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Background: The accurate measurement of food intake in children is important for assessing nutritional status., Objective: We sought to both compare measurements of energy intake (EI) from diet records and of total energy expenditure (TEE) by the doubly labeled water (DLW) method and to investigate misreporting of EI., Design: Forty-seven children (22 boys and 25 girls) aged 7.4 +/- 0.8 y ( +/- SD) were recruited from 25 schools in western Sydney. TEE was measured by DLW over 10 d and EI by use of 3-d food records. Misreporting was defined as [(EI - TEE)/TEE] x 100%., Results: Girls had a higher (P = 0.02) percentage of body fat (28.2 +/- 7.0%) than did boys (22.9 +/- 8.0%); otherwise there were no differences among sex. Although mean (+/-SD) values for EI (7514 +/- 1260 kJ/d) and TEE (7396 +/- 1281 kJ/d) were not significantly different, there was no significant correlation between EI and TEE. EI and TEE were 9% and 11% lower, respectively, than current World Health Organization recommendations for EI. The relative bias (mean difference, EI - TEE) was low at 118 kJ/d, but the limits of agreement (bias +/- 2 SD of the difference) were wide at 118 +/- 3345 kJ/d. Although the mean percentage of misreporting was low (4 +/- 23%), the high SD indicates large intraindividual differences between EI and TEE. The most significant predictor of misreporting was dietary fat intake (r(2) = 0.45, P < 0.0001). Misreporting was not associated with sex or body composition., Conclusions: In this age group, reported EI is not representative of TEE at the individual level. However, at the population level, 3-d food records may be used for surveys of EI by 6-9-y-old children.

HLA-B27 is a serologic specificity that encompasses 25 different alleles that encode 23 different products (proteins): HLA-B*2701 to B*2723. These alleles are also called subtypes of HLA-B27, and they may have evolved from the most widespread subtype, B*2705. These subtypes are distinguished from changes mostly in exons 2 and 3, which encode the alpha 1 and alpha 2 domains of the B27 molecule, respectively. Occurrence of ankylosing spondylitis (AS) or related spondyloarthropathy (SpA) has thus far been documented in subjects possessing any one of the first ten (B*2701 to B*2710) subtypes studied. However, B*2706 in Southeast Asian and B*2709 in the Italian island population of Sardinia seem not to be associated with AS. The 13 most recent subtypes have not yet been studied for disease association. It is important to investigate which of them are and are not associated with AS and related SpA, and whether certain subtypes show any preferential association with some of the clinical features or forms of these diseases among the various ethnic/racial populations and geographic regions of the world. This is expected to provide clues as to the mechanism of disease association, and one of the strongest reasons to study the B27 subtypes is to learn the effects of the sequence variations on the peptide-binding specificity of the molecule. Among these peptides may be the putative arthritogenic peptide(s).

Background: The recent worldwide increase in the prevalence of childhood obesity may be due in part to a decrease in children's physical activity levels., Objective: The current study of children in the years just before puberty aimed to 1) measure total energy expenditure (TEE) by use of the doubly labeled water (DLW) method, 2) determine the proportion of TEE related to physical activity, 3) investigate the relations between measures of physical activity and body fatness, and 4) investigate possible sex differences in these relations., Design: The DLW technique was used to measure TEE over 10 d in 106 healthy children (52 boys) aged 7.8 +/- 0.9 y (x +/- SD). Fat-free mass, and hence fat mass, was derived from the (18)O dilution space. Resting energy expenditure (REE) was calculated with use of the Schofield equations. Physical activity level was calculated as TEE/REE., Results: Mean TEE in both boys (7871 +/- 1135 kJ/d) and girls (7512 +/- 1195 kJ/d) was significantly different (P < 0.0001) from FAO/WHO/UNU recommendations (13% and 9% lower, respectively). There was no significant difference in physical activity level between boys (1.69 +/- 0.22) and girls (1.71 +/- 0.23). In boys but not girls, physical activity level was inversely correlated with BMI (r = -0.37, P < 0.01), fat mass (r = -0.46, P < 0.005), and percentage of body fat (r = -0.50, P < 0.0001)., Conclusions: In boys but not girls, percentage of body fat is inversely associated with physical activity level. Physical activity is one factor contributing to body fatness in boys, but additional factors may influence the size of the fat stores in girls.

