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Biomedical subjects

D Ward

Publications and source records attributed to D Ward.

At least 73 records · Page 4Linked to original sources
PubMed1996

Predictors of alcohol use among rural adolescents.

There is increasing evidence that alcohol use is becoming more common during childhood and early adolescence. However, little is known about alcohol use among rural youths. This article reports a study of alcohol use among 367 fifth-grade students in two rural South Carolina school districts. More than one third (n = 131) of the fifth graders reported having used alcohol. Of these, 34 percent (n = 44) reported drinking during the previous month; 8 percent had been intoxicated during the previous two months; and 54 percent reported drinking in the home with or without parental approval. Logistic regression analysis was used to determine the predictors of alcohol use by fifth graders. The results indicated that gender (OR = 2.82), mother's alcohol use (OR = 1.86), father's alcohol use (OR = 2.13), and smoking (OR = 8.30) were significantly associated with alcohol use. The findings suggest that prevention programs address cigarette smoking and drinking behaviors of parents to reduce alcohol use and the acquisition of other health compromising behavior by youths. Early intervention approaches must go beyond the schools and target families as well as community populations.

Adolescent↗
PubMed1996

Influence of reduced carotid body drive during sustained hypoxia on hypoxic depression of ventilation in humans.

To evaluate whether the intact hypoxic drive from the carotid bodies during sustained hypoxia is required for the generation of hypoxic depression of ventilation (VE), 16 volunteers were exposed to two consecutive periods of isocapnic hypoxia (first period 20 min; second period 5 min; end-tidal PO2 45 Torr) separated by 6 min of normoxia. In study A, saline was given. In study B, 3 micrograms.kg-1.min-1 i.v. dopamine (DA), a carotid body inhibitor, was given during the first hypoxic exposure followed by saline during normoxia and the second hypoxic exposure. In study C, 20 min of normoxia with DA preceded 6 min of normoxia and 5 min of hypoxia without DA. The first peak hypoxic VE (PHV) in study A was approximately 100% above normoxic VE. After 20 min of hypoxia, VE declined to 60% above normoxic VE. The second PHV in study A was only 60% of the first PHV. We relate this delayed recovery from hypoxia to "ongoing" effects of hypoxic depression. During DA infusion, the changes in VE due to sustained hypoxia were insignificant (study B). The second PHV in study B was not different from the PHV after air breathing in studies A and C. This indicates that the recovery from sustained hypoxia with a suppressed carotid body drive was complete within 6 min. Our results show that despite central hypoxia the absence of ventilatory changes during 20 min of isocapnic hypoxia due to intravenous DA prevented the generation of central hypoxic depression and the depression of a subsequent hypoxic response.

Adult↗
PubMed1995

Localization of the human achaete-scute homolog gene (ASCL1) distal to phenylalanine hydroxylase (PAH) and proximal to tumor rejection antigen (TRA1) on chromosome 12q22-q23.

ASCL1, the human achaete-scute homolog, is a helix-loop-helix transcription factor that was previously assigned to chromosome 12 using a rodent-human somatic hybrid panel. We now placed this gene on a yeast artificial chromosome contig encompassing position 119 cM of the Généthon genetic map between the two genes phenylalanine hydroxylase (PAH) and tumor rejection antigen 1 (TRA1). We also localized ASCL1 in the 12q22-q23 cytogenetic interval by using fluorescence in situ hybridization.

Antigens, Neoplasm↗
PubMed1995

Physical mapping of the human ELA1 gene between D12S361 and D12S347 on chromosome 12q13.

ELA1, the pancreatic elastase 1 gene, is conserved in mammalian genomes. ELA1 was previously mapped to chromosome 12 using a panel of mouse-human somatic cell hybrids. We now report the physical and cytogenetic localization of the ELA1 gene. On the physical map, ELA1 is adjacent to the polymorphic marker AFMa283yg1 and between D12S361 and D12S347. Using fluorescence in situ hybridization, we determined that ELA1 maps to 12q13.

Animals↗
PubMed1995

Interleukin-1 and oncostatin M in combination promote the release of collagen fragments from bovine nasal cartilage in culture.

Interleukin-1 (IL-1) and Oncostatin M (OM) induce a rapid and reproducible release of proteoglycan and collagen fragments from bovine nasal cartilage in culture. Over 90% of the total collagen was released by day 14 compared to a variable release with IL-1 alone. This release was accompanied by the appearance of collagenolytic activity in the medium that cleaved collagen specifically at the one quarter/three quarter position. Tissue inhibitor of metalloproteinases (TIMP-1) activity was low or absent in media from resorbing tissue. The breakdown of cartilage collagen could be prevented by the addition of BB94, a specific matrix metalloproteinase (MMP) inhibitor. These results suggest that T-cell/macrophage products within inflammed joints can interact with pro-inflammatory cytokines and lead to the rapid destruction of connective tissue collagen.

Animals↗
PubMed1995

Primary structure, functional expression, and chromosomal localization of the bumetanide-sensitive Na-K-Cl cotransporter in human colon.

