Evaluation of the safety of hair essence containing 0.05% purified bee venom on the skin and eyes of rabbits.

OBJECTIVE: To investigate the safety of hair essence containing 0.05% purified bee venom (HE-PBV) on the skin and eyes of New Zealand White rabbits. METHODS: HE-PBV which contained 0.05% PBV, purified water, and glycerin, was used as the test substance. The skin-irritation test (SIT) and eye-irritation test (EIT) were conducted according to the Draize method. On the SIT, HE-PBV (0.5 mL) dropped gauze was attached both intact and abraded skin for 24 h. The other side of the skin was used as control. After 24 and 72 h, the treatment site was observed and scored according to evaluation criteria for skin reactions. On the EIT, the rabbits were divided into two groups: eye-washed (three rabbits) and non-eye-washed (six rabbits). HE-PBV (0.1 mL) was squirted into the right eye of rabbits. The left eye was untreated and used as a control. Then, 20-30-s later, the eyes of rabbits in the eye-washed group were washed with ~50 mL of physiologic (0.9%) salt solution. Then, 1, 2, 3, 4 and 7 d after the start of the EIT, the eyes and behavior of the rabbits were observed. The degree of eye irritation elicited by HE-PBV was determined in three steps and then the criteria of the classification of eye-irritation scores. RESULTS: The SIT revealed erythema and edema at the site of HE-PBV application. At 72 h, the body weight of rabbits was reduced slightly, but other symptoms (except erythema and edema) were not observed. The Primary Irritation Index score was 0.6, and HE-PBV was deemed to be a slight irritant. The EIT did not show mortality or body-weight fluctuation, but hyperemic conjunctiva and eyelid closure were noted after HE-PBV administration. Except for these results, the score for the ophthalmic response on days 1, 2, 3, 4 and 7 was 0, and HE-PBV was deemed to be a non-irritant. CONCLUSION: These data suggest that HE-PBV did not elicit eye irritation, but was a slight irritant to the skin of rabbits; the latter slight would have been due to the excipients used in manufacture of the hair essence because PBV has been shown to be safe.

Phase I dose-escalation study of copanlisib in combination with gemcitabine or cisplatin plus gemcitabine in patients with advanced cancer.

BACKGROUND: Copanlisib is a pan-class I phosphatidylinositol 3-kinase (PI3K) inhibitor with predominant PI3K-α/δ activity that has demonstrated clinical activity and manageable safety when administered as monotherapy in a phase II study. Combination therapy may overcome compensatory signalling that could occur with PI3K pathway inhibition, resulting in enhanced inhibitory activity, and preclinical studies of copanlisib with gemcitabine have demonstrated potent anti-tumour activity in vivo. METHODS: A phase I, open-label, dose-escalation study to evaluate the safety, tolerability and recommended phase II dose (RP2D) of copanlisib with gemcitabine or with cisplatin plus gemcitabine (CisGem) in patients with advanced malignancies, including an expansion cohort in patients with biliary tract cancer (BTC) at the RP2D of copanlisib plus CisGem. Copanlisib and gemcitabine were administered on days 1, 8 and 15 of a 28-day cycle; maximum tolerated dose (MTD) and RP2D of copanlisib were determined. Copanlisib plus CisGem was administered on days 1 and 8 of a 21-day cycle; pharmacokinetics and biomarkers were assessed. RESULTS: Fifty patients received treatment as follows: dose-escalation cohorts, n=16; copanlisib plus CisGem cohort, n=14; and BTC expansion cohort, n=20. Copanlisib 0.8 mg kg-1 plus gemcitabine was the MTD and RP2D for both combinations. Common treatment-emergent adverse events included nausea (86%), hyperglycaemia (80%) and decreased platelet count (80%). Copanlisib exposure displayed a dose-proportional increase. No differences were observed upon co-administration of CisGem. Response rates were as follows: copanlisib plus gemcitabine, 6.3% (one partial response in a patient with peritoneal carcinoma); copanlisib plus CisGem, 12% (one complete response and three partial responses all in patients with BTC (response rate 17.4% in patients with BTC)). Mutations were detected in PIK3CA (1 out of 43), KRAS (10 out of 43) and BRAF (2 out of 22), with phosphate and tensin homologue protein loss in 41% (12 out of 29). CONCLUSIONS: Copanlisib plus CisGem demonstrated a manageable safety profile, favourable pharmacokinetics, and potentially promising clinical response.

