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Biomedical subjects

V Shane Pankratz

Publications and source records attributed to V Shane Pankratz.

At least 37 records · Page 2Linked to original sources
PubMed2005

Human leukocyte antigen class II alleles and rubella-specific humoral and cell-mediated immunity following measles-mumps-rubella-II vaccination.

We examined associations between human leukocyte antigen (HLA) class II genes and both rubella-specific immunoglobulin G antibodies and lymphoproliferative responses after measles-mumps-rubella-II (MMR-II) vaccination, in a population-based sample of 346 schoolchildren. The DPB1*0301, DPB1*0401, DPB1*1301, and DPB1*1501 alleles were significantly associated with rubella vaccine-induced antibodies. Alleles suggestive of being positively associated with rubella-specific lymphoproliferative stimulation indices were DPB1*0301, DQB1*0501, DRB1*0101, and DRB1*1104. Conversely, the DPB1*0401, DPB1*1001, DPB1*1101, DQB1*0202, and DRB1*0701 alleles were negatively associated with rubella-specific lymphoproliferation. This study of HLA class II-restricted humoral and cellular immune responses to rubella provides significant insight into mechanisms of vaccine response and new vaccine development.

Adolescent↗
PubMed2005

The lifetime risk of suicide in schizophrenia: a reexamination.

BACKGROUND: The psychiatry literature routinely quotes a lifetime schizophrenia suicide prevalence of 10% based on 1 meta-analysis and 2 studies of chronic schizophrenics. OBJECTIVES: To build a methodology for extrapolating lifetime suicide prevalence estimates from published cohorts and to apply this approach to studies that meet inclusion criteria. DATA SOURCES: We began with a MEDLINE search (1966-present) for articles that observed cohorts of schizophrenic patients. Exhaustive bibliography searching of each identified article brought the total number of articles reviewed to 632. STUDY SELECTION: Studies included in the meta-analysis observed a cohort of schizophrenic patients for at least 2 years, with at least 90% follow-up, and reported suicides. Articles are excluded for systematic age bias (ie, adolescents). DATA EXTRACTION: Extracted data included sample size, number of deaths, number of suicides, percentage of follow-up, and diagnostic system used. Data were extracted independently by 2 of us, and differences were resolved by consensus after re-review. DATA SYNTHESIS: Studies were divided into 2 groups: 32 studies of schizophrenics enrolled at various illness points (25 578 subjects) and 29 studies of schizophrenics identified at either illness onset or first admission (22 598 subjects). Regression models of the intersection of proportionate mortality (the percentage of the dead who died by suicide) and case fatality (the percentage of the total sample who died by suicide) were used to calculate suicide risk in each group. The estimate of lifetime suicide prevalence in those observed from first admission or illness onset was 5.6% (95% confidence interval, 3.7%-8.5%). Mixed samples showed a rate of 1.8% (95% confidence interval, 1.4%-2.3%). Case fatality rates showed no significant differences when studies of patients diagnosed with the use of newer systems were compared with studies of patients diagnosed under older criteria. CONCLUSION: This study estimates that 4.9% of schizophrenics will commit suicide during their lifetimes, usually near illness onset.

Age of Onset↗
PubMed2005

Random-effects Cox proportional hazards model: general variance components methods for time-to-event data.

Proportional hazards regression models are commonly used to study factors associated with time-to-event data. Because many complex genetic diseases exhibit variation in age at onset, it is important to have the capability to perform survival analyses on data collected from individuals whose observations are correlated due to shared genes or environment. While there are widely accepted methods for variance components analysis for simple quantitative traits, a parallel methodology for survival data has not been available. This manuscript outlines a method to perform variance component analyses under general random effects proportional hazards models. This method is based on a Laplace approximation, and makes computation for correlated time-to-event data feasible. The correlated frailty models described here can be used to perform genetic analyses, and other analyses with structured random effects, on age-at-onset data in a manner analogous to standard variance components methods for quantitative traits. We illustrate the use of the method by examining the heritability of breast cancer in a large familial cohort study. We also perform variance components linkage analyses on data simulated for the Twelfth Genetic Analysis Workshop (GAW12), and further examine the performance of this method for linkage analysis in a simulation study. The breast cancer analyses support significant heritability of disease age-at-onset that is of moderate size. The variance component linkage analyses successfully identify the location of the disease genes that were simulated to have a direct impact on age-at-onset. The methods outlined here make it possible to perform general variance components analyses on time-to-event endpoints, even on large data sets, in a computationally efficient manner.

