Clinical Assessment and Management of Portal Hypertension

The development of portal hypertension in a patient with cirrhosis portends a poor prognosis. Untreated or progressive portal hypertension has serious clinical outcomes, which are often fatal. It is important to recognize portal hypertension early to delay progression and to treat complications of portal hypertension as they arise. This review will focus on the clinical assessment and management of portal hypertension.

Liver transplantation in Korea: past, present, and future

PURPOSE

This study reviewed the past and present status of liver transplantation (LT) and outlooks for the future of LT in Korea.

METHOD

The first LT in Korea was successfully performed using a deceased donor graft in 1988. Pediatric and adult living donor liver transplantations (LDLTs) were initiated in 1994 and 1997, respectively. From 1988 to 2013, 10,581 LTs were performed at 40 centers, whereas LDLT accounted for 76.5% of all LTs.

RESULTS

In the early 1990s, the deceased organ donation rate was less than 1.5 per million population (PMP) per year, but it increased to 5 PMP beginning in 2008. Despite the increasing number of deceased donor liver transplantations (DDLTs), high prevalence of hepatitis B virus (HBV)-induced cirrhosis and hepatocellular carcinoma (HCC) has provoked persistent performance of adult LDLT with technical advancement including middle hepatic vein (MHV) reconstruction of right lobe graft and dual graft LDLT with 1 nationwide donor mortality.

CONCLUSION

The number of LTs in Korea in 2010 was 23.2 PMP (1042 LTs/45 million population), lower than 23.5 PMP of Spain, but higher than 20 PMP of the United States. However, future LT numbers may decrease because of lowering the HBV carrier rate (neonatal HBV universal vaccination began in 1992), new potent anti-HBV agents, and lowest birth rate (1.22 children per family) with a decrease of potential live donors.

Genetics and Genetic Biomarkers in Sporadic Colorectal Cancer

Sporadic colorectal cancer (CRC) is a somatic genetic disease in which pathogenesis is influenced by the local colonic environment and the patient's genetic background. Consolidating the knowledge of genetic and epigenetic events that occur with initiation, progression, and metastasis of sporadic CRC has identified some biomarkers that might be utilized to predict behavior and prognosis beyond staging, and inform treatment approaches. Modern next-generation sequencing of sporadic CRCs has confirmed prior identified genetic alterations and has classified new alterations. Each patient's CRC is genetically unique, propelled by 2-8 driver gene alterations that have accumulated within the CRC since initiation. Commonly observed alterations across sporadic CRCs have allowed classification into a (1) hypermutated group that includes defective DNA mismatch repair with microsatellite instability and POLE mutations in ∼15%, containing multiple frameshifted genes and BRAF(V600E); (2) nonhypermutated group with multiple somatic copy number alterations and aneuploidy in ∼85%, containing oncogenic activation of KRAS and PIK3CA and mutation and loss of heterozygosity of tumor suppressor genes, such as APC and TP53; (3) CpG island methylator phenotype CRCs in ∼20% that overlap greatly with microsatellite instability CRCs and some nonhypermutated CRCs; and (4) elevated microsatellite alterations at selected tetranucleotide repeats in ∼60% that associates with metastatic behavior in both hypermutated and nonhypermutated groups. Components from these classifications are now used as diagnostic, prognostic, and treatment biomarkers. Additional common biomarkers may come from genome-wide association studies and microRNAs among other sources, as well as from the unique alteration profile of an individual CRC to apply a precision medicine approach to care.

Anti-p21 autoantibodies detected in colorectal cancer patients: A proof of concept study

Whereas the presence of autoantibodies in cancer patients has been acknowledged, their diagnostic or therapeutic significance has yet to be established. This is due, at least in part, to the lack of robust screening techniques to detect and characterize such antibodies for further assessment. In this study, we screened colorectal cancer (CRC) patient sera for antibodies specifically targeting the key cell cycle inhibitory factor p21 encoded by the cyclin-dependent kinase inhibitor 1A (CDKN1A). Anti-p21 antibody titers were higher in CRC patient samples versus controls, correlating with a more advanced disease stage and lymph node involvement. Further, we isolated for the first time a specific human antibody fragment against p21, which could potentially be useful as a tool to study tumorigenicity in CRC patients.

A pilot study on the safety and efficacy of generic mycophenolate agent as conversion maintenance therapy in stable liver transplant recipients

PURPOSE

The patent covering mycophenolate mofetil (MMF) in Korea has expired and, thus, several generic MMF agents are now commercially available. The supply of Cellcept (Roche Korea) was interrupted at the end of 2011, so it was inevitable that a generic MMF would be used instead. During this period, we performed a prospective pilot study to examine the safety and efficacy of a generic mycophenolate agent (Myconol: Hanmi Pharmaceutical, Seoul Korea) for use as conversion maintenance therapy in stable liver transplantation (OLT) recipients.

METHODS

OLT recipients, who were treated with MMF on an outpatient basis from January 2012 to March 2012, attended follow-up interviews conducted. The patients had undergone OLT ≥ 2 years before the study, had tolerated Cellcept, and showed stable liver function. Fifty-three patients were followed up for more than 3 months after conversion to the same dose of Myconol.

RESULTS

After conversion to Myconol, 6 patients (11.3%) experienced new side effects, which disappeared when they reverted to Cellcept (n = 5) or stopped taking Myconol medication (n = 1). The side effects associated with Myconol included gastrointestinal symptoms (indigestion and diarrhea; n = 3), skin eruptions (n = 1), pruritus (n = 1), and insomnia (n = 1). The mean mycophenolic acid levels were 1.71 ± 0.88 μg/mL for Cellcept and 1.83 ± 0.91 μg/mL for Myconol, which showed a strong correlation (r(2) = 0.92, P < .001).

CONCLUSIONS

Myconol showed similar pharmacokinetics to those of Celcept, but a small proportion of patients experienced agent-specific side effects; therefore, patients should be closely monitored when taking Myconol. Also, further studies, with a greater number of patients, are required to identify the full spectrum of drug-associated side effects.

HIV-1 specific antibody titers and neutralization among chronically infected patients on long-term suppressive antiretroviral therapy (ART): a cross-sectional study

The majority of potent and broadly neutralizing antibodies against HIV-1 have been isolated from untreated patients with acute or chronic infection. To assess the extent of HIV-1 specific antibody response and neutralization after many years of virologic suppression from potent combination ART, we examined antibody binding titers and neutralization of 51 patients with chronic HIV-1 infection on suppressive ART for at least three years. In this cross-sectional analysis, we found high antibody titers against gp120, gp41, and the membrane proximal external region (MPER) in 59%, 43%, and 27% of patients, respectively. We observed significantly higher endpoint binding titers for gp120 and gp41 for patients with >10 compared to ≤10 years of detectable HIV RNA. Additionally, we observed higher median gp120 and gp41 antibody titers in patients with HIV RNA <50 copies/mL for ≤5 years. 22% of patients neutralized a HIV-1 primary isolate (HIV-1_JR-FL) and 8% neutralized a HIV-2/HIV-1 MPER chimera. Significantly greater HIV-1_JR-FL neutralization was found among patients with >10 years of detectable HIV RNA (8/20 [40.0%] versus 3/31 [9.7%] for ≤10 years, p = 0.02) and a trend toward greater neutralization in patients with ≤5 years of HIV RNA <50 copies/mL (7/20 [35.0%] versus 4/31 [12.9%] for >5 years, p = 0.08). All patients with neutralizing activity mediated successful phagocytosis of VLPs by THP-1 cells after antibody opsonization. Our findings of highly specific antibodies to several structural epitopes of HIV-1 with antibody effector functions and neutralizing activity after long-term suppressive ART, suggest continuous antigenic stimulation and evolution of HIV-specific antibody response occurs before and after suppression with ART. These patients, particularly those with slower HIV progression and more time with detectable viremia prior to initiation of suppressive ART, are a promising population to identify and further study functional antibodies against HIV-1.

