Immunological identification of Neisseria gonorrhoeae with monoclonal and polyclonal antibody coagglutination reagents.

The reliability of immunological identification of Neisseria gonorrhoeae using polyclonal and monoclonal antibody coagglutination reagents has been evaluated. When clinical isolates of neisseriae were tested in an "in use" trial the sensitivity and specificity of each reagent were similar and the overall agreement with carbohydrate utilisation was 97.9% (141/144) for the polyclonal antibody reagent and 97.2% (140/144) for the monoclonal reagent. When results of testing 13 stock cultures of N lactamica and five stock cultures of beta-lactamase producing Branhamella catarrhalis were combined with the results for clinical isolates of non-gonococcal neisseriae the agreement with carbohydrate utilisation was 86.5% (64/74) for the polyclonal reagent and 97.3% (72/74) for the monoclonal reagent: this difference is statistically significant at the 5% level. Calculation of positive and negative predictive values showed differences in the reliability of the coagglutination reagents when testing Gram negative diplococci isolated from various anatomical sites. The value and limitations of the polyclonal and monoclonal reagents were similar with respect to anogenital isolates: N gonorrhoeae was confirmed by a positive result but not excluded by a negative result. The monoclonal reagent was superior for testing throat isolates; although a negative result with either reagent confirmed Gram negative diplococci as non-gonococcal neisseriae, a positive result with the monoclonal reagent was more reliable (predictive value 93%) than a positive result with the polyclonal reagent (predictive value 86%).     

Hypoxia and incorporation of 3H-thymidine by cells of the rat pulmonary arteries and alveolar wall.

In the pulmonary arterial circulation hypoxia produces increase in thickness of the medial muscle coat as well as of the adventitia; in addition muscle appears in smaller arteries than is normal and the number of small arteries that fill on Micropaque-gelatin injection is reduced. To assess the role of hyperplasia in these changes, the uptake of 3H-thymidine by the cells of the pulmonary arterial wall has been studied in rats exposed to hypobaric hypoxia (exposure to 380 torr) after 1, 3, 5, 7, 10, and 14 days. Using autoradiographs of 1-micron sections, the glutaraldehyde-distended intrapulmonary hilar muscular artery, the peripheral, intraacinar arteries less than 100 micron in external diameter, and the alveolar wall had different patterns of uptake. In the hilar pulmonary artery, after 24 hours of exposure, the labeling index for adventitial fibroblasts is increased eightfold over the control value, and for endothelial cells, threefold, while for medial smooth muscle cells, there is a gradual and small increase to Day 14. Newly muscularized intraacinar arteries are first apparent at Day 3, when they comprise 40% of the intraacinar arteries, increasing to 80% at Day 7. No decrease in density of arteries is found. Uptake of 3H-thymidine by new muscle cells is not apparent until Day 5 when labeling is maximum. The endothelial cells of the newly muscularized arteries show an increased labeling index only at Days 7 and 10. The veins and normally muscular arteries do not show these changes. In the alveolar walls, the concentration of labeled cells is significantly above the control value at Days 3, 5, and 7 and significantly below, at Day 14. At this level, the interstitial, epithelial, and endothelial cells contribute to the increase.     

Chloroform toxicity in mice: correlation of renal and hepatic necrosis with covalent binding of metabolites to tissue macromolecules

Chloroform (CHCl₃) treatment caused centrolobular hepatic necrosis in mice of both sexes whereas renal necrosis was observed only in male mice. Following administration of ¹⁴CHCl₃ to mice, substantial amounts (about 3 mmole/g) of radiolabeled material were covalently bound to proteins in the liver and kidney. The amount of convalent binding paralleled the extent of renal and hepatic necrosis both in normal animals and in male mice pretreated with either phenobarbital or piperonyl butoxide, agents which induce or block, respectively, microsomal drug metabolizing enzymes. These results suggest that the covalent binding is due to a metabolite of CHCl₃. Evidence that the covalent binding is causally related to the tissue necrosis was obtained from autoradiograms showing that the radioactivity is located mainly in the necrotic lesions.     

The carriage of pro-inflammatory cytokine gene polymorphisms in recurrent pregnancy loss

PROBLEM: Recurrent pregnancy loss (RPL) affects 2-4% of couples, and remains largely unexplained. Recent studies have examined the role of cytokines in the maintenance of normal pregnancy, which is linked with an increased expression of Th2 cytokines. Overexpression of Th1 cytokines is associated with RPL. Knowing that functional polymorphisms exist for certain cytokines, it has therefore been suggested that women with RPL may have a genetic predisposition to overexpress Th1 cytokines. METHOD OF STUDY: The genes for interleukin-1 beta (IL-1beta) and tumor necrosis factor alpha (TNF-alpha) carry functional gene polymorphisms. In both cases these are biallelic polymorphisms that can be detected by polymerase chain reaction followed by restriction fragment length polymorphism. The aim of this pilot study was to assess whether carriage of the rarer alleles (TNF*2 and IL-1B*2) could act as independent risk factors in recurrent miscarriage. RESULTS: We found an increased incidence in the carriage of TNF*2, more pronounced in those women with two or more miscarriages. Carriage of the IL-1B*2 either alone or in association with TNF*2 was not associated with recurrent miscarriage. CONCLUSION: There may be a role for these cytokine gene polymorphisms in RPL.     

