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Biomedical subjects

R Richter

Publications and source records attributed to R Richter.

At least 109 records · Page 6Linked to original sources
PubMed1990

Cervicovaginal microflora and pregnancy outcome: results of a double-blind, placebo-controlled trial of erythromycin treatment.

Available information suggests that some instances of preterm birth or premature rupture of membranes are associated with clinically unrecognized infection and inflammation of the lower uterine segment, decidua, and fetal membranes. Various cervicovaginal microorganisms have been recovered from these sites. Many of these microorganisms produce factors that may lead to weakening of the fetal membranes, release of prostaglandins, or both. This study evaluated the presence of various lower genital tract microflora and bacterial conditions in 229 women enrolled in a double-blind, placebo-controlled trial of short-course erythromycin treatment at 26 to 30 weeks' gestation to prevent preterm birth. Demographic, obstetric, and microbiologic parameters were prospectively evaluated. Premature rupture of membranes occurred less frequently (p less than 0.01) among women who received erythromycin (6%) versus placebo (16%). Preterm premature rupture of membranes also occurred less frequently, although not significantly (p = 0.3) in patients who received erythromycin (2%) versus placebo (5%). Erythromycin treatment significantly decreased the occurrence of premature rupture of membranes among women who were initially positive for Chlamydia trachomatis infection. Logistic regression analysis demonstrated that C. trachomatis (p = 0.05; odds ratio, 9), vaginal wash phospholipase C (p = 0.08; odds ratio, 6) and prior preterm birth (p = 0.007; odds ratio 17) were associated with increased risk of preterm birth. Bacterial vaginosis, Mycoplasma hominis, Ureaplasma urealyticum were not significantly associated with increased risk of preterm birth or preterm rupture of membranes. These findings support a role for selected lower genital tract microflora in preterm birth and premature rupture. Large controlled treatment trials of specific infections or conditions associated with preterm birth and premature rupture of membranes are required to confirm the value of antimicrobial treatments in prevention of microbial-associated preterm birth.

Adolescent↗
PubMed1990

Induction of levansucrase in Bacillus subtilis: an antitermination mechanism negatively controlled by the phosphotransferase system.

The target of the induction by sucrose of the levansucrase gene is a transcription terminator (sacRt) located upstream from the coding sequence, sacB. The two-gene locus sacX-sacY (formerly sacS) and the ptsI gene were previously shown to be involved in this induction. ptsI encodes enzyme I of the phosphoenolpyruvate-dependent phosphotransferase system. SacX is strongly homologous to sucrose-specific phosphotransferase system-dependent permeases. SacY is a positive regulator of sacB. Here we show that SacY is probably an antiterminator interacting directly with sacRt, since in Escherichia coli the presence of the sacY gene stimulates the expression of a reporter gene fused downstream from sacRt. Missense mutations affecting sacY were sequenced, and the sacB regulation was studied in isogenic strains carrying these mutations or in vitro-generated mutations affecting sacX, sacY, or ptsI. The phenotype of double mutants suggests a model in which SacX might be a sucrose sensor that would be phosphorylated by the phosphotransferase system and, in this state, could inhibit the SacY antiterminator. Exogenous sucrose, or a mutation inactivating the phosphotransferase system, would dephosphorylate SacX and allow antitermination at sacRt.

Bacillus subtilis↗
PubMed1990

[Conservative, non-hormonal treatment of benign prostatic hyperplasia].

The indications for and efficacy of non-hormonal drugs in the treatment of benign prostatic hyperplasia (BPH) are the subject of some controversy. However, a critical evaluation of the available literature shows that no clinically relevant reduction of prostatic size has been reached with any drug tested so far. It is suggested that alpha-adrenergic blockers exert a beneficial effect by reducing the "dynamic" component associated with prostatic obstruction. The application of objective criteria has not shown cholesterol-lowering and phytotherapeutic drugs to have any significant and clinically relevant advantage over placebos. The evaluation of drug therapy in BPH patients is complicated by the fact that the obstructive signs are masked by irritative symptoms ("prostatism", "unstable bladder"), the causes of which are also unknown. A causal drug therapy should have an impact on biochemically and/or biologically confirmed changes that are responsible for the development of BPH. Als long as the cause of BPH remains unknown, drugs cannot fulfil these requirements. The efficacy of drug therapy in patients with BPH can only, therefore, be evaluated in double blind controlled studies including modern urodynamic investigations. However, these standards should also be applied to the decision as to whether operative treatment is indicated and to evaluation of the results.

Adrenergic alpha-Antagonists↗
PubMed1990

[Echocardiography studies for detection of cardiotoxic side effects of anthracycline therapy in childhood].