Carbon nanotube mode-locked optically-pumped semiconductor disk laser

An optically pumped semiconductor disk laser was mode-locked for the first time by employing a single-walled carbon nanotube saturable absorber. Stable passive fundamental mode-locking was obtained at a repetition rate of 613 MHz with a pulse length of 1.23 ps. The mode-locked semiconductor disk laser in a compact geometry delivered a maximum average output power of 136 mW at 1074 nm.

Gastric hyperplastic polyps causing upper gastrointestinal hemorrhage in a young adult

Here, we report a case of a young man who presented with a significant upper gastrointestinal bleed treated by endoscopic removal of multiple hyperplastic polyps. Gastric hyperplastic polyps are a relatively uncommon cause of overt gastrointestinal bleeding. While most hyperplastic gastric polyps are asymptomatic, they may present with abdominal pain, iron deficiency anemia or gastric outlet obstruction. These polyps are associated with conditions such as Helicobacter pylori gastritis and atrophic autoimmune gastritis, which predispose the epithelium to chronic inflammation and epithelial repair. The patient presented to Northwestern Memorial Hospital in July 2011. The polyps were resected by clip-assisted snare polypectomy. Histopathologic assessment of the resected polyps demonstrated multiple, non-ulcerative hyperplastic polyps measuring 1.3-1.8 cm in size, without evidence of dysplasia or malignancy. This case describes a young adult patient with multiple, large gastric polyps causing overt gastrointestinal bleeding. This is a rare presentation in a young individual, as these polyps are typically identified in patients older than 60 years of age and less commonly, pediatric populations.

Abstract 3252: Divergence of activin and TGFβ-induced SMAD-independent signaling in colon cancer

Introduction: Activin and TGFβ are members of the TGFβ superfamily with growth suppressive and pro-migratory properties. While growth suppressive SMAD 2/3/4 signaling is shared, we have evidence of diverging SMAD-independent migratory signaling involving the CDK inhibitor p21. Here, we dissect the participation of respective mitogenic pathways in activin and TGFβ-specific SMAD-independent signaling in colon cancer. Methods: Colon cancer cell lines with and without SMAD4 were assessed for SMAD, PI3K and MEK pathway influences on activin or TGFβ signaling and associated effects using pharmacologic inhibition, knock-down, co-immunoprecipitation, Western blotting, and functional assays of migration. Results: Irrespective of SMAD4 status, activin-induced migration was PI3K-dependent and associated with PI3K-induced p21 downregulation, while TGFβ-induced migration was MEK1/2-dependent. Activin but not TGFβ lead to colocalization of ACVR1, ACVR2's primary binding partner, with p85, the regulatory subunit of PI3K, in an ACVR1-dependent SMAD-independent manner. Further, activin-induced p21 downregulation was PI3K dependent and associated with proteasomal degradation, while TGFβ stabilized p21 via MEK/ERK. Inhibition of proteasomal degradation of p21 lead to a decrease in migration with activin implicating p21 downregulation in activin-induced migration but not in TGFβ-induced migration. Conclusion: Activin and TGFβ diverge in their pro-migratory SMAD-independent signaling in colon cancer affecting distinct targets to include p21 and employing diverse mitogenic signals. Dissecting ligand-specific functions in colon cancer may be exploited for risk stratification or therapeutic intervention in the near future.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3252. doi:1538-7445.AM2012-3252

Microsatellite instability, EMAST, and morphology associations with T cell infiltration in colorectal neoplasia

BACKGROUND AND OBJECTIVES

Colorectal tumors are often observed with tumor infiltrating lymphocytes, presumably as a host-immune response, and patterns may segregate by types of genomic instability. Microsatellite unstable (MSI) colorectal cancers contain a pronounced lymphocyte reaction that can pathologically identify these tumors. Colorectal tumors with elevated microsatellite alterations at selected tetranucleotide repeats (EMAST) have not been examined for lymphocyte patterns.

METHODS

We evaluated a 108-person cohort with 24 adenomas and 84 colorectal cancers for MSI and EMAST. Immunohistochemical detection of CD4+ and CD8+ T cell infiltration were performed. Prognostic relevance was assessed by survival analysis.

RESULTS

CD8+ T cell infiltration in the tumor cell nest (p = 0.013) and tumor stroma (p = 0.004) were more prominent in moderately and poorly differentiated adenocarcinoma than in adenoma and well-differentiated adenocarcinoma. CD8+ T cells in the tumor cell nest (p = 0.002) and tumor stroma (p = 0.009) were at higher density in tumors with ulcerating features compared to tumors with a sessile or polypoid appearance. MSI-H tumors showed a higher density of CD8+ T cell infiltrations in tumor cell nests (p = 0.003) and tumor stroma (p = 0.001). EMAST-positive tumors showed a higher density of CD8+ T cell infiltrations than EMAST-negative tumors both in tumor cell nest (p = 0.027) and in tumor stroma (p = 0.003). These changes were not observed with CD4+ T lymphocytes. There was no difference in cancer patient survival based on density of CD8+ cells.

CONCLUSIONS

CD8+ T lymphocytes, but not CD4+ cells, were increased in tumor cell nests and the tumor stroma in both MSI and EMAST tumors, and showed higher infiltration in ulcerated tumors. CD8+ T lymphocyte infiltration is associated with both EMAST and MSI patterns, and increases with histological advancement.

Abstract 4020: Characterization of novel BARD1 splice variants in colon cancer

BARD1 is a BRCA1 binding partner with putative tumor suppressive properties. Aberrant splice variants of BARD1 have been detected in various cancers, and it has been postulated that the presence of splice variants is cancer-specific. BARD1 expression patterns and their correlation with clinical outcome have not been assessed in colon cancer.

In this study, we determined the occurrence and role of BARD1 splice variants in colon cancer. We characterized novel BARD1 splice variants and quantified the mRNA expression levels of BARD1 splice variants and full-length BARD1 in primary colon cancers and their corresponding normal tissue. Further, full-length BARD1 protein expression was correlated with clinical outcome in primary colon cancer samples.

