National survey of blindness and low vision in Lebanon

Here we report a case that presented with sudden onset of neurological symptoms and was treated with ganciclovir. Polymerase chain reaction analysis for human herpes virus-6 (HHV-6) from his cerebrospinal fluid was later found to be positive. He subsequently recovered with minimal residual neurological symptoms. Encephalitis secondary to this virus may be more common than previously thought in patients undergoing bone marrow transplantation. This condition should be considered in the differential diagnosis of sudden onset neurological symptoms after bone marrow transplantation.     

Impact of Elaboration on Socially Desirable Responding and the Validity of Biodata Measures.

The current study investigated the impact of requiring respondents to elaborate on their answers to a biodata measure on mean scores, the validity of the biodata item composites, subgroup mean differences, and correlations with social desirability. Results of this study indicate that elaborated responses result in scores that are much lower than nonelaborated responses to the same items by an independent sample. Despite the lower mean score on elaborated items, it does not appear that elaboration affects the size of the correlation between social desirability and responses to biodata items or that it affects criterion-related validity or subgroup mean differences in a practically significant way. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A case of paraquat poisoning and subsequent fatality presenting to an emergency department

Paraquat (1,1'-dimethyl-4,4'-dipyridylium) is an herbicide associated with both accidental and intentional ingestion, leading to severe and often fatal toxicity. Prognosis is largely dependent on the amount of paraquat absorbed. Rapid identification of the symptoms of paraquat toxicity (burns or ulceration at the site of ingestion or injection, acute respiratory distress, and renal failure) can facilitate early treatment intervention to limit absorption. We report a case of a 71-year-old man with a suicidal ingestion of paraquat 2 days prior to presentation. Serum paraquat levels, time elapsed since ingestion, and clinical symptoms all indicated poor prognosis. The patient developed severe respiratory distress and progressive renal failure, and died 6 days after admission to the hospital.     

Development of calcium signalling mechanisms during maturation of human oocytes

Sperm-induced Ca2+ signals mediate the events of oocyte activation at fertilization. In this study, the development of mechanisms involved in the generation of Ca2+ signals in human oocytes was investigated. The thiol reagent, thimerosal, which induces oscillations of intracellular Ca2+ ([Ca2+]i) similar to those seen during fertilization, was used to mobilize Ca2+ in in-vivo matured, immature and in-vitro matured human oocytes. There was an increase in the sensitivity to thimerosal during maturation of human oocytes, with oocytes from small antral follicles being relatively insensitive, compared with those from luteinized follicles, which displayed a large spike followed by sustained oscillations in [Ca2+]i. These oscillations were inhibited by caffeine which suggests that they were mediated by the inositol trisphosphate receptor Ca2+ release system. When immature oocytes were cultured in vitro they acquired the capacity to undergo a single large spike in [Ca2+]i, however, subsequent sustained oscillations were not observed, indicating that these oocytes failed to develop fully competent Ca2+ signalling mechanisms during culture in vitro. This finding may be a key factor in the poor developmental competence of in-vitro matured human oocytes.     

Particle-bombardment-mediated DNA vaccination with rotavirus VP4 or VP7 induces high levels of serum rotavirus IgG but fails to protect mice against challenge

We recently reported that epidermal immunization using the PowderJet particle delivery device with plasmid vector pcDNA1/EDIM6 encoding rotavirus VP6 of murine strain EDIM induced high levels of serum rotavirus IgG but failed to protect mice against EDIM infection (Choi, A. H., Knowlton, D. R., McNeal, M. M., and Ward, R. L. (1997) Virology 232, 129-138.). This was extended to determine whether pcDNA1/EDIM4 or pcDNA1/EDIM7, which encode either rotavirus VP4 or VP7, the rotavirus neutralization proteins, could also induce rotavirus-specific antibody responses and if these responses resulted in protection. Titers of rotavirus serum IgG increased with the first dose in mice immunized with pcDNA1/EDIM7, but little or no serum rotavirus IgG was detected in mice immunized with pcDNA1/EDIM4. In vitro assays with these plasmids in rabbit reticulocyte lysates showed that VP4 was expressed but the amount was considerably lower than VP6 or VP7. To improve expression of VP4 and induction of rotavirus-specific humoral responses, the coding region of VP4 was cloned into the high-expression plasmid WRG7054 as a fusion protein containing the 22-amino-acid secretory signal peptide of tissue plasminogen activator (tPA) at its N terminus. In vitro expression of tPA::VP4 was significantly higher than unmodified VP4, and mice inoculated with WRG7054/EDIM4 generated high titers of rotavirus IgG. The coding sequence of VP7 without the first 162 nucleotides was also cloned into WRG7054, but no difference was observed between titers of serum rotavirus IgG in mice immunized with this plasmid (WRG7054/EDIM7Delta1-162) and pcDNA1/EDIM7. The rotavirus-specific IgG titers in all immune sera were predominantly IgG1 indicating induction of Th 2-type responses. None of the mice immunized with any of the VP4 or VP7 plasmids developed serum or fecal rotavirus IgA or neutralizing antibody to EDIM. When immunized mice were challenged with EDIM virus, there was no significant reduction in viral shedding relative to unimmunized controls. Therefore epidermal immunization with VP4 or VP7 alone elicited rotavirus IgG responses but did not protect against homologous rotavirus challenge.     

