Thoracic esophageal diverticula. Why is operation necessary?

Human herpesvirus 6 (HHV-6) is a human herpesvirus isolated from patients with various lymphoproliferative disorders and acquired immunodeficiency syndrome (AIDS). The prevalence of HHV-6 infection and its correlation as a cofactor in pathogenicity of HIV infection was investigated in serum samples from 365 healthy volunteers at various age groups, 50 persons at risk for HIV-1 infection, and 90 HIV-1 seropositive individuals. Sera were screened and titrated for antibodies against HHV-6 by a standard indirect immunofluorescence assay on an acetone fixed HHV-6 infected HSB2 cells. The data show high prevalence of HHV-6 in Thailand (71.7%) and the infection is acquired early in life. Prevalence of anti-HHV-6 IgG antibodies was not strikingly different among people at risk for HIV infection, asymptomatic HIV-1 infected cases, and aged-matched controls with low risk for HIV-1 infection. The AIDS cases showed high titers of anti-HHV-6 IgG antibody and high rates for presence of anti-HHV-6 IgM antibody (33.3%) which suggests higher prevalence of HHV-6 infection by either reactivation of an earlier HHV-6 infection or a new primary infection.     

A two-dimensional hot carrier injector for electron waveguide structures

The current-voltage characteristics for a constriction in a quantum waveguide channel are calculated. The constriction forms an effective barrier which can be employed as a tunneling injector. We find that such a structure may be useful in providing high-energy electrons in a single mode of the waveguide. We also examine the current in the far-from-linear response regime. Away from the linear region the current through the constriction saturates and the conductance falls to zero.     

Robinson anterior cervical discectomy and arthrodesis for cervical radiculopathy. Long-term follow-up of one hundred and twenty-two patients

We evaluated the results of the Robinson method of anterior cervical discectomy and arthrodesis with use of autogenous iliac-crest bone graft, at one to four levels, in 122 patients who had cervical radiculopathy. A one-level procedure was done in sixty-two of the 122 patients; a two-level procedure, in forty-eight; a three-level procedure, in eleven; and a four-level procedure, in one. The average duration of clinical and roentgenographic follow-up was six years (range, two to fifteen years). The average age was fifty years (range, twenty-five to seventy-eight years). Preoperatively, 118 patients had pain in the arm, fifty-five had weakness of one or more motor roots, and seventy-seven had sensory loss. At the time of follow-up, eighty-one patients had no pain in the neck, twenty-six had mild pain in the neck, nine had moderate pain in the neck, four had mild radicular pain, and two had a combination of mild radicular pain and moderate pain in the neck. One hundred and eight patients had no functional impairment, and fourteen had a slight limitation of function during the activities of daily living. Nine of eleven patients who had symptoms related to a change at one level cephalad or caudad to the site of a previous arthrodesis had another operative procedure. Lateral roentgenograms of the cervical spine, made in flexion and extension, showed a pseudarthrosis at twenty-four of 195 operatively treated segments. Sixteen of the patients who had a pseudarthrosis were symptomatic, but only four had sufficient pain to warrant revision. The risk of pseudarthrosis was significantly greater after a multiple-level arthrodesis than after a single-level arthrodesis (p < 0.01). At the time of the most recent follow-up, fifty-three of the fifty-five patients who had had a motor deficit had had a complete recovery, and the two remaining patients had had a partial recovery. Seventy-one of the seventy-seven patients who had had a sensory loss had regained sensation. None of the patients had an increased neurological deficit postoperatively. Our results suggest that the Robinson anterior cervical discectomy and arthrodesis with an autogenous iliac-crest bone graft for cervical radiculopathy is a safe procedure that can relieve pain and lead to resolution of neurological deficits in a high percentage of patients.     

Growth, reproductive performance, mammary development, and milk production of beef heifers as influenced by prepubertal dietary energy and administration of bovine somatotropin

Three trials with 156 crossbred heifers were used to determine the effects of dietary energy and bovine somatotropin administration on subsequent heifer productivity. In Trial 1, heifer calves were weaned from their dams (n = 28; 113 +/- 13 d of age) and assigned to a 2 x 2 factorial arrangement of moderate (MDE) or high dietary energy (HDE) and injections of vehicle (VEH) or 250 mg of bovine somatotropin (bST) every 14 d. Heifer calves in Trial 2 (n = 28; 123 +/- 20 d of age) and Trial 3 (n = 100; 134 +/- 22 d of age) nursed their dams while grazing pasture and received no creep feed (MDE) or ad libitum access to creep feed (HDE) and received VEH or bST as in Trial 1. Treatments were administered for 112 d and heifers within trial were managed alike after that time. There were no dietary treatment x bST treatment interactions for any of the variables analyzed (P > .05). Dietary energy did not affect daily gain in Trial 1; however, heifers receiving HDE in Trials 2 and 3 had greater weight, hip height growth, and fat thickness (P < .01) by the end of the treatment period. Treatment with bST increased gain in Trials 1 and 2 (P < .01) but did not affect growth in Trial 3. There were trends in all trials for HDE to reduce age at puberty (P < .15), but there were no consistent effects of bST on reproductive measures. Mammary gland composition and milk production were unaffected by treatment in Trial 1. In Trial 2, HDE decreased subsequent milk production, calf weaning weight, and mammary dry fat free tissue and DNA (P < .05). Treatment with bST in Trial 3 tended (P = .08) to result in greater milk production and increased calf weaning weights (P < .05). We conclude that bST treatment may enhance growth with no effect on reproduction. Treatment with bST did not overcome deleterious effects of HDE on milk production but may play an important role in mammogenesis.     

