Biomedical subjects

R F Raubertas

Publications and source records attributed to R F Raubertas.

At least 37 records · Page 2Linked to original sources

PubMed1998

Autotransplantation for relapsed or refractory Hodgkin's disease: long-term follow-up and analysis of prognostic factors.

Seventy consecutive patients with refractory or relapsed Hodgkin's disease who received high-dose chemotherapy followed by autologous stem cell rescue were analyzed to identify clinically relevant predictors of long-term event-free survival. High-dose therapy consisted primarily of carmustine (BCNU), etoposide, cytarabine and cyclophosphamide (BEAC). The 5-year Kaplan-Meier event-free survival (EFS) for the entire cohort was 32% (95% confidence interval; 18-45%) with a median follow-up of 3.6 years (range 7 months-7.6 years). The most significant predictor of improved survival was the presence of minimal disease (defined as all areas < or =2 cm) at the time of transplant: the 5 years EFS was 46 vs 10% for patients with bulky disease (P = 0.0002). Other independent predictors identified by step-wise regression analysis included the presence of non-refractory disease and the administration of post-transplant involved-field radiotherapy (XRT). Treatment-related mortality occurred in 13 of 70 patients: nine patients (13%) died within the first 100 days, mainly from cardiopulmonary toxicity. However, only one of 24 patients (4%) transplanted during the last 4.5 years died from early treatment-related complications. While high-dose therapy followed by autotransplantation led to long-term EFS of 50% for patients with favorable prognostic factors, a substantial proportion of patients relapsed, indicating that new therapeutic strategies are needed.

Adult↗

PubMed1997

Health insurance for low-income working families. Effect on the provision of immunizations to preschool-age children.

BACKGROUND: The out-of-pocket cost for immunizations is a cause for referral to public health department clinics and is associated with delayed immunization. In 1991, New York State started Child Health Plus (CHPlus), an insurance program that covers ambulatory care and immunization services for children of families earning less than 222% of the poverty level. OBJECTIVE: To determine the effect of CHPlus on the provision of immunizations. DESIGN: A before-and-after design was used to compare the year immediately before enrollment in CHPlus with the first year after enrollment in CHPlus. A mixed-model analysis of variance was used to control for the effects of age. SETTING: All area primary care practices (n = 164) and public health department clinics (n = 6). SUBJECTS: Children (n = 1730) younger than 6 years who were enrolled in CHPlus. MAIN OUTCOME MEASURES: Number of immunization visits; types of providers (public health department clinics or primary care providers [pediatricians and family physicians]); and series-complete immunization coverage, including the diphtheria toxoid, tetanus toxoid, and pertussis vaccine, the oral poliovirus vaccine, and the measles, mumps, and rubella vaccine. RESULTS: The average age of the children was 37.7 months, 85% were white, 50% had been uninsured for immunizations before enrollment in CHPlus, and 16% previously received Medicaid. For infants, CHPlus decreased immunization visits to public health department clinics by 37% (from 0.14 to 0.09 visits per child, P = .009), increased immunization visits to primary care providers' offices by 15% (from 2.3 to 2.7 visits per child, P = .001), and increased immunization coverage by 7% (from 76% to 83%, P = .03). For children aged 1 to 5 years, CHPlus decreased visits to public health department clinics by 67% (from 0.06 to 0.02 visits per child, P < .001), increased visits to primary care providers' offices by 27% (from 0.46 to 0.59 visits per child, P < .001), and increased immunization coverage by 5% (from 83% to 88%, P < .001). The effects were greatest among previously uninsured children and among those with a gap in insurance coverage that was longer than 6 months. CONCLUSIONS: Insurance coverage for low-income working families resulted in a shift in the provision of immunizations from the health department to primary care providers and in increased immunization coverage.

Ambulatory Care↗

PubMed1997

Influence of maternal lead ingestion on caries in rat pups.

