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Biomedical subjects

K Singleton

Publications and source records attributed to K Singleton.

8 recordsLinked to original sources
PubMed1997

School-related issues among HIV-infected children.

OBJECTIVE: Many children with human immunodeficiency virus (HIV) infection are surviving long enough to reach school age. This study describes issues related to school attendance and disclosure of HIV infection in a population of HIV-infected children. METHODS: A statewide pediatric HIV surveillance system was used to collect data on school-age (>/=5 years old) HIV-infected children. In addition, HIV clinic nurses familiar with the child's history participated in a cross-sectional survey that collected information on school-related issues during the 1993-1994 school year. RESULTS: Of the 92 school-age children, only 3 were too ill to attend school. Another 5 children were home-schooled. Of the 84 who attended school outside the home, 25% had severe symptoms of HIV infection (Centers for Disease Control and Prevention [CDC] clinical category C). Absence from school ranged from less than 2 weeks during the year for half of the children (51%) to more than 8 weeks for 9 children (12%). Twenty-nine percent of the children received medication in school, usually administered by the school nurse. Over two thirds of the 50 children ages 5 to 10 years had not been told that they had HIV infection. Only 1 of the 20 children more than 10 years of age was not aware of her HIV infection. For 53% of the children attending school, no school personnel had been informed of the child's HIV infection. Administration of HIV medications at school, age of child, and treatment at one particular HIV clinic were associated with the parents' decision to inform school personnel. In the 47% of cases where the school had been informed, school nurses were most frequently notified, followed by principals and teachers. CONCLUSION: Only 3% of school-age children were too ill to attend school, and almost all were enrolled in public schools. The number of HIV-infected children reaching school age will continue to grow, and public schools will bear the responsibility for educating these children. Health care providers will increasingly be called upon for guidance by both educators and families to assure that HIV-infected children receive the best education possible.

Absenteeism↗
PubMed1995

In situ evidence for DNA fragmentation in Huntington's disease striatum and Alzheimer's disease temporal lobes.

To test the hypothesis that apoptosis is involved in human brain neurodegenerative disorders, we investigated whether DNA fragmentation occurs in Alzheimer's disease (AD). Huntington's disease (HD) and Parkinson's disease, as well as in temporal lobe epilepsy, using neurologically normal post-mortem human brain tissue as a control. Using in situ end labelling of DNA, we found evidence of DNA fragmentation in cells in temporal cortex and hippocampus from patients with AD and in striatum from those with HD. In contrast, only scattered DNA fragmentation positive cells were detected in the pial surfaces of some of the neurologically normal human brains. Thus, cells in the HD striatum and AD temporal cortex exhibited DNA fragmentation, suggesting that apoptosis may be involved in these disorders.

Adult↗
PubMed1994

The osmolarity of adult Drosophila hemolymph and its effect on oocyte-nurse cell electrical polarity.

In ovarian follicles of Drosophila, changes in external osmolarity affect the steady-state potentials of oocytes more than those of nurse cells. Thus the osmolarity of the incubation medium affects the occurrence and the direction of an electrical gradient across the connecting intercellular bridges. At 255 mOsm nurse cell Em averaged 2.5 mV negative to oocyte Em (P < 0.001). At 275 and at 300 mOsm there was no significant difference between oocyte and nurse cell. At 400 mOsm nurse cell Em averaged 1.1 mV positive to oocyte Em (P = 0.007). The osmolarity of adult Drosophila hemolymph was measured by a variation of freezing point depression and averaged 251 +/- 9 (SE) mOsm. The measured osmolarity and measured ionic concentrations of adult Drosophila hemolymph were used to develop an incubation medium, which was used to incubate developing ovarian follicles. Electrical measurements made in this saline, which mimics in vivo conditions, confirmed reports of a nurse cell-oocyte electrical gradient, with nurse cell Em significantly more negative than oocyte Em. Microinjections of the negatively charged dye Lucifer yellow CH showed that this charged molecule accumulated in the oocyte at the in vivo osmolarity, and in the nurse cells at highly elevated osmotic levels.

Animals↗
PubMed1994

MK-801 does not attenuate immediate-early gene expression following an amygdala afterdischarge.

It has been suggested that the increased transient expression of immediate-early gene transcription factors seen in nerve cells following an afterdischarge may initiate longer lasting or permanent changes in gene expression which underly the development of kindling. Since the development of kindling is sensitive to pharmacological blockade of the N-methyl-D-aspartate receptor, we tested whether the increased expression of the immediate-early genes c-fos, jun-B, c-jun, krox-20, and krox-24 following a kindling afterdischarge was also sensitive to N-methyl-D-aspartate receptor blockade by MK-801. In this report we demonstrate that all five immediate-early genes are induced by an amygdala afterdischarge. N-methyl-D-aspartate receptor blockade by a dose of MK-801 that significantly retards the development of amygdala kindling failed to attenuate immediate-early gene expression. These results suggest that although expression of these five immediate-early genes occurs after an amygdala afterdischarge their expression is not involved in the N-methyl-D-aspartate receptor-mediated component of amygdala kindling.

Amygdala↗
PubMed1993

Is c-Jun involved in nerve cell death following status epilepticus and hypoxic-ischaemic brain injury?

Neurons undergoing delayed neuronal death produced by hypoxia-ischaemia (HI) or status epilepticus (SE) showed a massive expression of c-Jun in their nuclei 24 h after the insult. With SE there was also a weaker induction of c-Fos and Jun B in dying neurons. SE induced in the presence of the NMDA antagonist MK-801 produced no delayed c-Jun expression in the hippocampus and nerve cell death did not occur in this region, although there was a delayed c-jun expression in the amygdala/piriform region, and cell death occurred in this area. Activation of central muscarinic receptors with pilocarpine, or block of D2 dopamine receptors with haloperidol, treatments which do not cause neuronal damage, strongly induced Fos and Jun B in hippocampal and striatal neurons, but only induced c-Jun very weakly. Thus, c-Jun may participate in the genetic cascade of events that produce programmed cell death in neurons.

Animals↗