Both cardiovascular and cerebrovascular events are decreased following long-term narrowband ultraviolet B phototherapy in patients with vitiligo: a propensity score matching analysis.

BACKGROUND: Systemic effects of long-term narrowband ultraviolet B (NB-UVB) phototherapy have not been well studied in vitiligo patients. An 11-year nationwide population-based retrospective cohort study was conducted using the Korean National Health Insurance claims database (2007-2017). OBJECTIVES: To investigate the effects of long-term NB-UVB phototherapy on the risk of cardiovascular and cerebrovascular events in vitiligo patients. METHODS: This study included vitiligo patients with ≥100 phototherapy sessions (phototherapy group, n = 3229) and <3 phototherapy sessions (no phototherapy group, n = 9687), in which covariables with age, sex, insurance type and comorbidities such as diabetes, hypertension and hyperlipidemia were matched by 1 : 3 propensity score matching. The outcomes of interest were cardiovascular (ischaemic heart disease and myocardial infarction) and cerebrovascular events (cerebrovascular infraction and haemorrhage). Cox proportional hazards models were used to assess the associations between NB-UVB phototherapy and each event. RESULTS: The risk of cardiovascular or cerebrovascular events was significantly decreased in the phototherapy group compared with the no phototherapy group [hazard ratio (HR) 0.637, 95% confidence interval (CI) 0.523-0.776]. Subgroup analysis revealed that the risk of cardiovascular (HR: 0.682, 95% CI: 0.495-0.940) and cerebrovascular events (HR: 0.601, 95% CI: 0.470-0.769) were significantly lower in the phototherapy group than the no phototherapy group, respectively. CONCLUSIONS: Our findings suggest that long-term NB-UVB phototherapy could decrease the risk of cardiovascular and cerebrovascular events in patients with vitiligo.

Digital health screening tool for identification of elder mistreatment.

PURPOSE: It is estimated that 15.7% of people aged 60 years and older were subjected to some form of Elder Mistreatment (EM) globally (Yon et al., 2017). In the USA, as many as 1 in 24 EM cases are left unidentified by professionals, with a 300% increased mortality risk for older adults who do not receive help (National Center on Elder Abuse, n.d.; Dong, 2009). Current methods of screening tend to miss less obvious signs of EM and may discourage older adults from disclosing EM, due to either a lack of understanding of what constitutes mistreatment or fear of retaliation from the perpetrator. METHOD: Our approach shifts the focus of EM identification to the older adults themselves through an automated tablet-based tool. The Virtual cOaching in making Informed Choices on Elder Mistreatment Self-Disclosure (VOICES) tool includes various multimedia components such as videos, audio, and animations designed to educate and enhance screening. Patients screened as positive are guided through a Brief Negotiated Interview (BNI) utilizing motivational interviewing to assist in self-identification (recognize that they are experiencing elder mistreatment) or self-disclosure (inform others about their elder mistreatment experiences). During tool development, we conducted a qualitative study to evaluate the perceived value and likelihood of adopting a tablet-based approach to facilitate screening and self-disclosure of EM in the ED. We held 3 focus groups with stakeholders, including 24 adults 60 years or over, 2 social workers, 2 caregivers, and 2 ED clinicians. We used the findings from the focus groups and User-Centered Design approach (UCD) to develop the tablet-based screening tool. Once the tool was ready, we tested its usability and acceptability with 14 older adults. RESULTS AND DISCUSSION: Focus group participants supported use of a tablet-based tool to screen for EM, indicating that digital screening benefits from feelings of privacy and anonymity. On a 7-point Likert scale ranging from "1=Very Comfortable" to "7=Very Uncomfortable", older adults scored 2.8 on average for whether they would feel comfortable using a tablet device to screen for EM. Prominent suggestions made by older adults included using a female voice for the tool narrator, larger font size, more multimedia, headphones for privacy; and having someone available during screening for assistance if needed. Participants indicated that it is difficult for older adults experiencing EM to ask for help and that any type of mistreatment screening would be helpful. They also highlighted the need to explain community resources available to older adults once EM is disclosed, especially resources offering help to the caregiver. Participants of the usability evaluation rated the tool a mean score of 86.6 (median= 88.8, iQR =18.1) on the System Usability Scale (SUS), far above the benchmark SUS score of 68, which indicates that the system is "good" or "acceptable" (Bangor et al., 2008). Shifting the focus from the provider to the older adult may encourage self-disclosure of EM by addressing major barriers to traditional screening processes. In summary, this study supported the use of self-administered automated tablet-based screening for EM. Participants generally believed that the use of digital health tools to facilitate the screening process would be beneficial in the ED setting.

