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Biomedical subjects

C L Holt

Publications and source records attributed to C L Holt.

14 recordsLinked to original sources

Development and validation of brief scales to measure collectivism, religiosity, racial pride, and time orientation in urban African American women.

This article describes the development and pilot-testing of brief scales to measure four cultural constructs prevalent in urban African American women. Internal consistency and temporal stability were assessed in two convenience samples (n=47 and n=25) of primarily lower-income African American women. All scales performed well: collectivism alpha=.93, r=.85, p<.001); religiosity (alpha=.88, r=.89, p<.001); racial pride (alpha=.84, r=.52, p<.001); present time orientation (alpha=.73, r=.52, p<.01) and future time orientation (alpha=.72, r=.54, p=.07).

Adolescent↗

Practical applications of genotypic surveys for forensic STR testing.

Legitimate genotype frequency estimation for multiallelic loci relies on component allele frequencies, as population surveys represent only a fraction of possible DNA profiles. Multilocus genotypes from two ethnic human populations, African American (n=195) and U.S. Caucasian (n=200), were compiled at 13 STR loci that are used worldwide in forensic investigation (D3S1358, vWA, FGA, D16S539, TH01, TPOX, CSF1PO, D8S1179, D21S11, D18S51, D5S818, D13S317, and D7S820). Sex-specific AmpFlSTR multiplexes provided stringent PCR-based STR typing specifically optimized for multicolor fluorescence detection. Heterozygosity at each STR locus ranged from 0.57 to 0.89 and encompassed from seven (TH01) to twenty-one (D21S11) alleles. Homozygosity tests, tests based on the distinct numbers of observed homozygous and heterozygous classes, log likelihood ratio tests, and exact tests assessed that the degree of divergence from theoretical Hardy-Weinberg proportions for all 13 STRs does not have practical consequence in genotype frequency estimation. Departures from linkage equilibrium, between loci, that imposed significance to forensic calculations were not indicated by observed variance of the number of heterozygous loci or Karlin interclass correlation tests. For forensic casework, reliable multilocus profile estimates may be obtained from the product of component genotype frequencies, each calculated through application of the Hardy-Weinberg equation to population database allele frequency estimates reported here. The average probability that two randomly selected, unrelated individuals possess an identical thirteen-locus DNA profile was one in 1.8x10(15) African Americans and one in 3.8x10(14) U.S. Caucasians.

Black or African American↗

Does locus of control moderate the effects of tailored health education materials?

Research in health communication has shown that individually tailored health education materials are more effective than traditional or generic materials in producing changes in health-related behaviors. However, tailored materials have not been equally effective for all individuals. Because locus of control affects behavioral outcomes in other self-change interventions, its effect on individuals' responses to tailored messages is of particular interest. The present study examined differences in cognitive responses to tailored and non-tailored weight loss materials among 198 overweight individuals. Weight locus of control significantly interacted with study group (who received either tailored or non-tailored materials), suggesting that externals may respond to tailored health education materials with counter-arguments. Implications for the development and application of tailored health communication materials are discussed.

Adult↗

TWGDAM validation of the AmpFISTR blue PCR amplification kit for forensic casework analysis.

Studies were performed as recommended by the Technical Working Group on DNA Analysis Methods (TWGDAM) committee to validate the AmpFISTR Blue PCR Amplification Kit for forensic casework applications. The kit coamplifies the tetranucleotide short tandem repeat (STR) loci D3S1358, vWA, and FGA. The dye-labeled amplification products were electrophoresed and detected directly using the ABI PRISM 377 DNA Sequencer or the 310 Genetic Analyzer. CEPH family studies demonstrated Mendelian inheritance of these loci and probability of identity values from population studies were 1/4,830 (African-American), 1/5,479 (U.S. Caucasian), and 1/3,443 (U.S. West Coast Hispanic). In all studies examining different body tissues and fluids, the expected genotypes were observed. Studies to determine and test the PCR reagent components and thermal cycling parameters demonstrated specificity, sensitivity, and balance over a wide range of conditions. Reliable results were obtained from DNA quantities as low as 0.25 ng. A variety of environmental studies were performed, as forensic samples are often exposed to different environmental conditions and substances which may degrade DNA or inhibit the amplification process. Highly degraded samples demonstrated that FGA was the first locus to become undetectable, followed by vWA, and then D3S1358; this is the expected pattern according to locus size. In studies of PCR inhibition, the pattern in which the loci became undetectable was different; FGA was the first locus to become undetectable, followed by D3S1358, and then vWA. Single versus multiple locus amplifications revealed no benefit to single locus analysis, even in cases of degradation or inhibition. The occurrence of preferential amplification was very rare, particularly in noncompromised, unmixed samples. Artifact peaks were not observed in any instance. Mixture studies confirmed the ability to detect mixed DNA samples and included the characterization of stutter and peak height ratios; the limit of detection was 1:10 for 1 ng total genomic DNA and 1:30 for 5 ng. DNA extracted from nonprobative case evidence was successfully amplified and genotyped. All such studies indicate that the AmpFISTR Blue PCR Amplification Kit will reproducibly yield specific and sensitive results.