Age of Onset↗
PubMed2005

Correlates of lymphoproliferative responses to measles, mumps, and rubella (MMR) virus vaccines following MMR-II vaccination in healthy children.

Cell-mediated immunity (CMI) to measles, mumps, and rubella viral antigens plays a critical role in providing long-term protection against these infectious diseases. We examined CMI by measuring lymphoproliferative response induced in response to stimulation with the above three antigens following two doses of measles, mumps, and rubella-II (MMR-II) vaccine in a randomly selected, population-based cohort of healthy children. We determined if a correlative and predictive intraclass relationship exists between CMI to the three components of MMR-II. We detected positive lymphoproliferative responses to measles, mumps, and rubella vaccines. Mumps vaccine used as an antigen had the highest median stimulation index followed by measles and rubella vaccines. The overall intraclass correlation value for lymphoproliferative response to measles, mumps, and rubella using Pearson's correlation was 0.61 (95% confidence interval = 0.56, 0.66). We observed a significant pairwise association to individual vaccine components between subjects in the upper and lower 10th percentile of immune response. This study demonstrates recall CMI post-MMR-II vaccination with significant intraclass correlation among the CMI responses to the three vaccine components.

Adolescent↗
PubMed2005

Extinction of the human leukocyte antigen homozygosity effect after two doses of the measles-mumps-rubella vaccine.

We have reported associations between human leukocyte antigen (HLA) homozygosity and low measles antibody levels after one dose of the measles, mumps, and rubella (MMR) vaccine. Here, we examined associations between HLA homozygosity and immune responses to MMR after two doses of vaccine. We examined associations between HLA homozygosity and measles antibody levels in a group of 178 children (cohort 1) as well as associations between homozygosity and antibody levels and lymphoproliferative responses to MMR in 346 children (cohort 2). In cohort 1, HLA homozygotes and heterozygotes had similar increases in measles antibody levels after a second dose of measles vaccine. In cohort 2, HLA homozygosity was not associated with measles immune measures after two doses of vaccine. Homozygosity at the DPB locus was associated with increased rubella antibody levels, and homozygosity at the class IA alleles was associated with lower mumps lymphoproliferative response. Homozygosity at increasing numbers of loci was also associated with lower mumps antibody levels and lymphoproliferative response. Therefore, two doses of the MMR vaccine appear to induce sufficient antibody levels and lymphoproliferative responses against measles and rubella, regardless of HLA homozygosity status. However, children who are HLA homozygous may be less protected against mumps compared with children who are heterozygous.

Antibodies↗
PubMed2005

Haplotype analysis improves molecular diagnostics of autosomal recessive polycystic kidney disease.

BACKGROUND: Autosomal recessive polycystic kidney disease (ARPKD) is characterized by wide phenotypic variability, ranging from in utero detection with enlarged, echogenic kidneys to an adult presentation with congenital hepatic fibrosis. The ARPKD gene, PKHD1 , covers about 470 kb of DNA (67 exons), and mutation studies have found marked allelic heterogeneity with a high level of novel missense changes and neutral polymorphisms. To improve the prospects for molecular diagnostics and to study the origin of some relatively common mutations, the authors have developed a strategy for improved ARPKD haplotyping. METHODS: A protocol of multiplex PCR and fluorescence genotyping in a single capillary has been developed to assay 7 highly informative simple sequence repeat (SSR) markers that are intragenic or closely flanking PKHD1. RESULTS: Examples in which haplotype analysis, used in combination with mutation screening, improved the utility of molecular diagnostics, especially in families in which just a single PKHD1 mutation has been identified, are illustrated. The new markers also allow screening for larger DNA deletions, detecting unknown consanguinity and exploring the disease mechanism. Analysis of 8 recurring mutations has shown likely common haplotypes for each, and the divergence from the ancestral haplotype, by recombination, can be used to trace the history of the mutation. The common mutation, T36M, was found to have a single European origin, about 1,225 years ago. CONCLUSION: Improved haplotype analysis of ARPKD complements mutation-based diagnostics and helps trace the history of common PKHD1 mutations.

