Search PubMed⌕ Search

Biomedical subjects

K R Smith

Publications and source records attributed to K R Smith.

At least 73 records · Page 4Linked to original sources
PubMed1997

Mobilization of iron from urban particulates leads to generation of reactive oxygen species in vitro and induction of ferritin synthesis in human lung epithelial cells.

Many of the biochemical effects of asbestos in cultured cells have been shown to be due to iron, which can be as high as 27% by weight. Urban air particulates also contain iron, and some of the pathological effects after inhalation may be due to reactive oxygen species produced by iron-catalyzed reactions. Two standard reference material (SRM) urban air particulate samples were used for the studies described here. SRM 1648 (3.9% iron by weight) was collected in the St. Louis, MO, area, and SRM 1649 (3% iron by weight) was collected in the Washington, DC, area. To determine if iron associated with urban particulates could be mobilized, as it is from asbestos, SRMs 1648 and 1649 were incubated with 1 mM citrate or EDTA, in the presence or absence of ascorbate. Iron was mobilized from both particulates by either chelator, especially in the presence of ascorbate. Citrate, in the presence of ascorbate, mobilized 30.9 nmol of Fe/mg of SRM 1648 and 65.1 nmol of Fe/mg of SRM 1649 in 24 h. EDTA, in the presence of ascorbate, mobilized 53.8 nmol of Fe/mg of SRM 1648 and 98.8 nmol of Fe/mg of SRM 1649 in 24 h. To determine whether reactive oxygen species were being produced by the particulate iron, each particulate was incubated with phi X174 RFI DNA in the presence or absence of ascorbate. Single-strand breaks (SSBs) were produced by either particulate, but only in the presence of ascorbate. Incubation of SRM 1648 or 1649 (0.5 mg/mL) with DNA in the presence of ascorbate and citrate resulted in 20% or 34% DNA with SSBs, respectively. Incubation of SRM 1648 or 1649 (0.1 mg/mL) with DNA in the presence of ascorbate and EDTA resulted in 26% or 45% DNA with SSBs, respectively. To determine if iron associated with urban particulates could be mobilized by human lung epithelial cells (A549), cells were treated with particulates and the amount of the iron storage protein ferritin was determined at the end of treatment. The 6.4- or 8.4-fold increase in ferritin observed in cells treated with SRM 1648 or 1649, respectively, over that of control (untreated) cells strongly suggested that iron was mobilized in the cultured cells. If similar mobilization and reactivity of the iron occurs in the lung, this may explain some of the pathological effects of urban particulates.

Air Pollutants↗
PubMed1997

Psychological responses to BRCA1 mutation testing: preliminary findings.

The short-term psychological responses of 60 adult women tested for a BRCA1 gene mutation associated with a high risk of breast and ovarian cancer were investigated. Participants were members of a large kindred enrolled in an ongoing prospective study of the psychosocial impact of genetic testing. Initial results from participants who completed both the pretest baseline and the 1-2 week posttest follow-up interviews are reported. Gene mutation carriers manifested significantly higher levels of test-related psychological distress, as measured by the Impact of Event Scale, when compared with noncarriers. The highest levels of test-related distress were observed among mutation carriers with no history of cancer or cancer-related surgery. Although general distress (state anxiety) declined after testing, carriers were more distressed than noncarriers at follow-up.

Adolescent↗
PubMed1997

Diagnosis of Neisseria gonorrhoeae infections in women by using the ligase chain reaction on patient-obtained vaginal swabs.