Methods: We performed PCR on cDNA from 15 colon cancer samples and matched normal colon tissues using primer targets in the first and last exon of BARD1 mRNA. The PCR produced several bands, that were submitted for direct sequencing. In a second approach the bands were subcloned and subsequently sequenced. The sequences were analyzed and splice variants were characterized. Splice variant specific qPCR primers were designed and expression levels were quantified using optimized SYBR Green qPCR assays. Control assays were performed to assure good RNA/cDNA quality and optimal reaction conditions. In addition, mRNA expression analysis was performed on a cDNA array consisting of pooled cDNA from 16 different human tissues (prostate, heart, brain, testis, placenta, leukocytes, thymus, lung, colon, pancreas, skeletal muscle, liver, kidney, spleen, small intestine, ovary). Full-length BARD1 protein expression was assessed via immunohistochemistry in a separate cohort of 82 primary colon cancer samples. The stained slides were scanned and visualized using the Aperio ImageScope system. Expression levels were assessed and correlated with clinical outcome data.

Results: In addition to the full-length BARD1 mRNA, we now find 19 distinct BARD1 splice variants in colon cancer, the majority of which have not been previously described. 18 of the 19 splice variants lack one or more complete exons, thus creating new and specific exon-exon boundaries. Contrary to previous assumptions, these splice variants can also be found in the adjacent normal colon tissue as well as in various other normal human tissues. While BARD1 splice variants account for the majority of BARD1 mRNA, distinct variants show a cancer-specific regulation pattern. Further, loss of full-length BARD1 protein is associated with a poor prognosis (p=0.02).

Conclusion: BARD1 splice variants commonly occur in colon cancer and normal colon tissue, with distinct variants showing a cancer-specific expression pattern. Loss of the full-length BARD1 protein correlates with a poor prognosis in colon cancer, consistent with a tumor suppressive function. Taken together, we suggest that splice variant regulation may affect BARD1 function.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4020. doi:10.1158/1538-7445.AM2011-4020

Microsatellite alterations at selected tetranucleotide repeats are associated with morphologies of colorectal neoplasias

BACKGROUND & AIMS

Elevated microsatellite alterations at selected tetranucleotide repeats (EMAST) occurs during microsatellite instability (MSI) that is not associated with major defects in DNA mismatch repair (MMR) but rather the reduced (heterogenous) expression of the MMR protein hMSH3; it occurs in sporadic colorectal tumors. We examined the timing of development of EMAST during progression of colorectal neoplasias and looked for correlations between EMAST and clinical and pathology features of tumors.

METHODS

We evaluated tumor samples from a cohort of patients that had 24 adenomas and 84 colorectal cancers. EMAST were analyzed after DNA microdissection of matched normal and tumor samples using the polymorphic tetranucleotide microsatellite markers MYCL1, D9S242, D20S85, D8S321, and D20S82; data were compared with clinical and pathology findings. Traditional MSI analysis was performed and hMSH3 expression was measured.

RESULTS

Moderately differentiated adenocarcinomas and poorly differentiated adenocarcinomas had higher frequencies of EMAST (56.9% and 40.0%, respectively) than well-differentiated adenocarcinomas (12.5%) or adenomas (33.3%) (P = .040). In endoscopic analysis, ulcerated tumors had a higher frequency of EMAST (52.3%) than flat (44.0%) or protruded tumors (20.0%) (P = .049). In quantification, all tumors with >3 tetranucleotide defects lost MSH3 (>75% of cells); nuclear heterogeneity of hMSH3 occurred more frequently in EMAST-positive (40.0%) than in EMAST-negative tumors (13.2%) (P = .010).

CONCLUSIONS

EMAST is acquired during progression of adenoma and well-differentiated carcinomas to moderately and poorly differentiated carcinomas; it correlates with nuclear heterogeneity for hMSH3. Loss of hMSH3 corresponds with multiple tetranucleotide frameshifts. The association between EMAST and ulcerated tumors might result from increased inflammation.

Expression of GIV/Girdin, a metastasis-related protein, predicts patient survival in colon cancer

Metastasis accounts for the majority of cancer-related deaths. Accurate prediction of metastatic potential of tumors has been elusive, and the search for clinically useful markers continues. We previously reported that GIV/Girdin triggers tumor cell migration by virtue of a C-terminal guanine-nucleotide exchange factor motif that activates Gαi. Here we identify GIV as a metastasis-related protein whose full-length transcript (GIV-fl) is expressed exclusively in highly invasive colon, breast, and pancreatic carcinoma cells and not in their poorly invasive counterparts. A prospective, exploratory biomarker study conducted on a cohort of 56 patients with stage II colorectal cancer revealed a significant correlation between GIV-fl expression in tumor epithelium and shortened metastasis-free survival. Survival rate for patients with GIV-fl-positive tumors is significantly reduced compared with the patients with GIV-fl-negative tumors [P<0.0001; hazard ratio=0.076; CI=0.052-0.30 (95%)]. At the 5-yr mark, survival is 100% in the GIV-fl-negative group and 62 ± 9% (mean±SE; P=6×10(-5)) in the GIV-fl-positive group. Furthermore, GIV-fl expression predicts a risk of mortality independent of the microsatellite stability status, a well-established prognosticator of colorectal cancers. We conclude that GIV-fl is a novel metastasis-related protein and an independent adverse prognosticator that may serve as a useful adjunct to traditional staging strategies in colorectal carcinoma.

A G{alpha}i-GIV molecular complex binds epidermal growth factor receptor and determines whether cells migrate or proliferate

Migrating cells do not proliferate and vice versa, but the mechanism involved remains unknown. Ghosh et al. reveal how this cellular decision is made by showing that a Gα_i–GIV molecular complex interacts with EGF receptor and programs growth factor signaling, triggering migration when assembled and favoring mitosis when assembly is prevented.

Cells respond to growth factors by either migrating or proliferating, but not both at the same time, a phenomenon termed migration-proliferation dichotomy. The underlying mechanism of this phenomenon has remained unknown. We demonstrate here that Gα_i protein and GIV, its nonreceptor guanine nucleotide exchange factor (GEF), program EGF receptor (EGFR) signaling and orchestrate this dichotomy. GIV directly interacts with EGFR, and when its GEF function is intact, a Gα_i–GIV–EGFR signaling complex assembles, EGFR autophosphorylation is enhanced, and the receptor's association with the plasma membrane (PM) is prolonged. Accordingly, PM-based motogenic signals (PI3-kinase-Akt and PLCγ1) are amplified, and cell migration is triggered. In cells expressing a GEF-deficient mutant, the Gαi–GIV-EGFR signaling complex is not assembled, EGFR autophosphorylation is reduced, the receptor's association with endosomes is prolonged, mitogenic signals (ERK 1/2, Src, and STAT5) are amplified, and cell proliferation is triggered. In rapidly growing, poorly motile breast and colon cancer cells and in noninvasive colorectal carcinomas in situ in which EGFR signaling favors mitosis over motility, a GEF-deficient splice variant of GIV was identified. In slow growing, highly motile cancer cells and late invasive carcinomas, GIV is highly expressed and has an intact GEF motif. Thus, inclusion or exclusion of GIV's GEF motif, which activates Gαi, modulates EGFR signaling, generates migration-proliferation dichotomy, and most likely influences cancer progression.

