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Biomedical subjects

L Reynolds

Publications and source records attributed to L Reynolds.

At least 73 records · Page 4Linked to original sources
PubMed1992

Cattle production systems in the derived Savannah and southern Guinea Savannah regions of Oyo State, southern Nigeria.

A single visit questionnaire survey was undertaken on 50 cattle owners in Oyo State, south-western Nigeria. Data were collected on grazing patterns, calving dates, calf mortalities and attitudes to the N'Dama breed and its crosses with Bunaji cattle. All cattle herds had similar grazing patterns, using natural pasture from April to November, crop residues in December, pasture regrowth after burning plus crop residues in January and regrowth and browse in February and March. The conception pattern was unimodal, reaching a peak in July after the new grass growth from the first rains. Calf mortalities were highest between 2 to 4 months of age during the early rainy season, but were significantly lower in mixed N'Dama/Bunaji herds than in the Bunaji herds. Most cattle owners were interested in purchasing N'Dama breeding stock, believing them to be more productive. This is a move away from the traditional pastoralist practice of keeping only Bos indicus breeds.

Animal Husbandry↗
PubMed1992

Hearing thresholds in CAPD patients.

Ultra high frequency (UHF, 10-20 kHz) and conventional audiometric thresholds (0,25-8 kHz) were obtained from 42 stable CAPD patients. Twenty-one (50%) and 11 (25%) of the patients had UHF and conventional hearing loss respectively, when compared to age related control data. This was unrelated to length of chronic renal failure and number of treatments with ototoxic drugs. Sixteen of these patients were monitored audiometrically using UHF during a course of vancomycin therapy for peritonitis. There was no significant change in hearing thresholds. In conclusion there is high incidence of hearing loss in CAPD patients which is unrelated to ototoxic drugs.

Adult↗
PubMed1991

High frequency thresholds: variations with age and industrial noise exposure.

The effects of age and noise exposure were investigated. 97 normal subjects representing 6 age groups were tested with both conventional pure tone audiometry and high frequency audiometry (10-20 kHz) using a commercial high frequency audiometer. Thresholds were obtained by means of earphones as opposed to a quasi-free field technique. The results were discussed in terms of the age effect. In addition, conventional and high frequency thresholds were obtained for 64 subjects who had a history of industrial noise exposure representing 4 age groups. Significant differences were found between the noise exposed group and the normal subjects. The implications of the results are discussed.

Adolescent↗
PubMed1989

Evidence for non-lysosomal storage of N-acetylneuraminic acid (sialic acid) in sialuria fibroblasts.

The results of the investigations reported here indicate that patients affected with the infantile sialic acid storage disorder (ISSD) and the original French sialuria patient suffer from distinct and fundamentally different disorders. While phase microscopy and immunochemical studies demonstrated abnormal storage within intracellular inclusions in ISSD cells, no morphological evidence of storage within any subcellular organelles was found in the sialuria cells. Moreover, comparative subcellular fractionation studies on gradients of colloidal silica showed the excess sialic acid in ISSD cells to be located within the light (buoyant) lysosomal fraction, while the excessive, free sialic acid in the sialuria cells was found in the cytoplasmic fraction with no increased storage within the lysosomal fractions. It is concluded that the sialic acid abnormalities in ISSD and the French type of sialuria are the result of very different biochemical and genetically unrelated abnormalities.

Fibroblasts↗
PubMed1988

Ubiquitin is a common factor in intermediate filament inclusion bodies of diverse type in man, including those of Parkinson's disease, Pick's disease, and Alzheimer's disease, as well as Rosenthal fibres in cerebellar astrocytomas, cytoplasmic bodies in muscle, and mallory bodies in alcoholic liver disease.

Polyclonal antibodies were raised which have a high affinity for conjugated ubiquitin. Immunocytochemistry was performed on paraffin sections of tissues showing well-characterized inclusion bodies. Ubiquitin was found as a component of the intermediate filament inclusion bodies characteristic of several major diseases including Lewy bodies of Parkinson's disease, Pick bodies of Pick's disease, Mallory bodies of alcoholic liver disease, cytoplasmic bodies of a specific myopathy, and Rosenthal fibres within astrocytes. Ubiquitin was also present in the three histological lesions characteristic of Alzheimer's disease. These observations suggest a fundamental role for ubiquitin in the formation of intermediate filament inclusion bodies in man, and have implications regarding the pathogenesis of these important diseases.

