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Biomedical subjects

C Hofmann

Publications and source records attributed to C Hofmann.

At least 145 records · Page 8Linked to original sources
PubMed1981

A new apparatus with high radiation energy between 320-460 nm: physical description and dermatological applications.

A new apparatus (UVASUN 5000) is presented with high radiation energy between 320-460 nm. The measurable energy below 320 nm was shown to be many orders of magnitude too low to produce erythema. The radiator is a specially developed source for high UV-A intensity, housing a quartz bulb with a mixture of argon, mercury and metal-halides. At a skin-target distance of 0.2 m the size of the irradiated area is 0.35 X 0.35 m, and the measured mean UV-A intensity is about 1400 W . m-2 (140 mW . cm-2). The UV-A energy in the range of 320-400 nm is about 84% of the total radiation energy. Effects of very high doses of UV-A on human skin were studied. Following single UV-A applications the minimal tanning dose UV-A (MTD) and the immediate pigment darkening (IPD) dose of UV-A were established. The calculated IPD threshold time was 1.8 min at 0.2 m. Repeated exposure to this UV-A delivering system yields long lasting dark brown skin pigmentation without any clinical or histological signs of "sunburn" (UV-B) damage, epidermal hyperplasia or thickening of the stratum corneum. The instrument was also successfully used for photo-patch testing and reproduction of skin lesions of polymorphous light eruption. Minimal therapeutic results were seen in the phototherapy of vitiligo and inflammatory acne.

Acne Vulgaris↗
PubMed1981

[Rosette forming B- and T-lymphocytes in allergic contact eczema (author's transl)].

The number of rosette forming lymphocytes with mouse and sheep red blood cells was examined in the time course of more localized (n = 16) and generalized (n = 12) allergic contact eczema. 1. In 25 healthy probands the mean number of B and T lymphocytes were 10 +/- 2.1% and 51 +/- 4.9%, respectively. 2. In generalized eczema a short significant increase of the number of both lymphocyte populations was observed. At the first day of examination 12 +/- 1.6% (p less than or equal to 1%) B and 59.1 +/- 5% (p less than or equal to 0.1%) T lymphocytes were counted. At the second day only the number of T lymphocytes (55 +/- 4.8%; p less than or equal to 5%) was increased, at the third day the number of T lymphocytes had normalized, too. 3. In the more localized eczema no changes in the number of lymphocytes could be found.

Animals↗
PubMed1980

Autoradiographic and planimetric analyses of the inflammatory infiltrate in psoriatic lesions under PUVA-therapy.

The effects of oral 8-methoxypsoralen-photochemotherapy (PUVA-therapy) on the inflammatory infiltrate in 14 psoriatic skin lesions and on normal skin of 7 controls were investigated by means of autoradiography and planimetry. Under PUVA-therapy, one finds a significant decrease in dermal cells per millimeter lesion in psoriasis. Percentage of 3H-TdR-labeled dermal cells in the lesions and total number of dermal cells in the control group do not change significantly. The relative decrease of dermal cells per millimeter lesion in psoriasis is far less significant than the reduction of 3H-TdR-labeled epidermal cells under PUVA-therapy.

Adult↗
PubMed1980

PUVA-treatment for solar urticaria and persistent light reaction.

A technique is described to successfully treat patients with extreme sensitivity to UV electromagnetic wave lengths with photochemotherapy. Representative data from a patient with solar urticaria and two patients with persistent light reaction are given. Prior to treatment the threshold doses for UV-C, UV-B, and UV-A were determined. Photochemotherapy was performed with standard 8-methoxypsoralen-UV-A (PUVA) schedules. Initial treatments were very difficult because of the extreme UV-sensitivity in all patients. Once pigmentation was induced, PUVA-treatments were easy to perform. All patients became almost free of symptoms and were able, for the first time in years, to resume normal outdoor activities. Remission was long-lasting. Photochemotherapy is offered as a new effective means to alleviate the symptoms of disabling photodermatoses.

Adult↗
PubMed1980

In vivo autoradiography and planimetry of epidermis in psoriatics under PUVA-therapy.

The effects of oral 8-methoxypsoralen-photochemotherapy (PUVA)-therapy) on involved epidermis of nine psoriatics and on normal skin of four control subjects was investigated by means of in vivo autoradiography and planimetry. Under PUVA-therapy there is a significant decrease of 3H-TdR labeled cells per epidermal cross-sectional surface, per length of basal membrane and per length of epidermal surface. There is also a significant decrease of epidermal thickness. In the initial phase of PUVA-therapy the decrease of 3H-TdR labeled cells is the most pronounced. The reduction of epidermal thickness is less than the decrease of 3H-TdR labeled cells.

