Determination of the ^{27}Al Neutron Distribution Radius from a Parity-Violating Electron Scattering Measurement

We report the first measurement of the parity-violating elastic electron scattering asymmetry on ^{27}Al. The ^{27}Al elastic asymmetry is A_{PV}=2.16±0.11(stat)±0.16(syst)  ppm, and was measured at ⟨Q^{2}⟩=0.02357±0.00010  GeV^{2}, ⟨θ_{lab}⟩=7.61°±0.02°, and ⟨E_{lab}⟩=1.157  GeV with the Q_{weak} apparatus at Jefferson Lab. Predictions using a simple Born approximation as well as more sophisticated distorted-wave calculations are in good agreement with this result. From this asymmetry the ^{27}Al neutron radius R_{n}=2.89±0.12  fm was determined using a many-models correlation technique. The corresponding neutron skin thickness R_{n}-R_{p}=-0.04±0.12  fm is small, as expected for a light nucleus with a neutron excess of only 1. This result thus serves as a successful benchmark for electroweak determinations of neutron radii on heavier nuclei. A tree-level approach was used to extract the ^{27}Al weak radius R_{w}=3.00±0.15  fm, and the weak skin thickness R_{wk}-R_{ch}=-0.04±0.15  fm. The weak form factor at this Q^{2} is F_{wk}=0.39±0.04.

Precision Measurement of the Beam-Normal Single-Spin Asymmetry in Forward-Angle Elastic Electron-Proton Scattering

A beam-normal single-spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable related to the imaginary part of the two-photon exchange process. We report a 2% precision measurement of the beam-normal single-spin asymmetry in elastic electron-proton scattering with a mean scattering angle of θ_{lab}=7.9° and a mean energy of 1.149 GeV. The asymmetry result is B_{n}=-5.194±0.067(stat)±0.082 (syst) ppm. This is the most precise measurement of this quantity available to date and therefore provides a stringent test of two-photon exchange models at far-forward scattering angles (θ_{lab}→0) where they should be most reliable.

Distinct Roles for Intracellular and Extracellular Lipids in Hepatitis C Virus Infection

Hepatitis C is a chronic liver disease that contributes to progressive metabolic dysfunction. Infection of hepatocytes by hepatitis C virus (HCV) results in reprogramming of hepatic and serum lipids. However, the specific contribution of these distinct pools of lipids to HCV infection remains ill defined. In this study, we investigated the role of hepatic lipogenesis in HCV infection by targeting the rate-limiting step in this pathway, which is catalyzed by the acetyl-CoA carboxylase (ACC) enzymes. Using two structurally unrelated ACC inhibitors, we determined that blockade of lipogenesis resulted in reduced viral replication, assembly, and release. Supplementing exogenous lipids to cells treated with ACC inhibitors rescued HCV assembly with no effect on viral replication and release. Intriguingly, loss of viral RNA was not recapitulated at the protein level and addition of 2-bromopalmitate, a competitive inhibitor of protein palmitoylation, mirrored the effects of ACC inhibitors on reduced viral RNA without a concurrent loss in protein expression. These correlative results suggest that newly synthesized lipids may have a role in protein palmitoylation during HCV infection.

Imaging of the Cytoskeleton Using Live and Fixed Drosophila Tissue Culture Cells

In recent years, the convergence of multiple technologies and experimental approaches has led to the expanded use of cultured Drosophila cells as a model system. Their ease of culture and maintenance, susceptibility to RNA interference, and imaging characteristics have led to extensive use in both traditional experimental approaches as well as high-throughput RNAi screens. Here we describe Drosophila S2 cell culture and preparation for live-cell and fixed-cell fluorescence microscopy and scanning electron microscopy.

First determination of the weak charge of the proton

The Q(weak) experiment has measured the parity-violating asymmetry in ep elastic scattering at Q(2)=0.025(GeV/c)(2), employing 145 μA of 89% longitudinally polarized electrons on a 34.4 cm long liquid hydrogen target at Jefferson Lab. The results of the experiment's commissioning run, constituting approximately 4% of the data collected in the experiment, are reported here. From these initial results, the measured asymmetry is A(ep)=-279±35 (stat) ± 31 (syst) ppb, which is the smallest and most precise asymmetry ever measured in ep scattering. The small Q(2) of this experiment has made possible the first determination of the weak charge of the proton Q(W)(p) by incorporating earlier parity-violating electron scattering (PVES) data at higher Q(2) to constrain hadronic corrections. The value of Q(W)(p) obtained in this way is Q(W)(p)(PVES)=0.064±0.012, which is in good agreement with the standard model prediction of Q(W)(p)(SM)=0.0710±0.0007. When this result is further combined with the Cs atomic parity violation (APV) measurement, significant constraints on the weak charges of the up and down quarks can also be extracted. That PVES+APV analysis reveals the neutron's weak charge to be Q(W)(n)(PVES+APV)=-0.975±0.010.

Development and validation of an assessment of adult educators' reading instructional knowledge

The purpose of this paper is to describe briefly the development and utility of the Assessment of Reading Instructional Knowledge-Adults (ARIK-A), the only nationally normed (n = 468) measure of adult reading instructional knowledge, created to facilitate professional development of adult educators. Developmental data reveal reliabilities ranging from 0.73 to 0.85 for five ARIK-A scales (alphabetics, fluency, vocabulary, comprehension, and assessment) and 0.91 for the composite score; factor analytic data and expert review provide support for construct validity as well. Information on how to use the ARIK-A to determine mastery and relative standing is presented. With two alternate forms, the ARIK-A is a promising and needed tool for adult education practitioners within continuing education and professional development contexts.

Measurement of the parity-violating asymmetry in inclusive electroproduction of π- near the Δ0 resonance

The parity-violating (PV) asymmetry of inclusive π- production in electron scattering from a liquid deuterium target was measured at backward angles. The measurement was conducted as a part of the G0 experiment, at a beam energy of 360 MeV. The physics process dominating pion production for these kinematics is quasifree photoproduction off the neutron via the Δ0 resonance. In the context of heavy-baryon chiral perturbation theory, this asymmetry is related to a low-energy constant d(Δ)- that characterizes the parity-violating γNΔ coupling. Zhu et al. calculated d(Δ)- in a model benchmarked by the large asymmetries seen in hyperon weak radiative decays, and predicted potentially large asymmetries for this process, ranging from A(γ)-=-5.2 to +5.2  ppm. The measurement performed in this work leads to A(γ)-=-0.36±1.06±0.37±0.03  ppm (where sources of statistical, systematic and theoretical uncertainties are included), which would disfavor enchancements considered by Zhu et al. proportional to V(ud)/V(us). The measurement is part of a program of inelastic scattering measurements that were conducted by the G0 experiment, seeking to determine the N-Δ axial transition form factors using PV electron scattering.

