Attenuation of the polypeptide 7B2, prohormone convertase PC2, and vasopressin in the hypothalamus of some Prader-Willi patients: indications for a processing defect

7B2 is a neuroendocrine chaperone interacting with the prohormone convertase PC2 in the regulated secretory pathway. Its gene is located near the Prader-Willi syndrome (PWS) region on chromosome 15. In a previous study we were able to show 7B2 immunoreactivity in the supraoptic nucleus (SON) or the paraventricular nucleus (PVN) in only three of five PWS patients. Here we report that in contrast with five other PWS patients, the neurons in the hypothalamic SON and PVN of the two 7B2-immunonegative PWS patients also failed to show any reaction using two antibodies directed against processed vasopressin (VP). On the other hand, even these two cases reacted normally with five antibodies that recognize different parts of the VP precursor. This finding pointed to a processing defect. Indeed, the same patients had no PC2 immunoreactivity in the SON or PVN, whereas PC1 immunoreactivity was only slightly diminished. In conclusion, in the VP neurons of two PWS patients, greatly reduced amounts of 7B2 and PC2 are present, resulting in diminished VP precursor processing.     

trans-encapsidation of a poliovirus replicon by different picornavirus capsid proteins

A trans-encapsidation assay was established to study the specificity of picornavirus RNA encapsidation. A poliovirus replicon with the luciferase gene replacing the capsid protein-coding region was coexpressed in transfected HeLa cells with capsid proteins from homologous or heterologous virus. Successful trans-encapsidation resulted in assembly and production of virions whose replication, upon subsequent infection of HeLa cells, was accompanied by expression of luciferase activity. The amount of luciferase activity was proportional to the amount of trans-encapsidated virus produced from the cotransfection. When poliovirus capsid proteins were supplied in trans, >2 x 10(6) infectious particles/ml were produced. When coxsackievirus B3, human rhinovirus 14, mengovirus, or hepatitis A virus (HAV) capsid proteins were supplied in trans, all but HAV showed some encapsidation of the replicon. The overall encapsidation efficiency of the replicon RNA by heterologous capsid proteins was significantly lower than when poliovirus capsid was used. trans-encapsidated particles could be completely neutralized with specific antisera against each of the donor virus capsids. The results indicate that encapsidation is regulated by specific viral nucleic acid and protein sequences.     

Aromatic stacking and bending of the DNA helix by the individual repeat units of the carboxy-terminal domain of RNA polymerase II

The carboxy-terminal domain (CTD) of RNA polymerase II consists of multiple repeats of the unique heptad sequence -(Ser-Pro-Thr-Ser-Pro-Ser-Tyr)- which may interact with DNA through the intercalation of adjacent tyrosine aromatic rings. We have examined details of the interaction of this motif with calf thymus DNA through analysis of peptide analogues that contain (1) an amino-terminal tyrosine which mimics the presence of an adjacent heptad repeat and (2) positively-charged lysine residues which facilitate the initial contact between peptide and DNA. Results of fluorescence experiments, NMR titrations, and viscometric analyses indicate that these peptides bind to the DNA helix through a non-classical intercalation mode involving partial aromatic stacking of the tyrosine rings with the Watson-Crick base pairs.     

Body composition development of adolescent white females: the Penn State Young Women''s Health Study

m-Enterococcus agar (m-Ent) has been generally considered the reference medium for faecal streptococci in bathing waters. However, it shows several shortcomings, and therefore it is important to test newly developed media that can guarantee more precise results. In this sense, the recently described oxolinic acid--esculin--azide agar medium (OAA) and m-enterococcus agar (m-Ent) were comparatively evaluated for the detection of faecal streptococci from seawater and fresh water. The OAA medium showed a significantly higher relative recovery percentage and specificity for both types of water than m-Ent. A similar spectrum of species was recorded from both media, Enterococcus faecium being predominant in fresh water and Enterococcus faecalis, in seawater. The superior performance of the OAA medium in both types of bathing waters, added to the fact that it does not require the use of complementary confirmative tests, makes this medium an excellent candidate to be employed for monitoring programmes.     

Characterization of a tobacco epoxide hydrolase gene induced during the resistance response to TMV

CD4 is the primary receptor for the human immunodeficiency virus (HIV). Nef is an accessory protein of HIV that decreases the expression of CD4 on the surface of infected cells. In this study, we identified the Nef binding protein 1 (NBP1), which interacts specifically with Nef in vitro and in vivo. Since it shares sequence similarity with the catalytic subunit of the vacuolar ATPase (V-ATPase) and complements the loss of this VMA13 gene in yeast, NBP1 is the human homolog of Vma13p. Direct interactions between Nef and NBP1 were correlated with the ability of Nef to internalize CD4. The expression of the antisense NBP1 abrogated these effects. We conclude that NBP1 helps to connect Nef with the endocytic pathway.     

