The Problem of Pain in Lupus: Epidemiological Profiles of Patients Attending Multidisciplinary Pain Clinics

INTRODUCTION

Patients with systemic lupus erythematosus (SLE) bear a significant burden of pain. We aimed to identify factors that distinguish patients with SLE referred to comprehensive pain clinics and those who are not. Characterizing this patient population will identify unmet needs in SLE management and inform efforts to improve pain care in rheumatology.

METHODS

Among patients with SLE with ≥2 rheumatology clinic visits in a large hospital system from 1998 to 2023 (n = 1319), we examined factors that distinguished those who had at least one visit to multidisciplinary pain clinics (n = 77, 5.8%) from those who did not have any visits (n = 1242, 94.2%) with a focus on biopsychosocial and socioeconomic characteristics. We extracted demographic data and ICD-9/ICD-10 codes from the EHR.

RESULTS

Patients with SLE attending the pain clinics exhibited characteristics including average older age (mean age ± SD: 54.1 ± 17.9 vs. 48.4 ± 19.9), a higher likelihood of relying on public health insurance (50.7% vs. 34.2%), and a greater representation of Black patients (9.1% vs. 4.4%) compared to SLE patients not seen in pain clinics. Nearly all patients seen at the pain clinics presented with at least one chronic overlapping pain condition (96.1% vs. 58.6%), demonstrated a higher likelihood of having a mental health diagnosis (76.7% vs. 42.4%), and exhibited a greater number of comorbidities (mean ± SD: 6.0 ± 3.0 vs. 2.9 ± 2.6) compared to those not attending the pain clinic.

CONCLUSION

We found notable sociodemographic and clinical differences between these patient populations. Patients presenting with multiple comorbidities might benefit from further pain screening and referral to pain clinics to provide comprehensive care, and earlier referral could mitigate the development and progression of multimorbidities.

Comparing Anesthesia and Surgery Controlled Time for Primary Total Knee and Hip Arthroplasty Between an Academic Medical Center and a Community Hospital: Retrospective Cohort Study

BACKGROUND

Osteoarthritis is a significant cause of disability, resulting in increased joint replacement surgeries and health care costs. Establishing benchmarks that more accurately predict surgical duration could help to decrease costs, maximize efficiency, and improve patient experience. We compared the anesthesia-controlled time (ACT) and surgery-controlled time (SCT) of primary total knee (TKA) and total hip arthroplasties (THA) between an academic medical center (AMC) and a community hospital (CH) for 2 orthopedic surgeons.

OBJECTIVE

This study aims to validate and compare benchmarking times for ACT and SCT in a single patient population at both an AMC and a CH.

METHODS

This retrospective 2-center observational cohort study was conducted at the University of Colorado Hospital (AMC) and UCHealth Broomfield Hospital (CH). Cases with current procedural terminology codes for THA and TKA between January 1, 2019, and December 31, 2020, were assessed. Cases with missing data were excluded. The primary outcomes were ACT and SCT. Primary outcomes were tested for association with covariates of interest. The primary covariate of interest was the location of the procedure (CH vs AMC); secondary covariates of interest included the American Society of Anesthesiologists (ASA) classification and anesthetic type. Linear regression models were used to assess the relationships.

RESULTS

Two surgeons performed 1256 cases at the AMC and CH. A total of 10 THA cases and 12 TKA cases were excluded due to missing data. After controlling for surgeon, the ACT was greater at the AMC for THA by 3.77 minutes and for TKA by 3.58 minutes (P<.001). SCT was greater at the AMC for THA by 11.14 minutes and for TKA by 14.04 minutes (P<.001). ASA III/IV classification increased ACT for THA by 3.76 minutes (P<.001) and increased SCT for THA by 6.33 minutes after controlling for surgeon and location (P=.008). General anesthesia use was higher at the AMC for both THA (29.2% vs 7.3%) and TKA (23.8% vs 4.2%). No statistically significant association was observed between either ACT or SCT and anesthetic type (neuraxial or general) after adjusting for surgeon and location (all P>.05).

CONCLUSIONS

We observed lower ACT and SCT at the CH for both TKA and THA after controlling for the surgeon of record and ASA classification. These findings underscore the efficiency advantages of performing primary joint replacements at the CH, showcasing an average reduction of 16 minutes in SCT and 4 minutes in ACT per case. Overall, establishing more accurate benchmarks to improve the prediction of surgical duration for THA and TKA in different perioperative environments can increase the reliability of surgical duration predictions and optimize scheduling. Future studies with study populations at multiple community hospitals and academic medical centers are needed before extrapolating these findings.

Seroprevalence of Toxocara at Tra Vinh University Hospital in Vietnam

OBJECTIVE

The study aims to assess the seroprevalence of Toxocariasis and its associated risk factors among individuals attending the outpatient department at Tra Vinh University Hospital, Vietnam, in 2022.

SUBJECTS AND METHODS

A cross-sectional survey was conducted among outpatients of Tra Vinh University Hospital. Toxocariasis diagnosis was based on the Enzyme-Linked Immunosorbent Assay (ELISA) performed at the hospital's laboratory department. We assessed the seroprevalence of Toxocariasis and evaluated associated risk factors, including demographics and certain behaviors.

RESULTS

Of the 249 participants surveyed, 165 tested positive for Toxocariasis, yielding a seroprevalence of 66.3% (95% CI: 60.4-72.1). Multivariate analysis revealed that age groups up to 30 and 30-60 years had higher odds of Toxocariasis infection, with adjusted odds ratios (aOR) of 2.52 (95% CI: 1.04-6.11) and 3.21 (95% CI: 1.44-7.15) respectively. Additionally, individuals residing in rural areas and those in contact with dogs or cats had increased risks, with aORs of 2.21 (95% CI: 1.21-4.01) and 2.04 (95% CI: 1.10-3.79), respectively. Notably, hand washing before eating emerged as a protective factor against Toxocariasis, presenting an aOR of 0.38 (95% CI: 0.19-0.76).

CONCLUSIONS

Our findings underscore a significant seroprevalence (66.3%) of Toxocara spp. among outpatients at Tra Vinh University Hospital. Proactive measures, including hand hygiene before meals and after pet interactions, are advocated. There is a pronounced need for community-level epidemiological surveillance for human Toxocariasis.

Effect of concurrent mitral valve surgery for secondary mitral regurgitation upon mortality after aortic valve replacement or coronary artery bypass surgery

Objectives

It is uncertain whether concurrent mitral valve repair or replacement for moderate or greater secondary mitral regurgitation at the time of coronary artery bypass graft or aortic valve replacement surgery improves long-term survival.

Methods

Patients undergoing coronary artery bypass graft and/or aortic valve replacement surgery with moderate or greater secondary mitral regurgitation were reviewed. The effect of concurrent mitral valve repair or replacement upon long-term mortality was assessed while accounting for patient and operative characteristics and mitral regurgitation severity.