Verification of setup errors in external beam radiation therapy using electronic portal imaging

The objective of this study was to conduct an audit on QA aspects of treatment delivery by the verification of the treatment fields′ position on different days to document the efficiency of immobilization methods and reproducibility of treatment. A retrospective study was carried out on 60 patients, each 20 treated for head and neck, breast, and pelvic sites; and a total of 506 images obtained by electronic portal imaging device (EPID) were analyzed. The portal images acquired using the EPID systems attached to the Varian linear accelerators were superimposed on the reference images. The anatomy matching software (Varian portal Vision. 6.0) was used, and the displacements in two dimensions and rotation were noted for each treated field to study the patient setup errors. The percentages of mean deviations more than 3 mm in ‘lateral (X) and longitudinal (Y)’ directions were 17.5%, 11.25%, and 7.5% for breast, pelvis, and head and neck cases respectively. In all cases, the percentage of mean deviation with more than 5 mm error was 0.83%. The maximum average mean deviation in all the cases was 1.87. The average mean SD along X and Y directions in all the cases was less than 2.65. The results revealed that the ranges of setup errors are site specific and immobilization methods improve reproducibility. The observed variations were well within the limits. The study confirmed the accuracy and quality of treatments delivered to the patients.

Optimization of dose distribution with multi-leaf collimator using field-in-field technique for parallel opposing tangential beams of breast cancers

3 Dimensional Conformal Radiotherapy (3D-CRT) planning software helps in displaying the 3D dose distribution at different levels in the planned target volume (PTV). Physical or dynamic wedges are commonly applied to obtain homogeneous dose distribution in the PTV. Despite all these planning efforts, there are about 10% increased dose hot spots encountered in final plans. To overcome the effect of formation of hot spots, a manual forward planning method has been used. In this method, two more beams with multi-leaf collimator (MLC) of different weights are added in addition to medial and lateral wedged tangent beams. Fifteen patient treatment plans were taken up to check and compare the validity of using additional MLC fields to achieve better homogeneity in dose distributions. The resultant dose distributions with and without presence of MLC were compared objectively. The dose volume histogram (DVH) of each plan for the PTV was evaluated. The 3D dose distributions and homogeneity index (HI) values were compared. The 3D dose maximum values were reduced by 4% to 7%, and hot spots assumed point size. Optimizations of 3D-CRT plans with MLC fields improved the homogeneity and conformability of dose distribution in the PTV. This paper outlines a method of obtaining optimal 3D dose distribution within the PTV in the 3D-CRT planning of breast cases.

Transverse beam spin asymmetries at backward angles in elastic electron-proton and quasielastic electron-deuteron scattering

We have measured the beam-normal single-spin asymmetries in elastic scattering of transversely polarized electrons from the proton, and performed the first measurement in quasielastic scattering on the deuteron, at backward angles (lab scattering angle of 108°) for Q² = 0.22 GeV²/c² and 0.63 GeV²/c² at beam energies of 362 and 687 MeV, respectively. The asymmetry arises due to the imaginary part of the interference of the two-photon exchange amplitude with that of single-photon exchange. Results for the proton are consistent with a model calculation which includes inelastic intermediate hadronic (πN) states. An estimate of the beam-normal single-spin asymmetry for the scattering from the neutron is made using a quasistatic deuterium approximation, and is also in agreement with theory.

Simple technique for fabrication of shielding blocks for total body irradiation at extended treatment distances

Techniques are being standardized in our department for total body irradiation (TBI) with six MV photons in linear accelerator for preconditioning to bone marrow transplantation (BMT). Individualized shields with low melting point alloy are to be fabricated for shielding critical organs such as lungs, kidneys etc. A method to mount diminished dimension of shields in a tray at 3.75m is designed in the department for a teletreatment distance of four meters with magna field with A simulator image taken with the patient's midplane (MP) at one meter distance is used to mark the dimensions of lung, scaled down by a factor of 3.75/4.0. These lung dimensions are reprinted from the digital simulator image for making the shield. The methodology of the technique using digitized minification in radiography is the first of its kind to be used for shield cutting in magna field radiotherapy.

Strange quark contributions to parity-violating asymmetries in the backward angle G0 electron scattering experiment

We have measured parity-violating asymmetries in elastic electron-proton and quasielastic electron-deuteron scattering at Q2=0.22 and 0.63 GeV2. They are sensitive to strange quark contributions to currents in the nucleon and the nucleon axial-vector current. The results indicate strange quark contributions of approximately < 10% of the charge and magnetic nucleon form factors at these four-momentum transfers. We also present the first measurement of anapole moment effects in the axial-vector current at these four-momentum transfers.

Intramitochondrial crystalline inclusions in nonalcoholic steatohepatitis

Mitochondrial dysfunction is an important element in the pathogenesis of nonalcoholic steatohepatitis (NASH). Intramitochondrial crystals (IMCs) are a well-documented morphological abnormality seen on transmission electron microscopy in this disease. It has been suggested that IMCs consist of phospholipids, but their exact composition remain uncertain many years after their discovery. Micellar phase transitions of phospholipid bilayers is a well-known but little-studied phenomenon in living systems. Its presence in the mitochondria of NASH would offer significant insight into the disease with possible therapeutic implications. We postulated that intramitochondrial disturbances in NASH are sufficient to produce such transitions and that their detection in fresh biopsies would therefore be a dynamic process. To test this, we performed a blinded, prospective analysis of fresh liver biopsy samples immediately fixed under different conditions. Quantitative transmission electron microscopy morphometry, performed by systematically counting total mitochondria and IMCs within areas of uniform dimension, showed a stepwise decline in IMCs with cooler fixation temperature in each subject studied. Randomization testing (Monte Carlo resampling) confirmed that the detection of IMCs was strongly dependent on fixation temperature (P < 0.0001).

CONCLUSION

These results indicate that the intramitochondrial crystals characteristic of NASH are highly dynamic and unstable structures. The findings offer the strongest support yet for their origin in micellar phase transitions. We speculate that such transitions result from microenvironmental changes within the mitochondria and carry therapeutic implications, especially in regard to dietary manipulations of mitochondrial lipid composition.

Formulation and initial experience on patient specific quality assurance for clinical implementation of dynamic IMRT

Intensity modulated radiotherapy (IMRT) is an advanced form of 3D conformal radiotherapy combining several intensity modulated beams to deliver the prescribed dose to the target with precision, sparing the adjacent normal tissue structures. The complex nature of IMRT delivery needs a precise patient specific quality assurance (QA), proper verification of dosimetry and treatment. QA procedures are important measures to ensure that the treatment can be delivered according to the treatment plan. In this report, we are presenting a formulation of a proposed protocol and results of patient specific QA carried on two IMRT plans. The QA consists of an absolute dosimetry, film dosimetry and dynalog files verification of treatment plans. The absolute doses, planar and fluence doses calculated by the TPS are compared with the measured values. The dynalog files recorded during the treatment delivery of two plans were analysed. The measured error in absolute dose is <3% in both the plans. An average of >98% of counts are having <0.1 cm errors in dMLC positions. The average RMS value of leaf motions is <0.05 cm in both the cases. The errors in film dosimetry are <3%. All the results obtained are comparable to the standard values and well within the acceptable limits. The paper outlines the minimum procedures required for the patient specific QA measurements for the clinical implementation of IMRT. The measurements help to understand and confirm the accuracy of IMRT delivery system.

