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Biomedical subjects

A Nelson

Publications and source records attributed to A Nelson.

At least 55 records · Page 3Linked to original sources
PubMed1999

The health and economic benefits associated with pneumococcal vaccination of elderly persons with chronic lung disease.

BACKGROUND: More than 50% of the elderly population has not received pneumococcal vaccination. Uncertainty regarding the benefits of immunization, particularly for noninvasive disease, may contribute to the underuse of pneumococcal vaccine. OBJECTIVE: To assess the health and economic benefits associated with pneumococcal vaccination. METHODS: We conducted a 2-year retrospective cohort study among all elderly members of a staff-model managed care organization who had a baseline diagnosis of chronic lung disease. The study outcomes were assessed over 2 years, from November 15, 1993, through November 14, 1995, and included hospitalizations for pneumonia and influenza, death, and hospitalization costs. Using administrative data, we compared these outcomes for vaccinated and unvaccinated subjects using multivariate models to control for subjects' baseline demographic and health characteristics. The additive benefits of combined influenza and pneumococcal vaccination were also assessed for the 2 influenza seasons included in the study. RESULTS: There were 1898 subjects. Pneumococcal vaccination was associated with significantly lower risks for pneumonia hospitalizations (adjusted risk ratio [RR], 0.57; 95% confidence interval [CI], 0.38-0.84; P=.005) and for death (adjusted RR, 0.71; 95% CI, 0.56-0.91; P = .008). For the control outcome of all nonpneumonia hospitalizations, rates did not differ significantly between the 2 groups (adjusted RR, 0.91; 95% CI, 0.77-1.07; P= .24). During the influenza seasons included in the study, the benefits of pneumococcal and influenza vaccinations were additive, with an adjusted RR of 0.28 (95% CI, 0.14-0.58; P<.001) for the number of hospitalizations for pneumonia and influenza among persons who had received both vaccinations compared with those who had received neither and an adjusted odds ratio of 0.18 (95% CI, 0.11-0.31; P<.001) for death. Over the 2-year outcome period, pneumococcal vaccination was also associated with direct medical care cost savings. CONCLUSIONS: Pneumococcal vaccination of elderly persons with chronic lung disease was associated with fewer hospitalizations for pneumonia, fewer deaths, and direct medical care cost savings.

Aged↗
PubMed1999

Relation between influenza vaccination and outpatient visits, hospitalization, and mortality in elderly persons with chronic lung disease.

BACKGROUND: Influenza vaccine is underused in groups targeted for vaccination. OBJECTIVE: To define the effects of influenza and the benefits of influenza vaccination in elderly persons with chronic lung disease. DESIGN: Retrospective, multiseason cohort study. SETTING: Large managed care organization. PATIENTS: All elderly members of a managed care organization who had a previous diagnosis of chronic lung disease. MEASUREMENTS: Outcomes in vaccinated and unvaccinated persons for the 1993-1994, 1994-1995, and 1995-1996 influenza seasons were compared after adjustment for baseline demographic and health characteristics. All data were obtained from administrative databases. RESULTS: Vaccination rates were greater than 70% for each season. Among unvaccinated persons, hospitalization rates for pneumonia and influenza were twice as high in the influenza seasons as they were in the interim (noninfluenza) periods. Influenza vaccination was associated with fewer hospitalizations for pneumonia and influenza (adjusted risk ratio, 0.48 [95% CI, 0.28 to 0.82]) and with lower risk for death (adjusted odds ratio, 0.30 [CI, 0.21 to 0.43]) during the influenza seasons. It was also associated with fewer outpatient visits for pneumonia and influenza and for all respiratory conditions. CONCLUSIONS: For elderly persons with chronic lung disease, influenza is associated with significant adverse health effects and influenza vaccination is associated with substantial health benefits, including fewer outpatient visits, fewer hospitalizations, and fewer deaths. Health care providers should take advantage of all opportunities to immunize these high-risk patients.

Age Factors↗
PubMed1999

Validation of self-report of influenza and pneumococcal vaccination status in elderly outpatients.

