Utilization of Locum Tenens in Neurosurgery

INTRODUCTION

Despite its rising popularity, little has been described about locum tenens employment (locums) in neurosurgery. This study provides the first nationwide overview of the locums neurosurgery experience.

METHODS

An anonymous online survey examined practice characteristics of respondents, extent of and satisfaction with locums, motivations for pursuing locums, case volumes, agencies used, compensation, and positive/negative aspects of experiences. Responses were collected between November 2020 and February 2021.

RESULTS

Response rate for the 1852 neurosurgeons who opened the survey request was 4.9%; 36 of 91 respondents had previously worked locums and were commonly motivated by compensation or transitioning to new jobs or retirement. In our response group, 92% of locums respondents had taken more than one position and 47% had taken more than 10. Neurosurgeons performing <200 cases/year were significantly more likely to have also worked locums than those performing >200 cases/year (41.6% locums, 12.7% non-locums, P = 0.001). Responses showed that 69% of locums respondents earned $2000-$2999/day and 16% earned >$3500/day. Nearly 78% of locums respondents were satisfied with their experience(s) and 86% would take another future locums position. Being in practice for >15 years was significantly associated with satisfaction with locums (P = 0.03). Reported flaws included unfamiliarity with hospitals, limited continuity of care, credentialing burdens, and inadequate travel compensation.

CONCLUSIONS

Locums is utilized by neurosurgeons across multiple practice types and may serve to complement workloads or "fill in gaps" between longer-term employment. Overall, locums neurosurgeons are well compensated, and the majority are satisfied with their experience(s). Inevitably, flaws still exist with locums employment, which may be the focus of organized efforts aiming to improve the experience.

Mapping Spinal Cord Stimulation-Evoked Muscle Responses in Patients With Chronic Spinal Cord Injury

OBJECTIVES

Epidural spinal cord stimulation (eSCS) has shown promise for restoring some volitional motor control after spinal cord injury (SCI). Maximizing therapeutic response requires effective spatial stimulation generated through careful configuration of anodes and cathodes on the eSCS lead. By exploring the way the spatial distribution of low frequency stimulation affects muscle activation patterns, we investigated the spatial specificity of stimulation-evoked responses for targeted muscle groups for restoration after chronic SCI (cSCI) in participants in the Epidural Stimulation After Neurologic Damage (E-STAND) trial.

MATERIALS AND METHODS

Fifteen participants with Abbreviated Injury Scale A cSCI from the E-STAND study were evaluated with a wide range of bipolar spatial patterns. Surface electromyography captured stimulation-evoked responses from the rectus abdominis (RA), intercostal, paraspinal, iliopsoas, rectus femoris (RF), tibialis anterior (TA), extensor hallucis longus (EHL), and gastrocnemius muscle groups bilaterally. Peak-to-peak amplitudes were analyzed for each pulse across muscles. Stimulation patterns with dipoles parallel (vertical configurations), perpendicular (horizontal configurations), and oblique (diagonal configurations) relative to the rostral-caudal axis were evaluated.

RESULTS

Cathodic stimulation in the transverse plane indicated ipsilaterally biased activation in RA, intercostal, paraspinal, iliopsoas, RF, TA, EHL, and gastrocnemius muscles (p < 0.05). We found that caudal cathodic stimulation was significantly more activating only in the RF and EHL muscle groups than in the rostral (p < 0.037 and p < 0.006, respectively). Oblique stimulation was found to be more activating in the RA, intercostal, paraspinal, iliopsoas, and TA muscle groups than in the transverse (p < 0.05).

CONCLUSIONS

Cathodic stimulation provides uniform specificity for targeting laterality. Few muscle groups responded specifically to variation in rostral/caudal stimulation, and oblique stimulation improved stimulation responses when compared with horizontal configurations. These relations may enable tailored targeting of muscle groups, but the surprising amount of variation observed suggests that monitoring these evoked muscle responses will play a key role in this tailoring process.

CLINICAL TRIAL REGISTRATION

The Clinicaltrials.gov registration number for the study is NCT03026816.

Effect of epidural spinal cord stimulation on female sexual function after spinal cord injury

Sexual dysfunction is a common consequence for women with spinal cord injury (SCI); however, current treatments are ineffective, especially in the under-prioritized population of women with SCI. This case-series, a secondary analysis of the Epidural Stimulation After Neurologic Damage (E-STAND) clinical trial aimed to investigate the effect of epidural spinal cord stimulation (ESCS) on sexual function and distress in women with SCI. Three females, with chronic, thoracic, sensorimotor complete SCI received daily (24 h/day) tonic ESCS for 13 months. Questionnaires, including the Female Sexual Function Index (FSFI) and Female Sexual Distress Scale (FSDS) were collected monthly. There was a 3.2-point (13.2%) mean increase in total FSFI from baseline (24.5 ± 4.1) to post-intervention (27.8 ± 6.6), with a 4.8-50% improvement in the sub-domains of desire, arousal, orgasm and satisfaction. Sexual distress was reduced by 55%, with a mean decrease of 12 points (55.4%) from baseline (21.7 ± 17.2) to post-intervention (9.7 ± 10.8). There was a clinically meaningful change of 14 points in the International Standards for Neurological Classification of Spinal Cord Injury total sensory score from baseline (102 ± 10.5) to post-intervention (116 ± 17.4), without aggravating dyspareunia. ESCS is a promising treatment for sexual dysfunction and distress in women with severe SCI. Developing therapeutic interventions for sexual function is one of the most meaningful recovery targets for people with SCI. Additional large-scale investigations are needed to understand the long-term safety and feasibility of ESCS as a viable therapy for sexual dysfunction. Clinical Trial Registration:https://clinicaltrials.gov/ct2/show/NCT03026816, NCT03026816.

