bluuebunny/crossref_metadata_2025 huggingface dataset:
Observation of Sympathomimetic Effect of Ear Acupuncture Stimulation for Body Weight Reduction
Authors: Shen Ein-Yiao , Hsieh Ching-Liang , Chang Yung-Hsien , Lin Jaung-Geng
Published: November 2009

Ear acupuncture stimulation has been used for body weight reduction as early as the 1970s. Several hypotheses have been proposed in literature regarding its mechanism of action, among which are the effects of the stimulation of the hypothalamic satiety center on decreased neuropeptide Y production. Here, we present another possible mechanism to account for the temporary and short-term effects of ear acupuncture stimulation in the treatment of obesity, the sympathetic effects of the autonomic nervous system. 14 female volunteers underwent a randomized clinical trial of the ear acupuncture stimulation. A prospective, sham-point control, crossover study was performed with two sequential four-week stimulation periods separated by a two-week washout interval. The clinical features of and effects on the autonomic nervous system were recorded and analyzed. Decreased body weight was observed in both the experimental and the control groups in the first 4 weeks of stimulation. Sympathomimetic effects were also noted in both groups. Whereas the sympathomimetic effects and body weight reduction were sustained in the experimental group in the second 4 weeks of stimulation, such effects were not observed in the control group. Some sympathomimetic effects were noted in both the experimental and the control groups initially. This effect remained apparent in the experimental group in sequential stimulation but was lost in the control group. Consequently, we believe that sympathomimetic effects may account for the reduction in body weight by temporarily increasing basal metabolic rate and decreasing appetite, but the body may regain weight after the termination of such effects. Accordingly, the combination of an optimal exercise and diet program with repeated acupoint therapy may be necessary to maintain a healthy body weight.
The Effect of Tanshinone IIA on the Cardiovascular System in Ovine Fetus in Utero
Authors: Mao Caiping , Zhang Yifan , Zhang Yuying , Cao Li , Shao Huan , Wang Liping , Zhu Liyan , Xu Zhice
Published: November 2009

This was the first study to determine the effect of tanshinone IIA (an active ingredient in herb Danshen) on fetuses in utero under unstressed condition. Tanshinone IIA or 0.9% NaCl as control was intravenously (i.v.) administrated into pregnant ewes. Both maternal and fetal blood were analyzed for PO 2, PCO 2, SO 2%, hemoglobin, hemotecrit, glucose, lactic acid, Na +, K +, and Cl - concentrations. Maternal and fetal heart functions were assessed by examining cardiac enzymes and cardiovascular responses. The results showed that tanshinone IIA did not alter the blood values in ewes and fetuses. Cardiac enzyme activities related to the heart remained unchanged. In cardiovascular experiments, no alternation in maternal blood pressure by tanshinone IIA was observed. However, fetal systolic pressure was slightly and significantly increased following i.v. tanshinone IIA into the mothers, while fetal diastolic pressure, mean arterial pressure, and heart rate were not changed. The results demonstrated that tanshinone IIA used during the last third of gestation did not cause the biochemical changes related to cardiac functions in both maternal and fetal sheep. Fetal oxygen metabolism remained stable in utero, providing new information for clinical use of the herb in pregnancy. That tanshinone IIA increased fetal systolic pressure may open new opportunities to study the herb in fetal medicine.
Activation of Nitric Oxide/cGMP/PKG Signaling Cascade Mediates Antihypertensive Effects ofMuntingia calaburain Anesthetized Spontaneously Hypertensive Rats
Authors: Shih Cheng-Dean
Published: November 2009

We previously reported that the leaf extract of Muntingia calabura L. (Tiliaceae) exerts a potent hypotensive effect in the normotensive rats. The antihypertensive activity of this plant extract, however, is currently unknown. In the present study, we investigated the antihypertensive effects of the n-butanol soluble fraction (BSF) from methanol leaf extract of M. calabura in spontaneously hypertensive rats (SHR), and delineated is underlying mechanisms. The intravenous bolus administration of the BSF (10–100 mg/kg) of M. calabura produced biphasic dose-related antihypertensive and bradycardiac effects in SHR. The BSF-induced initial cardiovascular depressive effects lasted for 10 min, and the delayed effects commenced 40 min and lasted for at least 120 min postinjection. These cardiovascular depressive effects of BSF treatments were greater in SHR than in normotensive Wistar-Kyoto (WKY) rats. Both the initial and delayed antihypertensive and bradycardiac effects of BSF (25 mg/kg, i.v.) in SHR, were significantly blocked by pretreatment with a nonselective nitric oxide ( NO ) synthase (NOS) inhibitor, a soluble guanylyl cyclase (sGC) inhibitor, or a protein kinase G (PKG) inhibitor. Moreover, the initial effects of BSF in SHR were inhibited by pretreatment with a selective endothelial NOS (eNOS) inhibitor; whereas the delayed effects were attenuated by a selective inducible NOS (iNOS) inhibitor. These results indicate that the BSF from the leaf of M. calabura elicited both transient and delayed antihypertensive and bradycardiac actions in SHR, which might be mediated through NO generated respectively by eNOS and iNOS. Furthermore, activation of sGC/cGMP/PKG signaling pathway may participate in the M. calabura-induced biphasic cardiovascular effects.
Effect of Dipsaci Radix on Hind Limb Muscle Atrophy of Sciatic Nerve Transected Rats
Authors: Jung Hyuk-Sang , Noh Chung-Ku , Ma Sun-Ho , Hong Eun Ki , Sohn Nak-Won , Kim Yoon-Bum , Kim Sung-Hoon , Sohn Youngjoo
Published: November 2009

