Search PubMed⌕ Search

Biomedical subjects

L S Smith

Publications and source records attributed to L S Smith.

At least 73 records · Page 4Linked to original sources
PubMed1985

The epidemiology of drowning in Cape Town--1980-1983.

The results of a 4-year retrospective study on the epidemiology of drowning in greater Cape Town are presented. With rates corrected to per 100 000 population, the highest incidences of drowning were found to be in white children and adult black males. The commonest sites of drowning were the coastline and harbours of greater Cape Town. The majority of adult drownings were associated with positive blood alcohol tests (64,6%) and in the case of black men occurred while at work. The majority of drownings in children occurred in home swimming pools.

Accidents↗
PubMed1985

Noninvasive detection and monitoring of regional myocardial ischemia in situ using depth-resolved 31P NMR spectroscopy.

Phosphorus (31P) NMR spectra showing the relative concentrations of phosphocreatine, ATP, and Pi were recorded noninvasively from localized regions in the left ventricles of dog hearts in situ by using depth-resolved surface-coil spectroscopy at 1.5 T. Proton (1H) NMR surface-coil imaging was used to position 31P NMR coils and to determine the location of depth-resolved volumes immediately prior to 31P examination. Occlusion of the left anterior descending coronary artery produced regional ischemia detected as changes in the ratios of phosphocreatine, ATP, and Pi and by changes in the pH measured from the spectra. Spectral changes were not typically observed in regions adjacent to ischemic myocardium. Reperfusion produced some recovery, and ventricular fibrillation resulted in deterioration in high-energy metabolites. The location and size of ischemic tissue was measured by single-photon-emission computed tomography (SPECT) and gamma-ray counting or by staining excised hearts. The technique should permit the long-term noninvasive monitoring of the metabolic response of the heart to pathologic processes and allow assessment of interventions.

Adenosine Triphosphate↗
PubMed1985

Comparison of forceps used for transbronchial lung biopsy. Bigger may not be better.

Transbronchial lung biopsy is a useful procedure to obtain an alveolar specimen in the evaluation of diffuse lung infiltrates. Large forceps (cup and alligator) are expected to result in larger specimens and improve diagnostic yield. We performed transbronchial lung biopsy in 20 patients using two different sized forceps in each patient. We compared the histology and histopathologic diagnoses obtained by small cup forceps, large cup forceps, and large alligator forceps. Small and large cup forceps provided equally good results; however, the large open end of the alligator forceps often prevented distal passage through narrowing airways, engaging proximal bifurcating bronchial wall and cartilage rather than lung parenchyma. Small and large cup forceps are more likely to obtain the desired alveolar specimen.

Biopsy↗
PubMed1984

Changes in carbonic anhydrase activity in coho salmon smolts resulting from physical training and transfer into seawater.

Carbonic anhydrase (CA) activity was measured in blood and in gill tissue of coho salmon smolts during chronic exercise and subsequent transfer into seawater. The mean level of CA activity was higher in blood than gill tissue in both freshwater and seawater. CA activity in gill tissue increased significantly after the smolts had adapted to seawater. CA activity in blood decreased significantly in the group of fish given the highest exercise level after they had adapted to seawater. There were no significant differences in CA activity in gill tissue between control and exercise groups in either freshwater or seawater.

Acclimatization↗
PubMed1984

Anatomy and metabolism of the normal human brain studied by magnetic resonance at 1.5 Tesla.

Proton magnetic resonance (MR) images were obtained of the human head in magnetic fields as high as 1.5 Tesla (T) using slotted resonator high radio-frequency (RF) detection coils. The images showed no RF field penetration problems and exhibited an 11 (+/- 1)-fold improvement in signal-to-noise ratio over a .12-T imaging system. The first localized phosphorus 31, carbon 13, and proton MR chemical shift spectra recorded with surface coils from the head and body in the same instrument showed relative concentrations of phosphorus metabolites, triglycerides, and, when correlated with proton images, negligible lipid (-CH2-) signal from brain tissue on the time scale of the imaging experiment. Sugar phosphate and phosphodiester concentrations were significantly elevated in the head compared with muscle. This method should allow the combined assessment of anatomy, metabolism, and biochemistry in both the normal and diseased brain.

Brain↗
PubMed1984

Rounded atelectasis due to acute exudative effusion. Spontaneous resolution.

