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Biomedical subjects

B Jensen

Publications and source records attributed to B Jensen.

At least 127 records · Page 7Linked to original sources
PubMed1984

Quantitative relationships between structure and pharmacokinetic parameters using molecular connectivity chi indices I: Substituted 2-sulfapyridines.

Quantitative relationships between the structure and pharmacokinetic parameters of several compounds have been derived using the molecular connectivity approach. The correlation coefficients of equations obtained using the Chi indices (chi) as predictor parameters were compared favorably with those obtained by the linear free energy approach, where physicochemical parameters have been used as predictor variables. High correlation coefficients (r) for the first-order elimination rate constant (r = 0.86), total body clearance (r = 0.89), and protein binding association constant (r = 0.78) for substituted 2-sulfapyridines were obtained. However, including the pKa (indicative of electronic effects) of the compounds within the equation as a predictor variable caused an increase in the correlation coefficients.

Chemical Phenomena↗
PubMed1984

Clinical correlates of dementia and disability in Huntington's disease.

The relationship of duration of illness and severity of neurological impairment to psychometric performance and activities of daily living was examined in 57 patients with Huntington's Disease (HD). As earlier studies suggested, a distinct cognitive profile characterized patients early in the disease. Duration of symptoms, however, proved to be a weaker correlate of cognitive decline than was motor impairment at the time of testing. For predicting adaptive functioning, both duration of symptoms and neurological status were important variables. This study underscores the limitations of length of illness as a classificatory variable in studies of dementia in HD. We further suggest that future studies consider the contribution of defects in precise timing and sequential operations to the cognitive and adaptive deficits of these patients.

Adult↗
PubMed1984

Familial premature ovarian failure.

Premature menopause, ovarian failure younger than 40 years of age, is relatively rare but may preclude childbearing for some women who delay attempts at fertility. We present five kindreds in which a genetic association for premature ovarian failure is strongly suggested. Transmission is either autosomal or (less likely) X-linked dominant in these examples. Chromosomal abnormalities, history of diseases, and toxic chemical or viral exposures previously associated with premature ovarian failure could not be demonstrated in these women. This suggests that these kindreds all represent familial idiopathic premature ovarian failure. These data support the need for menopausal histories on both sides of the family for women seeking to postpone reproduction, as well as for patients with ovarian failure.

Adult↗
PubMed1983

Urinary prostaglandin E2 and vasopressin excretion in essential fatty acid-deficient rats: effect of linolenic acid supplementation.

Three groups of weanling male rats were fed on a fat-free diet for 13 weeks. One group received only the fat-free diet (FF rats), the other 2 groups received the fat-free diet and a daily supplement of 2 energy% ethyl linoleate ([n-6] rats), or 2 energy% ethyl linolenate ([n-3] rats). Urinary excretion of prostaglandin E2 (PGE2), immunoreactive arginine vasopressin (iAVP), and kallikrein were determined. PGE2 was quantitated with a radioimmunoassay having 4.9% cross-reactivity with prostaglandin E3 (PGE3). After 4 weeks on the diet, water consumption and urinary iAVP excretion increased significantly in the FF rats and the (n-3) rats compared with the (n-6) rats. Urinary PGE2 excretion was the same for all 3 groups during the first 10 weeks; thereafter it decreased in FF rats and (n-3) rats compared with the (n-6) rats. There was no difference in urinary PGE2 excretion between the FF rats and the (n-3) rats, even though large differences were found in the percentage of arachidonic acid (20:4[n-6]), icosapentaenoic acid (20:5[n-3]), and icosatrienoic acid (20:3[n-9]) of total kidney fatty acids as well as of kidney phosphatidylinositol fatty acids. Fractionation of urine extracts on high performance liquid chromatography with radioimmunoassay detection indicated that (n-3) rats excreted very little PGE3, if any. Urine output followed the same pattern, as did urinary PGE2 excretion. Urinary kallikrein was estimated at week 12 only. It was found to be significantly lower in FF rats and (n-3) rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Alprostadil↗
PubMed1983

Extremely decreased release of prostaglandin E2-like activity from chopped lung of ethyl linolenate-supplemented rats.

