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V Balan

Publications and source records attributed to V Balan.

At least 19 recordsLinked to original sources
PubMed2006

Reduced priority MELD score for hepatocellular carcinoma does not adversely impact candidate survival awaiting liver transplantation.

The liver organ allocation policy of the United Network for Organ Sharing (UNOS) is based on the model for end-stage liver disease (MELD). The policy provides additional priority for candidates with hepatocellular carcinoma (HCC) who are awaiting deceased donor liver transplantation (DDLT). However, this priority was reduced on February 27, 2003 to a MELD of 20 for stage T1 and of 24 for stage T2 HCC. The aim of this study was to determine the impact of reduced priority on HCC candidate survival while on the waiting list. The UNOS database was reviewed for all HCC candidates listed after February 27, 2002, The HCC candidates were grouped into two time periods: MELD 1 (listed between February 27, 2002, and February 26, 2003) and MELD 2 (listed between February 27, 2003 and February 26, 2004). For the two time periods, the national DDLT incidence rates for HCC patients were 1.44 versus 1.53 DDLT per person-year (p = NS) and the waiting times were similar for the two periods (138.0 +/- 196.8 vs. 129.0 +/- 133.8 days; p = NS). Furthermore, the 3-, 6- and 12-month candidate, patient survival and dropout rates were also similar nationally. Regional differences in rates of DDLT for HCC were observed during both MELD periods. Consequently, the reduced MELD score for stage T1 and T2 HCC candidates awaiting DDLT has not had an impact nationally either on their survival on the waiting list or on their ability to obtain a liver transplant within a reasonable time frame. However, regional variations point to the need for reform in how organs are allocated for HCC at the regional level.

Cadaver↗
PubMed2001

Binding and activation of thiamin diphosphate in acetohydroxyacid synthase.

Acetohydroxyacid synthases (AHASs) are biosynthetic thiamin diphosphate- (ThDP) and FAD-dependent enzymes. They are homologous to pyruvate oxidase and other members of a family of ThDP-dependent enzymes which catalyze reactions in which the first step is decarboxylation of a 2-ketoacid. AHAS catalyzes the condensation of the 2-carbon moiety, derived from the decarboxylation of pyruvate, with a second 2-ketoacid, to form acetolactate or acetohydroxybutyrate. A structural model for AHAS isozyme II (AHAS II) from Escherichia coli has been constructed on the basis of its homology with pyruvate oxidase from Lactobacillus plantarum (LpPOX). We describe here experiments which further test the model, and test whether the binding and activation of ThDP in AHAS involve the same structural elements and mechanism identified for homologous enzymes. Interaction of a conserved glutamate with the N1' of the ThDP aminopyrimidine moiety is involved in activation of the cofactor for proton exchange in several ThDP-dependent enzymes. In accord with this, the analogue N3'-pyridyl thiamin diphosphate does not support AHAS activity. Mutagenesis of Glu47, the putative conserved glutamate, decreases the rate of proton exchange at C-2 of bound ThDP by nearly 2 orders of magnitude and decreases the turnover rate for the mutants by about 10-fold. Mutant E47A also has altered substrate specificity, pH dependence, and other changes in properties. Mutagenesis of Asp428, presumed on the basis of the model to be the crucial carboxylate ligand to Mg(2+) in the "ThDP motif", leads to a decrease in the affinity of AHAS II for Mg(2+). While mutant D428N shows ThDP affinity close to that of the wild-type on saturation with Mg(2+), D428E has a decreased affinity for ThDP. These mutations also lead to dependence of the enzyme on K(+). These experiments demonstrate that AHAS binds and activates ThDP in the same way as do pyruvate decarboxylase, transketolase, and other ThDP-dependent enzymes. The biosynthetic activity of AHAS also involves many other factors beyond the binding and deprotonation of ThDP; changes in the ligands to ThDP can have interesting and unexpected effects on the reaction.

Acetolactate Synthase↗
PubMed2000

Rab3D, a small GTP-binding protein implicated in regulated secretion, is associated with the transcytotic pathway in rat hepatocytes.

