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Cross Sectional Area (cross + sectional_area)

Distribution by Scientific Domains

Medical Sciences	87%

Selected Abstracts

A quantitative study of the optic nerve in diabetic mutant, Otsuka Long-Evans Tokushima Fatty (OLETF) rats

CONGENITAL ANOMALIES, Issue 4 2001
Kazuhiko Sawada
ABSTRACT, Optic nerves of the Otsuka Long-Evans Tokushima Fatty (OLETF) rat, an animal model of non-insulin dependent diabetes mellitus, were examined using quantitative stereological procedures. At 67 weeks of age, OLETF rats showed a mild hyperglycemia: their blood glucose level was 196 ± 93 mg/dl, significantly higher than that of non-diabetic control Long-Evans Tokushima Otsuka (LETO) rats (110 ± 24 mg/dl). However, there were no differences in the cross sectional area of optic nerves (the mean minimum diameter), the total number and mean diameter of both myelinated and non-myelinated fibers, or the thickness of the myelin sheath between OLETF and LETO rats. The results suggested that a mild hyperglycemia in OLETF rats could not cause any morphological changes in the optic nerve. [source]

In Vitro Validation of a New Approach for Quantitating Regurgitations Using Proximal Isovelocity Surface Area

ECHOCARDIOGRAPHY, Issue 7 2000
A. Delouche
The present work has been designed to validate the calculation of the effective regurgitant orifice (ERO) area with the use of a new formula that takes into account the velocity profile (Vr vs r) and that is insensitive to errors in the determination of the position of the orifice. Assuming a hemispheric model, ERO = 2,r2· Vr/Vo (with Vo= velocity at the orifice) and (Vo/Vr)0.5= (2,/ERO)0.5r. Thus, the slope of the corresponding linear regression allows ERO to be calculated as: ERO = 2,/slope2. This approach was tested in vitro in pulsatile conditions on circular, conical, and slit-like orifices. The calculated ERO was compared with the actual jet cross sectional area derived from the transverse velocity profile at the jet origin. For the purpose of comparison, the "classical" ERO was calculated for all the configurations, angulations, and threshold velocities. The relationship between (Vo/Vr)0.5 was linear (r > 0.98) over a wide range of velocities. The nonhemispheric components were found to modify the constant and not the slope. The mean variation of the calculated ERO was 6.5%. The correlation between the calculated and the actual ERO was very close (>0.97) with slope equal to 0.96. By comparison with the new method, the classical formula gave an underestimation of the ERO that dramatically increased when studying the flow closer to the orifice or in the case of error on the measurement of r. In conclusion, a method using velocity profiles instead of isolated values improves the accuracy of the proximal isovelocity surface area (PISA) method for measuring the ERO. [source]

Effectiveness of Multilevel (Tongue and Palate) Radiofrequency Tissue Ablation for Patients with Obstructive Sleep Apnea Syndrome,

THE LARYNGOSCOPE, Issue 12 2004
David L. Steward MD
Abstract Objectives: The primary objective is to determine the effectiveness of multilevel (tongue base and palate) temperature controlled radiofrequency tissue ablation (TCRFTA) for patients with obstructive sleep apnea syndrome (OSAS). The secondary objective is to compare multilevel TCRFTA to nasal continuous positive airway pressure (CPAP). Study Design and Methods: The study is a controlled case series of one investigator's experience with multilevel TCRFTA for patients with OSAS. Twenty-two subjects with mild to severe OSAS, without tonsil hypertrophy, completed multilevel TCRFTA (mean 4.8 tongue base and 1.8 palate treatment sessions) and had both pre- and posttreatment polysomnography. Primary outcomes included change from baseline in apnea/hypopnea index (AHI), daytime somnolence, and reaction time testing measured 2 to 3 months after TCRFTA. Secondary outcomes included change in other respiratory parameters, OSAS related quality of life, and upper airway size. Comparison of 18 patients treated with TCRFTA for mild to moderate OSAS (AHI > 5 and , 40) is made with 11 matched patients treated with nasal CPAP for mild to moderate OSAS. Results: Multilevel TCRFTA significantly improved AHI (P = .001), apnea index (P = .02), as well as respiratory and total arousal indices (P = .0002 and P = .01). Significant improvement with moderate or large treatment effect sizes were noted for OSAS related quality of life (P = .01) and daytime somnolence (P = .0001), with a trend toward significant improvement in reaction time testing (P = .06), with mean posttreatment normalization of all three outcome measures. Fifty-nine percent of subjects demonstrated at least a 50% reduction in AHI to less than 20. The targeted upper airway, measured in the supine position, demonstrated a trend toward significant improvement in mean cross sectional area (P = .05) and volume (P = .10). Side effects of TCRFTA were infrequent, mild, and self-limited. No significant correlation between pretreatment parameters and outcome improvement was noted. Nasal CPAP resulted in significant improvement in AHI (P = .0004) to near normal levels, with an associated improvement in OSAS related quality of life (P = .02) and a trend toward significant improvement in daytime somnolence (P = .06). Reaction time testing demonstrated no significant improvement (P = .75). No significant differences were seen for change in AHI, OSAS related quality of life, daytime somnolence, or reaction time testing between multilevel TCRFTA and CPAP. Conclusion: Multilevel (tongue base and palate) TCRFTA is a low-morbidity, office-based procedure performed with local anesthesia and is an effective treatment option for patients with OSAS. On average, abnormalities in daytime somnolence, quality of life, and reaction time testing demonstrated improvement from baseline and were normalized after treatment. Polysomnographic respiratory parameters also demonstrated significant improvement with multilevel TCRFTA. [source]

