Proliferation and migration of granule cells in the developing rat cerebellum: cisplatin effects

We evaluated the relationship among proliferation, death and migration of granule cells in lobules VI-VIII of vermis, in comparison with lobule III, during cerebellar development. To this aim, a single injection of cisplatin, i.e., a cytostatic agent that is known to induce death of proliferating granule cells, was given to 10-day-old rats. Histochemical markers of proliferating (PCNA immunoreaction) and apoptotic (TUNEL staining) cells were used; the variations of the external granular layer (EGL) thickness were evaluated in parallel. After PCNA and TUNEL reactions, evident changes of the whole EGL were found on PD11 (1 day after treatment), when a reduction of the thickness of this layer was found in treated rats, mainly in consequence of the high number of apoptotic cells in all the cerebellar lobules. On PD17 (7 days after treatment), a thick layer of proliferating cells was observed in lobules VI-VIII of treated rats, while the peculiar pattern of the normal development showed a thin EGL. At the same time, in treated rats, the number of apoptotic cells in EGL was low. In all developmental stages of treated rats, after GFAP immunoreaction, glial fibers appeared twisted, thickened, and with an irregular course; intensely labeled end-feet were present. The damage of radial glia suggests an alteration of migratory processes of granule cells, which is also evidenced by the decreased thickness of the premigratory zone of the EGL. Injured radial glia fibers were restricted to lobules VI-VIII and they persisted at PD30, leading to the presence of ectopic granule cells in the molecular layer, as we previously described.     

Primary and secondary elastin-binding protein defect leads to impaired elastogenesis in fibroblasts from GM1-gangliosidosis patients

G(M1)-gangliosidosis is a lysosomal storage disorder caused by acid beta-galactosidase deficiency. Aside from the lysosomal beta-galactosidase enzyme, the beta-galactosidase gene also encodes the elastin-binding protein (EBP), deficiency in which impairs elastogenesis. Using expression studies and Western blots of COS-1 cells, we identified and characterized four new and two known beta-galactosidase gene mutations detected in G(M1)-gangliosidosis patients with infantile, juvenile, or adult forms of disease. We then focused on impaired elastogenesis detected in fibroblasts from patients with infantile and juvenile disease. The juvenile patient showed connective-tissue abnormalities, unusual urinary keratan sulfate excretion, and an EBP reduction, despite mutations affecting only beta-galactosidase. Because galactosugar-bearing moieties may alter EBP function and impair elastogenesis, we assessed infantile and juvenile patients for the source of altered elastogenesis. We confirmed that the infantile patient's impaired elastogenesis arose from a primary EBP defect, according to molecular analysis. We examined the juvenile's fibroblasts by immunohistochemistry, addition of keratanase, soluble/insoluble elastin assay, and radiolabeling of tropoelastin. These experiments revealed that the juvenile's impaired elastogenesis likely arose from secondary EBP deficiency caused by keratan sulfate accumulation. Thus, impaired elastogenesis in G(M1)-gangliosidosis can arise from primary or secondary EBP defects in fibroblasts from infantile and juvenile patients, respectively.     

TNF-alpha induces surface modifications in mouse Sertoli cells: physiopathological implications

The expression of the adhesion molecules ICAM-1 and VCAM-1 has been measured in mouse Sertoli cells cultured in vitro. Cytometric analysis revealed that, in basal conditions, low levels of ICAM-1 and VCAM-1 were present on the surface of the cells, whereas treatment with TNF-alpha induced an increase in their expression. Binding experiments using both 51Cr-labelled lymphocytes, for quantitative analysis, and scanning electron microscopy demonstrated that increased expression of ICAM-1 and VCAM-1 on the surface of Sertoli cells, induced by TNF-alpha, determines an augmented adhesion between the two cell types. These results suggest the presence of a specific mechanism of interaction between Sertoli and immune-competent cells, possibly involved in the control of the immune response in the testis following an inflammatory reaction in situ. Such mechanism is of interest for the understanding of auto-immune pathologies of the testis and, if confirmed in humans, it could be involved in the sexual transmission of HIV infection.     

