Isolation and characterization of toxic proteins from the venom of the Venezuelan scorpion Tityus discrepans (Karsch)

Four toxic, electrophoretically homogeneous proteins were isolated by ion-exchange chromatography on CM-cellulose-52 from the venom of the scorpion Tityus discrepans (range North Central Venezuela), named TdIV, TdV, TdVIII and TdIX. Component TdVIII, with 56 amino acid residues and mol. wt 6140 was the most toxic by i.p. injections into mice and had an intracisternal LD50 of 7.9 micrograms protein/kg body weight. Amino acid compositions of components TdIV and TdV were very similar, suggesting that they could be highly homologous proteins, although presumably contaminated one by the other. A fifth component, named TdIII, non-toxic by i.p. injections, was also isolated in homogeneous form. The i.v. and intracisternal LD50 values of the whole T. discrepans venom were 2.5 mg/kg and 16.0 micrograms/kg, respectively.     

Induction of non-specific airway hyperreactivity by potassium channel blockade in rat isolated trachea.

1. The exposure of rat isolated tracheal segment to the K(+)-channel inhibitor tetraethylammonium (TEA, 10 mM) for a period of 10-15 min generally produced little or no contractile response. 2. Cooling (10 C) provocation alone usually produced small (10 +/- 3% acetylcholine maximum) contractile responses. 3. In the presence of TEA (10 mM, 10-15 min exposure), rat trachea exhibited airway hyperreactivity to acetylcholine, 5-hydroxytryptamine (5-HT) and cooling. It also increased the peak tension induced by 5-HT. 4. TEA-induced airway hyperreactivity to cooling was significantly inhibited in Ca2(+)-free Krebs solution suggesting an important role for extracellular Ca2+ influx. 5. We conclude that the blockade of potassium channels with TEA induces non-specific airway hyperreactivity to cooling, 5-HT and acetylcholine in rat isolated tracheal segments.     

Interaction of Felbamate with [H]DCKA-Labeled Strychnine-Insensitive Glycine Receptors in Human Postmortem Brain

The dicarbamate felbamate has been shown to be capable of competing for the binding of 5,7-[³H]dichlorokynurenic acid ([³H]DCKA) to strychnine-insensitive glycine receptors in sections of human postmortem brain. The IC₅₀ for this interaction was 305.8 μM and the inhibition was complete at 1 mM. Autoradiographic localization of [³H]DCKA binding revealed many regions of human brain in which strychnine-insensitive glycine receptors are manifest. The specific binding in most of these areas was markedly reduced in the presence of 625 μM felbamate. In many regions, [³H]DCKA binding was reduced to background in the presence of felbamate, but some areas retained binding by as much as 41% (i.e., the CA2 region of the hippocampus). This is in contrast to the binding of [³H]DCKA in the presence of carbamazepine, phenytoin, or valproic acid. The binding of the glycine receptor antagonist was not affected by any of these latter agents to the same degree as felbamate. Strychnine-insensitive glycine receptors represent a site of action of felbamate in the human brain.     

Serum adiponectin concentrations and tissue expression of adiponectin receptors are reduced in patients with prostate cancer: a case control study.

PURPOSE: Adiponectin, an adipocyte-secreted hormone with insulin-sensitizing effects, has been inversely associated with several hormonally dependent malignancies, including breast, endometrial, and colorectal cancer. Few studies have examined serum adiponectin in relation to prostate cancer, and expression of adiponectin receptors has previously not been assessed in prostate tumors. EXPERIMENTAL DESIGN: We collected plasma samples and covariate data in the context of a case-control study of 300 Greek men, including 75 prostate cancer cases, 75 patients with benign prostatic hyperplasia (BPH), and 150 healthy controls. Prostate tissue samples were taken from 72 cases and 27 noncases and examined for relative expression of adiponectin receptors AdipoR1 and AdipoR2 using immunohistochemistry. RESULTS: Prostate cancer patients had significantly lower plasma adiponectin concentrations as compared with men with BPH and healthy controls (7.4 +/- 5.0 versus 11.5 +/- 6.4 and 12.8 +/- 8.0 ng/mL, respectively). Men in the top two quartiles of adiponectin had a 71% to 73% reduced risk of prostate cancer as compared with men in the lowest quartile after adjusting for age, body mass index, and additional potential confounders. We found no similar relationship between adiponectin and risk of BPH. Results from immunohistochemistry experiments show weaker expression of adiponectin receptors AdipoR1 and AdipoR2 in cancerous versus healthy prostate tissue. CONCLUSIONS: Higher serum adiponectin is associated with a marked reduction in risk of prostate cancer, but not BPH, independently of other risk factors. Malignant prostate tissue samples have reduced expression of adiponectin receptors as compared with benign prostate tissue. These results support a role for adiponectin in the pathogenesis of prostate cancer.     

