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Biomedical subjects

S Obalek

Publications and source records attributed to S Obalek.

34 records · Page 2Linked to original sources
PubMed1984

Molecular cloning and characterization of the genomes of nine newly recognized human papillomavirus types associated with epidermodysplasia verruciformis.

The genomes of 11 human papillomaviruses (HPVs) found in benign lesions of eight patients suffering from epidermodysplasia verruciformis were cloned in Escherichia coli after insertion into plasmid pBR322. The study of the sensitivity of the cloned HPV DNAs to 14 restriction endonucleases permitted the construction of physical maps. DNA-DNA hybridization experiments, performed under stringent conditions, showed that these viruses represent nine new types, HPVs 14 (with subtypes a and b), 15, 17 (with subtypes a and b), 19, 20, 21, 22, 23, and 24. These HPVs were divided into three groups based on an absent or very weak cross-hybridization among the genomes of the viruses belonging to different groups.

Chromosome Mapping↗
PubMed1983

Oncogenic potential of human papillomaviruses epidermodysplasia verruciformis: a counterpart of Shope papilloma-carcinoma complex.

Epidermodysplasia verruciformis, a model of viral oncogenesis in humans, shows a remarkable similarity to Shope papilloma-carcinoma complex in rabbits. In humans and rabbits, both host, i.e. genetics and immunity, and environmental factors are decisive for neoplastic conversion of benign proliferative lesions. The virus seems to function as an initiation and promotor of carcinomatous transformation. In epidermodysplasia verruciformis, specific virus types are involved in malignant conversion, but a deeply depressed cell mediated immunity is responsible for infection with the potentially oncogenic viruses.

Animals↗
PubMed1981

Identification of papillomaviruses in butchers' warts.

We have studied the papillomaviruses found in the hand warts of 60 butchers, most of them from 2 distant slaughterhouses. Warts differing in morphology and location were studied separately. The viruses were identified by molecular hybridization, restriction enzyme analysis and immunofluorescence. Four known human papillomaviruses (HPV-1, HPV-2, HPV-3, HPV-4) were detected and one hitherto unknown papillomavirus was identified in 9 butchers. The DNA of the latter virus did not anneal with any of the RNAs complementary to either HPV-1 to HPV-5 or bovine papillomavirus type 1 (BPV-1) DNAs, and showed a Hind II + III restriction enzyme cleavage pattern distinct from those of known HPVs and BPVs. This virus showed distinct antigenic properties, as shown by immunofluorescence, using HPV-1, -2, -3, -5, and BPV-1 antisera. It may represent a new type of human papillomavirus (HPV-7) or a yet unidentified animal papillomavirus. In addition, 6 butchers were found to be infected with a papillomavirus, distinct from the known skin HPVs and from BPV-1, which could not be characterized by restriction enzyme analysis. Eleven butchers were found to be infected by 2 viruses. A characteristic histological pattern was found to be associated with the different papillomaviruses.

Bovine papillomavirus 1↗
PubMed1979

[New developments relating to papillomaviruses].

Molecular hybridization technique and immunofluorescence studies with use of specific immune sera against the purified virions isolated from various types of warts and wart-like lesions of epidermodysplasia verruciformis (EV) made it possible to detect four different types of human papilloma viruses (HPV). The recognition of the viruses is important because of the different morphology of the lesions induced and their various oncogenic potentials. HPV1 is mainly responsible for plantar warts, HPV2 for common (hand) warts, HPV3 has been found both in flat warts and in the variety of EV in which skin lesions are of flat wart type, the course is relatively more benign, and usually malignant transformation is not to be expected. HPV4 was up to now found exclusively in the cases of EV with prevalent red and red-brownish plaques and hyper- and depigmentations similar to those of pityriasis versicolor. In all cases of this variety of EV malignancies occured invariably. In patients with EV, as also in--to a lesser extent--longstanding flat and/or common warts cell mediated immunity was in general lowered, but humoral specific anti-HPV antibodies were usually present. HPV type seems to be of a decisive significance for potential oncogenesis, because in a vast majority of cases EV due to HPV3 no malignancies occured in spite of anergy, whereas malignant transformation has been found in all cases due to HPV4, even in a patient with still preserved, although lowered, CMI.

Adult↗
PubMed1978

Immunological studies in epidermodysplasia verruciformis.

