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Biomedical subjects

C D Morris

Publications and source records attributed to C D Morris.

At least 91 records · Page 5Linked to original sources
PubMed1990

Calcium regulating hormones in essential hypertension. Importance of gender.

Alterations of calcium metabolism have been described in human essential hypertension and experimental hypertension. We investigated the interrelationship of parathyroid hormone (PTH) and 1,25(OH)2-vitamin D (1,25(OH)2D) in patients with untreated essential hypertension as compared to normotensive controls. The hypertensive subjects (n = 75; 43 men, 32 women) had a mean blood pressure of 138 +/- 8/95 +/- 5 mm Hg as compared with 120 +/- 11/80 +/- 8 in the normotensive group (n = 40; 22 men, 18 women). Serum PTH was measured with an intact molecule immunochemiluminometric assay and 1,25(OH)2D was measured with radioimmunoassay after HPLC separation. Hypertensive men had PTH levels that were 36% higher than normotensive men (5.3 +/- 2.9 v 3.9 +/- 0.8 pmol/L, P = .005). When blood pressure was analyzed as a continuous variable, there was a direct correlation between it and serum PTH in men (r = .31, P = .004). In women, by contrast, there was no difference in serum PTH between hypertensive and normotensive subjects and no relationship between blood pressure and the serum PTH concentration. Blood pressure was inversely correlated with serum phosphorus levels in both sexes (r = -0.20, P = .04). In men, the elevated serum PTH levels and depressed serum phosphorus levels would have predicted that serum 1,25(OH)2D would be higher in the hypertensive subjects. However, that was not observed, as serum 1,25(OH)2D was slightly lower in hypertensive (38.3 +/- 15.2 pg/mL) than normotensive men (42.7 +/- 11.3, P = .21).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Bone mineral density in spontaneous hypertension: differential effects of dietary calcium and sodium.

Dietary calcium and sodium have been postulated to modify both bone mineral status and blood pressure regulation in humans and animals. The spontaneously hypertensive rat (SHR) manifests several defects in calcium metabolism that may contribute to its hypertension. Blood pressure and bone mineral status were measured in SHR and normotensive Wistar-Kyoto rats (WKY) as a marker of whole animal calcium metabolism. In addition, the effect of alterations in dietary calcium and sodium on bone status were examined. At 6 weeks of age, seven male SHR and seven male WKY were placed on a control diet. At the same age, 28 SHR and 28 WKY were randomized to four diets containing either 2.0% or 0.1% calcium and 1.0% or 0.25% sodium. Four markers of bone mineral status were analyzed: bone density measured by direct photon absorptiometry, and total bone calcium, phosphorus, and magnesium content measured by atomic absorption spectrophotometry. The SHR exhibited significantly lower levels (p less than 0.001) of bone density and bone magnesium content than the WKY, whereas bone phosphorus and calcium did not differ between the two strains. The 2.0% calcium diets resulted in increased bone density and bone calcium content, and lower bone magnesium in both strains. The 1.0% sodium diets were associated with decreased bone density in the SHR, but not in the WKY. These findings identify another indicator of disturbed calcium metabolism in the SHR that may be related to impaired renal calcium handling. They are consistent with previously reported reductions in renal calcium reabsorption and decreased intestinal calcium transport in older SHR.

Animals↗
PubMed1990

Parity, fecundity and body size of Mansonia dyari in Florida.

Seasonal trends in reproductive performance and size were examined among female Mansonia dyari. The incidence of parity ranged between 6.9 and 58.1% and averaged 22.5% during an 8-month interval, with 4 peaks in parous rate believed to follow periods of emergence. Parous rates were positively correlated with wing lengths, indicating size-dependent survivorship. Wing lengths were highest in the winter and early spring, decreased to a minimum at the end of summer, and increased in the autumn, showing negative correlations with ambient temperatures recorded prior to adult capture. Female biomasses and fecundities were positively correlated with wing lengths, and their mean values varied significantly among sample dates. Egg development in Ma. dyari was completed by 5.4 days post blood meal at 26 degrees C and 7.6 days at 20 degrees C. No evidence for autogeny was observed.

Animals↗
PubMed1990

Distribution and abundance of larval Coquillettidia perturbans in a Florida freshwater marsh.

