Meningococcal infections in the Province of Québec, Canada, during the period 1991 to 1992.

A total of 234 strains of Neisseria meningitidis obtained from hospitalized patients living in the province of Québec during the period 1991 to 1992 were characterized according to their serogroup, serotype, subtype, electrophoretic type, and antimicrobial susceptibility. All these strains were recovered from sterile body fluids, except for one strain that was isolated postmortem from a cutaneous lesion. For both years, serogroup C was the most prevalent (69.7%), followed by serogroup B (27.4%). Serotype 2a represented 80.3% of serogroup C isolates, and P1.2 was the most common subtype associated with this serotype. Clone ET 15 accounted for 76.5% of serogroup C isolates and 90.0% of serotype 2a strains. Although meningococcal disease occurred mostly in children under the age of 5 (9.7 cases per 100,000 children), with a peak incidence for children under 1 (20.3 cases per 100,000 children), most fatalities occurred among teenagers (12 to 19 years old). The total fatality rate was 11.5%, and serogroup C strains were responsible for 88.9% of these fatalities. Thirteen strains had a reduced susceptibility to penicillin G, and 28 strains were resistant to sulfadiazine. One strain was resistant to both rifampin and sulfadiazine and showed a reduced susceptibility to penicillin G.     

Contribution of BK Ca2+-activated K+ channels to auditory neurotransmission in the Guinea pig cochlea

Large-conductance calcium-activated potassium (BK) channels are known to play a prominent role in the hair cell function of lower vertebrates where these channels determine electrical tuning and regulation of neurotransmitter release. Very little is known, by contrast, about the role of BK channels in the mammalian cochlea. In the current study, we perfused specific toxins in the guinea pig cochlea to characterize the role of BK channels in cochlear neurotransmission. Intracochlear perfusion of charybdotoxin (ChTX) or iberiotoxin (IbTX) reversibly reduced the compound action potential (CAP) of the auditory nerve within minutes. The cochlear microphonics (CM at f1 = 8 kHz and f2 = 9.68 kHz) and their distortion product (DPCM at 2f1-f2) were essentially not affected, suggesting that the BK specific toxins do not alter the active cochlear amplification at the outer hair cells (OHCs). We also tested the effects of these toxins on the whole cell voltage-dependent membrane current of isolated guinea pig inner hair cells (IHCs). ChTX and IbTX reversibly reduced a fast outward current (activating above -40 mV, peaking at 0 mV with a mean activation time constant tau ranging between 0.5 and 1 ms). A similar block of a fast outward current was also observed with the extracellular application of barium ions, which we believe permeate through Ca2+ channels and block BK channels. In situ hybridization of Slo antisense riboprobes and immunocytochemistry demonstrated a strong expression of BK channels in IHCs and spiral ganglion and to a lesser extent in OHCs. Overall, our results clearly revealed the importance of BK channels in mammalian cochlear neurotransmission and demonstrated that at the presynaptic level, fast BK channels are a significant component of the repolarizing current of IHCs.     

Vaccinated mice remain more susceptible to Mycobacterium tuberculosis infection initiated via the respiratory route than via the intravenous route

Mice given Mycobacterium tuberculosis bacilli via the respiratory route succumbed much sooner to infection than mice given 1,000 times more bacilli via the intravenous route. Vaccination provided increased protection to an M. tuberculosis challenge infection; however, mice infected via the respiratory route remained much more susceptible.     

Effect of target size on anomalous sensory responses in the Bagolini striated lens test

Different results obtained by different methods of retinal correspondence testing are generally accepted to be a sign of the depth of the anomalous sensory adaptation. The Bagolini striated lens test is considered a standard "natural" test to which others are compared. In this study, the Bagolini striated lens test was performed on 25 strabismic subjects using three target sizes in order to determine if target size might be a factor in response variability. Kappa Measure of Agreement, used to analyze the results statistically, showed a moderately high to high level of agreement among the three targets. This indicates that practitioners can feel confident of consistent test results on the striated lens test using any of the three readily available target sizes selected. A brief literature review has been provided as a guide to the theories of strabismus and correspondence and to emphasize the purpose of this research.     

The locus of control: It’s significance in the irritable bowel syndrome

PSYCHOLOGICAL factors have a role in Irritable Bowel Syndrome symptomatology. The locus of control test determines an individual’s degree of internality or externality. The degree of internality or externality does not influence the site of major Irritable Bowel Syndrome symptomatology. Externalizers have a worse prognosis than internalizers. This effect on prognosis should be borne in mind when testing for diet and or drug efficacy.     

Impact of Mental Health Treatment on Suicide Attempts

This paper analyzes the impact of mental health treatment on suicide attempts. While prior work demonstrates the effectiveness of mental health treatment at reducing suicide risk, few studies examine nationally representative populations or use broad measures of access to mental health services. A methodological problem can arise in studies of mental health treatment and suicidal behavior because a suicide attempt can result in the use of more mental health services. Using nationally representative survey data combined with national estimates of provider availability, this paper employs a methodological correction to address that potential problem of reverse causation. This paper uses measures of the density of health care providers in an area as statistical instruments for use of mental health treatment in an analysis of the impact of mental health treatment on suicide attempts. This study finds that mental health treatment significantly reduces suicide attempts.