Cardiovascular and respiratory effects of cobra venom and a venom fraction

The cardiovascular and respiratory effect of whole cobra venom and a purified cobra venom fraction were compared in dogs and cats. Both the crude venom and the fraction affected the respiration of dogs markedly and that of cats to a lesser degree. At lethal doses respiratory failure occurred. Cobra venom greatly lowered the blood pressure and decreased the heart rate of dogs and cats. Lethal doses of the fraction produced minimal hypotension and minimal bradycardia in dogs; sublethal and lethal doses produced a similar bradycardiac response in cats.     

Daytime sleep and performance following a zolpidem and melatonin cocktail

STUDY OBJECTIVES: Pharmacologic enhancement of daytime sleep may help sustain optimal cognitive performance. At effective doses, zolpidem induces sleep but also impairs performance. Combining melatonin with low-dose zolpidem may promote daytime sleep without exacerbating performance impairments seen with high-dose zolpidem alone. DESIGN AND METHODS: Following an 8-hour undisturbed nighttime sleep period, 80 subjects (50 men, 30 women) were administered oral zolpidem 0, 5, 10, or 20 mg at 10:00 am (n = 20 per group) and then oral melatonin 0 or 5 mg at 10:30 am (thus, n = 10 per drug combination) in a double-blind randomized fashion. Subjects napped from 10:00 am to 11:30 am, at which time they were awakened and cognitive tests administered (Restricted Reminding, Paired-Associates, and Psychomotor Vigilance). A second nap ensued from 12:45 pm to 4:00 pm, followed immediately by further testing. RESULTS: Melatonin 5 mg plus zolpidem 0 mg enhanced daytime sleep (P < .05) with no memory or performance impairment (P > .05). Zolpidem 20 mg plus melatonin 0 mg also enhanced daytime sleep (albeit nonsignificantly), but memory and vigilance were impaired (P < .05). Melatonin's sleep-promoting effects were not evident until the second nap. CONCLUSIONS: No advantages to administering melatonin plus zolpidem "cocktails" were evident. Unlike zolpidem, melatonin 5 mg alone improved daytime sleep without impairing memory and vigilance. Functional coupling of sleep-inducing and memory-impairing effects may be specific to benzodiazepine-receptor agonists such as zolpidem, suggesting potential advantages to using melatonin in the operational environment. That melatonin's sleep-promoting effects were delayed for several hours presents a practical consideration that may limit melatonin's usefulness when daytime sleep periods cannot be reliably anticipated or planned in advance.     

The incidence of abnormal morphology and nucleocytoplasmic ratios in 2-, 3- and 5-day human pre-embryos

Human cleaving pre-embryos at 2 and 3 days and cavitated pre-embryos at 5 days post-insemination have been examined for cell number and the incidence of mononucleated cells. At least 60% of polynucleate or anucleate cells have been detected at all these stages and regardless of morphological grading at day 2. It is concluded that even by the time at which pre-embryo replacement would occur therapeutically, the majority of pre-embryos are unlikely to have full developmental potential. The possible origins of the abnormalities of nucleocytoplasmic ratios are discussed.     

The Perception of Procedures Questionnaire: Psychometric Properties of a Brief Parent Report Measure of Procedural Distress

Reported the reliability and validity of the Perception of ProceduresQuestionnaire (PPQ), a 19-item parent-report measure developedto assess child and parent distress related to lumbar puncturesand bone marrow aspirates in the diagnosis and treatment ofchildhood cancer. PPQ data from 140 mothers and 96 fathers ofchildren and adolescents with leukemia in a first remissionwere analyzed separately. Factor analyses yielded five factorsfor mothers and fathers: Parent Satisfaction; Child Distress:During; Child Distress: Before; Parent Distress; and ParentInvolvement. Internal consistency (Cronbach's alpha) was highfor the total score and the five factor scores as were interraterreliabilities between mothers and fathers. Validity was determinedusing the Parenting Stress Index-Short Form, the Pediatric OncologyQuality of Life Scale, and parent and nurse ratings during procedures.Factors 2 and 3, assessing child distress, show strong associationswith the validation measures and support the distinction betweendistress before and during procedures. This developing scaleis recommended for use in the assessment and evaluation of childand parent procedure-related distress in pediatric oncology.     

A unified framework for mapping quantitative trait loci in bivalent tetraploids using single-dose restriction fragments: a case study from alfalfa

The development of statistical methodologies for quantitative trait locus (QTL) mapping in polyploids is complicated by complex polysomic inheritance. In this article, we propose a statistical method for mapping QTL in tetraploids undergoing bivalent formation at meiosis by using single-dose restriction fragments. Our method is based on a unified framework, one that uses chromosome bivalent pairing configuration and gametic recombination to discern different mechanisms of gamete formation. Our bivalent polyploid model can not only provide a simultaneous estimation of the linkage and chromosome pairing configuration-a cytological parameter of evolutionary and systematic interest-but also enhances the precision of estimating QTL effects and position by correctly characterizing gene segregation during polyploid meiosis. By using our method and a linkage map constructed in a previous study, we successfully identify several QTL affecting winter hardiness in bivalent tetraploid alfalfa. Moreover, our results reveal significant preferential chromosome pairing at meiosis in an F1 hybrid population, which indicates the importance of reassessing the traditional view of random chromosome segregation in alfalfa.