Neuromodulation Through Spinal Cord Stimulation Restores Ability to Voluntarily Cycle After Motor Complete Paraplegia

Abstract Epidural spinal cord stimulation (eSCS) of the lower thoracic spinal cord has been shown to partially restore volitional movement in patients with complete chronic spinal cord injury (cSCI). Combining eSCS with intensive locomotor training improves motor function, including standing and stepping, but many patients with cSCI suffer from long-standing muscle atrophy and loss of bone mineral density, which may prohibit safe implementation. Safe, accessible, and effective avenues for pairing neuromodulation with activity-based therapy remain unexplored. Cycling is one such option that can be utilized as an eSCS therapy given its low-risk and low-weight-bearing requirement. We investigated the feasibility and kinematics of motor-assisted and passive cycle-based therapy for cSCI patients with epidural spinal cord stimulation. Seven participants who underwent spinal cord stimulation surgery in the Epidural Stimulation After Neurologic Damage (E-STAND) trial (NCT03026816) participated in a cycling task using the motor assist MOTOmed Muvi 300. A factorial design was used such that participants were asked to cycle with and without conscious effort with and without stimulation. We used mixed effects models assessing maximum power output and time pedaling unassisted to evaluate the interaction between stimulation and conscious effort. Cycling was well-tolerated and we observed no adverse events, including in participants up to 17 years post-initial injury and up to 58 years old. All participants were found to be able to pedal without motor assist, which primarily occurred when stimulation and effort were applied together (p = 0.001). Additionally, the combination of stimulation and intention was significantly associated with higher maximum power production (p < 0.0001) and distance pedaled (p = 0.0001). No association was found between volitional movement and participant factors: age, time since injury, and spinal cord atrophy. With stimulation and conscious effort, all participants were able to achieve active cycling without motor assistance. Thus, our stationary cycling factorial study design demonstrated volitional movement restoration with eSCS in a diverse study population of cSCI participants. Further, motor-assist cycling was well-tolerated without any adverse events. Cycling has the potential to be a safe research assessment and physical therapy modality for cSCI patients utilizing eSCS who have a high risk of injury with weight bearing exercise. The cycling modality in this study was demonstrated to be a straightforward assessment of motor function and safe for all participants regardless of age or time since initial injury.

Pharmacologic and nonpharmacologic treatment modalities for bone loss in SCI - Proposal for combined approach

Increased risk of bone fracture due to bone mineral density (BMD) loss is a serious consequence of spinal cord injury (SCI). Traditionally, pharmaceutical approaches, such as bisphosphonates, have been prescribed to prevent bone loss. However, there is controversy in the literature regarding efficacy of these medications to mitigate the drastic bone loss following SCI. Individuals with SCI are particularly at risk of osteoporosis because of the lack of ambulation and weight bearing activities. In the past two decades, functional electric stimulation (FES) has allowed for another approach to treat bone loss. FES approaches are expanding into various modalities such as cycling and rowing exercises and show promising outcomes with minimal consequences. In addition, these non-pharmacological treatments can elevate overall physical and mental health. This article provides an overview of efficacy of different treatment options for BMD loss for SCI and advocates for a combined approach be pursued in standard of care.

Effect of epidural spinal cord stimulation after chronic spinal cord injury on volitional movement and cardiovascular function: study protocol for the phase II open label controlled E-STAND trial

INTRODUCTION

Spinal cord injury (SCI) leads to significant changes in morbidity, mortality and quality of life (QOL). Currently, there are no effective therapies to restore function after chronic SCI. Preliminary studies have indicated that epidural spinal cord stimulation (eSCS) is a promising therapy to improve motor control and autonomic function for patients with chronic SCI. The aim of this study is to assess the effects of tonic eSCS after chronic SCI on quantitative outcomes of volitional movement and cardiovascular function. Our secondary objective is to optimise spinal cord stimulation parameters for volitional movement.

METHODS AND ANALYSIS

The Epidural Stimulation After Neurologic Damage (ESTAND) trial is a phase II single-site self-controlled trial of epidural stimulation with the goal of restoring volitional movement and autonomic function after motor complete SCI. Participants undergo epidural stimulator implantation and are followed up over 15 months while completing at-home, mobile application-based movement testing. The primary outcome measure integrates quantity of volitional movement and similarity to normal controls using the volitional response index (VRI) and the modified Brain Motor Control Assessment. The mobile application is a custom-designed platform to support participant response and a kinematic task to optimise the settings for each participant. The application optimises stimulation settings by evaluating the parameter space using movement data collected from the tablet application and accelerometers. A subgroup of participants with cardiovascular dysautonomia are included for optimisation of blood pressure stabilisation. Indirect effects of stimulation on cardiovascular function, pain, sexual function, bowel/bladder, QOL and psychiatric measures are analysed to assess generalisability of this targeted intervention.

ETHICS AND DISSEMINATION

This study has been approved after full review by the Minneapolis Medical Research Foundation Institutional Review Board and by the Minneapolis VA Health Care System. This project has received Food and Drug Administration investigational device exemption approval. Trial results will be disseminated through peer-reviewed publications, conference presentations and seminars.

TRIAL REGISTRATION NUMBER

NCT03026816.

The safety of epidural spinal cord stimulation to restore function after spinal cord injury: post-surgical complications and incidence of cardiovascular events

STUDY DESIGN

Cohort prospective study.

OBJECTIVES

Epidural spinal cord stimulation (eSCS) improves volitional motor and autonomic function after spinal cord injury (SCI). While eSCS has an established history of safety for chronic pain, it remains unclear if eSCS in the SCI population presents the same risk profile. We aimed to assess safety and autonomic monitoring data for the first 14 participants in the E-STAND trial.

SETTING

Hennepin County Medical Center, Minneapolis and Minneapolis Veterans Affairs Medical Center, Minnesota, USA.