A method for estimation of accuracy of dose delivery with dynamic slit windows in medical linear accelerators

Intensity-modulated radiotherapy (IMRT) clinical dose delivery is based on computer-controlled multileaf movements at different velocities. To test the accuracy of modulation of the beam periodically, quality assurance (QA) methods are necessary. Using a cylindrical phantom, dose delivery was checked at a constant geometry for sweeping fields. Repeated measurements with an in-house designed methodology over a period of 1 year indicate that the method is very sensitive to check the proper functioning of such dose delivery in medical linacs. A cylindrical perspex phantom with facility to accurately position a 0.6-cc (FC 65) ion chamber at constant depth at isocenter, (SA 24 constancy check tool phantom for MU check, Scanditronix Wellhofer) was used. Dosimeter readings were integrated for 4-mm, 10-mm, 20-mm sweeping fields and for 3 angular positions of the gantry periodically. Consistency of standard sweeping field output (10-mm slit width) and the ratios of outputs against other slit widths over a long period were reported. A 10-mm sweeping field output was found reproducible within an accuracy of 0.03% (n = 25) over 1 year. Four-millimeter, 20-mm outputs expressed as ratio with respect to 10-mm sweep output remained within a mean deviation of 0.2% and 0.03% respectively. Outputs at 3 gantry angles remained within 0.5%, showing that the effect of dynamic movements of multileaf collimator (MLC) on the output is minimal for angular positions of gantry. This method of QA is very simple and is recommended in addition to individual patient QA measurements, which reflect the accuracy of dose planning system. In addition to standard output and energy checks of linacs, the above measurements can be complemented so as to check proper functioning of multileaf collimator for dynamic field dose delivery.

Clinical implementation of dynamic intensity-modulated radiotherapy: Dosimetric aspects and initial experience

This paper describes the initial experience of quality assurance (QA) tests performed on the millennium multi-leaf collimator (mMLC) for clinical implementation of intensity-modulated radiotherapy (IMRT) using sliding window technique. The various QA tests verified the mechanical and dosimetric stability of the mMLC of linear accelerator when operated in dynamic mode (dMLC). The mechanical QA tests also verified the positional accuracy and kinetic properties of the dMLC. The stability of dMLC was analyzed qualitatively and quantitatively using radiographic film and Omnipro IMRT software. The output stability, variation in output for different sweeping gap widths, and dosimetric leaf separation were measured. Dose delivery with IMRT was verified against the dose computed by the treatment planning system (TPS). Monitor units (MUs) calculated by the planning system for the IMRT were cross-checked with independent commercial dose management software. Visual inspection and qualitative analysis showed that the leaf positioning accuracy was well within the acceptable limits. Dosimetric QA tests confirmed the dosimetric stability of the mMLC in dynamic mode. The verification of MUs using commercial software confirmed the reliability of the IMRT planning system for dose computation. The dosimetric measurements validated the fractional dose delivery.

The effects of 48 weeks of rosiglitazone on hepatocyte mitochondria in human nonalcoholic steatohepatitis

Rosiglitazone, a thiazolidinedione peroxisome proliferator-activated receptor gamma ligand, reduces disease activity in nonalcoholic steatohepatitis (NASH), a disease associated with hepatocyte mitochondrial crystalline inclusions that are not seen in animal models of NASH. In human and animal studies of adipose tissue, thiazolidinediones may induce mitochondrial biogenesis and associated morphological changes. To determine if rosiglitazone alters the hepatocyte mitochondrial morphology in human NASH, we prospectively and systematically examined liver biopsies from human subjects with NASH before and after 48 weeks of rosiglitazone by transmission electron microscopy. Twenty patients (body mass index = 34 +/- 7) were studied. Four coded sections from each of 20 pretherapy biopsies and each of 20 posttherapy biopsies were examined by transmission electron microscopy. The total hepatocyte mitochondria and crystal-containing mitochondria were counted, and semiquantitative scoring was performed for macrosteatosis, microsteatosis, dilated endoplasmic reticulum, apoptosis, Mallory bodies, and hepatocyte enlargement. The total mitochondria count was unchanged after therapy, but there was a significant increase in crystal-containing mitochondria from 4.0% (95% confidence interval = 1.8-8.8) to 7.2% (95% confidence interval = 3.9-12.6; odds ratio = 1.80; P = 0.04) after the treatment with rosiglitazone. Macrosteatosis (P < 0.001) and Mallory bodies (P = 0.05) significantly decreased, but no change was evident in microsteatosis, cellular enlargement, dilated endoplasmic reticulum, or apoptosis.

CONCLUSION

Rosiglitazone therapy of NASH is associated with increased crystalline inclusions in hepatocyte mitochondria. Whether these are adaptive or pathological remains unknown, and further studies are warranted to assess hepatic mitochondrial function during thiazolidinedione therapy for NASH.

Evaluation methods for detecting changes in beam output and energy in radiation beams from high-energy linear accelerators

There is need for simple methods for checking consistency of beam outputs and energy in linear accelerators used for radiotherapy. A method was designed by the department using perspex phantom with which the dosimetric data of two medical linear accelerators (Clinac 600 CD, Clinac 2300 CD) were evaluated over a period of 30 months. The efficacy of methods followed was checked. Routine beam consistency checks were designed for photon beams with 15 cm/ 5 cm depth ionizations in perspex phantom and variable depth combinations for electron beams. Calculated ionization ratios were compared with measured values to show their significance. The dose/MU for all radiation beams was maintained within 2% accuracy over the period of 30 months. Clinac 600 CD machine showed decreasing trend of cGy/MU, while Clinac 2300 CD showed increasing trend of cGy/MU over a period, which needed tuning of monitor chamber two times each. Tuning of output to achieve standard value was carried out once, for all electron energies when the output dose/MU exceeded 3%. During one week (June 2005), there were slight changes in electron energy detected using the ratio method, which did not recur anytime afterwards. The methods designed are adequate to find the consistency in the beam output and energies in the radiotherapy linacs.

