Regulation of fibroblast-induced collagen gel contraction by interleukin-1beta

Fibroblasts incorporated within collagen gels induce a cell-mediated contraction of the gel to form a three-dimensional, tissue-like structure by a mechanism thought to mimic wound contraction in vivo. In this study a gel contraction model was used to investigate the ability of fibroblasts derived from adult gingiva, adult skin and fetal skin to organise a collagen matrix. In addition the effects of interleukin-1beta (IL-1beta) on the contraction process was also investigated. Over the concentration range 5-50 U/ml, IL-1beta induced a statistically significant inhibition of gel contraction in all fibroblast cell types (P<0.05), although fetal fibroblasts appeared least responsive and gingival fibroblasts most responsive to the inhibitory effects of this cytokine. Comparison of gel contraction by the different fibroblast strains indicated that fetal and gingival fibroblasts shared similar contraction kinetics. For the adult skin fibroblasts, three of five strains studied showed significantly diminished levels of gel contraction compared to fetal and gingival cells. This apparent difference in fibroblast phenotype may, at least in part, explain the fetal-like wound healing pattern seen in the oral mucosa.

A comparison sample validation of "your workplace": an instrument to measure perceived alcohol support and consequences from the work environment

This paper addresses the psychometric properties of Your Workplace (YWP), an instrument developed to measure perceived influence of workplace norms and attitudes on alcohol involvement and the experience of adverse consequences. Data were collected from a large, geographically dispersed sample of aftercare and outpatients recruited for a multisite clinical trial of alcoholism treatments, Project MATCH. Administration of YWP at the baseline assessment was restricted to workforce participants. A confirmatory factor analysis addressed instrument structure. Internal consistency and concurrent association between measures of general social support, alcohol specific support, and alcohol involvement were examined. YWP scales were found to have adequate internal consistency reliability. Correlation between YWP scales and concurrent measures of alcohol involvement were among the strongest found. Identification of workplace influences on alcohol involvement allows refined assessment and fosters a comprehensive approach to treatment of alcoholism.

When 3-year-olds pass the appearance--reality test

Sixty-eight 3-year-olds received a standard appearance-reality task along with either a trick task, in which the appearance question was placed in the context of a deceptive game, or a reduced information processing task, in which a dual object (e.g., a sponge-rock) was presented along with an object that matched the dual object's identity (a sponge) and one that matched the dual object's appearance (a rock). Children were more likely to pass either the trick or reduced information processing task and fail the standard than the reverse. Thus, 3-year-olds can grasp the distinction between appearance and reality (a) when their goal is to trick someone, which may prime them to think about the other's mental state, and (b) when they do not need to held conflicting object identities in mind at the same time.

Investigation of nurse practitioner-patient interactions: using the Nurse Practitioner Rating Form

Primary care has become a major focus of health care reform. To create the most effective delivery of primary care services by nurse practitioners (NPs), researchers, clinicians, and administrators must continue to develop knowledge about the structure, process, and outcomes of NP primary care patient encounters. Few measures of NP-patient care encounters exist. This exploratory study examines a method of investigating NP practice and a description of the process of NP primary care. The Nurse Practitioner Rating Form (NPRF) was used to analyze 20 videotaped NP visits with Latino clients in a primary care setting. Major findings are that NPs spent visit time engaged in assessment (61%), management (29%), and charting, consultation, and other (10%). The content or focus of the majority of NP time during visits (90%) was directed to existing physical problems. NPs received high scores for communication style and degree of client participation. Problems with using the NPRF are noted and key recommendations are made to enhance NP care and improve investigation of primary care practice.

Secondary squamous cell carcinoma of the orbit

OBJECTIVE

To evaluate the origin and biological behavior of secondary orbital squamous cell (SCC) and mucoepidermoid carcinoma.

METHODS

A retrospective review of 30 consecutive patients with SCC and mucoepidermoid carcinoma of the orbit seen over a period of 8 years at a large ophthalmic hospital in Saudi Arabia.

