Does a Custom Electronic Health Record Alert System Improve Physician Compliance With National Quality Measures for Palliative Bone Metastasis Radiotherapy?

PURPOSE

In an effort to promote cost-conscious, high-quality, and patient-centered care in the palliative radiation of painful bone metastases, the National Quality Forum (NQF) formed measure 1822 in 2012, which recommends the use of one of the four dose-fractionation schemes (30 Gy in 10 fractions, 24 Gy in 6 fractions, 20 Gy in 5 fractions, or 8 Gy in a single fraction). We investigated whether a custom electronic health record (EHR) alert system improved quality measure compliance among 88 physicians at a large academic center and institutional network.

METHODS

In March 2018, a multiphase alert system was embedded in a custom web-based EHR. Prior to a course of palliative bone radiation, the alert system notified the user of NQF 1822 recommendations and, once prescription was completed, either affirmed compliance or advised a change in treatment schedule. Rates of compliance were evaluated before and after implementation of alert system.

RESULTS

Of 2,399 treatment courses, 86.5% were compliant with NQF 1822 recommendations. There was no difference in rates of NQF 1822 compliance before or after implementation of the custom EHR alert (86.0% before March 2018 v 86.9% during and after March 2018, P = .551).

CONCLUSION

There was no change in rates of compliance following implementation of a custom EHR alert system designed to make treatment recommendations based on national quality measure guidelines. To be of most benefit, future palliative bone metastasis decision aids should leverage peer review, target a clear practice deficiency, center upon high-quality practice guidelines, and allow flexibility to reflect the diversity of clinical scenarios.

National Quality Measure Compliance for Palliative Bone Radiation Among Patients With Metastatic Non-Small Cell Lung Cancer

BACKGROUND

There exists wide practice variability in palliative treatment schedules for bone metastases. In an effort to reduce variation and promote high-quality, cost-conscious care, the National Quality Forum (NQF) endorsed measure 1822 in 2012. This measure recommends the use of 30 Gy in 10 fractions, 24 Gy in 6 fractions, 20 Gy in 5 fractions, or 8 Gy in a single fraction for palliative radiation for bone metastases. We report on longitudinal compliance with this measure.

METHODS

Using the National Cancer Database, patients with metastatic thoracic non-small cell lung cancer diagnosed between 2004 and 2016 who received radiation therapy for bony sites of metastatic disease were identified. Treatment courses fitting 1 of the 4 recommended schedules under NQF 1822 were coded as compliant. Rates of compliance by patient, tumor, and treatment characteristics were analyzed.

RESULTS

A total of 42,685 patients met the criteria for inclusion. Among all patients, 60.2% of treatment courses were compliant according to NQF 1822. Compliance increased over time and was highest for treatments to the extremity (69.8%), lowest for treatments to the skull or head (48.8%), and higher for academic practice (67.1%) compared with community (56.0%) or integrated network facilities (61.2%). On multivariable analysis, predictors of NQF 1822 compliance included year of diagnosis after 2011, treatment to an extremity, or treatment at an academic facility. Of noncompliant treatment courses, extended fractionation (≥11 fractions) occurred in 62.6% and was more common before 2012, in community practice, and for treatments of the skull or head.

CONCLUSIONS

Among patients treated for metastatic non-small cell lung cancer, compliance with NQF 1822 increased over time. Although extended fractionation constituted a majority of noncompliant treatment courses, a substantial proportion also involved shorter courses.

A Dosimetric Comparison of Oral Cavity Sparing in the Unilateral Treatment of Early Stage Tonsil Cancer: IMRT, IMPT, and Tongue-Deviating Oral Stents

Introduction

Tongue-deviating oral stents (TDOS) are commonly used during unilateral neck radiation therapy to reduce unnecessary dose to nontarget oral structures. Their benefit in the setting of highly conformal treatment techniques, however, is not defined. The goal of this study was to investigate the potential benefit of TDOS use on dosimetric parameters in unilateral intensity modulated radiation therapy (IMRT) and intensity modulated proton therapy (IMPT).

Methods

A total of 16 patients with T1-2 tonsil cancer treated at a single institution were selected, of which 8 were simulated/treated with a TDOS and 8 without a TDOS. All received definitive unilateral IMRT to a dose of 66 Gy in 30 fx. IMPT plans were generated for each patient for study purposes and optimized according to standard institutional practice.

Results

For IMRT plans, the presence of a TDOS (vs without) was associated with a significantly lower oral mucosa mean dose (31.4 vs 35.3 Gy; P = .020) and V30 (42.7% vs 57.1%; P = .025). For IMPT plans, the presence of TDOS (vs without) was not associated with any improvement in oral mucosa mean dose (18.3 vs 19.9 Gy; P = .274) or V30 (25.0% vs 26.2%; P = .655). IMPT plans without TDOS compared with IMRT plans with TDOS demonstrated reduced oral mucosa mean dose (P < .001) and V30 (P < .001).

Conclusion

The use of a TDOS for the unilateral treatment of well-lateralized tonsil cancers was associated with oral mucosa sparing for IMRT, but not for IMPT. Moreover, mucosa sparing was improved for IMPT plans without a TDOS compared to IMRT plans with a TDOS.

Racial and Ethnic Disparities Among Participants in US-Based Phase 3 Randomized Cancer Clinical Trials

Although improving representation of racial and ethnic groups in United States clinical trials has been a focus of federal initiatives for nearly 3 decades, the status of racial and ethnic minority enrollment on cancer trials is largely unknown. We used a broad collection of phase 3 cancer trials derived from ClinicalTrials.gov to evaluate racial and ethnic enrollment among US cancer trials. The difference in incidence by race and ethnicity was the median absolute difference between trial and corresponding Surveillance, Epidemiology, and End Results data. All statistical tests were 2-sided. Using a cohort of 168 eligible trials, median difference in incidence by race and ethnicity was +6.8% for Whites (interquartile range [IQR] = +1.8% to +10.1%; P < .001 by Wilcoxon signed-rank test comparing median difference in incidence by race and ethnicity to a value of 0), -2.6% for Blacks (IQR = -5.1% to +1.2%; P = .004), -4.7% for Hispanics (IQR = -7.5% to -0.3%; P < .001), and -4.7% for Asians (IQR = -5.7% to -3.3%; P < .001). These data demonstrate overrepresentation of Whites, with continued underrepresentation of racial and ethnic minority subgroups.

Prospective longitudinal patient-reported outcomes of swallowing following intensity modulated proton therapy for oropharyngeal cancer

BACKGROUND AND PURPOSE

With an enlarging population of long-term oropharyngeal cancer survivors, dysphagia is an increasingly important toxicity following oropharynx cancer treatment. While lower doses to normal surrounding structures may be achieved with intensity modulated proton therapy (IMPT) compared to photon-based radiation, the clinical benefit is uncertain.

METHODS AND MATERIALS

Seventy-one patients with stage III/IV oropharyngeal cancer (AJCC 7th edition) undergoing definitive IMPT on a longitudinal prospective cohort study who had completed the MD Anderson Dysphagia Inventory (MDADI) at pre-specified time points were included.

