bluuebunny/crossref_metadata_2025 huggingface dataset:
Prognostic value of insulinlike growth factor I and its binding protein in patients with alcohol-induced liver disease
Authors: Moller S , Becker U , Juul A , Skakkebaek N E , Christensen E
Published: November 2004

Insulinlike growth factor I (IGF-I) is a single-polypeptide chain with important anabolic and endocrine activities. The liver is the major source of IGF-I and its binding protein, IGFBP-3. Circulating concentrations of IGF-I and IGFBP-3 are decreased in patients with chronic liver disease and correlate with the severity. The aim of this study was to assess the additional prognostic value of IGF-I and IGFBP-3 in patients entered in a large multicenter study (EMALD). Three hundred thirty-seven patients with alcohol-induced liver disease were studied in a randomized placebo-controlled trial of malotilate with a mean follow-up period of 569 days (range, 7-1,544). A multivariate Cox regression analysis of pertinent clinical and biochemical variables showed a significant independent prognostic value of years of alcohol intake, coagulation factors 2, 7, and 10, alkaline phosphatases, serum creatinine, and immunoglobulin (Ig) M. When IGF-I or IGFBP-3 were added into this model, a Cox regression analysis showed that either had a significant independent prognostic value. Because IGF-I and IGFBP-3 were closely correlated, they contained almost the same prognostic information. Inclusion of IGF-I gave these results: IGF-I (P < .03), alcohol intake (P < .02), coagulation factors 2, 7, and 10 (P < .01), creatinine (P < .001), and IgM (P < .01) contained independent prognostic information. Inclusion of IGFBP-3 gave these results: IGFBP-3 (P < .02), alcohol intake (P < .05), coagulation factors 2, 7, 10 (P < .01), creatinine (P < .001), and IgM (P < .02) were independent predictors of survival. In conclusion, IGF-I or IGFBP-3 provide important additional information on survival in patients with alcohol-induced liver disease.
Detection of a unique γ-glutamyl transpeptidase messenger RNA species closely related to the development of hepatocellular carcinoma in humans: A new candidate for early diagnosis of hepatocellular carcinoma
Authors: Tsutsumi M , Sakamuro D , Takada A , Zang S , Furukawa T , Taniguchi N
Published: November 2004

Many studies concerning γ-glutamyl transpeptidase (GGTP) in hepatocellular carcinoma (HCC) have suggested that changes in hepatic GGTP expression may be closely related to the development of HCC. However, its mechanisms are not well known, and genomic analysis of the specific GGTP to HCC is also lacking. Recently, the human GGTP complementary DNA (cDNA) sequences from fetal liver, placenta, and HepG2 cells have been published. In the present study, we sought to clarify the distribution of the GGTP messenger RNA (mRNA) molecular species in human liver and determine whether alterations in GGTP mRNA expression occur upon the development of HCC. The specific primer sets for reverse-transcription polymerase chain reaction (PCR) corresponding to the 5′-noncoding human GGTP mRNA of fetal liver (type A), HepG2 cells (type B), and placenta (type C) were prepared. Oligonucleotide probes specific for each type of mRNA were also synthesized. Liver tissues were obtained from patients with or without HCC, and total RNA was extracted. Total RNA was also extracted from various organs obtained from one male patient upon autopsy. Types of GGTP mRNAs were analyzed using type-specific primer sets and oligonucleotide probes. The types of GGTP mRNA varied in different organs. In normal liver and diseased liver without HCC, the main type of GGTP mRNA was type A. The expression was monogenic in most cases but was polygenic in some cases. In the polygenic cases, type C was common, but type B was found occasionally. On the other hand, type B was predominant in cancerous tissues with HCC. In noncancerous tissues of livers with HCC, the main types were types A and B. The prevalence of type B was significantly higher in both cancerous and noncancerous tissues of livers with HCC than in livers without HCC. The prevalence of type A in cancerous tissue, but not in noncancerous tissue, was significantly lower than in livers without HCC. These results strongly suggested that the GGTP mRNA expression in human liver may shift from type A to type B during the development of HCC. The high prevalence of type B in noncancerous tissues suggested that the shift of the GGTP mRNA may occur from the preneoplastic stage of hepatocytes.
Reversible impairment of neonatal hepatobiliary function by maternal cholestasis
Authors: Monte M J , Morales A I , Arevalo M , Alvaro I , Macias R I , Marin J J
Published: November 2004

The effect of total blockage of maternal biliary excretion during the last third of the pregnancy on the maturation of hepatobiliary function was investigated in neonatal rats. Extrahepatic obstruction of the common bile duct on day 14 of pregnancy induced a marked enhancement in serum bilirubin-mainly conjugated bilirubin-and bile acid concentrations as compared with sham-operated pregnant rats. Excretion of bile acids by the kidney was significantly increased, whereas fecal elimination of these compounds was almost abolished. Most of the cholestatic mothers (CMs) (77%) were able to carry pregnancy to term and lactation until weaning (21 days after birth). The body and liver weights of their offspring were lower than for offspring of control healthy mothers in all postnatal periods considered. Serum bile acid concentrations were higher in the fetuses and neonates of CMs. This difference was evident up to 1 week after weaning and disappeared in young adult animals (8 weeks old). When the bile secretion rate was investigated in these animals at 4 or 8 weeks of age, no significant difference was found as far as nonstimulated bile flow and bile acid output was concerned. However, the biliary response to stepwise sodium taurocholate (TC) intravenous infusion showed that 4-week-old neonates of CMs had impaired bile acid secretion. Moreover, the maximal secretion rate (SRmax) for TC was significantly reduced (-30%), whereas the choleretic ability of taurocholate was not modified. This alteration was not selective for bile acids. The SRmax for bromosulfophthalein (BSP) was also significantly lowered (-40%). These dysfunctions were overcome during subsequent development. No impaired biliary response to either TC or BSP infusion was observed at 8 weeks of age. Morphological abnormalities in the canaliculi were found in animals with impaired biliary function. In summary, these results indicate that maternal cholestasis may profoundly but transiently impair the normal liver maturation. The importance of the implications derived from these findings both in the nutrition and management of human neonates demands further evaluation of the hepatobiliary function of babies born after alterations of fetal-maternal bile acid homeostasis, such as in maternal obstetric cholestasis.
Binding of apolipoprotein A-I and acetaldehyde-modified apolipoprotein A-I to liver extracellular matrix
Authors: Paradis V , Mathurin P , Ratziu V , Poynard T , Bedossa P
Published: November 2004

