Doctors' perspectives on the viability of rural practice

INTRODUCTION

Private practitioners play a vital role in meeting the health needs of rural communities. However, the prospect of operating a private practice business in rural Australia seems to be increasingly unattractive, because many communities are forced to recruit salaried or overseas-trained doctors. This study focuses on rural practices as businesses whose viability influences their attractiveness for the recruitment and retention of practitioners. The specific objectives are to ascertain which factors contribute to or threaten practice viability in rural areas, and whether they vary according to the degree of rurality or geographical remoteness.

METHODS

This study is based on data collected from a national study into the viability of rural general practice undertaken jointly by the Rural Doctors Association of Australia and Monash University School of Rural Health Bendigo. The Rural Remote and Metropolitan Area (RRMA) classification was used as the indicator of rurality. The study surveyed all general practitioners practising in rural or remote regions of Australia (RRMAs 3 to 7). Only practitioners with some financial interest in the practice were selected for this analysis. Free-text responses to the two questions 'What are the key factors contributing to the viability of your practice?' and 'What factors would put the viability of your practice at risk?' were analysed using qualitative content analysis. Factors were derived iteratively through higher-level aggregation of responses. Chi-square tests were used to make comparisons across the RRMA categories.

RESULTS

The national survey achieved a response rate of 35% of the entire population of GPs practising in RRMA 3 to 7 regions. Of these, 1050 respondents were relevant to this analysis. Seven major factors were identified by practitioners as the main contributors to practice viability. 'Practice characteristics' was nominated by 59% of respondents, followed by 'Income' (31%), 'Personal circumstances', 'Workforce' and 'Community characteristics' (all approximately 23%), 'GP activities and workload' (16%) and 'Professional support' (12%). Eight main factors were identified by practitioners as threats to viability. 'Workforce' was nominated by 57% of respondents, followed by 'Financial' (44%), 'Medico-legal' (33%), 'Administration-political' (16%), 'Community characteristics' (15%), 'GP-practice characteristics' and 'Personal circumstances' (10%) and 'Family circumstances' (3%). Across RRMA 3 to 5 the order of the percentage of respondents identifying each factor was generally consistent, with significant differences in the magnitude of the percentages for three contributing factors and four risk factors. While respondent numbers in RRMA 6 and 7 communities were low, significance testing did reveal differences between them and the rural communities on two contributing and one risk factor.

CONCLUSIONS

Practice viability is a major factor affecting the attractiveness of rural and remote practice for intending and existing GPs. Initiatives designed to contribute to viability will not be successful unless measures are also adopted to address perceived threats. This study highlights the systemic nature of the factors which contribute to and threaten practice viability. Although a primary component of practice viability is economic, with income from consultations being critical, the importance of the interrelationships between the main viability factors should not be underestimated. Clearly a multifaceted systemic response is required to overcome problems associated with rural workforce recruitment of future and burnout of current rural GPs.

Too hot to trot? exploring potential links between climate change, physical activity and health

Based on an analysis of existing literature, this paper explores the links between climate change, physical activity and health. It highlights the importance of physical activity for health, explores current understandings of factors influencing participation in sport and physical activity, and develops some hypotheses about the ways in which climate change may impact on the factors influencing physical activity and thereby on the level of participation in physical activity. The paper argues that climate change has the potential to be a barrier to participation in physical activity, particularly in areas where temperatures are already relatively high, and that a reduction in physical activity across the population is likely to have detrimental health impacts. The need for research to clarify the nature and extent of the threat posed to physical activity participation is highlighted, as is the need to take into account the direct and indirect costs of any changes or reductions in physical activity in any assessment of the costs of climate change and/or its mitigation.

Overlap between genitourinary medicine and public health in the surveillance and control of sexually transmitted infection in England, Wales and Northern Ireland

The control of sexually transmitted infections (STI), and in particular outbreaks and other acute incidents of STI, often requires resources outside the genitourinary medicine (GUM) clinic. This study of Consultants in Communicable Disease Control (CsCDC) in England, Wales and Northern Ireland, explored the level of collaboration between district public health departments and GUM clinics and the usefulness at local level of STI surveillance data. The results show an inconsistent working relationship between GUM and public health throughout the country and highlight deficiencies in current surveillance systems. Participants in the survey suggested potential remedies to the problems identified including enhanced surveillance of STI and formalised relationships between GUM and local public health departments. Enactment of these suggested remedies may contribute to meeting the challenge of reversing current disease trends.

