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Biomedical subjects

B Lester

Publications and source records attributed to B Lester.

32 records · Page 2Linked to original sources
PubMed1993

The social context of HIV transmission in the African-American community.

The concept of acquired immune deficiency syndrome (AIDS) as a behavioral problem, and the emphasis placed by researchers on race and ethnicity as "risk factors," have led to research focused on the "risk behaviors" of historically oppressed groups and a continuing social policy thrust that "blames the victim." Disproportionate numbers of AIDS cases have been reported among African Americans, and these cases are not evenly distributed throughout the nation. This geographical variation and distribution of AIDS among African Americans suggests that there are forces in society that impact African-American communities in differential ways. A review of alternate models presented in the scientific literature reveals that some attention is being given to reconceptualizing AIDS as a disease to be understood within the context of factors that affect the African-American community, rather than as a problem of personal behavior. The current status of "contextual approaches" found in the health and social science literature over a 5-year period (1987 to 1992) was assessed. Literature surveyed includes studies from the fields of social epidemiology, public health, and social science that address the issue of AIDS in the African-American community from a contextual perspective--that is, studies that seek to explain key issues within a framework that allows a "community-in-environment" analysis, as opposed to a behavioral perspective. Analysis of these contextual approaches indicates that dynamics external to individuals must be clarified to better understand the disparate pattern of AIDS among African Americans and whites.

Black or African American↗
PubMed1989

Assessment of infant cry variability in high-risk infants.

Two studies were conducted to determine the relationship between variability in acoustic features of the infant cry and medical risk factors. In study 1, 3 groups of preterm infants (healthy, sick and CNS pathology) were compared with term infants at 40 weeks gestational age. The cry was analyzed by computer. The coefficient of variability of cry amplitude and the formant features of the cry differed among the groups of preterm infants. In study 2, 3 groups of term infants at low, moderate and high levels of hyperbilirubinemia were compared on the cry measures. More variability in the formant features of the cry was found in infants with higher levels of bilirubin. The correlation between the coefficient of variation in the cry formants and level of bilirubin was statistically significant. These two studies suggest that variability in the acoustic features of the cry relate to the medical status of the infant and may provide a measure of neurophysiological integrity.

Acoustics↗
PubMed1989

Abnormal brain-stem function (brain-stem auditory evoked response) correlates with acoustic cry features in term infants with hyperbilirubinemia.

We hypothesized that changes in brain-stem auditory evoked responses related to bilirubin would be associated with changes in cry because of the anatomic proximity in the brain stem of cranial nerves 8 (auditory) and 9 to 12 (vagal complex, which controls cry). Brain-stem auditory evoked responses and computerized cry analysis were used to study the concurrent effects of moderate hyperbilirubinemia on auditory function and cry. Fifty term infants were divided equally into two groups on the basis of serum bilirubin concentrations: low (less than 8 mg/dl; 136) mumol/L and moderate (10 to 20 mg/dl, 170 to 342 mumol/L). Forty-three infants had successful tracings of brain-stem auditory evoked responses recorded with a Cadwell model 5200A evoked response unit during two successive trials, and a cry recording of each infant was analyzed by computer. The moderate serum bilirubin group had an increase in percent cry phonation (p less than 0.02) and an increase in the variability of the first formant (p less than 0.04) in comparison with the low serum bilirubin group. Serum bilirubin values correlated positively with brain-stem conduction time (r = 0.36, p less than 0.01), percent phonation (r = 0.42, p less than 0.004), and variability of the first formant (r = 0.39, p less than 0.02). Percent phonation, the voiced component produced by increased neural control, correlated with the interpeak of waves latencies I to III (r = 0.32, p less than 0.03) and brain-stem conduction time (wave I to V) (r = 0.35, p less than 0.01). We conclude that hyperbilirubinemia affects adjoining areas of the brain stem that control hearing and cry production.

Brain Stem↗
PubMed1988

Infants of azotemic mothers: a report of three live births.

