Prevalence and incidence of HIV among incarcerated and reincarcerated women in Rhode Island

This study explores recent temporal trends in HIV prevalence among women entering prison and the incidence and associated risk factors among women reincarcerated in Rhode Island. Results from mandatory HIV testing from 1992 to 1996 for all incarcerated women were examined. In addition, a case control study was conducted on all seroconverters from 1989 to 1997. In all, 5836 HIV tests were performed on incarceration in 3146 women, 105 of whom tested positive (prevalence, 3.3%). Between 1992 and 1996, the annual prevalence of HIV among all women known to be HIV-positive was stable (p = .12). Age >25 years, nonwhite race, and prior incarceration were associated with seropositivity. Of 1081 initially seronegative women who were retested on reincarceration, 12 seroconverted during 1885 person-years (PY) of follow-up (incidence, 0.6/100 PY). Self-reported injection drug use (IDU; odds ratio [OR], 3.7; 95% confidence interval [CI], 1.3-10.1) was significantly associated with seroconversion, but sexual risk was not (OR, 1.1; 95% CI, 0.4-3.5). Incarceration serves as an opportunity for initiation of treatment and linkage to community services for a population that is at high risk for HIV infection.     

A balanced whole arm reciprocal translocation resulting in three different adverse pregnancy outcomes.

A family with a whole arm translocation t(13;18)(13p18p;13q18q) was ascertained through a stillbirth with clinical features suggestive of trisomy 18. Two subsequent pregnancies both spontaneously aborted; one was found to have a 69,XXX,t(13;18)mat chromosome constitution while the other had a 45,XY,-13,-18, + der(18)t(13;18)mat chromosome constitution.     

Comparison of Electrical and Ultrasound Neurostimulation in Rat Motor Cortex

Ultrasound (US) is known to non-invasively stimulate and modulate brain function; however, the mechanism of action is poorly understood. This study tested US stimulation of rat motor cortex (100 W/cm², 200?kHz) in combination with epidural cortical stimulation. US directly evoked hindlimb movement. This response occurred even with short US bursts (3?ms) and had short latency (10?ms) and long refractory (3?s) periods. Unexpectedly, the epidural cortical stimulation hindlimb response was not altered during the 3-s refractory period of the US hindlimb response. This finding suggests that the US refractory period is not a general suppression of motor cortex, but rather the recovery time of a US-specific mechanism.     

Brain-body size relations in grasshopper mice

Cranial volumes were measured on museum specimens of two species of grasshopper mice, Onychomys leucogaster brevicaudus and Onychomys torridus pulcher. These were compared with body weights and body lengths, as recorded on the museum tags. On average, females were heavier and slightly longer than males, but they had smaller cranial volumes by about 3%. Statistically, the differences were marginally significant (with no difference in body length for one species), but the pattern of differences was the same in both species, and therefore probably real. This casts suspicion on the common notion that a larger body size requires a larger brain. It also questions the real meaning of encephalization quotients.     

Influence of molecular layer on pyramidal tract neurons

Activity in layer I increases the excitability of pyramidal tract (PT) neurons, the effect being stronger on slow than on fast PT neurons. Extracellular recordings were made from lateral postcruciate cortex of domestic cats, using antidromic activation from medullary pyramid to identify and classify PT neurons. Their responses to contralateral forepaw (CFP) and direct cortical (Ctx) stimulation, 3 to 4 mm caudal to the recording site, were determined before and after placement of vertical cuts between the Ctx stimulating and recording sites. These cuts had a minor effect on the responses of PT neurons to CFP stimulation, but a strong effect on the responses to Ctx stimulation. Cuts through layers I and II markedly delayed the responses of slow PT neurons, but had no effect on fast PT neurons. After deeper cuts (II/III through V/VI), half the fast and half the slow PT neurons failed to respond to Ctx stimulation. Of those that did, fast PT responses were markedly delayed, but slow PT responses were only mildly affected. The Ctx-CFP interactions showed the familiar facilitation-depression sequence. The period of depression was unaffected by any of the vertical cuts, but disappeared after undercutting the stimulus site below layer VI. The period of facilitation depended primarily on layer I for its production, although deeper layers also contributed to the facilitation of fast PT neurons.     

Wide-field conditioning effects on small-field neurons in the posterior sigmoid gyrus of domestic cats

Single neurons were isolated in four different recording sites in sensorimotor cortex of the domestic cat, all sites being topographically related to the contralateral forepaw. Conditioning-testing interactions were made on 409 small-field neurons, the testing input being the contralateral forepaw (also the ipsilateral forepaw in the case of bilateral-field neurons) and the conditioning input being any paw that was ineffective in exciting the neuron. About 29% of the neurons showed inhibitory interactions and 23% showed facilitatory interactions. Of these, about 5.5% showed both effects, according to the conditioning site. Nearly 54% of the neurons failed to show any interaction effects. Most of the latter were isolated in the two posterior recording sites, located in somatosensory area I; the interaction effects were found predominantly in the two anterior recording sites, located in agranular tissue. Neurons that responded only to contralateral forepaw stimulation (sa neurons) and showed facilitatory interactions from the other three paws had response properties characteristic of neurons that respond to all four paws (m neurons). The sa neurons that showed inhibitory interactions from the other three paws did not differ significantly in response properties from those that showed no interaction effects. These findings are relevant to current criteria for the classification of sensorimotor cortex neurons and lead to remarks on the possible thalamic routes that mediate the interaction effects.     

Brain size/body length relations among myomorph rodents.

The relation between cranial volume and body length was examined in 45 species of myomorph rodents to determine how accurately the former can be estimated from the latter. On average within species, cranial capacity was directly proportional to body length (proportional to the cube root of body weight). On average across species, cranial capacity was directly proportional to the square of body length (proportional to the two-thirds power of body weight). Geometric similarity held within species, but the differences in habitus among species within the same genus generated genus slopes that differed from those defined by strict geometric similarity. It was found that cranial capacity could be estimated as accurately from body length as from body weight, and that body length was better if any differences in habitus were involved (because body length is relatively insensitive to habitus). Therefore, body length (or some strong correlate thereof) may serve well as the primary variable in brain paleoallometry.