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Biomedical subjects

C W Hall

Publications and source records attributed to C W Hall.

At least 19 recordsLinked to original sources
PubMed2000

Temporal stability of the Learning Efficiency Test-II for adults.

This study examined the temporal stability of the Learning Efficiency Test-II with 101 undergraduate students over a mean test-retest time interval of 19 days. Temporal stability estimates were .79 for the Visual Modality factor score, .75 for the Auditory Modality factor score, and .80 for the Global Memory factor score. A repeated measures analysis of variance for these three factor scores indicated no significant mean differences from Test 1 to Test 2. Slightly lower retest correlations were obtained for each of the 12 subtests, with correlations ranging from .44 to .70. The findings indicate that some subtests are reliable to assess the memory processing of adults over time and also highlight the stability over 19 days of memory processes for intact learners. Other studies with older groups of persons are needed to examine the stability of scores.

Achievement↗
PubMed1999

Gender and racial differences in mathematical performance.

The authors examined gender and racial differences in mathematics performance among 5th- and 8th-grade students in the United States. Math performance was assessed by scores on the math-concepts and math-computation sections of the California Achievement Test (CTB/McGraw-Hill, 1986) given at the end of the previous year. There were no significant gender differences, but in both grades, the White students scored significantly higher than the Black students. The racial differences were more pronounced in the scores for concepts than in the scores for computation. Responses to a parent questionnaire showed significant relationships between parents' self-reported math anxiety, parents' most advanced math course, and parents' education level in relation to the child's math performance. Differences in these relationships suggest that, although parents' beliefs and attitudes about math influence their child's math performance, the relationship is complex and may vary with race.

Achievement↗
PubMed1999

College students' perception of facial expressions.

95 college students were administered the Facial Expressions subtest of the Diagnostic Analysis of Nonverbal Accuracy to measure perception of nonverbal cues. Participants also completed the Nowicki-Strickland Locus of Control Scale and responded to a short questionnaire regarding their beliefs about their own ability to perceive nonverbal cues as well as how effective they felt others were in perceiving nonverbal cues. A significant correlation between locus of control and perception of adult facial expressions indicated those students with a more internal locus of control had higher scores on correct perception of adult facial expression. There was no significant correlation between locus of control and facial expressions of children. Sex differences were also found in perception of nonverbal cues. Female students scored higher in correctly perceiving facial expressions than the men. Participants also scored higher in correctly perceiving facial expressions of children than of adults.

Adult↗
PubMed1999

The influence of gender on the ocular surface.

PURPOSE: Dry eye is more prevalent among women than men. To examine whether gender influences the ocular surface, conjunctival goblet-cell density was monitored for a 30-day period. Changes in goblet-cell density are a sensitive marker for ocular surface disease. METHODS: Six men and twelve women who were free from ocular surface disease were sampled by impression cytology on the inferior bulbar conjunctiva every other day for 30 days. Samples were analyzed for goblet-cell content. The mean age of the subjects was 24 years for the men and 25.4 years for the women. A minimum of 200 epithelial cells were scored per microscopic field examined. RESULTS: There is a statistically significant difference in goblet-cell count between men and women over the 30-day test period. The mean goblet-cell count measured for men was 3.75% +/- 1.04%, while the mean count for women was 2.545% +/- 0.8%. When the data on women were replotted with reference to the menstrual cycle, the largest and longest depression of goblet-cell count occurs midcycle, around the time of ovulation. A significant difference in goblet-cell count was also noted when subjects using oral contraceptives (3.065% +/- 0.98%) are compared with those not using oral contraceptives (2.28% +/- 0.92%). CONCLUSION: It appears there may be a reproductive hormonal influence on conjunctival goblet-cell count.

Adult↗
PubMed1998

Synaptic effects of nitric oxide on enkephalinergic, GABAergic, and glutamatergic networks of the rat periaqueductal gray.

