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Biomedical subjects

V Desmet

Publications and source records attributed to V Desmet.

At least 73 records · Page 4Linked to original sources
PubMed1990

Adhesions, focal sclerosis, protein crescents, and capsular lesions in membranous nephropathy.

All biopsies of membranous glomerulopathy collected between 1965 and 1988 (n = 198) were examined for the presence of adhesions, focal sclerosis, protein crescents, capsular drops, and other capsular lesions. These were observed with a frequency related to the number of glomeruli in the biopsy and the number of sections examined. A peculiar interrelation between these lesions was found. In the 63 cases with sufficient clinical follow-up, the capsular lesions were associated with a lower incidence of remission of the disease, and with more proteinuria and a higher serum creatinine at the last follow-up. It is hypothesized that focal detachment of podocytes may result in the formation of a protein crescent if a plasma-like filtrate is 'injected' between the epithelium of Bowman's capsule and its basement membrane. The detachment of the epithelium may lead to focal sclerosis and the formation of adhesions. The capsular drop is thought to be a final stage of inspissation of the protein crescent.

Adult↗
PubMed1990

Expression of MHC class II antigens and immunoglobulin M by the corneal epithelial cells in herpetic keratitis.

The corneal buttons obtained from 4 patients with active epithelial and stromal herpetic keratitis were studied with routine microscopy and immunohistochemistry. We used an immunoperoxidase technique with monoclonal antibodies directed against Langerhans cells, lymphocyte subsets, MHC products and immunoglobulins A, G, M and D. The epithelium and stroma contained an inflammatory infiltrate composed of polymorpho-nuclear leukocytes, dendritic cells, B-lymphocytes and T-lymphocytes (helper/inducer and suppressor/cytotoxic subsets). The epithelial cells of all the corneal buttons expressed MHC class II antigens. IgM was bound to the membrane of the epithelial cells in 3 specimens. HSV antigenic material was localized in the epithelial cells and in the stromal keratocytes by a direct immunofluorescence technique. Our data suggest that cell-mediated as well as antibody-mediated immune responses are involved, with a possible role for an autoimmune mechanism in the pathogenesis of this condition.

Adult↗
PubMed1990

Efficacy of interferon alfa-2b with or without prednisone withdrawal in the treatment of chronic viral hepatitis B. A prospective double-blind Belgian-Dutch study.

A prospective, double-blind study was carried out to assess the efficacy of interferon alfa-2b, with or without pre-treatment prednisone withdrawal, in patients with chronic hepatitis B. A total of 57 Belgian and Dutch patients were included in the study. Patients were divided into four treatment groups: Group A, prednisone withdrawal followed by interferon 5 million units per day; Groups B and C, placebo followed by interferon 5 or 1 million units, respectively; and Group D, untreated controls followed for 1 year. All treated patients received interferon for 16 weeks. Two of the 14 control patients lost hepatitis B e antigen during the year of study, and only one of 15 patients in the interferon 1 million units group. Among the 28 patients receiving 5 million units of interferon (with or without prednisone withdrawal), ten (36%) cleared hepatitis B e antigen during the study or within 6 months of the end of therapy. This was associated with a marked improvement in serum transaminase levels. When comparing Groups A and B, it was found that prednisone withdrawal therapy enhanced the response to interferon in patients with pre-treatment serum alanine aminotransferase levels below 100 IU/l, bringing the seroconversion rate up to 50%, compared to 17% on interferon alone. This effect was not seen in patients with high pre-treatment transaminase levels. All treatment responders showed a marked improvement in Knodell index score, whereas in the 15 non-responders from groups A and B, overall inflammatory activity remained the same in six, improved in five and worsened in four.(ABSTRACT TRUNCATED AT 250 WORDS)

Belgium↗
PubMed1990

Arsenic and non-cirrhotic portal hypertension. A report of eight cases.

It was discovered that eight patients with complications of non-cirrhotic portal hypertension had received an arsenical preparation for psoriasis as Fowler's solution some years age. Seven of them were admitted for bleeding oesophageal varices. Upon admission, splenomegaly and hypersplenism were present. Liver tests were normal and palmar skin keratosis and melanosis were noted. Liver biopsy of six patients showed features of incomplete septal cirrhosis. Malignant skin lesions were present in half of the patients. One patient died from lung carcinoma and another from an ovarium neoplasm. Chronic arsenic intake should be actively looked for in all patients with psoriasis and non-cirrhotic portal hypertension. They should be followed up for many years for development of malignant lesions in skin, lung and liver. Liver abnormalities present in the biopsies are often minor and may escape detection.

Adult↗
PubMed1989

Primary malignant fibrous histiocytoma of the esophagus.

A 59-year-old man was admitted to the hospital for dysphagia and fever. Esophagogram and upper gastrointestinal endoscopy revealed a polypoid mass in the midesophagus. Subtotal esophagectomy, cervical esophagogastrostomy, and lymph node dissection were performed. The histological diagnosis of the tumor was malignant fibrous histiocytoma. An area of severe epithelial dysplasia was found in the esophageal mucosa 3 cm under the tumor.

