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Sectional Area (sectional + area)

Distribution by Scientific Domains

Medical Sciences	69%
Life Sciences	23%

Kinds of Sectional Area

cross sectional area

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]

Clenbuterol antagonizes glucocorticoid-induced atrophy and fibre type transformation in mice

EXPERIMENTAL PHYSIOLOGY, Issue 1 2004
Maria Antonietta Pellegrino
Beta-agonists and glucocorticoids are frequently coprescribed for chronic asthma treatment. In this study the effects of 4 week treatment with beta-agonist clenbuterol (CL) and glucocorticoid dexamethasone (DEX) on respiratory (diaphragm and parasternal) and limb (soleus and tibialis) muscles of the mouse were studied. Myosin heavy chain (MHC) distribution, fibres cross sectional area (CSA), glycolytic (phosphofructokinase, PFK; lactate dehydrogenase, LDH) and oxidative enzyme (citrate synthase, CS; cytochrome oxidase, COX) activities were determined. Muscle samples were obtained from four groups of adult C57/B16 mice: (1) Control (2) Mice receiving CL (CL, 1.5 mg kg,1 day,1 in drinking water) (3) Mice receiving DEX (DEX, 5.7 mg kg,1 day,1s.c.) (4) Mice receiving both treatments (DEX + CL). As a general rule, CL and DEX showed opposite effects on CSA, MHC distribution, glycolytic and mitochondrial enzyme activities: CL alone stimulated a slow-to-fast transition of MHCs, an increase of PFK and LDH and an increase of muscle weight and fibre CSA; DEX produced an opposite (fast-to-slow transition) change of MHC distribution, a decrease of muscle weight and fibre CSA and in some case an increase of CS. The response varied from muscle to muscle with mixed muscles, as soleus and diaphragm, being more responsive than fast muscles, as tibialis and parasternal. In combined treatments (DEX + CL), the changes induced by DEX or CL alone were generally minimized: in soleus, however, the effects of CL predominated over those of DEX, whereas in diaphragm DEX prevailed over CL. Taken together the results suggest that CL might counteract the unwanted effects on skeletal muscles of chronic treatment with glucocorticoids. [source]

Growth Hormone Administration and Exercise Effects on Muscle Fiber Type and Diameter in Moderately Frail Older People

JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 7 2001
James V. Hennessey MD
OBJECTIVE: Reduced muscle mass and strength are characteristic findings of growth hormone deficiency (GHD) and aging. We evaluated measures of muscle strength, muscle fiber type, and cross sectional area in response to treatment with recombinant human growth hormone (rhGH) with or without a structured resistance exercise program in frail older subjects. DESIGN: Placebo-controlled, randomized, double blind trial. SETTING: Outpatient clinical research center at an urban university-affiliated teaching hospital. PARTICIPANTS: Thirty-one consenting older subjects (mean age 71.3 ± 4.5 years) recruited as a subset of a larger project evaluating rhGH and exercise in older people, who underwent 62 quadricep-muscle biopsies. INTERVENTION: Random assignment to a 6-month course of one of four protocols: rhGH administered subcutaneously daily at bedtime, rhGH and a structured resistance exercise program, structured resistance exercise with placebo injections, or placebo injections only. MEASUREMENTS: Muscle biopsy specimens were obtained from the vastus lateralis muscle. Isokinetic dynamometry strength tests were used to monitor individual progress and to adjust the weights used in the exercise program. Serum insulin-like growth factor-I (IGF-I) was measured and body composition was measured using a Hologic QDR 1000W dual X-ray densitometer. RESULTS: The administration of rhGH resulted in significant increase in circulating IGF-I levels in the individuals receiving rhGH treatment. Muscle strength increased significantly in both the rhGH/exercise (+55.6%, P = .0004) as well as the exercise alone (+47.8%, P = .0005) groups. There was a significant increase in the proportion of type 2 fibers between baseline and six months in the combined rhGH treated subjects versus those not receiving rhGH (P = .027). CONCLUSIONS: Our results are encouraging in that they suggest an effect of growth hormone on a specific aging-correlated deficit. IGF-I was increased by administrating rhGH and muscle strength was increased by exercise. The administration of rhGH to frail older individuals in this study resulted in significant changes in the proportions of fiber types. Whether changes in fiber cross-sectional area or absolute number occur with long-term growth hormone administration requires further study. [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]