Detection and identification of Mycobacterium tuberculosis directly from sputum sediments by ligase chain reaction

Sputum specimens received for the diagnosis of tuberculosis or other mycobacterial infections were tested by a ligase chain reaction (LCR)-based assay and acid-fast stain and culture techniques. Results from the LCR assay (Abbott LCx Mycobacterium tuberculosis [MTB] Assay) were compared to results from standard culture techniques held for 6 weeks. Four hundred ninety-three specimens from 205 patients suspected of pulmonary tuberculosis were included in the prospective study. Thirty-four (6.9%) of the specimens were culture positive for M. tuberculosis, and 13 (38%) of these were also fluorochrome stain positive. LCR sensitivities and specificities compared to culture were 74 and 98%, respectively. LCR sensitivity was 100% for fluorochrome stain-positive specimens and 57% for fluorochrome stain-negative specimens. Nine LCR-negative, culture-positive specimens were the result of low concentrations of M. tuberculosis. No inhibitors were detected in any of these specimens. Of the eight LCR-positive, culture-negative specimens, five were from patients with active tuberculosis. With these considered culture misses, final LCR sensitivity, specificity, positive predictive value, and negative predictive value were 77, 99, 91, and 98%, respectively. The same performance values for the fluorochrome acid-fast bacillus smear were 33, 98, 62, and 94%, respectively. After normal laboratory sputum processing, the Abbott LCx MTB Assay can be completed in 6 h. Thus, it is possible to have results available within 8 h of specimen submission.     

Specific recognition of thymic self-peptides induces the positive selection of cytotoxic T lymphocytes

Congenital alveolar proteinosis is a recently described cause of lung dysfunction and respiratory distress in term neonates. In several cases a deficiency or insufficiency of surfactant apoprotein B (SP-B) has been caused by a frameshift mutation in the gene encoding SP-B. Five full-term children in three unrelated families from The Netherlands are reported. Immunohistochemistry demonstrated large amounts of surfactant proteins A and C (SP-A and SP-C) and precursors in alveolar cells and in intra-alveolar material. Results were positive for antibovine SP-B antibody but negative for antipig SP-B1 antibody, most probably reflecting differences in the antibody specificity. The findings suggest abnormal SP-B function. In two sibs, no pre-SP-C was demonstrated in the alveoli, although it was found in considerable amounts in alveolar cells. One such case has previously been reported. In two families, the parents were heterozygous for the 121 ins 2 mutation in the SP-B gene. Our findings suggest that congenital alveolar proteinosis may result from abnormalities in one or more of the surfactant proteins.     

Influence of an oligodendroglial component on the survival of patients with anaplastic astrocytomas: a report of Radiation Therapy Oncology Group 83-02

PURPOSE: Seven percent of patients with high grade gliomas enrolled in RTOG 83-02 had mixed astrocytoma/oligodenroglial elements on central pathology review. It has often been assumed that the most aggressive histologic component of a tumor determines biologic behavior; however in this trial, the survival of patients who had mixed glioblastomas/oligodenrogliomas was significantly longer than that of patients with pure glioblastomas (GBM). We therefore evaluated the effect of an oligodendroglial component on the survival of patients who had anaplastic astrocytomas (AAF) treated in the same trial. METHODS AND MATERIALS: One hundred nine patients who had AAF and 24 patients with mixed AAF/oligodendrogliomas (AAF/OL) were enrolled in a Phase I/II trial of randomized dose-escalation hyperfractioned radiotherapy plus BCNU. AAF/OL patients were older and more likely to have had more aggressive surgery than AAF patients. Other pretreatment characteristics were balanced between groups, as was assigned treatment. RESULTS: The median survival time for AAF was 3.0 years versus 7.3 years for AAF/OL (p = 0.019). In a multivariate analysis, adjusting for extent of surgical resection and age, an oligodendroglial component was an independent prognostic factor for survival. CONCLUSION: The results support the concept that AAFs with an oligodendroglial component have a better prognosis than pure AAF tumors, similar to the effect seen among patients with glioblastoma multiforme tumors. This better survival outcome should be taken into consideration in the design and stratification of future trials. Additionally, in contrast to patients with GBMs, patients who have AAF/OL have the potential for prolonged survival; therefore, late sequelae of treatment (both radiation and chemotherapy) must be weighed more heavily in the benefits to risks analysis.     

The normal anterior commissure of the glottis

OBJECTIVE: We characterized the normal width of the anterior commissure of the glottis by measuring its dimensions on CT scans obtained in patients who had no laryngeal disorders. SUBJECTS AND METHODS: CT scans of patients referred for cervical CT myelography were prospectively reviewed by a single board-certified radiologist. Axial images through the anterior commissure (localized by vocal process of the arytenoid cartilage, the vocal muscle, or both) were magnified on the viewing console of the CT scanner. Window and level were chosen to simulate our routine settings for CT scans of the neck. Anteroposterior width of the anterior commissure was measured using an electronic ruler with 1-mm marks. RESULTS: Sixty-five patients were prospectively evaluated. Nine patients were excluded because of substantial motion artifact, and another 18 were excluded because CT images did not include the entire larynx. Thus, the final study group included 38 patients. The average width of the anterior commissure was 1.02 +/- 0.56 mm. The width was less than or equal to 1.1 mm in 22 (58%) of 38 patients. The width was less than or equal to 1.7 mm in 35 (92%) of 38 patients. Forty-two percent (16 of 38 patients) had anterior commissures wider than 1.0 mm. The maximum width of 2.2 mm was seen in only one patient. CONCLUSION: The mean width of the anterior commissure was approximately 1.0 mm. However, 42% of patients had anterior commissures wider than 1.0 mm. In our series, using an upper limit of 1.6 mm as a normal measurement for the anterior commissure would have included 92% of patients, and an upper limit of 2.1 mm would have encompassed the mean plus two SDs.