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Biomedical subjects

J Weber

Publications and source records attributed to J Weber.

At least 649 records · Page 36Linked to original sources
PubMed1982

High-affinity binding of ADP and of ADP analogues to mitochondrial F1-ATPase.

Nucleotide-depleted F1-ATPase was prepared from beef heart mitochondria. By use of fluorescence techniques and isotope binding analyses, we investigated the occupation of the high-affinity binding sites on F1 by ADP and the ADP analogues 3'-O-(1-naphthoyl)adenosine diphosphate (N-ADP) and 3'-O-[1-(5-dimethylamino)-naphthoyl]adenosine diphosphate (DMAN-ADP). F1-ATPase was found to exhibit three binding sites for ADP (Kd = 50 nM for one site; Kd = 3 microM for the remaining two sites), two binding sites for N-ADP (Kd = 20 - 50 nM for both of the sites), and three binding sites for DMAN-ADP (Kd = 50 nM for all of the sites). Since the adenine nucleotides under consideration are bound to the same class of sites, the binding data can be explained best on the basis of the hypothesis that the binding process is anticooperative with ADP, whereas the analogues are able to overcome anticooperativity partially (N-ADP) or completely (DMAN-ADP). This binding model is consistent with the view that the exchangeable tight sites are involved directly in the catalytical process of ATP-synthesis in oxidative phosphorylation.

Adenosine Diphosphate↗
PubMed1982

Adenoassociated virus has a unique chromatin structure.

The organization of intranuclear adenoassociated virus DNA (AAV) was examined following micrococcal nuclease digestion of nuclei prepared from cells coinfected with AAV type 2 (AAV-2) and adenovirus type 2 (Ad2). Blot-hybridization analysis of the DNA with AAV-2, Ad2, and cellular DNA probes revealed that AAV-2 chromatin has a unique structure, which upon nuclease digestion gives rise to a smear of oligomeric DNA fragments from 600-2200 base pairs in length with only a very faint band about 160 base pairs and no discrete multimers. This structure was similar to, but distinguishable from, Ad2 chromatin and completely unrelated to eukaryotic chromatin.

Adenoviruses, Human↗
PubMed1982

[Biology and surgery of small cell bronchial cancer].

The small cell type is encountered in 10 per cent of all operations for lung cancer. It is centrally localised in about 70 per cent, thus pneumonectomy has to be performed as long as the tumour is operable. If the operation is performed as long as lymph node metastases are absent the 5 year survival rate comes up to 39 per cent. This result is in favour of surgery. The 5 year survival rate of all resected cases of small cell carcinomas amounts to about 18 per cent. Paraneoplastic symptoms are rare, they could only be traced in a percentage of 4.5 (n = 389).

Adult↗
PubMed1982

[Comparison of commercially available radioimmunoassays for the determination of bile acids in serum (author's transl)].

Three commercially available radioimmunoassays for the determination of bile acids in serum were evaluated with respect to specificity and precision. The SLCG-radioimmunoassay (Abbott) measures chiefly cholic acid conjugates, and the CBA-radioimmunoassay (Becton-Dickinson) measures all conjugated bile acids, with an over-response to taurine metabolites. With respect to cross reactions, the performances of the CG-and the CBA-radioimmunoassays differed significantly from those stated by the manufacturers, the former showing a 32% response to taurocholic acid, the latter responding only 118% to taurochenodeoxycholic acid. At physiological concentrations of albumin + globulin, the recovery of defined cholanic acids was 85-101%. Good reproducibility was shown by the CG-radioimmunoassay in the range 0.5-10.0 mumol/l, by the CBA-radioimmunoassay in the range 1.0-25.0 mumol/l, and by the SLCG-radioimmunoassay in the range 0.5-3.0 mumol/l. There were no important differences in the inter-and intra-assay precision of the three methods.

Antibody Specificity↗
PubMed1982

[Conjugated bile acids and sulphated glycolithocholic acid in the serum of healthy probands (author's transl)].

