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D Holbert

Publications and source records attributed to D Holbert.

At least 19 recordsLinked to original sources
PubMed2001

Evolution of mitral valve surgery: toward a totally endoscopic approach.

BACKGROUND: Our study evaluates a series of video-assisted minimally invasive mitral operations, showing safe progression toward totally endoscopic techniques. METHODS: Consecutive patients with isolated mitral valve disease underwent either manually directed (n = 55) or voice-activated robotically directed (n = 72) video-assisted mitral operations. Cold blood cardioplegia, a transthoracic aortic clamp, a 5-mm endoscope, and a 5-cm minithoracotomy were used. This video-assisted minimally invasive mitral operation cohort was compared with a previous sternotomy-based mitral operation cohort (n = 100). RESULTS: Group demographics, New York Heart Association classification, and cardiac function were similar. Repairs were performed in 61.8% manually directed (n = 34), 75.0% robotically directed (n = 54), and 54% sternotomy-based (N = 54) mitral operations. The robotically directed technique showed a significant decrease in blood loss, ventilator time, and hospitalization compared with the sternotomy-based technique. Manually directed mitral operations compared with robotically directed mitral operations had decreased arrest times (128.0 +/- 4.5 minutes compared with 90.0 +/- 4.6 minutes; p < 0.001) and decreased perfusion times (173.0 +/- 5.7 minutes compared with 144.0 +/- 4.6 minutes; p < 0.001). In the minimally invasive mitral operation cohort, complications included reexploration for bleeding (2.4%; n = 3) and one stroke (0.8%), whereas the 30-day mortality was 2.3% (n = 3). CONCLUSIONS: Video-assisted mitral surgery provides safe and effective results when compared with conventional sternal approaches. These positive results show a safe and stepwise evolution toward a totally endoscopic mitral valve operation.

Adult↗
PubMed2001

Effects of socioeconomic status on the obesity knowledge of adolescents from six Latin American cities.

OBJECTIVE: To examine the effects of socioeconomic status (SES) on the obesity knowledge of adolescents in six Latin American cities. DESIGN: Data were collected using an anonymous, self-administered questionnaire consisting of demographic questions and a 25-item multiple-choice obesity knowledge test. Test items were clustered under five topics: the fat and calorie content of foods and beverages; weight loss methods; energy expenditure; food preparation methods; and the relationship between obesity and health. SUBJECTS: A total of 1272 ninth grade students from higher and lower SES families were recruited at schools in Buenos Aires, Argentina (n=195); Guatemala City, Guatemala (n=212); Havana, Cuba (n=213); Lima, Peru (n=218); Panama City, Panama (n=195); and Santiago, Chile (n=239). RESULTS: Mean test scores reflected a low level of obesity knowledge among adolescents from higher and lower SES groups in all six cities. Nevertheless, a trend for higher scores emerged in favor of adolescents from wealthier families. This income effect persisted after controlling for gender and weight status. The weakest knowledge areas among youth from the higher SES groups were food preparation methods and the relationship between obesity and health while those for adolescents from the lower SES groups were the fat and calorie content of foods and beverages and the relationship between obesity and health. Classroom instruction about obesity was generally more available to students from the higher SES groups. The majority of adolescents from both SES groups were interested in learning more about weight loss methods, energy expenditure, and the fat and calorie content of foods and beverages. The topic of least interest was the relationship between obesity and health. CONCLUSION: These preliminary findings suggest a need for more obesity education programs for adolescents, especially for those living in poverty.

Adolescent↗
PubMed2000

Electrophysiologic signs of auditory competition in the human brain.

The present project investigated the electrophysiologic effects of auditory competition on components of the late auditory evoked potential (LAEP). A group of 12 young female listeners attended to deviant tones interspersed among frequent tones in one ear while trains of deviant and frequent tones of a different frequency were either present or absent at the opposite ear. Comparison of event-related potential (ERP) waveforms with competition- and attention-related difference waves revealed evidence that the neural effects of competition were not simply a moderation of the effects of selective attention (i.e. the processing negativity). The two difference waves exhibited amplitude peaks that were not mirror-images with respect to polarity. This suggests the existence of a unique underlying neural process that is responsible for the effects of competition on the LAEP.

Acoustic Stimulation↗
PubMed2000

Cytokines and cell adhesion molecules associated with high-intensity eccentric exercise.