Assessment of fetal liver volume and umbilical venous volume flow in pregnancies complicated by insulin-dependent diabetes mellitus

BJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 11 2003
Simona M. Boito
Objectives To determine fetal liver volume and its relation with umbilical venous volume flow and maternal glycosylated haemoglobin (HbA1c) in pregnancies complicated by diabetes mellitus type I. Design A cross sectional matched control study. Setting Obstetric out patient clinic, Erasmus MC,University Medical Centre, Rotterdam. Population Data from fetuses of diabetic women (n = 32; 18,36 weeks) were compared with data from normal controls (n = 32) matched for gestational age. Methods Umbilical venous cross sectional area (mm2) and time-averaged velocity (mm/s Doppler) were determined for calculation of volume flow (mL/min) and flow per kilogram fetal weight (mL/min/kg). Umbilical artery pulsatility index was determined. Fetal liver volume measurements were obtained using a Voluson 530-D. Main outcome measures Fetal liver volume, umbilical venous volume flow and downstream impedance. Results A statistically significant difference between fetuses of diabetic women and normal controls was found for liver volume (mean [SD]: 45.9 [34.0] vs 38.3 [28.7] mL), abdominal circumference (22.2 [6.6] vs 21.3 [5.6] cm), estimated fetal weight (1162 [898] vs 1049 [765] g) and fetoplacental weight ratio (0.22 vs 0.19) and liver volume/estimated fetal weight ratio (4.13% [0.007] vs 3.62% [0.009]). Umbilical venous volume flow (mL/min) and umbilical artery pulsatility index were not essentially different between the two study groups, but umbilical venous volume flow per kilogram fetal weight was lower (P < 0.05) in the diabetes group (94.3 [26.1] mL/min kg) compared with normal controls (109.5 [28.0] mL/min/kg). A positive correlation existed between fetal liver volume and maternal HbA1c (P = 0.002). Conclusions Measurement of fetal liver volume by three-dimensional ultrasound may play a role in identifying fetal growth acceleration in diabetic pregnancies. Fetal liver volume increase is positively related to maternal HbA1c levels reflecting degree of maternal glycemic control. Fetal liver volume normalised for estimated fetal weight is significantly higher in the fetuses of diabetic women. In the present study, umbilical venous volume flow and fetoplacental downstream impedance are not different between diabetic and normal pregnancies. [source]

Comparison of liver hemodynamics according to doppler ultrasonography in alcoholic patients subtyped by Cloninger classification and non-alcoholic healthy subjects

