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Biomedical subjects

H Matthes

Publications and source records attributed to H Matthes.

At least 55 records · Page 3Linked to original sources
PubMed1989

Cloning of the gene encoding the yeast protein BTF1Y, which can substitute for the human TATA box-binding factor.

An activity (designated BTF1Y) in extracts of Saccharomyces cerevisiae can substitute for the human TATA box-binding factor BTF1 in a reconstituted transcription system containing the adenovirus 2 major late promoter, RNA polymerase B (II), and the basic transcription factors BTF2, BTF3, and STF. We have purified BTF1Y to homogeneity, using as assays reconstitution of in vitro transcription and DNase I footprinting on the TATA element. Both activities copurified with a 27-kDa polypeptide as determined by SDS/PAGE. Gel filtration indicated a molecular mass of 28 +/- 5 kDa under nondenaturing conditions, suggesting that the native BTF1Y protein is a monomer. BTF1Y was enzymatically cleaved, several peptides were sequenced, and appropriate oligonucleotide probes were synthesized to clone the BTF1Y gene from a yeast genomic library. The BTF1Y gene contains a 720-base-pair open reading frame encoding a protein of 27,003 Da. The recombinant protein expressed in HeLa cells exhibited the same chromatographic characteristics and in vitro transcriptional activity as BTF1Y prepared from yeast extracts, confirming the identity of the gene. Gene-disruption experiments indicated that the yeast BTF1Y gene is a single-copy essential gene.

Adenoviruses, Human↗
PubMed1989

Pharmacokinetics of the antidepressant rolipram in healthy volunteers.

1. The pharmacokinetics of rolipram were studied in healthy male volunteers using 3H-rolipram and a radioimmunoassay for measurement of unchanged drug. 2. Rolipram was rapidly and completely absorbed after an oral dose of 1 mg. Bioavailability was 73%. 3. Plasma levels of the unchanged drug declined with a terminal half-life of 2 h. The total clearance of rolipram was 2 ml/min per kg. 4. Labelled rolipram was excreted rapidly and completely. The main route of elimination was via the urine.

Administration, Oral↗
PubMed1988

Establishment of human Ig producing heterohybridomas by fusion of mouse myeloma cells with human lymphocytes derived from peripheral blood, bone marrow, spleen, lymph node, and synovial fluid. Effect of polyclonal prestimulation and cryopreservation.

50 fusion experiments were carried out to analyse heterohybridization efficiencies on mouse myeloma cells of the P3 X63 Ag8/653 line with human lymphocytes derived from peripheral blood, bone marrow, lymph node, spleen or synovial fluid. We found higher yields of growing and human Ig-producing hybridoma lines when lymphocytes from spleen or lymph node were fused. Although primary hybridomas could be established from fusions with bone marrow-derived cells, only in nine out of 1616 initially seeded wells was Ig production registered. Four fusions using immune cells from synovial fluid were made without success. Independently of the source of lymphocytes pokeweed mitogen (PWM) prestimulation had no enhancing effect on the percentage of wells with cell growth and this did not alter the IgM:IgG ratio in primary hybridomas (9:1), although cells from all compartments used here (with the exception of bone marrow cells) could be stimulated with PWM to produce both IgG and IgM in cultures. Cryopreserved lymphocytes from different sources could be used for fusions with comparable results registered for the fresh material.

Animals↗
PubMed1988

Fluocortolone: pharmacokinetics and effect on ACTH and cortisol secretion during daily and alternate-day administration.

The pharmacokinetics of fluocortolone and its effect on the circadian rhythm of plasma cortisol and ACTH have been studied during different schedules of oral administration. Groups of 6 healthy male adults were given a single daily dose of fluocortolone 5, 10 and 20 mg, and another group received 20 mg every second day. Administration to all groups was continued for 8 days. Pharmacokinetic parameters of fluocortolone (half lives of absorption-t1/2a and elimination t1/2e, volume of distribution V and oral clearance (CL/f) were independent of the duration of treatment and dose. Areas under the plasma level curves, AUC and Cmax values increased in proportion to the dose, indicating dose linearity of fluocortolone pharmacokinetics. A normal morning cortisol peak occurred during all treatment schedules, which indicates that circadian cortisol secretion was not seriously affected by the glucocorticoid treatment. On the other hand, when the level of circulating fluocortolone was high the 12.00 a.m. and 4.00 p.m. cortisol levels were diminished compared to the pre and posttreatment values. There was no definite correlation between the ACTH and cortisol levels, either on treatment or on control days. ACTH levels were suppressed by daily treatment with the 20 mg dose. Thus, even during administration of a high dose of a glucocorticoid, the circadian secretion of cortisol can be preserved if the treatment is adjusted according to the half-life of the drug.

Administration, Oral↗
PubMed1986

Multiple sequence motifs are involved in SV40 enhancer function.

A systematic mutagenesis of the SV40 enhancer indicates that it spans approximately 100 bp and is composed of at least two distinct DNA domains which exhibit very little enhancing activity on their own. Their association results in a 400-fold enhancement of transcription, virtually irrespective of their relative orientation and, to some extent, of the distance between them. Enhancer activity can also be generated by duplication of either domain. We show also that the activity of each domain is due to the presence of several specific sequence motifs. These motifs are found assorted in different combinations in other viral and cellular enhancers.

