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Biomedical subjects

J F Michiels

Publications and source records attributed to J F Michiels.

At least 37 records · Page 2Linked to original sources
PubMed2000

Ultrastructure of the polymorphonuclear leucocytes in human immunodeficiency virus infection.

The ultrastructure of polymorphonuclear leucocytes (PMNL) was studied in 16 patients infected with the human immunodeficiency virus (HIV). PMNL were isolated from HIV-infected patients with CD4+ lymphocytes counts > 200/mm3 (without signs of active infection) (n = 12) (group 1), or < 200/mm3 (n = 4) (group 2), and from 16 healthy volunteers (group 3). Immunoelectron microscopy staining using an anti-beta 2 integrin antibody (anti-CD18) was performed on PMNL from three individuals of group 2 and of three individuals of group 3, before and after incubation with N-formyl-methionyl-leucylphenylalanine (f-MLP). The radical oxygen intermediates (ROI) production of PMNL was investigated by luminol-mediated chemiluminescence. A number of ultrastructural abnormalities in PMNL were found in a higher proportion in HIV-infected patients. These were: (a) an increase in the size of the Golgi apparatus and in the number of mitochondria, and in the quantity of endoplasmic reticulum; (b) some dysplastic features including large cytoplamic vacuoles, whorl of myelin, and nuclear pockets; (c) an increase prevalence of multivesicular bodies compared with control PMNL; (d) some cylindrical confronting cisternae and tubuloreticular structures. After anti-CD18 staining, gold particles were seen on the plasma membrane and more rarely inside the cytoplasm of PMNL from each group but no decrease in this staining was noted in HIV PMNL. Incubation with f-MLP similarly increased the immunostaining of the PMNL in each group. In vitro ROI production was significantly depressed for HIV PMNL compared with control PMNL. Some ultrastructural abnormalities observed in this study could support the possibility that one of the mechanisms underlying the qualitative functional defects of PMNL from HIV-infected patients may be related to some cytopathic effect.

Acquired Immunodeficiency Syndrome↗
PubMed2000

[Solid and pseudopapillary tumor of the pancreas: immunohistochemical and ultrastructural study of 2 pediatric cases].

We report 2 cases of solid and pseudopapillary tumors of the pancreas occurring in female children. Lesions were made of uniform small cells arranged in solid areas associated with pseudopapillary and cystic patterns. Immunohistochemistry study was positive for neuron-specific enolase, alpha-1 anti-trypsin and vimentin. Ultrastructural study showed an abundant cytoplasm, rich in mitochondria, containing a lot of granules of variable sizes, often disintegrated, and some lipid droplets. The differential diagnosis of this lesion included endocrine tumor, pancreatoblastoma and acinar cell carcinoma. It is a rare tumor of the pancreas with a favorable prognosis after complete resection.

Adolescent↗
PubMed1999

Cloning of a calcium channel alpha1 subunit from the reef-building coral, Stylophora pistillata.

While the mechanisms of cellular Ca2+ entry associated with cell activation are well characterized, the pathway of continuous uptake of the large amount of Ca2+ needed in the biomineralization process remains largely unknown. Scleractinian corals are one of the major calcifying groups of organisms. Recent studies have suggested that a voltage-dependent Ca2+ channel is involved in the transepithelial transport of Ca2+ used for coral calcification. We report here the cloning and sequencing of a cDNA coding a coral alpha1 subunit Ca2+ channel. This channel is closely related to the L-type family found in vertebrates and invertebrates. Immunohistochemical analysis shows that this channel is present within the calicoblastic ectoderm, the site involved in calcium carbonate precipitation. These data and previous results provide molecular evidence that voltage-dependent Ca2+ channels are involved in calcification. Cnidarians are the most primitive organisms in which a Ca2+ channel has been cloned up to now; evolutionary perspectives on Ca2+ channel diversity are discussed.

Amino Acid Sequence↗
PubMed1999

Autopsy findings in the acquired immunodeficiency syndrome (AIDS). A report of 395 cases from the south of France.

Necropsy findings in 395 adult patients with the acquired immunodeficiency syndrome (AIDS) who died in Nice, France, between March 1983 and May 1996 were compared retrospectively with antemortem diagnoses, risk factors and number of positive T CD4 lymphocytes at the time of death. Special emphasis on bacterial infections was made in this study. Lesions observed from 1983 through 1989 and from 1990 through 1996 were compared. We assessed the role of organ lesions in the immediate cause of death. The organ system distribution of major opportunistic infections and neoplasms was similar throughout the years of the study. The most common diagnostic disease entities in all organ sites were cytomegalovirus infection, toxoplasmosis and candidiasis. Toxoplasmosis was more common in the intravenous drug abuser group. Bacterial infections were frequent and contributed to the mortality and morbidity of all risk factor groups. Kaposi' sarcoma continued to occur more frequently in the homosexual population. Cytomegalovirus infection remained one of the most common causes of death from 1983 to 1996. Mortality from fungal and bacterial infections, and mycobacteriosis increased in frequency during the course of this study whereas deaths from pneumocystosis declined. The death rate from malignant lymphoma and carcinoma increased after 1989. The clinical cause of death concurred with the pathological cause in 55% of the cases. Lung was the most frequent organ involved followed by the central nervous system the gastrointestinal tract and the heart.