The increased sensitivities of nucleic acid amplification tests such as ligase chain reaction (LCR) have the potential to simplify specimen collection for gonorrhea diagnosis. In this study patients took their own vaginal swab specimens for gonorrhea culture and LCR testing. Immediately following specimen collection by patients, a trained clinician obtained endocervical swab specimens for the same tests. By using LCR to diagnose gonorrhea, 54 (17.5%) of 309 patients had positive tests. Forty-five patients with positive cervical LCR tests also had positive vaginal LCR tests; for one patient, only a cervical LCR specimen was positive, and for eight patients, only vaginal specimens were positive. For specimens from patients whose gonorrhea cultures were positive, all vaginal swab specimens were positive by LCR and 42 (91%) of 46 cervical swab specimens were positive by LCR. LCR-positive specimens from eight patients with negative cultures (four with positive vaginal specimens only, one with a positive cervical specimen only, and three with positive vaginal and cervical specimens) were further evaluated with unrelated probe sets for gonococcal pilin B. Following resolution of the discrepancies between culture-negative and LCR-positive specimens, a diagnosis of gonorrhea could be confirmed for 52 of 54 patients with positive LCR tests. LCR testing with vaginal swabs was 100% sensitive and 99.6% specific and had a positive predictive value of 98.1% and a negative predictive value of 100%. In this study LCR testing of vaginal swab specimens obtained by patients themselves was significantly more sensitive for gonorrhea diagnosis of women than cervical LCR or culture (100% versus 84.6% for cervical LCR or culture; Mantel-Haenszel chi-square test result, 8.58; P = 0.003).

Adolescent↗
PubMed1997

Chart recorder paper minder.

Many paper based chart recorders still suffer from paper uptake systems for the collection of chart record that operate inefficiently or haphazardly. An efficient low cost paper minder using 1.2 mm diameter stainless steel wire for the Siemens-Elema AB Mingograph 7, has been developed. This wire pivots from the end of the chart viewing table and provides an effective force to redirect paper into the standard collecting basket over the entire range of paper speeds.

Medical Records↗
PubMed1996

Large-dose intrathecal morphine for coronary artery bypass grafting.

Aggressive control of pain during the immediate postoperative period after cardiac surgery, associated with decreased blood catecholamine levels, may decrease morbidity and mortality. This study investigated the use of large-dose intrathecal morphine for cardiac surgery and its effect on postoperative analgesic requirements and blood catecholamine levels. Patients were randomized to receive either 4.0 mg of intrathecal morphine (Group MS) or intrathecal saline placebo (Group NS). Perioperative care was standardized and included postoperative patient-controlled analgesia. Arterial blood samples were obtained perioperatively to ascertain catecholamine levels. Patients in Group MS required significantly less postoperative intravenous morphine than patients in Group NS. Although perioperative norepinephrine and epinephrine levels in Group MS patients tended to be lower than Group NS patients, the differences were not statistically significant. In conclusion, large-dose intrathecal morphine initiates reliable postoperative analgesia but does not reliably attenuate the stress response during and after cardiac surgery.

Adult↗
PubMed1996

Association of physical and behavioral characteristics with menstrual cycle patterns in women age 29-31 years.

We examined the association between menstrual cycle characteristics (cycle length, variability, and bleeding length) and physical and behavioral attributes in 766 women age 29-31 years. Menstrual cycle data were prospectively recorded as part of the Menstruation and Reproductive History Study of college women in Minnesota, begun by Alan Treloar in 1934. Data on lifetime height, weight, physical activity, alcohol and caffeine consumption, and smoking history were collected in 1990 using a self-administered questionnaire. Cycle variability, as measured by the standard deviation of the cycle length, was increased, and menstrual cycles > or = 42 days in length were more common among women in the lowest quartile of Quetelet index [odds ratio (OR) for long cycle = 1.6;95% confidence interval (CI) = 0.82-3.0] and among the most physically active (OR = 1.7;95% CI = 0.93-3.1). Long menstrual cycles were less common (OR = 0.40;95% CI = 0.22-0.73) among women who drank alcohol than among nondrinkers. Variable or long menstrual cycles may reflect anovulation and relatively low levels of estrogen exposure. We would expect, based on our data, reduced estrogen exposure among lean women, physically active women, and those who do not consume alcohol. These findings suggest an explanation for the reported associations between these factors and breast cancer risk.

Adult↗
PubMed1996

Comparison of standardized patients and faculty in teaching medical interviewing.