RESULTS

The majority of patients had HPV-positive tumors (85.9%) and received bilateral neck radiation (81.4%) with concurrent systemic therapy (61.8%). Mean composite MDADI scores decreased from 88.2 at baseline to 59.6 at treatment week 6, and then increased to 74.4 by follow up week 10, 77.0 by 6 months follow up, 80.5 by 12 months follow up, and 80.1 by 24 months follow up. At baseline, only 5.6% of patients recording a poor composite score (lower than 60), compared to 61.2% at treatment week 6, 19.1% at follow up week 10, 13.0% at 6 months follow up, 13.5% at 1 year follow up, and 11.1% at 2 years follow up.

CONCLUSIONS

Patient reported outcomes following IMPT for oropharyngeal cancer demonstrates decreased swallowing function at completion of treatment with relatively rapid recovery by 10 weeks follow up and steady improvement through 2 years. The results are comparable to similar longitudinal studies of photon-based radiotherapy for oropharynx cancer, and suggest that IMPT confers no additional excess toxicity related to swallowing.

Stereotactic Body Radiation Therapy for the Definitive Treatment of Early Stage Kidney Cancer: A Survival Comparison With Surgery, Tumor Ablation, and Observation

Purpose

Partial nephrectomy is the preferred definitive treatment for early stage kidney cancer, with tumor ablative techniques or active surveillance reserved for patients not undergoing surgery. Stereotactic body radiation therapy (SBRT) has emerged as a potential noninvasive alternative for patients with early stage kidney cancer not amenable to surgery, with early reports suggesting excellent rates of local control and limited toxicity.

Methods and Materials

The national cancer database from 2004 to 2014 was queried for patients who received a diagnosis of T1N0M0 kidney cancer. Treatments were categorized as surgery (partial or total nephrectomy), tumor ablation (cryoablation or thermal ablation), SBRT (radiation therapy in 5 fractions or less to a total biological effective dose [BED₁₀] of 72 or more), or observation. A propensity score was generated by multinomial logistic regression. A Cox proportional hazards model was fit to determine association between overall survival and treatment group with propensity score adjustments for patient, demographic, and treatment characteristics.

Results

A total of 165,298 received surgery, 17,196 underwent tumor ablation, 104 underwent SBRT, and 18,241 were observed. Median follow-up was 51 months. On multivariable analysis, surgery, tumor ablation, and SBRT were associated with a decreased risk of death compared with observation, with hazard ratios of 0.25 (95% confidence interval, 0.24-0.26, P < .001), 0.36 (0.35-0.38, P < .001), and 0.56 (0.39-0.79, P < .001), respectively. When stratifying by BED₁₀ and compared with observation, hazard ratio for risk of death for patients treated with SBRT to a BED₁₀ ≥100 (n = 62) and a BED₁₀ <100 (n = 42) was 0.34 (0.19-0.60, P < .001) and 0.90 (0.58-1.4, P = .64), respectively.

Conclusions

In this population-based cohort, patients undergoing high-dose SBRT (BED₁₀ ≥100) for early stage kidney cancer demonstrated longer survival compared with patients undergoing observation. This may be a promising noninvasive treatment option for nonsurgical candidates with prospective efficacy and safety assessments meriting study in future clinical trials.

Seed, soil, and spine stereotactic radiosurgery: A unique case of metastatic dissemination

A 52 year-old gentleman with metastatic pheochromocytoma received single fraction spine stereotactic radiosurgery (SSRS) to an isolated L3 metastasis. Two years later, he developed widespread osseous metastatic disease involving nearly every vertebral body level with the striking exception of the treated L3 vertebrae. The "seed and soil" hypothesis of metastatic dissemination was developed over a century ago and states that tumors cells (the "seed") preferentially grow in select host tissue microenvironments (the "soil"). The high-dose radiation delivered by SSRS may have altered the microenvironment "soil" of the treated L3 vertebrae, rendering it inhospitable to the growth of future metastases. With emerging evidence in support of high-dose stereotactic radiation for oligometastatic disease, there will likely be increasing opportunity to observe and understand treatment changes in the tissue microenvironment and how it relates to the potential for metastatic seeding.

Dose Escalation for Prostate Adenocarcinoma: A Long-Term Update on the Outcomes of a Phase 3, Single Institution Randomized Clinical Trial

PURPOSE

To determine the long-term outcomes for prostate adenocarcinoma when escalating radiation dose from 70 Gy to 78 Gy.

METHODS AND MATERIALS

Between 1993 and 1998, 301 patients with biopsy-proven clinical stage T1b-T3 prostate adenocarcinoma, any prostate-specific antigen level, and any Gleason score were randomized to 70 Gy in 35 fractions versus 78 Gy in 39 fractions of photon radiation therapy using a 4-field box technique without hormone deprivation therapy. The primary outcome was powered to detect a 15% difference in biochemical or clinical failure. Secondary outcomes included survival, prostate cancer mortality, biochemical failure, local failure, nodal failure, distant failure, and secondary malignancy rates.

RESULTS

With a median follow-up of 14.3 years, the cumulative incidence of 15-year biochemical or clinical failure was 18.9% versus 12.0% in the 70 Gy versus 78 Gy arms, respectively (subhazard ratio [sHR], 0.61; 95% confidence interval [CI], 0.38-0.98; Fine-Gray P = .042). The 15-year cumulative incidence of distant metastasis was 3.4% versus 1.1%, respectively (sHR, 0.33; 95% CI, 0.13-0.82; Fine-Gray P = .018). The 15-year cumulative incidence of prostate cancer-specific mortality was 6.2% versus 3.2%, respectively, (sHR, 0.52; 95% CI, 0.27-0.98; Fine-Gray P = .045). There were no differences in overall survival (HR, 1.10; 95% CI, 0.84-1.45; log rank P = .469) or other-cause survival (sHR, 1.33; 95% CI, 0.99-1.79; Fine-Gray P = .061). Salvage therapy was more common in the 70 Gy arm, at 38.7% versus 21.9% in the 78 Gy arm (P = .002). There was a 2.3% secondary solid malignancy rate (1 bladder, 6 rectal) within the radiation treatment field, which was not significantly different between treatment arms.

CONCLUSIONS

Dose escalation by 8 Gy (78 Gy vs 70 Gy) provided a sustained improvement in biochemical and clinical failure, which translated into lower salvage rates and improved prostate cancer-specific mortality, but not overall survival. Long-term follow-up demonstrated a low incidence of potential solid tumor secondary malignancies.

Provider variability in intensity modulated radiation therapy utilization among Medicare beneficiaries in the United States

BACKGROUND

In this study, we sought to examine the variation in intensity modulated radiation therapy (IMRT) use among radiation oncology providers.

METHODS AND MATERIALS

The Medicare Physician and Other Supplier Public Use File was queried for radiation oncologists practicing during 2014. Healthcare Common Procedural Coding System code 77301 was designated as IMRT planning with metrics including number of total IMRT plans, rate of IMRT utilization, and number of IMRT plans per distinct beneficiary.

