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Biomedical subjects

S Swan

Publications and source records attributed to S Swan.

At least 19 recordsLinked to original sources
PubMed2005

Posaconazole pharmacokinetics, safety, and tolerability in subjects with varying degrees of chronic renal disease.

Posaconazole is a triazole antifungal in development for the treatment of invasive fungal infections. The authors evaluated the pharmacokinetics and safety of posaconazole in healthy subjects and in those with mild (CL(CR) = 50-80 mL/min), moderate (CL(CR) = 20-49 mL/min), and severe chronic renal disease (CL(CR) <20 mL/min; receiving outpatient hemodialysis) (n = 6/group). Subjects received one 400-mg dose of posaconazole oral suspension with a standardized high-fat breakfast. For hemodialysis-dependent subjects, this dose was given on a nonhemodialysis day, and a second 400-mg dose was given 6 hours before hemodialysis. Blood samples were collected before dose and up to 120 hours postdose. For hemodialysis-dependent subjects following the second dose, additional samples (predialyzed and postdialyzed) were collected before, during, and after dialysis. There was no correlation between posaconazole pharmacokinetics and mild to moderate renal disease; the slopes of the linear regressions for creatinine clearance versus posaconazole AUC, C(max), CL/F, and t1/2 values were not significantly different from zero (P > .130). Mean CL/F values before and during hemodialysis were comparable. Furthermore, the difference in the predialyzed and postdialyzed posaconazole concentrations was only approximately 3%, supporting that posaconazole was not removed by hemodialysis. Protein binding was similar in all groups (approximately 98%) and was unaffected by hemodialysis. Posaconazole was generally well tolerated. One patient had elevated liver function test results that were not present at baseline and were thought to be possibly related to posaconazole. Results of this single-dose study indicate that dosage adjustments for patients with varying degrees of renal disease are not required.

Administration, Oral↗
PubMed2000

Prevalence of family violence in clients entering substance abuse treatment.

The present study evaluated 105 clients who were assessed for substance-related problems and a history of domestic violence. A brief survey on family violence examined whether clients were adult victims, childhood victims, and/or perpetrators of physical violence. Results indicated that 37% of the sample reported that they experienced a family history of physical violence. A total of 22% reported being an adult victim of physical violence, 14% reported being a victim of childhood abuse, and 18% reported being a perpetrator of physical violence. There was a significant positive correlation between subtypes of family violence. Substance-using clients who were older reported more incidences of family violence. Results showed that substance-using clients with a history of family violence (SAFV+) tended to have more individual therapy sessions attended than substance-using clients without a history of family violence (SAFV-). The SAFV+ group was different from the SAFV- group in that they had significantly higher scores on the Michigan Alcoholism Screening Test and the Beck Depression Inventory (BDI) scores. The SAFV+ group also had significantly more self-reported and positive urine screens for cocaine use within the 2-month monitoring period. Additionally, substance-using clients with a history of childhood trauma had significantly more individual therapy sessions attended than clients without a history of childhood trauma. The group with a history of childhood trauma had significantly higher scores on the BDI. Findings indicate the importance of assessing family history of violence in substance abusers entering treatment, as this may have significant implications for treatment outcome.

Adult↗
PubMed2000

Motivation to change substance use among offenders of domestic violence.

Substance use alone leads to increased rates of violence, reduction in adherence to treatment regimes, and other negative psychiatric sequelae. Given the high rates of co-occurring substance use and family violence-related problems, substance use was assessed among offenders of domestic violence who were mandated by court to attend anger management classes. Rates of substance dependence diagnoses ranged from 33 to 50%, while rates of substance abuse diagnoses ranged from 60 to 75%. This study evaluated the effectiveness of a motivational enhancement intervention on readiness to change substance use. Two anger management groups were targeted to assess substance use, violence, and motivation to change substance use behaviors. One group was randomly chosen to partake in a motivational enhancement intervention session. The comparison group was offered standard anger management classes. Forty-one clients were evaluated for substance abuse and dependence diagnosis using criteria from the Diagnostic and Statistical Manual of Mental Disorders, 4th ed. A brief motivation to change survey, adapted from the Readiness to Change subscale of the Stages of Change Readiness and Treatment Eagerness Scale was administered pre- and postsession. Results indicate that a motivational enhancement intervention is feasible and effective in increasing readiness to change substance use among domestic violence offenders. The results illustrate the importance of assessing and treating substance use among offenders of domestic violence, as this may be an important indicator for higher dropout rates and reoffenses among this population.

