Measurement of muon neutrino quasielastic scattering on carbon

The observation of neutrino oscillations is clear evidence for physics beyond the standard model. To make precise measurements of this phenomenon, neutrino oscillation experiments, including MiniBooNE, require an accurate description of neutrino charged current quasielastic (CCQE) cross sections to predict signal samples. Using a high-statistics sample of nu_(mu) CCQE events, MiniBooNE finds that a simple Fermi gas model, with appropriate adjustments, accurately characterizes the CCQE events observed in a carbon-based detector. The extracted parameters include an effective axial mass, M_(A)(eff)=1.23+/-0.20 GeV, that describes the four-momentum dependence of the axial-vector form factor of the nucleon, and a Pauli-suppression parameter, kappa=1.019+/-0.011. Such a modified Fermi gas model may also be used by future accelerator-based experiments measuring neutrino oscillations on nuclear targets.

Measurement of the nucleon strange-antistrange asymmetry at next-to-leading order in QCD from NuTeV Dimuon data

We present a new measurement of the difference between the nucleon strange and antistrange quark distributions from dimuon events recorded by the NuTeV experiment at Fermilab. This analysis is the first to use a complete next to leading order QCD description of charm production from neutrino scattering. Dimuon events in neutrino deep inelastic scattering allow direct and independent study of the strange and antistrange content of the nucleon. We find a positive strange asymmetry with a significance of 1.6sigma. We also report a new measurement of the charm mass.

Search for electron neutrino appearance at the Delta m2 approximately 1 eV2 scale

The MiniBooNE Collaboration reports first results of a search for nu e appearance in a nu mu beam. With two largely independent analyses, we observe no significant excess of events above the background for reconstructed neutrino energies above 475 MeV. The data are consistent with no oscillations within a two-neutrino appearance-only oscillation model.

Improvements in hepatic parenchymal transection for living related liver donor

INTRODUCTION

To eliminate mortality and morbidity risk in living related liver donors, we developed a new surgical technique to resect hepatic parenchyma using an ultrasonic surgical aspirator in association with a monopolar floating ball cautery.

METHODS

We performed 17 right hepatectomies and 2 left hepatectomies using this technique. We performed a retrospective analysis of perioperative mortality, length of hospitalization (LOS), blood transfused during surgery (IBT), intraoperative blood lost (IBL), biliary complications (BC), and aspartate aminotransferase (AST)/alanine aminotransferase (ALT) peak in the first postoperative week. This group of patients (Group A) was compared, using the analysis of variance (ANOVA) test (P < .05) with 2 different groups of 19 patients: Group B with liver neoplasms that had the same technique as Group A, and Group C wherein a crushing clamp technique was used.

RESULTS

All of the analyzed variables showed significative statistical differences, especially between Group A and Group C (IBL, P < .000; IBT, P < .006; LOS, P < .028; BC, P < .000; AST peak, P < .041; and ALT peak, P < .023).

DISCUSSION

The association of these 2 techniques seems to reduce the LOS, and the need for intraoperative blood transfusions. Moreover, the surgical complications (biliary leaks) and the postoperative parenchymal cytonecrosis seem to be less using this technique.

Tacrolimus for Primary Liver Transplantation: 12 to 15 Years Actual Follow-Up With Safety Profile

BACKGROUND

Tacrolimus has been increasingly used for liver transplantation during the last decade. The drug has immunological advantages in short- to medium-term follow-up. However, data on longitudinal follow-up are lacking.

AIM

The aim of the present report was to examine the impact of tacrolimus in primary adult and pediatric liver transplantation (LTx) patients.

MATERIAL AND METHOD

One thousand consecutive primary LTx patients were performed under tacrolimus between August 1989 and December 1992 were followed up until August 2004. Mean follow-up was 13.4 +/- 0.92 (range, 11.7-15) years. There were 600 males and 400 females with a mean age of 42.6 +/- 20.2 years. There were 166 children (age 18 years or younger) and 834 adults, of whom 204 were older than 60 years (seniors).

