Biomedical subjects

Amy L Weaver

Publications and source records attributed to Amy L Weaver.

62 records · Page 4Linked to original sources

PubMed2002

Comparison of standardized and nonstandardized nuclear grade of renal cell carcinoma to predict outcome among 2,042 patients.

We compared the ability of original nuclear grades from surgical pathology reports and grades reviewed by a urologic pathologist to predict death due to renal cell carcinoma (RCC) for 2,042 patients treated with radical nephrectomy between January 1970 and December 1998. Reviewed grade I tumors had small, round nuclei with inconspicuous nucleoli visible at x400; grade 2 contained round to slightly irregular nuclei with mildly enlarged nucleoli visible at x200; grade 3 had round to irregular nuclei with prominent nucleoli visible at x100; grade 4 contained enlarged pleomorphic or giant cells. Predictive abilities were compared using R2 values from Cox proportional hazards models. There were 1,733 (84.87%) clear cell, 222 (10.87%) papillary, and 87 (4.26%) chromophobe tumors. Reviewed grades were more predictive of death due to RCC than original grades for clear cell (R2, 21% vs 16%), papillary (R2, 16% vs 13%), and chromophobe (R2, 39% vs 27%) RCC. Among patients with clear cell and papillary RCC, this difference was apparent even after adjusting for the 1997 TNM stage. Standardized nuclear grades were more predictive of death due to RCC than nonstandardized grades for all subtypes studied.

Carcinoma, Renal Cell↗

PubMed2002

Squamous cell carcinoma of the tonsils: a molecular analysis of HPV associations.

BACKGROUND: The role of human papilloma virus (HPV) in the pathogenesis and biological behavior of tonsillar squamous cell carcinoma (TSCC) are areas of intense investigation. METHODS: This study used PCR analysis to identify HPV in paraffin-embedded tonsillar and nodal tissue from 52 patients with TSCC and 48 age (+/-5 year)/gender-matched controls with benign tonsillar hyperplasia. Results were correlated with HLA-DRB1 haplotype and clinical outcome. RESULTS: HPV was identified in 46% of patients with TSCC and 6% of controls. DNA sequencing showed the presence of HPV type 16 in 21 patients (40%) with TSCC. There was no statistically significant association between HLA-DRB1 expression and TSCC or HPV infection. Fifteen of 16 patients with HPV-positive TSCC with regional metastases had evidence of HPV in pathologically involved lymph nodes. In eight HPV 16-positive TSCC patients with lymph node metastasis, PCR testing identified HPV 16 in 17 of 23 histologically negative lymph nodes. Patients with HPV-positive TSCC without metastatic disease had no evidence of HPV in their lymphatic tissue. Clinically, HPV-associated carcinoma was present in younger patients in comparison with HPV-negative TSCC patients (mean age, 56.6 versus 66 years; P = 0.001). The odds for patients with HPV infection to develop TSCC were 18.2 times greater than for patients without HPV infection (95% confidence interval 4.6, 73.1). There was no statistically significant association between presence of HPV and cause-specific survival (hazard ratio = 2.5 for HPV negative versus positive; P = 0.26), after adjusting for age in a Cox proportional hazards regression analysis. CONCLUSION: HPV is an independent risk factor for TSCC. Identification of HPV in the histologically positive and negative lymph nodes of patients with HPV-positive TSCC/metastatic disease supports the role of HPV in the oncogenesis of TSCC.

Adult↗

PubMed2002

The influence of pNx/pN0 grouping in a multivariate setting for outcome modeling in patients with clear cell renal cell carcinoma.