It was reported that Dipsaci radix (DR) has a reinforcement effect on the bone-muscle dysfunction in the oriental medical classics and the experimental animal studies. The muscle atrophy was induced by unilateral transection of the sciatic nerve of the rats. Water-extract of DR was used as treatment once a day for 12 days. The muscle weights of the hind limb, atrophic changes, glycogen contents, compositions and cross-section areas of muscle fiber types in soleus and medial gastrocnemius were investigated. Muscle fiber type was classified to type-I and type-II with MHCf immunohistochemistry. Furthermore, Bax and Bcl-2 expressions were observed with immunohistochemiatry. DR treatment significantly increased muscle weights of soleus, medial gastrocnemius, lateral gastrocnemius, and posterior tibialis of the damaged hind limb. DR treatment reduced apoptotic muscle nuclei and hyaline-degenerated muscle fibers in soleus and medial gastrocnemius of the damaged hind limb. DR treatment also significantly increased glycogen contents in medial gastrocnemius of the damaged hind limb. DR treatment significantly attenuated the slow-to-fast shift in soleus of the damaged hind limb but not in medial gastrocnemius. DR treatment significantly increased cross-section areas of type-I and type-II fibers in soleus and medial gastrocnemius of the damaged hind limb. In soleus and medial gastrocnemius, DR treatment significantly reduced Bax positive muscle nuclei in the damaged hind limb. These results suggest that DR treatment has an anti-atrophic effect and an anti-apoptotic effect against myonuclear apoptosis induced by the peripheral nerve damage.
The Hypocholesterolemic Effects ofCistanche tubulosaExtract, a Chinese Traditional Crude Medicine, in Mice
Authors: Shimoda Hiroshi , Tanaka Junji , Takahara Yoshiyuki , Takemoto Kazuhisa , Shan Shao-Jie , Su Muh-Hwan
Published: November 2009

The roots of Cistanche (C.) tubulosa (Orobanchaceae), a parasitic plant that grows in the Taklamakan desert, are traditionally used as medicines and foods in China. We prepared aqueous ethanol extract (CTE) from the roots of C. tubulosa and its hypocholesterolemic effect was evaluated. Using gene chip and RT-PCR analysis of the livers of mice given CTE (400 mg/kg) for 14 days, we found mRNA expression of molecules related to cholesterol transport [apolipoprotein B and very low density lipoprotein (VLDL) receptor] and metabolism [cytochrome P450 side chain cleave (SCC) and steroid 5α-reductase 2] were up-regulated. The administration of CTE (400 mg/kg) for 14 days significantly suppressed serum cholesterol elevation in high cholesterol diet-fed mice. The mRNA expressions of VLDL receptor and cytochrome P450 SCC were significantly enhanced. In addition, acteoside, a major constituent of CTE, was found to enhance the mRNA expressions of apolipoprotein B, VLDL receptor, and cytochrome P450 SCC in HepG2 hepatocytes. These results suggest that CTE affects the mRNA expressions of molecules related to cholesterol transport and metabolism and exhibits hypocholesterolemic activity in diet-induced hypercholesterolemia mice. Acteoside was involved in the hypocholesterolemic activity of CTE.
Regulation of Influenza Virus-Caused Oxidative Stress by Kegan Liyan Oral Prescription, as Monitored by Ascorbyl Radical ESR Signals
Authors: Duan Shaojin , Gu Lizhen , Wang Yanyun , Zheng Rongbo , Lu Jingfen , Yin Junjie , Guli Laowa , Ball Michele
Published: November 2009

To study the oxidative stress level of the influenza virus A FM1 subset-infected mouse in intranasal inhalation as a model, we employ an ascorbyl radical's ESR (electron spin resonance) spectrum as an oxidative stress biomarker. These infected mice were pretreated with Ribavirin, ascorbic acid, superoxide dismutase (SOD) or Kegan Liyan oral prescription (KGLY, proprietary Chinese medicine for influenza and common cold) in the stomach tube for 3 days, and then followed by the virus-infecting for 4 days. On the 4th day, samples were collected. It is recognized the strength of ascorbyl radical's ESR signal ( A -.) (a H4 = 0.177 Gauss, g = 2.00517) denotes oxidative stress level in vivo and in vitro. The magnitude of ESR spectrum (28.65 ± 10.71 AU) in mice infected with influenza virus was significantly higher than those of healthy control mice (19.10 ± 3.61 AU). Serum A -. in mice treated with Ribavirin, ascorbic acid, SOD and KGLY declined to 19.70 ± 6.05, 18.50 ± 2.93 and 16.25 ± 3.59, 18.40 ± 2.14 AU respectively. It is close to A -. signal height in healthy controls via down-regulation of the influenza virus-caused oxidative stress level getting decline in the lung index of pneumonia as compare to those of untreated healthy and the influenza virus infected mice pneumonia. It is well known that SOD can prevent the influenza virus pneumonia enhancing mouse survival rate; Ribavirin can treat viral diseases. Data from this study suggested that KGLY may indirectly relieve influenza virus-infected pneumonia via down- regulation of virus caused oxidative stress coupled with a redox reaction cascade as ribavirin, ascorbic acid and SOD.
The Effects and Mechanism of Saponins of Panax notoginseng on Glucose Metabolism in 3T3-L1 Cells
Authors: Kim Jane J.Y. , Xiao Hong , Tan Yi , Wang Zheng-Zhong , Paul Seale J. , Qu Xianqin
Published: November 2009