RESULTS

A total of 51 secondary orbital tumors were seen in the 8-year period from 1983 through 1991; 30 (60%) of the 51 cases were SCC. There were 16 male and 14 female patients, with an age range of 38 to 80 years and a mean age of 65 years. In 28 (93%) of the 30 patients, the tumor originated in the conjunctiva. Orbital involvement by conjunctival SCC was the most common cause of secondary orbital tumors encountered in patients older than 19 years. Four patients had concomitant paranasal sinus involvement, 4 patients exhibited intraocular invasion, and 2 others were found to have intracranial extension of the SCC. Six (20%) of the 28 patients developed regional lymph node metastases during the course of their illness. All patients were treated by orbital exenteration, with or without radiation therapy. Seven (23%) of the 28 patients died of their disease.

CONCLUSIONS

Orbital SCC is an aggressive and life-threatening condition. Most cases result from secondary extension of conjunctival SCC, a common disease in Saudi Arabia. Several factors contribute to the aggressiveness of conjunctival SCC in this geographic location, including continual exposure to UV rays, chronic irritation, and genetic factors. Delay in presentation for treatment, inadequate initial resection of conjunctival lesions, and the aggressive mucoepidermoid carcinoma variant of SCC are also factors contributing to orbital invasion.

Benzo[a]pyrene coated ferric oxide and aluminum oxide particles: uptake, metabolism and DNA binding in hamster pulmonary alveolar macrophages and tracheal epithelial cells in vitro

Ferric oxide (Fe2O3) and aluminum oxide (Al2O3) particles are widely encountered in occupational settings. Benzo[a]pyrene (B[a]P), a well-characterized environmental carcinogen, is frequently adsorbed onto particles. It has been shown that B[a]P-coated Fe2O3 particles (B[a]P-Fe2O3) significantly increased lung tumors in the hamster in contrast to B[a]P-coated Al2O3 (B[a]P-Al2O3) or B[a]P alone. In order to determine the genotoxic effects of these particles on the metabolism of B[a]P, pulmonary alveolar macrophages (AM) from male Syrian golden hamsters were incubated with 5 microg (19.8 nmol) B[a]P-coated respirable size (99% < 5 microm) Fe2O3 and Al2O3 particles with loads from 0.5 to 2.0 mg. Intracellular uptake of B[a]P by AM at 24 h was higher with B[a]P-Fe2O3 than that of B[a]P alone (P < 0.05) or B[a]P-Al2O3 (P < 0.05). Total B[a]P metabolism was significantly greater in AM exposed to B[a]P-coated Fe2O3 at 1.0 and 1.5 mg than in the AM exposed to B[a]p-al2O3 (0.5, 1.0 and 1.5 mg) (P < 0.05) or B[a]P alone (P < 0.05). Similar significant differences for Fe2O3 relative to Al2O3 and B[a]P alone were also apparent for total dihydrodiols, quinones and phenolic metabolites. Co-administration of 5 microg alpha-naphthoflavone (alpha-NF, an inhibitor of cytochrome P-4501A1 and P-4501A2) and 10(-3) M cyclohexene oxide (CO, an inhibitor of epoxide hydrolase) significantly reduced B[a]P metabolism in B[a]P-Fe2O3 (P < 0.05) and B[a]P-Al2O3 (P < 0.05) treated groups relative to B[a]P alone. AM were co-cultured with hamster tracheal epithelial cells (HTE) and treated as described above for metabolism studies to assess the DNA binding of B[a]P metabolites in the target cells, using 32P-postlabeling techniques. Two adducts were observed that had chromatographic behavior similar to 7R,8S,9S-trihydroxy-10R-(N2-deoxyguanosyl-3'-phosphate)-7,8,9,10-t etrahydrobenzo[a]pyrene [(+)-anti-BPDE-dG, adduct 1, major adduct representing 70-80% of total adducts] and 7S,8R,9R-trihydroxy-10S-(N2-deoxyguanosyl-3'-phosphate)-7,8,9,10-t etrahydrobenzo[a]pyrene [(-)-anti-BPDE-dG, adduct 2, representing 20-30% of total adducts]. B[a]P-Fe2O3 treatment enhanced the levels of the two B[a]P-DNA adducts in the HTE compared with B[a]P-Al2O3 (P < 0.05) or B[a]P alone. The inhibitors alphaNF and CO significantly reduced total adduct levels in the HTE (P < 0.05) in the B[a]P and B[a]P-Fe2O3 treatments as well as adduct 1 and adduct 2 levels. Our data suggest that the cocarcinogenic effect of B[a]P-Fe2O3 relative to B[a]P-coated Al2O3 can be due to: (i) the enhancement of B[a]P metabolism in AM by Fe2O3 associated with the increased uptake of B[a]P; and (ii) augmentation of DNA adduct formation in epithelial cells.