Apolipoprotein A-I (Apo A-I), a protein produced mainly by hepatocytes, is decreased in the sera of alcoholic patients with liver fibrosis and cirrhosis. To explain this decrease, we investigated possible interactions between liver extracellular matrix (ECM) and Apo A-I. Using a solid-phase binding assay, we evaluated the binding of Apo A-I to the different liver matrix components. Apo A-I bound significantly to fibronectin (FN) (optical density [OD] = 1.11 ± .26, P = .01) and collagen (C) I (OD = 0.91 ± 0.22, P = .02) in comparison with bovine serum albumin (BSA) (OD = 0.26 ± 0.16). Binding of Apo A-I to fibronectin was concentration dependent and saturable. Apo A-I bound also to ECM in vivo because Apo A-I was detected by immunofluorescence on fibrous septa in liver biopsy specimens of alcoholic patients. Because a negative correlation between Apo A-I and liver fibrosis is amplified in alcoholic patients, we investigated whether the in vitro formation of Apo A-I/acetaldehyde complex (adducts) increased the binding of Apo A-I to the ECM. We showed that the amount of Apo A-I that bound to FN was significantly higher with acetaldehyde-modified Apo A-I (OD = 2.18 ± 0.19, P = .01) than with native Apo A-I. This increase was probably related to the formation and binding of Apo A-I dimers, because immunoblot of in vitro acetaldehyde-modified Apo A-I showed the formation of dimeric Apo A-I. In conclusion, FN binds both native and acetaldehyde-modified Apo A-I. Because FN is deposited early and in excess during liver fibrosis, a storage mechanism of Apo A-I on newly deposited fibronectin would explain, in part, the decrease observed in alcoholic patients with liver fibrosis.
Hepatitis B Virus Infection of Tupaia Hepatocytes In Vitro And In Vivo
Authors: Walter E , Keist R , Niederöst B , Pult I , Blum H E
Published: November 2004

For the systematic analysis of various clinical and molecular aspects of hepatitis B virus (HBV) infection, an experimental small animal system of HBV infection would be a great advance. The susceptibility to HBV infection, therefore, of hepatocytes from the tree shrew species tupaia belangeri was studied

in vitro

and

in vivo

. Primary hepatocytes isolated from livers of tupaias can be reproducibly infected with HBV.

In vitro

infection results in viral DNA and RNA synthesis in hepatocytes and secretion hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) into culture medium. Tupaias can also be infected with HBV

in vivo

, resulting in viral DNA replication and gene expression in tupaia livers. Similar to acute, self–limited hepatitis B in humans HBsAg is rapidly cleared from serum, followed by seroconversion to anti–HBe and anti–HBs. These data clearly tht HBV is infectious to tupaia hepatocytes

in vitro

and transiently

in vivo

. Tupaias, therefore, may become a useful model for the experimental analysis of various molecular and clinical aspects of HBV infection, including the significance of HBV quasispecies, the steps involved in hepatocarcinogenesis as well as the evaluation of various antiviral strategies.
Prolonged Fecal Excretion of Hepatitis A Virus in Adult Patients With Hepatitis A As Determined by Polymerase Chain Reaction
Authors: Yotsuyanagi H , Koike K , Yasuda K , Moriya K , Shintani Y , Fujie H , Kurokawa K , Iino S
Published: November 2004

In hepatitis A virus (HAV) infection, fecal excretion of the virus has been reported to cease shortly after symptoms occur. Although there have been several reports on detection of HAV in feces using polymerase chain reaction (PCR), the duration of fecal HAV shedding in human adult hepatitis A has not been well described. In the present study, we applied the reverse–transcription (RT)–PCR system to the detection of fecal HAV RNA in 10 patients with sporadic hepatitis A. The viral genomic RNA was detected in the stools from five patients after the onset of clinical symptoms. All stool samples collected within 10 days of onset of illness were HAV–RNA–positive, and the duration of positivity lasted from a few days to as long as 3 months. In four patients, HAV RNA was detected in the stool even after the serum alanine transaminase (ALT) levels had peaked, and in one patient well after ALT levels fell to normal. These results show that fecal shedding of HAV can last for months after resolution of symptoms and such patients could be a source of further spreading of the virus in the community.
Expression and Immune Response to Hepatitis C Virus Core Dna-Based Vaccine Constructs
Authors: Tokushige K , Wakita T , Pachuk C , Moradpour D , Weiner D B , Zurawski V R , Wands J R
Published: November 2004

