Saccades induced electrically from the dorsomedial frontal cortex: evidence for a head-centered representation

The amplitude and direction of saccadic eye movements evoked electrically from the dorsomedial frontal cortex (DMFC) of monkeys vary with starting eye position. This observation has been used to argue that the DMFC codes saccadic eye movements in head-centered coordinates. Whether the amplitude and direction of the evoked saccades are also affected by changes in head position has never been demonstrated. Such a result would argue against a head-centered representation, and instead would suggest a representation anchored to another body part. Tests were conducted on rhesus monkeys to determine whether changing the position of the head with respect to the trunk or changing the position of the head with respect to the gravitational axis alters saccadic parameters. The amplitude and direction of saccadic eye movements remained invariant to such manipulations. These findings confirm the claim that the DMFC encodes saccadic eye movements in head-centered coordinates.     

Sensitivity and specificity of antigen-capture ELISAs for diagnosis of Trypanosoma congolense and Trypanosoma vivax infections in cattle

Sensitivity and specificity of the FAO/IAEA antigen-ELISA kits for diagnosis of bovine trypanosomosis were investigated using sera from experimental cattle infected by tsetse challenge with cloned populations of Trypanosoma congolense (three populations) or T. vivax (one population). The kits are based on monoclonal antibodies that recognise internal antigens of tsetse-transmitted trypanosomes. Ten cattle were infected with each trypanosome population for at least 60 days, and in combination with uninfected cohorts (n = 16) were used in a double-blind study design. Sensitivity and specificity of the tests depended on the choice of positive-negative thresholds expressed as percent positivity with respect to the median OD of four replicates of the strong positive reference serum provided with the kit. In general, while overall specificities were high, sensitivities of the antigen-ELISAs were poor. For example, at a cut-off of 5% positivity, the sensitivities of the antigen-ELISAs were 11% for samples (n = 1162) from T. congolense infected cattle (n = 30), and 24% for samples (n = 283) from T. vivax infected cattle (n = 10). The corresponding specificity values were 95% and 79%, respectively. At a cut-off of 2.5% positivity sensitivity for T. congolense was 25%, and for T. vivax 35%; corresponding specificity values were 85% and 63% respectively. There were no values of the positive-negative threshold at which both sensitivity and specificity were satisfactory. Restricting the analyses to samples taken more than 2 weeks after tsetse challenge did little to improve sensitivity estimates. Trypanosome species specificities of the antigen-ELISAs were also poor. Sensitivity and species specificity of the antigen-ELISA for Trypanosoma brucei infections were not investigated. In contrast to the antigen-ELISA, the sensitivity of the buffy-coat technique when applied to the same experimental animals was fairly high at 67% for T. congolense infections and 60% for T. vivax infections. For samples taken more than 2 weeks after tsetse challenge, high sensitivity estimates of 96% for T. congolense and 76% for T. vivax infections were obtained.     

Association of aortic aneurysm in patients with systemic lupus erythematosus: a series of case reports and a review of the literature

Systemic lupus erythematosus associated aortic aneurysm with or without dissection is an uncommon manifestation of the disease, but it exists and can be a grave complication. We describe 3 patients and compare them to others in the literature. Controlling hypertension and using steroid sparing agents where possible may help in preventing this complication.     

The virion host shutoff protein of herpes simplex virus inhibits reporter gene expression in the absence of other viral gene products

The virion host shutoff (vhs) function of herpes simplex virus induces degradation of host mRNAs at early times and rapid turnover of viral mRNAs throughout infection. Previous studies have shown that disruption of the UL41 gene abrogates vhs activity, but have not determined whether the UL41 polypeptide is the direct inducer of mRNA degradation or whether it is the only virion component required for this activity. In this paper we report that transfection of cells with UL41 inhibits expression of a cotransfected CAT reporter gene and that the inhibition is not dependent upon other viral genes. Inhibition of CAT expression was due to UL41-dependent reduction of CAT mRNA levels. UL41 alleles encoding polypeptides that lacked vhs activity during virus infections exhibited a similar lack of activity in transfected cells. The results indicate that the UL41 polypeptide is the direct inducer of host mRNA degradation following virus infection and that it is the only virion component directly required for this activity. A 382-amino-acid nonsense polypeptide missing the last 107 residues of UL41 lacked inhibitory activity, but was packaged into virions, while a 343-amino-acid nonsense polypeptide lacked both inhibitory activity and the ability to be packaged.     