PURPOSE: This randomized controlled study compared the interviewing skills of first-year medical students receiving feedback primarily from standardized patients (SPs) with those of students receiving feedback primarily from faculty. METHOD: All 154 first-year students at the University of Oklahoma College of Medicine in 1993-94 were video-taped to assess baseline and post-instruction interviewing skills. All the students, randomized to one of three study groups, attended two four-hour workshops on interviewing skills. Instruction in the groups was as similar as possible except in the matter of who provided feedback. Two rating systems were used to rate the videotaped interviews for performances of targeted skills. RESULTS: Complete, usable data were available for 120 (78%) of the students. Skill ratings using the Arizona Clinical Interview Rating Scale were significantly higher for the "types of questions used" and "use of empathy" items in the SP-led feedback group. No significant difference in ratings was detected among the groups as measured by the Rotor Interactional Analysis System. CONCLUSION: The SPs were at least as effective as the faculty in effecting behavioral changes in the first-year medical students' interviewing skills.

Education, Medical, Undergraduate↗
PubMed1996

Prevalence of fluorescent monoclonal antibody-nonreactive Neisseria gonorrhoeae in five North American sexually transmitted disease clinics.

We compared a direct fluorescent monoclonal antibody (DFA) test with alternative enzymatic and fermentation tests for identifying presumptive gonococcal isolates in a systematic sample from patients attending five sexually transmitted disease clinics in five cities. Fourteen (2.5%) of 556 isolates from three clinics were nonreactive with DFA confirmatory reagent and reactive by both the Quad-Ferm (BioMerieux Vitek Inc.) and the Rapid NH (Innovative Diagnostic Systems, Inc.) tests. The prevalence of DFA-nonreactive Neisseria gonorrhoeae isolates varies geographically and is independent of local methods for the identification of possible gonococci.

Ambulatory Care Facilities↗
PubMed1995

Breast cancer mortality among immigrants in Australia and Canada.

BACKGROUND: By moving between geographic regions with differing levels of breast cancer risk, migrant populations of women provide a unique opportunity to examine the impact of exposure to new environments and lifestyles on breast cancer risk. Breast cancer incidence and mortality rates for the majority of migrant groups originating from countries with low breast cancer risk have been found to increase toward the rates observed in destination countries with populations at higher risk for this disease. Because very little information exists on migrants from high- to low-risk countries, it is not known whether rates for these groups decrease or whether migrant groups generally experience increases in breast cancer rates. PURPOSE: To address these questions, we determined the breast cancer mortality rates for women from both lower and higher risk countries who had immigrated to Australia and Canada and compared these rates with those exhibited by the population in the origin country and by the destination native-born population. METHODS: Individual mortality records covering the years 1984 through 1988 and 1986 census data for Australia and Canada were obtained. Direct age-standardized mortality rates and rate ratios (and their 95% confidence intervals) were calculated for immigrant groups in Australia and Canada. Age-standardized rate ratios by length of residence in Australia were calculated. Weighted regression analyses of observed and expected mortality changes were performed. RESULTS: In Australia, the mortality rates for 12 (75%) of 16 immigrant groups from lower risk countries and 10 (71.4%) of 14 groups from higher risk countries shifted toward the rate of native-born Australians. In Canada, the rates for 12 (60%) of 20 immigrant groups from lower risk countries and four (80%) of five groups from higher risk countries converged to the rate of native-born Canadians. Overall, the extent of convergence (shift of immigrant's mortality rate in origin country toward rate of native-born population) was 50% for immigrants in Australia and 38% for immigrants in Canada. Although there was not a consistent pattern of convergence with length of residence in Australia, after 30 or more years, the mortality rates of 15 (83.3%) of 18 immigrant groups had shifted toward the rate of the native-born Australians. Because of the small number of deaths in many of the immigrant groups studied, the observed differences in the breast cancer mortality age-standardized rates between the origin country and immigrant group, although often substantial, were seldom statistically significant. CONCLUSIONS: Breast cancer mortality rates among women in the majority of immigrant groups shifted from the rate observed in their country of origin toward the rate of the native-born population in the destination country. IMPLICATIONS: These findings indicate that environmental and lifestyle factors associated with the new place of residence influence the breast cancer rates of immigrants and also suggest that, since most migrants migrate as adults, the risk of breast cancer can be altered in later life.

