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Biomedical subjects

M Sibony

Publications and source records attributed to M Sibony.

At least 19 recordsLinked to original sources
PubMed2000

Organizing pneumonia related to common variable immunodeficiency. case report and literature review.

A 68-year-old woman suffering from common variable immunodeficiency (CVI) developed a typical picture of organizing pneumonia. Causative factors other than CVI were eliminated. Several antibiotic regimens failed to improve the patient's condition, while the clinical manifestations rapidly disappeared under steroid therapy, with complete radiological recovery, but relapsed after steroid withdrawal. Finally, organizing pneumonia was definitely demonstrated by pathological findings obtained by open lung biopsy. Interestingly, pathological examination exhibited two other well-known CVI-associated lesions, i.e. benign lymphoid hyperplasia and noncaseating granuloma. In view of reports in the literature, we speculate that these different histological patterns could have resulted in a spectrum of symptomatic CVI-associated pulmonary disorders that improved under steroid therapy.

Aged↗
PubMed1999

Neuropathic arthropathy: a forgotten diagnosis? Two recent cases involving the hip.

Two cases of neuropathic arthropathy of the hip are reported. One was the first manifestation of tabes dorsalis in a 74-year-old man, whereas the second occurred in a 47-year-old woman with a history of spina bifida and L2-L5 epidural lipoma. Radiographic joint destruction occurred within five and three months, respectively. The main clinical and radiological features of neuropathic arthropathy are reviewed, and diagnostic pitfalls are discussed. There are no specific laboratory tests or histologic findings. This now rare condition should be routinely considered in patients with severe joint destruction contrasting with minimal pain. The reasons for the decision to use trochanteric-iliac coaptation in one of our patients and a wait-and-see approach in the other are explained. The literature is reviewed. Ten cases treated by joint replacement have been reported. However, neither joint replacement nor arthrodesis seem capable of restoring satisfactory hip function.

Aged↗
PubMed1998

Angiotensin-converting enzyme and male fertility.

The angiotensin-converting enzyme (ACE; EC 3.4.15.1) gene (Ace) encodes both a somatic isozyme found in blood and several other tissues, including the epididymis, and a testis-specific isozyme (testis ACE) found only in developing spermatids and mature sperm. We recently used gene targeting to disrupt the gene coding for both ACE isozymes in mice and reported that male homozygous mutants mate normally but have reduced fertility; the mutant females are fertile. Here we explore the male fertility defect. We demonstrate that ACE is important for achieving in vivo fertilization and that sperm from mice lacking both ACE isozymes show defects in transport within the oviducts and in binding to zonae pellucidae. Males generated by gene targeting that lack somatic ACE but retain testis ACE are normally fertile, establishing that somatic ACE in males is not essential for their fertility. Furthermore, male and female mice lacking angiotensinogen have normal fertility, indicating that angiotensin I is not a necessary substrate for testis ACE. Males heterozygous for the mutation inactivating both ACE isozymes sire wild-type and heterozygous offspring at an indistinguishable frequency, indicating no selection against sperm carrying the mutation.

Animals↗
PubMed1998

A new model of endovascularly induced renal artery stenosis in normocholesterolemic versus hypercholesterolemic rabbits.

RATIONALE AND OBJECTIVES: The authors determine the feasibility of creating renal artery stenosis by overdilatation and deendothelialization and compare the model in normocholesterolemic versus hypercholesterolemic rabbits. METHODS: Thirty male New Zealand White rabbits were randomized into two groups: group A (n = 15) was fed a normal diet and group B (n = 15) was fed a cholesterol-rich diet 4 weeks before stenosis induction. An aortogram was performed, then the right renal artery was overdilated with an angioplasty balloon-catheter, and deendothelialized. After 6 weeks, groups A and B were compared by angiographic and pathologic study. RESULTS: Comparison of group A versus group B showed that 12 arteries (80%) versus 6 (40%) were angiographically stenotic (P < 0.05); 14 (93%) versus 12 (80%) contained neointima (NS), 12 (80%) versus 3 (20%) showed medial disorganization (P < 0.01), and 9 (60%) versus 2 (13%) presented adventitial fibrosis (P < 0.01). CONCLUSIONS: A new model of endovascularly induced renal artery stenosis has been developed in rabbits. Medial proliferation and adventitial fibrosis are more frequent in normocholesterolemic rabbits.

