The relationship of HIV status, type of coagulation disorder, and school absenteeism to cognition, educational performance, mood, and behavior of boys with hemophilia

Apnoea, bradycardia and hypotension were elicited by right atrial injections of capsaicin in anaesthetized monkeys. At the threshold dose (2.5 +/- 0.3 microgram/kg), tachypnoea was elicited (latency 1.6 +/- 0.2 s) which got replaced by apnoea with higher doses of capsaicin. These responses persisted (1) after cooling the cervical vagi to 6-8 degrees C, and (2) after instilling xylocaine into the pericardial sac. Tachypnoea and apnoea were elicited after bilateral cervical vagotomy also, but only with higher doses and after a longer latency (5.0 +/- 0.3 s). Right atrial injection of capsaicin and insufflation of halothane stimulated vagal pulmonary C-fibre receptors with a latency of 1.7 +/- 0.7 s and 0.2 +/- 0.1 s, respectively. Tachypnoea/apnoea, bradycardia and hypotension were elicited by left atrial injection of capsaicin also (threshold dose: 5.0 +/- 1.2 micrograms/kg). The respiratory responses persisted (1) after instilling xylocaine into the pericardial sac, and (2) after bilateral cervical vagotomy suggesting that they were due to stimulation of non-cardiac receptors with sympathetic afferents. It is concluded that the initial respiratory responses elicited by right atrial injection of capsaicin were due to stimulation of pulmonary C-fibre receptors with vagal afferents.     

Ocular characteristics associated with rigid gas-permeable lens adherence

PURPOSE: Rigid gas-permeable (RGP) lens adherence after overnight lens wear is clearly a patient-dependent phenomenon. However, no previous study has attempted to determine whether specific ocular characteristics are associated with an increased frequency of lens adherence. METHOD: In this study, clinically applicable tests were used to measure a range of ocular characteristics, including central and peripheral corneal curvature, tear film status, eyelid characteristics, central corneal thickness, and ocular rigidity in a group of 22 young adult subjects for whom reliable estimates for frequency of overnight RGP lens adherence had been obtained from earlier studies. RESULTS: Linear discriminant analysis revealed that a higher frequency of lens adherence was associated with lower ocular rigidity, thinner central corneas, greater eyelid tension, and lower amounts of corneal astigmatism. CONCLUSIONS: These findings suggest a clinical approach for identifying patients who may develop clinically significant lens adherence during RGP extended wear, and also provide support for the "thin film adherence" theory of RGP lens adherence.     

Desensitization of inositol 1,4,5-trisphosphate/Ca2+-induced Cl- currents by prolonged activation of G proteins in Xenopus oocytes

Expression of G protein alpha subunits of the Gq family with various G protein-coupled receptors induces activation of an inositol 1,4, 5-trisphosphate (IP3)/Ca2+-mediated Cl- conductance in Xenopus oocytes. Our present data show that two members of this family, the human Galpha16 subunit and the murine homologue Galpha15, can induce both activation and inhibition of these agonist-induced currents. Although extremely low amounts (10-50 pg) of injected Galpha16 subunit cRNA cause modest ( approximately 2-fold) enhancement of ligand-induced Cl- currents in oocytes co-injected with thyrotropin-releasing hormone (TRH) receptor cRNA 48 h postinjection, larger Galpha16 and Galpha15 cRNA injections cause >10-fold inhibition of TRH or 5HT2c receptor responses. The inhibition is analyzed in this study. The inhibited currents are recovered if various Gbetagamma subunit combinations are also expressed with the Galpha subunits. The constitutively active mutant, Galpha16Q212L, also causes a strong attenuation of the ligand-induced Cl- currents, but this inhibition is not recovered by co-expression of Gbetagamma subunits. These results indicate that the free Galpha subunit is responsible for the inhibitory signal. Although expression of TRH receptor alone produces maximum responses approximately 48 h after injection, co-expression of TRH receptor with Galpha16 results in enhanced responses 6-12 h postinjection, followed by complete attenuation at 36 h. Furthermore, injection of Galpha16 cRNA alone at comparable levels gives rise to spontaneous Cl- currents within 6-12 h postinjection, suggesting that the early spontaneous activation underlies the later suppression. Expression of other G protein alpha subunits of the Gq family, at cRNA levels considerably higher than effective for Galpha16, produces both analogous spontaneous Cl- currents and, later, inhibition of ligand-induced Cl- currents. Experiments with direct injection of IP3 and of Ca2+ suggest that this inhibition is consistent with the down-regulation of IP3 receptors. These data indicate that both enhancement and inhibition of signaling through G protein-coupled receptors can be mediated by the expression level and/or activity of an individual G protein.     