An outbreak of serious illness and death among injecting drug users in England during 2000

An outbreak of serious illness and death occurred in injecting drug users during 2000 in Scotland, Ireland and England. National and international collaboration was necessary for the investigation and management of this outbreak. In England and Wales active case-finding was initiated, coupled with standardised data collection and microbiological investigation of cases. Twenty-six definite or probable cases were identified in England between 1 April and 31 Aug. 2000; 17 of these occurred in the North. The overall case fatality was 50% (13/26). The principal apparent risk factor was a history of intramuscular or subcutaneous injection of heroin and the limited duration of the outbreak suggested that the problem might have been related to a particular supply of heroin. Clostridium novyi was isolated from two English cases. Taken in conjunction with contemporaneous microbiological and epidemiological results from Scottish and Irish cases, the probable aetiology for this outbreak was infection with C. novyi associated with both a particular supply of heroin and the method of preparation and injection used. A 'toolkit' was distributed in Sept. 2000 to all Consultants for Communicable Disease Control in England and Wales to assist them with the ongoing surveillance, investigation and management of this condition. Lessons learned have been used to produce guidance for the investigation and management of outbreaks of unexplained serious illness of possible infective aetiology.

Uncertainties on predicted concentrations of radionuclides in terrestrial foods and ingestion doses

Models are routinely used to calculate doses following routine releases and potential accidental releases of radionuclides. These models contain a number of parameters. Values for many of these are not accurately known. The primary aim of this study was to determine the level of uncertainty on predicted concentrations of radionuclides in foods, and doses to individuals consuming those foods, arising from uncertainties on the model input parameter values. A secondary objective was to identify those input parameters whose uncertainty makes a major contribution to the overall uncertainty on the predicted endpoints. The methodology adopted and results obtained are presented for the following radionuclides: 90Sr, 131I, 137Cs and 239Pu. The estimated uncertainty ratios (the ratio of the 95th to the 5th percentile) are frequently very large, often two to three orders of magnitude. The results of this study may be used to identify areas where further research could improve assessment capabilities.

Is negative affectivity associated with oral quality of life?

OBJECTIVES

The personality trait of negative affectivity (NA) is associated with reports of worse physical health, more symptoms and worse health-related quality of life but its associations with oral quality of life (OQOL) are unexplored. In this study we examined the association of NA with OQOL.

METHODS

We drew on data from two samples of older men: The VA Dental Longitudinal Study (DLS; n=177) and the Veterans Health Study (VHS; n=514), which included three measures of oral quality of life: the Oral Health-Related Quality of Life Measure (OHQOL), the Oral Health Impact Profile (OHIP), and the Geriatric Oral Health Assessment Instrument (GOHAI). For each OQOL measure, and the GOHAI and OHIP subscales, two regression models were estimated to examine the marginal change in variance due to NA: the first model included age, number of teeth, and self-rated oral health, and the second added NA.

RESULTS

In both bivariate and multivariate analyses, higher NA was consistently associated with worse scores on the OQOL measures. In the regression analyses, NA explained an additional.01 to 18% of the variance in OQOL, explaining the most variance in the OHIP and the least in the OHQOL. The addition of NA explained more variance in the more subjective, psychologically oriented GOHAI and OHIP subscales than it did in the more objective, physical function oriented subscales.

CONCLUSIONS

Psychosocial factors such as personality are significantly associated with quality of life ratings. Such associations should be taken into account when OQOL measurements are used and interpreted.