Abstract B29: Expression of BARD1 predicts outcome in colon cancer

Background: The BARD1/BRCA1 heterodimer has been implicated in several different pathways crucial for maintaining genomic integrity, DNA repair and cell survival. Complex functions have been ascribed to BARD1: It acts as a chaperone that recruits BRCA1 to the nucleus to form an ubiquitin E3 ligase complex involved in DNA repair and chromosomal stability. On the other hand, BARD1 may also promote cell survival by inhibiting BRCA1-dependent apoptosis through nuclear retention of BRCA1. Mutations in the BARD1 gene, as well as aberrant expression of BARD1 splice isoforms, have been associated with poor prognosis in breast and ovarian cancer. Here, we assess the occurrence and role of BARD1 splice isoforms in colon cancer formation.

Methods: Total RNA from primary human colon cancer samples and matched normal colon tissue was extracted and reverse transcribed. Gene specific PCR primers were designed to analyze the occurrence and pattern of BARD1 splice variants in colon cancer. Splice variants were subcloned and sequenced. Protein expression of BRCA1 and BARD1 in paraffin-embedded cancer tissues was detected by immunohistochemistry and correlated with clinicopathologic parameters.

Results: mRNA analysis of primary colon cancers confirmed a specific pattern of BARD1 splice isoforms distinct from normal controls. Certain isoforms appear to be tumor specific. Full length BARD1 is upregulated in non-metastatic cancer samples compared to matched normal tissue, which is in line with its anti-apoptotic function. Interestingly, full length BARD1 is dramatically downregulated in metastatic cancer tissue supporting its role as a tumor suppressor. Immunohistochemical analysis of colon cancer samples confirmed the loss of full length BARD1 in metastatic tissues on the protein level and revealed a significant correlation (p&lt;0.05) between expression levels of BARD1 and outcome, in which low expression of BARD1 is associated with a worse prognosis.

Conclusion: Our results suggest critical roles for the BRCA1 chaperone BARD1 in colon cancer formation. Alternative splice variants of BARD1 commonly occur in colon cancer tissue and expression of full-length BARD1 is differentially regulated along the cancer-metastasis axis affecting cancer outcome. We hypothesize that in colon cancer tissue, BRCA1 function critically depends on BARD1 expression.

Citation Information: Clin Cancer Res 2010;16(7 Suppl):B29

A national survey on the practice and outcomes of mechanical ventilation in Korean intensive care units

A study was undertaken to describe the practice and outcomes of mechanical ventilation throughout Korea. This prospective cohort study was conducted over a three-month period enrolling patients (n = 519) who received mechanical ventilation for more than 72 hours in 21 university hospital intensive care units throughout Korea. The most common indication for mechanical ventilation was acute respiratory failure. The most common cause of acute-on-chronic respiratory failure was tuberculous lung disease. The most common initial mode for ventilation was volume-controlled ventilation. The mean tidal volume of acute respiratory distress syndrome patients was 7.6 ml/kg of the predicted body weight and the mean positive end-expiratory pressure was 9.4 cmH20. The weaning success rate at 28 days was 50.3%. Pressure support and the T-piece were most commonly used as initial and final weaning modes respectively. Preventive measures against deep vein thrombosis during mechanical ventilation were performed more frequently in intensive care units with full-time critical care physicians than those without such physicians. Multivariate analysis showed that the APACHE II score, indication for mechanical ventilation, respiratory rate at 72 hours, enteral feeding and prophylaxis of deep vein thrombosis were prognostic factors for survival. In Korean intensive care units, tuberculous lung disease remains an important cause for mechanical ventilation. The practice of mechanical ventilation in Korean intensive care units in general appeared to comply with the current international recommendations with regard to lung protection and weaning. However, intensive care units lacking critical care physicians seemed to be adopting fewer ancillary measures, such as deep vein thrombosis prophylaxis.

Activin type 2 receptor restoration in MSI-H colon cancer suppresses growth and enhances migration with activin

BACKGROUND & AIMS

Colon cancers with high-frequency microsatellite instability (MSI-H) develop frameshift mutations in tumor suppressors as part of their pathogenesis. ACVR2 is mutated at its exon 10 polyadenine tract in >80% of MSI-H colon cancers, coinciding with loss of protein. ACVR2 transmits the growth effects of activin via phosphorylation of SMAD proteins to affect gene transcription. The functional effect of activin in colon cancers has not been studied. We developed and characterized a cell model in which we studied how activin signaling affects growth.

METHODS

hMLH1 and ACVR2 mutant HCT116 cells were previously stably transferred with chromosome 2 (HCT116+chr2), restoring a single regulated copy of wild-type ACVR2 but not hMLH1. Both HCT116+chr2 and parental HCT116 cells (as well as HEC59 and ACVR2 and hMSH2 complemented HEC59+chr2 cells) were assessed for genetic complementation and biologic function.

RESULTS

HCT116+chr2 cells and HEC59+chr2 cells, but not ACVR2-mutant HCT116 or HEC59 cells, acquired wild-type ACVR2 as well as expression of ACVR2 wild-type messenger RNA. Complemented ACVR2 protein complexed with ACVR1 with activin treatment, generating nuclear phosphoSMAD2 and activin-specific gene transcription. ACVR2-restored cells showed decreased growth and reduced S phase but increased cellular migration following activin treatment. ACVR2 small interfering RNA reversed these effects in complemented cells.

CONCLUSIONS

ACVR2-complemented MSI-H colon cancers restore activin-SMAD signaling, decrease growth, and slow their cell cycle following ligand stimulation but show increased cellular migration. Activin is growth suppressive and enhances migration similar to transforming growth factor beta in colon cancer, indicating that abrogation of the effects of activin contribute to the pathogenesis of MSI-H colon cancers.

BMP-induced growth suppression in colon cancer cells is mediated by p21WAF1 stabilization and modulated by RAS/ERK

Bone morphogenetic proteins (BMPs) regulate cell differentiation, proliferation, and apoptosis through a canonical SMAD signaling cascade. Absence of BMP signaling causes the formation of intestinal juvenile polyps in the colon cancer-prone syndrome familial juvenile polyposis. As sporadic colon cancers appear to have intact BMP signaling, we evaluated if K-RAS, driving a mitogenic pathway frequently activated in colon cancer, negatively affects BMP growth suppression. We treated non-tumorigenic but activated RAS/ERK FET cells with BMP2, and in combination with pharmacological or genetic inhibition of RAS/ERK, examined BMP-SMAD signaling, transcriptional activity, and cell growth, and also assessed p21(WAF1) mRNA, transcriptional activation, and protein levels. BMP2 increased nuclear phospho-SMAD1 2-fold, which increased another 2-3 fold when RAS/ERK was inhibited. BMP2 increased BMP-specific SMAD transcriptional activity 2-fold over control and decreased cell growth, but inhibition of RAS/ERK further enhanced BMP-specific transcriptional activity by an additional 1.5-2 fold and enhanced growth suppression by 20%. BMP-induced growth suppression is mediated in part by p21(WAF1), not by transcriptional upregulation but by improved p21 protein stability, which is inhibited by RAS/ERK. In colon cancer cells, BMP-SMAD signaling and growth suppression is facilitated by p21(WAF1) but modulated by oncogenic K-RAS to reduce the growth suppression directed by this pathway.