This study was carried out to determine the effect of saponins of Panax notoginseng (SPN), a naturally occurring cardiovascular agent, on: (1) glucose uptake, (2) GLUT4 translocation and (3) glycogen synthesis in 3T3-L1 adipocytes. Electrospray ionization-Mass spectrometry (ESI-MS) was used to determine the structural characterization of the major active components of SPN. 3T3-L1 adipocytes were cultured and treated with 100 nM insulin alone or with 10, 50 and 100 μg/ml of SPN. [3H]2-deoxyglucose glucose uptake, GLUT4 immunofluorescence imaging and glycogen synthesis assay were carried out to determine the effects of SPN on glucose metabolism. Under insulin stimulation, SPN significantly increased glucose uptake in a dose-dependent manner; 50 μg/ml of SPN increased glucose uptake by 64% (p < 0.001). Immunofluorescence imaging and analysis have revealed that 50 and 100 μg/ml of SPN increased GLUT4 in the plasma membrane by 3-fold and 6-fold respectively (p < 0.001). Furthermore, the incorporation of D-[U-14C] glucose into glycogen was enhanced by 53% in 3T3-L1 cells treated with 100 μg/ml of SPN (p < 0.01 vs. insulin stimulation alone). SPN, a naturally occurring agent used to treat ischemic cardio-cerebral vascular disease in China, enhanced insulin-stimulated glucose uptake and glycogen synthesis in adipocytes. The results of this study indicate that SPN may have a therapeutic potential for hyperglycaemia in type 2 diabetes.
Assessing the Process of Knowledge Transfer — An Empirical Study
Authors: Liyanage Champika , Ballal Tabarak , Elhag Taha
Published: November 2009

This paper investigates and evaluates the process of knowledge transfer in construction projects. Due to the highly competitive nature of business environments, knowledge transfer between organisations has become increasingly popular in recent years. However, although organisations can realise remarkable benefits by transferring knowledge from one unit to another, successful knowledge transfer can be difficult to achieve. The discussions presented in the paper are mainly based on findings of two case studies. The two cases were selected from Private Finance Initiative (PFI) projects in the UK. According to the case study findings, different stages of a knowledge transfer process can be overlapped, omitted, repeated as well as intermitted and then restarted. One of the significant findings of the case studies was the role of the "knowledge mediator". In selected case studies, there were external consultants and expert staff in the form of knowledge mediators. The importance of their roles was frequently highlighted by the interview participants. They were not only facilitating the close liaison between the knowledge source and the receiver, but also their role was strongly associated with practices of translation and interpretation. This combined role of mediator/translator, therefore, appears to be particularly significant for inter-organisational knowledge transfer in PFI projects.
MEASURING THE BENEFITS OF RIVER QUALITY IMPROVEMENT USING THE CONTINGENT VALUATION METHOD: THE CASE OF THE PING RIVER, CHIANG MAI, THAILAND
Authors: MOHAMMED ESSAM YASSIN
Published: November 2009

Rivers provide us with general life support, water supply, transportation, waste assimilation, and a wide array of recreation and tourism activities. However, due to undervaluation of the functions of rivers and river ecosystems, rivers of the world have been overexploited or degraded. To tackle the problem of undervaluation, this study measures the benefits of Ping River quality improvement using the contingent valuation method (CVM). The study estimates the lower-bound and higher-bound annual benefits gained by the residents of Chiang Mai District from the river quality improvement as 42,453,000 THB (1.25 million USD) and 102,835,317 THB (3 million USD), respectively. Moreover, in an attempt to explain the determinants of willingness to pay (WTP) statements, it was found that both behavioural and attitudinal factors affect WTP positively. The study also found distance decay, where WTP statements decreased with increased distance. And rather interestingly, male respondents tend to pay more than their female counterparts. Two other socioeconomic factors which affected WTP positively and significantly are education, partly because it can lead to a well paying and stable job, and normally raises the awareness of citizens towards environmental conservation, as well as income.
A GENERALIZATION OF ROTH'S THEOREM IN FUNCTION FIELDS
Authors: LIU YU-RU , SPENCER CRAIG V.
Published: November 2009

Let 𝔽q[t] denote the polynomial ring over the finite field 𝔽q, and let [Formula: see text] denote the subset of 𝔽q[t] containing all polynomials of degree strictly less than N. For non-zero elements r1, …, rs of 𝔽q satisfying r1 + ⋯ + rs = 0, let [Formula: see text] denote the maximal cardinality of a set [Formula: see text] which contains no non-trivial solution of r1x1 + ⋯ + rsxs = 0 with xi ∈ A (1 ≤ i ≤ s). We prove that [Formula: see text].
A NOTE ON LEHMER k-TUPLES
Authors: LIU HUANING
Published: November 2009

Let q > 2 be an odd number. For each integer a with 1 ≤ a ≤ q and (a, q) = 1, there exists one and only one [Formula: see text] with [Formula: see text] and [Formula: see text] such that [Formula: see text]. A Lehmer number is defined to be any integer a with [Formula: see text]. Let a = (a1, …, ak+1), b = (b1, …, bk+1) with 0 ≤ bi < ai for i = 1, …, k + 1, (a1 ⋯ ak+1, q) = 1, t = (t1, …, tk) satisfying 0 < t1, …, tk ≤ 1. Define [Formula: see text] The main purpose of this paper is to study the properties of N(a, b, t; q), and give a sharp asymptotic formula, by using the estimate for hyper-Kloosterman sums and properties of trigonometric sums.
GAUSSIAN LAWS ON DRINFELD MODULES
Authors: KUO WENTANG , LIU YU-RU
Published: November 2009

Let A = 𝔽q[T] be the polynomial ring over the finite field 𝔽q, k = 𝔽q(T) the rational function field, and K a finite extension of k. Let ϕ be a Drinfeld A-module over K of rank r. For a place 𝔓 of K of good reduction, write [Formula: see text], where [Formula: see text] is the valuation ring of 𝔓 and [Formula: see text] its maximal ideal. Let P𝔓, ϕ(X) be the characteristic polynomial of the Frobenius automorphism of 𝔽𝔓acting on a Tate module of ϕ. Let χϕ(𝔓) = P𝔓, ϕ(1), and let ν(χϕ(𝔓)) be the number of distinct primes dividing χϕ(𝔓). If ϕ is of rank 2 with [Formula: see text], we prove that there exists a normal distribution for the quantity [Formula: see text] For r ≥ 3, we show that the same result holds under the open image conjecture for Drinfeld modules. We also study the number of distinct prime divisors of the trace of the Frobenius automorphism of 𝔽𝔓acting on a Tate module of ϕ and obtain similar results.
CYCLIC ODD DEGREE BASE CHANGE LIFTING FOR UNITARY GROUPS IN THREE VARIABLES
Authors: CHAN PING-SHUN , FLICKER YUVAL Z.
Published: November 2009

