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Biomedical subjects

S Carroll

Publications and source records attributed to S Carroll.

At least 55 records · Page 3Linked to original sources
PubMed2000

Leisure time physical activity, cardiorespiratory fitness, and plasma fibrinogen concentrations in nonsmoking middle-aged men.

PURPOSE: The relationship of both leisure time physical activity and predicted maximum oxygen consumption (VO2max) with plasma fibrinogen concentration was examined within a cohort of employed middle-aged men. METHODS: Analyses were performed on a subsample of 635 nonsmoking men (46.7 +/- 7.7 yr) who completed a preventive medical assessment between 1992 and 1996. RESULTS: Among nonsmokers, mean age-adjusted fibrinogen concentration decreased significantly with higher physical activity index (PAL) categories and quartiles of predicted VO2max (mL x kg(-1) x min(-1)) (both P = 0.001). Mean age-adjusted plasma fibrinogen concentrations were significantly different (P < 0.05) between inactive and vigorous PAI groups and extreme quartiles of predicted VO2max (mL x kg(-1) x min(-1)). These relationships were no longer significant after adjustment for the confounding effect of other ischemic heart disease risk factors. Stepwise multiple regression analyses showed that age, sum of skinfolds, and blood leukocyte count were the strongest predictors of plasma fibrinogen concentration. CONCLUSION: These data do not confirm a significant independent association of both physical activity and predicted VO2max (mL x kg(-1) x min(-1)) with fibrinogen concentrations among nonsmoking middle-aged men of similar high social class.

Adult↗
PubMed2000

Metabolic clustering, physical activity and fitness in nonsmoking, middle-aged men.

PURPOSE: The relationship of both physical activity and predicted maximum oxygen consumption (VO2max) with the clustering of metabolic risk factors associated with the metabolic syndrome (MS) was examined within 711 employed middle-aged (46.9 +/- 7.8 yr) men. METHODS: Metabolic markers included fasting glucose, triglycerides, high-density lipoprotein cholesterol, blood pressure, and BMI, defined by highest risk quintiles or clinically relevant risk thresholds. RESULTS: The prevalence and age-adjusted odds ratios of all MS clusters were inversely graded across both higher physical activity index (PAI) and cardiorespiratory fitness (CRF) categories. The age-adjusted odds ratio for the clustering of clinically relevant metabolic markers was 0.60 (95% CI 0.22-1.22) for subjects in the occasional/light PAI, 0.32 (95% CI 0.12-0.82) for the moderate/moderately vigorous PAI, and 0.13 (95% CI 0.02-1.02) for the vigorous PAI when compared with subjects in the sedentary PAI (P < 0.05 for trend). The corresponding age-adjusted odds ratio was 0.28 (95% CI 0.14-0.57) for subjects in the moderate fitness category and 0.12 (95% CI 0.05-0.32) for the highest fitness category compared with those in the lowest fitness category (P < 0.001 for trend). Higher levels of physical activity or CRF were also associated with significantly lower age-adjusted odds ratios for the MS after exclusion of obesity in the MS definition. CONCLUSION: Overall, these cross-sectional results suggest that higher physical activity and predicted VO2max levels are associated with a decreased clustering of risk factors associated with the MS in middle-aged men of higher social class.

Adult↗
PubMed2000

An investigation of the early effects of manual lung hyperinflation in critically ill patients.

This prospective within-group multicentre study was designed to assess the safety and short-term effectiveness of manual lung hyperinflation in mechanically ventilated patients. Eighteen patients from the intensive care units of two tertiary institutions were included and acted as their own control. Manual lung hyperinflation treatment involved patient positioning (side-lying), suctioning and manual lung hyperinflation. Side-lying treatment involved patient positioning and suctioning alone. Patients received both treatments on the day of data collection. Results demonstrated significant improvement for static respiratory system compliance (P = 0.001) with manual lung hyperinflation treatment compared to side-lying treatment. Manual lung hyperinflation treatment also cleared a significantly greater wet weight of sputum (P = 0.039). There were no differences between manual lung hyperinflation and side-lying treatment for gas exchange (PaO2/FIO2 and PaCO2), mean arterial pressure or heart rate. In conclusion, total static respiratory system compliance and sputum clearance were improved by the addition of manual hyperinflation to a physiotherapy treatment of positioning and suctioning in mechanically ventilated patients without compromise to cardiovascular stability or gas exchange.

Adult↗
PubMed2000

Plasma viscosity, fibrinogen and the metabolic syndrome: effect of obesity and cardiorespiratory fitness.