RESULTS

Four hundred ninety-seven (49.7%) patients died in the follow-up period. The overall 15-year actuarial patient survival rate was 51.4%. The survival rate for children was significantly better (81.3%) compared with adults (47.5%) and seniors (36.4%) (P = .0001). One hundred fifty-one patients received a second LTx, 22 patients received a third LTx, and 4 patients received a fourth LTx. Over all 15 years the actuarial graft survival rate was 46.1%. At last follow-up, 69.1% of patients were off steroids. The majority of late deaths were due to age-related complications, recurrence of disease, and De novo cancers.

CONCLUSION

The data on longitudinal follow-up have shown actuarial survival for children to be significantly better than in adults and seniors. Graft loss from immunological causes are rare even with long-term follow-up.

Prediction of different mandibular activities by EMG signal levels

The purpose of this study was to make observations of electromyographic (EMG) signal levels from a group of individuals to describe different mandibular tasks and use them as predictors of these activities. The sample consisted of 22 volunteer subjects (12 women and 10 men) with mean values for age, weight and height of 29.3 years, 69 kg and 168 cm respectively. Three separate recording sessions were performed for each subject. During each session the subjects were asked to perform different voluntary mandibular tasks. The EMG activity for each task was recorded from the anterior temporalis (T(a)) and masseter muscles (M(m)) bilaterally. The EMG recordings were related to task, session, task-session interaction, gender, age, weight and height using SAS version 6.12. The EMG data from the four muscles were considered as covariates to classify tasks. Overall, 78% of the group tasks were correctly classified. When the masticatory activities were classified as high and low EMG signal level group, the overall classification rate improved with an accuracy of 88%, sensitivity of 86%, specificity of 88%, positive predictive value of 76% and negative predictive value of 94%. The tasks, sessions, task-session interactions, gender, age, weight and height did not have any significant effect on the EMG recordings. It can be concluded that distinguishing among different mandibular tasks of a subject can be achieved when the individual EMG signal levels were compared with the EMG signal levels of subjects that were used to describe different mandibular activities.

Real-time monitoring of acute liver-allograft rejection using the Banff schema

BACKGROUND

The Banff schema is the internationally accepted standard for grading acute liver-allograft rejection, but it has not been prospectively tested.

METHODS

Complete Banff grading was prospectively applied to 2,038 liver-allograft biopsies from 901 adult tacrolimus-treated primary hepatic allograft recipients between August 1995 and September 2001. Histopathologic data was melded with demographic, clinical, and laboratory data into a database on an ongoing basis using locally developed software.

RESULTS

Acute rejection developed in 575 of 901 (64%) patients and the worst grade was mild in 422 of 575 (73%). At least one episode of moderate or severe acute rejection developed in 153 of 901 (17%) patients and most episodes, irrespective of severity, occurred within the first year after transplantation. Patients with moderate or severe acute rejection showed higher alanine aminotransferase (P =0.007) and aspartate aminotransferase ( P=0.07) levels and were more likely to develop perivenular fibrosis on follow-up biopsies (P =0.001) and graft failure from acute or chronic rejection ( P=0.004) than those with mild rejection. Regardless of severity, 80% of patients with acute rejection did not develop significant fibrosis in follow-up biopsies, and graft failure from acute or chronic rejection occurred in only 11 of 901 (1%) allografts.

CONCLUSIONS

Most acute-rejection episodes are mild and do not lead to clinically significant architectural sequelae. When tested prospectively under real-life and -time conditions, the Banff schema can be used to identify those few patients who are potentially at risk for more significant problems. Creation, capture, and integration of non-free text, or "digital," pathology data can be used to prospectively conduct outcomes-based research in transplantation.

