PubMed Health⌕ Search

Biomedical subjects

R H Pantell

Publications and source records attributed to R H Pantell.

At least 19 recordsLinked to original sources
PubMed2004

Demonstration of high-trapping efficiency and narrow energy spread in a laser-driven accelerator.

Laser-driven electron accelerators (laser linacs) offer the potential for enabling much more economical and compact devices. However, the development of practical and efficient laser linacs requires accelerating a large ensemble of electrons together ("trapping") while keeping their energy spread small. This has never been realized before for any laser acceleration system. We present here the first demonstration of high-trapping efficiency and narrow energy spread via laser acceleration. Trapping efficiencies of up to 80% and energy spreads down to 0.36% (1 sigma) were demonstrated.

Journal Article↗
PubMed2001

First staging of two laser accelerators.

Staging of two laser-driven, relativistic electron accelerators has been demonstrated for the first time in a proof-of-principle experiment, whereby two distinct and serial laser accelerators acted on an electron beam in a coherently cumulative manner. Output from a CO2 laser was split into two beams to drive two inverse free electron lasers (IFEL) separated by 2.3 m. The first IFEL served to bunch the electrons into approximately 3 fs microbunches, which were rephased with the laser wave in the second IFEL. This represents a crucial step towards the development of practical laser-driven electron accelerators.

Journal Article↗
PubMed2000

Body temperature of newborns: what is normal?

Medical records of 203 healthy full-term infants were reviewed to determine the range of axillary temperatures for newborn infants, factors that affect temperature and nursery management of infants with temperatures outside published normal ranges. The mean birth temperature was 36.5 degrees C (S.D. = 0.6 degrees C). Temperature was associated with birth weight (p<0.0005) and the presence of maternal fever (p<0.0001) but not with type of environment or time of birth. The mean temperature increased with age, rising 0.2 degrees C by 2-3 hours after birth (p<0.0001) and 0.3 degrees C by 15-20 hours (p<0.0001). Among a subset of 114 eligible neonates the mean temperature dropped 0.2 degrees C after bathing (p<0.0001). Although 17% of all temperatures measured were in the hypothermic (< or =36.3 degrees C) range, the only response recorded by nursery staff consisted of warming by modifying the environment, e.g., bundling. Blood cultures were drawn from 51 infants (25%), 43 because of maternal intrapartum antibiotic treatment for maternal fever or prolonged duration of ruptured amniotic membranes (>24 hours) and none for evaluation of abnormal temperatures. No infants had systemic infections and all were discharged in stable condition. Newborn axillary temperatures in our nursery were considerably lower than what has been previously described as "normal." Given the frequency of "hypothermia" and absence of associated illness, we believe the reference range for newborn temperatures should be expanded to include lower temperatures.

Adult↗
PubMed1999

Is the routine pelvic examination needed with the advent of urine-based screening for sexually transmitted diseases?

OBJECTIVE: To determine the most cost-effective method of screening for chlamydia and gonorrhea to prevent pelvic inflammatory disease (PID) in asymptomatic sexually active adolescent females. DESIGN: Cost-effectiveness decision analysis comparing pelvic examination with cervical screening (the current national standard) with a model of urine screening with ligase chain reaction testing for Chlamydia trachomatis and Neisseria gonorrhoeae. METHODS: Four strategies using decision analysis were compared for a potential cohort of 100000 asymptomatic sexually active young women: (1) pelvic examination screening in 100%; (2) urine screening in 100%; (3) actual predicted pelvic examination screening in 70%; and (4) actual predicted urine screening in 90%. Assumptions and costs were generated from published sources. MAIN OUTCOME MEASURES: Cases of PID prevented per year and cost to prevent a case of PID. RESULTS: A total of 1750 cases of PID would be predicted to occur per year with no screening. Strategy 1 would prevent the most cases of PID (1283) at a mean cost of $10230. Strategy 2 would prevent 1215 cases of PID at a mean cost of $5093. The marginal cost to prevent an additional case of PID by strategy 1 is $101454. Strategy 3 would prevent 898 cases of PID and 1093 cases of PID would be prevented with urine screening in strategy 4. CONCLUSION: Urine-based ligase chain reaction screening is the most cost-effective strategy to detect chlamydial and gonococcal genital infection in asymptomatic sexually active adolescent females and, owing to ease of implementation, the most likely to prevent the greatest number of cases of PID.

