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Biomedical subjects

R Hein

Publications and source records attributed to R Hein.

107 records · Page 6Linked to original sources
PubMed1984

Effect of retinoids on collagen production by chondrocytes in culture.

The effect of vitamin A and of some of its derivatives on chondrocytes in culture has been studied. In the presence of retinoids the proliferation of the cells decreased and they lost their characteristic polygonal shape and assumed a fibroblast-like morphology. All retinoids also caused dedifferentiation of chondrocytes as indicated by the induction of types I and III collagen. 13-cis retinoic acid (= isotretinoin) was the most active derivative in this aspect. Since appropriate control of the synthesis of extracellular matrix proteins is a prerequisite for their normal physiological function, alterations such as those observed here may be involved in the pathogenesis of side effects which are observed during the treatment of dermatological disorders with retinoic acid derivatives.

Animals↗
PubMed1984

Effect of vitamin A and its derivatives on collagen production and chemotactic response of fibroblasts.

Vitamin A and several other retinoids were added to fibroblast cultures in order to study possible alterations in biochemical properties and cellular responsiveness. The proliferation of cells was inhibited as the concentration of retinoids increased from 10(-9) to 10(-5) mol/l. Synthesis of non-collagenous proteins and production of both type I and type III collagen were decreased. The onset of type III collagen synthesis by tendon fibroblasts in culture was delayed. Furthermore, the chemotactic response of fibroblasts to fibroblast-conditioned medium was markedly reduced in the presence of retinoids (10(-6) to 10(-12) mol/l).

Acitretin↗
PubMed1978

An outbreak of plague in Hlegu, Burma in 1977.

An outbreak of plague occurred in Hlegu Town, Burma in February and March 1977. Altogether 14 bubonic plague cases, with 2 deaths were reported, mostly children under 15 years of age. Twice as many males as females were affected. A retrospective investigation showed that a rat fall took place in the last week of January. Only 9.5% of the rodents which died in the epizootic were found to be infected with Y. pestis; this apparent low infection rate probably resulted from the inclusion in the survey of some dead rats which died of other causes. 14.5% out of 48 trapped rodents were found to be serologically positive. The general flea and cheopis indices were rather high, perhaps because fleas were found to be partially resistant to DDT and also because spraying of insecticide did not effect fleas on the hosts. The cheopis index in Hlegu Town was 1.17, and less than 0.5 in Hlegu suburb (Yankin-Yat) where no epizootic was reported. An active case search revealed 76 suspected plague cases out of which 11 were found to have bubonic plague. A field trial showed that plague vaccination during the outbreak did not result in a rise of detectable antibodies in persons inoculated.

Adolescent↗
PubMed1975

Restriction of beta-adrenergic responsiveness in hypertrophied hearts of chronically isoproterenol-treated rats.

A single subcutaneous dose (1 mg/kg) of isoproterenol (ISO) increases the net calcium-45 uptake into the ventricular myocardium of normal rats by a factor of 3 to 4 within 6 hr. When the same dose of ISO was administered to rats previously treated with 1 mg ISO/kg per day for 1--3 weeks, this rise in labeled Ca-uptake was greatly reduced. Consequently the stimulatory effect of ISO on the Ca-dependent high-energy phosphate consumption was considerably diminished. Furthermore the chronic application of ISO produced a hypertrophy of both ventricles. When this treatment was discontinued for 7 days the ventricular weights returned to normal, whereas the restriction of beta-adrenergic reactivity persisted for more than 3 weeks. The results indicate that the decrease in responsiveness to beta-adrenergic agents is not due to the hypertrophy itself but must be considered to be an independent phenomenon-possibly resulting from adaptation to chronic beta-adrenergic overstimulation.

Adenosine Triphosphate↗
PubMedDate not supplied

Patent foramen ovale and left atrial appendage: new devices and methods for closure.

Transcatheter closure of atrial septal defects (ASDs) has become a routine procedure in many countries of the world. It spares many patients cardiac surgery and has proven efficacy in long-term studies. Device improvements have resulted in a continuous reduction of complications and of residual shunt frequency. ASD closure devices are also used for transcatheter closure of patent foramen ovale (PFO) for prevention of paradoxical embolism. In the past few years, there has been increasing interest in developing devices specifically designed for PFO closure. Although transcatheter closure of ASDs is well established, interventional closure of the left atrial appendage is in its development stage. Closure of the left atrial appendage is designed to reduce the risk of stroke in patients with atrial fibrillation in whom anticoagulation with Warfarin-type drugs is contraindicated. This article describes the latest developments in catheter closure of PFO and the left atrial appendage.

Atrial Appendage↗
PubMedDate not supplied

Effects of mometasone furoate on human keratinocytes and fibroblasts in vitro.

The long-term treatment of inflammatory skin diseases with topical glucocorticoids is limited by their side effects such as skin atrophy, delayed wound healing and striae distensae. Mometasone furoate (MF) is a newly synthesized glucocorticoid with the advantage of increasing efficacy and reducing the number of adverse effects. The aim of our study was to compare the effects of MF and conventional fluorinated corticosteroids on a human keratinocyte cell line (HaCat) and human skin fibroblasts in vitro. Monolayer cultures of these cell lines were exposed to different concentrations of the active compounds for 5 days to analyze the influence on morphology and proliferation. Chemotaxis of HaCat cells and fibroblasts was studied in blind-well Boyden chambers using collagen type I and fibroblast-conditioned medium as a chemoattractant. Additionally, fibroblasts were used to investigate the contraction of collagen gels since lattice contraction appears to model the contraction of skin wounds. All glucocorticoids tested influenced fibroblast and keratinocyte proliferation in a dose-dependent manner, yet the effect was clearly more marked with fluorinated corticosteroids than with MF. Similar effects were obtained using the chemotaxis assay. At low concentrations (10(-9) M) MF exerted almost no influence, while the conventional fluorinated substances inhibited direct migration significantly. Contraction of collagen gels was inhibited completely by betamethasone valerate at high concentrations (10(-5)-10(-3) M), but only partially inhibited by MF at its highest concentration (10(-3) M). Although MF reveals high anti-inflammatory activity similar to that known for conventional fluorinated derivatives of corticosteroids, the study shows that MF has less effect in the tested in vitro systems. Therefore, it remains to be seen whether these data might indicate the possibility of a dissociation between the inflammatory activity and the inhibition of the biosynthetic capacities of fibroblasts and keratinocytes by modification of the steroidal structure of corticosteroids.