Let F be a number field or a p-adic field of odd residual characteristic. Let E be a quadratic extension of F, and F' an odd degree cyclic field extension of F. We establish a base-change functorial lifting of automorphic (respectively, admissible) representations from the unitary group U (3, E/F) to the unitary group U (3, F' E/F'). As a consequence, we classify, up to certain restrictions, the packets of U (3, F' E/F') which contain irreducible automorphic (respectively, admissible) representations invariant under the action of the Galois group Gal (F' E/E). We also determine the invariance of individual representations. This work is the first study of base change into an algebraic group whose packets are not all singletons, and which does not satisfy the rigidity, or "strong multiplicity one", theorem. Novel phenomena are encountered: e.g. there are invariant packets where not every irreducible automorphic (respectively, admissible) member is Galois-invariant. The restriction that the residual characteristic of the local fields be odd may be removed once the multiplicity one theorem for U(3) is proved to hold unconditionally without restriction on the dyadic places.
SYMMETRIC SQUARE L-FUNCTIONS AND SHAFAREVICH–TATE GROUPS, II
Authors: DUMMIGAN NEIL
Published: November 2009

We re-examine some critical values of symmetric square L-functions for cusp forms of level one. We construct some more of the elements of large prime order in Shafarevich–Tate groups, demanded by the Bloch–Kato conjecture. For this, we use the Galois interpretation of Kurokawa-style congruences between vector-valued Siegel modular forms of genus two (cusp forms and Klingen–Eisenstein series), making further use of a construction due to Urban. We must assume that certain 4-dimensional Galois representations are symplectic. Our calculations with Fourier expansions use the Eholzer–Ibukiyama generalization of the Rankin–Cohen brackets. We also construct some elements of global torsion which should, according to the Bloch–Kato conjecture, contribute a factor to the denominator of the rightmost critical value of the standard L-function of the Siegel cusp form. Then we prove, under certain conditions, that the factor does occur.
Abnormalities in focal adhesion complex formation, regulation, and function in human autosomal recessive polycystic kidney disease epithelial cells
Authors: Israeli Sharon , Amsler Kurt , Zheleznova Nadezhda , Wilson Patricia D.
Published: November 2009

Integrin-associated focal adhesion complex formation and turnover plays an essential role in directing interactions between epithelial cells and the extracellular matrix during organogenesis, leading to appropriate cell spreading, cell-matrix adhesion, and migration. Autosomal recessive polycystic kidney disease (ARPKD) is associated with loss of function of PKHD1-encoded protein fibrocystin-1 and is characterized by cystic dilation of renal collecting tubules (CT) in utero and loss of renal function in patients if they survive the perinatal period. Normal polycystin-1 (PC-1)/focal adhesion complex function is required for control of CT diameter during renal development, and abnormalities in these complexes have been demonstrated in human PC-1 mutant cystic cells. To determine whether loss of fibrocystin-1 was associated with focal adhesion abnormalities, ARPKD cells or normal age-matched human fetal (HF)CT cells in which fibrocystin-1 had been decreased by 85% by small interfering RNA inhibition were compared with normal HFCT. Accelerated attachment and spreading on collagen matrix and decreased motility of fibrocystin-1-deficient cells were associated with longer paxillin-containing focal adhesions, more complex actin-cytoskeletal rearrangements, and increased levels of total β1-integrin, c-Src, and paxillin. Immunoblot analysis of adhesive cells using site-specific phospho-antibodies demonstrated ARPKD-associated loss of activation of focal adhesion kinase (FAK) by phosphorylation at its autophosphorylation site (Y397); accelerated FAK inhibition by phosphorylation at Y407, S843, and S910; as well as increased activation of c-Src at pY418. Paxillin coimmunoprecipitation analyses suggested that fibrocystin-1 was a component of the normal focal adhesion complex and that actin and fibrocystin-1 were lost from ARPKD complexes.
Caveolin gene transfer improves glucose metabolism in diabetic mice
Authors: Otsu Koji , Toya Yoshiyuki , Oshikawa Jin , Kurotani Reiko , Yazawa Takuya , Sato Motohiko , Yokoyama Utako , Umemura Satoshi , Minamisawa Susumu , Okumura Satoshi , Ishikawa Yoshihiro
Published: November 2009

Caveolin, a member of the membrane-anchoring protein family, accumulates various growth receptors in caveolae and inhibits their function. Upregulation of caveolin attenuates cellular proliferation and growth. However, the role of caveolin in regulating insulin signals remains controversial. Here, we demonstrate that caveolin potently enhances insulin receptor (IR) signaling when overexpressed in the liver in vivo. Adenovirus-mediated gene transfer was used to overexpress caveolin specifically in the liver of diabetic obese mice, which were generated with a high-fat diet. Expression of molecules involved in IR signaling, such as IR or Akt, remained unchanged after gene transfer. However, hepatic glycogen synthesis was markedly increased with a decrease in phosphoenolpyruvate carboxykinase protein expression. Insulin sensitivity was increased after caveolin gene transfer as determined by decreased blood glucose levels in response to insulin injection and fasting blood glucose levels. Glucose tolerant test performance was also improved. Similar improvements were obtained in KKA y genetically diabetic mice. Adenovirus-mediated overexpression of caveolin-3 in hepatic cells also enhanced IR signaling, as shown by increased phosphorylation of IR in response to insulin stimulation and higher glycogen synthesis at baseline. These effects were attributed mostly to increased insulin receptor activity and caveolin-mediated, direct inhibition of protein tyrosine phosphatase 1B, which was increased in obese mouse livers. In conclusion, our results suggest that caveolin is an important regulator of glucose metabolism that can enhance insulin signals.
Cytoskeletal structure regulates endothelial cell immunogenicity independent of fluid shear stress
Authors: Vartanian Keri B. , Berny Michelle A. , McCarty Owen J. T. , Hanson Stephen R. , Hinds Monica T.
Published: November 2009