Women with severe renal failure rarely conceive, and when they do become pregnant these women often deliver prematurely. The clinical course of mothers with renal failure has been described, but little attention has been given to the offspring. In this report, we provide data on three infants born prematurely to mothers either on dialysis or with severe renal failure. The infants were the appropriate size for gestational age and demonstrated no obvious physical abnormalities. Laboratory data, including renal function, was also within normal limits. Renal size in the two infants studied by ultrasound was near or above the 95th percentile when corrected for gestational age. The premature birth appeared to be a function of maternal complications rather than a primary in utero growth disturbance.

Adolescent↗
PubMed1987

The acutely injured wrist. An anatomic basis for operative treatment.

Rational guidelines are provided for the early operative treatment of the severely injured wrist. The prominent anatomic features of the wrist as well as clinically relevant kinematics and pathomechanics are reviewed. Diagnostic and operative techniques applicable to acute injury are described. The authors point out that while the concept of prompt restoration of normal anatomic relationships in the acutely injured wrist may appear to be simple, the clinical application of the concept is quite difficult. However, an accurate diagnosis along with early meticulous surgical intervention will generally lead to a good result.

Biomechanical Phenomena↗
PubMed1986

Biochemical regulation of adenylate cyclase in murine melanoma clones with different metastatic properties.

The regulation of adenylate cyclase in murine melanoma tumor cell clones with different metastatic capacities has been studied in intact cells and isolated membrane preparations. Analysis of the responses of intact cells from a number of B16 melanoma clones revealed that treatment with melanocyte-stimulating hormone (MSH) or the diterpene, forskolin, produced significantly greater accumulation of intracellular cyclic adenosine 3',5' monophosphate (cAMP) in strongly metastatic clones than in weakly metastatic tumor cell clones. In contrast, in isolated membranes from the same panel of clones, the extent of activation by forskolin but not by MSH correlated with metastatic capacity. Sodium fluoride and 5'-guanyl-beta-gamma-imidodiphosphate [Gpp(NH)p] also stimulated adenylate cyclase in isolated membranes but the extent of activation did not correlate with the metastatic behavior of the donor cells. A combination of forskolin and Gpp(NH)p proved to be a sensitive prospective indicator for identifying differences in the metastatic capabilities of individual B16 melanoma clones. Adenylate cyclase in membrane preparations from strongly metastatic B16 clones displayed synergistic activation but stimulation of the enzyme from weakly metastatic clones was less than additive. To test the generality of these findings, similar investigations were performed on B16-BL6 melanoma cells, a highly invasive subline of the B16 melanoma, and the K1735, an ultraviolet-light-induced murine melanoma arising in a different mouse strain (C3H). Consistent with their high metastatic potential, clones derived from the B16-BL6 melanoma displayed elevated levels of hormonally-stimulated adenylate cyclase, thereby confirming, for this tumor system, a close association between hormonal responsiveness and metastatic capacity. In contrast, K1735 melanoma cell clones exhibited significant interclonal variation in adenylate cyclase activity and metastatic performance, but no consistent relationship between the two traits was detected. Differences in the regulation and/or the intrinsic catalytic capacity of adenylate cyclase may account, at least in part, for the variation in hormonal responsiveness observed among B16 clones with distinct metastatic properties and suggest that cAMP-dependent molecular processes may be required for the expression of B16 melanoma experimental metastatic potential.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenylyl Cyclases↗
PubMedDate not supplied

Experimental metastasis correlates with cyclic AMP accumulation in B16 melanoma clones.