Neuroprotective efficacy of AR-A008055, a clomethiazole analogue, in a global model of acute ischaemic stroke and its effect on ischaemia-induced glutamate and GABA efflux in vitro

We have investigated the neuroprotective properties of AR-A008055 [(+/-)-1-(4-methyl-5-thiazolyl-1-phenyl-methylamine], a novel compound structurally related to clomethiazole. Administration (i.p.) of (+/-)-AR-A008055 60 min after 5 min of global cerebral ischaemia in gerbils produced a dose-dependent protection of the hippocampus from damage. Both enantiomers [(R)-(+)-AR-A008055 and (S)-(-)- AR-A008055] at 600 micromol/kg produced similar protection to that following clomethiazole (600& micromol/kg) and both produced similar and sustained neuroprotection, at 4, 7 and 21 days post-insult. When infused intravenously over a 2-h period, both enantiomers produced concentration-dependent neuroprotection, with the enantiomers providing similar protection at every plasma concentration (50-200 nmol/ml). The efficacy of (S)-(-)-AR-A008055 was similar to clomethiazole, but it was slightly less potent. Ischaemia-induced glutamate efflux from rat brain cortical prisms in vitro was inhibited by both isomers (100 microM). The inhibitory effect of (R)-(+)-AR-A008055 was blocked by bicuculline (10 microM) and picrotoxin (100 microM), while the effect of (S)-(-)-AR-A008055 was only antagonised by picrotoxin. This indicated that (S)-(-)-AR-A008055, like clomethiazole, is able to open the GABA(A)-chloride channel in the absence of endogenous GABA. (R)-(+)-AR-A008055 was more potent than (S)-(-)-AR-A008055 in enhancing the concentration of GABA in the medium following 30 min exposure of tissue to the ischaemic conditions, suggesting that it is an effective GABA uptake inhibitor. This action may explain both its effect on glutamate efflux in vitro and its neuroprotective effect in vivo.

A phase II study of high dose tamoxifen and weekly cisplatin in patients with metastatic melanoma

We have previously demonstrated that the combination of tamoxifen and cisplatin has activity in patients with metastatic melanoma. In vitro studies have demonstrated that tamoxifen and cisplatin exhibit cytotoxic synergy in human melanoma cells and that this interaction is dependent on a tamoxifen effect. The mechanism of this effect is currently under investigation in in vitro studies. In an attempt to improve the complete response rate of this regimen, we initiated a phase II trial to determine the effect of the use of high dose tamoxifen and weekly cisplatin on the complete response rate, disease-free survival and overall survival. Tamoxifen was started on day 1 initially at a dose of 240 mg/day and continued until the patient was taken off treatment. This dose was subsequently lowered to 200 mg/day. Cisplatin (80 mg/m2) was begun on day 2 and repeated weekly for a total of 3 weeks. During week 4, the patient was not treated with cisplatin but was evaluated for response. If disease stabilization or regression was documented, the patient received a second 3 week cycle of cisplatin and was then re-evaluated for response. Patients with progressive disease at any evaluation were removed from the study. In 28 consecutive patients, the overall response rate was 32% (95% confidence interval 15.88-52.35%). One patient achieved a complete remission that lasted 22 months. All other responses were partial in nature. Toxicity was primarily nausea and vomiting. Two patients developed grade 2 renal toxicity. There were no episodes of deep venous thrombosis. This phase II study demonstrates that this combination has modest activity in patients with metastatic melanoma. However, this study failed to confirm our hypothesis that high dose tamoxifen would increase the complete response rate of this combination. While this combination has activity, the overall response rate is not significantly better that that observed with the original Dartmouth regimen and the toxicity is substantial. We do not recommend this dose and schedule for routine clinical use.

Today's dental student is training for tomorrow's elderly baby boomer

We are constantly reminded of the exploding elderly population and the increasing demand to meet their needs. But do we fully understand and appreciate the impact that this fastest-growing segment of the population will have upon our profession? Whether we realize it or not, today's dental student is training for tomorrow's elderly baby boomer. The baby boomer generation is 76 million strong, representing 19 years worth of births spanning from 1946-1964. That makes the oldest baby boomer 55 years old and the youngest 37 years old. What does this all mean? That from 2011-2030, the age group of 65 years of age and older will make up approximately 22% of the population, vastly changing our patient population, not to mention a significant increase in patient load. The future holds promise for not only a busy career, but also potentially a financially rewarding one as well. To some extent, we are all going to be geriatric clinicians. There is little doubt that there will be a great demand for services in restorative dentistry, prosthodontic dentistry, endodontics, periodontics, oral surgery, and perhaps orthodontics. As the baby boomers benefited from fluoride and sanitation, more people have been able to maintain their dentition and health into their older years. Dental students graduating today will be only beginning the prime of their careers as the baby boomers make their introduction in full force in the year 2011.

