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Biomedical subjects

J A Stack

Publications and source records attributed to J A Stack.

At least 19 recordsLinked to original sources
PubMed2006

Differentiation between serological responses to Brucella suis and Yersinia enterocolitica serotype O:9 after natural or experimental infection in pigs.

False-positive serological reactions (FPSR) due to infections with Yersinia enterocolitica serotype Oratio9 (YeOratio9) are a problem in tests for brucellosis. In the present study, FPSR in classical and novel tests for brucellosis following experimental infections of pigs with YeOratio9 were compared with responses of B. suis biovar 2-inoculated pigs. FPSR were limited to 2-9 weeks post-YeOratio9 inoculation, while B. suis-infected pigs were test-positive throughout the 21-week period of investigation. Although YeOratio9-inoculated pigs exhibited FPSR in Brucella tests for a limited period of time, the serological responses in a YeOratio9-purified O-antigen indirect ELISA did not decrease accordingly. Analysis of available cross-sectional serum samples from pig herds naturally infected with YeOratio9 or B. suis biovar 2 confirmed that the observed difference in the duration of the serological responses between the two infections could be used to discriminate between herds infected with B. suis biovar 2 and YeOratio9.

Animals↗
PubMed2003

Validation of FPA and cELISA for the detection of antibodies to Brucella abortus in cattle sera and comparison to SAT, CFT, and iELISA.

The fluorescence polarisation assay (FPA) is a recently described test for the serological diagnosis of Brucella infection. It has many methodological advantages over older, more established tests and can be performed in a fraction of the time. To validate the FPA, serum samples from 146 confirmed (by culture) Brucella-infected cattle were tested in conjunction with serum samples from 1947 noninfected cattle. The competitive ELISA (cELISA) was validated using these positive reference samples and 1440 negative samples, while data for the indirect ELISA (iELISA) was generated from 6957 negative samples plus the positive sera. Published diagnostic specificity (DSp) data for the complement fixation test (CFT) and serum agglutination test (SAT) was used in conjunction with the test results on the positive sera to obtain diagnostic specificity plus diagnostic sensitivity (DSn). After selection of a cutoff for the FPA and cELISA, the diagnostic specificity and sensitivity total for each test were compared. The results, with 95% confidence intervals, were: FPA (195.7+/-2.79), iELISA (195.0+/-2.70), cELISA (194.9+/-3.48), CFT (191.7+/-4.45), and SAT (180.4+/-6.33). The data presented supports the use of the FPA in diagnosis of brucellosis and questions the use of the SAT and CFT for either screening or confirmatory testing.

Agglutination Tests↗
PubMed2002

Evaluation of a selective medium for Brucella isolation using natamycin.

AIMS: To select an anti-fungal agent to replace cycloheximide in the media used for isolation of Brucella. METHODS AND RESULTS: One potential agent, natamycin, was evaluated using 28 Brucella isolates, 18 yeasts and 14 fungi. The material for the evaluation included 37 bovine milk samples, six bovine vaginal swabs and 45 milk samples artificially infected with Brucella. The recovery of Brucella only from the artificially-inoculated milk samples increased with the use of the medium containing natamycin instead of cycloheximide, at the same time significantly inhibiting the growth of yeasts, fungi and other bacteria. The inclusion of either anti-fungal agent allowed growth of the 28 Brucella isolates and totally prevented the growth of all 18 yeasts and 13 of the 14 fungi. CONCLUSIONS: Based on the results it was concluded that natamycin would be a suitable alternative to cycloheximide. SIGNIFICANCE AND IMPACT OF THE STUDY: Cycloheximide has become unavailable worldwide and is currently an anti-fungal constituent of the medium often used for isolation of Brucella organisms. The use of natamycin as a replacement in the formulation did not inhibit growth of Brucella and was effective at eliminating most contaminants.

Animals↗
PubMed2000

Allelic variation in the serotonin transporter promoter affects onset of paroxetine treatment response in late-life depression.

The relationship of the serotonin transporter gene promoter region polymorphism (5-HTTLPR) to antidepressant response was examined in 95 elderly patients receiving a protocolized treatment for depression with paroxetine or nortriptyline. Patients were treated for up to 12 weeks and assessed weekly with clinical ratings and measurements of plasma drug concentrations. Twenty-one of the paroxetine-treated subjects were found to have the ll genotype and 30 had at least one s allele. There were no baseline differences between these groups in pretreatment Hamilton Rating Scale for Depression (HRSD) scores or anxiety symptoms. During acute treatment with paroxetine, mean reductions from baseline in HRSD were significantly more rapid for patients with the ll genotype than for those possessing an s allele, despite equivalent paroxetine concentrations. Onset of response to nortriptyline was not affected. Allelic variation of 5-HTTLPR may contribute to the variable initial response of patients treated with a selective serotonin reuptake inhibitor.