An anthracycline-induced cardiomyopathy can already appear at a total cumulative dose of less then 550 mg/m2. Noninvasive cardiological methods have been used in order to detect these fatal side effects early. For cardiological control we applied echo-cardiography with measurements of ventricular size and left ventricular function. 5 out of 39 children who were off anthracycline therapy for 3 months to 8 years showed a decline in left ventricular function, but no clinical symptoms. At present 16 children with anthracycline therapy are controlled by echocardiography. In 2 patients a transient myocardial dysfunction was diagnosed. After stopping anthracycline therapy the left ventricular function improved within 2 to 3 months without specific cardiac treatment.

Adolescent↗
PubMed1990

[Psychophysiologic microperspective in the psychotherapy process--a sequential approach of investigation].

To Investigate the interpersonal psychophysiology in the psychotherapeutic process a sequential approach using single case analysis is presented. During 18 psychoanalytic-psychosomatic initial interviews simultaneous recordings of heart periods (IBI) and arrhythmia scores (from ecg) and the psychotherapeutic dialogue were made from 10 patients with cardiac neurosis and their interviewers. The general finding is that therapists were able to forecast those segments better, in which their own physiological activity was involved than the segments of their patients. Consideration is given to the consequences which should be drawn from these results for psychophysiological psychotherapy research.

Adult↗
PubMed1990

Comparative measurements of membrane potentials in chromaffin cells from spontaneously hypertensive and from normotensive WKY rats.

Comparative measurements of the membrane potential (MP) of chromaffin cells (CC) were made in tissue slices of adrenals from spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) controls. We found for SHR a mean MP of -30.2 +/- 0.71 mV and for WKY a mean value of -33.0 +/- 0.80 mV. There was no significant difference between the mean MPs of the left and right adrenals of both rat strains. In the presence of 5.10(-5) M acetylcholine the mean MP significantly fell by 6.3 mV (SHR) and 9.7 mV (WKY), respectively. The present results indicate that different enzyme activities and processes of catecholamine storage in adrenals of SHR and WKY are obviously not correlated with changes in the MP of CC.

Acetylcholine↗
PubMed1990

[Research activity in the psychosomatic medicine/psychotherapy specialty at West German universities--a 1978-1988 status report].

The documentation of research activities in the discipline of psychosomatics/psychotherapy at the Federal German universities during the past 10 years includes scientific papers and monographs as well as research projects. In addition, a list of theses submitted by candidates wishing to qualify for lecturing at a German university ("Habi,-litationsschrift") has been set up for the same period. The emphasis is on psychosomatic/psychotherapeutic care, specific psychosomatic diseases and the management of chronic diseases, whereas less research activity was seen in the areas of psychophysiology and epidemiology. The data represent considerable research activity in this discipline, but it would be advisable to see to it that in the future such data are better documented and coordinated.

Germany, West↗
PubMed1990

[The mechanisms of elimination of o-125I-benzoate in rabbits].

An analysis of the mechanisms of elimination of o-125I-benzoate in the rabbit kidney on the basis of the inhibition of the secretionary transport by probenecid has shown that o-125I-benzoate is eliminated in the kidneys not only by glomerular filtration but by tubular secretion as well. An effect on the total amount of the drug excreted in the urine is exerted by tubular resorption (apparently by the process of passive diffusion), which exceeds tubular secretion. A comparison of the chromatograms of the plasma and urine before and after the competitive inhibition of the tubular active transport by probenecid revealed a higher share of o-125I-benzylglucuronide in the urine in the case of inhibition. The results suggested a partial share of the kidneys in total biotransformation of o-125I-benzoate. Excretion of the original drug and metabolites in the bile forms a negligible share (less than 1%) of total clearance in rabbits.

Animals↗
PubMed1990

[Hypertension outpatient clinic for children and adolescents. Analysis of nearly 10 years of monitoring].

314 children with hypertension living in an urban district have been transmitted to our out patient clinic. These children were discovered by regularly performed examinations of the medical youth care since 1979. We found a secondary cause of hypertension in 2.2 per cent. Risk factors, as for example familiar disposition, hyperlipidaemia, smoking and overweight, were also analysed. A dynamic exercise-test was performed by means of bicycle-ergometry. 43 per cent of the children with elevated blood pressure in rest reacted with hypertension during exercise. Criteria for drug-therapy were the unsuccessful non-medicamentous effects on the hypertension and a hypertension exercise-test. After 2-5 years 55.9 per cent of all children with elevated blood pressure of the beginning of our study became normotensive without drug-therapy.

Adolescent↗
PubMed1990

[Ergometric exercise tests in the diagnosis of juvenile hypertension].

We analysed 186 exercise stress-tests in children and adolescents with juvenile hypertension. 40 per cent of our patients showed an exaggerated rise of blood pressure during ergometric testing. There were no severe complications during exercise-tests. We recommended an antihypertensive drug therapy in cases of hypertensive resting blood pressure and hypertensive exercise-test. The ergometric investigation can control the effectiveness of drug therapy. Our data documented that 53.5 per cent showed a spontaneous remission of their elevated blood pressure after 3-5 years. There was no statistical dependence on the exaggerated rise of blood pressure during dynamic exercise-test.