3' Flanking Region↗
PubMed2005

Women with diabetes have poorer control of blood pressure than men.

OBJECTIVE: Diabetes is associated with a higher coronary heart disease (CHD) mortality in women compared with men. Less aggressive control of the CHD risk factors in women can contribute to this excess mortality. Because hypertension has a high prevalence in subjects with diabetes, we compared the control of this risk factor between men and women. METHODS: This was a retrospective cohort study comparing blood pressure levels and trends over a 1-year period between men and women with diabetes receiving primary care. Using a chronic disease registry database, subjects with type 1 and type 2 diabetes, aged >or=18, were identified for inclusion. Mean weighted systolic blood pressure (SBP) and diastolic blood pressure (DBP) were calculated for subjects with multiple longitudinal readings. Subjects were classified into four blood pressure control categories based on the mean weighted blood pressure. Comparisons were made between men and women before and after controlling for baseline characteristics. RESULTS: A total of 3181 subjects (46% women) were included in the study. More women than men were in the moderate and severely elevated blood pressure categories (40% and 6% compared with 32% and 5%, respectively, p<0.001). The unadjusted mean SBP was 3 mm Hg higher in women (139 mm Hg in women compared with 136 in men, p<0.001). These differences remained significant after controlling for baseline variables. CONCLUSIONS: In subjects with diabetes receiving medical care, women had poorer control of blood pressure and a significantly higher mean SBP compared with men. These findings might partially explain the excess CHD mortality in women with diabetes.

Adult↗
PubMed2005

Analysis of hypocretin (orexin) antibodies in patients with narcolepsy.

STUDY OBJECTIVES: We tested the hypothesis that patients with narcolepsy have serum antibodies specific for preprohypocretin and its derivatives. DESIGN: We tested sera from strictly diagnosed HLA DQB1*0602-positive narcoleptic patients with cataplexy for evidence of autoantibodies against human preprohypocretin, hypocretin 1 and 2, N-terminal leader and C-terminal peptides of preprohypocretin using enzyme-linked immunosorbent assays (ELISA). These results were compared to samples from nonnarcoleptic psychiatric and sleep apnea controls. Laboratory personnel were blinded to subject status. SETTING: Narcoleptic patients and nonnarcoleptic controls were recruited from the Mayo Clinic facilities in Rochester, Minnesota; Scottsdale, Arizona; and Jacksonville, Florida. Laboratory testing was conducted in the Mayo Psychogenomic Laboratory at the Rochester Mayo Clinic. PARTICIPANTS: A sample of 34 narcoleptic patients and 49 nonnarcoleptic controls. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: ELISA measurements were in optical density. Primary analyses were of the entire narcoleptic and control groups for each potential antigen, and none of the differences reached P values required for significance after Bonferroni adjustment. Secondary analyses by age and sex yielded P values that were significant after Bonferroni adjustment in only 2 cases, but further statistical analyses cast doubt on the veracity of these differences. In all cases where a significant difference was recorded, the hypothesis was not supported because the control optical density reading was higher than the narcoleptic values. CONCLUSIONS: These ELISA assay results do not support the hypothesis that HLA DQB1*0602-positive narcolepsy with cataplexy is associated with serum antibodies against preprohypocretin or its cleavage products.

Autoantibodies↗
PubMed2005

Risks of high-dose stimulants in the treatment of disorders of excessive somnolence: a case-control study.