Results

Of 1,515 patients, 938 underwent coronary artery bypass graft or aortic valve replacement surgery alone and 577 underwent concurrent mitral valve repair or replacement. Concurrent mitral valve repair or replacement did not alter the risk of postoperative mortality for patients with moderate mitral regurgitation (hazard ratio = 0.93; 0.75-1.17) or more-than-moderate mitral regurgitation (hazard ratio = 1.09; 0.74-1.60) in multivariable regression. Patients with more-than-moderate mitral regurgitation undergoing coronary artery bypass graft-only surgery had a survival advantage from concurrent mitral valve repair or replacement in the first two postoperative years (P = 0.028) that did not persist beyond that time. Patients who underwent concurrent mitral valve repair or replacement had a higher rate of later mitral valve operation or reoperation over the five subsequent years (1.9% vs. 0.2%; P = 0.0014) than those who did not.

Conclusions

These observations suggest that mitral valve repair or replacement for more-than-moderate mitral regurgitation at the time of coronary artery bypass grafting may be reasonable in a suitably selected coronary artery bypass graft population but not for aortic valve replacement, with or without coronary artery bypass grafting. Our findings are supportive of 2021 European guidelines that severe secondary mitral regurgitation "should" or be "reasonabl[y]" intervened upon at the time of coronary artery bypass grafting but do not support 2020 American guidelines for performing mitral valve repair or replacement concurrent with aortic valve replacement, with or without coronary artery bypass grafting.

Tuberculin skin testing and QuantiFERON™-TB Gold Plus positivity among household contacts in Vietnam

SETTING

TB infection (TBI) is diagnosed using the technique-dependent tuberculin skin test (TST) or costly, more accurate interferon-gamma release assays. The TST (⩾10 mm) threshold was indicated by previous research among household contacts in Vietnam, but routine implementation with a different tuberculin reagent showed unexpectedly low TST positivity.

OBJECTIVE

TST (⩾5 mm and ⩾10 mm) results were compared to QuantiFERON™-TB Gold Plus (QFT) results in household contacts during community campaigns in 2020 and 2021.

DESIGN

This was a cross-sectional multi-center implementation study.

RESULTS

Among 1,330 household contacts in 2020, we found a TBI prevalence of 38.6% (QFT), similar to TST ⩾5 mm (37.4%) and higher than TST ⩾10 mm (13.1%). QFT+/TST+ was higher for TST ⩾5 mm (20.7%) than TST ⩾10 mm (9.4%). QFT was not discordant with TST ⩾5 mm (McNemar's test = 0.6, P = 0.5) but was discordant with TST ⩾10 mm (McNemar's test = 263.9, P < 0.01). Older age and Southern region increased odds for positive TST ⩾5 mm and QFT with weaker associations for TST ⩾10 mm. Agreement and discordance were similar in 2021 for 1,158 household contacts.

CONCLUSION

Tuberculin reagents affect TST positivity rates. High TB burden countries should monitor reliability of TBI diagnosis, including tuberculin potency, cold chain, and TST technique to optimize eligibility for TB preventive treatment.

Diagnostic Accuracy of Arterial Spin-Labeling, Dynamic Contrast-Enhanced, and DSC Perfusion Imaging in the Diagnosis of Recurrent High-Grade Gliomas: A Prospective Study

BACKGROUND AND PURPOSE

For patients with high-grade gliomas, the appearance of a new, enhancing lesion after surgery and chemoradiation represents a diagnostic dilemma. We hypothesized that MR perfusion without and with contrast can differentiate tumor recurrence from radiation necrosis.

MATERIALS AND METHODS

In this prospective study, we performed 3 MR perfusion methods: arterial spin-labeling, DSC, and dynamic contrast enhancement. For each lesion, we measured CBF from arterial spin-labeling, uncorrected relative CBV, and leakage-corrected relative CBV from DSC imaging. The volume transfer constant and plasma volume were obtained from dynamic contrast-enhanced imaging without and with T1 mapping using modified Look-Locker inversion recovery (MOLLI). The diagnosis of tumor recurrence or radiation necrosis was determined by either histopathology for patients who underwent re-resection or radiologic follow-up for patients who did not have re-resection.

RESULTS

There were 26 patients with 32 lesions, 19 lesions with tumor recurrence and 13 lesions with radiation necrosis. Compared with radiation necrosis, lesions with tumor recurrence had higher CBF (P = .033), leakage-corrected relative CBV (P = .048), and plasma volume using MOLLI T1 mapping (P = .012). For differentiating tumor recurrence from radiation necrosis, the areas under the curve were 0.81 for CBF, 0.80 for plasma volume using MOLLI T1 mapping, and 0.71 for leakage-corrected relative CBV. A correlation was found between CBF and leakage-corrected relative CBV (r s = 0.54), volume transfer constant, and plasma volume (0.50 < r s< 0.77) but not with uncorrected relative CBV (r s = 0.20, P = .29).

CONCLUSIONS

In the differentiation of tumor recurrence from radiation necrosis in a newly enhancing lesion, the diagnostic value of arterial spin-labeling-derived CBF is similar to that of DSC and dynamic contrast-enhancement-derived blood volume.

Virtual reality immersion compared to monitored anesthesia care for hand surgery: A randomized controlled trial

Introduction

Common anesthesia practice for hand surgery combines a preoperative regional anesthetic and intraoperative monitored anesthesia care (MAC). Despite adequate regional anesthesia, patients may receive doses of intraoperative sedatives which can result in oversedation and potentially avoidable complications. VR could prove to be a valuable tool for patients and providers by distracting the mind from processing noxious stimuli resulting in minimized sedative use and reduced risk of oversedation without negatively impacting patient satisfaction. Our hypothesis was that intraoperative VR use reduces sedative dosing during elective hand surgery without detracting from patient satisfaction as compared to a usual care control.

Methods

Forty adults undergoing hand surgery were randomized to receive either intraoperative VR in addition to MAC, or usual MAC. Patients in both groups received preoperative regional anesthesia at provider discretion. Intraoperatively, the VR group viewed programming of their choice via a head-mounted display. The primary outcome was intraoperative propofol dose per hour (mg · hr^-1). Secondary outcomes included patient reported pain and anxiety, overall satisfaction, functional outcome, and post anesthesia care unit (PACU) length of stay (LOS).

Results

Of the 40 enrolled patients, 34 completed the perioperative portion of the trial. VR group patients received significantly less propofol per hour than the control group (Mean (±SD): 125.3 (±296.0) vs 750.6 (±334.6) mg · hr^-1, p<0.001). There were no significant differences between groups in patient reported overall satisfaction, (0–100 scale, Median (IQR) 92 (77–100) vs 100 (100–100), VR vs control, p = 0.087). There were no significant differences between groups in PACU pain scores, perioperative opioid analgesic dose, or in postoperative functional outcome. PACU LOS was significantly decreased in the VR group (53.0 (43.0–72.0) vs 75.0 (57.5–89.0) min, p = 0.018).

Conclusion

VR immersion during hand surgery led to significant reductions in intraoperative propofol dose and PACU LOS without negatively impacting key patient reported outcomes.