Lead is one of the most toxic and pervasive pollutants in society, and although there has been some lowering of blood lead levels in recent years, the levels continue to be of concern for African Americans, central city residents, residents in the Northeast region of the United States, persons with low income, and those with low educational attainment. Notably, these are the persons and the region where the highest prevalence of dental caries is observed. Information relating lead toxicity to oral health is sparse, but the preponderance of epidemiological data shows a relation between lead in the environment and the prevalence of dental caries. Using our well-defined rat caries model we found that pre- and perinatal exposure to lead results in an almost 40% increase in the prevalence of caries and a decrease in stimulated parotid function of nearly 30%. Levels of lead in milk from lead-treated dams were approximately 10 times as high as the corresponding blood lead levels, suggesting that lead is being concentrated by mammary glands. These findings may help in part to explain the comparatively high levels of dental caries observed in the inner cities of the United States where exposure to lead is common. Environmental sources of lead include drinking water, lead-based paint and, to a lesser extent, automobile and industrial emissions. In humans lead is accumulated and stored in bones (half-life of approximately 62 years), and even maternal exposure to lead decades before pregnancy can subsequently result in exposure of the developing fetus to elevated levels of lead. Moreover, lead concentration in maternal blood has been shown to increase during pregnancy and lactation because of mobilization of stored lead from bone, and typically, lead is found in milk at a higher concentration than the level found in maternal plasma at the same time point.

Animals↗

PubMed1997

Autotransplantation for relapsed or refractory non-Hodgkin's lymphoma (NHL): long-term follow-up and analysis of prognostic factors.

One hundred and thirty-six patients autografted for relapsed or refractory non-Hodgkin's lymphoma (NHL) were evaluated to assess long-term event-free survival and to identify important prognostic factors. High-dose therapy consisted primarily of carmustine (BCNU), etoposide, cytarabine, and cyclophosphamide (BEAC) followed by unpurged autologous stem cell rescue. The 5-year Kaplan-Meier event-free survival (EFS) for the entire cohort was 34% (95% confidence interval: 24-44%) with a median follow-up of approximately 3 years (range 0-7.5 years). For patients entering with minimal disease (defined as all areas < or = 2 cm), the 5-year EFS was 40 vs 26% for those entering with bulky disease (P = 0.0004). In the multivariate analysis, minimal disease on entry and administration of involved-field XRT post-transplant were significantly associated with improved EFS; the latter association was observed mainly in the cohort of patients with bulky disease. The overall 100-day treatment-related mortality rate was 4.4% (3% for the last 71 patients). New strategies are needed to reduce the high rate of relapse (50-60%) following auto-transplantation for relapsed or refractory NHL.

Adolescent↗

PubMed1996

An observer study for direct comparison of clinical efficacy of electronic to film portal images.

PURPOSE: To directly compare clinical efficacy of electronic to film portal images. METHODS AND MATERIALS: An observer study was designed to compare clinical efficacy of electronic to film portal images acquired using a liquid matrix ion-chamber electronic portal imaging device and a conventional metal screen/film system. Both images were acquired simultaneously for each treatment port and the electronic portal images were printed on gray-level thermal paper. Four radiation oncologists served as observers and evaluated a total of 44 sets of images for four different treatment sites: lung, pelvis, brain, and head/neck. Each set of images included a simulation image, a double-exposure portal film, and video paper prints of electronic portal images. Eight to nine anatomical landmarks were selected from each treatment site. Each observer was asked to rate each landmark in terms of its clinical visibility and to rate the ease of making the pertinent verification decision in the corresponding electronic and film portal images with the aid of the simulation image. RESULTS: Ratings for the visibility of landmarks and for the verification decision of treatment ports were similar for electronic and film images for most landmarks. However, vertebral bodies and several landmarks in the pelvis such as the acetabulum and public symphysis were more visible in the portal film images than in the electronic portal images. CONCLUSION: The visibility of landmarks in electronic portal images is comparable to that in film portal images. Verification of treatment ports based only on electronic portal images acquired using an electronic portal imaging device is generally achievable.

Observer Variation↗

PubMed1996

Detection and significance of myocardial ischemia in women versus men within six months of acute myocardial infarction or unstable angina. The Multicenter Myocardial Ischemia Research Group.