Voluntary inhalation of methamphetamine: a novel strategy for studying intake non-invasively.

RATIONALE: The abuse of the psychostimulant methamphetamine (MA) is associated with substantial costs and limited treatment options. To understand the mechanisms that lead to abuse, animal models of voluntary drug intake are crucial. OBJECTIVES: We aimed to develop a protocol to study long-term non-invasive voluntary intake of MA in mice. METHODS: Mice were maintained in their home cages and allowed daily 1 h access to an attached tunnel leading to a test chamber in which nebulized MA was available. Restated, if they went to the nebulizing chamber, they self-administered MA by inhalation. This protocol was compared to injected and to imposed exposure to nebulized MA, in a series of seven experiments. RESULTS: We established a concentration of nebulized MA at which motor activity increases following voluntary intake resembled that following MA injection and imposed inhalation. We found that mice regulated their exposure to MA, self-administering for shorter durations when concentrations of nebulized MA were increased. Mice acquire the available MA by repeatedly running in and out of the nebulizing chamber for brief bouts of intake. Such exposure to nebulized MA elevated plasma MA levels. There was limited evidence of sensitization of locomotor activity. Finally, blocking access to the wheel did not affect time spent in the nebulizing chamber. CONCLUSIONS: We conclude that administration of MA by nebulization is an effective route of self-administration, and our new protocol represents a promising tool for examining the transitions from first intake to long-term use and its behavioral and neural consequences in a non-invasive protocol.

Randomized phase II study of axitinib versus placebo plus best supportive care in second-line treatment of advanced hepatocellular carcinoma.

BACKGROUND: The efficacy and safety of axitinib, a potent and selective vascular endothelial growth factor receptors 1-3 inhibitor, combined with best supportive care (BSC) was evaluated in a global, randomized, placebo-controlled phase II trial in patients with locally advanced or metastatic hepatocellular carcinoma (HCC). PATIENTS AND METHODS: Patients with HCC and Child-Pugh Class A who progressed on or were intolerant to one prior antiangiogenic therapy were stratified by tumour invasion (presence/absence of extrahepatic spread and/or vascular invasion) and region (Asian/non-Asian) and randomized (2:1) to axitinib/BSC (starting dose 5 mg twice-daily) or placebo/BSC. The primary end point was overall survival (OS). RESULTS: The estimated hazard ratio for OS was 0.907 [95% confidence interval (CI) 0.646-1.274; one-sided stratified P = 0.287] for axitinib/BSC (n = 134) versus placebo/BSC (n = 68), with the median (95% CI) of 12.7 (10.2-14.9) versus 9.7 (5.9-11.8) months, respectively. Results of prespecified subgroup analyses in Asian versus non-Asian patients or presence versus absence of tumour invasion were consistent with the overall population. Improvements favouring axitinib/BSC (P < 0.01) were observed in secondary efficacy end point analyses [progression-free survival (PFS), time to tumour progression (TTP), and clinical benefit rate (CBR)], and were retained among Asian patients in the prespecified subgroup analyses. Overall response rate did not differ significantly between treatments and patient-reported outcomes favoured placebo/BSC. Most common all-causality adverse events with axitinib/BSC were diarrhoea (54%), hypertension (54%), and decreased appetite (47%). Baseline serum analyses identified potential new prognostic (interleukin-6, E-selectin, interleukin-8, angiopoietin-2, migration inhibitory factor, and c-MET) or predictive (E-selectin and stromal-derived factor-1) factors for survival. CONCLUSIONS: Axitinib/BSC did not improve OS over placebo/BSC in the overall population or in stratification subgroups. However, axitinib/BSC resulted in significantly longer PFS and TTP and higher CBR, with acceptable toxicity in patients with advanced HCC. TRIAL REGISTRATION: ClinicalTrials.gov, NCT01210495.

Successful treatment of invasive mucormycosis in a liver transplant patient by arm amputation.

Mucormycosis is an uncommon but frequently fatal infectious complication after solid organ transplantation. We describe successful treatment of invasive mucormycosis in a liver transplant recipient by wound debridement, a right above-elbow arm amputation, and antifungal medications. Early recognition, prompt operative intervention, and initiation of an appropriate antifungal treatment are very important in the management of mucormycosis, a potentially life-threatening infection.

