Safety and Pharmacokinetics of Glecaprevir/Pibrentasvir in Adults With Chronic Genotype 1-6 Hepatitis C Virus Infections and Compensated Liver Disease

Background

Untreated, chronic hepatitis C virus (HCV) infection may lead to progressive liver damage, which can be mitigated by successful treatment. This integrated analysis reports the safety, efficacy, and pharmacokinetics (PK) of the ribavirin-free, direct-acting, antiviral, fixed-dose combination of glecaprevir/pibrentasvir (G/P) in patients with chronic HCV genotype 1–6 infections and compensated liver disease, including patients with chronic kidney disease stages 4 or 5 (CKD 4/5).

Methods

Data from 9 Phase II and III clinical trials, assessing the efficacy and safety of G/P treatment for 8–16 weeks, were included. The presence of cirrhosis was determined at screening using a liver biopsy, transient elastography, or serum biomarkers. The objectives were to evaluate safety, the rate of sustained virologic response at post-treatment week 12 (SVR₁₂), and steady-state PK by cirrhosis status.

Results

Among 2369 patients, 308 (13%) were Child-Pugh Class A, including 20 with CKD 4/5. Overall, <1% of patients experienced an adverse event (AE) that led to G/P discontinuation or G/P-related serious AEs (SAEs). The most common AEs were headache and fatigue, occurring at similar frequencies with and without cirrhosis. SAEs were more common in patients with CKD 4/5, but all were unrelated to G/P. There were no cases of drug-induced liver injury or clinically relevant hepatic decompensation. SVR₁₂ rates were 96.4% (297/308) with compensated cirrhosis and 97.5% (2010/2061) without cirrhosis. PK analysis demonstrated a 2.2-fold increase in glecaprevir exposure, but not pibrentasvir exposure, in patients with compensated cirrhosis.

Conclusions

G/P was safe and efficacious in patients with compensated liver disease, including those with CKD 4/5.

Clinical Trials Registration

NCT02243280, NCT02243293, NCT02604017, NCT02640482, NCT02640157, NCT02636595, NCT02642432, NCT02651194, and NCT02446717

A259 HIGH-FAT/HIGH-CHOLESTEROL DIETS PREDISPOSE THE HOST TO EXACERBATED ENTERIC INFECTIONS

Background

High-fat/high-cholesterol diets are a well established risk factor for cardiovascular and metabolic diseases, given their propensity to trigger perturbations ranging from altering whole body lipid profile to the induction of intestinal dysbiosis. However much less is known about their effects on the host’s susceptibility to enteric infections.

Aims

To determine the effects of high-fat/high-cholesterol diets over the host’s susceptibility to enteric bacterial infections and identify the underlying molecular mechanisms.

Methods

C57BL/6 mice were given two different high-fat/high-cholesterol diets; HFHC (40% kcal fat, 1.25% cholesterol) or HFHCC (40% kcal fat, 1.25% cholesterol, 0.5% sodium cholate) and a control, normal diet (ND, 10% kcal fat, 0% cholesterol, 0% sodium cholate). After four weeks of administration, animals were euthanized and colonic tissue samples taken for histology, immunofluorescence, gene expression analyses, total protein lysates and microbiome sequencing (16S). A separated group of animals was gavaged with FITC-dextran to measure intestinal permeability. Mice fed with the diets for three weeks were infected with ~5x108 cfu of Citrobacter rodentium DBS100/StrpR by oral gavage, and kept on the corresponding diets after the infections. Bacterial shedding in the feces was followed for up to 30 days after infection.

Results

Administration of the HFHC and HFHCC diets caused an increase in intestinal permeability. Colonic sections stained with H&E and alcian blue evidenced a decreased in the number of mucin-filled goblet cells and a thinner mucus layer, suggesting a defect in the assembly and/or stability of the mucus layer. Expression analyses revealed a drop in the mRNA levels of Muc1 and Muc2, suggesting reduced mucin production. The concentration of IgA was slightly reduced in colon lysates and the transcript levels of the antimicrobial peptide genes Ang4, Leap2 and Cramp were also significantly reduced. Immunofluorescent microscopy showed that goblet cell granules of HFHC- and HFHCC-fed mice were devoid of Relmβ and Tff3, indicating defective production of those two factors critical for intestinal epithelial defense and homeostasis. Collectively, our results suggest that HFHC and HFHCC diets induce differentiation and functional defects in goblet cells. Fecal shedding of C. rodentium showed an increased bacterial burden in HFHC- and HFHCC-fed animals, indicating a more aggressive bacterial infection, accompanied by increased epithelial damage.

