The crystal structure of bacteriophage λ RexA provides novel insights into the DNA binding properties of Rex-like phage exclusion proteins

RexA and RexB function as an exclusion system that prevents bacteriophage T4rII mutants from growing on Escherichia coli λ phage lysogens. Recent data established that RexA is a non-specific DNA binding protein that can act independently of RexB to bias the λ bistable switch toward the lytic state, preventing conversion back to lysogeny. The molecular interactions underlying these activities are unknown, owing in part to a dearth of structural information. Here, we present the 2.05-Å crystal structure of the λ RexA dimer, which reveals a two-domain architecture with unexpected structural homology to the recombination-associated protein RdgC. Modelling suggests that our structure adopts a closed conformation and would require significant domain rearrangements to facilitate DNA binding. Mutagenesis coupled with electromobility shift assays, limited proteolysis, and double electron-electron spin resonance spectroscopy support a DNA-dependent conformational change. In vivo phenotypes of RexA mutants suggest that DNA binding is not a strict requirement for phage exclusion but may directly contribute to modulation of the bistable switch. We further demonstrate that RexA homologs from other temperate phages also dimerize and bind DNA in vitro. Collectively, these findings advance our mechanistic understanding of Rex functions and provide new evolutionary insights into different aspects of phage biology.

Safety and efficacy of tenecteplase in patients with wake-up stroke assessed by non-contrast CT (TWIST): a multicentre, open-label, randomised controlled trial

BACKGROUND

Current evidence supports the use of intravenous thrombolysis with alteplase in patients with wake-up stroke selected with MRI or perfusion imaging and is recommended in clinical guidelines. However, access to advanced imaging techniques is often scarce. We aimed to determine whether thrombolytic treatment with intravenous tenecteplase given within 4·5 h of awakening improves functional outcome in patients with ischaemic wake-up stroke selected using non-contrast CT.

METHODS

TWIST was an investigator-initiated, multicentre, open-label, randomised controlled trial with blinded endpoint assessment, conducted at 77 hospitals in ten countries. We included patients aged 18 years or older with acute ischaemic stroke symptoms upon awakening, limb weakness, a National Institutes of Health Stroke Scale (NIHSS) score of 3 or higher or aphasia, a non-contrast CT examination of the head, and the ability to receive tenecteplase within 4·5 h of awakening. Patients were randomly assigned (1:1) to either a single intravenous bolus of tenecteplase 0·25 mg per kg of bodyweight (maximum 25 mg) or control (no thrombolysis) using a central, web-based, computer-generated randomisation schedule. Trained research personnel, who conducted telephone interviews at 90 days (follow-up), were masked to treatment allocation. Clinical assessments were performed on day 1 (at baseline) and day 7 of hospital admission (or at discharge, whichever occurred first). The primary outcome was functional outcome assessed by the modified Rankin Scale (mRS) at 90 days and analysed using ordinal logistic regression in the intention-to-treat population. This trial is registered with EudraCT (2014-000096-80), ClinicalTrials.gov (NCT03181360), and ISRCTN (10601890).

FINDINGS

From June 12, 2017, to Sept 30, 2021, 578 of the required 600 patients were enrolled (288 randomly assigned to the tenecteplase group and 290 to the control group [intention-to-treat population]). The median age of participants was 73·7 years (IQR 65·9-81·1). 332 (57%) of 578 participants were male and 246 (43%) were female. Treatment with tenecteplase was not associated with better functional outcome, according to mRS score at 90 days (adjusted OR 1·18, 95% CI 0·88-1·58; p=0·27). Mortality at 90 days did not significantly differ between treatment groups (28 [10%] patients in the tenecteplase group and 23 [8%] in the control group; adjusted HR 1·29, 95% CI 0·74-2·26; p=0·37). Symptomatic intracranial haemorrhage occurred in six (2%) patients in the tenecteplase group versus three (1%) in the control group (adjusted OR 2·17, 95% CI 0·53-8·87; p=0·28), whereas any intracranial haemorrhage occurred in 33 (11%) versus 30 (10%) patients (adjusted OR 1·14, 0·67-1·94; p=0·64).

INTERPRETATION

In patients with wake-up stroke selected with non-contrast CT, treatment with tenecteplase was not associated with better functional outcome at 90 days. The number of symptomatic haemorrhages and any intracranial haemorrhages in both treatment groups was similar to findings from previous trials of wake-up stroke patients selected using advanced imaging. Current evidence does not support treatment with tenecteplase in patients selected with non-contrast CT.

FUNDING

Norwegian Clinical Research Therapy in the Specialist Health Services Programme, the Swiss Heart Foundation, the British Heart Foundation, and the Norwegian National Association for Public Health.