Adrenergic alpha-Agonists↗
PubMed2000

Effect of nortriptyline and paroxetine on extrapyramidal signs and symptoms: A prospective double-blind study in depressed elderly patients.

Selective serotonin-reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs) have been reported to induce extrapyramidal signs and symptoms (EPS). The authors examined the change from baseline EPS, measured by an objective rating scale, in a group of elderly depressed patients participating in an ongoing randomized, double-blind comparison of nortriptyline and paroxetine. Mild baseline EPS were present in both groups. After 6 weeks of antidepressant treatment, patients in the nortriptyline group showed a significant decrease in total EPS scores. Patients in the paroxetine group showed a similar decrease in EPS from baseline, which did not reach statistical significance. There was no significant difference between nortriptyline and paroxetine in the change in EPS.

Aged↗
PubMed1999

Nortriptyline and interpersonal psychotherapy as maintenance therapies for recurrent major depression: a randomized controlled trial in patients older than 59 years.

CONTEXT: Elderly patients with major depression are at high risk for recurrence, increased mortality, and chronic disability. OBJECTIVE: To determine the efficacy of maintenance nortriptyline hydrochloride and interpersonal psychotherapy (IPT) in preventing recurrence of major depressive episodes in patients older than 59 years. DESIGN: A 2 x 2 randomized, double-blind, placebo-controlled clinical trial, stratified by therapist. SETTING: University-based psychiatric research clinic. PATIENTS: Of a total of 187 patients with recurrent nonpsychotic unipolar major depression (average age, 67 years; one third aged > or =70 years) recruited through clinical referral and media announcements, 107 were fully recovered after open acute and treatment continuation with nortriptyline and IPT. These patients were randomly assigned to 1 of 4 maintenance therapy conditions. INTERVENTIONS: Monthly medication clinic with nortriptyline hydrochloride (80-120 ng/mL steady-state levels) (n = 24); medication clinic with placebo (n = 29); monthly maintenance IPT with placebo (n = 21); and monthly maintenance IPT with nortriptyline (n = 22). MAIN OUTCOME MEASURE: Recurrence of major depressive episode. RESULTS: The time to recurrence of a major depressive episode for all 3 active treatments was significantly better than for placebo. Recurrence rates over 3 years were as follows: nortriptyline and IPT, 20% (95% confidence interval [CI], 4%-36%); nortriptyline and medication clinic visits, 43 % (95% CI, 25%-61%); IPT and placebo, 64% (95% CI, 45%-83%); and placebo and medication clinic visits, 90% (95% CI, 79%-100%). Combined treatment with nortriptyline and IPT was superior to IPT and placebo and showed a trend to superior efficacy over nortriptyline monotherapy (Wald chi2 = 3.56; P = .06). Subjects aged 70 years and older had a higher and more rapid rate of recurrence than those aged 60 to 69 years. CONCLUSION: In geriatric patients with recurrent major depression, maintenance treatment with nortriptyline or IPT is superior to placebo in preventing or delaying recurrence. Combined treatment using both appears to be the optimal clinical strategy in preserving recovery.

Adrenergic Uptake Inhibitors↗
PubMed1999

Three-year outcomes of maintenance nortriptyline treatment in late-life depression: a study of two fixed plasma levels.

OBJECTIVE: This study compared the long-term efficacy of two fixed plasma levels of nortriptyline in preventing or delaying recurrence of major depression in elderly patients and in minimizing residual depressive symptoms and somatic complaints. METHOD: The authors randomly assigned 41 elderly patients with histories of recurrent major depression to 3-year, double-blind maintenance pharmacotherapy using nortriptyline, with controlled plasma concentrations of 80-120 ng/ml versus 40-60 ng/ml. The authors compared times to, and rates of, recurrence of major depression. They also compared frequencies of side effects, noncompliance episodes, and subsyndromal symptomatic flare-ups. RESULTS: Major depressive episodes recurred for six (29%) of 21 subjects in the 80-120-ng/ml condition and eight (40%) of 20 subjects in the 40-60-ng/ml condition, a nonsignificant difference. Most recurrences took place in the first year of maintenance treatment. Hamilton depression scores in the subsyndromal range (higher than either 10 or 7) occurred significantly more often at 40-60 ng/ml, while constipation occurred significantly more often at 80-120 ng/ml. The proportions of patients reporting missed doses did not differ. CONCLUSIONS: Maintenance pharmacotherapy with nortriptyline at 80-120 ng/ml is associated with fewer residual depressive symptoms, that is, a less variable long-term response, than pharmacotherapy at 40-60 ng/ml, but constipation is more frequent and there is no difference in recurrence of syndromal major depressive episodes. Treatment at 80-120 ng/ml may be preferable, because of fewer residual symptoms and less variability of response, as long as side effect burden can be managed successfully.