Three groups of weanling male rats were reared on a fat-free diet for 13 weeks. One group received only the fat-free diet (FF rats), the other 2 groups received the fat-free diet and a daily supplement of 2 energy% ethyl linoleate ([n-6] rats), or 2 energy% ethyl linolenate ([n-3] rats). The chopped lung preparation was used to illustrate an in vitro prostaglandin formation. PGE2-like activity was quantified on rat stomach strip. The release of PGE2-like activity expressed as ng PGE2-equivalent per g lung tissue (mean +/- SD) was 23 +/- 7, less than 6, and 65 +/- 20 for the FF rats, the (n-3) rats, and the (n-6) rats, respectively. PGE2 quantification by radioimmunoassay of the chopped lung effluent collected after passing over the rat stomach strip revealed the same release pattern as the bioassay. Fractionation of chopped lung effluent on HPLC with radioimmunoassay detection indicated that the lung tissue from (n-3) rats released very little PGE3, if any, in spite of a 20:5(n-3)/20:4(n-6) ratio of 5.2 in the lipids of the lung. It is suggested that the pool of arachidonic acid for prostaglandin production in vitro is different from the one which functions in vivo, and the these pools are differently affected by dietary EFA.

Animals↗
PubMed1983

Dialyzability of methyl-GAG.

Methyl-GAG at low doses was administered to an anephric male patient with metastatic hypernephroma, who required hemodialysis. No toxicity was observed. Measurement of serum levels of methyl-GAG showed that the drug is dialyzable. Thus, when methyl-GAG is considered for patients who are anephric and are being dialyzed, full doses are allowable. In addition, dialysis should be effective in rapidly eliminating the drug in patients who develop toxic effects.

Adenocarcinoma↗
PubMed1981

Statistical evaluation of the lymphocyte proliferation assay with non-stimulated cultures.

A micromethod for the lymphoproliferative assay has been evaluated statistically with non-stimulated human lymphocyte combinations. Different variance components were estimated by means of a hierarchical analysis of variance. Instead of using an arbitrary value for a significant difference between stimulated and non-stimulated cultures, the value can be calculated on the basis of the components of variance in the experimental design. The method disclosed systematic differences between the values of control cultures depending on the lymphocyte combinations and groups of persons examined, which underlines that every experiment should always contain non-stimulated cultures. Further, cell-cell cooperation and differences in spontaneous DNA synthesis within individual lymphocyte populations could be demonstrated.

Analysis of Variance↗
PubMed1980

Yeast mutants auxotrophic for choline or ethanolamine.

Three mutants of the yeast Saccharomyces cerevisiae which require exogenous ethanolamine or choline were isolated. The mutants map to a single locus (cho1) on chromosome V. The lipid composition suggests that cho1 mutants do not synthesize phosphatidylserine under any growth conditions. If phosphatidylethanolamine or phosphatidylcholine, which are usually derived from phosphatidylserine, were synthesized from exogenous ethanolamine or choline, the mutants grew and divided relatively normally. However, mitochondrial abnormalities were evident even when ethanolamine and choline were supplied. Diploids homozygous for the cho1 mutation were defective in sporulation. Growth on nonfermentable carbon sources was slow, and a high proportion of respiratory-deficient (petite) cells were generated in cho1 cultures.

Choline↗
PubMed1980

Fast-responding flow-independent blood gas catheter for oxygen measurement.

Analytic expressions were derived for the response time, flow dependency, and signal-to-background ratio of blood gas catheters. These expressions were utilized to optimize the design of a new catheter. The catheter was tested in vitro and in vivo, and shown to be fast responding and practically flow independent, with an acceptable signal-to-background ratio.

Animals↗
PubMed1977

Antigen specific lymphocyte activity in vitro by peripheral blood leucocytes from Mantoux positive and negative human beings. I. Comparison of quantitative and qualitative differences in the PPD-specific lymphoproliferative response of lymphocytes from the two kinds of donors.

Lymphocytes from some PPD (purified protein derivative from tubercle bacillus) skin test negative (Mantoux negative=Mx--) human beings reacted against PPD in the lymphoproliferative assay with a time course and dose response very similar to those of lymphocytes from Mantoux positive (Mx+) individuals. Other Mx-- persons were PPD non-responsive in the lymphoproliferative assay. The PPD response of (immunoglobulin=Ig) Ig anti-Ig column passed lymphocytes (T-cells) from Mx--/LP+ (LP+=lymphoproliferative) persons was significantly reduced whereas the in vitro PPD response of T-lymphocytes from Mx+/LP+ was the same or increased. Purified B-lymphocytes from all kinds of tested individuals did not respond in vitro against PPD. Serological investigations indicated that one of the reasons for the negative skin reaction of individuals whose lymphocytes gave a positive lymphoproliferative response against PPD in vitro, is that such individuals had recirculating PPD of high molecular weight (greater than 900,000) and/or PPD anti-PPD antibody complexes in the serum. These substances could block the PPD-specific T-lymphocytes.

Adult↗