DXA-Generated Z-Scores and T-Scores May Differ Substantially and Significantly in Young Adults

Central dual-energy X-ray absorptiometry (DXA) is the gold standard for non-invasive measurement of bone mineral density (BMD). Using this value and subject demographics, DXA software calculates T-scores and Z-scores. Professional society guidelines for the management of osteoporosis are based on T-scores and Z-scores, rather than on the actual BMD value. Although one expects T-scores and Z-scores to be very similar in young men and women for any given BMD measurement, little literature exists on this issue. Our clinical experience shows that some younger adult individuals (premenopausal women and men younger than 50 yr) have larger than expected difference between their DXA T-score and Z-score. This cross-sectional study evaluates the extent of this discordance between Z-scores and T-scores in a sample of 4275 men and women aged 20–49 yr. All subjects were scanned by central DXA using equipment manufactured by GE Lunar, GE, Madison, WI, or Hologic, Inc., Bedford, MA. Significant differences between Z-scores and T-scores were seen within individuals at the lumbar spine, total hip, femoral neck, and trochanter (p value < 0.001) for both DXA systems. Although these differences were less than half a standard deviation (SD) in most instances, the magnitude of difference was substantial at times, being 1 or more SD in up to 11% of cases (range: −1.95 to +1.54 SD). The smallest differences were seen at the total hip and the largest differences were seen at the femoral neck for both technologies. This is in part because there is no single standard Z-score definition, resulting in different methods of calculation across, and even within, DXA manufacturers. Standardization of Z-score definition and method of calculation is indicated. DXA Z-scores should be interpreted with caution in men and women aged 20–50 yr.     

A preventive intervention for enhancing resilience among highly stressed urban children

Describes the development and evaluation of a pilot 12-session, school-based preventive intervention designed to enhance resilience among inner-city children who have experienced major life stress. Thirty-six 4th–6th grade children participated in the intervention in groups of 5–8 co-led by school personnel. The curriculum focussed on understanding feelings in oneself and others, perspective-taking, social problem-solving, dealing with solvable and unsolvable problems, and building self-efficacy and esteem. Pre-post evaluation showed significant improvement among participants on teacher-rated indices of learning problems and task orientation and on child ratings of perceived self-efficacy, realistic control attributions and anxiety. Program limitations and factors that restrict generalization are considered and new directions for program development and research are proposed.     

Hepatic DNA adduct dosimetry in rats fed tamoxifen: a comparison of methods

Liver homogenates from rats fed tamoxifen (TAM) in the diet were shared among four different laboratories. TAM-DNA adducts were assayed by high pressure liquid chromatography-electrospray tandem mass spectrometry (HPLC-ES-MS/MS), TAM-DNA chemiluminescence immunoassay (TAM-DNA CIA), and (32)P-postlabeling with either thin layer ((32)P-P-TLC) or liquid chromatography ((32)P-P-HPLC) separation. In the first study, rats were fed a diet containing 500 p.p.m. TAM for 2 months, and the values for measurements of the (E)-alpha-(deoxyguanosin-N(2)-yl)-tamoxifen (dG-N(2)-TAM) adduct in replicate rat livers varied by 3.5-fold when quantified using 'in house' TAM-DNA standards, or other approaches where appropriate. In the second study, rats were fed 0, 50, 250 or 500 p.p.m. TAM for 2 months, and TAM-DNA values were quantified using both 'in house' approaches as well as a newly synthesized [N-methyl-(3)H]TAM-DNA standard that was shared among all the participating groups. In the second study, the total TAM-DNA adduct values varied by 2-fold, while values for the dG-N(2)-TAM varied by 2.5-fold. Ratios of dG-N(2)-TAM:(E)-alpha-(deoxyguanosin-N(2)-yl)-N-desmethyltamoxifen (dG-N(2)-N-desmethyl-TAM) in the second study were approximately 1:1 over the range of doses examined. The study demonstrated a remarkably good agreement for TAM-DNA adduct measurements among the diverse methods employed.     

Inherited partial duplication of chromosome No. 15

A boy with unusual facial appearance and mental retardation was found to have duplication for the distal half of the long arm of chromosome No. 15 and possibly deficiency for the distal end of the long arm of No. 21. The chromosome abnormality was inherited from his mother, who had a translocation involving chromosomes Nos. 15 and 21. Giemsa-banding localized the break point in chromosome No. 15 just distal to the intense band at the midportion of the long arm. The break point in chromosome No. 21 appeared to be at the distal end of the long arm. The difficulty encountered in cytogenetic analysis of the propositus with conventional staining, the importance of chromosome analysis of the parents, and the application of differential staining techniques are also presented.     