When 3-year-olds pass the appearance--reality test

Sixty-eight 3-year-olds received a standard appearance-reality task along with either a trick task, in which the appearance question was placed in the context of a deceptive game, or a reduced information processing task, in which a dual object (e.g., a sponge-rock) was presented along with an object that matched the dual object's identity (a sponge) and one that matched the dual object's appearance (a rock). Children were more likely to pass either the trick or reduced information processing task and fail the standard than the reverse. Thus, 3-year-olds can grasp the distinction between appearance and reality (a) when their goal is to trick someone, which may prime them to think about the other's mental state, and (b) when they do not need to held conflicting object identities in mind at the same time.

Refractory ceramic fiber exposure and pleural plaques

Refractory ceramic fibers (RCF) are manmade vitreous fibers (MMVF) manufactured for high-temperature applications. Between 1987 and 1992, a retrospective cohort and nested case-control study evaluated chest radiographs from 652 workers involved in the manufacture of these fibers for plausibility of a causal relationship between exposure to RCF and chest-radiographic changes. The exposure-response relationship was modeled with three variables: years since first fiber production job, years in fiber production, and cumulative fiber exposure to date of study X-ray. The case-control study used a comprehensive characterization of possible asbestos exposure to investigate asbestos as the potential causative agent of chest-radiographic changes. Chest radiographs of 20 workers (3.1%) demonstrated 19 pleural plaques and one diffuse pleural thickening. Nine of 72 workers (12.5%) with more than 20 yr since their first fiber-production job had plaques (odds ratio [OR] = 9.5; 95% confidence interval [CI] = 1.9 to 48.2). Five of 19 workers with more than 20 yr in fiber-production work (26.3%) had plaques (OR = 22.3; 95% CI = 3.6 to 137.0). Similarly, adjusted ORs demonstrated a progressive relationship between cumulative fiber-months per milliliter (fiber-mo/ml) exposure and plaques. The case-control study confirmed that asbestos exposure did not account for the observed association between fiber exposure and plaques. A validity review of historical films demonstrated biologic plausibility for the association, since sufficient latency existed from the time of first RCF exposure to the development of plaques. There was no significant increase in parenchymal changes consistent with interstitial fibrosis.

Silicosis among foundry workers. Implication for the need to revise the OSHA standard

To evaluate the risk of pneumoconiosis among workers in a Midwestern automotive foundry, medical records and silica sand exposure data were analyzed for 1,072 current and retired employees with at least 5 years of employment as of June 1991. Approximately half of these employees had worked at the foundry for 20 or more years. Sixty workers were found to have radiographic evidence of pneumoconiosis. Twenty-eight workers had radiographs consistent with silicosis, of which 25 were consistent with simple silicosis and three with progressive massive fibrosis. The prevalence of radiographic changes consistent with silicosis increased with: number of years worked at the foundry (6% for 20-29 years and 12% for 30 or more years); cigarette smoking (12.2% among smokers with high silica exposure vs. 4.4% among never smokers with high silica exposure); work area within the foundry (cleaning room, core room, mold area, core knockout); and quantitative silica exposure (0.3-2.7% of workers at the current Occupational Safety and Health Administration (OSHA) standard and 4.9-9.9% of workers above the OSHA standard). In addition, the odds of developing radiographic changes consistent with silicosis were increased for African Americans (odds ratio = 2.14, 95% confidence interval 0.85-5.60) in comparison with whites. (The risk was similar when silica exposure was equal, but African-American workers on average had greater exposure to silica, despite having a similar duration of work as white workers.) Another eight workers had radiographic evidence of asbestosis, and 24 had pleural plaques. These asbestos-related changes were not associated with increasing exposure to silica but rather were associated with being in the maintenance department and performing repair work. After controlling for cigarette smoking, race, and exposure to silica at another job besides the foundry, the authors found a 1.45 increased risk of developing a radiograph consistent with silicosis after 20 years of work at the current OSHA standard, and a 2.10 increased risk after 40 years of work at the current OSHA standard. On the basis of these findings, the authors recommend maintaining silica air levels no higher than the exposure level of 0.05 mg/m3 recommended by the National Institute for Occupational Safety and Health.

