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Biomedical subjects

B Larsen

Publications and source records attributed to B Larsen.

At least 109 records · Page 6Linked to original sources
PubMed1993

Effect of prolonged alveolar hypoxia on pulmonary arterial pressure and segmental vascular resistance.

The time course of hypoxic pulmonary vasoconstriction and its segmental distribution were studied during prolonged (150 min) alveolar hypoxia in in vivo dog lungs at constant-flow perfusion. With the pulmonary and the systemic circulations separated by two extracorporeal circuits, adequate systemic oxygenation was achieved throughout the experiments. The pulmonary circulation exhibited a time-related biphasic hypoxic vasoconstrictor response: an initial rapid contraction [79 +/- 11% (SE) above control level] was followed by a partial relaxation when a second slow and sustained vasoconstriction (92 +/- 13% above control level) superseded. We partitioned the pulmonary circulation into two segments by arterial occlusion: an upstream arterial segment and a downstream segment consisting of a middle and a venous segment. Measurements were performed at baseline and during the late sustained vasoconstrictor response. Prolonged alveolar hypoxia increased pulmonary capillary pressure by 90 +/- 18%, the site of pulmonary vasomotion being the arterial upstream and downstream middle and venous segments.

Animals↗
PubMed1993

The effects of thermal injury on serum interleukin 1 activity in rats.

Interleukin 1 (IL-1) is present in the blood of burned patients but its pathophysiologic role is not fully understood. Rat models would be useful research tools, if this cytokine could be identified in a complex fluid like blood. We describe a methodology, which revealed IL-1 activity from the serum of burned rats. Serum was collected from 37 rats with 30% total body surface burns and 9 unburned controls. To vary the burn response, the wounds of 17 rats were seeded with nonvirulent Pseudomonas aeruginosa at the time of injury. IL-1 activity was assessed by its capacity to induce IL-2 secretion in murine lymphoma cells (LBRM-33-1A5). Only after the serum had been fractionated, concentrated, and dialyzed, was IL-1 activity uncovered. Sera from burned rats contained five times more IL-1 activity than those from control animals (p < 0.05). There was no difference in serum IL-1 activity between burned and burn-seeded animals. The IL-1 activity was heat labile, and not produced by P. aeruginosa endotoxin, TNF-alpha, or endogenous IL-2 in rat serum. These results confirm that serum IL-1 levels are increased following thermal injury, and that there is no apparent relationship between IL-1 levels and infection. The serum preparation scheme presented in this study offers a reasonable approach to the measurement of serum IL-1 levels in rat models of disease and injury.

Animals↗
PubMed1992

[Effect of 1-year long-term treatment with sucralfate on symptomatic recurrence of duodenal ulcer].

One hundred and two patients, who obtained relief from their duodenal ulcer symptoms with sucralfate (Antepsin R) in a dosage of 2 g b.i.d. for four weeks, were randomized to maintenance therapy with sucralfate 2 g at bedtime or a placebo for one year or until possible recurrence of symptoms. Ninety-four patients completed the study, 46 on sucralfate and 48 on the placebo. Eighteen of the sucralfate-treated patients (39%) experienced relapse of symptoms, as did 36 (75%) of the placebo treated patients. This difference was significant (p = 0.0008). In the sucralfate group most of the symptoms recurred within three months after randomisation, whereas the relapse rate seemed constant in the placebo group. It is concluded that 2 g sucralfate at bedtime is effective in preventing recurrence of duodenal ulcer symptoms.

Adolescent↗
PubMed1992

[Anesthesiologic aspects of multiorgan donation].

As of July 1990 brain death was legally recognized in Denmark thereby rendering transplantation of heart, liver and lung possible. Brain death donors are usually treated in neurosurgical or anaesthetic intensive care units. The staff of these units influence the number of donors and also the quality of organs donated. Physiological factors pertinent to brain death donors and pre- and peroperative donor therapy in relation to multiorgan procurement are discussed from the viewpoint of the anaesthetist. Symptomatic therapy aimed at optimizing and maintaining organ function is employed; thus continuing intensive care. Sympathetic and somatic reflex responses to surgical stimulation are to be anticipated, often necessitating analgesics to blunt haemodynamic responses and neuromuscular blocking agents to inhibit movements and/or rigidity.

