Biomedical subjects

S L Wang

Publications and source records attributed to S L Wang.

At least 37 records · Page 2Linked to original sources

PubMed2001

Solid-state trans-cis isomerization of captopril determined by thermal Fourier transform infrared (FT-IR) microspectroscopy.

Thermal Fourier transform infrared (FT-IR) microspectroscopy was used to investigate the conformational isomerization of captopril in the solid state. The result indicates that the IR peak intensity of captopril for original bands decreased dramatically at 102 degrees C, but for new bands it increased with the rise of temperature. The frequency of C=O stretching mode for carboxylic acid and for amide was located at a higher wavenumber of 1747 cm(-1) and at a lower frequency of 1591 cm(-1) as compared with the general compound, suggesting the existence of trans isomer of captopril in the solid state by intramolecular hydrogen bonding. Beyond 102 degrees C, several new bands at 1720, 1645, and 1610 cm(-1) were observed with the rise of temperature, indicating the coexistence of a cis isomer. However, the cis isomer could transform gradually to the trans isomer after cooling. The thermodynamics of equilibrium mixture of cis/trans isomers were also studied. The trans isomer was more stable than the cis isomer, but the cis isomer was favored at the higher temperature.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed2001

Mortality and causes of death in the WHO Multinational Study of Vascular Disease in Diabetes.

AIMS/HYPOTHESIS: We aimed to examine the mortality rates, excess mortality and causes of death in diabetic patients from ten centres throughout the world. METHODS: A mortality follow-up of 4713 WHO Multinational Study of Vascular Disease in Diabetes (WHO MSVDD) participants from ten centres was carried out, causes of death were ascertained and age-adjusted mortality rates were calculated by centre, sex and type of diabetes. Excess mortality, compared with the background population, was assessed in terms of standardised mortality ratios (SMRs) for each of the 10 cohorts. RESULTS: Cardiovascular disease was the most common underlying cause of death, accounting for 44 % of deaths in Type I (insulin-dependent) diabetes mellitus and 52 % of deaths in Type II (non-insulin-dependent) diabetes mellitus. Renal disease accounted for 21% of deaths in Type I diabetes and 11% in Type II diabetes. For Type I diabetes, all-cause mortality rates were highest in Berlin men and Warsaw women, and lowest in London men and Zagreb women. For Type II diabetes, rates were highest in Warsaw men and Oklahoma women and lowest in Tokyo men and women. Age adjusted mortality rates and SMRs were generally higher in patients with Type I diabetes compared with those with Type II diabetes. Men and women in the Tokyo cohort had a very low excess mortality when compared with the background population. CONCLUSION/INTERPRETATION: This study confirms the importance of cardiovascular disease as the major cause of death in people with both types of diabetes. The low excess mortality in the Japanese cohort could have implications for the possible reduction of the burden of mortality associated with diabetes in other parts of the world.

Cardiovascular Diseases↗

PubMed2001

Risk factors for renal failure: the WHO Mulinational Study of Vascular Disease in Diabetes.

AIMS/HYPOTHESIS: We aimed to examine risk factors for, and differences in, renal failure in diabetic patients from 10 centres. METHODS: Risk factors for renal failure were examined in 3,558 diabetic patients who did not have renal disease at baseline in the WHO Multinational Study of Vascular Disease in Diabetes (WHO MSVDD). RESULTS: In 959 subjects with Type I (insulin-dependent) diabetes mellitus and 2,559 with Type II (non-insulin-dependent) diabetes mellitus, the average follow-up was 8.4 years (+/- 2.7). By the end of the follow-up period 53 patients in the Type I diabetic group and 134 patients in the Type II diabetic group had developed renal failure (incidence rate 6.3:1,000 person years). Increasing age and duration of diabetes were associated with renal failure in Type II and Type I diabetes. In Type II diabetes duration of diabetes was a more important risk factor than age. In both Type I and Type II diabetic retinopathy and proteinuria were strongly associated with renal failure. Systolic blood pressure was associated with renal failure in Type I but not in Type II diabetic patients. ECG abnormalities at baseline, self-reported smoking and cholesterol were not associated with renal failure. Triglycerides were measured in a subset of centres. Among those with Type II, but not Type I diabetes, triglycerides were associated with renal failure independently of systolic blood pressure, proteinuria or retinopathy. In Type II diabetes fasting plasma glucose was associated with renal failure independently of other risk factors. CONCLUSION/INTERPRETATION: We have confirmed the role of proteinuria and retinopathy as markers of renal failure and the importance of hyperglycaemia in renal failure in Type I and Type II diabetes. Plasma triglycerides seem to be an important predictor of renal failure in Type II diabetes. In Type I diabetes systolic blood pressure is an important predictor of renal failure.

