bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of nicorandil on myocardial function and metabolism in the post‐ischaemic reperfused heart with or without inhalation anaesthetics
Authors: Furuya A. , Kashimoto S. , Kumazawa T. 
Published: July 2002

Background: Nicorandil, which is an ATP‐sensitive K channel opener, has been reported to protect the ischaemic myocardium. However, its interaction with inhalation anaesthetics on the ischaemic myocardium has not been well elucidated. So, we have investigated whether isoflurane or sevoflurane modify the effects of nicorandil on cardiac function and metabolism in the rat heart–lung preparation.Methods: Animals were allocated to 4 groups as follows: Control group, no drug; Nic group, nicorandil; Nic+Iso group, nicorandil and isoflurane; Nic+Sev group, nicorandil and sevoflurane. Seven minutes after the start of perfusion, nicorandil was administered and 10 min after the start of perfusion, the heart was rendered globally ischaemic for 10 min, and then the heart was reperfused for 10 min.Results: LVdP/dt max in the Nic group was higher than those in the other groups. Right atrial pressure in the Nic+Iso and Nic+Sev groups was significantly higher than in the Control and Nic groups. Myocardial ATP in the Nic group was higher than in the other groups. DHBA levels in the perfusate in the Nic and Nic+Iso groups were lower than those in the Control and Nic+Sev groups, but those in the Nic+Sev group were higher than those in the other groups.Conclusions: Nicorandil improved post‐ischaemic cardiac function and preserved high‐energy phosphates. However, these beneficial effects of nicorandil were abolished by the combination with isoflurane or sevoflurane. In addition, sevoflurane increased hydroxyl radical formation in the post‐ischaemic reperfused heart.
Bone turnover and cortical bone mineral density in the distal radius in patients with hyperthyroidism being treated with antithyroid drugs for various periods of time
Authors: Oikawa Michio , Kushida Kazuhiro , Takahashi Masaaki , Ohishi Tsuyoshi , Hoshino Hironobu , Suzuki Motohiro , Ogihara Hiroaki , Ishigaki Jitsuhiro , Inoue Tetsuo 
Published: July 2002

OBJECTIVEWhether patients, who have lost bone mass, can be restored to age‐matched control levels by some means is still controversial. We investigated how the thyroid status after antithyroid drug therapy for various periods of time affects bone metabolism in patients with hyperthyroidism by assessing currently used biochemical markers of bone turnover and distal radius bone mineral density (BMD).DESIGN AND PATIENTSThe biochemical markers of bone turnover and BMD at the distal one third of the radius were measured in 79 women with hyperthy‐roidism treated with antithyroid drugs for various periods of time. The patients were divided into two groups according to thyroid function at the time of study: a hyperthyroid group (serum thyroid stimulating hormone (TSH) < 0.4 mU/l) and an euthyroid group (TSH 0.4–4.0 mU/l). Second, each group was further divided according to the duration of therapy: short‐term (less than 3 years ) and long‐term (3 or more years).MEASUREMENTSUrinary type I collagen degradation products (CTx) were measured by the CrossLapsTM ELISA kit. Urinary pyridinoline (Pyr) and deoxypyridinoline (Dpyr) were measured by high performance liquid chromatography (HPLC) after acid hydrolysis. Serum N‐mid osteocalcin (OCN‐mid) was measured by a recently developed enzyme‐linked immunosorbent assay. Serum alkaline phosphatase (ALP) was determined by routine laboratory methods. Bone mineral density (BMD) at the distal one third of the radius was measured using dual energy X‐ray absorptiometry (DEXA; DCS‐600EX, Aloka, Tokyo).RESULTSThere were statistically significant positive correlations of FT3 and FT4 with the biochemical markers of bone turnover. There were significant negative correlations between the biochemical markers and BMD only in patients undergoing long‐term therapy. In a comparison between hyperthyroid and euthyroid groups based on duration of treatment (long‐term and short‐term), and in a comparison without regard for length of treatment (all patients), it was evident that ALP and CTx levels were significantly higher in the hyperthyroid than in the euthyroid groups. Significantly lower BMD Z‐scores in the hyperthyroid group compared to those in the euthyroid group were observed only in patients undergoing long‐term therapy.CONCLUSIONSUrinary type I collagen degradation products were a sensitive marker for evaluating the bone turnover in patients with hyperthyroidism. Our data suggested that it might be important to control the levels of TSH within normal ranges during long‐term antithyroid drug therapy in order to prevent bone loss.
Expression and subcellular location of COX‐2 in human gastric cancer cells
Authors: Ling Li , Kaichun Wu , Yongzhan Nie , Hanping Wu , Chunmei Wang , Daiming Fan 
Published: July 2002