Disorders of the CYP21 gene, which is located within the major histocompatibility complex on the short arm of chromosome 6, are the leading causes of congenital adrenal hyperplasia (CAH). The coding gene and a highly homologous pseudogene are tandemly arranged with the two genes for the fourth component of complement (C4A and C4B). To analyse the prevalence rates of mutations of the CYP21 genes and the segregation of the CYP21 genes with their corresponding human leucocyte antigen (HLA)-haplotypes, 21 families with one or two children with the severe form of 21-hydroxylase deficiency were studied. Mutations of the CYP21 gene on their corresponding HLA-haplotype were detected by hybridisation of polymerase chain reaction (PCR)-amplified genomic DNA with sequence-specific oligonucleotides and solid phase direct sequencing. Our study has shown the following. (1) A single basepair mutation (A-->G or C-->G) within the second intron is the most frequent mutation leading to impaired 21-hydroxylase activity. This mutation is only detected in HLA-haplotypes associated with the salt-wasting form of CAH. (2) A large deletion of part or all of the CYP21 gene is associated with the HLA-haplotype A3, BW47, C6, DR7, DR53, DQ2 but is also observed in other HLA-haplotypes and can be detected by a simple rapid PCR restriction fragment length polymorphism method. (3) Two alleles of the coding CYP21 gene differing in a leucine codon within the first exon, (formerly described as a mutation associated with 21-hydroxylase deficiency) have been found with an equal distribution in patients with 21-hydroxylase deficiency, non-disease HLA-haplotypes and the local healthy controls.

Previous studies suggested that peripheral blood monocytes (Mo) from HIV-infected patients were poor accessory cells (AC), although most of these studies were limited by using autologous T cells as responders. Using allogeneic T cells from uninfected volunteers as responders, the current studies demonstrate that Mo from infected individuals were comparable to Mo from uninfected volunteers as AC in Con A and pokeweed mitogen-stimulated lymphocyte proliferation assays, but were inferior to normal Mo in stimulating a mixed leukocyte reaction. This deficiency was not explained by HIV Mo-induced suppression of lymphoproliferation or by death of responding CD4 lymphocytes induced by HIV transmission from infected Mo in 6-day MLR cultures. Mo from HIV-infected patients retained the ability to stimulate mumps-specific T cell lines in response to antigen, demonstrating that Mo from these individuals could process and display antigen on their cell surface in association with a functional DR molecule. Taken together these results suggest that Mo from HIV-infected patients (i) retain the ability to act as AC in T cell responses to mitogenic signals or to stimulate already activated antigen-specific T cells, but (ii) fail to stimulate resting and/or unprimed T cells in response to alloantigen and perhaps de novo antigen exposure. It is possible this Mo defect may have an adverse effect on the immune responsiveness of HIV-infected individuals.

Staphylococcal enterotoxin A (SEA) induced the production of interferon-gamma (IFN-gamma) by spleen cells from ICR Swiss mice during the first 24 h of culture. Splenocytes from females produced higher levels of IFN-gamma than did those from males at 8, 12, and 16 h. By 20 h after SEA stimulation, IFN-gamma production by spleen cells from males was similar to that of females. The cell types involved in IFN-gamma production in this SEA/spleen cell system were analyzed by depletion studies. Removal of Thy-1+ cells by panning prevented production of IFN-gamma in the 24 h after SEA stimulation. In vivo depletion of asialo GM1+ (AGM1+) cells prevented production of IFN-gamma through 16 h of culture with SEA, but permitted a modest IFN-gamma response at 20 h that was similar in magnitude in both sexes. Following removal of L3T4+ and Lyt-2+ cells by panning, IFN-gamma production was detected at 12 h after SEA stimulation and maintained through 24 h of culture with cells from females producing higher levels of IFN-gamma. These data suggest that male ICR Swiss mice are deficient in the activity of Thy-1+, AGM1+, L3T4-, and Lyt-2- cells in the early (8-16 h) production of IFN-gamma following SEA stimulation of spleen cells.

