Biomedical subjects

Ping Wang

Publications and source records attributed to Ping Wang.

At least 271 records · Page 15Linked to original sources

PubMed2003

Chaperones and folding of MHC class I molecules in the endoplasmic reticulum.

In this review we discuss the influence of chaperones on the general phenomena of folding as well as on the specific folding of an individual protein, MHC class I. MHC class I maturation is a highly sophisticated process in which the folding machinery of the endoplasmic reticulum (ER) is heavily involved. Understanding the MHC class I maturation per se is important since peptides loaded onto MHC class I molecules are the base for antigen presentation generating immune responses against virus, intracellular bacteria as well as tumours. This review discusses the early stages of MHC class I maturation regarding BiP and calnexin association, and differences in MHC class I heavy chain (HC) interaction with calnexin and calreticulin are highlighted. Late stage MHC class I maturation with focus on the dedicated chaperone tapasin is also discussed.

Animals↗

PubMed2003

Adrenomedullin and adrenomedullin binding protein-1 downregulate TNF-alpha in macrophage cell line and rat Kupffer cells.

Recent studies have demonstrated that administration of adrenomedullin (AM) and AM binding protein-1 (AMBP-1) maintains cardiovascular stability and reduces mortality in sepsis. However, the mechanism responsible for the beneficial effect of AM/AMBP-1 remains unknown. The aim of this study therefore was to determine whether AM/AMBP-1 directly reduces lipopolysaccharide (LPS)-induced secretion of TNF-alpha from murine macrophage-like cell line RAW 264.7 cells and Kupffer cells isolated from normal rats. TNF-alpha release and gene expression were determined by ELISA and RT-PCR, respectively. The results indicated that LPS increased TNF-alpha production from RAW cells by 38-63-fold in a dose- and time-dependent manner. Although incubation with AM or AMBP-1 alone inhibited LPS-induced TNF-alpha release by 14-22% and 13-22%, respectively, AM and AMBP-1 in combination significantly suppressed TNF-alpha production (by 24-35%). Moreover, the upregulated TNF-alpha mRNA by LPS stimulation was significantly reduced by AM/AMBP-1, but not by AM or AMBP-1 alone. In the Kupffer cells primary culture, AM or AMBP-1 alone inhibited LPS-induced TNF-alpha production by 52% and 44%, respectively. Co-culture with AM/AMBP-1 markedly reduced TNF-alpha production (by 90%). Moreover, AM or AMBP-1 alone decreased TNF-alpha mRNA expression by 41% and 36%, respectively, whereas the combination of AM/AMBP-1 decreased its expression by 63%. These results indicate that AM and AMBP-1 in combination effectively suppress LPS-induced TNF-alpha expression and release especially from primary cultured Kupffer cells, suggesting that the downregulatory effect of AM/AMBP-1 on proinflammatory cytokine TNF-alpha may represent a mechanism responsible for their beneficial effects in preventing inflammatory responses and tissue damage in sepsis.

Adrenomedullin↗

PubMed2003

[Noninvasive monitoring of hypertensive intracerebral hemorrhage and perihematomal tissue edema].

OBJECTIVE: To investigate the dynamic change regularity of intracerebral hemorrhage and perihematomal tissue edema. METHODS: The cerebral electric impedance (CEI) of 100 normal volunteers and 24 patients with hypertensive intracerebral hemorrhage was measured, and the results of measurement were compared with the volumes of hematoma detected by CT. RESULTS: In the normal persons, the CEI values in the left and right sides of cerebral hemispheres were 11.5 +/- 1.3 k(Omega) vs 11.4 +/- 1.8 k(Omega) at the frequency of 20 kHz, 10.2 +/- 1.0 k(Omega) vs 10.3 +/- 1.1 k(Omega) at the frequency of 50 kHz, and 9.1 +/- 0.8 k(Omega) vs 9.2 +/- 0.8 k(Omega) at the frequency of 100 kHz (all P > 0.05). Age, sex and measuring time did not obviously affect the CEI values. In the patients with hypertensive intracerebral hemorrhage the CEI of hematoma side was significantly decreased within 2 days after onset and then increased significantly for more than 10 days. The rate of EI change in the hematoma side within 24 h had a negative correlation with the volume of hematoma (r = -0.895 3, P < 0.01). however, the rate of CEI change in the hematoma side had a positive correlation with the volume of perihematomal edema (r = 0.881 1, P < 0.01). CONCLUSION: CEI is a stable physical parameter reflecting the electrical character of human brain tissue. CEI sensitively reflects the change of hematoma and perihematomal edema, and guides the clinical treatment of cerebral hemorrhage.