Recessive congenital methaemoglobinaemia: functional characterization of the novel D239G mutation in the NADH-binding lobe of cytochrome b5 reductase

Type I recessive congenital methaemoglobinaemia (RCM), caused by the reduced form of nicotinamide adenine dinucleotide (NADH)-cytochrome b(5) reductase (cytb(5)r) deficiency, manifests clinically as cyanosis without neurological dysfunction. Two mutations, E255- and G291D, have been identified in the NADH-binding lobe of cytb(5)r in previously reported patients, and we have detected a further novel mutation, D239G, in this lobe in two unrelated Irish families. Although one family belongs to the genetically isolated Traveller Community, which separated from the general Irish population during the 1845-48 famine, the D239G mutation was present on the same haplotype in both families. Three known cytb(5)r mutations were also identified, including the R159- mutation, which causes loss of the entire NADH-binding lobe and had previously been reported in an individual with type II RCM. Characterization of the three NADH-binding lobe mutants using a heterologous expression system revealed that all three variants retained stoichiometric levels of flavin adenine dinucleotide with spectroscopic and thermodynamic properties comparable with those of native cytb(5)r. In contrast to the E255- and G291D variants, the novel D239G mutation had no adverse impact on protein thermostability. The D239G mutation perturbed substrate binding, causing both decreased specificity for NADH and increased specificity for NADPH. Thus cytb(5)r deficient patients who are heterozygous for an NADH-binding lobe mutation can exhibit the clinically less severe type I phenotype, even in association with heterozygous deletion of the NADH-binding lobe.

The zonal distribution of megamitochondria with crystalline inclusions in nonalcoholic steatohepatitis

Megamitochondria with crystalline inclusions (MMC) have been previously described in nonalcoholic fatty liver; however, their distribution within hepatic zones is unknown. We sought to determine this distribution from the core liver biopsy specimens of 31 patients: 8 males and 23 females, age range 21 to 72 years. Twenty-nine showed evidence of nonalcoholic steatohepatitis (NASH) on biopsy with steatosis, inflammation, varying degree of fibrosis, ballooned hepatocytes, and Mallory hyaline, and two patients had cryptogenic cirrhosis thought to represent "burned out" NASH. Identified by transmission electron microscopy, the abundance of MMC was compared between low-stage (fibrosis stages 1 and 2) and high-stage (fibrosis stages 3 and 4) groups and between zones with or without difference in fibrosis stage. Regardless of stage, the MMC were distributed equally in all zones and were abundant similarly in low- and high-stage groups. This abundance did not correlate with the degree of oxidative stress (4-hydroxynonenal staining) or with the abundance of ballooned hepatocytes. Consistent with age as a risk factor for more severe disease, the median age for the low-stage group was significantly lower than that of the high-stage group (P =.003). In conclusion, in NASH, the MMC seem to be distributed randomly among zones and without variation in abundance, regardless of the fibrosis stage. The exact function of these structures remains to be defined. In this study, their presence did not seem to correlate with the light microscopic injury pattern represented by ballooned hepatocytes or degree of oxidative stress defined by immunostaining for 4-hydroxynonenal.

Charge symmetry breaking in np-->dpi(0)

The forward-backward asymmetry in np-->dpi(0), which must be zero in the center-of-mass system if charge symmetry is respected, has been measured to be [17.2+/-8.0(stat)+/-5.5(syst)]x10(-4), at an incident neutron energy of 279.5 MeV. This observable is compared to recent chiral effective field theory calculations, with implications regarding the du quark mass difference.

Parity violation in proton-proton scattering at 221 MeV

The parity-violating longitudinal analyzing power, A(z), has been measured in pvectorp elastic scattering at an incident proton energy of 221 MeV. The result obtained is A(z) = [0.84+/-0.29(stat)+/-0.17(syst)]x10(-7). This experiment is unique in that it selects a single parity violating transition amplitude (3P2 - 1D2) and consequently directly constrains the weak meson-nucleon coupling constant h(pp)(rho). When this result is taken together with the existing pvectorp parity violation data, the weak meson-nucleon coupling constants h(pp)(rho) and h(pp)(omega) can, for the first time, both be determined.

Wet gangrene in hemodialysis patients with calciphylaxisis is associated with a poor prognosis

Calciphylaxis is a rare syndrome characterized by progressive vascular calcification and ischemic tissue loss in patients with chronic renal failure. We report our five-year experience with five patients who developed foot gangrene due to calciphylaxis. All five patients had characteristic clinical, laboratory, and radiologic findings of the disorder, but no diagnostic variable was uniformly present. All five had progressed to advanced gangrene at the time of surgical consultation. Despite aggressive local attempts to control infection, all five patients died of septic complications. Parathyroidectomy was performed in three patients but did not alter the course in any case. This small experience suggests that the outcome of foot gangrene associated with calciphylaxis is predicated on the degree of tissue loss. Aggressive local wound care does not appear to be adequate to control infection in patients who have already developed gangrene. Although parathyroidectomy may have important long-term advantages in patients with calciphylaxis, it does not appear to affect outcome in these advanced cases.

A coding region determinant of instability regulates levels of manganese superoxide dismutase mRNA

The mitochondria-localized manganese superoxide dismutase (MnSOD), serves a key cytoprotective role against reactive oxygen species arising from a variety of cellular processes and immunological stresses. Previous data from our laboratory suggest that the regulation of the rat MnSOD gene may occur not only at the transcriptional but quite possibly at the post-transcriptional level. To verify this hypothesis, we have attempted to identify regions within the rat MnSOD cDNA that may be functionally involved in regulating the stability of the mRNA. Using a c-fos-based promoter activation system, we have identified an approximately 280-nucleotide fragment within the MnSOD mRNA coding region that, when fused to a rabbit beta-globin gene, destabilizes the normally stable beta-globin mRNA. This cis-directed destabilization phenomenon confers its effects independent of position and stimulus. Most importantly, the MnSOD coding region determinant functions when placed in the 3'-untranslated region of the beta-globin transcript, demonstrating its activity in the absence of ribosome transit. We feel that these data provide a mechanistic basis for both the basal and stimulus-dependent post-transcriptional regulation of MnSOD.

Production of (4)(double Lambda)H hypernuclei

An experiment demonstrating the production of double-Lambda hypernuclei in (K(-),K(+)) reactions on (9)Be was carried out at the D6 line in the BNL alternating-gradient synchrotron. The technique was the observation of pions produced in sequential mesonic weak decay, each pion associated with one unit of strangeness change. The results indicate the production of a significant number of the double hypernucleus (4)(double Lambda)H and the twin hypernuclei (4)(Lambda)H and (3)(Lambda)H. The relevant decay chains are discussed and a simple model of the production mechanism is presented. An implication of this experiment is that the existence of an S = -2 dibaryon more than a few MeV below the double Lambda mass is unlikely.

Multiloculated peritoneal inclusion cysts with splenic involvement: a case report

Multilocular peritoneal inclusion cysts (MPICs) are most commonly found in women of reproductive years and involve the abdomen, pelvis, and retroperitoneum. It is commonly thought that these cysts are due to an inflammatory reaction. Patients usually present with chronic abdominal or pelvic pain and are diagnosed by ultrasound or CT scan. Although there are experimental medical treatment options surgical excision remains the current recommended primary therapy for symptomatic disease. The following case describes a pregnant female with rare MPIC involving the spleen and peritoneum. Biological behavior of MPIC and current therapy options are also discussed.