Adolescent↗
PubMed1997

Gender differences in physician-patient communication. Evidence from pediatric visits.

OBJECTIVE: To determine whether physician gender and patient gender influence the process of communication and parent and child satisfaction during pediatric office visits. DESIGN: Content analysis of videotaped pediatric office visits. SETTING: University-based pediatric primary care practice. SUBJECTS: Videotaped communication between 212 children, ages 4 to 14 years, parents, and physicians. Thirty-eight percent were child health supervision visits, and 62% were for the management of minor or chronic illnesses. MAIN OUTCOME MEASURES: An established coding system of physician-patient communication and measures of parent and child satisfaction with medical care. RESULTS: Female physician visits were 29% longer than those of male physicians (P < .001). Compared with male physicians, female physicians engaged in more social exchange (P < .01), more encouragement and reassurance (P < .01), more communication during the physical examination (P < .05), and more information gathering (P < .01) with children. Male and female physicians engaged in similar amounts of discussions regarding illness management. Children were more satisfied with physicians of the same gender (P < .05), while parents were more satisfied with female physicians (P < .05). CONCLUSIONS: Children communicate more with female than with male physicians and show preferences for physicians of the same gender. These findings are consistent with communication patterns in adult patients and may have a significant influence on gender disparities in health care. Efforts at improving the process and outcome of medical care should address gender differences.

Adolescent↗
PubMed1996

Health care of children and adults with acquired immunodeficiency syndrome. A population-based analysis.

OBJECTIVES: To compare the use of medical services by pediatric and adult patients with acquired immunodeficiency syndrome (AIDS) in the 6 months before and after the diagnosis of AIDS when demand for care is often high and to study the influence of human immunodeficiency virus specialty care on survival of pediatric patients. DESIGN: Retrospective analysis of Medicaid files. SETTING: New York State Medicaid Program. PATIENTS: A cohort identified as having AIDS from 1985 through 1990 and enrolled on Medicaid from birth or 1 year or more before diagnosis. Because of differing prognoses, 3 groups were studied by age at the time that AIDS was diagnosed: infants younger than 6 months, children aged 6 months to 12 years, and adults aged 13 to 60 years. MAIN OUTCOME MEASURES: Frequencies of any service use and, among users, monthly rates of services. From Cox proportional hazards models, the adjusted hazard of death for human immunodeficiency virus specialty ambulatory care. RESULTS: Nearly all infants (n = 122) were hospitalized before and after the diagnosis of AIDS was made--the most of all groups. After diagnosis, only 81% of older children (n = 612) were hospitalized vs 93% of infants and 90% of adults (n = 5602). Hospitalized children had a median of only 3.3 inpatient days per month vs 12.3 and 7.8 inpatient days for infants and adults, respectively. Of older children, 45% used the emergency department vs 33% of adults. Human immunodeficiency virus specialty care for infants and children was associated with a 40% lower risk of death after the diagnosis of AIDS. CONCLUSIONS: In this AIDS cohort, infants had the greatest use of inpatient care, and older children used the emergency department more than adults. The finding of improved survival for infants and children with human immunodeficiency virus specialty care warrants further study in more recent years.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Psychosocial problems during child health supervision visits: eliciting, then what?