METHODS

Monthly follow-up visits assessed surgical and medical device-related safety outcomes as well as stimulation usage. Beat-by-beat blood pressure (BP) and continuous electrocardiogram data were collected during head-up tilt-table testing with and without eSCS.

RESULTS

All participants had a motor-complete SCI. Mean (SD) age and time since injury were 38 (10) and 7 (5) years, respectively. There were no surgical complications but one device malfunction 4 months post implantation. Stimulation was applied for up to 23 h/day, across a broad range of parameters: frequency (18-700 Hz), pulse width (100-600 µs), and amplitude (0.4-17 mA), with no adverse events reported. Tilt-table testing with eSCS demonstrated no significant increases in the incidence of elevated systolic BP or a greater frequency of arrhythmias.

CONCLUSIONS

eSCS to restore autonomic and volitional motor function following SCI has a similar safety profile as when used to treat chronic pain, despite the prevalence of significant comorbidities and the wide variety of stimulation parameters tested.

Long-Term Spinal Cord Stimulation After Chronic Complete Spinal Cord Injury Enables Volitional Movement in the Absence of Stimulation

Background: Chronic spinal cord injury (SCI) portends a low probability of recovery, especially in the most severe subset of motor-complete injuries. Active spinal cord stimulation with or without intensive locomotor training has been reported to restore movement after traumatic SCI. Only three cases have been reported where participants developed restored volitional movement with active stimulation turned off after a period of chronic stimulation and only after intensive rehabilitation with locomotor training. It is unknown whether restoration of movement without stimulation is possible after stimulation alone.

Objective: We describe the development of spontaneous volitional movement (SVM) without active stimulation in a subset of participants in the Epidural Stimulation After Neurologic Damage (ESTAND) trial, in which locomotor training is not prescribed as part of the study protocol, and subject’s rehabilitation therapies are not modified.

Methods: Volitional movement was evaluated with the Brain Motor Control Assessment using sEMG recordings and visual examination at baseline and at follow-up visits with and without stimulation. Additional functional assessment with a motor-assisted bicycle exercise at follow-up with and without stimulation identified generated work with and without effort.

Results: The first seven participants had ASIA Impairment Scale (AIS) A or B thoracic SCI, a mean age of 42 years, and 7.7 years post-injury on average. Four patients developed evidence of sustained volitional movement, even in the absence of active stimulation after undergoing chronic epidural spinal cord stimulation (eSCS). Significant increases in volitional power were found between those observed to spontaneously move without stimulation and those unable (p < 0.0005). The likelihood of recovery of spontaneous volitional control was correlated with spasticity scores prior to the start of eSCS therapy (p = 0.048). Volitional power progressively improved over time (p = 0.016). Additionally, cycling was possible without stimulation (p < 0.005).

Conclusion: While some SVM after eSCS has been reported in the literature, this study demonstrates sustained restoration without active stimulation after long-term eSCS stimulation in chronic and complete SCI in a subset of participants. This finding supports previous studies suggesting that “complete” SCI is likely not as common as previously believed, if it exists at all in the absence of transection and that preserved pathways are substrates for eSCS-mediated recovery in clinically motor-complete SCI.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier NCT03026816.

Epidural Spinal Cord Stimulation Facilitates Immediate Restoration of Dormant Motor and Autonomic Supraspinal Pathways after Chronic Neurologically Complete Spinal Cord Injury

Epidural Spinal Cord Stimulation (eSCS) in combination with extensive rehabilitation has been reported to restore volitional movement in a select group of subjects after motor-complete spinal cord injury (SCI). Numerous questions about the generalizability of these findings to patients with longer term SCI have arisen, especially regarding the possibility of restoring autonomic function. To better understand the effect of eSCS on volitional movement and autonomic function, two female participants five and 10 years after injury at ages 48 and 52, respectively, with minimal spinal cord preservation on magnetic resonance imaging were implanted with an eSCS system at the vertebral T12 level. We demonstrated that eSCS can restore volitional movement immediately in two female participants in their fifth and sixth decade of life with motor and sensory-complete SCI, five and 10 years after sustaining severe radiographic injuries, and without prescribed or significant pre-habilitation. Both patients experienced significant improvements in surface electromyography power during a volitional control task with eSCS on. Cardiovascular function was also restored with eSCS in one participant with cardiovascular dysautonomia using specific eSCS settings during tilt challenge while not affecting function in a participant with normal cardiovascular function. Orgasm was achieved for the first time since injury in one participant with and immediately after eSCS. Bowel-bladder synergy improved in both participants while restoring volitional urination in one with eSCS. While numerous questions remain, the ability to restore some supraspinal control over motor function below the level of injury, cardiovascular function, sexual function, and bowel and bladder function should promote intense efforts to investigate and develop optimization strategies to maximize recovery in all participants with chronic SCI.

Improving training in spiritual care: a qualitative study exploring patient perceptions of professional educational requirements

Healthcare professionals express difficulties in delivering spiritual care, despite it being a core component of palliative care national policies. The patient perspective on professional training to address difficulties has not previously been sought. The aim of this study is to describe patient suggestions for development of training to deliver spiritual care. Qualitative semi-structured in-depth 'palliative patient' interviews (n = 20) were analysed thematically. Training suggestions encompassed practical care delivery. Patients supported staff who introduced questions about spiritual needs, and they expected opportunities to engage in spiritual care discussions. The 'right' attitude for spiritual care delivery was defined as being non-judgemental, providing integrated care and showing interest in individuals. Training issues included patient perspectives of boundaries between personal and professional roles. This study provides 'palliative patient' perspectives to strengthen recommended models of spiritual care delivery. It shows that user opinions on training can be helpful not only in deciding objectives but also how to achieve them.

