Early Single-Photon Emission Computed Tomography in Mild Head Trauma

Although computed tomography (CT) and magnetic resonance imaging scans often appear normal after mild head trauma, many patients experience attentional or other cognitive disturbances that are difficult to quantify by neuropsychological testing in the absence of a premorbid profile. Within 2 days of mild head trauma, 14 patients with normal-appearing brain CTs were studied with single-photon emission computed tomography (SPECT). They were compared to 15 normal control subjects and to 12 patients with mild human immunodeficiency virus (HlV) encephalopathy. Ten of 14 head trauma patients were separated from the normal control subjects by both independent readers, blinded to the clinical diagnosis. None of the SPECT results from normal control subjects were ‘read’ as trauma. Trauma could not be differentiated from HlV encephalopathy. The observed percentage agreement between raters was 0.83 (K = 0.72). SPECT is more sensitive than CT in detecting brain injury after mild head trauma.     

Preparation and characterization of monoclonal antibodies to rotavirus

By utilizing a strain of cultivable simian rotavirus (SA-11) as an immunizing antigen, we prepared 4 clones of mouse-mouse hybridoma, namely C127, C139, C172, and C214 which secreted monoclonal antibodies against the immunogen itself, SA-11 and also against other group A strains such as Wa and S2. Western blot analyses revealed that all of these antibodies are directed against VP6, a 42 kDa major inner capsid protein of group A rotavirus. Competitive experiments suggested that C127, C172 and C214 recognized three distinct epitopes on VP6, while C139 appeared to react with an epitope at or near the same epitope recognized by C172. We developed a two-step ELISA with excellent sensitivity and specificity for rotavirus detection by utilizing C127 and/or C214 as a capture antibody and rabbit anti-rotavirus conjugated with horseradish peroxidase as a probe. Also, when both monoclonal C127 capture antibody and polyclonal rabbit anti-rotavirus-HRP were incubated with rotavirus simultaneously in a one-step assay, equivalent sensitivity and specificity were observed. The data show that these generated anti-rotavirus antibodies can be utilized effectively as reagents for the detection of human rotaviruses in stool specimens.     

An increase in the number of recombinant molecules and other effects of the simultaneous allotype suppression of trans-chromosomal a VH and n Cmu Ig gene products

The concomitant effects of trans-chromosomal allotype suppression of both an a VH and an n Cmu locus allotype in multiheterozygous rabbits were investigated. For example of the expression of the a2 VH and n81 Cmu allotypes were suppressed in a multiheterozygous rabbit having the a1 chi-y-n81de12,15f73g74/a2 chi 32y33n80de12.14f69g77 genotype. This trans-chromosomal allotype suppression led to the concomitant suppression of other CH allotypes in the same parental haplotype as the suppressed-n81 allotype (i.e. the e15, f73 and g74 allotype) and the partial suppression of the a1 VH allotype (from the normal level of 70% of the total Ig to 10%), and also led to compensation by other VH allotypes from the same parental haplotype as the suppressed-a2 allotype (i.e. the x32 and y33 allotypes). The x32 and y33 allotypes were expressed on Ig molecules with the CH allotypes coded by the same haplotype (i.e. the cis molecules). In a further analysis of the IgG molecules having the partially-suppressed-a1 allotype, one-half (5%) of these molecules were trans-chromosomal recombinant molecules (i.e. a1e14 IgG) and the other half (5%) were cis-chromosomal molecules (i.e. a1e15 IgG). The trans-chromosomal a1e14 IgG molecules probably were derived from the expansion of a limited number of lymphoid clones that normally produce only 1.5% trans-chromosomal recombinant molecules. The cis-chromosomal a1e15 IgG molecules were probably derived either from lymphoid clones that survived the suppression by the anti-n81 Ab, or from lymphoid clones that bore a different subclass of IgM (i.e. n-negative IgM).     

Interactions of the enantiomers of 3-O-methyldobutamine with α- and β-adrenoceptors in vitro