Single kidney transplantation from young pediatric donors in the United States.

Kidney transplantation (KTX) from small pediatric donors is performed as single or en bloc. Criteria to determine when to split pediatric donor kidneys and transplant as singles are not well established. Data reported to the Scientific Registry of Transplant Recipient for donors <10 yrs from 1995 to 2007 were reviewed (n = 5079). Donors were categorized by weight group by 5 kg increments and solitary (n = 3503) versus en bloc (n = 1576). The primary outcome was overall graft survival. Results were compared as adjusted hazard ratios (aHR) relative to ideal standard criteria donors (SCDs) (defined as age 18-39 without other risk factors), non-ideal SCDs (all other SCDs) and expanded criteria donors (age 50-59 with other risk factors or age >or=60). Single KTX from donors >or= 35 kg conferred a similar risk of graft survival as ideal SCDs. Of donors 10-34 kg, risks of en bloc KTX were similar to ideal and risks of single KTX to non-ideal SCDs; single and en bloc KTXs had 7.9 and 5.2 graft losses per 100 follow-up years, respectively. Single KTX from donors >35 kg are similar to ideal SCDs. Single KTX from donors 10-35 kg are similar to non-ideal SCDs. From a resource perspective, pediatric donors 10-35 kg used as singles offer more cumulative graft years than when used en bloc.

Outcomes and utilization of kidneys from deceased donors with acute kidney injury.

Utilization and long-term outcomes of kidneys from donors with elevated terminal serum creatinine (sCr) levels have not been reported. Using data from the Scientific Registry of Transplant Recipients from 1995 to 2007, recipient outcomes of kidneys from adult donors were evaluated stratified by standard criteria (SCD; n = 82 262) and expanded criteria (ECD; n = 16 978) donor type and by sCr 2.0 mg/dL. Discard rates for SCDs were ascertained. The relative risk of graft loss was similar for recipients of SCD kidneys with sCr of 1.6-2.0 and >2.0 mg/dL, compared to 2.0 mg/dL (adjusted odds ratio [AOR] 7.04, 95% confidence interval [CI] 6.5-7.6) and 1.6-2.0 mg/dL (AOR 2.7; CI 2.5-2.9) relative to sCr

Recovery factors affecting utilization of small pediatric donor kidneys.

UNLABELLED: Kidneys from small pediatric donors are underutilized. Using data from the Scientific Registry of Transplant Recipients for donors <21 kg in which at least one organ was recovered from 1997 to 2007 (n = 3341), donor and recovery factors were evaluated by multivariate analysis for associations with (a) kidney nonrecovery and (b) transplantation of recovered kidneys. RESULTS: The proportion of kidney recoveries were 55% during liver procurements and 40% during intestine procurements amongst donors <10 kg (p < 0.01) compared to 93% and 88%, respectively, for donors weighing 10-20 kg (p = 0.003). Intestine procurement was independently associated with an 81% greater likelihood of kidney nonrecovery (p < 0.0001) and a 48% lower likelihood of transplantation (p = 0.0004). A multivariate Cox model indicated that single kidney recipients had a 63% higher risk of graft failure compared with en bloc kidney recipients (p < 0.0001); however, concurrent intestine recovery was not a significant risk factor for graft loss. Intestine recovery from donors <21 kg of age is strongly associated with higher kidney nonrecovery and lower transplantation rates. Graft survival is worse with single kidney transplantation, but is not significantly affected by intestine recovery. Small pediatric donors procurement teams should strive to increase kidney recoveries overall and en bloc recoveries in particular.

Lack of somatic alterations of MC1R in primary melanoma.

Germline variation of the melanocortin 1 receptor gene (MC1R) is a risk factor for cutaneous melanoma. Recent studies have indicated that the risk is significantly higher for melanomas with somatic BRAF mutations, suggesting that MC1R variants may have a more specific role than their demonstrated effects on skin and hair pigmentation. To address the possibility that MC1R may act like a tumor suppressor gene by creating a permissive condition for melanocytes with specific somatic mutations to proliferate or survive, we analyzed 103 primary melanomas for somatic MC1R mutations and copy number alterations. This cohort included melanomas from skin with and without chronic sun-induced damage, mucosal membranes, and acral skin (palms, soles, and subungual). We did not find somatic mutations or frequent DNA copy number alterations at the MC1R locus, nor any skewed pattern of copy number alterations that would favor one allele type over the other. In conclusion, our findings indicate that MC1R is not a frequent target of somatic alterations in melanoma.