Ovarian activity and vaginal bleeding patterns with a desogestrel-only preparation at three different doses

A randomized, double-blind, group-comparative study was performed over a 6 month period to compare ovarian suppression and vaginal bleeding during the use of three oral contraceptives containing doses of 30, 50 or 75 micrograms desogestrel. A total of 44 female volunteers with regular cycles and established ovulation by ultrasonography were recruited from an out-patient clinic in a university hospital and asked to participate in the study. Ultrasonography and serum oestradiol and progesterone measurements were performed during two assessment periods. The 75 microgram dose showed complete suppression of ovulation and a more acceptable bleeding pattern than the lower doses. The 75 microgram dose of desogestrel is the most promising dose for the development of a new progestogen-only oral contraceptive agent.

Alcohol use and reported physician visits in older adults

BACKGROUND

In general, older adults use a greater proportion of health care services than other age segments of the population. Alcohol abusers also use a greater proportion of health care services than alcohol nonabusers. Therefore we expected that among older adults, alcohol consumption would be positively related to health service use. In a sample of older adults, this study examined the relationship between alcohol consumption and an indicator of health service use--the self-reported number of physician visits.

METHODS

Data obtained on adult participants in the 1990 National Health Interview Survey, age 60 and older (n = 10,522), were examined. The number of physician visits was regressed on health status and alcohol consumption measures.

RESULTS

Counter to a priori expectations, alcohol consumption was negatively associated with physician visits. This finding was obtained after adjusting for respondent sex and health status measures.

CONCLUSIONS

Other research suggests that the rates of alcohol-related hospital admissions among older adults are on par with those of myocardial infarctions--an indication that harmful use of alcohol in older adults is going undetected. We found heavier alcohol consumption associated with fewer physician visits. This underscores the need for a better understanding of the role alcohol serves in the health perceptions of older adults. Broadening our knowledge in this area would be of benefit not only to the well-being of individuals also for health services policy considerations.

Ocular effects of exposure to triethylamine in the sand core cold box of a foundry

OBJECTIVES

To assess the acute and chronic ophthalmological effects of triethylamine exposure among foundry workers.

METHODS

Ocular effects on people currently, previously, and never exposed to triethylamine in a foundry cold box were studied at two points in time. The initial phase included an ocular examination with a slit lamp to assess corneal health, a visual acuity test, and a questionnaire to assess vision symptoms. The follow up included measurements of corneal thickness with an ultrasonic pachymeter and the vision symptoms questionnaire before and after the shift and at the beginning and end of the week. Personal air measurements for triethylamine were also obtained during the follow up.

RESULTS

The vision symptoms of blurriness, halos around lights, and blue hazy vision occurred more often in currently exposed workers than those previously or never exposed to triethylamine. Air concentrations of triethylamine ranged from < 0.33 mg/m3 to 20.3 mg/m3. Among currently exposed workers, symptoms were more common among those with exposure to > 10 mg/m3 of triethylamine (odds ratio (OR) = 3.0, 95% confidence interval (95% CI) 0.35-25.6). No differences in corneal thickness were found in currently or previously exposed workers and those never exposed. No increase in corneal thickness was found after v before the shift.

CONCLUSION

Despite low concentrations of triethylamine and no corneal oedema, workers exposed to triethylamine reported vision symptoms. Possible explanations for these symptoms without corneal oedema are that triethylamine affects ciliary muscle function or that the corneal oedema was transient and not present when corneal thickness measurements were taken. No chronic effects were found in previously exposed workers. Further research is needed to elucidate the mechanism for the reported vision symptoms, which occurred below the current United States eight hour time weighted standard of 100 mg/m3 and the American Conference of Governmental Industrial Hygienists (ACGIH) recommended value at the time of our study of 40 mg/m3. We recommend that air concentrations be maintained to meet the current recommended ACGIH threshold of 4.1 mg/m3.

Issues in the development of subject recruitment strategies and eligibility criteria in multisite trials of matching

Decision-making in selecting and recruiting subjects for treatment matching research is a complex process involving conceptual, methodological and practical considerations. In selecting clients, concerns arise about whether the criteria will produce a subject population that is (1) relevant to the dimensions associated with the treatment matching, (2) representative of persons typically seen in alcohol treatment settings and, for practical purposes, (3) able or willing to comply with the requirements of the study protocol. Also, in order to fulfill sampling requirements, it may be necessary to employ a variety of creative outreach methods. However, these recruitment mechanisms can pose additional logistical and methodological problems for the research. This article focuses on various issues arising in the selection and recruitment of subjects in matching research. Project MATCH serves to highlight issues related to client eligibility and recruitment and to discuss effective strategies for resolving these matters.