Ischemia detection after an acute coronary event predicts subsequent cardiac events. However, gender-related aspects in the prevalence and prognostic significance of ischemia detection after an acute coronary event have not been reported. Noninvasive tests, which included resting 12-lead electrocardiogram (ECG), 24-hour ambulatory ECG, exercise ECG, and thallium-201 stress scintigraphy were performed in 936 stable patients (224 women and 712 men) 1 to 6 months (average 2.7) after an acute coronary event (i.e., myocardial infarction or unstable angina). Primary end points during an average follow-up of 23 months included cardiac death, nonfatal myocardial infarction, and unstable angina, while restricted end points included the first 2. Ischemia detection was significantly less frequent among women than among men on 24-hour ambulatory ECG, exercise ECG, and thallium-201 stress scintigraphy. Primary end points occurred in 19.2% of women and in 19% of men, and restricted end points occurred in 5.8% of women versus 8%. of men (p = NS). Cox analyses revealed that gender and its interaction with each of the ischemia tests did not contribute to the prediction of the primary or restricted end points. We conclude that in stable patients 1 to 6 months after an acute coronary event, ischemia detection by noninvasive tests was significantly less prevalent in women than in men. However, subsequent cardiac event rates in women were similar to those observed in men, and there was no gender-ischemic detection interaction regarding subsequent events.

Angina, Unstable↗

PubMed1996

Effect of emergency department immunizations on immunization rates and subsequent primary care visits.

BACKGROUND: The Standards for Pediatric Immunization Practices recommend the routine use of emergency department (ED) encounters for screening the immunization status of children and, if indicated, immunizing them. OBJECTIVE: To test the hypothesis that ED immunizations will improve immunization rates without decreasing subsequent primary care visits. DESIGN: A randomized controlled trial of 2 interventions. Children (aged 6-36 months) (n = 1835) were enrolled in the study in the ED; informed consent was obtained from their parents. They were randomized into 1 of 3 groups: (1) the control group (n = 614), in which no intervention was undertaken; (2) the letter group (n = 610), in which a letter to the primary care physician was written indicating the child's estimated likelihood of being underimmunized; and (3) the ED vaccination group (n = 611), in which, based on a decision rule, those likely to be underimmunized were offered immunizations in the ED. After randomization, parents were interviewed in the ED using a decision rule to estimate the likelihood of the child being underimmunized. One year after enrollment in the study, the medical records of the children at their primary care sites were reviewed to determine the immunization status of the children and primary care use patterns. SETTING: An urban ED and 54 primary care sites in Monroe County, New York. RESULTS: The mean age of the participants was 17.9 months. Medical record review-verified underimmunization rates at the time of the ED visit were 33%, 31%, and 28% for the control, letter, and ED vaccination groups, respectively. The demographic characteristics and baseline immunization rates were not different among study groups. According to the decision rule, 248 children (41%) in the ED vaccination group were likely to be underimmunized. Parents of these 248 children were offered immunizations for their children; 117 (47%) accepted, and their children were immunized (with 230 separate immunizations). One month after the ED visits, the underimmunization rates of the study groups were 31%, 28% (P = .40 compared with the control group), and 23% (P = .002). One year later, these rates were 28%, 25% (P = .20), and 25% (P = .20). No clinically meaningful differences were present at either of these times. One year after the ED visit, no differences in the rates of primary care use were found among groups. CONCLUSIONS: This study provides evidence that the immunization of children in this ED was ineffective at raising their immunization rates; primary care attendance was also unaltered. Major obstacles were as follows: (1) an inability to ascertain accurately the immunization status in the ED and (2) a high rate of parental refusal to accept immunizations in the ED. The standards should be modified to de-emphasize the ED as a routine immunization site for children with access to primary care. Efforts and resources should be directed toward strengthening the primary care system and tracking immunization status.

Child, Preschool↗

PubMed1996

Comparison between Japan and North America in the post-hospital course after recovery from an acute coronary event.

We compared the post-hospital prognosis after an acute coronary event (acute myocardial infarction and unstable angina) in 106 patients in Japan vs. 789 patients in North America who were prospectively enrolled in the Multicenter Study of Myocardial Ischemia and were followed-up for an average of 26 months per patients. Risk factors more frequent in Japan were older age, males and smoking at enrollment, but the rest of many risk factors were similar. After adjusting for differences in clinical and medication variables, Cox analyses indicated patients in North America had a significantly greater risk of experiencing a primary end-point (cardiac death, non-fatal myocardial infarction or unstable angina) than patients in Japan (hazard ratio [North America:Japan] = 3.1, P = 0.003). There was a non-significant trend in the restricted end-points (cardiac death or non-fatal myocardial infarction) with North America having more frequent events than Japan (hazard ratio = 2.2, P = 0.12). The long-term outcome after recovery from an acute coronary event is more favorable in Japan than in North America, mostly due to a reduction in subsequent hospitalization for unstable angina. The reason for these findings cannot be explained by differences in the measured risk factors or medications.

