Search PubMed⌕ Search

Biomedical subjects

P Fritsch

Publications and source records attributed to P Fritsch.

At least 163 records · Page 9Linked to original sources
PubMed1989

[Acquired, surface giant nevus cell nevi in generalized, atrophic, benign epidermolysis bullosa].

A 10-year old girl with generalized benign atrophic epidermolysis bullosa (EB) developed large nevomelanocytic nevi over a period of 1 year. Since such nevoid lesions have been repeatedly observed in other patients with generalized benign atrophic EB they should be regarded as a characteristic clinical feature of this type of mechanobullous disease. Regular observation of such patients will demonstrate the significance of these pigmented lesions as precursors of malignant melanoma.

Biopsy↗
PubMed1988

IFN-mediated induction of MHC antigen expression on human keratinocytes and its influence on in vitro alloimmune responses.

The MHC Ag expression on the surface of keratinocytes is altered after treatment with IFN. IFN-gamma induces, as expected, a strong increase in class I MHC Ag expression as well as de novo expression of class II MHC Ag, whereas IFN-alpha 2 only slightly increases class I MHC Ag and does not induce keratinocytes to express class II MHC Ag. We used untreated and IFN-pretreated keratinocytes as stimulators and also as targets to study whether IFN-induced MHC Ag changes would alter the immunogenicity of keratinocytes in alloimmune responses. It was found that class II MHC Ag-carrying keratinocytes were unable to induce the proliferation of resting lymphocytes, but did stimulate T blasts. Untreated keratinocytes were virtually resistant to the lysis by classical CTL but became susceptible after exposure to IFN-gamma, but not IFN-alpha 2 at physiologic doses. These data demonstrate mechanisms by which the release of IFN-gamma might contribute to the development of disease such as the graft vs host disease.

Cell Division↗
PubMed1988

Evolution of sister-chromatid exchanges (SCE) in rat bone marrow cells as a function of time after 2 Gy of whole-body neutron irradiation.

We scored sister-chromatid exchanges (SCE) in bone marrow cells in 3-month-old rats as a function of time after 2 Gy of whole-body neutron irradiation. This dose reduced the mean survival time to 445 days after irradiation, and induced more than one tumor per animal; by 200 days post irradiation, all animals bore tumors at autopsy, but bone marrow was not a significant target for tumor induction. In controls, the mean SCE/cell remained constant from 3 to 24 months of age (2.38 SCE/cell, S.D. = 0.21). Irradiation induced 2 distinct increases in SCE: the first occurred during the days following exposure, and the second, from days 150 to 240. Thereafter, SCE values formed a plateau at 3.37 SCE/cell (S.D. = 0.39) until day 650. Between the two increases (i.e. from days 15 to 150), SCE dropped to control values. Analysis of SCE distribution per cell shows that the entire dividing cell population altered homogeneously during the increase in SCE. These results suggest that in our irradiated rats, the second increase in SCE coincides with tumor growth, whereas the first increase might be due to DNA damage that was rapidly repaired.

Animals↗
PubMed1988

Ketoconazole 2% cream versus hydrocortisone 1% cream in the treatment of seborrheic dermatitis. A double-blind comparative study.

Seventy-two patients with seborrheic dermatitis were treated once daily with 2% ketoconazole cream (n = 36) or 1% hydrocortisone cream (n = 36) on a double-blind basis for 4 weeks. For the global evaluation, no significant difference could be seen between the two groups. The clinical response was 80.5% in the ketoconazole group and 94.4% in the hydrocortisone group. For the different symptoms combined (scaling, redness, itching, and papules), no significant difference was seen between the two groups when the total scores at week 2 and at week 4 were compared with the initial scores. The incidence of side effects in both groups was comparably low.

Administration, Cutaneous↗
PubMed1988

Localization of plutonium retention in the small intestine of the neonatal rat, guinea pig, baboon and macaca after Pu-citrate ingestion.

