes may accelerate bone loss in patients receiving chronic glucocorticoid therapy. The beneficial effects of dietary salt restriction on the conservation of bone mass warrant investigation in these patients.

Absorption↗
PubMed1986

The use of color in the environment of the elderly to enhance function.

Empirical evidence suggests that the functional level of the institutionalized elderly is favorably affected by enriching the environment with the specific use of color and light. Evidence of the validity of this supposition would form a worthwhile contribution to geriatric rehabilitation by promoting the independence of the elderly in the area of activities of daily living. The quality of literature on the appropriate use of environmental color for an institutionalized geriatric population is limited, being primarily descriptive in nature. In general, visual enhancement by the selective use of color is advocated to minimize the adverse effects of sensory deprivation and to enhance mood, whereas color coding and cueing are directed toward improving function. Faced with a variable literature base and a scarcity of studies that scientifically approach the question of what effect visual enhancement might have on function in the elderly, the authors of this paper are conducting a pilot study with the following objectives: To demonstrate that color cueing (in the form of color contrast applied to key objects in the environment) and increased lighting can enhance the performance of activities of daily living in an institutionalized elderly population. To study the concept that improvement in activities of daily living corresponds with improvement in the patient's mood and feelings of self-worth. To evaluate the effect of color and lighting changes in the environment on various aspects of behavior. It is hypothesized that improvement in behavior will accompany increased functional independence. Thus, we would expect to see a relationship between aspects of behavior and those aspects of mood and activities of daily living currently under investigation.

Aged↗
PubMed1985

Potassium bicarbonate supplementation blocks the hypocalciuric response to hydrochlorothiazide in rats.

Bicarbonate salts and thiazide diuretics each lower urinary calcium excretion. This study was undertaken to compare the effects of administering oral sodium or potassium bicarbonate supplements (4.5 mmol./day of each salt) each with or without hydrochlorothiazide (10 mg./kg. body weight/day) on urinary calcium excretion in rats. Urinary calcium decreased (p less than 0.01) by about 50 per cent after sodium bicarbonate supplementation and potassium bicarbonate supplementation. The hypocalciuric response to each bicarbonate salt was similar. However, although hydrochlorothiazide depressed urinary calcium in rats consuming sodium bicarbonate, rats receiving equimolar supplements of potassium bicarbonate did not lower urinary calcium when given hydrochlorothiazide, despite evidence of the expected thiazide-mediated diuresis. It is concluded that in the rat potassium bicarbonate loading blocks the ability of hydrochlorothiazide to lower urinary calcium excretion.

Animals↗
PubMed1985

Hydrochlorothiazide lowers urinary hydroxyproline in parathyroidectomized rats.

This study was undertaken to examine the effects of hydrochlorothiazide treatment on urinary hydroxyproline excretion in parathyroidectomized rats. Urinary hydroxyproline (mumol/24 hr) fell significantly in thiazide-treated rats compared with control animals (5.66 +/- 0.37 versus 7.30 +/- 0.6, P less than 0.05, means +/- SEM). This fall in hydroxyproline excretion occurred without a decrease in glomerular filtration rate. It is concluded that the ability of thiazide diuretics to reduce urinary hydroxyproline excretion is not dependent upon suppression of parathyroid hormone-mediated bone turnover.

Animals↗
PubMed1985

Problem solving in undergraduate medical students.

In recent years the systematic development of the skill of clinical reasoning has come to assume a high priority as an explicit aim of medical education. Clinical reasoning, it is contended, is the application of general reasoning and problem-solving skills to the specific knowledge base of medicine. The results presented in this paper constitute a preliminary study designed to investigate the ability of first-year medical undergraduates to solve abstract problems using a simple nonmedical knowledge base. Further studies are being carried out and will continue to extend this into the specific medical knowledge base area. The potential implications for medical education and the development of clinical reasoning are discussed.

Clinical Competence↗
PubMed1984

The stability of the o-phthalaldehyde/2-mercaptoethanol derivatives of amino acids: an investigation using high-pressure liquid chromatography with a precolumn derivatization technique.

The investigation of the stabilities of o-phthalaldehyde/2-mercaptoethanol derivatives of amino acids using a precolumn reaction technique and a high-pressure liquid chromatographic procedure is reported. The amino acid derivatives are shown to be stable on the high-pressure liquid chromatography column. Optimal conditions for the development of these derivatives for their separation using this technique are recommended.

Aldehydes↗
PubMed1984

Effects of sodium bicarbonate and 1,25-dihydroxy-cholecalciferol on calcium and phosphorus balances in the rat.

