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Biomedical subjects

T Jensen

Publications and source records attributed to T Jensen.

At least 235 records · Page 13Linked to original sources
PubMed1980

Changes in transfer ribonucleic acid population of Acanthamoeba castellanii during growth and encystment.

Fifteen aminoacyl-transfer ribonucleic acids (tRNA's) from vegetative cells (trophozoites) and mature cysts of Acanthamoeba castellanii were compared by reversed-phase 5 chromatography. Little or no differences were detected in reversed-phase 5 chromatography elution profiles of alanyl-, arginyl-, isoleucyl-, phenylalanyl-, prolyl-, seryl-, threonyl-, tryptophanyl- and valyl-tRNA's. Significant differences in the relative proportions of isoaccepting species of leucyl-, lysyl-, methionyl-, aspartyl-, histidyl-, and tyrosyl-tRNA's were observed. Based upon the criterion of cyanogen bromide reactivity with the modified nucleoside queuosine, the content of queuosine in aspartyl-tRNA of A, castellanii is significantly greater in mature cysts than in trophozoites. The similarity of change in reversed-phase 5 chromatography elution profiles of aspartyl-, histidyl-, and tyrosyl-tRNA suggests that a common mechanism is responsible for alterations in the chromatographic patterns.

Amoeba↗
PubMed1979

The effect of sulpiride induced hyperprolactinaemia on glucose tolerance and insulin secretion in normal subjects.

Blood glucose concentration and insulin secretion expressed by peripheral plasma insulin (IRI) and C-peptide levels were measured during saline and sulpiride infusion in five normal men. In another experiment the same variables were analysed in six normal males before and during oral sulpiride treatment for 5 days. The i.v. and oral administration of sulpiride resulted in a significant rise in serum prolactin levels. The stimulated serum prolactin concentrations were equivalent to those seen during stress. The sulpiride induced hyperprolactinaemia did not change blood-glucose, plasma IRI levels, hepatic insulin removal and glucose utilization during basal conditions or after i.v. glucose administration.

Adult↗
PubMed1977

Techniques for localized injections and topical applications of carcinogens at specific endobronchial sites in dogs.

We seek to create a canine lung cancer model with sharply localized carcinomas analogous to human lung cancers. Toward this goal techniques for recurrent endobronchial transbronchoscopic submucosal injections and topical applications of the carcinogens 3,4-benzo(a)pyrene and N-methyl-nitrosourea have been developed. After 2 years of experience with 2,868 endoscopic manipulations and varying dosage schedules in 59 dogs, safe effective techniques for recurrently delivering carcinogens and sequential biopsies of the same sites have evolved. Predominantly during the first year of experience, 10 dogs died as a consequence of technical problems such as exsanguinations after 1 mm. punch biopsies. There were also 39 instances of nonlethal technical complications of endoscopy in the face of immunosuppression and local irritation caused by the carcinogens. By the techniques and dosage schedules described, it has now become possible reliably and safely to create impressive localized bronchial preneoplasia with squamous metaplasia and atypia among the prominent features.

Administration, Topical↗
PubMed1974

Changes in transfer ribonucleic acids accompanying encystment in Acanthamoeba castellanii.

Transfer ribonucleic acid (tRNA) from exponentially growing cells (trophozoites) and from precysts of Acanthamoeba castellanii were examined by reversed-phase column (RPC-2) chromatography. This system gave excellent resolution of isoaccepting species of tRNA. The tRNAs for 12 amino acids were studied. A comparison of trophozoite and precyst tRNA elution profiles revealed no apparent differences in the number of isoaccepting species of alanyl-, arginyl-, asparaginyl-, glycyl-, leucyl-, lysyl-, methionyl-, phenylalanyl-, tryptophanyl-, or valyl-tRNAs. Seryl-tRNAs from trophozoites were eluted as three components, whereas precyst seryl-tRNAs were eluted as only two components. Precharged trophozoite and precyst isoleucyl-tRNAs were both eluted as single components; however, post-chromatography charging of trophozoite tRNA resulted in three components of activity for tRNA(Ile) and only one component for precyst tRNA(Ile). None of the observed changes could be attributed to differences in synthetases or to the presence of altered tRNA lacking the CCA terminus or partially degraded by nucleases. The possible significance of these observations is discussed.

Acylation↗
PubMed1971

Gonococcal tonsillar infections.