Using commercially available radioimmunoassays, bile acids were measured in the serum of 378 healthy probands. The following values were found: conjugated cholic acid 0.36 +/- 0.38 mumol/l (95% percentile 1.28 mumol/l) (CG-radioimmunoassay from Abbot); sum of the various conjugated cholanic acids 2.8 +/- 1.58 mumol/l (95% percentile 5.98 mumol/l) (CBA-radioimmunoassay from Becton-Dickinson); sulphate glycolithocholic acid 0.57 +/- 0.33 mumol/l (95% percentile 1.23 mumol)l) (SLCG-radioimmunoassay from Abbot). The values showed a normal logarithmic distribution. No sex-specific differences were found between similar age groups of the 207 male and the 171 female probands. In 50 probands, serum concentrations were followed over a period of 3 hours after a standardized meal. Conjugated cholic acid showed a 5-fold postprandial increase, compared with the concentrations measured in fasting probands. In 48% this maximum was reached within 60 minutes, in 32% within 2 hours, and in 20% within 3 hours. The concentrations of sulphate glycolithocholic acid were subject to only slight postprandial variations, which did not appear until the second or third hour.

Adult↗
PubMed1982

[Comparative studies on serum bile acid concentrations before and after cholecystectomy].

In 15 patients without liver disease fasting and postprandial serum bile acid concentrations are determined before and 2-4 weeks after cholecystectomy. In every case a standardized test meal is given and conjugates of cholic acid and chenodeoxycholic acid are measured by radioimmunoassay. The increase of serum bile acid concentrations for three hours after ingestion of the test meal is not diminished by cholecystectomy. In comparison to 50 healthy volunteers and 25 additional cholecystectomized persons there are no differences in the area under the concentration-time curve. From these results it is concluded that the postprandial serum bile acid level is determined by the enteral liberation of bile acids rather than by gallbladder contraction.

Adult↗
PubMed1981

Plasma catecholamines, noradrenaline metabolism and vascular response in desoxycorticosterone acetate hypertension of rats.

Mineralocorticoid hypertension was induced in male Wistar rats by the injection of desoxycorticosterone acetate (DOCA) in oily solution (2 X 5 mg/kg daily for 7 days) and of desoxycorticosterone trimethylacetate in a microcrystalline suspension (15 mg/kg every third day for 4 weeks). A 1% NaCl solution or demineralized water was given as drinking fluid. Four weeks after the beginning of treatment, mean arterial blood pressure was 161 +/- 3.8 mmHg in DOCA-saline treated and 140 +/- 5.9 mmHg in DOCA-water-treated rats. Basal plasma levels of noradrenaline and adrenaline did not differ in conscious, unrestrained DOCA-treated rats and in control rats 3, 7 and 28 days after the beginning of hormone administration. Furosemide (50 mg/kg) caused within 30 min the same degree of diuresis and natriuresis in DOCA-treated and in control rats, but the plasma noradrenaline concentration in DOCA-treated rats rose to a higher level than in the controls. The isolated perfused hearts of rats which received DOCA for 7 and 28 days, respectively, had a reduced uptake of [3H]noradrenaline as compared to the controls. In isolated perfused hindlimb preparations from rats which had received DOCA for 7 days, the dose-response curve to noradrenaline but not that to KCl was shifted to the left. However, when DOCA and saline were given for 28 days, besides a higher sensitivity to noradrenaline an increased maximum response was observed with both noradrenaline and KCl. It is concluded that adrenergic tone is enhanced during the development of DOCA hypertension. Since the changes in the sympathetic nervous system in DOCA-water-treated rats, which had a less pronounced hypertension, were similar to those in DOCA-NaCl-treated rats, alterations in adrenergic vascular tone were not directly related to the level of the blood pressure.

Animals↗
PubMed1981

Nuclear ribonucleoprotein particles from adenovirus infected Hela cells.

Heterogenous nuclear RNA-protein complexes (hnRNP) from adenovirus-2 (Ad-2) infected Hela cells contain most of the virus-specific RNA which is labeled in the nucleus during periods lasting from 45 seconds to 2 hours. Moreover, the percentage of RNA which is Ad-2 specific as monitored by filter hybridization increases progressively from early to late period where it accounts for as much as 50-60% of the labeled RNA. The Ad-2 sequences are found in heterogenous complexes sedimenting between 30 and 200 S the density of which in CsCl (rho approximately 1.39) as well as metrizamide (rho approximately 1.29) seems to be the same as that of the bulk particles. A more detailed analysis with restriction fragments shows that all regions of the Ad-2 genome are represented in these particles.

Adenoviridae↗
PubMed1981

[Thrombolytic treatment of venous thrombi with combined use of streptokinase and human plasminogen (author's transl)].

Thirteen patients with up to two-week-old phlebothromboses were treated with streptokinase and human plasminogen according to a fixed dosage scheme. In six cases reopening of the vein was complete, in three cases partially complete. In four cases thrombolysis had to be stopped due to macrohaematuria. Haemorrhagic complications occurred mainly after the third day of treatment. Substitution of human plasminogen during continuous streptokinase administration is, in the case of demonstrable lowering of the plasma plasminogen level, a valuable addition to the thrombolytic concept.