Adult↗

PubMed1996

Response of Photofrin-sensitised mesothelioma xenografts to photodynamic therapy with 514 nm light.

We have studied the response of human mesothelioma xenografts in nude mice to Photofrin-sensitised photodynamic therapy with 514 nm light. Delays in tumour regrowth following four different 514 nm irradiation regimens were compared with results obtained with the more commonly used 630 nm light. One of these 514 nm regimens, which consisted of 1 h of irradiation at an incident fluence rate of 20 mW cm-2 and a second hour at a fluence rate of 28 mW cm-2, produced tumour volume doubling times that were statistically indistinguishable from results that were observed when tumours were irradiated for 2 h with 630 nm light at an incident fluence rate of 50 mW cm-2. The three other 514 nm light protocols tested were found to be less effective than the 630 nm regimen. The 514 nm treatment protocols were devised on the basis of attempts to equate the photodynamic dose and the dose rate at these two wavelengths, with photodynamic dose defined as the number of photons absorbed by the sensitiser. Photosensitiser extinction coefficients, photon energies and tissue optical properties were considered in these attempts. Our results indicate that, under certain conditions, photodynamic therapy performed with 514 nm light can provide tumour control that is similar to that achieved with 630 nm, with potential for diminished normal tissue damage.

Animals↗

PubMed1996

Effect of sucralose--alone or bulked with maltodextrin and/or dextrose--on plaque pH in humans.

Sucralose is a safe, intensely sweet, noncaloric sucrose derivative that has been shown to be noncariogenic. The purpose of the present study was to compare the effects on plaque pH in vivo of sucralose in iced tea (alone or bulked with maltodextrin or with maltodextrin/dextrose) with sucrose in iced tea. Fourteen subjects, with DMFT > 7 and an acidogenic plaque, participated in the study. Plaque pH response to one of five solutions: unsweetened tea, tea with sucralose (final concentration 0.007% by weight), tea with sucralose/maltodextrin (final concentrations 0.007% and 0.59% by weight, respectively), tea with sucralose/maltodextrin/dextrose (final concentrations 0.007, 0.018 and 0.57% by weight, respectively) and tea with sucrose (final concentration 4.7% by weight); was assessed in five experimental sessions. All solutions, except the unsweetened tea, had a sweetness equivalent to 2 teaspoons of sucrose in 6 OZ of beverage. Using a touch electrode, plaque pH was measured at baseline and at specific time intervals up to 60 min after rinsing with the test solution for 1 min. Comparisons between groups were done for minimum pH, delta pH, and area under the pH curve (AUC), by using the nonparametric Friedman's test and the Wilcoxon signed rank test. Rinsing with tea and sucrose resulted in significantly lower minimum pH, higher delta pH and larger AUC than rinsing with the solutions containing sucralose. It can be concluded that sucralose alone or in combination with maltodextrin or with maltodextrin/dextrose is significantly less acidogenic than sucrose when used as a sweetener in iced tea.

Adult↗

PubMed1995

Adjuvant chemotherapy does not affect employment in patients with early-stage breast cancer.

OBJECTIVE: To assess the impact of adjuvant chemotherapy for the management of breast cancer on subsequent patient employment. DESIGN: Retrospective cohort study. SETTING: University-affiliated community hospital cancer center. PATIENTS: Patients who were 18 to 65 years old and were diagnosed as having breast cancer stages 0, I, II, and IIIa between January 1986 and January 1991 were contacted and asked whether they had been employed at the time of the diagnosis. The 145 patients who had breast cancer and who had been working at the time of diagnosis completed a questionnaire, which included questions regarding demographic characteristics, employment history, and the reasons for any period of unemployment. The 76 patients who had received adjuvant chemotherapy were compared with the 69 who had not. MEASUREMENTS AND RESULTS: The main endpoint was return to work by one, three, six, and 12 months after surgery. Of the 76 patients who had received chemotherapy, 70 (92%) had resumed work by 12 months after treatment began. Of the 69 who had not been treated with chemotherapy, 65 (94%) had resumed work in 12 months. The proportions of patients who had returned to work by one, three, and six months were similar in the two groups. Regression analyses demonstrated no significant confounding or interaction of adjuvant treatment with age, menopausal status, marital status, years of education, or type of job in regard to return to work. CONCLUSIONS: Adjuvant chemotherapy does not delay or prevent return to work in women treated for early-stage breast cancer.

