PubMed Health⌕ Search

Biomedical subjects

B Koneru

Publications and source records attributed to B Koneru.

At least 19 recordsLinked to original sources
PubMed2001

Successful nonfreezing, subzero preservation of rat liver with 2,3-butanediol and type I antifreeze protein.

BACKGROUND: Organ cryopreservation is hindered by ice inflicted damage. Nonfreezing preservation of livers at subzero temperatures might offer advantages over current preservation. METHODS: Sprague-Dawley rats were divided into three groups. UW livers (n = 6) were stored in University of Wisconsin (UW) solution at +4 degrees C. UWB livers (n = 6) were perfused ex vivo with UW + 10% 2,3-butanediol at < or =7 degrees C and stored at -4 degrees C. AFP livers (n = 4) were preserved identical to UWB livers, except for addition of 1 mg/ml of type I antifreeze protein. After 24 h livers were perfused with Krebs-Henseleit buffer (37 degrees C) for 60 min. Bile production, O(2) consumption (O(2)C), taurocholate extraction, and lactate dehydrogenase (LDH) release during perfusion and liver adenine nucleotide content and energy charge at the end of perfusion were measured. Cell membrane integrity was determined by trypan blue infusion. RESULTS: Ice formation was prevented in all livers stored at -4 degrees C. Bile production, O(2)C, and taurocholate extraction were similar among three groups. Livers stored at -4 degrees C contained significantly more adenine nucleotides than livers stored at +4 degrees C but the energy charge was similar. LDH release was significantly greater (P < 0.05) in the AFP group vs UWB and UW (63 vs 28 and 21 mU/min/g liver, respectively). Hepatocyte and sinusoidal cell trypan blue uptake was similar in all three groups. CONCLUSIONS: Butanediol with or without AFP was effective in preventing ice formation up to 24 h in rat livers stored at -4 degrees C. Although as effective as current +4 degrees C protocols, subzero preservation for longer periods needs to be achieved prior to clinical application.

Adenosine Diphosphate↗
PubMed2001

Oxidative stress in fatty livers of obese Zucker rats: rapid amelioration and improved tolerance to warm ischemia with tocopherol.

Fatty livers in humans and rats are less tolerant of ischemia, endotoxin, and alcohol. We hypothesized that fatty livers of obese (Ob) Zucker rats are oxidatively stressed and oxidative stress could be relieved by antioxidant treatment, leading to improved tolerance to ischemia. Total glutathione (GSH), tocopherol (TOC), ascorbic acid (AA), catalase (CAT), superoxide dismutase (SOD), and selenium-glutathione peroxidase (Se-GPx) were measured in the livers of Ob and lean (Ln) Zucker rats before and after treatment with high-dose TOC and ascorbate. Also, survival in treated Ob rats following a lethal 90 minutes of partial in vivo warm ischemia was examined. Fatty livers of Ob rats contained significantly less GSH, TOC, and CAT, in comparison with livers of Ln rats. Immunoblotting showed significantly decreased CAT protein without changes in mRNA in fatty livers. There were no significant differences in AA, SOD, and Se-GPx between the 2 groups. Pretreatment with TOC and ascorbate over 48 hours completely corrected the decreases in GSH, TOC, and CAT. Most importantly, TOC with or without ascorbate pretreatment significantly improved survival in Ob rats following ischemia in a dose-dependent manner. In conclusion, TOC administration corrected the oxidative stress in fatty livers of Ob Zucker rats and improved survival following lethal ischemia. Additional studies are needed to determine the efficacy of TOC-a relatively inexpensive agent-in treating patients with fatty livers in a variety of clinical conditions, possibly including liver transplantation.

Animals↗
PubMed2000

C282Y mutation and hepatic iron status in hepatitis C and cryptogenic cirrhosis.