OBJECTIVE: To detect the expression of cyclooxygenase (COX) in human gastric cancer cell lines and determine the subcellular location of its isoforms. METHODS: Immunohistochemistry, reverse transcription–polymerase chain reaction (RT‐PCR), and laser scanning confocal microscopy (LSCM) were used to investigate the expression and distribution of COX. RESULTS: Positive staining for COX‐2 and COX‐1 protein was seen in human gastric cancer cell lines MKN45, SGC7901 and AGS. However, COX‐2 staining was absent and COX‐1 staining was weak in the MGC803 cell line, although COX‐2 mRNA was present in all four cell lines. When compared with COX‐1, COX‐2 was more strongly expressed at both protein and mRNA levels in the gastric cancer cell lines, which was confirmed by double labeling and LSCM. A quantitative analysis of fluorescein intensity indicated that the pixel intensity peak of COX‐2 had a gray scale value of 50–70, while COX‐1 was only 10. The LSCM technique also revealed the presence of COX‐2 in the cytoplasm and nuclear envelope and COX‐1 in the cytoplasm only. CONCLUSIONS: In human gastric cancer cells, COX‐2 is expressed at higher levels than COX‐1 and the different distributions of the two isoforms suggest that their roles in cell function are distinct.
Studies on the expression, induction and mutation of connexin genes in human gastric cancer
Authors: Shourong Shen , Fue Li , Yang Liu , Zhengzhuan Shi , Yiyou Zou , Xichun Zhang , Huihuan Tang 
Published: July 2002

OBJECTIVE: To study: (i) the expression of connexin (Cx) genes; (ii) the effects of inducers on Cx expression; and (iii) the effects of mutations in Cx coding sequences in human gastric cancer. METHODS: Northern blots, reverse transcription– polymerase chain reaction and polymerase chain reaction–single strand conformational polymorphism were the techniques used. RESULTS: There were regular expression patterns of the Cx genes in normal human gastric epithelium, paracancerous tissues and gastric cancers. Retinoic acid (RA) and dimethyl sulfoxide induced the expression of Cx43 in gastric cancer but Cx46 expression was reduced when induced by RA and 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA). There were no mutations found in the Cx43 coding region. CONCLUSIONS: The Cx32 gene might specifically maintain intercellular communication via gap junctions in the gastric epithelium. Cx43 is an inducible gene in gastric cancer cells. The reduced expression of Cx43 is not caused by mutation of the Cx coding region. A hypothesis explaining the variation in Cx gene expression in human gastric cancer is proposed.
Optimizing symptom control across the patient spectrum
Authors: Scadding G. K. 
Published: July 2002

SummaryAllergic seasonal and perennial rhinitis are common diseases that have a considerable adverse impact on the quality of life of the sufferer. Despite the excellent available treatment, the morbidity of allergic rhinitis remains high, because patients often do not seek medical advice and also because physicians tend to underestimate the disruptive problems caused by the disease. In order to improve patient compliance with medication, the diagnosis of allergic rhinitis should be confirmed and the treatment prescribed should be effective with a simple dosage regimen.
Clinical nasal decongestant activity with oral antihistamines
Authors: Howarth P. 
Published: July 2002