Alzheimer Disease↗
PubMed1987

Purification and characterization of sialic acid containing materials accumulated in cultured skin fibroblasts from a patient with type II sialidosis.

Sialyl conjugates which accumulate in sialidase deficient fibroblasts were made radioactive in the sialic acid moiety by culturing the cells in the presence of [3H]N-acetylmannosamine. The accumulated radioactive compounds were fractionated by anion exchange chromatography and gel filtration. At least nine chromatographically distinct sialyl conjugates were obtained. Neutral and amino sugar analysis of these compounds indicated that all were sialyloligosaccharides of the type which could be derived from glycoproteins containing complex, N-asparagine-linked carbohydrate groups.

Cells, Cultured↗
PubMed1987

Pulmonary microembolism: a cause of lung injury.

Microthrombi found in the pulmonary capillaries in patients dying with post-traumatic pulmonary insufficiency suggests that pulmonary microembolism (PME) may be etiologically important, but a temporal relationship has not been demonstrated. We used a modified Lim-Blaisdell model of PME to cause a severe ischemic soft tissue injury in dogs. The appearance of microaggregates (MA) in the venous circulation was measured using a laser optical scanning technique. The effect of MA on pulmonary physiologic and histologic parameters was measured and compared to control animals. In the ischemic soft tissue injury group, following restoration of local circulation, the platelet count dropped by 72% (P less than 0.00002), the number of MA increased by 800% (P less than 0.00002), the mean pulmonary artery pressure (PA) increased from 15.6 to 32 mm Hg (P less than 0.00002), and electron micrographs of lung obtained at 4 hr after ischemic insult revealed PM with severe lung injury that was consistent with a capillary membrane leak. The control group never demonstrated a significant change in platelets, MA, PA, or histologic lung injury. These findings imply that MA found in the pulmonary microcirculation are temporally related to the development of physiologic and anatomic lung abnormalities.

Animals↗
PubMed1986

Mannose-binding proteins isolated from rat liver contain carbohydrate-recognition domains linked to collagenous tails. Complete primary structures and homology with pulmonary surfactant apoprotein.

Preparations of mannose-binding protein isolated from rat liver contain two distinct but homologous polypeptides. The complete primary structures of both of these polypeptides have been determined by sequencing of peptides derived from the proteins, isolation and sequencing of cDNAs for both proteins, and partial characterization of the gene for one of the proteins. Each polypeptide consists of three regions: (a) an NH2-terminal segment of 18-19 amino acids which is rich in cysteine and appears to be involved in the formation of interchain disulfide bonds which stabilize dimeric and trimeric forms of the protein, (b) a collagen-like domain consisting of 18-20 repeats of the sequence Gly-X-Y and containing 4-hydroxyproline residues in several of the Y positions, and (c) a COOH-terminal carbohydrate-binding domain of 148-150 amino acids. The sequences of the COOH-terminal domains are highly homologous to the sequence of the COOH-terminal carbohydrate-recognition portion of the chicken liver receptor for N-acetylglucosamine-terminated glycoproteins and the rat liver asialoglycoprotein receptor. Each protein is preceded by a cleaved, NH2-terminal signal sequence, consistent with the finding that this protein is found in serum as well as in the liver. The entire structure of the mannose-binding proteins is homologous to dog pulmonary surfactant apoprotein.

Amino Acid Sequence↗
PubMed1986

Accumulation of [3H]sialyl-conjugates in sialidosis (sialidase-deficient) fibroblasts cultured in the presence of [3H]-N-acetylmannosamine.

Skin fibroblasts from normal individuals and a patient with the infantile form of sialidosis were cultured for up to 72 h in medium containing [3H]-N-acetylmannosamine. The sialidosis fibroblasts consistently accumulated more labeled compound(s) than the control cells, i.e. 37-88% more cpm per mg protein. Precipitation of sonicates of these cells with 10% trichloracetic acid, TCA, demonstrated that the excess radioactivity in the sialidosis fibroblasts was in one or more TCA soluble compounds. There was no detectable difference in the amount of label in the TCA insoluble material. The TCA soluble, labeled, material from the sialidosis and the control fibroblasts was separated, isolated and purified on AG1-X8, QAE Sephadex A-25 and Bio-Gel P-4 chromatography columns. Analysis of the isolated material showed the excess radioactivity in the sialidosis fibroblasts to be due to increased levels of [3H]sialic acid covalently bound to a variety of anionic sialyl conjugates. These compounds have been separated and partially purified. Finally, acid hydrolysis and chromatographic analysis of the TCA insoluble fractions showed that greater than 80% of the label in this material was also due to [3H]sialic acid. There was no detectable difference between the control and the sialidosis patient in the amount of label in this fraction.

