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Biomedical subjects

R L Carter

Publications and source records attributed to R L Carter.

At least 73 records · Page 4Linked to original sources
PubMed1989

Effect of birth weight, race, and sex on survival of low-birth-weight infants in neonatal intensive care.

Survival for low-birth-weight infants has traditionally been analyzed by birth weight categories spanning considerable ranges of weight. We developed a finer description of survival rates to allow estimation of survival percentages for infants of any specific birth weight between 500 and 2500 gm. Our sample consisted of 16,183 infants treated in tertiary neonatal intensive care between 1980 and 1987. Their survival data were analyzed by 50 gm increments between 500 and 2500 gm, and a continuous survival curve was constructed by log linear regression methods. Mortality differences between males and females and blacks and whites were analyzed. Survival for females was higher than males between 500 and 1500 gm and higher for blacks than whites between 650 and 1500 gm. Between 1500 and 2500 gm, no significant effects of birth weight, race, or sex were observed, with survival remaining stable at approximately 95% across all combinations of variables.

Birth Weight↗
PubMed1989

Results of a prospective study evaluating the effects of mantle irradiation on pulmonary function.

Thirty patients with Stages I-III Hodgkin's disease receiving mantle irradiation were prospectively evaluated prior to therapy with spirometry, lung volumes, and tests of diffusing capacity (DLCO). Follow-up examinations were performed at 3, 6, and 12 months and then yearly. Sixteen patients had Hodgkin's disease involving the mediastinum at presentation, 10 were smokers, and 16 received either preirradiation or postirradiation chemotherapy. Mantle doses ranged between 2300 cGy and 4000 cGy (mode of 3750 cGy) given at 150 cGy to 170 cGy tumor dose per day with split-course technique. Pulmonary function test results were translated to percent change from predicted values obtained from normal standards for each age, sex, race, and height. These percent changes were then analyzed as a linear function of time. Twenty patients have been tested greater than or equal to 4 years after treatment with a median time from treatment to last pulmonary function test of 8 years. Changes over time in spirometry included an early, mild decrease in both forced vital capacity (FVC) and forced expiratory volume at 1 second (FEV1), which returned to baseline by 2 years and then gradually decreased to a 10-15% deficit as compared with predicted values at 6-10 years. Additionally, there was a very slight decrease in FEV1/FVC beginning at 1 year and gradually increasing to an 8% deficit at 6-10 years. Changes over time in lung volumes included a mild nadir of total lung capacity (TLC) and functional residual capacity (FRC) at 6 months to a year, which returned to baseline at 2-4 years and then gradually dropped to a 5-10% deficit at 6-10 years. Mean DLCO for the study group was 20% below predicted values prior to treatment and dropped to a low of 30% below predicted at 6 months following treatment, then gradually returned to baseline by 4 years and showed continued improvement to an overall deficit of approximately 10% at 6-10 years. With the exception of FEV1/FVC, the changes noted in spirometry and lung volumes were of insufficient degree to be classified as abnormal. The decrease in FEV1/FVC is indicative of a significant and progressive obstructive ventilatory defect. The effects on pulmonary function tests of smoking, the presence of mediastinal involvement by Hodgkin's disease, and exposure to chemotherapy were assessed by statistical analysis. No subsets of patients demonstrated consistent evidence of a restrictive ventilatory defect expected after irradiation.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1989

Predictive value of Apgar scores for developmental outcome in premature infants.

For more than two decades, Apgar scores have been used to predict developmental outcome in newborns. However, most studies have used full-term babies for their data base, and the predictive value of Apgar scores for low birthweight infants has remained unclear. This study was designed to provide a data base for premature infants, demonstrating to what degree Apgar scores predict developmental outcome. We tested Apgar scores alone and in combination with two other easily quantified variables, birthweight and gestational age, as predictors of risk for 256 infants weighing less than 1800 gm at birth. Although significant correlations existed between Apgar scores and Bayley Mental and Psychomotor Developmental Indices, multiple regression analyses demonstrated that these relationships were not significant independent of birthweight and gestational age. That is, after controlling for birthweight and gestational age, Apgar scores did not predict morbidity in low birthweight infants and should not be used to provide a developmental prognosis.

Apgar Score↗
PubMed1989

Expression of desmin and myoglobin in rhabdomyosarcomas and in developing skeletal muscle.