Bone morphogenetic protein signaling and growth suppression in colon cancer

Bone morphogenetic proteins (BMPs) are members of the transforming growth factor-beta superfamily, which utilize BMP receptors and intracellular SMADs to transduce their signals to regulate cell differentiation, proliferation, and apoptosis. Because mutations in BMP receptor type IA (BMPRIA) and SMAD4 are found in the germline of patients with the colon cancer predisposition syndrome juvenile polyposis, and because the contribution of BMP in colon cancers is largely unknown, we examined colon cancer cells and tissues for evidence of BMP signaling and determined its growth effects. We determined the presence and functionality of BMPR1A by examining BMP-induced phosphorylation and nuclear translocation of SMAD1; transcriptional activity via a BMP-specific luciferase reporter; and growth characteristics by cell cycle analysis, cell growth, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide metabolic assays. These assays were also performed after transfection with a dominant negative (DN) BMPR1A construct. In SMAD4-null SW480 cells, we examined BMP effects on cellular wound assays as well as BMP-induced transcription in the presence of transfected SMAD4. We also determined the expression of BMPR1A, BMP ligands, and phospho-SMAD1 in primary human colon cancer specimens. We found intact BMP signaling and modest growth suppression in HCT116 and two derivative cell lines and, surprisingly, growth suppression in SMAD4-null SW480 cells. BMP-induced SMAD signaling and BMPR1A-mediated growth suppression were reversed with DN BMPR1A transfection. BMP2 slowed wound closure, and transfection of SMAD4 into SW480 cells did not change BMP-specific transcriptional activity over controls due to receptor stimulation by endogenously produced ligand. We found no cell cycle alterations with BMP treatment in the HCT116 and derivative cell lines, but there was an increased G1 fraction in SW480 cells that was not due to increased p21 transcription. In human colon cancer specimens, BMP2 and BMP7 ligands, BMPRIA, and phospho-SMAD1 were expressed. In conclusion, BMP signaling is intact and growth suppressive in human colon cancer cells. In addition to SMADs, BMP may utilize SMAD4-independent pathways for growth suppression in colon cancers.

Endogenous urinary steroids in premenopausal women with uterine leiomyomas

OBJECTIVES

To study the effect of endogenous steroids on the presence of uterine leiomyomas.

METHODS

Urine samples of 27 premenopausal women with leiomyomas and 25 age-matched healthy premenopausal women were collected. The concentration of estrogens and androgens in the urine samples of the two groups were determined using a gas chromatography mass spectrometer and the two groups were compared. To study metabolic changes in patients indirectly, the concentration ratios of precursor metabolite to product metabolite of the two groups were also compared.

RESULTS

Urinary concentrations of 17beta-estradiol, 5-androstene-3beta, 16beta, 17beta, triol, 11-keto-ethiocholanolone, 11beta-hydroxy-androsterone, 11beta-hydroxy-etiocholanolone, THS, THA, THE, alpha-cortol and beta-cortol were significantly higher in patients than in controls. The concentration ratios of 17beta-estradiol/estrone and 11/beta-hydroxy-ethiocholanolone/11beta-hydroxy-androsterone increased in patients.

CONCLUSIONS

The presence of uterine leiomyomas correlates with an increase in urinary concentrations of estrogens and androgens, and it appears to be caused by a decrease in patients' metabolism of steroids.

Relationship between urinary profile of the endogenous steroids and postmenopausal women with stress urinary incontinence

AIMS

The aims of this study were to investigate whether endogenous steroid hormones are (1) related to pathogenesis of stress urinary incontinence after menopause, (2) are related to severity of stress urinary incontinence, and (3) are related to prognostic parameters of stress urinary incontinence.

METHODS

Twenty post-partum women with clinically diagnosed stress urinary incontinence and 20 age-matched postmenopausal women without stress urinary incontinence (control group) were evaluated. We compared urinary profile of the endogenous steroid hormones patients with stress urinary incontinence and controls, and between grade I and grade II of stress urinary incontinence. We also investigated the relationship between urinary profile of the endogenous steroid hormones and prognostic parameters of stress urinary incontinence (maximal urethral closure pressure, functional urethral length, Valsalva leak point pressure, cough leak point pressure, posterior urethrovesical angle, bladder neck descent, and stress urethral axis). The ages of the patients and those in the control group were 64.3 +/- 5.6 and 57.5 +/- 3.8 years old and the body mass indexes were 24.96 +/- 3.14 and 22.11 +/- 2.73 kg/m2 in patients and in normal subjects, respectively. Nine patients were grade I and 11 were grade II. Estrone and 17beta-estradiol only were detected in all subjects, regardless of control or patient group. It is noteworthy that there were no significant differences (P > 0.05) in the levels of estrone and 17beta-estradiol in the urine of postmenopausal normal subjects compared with in the urine of postmenopausal patients with urinary incontinence. E2/E1 ratio was not different between the two groups (P > 0.05). Among the objective steroids, DHEA, Delta4-dione, Delta5-diol, Te, DHT, 16alpha-DHT, 11-keto An, THDOC, and THB were not detected either in the urine of normal subjects and nor in the urine of the patients. After comparing androgen levels between normal subjects and patients, no significant differences (P>0.05) were detected, except for 5alpha-THB and 5alpha-THF. Neither 5alpha-THB or 5alpha-THF were detected in the patients' urine. Et/An (11beta-OH Et/11beta-OH An) concentration ratios were not significantly different between the two groups, either (P > 0.05). There were not significant differences of concentrations (micromol/g creatinine) of urinary steroids between grade I and grade II of stress urinary incontinence. Pregnanediol was significantly related to bladder neck descent in supine and sitting positions (R = 0.79, P = 0.01, and R = 0.73, P = 0.03, respectively), and pregnanetriol was significantly related to maximal urethral closure pressure and functional urethral length (R = 0.68, P = 0.04, and R = -0.79, P = 0.01, respectively). Androsterone was significantly related to bladder neck descent in supine and sitting positions (R = 0.68, P = 0.04, and R = 0.78, P = 0.01, respectively). 5-AT was significantly related to bladder neck descent in sitting position and stress urethral axis (R = 0.72, P = 0.03, and R = -0.71, P = 0.03). 11-keto Et was significantly related to bladder neck descent in supine and sitting positions and related to stress urethral axis (R = 0.82, P = 0.01, and R = 0.81, P = 0.01, R = -0.67, P = 0.04, respectively). THS was significantly related to bladder neck descent in supine and sitting positions and related to stress urethral axis (R = 0.76, P = 0.02, and R = 0.74, P = 0.02, R = -0.68, P = 0.04, respectively). THE was significantly related to bladder neck descent in sitting position (R = 0.67, P = 0.04).beta-Tetrahydrocortisol/alpha-tetrahydrocortisol (beta-THF/alpha-THF) and alpha-cortol were significantly related to maximal urethral closure pressure and functional urethral length (R = 0.74, P = 0.02, and R = -0.92, P = 0.01; R = 0.71, P = 0.36, and R = -0.87, P = 0.000, respectively). 17beta-estradiol (E2) was significantly related to bladder neck descent in supine position (R = -0.62, P = 0.04) and 17beta-estradiol/estrone (E2/E1) was significantly related to cough leak point pressure (R = 0.79, P = 0.01). In conclusion, the urinary concentrations of endogenous steroid metabolites in postmenopausal patients with stress urinary incontinence were not significantly different from normal patients and were not significantly different between grade I and grade II patients with stress urinary incontinence. Some endogenous steroid metabolites were positively or negatively significantly related to prognostic parameters of stress urinary incontinence.

