Safety and efficacy of vesatolimod (GS-9620) in patients with chronic hepatitis B who are not currently on antiviral treatment.

Vesatolimod is an oral agonist of toll-like receptor 7 designed to minimize systemic exposure and side effects. We assessed the safety and efficacy of vesatolimod in viremic chronic hepatitis B (CHB) patients not currently on oral antiviral treatment (OAV) in a phase 2, multicentre, double-blind, randomized, placebo-controlled study. A total of 192 patients stratified by HBeAg status and alanine aminotransferase level were randomized 2:2:2:1 to receive oral vesatolimod (1-, 2- or 4-mg) or placebo once weekly for 12 weeks; tenofovir disoproxil fumarate (300-mg daily) was administered daily for 48 weeks. Efficacy was assessed by quantitative serum HBsAg decline at Week 24 from baseline. In addition to safety assessments, changes in whole-blood interferon-stimulated gene (ISG) transcripts and serum cytokines were explored. Most patients were male (64.1%) and HBeAg-negative (60.9%) at baseline. Among vesatolimod-treated patients, most (60.4%-69.1%) experienced ≥1 treatment-emergent adverse event; the majority were mild or moderate in severity. No clinically meaningful differences in HBsAg changes from baseline were observed between treatment groups. No patients experienced HBsAg loss, while 3 patients experienced HBeAg loss and hepatitis B e-antibody seroconversion at week 48. HBV DNA suppression rates were similar across all treatment arms at Week 24. ISG15 induction was dose-dependent and did not correlate with HBsAg changes. A small proportion of patients exhibited dose-dependent interferon-α induction that correlated with grade of influenza-like adverse events. Overall, vesatolimod is safe and well tolerated in CHB patients. Although consistent dose-dependent pharmacodynamic induction of ISGs was demonstrated, it did not result in clinically significant HBsAg decline.

Applying Mass Cytometry to the Analysis of Lymphoid Populations in Transplantation.

Single-cell flow cytometric techniques have been indispensable to improving our understanding of the phenotype and function of immune cell subsets that are important in both rejection and tolerance after transplant. Mass cytometry, or cytometry by time of flight, is a single-cell-based platform that utilizes antibodies conjugated to rare heavy metal ions for analysis of cellular proteins by a time-of-flight mass spectrometer. This new technology allows for the evaluation of >40 simultaneous cellular parameters in a single sample because the limitation of spectral overlap, seen in conventional flow cytometry, is eliminated. In this review, we discuss the current state of mass cytometry, describe the advantages and disadvantages compared with multiparameter flow cytometry, introduce novel methods of high-dimensional data analysis and visualization, and review some recent studies using mass cytometry to profile the immune systems of healthy people and transplant recipients.

Efficacy of chewed vs. crushed lanthanum on phosphorus binding in healthy volunteers.

BACKGROUND AND AIM: For effective dietary phosphorous (P) binding, patients are recommended to chew lanthanum tablets completely before swallowing, with or immediately after meals. However, some patients are unable to chew the tablets. It is not known if crushing the tablets prior to taking them with food is as efficacious as chewing them. This study was conducted to compare the efficacy of chewed vs. crushed lanthanum on P binding. METHODS: 12 healthy subjects were randomized and crossed-over to receive: (A) a standardized meal containing 1 g (32 mmol) of elemental P; (B) a single 1 g oral dose of lanthanum, chewed and taken with the standardized meal; (C) a single 1 g oral dose of lanthanum, crushed into a fine powder using a pestle and mortar, mixed with applesauce, and taken with the standardized meal. Blood and urine samples were collected from baseline to 8 hours after meal completion. The changes in serum P, urinary P excretion and fractional excretion of P (FePi) were compared among treatment arms using ANOVA. RESULTS: Co-administration of lanthanum with meal resulted in a smaller increase in serum P, compared with meal alone (p < 0.05). The smaller increase in serum P was similar for both chewed and crushed lanthanum. The amount of P excreted and FePi were also lower when chewed or crushed lanthanum was administered with meal, compared with meal alone (p = n.s. and p < 0.05, respectively). CONCLUSION: Both chewed and crushed lanthanum are effective in lowering P absorption after a dietary P load.

In situ phylogenetic structure and diversity of wild Bradyrhizobium communities.