Clinical implication of extended-spectrum cephalosporin nonsusceptibility in Streptococcus pneumoniae meningitis.

The clinical implication of extended-spectrum cephalosporin (ESC) resistance has been unclear in patients with Streptococcus pneumoniae meningitis (SPM). We collected the clinical data of 120 patients with SPM in 12 hospitals of the Republic of Korea. The clinical characteristics and outcomes of 23 ESC-nonsusceptible SPM episodes were compared to those of 97 ESC-susceptible episodes. Hospital acquisition, presence of other foci of pneumococcal infection, septic shock at initial presentation, or concomitant bacteremia were more commonly observed in ESC-nonsusceptible than ESC-susceptible SPM. Empiric antimicrobial therapy with vancomycin and ESC combination was very common in both groups. Although there was a tendency towards higher early fatality in ESC-nonsusceptible SPM (3-day mortality; 17.4 % vs. 4.4 %, p = 0.05), in-hospital mortality (26.1 % vs. 20.9 %, p = 0.59) and median length of hospital stay (20 days vs. 24 days, p = 0.34) did not differ between ESC-nonsusceptible and ESC-susceptible SPM.

Acquisition of extensive drug-resistant Pseudomonas aeruginosa among hospitalized patients: risk factors and resistance mechanisms to carbapenems.

Extensive drug-resistant Pseudomonas aeruginosa (XDRPA) strains, defined as resistant to all available antipseudomonal antibiotics, have been reported recently. This study aimed to investigate the risk factors for XDRPA acquisition by patients and the resistance mechanisms to carbapenems. From June to November 2007, XDRPA isolates were collected from patients in eight tertiary care hospitals. A case-control study was performed to determine factors associated with XDRPA acquisition. EDTA-imipenem disc synergy tests, and polymerase chain reaction amplification and sequencing were performed to detect the presence of metallo-ß-lactamases (MBLs). Risk factor analysis was performed for 33 patients. Mechanical ventilation [odds ratio (OR) 8.2, 95% confidence interval (CI) 1.3-52.2; P = 0.026] and APACHE II score (OR 1.2, 95% CI 1.0-1.3; P = 0.007) were identified as independent risk factors for XDRPA acquisition. Pulsed-field gel electrophoresis of XDRPA identified clonal epidemic isolates co-existing with sporadic isolates. Eight of 43 (19%) XDRPA isolates were shown to produce MBLs; four produced VIM-2 and four produced IMP-6. This study suggests a major role for mechanical ventilation in XDRPA acquisition. Moreover, pulsed-field gel electrophoresis identified a clonal epidemic within hospitals. Taken together, these results suggest that patient-to-patient transmission contributes to XDRPA acquisition in Korea.

Disposition of GDC-0879, a B-RAF kinase inhibitor in preclinical species.

