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Biomedical subjects

P Jensen

Publications and source records attributed to P Jensen.

At least 19 recordsLinked to original sources
PubMed1992

[Emergency services in the admission department of a central hospital].

Medical treatment during the evening and night hours has been the subject of debate at present on account of changes in the practitioner-on-call system. The emergency medical service in the catchment region for the Central Hospital in Naestved before these changes was therefore analysed. Services rendered in this region outside working hours, both by the physician-on-call and the hospital, were registered for the period 1.12.1989-31.1.1990. A total of 8,742 consultations occurred during the period, viz every tenth member of the population sought medical advice. The majority of these contacts were with the practitioner-on-call as 7,253 (83%) sought their general practitioner first and the remainder came to hospital. This corresponds to 117 consultations with the practitioner-on-call and 22 visits to the casualty department per 24 hours of emergency service. Among the patients seeking help from the casualty department, it was found that 30% could have been treated in general practice. Among the taks for the practitioner-on-call, there were 27% telephone consultations, 21% in practice and 52% home visits. No differences were observed between urban rural regions as regards the proportions of services but the number of services followed population percentages. 11% sought medical help at night and 1/3 of these patients were referred to hospital. In the present material, there appeared to be relatively great misuse of the telephone number 000 (equivalent to 999) as only 1/3 of these patients were admitted to hospital. A total of 1,263 patients were admitted to hospital and 78% (982) of these had been seen primarily by the practitioner-on-call.(ABSTRACT TRUNCATED AT 250 WORDS)

Denmark↗
PubMed1992

Growth-factor-independence and invasive properties of colorectal carcinoma cells.

During serial passage of the colorectal carcinoma cell line SW1116 in athymic nude mice, we selected 2 variants that metastasized to the lungs and liver. The metastatic capacity of these in vivo variant cell lines was associated with their ability to (1) grow under growth-factor-deprived conditions, (2) invade and transgress a reconstructed basement membrane with high effectiveness, and (3) produce higher activities of the substrate-degrading enzymes collagenase and plasminogen activator as compared to parental cells. To assess the relative contribution of growth-factor-independence and high levels of invasiveness/motility to the metastatic phenotype, variants of 6 colorectal carcinomas were selected in vitro by adaptation to a growth-factor-free culture medium followed by selection of highly invasive cells in chemoinvasion assays. Four out of 6 cell lines selected for growth-factor-independence showed significantly higher levels of invasiveness through reconstructed membranes, suggesting co-segregation of growth-factor-independence and high levels of invasiveness in vitro. Using an in vitro chemoinvasion assay, 2 poorly and 1 highly invasive cell line were further selected for invasiveness. After 6 selection passages, all cell lines were highly invasive and showed high motility rates. However, when injected s.c. into athymic nude mice to test their metastatic capacity in vivo, double-selected variant cell lines did not form spontaneous metastases. Our results indicate that growth-factor-independence and high levels of invasiveness, although associated with the metastatic phenotype, are not sufficient for experimental metastasis formation of colorectal carcinoma cells in vivo.

Animals↗
PubMed1992

Spontaneous echo contrast imaging in infective endocarditis: a predictor of complications?

Infective endocarditis is associated with significant morbidity and mortality. Valvular destruction and congestive heart failure are more common in patients with echocardiographically detectable vegetations. In addition, spontaneous platelet aggregation is increased when vegetations are present on cardiac valves. The aim of the study was to assess the prognostic value of spontaneous echo contrast (SEC) imaging, as SEC is supposed to reflect red blood cell aggregates stimulated by platelet activity. We studied 293 patients with clinical signs of infective endocarditis. Vegetations, attached to the aortic or mitral valve, were found in 130 patients (44.4%) who were followed for a mean period of 12 months. In 34 of these 130 patients (26.2%) SEC was imaged during the initial transesophageal echocardiographic examination. In these patients SEC indicated a prolonged healing of infective endocarditis with a specificity of 91.2%, a sensitivity of 77.3%, a positive accuracy of 77.3%, a negative accuracy of 74.3%. Multivariate analysis revealed that SEC is a risk factor for valve replacement (p less than 0.001) and for embolic events (p less than 0.001), less for mortality (p less than 0.01), and lowest for abscess formation (p less than 0.05). The dose of ADP to induce half-maximal platelet aggregation was significantly lower in patients with SEC (0.71 +/- 0.15 microliters) than without SEC (1.05 +/- 0.12 microliters; p less than 0.05), implying an increased spontaneous platelet aggregation in the presence of SEC. Our data provide evidence that systemically activated coagulation plays an important role in infective endocarditis. SEC, the echocardiographic implication of an increased platelet aggregation, predicts complications such as thromboembolic events and the need for surgery and is closely related to the prolonged healing period of infective endocarditis. In addition to demonstrating vegetations, transesophageal echocardiography provides information helpful in assigning patients to a high-risk subgroup. Transesophageal echocardiography may play an important role in assessing the clinical outcome of these patients.