Low-frequency vibrations in the treatment of patients with acute maxillary sinusitis and ethmoiditis. Non-specific resistance and immunity

Effect of sodium hypochlorite disinfection of impressions on the size and quality of plaster models is studied. Twenty-minute submerging of silicone impressions in 0.5% sodium hypochlorite solution did not change their size and did not deteriorate the quality of surface and hardness of plaster models. Stomalgin impressions cannot be disinfected by sodium hypochlorite solution because of expressed destructive effect of this disinfectant on the impressions.     

Impact of HIV counselling and testing on HIV seroconversion and reported STD incidence among male factory workers in Harare, Zimbabwe

OBJECTIVES: To assess the impact of HIV counselling and testing on HIV seroconversion and incidence of reported sexually transmitted diseases (STDs) among male factory workers in Harare, Zimbabwe. DESIGN: Prospective, observational study among men recruited to participate in a future workplace based AIDS prevention intervention. METHODS: Participants provided STD histories and blood for HIV antibody testing at enrolment and six month intervals during visits to factories. Participants received HIV test results, post test counselling, and free STD services at the project clinic. RESULTS: Between March 1993 and June 1995, 2,414 men were enrolled with 85% follow up. Overall HIV sero-incidence was 2.60 per 100 person-years; the incidence of reported STDs was 10.19 per 100 person-years. Men who obtained their HIV test results had significantly higher HIV sero-incidence and incidence of reported STDs compared to men who did not obtain their results (IRRs: 1.87, 3.47, respectively). Among men who obtained their HIV test results, a non-significant 40% decrease in HIV sero-incidence was observed after obtaining test results compared to before obtaining results (p = 0.18). The incidence of reported STDs, however, increased by 30% after obtaining HIV test results (p = 0.10). CONCLUSIONS: Decreased HIV sero-incidence in the face of increased reported STD incidence suggests that timely treatment of STDs may decrease the risk of acquiring HIV even in the absence of behaviour change. In populations with high rates of HIV and STDs, the greatest benefit of HIV counselling and testing may be achieved by simultaneously offering STD screening and treatment services.     

Measuring spontaneous deleterious mutation process

Parameters of the deleterious mutation process can be estimated using the data on genotypes, phenotypes, or fitnesses. These data can be on long-term evolution, on short-term changes, or on the properties of equilibrium populations. The two most important parameters at the genomic level, the total deleterious mutation rate U and the mutational pressure on fitness P, remain poorly known. Reliable data on the rates of presumably neutral evolution, together with less certain estimates of the functionally important fraction of the genome, suggest that in mammals U > 1. The magnitudes of inbreeding depression in populations of selfers imply U approximately 1 in flowering plants. The straightforward way to estimate P is to assay the decline of fitness in populations with relaxed selection. The relevant data are contradictory, possibly because the results of the measurement of fitness depend strongly on the environmental conditions.     

Inhibitions mediated by glycine and GABAA receptors shape the discharge pattern of bulbar respiratory neurons

Experiments were performed to identify the glycinergic or GABAergic nature, and the timing of discharge, of the neurons which produce chloride-dependent inhibitions on other bulbar respiratory neurons (RNs) during their silent and active phases. RNs recorded extracellularly in pentobarbital-anesthetized or decerebrate cats, were subjected to iontophoretic applications of glutamate, of the glycine antagonist strychnine, and of the GABAA receptor antagonist bicuculline. Both antagonists induced discharge or increased discharge frequency in restricted parts of the respiratory cycle without affecting the discharge frequency in other parts of the cycle. Strychnine most often elicited activity in late-inspiration and early-expiration, but also in early inspiration and in late expiration. Bicuculline was most often effective throughout the entire discharge period of each neuron with no effect during the silent period, although it also acted selectively during late-inspiration in inspiratory neurons, an effect attributed to GABAA receptor blockade. The convergence of glycinergic afferent inputs during late inspiration and early expiration suggests that glycinergic neurons may play an important role in the inspiratory to expiratory phase transition.