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Biomedical subjects

D Wolf

Publications and source records attributed to D Wolf.

At least 91 records · Page 5Linked to original sources
PubMed1993

Granted publications: taken for granted?

Highly respected journals now relatively rarely publish independent research which is not grant-supported. This may lead to a reduction in the publication of innovative work.

Australia↗
PubMed1992

Effects of 5-HT4 receptor stimulation on basal and electrically evoked release of acetylcholine from guinea-pig myenteric plexus.

The effects of 5-methoxytryptamine and 5-hydroxytryptamine (5-HT) on both basal and electrically evoked outflow of tritium were studied in guinea-pig myenteric plexus preparations preincubated with [3H]-choline. Basal outflow. 5-Methoxytryptamine caused a transient and calcium-dependent increase in basal outflow of [3H]acetylcholine that was abolished by tetrodotoxin. Ondansetron (1 mumol/l) did not affect the stimulatory response of 5-methoxytryptamine but ICS 205-930 (1 and 3 mumol/l) produced parallel rightward displacements of the concentration-response curve to 5-methoxytryptamine. The pKB value for ICS 205-930 was 6.6 suggesting an involvement of 5-HT4 receptors. 5-HT caused an increase in basal outflow of [3H]acetylcholine and a biphasic concentration-response curve was obtained. The maximal response of the first phase to 5-HT (release of 0.98% of tissue tritium) and the maximal response to 5-methoxytryptamine (0.94% of tissue tritium) were similar but 5-methoxytryptamine (-log EC50: 6.9) was less potent than 5-HT (-log EC50 of the high affinity component: 7.9). ICS 205-930 (0.01-1.0 mumol/l) acted as a competitive antagonist against the low affinity component of the 5-HT concentration-response curve with a pA2 value of 8.0. It is concluded that stimulation of both 5-HT4 receptors (by 5-methoxytryptamine and submicromolar concentrations of 5-HT) and 5-HT3 receptors (by micromolar concentrations of 5-HT) causes a release of acetylcholine which in turn leads to smooth muscle contraction. Electrically evoked outflow. This outflow of [3H]-acetylcholine was concentration-dependently inhibited by both 5-methoxytryptamine and 5-HT.(ABSTRACT TRUNCATED AT 250 WORDS)

5-Methoxytryptamine↗
PubMed1992

Three types of human lung tumour cell lines can be distinguished according to surface expression of endogenous urokinase and their capacity to bind exogenous urokinase.

This study evaluates the cell surface expression of urokinase-type plasminogen activator (u-PA) and the capacity to bind exogenous urokinase as possible parameters for the distinction of various types of human lung tumours. Twelve different tumour cell lines including four small cell carcinoma, two large cell carcinoma, three squamous cell carcinoma, one adenocarcinoma and two mesothelioma cell lines of lung origin were investigated. Surface expression of endogenous u-PA was determined in a cellular radioimmunoassay (CRIA) using the u-PA-specific monoclonal antibody 98/6. To estimate additional u-PA binding capacity, exogenous two-chain, 54 kDa u-PA was employed in the CRIA. The influence of phorbol ester (PMA) treatment on expression and binding of these molecules was studied. Three different groups of lung tumour cell lines could be distinguished according to their expression of u-PA and u-PA-binding ability: (i) non small cell lung carcinoma (NSCLC) cell lines of squamous cell carcinoma/adenocarcinoma origin expressed small amounts of u-PA and bound little u-PA. Large cell carcinoma cell lines expressed high amounts of u-PA and bound large amounts of u-PA. In general, expression of u-PA and u-PA binding was enhanced after PMA treatment. (ii) Mesothelioma cell lines did not express u-PA, but were able to bind u-PA. (iii) Small cell carcinoma (SCLC) lines were devoid of surface-expressed u-PA and could not bind u-PA, both under untreated and PMA-treated conditions. It could thus be demonstrated that these three groups of lung tumour cell lines differ in their ability to express u-PA and to bind external u-PA. This may reflect the different in vivo growth behaviour and origin of the respective tumour groups.

Adenocarcinoma↗
PubMed1992

Formation of biologically active 13,14-dihydro-prostaglandin E1 during intravenous infusion of prostaglandin E1 in newborns with ductus arteriosus-dependent congenital heart disease.

Plasma concentrations of prostaglandin (PG) E1 (12-150, median 25 pg ml-1) and 13,14-dihydro-PGE1 (3-62, median 45.5 pg ml-1) were measured by gas chromatography-mass spectrometry in eight newborns with ductus arteriosus-dependent congenital heart disease during continuous intravenous infusion of PGE1. Formation of 13,14-dihydro-PGE1 was demonstrated for the first time in neonates. Since 13,14-dihydro-PGE1 has similar biological activities as the parent compound PGE1, pharmacological effects during PGE1 infusion are most likely related to both PGE1 and the generation and action of 13,14-dihydro-PGE1.

Alprostadil↗
PubMed1992

Detection of human cytomegalovirus in plasma of AIDS patients during acute visceral disease by DNA amplification.

