Cross-clade inhibition of HIV-1 replication and cytopathology by using RNase P-associated external guide sequences

RNase P complexes have been proposed as a novel RNA-based gene interference strategy to inhibit gene expression in human malignancies and infectious diseases. This approach is based on the sequence-specific design of an external guide sequence (EGS) RNA molecule that can specifically hybridize to almost any complementary target mRNA and facilitate its cleavage by the RNase P enzyme component. We designed a truncated RNase P-associated EGS molecule to specifically recognize the U5 region of HIV-1 mRNA and mediate cleavage of hybridized mRNA by the RNase P enzyme. Genes encoding for this U5-EGS (560) molecule, as well as a U5 EGS (560D) antisense control, were cloned into retroviral plasmids and transferred into a CD4(+) T cell line. Transfected cells were exposed to increasing concentrations of HIV-1 clinical isolates from clades A, B, C, and F. Heterogeneous cultures of CD4(+) T cells expressing the U5 EGS (560) molecule were observed to maintain CD4 levels, were devoid of cytopathology, and did not produce HIV p24 gag antigen through 30 days after exposure to all HIV-1 clades at a multiplicity of infection of 0.01. Identical cells expressing the U5 EGS (560D) antisense control molecule underwent a loss of CD4 expression, produced elevated levels of HIV-1, and formed large syncytia similar to untreated cells. When the viral inoculum was increased at the time of exposure (multiplicity of infection = 0.05), the inhibitory effect of the U5 EGS (560) molecule was overwhelmed, but viral-mediated cytopathology and particle production were delayed compared with control cell populations. Viral replication and cytopathology associated with infection of multiple HIV-1 clades can be effectively inhibited in CD4(+) cells expressing the RNase P-associated U5 EGS (560) molecule.     

A rapid screen of the severity of mild traumatic brain injury

This study investigated the sensitivity of information processing, recall and orientation tasks to the presence of mild Traumatic Brain Injury (mTBI). Fifty-six (40 male, 16 female) mTBI patients and 85 (57 male and 28 female) controls with orthopaedic injuries were tested within 24 hr of injury in the Department of Emergency Medicine. mTBI patients answered fewer orientation questions and recalled fewer words in delayed recall than orthopaedic patients. mTBI patients judged fewer sentences in 2 min than orthopaedic controls, and female mTBI patients judged fewer sentences than male mTBI patients. Male mTBI patients correctly recalled fewer words during immediate memory and learning than female mTBI patients and orthopaedic controls. Those mTBI patients with a history of previous head injuries did not perform more poorly than those mTBI patients without previous head injuries. These results indicate that tests of speed of information processing, word learning and orientation questions are sensitive to the acute effects of mTBI.     

Infrequent parental monitoring predicts sexually transmitted infections among low-income African American female adolescents

OBJECTIVE: To prospectively determine (using an 18-month follow-up period) the association between African American female adolescents' perceptions of parental monitoring and their acquisition of biologically confirmed infection with Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis. DESIGN: A prospective cohort study of 217 African American female adolescents enrolled in the control arm of a randomized trial of a human immunodeficiency virus prevention intervention program. SETTING AND PARTICIPANTS: A volunteer sample of adolescents (aged 14-18 years) recruited from low-income neighborhoods characterized by high rates of unemployment, substance abuse, violence, and sexually transmitted diseases. MAIN OUTCOME MEASURES: Adolescents provided 2 self-collected vaginal swab specimens. One was tested for C. trachomatis and N. gonorrhoeae DNA with ligase chain reaction. The other was used to inoculate culture medium for T. vaginalis. Identical assay procedures were repeated at the 6-month, 12-month, and 18-month follow-up intervals. RESULTS: Adjusted odds ratios indicated that adolescents who perceived infrequent parental monitoring at baseline were 1.8 (95% confidence interval, 1.01-3.21) and 2.4 (95% confidence interval, 1.22-4.87) times more likely to acquire chlamydia or trichomoniasis, respectively, compared with their counterparts who perceived greater levels of monitoring. Similarly, adolescents who perceived infrequent parental monitoring were 2.1 (95% confidence interval, 1.16-3.74) times more likely to test positive for a sexually transmitted infection during the course of the 18-month follow-up period. CONCLUSIONS: Adolescents' perceptions of their parental-monitoring levels predicted subsequent acquisition of biologically confirmed chlamydia and trichomoniasis infections. These findings suggest that expanded efforts leading toward effective clinic- and community-based sexually transmitted infection intervention programs involving parents may be warranted.     

