Metabolic impact of adenovirus-mediated overexpression of the glucose-6-phosphatase catalytic subunit in hepatocytes

Glucose-6-phosphatase (G6Pase) catalyzes the hydrolysis of glucose 6-phosphate (Glu-6-P) to free glucose and, as the last step in gluconeogenesis and glycogenolysis in liver, is thought to play an important role in glucose homeostasis. G6Pase activity appears to be conferred by a set of proteins localized to the endoplasmic reticulum, including a glucose-6-phosphate translocase, a G6Pase phosphohydrolase or catalytic subunit, and glucose and inorganic phosphate transporters in the endoplasmic reticulum membrane. In the current study, we used a recombinant adenovirus containing the cDNA encoding the G6Pase catalytic subunit (AdCMV-G6Pase) to evaluate the metabolic impact of overexpression of the enzyme in primary hepatocytes. We found that AdCMV-G6Pase-treated liver cells contain significantly less glycogen and Glu-6-P, but unchanged UDP-glucose levels, relative to control cells. Further, the glycogen synthase activity state was closely correlated with Glu-6-P levels over a wide range of glucose concentrations in both G6Pase-overexpressing and control cells. The reduction in glycogen synthesis in AdCMV-G6Pase-treated hepatocytes is therefore not a function of decreased substrate availability but rather occurs because of the regulatory effects of Glu-6-P on glycogen synthase activity. We also found that AdCMV-G6Pase-treated-cells had significantly lower rates of lactate production and [3-3H]glucose usage, coupled with enhanced rates of gluconeogenesis and Glu-6-P hydrolysis. We conclude that overexpression of the G6Pase catalytic subunit alone is sufficient to activate flux through the G6Pase system in liver cells. Further, hepatocytes treated with AdCMV-G6Pase exhibit a metabolic profile resembling that of liver cells from patients or animals with non-insulin-dependent diabetes mellitus, suggesting that dysregulation of the catalytic subunit of G6Pase could contribute to the etiology of the disease.     

Specific bronchial provocation tests with flour in the diagnosis of occupational bronchial asthma

The gold standard in the diagnosis of occupational asthma is the specific bronchial provocation test (sBPT), but other diagnostic criteria have been proven to have a similar sensitivity, mainly in asthma due to high molecular weight compounds. In order to assess wether some clinical findings can predict the positive response to sBPT, we studied 37 subjects (14 millers and 23 bakers) with suspected occupational asthma who underwent sBPT with wheat flour dust (dust exposure in a small cabin: geometric mean 12.1 mg/m3 for up to 30 min). A positive response to sBPT (FEV1 > 20%) was elicited in 20 subjects (11 early, 4 late, and 5 dual responses). There was no significant difference between subjects with positive or negative sBPT as regards mean age, smoking, length of employment, duration of symptoms, atopy (skin positivity to one or more common allergens) and PD20FEV1 methacholine. The percentage of subjects with work-related symptoms was significantly higher in subjects with positive sBPT with respect to subjects with negative sBPT (81% versus 41.2%, p < 0.01 by chi 2 test); furthermore, FEV1 was significantly lower in subjects with positive sBPT. The percentage of positive skin response to wheat flour extract (mean wheal diameter > or = 3 mm) was mildly but not significantly higher in subjects with positive sBPT (68.4% versus 41.2%). None of the following clinical factors (age < 35 years, asthma symptoms pre-existing occupational exposure, non smokers, atopy and bronchial hyperresponsiveness to methacholine), alone or in combination, were associated with higher prevalence of positive sBPT. We conclude that the response to sBPT in subjects with suspected occupational asthma due to flour dust can not be adequately predicted by other clinical, allergologic and functional data. Therefore, sBPT with flour dust should always be performed in subjects with suspected occupational asthma.     

AbdB-like Hox proteins stabilize DNA binding by the Meis1 homeodomain proteins

Recent studies show that Hox homeodomain proteins from paralog groups 1 to 10 gain DNA binding specificity and affinity through cooperative binding with the divergent homeodomain protein Pbx1. However, the AbdB-like Hox proteins from paralogs 11, 12, and 13 do not interact with Pbx1a, raising the possibility of different protein partners. The Meis1 homeobox gene has 44% identity to Pbx within the homeodomain and was identified as a common site of viral integration in myeloid leukemias arising in BXH-2 mice. These integrations result in constitutive activation of Meis1. Furthermore, the Hoxa-9 gene is frequently activated by viral integration in the same BXH-2 leukemias, suggesting a biological synergy between these two distinct classes of homeodomain proteins in causing malignant transformation. We now show that the Hoxa-9 protein physically interacts with Meis1 proteins by forming heterodimeric binding complexes on a DNA target containing a Meis1 site (TGACAG) and an AbdB-like Hox site (TTTTACGAC). Hox proteins from the other AbdB-like paralogs, Hoxa-10, Hoxa-11, Hoxd-12, and Hoxb-13, also form DNA binding complexes with Meis1b, while Hox proteins from other paralogs do not appear to interact with Meis1 proteins. DNA binding complexes formed by Meis1 with Hox proteins dissociate much more slowly than DNA complexes with Meis1 alone, suggesting that Hox proteins stabilize the interactions of Meis1 proteins with their DNA targets.     