Anesthetics↗
PubMed1992

Genetic polymorphism of esterase in plasma of American mink (Mustela vison L.).

Plasma samples of 412 minks, including 20 families and representing 15 lines, have been investigated by isoelectric focusing for the enzyme esterase (ES). The observed variation of the enzyme may be explained as a result of one locus with at least seven codominant alleles. The segregation of six alleles assumed for the locus in 20 families supports this genetic model. Genetic divergence among the lines is observed and may be due to founder effect and/or selection.

Alleles↗
PubMed1992

Dairy breed bull with complex chromosome translocation: fertility and linkage studies.

A chromosome study was performed on the offspring of an American Brown Swiss bull, which was carrier of a complex chromosome translocation. A total of 10 phenotypically normal calves were examined and a similar complex translocation was detected in five calves. The translocation involved identifiable parts of chromosome number one and eight. Furthermore, the terminal band of chromosome one had been translocated to an unidentified chromosome. One of the calves also carried a 1/29 centric fusion chromosome. Pedigree and chromosome analysis showed that the centric fusion originated from another American Brown Swiss bull. A linkage study was performed and an indication of linkage between the Z blood group system and the complex translocation was found. The fertility of the bull was studied, and it was found to have a severely reduced fertility mainly due to an increased rate of early embryonic mortality.

Animals↗
PubMed1992

Effects of chlorhexidine gluconate douche on normal vaginal flora.

The effects of a 0.5% aqueous chlorhexidine gluconate (CHG) douche on the normal vaginal flora of twenty healthy nonpregnant volunteers were investigated. The douche was applied in a premeasured 180-ml quantity daily for 7 consecutive days. Specimens for aerobic and anaerobic culture of the vaginal flora were obtained on 3 occasions from each volunteer, once before and twice after CHG use. The culture results were analyzed qualitatively and quantitatively. A blood sample was also collected within 24 h of the last CHG application to determine serum CHG concentration. Lactobacillus spp., Gardnerella vaginalis and Staphylococcus epidermidis were the most prevalent aerobic bacteria at all phases of the study and Bacteroides spp. were the most prevalent anaerobes. The composition of the normal flora was essentially the same 30 days after the last dose as the pretreatment flora. Small amounts of CHG were detected in the serum of all but one subject. No untoward effects on the participants were observed. Candida albicans counts were slightly higher, but prevalence was not significantly increased at the end of the study.

Adult↗
PubMed1992

Chlamydia trachomatis antigen prevalence among pregnant women in West Virginia.

During 1990, more than 2,100 women who received prenatal care at one of four clinics which serve 11 West Virginia counties, were screened for chlamydial antigen. Overall, 5.6 percent of the women screened had positive antigen tests and 90 percent of these individuals were under the age of 25. The prevalence of chlamydia was different at three geographic sites with the highest rate of positive antigen test being 9.4 percent at one site. These findings led to a careful analysis of the prevalence of this disease among women who lived in rural areas versus those who lived in urban areas. This detailed analysis involved only patients seen in the Grafton and Morgantown clinics, and revealed a tendency for most positive antigen tests to occur among women with urban addresses. Our study indicates that a substantial chlamydial problem exists among pregnant women of young age. Although screening all pregnant women for chlamydia may not be cost effective, knowing which individuals are at highest risk may help target limited screening for these patients.

Adult↗
PubMed1992

Bovine monoclonal alloantibodies to blood group antigens prepared by murine x bovine or (murine x bovine) x bovine interspecies fusions.