AIDS-Related Opportunistic Infections↗
PubMed1999

The uroprotection of mesna on cyclophosphamide cystitis in rats. Its consequences on behaviour and brain activities.

We studied the uroprotective effect of mesna, at doses of 40-300 mg/kg/i.p., in single or fractioned injections, on the development of cyclophosphamide (CP, 100 mg/kg/i.p.) cystitis in rats. The study concerns the histological, behavioural and nervous aspects of the disease. The specific effects of mesna, when injected alone, have also been considered. The mesna itself does not have specific deleterious effects, except at a dose of 300 mg/kg which provokes a moderate vesical inflammation although without consequence on the animal's behaviour. Mesna offers good protection against CP cystitis for only certain posologies. The uroprotective effects of mesna reach maxima at doses of 40-100 mg/kg and for fractioned injections given over the entire time frame of the urinary toxic release. The uroprotective effects of other posologies are only partial. The nervous activities were studied through the expression of Fos protein. The repetitive intraperitoneal injection of mesna induced a spinal activity and a preferential contralateral activity of the trigemino/reticular areas of the brainstem spinal cord junction--an effect which was reduced in the presence of CP. The prevention of cystitis by mesna was accompanied only by a reduction in spinal Fos activity, the supraspinal activities remaining high and in strict relationship with the vagal afferent activity. In conclusion, the uroprotective effect of mesna, which requires appropriate posologies, has led to the confirmation of the spinal actions of the CP cystitis, probably via the pelvic nerve, but did not allow a clear distinction between the consequences of the systemic (vagal) and local (spinal, pelvic) actions of CP at supraspinal level.

Animals↗
PubMed1999

[Multifocal MALT lymphoma and acute cytomegalovirus gastritis revealing CD4 lymphopenia without HIV infection].

We report the case of a 63 year-old female who presented with a seven-year history of epigastric pain and a sudden overall deterioration. Gastroscopy demonstrated inflammatory aspect and ulceration in the antrum and fundus. Histology showed a lymphocytic infiltrate consistent with low grade mucosa-associated lymphoid tissue lymphoma and cytomegalovirus gastritis. There was no evidence of Helicobacter pylori infection. Other investigations demonstrated two pulmonary foci consistent with lymphomatous infiltration and a reduced CD4 + T-lymphocyte count (85/mm3). Other screening tests including HIV serology were negative. This case of idiopathic CD4 lymphopenia, in conjunction with the other rare cases in the literature, allows us to reevaluate this condition and its unusual clinical presentation with two opportunistic pathologies.

Acute Disease↗
PubMed1999

[Secretory carcinoma of the breast. Report of a case in a 9-year-old boy].

The authors report a child male case of secretory carcinoma of the breast, associated with a abnormal tumoral karyotype (monosomy 22). The diagnosis was made by histopathological examination. This breast carcinoma is characterized by an abundant intra and extracellulary secretory material, which present a reactivity with antimilk proteins antibodies and includes spherical dense bodies, identified by ultrastructural study. The prognosis is not bad, whatever the age of the patient, particularly for the children and young women, displaying an locoregional aggressivity. The signification of a monosomy 22 in secretory carcinoma is unknown.

Breast Neoplasms, Male↗
PubMed1999

[Inflammatory pseudotumor of the intrahepatic biliary tract].

Hepatic inflammatory pseudotumors are rare, presenting with a severe clinical pattern mimicking neoplasm. The diagnosis is almost always based on pathological examination showing inflammatory lesions with a polymorphous infiltrate and variable amounts of fibrous tissue. Development in the biliary tract is rare. We report the case of a 53-year-old patient who was referred for poor general condition and jaundice; the initial diagnosis was cholangiocarcinoma. Pathological examination of the surgical specimen showed a right intrahepatic biliary duct inflammatory pseudotumor. The patient developed recurrent jaundice three months after surgery due to a lesion of the left biliary ducts. Treatment with cortisone resulted in rapid improvement of jaundice.

Bile Ducts, Intrahepatic↗
PubMed1999

Structure of the supernumerary ring and giant rod chromosomes in adipose tissue tumors.