Metabolic balance studies were undertaken to determine whether sodium bicarbonate (NaHCO3) supplements (4.5 mmol/day) altered 7-day cumulative calcium (Ca) phosphorus (P) balances in growing rats consuming either a basal diet providing 0.6% Ca and 0.3% P, or this diet plus 1,25-dihydroxycholecalciferol [40 ng 1,25(OH)2D3/day]. Feeding bicarbonate lowered urinary Ca but raised fecal Ca so that Ca balance became less positive. However, 1,25(OH)2D3 increased net absorption of Ca and P to the same degree when given to control rats and rats consuming bicarbonate. Nevertheless, bicarbonate-fed rats had lower net Ca absorption than controls, even when treated with high doses of 1,25(OH)2D3. Changes in net Ca absorption induced by bicarbonate may occur at a point in the gut distal to the duodenum since duodenal 45Ca absorption was decreased by bicarbonate feeding. The present results show that bicarbonate consumption depressed net Ca absorption in the rat. The effect appears to be independent of changes in 1,25(OH)2D3 metabolism because it is manifest in animals receiving high doses of 1,25(OH)2D3, which stimulate alimentary Ca absorption maximally, and because bicarbonate-fed rats are able to respond normally to exogenous 1,25(OH)2D3 by increasing their net absorption of Ca and P. In view of this demonstration that NaHCO3 supplements elevate fecal Ca loss in the rat, it is suggested that studies should be undertaken to determine whether bicarbonate exerts similar adverse effects on Ca balance in humans.

Absorption↗
PubMed1984

Controlled comparison of plasma and serum for cystic fibrosis protein.

Investigators who have previously reported attempts to utilize the isoelectric focusing (IEF) method to detect the cystic fibrosis protein (CFP) in blood samples from CF homozygotes and heterozygotes, and normal healthy controls have restricted their evaluations to serum samples. The requirement of using serum and the stringent conditions laid down for the collection, processing, and storage of serum samples have been impediments, however, to the successful use of the IEF method for CFP detection. We now report results obtained from controlled ("blind") comparative analyses of matched serum and plasma samples from CF homozygotes and heterozygotes, and normal healthy controls which indicate that the CFP is present in plasma and that heparinized plasma in particular may be a better fluid than serum for use in future studies on the CFP.

Blood Protein Electrophoresis↗
PubMed1984

Smoking, alcohol, analgesics, and chronic duodenal ulcer. A controlled study of habits before first symptoms and before diagnosis.

The aim of the study was to investigate the role of smoking and alcohol and analgesic ingestion in the aetiology of chronic duodenal ulcer (DU). Exposure to these variables was studied during the lifetime and 1 year before the first ulcer symptom and 1 month before a diagnosis. The ulcer group of 100 patients was compared with 100 community controls matched for age, sex, and social grade. In men there was an increased risk of DU associated with smoking and alcohol ingestion both during the lifetime and 1 year before the first symptom. In women, there was an increased risk associated with smoking during the lifetime before the first symptom and with alcohol ingestion during the year before the first symptom. Analgesic ingestion was not a risk factor. In the month before diagnosis only smoking was commoner in the DU group. The data indicate that smoking and alcohol ingestion are risk factors for DU.

Age Factors↗
PubMed1982

Lumbar disc disease.

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Clinical Trials as Topic↗
PubMed1980

The location of chronic gastric ulcer: a study of the relevance of ulcer size, age, sex, alcohol, analgesic intake and smoking.

Ulcer size, age, sex, alcohol and analgesic intake and cigarette consumption were studied in relation to the site of the ulcer in 215 patients with chronic gastric ulcer, of whom 96 were initial and 115 recurrent ulcers. Ulcer site was classified into upper (U), middle (M) and lower (L) thirds of the stomach, on X-ray films of air-contrast barium studies. The ulcers were situated in the upper third in 37 patients (17%), middle third in 90 patients (42%) and lower third in 88 patients (41%), i.e., significantly more in M and L compared to U (p less than 0.001). 135 ulcers were on the lesser curve (63%) with more in L and M compared to U (p less than 0.0005). Posterior wall ulcers accounted for 29.3%. Ulcers were smallest in L (mean 28.8 mm2) compared to those in M (mean 66.1 mm2) and U (mean 64.4 mm2) (p less than 0.001). Mean size overall was 49.0 mm. The mean age of the patients was 58.8 years with no significant differences in age between U, M and L (p greater than 0.9). The M/F ratio in the whole series was 0.6 which varied with ulcer site, being 0.3 in U (differing significantly from the whole series, p less than 0.05), 0.4 in M and 1.2 in L (significantly different from the whole series, p less than 0.01) and from U (p less than 0.01). Initial ulcers did not differ from recurrent ulcers except in women where initial ulcers were more common in M and L, whereas recurrent ulcers were more commin in U. The independent variables, namely, alcohol and analgesics (with the exception of smoking), were not determinants of ulcer site, size or position once the patients were segregated by sex. In men only, there were interactions between L and lesser curve site (p less than 0.004) and L and smoking (p less than 0.03).

Age Factors↗
PubMed1979

Circulating immune complexes in acute uveitis: a possible association with the histocompatibility complex locus antigen B27.

39 patients with acute anterior uveitis were investigated for the presence of circulating immune complex (IC) and correlation with the major histocompatibility complex antigen B27 (HLA-B27). ICs were demonstrated by a number of techniques including rheumatoid factor, complement (C) activation, anticomplementary activity, cryoglobulins, inhibition of IgG-EA rosette formation and neutrophil chemotactic index (NCI) in plasma. ICs were most frequently detected in HLA-B27-negative patients. These results indicate that deposition of circulating ICs may be involved in the pathogenesis of acute anterior uveitis, especially in HLA-B27-negative patients.

Acute Disease↗