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Biomedical subjects

A Hahn

Publications and source records attributed to A Hahn.

At least 91 records · Page 5Linked to original sources
PubMed1995

Increased circulating soluble CD14 is associated with high mortality in gram-negative septic shock.

The soluble glycoprotein sCD14 binds lipopolysaccharide, a complex that activates endothelial cells and that may be crucial in gram-negative sepsis. Therefore, serum sCD14 was analyzed in 54 patients with gram-negative septic shock and in 26 healthy controls. sCD14 was tested by ELISA and Western blotting. Patients had higher sCD14 concentrations than controls (median, 3.23 vs. 2.48 micrograms/mL, P = .002). Increased levels were associated with high mortality (median, 4.2 micrograms/mL in nonsurvivors vs. 2.8 micrograms/mL in survivors, P = .001). sCD14 was found in two isoforms (49 and 55 kDa) in monocyte cultures. In sera only one of either form was detectable. Controls had the 49-kDa form, and patients had either the 49- or 55-kDa form, but patients with high levels of sCD14 had only the 55-kDa form. Twenty-one (53%) of 39 with the 55-kDa form and 8 (57%) of 14 with the 49-kDa form died. Thus, the level of sCD14 but not its biochemical form had a prognostic value in patients with gram-negative septic shock.

Adolescent↗
PubMed1995

Neurootologic findings in patients with so called Menière-like disease.

A group of 150 patients was clinically observed using a complete battery of neurootological methods. The patients were believed to suffer from Menière's disease (MD). After taking anamnestic data [NODEC III] and performing calorimetry, cranio-corpo-graphy and audiology tests we could confirm a former established diagnosis of MD in a few cases only.

Adult↗
PubMed1995

Production of polyclonal and monoclonal antibodies against hyphae from arbuscular mycorrhizal fungi.

Polyclonal and monoclonal antibodies were produced against hyphae of the arbuscular mycorrhizal fungus Glomus monosporum. The polyclonal antibodies (pAbs) were raised in a rabbit by immunizing with hyphae. They were tested for their specificity by a dot-immunoblot assay (DIBA). After the third immunization, a distinct difference in the signal strength was observed between the antisera and the preimmune serum. The pAbs showed cross-reactions to a number of fungal species, both mycorrhizal and other. For the production of monoclonal antibodies (mAbs), mice were immunized intraperitoneally with hyphae. The resulting hybridoma cell culture supernatants were tested by an indirect immunolabeling procedure. For this purpose the hyphae were immobilized on silane-coated microscopic slides. The mAb 8A7 reacted with hyphae from all Glomus isolates tested so far. Cross-reactivities were not observed with hyphae from fungi of the family Acaulosporaceae, phytopathogenic fungi tested so far, or from spores from Glomus species.

Animals↗
PubMed1994

Activation of phosphoinositide catabolism and DNA synthesis in vascular smooth muscle cells by LDL and positively charged proteins: evidence that effects of LDL are not specifically dependent on the polycationic nature of apo B.

We have investigated whether the polycationic structure of apo B is an important determinant for the recognition of low density lipoprotein (LDL) by putative signalling-coupled/growth receptor(s). Using cultures of human vascular smooth muscle cells (VSMC), the effects of LDL on phosphoinositide (PI) catabolism and DNA synthesis have been compared with those of a variety of proteins which, like apo B, possess a strong positive charge. Using myo-[2-3H]-inositol-prelabelled VSMC, the polycationic proteins protamine and histones II-S, III-S, V-S and VII-S, but not low-molecular weight polyamines (putrescine and spermine), were found to stimulate PI catabolism in a dose- and time-dependent manner. In contrast to LDL which induced rapid, transient increases in inositol tris- and bis-phosphates and a delayed sustained increase in inositol monophosphate, the PI response of VSMC to polycationic proteins was characterized by a potent, sustained increase in inositol bisphosphate and the absence of an inositol trisphosphate transient. Heparin inhibited the PI catabolic response of VSMC to histones and protamine but was without effect on LDL-stimulated PI catabolism. Like LDL, polycationic proteins also stimulated DNA synthesis in VSMC (incorporation of [3H]-thymidine). The data indicate that signalling/growth effects of LDL and positively charged protein occur via distinct mechanisms and that the effects of LDL do not primarily depend upon the polycationic properties of apo B.

Apolipoproteins B↗
PubMed1994

Rapid postabsorptive metabolism of nicotinic acid in rat small intestine may affect transport by metabolic trapping.

Postabsorptive metabolism of [3H]nicotinic acid by rat proximal jejunum was studied in vitro using the everted sac technique and in vivo by applying ligated loops. Metabolites were analyzed by HPLC with radiochemical detection. Within 60 min of incubation nicotinic acid was almost completely metabolized in vivo. Only 3.2% of the label could be detected in the original substrate nicotinic acid, whereas > 90% of the radioactivity present in the gut wall was nicotinamide. Further in vitro experiments revealed that conversion was rapid; after 10 min of incubation > 40% of the substrate was converted to other metabolites. From analysis of the serosal fluid, it was evident that only nicotinic acid and nicotinamide were transferred to the serosal compartment. Rapid conversion of nicotinic acid might affect the transport step itself by metabolic trapping, resulting in the maintenance of a substrate gradient necessary for passive absorption. In contrast, as examined by gradient centrifugation, the substrate in subcellular organelles is transferred only to a minor extent.

