Biomedical subjects

S L Stewart

Publications and source records attributed to S L Stewart.

31 records · Page 2Linked to original sources

PubMed1997

Predictors of misclassification of Hispanic ethnicity in a population-based cancer registry.

PURPOSE: Hispanic ethnicity is often used as a category for calculating population-based rates or assessing risk of epidemiologic studies. However, ethnic misclassification can lead to false conclusions unless the extent of misclassification and the characteristics of those misclassified are understood. METHODS: This study explored determinants of ethnic misclassification in a sample of 1154 cancer cases in the San Francisco-Oakland cancer registry, where ethnic classification is based on surname or medical record report. We compared the following: correctly classified Hispanics, persons classified as Hispanic who self-identified as non-Hispanic, and persons classified as non-Hispanic who self-identified as Hispanic. RESULTS: Among men classified as Hispanic, those most likely to self-identify as non-Hispanic did not speak Spanish, had non-Spanish surnames, and were recent immigrants. Women misclassified as Hispanic did not speak Spanish or have Spanish maiden names, nor did they have mothers with Spanish maiden names. Persons who called themselves Hispanic, but were misclassified by the registry, were likely to be non-Spanish speaking college-education males. CONCLUSIONS: Researchers using ethnicity should be aware of how ethnicity was determined and how this classification may bias or confound their results.

Adult↗

PubMed1997

Formant transition duration and speech recognition in normal and hearing-impaired listeners.

Listeners with sensorineural hearing loss often have difficulty discriminating stop consonants even when the speech signals are presented at high levels. One possible explanation for this deficit is that hearing-impaired listeners cannot use the information contained in the rapid formant transitions as well as normal-hearing listeners. If this is the case, then perhaps slowing the rate of frequency change in formant transitions might assist their ability to perceive these speech sounds. In the present study, sets of consonant plus vowel (CV) syllables were synthesized corresponding to /ba, da, ga/ with formant transitions for each set ranging from 5 to 160 ms in duration. The listener's task was to identify the consonant in a three-alternative, closed-set response task. The results for normal-hearing listeners showed nearly perfect performance for transitions of 20 ms and longer, whereas the shortest transitions yielded poorer performance. A group of eight hearing-impaired listeners pure-tone averages (PTAs) ranging from 30 to 62 dB HL) was also tested. The hearing-impaired listeners tended to show poorer performance than the normals for transitions of all durations; however, the performance of a few hearing-impaired subjects was equal to that of normals for the shortest-duration transitions. A strong inverse relation was observed between degree of hearing loss and improvement in score as a function of transition duration. These results suggest that increasing the duration of formant transitions for listeners with more severe hearing losses may not provide a helpful solution to their speech recognition difficulties.

Hearing↗

PubMed1997

The consistency and concomitants of inhibition: some of the children, all of the time.

Toddlers displaying extremely inhibited behavior may be at risk for becoming socially withdrawn. However, behavioral inhibition may be a multifaceted characteristic, and its concurrent relation to toddler wariness with peers has not been examined. In this study, 108 toddlers (54 females) and their mothers were observed in novel situations involving unfamiliar settings, adults, and peers. Vagal tone, temperament, separation-reunion behavior, and maternal oversolicitousness also were assessed. There was little consistency of inhibited behavior across the 3 situations. Consistently inhibited toddlers had fearful temperaments, showed distress following maternal separation, and had mothers who were warm and controlling but unresponsive to children's cues during interaction. Toddlers with highly fearful temperaments and highly oversolicitous mothers were the most inhibited across contexts.

Child, Preschool↗

PubMed1996

NM23 gene expression in human prostatic carcinomas and benign prostatic hyperplasias: altered expression in combined androgen blockaded carcinomas.

PURPOSE: To investigate whether NM23 (nm23-H1, nm23-H2), a metastasis suppressor gene family, is a molecular marker indicative of metastatic potential of localized carcinoma of the prostate (CaP). Previously, we found decreased nm23-H2 expression correlated with an increase in stage, and here we have expanded the cohort. MATERIALS AND METHODS: Eighty prostate tissue samples from patients with CaP and benign prostatic hyperplasia (BPH) were examined by quantitative reverse transcriptase polymerase chain reaction (RT-PCR) for NM23 gene expression. Samples were grouped according to stage, grade and whether the patient received combined androgen blockade (CAB) prior to surgery. RESULTS: We could not confirm our initial results of an inverse correlation of nm23-H2 expression levels with grade. However, two significant results were found after CAB: 1) nm23-H1 expression was reduced (p = 0.003), and 2) nm23-H2 expression across stage and grade was uniformly higher (p = 0.003) than in untreated samples. CONCLUSION: NM23 appears not to be a useful molecular marker of metastatic potential in CaP. The altered gene expression after CAB may relate to a cancer cell subpopulation insensitive to apoptosis induced by hormone withdrawal.