SummaryAllergic rhinitis is an inflammatory condition with increasing prevalence in many developed countries. Although first‐generation antihistamines have shown efficacy in the treatment of this disease, they are relatively ineffective for the treatment of nasal blockage. By contrast, studies with newer antihistamines, such as fexofenadine, cetrizine, mizolastine, desloratadine, and azelastine, have shown efficacy in reducing all symptoms of allergic rhinitis, including nasal congestion. This paper focuses on the clinical studies that have been carried out with some of the newer antihistamines and discusses the mechanisms by which they may exert their additional anti‐allergic effects.
Numerical study of the influence of the shell structure of the crystalline lens on the refractive properties of the human eye
Authors: Masajada A. Popiolek 
Published: July 2002

SummaryIn this paper, the numerical model of the refractive properties of the human eye is given. A special account is given of the laminated structure of the crystalline lens. The crystalline lens is presented in the form of hundreds of shells with rotational symmetry, and with the refractive index constant within each shell. The shells have the form of two semi‐ellipsoids joined along the equator. The refractive index increases from the cortical shell to the inner one, according to the exponential dependency. The cornea, approximated by two ellipsoidal surfaces, is added in front of the crystalline lens. A ray‐tracing procedure is applied to study the refractive properties of such a system: refractive power, spherical aberration and energy distribution. The optical properties of the given model are analysed by changing some parameters such as refractive index profile and number of shells. Calculations show that the gradient of the refractive index inside the crystalline lens results in the generation of many focal planes in such an optical system.
Adsorption of hydrated halide ions on charged electrodes. Molecular dynamics simulation
Authors: Glosli James N. , Philpott Michael R. 
Published: July 2002

Constant temperature molecular dynamics has been used to simulate the adsorption of hydrated halide ions X−=F−, Cl−, Br− and I−, and lithium ion Li+ on flat uniformly charged surfaces. The simulations were done with either 214 water molecules and two ions (Li+ and X−) in a box 2.362 nm deep or with 430 water molecules and the two ions in a box 4.320 nm deep. The boxes were periodically replicated in the xy directions. The magnitude of the surface charge on the box ends was ±0.11 e/(nm)2, corresponding to an electric field of 2×107 V/cm. The lateral dimensions of the simulation cell were 1.862 nm×1.862 nm (x×y) in each case. All of the water molecules and ions interacted with the end walls via a weak 9-3 potential. The Stillinger ST2 water model and parameters optimized for alkali halides interacting with the model ST2 water molecule were used in the calculations. Common particles of truncating the interactions at a finite distance (0.82 nm) and switching off Coulomb interactions at small distances were followed. The temperature was set at T=2.411 kJ/mol (290 K). Some of the properties calculated were distribution density profiles for ions and water across the gap important for comparisons with Gouy–Chapman theory, adsorbed ion–water pair correlation functions, and the number of water molecules in the first and second hydration shells of the ions as a function of time. The time spent by a water molecule in the hydration shell was calculated to be approximately ten times longer for lithium than any other ion.
The correlation between distance from the electrode and hydration number was studied and generally found to be pronounced for the larger anions. Comparison of the dynamics of the common ion Li+ for different anions revealed the subtle influence of a transcell interaction in the 2.362 nm thick film. In the given field, the smallest ions Li+ and F− remained fully solvated at all times. Chloride behaved quite differently. Part of the time this ion was far enough away from the electrode to be fully hydrated and part of the time it was in physical contact (i.e., physisorbed) on the electrode with no water molecules interposed between it and the electrode. Bromide favored contact adsorption over full hydration most of the time. Iodide was observed to be contact adsorbed almost all of the time. These simulations provide new insights on the behavior of strongly hydrated ions at surfaces and how the transition from noncontact to ‘‘contact’’ adsorption occurs.
Laboratory experiments on turbulent mixing across sheared density interfaces
Authors: Stephenson Philip , Fernando Harindra J. S. 
Published: July 2002

