Search PubMed⌕ Search

Biomedical subjects

L R Smith

Publications and source records attributed to L R Smith.

At least 19 recordsLinked to original sources
PubMed1999

A prospective, multidisciplinary evaluation of premenopausal women with iron-deficiency anemia.

OBJECTIVE: The cause of iron deficiency anemia (IDA) in premenopausal women is often presumed to be menstrual blood loss. The purpose of this study was to determine the diagnostic value of a comprehensive gynecological and gastrointestinal evaluation in premenopausal women with IDA. METHODS: Nineteen premenopausal, nonpregnant women older than 18 yr of age with IDA defined by a hemoglobin < 12 gm/dl with serum ferritin < 10 ng/ml participated in the study. Evaluations included directed history and physical examination by a specialist in gynecology and a subspecialist in gastroenterology, esophagogastroduodenoscopy, colonoscopy, upper gastrointestinal radiography with small bowel follow-through, antiendomysial antibody, and fecal occult blood tests. RESULTS: Seven of 19 (37%) premenopausal women with IDA were diagnosed to have a gynecological cause of anemia by a specialist in that field. Although only four of these seven patients had digestive complaints, all but one (86%) were discovered to have gastrointestinal disease by upper endoscopy; findings were duodenal ulcer and Helicobacter pylori (H. pylori) gastritis (one), esophagitis and H. pylori gastritis (one), erosive esophagitis (one), gastric arteriovenous malformations (one), and nodular/erosive H. pylori gastritis (two). Fecal occult blood testing was positive in only two (29%) subjects; upper endoscopy revealed erosive esophagitis and gastric arteriovenous malformations. Twelve of the 19 (63%) premenopausal women with IDA were not diagnosed to have a gynecological source of anemia by a specialist in that field. Fecal occult blood testing was negative among all women tested and the only digestive complaint was heartburn (pyrosis) in seven. Each was identified to have esophagitis, duodenal ulcer, or gastritis by upper endoscopy. Colonoscopic examination of the 12 subjects without gynecologic etiology for IDA revealed pan colitis (one), diverticulosis (one), diverticulosis and melanosis coli (one), hyperplastic polyps (one), and nodular lymphoid aggregates (one). CONCLUSIONS: Significant upper gastrointestinal disease is identifiable among most premenopausal women with IDA (18 of 19 or 95%), even when careful evaluation by a specialist in gynecology suggests a gynecological source. Upper endoscopy should be considered in the evaluation of all premenopausal women with IDA expressing digestive complaints or in those with IDA refractory to iron supplementation. Lower endoscopic examination may be reserved for those women with symptoms or signs suggestive of colorectal disorders.

Adult↗
PubMed1997

Risk stratification for adverse economic outcomes in cardiac surgery.

BACKGROUND: Recent emphasis on cost-containment in the health-care environment has focused attention on the cost of medical procedures. Selection of the appropriate treatment for coronary artery disease is of increasing concern. Coronary artery bypass grafting is common and very expensive, and this procedure will continue to be examined closely by reimbursement systems, particularly with regard to the lower initial cost of coronary angioplasty as a competing therapy. METHODS: Duke University Medical Center has a sophisticated accounting system that enables individual cost components to be identified, facilitates prospective analysis of cost/benefit, and aids allocation of limited hospital resources. In 1996, 1,114 coronary artery bypass procedures were performed at Duke. Preoperative patient characteristics were also analyzed in an attempt to predict risk factors for increased cost. RESULTS: The median cost for these procedures was $20,682, excluding professional fees. Sixty percent of the costs were directly associated with patient care, and the other 40% were accounted for by indirect costs to support patient care. The most significant preoperative predictor of increased postoperative cost was the mortality estimate. If this variable was excluded from the analysis, other variables (for example, ejection fraction, age, identity of the surgeon, and congestive heart failure) were all related to increased costs. CONCLUSIONS: Predicting costs based on preoperative variables offers the potential to reduce total costs through case-management strategies and aids in negotiating a risk-shared contract. However, cost reduction in routine care will have more financial impact than cost reduction by patient selection.

