Biomedical subjects

C Hayward

Publications and source records attributed to C Hayward.

At least 19 recordsLinked to original sources

PubMed2001

Effects of storage solutions on in vitro vasoreactivity of radial artery conduits.

OBJECTIVES: Surgical preparation of coronary conduits for coronary artery bypass grafting may affect their early and long-term patency; one mechanism may involve endothelial damage. We investigated the effect of 3 commonly used solutions-Ringer's solution, normal saline solution, and heparinized whole blood-on in vitro endothelial and contractile functions of the human radial artery. METHODS: Radial artery segments were harvested, cut into 3-mm rings, and stored in unoxygenated Ringer's solution, normal saline solution, or heparinized whole blood for 45 minutes. Rings stored in Krebs solution were used as controls. The rings were then mounted and stretched to an optimal resting tension in oxygenated Krebs solution at 37 degrees C. Contraction responses to potassium, norepinephrine, and serotonin and relaxation responses to acetylcholine, verapamil, and nitroprusside were evaluated. RESULTS: Fifty-six radial artery ring segments from 14 patients (n = 7 rings for each contraction-relaxation curve) were studied. Equilibrated resting tension was 9.6 +/- 0.3 mN (5.9 +/- 0.2 g), and resting internal circumference was 6.4 +/- 0.2 mm. Absolute maximum contraction to potassium was significantly less in rings stored in normal saline solution than in rings stored in control solution (10.7 +/- 0.6 g vs 14.5 +/- 0.6 g, P <.01; 95% confidence intervals, 0.9-6.9). There was no difference in the contraction to norepinephrine (P =.11) and serotonin (P =.25) among the 3 solutions compared with the control solution. Rings stored in heparinized whole blood had significantly greater endothelium-dependent relaxation to acetylcholine (P <.007), whereas those stored in normal saline solution had reduced responses. Endothelium-independent relaxation to verapamil and nitroprusside were similar among the 3 solutions. CONCLUSION: Heparinized whole blood is a better physiologic medium for preservation of radial artery endothelial and contractile functions during storage before grafting.

Acetylcholine↗

PubMed2000

Can discography cause long-term back symptoms in previously asymptomatic subjects?

STUDY DESIGN: A prospective controlled study of patients without low back pain observed after experimental lumbar discography. OBJECTIVES: To determine whether discography may cause long-term low back symptoms in selected patients. BACKGROUND: Lumbar discography is generally considered safe, although controversial, with few complications. There is little information on long-term follow-up of asymptomatic patients after experimental discography. METHODS: Twenty-six patients without pre-existing low back pain were observed for 1 year after lumbar discography to determine the effects of lumbar discography in three experimental groups: 10 patients who had remote cervical spine surgery with excellent results (pain-free group); 10 patients who had the same surgery with poor results (chronic pain group); and 6 patients who had primary somatization disorders. Two control groups were also observed: a group of patients with somatization disorder who were similarly evaluated but without discography, a group of patients with low back pain observed for 1 year after discography without surgery. RESULTS: In the three experimental groups (no back pain before discography) no subject with normal psychometric testing had persistent pain after discography (0/11), whereas 6 (40%) of 15 with abnormal psychometric test results reported significant new low back pain. None of the pain-free group (0/10), 20% of the chronic neck pain group (2/10), and 66% of the somatization group (4/6) continued to have significant back pain 1 year after injection. Psychological testing and occupational disability strongly predicted continued pain after discography. The control groups had no significant change in low back symptomatology during the year of observation. CONCLUSION: Discography in a subject group without low back pain but with significant emotional and chronic pain problems may result in reports of significant back pain for at least 1 year after injection. Subjects with normal psychometric test results had no reports of significant long-term back pain after discography.

Adult↗

PubMed2000

The rates of false-positive lumbar discography in select patients without low back symptoms.

