胰岛素样生长因子-I和人绒毛膜促性腺激素对成年大鼠Leydig细胞葡萄糖转运蛋白基因表达调控

目的:研究胰岛素样生长因子I(IGF I)和人绒毛膜促性腺激素(hCG)对成年大鼠睾丸Leydig细胞中葡萄糖转运蛋白(GLUT)基因表达的影响,为进一步探讨Leydig细胞中睾酮的合成、分泌与葡萄糖代谢的关系提供依据。方法:采用改良的Klinefelter方法从成年大鼠睾丸中分离获得Leydig细胞;用反转录聚合酶链技术检测IGF I和hCG对原代培养的Leydig细胞中GLUT基因表达的调控作用。结果:分离得到纯度为98%的大鼠Leydig细胞,并与对照组比较,hCG可显著增加Leydig细胞中GLUT8基因mRNA的表达水平(P<0.001),且此作用具有剂量依赖性与时效性。当在试验组细胞中单独加入IGF I或IGF I和hCG作用于细胞后,发现IGF I(100ng mL)可显著增加Leydig细胞中GLUT8基因mRNA的表达(P<0.01),也可与hCG协同作用显著提高GLUT8基因的mRNA表达,该结果与IGF I(100ng mL)和hCG(10ng mL)能协同作用极显著增加睾酮合成水平(P<0.001)的结果是相吻合的。在大鼠Leydig细胞中,无论10ng mL或100ng mL还是两者同时作用于细胞,都不能影响GLUT1和GLUT3基因的mRNA水平。结论:在成年大鼠Leydig细胞中,IGF I和hCG对细胞中的GLUT8基因表达的调节作用具有特异性,其协同作用能显著提高细胞中GLUT8基因mRNA水平,增强细胞摄取葡萄糖的能力,给细胞提供更多的代谢能源,最终增加Leydig细胞睾酮的合成与分泌。     

The performance of administrative and self-reported measures for risk adjustment of Veterans Affairs expenditures

OBJECTIVE: To evaluate the performance of different prospective risk adjustment models of outpatient, inpatient, and total expenditures of veterans who regularly use Veterans Affairs (VA) primary care. DATA SOURCES: We utilized administrative, survey and expenditure data on 14,449 VA patients enrolled in a randomized trial that gave providers regular patient health assessments. STUDY DESIGN: This cohort study compared five administrative data-based, two self-report risk adjusters, and base year expenditures in prospective models. DATA EXTRACTION METHODS: VA outpatient care and nonacute inpatient care expenditures were based on unit expenditures and utilization, while VA expenditures for acute inpatient care were calculated from a Medicare-based inpatient cost function. Risk adjusters for this sample were constructed from diagnosis, medication and self-report data collected during a clinical trial. Model performance was compared using adjusted R2 and predictive ratios. PRINCIPAL FINDINGS: In all expenditure models, administrative-based measures performed better than self-reported measures, which performed better than age and gender. The Diagnosis Cost Groups (DCG) model explained total expenditure variation (R2=7.2 percent) better than other models. Prior outpatient expenditures predicted outpatient expenditures best by far (R2=42 percent). Models with multiple measures improved overall prediction, reduced over-prediction of low expenditure quintiles, and reduced under-prediction in the highest quintile of expenditures. CONCLUSIONS: Prediction of VA total expenditures was poor because expenditure variation reflected utilization variation, but not patient severity. Base year expenditures were the best predictor of outpatient expenditures and nearly the best for total expenditures. Models that combined two or more risk adjusters predicted expenditures better than single-measure models, but are more difficult and expensive to apply.     

CDR3 spectratyping identifies clonal expansion within T-cell subpopulations that demonstrate therapeutic antitumor activity