Bacteria often infect their hosts from environmental sources, but little is known about how environmental and host-infecting populations are related. Here, phylogenetic clustering and diversity were investigated in a natural community of rhizobial bacteria from the genus Bradyrhizobium. These bacteria live in the soil and also form beneficial root nodule symbioses with legumes, including those in the genus Lotus. Two hundred eighty pure cultures of Bradyrhizobium bacteria were isolated and genotyped from wild hosts, including Lotus angustissimus, Lotus heermannii, Lotus micranthus, and Lotus strigosus. Bacteria were cultured directly from symbiotic nodules and from two microenvironments on the soil-root interface: root tips and mature (old) root surfaces. Bayesian phylogenies of Bradyrhizobium isolates were reconstructed using the internal transcribed spacer (ITS), and the structure of phylogenetic relatedness among bacteria was examined by host species and microenvironment. Inoculation assays were performed to confirm the nodulation status of a subset of isolates. Most recovered rhizobial genotypes were unique and found only in root surface communities, where little bacterial population genetic structure was detected among hosts. Conversely, most nodule isolates could be classified into several related, hyper-abundant genotypes that were phylogenetically clustered within host species. This pattern suggests that host infection provides ample rewards to symbiotic bacteria but that host specificity can strongly structure only a small subset of the rhizobial community.

Evaluation of a potential drug interaction between sucralfate and aspirin.

Recent studies have demonstrated a cytoprotective effect of sucralfate on gastric mucosa in patients receiving aspirin. The potential drug interaction between sucralfate and aspirin was evaluated in a randomized crossover manner in 12 healthy men. Subjects were initially given a single dose of aspirin alone or in combination with sucralfate for 2 days. The drug dosing schedule was then reversed after 1 week. Sixteen blood samples were drawn after each aspirin dose for HPLC assay of aspirin and its metabolites. Pharmacokinetic parameters were calculated for aspirin, salicylic acid, and salicyluric acid. None of these parameters demonstrated any statistically significant differences between the two treatment groups. The combined use of sucralfate and aspirin is therefore not likely to result in a clinically significant pharmacokinetic drug interaction. The systemic therapeutic effect of aspirin is not expected to be altered when sucralfate is used concurrently in patients receiving chronic aspirin therapy.

Clinical pharmacokinetics of metronidazole and other nitroimidazole anti-infectives.

Metronidazole was first introduced for the treatment of trichomoniasis. Its therapeutic use has subsequently been expanded to include amoebiasis, giardiasis and, more recently, anaerobic infections. Most of the early pharmacokinetic studies employed nonspecific assays such as microbiological and chemical assays. These assays were not able to differentiate the parent drug from the metabolites or other interfering substances. Pharmacokinetic data obtained through the use of specific chromatographic techniques provide the basis for this review of recent pharmacokinetic findings concerning metronidazole and other nitroimidazole antibiotics. When given intravenously or orally at usual recommended doses, metronidazole attains concentrations well above the minimum inhibitory concentrations for most susceptible micro-organisms. The drug has an oral bioavailability approaching 100%. Rectal and vaginal administration results in a smaller amount of drug absorption and lower serum concentrations. Metronidazole has limited plasma protein binding but can attain very favourable tissue distribution, including into the central nervous system. The drug is extensively metabolised by the liver to form 2 primary oxidative metabolites: the hydroxy and acetic acid metabolites. The kidney is responsible for the elimination of only a small amount of the parent drug; however, normal excretion of the 2 metabolites is dependent on the integrity of kidney function. The metabolism of metronidazole was found to vary among patient groups. Preterm and term infants have lower total body clearance (CL) and prolonged elimination half-lives. However, children older than 4 years old were observed to have pharmacokinetic parameters similar to those in adults. Reduced CL was also observed in children who are malnourished. Elderly patients have reduced renal excretion of both the parent drug and hydroxy metabolite. Pharmacokinetic parameters in pregnant patients were not significantly different from those in nonpregnant women; however, the drug is distributed into breastmilk and the infant will be exposed to the drug through the nursing mother. Patients undergoing gastrointestinal surgery or having enteric diseases and those who are hospitalised or critically ill also have altered pharmacokinetics. Metabolism of the drug is reduced in patients with liver dysfunction, giving delayed production of metabolites. In contrast, renal failure has little effect on the elimination of the parent drug, but affects the excretion of the metabolites more significantly. Haemodialysis was found to remove a substantial amount of the metronidazole while the effect of peritoneal dialysis was more limited. Energy and protein deficient diets as well as occupational exposure to gasoline did not alter metronidazole pharmacokinetics. However, the effect of alcohol consumption on metronidazole CL requires further study.(ABSTRACT TRUNCATED AT 400 WORDS)

Acute and chronic actions of ethanol on CA1 hippocampal responses to serotonin.