BACKGROUND: Increased iron deposition in liver is seen in both primary and secondary hemochromatosis. However, it is not uncommon to see significant iron deposition in a liver biopsy, explant, or autopsy specimen without any significant clinical risk factor. Because of the discovery of the candidate gene (HFE) for hereditary hemochromatosis, we may now be able to screen high-risk patient populations for the abnormal mutation (C282Y). MATERIALS AND METHODS: In this study we analyzed the livers of 50 transplant patients with a diagnosis of either hepatitis C cirrhosis or cryptogenic cirrhosis for the prevalence of the more common C282Y mutation of the HFE gene and correlated the findings to hepatic iron concentration. RESULTS: Of the 26 cases of hepatitis C cirrhosis, 3 were found to be heterozygous for the C282Y mutation. Of the 22 cases of cryptogenic cirrhosis, 1 was found to be heterozygous for the C282Y mutation. Stainable iron was increased in hepatitis C cirrhosis (76.9%) as compared to cryptogenic cirrhosis (50%) (P =. 05). Of the 3 heterozygotes with hepatitis C cirrhosis, 2 showed hepatic iron concentrations of 3+ and 4+, and 1 showed 1+. CONCLUSIONS: We conclude that patients with hepatitis C have an increased tendency to accumulate iron in the liver, and mutations in the HFE gene play a minor role in hepatic accumulation of iron in these patients.

Amino Acid Substitution↗
PubMed1998

Critical preservation injury in rat fatty liver is to hepatocytes, not sinusoidal lining cells.

BACKGROUND: Fatty livers are more prone to primary nonfunction after transplantation. We hypothesized that sinusoidal lining cells (SLCs) in fatty livers of obese Zucker rats are more susceptible to ischemia/reperfusion injury than in normal livers. METHODS: Cold University of Wisconsin solution-preserved (30 min or 24 hr) livers from obese and lean Zucker rats were perfused ex vivo for 90 min with oxygenated warm acellular buffer containing hyaluronate. Bile output, alanine transferase, and hyaluronate clearance were measured during reperfusion. Trypan blue was infused at completion of reperfusion to assess cell membrane integrity. Another group of 24-hr preserved livers were reperfused with cold hypoxic buffer to differentiate the effects of preservation from reoxygenation. RESULTS: After 30 min of preservation, fatty livers had significantly decreased flow (1.9 vs. 2.6 ml/g/min), increased resistance, decreased hyaluronate clearance (17 vs. 35 microg/g liver) and lower bile output (13 vs. 42 microl/g) in comparison with normal livers. Hepatocyte and SLC trypan blue uptake were minimal and similar in both groups. After 24 hr of preservation, flow (2.0 vs. 2.0), resistance, hyaluronate clearance, and bile output were similar in both fatty and normal livers. The SLC trypan blue uptake was increased but similar in both groups (22 vs. 20%). In contrast, a significantly greater number of hepatocytes were trypan blue-stained in fatty livers (32 vs. 0.6%), accompanied by a marked increase in lactate dehydrogenase and alanine transferase release. Hypoxic reperfusion caused a significant decrease in hepatocyte and SLC trypan blue uptake. CONCLUSIONS: Fatty livers demonstrate impaired hepatocyte and SLC function, after even a very brief preservation. With increasing preservation, hepatocytes appear to be more susceptible to injury than SLCs. Reoxygenation appears to be important in triggering this event.

Animals↗
PubMed1998

Effect of increasing gastric pH with famotidine on the absorption and oral pharmacokinetics of the inotropic agent vesnarinone.

The effect of famotidine, an H2 receptor blocker, on the oral absorption and pharmacokinetics of the novel agent vesnarinone was investigated after oral administration of 60 mg vesnarinone with and without pretreatment with intravenous famotidine. The single-blind, randomized, two-way crossover study was conducted in 12 volunteers, with a washout period of 7 days between the two treatments. A pH monitor was used to ensure that gastric pH of the subjects was < or = 3 in the absence of and > or = 5 in the presence of famotidine. A significant decrease in maximum concentration (Cmax) and increase in time to Cmax (tmax) was observed for vesnarinone during treatment with famotidine, whereas area under the concentration-time curve (AUC) was similar for both treatments. The physicochemical properties of the drug support the above observations. Therefore, therapies that increase gastric pH will affect the rate but not the extent of absorption of vesnarinone or the safety or efficacy profile of vesnarinone.

Administration, Oral↗
PubMed1997

Blood transfusions in liver recipients: a conundrum or a clear benefit in the cyclosporine/tacrolimus era?