BACKGROUND: Antigen-specific T cells undergoing clonal expansion share common rearrangements of the variable complementary determining region 3 (CDR3) of the T-cell receptor (TCR), which can be identified using polymerase chain reaction-based V beta (VB) spectratyping. The purpose of this study was to determine whether CDR3 spectratyping identifies clonal expansion within tumor-draining lymph node (TDLN) subpopulations with antitumor therapeutic activity. METHODS: Recently sensitized T cells from 4T1 murine mammary carcinoma TDLN were fractionated based on CD62L (L-selectin) surface expression before RNA isolation and culture. L-selectinlow and L-selectinhigh TDLN were analyzed for T-cell receptor usage by immunophenotyping and CDR3 spectratyping, and then culture activated with anti-CD3/IL-2 to assess therapeutic efficacy after adoptive transfer. RESULTS: Adoptive transfer experiments confirmed that mice treated with culture-activated L-selectinlow TDLN cells exhibited delayed subcutaneous tumor growth and prolonged survival as compared to control or L-selectinhigh-treated mice (P < .01). CDR3 spectratyping demonstrated oligoclonal skewing of the CDR3 regions within several VB families including VB3, VB5.2, and VB17 in L-selectinlow but not in L-selectinhigh TDLN. Although fluorescence-activated cell sorter analysis demonstrated the highest percentage of cells expressing VB13 usage in both populations, CDR3 spectratyping did not identify the presence of clonal expansion. CONCLUSIONS: These data suggest that CDR3 spectratyping may be useful in identifying T cells undergoing clonal expansion that demonstrate antitumor therapeutic activity.     

Evolution of clonal cytogenetic abnormalities in aplastic anemia

Prior to the introduction of effective therapies, the high mortality rates of severe aplastic anemia (AA) precluded recognition of late complications of this disease. Once the survival of AA improved, observation of clonal evolution raised questions as to whether the development of secondary myelodysplastic syndrome (MDS) is a part of the extended natural history of the disease or is related to the therapies applied. Clinical features of myelodysplasia and AA can overlap, and typical MDS may evolve as a complication of AA. Common pathophysiologic elements operate in these diseases and are subject to many studies and theories as to what mechanisms in AA may lead to the late evolution of MDS. Similarly, AA has been hypothesized to be a reflection of an over-reactive immune response triggered by the appearance of genetically altered and/or phenotypically abnormal dysplastic clones. Hypocellular variants of myelodysplasia and responsiveness of certain forms of MDS to immunosuppressive regimens serve as the most appealing examples of the intricate and close pathophysiologic relationship of this disease with AA. The diagnosis of clonal evolution in the course of AA can be obvious if secondary cytopenia involves hypercellularity and a high percentage of blasts. In addition, the occurrence of a new karyotypic defect objectively heralds the progression of disease to MDS. However, the diagnostic imprecision of dysplasia recognition in the context of marrow hypocellularity, inability to obtain informative cytogenetics, and a high proportion of MDS cases with normal karyoptype have hampered studies designed to determine the frequency and timing of MDS evolution in AA. In addition, the diagnostic criteria and definitions used are not unified. While some centers recognize that the abnormal karyotype does not preclude the diagnosis of AA; in others, the diagnosis of AA includes the presence of normal karyoptype. Many typical features of dysplastic evolution in AA have been clarified. For example, karyotypes most frequently encountered in MDS secondary to AA involve chromosomes 6, 7 and 8. The evolution rates seem to be in the range of 10 - 15% in 10 years, but there are no predictive clues as to which patients are at greatest risk for this complication. Study of the mechanisms of clonal evolution in AA may help understand the pathophysiology of other forms of MDS and leukemia and also the mechanisms of antileukemic surveillance. Clinically, identification of patients at increased risk for clonal complications may influence the choice of therapies applied.     

VA community-based outpatient clinics: cost performance measures

OBJECTIVE: To examine the direct costs of treating veterans in Community-Based Outpatient Clinics (CBOC) and primary care clinics operated by VA medical centers (VAMCs) between April 1998 and September 1998. RESEARCH DESIGN: In a retrospective observational study of patients in eighteen CBOCs and fourteen VAMCs, direct costs were compared. In addition, the costs of treating patients in new and established CBOCs were also examined. MEASURES: The three types of costs examined include direct cost per primary care visit, direct primary care cost per patient, and total direct cost per patient in ordinary least squares regressions with facility-specific random effects. Indirect costs for overhead and administration were excluded. All cost comparisons controlled for patient characteristics and case-mix differences via the Diagnostic Cost Group methodology. RESULTS: Results indicate that CBOC patients and VAMC patients had similar direct primary care costs on a per visit and per patient basis. Total direct costs for CBOC patients were lower compared with VAMC patients, because of lower specialty and ancillary care costs. Patients in new CBOCs had similar primary, specialty, ancillary and inpatient care costs when compared with patients in established CBOCs. CONCLUSION: Lower total costs for CBOC patients may be a consequence of substituting primary care at CBOCs for expensive specialty and ancillary care at VAMCs. CBOCs may be an alternative approach to providing care to veterans at a lower cost than traditional delivery models based in VA Medical Centers.