Base Composition↗
PubMed1986

Fluocortolone: pharmacokinetics and effect on plasma cortisol level.

The pharmacokinetics of fluocortolone and its effect on plasma cortisol levels are described after oral administration of 20, 50 and 100 mg to 9 healthy adults. The concentrations of fluocortolone and cortisol in plasma were measured simultaneously by HPLC with UV detection. Fluocortolone was rapidly absorbed after all doses, giving the maximum plasma level after 1.4-2.1 h. After ingestion of 20, 50 and 100 mg, the peak levels were 199, 419 and 812 ng/ml, respectively. The maximum plasma levels and areas under the plasma level-time curves increased in proportion to the dose. Post-maximum plasma levels declined monoexponentially with a half-life of 1.76 h. Plasma half-life (t1/2 = 1.76 h), volume of distribution (1.03 l/kg) and oral clearance (6.9 ml/min/kg) were independent of the dose. The intensity and duration of adrenal suppression was dose dependent. Maximum suppression was observed 8 hours after fluocortolone. Clearcut suppression of cortisol levels after 24 hours was only seen following 100 mg fluocortolone.

Adult↗
PubMed1986

Specific protein binding to the simian virus 40 enhancer in vitro.

HeLa cell nuclear extracts and wild-type or mutated simian virus 40 enhancer DNA were used in DNase I footprinting experiments to study the interaction of putative trans-acting factors with the multiple enhancer motifs. We show that these nuclear extracts contain proteins that bind to these motifs. Because point mutations which are detrimental to the activity of a particular enhancer motif in vivo specifically prevent protection of that motif against DNase I digestion in vivo, we suggest that the bound proteins correspond to trans-acting factors involved in enhancement of transcription. Using mutants in which the two domains A and B of the simian virus 40 enhancer are either separated by insertion of DNA fragments or inverted with respect to their natural orientation, we also demonstrate that the trans-acting factors bind independently to the two domains.

Base Sequence↗
PubMed1986

Electrical properties of sodium bicarbonate symport in kidney epithelial cells (BSC-1).

Intracellular potentials of BSC-1 kidney epithelial cells known to express a Na+-HCO3- symport ranged between -40 and -70 mV, mean value Vm = -55.1 +/- 10.1 mV. Lowering HCO3- at constant partial pressure of CO2 (PCO2) or complete removal of HCO3-/CO2, rapidly depolarized, whereas readding HCO3- hyperpolarized Vm (40 +/- 8 mV/decade HCO3- at constant PCO2). This response was largely reduced by 1 mM 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) (which depolarized Vm to about -20 mV) and in Na+-free medium, but Ba2+ had no effect. In HCO3(-)-Ringer, Na+ removal rapidly depolarized Vm (by 32 +/- 7 mV), and readdition hyperpolarized Vm. This was reduced in HCO3(-)-free medium or by 1 mM DIDS, but not by amiloride (10(-5) and 10(-3) M) or ouabain (10(-4) M). In the absence of HCO3- and/or Na+, steady-state Vm was reduced to -12 +/- 5 mV. Cl- removal had no effect on the responses to Na+ and/or HCO3- and led to a slow steady-state depolarization. Both in the presence and absence of HCO3-, raising pHi (changed by NH4Cl or butyrate) depolarized, whereas lowering pHi hyperpolarized Vm. Lowering pHo in HCO3(-)-free Ringer depolarized Vm (23 +/- 4 mV/decade H+). The slope conductance for K+ is only 6 +/- 2 mV/decade. Thus BSC-1 cells display typical electrical characteristics of Na+-HCO3- symport. In contrast to other systems, the data are compatible with a net electrogenic inward transport of Na+ and HCO3-. There might be an additional H+-(OH-) conductance operating also under nominally bicarbonate-free conditions.

Amiloride↗
PubMed1985

Kidney epithelial cells of monkey origin (BSC-1) express a sodium bicarbonate cotransport. Characterization by 22Na+ flux measurements.

Na movement across the plasma membranes of confluent monolayers of monkey kidney epithelial cells (BSC-1) was studied using 22Na+ uptake and efflux techniques in the presence of 10(-4) M ouabain. In the presence of 28 mM bicarbonate, uptake was inhibited by both 10(-3) M amiloride and 10(-3) M 4,4'diisothiocyanostilbene-2,2'-disulfonic acid (DIDS). In DIDS-pretreated cells, 10(-3) M amiloride led to a further reduction of 22Na+ uptake, while 10(-5) furosemide was ineffective. DIDS also inhibited sodium efflux, indicating that the DIDS-sensitive pathway mediates both influx and efflux of 22Na+. DIDS-sensitive 22Na+ uptake, as studied in the presence of both 10(-4) M ouabain and 10(-3) M amiloride, was abolished by the absence of bicarbonate, which could not be substituted by other plasma membrane-permeable buffers. In 28 mM HCO3-, DIDS-sensitive uptake of 28 mM Na+ was cis-inhibited by 124 mM Na+, but no significant inhibition by K+ or Li+ was found. DIDS-sensitive 22Na+ uptake was a saturable function of both Na+ concentration (apparent Km between 20 and 40 mM at 28 mM HCO3-) and HCO3- concentration (apparent Km between 7 and 14 mM at 151 mM Na+). Intracellular microelectrode measurements showed that net Na+ transport in the presence of HCO3- is electrogenic, i.e. that there is anion cotransport with Na+. This effect is abolished by 1 mM DIDS. It is concluded that monkey kidney epithelial cells possess a stilbene-sensitive, electrogenic sodium bicarbonate symport, which may play an important role in bicarbonate reabsorption in the mammalian kidney.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1985