The association between both plasma viscosity and fibrinogen concentration with clustering of metabolic risk markers was examined within a cross-sectional study of employed middle-aged men. Analyses were performed on a subsample of 629 non-smokers (46.7+/-7.8 years) without diabetes. The effect of obesity and cardiorespiratory fitness on these haemorheological parameters and their association with the metabolic syndrome was also investigated. The cohort was grouped by the number of metabolic markers present. Metabolic markers included high-density lipoprotein-cholesterol (<1.13 mmol/l), triglycerides (> or =1.805 mmol/l), glucose (> or =5.5 mmol/l) and diastolic blood pressure (> or =90 mm Hg). The age-adjusted odds ratio for hyperviscosity (> or =1.67 mPa/s) was 2.08 [95% confidence interval (CI), 1.06-4.05; P = 0.031] for the subjects with the metabolic syndrome (three or more metabolic markers) when compared with those with no metabolic abnormalities. The comparable age-adjusted odds ratio for hyperfibrinogenaemia (> or = 3.47 g/l) was non-significantly higher at 1.69 (95% CI, 0.87-3.27; P = 0.119). The mean age-adjusted plasma viscosity level and the prevalence of hyperviscosity increased significantly from 1.629 to 1.692 mPa/s (P = 0.0005) and from 21.0 to 36.0% with accumulating metabolic markers (P = 0.006). Plasma viscosity and fibrinogen concentration both increased with higher quartiles of skinfolds (P = 0.003 and P = 0.01, respectively) following adjustment for age, lipids and leucocyte count. Plasma viscosity was also significantly lower with higher levels of predicted maximum oxygen consumption (VO2max) (P = 0.0005). The odds ratio for hyperviscosity in subjects with the metabolic syndrome as compared with those with no metabolic markers was attenuated following adjustment for age, sum of skinfolds and predicted maximum oxygen consumption (VO2max) (1.44; 95% CI, 0.72-2.90; P = 0.307). These cross-sectional results suggest that plasma viscosity is associated with increased clustering of metabolic markers in middle-aged men of high socio-economic status. Obesity and poor cardiorespiratory fitness may be important in the development of haemorheological abnormalities associated with the metabolic syndrome.

Adult↗
PubMed1999

Ultrabithorax function in butterfly wings and the evolution of insect wing patterns.

BACKGROUND: . The morphological and functional evolution of appendages has played a critical role in animal evolution, but the developmental genetic mechanisms underlying appendage diversity are not understood. Given that homologous appendage development is controlled by the same Hox gene in different organisms, and that Hox genes are transcription factors, diversity may evolve from changes in the regulation of Hox target genes. Two impediments to understanding the role of Hox genes in morphological evolution have been the limited number of organisms in which Hox gene function can be studied and the paucity of known Hox-regulated target genes. We have therefore analyzed a butterfly homeotic mutant 'Hindsight', in which portions of the ventral hindwing pattern are transformed to ventral forewing identity, and we have compared the regulation of target genes by the Ultrabithorax (Ubx) gene product in Lepidopteran and Dipteran hindwings. RESULTS: . We show that Ubx gene expression is lost from patches of cells in developing Hindsight hindwings, correlating with changes in wing pigmentation, color pattern elements, and scale morphology. We use this mutant to study how regulation of target genes by Ubx protein differs between species. We find that several Ubx-regulated genes in the Drosophila haltere are not repressed by Ubx in butterfly hindwings, but that Distal-less (Dll) expression is regulated by Ubx in a unique manner in butterflies. CONCLUSIONS: . The morphological diversification of insect hindwings has involved the acquisition of different sets of target genes by Ubx in different lineages. Changes in Hox-regulated target gene sets are, in general, likely to underlie the morphological divergence of homologous structures between animals.

Animals↗
PubMed1999

Falls among healthy, community-dwelling, older women: a prospective study of frequency, circumstances, consequences and prediction accuracy.

OBJECTIVE: Most studies of falls among older people have focused on those with some degree of balance or mobility impairment. This study aimed to establish whether falls and associated injuries were a major problem among healthy, older women, whether there were some common features in the falls, and whether these falls could be accurately predicted. METHOD: Ninety-six healthy, active community-dwelling women in Melbourne, Australia, aged at least 70 years (mean 74.1 +/- 4.0) were initially measured on a comprehensive series of laboratory and clinical balance tests, gait, strength and psychometric measures. Subjects were monitored for falls events, circumstances and consequences by use of falls diaries and monthly phone calls. Baseline measures of clinical balance measures and gait were comparable to other studies reporting scores on these measures in samples of healthy older people. RESULTS: During the 12-month follow-up period, 49% of subjects fell, with 23% falling more than once; 9% suffered fractures as a result of their fall and 10% suffered strains or other moderate injuries. Many of the falls occurred during non-threatening activities such as walking, often under altered sensory or environmental conditions. Multivariate logistic regression identified gait symmetry and gait double support duration as the variables most strongly associated with prediction of multiple fallers. CONCLUSIONS: The results highlight that falls are a major problem among healthy active older women, and that targeted falls prevention programs are required for this group.

