Height, weight, and body mass index among Akwesasne Mohawk youth.

Information on the growth of contemporary Native American adolescents is limited. A few studies have shown that Native Americans have growth patterns that may differ from U.S. reference values. We describe basic anthropometric characteristics (height and weight) of Mohawk youth between the ages of 10.0 and 16.99 years from the Akwesasne Mohawk Nation. Body mass index (BMI) was calculated. Mean height of Akwesasne Mohawk youth approximates the 50th percentile of reference values as determined by the 2000 Center for Disease Control and Prevention (CDC) growth charts. At every age, weight means of males approximate or exceed the 90th percentile and all mean weights of females approximate the 85th percentile. Akwesasne males are significantly taller than females from age 14 on and significantly heavier at ages 14 and 16. All age-specific BMI means for males are at or above the 90th percentile and females' means are at or above the 85th. The potential for long-term health effects associated with being overweight has implications for the future health of young Native Americans.     

Use of alternative rules (other than the 1(2)s) for evaluating interlaboratory performance data

Previous studies have documented the ineffectiveness of using either the group mean +/- 2 group standard deviations (SD) or the 1(2)s rule as the standard of acceptable performance in evaluating interlaboratory proficiency testing (PT) data. Using computer simulation of PT data, we evaluated the efficiency of 244 alternatives to the 1(2)s rule, all based on the PT population's mean and SD. Using the traditional interlaboratory PT format, we determined the ability of each rule to correctly identify both good and deficient intralaboratory performance. The rules are based on results from one to five PT samples "analyzed" at the same time. Because the effectiveness of the criteria set for acceptable performance in a PT program is influenced by the population SD, each rule's capabilities were examined for PT populations with interlaboratory SDs ranging from 1% through 10% of the population mean value. All rules achieve their maximum efficiency over a narrow range of interlaboratory SDs. For PT evaluations of intralaboratory performance to be optimally effective, selection of the rule must be based on the SD of the PT population.     

Vertebral compression fracture as a presenting feature of acute lymphoblastic leukemia in children

Twenty-four (1.6%) of 1466 children with acute lymphoblastic leukemia (ALL) treated at St. Jude Children's Research Hospital had vertebral compression fractures at diagnosis. When compared with patients without this complication, they were more likely to have good prognostic features, including a leukocyte count of greater than 25 X 10(9)/l, a leukemic cell DNA index of greater than 1.15, and hyperdiploidy (greater than 50 chromosomes). Complete remission of ALL was induced in all patients, and symptoms of vertebral compression fractures abated following antileukemia therapy. Although the diagnosis of ALL was delayed for some patients because this unusual presenting complication was not recognized as such, their treatment outcome was as good as that for other children with "standard-risk" ALL.     

Comparison of modified Bordet-Gengou and modified Regan-Lowe media for the isolation of Bordetella pertussis and Bordetella parapertussis.

Culture and fluorescent-antibody methods for detection of Bordetella species were evaluated by two state public health laboratories. Field-inoculated plates of Regan-Lowe agar medium were most useful if incubation was initiated on the day of collection. Regan-Lowe and Bordet-Gengou media were comparable for subculturing nasopharyngeal specimens that were transported and enriched in half-strength Regan-Lowe agar. Maximum sensitivity was achieved when the media were used in parallel. Fluorescent-antibody-stained smears of nasopharyngeal specimens were more sensitive for detection of Bordetella pertussis than for detection of Bordetella parapertussis. The fluorescent-antibody method, however, was too insensitive for use without culture.     

Passive transfer of resistance to frambesial infection in hamsters.

The immune mechanism by which hamsters acquire resistance to infection with Treponema pertenue, the causative agent of frambesia, or yaws, has not been elucidated. Serum or cells (spleen or lymph node) obtained from hamsters resistant to frambesial infection were transferred to normal syngenic recipients, who are subsequently infected with T. pertenue. The following parameters were used to measure the ability of immune serum of cells to confer resistance on recipient hamsters to frambesial infection: inhibition of the development of cutaneous lesions, decreased weight, and number of treponemes in the inguinal lymph nodes. This investigation demonstrated that immune serum conferred protection on recipient hamsters infected with T. pertenue. Discontinuation of the administration of immune serum (18 days after frambesial infection) did not result in the development of cutaneous lesions. Since the inguinal lymph nodes contained a sizeable number of treponemes (2.6 X 10(5)), immune serum failed to prevent frambesial infection. Recipients of immune spleen or lymph node cells initially developed frambesial lesions 9 days after infection. The frambesial lesions began to resolve 12 to 14 days after infection and by day 21 had completely regressed. These results illustrated that humoral factors and cells are involved in resistance of the hamster to frambesial infection.     

Role of L3T4+ and 38+ T-cell subsets in resistance against infection with Treponema pallidum subsp. pertenue in hamsters.

The protective immunity conferred by T-cell subsets against infection with Treponema pallidum subsp. pertenue was studied. We demonstrated that hamster T cells can be separated into two subsets by monoclonal antibody (MAb) GK 1.5 (anti-L3T4) and MAb 38. Eighty-five percent of hamster thymocytes were L3T4+ and 87% were 38+ cells; 84% were dual positive for MAbs anti-L3T4 and 38. In the peripheral lymph nodes, however, the L3T4+ and 38+ T cells were mutually exclusive according to two-color immunofluorescence analysis. The two T-cell subsets were found to be functionally distinct according to their secretion of interleukin 2 (IL-2) when stimulated with concanavalin A. The L3T4+ cells secreted IL-2 and had characteristics of T helper cells, while the 38+ cells did not secrete IL-2 and appeared to be T cytotoxic-suppressor cells. Transfer of 4 x 10(6) helper or cytotoxic-suppressor T lymphocytes from T. pallidum subsp. pertenue-immune hamsters protected irradiated naive hamsters against challenge with this subspecies. IL-2 production could still be detected in the irradiated recipients 12 days after irradiation of naive recipients, although at a low level. This suggests that the remaining lymph node cells could support the survival and expansion of the infused cytotoxic-suppressor T cells. No accumulation of macrophages was observed in regional lymph nodes of immune T-cell recipients within 10 days of infection. Instead, there was an influx of polymorphonuclear neutrophils in all animals injected with T. pallidum subsp. pertenue. This report demonstrates that hamster T cells can be separated into two phenotypically and functionally distinct subsets and that both T-cell subsets confer protection against challenge with T. pallidum subsp. pertenue.     

Phagocytosis of opsonized Treponema pallidum subsp. pallidum proceeds slowly.

Macrophages were found to phagocytize Treponema pallidum subsp. pallidum attached to polycarbonate filters. This environment simulated the in vivo interaction of surface-adherent treponemes with macrophages. The phagocytosis of T. pallidum subsp. pallidum was found to proceed slowly. Heat-killed T. pallidum subsp. pallidum were susceptible to opsonization with 2% immune serum, whereas live treponemes were resistant to this concentration of antibody. High concentrations of immune serum were found to increase phagocytosis of the spirochetes. Live T. pallidum subsp. pallidum had bound limited quantities of immunoglobulin G in vivo, and only opsonization with 20% immune serum resulted in a detectable increase in surface-bound immunoglobulin in vitro. Kinetic studies suggested a steady rate of phagocytosis that is considerably slower than with other bacteria. Scanning electron microscopy studies of the phagocytizing macrophages showed that the treponemes were detached from the membrane filters and scooped onto the ruffled portion of the macrophage surface. This lengthy physical process, along with the lack of a dramatic increase in ingestion after opsonization, may account for the slow rate of phagocytosis.