All instars of larval Coquillettidia perturbans were found in the same habitats, but early instar larvae were more aggregated than later instars. Larvae were most numerous in areas dominated by arrow-arum (Peltandra virginica) and maidencane (Panicum hemitomon), less so in areas dominated by sedges (Carex spp.) and miscellaneous mixed vegetation, and least abundant in pickerelweed (Pontederia cordata) areas. Larvae were uncommon in open water or in areas dominated by small floating plants such as water fern (Salvinia rotundifolia), duckweekd (Lemna minor) and mosquito fern (Azolla caroliniana). Larval concentrations were greatest in water 35-70 cm deep. There was also a tendency for them to concentrate in areas beyond 25 m from shore. Larvae were log-normally distributed in favorable sites and became progressively more aggregated as sites became less favorable.

Animals↗
PubMed1990

Evaluation of 1-octen-3-ol as an attractant for Coquillettidia perturbans, Mansonia spp. and Culex spp. associated with phosphate mining operations.

Field studies were conducted in phosphate mined areas of Polk County, FL, to determine the responses of mosquitoes produced as a result of mining operations to octenol and carbon dioxide. There was a highly significant response of all species except Culex erraticus and Anopheles quadrimaculatus to CO2. Also, a significant negative octenol response was shown for An. quadrimaculatus. Coquillettidia perturbans, Mansonia titillans and Cx. salinarius had an increased response to octenol relative to no attractant. There was a slightly negative interactive effect between octenol and 500 cc/min CO2 for Anopheles spp. and Culex (Melanoconion) spp. Both Cq. perturbans and Ma. titillans showed a significant synergistic enhancement in catch with octenol supplemented CO2 when compared with CO2 alone. However, their response to CO2 was not significantly different at 2 release rates (200 and 500 cc/min). There was a slightly greater than additive effect for the combination of octenol and CO2 for Cx. nigripalpus.

Animals↗
PubMed1990

Hypoplastic left heart syndrome: natural history in a geographically defined population.

Advances in surgical treatment of hypoplastic left heart syndrome with the Norwood procedure and cardiac transplantation have made essential the understanding of the natural history of hypoplastic left heart syndrome. In a geographically defined population, we ascertained the prevalence of hypoplastic left heart syndrome in children born in Oregon from 1971 through 1986. Clinical and anatomic data were extracted from the charts of the 98 affected children and the survival rate was calculated. Hypoplastic left heart syndrome occurred in 0.162 per 1000 live births in Oregon during this period. No syndrome complex was prevalent and 84% were free of other congenital malformations. However, there was an increased occurrence of congenital heart defects in first-degree relatives of probands with hypoplastic left heart syndrome. Of the affected children 15 +/- 4% died on the first day of life, 70 +/- 5% died within the first week, and 91 +/- 3% died within 30 days. No secular change in survival occurred during the study. Palliation with the Norwood procedure was performed in 20 children. Although survival was significantly improved with this surgery (P = .01), the effect was observed principally through 30 days of life and only one of these children remains alive. Hypoplastic left heart syndrome is a lethal congenital heart defect in children and poses management and ethical dilemmas.

Abnormalities, Multiple↗
PubMed1989

Disease profiles for white and black adult and geriatric patients. An analysis of 2,008 hospital medical admissions.

A prospective analysis of 2,008 discharge diagnoses revealed important differences in disease incidence between black and white adult and geriatric patients treated in the Department of Medicine, Frere Hospital, East London. Among geriatric patients the major differences were the increased incidences among blacks of tuberculosis, pulmonary circulatory disorders and cardiomyopathy, as opposed to ischaemic heart disease, cerebrovascular disorders and chronic obstructive pulmonary disease among whites. Among blacks hypertension was less common than had been expected and occurred predominantly in females. Tuberculosis affected 14% of blacks but only 1.6% of whites. It was also the commonest cause of medical deaths and responsible for 31% of deaths of black patients. Analysis of age patterns showed that 68% of whites and 31% of blacks were over 60 years old; 18% of whites and 3% of blacks were over 80 years old. These figures indicate the need to extend hospital facilities for geriatric patients, and for more comprehensive training in geriatric medicine for doctors and nurses.

Adult↗
PubMed1989

Lovastatin in the treatment of multifactorial hyperlipidemia associated with proteinuria.

