Immunoreactive somatostatin-28(1-12) is increased in Huntington's disease

Somatostatin-28(1-12) concentrations were measured in Huntington's disease (HD) postmortem tissue using a specific radioimmunoassay. Concentrations of immunoreactive somatostatin-28(1-12) were significantly increased in the caudate and putamen but were unchanged in cortical areas A9 and A17. Since somatostatin-28(1-12) terminates with the amino acids Arg-Glu-OH, we examined whether this dodecapeptide compound might exert a neurotoxic effect. Injections of somatostatin-28(1-12) into rat striatum showed no evidence of histologic damage.     

Primary gastrointestinal stromal tumor of the esophagus in an HIV-positive patient

We describe a rare case of malignant gastrointestinal stromal tumor (GIST) of the esophagus presenting in an HIV-positive man. Not only did the tumor arise from an unusual anatomic site for GIST, namely, the esophagus, but it also had a predominant epithelioid cell morphology that is uncommon and preferentially associated with aggressive behavior. Exhaustive immunohistochemical studies showed strong reactivities to the classic GIST marker, CD34, and to the current more sensitive and more specific GIST marker, CD117/ c-kit protein. This immunophenotype corresponded to that of stromal tumors arising in the more common sites like stomach and small intestine as well as to that of a reported series of esophageal GISTs in the general population. Mutations of the c-kit protein was detected in the tumor, confirming previous observations. This further documents that esophageal GIST and the more common benign esophageal spindle cell lesions are pathologically distinct entities and despite its rarity, esophageal GIST should be recognized by pathologists and clinicians. The occurrence of this tumor in an HIV-positive patient is coincidental, and it resulted in an extremely unusual metastatic site that has not been reported for GISTs.     

Persistent infection of SARS coronavirus in colonic cells in vitro

Severe acute respiratory syndrome coronavirus (SARS-CoV) can produce gastrointestinal symptoms. The intestinal tract is the only extrapulmonary site where viable viruses have been detected. This study examined seven established human intestinal cell lines, DLD-1, HCT-116, HT-29, LoVo, LS-180, SW-480 and SW-620, for their permissiveness to SARS-CoV infection. The results showed that only LoVo cells were permissive to SARS-CoV infection as evident by positive findings from indirect immunofluorescence staining for intracellular viral antigens, in situ hybridization for intracellular viral RNA, and electron microscopy for intracellular viral particles. In contrast to Vero cells, SARS-CoV did not produce cytopathic effects on LoVo cells. However, LoVo cells were found to be highly permissive for productive infection with a high viral titre (>3 x 10(7) viral copies/ml) produced in culture supernatant following a few days of incubation. SARS-CoV established a stable persistent chronic infection that could be maintained after multiple passages. Being a cell line of human origin, LoVo cells could be a useful in vitro model for studying the biology and persistent infection of SARS-CoV. Our results on the expression of angiotensin-converting enzyme 2 (ACE2), a recently identified cellular receptor for SARS-CoV, in these cell lines indicated that it might not be the sole determinant for cells to be susceptible to SARS-CoV infection.     

gamma-Aminobutyric acid enables synaptogenesis in the intact superior cervical ganglion of the adult rat

Local gamma-aminobutyric acid (GABA) application into the intact superior cervical ganglion (SCG) of the adult rat allows active innervation of a surgically implanted hypoglossal nerve in addition to the normal nerve supply of the ganglion. In GABA-treated SCG of the adult rat, action potentials could be obtained on stimulation of both the preganglionic nerve trunk and the implanted hypoglossal nerve. Both action potentials were reversibly sensitive to hexamethonium bromide indicating new cholinergic synapses established between axons in the hypoglossal nerve and principal sympathetic neurons. If GABA treatment of the ganglion was omitted, the double innervation did not develop after hypoglossal nerve implantation.     

Antigenic and immunogenic investigation of B-cell epitopes in the nucleocapsid protein of peste des petits ruminants virus

Attempts were made to identify and map epitopes on the nucleocapsid (N) protein of peste des petits ruminants virus (PPRV) (Nigeria75/1 strain) using seven monoclonal antibodies (MAbs) and deletion mutants. At least four antigenic domains (A-I, A-II, C-I, and C-II) were identified using the MAbs. Domains A-I (MAb 33-4) and A-II (MAbs 38-4, P-3H12, and P-13A9) were determined to be located on the amino-terminal half (amino acids [aa] 1 to 262), and domains C-I (P-14C6) and C-II (P-9H10 and P-11A6) were within the carboxy-terminal region (aa 448 to 521). Nonreciprocal competition between A-II MAbs and MAbs to C-I and C-II domains was observed, indicating that they may be exposed on the surface of the N protein and spatially overlap each other. Blocking or competitive enzyme-linked immunosorbent assay studies using PPRV serum antibodies revealed that epitopes on the domains A-II and C-II were immunodominant, whereas those on the domains A-I and C-I were not. The competition between MAb and rinderpest virus (RPV) serum antibodies raised against RPV strain LATC was found in two epitopes (P-3H12 and P-13A9) on the domain A-II, indicating that these epitopes may cause cross-reactivity between PPRV and RPV. Identification of immunodominant but PPRV-specific epitopes and domains will provide the foundation in designing an N-protein-based diagnostic immunoassay for PPRV.     