Human leukocyte antigen (HLA) typing was performed in 174 patients with rheumatoid arthritis and 222 white control subjects. Increases in HLA-DR4 and HLA-DR1 were observed as in previous studies. Each of these appeared to be inherited as dominant risk factors. Southern blotting with a DR-beta probe after digestion of genomic DNA with the restriction enzyme Bam HI showed seven bands. Three of them correlated with DR4 and were increased in rheumatoid arthritis patients. Subsets of DR4 were determined by polymerase chain reaction amplification followed by hybridization with oligonucleotide probes. Dw4 was increased in rheumatoid arthritis patients, and the frequency of the other subsets appeared to be similar in rheumatoid arthritis patients and control subjects. A polymorphism associated with the T cell receptor V-beta-8 gene family was significantly increased in rheumatoid arthritis patients.

Previous studies have demonstrated restriction fragment length polymorphisms (RFLP) in the vicinity of the alpha and beta genes of the human T-cell receptor. In the course of experiments designed to discover additional polymorphic restriction sites, we found a new RFLP of the T-cell alpha gene recognized by the restriction enzyme Taq I. The site was localized to the interval between the most 3' joining (J) exon and the most 5' constant (C) region exon, about 7 kb distant from the previously described Bgl II polymorphic site which mapped to the vicinity of the 3' untranslated exon. With the use of these two polymorphic markers, four Ti-alpha alleles could be identified, allowing unambiguous assignment of all Ti-alpha genes in some families. These markers may be useful in identifying possible immune response genes or disease predisposition genes associated with the genes of the T-cell receptor for antigen.

Attempts to further define the antigens recognized by HLA-D-region specific cytotoxic lymphocytes were undertaken using monocytes and transformed B cell lines as target cells. Monoclonal antibody against framework determinants of HLA-DR antigens partially blocked cell mediated lysis, suggesting that at least a portion of the D-region specific cytotoxic cells recognized the HLA-DR determinants. The study of a family with an HLA-B/DR recombinant showed that the determinants recognized by allogeneic anti-HLA-D-region cytotoxic lymphocytes are encoded outside of HLA-B. In addition, cytotoxic lymphocytes specific for the HLA-D region could be generated with cells identical throughout the interval from HLA-A to B and disparate only to the left of HLA-B.

The results presented provide evidence that the HLA specificity known as MT3, BR4, or Hon7 can serve as a restriction epitope for the proliferation of certain T cells responding to mumps viral antigen. This restriction determinant was found to be HLA-linked in family studies, and to segregate centromeric to a crossover between HLA-B and DR in one family. In the population studied, the specificity was found to be associated with the DR antigens DR4, DR7, and DRw9, which are known to be associated with MT3. The ability of accessory cells to present mumps antigen in the context of this supertypic restriction determinant was blocked by a monoclonal antibody specific for MT3. Since MT3 (BR4, Hon7) has been shown to be expressed on molecules distinct from DR, our experiments suggest that such molecules are functionally important in antigen presentation to T cells.

The ability of cells with different amounts of HLA-DQ or -DR to support T-cell proliferation in response to foreign antigens was investigated. Adherent cells were stained with monoclonal antibodies and sorted in the fluorescence-activated cell sorter (FACS) into (a) DQ-positive and DQ-negative subsets, with monoclonal anti-DQ; or (b) subsets expressing different density of DR determinants. Expression of HLA-DQ correlated with increased density of DR. The subset of cells expressing detectable DQ and increased density of DR was found to be more efficient in presenting mumps or tetanus toxoid antigen to T cells than were the DQ-negative, low-DR density adherent cells. Similar results were obtained with primary cultures of T cells from blood and with cloned antigen-specific T-cell lines, restricted by a single DR-subregion specificity. Our results suggest that quantitative variation in DR/DQ molecules expressed on monocytes correlates with their ability to support T-cell responses to nominal antigens. It is not clear whether this is due to only class II antigen density on the surface of the accessory cells or whether other factors are involved.