Immunohistochemical staining for desmin and myoglobin was investigated in 35 rhabdomyosarcomas from young people and in skeletal muscle from 16 human fetuses of known gestational age. Twenty-nine of the rhabdomyosarcomas expressed desmin but six undifferentiated or poorly-differentiated tumours were desmin negative. Of the desmin positive cases, most undifferentiated or poorly-differentiated sarcomas expressed desmin alone (12/35). Tumours with increasing rhabdomyoblastomic differentiation co-expressed myoglobin (9/35) and well-differentiated examples also contained cross-striations (7/35). Skeletal muscle from fetuses aged 8 weeks or less consisted mainly of primitive desmin negative round cells. As the cells began to differentiate they quickly expressed desmin and, at approximately 10 weeks, myoglobin was expressed and cross-striations were seen. The combined results strengthen the view that desmin (within a strictly defined context of round cell tumours in young people) is a reliable marker for rhabdomyoblastic differentiation. Support is also given to the notion that very primitive rhabdomyosarcomas may be desmin-negative, although the difficulties of establishing firm diagnoses for some of these tumours is emphasized.

Adolescent↗
PubMed1989

Granulocytic sarcoma: misleading immunohistological staining with MT1 and S100 protein antibodies.

Tissue from two patients with granulocytic sarcomas stained positively for MT1 and S100 protein antibodies; both of these cases presented considerable clinical and histological diagnostic difficulties until acute myeloblastic leukaemia spread to the bone marrow. Tissues from a further eight patients with granulocytic sarcoma were also examined retrospectively. Seven of them stained for MT1 and four for S100 protein but the traditional histological markers for myeloid cells--chloroacetate esterase and lysosyme--often stained only weakly and focally. This pattern of staining should raise the possibility of a granulocytic sarcoma in otherwise problematic cases.

Adult↗
PubMed1989

Cyclooxygenase blockers inhibit ethanol-induced pulmonary vasoconstriction in lambs.

We investigated the mechanism of ethanol-induced pulmonary vasoconstriction in lambs, by a pharmacological approach. We chronically instrumented 28 lambs to determine whether phentolamine (alpha-block), propranolol (beta-block), promethazine and cimetidine (H1- and H2-block), high-dose indomethacin, or low- and high-dose meclofenamate (cyclooxygenase block) altered the vasoconstriction. Ethanol alone increased pulmonary vascular resistance from 0.14 to 0.49 Torr.ml-1.kg-1.min (U). Only indomethacin (7-8 mg/kg po) and high-dose meclofenamate (7-8 mg/kg iv) abolished the pulmonary vascular response to ethanol infusion. Pulmonary vascular resistance was 0.14 U after ethanol plus indomethacin and was 0.2 U after ethanol plus high-dose meclofenamate (P = NS vs. base line). Low-dose meclofenamate (2 mg/kg) attenuated the vasoconstrictor response. Systemic vascular resistance increased moderately after ethanol and had a similar pattern of inhibition by cyclooxygenase blockade. Cardiac output and heart rate decreased nearly significantly after ethanol (P less than 0.06), a tendency that was also ablated by cyclooxygenase inhibition. Thus the acute cardiocirculatory response to ethanol involves an intact prostaglandin synthase system in lambs. To our knowledge, these data are the first documentation that cyclooxygenase enzyme blockade can eliminate the acute cardiac and vascular effects of ethanol in a whole-animal system.

Adrenergic alpha-Antagonists↗
PubMed1989

Chloralose alters both basal hemodynamics and cardiovascular responses to alveolar hypoxia in chronically instrumented, spontaneously breathing lambs.

We studied the effects of chloralose anesthesia on the basal hemodynamic state and on the cardiovascular response to alveolar hypoxia in chronically instrumented, spontaneously breathing lambs, compared with responses to the saline vehicle. Chloralose significantly increased heart rate (23%), mean systemic arterial pressure (11%), systemic vascular resistance (21%), mean pulmonary arterial pressure (23%), and pulmonary vascular resistance (46%) (n = 30, p less than 0.05, ANOVA). These changes were unrelated to baseline tone of the circulation, cardiac output, mean left atrial pressure, or physiologically important changes in arterial blood gas tensions. In addition, chloralose-treated lambs had increased heart rate, systemic vascular resistance, and pulmonary vascular resistance compared to controls during alveolar hypoxia (13-15% FiO2). Importantly, chloralose-treated lambs did not increase their cardiac output during alveolar hypoxia as did control lambs. During hypoxia, systemic vascular resistance remained elevated in chloralose-treated lambs, but declined in control lambs. Chloralose has been recommended as an ideal anesthetic agent for cardiovascular experimentation. Our data suggest that chloralose-induced alterations in basal hemodynamics and in cardiovascular responses to alveolar hypoxia represent an uncontrolled variable in acute experimental studies. Complex cardiovascular alterations caused by anesthesia should be considered in experimental design.