By moving chloride into epithelial cells, the Na-K-Cl cotransporter aids transcellular movement of chloride across both secretory and absorptive epithelia. Using cDNA probes from the recently identified elasmobranch secretory Na-K-Cl cotransporter (sNKCC1) (Xu, J. C., Lytle, C. Zhu, T. T., Payne, J. A., Benz, E., and Forbush, B., III (1994) Proc. Natl. Acad. Sci. 91, 2201-2205), we have identified the human homologue. By screening cDNA libraries of a human colonic carcinoma line, T84 cell, we identified a sequence of 4115 bases from overlapping clones. The deduced protein is 1212 amino acids in length, and analysis of the primary structure indicates 12 transmembrane segments. The primary structure is 74% identical to sNKCC1, 91% identical to a mouse Na-K-Cl cotransporter (mNKCC1), 58% identical to rabbit and rat renal Na-K-Cl cotransporters (NKCC2), and 43% identical to the thiazide-sensitive Na-Cl cotransporters from flounder urinary bladder and rat kidney. Similar to sNKCC1 and mNKCC1, the 5'-end of the human colonic cotransporter is rich in G + C content. Interestingly, a triple repeat (GCG)7 occurs within the 5'-coding region and contributes to a large alanine repeat (Ala15). Two sites for N-linked glycosylation are predicted on an extracellular loop between putative transmembrane segments 7 and 8. A single potential site for phosphorylation by protein kinase A is present in the predicted cytoplasmic C-terminal domain. Northern blot analysis revealed a 7.4-7.5-kilobase transcript in T84 cells and shark rectal gland and a approximately 7.2-kilobase transcript in mammalian colon, kidney, lung, and stomach. Metaphase spreads from lymphocytes were probed with biotin-labeled cDNA and avidin fluorescein (the cotransporter gene was localized to human chromosome 5 at position 5q23.3). Human embryonic kidney cells stably transfected with the full-length cDNA expressed a approximately 170-kDa protein recognized by anti-cotransporter antibodies. Following treatment with N-glycosidase F, the molecular mass of the expressed protein was similar to that predicted for the core protein from the cDNA sequence (132-kDa) and identical to that of deglycosylated T84 cotransporter (approximately 135-kDa). The stably transfected cells exhibited a approximately 15-fold greater bumetanide-sensitive 86Rb influx than control cells, and this flux required external sodium and chloride. Flux kinetics were consistent with an electroneutral cotransport of 1Na:1K:2Cl. Preincubation in chloride-free media was necessary to activate fully the expressed cotransporter, suggesting a [Cl]-dependent regulatory mechanism.

Amino Acid Sequence↗
PubMed1995

Low platelet mitochondrial complex I and complex II/III activity in early untreated Parkinson's disease.

Following the discovery of inhibition of electron transport complex 1 by the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), which produces a parkinsonian syndrome in humans, monkeys, and mice, several laboratories have reported abnormalities of complex I and other electron transport complexes (ETCs) in various tissues from patients with Parkinson's disease (PD). Criticism of the significance of these findings in the etiology of PD has centered on whether drug treatments or the debilitation of the disease process itself produced the low ETC activities. We present results from a blinded study of platelet mitochondrial ETC activities in 18 early untreated PD patients and 18 age- and sex-matched controls and in 13 spousal controls. Lower complex I activity in platelet mitochondria of PD patients was seen in early untreated disease and thus cannot be due to debilitation or drug therapy. Home environmental factors seem an unlikely explanation for the reduced complex I activity in PD patients but have not been excluded. Complex II/III activity was also reduced by 20% in PD compared with age-/sex-matched controls. The low complex I and II/III activities in platelet mitochondria appear to be related to the etiology of PD.

Adult↗
PubMed1995

Improved outcome by identification of high-risk nonocclusive mesenteric ischemia, aggressive reexploration, and delayed anastomosis.

BACKGROUND: The factors associated with outcome of patients with nonocclusive mesenteric ischemia are poorly defined. METHODS: Over a 7-year period, 34 consecutive patients with nonocclusive mesenteric ischemia were identified. RESULTS: The mean age of the study patients was 63 years (range 31 to 94); 21 of 34 (62%) were men. The mean delay in diagnosis was 31 hours (range 7 hours to 6 days). Seven of 34 (21%) underwent preoperative visceral arteriography. Two of these 7 required surgery, and both died as a result of intestinal infarction. The remaining 27 had the diagnosis made at celiotomy. Among the 29 who were explored, 16 of 29 (55%) had intestinal infarction. Twenty-one of 29 (72%) had segmental bowel injury whereas 8 of 29 (28%) had massive injury. Among those with segmental infarction, primary anastomosis was performed in 12 of 21 patients (57%); 5 of the 12 (42%) died. Nine of 21 patients (43%) underwent delayed anastomosis; 2 of the 9 (22%) died. No patient with massive injury underwent primary anastomosis. Second-look laparotomy was performed on 22 of 29 (76%). Eleven of those 22 (50%) had a further bowel resection. Overall, 16 of 29 (55%) who underwent surgery for nonocclusive mesenteric ischemia are alive. CONCLUSIONS: Improved survival from nonocclusive mesenteric ischemia is dependent upon the identification of high-risk groups, aggressive reexploration, and delayed intestinal anastomosis.