Angiography↗
PubMed1997

Adrenocorticotropin-producing pituitary carcinoma with liver metastasis.

We report here the extremely rare case of a twenty-eight year-old woman with a metastatic ACTH-secreting pituitary carcinoma. This is the thirteenth case to be described in the literature. Ten years ago Cushing's disease was diagnosed. After pituitary surgery, then bilateral adrenalectomy, a Nelson's syndrome appeared. The particularly extensive pituitary secondary development led to several pituitary surgical procedures, radiotherapy, and octreotide treatment. Eight years after Cushing's disease was diagnosed, liver tumors were discovered. Pathological examination and ACTH immunostaining demonstrated the secretory nature of these metastases. The lack of ectopic tumor, the LPH/ACTH equimolar ratio and a study of the plasma proopiomelanocortin derivatives by HPLC showed that the ACTH secretion originated in pituitary tissues (in situ and liver metastases). The processing of POMC seems thus to be normal in this kind of tumor and metastases. Intact POMC levels were very high, indicating an aggressive tumor, and ACTH/LPH production was paradoxically stimulated by octreotide. This case is also exceptional because of the slow development of the disease, which may be due to the complementary hepatic chemoembolization treatment.

Adrenocorticotropic Hormone↗
PubMed1996

Predictive score for the development of hepatocellular carcinoma and additional value of liver large cell dysplasia in Western patients with cirrhosis.

The aim of this study was to identify high-risk patients for hepatocellular carcinoma (HCC). Among 151 patients with histologically proven cirrhosis hospitalized from 1987 to 1990 and prospectively followed-up until June 1994, 31 developed HCC. We assessed the predictive value of 22 variables recorded at enrollment for HCC occurrence by the log rank test and the Cox proportional hazards model. Six clinical and biological variables summarized predictive information of HCC: age > or = 50 years (P = .01), male (P = .01), large esophageal varices (EV) (P = .03), prothrombin activity < 70% (P = .04), serum alpha-fetoprotein (AFP) > or = 15 ng/L (P = .06), and anti-hepatitis C virus antibodies (P = .08). A clinicobiological predictive score identified two groups of patients at low (n = 67; 3-year cumulative incidence, 0%) and high risk for HCC (n = 84; 3-year cumulative incidence, 24%). The predictive value of this score was confirmed using an independent population of 49 patients with cirrhosis. Furthermore, liver large-cell dysplasia (LCD) had an additional predictive value in high-risk patients (P = 10(-4), which thus helped to define a subgroup at very high risk for HCC (n = 12; 3-year cumulative incidence, 72%). In Western patients with cirrhosis, a limited number of usual variables can identify a group of patients at high risk for HCC. Among these patients, liver biopsy allows for the determination a subgroup of patients at very high risk for HCC requiring intensive screening or preventive measures.

Age Factors↗
PubMed1996

[Effect of microwave pretreatment on the detection of Epstein-Barr virus EBER RNA's using in situ hybridization].

We have tested the influence of microwave pretreatment of tissue sections on in situ hybridization applied to the detection of Epstein-Barr virus-encoded small RNAs (EBER). To this end, different protocols have been tested on slides of 4 lymph node lymphomas: microwave pretreatment, proteinase K pretreatment, microwave followed by proteinase K and no pretreatment. To compare the sensitivity of each technique, several dilutions of oligoprobes were used. Hybrids have been detected by immunohistochemistry. The analysis of the nuclear stainings obtained shows an enhancement of the sensitivity in protocols using microwaves.

Endopeptidase K↗
PubMed1995

Enhancement of mRNA in situ hybridization signal by microwave heating.

BACKGROUND: Optimization of in situ hybridization protocols is of real interest when trying to detect small amounts of mRNA or when using low concentrations of probes. To enhance the hybridization signal, we have developed a modification of an in situ hybridization (ISH) protocol with radiolabeled cRNA probes. The detailed protocol of ISH used for paraffin sections is also described. EXPERIMENTAL DESIGN: In microwave (MW) heating, the tissue sections are heated in a sodium citrate buffer (0.01 M, pH 6). The effects of the pretreatment with MW were studied on kidneys and adrenals of young rats and on human pathologic samples using [35S]-RNA probes complementary to the mRNAs of some components of the renin angiotensin system. RESULTS: The heating pretreatment with the MW permitted us to obtain an enhancement of the hybridization signal, especially when using low doses of radioactive probes. This enhancement could be evaluated to 60 to 120% by computer-assisted quantification of the signal. Furthermore, the histologic structures and the staining with toluidine blue were not impaired by the heating treatment. CONCLUSIONS: The enhancing effect of the hybridization signal obtained using MW allows shorter autoradiographic exposure times and/or the use of lower concentrations of radioactive probes for the detection of mRNA or the detection of mRNA expressed at the threshold of detection with usual protocols.