Rab3 isotypes are expressed in regulated secretory cells. Here, we report that rab3D is also expressed in rat hepatocytes, classic models for constitutive secretion. Using reverse transcriptase polymerase chain reaction (RT-PCR) with primers specific for rat rab3D, we amplified a 151 base pair rab3D fragment from total RNA extracted from primary cultures of rat hepatocytes. Immunoblot analysis using polyclonal antibodies to peptides representing the N- and C-terminal hypervariable regions of murine rab3D recognized a protein of approximately 25 kd in hepatocyte lysates, hepatic subcellular fractions, and tissue extracts. The distribution of rab3D was primarily cytosolic; however, only membrane-associated rab3D significantly bound guanosine triphosphate (GTP) in overlay assays. Several lines of investigation indicate that rab3D is associated with the transcytotic pathway. First, rab3D was enriched in a crude vesicle carrier fraction (CVCF), which includes transcytotic carriers. Vesicular compartments immunoisolated from the CVCF on magnetic beads coated with anti-rab3D antibody were enriched in the transcytosed form of the polymeric IgA receptor (pIgA-R), but lacked not only the pIgA-R precursor form associated with the secretory pathway, but also a Golgi marker protein. Second, indirect immunofluorescence on frozen liver sections and in polarized cultured hepatocytes localized rab3D-positive sites at or near the apical plasma membrane and to the pericanalicular cytoplasm. Finally, cholestasis induced by bile duct ligation (BDL), a manipulation known to slow transcytosis, caused rab3D to accumulate in the pericanalicular cytoplasm of cholestatic hepatocytes. Our results indicate that rab3D plays a role in the regulation of apically directed transcytosis in rat hepatocytes.

Animals↗
PubMed1999

Autoimmune liver diseases. Recurrence after liver transplantation.

PBC and AIH recur after OLTx. The recurrence of PSC is less clear. Recurrence of these diseases seems to be of relatively little importance in the short term; however, longer follow-up is required to address the significance of recurrent disease. Immunosuppression in these patients may alter the natural history of these entities in the post-transplant setting.

Autoimmune Diseases↗
PubMed1998

Detection of plum pox virus by enzyme-linked immunosorbent assay in some apricot and peach varieties and hybrids in Romania.

Plum pox virus (PPV) is a potyvirus widely spread in many species of the Prunus genus such as plum, apricot, peach, sweet cherry and others. This potyvirus causes great damage to stone fruit trees in Romania and other European countries as Hungary, Italy, Czech Republic, France, Spain, Greece, Turkey, and Slovak Republic. The Research Station for Fruit Tree Growing Baneasa in Bucharest has realized many studies on the epidemiology and spread of PPV and also on the disease symptomatology and detection possibilities. The control of sharka disease by sanitary selection measures requires corresponding detection techniques. The aim of this study was to determine the presence or absence of PPV in some apricot and peach varieties and hybrids in 1995-1997 by the enzyme-linked immunosorbent assay (ELISA) and to verify if some of our biological materials evaluated as symptom-free under field conditions for many years are also virus-free and can be considered healthy.

Enzyme-Linked Immunosorbent Assay↗
PubMed1997

Pregnancy after liver transplantation under tacrolimus.

BACKGROUND: The maternal and fetal risk of pregnancy after organ transplantation under tacrolimus has not been reported. This was prospectively studied in 27 pregnancies by 21 female liver recipients who were treated with tacrolimus before and throughout gestation. METHOD: Twenty-seven babies were born between October 1990 and April 1996. In 15 cases, samples were obtained at or after delivery and stored (-40 degrees C) for comparison of tacrolimus concentration in the maternal blood with different combinations of cord and infant venous blood, breast milk, or a section of the placenta. RESULTS: The 21 mothers had surprisingly few serious complications of pregnancy and no mortality. Two infants with 23 and 24 weeks gestation died shortly after birth. The mean birth weight of the other 25 was 2638+/-781 g after a gestational period of 36.6+/-3.3 weeks. Mean birth weight percentile for gestational age was 50.2+/-26.2 (median 40). On the day of delivery, the mean tacrolimus concentrations (ng/ml) were 4.3 in placenta versus 1.5, 0.7, and 0.5 in maternal, cord, and child plasma, and 0.6 in the first breast milk specimens. The infants had a 36% incidence of transient perinatal hyperkalemia (K+>7.0 meq/L) and a mild reversible renal impairment, which were thought to reflect in part maternal homeostasis. One newborn had unilateral polycystic renal disease (the only anomaly). All 25 babies have had satisfactory postnatal growth and development with a current mean weight percentile of 62+/-37 (median 80). CONCLUSIONS: Pregnancy by postliver transplant mothers under tacrolimus was possible with a surprisingly low incidence of the hypertension, preeclampsia, and other maternal complications historically associated with such gestations. As in previous experience with other immunosuppressive regimens, preterm deliveries were common. However, prenatal growth for gestational age and postnatal infant growth for postpartum age were normal.