Conclusions

Consumption of high-fat/high cholesterol diets perturb the colonic homeostasis and alter intestinal defenses and the integrity of the intestinal barrier, predisposing the host to a higher susceptibility to enteric infections.

Funding Agencies

CIHRNSERC

Universal and Non-universal Features of Musical Pitch Perception Revealed by Singing

Musical pitch perception is argued to result from nonmusical biological constraints and thus to have similar characteristics across cultures, but its universality remains unclear. We probed pitch representations in residents of the Bolivian Amazon-the Tsimane', who live in relative isolation from Western culture-as well as US musicians and non-musicians. Participants sang back tone sequences presented in different frequency ranges. Sung responses of Amazonian and US participants approximately replicated heard intervals on a logarithmic scale, even for tones outside the singing range. Moreover, Amazonian and US reproductions both deteriorated for high-frequency tones even though they were fully audible. But whereas US participants tended to reproduce notes an integer number of octaves above or below the heard tones, Amazonians did not, ignoring the note "chroma" (C, D, etc.). Chroma matching in US participants was more pronounced in US musicians than non-musicians, was not affected by feedback, and was correlated with similarity-based measures of octave equivalence as well as the ability to match the absolute f0 of a stimulus in the singing range. The results suggest the cross-cultural presence of logarithmic scales for pitch, and biological constraints on the limits of pitch, but indicate that octave equivalence may be culturally contingent, plausibly dependent on pitch representations that develop from experience with particular musical systems. VIDEO ABSTRACT.

Efficacy and safety of risankizumab in Japanese patients with moderate to severe plaque psoriasis: Results from the SustaIMM phase 2/3 trial

Risankizumab, a humanized immunoglobulin G1 monoclonal antibody, selectively inhibits interleukin‐23, a key cytokine in the pathogenesis of psoriasis, by binding to its p19 subunit. In SustaIMM (ClinicalTrials.gov/NCT03000075), a phase 2/3, double‐blinded, placebo‐controlled study, Japanese patients with moderate to severe plaque psoriasis (n = 171) were stratified by bodyweight and concomitant psoriatic arthritis and randomized 2:2:1:1 to 75 mg risankizumab, 150 mg risankizumab, placebo with cross‐over to 75 mg risankizumab and placebo with cross‐over to 150 mg risankizumab. Dosing was at weeks 0, 4, 16, 28 and 40, with placebo cross‐over to risankizumab at week 16. The primary end‐point was 90% or more improvement from baseline in Psoriasis Area and Severity Index (PASI‐90) at week 16 for risankizumab versus placebo. Missing data were imputed as non‐response. All primary and psoriasis‐related secondary end‐points were met for both risankizumab doses (P < 0.001). At week 16, PASI‐90 responses were significantly higher in patients receiving 75 mg (76%) or 150 mg (75%) risankizumab versus placebo (2%). Corresponding response rates were 86%, 93% and 10% for static Physician Global Assessment (sPGA) score of clear/almost clear; 90%, 95% and 9% for PASI‐75; and 22%, 33% and 0% for PASI‐100, with significantly higher responses for both risankizumab doses versus placebo. Through week 52, PASI and sPGA responses increased or were maintained and treatment‐emergent adverse events were comparable across treatment groups. Both doses of risankizumab were superior to placebo in treating patients with moderate to severe plaque psoriasis. The safety profile was consistent with previous risankizumab trials, with no new or unexpected safety findings.

Glecaprevir plus pibrentasvir for chronic hepatitis C virus genotype 1, 2, 4, 5, or 6 infection in adults with compensated cirrhosis (EXPEDITION-1): a single-arm, open-label, multicentre phase 3 trial

BACKGROUND

The once-daily, ribavirin-free, pangenotypic, direct-acting antiviral regimen, glecaprevir coformulated with pibrentasvir, has shown high rates of sustained virological response in phase 2 and 3 studies. We aimed to assess the efficacy and safety of 12 weeks of coformulated glecaprevir and pibrentasvir in patients with hepatitis C virus (HCV) infection and compensated cirrhosis.