Adult↗
PubMed1995

Estimating standardized mortality odds ratios with national mortality followback data.

Proportionate mortality analyses are often used to study cause-specific mortality when population denominators are not available. The purpose of this paper is to present an extension of published proportionate mortality ratio logistic regression methods used to analyze such data. This paper describes methods used to estimate standardized mortality odds ratios (SMORs) with numerator data and the problems encountered when external standard rates are not available for all strata of interest. This paper focuses on the case where one has representative mortality followback data. These data are based on a large, representative sample of deaths from a defined population for whom numerous covariates about the decedents are collected from surviving family members. With these data, one may use logistic regression methods to generate fully standardized estimates of risk, SMORs, with numerator data. It is also possible to generate SMORs that allow for effect modification. Mortality followback data are also a more flexible data source from which one may generate substitutes for external standard mortality rate ratios to be used with previously developed SMOR methods. An application of the methods is provided using logistic regression.

Heart Diseases↗
PubMed1995

Portosystemic communications: follow-up of 32 cases.

A multicentre retrospective study of dogs that underwent surgical attenuation of portosystemic communications (PSC) was conducted. These dogs were followed from three months after surgery to evaluate the long term effect of surgery on their life span, disease-free interval, and owner assessment of postoperative quality of life of the dogs. Seventy-five per cent of the dogs in this study had no long term postoperative recurrence of clinical signs. Of the 25 per cent of dogs that showed recurrent clinical signs, all but one had partial attenuation of the PSC. The location of the PSC was the only factor that correlated with whether the dogs were still alive. All owners were pleased with the postoperative quality of life of their dogs.

Analysis of Variance↗
PubMed1995

Evaluation of ligase chain reaction for use with urine for identification of Neisseria gonorrhoeae in females attending a sexually transmitted disease clinic.

The high sensitivity of nucleic acid amplification tests such as ligase chain reaction (LCR) has the potential to simplify specimen collection for the microbiologic diagnosis of gonorrhea. We screened first-void urine specimens from 283 women attending a Birmingham, Ala., sexually transmitted disease (STD) clinic by using LCR and compared the results to those of cervical and urethral cultures for gonorrhea diagnosis. Fifty-three (18.7%) women had positive cervical cultures for gonorrhea, and 41 of the 53 (77%) also had positive urethral cultures. One additional patient had only a positive urethral culture (the cervical gonorrhea culture was negative). LCR testing of urine specimens for gonorrhea yielded positive results for 51 of 54 (94.4%) women with positive cervical or urethral cultures. Of 229 women with both urethral and cervical cultures negative for gonorrhea, 2 (0.8%) had positive urine LCR results as well. To resolve the discrepancies between urine LCR and culture results, LCR tests of simultaneously collected urethral and cervical swab specimens and LCR tests of the same urine specimens using different nucleotide primers were conducted. After evaluation of five discrepant results, the sensitivity, specificity, positive predictive value, and negative predictive value of LCR for the detection of gonorrhea in urine specimens were 94.6%, 100%, 100%, and 98.7%, respectively. We conclude that urine LCR testing for Neisseria gonorrhoeae is a practical alternative to culture for the detection of gonorrhea in women. Urine testing for STD diagnosis has the potential to simplify and expand the opportunities for STD screening and surveillance of women.

Ambulatory Care Facilities↗
PubMed1995

Attitudes toward genetic testing for colon cancer risk.

This study examined public interest regarding genetic testing for colon cancer susceptibility. Survey data were collected from 383 adults in Utah. Respondents were very (47.3%) or somewhat (36.6%) interested in taking this genetic test. Nearly 95% reported that they would share their results with others. Individuals with higher income and with a perceived risk of getting colon cancer were the most interested in testing. Individuals without health insurance and widowed individuals were the least likely to share their test results. If respondents were told that they carried a gene for colon cancer, most would be concerned with how to reduce their risk of getting the disease.

Adult↗
PubMed1995

Clinical applications of frameless stereotactic devices in neurotology: preliminary report.