The retention of Pu-citrate in the gastrointestinal wall was compared at similar post ingestion times after ingestion at 2 days of age by rats and guinea pigs and at 1 to 34 days by neonatal primates. The small intestine was the main site of the Pu retention in all species. In rats and primates, most of the Pu was retained in the distal ileum, whereas in guinea pigs it was more homogeneously distributed. In the rats, Pu was retained in the epithelial cells on villi, but in the guinea pigs and primates it was confined to the macrophages under the epithelial cells in the lacteal region.

Animals↗
PubMed1988

Rejection, after a slightly prolonged survival time, of Langerhans cell-free allogeneic cultured epidermis used for wound coverage in humans.

Autologous cultured epidermis (CE) grown from small skin biopsies in vitro has been successfully applied for wound grafting in humans. Since it has been reported recently that allogeneic CE might be tolerated as permanent wound cover, we investigated the properties of CE and its use as autologous and allogeneic grafts. Except for some differences, such as the absence of Langerhans cells and the lack of a stratum corneum, CE resembled its natural analogue. Autologous CE applied for grafting of leg ulcers and various surgical skin defects adhered firmly and permanently to the wound bed within 2 weeks, became regularly stratified, and formed a stratum corneum. Langerhans cells gradually entered the grafts; the dermis contained no inflammatory infiltrate. Allogeneic CE unmatched for MHC and blood group antigens used to partially cover tangentially excised third-degree burns, donor sites of split-thickness skin, and a defect after tumor excision initially survived well like the autografts. However, they were completely rejected after 10-22 (mean, 14.5) days, which is 4-5 days later than reported for split-thickness skin allografts. Clinically, rejection presented as "melting" of the graft. (Immuno)histologically, we found a dense mononuclear dermal infiltrate consisting predominantly of activated T cells, vacuolization, and single-cell necrosis of keratinocytes, as well as HLA-DR expression on keratinocytes, and finally separation and lysis of the epidermis. Limiting dilution analysis in 2 out of 4 allograft recipients revealed a considerable increase of circulating donor-specific cytotoxic T cell precursors during graft rejection. We conclude that grafting of allogeneic CE does not lead to permanent but to slightly prolonged graft survival.

Adolescent↗
PubMed1988

Comparison of Western blot (immunoblot) based on recombinant-derived p41 with conventional tests for serodiagnosis of human immunodeficiency virus infections.

To evaluate the performance of a serological test for human immunodeficiency virus type 1 (HIV-1) infections based on the use of a recombinant envelope gene-derived protein as the antigen, we caused expression of a 1.4-kilobase fragment of HIV.DNA that codes for the complete gp41 transmembrane protein in an Escherichia coli expression vector and used Western blots (WB; immunoblots) prepared with recombinant material (pEX-41) to detect antibodies to HIV-1. This test detected all 339 sera which were positive by a combination of conventional serodiagnostic assays and produced no false-positive results with 311 negative samples. Also no false-positive results were obtained with 20 sera from systemic lupus erythematosus patients which had high titers of cross-reactive autoantibodies. In six cases, the pEX-41 WB proved to be more sensitive than individual assays applied on their own, and in five cases it was even more sensitive than a combination of conventional assays. We tested 221 sera in both our pEX-41 WB and a commercially available recombinant enzyme immunoassay (EIA [Abbott]). The results were identical in 188 cases. A total of 27 sera containing antibodies to gp41 as demonstrated in the pEX-41 WB, as well as the Abbott recombinant EIA, had no antibodies to the recombinant core antigen as measured in the Abbott EIA. However, 25 of these sera did stain the 24-kilodalton band on a WB with purified virus. Six sera that were positive in all of the conventional confirmatory assays and reacted strongly with the pEX-41 WB did not recognize the surface antigen used in the Abbott recombinant EIA. We conclude that the use of WB prepared with recombinant-derived p41 offers a very sensitive and specific method to detect antibodies to HIV.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Macular amelanotic melanoma in situ.