OBJECTIVE: To assess the validity of self-reported influenza and pneumococcal vaccination status. DESIGN: Cross-sectional surveys of outpatients aged 65 years or older. SETTING: A Veterans Affairs Medical Center (VA) and a community managed care organization (MCO). Both organizations have organized influenza and pneumococcal vaccination programs. SUBJECTS: VA subjects included all elderly respondents to a mailed survey of 500 randomly selected outpatients. MCO subjects included all respondents to a telephone survey of 300 randomly selected elderly members of the MCO. MEASUREMENTS: The VA survey was conducted following the 1995-1996 influenza season while the MCO survey was conducted following the 1994-1995 season. Self-report from the mailed survey for VA subjects and from the telephone survey for MCO subjects was compared to medical record documentation (paper and computerized combined). RESULTS: The response rate was 77% (n = 369) for the VA subjects of whom 195 (53%) were aged 65 or older. The response rate for the MCO subjects was 84% (n = 237). Self-report of influenza vaccination had a sensitivity (SENS) of 1.0 and a specificity (SPEC) of .79 with a kappa of .72 (95% CI .58-.86) among VA patients. Among MCO patients, self-report of influenza vaccination had a SENS of .98 and a SPEC of .71 with kappa of .75 (95% CI .69-.89). Self-report of pneumococcal vaccination status among VA patients had a SENS of .97 and a SPEC of .53 with a kappa of .42 (95% CI .32-.52). Among MCO patients, self-report of pneumococcal vaccination had a SENS of .90 and a SPEC of .64 with a kappa of .54 (95% CI .40-.68). A secondary analysis excluding subjects living outside of the VA's catchment area improved the specificity and indices of concordance of self-report of both influenza and pneumococcal vaccination. A secondary analysis of MCO data which excluded subjects who received a pneumococcal vaccination > 2 years prior to the study also improved concordance and the negative predictive value of self-report. CONCLUSIONS: Self-report of influenza vaccination is a highly sensitive and moderately specific measure. Self-report of pneumococcal vaccination is also a highly sensitive but less specific measure of vaccination status. Lower rates of validity for pneumococcal vaccination may reflect both less accurate recall, particularly for more distant vaccination, and less complete documentation in medical records.

Aged↗
PubMed1999

Kaposi's sarcoma in women: A clinicopathologic study.

BACKGROUND: Although all epidemiologic subsets of Kaposi's sarcoma (KS) (i.e., sporadic, endemic, epidemic, and iatrogenic) have an association with human herpes virus 8 (HHV8), these subsets occur in patient populations with distinctive clinical features. To a variable degree men outnumber women in all subsets. OBJECTIVE: A retrospective study of women with histologically proven cutaneous KS was undertaken to determine the clinical and histopathologic features, as well as any associations. METHODS: Two hundred and fifty cases of cutaneous KS in women from 1975 to 1993 were reviewed. RESULTS: Of the patients, 80% were more than 60 years of age, and of the patients less than 60 years old, 28 were from areas of the world with endemic KS. All HIV+ patients but one were from areas of endemic KS. Two patients were renal transplant patients. Sixty-four percent of the patients had single lesions and 21% recurrent lesions. Twelve patients had, or were known to develop, internal involvement, and in six patients the cause of death was KS. All but four cases histologically showed areas of solid proliferations of tumour cells consistent with plaque or tumour stage. An angiosarcoma-like histologic pattern appeared to be associated with more aggressive epidemiologic subsets. High mitotic rates were rarely seen and did not correlate with aggressive epidemiologic subsets. CONCLUSION: Kaposi's sarcoma in women is diagnosed almost exclusively in plaque or tumour stage. The majority of women within our study fit within the epidemiologic subset of sporadic KS.

Adult↗
PubMed1999

A two-year study of microscopic urinalysis competency using the urinalysis-review computer program.

BACKGROUND: The microscopic examination of urine sediment is one of the most commonly performed microscope-based laboratory tests, but despite its widespread use, there has been no detailed study of the competency of medical technologists in performing this test. One reason for this is the lack of an effective competency assessment tool that can be applied uniformly across an institution. METHODS: This study describes the development and implementation of a computer program, Urinalysis-ReviewTM, which periodically tests competency in microscopic urinalysis and then summarizes individual and group test results. In this study, eight Urinalysis-Review exams were administered over 2 years to medical technologists (mean, 58 technologists per exam; range, 44-77) at our academic medical center. The eight exams contained 80 test questions, consisting of 72 structure identification questions and 8 quantification questions. The 72 structure questions required the identification of 134 urine sediment structures consisting of 63 examples of cells, 25 of casts, 18 of normal crystals, 8 of abnormal crystals, and 20 of organisms or artifacts. RESULTS: Overall, the medical technologists correctly identified 84% of cells, 72% of casts, 79% of normal crystals, 65% of abnormal crystals, and 81% of organisms and artifacts, and correctly answered 89% of the quantification questions. The results are probably a slight underestimate of competency because the images were analyzed without the knowledge of urine chemistry results. CONCLUSIONS: The study shows the feasibility of using a computer program for competency assessment in the clinical laboratory. In addition, the study establishes baseline measurements of competency that other laboratories can use for comparison, and which we will use in future studies that measure the effect of continuing education efforts in microscopic urinalysis.