PURPOSE: Lymphadenectomy, especially extended lymphadenectomy, is not commonly performed in patients undergoing a radical nephrectomy for clear cell renal cell carcinoma. Surgeons may sample suspicious regional lymph nodes, but the lymph node status of many patients with renal cell carcinoma remains unknown, termed stage pNx. Outcome models based on large institutional reviews have been criticized for grouping stages pNx and pN0 cases because of concern that the pNx category may include unrecognized stages pN1/pN2 disease. We evaluated cancer specific survival differences in patients with clear cell renal cell carcinoma and a lymph node stage of pNx, pN0 or pN1/pN2. MATERIALS AND METHODS: We searched the registry at our institution for patients who underwent radical nephrectomy for clear cell histology renal cell carcinoma between 1970 and 1998. Those with distant metastases at surgery were excluded from study. Clinical features obtained from the medical record included age at surgery, history of tobacco use, hypertension and symptomatic disease at presentation. A single urological pathologist reviewed all tumor specimens for nuclear grade, tumor necrosis, surgical margin status, 1997 tumor stage and lymph node status. These features were compared in patients with stages pNx and pN0 tumors. Cox proportional hazards models were used to compare cancer specific survival in univariate fashion, and after adjusting for tumor stage and grade. RESULTS: The study cohort consisted of 1,535 patients with sporadic, unilateral clear cell renal cell carcinoma who underwent radical nephrectomy. There were 600 patients (39%) with stage pNx, 870 (57%) with stage pN0 and 65 (4%) with stages pN1/pN2 tumors. At an average of 4.2 years after surgery 414 patients died of renal cell carcinoma. On univariate analysis patients with stage pN0 tumors were significantly more likely to die of renal cell carcinoma than those with stage pNx tumors (risk ratio 1.40, 95% confidence interval 1.12 to 1.75, p = 0.003). However, after adjusting for tumor stage and nuclear grade the difference in outcome for stages pNx and pN0 tumors was not statistically significant (risk ratio 1.07 95% confidence interval 0.85 to 1.34, p = 0.583). Patients with stage pNx disease were significantly less likely to be symptomatic at presentation (p = 0.002), have tumors that were less than 5 cm. (p <0.001) and of lower stage (p <0.001) and grade (p = 0.005), and to have tumors with necrosis (p = 0.024) than patients with stage pN0 disease. CONCLUSIONS: Combining stages pNx and pN0 cases to create outcome prediction models after radical nephrectomy for clear cell renal cell carcinoma is appropriate in a multivariate setting that includes tumor stage and grade. Clinical features available preoperatively and during surgery can help guide the decision to perform limited lymph node sampling. When the tumor is 5 cm. or greater, shows pathological necrosis or is advanced grade 3 or 4, lymph node sampling adds little prognostic information.

Adult↗

PubMedDate not supplied

Emergency department use and costs for youth with attention-deficit/hyperactivity disorder: associations with stimulant treatment.

OBJECTIVE: To investigate whether, among youth with attention-deficit/hyperactivity disorder (ADHD), stimulant treatment is associated with reduced emergency department (ED) use and medical costs. METHODS: We previously reviewed the complete and detailed school and medical records of all individuals born 1976-1982 in Rochester, Minn, to identify those who met criteria for ADHD between age 5 years and emigration from the area. Stimulant treatment (all start/stop dates, dosages) was also abstracted. This study followed birth cohort members with ADHD in provider-linked billing data from January 1, 1987 (billing data first available), to age 18 for outcomes: ED visits, ED costs, and medical costs. For each outcome, we analyzed associations with 1) any stimulants (yes/no), 2) proportion of follow-up time on stimulants, and 3) among those treated with stimulants, periods on versus off stimulants. RESULTS: Of 313 youth with ADHD, 231 (74%) received any stimulants; treatment duration ranged from 14 days to 11.8 years. Treated and untreated youth were similar with respect to median annual ED visits (0.5 vs 0.5) and medical costs (661 US dollars vs 741 US dollars) (P > .05); however, increasing proportion of follow-up on stimulants was associated with fewer ED visits (P= .02) and higher medical costs (P< .001). The 231 treated youth experienced an average of 3.7 periods on and off stimulants; while receiving stimulants, they exhibited fewer ED visits (P= .02), lower ED costs (P = .03), and higher medical costs (P< .001) compared with periods off stimulants. CONCLUSIONS: Among youth with ADHD, extended stimulant treatment is associated with decreased ED visits and ED costs, but higher total medical costs.

Adolescent↗

PubMedDate not supplied

The use of population and database resources in outcome-based research.

Many patient management decisions an otolaryngologist makes every day stem from good patient- and population-based evidence. This paper will explore the topic of population/database research and how these studies are useful. We also examine the current literature on this subject, explore the strengths and weaknesses of these studies and provide information on the practical aspects of performing this type of research. Overall, this paper should provide both an understanding of and an incentive for those with an interest in database use and the development of outcome-based projects.

