Pharmacokinetics of chlortetracycline in maternal plasma and in fetal tissues following oral administration to pregnant ewes

The purpose of this study was to determine if concentrations of chlortetracycline could be detected in fetal plasma or tissues after administering an oral dose of chlortetracycline (CTC; 500 mg/head/day) reported to be effective in controlling Campylobacter spp. abortions. Five pregnant ewes were administered 250 mg/head twice a day (total dose 500 mg/hd/d) for 7 days. On the beginning of day 7, intravenous catheters were surgically implanted or inserted into the fetus and dam. Plasma samples were collected from the ewe and fetus at various time points before and up to 36 hr after the last dose of CTC. All ewes were then sacrificed, and tissues were harvested from the fetus for drug analysis. Concentrations of CTC in maternal plasma were consistent with our previous study and below the minimum inhibitory concentration of Campylobacter abortion isolates. Concentrations of CTC were below the limit of detection in three of five fetal plasma samples and all of the placenta, amniotic fluid, and fetal stomach contents. Low concentrations were detectable in fetal kidney and liver, suggesting that CTC reaches the fetus, although at a variable and low ratio when compared to maternal concentrations.

Pharmacokinetics of tulathromycin in nonpregnant adult ewes

The objectives of this study were to determine plasma concentrations and pharmacokinetic parameters of tulathromycin after a single subcutaneous administration in the cervical region in sheep using the cattle labeled dose of 2.5 mg/kg. Six adult healthy ewes were administered tulathromycin on day 0. Blood samples were collected just prior to dosing and at selected time points for 360 h. Plasma samples were analyzed to determine tulathromycin concentrations, and noncompartmental analysis was performed for pharmacokinetic parameters. The mean maximum plasma concentration was 3598 ng/mL, the mean time to maximum concentration was 1.6 h, and the apparent elimination half-life ranged from 68.1 to 233.1 h (mean 118 h). When comparing our results to goats and cattle, it appears sheep are more similar to cattle in regard to the concentrations observed and pharmacokinetic parameters. In summary, the pharmacokinetics of tulathromycin in sheep appear to be similar enough to those in goats and cattle to recommend similar dosing (2.5 mg/kg SC), assuming that the target pathogens have similar inhibitory concentrations.

Pharmacokinetics of oral chlortetracycline in nonpregnant adult ewes

The objectives of this study were to determine plasma concentrations and pharmacokinetic parameters of feed-grade chlortetracycline (CTC) in sheep after oral administration of 80 or 500 mg/head daily, divided into two equal doses given at 12-h intervals for 8 days. These are the approved, and commonly used but unapproved, feed additive doses, respectively, in the United States for the prevention of ovine infectious abortion. Blood samples were collected just prior to dosing at 0, 12, 24, 72, 96, and 192 h, as well as 4, 8, 12, 24, and 36 h after the last dose, and noncompartmental pharmacokinetic analysis was performed to estimate elimination half-life and area under the plasma concentration-time curve (AUC). Mean observed maximum CTC concentrations (Cmax ) were 20.0 ng/mL (80 mg dose) and 101 ng/mL (500 mg dose). Mean apparent elimination half-life was 18 h (80 mg dose) and 20 h (500 mg dose). Although published data do not exist to estimate plasma CTC concentrations necessary for the prevention of ovine infectious abortion, concentrations reached in our study suggest that either the FDA-approved and FDA-unapproved dosages are not high enough or that the pharmacodynamic parameter relating preventive dose to pathogen minimum inhibitory concentrations is yet to be determined.

Hepatocellular carcinoma patients are advantaged in the current liver transplant allocation system

Patients with hepatocellular carcinoma (HCC) within Milan criteria receive priority on the liver transplant waiting list (WL) and compete with non-HCC patients. Dropout from the WL is an indirect measure of transplant access. Competing risks (CR) evaluation of dropout for HCC and non-HCC patients has not previously been reported. Patients listed between 16 March 2005 and 30 June 2008 were included. Probability of dropout was estimated using a CR technique as well as a Cox model for time to dropout. Overall, non-HCC patients had a higher dropout rate from the WL than HCC patients (p < 0.0001). This was reproducible throughout all regions. In Cox regression, tumor size, model for end-stage liver disease (MELD) score and alpha fetoprotein (AFP) were associated with increased dropout risk. Multivariable analysis with CR showed that MELD score and AFP, were most influential in predicting dropout for HCC patients. The index of concordance for predicting dropout with the CR was 0.70. HCC patients appear to be advantaged in the current allocation scheme based on lower dropout rates without regard to geography. A continuous score incorporating MELD, AFP and tumor size may help to prioritize HCC patients to better equate dropout rates with non-HCC patients and equalize access.