Animals↗

An extragenic suppressor of the mitosis-defective bimD6 mutation of Aspergillus nidulans codes for a chromosome scaffold protein.

We previously identified a gene, bimD, that functions in chromosome segregation and contains sequences suggesting that it may be a DNA-binding protein. Two conditionally lethal mutations in bimD arrest with aberrant mitotic spindles at restrictive temperature. These spindles have one-third the normal number of microtubules, and the chromosomes never attach to the remaining microtubules. For this reason, we hypothesized that BIMD functioned in chromosome segregation, possibly as a component of the kinetochore. To identify other components that function with bimD, we conducted a screen for extragenic suppressors of the bimD5 and bimD6 mutations. We have isolated seven cold-sensitive extragenic suppressors of bimD6 heat sensitivity that represent three or possibly four separate sud genes. We have cloned one of the suppressor genes by complementation of the cold-sensitive phenotype of the sudA3 mutation. SUDA belongs to the DA-box protein family. DA-box proteins have been shown to function in chromosome structure and segregation. Thus bimD and the sud genes cooperatively function in chromosome segregation in Aspergillus nidulans.

Alleles↗

A novel phage lambda replacement Cre-lox vector that has automatic subcloning capabilities.

We have developed a novel phage lambda replacement cloning vector, lambda pAn. lambda pAn allows one to automatically subclone the insert as a plasmid using the Cre-loxP site-specific recombination system. This eliminates the need to subclone insert fragments and permits the rapid structural analysis of insert DNA. lambda pAn is similar to other phage lambda replacement vectors taking inserts ranging in size from 5 to 19 kb. We have placed the pyrG gene of Aspergillus nidulans on the vector as a nutritional selective marker for transformation. We have developed this vector as part of an overall plan to facilitate the cloning of dominant extragenic suppressor mutations from A. nidulans, but also know that it is a generally useful vector for the purposes of isolating genomic clones without the need to subclone from the phage lambda vector.

Aspergillus nidulans↗

The bimB3 mutation of Aspergillus nidulans uncouples DNA replication from the completion of mitosis.

A conditionally lethal mutation in the bimB gene of Aspergillus nidulans disrupts the normal regulatory patterns associated with mitotic events. This results in DNA replication in the absence of the completion of mitosis in the mutant at restrictive temperature. This defect yields large polyploid nuclei after several hours at restrictive temperature. The bimB gene has been cloned by genetic mapping and chromosome walking from the previously cloned amdS gene. The cloned DNA complements the temperature-sensitive recessive bimB3 mutation. Sequence analysis of overlapping complementary DNA clones for bimB predicts a polypeptide of 2,068 amino acids. The predicted polypeptide of 227,958 Da is shown to have a carboxyl-terminal region similar to those of the budding yeast ESP1 and fission yeast cut1+ genes. In contrast these genes exhibit no other regions of similarity to one another. The conserved domain in these three proteins and the similarity of the terminal mutant phenotypes for these genes are suggestive of a conserved function for this domain in each of the predicted polypeptides. We also present evidence for a second gene in the genome of A. nidulans which also has this conserved carboxyl-terminal region, suggesting that bimB, ESP1, and cut1+ may be members of a small gene family.

Amino Acid Sequence↗

The significance of portal vein gas in necrotizing enterocolitis.

To assess the significance of the presence of portal vein gas (PVG) in necrotizing enterocolitis (NEC), a retrospective study of all cases of NEC seen at Grady Memorial Hospital between July 1980 and June 1984 was conducted. Infants with PVG were compared with those without PVG with respect to clinical presentation, treatment, and outcome. There was no significant difference between the two groups in birth weight, Apgar scores, or the age of onset of NEC. All patients received standard medical therapy unless they developed pneumoperitoneum, had a positive paracentesis, or deteriorated in spite of maximal medical treatment, in which case they had surgery. Of 97 infants with "definite" NEC, 55 (56%) required surgery. Twenty-one patients (22% of the total) had PVG and 17 (81%) of them required surgery. Seventy-six patients (78% of total) did not have PVG and only 38 (50%) of them required surgery (P = 0.011). Five (29%) of 17 infants with PVG had nearly total intestinal necrosis compared with only five (13%, P = 0.25) of 38 infants without PVG. Patients with PVG had a lower overall survival rate (62% vs 88%, P = 0.009), medical survival rate (75% vs 97%, P = 0.184), and surgical survival rate (59% vs 79%, P = 0.19) than patients without PVG. Infants weighing less than 1000 grams fared worse regardless of the presence or absence of PVG. Portal vein gas is an ominous prognostic sign. It signals a greater likelihood for surgical intervention, a more extensive bowel involvement, and a significantly lower survival when compared to patients with NEC who do not have PVG.