Hepatitis C virus (HCV) is a major worldwide cause of acute and chronic hepatitis, cirrhosis, and hepatocellular carcinoma. The development of vaccines against HCV have been complicated by the high variability of the envelope region, and it is likely that the cellular immune responses to viral structural proteins may be important for eradicating persistent viral infection. Recently, it was reported that the injection into muscle cells of plasmids encoding viral genes resulted in the generation of strong cellular immune responses. We constructed vectors that express the highly conserved HCV core gene. In this regard, the pHCV 2–2 construct contained the entire HCV core region and pHCV 4–2 contained both the 5′ noncoding region and the core gene. Cellular expression of HCV core protein was assessed following transfection into human and murine cell lines, and higher intracellular levels of the 21–kd core protein were observed with pHCV 2–2. These HCV core DNA constructs were used to immunize BALB/c mice and produced low–level anti–HCV core humoral immune responses. To assess cytotoxic T–lymphocyte (CTL) activity generated

in vivo

, a cloned syngeneic SP2/O myeloma cell line constitutively expressing HCV core protein was established and inoculated into BALB/c mice to produce growth of plasmacytomas. Strong CTL activity was generated because the tumor size and weight in pHCV 2–2–immunized mice were remarkably reduced compared with mice injected with mock DNA. Spontaneous CTL activity was also exhibited by splenocytes in an in vitro cytotoxicity assay. These investigations demonstrate that plasmid constructs expressing HCV core protein generate strong CTL activity, as assessed both

in vivo

and

in vitro

, and are promising candidates as antiviral agents.
Albumin But Not Fibrinogen Synthesis Correlates With Galactose Elimination Capacity in Patients With Cirrhosis of the Liver
Authors: Ballmer P E , Reichen J , McNurlan M A , Sterchi A B , Anderson S E , Garlick P J
Published: November 2004

Albumin and fibrinogen synthesis rates were measured in 15 subjects with different clinical stages of postviral cirrhosis and compared with galactose elimination capacity and aminopyrin breath test. Forty–three mg per kg body weight [2H5ring]phenylalanine with an isotopic enrichment of 10 atom% were intravenously injected. [2H5ring]phenylalanine enrichments in the plasma–free phenylalanine and the albumin and fibrinogen isolates were measured by gas chromatography–mass spectrometry. Fractional synthesis rates of albumin were normal in Child A cirrhosis (7.6 ± 2.2%d), but were lower in both Child B (3.5 ± 0.8%d) and C (4.5 ± 2.8%d). Absolute rates of albumin synthesis were (103 ± 30 mg/kg/d) in the child A group and substantially lower in the Child B (50 ± 3 mg/kg/d) and C (36 ± 20 mg/kg/d) group. The average fractional synthesis rate of fibrinogen was 16.7 ± 7.5%d and the absolute synthesis rate 11.6 ± 6.4 mg/kg/d. The values of the galactose elimination capacity and the aminopyrin breath test were below the normal range in all patients, gradually decreasing with an increase in the severity of the clinical stage of cirrhosis. Albumin synthesis rates significantly correlated with the Child scores, the galactose elimination capacity, and the aminopyrin breath test, whereas fibrinogen synthesis rates showed no such correlations.
Noninvasive Assessment of Hepatic Triglyceride Content in Humans With 13C Nuclear Magnetic Resonance Spectroscopy
Authors: Petersen K F , West A B , Reuben A , Rothman D L , Shulman G I
Published: November 2004

Hepatic lipid content was assessed noninvasively in 15 patients with hepatic steatosis by 13C nuclear magnetic resonance (NMR) spectroscopy, and compared in a double–blind fashion with histological grading and morphometric quantitation of fat in liver biopsies taken within 2 weeks of the study. The lipid content in the liver biopsies was expressed as the volume fraction of total parenchyma occupied by fat. Hepatic triglyceride content was determined by comparing the 13C NMR signal intensity in vivo with the signal intensity obtained from a lipid phantom of known concentrations. There was an approximately 30–fold increase in the 13C NMR signals of the saturated carbons (methyl/methylene [CH2]n) region of hepatic triglycerides from patients with grade 4 steatosis compared with those with grade 0, yielding a good dynamic range for measuring hepatic triglyceride content. The correlation coefficient between the morphometric and 13C NMR techniques was 0.89 (

P

< .01). These studies demonstrate that 13C NMR spectroscopy can be used to noninvasively assess hepatic triglyceride content in humans. This method may be clinically useful for diagnosis and follow–up of patients with hepatic steatosis.
Increased Levels of Soluble Complement Receptor 1 in Serum of Patients With Liver Diseases
Authors: Sadallah S , Giostra E , Mentha G , Schifferli J A
Published: November 2004

Complement receptor type 1 (CR1) is an integral membrane protein of many hematopoietic cells and is found in a soluble form in plasma. Preliminary data have indicated that soluble complement receptor 1 (sCR1) levels in serum were increased in patients with cirrhosis. In this study, sCR1 was measured in patients with various liver diseases with a newly established enzyme–linked immunosorbent assay (ELISA). sCR1 level was elevated in chronic active hepatitis C (24 patients, 62.6 ± 31 ng/ML; 31 normal controls, 31.4 ± 7.8 ng/mL,

P

< .001), and in cirrhosis (35 patients, 143.7 +/– 61 ng/mL,

P

< .001). The levels increased transiently in 3 patients who had amanita phalloides intoxication. In 25 patients with advanced cirrhosis (pretransplantation screening), there were significant inverse correlations between sCR1 and both the prothrombin index (rs = –.60,