Metastasis is a complex process whereby tumour cells from a primary neoplastic growth disseminate throughout the body and establish secondary tumour foci in distant organs. Biochemical traits associated with, or essential for, the expression of the metastatic phenotype have not yet been identified. In the course of examining stimulation of the B16 murine melanoma adenylate cyclase by melanocyte-stimulating hormone (MSH) and by the diterpene forskolin, we noted that tumour cell clones isolated from common parent cell populations differed widely in their responses to these agonists. We report here that the accumulation of cyclic AMP induced by MSH or forskolin shows a strong positive correlation with the ability of B16 melanoma clones to form pulmonary tumour colonies when injected intravenously (i.v.) into syngeneic mice ('experimental metastasis'). In parallel in vitro analyses of cyclic AMP metabolism and in vivo assays of experimental metastasis using replicate cell preparations, highly metastatic tumour cell clones consistently show greater than a 30-fold increase in cellular cyclic AMP when exposed to MSH or forskolin. By contrast, clones with limited metastatic abilities respond to the same agonists with only a two- to threefold increase in cellular cyclic AMP. These data suggest that cyclic AMP metabolism is linked with biochemical pathways that are responsible for the formation of experimental metastasis by the B16 melanoma.

Animals↗
PubMedDate not supplied

Patient satisfaction: what works in radiology.

In recent years, patient satisfaction in healthcare has been criticized as much as poor customer satisfaction in other industries. Many times, the financial problems that exist are used as an excuse for poor patient satisfaction. This excuse can never justify treating a patient rudely or with disrespect. Patients are the essence of why we exist in radiology. Their increasing scrutiny--over the care they receive and the services we provide--will significantly impact the future of healthcare in the United States. Healthcare employees need to focus on teamwork and respect for patients as well as co-workers as foundations for improving patient satisfaction. True leaders will set the mood of the healthcare facility by "practicing what they preach." Some basic rules to follow to improve customer satisfaction include listening to employees, recognizing exceptional behavior, correcting negative behavior, communicating expectations to employees and listening to patients' needs and concerns. The secret to successful patient satisfaction is not only exceeding the expectations of our patients, but also exceeding the expectations of our employees who take care of patients.

Guidelines as Topic↗
PubMedDate not supplied

An instrument for the measurement of infant-adult synchrony.

The Dyadic Mini Code (DMC) is designed to measure levels of synchrony in early infant-adult interaction. Based on important components of synchronous interaction reported in the literature, the instrument consists of six items, a total score, and a summary rating. Videotapes of 38 term and preterm mother-infant pairs were studied to establish reliability and validity of the tool. Interrater reliability was determined using Cohen's kappa and percent of agreement; kappa was .86 for the total score and ranged from .63 to .92 for each of the six items. A discrimination index, applied to each item, indicated that four items are good predictors of the final rating and two require further testing. Dyadic Mini Code summary ratings compared to mean coherence values computed from Monadic Phase Scale (Tronick, Als, & Brazelton, 1980) scores on the same data yielded moderate concurrent validity; point bi-serial analysis, rpb = .488, p less than .01; and chi 2 = 4.878, df = 1, Fisher's exact test (1-tail) = p less than .05. Construct validity was demonstrated by finding that the instrument discriminated between preterm and term dyads according to expected differences, chi 2 = 4.071, df = 1, Fisher's exact test (1-tail) = p less than .05. Further refinement of the DMC is indicated.

Child Behavior↗
PubMedDate not supplied

Rhythmic patterning in mother-newborn interaction.

Face-to-face, dyadic interaction in term and preterm mother-newborn pairs was examined for a rhythmic pattern at 40 weeks gestational age. Three-minute interaction episodes for each mother-infant pair were recorded on videotape and scored with a dyadic code graded along a dimension of disengagement-engagement. Spectral analysis was used to analyze the data for rhythmicity. A reliable rhythmic structure was found in all dyadic interactions. No significant difference was evident between term and preterm dyads. The findings provide quantitative evidence of rhythmic patterning in dyadic interaction from birth for term pairs and as early as 40 weeks gestation for preterm pairs, which is much earlier than previously reported in the literature. The Dyadic Interaction Code, a new tool for studying the interaction process over time, is described, and a recently reported method of analysis (spectral analysis) for interaction data is applied to mother-newborn behavioral data.

Adolescent↗