Adult spinal cord stem/progenitor cells transplanted as neurospheres preferentially differentiate into oligodendrocytes in the adult rat spinal cord

Neural stem/progenitor cells (NSPCs) capable of generating new neurons and glia reside in the adult mammalian spinal cord. Transplantation of NSPCs has therapeutic potential for spinal cord injury, although there is limited information on the ability of these cells to survive and differentiate in vivo. Neurospheres cultured from the periventricular region of the adult spinal cord contain NSPCs that are self-renewing and multipotent. We examined the survival, proliferation, migration, and differentiation of adult spinal cord NSPCs generated from green fluorescent protein (GFP) transgenic rats and transplanted into the intact spinal cord. The grafted GFP-expressing cells survived for at least 6 weeks in vivo and migrated from the injection site along the rostro-caudal axis of the spinal cord. Transplanted cells transiently proliferated following transplantation and approximately 17% of the GFP-positive cells were apoptotic at 1 day. Also, better survival was seen with NSPCs transplanted as neurospheres in comparison to NSPCs transplanted as dissociated cells. By 1 week posttransplantation, grafted cells primarily expressed an oligodendrocytic phenotype and only 2% differentiated into astrocytes. Approximately 75% versus 38% of the grafted cells differentiated into oligodendrocytes after transplantation into spinal white versus gray matter, respectively. This is the first report to examine the time course of cell survival, proliferation, apoptosis, and phenotypic differentiation of transplanted NSPSs in the spinal cord. This is also the first report to examine the differences between transplanted NSPCs grafted as neurospheres or dissociated cells, and to compare the differentiation potential after transplantation into spinal cord white versus gray matter.

Gene expression profile of enzymes involved in gemcitabine (Gem) metabolism in bone marrow mononuclear cells as predictors of myelosuppression

2007

Background: The dose-limiting toxicity of gemcitabine (Gem) is hematologic toxicity (heme tox), and there is wide intra-patient variability in the degree of heme tox. This study was done to assess the possible impact of gene expression of enzymes involved in Gem metabolism or mechanism of action on heme tox. Methods: Pre-therapy mononuclear cells were isolated from bone marrow aspirates collected from 71 consenting patients with various advanced malignancies enrolled in an IRB-approved phase I trial in which single agent Gem was given over 30 min weekly for 2 of 3 weeks during cycle 1 at doses ranging from 750–1,560 mg/m2. Gene expression of deoxycytidine kinase (DCK), an activating enzyme, cytidine deaminase (CD) and deoxycytidylate deaminase (DCD), deactivating enzymes, and ribonucleotide reductase M2 (RNR), which is inhibited by Gem diphosphate, was measured by real-time RT-PCR. Target gene expression was relative to beta-actin. Heme tox was calculated as the % decrease in white blood cells (WBC), neutrophils (ANC) and platelets (PLT) from baseline. Results: 71 patients (26 females, 35 males) with a median age of 56 years (range: 20–75) were included in the analysis. The median (25th %, 75th %) gene expression was as follows (x10e3/beta-actin): DCK, 0.34 (0.19, 0.64); CD, 1.88 (1.33, 2.92); DCD, 2.48 (1.15, 7.78); and RNR, 0.39 (0.19, 0.80). A strong linear correlation was noted only between RNR & DCD gene expression (Pearson r = 0.89). When gene expression was categorized as above or below the median value, only CD appeared to influence heme tox (mean ± std dev) ( Table ). T-test p value is shown. Conclusions: Gem is rapidly metabolized to its inactive metabolite by CD. Subjects with a higher relative gene expression of CD tended to have a lesser degree of heme tox following Gem. Correlation with Gem pharmacokinetics in these subjects is planned.

[Table: see text]

No significant financial relationships to disclose.

Induction of hydroxycinnamoyl-tyramine conjugates in pepper by Xanthomonas campestris, a plant defense response activated by hrp gene-dependent and hrp gene-independent mechanisms

Inoculation of pepper leaves, Capsicum annuum cv. Early Calwonder ECW 10R, with strains of Xanthomonas campestris led to an accumulation of the phenolic conjugates feruloyltyramine (FT) and p-coumaroyltyramine (CT) 24 h postinoculation in nonhost- and gene-for-gene-determined incompatible interactions with X. campestris pv. campestris and X. campestris pv. vesicatoria, respectively. In contrast, neither compound was detected in compatible interactions with X. campestris pv. vesicatoria. The accumulation of FT and CT was preceded by an increase in the extractable activity of tyrosine decarboxylase as well as increases in the transcription of genes encoding phenylalanine ammonia-lyase and tyramine hydroxycinnamoyl transferase. No such changes were detected in compatible interactions. Very rapid accumulation of FT and CT occurred (4 h postinoculation) in pepper in response to a X. campestris pv. campestris mutant carrying a deletion of the hrp gene cluster. In contrast, hrp mutants of X. campestris pv. vesicatoria failed to elicit the production of FT and CT. These observations suggest the existence of hrp gene-dependent and -independent activation mechanisms of a defense response involving hydroxycinnamoyltyramines.

Thymidine kinase, thymidylate synthase, and dihydropyrimidine dehydrogenase profiles of cell lines of the National Cancer Institute's Anticancer Drug Screen

PURPOSE

To determine the expression of three targets of 5-fluorouracil (5-FU) and 5-fluoro-2'-deoxyuridine (FdUrd) in human tumor cell lines and to compare these with the 50% growth inhibition concentrations (GI(50)) from the National Cancer Institute database.

EXPERIMENTAL DESIGN

Thymidine kinase (TK) activity was assessed by conversion of [(3)H]thymidine to [(3)H]TMP. Thymidylate synthase (TS) protein expression was determined by Western analysis. TS and dihydropyrimidine dehydrogenase (DPD) mRNA expression were measured by quantitative reverse transcription-PCR.

