Mice deficient in the X-linked lymphoproliferative disease gene sap exhibit increased susceptibility to murine gammaherpesvirus-68 and hypo-gammaglobulinemia

X-linked lymphoproliferative disease is characterized by immune dysregulation and uncontrolled lymphoproliferation on exposure to Epstein-Barr virus (EBV). This disease has been attributed to mutations in the SAP gene (also denominated as SH2D1A or DSHP). To delineate the role of SAP in the pathophysiology of X-linked lymphoproliferative disease, a strain of sap-deficient mice has been generated by deleting exon 2 of the gene. After infection with murine gammaherpesvirus-68, which is homologous to EBV, the mutant mice exhibit more vigorous CD8+ T cell proliferation and more disseminated lymphocyte infiltration compared to their wild-type littermates. Chronic tissue damage and hemophagocytosis were evident in sap-deficient mice but not in their wild-type littermates. Concordantly, murine gammaherpesvirus-68 reactivation was observed in sap-deficient mice, indicating an impaired control of the virus. Notably, IgE deficiency and decreased serum IgG level were observed in mutant mice prior to and after murine gammaherpesvirus-68 infection, which reproduces hypo-gammaglobulinemia in X-linked lymphoproliferative disease patients. This mouse model will therefore be a useful tool for dissecting the various phenotypes of X-linked lymphoproliferative disease.

Enantioselective syntheses and cytotoxicity of N,O-nucleosides

Enantiomers of 4'-aza-2',3'-dideoxynucleosides have been prepared by two different synthetic approaches, on the basis of 1,3-dipolar cycloaddition of a chiral nitrone. Cytotoxicity and apoptotic activity have been investigated. (5'S)-5-Fluoro-1-isoxazolidin-5-yl-1H-pyrimidine-2,4-dione [(-)-AdFU], while showing low level of cytotoxicity, is a good inductor of apoptosis on lymphoid and monocytoid cells, acting as a strong potentiator of Fas-induced cell death.

Problems related to counseling in genetic thrombophilias

Venous Thrombosis is a major cause of mortality and morbidity in Western populations and in 30% of cases is associated to genetic susceptibility. Ideally, the identification of carriers of such susceptibility, known as thrombophilia, may allow for predicting the likelihood of recurrence in symptomatic patients and the risk of thrombosis in their relatives, leading to tailored plans of therapy and prophylaxis. In practice, this is greatly complicated by the high heterogeneity of both genotype and phenotype of inherited thrombophilia and by the lack of evidence-based guidelines for managing carriers. These issues and their impact on the process of genetic counseling for individuals suspected to have an inherited thrombophilia are discussed.

Rescue of human RET gene expression by sodium butyrate: a novel powerful tool for molecular studies in Hirschsprung disease

BACKGROUND

The RET gene encodes a tyrosine kinase receptor involved in different human neurocristopathies, such as specific neuroendocrine tumours and Hirschsprung disease (HSCR). Gene expression is developmentally regulated and the RET transcript is undetectable in most adult cells, including lymphocytes. The impossibility of performing functional studies on RET mRNA has to date limited the detection and characterisation of an indefinite proportion of gene anomalies that cannot be identified by conventional DNA genomic screening in HSCR cases.

AIMS

Development of a protocol suitable to activate RET expression in RET negative cell lines and therefore to investigate directly RET mRNA, extending the conventional gene mutation analysis to detection of splicing anomalies and impaired expression of the RET gene.

METHODS

The effect of sodium butyrate (NaB), a histone deacetylase inhibitor, on rescuing RET expression was tested by one round of reverse transcription- polymerase chain reaction from total RNA of treated lymphoblasts from both HSCR patients and control individuals.

RESULTS

Analysis of RET expression was possible by NaB treatment of RET negative cells, such as lymphoblasts. This treatment allowed us to detect impaired RET expression as well as a splicing defect in two HSCR patients previously believed to be devoid of any gene abnormality.

CONCLUSIONS

The full application of the proposed protocol in most of the unexplained HSCR cases will allow us to establish the precise role of RET not only in causing but also in predisposing to HSCR pathogenesis.

The Ret proto-oncogene in the WAG/Rij rat strain: an animal model for inherited C-cell carcinoma?

WAG/Rij rat strain has been suggested as an animal model for the study of inherited human medullary thyroid carcinoma (MTC), due to its high incidence of spontaneous C-cell thyroid tumours. Although the role of the Ret proto-oncogene mutations, as responsible for human MTC, is well established, nothing has been published concerning this putative animal model. Based upon the previously reported rat Ret sequence, exons 10, 11, 13, 14, 15, and 16, known to carry activating mutations in humans, have been analysed in the WAG/Rij rat by PCR, single strand conformational polymorphism (SSCP) and direct sequencing. Neither the germline nor MTC samples showed any Ret sequence difference in the exons when analysed in comparison to a non-MTC-susceptible rat strain. Our results indicate that Ret exons relevant in humans are not involved in WAG/Rij rat MTC, as expected, and this questions the validity of this strain as a model for the human disease, and suggests there must be additional mechanisms for the genesis and progression of rat MTC.