Blood Glucose↗

PubMed2001

Risk factors for cardiovascular mortality and morbidity: the WHO Mutinational Study of Vascular Disease in Diabetes.

AIMS/HYPOTHESIS: We aimed to examine the associations between classic cardiovascular risk factors and diabetes specific factors and the incidence of fatal and non-fatal end-points in a large cohort of diabetic patients. METHODS: A cohort of 4,743 diabetic patients participating in the WHO Multinational Study of Vascular Disease in Diabetes (WHO MSVDD) has been followed up for about 12 years and the incidence of fatal and non-fatal cardiovascular disease outcomes assessed. RESULTS: The importance of blood pressure, serum cholesterol and proteinuria as predictors for cardiovascular disease mortality, fatal and non-fatal myocardial infarction and stroke is confirmed for patients with Type I (insulin-dependent) and Type II (non-insulin-dependent diabetes mellitus. Serum triglyceride was associated with cardiovascular disease death in Type II diabetes and in women with Type I diabetes and with MI incidence in Type II diabetes and stroke in Type II diabetic women. Fasting plasma glucose was associated with cardiovascular disease death, incidence of myocardial infarction and stroke in Type II diabetes only. In Type II diabetes, multivariate analysis confirmed that fasting plasma glucose was related to cardiovascular disease mortality independent of other risk factors. The independent relation of triglyceride to cardiovascular disease death was statistically significant only for Type II diabetic men. The presence of retinopathy was related to cardiovascular disease death and incidence of myocardial infarction in both types of diabetes and to stroke in Type II diabetes. CONCLUSION/INTERPRETATION: This large cohort study shows that the assessment of cardiovascular disease risk in diabetes must include 'diabetes-related' variables such as glycaemic control, proteinuria and retinopathy, as well as the classic risk factors, blood pressure, smoking and dyslipidaemia. [Diabetologia

Blood Glucose↗

PubMed2001

Emission spectra studies on the hydrogen-bonding complexes between p-methoxy-2-styrylquinoline and acids.

The ground and excited state interactions between p-methoxy-2-styrylquinoline (2-StQ-OMe) and different protic acids with various acid concentrations were studied in different media. Emission bands due to the hydrogen bonding complex, protonation complex and aggregation or solid complex were observed for the first time, in n-hexane. The different reaction pathways were controlled by the solvent polarity and the concentrations of the protic acid. The acidity of acid was also important to the acid-base complex.

Acids↗

PubMed2001

Comparison of comfort and local complications after cardiac catheterization.

The purpose of this study was to compare the effects of 4 hours of bed rest versus 6 hours of bed rest on patients' safety, comfort, and satisfaction levels. Using a quasi-experimental design, the authors studied 118 left-heart catheterization patients who were randomly assigned to 4 hours or 6 hours of bed rest. Among the study participants, only 1 in the 6-hour group had significant bleeding. There were no complications in the 4-hour group. There were no statistically significant differences between the two groups on any of the other study variables. Given the lack of significant complications for the 4-hour group and similar comfort levels for both study groups, these findings suggest the feasibility of reducing the standard period of postcatheterization bed rest from 6 hours to 4 hours, thereby possibly lowering the cost of the outpatient procedure.

Cardiac Catheterization↗

PubMed2001

Reaction kinetics of solid-state cyclization of enalapril maleate investigated by isothermal FT-IR microscopic system.