STUDY OBJECTIVES: To ascertain complications associated with high-dose stimulant therapy in patients with narcolepsy or idiopathic hypersomnia. DESIGN: Case-control, retrospective chart review. SETTING: Sleep center in an academic hospital. PATIENTS: 116 patients with narcolepsy or idiopathic hypersomnia were individually matched by sex, diagnosis, age of onset, and duration of follow-up from both onset and diagnosis. Members of the high-dose group (n = 58) had received at least 1 stimulant at a dosage > or = 120% of the maximum recommended by the American Academy of Sleep Medicine Standards of Practice Committee. The standard-dose control group (n = 58) had received stimulants at a dosage < or = 100% of the American Academy of Sleep Medicine guidelines. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: The prevalence of psychosis (odds ratio = 12.0 [1.6-92.0]), alcohol or polysubstance misuse (odds ratio = 4.3 [1.2-15.2]), and psychiatric hospitalization (odds ratio = 3.2 [1.1-10.0]) was significantly increased in the high-dose group. More high-dose patients also experienced tachyarrhythmias (odds ratio = 3.3 [0.92-12.1] and anorexia or weight loss (odds ratio = 11.0 [1.4-85.2]). The frequency of physician-diagnosed depression, drug-seeking and suicide-related behaviors, hypertension, and cardiovascular disease did not differ significantly between the groups. CONCLUSIONS: This study demonstrated a significantly higher occurrence of psychosis, substance misuse, and psychiatric hospitalizations in patients using high-dose stimulants compared to those using standard doses. Tachyarrhythmias and anorexia or weight loss were also more common in this group as compared with controls. Clinicians should be very cautious in prescribing dosages that exceed maximum guidelines.

Adult↗
PubMed2005

Web-based learning in residents' continuity clinics: a randomized, controlled trial.

PURPOSE: To determine whether internal medicine residents prefer learning from Web-based (WB) modules or printed material, and to compare the effect of these teaching formats on knowledge. METHOD: The authors conducted a randomized, controlled, crossover study in the internal medicine resident continuity clinics of the Mayo School of Graduate Medical Education during the 2002-03 academic year. Participants studied two topics of ambulatory medicine using WB modules and two topics using paper practice guidelines in randomly assigned sequences. Primary outcomes were format preference (assessed by an end-of-course questionnaire) and score changes from pre- to postintervention tests of knowledge. RESULTS: A total of 109 consented and 75 (69%) completed the postintervention test. Fifty-seven of 73 (78% [95% CI, 67-86%]) preferred the WB format (p < .001). Test scores improved for both formats (67.7% to 75.0% for WB, 66.0% to 73.3% for paper), but score change was not different between formats both before (p = .718) and after (p = .080) adjusting for topic, clinic site, study group, postgraduate year, and gender. Residents spent less time on WB modules (mean = 47 +/- 26 minutes) than paper (mean = 59 +/- 35, p = .024). Difficulties with passwords limited their use of WB modules for 71% (59-80%) of residents. CONCLUSION: No difference was found between WB and paper-based formats in knowledge-test score change, but residents preferred learning with WB modules and spent less time doing so. Passwords appeared to impede use of WB modules. WB learning is effective, well accepted, and efficient. Research should focus on aspects of WB instruction that will enhance its power as a learning tool and better define its role in specific settings.

Attitude of Health Personnel↗
PubMed2005

Monitoring intravesical therapy for superficial bladder cancer using fluorescence in situ hybridization.

PURPOSE: We evaluated fluorescence in situ hybridization (FISH) for assessing the response to therapy in patients with superficial bladder cancer receiving bacillus Calmette-Guerin or other intravesical therapies. MATERIALS AND METHODS: A total of 37 patients receiving intravesical therapy for superficial bladder cancer were enrolled in this study. Urine specimens were collected for FISH analysis just prior to the first intravesical therapy in 31 cases and just prior to or within 2 months following the last intravesical therapy in 37. FISH was done using the UroVysion probe set (Abbott Laboratories, Abbott Park, Illinois) with results considered positive if 5 or more cells demonstrated polysomy. Biopsy, cystoscopy and/or cytology results were then compared to FISH results to evaluate the usefulness of the test for monitoring intravesical therapy. RESULTS: Of the patients 25 had a negative and 12 had a positive post-therapy FISH result. All 12 patients with a positive post-therapy FISH result had tumor recurrence, while tumor recurrence was observed in 13 of the 25 with a negative post-therapy FISH result (HR 4.6, 95% CI 1.9 to 11.1, p <0.001). Of the patients with tumor recurrence 7 of 12 with a positive post-therapy FISH result had muscle invasive tumor and 2 of 25 with a negative post-therapy FISH result had muscle invasive tumor (HR 9.4, 95% CI 1.9 to 45.3, p = 0.001). CONCLUSIONS: FISH appears to be useful for monitoring patients with superficial bladder cancer for the response to intravesical therapy. Patients with a positive FISH result at the end of treatment are at high risk for progression to muscle invasive bladder cancer.