The efficacy and safety of lovastatin as a hypolipidemic agent were evaluated in ten adult patients with secondary hypercholesterolemia due to proteinuria (greater than 2 g/d) and (in seven patients) concurrent corticosteroid therapy. Patients were on a low-cholesterol diet throughout the study. After a 4-week baseline period, patients were randomized to receive either placebo or 10 mg lovastatin twice daily for a period of 6 weeks. The dose of lovastatin was increased to 20 mg twice daily for 6 weeks, and 40 mg twice daily for 6 weeks in the latter group. Those patients who received placebo for the first 6 weeks subsequently received 10, 20, and 40 mg of lovastatin twice daily in a stepped dose regimen, with each dose given for 6 weeks. Lovastatin was well tolerated by all patients and none withdrew from the study. Baseline plasma cholesterol concentrations (390 +/- 20 mg/dL; mean +/- SEM) decreased 22% (P less than 0.003) at the lowest dose of 10 mg twice daily, 27% at 20 mg twice daily, and 33% at 40 mg twice daily. Baseline plasma triglycerides decreased by 25% (P less than 0.05) at the highest dosage. Concentrations of low-density lipoprotein (LDL) cholesterol fell by 29%, 34%, and 45% on doses of 10, 20, and 40 mg of lovastatin twice daily. Concentrations of high-density lipoprotein (HDL) cholesterol increased slightly. Serum creatinine concentrations and proteinuria were not affected by lovastatin therapy. We conclude that lovastatin was a well-tolerated and extremely effective hypocholesterolemic agent in patients with persistent secondary hypercholesterolemia associated with proteinuria or proteinuria and concurrent corticosteroid therapy.

Adrenal Cortex Hormones↗
PubMed1989

The effect of dietary interventions to reduce blood pressure in normal humans.

Changes in electrolyte intake have been advocated to lower the prevalence of hypertension in the normal population. To elucidate the potential impact of such strategies, we conducted a comprehensive analysis of data from three interventions, namely, salt (NaCl) restriction, calcium (Ca) supplementation, and potassium (K) supplementation in normal volunteers. Eighty-two adults lowered their Na intake from 157 +/- 6 S.E. to 68 +/- 3 mEq/day for 12 weeks. Population mean systolic and diastolic blood pressure decreased less than or equal to 2 mm Hg. Ca supplementation, 1.5 g daily for 12 weeks in 37 men, decreased blood pressure compared to 38 men receiving placebo. Ca supplementation, 1 g daily for 8 weeks in an older group of 44 normal subjects, decreased supine diastolic and standing systolic blood pressure. K supplementation with a nonchloride salt in 64 normal adults for 4 weeks had no effect on systolic or diastolic blood pressure even though urinary excretion was increased by 20 mmol/day. The responses to all interventions were Gaussian in distribution. A potentially adverse effect on blood pressure in some normal individuals cannot be excluded on the basis of the currently available data. Although all three interventions may benefit some hypertensive and some normal individuals, the data from these relatively short-term cross-sectional studies are insufficient to warrant generalized dietary recommendations for the normal population.

Adult↗
PubMed1989

Production and maintenance of large numbers of Dugesia tigrina (Turbellaria: Tricladida) for the control of mosquitoes in the field.

Methods to increase and preserve Dugesia tigrina for mosquito control purposes through cocoon production, mechanical sectioning and cold storage were examined. Cocoon production was an ineffective and unreliable means of increasing planarian numbers, with an average of only 0.19 cocoons containing 0.74 young produced per adult per week. In comparison, mechanical sectioning proved to be more appropriate for increasing the number of planaria. One hundred planaria averaging 8 mm in length could be sectioned into 600 segments in approximately 18 min; regeneration was achieved by approximately 94% of these segments, usually within 8 days after sectioning. Techniques were developed to store planaria at 10 degrees C until needed for field release.

Animals↗
PubMed1989

Significant associations between mosquito control service requests and mosquito populations.

Correlation and multiple regression analyses were used to examine the relationships between mosquito population densities and the numbers of telephone requests for mosquito control services made by people in Polk County, Florida. In 32 of 42 census tracts, there were significant (P less than 0.05) correlations between mosquitoes and requests and that, for 16 tracts, a significant linear relationship could be demonstrated between service requests and only one mosquito taxon. The significant associations were dependent on the types of mosquitoes rather than the relative abundance among mosquito groups. Service requests were most often related to Aedes, followed in importance by Culex salinarius and Anopheles; least often to Cx. nigripalpus. Evidence to support a cause and effect relationship is also presented.

Aedes↗
PubMed1989

The radiography, haematology and biochemistry of pulmonary tuberculosis in the aged.

