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Biomedical subjects

I Fayt

Publications and source records attributed to I Fayt.

30 records · Page 2Linked to original sources
PubMed1999

Pre-Kaposi's sarcoma: an expansion of the spectrum of Kaposi's sarcoma lesions.

We report on a lymphoedematous form of classic Kaposi's sarcoma (KS) in which characteristic purplish lesions were surrounded by atypical oedematous, flesh-coloured papules. Histological examination of these papular lesions revealed a proliferation of grouped, rather thick-walled capillaries with inflammatory infiltrates. Hot-start PCR amplification with KS 330-233 primer sequences demonstrated the presence of human herpesvirus 8 (HHV-8) sequences. In addition, cells isolated from these oedematous papules showed morphological and immunohistochemical features similar to those reported for KS-derived spindle cells. As a whole, these results suggest that these oedematous papular lesions represent pre-KS lesions and may expand the clinico-pathological spectrum of KS. The role of oedema in their induction is discussed.

Aged↗
PubMed1998

Chronic rejection of major histocompatibility complex class II-disparate skin grafts after anti-CD3 therapy: a model of antibody-independent transplant vasculopathy.

BACKGROUND: Chronic rejection remains a leading cause of allograft loss. Histologically, it is characterized by arterial intimal thickening and parenchymal fibrosis. The immune mechanisms triggering chronic rejection are still uncompletely understood. METHODS: We performed major histocompatibility complex (MHC) class H-incompatible skin grafts from C-H2bm12 (bm12, H2bm12) into C57BL/6 (C57BL/6, H2b) recipients immunosuppressed with a short course of anti-CD3 monoclonal antibodies to prevent acute rejection. RESULTS: More than 80% of grafts survived for prolonged periods, but eventually all displayed macroscopic and microscopic evidence of chronic rejection. At histology, there was a progressive arterial intimal thickening as well as intense dermal fibrosis. This was accompanied by an inflammatory infiltrate consisting of lymphocytes and macrophages, but also of a considerable number of eosinophils. Mice with chronic rejection were unable to generate anti-donor MHC class II cytotoxic T lymphocyte activity at either 20 or 60 days after transplant. Furthermore, transplantation of bm12 skins on C57BL/6-congenic, Ig knock-out mice was associated with the development of a chronic rejection that was identical to that occurring in wild-type C57BL/6 animals, indicating that alloantibodies are not necessary in this model. CONCLUSIONS: (1) Skin grafts may undergo chronic rejection with the characteristic lesions of vasculopathy and fibrosis; (2) chronic rejection of MHC class II-disparate skins may occur in the absence of direct cytotoxic T lymphocyte activity or alloantibodies.

Animals↗
PubMed1998

PCR assay fails to detect molluscum contagiosum virus-related sequences in AIDS-related Kaposi's sarcoma.

Previous PCR-based studies have demonstrated the presence of various viral DNA or RNA sequences in Kaposi's sarcoma (KS) tissues. To date, only human herpesvirus 8 (HHV-8) DNA sequences are found consistently in KS. The putative role of this agent in KS pathogenesis remains, however, to be determined; HHV-8 could infect populations endemically and could be reactivated in patients with KS. A close association between AIDS-related KS and molluscum contagiosum occurrence was found and this study was conducted primarily to search for the presence of molluscum contagiosum virus DNA sequences in KS. Frozen KS samples were examined for the presence of both HHV-8 and molluscum contagiosum virus DNA sequences by PCR. Despite a high rate of co-infection, no molluscum contagiosum virus (MCV) DNA sequence could be found in the KS samples whereas HHV-8 was uniformly detected. These results suggest that the high prevalence of MCV in AIDS patients with KS relies on a mode of transmission common for HHV-8 and molluscum contagiosum virus rather than on a multiviral etiology of KS. They may also indicate a particular susceptibility of the host to viral reactivation. If this is so, the failure to detect MCV DNA sequences in KS tissues by PCR indicates that locally produced or released cyotokines are not involved in the latter process.