METHODS

We did this single-arm, open-label, multicentre phase 3 study at 40 sites in Belgium, Canada, Germany, South Africa, Spain, and the USA. We enrolled patients aged 18 years or older with HCV genotype 1, 2, 4, 5, or 6 infection and compensated cirrhosis. Patients were either HCV treatment-naive or had not responded to treatment with interferon or pegylated interferon with or without ribavirin, or sofosbuvir plus ribavirin with or without pegylated interferon. Oral glecaprevir (300 mg) coformulated with pibrentasvir (120 mg) was administered once daily for 12 weeks. The primary efficacy endpoint was sustained virological response at post-treatment week 12 (HCV RNA <15 IU/mL). We assessed efficacy and safety in all patients who received at least one dose of study drug (intention-to-treat population). This study is registered with ClinicalTrials.gov, number NCT02642432.

FINDINGS

Between Dec 7, 2015, and May 4, 2016, we enrolled 146 patients with compensated cirrhosis, of whom 48 (33%) had genotype 1a HCV infection, 39 (27%) had genotype 1b infection, 34 (23%) had genotype 2 infection, 16 (11%) had genotype 4 infection, two (1%) had genotype 5 infection, and seven (5%) had genotype 6 infection. 12 weeks after treatment, 145 patients (99%, 95% CI 98-100) achieved sustained virological response, with one (1%) relapse at post-treatment week 8. We recorded 101 (69%) adverse events, of which 65 (64%) were mild. The most common adverse events were fatigue (n=28 [19%]) and headache (n=20 [14%]). 11 (8%) patients had serious adverse events, none of which were deemed related to study drugs. No patients had elevations in alanine aminotransferase and no patients prematurely discontinued treatment because of adverse events.

INTERPRETATION

Our results show that 99% of patients treated with once-daily glecaprevir plus pibrentasvir achieved a sustained virological response at 12 weeks. Furthermore, this drug regimen had a favourable safety profile in previously treated or untreated patients with chronic HCV genotype 1, 2, 4, 5, or 6 infection and compensated cirrhosis. These findings could help simplify treatment algorithms and reduce treatment burden.

FUNDING

AbbVie.

Safety results from a pooled analysis of randomized, controlled phase II and III clinical trials and interim data from an open-label extension trial of the interleukin-12/23 monoclonal antibody, briakinumab, in moderate to severe psoriasis

BACKGROUND

Anti-interleukin-12/23 treatment (anti-IL-12/23) has recently demonstrated significant efficacy for moderate to severe psoriasis, yet potential safety signals warrant further investigation.

OBJECTIVES

Expand safety findings for the anti-IL-12/23, briakinumab, beyond individual phase II and III clinical trials.

METHODS

Safety data pooled from five phase II and III clinical trials (parent studies) and an open-label extension study (OLE), through 22 October 2010; patients with ≥ 1 dose of briakinumab in a parent study or the OLE are included. All parent study briakinumab treatment groups were combined with the OLE population, which received 100-mg briakinumab every 4 weeks. Adverse events (AEs) were collected from the first dose of briakinumab, whether in a parent study or the OLE, through 45 days post-last dose.

RESULTS

Two thousand five hundred and twenty patients (4704 patient-years drug exposure) received ≥ 1 dose of briakinumab during the interim period: 5.6% withdrew due to AEs. Serious infections occurred in 1.3% and malignancies in 2.6% (including 1.0% basal cell carcinoma, 0.8% squamous cell carcinoma). Twenty-seven major adverse cardiovascular events (MACE) occurred, seven in one parent study and 20 in the OLE (incidence = 0.57 events/100 PY). Four cardiovascular risk factors were retrospectively found to be significant predictors for MACE during briakinumab exposure: history of cardiovascular disease, diabetes, body mass index (≥ 30) and baseline blood pressure (systolic ≥ 140 or diastolic ≥ 90).

CONCLUSIONS

Pooled briakinumab safety results from five parent studies and an OLE suggest increased rates of infections, malignancies and MACE, and that patients receiving anti-IL-12/23 treatment for moderate to severe psoriasis should be monitored for these potential safety signals.

The laparoscopic modified Sugarbaker technique is safe and has a low recurrence rate: a multicenter cohort study

BACKGROUND

Parastomal hernia is a frequent complication of intestinal stomata. Mesh repair gives the best results, with the mesh inserted via laparotomy or laparoscopically. It was the aim of this retrospective multicenter study to determine the early and late results of the laparoscopically performed, modified Sugarbaker technique with ePTFE mesh.