Adjuvants, Immunologic↗
PubMed2005

Prenatal and perinatal correlates of adult mammographic breast density.

BACKGROUND: Adult mammographic percent density is one of the strongest known risk factors for breast cancer. In utero exposure to high levels of endogenous estrogens (or other pregnancy hormones) has been hypothesized to increase breast cancer risk in later life. We examined the hypothesis that those factors associated with higher levels of estrogen during pregnancy or shortly after birth are associated with higher mammographic breast density in adulthood. METHODS: We analyzed data on 1,893 women from 360 families in the Minnesota Breast Cancer Family Study who had screening mammograms, risk factor data, over age 40, and no history of breast cancer. Prenatal and perinatal risk factor data were ascertained using a mailed questionnaire. Mammographic percent density and dense area were estimated from the mediolateral oblique view using Cumulus, a computer-assisted thresholding program. Linear mixed effects models incorporating familial correlation were used to assess the association of risk factors with percent density, adjusting for age, weight, and other breast cancer risk factors, all at time of mammography. RESULTS: The mean age at mammography was 60.4 years (range, 40-91 years), and 76% were postmenopausal. Among postmenopausal women, there was a positive association of birthweight with percent density (P trend <0.01), with an adjusted mean percent density of 17.1% for <2.95 kg versus 21.0% for > or = 3.75 kg. There were suggestive positive associations with gestational age (mean percent density of 16.7% for preterm birth, 20.2% for term birth, and 23.0% for late birth; P trend = 0.07), maternal eclampsia/preeclampsia (mean percent density of 19.9% for no and 14.6% for yes; P = 0.16), and being breast-fed as an infant (mean percent density of 18.2% for never and 20.0% for ever; P = 0.08). There was no association of percent density with maternal age, birth order, maternal use of alcohol or cigarettes, or neonatal jaundice. Except for being breast-fed, these associations showed similar but attenuated trends among premenopausal women, although none were statistically significant. The results for dense area paralleled the percent density results. The associations of gestational age and being breast-fed as an infant with percent density attenuated when included in the same model as birthweight. CONCLUSIONS: Birthweight was positively associated with mammographic breast density and dense area among postmenopausal women and more weakly among premenopausal women, suggesting that it may be a marker of this early life exposure. These results offer some support to the hypothesis that pregnancy estrogens or other pregnancy changes may play a role in breast cancer etiology, and suggest that these factors may act in part through long-term effects on breast density.

Adult↗
PubMed2005

Estrogen bioactivation, genetic polymorphisms, and ovarian cancer.

Recent experimental evidence has shown that catechol estrogens can be activated through metabolism to form depurinating DNA adducts and thereby initiate cancer. Limited data are available regarding this pathway in epithelial ovarian cancer. We conducted a case-control study of 503 incident epithelial ovarian cancer cases at the Mayo Clinic in Rochester, MN, and Jacksonville, FL, and a 48-county region in North Carolina. Six hundred nine cancer-free controls were frequency matched to the cases on age, race, and residence. After an interview to obtain data on risk factors, a sample of blood was collected for DNA isolation. Subjects were genotyped for seven common single nucleotide polymorphisms in four genes involved in catechol estrogen formation (CYP1A1 and CYP1B1) or conjugation (COMT and SULT1A1). Data were analyzed using logistic regression, stratified by race, and with adjustment for design factors and potential confounders. None of the individual genotypes were significantly associated with ovarian cancer risk. However, an oligogenic model that considered the joint effects of the four candidate genes provided evidence for an association between combinations of these genes and ovarian cancer status (P = 0.015). Although preliminary, this study provides some support for the hypothesis that low-penetrance susceptibility alleles may influence risk of epithelial ovarian cancer.