Adolescent↗
PubMed1989

Expression of nonspecific cross-reacting antigen species in myeloid leukemic patients and healthy subjects.

The reactivity of two monoclonal antibodies recognizing NCA-95 and NCA-55 (MAb 47 and MAb 192, respectively) with a polyclonal anti-NCA serum in myeloid leukemic cells isolated by density gradient centrifugation was compared using an immunofluorescence test (IF). It was observed that the blood myeloid cells in 78.8% of the patients with different types of myelocytic leukemias and all granulocytes of 15 normal donors showed similar expression of the NCA species studied. The leukocytes of the remaining patients did not synthesize the NCA-95 species regardless of the maturation stage of the cells studied. In two patients, synthesis of this NCA form was limited to the fractions containing myelocytes and metamyelocytes. We have found that all anti-NCA antibodies studied recognized different antigenic epitopes in a myeloid cell series. A relationship between the patient's survival and the proportion of NCA-containing cells was also observed.

Antibodies, Monoclonal↗
PubMed1989

Analysis of elimination mechanisms of some 99mTc-complexes.

The biological behaviour of complexes of 99mTc with aminopolycarboxylic and aminocarbohydroxamic ligands EDTA (ethylenediaminetetraacetic acid), DTPA (diethylenetriaminepentaacetic acid), EDTAH (ethylenediaminetetraacetohydroxamic acid) and HIDAmH (N-2-hydroxyethyl-N-carboxymethyl-aminoacetohydroxamic acid) was studied in rabbits. The pharmacokinetic parameters determined in intact rabbits were compared with the results obtained in the study of renal and hepatic clearance of the complexes under study. Hepatobiliary excretion, which in [99mTc]EDTA forms 20-30% of the total excreted amount, is of negligible magnitude in the other 99mTc-complexes studied (less than 2%). Their renal clearance is not influenced by the inhibition of tubular secretion with probenecid. Binding to plasma proteins increases in the order [99mTc]DTPA less than [99mTc]EDTA less than [99mTc]HIDAmH less than [99mTc]EDTAH and the elimination half-life increases in the same order. The value of renal clearance of the complexes studied related to inulin clearance correlates well with the fraction of the free drug in the plasma. In rabbits the complexes under study are excreted mainly by the mechanism of glomerular filtration in the kidney.

Animals↗
PubMed1989

A comparison of nerve conduction velocities and current perception thresholds as correlates of clinical severity of diabetic sensory neuropathy.

Nerve conduction velocities (NCVs) are the standard measurements used to confirm the presence or absence of diabetic neuropathy. NCVs were contrasted with the newer technique of measurement of alternating current perception thresholds (CPTs) in assessing the quantitative level of correlation with severity of diabetic sensory neuropathy. A very detailed, scored neurological history (symptoms) and physical examination, emphasising sensory assessment, was conducted on 71 individuals with diabetic neuropathy of varying degrees of severity. Sensory and motor NCVs and CPTs at 5, 250, and 2000 Hz of the upper and lower extremities were determined for these individuals. In addition, vibration thresholds (VTs) were measured as a third modality. Twenty eight individuals underwent repeated evaluations at 2, 6, 10 and 12 months after the initial procedures. Using the results of 169 complete evaluations, correlations were determined between physical scores (PS) and symptoms scores (SS) and NCVs. NCV correlations with the SS were weaker than with the PS. The strongest of the correlations were found between the PS and motor NCVs of the median nerve (rho = 0.29) and the tibial nerve (rho = 0.38). Normal NCVs were present in the face of very significant historical and physical abnormality. Correlations of the SS and PS with both VTs and CPTs were higher than with the NCVs. CPTs proved the more effective as predictors of both symptomatic and physical impairment. NCVs appear to lack the resolving power necessary to evaluate subtle differences in clinical state of diabetic sensory neuropathy. The supplementary use of current perception testing may improve the quantitative assessment of this condition.

Arm↗
PubMed1989

Effect of substance P on catecholamine secretion from rat adrenal medulla in situ.

Splanchnic nerve stimulation caused a frequency-dependent increase in catecholamine (CA) secretion with a maximum at 10 Hz from adrenal medulla of WKY rats in situ. Substance P (SP(1-11)) had no effect on the basal output of CA. During nerve stimulation, however, SP(1-11) decreased only the adrenaline (A) secretion by 18% at 10 Hz and by 55% at 20 Hz (p less than 0.05), whereas the noradrenaline (NA) secretion remained unchanged. These results provide further evidence that SP(1-11) may modulate frequency-dependently the secretion of CA from adrenal medulla in situ.

Adrenal Medulla↗