Aged↗
PubMed1999

Inhibition of caffeine metabolism by estrogen replacement therapy in postmenopausal women.

This study was conducted to investigate the effect of therapeutic estrogen on cytochrome P450 1A2-mediated metabolism in postmenopausal women using caffeine as a model substrate. Twelve healthy postmenopausal women underwent estrogen replacement therapy in the form of estradiol (Estrace). Estradiol was initiated at a dose of 0.5 mg a day and titrated to achieve a steady-state plasma concentration of 50 to 150 pg/ml. Caffeine metabolic ratios (CMR; paraxanthine/caffeine) were assessed both before and after 8 weeks of estrogen replacement. For the 12 subjects, there was a mean reduction in CMR of -29.2 +/- 25.0 (p = 0.0019). Consistent with previous results found in younger women, these results indicate that exogenous estrogen in older women may inhibit CYP1A2-mediated caffeine metabolism.

Aged↗
PubMed1999

Which elderly depressed patients remain well on maintenance interpersonal psychotherapy alone?: report from the Pittsburgh study of maintenance therapies in late-life depression.

The aim of this study was to identify elderly depressed patients who can remain well on maintenance Interpersonal Psychotherapy (IPT) alone, after discontinuation of antidepressant medication. Using Cox proportional hazards models, increased severity of depression at pretreatment was associated with increased recurrence rates, to an extent greater in patients maintained on monthly IPT than in those maintained on nortriptyline. The long-term response to maintenance IPT was correctly identified in 20/25 cases by a pretreatment Hamilton score of > or = 20. Fourteen of sixteen patients with pretreatment scores of > or = 20 experienced recurrence of major depression on maintenance IPT, while 6/9 patients with pretreatment scores of less than 20 did not. (Fisher exact P = .01). The same pattern of recurrence in relation to severity was not evident in maintenance placebo, nortriptyline, or combination treatment. In addition, Hamilton scores during continuation treatment were lower (< or = 7) among those who remained well on maintenance IPT than among those who had recurrences. Elderly patients whose depressions are milder at baseline and who show excellent symptomatic remission during acute and continuation therapy may be good candidates for monthly maintenance IPT after initial successful treatment with antidepressant medication and psychotherapy.

Age Factors↗
PubMed1998

Recruitment methods for intervention research in bereavement-related depression. Five years' experience.

The authors compared various strategies for recruiting elderly subjects with bereavement-related depression into a randomized clinical trial. Over 5 years, they empaneled 65 patients from a total of 441 subjects screened (14.7%). Response to media advertisements was the single most effective strategy (54% of subjects). Another effective, but labor-intensive, strategy was using letters to bereaved spouses found through newspaper obituaries (14%); another 14% were referred by friends who had seen study advertisements. Information letters to healthcare providers yielded no study participants. Pathways to study participation did not differ as a function of race or gender and did not influence study retention or remission rates. Our experience suggests that successful intake depends on a personal mode of recruitment.

Advertising↗
PubMed1997

L-[1-(13)C] Phenylalanine oxidation as a measure of hepatocyte functional capacity in end-stage liver disease.

