No association between the Pro197Leu polymorphism in the glutathione peroxidase (GPX1) gene and schizophrenia

OBJECTIVE: Oxidative stress such as free radical-mediated neuronal dysfunction may be involved in the pathophysiology of schizophrenia. The human glutathione peroxidase (GPX1) is a selenium-dependent enzyme, which plays an important role in the detoxification of free radicals. We therefore hypothesized that the GPX1 gene, which is located on chromosome 3p21.3, may be involved in the pathophysiology of schizophrenia. The aim of this study is to examine whether a potentially functional polymorphism, a proline (Pro) to leucine (Leu) substitution at codon 197 (Pro197Leu) of the human GPX1 gene, is associated with susceptibility to schizophrenia. METHODS: We genotyped the Pro197Leu polymorphism in a total of 113 nuclear families that had a proband with schizophrenia. Genetic association was tested using the transmission disequilibrium test (TDT), the sib transmission disequilibrium test (STDT), and the family-based association test (FBAT). RESULTS: The minor allele (Leu) frequency was calculated to be 0.282. We could not find significant transmission disequilibrium of the alleles for the Pro197Leu polymorphism in the GPX1 gene in association with the presence of schizophrenia in our family sample (TDT, chi2=0.03, degrees of freedom=1, P=0.86; combined TDT-STDT, Z'=-0.052, P=0.47; FBAT, Z=0.000, P=1.000). CONCLUSION: The results of this study suggest that the GPX1 polymorphism is unlikely to be associated with susceptibility to schizophrenia.     

Depolarization-induced retrograde synaptic inhibition in the mouse cerebellar cortex is mediated by 2-arachidonoylglycerol

Endocannabinoids acting on CB₁ cannabinoid receptors are involved in short- and long-term depression of synaptic transmission. The aim of the present study was to determine which endocannabinoid, anandamide or 2-arachidonoylglycerol (2-AG), is involved in depolarization-induced suppression of inhibition (DSI) in the cerebellar cortex, which is the most widely studied form of short-term depression. Depolarization of Purkinje cells in the mouse cerebellum led to an increase in intracellular calcium concentration and to suppression of the inhibitory input to these neurons (i.e. DSI occurred). Orlistat and RHC80267, two blockers of sn -1-diacylglycerol lipase, the enzyme catalysing 2-AG formation, abolished DSI by acting downstream of calcium influx. In contrast, DSI occurred also in the presence of a phospholipase C inhibitor. Intact operation of the calcium-dependent messengers calmodulin and Ca²⁺–calmodulin-dependent protein kinase II were necessary for DSI. DSI was potentiated by an inhibitor of the main 2-AG-degrading enzyme, monoacylglycerol lipase. Interference with the anandamide metabolizing enzyme, fatty acid amide hydrolase, did not modify DSI. Thus, three kinds of observations identified 2-AG as the endocannabinoid involved in DSI in the mouse cerebellum: DSI was abolished by diacylglycerol lipase inhibitors; DSI was potentiated by a monoglyceride lipase inhibitor; and DSI was not changed by an inhibitor of fatty acid amide hydrolase. Further experiments indicated that 2-AG is the endocannabinoid mediating short-term retrograde signalling also at other synapses: orlistat abolished DSI in the rat cerebellum, DSI in the mouse substantia nigra pars reticulata and depolarization-induced suppression of excitation in the mouse cerebellum.     

CD10 is expressed in a subset of chromophobe renal cell carcinomas.

CD10 has been considered a useful marker in the diagnosis of renal carcinomas, because of its expression in clear cell and papillary renal cell carcinomas and its absence in chromophobe renal cell carcinomas. On the other hand, chromophobe renal cell carcinoma expresses parvalbumin, which is absent in clear cell and papillary renal cell carcinomas. To further address the relevance of these markers, we studied the expression of CD10 and parvalbumin in 42 samples of chromophobe renal cell carcinoma (seven of which had aggressive features, including invasion beyond the renal capsule, renal vein invasion, metastases, or sarcomatoid transformation), 75 clear cell renal cell carcinomas (eight metastatic) and 51 papillary renal cell carcinomas (two metastatic). CD10 was found in 100% of clear cell renal cell carcinomas, 63% of papillary renal cell carcinomas and in all metastatic cases of both types. At variance with previous studies, we found CD10 expression in from 30 to 90% of the neoplastic cells, in 11 of 42 (26%) chromophobe renal cell carcinomas. The CD10-positive cases included five of the seven (71%) chromophobe renal cell carcinoma with aggressive features. Statistical analysis showed significant association of CD10-positive tumors with clinicopathologic aggressiveness (P=0.003) and mitotic figures (P=0.04). Parvalbumin was strongly expressed in all primary and metastatic chromophobe renal cell carcinomas. Western blot analysis was utilized to confirm the expression of both CD10 and parvalbumin in chromophobe renal cell carcinomas.     