The cardiovascular disease atherosclerosis is directly linked to the functions of endothelial cells (ECs), which are affected by fluid shear stress (FSS). High, unidirectional FSS causes EC elongation with aligned cytoskeletal components and nonimmunogenic EC functions that protect against atherosclerosis. In contrast, low, oscillatory FSS is associated with cobblestone-shaped ECs with randomly oriented cytoskeletons and proinflammatory EC functions that promote atherosclerosis. Whether EC shape plays a role in EC immunogenic functions, independent of FSS, has not been previously determined. The goal of this study was to determine the effect of EC elongation and cytoskeletal alignment on the expression of inflammatory genes and functions. With the use of micropatterned lanes, EC elongation and cytoskeletal alignment were achieved in the absence of FSS. EC gene expression of key inflammation markers determined that the elongation and cytoskeletal alignment of micropattern-elongated ECs (MPECs) alone significantly downregulated VCAM-1 while having no effect on E-selectin and ICAM-1. The positive control of FSS-elongated ECs promoted E-selectin and VCAM-1 downregulation and upregulation of ICAM-1. Functionally, monocytic U937 cells formed weaker interactions on the surface of MPECs compared with cobblestone ECs. Interestingly, MPEC expression of the known FSS-dependent transcription factor krüppel-like factor 2 (KLF2), which promotes a nonimmunogenic EC phenotype, was significantly upregulated in MPECs compared with cobblestone ECs. Cytoskeletal regulation of KLF2 expression was shown to be dependent on microtubules. Therefore, the cellular elongation and cytoskeletal alignment of MPECs regulated immunogenic gene expression and functions and may act synergistically with FSS to create an EC surface with reduced inflammatory capability.
Phosphatidylinositol 4,5-bisphosphate and loss of PLCγ activity inhibit TRPM channels required for oscillatory Ca2+ signaling
Authors: Xing Juan , Strange Kevin
Published: November 2009

The Caenorhabditis elegans intestinal epithelium generates rhythmic inositol 1,4,5-trisphosphate (IP3)-dependent Ca2+ oscillations that control muscle contractions required for defecation. Two highly Ca2+-selective transient receptor potential (TRP) melastatin (TRPM) channels, GON-2 and GTL-1, function with PLCγ in a common signaling pathway that regulates IP3-dependent intracellular Ca2+ release. A second PLC, PLCβ, is also required for IP3-dependent Ca2+ oscillations, but functions in an independent signaling mechanism. PLCγ generates IP3 that regulates IP3 receptor activity. We demonstrate here that PLCγ via hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) also regulates GON-2/GTL-1 function. Knockdown of PLCγ but not PLCβ activity by RNA interference (RNAi) inhibits channel activity ∼80%. Inhibition is fully reversed by agents that deplete PIP2 levels. PIP2 added to the patch pipette has no effect on channel activity in PLCγ RNAi cells. However, in control cells, 10 μM PIP2 inhibits whole cell current ∼80%. Channel inhibition by phospholipids is selective for PIP2 with an IC50 value of 2.6 μM. Elevated PIP2 levels have no effect on channel voltage and Ca2+ sensitivity and likely inhibit by reducing channel open probability, single-channel conductance, and/or trafficking. We conclude that hydrolysis of PIP2 by PLCγ functions in the activation of both the IP3 receptor and GON-2/GTL-1 channels. GON-2/GTL-1 functions as the major intestinal cell Ca2+ influx pathway. Calcium influx through the channel feedback regulates its activity and likely functions to modulate IP3 receptor function. PIP2-dependent regulation of GON-2/GTL-1 may provide a mechanism to coordinate plasma membrane Ca2+ influx with PLCγ and IP3 receptor activity as well as intracellular Ca2+ store depletion.
Molecular determinants dictating cell surface expression of the human sodium-dependent vitamin C transporter-2 in human liver cells
Authors: Subramanian Veedamali S. , Marchant Jonathan S. , Said Hamid M.
Published: November 2009

The human sodium-dependent vitamin C transporter-2 (hSVCT2) plays an important role in cellular accumulation of ascorbic acid in liver cells. However, little is known about the molecular determinants that direct hSVCT2 to the cell surface in hepatocytes. We addressed this issue using live cell imaging methods to resolve the distribution and trafficking of truncated or mutated hSVCT2 constructs in a cellular model of human hepatocytes, HepG2 cells. Whereas a full-length hSVCT2-yellow fluorescent protein (YFP) fusion protein was functionally expressed at the cell surface in HepG2 cells, serial truncation and mutation analysis demonstrated an essential role for both NH2- and COOH-terminal sequence(s) for cell surface expression and function. Video-rate confocal imaging showed evidence of dynamic hSVCT2-YFP containing intracellular trafficking vesicles, the motility of which was impaired following disruption of microtubules using nocodazole. However, in a HepG2 cell line stably expressing hSVCT2-YFP at the cell surface, plasma membrane levels of hSVCT2 were unaffected by inhibition of microtubule-associated motor proteins; rather, surface expression of hSVCT2-YFP was increased following treatment with myosin inhibitors. Together, these results show that 1) both NH2- and COOH-terminal sequences are essential for proper localization of hSVCT2, 2) cell surface delivery is dependent on intact microtubules, and 3) peripheral microfilaments regulate insertion and retrieval of hSVCT2 into the plasma membrane.
Fetal adrenal gland alterations in a rat model of adverse intrauterine environment
Authors: Bibeau Karine , Battista Marie-Claude , Houde Véronique , Brochu Michèle
Published: November 2009