Test of intron predictions reveals novel splice sites, alternatively spliced mRNAs and new introns in meiotically regulated genes of yeast

Correct identification of all introns is necessary to discern the protein-coding potential of a eukaryotic genome. The existence of most of the spliceosomal introns predicted in the genome of Saccharomyces cerevisiae remains unsupported by molecular evidence. We tested the intron predictions for 87 introns predicted to be present in non-ribosomal protein genes, more than a third of all known or suspected introns in the yeast genome. Evidence supporting 61 of these predictions was obtained, 20 predicted intron sequences were not spliced and six predictions identified an intron-containing region but failed to specify the correct splice sites, yielding a successful prediction rate of <80%. Alternative splicing has not been previously described for this organism, and we identified two genes (YKL186C/ MTR2 and YML034W) which encode alternatively spliced mRNAs; YKL186C/ MTR2 produces at least five different spliced mRNAs. One gene (YGR225W/ SPO70 ) has an intron whose removal is activated during meiosis under control of the MER1 gene. We found eight new introns, suggesting that numerous introns still remain to be discovered. The results show that correct prediction of introns remains a significant barrier to understanding the structure, function and coding capacity of eukaryotic genomes, even in a supposedly simple system like yeast.

Effective use of percutaneous cholecystostomy in high-risk surgical patients: techniques, tube management, and results

HYPOTHESIS

Percutaneous cholecystostomy (PC) is an effective, safe treatment in patients with suspected acute cholecystitis and severe concomitant comorbidity.

DESIGN

Retrospective medical record review from March 1989 to March 1998.

SETTING

Referral community teaching hospital (450 beds) in rural Wisconsin.

PATIENTS

Twenty-two consecutive patients underwent PC tube placement over a 10-year period. Twenty procedures were for acute cholecystitis (14 calculous, 6 acalculous) and 2 were for diagnostic dilemmas. Nineteen (86%) of 22 patients were American Society of Anesthesiologists class 4; 3 (14%) were class 3.

INTERVENTIONS

Pigtail catheters (8F-10F) placed by means of ultrasound or computed tomographic localization, with or without fluoroscopic adjunct.

MAIN OUTCOME MEASURES

Thirty-day mortality, complications, clinical improvement as determined by fever and pain resolution, normalization of leukocytosis, further biliary procedures required, and outcome after drain removal.

RESULTS

Twenty-two patients underwent PC for presumed acute cholecystitis based on ultrasound and clinical findings. All patients received antibiotics prior to PC for 24 or more hours. Thirty-day mortality was 36% (8 patients), reflecting severity of concomitant disease. Minor complications occurred in 3 of 22 patients. Clinical improvement occurred in 18 (82%) of 22 patients-15 (68%) within 48 hours. Follow-up of fourteen 30-day survivors is as follows: 7 (50%) had drains removed because the gallbladder was stone free, 4 (29%) had drains remaining due to persistent stones, 2 (14%) underwent cholecystectomy, and 1 (7%) awaits scheduled surgery. Only 1 (12.5%) of 8 patients developed biliary complications after drain removal, requiring endoscopic retrograde cholangiopancreatography 9 months after drain removal. One patient required urgent cholecystectomy after failure to respond to PC. This patient died of a perioperative myocardial infarction.

CONCLUSIONS

Percutaneous cholecystostomy is an effective, safe treatment in patients with suspected acute cholecystitis and severe concomitant comorbidity. Laparoscopic cholecystectomy is recommended as definitive treatment for patients whose risk for general anesthesia improves in follow-up. Drains can be safely removed once all gallstones are cleared. In patients with severe concomitant disease, drains can be left with a low incidence of complications if stones remain.

Changes in thyroid gland morphology after acute acrylamide exposure

High exposure to the acrylamide monomer has been associated with neuropathy and neurotoxic effects. Chronic lower exposure causes endocrine disruption associated with thyroid, testicular, and mammary tumors. To investigate mechanisms of endocrine disruption, short-term, low-level oral dosing studies were conducted. Weanling female Fischer 344 rats were acclimatized for two weeks before dosing. Controls were given distilled water by gavage and rats in other groups were given acrylamide at doses of 2 mg/kg/day and 15 mg/kg/day for 2 or 7 days by gavage. Twenty-four h after the last dose, the rats were killed by decapitation. Trunk blood was collected for hormone analyses and tissues for histopathological examination. There were no toxicity-related deaths, no clinical signs of toxicity, and no significant difference in the mean body weight of animal groups. Histopathological examination of select tissues showed no lesions of pathologic significance. Plasma thyroxine (T4), thyroid stimulating hormone (TSH), prolactin (PRL), and pituitary TSH and PRL analyses did not reveal significant changes between control vs. treated rats. In the 7-day study, however, there was a slight dose-dependent increase in plasma T4 and a slight dose-dependent decrease in plasma TSH. Thyroid gland morphometry showed a significant (p < 0.05) decrease in the colloid area and a significant increase (p < 0.05) in the follicular cell height of treated rats as compared to controls. The follicular area shrinkage was similar in both studies. These results show a very early endocrine response to very low levels of toxic insult and opens other venues to further investigate the mechanisms of endocrine disruption by acrylamide.

Shotgun wound management: a comparison of slug and pellet injuries

Shotgun slug injuries have received little attention while shotgun pellet wounds have been well described. Twenty-two shotgun pellet and 13 shotgun slug injuries treated over a 14-year period were retrospectively reviewed. Extremity and thoracic wounds were most frequent in both groups. The incidence of vascular and nerve injuries was similar for slug and pellet wounds. Angiography was more often used to evaluate pellet wounds for vascular disruption. The rate of wound infection was 38% for slug wounds versus 32% for pellet injuries. Tissue grafting was more frequently necessary for reconstruction after pellet injury. Long-term disability was documented in 15% of patients with pellet wounds and 23% with slug wounds. Despite similarities in wound location and outcomes, the ballistic differences between shotgun slugs and pellets resulted in significant differences in wounding characteristics and extent of injury which have important ramifications in management.