STUDY DESIGN: Experimental disc injections in subjects with no history of low back symptoms. OBJECTIVE: To determine in an experimental setting the relative pain response and pain-related behavior in selected subjects without a history of low back pain undergoing lumbar discography. This study aimed to select a study population that more closely represented patients undergoing discography in clinical practice. SUMMARY OF BACKGROUND DATA: Previous work has shown that in young, healthy men with little degenerative disc disease and no history of low back problems, discographic injections usually did not cause significant pain. This group differed from the patients who usually undergo discographic evaluation in clinical practice. Most clinical patients are older, have significant degenerative disc disease, have behavioral changes associated with chronic pain, and often have confounding psychosocial troubles. The authors undertook to study discography in subjects without low back pain but with clinical profiles similar to patients undergoing discography in clinical practice. METHODS: Twenty-six individuals, mean age 43 years, with no history of low back pain had lumber discography according to the strict protocol of Walsh et al. Of these, 10 were pain-free; 10 had chronic neck and arm pain, but no low back symptoms; and 6 had primary somatization disorders without low back symptoms.- RESULTS: Significant positive pain response and pain-related behavior with discography were found in 10% of the pain-free group, in 40% of the chronic cervical pain group, and in 83% of the somatization disorder group completing the injections. Twenty-four subjects had negative control discs. Discs with annular disruption were more likely to be painful on injection, particularly in those individuals with ongoing compensation issues, chronic pain, or abnormal psychological testing.- CONCLUSION: If strict criteria are applied, the rate of false-positive discography may be low in subjects with normal psychometric profiles and without chronic pain. Significantly painful injections were very common in subjects with annular disruption and chronic pain or abnormal psychometric testing.

Adult↗

PubMed2000

Molecular detection of Gluconacetobacter sacchari associated with the pink sugarcane mealybug Saccharicoccus sacchari (Cockerell) and the sugarcane leaf sheath microenvironment by FISH and PCR.

Molecular tools for the detection of the newly described acetic acid bacterium Gluconacetobacter sacchari from the pink sugarcane mealybug, Saccharicoccus sacchari Cockerell (Homiptera: Pseudococcidae), and in the sugarcane leaf sheath microenvironment were developed. G. sacchari specific 16S rRNA-targeted oligonucleotide primers were designed and used in PCR amplification of G. sacchari DNA directly from mealybugs, and in a nested PCR to detect low numbers of the bacteria from sugarcane leaf sheath fluid and cane internode scrapings. A sensitivity level of detection of 40-400 cells/reaction was obtained using PCR from exponentially grown bacterial cultures and of 1-10 cells in cane internode scrapings and leaf sheath fluid samples using nested PCR. The specificity of the primer set was demonstrated by the lack of amplification product formation in PCR by closely related acetic acid bacteria, including Gluconacetobacter liquefaciens, and Gluconacetobacter diazotrophicus. A Cy3 labeled probe for G. sacchari was designed and shown to be specific for the species. Investigation of the mealybug microenvironment by whole cell fluorescent in situ hybridization revealed that G. sacchari appears to represent only a minor proportion of the population of the microbiota in the mealybugs tested. This study has shown the usefulness of 16S rRNA-based molecular tools in the identification and detection of G. sacchari from environmental samples and will allow these tools to be used in further ecological research.

Journal Article↗

PubMed2000

Partial sequencing of the hrpB and endoglucanase genes confirms and expands the known diversity within the Ralstonia solanacearum species complex.

We determined partial hrpB and endoglucanase genes sequences for 30 strains of Ralstonia solanacearum and one strain of the blood disease bacterium (BDB), a close relative of Ralstonia solanacearum. Sequence comparisons showed high levels of variability within these two regions of the genome involved in pathogenicity. Phylogenetic analysis based upon sequence comparisons of these two regions revealed three major clusters comprising all Ralstonia solanacearum isolates, the BDB strain constituted a phylogenetically distinct entity. Cluster 1 and cluster 2 corresponded to the previously defined divisions 1 and 2 of Ralstonia solanacearum. Moreover, two subclusters could be identified within cluster 2. The last cluster, designated cluster 3 in this study, included biovar 1 and N2 strains originating from Africa. This recently described group of strains was confirmed to be clearly different from the other strains suggesting a separate evolution from those of both divisions 1 and 2.

Africa↗

PubMed2000

Predictors of panic attacks in adolescents.

OBJECTIVE: To identify risk factors for onset of panic attacks in adolescents, a prospective cohort design was used to evaluate the following risk factors: negative affectivity, female sex, anxiety sensitivity, and childhood separation anxiety disorder. These risk factors were also evaluated for predicting onset of major depression to test their specificity. METHOD: The sample consisted of 2,365 high school students assessed over a 4-year period. Assessments included self-report questionnaires and structured clinical interviews. Cox proportional hazards models were used to evaluate risk. RESULTS: Consistent with previous studies, prior major depression predicted onset of panic attacks and a history of panic attacks predicted onset of major depression. After adjusting for the effects of prior major depression, negative affectivity and anxiety sensitivity, but not female sex or childhood separation anxiety disorder, predicted onset of 4-symptom panic attacks. However, female sex and negative affectivity but not anxiety sensitivity or childhood separation anxiety disorder predicted onset of major depression after adjustment for the effects of prior panic attacks. CONCLUSION: Negative affectivity appears to be a nonspecific risk factor for panic attacks and major depression, whereas anxiety sensitivity appears to be a specific factor that increases the risk for 4-symptom panic attacks in adolescents.