Administration, Topical↗
PubMedDate not supplied

Comparison of two prognostic markers for malignant melanoma: MIA and S100 beta.

It has recently been shown that the serum level of melanoma-inhibitory protein (MIA) provides useful information for the therapy and follow-up of patients with malignant melanoma. Previously, S100 beta has been described as a useful tumor marker for malignant melanoma. In this study, we compare the significance of the two markers in follow-up, therapy outcome and prognosis by measuring MIA and S100 beta serum levels in 50 melanoma patients. Serum levels were measured in patients with malignant melanomas of stages I-IV with at least 3 time points of measurement. Serial MIA and S100 beta measurements were obtained from 32 patients with stage IV disease in parallel to chemotherapy and from 18 patients with a history of stage I and stage II disease during follow-up. The response to chemotherapy in stage IV disease and relapse of melanoma during follow-up correlated with changes in MIA and S100 beta serum levels. In comparison, MIA revealed slightly higher specificity and sensitivity. In conclusion, both markers are useful for detection of progression from localized to metastatic disease during follow-up and for monitoring therapy of advanced melanomas.

Adult↗
PubMedDate not supplied

MIA, a novel serum marker for progression of malignant melanoma.

MIA was isolated previously as a small soluble protein secreted from malignant melanoma cell lines in vitro. Highly restricted expression patterns in melanocytic tumors were identified in vivo. We therefore quantitated serum levels of MIA protein by means of a non-radioactive ELISA and investigated whether MIA provides clinically relevant parameters in patients with malignant melanomas. Here we report enhanced MIA serum levels in 13% and 23% of patients with stage I and II disease, respectively, and in 100% with stage III or IV disease. Response to therapy in stage IV disease correlated with changes in MIA serum levels and surgical removal of metastases led to normalization of serum values. Repeated measuring of sera from 350 patients with a history of stage I or II melanoma during follow-up, we detected 32 patients developing positive MIA values. At the time of serum analysis 15 of them had developed metastases and one presented with metastatic disease 6 months later. In conclusion, MIA represents a novel serum marker for systemic malignant melanoma revealing the highest sensitivity and specificity among currently available markers.

Adult↗
PubMedDate not supplied

MIA as a reliable tumor marker in the serum of patients with malignant melanoma.

BACKGROUND: Reports published in 1996 concerning the protein MIA proposed it as a useful tumor marker for patients suffering from malignant melanoma. Therefore we systematically started to measure MIA levels in patients with malignant melanoma. It was and still is questionable whether MIA in the serum of melanoma patients is a reliable tumor marker in terms of course of disease, therapy-monitoring and prognostic value. Previous studies have already confirmed the specifity of MIA as a tumor marker for malignant melanoma. MATERIALS AND METHODS: Using an ELISA- System, we examined over 830 blood samples of 326 melanoma patients. The cut-off was determined at 9.8 ng/ml. RESULTS: 5.6% (n = 17) of melanoma patients at stage I/II (n = 302) showed increased MIA levels, whereas at stage III/IV (n = 5/n = 19) high levels were found in 60.0% and 89.5% respectively. Patients at stage III/IV with MIA levels below the cut-off turned out to be the ones after metastatic surgery, irradiation or chemotherapy. None of these patients developed further metastases during follow-up, just as patients at stage I/II without increased MIA levels. After a distinct rise of MIA levels, metastases could be detected at the same time or shortly after. On the other hand we saw decreasing levels after or during therapy. CONCLUSION: Our data showed that MIA is a suitable serum marker to detect metastases and to monitor course and therapy of disease. The prognostic value (increased MIA levels at stage I/II), however, requires further investigation.

Antigens, Tumor-Associated, Carbohydrate↗
PubMedDate not supplied

[Mollicutes in male infertility: is antibiotic therapy indicated?].

Mollicutes are frequently isolated from sperma of infertile men. The potential effect on the fertility of mollicute infection is controversial as is antibiotic therapy. In our andrological patients, the prevalence of mollicutes is approximately 10%. To evaluate the benefit of antibiotic therapy, we investigated two groups of patients: group 1-patients with positive or negative mollicute cultures and normal spermiogram; morphological changes on spermatozoa were particularly evaluated (n = 40); group 2 - patients with positive mollicute cultures treated with doxycycline or erythromycin. Sperm parameters were analysed before and after treatment (n = 20). When infected and non-infected sperma from group 1 were compared, the only difference found was an alteration of the sperm tail (p less than 0.005). Light microscopy and electron microscopy (EM) often revealed coiled tails which were probably due to adhesion of mollicutes (EM). The most frequently observed pathology in group 2 was found in patients with teratoasthenozoospermia. Compared with the post-therapy spermiogram, a significant difference was only observed in spermatozoal morphology (p less than 0.005). Therefore, we conclude that mollicutes produce important alterations in the human spermatozoal morphology, especially in the tail which appears in a spiral form. Since teratozoospermia is considered to be an important factor of infertility in man, antibiotic therapy is recommended in cases of mollicute involvement.

Bacteria↗