Immunofluorescence and cell mediated immunity studies have been performed in 14 cases of epidermodysplasia verruciformis (EV), 3 of those abortive or regressing in members of the families of the patients with EV. Two different types of human papillomavirus (HPV)--HPV3 and HPV4--have been found in cases of EV. HPV3 was detected also in flat warts without features of EV. There was no cross-reactivity between these two viruses, neither with HPV1 responsible for plantar warts nor with HPV2 inducing common warts. There was a relationship between the type of HPV and the clinical picture of EV as well as the malignant transformation, namely HPV4 has been found to be more oncogenic. Cell mediated immunity (CMI) seems to be an important factor because it was depressed in a vast majority of active cases and preserved in regressing and abortive cases (in the members of the families of EV patients). However, low CMI has been found in EV cases infected with HPV3 and in persistent flat warts also due to HPV3, which did not undergo malignant transformation. In contrast, in a case of EV due to HPV4 a malignant transformation occured in spite of still preserved, although lowered CMI. Various human papillomaviruses seem to differ in their oncogenic potential. HPV1 responsible for plantar warts, and HPV2 for common warts have no evident oncogenic potential, HPV3 inducing both EV and flat warts has a low oncogenicity, whereas HPV4 inducing some cases of EV seems more oncogenic.

Adult↗
PubMed1977

Immunological studies in psoriasis. The quantitative evaluation of cell-mediated immunity in patients with psoriasis by experimental sensitization to 2,4-dinitrochlorobenzene.

Quantitative techniques of sensitization to 2,4-dinitrochlorobenzene (DNCB) was used to determine in psoriasis the intensity and frequency of allergic reactions to DNCB following primary challenge with 2,000 microgram allergen and secondary challenge with decreasing doses of DNCB. 56 patients with psoriasis and 23 healthy volunteers were examined. Frequency of positive reactions to DNCB was similar in both groups, since all normal controls were sensitized, whereas only 8 of 56 psoriasis cases failed to develop delayed hypersensitivity to DNCB. However, the intensity of acquired contact allergy was significantly diminished in psoriasis in comparison with controls. The patients with stationary skin lesions resembled the normal population in the intensity of reaction to DNCB. Decreased intensity of DNCB sensitization seemed to be related to the activity of the disease, but not correlated with the extent of the lesions. A relationship was found between reduced reactivity to DNCB and decrease in E rosette-forming lymphocytes. The data suggest that the impaired function of T lymphocytes in active psoriasis could be responsible for both, defective recognition of contact antigens, such as DNCB, and the alteration of secondary response to DNCB.

Dinitrochlorobenzene↗
PubMed1976

Cell-mediated immunity in epidermodysplasia verruciformis.

Investigations were performed in 6 cases of epidermodysplasia verruciformis and 2 healthy family members. Nonspecific cell-mediated immunity (CMI) was studied by measuring response to phytohemagglutinin (PHA) and concanavalin A (Con A), percentrages of E- and EAC-rosette-forming lymphocytes, bacterial skin tests, and allergic reactions to dinitrochloro-benzene (DNCB). Impairment of CMI was manifested by reduction in the percentage of E rosettes, and lowered response to PHA, and- to a lesser degree- to Con A. The immune response to DNCB sensitization was invariably negative. Impairment of CMI was greater in cases of long duration and with extensive lesions. The cases of similar duration and extent of lesions, which never showed tendency to tumor formation, were not different in CMI in comparison with cases with numerous tumors. Only in cases with very advanced tumors CMI was impaired parallel to the gravity of the patient's general condition.

Adolescent↗
PubMed1975

Lymphocyte transformation in mycosis fungoides.

Lymphocyte transformation tests with PHA were carried out in 26 patients with mycosis fungoides (MF) in different stages of the disease. In premycotic and infiltrative stages of MF there were no significant disturbances in the lymphocyte response to PHA. Inhibition of DNA synthesis and blastic transformation was observed only in the tumorous stage. The results are in favour of the nosological distinctiveness of mycosis fungoides within the lymphoma group.

Aged↗
PubMed1975

Immunological phenomena in harmless mice during experimental carcinogenesis induced with long-term topical application of 7, 12-dimethylbenzanthracene (DMBA).

To estimate the influence of topical treatment with DMBA and induced tumors on delayed hypersensitivity, the response of spleen lymphocytes to PHA in vitro and macrophage migration inhibition with PHA were studied in DMBA-treated hairless mice. DNA synthesis and blastic transformation of cultured lymphocytes decreased after 6-12 weeks of DMBA application. Lymphocyte response to PHA gradually diminished during the experiment, as compared with control animals. Since the malignant transformation of skin tumors was not observed before 16 weeks of DMBA carcinogenesis, it seems that derangements in cellular immunity preceded the malignant proliferation. The increase in spleen weight and the absence of PHA-induced inhibition of macrophage migration in hairless mice with malignant tumors may also be related to the influence of the tumor itself on the lymphatic system of experimental animals.

Animals↗
PubMedDate not supplied

Cutaneous warts.

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Humans↗