Adult↗

PubMed1995

Association of free arginine and lysine concentrations in human parotid saliva with caries experience.

We determined the free-amino acid content of stimulated parotid (ductal) saliva from two groups of adult subjects whose caries experiences were markedly different. The levels of free arginine and free lysine in the parotid saliva of caries-free adults were significantly higher than those found in the parotid saliva of individuals with a history of dental decay. There was no correlation, however, between the levels of these amino acids and the DMFS score within the caries-susceptible groups. Microbial catabolism of dibasic amino acids contributes to the neutralization of plaque acids and may partially account for the higher resting plaque pH observed in caries-free subjects. Alternatively, the elevations observed in free levels of arginine and lysine may reflect a systemic alteration in amino acid metabolism which is common to the caries-free group of subjects.

Adolescent↗

PubMed1995

When does palliative care begin? A needs assessment of cancer patients with recurrent disease.

This cross-sectional study compared the prevalence and intensity of needs expressed by cancer patients at the time of first recurrence (n = 75) with those of patients at the time of disease progression (n = 75). On a 72-item Likert-type scale participants rated from "none" to "very much" the severity of physical symptoms; emotional, psychological, and social problems; and difficulties with activities of daily living. The progressive disease group reported more problems than the first recurrence group in 11 of 24 (47%, p < 0.05) symptom-related questions. The progressive disease group also expressed greater needs in 19% of the function-related questions. There were no differences in reported psychological problems, responses to recurrence, or greatest concern between the two groups. These results support the need for palliative care throughout the entire course of illness.

Adult↗

PubMed1995

Quantification of micro-regional heterogeneities in tumor oxygenation using intravascular HbO2 saturations.

Despite promising reports as to the relationship between tumor radiosensitivity and overall tumor oxygenation, little additional information has been forthcoming regarding the importance of localized variations in tumor oxygen distribution. The objectives of the current study were (1) to devise a strategy for sampling tumor HbO2 saturation distributions and (2) to compare intratumor heterogeneities in HbO2 profiles with intertumor variability to determine whether representative tumor oxygen profiles can be obtained from a limited tumor sample. Using murine KHT fibrosarcomas, maps of tumor intravascular HbO2 saturations were obtained using cryospectrophotometric techniques and without the use of anesthetics. Micro-regions composed primarily of either high or low HbO2 vessels were observed in both peripheral and interior regions of the KHT tumors, although HbO2 levels were higher, on average, toward the periphery. To quantify intra- and intertumor heterogeneities in oxygen delivery, alternative HbO2 sampling protocols were evaluated in comparison to all-inclusive HbO2 maps for each tumor cross section. Since intratumor variations in HbO2 distributions were of the same order of magnitude as intertumor variations for tumors of a single tumor line, it is clear that tumor micro-regional physiology cannot be characterized adequately by a single regional sample.

Animals↗

PubMed1994

Immunization practices of primary care practitioners and their relation to immunization levels.

OBJECTIVES: To assess variations in immunization practices and attitudes among primary care providers and to relate these characteristics to the immunization levels of their patients. SETTING: Monroe County, New York. DESIGN: Survey of pediatricians (n = 96) and family practitioners (n = 44) to assess immunization practices and attitudes and medical chart reviews for 1884 patients of 32 physicians who practice in the city of Rochester to measure immunization levels. ANALYSIS: Tabular analyses for survey responses (chi 2 test and Fisher's Exact Test); logistic regression to assess the relation between provider responses and measured immunization levels. RESULTS: Responses by pediatricians and family practitioners were similar. Most providers did not routinely immunize during acute-illness visits but did immunize during follow-up or chronic-illness visits. Few used tracking systems to identify underimmunized children. Most practitioners immunized children who had colds but withheld immunizations from children who had fevers or otitis media. Most providers agreed with expanding immunization programs to include sick visits, health department clinic visits, and community site visits, but most thought that they should not be provided at emergency department visits, except for very-high-risk children. Immunization levels at 10 months of age were positively correlated with private practice setting (P = .001) but negatively correlated with immunizing at acute- (P < .01) or chronic-illness (P < .05) visits, Medicaid coverage (P < .05), and high rates of appointments that were not kept (P < .001). CONCLUSIONS: Primary care providers' immunization practices and attitudes vary and do not always follow established guidelines for immunization delivery. Many providers of high-risk children are already attempting to improve immunization delivery by using patient reminders and by immunizing children at acute- or chronic-illness visits. Improving provider immunization practices to deliver childhood immunizations more effectively must be part of our efforts to resolve this nation's childhood immunization problem.