Adolescent↗

PubMed2000

Cognitive-behavioral group therapy for social phobia in female adolescents: results of a pilot study.

OBJECTIVES: To examine the efficacy of cognitive-behavioral group therapy for adolescents (CBGT-A) in females with social phobia and the effect of this treatment on the risk for major depression. METHOD: Female adolescents with social phobia (N = 35) were randomly assigned to treatment (n = 12) or no treatment (n = 23) groups. Assessments were conducted at baseline, after treatment, and at a 1-year follow-up. RESULTS: Eleven subjects completed treatment. Sixteen weeks of treatment produced a significant improvement in interference and reduction in symptoms of social anxiety. There was a significant reduction in the number of subjects meeting DSM-IV criteria for social phobia in the CBGT-A versus the untreated group; however, at the 1-year follow-up there were no significant differences by treatment condition. There was also suggestive evidence that treatment of social phobia lowers the risk for relapse of major depression among those with a history of major depression. Combining social phobia and major depression as the outcome produced more robust treatment effects in the 1-year follow-up. CONCLUSIONS: This pilot study provides evidence for a moderate short-term effect of CBGT-A for treating female adolescents suffering from social phobia and indicates that treatment of social phobia may result in a reduction of major depression.

Adolescent↗

PubMed2000

Gyrodactylus anguillae (Monogenea: Gyrodactylidae) from anguillid eels (Anguilla australis and Anguilla reinhardtii) in Australia: a native or an exotic?

A species of Gyrodactylus collected from 2 species of anguillid eels (Anguilla australis Richardson, 1841 and Anguilla reinhardtii Steindachner, 1867) from Australia is identified as Gyrodactylus anguillae Ergens, 1960. The morphology of sclerites of G. anguillae specimens from Australia is in accordance with previous descriptions of specimens collected from A. anguilla (Linnaeus, 1758) from Europe and A. anguilla imported into Japan. Gyrodactylus anguillae was previously thought to be a parasite specific to A. anguilla, an eel that is native to freshwater catchments throughout Europe. Information on eel translocations and host and parasite biology is reviewed and it is hypothesized that G. anguillae is a naturally occurring parasite in Australia and not an introduction.

Anguilla↗

PubMed2000

Body-image and eating disturbances predict onset of depression among female adolescents: a longitudinal study.

This study examined data from a 4-year school-based longitudinal study (n = 1,124), to test whether the increase in major depression that occurs among girls during adolescence may be partially explained by the body-image and eating disturbances that emerge after puberty. Elevated body dissatisfaction, dietary restraint, and bulimic symptoms at study entry predicted onset of subsequent depression among initially nondepressed youth in bivariate analyses controlling for initial depressive symptoms. Although the unique effect for body dissatisfaction was not significant in the multivariate model, this set of risk factors was able to fairly accurately foretell which girls would go on to develop major depression. Results were consistent with the assertion that the body-image- and eating-related risk factors that emerge after puberty might contribute to the elevated rates of depression for adolescent girls.

Adolescent↗

PubMed2000

Nicotine patch and paroxetine for smoking cessation.

Smokers (N = 224) were randomized to 1 of 3 groups: (a) transdermal system (TNS) + placebo; (b) TNS + paroxetine (20 mg); (c) TNS + paroxetine (40 mg). Assignment to treatment was double-blind. Nicotine patch (TNS) treatment was provided for 8 weeks; paroxetine or placebo was provided for 9 weeks. Abstinence rates at Weeks 4, 10, and 26 were as follows: (a) TNS + placebo: 45%, 36%, and 25%; (b) TNS + paroxetine (20 mg): 48%, 33%, and 21%; (c) TNS + paroxetine (40 mg): 57%, 39%, and 27%. The differences were not statistically significant. The combined treatment was more effective in reducing both craving and depression symptoms associated with smoking cessation. A subgroup analysis comparing compliant participants was also conducted. Abstinence rates at Weeks 4, 10, and 26 were as follows: (a) TNS + placebo: 46%, 35%, and 24%; (b) TNS + paroxetine (20 mg): 64%, 43%, and 33%; (c) TNS + paroxetine (40 mg): 74%, 51%, and 38%. The differences between paroxetine groups and placebo at Week 4 were statistically significant. Although paroxetine may add value to the current standard of care in excess of potential risk, more conclusive evidence is needed.