SALSA: a pattern recognition algorithm to detect electrophile-adducted peptides by automated evaluation of CID spectra in LC-MS-MS analyses

A pattern recognition algorithm called SALSA (scoring algorithm for spectral analysis) has been developed to rapidly screen large numbers of peptide MS-MS spectra for fragmentation characteristics indicative of specific peptide modifications. The algorithm facilitates sensitive and specific detection of modified peptides at low abundance in an enzymatic protein digest. SALSA can simultaneously score multiple user-specified search criteria, including product ions, neutral losses, charged losses, and ion pairs that are diagnostic of specific peptide modifications. Application of SALSA to the detection of peptide adducts of the electrophiles dehydromonocrotaline, benzoquinone, and iodoacetic acid permitted their detection in a complex tryptic peptide digest mixture. SALSA provides superior detection of adducted peptides compared to conventional tandem MS precursor ion or neutral loss scans.

Target outcomes for long-term oral health care in dementia: a Delphi approach

This study developed a list of target outcomes for long-term oral health care in persons with dementia. A three-round Delphi study was used to develop a list of target outcomes. Participants included 99 staff and 171 family members associated with the Dementia Special Care Unit in Bedford, MA. In Round 1 participants were asked to list five outcomes for long-term oral health care. Items were grouped, redundancies removed, and fed back in Round 2, when participants scored the items from 1 (least important) to 10 (most important). Round 2 responses were tabulated and the top 20 were fed back for scoring in Round 3. The top 10 target outcomes in decreasing order of importance were: patient will be free from oral pain, patient will not be at risk for aspiration, emergency dental treatment will be available when needed, prevent mouth infections, daily mouth care is as much a part of daily care as shaving or brushing hair, prevent discomfort from loose teeth or sore gums, teeth will be brushed thoroughly once a day, staff will be able to provide oral hygiene care as needed, provide dental care to prevent problems eating, and recognize oral problems early. Family and professional caregivers were remarkably consistent in their identification of the top 10 outcomes. Further work is needed to ensure broad international and interdisciplinary acceptance (including families and the long-term care residents themselves) of target outcomes for long-term oral health care in persons with dementia.

The feasibility and efficacy of tobacco use prevention in orthodontics

SMILES PLUS was the first study to extend the clinician-delivered logic model to prevention of tobacco use among adolescents. This multi-site trial with 154 participating offices, based on social learning theory and a behavioral ecological model, was designed to test whether orthodontists can prevent preteens from initiating smoking. The study found that orthodontists do not automatically adhere to anti-tobacco prevention services. Social learning variables can enhance both adherence to counseling guidelines and content of counseling to increase prevention effects. Providing financial incentives, tracking prescriptions, prompting positive feedback from patients, and adopting anti-tobacco counseling models in the office are likely to enhance anti-tobacco preventive services. Training orthodontists to be comfortable when advising nonsmoking youth not to start and to use social consequences to justify youth avoidance of tobacco might increase adherence to protocols and make their counseling more powerful. Adolescent smokers prior to intervention were more likely to start other risky behaviors later. Preventing tobacco use may halt additional risk behaviors and thereby reduce morbidity/mortality even more than expected from tobacco control alone. New and refined clinical trials should be conducted to determine the most effective interventions for adolescent tobacco control by clinicians.

A phase II trial of estramustine and etoposide in hormone refractory prostate cancer: A Southwest Oncology Group trial (SWOG 9407)

BACKGROUND

The combination of oral estramustine and oral etoposide has generated response rates of 40-50% in patients with hormone refractory prostate cancer in single institution trials. This study tested this regimen in a multi-institutional setting.

METHODS

Fifty-five patients were accrued over a period of 4 months between 1 March 1996 and 1 July 1996. Two patients were not analyzable and two patients were ineligible. They were given an oral regimen consisting of estramustine 15 mg/kg/day (capped at 1120 mg per day) and etoposide 50 mg/M(2)/day, days 1-21 every 28 days. Patients received a median of two cycles of therapy.