Biomarkers, Tumor↗

PubMed1995

Effect of impact stress on microbial recovery on an agar surface.

Microbial stress due to the impaction of microorganisms onto an agar collection surface was studied experimentally. The relative recovery rates of aerosolized Pseudomonas fluorescens and Micrococcus luteus were determined as a function of the impaction velocity by using a moving agar slide impactor operating over a flow rate range from 3.8 to 40 liters/min yielding impaction velocities from 24 to 250 m/s. As a reference, the sixth stage of the Andersen Six-Stage Viable Particle Sizing Sampler was used at its operating flow rate of 28.3 liters/min (24 m/s). At a collection efficiency of close to 100% for the agar slide impactor, an increase in sampling flow rate and, therefore, in impaction velocity produced a significant decline in the percentage of microorganisms recovered. Conversely, when the collection efficiency was less than 100%, greater recovery and lower injury rates occurred. The highest relative rate of recovery (approximately 51% for P. fluorescens and approximately 62% for M. luteus) was obtained on the complete (Trypticase soy agar) medium at 40 and 24 m/s (6.4 and 3.8 liters/min), respectively. M. luteus demonstrated less damage than P. fluorescens, suggesting the hardy nature of the gram-positive strain versus that of the gram-negative microorganism. Comparison of results from the agar slide and Andersen impactors at the same sampling velocity showed that recovery and injury due to collection depends not only on the magnitude of the impaction velocity but also on the degree to which the microorganisms may be embedded in the collection medium.(ABSTRACT TRUNCATED AT 250 WORDS)

Aerosols↗

PubMed1994

Being alone, playing alone, and acting alone: distinguishing among reticence and passive and active solitude in young children.

3 forms of solitude were studied in young children--reticence (onlooker and unoccupied behavior), solitary-passive behavior (solitary-constructive and -exploratory play), and solitary-active behavior (solitary-functional and -dramatic play). 48 4-year-old children grouped in quartets of same-sex unfamiliar peers were observed in several situations. Mothers completed the Colorado Temperament Inventory. Results indicated that (1) solitary-passive, solitary-active, and reticent behaviors were nonsignificantly intercorrelated; (2) reticence was stable and associated with the demonstration of anxiety and hovering near others, whereas solitary-passive and solitary-active play were stable yet unrelated to anxiety and hovering; (3) reticence during free play was generally associated with poor performance and displays of wariness in several other social situations, while solitary-passive and -active play were not; (4) reticence was associated with maternal ratings of child shyness, while solitary-active behavior was associated with maternal ratings of impulsivity. Results are discussed in terms of the underlying mechanisms associated with reticence and passive and active withdrawal.

Anxiety↗

PubMed1993

The temporary inactivation of the red nucleus affects performance of both conditioned and unconditioned nictitating membrane responses in the rabbit.

These experiments are part of a series of studies examining the role of the red nucleus in the performance of the conditioned and unconditioned nictitating membrane reflexes in the rabbit. Specifically, the experiments test the hypothesis that the temporary inactivation of the red nucleus selectively affects the performance of the conditioned reflex. The experiments were designed to assess the effects of lidocaine and control saline microinjections on conditioned as well as unconditioned responses in both paired and unpaired trials. Rabbits were chronically implanted with cannulae through which small injecting tubes were passed stereotaxically to the red nucleus. The animals were conditioned using a delay paradigm in which a 1 kHz tone and an air puff applied to the cornea were used as the unconditioned and conditioned stimulus, respectively. Once conditioned, the effects of either lidocaine or saline injection were evaluated while alternating paired trials with unpaired trials in which only the air puff was applied. The principal finding of this study was that the amplitudes of both the conditioned and unconditioned responses were reduced following lidocaine injection into the red nucleus. The effect on the unconditioned response amplitude could not be ascribed to any interaction between the conditioned and unconditioned responses, since it also was present in the unpaired trials. The reduction in amplitude of the conditioned and unconditioned responses was shown to be correlated with changes in other characteristics of the same responses. The data suggest that the red nucleus contributes to the performance of both the conditioned and unconditioned nictitating membrane reflexes and consequently is not likely to be involved only in pathways responsible for mediating and/or storing the engram for the conditioned reflex.

Acoustic Stimulation↗

PubMed1992

Acute MI: a review of pathophysiology, treatment, and complications.

Few areas of clinical medicine have undergone advancements in the last decade as dramatic as those in the management of acute myocardial infarction (AMI). Nursing care of the AMI patient should be based on a comprehensive knowledge of the pathophysiology involved in order to intervene appropriately, understand medical therapies utilized, and anticipate complications. This article offers an in-depth review and update of the pathophysiology of AMI, current recommendations regarding management of the patient with acute infarction, and an overview of complications that still pose a threat to recovery in some patients.