1. The pharmacokinetics and disposition of GDC-0879, a small molecule B-RAF kinase inhibitor, was characterized in mouse, rat, dog, and monkey. 2. In mouse and monkey, clearance (CL) of GDC-0879 was moderate (18.7-24.3 and 14.5 +/- 2.1 ml min(-1) kg(-1), respectively), low in dog (5.84 +/- 1.06 ml min(-1) kg(-1)) and high in rat (86.9 +/- 14.2 ml min(-1) kg(-1)). The volume of distribution across species ranged from 0.49 to 1.9 l kg(-1). Mean terminal half-life values ranged from 0.28 h in rats to 2.97 h in dogs. Absolute oral bioavailability ranged from 18% in dog to 65% in mouse. 3. Plasma protein binding of GDC-0879 in mouse, rat, dog, monkey, and humans ranged from 68.8% to 81.9%. 4. In dog, the major ketone metabolite (G-030748) of GDC-0879 appeared to be formation rate-limited. 5. Based on assessment in dogs, the absorption of GDC-0879 appeared to be sensitive to changes in gut pH, food and salt form (solubililty), with approximately three- to four-fold change in areas under the curve (AUCs) observed.

Prevalence, microbiology, and clinical characteristics of extended-spectrum beta-lactamase-producing Enterobacter spp., Serratia marcescens, Citrobacter freundii, and Morganella morganii in Korea.

We examined the prevalence and characteristics of extended-spectrum beta-lactamase (ESBL)-producing clinical isolates among Enterobacter spp., Serratia marcescens, Citrobacter freundii, and Morganella morganii, and evaluated screening criteria, clinical characteristics and outcomes of infections caused by ESBL-producing organisms. Between January and June 2005, a total of 493 nonduplicate consecutive isolates were collected at Asan Medical Center, a 2,300-bed tertiary hospital in Seoul, Republic of Korea. Fifty isolates (10.1%) were positive for phenotypical ESBL-test. The positive rate of phenotypical ESBL-test in Enterobacter spp., S. marcescens, C. freundii, and M. morganii was 12.8%, 12.4%, 4.9%, and 0% respectively. SHV-12 (18 isolates), CTX-M-9 (17 isolates), and TEM-52 (five isolates) were the most prevalent ESBL types. The ESBL in 17 strains could not be identified. As an ESBL screening criterion, the cefepime MIC >or=1 microg/ml had the highest sensitivity (0.84) and specificity (0.87). Half of the ESBL-producing isolates (25/50) were judged as pathogens. Cholangitis (ten cases), and pneumonia (six cases) were the most common infections. The overall mortality was 12.0%.

Regional radiotherapy may improve outcomes in patients with early stage breast cancer undergoing breast conservation therapy.

BACKGROUND: Breast conservation therapy (BCT) is recommended as standard management of early breast cancer. The aim of this study was to retrospectively evaluate the results of BCT to identify prognostic factors predictive of treatment outcomes. PATIENTS AND METHODS: Four hundred and ninety-eight eligible women with unilateral stage I-II breast cancer who had undergone BCT were analyzed. RESULTS: The cumulative incidence of local recurrence (LR) was 1.9% and 3.7% at 3- and 5-years respectively. The 5-year disease-free, cancer-specific, and overall survival (DFS, CSS, OS) were 80.0%, 87.3% and 85.4% respectively. Significant independent predictors for LR included young age and absence of chemotherapy. Regional nodal radiotherapy was significantly associated with improved DFS and OS. CONCLUSION: Our results confirmed the efficacy of BCT in the treatment of early breast cancer and indicated that inclusion of regional nodal areas within the radiotherapy field might be beneficial in the BCT setting, particularly for patients with adverse risk features.

Disposition of CP-671, 305, a selective phosphodiesterase 4 inhibitor in preclinical species.

