Estimation of nitrogen balance based on a six-hour urine collection in infants

The accuracy of a 6-hr vs a 24-hr urine collection for the determination of urinary urea nitrogen was studied in 15 infants. Patient's age ranged from 2 weeks to 3 yr, encompassing a wide variety of diagnoses. All patients had normal renal function at the time of the study. Participants had indwelling foley catheters throughout the study. Urine specimens were collected over a continuous 24-hr period. Aliquots obtained from urine collected over 0 to 6 hr and the total urine collection were analyzed utilizing the urease enzymatic method in the Astra. Statistical analysis was performed comparing the actual 24-hr determination to the estimation based on the 6-hr collection, utilizing linear regression. The analysis of data produced a highly significant correlation (r = 0.904, p less than 0.0001). When a 24-hr urine collection is not possible, a 6-hr collection is a useful alternative for the calculation of nitrogen balance in infants.     

Application of ECCLS guidelines to the analysis of Toxoplasma IgG and Rubella IgG using laboratory kits based on the Meia method.

The Meia method is an enzymo-immunoassay involving fluorometric detection, which is used in the Abbott IMx automatic analyzer. The purpose of this report was to analyse the Meia Toxoplasma gondii IgG antibody and Rubella IgG antibody assays, following ECCLS guidelines for the analysis of laboratory kits. The results showed that between-run imprecision for Rubella IgG was close to 15%; for Toxoplasma IgG the percentage was 13%. The mean recovery for Rubella IgG was 104% and 94% for Toxoplasma IgG. The carry-over for Rubella IgG was 0.64% and 0.26% for Toxoplasma IgG which, in both cases, was less than the analytical variability. Both Meia and Elisa showed a linear relationship in the analytical range of the method. Comparing Meia with the Elisa method, constant and proportional differences were found for IgG Rubella and proportional differences for IgG Toxoplasma. The Meia method has many positive analytical features to recommend and it can easily be used in a multidisciplinary laboratory, needing only a small number of serum samples.     

Pathophysiology of HPA axis abnormalities in patients with major depression: an update

Four hypotheses have been proposed to explain why nonsuppression on the dexamethasone suppression test occurs in patients with major depression. These include 1) increased metabolism of dexamethasone, 2) decreased sensitivity of pituitary glucocorticoid receptors to dexamethasone, 3) hyperresponsivity of the adrenal gland to ACTH stimulation, and 4) increased central drive of the pituitary from hypothalamic/limbic structures that overrides the action of the dexamethasone. A critical review of the literature suggests that the last hypothesis is most closely supported by the data. Despite this conclusion, factors other than depression may be involved in hypothalamic-pituitary-adrenal axis dysfunction.     

Group protocol to mitigate disaster stress and enhance social support in adolescents exposed to Hurricane Hugo.

Literature reports that cognitive understanding and social support can mitigate stress in both adults and adolescents. As a subcomponent of the Carolina Adolescent Health Project (CAHP), this research evaluated the efficacy of a Cognitive Social Support (CSS) group protocol designed to mitigate the disaster stress of adolescents who had been exposed seriously to Hurricane Hugo. A purposive sample of 259 students participated in and evaluated the CSS. This article reports the specific structure, content, process, rationale, and cost of the CSS. Evaluations indicated that 82% of the students evaluated the small-group component of the CSS as "very good" or "excellent," while 70% rated the large-group component as "very good" or "excellent."     

Partial purification of parathyrin from the corpuscles of Stannius (PCS) of the eel (Anguilla anguilla, L.)

It has been previously shown that the eel corpuscles of Stannius (CS) synthesize and secrete a substance (PCS) which is functionally and immunologically related to the mammalian parathyrin family. Purification of PCS, including anion-exchange chromatography, ODS C-18 reverse-phase HPLC, and affinity chromatography, showed that a biologically active peak, eluted in 32% acetonitrile, contains a 32- to 34-kDa protein which is 600-fold more potent than the crude extract is a test involving the hypocalcemic response in the CS-deprived eel. Specific immunoprecipitation of protein encoded by mRNA extracted from eel CS indicates that a 45-kDa precursor is involved in PCS synthesis. The hypothetical significance of a "large" parathyrin-like molecule in fish is suggested in relation to what is known about mammalian parathyrin gene expression.     

Relevance of HIV-1-specific CD4+ helper T-cell responses during structured treatment interruptions in patients with CD4+ T-cell nadir above 400/mm3

OBJECTIVES: To analyze the dynamics of both HIV-1-specific CD4 and CD8 T-cell responses during structured treatment interruptions (STIs) in chronically HIV-1-infected (CHI) patients and to correlate them with the viral set point achieved. METHODS: Forty-five early-stage CHI patients who were on highly active antiretroviral therapy (HAART) for at least 1 year and underwent STI were included. Plasma viral load (VL), peripheral blood mononuclear cell (PBMC) lymphoproliferative (LPR) response to HIV p24 protein, and HIV-1 epitope-specific interferon-gammarelease from CD8 T cells were measured over a minimum study period of 2 years. RESULTS: VL set point during final STI was both significantly lower than, and positively correlated to, baseline VL (P < 0.0001: mean VL reduction 0.77 log10, and r = 0.42, P = 0.004, respectively). CD4 LPRs to p24 increased significantly (P = 0.001) between day 0 of the first STI cycle and 4th STI but decreased thereafter. VL set point during final STI was significantly and negatively correlated with LPRs to p24 at both 2nd STI and 4th STI. Nevertheless, at week 52, 12 weeks after the end of the last STI, LPRs were weak and transient in all patients and were not correlated with VL set point. Moreover, the magnitude and breadth of HIV-1-specific CD8 T-cell responses increased significantly (P < 0.0001) between day 0 and week 52. The largest increases occurred during the final STI. Even though VL reached set point by week 12 of the final STI, HIV-1-specific CD8 T-cell responses did not stabilize but rather increased until the end of the follow-up and did not correlate with plasma VL (r = 0.01, P = 0.88). CONCLUSIONS: STIs do not lead to control of viral replication in CHI patients, probably due to the fact that boosted CTL responses lack strong and durable helper T-cell responses. To reset the VL set point, new approaches that effectively augment and preserve helper T-cell responses should be investigated.