Adult↗
PubMed2000

The pharmacokinetics of ziprasidone in subjects with normal and impaired renal function.

AIMS: To assess whether renal impairment influences the pharmacokinetics of ziprasidone, and to determine whether ziprasidone is cleared via haemodialysis. METHODS: Thirty-nine subjects with varying degrees of renal impairment were enrolled into an open-label, multicentre, multiple-dose study and assigned to four groups according to their renal function: normal (group 1, creatinine clearance > 70 ml min(-1); mildly impaired (group 2, creatinine clearance 30-60 ml min(-1); moderately impaired (group 3, creatinine clearance 10-29 ml min(-1), and severely impaired (group 4, requiring haemodialysis three times-a-week). Subjects received ziprasidone 40 mg day(-1), given orally with food, as two divided daily doses for 7 days and a single 20 mg dose on the morning of day 8. Pharmacokinetic variables were determined from multiple venous blood samples collected on days 1 and 8 (haemodialysis day for subjects with severe renal impairment). Additional samples were collected from subjects with severe renal impairment on day 7 (nonhaemodialysis day). RESULTS: On day 1 there were no statistically significant differences in the pharmacokinetics (AUC(0, 12 h), Cmax, tmax) of ziprasidone among subjects with normal renal function and those with mild, moderate and severe renal impairment. The AUC(0,12 h) and Cmax in subjects with mildly impaired renal function were statistically significantly greater than in those with moderately impaired renal function (P = 0.0163-0.0385). The mean AUC(0,12 h) was 272, 370, 250 and 297 ng ml(-1) h in groups 1, 2, 3 and 4, respectively. Corresponding mean Cmax values were 47, 61, 41 and 50 ng ml(-1) and corresponding mean tmax values were 5, 6, 5 and 5 h. On day 8 there were no statistically significant differences in the pharmacokinetics (AUC(0,12 h), Cmax, tmax, lambda(z), Fb) of ziprasidone among subjects with normal renal function and those with moderate or severe renal impairment. The AUC(0,12 h) in subjects with mild renal impairment was statistically significantly greater than those in the other three groups (P = 0.0025-0.0221), but this was not considered clinically significant. The mean AUC(0,12 h) were 446, 650, 389 and 427 ng ml(-1) h in groups 1, 2, 3 and 4, respectively. Corresponding mean Cmax values were 68, 93, 54 and 70 ng ml(-1), corresponding mean tmax values were 4, 5, 4 and 5 h and corresponding mean lambda(z) were 0.14, 0.11, 0.14 and 0.17 h(-1). The mean percentage Fb was 99.84-99.88% across all groups and the mean t(1/2),z ranged from 4.2 to 6.4 h. Comparison of the mean AUC(0,12 h) and Cmax values in subjects with severe renal impairment on day 7 with those on day 8 suggested that haemodialysis does not have a clinically significant effect on the pharmacokinetics of ziprasidone. CONCLUSIONS: The findings of this study indicate that mild-to-moderate impairment of renal function does not result in clinically significant alteration of ziprasidone pharmacokinetics and therefore does not necessitate dose adjustment.

Adolescent↗
PubMed1999

Psychological stress in the workplace and menstrual function.