Search for nu(mu)-->nu(e) and nu(mu)-->nu(e) oscillations at NuTeV

Limits on nu(mu)-->nu(e) and nu(mu)-->nu(e) oscillations are extracted using the NuTeV detector with sign-selected nu(mu) and nu(mu) beams. In nu(mu) mode, for the case of sin(2)2alpha = 1, Delta(m)(2)>2.6 eV(2) is excluded, and for Delta(m)(2)>>1000 eV(2), sin(2)2alpha>1.1 x 10(-3). The NuTeV data exclude the high Delta(m)(2) end of nu(mu)-->nu(e) oscillation parameters favored by the LSND experiment without the need to assume that the oscillation parameters for nu and nu are the same. We present the most stringent experimental limits for nu(mu)(nu(mu))-->nu(e)(nu(e)) oscillations in the large Delta(m)(2) region.

Precise determination of electroweak parameters in neutrino-nucleon scattering

The NuTeV Collaboration has extracted the electroweak parameter sin(2)theta(W) from the measurement of the ratios of neutral current to charged current nu and (-)nu cross sections. Our value, sin(2)theta((on-shell))(W) = 0.2277 +/- 0.0013(stat) +/- 0.0009(syst), is 3 standard deviations above the standard model prediction. We also present a model independent analysis of the same data in terms of neutral-current quark couplings.

Extraction of R = sigma(L)/sigma(T) from CCFR nu(mu)-Fe and nu(mu)-Fe differential cross sections

We report on the extraction of R = sigma(L)/sigma(T) from CCFR nu(mu)-Fe and nu(mu)-Fe differential cross sections. The CCFR differential cross sections do not show the deviations from the QCD expectations that are seen in the CDHSW data at very low and very high x. R as measured in nu(mu) scattering is in agreement with R as measured in muon and electron scattering. All data on R for Q(2)>1 GeV(2) are in agreement with a NNLO QCD calculation which uses NNLO parton distribution functions and includes target mass effects. We report on the first measurements of R in the low x and Q(2)<1 GeV(2) region (where an anomalous large rise in R for nuclear targets has been observed by the HERMES Collaboration).

Search for the lepton family number violating process nu(mu)e(-) --> mu(-)nu(e)

The NuTeV experiment at Fermilab has used a sign-selected neutrino beam to perform a search for the lepton number violating process nu(mu)e(-)-->mu(-)nu(e), and to measure the cross section of the standard model inverse muon decay process nu(mu)e(-)-->mu(-)nu(e). NuTeV measures the inverse muon decay asymptotic cross-section slope sigma/E to be (13.8 +/- 1.2 +/- 1.4) x 10(-42) cm(2)/GeV. The experiment also observes no evidence for lepton number violation and places one of the most restrictive limits on the cross-section ratio sigma(nu(mu)e(-)-->mu(-)nu(e))/sigma(nu(mu)e(-)-->mu(-)nu(e)) < or = 1.7% at 90% C.L. for V-A couplings and < or = 0.6% for scalar couplings.

Observation of an anomalous number of dimuon events in a high energy neutrino beam

A search for long-lived neutral particles ( N0's) with masses above 2.2 GeV/c(2) that decay into at least one muon has been performed using an instrumented decay channel at the NuTeV experiment at Fermilab. Data were examined for particles decaying into the final states mumu, mu(e), and mu(pi). Three mumu events were observed over an expected standard model background of 0.069+/-0.010 events; no events were observed in the other modes.

Reasons for long-term use of steroid in primary adult liver transplantation under tacrolimus

BACKGROUND

Tacrolimus is a potent immunosuppressive agent that provides higher freedom from acute and chronic rejection than cyclosporine after liver transplantation (LTx). Initially, a steroid-free state was observed in about 70% of patients at 1 year; this did not change over the next 5 years. The present study identifies the various reasons why the remaining 30% of adult patients still require steroids even after 5 years after successful LTx.

METHOD

Eight hundred thirty-four consecutive patients who underwent LTx between August 1989 and December 1992 were included in this study. Four hundred ninety-nine patients were alive in January 1999 and were available for this study. The dose of steroid and the reason for steroid use were retrospectively determined from the clinical records.

