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Biomedical subjects

R H Jindra

Publications and source records attributed to R H Jindra.

10 recordsLinked to original sources
PubMed1999

Antagonistic effects of combination photosensitization by hypericin, meso-tetrahydroxyphenylchlorin (mTHPC) and photofrin II on Staphylococcus aureus.

Photodynamic therapy involves the application of a photosensitizer activated by visible light to generate cytotoxic reactive oxygen. In addition to clinical investigations, in vitro studies concerning photodynamic potency of sensitizers as well as quantification of illumination procedures are necessary. In our investigation, the objective was to evaluate not only the effects of photosensitizer and light on Gram-positive Staphylococcus aureus, but also to investigate possible synergistic or antagonistic effects of these sensitizers. Therefore, we used hypericin, Photofrin II, porfimer sodium and meso-tetrahydroxyphenylchlorin (mTHPC) alone, as well as in combination. Log-phase cells of S. aureus exhibited a marked sensitivity to white thermal light irradiation in the presence of Photofrin II and mTHPC. However, hypericin caused a rather stimulated growth expressed in increased optical density (OD) and increase of total cell count (TCC) of the culture. Combination sensitization of S. aureus by Photofrin II and mTHPC with hypericin likewise caused a stimulation of bacterial growth. No synergistic effects were obtained by combination of Photofrin II and mTHPC; photoresponse of S. aureus was rather decreased by using combined porphyrins. In comparison, TCC and colony-forming units (CFU) were suppressed in the presence of mTHPC after an illumination procedure as well as in dark reactions. These effects were also obtained in the combination photosensitization by mTHPC and Photofrin II. In the presence the of hypericin, photodynamic effects of mTHPC and Photofrin II were inhibited. It was finally concluded that hypericin in our model is not a proper sensitizer for combination photo-sensitization due to antagonistic effects on photodynamic activity of mTHPC and Photofrin II.

Cell Culture Techniques↗
PubMed1999

Ambulant photodynamic therapy of superficial malignomas with 5-ALA in combination with folic acid and use of noncoherent light.

This study reports our first results of ambulant photodynamic treatment with 5-aminolevulinic acid (5-ALA) in combination with folic acid and subsequent illumination with a noncoherent light source. The compound was topically applied to avoid total body skin sensitivity which occurs in the case of systemic administration. If no therapeutic response could be proved, we added folic acid to 5-ALA for a further treatment attempt. Illumination was performed by broad band red thermic light to also excitate reaction products with absorption bands located near to that of the sensitizer. As a result, we observed a response in all cases, however, in some cases only after the addition of folic acid.

Administration, Topical↗
PubMed1996

Induratio penis plastica: effectivity of low-dose radiotherapy at different clinical stages.

This study describes the treatment of Peyronie's disease by means of low-dose radiotherapy. We treated 265 men aged 24.5-79.4 years (median = 57.7 years). No previous therapy had been carried out in 214 patients, and 41 patients had been pretreated (systemic: potassium p-aminobenzoate, vitamins a, b, e; topical: corticosteroids, teleradiotherapy). The disease was classified using criteria proposed by Alth in 1984 location, number and size of foci, hardness of fibromatous foci and axis deviation, potentia coeundi and pain were evaluated). Radiotherapy was performed by local application of a special iridium-192 moulage developed at our institute. In 66.4% of the monitored patient group (n = 155) therapy was successful. We obtained complete regression of the fibromatous foci in 9% (n = 14), partial remission > 50% in 29.7% (n = 46) and partial remission < 50% in 27.7% (n = 43) of the patients. We found a significant correlation between hardness, size of the treated foci and therapeutic success. Eighty-three patients suffered from pain during penile erection before therapy, and in 61.4% (n = 51) of these patients the pain disappeared after treatment. Moreover, the patients confirmed that both loss of pain and regression of deviation related to foci regressions were correlated with improvement in erectile function. No serious side effects were observed in any of our patients.

Adult↗
PubMed1996

Hypericin in phototherapy.

We describe the first local use of hypericin as photosensitizer for photodynamic therapy in a patient with recurrent malignant mesothelioma. Hypericin is a polycyclic quinone, which has been shown to possess in vivo and in vitro antiretroviral and photosensitizing activity; moreover, it is used in depressive disorders. The semiquinone radical, singlet oxygen, and superoxide anion radical are reported to be the toxic agents in hypericin phototherapy. Our first experience with locally applied hypericin in a superficial tumor-plate was performed 8 weeks after the systemic administration of hematoporphyrin derivatives. For tumor light illumination we used an argon pumped dye laser tuned to 632 nm. Owing to satisfactory results, we repeated the same therapy 4 weeks later- and no therapeutic effect was noted. Following this, we proved the interstitial application of HPD and the combination of interstitial HDP and superficially applied hypericin. The subsequent light illumination 6 hours later had no efficacy in the HDP-photosensitized area but there was tumor destruction in the field with both administered photosensitizers. Our first experience suggests a potentiation of two photosensitizers: hematoporphyrin derivatives and hypericin.

Aged↗
PubMed1994

Photodynamic therapy--an alternative pathway in the treatment of recurrent breast cancer.

PURPOSE: Validity of photodynamic therapy for treatment of recurrent breast cancer. METHODS AND MATERIALS: Patients were intravenously administered with a metal-free haematoporphyrine derivative for tumor sensibilization. For irradiation both monochromatic and white light was used. Monochromatic light at a wavelength of 632 nm was supplied by an Argon-Dye laser, whereas a halogen lamp provided white light. Narrowband red light came into use in case of one patient. Therapy included recurrent diseases of breast carcinoma, especially disseminary skin metastases, local recurrences, and lymphangiosis. Classical pretreatment was ineffective for the therapeuted patient group. RESULTS: The healing potency of photodynamic therapy for our patient group is enumerated in detail. No differences in the therapeutic effect were seen using either Argon Dye laser or noncoherent light sources. CONCLUSION: Photodynamic therapy appears to be a valuable treatment to classical therapeutic intervention providing a selective destruction of tumor cells without further affecting life quality.

Adult↗
PubMed1980

[Description of the electrocerebellogram by Parcor-coefficients (author's transl)].

The electrocerebellogram of the rabbit was analysed by the Parcor-coefficients. The results show that this bioelectrical activity may be described by two Parcor-coefficients. No changes in these coefficients were found under the influence of physostigmine or scopolamine. Differences between the rhythms induced by pentobarbital, harmaline and strychnine were established.

Animals↗
PubMed1976

Electroencephalogram spectral analysis by the direct and indirect methods: a comparison.

An artificially-created electroencephalogram was used to perform a comparison between the indirect and direct analysis methods. The results obtained by Fourier transform of the correlation function and smoothing of Fourier series development differ for a stochastic process in which the correlation functions are not sufficiently damped. Some mathematical framework is also appended in which the difference is worked out from a more theoretical point of view. In order to obtain results independent of inherent conditions, which in the simplest way can be detected by calculating the correlation functions, the indirect method is preferable.

Brain↗