The relation between psychological stress at work and menstrual function was examined for 276 healthy, working, premenopausal women who participated in the California Women's Reproductive Health Study in 1990-1991. Subjects collected daily urine samples and completed a daily diary for an average of five menstrual cycles. Metabolites of estrogen and progesterone were measured in the urine, and computer algorithms were developed to characterize each cycle as ovulatory or anovulatory and to select a probable day of ovulation. A telephone interview collected information about psychological stress at work as well as other occupational, demographic, lifestyle, and environmental factors. Logistic regression was used to model stressful work and risk of anovulation (> or = 36 days without ovulating) and measures of within-woman cycle variability. Repeated measures analyses were performed on other menstrual cycle parameters. Stressful work (high demand in combination with low control) was not strongly related to an increased risk for anovulation or cycle variability or to any of the following cycle endpoints: short luteal phase (< or = 10 days), long follicular phase (> or = 24 days), long menses (> or = 8 days), or long cycle (> or = 36 days). However, women in stressful jobs had a more than doubled risk for short cycle length (< or = 24 days) compared with women not working in stressful jobs (adjusted odds ratio = 2.24, 95% confidence interval 1.09-4.59).

Adolescent↗
PubMed1999

Sodium ferric gluconate complex in sucrose is safe and effective in hemodialysis patients: North American Clinical Trial.

A new intravenous (i.v.) iron compound, sodium ferric gluconate complex in sucrose (Ferrlecit, R&D Laboratories, Inc, Marina Del Rey, CA), was administered over 8 consecutive dialysis days in equally divided doses to a total of either 0.5 or 1.0 g in a controlled, open, multicenter, randomized clinical study of anemic, iron-deficient hemodialysis patients receiving recombinant human erythropoietin (rHuEPO). Effectiveness was assessed by increase in hemoglobin and hematocrit and changes of iron parameters. Results were compared with historically matched controls on oral iron. High-dose i.v. treatment with 1.0 g sodium ferric gluconate complex in sucrose resulted in significantly greater improvement in hemoglobin, hematocrit, iron saturation, and serum ferritin at all time points, as compared with low-dose i.v. (0.5 g) or oral iron treatment. Despite an initial improvement in mean serum ferritin and transferrin saturation, 500 mg i.v. therapy did not result in a significant improvement in hemoglobin at any time. Eighty-three of 88 patients completed treatment with sodium ferric gluconate complex in sucrose: 44 in the high-dose and 39 in the low-dose group. Two patients discontinued for personal reasons. The other three discontinued because of a rash, nausea and rash, and chest pain with pruritus, respectively. In comparison with 25 matched control patients, adverse events could not be linked to drug therapy, nor was there a dose effect. In conclusion, sodium ferric gluconate complex in sucrose is safe and effective in the management of iron-deficiency anemia in severely iron-deficient and anemic hemodialysis patients receiving rHuEPO. This study confirms the concepts regarding iron therapy expressed in the National Kidney Foundation Dialysis Outcomes Quality Initiative (NKF-DOQI) that hemodialysis patients with serum ferritin below 100 ng/mL or transferrin saturations below 18% need supplementation with parenteral iron in excess of 1.0 g to achieve optimal response in hemoglobin and hematocrit levels.

Adult↗
PubMed1999

New approaches for estimating risk from exposure to diethylstilbestrol.

A subgroup from a National Institute of Environmental Health Sciences, workshop concerned with characterizing the effects of endocrine disruptors on human health at environmental exposure levels considered the question, If diethylstilbestrol (DES) were introduced into the market for human use today and likely to result in low-dose exposure of the human fetus, what would be required to assess risk? On the basis of an analysis of the quality of data on human DES exposure, the critical times and doses for inducing genital tract malformations and cancer must be determined. This would be facilitated through analysis of the ontogeny of estrogen receptor expression in the developing human genital tract. Models of low-dose estrogenic effects will have to be developed for human and rodent genital tract development. Mouse models offer many advantages over other potential animal models because of the wealth of the earlier literature, the availability of sensitive end points, the availability of mutant lines, and the possibility of generating genetically engineered model systems. Through multidisciplinary approaches, it should be possible to elucidate the cellular and molecular mechanisms of endocrine disruption elicited by estrogens during development and facilitate an assessment of risk to humans.

