Skeletal changes in epidermal nevus syndrome: does focal bone disease harbor clues concerning pathogenesis?

Epidermal nevus syndrome (ENS) is a rare, sporadic, congenital disorder of unknown etiology featuring a complex and highly variable phenotype that can include focal or generalized skeletal disease. We describe a young man with ENS manifesting right-sided linear skin lesions, generalized weakness, diffuse osteopenia associated with hypophosphatemic rickets, and distinctive focal bone lesions ipsilateral to the skin findings. Review of the literature concerning ENS-associated skeletal disease suggested such focal bone defects are fibrous dysplasia, but our patient did not have the typical radiographic or histopathologic findings of fibrous dysplasia. Nevertheless, his circulating fibroblast growth factor 23 (FGF-23) level was elevated, likely functioning as a "phosphatonin," yet no activating mutations in GNAS previously reported in fibrous dysplasia or McCune-Albright syndrome were detected in his leukocytes or affected skin. We postulate that the focal skeletal disease, although different than fibrous dysplasia, may be a source of FGF-23 in ENS.     

Secondary amyloidosis and gastrointestinal stromal tumors. A case report and discussion of pathogenesis

A 69-year-old man presented with a malignant gastrointestinal stromal tumor associated with secondary amyloidosis. The tumor had classic features of a malignant gastrointestinal stromal tumor with interlacing fascicles and whorls of spindled cells, numerous and conspicuous mitotic figures, and extensive coagulative necrosis. The cells stained diffusely for CD117 (c-Kit), confirming the diagnosis of gastrointestinal stromal tumor. The spleen, 1 adrenal gland, and part of the pancreas were removed en block with the stomach. By microscopy, the spleen and adrenal gland were partially replaced with amyloid deposits confirmed by Congo red staining, electron microscopy, and immunohistochemistry. In contrast, neither the tumor nor the surrounding vasculature showed amyloid deposition. To our knowledge, this represents only the second case of systemic amyloidosis associated with a gastrointestinal stromal tumor. This case is unique in that extensive, diffuse amyloid deposits were observed in the spleen, adrenal gland, and liver.     

Intestinal and oncocytic variants of pancreatic intraepithelial neoplasia. A morphological and immunohistochemical study

We report 2 previously undescribed morphological variants of pancreatic intraepithelial neoplasia (PanIN). The first variant with an intestinal phenotype was associated with mucinous carcinomas that occurred in the tail of the pancreas of 2 men (60 and 65 years old). The carcinomas lacked the characteristic ovarian-like stroma of mucinous cystic neoplasms observed in female patients and did not show a papillary architecture. Whether they represent mucinous cystadenocarcinomas or mucinous carcinomas that arose from the flat variant of intraductal papillary mucinous neoplasms could not be determined with certainty. Microscopically, the intestinal type of PanIN was composed of pseudostratified columnar cells similar to those of colonic adenomas and showing variable degrees of dysplasia. A significant increase in the MIB-1 labeling index correlated with the severity of dysplasia. In contrast to conventional PanIN, the intestinal variant expressed MUC-2 and was MUC-1 negative. The second type of PanIN had an oncocytic phenotype, coexpressed MUC-2 and MUC-1 mucins, and was associated with intraductal oncocytic papillary carcinomas that showed a similar immunohistochemical mucin profile. Both intestinal and oncocytic types of PanIN expressed DPC4 and lacked p53 reactivity. The anatomical separation of the PanINs from the carcinomas and the gradual progression of cytological and architectural abnormalities in both variants of PanIN argue against ductal spread (cancerization of the ducts). The intestinal and oncocytic variants of PanIN broaden the morphological spectrum of this intraductal lesion. Although their significance is unknown, the possibility that these PanIN variants represent cancer precursors should be considered.     

Heterogeneity in synaptic transmission along a Drosophila larval motor axon

At the Drosophila melanogaster larval neuromuscular junction (NMJ), a motor neuron releases glutamate from 30-100 boutons onto the muscle it innervates. How transmission strength is distributed among the boutons of the NMJ is unknown. To address this, we created synapcam, a version of the Ca2+ reporter Cameleon. Synapcam localizes to the postsynaptic terminal and selectively reports Ca2+ influx through glutamate receptors (GluRs) with single-impulse and single-bouton resolution. GluR-based Ca2+ signals were uniform within a given connection (that is, a given bouton/postsynaptic terminal pair) but differed considerably among connections of an NMJ. A steep gradient of transmission strength was observed along axonal branches, from weak proximal connections to strong distal ones. Presynaptic imaging showed a matching axonal gradient, with higher Ca2+ influx and exocytosis at distal boutons. The results suggest that transmission strength is mainly determined presynaptically at the level of individual boutons, possibly by one or more factors existing in a gradient.     