Effect of early recurrence of hepatitis C on late biliary anastomotic stricture after liver transplantation.

The aim of the current study was to clarify whether recurrence of hepatitis C (HCV) infection affects biliary complications after liver transplantation (OLT), with special reference to late biliary anastomotic strictures (LBAS). We reviewed 665 consecutive adult OLT recipients with a choledochocholedochostomy without T-tube placement between 1990 and 2005. Biliary anastomotic stricture was confirmed by ERCP. The LBAS was defined as stricture that occurred 30 days or more after OLT. Recurrence of HCV was diagnosed by histological examination using liver biopsy specimen and confirmed by the presence of HCV-RNA. Early HCV recurrence was defined as recurrence that occurred within 6 months after OLT; LBAS occurred in 54 patients (8% of total). Mean duration from OLT to occurrence of LBAS was 6.9 months (1-44 months). Patients with HCV infection had higher occurrence of LBAS than did non-HCV patients (11% vs 5%, P = .0093). Among HCV patients, those with early HCV recurrence had exclusively high rate of LBAS (16%). In multivariate analyses, early recurrence of HCV (P < .001, relative risk [RR] 6.4), as well as occurrence of HAT (P = .0018, RR 8.0), and prolonged CIT (P = .034, RR 3.3) were independent risk factors affecting LBAS. In conclusion, patients with HCV infection have increased occurrence of LBAS after OLT. Additionally, early recurrence of HCV contributes to a higher rate of LBAS.

Laparoscopic staging and tumor ablation for hepatocellular carcinoma in Child C cirrhotics evaluated for orthotopic liver transplantation.

BACKGROUND: Surgical resection and liver transplantation remain the only treatments that offer cure for hepatoma, but are limited to those with early stage disease. Prelisting radiological staging is not always definitive. In this study, we sought to delineate the role of laparoscopy for clarification of staging in advanced cirrhotic patients when radiological assessment during evaluation for orthotopic liver transplants (OLTx) is equivocal. METHODS: Over a 3-year period, 18 patients with advanced liver insufficiency being evaluated for OLTx listing underwent laparoscopic staging when the following criteria were met: (1) lesion(s) with indeterminate size/borders, (2) an indeterminate number of lesions, or (3) lesion(s) and alpha-fero protein (AFP) less than 100 ng/ml. Patients underwent exploratory laparoscopy and laparoscopic ultrasound with biopsy, with or without ablation of lesion(s). RESULTS: Laparoscopic staging was initiated in 18 patients; four of the first six patients were converted to open procedures. Twelve patients were restaged as a result of the procedure: six down-staged and six up-staged. Stage changes were based on laparoscopic visualization of advanced disease in two, ultrasonographic clarification of tumor size/number in seven, and biopsy in three. Twelve of the 14 laparoscopic procedures included laparoscopic radiofrequency ablation while one received ethanol ablation. One patient required 2 units of red blood cells. One patient died on postoperative day 7 because of gastrointestinal bleeding. Four of the six down-staged patients underwent liver transplant, and pathological staging of the explants agreed with laparoscopic staging in all cases. CONCLUSION: Laparoscopic staging for HCC in advanced cirrhosis can clearly characterize tumor burden when preoperative radiological assessment is equivocal.

Perceptual information and attentional constraints in visual search of collision events.

This study examined the detection of collision events when multiple moving objects were present in the scene. Observers were presented with displays simulating a 3-D environment with multiple moving objects. The authors examined the ability of observers to detect collisions using a signal-detection paradigm and a visual search paradigm. The results indicated that, overall, observers were quite accurate at detecting collisions. Observers used both expansion information and static position to detect collisions, with expansion information being the more important source. Singleton search conditions were not processed in parallel, and conjunction search conditions had poorer performance than singleton search conditions. In addition, reaction times were greater for target-present trials as compared with target-absent trials. The results are interpreted in terms of 4 visual search hypotheses for collision detection when multiple moving objects are present.

Activator protein 1 activation following hypoosmotic stress in HepG2 cells is actin cytoskeleton dependent.