Aged↗
PubMed1997

The effect of ordinances requiring smoke-free restaurants and bars on revenues: a follow-up.

OBJECTIVES: The purpose of this study was to extend an earlier evaluation of the economic effects of ordinances requiring smoke-free restaurants and bars. METHODS: Sales tax data for 15 cities with smoke-free restaurant ordinances, 5 cities and 2 counties with smoke-free bar ordinances, and matched comparison locations were analyzed by multiple regression, including time and a dummy variable for the ordinance. RESULTS: Ordinances had no significant effect on the fraction of total retail sales that went to eating and drinking places or on the ratio between sales in communities with ordinances and sales in comparison communities. Ordinances requiring smoke-free bars had no significant effect on the fraction of revenues going to eating and drinking places that serve all types of liquor. CONCLUSIONS: Smoke-free ordinances do not adversely affect either restaurant or bar sales.

California↗
PubMed1997

Language arts achievement level, attitude survey format, and adolescents' attitudes towards reading.

The joint effects of student achievement level and attitude survey format upon attitudes toward reading were investigated. Sixth-grade students completed reading attitude surveys involving a standard Likert-type format or one involving pictures of the comic strip character, Garfield. The survey items were identical for both formats; only the presentation format was varied. There was no significant main effect on attitude responses due to achievement level, but the main effect due to survey format was significant, with the Likert-type format producing significantly higher attitude responses than the Garfield format. The interaction between achievement level and format also was significant, with above average students and average students giving higher attitude responses than did below average students when the Garfield format was used. When the Likert-type format was used, average students and below average students gave higher attitude responses than did above average students. The results imply that attitude responses of adolescents can be manipulated by varying the format of the survey.

Achievement↗
PubMed1997

Persistence of T-cell clones in psoriatic lesions.

BACKGROUND: We previously demonstrated a clonal dominance in the V beta 13.1 messages isolated from the lesional CD8+ T cells of psoriasis vulgaris, which suggested an interaction of V beta 13.1+ CD8+ T cells with skin antigens. OBJECTIVES: To determine whether the clonality observed accurately reflected a clonal population of infiltrating T cells or was skewed by an overabundance of messages from a small number of cells, and to extend our study of V beta gene usage by lesional CD8+ T cells to 9 new patients. DESIGN: Case study. SETTING: Patients were enrolled at the Psoriasis Research Institute in Palo Alto, Calif, and samples were analyzed at The Immune Response Corporation in Carlsbad, Calif. MAIN OUTCOME MEASURES: For the 2 previous patients, skin samples were sorted directly for V beta 13.1+ T cells, for which the T-cell receptors were sequenced. For the 9 new patients, CD8+ T cells were sorted and their T-cell receptor V beta gene usage measured using semiquantitative polymerase chain reaction with V beta-specific primers. RESULTS: The directly sorted V beta 13.1+ T cells exhibited clonal dominance in both patients. The dominant V beta 13.1 clone in each patient was the same as that found in the previous 2 biopsy specimens for which CD8+ T cells were sorted. Additionally, in 8 of the 9 new patients examined, we again found a preferential usage of V beta 3 and/or V beta 13.1 genes by the lesional CD8+ T cells. CONCLUSIONS: The clonality, which was found in the V beta messages of the sorted CD8+ T cells, accurately reflects the dominance of these clones in the infiltrating T cells. Moreover, the persistence in the same patient of the same clone for as long as 15 months and the overrepresentation of V beta 3 and/or V beta 13.1 in lesional CD8+ T cells in the new patients examined support the pathogenic role of T cells bearing these V betas.

Adult↗
PubMed1996

Multicenter preoperative stroke risk index for patients undergoing coronary artery bypass graft surgery. Multicenter Study of Perioperative Ischemia (McSPI) Research Group.

