Characterization of creatinine error in ketotic patients. A prospective comparison of alkaline picrate methods with an enzymatic method

Creatinine measurement by alkaline picrate reagents is subject to positive interference by acetoacetate. Enzymatic reagents avoid this interference and have been adapted to instruments such as the Ektachem-400 (Kodak). By documenting the discrepancy between alkaline picrate and Ektachem determinations for creatinine, the authors prospectively identified ketotic patients in whom the presence of ketones was responsible for a significant creatinine error. During their three-month survey, they identified 50 such ketotic inpatients. Those admitted to the medicine service represented almost 5% of all medicine admissions over this time. Of the total specimens, the mean discrepancy was 14 +/- 8 mg/L with a range of 4-44 mg/L. The greater the ketosis, the greater the discrepancy. Two-thirds of the samples were normal on the Ektachem but greater than normal by picrate methods. In addition to diabetes or ethanol abuse, 17% of the ketotic patients had severe or terminal illness that was generally associated with malnutrition.     

Effect of hydrostatic pressure on ADH induced osmotic water flow in toad bladder

The effect of hydrostatic pressure (HP) on antidiuretic hormone (ADH) stimulated osmotic water flow (Jv) across the toad urinary bladder was evaluated. Jv for ADH-stimulated bladders was significantly reduced by an elevation of the serosal HP gradient to 1 cm H₂O. Subsequent elimination of the HP gradient resulted in a recovery of Jv. Serosal HP also caused a reversible increase in sucrose permeability (P sucrose). For ADH-treated bladders fixed with glutaraldehyde during serosal HP exposure, subsequent exposure to a mucosal or serosal HP gradient caused acceleration or inhibition of Jv, respectively. The reduction in ADH-associated Jv with serosal HP was apparently caused by a back-flux of water through a paracellular pathway. Jv and P sucrose were not affected by mucosal HP during ADH stimulation. The results suggest a specific sensitivity of a paracellular pathway to a small serosal HP gradient in bladders with ADH-stimulated water flow. The reversibility of this effect on P sucrose suggests that the elements comprising the apical junctions are dynamic structures capable of recovering at least some of their permeability properties.     

Abeta-degrading endopeptidase,neprilysin, in mouse brain: synaptic and axonal localization inversely correlating with Abeta pathology

Metabolism of amyloid-beta peptide (Abeta) is closely associated with the pathology and etiology of Alzheimer's disease (AD). Since neprilysin is the only rate-limiting catabolic peptidase proven by reverse genetics to participate in Abeta metabolism in vivo, we performed detailed immunohistochemical analysis of neprilysin in mouse brain using neprilysin-deficient mice as a negative control. The aim was to assess, at both the cellular and subcellular levels, where Abeta undergoes neprilysin-dependent degradation in the brain and how neprilysin localization relates to Abeta pathology in amyloid precursor protein (APP)-transgenic mice. In hippocampus, neprilysin was present in the stratum pyramidale and stratum lacunosum-moleculare of the CA1-3 fields and the molecular layer of the dentate gyrus. Confocal double immunofluorescence analyses revealed the subcellular localization of neprilysin along axons and at synapses. This observation suggests that after synthesis in the soma, neprilysin, a type II membrane-associated protein, is axonally transported to the terminals, where Abeta degradation is likely to take place. Among various cell types, GABAergic and metabotropic glutamate 2/3 receptor-positive neurons but not catecholaminergic or cholinergic neurons, expressed neprilysin in hippocampus and neocortex, implying the presence of a cell type-specific mechanism that regulates neprilysin gene expression. As expected, Abeta deposition correlated inversely with neprilysin expression in TgCRND8 APP-transgenic mice. These observations not only support the notion that neprilysin functions as a major Abeta-degrading enzyme in the brain but also suggest that down-regulation of neprilysin activity, which may be caused by aging, is likely to elevate local concentrations of Abeta at and around neuronal synapses.     

Induced recruitment of NK cells to lymph nodes provides IFN-gamma for T(H)1 priming

Naive T cells are stimulated by antigen-presenting dendritic cells (DCs) in secondary lymphoid organs, but whether other types of cell participate in T cell priming is unclear. Here we show in mice that natural killer (NK) cells, which are normally excluded from lymph nodes, are rapidly recruited in a CCR7-independent, CXCR3-dependent manner to lymph nodes on stimulation by the injection of mature DCs. Recruitment of NK cells is also induced by some, but not all, adjuvants and correlates with the induction of T helper cell type 1 (T(H)1) responses. NK cell depletion and reconstitution experiments show that NK cells provide an early source of interferon-gamma (IFN-gamma) that is necessary for T(H)1 polarization. Taken together, our results identify an induced pathway of NK cell migration in antigen-stimulated lymph nodes and a mechanism by which some adjuvants may facilitate T(H)1 responses.     