Basaloid carcinoma of the pancreas

A case of basaloid carcinoma of the pancreas in a 26-year-old woman is reported. The tumour was constituted by solid nests of relatively uniform neoplastic cells with hyperchromatic nuclei and scant cytoplasm, showing distinct peripheral palisading. There were necrotic areas and deposition of hyaline material, suggesting a basement membrane-like substance. Small foci of clear-cut squamous differentiation were present. Tumour cells were positive for cytokeratin 14 and P63 and negative for neuroendocrine and acinic cell markers. Ultrastructurally, the tumour was constituted by polygonal cells with round nuclei containing clumped chromatin. Occasional tight junctions and keratin filaments were present. Basaloid carcinomas may arise in several sites of the body, the most frequent being the anus and oesophagus, and have poor clinical outcome. The present case appears to be, to the best of our knowledge, the first documented example in the literature of basaloid carcinoma of the pancreas.     

Ultrastructural Features of Neuroendocrine Differentiated Carcinomas of the Breast

The ultrastructural patterns of neuroendocrine (NE) differentiated breast carcinomas are analyzed and discussed. Reports in the literature describe wide variations in the size of observed dense-core membrane-bound granules and discrepancies in their interpretation. In the present study 24 cases of breast carcinoma with recognized morphologic, histochemical, and immunocytochemical features of NE tumors were investigated. Five different types of dense-core granules of neurosecretory (NS) type (confirmed by the ultrastructural localization of chromogranin A) and five different cell types were recognized. Some amphicrine cells were found to contain both mucin and NS granules. Another notable ultrastructural feature of breast NE carcinomas was the presence of clear vesicles of presynaptic type, which correlated with expression of synaptophysin.     

Gastrointestinal mesenchymal tumors - immunophenotypic classification and survival analysis

The current definition of gastrointestinal tumors (GIST) as CD117-positive mesenchymal tumors of uncertain malignant potential fails to include a number of cases with similar histology. In an attempt to improve the classification of these neoplasms, we conducted an immunohistochemical analysis of 244 mesenchymal tumors with histological features of GIST. According to their immunophenotype, the tumors were classified as GISTs, which are characterized by CD117 (c-kit) expression; gastrointestinal CD117-negative CD34 positive stromal tumors (GINST); alpha-smooth muscle actin and/or desmin positive gastrointestinal leiomyogenic tumors (GILT); S-100 and glial fibrillary acidic protein positive gastrointestinal glial/schwannian tumors (GIGT); gastrointestinal neuronal/glial tumors (GINT), which are positive for S-100/glial fibrillary acidic protein plus neuronal/glial markers; and gastrointestinal fibrous tumors (GIFT), which are only vimentin positive. The most common type of tumors were GIST, followed in order of frequency by GINST, GILT, GIGT, GIFT, and GINT. GISTs did not show any preferential location, whereas GINSTs occurred almost exclusively in the stomach and duodenum, and GILTs preferentially in the large intestine. Over a median follow-up period of 71 months, malignant behavior, i.e., metastatic spread, was observed in all tumor types except GINTs. Malignancy was associated with distal gut location, high mitotic activity, large tumor size, and nuclear pleomorphism, though none of these criteria alone discriminated between benign and malignant. Kaplan-Meier analysis of disease-specific survival showed significant differences in the long-term outcome of the newly defined subgroups. We conclude that, despite strong morphological similarities, gastrointestinal mesenchymal tumors are heterogeneous in their immunophenotype and biology.     

Dipolar sources of the early scalp somatosensory evoked potentials to upper limb stimulation Effect of increasing stimulus rates