BACKGROUND: The paradox of present cardiac surgery is that the more elderly and debilitated patients benefit most from cardiac surgery compared with medical therapy, yet they sustain greater overall risk for morbidity and mortality after cardiac surgery. The goal of the present study was to develop a preoperative index predicting major perioperative neurological events in patients undergoing coronary artery bypass graft surgery. METHODS AND RESULTS: As part of a prospective, multicenter, observational study (McSPI Research Group), we enrolled 2417 patients at 24 academic medical centers in the United States. Patients who died intraoperatively or had concomitant open-heart procedures were excluded from analysis, resulting in a total of 2107 for analysis. Sixty-eight patients (3.2%) developed adverse neurological events, defined as cerebrovascular accident, transient ischemic attack (TIA), or persistent coma. Bivariate analysis was applied to determine associations between preoperative variables and neurological events. Significant bivariate predictors were identified then logically grouped, and for each cluster, a score was calculated based on principal components. Key predictor variables were age, history of previous neurological disease, diabetes, history of vascular disease, previous coronary artery surgery, unstable angina, and history of pulmonary disease, the coefficients for which were used to develop a preoperative stroke risk index that was validated by bootstrap (c-index = 0.778). Stroke risk could then be determined for each patient, calculating a patient's risk for stroke within 95% confidence intervals. CONCLUSIONS: With the McSPI stroke risk index developed in this study, neurological risk can be estimated, and the most appropriate group for perioperative therapy can be identified. Further refinement and validation of this index, however, are necessary and are under way in current studies.

Adult↗
PubMed1996

Defining neuropsychological dysfunction after coronary artery bypass grafting.

BACKGROUND: Despite the large body of literature documenting the presence of cognitive decline after coronary artery bypass grafting, there is little consensus as to the frequency and extent of cognitive impairment. One potential reason for this lack of agreement is the absence of uniform criteria for assessing cognitive decline. METHODS: Two hundred thirty-two patients underwent cognitive testing the day before operation and were examined before discharge, and at 6 weeks and 6 months after grafting. For comparative purposes, five different sets of criteria were used to define cognitive decline. RESULTS: There was little agreement between the criteria as to which patients declined at each test period. The incidence of decline ranged from 66% to 15.3% before discharge, 34% to 1.1% at 6 weeks, and 19.4% to 3.4% at 6 months. CONCLUSIONS: A large variation in reported incidence of cognitive decline after coronary artery bypass grafting can be attributed to the different criteria used to define cognitive impairment.

Aged↗
PubMed1996

A comparison of topical agents to relieve nipple pain and enhance breastfeeding.

BACKGROUND: Nipple soreness is one reason why breastfeeding women wean their infants. This study examined the effectiveness of three topical agents--USP-modified lanolin, warm water compresses, and expressed breast milk with air drying--in alleviating nipple pain, and if early predictors of breastfeeding at six weeks could be determined. METHODS: One hundred seventy-seven breastfeeding, primiparous women were randomly assigned to one of four groups. All women received education about breastfeeding technique. Numeric rating scales were used to discriminate levels of pain intensity, pain affect, and strength of sucking on day 1. Participants were interviewed by telephone on postpartum days 4, 7, and 14, and during week 6 using the same scales. RESULTS: No significant differences were found among groups for pain intensity, pain affect, or duration of breastfeeding. Results of a logistic regression indicated that older mothers and those who were exclusively breastfeeding (no supplemental feeding) were most likely to be breastfeeding six weeks postpartum. Raw scores supported the use of warm compresses. CONCLUSION: Further investigation is required into ways of supporting young mothers and how caregivers provide support to breastfeeding mothers in the early weeks after childbirth.

Administration, Cutaneous↗
PubMed1995

CD8+ T-cells in psoriatic lesions preferentially use T-cell receptors V beta 3 and/or V beta 13.1 genes.