Consenting practices in interventional cardiology: an analysis from the European Association of Percutaneous Cardiovascular Interventions (EAPCI)

Background

Consenting practices in interventional cardiology vary across different procedures, operators, centres and nations.

Purpose

In order to define best practice for obtaining informed patient consent, it is first necessary to understand how consenting practice differs.

Methods

An online survey of 20 questions was sent to all members of the European Association of Percutaneous Cardiovascular Interventions, addressing consenting practices in elective and emergency scenarios.

Results

We received 483 responses from 74 countries. The majority of respondents (77%) were European operators. Responses were received from consultant cardiologists (n=370), fellows in training (n=55), allied health professionals (n=36) and others (n=21).

Across all respondents, in elective practice, 427 (88.4%) operators obtain written consent for every procedure, the remainder (9.5%) obtain verbal consent only. Consent is obtained by the consultant or fellow who directly performs the procedure in 56.9% cases. For coronary angiography, pre-emptive consent for possible additional procedures (pressure wire and PCI) is taken by operators in all cases (58.6%), some cases (30.6%) and never (11.0%). Prior to interventional therapies, written information detailing the risk of the procedure is provided in every case by 63.8% of operators, sometimes by 25.1% of operators, and is never provided by 11.0% of operators.

In emergency settings, where patients are conscious and have capacity to consent, 274 (56.7%) of respondents obtain written consent, 155 (33.1%) obtain verbal consent only and 52 (10.8%) stated that a consent process was not required. Where consciousness and capacity are impaired, 218 (45.1%) always, 118 (24.4%) sometimes and 145 (30%) never document a written capacity and best interests' assessment.

When asked to rate the overall quality of consenting practices in their own institution, 279 (57.8%) stated these were “excellent” or “above average”, 165 (34.2%) were “average” and 39 operators described consenting practices in their institution as “below average” or “poor”.

Conclusions

Diversity in consenting practice spans elective and emergency procedures. These results suggest that there is substantial variation in the understanding of the rationale, legal requirement, and perceived best practices for consent. Further work should consider the merits of standardisation of consent processes across Europe.

Funding Acknowledgement

Type of funding sources: None.

Dental Service and Resource Needs during COVID-19 among Underserved Populations

Introduction:

In response to the coronavirus disease 2019 (COVID-19) outbreak, dental services in British Columbia, Canada, were restricted to urgent and emergency cases between March 16 and May 18, 2020. It is unclear how the curtailment of oral health services has affected underserved populations who already often have limited access to dental care due to cost, fear, stigma, and discrimination.

Objectives:

To explore the experiences of underserved populations and their community organizations when accessing oral health services and information in British Columbia and identify their coping mechanisms employed during the curtailment of oral health care services.

Methods:

Semistructured, remote interviews were conducted with 13 staff and 18 members from 6 community-based organizations. These organizations serve men and women with a history of incarceration and/or experiencing poverty and homelessness, persons living with human immunodeficiency virus/AIDS, adults living with mental illness, and older adults in long-term care facilities. The interviews were audio-recorded, transcribed verbatim, and coded for emerging themes using NVivo 12 software. Thematic analysis was performed.

Results:

The pandemic raised concerns and hesitancy among underserved populations and further reduced access to care. In turn, those with unmet dental needs resorted to coping mechanisms, including turning to community support or medical services, self-management of dental issues, and not dealing with dental issues altogether. Community organizers and members outlined needed resources such as assistance navigating the dental care system, having a contact for dental-related questions, and member preparation for dental service changes, while emphasizing the importance of positive relationships with dental providers.

Conclusion:

Underserved populations who already face barriers to oral health care services experienced increased difficulty in addressing their oral health needs and concerns during the beginning of the COVID-19 pandemic. Strategies aimed at reaching out to this population and those who support them are needed to help mitigate negative coping strategies and increased oral health disparities.

Knowledge Transfer Statement:

This study depicts ways of addressing unmet oral health–related issues during the COVID-19 pandemic for underserved populations and their community organizations with policy implications as well as practical strategies.

How to: Basics der Schrittmacherprogrammierung

Die Programmierung von Schrittmachersystemen, insbesondere von Zweikammerschrittmachersystemen kann die untersuchenden Ärzte vor große Herausforderungen stellen. Eine genaue Kenntnis der zu programmierenden Parameter sowie der herstellerspezifischen Algorithmen ist essentiell. Bei der Programmierung sollte darauf geachtet werden, die Programmierung den individuellen Bedürfnissen der Patient:innen anzupassen und „Out-of-the-box“-Programmierungen zu vermeiden. Ein weiteres wichtiges Ziel der Programmierung ist es, unnötige Stimulation im rechten Ventrikel zu vermeiden und dem Patienten eine gute Belastbarkeit zu ermöglichen sowie zu vermeiden, dass er eine Stimulation wahrnimmt. Algorithmen der Hersteller können hierbei helfen, müssen jedoch verstanden und bei inadäquatem Verhalten ggf. deaktiviert werden.