P

< .002) and the aminopyrine breath test (rs = –.51,

P

< .01). Following liver transplantation, the levels dropped from 166 ± 70 to 49 ± 24 ng/mL (

P

< .0001), and serial measurements in the posttransplantation period showed a correlation with liver dysfunction, regardless of etiology. Since CR1 is not produced by hepatocytes, the most likely explanation for the increased level of sCR1 is reduced is reduced catabolism. Thus, sCR1 may be added to the short list of large glycoproteins that accumulate in liver disease.
L–Arginine Minimizes Reperfusion Injury in A Low–Flow, Reflow Model of Liver Perfusion
Authors: Jones S M , Thurman R G
Published: November 2004

A low–flow, reflow model of liver perfusion was used in the rat to investigate the effects of l–arginine on reperfusion injury in the absence of blood elements. In contrast to

in vivo

studies, l–arginine cannot minimize hypoxia by improving the microcirculation under these special conditions, but rather can only increase oxygen delivery upon reflow. During reflow, lactate dehydrogenase (LDH) release reached a new steady–state value of 35 ± 3 U/g/h in livers perfused in the absence of l–arginine.

L

–Arginine (0.1 mmol/L) significantly reduced LDH release during reflow to 14 ± 1 U/g/h; higher concentrations (1.0–3.0 mmol/L) were less effective and the arginine analogue Nomega–nitro l–arginine methyl ester (L–NAME, 0.3 mmol/L) reversed the protective effect completely. Infusion of the biologically inactive isomer D– arginine 0.1 mmol/L had no effect on the observed reperfusion injury. Malondialdehyde (MDA) release during reflow averaged 92 ± 10 nmol/g/h and was decreased significantly to 47 ± 13 nmol/g/h with l–arginine (0.1 mmol/L). Oxygen uptake during reflow was not significantly altered by l–arginine, although the time required to reach steady state values upon reflow was reduced significantly (about twofold), indicating improved microcirculation. Trypan blue distribution time, which is used to index the hepatic microcirculation, was decreased significantly from 330 ± 17 to 227 ± 31 seconds by l–arginine, an effect also blocked by l–NAME. Additionally, l–arginine, significantly increased both the rate of entry and exit of fluorescein–dextran, a dye confined to the vascular space, by approximately 50%, also reflecting improved microcirculation. Collectively, these findings indicate that l–arginine protects against hypoxia/reoxygenation injury in a blood–free perfusion model specifically during the reoxygenation period. It is likely that l–arginine rapidly removes substrates for free radical generation by improving the microcirculation.
Tissue Inhibitor of Metalloproteinase–1 Messenger Rna Expression Is Enhanced Relative to Interstitial Collagenase Messenger Rna in Experimental Liver Injury and Fibrosis
Authors: Iredale J P , Benyon R C , Arthur M J , Ferris W F , Alcolado R , Winwood P J , Clark N , Murphy G
Published: November 2004

Liver fibrosis results from a relative imbalance between synthesis and degradation of matrix proteins. We have previously described release of the protein collagenase inhibitor, tissue inhibitor of metalloproteinase–1 (TIMP–1), by culture–activated human hepatic stellate cells (HSCs). In this study, we have investigated the relative expression of TIMP–1 and interstitial collagenase in culture–activated rat HSCs and rat models of liver injury and fibrosis. The complementary DNA (cDNA) for rat TIMP–1 was obtained by homology polymerase chain reaction (PCR) and sequenced. By Northern analysis using this probe, TIMP–1 messenger RNA (mRNA) expression was up–regulated with HSC activation by culture on plastic as defined by cellular expression of procollagen–1. Interstitial collagenase mRNA was expressed in early 1. Interstitial collagenase mRNA was expressed in early culture (<4 days) but became undetectable in more activated cells (7–21 days). By activity assay of serum–free cell–conditioned media, TIMP–1 was found to be released in increasingly concentrations with duration of culture on plastic. Expression of TIMP–1 interstitial collagenase, and procollagen–1 mRNAs were studied in rat models of biliary and parenchymal injury (bile duct ligation and CC14 administration) by ribonuclease protein assay. TIMP–1 mRNA expression was increased at 6, 24 hours, and 3 days after bile duct ligation and was also shown to rise in acute CC14 liver injury and remain elevated as the liver became fibrotic. TIMP–1 expression preceded procollagen–1 expression in both models. In contrasts, interstitial collagenase mRNA levels remained similar to control values throughout both models of liver injury. Total cellular RNA from hepatocytes, HSCs, and kupffer cells freshly isolated from livers after acute CC14 injury was subjected to Northern analysis. TIMP–1 transcripts were observed in nonparenchymal cells only. We suggest that increased expression of TIMP–1 relative to interstitial collagenase by HSCs may promote progression of liver fibrosis in these rat models by preventing degradation of secreted collagens.
Reconstitution of Bile Acid Transport in the Rat Hepatoma Mcardle Rh– 7777 Cell Line
Authors: Torchia E C , Shapiro R J , Agellon L B
Published: November 2004