Diagnostic criteria for sporadic Creutzfeldt-Jakob disease

BACKGROUND: Making a clinical diagnosis of sporadic Creutzfeldt-Jakob disease relies on the evaluation of rapidly progressive dementia, ataxia, myoclonus, changes on the electroencephalogram, and other neurological signs. A definite diagnosis, however, is confined to cases that have been evaluated neuropathologically or by equivalent diagnostic techniques. This places a high priority on the establishment of reliable neuropathologic methods for the investigation and diagnosis of Creutzfeldt-Jakob disease. OBJECTIVE: To evaluate existing morphological and laboratory diagnostic techniques to reach a consensus on the definition of "definite Creutzfeldt-Jakob disease." METHODS: The existing morphological techniques, particularly immunohistochemistry, used in 4 laboratories--Germany, Great Britain, Japan, and the United States--are evaluated, and various laboratory diagnostic techniques are discussed. RESULTS: Immunohistochemistry with antibodies against the prion protein combined with special tissue pretreatment regimens gives reliable diagnostic results and, for its applicability to formalin-fixed and paraffin-embedded tissue, is superior to other techniques that may be more sensitive but require fresh, unfixed brain tissue. CONCLUSIONS: Our experience suggests the following regimen for the diagnosis of suspected Creutzfeldt-Jakob disease: light microscopy of various brain regions, which in typical cases may lead to definite diagnosis. Immunohistochemistry with antibodies against the prion protein is preferable in all suspected cases of Creutzfeldt-Jakob disease and is mandatory whenever a routine histological workup does not yield definite results. Additional special techniques can be applied if required.     

Characterization of rabbit DNA microsatellites extracted from the EMBL nucleotide sequence database

Microsatellite polymorphisms are invaluable for mapping vertebrate genomes. In order to estimate the occurrence of microsatellites in the rabbit genome and to assess their feasibility as markers in rabbit genetics, a survey on the presence of all types of mononucleotide, dinucleotide, trinucleotide and tetranucleotide repeats, with a length of about 20 bp or more, was conducted by searching the published rabbit DNA sequences in the EMBL nucleotide database (version 323). A total of 181 rabbit microsatellites could be extracted from the present database. The estimated frequency of microsatellites in the rabbit genome was one microsatellite for every 2-3 kb of DNA. Dinucleotide repeats constituted the prevailing class of microsatellites, followed by trinucleotide, mononucleotide and tetranucleotide repeats, respectively. The average length of the microsatellites, as found in the database, was 26, 23, 23 and 22 bp for mono-, di-, tri- and tetranucleotide repeats, respectively. The most common repeat motif was AG, followed by A, AC, AGG and CCG. This group comprised about 70% of all extracted rabbit microsatellites. About 61% of the microsatellites were found in non-coding regions of genes, whereas 15% resided in (protein) coding regions. A significant fraction of rabbit microsatellites (about 22%) was found within interspersed repetitive DNA sequences.     

Protoporphyrinogen oxidase of Myxococcus xanthus. Expression, purification, and characterization of the cloned enzyme

Protoporphyrinogen oxidase (EC 1.3.3.4) catalyzes the six electron oxidation of protoporphyrinogen IX to protoporphyrin IX. The enzyme from the bacterium Myxococcus xanthus has been cloned, expressed, purified, and characterized. The protein has been expressed in Escherichia coli using a Tac promoter-driven expression plasmid and purified to apparent homogeneity in a rapid procedure that yields approximately 10 mg of purified protein per liter of culture. Based upon the deduced amino acid sequence the molecular weight of a single subunit is 49,387. Gel permeation chromatography in the presence of 0.2% n-octyl-beta-D-glucopyranoside yields a molecular weight of approximately 100,000 while SDS gel electrophoresis shows a single band at 50,000. The native enzyme is, thus, a homodimer. The purified protein contains a non-covalently bound FAD but no detectable redox active metal. The M. xanthus enzyme utilizes protoporphyrinogen IX, but not coproporphyrinogen III, as substrate and produces 3 mol of H2O2/mol of protoporphyrin. The apparent Km and kcat for protoporphyrinogen in assays under atmospheric concentrations of oxygen are 1.6 microM and 5.2 min-1, respectively. The diphenyl ether herbicide acifluorfen at 1 microM strongly inhibits the enzyme's activity.     

Efficacy of radical hysterectomy as treatment for patients with small cell carcinoma of the cervix

BACKGROUND: This study was performed to identify pathologic and clinical features that best predict disease free survival of patients with early stage small cell carcinoma of the cervix treated by radical hysterectomy. METHODS: Three hundreds and seventy patients with cervical carcinoma were analyzed retrospectively to define those variable that best predict disease free survival (DFS). Variables included age, weight, race, marital status, economic status, tumor size, depth of invasion (DI), lymph-vascular space involvement (LVSI), cell type, tumor grade, lymph node metastasis (LNM), and total number of lymph nodes removed. Patients with lymph node metastasis, parametrial involvement, and positive or close surgical margins were offered postoperative radiation. RESULTS: Twelve patients were found to have small cell carcinoma (3.2%). One patient had microinvasive carcinoma of the cervix (MIC) as defined by the Society of Gynecologic Oncologists with a depth of invasion of 3 mm or less and no lymph-vascular space invasion, and has been reported previously. A detailed analysis of the other patients with nonsmall cell carcinoma is presented separately. Five patients achieved a DFS of at least 5 years, whereas 7 patients died with disease. Excluding the patient with MIC, the 5-year DFS rate was 36.4%. CONCLUSIONS: Relative to other cell types, small cell carcinomas of the cervix is an aggressive neoplasm with a higher rate of LVSI and LNM despite smaller DI and tumor size. These data suggest that multimodality therapy, combining radical surgery and radiation with cytotoxic chemotherapy, may provide these patients with the best chance for cure.