By using the polymerase chain reaction (PCR) amplification procedure, 19 (83%) of 23 plasma specimens obtained from individuals with AIDS and human cytomegalovirus (HCMV) visceral disease were found to be positive for plasma viremia as detected by PCR (PV-PCR), whereas 78% of cultures of peripheral blood leukocytes from the same samples were found to be positive. All 11 specimens prospectively obtained from individuals with acute HCMV disease were positive by PV-PCR. Plasma specimens from patients who received ganciclovir therapy rapidly became both culture and PV-PCR negative, and there was an excellent correlation between the two procedures. DNA detected by PV-PCR was unaffected by filtering plasma through a 0.2-microns-pore-size filter, although a conserved cellular gene, HLA-DQ alpha, was undetectable by PCR following filtration. HCMV DNA in plasma could be quantitated by PV-PCR by using endpoint serial dilutions, with detectable virus being present in 10(1) to 10(-2) microliters of plasma. A low titer of infectious virus could be detected in 2 of 11 plasma samples. The detection of HCMV DNA in plasma by PV-PCR promises to be a useful procedure for monitoring patients with AIDS suspected of having impending, acute, or recurrent HCMV visceral disease and suggests an additional route by which virus may disseminate in the immunocompromised host.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Pityriasis alba in a psoriatic location.

Three patients with pityriasis alba whose lesions were confined to the knees only are reported. Such cases can be misdiagnosed as psoriasis. The key to the correct diagnosis lies in the physician's awareness of the existence of this variant of pityriasis alba.

Adult↗
PubMed1992

[Microbiological studies of self-disinfecting alginate impression materials].

Using microbiologically experimental methods and observations corresponding to praxis the efficiency of the addition of antiseptics to alginate is evaluated. The addition of chlorhexidine to the alginate leads to a considerable reduction of the amounts of germs, but an one hundred percent disinfection of the alginates is not always performed. An influence of the alginate materials and the water quality on the antimicrobial efficacy of chlorhexidine has been proved. The always occurring contamination of the impression tray rules out a complete stopping of infection between the patient and the laboratory staff.

Alginates↗
PubMed1992

[Management of patients with traveler's diarrhea].

Traveler's diarrhea starts 5 to 15 days after arrival with 3 or more watery bowel movements daily in 4 to more than 50% of travelers depending on geographical regions. Enterotoxin producing strains of E. coli are isolated in 20 to 50% of patients, followed by shigella, salmonella, campylobacter and vibrio spp. Rarely giardia lamblia, entamoeba histolytica and cryptosporidia are causative organisms. The cornerstone of treatment is oral rehydration. The efficacy of anti-diarrhetics is not convincingly proved and as to loperamid this drug may prolong invasive forms of diarrhea. Antibiotics are indicated if leucocytes or blood are found in stool. Cotrimoxazole and aminopenicillins are loosing efficacy because of growing resistance. The minimal. In a double blind placebo controlled trial with 500 mg ciprofloxacin b.i.d. for 5 days we were able to demonstrate a significant clinical and bacteriologic effect in 132 patients with salmonellosis and campylobacteriosis.

Anti-Bacterial Agents↗
PubMed1992

Nodular vasculitis associated with propylthiouracil therapy.

Cutaneous vasculitis is a rare complication of propylthiouracil therapy. We describe a patient who presented with lower extremity subcutaneous nodules, hemorrhagic bullae, and necrotic ulcers during treatment with this agent. Examination of a skin biopsy specimen revealed nodular vasculitis. This type of vasculitis has not been described in association with propylthiouracil therapy before. Nodular vasculitis not associated with the drug is characterized by a chronic protracted course, whereas in the patient reported the lesions rapidly regressed when use of the drug was discontinued.

Aged↗
PubMed1991

cDNA cloning and expression of platelet p24/CD9. Evidence for a new family of multiple membrane-spanning proteins.

This study was designed to clone, sequence, and express the full-length cDNA for the human platelet p24/CD9 antigen. A 1.3-kilobase cDNA clone was identified that has an open reading frame encoding a mature protein of 228 amino acids (approximately 25,400 Da) containing 10 cysteine residues and four putative transmembrane domains. The identity of the clone was confirmed by: (i) its predicted size, (ii) identity to four peptide sequences from the isolated protein including the NH2 terminus, and (iii) expression of the isolated clone in Xenopus oocytes and Chinese hamster ovary cells. p24/CD9 has sequence identity (24-34%) to four other cell-surface proteins: ME491, a melanoma antigen; CO-029, a carcinoma antigen; CD37, a leukocyte antigen; and SM23, an antigen of the parasitic helminth Schistosoma mansoni. The five proteins have a similar number of amino acids and are characterized by the presence of four putative transmembrane domains. These data indicate the presence of a new family of surface antigens that may function in cellular activation and differentiation.

Amino Acid Sequence↗
PubMed1991

cis Acting RNA sequences control the gag-pol translation readthrough in murine leukemia virus.

The pol gene of the Moloney murine leukemia virus (M-MuLV) is expressed as a Gag-Pol fusion protein through an in-frame suppression of the UAG termination codon located between the two genes. The role of nucleotide context in suppression was investigated, in a rabbit reticulocyte lysate translation system, using site-directed mutagenesis. The results indicate that the translational readthrough is mediated by at least 50 bases long RNA sequence located 3' to the gag UAG termination codon. Within this sequence a short purine-rich sequence adjacent to the amber codon, highly conserved among different retroviruses, appears essential for M-MuLV suppression. Two alternative putative stem and loop like RNA structures can be drawn at the gag-pol junction, one abutting the gag UAG codon, and the second downstream to it. None of these structures appears to be important to the suppression process.

Animals↗