Unaccustomed, eccentrically biased exercise induces trauma to muscle and/or connective tissue. Tissue damage activates an acute inflammatory response. Inflammation requires the effective interaction of different physiological and biological systems. Much of this is coordinated by the de novo synthesis of families of protein molecules, cytokines. The purpose of the present paper was to determine changes in blood levels of various cytokines in response to exercise-induced muscle damage that was effected using high-intensity eccentric exercise. Six healthy, untrained, college-age male subjects were required to perform the eccentric phase of a bench press and a leg curl (4 sets, 12 repetitions/set) at an intensity equivalent to 100% of their previously determined one-repetition maximum. Samples of blood were drawn at the following times: before exercise and 1.5, 6, 12, 24, 48, 72, 96, 120, and 144 h after exercise. These samples were analyzed for interleukins (IL): IL-1beta, IL-6, and IL-10; tumor necrosis factor-alpha; colony stimulating factors (CSF): granulocyte-CSF, macrophage-CSF, and GM-CSF; for cell adhesion molecules (CAM): P- and E-selectin, and intercellular cell adhesion molecule (ICAM-1), and vascular cell adhesion molecule (VCAM-1). Results were analyzed using a repeated-measures analysis of variance (P = 0.05). Compared to baseline values, IL-1beta was reduced (P = 0.03) at 6, 24, and 96-144 h after exercise; IL-6 was elevated (P = 0.01) at 12, 24, and 72 h after exercise; IL-10 was elevated (P = 0.009) between 72 and 144 h after exercise; M-CSF was elevated (P = 0.005) at 12 and 48-144 h after exercise; and P-selectin was reduced (P = 0.01) between 24 and 144 h after exercise. It is concluded that when high-intensity eccentric exercise is compared to strenuous endurance exercise, post-exercise changes in cytokines do occur, but they are generally of a smaller magnitude, and occur at a later time period after the termination of exercise.

Adult↗
PubMed2000

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Journal Article↗
PubMed2000

Mucosal IL-12 is more effective than systemic IL-12 in augmenting IFN-gamma expression and inhibiting allergic lung eosinophilia in murine lungs.

The relative efficacy of mucosal (intratracheal) and systemic (intraperitoneal) delivery of interleukin (IL)-12 was evaluated in a mouse model of allergic lung eosinophilia. Mucosal administration of IL-12 achieved 100- to 600-fold higher bronchoalveolar lavage (BAL) levels of IL-12, but 2- to 10-fold lower serum levels compared to systemic administration. Whereas both mucosal and systemic IL-12 inhibited BAL eosinophil recruitment at high doses (100-1000 ng), only mucosal IL-12 was effective at low doses (1-10 ng). Mucosal, but not systemic, administration of 1000 ng of IL-12 increased interferon (IFN)-gamma expression in BAL cells. In a model of ongoing eosinophilic inflammation, when mucosal or systemic IL-12 doses were initiated prior to peak eosinophilia, further eosinophil recruitment was inhibited. However, when IL-12 treatment was initiated after peak eosinophil recruitment occurred, recovery from eosinophilic inflammation was not facilitated. Our findings are the first to demonstrate that locally administered IL-12 inhibits eosinophil recruitment at 100-fold lower doses than systemic IL-12. The most likely mechanism of this enhanced inhibitory activity is a sustained increase in lung levels of IL-12 that augments IFN-gamma production from BAL cells. We suggest that future studies should evaluate the efficacy of low doses of nebulized IL-12 in inhibiting eosinophilic lung inflammation in asthma.

Adjuvants, Immunologic↗
PubMed2000

Mucosal IL-12 inhibits airway reactivity to methacholine and respiratory failure in murine asthma.

The worldwide incidence, prevalence, and fatality rates from asthma are increasing despite currently available therapeutic modalities. Systemic administration of interleukin (IL)-12 has been shown to inhibit airway reactivity in murine models of asthma, but the required dosage is high and may be toxic. This study tested the hypothesis that IL-12 administered directly into the lungs is more effective in inhibiting airway reactivity than systemically administered IL-12, allowing lower doses to be used. A low dose (10 ng) of IL-12 was delivered either intratracheally (mucosal delivery) or intraperitoneally (systemic delivery) at the time of ragweed (RW) challenge in mice sensitized to RW. Basal airway resistance and airway reactivity to methacholine were measured 3 days after RW challenge. Compared to phosphate-buffered saline (PBS) challenge of RW sensitized mice, RW challenge increased basal resistance and the slope of the methacholine dose-response curve. Methacholine challenge of RW-challenged mice also induced premature respiratory failure (respiratory rate < 150/min, tidal volume < 0.15 mL) in some animals. Administration of mucosal or systemic IL-12 at the time of RW challenge decreased basal airway resistance. However, only mucosal IL-12 decreased airway reactivity and inhibited respiratory failure during methacholine challenge. These findings indicate that mucosal delivery of a low dose of IL-12 is more effective than systemic IL-12 in inhibiting airway reactivity and respiratory failure in a mouse model of asthma.

