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Biomedical subjects

A Jung

Publications and source records attributed to A Jung.

At least 109 records · Page 6Linked to original sources
PubMed1994

Localization of calcium entry through calcium channels in olfactory receptor neurones using a laser scanning microscope and the calcium indicator dyes Fluo-3 and Fura-Red.

The intracellular calcium concentration [Ca2+]i in olfactory receptor neurones of Xenopus laevis was imaged with high spatial and temporal resolution. A new method using a mixture of the calcium indicator dyes Fluo-3 and Fura-Red was employed. The fluorescence patterns in two wavelength bands were measured on the emission side of a confocal laser scanning microscope, and the ratio R of the fluorescence intensities was taken as an estimate of [Ca2+]i. When the neurones were depolarized by elevating the extracellular potassium concentration [K+]o they showed one of three types of responses: a fast increase in [Ca2+]i, a slow increase in [Ca2+]i, or no change in [Ca2+]i. The fast increase in [Ca2+]i took place in the soma compartment. For at least 4 s after the onset of depolarization the calcium distribution in the dendrite remained essentially unchanged. To study the fast increase with high time resolution, line scan images were taken. The neurones were depolarized for brief periods applying a solution containing high [K+] onto the soma from an application pipette. The fast increase in [Ca2+]i began with a delay of about 200 ms and went from the resting concentration to about 110 nM above resting concentration. Following the depolarization, recovery from elevated [Ca2+]i to resting levels had a time constant of about 15 s. The slow response seemed to depend on the removal of [Na+] from the bath rather than on the elevated [K+] in the bath. The response was also observed with Cd2+, Ni2+, and Co2+ (1.5 mM each) in the bath.(ABSTRACT TRUNCATED AT 250 WORDS)

Aniline Compounds↗
PubMed1994

[Thymus-like expression and molecules accessory to division and of thymocyte-stroma interactions in thymomas: a prerequisite for the establishment of an abnormal T-cell repertoire?].

Costimulatory stromal receptors were identified in thymuses and myasthenia gravis (MG)-associated thymic epithelial tumors (TETs) by immunohistochemistry. ICAM-1 occurred in areas with medullary or cortical differentiation of TETs and thymuses. B7 and LFA-3, absent in the normal cortex, were hyperexpressed in cortical type TETs. VCAM-1, confined to endothelium and dendritic cells in cortex and medulla, was focally expressed by epithelial cells of a medullary thymoma. We suggest that aberrantly expressed costimulatory molecules may contribute to the pathogenesis of paraneoplastic MG by an intratumorous activation of mature T cells.

Antigens, CD↗
PubMed1994

Distribution of molecules mediating thymocyte-stroma-interactions in human thymus, thymitis and thymic epithelial tumors.

Two findings in thymic epithelial tumors are correlated with the occurrence of myasthenia gravis(MG): (1) the expression of an acetylcholine receptor (AChR)-like-epitope in the neoplastic epithelium, and (2) the preservation of thymus-like features in the neoplasms, indicated by the presence of immature thymocytes. On this background it has been proposed that paraneoplastic MG may start with an intratumorous abnormal T cell selection due to aberrantly expressed AChR-epitopes (self-peptides). As appropriate thymocyte-stroma-interactions are prerequisites for thymocyte development in the thymus (and probably in MG-associated thymic tumors, too), we analyzed the expression of CD28/B7(BB1), CD2/:LFA3, LFA-1/ICAM-1 and VLA-4/VCAM-1 in human thymus and thymomas by immunohistochemistry. In normal thymuses and thymitis the stromal molecules were expressed at higher levels in the medulla than in the cortex. This was particularly true for B7(BB1) that was undetectable by immunoperoxidase techniques in the cortex. In contrast, cortical-type thymic epithelial tumors (cortical thymoma and well differentiated thymic carcinoma), known to exhibit the highest association with myasthenia, expressed the stromal molecules at almost medullary levels. The findings may be a clue to a functional difference between neoplastic and normal cortical epithelial cells: while we find the former to have the capacity to present soluble antigen to antigen-specific CD4+ T cells in vitro, normal cortical epithelium failed to do so. This altered microenvironment in thymomas might contribute to the autoimmunization by stimulating mature recirculating AChR-specific T cells.

CD2 Antigens↗
PubMed1994

[The so-called "minor hand injury" and its socioeconomic sequelae].