Administration, Cutaneous↗

PubMed1999

Molecular genetic analysis of the APEX nuclease gene in amyotrophic lateral sclerosis.

We analyzed genomic DNA from ALS patients for mutations in the apurinic/apyrimidinic endonuclease (APEX nuclease) gene. We identified three rare polymorphisms in the untranslated region of the gene and one common two-allele polymorphism (D148E). The allelic frequency D148E was significantly different in sporadic ALS patients compared with controls. A conserved amino acid change and a 4-base pair deletion were also identified in sporadic ALS patients. These data suggest that APEX nuclease may contribute to the etiology of ALS.

Adult↗

PubMed1999

Salivary cortisol levels in socially phobic adolescent girls.

Anxiety disorders such as social phobia (SP) often have their onset during adolescence and frequently precede the onset of major depression. Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis is well-documented in major depression. Consequently, there is considerable interest in HPA function in anxiety disorders. We examined salivary cortisol levels in 27 SP adolescent girls and 21 matched controls during normal daily activities, and immediately before and after a modified Trier Social Stress Test (TSST). Both SP subjects and controls showed significant elevations in cortisol levels prior to the TSST, and prior to attending school. These results suggest that salivary cortisol is a sensitive measure of anticipatory anxiety, but we failed to find significant differences between SP subjects and controls.

Adolescent↗

PubMed1999

Aggregation and species coexistence of ectoparasites of marine fishes.

Interspecific interaction may lead to species exclusion but there are several ways in which species can coexist. One way is by reducing the overall intensity of competition via aggregated utilisation of fragmented resources. Known as the 'aggregation model of coexistence', this system assumes saturation and an equilibrium number of species per community. In this study we tested the effects of interspecific aggregation on the level of intraspecific aggregation among ectoparasites of marine fishes (36 communities of gill and head ectoparasite species). If parasite species are distributed in a way that interspecific aggregation is reduced relative to intraspecific aggregation then species coexistence is facilitated. We found a positive relationship between parasite species richness and fish body size, controlling for host phylogeny. A positive relationship between infracommunity species richness and total parasite species richness was also found, providing no evidence for saturation. This result supports the view that infracommunities of parasites are not saturated by local parasite residents. The observed lack of saturation implies that we are far from a full exploitation of the fish resource by parasites. Ectoparasites were aggregated at both population and species levels. However, only half of the ectoparasite communities were dominated by negative interspecific aggregation. We found that infracommunity parasite species richness was positively correlated with the level of intraspecific aggregation versus interspecific aggregation. This means that intraspecific aggregation increases compared with interspecific aggregation when total parasite species richness increases, controlling fish size and phylogeny. This supports one assumption of the 'aggregation model of coexistence', which predicts that interspecific interactions are reduced relative to intraspecific interactions, facilitating species coexistence.

Animals↗

PubMed1999

Gender differences in correlates of depressive symptoms in adolescents.

PURPOSE: To determine: (a) what demographic and psychosocial factors are associated with elevated levels of depressive symptoms in adolescence; (b) whether girls and boys show different profiles of correlates and probable risk factors for depressive symptoms; and (c) what the implications are of these results for future research directions and policy decisions. METHODS: Using a nationally representative sample of adolescent school students in Grades 5-12, the Commonwealth Fund Adolescent Health Survey assessed depressive symptoms as well as a number of variables posited to be risk factors and correlates of depression. RESULTS: Depressive symptoms were found to differ by gender, age, socioeconomic status, and ethnicity. In addition, life stress, social support, and coping were associated with depressive symptoms. Importantly, stress and social support appear to be particularly salient aspects of depression among girls. Both physical and sexual abuse were strongly linked with depression for both boys and girls, with sexual abuse having a stronger impact among boys. Finally, high levels of depressive symptoms were associated with increased use of both mental and physical health care resources among boys and girls. CONCLUSIONS: The correlates of depression in this adolescent sample closely resemble those seen in adult samples, including demographic and psychosocial variables. Some psychosocial variables, such as stress and social support, may have a greater impact on depressive symptoms for girls than for boys. Results of this study also have important implications for the health care system, given that higher levels of depressive symptoms were found to be associated with greater utilization of physical health care resources.