Adult↗
PubMed1980

Cultured hepatoma cells as a model system for studying insulin processing and biologic responsiveness.

Monolayer cultures of minimal deviation hepatoma cells (H4-II-E-C3') bound and degraded insulin specifically, the apparent Ki value for insulin inhibition of both processes being 1 x 10(-8) M, indicating that cell-bound 125I-insulin is the substrate for subsequent hormone degradation in these cells as in isolated hepatocytes.1 The time course of insulin binding to its receptor depended on hormone concentration and temperature. Degradation of insulin also depended highly on temperature, with little or no degradation occurring at less than 20 degrees C, a temperature below which a membrane-lipid phase transition may block homone translocation or uptake. The effects of various agents on the binding and degradation of 125I-insulin also were tested. Agents believed to inhibit intralysosomal degradation of various proteins also inhibited the degradation of 125I-insulin by H4 cells (chloroquine, ammonium chloride, procaine, and lidocaine); inhibitors of energy production (dinitrophenol, sodium cyanide) inhibited degradation; an agent which inhibits microtubule function (vinblastine) blocked insulin degradation; and methylamine, reported to prevent receptor aggregation,2 also interfered with insulin processing. These findings are consistent with a model for cellular insulin processing, comprising receptor binding, clustering of receptors, endocytotic uptake, intralysosomal degradation, and extracellular release of some degradation products. H4 cells were highly sensitive to insulin. The KE for a half-maximal response of hormone-stimulated incorporationof 14C-glucose into glycogen was 10(-11) M insulin, corresponding to less than 1% receptor occupancy. This response was also mimicked by concanavalin A at a concentration of 10 microgram/ml. Vinblastine and chloroquine both significantly inhibited insulin-stimulated glucose incorporation into glycogen without affecting basal levels. However, since these inhibitory effects were not relieved by addition of excess insulin, it seems unlikely that their action on glycogen synthesis was exerted only at the level of the generation of an active intermediate or degradation product from hormone-receptor complexes. The hormone-sensitive H4 cells thus provide a useful system for further studies examining the role of insulin-receptor uptake in hormone action, receptor regulation, and signal termination.

Animals↗
PubMed1980

[Separation of lymphocytes by using visotrast 370 (author's transl)].

Enrichments of lymphocytes are mainly performed according to the flotation principle. By means of numerous differences with regard to the composition and density of the solution for separation, the relative acelleration and duration of the centrifugation the advantages and disadvantages of at least 7 methods were compared with our own modification: 1. Visotrast 370 diluted with Aqua dest. is equal to density gradients containing ficoll. 2. The one-step assays proved to be better and less time consuming than the combined methods. 3. With the density of the flotation medium of 1,076 g . cm-3 79 +/- 11% of the lymphocyte of the original blood were isolated, their purity was 93 +/- 3%, their vitality 91 +/- 4%. 4. There was slight contamination with other blood cells.

Acetrizoic Acid↗
PubMed1979

[Oral treatment with tretinoin: andrological, trichological, ophthalmological findings and effects on acne (author's transl)].

Twelve patients (20 +/- 2 years) with acne vulgaris were treated orally with 20-30 mg/day tretinoin (vitamin A acid) over 90-300 days. Various laboratory tests were performed to rule out unwanted pharmacological side effects. Tretinoin therapy was well tolerated except for minor complaints of dryness around the mucous membranes of mouth and nose. The acne remained unchanged. All laboratory tests were unremarkable except for a significant rise of ejaculate volume. Other sperm parameters, trichological, ophthalmological as well as blood and urine analyses showed no measurable effects of tretinoin therapy.

Acne Vulgaris↗
PubMed1979

[Semen analysis under photochemotherapy (PUVA-therapy) (author's transl)].

In 9 male patients with psoriasis vulgaris a semen analysis before and during photochemotherapy with 8-methoxypsoralen and UVA (PUVA) was performed to rule out drug-induced toxic damage of spermatogenesis or impairment of fertility due to scrotal hyperthermia. Two hours after oral application of 40--60 mg 8-methoxypsoralen the patients had been irradiated in UVA high intensity treatment units. PUVA-treatments were performed four times weekly until total body clearing was achieved. For complete remission 13--26 (mean 20.5) PUVA-treatments were necessary. Corresponding total UVA-doses were 35.3--191.0 (mean 83.2) Joule/cm2. The investigated parameters total motility, progressive motility, spermatozoa density, total spermatozoa count, spermatozoa morphology, and seminal plasma fructose remained unchanged. Only the volume of the ejaculate showed a small decrease during 3 months of therapy. From this pilot study there is no evidence that PUVA-therapy leads to an impairment of fertility in male patients within their reproductive age.