To investigate the reaction kinetics of the solid-state degradation process of enalapril maleate, a Fourier transform infrared microspectroscope equipped with thermal analyzer (thermal FT-IR microscopic system) was used. The isothermal stability study was conducted at 120-130 degrees C for 1-2 h and changes in the three-dimensional plots of the IR spectra of enalapril maleate with respect to heating time were observed. The study indicates that the bands at 1649, 1728, and 1751 cm(-1) assigned to intact enalapril maleate gradually reduced in peak intensity with heating time. However, the peak intensities at 1672 and 1738 cm(-1) (due to enalapril diketopiperazine (DKP) formation) and at 3250 cm(-1) (corresponding to water formation) gradually increased with heating time. The solid-state diketopiperazine formation and the degradation process of enalapril maleate via intramolecular cyclization were found to be simultaneous. The isothermal decomposition curves were sigmoidal and were characterized by induction and acceleration periods, indicating the presence of autocatalytic solid-state decompositions. Moreover, the power-law equation (n = 1/4) was found to provide the best fit to the kinetics of decomposition. This isothermal FT-IR microscopic system was easily used to investigate the degradation of enalapril maleate and the concomitant formation of DKP. The solid-state reaction of enalapril maleate required an activation energy of 195+/-12 kJ/mol to undergo the processes of decomposition and intramolecular cyclization.

Algorithms↗

PubMed2001

cDNA library screening using the SOS recruitment system.

The SOS recruitment system (SRS), a recently developed method for detecting protein-protein interactions, provides an attractive alternative to identify biologically important protein interactions. In SRS, the protein-protein interactions take place in the cytoplasm instead of the nucleus, as is the case in the conventional two-hybrid system. Although the SRS has overcome some of the disadvantages of the conventional two-hybrid system, it still has several problems and limitations. Here, we describe a new protocol for SRS library screening. A new combination of growth media to avoid the tedious step of replica plating greatly increases the number of independent colonies in a single library screening. Furthermore, we designed a pair of ras-specific primers and a one-step simple PCR to rule out the most abundant false positive, the mammalian ras cDNA, in SRS library screening.

Animals↗

PubMed2001

Distribution of nitric oxide synthase in stomach myenteric plexus of rats.

AIM: To study the distribution of nitric oxide synthase (NOS) in rat stomach myenteric plexus. METHODS: The distribution of NOS in gastric wall was studied in quantity and location by the NADPH-diaphorase (NDP) histochemical staining method and whole mount preparation technique. RESULTS: NOS was distributed in whole stomach wall, most of them were located in myenteric plexus, and distributed in submucosal plexus.The shape of NOS positive neurons was basically similar, most of them being round and oval in shape. But their density, size and staining intensity varied greatly in the different parts of stomach. The density was 62+/-38 cells mm(2) (antrum), 43+/-32 cells/mm(2) (body), and 32+/-28 cells mm(2) (fundus), respectively. The size and staining intensity of NOS positive neurons in the fundus were basically the same, the neurons being large and dark stained, while they were obviously different in antrum. In the body of the stomach, the NOS positive neurons were in an intermediate state from fundus to antrum. There were some beadlike structures which were strung together by NOS positive varicosities in nerve fibers, some were closely adherent to the outer walls of blood vessels. CONCLUSION: Nitric oxide might be involved in the modulation of motility, secretion and blood circulation of the stomach, and the significant difference of NOS positive neurons in different parts of stomach myenteric plexus may be related to the physiologic function of stomach.

Animals↗

PubMed2001

[Development of Triticum aestivum-Haynaldia villosa 6VS ditelosomic substitution line via phlb mutant].

Chinese Spring phlb mutant (C S phlbphlb) was crossed to Triticum aestivum-Haynaldia villosa 6V (6A) alien substitution line and F1 back was crossed with C. S phlbphlb. One LV 02 with varied H. villosa 6V chromosome and one LV 02-01 with 40 T. aestivum chromosome, one H. villosa 6V and 6VS chromosome were screened in BC1F1 and BC1F2 respectively by C-banding and the fluorescence in situ hybridization (FISH). In segregated generation of LV 02-01, eight T. aestivum-H. villosa 6VS ditelosomic substitution lines were screened by FISH and C-banding.