Esophageal Neoplasms↗
PubMed1989

Immunopathological study of vernal keratoconjunctivitis.

The in situ immune reaction occurring in the conjunctival tissues of patients with vernal keratoconjunctivitis was studied using immunohistochemical techniques and a panel of monoclonal and polyclonal antibodies. Our data point to a complex immunopathogenesis of the disease. The anaphylactic response was demonstrated by the presence of many eosinophils and mast cells showing membranous IgE staining in the epithelial and stromal inflammatory infiltrate. IgE+ plasma cells were rare or absent in the conjunctival tissues and around the acini of accessory lacrimal glands, suggesting that IgE is not produced locally in the conjunctival tissues. A humoral immune response was evidenced by the presence of small B-lymphoid follicles, scattered B-lymphocytes, and many plasma cells in the stromal inflammatory infiltrate. IgA+ and IgG+ plasma cells were of more or less equal numbers and outnumbered IgM+ plasma cells. The majority of plasma cells around the acini of accessory lacrimal glands were IgA+. A role played by cell-mediated immunity was evident from the presence of scattered stromal T-lymphocytes and many dendritic cells in the epithelium and stroma. Some stromal dendritic cells carried IgE on their surfaces.

Adolescent↗
PubMed1989

Immunopathology of trachomatous conjunctivitis.

Upper palpebral conjunctival biopsy specimens obtained from eight patients with active trachoma were examined by routine histological and immunohistochemical methods. The epithelium expressed class I major histocompatibility complex (MHC) products throughout and class II MHC products in the superficial layers. The epithelial inflammatory infiltrate consisted of polymorphonuclear leucocytes, macrophages, T lymphocytes, and dendritic cells. In the underlying stroma the inflammatory infiltrate was organised as B lymphoid follicles, and there was also a diffuse infiltrate consisting of plasma cells and scattered B lymphoid cells, dendritic cells, T cells, macrophages, and polymorphonuclear leucocytes. Each type of cell has its special location in the tissue. Plasma cells were located on a subepithelial band and as a dense infiltrate round the acini of accessory lacrimal glands. IgA+ plasma cells outnumbered IgG+ cells, whereas IgM+ and IgE+ cells were few. Our data provide good evidence for the presence of both humoral and cell mediated immune responses and a possible role for autoimmune mechanisms in the conjunctival tissues of trachoma patients.

Child↗
PubMed1989

Recombinant interferon-gamma induces HLA-DR expression on human corneal epithelial and endothelial cells in vitro: a preliminary report.

The effect of interferon-gamma on the expression in situ of major histocompatibility complex (MHC) products in human corneas was studied in vitro. Incubation for four days with 5 or 50 mg/l of Escherichia coli-derived recombinant human interferon-gamma resulted in the appearance de novo of MHC class II or HLA-DR antigens on variable numbers of corneal epithelial cells as well as on corneal endothelium, whereas it had no effect on the expression of MHC class I or HLA-ABC antigens. These results may help to explain the mechanism underlying the expression of HLA-DR antigens on corneal and limbal epithelium in various inflammatory eye diseases.

Cells, Cultured↗
PubMed1988

Phenotypic characterization of inflammatory cells in phlyctenular eye disease.

Phlyctenular conjunctival biopsy specimens obtained from seven patients presenting with ulcerated limbal phlyctens were examined with routine histology and immunohistochemistry using a panel of monoclonal and polyclonal antibodies and immunoperoxidase techniques. Large numbers of mononuclear phagocytes, dendritic Langerhans cells and polymorphonuclear leukocytes and moderate numbers of T-lymphocytes were observed in the epithelium. This infiltrate was most intense at the basal epithelial layers which expressed HLA-DR antigens. The underlying stromal inflammatory infiltrate was organized as perivascular cuffs and a scattered subepithelial infiltrate, and consisted of many mononuclear cells and poly-morphonuclear leukocytes. Among the mononuclear cells, monocyte derived cells dominated and included monocytes macrophages and dendritic cells. T-lymphocytes were present in moderate numbers, whereas B-lymphocytes and plasma cells, mostly of IgA class, were infrequent. These findings provided in situ immunohistochemical evidence that phlyctenular eye disease is the result of delayed type hypersensitivity immune response in which monocytes and monocyte derived cells play a central role.

Antibodies, Monoclonal↗
PubMed1988

Epidermal Langerhans cells, dermal dendritic cells, and keratinocytes in viral lesions of skin and mucous membranes: an immunohistochemical study.