A randomized clinical trial demonstrating cell type specific effects of hyperlipidemia and hyperinsulinemia on pituitary function

Introduction

Obesity is characterized by elevated lipids, insulin resistance and relative hypogonadotropic hypogonadism, reducing fertility and increasing risk of pregnancy complications and birth defects. We termed this phenotype ‘Reprometabolic Syndrome’ and showed that it can be recapitulated by acute infusions of lipid/insulin into healthy, normal weight, eumenorrheic women. Herein, we examined the broader impact of hyperlipidemia and euglycemic hyperinsulinemia on anterior pituitary trophic hormones and their targets.

Methods

Serum FSH, LH, TSH, growth hormone (GH), prolactin (PRL), thyroid hormones (free T4, total T3), cortisol, IGF-1, adiponectin, leptin and creatinine were measured in a secondary analysis of an interventional crossover study of 12 normal weight cycling women who underwent saline and heparin (control) infusion, or a euglycemic insulin infusion with heparin and Intralipid^® (lipid/insulin), between days 2–5 in sequential menstrual cycles.

Results

In contrast to the decrease in gonadotropins, FSH and LH, infusion of lipid/insulin had no significant effects on other trophic hormones; TSH, PRL or GH. Thyroid hormones (fT4 and total T3), cortisol, IGF-1, adiponectin and creatinine also did not differ between saline or lipid/insulin infusion conditions. Leptin increased in response to lipid/insulin (p<0.02).

Conclusion

Acute hyperlipidemia and hyperinsulinemia exerted differential, cell type specific effects on the hypothalamic-pituitary-gonadal, adrenal and thyroid axes. Elucidation of mechanisms underlying the selective modulation of pituitary trophic hormones, in response to changes in diet and metabolism, may facilitate therapeutic intervention in obesity-related neuroendocrine and reproductive dysfunction.

Joint preoperative transthoracic and intraoperative transoesophageal echocardiographic assessment of functional mitral regurgitation severity provides better association with long-term mortality

OBJECTIVES

Functional mitral regurgitation (MR) is observed with ischaemic heart disease or aortic valve disease. Assessing the value of mitral valve repair or replacement (MVR/P) is complicated by frequent discordance between preoperative transthoracic echocardiographic (pTTE) and intraoperative transoesophageal echocardiographic (iTOE) assessment of MR severity. We examined the association of pTTE and iTOE with postoperative mortality in patients with or without MR, at the time of coronary artery bypass grafting (CABG) and/or aortic valve replacement without MVR/P.

METHODS

Medical records of 6629 patients undergoing CABG and/or aortic valve replacement surgery with or without functional MR and who did not undergo MVR/P were reviewed. MR severity assessed by pTTE and iTOE were examined for association with postoperative mortality using proportional hazards regression while accounting for patient and operative characteristics.

RESULTS

In 72% of 709 patients with clinically significant (moderate or greater) functional MR detected by pTTE, iTOE performed after induction of anaesthesia demonstrated a reduction in MR severity, while 2% of patients had increased severity of MR by iTOE. iTOE assessment of MR was better associated with long-term postoperative mortality than pTTE in patients with moderate MR [hazard ratio (HR) 1.31 (1.11-1.55) vs 1.02 (0.89-1.17), P-value for comparison of HR 0.025] but was not different for more than moderate MR [1.43 (0.96-2.14) vs 1.27 (0.80-2.02)].

CONCLUSIONS

In patients undergoing CABG and/or aortic valve replacement without MVR/P, these findings support intraoperative reassessment of MR severity by iTOE as an adjunct to pTTE in the prediction of mortality. Alone, these findings do not yet provide evidence for an operative strategy.

Differential inflammatory potential of particulate matter (PM) size fractions from Imperial Valley, CA

Particulate matter (PM) in Imperial Valley originates from a variety of sources such as agriculture, traffic at the border crossing, emissions from the cross-border city of Mexicali, and the drying lakebed of the Salton Sea. Dust storms in Imperial Valley, California regularly lead to exceedances of the federal air quality standards for PM10 (diameter less than 10 microns). To determine if there are differences in the composition and biological response to Imperial County PM by size, ambient PM samples were collected from a sampling unit stationed in the northern-most part of the valley, South of the Salton Sea. Ultrafine, fine, and coarse PM samples were collected and extracted separately. Chemical composition of each size fraction was obtained after extraction by using several analytical techniques, and biological response was measured by exposing a cell line of macrophages to particles and quantifying subsequent gene expression. Biological measurements demonstrated coarse PM induced an inflammatory response in macrophages measured in increases of inflammatory markers IL-1β, IL-6, IL-8 and CXCL2 expression, whereas ultrafine and fine PM only demonstrated significant increases in expression of CYP1a1. These differential responses were due not only to particle size, but to the distinct chemical profiles of each size faction as well. Community groups in Imperial Valley have already completed several projects to learn more about local air quality, giving residents access to data that provides real-time levels of PM2.5 and PM10 as well as recommendations on health-based practices dependent on the current AQI (air quality index). However, to date there is no information on the composition or toxicity of ambient PM from the region. The data presented here could provide more definitive information on the toxicity of PM by size, and further inform the community on local air quality.

Chemoproteomics-enabled covalent ligand screen reveals a cysteine hotspot in reticulon 4 that impairs ER morphology and cancer pathogenicity

Chemical genetics has arisen as a powerful approach for identifying novel anti-cancer agents. However, a major bottleneck of this approach is identifying the targets of lead compounds that arise from screens. Here, we coupled the synthesis and screening of fragment-based cysteine-reactive covalent ligands with activity-based protein profiling (ABPP) chemoproteomic approaches to identify compounds that impair colorectal cancer pathogenicity and map the druggable hotspots targeted by these hits. Through this coupled approach, we discovered a cysteine-reactive acrylamide DKM 3-30 that significantly impaired colorectal cancer cell pathogenicity through targeting C1101 on reticulon 4 (RTN4). While little is known about the role of RTN4 in colorectal cancer, this protein has been established as a critical mediator of endoplasmic reticulum tubular network formation. We show here that covalent modification of C1101 on RTN4 by DKM 3-30 or genetic knockdown of RTN4 impairs endoplasmic reticulum and nuclear envelope morphology as well as colorectal cancer pathogenicity. We thus put forth RTN4 as a potential novel colorectal cancer therapeutic target and reveal a unique druggable hotspot within RTN4 that can be targeted by covalent ligands to impair colorectal cancer pathogenicity. Our results underscore the utility of coupling the screening of fragment-based covalent ligands with isoTOP-ABPP platforms for mining the proteome for novel druggable nodes that can be targeted for cancer therapy.

Diagnostic Accuracy of Centrally Restricted Diffusion in the Differentiation of Treatment-Related Necrosis from Tumor Recurrence in High-Grade Gliomas

BACKGROUND AND PURPOSE

Centrally restricted diffusion has been demonstrated in recurrent high-grade gliomas treated with bevacizumab. Our purpose was to assess the accuracy of centrally restricted diffusion in the diagnosis of radiation necrosis in high-grade gliomas not treated with bevacizumab.

