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Biomedical subjects

R F Raubertas

Publications and source records attributed to R F Raubertas.

At least 55 records · Page 3Linked to original sources
PubMed1993

Hypothalamic-pituitary dysfunction after radiation for brain tumors.

BACKGROUND: Patients with brain tumors who are treated with radiation frequently have growth hormone deficiency, but other neuroendocrine abnormalities are presumed to be uncommon. METHODS: We studied endocrine function in 32 patients (age, 6 to 65 years) 2 to 13 years after they had received cranial radiotherapy for brain tumors. The doses of radiation to the hypothalamic-pituitary region ranged from 3960 to 7020 rad (39.6 to 70.2 Gy). Nine patients also received 1800 to 3960 rad (18.0 to 39.6 Gy) to the craniospinal axis. Serum concentrations of thyroid, gonadal, and pituitary hormones were measured at base line and after stimulation. RESULTS: Nine patients (28 percent) had symptoms of thyroid deficiency, and 20 patients (62 percent) had low serum total or free thyroxine or total triiodothyronine concentrations. Of the 23 patients treated only with cranial radiation, 15 (65 percent) had hypothalamic or pituitary hypothyroidism. Of the nine patients who also received spinal (and thus direct thyroid) radiation, three (33 percent) had evidence of primary thyroid injury. Seven of the 10 postpubertal, premenopausal women (70 percent) had oligomenorrhea, and 5 (50 percent) had low serum estradiol concentrations. Three of the 10 men (30 percent) had low serum testosterone concentrations. Overall, 14 of the 23 postpubertal patients (61 percent) had evidence of hypogonadism. Mild hyperprolactinemia was present in 50 percent of the patients. Responses to stimulation with corticotropin-releasing hormone and corticotropin were normal in all patients except one, who had panhypothalamic dysfunction. However, serum 11-deoxycortisol responses to the administration of metyrapone were low in 11 of the 31 patients (35 percent) tested. Three of the 32 patients, (9 percent) had no endocrine abnormalities, 9 (28 percent) had an abnormal result on tests of thyroid, gonadal, prolactin, or adrenal function, 8 (25 percent) had abnormalities in two axes, 8 (25 percent) in three axes, and 4 (12 percent) in all four axes. CONCLUSIONS: Cranial radiotherapy in children and adults with brain tumors frequently causes abnormal hypothalamic-pituitary function. The most frequent changes are hypothyroidism and gonadal dysfunction, although subtle abnormalities in adrenal function may also be present.

Adolescent↗
PubMed1993

Observer variation in interpretation of magnetic resonance images of the temporomandibular joint.

The purpose of this study was to measure interobserver and intraobserver variation in reporting magnetic resonance images of the temporomandibular joint. This study was based on magnetic resonance images of 149 joints. The images were interpreted independently by two of us on two occasions, 2 to 4 weeks apart. We were trained together before starting the study. The magnetic resonance images were interpreted for the position and configuration of the disk and osseous changes. The intraobserver agreement for reporting the position of the disk was 95%, configuration of the disk was 90%, and osseous changes was 97% (average of both observers). The agreement between the two observers was 90% on the position of the disk, 89% on the configuration of the disk, and 94% on reporting osseous changes (average of both readings). The results suggest that interobserver and intraobserver variation in reporting magnetic resonance images of the temporomandibular joint can be kept at a low level with high quality images, suitable training of the observers, and well-defined criteria for interpretation. The low observer variation together with the high diagnostic accuracy reported in other studies suggests that magnetic resonance imaging of the temporomandibular joint is a reliable and valid imaging technique for assessment of this joint.

Adolescent↗
PubMed1993

The short-form McGill Pain Questionnaire in chronic cancer pain.

A short form of the McGill Pain Questionnaire (SF-MPQ) was previously developed. It was found to correlate highly with and demonstrate differences due to treatment in a manner similar to the long form of the McGill Pain Questionnaire (LF-MPQ). The LF-MPQ was previously found to be a valid measurement of pain in the cancer population. The present study demonstrated that the sensory, affective, and total scores of the SF-MPQ correlated highly with the LF-MPQ on three administrations, each 3-4 wk apart in 24 patients with chronic pain due to cancer. Both the long and short total scores correlated highly with the visual analogue scale (VAS) and present pain intensity (PPI) scale. The SF-MPQ demonstrated changes over time in a manner similar to the LF-MPQ in this patient group. These observations support the value of the SF-MPQ as a tool for studying interventions in patients with chronic pain due to cancer.