By feeding a low-sodium diet to dams over the last third of gestation, we have developed an animal model of intrauterine growth restriction (IUGR). Given that fetal adrenal development and maturation occur during late gestation in rats, the aim of this study was to evaluate the expression of proteins and enzymes involved in steroidogenesis and catecholamine synthesis in adrenal glands from IUGR fetuses. A gene microarray was performed to investigate for alteration in the pathways participating in hormone production. Results show that increased aldosterone serum concentrations in IUGR fetuses were associated with higher mRNA adrenal levels of angiotensin II receptor type 1 (AT1R) and cytochrome P450 aldosterone synthase in response to decreased serum sodium content. Conversely, reduced serum corticosterone concentrations in these fetuses appear to result from alterations in gene expression involved in cholesterol metabolism, such as the augmented apolipoprotein E levels, and in steroidogenesis, like the decreased levels of cytochrome P45011β-hydroxylase. Furthermore, increased AT2R expression and the presence of hypoxia and oxidative stress may, in turn, explain the higher adrenal mRNA levels of enzymes involved in catecholamine synthesis. Despite this increase, catecholamine adrenal content was reduced in males and was similar in females compared with sex-matched controls, suggesting higher catecholamine secretion. This could be associated with the induction of genes involved in inflammation-related, acute-phase response in IUGR fetuses. All of these alterations could have long-lasting health effects and may, hence, be implicated in the pathogenesis of increased blood pressure and cardiac hypertrophy observed in IUGR adult animals from this model.
Magnetic resonance imaging of hypoxic injury to the murine placenta
Authors: Tomlinson Tracy M. , Garbow Joel R. , Anderson Jeff R. , Engelbach John A. , Nelson D. Michael , Sadovsky Yoel
Published: November 2009

We assessed the use of magnetic resonance imaging (MRI) to define placental hypoxic injury associated with fetal growth restriction. On embryonic day 18.5 (E18.5) we utilized dynamic contrast-enhanced (DCE)-MRI on a 4.7-tesla small animal scanner to examine the uptake and distribution of gadolinium-based contrast agent. Quantitative DCE parameter analysis was performed for the placenta and fetal kidneys of three groups of pregnant C57BL/6 mice: 1) mice that were exposed to FiO2= 12% between E15.5 and E18.5, 2) mice in normoxia with food restriction similar to the intake of hypoxic mice between E15.5 and E18.5, and 3) mice in normoxia that were fed ad libitum. After imaging, we assessed fetoplacental weight, placental histology, and gene expression. We found that dams exposed to hypoxia exhibited fetal growth restriction (weight reduction by 28% and 14%, respectively, P < 0.05) with an increased placental-to-fetal ratio. By using MRI-based assessment of placental contrast agent kinetics, referenced to maternal paraspinous muscle, we found decreased placental clearance of contrast media in hypoxic mice, compared with either control group (61%, P < 0.05). This was accompanied by diminished contrast accumulation in the hypoxic fetal kidneys (23%, P < 0.05), reflecting reduced transplacental gadolinium transport. These changes were associated with increased expression of placental Phlda2 and Gcm1 transcripts. Exposure to hypoxia near the end of mouse pregnancy reduces placental perfusion and clearance of contrast. MRI-based DCE imaging provides a novel tool for dynamic, in vivo assessment of placental function.
BK channel activation by NS11021 decreases excitability and contractility of urinary bladder smooth muscle
Authors: Layne Jeffrey J. , Nausch Bernhard , Olesen Søren-Peter , Nelson Mark T.
Published: November 2009

Large-conductance Ca2+-activated potassium (BK) channels play an important role in regulating the function and activity of urinary bladder smooth muscle (UBSM), and the loss of BK channel function has been shown to increase UBSM excitability and contractility. However, it is not known whether activation of BK channels has the converse effect of reducing UBSM excitability and contractility. Here, we have sought to investigate this possibility by using the novel BK channel opener NS11021. NS11021 (3 μM) caused an approximately threefold increase in both single BK channel open probability ( Po) and whole cell BK channel currents. The frequency of spontaneous action potentials in UBSM strips was reduced by NS11021 from a control value of 20.9 ± 5.9 to 10.9 ± 3.7 per minute. NS11021 also reduced the force of UBSM spontaneous phasic contractions by ∼50%, and this force reduction was blocked by pretreatment with the BK channel blocker iberiotoxin. NS11021 (3 μM) had no effect on contractions evoked by nerve stimulation. These findings indicate that activating BK channels reduces the force of UBSM spontaneous phasic contractions, principally through decreasing the frequency of spontaneous action potentials.
Dorsomedial hypothalamus mediates autonomic, neuroendocrine, and locomotor responses evoked from the medial preoptic area
Authors: Hunt Joseph L. , Zaretsky Dmitry V. , Sarkar Sumit , DiMicco Joseph A.
Published: November 2009

