Aging and the effects of MK-801 on anoxic damage in rat hippocampal slices

A high-performance liquid chromatography assay for hydroxyurea in human serum was developed based on a commercial colorimetric assay kit for urea (Sigma Diagnostics). Serum (0.5 ml), spiked with methylurea as an internal standard, was treated with 70% perchloric acid. Supernatant (0.2 ml) was combined with 0.7 ml of BUN acid reagent and 0.6 ml of BUN color reagent. The resulting colored reactant (100 microl) was analyzed on a 300 x 3.9 mm Bondclone 10 C18 column coupled with a UV-Vis detector, at 449 nm. The mobile phase was 13% acetonitrile in water. Retention times of colored derivatives of hydroxyurea and methylurea were 6.5 and 12.2 min, respectively. The log-log calibration curve was linear from 0.0065 to 1.31 mM. Average accuracy was 99.9+/-4.0% and the intra- and inter-day error of assay did not exceed 11%.     

The sequence of Giardia small subunit rRNA shows that voles and muskrats are parasitized by a unique species Giardia microti

OBJECTIVES: To present our experience with the results of three different methods of treatment of idiopathic varicoceles. METHODS: A total of 301 patients with 417 varicoceles were retrospectively assigned into three groups according to the method of treatment. Group 1 included 94 patients with 131 varicoceles treated by open surgery. Group 2 consisted of 120 patients with 163 varicoceles treated by percutaneous retrograde sclerotherapy, and in group 3, 87 patients with 123 varicoceles were treated by laparoscopic varicocelectomy. Of all patients, 222 (73.8%) were closely followed up with clinical and Doppler ultrasound examinations 6 and 12 months after the treatment. Seminal analysis was carried out before treatment and repeated in 172 patients with subfertility or infertility 4 to 6 months after treatment. RESULTS: Patients in the three treatment groups were balanced regarding the different variables. The mean operative time was significantly shorter among patients with open surgery. The cost of sclerotherapy is one fourth to one fifth that of surgery and the cost of laparoscopy is double. Sclerotherapy was successful in 96 (82.8%) of 116 left varicoceles and in only 24 (51%) of 47 right varicoceles. The recurrence rate at follow-up was not significantly different among the three groups. The recurrence rate increased progressively with the increase of varicocele size from grade I to grade III in all groups. The overall incidence of postoperative complications was significantly higher among patients with open surgery. Postoperative spermiogram showed a significant increase in the density and motility and a significant reduction in the percentage of abnormal forms in all groups. The pregnancy rate was approximately similar in all groups. CONCLUSIONS: First, sclerotherapy is best used for isolated left-sided varicoceles. Second, laparoscopy is the treatment of choice for bilateral varicoceles. Finally, open surgery still has a role in isolated right-sided varicoceles and in left-sided cases with failed sclerotherapy.     

Validation of the 36-item short-form Health Survey (Hebrew version) in the adult population of Israel

OBJECTIVES: In the past few years, the SF-36 Health Survey has drawn considerable attention from researchers in non-English-speaking countries. This report contributes to the growing body of literature on this instrument by reporting the results of a national study conducted in Israel. The study examined the psychometric properties of the Hebrew translation based on a sample of the adult population of Israel and evaluated the results from a cross-national perspective. METHODS: The sample included 2,030 adults drawn from the Jewish population, aged 45 to 75 years. The SF-36 Health Survey was administered in face-to-face interviews as part of a broader health study. RESULTS: The pattern of correlations among items and the internal consistency scores pointed to high reliability. Confirmatory factor analysis using the Amos 3.61 program supported the hypothesized factorial structure. Specifically, the items clustered around eight health dimensions, as was found in studies in other societies. Clear and statistically significant differences in the SF-36 Health Survey scores were found among age groups and population groups distinguished by the degree of chronic health problems. CONCLUSIONS: Results of the analysis indicate that the instrument provided an appropriate measure of general health status. The findings clearly indicate that the translation into the Hebrew language and the application of the instrument to a culturally heterogeneous population did not diminish the qualities of the instrument. They also point to certain items that might be modified to reduce problems of synonimity and embeddedness.     

