Detection of human T-lymphotropic virus (HTLV) tax sequences in New York City blood donors seronegative for HTLV types 1 and 2

A potential public health concern is the reported detection of the human T-lymphotropic virus (HTLV) tax gene in the lymphocytes of up to 11% of a low-risk group of New York City blood donors (NYBD). This study aimed to independently confirm the prevalence of HTLV tax sequences in 293 NYBD. All NYBD tested negative for antibodies to HTLV types 1 and 2 and HTLV Tax. HTLV tax sequences were not detected in the NYBD lymphocytes. These data demonstrate the lack of HTLV-1 tax in this group of NYBD at low risk for HTLV infection.     

Characterization of a major neutralization domain of Ross river virus using anti-viral and anti-peptide antibodies.

The E2 glycoprotein of the alphavirus Ross River virus (RRV) contains three defined neutralization epitopes (a, b1 and b2) with determinants located between amino acids 216 and 251 in the linear sequence (Vrati et al., 1988, Virology 162, 346-353). The antigenic structure of this region has been examined using hyperimmune mouse antiserum against RRV and antiserum against four synthetic peptides representing linear amino acid sequences in the neutralization region of E2. In plaque reduction neutralization tests using hyperimmune antiserum to RRV, an RRV mutant altered at all three neutralization epitopes was markedly more resistant than the parental virus; variants altered at single epitopes could not be distinguished in these tests. Sera from mice immunized with synthetic RRV E2 peptides conjugated to keyhole limpet haemocyanin reacted, in a direct ELISA, with the specific region of RRV represented by the peptide. The same sera did not neutralize or immunoprecipitate RRV in solution or bind to RRV in a capture ELISA. The RRV peptides did not prime mice to react to a subimmunogenic dose of RRV; they did not bind monoclonal or polyclonal antibodies to RRV. We conclude that a significant proportion of the neutralizing antibody response in mice is elicited by epitopes a, b1, and b2 of RRV E2 and that the sites to which neutralizing antibodies bind are formed by complex folding.     

Macrophage migration inhibition induced by tissue antigen in guinea-pigs

Macrophage migration inhibition has been induced with cultures of normal guinea-pig peritoneal exudate cells and mitochondrial antigen of guinea-pig liver. The effect, like the antigen induced phenomenon, is prevented by exposure to trypsin. Puromycin and cycloheximide in contrast did not prevent macrophage migration inhibition. The migration inhibition was compared with the results of skin tests and with passive haemagglutination and immunocyto-adherence tests using liver antigen coated cells. Only the latter test was positive. The migration inhibitory effect is considered in relation to cell-mediated immunity to tissue antigens and its possible role in localization of macrophages in the inflammatory response.     

Characterization of the cytochrome P-450 monooxygenase system in nonciliated bronchiolar epithelial (Clara) cells isolated from mouse lung

The nonciliated bronchiolar epithelial (Clara) cell of the mouse is highly susceptible to toxicants that undergo metabolic activation, presumably because this cell type has high levels of cytochrome P-450 monooxygenases. As a first step in further defining the role of Clara cells in pulmonary xenobiotic activation and detoxication, we have isolated Clara cells (75 to 80% purity) and characterized them morphologically and biochemically. The identity of Clara cells, confirmed by transmission electron microscopy, was based on several features, including abundant agranular endoplasmic reticulum, large mitochondria, and dense secretory granules. Immunocytochemistry of isolated mouse cells showed that the majority were positive with antibodies against three major components of the pulmonary cytochrome P-450 monooxygenase system, cytochrome P-450 isozymes 2 (IIB), 5 (IVB), and NADPH cytochrome P-450 reductase, purified from rabbit lung. The isolated cells also showed a positive reaction with an antibody against the cytochrome P-450 isozyme that is active in the stereoselective metabolism of naphthalene, cytochrome P-450 mN (mN). Immunocytochemistry using the antibody against cytochrome P-450 isozyme 6 (IA1), purified from rabbit lung, showed no reaction in the isolated cells. The presence of intact cytochrome P-450 protein was confirmed by sodium dodecyl sulfate polyacrylamide gel electrophoresis and Western blots of homogenates of isolated cell preparations. The N-demethylation of benzphetamine and epoxidation of naphthalene occurred at easily measurable rates in incubations of isolated Clara cells. In contrast, diols, quinones, and monohydroxylated benzo(a)pyrene metabolites, analyzed by high performance liquid chromatography, were undetectable in extracts of Clara cells incubated with 3H-labeled substrate.(ABSTRACT TRUNCATED AT 250 WORDS)     

Differential distribution of spinal cord field potentials

Summary Electrical stimulation of the sural, superficial peroneal and plantar nerves in anesthetized cats produces a sequence of potentials in the spinal cord lumbosacral enlargement. The distributions of the spinal cord dorsum negative intermediary potential (N1 wave) and of the associated field potential recorded in depth from the spinal gray matter were mapped. The N1 wave produced by the sural nerve was largest at the junction of the S1 and L7 segments, whereas that evoked by the other two nerves was maximum in L6 and L7. The field potentials recorded in depth also showed a differential distribution. The maximum negativity during phase 2, corresponding to the N1 cord dorsum potential, was found to lie laterally in the dorsal horn when the sural nerve was stimulated, but medially when the plantar nerve was activated. The superficial peroneal nerve produced its largest negative field potential in the central region of the dorsal horn. The negative field potentials from the sural and superficial peroneal nerves were not as well separated spatially from each other as they were from the potential evoked by the plantar nerve.     