Adaptation, Psychological↗

PubMed1999

Ethnic differences in the association between pubertal status and symptoms of depression in adolescent girls.

PURPOSE: To examine the importance of chronologic age versus pubertal status in predicting adolescent girls' depressive symptoms in different ethnic groups. METHODS: A national probability sample was used to obtain a representative cohort of 3216 adolescents, 5th through 8th grades. Subjects completed a questionnaire, which included a modified version of the Children's Depression Inventory (CDI) and an assessment of timing of menarche. RESULTS: Among Caucasians, post-menarcheal adolescent girls had higher depression scores than did same-aged pre-menarcheal girls. Boys and pre-menarcheal girls had similar depression scores in most age groups. Among African-Americans and Hispanics, there were no menarche-associated differences in depressive symptoms. CONCLUSION: In early adolescence pubertal status is a better predictor of depressive symptoms than chronological age in Caucasian, but not African-American or Hispanic girls.

Adolescent↗

PubMed1999

Naturalistic weight-reduction efforts prospectively predict growth in relative weight and onset of obesity among female adolescents.

This study examined the prospective relations of naturalistic weight-reduction efforts to growth in relative weight and onset of obesity with data from a community study of female adolescents (N = 692). Initial self-labeled dieting, appetite suppressant/laxative use, incidental exercise, vomiting for weight-control purposes, and binge eating predicted elevated growth in relative weight over the 4-year period. Dietary restraint, self-labeled dieting, exercise for weight-control purposes, and appetite suppressant/laxative use predicted an increased risk for obesity onset. Data imply that the weight-reduction efforts reported by adolescents are more likely to result in weight gain than in weight loss and suggest the need to educate youth on more effective weight-control strategies.

Adolescent↗

PubMed1999

Phylogenetic relationships among members of the Comamonadaceae, and description of Delftia acidovorans (den Dooren de Jong 1926 and Tamaoka et al. 1987) gen. nov., comb. nov.

The phylogenetic relationships among members of the family Comamonadaceae and several unclassified strains were studied by direct sequencing of their PCR-amplified 16S rRNA genes. Based on the 16S rRNA gene sequence analysis, members of the family formed a coherent group. The closest relatives are species of the Rubrivivax sub-group: Leptothrix discophora, Ideonella dechloratans and Rubrivivax gelatinosus. The genus Hydrogenophaga formed two subclusters, as did the species of Acidovorax, whereas the five species of the genus [Aquaspirillum] were polyphyletic. Comamonas acidovorans was phylogenetically distant from the type species of Comamonas, Comamonas terrigena. On the basis of this work and previous studies, Comamonas acidovorans is removed from the genus Comamonas and renamed as Delftia acidovorans gen. nov., comb. nov. Descriptions of the new genus Delftia and of the type species Delftia acidovorans, for which the type strain is ATCC 15668T, are presented.

DNA, Bacterial↗

PubMed1999

Description of Gluconacetobacter sacchari sp. nov., a new species of acetic acid bacterium isolated from the leaf sheath of sugar cane and from the pink sugar-cane mealy bug.

A new species of the genus Gluconacetobacter, for which the name Gluconacetobacter sacchari sp. nov. is proposed, was isolated from the leaf sheath of sugar cane and from the pink sugar-cane mealy bug, Saccharicoccus sacchari, found on sugar cane growing in Queensland and northern New South Wales, Australia. The nearest phylogenetic relatives in the alpha-subclass of the Proteobacteria are Gluconacetobacter liquefaciens and Gluconacetobacter diazotrophicus, which have 98.8-99.3% and 97.9-98.5% 16S rDNA sequence similarity, respectively, to members of Gluconacetobacter sacchari. On the basis of the phylogenetic positioning of the strains, DNA reassociation studies, phenotypic tests and the presence of the Q10 ubiquinone, this new species was assigned to the genus Gluconacetobacter. No single phenotypic characteristic is unique to the species, but the species can be differentiated phenotypically from closely related members of the acetic acid bacteria by growth in the presence of 0.01% malachite green, growth on 30% glucose, an inability to fix nitrogen and an inability to grow with the L-amino acids asparagine, glycine, glutamine, threonine and tryptophan when D-mannitol was supplied as the sole carbon and energy source. The type strain of this species is strain SRI 1794T (= DSM 12717T).

Acetobacteraceae↗