Cancer of the esophagus: outcome of neoadjuvant therapy on surgical morbidity and mortality

Prognosis of oesophageal cancer is poor. There have been phase II-III trials of postoperative chemotherapy with the aim of improving survival. Chemoradiotherapy seems more promising than both chemotherapy and radiotherapy alone. In contrast, better results obtained with chemoradiotherapy were associated with an increase in morbidity and mortality, and finally overall survival was uncommonly improved. It is necessary to implement new multidisciplinary randomised trial.     

Participation of a sialic acid-specific lectin from freshwater prawn Macrobrachium rosenbergii hemocytes in the recognition of non-self cells

Recombinant vaccinia virus (VV) vectors that express the envelope (Env) protein of the human immunodeficiency virus-type 1 (HIV-1) have been previously shown to elicit HIV-specific cytotoxic T-lymphocyte (CTL) and weak antibody responses in non-human primate studies and clinical trials. In first clinical trials, single Env proteins were presented to the immune system by VV recombinants and other vectors, but individuals were not protected against later exposures to heterologous HIV. It is likely that the generation of protective immune responses against diverse HIV will require that vaccines encompass proteins from not just one, but multiple distinct HIV isolates. Here is described the simple construction of numerous new VV, each expressing a unique, truncated, Env protein (VVenv). Mouse experiments were performed to evaluate the ability of these VVenv to elicit immune responses. HIV-1-specific antibodies appeared within one month following one intraperitoneal inoculation of mice with single or mixed VVenv, reaching plateau levels by 4 months. The magnitude of antibody production was poor at the dose of 10(5) p.f.u. VVenv per animal, but improved with increasing doses of VVenv up to 10(7) p.f.u. per animal. The subcutaneous route of VV immunization, previously proven safe in human trials, was also effective for administering VVenv. These results highlight the strengths of recombinant VV constructs as vehicles for the presentation of multiple HIV-1-Env proteins to the naive immune system.     

Cosegregation of the Tnfalpha locus with cardiovascular phenotypes in the F2 generation of a New Zealand genetically hypertensive and Brown Norway cross

1. The association of the Tnfalpha locus with several cardiovascular phenotypes and body mass has been studied in the F2 generation of a reciprocal cross between rats of the New Zealand genetically hypertensive (GH) and the normotensive Brown Norway (BN) strains. In the total F2 population the GH allele of Tnfalpha cosegregated with increased intra-arterial blood pressure (BP) in a recessive manner. A similar but weaker effect was observed for tail BP. 2. An association between genotype and body mass in females with GH grandfathers was also detected. 3. An association between genotype and pulse rate was observed for females. 4. This work supports other evidence pointing to an association of a gene (or genes) on rat chromosome 20 with hypertension.     

Transcellular chloride pathways in ambystoma proximal tubule

The transport mechanisms of Ambystoma proximal tubule that mediate transcellular Cl- absorption linked to Na+ were investigated in isolated perfused tubules using Cl--selective and voltage-recording microelectrodes. In control solutions intracellular activity of Cl- (aiCl) is 11.3 +/- 0.5 mm, the basolateral (V1), apical (V2), and transepithelial (V3) potential differences are -68 +/- 1.2 mV, +62 +/- 1.2 mV and -6.4 +/- 0.3 mV, respectively. When Na+ absorption is decreased by removal of organic substrates from the lumen, aiCl falls by 1.3 +/- 0.3 mm and V2 hyperpolarizes by +11.4 +/- 1.7 mV. Subsequent removal of Na+ from the lumen causes aiCl to fall further by 2.3 +/- 0.4 mm and V2 to hyperpolarize further by +15.3 +/- 2.4 mV. The contribution of transporters and channels to the observed changes of aiCl was examined using ion substitutions and inhibitors. Apical Na/Cl or Na/K/2Cl symport is excluded because bumetanide, furosemide or hydrochlorothiazide have no effect on aiCl. The effects of luminal HCO-3 removal and/or of disulfonic stilbenes argue against the presence of apical Cl-base exchange such as Cl-HCO3 or Cl-OH. The effects of basolateral HCO-3 removal, of basolateral Na+ removal and/or of disulfonic stilbenes are compatible with presence of basolateral Na-independent Cl-base exchange and Na-driven Cl-HCO3 exchange. Several lines of evidence favor conductive Cl- transport across both the apical and basolateral membrane. Addition of the chloride-channel blocker diphenylamine-2-carboxylate to the lumen or bath, increases the aiCl by 2.4 +/- 0.6 mm or 2.9 +/- 1.0 mm respectively. Moreover, following inhibition by DIDS of all anion exchangers in HCO-3-free Ringer, the equilibrium potential for Cl- does not differ from the membrane potential V2. Finally, the logarithmic changes in aiCl in various experimental conditions correlate well with the simultaneous changes in either basolateral or apical membrane potential. These findings strongly support the presence of Cl- channels at the apical and basolateral cell membranes of the proximal tubule.     

