The goal of this experiment was to determine the correlations among different behavioral and neurobiological measures in aged rats. Aged Sprague-Dawley rats were given a battery of cognitive and sensorimotor tests, followed by electrophysiological assessment of sleep and biochemical measurements of various neurotransmitter systems. The behavioral tests included the following: Activity level in an open field; short-term and long-term memory of a spatial environment as assessed by habituation: spatial navigation, discrimination reversal, and cue learning in the Morris water pool; spatial memory in a T-maze motivated by escape from water; spatial memory and reversal on the Barnes circular platform task; passive avoidance; motor skills. Sleep was assessed by electrographic cortical records. The following neurotransmitter markers were examined: Choline acetyltransferase; the density of nicotinic, benzodiazepine and glutamine receptors in the cortex and caudate nucleus; endogenous levels of norepinephrine, dopamine, and serotonin in the cortex and hippocampus. The duration of bouts of paradoxical sleep was strongly correlated with several cognitive measures and selected serotonergic markers. This finding suggests that changes in sleep patterns and brain biochemistry contribute directly to deficits in learning and memory, or that the same neurobiological defect contributes to age-related impairments in sleep and in learning and memory.

Age Factors↗

PubMedDate not supplied

Measurements of multiply scattered light for on-line monitoring of changes in size distribution of cell debris suspension.

Dual wavelength frequency-domain measurements of photon migration (FDPM) are conducted on filtrate samples obtained from an industrial centrifugation process designed to separate Escherichia coli cell debris from the inclusion bodies. FDPM measurements consist of detecting phase delay of intensity-modulated light at 670 and 820 (or 830) nm. Optical properties of isotropic scattering and absorption are obtained from the regression of phase delay data to the optical diffusion equation. We show that the corresponding intensity-based measurements alone cannot provide accurate and independent estimates for these optical properties. However, FDPM-derived scattering coefficients of filtrate solutions (primarily consisting of 0.1-0.2 micrometer E. coli cell debris) are sensitive to approximately 1 vol % of added inclusion bodies (of 1-2 micrometer size). The technique, theory, and future adaptation of FDPM as an on-line monitor to detect the loss of inclusion bodies in centrifugation following homogenization are presented and contrasted to conventional, intensity-based measurements.

Biotechnology↗

PubMedDate not supplied

SPAM (version 3.2): statistics program for analyzing mixtures.

Explore the source record for details and available documents.

Algorithms↗

PubMedDate not supplied

Sexual behavior and sexually transmitted diseases among male adolescents in detention.

BACKGROUND: Youth in detention represent a medically underserved population at risk for a variety of medical and emotional disorders. GOAL OF THE STUDY: To determine prevalence of STDs and high-risk sexual behaviors for HIV/STD among adolescent males admitted to a juvenile detention facility. STUDY DESIGN: Cross-sectional study of behavioral risk factors and STD prevalence among detained males, 11 to 18 years of age. Study subjects were interviewed for behavioral history and screened for STD. RESULTS: The median number of lifetime partners of the population was 8 (range 1-100), the number of partners in the preceding 4 months was 2 in median (range 0-30), 59% used a condom with their last sex, and consistent condom use in the past 4 months was reported by 37%. A history of sexual intercourse within the last one week was reported by 43%. Chlamydia trachomatis infection rate was 6.9% (66/957), Neisseria gonorrhoeae 4.5% (42/940) and syphilis 0.9% (8/930) including one who seroconverted while in detention. Overall, 12% (109/908) of subjects tested for all three infections were positive for at least one STD. Stepwise logistic regression analysis showed that greater than one partner in the previous 4 months (OR 1.53, 95% confidence interval [95% CI] 1.18-1.98), inconsistent or no condom use in the preceding 4 months (OR 1.77, 95%CI 1.37-2.28), a history of recent STD (OR 1.80, 95%CI 1.33-2.42) and greater than five lifetime partners (OR 2.03, 95% CI 1.41-2.92) were independent predictors of these STDs in this population. CONCLUSION: Detained juvenile males in our study were at a high-risk for STD/HIV infections and probably form a core group of STD transmitters. Vigorous attempt to reduce STD reservoir and change behavior of juveniles in detention, such as our study subjects, is urgently needed for the control of the STD/HIV infections.

Adolescent↗