Restricted T-cell receptor V beta gene use in animal models of autoimmune disease has led to the development of strategies to treat autoimmune disease by targeting the T-cell receptors of the pathogenic T-cells. Restricted T-cell receptor gene use has been noted in human autoimmune diseases such as rheumatoid arthritis and multiple sclerosis. We report here the finding of restricted T-cell receptor gene use in psoriasis vulgaris, as well. Our results show an elevated skin (over PBL) expression of V beta 3 and/or V beta 13.1 messages in the CD8+ T-cells in a majority of patients studied. CDR3 sequence analysis on these two V beta s from the skin demonstrated monoclonality or marked oligoclonality. A second biopsy performed 3.5 to 8 months later in four patients, at the same or different lesions, again revealed an elevated V beta 3 and/or V beta 13.1 expression and clonality. Moreover, in three of the four patients, the same TcR V beta CDR3 rearrangement was found in both biopsies, although there was no V beta CDR3 homology noted between patients. In two patients in which V beta 3 and/or V beta 13.1 was not elevated in the CD8+ T-cell population, an increase in V beta 17 gene use and clonality was found. The persistence of V beta 3- and/or V beta 13.1-bearing CD8+ T-cells in lesions that did not undergo resolution suggests their role as effector cells rather than as regulatory cells. The effector function of these CD8+ T-cells is further supported by the clonality of TcR V beta sequence data, which indicates they are recruited and expanded in situ. The V beta s identified in this study are candidate targets for selective immunotherapeutic intervention in psoriasis.

Amino Acid Sequence↗
PubMed1995

Defining the relationship of oxygen delivery and consumption: use of biologic system models.

To determine the most appropriate mathematical description of the relationship between oxygen consumption and oxygen delivery, we compared the statistical validity of a piecewise linear model to two different biologic system models--Michaelis-Menten (MM) kinetics (used for enzyme systems) and the exponential dose-response relationship (used to describe drug administration and induced response). Nine rabbits underwent five incremental steps of normovolemic hemodilution to progressively decrease DO2. VO2 was measured concurrently by a metabolic gas monitor. All three models (piecewise linear, Michaelis-Menten, and exponential) provided a very close population curve fit to the data points (r2 = 0.88, 0.91, and 0.92). However, there were significant differences in maximum predicted VO2 (VO2max)--6.8, 9.9, 7.2 ml O2.kg-1.min-1 (P < 0.0002)--and a wide range in the model-specific parameters for individual rabbits (critical DO2 6.5-11.8 ml O2.kg-1.min-1, Km 4.2-11.4 ml O2.kg-1.min-1, and kappa 0.12-0.23 ml O2-1.kg.min). In the curvilinear models, average and population parameters were not significantly different. However, in the piecewise linear model, population critical DO2 (10.9 ml O2.kg-1.min-1) was 30% more than the average critical DO2 (8.4 ml O2.kg-1.min-1) for the nine rabbits (P < 0.005). VO2max values predicted by the piecewise linear and exponential dose-response model were more consistent with those in previous publications than was the higher VO2max predicted by the MM model. The difference in the average versus population critical DO2 in the piecewise linear model meant that population modeling was inaccurate because it yielded a critical DO2 higher than that demonstrated by eight of nine individual rabbits.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Predictors of cognitive decline after cardiac operation.

Despite major advances in cardiopulmonary bypass technology, surgical techniques, and anesthesia management, central nervous system complications remain a common problem after cardiopulmonary bypass. The etiology of neuropsychologic dysfunction after cardiopulmonary bypass remains unresolved and is probably multifactorial. Demographic predictors of cognitive decline include age and years of education; perioperative factors including number of cerebral emboli, temperature, mean arterial pressure, and jugular bulb oxygen saturation have varying predictive power. Recent data suggest a genetic predisposition for cognitive decline after cardiac surgery in patients possessing the apolipoprotein E epsilon-4 allele, known to be associated with late-onset and sporadic forms of Alzheimer's disease. Predicting patients at risk for cognitive decline allows the possibility of many important interventions. Predictive power and weapons to reduce cellular injury associated with neurologic insults lend hope of a future ability to markedly decrease the impact of cardiopulmonary bypass on short-term and long-term neurologic, cognitive, and quality-of-life outcomes.