MATERIALS AND METHODS

In this prospective study, we enrolled patients with high-grade gliomas who developed a new ring-enhancing necrotic lesion and who underwent re-resection. The presence of a centrally restricted diffusion within the ring-enhancing lesion was assessed visually on diffusion trace images and by ADC measurements on 3T preoperative diffusion tensor examination. The percentage of tumor recurrence and radiation necrosis in each surgical specimen was defined histopathologically. The association between centrally restricted diffusion and radiation necrosis was assessed using the Fisher exact test. Differences in ADC and the ADC ratio between the groups were assessed via the Mann-Whitney U test, and receiver operating characteristic curve analysis was performed.

RESULTS

Seventeen patients had re-resected ring-enhancing lesions: 8 cases of radiation necrosis and 9 cases of tumor recurrence. There was significant association between centrally restricted diffusion by visual assessment and radiation necrosis (P = .015) with a sensitivity of 75% and a specificity of 88.9%, a positive predictive value 85.7%, and a negative predictive value of 80% for the diagnosis of radiation necrosis. There was a statistically significant difference in the ADC and ADC ratio between radiation necrosis and tumor recurrence (P = .027).

CONCLUSIONS

The presence of centrally restricted diffusion in a new ring-enhancing lesion might indicate radiation necrosis rather than tumor recurrence in high-grade gliomas previously treated with standard chemoradiation without bevacizumab.

Identification of cell-type-specific mutations in nodal T-cell lymphomas

Recent genetic analysis has identified frequent mutations in ten-eleven translocation 2 (TET2), DNA methyltransferase 3A (DNMT3A), isocitrate dehydrogenase 2 (IDH2) and ras homolog family member A (RHOA) in nodal T-cell lymphomas, including angioimmunoblastic T-cell lymphoma and peripheral T-cell lymphoma, not otherwise specified. We examined the distribution of mutations in these subtypes of mature T-/natural killer cell neoplasms to determine their clonal architecture. Targeted sequencing was performed for 71 genes in tumor-derived DNA of 87 cases. The mutations were then analyzed in a programmed death-1 (PD1)-positive population enriched with tumor cells and CD20-positive B cells purified by laser microdissection from 19 cases. TET2 and DNMT3A mutations were identified in both the PD1+ cells and the CD20+ cells in 15/16 and 4/7 cases, respectively. All the RHOA and IDH2 mutations were confined to the PD1+ cells, indicating that some, including RHOA and IDH2 mutations, being specific events in tumor cells. Notably, we found that all NOTCH1 mutations were detected only in the CD20+ cells. In conclusion, we identified both B- as well as T-cell-specific mutations, and mutations common to both T and B cells. These findings indicate the expansion of a clone after multistep and multilineal acquisition of gene mutations.

Correlation of Tumor Immunohistochemistry with Dynamic Contrast-Enhanced and DSC-MRI Parameters in Patients with Gliomas

BACKGROUND AND PURPOSE

Tumor CBV is a prognostic and predictive marker for patients with gliomas. Tumor CBV can be measured noninvasively with different MR imaging techniques; however, it is not clear which of these techniques most closely reflects histologically-measured tumor CBV. Our aim was to investigate the correlations between dynamic contrast-enhanced and DSC-MR imaging parameters and immunohistochemistry in patients with gliomas.

MATERIALS AND METHODS

Forty-three patients with a new diagnosis of glioma underwent a preoperative MR imaging examination with dynamic contrast-enhanced and DSC sequences. Unnormalized and normalized cerebral blood volume was obtained from DSC MR imaging. Two sets of plasma volume and volume transfer constant maps were obtained from dynamic contrast-enhanced MR imaging. Plasma volume obtained from the phase-derived vascular input function and bookend T1 mapping (Vp_Φ) and volume transfer constant obtained from phase-derived vascular input function and bookend T1 mapping (K^trans_Φ) were determined. Plasma volume obtained from magnitude-derived vascular input function (Vp_SI) and volume transfer constant obtained from magnitude-derived vascular input function (K^trans_SI) were acquired, without T1 mapping. Using CD34 staining, we measured microvessel density and microvessel area within 3 representative areas of the resected tumor specimen. The Mann-Whitney U test was used to test for differences according to grade and degree of enhancement. The Spearman correlation was performed to determine the relationship between dynamic contrast-enhanced and DSC parameters and histopathologic measurements.

RESULTS

Microvessel area, microvessel density, dynamic contrast-enhanced, and DSC-MR imaging parameters varied according to the grade and degree of enhancement (P < .05). A strong correlation was found between microvessel area and Vp_Φ and between microvessel area and unnormalized blood volume (r_s ≥ 0.61). A moderate correlation was found between microvessel area and normalized blood volume, microvessel area and Vp_SI, microvessel area and K^trans_Φ, microvessel area and K^trans_SI, microvessel density and Vp_Φ, microvessel density and unnormalized blood volume, and microvessel density and normalized blood volume (0.44 ≤ r_s ≤ 0.57). A weaker correlation was found between microvessel density and K^trans_Φ and between microvessel density and K^trans_SI (r_s ≤ 0.41).

CONCLUSIONS

With dynamic contrast-enhanced MR imaging, use of a phase-derived vascular input function and bookend T1 mapping improves the correlation between immunohistochemistry and plasma volume, but not between immunohistochemistry and the volume transfer constant. With DSC-MR imaging, normalization of tumor CBV could decrease the correlation with microvessel area.

Redox condensation of o-halonitrobenzene with 1,2,3,4-tetrahydroisoquinoline: involvement of an unexpected auto-catalyzed redox cascade

A practical synthesis of fused benzimidazoles 5 has been developed by simply heating o-halonitrobenzenes 1 with tetrahydroisoquinolines 2. In this transformation, 2 played multiple roles as a building block, base and a double hydride donor in a cascade of uncatalyzed aromatic substitution, reduction of the nitro group, oxidation of the α-methylene group and condensation.

Organic nitrate chemistry and its implications for nitrogen budgets in an isoprene- and monoterpene-rich atmosphere: constraints from aircraft (SEAC4RS) and ground-based (SOAS) observations in the Southeast US

Formation of organic nitrates (RONO₂) during oxidation of biogenic volatile organic compounds (BVOCs: isoprene, monoterpenes) is a significant loss pathway for atmospheric nitrogen oxide radicals (NO_x), but the chemistry of RONO₂ formation and degradation remains uncertain. Here we implement a new BVOC oxidation mechanism (including updated isoprene chemistry, new monoterpene chemistry, and particle uptake of RONO₂) in the GEOS-Chem global chemical transport model with ∼25 × 25 km² resolution over North America. We evaluate the model using aircraft (SEAC⁴RS) and ground-based (SOAS) observations of NO_x, BVOCs, and RONO₂ from the Southeast US in summer 2013. The updated simulation successfully reproduces the concentrations of individual gas- and particle-phase RONO₂ species measured during the campaigns. Gas-phase isoprene nitrates account for 25-50% of observed RONO₂ in surface air, and we find that another 10% is contributed by gas-phase monoterpene nitrates. Observations in the free troposphere show an important contribution from long-lived nitrates derived from anthropogenic VOCs. During both campaigns, at least 10% of observed boundary layer RONO₂ were in the particle phase. We find that aerosol uptake followed by hydrolysis to HNO₃ accounts for 60% of simulated gas-phase RONO₂ loss in the boundary layer. Other losses are 20% by photolysis to recycle NO_x and 15% by dry deposition. RONO₂ production accounts for 20% of the net regional NO_x sink in the Southeast US in summer, limited by the spatial segregation between BVOC and NO_x emissions. This segregation implies that RONO₂ production will remain a minor sink for NO_x in the Southeast US in the future even as NO_x emissions continue to decline.