Adjuvants, Immunologic↗
PubMed1999

A single very early dexamethasone dose improves respiratory and cardiovascular adaptation in preterm infants.

OBJECTIVES: To test the hypothesis that a single dose of dexamethasone given soon after delivery to infants <28 weeks' gestation leads to improved cardiopulmonary adaptation in the first week and lowers the risk of significant intraventricular hemorrhage. METHODS: In a prospective, blinded, placebo-controlled study, we randomly assigned 70 infants <28 weeks' gestation who were born in the hospital to receive dexamethasone (0.2 mg/kg) (n = 37) or normal saline solution (n = 33) within 2 hours of delivery. After an interim analysis showed that the incidence of intraventricular hemorrhage was much lower than expected, enrollment was stopped and we limited our analysis to a comparison of ventilator settings, blood pressure, and pressor use during the first 7 days. RESULTS: Clinical characteristics of the groups were comparable at study entry. Ventilator weaning occurred more rapidly in the patients who received dexamethasone: their intermittent mandatory ventilation rate was significantly lower on days 1 through 6, and their peak inspiratory pressure was lower on days 3 through 7 compared with the control group. Mean blood pressures were higher in the dexamethasone group within 12 hours and remained higher through day 5, but the use of pressors was not different. Fewer infants in the dexamethasone group received indomethacin to treat a patent ductus arteriosus (22% vs 47%, P <.03). CONCLUSION: Dexamethasone given within 2 hours of delivery to preterm infants <28 weeks' gestation resulted in lower ventilator settings and higher mean blood pressures during the first 7 days. Fewer infants required indomethacin to treat a patent ductus arteriosus.

Adaptation, Physiological↗
PubMed1998

Differential white cell count after two bouts of downhill running.

The purpose of this study was to compare blood markers associated with eccentrically biased exercise and muscle damage, after two bouts of downhill running. Nine active, untrained males performed 2 x 45 min bouts of downhill running (-0.16 radians), at a speed that would elicit 70% of each subjects VO2max, on a level grade; runs were spaced 14d apart (RUN1, RUN2). Blood samples were obtained before, after, and every hour for 12 h after exercise, as well as every 24 h for 5 d, to assess numbers of circulating neutrophils, monocytes, and lymphocytes, serum cortisol, creatine kinase (CK); subjective sensations of delayed onset muscle soreness (DOMS) were monitored. To control for diurnal variation, two weeks prior to the RUN1, subjects had blood draws performed at the same time as would occur after exercise, but did no exercise (CONTROL). During the 5 d after exercise, DOMS and CK were significantly greater (p < 0.05) after RUN1 compared to RUN2 and CONTROL. During the 12 h after RUN1 and RUN2, neutrophils showed similar responses compared to CONTROL. However, neutrophils were significantly elevated at 96 h after RUN1 and 24 h after RUN2. Monocytes were significantly elevated during 5-11 h after RUN1 and RUN2, compared to CONTROL. Cortisol showed a similar significant diurnal decrease for all three conditions during the 12 h following exercise. The significantly lower levels of CK and DOMS seen after RUN2, compared with the initial run is consistent with the literature. The similar changes in neutrophils and monocytes during the 12 h following RUN1 and RUN2, followed by disparate responses over the subsequent 5 d, requires further investigation.

Adult↗
PubMed1996

Immunomodulatory effects of IL-12 on allergic lung inflammation depend on timing of doses.

We investigated the effects of IL-12 on a murine model of allergic lung inflammation. Administration of IL-12 was timed to interfere with either allergic sensitization (early dosage) or the hypersensitivity inflammatory response in the lung (late dosage), or both (early and late dosages). Comparisons of IL-12- and PBS-treated animals within each treatment group revealed several noticeable effects of IL-12. Early dosage, and the combination of early and late dosages, strikingly decreased ragweed-specific serum IgE, tracheal ring reactivity to acetylcholine, and BAL eosinophilia following allergen challenge. In contrast, late dosage had no effect on IgE levels and only a minimal effect on tracheal ring reactivity, but had a modest effect on recruitment of eosinophils. Early dosage down-regulated IL-5 and IL-10, but did not alter IL-4 or IFN-gamma expression. Late dosage down-regulated IL-5, up-regulated IL-10 and IFN-gamma, but did not change IL-4 expression. The combination of early and late dosage down-regulated IL-4, IL-5, and IL-10 expression, but increased IFN-gamma expression and production in the BAL cells and fluids. Taken together, these results indicate that IL-12 has potent immunomodulatory effects on allergic lung inflammation that depend on the timing of IL-12 administration relative to allergic sensitization and allergen challenge.