Adolescent↗

PubMed2003

Supramodular structure and synergistic target binding of the N-terminal tandem PDZ domains of PSD-95.

PDZ domain proteins play critical roles in binding, clustering and subcellular targeting of membrane receptors and ion channels. PDZ domains in multi-PDZ proteins often are arranged in groups with highly conserved spacing and intervening sequences; however, the functional significance of such tandem arrangements of PDZs is unclear. We have solved the three-dimensional structure of the first two PDZ domains of postsynaptic density protein-95 (PSD-95 PDZ1 and PDZ2), which are closely linked to each other in the PSD-95 family of scaffold proteins. The two PDZs have limited freedom of rotation and their C-terminal peptide-binding grooves are aligned with each other with an orientation preference for binding to pairs of C termini extending in the same direction. Increasing the spacing between PDZ1 and PDZ2 resulted in decreased binding between PDZ12 and its dimeric targets. The same mutation impaired the functional ability of PSD-95 to cluster Kv1.4 potassium channels in heterologous cells. The data presented provide a molecular basis for preferential binding of PSD-95 to multimeric membrane proteins with appropriate C-terminal sequences.

Amino Acid Sequence↗

PubMed2003

Protein tyrosine phosphatase activity regulates endothelial cell-cell interactions, the paracellular pathway, and capillary tube stability.

Protein tyrosine phosphorylation is tightly regulated through the actions of both protein tyrosine kinases and protein tyrosine phosphatases. In this study, we demonstrate that protein tyrosine phosphatase inhibition promotes tyrosine phosphorylation of endothelial cell-cell adherens junction proteins, opens an endothelial paracellular pathway, and increases both transendothelial albumin flux and neutrophil migration. Tyrosine phosphatase inhibition with sodium orthovanadate or phenylarsine oxide induced dose- and time-dependent increases in [14C]bovine serum albumin flux across postconfluent bovine pulmonary artery endothelial cell monolayers. These increases in albumin flux were coincident with actin reorganization and intercellular gap formation in both postconfluent monolayers and preformed endothelial cell capillary tubes. Vanadate (25 microM) increased tyrosine phosphorylation of endothelial cell proteins 12-fold within 1 h. Tyrosine phosphorylated proteins were immunolocalized to the intercellular boundaries, and several were identified as the endothelial cell-cell adherens junction proteins, vascular-endothelial cadherin, and beta-, gamma-, and p120-catenin as well as platelet endothelial cell adhesion molecule-1. Of note, these tyrosine phosphorylation events were not associated with disassembly of the adherens junction complex or its uncoupling from the actin cytoskeleton. The dose and time requirements for vanadate-induced increases in phosphorylation were comparable with those defined for increments in transendothelial [14C]albumin flux and neutrophil migration, and pretreatment with the tyrosine kinase inhibitor herbimycin A protected against these effects. These data suggest that protein tyrosine phosphatases and their substrates, which localize to the endothelial cell-cell boundaries, regulate adherens junctional integrity, the movement of macromolecules and cells through the endothelial paracellular pathway, and capillary tube stability.

Adherens Junctions↗

PubMed2003

Gender dimorphic tissue perfusion response after acute hemorrhage and resuscitation: role of vascular endothelial cell function.

Proestrous female rodents are protected from the deleterious effects of trauma-hemorrhage that are observed in males. We hypothesized that the gender dimorphic outcome after trauma-hemorrhage might be related to gender differences in endothelial function and organ perfusion under such conditions. Male and cycle-matched proestrous female Sprague-Dawley rats underwent a midline laparotomy, hemorrhagic shock (40 mmHg for approximately 90 min), and resuscitation (Ringer lactate, 4x shed blood volume over 60 min). Various parameters were measured 2 h after completion of resuscitation. In the first set of animals, the left ventricle was cannulated and heart performance (maximal rate of left ventricular pressure increase) as well as cardiac output and organ perfusion rates were determined with (85)Sr microspheres. In the second set of animals, aortic vessel rings were harvested and relaxation in response to acetylcholine and nitroglycerin was measured. In the third set of animals, in situ isolated small intestine was perfused to measure the response of the splanchnic vessel bed to acetylcholine and nitroglycerin. After trauma-hemorrhage and resuscitation, females maintained cardiac output and demonstrated increased splanchnic and cardiac perfusion compared with males. Moreover, female intestines did not manifest the endothelial dysfunction that was observed in male intestines after hemorrhagic shock. We conclude that proestrous females show improved endothelial function and tissue perfusion patterns after hemorrhagic shock and that this gender-specific response might be a potential mechanism contributing to the beneficial effects of the proestrus stage under such conditions.