Adult↗
PubMed1997

The prediction of risk of recurrence and time to recurrence of hepatocellular carcinoma after orthotopic liver transplantation: a pilot study.

Orthotopic liver transplantation (OLTx) in the presence of hepatocellular carcinoma (HCC) has been complicated by high recurrence rates. The ability to determine the risk and timing of HCC recurrence on an individual basis would greatly aid in the candidate selection process resulting in a more efficient use of donated organs and allow the individualization and better evaluation of adjuvant chemotherapy. The 214 patients who underwent OLTx in the presence of HCC were analyzed. From the 178 patients who survived more than 150 days, 71 (40%) have suffered HCC recurrence. Based on five risk factors, that is, gender, tumor number, lobar tumor distribution, tumor size, grade of vascular invasion, artificial neural network models predicting the likelihood of HCC recurrence within 1, 2, and 3 consecutive years after transplantation were developed. Based on model predictions, those combinations of risk factors that should/should not lead to recurrence were generated, allowing stratification of patients into the following three groups: 1) patients who should not suffer HCC recurrence and who should not need adjuvant therapy, 2) patients who will suffer recurrence and for whom postoperative chemotherapy significantly prolonged survival (but did not prevent recurrence), and 3) patients who may or may not suffer HCC recurrence and whose recurrence may be prevented by adjuvant chemotherapy. The outcome of OLTx for patients with HCC can be prognosticated based on a number of clinical variables. If verified through multicenter trials, these models could be made available to transplantation programs performing OLTx in the presence of HCC.

Adolescent↗
PubMed1997

Acute hepatitis E by a new isolate acquired in the United States.

OBJECTIVE: To report the first case of acute hepatitis E by a novel isolate acquired in the United States and confirmed by nucleotide sequencing. MATERIAL AND METHODS: We describe the clinical manifestations and the results of associated laboratory studies in a man who was found to have acute hepatitis E infection. RESULTS: A 62-year-old man was hospitalized because of fever, abdominal pain, and jaundice. After an initial evaluation did not provide a cause, his serum was found to be positive for IgG anti-hepatitis E virus (HEV) by three antibody assays. Serum was also positive for HEV RNA by reverse transcriptase polymerase chain reaction (PCR). Sequencing results from the PCR products demonstrated substantial differences at the nucleotide level between this strain and the known Mexican and Burmese strains. CONCLUSION: On the basis of this initial report, HEV should be considered an etiologic agent in patients with acute non-ABC hepatitis in the United States.

Acute Disease↗
PubMed1997

Sexual behaviour and HIV knowledge among Dermatology cum Genitourinary Clinic attendees, Johor Bahru, Malaysia.

A study was conducted in the Dermatology cum Genitourinary Clinic, Hospital Sultanah Aminah Johor Bahru to determine a local population's knowledge of HIV and their sexual behaviour in relation to it. A total of 231 men and 217 women were interviewed. The sexual culture seen is one of relatively late age of first sexual intercourse, low level of partner change and low level of condom use. Men reported a higher involvement in risk behaviour. Nearly all the respondents (95.8%) have heard of HIV/AIDS but had incorrect perceptions of its mode of transmission and its associations with risk groups. This study enable us to gain background information about our patients sexual behaviour and HIV knowledge. There is a need to continue HIV education to improve our public's HIV knowledge and the results of this study provides a baseline against which future educational interventions can be gauged.

Adolescent↗
PubMed1996

Rat hepatocytes transport water mainly via a non-channel-mediated pathway.