A study was carried out involving 167 patients who had received primary treatment in alio loco for injuries diagnosed as 'minor cuts, twists and sprain', and who were then seen in the out-patient department at a later date. The patient group was analyzed with regard to the following: a more precise identification of the initial injury, the initiated treatment regimen and more particularly, the socio-economic consequences of the injury. Duration of treatment programmes, loss of working days and compensatory payments were cost-analyzed. The results showed that a delayed primary surgical intervention was possible in only 17% of cases, it was necessary to alter the treatment regimen in 29% and in 28% it was no longer realistic even to initiate treatment. Comparisons between this population and a group of a patients who had received adequate primary care showed that in the study group length of treatment and days lost at work was prolonged by the factor 1.3; furthermore the number of cases in which the reduction of working ability was 20% and more was increased by 2.7. Increased costs incurred by financial compensations were approx. DM 27,000/patient.

Absenteeism↗
PubMed1994

Shoulder instability caused by rotator cuff lesions. An in vitro study.

Although many clinical and experimental studies have been published on shoulder instability, little is known about the relationship between degenerative changes of the cranial part of the rotator cuff and shoulder instability. The fact that some cuff lesions cause few symptoms and do not progress, while others are not only incapacitating but also progress to massive ruptures and cuff arthropathy, is still not well understood. In this study the motion patterns of the intact joint, and changes induced by a division of the supraspinatus tendon alone or of the supra- and infraspinatus tendons, were investigated in cadaver specimens. The results demonstrate that a one tendon lesion does not influence the motion pattern, whereas a two tendon lesion induces significant changes compatible with instability of the glenohumeral joint.

Adult↗
PubMed1992

[Studies using S-(+)-ketamine on probands. Endocrine and circulatory reactions, recovery and dream experiences].

UNLABELLED: Clinically used ketamine is a racemic mixture of two isomers, S(+)- and R(-)-ketamine. The anaesthetic potency of S(+)-ketamine was found to be three times higher than that of R(-)-ketamine. It was the aim of this study to compare the effects of racemic ketamine and S(+)-ketamine on endocrine and cardiovascular parameters, recovery and psychomimetic reactions in young healthy volunteers. METHODS: 6 women and 4 men between 23 and 38 years were investigated twice in a randomized double blind cross-over design receiving injections of 2 mg/kg BW racemic ketamine or 1 mg/kg BW S(+)-ketamine at an interval of at least 7 days. Samples were taken from a central venous catheter before and 1, 3, 5, 10, 15, 30, 60 and 120 min after injection for analysis of adrenaline, noradrenaline (by high pressure liquid chromatography with electrochemical detection), ADH, ACTH, cortisol (by radio immuno assay), glucose, lactate and free glycerol. In addition, SAP, HR, and arterial oxygen saturation were measured, and return of consciousness and orientation were protocoled. Incidence and assessment of dreams were reported by the volunteers. RESULTS: Adrenaline, noradrenaline, ACTH, cortisol, lactate and free glycerol in plasma as well as SAP and HR increased significantly after injection of both racemic ketamine and S(+)-ketamine. The influence on ADH and glucose was not significant. There were no differences between racemic ketamine and S(+)-ketamine in these parameters. Recovery was significantly improved after administration of S(+)-ketamine. Simple orders were followed after 7.9 +/- 1.1 vs. 9.2 +/- 1.2 min (P = 0.004). Orientation with respect to the person returned after 9.0 +/- 1.8 vs. 11.5 +/- 2.5 min (P = 0.004); with respect to time and location after 10.1 +/- 2.1 min vs. 13.4 +/- 4.0 min (P = 0.007). 18 dreams were reported; assessment was positive in 13 cases and indifferent in 5 cases, none was negative. In 7 of 10 cases, the investigators were able to identify that S(+)-ketamine had been injected. CONCLUSION: With respect to endocrine and cardiovascular parameters, the pharmacodynamic effects of racemic and S(+)-ketamine were comparable. Because of the significant improvement in recovery and the reduced quantitative drug load, S(+)-ketamine offers a clear clinical advantage compared with currently used racemic ketamine.

Adrenocorticotropic Hormone↗
PubMed1991

Isolation and partial characterization of circulating immune complexes in sera of children with HBV-mediated glomerulonephritis.

Circulating immune complexes (CIC) containing HBsAg and HBeAg were identified in sera of 5 out of 6 children with hepatitis B mediated membranous glomerulonephritis. CIC were precipitated from sera by 3.5% PEG, washed and subsequently analysed after acid dissociation and trypsin digestion. HBsAg, anti-HBs and albumin; HBeAg, anti-HBe and anti-HBc were recovered from the isolated complexes and these findings are discussed. Analysis of 3.5% PEG mediated precipitate of human serum proteins showed the relatively high content of IgG classical pathway complement components: C1q, C4 and C3.