Animals↗
PubMed1988

Clinical and pathological study of dysphagia conservatively managed in patients with advanced malignant disease.

A series of patients with dysphagia associated with terminal malignant disease is presented. 33 patients had clinical evidence of organic dysphagia associated with tumours of the upper aerodigestive tract. Over 80% of this group who underwent necropsy had locally obstructive lesions. Conservative treatment alone led to amelioration of dysphagia in approximately 60% of patients.

Aged↗
PubMed1988

Macromolecular osteolytic factor synthesised by squamous carcinoma cell lines from the head and neck in vitro is interleukin 1.

Three human cell lines derived from oro-pharyngeal squamous cell carcinomas of the head were investigated for bone-resorbing activity in vitro. Culture media from all three spontaneously produced a non-dialysable osteolytic factor with activity in three in vitro assays for interleukin 1 (IL1), viz. the lymphocyte activating factor (LAF) assay, stimulation of collagenase synthesis by articular chondrocytes, and stimulation of prostaglandin E2 synthesis by fibroblasts. Addition of anti-human IL1 antibody to the culture media abolished all the bone-resorbing activity. Fractionation of the cell culture media by high performance liquid chromatography (HPLC) showed a single peak of activity in the chondrocyte assay with an apparent mol.wt of 15-17,000. This co-eluted with activity in a preparation of IL1 from rat peritoneal macrophage cultures. These results indicate that IL1 is responsible for the prostaglandin-independent bone resorbing activity synthesised by these cells in vitro, and may contribute to the bone destruction associated with the tumour.

Bone Resorption↗
PubMed1988

Carcinogenicity of chemicals: the weight of evidence.

1. The evidence discussed here is derived from epidemiology, long-term bioassays in laboratory animals, and predictive short-term tests. 2. Epidemiological data are obtained directly from human studies and are most compelling when they demonstrate a large relative risk and a clear dose-response in association with a distinctive tumour type. Exposure to a suspected carcinogen and the doses involved are, however, often difficult to determine, and the most sophisticated epidemiological methods are relatively insensitive. There are no epidemiological data for most occupational/environmental chemicals. 3. Long-term bioassays can present major problems in design, interpretation and extrapolation. Particular difficulties are associated with the planning of appropriate dose levels and the occurrence of certain tumours at high incidence in both control and test groups. Results from animal bioassays set priorities for concern and action but they cannot be reliably used for quantitative assessment of human risk. 4. Evidence of potential carcinogenicity derived from short-term predictive tests, involving a wide variety of systems with diverse end-points, is increasingly important. Emphasis is placed on the need for more in vivo procedures with a broadening of the scope of somatic cell targets.

Animals↗
PubMed1988

Effects of intimacy of therapist's self-disclosure and formality on perceptions of credibility in an initial interview.

A therapist's expertness, trustworthiness, empathy, and attractiveness were evaluated by 300 subjects after viewing a 5-min. videotape of a therapist-client interaction. Therapist's level of self-disclosure and formality were the independent variables. Ratings of trustworthiness were highest when the therapist was informal. Therapist's high disclosure of depression yielded decreased ratings of attractiveness, empathy, and expertness in comparison with no disclosure by the therapist.

Adult↗
PubMed1988

Developmental intervention program for high-risk premature infants: effects on development and parent-infant interactions.

Developmental follow-up studies have documented that low birth weight infants are at high risk for mental and physical disabilities, despite recent advances in neonatal intensive care. Moreover, parent-infant bonding is hampered by the barriers created by technical equipment. This study evaluated a program of hospital and home-based developmental interventions designed to enhance the development of high-risk, preterm infants and the quality of communication between infants and their caregivers. Treatment and contrast groups consisted of 41 premature infants weighing less than 1800 g at birth. Treatment took a preventive approach, consisting of daily multimodal interventions in-hospital and twice-monthly interventions by child development specialists in the child's home, through 12 months adjusted age. Infants in the contrast group received traditional, remedially oriented care. The Bayley Scales of Infant Development were used to measure mental and psychomotor development, and the Greenspan-Lieberman Observations System (GLOS) was used to analyze the behavioral characteristics of infant-caregiver interactions. Developmental interventions had positive, significant effects on mental development and on the quality of caregiver-infant interactions. Changes in mental development were not independent of changes in the GLOS.

Cognition↗