Factors influencing host susceptibility to meningococcal disease

Host-parasite interactions influencing the development of the protective humoral immune response to Neisseria meningitidis are briefly reviewed. Possible consequences of the observed decreased titres of bactericidal activity specific for meningococcal serogroups A, B and C among patients with gonorrhoea are discussed with reference to: the epidemiology of the two diseases, the protective role of "natural" antibodies to the Neisseria species and the carriage rate of serogroupable strains of N. meningitidis among patients with gonorrhoea and a control population.     

Amiodarone pharmacokinetics. I. Acute dose-dependent disposition studies in rats

Single intravenous bolus doses of amiodarone hydrochloride of 30, 60, 90 and 120 mg/kg were administered to male Sprague-Dawley rats to determine the effects of dose on amiodarone pharmacokinetics. Serial blood samples and total urine were collected over 48 hr and assayed for amiodarone and desethylamiodarone by HPLC. The blood amiodarone concentration-time curves for the four doses were best described by a triexponential equation with terminal half-lives (t _1/2 ) ranging from 17 to 20 hr. Over the dose range studied, no changes in , t _1/2 , or central compartment volume (Vc=1.2–1.4 L/kg) were observed. On the other hand, reductions in amiodarone clearance (CL and steady-state volume of distribution (V _ss of 44% (17.7 to 10.0 ml/min per kg) and 50% (16.4 to 8.2 L/kg), respectively, were noted as the dose of amiodarone increased. The conversion of amiodarone to desethylamiodarone (fm was dose-independent and amounted to approximately 10% of each amiodarone dose. No amiodarone or desethylamiodarone was detected in the urine of any of the treated animals. The blood-to-plasma concentration ratio of amiodarone was concentration-independent and therefore did not account for the dose-dependent changes in V_ss and CL observed. The data suggested that the dose-dependent changes noted were due to an alteration in the volume (s) of the peripheral tissue compartment(s).Supported by a Grant-in-Aid from the American Heart Association, Nebraska Affiliate.     

A single institution experience with Laparoscopic Hernia repair in 791 children

IntroductionThere are many described technique to performing laparoscopic inguinal hernia repair in children. We describe our outcomes using a percutaneous internal ring suturing technique.MethodsA retrospective review of patients under 18 years old who underwent repair between January 2014 - March 2019 was performed. A percutaneous internal ring suturing technique, involving hydro-dissection of the peritoneum, percutaneous suture passage, and cauterization of the peritoneum in the sac prior to high ligation, was used. p < 0.05 was considered significant during the analysis.Results791 patients were included. The median age at operation was 1.9 years (IQR 0.37, 5.82). The median operative time for a unilateral repair was 21 min (IQR 16, 28), while the median time for a bilateral repair was 30.5 min (IQR 23, 41).In total, 3 patients required conversion to an open procedure (0.4%), 4 (0.6%) experienced post-operative bleeding, 9 (1.2%) developed a wound infection, and iatrogenic ascent of testis occurred in 10 (1.3%) patients. Twenty patients (2.5%) developed a recurrent hernia. All but two were re-repaired laparoscopically.ConclusionsThe use of percutaneous internal ring suturing for laparoscopic repair of inguinal hernias in the pediatric population is safe and effective with a low rate of complications and recurrence.     

In vitro analysis of Epstein-Barr virus: Host balance in patients with acutePlasmodium falciparum malaria

Peripheral blood lymphocytes from healthy, Epstein-Barr virus (EB-virus)-seropositive donors and from patients with acutePlasmodium falciparum malaria were tested for their cytotoxicity towards autologous EB-virus-infected B-cells using an in vitro regression assay. Of the 18 cultures from control donors, 88.8% showed the normal pattern of regression. Of the 20 malaria patients in the study, 40% failed to exhibit the normal pattern observed in the control group. Analysis of the lymphocyte subsets showed a high incidence of inverted CD4CD8 ratios in the patient group due to an absolute rise in the CD8 population. This data suggests that the immunosuppressive effects of acute malaria extend to defective control over EB-virus. The relevance of the observations to the aetiology of EB-virusassociated, endemic Burkitt's lymphoma (eBL) is discussed.