The liver recovers bile acids from the portal circulation primarily via an active process that is dependent on sodium ions. Hepatocytes lose the ability to transport bile acids in culture, and, in liver–derived permanent cell lines, this ability is severely reduced or absent. To study the importance of bile acids in regulating liver–specific functions (e.g., cellular bile acid and cholesterol metabolism), we have re–established active bile acid transport in cultured cells. The complementary DNA (cDNA) encoding the rat sodium/taurocholate cotransporting polypeptide (ntcp) was placed under the control of a cytomegalovirus promoter and transfected into the rat hepatoma cell line, McArdle RH–7777. Transfected cells were screened for the ability to take up [3H]–taurocholate. Clones that displayed the ability to take up taurocholate were expanded (designated McNtcp) and further characterized. The apparent Michaelis constant (Km) for taurocholate uptake was similar among the different clones. The observed maximum velocity (Vmax), however, differed and was positively correlated with the abundance of recombinant ntcp messenger RNA (mRNA). The highest level of taurocholate uptake activity observed in McNtcp cells was comparable with that of freshly isolated hepatocytes. Efflux of accumulated taurocholate from McNtcp cells proceeded in a manner similar to primary hepatocytes, indicating that McArdle RH–7777 cells have retained the ability to secrete bile acids. Moreover, taurocholate uptake in McNtcp cells was inhibited by other bile acid species. Based on the observed kinetic parameters, the reconstituted McArdle RH–7777 cells mimic the ability of primary hepatocytes to transport bile acids.
Endothelin Induced Contractility of Stellate Cells From Normal and Cirrhotic Rat Liver: Implications for Regulation of Portal Pressure and Resistance
Authors: Rockey D C , Weisiger R A
Published: November 2004

Hepatic stellate cells are similar to tissue pericytes and have been shown to be contractile. In this study, we examined the effects of known mediators of stellate cell contraction on portal pressure in rat livers after carbon tetrachloride induced injury (including cirrhosis) and investigated the contractility of stellate cells as a function of liver injury. Sarafotoxin S6C, an endothelin B (ETB) receptor agonist, had minor effects on portal pressure when perfused into normal livers at concentrations known to elicit stellate cell contraction (2 nmol/L). In contrast, both endothelin–1 (2 nmol/L) and angiotensin II (8.6 nmol/L) caused a rapid and pronounced rise in portal pressure. The effects of sarafotoxin S6C (a potent stellate cell contractile agonist) on portal pressure were greater in cirrhotic than normal liver, whereas those of angiotensin II were unchanged after liver injury. Endothelin–1 and sarafotoxin S6C induced contractility of stellate cells increased in proportion to the degree of liver injury. Contractility was greatest for stellate cells isolated from cirrhotic livers, a population of cells that displayed the most activated phenotype, as measured by immunoblot of smooth muscle alpha actin. Autoradiography of cirrhotic livers after perfusion with 125I–endothelin–1 revealed binding to cells in both sinusoidal spaces and collagenous fibrotic bands, consistent with known locations of stellate cells. Finally, the mixed endothelin–A (ETA) and ETB receptor antagonist, bosentan, reduced portal pressure in portal hypertensive animals, consistent with its inhibitory effect on stellate cell contraction. We conclude that stellate cell contractility increases with progressive liver injury and is proportional to the degree of stellate cell activation, becoming most prominent in the cirrhotic liver. Endothelin–stimulated contraction of stellate cells in cirrhotic liver may contribute to increased intrahepatic resistance and portal pressure.
Participatory management: Would it be a turning point in the history of the Gezira scheme?
Authors: Abdelhadi A. W. , Adam H. S. , Hassan Mohamed A. , Hata Takeshi
Published: November 2004

Since its establishment in 1925 decisions in the Sudan's Gezira irrigated scheme have been top‐down from the central headquarters of the Sudan Gezira Board (SGB). The irrigation system is divided into the upper system (US) that includes the dam, main, branch and major canals and the lower system that comprises the minor, tertiary and field channels. The Ministry of Irrigation and Water Resources (MOIWR) is responsible for the O&M of the US in addition to the maintenance of the Minor canals. The operation of the minor canals is handled by the SGB. The maintenance of the minor canals was given to the SGB in 1999, thus unifying O&M for the first time in 75 years. This opened the door for the O&M to be handed to tenants in a pilot project (PP) supported by the FAO during 2000–2002. Crop yields in the PP outyielded the neighboring blocks as well as the scheme average during the two years of the project. The PP is to be extended to at least one block in each of the 18 Gezira administrative groups. The PP established the base of legalization and institutional arrangements that govern the water users' activities and resulted in a great change in tenants' attitudes towards water management. Copyright © 2004 John Wiley & Sons, Ltd.
Field measurement and simulation of advance rates for continuous and surge irrigated furrows in Pakistan
Authors: Latif Muhammad , Mahmood Sajid
Published: November 2004

Field tests were conducted with inflow rates of 1.7–2.4 l s−1 to compare the advance rates both in continuous and surge‐irrigated furrows. The furrows were 149 m long, with 0.2–1.5% slopes. Water applied and rate of water advance were measured during five irrigation events. During the first irrigation, a reduction in applied water volume of 23–60% was observed in surge‐irrigated furrows compared with continuous irrigation. It was further noted during the course of the experiments that the surging effect was more pronounced during the first irrigation than in the subsequent irrigation events. However, it was noted that there would be hardly any benefit of the surge for smaller field lengths of 61 m, which are commonly used in Pakistan and many other developing countries. Results simulated by the SIRMOD model revealed that the water front advance curves matched closely with the observed ones in most surge treatments. The simulated performance efficiencies encourage the use and adaptation of surge irrigation in Pakistan, but more field studies are needed for its verification and for making concrete recommendations for its use in farmers' fields. Copyright © 2004 John Wiley & Sons, Ltd.
A water budget technique for the design of open drainage systems
Authors: Panda Rabindra Kumar , Rajput T. B. S.
Published: November 2004