The effects of acute or chronic ethanol on serotonin (5-HT)-induced membrane hyperpolarization and inhibition of the slow Ca2(+)-dependent after hyperpolarization (sAHP) were recorded in rat CA1 pyramidal neurons in hippocampal slices using sharp intracellular electrodes. 5-HT (1-100 microM) caused concentration-dependent hyperpolarization of the membrane that was not altered by simultaneous 30 mM ethanol treatment, but blunted by 10 microM buspirone, a weak 5-HT1A agonist. 5-HT (1-30 microM) also partially inhibited (approximately 40%) the sAHP following a burst of five or more action potentials. Initially ethanol (30 mM) alone did not alter the sAHP, but over a period of 38 min, a slow increase in amplitude (approximately 40%) was observed. 5-HT-mediated inhibition of the sAHP was significantly greater with ethanol present, regardless of the length of exposure. Pyramidal neurons in hippocampal slices prepared from ethanol-dependent animals showed no obvious signs of withdrawal related hyperexcitability and neither concentration-dependent membrane hyperpolarization nor sAHP inhibition caused by 5-HT were significantly changed from responses in controls. These results suggest that hyperpolarizing responses to 5-HT in hippocampal CA1 pyramidal neurons are functionally resistant to acute or chronic ethanol treatment. 5-HT-mediated inhibition of the sAHP is enhanced by ethanol acutely, but does not show an adaptive change as a result of ethanol dependence.

Immunologically induced histamine release from rat peritoneal mast cells is enhanced by low levels of substance P.

Although direct activation of mast cells by high concentrations (>10(-6) M) of substance P is well established, the effect of sub-micromolar concentrations of the neuropeptide on mast cell activation has not been reported. We hence investigated if substance P would modulate immunologic activation of mast cells by studying the effect of the neuropeptide on anti-rat immunologlobulin E antibody (anti-IgE)-induced histamine release from purified rat peritoneal mast cells. We observed that substance P could dose-dependently potentiate anti-IgE-induced histamine release from rat peritoneal mast cells at concentrations (3x10(-9) M to 3x10(-7) M) which alone induced insignificant or low level of histamine release. While the potentiating effect of substance P was not suppressed by any of the non-peptide tachykinin receptor antagonists CP99994 ((2S,3S)-3-(2-methoxybenzylamino)-2-phenylpiperidine), SR48968 ((S)-N-methyl-N-(4-acetylamino-4-phenylpiperidino)-2-(3,4-dichlorophenyl) butyl-benzamide) and SR142801 ((S)-(N)-(1-[3-(1-benzoyl-3(3,4-dichlorophenyl)piperidine-3-yl)propyl]-4-phenylpiperidin-4-yl)-N-methyl-acetamide), it was mimicked by compound 48/80 and suppressed by benzalkonium chloride. Hence, substance P enhanced anti-IgE-induced histamine release through a similar receptor-independent mechanism as the direct mast cell activating action of polybasic compounds. Since high concentrations of substance P required for directly activating mast cells may not be achievable physiologically, the enhancing actions of the neuropeptide on the immunologic activation of mast cells may be more clinically relevant in the pathogenesis of various inflammatory conditions.

The effects of nandrolone decanoate on nutritional parameters in hemodialysis patients.