Electroanatomic visualization of coronary arteries: a case series to elicit safety, feasibility and diagnostic value in complex ablation procedures

Funding Acknowledgements

Type of funding sources: None.

Background

Although three dimensional (3D) electroanatomic mapping systems allow detailed assessment of anatomy and substrates, ablation still carries substantial risk when close proximity to coronary arteries is suspected. 3D integration of coronary anatomy in mapping systems is still cumbersome, highlighting the need for an option of ad hoc acquirement of coronary artery anatomy. The goal of this case series was to evaluate the feasibility of a wire-based approach to the live visualization of coronary arteries and to assess its diagnostic information regarding procedure guiding.

Methods

For this single center case series, we included procedures in which close proximity of an ablation site to an epicardial vessel had to be suspected. An uninsulated-tip wire was then introduced into the relevant coronaries via diagnostic catheters after exclusion of critical stenosis by coronary angiography. The wire was connected to an impedance based 3D mapping system using a clamp and standard pin connection. Integrating this setup in the mapping system allows for live visualization of the wire tip, as well as the assessment of local electrograms within the respective vessel.

Results

We included a total of 9 procedures (4 ventricular tachycardia (VT) ablation procedures and 5 procedures for the ablation of premature ventricular contractions (PVCs)). The left coronary arteries were mapped in 8 cases, the right coronary artery was mapped in one case. In the majority of cases, the arrhythmogenic substrate was found in the left ventricle (5/9) or left ventricular summit area and the distal coronary sinus respectively (3/9). In two cases, epicardial mapping was performed combined with visualization of the right or left coronary arteries, respectively. There were no complications attributed to coronary wiring and mapping in this case series.

In two cases, the diagnostic information from mapping of the coronary arteries could be used to rule out an epicardial origin of arrhythmia. In the majority of cases, coronary visualization was used to ascertain a proper distance between the ablation site and the vessel.

Discussion

In this case series, we could demonstrate the feasibility and safety of coronary artery visualization and its integration in a 3D mapping system. The data obtained was used for diagnostic, as well as safety aspects. The electrograms from the wire were used to quickly assess relative timing of arrhythmias, thus allowing for an estimation of possible epicardial origin.

Conclusion

Applying the same caveats as for any other wiring of coronary arteries, their electroanatomic visualization is achieved in a safe and straightforward manner, with minimal technical requirements. Mapping of the coronary arteries adds critical diagnostic information and their real-time visualization is feasible without exceeding costs or risks

Evaluation of the Efficacy of Disinfectant Footmats for the Reduction of Bacterial Contamination on Footwear in a Large Animal Veterinary Hospital

Background

Infection control is critical to providing high‐quality patient care. Many veterinary teaching hospitals (VTHs) utilize footbaths or footmats at entrances and key control points throughout the facility to decrease trafficking of pathogenic microorganism on contaminated footwear.

Hypothesis/Objectives

To compare efficacy of 4 disinfectants used in footmats for decreasing bacterial contamination of footwear in a large animal hospital.

Animals

A single adult dairy cow was housed in a stall for 4 days to facilitate stall contamination with fecal material.

Methods

Overboots were experimentally contaminated with organic material in a standardized manner. Each boot was randomly assigned to 1 of 5 treatments (no treatment, or exposure to 1 of 4 disinfectants: an accelerated peroxygen [AHP], a peroxygen [VIRKON], a quaternary ammonium [QUAT], and a phenolic disinfectant [PHENOLIC]) by stepping on a soaked footmat and collecting samples from boot soles. Generalized linear modeling was used to analyze differences in bacterial counts.

Results

Reductions in colony‐forming units (CFUs) on treated boots ranged from no detectable reduction to 0.45 log₁₀ and varied by disinfectant. Percentage reductions in total bacterial counts generally were larger (albeit still modest) for AHP and QUAT disinfectants (range 37–45%) and smallest for the PHENOLIC (no detectable reduction).

Conclusions and Clinical Importance

In general, use of disinfectant footmats was associated with significant reductions in viable bacteria on overboots—albeit with variable efficacy. Footmats may be useful adjuncts to cleaning and disinfection programs for decreasing trafficking of microorganisms throughout VTHs but should not be considered as a sole prevention method.

Characterization of the count rate performance of modern gamma cameras

PURPOSE

Evaluation of count rate performance (CRP) is an integral component of gamma camera quality assurance and system deadtime (τ) may be utilized for image correction in quantitative studies. This work characterizes the CRP of three modern gamma cameras and estimates τ using two established methods (decay and dual source) under a variety of experimental conditions.

