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Biomedical subjects

T Ashikaga

Publications and source records attributed to T Ashikaga.

At least 37 records · Page 2Linked to original sources
PubMed2000

Helping women quit smoking: results of a community intervention program.

OBJECTIVES: This intervention was implemented to reduce the prevalence of cigarette smoking among women. METHODS: We used community organization approaches to create coalitions and task forces to develop and implement a multicomponent intervention in 2 counties in Vermont and New Hampshire, with a special focus on providing support to help women quit smoking. Evaluation was by pre-intervention and post-intervention random-digit-dialed telephone surveys in the intervention counties and the 2 matched comparison counties. RESULTS: In the intervention counties, compared with the comparison counties, the odds of a woman being a smoker after 4 years of program activities were 0.88 (95% confidence interval = 0.78, 1.00) (P = .02, 1-tailed); women smokers' perceptions of community norms about women smoking were significantly more negative (P = .002, 1-tailed); and the quit rate in the past 5 years was significantly greater (25.4% vs 21.4%; P = .02, 1-tailed). Quit rates were significantly higher in the intervention counties among younger women (aged 18 to 44 years); among women with household annual incomes of $25,000 or less; and among heavier smokers (those who smoked 25 or more cigarettes daily). CONCLUSIONS: In these rural counties, community participation in planning and implementing interventions was accompanied by favorable changes in women's smoking behavior.

Adolescent↗
PubMed2000

Effects of ultrasound and stretch on knee ligament extensibility.

STUDY DESIGN: Randomized, double-blind pre-test and post-test with repeated measures. OBJECTIVE: To determine whether heating with continuous wattage ultrasound (CWUS) augmented the effects of stretching on ligament extensibility in nonimpaired human subjects. BACKGROUND: Heating with CWUS, combined with static stretching, is often used to treat ligament "tightness," but "heat and stretch" has not been studied well in vivo. METHODS AND MEASURES: Twenty-one nonimpaired women subjects (aged 31.5 +/- 11.0 years) underwent serial measurements of knee joint displacement (valgus and varus) on a Genucom arthrometer before and after valgus stretch (10 ft-lb x 2.5 minutes). Subjects received either simultaneous CWUS (3 MHz, 1.25 W/cm2) or sham CWUS applied over the medial collateral ligament. Five trials (2 before, 3 after treatment) were conducted with the right knee positioned in 20 degrees of flexion. Subjects received the alternate treatment 28 days later. For each subject, all testing was performed by the same investigator. RESULTS: Repeated measures ANOVA revealed that stretching, combined with sham CWUS, increased mean valgus displacement from 8.95 degrees (+/-1.72 degrees) to 10.00 degrees (+/-2.10 degrees). Stretching, combined with CWUS, increased mean valgus displacement from 9.24 degrees (+/-2.36 degrees) to 10.48 degrees (+/-2.54 degrees). This was a 13.4% change from the control condition. CONCLUSION: Heating with CWUS did not augment the effects of stretching. "Heat and stretch" with CWUS may not be more effective than stretching alone for increasing the extensibility of dense connective tissue.

Adolescent↗
PubMed1999

Effect of dipyridamole on QT dispersion in vasospastic angina pectoris.

Life-threatening ventricular arrhythmias have frequently been documented in patients with vasospastic angina. Moreover, the incidence of ventricular arrhythmias has been closely associated with increased QT dispersion. However, the underlying mechanism responsible for this arrhythmogenesis has not been clarified. The effects of dipyridamole and subsequent aminophylline administration on QT dispersion were examined in 35 patients with vasospastic angina and 30 patients with atypical chest pain. None of the patients enrolled in this study revealed any significant stenosis in coronary angiography. QT dispersion during dipyridamole followed by aminophylline administration was compared between the 2 groups. The baseline QT dispersion was similar in both groups (vasospastic angina: 27 +/- 8 ms; atypical chest pain: 28 +/- 7 ms). No significant changes in QT dispersion were observed in patients with atypical chest pain by dipyridamole (23 +/- 9 ms) and subsequent aminophylline administration (23 +/- 5 ms). However, the QT dispersion in patients with vasospastic angina increased significantly by dipyridamole administration (53 +/- 14 ms, p <0.0001) and returned to baseline by subsequent aminophylline administration (26 +/- 10 ms). Our data suggest that the disparity of ventricular repolarization in vasospastic angina may be mediated by increased endogenous adenosine.