Supernumerary ring or giant rod marker chromosomes are a characteristic of well-differentiated liposarcomas (WDLPS) and atypical lipomas (ALP) and are often observed as the sole cytogenetic abnormality, but are rare in lipomas. Using a combination of different methods, we extensively investigated the structure and composition of rings and giant rods in a series of 17 WDLPS-ALP samples and three intra- or intermuscular lipomas (IMLP), revealing a unique combination of particular features strikingly related to these tumors. Although the rings and rods displayed in vitro and in vivo stability, the presence of alpha-satellites could not be detected on these supernumerary structures. Comparative genomic hybridization analysis, in combination with fluorescence in situ hybridization, identified the chromosomal regions contributing to the formation of these chromosomes: in WDLPS-ALP, all carried amplifications of 12q 14-15 and the MDM2 gene, with variable other noncontiguous regions. In the three IMLP, the rings consistently carried amplifications of 12q15-21 and 1q21, but increased copies of MDM2 were found in only one case. Other genes located more proximal in 12q14-15 were amplified in several WDLPS-ALP, but showed a normal copy number in IMLP. Furthermore, the immunohistochemical expression of the MDM2 protein was detected in most (12/14) WDLPS-ALP, in 1-30% of the cells, but never in IMLP. These supernumerary chromosomes represent a peculiar kind of amplification structure, midway between double minute chromosomes and homogeneously staining regions, but the mechanisms underlying the formation of these structures remain obscure.

Aged↗
PubMed1998

[Influence of HIV-related immunodeficiency on the histopathology of chronic hepatitis C].

OBJECTIVE: There is substantial evidence demonstrating the aggravating effect of human immunodeficiency virus (HIV) infection on the progression of chronic hepatitis C virus (HCV) infection. There is however, little data on the affect of certain factors which could affect liver pathology findings in patients with concomitant HIV infection such as the duration of HIV infection or T-cell subpopulation counts. We examined pathology findings in patients with concomitant HIV and HCV infections to determine the impact of immunodepression. PATIENTS AND METHODS: We reviewed liver pathology data collected in patients with concomitant HIV and HCV infections grouping patients according to severity of the liver pathology: group 1 = cirrhosis or active hepatitis; group 2 = minimally active hepatitis or histologically normal liver. Transparietal liver biopsies were obtained for the work-up of viral hepatitis or because of long-term unexplained fever or suspected lymphoma. Epidemiological and biological data were obtained from medical files. The duration of the liver disease was estimated from the date of exposure to risk of immunodepression as determined by the peripheral CD4+ and CD8+ counts. All pathology specimens were read by two pathologists who established the Knodell score for each patient. RESULTS: Fifty patients were included: 23 were classed in group 1 and 28 in group 2. The Knodell score was significantly different between the two groups, 11 +/- 4 and 4 +/- 3 respectively (p < 0.0001). Disease duration was similar for the two groups: mean 8 years. Mean CD4+ count was significantly higher in group 1: 312/mm3 versus 110/mm3 for group 2 (p = 0.0057); as was the mean CD8+ count (758/mm3 versus 360/mm3, p = 0.0013). For the entire study population, there was a significantly negative correlation (p < 0.05) between the Knodell score and the CD4+ count (r = 0.31) and for the CD8+ count (r = 0.41). CONCLUSION: HCV-related liver pathology in patients co-infected with HIV depends on the level of immunodepression. CD8+ counts are better correlated with pathology findings than with CD4+ counts.

Adult↗
PubMed1998

Cyclophosphamide cystitis as a model of visceral pain in rats: a c-fos and Krox-24 study at telencephalic levels, with a note on pituitary adenylate cyclase activating polypeptide (PACAP).

This article is the fifth of a series aimed at mapping brain activities as they result from the development of cyclophosphamide (CP) cystitis in behaving rats using c-fos and Krox-24 expression. The inactive hepatic metabolites of CP are metabolized in the kidney to produce acrolein, which generates cystitis. Data come from animals which were injected once i.p. with either 1 ml saline (sham) or 100 mg/kg CP in 1 ml saline under transient volatile anesthesia and which behaved freely for 1-4 h postinjection, 4 h being the minimum time for cystitis to completely develop. Survival times longer than 4 h were not studied owing to ethical considerations. The first 2 h postinjection cover a period of time over which inputs of multifactorial origin (stress and pain due to the intraperitoneal injection process, possible effects due to the presence of hepatic CP metabolites in blood, cystitis onset) interact in an indistinguishable way; the last 2 h are more cystitis specific as the other effects have vanished. Complete screening of telencephalic levels has been performed. These data complete previously published data at both spinal and subtelencephalic levels. Of all the telencephalic structures, only the bed nucleus of the stria terminalis in the dorsal part of its lateral division (BSTLd) and, to a lesser degree, the nucleus centralis of the amygdala, mostly in its caudal portion (cCeA), appeared to be significantly driven over the most specific cystitis period. Both of these structures had related, but not identical patterns of expression. They both reacted shortly after CP injection, but, while cCeA maintained its activity throughout cystitis development, BSTLd showed a rebound, reaching a peak value when cystitis was fully developed. Both of these areas are the only telencephalic areas to contain high PACAP38 immunoreactivity. This is evidence that, (1) both the BSTLd and cCeA could be the most rostral areas that visceronociceptive inflow would reach when cystitis genesis is under way, and (2) PACAP38 could be one of the neurochemical agents involved in telencephalic visceronociceptive processing. From our complete mapping of brain activities under a fully developed cystitis situation (4 h postinjection), it appears that the activities in BSTLd and cCeA are concomitant with those of both the dorsal vagal complex (DVC), paratrigeminal nucleus (PaT), and the ventrocaudal bulbar reticular formation (vcBRF) at brainstem levels, suggesting they all form the main part of the neural network that subserves the central processing of cystitis-related inputs, comprising pain and associated pseudoaffective responses. Both the DVC and BSTLd, which are the most powerfully driven areas, would be particularly important in such a way. The origin of these activities should be found in both vagal (as sensed through PaT activity) and spinal (pelvic) influences. This network profoundly differs from those reported for painful situations, either somatic or visceral, which controversally accompany positive cardiac inotropism.