RESULTS

Of 2759 radiation oncologists, the median number of total IMRT plans was 26 (mean, 33.4; standard deviation, 26.2; range, 11-321) with a median IMRT utilization rate of 36% (mean, 43%; standard deviation, 25%; range, 4% to 100%) and a median number of IMRT plans per beneficiary of 1.02 (mean, 1.07; range, 1.00-3.73). On multivariable analysis, increased IMRT utilization was associated with male sex, academic practice, technical fee billing, freestanding practice, practice in a county with 21 or more radiation oncologists, and practice in the southern United States (P < .05). The top 1% of users (28 providers) billed a mean 181 IMRT plans with an IMRT utilization rate of 66% and 1.52 IMRT plans per beneficiary. Of these 28 providers, 24 had billed technical fees, 25 practiced in freestanding clinics, and 20 practiced in the South.

CONCLUSIONS

Technical fee billing, freestanding practice, male sex, and location in the South were associated with increased IMRT use. A small group of outliers shared several common demographic and practice-based characteristics.

Insurance Status and Racial Disparities in Cancer-Specific Mortality in the United States: A Population-Based Analysis

Background: Cancer-specific mortality (CSM) is known to be higher among blacks and lower among Hispanics compared with whites. Private insurance confers CSM benefit, but few studies have examined the relationship between insurance status and racial disparities. We sought to determine differences in CSM between races within insurance subgroups.Methods: A population-based cohort of 577,716 patients age 18 to 64 years diagnosed with one of the 10 solid malignancies causing the greatest mortality over 2007 to 2012 were obtained from Surveillance, Epidemiology, and End Results. A Cox proportional hazards model for CSM was constructed to adjust for known prognostic factors, and interaction analysis between race and insurance was performed to generate stratum-specific HRs.Results: Blacks had similar CSM to whites among the uninsured [HR = 1.01; 95% confidence interval (CI), 0.96-1.05], but higher CSM among the Medicaid (HR = 1.04; 95% CI, 0.01-1.07) and non-Medicaid (HR = 1.14; 95% CI, 1.12-1.16) strata. Hispanics had lower CSM compared with whites among uninsured (HR = 0.80; 95% CI, 0.76-0.85) and Medicaid (HR = 0.88; 95% CI, 0.85-0.91) patients, but there was no difference among non-Medicaid patients (HR = 0.99; 95% CI, 0.97-1.01). Asians had lower CSM compared with whites among all insurance types: uninsured (HR = 0.80; 95% CI, 0.76-0.85), Medicaid (HR = 0.81; 95% CI, 0.77-0.85), and non-Medicaid (HR = 0.85; 95% CI, 0.83-0.87).Conclusions: The disparity between blacks and whites was largest, and the advantage of Hispanic race was absent within the non-Medicaid subgroup.Impact: These findings suggest that whites derive greater benefit from private insurance than blacks and Hispanics. Further research is necessary to determine why this differential exists and how disparities can be improved. Cancer Epidemiol Biomarkers Prev; 26(6); 869-75. ©2017 AACR.

A brighter future? The impact of insurance and socioeconomic status on cancer outcomes in the USA: a review

Uninsured and Medicaid-insured cancer patients have been shown to present with more advanced disease, less often receive cancer-directed therapy and suffer higher rates of mortality than those with private insurance. The Patient Protection and Affordable Care Act was signed into law in March of 2010 and seeks to increase rates of public and private health insurance. Although several provisions will in particular benefit those with chronic and high-cost medical conditions such as cancer, the extent to which disparities in cancer care will be eliminated is uncertain. Further legislative changes may be needed to ensure equal and adequate cancer care for all patients regardless of insurance or socioeconomic status.

Proton versus conventional radiotherapy for pediatric salivary gland tumors: Acute toxicity and dosimetric characteristics

PURPOSE

We evaluated acute toxicity profiles and dosimetric data for children with salivary gland tumors treated with adjuvant photon/electron-based radiation therapy (X/E RT) or proton therapy (PRT).

METHODS AND MATERIALS

We identified 24 patients who had received adjuvant radiotherapy for salivary gland tumors. Data were extracted from the medical records and the treatment planning systems. Toxicity was scored according to the Common Terminology Criteria for Adverse Effects 4.0.

RESULTS

Eleven patients received X/E RT and 13 PRT, with a median prescribed dose of 60 Gy in each group. In the X/E RT group, 54% of patients developed acute grade II/III dermatitis, 27% grade II/III dysphagia, and 91% grade II/III mucositis, and the median weight loss was 5.3% with one patient requiring feeding tube placement. In the PRT group, 53% had acute grade II/III dermatitis, 0% grade II/III dysphagia, and 46% grade II/III mucositis, with a median weight gain of 1.2%. Additionally, PRT was associated with lower mean doses to several normal surrounding midline and contralateral structures.

CONCLUSION

In this retrospective study of pediatric salivary tumors, PRT was associated with a favorable acute toxicity and dosimetric profile. Continued follow-up is needed to identify long-term toxicity and survival data.

Variation in insurance status by patient demographics and tumor site among nonelderly adult patients with cancer

BACKGROUND

In the United States, an estimated 48 million individuals live without health insurance. The purpose of the current study was to explore the Variation in insurance status by patient demographics and tumor site among nonelderly adult patients with cancer.

METHODS

A total of 688,794 patients aged 18 to 64 years who were diagnosed with one of the top 25 incident cancers (representing 95% of all cancer diagnoses) between 2007 and 2010 in the Surveillance, Epidemiology, and End Results (SEER) database were analyzed. Patient characteristics included age, race, sex, marital status, and rural or urban residence. County-level demographics included percent poverty level. Insurance status was defined as having non-Medicaid insurance, Medicaid coverage, or no insurance.

RESULTS

On multivariate logistic regression analyses, younger age, male sex, nonwhite race, being unmarried, residence in counties with higher levels of poverty, and rural residence were associated with being uninsured versus having non-Medicaid insurance (all P <.001). The highest rates of non-Medicaid insurance were noted among patients with prostate cancer (92.3%), melanoma of the skin (92.5%), and thyroid cancer (89.5%), whereas the lowest rates of non-Medicaid insurance were observed among patients with cervical cancer (64.2%), liver cancer (67.9%), and stomach cancer (70.9%) (P <.001). Among uninsured individuals, the most prevalent cancers were lung cancer (14.9%), colorectal cancer (12.1%), and breast cancer (10.2%) (P <.001). Lung cancer caused the majority of cancer mortality in all insurance groups.

CONCLUSIONS

Rates of insurance coverage vary greatly by demographics and by cancer type. The expansion of health insurance coverage would be expected to disproportionally benefit certain demographic populations and cancer types.

