Natural history of multiple hereditary osteochondromatosis of the lower extremity and ankle.

In this study the authors evaluated the natural history of the ankle joint in patients with multiple hereditary osteochondromatosis. Thirty-eight subjects with an average age of 42 years completed a detailed subjective questionnaire and underwent clinical and radiographic evaluation of their ankles. Three subjects (8%) indicated their ankle involvement affected their vocation, and 12 (32%) were limited in recreational sports. Seven patients (18%) had pain in at least one ankle on a weekly basis, with an average ankle pain score of 2.2. Ankle range of motion averaged 50 degrees and subtalar motion was considered normal in two thirds of ankles. Radiographic evaluation documented an average tibiotalar tilt of 9 degrees of ankle valgus, with evidence of degenerative joint disease noted in 14 ankles (19%). Those with arthritic changes had significantly more tibiotalar tilt and diminished ankle range of motion compared with those without radiographic signs of osteoarthritis. These findings document measurable decreases in ankle function and suggest that correction or prevention of excessive tibiotalar tilt may be warranted to improve outcome.     

Continuous potential display of ictal electrocorticography.

The objective of this study was to determine whether the animation of electrical activity recorded on ictal electrocorticograms (ECoGs) can demonstrate the propagation of seizure discharges from the epileptogenic zone (EZ) to the surrounding cortical area. A computer program, continuous potential display (CPD), was designed to animate the color-coded potential changes in 5-msec intervals at each recorded site. This program was used to analyze 35 ictal ECoGs recorded by subdural grid electrodes from 11 subjects who underwent epilepsy surgery for intractable partial seizures. Continuous potential display demonstrated recurrent cycles of seizure propagation from the EZ to the surrounding cortical area even when seizure discharges appeared widespread on ECoG. Hence, the EZ could be mapped at any time during the seizure course. The EZ mapped by analyzing a small fraction of ECoG during widespread seizure discharges using CPD only overlapped 69 +/- 24% (mean +/- standard deviation) of the surgical area. The EZ mapped by CPD had 34 +/- 22% false positives and 35 +/- 27% false negatives. Animation of potential changes recorded by ictal ECoG can assist in studying the temporal and spatial patterns of seizure propagation and in mapping the EZ for surgical resection.     

Epidermal growth factor transcription, translation, and signal transduction by rat type II pneumocytes in culture.

Epidermal growth factor (EGF) is known to induce fetal lung maturation and its receptor is present in the lungs of several species. Recently, EGF has been immunolocalized in type II pneumocytes in rat lung. We postulated that EGF is synthesized in type II pneumocytes and that, because of its position-restricted distribution within the alveolus, EGF might act as an autocrine regulator of type II pneumocyte function. Herein, we have tested the hypothesis using adult rat type II pneumocytes in primary culture. In situ hybridization, using an oligonucleotide probe corresponding to amino acid residues 1070 to 1081 of mouse EGF precursor, demonstrated the presence of EGF precursor mRNA. Upon S-200 Sephacryl gel chromatography of type II pneumocyte extracts, EGF-reactive protein eluted as a high-molecular-weight form (greater than 100 kD). EGF immunoreactivity was localized within type II pneumocytes in the periphery of groups of 10 to 15 cells in culture. The type II pneumocytes bound [125I]EGF in a specific manner, indicating the presence of EGF receptors. Scatchard plots gave an apparent affinity constant (Ka) of 1 x 10(9) liters/mol, and the number of receptors was estimated to be 4.8 x 10(11) mg protein (50 per cell). EGF receptor binding specificity was confirmed by the absence of an autoradiographic signal for cells incubated in the presence of a 100-fold excess concentration of transforming growth factor-alpha. Binding of [125I]EGF could also be downregulated 95% by incubation with 0.2 nM transforming growth factor-alpha.(ABSTRACT TRUNCATED AT 250 WORDS)     

gamma-Hydroxybutyric acid binding sites: evidence for coupling to a chloride anion channel