Chromosome Banding↗

PubMed2001

[Experimental study of allogenic tendon with sheath grafting in chicken].

OBJECTIVE: To investigate availability of deep freeze stored allogenic tendon with sheath grafting in repairing the tendon and sheath defect in the II area of flexor digitorum tendon. METHODS: Sixty chickens with tendon and sheath defect were divided into 2 groups randomly, group A was treated with allogenic grafting and group B was treated with autogenic grafting, these two groups were divided into two subgroups respectively, they were, group A1 allogenic tendon with whole sheath grafting, group A2 allogenic tendon with partial sheath grafting, group B1 autogenic tendon with whole sheath grafting and group B2 autogenic tendon with whole sheath grafting. All the allogenic grafts were treated by deep freeze. Histomorphological study, histoimmunological study and slipping function of the grafts were measured after operation. RESULTS: In group A1 and B1, the local reaction was sever, the nutrition of tendon graft was barricaded by the whole sheath resulting in adhesion, degeneration and necrosis. In group A2 and B2, the tendon graft healed well and little adhesion existed between tendon and sheath. The results showed that there were significant differences between tendon grafting with whole sheath and tendon grafting with partial sheath. CONCLUSION: Deep freeze store can reduce the immunogenicity of allogenic tendon with sheath. Allogenic tendon with partial sheath grafting can be used as a new biological material for repairing the tendon and sheath defect.

Animals↗

PubMed2001

Expression of Ca(2+)/calmodulin-dependent protein kinase IV (caMKIV) messenger RNA during murine embryogenesis.

Ca(2+)/calmodulin-dependent protein kinase IV (CaMKIV) is a monomeric, multifunctional serine/threonine protein kinase that is expressed in subanatomic regions of the central and peripheral nervous system, T lymphocytes, and male germ cells. It is frequently localized to the nucleus, where it serves as a mediator of Ca(2+)-dependent gene expression. Although CaMKIV expression in the adult rat central nervous system and thymus has been described, little is known about the embryonic expression of murine CaMKIV. Here we report a thorough embryonic expression study of CaMKIV mRNA from embryonic day 9.5 through postnatal day 1. Expression patterns during embryonic development are significantly different from those of adults, suggesting specific roles for CaMKIV during development. Regions of high CaMKIV mRNA expression include thymic and bone cartilage primordia as well as specific cranial nerve ganglia (trigeminal, vestibulocochlear, and glossopharyngeal), thalamus, and dorsal root ganglia. This pattern of expression is chronologically consistent with periods of extensive cellular differentiation, proliferation, or neuronal survival selection and shows a predilection for neural crest-derived cells. These trends, along with recent studies in the CaMKIV null mouse, suggest that CaMKIV may play an important physiological role in cellular differentiation during embryogenesis.

Animals↗

PubMed2001

[Determination of intestinal trefoil factor in burned rats by reversed-phase high performance liquid chromatography].

A reversed-phase high performance liquid chromatographic method was established for determination of intestinal trefoil factor (ITF) in burned rats. The analysis was carried out on a Hypersil C4 column (30 nm, 5 microns, 4.6 mm i.d. x 250 mm) with gradient elution of acetonitrile-trifluoroacetic acid-water solution at a flow rate of 1 mL/min and detected by a UV detector at 214 nm. The volume proportion of trifluoroacetic acid in water is 0.1% and the volume proportion of acetonitrile in mobile phase ranged from 19.5% to 42.0%. The linear range of the method was 1 mg/L-100 mg/L with relative coefficient of 0.9989. The minimum detection limit was 0.5 mg/L. The recovery of ITF added ranged between 93.95% and 105.90%. The intra-day and inter-day RSD of ITF were less than 5.33% and 6.10% respectively. This method is precise, accurate and can be used for the determination of ITF in intestinal mucosal of burned rats. Therefore, it is helpful in the research of comparing the effects of enteral feeding and parenteral nutrition on ITF expression.

