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Biomedical subjects

U Becker

Publications and source records attributed to U Becker.

At least 145 records · Page 8Linked to original sources
PubMed1984

A functional photometric assay for plasma fibrinogen.

We have developed a photometric assay for fibrinogen concentration. The sample is mixed with a snake venom enzyme (Batroxobin) and fibrin formation is recorded turbidimetrically at 334 nm. Reaction conditions are such that a linear increase in absorbance is obtained over a concentration range of fibrinogen from 80-700 mg/dl. Higher or lower ranges can be measured by adjusting the sample volume. Calibration is performed with a single standard. Precision and accuracy are comparable with the usual clinical chemical methods. Experiments with plasma samples digested with streptokinase showed that interference of fibrinolytic split products (FSP) is less than using the Clauss method. Large amounts of FSP in the sample, however, delay the increase in absorbance. This phenomenon can be utilized for the additional estimation of the FSP-content of the sample. Results obtained with the present method corresponded well with those obtained using the method of Clauss.

Batroxobin↗
PubMed1984

Relapse prevention of duodenal ulcers with trimipramine, cimetidine, or placebo. A double-blind comparison.

In a double-blind study 83 patients with duodenal ulcers, initially healed after treatment with either 1 g cimetidine daily or 50 mg trimipramine daily, were allocated by randomization to maintenance treatment with either 400 mg cimetidine daily, 25 mg trimipramine daily, or placebo for 6 months. Monthly clinical interviews were carried out and endoscopy performed whenever the symptoms suggested ulcer relapse. After 6 months the treatment was discontinued, and the patients were observed similarly for another 6-month period. After 6 months of maintenance treatment 88% in the cimetidine group versus 55% in the trimipramine group and 53% in the placebo group remained in symptomatic remission, yielding a significant difference between the cimetidine-treated patients and the two other groups (P less than 0.05). After a further 6 months of drug-free follow-up study, the percentages were 48% versus 29% and 29% in the cimetidine, trimipramine, and placebo groups, respectively (P less than 0.05). Thus maintenance treatment with trimipramine proved no better than placebo in preventing relapses of duodenal ulcers. Second, maintenance treatment with 400 mg cimetidine daily did prevent ulcer relapse, and, third, maintenance treatment with cimetidine for 6 months did not alter the long-term course of the duodenal ulcer disease.

Adult↗
PubMed1984

Automated prothrombin-time test with use of a chromogenic peptide substrate and a centrifugal analyzer.

We modified a test for prothrombin time, to automate its performance by centrifugal analysis. The sample is activated with calcium-thromboplastin in the presence of a thrombin-specific chromogenic peptide substrate, Tos-Gly-Pro-Arg-p-nitroaniline (Chromozym TH). The endpoint of the reaction is set as the time after onset until a defined amount of substrate has been cleaved, as reflected in a fixed change in absorbance. The assay is as sensitive as clotting-type methods are to the clotting factors of the extrinsic pathway--except for fibrinogen, which can be estimated from the maximum absorbance difference. Substrate concentration has little effect on the result, and varying it does not significantly change the sensitivity to factor X, which indicates little interference with the enzymes of the coagulation cascade. The method was applied to the Cobas Bio centrifugal analyzer. An external calculator must be used to convert absorbance readings into reaction times, which can be expressed as percent-of-normal values or as "ratios" by use of reagent-specific factors. CVs were less than 2% within run, less than 6% day to day. Overall correlation with the clotting test (r = 0.95) was good. Using the Cobas Bio, we achieved a throughput rate of 200 samples per hour.

Autoanalysis↗
PubMed1983

On the pharmacokinetics of pengitoxin and its cardioactive derivative 16-acetyl-gitoxin.

The pharmacokinetics of pengitoxin has been studied in 28 healthy subjects after intravenous and oral administration. The mean plasma concentration 24 h after 0.5 mg i.v. was 5.2 ng X ml-1. Following an open two-compartment model a mean elimination half-life of 60.5 h (24.9 to 103.5 h) and a mean volume of distribution (Vdarea) of 66.91 (31.8 to 109.61) were calculated. Absorption calculated by comparison of the AUC0-infinity-values amounted to 99%. Within 4 days, 16.7% (11.7 to 21.1%) or 27.8% (18.4 to 33.7%) (0.5 mg i.v. or 1.2 mg p.o.) was excreted in urine. After pengitoxin 0.5 mg i.v. total body clearance and renal clearance were 13.3 ml X min-1 (7.0 to 18.6 ml X min-1) and 3.0 ml X min-1 (1.9 to 3.9 ml X min-1) respectively. The elimination half-life of pengitoxin is longer than that of digoxin and distinctly shorter than that of digitoxin, whilst its distribution volume and clearance are closer to those of digitoxin than of digoxin.

Acetyldigoxins↗
PubMed1983

Efficacy of trimipramine and cimetidine in the treatment of duodenal ulcer. A double-blind comparison.