Adult↗
PubMed1993

Decision rules for predicting vaccination status of preschool-age emergency department patients.

We produced and tested rules to predict undervaccination among preschool-age emergency department (ED) patients. Data were gathered on demographics, vaccination status, health status, and health care utilization from parents, ED physicians, and ED charts at an urban teaching hospital in Rochester, N.Y. Primary care charts were reviewed to verify vaccination status. Using recursive partitioning, we developed decision rules to predict undervaccination. Decision rules were developed on a sample of 602 ED patients 4 to 48 months of age and then prospectively tested on 1832 ED patients aged 6 to 36 months. Factors associated with undervaccination for any vaccine included parental report of vaccination delay (odds ratio = 8.1; p < 0.001), inability to report the receipt of the appropriate number of vaccines (odds ratio = 4.5; p < 0.001), lack of health insurance (odds ratio = 3.6, p < 0.001), elapsed time since the last visit to primary care provider (p < 0.001), household size (p < 0.001), and maternal age (p < 0.01). Eight decision rules were produced that varied in their number of questions (one to six), sensitivity (0.27 to 0.87), and specificity (0.54 to 0.98). No single rule was both highly sensitive and highly specific. The rules' sensitivities and specificities were similar for the validation sample of 1832 patients. Thus a decision rule could not be produced that was both sensitive and specific. Identification of undervaccinated children by means of information available at an ED visit is inherently difficult. Interventions in the ED may be inefficient unless better methods of assessing vaccination status can be developed.

Child↗
PubMed1993

Missed opportunities for childhood vaccinations in office practices and the effect on vaccination status.

To determine the rate of childhood under-vaccination, rate and types of missed opportunities (MOs) for vaccinations, and the contribution of MOs to the undervaccination of preschool-age children, the authors conducted a retrospective medical chart review in seven primary care settings in the Rochester, NY, area: a hospital clinic, a neighborhood health center, a group-model health maintenance organization, an urban group practice, a suburban group practice, a rural health center, and a rural private practice. The random sample included 1124 children having birth dates between March 15, 1988, and September 15, 1989. The main outcome measures were cumulative undervaccination rate, defined as the proportion of patients from each practice who were ever > 60 days past-due for a vaccination by 12, 18, or 24 months of age; undervaccination time, defined as the median number of months during which children were undervaccinated; number of MOs; visit types and conditions associated with the MOs; and the duration of undervaccination time attributable to MOs. The cumulative undervaccination rate by 12 months was at least 20% in each practice except for the suburban practice, where it was 4%. The frequency of MOs varied from a high of 1.8 MO per patient per year at the rural private practice to a low of 0.3 MO per patient per year at the suburban practice. More than one quarter of MOs occurred during either health supervision or follow-up visits in all practices. In 28% of visits during which an MO occurred, patients had no fever or acute illness.(ABSTRACT TRUNCATED AT 250 WORDS)

Child Health Services↗
PubMed1993

Is an emergency department visit a marker for undervaccination and missed vaccination opportunities among children who have access to primary care?

The purpose of this study was to determine: (1) whether preschool-age patients who utilize the emergency department (ED) are undervaccinated compared with patients having the same primary care provider and (2) whether reducing missed vaccination opportunities in the primary care office can potentially reduce the differences in undervaccination between the groups. This retrospective cohort study involved two groups: 583 ED patients, aged 4 to 48 months, who had primary care providers; and 583 control subjects randomly selected from primary care sites and matched according to date of birth and primary care site. The major outcome variable was the point prevalence of undervaccination, defined as more than 60 days past due for a vaccine at the time of the ED visit, and for control subjects, at the time of their matched patient's ED visit. Demographic variables, vaccination history, presence of chronic illness, and office utilization history were abstracted from office charts. The mean age of all patients was 20.0 months. Emergency department patients were more likely to be boys (61% vs 50%) and had more chronic illness, but did not differ racially from those in the control group. Primary care sites included a hospital-based clinic (n = 137), neighborhood health centers (n = 172), and private practices (n = 274). The undervaccination rates by primary provider type were for (1) hospital clinic ED patients 21.1%, control subjects 19.7%; (2) neighborhood health center ED patients 29.1%, control subjects 22.7%; and (3) private practice ED patients 26.6%, control subjects 14.9%. Overall, the odds ratio of ED patients' being undervaccinated compared with control subjects was 1.8 (95% confidence interval 1.3 to 2.5).(ABSTRACT TRUNCATED AT 250 WORDS)

Child, Preschool↗
PubMed1992

Studies of fluoride retention by oral soft tissues after the application of home-use topical fluorides.