Influence of particle dose on the cytotoxicity of hamster and rat pulmonary alveolar macrophage in vitro

Silica and ferric oxide are common industrial exposures. Studies have indicated that all commonly occurring forms of crystalline silica can cause fibrotic lung disease. There is evidence to indicate that crystalline silica is carcinogenic in humans who have not developed silicosis, while amorphous silica is not carcinogenic in humans. An important biological response to particles deposited deep in the lung is their engulfment by pulmonary alveolar macrophages (AM). To assess the role of AM in silica-induced lung disease, particle size distribution and surface area of crystalline, gelled, precipitated, and fumed silica, ferric oxide, and aluminum oxide were characterized; the cytotoxicity of the particles to hamster and rat AM in vitro was measured at 0.0-0.5 mg/1 x 10(6) cells at 24 and 48 h using dye exclusion procedures. The count medium diameter for aluminum oxide, ferric oxide, and amorphous silica was equal to or less than 0.38 microns, while for crystalline silica the value was 0.83 microns. The surface areas for the amorphous silicas and the aluminum oxide ranged from 253 to 125 m2/g with gelled silica having the highest value; the values for crystalline silica and ferric oxide were 4.3 and 10.8 m2/g, respectively. Crystalline silica (1.6%) was detected in the fumed silica, while none was detected in precipitated or gelled silica. With gelled silica, based on the dose of the particle, the viability of the hamster AM decreased to 27% at 0.05 mg and to zero at 0.1 mg at 24 h. At doses of 0.05 and 0.1 mg of crystalline, precipitated, or fumed silica, the percent viability decreased significantly to 76-67% and 51-42%, respectively, and to zero at 0.5 mg. Macrophages viable at 24 h decreased further at 48 h compared with the control culture. The ferric oxide and the aluminum oxide showed minimal to no changes in viability. Similar results for the particles were obtained with rat AM. The results indicate that precipitated and fumed amorphous silica tested at equivalent doses are equally as toxic to AM lavaged from two species of rodents as crystalline silica; gelled silica is more toxic than crystalline. Ferric oxide and aluminum oxide are noncytotoxic in this system. The results of this study indicate that the dose as well as the surface area and surface characterization are important determinants in the cytotoxicity of hamster and rat AM to these particles.

Health status of pesticide applicators: postural stability assessments

Postural sway testing was performed on 37 pesticide-exposed workers and 35 nonexposed subjects. All subjects were asymptomatic. When ratios of sway measurements in different test conditions were investigated, total length of sway was significantly different between groups (P = .0001). Weight/height (P = .0006), exposure to pesticides (P = .0215), recent organophosphate exposure (P = .0391), and plasma cholinesterase level (P = .1537) were associated with increased body sway. The pattern of sway performance suggested a proprioceptive impairment, well compensated by visual cues, potentially attributable to pesticide exposure. This finding is of unclear clinical significance because results of neurologic examinations and nerve conduction studies that were reported separately did not show evidence of neuropathy. Postural sway testing is a simple, sensitive, noninvasive, and reproducible technique to evaluate subtle neurologic dysfunction. These findings are preliminary. Further studies are required to validate the findings and, if confirmed, to explore their functional or clinical significance.

Age group differences in response to treatment for problematic alcohol use

That structural characteristics act as markers of modified treatment outcome is a long standing idea in the alcohol treatment field. In order to test whether patient age is a factor to be considered in making treatment assignments, we examined data collected under a clinical trial. Two hundred and twenty-nine patients were randomly assigned to one of three treatment conditions: extended cognitive behavioral treatment (CB), relationship enhancement (RE), or relationship and vocational enhancement (VE). This paper reports on outcome (alcohol use) 3-6 months after treatment assignment. Our question was, would different age groups assigned to the treatment conditions exhibit different outcomes? There were no significant main effects by either treatment condition or age group. There was a significant treatment condition by age group interaction. With increasing age, the differences in treatment seemed to increase. For the younger aged group (18-29 years old) no statistically significant treatment differences were detected. Middle aged patients (30-49 years old) did best in the RE condition. Older aged patients (50 + years old) did best when assigned to the CB condition. These findings lead us to conclude that patient age is a variable which should be considered when testing patient-treatment matching hypotheses.