PKN Activation via Transforming Growth Factor-β1 (TGF-β1) Receptor Signaling Delays G2/M Phase Transition in Vascular Smooth Muscle Cells

The transition of vascular smooth muscle cells (VSMCs) from G2 phase into the M (mitosis) phase of the cell cycle is a tightly controlled process. As an arterial SMC prepares for a G2/M transition, the cell has primed the Cdc2/cyclinB1 complex for activation by the phosphorylation of threonine-161 residue on Cdc2. This phosphorylation is necessary but not sufficient for the VSMC to enter into the M phase. In order to enter into mitosis, a phosphatase, Cdc25C, must first dephosphorylate two other critical residues: tyrosine-15 and threonine-14. If Cdc25C phosphatase activity is blocked, VSMC entry into mitosis is delayed. However, how the activity of Cdc25C is regulated has not been fully illustrated. In an earlier published study we have demonstrated that exposure of the VSMC line, PAC-1, to Transforming growth factor-beta1 (TGF-beta1), activated PKN (a RhoA-dependent kinase). Here we show that exposure to TGF-beta1 delays the G2/M transition by 2 hrs in G1/S synchronized and released PAC-1 culture. This delay is abolished by the RhoA kinase inhibitors, HA1077 or Y-27632. More importantly, RNAi knockdown of PKN expression prevents the G2/M transition delay induced by TGF-beta1. Changes in PKN activity temporally correlates to the G2/M transition timing. Moreover, Cdc25C is phosphorylated by the TGF-beta1-activated PKN. PKN and Cdc25C coimmunoprecipitate with each other. Finally, PKN and Cdc25C colocalize to the nuclear region only during the critical period of time prior to entry into the M phase. Our data demonstrate that Cdc25C activity is negatively regulated by TGF-beta1-stimulated PKN. Once activated through TGF-beta1 signaling, PKN binds to and phosphorylates Cdc25C. The physical interaction and phosphorylation result in an inactivation of Cdc25C and delay the VSMC entry into the M stage of the cell cycle.

Disparities in stage at diagnosis, treatment, and survival in nonelderly adult patients with cancer according to insurance status

PURPOSE

The purpose of this study was to determine the association of insurance status with disease stage at presentation, treatment, and survival among the top 10 most deadly cancers using the SEER database.

PATIENTS AND METHODS

A total of 473,722 patients age 18 to 64 years who were diagnosed with one of the 10 most deadly cancers in the SEER database from 2007 to 2010 were analyzed. A Cox proportional hazards model was used for multivariable analyses to assess the effect of patient and tumor characteristics on cause-specific death.

RESULTS

Overall, patients with non-Medicaid insurance were less likely to present with distant disease (16.9%) than those with Medicaid coverage (29.1%) or without insurance coverage (34.7%; P < .001). Patients with non-Medicaid insurance were more likely to receive cancer-directed surgery and/or radiation therapy (79.6%) compared with those with Medicaid coverage (67.9%) or without insurance coverage (62.1%; P < .001). In a Cox regression that adjusted for age, race, sex, marital status, residence, percent of county below federal poverty level, site, stage, and receipt of cancer-directed surgery and/or radiation therapy, patients were more likely to die as a result of their disease if they had Medicaid coverage (hazard ratio [HR], 1.44; 95% CI, 1.41 to 1.47; P < .001) or no insurance (HR, 1.47; 95% CI, 1.42 to 1.51; P < .001) compared with non-Medicaid insurance.

CONCLUSION

Among patients with the 10 most deadly cancers, those with Medicaid coverage or without insurance were more likely to present with advanced disease, were less likely to receive cancer-directed surgery and/or radiation therapy, and experienced worse survival.

Urotensin II-induced signaling involved in proliferation of vascular smooth muscle cells

The urotensin II receptor, bound by the ligand urotensin II, generates second messengers, ie, inositol triphosphate and diacylglycerol, which stimulate the subsequent release of calcium (Ca²⁺) in vascular smooth muscle cells. Ca²⁺ influx leads to the activation of Ca²⁺-dependent kinases (CaMK) via calmodulin binding, resulting in cellular proliferation. We hypothesize that urotensin II signaling in pulmonary arterial vascular smooth muscle cells (Pac1) and primary aortic vascular smooth muscle cells (PAVSMC) results in phosphorylation of Ca²⁺/calmodulin-dependent kinases leading to cellular proliferation. Exposure of Pac1 cultures to urotensin II increased intracellular Ca²⁺, subsequently activating Ca²⁺/calmodulin-dependent kinase kinase (CaMKK), and Ca²⁺/calmodulin-dependent kinase Type I (CaMKI), extracellular signal-regulated kinase (ERK 1/2), and protein kinase D. Treatment of Pac1 and PAVSMC with urotensin II increased proliferation as measured by ³H-thymidine uptake. The urotensin II-induced increase in ³H-thymidine incorporation was inhibited by a CaMKK inhibitor. Taken together, our results demonstrate that urotensin II stimulation of smooth muscle cells leads to a Ca²⁺/calmodulin-dependent kinase-mediated increase in cellular proliferation.

Niche-specificity and the variable fraction of the Pectobacterium pan-genome

We compare genome sequences of three closely related soft-rot pathogens that vary in host range and geographical distribution to identify genetic differences that could account for lifestyle differences. The isolates compared, Pectobacterium atrosepticum SCRI1043, P. carotovorum WPP14, and P. brasiliensis 1692, represent diverse lineages of the genus. P. carotovorum and P. brasiliensis genome contigs, generated by 454 pyrosequencing ordered by reference to the previously published complete circular chromosome of P. atrosepticum genome and each other, account for 96% of the predicted genome size. Orthologous proteins encoded by P. carotovorum and P. brasiliensis are approximately 95% identical to each other and 92% identical to P. atrosepticum. Multiple alignment using Mauve identified a core genome of 3.9 Mb conserved among these Pectobacterium spp. Each core genome is interrupted at many points by species-specific insertions or deletions (indels) that account for approximately 0.9 to 1.1 Mb. We demonstrate that the presence of a hrpK-like type III secretion system-dependent effector protein in P. carotovorum and P. brasiliensis and its absence from P. atrosepticum is insufficient to explain variability in their response to infection in a plant. Additional genes that vary among these species include those encoding peptide toxin production, enzyme production, secretion proteins, and antibiotic production, as well as differences in more general aspects of gene regulation and metabolism that may be relevant to pathogenicity.

Performance of a high-rate/high-shear activated sludge bioreactor treating biodegradable wastewater

A high-rate activated sludge (HRAS) bioreactor with high shear venturi aeration was operated in the laboratory at various organic loading rates to evaluate chemical oxygen demand (COD) removal efficiency and sludge production. Organic loading rates two orders of magnitude higher than conventional activated sludge loading were investigated in the modified HRAS reactor for a period of 41 weeks. Filtered COD removal efficiency varied from 81 to 92 % for organic loading rates of 3 to 85 kg COD m(-3) d(-1). Observed sludge yield was determined to be 0.10-0.25 g TSS produced g(-1) COD removed, under hydraulic and solids retention times (SRTs) approaching less than two hours and two days, respectively. Observed sludge yield actually declined as loading increased and SRT decreased. It was concluded that high-shear forces created in the reactor due to intense aeration at high volumetric organic loading rates increased substrate utilization rate, improved filtered COD removal efficiency, and kept sludge yields relatively low (despite the very low operating SRTs).

Empirically examining the risk of intimate partner violence: the revised Domestic Violence Screening Instrument (DVSI-R)

OBJECTIVE

This study extends recent research on assessing the risk of intimate partner violence by determining the concurrent and predictive validity of a revised version of the Domestic Violence Screening Instrument (DVSI-R) and whether evidence of such validity is sustained independent of perpetrator demographic characteristics and forms of intimate violence. The analyses highlight violent incidents involving multiple victims as an indicator of "severe" violence. Previous research did not address these issues.