Presence of membrane and soluble forms of Fas ligand and of matrilysin (MMP-7) activity in normal and abnormal human semen

BACKGROUND: The aim of this study is to shed some light on the role of the Fas system in human semen, by investigating whether there is an association between the expression of the molecules regulating the Fas system [membrane-bound Fas ligand (mFasL), soluble Fas ligand (sFasL) and matrilysin, the metalloprotease cleaving mFasL to sFasL] and sperm parameters. METHODS: We investigated, by flow cytometric analysis, the presence of FasL on spermatozoa from normozoospermic and teratozoospermic subjects and, by western blot, the presence of sFasL and matrilysin in the seminal plasma of the same samples as well as on samples from azoospermic subjects. The enzymatic activity of matrilysin was examined by gel zymography. RESULTS: We observed that sperm cells expressed mFasL in 22% of normozoospermic men, whereas it was absent from spermatozoa from teratozoospermic patients. Higher levels of sFasL and augmented enzymatic activity of matrilysin were found in azoospermic samples. CONCLUSIONS: The presence of mFasL on sperm from normozoospermic men and its absence in pathological samples emphasize the role of the Fas system in human semen. Moreover, the presence of both sFasL and matrilysin in seminal plasma implies a fine regulation of the function of the Fas system and, consequently, of the apoptotic process in the human genital tract.     

Meier‐Gorlin syndrome (ear–patella–short stature syndrome) in an Italian patient: Clinical evaluation and analysis of possible candidate genes

Florescence in situ hybridization (FISH) using subtelomeric probes has been useful in detecting cryptic telomeric chromosomal rearrangements. We report, for the first time, that cytogenetically visible chromosome rearrangements can occur between the subtelomeric and telomeric region in clinically normal individuals with balanced chromosome anomalies in which one of the breakpoints involves a terminal band region. Using FISH with subtelomeric probes, we observed in three cases with a balanced reciprocal translocations the retention and subsequent loss of subtelomeric regions. In one case with a paracentric inversion, there was a proximal relocation of a subtelomeric region. Because subtelomeric regions serve important roles in chromosome pairing, this retention and concomitant loss or relocation of a subtelomeric region could possibly further disrupt the complex meiotic configurations of these balanced chromosome rearrangements. This may then have an effect on gamete production, placing these individuals at a higher risk for miscarriages and/or abnormal outcomes for individuals with similar chromosome aberrations. © 2002 Wiley‐Liss, Inc.     

Sleep‐disordered breathing in children with pycnodysostosis

Upper airway obstruction is a common feature in pycnodysostosis and may cause obstructive sleep apnea (OSA). The aim of our study was to analyze sleep‐disordered breathing and respiratory management in children with pycnodysostosis. A retrospective review of the clinical charts and sleep studies of 10 consecutive children (three girls and seven boys) with pycnodysostosis seen over a time period of 10 years was performed. Six patients had severe OSA and/or nocturnal hypoventilation and were started on continuous positive airway pressure (CPAP) as a first treatment at a median age of 3.4 ± 2.6 years, because of the lack of indication of any surgical treatment. Three patients could be weaned after several years from CPAP after spontaneous improvement (two patients) or multiple upper airway surgeries (one patient). Three patients had upper airway surgery prior to their first sleep study with two patients still needing CPAP during their follow‐up. Only one patient never developed OSA. Patients with pycnodysostosis are at a high risk of severe OSA, underlying the importance of a systematic screening for sleep‐disordered breathing. Multidisciplinary care is mandatory because of the multilevel airway obstruction. CPAP is very effective and well accepted for treating OSA.     

Autoreactive T cell specificity in autoimmune hemolytic anemia of the NZB mouse

Splenic T cells from Coombs'-positive New Zealand Black (NZB) mice proliferated consistently in vitro in response to the integral red blood cell (RBC) membrane protein Band 3, the antigen previously shown to be the target for the pathogenic RBC autoantibodies. The responding cells predominantly express CD4 and the proliferative response is blocked by antibodies to the NZB major histocompatibility complex class II but not by antibodies to an irrelevant H-2 haplotype. NZB splenic T cells also proliferated in response to the internal membrane skeleton protein spectrin. By contrast, T cells from BALB/c and DBA2 mice, which bear the same H-2 haplotype as NZB mice, but which do not develop autoimmune hemolytic anemia (AIHA), fail to respond to Band 3. It is considered that these results support the hypothesis that Band 3-reactive T cells provide help for the production of pathogenic anti-Band 3 autoantibodies in NZB mice. T cells from Coombs'-negative NZB mice as young as 3 weeks old proliferated in response to Band 3; moreover, the RBC from Coombs'-negative mice bore elevated levels of autoantibody as judged by a sensitive direct enzyme-linked anti-globulin test. Thus, the pathology of AIHA develops at a much earlier age than was thought previously.