A computer‐based water budget technique was developed considering the land gradient [{vertical interval between two adjacent field bunds (levees)=20 cm} ÷ the distance between the bunds] and paddy field bunds (viz. 16, 18, 20, 22, 24 cm) in its formulation for computing daily runoff from coastal paddy areas in India. The inputs used in the water budget technique consist of limited meteorological data that are easily available in India. The water budget technique was validated with the modified curve number method and the measured data collected during 2001 in a coastal paddy area of Orissa (east coast of India close to Bay of Bengal), India and its superiority was found. In most of the cases (barring a few events of 16 cm and 18 cm paddy field bunds for the water budget technique), statistically both methods differed significantly from each other while generating daily runoff. The estimate of the surface drainage coefficient (the amount of excess surface runoff water to be drained from the crop field during a 24‐hour period) for a 5‐year return period was computed as 100 mm day−1 (taking the 22 cm paddy field bund) and 109 mm day−1 in case of the water budget technique and modified curve number method, respectively. Copyright © 2004 John Wiley & Sons, Ltd.
Improved gene transfer and normalized enzyme levels in primitive hematopoietic progenitors from patients with mucopolysaccharidosis type I using a bioreactor
Authors: Pan Dao , Stroncek David F. , Whitley Chester B.
Published: November 2004

Background

One of the major barriers to the clinical application of hematopoietic stem cell (HSC) gene therapy has been relatively low gene transfer efficiency. Other inadequacies of current transduction protocols are related to their multi‐step procedures, e.g., using tissue‐culture flasks, roller bottles or gas‐permeable bags for clinical application.

Methods

In comparison with a conventional bag transduction protocol, a ‘closed’ hollow‐fiber bioreactor system (HBS) was exploited to culture and transduce human peripheral blood CD34+ progenitor cells (PBPCMPS) from patients with mucopolysaccharidosis type I (MPS I) using an amphotropic retroviral vector based on a murine Moloney leukemia virus LN prototype. Both short‐term colony‐forming cell (CFC) and long‐term culture initiating cell (LTCIC) assays were employed to determine transduction frequency and transgene expression in committed progenitor cells and primitive progenitors with multi‐lineage potentials.

Results

A novel ultrafiltration‐transduction method was established to culture and transduce enzyme‐deficient PBPCMPS over a 5‐day period without loss in viability and CD34 identity (n = 5). Significantly higher transduction efficiencies were achieved in primary CFC that derived from the HBS (5.8–14.2%) in comparison with those from gas‐permeable bags (undetectable to 1.7%; p < 0.01). Up to 15‐fold higher‐than‐normal enzyme activity was found in selected PBPCMPS‐LP1CD transductants. Moreover, higher gene transfer (4.4‐fold) and expression in very primitive progenitors were observed in products from the HBS compared with bag experiments as indicated by CFC derived from primitive LTCIC. Remarkably, with relatively modest gene transfer levels in LTCIC from HBS experiments, the expression of the IDUA transgene corrected the enzyme‐deficiency in 5‐week long‐term cultures (LTC).

Conclusions

MPS I progenitor cells achieved normalized enzyme levels in LTC after transduction in a HBS system. These studies demonstrate the advantages of a bioreactor‐transduction system for viral‐mediated stem cell gene transfer. Copyright © 2004 John Wiley & Sons, Ltd.
Improved high‐performance liquid chromatographic determination of guanidino compounds by pre‐column dervatization with ninhydrin and fluorescence detection
Authors: Buchberger Wolfgang , Ferdig Matthias
Published: November 2004

Ninhydrin has been investigated as a pre‐column derivatization reagent for guanidino compounds. The reaction takes place under strongly alkaline conditions, followed by a second step at low pH and elevated temperature. This procedure yields derivatives with favourable fluorescence properties (excitation at 390 nm, emission at 470 nm). Amino acids do not react with ninhydrin under these conditions so that the method can easily be used for biological samples. Reversed‐phase HPLC separations of the derivatives of several representative guanidino compounds in human blood have been achieved with gradients consisting of aqueous formic acid and methanol. Fluorescence detection yields quantification limits of about 20 μg L–1. Hyphenation with electrospray mass spectrometry has been used to confirm the identity of the derivatives.
Observation stimulated Raman scattering in nanocrystalline
Sc2O3 ceramics
Authors: Kaminskii A A , Bagaev S N , Ueda K , Takaichi K , Lu J , Shirakawa A , Yagi H , Yanagitani T , Eichler H J , Rhee H
Published: November 2004

Efficient room-temperature steady-state high-order
stimulated Raman scattering under picosecond pumping was excited
in highly transparent nanocrystalline ceramics based on cubic
Sc2O3. All recorded Stokes and anti-Stokes lasing components
in the visible and near-IR were identified and attributed to the
χ(3)-active vibration mode ωSRS ≈
419 cm-1 of this novel nonlinear-laser material.
Tamoxifen‐Loaded Polymeric Micelles: Preparation, Physico‐Chemical Characterization and In Vitro Evaluation Studies
Authors: Cavallaro Gennara , Maniscalco Laura , Licciardi Mariano , Giammona Gaetano
Published: November 2004

