Search PubMed⌕ Search

Biomedical subjects

R Richter

Publications and source records attributed to R Richter.

At least 73 records · Page 4Linked to original sources
PubMed1995

[Vitreous involvement in cytomegalovirus retinitis].

In our outpatient department we often see patients with vitreous inflammation. Recent reports emphasize that vitreous inflammation is very rare, so we looked for patients with cytomegalovirus (CMV) retinitis and vitreous inflammation. We investigated 359 HIV-positive patients for at least 1 year; all patients reached the stage of AIDS disease. We included patients without any retinal signs of CMV retinitis at the beginning or CMV recurrence during the study. A slit-lamp investigation, binocular funduscopy and b-picture ultrasound were done at regular intervals. The results show an increase in vitreous inflammation with the frequency of CMV retinitis recurrences. Patients very often develop retinal detachment. Vitreous inflammation is a critical factor when examining CMV retinitis. In the future a larger series of patients should be examined.

AIDS-Related Opportunistic Infections↗
PubMed1994

Plasmids designed to alter the antibiotic resistance expressed by insertion mutations in Bacillus subtilis, through in vivo recombination.

Numerous insertion mutations conferring resistance to antibiotics are available in Bacillus subtilis. However, many of them have been constructed in vitro by inserting genes from the Staphylococcus aureus plasmids, pC194 or pE194, conferring resistance to chloramphenicol (Cm) or erythromycin (Er). Others are insertions of the Enterococcus faecalis Tn917 transposon conferring resistance to Er. This paucity of resistance markers has been limiting the possibilities of constructing and studying mutants carrying two or more of these mutations in the past. We constructed plasmids which can be used to change the antibiotic resistance expressed by preexisting chromosomal insertions, through transformation and homologous recombination. These vectors replace the pre-existing resistance to Cm or Er with new resistances to neomycin (Nm), phleomycin (Pm), spectinomycin (Sp) or tetracycline (Tc).

Bacillus subtilis↗
PubMed1994

Easy cloning of mini-Tn10 insertions from the Bacillus subtilis chromosome.

Delivery vectors for mini-Tn10 transposons function in Bacillus subtilis (M. A. Petit, C. Bruand, L. Janniére, and S. D. Ehrlich, J. Bacteriol. 172:6736-6740, 1990). Using this system, we identified a new gene (sytA) whose inactivation affected regulation of genes of sucrose metabolism. For cloning the sytA::Tn10 insertion in Escherichia coli, we developed a methodology similar to that commonly used for B. subtilis Tn917 insertions. We constructed a plasmid which can be used to insert (by in vivo recombination) a ColE1 origin linked to a spectinomycin resistance gene (ori-spc element) into mini-Tn10 transposons inserted into the B. subtilis chromosome. DNA extracted from a sytA::Tn10::ori-spc transformant was cut with restriction enzymes that do not cut into the Tn10::ori-spc sequence; plasmids containing the sytA::Tn10 insertion were cloned by self-ligation, followed by transformation of E. coli. To obtain the wild-type sytA region, one of these plasmids was ligated with an E. coli-B. subtilis shuttle vector conferring erythromycin resistance, and the hybrid was used to transform the wild-type B. subtilis strain. Erythromycin-resistant transformants, detected as spectinomycin sensitive, resulted from conversion of the insertion mutation by the resident wild-type locus. The shuttle plasmid containing the wild-type locus could then be recovered in E. coli.

Bacillus subtilis↗
PubMed1994

[Ophthalmologic manifestations in early and late stages of AIDS].

In a prospective study of 101 patients with HIV infection and a medium CD4 lymphocyte cell count of 350 x 10(6)/l and a retrospective study of the records of 79 AIDS patients, we compared the first ocular symptoms in HIV-infected patients to the CD4 count. In Walter-Reed stages 2-4 (n = 101) we found sicca syndrome in 9.2%, in 52% lens opacities in the cortex and only in less than 1% HIV-related angiopathy of the retina. In Walter Reed stages 5-6 (n = 79), 26% of the AIDS patients developed CMV retinitis, 33% HIV angiopathy of the retina and only 1% retinal toxoplasmosis. The average CD4 lymphocyte cell count was never better than 100 x 10(6). Lens opacities in HIV-infected patients could be an early ophthalmological symptom of HIV infection.

AIDS-Related Opportunistic Infections↗
PubMed1994

[Subjective stress factors and dyspnea in asthma patients over time].