AIDS-Related Opportunistic Infections↗
PubMed1998

Detection and identification of human papilloma viral DNA, types 16, 18, and 33, by a combination of polymerase chain reaction and a colorimetric solid phase capture hybridisation assay.

A colorimetric microplate hybridization assay was developed previously to simplify detection procedures of DNA fragments resulting from polymerase chain reactions (PCR). This format has now been adapted for the simultaneous detection and identification of three human papillomavirus (HPV), types 16, 18 and 33, associated frequently with cervical cancer. This post-PCR detection system uses three type-specific capture oligonucleotides linked covalently to a single microplate well and three type-specific multibiotinylated oligonucleotidic probes for detection. It therefore offers a double specificity; the first is conferred by pairs of primers, specific of each type of virus tested, and the second, by the sets of capture and detection probes which are complementary to internal regions of the amplified DNA fragments. The detection format outperformed agarose gel electrophoresis of amplified DNA products in sensitivity and specificity. The rapidity and simplicity of this hybridisation system would justify its use in routine diagnostic examination of cervical specimens (smears and biopsies).

Colorimetry↗
PubMed1996

Herpesvirus-like DNA sequences and Kaposi's sarcoma: relationship with epidemiology, clinical spectrum, and histologic features.

BACKGROUND: The evidence of an infectious agent other than human immunodeficiency virus (HIV) acting as a possible etiologic cause of Kaposi's sarcoma (KS) has received considerable attention in the last years. Recently, DNA sequences from a new herpesvirus (HHV-8) have been observed in several cases of KS. The discovery suggests that this virus may play a role in the pathogenesis of KS. To evaluate these results, we determined the frequency of HHV-8 DNA sequences in 78 specimens of KS according to different epidemiologic origins (sporadic KS: 6, immunosuppressive drug-associated: 11, and AIDS-associated: 61), clinical forms (cutaneous: 69, mucocutaneous: 4 and visceral; 5) and histologic variants (early-patch: 40, late-plaque or nodular: 38). METHODS: We used the hot start polymerase chain reaction amplification method with KS330 primers specific for HHV-8 DNA. Tumoral or nontumoral skins and visceral specimens free of KS, originating from patients with KS positive for HHV-8 DNA sequences or from immunosuppressed patients without KS, served as controls. Normal skin from healthy HIV seronegative patients was also included. RESULTS: HHV-8 DNA sequences were found in 3 of the 6 sporadic KS (50%), in 5 of the 11 immunosuppressive drug-associated KS (45%), in 41 of the 61 AIDS-associated KS (67%), in 32 of the 69 cutaneous KS (46%), in 3 of the 4 mucocutaneous KS (75%) in 2 of the 5 systemic KS (40%), in 23 of the 40 early or patchstage KS (58%), in 30 of the 38 late plaque or nodular stages KS (79%). These sequences were also demonstrated in one sample of skin with scabies and in a glomerulonephritis lesion from two immunosuppressed patients with KS who were also positive for herpesvirus-like in their KS lesions. None of the other skin or visceral specimens, originating from healthy, AIDS, or transplanted patients without KS, were positive. CONCLUSIONS: Our results reinforce the hypothesis that HHV-8 is incriminated in different epidemiologic, clinical and histologic stages of KS and could contribute to the pathogenesis of this tumor. However, the presence of HHV-8 DNA sequences in skin and visceral samples free of KS from KS indicates that the virus is not restricted to the tumor tissue, and thus is able to disseminate in many organs of the target individual. Absence of the virus from healthy, AIDS, or transplanted patients without KS suggests that the viral Sequences either do not spread easily or do not easily maintain themselves in the human population.

Acquired Immunodeficiency Syndrome↗
PubMed1996

p53 Protein overexpression in verrucous carcinoma of the skin.