BACKGROUND: Liver disease is associated with impaired metabolism of these amino acids phenylalanine and tyrosine. Decreased metabolism of these amino acids leads to abnormal plasma elevations and impaired clearance rates. We have developed a noninvasive breath test that measures hepatic cytosolic enzyme activity. METHODS: The rate of hepatic phenylalanine metabolism was quantitatively calculated from the appearance of 13CO2 in the breath using the nonradioactive tracer L-[1-(13)C]phenylalanine. RESULTS: Normal controls (n = 47) oxidized phenylalanine more than twice that of end-stage liver disease patients (n = 117). Significant differences in the percent of phenylalanine oxidized per hour (mean +/- SEM) were found between controls (7.08% +/- 0.33%, 95% CI: 6.42%-7.74%) and Child Pugh classification patients, class A (4.96% +/- 0.69%, 95% CI: 3.50%-6.42%), class B (2.88% +/- 0.13, 95% CI: 2.39%-3.38%) and class C (1.75% +/- 0.13, 95% CI: 1.50%-2.01%). The phenylalanine breath test score significantly correlated with albumin levels, prothrombin time and total bilirubin. CONCLUSION: We have demonstrated that phenylalanine oxidation is significantly decreased with end-stage liver disease and is correlated with the best clinical measures of liver disease.

Adult↗
PubMed1997

Psychoeducational workshops for elderly patients with recurrent major depression and their families.

OBJECTIVE: This report details an extension of the use of psychoeducational workshops with psychiatric patients and their families to families of elderly patients with recurrent unipolar late-life depression. METHODS: Subjects were 132 participants in a study of maintenance therapies for late-life depression and their 182 family members and significant others who accepted invitations to single-session family workshops. Participants provided feedback on their satisfaction with the content and quality of the workshops. Associations between workshop attendance, preworkshop demographic and clinical characteristics, treatment adherence, and outcome were explored through comparisons between 108 patients who attended workshops and 24 patients who declined the workshop invitation. RESULTS: Favorable feedback from participants suggested that the extension of the workshops to families of elderly patients with depression was successful. Workshop attendance was associated with a lower rate of dropout during continuation treatment. CONCLUSIONS: Results associating workshop refusal and treatment dropout, as well as the overall treatment compliance and retention rates in this randomized clinical trial involving geriatric patients, support the need for further study of factors relating to elderly patients' willingness to engage in family-centered interventions.

Aged↗
PubMed1996

High-energy, high-protein, oral, liquid, nutrition supplementation in patients with HIV infection: effect on weight status in relation to incidence of secondary infection.

OBJECTIVE: to evaluate the use of high-energy, high-protein, oral, liquid, nutrition supplementation and nutrition counseling on the weight status of patients infected with the human immunodeficiency virus (HIV) with and without secondary infections. DESIGN: Prospective, descriptive, intervention trial. Follow-up clinic visits were scheduled every 1 to 3 weeks for at least 6 weeks to monitor weight, gastrointestinal symptoms, number of supplements consumed, and incidence of secondary infections. SUBJECTS/SETTING: Community-based, HIV-infected patients, with and without an acquired immunodeficiency syndrome (AIDS) defining illness, who were receiving outpatient medical care at Deaconess Hospital. Twenty-two patients enrolled; however, 4 dropped out and 1 died, so 17 were eligible for evaluation. INTERVENTION: Dietary counseling consisted of recommendations to consume a high-protein diet (1.5 g/kg ideal body weight); select foods that minimize gastrointestinal complications; and take at least one high-energy, high-protein, oral, liquid, nutrition supplement daily. MAIN OUTCOME MEASURES: Energy intake from the supplements and weight change over time in relation to whether a secondary infection occurred. STATISTICAL ANALYSIS: Means, standard deviations, and frequency. RESULTS: At the time of entry to the study, the patients with preexisting weight loss (16 of 17) were 14+/-8% below their usual body weight. On average, patients consumed 11+/-4 supplements per week for 6+/-3 weeks. The majority (12 of 17) were able to gain or maintain weight. Overall weight change was 1.1+/-2.2 kg. Only 5 of 17 patients lost weight, 4 of whom developed a secondary infection during the study (ie, after enrollment in the study). All of those who developed a secondary infection were classified as having AIDS and had lower mean CD4 counts at baseline than those who did not develop a secondary infection. Although those who developed a secondary infection had a higher incidence of weight loss, their consumption of oral supplements per week was greater than that of those without a secondary infection. APPLICATIONS/CONCLUSIONS: In patients with HIV infection and in the early stages of AIDS without a secondary infection, weight gain and/or maintenance was achievable with a high-energy, high-protein, oral, liquid, nutrition supplement in conjunction with nutrition counseling. The majority of the patients who developed a secondary infection, however, lost weight despite the use of supplements and counseling. Use of a high-energy, high-protein, oral, liquid, nutrition supplement, with intact nutrients, should be the first-line nutrition treatment for malnourished, HIV-infected patients without secondary infections.

AIDS-Related Opportunistic Infections↗
PubMed1995

Does recruitment method make a difference? Effects on protocol retention and treatment outcome in elderly depressed patients.