This report aims at directing the attention to the rare entity of amelanotic melanoma in situ, as exemplified in a patient who had an amelanotic lentigo maligna 10 years ago and a recurrent lesion of identical clinical and histological (except for pagetoid tumor cells in the epidermis) appearance 4 years ago. Amelanotic melanomas in situ appear as inconspicuous reddish macules, which can hardly be diagnosed or even suspected on clinical grounds.

Cheek↗
PubMed1988

[Amyloid K].

Electron-microscopic, histochemical and immunological studies have shown that the deposits of primary and secondary localized cutaneous amyloid (amyloid K) consist mainly of keratin filament material. The amyloid P component is the second most significant constituent. Pathogenetically, defective keratinocyte apoptosis is the most likely mechanism of generation for amyloid K. Apoptosis is a distinct mode of cell death according to which individual basal keratinocytes disintegrate in physiological and pathological conditions to form membrane-bound "apoptotic" bodies consisting mainly of keratin filament aggregates. These lose their protective membrane and drop into the upper dermis, where they present as keratin (Civatte, cytoid) bodies, which are regularly coated with immunoglobulins. Overproduction of keratin bodies and/or a defect in their degradation by enzymatic digestion or phagocytosis by macrophages and fibroblasts, followed by conversion into amyloid fibrils, may be responsible for the generation of deposits of amyloid K.

Amyloid↗
PubMed1988

Hemangiosarcoma in chronic leg ulcer.

We recently evaluated a patient with an angiosarcoma arising in a long-standing ulceration of his leg, which appeared representative of a characteristic, though fairly uncommon, subgroup of angiosarcomas. The clinical and immunohistochemical features of the tumor enabled us to define its origin from vascular endothelial cells.

Aged↗
PubMed1987

[Cultivated epidermis as a skin replacement--improved technics using mesh silastic sheets].

The cover of cutaneous wounds with cultured epidermis can be significantly improved by prior backing of the epithelium with meshed silastic sheets, whereas other materials, such as vaseline gauze, foam rubber etc., are not as satisfactory. Meshed silastic is affixed to the epithelium surface just before the enzymatic detachment from the culture flask is completed. Thus it protects the delicate epithelial membrane from injury during transplantation and helps to control its polar orientation. In addition, the silastic mesh prevents the graft, which initially does not possess any horny layer, from drying up and allows adequate drainage of wound secretions. Cultured epidermal grafts prepared by this method take very well (more than 90%) attaching to the wound bed quite firmly within a week.

Bandages↗
PubMed1987

Acute lesions induced by alpha-irradiation of intestine after plutonium gavage of neonatal rats.

After gavage of two-day-old rats with 238Pu(IV)-citrate at 17.4 MBq/kg (122 kBq per animal), 45 per cent of the animals died during the second week following ingestion. Histological analysis showed that death was due to acute intestinal lesions caused by alpha-radiation that resulted in denudation of the ileum. Under these experimental conditions, the total alpha-dose delivered to the ileal wall and its contents was estimated at 150 Gy. No acute lesions were observed after gavage of two-day-old rats with Pu-citrate at 5.3 MBq/kg.

Acute Disease↗
PubMed1987

Effects of the chemical forms and valency states of neptunium on its jejunal transfer in the rat.