METHODS

From 2005 to 2010, a total of 61 consecutive patients (mean age = 61 years), with a symptomatic parastomal hernia, underwent laparoscopic repair using the modified Sugarbaker technique with ePTFE mesh. Fifty-five patients had a colostomy, 4 patients an ileostomy, and 2 a urostomy according to Bricker. The records of the patients were reviewed with respect to patient characteristics, postoperative morbidity, and mortality. All patients underwent physical examination after a follow-up of at least 1 year to detect a recurrent hernia. Morbidity rate was 19 % and included wound infection (n = 1), ileus (n = 2), trocar site bleeding (n = 2), reintervention (n = 2), and pneumonia (n = 1). One patient died in the postoperative period due to metastasis of lung carcinoma that caused bowel obstruction. Concomitant incisional hernias were detected in 25 of 61 patients (41 %) and could be repaired at the same time in all cases. A recurrent hernia was found in three patients at physical examination, and in one patient an asymptomatic recurrence was found on a CT scan. The overall recurrence rate was 6.6 % after a mean follow-up of 26 months.

CONCLUSION

The laparoscopic Sugarbaker technique is a safe procedure for repairing parastomal hernias. In our study, the overall morbidity was 19 % and the recurrence rate was 6.6 % after a mean follow-up of 26 months. Moreover, the laparoscopic approach revealed concomitant hernias in 41 % of the patients, which could be repaired successfully at the same time.

A phase 2, 24-week, randomized, placebo-controlled, double-blind study examining the efficacy and safety of an anti-interleukin-12 and -23 monoclonal antibody in patients with relapsing-remitting or secondary progressive multiple sclerosis

BACKGROUND

Interleukins 12 and 23 (IL-12/23) have been implicated in multiple sclerosis (MS) pathogenesis. This study assessed the efficacy and safety of ABT-874, a monoclonal anti-IL-12/23 antibody, in active relapsing-remitting MS (RRMS) or secondary progressive MS (SPMS).

METHODS

In this 24-week study, patients with RRMS or SPMS received ABT-874 200 mg every other week (EOW), ABT-874 200 mg every week (EW), or placebo. The cumulative number of gadolinium-enhanced lesions, relapse rate, disability progression, and adverse events were measured.

RESULTS

215 patients were randomized (ABT-874 200 mg EOW, N = 76; ABT-874 200 mg EW, N = 70; placebo, N = 69). At week 24, gadolinium-enhanced lesions were statistically significantly reduced with ABT-874 200 mg EOW vs. placebo (mean number [SD]: 5.4 [8.1] vs. 7.6 [14.4], p = 0.003), but not with ABT-874 200 mg EW (6.8 [11.3], p = 0.134). Mean relapse rate (relapses/y) was significantly lower for ABT-874 200 mg EW vs. placebo (0.1 [95% CI -0.0, 0.3] vs. 0.5 [0.2, 0.8], p = 0.007). Changes from baseline in disability scores and incidences of adverse events were not significantly different across treatment groups, although a numerically greater percentage of serious adverse events was reported for ABT-874 treatment groups.

CONCLUSIONS

Although rates of adverse events were not significantly different between ABT-874 treatment groups and placebo, the magnitude of ABT-874 efficacy was less than that observed with other agents currently in development for MS treatment. Anti-IL-12/23 monotherapy does not appear to warrant further testing as monotherapy treatment for MS.

Human lactoferrin stimulates skin keratinocyte function and wound re-epithelialization

BACKGROUND

Human lactoferrin (hLF), a member of the transferrin family, is known for its antimicrobial and anti-inflammatory effects. Recent studies on various nonskin cell lines indicate that hLF may have a stimulatory effect on cell proliferation.

OBJECTIVES

To study the potential role of hLF in wound re-epithelialization.

MATERIALS AND METHODS

The effects of hLF on cell growth, migration, attachment and survival were assessed, with a rice-derived recombinant hLF (holo-rhLF), using proliferation analysis, scratch migration assay, calcein-AM/propidium iodide staining and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) method, respectively. The mechanisms of hLF on cell proliferation and migration were explored using specific pathway inhibitors. The involvement of lactoferrin receptor low-density lipoprotein receptor-related protein 1 (LRP1) was examined with RNA interference technique. An in vivo swine second-degree burn wound model was also used to assess wound re-epithelialization.