Animals↗
PubMed1993

Insulin influences immunoreactive endothelin release by human vascular smooth muscle cells.

This study sought to investigate whether insulin influences immunoreactive endothelin release from cultured human vascular smooth muscle cells. For this purpose, we incubated cultured vascular smooth muscle cells (VSMC) obtained from human microvessels with 0, 80, and 320 microU/mL insulin with or without arginine vasopressin (10 nmol/L) and angiotensin II (10 nmol/L). After 6 hours, the culture supernatant was collected and immunoreactive endothelin was determined by radioimmunoassay. Insulin at a concentration of 320 microU/mL induced a significant increase of immunoreactive endothelin levels in medium (from 15.2 +/- 0.8 to 20.6 +/- 0.8 pg/200 microL, P < .01) and potentiated arginine vasopressin- and angiotensin II-induced immunoreactive endothelin release (P < .0001 and P < .04, respectively). Insulin at a concentration of 80 microU/mL did not induce a significant increase of spontaneous immunoreactive endothelin release, but significantly increased the effects of arginine vasopressin (P < .05). In conclusion, insulin influences immunoreactive endothelin release from human VSMC in culture.

Angiotensin II↗
PubMed1992

Coordinate genetic control of yeast fatty acid synthase genes FAS1 and FAS2 by an upstream activation site common to genes involved in membrane lipid biosynthesis.

A systematic search for upstream controlling elements necessary for efficient expression of the yeast fatty acid synthase genes FAS1 and FAS2 revealed identical activation sites, UASFAS, in front of both FAS genes. The individual element confers, in a heterologous yeast test system, an approximately 40-fold stimulation of basal gene expression. The UASFAS motifs identified have the consensus sequence TYTTCACATGY and function in either orientation. The same sequence motif is found in the upstream regions of all so far characterized yeast genes encoding enzymes of phospholipid biosynthesis. In gel retardation assays, a protein factor, Fbf1 (FAS binding factor), was identified which interacted with UASFAS. The UASFAS motif proved to be an inositol/choline responsive element (ICRE) conferring strict repression by exogenous inositol and choline on a heterologous reporter gene. Its core sequence perfectly matches the CANNTG motif typical of basic helix-loop-helix DNA-binding proteins. In contrast to the individual UASFAS element, the intact yeast FAS promoters are not significantly influenced by inositol and choline, and thus allow nearly constitutive fatty acid synthase production. Available evidence suggests that additional cis- and trans-acting elements, other than UASFAS and Fbf1, are involved in this constitutive FAS gene expression.

Base Sequence↗
PubMed1992

High-performance liquid chromatographic determination of biotin in biological materials after crown ether-catalyzed fluorescence derivatization with panacyl bromide.

This paper reports a high-performance liquid chromatographic (HPLC) technique to determine biotin in biological samples. Biotin and the internal standard dethiobiotin are converted into fluorescent derivatives by using panacyl bromide [p-(9-anthroyloxy)phenacyl bromide] as a fluorescence label. Biotin is extracted from biological tissue with trichloroacetic acid and the extract is purified by a combination of solid-phase extraction on C18 cartridges, ion-exchange chromatography on DOWEX formate resin, and thin-layer chromatography. The purified sample extract is derivatized in the presence of a crown ether. The resulting panacyl esters can be separated on reversed-phase as well as on normal-phase HPLC. Normal phase HPLC is preferable because it provides higher sensitivity and demands less sample pretreatment. Analysis of rat intestinal tissue revealed that only about 13% of the biotin is present in free form whereas 87% is bound in proteins from which it can be released by hydrolysis. Biotin values determined by this method are comparable to those obtained by other techniques.

Acetophenones↗
PubMed1992

Identification of a new DMD gene deletion by ectopic transcript analysis.

The detailed genetic analysis of the Duchenne/Becker muscular dystrophy gene is hindered by the large number of exons involved and their separation by huge introns. These problems can be overcome by the analysis of mRNA rather than genomic DNA and ectopic transcripts derived from peripheral blood lymphocytes provide a convenient source of material. Using reverse transcription and nested PCR, we show here a comprehensive strategy for the rapid and complete analysis of the coding sequences from complex genes and illustrate its potential by the identification of a hitherto undescribed single exon deletion.

Base Sequence↗
PubMed1992

Hereditary sensory radicular neuropathy: defective neurogenic inflammation.