Animals↗
PubMed1998

Green- and red-fluorescent nanospheres for the detection of cell surface receptors by flow cytometry.

Fluorescent probes serve as sensitive tools for obtaining structural and functional information in cellular systems. In spite of the high sensitivity provided by fluorescent reagents, cell surface receptors expressed in low numbers often escape detection with commonly used fluorescent probes. R-Phycoerythrin (R-PE), a molecule with a very high quantum yield, is often the reagent of choice for the detection of such low abundance events. We have developed streptavidin conjugates of two highly fluorescent 35-40 nm diameter polystyrene nanospheres, the green fluorescent FluoSpheres (Ex/Em 505/515) and red fluorescent TransFluoSpheres (Ex/Em 488/645). Like R-PE, the new reagents have peak excitations near 488 nm but differ in their emission maxima; 515 nm for the green nanospheres, 645 nm for the red nanospheres and 575 nm for R-PE. Hence the nanospheres are detected by flow cytometry in channels capable of detecting green (FL1) and red (FL3) fluorescence, while R-PE is detected in channel FL2. These nanospheres were tested for the detection of the sparsely expressed epidermal growth factor receptor (EGFR) of NIH-3T3 cells and the densely expressed EGFR of A431 cells. Results indicate that the nanosphere reagents are more sensitive than fluorescein-streptavidin and at least comparable in sensitivity to R-PE-streptavidin. The simultaneous use of these nanospheres with R-PE was also studied by concurrent staining of the CD3 and CD4 receptors in JURKAT cells. Labeling of CD4 receptors with streptavidin nanospheres and CD3 receptors with the R-PE-anti-CD3 conjugate confirmed the suitability of using the new nanospheres in combination with R-PE in multicolor flow cytometry experiments. This paper thus describes the use of alternative tools with detection sensitivity comparable to that of R-PE, but detected in different channels than R-PE, permitting their simultaneous use with R-PE.

3T3 Cells↗
PubMed1998

A preliminary placebo-controlled crossover trial of fludrocortisone for chronic fatigue syndrome.

OBJECTIVE: To provide a preliminary assessment of the efficacy and safety of fludrocortisone acetate treatment of chronic fatigue syndrome. DESIGN: A placebo-controlled, double-blind, random-allocation crossover trial of 6 weeks of fludrocortisone. SETTING: An outpatient clinical trials unit. PATIENTS: Twenty-five participants with chronic fatigue syndrome (mean age, 40 years; 19 [76%] women; mean duration of illness, 7.0 years) were recruited from a research and clinic registry. Five patients withdrew from the trial. INTERVENTIONS: All participants were scheduled to receive fludrocortisone acetate (0.1-0.2 mg) or a placebo for 6 weeks in each treatment. MAIN OUTCOME MEASURES: Self-administered questionnaires were completed at the beginning and end of each treatment arm that asked patients to rate the severity of their symptoms on a visual analogue scale. The Medical Outcomes Study 36-Item Short-Form Health Survey, a reaction time test, and a treadmill exercise test were used to assess functional status. Blood pressure, heart rate, and plasma norepinephrine levels were obtained at baseline. Blood pressure and heart rate were recorded at the end of the exercise test and monitored at all subsequent visits. RESULTS: At baseline, the study participants reported symptom severity greater than 5 for most symptoms, and all had evidence of marked functional impairments. No improvement was observed in the severity of any symptom or in any test of function for the 20 participants who completed both arms of the trial. Blood pressure and heart rate readings were unaffected by treatment, and plasma norepinephrine levels did not differ from those of a healthy control group. The incidence of adverse experiences was similar in the fludrocortisone and placebo arms of the trial. CONCLUSION: Low-dose fludrocortisone does not provide sufficient benefit to be evident in a preliminary blinded trial of unselected patients with chronic fatigue syndrome.

Adult↗
PubMed1997

Job-related and psychological effects of sexual harassment in the workplace: empirical evidence from two organizations.