Previous studies have focused on enamel and plaque as the primary sites of fluoride (F) retention in the mouth. The present study was undertaken to evaluate the role of oral soft tissue as a site of F retention by comparing an edentulous subject panel (n = 9) with a fully dentate panel (n = 10). Unstimulated whole saliva samples were collected by having subjects pool saliva for two min. Samples were collected over a 24-hour period after application of a placebo dentifrice (PD; 0.4 ppm F), fluoride dentifrice (FD; 1100 ppm F), fluoride rinse (FR; 226 ppm F), or fluoride gel (FG; 5000 ppm F) delivered in custom trays. There was no statistically significant difference in salivary flow rate between the two panels for any of the treatments. The edentulous panel had higher salivary F levels than the dentate panel, which reached statistical significance (p less than 0.05) for the FD and FG treatments. In a separate study involving the same treatments, F levels at specific soft-tissue sites were measured over a one-hour period by use of absorbent discs placed in different soft-tissue areas of the mouth. The tongue and lower posterior vestibule retained the highest F levels, followed by the upper posterior buccal vestibule and upper anterior labial vestibule, with the lowest F levels retained in the lower anterior vestibule and the floor of the mouth. There was a strong-to-moderate correlation between whole saliva F concentration and F levels at specific soft-tissue sites. This study establishes the importance of oral soft tissue as the major site of F retention in the mouth.

Analysis of Variance↗
PubMed1992

Fluoride concentrations in plaque, whole saliva, and ductal saliva after application of home-use topical fluorides [published eerratum appears in J Dent Res 1993 Jan;72(1):87].

It is now well-accepted that the primary anti-caries activity of fluoride (F) is via topical action. The retention of F in the mouth after topical fluoride treatment is considered to be an important factor in the clinical efficacy of F. The purpose of this study was to evaluate F levels in ductal saliva, whole saliva, and pooled plaque after treatment with topical F agents intended for home use. Ten consenting adults, mean (SD) age 31.0 (8.2) years, participated in all aspects of the study. Two days before each test, subjects received a professional tooth cleaning and subsequently abstained from all oral hygiene procedures to permit plaque to accumulate, and from the use of F-containing dental products. Treatments consisted of a placebo dentifrice (PD), fluoride dentifrice (FD; 0.24% NaF), fluoride rinse (FR; 0.05% NaF), and fluoride gel (FG; 1.1% NaF). Unstimulated whole saliva and pooled plaque were sampled at multiple points over a 24-hour period. In a separate experimental series, stimulated parotid saliva was sampled over a two-hour period after treatment. Fluoride levels generally followed the same pattern in whole saliva and pooled plaque samples, with FG > FR > FD > PD. Night-time F application resulted in prolonged F retention in whole saliva but not in plaque. Fluoride levels in parotid saliva were only slightly higher after F treatment and returned to baseline levels within two h. The results of this study indicate that the method of F delivery, the F concentration of the agent, and the time of application (daytime vs. night-time) are important factors influencing F levels in the mouth.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Treatment patterns in low-grade non-Hodgkin's lymphomas: a single institution study.

Ninety-two cases of low-grade non-Hodgkin's lymphoma were examined retrospectively to assess to what extent treatment deferral is practiced at a single university hospital with a local referral base. Clinical characteristics of this patient group were also analyzed; 70% of these cases were of nodular lymphocytic, poorly differentiated (NLPD) histology, and 74% were stage III or IV. Twenty-two cases were not treated initially. Nine eventually required treatment at a median of 16 months. Survival did not differ based on whether treatment was initially deferred. Nodal progression was the most common reason for beginning treatment after initial deferral, and most cases of advanced stage disease required treatment because of nodal involvement or B-type symptoms at diagnosis. Presence of intra-abdominal adenopathy often prompted initial treatment even in asymptomatic cases. In this series, as compared to previously reported series of treatment-deferred cases, more patients were judged to require treatment at disease outset, and the median time to treatment in those in whom treatment was initially deferred but then instituted was shorter. Despite this, for the entire population, 69% of total follow-up time was spent off therapy.

Actuarial Analysis↗
PubMed1991

Time-dependent effects of anesthetic agents on 31P NMR high-energy phosphates in KHT and RIF-1 fibrosarcomas.

