Hardy-Weinberg testing for continuous data

Estimation of allelic and genotypic distributions for continuous data using kernel density estimation is discussed and illustrated for some variable number of tandem repeat data. These kernel density estimates provide a useful representation of data when only some of the many variants at a locus are present in a sample. Two Hardy-Weinberg test procedures are introduced for continuous data: a continuous chi-square test with test statistic T(CCS) and a test based on Hellinger's distance with test statistic T(HD). Simulations are used to compare the powers of these tests to each other and to the powers of a test of intraclass correlation T(IC), as well as to the power of Fisher's exact test T(FET) applied to discretized data. Results indicate that the power of T(CCS) is better than that of T(HD), but neither is as powerful as T(FET). The intraclass correlation test does not perform as well as the other tests examined in this article.     

Cloning, expression, and localization of a novel gamma-adaptin-like molecule

We describe the cloning, expression, and localization of gamma2-adaptin, a novel isoform of gamma-adaptin. The predicted human and mouse gamma2-adaptin proteins are approximately 90 kDa and 64.4% and 61.7%) identical to gamma-adaptin, respectively. gamma2-Adaptin was localized to the Golgi, its localization distinct from gamma-adaptin. The membrane association of gamma- and gamma2-adaptin could further be distinguished by differential sensitivity to the fungal metabolite brefeldin A, gamma2-adaptin binding being insensitive to drug treatment. Together, these results suggest that gamma2-adaptin plays a role in membrane transport distinct from that played by gamma-adaptin.     

Fever-range hyperthermia enhances L-selectin-dependent adhesion of lymphocytes to vascular endothelium

The L-selectin leukocyte adhesion molecule plays an important role in controlling leukocyte extravasation in peripheral lymph nodes and at sites of tissue injury or infection. Although febrile responses during infection and inflammation are associated with enhanced immune activity, the contribution of fever-range temperatures to controlling lymphocyte recruitment to tissues has not been previously examined. In this report we provide evidence that direct exposure of lymphocytes to fever-range temperatures (38-41 degrees C) in vitro for 9 to 24 h resulted in a >100% increase in L-selectin-dependent adhesion of these cells to lymph node high endothelial venules (HEV). Moreover, culture of lymphocytes under hyperthermia conditions markedly enhanced the ability of these cells to traffic in an L-selectin-dependent manner to peripheral lymph nodes, mesenteric lymph nodes, and Peyer's patches. In contrast, febrile temperatures did not increase LFA-1 function as assessed by measuring lymphocyte adhesion to ICAM-1-3T3 transfectants. Fever-range hyperthermia further did not increase L-selectin surface density on lymphocytes or L-selectin-dependent recognition of soluble carbohydrate substrates; however, a marked increase in ultrastructural immunogold-labeling of L-selectin was observed in response to thermal stimuli. These results suggest that elevated temperatures enhance L-selectin adhesion and/or avidity through the regulation of L-selectin conformation or organization in the plasma membrane. Finally, the observed thermal effects on L-selectin adhesion were attributed to soluble factors in the conditioned medium of heat-treated cells. Taken together, these data provide new insight into the potential physiologic role of the febrile response in enhancing lymphocyte recruitment to tissues through the regulation of L-selectin adhesion.     

Major histocompatibility complex class II-dependent antigen presentation by human intestinal endothelial cells

BACKGROUND & AIMS: In the normal gut, human intestinal microvascular endothelial cells (HIMECs) express major histocompatibility complex (MHC) class II molecules. Enhanced expression is found in chronic inflammation. We examined the cytokine regulation of MHC class II molecules and the associated invariant chain (Ii) in HIMECs and investigated whether such cells can process and present a complex protein antigen to T cells. METHODS: Enzyme-linked immunosorbent assay, flow cytometry, immunoelectron microscopy, as well as T-cell activation assay with HIMECs and HLA-DR-restricted T-cell clones were employed. RESULTS: In unstimulated HIMEC monolayers, HLA-DR, -DP, and -DQ and Ii were undetectable at the protein level, but interferon gamma (IFN-gamma) (100 U/mL) induced expression that peaked for DR after 2-3 days, for DP after 4-6 days, for DQ after 10-12 days, and for Ii after 2-3 days. Tumor necrosis factor alpha had no effect alone but enhanced class II expression in combination with IFN-gamma, most notably for DQ and DP. HLA-DR3-restricted and Mycobacterium tuberculosis heat shock 65-kilodalton-specific T-cell clones were activated to produce IFN-gamma in response to relevant antigen presented by IFN-gamma-treated HIMECs. This response was inhibited by blocking monoclonal antibody to HLA-DR and by chloroquine when compared to professional antigen-presenting cells, HIMECs activated T-cell clones quite efficiently. CONCLUSIONS: These data suggest that microvascular endothelial cells can present complex protein antigens in the human gut.     