RESULTS

Three hundred sixty-five patients (73.1%) were off steroid, whereas 134 patients (26.9%) were receiving prednisone (mean dose was 6.4+/-3.7 mg/day) at the time of the study. Four hundred and eight-four patients (97%) were off prednisone at some time after LTx; however, in 119 (23.8%) patients, steroids were reintroduced. Fifteen patients (3%) continued to receive prednisone; eight receive prednisone due to reluctance of the local physician to withdraw the medication; in five patients, the prednisone was not withdrawn because these patients were on cyclosporine; in the remaining two patients, repeated attempts to withdraw steroid resulted in a rise in liver function test. In the 49 (36.6%) of 119 patients in whom the steroid was reintroduced, it was restarted secondary to pathologically proven or clinically suspected rejection (group I). In five patients steroid was reintroduced for abnormal liver function after being off immunosuppression for treatment of a posttransplantation lymphoproliferative disorder. Six patients were noncompliant with their immunosuppressive medication, and the steroid was reintroduced to control rejection. Steroids were reintroduced in 30 patients (22.4%) for recurrence of original disease: primary biliary cirrhosis (n= 19), sclerosing cholangitis (n=6), and autoimmune hepatitis (n=5) (group II). In 24 patients (20.2%), steroids were reintroduced to lower the dose of tacrolimus secondary to nephrotoxicity. Six of these patients received kidney transplantation (group III). In 16 patients (13.4%) the steroid was reintroduced for concomitant medical problems, consisting of ulcerative/Crohn's colitis (n=6), adrenal insufficiency (n=5), hematological disorders (n=3), dermatitis (n=1), and rheumatoid arthritis (n=1) (group IV).

CONCLUSION

Ninety-seven percent of patients under tacrolimus were weaned off steroid; however, 23.8% required steroid reintroduction for late rejection, recurrence of autoimmune process(es), renal impairment, or the concomitant presence of other medical conditions. Although the use of other immunosuppressive agents may reduce the rate of reintroduction of steroid, long-term sustained freedom from steroid may not be possible in all patients under tacrolimus secondary to these conditions.

First measurement of the low- x, low- Q(2) structure function F(2) in neutrino scattering

A new structure function analysis of CCFR deep inelastic nu-N and nu-N scattering data is presented for previously unexplored kinematic regions down to Bjorken x = 0.0045 and Q(2) = 0.3 GeV(2). Comparisons to charged lepton scattering data from NMC and E665 experiments are made and the behavior of the structure function F(2)(nu)2 is studied in the limit Q(2)-->0.

Reasons why some children receiving tacrolimus therapy require steroids more than 5 years post liver transplantation