RESULTS

Studies revealed that holo-rhLF significantly stimulated keratinocyte proliferation which could be blocked by mitogen-activated protein kinase (MAPK) kinase 1 inhibitor. Holo-rhLF also showed strong promoting effects on keratinocyte migration, which could be blocked by either inhibition of the MAPK, Src and Rho/ROCK pathways, or downregulation of the LRP1 receptor. With cells under starving or 12-O-tetradecanoylphorbol-13-acetate exposure, the addition of holo-rhLF was found greatly to increase cell viability and inhibit cell apoptosis. Additionally, holo-rhLF significantly increased the rate of wound re-epithelialization in swine second-degree burn wounds.

CONCLUSIONS

Our studies demonstrate the direct effects of holo-rhLF on wound re-epithelialization including the enhancement of keratinocyte proliferation and migration as well as the protection of cells from apoptosis. The data strongly indicate its potential therapeutic applications in wound healing.

Computational intelligence in earth sciences and environmental applications: issues and challenges

This paper introduces a generic theoretical framework for predictive learning, and relates it to data-driven and learning applications in earth and environmental sciences. The issues of data quality, selection of the error function, incorporation of the predictive learning methods into the existing modeling frameworks, expert knowledge, model uncertainty, and other application-domain specific problems are discussed. A brief overview of the papers in the Special Issue is provided, followed by discussion of open issues and directions for future research.

Once daily clarithromycin extended-release vs twice-daily amoxicillin/clavulanate in patients with acute bacterial sinusitis: a randomized, investigator-blinded study

OBJECTIVE

To compare the efficacy and tolerability of clarithromycin extended-release (ER) to amoxicillin/ clavulanate in patients diagnosed with acute bacterial sinusitis.

RESEARCH DESIGN AND METHODS

In a controlled, multicenter, investigator-blinded study, 437 ambulatory patients at least 12 years old with signs/symptoms and radiographic findings of acute sinusitis were randomized to receive clarithromycin ER 1000 mg once daily or amoxicillin/ clavulanate 875 mg/l25 mg twice daily for 14 days.

MAIN OUTCOME MEASURES

Clinical and bacteriological response rates were determined at a test-of-cure visit, which was conducted up to 10 days following the completion of treatment. Radiological response was assessed at a follow-up visit.

RESULTS

The clinical cure rate in clinically evaluable patients was 98% (184/188) in the clarithromycin ER group and 97% (179/185) in the amoxicillin/clavulanate group (95% CI for the difference in rates [-2.4%, 4.7%]). Clinical cure was sustained at the follow-up visit (96% for each treatment group). The pathogen eradication rates were 94% (61/65) in the clarithromycin ER group and 98% (61/62) in the amoxicillin/clavulanate group (95% CI for difference in rates [-12.0%, 2.9%]). The radiological success rate was 94% (172/183) in both the clarithromycin ER and amoxicillin/clavulanate groups (95% CI for difference in rates [-4.9%, 4.9%]). Symptomatic improvement or relief was observed as early as 2 days-5 days after the initiation of study drug, with a statistically significantly higher resolution rate of sinus pressure (p = 0.027) and improvement/resolution rate of nasal congestion (p = 0.035) during treatment with clarithromycin ER. The resolution/improvement rate at the test-of-cure visit for each treatment group was > or = 94% for the primary acute sinusitis signs/symptoms, with a statistically significantly higher resolution/improvement rate of purulent nasal discharge with clarithromycin ER (p = 0.010). Both study drugs had a positive and rapid impact on quality of life. Patients reported a high level of satisfaction and probability of using either study antibiotic again, and health care resource use was low, with slightly fewer sinusitis-related physician and outpatient visits required by patients in the clarithromycin ER group (p = 0.055). The treatment groups were comparable with respect to incidence of drug-related adverse events.

CONCLUSION

In this multinational population of patients with acute bacterial sinusitis, clarithromycin ER was comparable, and for selected measures superior, to amoxicillin/clavulanate based on clinical, bacteriological, and radiological responses as well as quality of life measures, satisfaction with antibiotic therapy, and health care resource utilization.