Comparison of the Diagnostic Accuracy of DSC- and Dynamic Contrast-Enhanced MRI in the Preoperative Grading of Astrocytomas

BACKGROUND AND PURPOSE

Dynamic contrast-enhanced MR imaging parameters can be biased by poor measurement of the vascular input function. We have compared the diagnostic accuracy of dynamic contrast-enhanced MR imaging by using a phase-derived vascular input function and "bookend" T1 measurements with DSC MR imaging for preoperative grading of astrocytomas.

MATERIALS AND METHODS

This prospective study included 48 patients with a new pathologic diagnosis of an astrocytoma. Preoperative MR imaging was performed at 3T, which included 2 injections of 5-mL gadobutrol for dynamic contrast-enhanced and DSC MR imaging. During dynamic contrast-enhanced MR imaging, both magnitude and phase images were acquired to estimate plasma volume obtained from phase-derived vascular input function (Vp_Φ) and volume transfer constant obtained from phase-derived vascular input function (K(trans)_Φ) as well as plasma volume obtained from magnitude-derived vascular input function (Vp_SI) and volume transfer constant obtained from magnitude-derived vascular input function (K(trans)_SI). From DSC MR imaging, corrected relative CBV was computed. Four ROIs were placed over the solid part of the tumor, and the highest value among the ROIs was recorded. A Mann-Whitney U test was used to test for difference between grades. Diagnostic accuracy was assessed by using receiver operating characteristic analysis.

RESULTS

Vp_ Φ and K(trans)_Φ values were lower for grade II compared with grade III astrocytomas (P < .05). Vp_SI and K(trans)_SI were not significantly different between grade II and grade III astrocytomas (P = .08-0.15). Relative CBV and dynamic contrast-enhanced MR imaging parameters except for K(trans)_SI were lower for grade III compared with grade IV (P ≤ .05). In differentiating low- and high-grade astrocytomas, we found no statistically significant difference in diagnostic accuracy between relative CBV and dynamic contrast-enhanced MR imaging parameters.

CONCLUSIONS

In the preoperative grading of astrocytomas, the diagnostic accuracy of dynamic contrast-enhanced MR imaging parameters is similar to that of relative CBV.

Preoperative prognostic value of dynamic contrast-enhanced MRI-derived contrast transfer coefficient and plasma volume in patients with cerebral gliomas

BACKGROUND AND PURPOSE

The prognostic value of dynamic contrast-enhanced MR imaging-derived plasma volume obtained in tumor and the contrast transfer coefficient has not been well-established in patients with gliomas. We determined whether plasma volume and contrast transfer coefficient in tumor correlated with survival in patients with gliomas in addition to other factors such as age, type of surgery, preoperative Karnofsky score, contrast enhancement, and histopathologic grade.

MATERIALS AND METHODS

This prospective study included 46 patients with a new pathologically confirmed diagnosis of glioma. The contrast transfer coefficient and plasma volume obtained in tumor maps were calculated directly from the signal-intensity curve without T1 measurements, and values were obtained from multiple small ROIs placed within tumors. Survival curve analysis was performed by dichotomizing patients into groups of high and low contrast transfer coefficient and plasma volume. Univariate analysis was performed by using dynamic contrast-enhanced parameters and clinical factors. Factors that were significant on univariate analysis were entered into multivariate analysis.

RESULTS

For all patients with gliomas, survival was worse for groups of patients with high contrast transfer coefficient and plasma volume obtained in tumor (P < .05). In subgroups of high- and low-grade gliomas, survival was worse for groups of patients with high contrast transfer coefficient and plasma volume obtained in tumor (P < .05). Univariate analysis showed that factors associated with lower survival were age older than 50 years, low Karnofsky score, biopsy-only versus resection, marked contrast enhancement versus no/mild enhancement, high contrast transfer coefficient, and high plasma volume obtained in tumor (P < .05). In multivariate analysis, a low Karnofsky score, biopsy versus resection in combination with marked contrast enhancement, and a high contrast transfer coefficient were associated with lower survival rates (P < .05).

CONCLUSIONS

In patients with glioma, those with a high contrast transfer coefficient have lower survival than those with low parameters.

Reactive uptake and photo-Fenton oxidation of glycolaldehyde in aerosol liquid water

The reactive uptake and aqueous oxidation of glycolaldehyde were examined in a photochemical flow reactor using hydrated ammonium sulfate (AS) seed aerosols at RH = 80%. The glycolaldehyde that partitioned into the aerosol liquid water was oxidized via two mechanisms that may produce aqueous OH: hydrogen peroxide photolysis (H2O2 + hν) and the photo-Fenton reaction (Fe (II) + H2O2 + hν). The uptake of 80 (±10) ppb glycolaldehyde produced 2-4 wt % organic aerosol mass in the dark (kH* = (2.09-4.17) × 10(6) M atm(-1)), and the presence of an OH source increased the aqueous uptake by a factor of 4. Although the uptake was similar in both OH-aging mechanisms, photo-Fenton significantly increased the degree of oxidation (O/C = 0.9) of the aerosols compared to H2O2 photolysis (O/C = 0.5). Aerosol organics oxidized by photo-Fenton and H2O2 photolysis resemble ambient "aged" and "fresh" OA, respectively, after the equivalent of 2 h atmospheric aging. No uptake or changes in particle composition occurred on dry seed aerosol. This work illustrates that photo-Fenton chemistry efficiently forms highly oxidized organic mass in aerosol liquid water, providing a possible mechanism to bridge the gap between bulk-phase experiments and ambient particles.

Diagnostic accuracy of dynamic contrast-enhanced MR imaging using a phase-derived vascular input function in the preoperative grading of gliomas

BACKGROUND AND PURPOSE

The accuracy of tumor plasma volume and K(trans) estimates obtained with DCE MR imaging may have inaccuracies introduced by a poor estimation of the VIF. In this study, we evaluated the diagnostic accuracy of a novel technique by using a phase-derived VIF and "bookend" T1 measurements in the preoperative grading of patients with suspected gliomas.

MATERIALS AND METHODS

This prospective study included 46 patients with a new pathologically confirmed diagnosis of glioma. Both magnitude and phase images were acquired during DCE MR imaging for estimates of K(trans)_φ and V(p_)φ (calculated from a phase-derived VIF and bookend T1 measurements) as well as K(trans)_SI and V(p_)SI (calculated from a magnitude-derived VIF without T1 measurements).