Urinary profile of endogenous steroids in postmenopausal women with stress urinary incontinence

OBJECTIVE

To predict the role of estrogen in prevention of and therapy for stress urinary incontinence by comparing the urinary levels of estrogens and androgens and, to indirectly evaluate metabolism of estrogens and androgens by comparing the concentration ratios of precursor metabolites with those in controls (normal subjects).

STUDY DESIGN

Urine samples collected for 24 hours were obtained from postmenopausal women with stress urinary incontinence (n = 20) and from age-matched, postmenopausal, normal female subjects (n = 14). The urinary levels of 20 estrogens and 25 androgens were analyzed by gas chromatography/mass spectrometry.

RESULTS

The urinary levels of androgens were significantly higher in patients with stress urinary incontinence than normal subjects, and the urinary levels of estrogens were somewhat higher in patients than normal subjects. However, there were no significant differences between the groups, nor were there significant differences in the metabolism of estrogens and androgens between two groups.

CONCLUSION

The urinary levels of endogenous steroids were rather higher in patients with stress urinary incontinence than in normal subjects, so it appears that estrogen should not play a significant role in prevention of and therapy for stress urinary incontinence.

Nitric oxide prevents the IFN-gamma/LPS-induced hepatotoxicity in a protein kinase G-independent manner

Although it has been well known that the role of LPS on hepatotoxicity is mediated through TNF-alpha, the direct cytotoxic effect of LPS on IFN-gamma-primed hepatocytes has not yet been clearly demonstrated. Here, we demonstrate that the IFN-gamma-mediated death of murine embryonic liver BNL CL2 cells is potentiated by LPS (0.5 microg/ml). In addition, an exogenous NO donor, sodium nitroprusside (SNP) significantly prevents cell death induced by IFN-gamma alone or IFN-gamma plus LPS (IFN-gamma/LPS) in a dose-dependent manner over 25 microM. SNP significantly blocked the death of BNL CL2 cells only when it was added within 12 hr after treatment of IFN-gamma and IFN-gamma/LPS. The preventive effect of SNP occurred in parallel with the suppression of caspase 3-like protease activation. We have also demonstrated that a relatively high concentration as well as an appropriate period of exposure to NO may be critical to maintain cell viability from the cytotoxic effect of IFN-gamma and IFN-gamma/LPS. Furthermore, the preventive effect of SNP on IFN-gamma/LPS-induced cell death is mediated by a protein kinase G (PKG)-independent manner.

Gamma-interferon (IFN-gamma) augments apoptotic response to mistletoe lectin-II via upregulation of Fas/Fas L expression and caspase activation in human myeloid U937 cells

Mistletoe lectin-II, a major composition of Korean mistletoe (Viscum album coloratum), is known as a potent apoptosis inducer. The previous research has demonstrated that Korean mistletoe lectin-II induces apoptosis via c-Jun N terminal kinase (JNK) activation in human myeloid U937 cells. The purpose of this research is to prove the synergistic action of mistletoe lectin-II and interferon-gamma (IFN-gamma) in the apoptotic cytotoxicity of U937. When U937 cells were treated with mistletoe lectin-II after being differentiated by IFN-gamma, the proteolytic activity of caspase-3 and 9 was markedly elevated and that of caspase-8 was prolonged for 18 hr. The activation of caspase-3-like protease requires the earlier cleavage of poly(ADP-ribose) polymerase(PARP). Caspase-1 was, however, not activated during the resting phase and nor in IFN-gamma-differentiated U937 cells. Western blot analysis revealed that, in IFN-gamma-differentiated U937 cells, the expression of Fas (CD95/APO-1) & Fas ligand(FasL) increases the apoptotic sensitivity against Mistletoe lectin-II. Fas (CD95/APO-1) & FasL were not significantly induced solely by mistletoe lectin-II. Furthermore the activity of JNK1 in U937 cells was also markedly increased with IFN-gamma-differentiation, compared to that of the control. These results suggest that the IFN-gamma-differentiation of U937 cells increases the susceptibility to mistletoe lectin-II-induced apoptosis.

Activation of c-Jun N-terminal kinase 1 (JNK1) in mistletoe lectin II-induced apoptosis of human myeloleukemic U937 cells

Extracts of mistletoe (Viscum album var. coloratum) have been used for several decades as an anticancer immunomodulating agent in clinical fields. However, the mechanism by which the plant extracts kill tumor cells has remained elusive. We investigated the direct effects of beta-galactoside- and N-acetyl-d-galactosamine-specific mistletoe lectin II in inducing apoptotic death of U937 cells. Three distinct components of mistletoe, including beta-galactoside- and N-acetyl-D-galactosamine-specific lectin II (60 kDa), polysaccharides, and viscotoxin (5 kDa), induced apoptotic cell death, characterized by DNA ladder pattern fragmentation of U937 cells at 12 hr after treatment. Consistent with apoptosis of the cells, mistletoe extracts markedly increased the phosphotransferase activity of c-Jun N-terminal kinase 1 (JNK1)/stress-activated protein kinase (SAPK) in U937 cells. Among the three components, lectin II was the most potent in inducing apoptosis as well as JNK1 activation of U937 cells in a dose- and time-dependent manner. Catalytic activation of JNK1 induced by mistletoe lectin II was inhibited by the addition of peptide aC-DEVD-CHO, but not by aC-YVAD-CHO. In addition, mistletoe lectin II induced apoptosis in a variety of cell types including Jurkat T cells, RAW 264.7 cells, HL-60 cells, DLD-1 cells, and primary acute myelocytic leukemic cells.

LPS induces direct death of IFN-gamma primed murine embryonic hepatocyte, BNL CL2 cells in a TNF-alpha independent manner

Although it has been well known that the role of LPS on liver damage is mediated through TNF-alpha, the mechanism by which LPS modulates the cytotoxicity of IFN-gamma on hepatocytes has not yet been clearly demonstrated. Here, we demonstrate that IFN-gamma mediated apoptosis in murine embryonic hepatocyte BNL CL2 cells is potentiated by the addition of LPS (0.5 microg/ml). Consistently, LPS markedly increases the catalytic activity of caspase 3-like protease but not caspase 1-like protease in IFN-gamma treated cells. In addition, TNF-alpha alone does not affect cell viability but rather it potentiates the cytotoxic effect of IFN-gamma on BNL CL2 cells. However, the cell viability of IFN-gamma/LPS treated cells is affected by the addition of polymyxin B but not by TNF binding protein I (TNF-BPI). These data suggest that the lipid moiety of LPS may mediate direct cytotoxicity of BNL CL2 cells in a TNF-alpha independent manner.

