Differential effects of continuous administration for 1 year of haloperidol or sulpiride on striatal dopamine function in the rat

Administration of haloperidol (1.4–1.6 mg/kg/day) for up to 12 months or sulpiride (102–109 mg/kg/day) for between 6 and 12 months increased the frequency of purposeless chewing jaw movements in rats. N,n-propylnorapomorphine (NPA) (0.25–2.0 mg/kg SC) did not induce hypoactivity in haloperidol-treated rats at any time; sulpiride treatment for 9 and 12 months caused a reduction in the ability of NPA to induce hypoactivity. Haloperidol, but not sulpiride, treatment enduringly inhibited low dose apomorphine effects (0.125 mg/kg SC). After 12 months, sterotypy induced by high doses of apomorphine (0.5–1.0 mg/kg) was exaggerated in haloperidol-, but not sulpiride-treated rats.B_max for specific striatal ³H-spiperone binding was increased by haloperidol, but not sulpiride, treatment throughout the study. B_max for ³H-NPA binding was elevated only after 12 months of both haloperidol and sulpiride treatment. B_max for ³H-piflutixol binding was not alfered by chronic haloperidol or sulpiride treatment. Striatal dopamine-stimulated adenylate cyclase activity was inhibited for the 1st month of haloperidol treatment, thereafter returning to control levels; dopamine stimulation was increased after 12 months of sulpiride treatment. Striatal acetylcholine content was increased after 3 and 12 months of treatment with haloperidol, but was not affected by sulpiride.Chronic administration of sulpiride does not induce identical changes in striatal dopamine function to those caused by haloperidol.     

Apparatus for the rapid measurement of electrocardiographic body surface potentials

A method for the rapid and reproducible recording of 24 chest electrode potentials is described. Rigid electrodes are equally spaced around the thorax in three rows of eight. The electrodes move radially and are spring loaded so as to maintain contact with the skin regardless of the shape of the subject's torso. The inclusion of an impedance convertor in the electrode assembly removes the necessity for using electrode cream. Although equal spacing of the electrodes around the thorax is inefficient in terms of information content per electrode the attention to detail required for electrode placement using the described system is minimised as compared with other multiple lead systems. Furthermore, the principles adopted in the design and construction of the apparatus do not limit the number of chest electrodes to 24.     

West Nile virus risk assessment and the bridge vector paradigm

In the northeast United States, control of West Nile virus (WNV) vectors has been unfocused because of a lack of accurate knowledge about the roles different mosquitoes play in WNV transmission. We analyzed the risk posed by 10 species of mosquitoes for transmitting WNV to humans by using a novel risk-assessment measure that combines information on the abundance, infection prevalence, vector competence, and biting behavior of vectors. This analysis suggests that 2 species (Culex pipiens L. and Cx. restuans Theobald [Diptera: Cilicidae]) not previously considered important in transmitting WNV to humans may be responsible for up to 80% of human WNV infections in this region. This finding suggests that control efforts should be focused on these species which may reduce effects on nontarget wetland organisms. Our risk measure has broad applicability to other regions and diseases and can be adapted for use as a predictive tool of future human WNV infections.     

Exposure to infant siblings during early life and risk of multiple sclerosis

Context  The "hygiene hypothesis" has implicated sibship as a marker of infection load during early life and suggests that exposure or reexposure to infections can influence the developing immune system. Viral infection has also been implicated in the pathogenesis of multiple sclerosis (MS). Objectives  To evaluate whether exposure to infant siblings in early life is associated with the risk of MS, and to explore the possible mechanism for any apparent protective effect, including altered Epstein-Barr virus (EBV) infection patterns. Design, Setting, and Patients  Population-based case-control study in Tasmania, Australia, from 1999 to 2001 based on 136 cases of magnetic resonance imaging–confirmed MS and 272 community controls, matched on sex and year of birth. Main Outcome Measure  Risk of MS by duration of contact with younger siblings aged less than 2 years in the first 6 years of life. Results  Increasing duration of contact with a younger sibling aged less than 2 years in the first 6 years of life was associated with reduced MS risk (adjusted odds ratios [AORs]: <1 infant-year, 1.00 [reference]; 1 to <3 infant-years, 0.57 [95% confidence interval {CI}, 0.33-0.98]; 3 to <5 infant-years, 0.40 [95% CI, 0.19-0.92]; 5 infant-years, 0.12 [95% CI, 0.02-0.88]; test for trend, P = .002). A history of exposure to infant siblings was associated with a reduced IgG response to EBV among controls. Controls with at least 1 infant-year contact had a reduced risk of infectious mononucleosis and a reduced risk of very high composite EBV IgG titers (AOR, 0.33; 95% CI, 0.11-0.98) compared with other controls. The inverse association between higher infant contact and MS was independent of EBV IgG titer. Conclusion  Higher infant sibling exposure in the first 6 years of life was associated with a reduced risk of MS, possibly by altering childhood infection patterns and related immune responses.      

Variables differentiating singly and multiply victimized youth: results from the National Survey of Adolescents and implications for secondary prevention

The authors examined variables differentiating singly and multiply victimized youth with a national household probability sample of 4,023 adolescents. Youth endorsing one episode (i.e., one incident or series of repeat incidents) of sexual or physical assault were classified as singly victimized (n = 435). Multiply victimized youth were those who endorsed multiple discrete episodes of sexual or physical assault and both sexual and physical assault (n = 396). For boys, heightened risk of multiple victimization was associated with family alcohol problems, Native American race, and earlier age at assault onset. For girls, increased multiple victimization risk was associated with family alcohol problems, older current age, and several characteristics of the initial assault episode-earlier age at onset, acquaintance perpetrator, chronicity, perceived life threat, and injury. Findings imply that secondary prevention programs may be strengthened by broadening risk-reduction strategies to address a greater range of victimization experiences. Additional implications for secondary prevention are discussed.