Adult↗
PubMed1999

Effect of short-term hormone replacement therapy on left ventricular mass and contractile function.

OBJECTIVE: To determine the effect of hormone replacement therapy (HRT) on cardiac structure and function and whether these changes are related to changes in blood volume. DESIGN: Open-label pilot study. SETTING: Academic medical center. PATIENT(S): Eighteen healthy postmenopausal women. INTERVENTION(S): We administered medroxyprogesterone acetate orally, 5 mg/d for 2 months followed by 2 months of oral sequential 17beta-estradiol, 1 mg/d plus medroxyprogesterone acetate, 10 mg/d for the last 12 days of each month. MAIN OUTCOME MEASURE(S): Cardiac output, stroke volume, heart rate, end diastolic volume, end systolic volume, ejection fraction, and left ventricular mass were measured by echocardiography; blood and plasma volumes were measured using 125I-albumin dilution. RESULT(S): Cardiac output, stroke volume, left ventricular mass, end diastolic volume, and ejection fraction increased by 12.8%, 11.7%, 9.4%, 7.2%, and 10.9%, respectively, by 16 weeks. End systolic volume decreased, whereas heart rate was unaffected. There was a significant increase in blood volume (5.2%) and plasma volume (4.8%) from baseline during treatment, which could explain the increased cardiac output but not the increased ejection fraction. CONCLUSION(S): Hormone replacement therapy causes modest but significant increases in cardiac output, ejection fraction, and left ventricular mass. These pilot data suggest a direct myocardial effect of HRT that is preload independent.

Blood Volume↗
PubMed1999

Effect of short-term medroxyprogesterone acetate on left ventricular mass: role of insulin-like growth factor-1.

Previous studies using 17beta-estradiol and medroxyprogesterone acetate (MPA) have shown that hormone replacement therapy (HRT) increases left ventricular mass (LVM). To determine if insulin-like growth factor-1 (IGF-1) is associated with the increase in LVM, we measured IGF-1 and IGF-binding protein-3 (IGFBP-3) levels in 19 postmenopausal women before and after 8 weeks of oral treatment with MPA 5 mg/d. LVM was measured by two-dimensional echocardiography. Changes in IGF-1, IGFBP-3, and LVM from baseline were analyzed by paired ttest. Regression analysis was used to determine if changes in the IGF-1 axis with MPA treatment affect the increase in LVM. LVM increased 4.4% during the study (P = .006 vbaseline). IGF-1 increased 17% with MPA (P = .008), whereas IGFBP-3 did not change. The IGF-1/IGFBP-3 ratio increased 16.8% (P = .0003). Regression analysis of LVM with IGF-1, IGFBP-3, and the IGF-1/IGFBP-3 ratio suggested that IGF-1 during MPA therapy explains 2.4% and the IGF-1/IGFBP-3 ratio explains 3.2% of the variation in LVM. There was no effect of IGFBP-3 on LVM. Most of the variation in LVM with MPA (90.5%) was explained by baseline LVM. The IGF-1/IGFBP-3 ratio on MPA treatment was inversely related to the change in LVM: women with a lower LVM at baseline had the greatest increase in LVM with MPA. These findings suggest that MPA increases IGF-1 and LVM. Because the increase in IGF-1 with MPA treatment explains a fraction of the increase in LVM, other mechanisms must also be operative.