Evaluation of a new thermometer for rapid axillary temperature measurement in preterm infants

Mercury-in-glass thermometers are considered the "gold-standard" for temperature measurements, but require at least 4 minutes for accuracy. Electronic thermometers sample temperature measurements over a shorter period. The objective of this study was to evaluate the accuracy and reproducibility of the Penguin (Medisim, Jerusalem, Israel) and the IVAC (San Diego, CA) Temp plus II thermometers in preterm infants. Axillary temperature was obtained in 50 thermally stable preterm infants each time with the mercury-in-glass, the IVAC, and the Penguin thermometers. Analysis of variance F-test, and linear regression analyses were used to test correlation of each electronic thermometer with the mercury-in-glass one, and the effect of body weight. Temperature measurement taken with the Penguin thermometer was significantly higher than that measured with the two other ones, p < 0.001. The differences in means and in variances were not significantly different between IVAC and mercury-in-glass, while the variance of the Penguin measurement was higher than that of the two other instruments (p < 0.001). The IVAC instrument correlated more tightly with the mercury-in-glass (r = 0.89, p < 0.001) than did the Penguin (r = 0.54, p < 0.001). There was an inverse correlation between the deviation of the Penguin measurement from the mercury-in-glass and the weight of the patient ( p < 0.08), while no significant correlation was found between the deviation of the IVAC measurement from the mercury in glass and the patient's weight (p = 0.56). Measurements of axillary temperature using the Penguin thermometer in incubated preterm infants are less accurate and less reproducible than those obtained using the IVAC or the glass thermometers.     

The NMDA-to-AMPA ratio at synapses onto layer 2/3 pyramidal neurons is conserved across prefrontal and visual cortices

To better understand regulation of N-methyl-d-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor complements across the cortex, and to investigate NMDA receptor (NMDAR)-based models of persistent activity, we compared NMDA/AMPA ratios in prefrontal (PFC) and visual cortex (VC) in rat. Whole cell voltage-clamp responses were recorded in brain slices from layer 2/3 pyramidal cells of the medial PFC and VC of rats aged p16-p21. Mixed miniature excitatory postsynaptic currents (mEPSCs) having AMPA receptor (AMPAR)- and NMDAR-mediated components were isolated in nominally 0 Mg2+ ACSF. Averaged mEPSCs were well-fit by double exponentials. No significant differences in the NMDA/AMPA ratio (PFC: 27 +/- 1%; VC: 28 +/- 3%), peak mEPSC amplitude (PFC: 19.1 +/- 1 pA; VC: 17.5 +/- 0.7 pA), NMDAR decay kinetics (PFC: 69 +/- 8 ms; VC: 67 +/- 6 ms), or degree of correlation between NMDAR- and AMPAR-mediated mEPSC components were found between the areas (PFC: n = 27; VC: n = 28). Recordings from older rats (p26-29) also showed no differences. EPSCs were evoked extracellularly in 2 mM Mg2+ at depolarized potentials; although the average NMDA/AMPA ratio was larger than that observed for mEPSCs, the ratio was similar in the two regions. In nominally 0 Mg2+ and in the presence of CNQX, spontaneous activation of NMDAR increased recording noise and produced a small tonic depolarization which was similar in both areas. We conclude that this basic property of excitatory transmission is conserved across PFC and VC synapses and is therefore unlikely to contribute to differences in firing patterns observed in vivo in the two regions.     

A population-based comparison between travelers who consulted travel clinics and those who did not

BACKGROUND: Travel to hepatitis A-endemic countries is frequent among North Americans. Such travel carries significant risks for the individuals themselves and for the general population. We documented the patterns of use of travel clinics in a large Canadian adult population. METHODS: Travelers who had visited a hepatitis A-endemic country between 1990 and the time of the survey in 1999 were eligible. Subjects were identified from a representative sample of 4,002 adults from the two largest Canadian provinces. They were contacted by random digit dialing and interviewed by telephone. RESULTS: Only 15% of trips had been preceded by a visit to a travel clinic. The probability of visiting a travel clinic was approximately 10 times greater for travelers considered to be in the high-risk category than for those in the low-risk category, but the former represented only 2% of the total. The probability of visiting a travel clinic was approximately 23 times greater for travelers who were aware of the health risks in their country of destination. Income level was not associated with attendance at a travel clinic, and cost was rarely mentioned as a reason for not attending such a travel clinic before departure. CONCLUSIONS: Each year, millions of Canadian travelers go to hepatitis A-endemic countries without consulting a travel clinic. Active steps must be taken by public health authorities to improve their utilization of health services and prevent the accrued health risk for these travelers.