Mutation of the signal peptide region of the bicistronic gene DSPP affects translocation to the endoplasmic reticulum and results in defective dentine biomineralization

Dentine dysplasia type II is an autosomal dominant disorder in which mineralization of the dentine of the primary teeth is abnormal. On the basis of the phenotypic overlap between, and shared chromosomal location with, dentinogenesis imperfecta type II, a second disorder of dentine mineralization, it has been proposed that the two conditions are allelic. As recent studies have shown that dentinogenesis imperfecta type II results from mutation of the bicistronic dentine sialophosphoprotein gene (DSPP ), we have tested this hypothesis by sequencing DSPP in a family with a history of dentine dysplasia type II. Our results have shown that a missense change, which causes the substitution of a tyrosine for an aspartic acid in the hydrophobic signal peptide domain of the protein, underlies the phenotype in this family. Biochemical analysis has further demonstrated that this mutation causes a failure of translocation of the encoded proteins into the endoplasmic reticulum, and is therefore likely to lead to a loss of function of both dentine sialoprotein and dentine phosphoprotein.     

Immunogenicity and efficacy of oral or intranasal Shigella flexneri 2a and Shigella sonnei proteosome-lipopolysaccharide vaccines in animal models.

Immunity against shigellosis has been shown to correlate with the presence of antibodies specific for Shigella lipopolysaccharide (LPS). We here propose a new candidate vaccine for shigellosis composed of purified Shigella flexneri 2a or Shigella sonnei LPS hydrophobically complexed with group C type 2b Neisseria meningitidis outer membrane protein proteosomes. Immunization of mice either orally or intranasally with this complex induced specific homologous anti-LPS antibodies in both intestinal and respiratory secretions as well as in sera. Strong anamnestic responses were found after two or three immunizations. LPS alone, alkaline-detoxified LPS, or alkaline-detoxified LPS complexed with proteosomes was not effective. Oral or intranasal immunization of guinea pigs with two or more doses of this proteosome-LPS vaccine elicited homologous protection against Shigella keratoconjunctivitis (Serény test). These data demonstrate that proteosomes can be used as an effective mucosal vaccine delivery system and that orally or intranasally administered acellular vaccines can protect against Shigella infections.     

Microbicides 2006 conference

Current HIV/AIDS statistics show that women account for almost 60% of HIV infections in Sub-Saharan Africa. HIV prevention tools such as male and female condoms, abstinence and monogamy are not always feasible options for women due to various socio-economic and cultural factors. Microbicides are products designed to be inserted in the vagina or rectum prior to sex to prevent HIV acquisition.     

Morphine stimulates superoxide formation by glomerular mesangial cells

Focal glomerulosclerosis is the predominant glomerular lesion in heroin addicts. We studied whether morphine, a metabolite of heroin, could directly affect the formation of superoxide by glomerular mesangial cells. Mesangial cells preincubated with morphine (10^–8 M) showed a higher (P<0.001) production of superoxide when compared to control cells (control) 401±21 vs. morphine 610±41 nM/mg protein/h). This effect of morphine on mesangial cells was dose dependent. Naloxone, an opiate antagonist, attenuated morphine-induced formation of Superoxide by mesangial cells [control, 317±4; morphine (10^–8 M), 573±9; and naloxone (10^–8 M) + morphine (10^–8 M), 333±6 nM/mg protein/h]. We conclude that morphine enhances formation of superoxide by mesangial cells and this effect of morphine seems to be mediated through opiate receptors. Since superoxide has been demonstrated to cause mesangiolysis, we propose that morphine may be playing a role in the induction of mesangial injury in patients with opiate abuse.This work was supported by National Institute of Health Grant R01-DA-06753.     

Real-time nucleic acid sequence-based amplification using molecular beacons for detection of enterovirus RNA in clinical specimens

Real-time nucleic acid sequence-based amplification (NASBA) using molecular beacon technology (NASBA-beacon) was compared to standard NASBA with postamplification hybridization using electrochemiluminescently labeled probes (NASBA-ECL) for detection of enteroviruses (EV) in 133 cerebrospinal fluid and 27 stool samples. NASBA-ECL and NASBA-beacon were similar in sensitivity, detecting 55 (100%) and 52 (94.5%) EV-positive samples, respectively. There were no false positives. Both NASBA assays were significantly more sensitive than culture. Real-time NASBA-beacon reagents and equipment rental were more expensive than those for NASBA-ECL; however, time to result was shortened by 1.5 h, hands-on time was reduced by 25 min, and the assay was much simpler for technologists to learn and perform.