1. The disposition of (+)-2-[4-({[2-(benzo[1,3] dioxol-5-yloxy)-pyridine-3-carbonyl]-amino)-methyl)-3-fluoro-phenoxyl-propionic acid (CP-671,305), a potent and selective inhibitor of phosphodiesterase 4 (subtype D), was characterized in several animal species in support of its selection for preclinical safety studies and potential clinical development. 2. CP-671,305 demonstrates generally favourable pharmacokinetic properties in all species examined. Systemic plasma clearance after intravenous administration was low in Sprague-Dawley rats (9.60+/-1.16 ml min(-1) kg(-1)), beagle dogs (2.90+/-0.81 ml min(-1) kg(-1)) and cynomolgus monkeys (2.94+/-0.87ml min(-1) kg(-1)) resulting in plasma half-lives > 5 h. Moderate to high bioavailability in rats (43-80%), dogs (45%) and monkeys (26%) was observed after oral dosing. In rats, oral pharmacokinetics were dose dependent over the dose range studied (10 and 25 mgkg(-1)). 3. CP-671,305 was > 97% bound to plasma proteins in rat, dog, monkey and human. 4. The principal route of clearance of CP-671,305 in rats and dogs was by renal and biliary excretion of unchanged drug. This finding was consistent with CP-671,305 resistance towards metabolism in hepatocytes and NADPH-supplemented liver microsomes from preclinical species and human. 5. CP-671,305 did not exhibit competitive inhibition of the five major cytochrome P450 enzymes, namely CYP1A2, 2C9, 2C19, 2D6 and 3A4 (IC50's > 50 microM). Likewise, no time-dependent inactivation of the five major cytochrome P450 enzymes was discernible with CP-671,305. 6. Overall, the results indicate that the absorption, distribution, metabolism and excretion (ADME) profile of CP-671,305 is relatively consistent across preclinical species and predict potentially favourable pharmacokinetic properties in humans, supporting its selection for toxicity/safety assessment studies and possible investigations in humans.

Identification of functionally variant MDR1 alleles among European Americans and African Americans.

MDR1 (P-glycoprotein) is an important factor in the disposition of many drugs, and the involved processes often exhibit considerable interindividual variability that may be genetically determined. Single-strand conformational polymorphism analysis and direct sequencing of exonic MDR1 deoxyribonucleic acid from 37 healthy European American and 23 healthy African American subjects identified 10 single nucleotide polymorphisms (SNPs), including 6 nonsynonymous variants, occurring in various allelic combinations. Population frequencies of the 15 identified alleles varied according to racial background. Two synonymous SNPs (C1236T in exon 12 and C3435T in exon 26) and a nonsynonymous SNP (G2677T, Ala893Ser) in exon 21 were found to be linked (MDR1*2 ) and occurred in 62% of European Americans and 13% of African Americans. In vitro expression of MDR1 encoding Ala893 (MDR1*1 ) or a site-directed Ser893 mutation (MDR1*2 ) indicated enhanced efflux of digoxin by cells expressing the MDR1-Ser893 variant. In vivo functional relevance of this SNP was assessed with the known P-glycoprotein drug substrate fexofenadine as a probe of the transporter's activity. In humans, MDR1*1 and MDR1*2 variants were associated with differences in fexofenadine levels, consistent with the in vitro data, with the area under the plasma level-time curve being almost 40% greater in the *1/*1 genotype compared with the *2/*2 and the *1/*2 heterozygotes having an intermediate value, suggesting enhanced in vivo P-glycoprotein activity among subjects with the MDR1*2 allele. Thus allelic variation in MDR1 is more common than previously recognized and involves multiple SNPs whose allelic frequencies vary between populations, and some of these SNPs are associated with altered P-glycoprotein function.

In vivo inhibition of human CYP1A2 activity by oltipraz.