Tacrolimus is a potent immunosuppressive agent and has been used in liver transplantation (LTx) for nearly a decade. More than 70% of children can be maintained on tacrolimus monotherapy, without steroids, by the end of 1 yr post-Tx. This freedom from steroids does not appear to change significantly in subsequent years. The use of steroids has obvious metabolic and cosmetic disadvantages, besides affecting linear growth in children. The present study identifies why some children still require steroid therapy after successful LTx. One hundred and sixty-six consecutive pediatric patients who had undergone primary LTx between October 1989 and December 1992, were included in this study. Follow-up ranged from 6 to 9 yr (mean 7.5 +/- 0.8 yr). One hundred and forty-one children were alive in November 1998 and these patients constituted the study group. Their current rate of prednisone use, reason for prednisone use, and prednisone dose were examined retrospectively. Of the 141 patients, 139 (98.5%) had stopped taking steroids at some time-point after LTx. Thirteen patients (9%) were off immunosuppression altogether (group I), 97 were undergoing tacrolimus monotherapy (group II), and the remaining 31 were receiving therapy with steroids and tacrolimus (group III). The mean prednisone dose at the last follow-up was 6.5 +/- 4.9 mg/day (median 5.0 mg/day). In group III, two children were never weaned off steroids because of inadequate follow-up (both lived outside the country), and the remaining 29 children completely stopped steroid therapy at some time-point after LTx; however, prednisone was re-introduced for clinically suspected or biopsy-proven rejection in 24. Seven children in group III had completely stopped immunosuppressive therapy either as part of an immunosuppression reduction protocol (n = 3) or for suspected or proven post-transplant lymphoproliferative disorder (PTLD) (n = 4). In eleven of the 18 children in group III, requirement of steroid for rejection was thought to be related, in part, to non-compliance. In three children in group III, steroids were re-introduced for renal dysfunction, and two of these patients subsequently received a kidney Tx. In one child with cerebral ischemia, steroids were used to reduce brain edema, and another child had features of auto-immune hepatitis. Hence, almost all children can be weaned off steroids when tacrolimus is used as primary immunosuppression after primary LTx. However, approximately 22% of children may need re-institution of steroids because of late acute rejection or renal dysfunction. The concomitant use of other non-steroidal immunosuppressive agents with tacrolimus may further reduce the dose and rate of steroid use.

Measurements of F2 and xF(nu)(3) - xF(nu;)(3) from CCFR nu(mu)-Fe and nu;(mu)-Fe Data in a Physics Model-Independent Way

We report on the extraction of the structure functions F2 and DeltaxF(3) = xF(nu)(3)-xF(nu;)(3) from CCFR nu(mu)-Fe and nu;(mu)-Fe differential cross sections. The extraction is performed in a physics model-independent (PMI) way. This first measurement of DeltaxF(3), which is useful in testing models of heavy charm production, is higher than current theoretical predictions. The ratio of the F2 (PMI) values measured in nu(mu) and mu scattering is in agreement (within 5%) with the predictions of next-to-leading-order parton distribution functions using massive charm production schemes, thus resolving the long-standing discrepancy between the two sets of data.

Fibrolamellar hepatocellular carcinoma: pre- and posttherapy evaluation with CT and MR imaging

PURPOSE

To determine the features of advanced hepatic and extrahepatic fibrolamellar hepatocellular carcinomas (HCCs) and their effects on immediate surgical management and tumor recurrence.

MATERIALS AND METHODS

Thirty-one patients with fibrolamellar HCC underwent pretherapy computed tomography (CT); 11 underwent pretherapy magnetic resonance (MR) imaging. All 40 patients underwent posttherapy CT; four, follow-up MR imaging. Imaging, surgical, and histopathologic findings were correlated.

RESULTS

Twenty-five (81%) patients had solitary tumors (mean maximum diameter, 13 cm). Thirteen (42%) patients had intrahepatic biliary obstruction; 27 (87%) patients had involvement of the portal or hepatic veins. Thirteen (42%) had extrahepatic tumor spread, nine (29%) had distant metastases on pretherapy images, and 20 (65%) had lymphadenopathy. Thirty-two (80%) of 40 patients underwent exploration surgery; curative resection was attempted in 25 (62%), including four patients who underwent liver transplantation. Only 17 patients were considered to have had hepatic and extrahepatic tumors completely excised. Tumor recurred in all eight of the 17 patients who had extrahepatic disease at pretherapy CT and in four of the seven patients who seemed to have tumor limited to the liver. A combination of repeat tumor resection and adjuvant chemotherapy resulted in prolonged tumor-free survival in some cases.

CONCLUSION

Fibrolamellar HCC frequently demonstrates aggressive local invasion and nodal and distant metastases. Pretherapy and follow-up imaging are important for staging, surveillance, and optimal management. Aggressive surgical resection may be helpful to control fibrolamellar HCC and to prolong survival in appropriately selected cases.

Long-term survival after liver transplantation in 4,000 consecutive patients at a single center

OBJECTIVE

To evaluate the long-term survival outcomes of a large cohort of liver transplant recipients and to identify static and changing factors that influenced these outcomes over time.

