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Biomedical subjects

T Mann

Publications and source records attributed to T Mann.

At least 55 records · Page 3Linked to original sources
PubMed1990

Real-time ultrasound imaging for predicting ovine fetal age.

Fetal head width and thoracic depth were observed via real-time ultrasound imaging in 12 single-, 12 twin- and 4 triplet-bearing BooroolaxSouth Australian Merino ewes at weekly intervals during mid pregnancy. Fetal age varied by a maximum of 24 h. Relationships between fetal age and the linear measures (head width, thoracic depth) were determined within litter size categories, using both linear and quadratic terms. All relationships tested for linearity were statistically significant (P<0.05). A curvilinear relationship (P<0.05) was observed for fetal age and thoracic depth of twin fetuses. Significant (P<0.05) curvilinear relationships were also observed for fetal age and head width, and fetal age and thoracic depth when litter size data were pooled. We conclude that head width and thoracic depth are acceptable linear measurements for estimating fetal age in the ovine species. Implications of these results for research and for the commercial field are discussed.

Journal Article↗
PubMed1990

The impact of osteophytic and vascular calcifications on vertebral mineral density measurements in men.

To evaluate the influence of extravertebral calcification on spinal bone density determinations, we measured lumbar vertebral density in 71 hospitalized and 58 normal men using dual photon absorptiometry. The extent of vascular and osteophytic calcification was graded from lateral lumbar radiographs. Fifty-five (43%) of the subjects had identifiable osteophytes, and 86 (67%) had vascular calcifications. Despite similar ages and weights in subjects with and without ostephytes, those with osteophytes had greater spinal density (1.34 vs. 1.17 g/cm2; P less than 0.001), and there was a strong correlation between osteophyte severity and spinal density (r = 0.41; P less than 0.00001). Proximal femoral density was not different in those with and without osteophytes. The distribution of osteophytes in this population was not random, and as a result, the presence of osteophytes obscured the the relationship of bone density to age as well as the comparison of hospitalized to normal men. Vascular calcification had a minimal effect on vertebral density. In summary, osteophytic calcification exerted an important influence on the measurement of spinal bone density in men. This effect should be considered in both clinical and research applications of integral vertebral density measures.

Absorptiometry, Photon↗
PubMed1982

Passage of chemicals into human and animal semen: mechanisms and significance.

This review will begin with a brief account of the secretory mechanisms operating in the male reproductive tract. The entry of the different chemicals will be dealt with; with separate reference to testicular fluids, epididymal plasma, prostatic and vesicular secretions, and whole semen. Examples will be given of a number of chemical substances capable of passing into the secretions of the male reproductive tract and semen, in man and in animals--antispermatogenic and antiandrogenic agents, industrial chemicals, chemotherapeutic drugs, food additives, etc. The review will end with a critical appraisal of the methods involved and the results obtained from analyses of various chemicals in semen.

Adsorption↗
PubMed1981

Phosphoglycopeptide, a major constituent of the spermatophoric plasma of the octopus (Octopus dofleini martini).

A phosphoglycopeptide, accounting for approximately 90% of the characteristically high content of acid-soluble organically-bound phosphorus in the octopus spermatophoric plasma (4 mg P/ml), was identified. Electrophoretic and chromatographic purification, followed by chemical and enzymic hydrolysis, yielded D-galactose phosphate as a degradation product. The galactose and peptide moieties of the compound were linked via a phosphoryl rather than a glycosidic linkage but the peptide was devoid of aromatic amino acids.

Amino Acids↗
PubMed1980

Hemodynamic effects of nitrous oxide administered during cardiac catheterization.

To assess the effects of nitrous oxide on hemodynamics and left ventricular function in man, 30 patients (24 of whom had coronary artery disease) were studied at the time of cardiac catheterization. Left ventricular peak-systolic pressure and end-diastolic volume showed no significant change during nitrous oxide inhalation. The maximum rate of pressure rise declined slightly, but left ventricular end-diastolic pressure and ejection fraction were unchanged. Heart rate and cardiac index declined modestly. The pressure-rate product and left ventricular minute work index decreased, suggesting a decline in myocardial oxygen requirements. These data suggest that nitrous oxide inhalation does not produce important depression of left ventricular performance. The consistent decrease in the determinants of myocardial oxygen demand suggests that use of this analgesic agent may be helpful in patients with coronary heart disease.

Adolescent↗
PubMed1980

Refractory ergonovine-induced coronary vasospasm: importance of intracoronary nitroglycerin.

Recent experience has suggested that the ergonovine maleate test is a safe procedure for the diagnosis of variant angina pectoris, because ergonovine-induced coronary vasospasm has generally been reversible by sublingual nitroglycerin. This report describes five cases of ergonovine-induced coronary vasospasm that were refractory to sublingual nitroglycerin. Four of these patients had cardiac arrest. In two patients the vasospasm was responsive to intracoronary nitroglycerin administration. Three patients died as a reuslt of the test. The two survivors differed from the nonsurvivors in the total dose or ergonovine given (0.1 and 0.15 mg versus 0.17, 0.3 and 0.3 mg, respectively) and in the method of administration of ergonovine. The survivors were given serial doses of 0.05 mg each whereas the three nonsurvivors received either larger initial doses (0.1 followed by 0.07 mg) or progressive incremental doses (0.05, 0.1 and 0.15 mg serially). Sublingual nitroglycerin, given to all five patients, and intravenous nitroglycerin, given to three of the five, were ineffective in reversing vasospasm. Intracoronary nitroglycerin favorably altered the course of the survivors. Thus, the ergonovine maleate test is not benign and may cause severe coronary vasospasm that is unresponsive to sublingual and intravenous nitroglycerin, but may be reversed by intracoronary nitroglycerin.