Adult↗
PubMed2005

Preventive health behaviors and familial breast cancer.

AIM: To examine medical and lifestyle preventive behaviors among women with varying levels of familial breast cancer risk. METHODS: Using cross-sectional data from the Minnesota Breast Cancer Family Study, a historical cohort of 426 families, we compared medical (mammography adherence, antiestrogen use, and prophylactic surgery) and lifestyle (physical activity, smoking, alcohol, and diet) behaviors across three groups of cancer-free women ages 18 to 95 defined by their family history of breast cancer. Family history was classified as high-risk, moderate-risk, or average to low-risk depending on the number and degree of relationship of family members with breast cancer. RESULTS: After adjusting for age and education, high-risk women were twice as likely to have ever used an antiestrogenic agent (9.0% versus 4.6% among moderate-risk and 4.1% among average to low-risk; P = 0.002). Among women ages <40, the high-risk group were more likely to have ever had a mammogram (82% versus 47% among moderate-risk and 35% among average to low-risk; P < 0.001). Average to low-risk women were the least likely to be current smokers and high-risk women may consume slightly fewer fruits and vegetables compared with the other groups, but there were no other differences in lifestyle behaviors, including physical activity and alcohol use. CONCLUSIONS: Women with strong family histories of breast cancer are more likely to undertake medical but not lifestyle preventive behaviors.

Adult↗
PubMed2005

Psychiatric manifestations of Creutzfeldt-Jakob disease: a 25-year analysis.

This study characterizes the type and timing of psychiatric manifestations in sporadic Creutzfeldt-Jakob disease (sCJD). Historically, sCJD has been characterized by prominent neurological symptoms, while the variant form (vCJD) is described as primarily psychiatric in presentation and course: A retrospective review of 126 sCJD patients evaluated at the Mayo Clinic from 1976-2001 was conducted. Cases were reviewed for symptoms of depression, anxiety, psychosis, behavior dyscontrol, sleep disturbances, and neurological signs during the disease course. Eighty percent of the cases demonstrated psychiatric symptoms within the first 100 days of illness, with 26% occurring at presentation. The most commonly reported symptoms in this population included sleep disturbances, psychotic symptoms, and depression. Psychiatric manifestations are an early and prominent feature of sporadic CJD, often occurring prior to formal diagnosis.

Adult↗
PubMed2004

Associations between human leukocyte antigen (HLA) alleles and very high levels of measles antibody following vaccination.

Associations between human leukocyte antigen (HLA) genes and very high levels of antibodies (or hyperseroresponsiveness) to measles antigens in a genetically heterogeneous human population are poorly understood. We studied the association between antibody levels after measles vaccination and HLA class I and II alleles among 170 US schoolchildren who received one dose of measles-mumps-rubella II vaccine. Vaccine recipients were divided into two groups: 93 recipients who were seropositive and 77 recipients who were hyperseropositive (the upper 10th percentile of antibody levels of all subjects). Out of all the alleles analyzed, HLA-B(*)7 (odds ratio (OR) 1.9; P = 0.05), DQA1(*)0104 (OR 4.6; P = 0.02) and DPA1(*)0202 (OR 4.8; P = 0.04) alleles were positively associated with hyperseropositivity, whereas HLA-B(*)44 (OR 0.4; P = 0.02), DRB1(*)01 (OR 0.6; P = 0.09), DRB1(*)08 (OR 0.3; P = 0.04), DQB1(*)0301 (OR 0.5; P = 0.04), and DPB1(*)0401 (OR 0.6; P = 0.03) alleles were negatively associated with hyperseropositivity. The alleles B(*)44, DRB1(*)01, DRB1(*)08 and DQA1(*)0104 remained statistically significant after accounting for the effects of other alleles. The results suggest that HLA alleles have important associations with measles antibody hyperseropositivity. These data increase our understanding of measles vaccine-induced immune response and will be useful for future mechanistic work on measles virus antigen processing and presentation in seronegative and hyperseropositive individuals.

Alleles↗