Previous studies have shown that the injection of nitric oxide (NO) donating compounds into the dorsal periaqueductal gray region of the midbrain (PAG) decreases mean arterial pressure (MAP), while the injection of NO synthase (NOS) inhibitors increases MAP. In this study we used both in-vivo and in-vitro preparations and examined the effect of a NO donor and a NOS inhibitor on MAP, membrane properties, and synaptic activities in PAG neurons. We found that: (1) Injection of the NO donor hydroxylamine (HA) into the dorsal PAG decreased MAP, while the injection of the neuronal NOS (nNOS) inhibitor, 1-(2-trifluoromethylphenyl) imidazole (TRIM) increased MAP. These responses were consistent and site-specific. (2) HA-evoked hypotensive responses were mediated by PAG neuronal activity, because they were blocked by pre-injection with gamma-amino-butyric acid (GABA). (3) HA consistently increased the rate of observable synaptic events while TRIM consistently decreased the rate of observable synaptic events. (4) Bicuculline (BIC) and naloxone (NAL) blocked HA-evoked increases in the rate of observable inhibitory synaptic events. (5) Perfusion with sodium nitroprusside (SNP) and illumination with bright light consistently elevated rates of observable synaptic events, and SNP-evoked increases of excitatory synaptic events were blocked by pretreatment with glutamic acid antagonists. (6) PAG-medullary projecting neurons exhibited similar response patterns. The results of this study suggest that: (1) NO production within the PAG is a major component of PAG-mediated cardiovascular responses. (2) The effects of NO may be mediated in part by increased presynaptic vesicular release of glutamic acid, GABA, and enkephalin.

Animals↗
PubMed1997

Reduced utilization of Man5GlcNAc2-P-P-lipid in a Lec9 mutant of Chinese hamster ovary cells: analysis of the steps in oligosaccharide-lipid assembly.

Recently we reported that CHB11-1-3, a Chinese hamster ovary cell mutant defective in glycosylation of asparagine-linked proteins, is defective in the synthesis of dolichol [Quellhorst et al., 343:19-26, 1997: Arch Biochem Biophys]. CHB11-1-3 was found to be in the Lec9 complementation group, which synthesizes polyprenol rather than dolichol. In this paper, levels of various polyprenyl derivatives in CHB11-1-3 are compared to levels of the corresponding dolichyl derivatives in parental cells. CHB11-1-3 was found to maintain near normal levels of Man5GlcNAc2-P-P-polyprenol and mannosylphosphorylpolyprenol, despite reduced rates of synthesis, by utilizing those intermediates at a reduced rate. The Man5GlcNAc2 oligosaccharide attached to prenol in CHB11-1-3 cells and to dolichol in parental cells is the same structure, as determined by acetolysis. Man5GlcNAc2-P-P-polyprenol and Man5GlcNAc5-P-P-dolichol both appeared to be translocated efficiently in an in vitro reaction. Glycosylation of G protein was compared in vesicular stomatitus virus (VSV)-infected parent and mutant; although a portion of G protein was compared in vesicular stomatitus virus (VSV)-infected parent and mutant; although a portion of G protein was normally glycosylated in CHB11-1-3 cells, a large portion of G was underglycosylated, resulting in the addition of either one or no oligosaccharide to G. Addition of a single oligosaccharide occurred randomly rather than preferentially at one of the two sites.

Animals↗
PubMed1997

The medial preoptic nucleus of the hypothalamus modulates activity of nitric oxide sensitive neurons in the midbrain periaqueductal gray.

Stimulation of the medial preoptic nucleus of the hypothalamus (MPO) has been shown to produce decreases in mean arterial pressure (MAP) by a pathway involving the periaqueductal gray region of the midbrain (PAG). Previous studies have shown that the injection of nitric oxide (NO) donating compounds into the dorsal PAG also decreases MAP, while the injection of nitric oxide synthase (NOS) inhibitors increases MAP. Collectively these studies suggest that the MPO elicited hypotensive response may involve NO production in PAG neurons. In this study, we investigated this hypothesis. We found that: (1) Bilateral injection of the NOS inhibitor 7-nitro indazole (7-NI) into the dorsolateral PAG cell columns produced elevations in MAP in a highly consistent and site specific fashion. (2) Microinjection of 7-NI in quantities that were too low to directly influence MAP blocked the MPO evoked hypotensive response in 9/11 cases. (3) While 41% of dorsal PAG neurons had baseline firing rates that were sensitive to 7-NI, 69% of PAG neuronal responses to MPO stimulation were blocked by 7-NI. (4) Inhibitory responses that were not blocked by 7-NI had significantly shorter latencies to onset in the presence of 7-NI. (5) PAG neurons that projected to the medulla exhibited similar electrophysiologic response patterns. Our results suggest the following: (1) The dorsolateral PAG contains a NO producing hypotensive network. (2) The MPO elicited hypotensive response may utilize this network. (3) Stimulation of the MPO elicits NO dependent responses from PAG neurons, some of which do project to medullary-cardiovascular control centers.