The share of psychological factors involved in the disease pattern of asthma bronchiale is considered to be about one to two thirds, according to the literature. It is only rarely that a distinction is made between causative psychogenetic factors and such factors that exercise an influence on the course of the pattern of symptoms. The aim of the present study was to cover prospectively the possible--including the psychological--parameters influencing the pattern of symptoms of asthma in relation to time. To this end a symptom diary was kept for 35 asthma patients for an average time of 8 weeks. The entries were made daily. The points noted and counted were the concurrent occurrence of dyspnoea and various subjective influencing factors such as everyday stress, weather, etc. or their coincidence with a time lag of one day. There were surprisingly few links between dyspnoea and mental stress/stressors in relation to time. On the other hand, there was a high coincidence in relation to impairment of the quality of life and to a lesser extent also in relation to subjectively experienced weather and local conditions. The results show that stress factors--contrary to the aetiological beliefs held by laymen--are not represented by a simple relationship between psyche and asthma as time-concurrent or time-lagging coincidences to shortness of breath. However, clarification of complex socio-psychosomatic linkups in the psychogenesis of asthma bronchiale were not the subject of this study.

Adaptation, Psychological↗
PubMed1994

["The most ill go into psychoanalytic treatment"? Critical comments on an article in Report Psychologie].

Thomas and Schmitz claim that they "deliver a proof for the effectiveness of humanistic methods" (p. 25) with their study. However, they did not or were not able to verify their claim due to several reasons: The authors did not say if and if so to what extent the treatments carried out within the framework of the TK-regulation were treatments using humanistic methods. The validity of the only criterium used by the authors, the average duration of the inability to work, must be questioned. The inferential statistical treatment of the data is insufficient; a non-parametrical evaluation is necessary. Especially missing are personal details concerning the treatment groups (age, sex, occupation, method, duration and frequency of therapy), which are indispensable for a differentiated interpretation. In addition there are numerous formal faults (wrong quotations, mistakes in tables, unclear terms etc.). In view of this criticism we come to the conclusion that the results are to a large degree worthless, at least until several of our objections have been refuted by further information and adequate inferential statistical methods. This study is especially unsuitable to prove a however defined "effectiveness of out-patient psychotherapies", therefore also not suitable to prove the effectiveness of those treatments conducted within the framework of the TK-regulation and especially not suitable to prove the superiority of humanistic methods in comparison with psychoanalytic methods and behavioural therapy.

Ambulatory Care↗
PubMed1993

Clinical evaluation of a respiratory resistance biofeedback training.

This study evaluated the effectiveness of a respiratory resistance biofeedback training. Fifteen adult asthmatic subjects participated in a feedback training program including twelve feedback sessions (three sessions weekly). Respiratory resistance (Ros) was measured using the forced oscillation method; to prevent subjects from lung hyperinflation, feedback was interrupted when functional residual capacity increased. One-second forced expiratory volume (FEV1), usage of self-administered medication, degree of asthmatic dyspnoea, and general activity were daily recorded in symptom diaries for at least three months, starting four weeks before the first feedback session. Seven subjects showed significant average Ros decreases within the sessions, while mean Ros in two subjects was increased. However, these direct feedback effects were not related to transfer effects outside the laboratory: e.g., not one of the seven successful subjects showed FEV1 improvements, and only in one of them were within-session Ros reductions accompanied by a decreased frequency of self-administered medication during the training period. These results lead to the conclusion that Ros feedback may not be an effective technique for the treatment of bronchial asthma in adults.

Adult↗
PubMed1993

Diagnosis of veno-occlusive disease of the liver by color-coded Doppler sonography.

In a girl with bilateral Wilms' tumor veno-occlusive disease occurred during chemotherapy. The diagnosis was established by reversed flow in the portal vein displayed by color and pulsed Doppler sonography. After successful conservative treatment normalization of flow in the portal vein could be shown by both Doppler techniques.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1993

[Native radiologic staging of osteoporosis--CT densitometry of lumbar vertebral spongiosa. A correlation study].

Lumbar spine radiographs in 47 patients with manifest or clinically suspected osteoporosis were evaluated, using a staging system, and correlated to quantitative computed tomography (QCT) of lumbar vertebrae. The accuracy of osteoporosis assessment, obtained with plain film analysis, was 60%, the sensitivity 67%, the specificity 56%. Statistical correlation showed high standard deviation of each of the QCT-mean values according to the respective stage groups, and altogether poor linear correlation between increasing morphological stages of osteoporosis and decreasing QCT-values. As our results show plain film differentiation of normal from reduced trabecular bone mineral content is unreliable, even by use of a staging system. The diagnostic value of spine radiographs therefore remains limited to demonstration of advanced osteoporotic changes.

Absorptiometry, Photon↗
PubMed1993

Relaxing actions of corticotropin-releasing factor on rat resistance arteries.