RESULTS

Median K(trans)_φ values were 0.0041 minutes(-1) (95 CI, 0.00062-0.033), 0.031 minutes(-1) (0.011-0.150), and 0.088 minutes(-1) (0.069-0.110) for grade II, III, and IV gliomas, respectively (P ≤ .05 for each). Median V(p_)φ values were 0.64 mL/100 g (0.06-1.40), 0.98 mL/100 g (0.34-2.20), and 2.16 mL/100 g (1.8-3.1) with P = .15 between grade II and III gliomas and P = .015 between grade III and IV gliomas. In differentiating low-grade from high-grade gliomas, AUCs for K(trans)_φ, V(p_φ), K(trans)_SI, and V(p_)SI were 0.87 (0.73-1), 0.84 (0.69-0.98), 0.81 (0.59-1), and 0.84 (0.66-0.91). The differences between the AUCs were not statistically significant.

CONCLUSIONS

K(trans)_φ and V(p_)φ are parameters that can help in differentiating low-grade from high-grade gliomas.

Consideration of the likely benefit from implementation of prostate image-guided radiotherapy using current margin sizes: a radiobiological analysis

OBJECTIVE

To estimate the benefit of introduction of image-guided radiotherapy (IGRT) to prostate radiotherapy practice with current clinical target volume-planning target volume (PTV) margins of 5-10 mm.

METHODS

Systematic error data collected from 50 patients were used together with a random error of σ=3.0 mm to model non-IGRT treatment. IGRT was modelled with residual errors of Σ=σ=1.5 mm. Population tumour control probability (TCP(pop)) was calculated for two three-dimensional conformal radiotherapy techniques: two-phase and concomitant boost. Treatment volumes and dose prescriptions were ostensibly the same. The relative field sizes of the treatment techniques, distribution of systematic errors and correlations between movement axes were examined.

RESULTS

The differences in TCP(pop) between the IGRT and non-IGRT regimes were 0.3% for the two-phase and 1.5% for the concomitant boost techniques. A 2-phase plan, in each phase of which the 95% isodose conformed to its respective PTV, required fields that were 3.5 mm larger than those required for the concomitant boost plan. Despite the larger field sizes, the TCP (without IGRT) in the two-phase plan was only 1.7% higher than the TCP in the concomitant boost plan. The deviation of craniocaudal systematic errors (p=0.02) from a normal distribution, and the correlation of translations in the craniocaudal and anteroposterior directions (p<0.0001) were statistically significant.

CONCLUSIONS

The expected population benefit of IGRT for the modelled situation was too small to be detected by a clinical trial of reasonable size, although there was a significant benefit to individual patients. For IGRT to have an observable population benefit, the trial would need to use smaller margins than those used in this study. Concomitant treatment techniques permit smaller fields and tighter conformality than two phases planned separately.

Running wheel exercise enhances recovery from nigrostriatal dopamine injury without inducing neuroprotection

Forced use of the forelimb contralateral to a unilateral injection of the dopaminergic neurotoxin 6-hydroxydopamine can promote recovery of motor function in that limb and can significantly decrease damage to dopamine terminals. The present study was conducted to determine (1) whether a form of voluntary exercise, wheel running, would improve motor performance in rats with such lesions, and (2) whether any beneficial effects of wheel running are attributable to ameliorating the dopaminergic damage. In experiment 1, rats were allowed to run in exercise wheels or kept in home cages for 2 1/2 weeks, then given stereotaxic infusions of 6-hydroxydopamine into the left striatum. The rats were replaced into their original environments (wheels or home cages) for four additional weeks, and asymmetries in forelimb use were quantified at 3, 10, 17, and 24 days postoperatively. After killing, dopaminergic damage was assessed by both quantifying 3 beta-(4-iodophenyl)tropan-2 beta-carboxylic acid methyl ester ([(125)I]RTI-55) binding to striatal dopamine transporters and counting tyrosine hydroxylase-positive cells in the substantia nigra. Exercised 6-hydroxydopamine-infused rats showed improved motor outcomes relative to sedentary lesioned controls, effects that were most apparent at postoperative days 17 and 24. Despite this behavioral improvement, 6-hydroxydopamine-induced loss of striatal dopamine transporters and tyrosine hydroxylase-positive nigral cells in exercised and sedentary groups did not differ. Since prior studies suggested that forced limb use improves motor performance by sparing nigrostriatal dopaminergic neurons from 6-hydroxydopamine damage, experiment 2 used a combined regimen of forced plus voluntary wheel running. Again, we found that the motor performance of exercised rats improved more rapidly than that of sedentary controls, but that there were no differences between these groups in the damage produced by 6-hydroxydopamine. It appears that voluntary exercise can facilitate recovery from partial nigrostriatal injury, but it does so without evident sparing of dopamine nerve terminals.

Hyperperfusion on perfusion computed tomography following revascularization for acute stroke

PURPOSE

To describe the findings of hyperperfusion on perfusion computed tomography (CT) in four patients following revascularization for acute stroke.

MATERIAL AND METHODS

In 2002-2003, among a series of 6 patients presenting with an acute stroke and treated with intra-arterial thrombolysis, we observed the presence of hyperperfusion in 3 patients on the follow-up CT perfusion. We included an additional patient who was treated with intravenous thrombolysis and who had hyperperfusion on the follow-up CT perfusion. We retrospectively analyzed their CT perfusion maps. Cerebral blood volume (CBV) and cerebral blood flow (CBF) maps were compared between the affected territory and the normal contralateral hemisphere.

RESULTS

In the four patients, the mean CBV and CBF were 3.6 +/- 2.0 ml/100 g and 39 +/- 25 ml/100 g/min in the affected territory compared to the normal side (mean CBV = 2.7 +/- 2.1 ml/100 g, mean CBF = 27 +/- 23 ml/100 g/min). There was no intracranial hemorrhage in the hyperperfused territories. At follow-up CT, some hyperperfused brain areas progressed to infarction, while others retained normal white to gray matter differentiation.

CONCLUSION

CT perfusion can demonstrate hyperperfusion, which can be seen in an ischemic brain territory following recanalization.

Mapping quantitative trait loci associated with leaf and stem pubescence in cotton

Leaf pubescence in cotton have a potential for insect pest management. Varying degrees of leaf trichome density in Gossypium species and cultivars have been associated to a series of five genes, referred to as t(1)-t(5). We used two segregating interspecific G. hirsutum x G. barbadense backcross populations developed in our laboratory to assess qualitatively and quantitatively leaf and stem pubescence. QTL analyses were performed using simple and composite interval mapping. Based on both types of measurements and under both types of QTL analyses, nine QTLs met permutation-based thresholds. The nine QTLs mapped to four different chromosome regions. Highest LOD values corresponded to the QTLs detected on c6 (four colocalized QTLs) and on D03 (two QTLs) for which the higher pubescence in the progeny derived from the pubescent G. hirsutum parent alleles. Conversely, on c17 (one QTL) and A01 (two QTLs), the G. hirsutum parental alleles affected negatively pubescence. These results combined with another published study confirm (1) the location in a center region of chromosome 6 of the t(1) locus as a major locus/gene determining leaf pubescence, and (2) additional genes located on seven additional chromosomes have been shown to impart trichome density either positively or negatively. The existence of a high density of PCR-based loci in most of the regions identified as harboring leaf pubescence QTLs, particularly that on chromosome 6, will facilitate future efforts for map-based cloning.