Echocardiography↗
PubMed1999

Quantitative polymerase chain reaction using an external control mRNA for determination of gene expression in a heterogeneous cell population.

Gene expression can be evaluated quantitatively by conventional RT-PCR or Northern blotting with the aid of a correction based on the expression of an internal control gene. However, this approach is not suitable for quantitating gene expression in a group of heterogeneous cell subsets, because the internal control gene expression may vary among the subsets. Therefore, we developed a new method for quantitative PCR using rat poly(A)+ RNA as an external control. We used this method to investigate cytokine gene expression in lymph node cells from mice during the induction of contact hypersensitivity. Expression of the murine glyceraldehydephosphate dehydrogenase (GAPDH) gene, a candidate internal control, was not constant in cells from trinitrochlorobenzene- and vehicle-applied animals, suggesting that GAPDH gene expression changes in heterogeneous lymph node-cell subsets during induction of contact hypersensitivity. Therefore, we decided to use rat GAPDH mRNA as an external control. Cytokine gene expression was measured by quantitative PCR and was corrected based on external rat GAPDH cDNA. The reliability of this quantitative PCR was superior to that of the conventional method with an internal control.

Animals↗
PubMed1998

The sentinel node in breast cancer--a multicenter validation study.

BACKGROUND: Pilot studies indicate that probe-guided resection of radioactive sentinel nodes (the first nodes that receive drainage from tumors) can identify regional metastases in patients with breast cancer. To confirm this finding, we conducted a multicenter study of the method as used by 11 surgeons in a variety of practice settings. METHODS: We enrolled 443 patients with breast cancer. The technique involved the injection of 4 ml of technetium-99m sulfur colloid (1 mCi [37 MBq]) into the breast around the tumor or biopsy cavity. "Hot spots" representing underlying sentinel nodes were identified with a gamma probe. Sentinel nodes subjacent to hot spots were removed. All patients underwent a complete axillary lymphadenectomy. RESULTS: The overall rate of identification of hot spots was 93 percent (in 413 of 443 patients). The pathological status of the sentinel nodes was compared with that of the remaining axillary nodes. The accuracy of the sentinel nodes with respect to the positive or negative status of the axillary nodes was 97 percent (392 of 405); the specificity of the method was 100 percent, the positive predictive value was 100 percent, the negative predictive value was 96 percent (291 of 304), and the sensitivity was 89 percent (101 of 114). The sentinel nodes were outside the axilla in 8 percent of cases and outside of level 1 nodes in 11 percent of cases. Three percent of positive sentinel nodes were in nonaxillary locations. CONCLUSIONS: Biopsy of sentinel nodes can predict the presence or absence of axillary-node metastases in patients with breast cancer. However, the procedure can be technically challenging, and the success rate varies according to the surgeon and the characteristics of the patient.

Axilla↗
PubMed1998

Increased QT dispersion in patients with vasospastic angina.

BACKGROUND: The risk factors for ventricular arrhythmias in patients with coronary vasospasm have not been identified. We evaluated QT dispersion in patients with vasospastic angina and its relation to susceptibility to ventricular arrhythmias during myocardial ischemia and reperfusion. METHODS AND RESULTS: We assessed the corrected QT (QTc) dispersion before induction of coronary artery spasm by intracoronary injection of acetylcholine (baseline) and 30 minutes after administration of isosorbide dinitrate in 50 patients with vasospastic angina and 50 patients with atypical chest pain. The baseline QTc dispersion was significantly greater in patients with vasospastic angina than in patients with atypical chest pain (mean+/-SD: 69+/-24 versus 44+/-19 ms, 95% confidence interval of mean difference [CI]: 16 to 33 ms; P<0.001). QTc dispersion decreased significantly, to 48+/-15 ms (CI: 15 to 26 ms; P<0.001 versus baseline), after administration of isosorbide dinitrate in patients with vasospastic angina but did not change significantly in patients with atypical chest pain (mean+/-SD: 41+/-17 ms, CI: -3 to 9 ms). During the provocation test, 24 of 50 patients with vasospastic angina experienced ventricular arrhythmias. The baseline QTc dispersion was significantly greater in patients with than without ventricular arrhythmias (mean+/-SD: 77+/-23 versus 61+/-19 ms, CI: 4 to 26 ms; P<0.05). CONCLUSIONS: Patients with vasospastic angina exhibited an increased baseline QTc dispersion compared with patients with atypical chest pain, which suggests that inhomogeneity of repolarization and susceptibility to ventricular arrhythmias are increased in patients with vasospastic angina, even when asymptomatic. The association between increased QTc dispersion and ventricular arrhythmias during the provocation test suggests that measurement of QT dispersion may help predict which patients with vasospastic angina are at high risk for ventricular arrhythmias during ischemia.

