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R Schmitt

Publications and source records attributed to R Schmitt.

At least 19 recordsLinked to original sources
PubMed1992

The nitrate reductase-encoding gene of Volvox carteri: map location, sequence and induction kinetics.

The nitrate reductase (NR) structural gene (nitA) of Volvox carteri has been cloned and characterized. There is a single copy of this gene in the genome, and RFLP (restriction-fragment length polymorphism) analysis assigns it to the previously defined nitA/chlR locus on linkage group IX, 20-30 cM from the two beta-tubulin-encoding loci. Determination of the 5871-nt sequence of the coding region of genomic clones, and comparisons to a cDNA sequence, revealed ten introns and eleven exons that encode a 864-aa polypeptide. Detailed comparisons with higher-plant and fungal NRs indicate that, whereas the aa sequence is strongly conserved within functional domains for the flavin adenine dinucleotide-, heme- and molybdenum-pterin cofactor-binding sites, substantial differences in the aa sequence occur in the N-terminal end and the two inter-domain regions. Two potential transcription start points 439 and 452 nt upstream from the start codon and a polyadenylation signal 355 nt downstream from the stop codon have been identified by primer-extension analysis and cDNA sequencing, respectively. Accumulation of the nitA transcript is both induced by nitrate and repressed by ammonium and urea: after the organism is transferred from ammonium to nitrate as the nitrogen source, a 3.6-kb NR transcript is readily detectable on Northern blots by 10 min, reaches maximum abundance by 30 min, and then rapidly declines to an intermediate level that is subsequently maintained. Substantial induction by nitrate is observed at the end of the dark portion of the daily light/dark cycle, but the inductive response peaks in the first hour of the light period.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1992

The yptV1 gene encodes a small G-protein in the green alga Volvox carteri: gene structure and properties of the gene product.

Small G-proteins encoded by ras-like genes are ubiquitous in eukaryotic cells. These G-proteins are believed to play a role in central processes, such as signal transduction, cell differentiation and membrane vesicle transport. By screening genomic and cDNA libraries of the colonial alga, Volvox carteri f. nagariensis, with ypt DNA probes from Zea mays, we have identified the first member of a ypt gene family, yptV1, within a green alga. The 1538-bp yptV1 gene of V. carteri consists of nine exons and eight introns and has three potential polyadenylation sites 210, 420 and 500 bp downstream from the UGA stop codon. The derived 203-amino-acid polypeptide, YptV1, exhibits 81% similarity with Ypt1 from mouse, with the corresponding genes sharing four identical intron positions. Recombinant YptV1 (reYptV1) produced in Escherichia coli retains the ability to bind GTP after SDS-PAGE and immobilization on nitrocellulose. Immunological studies using polyclonal antibodies against reYptV1 indicate that the protein is present in the membrane fraction of a V. carteri extract and is expressed throughout the whole life-cycle of the alga. Similar to other Ras-like proteins, YptV1 contains two conserved C-terminal cysteine residues suggesting post-translational modification(s), such as isoprenylation or palmitoylation, required for membrane anchoring. The presumptive role of YptV1 in cytoplasmic vesicle transport is briefly discussed.

Amino Acid Sequence↗
PubMed1992

Complete nucleotide sequence of Tn1721: gene organization and a novel gene product with features of a chemotaxis protein.

The complete 11,139-nucleotide sequence of transposon Tn1721 has been determined. It contains three 38-bp inverted repeats, and (in this order) a new orfI, a resolution site (res), genes encoding resolvase (tnpR), transposase (tnpA), tetracycline-resistance (TcR) repressor (tetR), TcR (tetA) and a truncated transposase gene (tnpA'). The modulator origin of Tn1721 from at least three separate sources is supported by the distinctive codon usages of orfI, tnpR/tnpA and tetR/tetA, and by sequence similarities with Tn501 (tnpR/tnpA) and RP1 (tetR/tetA). The ORFI-encoded 56-kDa polypeptide exhibits features of a methyl-accepting chemotaxis protein (MCP) with a conserved signal domain and a potential transmembrane domain; this polypeptide cross-reacts with anti-MCP antiserum. Like chemotaxis genes, orfI is transcribed from a sigma 28-like promoter. The overexpressed orfI gene product interferes with MCP-dependent chemotaxis suggesting that it completes for soluble transducer protein(s) in the cell. The potential selective advantage of this novel transposon-borne gene is discussed.

Amino Acid Sequence↗
PubMed1992

Botryozyma nematodophila gen. nov., spec. nov. (Candidaceae).

The new genus Botryozyma with a single species, B. nematodophila is proposed for two isolates from nematodes (Panagrellus zymosiphilus) occurring in grapes with sour-rot. The new genus has typical ascomycetous characteristics and, being unable to produce ascospores, is placed in the family Candidaceae.

Animals↗
PubMed1992

Hemodynamic and humoral effects of the novel calcium antagonist Ro 40-5967 in patients with hypertension.