Human herpesvirus 8 infection among various population groups in southern Israel

OBJECTIVE: To compare the prevalence of antibodies to human herpesvirus 8 (HHV-8) or Kaposi sarcoma-associated herpesvirus among Israeli and Ethiopian subjects. METHODS: Serum samples were obtained from 98 Israeli Jewish students aged 18-30 years, 100 HIV-1-seronegative Ethiopian immigrants to Israel of the same age, and 100 HIV-1-seronegative Ethiopian children 1-12 years old upon their arrival in southern Israel. Plasma samples were obtained from 3 hospitalized patients with multicentric Castleman disease (MCD) as positive controls. All serum samples were tested for antibodies to both latent and lytic antigens. Antibodies to the lytic antigens and the latency-associated nuclear antigen (LANA) of HHV-8 were detected by enzyme linked immunosorbent assay and by immunofluorescence assay. HHV-8 DNA from serum or plasma samples was detected by polymerase chain reaction analysis. RESULTS: Antibodies to HHV-8 LANA were detected in 2.9% of the Israeli subjects aged 18-30 years and in 26% of the Ethiopian subjects from both age groups tested. Antibodies to the lytic antigens were detected in all 3 MCD patients, in 4% of the Ethiopian children, and in 2% of the 18- to 30-year-old Ethiopians. No antibodies to the lytic antigens were detected in the Israeli students. HHV-8 DNA was detected in all 3 MCD patients and in 2 of 4 of the Ethiopian children positive for the lytic antigens. CONCLUSIONS: HHV-8 is highly prevalent in Ethiopian immigrants to Israel as compared with Israeli students. Antibodies to HHV-8 in Ethiopia are acquired before puberty. The results of this study indicate the association of HHV-8 with MCD, as has been documented by many other researchers.     

A test of the assumptions of the transtheoretical model in a post-traumatic stress disorder population

Prior reports suggest an ambivalence regarding treatment in individuals with Post-Traumatic Stress Disorder (PTSD). A model that accommodates such ambivalence is the Transtheoretical Model of Behavior Change (TTM, also known as the Stages-of-Change Model). Fifty veterans presenting for treatment completed self-report measures (94% response rate) that assessed disorder variables and constructs relating to the TTM. While the relationships between the components of each specific construct were found to be consistent with the findings of other studies and a number of predicted relationships between variables were confirmed, many results were inconsistent with the TTM. Notwithstanding questions about the suitability of the self-report measures, the unique characteristics of the veteran sample and the small sample size, the results suggest that the assumptions of the TTM were not met in veterans with PTSD. Copyright © 2005 John Wiley & Sons, Ltd.     

Longitudinal study of daily variation of rats' behavior in the elevated plus-maze

We conducted a longitudinal study about daily variation of Wistar male rats' behavior in the elevated plus-maze (EPM) evaluated in the 1st, 2nd, 3rd, 6th, 12th, and 18th months of life. Animals were submitted to the plus-maze in 12 sessions at 2-h intervals (n=72, 6 per time point). Spontaneous rest-activity rhythm of four animals was assessed by observation of 24-h videotape records. Time series were analyzed by Cosinor method. Behavioral rates on the six occasions and in light and dark phases were compared by means of two-way ANOVA with repeated measures. Exploratory behavior in EPM was smaller in the light phase and in older animals. Higher values of open and closed arms exploration were observed in the first and third months of the dark phase, and in the first month of the light phase. Adjustment to the 24-h period was significant at all stages for rest-activity data, number of entries in closed arms, and time on center, and for three to five stages for open-arm exploration. In general, 24 h variability was more pronounced in younger animals compared with older ones. The present study showed that: (1). a significant amount of total variability of the behavioral indexes analyzed could be attributed to 24 h variation, (2). light/dark phases differences in EPM exploration were present at all developmental stages, (3). older Wistar rats explored less the EPM and were less active in their home cage compared with younger ones, and (4). behavioral indexes (EPM) decrease was phase related and partially related to a reorganization of rest-activity rhythm.