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Biomedical subjects

G S Kistler

Publications and source records attributed to G S Kistler.

At least 19 recordsLinked to original sources
PubMed1997

Daytime serum levels of melatonin after topical application onto the human skin.

The hormone melatonin is produced in the pineal gland and secreted into the blood in a circadian rhythm. Due to its antioxidative and immunomodulatory effects it might play a role as a topical drug in dermatology. In this study we investigated the penetration kinetics of melatonin applied to the skin of 6 healthy volunteers aged 26-34 years (M/F = 2/4). First the individual physiologic daytime melatonin serum levels were determined by radioimmunoassay. Then 3 of the participants were treated once topically on their scalp with 20 mg melatonin dissolved in 70% ethanol, while the other 3 individuals received 100 mg. The application was performed at 9.00 a.m., and blood samples were collected repeatedly for a total of 8 h. Physiologic daytime melatonin levels in the 6 individuals were 16.8 +/- 10.0 pg/ml. The 3 individuals treated with 20 mg melatonin displayed peak serum levels of 762, 918 and 3,440 pg/ml, respectively, those treated with 100 mg melatonin showed peak levels of 1,136, 3,360 and 4,230 pg/ml lasting throughout the entire observation period of 8 h. These findings indicate that melatonin might accumulate in the stratum corneum with prolonged release into the blood system from this depot.

Administration, Topical↗
PubMed1997

Suppression of UV-induced erythema by topical treatment with melatonin (N-acetyl-5-methoxytryptamine). Influence of the application time point.

BACKGROUND: In a previous study, we reported a significant and dose-dependent suppression of UV-induced erythema in human skin by a topically applied melatonin preparation. OBJECTIVE: The present double-blind randomized study was designed to examine the influence of the application time point of topical melatonin on this antierythema effect. METHODS: Defined small areas on the lower back of 20 volunteers were treated with 0.6 mg/cm2 melatonin dissolved in a nanocolloid gel carrier either 15 min before or 1, 30 or 240 min after UV irradiation with twice the individual minimal erythema dose delivered by a Multiport Solar UV Simulator (UVA and UVB). The erythemata induced were evaluated by visual scoring and chromametry 24 h after irradiation. RESULTS: Treatment of the skin with melatonin 15 min before UV irradiation proved to almost completely suppress the development of an UV-induced erythema. In contrast, no significant protective effects of melatonin were observed when it was applied after UV irradiation. CONCLUSION: Topically applied melatonin has a clear-cut protective effect against UV-induced erythema. Free radical scavenging of UV-generated hydroxyl radicals and interference with the arachidonic acid metabolism are possible mechanisms of the melatonin action.

Administration, Topical↗
PubMed1996

Suppression of UV-induced erythema by topical treatment with melatonin (N-acetyl-5-methoxytryptamine). A dose response study.

Oxygen-centred free radicals play an important role in the pathogenesis of acute and chronic UV-induced skin damage as well as in skin aging. In this double-blind randomized study the efficacy of topically applied melatonin (N-acetyl-5-methoxytryptamine), a potent free radical scavenger, in the suppression of UV-induced erythema was assessed. A group of 20 healthy volunteers were irradiated with 0.099 J/cm2 UVB on four 5-cm2 areas on the lower back and topically treated with various concentrations of melatonin (0.05, 0.1, 0.5%) in a nanocolloid gel as carrier or with carrier alone. The UV-induced erythema was examined 8 and 24 h after irradiation by visual scoring and chromametry. A distinct dose response relationship was observed between the topical dose of melatonin and the degree of UV-induced erythema. Significant differences (P < 0.05) were found in redness (chromameter a-value and visual scoring) 8 h after irradiation between the areas treated with melatonin at 0.5% and those treated with melatonin at 0.05% or with the carrier. These results might open a new approach in the prevention and control of free radical-influenced skin diseases.

Administration, Topical↗
PubMed1980

[Burkitt's lymphoma in a Swiss patient].

In summer 1978, Burkitt lymphoma was diagnosed in a 23 year old Swiss male. A brief report on this patient appears justified for the following reasons: (1) Burkitt lymphoma is very rarely diagnosed in Switzerland. (2) The tumor cells of this patient could be established as a cell line. They have now been subpassaged in vitro for over 9 months. (3) In contrast to the majority of non-African Burkitt lymphomas, these tumor cells produce small amounts of Epstein-Barr virus.

Adult↗
PubMed1979

[Effect of 2 retinoids (vitamin A analogs) on human bronchogenic carcinoma in vivo (nu/nu mouse) and in vitro].