The tolerability and hemodynamic and humoral effects of the structurally novel calcium antagonist Ro 40-5967 were investigated in 64 patients with hypertension. In a double-blind, placebo-controlled study, ascending oral doses of 50, 100, 150, or 200 mg were administered once daily for 8 days in a solution. Ro 40-5967 was well tolerated up to 150 mg, but treatment was stopped in one patient in the 200 mg group because of bradycardia. Blood pressure was dose-dependently reduced over the full 24-hour dosing period with more pronounced effects on day 8 than on day 1. The maximum blood pressure reduction was obtained after 150 mg (supine blood pressure, -34/-25 mm Hg, p less than 0.001). Despite a slight decrease in supine heart rate, cardiac output increased. PQ time was dose-dependently increased and concentration-effect analysis showed that relevant atrioventricular conduction disturbances occur only at concentrations much higher than those required to reduce blood pressure. Changes in catecholamines, plasma renin activity, and aldosterone were small and inconsistent. In conclusion, Ro 40-5967 has a long-lasting antihypertensive effect after once-daily administration.

Aldosterone↗
PubMed1992

[The preoperative marking of nonpalpable breast lesions: the technic and results].

189 non-palpable breast lesions in 182 patients were localized using conventional mammographic apparatus, a wire grid compression plate and a cannula with a hooked mandrin. The technique of the examination for defining the lesion in three planes and fixation of the lesion with the wire is described. In 173 instances (91.5%), the lesion was found at the first biopsy and subsequent biopsies were necessary on only 24 occasions. One lesion (0.5%) was missed completely. 47 carcinomas were found (24.9%) and the incidence of malignancy increased from 14.3% to 33.3% during the series. The mean ratio defining the size of the biopsy and the size of the lesion was 3.3 and indicates good preservation of breast tissue. Radiographs of the specimen taken with compression showed 186 lesions (98.4%). The method, which is comfortable for the patient, provides satisfactory detection and localization of the lesions; results are similar to those of stereotactic methods but this method is quicker and much less expensive.

Adult↗
PubMed1992

Computed tomography of bronchogenic carcinoma: findings and reevaluation after radiotherapy.

493 computed tomograms were performed in 150 patients with bronchogenic carcinomas after radiotherapy. In early controls after termination of the irradiation, tumors with atelectasis could be delineated slightly better. In tumors without atelectasis, however, delineation deteriorated. In 50 late controls the radiation-induced pulmonary injury resulted in further masking of the tumor area, independent of the initial degrees of airway obstruction. Post-radiation changes were always earlier and more extensively visible by CT than by conventional radiography. No radiation effect on delineation of the mediastinal lymph nodes was provable. In 87% of all cases the remission rate of the tumors could be adequately evaluated by CT. In 43% of the late controls a delayed complete remission was seen. Fifteen out of 20 tumor recurrences or progressions were recognizable only by CT. The most important diagnostic criteria after radiotherapy of bronchogenic carcinomas are: 1. Consideration of the irradiation modalities and timing of the CT examination. 2. knowledge about the course of the pulmonary reaction to irradiation and 3. subtle comparisons of serial CT examinations in tumor follow-up.

Adult↗
PubMed1992

Protein synthesis in skeletal muscle of uremic patients: effect of low-protein diet and supplementation with ketoacids.

The purpose of this study was to investigate the modifications of muscle protein synthesis activity in uremic patients fed a low-protein diet and a low-protein diet supplemented with a keto acid-amino acid mixture. The protein synthesis activity was evaluated in vitro on isolated muscle ribosomes incubated in a cell-free medium with tritiated leucine. Simultaneously, nitrogen kinetics and amino acid patterns were examined. Protein synthesis activity is correlated with the protein content of the diet in uremic patients. The keto acid-amino acid supplementation enhances protein synthesis. Variations of protein synthesis can be correlated with the variations of nitrogen balance which implies a major role of protein synthesis activity in muscle protein metabolism. Variations in plasma levels of the essential amino acids, mainly leucine and valine, can be correlated with the variations of protein synthesis activity, and these amino acids seem therefore to be mediators of the dietary effects on protein synthesis in uremia.

Aged↗
PubMed1992

[Technical problems during coronary revascularization in case of massive calcified aorta].

A massively calcified ascending aorta which may make aortic clamping impossible, is a major obstacle to coronary revascularisation surgery. The aim of this study was to demonstrate that by the use of certain technical modifications, these patients can be treated even in multivessel disease. In the author's experience, two patients with this condition underwent complete revascularisation with a good surgical result controlled by angiography. The sites of arterial cannulation were the aortic arch in one case, the brachiocephalic artery and the common femoral artery in the other case. The ascending aorta was not clamped in either patient or used as the origin of the coronary bypass grafts. Myocardial protection was performed by systemic cooling with ventricular fibrillation without cardioplegia. The feasibility of these methods has led to the suggestion of a classification of the aortic wall according to peroperative palpation. This classification would provide indications for the use of technical modifications not only in extreme cases of aortic calcification but also in patients with severe atherosclerotic changes at high neurological risk; it would not, however, interfere with the classical technique of revascularisation.

