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Biomedical subjects

R Kaufmann

Publications and source records attributed to R Kaufmann.

At least 271 records · Page 15Linked to original sources
PubMed1984

[Leg ulcers in essential thrombocythemia].

By means of two case reports, essential thrombocythemia is discussed as an uncommon cause of leg ulcers, and the other possible cutaneous manifestations of this disease are briefly outlined.

Aged↗
PubMed1983

[Hair transplantation: gelatin plugs for hemostasis].

Uncontrolled bleeding at the recipient site is a complicating factor in hair transplant surgery. As a consequence, time consuming procedures as well as further discomfort for the patient is inevitable. In order to achieve adequate hemostasis, we present an easy method using cylindrical gelatin-plugs.

Gelatin↗
PubMed1983

Hepatitis B vaccine: safety study in anti-HBs seropositive human volunteers.

HBsAg, which has been purified from HBsAg and HBeAg positive plasma, was repeatedly applied to human volunteers, who were seropositive for anti-HBs. The intramuscular or subcutaneous injections caused a clear booster effect on anti-HBs concentrations in serum. The injections were well tolerated. Only minor local side effects occurred. Vaccination left serum transaminase activities unaffected. None of the volunteers developed serologic or clinical signs related to viral hepatitis.

Adult↗
PubMed1983

Hepatitis B vaccine: safety study in anti-HBs seronegative human volunteers.

A hepatitis B vaccine which has been prepared from HBsAg and HBeAg positive human plasma and which consists of purified HBsAg in an alum suspension was investigated for safety and immunogenicity in a clinical trial. Twenty-three anti-HBs seronegative volunteers received three injections each of 40 micrograms HBsAg intramuscularly. No rise in serum transaminase activities occurred during the follow-up period, and none of the volunteers developed clinical signs related to viral hepatitis. Only minor side reactions like burning or reddening at the site of injection were reported by the volunteers. 100% seroconversion occurred within 150 days after first vaccination. The subsequent two vaccinations caused a strong booster effect.

Adult↗
PubMed1983

[5-Fluorouracil therapy following curettage of warts].

Of our patients recorded so far 31% showed local recurrences after topical 5-fluorouracil treatment following curettage of warts. Based on our provisional results we do not consider this technique acceptable for further use.

Fluorouracil↗
PubMed1982

Calcium uptake into acini from rat pancreas: evidence for intracellular ATP-dependent calcium sequestration.

Intracellular ATP-dependent Ca2+-sequestration mechanisms were studied in isolated dispersed rat pancreatic acini following treatment with saponin or digitonin to disrupt their plasma membranes. In the presence of 45Ca2+ concentrations less than 10(-6) mol/liter, addition of 5 mmol/liter ATP caused a rapid increase in 45Ca2+ uptake exceeding the control by fivefold. ADP mimicked the ATP effect by 50 to 60%, whereas other nucleotides such as AMP-PNP, AMP-PCP, CTP, UTP, ITP, GTP, cAMP and cGMP did not. Maximal ATP-promoted Ca2+ uptake was obtained at 10(-5) mol/liter Ca2+. Inhibition of Ca2+ uptake by mitochondrial inhibitors was dependent on the Ca2+ concentration, indicating the presence of different Ca2+ storage systems. Whereas the apparent half-saturation constant found for mitochondrial Ca2+ uptake was approximately 4.5 X 10(-7) mol/liter, in the presence of antimycin and oligomycin (nonmitochondrial uptake) it was approximately 1.4 X 10(-8) mol/liter. In the absence of Mg2+ both ATP- and ADP-promoted Ca2+ uptake was nearly abolished. The Ca2+ ionophore and mersalyl blocked Ca2+ uptake, Electron microscopy showed electron-dense precipitates in the rough endoplasmic reticulum of saponin-treated cells in the presence of Ca2+, oxalate and ATP, which were absent in intact cells and in saponin-cells without ATP or pretreated with A23187. The data suggest the presence of mitochondrial and nonmitochondrial ATP-dependent C2+ storage systems in pancreatic acini. The latter is likely to be located in the rough endoplasmic reticulum.

Adenosine Diphosphate↗
PubMed1982

The effect of change in a stimulus sequence on P300.

In past studies, the P300 amplitude of the ERP has been found to be enhanced for infrequent, unpredictable and/or task-relevant eliciting events. A fourth factor, namely the physical change between two consecutive stimuli in event sequences used, has often been confounded with frequency, predictability and relevance. The current study examined whether change also increases the P300 amplitude. Fourteen adults viewed sequences of slides in which predictability, task (counting) and change varied within subject. ERP was recorded at Cz, Pz, Oz and Fz. P300 amplitudes were significantly larger: (1) for unpredictable than for predictable events, (2) for counted than for non-counted stimuli, and (3) for stimulus change rather than no stimulus change. The change effect interacting with counting suggested that P300 amplitude may be particularly increased by stimulus changes imbedded within only certain cognitive tasks.

Adult↗
PubMed1982

The laser microprobe mass analysis technique in the studies of the inner ear.

Laser microprobe mass analysis (LAMMA) has been used to investigate cation and anion concentration in shock frozen, freeze-dried and plastic embedded inner ear tissue. Dissected inner ear specimens were prepared in various media of known ionic compositions and the influence on the K/Na ratio was measured in the lateral cochlea wall (spiral ligament, stria vascularis). For control purposes of the various procedures employed, muscle specimens (external standard) were processed in parallel. It was found that there is a good correlation between the K/Na ratio and the preservation of the tissue fine structure by comparing the results in tissues with different degrees of freezing damage.