AIMS: Malnutrition with hypoalbuminemia is an independent predictor of mortality in end-stage renal disease patients. Anabolic steroids reduce protein catabolism and therefore may improve nutritional parameters. This study was undertaken to determine the effects of the anabolic steroid nandrolone decanoate on the nutritional status of hemodialysis patients. Secondary endpoints were to examine the effects of androgen therapy on hematocrit and erythropoietin (EPO) dose. PATIENTS AND METHODS: Medical records of chronic hemodialysis patients who received nandrolone decanoate for greater than 30 days were reviewed. Data collected included: demographics, dose, frequency, duration of treatment and cumulative dose of nandrolone. Baseline albumin, transferrin, dry weight, phosphorus, creatinine, hematocrit and erythropoietin dose were obtained for comparison with values after treatment. RESULTS: Of the 9 patients evaluated (mean +/- SD: age 55+/-28 years, 4/9 male), 2 patients received nandrolone doses of 25 mg intramuscularly (i.m.) every week, while the remaining 7 patients received 100 mg i.m. every 2 weeks. The mean +/- SD duration of treatment was 96+/-43 days, with a mean +/- SD cumulative dose of 656+/-371 mg. The mean +/- SD baseline albumin was 2.9+/-0.6 mg/dl which increased to 3.3+/-0.4 mg/dl after treatment (p = 0.045). Dry weight increased from a mean +/- SD of 64.4+/-11.7 kg to 66.0+/-10.9 kg after nandrolone therapy (p = 0.028). Mean +/- SD hematocrit at baseline was 28.2+/-4.5% and increased to 33.2+/-5.1% (p = 0.033). The dose of EPO was reduced in 4 patients (44%) during nandrolone therapy. CONCLUSIONS: Nandrolone significantly improved markers of nutritional status in our hemodialysis patients. This therapy may also enhance the hematopoietic effects of EPO.

Gender effect on diuretic response to hydrochlorothiazide and furosemide.

Gender has been shown to elicit differences in drug disposition and response to therapeutic agents. We measured the diuretic response to oral hydrochlorothiazide, oral and intravenous furosemide in 6 male and 6 female normal volunteers. After fasting overnight, each subject received single doses of the individual diuretics or no treatment on 4 separate days. Total urine output was collected over the next 24 hours for volume measurement and determination of sodium and potassium concentrations. There was no statistically significant difference found between male and female subjects with respect to urine flow rate, sodium, and potassium excretion rates among the treatments. However, when natriuretic response was adjusted for mg/kg of the intravenous furosemide dose received, male subjects had a higher peak sodium excretion rate than the female subjects. Results of this study reveal a gender-related difference on the natriuretic response to diuretics. Further studies are necessary to identify if this gender-related difference is caused by differences in drug metabolism, disposition, or intrinsic diuretic responsiveness at the site of action.

Vascular access thrombosis during recombinant human erythropoietin therapy.

The increased incidence of vascular access thrombosis (VAT) associated with recombinant human erythropoietin (r-HuEPO) therapy is multifactorial and controversial. Sixty-three hemodialysis patients who received > or = 12 weeks of r-HuEPO therapy were prospectively followed for the incidence of VAT. Those who experienced VAT (Group 1) were compared with those who did not (Group 2). The patients initially received r-HuEPO 50 U/kg intravenously three times a week. The dose was adjusted for a target hematocrit (t-Hct) of 30-33%. Twenty-five of the 63 patients (40%) experienced VAT (Group 1). These patients were older (mean, 54.0 +/- 14.0 years versus 47.3 +/- 15.0 years, p = 0.08). There was no difference between Groups 1 and 2 with respect to the baseline Hct level (21.5 +/- 2.9% versus 21.4 +/- 4.3%), the number of patients who achieved t-Hct (20 versus 28), and the mean time to reach t-Hct (18.6 +/- 15.1 weeks versus 16.9 +/- 16.2 weeks). However, 20 of 25 Group 1 patients (80%) were diabetic compared with only 18 of 38 Group 2 patients (47%, p = 0.0169, by Fisher's exact test). In addition, the types of vascular access differed markedly between the two groups: arteriovenous (AV) grafts/AV fistulae/Permcaths, Group 1: 21/3/1 versus Group 2: 15/21/2, p = 0.0018. It was concluded that the occurrence of VAT in r-HuEPO treated patients was not related to the patient's hematologic response to the drug, but rather, it depended upon the integrity of the patient's vasculature and the type of vascular access used.

Mycotic (Aspergillus) arteritis resulting in fatal subarachnoid hemorrhage: a case report.

A seventy-one year-old Japanese man suffering from carcinoma of the common bile duct died from subarachnoid hemorrhage secondary in intracranial mycotic arteritis (MA). Repeated cultures of the discharge from the draining tubes, the tip of intravenous hyperalimentation catheters, blood, sputum, and urine failed to grow any fungus. Autopsy disclosed MA due to Aspergillus at the terminal portion of the right internal carotid artery close to the posterior communicating artery.