ACTA NEUROPSYCHIATRICA, Issue 1 2006
Z. Sumru Cosar
Background:, The aim of this study was to search for morphological and hemodynamic changes in hepatic and splanchnic vasculature in alcoholic patients without the signs of hepatic damage and subtyped by Cloninger classification by means of sonography, and compare the subtypes among themselves and with nonalcoholic healthy subjects. Methods:, Thirty alcohol dependent patients and 30 healthy subjects with no alcohol problem or hepatic impairment were included in the study. Patients were subtyped by Cloninger classification and all patients were evaluated by gray-scale and spectral Doppler ultrasound. The diameter of the portal vein, portal venous velocity, peak systolic and end diastolic velocities of hepatic and superior mesenteric arteries were assessed. RI, PI and systolic/diastolic velocity ratios were also calculated. Results:, Portal vein diameter (PV diameter), portal vein cross sectional area (PV area), portal vein velocity (PV PSV), hepatic artery peak systolic velocity (HA PSV), hepatic artery end diastolic velocity (HA EDV), hepatic artery resistive index (HA RI), hepatic artery pulsatility index (HA PI), and systolic/diastolic velocity ratios (HA S/D), superior mesenteric artery peak systolic velocity (SMA PSV), superior mesenteric artery end diastolic velocity (SMA EDV), superior mesenteric artery resistive indices (SMA RI), pulsatility index (SMA PI), and systolic/diastolic velocity rates (SMA S/D) showed no significant difference among the groups (P > 0.01). Although there is no significant difference in PV PSV, HA PSV, SMA PSV, SMA EDV values between the groups, mean values of Type II alcoholics is greater than other groups. Portal vein cross-sectional area was greater in alcoholic patients (Type I, II and III) compared to the control group (P = 0.000). Portal vein velocity, hepatic artery peak systolic and end diastolic velocity, superior mesenteric artery peak systolic and end diastolic velocity were significantly greater in alcoholic patients than in the control group (P < 0.001). No statistical difference was detected between other parameters evaluated. Conclusion:, In alcohol dependent patients, some hemodynamic and morphologic changes occur in hepatic and splanchnic circulation, even before the signs of hepatic damage develop, which can be detected by means of Doppler and gray-scale sonography. But as there is no significant difference between the Doppler ultrasonographic findings among alcoholics subtyped by a Cloninger classification, which is a clinical classification, it suggests that psychiatric classification doesn't show any correlation with biological parameters, and because of this Cloninger classification a psychiatric classification cannot be considered as a characteristic determinative factor in the prognosis of hepatic disorder due to alcohol use. However, higher values of Type II alcoholics can be attributed to the longer alcohol intake of this subtype. [source]

Hyperoxia-induced arterial compliance decrease in healthy man

CLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 1 2005
Pascal Rossi
Summary Introduction:, Oxygen therapy is commonly used in emergency department and intensive care units without careful evaluation of its effects, especially on the haemodynamics and artery characteristics. Materials and methods:, A prospective laboratory study evaluated brachial circulatory effects of normobaric hyperoxia using ultrasonography-Doppler. The study was set in a hospital research laboratory. The subjects were thirteen healthy volunteers. Investigations were performed under normal air ventilation and after 20 min of hyperoxic mixture ventilation using a high concentration mask. Two dimensional images and brachial blood flow velocities were recorded using ultrasonography and pulsed Doppler to study changes in cross sectional area, blood flow, resistance index, and cross-sectional compliance coefficient. Results:, During hyperoxic exposure, mean PaO2 was 372 ± 21 mmHg. A significant decrease of heart rate was observed. Arterial pressures (systolic and diastolic arterial pressures) were not modified. A decrease of cross sectional areas at end diastole and end systole was observed. Pulsed Doppler study showed a decrease of brachial artery blood flow and an increase of the resistance index. Furthermore, a decrease of the cross-sectional compliance coefficient was observed during hyperoxic exposure in all subjects. Conclusion:, This study using two-dimensional ultrasonography and pulsed Doppler could demonstrate an increase in brachial arterial tone and a decrease in brachial blood flow under normobaric hyperoxia. [source]

Effects of detraining on muscle strength and mass after high or moderate intensity of resistance training in older adults

CLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 4 2009
Savvas P. Tokmakidis
Summary This study examined the effects of a 12 weeks detraining period on muscle strength and mass in older adults who had previously participated in a 12 weeks resistance training programme of high [80% of one repetition maximum (1-RM)] or moderate (60% of 1-RM) intensity. Twenty older adults (60,74 years), separated into a high (HI; n = 10; age: 65 ± 5 years) and a moderate (MI; n = 10; age: 66 ± 4 years) intensity resistance training group, were measured in the 1-RM knee extension and flexion strength, and the midthigh cross sectional areas (CSAs) of quadriceps, hamstrings and total thigh before and after a 12 weeks training period as well as after a 12 weeks detraining period. Maximum knee extension and flexion strength and the CSAs of all muscles decreased significantly (P<0·05) with detraining but remained higher (P<0·05) than pretraining levels for both groups. The HI group had a greater decrement (P<0·05) in maximum strength and the CSA of total thigh compared to the MI group but strength levels and the CSA following detraining were higher (P<0·05) for the HI group. The above data suggest that after a short detraining period of 12 weeks, muscle strength and hypertrophy levels of older adults decrease but remain greater than pretraining irrespective of training intensity. Greater declines in muscle strength are observed following HI training but still muscular strength and muscle mass are retained at a higher level than with MI probably due to the higher gains achieved during the training period. [source]