Humans↗
PubMed1979

[Pseudo tumours of the adrenals--errors in interpretation and their avoidance (author's transl)].

In 13 patients an adrenal tumor was suggested by non-invasive roentgenologic studies (scout films of the abdomen, intravenous urograms, tomograms). The lesions turned out to be misdiagnosed after patients had undergone arteriography. Variations of the spleen, superimpositions of the tail of the pancreas and fluid filled hollow viscus were found to be the reason for this adrenal 'pseudo-tumors'. The possibilities of diagnosing those 'lesions' without doing invasive studies are discussed.

Adrenal Gland Neoplasms↗
PubMed1979

8-MOP plasma levels in PUVA problem cases with psoriasis.

8-MOP plasma levels of psoriatic patients poorly responsive to PUVA treatment (PUVA problem cases) (N = 14) and of psoriatic patients with adequate response to photochemotherapy (N = 7) were measured for 8 h after oral ingestion of 0.6-0.8 mg/kg body weight, using a gas chromatographic method. We investigated whether there are any differences in the course of the plasma kinetics between the two groups. Problem patients showed significantly lower 8-MOP plasma levels than the control group. Furthermore, the 8-MOP plasma levels increased more rapidly in the control group than in these problem patients. Deviations in time of the maximum 8-MOP plasma levels from the expected 2 h peak could be observed in 50% of the problem cases compared to only 14% of the control patients. There is no correlation between the dose and the 8-MOP plasma level achieved in the two groups, i.e. higher doses do not result in high levels. In individual cases there is not always a correlation between the plasma maximum of 8-MOP at the time of UV-A irradiation and the response to treatment. Adjustment of the UV-A irradiation to coincide with the maximum plasma levels led to an improvement in therapeutic results for three problem patients.

Adult↗
PubMed1979

Bowenoid lesions, Bowen's disease and keratoacanthomas in long-term PUVA-treated patients.

Four patients are described, two with histologically proven multiple foci of bowenoid lesions, one patient with bowenoid lesions and Bowen's disease, and one patient with two keratoacanthomas, most of the lesions occurring in non sun-exposed but photochemically treated areas of the body. These patients had received long-term PUVA treatment for their psoriasis. Two patients had a history of arsenic intake. The possible relationship of these epidermal lesions to light treatment is discussed.

Adult↗
PubMed1979

Mode of uptake and degradation of 125I-labelled insulin by isolated hepatocytes and H4 hepatoma cells.

The effects of various agents on the binding and degradation of 125I-labelled insulin by isolated rat hepatocytes and cultured H4 hepatoma cells were studied. Various lysosomotropic agents, including chloroquine, ammonium chloride, and the topical anesthetics, lidocaine and procaine inhibited insulin degradation by H4 hepatoma cells but had little effect on the binding of the hormone. Similarly, tosyl-L-lysyl chloromethyl ketone selectively inhibited the degradation of 125I-labelled insulin by isolated hepatocytes, as did the sulfhydryl reagents, p-hydroxy- and p-chloromercuriphenyl sulfonic acid. Inhibitors of energy production, including sodium fluoride, sodium azide, and dinitrophenol, also selectively inhibited the degradation of insulin by hepatocytes, although cyanide had no effect under the conditions used. Lectins and antimicrotubular agents, which are known to affect the mobility of plasma membrane proteins or of intracytoplasmic vesicles, selectively inhibited insulin degradation by hepatocytes to varying degrees, whereas agents which inhibit the function of microfilaments had no effect. At temperatures below 20 degrees C, insulin degradation was negligible but rose rapidly between 20 and 37 degrees C, suggesting that a membrane-related step is rate limiting in the overall degradative process. These results are all consistent with a model of insulin uptake by target tissue involving pinocytosis of receptor-bound hormone followed by intralysosomal degradation.

Animals↗
PubMed1979

[Pityriasis lichenoides chronica--a new indication for PUVA therapy? (author's transl)].

2 patients with long-standing and wide-spread pityriasis lichenoides chronica were treated with orally administered 8-methyoxypsoralen and UVA irradiation (PUVA therapy). After 15--21 PUVA treatments the patients were completely cleared. 3 and 4 weeks after the initial PUVA treatment, phase recurrences occurred in both patients. In 1 patient the lesions appeared clinically and histologically as pityriasis lichenoides et varioliformis acuta.

Administration, Oral↗