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Biomedical subjects

A Hall

Publications and source records attributed to A Hall.

At least 397 records · Page 22Linked to original sources
PubMed1985

Effects of an intravenous bolus calcium injection on glomerular filtration rate and electrolyte excretion in the kidney in conscious pigs.

This paper reports the changes observed in the concentration of various constituents of plasma and in their excretion in the urine after a bolus intravenous injection of 2,2 mM calcium gluconate into conscious pigs weighing 20 kg. In the plasma, both ionic and total calcium concentrations increased but returned to normal within 35 minutes, while sodium, potassium and inorganic phosphate did not change significantly. In the kidney, the urine volume, glomerular filtration rate (GFR) and fractional sodium excretion increased slightly during the first 10 minutes but became significantly depressed later. Potassium and phosphate levels decreased, the latter significantly, while the calcium concentration increased significantly and only returned to normal after 70 minutes. These results suggest that since the disturbances in urinary volume, GFR and fractional phosphate excretion persist after both the plasma calcium and urinary calcium levels have returned to normal, factors other than these calcium values may be responsible for changes in the former measurements.

Absorption↗
PubMed1985

Anorexia nervosa in the male: clinical features and follow-up of nine patients.

Nine male patients formed approximately 5% of patients presenting with anorexia nervosa from a population area. Their clinical and family features and outcome at a mean of 5 1/2 yr from onset were similar to those of female patients. All patients lost libido during the syndrome. In four patients at average weight at follow-up the level of libido and sexual activity was related to testosterone level, other hormonal investigations being normal in post pubertal patients. All patients had a history of increased attention to bodily appearance and/or diet before the onset of the illness (e.g. aberrant body size or appearance, close contact with an eating disorder patient).

Adolescent↗
PubMed1985

Long-term inhalation toxicity of hydrazine.

Year-long intermittent exposures of rats, mice, hamsters, and dogs to hydrazine were conducted using concentrations of 0.05, 0.25, 1.0, and 5.0 ppm. Rats were held 18 months postexposure; hamsters, 1 year postexposure; mice, 15 months postexposure; and dogs, 38 months postexposure. Male and female rats exhibited dose-dependent incidences of benign nasal adenomatous polyps and smaller numbers of malignant nasal epithelial tumors after 1 year of exposure to hydrazine and 18 months postexposure holding. Nasal tumors were often associated with chronic irritation and were most frequent in male rats, with an incidence of greater than 50% in the highest exposure group. Hamsters exposed to 0.25-ppm and higher concentrations showed pathologic changes characteristic of degenerative disease, including amyloidosis. After exposure to 0.5 ppm hydrazine, hamsters developed a 10% incidence of benign nasal polyps compared to 0.5% in controls. Small numbers of colon neoplasms and thyroid parafollicular cell adenomas were found in hamsters, but only in the highest concentrations tested. Lung adenomas appeared to be marginally increased in mice exposed to 1.0 ppm hydrazine, the highest concentration tested in this species. No consistent clinical or pathological effects were seen in dogs during or after exposure to hydrazine at any concentration. Using amyloidosis as a criterion, a no-effect level was not achieved in hamsters. In rats, there appeared to be a marginal production of nasal tumors at 0.05 ppm, while mice showed no effects at 0.25 ppm. This study has demonstrated that the nasal respiratory epithelia of rats and hamsters are the most sensitive tissues to the tumorigenic action of hydrazine following inhalation exposures. This is similar to the reaction of rats to formaldehyde, another highly reactive water-soluble compound.

Animals↗
PubMed1985

Activation of an N-ras gene in acute myeloblastic leukemia through somatic mutation in the first exon.

A transforming N-ras gene has been cloned from acute myeloblastic leukemia bone marrow cells, in parallel with the N-ras gene derived from fibroblasts of the same patient. N-ras derived from fibroblasts lacked focus-forming activity in NIH/3T3 cells, indicating that gene activation in the leukemia cells must have occurred by a somatic event. Construction of chimeric molecules between the transforming and the normal N-ras genes and subsequent biological and sequence analysis of these constructs revealed that the transforming gene was altered by a point mutation changing amino acid 12 of the N-ras protein from glycine to aspartic acid.

Alleles↗
PubMed1985

Digital radiographic evaluation of the bile ducts.

This study compares digital radiographic images of the bile ducts in dogs with images obtained using routine radiography. The dogs were infused with iodipamide (2 ml/minute for 30 minutes), and the bile ducts were imaged at 60 minutes using plain radiograph and five digital techniques: (1) dual-energy, (2) DSA-hybrid prepixel shift, (3) DSA-hybrid postpixel shift, (4) a dual-energy film system--Digirad, and (5) scan projection radiography using hybrid subtraction. Six radiologists who were not familiar with digital radiography evaluated the six different studies. The images were presented in a randomized order and each image was evaluated on a five-point scale. There was no difference between the plain radiographs and the dual-energy images. Both of these studies were rated significantly better (P less than .001) than the other four digital images. These results suggest that digital radiography during direct cholangiography may be easily accomplished using a 10% to 15% iodine solution.