Summary: Several samples of polymeric micelles, formed by amphiphilic derivatives of PHEA, obtained by grafting into polymeric backbone of PEGs and/or hexadecylamine groups (PHEA‐PEG‐C16 and PHEA‐C16) and containing different amount of Tamoxifen, were prepared. All Tamoxifen‐loaded polymeric micelles showed to increase drug water solubility. TEM studies provided evidence of the formation of supramolecular core/shell architectures containing drug, in the nanoscopic range and with spherical shape. Samples with different amount of encapsulated Tamoxifen were subjected to in vitro cytotoxic studies in order to evaluate the effect of Tamoxifen micellization on cell growth inhibition. All samples of Tamoxifen‐loaded polymeric micelles showed a significantly higher antiproliferative activity in comparison with free drug, probably attributable to fluidification of cellular membranes, caused by amphiphilic copolymers, that allows a higher penetration of the drug into tumoral cells. To gain preliminary information about the potential use of prepared micelles as Tamoxifen drug delivery systems, studies evaluating drug release ability of micelle systems in media mimicking biological fluids (buffer solutions at pH 7.4 and 5.5) and in human plasma were carried out. These studies, performed evaluating the amount of Tamoxifen that remains in solution as a function of time, showed that at pH 7.4, as well as in plasma, PHEA‐C16 polymeric micelles were able to release lower drug amounts than PHEA‐PEG5000‐C16 ones, while at pH 5.5, the behavior difference between two kind of micelles was less pronounced.

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Atom‐Transfer Radical Polymerization: A Strategy for the Synthesis of Halogen‐Free Amino‐Functionalized Poly(methyl methacrylate) in a One‐Pot Reaction
Authors: Sadhu Veera Bhadraiah , Pionteck Jürgen , Voigt Dieter , Komber Hartmut , Fischer Dieter , Voit Brigitte
Published: November 2004

Summary: An initiator containing an alkyl bromide unit and a protected amine functional group is used with CuBr/N,N,N′,N″,N″‐pentamethyldiethylenetriamine (PMDETA), in a 1:2 molar ratio with respect to initiator concentration, in order to obtain amino‐group terminated as well as halogen‐free poly(methyl methacrylate) (PMMA) in a one‐pot atom‐transfer radical polymerization (ATRP). The terminal bromines are replaced by hydrogen atoms of the PMDETA ligand, which acts as a transfer agent. However, terminating side reactions like disproportionation or dehydrobromination occur from the beginning of the polymerization. Kinetic studies by in‐line Raman spectroscopy and off‐line 1H NMR spectroscopy revealed that the controlled character of the ATRP is lost under these conditions. The measured molecular weights were consistently higher than the theoretical ones and the molecular weight distributions are relatively broad. Thermal analysis of the obtained poly(methyl methacrylate) shows two main degradation steps, one starting from unsaturated end groups (depolymerization), and one caused by main‐chain scission, a further proof for the occurrence of terminating side reactions.

Structural analysis of PMMA by matrix‐assisted laser desorption‐ionization mass spectrometry.

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Structural analysis of PMMA by matrix‐assisted laser desorption‐ionization mass spectrometry.
Behavior of Active Sites in a Changing, Supported Metallocene Catalyst Particle: Modeling Monomer Transport and Kinetics
Authors: Chiovetta Mario G. , Estenoz Diana A.
Published: November 2004

Summary: Support‐catalyst‐polymer particles composed of millions of microparticles arranged in cells and having silica nuclei covered with metallocene‐methyl alumoxane (MAO) active sites are studied to analyze cell participation during polymerization. Main variables are the changing particle morphology and the kinetic‐diffusion effects determining local monomer availability during residence time. The phenomena were studied by means of a mathematical model used to produce a set of predictions for particles polymerizing ethylene in a toluene slurry continuous stirred tank reactor (CSTR) under various operating conditions. This information is employed to predict the micro‐ and macroparticle behavior in situations designed to explore catalyst activities, monomer availabilities and reactor conditions. Kinetic constants and concentrations range from reference values up to 6 times these figures, with reactor temperatures between 323 and 353 K and particle Reynolds numbers on a 1 to 10 relative scale. Heat transfer and temperature elevation during polymerization are predicted, with no relevant overheating observed. Morphology changes, in the form of density profiles inside the support‐catalyst‐polymer particle, are monitored with time, and their interaction with transport and reaction phenomena analyzed. Increasing catalyst activity alone may not produce proportional raises in yield; it appears more efficient to improve the monomer availability instead. High catalyst activity may produce monomer depletion at inner cells delaying their fragmentation and decreasing local polymer‐production.

Cell density vs. time for cells located at the exterior, at the center and at half the radius of the macroparticle.

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Cell density vs. time for cells located at the exterior, at the center and at half the radius of the macroparticle.
Preparation and Characterization of Organic/Inorganic Polymer Composites Based on Mg‐Silicates
Authors: Pankow Oliver , Schmidt‐Naake Gudrun
Published: November 2004

Summary: An organic‐inorganic hybrid material consisting of a 3‐(methacryloxy)propyl functionalized SiO2/MgO framework was synthesized. This hybrid was successfully reacted with styrene, butyl acrylate and butyl methacrylate via a free radical emulsion polymerization to form polymer composites. The polymer composites were investigated by means of FT‐IR spectroscopy, TGA, DSC and rheometry. It is shown that the polymer is linked covalently to the organic/inorganic hybrid. Although the polymer content is rather low, the composites exhibit a polymer‐like character and enhanced mechanical properties compared to the corresponding homopolymers.