Ninety-three elderly patients with pulmonary tuberculosis were surveyed prospectively to determine the extent and severity of radiological, haematological and biochemical abnormalities. Radiological features of inflammatory changes were present in all patients; 7 per cent of these were purely apical, 48 per cent were in mid and basal zones and in 46 per cent there was a mixed picture. Cavities were seen in 33 per cent of radiographs; half of these occurred in the apical and half in the mid and basal zones. A pleural reaction was present in 46 per cent of cases. Hilar gland enlargement was not seen. Thus radiographs 'atypical' for pulmonary tuberculosis were usual with the major changes being basal and peripheral. Haematological abnormalities were normochromic normocytic anaemia (66 per cent), neutrophilia (69 per cent), thrombocytosis (33 per cent), rapid erythrocyte sedimentation rate (90 per cent), and lymphocytopenia and monocytosis in 22 and 28 per cent respectively. Biochemical abnormalities were hyponatraemia (60 per cent), hypokalaemia (42 per cent), hypoalbuminaemia (83 per cent), and (before treatment) elevation of bilirubin (20 per cent), alkaline phosphatase (62 per cent), aspartic transaminase (77 per cent) and lactic dehydrogenase (74 per cent). The abnormal liver function tests may reflect unsuspected extrapulmonary disease. Radiologically mild opacification occurring frequently in the lower zones and associated with a pleural reaction in half of cases is compatible with tuberculosis. The unexplained presence of any of these haematological and biochemical abnormalities should raise suspicion of the disease.

Aged↗
PubMed1989

The haematological and biochemical changes in severe pulmonary tuberculosis.

This study surveys the extent and severity of haematological and biochemical abnormalities which occurred in 265 patients with pulmonary tuberculosis, and records the haematological changes that occur with treatment. Anaemia was present in 60 per cent of patients, more frequently in males than in females. Leucocytosis with neutrophilia occurred in 40 per cent, lymphopenia in 17 per cent and monocytopenia in 50 per cent. Platelet count and erythrocyte sedimentation rate were elevated in 52 and 80 per cent respectively. Bone marrow aspiration and trephine biopsy were of limited diagnostic value. Ferritin and vitamin B12 levels were increased in 94 and 57 per cent of subjects respectively whilst serum and red cell folic acid were within normal limits in 83 per cent. The frequency of the important biochemical changes were hyponatraemia (43 per cent) and hypoalbuminaemia (72 per cent); alkaline phosphatase, aspartic transaminase and lactic dehydrogenase levels were elevated in approximately a third of patients possibly due to unsuspected dissemination. There was a close correlation between the acid-fast bacilli in sputum and abnormal values, particularly those of body weight, haemoglobin, platelet count, white cell count and erythrocyte sedimentation rate. Failure of these indices to return to normal was invariably associated with persistent excretion of acid-fast bacilli. We have shown that haematological and biochemical abnormalities in pulmonary tuberculosis are common and may be valuable aids to diagnosis. Some haematological markers also reflect response to treatment.

Adult↗
PubMed1988

Epidemic of pulmonary tuberculosis in geriatric homes.

The prevalence of pulmonary tuberculosis in 809 residents of 11 old-age homes for whites and 1 for coloureds in East London, CP, was investigated in a cross-sectional study. A Mantoux test, chest radiography, an enzyme-linked immunosorbent assay (ELISA) and sputum culture were used. The diagnosis was made on sputum culture in 12 subjects. The Mantoux test was positive in 7 of these subjects, and in 25% of the population. The ELISA on adsorbed sonicated mycobacterial antigen had a positive predictive value of 13% and probably has no diagnostic value for tubercular disease in this population. Of the subjects with a positive diagnosis 1 had a normal chest radiograph; 10 had minimal basal inflammatory infiltrates or patchy fibrotic changes, and 1 had evidence of classic reactivation of old apical lesions. The national incidence of tuberculosis in the low-risk white population is 16/100,000. In old-age homes for whites, however, the overall case rate was 798/100,000 (a 50-fold increase), and in one home where there was a cluster of cases, it was 6,849/100,000. In the home for coloureds the prevalence was 10,344/100,000. This confirms other studies showing that elderly people living in old-age homes are at particular risk of developing tuberculosis. Males appear to be at higher risk than females. Recommendations regarding the diagnosis and control of tuberculosis in the elderly in institutions and in old-age homes are made.

Aged↗