Acetylcholine↗
PubMed1998

Selective induction of interleukin-1 production and tumor killing activity of macrophages through apoptosis by the inhibition of oxidative respiration.

Suppression of mitochondrial respiration and increased glycolysis are characteristic features of activated macrophages. We show here that antimycin A, a respiratory inhibitor, induced interleukin-1 synthesis and tumoricidal activity without inducing tumor necrosis factor or nitric oxide. The induction of tumoricidal activity was resistant to inhibitors of tyrosine-specific protein kinases and intracellular glycoprotein transport. The cognate interaction between macrophages and target cells was not a prerequisite for the tumoricidal activity. In contrast, lipopolysaccharide induced the production of interleukin-1, tumor necrosis factor and nitric oxide, the induction of tumoricidal activity being sensitive to genistein and brefeldin A. Antimycin A, like lipopolysaccharide, induced the release of a cytoplasmic enzyme and apoptosis of macrophages. Antimycin A showed anti-metastatic activity in vivo. These results suggest that the inhibition of oxidative respiration would induce apoptosis and the resultant release of soluble effector molecules of macrophages which inhibit tumor metastasis in vivo.

Animals↗
PubMed1998

Adrenocorticotropic hormone-secreting pheochromocytoma.

A 41-year-old female had pheochromocytoma which secreted adrenocorticotropic hormone (ACTH). She was admitted to our hospital because of weight loss and excessive sweating. Not only urinary metanephrine but also plasma ACTH was extremely high. An abdominal echogram showed a cystic tumor in the left adrenal gland. An abdominal magnetic resonance imaging scan showed a hyperintense T2-weighted abnormality inside the tumor. Left adrenalectomy was done. The tumor consisted of benign pheochromocytoma cells diffusely stained with anti-ACTH antibody. The present case did not show any typical Cushingoid symptoms which are common in ACTH-secreting pheochromocytomas.

Adrenal Gland Neoplasms↗
PubMed1997

Altered expression of cyclic nucleotide phosphodiesterase isozymes during culture of aortic endothelial cells.

Primary cultures of bovine aortic endothelial cells (BAEC) express cyclic nucleotide phosphodiesterase (CN PDE) isozymes of the PDE2, PDE4 and PDE5 gene families. We report here that the isozyme profiles of CN PDE and the amounts of each vary with the passage number of BAEC cultures. Characterization by anion-exchange chromatography and pharmacological criteria were used to study CN PDE in early (4-6), intermediate (6-10), and late (> 17) passages of purified BAEC. PDE2 and a minor fraction of PDE5 accounted for cyclic GMP hydrolysis in early passages, but both isozymes were lost with cell passage. Cyclic AMP was hydrolyzed by both PDE2 and PDE4 isozymes in early passage endothelial cells, but PDE4 was increased dramatically in higher passage cells. Also appearing in the higher passage cells were prominent PDE1 and minor PDE3 activities. The ratios of cytosolic to particulate activities were similar at all passages. BAEC PDE isoforms in intact cells assessed by [3H]-adenine prelabeling showed that atriopeptin II decreased isoproterenol-induced cyclic AMP accumulation in early but not later passage cells, consistent with the loss of PDE2 expression. Enhancement of isoproterenol-induced cyclic AMP accumulation by rolipram, a PDE4 inhibitor, was also greatly diminished during culture passages. Changes in CN PDE isoform expression and consequent cyclic AMP turnover validate the importance of considering cell passage number when cultures of BAEC are used to study the regulation of endothelial cell cyclic nucleotide metabolism and processes mediated by cyclic nucleotides in this model system.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1997