Distribution of ceftiofur into Mannheimia haemolytica-infected tissue chambers and lung after subcutaneous administration of ceftiofur crystalline free acid sterile suspension

The objective of this study was to evaluate the penetration of ceftiofur- and desfuroylceftiofur-related metabolites (DCA) into sterile and infected tissue chambers, lung tissue and disposition of DCA in plasma across four different sacrifice days postdosing. Twelve healthy calves were utilized following implantation with tissue chambers in the paralumbar fossa. Tissue chambers in each calf were randomly inoculated with either Mannheimia haemolytica or sterile PBS. All calves were dosed with ceftiofur crystalline free acid sterile suspension (CCFA-SS) subcutaneously in the ear pinna. Calves were randomly assigned to 4 groups of 3 to be sacrificed on days 3, 5, 7 and 9 postdosing. Prior to euthanasia, plasma and tissue chamber fluid were collected, and immediately following euthanasia, lung tissue samples were obtained from four different anatomical sites DCA concentration analysis. Results of our study found that, in general, DCA concentrations followed a rank order of plasma > infected tissue chamber fluid > noninfected tissue chamber fluid > lung tissue. Data also indicated DCA concentrations remained above the therapeutic threshold of 0.2 microg/mL for plasma and chamber fluid and 0.2 microg/g for lung tissue for at least 7 days post-treatment.

Clinical Trial of the Pan-Caspase Inhibitor, IDN-6556, in Human Liver Preservation Injury

Cold ischemia/warm reperfusion (CI/WR) injury remains a problem in liver transplantation. The aim of the current study was to assess the utility of the pan-caspase inhibitor IDN-6556 on CI/WR injury during human liver transplantation. This report is a post hoc analysis of a Phase II, multi-center, randomized, placebo-controlled, double-blinded, parallel group study. Subjects were assigned to four treatment groups: Group 1 (Organ storage/flush: Placebo-Recipient: Placebo); Group 2 (Organ storage/flush: 15 microg/mL-Recipient: Placebo); Group 3 (Organ storage/flush: 5 microg/mL-Recipient: 0.5 mg/kg); and Group 4 (Organ storage/flush: 15 microg/mL-Recipient: 0.5 mg/kg). Liver cell apoptosis was assessed by serum concentrations of the apoptosis-associated CK18Asp396 ('M30') neo-epitope, TUNEL assay and caspase 3/7 immunohistochemistry. Liver injury was assessed by serum AST/ALT determinations. Serum markers of liver cell apoptosis were reduced in all groups receiving drug as compared to placebo. However, TUNEL, caspase 3/7 positive cells and serum AST/ALT levels were only consistently reduced in Group 2 (drug exposed to organ only). This reduction in serum transaminases was significant and observed across the study. In conclusion, IDN-6556 when administered in cold storage and flush solutions during liver transplantation offers local therapeutic protection against CI/WR-mediated apoptosis and injury. However, larger studies are required to confirm these observations.

Measurement of atmospheric neutrino flux consistent with tau neutrino appearance

A search for the appearance of tau neutrinos from nu(mu) <--> nu(tau) oscillations in the atmospheric neutrinos has been performed using 1489.2 days of atmospheric neutrino data from the Super-Kamiokande-I experiment. A best fit tau neutrino appearance signal of 138+/-48(stat)-32(+15)(syst) events is obtained with an expectation of 78+/-26(syst). The hypothesis of no tau neutrino appearance is disfavored by 2.4 sigma.

Penetration of ceftiofur into sterile vs. Mannheimia haemolytica-infected tissue chambers in beef calves after subcutaneous administration of ceftiofur crystalline free acid sterile suspension in the ear pinna

The effect of Mannheimia haemolytica infection on the penetration of ceftiofur and desfuroylceftiofur metabolites into tissue chambers was studied in cattle after subcutaneous administration of ceftiofur crystalline free acid sterile suspension (CCFA-SS). Four tissue chambers were implanted subcutaneously in each of 12 calves. Approximately 45 days after implantation, two chambers were inoculated with M. haemolytica (10(6) colony-forming units per chamber) while the remaining two chambers were inoculated with sterile phosphate-buffered saline. Twenty-four hours after inoculation, CCFA-SS was administered subcutaneously in the middle third of the caudal ear pinna of each calf. Chamber fluid and blood samples were collected at predetermined times for 10 days following dosing and analyzed for ceftiofur and desfuroylceftiofur metabolites by high-performance liquid chromatography. Concentrations of ceftiofur and desfuroylceftiofur metabolites in plasma and tissue chamber fluid remained above a threshold of 0.2 microg/mL for at least 8 days. Infected tissue chamber fluid concentrations of ceftiofur and desfuroylceftiofur metabolites were significantly higher than those in non-infected tissue chamber fluid, which correlated with significantly higher total protein concentration in infected tissue chambers. These results indicate that single subcutaneous administration of CCFA-SS at 6.6 mg/kg can be expected to provide effective therapy of susceptible bacterial infections for a period of at least 1 week.