Age Factors↗
PubMed1995

In-hospital and long-term outcome after porcine tricuspid valve replacement.

Porcine bioprostheses are often used for tricuspid valve replacement, yet the long-term outcome after this procedure is not well documented. Therefore, the records of 129 patients undergoing tricuspid valve replacement with Carpentier-Edwards (n = 88) or Hancock (n = 41) prostheses between 1975 and 1993 were reviewed. The operation required a repeat median sternotomy in 66 of 129 (51%) patients, whereas 67 of 129 (52%) underwent double or triple valve replacement. Operative mortality was 14% (2/14) in patients undergoing first-time isolated tricuspid valve replacement and 27% (35/129) overall. Survival at 5, 10, and 14 years was 56% +/- 5%, 48% +/- 5%, and 31% +/- 9%, and freedom from tricuspid reoperation at 5, 10, and 14 years was 96% +/- 3%, 93% +/- 4%, and 49% +/- 17%. No valve thrombosis was observed. In this largest reported series of porcine bioprostheses in the tricuspid position, long-term freedom from valve-related events was excellent because of a low incidence of valve thrombosis and a valve durability of 13 to 15 years in a population with limited life expectancy.

Bioprosthesis↗
PubMed1995

A comparison of amrinone with sodium nitroprusside for control of hemodynamics during infrarenal abdominal aortic surgery.

OBJECTIVES: The control of hemodynamic changes during surgical resection of abdominal aortic aneurysms (AAA) remains a challenge to anesthesiologists. In the past, hypertensive episodes have been treated with sodium nitroprusside (SNP). However, amrinone may provide some benefits when compared with SNP because of its positive inotropic and vasodilatory properties. Therefore, the purpose of this study was to compare amrinone with SNP for hemodynamic control during AAA surgery. DESIGN: This study was a prospective, randomized investigation. SETTING: This study was performed at a single university hospital. PARTICIPANTS: This study included 20 patients undergoing AAA resection. INTERVENTIONS: After institutional review board approval, participants were randomized to receive either SNP (group N = 10) or amrinone (group A = 10). Both agents were started 10 minutes before aortic cross-clamping and discontinued 10 minutes before unclamping. Anesthesia was induced with thiopental or etomidate and maintained with oxygen, nitrous oxide, isoflurane, fentanyl, and vecuronium. Hemodynamic measurements included heart rate, systolic and diastolic blood pressure, cardiac output, systolic and diastolic pulmonary artery pressure, pulmonary capillary wedge pressure, central venous pressure, mixed venous oxygen saturation, electrocardiogram, and ST-T wave trend analysis. MEASUREMENTS AND MAIN RESULTS: Demographic and clinical characteristics for the two groups were similar. Mixed venous oxygen saturation was significantly lower (p < 0.05) in group N immediately after unclamping. There were no differences between groups for the other measurements studied. There were no episodes of myocardial ischemia in either group. CONCLUSIONS: This study demonstrates that amrinone provides equivalent hemodynamic control to SNP during abdominal aortic aneurysm surgery because it allows moderate reductions in blood pressure without affecting other hemodynamic measurements. Further studies are needed to assess whether patients with poor preoperative left ventricular function would benefit from amrinone management during AAA resection.

Aged↗
PubMed1995

Aging increases pharmacodynamic sensitivity to the hypnotic effects of midazolam.