One hundred and fourteen consecutive outpatients with endoscopically proven duodenal ulcers were allocated in a double-blind study to treatment with either trimipramine (Surmontil), 50 mg at bedtime, or cimetidine (Tagamet), 200 + 200 + 200 + 400 mg/day, using identical-appearing active and placebo tablets to fill in the treatment scheme. One hundred and eight patients completed the study. Ulcer healing was assessed by endoscopy at 3, 6, and 9 weeks. Clinical symptoms and antacid consumption were recorded by means of interviews and a diary card system. The cumulated healing rate with cimetidine and trimipramine, respectively, was at 3 weeks 64% versus 40% (p less than 0.05), at 6 weeks 89% versus 65% (p less than 0.05), and 9 weeks 91% versus 78% (n.s.). We found no significant differences between the two groups with regard to pain relief, antacid consumption, or general symptomatic improvement.

Adolescent↗
PubMed1982

Persistent protoporphyrinemia in hereditary porphobilinogen synthase (delta-aminolevulinic acid dehydrase) deficiency under low lead exposure. A new molecular basis for the pathogenesis of lead intoxication.

For several years, a 4-12-fold increase of the upper normal limit in erythrocyte protoporphyrin concentrations persisted in two men 34 and 39 years of age who were chronically exposed to lead. We are dealing with a zinc protoporphyrinemia in both cases, without lead intoxication or anemia. The 34-year-old had been a regular blood donor for 10 years and had already been treated for iron deficiency several times. Hemoglobin, red cell counts, hematocrit, and iron were at the lower normal limit. The activity of porphobilinogen synthase (PBG-S), uroporphyrinogen-synthase and -decarboxylase as well as urinary porphyrin precursors and porphyrin excretion were normal. Protoporphyrinemia was said to be due to a prelatent/latent iron deficiency. In the 39-year-old, the activity of PBG-S was lowered to 388 mumol/1 . h, as compared to the mean of controls (1,190 +/- 210, x +/- SD, n = 50), in connection with a slightly elevated excretion of delta-aminolevulinic acid and coproporphyrin in the urine and a high-normal blood lead level. In his family there was no history of either a protoporphyrinemia or a hematological disturbance. Six of eight family members in three generations showed a diminished activity of PBG-S: 600 +/- 160, P less than 0.001 compared to controls. These family members are heterozygous with regard to the PBG-S deficiency; they are clinically unobtrusive in comparison to homozygotes with an acute prophyria syndrome. Activation by zinc and reactivation by dithiothreitol were normal in contrast to PBG-S from patients with lead intoxication. The cause of biochemical symptoms of subclinical lead intoxication developed by the propositus is probably due to the hereditary PBG-S deficiency which sensitizes him to low-level lead exposure. The determination of red cell PBG-S activity can be recommended as a test detecting heterozygotes. The hereditary PBG-S deficiency is recognized as a new molecular basis for the pathogenesis of lead intoxication.

Adult↗
PubMed1982

Semi-automatic detection of gunshot residue (GSR) by scanning electron microscopy and energy dispersive X-ray analysis (SEM/EDX).

Wide strips of adhesive tape (40 mm x 86 mm) are pressed for about one minute on the thumb, forefinger and outer edge of a subject's hand. Subsequently these tapes are fixed to a cylinder that rotates within the SEM chamber and is adjustable in an axial direction. The tapes are scanned for possible GSR particles with simultaneous SE and X-ray imaging. The X-ray signal caused by particles of high atomic number automatically stops the rotating cylinder, and the EDX spectrum of the suspect particle is produced within five seconds. A chart is then plotted to record the size, elemental composition, morphology and tape coordinates of the particles of interest. The outcome is a complete map of GSR particles found on certain parts of the hand, and this map has a characteristic pattern depending on the firearm used, the ammunition and the circumstances of the shooting incident. The time lapse between firing and sampling may allow this GSR pattern to change, but this method is helpful in suicide/homicide decisions.

Fingers↗
PubMed1979

A new method for the determination of gastrointestinal transit times.

A new method for the determination of the gastrointestinal transit time (TT) is described. The normal range of the TT was 40--95 h in 58 normal subjects. No age or sex variation of the TT was disclosed. In 25 out-patients with the irritable bowel syndrome the TT was determined before and after 3 weeks' treatment with Vi-Siblin. Of these patients, 20% initially showed a prolonged TT; this decreased during treatment with Vi-Siblin. In the patients with normal TT, this remained unchanged during the treatment. Our study suggests that patients with long TT, long intervals between bowel movements, and frequent attacks of colicky abdominal pain may derive benefit from a plant fibre supplement to their diet. The method for the determination of the TT described is well suited to out-patient studies--also in large populations--since it is relatively easy to perform, stool collection is unnecessary, and the method shows good reproducibility.

Adult↗