Adolescent↗
PubMed1981

[Visual evoked responses with flash pattern in normal subjects (author's transl)].

Visual evoked responses to flash pattern simulations have been observed in young healthy adults. Stimulations of whole visual fields (37 subjects) and half-fields (11 subjects) have been performed. These responses are reproductible from one subject to another and show very clear waves in the occipital and central regions. On central leads, whatever the stimulation (stimulation of total visual fields or half-fields), the responses are always the same: a negative peak at 70 msec. followed by a positive peak at 90 msec, then a negative peak at 116-120 msec. On occipital leads, stimulation of the whole visual field shows a diphasic response: a positive wave at 100 msec and a negative wave at 140-150 msec. However, half-field stimulation shows different responses on the ipsi- and contralateral hemispheres, with a disappearance of the positive 100 msec wave in the ipsilateral occipital region. Thus, flash pattern stimulations seem to be useful in clinical practice because they evoke different types of responses in occipital and central regions.

Adult↗
PubMed1981

Adenovirus-induced mutations at the hypoxanthine phosphoribosyltransferase locus of Chinese hamster cells.

Hpt-13 is a Chinese hamster cell line deficient in hypoxanthine phosphoribosyltransferase (EC 2.4.2.8) and sensitive to a medium containing 10(-4) M hypoxanthine, 5.5 X 10(-6) M aminopterin, and 10(-4) M thymidine. In this cell line there is a high incidence of cells resistant to this selective medium after an incubation with either ethyl methane sulfonate or adenovirus type 2 complete virions or their incomplete particles. The rate of reversion in the presence of these agents was 34-fold higher with ethyl methane sulfonate and 2.5- to 5.6-fold higher with adenovirus particles than the spontaneous rate of reversion. The revertant phenotypes were stable for many generations without selective pressure. All of the revertants tested recovered the hypoxanthine phosphoribosyltransferase activity. Most of them, however, carried an enzyme of lower activity and faster electrophoretic mobility than that of the wild type. The preferential reversion to this type of enzyme was observed among spontaneous revertants as well as among those induced by mutagenesis with ethyl methane sulfonate or exposure to viral particles. Our results suggest that adenovirus particles and ethyl methane sulfonate induce mutations at the hpt locus of Hpt-13 cells through similar mechanisms.

Adenoviruses, Human↗
PubMed1981

[The value of angiography, sonography and computed tomography in follow-up studies after palliative renal tumour embolization (author's transl)].

Palliative transcatheter tumour embolization was performed in 40 patients having non-operable renal carcinoma using particulate, semiliquid and liquid embolizing substances. In addition the Gianturco-Andersen-Wallace (GAW) coil was applied in 7 patients showing remarkable vascular recanalization. Effects of the angiotherapeutic procedures were controlled by re-angiography in 33 cases. Sonography was performed in 15 cases and computed tomography in 24 patients before and after embolization. It was found that the re-angiography was necessary: a) as thhe first control to prove the extension of thrombotic obstruction and to assess the remaining collateral circulation; b) as an indication for re-embolization in 7 cases showing remarkable recanalization. Follow-up computed tomography and sonography helped to observe the long-term changes: shrinkage of the tumour and the embolized kidney, and recurrence of the tumor growth or local retroperitoneal and liver metastases. The analysis of our observations confirms the value of re-angiography for the short-term follow-up study. Sonography and computed tomography are reliable procedures for the further follow-up of patients.

Adenocarcinoma↗
PubMed1981

[Angiotherapeutic embolization of the internal iliac arteries in recurrent bleeding of the urinary bladder using balloon-tipped catheters (author's transl)].

In 9 patients having carcinoma of the urinary bladder and recurrent untreatable hematuria (n = 5), cystitis following radiation-therapy (n = 3) or Endoxan-Cystitis (n = 1), a transcatheter palliative embolization was performed. By aid of the flow guided transport of balloon-tipped catheters both internal iliac arteries were occluded via the transfemoral route in one session under local anaesthesia. The following embolizing substances were used: particulate Fibrospum und Tachotop and the semiliquid aminoacid Ethibloc. Safe embolization was obtained under protection of the inflated Latex balloon and by insertion of via a catheter sheath introducing system. A painless angiographic documentation during and after angiography was obtained using a new low osmolar contrast medium.

Aged↗