Rounded atelectasis is an interesting roentgenographic entity that must be distinguished from intrathoracic neoplasm. Chronic pleural disease, particularly that due to asbestos exposure, is a frequently cited cause, and is considered to be a sine qua non by some. We report a case of rounded atelectasis with an acute parapneumonic exudative effusion that resolved spontaneously with roentgenographically normal pleura.

Humans↗
PubMed1984

Assessment and management of vaginitis and cervicitis.

This article presents the assessment, management, client education, and psychosocial considerations related to trichomoniasis, candidiasis, Gardnerella vaginitis, and cervicitis due to Chlamydia trachomatis and Neisseria gonorrhea. The physiology of the vagina, approach to the history and physical exam, specimen collection, and laboratory diagnosis are included. Recommended treatment regimens and preventive behaviors are discussed in detail. The psychosocial impact to the client of having a discharge which may be a sexually transmitted disease is discussed.

Anti-Bacterial Agents↗
PubMed1983

Signal, noise, and contrast in nuclear magnetic resonance (NMR) imaging.

Calculations of the sensitivity of the saturation recovery and inversion recovery pulse sequences used in nuclear magnetic resonance imaging show the former to be superior in discriminating between tissues with the same proton density but different T1's. Two other pulse sequences, which are combinations of the above, have also been analyzed. These have lower T1 discrimination sensitivity, but other considerations, such as self-normalization, may still make them attractive. The calculations are only valid for selective excitation pulse sequences in which the selected slice profiles are approximately rectangular, and thus a sin(bt)/t radiofrequency excitation is desirable. In order to ensure that the saturation recovery sequence gives valid results for pulse repetition times comparable to or shorter than T2, it is necessary to destroy the coherence between pulse applications. For this purpose we use a series of "spoiler" gradient pulses between pulse trains. The saturation recovery pulse sequence also has the advantage that, by the correct choice of interpulse spacing, sensitivity close to the optimum T1 discrimination can be achieved over a wide range of T1 values. This has the potential advantage to the clinician of simplifying his choice of parameters for imaging.

Humans↗
PubMed1983

Nuclear magnetic resonance imaging: contrast-to-noise ratio as a function of strength of magnetic field.

The choice of the strength of the magnetic field for an imaging system based on the nuclear magnetic resonance of hydrogen is considered. It is shown by an analysis based on in vitro data that the quality, or contrast-to-noise ratio, of images based on T1 or T2 discrimination increases with field up to 1.5-2 T. After a brief discussion of potential high-field limitations, results are presented which show that images of the human head with excellent anatomic detail can be produced at 1.5 T or 64 MHz.

Magnetic Resonance Spectroscopy↗
PubMed1982

Medical, legal and administrative aspects of cadaveric organ donation in the RSA.

A shortage of donors remains the major limiting factor as regards the number of kidney and heart transplants performed in South Africa each year. The medical, legal and administrative aspects of cadaveric organ donation in this country are reviewed. The pathophysiology of brain death and the criteria necessary for a definite diagnosis are described, together with the criteria for the selection of cadaveric organ donors. The statutory requirements pertaining to the removal of human hearts and kidneys for the purposes of transplantation are detailed. The subsequent management of the brain-dead donor up to the time of excision of the required organ is described, and a note regarding the preservation and transportation of the donor organs is added.

Age Factors↗
PubMed1982

Alcohol and drowning in Cape Town. A preliminary report.

The literature on alcohol and drowning is reviewed, and the possible mechanisms of action of alcohol in drowning discussed. A 3-year enquiry into the role of alcohol in drowning in greater Cape Town shows that a large percentage of adult victims of drowning were under the influence of alcohol at the time. Recommendations are made to increase public awareness of the hazards related to the consumption of alcohol while engaging in aquatic activity.

Adolescent↗
PubMed1982

Creatine phosphokinase activities in rainbow trout, Salmo gairdneri, associated with rapid decompression.

Serum creatine phosphokinase (CPK) activity levels were monitored in rainbow trout following rapid decompression. Serum activity was elevated 8.5-fold at 24 h and 15-fold at 48 h after decompression from 100-feet sea water (fsw) dives of 1 1/2 h duration. Serum enzyme activity was unchanged in the 66-fsw group. Stress results indicated a proportional relationship exists between serum CPK activity and muscular activity. CPK activities were found to be 1,023 in skeletal (white) muscle and 255 mumol . min-1 . g-1 in heart ventricle. Elevated CPK activity was not associated with tissue necrosis and is considered a consequence of increased anaerobic respiration stimulated by muscular activity and pressure-induced peripheral hypoxia.

Animals↗