Possible association of a cholecystokinin promotor polymorphism (CCK-36CT) with panic disorder

We searched for mutations in the CCK gene in panic disorder with single-strand conformational polymorphism (SSCP) analysis of the three exons and promotor region of the gene. We found a C-->T transition at position -36 (CCK(-36C-->T)) in a GC box, a binding site for transcription factor Sp1, in the promotor region. The allele frequency was 0.168 (95% CI, 0.116-0.221) in 98 persons with panic disorder and 0.083 (95% CI, 0.059-0.107) in 247 geographically matched, unscreened controls. A transmission disequilibrium test based on panic disorder as the affected phenotype was nonsignificant (chi2 = 0.93), but when panic disorder or attacks were considered as affected, statistically significant transmission disequilibrium was detected (chi2 = 4.00, P < 0.05). Linkage analysis was uninformative. In exploratory analyses to search for clinical correlations, the "T" allele was found in 59% of 22 persons with panic attacks but not panic disorder, compared with 31% of those who met the criteria for panic disorder. An association between the CCK polymorphism and panic disorder cannot be considered established due to the inconsistencies in the results noted above, but if the provisional association can be replicated, the findings are consistent with CCK(-36C-->T) being a disease-susceptibility allele that alone is neither necessary nor sufficient to cause panic disorder but that increases vulnerability by acting epistatically.

The duration of viral suppression during protease inhibitor therapy for HIV-1 infection is predicted by plasma HIV-1 RNA at the nadir

OBJECTIVE

To determine markers that are associated with the durability of virologic response to therapy with HIV protease inhibitors in HIV-infected individuals.

DESIGN

This study encompassed two retrospective analyses of the duration of virologic response to protease inhibitor therapy. The first analysis included 29 patients receiving either monotherapy or combination therapy with the protease inhibitor ritonavir whose plasma HIV RNA levels rebounded from the point of greatest decline with mutations associated with resistance to ritonavir. The second analysis included a cohort of 102 patients who initially responded to randomized treatment with either monotherapy with ritonavir or combination therapy with ritonavir and zidovudine.

METHODS

Durability of response was defined as the time from the initiation of therapy to the point at which plasma HIV RNA displayed a sustained increase of at least 0.6 log10 copies/ml from the nadir value. In the first analysis, durability of response was analyzed with respect to baseline HIV RNA, HIV RNA at the nadir, and the drop in HIV RNA from baseline to the nadir. In the second analysis, time to rebound was examined using Kaplan-Meier analysis, stratifying by either baseline HIV RNA or HIV RNA at the nadir.

RESULTS

In both analyses, the durability of response was not highly associated with either baseline RNA or the magnitude of RNA decline from baseline. Instead, a strong relationship was observed between the durability of response and the nadir plasma HIV-1 RNA value (P < 0.01). The nadir in viral load was generally reached after 12 weeks of randomized therapy.

CONCLUSIONS

Viral RNA determinations at intermediate timepoints may be prognostic of impending virologic failure of protease inhibitor therapy. Therapeutic strategies that allow intensification of initial antiretroviral regimens in the subset of patients with incomplete virological response before the emergence of high level resistance should be investigated.

Multiple-dose pharmacokinetics of ritonavir in human immunodeficiency virus-infected subjects

The multiple-dose pharmacokinetics of ritonavir were investigated in four groups of human immunodeficiency virus-positive male subjects (with 16 subjects per group) under nonfasting conditions; a 3:1 ritonavir:placebo ratio was used. Ritonavir was given at 200 (group I), 300 (group II), 400 (group III), or 500 (group IV) mg every 12 h for 2 weeks. The multiple-dose pharmacokinetics of ritonavir were moderately dose dependent, with the clearance for group IV (6.8 +/- 2.7 liters/h) being an average of 32% lower than that for group I (10.0 +/- 3.2 liters/h). First-pass metabolism should be minimal for ritonavir. The functional half-life, estimated from peak and trough concentrations, were similar among the dosage groups, averaging 3.1 and 5.7 h after the morning and evening doses, respectively. The area under the concentration-time curve at 24 h (AUC24) and apparent terminal-phase elimination rate constant remained relatively time invariant, but predose concentrations decreased 30 to 70% over time. Concentration-dependent autoinduction is the most likely mechanism for the time-dependent pharmacokinetics. The Km and initial maximum rate of metabolism (Vmax) values estimated from population pharmacokinetic modeling (nonlinear mixed-effects models) were 3.43 microg/ml and 46.9 mg/h, respectively. The group IV Vmax increased to 68 mg/h after 2 weeks. The maximum concentration of ritonavir in serum (Cmax) and AUC after the evening doses were an average of 30 to 40% lower than the values after the morning doses, while the concentration at 12 h was an average of 32% lower than the predose concentration, probably due to protracted absorption. Less than 2% of the dose was eliminated unchanged in the urine. Triglyceride levels increased from the levels at the baseline, and the levels were correlated with baseline triglyceride levels and AUC, Cmax, or predose concentrations.