Previous studies have reported significant radiobiological and hemodynamic effects associated with sodium pentobarbital (PB) anesthetization. The present work contrasts the effects of PB with azaperone-ketamine (AZ) in RIF-1 and KHT tumors while animal body core temperature is maintained at 37 degrees C. The primary aims were to evaluate both agents in terms of: (i) duration of anesthetic; (ii) effect on absolute levels of 31P NMR phosphocreatine (PCr) + beta-nucleoside triphosphate (beta-NTP)/inorganic phosphate (Pi) ratios; and (iii) effect on temporal variability of PCr + beta-NTP/Pi ratios. In terms of overall duration, AZ was the clear preference. Although the maintenance of 37 degrees C core temperature significantly reduced overall durations for both anesthetics, AZ animals invariably remained immobile for a minimum of 80 min. For PB, durations were highly unpredictable. With AZ, mean PCr + beta-NTP/Pi ratios were constant over the entire 80 min period for both lines. With PB, PCr + beta-NTP/Pi ratios were lower in relation to AZ for KHT at select timepoints, but highly variable among RIF-1 tumours. Since ratios under PB varied substantially with time for RIF-1 lines, measurements taken with PB are clearly not representative of the control state. Furthermore, in light of the consistent and reproducible results obtained with AZ, this anesthetic is considered a marked improvement over PB for animal studies of this nature.

Anesthetics↗
PubMed1991

Relevance of common tests of cerebrospinal fluid in screening for bacterial meningitis.

This study tests the hypothesis that if cerebrospinal fluid (CSF) has a nucleated blood cell count (NucBC) of less than 6/mm3, CSF tests other than bacterial culture need not be performed to exclude the diagnosis of bacterial meningitis in patients not receiving antimicrobial agents. The results of tests performed on the first specimen of CSF obtained for a given hospital visit from children younger than 3 years of age, exclusive of newborn infants admitted to the hospital on their date of birth, were analyzed. Of 3356 CSF specimens evaluated, 122 were from patients with bacterial meningitis; 460 specimens were analyzed separately because the erythrocyte count was greater than 1000/mm3. A negative CSF screening test result was defined as a CSF NucBC less than 6/mm3. In facilitating the diagnosis of bacterial meningitis, this screening test had a sensitivity of 98.4%, a specificity of 75.2%, and a negative predictive value of 99.9%. The other CSF tests varied widely in screening effectiveness: a Gram-stained smear had a sensitivity of 53% and a specificity of 97%. Receiver operating characteristic curve analysis was used to assess the screening relevance of CSF tests. The CSF NucBC and CSF segmented NucBC performed indistinguishably and superiorly compared with the CSF protein or glucose concentration and the ratio of CSF glucose to serum glucose concentration. Logistic regression analysis showed that the NucBC alone is superior to any combination of the other CSF tests. In a prospective study of 215 children younger than 3 years of age undergoing a lumbar puncture in our emergency department, 85% had empiric criteria identifying them as appropriate for an abbreviated CSF evaluation. The CSF NucBC was less than 6/mm3 in 70% of the 181 patients who would have been eligible for an abbreviated CSF evaluation. These data suggest that a strategy for the sequential testing of CSF could be adopted that would exclude unnecessary determinations and thereby save time, effort, and health care dollars.

Blood Glucose↗
PubMed1991

Endometrial carcinoma: the relevance of cervical cytology.

In patients with endometrial carcinoma, preoperative identification of poor prognostic factors is helpful in planning therapy. Extended surgical staging, including pelvic and periaortic node dissection, is indicated in patients with deep myometrial invasion or high-grade tumor, or when other risk factors for extrauterine spread are present. In this study, cervical cytology was reviewed in 86 patients with endometrial carcinoma, all of whom underwent surgical staging, to correlate the cytologic results with surgical and pathologic findings. Cervical cytology was normal in 20 patients (23%), whereas suspicious or malignant endometrial cells were present in 23 and 43 cases (27 and 50%), respectively. Suspicious or malignant cervical cytology was associated with deeper myometrial invasion (P = .011), higher postoperative tumor grade (P = .006), positive peritoneal washings (P = .012), and more advanced stage by International Federation of Gynecology and Obstetrics criteria (P = .024). When compared with patients with normal cervical cytology, those who had malignant endometrial cells had over twice the risk of deep myometrial invasion (67 versus 30%), twice the risk of grade 2 or 3 tumor (60 versus 30%), and three times the risk of positive peritoneal washings (33 versus 10%). Seventy-four percent of patients with malignant cervical cytology were stage IC or more. In contrast, 70% of patients with normal cervical cytology were stage IA or IB. Patients with endometrial carcinoma who have malignant endometrial cells detected by cervical cytology are at increased risk of having a deeply invasive, high-grade, advanced-stage tumor, and therefore are more likely to require extended surgical staging.