RESULTS

Toxicities included 11 patients (20%) with grades 3 or 4 granulocytopenia, 5 patients (10%) with grades 3 or 4 edema, and 3 patients (6%) with a thrombotic event. There were two treatment-related deaths, one as a result of anemia and the other as a result of a myocardial infarction. Of the 32 men who received at least 2 cycles of therapy, 7 men (22%) demonstrated a partial response to this regimen as measured by prostate-specific antigen (PSA) criteria of a 50% decline from pretreatment values.

CONCLUSIONS

This trial demonstrates the toxicity of estramustine delivered in high dose. It also illustrates the difficulty of conducting phase II trials in prostate cancer in the cooperative group setting where the experience and comfort level of oncologists with new agents is less than that of the physicians at the institution where the therapy was developed. As the activity of this regimen with low-dose estramustine is defined, further multi-institutional studies may be warranted.

Response of native and denatured hen lysozyme to high pressure studied by (15)N/(1)H NMR spectroscopy

High-pressure (15)N/(1)H NMR techniques were used to characterize the conformational fluctuations of hen lysozyme, in its native state and when denatured in 8 M urea, over the pressure range 30--2000 bar. Most (1)H and (15)N signals of native lysozyme show reversible shifts to low field with increasing pressure, the average pressure shifts being 0.069 +/- 0.101 p.p.m. ((1)H) and 0.51 +/- 0.36 p.p.m. ((15)N). The shifts indicate that the hydrogen bonds formed to carbonyl groups or water molecules by the backbone amides are, on average, shortened by approximately 0.02 A as a result of pressure. In native lysozyme, six residues in the beta domain or at the alpha/beta domain interface have anomalously large nonlinear (15)N and (1)H chemical-shift changes. All these residues lie close to water-containing cavities, suggesting that there are conformational changes involving these cavities, or the water molecules within them, at high pressure. The pressure-induced (1)H and (15)N shifts for lysozyme denatured in 8 M urea are much more uniform than those for native lysozyme, with average backbone amide shifts of 0.081 +/- 0.029 p.p.m. ((1)H) and 0.57 +/- 0.14 p.p.m. ((15)N). The results show that overall there are no significant variations in the local conformational properties of denatured lysozyme with pressure, although larger shifts in the vicinity of a persistent hydrophobic cluster indicate that interactions in this part of the sequence may rearrange. NMR diffusion measurements demonstrate that the effective hydrodynamic radius of denatured lysozyme, and hence the global properties of the denatured ensemble, do not change detectably at high pressure.

Recombinant factor IX (BeneFix) by adjusted continuous infusion: a study of stability, sterility and clinical experience

The safety and efficacy of adjusted continuous infusion (CI) of recombinant factor IX (FIX; BeneFix) was assessed in vitro and in a clinical study. BeneFix was reconstituted at 100 IU mL-1 with or without unfractionated heparin (4 U mL-1) and stored at either 4 degrees C or room temperature. Reconstituted BeneFix retained at least 90% activity over 14 days if stored at 4 degrees C but stability was reduced at room temperature. BeneFix reconstituted in a sterile pharmacy was free of bacterial contamination. Six patients with haemophilia B received seven CIs of BeneFix to cover routine surgery and severe bleeding episodes. The CIs lasted between 3 and 10 days. In all cases, haemostasis was excellent and the desired therapeutic FIX level was easily maintained. No thrombotic episodes or inhibitor development occurred but two patients developed thrombophlebitis at the infusion site when heparin was not added to the infusion. BeneFix is not currently licensed for CI and we suggest that studies to enable licensing should be established as soon as possible.

Resonance offset tailored composite pulses

We describe novel composite pulse sequences which act as general rotors and thus are particularly suitable for nuclear magnetic resonance quantum computation. The resonance offset tailoring to enhance nutations approach permits perfect compensation of off-resonance errors at two selected frequencies placed symmetrically around the frequency of the radiofrequency source.

Oral health of ambulatory care patients

OBJECTIVES

This project assessed the clinical oral health status of Veterans Administration (VA) patients and examined the relationship between oral health and both sociodemographic factors and dental care utilization.

METHODS

Data were collected on 538 users of VA ambulatory medical care. Oral health was assessed by clinical examinations, and dental use and sociodemographic information are based on self-report.