In order to obtain monoclonal alloantibodies against bovine blood group antigens, lymph node cells from calves immunized with bovine red blood cells (RBC) were fused with either murine NSO/1 myeloma cells or a HAT sensitive murine x bovine heterohybridoma cell line. Both fusion partners resulted in heterohybridoma cell lines, producing monoclonal alloantibodies against bovine red blood cell antigens. Several clones produced antibodies against identical antigens and some of these clones have been further analysed. The antibodies produced by these selected cell lines have been compared with conventional polyclonal antisera used in bovine blood typing service. Thus extensive tests--including the ISAG Comparison Tests 1989/90 and 1991/92--have proved that monoclonal alloantibodies specific for the internationally recognized bovine red cell antigens A2, I1, O1, Q, A', B', Q', C1, R1, X1, S and Z have been produced. The Q, A', B', and C1 antibodies react weakly with certain phenogroups, whereas the A2, I1, O1, Q', R1, X1, S and Z antibodies have proved to be excellent blood typing reagents and have now substituted the polyclonal antisera in routine bovine blood typing in our laboratory.

Animals↗
PubMed1992

Alpha 1-antitrypsin alleles in patients with pulmonary emphysema, detected by DNA amplification (PCR) and oligonucleotide probes.

Alpha 1-antitrypsin (AAT) deficiency is a serious predisposing factor for the development of pulmonary emphysema. Twelve representative Danish families were studied. AAT typing was performed as a comparative study between the traditional protein typing by isoelectrical focusing and the deoxyribonucleic acid (DNA) technique of enzymatic amplification and subsequent typing with radioactively labelled oligonucleotide probes. On the basis of clinical and radiological signs of pulmonary emphysema, 25 patients were selected. AAT typing was performed by use of the two techniques in combination, in search for new point-mutations among the patients. Results obtained with the two techniques were discordant in one patient, suggesting an unknown variant. The unexpectedly high PiZ frequency of 0.22 found in the study group is discussed.

Adult↗
PubMed1991

Lanosterol 14 alpha-methyl demethylase. Isolation and characterization of the third metabolically generated oxidative demethylation intermediate.

Conditions have been identified which permit metabolic formation of the third oxidized intermediate in the lanosterol 14 alpha-methyl demethylase reaction cascade. Metabolism of either the immediate precursor substrate 3 beta-hydroxylanost-8-en-32-al or lanost-8-ene-3 beta,32-diol under mixed function oxidase conditions affords formation of the intermediate. It must be emphasized that the intermediate can only be detected if saponification procedures are omitted during sterol isolation. Comparative chemical and biochemical studies of the isolated metabolite with 3 beta,15 alpha-dihydroxylanost-8-en-32-al reveal that the metabolite is not the 15 alpha-hydroxylanosterol aldehyde, a putative demethylase intermediate. The metabolite is efficiently converted to the demethylated delta 8,14-diene sterol in the absence of molecular oxygen or NADPH, thus supporting its identity as the final oxidized intermediate in the lanosterol 14 alpha-methyl demethylase cascade. 1H NMR analysis shows a proton resonance at 7.86 ppm consistent with a formyloxy proton. Mass spectral and infrared analysis of the metabolite clearly establish oxygen insertion into the immediate precursor substrate, 3 beta-hydroxylanost-8-en-32-al. Collectively, the biochemical and chemical characteristics of the metabolite support a structural assignment for the metabolite as 14 alpha-formyloxy-lanost-8-en-3 beta-ol.

Animals↗
PubMed1991

Clinical isolates of yeast produce a gliotoxin-like substance.

Candida infections are major causes of morbidity in compromised human hosts, but our understanding of the virulence of Candida remains incomplete. The possibility that toxic fungal metabolites belonging to the chemical class epipolythiodioxopiperzine (ETP), which are reported to possess immunomodulating and antiphagocytic properties may be produced by Candida species was investigated. Reversed phase HPLC analysis of flash evaporated chloroform extracts of 7 day cultures of clinical Candida isolates grown in Minimal Essential Medium (MEM) with 5% fetal calf serum revealed the presence of a compound which eluted at the same time as the ETP, gliotoxin. Of 50 strains of yeast tested, 32 produced this gliotoxin-like material. This material was tested for other properties of ETP type toxins including the presence of mercaptans (Ellman reaction), ultraviolet absorbance spectrum and antibacterial activity against Micrococcus lutea. These tests revealed gliotoxin-like material from yeast cultures to be similar to commercially supplied gliotoxin. This represents the first report of the presence of ETP-like compounds in yeast and raises the possibility that ETP's may contribute to the virulence of the organism.

Aspergillus fumigatus↗