Neisseria gonorrhoeae were cultured from tonsillar swabs in six men and six women out of 161 consecutive, unselected, Danish patients (95 men and 66 women) suffering from urogenital or rectal gonorrhoea. Gonococci were found in the tonsils in only one out of 49 foreign men with gonorrhoea. Eleven of the Danish patients admitted orogenital contact at their most recent intercourse. The gonococcal complement fixation test was negative in all except two cases. Standard singledose treatment cured the urogenital and rectal infections promptly but failed to cure the tonsillar infection in five cases, and in recalcitrant cases the organisms were demonstrable for some months.

Ampicillin↗
PubMedDate not supplied

Multiple column synthesis of a library of T-cell stimulating Tn-antigenic glycopeptide analogues for the molecular characterization of T-cell-glycan specificity.

A series of peptides and glycopeptides derived by amino acid and glycosyl amino acid scans through the self peptide from CBA/J mouse haemoglobin Hb (67-76). VITAFNEGLK, was synthesized by multiple column peptide synthesis (MCPS). Investigation of glycopeptide binding to the mouse major histocompatibility class II molecule Ek showed that glycans in position 72 did not interfere with the binding to Ek. Immunization experiments revealed that glycopeptides with the glycan in position 72 were immunogenic. Therefore a series of N-linked and O-linked glycopeptides with the glycan attached in the position 72 either to serine, threonine or asparagine was synthesized by MCPS. The glycan structure was furthermore varied with respect to monosaccharide component, size of oligosaccharide, anomer configuration and stereochemistry of essential hydroxyl groups in order to investigate the specificity of the interaction with the T-cell receptor. Easy synthesis of ready to use Ser and Thr building blocks corresponding to mucin core 1, the Tn-antigen and its beta-anomer were developed using trichloroacetimidates as glycosyl donors and reduction with in situ acetylation of the azide containing glycosylation products. Synthesis of an alpha-linked GlcNAc-Thr building block was achieved by glycosylation of Fmoc-Thr-OPip with 2-azido-2-deoxy-3,4,6-tri-O-acetyl-D-glycopyranosyl trichloroacetimidate as a glycosyl donor. Other building blocks were obtained by previously described procedures.

Animals↗
PubMedDate not supplied

The role of hypertension in the development of nephropathy in type 1 (insulin-dependent) diabetes mellitus.

Which comes first when developing clinical diabetic nephropathy, the blood pressure rise or the increasing urinary albumin excretion? This issue is discussed based on recent literature of studies in humans with Type 1 (insulin-dependent) diabetes mellitus. We conclude that hypertension has a central role in the progression of diabetic nephropathy and has deleterious effects on the life expectancy of patients who already have signs of diabetic renal disease in terms of elevated urinary albumin excretion. However, blood pressure is preceded by small increments of urinary albumin excretion rates, an indicator of universally increased vascular leakiness, and thus does not seem to be the cause of diabetic nephropathy.

Blood Pressure↗
PubMedDate not supplied

The measurement of hemoglobin A1. Evaluation of an 'aldimine eliminator'.

The efficiency of a newly introduced 'hemoglobin A1 aldimine eliminator' in minimizing the effect of recent fluxes of glucose on the determination of total glycosylated hemoglobin (HbA1) was evaluated by comparing HbA1 values measured during morning fast and again 6 h postprandially in 26 insulin-dependent diabetic subjects by Isolab's Fast Hemoglobin Test System employing dialyzed and aldimine eliminator-added non-dialyzed hemolysate. The HbA1 values determined by this microcolumn procedure were also compared with those of the conventional macrocolumn method of Trivelli. HbA1 measured by the microcolumn procedure and aldimine eliminator using non-dialyzed hemolysates did not differ from the HbA1 values based on dialyzed hemolysates, and a good correlation was found between the macrocolumn method and the Isolab's Fast Hemoglobin Test System employing both aldimine eliminator added non-dialyzed hemolysate (r = 0.88, p less than 0.001) and dialyzed hemolysate (r = 0.97, p less than 0.001). When 6 h changes were assessed, the mean blood glucose had increased from 11.7 to 15.5 mmol/l (p less than 0.001), and no significant increase in HbA1 occurred when HbA1 was assayed in aldimine eliminator-added non-dialyzed hemolysates (mean fast HbA1: 11.7% and mean postprandial HbA1: 11.8%). Therefore, the use of the HbA1 aldimine eliminator appears to be valuable, practical and time-saving.

Adolescent↗