Carbohydrate Metabolism, Inborn Errors↗
PubMed1986

Toxicity of toxaphene in the rat and beagle dog.

Residues of the insecticidal mixture, toxaphene, have been found in Great Lakes fish. The purpose of the present study was to assess the subchronic toxicity of toxaphene in the rat and beagle dog. In the rat study, groups of 10 male and 10 female animals were fed diets containing 0, 4, 20, 100, or 500 ppm of the test compound for 13 weeks. No clinical signs of toxicity or spontaneous deaths were observed. Toxaphene treatment up to 500 ppm had no effects on weight gain or food consumption. The liver/body weight ratio and hepatic microsomal enzyme activities (phenobarbital type) were increased in both sexes fed 500 ppm of the test compound. Toxaphene at the highest dose also caused kidney enlargement in male but not in female rats. Dose-dependent histological changes were seen in the kidney, thyroid, and liver. Changes in the liver and thyroid were considered to be adaptative but the injury in the proximal tubules of the kidney was focally severe. Groups of six male and six female beagle dogs were fed toxaphene in gelatin capsules at 0, 0.2, 2.0, and 5.0 mg/kg body wt/kg body wt/day for 13 weeks. Food consumption and growth rate were not affected. All animals survived the entire treatment period. No clinical signs of toxicity were observed. The liver/body weight ratio and serum alkaline phosphatase were increased in dogs of both sexes fed 5.0 mg/kg. Mild to moderate dose-dependent histological changes were observed in the liver and thyroid. Toxaphene was accumulated in a dose-dependent manner in the fat and liver of dogs and rats. Based on the biochemical, histological, and residue data, it was concluded that the no-adverse-effect levels of the pesticide were 4.0 ppm (0.35 mg/kg) for the rat and 0.2 mg/kg for the dog.

Animals↗
PubMed1984

Born before arrival. A study at the New Somerset Hospital, Cape Town.

A 3-month prospective study was undertaken to determine the factors which contribute to a baby being born before arrival (BBA) of the mother at hospital. The majority of the mothers of such babies were Black and lived in peri-urban areas of Cape Town. They were of higher parity, had experienced fewer complications during pregnancy, had shorter labours and had previously had more home deliveries than a comparative group of mothers. One-third of the babies were delivered in transit to hospital, and these babies had more major complications and a higher perinatal mortality rate than those born in hospital. The BBA rate of an area serves as an index of the accessibility of perinatal care. This index should be taken into account when reviewing and planning regional perinatal services. We believe that a BBA rate higher than 1,5% is unacceptable and merits investigation.

Adult↗
PubMed1983

EMG activity of the vastus medialis oblique and the vastus lateralis in their role in patellar alignment.

Using intramuscular electrodes the integrated electromyographic activity of the vastus medialis oblique and the vastus lateralis was examined in twenty normal females. The activity was recorded during the last thirty degrees of distal segment stabilized knee extension, when patellar subluxation commonly occurs. The electromyographic activity was normalized and expressed as a percentage of a maximal isometric contraction. Both muscles exhibited low levels of activity with no significant differences between the two. This study provides a quantitative method to assess whether muscular imbalance is present in patients with patellar subluxation.

Adult↗
PubMed1979

Effect of micropore filtration on pulmonary function after massive transfusion.

1. This study demonstrates a positive correlation between the number and size of infused microaggregates and the subsequent abnormality in pulmonary function as measured by oxygenation and dead space. 2. No such correlation between the severity of injury and the altered pulmonary function or transfusion volume was demonstrated. 3. We were unable to demonstrate an advantage to the use of a 40 mu micropore filter in preventing the adult respiratory distress syndrome (ARDS) or in improving pulmonary function in our patients. 4. One explanation for the failure to demonstrate such an advantage is the low efficiency of the filter used.

Adolescent↗