Accidental Falls↗
PubMed1999

Prolonged contraction-relaxation cycle of fast-twitch muscles in parvalbumin knockout mice.

The calcium-binding protein parvalbumin (PV) occurs at high concentrations in fast-contracting vertebrate muscle fibers. Its putative role in facilitating the rapid relaxation of mammalian fast-twitch muscle fibers by acting as a temporary buffer for Ca2+ is still controversial. We generated knockout mice for PV (PV -/-) and compared the Ca2+ transients and the dynamics of contraction of their muscles with those from heterozygous (PV +/-) and wild-type (WT) mice. In the muscles of PV-deficient mice, the decay of intracellular Ca2+ concentration ([Ca2+]i) after 20-ms stimulation was slower compared with WT mice and led to a prolongation of the time required to attain peak twitch tension and to an extension of the half-relaxation time. The integral [Ca2+]i in muscle fibers of PV -/- mice was higher and consequently the force generated during a single twitch was approximately 40% greater than in PV +/- and WT animals. Acceleration of the contraction-relaxation cycle of fast-twitch muscle fibers by PV may confer an advantage in the performance of rapid, phasic movements.

Animals↗
PubMed1999

Calcium transients in single fibers of low-frequency stimulated fast-twitch muscle of rat.

Ca(2+) transients were investigated in single fibers isolated from rat extensor digitorum longus muscles exposed to chronic low-frequency stimulation for different time periods up to 10 days. Approximately 2.5-fold increases in resting Ca(2+) concentration ([Ca(2+)]) were observed 2 h after stimulation onset and persisted throughout the stimulation period. The elevated [Ca(2+)] levels were in the range characteristic of slow-twitch fibers from soleus muscle. In addition, we noticed a transitory elevation of the integral [Ca(2+)] per pulse with a maximum ( approximately 5-fold) after 1 day. Steep decreases in rate constant of [Ca(2+)] decay could be explained by an immediate impairment of Ca(2+) uptake and, with longer stimulation periods, by an additional loss of cytosolic Ca(2+) binding capacity resulting from a decay in parvalbumin content. A partial recovery of the rate constant of [Ca(2+)] decay in 10-day stimulated muscle could be explained by an increasing mitochondrial contribution to Ca(2+) sequestration.

Adenosine Triphosphate↗
PubMed1998

The Vestigial and Scalloped proteins act together to directly regulate wing-specific gene expression in Drosophila.

A small number of major regulatory (selector) genes have been identified in animals that control the development of particular organs or complex structures. In Drosophila, the vestigial gene is required for wing formation and is able to induce wing-like outgrowths on other structures. However, the molecular function of the nuclear Vestigial protein, which bears no informative similarities to other proteins, was unknown. Here, we show that Vestigial requires the function of the Scalloped protein, a member of the TEA family of transcriptional regulators, to directly activate the expression of genes involved in wing morphogenesis. Genetic and molecular analyses reveal that Vestigial regulates wing identity by forming a complex with the Scalloped protein that binds sequence specifically to essential sites in wing-specific enhancers. These enhancers also require the direct inputs of signaling pathways, and the response of an enhancer can be switched to another pathway through changes in signal-transducer binding sites. Combinatorial regulation by selector proteins and signal transducers is likely to be a general feature of the tissue-specific control of gene expression during organogenesis.

Animals↗
PubMed1998

Ultrabithorax regulates genes at several levels of the wing-patterning hierarchy to shape the development of the Drosophila haltere.

Arthropods and vertebrates are constructed of many serially homologous structures whose individual patterns are regulated by Hox genes. The Hox-regulated target genes and developmental pathways that determine the morphological differences between any homologous structures are not known. The differentiation of the Drosophila haltere from the wing through the action of the Ultrabithorax (Ubx) gene is a classic example of Hox regulation of serial homology, although no Ubx-regulated genes in the haltere have been identified previously. Here, we show that Ubx represses the expression of the Wingless (Wg) signaling protein and a subset of Wg- and Decapentaplegic-activated genes such as spalt-related, vestigial, Serum Response Factor, and achaete-scute, whose products regulate morphological features that differ between the wing and haltere. In addition, we found that some genes in the same developmental pathway are independently regulated by Ubx. Our results suggest that Ubx, and Hox genes in general, independently and selectively regulate genes that act at many levels of regulatory hierarchies to shape the differential development of serially homologous structures.