The effect of aging on the pharmacodynamics of midazolam was investigated in a double-blinded study involving 39 consenting patients ranging in age from 39 to 77 yr. Midazolam was infused intravenously (i.v.) using a pharmacokinetic model-driven drug infusion device to achieve a plasma midazolam concentration that was held constant for the 10-min duration of the study. Blood samples were obtained from the radial artery at 5 and 10 min for subsequent measurement of the plasma midazolam concentrations. With the 10-min sample, the patients were also assessed for the presence or absence of responsiveness to verbal command. To ensure that the pharmacodynamic end-point was assessed under the condition of a relative steady-state effect-site midazolam concentration, only those patients (n = 33) in whom the plasma midazolam concentration at 10 min was within 30% of the measured concentration at 5 min were included in the subsequent data analyses. Logistic regression was used to fit the verbal command response/no response data to a mathematical model that included patient age and the plasma midazolam concentration measured at 10 min. Cp50, the steady-state plasma midazolam concentration at which 50% of patients would be expected not to respond to a specific stimulus (e.g., verbal command), was calculated as a function of age from the parameterized logistic model. The midazolam Cp50 for response to verbal command decreased significantly (P = 0.034) with increasing patient age, demonstrating that aging increases pharmacodynamic sensitivity to the hypnotic effects of midazolam independent of pharmacokinetic factors.

Adult↗
PubMed1995

Differential age effects of mean arterial pressure and rewarming on cognitive dysfunction after cardiac surgery.

Central nervous system dysfunction is a common consequence of otherwise uncomplicated cardiac surgery. Many mechanisms have been postulated for the cognitive dysfunction that is part of these neurologic sequelae. The purpose of our investigation was to evaluate the effects of mean arterial pressure (MAP) during cardiopulmonary bypass (CPB) and the rate of rewarming on cognitive decline after cardiac surgery. Two hundred thirty-seven patients completed preoperative and predischarge neuropsychologic testing. MAP and temperature were recorded at 1-min intervals using an automated anesthesia record keeper. MAP area less than 50 mm Hg (time and degree of hypotension), as well as the maximal rewarming rate, were determined for each patient. Multivariable linear regression revealed that the rate of rewarming and MAP were unrelated to cognitive decline. However, interactions significantly associated with cognitive decline were found between age and MAP area less than 50 mm Hg on one measure, and between age and rewarming rate in another, identifying susceptibility of the elderly to these factors. Although MAP and rewarming were not the primary determinates of cognitive decline in this surgical population, hypotension and rapid rewarming contributed significantly to cognitive dysfunction in the elderly.

Aged↗
PubMed1995

Are modern imaging techniques over diagnosing ureteropelvic junction obstruction?

Since the widespread use of real-time ultrasonography in the early 1980s, ureteropelvic junction obstruction has been diagnosed at earlier ages and prenatally on a presumptive basis. However, substantial controversy exists over the diagnosis and treatment of ureteropelvic junction obstruction. We conducted an epidemiological study to determine if modern imaging techniques are leading to the over diagnosis of ureteropelvic junction obstruction. Records were collected retrospectively from 3 hospitals serving 2 adjacent counties to determine the number of pyeloplasties performed in 1970 to 1992. The 2 university hospitals and 1 large private hospital provide a wide variety of services and choice of urologists, and so it was assumed that most patients requiring pyeloplasty in the area would be captured. Of the 555 pyeloplasties 240 (43%) were performed on children 12 years old or younger. Logistic regression analysis revealed an overall increase of pyeloplasties per year of 56.8% in 23 years, which was not markedly different from the population growth in the area in the same period (49.3%). A statistically significant increase in the number of pyeloplasties performed in the first year of life was noted. This trend appeared to begin in 1981: 8 pyeloplasties were performed in the first year of life between 1970 and 1980 compared to 91 between 1981 and 1992. Pyeloplasties in children 1 to 6 years old increased with time at a much lower rate that was not statistically significant and the number of pyeloplasties decreased in those 7 to 12 years old. Therefore, it appears that modern imaging techniques are not leading to an over diagnosis of ureteropelvic junction obstruction but to detection of the disease at an earlier age.

Adolescent↗