Is smoking associated with height and weight?

The reported relationship between height and smoking was tested using data from a representative sample of the U.S. population (N = 41,014). Both height and weight were associated with smoking. A further analysis for males and females separately showed that the initial results were a result of confounding of the variables with gender.

A randomised prospective study comparing the new vacuum extractor policy with forceps delivery

OBJECTIVE

To compare assisted vaginal delivery by forceps with delivery by vacuum extractor, where a new vacuum extractor policy was employed which dictated the cup to be used in specific situations.

DESIGN

Multicentre randomised controlled trial.

SETTING

Four district general hospitals in the West Midlands.

SUBJECTS

Six hundred-seven women requiring assisted vaginal delivery, of whom 296 were allocated to vacuum extractor delivery and 311 to forceps.

MAIN OUTCOME MEASURES

Delivery success rate, maternal perineal and vaginal injuries, maternal anaesthetic requirements, neonatal scalp and facial injuries.

RESULTS

Of the vacuum extractor group, 85% were delivered by the allocated instrument compared to 90% in the forceps group (odds ratio (OR) 0.64; 95% confidence intervals (CI) 0.4-1.04). However, more women in the vacuum extractor group were delivered vaginally (98%) than in the forceps group (96%). There were significantly fewer women with anal sphincter damage or upper vaginal extensions in the vacuum extractor group (11% vs 17%, OR 0.6; 95% CI, 0.38-0.97). There were significantly fewer women in the vacuum extractor group requiring epidural or spinal anaesthetics (25.4% vs 32.7%, OR 0.69; 95% CI 0.49-0.99) or general anaesthetics (1% vs 4%, OR 0.17; 95% CI 0.04-0.76). Although there were significantly more babies in the vacuum extractor group with cephalhaematomata (9% vs 3%, OR 3.3; 95% CI 1.4-7.4) there were fewer babies in the vacuum extractor group with other facial injuries. There were three babies in the forceps group with unexplained neonatal convulsions.

CONCLUSIONS

Assisted vaginal delivery using the new vacuum extractor policy is associated with significantly less maternal trauma than with forceps. Further studies are required to assess neonatal morbidity adequately.

Renal findings in 40 individuals with Williams syndrome

We tabulated the frequency of renal abnormalities in 40 Williams syndrome individuals presenting for medical and/or developmental assessment to a multi-disciplinary Williams syndrome program. The average age at time of assessment was 7 2/12 years. Seven individuals (7/40 = 18%) had abnormalities detected, including nephrocalcinosis = 2; marked asymmetry in kidney size = 2; small kidneys = 1; solitary kidney = 1; and pelvic kidney = 1. Renal function was also assessed. Two individuals had evidence of renal dysfunction, one secondary to nephrocalcinosis and the second due to hypercalcemia and interstitial nephritis of unclear pathogenesis. We examined the frequency of renal artery stenosis in 9 individuals who underwent abdominal angiography during cardiac catheterization. We found unilateral or bilateral mild renal artery narrowing in 4 individuals and normal renal arteries in the remaining 5. Persistent hypertension occurred in only 2 individuals and did not correlate with renal artery status. We conclude that intrinsic renal anomalies, as well as problems secondary to hypercalcemia, occur with sufficient frequency to warrant baseline renal screening in all individuals with Williams syndrome.

Physician use among patients receiving cancer chemotherapy

BACKGROUND

Little research has examined the volume and pattern of physician use or the scope of multiple physician use in patients with cancer.

METHODS

The authors studied a sample of 259 patients with advanced cancer who received outpatient chemotherapy at two hospital clinics and eight private oncology practices.

RESULTS

These patients reported regularly seeing an average of three different physicians an average of 15 times in 3 months. The number of physicians seen was strongly correlated with the number of reported visits (r = 0.65). Demographic and disease characteristics were associated only moderately with visit volume. Patients without a regular physician had a less concentrated pattern of visits to many doctors than did those with a regular doctor.

CONCLUSIONS

This pattern of physician use among active treatment patients has not been described before and has implications for continuity of care.