Administration, Oral↗
PubMed1980

Aarskog's syndrome.

Six children with Aarskoga's facial-digital-genital syndrome are described, and the genetics of the condition discussed. We suggest that this anomaly may be fairly common and that a syndrome identification centre could lead to earlier diagnosis of children with this and other syndromes.

Child↗
PubMed1979

Peroxidative breakdown of phospholipids in human spermatozoa, spermicidal properties of fatty acid peroxides, and protective action of seminal plasma.

Aerobic incubation of human spermatozoa in the presence of catalytic amounts of ascorbate and ferrous ion results in rapid peroxidative breakdown of sperm phospholipids and fatty acids; most strongly affected are phosphatidyl ethanolamine, ethanolamine plasmalogen, and docosahexanoic acid. Both peroxidation of the endogenous sperm phospholipid and the concurrent loss of motility can be fully prevented, but not reversed, by an "antiperoxidant" factor present in human seminal plasma. Exogenously applied lipid peroxides are powerfully spermicidal. Washed human spermatozoa, at a concentration normally present in semen, treated with as little as 30 nmoles of lipid peroxide/ml become irreversibly immotile within a few minutes. The antiperoxidant factor present in human seminal plasma effectively counteracts the toxic effect of exogenous peroxidized fatty acids upon human spermatozoa, but is unable to restore motility lost by lipid peroxide action.

Chemical Phenomena↗
PubMed1979

Factors contributing to altered left ventricular diastolic properties during angina pectoris.

Mechanisms involved in the altered left ventricular (LV) diastolic properties during angina were studied in 26 patients with coronary artery disease. Angina was induced by rapid atrial pacing and measurements were made at rest and during angina in the immediate post-pacing period. No changes occurred in heart rate (71 +/- 3 to 73 +/- 3 beats/min, NS) or right ventricular (RV) end-diastolic pressure (10 +/- 1 to 11 +/- 1 mm Hg, NS), while significant increases occurred in LV end-diastolic pressure (17 +/- 1 to 30 +/- 1 mm Hg, p less than 0.01), aortic diastolic pressure (74 +/- 3 to 80 +/- 3 mm Hg, p less than 0.01), coronary sinus blood flow (133 +/- 15 to 212 +/- 32 ml/min, p less than 0.01), and the time constant (T) of LV pressure fall in early diastole (43 +/- 2 to 58 +/- 4 msec, p less than 0.01). Despite the rise in arterial pressure, a significant fall was observed in peak negative dP/dt (1961 +/- 106 to 1751 +/- 80 mm Hg/sec, p less than 0.01). Changes in RV end-diastolic pressure do not explain the increased LV end-diastolic pressure during angina. Increased aortic pressure and coronary blood flow may contribute, but the simultaneous fall in peak negative dP/dt and rise in T suggest that impaired ventricular relaxation is an important factor contributing to the previously demonstrated alteration in LV diastolic properties during angina pectoris.

Angina Pectoris↗
PubMed1978

Effusive-constrictive hemodynamic pattern due to neoplastic involvement of the pericardium.

Eight patients with metastatic malignancy of the pericardium who demonstrated the hemodynamics of subacute effusive-constrictive pericarditis were studied. All patients had clinical evidence of cardiac tamponade due to malignant pericardial effusion and were referred for therapeutic pericardiocentesis. In six in whom pericardiocentesis was successfully performed, right atrial pressure remained elevated after pericardiocentesis and return of the intrapericardial pressure to zero; in these patients, hemodynamic data were initially compatible with tamponade but suggested constriction after removal of the pericardial fluid. In the remaining two patients, echocardiography revealed pericardial fluid, but attempted pericardiocentesis was unsuccessful. In these two patients, the hemodynamic data suggested pericardial constriction; subsequent pathologic examination revealed neoplastic involvement of the visceral pericardium. Thus, subacute effusive-constrictive pericarditis, previously recognized as a complication of tuberculosis or mediastinal radiation, may also be due to metastatic malignancy. The syndrome can readily be demonstrated when right heart catheterization is performed in conjunction with pericardiocentesis.

Cardiac Tamponade↗
PubMed1978

Effect of nitroprusside on regional myocardial blood flow in coronary artery disease. Results in 25 patients and comparison with nitroglycerin.

The effect of nitroprusside on regional myocardial specific blood flow (RMBF) was evaluated in 25 patients with the xenon-133 washout technique. Six patients were normal (group 1), six patients had coronary artery disease without collateral vessels (group 2), and thirteen patients had coronary artery disease with collateral vessels (group 3). In group 1, RMBF was unchanged following nitroprusside. RMBF decreased significantly in both group 2 and group 3, including seven patients in group 3 with high-grade collateral vessels. The results were compared to the effect of nitroglycerin in 31 patients previously studied using the same technique. Mean arterial pressure and pressure-rate product were comparably reduced by both drugs. In contrast to the findings with nitroprusside, after sublingual nitroglycerin RMBF decreased markedly in normals and increased in patients with coronary artery disease and high-grade collaterals. The data suggest that nitroprusside may primarily affect resistance vessels within the coronary circulation, as opposed to the effect of nitroglycerin on conductance vessels. Thus, nitroprusside could result in redistribution of blood flow away from ischemic areas and potentially increase ischemic injury in some patients with coronary artery disease.

Blood Pressure↗