METHODS

For the decay method, uncollimated detectors were exposed to a Tc-99m source of relatively high activity and count rates were sampled regularly over 48 h. Input count rate at each time point was based on the lowest observed count rate data point. The input count rate was plotted against the observed count rate and fit via least-squares to the paralyzable detector model (PDM) to estimate τ (rates method). A novel expression for observed counts as a function of measurement time interval was derived, taking into account the PDM and the presence of background but making no assumption regarding input count rate. The observed counts were fit via least-squares to this novel expression to estimate τ (counts method). Correlation and Bland-Altman analyses were performed to assess agreement in estimates of τ between the rates and counts methods. The dependence of τ on energy window definition and incident energy spectrum were characterized. The dual source method was also used to estimate τ and its agreement with estimates from the decay method under identical conditions was also investigated. The dependences of τ on the total activity and the ratio of source activities were characterized.

RESULTS

The observed CRP curves for each gamma camera agreed with the PDM at low count rates but deviated substantially from it at high count rates. The estimates of τ determined from the paralyzable portion of the CPR curve using the rates method and the counts method were found to be highly correlated (r = 0.999) but with a small (~6%) difference. No statistically significant difference was observed between the estimates of τ using the decay or dual source methods under identical experimental conditions (p = 0.13). Estimates of τ increased as a power-law function with decreasing ratio of counts in the photopeak to the total counts. Also, estimates of τ increased linearly as spectral effective energy decreased. No significant difference was observed between the dependences of τ on energy window definition or incident spectrum between the decay and dual source methods. Estimates of τ using the dual source method varied as a quadratic on the ratio of the single source to combined source activities and linearly with total activity.

CONCLUSIONS

The CRP curves for three modern gamma camera models have been characterized, demonstrating unexpected behavior that necessitates the determination of both τ and maximum count rate to fully characterize the CRP curve. τ was estimated under a variety of experimental conditions, based on which guidelines for the performance of CRP testing in a clinical setting have been proposed.

Generating Functions for Multi-labeled Trees

Multi-labeled trees are a generalization of phylogenetic trees that are used, for example, in the study of gene versus species evolution and as the basis for phylogenetic network construction. Unlike phylogenetic trees, in a leaf-multi-labeled tree it is possible to label more than one leaf by the same element of the underlying label set. In this paper we derive formulae for generating functions of leaf-multi-labeled trees and use these to derive recursions for counting such trees. In particular, we prove results which generalize previous theorems by Harding on so-called tree-shapes, and by Otter on relating the number of rooted and unrooted phylogenetic trees.

SU-E-T-86: Development and Implementation of the Use of Optically Stimulated Luminescent Detectors in the Radiological Physics Center Anthropomorphic Quality Assurance Phantoms

PURPOSE

To study the angular dependence of optically stimulated luminescence dosimeters (OSLD) in the Radiological Physics Center anthropomorphic quality assurance pelvic phantom to provide accurate dosimetric measurements as a replacement for TLD.

METHODS

A spherical phantom was constructed to investigate the angular response of the OSLD as oriented in the RPC pelvic phantom. Three OSLD per irradiation angle, placed at the center of the spherical phantom, were irradiated with 100 cGy from six different angles. The angular response at each angle was determined relative to the OSLD response when the beam was incident normally on the OSLD surface. A pelvic phantom dosimetry insert was modified to include both TLD and OSLD. Three treatment plans were developed in Pinnacle v9.0 and one in Accuray's Multiplan, each with increasing angular beam delivery (4 field, IMRT, SmartArc, CyberKnife) for the pelvic phantom using a common dose prescription and constraints. Each plan was delivered to the phantom three times, containing two TLD and two OSLD, oriented in the transverse plane, at the center of the PTV. The dose delivered to the TLD and OSLD was calculated for each treatment and then compared.

RESULTS

The angular dependence correction factor for the spherical phantom was found to be uniformly 1.041 ± 0.003 from single beam edge-on irradiations. The angular dependence correction in the pelvic phantom from multiple beam orientation irradiations was 1.024 ± 0.002, such that the OSLD dose agreed with the TLD dose. Applying the OSLD pelvic phantom correction factor, the RPC measured dose to planning system calculated dose ratio was 0.995 ± 0.009. The established RPC phantom TLD dose to calculated dose ratio was 0.995 ± 0.010.

CONCLUSIONS

An anthropomorphic phantom OSLD angular dependence correction factor was established such that the final OSLD dose measurements agreed with RPC's TLD dose measurements to within 1%. Work supported by grant CA 10953, awarded by NCI, DHHS.

Direct observation of NH2* reactions with oxygen, amino acids, and melanins

We report the direct observation of the quenching of the weakly absorbing transient due to the amino radical by oxygen and, hence determine, by a totally direct method, the corresponding rate constant (k = (1.1 +/- 0.1) x 10(9) dm3 mol(-1) s(-1)). We also report the rate constants for the reactions of the amino radical with several amino acids and models of black eumelanin and blond/red phaeomelanin. These reactions lead to a mechanism, based on free radicals, that can explain why ammonia is useful in commercial hair (melanin) bleaching, avoiding excessive amino acid (hair protein) damage.