Phospholipids of Lactobacillus spp

Lactobacillus phospholipid molecular species were analyzed by mass spectrometry. Prominent anions were consistent with presence of the phosphatidylglycerols PG(37:2), PG(36:2), PG(35:1), PG(34:1), and PG(33:1). Diglycosyldiacylglycerol molecular species were also observed, although nitrogen-containing phospholipids were absent. An anion of m/z 759 was derived from an apparently novel type of lipid.     

Impaired human responses to tetanus toxoid in vitamin A-deficient SCID mice reconstituted with human peripheral blood lymphocytes

Vitamin A deficiency is associated with increased childhood morbidity and mortality from respiratory and diarrheal diseases. In order to evaluate the effect of vitamin A on human antibody responses, we developed a vitamin A-deficient severe combined immunodeficient (SCID) mouse model. Vitamin A-deficient mice were produced by depriving them of vitamin A at day 7 of gestation. Mice were reconstituted with human peripheral blood lymphocytes (huPBL) from tetanus toxoid immune donors at 6 weeks of age and immunized with tetanus toxoid at 6 and 8 weeks of age. Secondary human antibody responses were determined 10 days later. The geometric mean human anti-tetanus toxoid immunoglobulin G concentrations were 3.75 micrograms/ml for the deficient mice and 148 micrograms/ml for controls (P = 0.0005). Vitamin A-deficient mice had only a 2.9-fold increase in human anti-tetanus toxoid antibody compared with a 74-fold increase in controls (P < 0.01). Supplementation with vitamin A prior to reconstitution restored human antibody responses to normal. These data suggest that vitamin A deficiency impairs human antibody responses. We speculate that impaired responses could increase susceptibility to certain infections. Furthermore, we propose that effects of other nutritional deficiencies on the human immune system could be evaluated in the SCID-huPBL model.     

Role of sex, gender roles, and attraction in predicting emergent leaders.

Examined the influence of sex, gender role characteristics, and interpersonal attractiveness on the selection of emergent leaders. Data were collected on 2 occasions from 122 subjects in 28 task groups performing "sex neutral" tasks for valued rewards over many weeks of interaction. Results showed no significant difference in the proportion of men and women to emerge as leaders through intragroup sociometric choice. Regardless of sex, group members with masculine gender role characteristics emerged as leaders significantly more than those with feminine, androgynous, or undifferentiated gender role characteristics. Emergent leaders received significantly higher interpersonal attractiveness ratings than nonleaders within groups. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How potassium affects the activity of the molecular chaperone Hsc70. I. Potassium is required for optimal ATPase activity

Several functions of the 70-kilodalton heat shock cognate protein (Hsc70), such as peptide binding/release and clathrin uncoating, have been shown to require potassium ions. We have examined the effect of monovalent ions on the ATPase activity of Hsc70. The steady-state ATPase activities of Hsc70 and its amino-terminal 44-kDa ATPase fragment are minimal in the absence of K+ and reach a maximum at approximately 0.1 M [K+]. Activation of the ATPase turnover correlates with the ionic radii of monovalent ions; those that are at least 0.3 A smaller (Na+ and Li+) or larger (Cs+) than K+ show negligible activation, whereas ions with radii differing only approximately 0.1 A from that of K+ (NH4+ and Rb+) activate to approximately half the turnover rate observed with K+. Single turnover experiments with Hsc70 demonstrate that ATP hydrolysis is 5-fold slower with Na+ than with K+. The equilibrium binding of ADP or ATP to Hsc70 is unperturbed when K+ is replaced with Na+. These results are consistent with a role for monovalent ions as specific cofactors in the enzymatic hydrolysis of ATP.     

Theoretical Study of Molecular Quantum-Dot Cellular Automata

We present an ab initio quantum chemistry study of {(η⁵-C₅H₅)Fe(η⁵-C₅H₄)}₄(η⁴-C₄)Co(η⁵-C₅H₅)²⁺, a molecular candidate for quantum-dot cellular automata (QCA) which has been synthesized and characterized recently. Our studies support the experimental interpretation that this molecule has a bistable electronic state, and that binary information can be encoded in the molecular charge configuration. We show that when molecules are properly arranged, one molecule can be switched by the Coulomb interaction produced by a neighboring molecule. Our studies also show this molecule is error-tolerant when the four-fold symmetry is broken by a C–C single-bond distortion.