SUMMARY BACKGROUND DATA

Liver transplantation has been accepted as a therapeutic option for patients with end-stage liver disease since 1983, with continual improvements in patient survival as a result of advances in immunosuppression and medical management, technical achievements, and improvements in procurement and preservation. Although many reports, including registry data, have delineated short-term factors that influence survival, few reports have examined factors that affect long-term survival after liver transplantation.

METHODS

Four thousand consecutive patients who underwent liver transplantation between February 1981 and April 1998 were included in this analysis and were followed up to March 2000. The effect of donor and recipient age at the time of transplantation, recipient gender, diagnosis, and year of transplantation were compared. Rates of retransplantation, causes of retransplantation, and cause of death were also examined.

RESULTS

The overall patient survival for the entire cohort was 59%; the actuarial 18-year survival was 48%. Patient survival was significantly better in children, in female recipients, and in patients who received transplants after 1990. The rates of retransplantation for acute or chronic rejection were significantly lower with tacrolimus-based immunosuppression. The risk of graft failure and death was relatively stable after the first year, with recurrence of disease, malignancies, and age-related complications being the major factors for loss.

CONCLUSION

Significantly improved patient and graft survival has been observed over time, and graft loss from acute or chronic rejection has emerged as a rarity. Age-related and disease-related causes of graft loss represent the greatest threat to long-term survival.

Liver transplantation for Wilson's disease: a single-center experience

Wilson's disease is a hereditary defect in copper excretion leading to the accumulation of copper in the tissues, with subsequent tissue damage. The most serious sequela is that of progressive central nervous system involvement. The use of orthotopic liver transplantation (OLT) has been controversial for those patients with neurological symptoms attributed to Wilson's disease. The aim of this study is to determine the effectiveness of OLT for patients with Wilson's disease, including those with neurological involvement attributed to copper accumulation in the central nervous system. OLT was performed in 45 patients (19 men [42.2%], 26 women [57.8%]) with Wilson's disease between 1971 and 1993 who were followed up for at least 4 years. The age at diagnosis of Wilson's disease ranged from 3 to 41 years (mean, 17.7 +/- 7.4 years). The age at OLT ranged from 8 to 52 years (mean, 22.3 +/- 9.4 years). Nineteen patients (42.2%) were aged younger than 18 years at OLT. The indications for OLT included chronic hepatic failure in 15 patients (33.3%) and fulminant (FHF) or subfulminant hepatic failure in 30 patients (66. 6%). All but 1 of the 19 pediatric patients (94.7%) were in the latter group. Twenty-five patients (55.5%) were receiving D-penicillamine, 9 patients for more than 1 year; none of the patients treated long term presented as FHF. Thirty-three patients (73.3%) survived more than 5 years after OLT. Fourteen patients (31%) died during the posttransplantation period; 7 of the 14 patients (50%) were aged younger than 18 years. Twelve patients died during the first 3 months after OLT of complications of disease and surgery, 10 of whom underwent transplantation for FHF. The other 2 patients died 6 and 9 years after transplantation of infectious problems. Eleven patients (24.4%) required retransplantation because of a primary nonfunctioning graft (n = 6), chronic rejection (n = 4), and hepatic artery thrombosis (n = 1). Seventeen patients (37.7%) presented with neurological abnormalities; 14 patients with Wilsonian neurological manifestations and 3 patients with components of increased intracranial pressure. Ten of the 13 surviving patients with hepatic insufficiency and neurological abnormalities at OLT showed significant neurological improvement. Our experience shows OLT is a life-saving procedure in patients with end-stage Wilson's disease and is associated with excellent long-term survival. The neurological manifestation of the disease can improve significantly after OLT. Earlier transplantation in patients with an unsatisfactory response to medical treatment may prevent irreversible neurological deterioration and less satisfactory improvement after OLT.