METHODS

Data were analyzed on 14,970 assessments conducted in the State of Connecticut from September 1, 2004 through May 2, 2005. Hierarchical regression and receiver operating characteristic analyses were used to address the objectives of this research.

RESULTS

The empirical findings support the concurrent and predictive validity of the DVSI-R and show that it is robust in its applicability. The findings further show that incidents involving multiple victims are highly associated with DVSI-R risk scores and recidivistic violence.

CONCLUSION

Validating and demonstrating the robustness of a risk assessment instrument is only a first step in preventing violence involving intimate partners or others in family or family-like relationships. The challenge is to train professionals responsible for addressing the problem of such violence to link valid risk assessments to well-crafted strategies of supervision and treatment so that the victimized or other potential victims are protected and perpetrators are held accountable for their actions.

Transforming growth factor-beta1-induced expression of smooth muscle marker genes involves activation of PKN and p38 MAPK

Differentiated vascular smooth muscle cells (SMCs) exhibit a work phenotype characterized by expression of several well documented contractile apparatus-associated proteins. However, SMCs retain the ability to de-differentiate into a proliferative phenotype, which is involved in the progression of vascular diseases such as atherosclerosis and restenosis. Understanding the mechanisms involved in maintaining SMC differentiation is critical for preventing proliferation associated with vascular disease. In this study, the molecular mechanisms through which transforming growth factor-beta1 (TGF-beta1) induces differentiation of SMCs were examined. TGF-beta1 stimulated actin re-organization, inhibited cell proliferation, and up-regulated SMC marker gene expression in PAC-1 SMCs. These effects were blocked by pretreatment of cells with either HA1077 or Y-27632, which inhibit the kinases downstream of RhoA. Moreover, TGF-beta1 activated RhoA and its downstream target PKN. Overexpression of active PKN alone was sufficient to increase the transcriptional activity of the promoters that control expression of smooth muscle (SM) alpha-actin, SM-myosin heavy chain, and SM22alpha. In addition, PKN increased the activities of serum-response factor (SRF), GATA, and MEF2-dependent enhancer-reporters. RNA interference-mediated inhibition of PKN abolished TGF-beta1-induced activation of SMC marker gene promoters. Finally, examination of MAPK signaling demonstrated that TGF-beta1 increased the activity of p38 MAPK, which was required for activation of the SMC marker gene promoters. Co-expression of dominant negative p38 MAPK was sufficient to block PKN-mediated activation of the SMC marker gene promoters as well as the serum-response factor, GATA, and MEF2 enhancers. Taken together, these results identify components of an important intracellular signaling pathway through which TGF-beta1 activates PKN to promote differentiation of SMCs.

Multicolor FISH mapping of the dioecious model plant, Silene latifolia

Silene latifolia is a key plant model in the study of sex determination and sex chromosome evolution. Current studies have been based on genetic mapping of the sequences linked to sex chromosomes with analysis of their characters and relative positions on the X and Y chromosomes. Until recently, very few DNA sequences have been physically mapped to the sex chromosomes of S. latifolia. We have carried out multicolor fluorescent in situ hybridization (FISH) analysis of S. latifolia chromosomes based on the presence and intensity of FISH signals on individual chromosomes. We have generated new markers by constructing and screening a sample bacterial artificial chromosome (BAC) library for appropriate FISH probes. Five newly isolated BAC clones yielded discrete signals on the chromosomes: two were specific for one autosome pair and three hybridized preferentially to the sex chromosomes. We present the FISH hybridization patterns of these five BAC inserts together with previously described repetitive sequences (X-43.1, 25S rDNA and 5S rDNA) and use them to analyze the S. latifolia karyotype. The autosomes of S. latifolia are difficult to distinguish based on their relative arm lengths. Using one BAC insert and the three repetitive sequences, we have constructed a standard FISH karyotype that can be used to distinguish all autosome pairs. We also analyze the hybridization patterns of these sequences on the sex chromosomes and discuss the utility of the karyotype mapping strategy presented to study sex chromosome evolution and Y chromosome degeneration.

CaM kinase IIdeltaC phosphorylation of 14-3-3beta in vascular smooth muscle cells: activation of class II HDAC repression

The myocyte enhancer factor-2 (MEF2) family of transcription factors regulates transcription of muscle-dependent genes in cardiac, skeletal and smooth muscle. They are activated by calcium/calmodulin (CaM)-dependent protein kinases I and IV and silenced by CaM KIIdeltaC. MEF2 is held in an inactive form by the class II histone deacetylases (HDAC) until phosphorylated by either CaM kinase I or IV. Upon phosphorylation, HDAC is transported out of the nucleus via a 14-3-3 dependent mechanism freeing MEF2 to drive transcription. The 14-3-3 chaperone protein exists as a homodimer. In the region of homodimerization, there are two canonical CaM kinase II phosphorylation sites (ser60 and ser65). In vitro phosphorylation assay results indicate that 14-3-3beta is indeed a substrate for CaM kinase II. We hypothesize that CaM kinase IIdeltaC phosphorylation of 14-3-3beta will disrupt homodimer formation resulting in the return of HDAC to the nucleus and their reassociation with MEF2. To test this, we mutated serines 60 and 65 of 14-3-3beta to aspartates to mimic the phosphorylated state. In MEF2 enhancer-reporter assays in smooth muscle cells, expression of the 14-3-3beta double mutant attenuated MEF2-enhancer activity driven by CaM kinase I or IV. The intracellular fate of HDAC4 was followed by transfection of smooth muscle cells with an HDAC4-Green Fluorescent Protein fusion hybrid. The 14-3-3beta double mutant prevented HDAC4 cytoplasmic localization in the presence of active CaM kinase I or IV. These data suggest that the mechanism of CaM kinase IIdeltaC silencing of MEF-2-dependent genes is by phosphorylation of 14-3-3beta, which allows HDAC to return to the nucleus to reform a complex with MEF2, thereby silencing MADS box-dependent gene induction in smooth muscle.

Tetracycline-inducible CaM kinase II silences hypertrophy-sensitive gene expression in rat neonate cardiomyocytes

Recent work from this laboratory both in rat primary cardiomyocytes and in ventricular tissue of transgenic mouse models of induced hypertrophy has identified two Ca(2+)/calmodulin-dependent nuclear signaling cascades. The first involves the phosphatase calcineurin (CaN). The second is the CaM kinase kinase cascade which involves CaM kinase I and CaM kinase IV. Each of these signaling cascades strongly up-regulate transcription of hypertrophy-sensitive genes in the rat ventricular cardiomyocyte. We have documented that over-expression of an active form of CaM kinase II silenced transcriptional induction of hypertrophy-sensitive genes. The purpose of this study was to generate an inducible CaM kinase II expression system and correlate its expression with the silencing of hypertrophic-sensitive reporters. A truncated form of CaM KII, CaM KII (1-290) was subcloned downstream and proximal to a promoter under transcriptional control (induction) of the tetracycline-regulated transcription factor, tet-TransActivator (tTA). Hypertrophy-sensitive reporter activity in primary cardiomyocytes was silenced when tet-inducible CaM KII was co-expressed with plasmids harboring active forms of CaN, CaM KI or CaM KIV. For instance, induced CaM KII expression silenced CaN, CaM kinase I, or CaM kinase IV driven ANF reporter activity 4.9-, 2.9-, and 6.9-fold below their maximal values, respectively. Myocyte exposure to doxycycline (DOX) blocked tTA-driven CaM KII expression and restored CaN/CaM KI or CaN/CaM KIV driven reporter activation. This study demonstrates, for the first time, that active CaM KII silences Ca(2+)-sensitive nuclear signaling cascades for transcriptional up-regulation of cardiomyocyte hypertrophy.