Local action of estrogen and thyroid hormone on vasoactive intestinal peptide (VIP) and galanin gene expression in the rat anterior pituitary

Neuropeptides act within the pituitary as autocrine or paracrine factors, modulating the synthesis and release of primary pituitary hormones, and possibly regulating cell proliferation and/or plasticity. Manipulation of the endocrine status of rats produces dramatic long-term changes in the pituitary expression of several peptides, including the neuropeptides galanin and vasoactive intestinal peptide (VIP). Whether or not these changes are caused indirectly by hypothalamic factors, or by hormone actions directly in the pituitary, has been only partially addressed. To determine if estrogen or thyroid hormone can act directly within the pituitary to regulate VIP and galanin gene expression, cultured female rat pituitary cells were treated with 10 nM 1,17 beta-estradiol (E2) or triiodothyronine (T(3)). E2 treatment for three days resulted in an approximate 5-fold and 7-fold increase in VIP and galanin mRNA, respectively. In contrast, T(3) treatment reduced the mRNA levels of these neuropeptides to approximately 40% and 30% of control values. A time course study indicated that the actions of estrogen on VIP and galanin mRNA, and of thyroid hormone on VIP mRNA were readily apparent after 24h. The rat pituitary tumor cell line RC-4B/C was found to express easily detectable levels of galanin but not VIP mRNA. Galanin gene expression in these cells was moderately increased by E2 and decreased by T(3). Transfection of a series of luciferase plasmids containing 5 kb to 131 bp of the bovine galanin promoter fused to luciferase revealed cell-type specific enhancer sequences located between -452 and -131 bp of the galanin gene transcription start site. However, transfected plasmids were minimally responsive to E2 and T(3) treatment. Overall the results suggest that E2 and T(3) exert significant local actions in the pituitary on VIP and galanin gene expression. The bovine galanin gene fragment used in these studies contains a potential pituitary cell-type specific enhancer, but appears to lack strong E2-and T(3)-responsive sequences.

The effect of sewage sludge composting on the quantitative state of some groups of bacteria and fungi

Analysis of the quantitative state of disease causing bacteria and of other microbic groups were done on the sewage sludge from a sewage treatment plant. The results of the analysis include the ammonifying bacteria, nitrifying and denitrifying bacteria. The general quantity of bacteria and fungi in a secondary dehydrated sludge, fermented secondary dehydrated sludge, and in composted secondary dehydrated sludge was deterinated. Composts were prepared from dehydrated secondary sludge with the addition of sawdust. Microbiological analysis of sewage sludge showed, that the quantities of the fecal coli bacteria were 6500; 220 and 150 cells per cm3 of the secondary dehydrated sludge, fermented secondary dehydrated sludge and composted dehydrated secondary sludge, respectively. The numbers of Salmonella were respectively 67.80; 6.48 and 6.60 cells per cm3. The general numbers of bacteria were 2.98 x 10(7); 2.79 x 10(7); 2.15 x 10(7) cells per cm3 of sludge. The cell numbers of fungi were: 6.20x 10(2); 19.60 x 10(2); 7.80 x 10(2) per cm3 of sludge. In the three types of sludge, the results show great numbers of the ammonifying, nitrifying and denitrifying bacteria. Of the analysed groups of bacteria, the highest numbers of cells were found for general bacteria; ammonifying and nitrifying bacteria were next in abundance; still fewer were the denitrifying bacteria. Fungi and pathogenic bacteria were the least numerous.

Pharmaceutical sector in transition--a cross sectional study in Vietnam

Increasing efforts are being made to improve pharmaceutical sector performance in low- and middle-income countries. An essential tool for such work is an objective and standard method of assessment which can be used to promote evidenced based National Drug Policy development and implementation. The average drug expenditure per capita has steadily increased in Vietnam and at the time of this study a National Drug Policy was being developed. This study assessed the Vietnamese pharmaceutical sector 1991-1994, focusing on the standard of the drug quality control system, availability of drugs and rational use of essential drugs in the private and public sectors by means of standardised indicators. The results from this study show that the quality control system is impaired and does not have capacity to quality control all drugs on the market. The availability of essential drugs is good whereas essential drugs are poorly prescribed, injections common and there is a high average number of drugs per prescription, both in the public and private sectors. Violations are common and enforcement of regulations weak. On top of this there is an active commercial advertising and marketing of drugs. These findings identify priorities for action to improve the present situation where the development and implementation of the Vietnamese National Drug Policy will be of major importance.

Regulation of the diabetes-associated autoantigen IA-2 in INS-1 pancreatic beta-cells

IA-2, a member of the protein tyrosine phosphatase family, represents a major target autoantigen in type 1 diabetes. To study the regulation of IA-2 gene expression, we used INS-1 insulinoma cells to analyze beta-cell signal transduction pathways as well as the effect of metabolic and hormonal factors involved in the regulation of the insulin secretory pathway. Quantitative competitive reverse transcriptase-polymerase chain reaction revealed that an increase of cellular cAMP mediated by forskolin (10 micromol/l, 24 h) or 3-isobutyl-1-methylxanthine (100 micromol/l, 24 h) induced maximal stimulation of IA-2 mRNA levels (451 +/- 85 and 338 +/- 86% compared with basal conditions; P < 0.001). In contrast, activation of protein kinase C (PKC) by short-term treatment with phorbol 12-myristate 13-acetate (PMA) (1 micromol/l, 6 h) did not alter IA-2 expression, whereas depletion of PKC by prolonged culturing (24 h) exerted a significant inhibition (57 +/- 24%; P < 0.05). cAMP-dependent upregulation was confirmed by the findings that glucagon (10 micromol/l, 24-48 h) increased levels of IA-2 mRNA (190 +/- 35%; P < 0.05), whereas short-term incubation with high glucose concentration showed no effect. However, prolonged incubation in high glucose (21 mmol/l) induced a time- and dose-dependent increase of IA-2 mRNA expression, reaching maximal values after 144 h (285 +/- 68%; P < 0.05). These studies demonstrate that stimuli of insulin secretion that operate by activation of adenylate cyclase generating cAMP significantly increase IA-2 gene expression. In contrast, activation of PKC by high glucose concentration or PMA exerted no effect, suggesting that IA-2 gene expression is not simply coupled to insulin secretion, but may be involved in the fine regulation of beta-cell function. These findings may be important to clarify the function of IA-2 in beta-cells and elucidate mechanisms involved in the induction of autoimmunity to IA-2.