The specific aim of this study was to contrast effects of recruitment method (solicited, referred) on demographic, psychosocial, medical, and treatment outcome measures in an ongoing clinical trial of maintenance therapies in late-life depression. Data from 125 elderly patients (56 solicited via media campaign, 69 clinically referred) with recurrent, unipolar major depression were available for analysis. Several statistical contrast procedures, including group t tests, chi 2 tests, survival analysis, and logistic regression, were used to assess differences in patient profiles related to method of recruitment. Referred patients included a higher proportion of African Americans and had a lower level of education, fewer economic resources, and higher chronic medical burden. Solicited patients had been in the index episode longer than the referred patients at the time of protocol entry and were 3.4 times more likely to have experienced a "provoking agent" (severe life event or chronic difficulty) during the 6 months that preceded the onset of depressive symptoms. In contrast to these demographic and illness history differences, there were no differences in treatment response rates or time to response related to recruitment method. Solicited patients had an overall treatment response rate of 71% versus 62% in the referred group. Median time to response was 14.3 weeks in the solicited group and 13.6 weeks in the referred group. These results suggest that the inclusion of solicited patients in geriatric depression clinical trials does not bias short-term treatment outcome.

Adjustment Disorders↗
PubMed1995

Generic enteral formulas: a new idea for the 1990s.

Generic equivalent enteral formulas are now commercially available. The purpose of this article is threefold: (1) to define generic equivalents and compare both their nutritional and monetary differences with brand name products, (2) to provide the clinician with factors to consider when evaluating generic formulas--the source and distribution of macronutrients and micronutrients, and patient tolerance, nutritional status and outcome--and (3) to provide information on how to incorporate generic enteral formulas onto an institution's enteral formulary. In today's environment of diminishing health care budgets, generic enteral formulas can play a role in cost containment without sacrificing quality nutritional care.

Aged↗
PubMed1994

Hopelessness in suicide attempters after acute treatment of major depression in late life.

The relation between hopelessness and suicide attempts in the elderly was examined by studying the course of hopelessness in depressed patients. Sixty-three elderly patients with recurrent major depression were treated with nortriptyline and interpersonal psychotherapy and underwent serial ratings of hopelessness and depression during the acute and continuation phases of treatment. Patients who had made a suicide attempt in the past had significantly higher hopelessness scores than nonattempters during both phases of treatment. They were also more likely to drop out of treatment. A high degree of hopelessness persisting after remission of depression in elderly patients appears to be associated with a history of suicidal behavior. It may also increase the likelihood of premature discontinuation of treatment and lead to future suicide attempts or suicide.

Age Factors↗
PubMed1992

Rating chronic medical illness burden in geropsychiatric practice and research: application of the Cumulative Illness Rating Scale.

Reliable quantitative ratings of chronic medical illness burden have proved to be difficult in geropsychiatric practice and research. Thus, the purpose of the study was to demonstrate the feasibility and reliability of a modified version of the Cumulative Illness Rating Scale (CIRS; Linn et al., 1968) in providing quantitative ratings of chronic illness burden. The modified CIRS was operationalized with a manual of guidelines geared toward the geriatric patient and for clarity was designated the CIRS(G). A total of 141 elderly outpatient subjects (two medical clinic groups of 20 each, 45 recurrent depressed subjects, 21 spousally bereaved subjects, and 35 healthy controls) received comprehensive physical examinations, reviews of symptoms, and laboratory testing. These data were then used by nurse practitioners, physician's assistants, and geriatric psychiatrists to compute CIRS(G) ratings of chronic illness burden. As hypothesized, analysis of variance demonstrated significant differences among groups with respect to total medical illness burden, which was highest among medical clinic patients and lowest in control subjects. Good interrater reliability (i.e., intraclass correlations of 0.78 and 0.88 in a subsample of 10 outpatients and a separate group of 10 inpatients, respectively) was achieved for CIRS(G) total scores. Among medical clinic patients, a significant correlation was found, as expected, between CIRS(G) chronic illness burden and capability as quantified by the Older Americans Activities of Daily Living Scale; and between CIRS(G) scores and physicians' global estimates of medical burden. Finally, with repeated measures of illness burden approximately 1 year from symptom baseline, significant rises were detected, as expected. The current data suggest that the CIRS(G) can be successfully applied in medically and psychiatrically impaired elderly subjects, with good interrater reliability and face validity (credibility).

Activities of Daily Living↗