Demonstration of Purkinje potential during idiopathic left ventricular tachycardia: a marker for ablation site by transient entrainment.

During VT of QRS morphology with right bundle branch block and left axis deviation in a patient without obvious structural heart disease, entrainment by pacing from the right ventricular outflow tract and high right atrium was demonstrated. During entrainment of VT, a Purkinje potential preceding the QRS and recorded at the left ventricular mid-septum was activated by orthodromic impulses in the reentry circuit. The interval between the Purkinje potential and the earliest left ventricular activation was decrementally prolonged with shortening of pacing cycle length. Radiofrequency energy was applied to this site, resulting in successful elimination of VT. Therefore, the Purkinje potential represented activation by an orthodromic wavefront in the reentry circuit, while the orthodromically distal site to this potential showed an area of slow conduction with decremental property.

Adult↗
PubMed1997

The effects of heating with ultrasound on knee joint displacement.

UNLABELLED: Heating with continuous wattage ultrasound combined with mobilization procedures is often used to treat ligament "tightness," but the effects of heat on ligament extensibility have not previously been studied in vivo. To address this problem, 25 young adults underwent knee joint displacement tests on a Genucom arthrometer before and after continuous wattage ultrasound (1 MHZ, 1.5 W/cm2 x 8 min). Preultrasound intrarater reliability (ICC; N = 11) was 0.87-0.98 for varus/valgus and recurvatum tests and 0.70-0.73 for anterior-posterior drawer tests. RESULTS: Continuous wattage ultrasound was associated with small increases in mean varus/valgus excursion at 0 degree and 20 degrees of knee flexion (p < or = .04) and in recurvatum excursion (p < or = .04) but not in anterior-posterior drawer excursion. The magnitude of the changes was 1.3 degrees or less and represented relative changes of 6.1-9.8%. CONCLUSION: Continuous wattage ultrasound at common clinical intensities made some knee ligaments slightly more extensible in normal subjects, although the magnitude of the effect was not deemed clinically significant.

Adult↗
PubMed1996

Weight training improves walking endurance in healthy elderly persons.

OBJECTIVE: To determine the effect of a resistance-training program on walking endurance in a healthy, community-dwelling elderly population. DESIGN: 12- week randomized, controlled trial comparing a resistance- training group with a nonexercising control group. SETTING: Hospital-affiliated outpatient exercise facility. PATIENTS: 24 healthy men and women who were 65 years of age or older (mean age +/-SD, 70.4 +/- 4 years; range, 65 to 79 years). MEASUREMENTS: The primary outcome variable was exhaustive submaximal walking time measured at an intensity of 80% of baseline peak aerobic capacity. RESULTS: Participants in the resistance-training program increased submaximal walking endurance by 9 minutes (from 25 +/- 4 minutes to 34 +/- 9 minutes; P=0.001), a 38% increase, whereas no change was seen in controls (20 +/- 5 minutes to 19 +/- 10 minutes; P greater than 0.2; P=0.005 between groups). The relation between change in leg strength and change in walking endurance was significant (r=0.48; P=0.02). Neither group showed a change in peak aerobic capacity or in whole-body composition, although fat-free mass of the leg increased in the exercise group. CONCLUSIONS: Resistance training for 3 months improves both leg strength and walking endurance in healthy, community-dwelling elderly persons. This finding is relevant to older persons at risk for disability, because walking endurance and leg strength are important components of physical functioning.

Aged↗