Analysis of somatic molecular changes, clinicopathological features, family history, and germline mutations in colorectal cancer families: evidence for efficient diagnosis of HNPCC and for the existence of distinct groups of non-HNPCC families

OBJECTIVE

To analyse somatic molecular changes, clinicopathological features, family history, and germline mutations in families with colorectal cancer (CRC).

METHODS

Molecular changes (K-ras and beta-catenin mutations, chromosome 18q allele loss (LOH), APC LOH, microsatellite instability (MSI), and expression of beta-catenin and p53) were examined in four series of CRC patients with proven or probable hereditary disease: hereditary non-polyposis colon cancer (HNPCC); MYH associated polyposis (MAP); multiple (>5) colorectal adenomas without familial adenomatous polyposis (FAP); and other families/cases referred to family cancer clinics (FCC series). HNPCC was diagnosed using a combination of germline mutation screening and tumour studies. A series of unselected CRC patients was also studied.

RESULTS

There was overlap between genetic pathways followed by each type of CRC, but significant differences included: increased frequency of K-ras mutation and reduced frequency of APC LOH in cancers from MAP, but not from multiple adenoma patients; reduced frequency of LOH in HNPCC CRCs; and increased MSI in CRCs from HNPCC, but not from FCC or multiple adenoma patients. HNPCC was apparently detected efficiently by combined germline and somatic analysis. Cancers from the FCC, unselected, and multiple adenoma series shared similar molecular characteristics. In the FCC and multiple adenoma series, hierarchical cluster analysis using the molecular features of the cancers consistently identified two distinct groups, distinguished by presence or absence of K-ras mutation.

CONCLUSIONS

While K-ras mutation status is known to differentiate hereditary bowel cancer syndromes such as MAP and FAP, it may also distinguish groups of non-HNPCC, FCC patients whose disease has different, as yet unknown, genetic origins.

Exon 3 beta-catenin mutations are specifically associated with colorectal carcinomas in hereditary non-polyposis colorectal cancer syndrome

BACKGROUND AND AIMS

Activating beta-catenin mutations in exon 3 have been implicated in colorectal tumorigenesis. Although reports to the contrary exist, it has been suggested that beta-catenin mutations occur more often in microsatellite unstable (MSI+) colorectal carcinomas, including hereditary non-polyposis colorectal cancer (HNPCC), as a consequence of defective DNA mismatch repair. We have analysed 337 colorectal carcinomas and adenomas, from both sporadic cases and HNPCC families, to provide an accurate assessment of beta-catenin mutation frequency in each tumour type.

METHODS

Direct sequencing of exon 3 of beta-catenin.

RESULTS

Mutations were rare in sporadic (1/83, 1.2%) and HNPCC adenomas (1/37, 2.7%). Most of the sporadic adenomas analysed (80%) were small (<1 cm), and our data therefore differ from a previous report of a much higher mutation frequency in small adenomas. No oncogenic beta-catenin mutations were identified in 34 MSI+ and 78 microsatellite stable (MSI-) sporadic colorectal cancers but a raised mutation frequency (8/44, 18.2%) was found in HNPCC cancers; this frequency was significantly higher than that in HNPCC adenomas (p=0.035) and in both MSI- (p<0.0001) and MSI+ (p=0.008) sporadic cancers. Mutations were more common in higher stage (Dukes' stages C and D) cancers (p=0.001).

CONCLUSION

Exon 3 beta-catenin mutations are associated specifically with malignant colorectal tumours in HNPCC; mutations appear not to result directly from deficient mismatch repair. Our data provide evidence that the genetic pathways of sporadic MSI+ and HNPCC cancers may be divergent, and indicate that mutations in the HNPCC pathway of colorectal tumorigenesis may be determined by selection, not simply by hypermutation.

Refining the Amsterdam Criteria and Bethesda Guidelines: testing algorithms for the prediction of mismatch repair mutation status in the familial cancer clinic

PURPOSE

Hereditary nonpolyposis colon cancer (HNPCC) is a Mendelian dominant syndrome of bowel, endometrial, and other cancers and results from germline mutations in mismatch repair (MMR) genes. HNPCC is now best diagnosed on molecular grounds using MMR mutation screening, aided by microsatellite instability (MSI) and immunohistochemistry in tumors. Selection of families for molecular investigation of HNPCC is usually based on suboptimal methods (Amsterdam Criteria or Bethesda Guidelines), but these can be improved using additional clinical data (mean ages of affected persons and presence of endometrial cancer) in a quantitative model.