The role of computerized order sets in pediatric inpatient asthma treatment

Condition-specific order sets within computerized physician order entry (CPOE) systems are designed to decrease unnecessary practice variation and to promote evidence-based practice. This study quantitatively assessed the relationship between use of a computerized order set and processes of care in inpatient pediatric asthma treatment, and qualitatively assessed user attitudes toward order set use. The study population included 790 patients with a primary diagnosis of asthma admitted to Columbus Children's Hospital between November 1, 2001 and November 30, 2003. Rates of systemic corticosteroid (SCS) use, metered-dose inhaler use, and pulse oximetry (PulseOx) were calculated for three patient groups: those admitted prior to order set implementation ('pre-set'); those admitted after implementation but without the order set used ('no set'); and those admitted after implementation with the order set used ('set'). Financial measures of length of stay, total charges, and pharmacy charges were also calculated. Focus groups exploring attitudes about order sets were held with physician users of order sets. Order set patients were significantly more likely to receive SCS and PulseOx than 'pre-set' and 'no set' patients. 'No set' patients did not differ significantly from 'pre-set' patients. No significant differences were found in financial measures. Results from focus groups suggested that order set use would be optimized by promoting order set awareness and maximizing order set quality. These results give further credence to policy-makers' calls for expanded use of CPOE systems with condition-specific order sets to facilitate provision of evidence-based care.     

Expansion of CD8+ cytotoxic T cells in vitro and in vivo using MHC class I tetramers.

BACKGROUND: The expansion of cytotoxic CD8+ T lymphocytes (CTLs) which recognize peptide epitopes of tumour or viral origin has been a major aim of immunotherapy research for the past decade. Alongside the established dendritic cell-based methods, more recent approaches using recombinant MHC class I peptide complexes have been developed. METHODS: In this study we have explored the potential of a simplified system using soluble streptavidin-linked MHC class I tetramers to expand antigen-specific CTLs in vitro and in vivo. RESULTS: In vitro tetramer-mediated expansion of CD8+ CTLs recognizing HLA-2/Melan-A and HLA-A2/Gag complexes was demonstrated with PBMCs from healthy donors or HIV+ donors, respectively. With 3 weekly rounds of tetramer stimulation, cell numbers expanded 100-fold from 0.05 to 5.0%. The lytic function of HLA-A2/Melan-A-expanded cells was demonstrated in 51Cr release assays by specific killing of T2 cells pulsed with Melan-A, but not other peptides. Similarly, murine CD8+ T cells specific for the HY epitope H2-Db/Uty could be expanded in vitro over a wide range of tetramer concentrations (0.008-1.0 microg/ml), with a single exposure producing substantial T cell expansion from 0.11 to 36%. Intraperitoneal administration of H2-Db/Uty tetramers to primed C57BL/6 mice produced over 5-fold expansion of Db/Uty-specific CTL in vivo. CONCLUSION: The results in this paper demonstrate that simple, multimeric MHC complexes may be of value in expanding CTLs in vitro for adoptive immunotherapy and also potentially in vivo. Further studies will be necessary to clarify the optimum protocols and schedules of administration for T cell expansion using recombinant MHC multimers.     

Influence of Obstructive Jaundice on Jejunal Absorption of Glucose, Electrolytes, and Vitamin A in Rats

Jejunal absorption of glucose, electrolytes, andvitamin A was investigated in rats. A Tyrode solutioncontaining glucose, sodium, and potassium inconcentrations two and four times higher than usual was infused through the jejunal loops of jaundicedand control rats during 40 min. The glucose values inthe influx and effluent were not different during theexperiment time. However, the concentrations of sodium and potassium of the effluent decreasedwith concentrations twice normal. The osmotic pressureof the effluent was directly related to the electrolyticconcentration. When the perfusate fluid was four times higher, the differences between shamand jaundiced groups remained unchanged. The osmoticpressure means of the jaundiced group decreased duringthe experimental time. The absorption of vitamin A increased during the 40-min experiment timein the control rats. On the other hand, vitamin Aconcentration in the perfused lumen of the jaundicedgroup did not change over the time. These data indicate that obstructive jaundice has little influenceon glucose and electrolytes absorption, while vitamin Ais impaired by this condition.