Conventional stereotactic surgery has been utilized primarily for intracranial neuro-surgical procedures. Despite their utility, head-frame systems are restrictive and often inconvenient, thus they have not proved applicable for neurotologic surgery. Recently frameless stereotactic navigational systems have been developed that employ three-dimensional digitizers to transform the coordinates in surgical space to the corresponding image space, without the employment of head frames. This allows the determination of position of a surgical instrument in real time during surgery, and its display on video-projected computed tomography or magnetic resonance imaging scanned images. This preliminary report focuses upon an optoelectric referenced frameless stereo-tactic system, the NeuroStation, as it relates to minimally invasive neurotologic surgery. Clinical applications, limitations, and future directions are discussed, and three representative surgical cases are presented. This device has potential as an adjunctive navigational tool for certain neurotologic procedures.

Adult↗
PubMed1994

Menstrual cycle patterns and risk of breast cancer.

Menstrual cycle characteristics may reflect underlying endocrine patterns that influence the risk of breast cancer. Most previous studies of menstrual function and breast cancer risk have used retrospective reports of menstrual bleeding, which may be unreliable. To examine this association, the authors conducted a mail survey among 997 women who had recorded menstrual events prospectively over as many as 50 years, beginning in 1934. Compared with women with a median menstrual cycle length of 26-29 days, women who had cycles of extreme length at ages 25-29 years had a nearly twofold increased incidence of breast cancer (for a median cycle length of less than 26 days, adjusted relative risk (RR) = 1.9, 95% CI 0.9-4.1; for > or = 34 days, RR = 1.9, 95% CI 0.9-3.9). Statistical adjustment was made for age, family history of breast cancer, parity, age at menopause, age at first pregnancy, and Quetelet index (weight (kg)/height (m)2). Adjusting for age and other potential confounders and restricting the analysis to women who did not use hormones, women who experienced either a lesser (< 150) or a greater (> 350) cumulative number of cycles had an increased incidence of breast cancer (adjusted RR = 1.9, 95% CI 0.3-10.6, and RR = 1.8, 95% CI 0.5-6.0, respectively) compared with women who experienced 150-350 cycles. The findings are discussed in the context of current hormonal theories of breast cancer etiology.

Adult↗
PubMed1994

Neurobehavioral effects of phenytoin and carbamazepine in patients recovering from brain trauma: a comparative study.

OBJECTIVE: To compare the effects of prophylactic anticonvulsant use of phenytoin and carbamazepine on the cognitive and emotional status of the patient after brain injury. DESIGN: Double-blind, placebo-controlled study with assessments before and after withdrawal from drug treatment. SETTING: Patients had been initially treated by neurosurgeons at a university hospital and were followed up during the study on an outpatient basis. PATIENTS: Forty of 64 patients receiving phenytoin and 42 of 127 patients receiving carbamazepine from 6 to 44 months for seizure prophylaxis after brain injury met study criteria and were assigned to continue or discontinue treatment. Groups were balanced for age, sex, race, weight, intelligence, type of injury, duration of therapy, and drug plasma concentration at screening. INTERVENTION: A battery of neuropsychological tests was administered twice during a 4-week baseline period, at the end of a 4- to 5-week period of continued drug treatment or placebo, and after 4 weeks of not receiving medication. MAIN OUTCOME MEASURES: Attention and concentration, psychomotor speed, memory, verbal fluency, and emotional state. RESULTS: No significant differences were found in the performance of patients in medication and placebo groups for either drug at the end of the placebo phase. Patients in the combined groups showed significant improvement (P < .01) on several measures of motor and speeded performance following cessation of drug treatment. Multivariate analyses showed additional differences between phenytoin and carbamazepine and also suggested a significant practice effect on some measures used. CONCLUSIONS: Both phenytoin and carbamazepine seem to have negative effects on cognitive performance, particularly on tasks with significant motor and speed components. Practice effects were noted and may account for much of the improvement when patients stopped taking the drugs. Overall effects of the drugs were small and of limited clinical significance, but differences among subjects were noted that may affect selection of a particular drug for the individual patient.

Adult↗