The antitumor effects of 2 aromatic retinoids (analogs of vitamin A) were investigated in human bronchogenic carcinomas grown in vitro and in vivo (serially transplanted in "nude" mice). In vitro, bronchogenic carcinoma cells treated with Ro 10-1670 (the free acid of an aromatic retinoid) displayed activation of the lysosomal system and increased cellular breakdown. In vivo, nu/nu-mice treated with Ro 10-9359 (the ethyl-ester of Ro 10-1670 showed inhibition of tumor growth. In the tumors, necrotic areas were intermingled with regions displaying a higher degree of keratinization as compared to those of the controls. The extracellular matrix surrounding the tumor cells of the retinoid-treated animals was increased in volume and electron density.

Animals↗
PubMed1979

[Isolation and in vitro cultivation of tumor cells from human bronchial carcinoma transplanted to the nu/nu mouse].

Isolation of pure human tumor cell lines from surgical specimens is still a difficult task. As a result, only a limited number of such cell lines is available for experimental and diagnostic work. In contrast, isolation of malignant cells from human tumors serially transplanted in "nude" mice offers many advantages. The amount of tissue obtainable is theoretically unlimited and the percentage of viable cells is usually much larger than in human surgical specimens. However, no simple and reliable technique for isolation and purification of nu/nu-mouse-grown human tumor cells has been available up to now. This preliminary communication describes such a method. Its applicability has been successfully tested on 4 human bronchogenic carcinomas from which pure tumor cell lines could be established.

Animals↗
PubMed1978

[Isolation of human tumor cells: conditions for in vitro diagnostic and therapeutic studies (proceedings)].

With a view to the possible use of human tumor cells for diagnostic and therapeutic tests (e.g. determination of hormone receptors, sensitivity to cytotoxic drugs, cytotoxicity tests), an attempt has been made to isolate and cultivate pure human tumor cell populations. 49 malignant effusions from 42 patients formed the starting material. The tumor cell isolation was carried out in three steps: 1. elimination of erythrocytes by density-gradient centrifugation or osmotic lysis with triple distilled water; 2. concentration of tumor cells by lg-sedimentation; 3. elimination of adherent cells by short term cultivation in plastic tissue culture flasks. This procedure yielded 95-98% tumor cells. From these suspensions of purified tumor cells, primary cultures were successfully established by supplementing the tissue culture media with autologous effusion fluid.

Cells, Cultured↗
PubMed1978

Inhibition of lactate dehydrogenase in cultured SIRC cells by cigarette smoke.

SIRC cell monolayer cultures were exposed to whole smoke from a mid tar and nicotine level research cigarette (ASFC, 72 puffs), or from a high tar and nicotine level reference cigarette (Kentucky 2RI, 48 puffs) over a period of 65 days. The activity and distribution of lactate dehydrogenase (LDH) in the cells were investigated, and the electrophoretic characteristics of its isozymes studied. Cell morphology was examined by light microscopy and by transmission- and scanning electron microscopy. LDH activity was reduced by exposure to smoke from both cigarette types, the greater inhibitory effect being produced by that of the Kentucky cigarette. In addition, cells exposed to this high tar and nicotine smoke displayed intramitochondrial granules which were larger and more numerous than those found in cells exposed to the mid tar and nicotine smoke, or in the control cells. It is speculated that cation accumulation in the mitochondria may be involved in the observed inhibition of LDH activity.

Cells, Cultured↗
PubMed1977

The activity and distribution of gamma-glutamyl transpeptidase (y-GT) in human lung cancers serially transplanted in nude mice.

Gamma-glutamyl transpeptidase (y-GT) activity and distribution were investigated in different types of human lung cancers (three epidermoid carcinomas, one large cell carcinoma) which were maintained by serial transplantation in nude mice. All transplanted tumour fragments were positive for the enzyme. In the epidermoid carcinomas, y-GT levels were related to the degree of tumour differentiation. Enzyme activity in tumour fragments was always higher than that found in normal adult human lung tissue, and was, in general, maintained throughout the transplantation series.

Adult↗
PubMed1977

[Hairy-cell leukemia with osteolytic bone changes].

Spontaneous bone fractures and/or focal osteolytic lesions were observed in three patients with morphologically and cytochemically confirmed hairy-cell leukemia 1-3 years after diagnosis and splenectomy. In a bone biopsy obtained from the body of the 12th thoracic vertebra light microscopy revealed a medullary osteopathy, the marrow cavities being infiltrated by a uniform population of rounded or slightly elongated cells. In addition, focal osteolytic lesions were observed on the trabeculae. Ultrastructurally, the cellular infiltrates consisted of reticulum cells, few mature and immature plasmocytes and numerous typical hairy cells with or without ribosome-lamella complexes. These observations demonstrate that hairy-cell leukemia may be associated with severe bone lesions similar to those observed in plasmocytoma. Moreover, these findings support the hypothesis that the hairy cell is a leukemic cell with B-lymphocyte properties.