Gap junction disappearance in astrocytes and leptomeningeal cells as a consequence of protozoan infection

Trypanosoma cruzi and Toxoplasma gondii are protozoan parasites capable of causing infections of the nervous system. In order to determine effects of infection by these organisms on intercellular communication in the brain, dye coupling and connexin abundance and distribution were examined in leptomeningeal cells and astrocytes infected with T. cruzi or T. gondii. For both cell types infected with either type of protozoan parasite, intercellular diffusion of intracellularly injected Lucifer Yellow was dramatically reduced. Immunocytochemistry with antibodies specific for connexin43 (in astrocytes) or both connexin43 and connexin26 (for leptomeningeal cells) demonstrated that punctate gap junctional staining was much reduced in infected cells, although uninfected neighbors could display normal connexin abundance and distribution. Western blot analyses revealed that connexin43 abundance in both cell types infected with either parasite was similar to that in uninfected cells. Phosphorylation state of connexin43 (inferred from electrophoretic mobility of connexin43 isoforms) was not significantly affected by the infection process. Immunocytochemistry of whole brains from animals acutely infected with either parasite also showed a marked reduction in connexin43 expression. We conclude that infection of both types of brain cells with either protozoan parasite results in a loss of intercellular communication and organized gap junction plaques without affecting expression levels or posttranslational processing of gap junction proteins. Presumably, these changes in gap junction distribution result from altered targeting of the junctional protein to the plasma membrane, and/or from changes in assembly of subunits into functional channels.     

Electrophysiological evidence for dissociable processes contributing to recollection

This paper reviews a number of studies in which we have employed event-related potentials (ERPs) to investigate the cognitive processes which contribute to conscious recollection. Across a range of tasks (including recognition memory, source memory, associative recall and word-stem cued recall) there is evidence for the proposal that recollection involves processes which are both functionally and neurologically dissociable. This evidence takes the form of temporally and topographically dissociable ERP effects, which attain their maximum amplitude when elicited by items that satisfy operational definitions for having been recollected. The ERP effects are interpreted as reflecting retrieval and post-retrieval processes which, we argue, constitute two separate components of recollection as defined within the process dissociation framework of Jacoby and colleagues. The ERP findings suggest that post-retrieval processing is particularly sensitive to task variables, implying that recollection may be neither functionally nor neurologically homogeneous.     

Comparative genomic hybridisation of ductal carcinoma in situ of the breast: identification of regions of DNA amplification and deletion in common with invasive breast carcinoma

Comparative genomic hybridisation has been used to map copy number changes in nine cases of ductal carcinoma in situ of the breast obtained from wax-embedded archive material. A wide variety of abnormalities were detected including gain of regions of 1q, 17q, 19q, 20p and 20q and loss on 13q, 14q, 17p, 16q and 22q. Amplification of areas on 10p, 8q and 20q were also observed. Chromosomal alterations were more frequent in higher grade DCIS and closely resemble those previously detected in invasive breast cancer using the same technique. These data provide strong molecular support for the view that DCIS is a precursor lesion of invasive breast carcinoma.