METHODS

We have verified the performance of the Wijnen model and have shown that it remains valid when HNPCC is diagnosed using mutation screening, MSI, and immunohistochemistry. We have also set up and verified our own models (Amsterdam-plus and Alternative), which perform at least as well as the Wijnen model.

RESULTS

The Amsterdam-plus model improves on the Amsterdam Criteria by using five extra variables (numbers of colorectal and endometrial cancers in the family, number of patients with five or more adenomas, number with more than one primary cancer of the colorectum or endometrium, and mean age of presentation) and performs better than the Wijnen model. The Alternative model avoids the need to evaluate the Amsterdam Criteria and performs nearly as well as the other models.

CONCLUSION

We believe that a quantitative model, such as the Amsterdam-plus model, should be the first choice for selecting families or patients for evaluation of HNPCC using molecular tests. We present an algorithm for this process.

Phase I study for poor-prognosis lymphoma: Augmentation of the “BEAM” regimen with escalating dose melphalan using amifostine cytoprotection and autologous hematopoietic stem cell transplantation — a preliminary report

We and others have previously shown that the use of amifostine (Ethyol; MedImmune Inc, Gaithersburg, MD) can ameliorate certain regimen-related toxicities of high-dose melphalan (HD-MEL) in the autologous hematopoietic stem cell transplant setting. Our recent experience indicated that the maximum tolerated dose of HD-MEL plus autologous hematopoietic stem cell transplant could be increased from approximately 200 mg/m2 to at least 280 mg/m2 with amifostine. Although a dose-limiting toxicity was not clearly identified, atrial fibrillation was noted in several patients. Phase II trials using this regimen have been reported in lymphoma and myeloma. Nonetheless, it is unlikely that single agent therapy, regardless of dose, will be highly curative in advanced hematologic malignancy. Thus, we used amifostine to permit dose escalation of HD-MEL within the BEAM (BCNU/etoposide/arabinosylcytosine/HD-MEL) combination chemotherapy regimen before autologous hematopoietic stem cell transplant in selected patients with lymphoma. Patient entry at the starting dose (ie, HD-MEL 140 mg/m2) has been completed without the development of severe regimen-related toxicities. This trial is ongoing.

Risk taking as a predictor of adolescent sexual activity and use of contraception

This study tested a risk-taking model of adolescent sexual activity and use of contraception. Longitudinal data were analyzed from a household sample of 1273 unmarried male and female adolescents and young adults. The results indicated that engagement in sexual intercourse and re liability of contraceptive use increased with age throughout adolescence and into young adulthood. Engaging in sexual intercourse among these subjects appeared to reflect a high risk-taking personality profile as de fined by high disinhibition and high impulsivity. Reliable and consistent use of contraception, however, did not appear to relate to this profile. Future research needs to determine other predictors of safe versus unsafe sexual practices.

Implantation of a dual-chamber pacemaker in a patient with persistent left superior vena cava using a a steerable stylet

A persistent left superior vena cava (PLSVC) is a rare abnormality that presents a challenge to the implanter. To our knowledge, this is the first case report of implantation of dual-chamber pacemaker via PLSVC utilizing a steerable stylet (the Locater; St. Jude Medical, Inc., Minnetonka, Minnesota) with chronic follow-up showing stable threshold.

The relationship between interdialytic weight gain and patient compliance. A single centred cohort study (n=21)

Haemodialysis patients are subject to many restrictions and face a lifetime attempting to adhere to various regimes. This small study was designed to explore the relationship between fluid gain, compliance and staff reinforcement. This was achieved by measuring dietetic and nursing educational input using interdialytic weight gain as a barometer of patient compliance. This study suggests renal nurses, dietitians and other members of the multi-disciplinary team may have less influence than previously assumed.

Urinary diversions: a review of nursing care

The nurse plays an important part in the preoperative and postoperative management of the patient with a urinary diversion. Although urinary diversion as a surgical alternative has been performed since the mid 1800s, improvements in technique and management over the past 10 years warrant discussion. Three types of urinary diversion procedures are discussed along with suggestions for optimal nursing management during the postoperative period.

Parental modeling and parenting behavior effects on offspring alcohol and cigarette use. A growth curve analysis

PURPOSE

This paper examined the effects of parental drinking and smoking, parental warmth and hostility, and their interactions on offsprings' drinking and smoking over time.

METHODS

We used four waves of prospective longitudinal data collected from 218 males and 214 females who were age 15 at Time 1 and age 28 by Time 4. Growth mixture modeling was used to develop offspring trajectory groups of cigarette smokers and alcohol drinkers. Logistic regression analyses were conducted to determine whether parent behaviors could predict offspring heavy drinking and smoking trajectories.