Acetylcholine↗
PubMed1996

A double-blind crossover study in moderately hypercholesterolemic men that compared the effect of aged garlic extract and placebo administration on blood lipids.

A double-blind crossover study comparing the effect of aged garlic extract with a placebo on blood lipids was performed in a group of 41 moderately hypercholesterolemic men [cholesterol concentrations 5.7-7.5 mmol/L (220-290 mg/dL)]. After a 4-wk baseline period, during which the subjects were advised to adhere to a National Cholesterol Education Program Step I diet, they were started on 7.2 g aged garlic extract per day or an equivalent amount of placebo as a dietary supplement for a period of 6 mo, then switched to the other supplement for an additional 4 mo. Blood lipids, blood counts, thyroid and liver function measures, body weight, and blood pressure were followed over the entire study period. The major findings were a maximal reduction in total serum cholesterol of 6.1% or 7.0% in comparison with the average concentration during the placebo administration or baseline evaluation period, respectively. Low-density-lipoprotein cholesterol was also decreased by aged garlic extract, 4% when compared with average baseline values and 4.6% in comparison with placebo period concentrations. In addition, there was a 5.5% decrease in systolic blood pressure and a modest reduction of diastolic blood pressure in response to aged garlic extract. We conclude that dietary supplementation with aged garlic extract has beneficial effects on the lipid profile and blood pressure of moderately hypercholesterolemic subjects.

Adult↗
PubMed1994

The impact of a repeated bout of eccentric exercise on muscular strength, muscle soreness and creatine kinase.

The purpose of this study was to determine if there were any beneficial or detrimental effects regarding delayed onset muscle soreness (DOMS), serum creatine kinase (CK), and maximum concentric strength at 80% of 1-RMconc, if a bout of eccentric exercise was repeated at 48 h after an initial bout. A secondary purpose was to determine whether unaccustomed eccentrics might affect plasma cholesterol (TC). Twenty-six men were randomly assigned to a control (Group 1) or experimental group (Group 2). Both groups performed three sets (12 repetitions per set) of the eccentric phase of a chest press, at 80% of one repetition maximum (1-RMconc); Group 2 repeated this exercise 48 h later. DOMS and CK were measured before, and every 24 h for 8 days after; TC was measured before, and every 24 h for 4 days. Maximum strength during the concentric phase of a chest press (1-RMconc) was measured before and at 48-h intervals after. A repeated measures analysis of variance revealed a significant time effect (P < 0.05) for DOMS, CK and strength, but no significant difference between groups (P < 0.05). An interesting finding was the significant (P < 0.05) reduction in TC at 24, 48 and 72 h, after exercise in both groups, which we hypothesized was associated with cellular repair. From these results we concluded that when a bout of eccentrics is repeated 48 h after an initial bout, there is no change in the characteristic time-course and/or intensity of DOMS, CK or 1-RMconc.

Adult↗
PubMed1994

The effects of athletic massage on delayed onset muscle soreness, creatine kinase, and neutrophil count: a preliminary report.

It was hypothesized that athletic massage administered 2 hours after eccentric exercise would disrupt an initial crucial event in acute inflammation, the accumulation of neutrophils. This would result in a diminished inflammatory response and a concomitant reduction in delayed onset muscle soreness (DOMS) and serum creatine kinase (CK). Untrained males were randomly assigned to a massage (N = 7) or control (N = 7) group. All performed five sets of isokinetic eccentric exercise of the elbow flexors and extensors. Two hours after exercise, massage subjects received a 30-minute athletic massage; control subjects rested. Delayed onset muscle soreness and CK were assessed before exercise and at 8, 24, 48, 72, 96, and 120 hours after exercise. Circulating neutrophils were assessed before and immediately after exercise, and at 30-minute intervals for 8 hours; cortisol was assessed before and immediately after exercise, and at 30-minute intervals for 8 hours; cortisol was assessed at similar times. A trend analysis revealed a significant (p < 0.05) treatment by time interaction effect for 1) DOMS, with the massage group reporting reduced levels; 2) CK, with the massage group displaying reduced levels; 3) neutrophils, with the massage group displaying a prolonged elevation; and 4) cortisol, with the massage group showing a diminished diurnal reduction. The results of this study suggest that sports massage will reduce DOMS and CK when administered 2 hours after the termination of eccentric exercise. This may be due to a reduced emigration of neutrophils and/or higher levels of serum cortisol.