New rearrangement of 4-isoxazoline system: conversion of ketones into alpha,beta-unsaturated amides

A new rearrangement pattern of the 4-isoxazoline system is reported. The reaction, starting from 3,3-disubstituted derivatives and leading to alpha,beta-unsaturated amides, proceeds through the quaternarization of the nitrogen atom and involves the heterolytic cleavage of C(3)-N bond, assisted by the formation of a relatively stable intermediate. The overall process represents a useful conversion of ketones into alpha,beta-unsaturated amides.

Absence of SLAM mutations in EBV-associated lymphoproliferative disease patients

X-linked lymphoproliferative disease is a rare inherited immunodeficiency in which affected males present abnormal responses to Epstein-Barr virus (EBV) infection. The gene defective in X-linked lymphoproliferative disease, SH2D1A (also named SAP or DSHP), has been identified and shown to code for an adapter protein that interacts with signaling lymphocytic activation molecule (SLAM) and several other members of the CD2 superfamily. SH2D1A is mutated in no more than 60% of X-linked lymphoproliferative disease patients. It could be postulated that a certain percentage of patients without apparent maternal transmission might be caused by other gene(s) in SH2D1A-related signal transduction pathways. Being a partner of SH2D1A and having a key role in proliferation and differentiation of the T- and B-lymphocytes, SLAM was considered as a candidate gene for patients who manifest symptoms of X-linked lymphoproliferative disease but who have no mutations in SH2D1A. As a first step, SLAM mutations were screened for from cDNA of the lymphoblastoid cell line of all available patients. Then conditions for PCR, single-strand conformational polymorphism (SSCP), heteroduplex analysis, and sequencing were established in all eight exons of SLAM. A total of 31 typical and atypical patients were analysed, from which six novel nucleotide variants were identified; however, none of these variants seems to cause abnormal function of the SLAM gene. Therefore, mutations in coding regions or splicing sites of SLAM are unlikely to play a major role in the mechanism of EBV-associated lymphoproliferation.

Bilateral neonatal adrenal abscess. Report of two cases and review of the literature

Neonatal adrenal abscess is an extremely rare condition. 32 cases, 4 bilateral, have been described in the world literature. We treated successfully other two bilateral cases. We report on this rare condition and review the world literature. In our Department we observed two patients in the neonatal period with abdominal distension, vomiting, irritability and fever. Abdominal ultrasound (US), plain x-ray of the abdomen, intravenous pyelography and computed tomography (CT) of the abdomen were performed. In both cases bilateral suprarenal cystic masses were identified. Vanilmandelic acid, Homovanillic acid and cathecolamines were normal. The two neonates underwent a surgical exploration. Abscesses were found and drained releasing a moderate amount of haemorrhagic and purulent materials from the adrenal glands. Post-operative histology on the surgical specimen showed in both cases an abscess in partial haemorrhagic adrenal glands. No neoplastic cells were observed. The recovery was uneventful and at six months follow-up both patients were well and without signs of adrenal insufficiency. Haematogenous bacteria seeding a normal gland or abscess formation in a previous haemorrhagic gland are the most accredited theories. Neuroblastoma, Wilm's tumor and renal duplication with dilatation of the upper segment must be considered in the differential diagnosis. Percutaneous drainage (+/- biopsy) under CT or US guide should be considered the treatment of choice, followed by surgical exploration when diagnosis is not clear.

The netrin-1 receptors UNC5H are putative tumor suppressors controlling cell death commitment

The three mammalian receptors UNC5H1, UNC5H2, and UNC5H3 (also named UNC5A, UNC5B, and UNC5C in human) that belong to the family of the netrin-1 receptors, UNC5H, were initially proposed as mediators of the chemorepulsive effect of netrin-1 on specific axons. However, they were also recently shown to act as dependence receptors. Such receptors induce apoptosis when unbound to their ligand. We show here that the expression of the human UNC5A, UNC5B, or UNC5C is down-regulated in multiple cancers including colorectal, breast, ovary, uterus, stomach, lung, or kidney cancers. In colorectal tumors, this down-regulation is associated with loss of heterozygosity occurring within UNC5A, UNC5B, and UNC5C genes but may also be partially related to epigenetic processes because histone deacetylase inhibitor increased UNC5C expression in various cancer cell lines. Moreover, sequencing of UNC5C gene in patients with colorectal tumors revealed the presence of missense mutations. The lossreduction of expression may be a crucial mechanism for tumorigenicity because the expression of UNC5H1, UNC5H2, or UNC5H3 inhibits tumor cell anchorage-independent growth and invasion. Moreover, these hallmarks of malignant transformation can be restored by netrin-1 addition or apoptosis inhibition. Hence, UNC5H1, UNC5H2, and UNC5H3 receptors may represent tumor suppressors that inhibit tumor extension outside the region of netrin-1 availability by inducing apoptosis.