Cardiovascular Agents↗

PubMed1989

Designing a competency-based orientation program for the care of cardiac surgical patients.

Orienting nurses to care for the cardiac surgical patient may require 7 to 14 days with a preceptor. Use of a competency-based orientation (CBO) program such as the one described in this article can minimize orientation time to three to five days while assuring competent practice. CBO uses a variety of learning methods and individualized instruction, focusing on the ability to perform a task or behavior correctly rather than on the ability to demonstrate knowledge. This article describes the basic components of a CBO program. Personal experience with development of such a program for the care of cardiac surgical patients in the immediate postoperative period is described. Advantages and limitations of CBO are described, as are suggestions for future research.

Cardiac Surgical Procedures↗

PubMedDate not supplied

Intrusiveness of illness and quality of life in young women with breast cancer.

Our objective was to test a theoretical model that explains quality of life as a function of the intrusiveness of illness encroaching on the different domains of one's life. The intrusiveness of illness is explained not only by disease and treatment related factors, but also by one's psychological and social resources (Devins, 1994). To investigate this issue, a sample of 336 women aged 50 and under, recently diagnosed with breast cancer were interviewed in their homes. Consistent with Devins' model, intrusiveness of illness mediated the effect of disease and treatment factors on quality of life. Contrary to his model, some treatment factors also had direct effects while social and psychological factors had only direct effects on quality of life. Neither time post-diagnosis nor type of treatment affected the psychological component of quality of life.

Adaptation, Psychological↗

PubMedDate not supplied

Smoking acquisition among adolescents and young Latinas: the role of socioenvironmental and personal factors.

This paper examined the effects of socioenvironmental and personal factors on two stages of the smoking continuum--onset of smoking and regular smoking--among a sample of 1411 Latina clients, ages 14-24, at two federally funded family planning clinics. The socioenvironmental factors included cultural indicators, smoking behavior of family and peers, and norms. The personal factors were risk-taking behaviors and intention to smoke in the future. Results showed that the indicators associated with experimentation were different than those linked with regular smoking. Socioenvironmental factors associated with the transition from never having smoked to trying cigarettes included acculturation, as measured by language and familialism, and peer smoking behavior. Among the personal factors, risk-taking behavior (past use of drugs, alcohol, and general risk attitude) and smoking intentions were correlates of experimentation. The transition from experimenter to regular smoker was associated with peer smoking behavior (P< .05) in the socioenvironmental domain and drug use and intention to smoke in the future among the personal factors (both P values <.001). Age, years of education, marital status, norms, and parental smoking did not independently predict either of the smoking outcomes. Intention to smoke was the strongest predictor of experimentation (OR = 8.3, Cl 5.87-11.60) and regular smoking (OR= 19.9, CI 12.31-29.21) and could help identify those most likely to benefit from smoking prevention and cessation interventions.

Adolescent↗

PubMedDate not supplied

Young Latinas and abortion: the role of cultural factors, reproductive behavior, and alternative roles to motherhood.

Latina women have often been portrayed as holding strong traditional family values leading to a greater propensity for rejection of contraception and abortion. Increasingly, the literature has consistently shown that Latina women use contraception effectively when available; however, much less is known about the prevalence of abortion and the factors related to its use in this population. In this article we examine Latinas' use of abortion and identify factors affecting its use among 1,207 ever-pregnant Latina women age 14-24 recruited at two federally-funded family planning clinics in the Los Angeles metropolitan area. Only a small proportion of the young women in our sample (7.5%) had ever had an induced abortion. In multivariate analysis the variables significantly associated with past abortion included less traditional attitudes about women's roles, higher gravidity, shorter periods of sexual activity, and a higher number of lifetime sexual partners. We conclude that use of abortion among Latinas is driven by role orientation and reproductive variables.

Abortion, Induced↗

PubMedDate not supplied

Radial neck fracture nonunion in children.

Radial neck nonunion in children is a rare complication of a displaced radial neck fracture. The authors conducted a retrospective review of nine cases of radial neck nonunion in an effort to identify risk factors for nonunion and to evaluate treatment options. Nine patients, average age 8.2 years, sustained displaced Salter-Harris type II fractures of the radial neck, with average angulation of 83 degrees and average displacement of 83%, and elbow dislocation or additional fracture in eight of nine patients. Initial treatment with open reduction achieved anatomical alignment of the fracture fragments in seven of the nine patients. Initial reduction was lost and radial neck nonunion developed in all patients. The nonunion was treated with observation, radial head and neck excision, or open reduction and internal fixation with bone graft, depending on the level of pain, deformity, and functional deficit. Healing of the nonunion did not necessarily lead to improvement of clinical symptoms. Severity of initial fracture displacement and inadequate fixation technique contributed to radial neck nonunion. Treatment of the nonunion should depend on the patient's pain, deformity, and functional restriction.

Child↗