Acetylcholine↗

PubMed2003

A potent, water-soluble and photoinducible DNA cross-linking agent.

Water-soluble DNA cross-linking phenol and biphenol derivatives 3 and 6 have been synthesized by a Mannich reaction. Both of them can cross-link DNA by photoactivation using visible light (wavelength > 400 nm). Compound 6 can cross-link DNA at pH 5.0 and 7.7, whereas no cross-link was observed at pH 10.0. Density functional theory (DFT) calculation indicated that 6 displays a twist structure. Therefore, it could bind to DNA naturally and has potent property to cross-link DNA after photoactivation.

Cross-Linking Reagents↗

PubMed2003

Subcellular localization of beta-arrestins is determined by their intact N domain and the nuclear export signal at the C terminus.

beta-Arrestin1 and beta-arrestin2 play a key role in the regulation of G protein-coupled receptor-mediated signaling, whereas the subcellular distribution of beta-arrestin1 and beta-arrestin2 has been shown to be quite different. In this study, we found that although both beta-arrestin1 and beta-arrestin2 are able to interact with ubiquitin-protein isopeptide ligase (E3) Mdm2, only expression of beta-arrestin2 leads to the relocalization of Mdm2 from the nucleus to the cytoplasm. Further study reveals that beta-arrestin2 but not beta-arrestin1 shuttles between the cytoplasm and nucleus in a leptomycin B-sensitive manner. A hydrophobic amino acid-rich region (VXXXFXXLXL) at the C terminus of beta-arrestin2 was further demonstrated to serve as a nuclear export signal responsible for the extranuclear localization of beta-arrestin2. In the corresponding region of beta-arrestin1, there is a single amino acid difference (Glu instead of Leu in beta-arrestin2), and mutation of Glu to Leu conferred to beta-arrestin1 similar subcellular distribution to that of beta-arrestin2. Moreover, data from a series of deletion mutations demonstrated that the N domain (residues 1-185) was indispensable for the nuclear localization of both beta-arrestins, and the results from a Val to Asp point mutation in the N domain also supported this notion. In addition, our data showed that nucleocytoplasmic shuttling of beta-arrestin2 was required, via protein/protein interaction, for the cytoplasmic relocalization of Mdm2 and JNK3, another well known beta-arrestin2-binding protein. Our study thus suggests that both the nuclear export signal motif and the N domain of beta-arrestins are critical for the regulation of their subcellular localization and that beta-arrestin2 may modulate the function of its binding partners such as Mdm2 and JNK3 by alteration of their subcellular distribution.

Active Transport, Cell Nucleus↗

PubMed2003

Administration of progesterone after trauma and hemorrhagic shock prevents hepatocellular injury.

HYPOTHESIS: Administration of a single dose of progesterone following trauma and hemorrhage in progesterone-deficient rats would ameliorate the inflammatory response and hepatocellular damage. SETTING: A university laboratory. INTERVENTIONS: Ovariectomized female Sprague-Dawley rats (250-350 g; Charles River Laboratories, Wilmington, Mass) underwent a 5-cm midline laparotomy (ie, induction of soft tissue trauma), were bled to a mean arterial blood pressure of 35 mm Hg for about 90 minutes, and then were resuscitated using Ringer lactate solution. Progesterone (25 mg/kg of body weight) or vehicle was administered subcutaneously at the end of resuscitation. In additional animals, Kupffer cells were isolated following trauma, hemorrhage, and resuscitation and treated in vitro with progesterone, lipopolysaccharide, or both. MAIN OUTCOME MEASURES: Six hours following resuscitation, plasma tumor necrosis factor alpha (TNF-alpha) and interleukin 6 (IL-6) levels and liver myeloperoxidase activity were determined. Hepatocellular function (maximum velocity of indocyanine green clearance [Vmax] and the efficiency of the active transport or Michaelis-Menten constant [Km]) and plasma levels of transaminases were measured 20 hours after resuscitation. Kupffer cell IL-6 and TNF-alpha production were assessed. RESULTS: Plasma levels of TNF-alpha, IL-6, aspartate aminotransferase, and alanine aminotransferase, as well as hepatic myeloperoxidase activity were increased, whereas indocyanine green clearance was depressed in vehicle-treated rats following trauma-hemorrhage. Animals treated with progesterone showed significantly reduced levels of the TNF-alpha, IL-6, and transaminases as well as reduced myeloperoxidase activity in the liver. Progesterone-treated animals showed increased Vmax and Kmax values for indocyanine green. In vitro treatment of Kupffer cells with progesterone decreased TNF-alpha production but did not affect the production of IL-6. CONCLUSION: Progesterone administration following trauma-hemorrhage ameliorates the proinflammatory response and, subsequently, the hepatocellular injury via direct action on immunocompetent cells.