Previous evidence regarding the outcomes of sexual harassment in the workplace has come mainly from self-selected samples or analogue studies or those using inadequate measures. The sexual harassment experiences, coping responses, and job-related and psychological outcomes of 447 female private-sector employees and 300 female university employees were examined. Discriminant function analyses indicated that women who had not been harassed and women who had experienced low, moderate, and high frequencies of harassment could be distinguished on the basis of both job-related and psychological outcomes. These outcomes could not be attributed to negative affective disposition, attitudes toward harassment, or general job stress. Results suggest that relatively low-level but frequent types of sexual harassment can have significant negative consequences for working women.

Adult↗
PubMed1995

Silicone breast implants: immunotoxic and epidemiologic issues.

Silicone gel implants for breast augmentation and reconstruction have been in use since 1962. Significant local complications include capsular contracture, rupture, gel "bleed", and spread of the implant material to regional lymph nodes (1-7) as well as histologic findings of foreign body granulomas in the capsular tissue and in lymph nodes (7-9). Through magnetic resonance spectroscopy and atomic emission spectroscopy, silicon compounds were found in the blood of some women with silicone breast implants; silicone and silica have also been found in liver (10). Well-publicized case reports have raised significant concerns regarding an association between implants and systemic disease. However, despite the availability of silicone implants for over 30 years, controlled epidemiological studies were not carried out until 1992. Currently available epidemiologic data are extremely limited. In part, because the majority of implants were used after 1981, the incidence of long-term problems is not yet known. In 1992, due to the unavailability of studies demonstrating the safety of implants, the U.S. Food and Drug Administration advised that silicone breast implants should be used only in reconstructive surgery and as part of clinical trials (11). This decision spurred a wave of research on the bioreactivity of silicone and clinical observations of patients with implants. Herein, we review the adverse immune effects following contact with silicone as well as the epidemiologic data available.

Animals↗
PubMed1994

Person memory and judgment: pragmatic influences on impressions formed in a social context.

Ss who receive information about a person's traits and behaviors in a social context are likely to focus their attention on the pragmatic implications of this information (i.e., why the information was conveyed). To examine this hypothesis, Ss listened to a taped conversation in which a male target (T) and another speaker (O) exchanged anecdotal accounts of T's behavior. Ss typically used O's trait description of T to form an evaluative concept of O rather than of T, whereas T's trait description of himself had no effect on evaluations of him. Ss had better recall of statements O made when they were unfavorable and, therefore, violated a conversational norm to be polite. However, behaviors that T himself mentioned were often recalled better when they were favorable, and therefore, in violation of a normative expectation to appear modest. The inconsistency of T's behaviors with initial trait descriptions of him had little effect on the recall of these behaviors.

Female↗
PubMed1994

Making the system work. Training pediatric oncology patients to cope and their parents to coach them during BMA/LP procedures.

Three 4- to 7-year-old pediatric oncology patients were taught to engage in distraction prior to painful bone marrow aspirations and lumbar puncture procedures and to use party blowers as a breathing technique during the painful procedures. Parents were taught to coach their children to use these coping behaviors. Using a multiple baseline across subjects design, results indicated that all of the parents increased their rate of coaching. Each child responded with increased coping and decreased observable distress after the first treatment session. One child returned to baseline levels of coping and distress on the next two sessions. The other two children maintained their high rates of coping and low rates of observable distress during the remaining treatment and during the maintenance sessions. Parents' coaching of their children to use coping behaviors also remained high during maintenance sessions.

Adaptation, Psychological↗
PubMed1992

Clusters galore: insights about environmental clusters from probability theory.

The posterior probability of a causal explanation given that an environmental cancer cluster is statistically significant depends on the prior probability of an environmentally caused cluster, the sensitivity of the statistical test and its specificity. The prior probability is low, because it is rare to have enough carcinogen in the general environment to cause a relative risk of cancer high enough to achieve statistical significance in a small geographic area. The sensitivity and specificity are not great. The likelihood that a census tract escapes statistically significant elevations in all 80 types of cancer can be calculated. Many of the thousands of census tracts will, by chance alone, have at least one type of cancer whose elevation is statistically significant. Actual observation from a large cancer registry confirms this probabilistic prediction. Applying the principles of Bayes' Theorem would suggest that most statistically significant environmental cancer clusters are not due to environmental carcinogens. One would have to investigate hundreds of environmental cancer clusters to find one with a true environmental cause.