CaM kinase signaling induces cardiac hypertrophy and activates the MEF2 transcription factor in vivo

Hypertrophic growth is an adaptive response of the heart to diverse pathological stimuli and is characterized by cardiomyocyte enlargement, sarcomere assembly, and activation of a fetal program of cardiac gene expression. A variety of Ca(2+)-dependent signal transduction pathways have been implicated in cardiac hypertrophy, but whether these pathways are independent or interdependent and whether there is specificity among them are unclear. Previously, we showed that activation of the Ca(2+)/calmodulin-dependent protein phosphatase calcineurin or its target transcription factor NFAT3 was sufficient to evoke myocardial hypertrophy in vivo. Here, we show that activated Ca(2+)/calmodulin-dependent protein kinases-I and -IV (CaMKI and CaMKIV) also induce hypertrophic responses in cardiomyocytes in vitro and that CaMKIV overexpressing mice develop cardiac hypertrophy with increased left ventricular end-diastolic diameter and decreased fractional shortening. Crossing this transgenic line with mice expressing a constitutively activated form of NFAT3 revealed synergy between these signaling pathways. We further show that CaMKIV activates the transcription factor MEF2 through a posttranslational mechanism in the hypertrophic heart in vivo. Activated calcineurin is a less efficient activator of MEF2-dependent transcription, suggesting that the calcineurin/NFAT and CaMK/MEF2 pathways act in parallel. These findings identify MEF2 as a downstream target for CaMK signaling in the hypertrophic heart and suggest that the CaMK and calcineurin pathways preferentially target different transcription factors to induce cardiac hypertrophy.

The outcome of pregnancy in Kell alloimmunisation

OBJECTIVE

To assess management and outcome of pregnancies with anti-Kell in the West Midlands in the UK over 13 years.

DESIGN

A retrospective review of casenotes.

SETTING

A regional referral clinic for red cell alloimmune disease and fetal medicine unit at a university hospital.

POPULATION

Sixty-five pregnancies were identified in 52 Kell-sensitised women with Kell positive partners from the records of the Birmingham Blood Transfusion Centre.

METHODS

Information from the casenotes was entered on a database and comparisons were made using the SPSS for Windows statistics package.

MAIN OUTCOME MEASURES

Mode of sensitisation, degree of fetal or neonatal anaemia, need for transfusion, gestation at delivery, birthweight and pregnancy outcome.

RESULTS

Alloimmunisation was transfusion-related in 29 pregnancies and pregnancy-induced in 33. The cause could not be identified in three cases. There were 22 proven Kell positive fetuses, of which 18 were affected, in which alloimmunisation was pregnancy-related in 12 cases and transfusion-related in five. Antibody titres and amniotic fluid OD450 were not helpful in management. Severe or very severe disease occurred in 50% of the affected pregnancies (9/18). There was no difference in pregnancy outcome between transfusion or pregnancy induced sensitisation.

CONCLUSIONS

Anti-Kell alloimmunisation is an uncommon cause of serious anaemia in a significant proportion of affected pregnancies. There appears to be no difference between that caused by pregnancy or transfusion. Estimation of fetal haemoglobin concentration by cordocentesis is recommended, as antibody titres and amniocentesis are not helpful.

Prenatal diagnosis and outcome in sacrococcygeal teratomas: a review of cases between 1992 and 1998

A review of sacrococcygeal teratomas diagnosed in the antenatal period in the West Midlands region over a six year interval is reported. The aim of the study was to assess the contribution of ultrasound scanning to the management of cases and to determine the outcome of prenatally diagnosed sacrococcygeal teratomas. A retrospective review of 10 cases was performed to obtain pregnancy details, ultrasound scan data and outcome information. Two fetuses were electively aborted. Perinatal mortality was 62.5% in the remaining cases with all stillbirths and neonatal deaths occurring in babies delivered preterm (at or before 34 weeks' gestation). Marked increase in tumour size (mainly vascular/solid) was observed in five of the fetuses, which was often associated with local compression effects and the development of hydrops. Eight out of 10 cases were delivered vaginally, one following aspiration of the large cystic tumour. Three of the four neonates surviving to surgery underwent successful resection of their benign tumours. As well as guiding prognosis, serial ultrasound scans may also allow the mode of delivery to be planned more effectively. The importance of a multidisciplinary team approach to these difficult cases is emphasized.

Technical advance: single pollen typing combined with laser-mediated manipulation

We combined single pollen typing with laser-mediated manipulation. After drilling a hole in the wall of a pollen grain from a dioecious plant (Silene latifolia) with a UV-laser microbeam, the single pollen grain was recovered directly in the cap of a PCR tube, using a non-contact method called laser pressure catapulting. The entire genome of the single pollen grain was then amplified with improved primer-extension-preamplification PCR (I-PEP PCR). Nested PCR with sequence tagged site (STS)-specific primers was used to analyze several loci in the haploid genome. The single copy gene MROS1 was detected in most of the single pollen grains analyzed. Bgl10, which is localized on the Y chromosome, was detected in approximately half of the pollen grains. MROS3 is reported to be localized on the X chromosome. Using inverse PCR, we isolated two genomic clones of MROS3: MROS3A and MROS3B. The single pollen analysis using nested PCR showed that MROS3A and MROS3B are derived from different loci that are not located on the X chromosome. Single pollen typing not only reveals sex chromosome-linkage within the haploid genome, but can also discriminate between alleles and different loci. This method should also be useful for measuring recombination frequencies without genetic crossover analysis.

A calcineurin-dependent transcriptional pathway for cardiac hypertrophy

In response to numerous pathologic stimuli, the myocardium undergoes a hypertrophic response characterized by increased myocardial cell size and activation of fetal cardiac genes. We show that cardiac hypertrophy is induced by the calcium-dependent phosphatase calcineurin, which dephosphorylates the transcription factor NF-AT3, enabling it to translocate to the nucleus. NF-AT3 interacts with the cardiac zinc finger transcription factor GATA4, resulting in synergistic activation of cardiac transcription. Transgenic mice that express activated forms of calcineurin or NF-AT3 in the heart develop cardiac hypertrophy and heart failure that mimic human heart disease. Pharmacologic inhibition of calcineurin activity blocks hypertrophy in vivo and in vitro. These results define a novel hypertrophic signaling pathway and suggest pharmacologic approaches to prevent cardiac hypertrophy and heart failure.