Adult↗
PubMed1990

Effects of various photoradiation regimens on the antitumor efficacy of photodynamic therapy for R3230AC mammary carcinomas.

Clinical photodynamic therapy consists of the systemic administration of a derivative of hematoporphyrin (Photofrin II) followed by exposure of malignant lesions to continuous visible laser irradiation. We investigated the effects of various modifications of laser light delivery on the efficacy of photodynamic therapy in controlling R3230AC mammary tumor growth. We observed a significant delay in growth (from initial to 2 times initial volume) of tumors exposed to periodic irradiation (100 mW/cm2/0.25 h, 1-h dark interval, 100 mW/cm2/0.25 h; total fluence, 180 J/cm2), compared to untreated controls or to tumors receiving continuous irradiation at the same total fluence. Other periodic light treatment regimens, consisting of 3-, 6-, or 24-hr dark intervals, delayed tumor growth but not significantly more than continuous irradiation at the same fluence. A biochemical basis was sought by comparing continuous versus periodic irradiation for effects on mitochondrial or cytosolic enzymes in vivo. Although both cytochrome c oxidase and pyruvate kinase activities were reduced dramatically during the first 24 h by continuous or periodic irradiation schemes, recovery of enzyme activity to initial levels took longer after the periodic irradiation protocol (168 h), compared to the continuous irradiation regimen (72 h). We observed a significantly greater delay in the growth of tumors exposed to 50 mW/cm2/2 h continuously, compared to controls or to tumors exposed to the same total fluence but with light delivered at 100 or 200 mW/cm2. The data presented here indicate that the efficacy of photodynamic therapy could be significantly increased by modifications in the delivery of photoradiation.

Animals↗
PubMed1990

Pregnancy rates after double versus single insemination with frozen donor semen.

Ninety-nine females (mean age 34 years +/- 1) were seen for therapeutic donor insemination using frozen semen. All patients used over-the-counter urinary ovulation predictor kits, with the insemination scheduled either the day after the positive test (group I; n = 46) or consecutively the day of and the day after the positive test (group II; n = 53). Group I patients underwent a total of 113 cycles of insemination (mean 2.5 cycles/patient). Seven pregnancies were achieved in group I for an overall success of 15.2% and a monthly fecundability of 0.06. Group II patients underwent a total of 100 cycles of therapeutic donor insemination (mean of 1.9 cycles/patient). Twenty-one pregnancies were achieved in this group for an overall success rate of 39.6% and fecundability of 0.21. The estimated cumulative probability of conception (F) for 6 months was 0.32 in group I and 0.78 in group II. These data indicate that the F after therapeutic donor insemination with frozen semen is greater if two consecutive inseminations are performed at midcycle.

Cryopreservation↗
PubMed1989

An analysis of disease surveillance data that uses the geographic locations of the reporting units.

The primary purpose of a disease surveillance system is to provide data for the detection of changes in the incidence of the disease. Methods for the analysis of data from surveillance systems are reviewed. A new procedure is proposed for use when the system includes geographically dispersed reporting units, such as hospitals or administrative regions. The method is based on the cusum statistic, and combines information from different units according to their geographic relationships.

Data Interpretation, Statistical↗
PubMed1989

The question of clustering of Creutzfeldt-Jakob disease.

Clustering of Creutzfeldt-Jakob disease has been reported in several countries. The authors review these reports, and they describe their statistical analysis of clustering among 329 cases that died in France during 1968-1982. Paris was found to have a much higher case rate than the rest of France, while some large areas in the north and west had remarkably few cases relative to their populations. No rural clusters were identified. A number of explanations for regional variations in case rates are possible, including population characteristics and case finding artifacts. Based on their results and those of other studies, the authors conclude that the strongest evidence for clustering of Creutzfeldt-Jakob disease is familial and ethnic, rather than geographic.

Africa, Northern↗
PubMed1988

Spatial and temporal analysis of disease occurrence for detection of clustering.

Data on disease occurrence often consist of the number of cases recorded in a set of regions during each of several time periods. In this paper a method of analysis of such data is proposed which allows one to distinguish and test for spatial clustering, temporal clustering, and space-time clustering of cases. Departures of case numbers from expectation are partitioned into region and time period main effects and region-by-time interactions. Spatial and temporal relationships among regions and time periods are incorporated by pooling estimates over neighborhoods. In addition to providing tests for clustering, the analysis identifies the contributions to clustering made by individual neighborhoods. Data on Creutzfeldt-Jakob disease in France are used to illustrate the approach.

Biometry↗