Acute Disease↗
PubMed1995

Parents' attitudes and beliefs about HIV/AIDS prevention with condom availability in New York City public high schools.

In 1991, the New York City Board of Education expanded HIV/AIDS education to include condom availability in every public high school. The evaluation was designed to examine the impact of the program on students and monitor changes in parent's knowledge, attitudes, and beliefs. Findings are reported from the first wave of data from the parent survey, 716 parents from 12 randomly chosen NYC high schools and 81 parents from 12 focus groups held at six of the schools. Sixty-nine percent of parents believed students should be able to receive condoms at school, although nearly half felt they should have the right to keep their children from doing so. Most believed making condoms available would result in safer sex practices among students who were sexually active. Data suggest parents support the school's role in reducing HIV/AIDS transmission among adolescents and believe making condoms available represents an acceptable component of an HIV/AIDS prevention program.

Adolescent↗
PubMed1994

IRE-bubble PCR: a rapid method for efficient and representative amplification of human genomic DNA sequences from complex sources.

A significant issue in the analysis of any genomic DNA segment is the generation of a unique set of short single-copy sequences that are representative of that region. In this report we describe a novel technique, IRE-bubble PCR, which was designed to amplify the human DNA content of somatic cell hybrids, YACs, cosmids, and lambda phage and result in greater complexity and representation than standard inter-IRE PCR. Here we demonstrate that IRE-bubble PCR is species specific and that it results in the generation of a product that is at least 10-fold more complex and representative than that produced by standard inter-IRE PCR. In addition, we have addressed the factors that contribute to the representation of the IRE-bubble PCR product and show how they may be used to further increase the complexity of this reaction. Finally, we have illustrated how the complexity and distribution of products generated by IRE-bubble PCR can be exploited and applied to FISH mapping and "chromosome painting" as well as to the generation of STSs targeted to specific chromosomal or subchromosomal regions.

Animals↗
PubMed1994

Large human YACs constructed in a rad52 strain show a reduced rate of chimerism.

Current YAC libraries are plagued by a high frequency of chimeras--that is, clones containing fragments from multiple genomic regions. Chimeras are thought to arise largely through recombination in the yeast host cell. If so, the use of recombination-deficient yeast strains, such as rad52 mutants, might be expected to alleviate the problem. Here, we report the construction of megabase-sized human YACs in the rad52 strain MHY5201 and the determination of their rate of chimerism by fluorescence in situ hybridization analysis. Examination of 48 YACs showed a rate of chimerism of at most 8%, whereas YACs constructed in the wildtype host AB1380 showed a rate of about 50%. These results show that it is possible to significantly decrease the rate of YAC chimerism through the use of appropriate yeast host strains.

Base Sequence↗
PubMed1994

Organization of the human keratin type II gene cluster at 12q13.

Keratin proteins constitute intermediate filaments and are the major differentiation products of mammalian epithelial cells. The epithelial keratins are classified into two groups, type I and type II, and one member of each group is expressed in a given epithelial cell differentiation stage. Mutations in type I and type II keratin genes have now been implicated in three different human genetic disorders, epidermolysis bullosa simplex, epidermolytic hyperkeratosis, and epidermolytic palmoplantar keratoderma. Members of the type I keratins are mapped to human chromosome 17, and the type II keratin genes are mapped to chromosome 12. To understand the organization of the type II keratin genes on chromosome 12, we isolated several yeast artificial chromosomes carrying these keratin genes and examined them in detail. We show that eight already known type II keratin genes are located in a cluster at 12q13, and their relative organization reflects their evolutionary relationship. We also determined that a type I keratin gene, KRT18, is located next to its partner, KRT8, in this cluster. Careful examination of the cluster also revealed that there may be a number of additional keratin genes at this locus that have not been described previously.

Amino Acid Sequence↗
PubMed1994

Neutrophil dysfunction in end-stage renal failure: reduced response to priming by C5a.

We studied the effect of C5a pretreatment on phosphatidyl-inositol-4,5-bisphosphate (PIP2) hydrolysis and on the increase in peak and resting cytosolic calcium levels induced by C5a (0.1 and 10 nM) and/or N-formyl hexapeptide (FLPEP; 10 nM) in neutrophils isolated from patients with end-stage renal failure (ESRF) and those from healthy controls. We also investigated superoxide anion production under the same conditions using the fluorescent para-hydroxyphenylacetic acid assay. The hydrolysis of PIP2 induced by C5a or FLPEP alone was similar in neutrophils from patients with ESRF and in control cells. Likewise, pretreatment of patients' neutrophils with C5a prior to FLPEP did not affect hydrolysis or the increase in cytosolic calcium concentration as shown previously for control neutrophils. Resting calcium levels in both ESRF and control neutrophils, however, were significantly increased after priming with low C5a concentrations. After priming with low C5a, prior to FLPEP, there was also a significant increase in superoxide production. This increase was significantly lower in cells from uremic patients than in those from healthy controls. Our data suggest that priming-induced superoxide production in neutrophils is reduced in patients with ESRF.

Amino Acid Sequence↗