Educational Measurement↗
PubMed1998

Cathepsin L: critical role in Ii degradation and CD4 T cell selection in the thymus.

Degradation of invariant chain (Ii) is a critical step in major histocompatibility complex class II-restricted antigen presentation. Cathepsin L was found to be necessary for Ii degradation in cortical thymic epithelial cells (cTECs), but not in bone marrow (BM)-derived antigen-presenting cells (APCs). Consequently, positive selection of CD4+ T cells was reduced. Because different cysteine proteinases are responsible for specific Ii degradation steps in cTECs and BM-derived APCs, the proteolytic environment in cells mediating positive and negative selection may be distinct. The identification of a protease involved in class II presentation in a tissue-specific manner suggests a potential means of manipulating CD4+ T cell responsiveness in vivo.

Animals↗
PubMed1998

Randomised controlled trial of prophylactic antibiotics before insertion of intrauterine devices. IUD Study Group.

BACKGROUND: The value of antibiotic prophylaxis before insertion of an intrauterine device (IUD) remains uncertain. We undertook a triple-masked, randomised, placebo-controlled trial to find out whether such prophylaxis reduces the rate of IUD removal within 90 days. METHODS: 11 clinic sites in southern California enrolled women who requested IUD insertion and were at low risk of sexually transmitted infection according to self-reported medical history. We randomly assigned 1985 participants either 500 mg azithromycin or placebo capsules of identical appearance taken about 1 h before insertion of a Copper T 380A IUD. 118 women did not have an IUD inserted. We followed up 1833 of the remaining 1867 (98%) participants for at least 90 days after insertion. FINDINGS: The rate of IUD removal for any reason other than partial expulsion was 3.8% (35/918) in the antibiotic group and 3.4% (31/915) in the placebo group (relative risk 1.1 [95% CI 0.7-1.8]). The two treatment groups sought medical attention with equal frequency (mean 38 visits per 100 women). During the 90 days after IUD insertion, only one woman from each assignment group had salpingitis, as defined by established criteria. INTERPRETATION: Prophylaxis with azithromycin did not affect the likelihood that a woman would retain her IUD at 90 days or the frequency of postinsertion medical attention. In appropriately screened women, the risk of upper-genital-tract infection is negligible after IUD insertion, with or without the administration of prophylactic antibiotics.

Adult↗
PubMed1998

The role of peptides in thymic positive selection of class II major histocompatibility complex-restricted T cells.

A thymic epithelial cell line transfected with I-Ek was used in reaggregate cultures to study the role of peptides in positive selection of T cell receptor transgenic thymocytes. In this system, positive selection of CD4 SP cells occurred only after the addition of exogenous peptide. Analysis of antigen analogs indicated an inverse relationship between the antigenicity for peripheral T cells and the concentration of peptide required for positive selection. These data are most consistent with an avidity (rather than an affinity) model of positive selection, in which ligand density and the affinity of T cell receptor act in concert to determine the fate of developing thymocytes.

Amino Acid Sequence↗
PubMed1998

Much ado about not...enough data: high-dose chemotherapy with autologous stem cell rescue for breast cancer.

High-dose chemotherapy with autologous bone marrow or stem cell rescue (HDC/ASCR) has been proposed as a promising treatment strategy for breast cancer. Despite the frequency with which this procedure is performed, the role of HDC/ASCR in the treatment of breast cancer remains undefined. The purpose of this review is to examine the rationale for the procedure, the research progress to date, and the limitations of available data. A literature search of Medline from January 1966 through May 1997, CancerLit from January 1983 through May 1997, and Current Contents through May 1997 identified more than 600 English language papers or abstracts on this topic. Our review focuses on the preclinical and clinical data that explore the concept of chemotherapy dose intensity and the role of dose intensity in treating breast cancer. HDC/ASCR is based on the hypothesis that high-dose chemotherapy will overcome drug resistance, eradicate metastatic disease, and increase the proportion of women with breast cancer who are "cured." To date, results from only one phase 3 trial of HDC/ASCR compared with more conventional therapy have been published. Phase 2 and some phase 3 data on HDC/ASCR in the treatment of high-risk primary breast cancer and metastatic breast cancer are discussed. However, the results are inconclusive. The completion of national and international randomized trials is urgently needed to establish definitively the role of HDC/ASCR in the treatment of breast cancer.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1998

Intracerebroventricular administration of leptin markedly enhances insulin sensitivity and systemic glucose utilization in conscious rats.