PURPOSE: Oltipraz is currently undergoing clinical evaluation as a cancer chemopreventive agent, especially with respect to aflatoxin-associated hepatocarcinogenesis. The agent's ability to induce phase II xenobiotic enzymes that detoxify the ultimate carcinogen formed in vivo is thought to be an important mechanism by which disease risk may be attenuated. However, an additional mechanism could be a reduction in the activation of environmental procarcinogens by certain cytochrome P450 (CYP) isoforms. This hypothesis was tested with respect to CYP1A2, by using the clearance of caffeine by N-demethylation as a phenotypic trait measurement of the isoform's catalytic activity. METHODS: Subjects received a single oral dose of caffeine (200 mg) on five separate occasions: on the day prior to oltipraz administration (day 0), 2 h after the first (day 1) of eight daily oral doses of oltipraz (125 mg) and 2 h after the last dose (day 8). In addition, CYP1A2 activity was also measured 2 and 14 days (days 10 and 22, respectively) after discontinuation of oltipraz administration. Plasma concentrations of caffeine and its N-demethylated metabolite, paraxanthine, over 24 h after drug administration, were determined by HPLC. RESULTS: A single 125-mg dose of oltipraz markedly reduced CYP1A2 activity by 75 +/- 13% in nine healthy subjects, resulting in a higher caffeine plasma level and prolongation of the in vivo probe's elimination half-life. Daily administration of 125 mg oltipraz for 8 days resulted in further inhibition so that only 19 +/- 13% of the original baseline level of activity was present. However, 2 days after discontinuation of oltipraz treatment, CYP1A2 activity had returned to 66 +/- 33% of its original level and complete recovery was achieved within 14 days of the chemopreventive agent being stopped. CONCLUSIONS: These results demonstrate that oltipraz is a potent, in vivo inhibitor of CYP1A2 in humans and, because this isoform is importantly involved in procarcinogen activation, they also indicate that such inhibition probably contributes to oltipraz's cancer-chemopreventive effect. In addition, the findings also suggest the likelihood of significant drug interactions between oltipraz and drugs whose metabolism is mediated by CYP1A2.

Arthroscopic treatment for localized pigmented villonodular synovitis of the knee.

This study investigated 11 patients with localized pigmented villonodular synovitis of the knee that was diagnosed and treated by arthroscopic technique. There were six male and five female patients between the ages of 15 and 59 years (mean, 34.6 years). Seven patients reported extension limitation without joint line tenderness. Four of the 11 patients had a history of trauma before the onset of knee symptoms. All patients were treated by arthroscopic resection with partial synovectomy. The most common involved site was the anteromedial synovium near the anterior horn of the medial meniscus (five patients). The remaining cases were located in the anterior fat pad (two patients), suprapatellar pouch, posteromedial compartment, medial gutter, and the anterior horn of the lateral meniscus. Nine patients had one mass, and the remaining patients each had two or three masses. There was no evidence of recurrence at followup for an average of 29.9 months (range, 24-48 months). Arthroscopy is effective in the diagnosis of localized pigmented villonodular synovitis with minimal morbidity, and complete arthroscopic excision can be considered the definitive treatment for localized pigmented villonodular synovitis.

Pharmacological inhibition of P-glycoprotein transport enhances the distribution of HIV-1 protease inhibitors into brain and testes.

HIV protease inhibitors have proven remarkably effective in treating HIV-1 infection. However, some tissues such as the brain and testes (sanctuary sites) are possibly protected from exposure to HIV protease inhibitors due to drug entry being limited by the membrane efflux transporter P-glycoprotein, located in the capillary endothelium. Intravenous administration of the novel and potent P-glycoprotein inhibitor LY-335979 to mice (1-50 mg/kg) increased brain and testes concentration of [(14)C]nelfinavir, up to 37- and 4-fold, respectively, in a dose-dependent fashion. Similar effects in brain levels were also observed with (14)C-labeled amprenavir, indinavir, and saquinavir. Because [(14)C]nelfinavir plasma drug levels were only modestly increased by LY-335979, the increase in brain/plasma and testes/plasma ratios of 14- to 17- and 2- to 5-fold, respectively, was due to increased tissue penetration. Less potent P-glycoprotein inhibitors like valspodar (PSC-833), cyclosporin A, and ketoconazole, as well as quinidine and verapamil, had modest or little effect on brain/plasma ratios but increased plasma nelfinavir concentrations due to inhibition of CYP3A-mediated metabolism. Collectively, these findings provide "proof-of-concept" for increasing HIV protease inhibitor distribution into pharmacologic sanctuary sites by targeted inhibition of P-glycoprotein using selective and potent agents and suggest a new therapeutic strategy to reduce HIV-1 viral replication.

Effect of cirrhosis on sulphation by the isolated perfused rat liver.

