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Biomedical subjects

S Fraser

Publications and source records attributed to S Fraser.

At least 19 recordsLinked to original sources
PubMed1992

Medical audit of hysterectomy in the Hunter Area of New South Wales.

A computer search in the New South Wales (NSW) Department of Health statistical data base was made to obtain the medical record numbers of patients who had had hysterectomies in the public or private hospitals of the Hunter Area of the State during the years 1987-89. The medical records of patients so identified were then extracted and reviewed by a medical team. The age at and the principal indication for hysterectomy were noted in each case and these data were then compared with those for the rest of NSW. The hysterectomy rate in the Hunter Area was 66.5 per 10,000 women aged 15 years or more, compared with a rate of 33.8 per 10,000 in the rest of NSW. When the 9.04% of hysterectomies performed on patients whose domicile was outside the Hunter Area were excluded, the corrected hysterectomy rate for the area was 57.46 per 10,000 women. The commonest indications for hysterectomy were menorrhagia (25.4%) and fibroids (15.32%). The limitations of this kind of retrospective study are discussed and suggestions are made for an improved methodology to be used in a future study.

Adolescent↗
PubMed1991

Comparison of the Clearview Chlamydia test, Chlamydiazyme, and cell culture for detection of Chlamydia trachomatis in women with a low prevalence of infection.

Two antigen detection systems, Clearview Chlamydia (Unipath Ltd., Bedford, United Kingdom) and Chlamydiazyme (Abbott Laboratories, North Chicago, Ill.), were compared with culture for the diagnosis of chlamydia infection in women attending gynecological clinics. Chlamydia trachomatis was isolated from 43 (4.5%) of the 965 women tested. In comparison with tissue culture, the Clearview Chlamydia and Chlamydiazyme tests had sensitivities of 79.0 and 74.4%, respectively, and both had a specificity of 99.6%. The results show that the Clearview Chlamydia test is comparable to Chlamydiazyme for the detection of C. trachomatis from endocervical specimens in a population with a low prevalence of infection.

Adolescent↗
PubMed1990

Segmentation in the chick embryo hindbrain is defined by cell lineage restrictions.

In the chick embryo hindbrain, morphological segmentation into rhombomeres is matched by metameric patterns of early neuronal differentiation and axonogenesis. Boundaries between rhombomeres coincide with boundaries of expression of murine regulatory genes. By clonal analysis using intracellular marking, we show here that the rhombomere boundaries are partitions across which cells do not move. When a parent cell is marked before the appearance of rhombomere boundaries, the resulting clone is able to spread into the neighbouring rhombomere. When marked after boundary appearance, the clone still expands freely within the rhombomere of origin, but it is now restricted at the boundaries. Rhombomeres in the chick embryo thus behave like polyclonal units, raising the possibility that they are analogous to the compartments of insects.

Animals↗
PubMed1990

Residence time distributions of solutes in the perfused rat liver using a dispersion model of hepatic elimination: 1. Effect of changes in perfusate flow and albumin concentration on sucrose and taurocholate.

The residence time distributions of sucrose and taurocholate have been determined from the outflow concentration-time profiles after bolus input into an in situ perfused rat liver preparation. The normalized variance (and the dispersion number) appeared to be independent of perfusate flow rate (10 to 37 ml/min) and perfusate albumin concentration (0.5%). The apparent volume of distribution for sucrose appeared to increase with flow rate but was unaffected by the concentration of albumin (0-5%) present in the perfusate. The changes in taurocholate availability with flow rate were adequately accounted for by the dispersion model, whereas taurocholate availability-protein binding changes required an albumin-mediated transport model to be used in conjunction with the dispersion model.

Albumins↗
PubMed1990

Residence time distributions of solutes in the perfused rat liver using a dispersion model of hepatic elimination: 2. Effect of pharmacological agents, retrograde perfusions, and enzyme inhibition on evans blue, sucrose, water, and taurocholate.

The effect of altered physiological conditions on the residence time distributions of sucrose, water, and taurocholate in the rat liver were studied using a bolus injection and quantifying fraction of total outflow per ml-time profiles. Retrograde perfusions increased the residence times of sucrose and water markedly and were associated with very low hepatic availabilities for taurocholate. Resistance by the inlet sinusoids sphincters, which become outlet sphincters during retrograde perfusions, is suggested as the explanation for the observation. Infusions of noradrenaline, propranolol, and lidocaine resulted in relatively small changes in the mean residence times for sucrose and water with no apparent relationship existing between the efficiency number of taurocholate and volumes of either water or sucrose. Taurochenodeoxycholate resulted in an increase in the availability and mean residence time for taurocholate relative to no infusion.