High risk pregnancies in hypopituitary women

BACKGROUND: Various short papers have suggested that pregnancies in women with hypopituitarism are high risk but no formal assessment of pregnancy outcome has yet been reported. METHODS: An audit was carried out concerning the outcome of 18 pregnancies in nine women who underwent ovulation induction in a single centre over 20 years. RESULTS: The live birth rate was 61%, miscarriage rate 28% and mid-trimester uterine death rate 11% with no survivors from four sets of twins. The Caesarian section rate was 100% and half of the live births were on or below the 10th centile for weight. One woman successfully breast-fed. CONCLUSIONS: Women with hypopituitarism have high-risk pregnancies, perhaps because of a uterine defect secondary to endocrine deficiency. Fertility treatment must strive for singleton pregnancies with application of particularly strict criteria to avoid twin pregnancies. Early elective Caesarian section is probably warranted in this group.     

Rapid diagnosis of smallpox infection and differentiation from its mimics.

The potential for a bioterrorism-induced smallpox outbreak has been much discussed of late. The literature of the late 1960s stressed that the distinction between smallpox and the other viral-induced vesicle-forming diseases, namely varicella zoster and disseminated herpes simplex, was difficult to make. Given that the cutaneous manifestations of smallpox would be among the initial symptoms, we reviewed 2 cases of smallpox diagnosed in South America in the 1970s in conjunction with 9 cases of multiple skin vesicles diagnosed as either disseminated herpes simplex or varicella-zoster. These were examined by routine hematoxylin and eosin stain (H&E) as well as by in situ hybridization. A blind review of the cases demonstrated that each showed striking intraepithelial vesicles containing multinucleated squamous cells exhibiting a ground glass appearance of the nuclear chromatin. Thus, as expected, routine H&E examination could not differentiate the 2 smallpox cases from the other 9 samples. In situ hybridization easily distinguished the 2 cases of smallpox from the other 9 samples, 5 of which contained varicella-zoster (two had been misdiagnosed as herpes) and the other 4 were disseminated herpes simplex. The in situ test, readily accomplished in any histology-based molecular laboratory in 4 hours, allows for the rapid and specific identification of smallpox infection and, importantly, its distinction from its mimics. Formalin fixation, which is optimal for in situ hybridization, guarantees the inactivation of the smallpox virus.     

Low elementary movement speed is associated with poor motor skill in Turner's syndrome

The article aims to discriminate between 2 features that in principle both may be characteristic of the frequently observed poor motor performance in girls with Turner's syndrome (TS). On the one hand, a reduced movement speed that is independent of variations in spatial accuracy demands and therefore suggests a problem in motor execution. On the other hand, a disproportional slowing down of movement speed under spatial-accuracy demands, indicating a more central problem in motor programming. To assess their motor performance problems, 15 girls with TS (age 9.6-13.0 years) and 14 female controls (age 9.1-13.0 years) were tested using the Movement Assessment Battery for Children (MABC). In additionally, an experimental procedure using a variant of Fitts' graphic aiming task was used to try and disentangle the role of spatial-accuracy demands in different motor task conditions. The results of the MABC reestablish that overall motor performance in girls with TS is poor. The data from the Fitts' task reveal that TS girls move with the same accuracy as their normal peers but show a significantly lower speed independent of task difficulty. We conclude that a problem in motor execution is the main factor determining performance differences between girls with TS and controls.     

Phosphoinositide deficiency due to inositol depletion is not a mechanism of lithium action in brain

The "inositol depletion hypothesis" has been widely held to be the explanation for both the effect of lithium on brain function, apropos of its use in mood disorders, and on the impairment of development and induction of embryonic malformations in diverse organisms. The essence of the hypothesis is that a deficiency in cellular myo-inositol (Ins), secondary to lithium inhibition of inositol monophosphatase and/or multiple inositol polyphosphate phosphatase activities with trapping of Ins as inositol phosphates, leads to a depression of phosphatidylinositol (PtdIns) and a secondary impairment in inositide signaling. However, the ability of relatively low micromolar levels of Ins to reduce mammalian PtdIns synthetase activity in vivo has never been adequately tested. We have generated a lethal murine brain Ins deficiency model and measured PtdIns content using a novel MALDI-TOF MS method. Our results show that in the most severe Ins deficiency ever recorded in a mammal, the brain PtdIns levels do not decrease. We conclude that PtdIns deficiency due to "inositol depletion" is not a mechanism of lithium action in brain, and that Ins plays another unidentified role in the mammalian brain.