We wanted to evaluate the eventual expression of viral antigens and MHC class II products by keratinocytes as well as the alterations of epidermal Langerhans cells and dermal dendritic cells in viral lesions of skin and mucous membranes. Therefore we investigated 68 biopsy specimens of protracted viral lesions, such as warts, condylomas, and mollusca contagiosa, and of rapidly resolving viral lesions such as herpes simplex virus infection. For this we used immunohistochemical staining techniques and several monoclonal and polyclonal antisera. In most cases investigated viral antigens (human papilloma virus antigens or herpes simplex virus type 1 antigens) could be demonstrated in keratinocytic nuclei. Except for a few viral lesions in which epidermal Langerhans cells were rather numerous, epidermal Langerhans cells were reduced in number or absent in almost all viral lesions. Moreover, epidermal Langerhans cells and dermal dendritic cells showed changes in morphology, distribution, and immunophenotype. These alterations may be caused by a toxic effect of the virus on dendritic cells. HLA-DR+ keratinocytes could be identified in few viral lesions only; HLA-DQ+ keratinocytes were not seen. Possible explanations for this lack of MHC class II expression by keratinocytes are discussed.

Antigens, Viral↗
PubMed1988

Drug-induced skin reactions and acute cutaneous graft-versus-host reaction: a comparative immunohistochemical study.

Skin biopsies from eight patients with drug-induced dermatitis have been compared with skin biopsies from 16 patients developing skin lesions (acute graft versus host-reaction and/or drug-induced reaction) after bone marrow transplantation. Biopsies were investigated using immunohistochemistry and several monoclonal antibodies. Morphological and immunohistochemical patterns in skin biopsies of both groups were very similar. The only difference seen was a reduced number of epidermal Langerhans cells with poorly developed dendrites in skin biopsies taken from patients who underwent bone marrow transplantation. If the latter finding is due to the cytotoxic drug regimen administered before bone marrow transplantation, as previously stated, we doubt the usefulness of skin biopsies in the differential diagnosis of acute graft-versus-host reaction and drug-induced skin lesions.

Adolescent↗
PubMed1988

Changes in small intestinal epithelial expression of MHC class II antigen after terminal ileal resection for Crohn's disease.

Aphthous lesions in the neoterminal ileum from patients operated for Crohn's disease are an early sign of recurrence that can be identified during ileocolonoscopy. The origin of these lesions was studied in nine patients treated by terminal ileal resection and right hemicolectomy for complicated Crohn's disease. During surgery the neoterminal ileum was turned inside out, the mucosa was carefully inspected and two large mucosal biopsies were obtained. The same procedure was carried out in seven patients operated for other diseases. Four to six months after surgery endoscopy of the neoterminal ileum was carried out and multiple biopsies were obtained from the neoterminal ileum. Another follow-up colonoscopy with biopsies was carried out one year after the operation. The operative specimens and the per- and postoperative biopsies were submitted to routine microscopy and immuno- and enzyme-histochemistry. None of the Crohn's patients had macroscopic lesions in the neoterminal ileum at operation and only one had microscopic signs of inflammation and a positive section margin. Four-six months after operation all Crohn's patients had active aphthous lesions in a 5-20 cm segment of the neoterminal ileum at endoscopy. Biopsies taken at this time showed microscopic features which were not observed in biopsies from control subjects: an increase of HLA-DR+, ATPase+ dendritic cells in the ileal mucosa and a defective expression of MHC class II antigens by the small intestinal epithelial cells. MHC class II expression by the small intestinal epithelial cells returned towards normal after one year.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphatases↗
PubMed1988

Intrahepatic bile duct development in the rat: a cytokeratin-immunohistochemical study.

The development of the intrahepatic bile ducts was studied in rats from day 12 of gestation until 10 days of age using three antibodies directed against cytokeratins in an immunohistochemical procedure on paraffin-embedded liver tissue. In adult rat liver, both hepatocytes and bile ducts were stained by the monoclonal anti-cytokeratin no. 8, whereas two polyclonal antibodies stained bile ducts only. Hepatocytes in developing rat liver were stained by monoclonal anti-cytokeratin no. 8 from day 12 of gestation on. On day 16, cells strongly immunoreactive for cytokeratin no. 8 were observed in a string of pearl-like arrangement around large vascular branches close to the liver hilum. Over the following days, similar structures appeared throughout the liver. Gradually, lumina were formed in these structures, again starting at the liver hilum and resulting in the formation of individual bile ducts. Immunoreactivity with the polyclonal antibodies was first detected in some of the string of pearl-like structures on day 19 and gradually increased until the intensity observed in adult rat liver was reached on day 1 after birth. Even on day 10, portal spaces still revealed more bile duct branches, rings of cells strongly positive for cytokeratin no. 8 and weakly positive with the polyclonal antibodies were present. It is concluded that the intrahepatic bile ducts develop from hepatocytes. The cells closest to large vascular spaces first become strongly positive for cytokeratin no. 8 and only later on acquire additional ("bile duct type") cytokeratins. This process starts at the liver hilum and spreads through the liver. Even at 10 days of age the bile duct system is still immature: around the smaller portal vein branches, rings of cells are still undergoing transformation into bile duct type cells. These data might be useful for reevaluation of pathologic phenomena.

Animals↗