Evidence for an oscillatory signature in atmospheric neutrino oscillations

Muon neutrino disappearance probability as a function of neutrino flight length L over neutrino energy E was studied. A dip in the L/E distribution was observed in the data, as predicted from the sinusoidal flavor transition probability of neutrino oscillation. The observed L/E distribution constrained nu(micro)<-->nu(tau) neutrino oscillation parameters; 1.9x10(-3)<Deltam(2)<3.0x10(-3) eV(2) and sin((2)2theta>0.90 at 90% confidence level.

Limits on the neutrino magnetic moment using 1496 days of Super-Kamiokande-I solar neutrino data

A search for a nonzero neutrino magnetic moment has been conducted using 1496 live days of solar neutrino data from Super-Kamiokande-I. Specifically, we searched for distortions to the energy spectrum of recoil electrons arising from magnetic scattering due to a nonzero neutrino magnetic moment. In the absence of a clear signal, we found micro(nu)</=(3.6x10(-10))micro(B) at 90% C.L. by fitting to the Super-Kamiokande day-night spectra. The fitting took into account the effect of neutrino oscillation on the shapes of energy spectra. With additional information from other solar neutrino and KamLAND experiments constraining the oscillation region, a limit of micro(nu)</=(1.1x10(-10))micro(B) at 90% C.L. was obtained.

Steroid elimination 24 hours after liver transplantation using daclizumab, tacrolimus, and mycophenolate mofetil

BACKGROUND

Corticosteroids have long been a cornerstone of orthotopic liver transplant (OLTx) immunosuppression. Newer, more potent, agents have successfully allowed for more rapid tapering and discontinuation of corticosteroids in OLTx recipients. We hypothesize that corticosteroids can be safely avoided after the first postoperative day (POD) using these newer agents.

METHODS

Thirty adult OLTx recipients were prospectively enrolled in a randomized open-label, institutional review board-approved protocol. Fifteen patients (group A) received our standard regimen of tacrolimus, mycophenolate mofetil, and corticosteroids, and 15 patients (group B) received daclizumab, 2 mg/kg on POD 0 and 14, with tacrolimus, mycophenolate mofetil, and corticosteroids on POD 0 and 1 and then discontinuation. In both groups, mycophenolate mofetil was tapered off between 3 and 4 months after OLTx. Bone mineral densitometry was performed at 1, 3, and 6 months after OLTx. Quantitative hepatitis C virus (HCV) polymerase chain reaction was obtained at days 0, 7, 14, 21, and 28. Retransplant recipients, patients with autoimmune hepatitis, or status 1 or 2A patients were excluded.

RESULTS

Patient and graft survival rates were 93% (group A) and 100% (group B) with mean follow-up of 18 months. Patients in group B had more rejection diagnosed (25%) compared with group A (6.7%). Yet, the incidence of biopsy-proven acute rejection requiring steroid therapy was 6.7% in both groups. Hispanic race was common in groups A and B (87% and 74%). A total of six biopsies were performed in group B, with three patients having mild rejection responding to an increase in tacrolimus without the need for corticosteroids. One patient in group B was switched to cyclosporine for severe neurotoxicity and remains on monotherapy with normal graft function. No patient in either group developed a requirement for additional antihypertensive medication. Likewise, there were no patients with new-onset diabetes. The bone mineral densitometry was higher in group B at every time point but did not reach statistical significance. Serum cholesterol level was significantly (P=0.03) lower in group B at 6 months after OLTx. Serum triglycerides were also lower, but the difference was not significant. Quantitative polymerase chain reaction for HCV-positive patients (group A, n=7; group B, n=8) frequently increased after OLTx. There was no correlative decrease associated with daclizumab. At present, two patients in group A have documented HCV recurrence.

CONCLUSION

Corticosteroids can be safely avoided after POD 1 with the current regimen. With early follow-up, there is no difference in hypertension or diabetes or bone density. Lipid panels tended to be lower in patients who were not on corticosteroids. Longer term follow-up will be needed to demonstrate the potential advantage of corticosteroid avoidance in regard to hypertension, diabetes, and possibly HCV recurrence.