Alanine Transaminase↗

PubMed2003

Metformin and gestational diabetes.

Pregnancy increases requirements for insulin secretion, increasing insulin resistance and demands on pancreatic b cells, promoting development of gestational diabetes (GD), particularly in women with preexisting insulin resistance, commonly in women with polycystic ovary syndrome. Preliminary studies suggest that metformin may have the unique potential to prevent the development of GD. We postulate that interventions that reduce insulin resistance and lower requirements for endogenous insulin secretion can preserve b-cell function and prevent the development of type 2 diabetes mellitus.

Clinical Trials as Topic↗

PubMed2003

Polycystic ovary syndrome, the G1691A factor V Leiden mutation, and plasminogen activator inhibitor activity: associations with recurrent pregnancy loss.

Our specific aim was to assess associations of thrombophilia, hypofibrinolysis, and polycystic ovary syndrome (PCOS) with recurrent pregnancy loss (RPL) (>/=3 consecutive pregnancy losses < 20 weeks gestation). Prospective studies were performed in 33 Caucasian women referred for diagnosis and treatment of PCOS who were subsequently found to have RPL and in 16 Caucasian women referred for diagnosis and treatment of RPL, who did not have PCOS. Cases (PCOS-RPL, RPL without PCOS) were compared with controls (116 healthy Caucasian females) for the G1691A Factor V Leiden, G20210A prothrombin, C677T methylenetetrahydrofolate reductase (MTHFR), plasminogen activator inhibitor 4G/5G, and platelet glycoprotein PL A1A2 gene mutations. Cases were compared with controls (44 healthy adult Caucasian females) for serologic coagulation tests including homocysteine, proteins C, S, free S, antithrombin III, anticardiolipin antibodies IgG and IgM, dilute Russel's viper venom time, activated partial thromboplastin time, Factor VIII, Factor XI, lipoprotein (Lp)(a), and plasminogen activator inhibitor activity (PAI-Fx). The 33 Caucasian women with PCOS subsequently found to have RPL were 10% of a cohort of 322 Caucasian women who had >/= 1 previous pregnancy and had been referred for diagnosis and therapy of PCOS over a 4.3-year period. The Factor V Leiden G1691 mutation was present in 6 of 33 women (18%) with PCOS-RPL and in 3 of 16 women with RPL without PCOS (19%) versus 2 of 116 (1.7%) female controls, Fisher's P (p(f)) =.0016, p(f) =.013. The 33 PCOS-RPL cases also differed from the 44 female controls for high PAI-Fx (>21.1 U/mL), 38% versus 8%, p(f) =. 004. The thrombophilic G1691A Factor V Leiden mutation is associated with RPL in women with and without PCOS; hypofibrinolysis (high PAI-Fx) is also associated with RPL in women with PCOS.

Abortion, Spontaneous↗

PubMed2003

An observational study of severe hypertriglyceridemia, hypertriglyceridemic acute pancreatitis, and failure of triglyceride-lowering therapy when estrogens are given to women with and without familial hypertriglyceridemia.