BACKGROUND/AIMS: There is evidence to suggest that not all pathways of drug metabolism are similarly affected in cirrhosis. The effect of cirrhosis on drug oxidation and glucuronidation has been extensively investigated but little is known of the effect of cirrhosis on drug sulphation. The aim of this study was to investigate the effect of cirrhosis on sulphation. METHODS: We investigated the effect of cirrhosis on p-nitrophenol sulphation and compared this with the effect of cirrhosis on p-nitrophenol glucuronidation as well as on d-propranolol oxidation simultaneously in the single-pass isolated perfused rat liver. The perfusate contained added inorganic sulphate to maximise production of p-nitrophenol sulphate. RESULTS: About 77% and 59% of p-nitrophenol was eliminated as the sulphate conjugate by the healthy (n=6) and cirrhotic (n=7) livers, respectively. Mean total p-nitrophenol clearance was decreased in cirrhosis (healthy: 18.5+/-0.2 vs. cirrhotic 15.3+/-4.0 ml/min; p<0.05). The decrease in total clearance of p-nitrophenol was due solely to the decrease in sulphate formation clearance, which was significantly decreased (healthy: 14.1+/-1.9 vs. cirrhotic: 9.27+/-3.33 ml/min; p<0.05). Mean glucuronide formation clearance (healthy: 5.11+/-0.94 vs cirrhotic: 5.79+/-0.85 ml/ min; p>0.05) was not significantly altered. Mean total propranolol clearance was decreased in cirrhosis (healthy: 19.9+/-0.1 vs. cirrhotics: 18.0+/-1.5 ml/min; p<0.05). CONCLUSIONS: We have shown that in cirrhosis there is significant impairment of drug oxidation and sulphation, whilst glucuronidation is spared. The decreased sulphation of p-nitrophenol was most likely due to a decrease in phenol sulphotransferase and/or decrease in cofactor synthesis.

Cloning and characterization of human inducible nitric oxide synthase splice variants: a domain, encoded by exons 8 and 9, is critical for dimerization.

The inducible nitric oxide synthase (iNOS) contains an amino-terminal oxygenase domain, a carboxy-terminal reductase domain, and an intervening calmodulin-binding region. For the synthesis of nitric oxide (NO), iNOS is active as a homodimer. The human iNOS mRNA is subject to alternative splicing, including deletion of exons 8 and 9 that encode amino acids 242-335 of the oxygenase domain. In this study, iNOS8(-)9(-) and full-length iNOS (iNOSFL) were cloned from bronchial epithelial cells. Expression of iNOS8(-)9(-) in 293 cell line resulted in generation of iNOS8(-)9(-) mRNA and protein but did not lead to NO production. In contrast to iNOSFL, iNOS8(-)9(-) did not form dimers. Similar to iNOSFL, iNOS8(-)9(-) exhibited NADPH-diaphorase activity and contained tightly bound calmodulin, indicating that the reductase and calmodulin-binding domains were functional. To identify sequences in exons 8 and 9 that are critical for dimerization, iNOSFL was used to construct 12 mutants, each with deletion of eight residues in the region encoded by exons 8 and 9. In addition, two "control" iNOS deletion mutants were synthesized, lacking either residues 45-52 of the oxygenase domain or residues 1131-1138 of the reductase domain. Whereas both control deletion mutants generated NO and formed dimers, none of the 12 other mutants formed dimers or generated NO. The region encoded by exons 8 and 9 is critical for iNOS dimer formation and NO production but not for reductase activity. This region could be a potential target for therapeutic interventions aimed at inhibiting iNOS dimerization and hence NO synthesis.

Chloramphenicol in children: dose, plasma levels and clinical effects.