Adrenal Glands↗
PubMed1995

Expression of p53 protein related to the presence of human papillomavirus infection in precancer lesions of the larynx.

The aim of this study was to gain some insight into the relationship of human papillomavirus (HPV) infection to p53 expression and to some pathological parameters in precancerous lesions of the larynx. Formalin-fixed paraffin-embedded tissue sections containing human laryngeal precancerous lesions were screened for p53 protein by immunohistochemistry with the monoclonal antibody DO7 and for the presence of HPV infection by polymerase chain reaction with consensus primers directed against the E6 gene. The presence of p53 protein was detected in 31 of 57 specimens (54.4%) including 7 of 9 cases with mild dysplasia (78%), in 4 of 9 cases with moderate dysplasia (44%), and in 15 of 23 cases with severe dysplasia (65%). Of 16 samples with keratotic benign squamous metaplasia, 5 were also p53 positive (31%). Of 6 samples that were HPV positive, all were of type 16. Interestingly, 3 of the 6 HPV-positive samples were p53 negative. There was 1 HPV-positive case with strong p53 staining and 2 HPV-positive cases with minimal p53 staining. The 2 HPV-positive cases with minimal p53 staining had mild dysplasia. The HPV-positive case with strong p53 staining displayed severe dysplasia. Of 23 cases that were both HPV and p53 negative, 11 presented with keratosis and no dysplasia, 5 with moderate dysplasia, and 7 with severe dysplasia. Our data indicate that nuclear accumulation of p53 protein, presumably resulting from p53 gene mutation, may occur in HPV-infected epithelial tissues. On the other hand, there are many precancer lesions, some exhibiting moderate or severe dysplasia, that are both HPV negative and p53 unreactive, suggesting that alterations of genes other than the E6 oncogene and the p53 tumor suppressor gene play a role in early laryngeal carcinogenesis.

Adult↗
PubMed1994

Angiotensin-converting enzyme in murine testis: step-specific expression of the germinal isoform during spermiogenesis.

Angiotensin I-converting enzyme (ACE) is known primarily as an endothelial enzyme that plays a critical role in the regulation of blood pressure. Another, shorter isoform of ACE is abundantly expressed in the testes of sexually mature animals. Using antibodies for immunoperoxidase detection and [35S]-labeled riboprobes for in situ hybridization (ISH), we studied the temporal expression and cell distribution of this germinal isoform of ACE in the testis of normal mice and rats as well as of pubertal and sterile mice. In both murine species, specific testicular ACE mRNA and its gene product are present only after completion of meiosis. Through studying two murine species in which spermatogenesis and spermiogenesis have been accurately described, as well as immature and sterile animals, it could be shown that ACE mRNA and its corresponding protein are first synthesized during the cap phase (steps 4-7). The maximum expression occurred during the acrosome phase (steps 8-12). ACE mRNA is no longer detectable in spermatids beyond step 14, whereas its gene product is expressed until the end of spermatid maturation. Therefore, ACE is exclusively produced in haploid germ cells and belongs to the growing family of proteins whose expression during definite maturation steps of spermiogenesis appears to be correlated with the unique process of germ cell differentiation.

Amino Acid Sequence↗
PubMed1994

Tissue-specific expression of type 1 angiotensin II receptor subtypes. An in situ hybridization study.