Phenobarbital-responsive nuclear translocation of the receptor CAR in induction of the CYP2B gene

The constitutively active receptor (CAR) transactivates a distal enhancer called the phenobarbital (PB)-responsive enhancer module (PBREM) found in PB-inducible CYP2B genes. CAR dramatically increases its binding to PBREM in livers of PB-treated mice. We have investigated the cellular mechanism of PB-induced increase of CAR binding. Western blot analyses of mouse livers revealed an extensive nuclear accumulation of CAR following PB treatment. Nuclear contents of CAR perfectly correlate with an increase of CAR binding to PBREM. PB-elicited nuclear accumulation of CAR appears to be a general step regulating the induction of CYP2B genes, since treatments with other PB-type inducers result in the same nuclear accumulation of CAR. Both immunoprecipitation and immunohistochemistry studies show cytoplasmic localization of CAR in the livers of nontreated mice, indicating that CAR translocates into nuclei following PB treatment. Nuclear translocation of CAR also occurs in mouse primary hepatocytes but not in hepatocytes treated with the protein phosphatase inhibitor okadaic acid. Thus, the CAR-mediated transactivation of PBREM in vivo becomes PB responsive through an okadaic acid-sensitive nuclear translocation process.

Effect of kangaroo care on sleep time for neonates

PURPOSE

To determine the change in behavioral state and physiologic parameters due to Kangaroo Care (K Care).

METHOD

A quasi-experimental design using a pretest-posttest with neonates serving as their own controls for 4 episodes of 1 hour each: Pre K Care, K Care and Post K Care. Twenty neonate-parent dyads participated. RespiTrace PT Non-invasive Monitoring system was used to record heart and respiratory rate and oxygen saturation. Behavioral state was derived from analyzing RespiTrace PT cardiorespiratory data as well as observation criteria.

FINDINGS

There was a significant increase in sleep time for the neonates during K Care as compared to when they were not receiving K Care. The neonates exhibited less agitation, apnea, and bradycardia episodes and maintained stable oxygen saturation during K Care.

CONCLUSION

K Care is safe even for very small neonates and is well tolerated. The stability of the preterm infants receiving K Care documents the need to incorporate it into standards of care.

Hepatitis C virus reinfection in orthotopic liver transplant patients with or without concomitant hepatitis B infection

Although recurrence of hepatitis C virus (HCV) in orthotopic liver transplant (OLT) patients is frequent, the relationship between HCV recurrence and graft pathology, particularly in patients who also have a history of hepatitis B virus (HBV), is unclear. The recurrence of HCV after OLT was determined by reverse transcriptase-nested polymerase chain reaction (RT-PCR) in the sera and livers of 41 patients with OLT, 32 of whom underwent transplants for HCV or HBV-related disease. Results were compared with liver function tests, liver histology (including HBV immunohistochemistry), and antibody status. HCV PCR was more frequently positive in OLT patients with a history of HCV only (59%) than in those with a history of both HCV and HBV (41%) or no history of viral infection (2%). Recurrent HCV (60% overall) was associated with mild elevation of liver function tests and mild to moderate hepatitis. In patients who underwent transplants for both HCV and HBV disease, hepatitis on biopsy was more frequently associated with recurrent HBV than with recurrent HCV. We conclude that graft reinfection with HCV, which is frequent in OLT patients with or without HBV recurrence, is usually associated with only mild to moderate hepatitic changes compatible with graft survival.

Synthesis and characterization of hydroxylated polychlorinated biphenyls (PCBs) identified in human serum

Hydroxylated polychlorinated biphenyls (PCBs) have been identified in wildlife and human samples. Most of these compounds are highly chlorinated (penta-hepatachloro) and contain a single meta- or para-hydroxyl group. Using the Cadogan coupling procedure, the following hydroxy-PCBs congeners were synthesized: 2,3,3',4',5-pentachloro-4-biphenylol, 2,3',4,4',5-pentachloro-3-biphenylol, 2',3,3',4',5-pentachloro-4-biphenylol, 2,2',3',4,4'-pentachloro-3-biphenylol, 2,2',3,3',4',5-pentachloro-4-biphenylol, 2,2',3',4,4',5-hexachloro-3-biphenylol, 2,2',3,4',5,5'-hexachloro-4-biphenylol, 2,2',3,3',4',5,5'-heptachloro-4-biphenylol, 2,2',3',4,4',5,5'-hepatachloro-3-biphenylol, 2,2',3,4',5,5',6-heptachloro-4-biphenylol. Many of these compounds have been detected as residues in human serum and current studies are investigating their activities as agonists and antagonists for several endocrine-mediated responses.