Adult↗
PubMed1992

Resting energy expenditure, caloric intake, and short-term weight change in human immunodeficiency virus infection and the acquired immunodeficiency syndrome.

To assess the causes of short-term weight loss in patients with acquired immunodeficiency syndrome (AIDS), we measured resting energy expenditure (REE), caloric intake, and the 28-d weight trend in control subjects, human immunodeficiency virus (HIV)+ subjects, AIDS patients, and AIDS patients during secondary infection (AIDS-SI). REE was increased in HIV+ (11%), AIDS (25%), and AIDS-SI (29%). Caloric intake was similar in control subjects, HIV+, and AIDS but reduced 36% in AIDS-SI, who consumed 17% fewer calories than their REE. Average short-term weight was stable for HIV+ and AIDS but decreased 5% in AIDS-SI. Weight trend correlated with caloric intake but not with REE. Thus HIV+ and AIDS are able to partially compensate for increased REE because they do not show short-term weight loss. Decreased caloric intake is critical for short-term weight loss and is seen during secondary infection. Inability of decreased caloric intake to decrease REE during infection accelerates short-term weight loss. Rapid weight loss with anorexia may be a harbinger of secondary infection in AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Characteristics of prosthetic mesh and autogenous fascia in abdominal wall reconstruction after prolonged implantation.

This study evaluated two types of prosthetic mesh and autogenous fascia in long-term abdominal wall reconstruction for rats. Marlex mesh, Gore-Tex patch, and autogenous fascia were implanted and left in place for 1 year. Materials were removed and evaluated using tensile strength of the material, tensile strength of the suture line, and adhesions. No change in the tensile strength of any of the materials were found at 1 year follow-up. Tensile strengths were significantly greater for Gore-Tex patch and Marlex mesh than the autogenous fascia. The Marlex mesh, however, had a weak and a strong tensile strength direction. These were significantly different (p < 0.05). Suture line tensile strength was greater for autogenous fascia and Marlex mesh than it was for the Gore-Tex patch, which was significantly weaker (p < 0.05). The greatest number of adhesions were seen in the Marlex mesh group. No significant difference was present in adhesions between Gore-Tex patch and autogenous fascia. In summary, autogenous fascia showed virtually no adhesions and good suture line strength. While it was the weakest of the three materials examined, the strength was still within the normal range and adequate for abdominal wall reconstruction.

Abdominal Muscles↗
PubMed1992

Noninvasive assessment of metabolism in wounded skin by 31P-NMR in vivo.

Phosphorus-31 nuclear magnetic resonance techniques using shallow penetrating coils have been used to noninvasively monitor severity and metabolic changes over time in skin wounds in rats. Ratios of phosphocreatine (PCr) to inorganic phosphate (Pi) indicate energy status in both thermal wounds and surgical flaps. In partial and full-thickness scald wounds, reductions in PCr/Pi ratios correlated with burn depth and improved over time postinjury, suggesting wound revascularization. No decrease in intracellular pH was noted in these wounds; the phosphate shifts may be primarily the result of tissue degradation followed by restoration of the microvasculature. Distal regions of caudally based dorsal 3 x 10 cm full-thickness skin flaps reveal progressively lower PCr/Pi ratios to 3-6 hours after elevation as well as drops in pH up to 0.5 units, presumably as a result of anaerobic glycolysis in these tissues. After 24 hours, the intracellular pH returned to normal (7.1-7.2) and the PCr/Pi ratios approached 70%-90% of the well-perfused proximal regions within 3-7 days. These results indicate the establishment of a microvasculature from the underlying bed as the distal regions survive as free grafts. The data demonstrate the potential usefulness of the technique in noninvasive measurement of the biochemical response to injury and wound healing in living organisms.