An optimization study on unprogrammed cryopreservation of human CD34+ bone marrow cells and their subsequent storage in an -80 degrees C mechanical freezer

Forty-one patients for whose direct care at least one machine was used and 33 registered nurses from the same five non-critical care units as the patients and from one related unit, participated in a semistructured tape-recorded interview to identify the core categories of the human-machine interface in clinical nursing practice and the relationships between them. Constant comparative analysis was used to organize and process the data. Patients perceived the machines as neutral because of their view of health care and because nurses were the interface between them and the machines. Nurses perceived the machines as either positive or negative, depending on their effect on the nurses' professional competence and the extent to which they worked directly with them.     

The granulomatous response in murine Schistosomiasis mansoni does not switch to Th1 in IL-4-deficient C57BL/6 mice

IL-4 plays an important role in polarizing inflammation toward a Th2 response. It remains uncertain, however, whether IL-4 also serves to prevent expression of Th1 inflammation. Therefore, using a genetically pure C57BL/6 IL-4-deficient mouse, we studied the role of IL-4 in regulating the production of IFN-gamma and Th1 inflammation in the granulomas of mice infected with Schistosoma mansoni. In contrast to normal animals, IL-4 mutant mice generated smaller liver granulomas that contained fewer eosinophils and no mast cells. Collagenase-dispersed granuloma cells were analyzed by flow cytometry and cultured in vitro to measure cytokine and Ig production. Compared with control granuloma cells, IL-4-/- cells secreted only small quantities of IL-5 and IL-10. Also, there was impaired expression of the IL-4-dependent molecules IgE and IgG1 as well as B cell surface class II and CD23. Yet the granulomas of IL-4 -/- animals produced little IFN-gamma, IgG2a, or other molecules associated with Th1 inflammation even after Ag or anti-CD3 stimulation. Splenocytes from IL-4 -/- animals stimulated with schistosome Ag also failed to produce a Th1 response. Our data show that most aspects of the Th2 response in murine schistosomiasis are highly dependent on IL-4 production. But in the absence of IL-4, neither the natural local granulomatous response to schistosome ova nor the systemic response to soluble egg Ag switches to the type 1 phenotype. Thus the production of IL-4 early in the inflammatory response is not the only factor preventing Th1 expression in inflammation.     

Lipid peroxidation and lysosomal integrity in different inflammatory models in rats: the effects of indomethacin and naftazone

The authors tried to establish quantitative and qualitative acoustic parameters of a good voice, suitable for future voice professionals. In their work they used long-time average spectrum analysis (LTAS) and three-dimensional analysis of periodicity (3D-PAN). They consider the regression straight line of formant regions and the parameters offered by 3D-PAN--jitter first of all--as the main acoustic parameters for the evaluation of voice quality and draw attention to the fact that acoustic parameters represent only one part of the evaluation of voice quality.     

Prevalence of serologic markers of HBV, HDV, HCV and HIV in non-injection drug users compared to injection drug users in Gran Canaria, Spain

Von Hippel-Lindau disease (VHL) is an autosomal dominant tumour syndrome caused by germline mutations of the VHL tumour suppressor gene located on chromosome 3p25-26. In VHL tumours may occur in 14 different target organs, including the eye. Retinal angiomas are considered the first manifestation of VHL disease in 43% of cases, and the cumulative probability of developing a retinal angioma in one or both eyes rises during each decade of life, reaching 80% for patients over 80 years old. Since 1976 patients with VHL at the University Hospital of Utrecht and their at-risk relatives have been screened periodically by a multidisciplinary team. Long-term follow-up ophthalmological data were analysed with special attention to natural course and results of treatment. In addition, we looked for a genotype-phenotype correlation. Retinal angiomas were found in all families. In one large family with a missense mutation (V170D) of the VHL gene, in which the complete spectrum of visceral- and central nervous system (CNS) features of VHL is present, macular, parapapillary, optic disc and ora serrata angiomas were also found. In general, however, a clear-cut genotype-phenotype correlation could not be found. Only early detection and treatment of peripheral retinal angiomas can be expected to decrease the percentage of patients with decreased visual acuity. Therefore, early detection and treatment of these tumours is of paramount importance. Ophthalmological screening of patients and persons at risk should start as early as possible. In patients with apparently sporadic retinal angiomas it is advisable to perform germline DNA analysis, since the risk of developing VHL is high, especially if the angiomas are bilateral, or unilateral and multifocal, if the patient is young, or if there is a family history suggestive of VHL.