During bile formation by the liver, large volumes of water are transported across two epithelial barriers consisting of hepatocytes and cholangiocytes (i.e. intrahepatic bile duct epithelial cells). We recently reported that a water channel, aquaporin-channel-forming integral protein of 28 kDa, is present in cholangiocytes and suggested that it plays a major role in water transport by these cells. Since the mechanisms of water transport across hepatocytes remain obscure, we performed physiological, molecular, and biochemical studies on hepatocytes to determine if they also contain water channels. Water permeability was studied by exposing isolated rat hepatocytes to buffers of different osmolarity and measuring cell volume by quantitative phase contrast, fluorescence and laser scanning confocal microscopy. Using this method, hepatocytes exposed to hypotonic buffers at 23 degrees C increased their cell volume in a time and osmolarity-dependent manner with an osmotic water permeability coefficient of 66.4 x 10(-4) cm/s. In studies done at 10 degrees C, the osmotic water permeability coefficient decreased by 55% (p < 0.001, at 23 degrees C; t test). The derived activation energy from these studies was 12.8 kcal/mol. After incubation of hepatocytes with amphotericin B at 10 degrees C, the osmotic water permeability coefficient increased by 198% (p < 0.001) and the activation energy value decreased to 3.6 kcal/mol, consistent with the insertion of artificial water channels into the hepatocyte plasma membrane. Reverse transcriptase polymerase chain reaction with hepatocyte RNA as template did not produce cDNAs for three of the known water channels. Both the cholesterol content and the cholesterol/phospholipid ratio of hepatocyte plasma membranes were significantly (p < 0.005) less than those of cholangiocytes; membrane fluidity of hepatocytes estimated by measuring steady-state anisotropy was higher than that of cholangiocytes. Our data suggests that the osmotic flow of water across hepatocyte membranes occurs mainly by diffusion via the lipid bilayer (not by permeation through water channels as in cholangiocytes).

Animals↗
PubMed1995

Hepatobiliary disease in inflammatory bowel disease.

PSC is the most common and most important hepatobiliary disease seen in association with IBD. Approximately 5% of all patients with CUC have PSC, and most patients with PSC ultimately develop IBD, usually CUC. PSC and CUC appear to be associated diseases-one does not cause the other, but common pathogenic mechanisms are likely involved. PSC alone does not differ from PSC with IBD with regard to clinical, biochemical, cholangiographic, and hepatic histologic features. There is an overlap syndrome of CAH and PSC in patients with CUC suggesting that patients with CAH and CUC should have a cholangiogram. Colectomy in patients with PSC and CUC does not influence the PSC and, if done for colitic indications, should be accompanied by an ileal pouch-anal anastomosis. Serologic markers are being identified, which are frequently found in PSC with or without CUC, including markers for the dreaded complication of cholangiocarcinoma. Unfortunately, patients with PSC and CUC are doubly at risk for malignancies of the colon and biliary system. Medical therapies are being assessed that may beneficially affect both PSC and CUC, and liver transplantation is life-saving for patients with advanced PSC. Although CAH and gallstones are also found in association with IBD, they are much less common and of considerably less clinical importance than PSC associated with IBD.

Autoimmune Diseases↗
PubMed1994

RT-PCR cloning of Rab3 isoforms expressed in peritoneal mast cells.

Rab proteins are ras-like low molecular mass GTP-binding proteins, which are postulated to act as specific regulators of membrane trafficking in exocytosis and endocytosis. We have previously shown that synthetic peptides, corresponding to the effector domain of Rab3 proteins, stimulate a complete exocytotic response in mast cells. We have used a PCR-cloning strategy to investigate the presence of mRNA encoding Rab3 in mast cells. RNA based PCR was then performed on mast cell RNA using degenerate oligonucleotide primers based on two conserved sequences among Rab3 proteins. However, no PCR products were obtained, even for proteins known to be expressed in high copy numbers in mast cells (beta-actin and Fc receptor). We have found that the problem resides in the presence of mast cell secretory granule derived heparin, that copurifies with the RNA; heparin has been shown to inhibit the activity of reverse transcriptase and Taq polymerase in PCR. After treating the RNA (obtained from about 500 mast cells) with heparinase, several PCR products of varying size were obtained using primers specific for Rab3 proteins. These products were cloned and sequenced. We have found clones containing sequences that had a 100% homology at the deduced amino acid level to a portion of Rab3B and Rab3D (amino acids 16 to 83).

Amino Acid Sequence↗
PubMed1994

Screening for hemochromatosis: a cost-effectiveness study based on 12,258 patients.