Conserved expression of a TASSELSEED2 homolog in the tapetum of the dioecious Silene latifolia and Arabidopsis thaliana

To investigate the genetics of male sex determination and stamen development in the dioecious plant Silene latifolia (white campion), male-specific transcripts were isolated from developing flowers by cDNA subtraction. One of the cDNAs identified, STA1, had high DNA and amino acid sequence homology to the male sex determining gene of Zea mays (maize), TASSELSEED2. Both genes are expressed in male and not in female flowers, However, they do not share the same expression pattern. The TASSELSEED2 gene product is expressed in the gynoecium primordia of male maize flowers where it is necessary for pistil abortion. STA1 is not expressed in the gynoecium primordia of male white campion and therefore its gene product cannot perform the same function in sex determination that TASSELSEED2 performs in maize. STA1 is expressed in tapetal cells of white campion male flowers and of white campion hermaphroditic mutants. A homologous gene is also expressed in the tapetum of hermaphroditic Silene species. Tapetal expression of a homologous gene (named ATA1) was also found in Arabidopsis thaliana. The similarity in primary sequence and expression pattern of STA1 and ATA1 indicate that these genes have a conserved role in tapetum development.

Isolation of Y chromosome-specific sequences from Silene latifolia and mapping of male sex-determining genes using representational difference analysis

The genomic subtraction method representational difference analysis (RDA) was used to identify male-specific restriction fragments in the dioecious plant Silene latifolia. Male-specific restriction fragments are linked to the male sex chromosome (the Y chromosome). Four RDA-derived male-specific restriction fragments were used to identify polymorphisms in a collection of X-ray-generated mutant plants with either hermaphroditic or asexual flowers. Some of the mutants have cytologically detectable deletions in the Y chromosome that were correlated with loss of male-specific restriction fragments. One RDA-derived probe detected a restriction fragment present in all mutants, indicating that each has retained Y chromosomal DNA. The other three probes detected genomic fragments that were linked in a region deleted in some hermaphroditic and some asexual mutants. Based on the mutant phenotypes and the correlation of cytologically visible deletions with loss of male-specific restriction fragments, these markers were assigned to positions on the Y chromosome close to the carpel suppression locus. This RDA mapping also revealed a Y-linked locus, not previously described, which is responsible for early stamen development.

Functional cis-element sequence requirements for suppression of gene expression by the TNPA protein of the Zea mays transposon En/Spm

TNPA, one of the two transposition proteins encoded by the En/Spm transposable elements of Zea mays, suppresses the expression of genes that contain an appropriate cis element. Suppression can be monitored in tobacco protoplasts in a transient expression assay as follows. The plant promoter-driven expression of the Escherichia coli-glucuronidase (GUS)-encoding gene, uidA, is repressed in the presence of TNPA if the GUS gene contains a functional cis element in the untranslated RNA leader sequence. Earlier, we found that the minimal cis element is composed of two 12 bp sequences in a tail-to-tail inverted orientation. Each 12 bp sequence is sufficient to bind TNPA in vitro and can be thought of as a half-site in the cis element. Here, we investigated the sequence requirements of the minimal cis element. Our observations support our expectations that a functional cis element must provide a template to which two TNPA molecules can bind in the correct orientation. Sequences within the half-sites can be altered as long as the eight bases that make up the consensus binding sites are not changed. However, we found the following unexpected sequence specificities. Firstly, some changes to the consensus binding sequence can be tolerated in one half-site, as long as the other site matches the consensus. Secondly, although the region between the half-sites can vary in sequence and in length between two and four bases, a thymidine residue is not tolerated directly 5' preceding the second half-site.(ABSTRACT TRUNCATED AT 250 WORDS)

Production, purification, and characterization of human recombinant IL-8 from the eucaryotic vector expression system baculovirus

The cDNA for the human chemotactic interleukin, IL-8, was subcloned from a bacterial source into the eucaryotic vector expression system baculovirus. Recombinant human IL-8 (rhIL-8) was synthesized and secreted from Sf9 cells derived from Spodoptera frugiperda following infection of a recombinant virus harboring the full-length IL-8 structural gene. Infected Sf9 cells produced rhIL-8 in a range from 0.5 to 2.0 mg of rhIL-8/liter of postinfection cell culture media. The recombinant interleukin was purified (greater than 600-fold) to homogeneity using preparative HPLC. rhIL-8 retained all of the physical, immunological, and biochemical properties observed for the natural product, monocyte-derived IL-8. rhIL-8 was assessed for biological efficacy by three criteria: (a) ability to induce chemotaxis in human neutrophils, (b) ability to induce oxygen burst metabolism, and (c) ability to be recognized by purified rabbit antibody generated against monocyte-derived IL-8. Antibody generated against monocyte-derived IL-8 recognized rhIL-8 isolated during all stages of the purification protocol. rhIL-8 was strongly chemotactic for human neutrophils and exhibited a chemotactic index comparable to that reported for other strong chemotactic peptides. rhIL-8 was identified following sodium dodecyl sulfate-polyacrylamide gel electrophoresis as a single silver-stained band having an estimated molecular weight of 9.2 kDa and displayed amino acid residue molar abundance homology predicted for the mature form of the interleukin. Baculovirus vector expression coupled to preparative HPLC proved to be a very efficient method for large-scale recombinant interleukin production.

Rapid isolation of triosephosphate isomerase utilizing high-performance liquid chromatography

A new method for the isolation of homogeneous triosephosphate isomerase (TPI, EC 5.3.1.1) has been developed. The method utilizes high-performance liquid chromatography on DEAE 5PW and Hydrophase-polyethyleneimine columns, which results in the rapid isolation and essentially quantitative recovery of the enzyme. The procedure is superior to previous methods with respect to specificity, recovery, and time. In addition, this rapid process minimizes the potential for postsynthetic modifications of the protein. Milligram quantities of TPI can be isolated from 100 g of tissue.

En/Spm encoded tnpA protein requires a specific target sequence for suppression

The En/Spm encoded suppressor function has been reconstituted in transgenic tobacco protoplasts. The suppressor affects genes which contain an En/Spm responsive transposable element in the transcribed sequences. The En/Spm encoded protein tnpA binds a defined cis element in the inserted transposon, repressing expression of the adjacent gene. This was shown by monitoring transient expression of a bacterial marker gene (GUS) expressed from a strong plant viral promoter. Suppressible variants of the marker gene were produced by inserting I element sequences into the untranslated sequences of the GUS transcript. Comparison of transient expression of these variants in wildtype tobacco protoplasts with their expression in protoplasts transgenic for tnpA protein demonstrates that tnpA is the suppressor. In addition, the minimal cis element required for suppression has been defined as a dimer consisting of two 12 bp tnpA binding sequences in a particular inverted orientation. One of these dimers occurs in each En/Spm end close to the characteristic 13 bp terminal inverted repeat. TnpA binding sites in different arrangements do not respond as well to tnpA. The implications of this observation are discussed. This system can be used to analyse tnpA-DNA interactions involved in gene regulation further.