An explicit goal of child health supervision visits is to gather information and provide guidance about the psychosocial problems of children and families. The purpose of this study was to determine the extent to which parents had opportunities to express psychosocial concerns and the nature of physicians' responses to these concerns during health supervision visits. The authors analyzed videotapes of child health supervision visits by 34 children aged 5-12 years to 34 pediatric and family medicine residents. Coding systems with acceptable interobserver reliability were developed to assess (1) the nature of opportunities provided to express concerns, (2) categories of psychosocial problems expressed by parents and children, and (3) the nature of physicians' responses. In 88% of the child health supervision visits, opportunities were created by the physician to discuss psychosocial concerns or were spontaneously raised by the parent or child. In half of the visits, parents or children expressed a total of 30 psychosocial concerns. Psychosocial problems raised included conduct/behavior problems (47%), insecurity (13%), family, sibling, or social problems (13%), learning difficulties (10%), somatization (7%), and other (10%). Physicians' responses to these psychosocial concerns were as follows: 17% ignored the concern; 43% asked further exploratory questions but provided no information, reassurance, or guidance; 3% reassured the parent; 27% responded with psychosocial information and/or action; 3% responded with medical information and/or action; and 7% responded with a combination of these latter two modes of actions. Pediatric residents were more likely to respond to more disruptive behavioral concerns (r = .60, P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Increasing patient knowledge, satisfaction, and involvement: randomized trial of a communication intervention.

A brief educational intervention to promote effective communication between physicians, children, and parents during pediatric office visits was designed and tested. A randomized clinical trial involving 141 children (5- to 15-year-olds) tested the effectiveness of the intervention to improve the process and outcome of medical care. The intervention was contained in three brief videotapes (one each for parents, physicians, and patients) and in accompanying written materials. Materials were designed to build skills and motivation for increased child competence and participation during pediatric medical visits. Control subjects saw health education videotapes and received materials comparable in length with those of experimental subjects. Postintervention medical visit process was analyzed using videotapes of visits. Visit outcomes, assessed with standardized instruments and interviews, included children's rapport with physicians, children's anxiety, children's preference for an active health role, children's recall of information, parents' satisfaction with the medical visit, and physician satisfaction. Results indicated that physicians in the intervention group, compared with their counterparts in the control group, more often included children in discussions of medical recommendations (50% vs 29%, t = 2.39, P less than .05); that children in the intervention group, compared with control children, recalled more medication recommendations (77% vs 47%, P less than .01) and reported greater satisfaction and preference for an active health role; and that the intervention and control groups did not differ in parent satisfaction, physician satisfaction, or child anxiety. The results suggest that a brief educational intervention administered during waiting room time can positively impact physician-child rapport and children's preference for an active role in health and their acquisition of medical information.

Adult↗
PubMed1989

Assessment of children's health status. Field test of new approaches.

The assessment of children's health status presents unique difficulties. These include parent-child differences in reports of functioning, knowledge of what constitutes age-appropriate functioning, obtainment of accurate information for child, and demonstration of the predictivity of health status measures. Recent measures (the Functional Status II-R and instruments from the RAND Health Insurance Experiment) address physical, social, and psychologic domains of children's health. The authors modified these instruments to develop short (7 and 14 items) questionnaires (RAND, FSQ) to assess child health. Scoring on these questionnaires was compared with traditional measures of illness severity and medical service utilization. The authors also evaluated coding illness-specific and general health limitations (FSQ-S and FSQ-G, respectively). Patients included the parents of 113 children with chronic illness (100 asthmatics). Measure stability was evaluated over a 6-month period in a subset of patients. Internal consistency (Cronbach's alpha) of the seven-item RAND measure was .78, the FSQ-S .78, and the FSQ-G .73 to .89 during repeated samplings over 6 months. The FSQ-S and Rand seven-item measure were moderately correlated (.47, P less than .001). The authors observed significant correlations among alternate codings of the FSQ and RAND and between the FSQ-S, FSQ-G, RAND, and severity measure with traditional indices of medical service utilization. Parents were more likely to attribute certain functional status problems (e.g., being tired) to illness than they were other problems (e.g., moodiness or interest in things). The findings demonstrate that these measures have acceptable psychometric properties and provide preliminary evidence of construct validity in a group of young children with asthma. Using general and specific measures will provide differing pictures of a child's functioning. No single measure completely taps the impact of illness as measured by a panel of traditional indicators of illness burden and medical service utilization.