BACKGROUND/AIMS: Current emphasis in hemochromatosis has focused on early detection and treatment to prevent permanent liver damage and hepatocellular carcinoma. Thus far, only normal population and high-risk groups have been screened but not patients seeking medical care. METHODS: Serum iron levels were determined in consecutive fasting blood samples collected in the morning from 12,258 Mayo Clinic patients. RESULTS: One hundred twenty-seven patients had an initial serum iron concentration > or = 180 micrograms/dL. Eight patients (age, 38-71 years; 7 men and 1 woman) had transferrin saturation > or = 62% (range, 84-99) and serum ferritin value > or = 400 micrograms/L (range, 457-4004) with no other explanation for the abnormal iron test results. Three patients (2 male and 1 female) had markedly elevated hepatic iron concentration (range, 11,080-29,719 micrograms/g dry wt) and hepatic iron index (range, 2.9-8.4) indicative of homozygous hemochromatosis. One patient who refused liver biopsy had 7 g of iron removed by phlebotomy and is likely homozygous. Two patients had hepatic iron indices < 1.5 and are probably heterozygous. The genetic status of 1 patient is indeterminate, and 1 patient with normal hepatic iron concentration and hepatic iron index had chronic active hepatitis. None had cirrhosis, diabetes, or cardiomyopathy. No patients with hemochromatosis would have been detected without this study. CONCLUSIONS: The yield in this study, 0.33 cases of 1000 screened, is approximately one tenth of the predicted homozygote frequency by recent estimates. Even at this yield, screening appears cost-effective.

Adolescent↗
PubMed1994

Effect of ursodeoxycholic acid on serum lipids of patients with primary biliary cirrhosis.

OBJECTIVE: To study the effects of ursodeoxycholic acid (UDCA) on lipid levels in patients with primary biliary cirrhosis (PBC). DESIGN: A randomized, placebo-controlled prospective trial of UDCA was conducted in 177 well-characterized patients with PBC. MATERIAL AND METHODS: The two treatment groups (placebo and UDCA) were matched at entry with respect to age, sex, histologic stage of PBC, biochemical values, and serum lipid levels. Serum cholesterol, high-density lipoprotein cholesterol, and triglyceride levels were measured at entry, 1 year, and 2 years. RESULTS: The decrease in total cholesterol level at 1 and 2 years in the UDCA-treated group was significant in comparison with that in the placebo group. Serum high-density lipoprotein cholesterol and triglyceride levels, however, were unchanged. No severe side effects from UDCA were noted. The changes in serum cholesterol levels at 2 years were directly and strongly correlated with changes in serum bilirubin concentrations (r = 0.70; P < 0.001) and inversely correlated with initial serum cholesterol levels (r = -0.86; P < 0.00001). CONCLUSION: The cholesterol-lowering effect of UDCA could be related to amelioration of the underlying liver disease or to a direct effect of the drug on the metabolism of cholesterol in patients with hypercholesterolemia.

Adult↗
PubMed1993

Histological evidence for recurrence of primary biliary cirrhosis after liver transplantation.

Whether primary biliary cirrhosis recurs after orthotopic liver transplantation remains a controversial issue. Sixty consecutive patients with primary biliary cirrhosis with at least 1 yr of follow-up after liver transplantation were studied. All patients were treated with triple-drug immunosuppression (cyclosporine, prednisone, azathioprine). Hepatic biochemical parameters and protocol liver biopsy specimens were evaluated 1 wk, 3 wk, 4 mo and yearly after orthotopic liver transplantation and at times of liver dysfunction. Antimitochondrial antibody titers and IgM levels were determined at 4 mo and yearly. At the time of last follow-up, all patients had marked symptomatic improvement compared with their pretransplant condition, and 91% of the patients had normal hepatic biochemical parameters, including serum levels of alkaline phosphatase, bilirubin, ALT and IgM. In addition, all patients had significant decreases in antimitochondrial antibody titer (p = 0.0001) and significant decreases in serum levels of IgM (p = 0.0001). Forty-one of the 60 patients had near-normal liver histological appearance. Of those with abnormal histological appearance, five patients, 2 to 6 yr after orthotopic liver transplantation, had histological features typical of a florid duct lesion, suggesting recurrent primary biliary cirrhosis. All five patients with portal granulomas had normal hepatic biochemical values and were clinically asymptomatic. Two of the five patients had persistent antimitochondrial antibody titers. We consider the documented histological changes highly suggestive of recurrence of primary biliary cirrhosis after liver transplantation but, so far, have no evidence that the condition in these patients is progressive.

Adult↗