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Biomedical subjects

R Brinkmann

Publications and source records attributed to R Brinkmann.

58 records · Page 4Linked to original sources
PubMedDate not supplied

Detection of SIV in rhesus monkey thymus stroma cell cultures.

To clarify the pathogenesis of SIV-induced thymus atrophy, the presence of SIV within thymus stromal cell cultures (epithelial cells, IDC, macrophages or fibroblasts) was investigated. The material studied consisted of 15 thymus specimens of rhesus macaques infected with SIVmac251 (2-4 months postinoculation). No viral antigen was detected, either in the cultures, by immunohistochemistry, or in cell culture supernatants, by ELISA (p17 antigen), and no viral RNA was detected by in situ hybridization. Only after coculture with the C8166 cell line, was virus detected in 2 out of 15 stroma cultures. The fact that the virus could only be detected after several passages of coculture with the C8166 cell line indicates that the virus exists in the thymus stroma cells in the form of proviral DNA. The infection of thymus stromal cells may contribute to the destruction of the thymus microenvironment and to the SIV-induced thymus atrophy.

Animals↗
PubMedDate not supplied

Corneal endothelial cell damage after experimental diode laser thermal keratoplasty.

PURPOSE: To evaluate the safety of diode laser thermal keratoplasty (LTK) with respect to corneal endothelial cell damage. METHODS: In an in vitro animal model system, porcine eyes were irradiated with a continuously emitting laser diode at wavelengths (lambda) of 1.85 or 1.87 microm, corresponding to an absorption coefficient (micro(a)) of 1.1 or 2.0 mm(-1). Different irradiation and application parameters were tested serially. To determine the temperature threshold for endothelial damage, corneal buttons were analyzed separately in a waterbath experiment. The endothelial damage was assessed after trypan blue and alizarin red supravital staining under light microscopy. RESULTS: The thresholds for the 50% probability of thermal damage (ED50) were determined at corneal temperatures of 65 degrees C for a 10-second water-bath immersion, and 59 degrees C for 60 seconds. Coagulations that reached the deeper stromal layers revealed severe endothelial cellular alterations and areas of exposed Descemet's membrane. The thermally induced changes were dependent on laser power and the absorption coefficient (wavelength). Mean diameter of total endothelial cell damage was 245 +/- 154 microm (range, 0 to 594 microm) for an absorption coefficient of 1.1 mm(-1). The maximal lateral extent of endothelial cell damage induced by the laser exposure was 594 microm in diameter. Increasing the absorption coefficient decreased the penetration depth of the laser irradiation, creating a greater temperature rise within the corneal stroma and significantly less endothelial damage (P < .01), when the same laser power was applied. The calculated total area of damage for the paracentral human corneal endothelium ranged from 1.8% to 13.6%. CONCLUSION: Data obtained in this in vitro study were transferred to an endothelial cell damage nomogram, demonstrating that appropriate parameter improvements can minimize the adverse effects to the corneal endothelium. However, model adjustment to the human cornea indicates the potential for endothelial cell damage after diode laser thermal keratoplasty, and should be considered when performing this elective procedure.

Animals↗
PubMedDate not supplied

[Shortening diclofenac therapy by B vitamins. Results of a randomized double-blind study, diclofenac 50 mg versus diclofenac 50 mg plus B vitamins, in painful spinal diseases with degenerative changes].

The use of nonsteroidal anti-inflammatory drugs (NSAID) such as diclofenac for treatment of degenerative rheumatic disorders of the lumbar spine is of great significance in orthopedic practice. Clinical studies have shown that concomitant treatment with vitamins B1, B6, B12 and diclofenac provides more efficient pain relief than treatment using diclofenac alone. This study was undertaken in order to determine whether the duration of treatment with diclofenac for lower back pain can be shortened by adding B-vitamins to the therapeutic regimen. From September through December of 1986, 256 patients participated in a multicenter, controlled, randomized double-blind trial which compared the clinical efficacy of diclofenac (50 mg) with a combined therapy of diclofenac (50 mg) and vitamins B1, B6, and B12 (thiamine nitrate, pyridoxine hydrochloride, and cyanocobalamine, resp.; in dosages of 50 mg, 50 mg, and 0.25 mg, resp.). Patients were treated with 3 X 1 capsule daily for a maximum of two weeks, having the option to terminate participation in the trial after 1 week in the event of total pain relief. The data of 238 patients were able to be included in the evaluation. 29 patients opted to discontinue therapy due to remission on symptoms. Nineteen (65.6%) of these patients belonged to the combined therapy group, the other 10 (34.4%) having taken diclofenac alone; this difference is statistically significant (p less than 0.05). An important aspect in the evaluation of therapy was the patient response regarding the improvement of painful symptoms which, in addition to their subjective feedback, was reflected in the test results of the "Hoppe Pain Questionnaire (HPQ)." All parameters used as a measure of pain relief indicated superior results with the B-vitamin supplemented therapy when compared with results obtained with diclofenac alone. Moreover, after 3 days of therapy the "sensory" pain factor "sharpness" improved significantly. Undesirable side-effects were documented with 39 patients, 14 of them having discontinued therapy for this reason. No statistically significant difference could be determined within this group with regard to therapy. The study results document the positive influence of B-vitamins on painful symptoms and indicate that less NSAID is needed for pain relief when combined with B-vitamins.

Clinical Trials as Topic↗