This study examines the acute, subacute (overnight), and chronic (7-day) effects of intracerebroventricular (i.c.v.) administration of r-metMuLeptin on insulin sensitivity and systemic glucose turnover in conscious unrestrained rats (body weight, 250 to 300 g). Under postabsorptive conditions, acute i.c.v. leptin ([AL] 10 microg bolus) did not affect tracer (3-(3)H-glucose)-determined glucose production (GP) and utilization (GU) rates during the 2-hour hyperinsulinemic (2 mU x kg(-1) x min(-1)) euglycemic clamp. Chronic i.c.v. leptin ([CL] 10 microg/d for 7 days) administered by osmotic pumps markedly reduced the daily food consumption (P < .05), body weight (P < .05), and postabsorptive basal plasma glucose level (P < .01). During the glucose clamp, GP was markedly suppressed (55%) with CL (P < .001 v vehicle and pair-fed control groups). The insulin-induced increment in GU was significantly greater with CL (23.3 +/- 1.8 mg(-1) x kg(-1) x min(-1)) than with vehicle (16.9 +/- 0.2) and pair-feeding (17.1 +/- 0.6, both P < .001). Subacute i.c.v. leptin ([SL] 10 microg bolus) moderately but insignificantly decreased overnight food consumption (-18%) and body weight (-2.5 +/- 1.5 g). The glucose infusion rate during the final 60 minutes of the glucose clamp was 43% greater than for the vehicle group (P < .0001). SL also significantly increased GU (P < .005) and suppressed GP (P < .05) during the glucose clamp. Thus, we conclude that i.c.v. administered leptin has strong actions on the central nervous system that result in significant increases in insulin sensitivity and systemic GU, and these effects are achieved as early as overnight after leptin administration.

Animals↗
PubMed1998

Is CD30 (Ki-1) immunostaining in cutaneous eruptions useful as a marker of Th1 to Th2 cytokine switching and/or as a marker of advanced HIV-1 disease?

CD30 is a member of the tumour necrosis factor/nerve growth factor receptor superfamily, which is expressed on CD4+ and CD8+ T-cell clones which produce T helper (Th) 2-type cytokines. It has been proposed that disease progression in HIV-1 is associated with Th1 to Th2 cytokine switching. In 70 cutaneous biopsies from HIV-1 positive patients in different stages of disease, we performed a battery of immunohistochemical stains. These included antibodies to CD3, UCHL-1, OPD-4, L-26, KP-1 and CD30 (Ki-1). In addition, we used a similar battery of stains on cutaneous biopsies of HIV-1 negative patients with inflammatory dermatoses which are established as Th1 or Th2 dominant, e.g. polar leprosy. CD30+ cells were rarely present in early stages of HIV-1 disease, but commonly present in later stages of disease. However, there were cases of late HIV-1 disease which did not contain CD30+ cells. Increased numbers of CD30+ cells were more commonly seen in later stages of HIV-1 disease. However, the expression of CD30 appeared to be better in predicting other established Th2 cutaneous infiltrates in HIV-1 negative patients than in predicting a Th2 cutaneous cytokine pattern in advanced HIV-1 disease.

Biomarkers↗
PubMed1998

Lead levels in high-risk and low-risk young children in the Minneapolis-St Paul metropolitan area.

OBJECTIVES: To determine distribution of lead levels among children in a low-risk area; to validate a prescreening questionnaire; and to determine if universal lead screening is necessary in children in this area. DESIGN: Blood lead levels and questionnaires were obtained on eligible patients. Data were analyzed using stepwise regression analysis. SETTING: Community clinics and a health maintenance organization (HMO) in the Minneapolis-St Paul metropolitan area. PATIENTS: A total of 9603 children at well-child visits, age 6 months to 6 years at community clinics, and 6 months to 3 years at the HMO. OUTCOME MEASURES: Whole blood lead levels (WBLs) and questionnaires. RESULTS: The total sample rate of WBLs at >/=10 microg/dL was 12%, at >/=15 microg/dL was 31/2%, and at >/=20 microg/dL was 1.2%. At both 10 microg/dL and 15 microg/dL, the non-HMO group was at higher risk. For both groups, risk factors included living in the central cities, and living in housing built before 1950. For the non-HMO group a history of the child eating paint chips, or the child or a sibling having previous lead poisoning were also risk factors. CONCLUSIONS: Not all children need lead screening. Children living in the central cities, or with the risk factors of living in housing built before 1950 or a previous history of lead poisoning should be screened.

Child↗