Despite concerns about adverse effects, chloramphenicol (CMC) continues to be used in certain situations and, due to its low therapeutic index and variable pharmacokinetics, therapeutic drug monitoring (TDM) is often recommended. At our centre, CMC finds applications in typhoid and meningitis and TDM is routinely performed. Elsewhere in Malaysia, however, CMC is used without TDM. We therefore decided to evaluate our TDM for CMC in relation to its roles in CMC therapy in children, who constitute most of our patients. Our objective was also to develop strategies to improve our TDM for CMC use. Data were collected from 168 children given CMC for various indications and monitored by the TDM service. Plasma CMC was determined by HPLC and used to adjust doses to maintain concentrations within a range of 10-25 micrograms/ml. Outcomes measured included daily temperatures and haematological indices. Daily doses and plasma CMC varied greatly. Doses averaged 40.5 mg/kg for neonates and 75.5 for older children. Average peak concentrations were therapeutic in 60% and trough in 42%. Average duration of fever was 6.3 days and it was unaffected by plasma CMC. Typhoid was eradicated in 97% but nine children with other diagnoses died. Side-effects were confined to mild reversible haematological abnormalities which developed in 11% of children at plasma concentrations which tended to be high. We conclude that CMC remains useful in children with typhoid. Its use for other indications, however, should be reviewed. Routine TDM for CMC is probably not warranted, at least until a clearer role is defined by well designed prospective studies.

Increased sensitivity of propranolol clearance to reduced oxygen delivery in the isolated perfused cirrhotic rat liver.

BACKGROUND & AIMS: Capillarization of the sinusoids in cirrhosis is proposed to reduce oxygen availability to the hepatocyte, resulting in the patterns of altered drug metabolism observed in cirrhosis. If this were true, drug metabolism in cirrhotic livers would be expected to be more sensitive to reduced oxygen delivery than in noncirrhotic livers. The aim of this study was to compare the sensitivity of propranolol clearance with reduced oxygen delivery in isolated perfused livers from healthy and cirrhotic rats. METHODS: Propranolol clearance was measured at steady state in 5 normal and 5 cirrhotic weight-matched perfused rat livers under single-pass conditions with normal oxygen delivery (mean, 71.5 mumol/min) and with graded reductions in oxygen delivery (range, 58.1-18.8 mumol/min). RESULTS: In noncirrhotic livers, propranolol clearance was independent of oxygen supply for the oxygen delivery range of 73-45 mumol/min but decreased with further reductions in oxygen supply. In cirrhotic livers, propranolol clearance decreased linearly (r2 = 0.92; P < 0.005) for the entire oxygen delivery range (73.4-18.8 mumol/min). CONCLUSIONS: The increased sensitivity of propranolol clearance in perfused cirrhotic livers to reductions in oxygen delivery is consistent with impaired oxygen delivery to hepatocytes in cirrhosis. These novel findings potentially hold implications for clinical management of patients with cirrhosis.

Alternative splicing of human inducible nitric-oxide synthase mRNA. tissue-specific regulation and induction by cytokines.

Human inducible nitric-oxide synthase (iNOS) is responsible for nitric oxide synthesis in response to inflammatory mediators. The human iNOS gene, containing 26 exons, encodes a protein of 131 kDa. This study was aimed at investigating the presence of alternative splicing of human iNOS mRNA. Total RNA from human alveolar macrophages, nasal and bronchial epithelial cells, and several human tissues was transcribed to cDNA and analyzed using polymerase chain reaction with specific primers for segmental analysis of the iNOS gene. Four sites of alternative splicing were identified by sequence analysis; these included deletion of: (i) exon 5; (ii) exons 8 and 9; (iii) exons 9, 10, and 11; and (iv) exons 15 and 16. The deduced amino acid sequences of the novel iNOS cDNAs predict one truncated protein (resulting from exon 5 deletion) and three iNOS proteins with in-frame deletions. Southern analyses of polymerase chain reaction products were consistent with tissue-specific regulation of alternative splicing. In cultured cells, iNOS induction by cytokines and lipopolysaccharide was associated with an increase in alternatively spliced mRNA transcripts. Because iNOS is active as a dimer, the novel forms of alternatively spliced iNOS may be involved in regulation of nitric oxide synthesis.