Adult↗
PubMed1991

Effects of fitness level and the regional distribution of fat on carbohydrate metabolism and plasma lipids in middle- to older-aged men.

Many cross-sectional studies have demonstrated the influences of fitness level or the regional distribution of fat on lipid and carbohydrate metabolism; however, the relative contribution of these two variables in the same subjects has not been extensively examined. The purpose of this study was to determine the impact of regional adiposity on plasma lipids and carbohydrate metabolism in middle- to older-aged men with a wide range of fitness levels. Forty-six sedentary and exercise-trained men (age [mean +/- SE], 52.8 +/- 0.88 years) were included in this study. Fitness level was assessed by (a) time to exhaustion, and (2) maximal oxygen uptake achieved during an incremental treadmill test. Plasma lipid levels were determined in the basal, fasting state. Carbohydrate metabolism was evaluated by the glucose and insulin responses (total glucose and insulin areas under the curve, insulin sensitivity index [ISI]) to a 75-g, 2-hour oral glucose tolerance test (OGTT). Abdomen to hip ratio (AHR) was used as the index of regional adiposity. Multiple regression analysis indicated that fitness level and the percentage of body fat were significant predictors (approximately 56% of total variance) for total insulin area under the curve and the ISI. A comparison between the sedentary and trained subjects showed that training resulted in an improved ISI at an equal AHR. Fitness level was also the only significant multiple regression predictor for high-density lipoprotein (HDL)-cholesterol (25% of total variance) and accounted for the greatest amount of variance in triglyceride levels (34%), although AHR was also a significant predictor (6%).(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed1991

An evaluation of waist to hip ratio measurement methods in relation to lipid and carbohydrate metabolism in men.

The purpose of this study was to determine which method of measuring waist to hip ratio (WHR) was the most effective in assessing decrements associated with an abdominal fat distribution in 46 non-obese, middle to older aged men (mean +/- s.e., age 52.8 +/- 0.88 years; body fat 19.7 +/- 0.72 percent). Circumferences were obtained at the following sites and WHR calculated (waist circumference/hip circumference): (1) minimal waist/maximal hip; (2) level of umbilicus/maximal hip; (3) level of umbilicus/level of greater trochanters; (4) level of umbilicus/level of superior iliac spine; and (5) level of 1/3 of the distance between the xiphiod process and umbilicus/level 4 cm below the superior iliac spine. Significant (P less than 0.05) associations were observed for measurement methods 1, 2 and 3 with indices of lipid and carbohydrate metabolism, body composition, and fitness level. Measurement method 5 was not related to any metabolic or physiological variables, while measurement method 4 was intermediate in terms of the strength of the associations. These findings suggest that the predictive strength of WHR can vary depending upon the measurement method used.

Anthropometry↗
PubMed1990

Trend analysis for repeated measures designs.

This paper outlines a method of analysis that is well-suited to repeated measures designs. This method uses polynomial functions of time to characterize an outcome variable measured at several distinct time points on the same subjects. Profiles for different treatment groups may be compared using the appropriate interaction terms in an analysis of variance table. The method is illustrated with data from two recent studies.

Absenteeism↗
PubMed1988

Personality profiles associated with smokeless tobacco use patterns.

The purpose of this study was to examine the personality characteristics of male dippers and chewers of smokeless tobacco. The study objective was to determine any differences in personality characteristics between dippers and chewers of smokeless tobacco and nonusers. A survey at a southeastern university provided a sample of 289 males, of which 55 (19%) were smokeless tobacco users. Each subject was administered a demographic data sheet and Cattell's Sixteen Personality Factor Questionnaire (16 PF). Smokeless tobacco users were categorized as snuff dippers or tobacco chewers, and comparisons of personality characteristics were made between persons who exclusively dipped, persons who exclusively chewed, persons who dipped and chewed, and persons who did neither. The results of the study indicated that smokeless tobacco use is primarily a White male habit; very few Blacks or other racial groups consumed smokeless tobacco among this population. Significant (p less than 0.05) personality differences between snuff dippers and tobacco chewers were noted. Snuff dippers were more socially outgoing, enthusiastic, imaginative and group dependent than chewers. Chewers were found to be more uncompromising, critical in outlook and practical and less easily influenced by others than dippers.

Adolescent↗