BACKGROUND: Following hypoosmotic stress-induced cell volume change, the actin cytoskeleton reorganizes itself. The role of this reorganization in the activation of the phosphatidylinositol 3-OH-kinase/protein kinase B/activator protein 1 (PI-3-K/PKB/AP-1) proliferative signaling cascade is unknown. Focal adhesion kinase (FAK) participates in the cytoskeleton-based activation of PI-3-K. We hypothesized that hypoosmotic stress-induced activation of PKB and AP-1 in HepG2 cells is dependent on an intact actin cytoskeleton and subsequent FAK phosphorylation. METHODS: HepG2 cells were incubated for 1 h with or without 20 microM cytochalasin D, an actin disrupter, and were then exposed for up to 30 min to hypoosmotic medium (200 mOsm/L) to induce swelling. Tumor necrosis factor alpha (1.4 nM) and medium alone served as positive and negative controls, respectively. Western blots measured cytoplasmic phosphorylated or total FAK and PKB. EMSAs measured nuclear AP-1. All experiments were performed in triplicate. RESULTS: Exposure to hypoosmotic stress resulted in activation of the following signaling messengers in a sequential fashion: (1) phosphorylation of FAK occurred by 2 min, (2) phosphorylation of PKB occurred by 10 min, (3) nuclear translocation of AP-1 occurred by 30 min. All three signaling events were abolished when these cells were pretreated with cytochalasin D. CONCLUSION: Actin reorganization following hypoosmotic stress is essential for the FAK-mediated activation of the PI-3-K/PKB/AP-1 proliferative cascade. These data delineate a possible mechanism by which the cell swelling-induced cytoskeletal changes can initiate proliferative signal transduction in human liver cancer.

Impact of cell swelling on proliferative signal transduction in the liver.

Cellular swelling has emerged as an important initiator of metabolic and proliferative changes in various cells. Because of the unique regenerative capacity of the adult liver, researchers have delineated key intracellular signals that are activated following mitogens, injury, and partial hepatectomy. Although hepatocellular swelling is commonly observed following these regenerative stimuli, only recently has the relationship between cell volume increase and proliferative activity been investigated; to date, the data implicating cell volume increase with hepatocyte regeneration has been mostly indirect. Hepatocyte swelling has been demonstrated in various clinical scenarios from sepsis, hepatic resection, ischemia-reperfusion injury, glucocorticoid excess, and hyperinsulinemia. Using various in vivo and in vitro models of hepatocyte swelling, particularly hypo-osmotic stress, investigators have demonstrated changes in cellular structure: (1) cell membrane stretch, (2) cytoskeletal microtubule and microfilament reorganization, and (3) alterations in cytoskeletal-membrane complexes. Similar studies have demonstrated a causal relationship between cell volume increase and intracellular signals: (1) activation of cytoplasmic signaling cascades such as MAPKs, PI-3-K, and PKC, (2) activation of proliferative transcription factors NF-kappaB, AP-1, STATs, C/EBPs, and (3) transcription of metabolic and immediate early genes of regeneration. Through mechanotransduction, or the translation of physical changes to chemical signals, cell volume is a potent effector of these signaling events. Growing evidence demonstrates a link between these physical and chemical changes in the swelling-mediated growth in the liver.

Protective effects of ischemic preconditioning on the cold-preserved liver are tyrosine kinase dependent.

BACKGROUND: Little data exist regarding the use of ischemic preconditioning before sustained hepatic cold storage. We hypothesized that ischemic preconditioning protects hepatic grafts via a tyrosine kinase-dependent pathway. METHODS: Six porcine livers underwent routine harvest (control). Five other livers underwent 15 min of in situ ischemia followed by 15 min of reflow before harvest (ischemic preconditioning). Another five livers were pretreated with a tyrosine kinase inhibitor (genistein) before preconditioning. Upon reperfusion and after 2 hours of cold storage, graft function, graft circulatory impairment, and markers of cellular damage were analyzed. Tissue cytoplasmic extracts were analyzed for tyrosine phosphorylation with Western blot. Significance was determined with t tests. RESULTS: Ischemic-preconditioned grafts demonstrated enhanced bile production, augmented responses to a bile acid challenge, and elevated O2 consumption (P<0.05) compared to controls. Also, preconditioned grafts demonstrated improved hepatic tissue blood flow and decreased hepatic vascular resistance (P<0.005) compared to controls. Endothelial cell preservation (factor VIII immunostain) was improved in preconditioned graft biopsies compared to controls. With genistein pretreatment, all observed improvements returned to control levels. Analysis of cytoplasmic extracts demonstrated an increase in tyrosine phosphorylation before cold ischemia in preconditioned grafts only, but not in control or genistein-pretreated grafts. CONCLUSIONS: The data indicate that ischemic preconditioning protects the liver from sustained cold ischemia and that tyrosine kinases are involved in preconditioning responses.