RESULTS

The median (range) for the targets were as follows: 5-FU GI(50), 20.8 microM (0.8-536); FdUrd GI(50), 0.75 microM (0.25-237); TK, 0.93 nmol/min/mg (0.16-5.7); in arbitrary units: TS protein, 0.41 (0.05-2.95); TS mRNA, 1.05 (0.12-6.41); and DPD mRNA, 1.09 (0.00-24.4). A moderately strong correlation was noted between 5-FU and FdUrd GI(50)s (r = 0.60), whereas a weak-moderate correlation was seen between TS mRNA and protein expression (r = 0.45). Neither TS expression nor TK activity correlated with 5-FU or FdUrd GI(50)s, whereas lines with lower DPD expression tended to be more sensitive to 5-FU. Cell lines with faster doubling times and wild-type p53 were significantly more sensitive to 5-FU and FDURD:

CONCLUSIONS

The lack of correlation may in part be attributable to the influence of downstream factors such as p53, the observation that the more sensitive cell lines with faster doubling times also had higher TS levels, and the standard procedure of the screen that uses a relatively short (48-h) drug exposure.

The prognostic value of molecular marker analysis in patients treated with trimodality therapy for esophageal cancer

The purpose of this study was to define the prognostic value of a group of molecular tumor markers in a well-staged population of patients treated with trimodality therapy for esophageal cancer. The original pretreatment paraffin-embedded endoscopic esophageal tumor biopsy material was obtained from 118 patients treated with concurrent cisplatin + 5-fluorouracil (5-FU) + 45 Gy radiation followed by resection from 1986 until 1997 at the Duke University Comprehensive Cancer Center. Three markers of possible platinum chemotherapy association [metallothionein (MT), glutathione S-transferase-pi (GST-pi), P-glycoprotein (P-gp or multidrug resistance)] and one marker of possible 5-FU association [thymidylate synthase (TS)] were measured using immunohistochemistry. The median cancer-free survival was 25.0 months, with a significantly improved survival for the 38 patients who had a complete response (P < 0.001). High-level expression of GST-pi, P-gp, and TS were associated with a decreased survival. MT was not significant in this population. Multivariate analysis identified high-level expression in two of the platinum markers (GST-pi and P-gp) and the 5-FU marker TS as independent predictors of early recurrence and death. In conclusion, this investigation measured three possible markers associated with platinum and one possible marker associated with 5-FU in a cohort of esophageal cancer patients. Independent prognostic significance was observed, which suggests that it may be possible to predict which patients may benefit most from trimodality therapy. These data need to be reproduced in a prospective investigation.

Identification of glucosyltransferase genes involved in sinapate metabolism and lignin synthesis in Arabidopsis

Sinapic acid is a major phenylpropanoid in Brassicaceae providing intermediates in two distinct metabolic pathways leading to sinapoyl esters and lignin synthesis. Glucosyltransferases play key roles in the formation of these intermediates, either through the production of the high energy compound 1-O-sinapoylglucose leading to sinapoylmalate and sinapoylcholine or through the production of sinapyl alcohol-4-O-glucoside, potentially leading to the syringyl units found in lignins. While the importance of these glucosyltransferases has been recognized for more than 20 years, their corresponding genes have not been identified. Combining sequence information in the Arabidopsis genomic data base with biochemical data from screening the activity of recombinant proteins in vitro, we have now identified five gene sequences encoding enzymes that can glucosylate sinapic acid, sinapyl alcohol, and their related phenylpropanoids. The data provide a foundation for future understanding and manipulation of sinapate metabolism and lignin biology in Arabidopsis.

Transcriptional repression by AtMYB4 controls production of UV-protecting sunscreens in Arabidopsis

An Arabidopsis thaliana line that is mutant for the R2R3 MYB gene, AtMYB4, shows enhanced levels of sinapate esters in its leaves. The mutant line is more tolerant of UV-B irradiation than wild type. The increase in sinapate ester accumulation in the mutant is associated with an enhanced expression of the gene encoding cinnamate 4-hydroxylase, which appears to be the principal target of AtMYB4 and an effective rate limiting step in the synthesis of sinapate ester sunscreens. AtMYB4 expression is downregulated by exposure to UV-B light, indicating that derepression is an important mechanism for acclimation to UV-B in A.thaliana. The response of target genes to AtMYB4 repression is dose dependent, a feature that operates under physiological conditions to reinforce the silencing effect of AtMYB4 at high activity. AtMYB4 works as a repressor of target gene expression and includes a repression domain. It belongs to a novel group of plant R2R3 MYB proteins involved in transcriptional silencing. The balance between MYB activators and repressors on common target promoters may provide extra flexibility in transcriptional control.

Salicylic acid is not required for Cf-2- and Cf-9-dependent resistance of tomato to Cladosporium fulvum

Tomato leaves or cotyledons expressing the Cf-2 or Cf-9 Cladosporium fulvum resistance genes induce salicylic acid (SA) synthesis following infiltration with intercellular washing fluid (IF) containing the fungal peptide elicitors Avr2 and Avr9. We investigated whether SA was required for Cf gene-dependent resistance. Tomato plants expressing the bacterial gene nahG, encoding salicylate hydroxylase, did not accumulate SA in response to IF infiltration but remained fully resistant to C. fulvum. NahG Cf0 plants were as susceptible to C. fulvum as wild-type Cf0. Neither free nor conjugated salicylic acid accumulated in IF-infiltrated Cf2 and Cf9 NahG leaves and cotyledons but conjugated catechol did accumulate. The Cf-9-dependent necrotic response to IF was prevented in NahG plants and replaced by a chlorotic Cf-2-like response. SA also potentiated Cf-9-mediated necrosis in IF-infiltrated wild-type leaves. In contrast, the Cf-2-dependent IF response was retained in NahG leaves and chlorosis was more pronounced than in the wild-type. The distribution of cell death between different cell types was altered in both Cf2 and Cf9 NahG leaves after IF injection. IF-induced accumulation of three SA-inducible defence-related genes was delayed and reduced but not abolished in NahG Cf2 and Cf9 leaves and cotyledons. NahG Tm-22 tomato showed increased hypersensitive response (HR) lesion size upon TMV infection, as observed in TMV-inoculated N gene-containing NahG tobacco plants.