RESULTS

Four drinking and three smoking trajectory groups were identified for females and males. Parent drinking rather than parenting behavior predicted heavy drinking by offsprings and mothers' drinking was a slightly better predictor than fathers' drinking for both daughters and sons. Fathers' warmth and hostility was the best predictor of heavy smoking by sons. Neither modeling nor parenting significantly predicted female heavy smoking. For the most part, parent modeling did not interact with parenting behavior to predict smoking or drinking in offspring.

IMPLICATIONS

Parents affected their offspring's use of alcohol and cigarettes both through modeling and parenting behavior. However, the importance of modeling relative to parenting behavior differed by the type of substance. Prevention programs that focus on both the modeling of parental behaviors, as well as enhancing parenting skills, should be effective in influencing trajectories of substance use throughout adolescence and young adulthood.

Paclitaxel and gemcitabine chemotherapy for advanced transitional-cell carcinoma of the urothelial tract: a phase II trial of the Minnie pearl cancer research network

PURPOSE

To evaluate the toxicity and efficacy of combination chemotherapy with paclitaxel and gemcitabine in patients with advanced transitional-cell carcinoma of the urothelial tract.

PATIENTS AND METHODS

Fifty-four patients with advanced unresectable urothelial carcinoma entered this multi-centered, community-based, phase II trial between May 1997 and December 1999. All patients were treated with paclitaxel 200 mg/m(2) by 1-hour intravenous (IV) infusion on day 1 and gemcitabine 1,000 mg/m(2) IV on days 1, 8, and 15; courses were repeated every 21 days. Patients who had objective response or stable disease continued treatment for six courses.

RESULTS

Twenty-nine of 54 patients (54%; 95% confidence interval, 40% to 67%) had major responses to treatment, including 7% complete responses. With a median follow-up of 24 months, 16 patients (30%) remain alive and nine (17%) are progression-free. The median survival for the entire group was 14.4 months; 1- and 2-year actuarial survival rates were 57% and 25%, respectively. Seven (47%) of 15 patients previously treated with platinum-based chemotherapy responded to paclitaxel/gemcitabine. Grade 3/4 toxicity was primarily hematologic, including leukopenia (46%), thrombocytopenia (13%), and anemia (28%). Ten patients (19%) required hospitalization for neutropenia and fever, and one patient had treatment-related septic death.

CONCLUSION

The combination of paclitaxel and gemcitabine is active and well tolerated in the first- or second-line treatment of patients with advanced transitional-cell carcinoma of the urothelial tract. Response rate and duration compare favorably with those produced by other active, first-line regimens. This regimen should be further evaluated in phase II and III studies, as well as in patients with compromised renal function.

CEO perceptions of competition--and strategic response in hospital markets

Physician-organization integration (POI) has emerged as a key issue for hospitals and health systems seeking to improve the quality and cost-effectiveness of care. Although competition and managed care are often cited as primary market drivers of the adoption of POI strategies, prior research has shown only weak associations between these market attributes and POI. This article argues that the role of key organizational decision makers has not been adequately accounted for in explaining strategic change. The study examines the role of hospital CEO perceptions of competition in predicting the adoption of five different approaches to POI. CEO perceptions of general market competition are explained by a combination of market and organizational attributes. Furthermore, when controlling for objective characteristics of the environment and organization, CEO perceptions of competition have consistent, statistically significant associations with four of five measures of POI examined.

The use of Medicaid claims as a supplementary source of information on quality of asthma care

This study examines the correspondence between medical records and Medicaid claims to determine whether claims are a valid source of data for monitoring quality of asthma care. A total of 460 claims for care encounters were matched to medical records of the encounters. While most of the diagnoses and procedures recorded on the claims were documented in medical records, claims failed to identify 29% of encounters with asthma diagnoses and 45% of nebulization procedures administered during encounters. About 30% of documented asthma prescriptions were not associated with filed claims, and about 30% of filed claims for asthma medication were not documented in medical records.

Vibrio cholerae O139 conjugate vaccines: synthesis and immunogenicity of V. cholerae O139 capsular polysaccharide conjugates with recombinant diphtheria toxin mutant in mice