Cochlea↗
PubMed1982

Detection of aluminum by LAMMA spectrometry in plasma and in synovial liquids of patients on chronic dialysis.

The LAMMA (Laser Microprobe Mass Analysis) provides a semi quantitative analysis of mineral and organic ions. This microprobe has been applied in determining the aluminum detection threshold in sera or in synovial fluid of patients on chronic dialysis whose treatment includes some aluminum compounds. The limit of aluminum detection in a lyophilised sera is about 4 ppm that allows to expect on equivalent threshold in biological in heterogous matrices.

Aluminum↗
PubMed1982

[Human pharmacokinetics of different i.v. doses of azapropazone (HPLC-determination) (author's transl)].

The pharmacokinetic profile of azapropazone (Prolixan), sodium salt of 5-dimethylamino-9,5-dimethylamine-9-methyl-5-propyl-1H-pyrazolol[1,2-a][1,2,4]benzotriazine-1,3(2H)-dione, was established. Six healthy, adult volunteers received a single dose of either 600 mg or 1200 mg azapropazone as sodium salt intravenously. The drug was selectively separated from its metabolites and other plasmatic compounds and it was quantified by measurement of extinction at 254 nm. The kinetic parameters of azapropazone were independent of the applied dose (600 mg and 1200 mg): Biological half-life (t0.5): 16.8 +/- 2.95 h and 17.2 +/- 3.0 h; Total clearance (Cltot): 10.2 +/- 2.1 ml min-1 (both doses); Central volume of distribution (Vc): 3.7 +/- 0.71 and 3.9 +/- 0.91; Apparent volume of distribution (Vd): 12.5 +/- 2.91 and 14.4 +/- 2.41. Initial serum concentrations were 170 +/- 41.5 micrograms ml-1 and 326.3 +/- 84.5 micrograms ml-1, determined by extrapolation (C0 at time t0). The areas under the plasma concentration curves (AUC0 infinity) were calculated to amount 1052.5 +/- 217.4 micrograms ml-1h-1 and 2078.4 +/- 515.9 micrograms ml-1h-1. Three rate constants associated with the elimination of the drug could be calculated.

Adult↗
PubMed1981

Drug-induced zeta potential changes in liposomes studied by laser Doppler spectroscopy.

The technique of laser Doppler spectroscopy is used to measure the electrophoretic mobility of liposomes under the influence of one beta-blocking agent and three local anesthetics. All four drugs decrease the mobility (i.e., the zeta potential) of negatively charged phospholipids (soybean lipids, phosphatidylserine and cardiolipin). The mobility of electrostatically neutral pure phosphatidylcholine (zero mobility under control conditions at pH 7 and 4) is increased linearly with the logarithm of drug concentration, indicating binding and incorporation of positively charged drug molecules. The sequence of strength of activity, measured by zeta-potential changes, corresponds to that found in biological tissues: propranolol greater than tetracaine greater than lidocaine greater than procaine. For purely negatively charged lipids (phosphatidylserine, cardiolipin) the activity of the drug is higher at acidic pH, (pH 4), while for electrostatically neutral (phosphatidylcholine) or partly neutral (soybean) lipid liposomes drug activity is about the same at pH 9, 7 and 4. A Hill plot of the data reveals noncooperative drug binding. From the line width of the scattering power spectrum the mean particle radius and the average interparticle distance in the samples are determined.

Adrenergic beta-Antagonists↗
PubMed1981

Electrokinetic properties of (Na+, K+)-ATPase vesicles as studied by laser Doppler spectroscopy.

The technique of laser Doppler electrophoresis was applied for the study of the surface charge properties of (NA+, K+)-ATPase containing microsomal vesicles derived from guinea-pig kidney. The influence of pH, the screening and binding of uni- and divalent cations and the binding of ATP show: (1) one net negative charge per protein unit with a pK = 3.9; (2) deviation from the Debye relation between surface potential and ionic strength for univalent cations, with no difference in the effect of Na+ and K+; (3) Mg2+ binds with an association constant of Ka = 1.1. 10(2) M-1 while ATP binds with an apparent Ka = 1.1.10(4) M-1 for 1 mM NaCl, 0.2 mM KCI, 0.1 mM MgCl2, 0.1 mM Tris-HCl2, 0.1 mM Tris-HCl (pH 7.3). The binding is weaker at higher Mg2+ concentrations. There is no ATP binding in the absence of Mg2+. In addition, the average vesicle size derived from the linewidth of the quasielastic light scattering spectrum is 203.7 +/- 15.2 nm. In the presence of ATP a reduction in size is observed.

Animals↗
PubMed1981

Cell electrophoresis for diagnostic purposes. I. Diagnostic value of the electrophoretic mobility test (EMT) for the detection of gynaecological malignancies.

Lymphocytes from 278 gynaecological patients (100 controls and 178 patients with a malignant condition) have been investigated for their response to encephalitogenic factor, cancer basic protein, and KCl extract of adenocarcinoma of the body of the uterus as "antigens", using tanned sheep erythrocytes ETS as indicator particles in the electrophoretic mobility test (EMT). Electrophoretic mobility was measured with a Zeiss cytopherometer. The study was split into three test series producing in the cancer group 66% correct positive test results (34% false negatives) and in the control group 83% correct negative results (17% false positives). Consequently, with the instrumentation used, EMT is, at least in our hands, not sufficiently reliable for the diagnosis of cancer.

Adenocarcinoma↗