The effect of eight anions, including chloride, on the binding of gamma-hydroxy[2,3-3H]butyric acid (GHB) to synaptosomal membranes of rat and human brain was ascertained, as was the effect of a number of other allosteric modulators of the GABA/benzodiazepine/picrotoxin complex. All ions which were active at the chloride ion channel, inhibited the binding of [3H]GHB in a dose-dependent manner, with maximum inhibition of binding being 60% of 300 mM concentration of anion. Inactive ions in this binding system included sulfate, acetate and fluoride, all impermeable to the chloride ion channel. The inhibition of binding was temperature-dependent, being abolished at 37 degrees C and was independent of the cation used. The binding of [3H]GHB was also enhanced by pentobarbital, picrotoxin and diazepam but unchanged in the presence of GABA, muscimol, bicuculline, baclofen or strychnine. These data raise the possibility that the epileptogenic effect of GHB may be modulated by an action on the chloride ion channel, that is tightly coupled to the GABA/benzodiazepine/picrotoxin and/or GHB receptor complex.     

Prostate-specific antigen as a biomarker of condom failure: comparison of three laboratory assays and self-reported condom use problems in a randomized trial of female condom performance

BackgroundProstate-specific antigen (PSA), a biomarker for semen exposure, may provide a more objective measure of condom failure than subject self-reports. Methods for measuring PSA vary and their comparability with respect to assessing condom performance has not been adequately evaluated. This study compared results from three different PSA assays of vaginal samples collected by subjects in a randomized clinical trial which compared the performance of female condoms.Study DesignWe selected 30 pairs of pre- and post-coital vaginal samples from subjects who reported condom functionality problems or whose original PSA assay was positive. Samples were retested using three different PSA assays [quantitative enzyme-linked immunoassay (EIA), rocket immune-electrophoresis (RIE) and chromatographic immunoassay (CIA)]. We compared the proportion of condom uses where the post-coital PSA result indicated semen exposure for each of the three assays.ResultsDespite varying levels of sensitivity, the results from all three assays were remarkably consistent. Self-reported condom failures did not correlate well with positive PSA results, suggesting that exclusive reliance on either PSA or user self-report may be inadequate for assessing condom functionality.ConclusionIn combination with user self-report of condom failure, PSA testing provides a reliable, objective marker of condom functionality. Studies based on PSA testing may improve on conventional contraceptive clinical trials by offering a more direct assessment of a condom product's ability to prevent semen exposure.     

Construction and identification of mouse amelogenin cDNA clones.

The determination of the biochemical phenotype of tooth epithelium requires specification by the dental mesenchyme. This is a general feature of epithelial-mesenchymal interaction in a number of different epidermal organ systems (e.g., salivary gland, mammary gland, feather, skin, and hair morphogenesis). To investigate these developmental processes, we have identified a cDNA clone representing the major group of gene products associated with enamel extracellular matrix formation. The mRNAs for mouse amelogenins, representing approximately equal to 90% of the total enamel proteins, have been isolated and partially characterized by specific immunoprecipitation. The poly(A)-containing RNAs were used for the synthesis and cloning of the mouse amelogenin cDNA. Recombinant plasmids containing amelogenin cDNA sequences were identified by differential hybridization, hybrid-selected translation, and blot hybridization analyses. A cloned sequence was used to identify the expression of amelogenins during tooth development. The mouse cDNA sequence hybridized to genomic mouse and human DNAs. This amelogenin cDNA probe now enables molecular investigations of a number of classical problems in developmental biology.     

Of mice and men: anatomy of the amelogenin gene

Mammalian enamel matrix is composed of two principal proteins, the enamelins and amelogenin. Recombinant complementary DNA (cDNA) molecules for the predominant mouse amelogenin have been identified, characterized by direct determination of the DNA sequence, and used as a specific hybridization probe. The spatial- and temporal-restricted pattern for amelogenin gene expression within developing mouse molars has been traced at the level of a single cell using in situ hybridization. The mouse genome has been shown to contain only one copy of the amelogenin (AMEL) gene which is not amplified or rearranged during ameloblast determination. In contrast, the human genome contains two copies of the AMEL gene, one residing on the X chromosome and one upon the Y chromosome. These observations, the availability of specific enamel gene probes coupled with the application of new techniques in molecular biology now afford unique opportunities for the analysis of the molecular basis of inherited defects of human enamel such as amelogenesis imperfecta. Recent advances towards obtaining a physical map and the complete nucleotide sequence for the human genome, as well as the documented developmental biology, defined genetics and transgenic capability of the mouse, suggest that mouse and man are the most relevant and potentially informative models for analysis of normal and abnormal enamel biomineralization.