Animals↗

PubMed2000

The Drosophila caspase DRONC cleaves following glutamate or aspartate and is regulated by DIAP1, HID, and GRIM.

The caspase family of cysteine proteases plays important roles in bringing about apoptotic cell death. All caspases studied to date cleave substrates COOH-terminal to an aspartate. Here we show that the Drosophila caspase DRONC cleaves COOH-terminal to glutamate as well as aspartate. DRONC autoprocesses itself following a glutamate residue, but processes a second caspase, drICE, following an aspartate. DRONC prefers tetrapeptide substrates in which aliphatic amino acids are present at the P2 position, and the P1 residue can be either aspartate or glutamate. Expression of a dominant negative form of DRONC blocks cell death induced by the Drosophila cell death activators reaper, hid, and grim, and DRONC overexpression in flies promotes cell death. Furthermore, the Drosophila cell death inhibitor DIAP1 inhibits DRONC activity in yeast, and DIAP1's ability to inhibit DRONC-dependent yeast cell death is suppressed by HID and GRIM. These observations suggest that DRONC acts to promote cell death. However, DRONC activity is not suppressed by the caspase inhibitor and cell death suppressor baculovirus p35. We discuss possible models for DRONC function as a cell death inhibitor.

Amino Acid Sequence↗

PubMed2000

Selective malformation of the splenic white pulp border in L1-deficient mice.

Lymphocytes enter the splenic white pulp by crossing the poorly characterized boundary of the marginal sinus. In this study, we describe the importance of L1, an adhesion molecule of the Ig superfamily, for marginal sinus integrity. We find that germline insertional mutation of L1 is associated with a selective malformation of the splenic marginal sinus. Other splenic structures remain intact. Immunofluorescence analysis of the extracellular framework of the spleen, using an Ab to laminin, reveals that L1 knockout mice have an irregularly shaped, discontinuous white pulp margin. Electron microscopic analysis shows that it is associated with bizarrely shaped marginal sinus lining cells at the periphery of the white pulp. These abnormalities correlate with the localization of L1 in normal mice in that L1 is normally expressed on marginal sinus lining cells at the white pulp border. These L1-immunopositive lining cells coexpress high levels of mucosal addressin cell adhesion molecule-1 and vimentin, indicating that they are of fibroblastic lineage and express a well-characterized addressin. Our findings are the first to implicate L1 in splenic lymphoid architectural development. Moreover, these findings help define the poorly characterized sinusoidal boundary across which mononuclear cells cross to enter the splenic white pulp.

Animals↗

PubMed2000

Bile acid induction of cytokine expression by macrophages correlates with repression of hepatic cholesterol 7alpha-hydroxylase.

In the studies reported herein, we show that two complementary experimental models: inbred strains of mice (i.e. C57BL/6 and C3H/HeJ), and a differentiated line of rat hepatoma cells (i.e. L35 cells), require the activation of cytokines by monocyte/macrophages to display bile acid negative feedback repression of cholesterol 7alpha-hydroxylase (CYP7A1). Feeding a bile acid-containing atherogenic diet for 3 weeks to C57BL/6 mice led to a 70% reduction in the expression of hepatic CYP7A1 mRNA, whereas no reduction was observed in C3H/HeJ mice. The strain-specific response to repression of CYP7A1 paralleled the activation of hepatic cytokine expression. Studies using cultured THP-1 monocyte/macrophages showed that the hydrophobic bile acid chenodeoxycholate, a well established potent repressor of CYP7A1, induced the expression of mRNAs encoding interleukin 1 (IL-1) and tumor necrosis factor alpha (TNFalpha). In contrast, the hydrophilic bile acid ursodeoxycholate, which does not repress CYP7A1, did not induce cytokine mRNA expression by THP-1 cells. Chenodeoxycholate activation of cytokines by THP-1 cells was blocked by the peroxisome proliferator-activated receptor gamma agonist rosiglitazone. The expression of cytokines (e.g. IL-1 and TNFalpha) by THP-1 cells paralleled with the ability of these cells to produce conditioned medium that when added to rat L35 hepatoma cells, repressed CYP7A1. Moreover, rosiglitazone, which blocks cytokine activation by macrophages, also blocked the repression of CYP7A1 normally exhibited by C57BL/6 mice fed the bile acid-containing atherogenic diet. The combined data indicate that the activation of cytokines may mediate CYP7A1 repression caused by feeding mice an atherogenic diet containing bile acids.