Animals↗
PubMed1985

Nutritional aspects of parasitic infection.

The nutritional basis of the ecological relationship between parasites and their hosts is reviewed using examples of the parasitic infections of man whenever possible. Two important points are discussed first: the distinction between parasitic infection and parasitic disease, and the concepts of synergism or antagonism between undernutrition and parasitic disease. The effects of parasites on the nutritional status of the host are examined in four ways. First, in terms of the ways in which parasites can disturb nutritive processes by effects on physical activity to obtain food, and by effects on food consumption, digestion and absorption. Secondly, in terms of the nutritional cost of an infection to a parasitised host. Thirdly, in terms of the feeding, nutrition and metabolism of parasites. Finally, in terms of damage to the tissues of the host caused by parasites. Two other sections deal briefly with the transmission of parasites in food and the effects of food on parasites.

Animals↗
PubMed1984

Mechanism of activation of an N-ras gene in the human fibrosarcoma cell line HT1080.

A full length N-ras gene has been cloned from both the human fibrosarcoma cell line HT1080 and from normal human DNA. N-ras isolated from HT1080 will efficiently induce morphological transformation of NIH/3T3 cells in a transfection assay, whereas N-ras isolated from normal human DNA has no effect on NIH/3T3 cells. The coding regions of the normal N-ras gene have been sequenced and the predicted amino acid sequence of the N-ras product is very similar to that of the c-Ha-ras1 and c-Ki-ras2 products. By making chimeric molecules between the two cloned genes the activating alteration in the HT1080 N-ras gene has been localised to a single base change that results in an amino acid alteration at position 61 of the p21 N-ras product.

Amino Acid Sequence↗
PubMed1984

Anorexia nervosa: long-term outcome in 50 female patients.

Fifty consecutively referred female patients with anorexia nervosa were followed-up to identify those completely healthy at a minimum of four years (mean eight years) since onset. As well as using Morgan's Outcome Measures, an independent psychiatrist elicited details of food/weight pre-occupation and psychiatric state. The outcome results, based on weight and menstruation, (36% 'good', 36% 'intermediate', and 26% 'poor' including 2% dead, and 2% not assessed) did not differ significantly from those of the three similar published studies on similar patients; 62% of patients continued to have some food/weight pre-occupation. DSM III criteria for a psychiatric disorder other than eating disorder were fulfilled by 50%; dysthymic disorder was common (34%), occurring exclusively in patients with continuing eating disorder symptoms, while only 20% of the sample were free of any physical or mental abnormality. Of 52 prognostic factors studied, only four were significantly related to the outcome measures. Length of illness at presentation was the only prognostic factor common to all four similarly conducted studies.

Adolescent↗
PubMed1984

Anorexia nervosa: a study of 34 twin pairs and one set of triplets.

In a collaborative study between St George's and the Maudsley Hospitals, 34 pairs of twins and one set of triplets were identified in which the proband had anorexia nervosa. The diagnosis was based on standard criteria and zygosity was established by blood group analysis or by use of the physical resemblance questionnaire. In the 30 female twin pairs, 9/16 of the monozygotic (MZ) and 1/14 of the dizygotic (DZ) pairs were concordant for anorexia nervosa. Three of the non-anorexia co-twins had other psychiatric illnesses, and two had minor eating disorders. None of the male co-twins had anorexia nervosa.

Adult↗
PubMed1984

Are acid and pepsin reduction the only effects of highly selective vagotomy. Evidence of changes in tissue levels of gastrin, prostaglandins and lysosomal acid hydrolases in an experimental ulcer model.

Using the bile duct ligated (BDL) pig as a model of experimental peptic ulceration, a study was made of the effects of highly selective vagotomy (HSV) upon basal and stimulated acid and pepsin secretion, tissue levels of n-acetylglucosaminidase, prostaglandins (PgE2) and gastrin, and gastric venous plasma gastrin. In addition to reducing basal acid and pepsin output, HSV was found to return towards normal the elevated tissue prostaglandin and depressed antral gastrin levels after BDL. In addition, it was observed that gastric juice specimens were markedly viscid. It is suggested that there may be effects of HSV other than acid and pepsin reduction which require attention.

Acetylglucosaminidase↗
PubMed1983

Localisation of the human N-ras oncogene to chromosome 1cen - p21 by in situ hybridisation.

The N-ras gene is a transforming gene isolated from a variety of human tumour cell lines and is a member of a family of related ras genes. Somatic cell hybrids have previously shown that the N-ras gene is located on chromosome 1. We have confirmed this localisation by in situ hybridisation to metaphase preparations of lymphocytes and localised the gene to the region 1cen - p21. A survey has found 47 reported cases of malignancy involving deletions in the short arm of chromosome 1. Fifteen of the 47 involved a deletion in this region.