RESULTS

Younger, more educated VA patients with higher incomes had more teeth, fewer untreated and treated root caries, and were less likely to be edentulous or to have dentures. Dental utilization emerged as the most important aspect of veterans' oral health status, even after sociodemographic factors were controlled. Compared with the general population, veterans have poorer oral health with the exception of coronal caries.

CONCLUSION

Compared with national studies, VA patients appear to have worse oral health. The importance of sociodemographic factors and dental utilization that has been found in other studies applies to veterans' oral health as well.

Heart murmurs: are older male dental patients aware of their existence?

BACKGROUND

The American Heart Association recommends that patients with certain abnormal and prosthetic heart valves receive antibiotic prophylaxis before undergoing invasive dental treatment, owing to the risk of bacterial endocarditis, or BE. However, it is not known how many patients are aware that they have such conditions and understand such recommendations.

METHODS

The authors conducted a study to determine how many male users of three U.S. Department of Veterans' Affairs ambulatory medical care centers denied having a heart murmur, even though a murmur was noted in their medical record. The authors asked 637 potential subjects a series of questions to identify those who had a heart murmur that might place them at risk of developing BE. The authors then reviewed each subject's medical records for documentation of a heart murmur.

RESULTS

Four hundred ninety-seven dentate men (mean age: 61.0 years) denied having a heart murmur. Seventy (14.1 percent) of these men had documentation of a heart murmur in their medical records, and 13 (2.6 percent) had murmurs that were likely to be pathological. The failure to accurately report having a heart murmur and having a potentially pathological heart murmur were positively related to age (P = .001). Failure to accurately report having a heart murmur also was related to lower educational levels.

CONCLUSIONS

These results indicate that a substantially larger number of older men than younger men were unaware that they had a heart murmur. Since some of these murmurs necessitate administration of antibiotic prophylaxis before dental procedures, this failure to communicate their correct medical status may put them at risk of developing BE.

CLINICAL IMPLICATIONS

Dental health care providers should be aware that patient self-report may not be a reliable indicator of cardiac status, particularly in older patients.

Self-reported and clinical oral health in users of VA health care

BACKGROUND

This article describes the oral health of users of Veterans Administration (VA) health care using both clinical and self-report measures, and models relationships between these measures and self-perceived oral health.

METHODS

We conducted a cross-sectional study of 538 male users of VA outpatient care in the Boston area. Questionnaires assessed self-reported oral health, oral-specific health-related quality of life, health behaviors, and sociodemographic information. Clinical data were collected on oral mucosa status, number of teeth and root tips, dental caries, and periodontal treatment need. We report clinical and self-reported oral health status by age group (era of military service). We regressed models of self-perceived oral health on clinical indices and self-reported measures of the impact of oral health on daily life, adjusting for sociodemographic characteristics and health behavior.

RESULTS

Among those participants aged 65 to 91 years old, 2.8%, 18.7%, and 41.5% rated their oral health as excellent, very good, or good, respectively. Among 50- to 64-year-old men, the corresponding values were 1.4%, 18.5%, and 40.4%, while among those aged 22 to 49 years old, the values were 2.3%, 17%, and 34.1%. Tooth loss was common among users of VA care; 34% of those aged 65-90 years, 28% of those aged 50-64 years, and 8% of those aged 25-49 years had no teeth. Periodontal treatment needs were uniformly high among persons with teeth; mild mucosal change was common, and 10% had root tips. Regression models showed self-perceived oral health was better in persons with more teeth and recent dental treatment, and worse with tooth mobility, coronal decay, and more medical problems. Measures of the impact of oral conditions on daily life added significantly to the amount of explained variance in self-perceived oral health.

CONCLUSIONS

Clinical conditions and the impact of oral health on daily life are important determinants of self-perceived oral health.

Increasing asthma knowledge and changing home environments for Latino families with asthmatic children

We tested an asthma education program in 204 underserved Latino families with an asthmatic child. The education program consisted of one or two sessions delivered in each family's home in the targeted participant's preferred language by a bilingual, bicultural educator. We encouraged, but did not require, attendance by the child. The curriculum was culturally-tailored, and all participants received education on understanding asthma, preventing asthma attacks, and managing asthma. Outcomes included change in asthma knowledge and change in home environment asthma management procedures. Asthma knowledge increased significantly (39 to 50% correct from pre- to post-test, P < 0.001) and participants made significant changes to the child's bedroom environment (mean number of triggers decreased from 2.4 to 1.8, P < 0.001; mean number of controllers increased from 0.7 to 0.9, P < 0.001). The results support the value of asthma education and its importance in the national agenda to reduce health disparities among minorities.

