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Biomedical subjects

K Alexander

Publications and source records attributed to K Alexander.

At least 91 records · Page 5Linked to original sources
PubMed1991

[Hemodynamic effects of intermittent intra-arterial infusion treatment with prostaglandin E1 in peripheral arterial occlusive disease].

14 femoral arteries of twelve patients with peripheral arterial occlusive disease (Fontaine stage II: n = 4, stage III/IV: n = 10) were investigated before, immediately after a series of 26 (ten to 52) intraarterial infusions with prostaglandin E1, and 30 weeks later. Using combined B-mode and pulsed Doppler (duplex) ultrasound blood flow measurements were performed in the common femoral, the superficial femoral, and the deep femoral artery. There was a significant decrease of resting blood flow volume in the common femoral artery after therapy (418.5----362.2 [p less than 0.01]----324.5 ml/min [p less than 0.05]) in the group of patients treated successfully. The peak flow (maximum value of blood flow volume during reactive hyperaemia) in the common femoral artery increased significantly after therapy (597.3----779.1 [p less than 0.05]----843.7 ml/min). The increase of peak flow correlated well with clinical improvement. Other parameters (blood flow velocities, pulse rise time, pulse decrease time, pulsatility index) changed without correlation to clinical outcome. The increase of peak flow after therapy might be caused by an improved collateral circulation, and the decrease of resting blood flow might be due to metabolic effects of prostaglandin E1 (improved oxygen utilization).

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PubMed1991

Intravenous infusion of iloprost in arterial occlusive disease: dose-dependent effects on skin microcirculation.

Transcutaneous oxygen pressure (tcPo2), laser Doppler flux and capillary microscopy have been used to examine the forefoot skin in 5 healthy men and 8 patients with severe peripheral arterial occlusive disease in order to evaluate the dose dependent effects of iloprost on skin microcirculation. Iloprost was infused IV starting at 0.0625 ng.kg-1.min-1 and doubling the dose every 15 min up to 2 ng.kg-1.min-1. While tcPo2 at an electrode core temperature of 44 degrees C decreased in both patients and controls, there was a significant dose dependent increase in tcPo2 (37 degrees C) in the controls from 0.25 ng.kg-1.min-1. In the patients the reaction was variable: it was decreased in two and increased in 6, with a maximum either at 0.25-0.5 ng.kg-1.min-1 (n = 3) or at the highest dose (1.0 or 2.0 ng.kg-1.min-1; n = 3). Mean laser Doppler flux in both groups was increased, although the reaction was not consistent in the patients. Density of forefoot skin capillaries was reduced in 3 patients, and in the others the flow velocity was very low. During infusion of iloprost, both an increase in capillary density and blood cell velocity were observed. The effects were of variable intensity and occurred at varying doses, some appeared early and diminished as the dose was increased, and others were found only at 2 ng.kg-1.min-1. Adverse effects were numerous, extending from harmless skin flushing to mental changes and a quickly reversible attack of angina pectoris.(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMed1991

A phosphoglycerate kinase-like molecule localized to glycosomal microbodies: evidence that the topogenic signal is not at the C-terminus.

The phosphoglycerate kinase (PGK) gene complex of Trypanosoma brucei contains three tandemly linked related genes. One gene encodes a cytoplasmic PGK, while another encodes a PGK isozyme localized to glycosomal microbodies. In this communication, we report that the third gene in this complex encodes a 56-kDa molecule which is also localized to the glycosomal core. DNA sequence analysis indicates that this gene contains multiple substitutions and a large insertion in the amino domain, but that it is very similar to the other PGK isozymes in the carboxy domain. The C-terminal tripeptide is identical to that of the cytoplasmic isozyme, and only one conservative change occurs in the last 25 amino acids. The encoded protein, p56, thus contrasts with the many peroxisomal microbody proteins in which the C-terminal tripeptide contains sufficient information for targeting to peroxisomes. Multiple mechanisms may exist for targeting proteins to the protein cores of microbody organelles. Comparisons of the DNA sequences of several alleles suggest that homologous recombination plays a role in the generation of allelic diversity.

Alleles↗
PubMed1991

Drug use patterns in Northern Territory Aboriginal communities 1986-1987.

During April to November 1986 and May to October 1987, a systematic survey of patterns of use of alcohol, kava, tobacco and analgesics by Northern Territory Aboriginal people aged 15 years and older was conducted. The objectives of the study were to ascertain the prevalence of drug use, the frequency of drug use and the quantity of drugs used. In addition, information about Aboriginal people's perceptions of the drugs, their beliefs about drug use and the value of drugs in their culture was collected. This paper describes only the quantitative aspects of drug use of this population. A stratified sampling procedure was used to sample 10 per cent of the target population. Using two survey instruments, an individual questionnaire and a group questionnaire, data were gathered from 1764 Aboriginal people living in the Northern Territory. As a whole, the Northern Territory Aboriginal people have a drug consumption pattern quite distinct from urban Australians.

Journal Article↗
PubMed1991

[Risk factors for early fatality of ruptured abdominal aortic aneurysms].

Early mortality (EM) following surgery for ruptured abdominal aneurysm continues to be extremely high. In the literature EM still ranges between 30 and 85%, despite improvement of surgical intervention and perioperative management in the recent years. Numerous studies investigate intra- und postoperative parameters, but little is known about preoperative transportation circumstances and the clinical condition prior to intervention. The transportation system at our clinic allowed a complete retrospective assessment of these parameters which were included into the evaluation of the risk factor analysis of the study. From 1974 to 1986 142 patients (131 male, 11 female, mean age: 68.8 years [46-89 years]) were operated on ruptured abdominal aneurysms. Time intervals prior to admission and surgical intervention as well as perioperative data were retrospectively assessed. The patients were divided in: deceased (D) within 30 days and survivors (S). Late survival was assessed either by letter or telephone interview. Age and sex showed no influence on the early mortality. Transportation time and time interval: admission/operation were similar in both groups. The shockindex showed a significant difference. D: 1.1 +/- 0.27; S: 0.8 +/- 0.16. Anuria was seen in 66% of the diseased and 26% of the surviving patients. If free perforation was detected 20 of 30 patients died. The total amount of transfusion differed significantly: D: 6.8 +/- 2.51; S:3.9 +/- 2.01. If diaphragmal X-clamp was necessary 7 of 8 patients died. The necessity of catecholamine support postoperatively was 64% for deceased patients. Dialysis was necessary in 77.8% of the deceased patients. 84% of D developed an ileus and 67% of D developed a pneumonia.(ABSTRACT TRUNCATED AT 250 WORDS)

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