Brain electrical source analysis (BESA) of the scalp electroencephalographic activity is well adapted to distinguish neighbouring cerebral generators precisely. Therefore, we performed dipolar source modelling in scalp medium nerve somatosensory evoked potentials (SEPs) recorded at 1.5-Hz stimulation rate, where all the early components should be identifiable. We built a four-dipole model, which was issued from the grand average, and applied it also to recordings from single individuals. Our model included a dipole at the base of the skull and three other perirolandic dipoles. The first of the latter dipoles was tangentially oriented and was active at the same latencies as the N20/P20 potential and, with opposite polarity, the P24/N24 response. The second perirolandic dipole showed an initial peak of activity slightly earlier than that of the N20/P20 dipolar source and, later, it was active at the same latency as the central P22 potential. Lastly, the third perirolandic dipole exaplaining the fronto-central N30 potential scalp distribution was constantly more posterior than the first one. In order to evaluate the effect of an increasing repetition frequency on the activity of SEP dipolar sources, we applied the model built from 1.5-Hz SEPs to traces recorded at 3-Hz and 10-Hz repetition rates. We found that the 10-Hz stimulus frequency reduced selectively the later of the two activity phases of the first perirolandic dipole. The decrement in strength of this dipolar source can be explained if we assume that: (a) the later activity of the first perirolandic dipole can represent the inhibitory phase of a “primary response”; (b) two different clusters of cells generate the opposite activities of the tangential perirolandic dipole. An additional finding in our model was that two different perirolandic dipoles contribute to the centro-parietal N20 potential generation. Received: 5 August 1997 / Accepted: 26 November 1997     

Stem cell therapy for neurodegenerative diseases: the issue of transdifferentiation

In the past few years research on stem cells has exploded as a tool to develop potential therapies to treat incurable neurodegenerative diseases. Stem cell transplantation has been effective in several animal models, but the underlying restorative mechanisms are still unknown. Several events such as cell fusion, neurotrophic factor release, endogenous stem cell proliferation, and transdifferentiation (adult cell acquisition of new unexpected identities) may explain therapeutic success, in addition to replacement of lost cells. This issue needs to be clarified further to maximize the potential for effective therapies. Preliminary stem transplantation trials have already been performed for some neurodegenerative diseases. There is no effective pharmacological treatment for amyotrophic lateral sclerosis, but recent preliminary data both in experimental and clinical settings have targeted it as an ideal candidate disease for the development of stem cell therapy in humans. This review summarizes recent advances gained in stem cell research applied to neurodegenerative diseases with a special emphasis to the criticisms put forward.     

Pattern and distribution of immunoglobulin VH gene usage in a cohort of B-CLL patients from a Northeastern region of Italy.

We analyzed individual VH gene rearrangements in 55 consecutive B-chronic lymphocytic leukemia (B-CLL) patients collected from a northeastern region of Italy, stressing the possible differences related to geographic characteristics of the cohorts studied. Considering the percentage of somatic mutations present in the VH gene sequences and using the 98% cut-off value, 38 of the 55 B-CLL (69%) patients displayed somatic hypermutations and 17 (31%) had a germline configuration. Our results confirm and extend the observations of a bias in the use of certain VH, DH, and JH genes among B-CLL cells. The most frequently used VH genes were VH1-69 (12.7%) with VH3-23 (12.7%) and VH4-34 (10.9%). Collectively these genes accounted for 36.3% of the cases. In the mutated cases, the range of mutations varied from 2% to 15%, with a median of 6.5%. VH1-69 (7 cases, all unmutated) carried few mutations as opposed to VH3-23 (7 cases, 5 of which mutated), VH4-34 (6 cases, all mutated), and VH3-30 (5 cases, all mutated), which show a high load of mutations. D3 family genes were found frequently (38.1%) followed by D2 (27.2%) and D6 (18.1%). The individual D segment most frequently used was D3-3, which was present in 16.3% of cases. There was predominance of the JH4 gene (49%) followed by JH6 (40%). Analysis of the distribution of replacement and silent mutations in the mutated sequences using the method of Lossos showed in 39.4% of cases evidence of antigen selection in the framework region and/or complementary determining regions. In comparison with a recent study on B-CLL patients from the Mediterranean area, the VH4-34 gene was significantly overused in the mutated group at a percentage double that of the Italian cohort reported in this study (10.9% vs. 5%), but at a frequency similar to the entire Mediterranean region (10.7%). We also found an over-representation of VH1-69 usage in the germline group, at a frequency (12.7%) higher than previously described by the same authors (Italian 8%, Mediterranean 10.7%). On the contrary, VH3-07 and VH3-49 were not much used in our study (5.4% and 1.8%, respectively) compared with the Italian group (8% and 5.1%). In our study, VH3-23 gene segment was frequently expressed, at frequency as high as that of VH1-69, a finding in keeping with reported B-CLL Italian data, but higher than the entire series of the Mediterranean area (12.7% vs. 9.2%); VH3-21 gene, frequently expressed in northern European CLL but rarely in the Mediterranean area, was completely absent. This biased usage of VH family genes may reflect a geographic leukemic repertoire, perhaps owing to a peculiar genetic background, depending on variations in germline composition of the IgVH locus or to the effect of a potential environmental element less frequently encountered in different regions.