Reconstruction of the scapholunate ligament in a cadaver model using a bone-ligament-bone autograft from the foot

This study is an investigation of a new procedure in which the scapholunate interosseous ligament (SLIL) is reconstructed using a bone-ligament-bone autograft from the foot. After investigation, the dorsal medial portion of the navicular-first cuneiform ligament (NFCL) was chosen for testing as a potential donor since it is similar in length and thickness to the SLIL and it is easily harvested with minimal potential donor site morbidity. Eight SLILs and NFCLs were harvested from fresh-frozen cadavers. Biomechanical extensometry testing was performed using an Instron 1000 machine. A 5-mm-wide central portion of the NFCL was tested since this width was compatible with the technical aspects of reconstructing the SLIL. Both ligaments were tested for elastic properties, including stiffness, load to failure, and deformation to failure. Mean length of the NFCL was 7.6 mm (range, 5.5-8.5 mm). Stiffness of the NFCL was 10.6 x 10(5) Nm (range, 8.0-13.0 Nm) compared with 14.4 x 10(5) Nm for the SLIL (range, 10.0-19.5 Nm). Peak load to failure for the NFCL was 1,980 N (range, 1,530-2,940 N) compared with 2,940 N for the SLIL (range, 1,780-4,050 N). Total elongation to failure for the NFCL was 2.50 mm (range, 1.7-3.2 mm) compared with 3.2 mm for the SLIL (range, 2.1-5.2 mm). Thus, the biomechanical characteristics of the NFCL were found to be very similar to those of the SLIL. Having established the biomechanical similarities of the 2 ligaments, we are currently using the NFCL to reconstruct the sectioned SLIL in a fresh-frozen cadaver model. Early results suggest that this procedure is feasible for restoration of normal kinematics of the wrist.

Comparison of crossed pins and external fixation for correction of angular deformities about the knee in children

External fixation was compared to crossed Steinman pins and plaster for fixation after osteotomy about the knee in children. A group of 26 patients treated by external fixation was compared to a control group of 26 patients fixed with crossed Steinman pins and casting. The groups were matched for age, height, and weight. Overall there was a 100% union rate. Preoperative deformity and postoperative correction were similar in the two groups. The time to union was significantly longer, and there were significantly more complications in the external fixator group. There were 16 complications (62%) in the external fixator group and five (19%) in the control group. Complications included pin tract infections, peroneal nerve palsy, and delayed union. External fixation provides certain advantages for fixation after osteotomies about the knee in children but is associated with a variety of complications.

Coronary vascular responsiveness to adenosine is impaired additively by blockade of nitric oxide synthesis and a sulfonylurea

OBJECTIVES

We sought to define effects of glibenclamide, a sulfonylurea known to block ATP-dependent potassium (KATP) channels, and Nomega-nitro-L-arginine methyl ester (L-NAME), an L-arginine analog known to block nitric oxide (NO) synthesis, on coronary vascular responsiveness to adenosine.

BACKGROUND

The role of adenosine in coronary flow regulation becomes increasingly important when KATP channel function or NO synthesis is impaired. Both variables are potentially altered in patients with coronary artery disease taking a sulfonylurea.

METHODS

Dose-response curves relating coronary conductance to plasma adenosine concentration were obtained by using intracoronary infusions of adenosine (10 to 1,000 microg/min) in chronically instrumented dogs.

RESULTS

ED50, the plasma concentration of adenosine needed to produce 50% of the maximal increase in conductance under baseline conditions, increased threefold after either 1 or 10 mg/kg of L-NAME. ED50 also increased in response to glibenclamide in a dose-related fashion (5.7-fold increase per 1 mg/kg body weight of glibenclamide). Effects of combined blockade of KATP channels and NO synthesis were additive, with increases in ED50 as high as 15-fold. Both L-NAME and glibenclamide increased systemic pressure and reduced coronary conductance, confirming the roles of NO and KATP channels in regulating coronary and systemic vascular tone under rest conditions as well as during stress.

CONCLUSIONS

Coronary vascular responsiveness to adenosine is blunted in vivo by both L-NAME and glibenclamide. Effects of the sulfonylurea and blockade of NO synthesis are additive and can limit coronary vasodilation as well as other responses involving KATP channels and NO.

Pharmacokinetic and phase I trial of intraperitoneal carboplatin and cyclosporine in refractory ovarian cancer patients

PURPOSE

The feasibility and pharmacokinetics of cyclosporine (CsA) delivered intraperitoneally (IP) have not been previously explored. We performed a pharmacokinetic study of IP CsA followed by a phase I dose-escalation trial of the combination of IP CsA and carboplatin in refractory ovarian cancer patients.

PATIENTS AND METHODS

A pilot study was performed of three patients who received 1, 10, and 20 mg/kg IP CsA alone. Subsequently, a phase I trial of 35 patients was performed between April 1990 and April 1993. Whole-blood and IP fluid CsA concentrations were measured at serial time points. The highest dose delivered IP was 34.6 mg CsA/kg in combination with carboplatin (250 mg/m2 or 300 mg/m2, depending on creatinine clearance), which was not dose-escalated. The area under the concentration-time curve (AUC) for CsA and half-life (T1/2) were calculated. Objective and serologic responses were noted, and toxicity was graded using the National Cancer Institute common toxicity criteria.

RESULTS

The feasibility of delivering IP CsA alone was established. We observed a 1,000:1 ratio between IP fluid and blood concentrations at 20 mg CsA/kg. Pharmacokinetic analysis confirmed that at 20 mg CsA/kg, there was an IP fluid-to-blood AUC ratio of 600:1 in favor of peritoneal exposure. At the highest dose delivered, 34.6 mg CsA/kg, the mean IP CsA levels of 1,110 micrograms/ mL were tolerated moderately well and the IP fluid-to-blood ratio of 1,000:1 was maintained. Blood and IP CsA concentrations were analyzed in the presence and absence of IP carboplatin. At 20 mg CsA/kg, there was no difference in either mean blood CsA levels (0.9 microgram/ mL) or mean IP CsA concentrations (1,000 micrograms/mL) obtained in the absence or presence of carboplatin. The most common toxicity in the phase I study was anemia, seen in 66% of patients. Common toxicities at the maximum CsA dose delivered (34.6 mg/kg) were anemia, leukopenia, thrombocytopenia, and hypertension. In this trial, three objective responses (two complete and one partial) were observed for a duration of 3 to 11 months. Control of platinum-resistant ascites was an important feature, noted in five of eight patients.

CONCLUSION

We have established the feasibility of delivering IP CsA up to doses of 34.6 mg/kg in conjunction with carboplatin, and the sustaining of IP fluid to blood ratios of 1,000:1. The IP administration of CsA resulted in a favorable ratio of exposure for the peritoneal cavity compared with systemic exposure, indicating a therapeutic advantage of this approach with a significant decrease in systemic toxicity. We recommend that 34.6 mg/ kg of IP CsA be tested as a phase II dose in combination with carboplatin in refractory ovarian cancer patients. This report provides the groundwork for future studies using IP CsA, both as a chemomodulator of platinum and of multidrug resistance.

Generation of cDNA expression libraries enriched for in-frame sequences

Bacterial cDNA expression libraries are made to reproduce protein sequences present in the mRNA source tissue. However, there is no control over which frame of the cDNA is translated, because translation of the cDNA must be initiated on vector sequence. In a library of nondirectionally cloned cDNAs, only some 8% of the protein sequences produced are expected to be correct. Directional cloning can increase this by a factor of two, but it does not solve the frame problem. We have therefore developed and tested a library construction methodology using a novel vector, pKE-1, with which translation in the correct reading frame confers kanamycin resistance on the host. Following kanamycin selection, the cDNA libraries contained 60-80% open, in-frame clones. These, compared with unselected libraries, showed a 10-fold increase in the number of matches between the cDNA-encoded proteins made by the bacteria and database protein sequences. cDNA sequencing programs will benefit from the enrichment for correct coding sequences, and screening methods requiring protein expression will benefit from the enrichment for authentic translation products.