Adult↗
PubMed1977

The activity and distribution of gamma-glutamyl transpeptidase (y-GT) in human foetal organs.

The activity and distribution of y-GT was investigated in a number of organs from human foetuses aged from 14 to 24 weeks post menstruationem. Over this period, enzyme activity increased in the kidney, pancreas and thymus, but decreased in the small intestine. No trend could be established for the liver, although activity was high. In the lung, spleen, brain and adrenals, y-GT was either detectable at very low levels or could not be demonstrated. The possible relationship between y-GT activity in some human tumours and the enzyme level in the corresponding foetal organs is discussed.

Female↗
PubMed1977

[Oncorna-like virus particles in the cochlear spiral ganglion of guinea pigs (author's transl)].

INTRODUCTION: Virus particles in spiral ganglion cells of the guinea pig have been grouped with herpes viruses. The purpose of this study was to evaluate this classification of the viruses and their influence on cell morphology. MATERIAL AND METHODS: 20 healthy, adult guinea pigs from different breeds were studied. The spiral ganglion was serially sectioned and examined electron micoscopically. RESULTS AND DISCUSSION: All examined spiral ganglions of several guinea pig populations from different breeds showed intracytoplasmic viruses in some granular spiral ganglion cells. According to their localization and morphology we classify these viruses with the oncorna virus group. This is not in agreement with the classification of other authors. Apparently there is a world-wide latent viral infection in guinea pigs. The accumulation of lysosomal-like vacuoles in vicinity to the viruses indicates an increased local lysosomal activity of the infected ganglion cells. Considering the otherwise normal ultrastructure of the infected cells an additional influence of these viruses on the intracellular metabolism can neither be demonstrated nor denied.

Animals↗
PubMed1977

Morphology, histochemistry and isozymes of monkey kidney cells during long-term exposure to cigarette smoke.

Monkey kidney cells (Vero) in monolayer culture were exposed to 260 puffs of whole smoke from a mid tar range cigarette over a period of 240 days. Cell morphology was investigated at the light and electron microscopic level. The histochemical characteristics of several hydrolytic enzymes and dehydrogenases were examined, and the isozymes of LDH, MDH and G6PD studied. For all these parameters smoke exposed cells displayed the same features as sham exposed and negative controls. The cells were assessed as non malignant by their failure to form tumours in the nude mouse.

Acid Phosphatase↗
PubMed1977

[Morphological virus diagnosis].

Morphological virus diagnosis is based on the detection of pathological changes in organs, tissues and cells at the macroscopic, lightmicroscopic and/or ultrastructural levels. Cytopathic effects may be caused directly by virus replication or be secondary in nature. A number of morphological methods with different degrees of specificity are available for the demonstration of virus particles and viral antigens. Examples are presented and the most important morphological characteristics of the viruses of the major groups are summarized.

Cytopathogenic Effect, Viral↗
PubMed1975

The assessment of tobacco smoke toxicity in organ culture. II. Ultrastructural studies on the immediate response of foetal rabbit tracheal epithelium to short-term exposures of whole smoke.

Foetal rabbit tracheal organ cultures were exposed under defined conditions to whole cigarette smoke and fixed immediately for electron microscopy. After an exposure to 4 or 8 puffs, epithelial intercellular spaces were enlarged, the apical portion of many cells bulged out into the lumen and many cilia were swollen. An exposure to 12 puffs produced a breakdown of the epithelium.

Animals↗
PubMed1975

Ultrastructural studies on cells of hamster lung cultures after chronic exposure to whole smoke or the gas vapour phase of cigarettes.

High levels of gas vapour phase constituents in cigarette smoke enhanced abnormal growth and tumorigenicity in primary cultures of hamster lung cells regularly exposed over long periods to the smoke from one of three types of cigarette. The ultrastructure of such cells was investigated by electron microscopy. Cells from cultures exposed to low levels of gas vapour phase constituents resembled cells from control, non-exposed cultures, and were filled with secondary lysosomes of the autophagic vacuole type. These autophagic vacuoles contained dense particles similar in size to the nucleoids of certain viruses. Cells from cultures exposed to high levels of gas vapour phase constituents and cells from tumours formed in nude mice after subcutaneous injection of transformed cultures lacked autophagic vacuoles but contained a higher number of cytoplasmic microfilaments. R-type (equals H-type) virus particles were found in the ER cisternae of control and exposure cultures at all ages, whilst A-type virus particles were found in close association with mitochondria in a transformed, exposed culture and in control cells which also formed tumours in nude mice but only after a much longer culture period.

Animals↗