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Morphology Dependent Double Yielding in Injection Molded Polycarbonate/Polyethylene Blend
Authors: Li Zhong‐Ming , Huang Chen‐Guang , Yang Wei , Yang Ming‐Bo , Huang Rui
Published: November 2004

Summary: Polycarbonate (PC)/polyethylene (PE) blend was injection molded at different molding temperatures. The morphological observation by scanning electronic microscope (SEM) indicated that the sample molded at 190 °C contained only uniformly dispersed spherical PC particles. The samples molded at 230 and 275 °C had a typical skin‐core structure, and there were many injection‐induced PC fibers in the subskin. While the sample molded at 190 °C had the usual stress‐strain behavior, the samples obtained at 230 and 275 °C showed apparently double yielding behavior. It was suggested that the double yielding points were morphology‐dependent. The first one was the result of the yielding of PE at low strain, and the second one was caused by the yielding of the PC fibers. Moreover, it is the frictional force in the interfaces between PC and PE that transferred the stress to the PC fibers, hence giving rise to the reinforcement of PE by PC.

Stress‐strain curves of PC/PE blends injection molded at various temperatures showing first (I) and second (II) yielding points.

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Stress‐strain curves of PC/PE blends injection molded at various temperatures showing first (I) and second (II) yielding points.
Bacillus cereus, the causative agent of an emetic type of food‐borne illness
Authors: Ehling‐Schulz Monika , Fricker Martina , Scherer Siegfried
Published: November 2004

Bacillus cereus is the causative agent of two distinct forms of gastroenteritic disease connected to food‐poisoning. It produces one emesis‐causing toxin and three enterotoxins that elicit diarrhea. Due to changing lifestyles and eating habits, B. cereus is responsible for an increasing number of food‐borne diseases in the industrial world. In the past, most studies concentrated on the diarrhoeal type of food‐borne disease, while less attention has been given to the emetic type of the disease. The toxins involved in the diarrhoeal syndrome are well‐known and detection methods are commercially available, whereas diagnostic methods for the emetic type of disease have been limited. Only recently, progress has been made in developing identification methods for emetic B. cereus and its corresponding toxin. We will summarize the data available for the emetic type of the disease and discuss some new insights in emetic strain characteristics, diagnosis, and toxin synthesis.
Molecular characteristics of Escherichia coli serogroup O78 strains isolated from diarrheal cases in bovines urge further investigations on their zoonotic potential
Authors: Ewers Christa , Schüffner Claudia , Weiß Reinhard , Baljer Georg , Wieler Lothar H.
Published: November 2004

We investigated the virulence properties and clonal relationship of 21 Escherichia coli strains of serogroup O78 isolated from diarrhoeic cattle and calves. Isolates were screened for 18 genes representing virulence features of different Escherichia coli pathotypes. None of the strains harboured enterotoxin‐genes estIa/Ib, eltIa/Ib, or Shiga toxin (stx) genes, genes involved in adhesion (eae, f5, f41) hemolysin gene hlyA or invasion gene ipaC. With a high prevalence we detected enterotoxin astA (61.9%), genes involved in iron acquisition, like fyuA, irp (each 57.1%) and iucD (81.0%), and the operon sequence of Colicin V plasmids (38.1%). Some strains possessed toxin genes cdt‐IIIB and cnf1/2 (both 14.3%), the invasion gene tia (23.8%), and the serine protease encoding gene espP (23.8%). Moreover, we could show that E. coli O78 strains under investigation were able to adhere to and invade MDBK‐cells with varying efficiencies. The results indicate that the closely related O78 strains, constituting two major PFGE‐clusters, harbor various virulence features for bovine intestinal disease but cannot be grouped into one of the common E. coli intestinal pathogenic or other pathotypes according to their virulence gene pattern. Nevertheless, the ability to adhere, invade or harbor toxin genes lets us suggest that O78 strains isolated from diarrheal cases in bovines urges further investigations on the zoonotic potential of these strains.
A 2‐path approach for odd‐diameter‐constrained minimum spanning and Steiner trees
Authors: Gouveia Luis , Magnanti Thomas L. , Requejo Cristina
Published: November 2004

In a previous article, using underlying graph theoretical properties, Gouveia and Magnanti (2003) described several network flow‐based formulations for diameter‐constrained tree problems. Their computational results showed that, even with several enhancements, models for situations when the tree diameter D is odd proved to be more difficult to solve than those when D is even. In this article we provide an alternative modeling approach for the situation when D is odd. The approach views the diameter‐constrained minimum spanning tree as being composed of a variant of a directed spanning tree (from an artificial root node) together with two constrained paths, a shortest and a longest path, from the root node to any node in the tree. We also show how to view the feasible set of the linear programming relaxation of the new formulation as the intersection of two integer polyhedra, a so‐called triangle‐tree polyhedron and a constrained path polyhedron. This characterization improves upon a model of Gouveia and Magnanti (2003) whose linear programming relaxation feasible set is the intersection of three rather than two integer polyhedra. The linear programming gaps for the tightened model are very small, typically less than 0.5%, and are usually one third to one tenth of the gaps of the best previous model described in Gouveia and Magnanti (2003). Moreover, using the new model, we have been able to solve large Euclidean problem instances that are not solvable by the previous approaches. © 2004 Wiley Periodicals, Inc.
Finite‐difference schemes for transport‐dominated equations using special collocation nodes
Authors: Fatone Lorella , Funaro Daniele , Giova Rafaella
Published: November 2004

We introduce finite‐difference schemes based on a special upwind‐type collocation grid, in order to obtain approximations of the solution of linear transport‐dominated advection‐diffusion problems. The method is well suited when the diffusion parameter is very small compared to the discretization parameter. A theory is developed and many numerical experiments are shown. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2005