Striatonigral GABA,dynorphin, substance P and neurokinin A modulation of nigrostriatal dopamine release: evidence for direct regulatory mechanisms

Summary The striatonigral pathway contains several neurotransmitters which may regulate the activity of the nigrostriatal dopamine projection in the rat. This was investigated by measuring extracellular dopamine levels in the striatum, using microdialysis, after injections of GABA (300 nmol/0.2 l), dynorphin A (0.5 nmol/0.2 l), substance P (0.07 mnol/0.2 l) or neurokinin A (0.09 nmol/0.2 l) into the ipsilateral substantia nigra, pars reticulata (SNR). Intranigral injections of GABA or dynorphin A inhibited, while intranigral injections of substance P or neurokinin A stimulated dopamine levels in the ipsilateral striatum. In rats with ibotenic acid lesions (2.5 g/0.5 l) in the SNR, intranigral injections of GABA or dynorphin A inhibited, while intranigral injections of substance P or neurokinin A stimulated dopamine levels in the ipsilateral striatum. These responses were not significantly different than those in unlesioned rats. Analysis of the intranigral lesion with in situ hybridization revealed a heavy loss of glutamic acid decarboxylase mRNA expression in the SNR and a significant loss of tyrosine hydroxylase (TH) mRNA expression in the SNC. Immunohistochemical analysis revealed a disappearance of TH-Like immunoreactivity (LI) im dendrites in the SNR, a considerable loss of TH-LI cell bodies in the SNC and a restricted loss of neuropeptide K-LI in the SNR around the tip of the injection cannula. Furthermore, lesioned rats rotated ipsilateral to the lesion after apomorphine (1 mg/kg, s.c.), indicating that the basal ganglia output mediated via the SNR GABA neurons was impaired on the lesioned side. Analysis of the striatum revealed that a dense TH-LI fiber network could still be seen on the lesioned side. Furthermore, basal and amphetamine stimulated extracellular dopamine levels in the striatum on the lesioned side were not significantly depleted. This indicates that the ascending nigrostriatal dopamine projection was functionally intact on the lesioned side. These findings indicate that intranigral GABA, dynorphin A, substance P and neurokinin A modulation of ipsilateral striatal dopamine release is mediated via direct action on the nigrostriatal projection. Thus, it is suggested that the striatonigral pathway, which contains GABA, dynorphin, substance P and neurokinin A, exerts a direct regulatory effect on the activity of the nigrostriatal dopamine projection.     

Clinical and pathological variability of infection by enterohaemorrhagic (Vero cytotoxin producing) Escherichia coli.

The clinical and pathological features of five sporadic cases of enteric infection caused by Escherichia coli O157 (enterohaemorrhagic or Vero cytotoxin-producing E coli showed a range of features. These included one case with pseudomembranous colitis, one with an acute exacerbation of ulcerative colitis, and three with enterocolitis. Diagnostic difficulties encountered initially in four of the five cases were finally resolved by correlating the results of microbiological with histopathological investigations. In view of the heterogeneity of clinical and histological signs and symptoms, it is concluded that all patients with abdominal pain and diarrhoea or rectal bleeding should have early microbiological investigation.     

The efficacy in Navajo infants of a conjugate vaccine consisting of Haemophilus influenzae type b polysaccharide and Neisseria meningitidis outer-membrane protein complex

BACKGROUND AND METHODS. Several conjugate vaccines against Haemophilus influenzae type b have been developed in the search for one that induces protection even in young infants. We evaluated the safety and efficacy of a conjugate vaccine that links the H. influenzae type b capsular polysaccharide to the outer-membrane protein complex (OMPC) of Neisseria meningitidis serogroup B. We conducted a double-blind, placebo, controlled trial in Navajo infants, who are at high risk for systemic infections caused by H. influenzae type b. The infants were randomly assigned to receive the first dose of vaccine or placebo at 42 to 90 days of age and the second at 70 to 146 days of age. RESULTS. Of the infants in the trial, 2588 were assigned to receive the vaccine and 2602 to receive placebo. The mean follow-up was 269 days in the vaccine group and 267 days in the placebo group. Before the age of 18 months, there was 1 systemic H. influenzae type b infection in the vaccine group, as compared with 22 in the placebo group (P less than 0.001; point estimate of efficacy, 95 percent; 95 percent confidence interval, 72 to 99 percent). Of the 22 H. influenzae type b infections in the placebo group, 13 were meningitis. Among the children who received both doses, there was 1 H. influenzae type b infection in the vaccine group (n = 2056) and 14 in the placebo group (n = 2105) (P less than 0.001; point estimate of efficacy, 93 percent; 95 percent confidence interval, 53 to 98 percent). The single infection in the vaccine group occurred at 15 1/2 months of age in an infant with osteomyelitis. Between the first and second doses there were no H. influenzae type b infections in the vaccine group and eight in the placebo group (P less than 0.005; point estimate of efficacy, 100 percent; 95 percent confidence interval, 41 to 100 percent). CONCLUSIONS. The H. influenzae type b OMPC vaccine, administered at 2 and 4 months of age, is safe and induces a high rate of protection against invasive disease caused by H. influenzae type b in infants under the age of 18 months. Protection begins after the first dose.