Databases as Topic↗

PubMedDate not supplied

Math learning disorder: incidence in a population-based birth cohort, 1976-82, Rochester, Minn.

OBJECTIVE: To report the incidence of math learning disorder (Math LD) among school-aged children, overall and by gender. To compare incidence estimates obtained by using three different methods to identify Math LD cases. To assess the extent to which children manifest Math LD alone, versus Math LD with comorbid reading disorder. METHODS: This is a population-based, retrospective, birth cohort study. Subjects included all children born 1976-82 who remained in Rochester, Minn after age 5 (N = 5718). Using records from all public and private schools, medical facilities, and private tutorial services, all individually administered intelligence quotient and achievement tests and extensive medical, educational, and socioeconomic information were abstracted. Math LD was established using research criteria based on 3 formulas (regression-based discrepancy, nonregression-based discrepancy, low achievement). RESULTS: Cumulative incidence rates of Math LD by age 19 years varied from 5.9% to 13.8% according to the formula used. Boys were more likely to be affected than girls, with relative risk ratios from 1.6 to 2.2 depending on the formula applied. Many children with Math LD (35% to 56.7%, depending on the formula used to define Math LD) did not have a comorbid reading disorder. CONCLUSIONS: These results, from a community-based birth cohort, suggest that Math LD is common among schoolchildren, and is significantly more frequent among boys than girls, regardless of definition. Many children with Math LD do not have an associated reading disorder.

Adolescent↗

PubMedDate not supplied

Tinnitus impact: three different measurement tools.

The impact of tinnitus and overall levels of distress were measured with three assessment tools for patients with tinnitus. The Tinnitus Handicap Inventory (THI), the Symptom Checklist-90-Revised (SCL-90-R) and an activities limitations questionnaire were administered to 53 audiology patients reporting tinnitus. Forty-three percent of these patients experienced either quality of life reductions associated with tinnitus, substantial perceived handicap, and/or a high level of distress. Results from the General Severity Index (GSI) of the SCL-90-R indicated that 25% of these patients displayed distress greater than that of the general medical population. The SCL-90-R can be a useful tool for audiologists working with tinnitus patients in assessing needs for referral for psychological or psychiatric counseling.

Activities of Daily Living↗

PubMedDate not supplied

Influence of platelet-rich plasma added to xenogeneic bone grafts on bone mineral density associated with dental implants.

PURPOSE: The purpose of this study was to assess the bone mineral density changes after bone regeneration therapy using xenogeneic demineralized freeze-dried bone graft (DFDBG) plus platelet-rich plasma (PRP) and DFDBG alone in 3-wall peri-implant defects in dogs. MATERIALS AND METHODS: The mandibular premolars and molars of 9 adult hound dogs were removed surgically, and 90 sites were prepared for implant placement. Before implant placement, a total of 162 mesial and distal 3-wall peri-implant defects were surgically created. Defects were randomly assigned to three groups: DFDBG + PRP, DFDBG alone, and no treatment. Animals were sacrificed at 1, 2, and 3 months, and specimens were subjected to bone mineral density (BMD) and bone mineral content (BMC) analysis with a peripheral dual x-ray absorptiometry densitometer. RESULTS: The effect of treatment on BMD and BMC differed significantly by month of sacrifice (P = .030 and P = .035 for the month-by-treatment interactions, respectively). BMD differed significantly between peri-implant defects treated with DFDBG alone and untreated defects at 3 months (mean BMD of 0.6667 for DFDBG alone versus 0.5606 for untreated defects; P < .001). BMC also differed significantly between peri-implant defects treated with DFDBG alone and untreated defects at 3 months (mean BMC of 0.0276 for DFDBG alone versus 0.0236 for untreated defects; P = .001). No other pairwise comparison of the treatments within each month of sacrifice or at the overall treatment effect across all three months demonstrated significant differences. DISCUSSION: PRP has been proposed as an autogenous source of growth factors, which may increase the speed and completeness of healing. This study did not demonstrate a significant improvement in BMD or BMC when PRP was combined with DFDBG. Defects where grafting material was used, either with or without PRP, did demonstrate slightly greater BMD and BMC than those left untreated. CONCLUSION: This study found that the addition of PRP to xenogeneic bone grafts did not significantly alter BMD or graft maturity levels in this animal model.

Absorptiometry, Photon↗