Protein kinase C inhibition abrogates hepatic ischemic preconditioning responses.

INTRODUCTION: A transient period of warm ischemia prior to a longer ischemic episode (ischemic preconditioning) protects the hepatic graft from cold ischemia. The mechanism for this protection is unknown, as is the role of protein kinase C in ischemic preconditioning responses. METHODS: Livers from 40 kg Yorkshire pigs were harvested and subjected to 2 h of cold ischemia (n = 6) (control). Another group of harvested livers was pretreated with a 15-min ischemic period followed by 15 min of in situ perfusion with (n = 5) or without (n = 5) a protein kinase C inhibitor, chelerythrine. Following cold ischemia, all grafts were reperfused on a perfusion circuit and the following variables evaluated: (1) hepatic graft function, (2) graft circulatory impairment, (3) hepatocellular damage, and (4) endothelial cell damage. Protein kinase C levels were also evaluated by Western blot in the cytoplasm of all grafts. RESULTS AND DISCUSSION: Ischemic preconditioned grafts demonstrate improved graft function, reduced graft circulatory impairment, and reduced endothelial cell damage as compared to cold ischemia controls. When preconditioned grafts were pretreated with chelerythrine, graft function, graft circulatory impairment, and endothelial cell damage were no different than cold ischemia controls. Ischemic preconditioned grafts demonstrated decreased levels of protein kinase C prior to cold ischemia. There was no change in protein kinase C levels in cold ischemia controls or chelerythrine-pretreated grafts prior to cold ischemia. These data indicate that modulation of protein kinase C is essential for ischemic preconditioning responses in the cold preserved hepatic graft.

Hemodynamic and metabolic variables predict porcine ex vivo liver function.

Early recognition of hepatic function during initial graft reperfusion is important in beginning hepatic support perfusions as well as in liver transplantation. We hypothesized that both hemodynamic and metabolic perfusion variables obtained immediately after reperfusion predict eventual function during liver support or transplantation. Specific hemodynamic variables, i.e., portal vein pressure and hepatic vascular resistance, as well as metabolic variables, i.e., O(2) consumption and P(CO(2)) gradients, were compared with indices of hepatic function and damage, i.e., aqueous bile production, bile lipid outputs, lactate dehydrogenase levels, and histopathology, during an ex vivo support perfusion. O(2) consumption during early reperfusion correlated directly with unstimulated bile flows (P < 0.02) and histopathology scores (P < 0.05). Hepatic venous P(CO(2)) gradients correlated inversely with unstimulated bile flows (P < 0.05). Hemodynamic variables, i.e., portal vein pressure and hepatic vascular resistance, were inversely related with taurocholate-stimulated bile flows (P < 0.05). Hemodynamic and metabolic variables of early reperfusion are useful parameters in predicting eventual effectiveness of the harvested liver for ex vivo hepatic support perfusions.

Alterations in intrahepatic hemodynamics of the harvested porcine liver.

Hemodynamic properties of a donor liver, during initial reperfusion, are associated with the degree of graft preservation injury and have been proposed to correlate with subsequent markers of liver function. In the present study, hepatic hemodynamics, that is, portal venous pressure, hepatic vascular resistance, and compliance (vascular distensibility), were characterized (1) in situ before porcine livers were manipulated, (2) after these same livers were isolated and perfused within a bypass circuit, and (3) on reperfusion after 2 hours of cold ischemia. Hepatic vascular resistance was determined in each of these three states from the portal vein pressure response to differing hepatic blood flows. In addition, the response of the same livers to norepinephrine and nitroprusside was evaluated in each condition. In the in situ and isolated perfused liver, portal venous pressure increased only modestly despite doubling of hepatic flows. After cold ischemia, the pressure response to higher flows was significantly greater and much less of a reduction in hepatic vascular resistance was noted than in studies prior to cold ischemia. Unlike livers prior to cold ischemia, the pressure response to norepinephrine was attenuated following cold ischemia. The response to nitroprusside, however, remained intact reducing the portal pressure to that of in situ livers. Therefore the portal hypertension that follows cold ischemia appears to be largely provoked by the preservation injury and not by surgical manipulation or the bypass circuit. This increment in portal pressure is responsive to a nitric oxide donor.