The angiotensin II type 1 (AT1) receptor in murine species exists as two isoforms (AT1A and AT1B) encoded by two different genes. Both subtypes have a 9/10 homology in the coding sequence of their mRNA. We examined organs of adult rats (liver, pituitary gland, adrenal gland, kidney, heart, and lung) to study the differential expression of these two genes in target tissues for angiotensin II. AT1A and AT1B mRNAs were detected by in situ hybridization using specific riboprobes for the 3' noncoding region of the mRNAs that have the lowest homology (approximately 6/10). Only AT1A was expressed in the liver, heart, and lung, and only AT1B was expressed in the anterior pituitary, where most cells were positive. In the adrenal gland, AT1A mRNA was detected in the zona glomerulosa and medulla and AT1B in the glomerulosa. In the kidney, AT1A mRNA was the predominant isoform (mesangial and juxtaglomerular cells, proximal tubules, vasa recta, and interstitial cells), but AT1B was also detected in mesangial and juxtaglomerular cells and in the renal pelvis. The results of this in situ detection suggest a tissue-selective regulation of AT1A and AT1B mRNAs. This tissue specificity may constitute a prerequisite condition if the two angiotensin II receptor subtypes, which are pharmacologically similar, are to selectively modulate the various effects of angiotensin II in the different target tissues.

Adrenal Glands↗
PubMed1994

Gonadal and adrenal catheterization during adrenal suppression and gonadal stimulation in a patient with bilateral testicular tumors and congenital adrenal hyperplasia.

We report the case of a patient with bilateral testicular tumors and congenital adrenal hyperplasia due to 21-hydroxylase deficiency. Catheterization of the left testicular and adrenal veins was performed. The presence of 11 beta-hydroxylated steroids in the spermatic veins confirmed the presence of testicular tumor secondary to adrenal rest cells. After adrenal suppression by dexamethasone combined with gonadal stimulation with hCG, a dramatic decrease in androgens and adrenal steroids was observed in the peripheral blood. Compared to the periphery, 21-deoxycortisol and 11 beta-hydroxy-delta 4-androstenedione levels remained higher than that of 21-deoxycorticosterone in the gonadal vein, but not in the adrenal vein, which seems to indicate that the nature of this ectopic tissue is unusual and that its sensitivity to dexamethasone depends on the adrenocortical zones. No rise in estradiol or testosterone was obtained after hCG stimulation, suggesting that all of the testicular tissue was inactive or destroyed. This finding was confirmed by histological examination.

Adrenal Glands↗
PubMed1994

[Prevalence and characteristics of anti-tissue antibodies in chronic hepatitis caused by hepatitis C virus].

OBJECTIVES: The prevalence and significance of antiorganelle antibodies in the serum of patients with chronic hepatitis C is a subject of controversy. We studied prospectively these characteristics in patients with chronic hepatitis C. METHODS AND RESULTS: Among 156 patients (age: 55 +/- 14 years; 83 females), 30 (19%) had significant titers of antiorganelle antibodies: anti-nuclear antibodies in 18, anti-smooth muscle antibodies in 8 (no anti-actin or anti-vimentine subtypes), anti-LKM1 in 2, type 2 anti-mitochondrial antibodies in 2 patients. Anti-organelle antibodies were not detected in 126 patients. Patients with anti-organelle antibodies were significantly older but no difference was found between the two groups for sex ratio, serum amino-transferases or gammaglobulins, histopathological liver activity or prevalence of lymphocytic sialadenitis. The presence of anti-organelle antibodies was not related to HLA phenotype, especially B8 DR3, or DR4. Response to alpha interferon, estimated by serum aminotransferase levels after six months of treatment, was the same in both groups. CONCLUSIONS: These results suggest that serum anti-organelle antibodies are prevalent in during chronic hepatitis C but do not indicate a distinct autoimmune mechanism. Furthermore, the typing of anti-smooth muscle antibodies might help distinguish chronic hepatitis C from type 1 autoimmune chronic hepatitis.

Adult↗
PubMed1994

[Secondary sclerosing cholangitis and chemo-embolization with lipiodol].

Two cases of sclerosing cholangitis after oily arterial chemoembolization are reported. In one patient angiocholitis with liver abscesses, in the other patient gradual cholestasis were the main clinical features. In both cases, endoscopic retrograde cholangiogram showed a stricture of the common hepatic bile duct and, in one case, irregularities of intrahepatic biliary tree. Histologic examination of the liver in the two patients pointed out the involvement of small bile ducts and arteriolar endarteritis obliterans. Ischaemia is likely to be the main mechanism of these two cases of sclerosing cholangitis as well as in those described after FUDR intra-arterial chemotherapy. The prevalence of sclerosing cholangitis after arterial oily chemoembolization is probably underestimated because of a non specific clinical presentation and need to be precise by further study.

Carcinoma, Hepatocellular↗