Adolescent↗
PubMed1987

Measuring the impact of medical care on children.

To assess the impact of medical care on children we have developed a conceptual model based on both theoretical considerations and empirical research. Child health is viewed as the ability to participate fully in developmentally appropriate activities and requires physical, psychological, and social energy. The medical system influences health through interventions addressing these domains. Many methodologic issues are unique to the measurement of medical care processes and outcomes for children. Problems in measuring the process of medical interviews include developing systems that capture the dynamics of interactions, assess the cognitive appropriateness and metaphorical interpretation of language, and reflect the emotional impact of certain incidents. Issues that confound measurement of children's views include position bias, acquiescence response bias, and limited understanding of negatively worded items. Further, the concordance between parent and children reports or health constructs varies widely, which suggests the need to include children's reports to obtain a comprehensive view of their health.

Adolescent↗
PubMed1986

The impact of reading a clinical study on treatment decisions of physicians and residents.

The study presented here reports on the impact of newly published clinical research on physicians' decisions. Eighty-three pediatricians, pediatric residents, and family practitioners were presented with a common, potentially serious problem, an infant with a high fever, and were required to estimate the probabilities of bacteremia and of acquiring meningitis and to choose from management options. The participants then read a published scientific report addressing the risks of meningitis in febrile infants and were asked afterward to answer again the questions relating to the clinical problem. After reading the study, the participants significantly increased their probability estimates of the patient acquiring meningitis. Only 14 percent of the participants would have hospitalized the patient before reading the article, but 47 percent would have done so after reading the article. Pediatricians were more likely than family practitioners to use antibiotics after reading the article. These decisions were not based not based on logical processing of information, as there was no correlation between the physicians' estimate of the risk of meningitis and the underlying risk of bacteremia and no correlation between the participants' decisions to hospitalize or use antibiotics and their estimated risk of the patient developing meningitis. Physicians appear to have considerable difficulty in using probability data and appear to base estimates of serious disease and subsequent management on intuition rather than calculation.

California↗
PubMed1986

Parent satisfaction with children's medical care. Development, field test, and validation of a questionnaire.

Research on both adult patients and parents of pediatric patients has demonstrated that satisfaction with medical encounters predicts such important outcomes as compliance with medical regimen. The authors developed a questionnaire to measure parent satisfaction with children's medical encounters, administered it to 104 parents of pediatric patients (field trial 1), and revised it. The revised Parent Medical Interview Satisfaction Scale (P-MISS) was then tested on a new sample of parents whose medical visits were videotaped (field trial 2). On field trial 2, the P-MISS showed a high alpha reliability (0.95). The four factor-based subscales identified by field trial 1 showed high alpha reliabilities on field trial 2: physician communication with the parent (0.81); physician communication with the child (0.93); distress relief (0.85); and adherence intent (0.86). With the exception of the distress relief subscale, the subscales appear to measure distinct dimensions of satisfaction. Objective ratings of physicians' interpersonal skills to parents during medical interviews correlated significantly with parents' total satisfaction scores as well as with all four satisfaction subscale scores, providing preliminary evidence of the construct validity of the P-MISS.

Adolescent↗
PubMed1984

Chest pain in adolescents--functional consequences.

In prospectively evaluating 100 cases of adolescents with chest pain (along with two control groups), 91 were found to have recurrent chest pain; fewer than 5 had a serious organic cause. Significantly higher school absenteeism occurred in patients with either chest or abdominal pain than in patients without pain. Adolescents with chest and abdominal pain were more likely to be high users of medical services than those with no pain. Most adolescents believed that persons their age could have attacks; 44 of those with chest pain thought their symptom was due to a heart attack. The occurrence of chest pain was not influenced by an adolescent's age, sex, race, smoking status or family structure, nor was it consistently associated with depression. Chest pain is thus a common problem of adolescence that produces considerable functional impairment not attributable to serious underlying disease.

Abdomen↗