Animals↗
PubMed1992

Lipids, lipoproteins, triglyceride clearance, and cytokines in human immunodeficiency virus infection and the acquired immunodeficiency syndrome.

Infection causes disturbances in lipid metabolism that may be mediated by cytokines. Therefore we studied plasma lipids, lipoproteins, triglyceride (TG) metabolism, and serum cytokines in three groups: patients with the acquired immunodeficiency syndrome (AIDS) without active secondary infection, patients with evidence of human immunodeficiency virus infection but without clinical AIDS (HIV+), and controls. Plasma TGs and FFA were increased in AIDS, while plasma cholesterol, high density lipoprotein (HDL) cholesterol, apolipoprotein-A-1 (Apo-A-1), low density lipoprotein (LDL) cholesterol, and Apo-B-100 levels were decreased. Increased TG levels in AIDS were primarily due to increases in very low density lipoprotein of normal composition; in addition, LDL and HDL were TG enriched. In HIV+, TGs and FFA were not increased, but total cholesterol, HDL cholesterol, Apo-A-1, and Apo-B-100 were significantly decreased. Interferon-alpha (IFN alpha) and C-reactive protein levels were increased in AIDS, but tumor necrosis factor and haptoglobin levels were not. There was a significant correlation between plasma TGs and IFN alpha levels (r = 0.477; P less than 0.01), but not between TGs and tumor necrosis factor, C-reactive protein, haptoglobin, or P-24 antigen. In addition, there was no relationship between circulating IFN alpha levels and plasma cholesterol, HDL cholesterol, Apo-A-1, LDL cholesterol, Apo-B-100, or FFA. TG clearance time and postheparin lipase were significantly decreased in AIDS and HIV+. There was a strong correlation between serum IFN alpha levels and TG clearance time in AIDS and HIV+ (r = 0.783; P less than 0.001). In summary, decreases in cholesterol and cholesterol containing lipoproteins (including HDL) in both AIDS and HIV+ precede the appearance of hypertriglyceridemia and are not related to IFN alpha or TG levels. Our data raise the possibility that with development of AIDS, subsequent increases in IFN alpha may contribute to increases in plasma TG levels in part by decreasing the clearance of TG.

Acquired Immunodeficiency Syndrome↗
PubMed1979

Functional additive effect of H blood group alleles on carcass length in Danish landrace pigs.

Previous investigations have revealed statistically significant associations between H blood group genotypes and carcass length in Danish Landrace pigs. The same data were subjected to an analysis aimed at a genetic interpretation of the associations. The regression of the average carcass length (in cm) on the average number of H- alleles for individuals within three genetically characterized classes was 0.725 and the correlation coefficient was 0.995. The results indicate that the associations can be interpreted as being due to an additive effect of the H blood group alleles on carcass length. The additive effect is designated as being functional. A similar effect is expected with respect to any allelic pair exhibiting linkage disequilibrium with alleles at the H locus.

ABO Blood-Group System↗
PubMed1978

Method for determining complex operator noise exposures.

This procedure describes a field method for determining operator noise exposures that cannot be assessed from single sound level meter readings. Noise exposures that should be evaluated by this method are those characterized by time-varying operator position sound levels--sound levels that change by three decibels or more while the meter is being read. The method is based on statistical concepts and requires multiple readings for a sample period whose length is prescribed by the desired precision of the results. This new procedure compares well with the theoretical accuracy of the best dosimeters. The actual performance of the new method has been shown to be better than the actual performance of the dosimeters.

Environmental Exposure↗
PubMed1977

The effect of A23187 upon calcium metabolism in the human lymphocyte.