Anion dependence of electrical effects of bicarbonate and sodium on cultured bovine corneal endothelial cells.

Using intracellular microelectrode technique, the effect of anion substitution on the voltage responses to extracellular bicarbonate and sodium was explored in cultured bovine corneal endothelial cells. The overall amplitude of voltage changes induced by periodic changes of [HCO-3]o (depolarization upon removal of HCO-3 and hyperpolarization upon readdition) was reduced when Cl- was replaced by organic anions (cyclamate, methylsulfate, benzenesulfonate) or by SO4(2-), and to a lesser extent by substitution with Br-. There was a similar effect of anion substitution on the response to changes of [Na+]o. In both cases, in the absence of Cl, the voltage V returned at a slower rate to baseline levels after it had been transiently changed by either an imposed Na- or HCO3- gradient, indicating a slower dissipation of these gradients. The direct response of V to these imposed gradients was affected only to a minor degree. Replacement of Cl- by SO4(2-) or organic anions led to a slow, reversible depolarization of the cell, while substitution with Br- had only a slight effect. The effect of anion substitution on the voltage responses to HCO-3 or Na+ could not be mimicked by a depolarization induced by Ba2+ (1 mM). Furosemide (10(-3) M) led to a slight reduction of the voltage responses to HCO-3, but could not suppress the effect of anion substitution on these reactions. It could neither suppress the depolarization induced by anion substitution and had no effect on steady-state PD. It is suggested, that cultured bovine corneal endothelial cells, in addition to a previously demonstrated electrogenic HCO-3-Na+-cotransport, which is probably not dependent on Cl, possess an electroneutral mechanism for HCO-3 and/or Na+-movement, which depends on Cl. No evidence for a Cl-conductance could be obtained.

Animals↗
PubMed1985

A molecular basis for the Ia.2 and Ia.19 antigenic determinants.

The murine Ia antigens, heterodimeric glycoproteins on the surface of immunocompetent cells, restrict immune recognition by their influence on cell-cell interactions. Many serological specificities have been mapped to these molecules, and monoclonal antibodies directed against some of these determinants block antigen presentation to T lymphocytes. As a step toward a better understanding of Ia function, we sought to define the molecular basis of Ia.2 and Ia.19, specificities found on the A alpha chain of only the k or of both k and r haplotypes, respectively. We report nucleotide sequences for the A alpha chain cDNAs of the k, r, and s haplotypes, which, when compared to previously published A alpha sequences, demonstrate the existence of one k-specific amino acid residue and of another present only in the k and r haplotypes. These residues must thus play an important role in the generation of Ia.2 and Ia.19 specificities.

Alleles↗
PubMed1983

Transcription from the SV40 early-early and late-early overlapping promoters in the absence of DNA replication.

Transcription for a hybrid SV40 promoter-beta globin coding sequence recombinant initiates from both early-early (EE) and late-early (LE) SV40 start sites (EES and LES) in the absence of DNA replication. The 72-bp repeat is essential to potentiate the elements of the two overlapping EE and LE promoters (EEP and LEP). Two current models, which can account for the EE to LE shift in RNA chain initiation during the SV40 replication cycle, are that LE transcription is linked to replication and occurs on newly replicated DNA molecules or that there are two promoter elements, a stronger EEP and a weaker LEP, T antigen repressing the EEP late in infection. Our results support the second model. A 5'-TATTTAT-3' to 5'-TATCGAT-3' mutation in the putative SV40 TATA box decreases transcription from EES, increases transcription from LES, and inhibits DNA replication. Therefore, this element acts as a classical TATA box for transcription, and yet is also important for DNA replication.

Animals↗
PubMed1982

The protective action of fluocortin butylester (FCB) in the nasal antigen provocation test: a controlled double-blind, crossover study.

Fluocortin butylester (FCB), a locally active corticosteroid, was inhaled as a fine powder mixed with lactose using the rhinolator in a comparative double-blind, crossover study against placebo. Fifty patients of both sexes and aged from 16 to 46 years with an established seasonal allergic rhinitis, but free of symptoms, took part in this trial. The determination of the protective action after allergen provocation was performed after seven days treatment with 4 mg FCB or placebo. Measurements of the nasal resistance and the temperature were taken after provocation. The symptoms of nose and eyes were recorded. The protective effect of FCB against nasal provocation with grass pollen extracts was statistically proved.

Adolescent↗