Genetic analysis and enzyme activity suggest the existence of more than one minimal functional unit capable of synthesizing phosphoribosyl pyrophosphate in Saccharomyces cerevisiae

The PRS gene family in Saccharomyces cerevisiae consists of five genes each capable of encoding a 5-phosphoribosyl-1(alpha)-pyrophosphate synthetase polypeptide. To gain insight into the functional organization of this gene family we have constructed a collection of strains containing all possible combinations of disruptions in the five PRS genes. Phenotypically these deletant strains can be classified into three groups: (i) a lethal phenotype that corresponds to strains containing a double disruption in PRS2 and PRS4 in combination with a disruption in either PRS1 or PRS3; simultaneous deletion of PRS1 and PRS5 or PRS3 and PRS5 are also lethal combinations; (ii) a second phenotype that is encountered in strains containing disruptions in PRS1 and PRS3 together or in combination with any of the other PRS genes manifests itself as a reduction in growth rate, enzyme activity, and nucleotide content; (iii) a third phenotype that corresponds to strains that, although affected in their phosphoribosyl pyrophosphate-synthesizing ability, are unimpaired for growth and have nucleotide profiles virtually the same as the wild type. Deletions of PRS2, PRS4, and PRS5 or combinations thereof cause this phenotype. These results suggest that the polypeptides encoded by the members of the PRS gene family may be organized into two functional entities. Evidence that these polypeptides interact with each other in vivo was obtained using the yeast two-hybrid system. Specifically PRS1 and PRS3 polypeptides interact strongly with each other, and there are significant interactions between the PRS5 polypeptide and either the PRS2 or PRS4 polypeptides. These data suggest that yeast phosphoribosyl pyrophosphate synthetase exists in vivo as multimeric complex(es).

PRS5, the fifth member of the phosphoribosyl pyrophosphate synthetase gene family in Saccharomyces cerevisiae, is essential for cell viability in the absence of either PRS1 or PRS3

In Saccharomyces cerevisiae, an open reading frame, YOL061w, encodes a polypeptide with sequence similarity to the four known 5-phosphoribosyl-1(alpha)-pyrophosphate synthetase (PRS) genes since it contains a divalent cation binding site and a phosphoribosyl pyrophosphate binding site. We regard YOL061w as the fifth member of the PRS gene family, PRS5. Loss of Prs5p has a significant impact on PRS enzyme activity, causing it to be reduced by 84%. On the other hand, Deltaprs5 strains are not affected in growth or in the size of their nucleotide pools. However, simultaneous deletion of PRS1 and PRS5 or PRS3 and PRS5 rendered the strains inviable, which implies that PRS5 plays an important role in the maintenance of PRS function in S. cerevisiae.

Inhibition of phenolic acid metabolism results in precocious cell death and altered cell morphology in leaves of transgenic tobacco plants

Several complex phenotypic changes are induced when the transcription factor AmMYB308 is overexpressed in transgenic tobacco plants. We have previously shown that the primary effect of this transcription factor is to inhibit phenolic acid metabolism. In the plants that we produced, two morphological features were prominent: abnormal leaf palisade development and induction of premature cell death in mature leaves. Evidence from the analysis of these transgenic plants suggests that both changes resulted from the lack of phenolic intermediates. These results emphasize the importance of phenolic secondary metabolites in the normal growth and development of tobacco. We suggest that phenolic acid derivatives are important signaling molecules in the final stages of leaf palisade formation and that phenolic acid derivatives also play a prominent role in tissue senescence.

Inhibition of phenolic acid metabolism results in precocious cell death and altered cell morphology in leaves of transgenic tobacco plants

Several complex phenotypic changes are induced when the transcription factor AmMYB308 is overexpressed in transgenic tobacco plants. We have previously shown that the primary effect of this transcription factor is to inhibit phenolic acid metabolism. In the plants that we produced, two morphological features were prominent: abnormal leaf palisade development and induction of premature cell death in mature leaves. Evidence from the analysis of these transgenic plants suggests that both changes resulted from the lack of phenolic intermediates. These results emphasize the importance of phenolic secondary metabolites in the normal growth and development of tobacco. We suggest that phenolic acid derivatives are important signaling molecules in the final stages of leaf palisade formation and that phenolic acid derivatives also play a prominent role in tissue senescence.

New monoclonal antibodies to the T cell antigens CD4 and CD8. Production and characterization in formalin-fixed paraffin-embedded tissue

We have generated a recombinant protein representing part of the CD4 molecule and a peptide representing an epitope of predicted high antigenicity on the CD8 molecule and employed these to generate mouse monoclonal antibodies using standard hybridoma protocols. The extracellular domain of the CD4 molecule was obtained by reverse transcription of mRNA from peripheral blood lymphocytes followed by polymerase chain reaction. The amplified gene fragment was cloned into an expression vector to allow a histidine-tagged fusion protein to be produced in Escherichia coli. Purified fusion protein was used to immunize mice. The CD8 monoclonal antibody was raised against a peptide consisting of 13 amino acids within the carboxyl-terminal region of the CD8 cytoplasmic domain. The antibodies showed appropriate reactivity on Western blotting. By heat pretreatment, these antibodies have been shown to be highly effective on paraffin-embedded tissue. In normal lymphoid tissue, the expected distribution of CD4 and CD8 lymphocytes was observed. In a series of 16 T cell lymphomas and B cell lymphomas, immunostaining results were compared with those obtained using reagents effective only in frozen tissue. A high degree of correlation was observed. These results suggest that NCL-CD4 and NCL-CD8 may be of value in the characterization of T cell disorders.