The transfer of various Np(IV) and Np(V) chemical forms across the small intestine of rats was measured in instilled and perfused jejunum. Instillation of Np(V) nitrate together with citrate or DTPA resulted in the same absorption of Np as after instillation of Np(V) nitrate alone (3 per cent per hour). Perfusion of Np(V) nitrate with bicarbonate or DTPA resulted in a similar transfer (2 per cent) but added citrate or ascorbate resulted in reduced transfer (0.8 per cent). Addition of phytate reduced Np transfer in both instilled and perfused jejunum (0.4 per cent). Np(IV) transfer was usually the same as, or less than that of, the corresponding Np(V) forms. Np(IV) transfer was similar in perfused and instilled jejunum, increasing from 0.2 per cent in the presence of citrate and phytate, to 1 per cent with EDTA and DTPA. Except for phytate, all the forms of Np(V) tested behaved like Np(V) nitrate after transfer from the intestine or after intravenous injection. By contrast, the behaviour of Np(IV) varied for all the forms tested and, for a given form, varied as a function of the experimental procedure used, i.e. jejunal instillation, perfusion, or intravenous injection. These findings suggest that the intestinal transfer of Np might occur via the intercellular pathway, and that it is controlled by both the molecular weight of the Np compound and its stability constant.

Animals↗
PubMed1987

Phagocytosis of keratin filament aggregates following opsonization with IgG-anti-keratin filament autoantibodies.

IgG-anti-keratin intermediate filament autoantibodies occur in low titers in all normal human sera. These same antibodies are present in high titers in the sera of patients who have diseases in which cells containing keratin intermediate filaments (KIF) have been damaged, such as systemic lupus erythematosus, graft-versus-host disease, and cutaneous tumors. Since some human autoantibodies are thought to function in part as opsonins promoting the removal of insoluble cellular proteins after tissue injury, we investigated the influence of IgG-anti-KIF autoantibodies on the phagocytosis of insoluble KIF aggregates by human monocytes and polymorphonuclear neutrophils (PMN). Keratin intermediate filaments assembled in vitro were reconstituted into dense spherical KIF aggregates 0.3-2.5 microns in diameter by dialysis against phosphate-buffered saline. Immunoelectron microscopy revealed that, as expected, human IgG-anti-KIF autoantibodies bound to the KIF aggregates. Human monocytes or PMN were incubated either with nonopsonized KIF aggregates or with KIF aggregates that had been reacted with IgG-anti-KIF autoantibodies. The uptake of KIF aggregates was visualized by indirect immunofluorescence, immunoperoxidase staining, and immunoelectron microscopy. Monocytes rapidly and efficiently bound and phagocytosed KIF aggregates that had been coated with IgG-anti-KIF autoantibodies. Nonopsonized KIF aggregates, in contrast, were taken up much less efficiently. Differences were most marked at 4 degrees C for 60 min with phagocytosis of opsonized KIF aggregates by 23 +/- 8% of monocytes in contrast to phagocytosis by only 0.2 +/- 3% monocytes when nonopsonized KIF aggregates were used. Similar results occurred at 37 degrees C for 5 min with phagocytosis by 38 +/- 28% vs 1.8 +/- 0.4% of monocytes of opsonized and nonopsonized KIF aggregates, respectively. A high percentage of PMN also phagocytosed opsonized KIF aggregates, whereas nonopsonized KIF aggregates were ingested less avidly. These data indicate that the opsonization of extracellular KIF aggregates by IgG-anti-KIF autoantibodies plays an important role in promoting the phagocytosis of KIF aggregates. The subsequent phagocytosis represents a rapid and very effective mechanism for the removal of insoluble KIF following keratinocyte cell death.

Autoantibodies↗
PubMed1987

Progressive systemic sclerosis and nervous system involvement. A review of 14 cases.

Nervous system involvement in progressive systemic sclerosis (PSS) has been considered rare compared to other collagen diseases. We present 14 additional cases of PSS with neurological manifestations. Primary involvement of the peripheral nerves could be detected in 4 of 14 patients and is documented by electromyo- and electroneurographical examinations. Central nervous system (CNS) manifestations directly related to PSS are a rarity, which may reflect the lack of collagen in the brain, histological differences between cerebral and other arteries and the immunological particularity of the brain. There may have been a direct relationship between CNS involvement and PSS in only one patient presenting with an overlap-syndrome.

Aged↗