Structural and Ultrastructural Study of the Intracranial Portion of the Oculomotor, Trochlear and Abducent Nerves in Dog

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 3 2006
J. Vivo
Summary The right intracranial portion of the oculomotor, trochlear and abducent nerves were removed from six adult German shepherd dogs and analysed by light and electron microscopy. In all cases the nerve sectional area was calculated. Unmyelinated and myelinated fibres were analysed and number, diameter and cross-sectional area were calculated. In myelinated fibres, also calculated were the corresponding axon area and diameter, and myelin sheath thickness. The mean number of myelinated fibres was 8543.50 ± 1231.85 being the unmyelinated 1402 ± 241.58 in the oculomotor nerve; 1509 ± 223.17 and 287.67 ± 72.28 in the trochlear nerve and 2473.00 ± 211.41 and 231.25 ± 92.67 respectively in the abducent. The mean diameter was 10.23 ± 0.68 ,m in myelinated and 0.43 ± 0.21 for unmyelinated in oculomotor nerve, 10.53 ± 0.55 ,m and 0.33 ± 0.04 for the trochlear, and 10.45 ± 1.27 ,m and 0.47 ± 0.09 in the abducent nerve respectively. This study reveals that oculomotor, trochlear and abducent nerves of the dog show structural and ultra-structural features similar to the same nerves in other species. [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]

Association between plaque instability, angiogenesis and symptomatic carotid occlusive disease,

BRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 7 2001
R. Mofidi
Background: Angiogenesis is a recognized feature of the atherosclerotic process and has been described in the context of unstable coronary atherosclerotic lesions. The aim of this study was to assess the association between angiogenesis in atherosclerotic carotid plaques and microscopic features of plaque instability, in particular intraplaque haemorrhage. Methods: Consecutive patients undergoing carotid endarterectomy were included. Endarterectomy specimens were divided into their constituent atherosclerotic lesions. Histological sections were prepared and stained with haematoxylin and eosin, and immunohistochemically with an endothelial cell marker (CD34). The quantity of intraplaque haemorrhage was measured in transverse histological sections using computerized image analysis. Microvessel counts were performed in CD34-stained sections and were verified through computerized image analysis. Results: Some 239 atherosclerotic lesions from 73 patients were available for analysis; 73 were early lesions, 74 were raised fibroatheromas and 92 were unstable atherosclerotic plaques. One hundred and fifty lesions were not haemorrhagic; 89 exhibited intraplaque haemorrhage, of which 28 involved less than 50 per cent of the plaque sectional area. There were higher microvessel counts in plaques containing over 50 per cent haemorrhage (P < 0·0001), unstable atherosclerotic lesions (P < 0·0001) and atherosclerotic lesions obtained from symptomatic patients (P < 0·001). Conclusion: There are strong associations between plaque vascularity, quantity of intraplaque haemorrhage and presence of symptomatic carotid occlusive disease. © 2001 British Journal of Surgery Society Ltd [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]

Fluid flow and heat transfer investigations in shell and dimple heat exchangers

INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 5 2005
A. Witry
Abstract Heat transfer and pressure drop characteristics are investigated here using experimental and analytical techniques for a dimple plate heat exchanger. The analysis uses the log mean temperature difference method (LMTD) in all its calculations. Whilest the shell side flow highly resembles the flow over a rough or wavy plate, the tube side passage in these represents the flow over short hexagonal tube banks with the flowing across the sectional areas between the hexagons having the shape of a benzene ring. Local and global experimental measurements are carried out around the heat exchanger. Furthermore, analytical models for both sides of the heat exchanger were obtained from the literature. Reasonable cross match between experimental and analytical results could be obtained. Copyright © 2005 John Wiley & Sons, Ltd. [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]