Structural analyses and dynamics of soluble and cell wall-bound phenolics in a broad spectrum resistance to the powdery mildew fungus in barley

High pressure liquid chromatography profiles of barley leaf epidermal soluble and cell wall-bound phenolics were analyzed in response to challenge with the fungal pathogen Erysiphe graminis f. sp. hordei. Only one soluble phenolic was found to accumulate differentially in a broad spectrum resistance reaction controlled by mlo resistance alleles in comparison to susceptible near isogenic Mlo lines. Structural analysis identified this compound as a novel phenolic conjugate, p-coumaroyl-hydroxyagmatine (p-CHA). p-CHA but not the nonhydroxylated derivative p-coumaroylagmatine exhibited antifungal activity both in vitro and in vivo. The accumulation of p-CHA in epidermal tissue correlated tightly with fungal penetration attempts of attacked host cells. Furthermore, upon penetration, epidermal cell wall-bound phenolics became resistant to saponification at sites of attempted fungal ingress (papilla), indicating a change in, or the addition of, different chemical bonding types. The switch in saponification sensitivity occurred at least 2 h earlier in the mlo-incompatible than in the Mlo-compatible interaction. Our results suggest that p-CHA and the speed of papillae compaction play important roles in non-race-specific powdery mildew defense.

Structural analyses and dynamics of soluble and cell wall-bound phenolics in a broad spectrum resistance to the powdery mildew fungus in barley

High pressure liquid chromatography profiles of barley leaf epidermal soluble and cell wall-bound phenolics were analyzed in response to challenge with the fungal pathogen Erysiphe graminis f. sp. hordei. Only one soluble phenolic was found to accumulate differentially in a broad spectrum resistance reaction controlled by mlo resistance alleles in comparison to susceptible near isogenic Mlo lines. Structural analysis identified this compound as a novel phenolic conjugate, p-coumaroyl-hydroxyagmatine (p-CHA). p-CHA but not the nonhydroxylated derivative p-coumaroylagmatine exhibited antifungal activity both in vitro and in vivo. The accumulation of p-CHA in epidermal tissue correlated tightly with fungal penetration attempts of attacked host cells. Furthermore, upon penetration, epidermal cell wall-bound phenolics became resistant to saponification at sites of attempted fungal ingress (papilla), indicating a change in, or the addition of, different chemical bonding types. The switch in saponification sensitivity occurred at least 2 h earlier in the mlo-incompatible than in the Mlo-compatible interaction. Our results suggest that p-CHA and the speed of papillae compaction play important roles in non-race-specific powdery mildew defense.

The AmMYB308 and AmMYB330 transcription factors from antirrhinum regulate phenylpropanoid and lignin biosynthesis in transgenic tobacco

MYB-related transcription factors are known to regulate different branches of flavonoid metabolism in plants and are believed to play wider roles in the regulation of phenylpropanoid metabolism in general. Here, we demonstrate that overexpression of two MYB genes from Antirrhinum represses phenolic acid metabolism and lignin biosynthesis in transgenic tobacco plants. The inhibition of this branch of phenylpropanoid metabolism appears to be specific to AmMYB308 and AmMYB330, suggesting that they recognize their normal target genes in these transgenic plants. Experiments with yeast indicate that AmMYB308 can act as a very weak transcriptional activator so that overexpression may competitively inhibit the activity of stronger activators recognizing the same target motifs. The effects of the transcription factors on inhibition of phenolic acid metabolism resulted in complex modifications of the growth and development of the transgenic plants. The inhibition of monolignol production resulted in plants with at least 17% less lignin in their vascular tissue. This reduction is of importance when designing strategies for the genetic modification of woody crops.

The AmMYB308 and AmMYB330 transcription factors from antirrhinum regulate phenylpropanoid and lignin biosynthesis in transgenic tobacco

MYB-related transcription factors are known to regulate different branches of flavonoid metabolism in plants and are believed to play wider roles in the regulation of phenylpropanoid metabolism in general. Here, we demonstrate that overexpression of two MYB genes from Antirrhinum represses phenolic acid metabolism and lignin biosynthesis in transgenic tobacco plants. The inhibition of this branch of phenylpropanoid metabolism appears to be specific to AmMYB308 and AmMYB330, suggesting that they recognize their normal target genes in these transgenic plants. Experiments with yeast indicate that AmMYB308 can act as a very weak transcriptional activator so that overexpression may competitively inhibit the activity of stronger activators recognizing the same target motifs. The effects of the transcription factors on inhibition of phenolic acid metabolism resulted in complex modifications of the growth and development of the transgenic plants. The inhibition of monolignol production resulted in plants with at least 17% less lignin in their vascular tissue. This reduction is of importance when designing strategies for the genetic modification of woody crops.

Motor recovery after stroke depends on intact sustained attention: a 2-year follow-up study

The functional recovery of 47 right-brain-damaged stroke patients was studied over a 2-year period. The researchers hypothesized that sustained attention capacity should predict the degree of motor and functional recovery over this period because of a proposed privileged role of sustained attention in learning-based recovery of function. As predicted, significant correlations were found between sustained attention capacity at 2 months and functional status (including the Barthel Index) at 2 years. This relationship was shown to exist independently of 2-month functional status. Furthermore, compared with a left-brain-damaged group of cerebrovascular accident (CVA) patients, the right-brain CVA group did not recover functional ability as well over the 2-year period. This increasing difference in functional status over a 2-year period was mirrored by an emerging difference in sustained attention capacity, in favor of the left-brain CVA group.