Aged↗
PubMed1992

New technique for genetic amniocentesis in twins.

A new technique is described for amniocentesis in twins. Using a curvilinear or linear transducer, the separating membrane and an adjacent pocket of amniotic fluid in each cavity are simultaneously visualized. An amniocentesis needle is advanced into the first cavity. A second needle is introduced into the other amniotic cavity without altering the position of the transducer. This technique permits visualization of both needles simultaneously, providing proof of proper placement of the needle in each cavity. The advantages are unambiguous evidence of correct sampling of each cavity and lack of necessity for injection of a foreign substance into the amniotic sac. Finally, hard-copy documentation of proper needle placement is generated for the records. This procedure has been performed in seven twin sets with good results and patient acceptance.

Amniocentesis↗
PubMed1991

Plant biochemistry of xenobiotics: isolation and properties of soybean O- and N-glucosyl and O- and N-malonyltransferases for chlorinated phenols and anilines.

O-Glucosyltransferase (O-GT), O-malonyltransferase (O-MAT), N-glucosyltransferase (N-GT), and N-malonyltransferase (N-MAT) activities have been detected in cultured soybean cells, using pentachlorophenol and 3,4-dichloroaniline as xenobiotic standard substrates. The O-GT was purified approximately 1000-fold, and the N-MAT approximately 70-fold. There was an extensive copurification of O-GT and O-MAT. The following functional molecular weight values were obtained, 47 kDA (O-GT), 48 kDA (O-MAT) 43 kDa (N-GT), and 48 kDa (N-MAT). O-GT and N-MAT appeared to be monomeric polypeptides with isoelectric points of approximately 4.8 and approximately 6.1, respectively. The O-GT, N-GT, and N-MAT activities had marked substrate specificities for chlorinated aromatic xenobiotics and thus illustrate the existence of plant isoenzymes with specificity for xenobiotics.

Acyltransferases↗
PubMed1991

Cross-neutralizing antibodies in rabbits immunized with HIV-1 gp160 purified from simian cells infected with a recombinant vaccinia virus.

A recombinant vaccinia virus in which the transcription of the human immunodeficiency virus type 1 (BRU isolate) env gene is driven by the 11K late vaccinia promoter yields about 10-fold higher amounts of gp160 env protein upon infection of monkey cells than does a recombinant in which gp160 is expressed using the 7.5K early-late promoter. The gp160 was purified from detergent lysates of infected cells by lentil lectin affinity chromatography followed by immunoaffinity chromatography, and was obtained in yields of 1-2 mg/10(9) cells of material estimated to be about 70% pure. Pairs of rabbits were immunized with purified gp160 using either one of five different adjuvants or an immunostimulating complex. In all cases a substantial humoral immune response was obtained after boosting, including an activity that neutralized the homologous (BRU) isolate of HIV-1. In some cases, this activity also neutralized two distantly related isolates, SF2 and MN.

Animals↗
PubMed1991

Lack of negative inotropic effects of the new calcium antagonist Ro 40-5967 in patients with stable angina pectoris.

We screened the antiischemic, hemodynamic, and inotropic effects of different dosages of the new calcium channel blocker Ro 40-5967 in 65 patients with stable effort-induced angina pectoris. In a double-blind way, patients were randomized to recieve a single oral dose of 50, 100, or 200 mg Ro 40-5967 or placebo, given as a drinking solution. Left ventricular ejection fraction (LVEF), blood pressure (BP), and heart rate (HR) were measured at rest and during a supine bicycle exercise test on day 0 (baseline) and 2 h after drug intake on day 1. Twenty-four hours later, the bicycle exercise test was repeated. Ro 40-5967 improved exercise duration and resting LVEF. After 200 mg, exercise time increased significantly from 8.4 +/- 0.8 min (mean +/- SEM) to 9.6 +/- 0.7 min (p = 0.018), and LVEF at rest increased from 54.5 +/- 2.2 to 58.1 +/- 2.6% (p = 0.045). Time to 0.1 mV ST-segment depression increased significantly from 4.3 +/- 0.8 to 5.5 +/- 0.9 min in the 100-mg group (p = 0.013) and from 4.3 +/- 1.3 to 5.4 +/- 1.5 min in the 200-mg group (p = 0.027). Maximum ST-segment depression decreased significantly at all dose levels (p = 0.01), with the maximum decrease noted in the 200-mg group (from 0.21 +/- 0.03 to 0.15 +/- 0.02 mV, p = 0.004). BP, HR, and rate-pressure product did not change significantly at rest or at maximum exercise. A single dose of Ro 40-5967 has antiischemic properties in patients with stable angina pectoris, with maximum effects obtained after 200 mg. No signs of negative inotropy were noted, and the drug was well tolerated.

Adult↗