Chromosome Mapping↗
PubMed1983

Parasitic infections, anaemia and nutritional status: a study of their interrelationships and the effect of prophylaxis and treatment on workers in Kwale District, Kenya.

A study was conducted between January and August 1979 on 150 male roadworkers in Kwale District in the coastal lowlands of Kenya. At the baseline examination 59% had hookworm (mean of 227 epg +/- 541), 38% had infections of Schistosoma haematobium (mean 52 +/- 82 ova per 10 ml urine), 23% had a blood film positive for malarial parasites, 47% had anaemia (Hb below 13g/dl), and 31% had a percentage weight for height below 80% of a reference value for healthy men. It was found that anaemia was significantly associated with hookworm infections and egg counts. Three interventions were evaluated. These consisted of providing pyrantel pamoate for hookworm to all men, treating the S. haematobium infections with metrifonate, and giving weekly chloroquine prophylaxis for suppression of malaria to one group of men. A final examination conducted 16 weeks later showed a significant improvement in haemoglobin levels in anaemic men treated for hookworm and in those receiving chloroquine compared with those receiving placebos. Multiple regression analyses revealed that both hookworm and S. haematobium egg counts were associated with anaemia at the baseline examinations, that factors related to the treatment of hookworm and prophylaxis for suppression of malaria were related to haemoglobin increases in anaemic men, and that successful treatment of urinary schistosomiasis was associated with weight gain. The feasibility of the interventions was good and the costs moderately low.

Adolescent↗
PubMed1983

Induction of monocytic differentiation and bone resorption by 1,25-dihydroxyvitamin D3.

1,25-Dihydroxyvitamin D3 [1,25(OH)2D3] stimulates bone resorption in man and other vertebrates, in part, by increasing the number of osteoclasts, the principal resorbing cells of bone. Because osteoclasts are very likely derived from a member(s) of the mononuclear phagocyte family, we determined if 1,25(OH)2D3 promotes maturation of these cells by studying its effects on the human promyelocytic leukemia cell line HL-60. Of the vitamin D3 metabolites tested, only 1,25(OH)2D3, at 10(-10) to 10(-7) M, induces the differentiation of HL60 into mono- and multinucleated macrophage-like cells. Phenotypic change is evident within 24 hr and reaches a plateau between 72 and 96 hr of incubation. The changes are metabolite-specific and include (i) adherence to substrate, (ii) acquisition of the morphological features of mature monocytes, (iii) a 4- to 6-fold enhancement in lysozyme synthesis and secretion, (iv) increase in the fraction of alpha-naphthyl acetate esterase-positive cells from approximately 2% to 100% of the population, and (v) the acquisition of several monocyte-associated cell surface antigens. More importantly, treated HL-60 cells acquire the capacity to bind and degrade bone matrix, two of the essential, functional characteristics of osteoclasts and related bone-resorbing cells. These results, considered together with the reported action of 1,25(OH)2D3 on nontransformed mononuclear cells, are consistent with the view that vitamin D3 enhances bone resorption and osteoclastogenesis in vivo by promoting the differentiation of precursor cells.

Animals↗
PubMed1983

Dietary protein and the growth of rats infected with the tapeworm Hymenolepis diminuta.

1. Weanling rats fed on a relatively low protein diet were infected with several intestinal tapeworms. The weight gain and daily food intake of the rats were measured for 3 weeks before the animals were killed and the adult tapeworms recovered. The tissues of the rats and worms were then analysed for protein. Controls were provided by uninfected rats either pair fed or fed ad lib. For comparison, a similar experiment was conducted on rats fed on a relatively high protein diet. 2. The effect of the infection on the protein-malnourished rats and of the low level of protein on the worms were apparently not significant. The amount of protein contained in the worm burdens was less than 1.5% of the average total intake of the protein-malnourished rats.

Animals↗
PubMed1983

A comparison of the attitudes of young anorexia nervosa patients and non-patients with those of their mothers.

Attitudes towards 'sickness', 'arguments', 'tension', 'social isolation', 'thinness', 'growing up' and 'grown up' were investigated in 20 young female anorexia nervosa patients and their mothers, and in 32 volunteer non-patient schoolgirls and their mothers. A computer-generated semantic differential questionnaire was completed by each daughter and her mother, first for herself and then as she thought the other person would have answered it. The majority of significant differences occurred between the anorexic daughters and their mothers as a group, and the non-patient daughters and mothers as a group. The anorexia nervosa group rated 'sickness', 'arguments' and 'tension' more favourably than did the non-patients, while the patients rated 'thinness' and 'social isolation' less favourably than did the non-patient group. Neither group of mothers and daughters consistently misjudged each other.

Adolescent↗