Identification and characterization of a locus inhibiting extrachromosomal maintenance of the Streptomyces plasmid SLP1

We report here the existence and initial characterization of a genetic locus (imp) that inhibits maintenance of SLP1-derived plasmids as extrachromosomal replicons in a manner distinct from normal incompatibility between autonomous SLP1 replicons. The trans-acting imp function has been localized to a 1.8 kb Eco47III restriction fragment present on integrated SLP1 elements. At least part of this DNA segment is absent from SLP1-derived plasmids. DNA sequence analysis of the imp region indicates that it contains three overlapping open reading frames (ORFs) that may constitute a polycistronic operon. The effects of insertions within the imp region indicate that uninterrupted transcription through all three ORFs is necessary for imp activity.

Characterization of the cell surface receptors for human B cell growth factor of 12,000 molecular weight

Quiescent normal human B cells have been shown to require an activation step before proliferating in response to B cell growth factor (BCGF) of 12,000 m.w. (12 kd). One effect of cell activation has been the putative acquisition of specific cell surface growth factor receptors. In this report, the existence of such receptors has been confirmed by using purified radioiodinated BCGF-12 kd. BCGF-12 kd receptors on activated B cells have been shown to be distinct form those interacting with IL 2. Scatchard analysis revealed both high affinity receptor sites with an apparent Kd of 28.6 pM and low affinity receptor sites with Kd of 1.2 nM on freshly prepared, anti-IgM activated peripheral blood B cells. Human B cells grown in culture for extended periods of time in the presence of BCGF-12 kd also displayed high affinity receptor sites (Kd, 41.4 pM) and low affinity receptor sites (Kd, 0.9 nM). The action of BCGF-12 kd therefore appears to be mediated by binding to its lineage-specific receptors on the cell surface.

Characterization of the cell surface receptors for human B cell growth factor of 12,000 molecular weight

Quiescent normal human B cells have been shown to require an activation step before proliferating in response to B cell growth factor (BCGF) of 12,000 m.w. (12 kd). One effect of cell activation has been the putative acquisition of specific cell surface growth factor receptors. In this report, the existence of such receptors has been confirmed by using purified radioiodinated BCGF-12 kd. BCGF-12 kd receptors on activated B cells have been shown to be distinct form those interacting with IL 2. Scatchard analysis revealed both high affinity receptor sites with an apparent Kd of 28.6 pM and low affinity receptor sites with Kd of 1.2 nM on freshly prepared, anti-IgM activated peripheral blood B cells. Human B cells grown in culture for extended periods of time in the presence of BCGF-12 kd also displayed high affinity receptor sites (Kd, 41.4 pM) and low affinity receptor sites (Kd, 0.9 nM). The action of BCGF-12 kd therefore appears to be mediated by binding to its lineage-specific receptors on the cell surface.

Oligosaccharyltransferase activity is markedly increased during differentiation of a nonfusing myoblast cell line

We have studied several aspects of glycoprotein synthesis in myoblast differentiation by using a nonfusing myoblast cell line, BC3H1. Previous studies showed that transfer of proliferating undifferentiated BC3H1 cells to mitogen-depleted medium results in the cells' withdrawal from the cell cycle and induction of a variety of muscle-specific gene products [E. N. Olson, L. Glaser, J. P. Merlie, R. Sebane, and J. Lindstrom (1983) J. Biol. Chem. 258, 13946-13953]. Because cell surface glycoproteins have been implicated in myoblast differentiation, in the present study we measured the amount of oligosaccharyltransferase in microsomes isolated from BC3H1 cells at various stages of differentiation. By using an acceptor peptide containing the sequence-Asn-Leu-Thr-, enzyme activity was measured by formation of [3H]glycopeptide. In addition, active enzyme protein was measured with a 125I-labeled photoreactive derivative of the acceptor tripeptide. Both of these independent assay methods revealed a marked increase in oligosaccharyltransferase when differentiation was induced by serum depletion. Moreover, mitogenic stimulation of differentiated cells resulted in a return of oligosaccharyltransferase to near basal levels. This reversible increase in this key enzyme in protein glycosylation occurred despite the fact that both total protein and glycoprotein synthesis were depressed during differentiation. These data indicate that during myogenesis the level of oligosaccharyltransferase is regulated in parallel with a number of muscle-specific gene products. These results are discussed in the context of regulation of the pathway of glycoprotein synthesis.

beta-Adrenergic stimulation alters oligosaccharide pyrophosphoryl dolichol metabolism in rat parotid acinar cells

beta-Adrenergic stimulation of rat parotid acinar cells markedly increases [3H]mannose incorporation into N-linked glycoproteins [Kousvelari, Grant, Banerjee, Newby & Baum (1984) Biochem. J. 222, 17-24]. More than 90% of this protein-bound [3H]mannose was preferentially incorporated into four secretory glycoproteins. The ratio of [3H]mannose/[14C]leucine present in these individual proteins was 1.7-4-fold greater with isoproterenol-treated cells than with untreated controls. In isoproterenol-stimulated cells, [3H]mannose incorporation into mannosylphosphoryl dolichol and oligosaccharide-PP-dolichol was increased 2-3-fold over that observed in unstimulated cells. Similarly, formation of mannosylated oligosaccharide-PP-dolichol was increased approx. 4-fold in microsomes prepared from isoproterenol-treated cells. Also, turnover of oligosaccharide-PP-dolichol was significantly increased (5-fold) by beta-adrenergic stimulation; the half-life for oligosaccharide-PP-dolichol decreased from 6 min in control cells to 1.2 min in isoproterenol-stimulated cells. By 15 min after isoproterenol addition to acinar cells, the specific radioactivity of parotid oligosaccharide moieties increased about 3-fold over the value observed in the absence of the agonist. Taken together, these results strongly suggest that elevation of N-linked protein glycosylation in rat parotid acinar cells after beta-adrenoreceptor stimulation resulted from significant enhancement in the synthesis of mannosylphosphoryl dolichol and oligosaccharide-PP-dolichol and the turnover of oligosaccharide-PP-dolichol.

Cyclic AMP mediates beta-adrenergic-induced increases in N-linked protein glycosylation in rat parotid acinar cells

beta-Adrenergic stimulation of rat parotid cells by isoprenaline (isoproterenol) results in 2-3-fold increases in [3H]mannose incorporation into N-linked oligosaccharides. This occurs without perceptible lag and is linear with time for 60 min after agonist addition. Concomitantly, isoprenaline markedly increases cellular cyclic AMP. Examination of individual proteins by sodium dodecyl sulphate/polyacrylamide-gradient-gel electrophoresis reveals that glycosylation changes are primarily associated with four secretory proteins, of approx. Mr 17000, 32000, 38000 and 220000. Beta-Adrenoreceptor activation additionally elicits a slight increase in parotid protein synthesis. The greatest increase in [14C]leucine incorporation is that into another secretory protein (Mr approx. 24000). Exposure of cells to dibutyryl cyclic AMP yields results comparable with those after isoprenaline treatment. Forskolin, which increases parotid-cell cyclic AMP, also causes similar effects. Conversely, dibutyryl cyclic GMP shows no such response. The data are consistent with the notion that beta-adrenergic stimulation of N-linked protein glycosylation in rat parotid cells is mediated by cyclic AMP.