Blood transfusions are common in patients with end-stage liver disease (ESLD), and their effects on sensitization, rejection, and liver graft survival are not well known. These effects were examined in 121 recipients of primary liver grafts, surviving > or = 30 days. Ninety-six (79%) patients received transfusions before transplantation. Transfusion recipients had significantly fewer severe or recurrent rejection episodes (18%), compared with patients who did not receive transfusions (42%, P=0.006), if the first transfusion was > or = 90 days before the transplant. Patients with alcoholic ESLD (n=49) had significantly fewer severe rejection episodes when compared with the nonalcoholic (n=72) patients (12% vs. 35%, P=0.004). The transfusion benefit was, however, more apparent and significant in the nonalcoholic (26% vs. 56% in nontransfused, P=0.02) than among the alcoholic recipients (6% vs. 25%, P=0.1). This finding is, most likely, due to a combination of a higher rate of severe rejection and the statistical power of the larger number of recipients in the nonalcoholic group. This finding is further corroborated by a multivariate analysis in which blood transfusions retained their benefit (P<0.05) independent of recipient's age and diagnosis. Graft and patient survival were not significantly different in the transfused versus nontransfused groups. Transfusion recipients had a higher panel antibody (11.4+/-23.4 vs. 2.7+/-8.1, P<0.02) but no increased risk of a positive crossmatch. In liver recipients, blood transfusions diminish the risk of rejection independent of recipient's age and the cause of ESLD.

Adult↗
PubMed1997

Recurrent familial prolonged intrahepatic cholestasis of pregnancy associated with chronic liver disease.

Four Puerto Rican sisters had recurrent prolonged cholestasis of pregnancy without preexisting or intercurrent hepatic disorders. Available information was reviewed on the course, mechanism, and sequelae of prolonged recurrent cholestasis after 14 pregnancies in the 4 sisters. Etiologic, clinical, laboratory, radiological, and morphological studies of the liver and biliary tract were assessed. Each sister had contraceptive pill-induced pruritus. Prolonged recurrent cholestasis in the eldest sister was followed by cirrhosis and death. The second and third sisters had biopsy evidence of portal triaditis and fibrosis after five and three pregnancies, respectively. Intrahepatic cholestatic cirrhosis was present after three pregnancies in the youngest sister, necessitating an orthotopic liver transplantation; a posttransplantation pregnancy was also associated with prolonged cholestasis. Recurrent prolonged intrahepatic cholestasis of pregnancy was followed by periportal fibrosis or cirrhosis in 4 sisters. This finding suggests that patients with prolonged cholestasis after pregnancy should be followed up for evidence of ongoing liver disease, should be counseled on the potential of recurrence and disease progression in future pregnancies, and should alert family members at risk of possible occurrence of the syndrome.

Adolescent↗
PubMed1996

31P nuclear magnetic resonance study of phospholipids in ischemia/reperfusion injury in a rat fatty liver model.

Obese Zucker rats are susceptible to increased hepatic ischemia/reperfusion (I/RP) injury. Increased lipid peroxidation occurs in this model with warm ischemia. We hypothesized that a severe depletion of phospholipids (PL) occurs with warm I/RP in fatty livers. Obese (Ob) and lean (Ln) Zucker rats were subjected to 90 min of in vivo partial hepatic warm I followed by RP. Total lipids extracted from one gm of liver (median lobe) taken at the end of 1, 2 and 6 hr of RP and sham (Sh) surgery (n=5 Ln & Ob) were analyzed by 202.3 MHz 31P NMR, which provided good resolution of individual PL. Obese (Sh) rats contained 22% more PL than Ln (P= < 0.01). Ischemia caused similar decreases in PL in both Ob (to 67% Sh) and Ln rats (62%). Following 2 hr RP, PL in Ob rats decreased further (46% Sh) and recovered only marginally at 6 hr (53%), in marked contrast to the rapid recovery in Ln to preischemic levels (110% Sh at both 2 and 6 hr; P=<0.001). Mole percents of individual PL did not change significantly except for lysophosphatidylcholine, which increased from 0.43 to 1.3% (Sh vs. 6 hr RP) in the Ob, but decreased from 0.98 to 0.52% in Ln animals (P = <0.001). Fatty livers thus are more vulnerable to phospholipid depletion in response to warm ischemia/reperfusion than normal livers.

Animals↗
PubMed1996

Deceptive prothrombin and activated partial thromboplastin times in alcoholic cirrhosis.