Animals↗
PubMed1997

Synthesis of dolichol in a polyprenol reductase mutant is restored by elevation of cis-prenyl transferase activity.

CHB11-1-3 is a glycosylation mutant of Chinese hamster ovary (CHO) cells, isolated by screening mutagenized cells for those with decreased intracellular lysosomal enzyme activity [C. W. Hall et al. (1986) Mol. Cell. Biochem. 72, 35-45]. CHB11-1-3 synthesizes the lipid polyprenol, the metabolic precursor of dolichol, rather than dolichol, indicating a defect in polyprenol reductase. This defect was demonstrated previously in Lec9 CHO mutants, and cell fusion experiments confirmed that CHB11-1-3 is a member of this complementation group. A revertant of CHB11-1-3, CHBREV, isolated for its ability to grow at 39 degrees C, synthesizes dolichol at near-normal levels. CHBREV is probably a second-site revertant, because it synthesizes three to four times as much polyprenol as CHB11-1-3 and exhibits a similar elevation in the specific activity of cis-prenyl transferase. This higher activity appears to reflect an increase in enzyme molecules rather than the presence of an activator or absence of an inhibitor. These results suggest that CHB11-1-3 is a "K(m)" mutant, because synthesis of higher amounts of the substrate of polyprenol reductase obviates the defect.

Animals↗
PubMed1996

Teenagers' knowledge about prenatal exposure to cocaine.

The current study indicated limited knowledge among 124 teenagers about prenatal exposure to cocaine. Given the widespread problem of substance abuse among teenagers as well as high incidence of teenage pregnancies, there is a need to make this information more readily available.

Adolescent↗
PubMed1995

A comparison of the performance of cognitively disabled children on the WISC-R and WISC-III.

This study compared differences in performance on the WISC-III and on the WISC-R. Sixty-one students with learning impairments, due for reevaluation of their special education placement, were administered the WISC-III as part of a psychological assessment battery. Results indicate a mean difference between WISC-R and WISC-III FSIQ of 7.95 points, which is similar to WISC/WISC-R comparisons. Substantial differences that averaged 9.21 points were found between WISC-R and WISC-III PIQ means. These findings suggest that for a special education sample an average decrease of at least 8 points can be expected on the WISC-III Full Scale IQ. Caution should be exercised when one is considering changes in educational classification or interpreting qualitative differences in performance on WISC-III scores compared with WISC-R scores.

Adolescent↗
PubMed1994

Adjustment issues with adult children of alcoholics.

The current study assessed locus of control, general level of life satisfaction, and self-reported grade-point averages among adults who had experienced either alcoholism within the family of origin, traumatic life events other than alcoholism, or who indicated neither problem during their childhood. Results indicated that both the adult children of alcoholics (ACOA) and traumatic experience (TE) groups had lower life satisfaction scores than the control group. Significantly lower levels of locus of control also were found for the ACOA group in comparison to the control group. There were no significant differences among the three groups based on self-reported GPAs. Results of the current study support the concept that family dysfunction during childhood can influence negatively later life experiences and adjustment.

Activities of Daily Living↗
PubMed1992

Learning styles of LD and NLD ADHD children.

Attention Deficit Hyperactive Disorder (ADHD) children (N = 26) with a learning disability (LD) and without (NLD) were compared on measures of information processing using the Learning Efficiency Test (LET). Method of presentation (visual vs. auditory), order of recall (ordered vs. non-ordered), and memory processes (immediate, short-term, and long-term) were assessed. While both groups showed more difficulty with short-term and long-term memory processes than with immediate memory processes, the ADHD-LD subjects demonstrated more difficulty processing information effectively. Ordered recall was significantly more difficult for both short-term and long-term memory processes than was unordered recall. While both groups demonstrated difficulty with auditory ordered recall under short-term and long-term conditions, the ADHD-LD subjects lost the most information under auditory conditions.

Adolescent↗
PubMed1992

Effects of two treatment techniques on delay and vigilance tasks with attention deficit hyperactive disorder (ADHD) children.