Adolescent↗
PubMed1991

Characterization of erythrocytic glucose-6-phosphate dehydrogenase in a mouse strain with reduced G6PD activity.

Erythrocytic glucose-6-phosphate dehydrogenase (G6PD) of a mutant mouse strain with X-linked G6PD-deficiency was purified and compared with the wildtype G6PD by biochemical and physiological characteristics. The red cell G6PD activity of the mutant was 20% of the wildtype. The Michaelis constant (Km) of the substrate glucose-6-phosphate (G6P) was higher (90 microM) for the mutant than for the wildtype (56 microM). The isoelectric focusing with a pH range from 3 to 10 showed one more enzymatically active band for the wildtype G6PD compared to the mutant enzyme. Other enzyme characteristics, however, such as Km for nicotinamide adenine dinucleotide phosphate (NADP), utilisation of 2-deoxy-glucose-6-phosphate (2dG6P) and deamino-NADP, heat stability, pH optimum, molecular weight, and glucose metabolisation via the pentosephosphate pathway were similar in mutant and wildtype enzyme.

Animals↗
PubMed1990

Release and detection of dental corrosion products in vivo: development of an experimental model in rabbits.

An experimental animal model was developed to investigate the release of metal ions from nonprecious dental alloys. Cast specimens of five Ni-Cr-alloys and Co-Cr-alloys were implanted intramuscularly in rabbits for periods of 2, 4, 8, and 12 weeks. The concentrations of nickel, chromium, cobalt, and molybdenum in the implant-loaded muscles were determined by electrothermal atomic absorption spectrometry (AAS) and neutron activation analysis (NAA). Reference muscle samples of each animal were analyzed to determine the individual control values. Significant increases in the tissue concentrations of these metals occurred in the immediate vicinity of the implants. Concentration gradients of the corrosion products were found between the implant contact tissue and the implant periphery (p less than 0.001). Tissue concentrations of nickel and chromium correlated (r less than 0.7). Microprobe analysis before and after implantation of the alloy specimens indicated an even corrosive loss of the alloy surfaces and changes in the surface element distributions. Advantages and limitations of this animal model are discussed, as well as its application in future studies.

Animals↗
PubMed1990

[Vascular complications in free tissue transfers].

The causes of vascular complications after 306 cases of free vascularized tissue transfers were examined. The technique and success of the explorative operations were determined. The results show that 22 flaps were lost because of failures in indication, technique and monitoring. A no-reflow phenomenon was not observed.

Humans↗
PubMed1989

Calcium absorption from milk in lactase-deficient subjects.

Intestinal calcium absorption from milk containing lactose (+) and from another containing glucose (-) was studied in eight patients with normal lactase (NL) and seven lactase-deficient (LD) subjects to determine if lactase deficiency is implicated in Ca absorption. The results were compared with data obtained from Ca ingestion in a water solution. Ca absorption was measured by a double-isotope technique and the kinetic indices were obtained by a deconvolution method. With (-), Ca absorption was identical in NL and LD subjects and slightly higher than with water solution (15%, NS). With (+), Ca absorption in NL subjects was identical with that from water solution; in LD subjects it increased (23%, p less than 0.02). These data indicate that: Ca is absorbed equally well from milk as from water solution; (+) favors Ca absorption in LD subjects, which suggests that milk ingestion might be encouraged in LD subjects to avoid Ca deficiency; and (-) should be a valuable alternative for lactose-intolerant patients.

Animals↗
PubMed1989

[The spectrum of bacterial strains and problems of antibiotic prophylaxis in an intensive care unit].

Out of a total number of 1,935 patients of a mainly cardiac surgically orientated intensive care unit, 103 material extractions and 111 germ diagnoses with resistance examinations were carried out in 60 patients. The infection rate was 3.1%. Thirty-two of the 60 patients died (53.3%). Fifty-seven patients (95%) underwent open-heart surgery. With respect to the total number of open-heart operations (n = 1,345), the rate of severe infections was 4.23%. The germ spectrum reveals a predominance of "problem germs", especially pseudomonas and enterobacteria. The results of the resistance examinations show that no antibiotic combination is suitable for complete germ elimination. Cefotiam (halospor) is effective against 50% of the germs. Problems of an antibiotic prophylaxis are shown. Recommendations are given to restrict antibiotic prophylaxis to 24 hours perioperatively, preferably using a cephalosporin preparation.

Anti-Bacterial Agents↗