BACKGROUND: We assessed severe hypertriglyceridemia, hypertriglyceridemic acute pancreatitis, and failure of triglyceride-lowering therapy when estrogens were given to 56 women with and without familial hypertriglyceridemia. The 56 women had been consecutively referred to our center over a 3-year period because of triglycerides >400 mg/dl despite diet-drug treatment and/or a history of hypertriglyceridemic acute pancreatitis (AP). Of the 56 women, 17 had received estrogen replacement therapy (ERT), hormone replacement (HRT, n=6), or selective estrogen receptor modulators (SERM, n=1). METHODS: After study at entry, in 56 women (median age, 52 years), 36 with familial hypertriglyceridemia, to lower triglycerides, estrogens and SERMs (hormone treatment, HT) were stopped; a very low fat diet (<15% of calories), gemfibrozil (1.2-1.5 mg/day), and omega-3-fatty acid (4-12 g/day) were started, with restudy 2-4 weeks later. RESULTS: Of the 56 women, 24 (43%) were taking HT at entry, with median fasting triglycerides 1270 mg/dl in the HT group and 1087 mg/dl in the no-HT group. Seventeen women (30%) had a history of AP, nine of whom (53%) were/had been on HT at the development of AP. Significant positive correlates of triglycerides at entry in a stepwise regression model were hemoglobin A(1C) (partial r(2)=10.7%, p<0.05) and an interaction between estrogen use and familial hypertriglyceridemia (partial r(2)=15%, p=0.017). After 2-4 weeks on therapy, median triglycerides in the previous-HT group fell from 1270 to 284 mg/dl (p<0.0001) and in the no-HT group from 1087 to 326 mg/dl (p<0.0001). CONCLUSIONS: Before starting HT, to avoid HT induced hypertriglyceridemic AP and exacerbation of overt or covert familial hypertriglyceridemia, triglycerides must be measured. HT is contraindicated in women with preexisting hypertriglyceridemia (triglycerides> or =500 mg/dl). Triglyceride-lowering diets and drugs often fail in the presence of HT and/or poorly controlled diabetes mellitus, but commonly succeed when HT is stopped and diabetes mellitus is tightly controlled.

Adult↗

PubMed2003

Idiopathic intracranial hypertension: associations with coagulation disorders and polycystic-ovary syndrome.

To better understand potentially reversible causes of idiopathic intracranial hypertension (IIH), also known as pseudotumor cerebri, and an apparent association of IIH with polycystic-ovary syndrome (PCOS), we assessed associations of IIH with coagulation disorders and with PCOS in 38 women with well-documented IIH. Fifteen women were found to have PCOS; 14 of them were obese, with a body-mass index (BMI) greater than 30 kg/m(2), and 10 were extremely obese (BMI > or = 40). Factor VIII concentration was high (>150%) in 9 of 38 (24%) IIH cases, compared with 0 of 40 healthy adults controls (P(f) =.0009). Familial aggregation of high concentrations of factor VIII, associated with thrombophilia, was documented in all 5 of the 9 high-level factor VIII probands' families who were sampled. Activated partial thromboplastin time (APTT) was prolonged (> or =31.5 seconds) in 10 of 38 (26%) IIH cases, compared with 1 of 32 (3%) controls (P(f) =.009) and, in 4 of these cases, was accompanied by the lupus anticoagulant. Plasminogen activator inhibitor activity (PAI-Fx) was high (>21.1 U/mL) in 9 of 38 cases (24%), compared with 1 of 40 controls (3%) (P(f) =.006). Lipoprotein A was high (> or =35 mg/dL) in 13 of 37 cases (35%), compared with 5 of 40 controls (13%) (P(f) =.03). IIH cases did not differ (P >.05) from controls for homocysteine, proteins C and S, free S, antithrombin III, ACLAs IgG and IgM, dilute Russell's viper venom time, Factor XI, factor V Leiden G1691A, G20210A prothrombin, C677T MTHFR, plasminogen activator inhibitor 4G/5G, or platelet glycoprotein PL A1A2 mutations. Exogenous estrogens (n = 23), clomiphene (n = 1), or pregnancy (n = 4) accompanied the first appearance of IIH in 28 women. PCOS and coagulation disorders, often augmented by exogenous estrogens or pregnancy, are associated with IIH.

Adult↗

PubMed2003

Adrenomedullin and adrenomedullin binding protein-1: their role in the septic response.