Transient encephalopathy related to rapidly and markedly elevated blood pressure in acute stage of hypertensive cerebral hemorrhage--relationship to hypertensive encephalopathy--a case report.

A seventy-two-year-old man with hypertensive cerebral hemorrhage acutely developed severe headache, nausea, vomiting, agitation, and disorientation with abrupt rise in blood pressure on the sixth day after the onset. At that time, there were no remarkable changes in focal neurologic deficits, and repeated brain CT scans revealed a small hematoma located in the right basal ganglia without further enlargement or herniation. Blood chemistry and arterial gas analysis were within the normal ranges except for a slight rise in blood urea nitrogen. Similar episodes occurred three times within two days, and each time the cerebral symptoms disappeared in accordance with lowering of blood pressure by antihypertensive therapy. Complication of hypertensive encephalopathy was strongly suggested. The authors discuss the pathophysiology of this encephalopathy in relation to cerebral hemorrhage.

Determinants of drug removal by continuous hemofiltration.

Continuous hemofiltration was conducted in vitro to identify parameters that affect drug transport across hemofilter membranes. The removal of seven drugs with different molecular weights and protein binding characteristics was assessed. Sieving coefficients were determined with both blood and saline using polysulfone, polyacrylonitrile and polyamide membranes. Drug sieving coefficients obtained with saline were generally higher than those obtained with blood. Molecular weights of the drugs did not correlate with the magnitude of drug sieving. Sieving coefficients in blood were also predicted from saline data assuming plasma protein binding is responsible for the reduced drug sieving with blood. For drugs that are highly protein bound, protein binding was the primary factor limiting drug sieving. Presence of plasma proteins also had a modest effect on sieving of other drugs. The sieving coefficients obtained with the polyacrylonitrile membrane tend to be different from those obtained with the other hemofilters. Drug-membrane interaction may contribute to the differences in drug transport among the membranes.

Removal of cephalosporins by continuous arteriovenous ultrafiltration (CAVU) and hemofiltration (CAVH).

Cephalosporins are used with increasing frequency for sepsis treatment in patients receiving CAVU and CAVH. The different cephalosporins share the same basic molecular structure, yet they exhibit varied extent of plasma protein binding. Different amounts of the antibiotics may be removed by the ultrafiltration procedure because of these variations of physicochemical properties. We evaluated the sieving of eight new cephalosporins across the hemofilter membrane using an in vitro model. Bovine blood was perfused through polysulfone membranes at blood and ultrafiltrate flow rates of 100 and 20 ml/min respectively. Arterial plasma, venous plasma and ultrafiltrate drug concentrations were used to determine sieving coefficients. The sieving coefficients correlated well with the ultrafiltrate-arterial plasma drug concentration ratio (r = 0.679-0.972) but poorly with the extent of protein binding. Factors other than protein binding may therefore affect the drug sieving. Based on the findings, it was predicted that 0.2-21.9% of the daily cephalosporin dose may be removed by the CAVU and CAVH treatment. The need to alter drug dosages depends on the techniques of the ultrafiltration and hemofiltration procedure, the kinetics of the cephalosporins in patients, the sensitivity of the pathogen and the nature of the infection.

Phosphate-binding capacities of calcium and aluminum formulations.

Calcium and aluminum phosphate binders are used to treat hyperphosphatemia which is responsible for the development of osteodystrophy commonly seen in patients with end-stage renal disease. The purpose of this study was to determine the phosphate binding capacities of several frequently used calcium and aluminum formulations. The effect of formulation types on phosphate binding was evaluated. Calcium and aluminum phosphate binders were administered to six healthy volunteers after phosphate load on separate study days. Total urine outflow was collected afterwards to determine the amount of phosphate recovered, which indicates the ability of the phosphate binder to reduce gastrointestinal phosphate absorption. The amounts of urinary phosphate recovered were different after administration of the phosphate binders. Calcium acetate resulted in the least amount of phosphate excreted. Calcium carbonate suspension, when compared with the tablet formulation, caused a smaller amount of phosphate excreted in the urine. Different phosphate binders formulations were found to have different phosphate binding capacities. Patients should therefore be closely monitored for efficacy after switching from one phosphate binder to another.