Blockade of nitric oxide synthesis reduces myocardial oxygen consumption in vivo

BACKGROUND

Although cardiac myocytes and coronary vascular endothelium are known to express a constitutive form of NO synthase, the in vivo effects of tonic endogenous production of NO on myocardial O2 consumption and contractile performance remain unclear.

METHODS AND RESULTS

The effects of blockade of NO synthase were determined in intact dogs. Myocardial O2 consumption decreased systematically over a wide range of hemodynamic demand after the systemic administration of N omega-nitro-L-arginine methyl ester (L-NAME) or N omega-nitro-L-arginine. Decreases after doses of 1 and 10 mg/kg L-NAME averaged 23 +/- 3.8% and 34 +/- 7.2% at a heart rate of 90 bpm in open-chest animals. Similar reductions occurred after the administration of L-NAME and N omega-nitro-L-arginine in chronically instrumented animals and were unaffected by beta-adrenergic blockade. Intracoronary infusion of L-NAME in chronically instrumented animals reduced both myocardial O2 consumption and regional segment shortening, even at a dose that did not increase systemic arterial pressure.

CONCLUSIONS

The blockade of NO synthesis reduces myocardial O2 consumption in vivo. The decrease in O2 consumption is accompanied by a decrease in segment shortening. It involves a direct myocardial action of NO, is unaffected by beta-blockade, and is consistent with in vitro studies indicating that low levels of NO augment contractile performance by inhibition of a cGMP-dependent phosphodiesterase.

Serial cytological assay of micronucleus induction: a new tool to predict human cancer radiosensitivity

BACKGROUND AND PURPOSE

The micronucleus test, generally done in cultured tumour cells irradiated in vitro, has not gained wide acceptance in predicting human cancer radiosensitivity. The purpose of this study was to see if micronucleus assay by serial scrape smear cytology can predict oral cancer radiosensitivity.

MATERIALS AND METHODS

Forty nine oral cancer patients given radiotherapy (60 Gy/25 fractions/5 weeks) form the study population. Serial scrape smears were taken from their tumours before treatment and after delivery of 2, 5, 8 and 12 fractions, stained by Giemsa and the number of micronucleated cells (MNC) noted. The patients were grouped to those who developed tumour recurrence ('Resistant') and those who did not ('Sensitive'), and the pattern of micronucleus induction compared.

RESULTS

Both groups of tumours had MNC even before treatment, with statistically significant dose-related increase with radiotherapy. The sensitive group had a higher mean increase in MNC count than the resistant group (6.1 times and 3.6 times the pre-treatment value, respectively) and better correlation with dose (r = 0.54 vs. 0.43). The increase in MNC count occurred earlier in the resistant group than in the sensitive, the TMNC (time for the pre-treatment value to double) being 3.3 days and 7.6 days, respectively. Also, the resistant group showed a plateauing of the MNC count which the sensitive group lacked.

CONCLUSIONS

The higher MNC induction in the sensitive tumours suggests the usefulness of the assay as a test of radiosensitivity. The differing patterns of MNC increase suggest that differences in proliferation rate is an important cause of tumour failure. Serial cytological assay of micronucleus induction can identify both radiosensitivity and proliferation characteristics of tumours, and thus may turn out to be a useful test of radiocurability.

Modulation of platinum sensitivity and resistance by cyclosporin A in refractory ovarian and fallopian tube cancer patients: a phase II study

Our objective was to assess the activity of cyclosporin A (CsA) used as a chemomodulator of carboplatin in refractory ovarian and fallopian tube cancer patients. Fifty-one patients (47 epithelial ovarian, 1 ovarian mixed mesodermal tumor, and 3 fallopian tube carcinomas) were enrolled in a prospective Phase II trial of CsA and carboplatin. CsA was infused as a loading dose of 10 mg/kg over 5 h, followed by carboplatin infused over 30 min at an AUC of 6 mg/ml x min, then a 24-h continuous infusion of 11.6 mg/kg CsA. The patients received this protocol as second- to sixth-line therapy and had received between 1 and 3 prior platinum-based regimens. Eight patients received more than six cycles every 28 days, 34 patients received three to six cycles; and 9 patients received only one or two cycles. Thirty-eight patients were evaluable for objective response, and in an additional nine patients, CA-125 was the only marker of response. Four patients had no marker of disease. Of evaluable patients, 74% were platinum resistant. There were nine objective responses (one complete and eight partial responses) for an overall response rate in evaluable patients of 24%, with a median duration of response of 7 months (range, 3-38+ months). No responses were seen in patients who had received only one or two cycles of therapy. Among the strictly defined platinum-resistant patients, there was an overall 14% response rate, including one partial response seen after five prior regimens of chemotherapy including paclitaxel, and one ongoing complete response for 38+ months. Among the rest of the patients (those who were potentially platinum sensitive), there was an overall 50+ response rate; four of five responses were seen in patients with a platinum-free interval of <24 months, with only one response seen in a patient with a platinum-free interval of >24 months. Of evaluable patients, 34% had stable disease for a duration of 3-19 months. The most common grade 3 or 4 toxicity, thrombocytopenia, was seen in 22% of the patients. Hypertension, which responded to medications, was seen in 18% of the patients during the CsA infusion. We concluded that this CsA/carboplatin regimen is active in potentially platinum-sensitive patients and compares well with the expected response rate of 30% in patients with a platinum-free interval <24 months who are retreated with platinum. Moreover, this regimen had modest but real activity in platinum-resistant patients.