Differential chemotactic behavior of developing T cells in response to thymic chemokines

Differentiation-dependent thymocyte migration in the thymus may be important for T lymphopoiesis and might be regulated by thymic chemoattractants. We examined modulation of chemotactic responsiveness of thymocyte subsets during their early to late stages of development in response to 2 thymus-expressed chemokines, SDF-1 and CKbeta-11/MIP-3beta/ELC. SDF-1 shows chemotactic preference for immature thymocytes (subsets of triple negative thymocytes and double positive [DP] subset) over mature single positive (SP) thymocytes. CKbeta-11/MIP-3beta/ELC shows low chemotactic activity on the immature thymocytes, but it strongly attracts mature SP thymocytes, effects opposite to that of SDF-1. SDF-1-dependent chemoattraction of immature thymocytes is not significantly desensitized by a negative concentration gradient of CKbeta-11/MIP-3beta/ELC, and chemoattraction of mature SP thymocytes to CKbeta-11/MIP-3beta/ELC is not antagonized by SDF-1, demonstrating that these two chemokines have different chemoattractant preferences for thymocyte subsets and would probably not inhibit each other's chemotaxis in the event of microenvironmental coexpression. The chemotactic responsiveness of thymocytes and mature T cells to the 2 chemokines is respectively enhanced after selection process and migration to the spleen. These studies demonstrate the presence of thymocyte chemoattractants with differential chemotactic preference for thymocytes, a possible mechanism for thymocyte migration in the thymus.     

Combined therapeutic efficacy of the thymidylate synthase inhibitor ZD1694 (Tomudex) and the immunotoxin B43(anti-CD19)-PAP in a SCID mouse model of human B-lineage acute lymphoblastic leukemia

The quinazoline antifolate N-(5-[N-(3,4-dihydro-2-methyl-4-oxoquinazolin-6-ylmethyl)-N- methylamino]-2-thenoyl)-L-glutamic acid (ZD1694; Tomudex) is a potent inhibitor of thymidylate synthase and causes cell death through disruption of DNA synthesis and repair by blocking the obligatory thymidine nucleotide synthesis. B43(anti-CD19)-PAP immunotoxin is a potent inhibitor of protein synthesis in CD19+ B-lineage acute lymphoblastic leukemia (ALL) cells and causes apoptosis. In this model, 100% of SCID mice challenged with 1 x 10(6) human NALM-6 B-lineage ALL cells develop overt and invariably fatal leukemia. All of the 22 control SCID mice treated with phosphate-buffered saline died of disseminated human leukemia between 31 and 61 days with a median survival of 41.2 days. Treatment with ZD 1694 resulted in improved leukemia-free survival with a median survival of 69.2 days (P < 0.001, log-rank test). B43-PAP treatment was more effective than ZD1694 (P=0.026) and resulted in 51.0% long-term leukemia-free survival with a median survival of 187.5 days (P < 0.0001. log-rank test). The combination of ZD1694 and B43-PAP was more effective than either agent alone and resulted in 100% long-term leukemia-free survival. To our knowledge, this preclinical study is the first to demonstrate the feasibility and therapeutic advantage of combining an anti-leukemia immunotoxin with a thymidylate synthase inhibitor.     

Contrasting factors associated with abdominal and peripheral weight gain among adult women

OBJECTIVE: To identify contrasts between the risk factors associated with abdominal weight gain and those associated with peripheral weight gain. DESIGN: Prospective mail survey. SUBJECTS: 44080 white, non-Hispanic, healthy women who were questioned in 1982 (baseline age 40-54 y) and 1992 about weight, diet, alcohol use, smoking, 10 physical activities and other variables. MEASUREMENTS: Self reports in 1992 identified 4261 women who gained weight in the abdomen and 7440 women who gained in the periphery (sites other than the abdomen). Using identical logistic models adjusted for age, baseline body mass index (BMI) and numerous covariates, the abdominal-gain group and the peripheral-gain group were separately compared with 10,888 women who did not gain weight. RESULTS: The likelihood of abdominal gain exceeded that of peripheral gain (by comparison of estimated odds ratios, abdominal vs peripheral) for high meat eaters (1.50 vs 1.15), frequent users of liquor (1.09 vs 0.54), moderate cigarette smokers (0.86 vs 0.59), heavy cigarette smokers (0.96 vs 0.36), cigarette quitters (2.13 vs 1.63), women with high parity (1.52 vs 1.15) and those who reported major weight gain since age 18 y (1.22 vs 0.65). Abdominal gain was less likely than peripheral gain for high vegetable eaters (0.71 vs 0.91), women who exercised > or = 4 h/wk [(especially aerobics/ calisthenics (0.28 vs 0.91) or walking (0.84 vs 1.06)], women who completed menopause (0.74 vs 0.98) and consistent users of estrogen replacement therapy (0.93 vs 1.22). CONCLUSION: A behavior or characteristic may be associated differently with the risks of abdominal and peripheral weight gain. This insight could strengthen recommendations for preventing major chronic diseases.