Animals↗
PubMed1990

Selective antagonism of calcium channel activators by fluspirilene.

1. Fluspirilene has been claimed to bind to a high affinity site in the calcium channel in skeletal muscle. We have investigated its calcium-antagonistic effects in smooth muscle and affinity for the channel in radioligand binding assays. 2. Fluspirilene was weakly active as an antagonist of Ca2(+)-induced contractions in K(+)-depolarized taenia preparations from the guinea-pig caecum, with threshold antagonism starting from concentrations of 30 nM. Nitrendipine, nicardipine and nimodipine were very potent antagonists in this model (threshold antagonism, greater than 1 nM). 3. In contrast, fluspirilene (10-1000 nM) was a potent non-competitive antagonist of the effects of Bay K 8644 (1-3000 nM) on Ca2(+)-induced contractions and, at 10 nM, selectively antagonised the effects of Bay K 8644, abolished the Ca2(+)-channel activator effects of CGP 28392, without changing the calcium antagonist effects of nitrendipine, or modifying the sensitivity of the tissues to Ca2+. In contrast, the dihydropyridines were more effective as antagonists of Ca2+ than of Bay K 8644. Fluspirilene therefore selectively antagonised the effects of dihydropyridine Ca2+ channel activators without affecting the antagonist potency. 4. In radioligand binding experiments, fluspirilene was a potent displacer of [3H]-PN-200-110 binding to rat cerebral cortical membranes (EC50 30 nM), albeit with a low Hill slope (0.66), and was more potent than other lipophilic diphenylalkylamines such as flunarizine and lidoflazine. Fluspirilene interacted non-competitively with [3H]-PN-200-110 and increased dissociation of the radioligand.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1989

Developmental potential of avian trunk neural crest cells in situ.

To analyze the developmental potential of individual neural crest cells or their precursors, we have microinjected a vital dye, lysinated rhodamine dextran (LRD), into single cells in the dorsal neural tube. The phenotypes of the descendants that inherited the LRD from the injected cells were evaluated based upon their position, morphology, and neurofilament expression. Individual neural crest cells labeled before or as they emigrated from the neural tube gave rise to both sensory and sympathetic neurons as well as nonneuronal cells, some of which had the morphological characteristics of Schwann cells or pigment cells. In numerous cases, the descendants of a single cell included both neural crest- and neural tube-derived neurons, suggesting that some cells of the peripheral and central nervous systems share a common lineage. Our data demonstrate definitively that both emigrating and premigratory trunk neural crest cells can be multipotent, giving rise not only to cells in multiple neural crest derivatives, but also to both neuronal and nonneuronal elements within a given derivative.

Animals↗
PubMed1989

Reperfusion arrhythmia: myth or reality?

Early reports of "reperfusion arrhythmia" after experimental temporary coronary occlusion raised concern that these arrhythmias, particularly ventricular fibrillation and ventricular tachycardia, might occur in association with reperfusion of an occluded coronary vessel during thrombolysis. Such an occurrence could increase the risk of transfer of such patients. To provide a more definitive answer to this question, we reviewed hospital and transfer records for all patients with acute myocardial infarction transferred by our critical care transfer service between January 1, 1985, and November 30, 1987, noting the occurrence of five types of arrhythmia: ventricular fibrillation, ventricular tachycardia, premature ventricular contractions, bradycardia, and atrioventricular block, both before and during transfer. Five hundred patients with acute myocardial infarction less than 48 hours old were transferred during this period. Two hundred twenty-five patients received thrombolytic therapy; 270 did not (five unknown). The type of acute myocardial infarction was known for 471 patients: 192 were anterior, 203 were inferior, and 76 were lateral. There were no deaths during transfer. Overall survival through hospitalization was 91%. The incidence of arrhythmia was 36% before transport and 12% during transport. There was no difference in arrhythmias overall, or with respect to any of the five arrhythmias specified, between patients who received thrombolytic therapy before and during transport and those who did not. Reperfusion arrhythmia does not appear to be a clinically significant entity during the transport of patients who are receiving IV thrombolytic therapy.

Arrhythmias, Cardiac↗