Identification of a nucleic acid binding domain in eukaryotic initiation factor eIFiso4G from wheat

Higher plants have two complexes that bind the m7G-cap structure of mRNA and mediate interactions between mRNA and ribosomal subunits, designated eIF4F and eIFiso4F. Both complexes contain a small subunit that binds the 5'-cap structure of mRNA, and a large subunit, eIF4G or eIFiso4G, that binds other translation factors and RNA. Sequence-specific proteases were used to cleave native cap-binding complexes into structural domains, which were purified by affinity chromatography. We show here that eIFiso4G contains a central protease-resistant domain that binds specifically to nucleic acids. This domain spans Gln170 to Glu443 and includes four of the six homology blocks shared by eIFiso4G and eIF4G. A slightly shorter overlapping sequence, from Gly202 to Lys445, had no nucleic acid binding activity, indicating that the N-terminal end of the nucleic acid binding site lies within Gln170 to Arg201. The binding of the central domain and native eIFiso4F to RNA homopolymers and double- and single-stranded DNAs was studied. Both molecules had highest affinity for poly(G) and recognized single- and double-stranded sequences.

Synthesis of 1-[11C]methylpiperidin-4-yl propionate ([11C]PMP) for in vivo measurements of acetylcholinesterase activity

Synthesis of 1-[11C]methylpiperidin-4-yl propionate ([11C]PMP), an in vivo substrate for acetylcholinesterase, is reported. An improved preparation of 4-piperidinyl propionate (PHP), the immediate precursor for radiolabeling, was accomplished in three steps from 4-hydroxypiperidine by (a) protection of the amine as the benzyl carbamate, (b) acylation with propionyl chloride, and (c) deprotection of the carbamate by catalytic hydrogenation. The final product was obtained in an overall 82% yield. Reaction of the free base form of PHP with [11C]methyl trifluoromethanesulfonate at room temperature in N,N-dimethylformamide, followed by high performance liquid chromatography (HPLC) purification, provided [11C]PMP in 57% radiochemical yield, > 99% radiochemical purity, and > 1500 Ci/mmol at the end of synthesis. The total synthesis time from end-of-bombardment was 35 min. [11C]PMP can thus be reliably prepared for routine clinical studies of acetylcholinesterase in human brain using positron emission tomography.

Syntheses of carbon-11 labeled piperidine esters as potential in vivo substrates for acetylcholinesterase

A series of carbon-11 labeled N-methylpiperidinyl esters were prepared as potential in vivo substrates for acetylcholinesterase (AChE). Target compounds were designed based on the structure of N-[11C]methylpiperidin-4-yl propionate, an ester currently used to measure AChE enzymatic activity in the human brain, to examine the structure-activity relationship for in vivo enzymatic hydrolysis. Changes in steric bulk and in the ester order ("reverse" esters) were made. Addition of methyl groups was made to both the acid side chain (synthesis of N-[11C]methylmethylpiperidin-4-yl isobutyrate) and to the piperidine ring (syntheses of N-[11C]methyl-4-methylpiperidin-4-yl propionate, N-[11C]methyl-4-methylpiperidin-4-yl acetate, and N-[11C]methyl-3-methylpiperidin-4-yl propionate). Alterations of the order of the ester heteroatoms was accomplished through syntheses of the N-[11C]methyl-2,3- and 4-piperidinecarboxylic acid ethyl esters. Finally, an additional piperidine-based ester (N-[11C]methylpiperidin-2-yl)methyl propionate was also prepared. All carbon-11-labeled esters were prepared by N-[11C]methylation reactions, using the desmethyl precursors and no-carrier-added [11C]methyltriflate, and were obtained in decay-corrected yields (not optimized) of 10-40% and high specific activities.

N-[11C]methylpiperidine esters as acetylcholinesterase substrates: an in vivo structure-reactivity study

A series of simple esters incorporating the N-[11C]methylpiperidine structure were examined as in vivo substrates for acetylcholinesterase in mouse brain. 4-N-[11C]Methylpiperidinyl esters, including the acetate, propionate and isobutyrate esters, are good in vivo substrates for mammalian cholinesterases. Introduction of a methyl group at the 4-position of the 4-piperidinol esters, to form the ester of a teritary alcohol, effectively blocks enzymatic action. Methylation of 4-N-[11C]methylpiperidinyl propionate at the 3-position gives a derivative with increased in vivo reactivity toward acetylcholinesterase. Esters of piperidinecarboxylic acids (nipecotic, isonipecotic and pipecolinic acid ethyl esters) are not hydrolyzed by acetylcholinesterase in vivo, nor do they act as in vivo inhibitors of the enzyme. This study has identified simple methods to both increase and decrease the in vivo reactivity of piperidinyl esters toward acetylcholinesterase.

Neural tube expression of pituitary adenylate cyclase-activating peptide (PACAP) and receptor: potential role in patterning and neurogenesis

Neural tube patterning in vertebrates is controlled in part by locally secreted factors that act in a paracrine manner on nearby cells to regulate proliferation and gene expression. We show here by in situ hybridization that genes for the neuropeptide pituitary adenylate cyclase-activating peptide (PACAP) and one of its high-affinity receptors (PAC1) are widely expressed in the mouse neural tube on embryonic day (E) 10.5. Transcripts for the ligand are present in differentiating neurons in much of the neural tube, whereas the receptor gene is expressed in the underlying ventricular zone, most prominently in the alar region and floor plate. PACAP potently increased cAMP levels more than 20-fold in cultured E10.5 hindbrain neuroepithelial cells, suggesting that PACAP activates protein kinase A (PKA) in the neural tube and might act in the process of patterning. Consistent with this possibility, PACAP down-regulated expression of the sonic hedgehog- and PKA-dependent target gene gli-1 in cultured neuroepithelial cells, concomitant with a decrease in DNA synthesis. PACAP is thus an early inducer of cAMP levels in the embryo and may act in the neural tube during patterning to control cell proliferation and gene expression.

Purification and characterization of a dextranase from Sporothrix schenckii

A dextranase (EC 3.2.1.11) was purified and characterized from the IP-29 strain of Sporothrix schenckii, a dimorphic pathogenic fungus. Growing cells secreted the enzyme into a standard culture medium (20 degrees C) that supports the mycelial phase. Soluble bacterial dextrans substituted for glucose as substrate with a small decrease in cellular yield but a tenfold increase in the production of dextranase. This enzyme is a monomeric protein with a molecular mass of 79 kDa, a pH optimum of 5.0, and an action pattern against a soluble 170-kDa bacterial dextran that leads to a final mixture of glucose (38%), isomaltose (38%), and branched oligosaccharides (24%). In the presence of 200 mM sodium acetate buffer (pH 5.0), the Km for soluble dextran was 0.067 +/- 0.003% (w/v). Salts of Hg2+, (UO2)2+, Pb2+, Cu2+, and Zn2+ inhibited by affecting both Vmax and Km. The enzyme was most stable between pH values of 4.50 and 4.75, where the half-life at 55 degrees C was 18 min and the energy of activation for heat denaturation was 99 kcal/mol. S. schenckii dextranase catalyzed the degradation of cross-linked dextran chains in Sephadex G-50 to G-200, and the latter was a good substrate for cell growth at 20 degrees C. Highly cross-linked grades (i.e., G-10 and G-25) were refractory to hydrolysis. Most strains of S. schenckii from Europe and North America tested positive for dextranase when grown at 20 degrees C. All of these isolates grew on glucose at 35 degrees C, a condition that is typically associated with the yeast phase, but they did not express dextranase and were incapable of using dextran as a carbon source at the higher temperature.