Evolution of peptides that modulate the spectral qualities of bound, small-molecule fluorophores

BACKGROUND: Fluorophore dyes are used extensively in biomedical research to sensitively assay cellular constituents and physiology. We have created, as proof of principle, fluorophore dye binding peptides that could have applications in fluorescent dye-based approaches in vitro and in vivo. RESULTS: A panel of Texas red, Rhodamine red, Oregon green 514 and fluorescein binding peptides, termed here 'fluorettes', was selected via biopanning of a combinatorial library of 12-mer peptides fused to a minor coat pIII protein of the filamentous bacteriophage M13. The 'best' fluorette sequences from each of the groups were subjected to further mutagenesis, followed by a second biopanning to select a new generation of improved fluorettes. Phage were selected that had higher avidity for each fluorophore except Rhodamine red. Of these, peptides were characterized that could specifically and with high affinity bind at least one dye, Texas red, in solution. In addition, the binding of certain peptides to Texas red shifted the peak excitation and/or the emission spectra of the bound dye. CONCLUSIONS: Peptides in the context of phage display could readily be selected that could bind to small-molecule fluorophores. The affinities of selected mutant fluorettes could be increased by mutation and further selection. Only a subset of the free peptides could bind free dyes in solution, suggesting that phage context contributed to the selection and ability of certain peptidic regions to independently bind the dyes. Future screens might lead to the creation of other dye-binding peptides with novel characteristics or Texas red derivatives with cross-linking substituents might be designed to increase the utility of the system.     

Establishment and neurite outgrowth properties of neonatal and adult rat olfactory bulb glial cell lines

Two glial cell types surround olfactory axons and glomeruli in the olfactory bulb (OB) and may influence synapse development and regeneration. OB astrocytes resemble type-1 astrocytes, and OB ensheathing cells resemble non-myelinating Schwann cells. We have produced clonal OB astrocyte and ensheathing cell lines from rat neonatal and adult OB cultures by SV40 large T antigen transduction. These cell lines have been characterized by morphology, growth characteristics, immunophenotype, and ability to promote neurite outgrowth in vitro. Neonatal and adult ensheathing cell lines were found to support higher neurite outgrowth than OB astrocyte lines. Neonatal OB astrocyte lines were of two types, high and low outgrowth support. The low support astrocyte lines express J1 and a chondroitin sulfate-containing proteoglycan as do astrocytes encircling the neonatal glomeruli in vivo. The adult OB astrocyte cell lines supported lower levels of outgrowth than adult ensheathing cell lines. These results are consistent with a positive role for ensheathing cells in OB synapse regeneration, in vivo. Further, based on our results, we hypothesize that ensheathing cells and high-outgrowth astrocytes facilitate axon growth in vivo, while low outgrowth astrocytes inhibit axon growth and may facilitate glomerulus formation.     

Effects of fatty acid oxidation on glucose utilization by isolated hepatocytes

We have studied the inhibitory action of long- and short-chain fatty acids on hepatic glucose utilization in hepatocytes isolated from fasted rats. The rates of hepatic glucose phosphorylation and glycolysis were determined from the tritiated products of [2-3H] and [6-3H]glucose metabolism, respectively. The difference between these was taken as an estimate of the 'cycling' between glucose and glucose-6-phosphate. In the presence of 40 mM glucose this cycling was estimated at 0.68 mumol/min/g wet wt. Glucose phosphorylation was unaffected during palmitate and hexanoate oxidation to ketone bodies but glycolysis was inhibited. The rate of glucose cycling was increased during this phase to 1.25 mumol/min/g. Following the complete metabolism of the fatty acids, glycolysis was reinstated and cycling rates returned to control levels. Hepatic glucose cycling appears to be an important component of the glucose/fatty acid cycle.     

Use of a subcutaneous glucose sensor to detect decreases in glucose concentration prior to observation in blood

The development of a hypoglycemic alarm system using a subcutaneous glucose sensor implies that a decrease in blood glucose is rapidly followed by a decrease in the signal generated by the sensor. In a first set of experiments the linearity and the kinetics of the response of sensors implanted in the subcutaneous tissue of normal rats were investigated during a progressive increase in plasma glucose concentration: the sensitivities determined between 5 and 10 mM and between 10 and 15 mM were not significantly different, and a 5-10 min delay in the sensor's response was observed. In a second set of experiments, performed in diabetic rats, the kinetics of the decrease in subcutaneous glucose concentration following insulin administration was monitored during a decrease in plasma glucose level, from 15 to 3 mmol/L. During the 20 first min following insulin administration, the sensor monitored glucose concentration in subcutaneous tissue with no lag time. Subsequently, the decrease in the estimation of subcutaneous glucose concentration preceded that of plasma glucose. This phenomenon was not observed when the same sensors were investigated in vitro during a similar decrease in glucose concentration and may be due to a mechanism occurring in vivo, such as the effect of insulin on glucose transfer from the interstitial space to the cells surrounding the sensor. It reinforces the interest of the use of implantable glucose sensors as a part of a hypoglycemic alarm.