In this study, we examined the effects of two treatment techniques under on-medication and off-medication conditions on the hyperactive behavior patterns of children. Three groups of subjects were compared: a control group, a behavior modification group, and a cognitive training group. The Gordon Diagnostic System (Gordon, McClure, & Post, 1986) was used to assess the subjects at the initial screening, during treatment without medication, and during treatment with medication. The two medication conditions were counterbalanced during the second and third testing sessions. Results showed that when the cognitive intervention was combined with medication, there was a significant improvement in the subjects' ability to delay impulsive responding. However, no significant effects were seen for sustained vigilance for either the behavioral or cognitive groups. Parents rated children in the cognitive group significantly higher than those in the control group.

Attention↗
PubMed1990

Recovery of function in Chinese hamster ovary cell mutants with temperature-sensitive defects in vacuolar acidification.

After 4 h at 41 degrees C, B3853 and M311, temperature-sensitive Chinese hamster ovary cell End1 and End2 mutants, respectively, are pleiotropically defective in endocytosis and trans-Golgi network-associated activities (Roff, C. F., R. Fuchs, I. Mellman, and A. R. Robbins. 1986. J. Cell Biol. 103:2283-2297). We have measured recovery of function after return to the permissive temperature. Based on return of normal transferrin-mediated Fe uptake and sensitivity to diphtheria toxin both mutants had restored endosomal function at 10 h; based on delivery of endocytosed lysosomal enzymes to lysosomes and normal sensitivity to modeccin both had functional late endocytic organelles at 10-12 h; and based on retention of newly synthesized lysosomal enzymes and sialylation of secreted glycoproteins both had functional trans-Golgi network at 6 h. At 10 h, M311 had recovered almost all of its ability to endocytose lysosomal enzymes; B3853 required 30 h to recover fully its ability to endocytose lysosomal enzymes. Slow recovery of mannose 6-phosphate-dependent uptake in B3853 reflected altered trafficking of cation-independent mannose 6-phosphate receptors. Although B3853 had normal amounts of receptor at 6-8 h, it had greatly diminished amounts of receptor at the cell surface. Altered trafficking was also suggested by the finding that B3853 rapidly degraded receptor that had been present before the shift to the nonpermissive temperature.

Animals↗
PubMed1989

Research for ground-water quality management with an emphasis on in situ biorestoration.

It is important to remember that the behavior of contaminants in the subsurface is influenced by chemical and hydrologic parameters as well as biotic considerations, and that a wholistic understanding of these processes will be required for successful ground-water quality management. There is little doubt that vast resources will be devoted to remedial action activities aimed at restoring ground water in coming years. With the average cost of cleaning up a hazardous waste site now approaching five million dollars, the future cost of dealing with existing sources of ground-water contamination will be measured in many billions of dollars and uncalculable hours of effort. Already we can see that, as we begin to understand the processes that control the behavior of pollutants in the subsurface, we can not only reduce these expenditures dramatically, but also assure that the actions taken adequately protect ground water now and in the future.

Bacteria↗
PubMed1988

Field independence and simultaneous processing in preschool children.

The present study examined the relations between field independence and simultaneous processing of preschool children as measured by the Preschool Embedded Figures Test (PEFT) and subtests from the Kaufman Assessment Battery for Children (K-ABC), respectively. Data partially supported the assumption that field-independent children would perform significantly better on simultaneous processing tasks in general. Significant age and sex differences on field-independence/field-dependence and simultaneous-processing abilities were found among the embedded figures task and selected portions of the K-ABC. Analysis of embedded figures further indicated age differences, but no significant sex differences.

Achievement↗
PubMed1987

Regional brain [Met]-enkephalin in alcohol-preferring and non-alcohol-preferring inbred strains of mice.

Scrutiny of the data from these studies reveals that the C58/J alcohol-preferring mice have significantly lower baseline methionine-enkephalin levels in both the corpus striatum and hypothalamus compared to C3H/CHRGL/2 non-alcohol-preferring mice. In other brain regions in these two strains, specifically, pituitary, amygdala, midbrain, and hippocampus, analysis of methionine-enkephalin levels did not show any significant differences. This suggests that the hypothalamus may indeed be a specific locus involved in the regulation of alcohol intake, via the molecular interaction between neuroamines, opioid peptides, as they are influenced by genetics and environment.

Alcohol Drinking↗