Multiple pathways to tumor immunity and concomitant autoimmunity

Summary: The immune repertoire contains T cells and B cells that can recognize autologous cancer cells. This repertoire is directed against self, and in some cases altered self (mutations). Priming immune responses against self antigens can be difficult. Strategies are presented using altered self to elicit immunity against self in poorly immunogenic tumor models. Mechanisms underlying immunity to self antigens on cancer cells show that the immune system can use diverse strategies for cancer immunity, in both the immunization and the effector phases. CD4⁺ T cells are typically, but not always, required for immunization. The effector phase of tumor immunity can involve cytotoxic T cells, macrophages with activating Fc receptors, and/or killer domain molecules. This diversity in the effector phase is observed even when immunizing with conserved paralogs. A consequence of tumor immunity is potentially autoimmunity, which may be undesirable. Autoimmunity uses similar mechanisms as tumor immunity, but tumor immunity and autoimmunity can uncouple. These studies open up strategies for active immunization against cancer.     

The effects of school-based intervention programs on aggressive behavior: a meta-analysis

Research on the effectiveness of school-based programs for preventing or reducing aggressive behavior was synthesized with a meta-analysis. Changes in aggressive behavior between pretest and posttest were analyzed for developmental patterns and characteristics associated with differential effects. Control groups showed little change in aggressive behavior, but there were significant reductions among intervention groups. Most studies were conducted on demonstration programs; the few studies of routine practice programs showed much smaller effects. Among demonstration programs, positive outcomes were associated with a variety of study, subject, and intervention characteristics. Most notably, higher risk youth showed greater reductions in aggressive behavior, poorly implemented programs produced smaller effects, and different types of programs were generally similar in their effectiveness, other things equal.     

Noradrenergic neuronal development is impaired by mutation of the proneural HASH-1 gene in congenital central hypoventilation syndrome (Ondine's curse)

Congenital central hypoventilation syndrome (CCHS, Ondine's curse) is a rare disorder of the chemical control of breathing. It is frequently associated with a broad spectrum of dysautonomic symptoms, suggesting the involvement of genes widely expressed in the autonomic nervous system. In particular, the HASH-1-PHOX2A-PHOX2B developmental cascade was proposed as a candidate pathway because it controls the development of neurons with a definitive or transient noradrenergic phenotype, upstream from the RET receptor tyrosine kinase and tyrosine hydroxylase. We recently showed that PHOX2B is the major CCHS locus, whose mutation accounts for 60% of cases. We also studied the proneural HASH-1 gene and identified a heterozygous nucleotide substitution in three CCHS patients. To analyze the functional consequences of HASH-1 mutations, we developed an in vitro model of noradrenergic differentiation in neuronal progenitors derived from the mouse vagal neural crest, reproducing in vitro the HASH-PHOX-RET pathway. All HASH-1 mutant alleles impaired noradrenergic neuronal development, when overexpressed from adenoviral constructs. Thus, HASH-1 mutations may contribute to the CCHS phenotype in rare cases, consistent with the view that the abnormal chemical control of breathing observed in CCHS patients is due to the impairment of noradrenergic neurons during early steps of brainstem development.     

Abeta-degrading endopeptidase,neprilysin, in mouse brain: synaptic and axonal localization inversely correlating with Abeta pathology

Metabolism of amyloid-beta peptide (Abeta) is closely associated with the pathology and etiology of Alzheimer's disease (AD). Since neprilysin is the only rate-limiting catabolic peptidase proven by reverse genetics to participate in Abeta metabolism in vivo, we performed detailed immunohistochemical analysis of neprilysin in mouse brain using neprilysin-deficient mice as a negative control. The aim was to assess, at both the cellular and subcellular levels, where Abeta undergoes neprilysin-dependent degradation in the brain and how neprilysin localization relates to Abeta pathology in amyloid precursor protein (APP)-transgenic mice. In hippocampus, neprilysin was present in the stratum pyramidale and stratum lacunosum-moleculare of the CA1-3 fields and the molecular layer of the dentate gyrus. Confocal double immunofluorescence analyses revealed the subcellular localization of neprilysin along axons and at synapses. This observation suggests that after synthesis in the soma, neprilysin, a type II membrane-associated protein, is axonally transported to the terminals, where Abeta degradation is likely to take place. Among various cell types, GABAergic and metabotropic glutamate 2/3 receptor-positive neurons but not catecholaminergic or cholinergic neurons, expressed neprilysin in hippocampus and neocortex, implying the presence of a cell type-specific mechanism that regulates neprilysin gene expression. As expected, Abeta deposition correlated inversely with neprilysin expression in TgCRND8 APP-transgenic mice. These observations not only support the notion that neprilysin functions as a major Abeta-degrading enzyme in the brain but also suggest that down-regulation of neprilysin activity, which may be caused by aging, is likely to elevate local concentrations of Abeta at and around neuronal synapses.