Adolescent↗

PubMed1994

Effects of photodynamic therapy on xenografts of human mesothelioma and rat mammary carcinoma in nude mice.

We have examined the effectiveness of photodynamic therapy against R3230AC rat mammary adenocarcinoma and human mesothelioma as xenografts in the same host. The results demonstrate that the xenografted human tumour is significantly more responsive to photodynamic treatment than the rodent mammary tumour. Studies also showed that the mesothelioma xenograft was fluence rate- and fluence-dependent while the rat tumour exposed to the same conditions demonstrated neither of these dependencies. This disparity in response was not attributable to a difference in either whole-tumour uptake or subcellular distribution of the porphyrin photosensitiser. Analysis of the effects of visible irradiation on cytochrome c oxidase activity, measured in mitochondria prepared from tumours borne on hosts injected with photosensitiser, demonstrated that photoradiation-induced enzyme inhibition was significantly greater in mesothelioma than in R3230AC mammary tumour preparations. However, in parallel studies conducted in vitro, when photosensitiser and light were delivered to previously unperturbed mitochondria, rates of enzyme inhibition were not significantly different. Both tumours were established in long-term cell culture. While the uptake of porphyrin photosensitiser was equivalent in both cell lines, the R3230AC cells displayed a significantly greater photosensitivity than the mesothelioma cells. The data presented here demonstrate that the mechanisms that govern response to photodynamic therapy are complex, but in the case of these two xenografted tumours host response to therapy is not likely to play a significant role.

Adenocarcinoma↗

PubMed1994

Risk of subsequent cardiac events in stable convalescing patients after first non-Q-wave and Q-wave myocardial infarction: the limited role of non-invasive testing. The Multicenter Myocardial Ischemia Research Group.

BACKGROUND: Patients recovering from myocardial infarction are frequently evaluated by non-invasive tests for evidence of myocardial ischemia before returning to work or full activity. The purpose of this study was to evaluate the prognostic significance of clinical and non-invasive ischemic test variables assessed in 549 stable, convalescing patients (median 2 months) after their first Q-wave (n = 363) and non-Q-wave (n = 186) myocardial infarction. METHODS: The ischemic tests performed were resting ECG, exercise ECG, ambulatory ECG, and stress thallium scintigraphy. RESULTS: Cardiac events (unstable angina requiring hospitalization, non-fatal reinfarction, or death from cardiac causes) were observed during a mean 23-month follow-up in 57 patients (15.7%) with Q-wave and in 31 of patients (16.7%) with non-Q-wave infarction. In a step-wise Cox regression model, the only significant independent predictors of subsequent cardiac events (P < 0.001) were post-infarction angina and insulin-dependent diabetes mellitus. The type of infarction did not make a significant contribution to the risk of cardiac events (P = 0.29). However, an interaction between infarct type and post-infarction angina was of borderline significance (P = 0.065), with angina associated with more cardiac events in patients with non-Q-wave than in those with Q-wave infarction. None of the ischemic tests contributed significantly to the Cox model in predicting cardiac events in either infarct type. CONCLUSION: Stable convalescing patients who have recovered from first Q-wave and non-Q-wave myocardial infarction have similar long-term prognoses. The occurrence of post-infarction angina is associated with increased risk of cardiac events in patients with both infarct types, with more marked effect in non-Q-wave than Q-wave infarctions. Ischemia detected by non-invasive tests performed in the convalescing phase after myocardial infarction was not prognostically useful in either infarct type.

Convalescence↗

PubMed1994

Risk of subsequent cardiac events in stable convalescing patients after first non-Q-wave and Q-wave myocardial infarction: the limited role of non-invasive testing.

Angina Pectoris↗