An experimental study was carried out to investigate turbulent mixing and entrainment across a density interface subjected to velocity shear. The flow configuration consisted of a salinity (stably) stratified two-fluid system with a driven upper turbulent layer and a quiescent lower layer. The experiments were performed in an Odell–Kovasznay tank and the mean flow in the upper layer was generated by using a conventional disk pump. The velocity and salinity measurements were made using a laser-Doppler anemometer and conductivity probes, respectively, and (quantitative) flow visualization was performed using the laser-induced fluorescence LIF technique. The refractive indices of upper and lower layers were matched, using salt and alcohol, to facilitate the use of laser-based flow diagnostic techniques. The measurements show that the rms velocity fluctuation u in bulk of the mixed layer scales well with the mean velocity jump Δu across the interface. The Thorpe, buoyancy, overturning, and integral length scales, as well as the maximum Thorpe displacement in the mixed layer, were also found to be proportional to the depth h of the upper mixed layer.
The structure of the entrainment interface was found to depend strongly on the bulk Richardson number Ri (=Δb h/u2), where Δb is the buoyancy jump across the interfacial layer. At lower Ri, the entrainment occurred rapidly, as in a nonstratified fluid, but as Ri increases, the entrainment rate becomes a strong function of Ri: under the latter conditions, the interfacial wave breaking and Kelvin–Helmholtz instabilities were common features. At still higher Ri, the entrainment rate becomes vanishingly small and the interfacial mixing events were found to be controlled by the molecular diffusive effects. The measurement of the interfacial-layer thickness using LIF shows that it is much thinner than that measured using less-accurate techniques such as traversing probes. The nondimensional rms amplitude of the interfacial distortions at moderate and high Ri was found to be a strong function of Ri. The interfacial instabilities cause the formation of isolated mixing patches within the interface, which, when collapsed, form horizontal intrusions. The experimental measurements were in agreement with theoretical formulations based on scaling arguments.
Strong flows of dilute suspensions of microstructure
Authors: Szeri Andrew J. , Wiggins Stephen , Leal L. Gary 
Published: July 2002

We consider dilute suspensions that have a microstructure that may be characterized by an axial state vector. Examples include axisymmetric particles, line elements of the fluid itself, or, as an approximation, droplets of fluid or polymer molecules. Past studies, in which sufficient conditions for stretch or coherent orientation of the microstructure are obtained for steady flows with homogeneous velocity gradient tensors are shown not to apply to the general situation. Instead, a careful analysis of the microdynamical equations reveals that stretching and orientation of the microstructure by the flow must be analyzed over a time interval. Using techniques from the theory of dynamical systems, a quantitative measure is developed to determine orientations and/or stretched lengths of the microstructure, that are robust and attractive to nearby states. This leads to a strong flow criterion for unsteady flows with inhomogeneous velocity gradient tensors in which the effects of history dependence are apparent.
A particular model system is treated in the case of general two-dimensional flow. The sensitivity of the results to changes in the modeling assumptions is investigated.
The evolution of diffusive thermohaline staircases
Authors: Stegen G. R. , Muench R. D. , Fernando H. J. S. , Ching C. Y. 
Published: July 2002