Phase I trial of intravenous carboplatin and cyclosporin A in refractory gynecologic cancer patients

Our objective was to determine the maximum tolerated dose of cyclosporin A (CsA) delivered as a loading dose (LD) and continuous i.v. infusion (CI) in combination with carboplatin in patients with refractory gynecologic cancers. Twenty-nine heavily pretreated patients (25 ovarian epithelial, 2 cervical, and 2 endometrial carcinomas) received 113 cycles of CsA and carboplatin from September 1989 to September 1991. Twenty-four of these 29 carcinomas were strictly defined to be platinum resistant. CsA was administered as a LD escalated from 6 to 10 mg/kg followed by a 24-h CI from 2.5 to 14.5 mg/kg/day. Carboplatin was targeted to an area under the time versus concentration curve (AUC) of 6 mg/ml x min and was not dose escalated. Whole-blood CsA concentrations (fluorescence polarization immunoassay) at the maximum tolerated dose (10 mg/kg LD, 14.5 mg/kg/day CI) ranged from 2.4 to 3.0 microgram/ml over 12 h. Estimated median carboplatin AUC, based on calculated carboplatin clearance, was 7.9 mg/ml x min. The dose-limiting toxicity of the combination of CsA and carboplatin was grade 4 thrombocytopenia. Grade 3 or 4 thrombocytopenia occurred in 35% of the patients, which could be explained by the effects of carboplatin (AUC of 6 mg/ml x min) alone. Overall, neutropenia occurred in 24% of the patients and anemia in 17% of the patients. Grade 3 or 4 nausea or vomiting was noted in 10 and 14% of the patients, respectively. Grade 3 hypertension during CsA administration occurred in 14% of the patients. No grade 3 or 4 nephrotoxicity was seen in this trial. Three objective responses were noted: one complete response (11 months) and one partial response (5 months), both in potentially platinum-sensitive patients with platinum-free intervals of only 9 months each. One platinum-resistant patient had a partial response for 21 months. Five additional patients experienced >75% reduction of CA-125 or a return to a normal CA-125 titer. We concluded that whole-blood CsA concentrations of >3.0 microgram/ml (as seen when CsA is used as a modulator of multidrug resistance) were not achievable in this combination with carboplatin in this population of heavily pretreated gynecologic cancer patients. However, because CsA is used in this trial as a chemosensitizer in platinum-sensitive tumors and as a chemomodulator of platinum resistance, we targeted a CsA concentration of >1.0 microgram/ml, which was achieved. The CsA dose recommended for a Phase II trial of this combination is 10 mg/kg LD and 11.6 mg/kg/day CI, which results in blood CsA concentrations ranging from 1.2 to 1.3 microgram/ml over 12 h. Responses in this population of refractory gynecologic cancer patients are unusual, and these encouraging results form the basis for a Phase II trial of this combination.

Subcutaneous transposition of the ulnar nerve for treatment of cubital tunnel syndrome

Subcutaneous transposition of the ulnar nerve has been widely reported as a successful surgical treatment for ulnar neuropathy at the elbow attributable to a variety of causes. Accepted indications for anterior transposition include any anatomic lesion that interferes with or impinges on the nerve along its native course. This may include a tumor, ganglion, osteophyte, valgus deformity or instability, or subluxation of the nerve, as listed previously. The surgical technique of ASCT also was described thoroughly earlier in this article. Points that warrant emphasis include thorough decompression along the entire course of the nerve, an attempt to preserve the venous plexus that accompanies the nerve, identification and preservation of branches of the medial antebrachial cutaneous nerve, and resection of a 3 to 6 cm segment of the medial intramuscular septum. Poor prognostic indicators include age over 50 years; relatively advanced neuropathy, as noted by electrical evidence of demyelination; or aggravating medical conditions, such as diabetes or alcoholism. Complications include neuroma of the medial antebrachial cutaneous nerve and resubluxation posterior to the medial epicondyle. In cases of reoperation for recurrent or persistent symptoms, inadequate release, most commonly at the medial intramuscular septum, was sited as the cause of failure in over 90% of cases. In a few cases, compression was found at the site of a fasciodermal sling. The majority of complications therefore were technical in nature and probably could have been avoided by strict attention to basic principles. Controversy surrounds the appropriate treatment for approximately half of patients in whom no clearly definable cause can be found. These cases are either attributed to "repetitive strain" or lumped into the "idiopathic" category. The pathophysiology leading to neuropathy in these groups is poorly understood, so the rationale for choosing one surgical procedure over another remains somewhat obscure. In the absence of an anatomic lesion, proponents of in situ decompression believe transposition involves unnecessary dissection, with attendant risks of devasularization or injury to the nerve or surrounding structures. Advocates of ASCT point out that the nerve may be compressed at any of several points along its course, as outlined in Fig. 1. Unlike in situ decompression, therefore, a properly performed anterior transposition assures adequate decompression at all points along its course. Indications for subcutaneous versus submuscular transposition are even less clear. Some believe submuscular transposition should be performed for more severe neuropathy, when muscular atrophy is present. Other authors point out that thin patients will be susceptible to repeated minor trauma if the nerve is left in a subcutaneous position. Neither of these contentions is supported consistently by available published data. In most cases of failed subcutaneous transposition, submuscular transposition has been used as a salvage procedure simply to place the nerve in an unscarred bed. Answers to the unresolved issues await well-designed studies. Nevertheless, there is ample cause for optimism given that adherence to basic principles has resulted in satisfactory results for 85% to 95% of patients regardless of the procedure chosen.

Synthesis and quantitative structure-activity relationship of a novel series of small conductance Ca(2+)-activated K+ channel blockers related to dequalinium

The synthesis, pharmacological testing, and quantitative structure-activity relationship studies of a novel series of bisquinolinium small conductance Ca(2+)-activated K+ channel blockers (23) related to dequalinium are described. In this series, two quinolinium rings are linked via the 4-position to an alpha, omega-diamino alkylene chain and the ring N atom is quaternized with a methyl or benzyl group. The exocyclic N atom can be replaced by O, S, or CH2 but with some loss of potency. The quinoline groups do not have to be quaternized for blocking activity, as long as they are basic enough to be protonated at the site of action. For the quaternary compounds, there is considerable steric tolerance for the group R attached to the ring N atom of the quinoline; a benzyl group gave the optimum potency in this series. Moreover, and in contrast to previously reported results for dequalinium analogues, there is no correlation of activity to previously reported results for dequalinium analogues, there is no correlation of activity with N1 charge or EHOMO. On the other hand, a good correlation was obtained between the blocking potency of the compounds and ELUMO [pEMR = 1.16(+/-0.26)ELUMO + 5.33(+/-01.29)(n = 11, r= 0.83, s = 0.243)]. It has been possible to combine this equation with the previously reported ELUMO correlation for a series of dequalinium analogues to include all the compounds of both series [pEMR = 1.17(+/-0.15)ELUMO +5.33(+/-0.76)(n =24, r = 0.85, s = 0.249)]. A possible physical meaning for the ELUMO correlation based upon the principle of maximum hardness is discussed.

Variant and invariant high-probability requests: increasing appropriate behaviors in children with emotional-behavioral disorders

This study examined the effects of variant versus invariant high-probability (high-p) request sequences on the performance of requests to initiate a social bid by young children with emotional-behavioral disorders. In the initial phases of the investigation, a multiple baseline design showed that the delivery of invariant sequences (i.e., high-p requests delivered in the same sequence) produced initial increases in compliance to requests to initiate a social bid to a peer. However, increases were not maintained across the invariant condition. The delivery of variant high-p sequences produced increases in compliance to requests to initiate social bids that were maintained across the variant condition. In a follow-up condition, the number of requests within the pool of the variant and invariant high-p requests were controlled. Results of the follow-up condition replicated those found in the initial condition. Implications for applied use and future research are discussed.