Motor recovery after stroke depends on intact sustained attention: a 2-year follow-up study

The functional recovery of 47 right-brain-damaged stroke patients was studied over a 2-year period. The researchers hypothesized that sustained attention capacity should predict the degree of motor and functional recovery over this period because of a proposed privileged role of sustained attention in learning-based recovery of function. As predicted, significant correlations were found between sustained attention capacity at 2 months and functional status (including the Barthel Index) at 2 years. This relationship was shown to exist independently of 2-month functional status. Furthermore, compared with a left-brain-damaged group of cerebrovascular accident (CVA) patients, the right-brain CVA group did not recover functional ability as well over the 2-year period. This increasing difference in functional status over a 2-year period was mirrored by an emerging difference in sustained attention capacity, in favor of the left-brain CVA group.

Structure-function relations of variant and fragment nisins studied with model membrane systems

Nisin, a 34 residue lantibiotic produced by strains of Lactococcus lactis subsp. lactis, exerts antimicrobial activity against Gram-positive bacteria at the cytoplasmic membrane. The structural aspects of nisin which facilitate membrane interaction and permeabilization have been investigated in planar lipid bilayers and liposomes with proteolytic fragments and site-directed variants. N-Terminal nisin fragments N1-12 and N1-20 had little effect on phospholipid mobility, on macroscopic electrical conductance, or on calcein release from liposomes. By contrast, the I30W nisin A variant induced a time-dependent reduction in lipid mobility, indicative of nisin-membrane surface interactions, as well as a decline in membrane capacitance, rise in conductance, and calcein release from liposomes. In these respects I30W nisin A is similar to native nisin. Charge substitutions were also engineered to generate K12L and H27K nisin A variants, both of which were similar to I30W nisin A with respect to an overall reduction in phospholipid mobility. While the K12L nisin A variant elicited a higher increase in membrane capacitance and electrical conductance than I30W nisin A, the H27K nisin A variant elicited weaker effects. These results point to a substantial role for intramembrane charged residues in controlling ion flow through nisin-doped membranes. Native nisin and variants elicit an enhanced release of calcein from liposomes composed of the negatively-charged phospholipids cardiolipin and phosphatidylserine, compared with phospholipid bearing no net charge, suggesting that an electrostatic attraction encourages the initial nisin-membrane association. The results are discussed in the context of other recently proposed models for nisin action.

OCT embedded sections of pathological specimens as a source of high quality RNA for reverse transcriptase/polymerase chain reaction

OCT embedded cryostat sections of stored pathological specimens of non-Hodgkin's lymphoma were used to provide RNA. After reverse transcription to produce cDNA, the polymerase chain reaction was performed with primers for standard and variant forms of the CD44 molecule. Using Southern transfer and hybridisation with a probe specific for exon 4 of the CD44 gene, both standard and variant forms were visualised by autoradiography. This method was shown to be applicable to other gene products by using primers specific for the abl and bcr genes. This technique permits retrospective analysis of RNA from small amounts of stored pathological samples.

Assessment of hepatitis B "e" antigen and "e" antibody status--tests of status or status of tests?

Forty-seven sera that gave positive results in tests for hepatitis B surface antigen and core antibody were examined for the presence of "e" antigen and "e" antibody by various commercially available assays. Considerable discordance was observed between results of tests performed on the same sample in different assays. Examination of the sera for the presence of hepatitis B DNA failed to resolve the discrepancies. Increasingly, "e" antigen and its antibody are used as measures of infectivity in carriers of hepatitis B. The absence of reliable tests has implications for patients, for infection control within hospitals and for the implementation of Department of Health guidelines on safe working practices for hepatitis B-infected health care workers.

Rayleigh scattering limits for low-level bidirectional reflectance distribution function measurements

The objective is to estimate the Rayleigh limit in bidirectional reflectance distribution function (BRDF) measurements caused by air in the laboratory, the wavelength, and the path length of light in the receiver field of view. Moreover, we intend to show the trend for the reduction of this limit by introducing a medium with small refractive index and by using a longer wavelength. Although the BRDF typically describes the angular distribution of scattered light from surfaces, the expression describing the equivalent BRDF caused by the optical scattering from gas molecules in the optical path is derived through the use of the Rayleigh scattering theory. The instrumentation is described, and the experimental results of the equivalent BRDF caused by gas scattering from molecules in clear air, nitrogen, and helium gases are reported. These results confirm the trends of the prediction.

Delineation of translocation t(15; 17) in acute promyelocytic leukemia by chromosomal in situ suppression hybridization

In this study we demonstrate the feasibility of chromosomal in situ suppression (CISS) hybridization to detect the translocation t(15; 17) in metaphase spreads of patients with acute promyelocytic leukemia. Using DNA libraries from sorted human chromosomes 15 and 17 the translocation t(15; 17) can be unequivocally identified even if the spread and the morphology of the chromosomes are poor. The sensitivity of CISS hybridization is compared with the sensitivity of conventional G-banded karyotypes.

Seven variants including four new Philadelphia translocations

This paper reports on seven atypical Philadelphia chromosome translocations in chronic myelocytic leukemia. Three of them, a t(16;22), t(17;22), and t(9;14;22) have already been observed before, while the t(X;9;11;22), t(X;22), t(3;22) and t(3;4;9;22) are newly reported.

Radiolabeling of intact dosage forms by neutron activation: effects on in vitro performance

Compressed tablets containing various quantities of stable isotopes of Ba, Er, and Sm for use in neutron activation studies were evaluated for the effect of stable isotope incorporation on tablet hardness and disintegration times. At concentrations likely to be used in scintigraphic studies employing neutron activation as a radiolabeling method, no significant effect on in vitro parameters were observed. While the incorporation of stable isotopes influenced tablet hardness to a greater degree than disintegration time, irradiation of tablets in a neutron flux of 4.4 x 10(13) n/cm2 sec had a direct effect on tablet disintegration time. Thus, future neutron activation studies should focus on minimizing the amount of stable isotope to be incorporated with the formulation while using the shortest feasible irradiation time.