It is believed that perioperative hemorrhage, in the hepatoportal area, results from a coagulopathy. This study determined if this could be quantitated by a modified recalcification time (MRT) test developed in our laboratory. Unlike prothrombin (PT) and activated partial thromboplastin times (APTT), the MRT is performed with whole blood to ensure the role of blood cells and chemicals (particularly tissue factor, a potent procoagulant) in the coagulation process. Candidates for liver transplantation (n = 11) were studied. Samples (5 mL) of citrated venous blood were obtained from the patients. Aliquots (1 mL) from these samples were divided into groups of vials labeled C, S, and E. Groups C and S received 20 microL saline and group E, 20 microL of saline containing 10 micrograms of Escherichia coli endotoxin (055: B5W). Vial C was incubated for 10 minutes and vials S and E for 120 minutes, all at 37 degrees C. Then, the MRT was determined on 300 microL of blood from each vial after adding 40 microL of 0.1M calcium chloride. Mean MRT values (minutes +/- standard deviation) for C (MRTC), for S (MRTS), and for E (MRTE) were compared with like values from healthy controls (n = 29). Despite prolonged PT and APTT values, MRT values were shortened in patients with cirrhosis. This hypercoagulability detected by the MRT exonerates a hemorrhagic coagulopathy and possibly implicates widened and thinned gaps in the walls of the portal venous tributaries as the cause of perioperative hemorrhage.

Blood Coagulation Disorders↗
PubMed1996

Peri-operative chylous ascites.

Chylous ascites occurs when lymphatics are disrupted due to primary lymphatic disease, infection, malignancy, or chronic liver disease. It may also occur following inadvertent interruption of abdominal lymphatics during surgery involving retroperitoneal dissection. It is suggested by some that during liver transplantation, severed hepatic lymphatics should be ligated or stented to avoid post-operative pleural and abdominal accumulation of chylous fluid. The occurrence of chylous ascites and the need to ligate lymphatics after orthotopic transplantation was assessed in 180 consecutive patients subjected to this procedure. Pre-operative chylous ascites present in one patient resolved following transplantation. Three patients who required retroperitoneal dissection to complete the biliary anastomosis via choledochojejunostomy or perform a hepatic artery graft developed post-operative chylous ascites which rapidly resolved without complications. These findings indicate special attention to transacted hepatic lymphatics is not required during orthotopic liver transplantation. Chylous ascites rarely occurs after liver transplantation and its transitory development is due to retroperitoneal dissection.

Aged↗
PubMed1995

Studies of hepatic warm ischemia in the obese Zucker rat.

The effects of warm ischemia were investigated in obese Zucker rats with severe hepatic steatosis in order to develop a nontransplant fatty liver ischemia model. Obese (Ob) and lean (Ln) Zucker rats were subjected to in vivo partial hepatic warm ischemia of 45 or 90 min. Injury was assessed by serum alanine aminotransferase, animal survival, and liver histology. Liver lipids were quantified in control animals. After 90-min ischemia and 2-hr reperfusion, liver malondialdehyde was measured and neutrophils in 12 microscopic fields were counted after esterase staining. After 45 and 90 min of ischemia, Ob animals had significantly higher alanine aminotransferase at 1-hr and 24-hr reperfusion, compared with Ln animals (P < 0.01). After 90 min of ischemia, none of the Ln and 8/9 Ob animals died within 48 hr (P < 0.01). Histologically, Ob animals had more hepatocyte necrosis than did Ln animals. Hepatic neutral and phospholipid content (mg/g) in Ob versus Ln animals was 45.2 +/- 2.6 versus 8.2 +/- 0.7 (P < 0.01) and 36.2 +/- 1.9 versus 27 +/- 2.2 (P < 0.05), respectively. After reperfusion, liver malondialdehyde content increased significantly in Ob animals (8.5 +/- 0.4 vs. 12.3 +/- 0.8 pM/mg protein; P < 0.05), but not in Ln animals. Neutrophils, scant in control livers, increased significantly (P < 0.01) after ischemia/RP, but it increased to a similar degree in Ob and Ln animals. Obese Zucker rats with hepatic steatosis are more susceptible to warm ischemia/reperfusion injury than lean animals, and lipid peroxidation may be an important contributory mechanism. Further studies in this model might help to investigate the human problem.

Alanine Transaminase↗
PubMed1994

New Jersey research: frontiers of hepatology.

Diagnostic criteria and prognosis have been revised for patients with liver and biliary tract diseases. This information provides an improved knowledge base for new preventive measures, therapeutic modalities, and outcome research at UMDNJ-New Jersey Medical School Liver Center.

Biliary Tract Diseases↗