Summary The enantiomers of 3-O-methyldobutamine, a metabolite of dobutamine, were evaluated for their - and -adrenoceptor mediated effects in vitro in a variety of isolated organs and in radioligand binding studies. Neither enantiomer of 3-O-methyldobutamine possessed ₁-adrenoceptor agonist activity in isolated guinea pig aorta. However, both enantiomers of 3-O-methyldobutamine were competitive ₁-adrenoceptor antagonists, with the (+)-enantiomer being approximately 10-fold more potent than the (-)-enantiomer as assessed either in guinea pig aorta or by displacement of ³H-prazosin binding from ₁-adrenoceptors in rat cerebral cortex. The ₁-adrenoceptor blocking activity of (+)-3-O-methyldobutamine was relatively potent and corresponded to a pA₂ of 7.33 in guinea pig aorta and a-log K _i of 7.72 in radioligand binding studies. Neither enantiomer of 3-O-methyldobutamine possessed ₂-adrenoceptor agonist activity in field-stimulated guinea pig ileum. Although (+)-3-O-methyldobutamine weakly inhibited the twitch response in field-stimulated guinea pig ileum, the response was not blocked by the selective ₂-adrenoceptor antagonist, yohimbine, and was found to result from weak anticholinergic activity (pA₂=5.06). Neither enantiomer of 3-O-methyldobutamine possessed ₁-adrenoceptor agonist activity in guinea pig atria, however the (+)-enantiomer was a weak noncompetitive antagonist at ₁-adrenoceptors. In contrast, both enantiomers of 3-O-methyldobutamine were weak ₂-adrenoceptor agonists in rat uterus, however these weak effects were not highly stereoselective, which was also confirmed in radioligand binding studies. The results of the present study indicate that 3-O-methyldobutamine is a potent and highly selective ₁-adrenoceptor antagonist, with minimal activity at ₂-, ₁- and ₂-adrenoceptors. It is hypothesized that the potent ₁-adrenoceptor antagonist activity of 3-O-methyldobutamine, which resides predominantly in the (+)-enantiomer, may play a role in the hemodynamic effects of dobutamine, by contributing, in part, to the decrease in total peripheral vascular resistance observed following administration of dobutamine.     

Plasma selenium levels and risk of hepatocellular carcinoma among men with chronic hepatitis virus infection.

Both experimental and epidemiologic studies have linked a low dietary intake of selenium with an increased risk of cancer. The authors examined the association between plasma selenium levels and risk of hepatocellular carcinoma (HCC) among chronic carriers of hepatitis B and/or C virus in a cohort of 7,342 men in Taiwan who were recruited by personal interview and blood draw during 1988-1992. After these men were followed up for an average of 5.3 years, selenium levels in the stored plasma were measured by using hydride atomic absorption spectrometry for 69 incident HCC cases who were positive for hepatitis B surface antigen (HBsAg) and/or antibodies against hepatitis C virus (mostly HBsAg positive) and 139 matched, healthy controls who were HBsAg positive. Mean selenium levels were significantly lower in the HCC cases than in the HBsAg-positive controls (p = 0.01). Adjusted odds ratios of HCC for subjects in increasing quintiles of plasma selenium were 1.00, 0.52, 0.32, 0.19, and 0.62, respectively. The inverse association between plasma selenium levels and HCC was most striking among cigarette smokers and among subjects with low plasma levels of retinol or various carotenoids. There was no clear evidence for an interaction between selenium and alpha-tocopherol in relation to HCC risk.     

Isoeugenolol: a selective beta1-adrenergic antagonist with tracheal and vascular smooth muscle relaxant properties.

Isoeugenolol (1.0, 3.0, 5.0 mg/kg, i.v.) produced a dose-dependent bradycardia and a decrease in blood pressure in anesthetized Wistar rats. Isoeugenolol inhibited the tachycardia effects induced by (-)isoproterenol, but had no blocking effect on the arterial pressor responses induced by (-)phenylephrine. In isolated guinea pig tissues, isoeugenolol antagonized (-)isoproterenol-induced positive inotropic and chronotropic effects on the atria and tracheal relaxations in a concentration-dependent manner. The apparent pA2 values for isoeugenolol on right atria, left atria and trachea were 7.63+/-0.03, 7.89+/-0.12 and 6.12+/-0.05, respectively, indicating that isoeugenolol was a highly selective beta1-adrenoceptor blocker. On the other hand, isoeugenolol produced a mild direct cardiac depression at high concentration and was without intrinsic sympathomimetic activity (ISA). In isolated rat thoracic aorta, isoeugenolol relaxed more potently the contractions induced by (-)phenylephrine (10 microM) and 5-HT (10 microM) than those by high K+ (75 mM). In isolated guinea pig trachea, isoeugenolol attenuated the carbachol (1 microM)-con-tracted trachea more significantly than those contracted with high K+. Furthermore, the binding characteristics of isoeugenolol and various beta-adrenoceptor antagonists were evaluated in [3H]CGP-12177 binding to rat ventricle, lung and interscapular brown adipose tissue (IBAT) membranes. The -log IC50 values of isoeugenolol for predominate beta1-, beta2- and beta3-adrenergic receptor sites were 5.82+/-0.09, 4.74+/-0.05 and 4.73+/-0.12, respectively. In conclusion, isoeugenolol was found to be a highly selective beta1-adrenoceptor antagonist with tracheal and vascular smooth muscle relaxant activities, but was devoid of alpha-adrenoceptor-blocking action.