Molecular cloning of a gene encoding the thermoactive levansucrase from Rrahnella aquatilis and its growth phase-dependent expression in Eescherichia coli

A levansucrase gene (lsrA) from Rahnella aquatilis ATCC33071 was isolated from a genomic library and the nucleotide sequence of the lsrA structural gene was determined. lsrA is composed of 1248 bp and encodes 415 amino acid residues with a calculated molecular mass of 45.9 kDa. Although the amino acid sequence of lsrA gene showed good conservation with the sequences of reported levansucrases and of the conserved regions thought to be implicated in the enzyme activity, comparison of the deduced amino acid sequences certified the dissimilarity of the proteins from Gram-negative and Gram-positive bacteria. The lsrA gene was expressed from its own promoter in Escherichia coli in an active form. The lsrA expression in E. coli-pRL1CPR was affected by the growth phase of cells: it was repressed in the early phase of growth, but was significantly stimulated during the entrance of cells into the late phase of growth. The growth-phase-dependent fashion of lsrA expression was altered in a constitutive-like fashion by the deletion of an upstream region of lsrA (pNd137), suggesting that the growth-phase dependent expression of lsrA was mediated by the deleted upstream region.

Prolonged delivery of nicotine in rats via nasal administration of proliposomes

In order to achieve a prolonged delivery of nicotine to the systemic circulation, proliposomes containing nicotine base (NB-proliposomes) or nicotine hydrogen tartarate salt (NS-proliposomes) and a mixture of powdered nicotine hydrogen tartarate salt and sorbitol (1:9 mixture, MP) were administered intranasally to rats at a nicotine dose of 1 mg/kg. Proliposomes, lipid-sorbitol mixtures that form liposomes upon contact with water, were prepared according to previously established methods, and the mixture (MP) was prepared by mixing NS powder with sorbitol particles (105-350 micrometer in size). Nasal absorption of nicotine from these formulations was very rapid (i.e. less than 10 min was required to reach plasma peaks) and showed substantially sustained plasma nicotine levels compared to saline solutions of NB and NS, and previously reported nasal nicotine sprays. The AUC values from the proliposomes and MP were comparable to those from the saline solutions of NB and NS. However, the mean residence time (MRT) and plasma half-life (T(1/2beta)) of nicotine in the present study were much larger than those from the saline solutions. Thus, a prolonged delivery of nicotine to systemic circulation via the application of proliposomes or MP intranasally appears feasible. NB-proliposomes exhibited the best characteristics in terms of the area under the plasma concentration (AUC), MRT and T(1/2beta) of nicotine, which was followed by NS-proliposomes and MP. Retarded conversion of proliposomes and MP to liposomal emulsions and solution in the nasal cavity seems responsible, in part, for the sustained plasma nicotine concentrations, since the emulsions and solution yielded very short MRT and T(1/2beta) of nicotine. In addition, reduced metabolism to cotinine from the proliposomes and MP was apparently responsible for the sustained plasma nicotine levels. These dosage forms of nicotine appear to circumvent some of the shortcomings of transdermal patches (i.e. long T(max)) and nasal sprays (i.e. short T(1/2beta) and physicochemical instability).

Activation of caspase cascades in Korean mistletoe (Viscum album var. coloratum) lectin-II-induced apoptosis of human myeloleukemic U937 cells

Mistletoe lectins are of high biological activity and exert cytotoxic effects. We have previously shown that Korean mistletoe, Viscum album var. coloratum, lectin-II specifically induces apoptotic cell death in cancer cells, not normal lymphocytes. The destructive mechanism by mistletoe lectins on tumor cells was mediated by activation of c-JUN N-terminal kinase (JNK)/stress-activated protein kinase. Herein, we investigated the involvement of caspase cascade and its proteolytic cleavage effects on biosubstrates of human myeloleukemic U937 cells by D-galactoside and N-acetyl-galactosamine-specific Korean mistletoe lectin-II. Mistletoe lectin-II induced ladder pattern DNA fragmentation and activation of caspase-3, -8, and -9 of U937 cells, but not caspase-1 protease, in a time- and dose-dependent manner. Consistent with catalytic activation of protease, both poly(ADP-ribose) polymerase (PARP) and protein kinase C-delta (PKC-delta) are also cleaved in mistletoe lectin-II-treated U937 cells. An inhibitor of caspase-3-like protease, DEVD-CHO peptide, significantly inhibited mistletoe lectin-II-induced apoptosis, PARP cleavage, and fragmentation of DNA. These results provide the evidence that Korean mistletoe lectin-II induces apoptotic death of U937 cells via activation of caspase cascades.

Cyclic adenosine monophosphate inhibits ursolic acid-induced apoptosis via activation of protein kinase A in human leukaemic HL-60 cells

This study was designed to investigate the effect of cAMP on ursolic acid-induced apoptosis of HL-60 cells. Ursolic acid decreased the viability of the cells in a dose-dependent manner, which was revealed as an apototic process characterized by ladder-pattern DNA fragmentation in agarose gel electrophoresis and segmented nuclei in DAPI-sulpharhodamin 101 staining. Ursolic acid-induced apoptosis of the cells was markedly inhibited by the addition of cAMP-elevating agents including DB-cAMP, CPT-cAMP, 8-Br-cAMP and forskolin. These results were further evidenced by the fact that inhibitors of cAMP-dependent protein kinase including H89 and KT5720 completely inhibited the cAMP-mediated rescue of HL-60 cells from ursolic acid-induced apoptosis. In addition, differentiating agents of the cells such as dimethyl sulfoxide and retinoic acid did not affect the ursolic acid-induced apoptosis of HL-60 cells. These results suggest that signaling pathway of cAMP-dependent activation of protein kinase A may affect the responsiveness of tumor cells upon ursolic acid.

Pharmacokinetics and urinary excretion of DW116, a new fluoroquinolone antibacterial agent, in humans as a phase I study

Pharmacokinetics and urinary excretion of the new fluoroquinolone antibacterial agent DW116 [1-(5-fluoro-2-pyridyl)-6-fluoro-7-(4-methyl-1-piperazynyl)-1, 4-dihydro-4-oxoquinolone-3-carboxylic acid, hydrochloride] following oral administration (200, 400, 600 mg) were studied in humans as a phase I study. The plasma concentration of DW116 declined monoexponentially with a half-life range of 16-22 hr. The area under the curve (AUC) and Cmax increased proportionally as the dose increased. The T1/2 and mean residence time (MRT) (28.3-30.9 hr) were independent of dose. The Tmax appeared within 3 hr (0.9-2.7 hr) after drug administration. The Ka ranged from 1.3 to 4.1 (hr-1). The plasma half-life was much longer, and Cmax was higher by about two- to three-fold than conventional fluoroquinolones. Urinary recovery of DW116 was 29.6-61.6% of the dose. The maximum excretion rate appeared within 4 hr and decreased continuously after drug administration. A urinary metabolite was not detected in the urine extract obtained before and after hydrolysis by beta-glucuronidase (from Escherichia coli); this was different from other fluoroquinolone antibacterial agents. Poor metabolism in the kidney may contribute to the good oral bioavailability, but due to the low recovery (< 60%) in urine, it is possible that DW116 is metabolized in the liver or other organs.