1. Although it well established that corticotropin-releasing factor (CRF) injected i.v. can cause hypotension and vasodilatation, there is no in vitro evidence that CRF acts as a vasodilator. We have therefore tested the hypothesis that the hypotensive effect of i.v. CRF is due to a direct vasodilator action by carrying out experiments in vitro on rat resistance arteries (i.d. 150-300 microns). 2. Initial in vivo experiments confirmed that CRF (1.5 nmol.kg-1) injected i.v. caused hypotension in rats, this being partially antagonized by the CRF analogue CRF9-41. 3. For the in vitro experiments, vessels were taken from the mesenteric, cerebral and femoral vascular beds, and mounted as ring preparations in an isometric myograph. The vessels were pre-contracted with one of 3 agonists (prostaglandin F2 alpha, arginine vasopressin or noradrenaline) or with a high-potassium solution (K+). 4. With maximal concentrations of the agonists, CRF caused relaxation of mesenteric and cerebral vessels with 10 nM, and near complete relaxation with 100 nM. Femoral vessels pre-constricted with agonists and all vessels pre-constricted with K+ were less affected by CRF. In the mesenteric vessels, with sub-maximal levels of pre-constriction, CRF caused substantial relaxation at 1 nM and could cause complete relaxation at 10 nM. 5. The relaxant effect of CRF on contractions of mesenteric vessels was antagonized by 100 nM CRF9-41. Neither tetraethyl ammonium (30 mM) nor glibenclamide (3 microM) antagonized the relaxant effect of CRF. 6. The relaxant effect of CRF on mesenteric small arteries was found to be unaffected by removal of the endothelium. 7. The results indicate that CRF causes an endothelial-independent vasodilatation of rat resistance arteries under in vitro conditions at concentrations which are consistent with this being an important cause of the hypotension observed with i.v. injection of CRF.

Animals↗
PubMed1993

Carcinoembryonic antigen isotypes in tissue sections and loose cyst fluid cells of ovarian neoplasms.

The aim of this study was to establish whether different subsets of ovarian neoplasms express a restricted isotype of carcinoembryonic antigen (CEA) which can be detected in solid tumors and detached cells. Sixty-one cases of mucinous, serous, endometrioid, and Krukenberg tumors were studied by immunohistochemistry using two monoclonal antibodies (MAbs), commercial anti-CEA and D14 with a higher specificity for colorectal adenocarcinomas. The results with both antibodies showed a considerable degree of heterogeneity between cases of nonserous tumors, with a more restrictive pattern observed with the D14 MAb. The proportion of immunostained cells was comparable in tumors and fluids.

Adenocarcinoma↗
PubMed1993

The relationship between neuroticism and blood pressure reexamined. An investigation of a nonclinical sample of military conscripts.

Given the contradictory results reported in the literature on the relationship between neuroticism and blood pressure, it was decided to reexamine this topic. This was done with a large sample very homogeneous for age, sex, food intake and life style and basically unselected in terms of medical history. In the frame of a blood donation program blood pressure was measured in 810 conscripts. In addition, subjects completed either form A or form B of the Eysenck Personality Inventory (EPI). Data from a total of 624 subjects were suitable for evaluation. No significant correlations were obtained between systolic or diastolic blood pressure and scores of neuroticism or extraversion (r = -0.10 to 0.06) nor did groups with different blood pressure values differ substantially in terms of these variables. This supports work showing that there is no essential connection between blood pressure and emotional lability as measured by the EPI.

Adult↗
PubMed1993

[Echocardiography studies of children and adolescents with primary hypertension].

We evaluated 100 schoolboys and schoolgirls whose blood pressure levels were above the 90th percentile. To determine whether in childhood left ventricular hypertrophy can be induced by pressure overload, we measured the thickness of the interventricular septum and posterior wall of the left ventricle and calculated the left ventricular muscle mass. Compared with a normotensive control group the thickness of the septum and posterior wall was significantly higher in children with elevated blood pressure. The normal range of the wall thickness was not exceeded. Furthermore, the left ventricular muscle mass differs between the two groups. 13 per cent of the hypertensive children had a greater ventricular mass than two standard-deviations from the normotensive group. This signifies an adaptation to the haemodynamic effect on the increased blood pressure.

Adolescent↗
PubMed1993

[Digoxin-like immunoreactivity in newborn infants--a pitfall of digoxin therapy?].

Endogenous digoxin-like immunoreactive substances (DLIS) show crossreactions with different immunoassays used for digoxin drug monitoring. In 61 blood samples of 47 eutrophic healthy newborns with jaundice, digoxin serum concentrations were measured during examination of serum bilirubin using a digoxin polarisation immunoassay. Although there was no digoxin therapy in any case, we found positive serum digoxin immunoreactivity (> or = 0.2 ng/ml) in 86% of serum samples. The mean DLIS-concentration was 0.43 +/- 0.19 ng/ml with a maximum of 0.9 ng/ml. We found a significant indirect correlation (rs = -0.34; p = 0.05) between age and serum DLIS concentration. A case report demonstrates the possibility of DLIS interference on digoxin drug monitoring.

Blood Proteins↗