Long-term therapy with paricalcitol for secondary hyperparathyroidism in hemodialysis patients.

PURPOSE: The efficacy of the vitamin D analog paricalcitol has mainly been shown in short-term studies. There are limited data regarding long-term treatment with this agent. This purpose of this study was to determine long-term effects of paricalcitol therapy on parathyroid hormone (PTH) suppression and serum levels of calcium, phosphorus and calcium-phosphorus product (Ca x P). PATIENTS AND METHODS: Patients who received paricalcitol for > or = 3 months had the following data collected: demographics, drug dosage, serum PTH, corrected serum calcium concentration, serum phosphorus concentrations and serum Ca x P values. RESULTS: Sixteen patients received paricalcitol for a mean of 18 months. The mean +/- SD dose of paricalcitol was 0.13 +/- 0.12 mcg/kg. The mean +/- SD pre-paricalcitol serum PTH concentration was 705 +/- 423 pg/mL. PTH concentration did not change significantly over the duration of treatment (mean +/- SD: 821 +/- 480 pg/mL). The number of patients who had at least one corrected serum calcium concentration > or = 11.5 mg/dL, one serum phosphorus concentration > or = 6.5 mg/dL, or one Ca x P level > or = 70 were 75%, 94% and 82%, respectively. Hypercalcemia and elevated Ca x P value resulted in a mean of 17% of doses being withheld during therapy. CONCLUSION: During the study, PTH was not adequately suppressed by paricalcitol. This was primarily attributed to withholding paricalcitol doses due to elevated serum calcium and Ca x P levels.

Using activity-based costing to track resource use in group practices.

Research shows that understanding how resources are consumed can help group practices control costs. An American Academy of Orthopaedic Surgeons study used an activity-based costing (ABC) system to measure how resources are consumed in providing medical services. Teams of accounting professors observed 18 diverse orthopedic surgery practices. The researchers identified 17 resource-consuming business processes performed by nonphysician office staff. They measured resource consumption by assigning costs to each process according to how much time is spent on related work activities. When group practices understand how their resources are being consumed, they can reduce costs and optimize revenues by making adjustments in how administrative and clinical staff work.

Apoptosis induced by cisplatin nephrotoxic injury.

An agent often used in cancer treatment, cisplatin may cause acute renal failure after even a single dose. Recent laboratory studies confirmed the induction of renal cell apoptosis by cisplatin. Reduction in cell viability as well as increase in the number of cells with fragmented nuclei correlated with cisplatin exposure in a dose-dependent manner. Gel electrophoresis revealed the presence of a characteristic laddering pattern which was preceded by an increase in caspase-3 activity. As the cisplatin concentration increased beyond 50 microM, the elevation of caspase-3 activity declined, which suggests that necrosis, instead of apoptosis, is more likely to be responsible for cell death secondary to higher cisplatin concentrations. Elucidation of the molecular mechanisms of cisplatin nephrotoxicity may lead to the development of a novel therapeutic strategy that targets cancer cell death while simultaneously minimizing renal injury.

Elimination of vancomycin by continuous arteriovenous hemofiltration.

Continuous arteriovenous hemofiltration (CAVH) is being used increasingly in pediatric patients with acute renal failure and/or other fluid and electrolyte imbalances. At times, vancomycin may be concurrently given for sepsis therapy. We evaluated the removal of vancomycin by CAVH in a 15-month-old male child with renal failure who was receiving the drug for suspected infection of an arterial catheter. Two separate CAVH treatments were performed with polysulfone membranes. Serum samples and ultrafiltrate outflow (n = 6) were collected over 79 h for vancomycin concentration determination. The mean vancomycin concentration in the ultrafiltrate was 90.4 +/- 5.4% of those of the serum. 0.53-1.11 mg of the drug was removed per hour by CAVH at serum concentrations of 12.4-25.4 mg/l. CAVH vancomycin clearance was 0.039-0.050 liter/h. The CAVH drug clearances accounted for 66.2% of the total vancomycin clearance. CAVH is thus a major route of vancomycin elimination. Dosage adjustment and serum concentration monitoring are necessary in patients undergoing CAVH while receiving vancomycin therapy.