Hypoosmotic stress stimulates growth in HepG2 cells via protein kinase B-dependent activation of activator protein-1.

Although hypoosmotic stress-induced cell swelling activates phosphatidylinositol-3-kinase, its impact on the downstream signal protein kinase B and cell growth is unknown. Activator protein-1 is in part phosphatidylinositol-3-kinase dependent, and is important in proliferation. We hypothesized that cell swelling modulates proliferation in HepG2 cells via the protein kinase B-dependent activation of activator protein-1. HepG2 cells pretreated with or without LY294002 were exposed for up to 30 minutes to hypoosmotic medium (160 mOsm/L). Tumor necrosis factor-alpha (1.4 nmol/L) or normoosmolar medium (270 mOsm/L) served as positive and negative controls, respectively. Western immunoblots measured cytoplasmic phosphorylated and total protein kinase B. Electromobility shift assays measured nuclear activator protein-1. Methylene blue assays measured cell proliferation at 24, 48, and 72 hours after stimulation. Hypoosmotic stress phosphorylated protein kinase B by 10 minutes. Subsequently, hypoosmotic exposure stimulated activator protein-1 by 30 minutes. Pulse exposure to hypoosmotic stress potentiated HepG2 proliferation by 72 hours as compared to both negative controls and LY-inhibited cells (n = 4 per group, P = 0.009 and P = 0.004, respectively; P <0.001 analysis of variance. All three activation events were abolished with LY294002 pretreatment. In HepG2 cells, hypoosmotic stress-induced swelling stimulates proliferation via protein kinase B-mediated activation of activator protein-1. These data delineate a possible mechanism linking changes in cell volume to growth in human liver cancer.

PI-3' kinase and NF-kappaB cross-signaling in human pancreatic cancer cells.

Because tumor necrosis factor-alpha (TNF-alpha) and some chemotherapeutic agents activate both apoptosis and NF-kappaB-dependent antiapoptotic genes, they may neutralize their own antitumor effects. The cell-signaling mechanisms for such chemoresistance are not clear but may involve phosphotidylinositol-3' kinase (PI3K). To clarify this we examined whether cross-signaling between PI3K and NF-kappaB enhances the antitumor effect of TNF-alpha in human pancreatic cancer cells. Quiescent pancreatic cancer cells (Panc-1, MiaPaCa-2) with TNF-alpha, Ly294002 (PI3K inhibitor), alone or combined, were restimulated with mitogen (10% fetal calf serum [FCS] to induce cell cycle entry). Proliferation (monotetrazolium), cell cycle progression (ApoBrDU and fluorescence-activated cell sorter analysis), and apoptosis (PARP cleavage; caspase-3 activation) were measured. Akt activation (Akt kinase assay) and IkappaBalpha degradation were determined by Western blot analysis. Translocation of NF-kappaB into the nucleus was examined by EMSA, whereas an NF-kappaB/luciferase reporter gene was used to quantify NF-kappaB-dependent gene expression. Statistical analysis was carried out by means of two-tailed t test (P <0.05). PI3K inhibition significantly enhanced the antiproliferative and proapoptotic effects of TNF-alpha in both cell lines, Ly294002 also blocked TNF-alpha-induced Akt activation but failed to alter cytoplasmic IkappaBalpha degradation or subsequent NF-kappaB nuclear translocation. NF-kappaB-dependent gene expression, however, was ultimately suppressed by Ly294002, suggesting that PI3k-dependent activation of NF-kappaB is IkappaBalpha independent. PI3K inhibition can block NF-kappaB-dependent gene expression regardless of cytoplasmic IkappaBalpha/NF-kappaB activation. Because it also regulates the antitumor effects of TNF-alpha, PI3K may in part determine NF-kappaB-induced chemoresistance in human pancreatic cancer.