Cavernous hemangiomas of the dura mater at the convexity. Report of a case and therapeutical considerations

A rare case of cavernous angioma of the dura mater at the convexity is presented. In comparison with the more common cavernous hemangiomas that arise from dural sinuses, the ones on the convexity have a much better prognosis. They do not seem to be associated with spontaneous hemorrhage, their removal is simpler and, transoperatory bleeding, if it occurs, is scanty. Computerized tomography detects the presence of cavernous angiomas of the convexity in only 70% of the cases, magnetic resonance imaging in 100%.

A cosmid contig and high resolution restriction map of the 2 megabase region containing the Huntington's disease gene

The quest for the mutation responsible for Huntington's disease (HD) has required an exceptionally detailed analysis of a large part of 4p16.3 by molecular genetic techniques, making this stretch of 2.2 megabases one of the best characterized regions of the human genome. Here we describe the construction of a cosmid and P1 clone contig spanning the region containing the HD gene, and the establishment of a detailed, high resolution restriction map. This ordered clone library has allowed the identification of several genes from the region, and has played a vital role in the recent identification of the Huntington's disease gene. The restriction map provides the framework for the detailed analysis of a region extremely rich in coding sequences. This study also exemplifies many of the strategies to be used in the analysis of larger regions of the human genome.

Changes in the xanthine dehydrogenase/xanthine oxidase ratio in the rat kidney subjected to ischemia-reperfusion stress: preventive effect of some flavonoids

The enzyme xanthine oxidase has been implicated in the tissue oxidative injury after ischemia-reperfusion. This enzyme, which is a source of oxygen free radicals, is formed from a dehydrogenase form during ischemia. The ratio dehydrogenase/oxidase of rat kidney homogenates decreases during the ischemia and the reperfusion. Two flavonoids, quercetin and silybin, characterized as free radical scavengers, exert a protective effect preventing the decrease in the dehydrogenase/oxidase ratio observed during ischemia-reperfusion. The mechanism of this effect and the role of flavonoids in the ischemia-reperfusion tissue damage is discussed.

Characterization of a yeast artificial chromosome contig spanning the Huntington's disease gene candidate region

The Huntington's disease (HD) gene has been localized by recombination events to a region covering 2.2 megabases (Mb) DNA within chromosome 4p16.3. We have screened three yeast artificial chromosome (YAC) libraries in order to isolate and characterize 44 YAC clones mapping to this region. Approximately 50% of the YACs were chimaeric. Unstable YACs were identified across the whole region, but were particularly prevalent around the D4S183 and D4S43 loci. The YACs have been assembled into a contig extending from D4S126 to D4S98 covering roughly 2 Mb DNA, except for a gap of about 250 kilobases (kb). The establishment of a YAC contig which spans the region most likely to contain the HD mutation is an essential step in the isolation of the HD gene.

Coronary vascular resistance during halothane anesthesia

To study the effect of halothane on the coronary circulation, the circumflex diastolic coronary vascular resistance was measured in the working heart and total mean coronary resistance (TCR) in the isolated nonworking heart of the dog during administration of 100 per cent oxygen and during administration of 2--3 per cent halothane in oxygen. In the working heart, when the diastolic aortic pressure was kept at a nearly control level, halothane induced decreases of 12 per cent in circumflex diastolic coronary vascular resistance and 18 per cent in left ventricular arteriovenous oxygen content difference and no significant change in diastolic coronary blood flow. This effect occurred in spite of the absence of any significant change of myocardial oxygen consumption. In the nonworking beating, arrested or fibrillating heart, halothane induced a decrease of 24 per cent in total mean coronary resistance. Since the decrease in circumflex diastolic coronary vascular resistance in the working heart connot be attributed to myocardial hypoxia and since the results in the isolated nonworking heart eliminate the influences of mechanical and neurohumoral factors on coronary resistance, it is concluded that the observed decrease in resistance is probably due to vasodilation produced by a direct action of halothane on the coronary vessels. This effect was not modified by beta-adrenergic blockade.