Epidemiologic and experimental data provide evidence that a critical level of serum immunoglobulin G (IgG) antibodies to the surface polysaccharide of Vibrio cholerae O1 (lipopolysaccharide) and of Vibrio cholerae O139 (capsular polysaccharide [CPS]) is associated with immunity to the homologous pathogen. The immunogenicity of polysaccharides, especially in infants, may be enhanced by their covalent attachment to proteins (conjugates). Two synthetic schemes, involving 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and 1-cyano-4-dimethylaminopyridinium tetrafluoroborate (CDAP) as activating agents, were adapted to prepare four conjugates of V. cholerae O139 CPS with the recombinant diphtheria toxin mutant, CRMH21G. Adipic acid dihydrazide was used as a linker. When injected subcutaneously into young outbred mice by a clinically relevant dose and schedule, these conjugates elicited serum CPS antibodies of the IgG and IgM classes with vibriocidal activity to strains of capsulated V. cholerae O139. Treatment of these sera with 2-mercaptoethanol (2-ME) reduced, but did not eliminate, their vibriocidal activity. These results indicate that the conjugates elicited IgG with vibriocidal activity. Conjugates also elicited high levels of serum diphtheria toxin IgG. Convalescent sera from 20 cholera patients infected with V. cholerae O139 had vibriocidal titers ranging from 100 to 3,200: absorption with the CPS reduced the vibriocidal titer of all sera to < or =50. Treatment with 2-ME reduced the titers of 17 of 20 patients to < or =50. These data show that, like infection with V. cholerae O1, infection with V. cholerae O139 induces vibriocidal antibodies specific to the surface polysaccharide of this bacterium (CPS) that are mostly of IgM class. Based on these data, clinical trials with the V. cholerae O139 CPS conjugates with recombinant diphtheria toxin are planned.

Alcohol problems among a community sample: longitudinal influences of stress, coping, and gender

This study examined the relationships among stress, coping methods, and alcohol-use associated problems within a longitudinal, community sample of males and females who were followed from adolescence through young adulthood. While fewer females than males were categorized as "dependent users," these females were more debilitated in terms of the number of alcohol-related problems experienced from age 15 through age 25. Measures of both chronic and proximal levels of personal stress and negative coping styles were most helpful in explaining problems with alcohol use. Distal measures of stress and coping, while perhaps serving as mediators or moderators of other important constructs, did not appear to have a direct effect on the outcome measure.

An elementary school-based health clinic: can it reduce medicaid costs?

OBJECTIVE

School-based health services have evolved from primarily controlling communicable disease to comprehensive programs with direct services, education, and improvement of the school environment. School-based health clinics (SBHCs), currently 1157 in number, are used to reach children for preventive and other routine care. Although several studies have examined the costs and effects of such programs, few, if any, have examined their potential to save Medicaid program outlays. The objective of this study was to assess the effect of the Whitefoord Elementary School-Based Health Clinic (WESBHC), located in Atlanta, Georgia, on health care costs paid by Georgia Medicaid over the 1994-1996 period. This clinic has been in operation since late 1994.

DESIGN

The analysis uses 1994-1996 claims data for Medicaid-enrolled children 4 through 12 years old served by the WESBHC and similar children in a comparison school district without such a clinic. Descriptive and multivariate analyses are used to discern the differences in the changes in Medicaid expenses per child-year enrolled for these 2 groups of children. Both those who only used the WESBHC sporadically and those for whom it was their medical home were identified for analysis.

RESULTS

The descriptive analysis shows that although there were no significant differences in the Medicaid expenses for the WESBHC and comparison children in 1994, before the operation of the WESBHC, by 1995, the WESBHC children had significantly lower emergency department expenses. In addition, they had higher Early Periodic Screening Diagnosis and Treatment preventive care expenses. By 1996, the WESBHC children had significantly lower inpatient, nonemergency department transportation, drug, and emergency department Medi- caid expenses. Multivariate analysis confirmed the effect of the WESBHC on lowering emergency department expenses.

CONCLUSIONS

The results strongly suggest that the operation of a SBHC can have effects on the child's use of services and health care expenses. Given that these clinics serve all those who come for care and many of these are low-income children, these savings are likely to accrue to the Medicaid program of the state. As states continue to implement Medicaid-managed care for their child populations, they will need to consider the ability of SBHCs to participate in and receive Medicaid revenues through health maintenance organization networks.

Relationship between a self-reported health questionnaire and laboratory tests at initial office visits

BACKGROUND

Dental patients routinely complete a medical questionnaire and have an oral interview during their initial visit, but may have undiagnosed systemic problems which can affect their dental treatment.

METHODS

Thirty-nine consecutive patients referred for a periodontal evaluation completed a medical questionnaire and an oral interview. They were referred to a hospital laboratory for an urinalysis, complete blood count, and a standard blood chemistry panel.

RESULTS

The self-reported medical history responses were compared with the laboratory data and several abnormalities were noted. Abnormal levels were found with cholesterol, (26/39 patients, 67%); triglycerides, (13/39, 33%); glucose, (6/39, 15%); eosinophils, (18/39, 46%); and monocytes, (10/39, 26%). Smokers (17/39, 44%) had a higher number of abnormal levels or percentages of cholesterol, triglycerides, basophils, lymphocytes, eosinophils, and monocytes. Gender differences were seen in elevated triglyceride levels, abnormal aspartate aminotransferase (AST) and alanine aminotransferase (ALT), and self-reported cardiovascular disease.

CONCLUSIONS

This study demonstrated that many patients are unaware of their current medical status and a significant number had undiagnosed abnormalities.