Animals↗
PubMed1998

Endodermal cyst of the foramen magnum: case report and review of the literature.

The majority of endodermal cysts occur in the cervicothoracic spine, ventral to the cord. Intracranial locations are rare. We report a case involving the foramen magnum in a 14-year-old child, which was an incidental finding following a traumatic head injury. A review of the literature revealed six other cases involving this same location. These lesions are asymptomatic for a long time, and may cause brain stem medullary compression. Treatment is surgical. Effective simple removal can be achieved by a posterior approach.

Adolescent↗
PubMed1998

Albendazole for treatment and prophylaxis of microsporidiosis due to Encephalitozoon intestinalis in patients with AIDS: a randomized double-blind controlled trial.

A double-blind placebo-controlled trial was conducted to assess the efficacy and safety of albendazole (400 mg twice daily for 3 weeks) for the treatment of Encephalitozoon intestinalis infection in patients with AIDS. Clearance of microsporidia from the intestinal tract was obtained in 4 of 4 patients in the albendazole group versus 0 of 4 in the control group (P = .01, one-sided Fisher's exact test) and was associated with significant clinical benefit. All 4 controls subsequently cleared microsporidia following open-labeled albendazole treatment. To investigate the effect of albendazole in preventing relapse, these 8 patients were then randomly assigned to receive either albendazole (400 mg twice daily) or no treatment for the next 12 months. Albendazole significantly delayed the occurrence of relapse (P = .04, one-sided log-rank test). In human immunodeficiency virus-infected patients with E. intestinalis infection, albendazole has parasitologic and clinical efficacy and reduces the risk of relapse.

AIDS-Related Opportunistic Infections↗
PubMed1998

[Placental infection in Rwanda: comparison an HIV infected population and a control population].

We report an histological study from term placentas of 286 HIV positive women born in Rwanda. We observed chorioamnionitis without any pathogen in 15% of the cases, cocci Gram positive infection in 12 observations and malaria infection in 75% of placentas. We noted 71 cases of active malaria infection with Plasmodium falciparum trophozoites in the erythrocytes of the intervillous spaces, and 135 cases of chronic infection with malaria pigment without any parasite. An ultrastructural study performed in 8 cases of active malaria infection showed characteristic features of trophozoites and schizontes, and malaria pigment. No viral particle were seen. We did not observe any significative difference concerning the incidence of chorioamnionitis and of malaria infection in 275 HIV negative placentas. In the literature as well as in the present study, the main lesions observed in the placentas of AIDS patients were chorioamnionitis. Opportunistic infections and neoplasias of the placenta are exceptional. Detection of HIV proteins by immunochemistry or in situ hybridization is possible, but the HIV could not be identified in the trophoblast by electron microscopy. Mechanisms of the materno-fetal transmission for HIV are currently unknown.

Acquired Immunodeficiency Syndrome↗
PubMed1998

[Kimura's disease of the lymph node. Histology, immunohistochemistry, and differential diagnosis].

Kimura's disease, a chronic inflammatory condition of unknown cause, occurs predominantly in young Asian adult men. The disease involves subcutaneous tissues and lymph nodes in the head and neck region. We report a new case occurring in a young woman. The diagnosis was made late on a retroauricular lymph node examination. Immunohistochemical study showed that B lymphoid area remained, located in the germinal center showing some fibrosis involvement, and in the subcortex. T lymphoid zones were observed in the paracortex. Strong IgE positivity was noted in germinal centers. Vessels were positive with CD31, CD34, factor VIII and smooth muscle actin antibodies. Warthin-Finkeldey cells were negative for lymphoid and macrophagic markers used in this study. Differential diagnosis is discussed.

Actins↗