Previous studies suggest that sympathetic responses evoked from the preoptic area in anesthetized rats require activation of neurons in the dorsomedial hypothalamus. Disinhibition of neurons in the dorsomedial hypothalamus in conscious rats produces physiological and behavioral changes resembling those evoked by microinjection of muscimol, a GABAA receptor agonist and neuronal inhibitor, into the medial preoptic area. We tested the hypothesis that all of these effects evoked from the medial preoptic area are mediated through neurons in the dorsomedial hypothalamus by assessing the effect of bilateral microinjection of muscimol into the DMH on these changes. After injection of vehicle into the dorsomedial hypothalamus, injection of muscimol into the medial preoptic area elicited marked increases in heart rate, arterial pressure, body temperature, plasma ACTH, and locomotor activity and also increased c-Fos expression in the hypothalamic paraventricular nucleus, a region known to control the release of ACTH from the adenohypophysis. Prior bilateral microinjection of muscimol into the dorsomedial hypothalamus produced a modest depression of baseline heart rate and body temperature but completely abolished all changes evoked from the medial preoptic area. Microinjection of muscimol just anterior to the dorsomedial hypothalamus had no effect on autonomic and neuroendocrine changes evoked from the medial preoptic area. Thus, activity of neurons in the dorsomedial hypothalamus mediates a diverse array of physiological and behavioral responses elicited from the medial preoptic area, suggesting that the latter region represents an important source of inhibitory tone to key neurons in the dorsomedial hypothalamus.
Melanocortin activity in the amygdala controls appetite for dietary fat
Authors: Boghossian Stéphane , Park MieJung , York David A.
Published: November 2009

The amygdala is rich in melanocortin 4 receptors. Because the reduction in dietary fat intake after enterostatin is injected in the central nucleus of the amygdala (CeA) is blocked by a melanocortin 4 receptor antagonist, we investigated the role of melanocortin activity in the CeA in regulating food intake and macronutrient choice. Sprague-Dawley rats, fitted with CeA cannulas, were fed either chow, a high-fat (HF) diet, or adapted to a two-choice HF or low-fat (LF) diet. Injections of the MC4R agonist melanotan II (MTII) in the CeA had a dose-dependent inhibitory effect on food intake that lasted for at least 24 h. This response was greater in rats fed a HF diet. The inverse agonist agouti-related protein (AgRP) and antagonist SHU-9119 increased food intake in a dose-dependent manner, with the hyperphagia lasting for 60 h. In rats adapted to a two-choice HF/LF diet, MTII decreased HF consumption but had no effect on LF consumption, resulting in a long-lasting decrease in total calorie intake (−35.5% after 24 h, P < 0.05). Total calorie intake increased in both AgRP- and SHU-9119-treated rats (32 and 109% after 24 h, respectively) as the result of increased intake of HF diet. There was no modification of LF consumption with AgRP treatment and a transient nonsignificant decrease with SHU-9119 treatment. Amygdala brain-derived neurotrophic factor expression was increased by AgRP in fed rats. These results identify the amygdala as a site of action for the melanocortin system to control food intake and dietary preferences.
The cardiovascular and endocrine responses to voluntary and forced diving in trained and untrained rats
Authors: McCulloch Paul F. , DiNovo Karyn. M. , Connolly Tiffanny M.
Published: November 2009

The mammalian diving response, consisting of apnea, bradycardia, and increased total peripheral resistance, can be modified by conscious awareness, fear, and anticipation. We wondered whether swim and dive training in rats would 1) affect the magnitude of the cardiovascular responses during voluntary and forced diving, and 2) whether this training would reduce or eliminate any stress due to diving. Results indicate Sprague-Dawley rats have a substantial diving response. Immediately upon submersion, heart rate (HR) decreased by 78%, from 453 ± 12 to 101 ± 8 beats per minute (bpm), and mean arterial pressure (MAP) decreased 25%, from 143 ± 1 to 107 ± 5 mmHg. Approximately 4.5 s after submergence, MAP had increased to a maximum 174 ± 3 mmHg. Blood corticosterone levels indicate trained rats find diving no more stressful than being held by a human, while untrained rats find swimming and diving very stressful. Forced diving is stressful to both trained and untrained rats. The magnitude of bradycardia was similar during both voluntary and forced diving, while the increase in MAP was greater during forced diving. The diving response of laboratory rats, therefore, appears to be dissimilar from that of other animals, as most birds and mammals show intensification of diving bradycardia during forced diving compared with voluntary diving. Rats may exhibit an accentuated antagonism between the parasympathetic and sympathetic branches of the autonomic nervous system, such that in the autonomic control of HR, parasympathetic activity overpowers sympathetic activity. Additionally, laboratory rats may lack the ability to modify the degree of parasympathetic outflow to the heart during an intense cardiorespiratory response (i.e., the diving response).
The opioid growth factor-opioid growth factor receptor axis regulates cell proliferation of human hepatocellular cancer
Authors: Avella Diego M. , Kimchi Eric T. , Donahue Renee N. , Tagaram Hephzibah Rani S. , McLaughlin Patricia J. , Zagon Ian S. , Staveley-O'Carroll Kevin F.
Published: November 2009

Hepatocellular carcinoma (HCC) is the third leading cause of cancer deaths worldwide, with a mortality rate approximating its incidence. Understanding the biology of these tumors, as well as treatment modalities, has been challenging. The opioid growth factor (OGF; [Met5]-enkephalin) and the OGF receptor (OGFr) form an endogenous growth-regulating pathway in homeostasis and neoplasia. In this investigation, we examined the relationship of the OGF-OGFr axis in HCC and define its presence, function, and mechanism. Using SK-HEP-1, Hep G2, and Hep 3B human HCC cell lines, we found that OGF and OGFr were present and functional. Exogenous OGF was observed to have a dose-dependent, reversible, and receptor-mediated inhibitory action on cell proliferation. Endogenous OGF was found to be constitutively produced and tonically active on cell replicative activities, with neutralization of this peptide accelerating cell proliferation. Silencing of OGFr using siRNA stimulated cell replication, even when exogenous OGF was added to the cultures, documenting its importance in mediating OGF activity. The mechanism of OGF-OGFr action on cell number was related to inhibition of DNA synthesis and not to apoptotic or necrotic pathways. Both OGF and OGFr were detected in surgical specimens of HCC, and no quantitative differences were recorded in peptide or receptor between pathological and normal specimens. These data are the first to report that the OGF-OGFr system is a native biological regulator of cell proliferation in HCC. The findings may provide important insight in designing treatment strategies for this deadly disease.
Nitric oxide originating from NOS1 controls oxygen utilization and electrolyte transport efficiency in the diabetic kidney
Authors: Palm Fredrik , Fasching Angelica , Hansell Peter , Källskog Örjan
Published: November 2009