Bayes Theorem↗
PubMed1992

Cyst decompression surgery for autosomal dominant polycystic kidney disease.

A prospective study was undertaken to evaluate the efficacy of surgical cyst decompression for retarding the progression of renal failure and for the management of chronic pain associated with autosomal dominant polycystic kidney disease (ADPKD). Thirty patients with ADPKD and pain (14 patients), renal insufficiency (4 patients), or both (12 patients) underwent unilateral (19 patients) or bilateral (11 patients) cyst reduction surgery. The patients were monitored for 21 +/- 2 months postoperatively. The probability of being painfree was 80% at 1 yr and 62% at 2 yr. Preoperative and 1-to 3-month postoperative serum creatinine levels and GFR (clearance of insulin or (125I) iothalamate) were not significantly different (2.2 +/- 0.3 versus 2.2 +/- 0.3 mg/dL and 49 +/- 8 versus 54 +/- 9 mL/min/1.73 m2, respectively). One-year serum creatinine levels remained unchanged in patients with normal preoperative renal function (1.0 +/- 0.07 versus 1.0 +/- 0.05 mg/dL), whereas those with preoperative progressive renal insufficiency had no difference in the mean slope of reciprocal serum creatinine plots preceding and after surgery (-0.008 +/- 0.001 versus -0.009 +/- 0.002 dL/mg/month). In patients who underwent unilateral surgery, split function isotope scans showed no change in function of the operated kidney when compared with the nonoperated kidney. Surgical cyst decompression provides effective relief of chronic pain without compromising renal function. However, the data in this article do not support the use of this procedure to slow progression of renal insufficiency in ADPKD.

Adult↗
PubMed1992

Cyst fluid from human autosomal dominant polycystic kidneys promotes cyst formation and expansion by renal epithelial cells in vitro.

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by progressive renal enlargement, culminating in renal insufficiency in over one half of affected individuals. The highly variable onset and clinical course of ADPKD may be due to factors extrinsic to the genetically defined renal cysts. In this study, cyst fluid samples from 12 nonazotemic and 18 azotemic ADPKD subjects were examined for in vitro biologic activity that promotes cellular proliferation and the secretion of fluid by renal epithelial monolayers, two pathogenetic mechanisms that have critical roles in the formation and the rate of expansion of renal cysts. Cyst fluid added to culture medium (final concentrations, 1 to 20%) caused Madin-Darby canine kidney cells and human kidney cortex (HKC) cells derived from primary cultures to form cysts in Type I collagen matrix. Cyst fluid stimulated the net transepithelial secretion of fluid by polarized monolayers composed of these same cells. Absolute levels of fluid secretory activity determined by MDCK bioassay were correlated directly with the rate of fluid secretion by HKC cell monolayers and with the extent of cyst formation by MDCK and HKC cells embedded in collagen matrix. The secretory activity of urine was negligible; secretory activity was detectable in the serum of normal and ADPKD subjects, but the levels were much lower than in cyst fluid. cAMP agonists prostaglandins E1 and E2, arginine vasopressin, and 8-Br-cAMP stimulated fluid secretion by MDCK and HKC monolayers, but these substances did not cause HKC cells to form cysts in collagen matrix, whereas cyst fluid did. Among other naturally occurring growth factors and autacoids, only epidermal growth factor and transforming growth factor alpha stimulated cyst formation by HKC cells; however, the capacity of cyst fluid to stimulate fluid secretion was not affected by treatment with antiserum to epidermal growth factor. It was concluded that potent, and possibly unique, substances in the cyst fluids of individuals with ADPKD support and augment biologic processes in renal epithelial cells that may be important in the promotion of progressive cyst expansion.

8-Bromo Cyclic Adenosine Monophosphate↗