Adrenomedullin (AM) is a recently discovered, potent vasodilatory peptide with activities including maintenance of cardiovascular and renal homeostasis. Studies have indicated that AM is important in initiating the hyperdynamic response during the early stage of sepsis, and reduction of the vascular effects of AM marks the transition from the initial hyperdynamic phase to the late hypodynamic phase in experimental sepsis. The decreased AM responsiveness in late sepsis may be related to alterations in the AM receptor binding characteristics and/or signaling pathways. Genetic experiments have provided useful information by enhancing AM gene expression. Moreover, a plasma protein which binds AM, adrenomedullin binding protein-1 (AMBP-1), was reported very recently and is just beginning to be investigated as an important modulator in the biphasic septic response. In this regard, our recent results have demonstrated that AMBP-1 synergistically enhanced AM-induced vascular relaxation in both sham and septic animals. It appears that decreased levels of AMBP-1 play a critical role in producing vascular AM hyporesponsiveness during the late stage of sepsis. Furthermore, administration of AM and AMBP-1 in combination prevented the transition from the hyperdynamic to hypodynamic response during the progression of polymicrobial sepsis. Thus, modulation of vascular responsiveness to AM by AMBP-1 may provide a novel approach for the management of sepsis.

Adrenomedullin↗

PubMed2003

Incidence and treatment of metabolic syndrome in newly referred women with confirmed polycystic ovarian syndrome.

In 138 oligo-amenorrheic white women with polycystic ovary syndrome (PCOS) (31+/-9-years-old), our first specific aim was to assess the incidence of the metabolic syndrome and to compare metabolic syndrome abnormalities in women with PCOS to those in the National Health and Nutrition Examination Survey (NHANES) III cohort of 1,887 white women. Our second aim was to determine whether metformin (2.55 g/d) and a diet of 1,500 calories, 26% protein, 44% carbohydrate (42% of carbohydrate complex), 30% fat (polyunsaturate/saturate ratio [P/S]=2/1), would ameliorate metabolic syndrome abnormalities in women with both PCOS and metabolic syndrome. The metabolic syndrome was present in 64 (46%) of the women with PCOS. In these 64 women, there were abnormalities in waist circumference (98%), high-density lipoprotein cholesterol (HDL-C) (95%), blood pressure (70%), triglycerides (56%), and glucose (11%). In these 64 women, mean +/- SD waist circumference was 116+/-15 cm, triglyceride 192+/-152 mg/dL, HDL-C 39+/-7 mg/dL, systolic blood pressure 131+/-13 mm Hg, diastolic blood pressure 83+/-7 mm Hg, and serum glucose 94+/-22 mg/dL. Serum insulin was high (>17 microU/mL) in 42 of the 64 women (66%). After age adjustment, 46.4%+/-4.2% of women with PCOS had the metabolic syndrome (> or =3 abnormalities) versus 22.8%+/-1.1% of NHANES III women, P<.0001 versus 6% of 20 to 29-year-old and 15% of 30 to 39-year-old NHANES III women. Of the 64 women with both PCOS and the metabolic syndrome, 50 had follow-up studies after an average of 6 months on metformin and diet. At 6 months follow-up, mean percent reductions were as follows: body weight 4.7% (111 to 106 kg, P<.0001), triglycerides 14% (197 to 136 mg/dL, P=.0001), systolic blood pressure 5.2% (131 to 124 mm Hg, P=.0002), diastolic blood pressure 6% (83 to 77 mm Hg, P=.0007), and insulin 31% (25 to 17 microU/mL, P<.0001); mean percent HDL-C increased 6% (39 to 41 mg/dL, P=.013). Of these 50 women, 29 had pretreatment baseline abnormal triglycerides (> or =150 mg/dL), 47 had low HDL-C (<50 mg/dL), 26 had high systolic blood pressure (> or =130 mm Hg), 16 had high diastolic blood pressure (> or =85 mm Hg), and 5 had glucose > or = 110 mg/dL. On metformin plus diet at 6 months, triglycerides moved within guidelines in 10 of 29 (34%) women, HDL-C in 6 of 47 (13%), systolic blood pressure in 16 of 26 (62%), diastolic blood pressure in 10 of 16 (63%), and glucose in 3 of 5 (60%). Metformin and diet ameliorate many of the features of the metabolic syndrome, present in 46% of women with PCOS in the current study, and should reduce risk for atherothrombosis and type 2 diabetes mellitus (DM) in PCOS.

Adult↗

PubMed2003

Aerobic biodegradation of trichloroethylene using a consortium of five bacterial strains.