Tandem MS analysis of model peptide adducts from reactive metabolites of the hepatotoxin 1,1-dichloroethylene

Dichloroethylene (DCE) is a hepatotoxin that undergoes cytochrome P450-catalyzed bioactivation in hepatocytes to form 2-chloroacetyl chloride and 1,1-dichloroethylene oxide. 2-Chloroacetyl chloride reacts with nucleophilic residues and with N-terminal amines to produce 2-chloroacetylated residues and with glutathione to form the reactive electrophile S-(2-chloroacetyl)glutathione (ClCH(2)COSG), which, in turn, is capable of sulfhydryl alkylation. 1,1-DCE oxide can bind to cysteine sulfhydryl groups and subsequently hydrolyze to form an S-carboxymethylated cysteine residue. S-Carboxymethylated, 2-chloroacetylated, and GSCOCH(2)-S-Cys-peptide adducts of model cysteine-containing peptides were synthesized, and their fragmentation patterns were characterized by electrospray tandem mass spectrometry. Synthesis of GSCOCH(2)-S-Cys-peptide adducts was achieved via a novel tert-butoxycarbonyl (tBOC) derivative of ClCH(2)COSG. CID of GSCOCH(2)-S-Cys-peptide adducts resulted in product ions and neutral losses indicative of the GSCOCH(2)-S-Cys moiety as well fragment ion pairs in the b- and y-ion series corresponding to the modified cysteine residue. S-Carboxymethylated peptides exhibited only a characteristic b- or y-series ion pair separated by 161 Da, corresponding to cysteine + CH(2)COOH. CID of 2-chloroacetylated peptides showed neutral losses of 36 (HCl), 78 (HCOCH(2)Cl), 96 (HCOCH(2)Cl + H(2)O), and 114 Da (HCOCH(2)Cl + 2H(2)O). Combinations of characteristic fragment ions, neutral losses, and ion pairs thus are characteristic for DCE-derived adducts. These features can be used in an MS/MS data reduction algorithm for the selective identification of protein targets of DCE metabolites.

New method to improve treatment outcomes for radical prostatectomy

Modifications in radical retropubic prostatectomy that use the deep dorsal vein ligator and either anterior urethropexy or puboprostatic ligament preservation were developed to reduce blood loss and improve continence results. Use of the deep dorsal vein ligator to secure the deep dorsal vein complex also improves visualization of the urethra for transection and the neurovascular bundle for nerve sparing and thereby may assist in laparoscopic radical retropubic prostatectomy.

Perceptual calibration of F0 production: evidence from feedback perturbation

Hearing one's own speech is important for language learning and maintenance of accurate articulation. For example, people with postlinguistically acquired deafness often show a gradual deterioration of many aspects of speech production. In this manuscript, data are presented that address the role played by acoustic feedback in the control of voice fundamental frequency (F0). Eighteen subjects produced vowels under a control (normal F0 feedback) and two experimental conditions: F0 shifted up and F0 shifted down. In each experimental condition subjects produced vowels during a training period in which their F0 was slowly shifted without their awareness. Following this exposure to transformed F0, their acoustic feedback was returned to normal. Two effects were observed. Subjects compensated for the change in F0 and showed negative aftereffects. When F0 feedback was returned to normal, the subjects modified their produced F0 in the opposite direction to the shift. The results suggest that fundamental frequency is controlled using auditory feedback and with reference to an internal pitch representation. This is consistent with current work on internal models of speech motor control.

Synthetic spider silk: a modular fiber

Spiders make their webs and perform a wide range of tasks with up to seven different types of silk fiber. These different fibers allow a comparison of structure with function, because each silk has distinct mechanical properties and is composed of peptide modules that confer those properties. By using genetic engineering to mix the modules in specific proportions, proteins with defined strength and elasticity can be designed, which have many potential medical and engineering uses.