Animals↗
PubMed1998

Diurnal variation of adrenocortical activity in chronic fatigue syndrome.

Baseline morning and evening serum cortisol and ACTH concentrations, and diurnal changes in hormone levels, were measured in 30 patients with chronic fatigue syndrome (CFS) but without concurrent depressive disorder and a control group of 15 weight-, age- and sex-matched healthy volunteers. Morning cortisol levels were non-significantly lower in CFS patients, while evening levels were non-significantly higher. ACTH concentrations were non-significantly higher in both the morning and evening. The diurnal change in cortisol levels was significantly less in CFS than in controls (p < 0.05). In CFS subjects, evening levels of cortisol correlated significantly with measures of general health and physical functioning, while diurnal change in cortisol was positively correlated with measures of functional improvement over the past year and current social functioning. These results suggest that there is a relationship between adrenocortical function and disability in CFS, but do not reveal the causal connection.

Adrenal Cortex↗
PubMed1998

Breast cancer. Part 3: Psychosocial care.

Psychosocial care, information-giving and issues surrounding patient choice are important aspects in the nursing care of women with breast cancer. Patients with breast cancer consistently identify communication as an area of central importance. The nurse, specialist or otherwise, has an important role in addressing patients' needs following diagnosis and treatment for breast cancer.

Adaptation, Psychological↗
PubMed1998

Breast cancer. Part 2: Management.

Management of breast cancer will depend on its stage and degree of spread. Management may be by surgery, chemotherapy, endocrine therapy or radiotherapy, or a combination of some or all of these.

Antineoplastic Agents↗
PubMed1997

Fossils, genes and the evolution of animal limbs.

The morphological and functional evolution of appendages has played a crucial role in the adaptive radiation of tetrapods, arthropods and winged insects. The origin and diversification of fins, wings and other structures, long a focus of palaeontology, can now be approached through developmental genetics. Modifications of appendage number and architecture in each phylum are correlated with regulatory changes in specific patterning genes. Although their respective evolutionary histories are unique, vertebrate, insect and other animal appendages are organized by a similar genetic regulatory system that may have been established in a common ancestor.

Adaptation, Physiological↗
PubMed1997

Development of a sensitive method for quantitation of ABT-089 in plasma using fluorescence labeling with 7-fluoro-4-nitrobenzo-2-oxa-1,3-diazole.

A high-performance liquid chromatography method for the quantitation of ABT-089 [2-methyl-3-(2-(S)-pyrrolidinylmethoxy)pyridine] (I), a new structural type of cholinergic channel modulators (ChCM), is described in this paper using 7-fluoro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-F) as a fluorescent-labeling reagent. The method combined an optimized liquid-liquid extraction from plasma followed by pre-column derivatization to yield a fluorescence product. The selectivity, sensitivity, and reproducibility of this method were found to be excellent. This method was applied to the determination of ng/ml plasma and tissue levels of ABT-089 and similar compounds in biological samples.

4-Chloro-7-nitrobenzofurazan↗
PubMed1997

Evolution of the entire arthropod Hox gene set predated the origin and radiation of the onychophoran/arthropod clade.

BACKGROUND: Dramatic changes in body size and pattern occurred during the radiation of many taxa in the Cambrian, and these changes are best documented for the arthropods. The sudden appearance of such diverse body plans raises the fundamental question of when the genes and the developmental control systems that regulate these designs evolved. As Hox genes regulate arthropod body patterns, the evolution of these genes may have played a role in the origin and diversification of the arthropod body plan from a homonomous ancestor. To trace the origin of arthropod Hox genes, we examined their distribution in a myriapod and in the Onychophora, a sister group to the arthropods. RESULTS: Despite the limited segmental diversity within myriapods and Onychophora, all insect Hox genes are present in both taxa, including the trunk Hox genes Ultrabithorax and abdominal-A as well as an ortholog of the fushi tarazu gene. Comparative analysis of Hox gene deployment revealed that the anterior boundary of expression of trunk Hox genes has shifted dramatically along the anteroposterior axis between Onychophora and different arthropod classes. Furthermore, we found that repression of expression of the Hox target gene Distal-less is unique to the insect lineage. CONCLUSIONS: A complete arthropod Hox gene family existed in the ancestor of the onychophoran/arthropod clade. No new Hox genes were therefore required to catalyze the arthropod radiation; instead, arthropod body-plan diversity arose through changes in the regulation of Hox genes and their downstream targets.

Amino Acid Sequence↗