Animals↗

PubMed2000

One or more labile proteins regulate the stability of chimeric mRNAs containing the 3'-untranslated region of cholesterol-7alpha -hydroxylase mRNA.

Multiple AUUUA elements similar to those that regulate the degradation of several different mRNAs are conserved in the 3'-untranslated region (3'-UTR) of cholesterol-7alpha-hydroxylase (CYP7A1) mRNAs from several species. We examined if stabilization of mRNA decay could account for the >20-fold increase in the expression of CYP7A1 mRNA without a detectable change in transcription following dexamethasone treatment of rat hepatoma cells (L35 cells). Following RNA polymerase II-dependent transcription block or protein synthesis block, the decay of CYP7A1 mRNA displayed a short half-life ( approximately 30 min). Control experiments showed that in cells pre-treated with a RNA polymerase II inhibitor, dexamethasone had no detectable effect on CYP7A1 mRNA decay. Stable expression of luciferase reporter mRNAs in L35 cells showed that the CYP7A1 3'-UTR was required to observe a dexamethasone induction. To examine the hypothesis that a labile protein is required for dexamethasone-induced mRNA stabilization, cells were stably transfected with a tetracycline-repressible promoter that drives the expression of a green fluorescent protein analogue (ECFP) with or without the 3'-UTR of CYP7A1. Cells expressing ECFP with the 3'-UTR of CYP7A1 displayed a 3-fold dexamethasone induction of ECFP mRNA, whereas cells expressing ECFP without the 3'-UTR did not. Moreover, specific block of the transcription of ECFP containing the 3'-UTR by adding the tetracycline analogue doxycycline clearly displayed dexamethasone-induced stabilization of mRNA decay. These data provide compelling evidence that a putative labile protein and the 3'-UTR of CYP7A1 act together to decrease the rate of CYP7A1 mRNA degradation.

3' Untranslated Regions↗

PubMed2000

Crystal and molecular structure of an eight-coodinate N-methyltetraphenylporphyrin complex: diacetato(N-methyl-meso-tetraphenylporphyrinato)thallium(III).

The crystal structure of diacetato(N-methyl-meso-tetraphenylporphyrinato)thallium(III), Tl(N-Me-tpp)(OAc)2 (1), was established, and the coordination sphere around the Tl3+ ion is described as an eight-coordinate square-based antiprism in which two cis chelating bidentate OAc- groups occupy two apical sites. The plane of the three pyrrole nitrogen atoms (i.e., N(1), N(3), N(4)) strongly bonded to Tl3+ is adopted as a reference plane 3N. The pyrrole N(2) ring bearing the methyl group (i.e., C(45)H3) is the most deviated one from the 3N plane, making a dihedral angle of 21.4 degrees, whereas smaller angles of 9.1 degrees, 7.1 degrees, and 0.9 degree occur with pyrroles N(1), N(3), and N(4), respectively. Because of its larger size, the thallium(III) ion Tl3+ is considerably out of the 3N plane; its displacement of 1.17 A is in the same direction as that of the two apical OAc- ligands. The intermolecular acetate exchange process for 1 in THF-d8 solvent is examined through 1H NMR temperature-dependent measurements. In the slow-exchange region, the methyl and carbonyl carbons of the OAc- groups in 1 are separately located at delta 18.6 [3J(Tl-13C) = 405 Hz] and 170.8 [2J(Tl-13C) = 334 Hz] at -80 degrees C, respectively.

Journal Article↗