Enterocolitis, Pseudomembranous↗

The role of host factors in an outbreak of necrotizing enterocolitis.

During an outbreak investigation of necrotizing enterocolitis (NEC) in a neonatal intensive care unit, we identified nine definite and six suspected cases of NEC on the basis of histopathologic, clinical, and roentgenographic findings. Neonates of low birth weight (less than 1,250 g) had the highest incidence of NEC, supporting a role for prematurity in this disease. Patients with definite NEC and those with severe clinical features had significantly lower birth weights and postconception ages (gestational age at birth plus postnatal age at onset of NEC) than the patients with suspected NEC. In a case-control study using birth weight-matched control subjects, maternal toxemia was identified as a possible protective factor for NEC. To our knowledge, this is the first report of the relationship between NEC disease severity and postconception age. These findings also suggest that toxemia may be an important protective factor in NEC and should be examined in subsequent studies.

Disease Outbreaks↗

The degradation of [14C]molinate in soil under flooded and nonflooded conditions.

The degradation of [14C]molinate in soil under flooded and nonflooded conditions was investigated. In laboratory studies, 50 percent of the applied molinate was lost in 3 weeks under moist soil conditions, while under flooded conditions, dissipation was reduced to 50 percent loss in 10 weeks. Analysis for molinate and its degradation products in the soil and flood water showed that under flooded conditions very little breakdown of molinate occurred, and volatilization was the primary mode of dissipation. However, under nonflooded conditions, hydroxylation of the azepine ring and further oxidation to the respective ketones occurs. Oxidation to form the sulfoxide, cleavage to yield the imine, and acetylation of the imine are also proposed. Other pathways appear to involve desethylation to produce a free thiocarbamic acid derivative followed by S-methylation as well as carboxylation of the S-ethyl group.

Azepines↗

Weight locus of control and weight-related attitudes and behaviors in an overweight population.

Rotter's [Psychol. Monogr. 80 (1966)] construct of internal-external control of reinforcement led to the conceptualization of locus of control as a personality construct that can be used to predict behavior. More specific measures of locus of control in particular behavioral domains have followed. In the present study, the Weight Locus of Control Scale (WLOC) was used to predict weight-related attitudes and behaviors of overweight individuals, as well as their responses to health education materials (HEM) on weight loss. The WLOC scores predicted responses to baseline weight-related measures such as etiology of obesity, confidence in weight loss behaviors, and behavioral intention. In addition, WLOC scores predicted participants' reactions to the HEM, as well as the actual number of weight loss ideas from the HEM that the participants tried by the 1-month follow-up assessment. The results are discussed in terms of the validity of the WLOC and implications for future development of effective HEM.

Adult↗

Understanding the effects of printed health education materials: which features lead to which outcomes?

Printed health education materials (HEMs) are widely used to increase awareness and knowledge, change attitudes and beliefs, and help individuals adopt and maintain healthy lifestyle behaviors. While much of the contemporary research and development of persuasive communication is based on McGuire's input/output model, to date few studies have compared the impact of a large set of inputs across a comprehensive set of the 12 outputs. We examined the effects of printed HEMs on weight loss on the cognitive, affective, and behavioral responses of 198 overweight adults. Participants were recruited via a newspaper advertisement and were randomly assigned to review one of three HEMs. Participants were interviewed and asked to complete a series of questionnaires both before and after viewing the HEMs. Regression analyses were conducted to identify the input characteristics associated with success at each of the output steps. The results revealed attractiveness, encouragement, level of information, and application to one's life were significantly associated with early steps (attention, liking, and understanding) as well as some of the mediating steps (recalling, keeping, and rereading HEMs). Later steps, such as intention to change behavior and show others, were associated with readiness to change, self-efficacy, and perceived application to one's life. Behavior change was more likely for those who received tailored materials and those who had higher self-efficacy. These results provide useful direction for the use of computers in tailoring the content of HEMs and the development of effective communication of health information on weight loss.

Body Mass Index↗