Diffusive thermohaline staircases have been observed over wide regions of the Northwestern Weddell Sea in the March 1986 AMERIEZ experiments.1 The spatial distribution and temporal evolution of these staircases suggests that these layers may migrate upwards and also may bifurcate into multiple layers. These observations provided the motivation for a laboratory study of the evolution of thermohaline staircases. In the present study, a thermohaline staircase was generated by heating a stable salinity gradient from below. The thicknesses of the convecting layers, heat and salt transports across the interfaces, and migration of the interfaces due to interfacial turbulent mixing were measured. During the experiments, the interfaces and convecting layers evolve with time, ultimately assuming steady positions and thicknesses h.
The experimental measurements of h, away from the bottom boundary, were found to be in good agreement with a theoretical prediction based on the assumption that a balance between the kinetic and potential energies of the turbulent eddies within the convecting layers sets the thicknesses of the convecting layers. Further, the laboratory data showed an excellent agreement with the oceanic data gathered by the previous investigators. Because of buoyancy transport across the interfaces, the stratification in the system weakens and the buoyancy jump Δb across the interfaces reduces. When the interfacial Richardson number Ri=Δbδ/w*2, where δ is the thickness of the interface and w* is the convection velocity in the layers, drops below a critical value Ric, which is about 1.5, the interfaces showed rapid migration to new quasiequilibrium levels, at which they remain stationary until Ri drops below Ric again. Flow visualization studies show that these rapid migrations are caused by engulfment of the interfacial layer fluid by the eddies of the lower, strongly convecting, layers. The experiments also show that, under certain conditions involving low heat fluxes and high density stratifications, heating of a stable salinity gradient does not lead to the formation of a thermohaline staircase structure; a criterion is developed to predict the conditions favorable for their formation. In addition, when the stratification is small and heat flux is high, the convectively mixed layer propagates upward as in a nonstratified fluid and the stratification tends to be destroyed without forming layers. The laboratory results successfully explain some of the field observations, while providing insight into the physics of thermohaline convection.
Homogeneous buoyancy-generated turbulence
Authors: Batchelor G. K. , Canuto V. M. , Chasnov J. R. 
Published: July 2002

If a random and statistically homogeneous density distribution is created in a fluid, a random motion of the fluid is subsequently generated by buoyancy forces. This motion is resisted by viscous stresses, while the density variation is smoothed by molecular diffusion of the relevant scalar property of the fluid. Furthermore, advective mixing generates smaller-scale components of the scalar quantity, increasing the rate of smoothing. If the Reynolds number of the motion is sufficiently large, the motion becomes turbulent in the ordinary sense. Such turbulence may be said to be generated by an ‘‘active’’ conserved scalar quantity. To elucidate the nature of this buoyancy-driven turbulence, we consider an infinite fluid that is initially at rest everywhere, with a given distribution of the conserved scalar quantity. In order to have a well-defined initial state specified by a manageably small number of parameters, the initial distribution of the scalar is assumed to be statistically homogeneous and isotropic, and to be characterized by a single length L, and a measure of the magnitude of the scalar variations, say, the initial root-mean-square scalar fluctuation θ0. The other parameters on which the field of buoyancy-driven turbulence depends are the kinematic viscosity ν, the diffusivity of the conserved scalar quantity D, and the gravitational constant g.
Dimensionless variables are constructed by choosing L as the unit of length and [L/gθ0]1/2 as the unit of time. The choice of these units introduces two dimensionless parameters into the problem, a Reynolds number R=[gθ0L3]1/2/ν and a Schmidt number σ=ν/D. Since analytical treatment of the problem is limited to the special cases where the nonlinear interactions may be neglected (e.g., R and σR≪1), the primary means of inquiry is a numerical simulation of the flow field. We have performed numerical simulations (using a subgrid model) which sample the entire parameter space of the flow. Of particular interest is the asymptotic behavior of the flow as R and σR increase. One observes that a competition arises between the increase in magnitude of the fluid velocity according to the linear equations and the nonlinear generation of small-scale density and velocity fluctuations. The linear analysis predicts that, in dimensionless units, the time tm at which the mean-square velocity fluctuations reach a maximum, as well as the value of this maximum 〈uiui〉m, increases without limit as R and σR increase. In contrast, the results of the numerical simulation show that tm and 〈uiui〉m become independent of R and σR for sufficiently large values of these parameters. The linear amplification of the flow is thus checked by nonlinear effects. Buoyancy-generated turbulence at high Reynolds number has a period of growth from an initial state of rest, lives for a time in which there is a burst of activity, and then dies in consequence of this activity. This example of self-induced mixing can be given a quantitative description which may be useful in other contexts.