Nitric oxide (NO) is a potent regulator of both vascular tone and cellular oxygen consumption (Qo2). Diabetic kidneys have reduced NO availability and increased Qo2. However, the exact nitric oxide synthase (NOS) isoform regulating Qo2, hemodynamics, and excretory function in the diabetic kidney remains unclear. We therefore investigated the effects of both selective neuronal NOS (NOS1) inhibition and nonselective NOS inhibition. Oxygen utilization, electrolyte transport efficiency [tubular Na+transport (TNa)/Qo2], renal blood flow (RBF), glomerular filtration rate (GFR), and mean arterial pressure (MAP) were measured in vivo in control and streptozotocin-diabetic rats before and after administration of the selective NOS1 inhibitor S-methyl-l-thiocitrulline (SMTC) or the nonselective NOS inhibitor NG-nitro-l-arginine methyl ester (l-NAME). Diabetic rats had higher baseline Qo2and GFR than control rats, although RBF was similar in the groups. SMTC and l-NAME increased Qo2and reduced TNa/Qo2only in the diabetic animals, whereas both inhibitors increased MAP and reduced RBF in both groups. GFR was reduced by l-NAME, but SMTC had no effect in either group. Carbachol increased RBF and decreased MAP in SMTC-treated rats, whereas it had no effect in l-NAME-treated rats, indicating that SMTC selectively inhibited NOS1. In conclusion, NO regulates RBF and GFR similarly in both control and diabetic rats. However, selective NOS1 inhibition increased Qo2and reduced TNa/Qo2in the diabetic rat kidney, indicating a pivotal role of NO produced by NOS1 in maintaining control of Qo2and tissue oxygenation in these kidneys.
A mathematical model of rat ascending Henle limb. I. Cotransporter function
Authors: Weinstein Alan M.
Published: November 2009

Kinetic models of Na+-K+-2Cl−costransporter (NKCC2) and K+-Cl−cotransporter (KCC4), two of the key cotransporters of the Henle limb, are fashioned with inclusion of terms representing binding and transport of NH4+. The models are simplified using assumptions of equilibrium ion binding, binding symmetry, and identity of Cl−binding sites. Model parameters are selected to be consistent with flux data from expression of these transporters in oocytes, specifically inwardly directed coupled transport of rubidium. In the analysis of these models, it is found that despite the simplifying assumptions to reduce the number of model parameters, neither model is uniquely determined by the data. For NKCC or KCC there are two- or three-parameter families of “optimal” solutions. As a consequence, one may specify several carrier translocation rates and/or ion affinities before fitting the remaining coefficients to the data, with no loss of fidelity in simulating the experiments. Model calculations suggest that with respect to NKCC2 near its operating point, the curve of ion flux as a function of cell Cl−is steep, and with respect to KCC4, its curve of ion flux as a function of peritubular K+is also steep. The implication is that the kinetics are suitable for these two transporters in series to act as a sensor for peritubular K+, to modulate AHL Na+reabsorption, with cytosolic Cl−as the intermediate variable. The models also reveal the potential for luminal NH4+to be a potent catalyst for NKCC2 Na+reabsorption, provided suitable exit mechanisms for NH4+(from cell-to-lumen) are operative. It is found that KCC4 is likely to augment the secretory NH4+flux, with peritubular NH4+uptake driven by the cell-to-blood K+gradient.
Heterogeneity of H-K-ATPase-mediated acid secretion along the mouse collecting duct
Authors: Lynch I. Jeanette , Greenlee Megan M. , Gumz Michelle L. , Rudin Alicia , Xia Shen-Ling , Wingo Charles S.
Published: November 2009

In the collecting duct (CD), H-K-ATPases function in cation reabsorption and H secretion. This study evaluated H-K-ATPase-mediated H secretion along the mouse CD, measured as EIPA- and luminal bafilomycin A1-insensitive intracellular pH (pHi) recovery from acute H loading (NH4) using BCECF. pHirecovery was measured in 1) microperfused cortical, outer medullary, and inner medullary CDs (CCD, OMCD, and IMCD) from C57BL/6J mice fed a normal diet and 2) common murine CD cell lines. H-K-ATPase activity along the native, microperfused CD was greatest in the CCD, less in the OMCD, and least in the IMCD (0.10 ± 0.02, 0.04 ± 0.01, and 0.01 ± 0.002 U/min, respectively). H-K-ATPase activity was 0.30 ± 0.03 and 0.26 ± 0.03 in A- and B-type ICs, respectively, and was sensitive to Sch-28080 or ouabain. pHirecovery was greatest in the OMCD1cell line (0.25 ± 0.01) and less in mpkCCDc14(0.17 ± 0.01), mIMCD-K2 (0.12 ± 0.01), and mIMCD-3 (0.05 ± 0.01) cells. EIPA inhibited the majority of pHirecovery in these cells (100%, 64%, 75%, and 80% in mpkCCDc14, OMCD1, mIMCD-K2, and mIMCD-3, respectively). In OMCD1cells, where EIPA-insensitive pHirecovery was greatest, H-K-ATPase activity was 0.10 ± 0.01 and was significantly inhibited (80%) by Sch-28080. We conclude that 1) H-K-ATPase-mediated H secretion in the native mouse CD is greatest in the ICs of the CCD, 2) A- and B-type ICs possess HKα1and HKα2H-K-ATPase activity, and 3) the OMCD1cell line best exhibits H-K-ATPase.