Simultaneous GC-MS determination of nicotine and cotinine in plasma for the pharmacokinetic characterization of nicotine in rats

A gas liquid chromatography/mass spectrometry assay method was developed for the simultaneous determination of nicotine and its major metabolite, cotinine, in rat plasma. Of particular interest was improving the low and variable extraction recovery for the parent drug and the metabolite. In addition, the feasibility of this assay method for pharmacokinetic studies of nicotine and cotinine after intravenous (i.v.), oral, and intraperitoneal (i.p.) administration of 1 mg kg(-1) of nicotine was tested. The low (30 and 48% for nicotine and cotinine, respectively) and variable (25 and 22% coefficient of variation for nicotine and cotinine, respectively) extraction recovery for nicotine and cotinine into dichloromethane was significantly improved by the addition of NaCl to the plasma. As a result, the recoveries for nicotine and cotinine were improved to 68 and 65%, respectively. The coefficient of variation was less than 10% in the 50-500 ng ml(-1) range and less than 16.58% at 10 ng ml(-1) for both nicotine and cotinine, indicating that the reproducibility of the assay was also improved by the extraction procedure. When injected intravenously at a dose of 1 mg kg(-1), the temporal profile of plasma concentration for nicotine followed a bi-exponential decline. Moment analysis revealed that pharmacokinetic parameters for nicotine (i.e. Cl, 46.30 ml min(-1) kg(-1); Vss, 2.77 1 kg(-1)) was similar to those reported in studies using 14C-nicotine. Absolute bioavailabilities of nicotine for i.p. and oral administration were 87.0 and 80.4%, respectively. The concentration of the metabolite increased up to 4 h to reach Cmax after i.p. and oral administrations and then declined slowly with time. These results indicate that this convenient analytical procedure is readily applicable to pharmacokinetic studies of nicotine and cotinine involving small laboratory animals with a sensitivity comparable with that reported for studies using 14C-nicotine.

Identification of urinary metabolites of clemastine after oral administration to man

The metabolism of clemastine, 2-[2-[1-(4-chlorophenyl)-1-phenylethoxylethyl])-1-methylpyrrolidin e, has been studied in three adult male volunteers after a single oral dose of 20 mg as the fumarate. After enzymatic hydrolysis solvent extracts of urine were derivatized with N-methyl-N-trimethylsilyltrifluoroacetamide-ammonium iodide and analysed by gas chromatography-mass spectrometry. The structures of metabolites were determined on the basis of electron impact and chemical ionization mass spectra and the identities of some (e.g. carbinol, 4-chlorobenzophenone and 4-chlorophenylstyrene) were confirmed by use of authentic standards. The principal route of metabolism of clemastine in man involves direct oxidation, O-dealkylation (fission of the ether bond), aromatic hydroxylation, aliphatic oxidation, alcoholic dehydration, and then enzymatic hydrolysis. Of the total amount of metabolites excreted in the urine 35% was carbinol (metabolite M3, major metabolite), 15% was M1, 17% was M2, 11% was M4, 9% was M5, 8% was M6 and 5% was M7.

Nitric oxide inhibits c-Jun N-terminal kinase 2 (JNK2) via S-nitrosylation

S-nitrosylation by S-nitrosoglutathione (GSNO), a nitric oxide (NO) donor, suppresses the phosphotransferase activity of cJun N-terminal kinase 2 (JNK2)/stress activated protein kinase (SAPK) in dose- and time-dependent manners in vitro. JNK2 activity is significantly decreased at 10 microM of GSNO, which is dramatically reversed by adding 10 mM of DTT. Reduced form of glutathione protects the GSNO-induced suppression of JNK2 activation in a dose-dependent fashion. However, GSNO-treated Sek1 does not affect the JNK2 activity of phosphotransferation toward c-Jun N-terminal1-79 protein. These results indicate that NO may exert a regulatory role of JNK2 activity by S-nitrosylation of the protein in apoptotic signaling pathway. Suppression of JNK2 phosphotransferase activity by NO is also supported by the observation that NO plays an important anti-apoptotic roles in heptocytes, splenocytes, eosinophils and B lymphocytes.

Metabolic disposition of the new fluoroquinolone antibacterial agent DW116 in rats

The metabolic disposition of the new fluoroquinolone antibacterial agent DW116 has been studied in Sprague-Dawley rats. The compound was absorbed well and demonstrated excellent oral bioavailability. The plasma kinetic profiles were characterized by monoexponential elimination with an elimination half life of 3-4 hr. The apparent mean total clearance (CL(T)) and the volume of distribution (V(SS)) ranged from 221 +/- 55 to 274 +/- 27 ml/hr/kg and 1.0+/-0.1 to 1.5+/-0.2 l/kg, respectively, and were independent of dose between 4 and 20 mg/kg levels. The renal (CL(R)) clearance was 64.5 ml/hr/kg and the biliary (CL(B)) clearance was 33.8 ml/hr/kg. The combined value accounted for approximately one-half of the total clearance, indicating that the remaining one-half of the administered dose was eliminated via hepatic clearance. The major metabolite excreted in the bile was identified as the glucuromide ester of parent drug using base-hydrolysis of the conjugate metabolite followed by co-HPLC with standard compound, 19F-NMR and LC-MS methods. The mean urinary recoveries of free and total (free plus glucuronide ester) DW116 were 28.6 +/- 2.7% and 36.4 +/- 1.8% of the administered dose and the corresponding biliary recoveries were 14.4 +/- 5.5% and 37.0 +/- 7.6%, respectively. The mass balance study after a single (100mg/kg) oral administration of 14C-DW116 indicated complete recovery of radioactivity over a 7-day period, accounting for approximately 60-70% in feces and 30-40% in urine. 14C-DW116 extensively distributed during a prolonged process into all tissues with a rather slower penetration into the brain, lung, and muscle. The compound also readily crossed the placenta and was transferred to the fetus.

Identification of urinary metabolites of pyrilamine after oral administration to man

1. The metabolism of pyrilamine, 2-[4-methoxybenzyl-(2-dimethylaminoethyl) amino] pyridine, was studied in adult male volunteers after a single oral dose of 50 mg. 2. Solvent extracts of urine obtained with or without enzyme hydrolysis were analysed by gc/ms after derivatization with MSTFA/TMSCI (N-methyl-N-trimethylsilyl-trifluoroacetamide/trimethyl chlorosilane). The structure of metabolites were determined based on EI mass spectra and confirmed with those of authentic standards. 3. Conjugated metabolites identified in the urine were pyrilamine, O-desmethylpyrilamine, and ring hydroxylated derivatives of pyrilamine. O-desmethylpyrilamine was also detected in low abundance as a free form. 4. These metabolites observed in human urine were quite different from those previously reported in rat.