BACKGROUND: Verrucous carcinoma is a rare variant of well-differentiated squamous cell carcinoma which is characterized by a marked local aggressivity and a poor metastatic potential. Until now, little has been known about the oncogenic mechanisms of this tumor. Recently, extensive investigations have shown that p53 protein, a nuclear protein with oncogene-suppressing activity, may play a crucial role in cell transformation and immunoreactivity for this protein is found in a wide variety of cancers. OBJECTIVE AND METHODS: The aim of the present study is to examine the frequency of immunohistochemically detectable p53 protein by using two monoclonal antibodies (D07 and BP53-12) in 8 cases of formalin-fixed and paraffin-embedded specimens of verrucous skin carcinoma. RESULTS: Overexpression of p53 protein was detected in 6 (75%) of the cases examined with the D07 antibody and in 5 (62.5%) cases with BP53-12. The p53 positivity was shown in a peripheral distribution affecting mainly the basal cell layers of tumoral islands. CONCLUSION: In a high percentage of verrucous carcinoma, p53 immunoreactivity has not been previously described in the literature and our findings suggest that abnormal expression of p53 tumor suppressor protein is a common event in the pathogenesis of this tumor.

Aged↗
PubMed1995

Proliferating cell nuclear antigen distribution in verrucous carcinoma of the skin.

Verrucous carcinoma (VC) of the skin is a rare variety of well-differentiated squamous cell carcinoma (SCC) characterized by aggressive local growth and a low metastatic potential. These tumours are known to have histological and virological features similar to classic warts or condylomata. The aim of the present study was to map the proliferative compartment in VC (n = 7) in comparison with warts (n = 10) and typical well-differentiated SCC (n = 10). The proliferating cells were detected by immunostaining of proliferating cell nuclear antigen (PCNA) in formalin-fixed, paraffin-embedded tissue sections, using the commercially available anti-PCNA monoclonal antibody PC10. Normal epidermis served as a positive control and reference. In VC and warts, the PCNA-positive cells were principally located at the periphery of lesions, in the basal layer of the tumour islands. In some warts, however, stronger PCNA expressed was noted in the superficial layers, of the lesions corresponding to virus-infected keratinocytes (koilocytotic cells). In contrast, in SCC, PCNA-positive cells were randomly scattered throughout the tumours. Our findings suggest that, on the basis of mapping of PCNA distribution, VC resembles large warts or condylomata rather than typical SCC. Thus, VC appears to be a distinct clinical entity, intermediate between these two types of lesions, not only because of its clinical entity, intermediate between these two types of lesions, not only because of its clinical and virological features, but also with regard to its proliferative organization.

Carcinoma, Squamous Cell↗
PubMed1988

Osteoarticular amyloidosis associated with haemodialysis: an immunoultrastructural study.

Osteoarticular amyloidosis occurred in a patient receiving long term haemodialysis. Histological examination showed that the amyloid deposit was surrounded by inflammatory cells and macrophages filled with haemosiderin. Electron microscopy showed that the amyloid fibrils were in close contact with cytoplasmic expansions, or located in intracytoplasmic pockets of the infiltrating cells. Immunohistological and immunoultrastructural observations confirmed that beta 2-microglobulin was a major constituent of amyloidosis associated with dialysis. Amyloid P component was also detected within the amyloid deposits. These findings suggest that amyloid P component, iron overload, or macrophage derived factors could have a role in the polymerisation of beta 2-microglobulin into amyloid deposit.

Amyloid↗
PubMedDate not supplied

Evaluation of the role of human papillomavirus in oesophageal squamous cell carcinoma in Belgium.

OBJECTIVE: To evaluate the putative role of human papillomavirus (HPV) in the aetiology of oesophageal squamous cell carcinoma (OSCC) in Belgium. METHODS: The frequency of HPV infection was determined using HPV DNA PCRamplification with L1 consensus primers MY09-MY11, able to recognise about 40 different HPV types, on twenty-one formalin-fixed and paraffin-embedded oesophageal squamous cells carcinomas. Nineteen samples of histologically normal epithelium from the surgical margins of the OSCC specimens and five samples from normal oesophagus obtained at autopsy served as negative controls. RESULTS: We found only one HPV positive tumour (4.8%) out of the 21 OSCC cases. All the normal epithelium controls remained negative. CONCLUSIONS: Our data are in agreement with those previously published, suggesting that HPV infection only plays a minor role in the pathogenesis of oesophageal squamous cells carcinoma in West-European countries.

Adult↗