Degradation with an aerobic consortium was used to evaluate the bioremediation trichloroethylene (TCE) as a model substrate. After one week, 228-1186 mg TCE l(-1) was degraded at rates of 20-50 microg TCE l(-1) h(-1). The introduction of 10 mg toluene l(-1) enhanced the degradation rates for TCE when greater than 600 mg l(-1). Using isolated enzymes, a TCE degradation intermediate(s) appears inhibitory to the oxygenase enzymes thereby diminishing the overall degradation.

Bacteria, Aerobic↗

PubMed2003

NMDA-mediated activation of the tyrosine phosphatase STEP regulates the duration of ERK signaling.

The intracellular mechanism(s) by which a cell determines the duration of extracellular signal-regulated kinase (ERK) activation is not well understood. We have investigated the role of STEP, a striatal-enriched tyrosine phosphatase, in the regulation of ERK activity in rat neurons. Glutamate-mediated activation of NMDA receptors leads to the rapid but transient phosphorylation of ERK in cultured neurons. Here we show that activation of NMDA receptors led to activation of STEP, which limited the duration of ERK activity as well as its translocation to the nucleus and its subsequent downstream nuclear signaling. In neurons, STEP is phosphorylated and inactive under basal conditions. NMDA-mediated influx of Ca(2+), but not increased intracellular Ca(2+) from other sources, leads to activation of the Ca(2+)-dependent phosphatase calcineurin and the dephosphorylation and activation of STEP. We have identified an important mechanism involved in the regulation of ERK activity in neurons that highlights the complex interplay between serine/threonine and tyrosine kinases and phosphatases.

Active Transport, Cell Nucleus↗

PubMed2003

Pioglitazone and metformin in obese women with polycystic ovary syndrome not optimally responsive to metformin.

BACKGROUND: In an observational study of 13 women with polycystic ovary syndrome (PCOS) not optimally responsive to metformin diet, we assessed the efficacy and safety of addition of pioglitazone. We also compared these 13 women to 26 women with PCOS, who were responsive to metformin diet, matched by age and by pre- treatment menstrual history and not different by obesity categories. METHODS: Prospectively, as outpatients, with diet constant [1500-2000 calorie (depending on entry body mass index), 26% protein, 44% carbohydrate, 30% fat], metformin (2.55 g/day) was given for 12 months to 39 women, 13 not optimally responsive, 26 responsive to metformin diet, followed by addition of pioglitazone (45 mg/day) for 10 months in the 13 non-responders. Outcome measures included changes in sex hormones, insulin, insulin resistance (IR), insulin secretion, high density lipoprotein cholesterol, weight, and menstrual status. RESULTS: In 13 non-responders, on metformin diet, median serum insulin fell (21 to 16 microIU/ml, P<0.05) and insulin secretion fell from 251 to 200 (P<0.01); weight, dehydroepiandrosterone sulphate (DHEAS), testosterone and IR were unchanged (P> or =0.07). Compared with 14% pre- treatment, on metformin diet, expected menses occurred 46% of the time at 3 months (P=0.05), 38% at 6 months (P=0.07), 27% at 9 months, and 24% at 12 months. In 26 responders, on metformin diet, median weight fell (93 to 87 kg), testosterone fell (50 to 32 ng/dl), insulin fell (26 to 16 microIU/ml), IR fell (5.32 to 3.45) and insulin secretion fell (351 to 271) (P< or =0.017 for all). The occurrence of expected menses in the 26 responders was 2.5-fold higher than in the 13 non-responders (P<0.0001). In 11 non-responders, on pioglitazone + metformin diet over 10 months versus antecedent metformin diet, DHEAS fell (211 to 171 microg/dl, P=0.02), insulin fell (16 to 10 microIU/ml, P= 0.001), IR fell (3.37 to 1.73, P=0.002), insulin secretion fell (217 to 124, P=0.004), sex hormone-binding globulin rose (31 to 43 nmol/l, P=0.006), and HDL cholesterol rose (38 to 42 mg/dl, P=0.003). On pioglitazone + metformin diet, the occurrence of expected menses was 2-fold higher than on metformin diet (P<0.0001). CONCLUSIONS: In women with PCOS who failed to respond optimally to metformin, when pioglitazone was added, insulin, glucose, IR, insulin secretion, and DHEAS fell, HDL cholesterol and sex hormone-binding globulin rose, and menstrual regularity improved, without adverse side-effects.

Adolescent↗