Hereditary sensory radicular neuropathy exhibits autosomal dominant inheritance with complete penetrance in males and incomplete penetrance in females. Newer tests of small sensory nerve function were used in screening 8 family members aged between 14 and 66 years. All exhibited some frequent features of the disorder with an onset in the 2nd or 3rd decade, foot ulceration, foot callus, loss of pin prick, thermal and light touch sensation, and some reduction in vibration acuity and proprioception in the lower limbs. The hands were involved in 3 of 8, muscle involvement was present in 5 of 8, but deafness was not detected by audiometry. Nerve conduction velocity, sensory action potentials, latency and amplitude, thermal acuity, vibration acuity and axon reflex flares were measured in all patients. One sural nerve biopsy confirmed the presence of peripheral fibre loss in this predominantly sensory neuropathy. Chemically evoked axon reflex tests were used to evaluate the extent of primary sensory nerve fibre involvement. All patients were tested using a Moor MBF 3-D dual channel laser Doppler velocimeter. Acetylcholine or phenylephrine iontophoretically applied as 16 mC doses evoked absent or tiny axon reflexes in areas of impaired pin prick sensation. By contrast, direct microvascular dilator responses to nitroprusside (smooth muscle dependent) and acetylcholine (endothelium-dependent) were present but somewhat reduced in areas with defective neurogenic inflammation. These results differ significantly from the responses obtained in age-matched healthy controls (P < 0.05). Foot pressure analysis was performed for orthoses in 2 affected members with foot ulceration using the Musgrave Footprint system.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Optimized high-performance liquid chromatographic procedure for the separation and determination of the main folacins and some derivatives. II. Extraction method and application to rat liver.

Different methods for the extraction of folacins from biological materials and the hydrolysis of pteroylpolyglutamates prior to high-performance liquid chromatography were investigated. Acetone precipitation of proteins led to higher extraction rates of folates from biological materials as examined by using an endogenous labelling technique. It also caused less destruction of some folates but could not be combined with subsequent hydrolysis of pteroylpolyglutamates. Pteroylpolyglutamates were hydrolysed by a partially purified suspension of pteroylpolyglutamates hydrolase (PPH). Comparative studies on the folate content of rat liver revealed that complete hydrolysis of polyglutamates could also be achieved by incubating the homogenized tissue at 37 degrees C to allow endogenous PPH to act. This procedure causes interconversions of folates and is therefore not suitable for the analysis of biological materials.

Animals↗
PubMed1991

Transport of pteroylglutamic acid into brush border membrane vesicles from rat small intestine is a partially carrier-mediated process.

Intestinal transport of PteGlu was studied using BBMV from rat small intestine. Transport was neither coupled to a specific cation gradient nor was it influenced by variations of the membrane potential. In the presence of a transmembrane pH gradient (pHout less than pHin) initial transport was significantly higher compared to studies without pH gradient. Under these conditions transport could be inhibited by pretreating the vesicles with DIDS, an inhibitor of anion exchange systems. Uptake of PteGlu could not be enhanced by preloading the BBMV with HOP4(2-) and Cl- and was not sensitive to DIDS under these conditions. Uptake studies using different concentrations of PteGlu revealed dual transport kinetics in the presence of a pH gradient and linear uptake in its absence. It could be concluded that uptake is mediated by a PteGlu-/OH(-)-antiporter at low substrate concentrations and occurs by non-ionic diffusion at higher concentrations or in the absence of a pH gradient. In an additional series of experiments it could be shown that about one-third of the substrate is bound to the membrane and is not transported. The biological significance of this binding remains unclear.

Animals↗
PubMed1991

Epilation of upper lip hirsutism with a eutectic mixture of lidocaine and prilocaine used as a topical anesthetic.

Twenty-one patients were included in a double-blind, placebo-controlled, cross-over study with a eutectic mixture of lidocaine and prilocaine (EMLA). EMLA or placebo was placed on the upper lip for 1 hour; diathermy was then performed for 10 minutes. The pain caused by diathermy was evaluated by the patients and the cosmetologist on a four-point scale. The results of the investigation showed that there was significantly less pain after application of 5 gm of EMLA cream on the upper lip than after application of placebo, assessed both by the patient and by the cosmetologist. Eighteen of 20 patients preferred EMLA (p less than 0.0001). Local reactions were few and mild.

Adult↗
PubMed1991

Cranio-corpo-graphy. A neurootological screening test.

Cranio-corpo-graphy affords a photographic representation of the patient's "radar-like" movement patterns as he performs the standing (Unterberger, Fukuda) and stepping (Romberg) tests. Of the various parameters used for analysis, a wide angular deviation, i.e., where the patient deflects more than circa 60 degrees away from the sagittal axis, is taken to signify a peripheral dysfunction, usually involving the side of deviation. In addition, broad lateral sway values and standing tests sways suggest a central pathology. In this study, three data banks were created. One consisting of 500 patients tested in our department over the last ten years, all showing a normal cranio-corpo-graphic pattern; the second made up of 500 patients showing a clear peripheral pattern, i.e., abnormal angular deviation with normal sway values and the third (650 patients) with a typical central disturbance, i.e. a broad lateral sway. These groups were then submitted to a detailed statistical analysis.

Adult↗