Variations in lectin-binding on the zona pellucida during oocyte growth in some wild ungulates

The aim of the present study was to examine the glycoconjugate modifications occurring in the zona pellucida during oocyte growth in fallow, red and roe deer using a battery of lectins combined with sialidase digestion and chemical treatments. This histochemical approach allowed us to sequence the oligosaccharidic side chains of the zona pellucida glycoproteins in these wild ungulates. The most effective lectins in the zona pellucida of these species were SBA, PNA, RCA-I GSA-IB4, and WGA, indicating the presence of beta-D-N-Acetylgalactosamine, beta-D-Galactose, alpha-D-Galactose and N-Acetylglucosamine residues. Additionally, sialic acid moieties were demonstrated. We also observed differences in the glycosidic residue content and in their spatial distribution, depending on the species and stage of follicle development.

[Acute urine retention: early clinical sign of a rhabdomyosarcoma of the bladder or prostate in children: report of three cases]

Acute urine retention can be the first clinical sign of a rabdomyosarcoma (RMS) of bladder and prostate. This is particularly evident in the age group comprised between 2 and 4 years. The Authors report their experience on three cases of 2 years old males admitted for acute urine retention. One case was diagnosed to have an prostate RMS, the other two a RMS of the bladder. The prostate RMS refused the operation dying 2 years after operation. Of the two cases of RMS of the bladder, one was treated successfully by polychemotherapy treatment, the second, after polychemotherapy underwent a partial cystectomy. The Authors conclude affirming the importance of a ultrasonography of the lower urinary tract in all patients with acute retention of urine, since this could be the first sign of a RMS of prostate or bladder.

Oxyphilic carcinoma of the thyroid gland

Oxyphilic tumors of the thyroid gland are rare tumors characterized by the presence of H?rthle cells - mitochondrion-rich, eosinophilic epithelial cells. H?rthle cell carcinomas (HCC) of the thyroid behave in a more aggressive fashion as compared to other well-differentiated thyroid cancers. Many recent studies have been focused on the further elucidation of pathogenesis and the role of mitochondrial hyperplasia in carcinogenesis of these neoplasms. The importance of combining morphological and genetic approaches in the study of HCC has been emphasized by the difficulties encountered in establishing adequate differential diagnostic criteria between benign and malignant forms, as well as by the resistance of HCC to radio and chemotherapy. It has been well documented that the H?rthle cells are characterized by profound aberrations in the nuclear and mitochondrial genome and by alterations in oncogenes, tumor suppressor genes and other key genes involved in energy metabolism, proliferation and apoptosis.

Can histologic changes of the upper pole justify a conservative approach in neonatal duplex ectopic ureterocele?

The aim of this study was to review the histology of the upper-pole segment in patients with duplex-system ectopic ureterocele (DEU) to determine if less aggressive surgery is justified in prenatally-diagnosed cases. The study included 15 consecutive patients with DEU treated between 1991 and 1999. The diagnosis was made according to the criteria of the Section on Urology of the American Academy of Pediatrics. The histology specimens were assessed for dysplastic, inflammatory, and obstructive changes. All 15 patients were surgically treated by heminephro-ureterectomy and the surgical specimens were histologically examined. Nine cases were diagnosed prenatally; the histology of the upper-pole segment in these patients showed segmental renal microcystic dysplasia, chondroid metaplasic islands, and an inflammatory tubulointerstitial nephropathy in 6 (66.6%) and nephroblastomatosis in 2 (22.2%). The histology of the 6 postnatally-diagnosed patients showed segmental multicystic renal dysplasia, inflammatory tubulo-interstitial nephropathy, and segmental parenchymal scars. The upper-pole histology of the prenatally-diagnosed patients did not show any evidence of reversible histologic changes. Considering this findings and the good outcome of patients treated with upper-pole nephroureterectomy, less aggressive surgery with preservation of the upper pole does not seem justified.

Weak linkage at 4p16 to predisposition for human neuroblastoma

The most frequent genetic alterations described in neuroblastoma (NB) are amplification of MYCN oncogene and deletion of chromosome 1p, although somatic deletions have been demonstrated at other chromosomal intervals. Since loss of heterozygosity (LOH) at distal 4p has been observed in about 20-29% of neuroblastomas, we have evaluated deletions in 41 Italian NB samples by LOH analysis at loci mapping to 4p as follows: pter-D4S2936-D4S412-D4S2957-D4S432-D4S3023-D4S431-cen. Our analysis showed allele losses in eight out of 41 samples (19.5%) and allowed the identification of a smallest region of overlapping deletion (SRO) of 3.0 cM, delimited by D4S412 and D4S3023. Two of these tumors with 4p LOH are from patients belonging to a family with recurrent NB. Interestingly the genotyping of this family revealed an identical haplotype that includes the nonrecombinant loci D4S412, D4S2957 and D4S432 shared by all affected children and demonstrated that this haplotype is retained in the two tumors carrying somatic deletions from patients of this family. Furthermore linkage analysis was performed in two NB families and yielded an overall lod-score of 3.0 in the interval including the haplotype. This provides a confirmatory indication that the region delimited by D4S2936 and D4S3023, which also includes the new defined SRO, may harbor NB predisposing gene/s.