Treatment of human peripheral lymphocytes with mitogenic concentrations of the divalent cation ionophore A23187 led to an initial marked increase in the uptake of calcium by these cells, but the amount of accumulated calcium retained decreased with time so that after 8-12 h of culture, the calcium content of treated cells was only 1.5-2.0-fold higher than that of control cells. Three possible explanations for the biphasic nature of ionophore-induced calcium uptake were considered: (1) the ionophore underwent chemical or metabolic inactivation upon prolonged incubation; (2) massive accumulation of calcium caused irreversible uncoupling of mitochondria in these cells with consequent loss of accumulated calcium; or (3) with time there was a redistribution of ionophore within the cell, and sufficient ionophore was taken up by internal, most likely mitochondrial, membranes to cause an efflux of calcium from internal stores. By developing a bioassay for ionophore and examining the time-dependent effects of ionophore in the presence and absence of calcium, it was concluded that the third explanation was the most likely. The general implications of these results are discussed.

Anti-Bacterial Agents↗
PubMed1977

The mitogenic effect of A23187 in human peripheral lymphocytes.

The mitogenic action of the divalent ionophore A23187 was confirmed and shown to be very sensitive to changes in extracellular calcium ion concentration. At optimal calcium and ionophore concentrations, an increase in [3H]-thymidine incorporation was seen that was similar to that seen after phytohemagglutinin addition. A calcium-dependent stimulation of alpha-aminoisobutyric acid transport was also seen after A23187 addition. Studies with three inhibitors demonstrate a similarity between proliferation induced by phytohemagglutinin and by A23187. Isoproterenol (10(-4) M) and ouabain (10(-7) M) blocked the effects of phytohemagglutinin and A23187. A drug, D-600 that has been shown to block calcium channels in cardiac muscle, inhibited proliferation induced by either phytohemagglutinin or A23187. This concentration of D600 had no effect on either phytohemagglutinin- or A23187-induced 45Ca2+ uptake. Furthermore, the (+) and (-) isomers separated from racemic D600, which have been shown to block sodium and calcium channels respectively in smooth muscle, had equal potency in blocking lymphocyte proliferation.

Aminoisobutyric Acids↗
PubMed1977

Epithelial ingrowth.

A 74-year-old woman had a radical anterior segment resection for epithelial ingrowth following cataract extraction. Light microscopy demonstrated the presence of a sheet of cells morphologically similar to conjunctival epithelium covering the superior half of the inner surface of the cornea, iris, and ciliary processes. Electron microscopy revealed that frequent hemidesmosomes and a well-developed basal lamina were consistently present along the base of the ingrowing epithelium. The tissue immediately beneath the ingrowing epithelium, lining the cornea, trabecular meshwork and iris, morphologically resembled the subepithelial zone that has been described along the human skin epidermal-dermal junction. Additionally, focal areas of necrosis were noted in the trabecular meshwork. The major structural alterations induced on the surfaces of intraocular structures by the invading epithelium and the associated necrosis probably are responsible for the glaucoma which occurs with epithelial ingrowth.

Aged↗
PubMed1976

Calcium ion as second messenger.

The role of calcium as an intracellular messenger in the activation of eukaryotic cells is discussed. Particular emphasis is devoted to: (1) the interrelationship between cell activation by chemical stimuli and alterations in intracellular calcium metabolism, and (2) the interrelated roles of calcium and the cyclic nucleotides, cyclic AMP and cyclic GMP, in achieving the final integrated, co-ordinated cellular response.

Adenylyl Cyclases↗
PubMed1976

The dependence of tension relaxation in skeletal muscle on the number of sarcomeres in series.

Mulieri (1972) has reported that the depth of the latency relaxation, tension relaxation, changes only insignificantly when about half of a fibre bundle is wound tightly around a small glass rod. From this observation he concludes that the tension relaxation is not correlated with the number of sarcomeres in series in a frog muscle fibre. The dependency of the tension relaxation on the number of sarcomeres in series has been reinvestigated using both Mulieri's method and other independent methods. When Mulieri's experimental procedure was repeated, his result was reproduced. In the other methods used the tension relaxation was found to be proportional to the number of sarcomeres in series which were activated initially. This result was also obtained by introducing a slight modification to the procedure used by Mulieri. The results could equally well be understood if the latency relaxation was caused by a definite elongation rather than an increase in compliance of the fibre.

Action Potentials↗