Time course of the induction of aryl hydrocarbon hydroxylase in rat liver nuclei and microsomes by phenobarbital, 3-methylcholanthrene, 2,3,7,8-tetrachloro-dibenzo-p-dioxin,dieldrin and other inducers

Aryl hydrocarbon hydroxylase (AHH) has been measured in male rat liver nuclei and microsomes after treatment of adult animals with various inducers for up to 14 days. After daily i.p. injections of 3-methylcholanthrene (MC, 20 mg/kg) the nuclear activity increased to a maximum of 600 per cent of the control activity after 4 days whereas the microsomal activity was 400 per cent of control at the same date. After 12 days, both activities equilibrated at 400 per cent. A similar time course was found after a single i.p. injection of 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD, 0.01 mg/kg) with an induction to 500 and 300 per cent for nuclei and microsomes, respectively, after 2 days, and to 400 per cent for both after 12 days. Phenobarbital (PB) was given continuously in the drinking water (1 g/l) and induced the microsomal activity to 200 per cent after 8 days and 170 per cent after 14 days. the nuclear activity was only slightly induced to a Constant level of 130 per cent between day 8 and 14. Dieldrin did not significantly increase the microsomal activity after daily i.p. injections (20 mg/kg), but the nuclear activity raised to 200 per cent after 3 days and levelled down to control values after 12 days. Other inducers tested were benz[a]anthracene (BA), hexachlorobenzene (HCB) and 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT). The induction pattern with BA was similar to that of MC, a model compound for the group of cytochrome P448 inducers. the induction by HCB and DDT resembled that by PB, a typical cytochrome P450 inducer.     

Gene-nutrient interactions in one-carbon metabolism

Advances in molecular biology greatly contributed, in the past decades, to a deeper understanding of the role of gene function in disease development. Environmental as well as nutritional factors are now well acknowledged to interact with the individual genetic background for the development of several diseases, including cancer, cardiovascular disease, and neurodegenerative diseases. The precise mechanisms of such gene-nutrient interactions, however, are not fully elucidated yet. Many micronutrients and vitamins are crucial in regulating mechanisms of DNA metabolism. Indeed, folate has been most extensively investigated for its unique function as mediator for the transfer of one-carbon moieties for nucleotide synthesis/repair and biological methylation. Cell culture, animal, and human studies, clearly demonstrated that folate deficiency induces disruption of DNA synthesis/repair pathways as well as DNA methylation anomalies. Remarkably, a gene-nutrient interaction between folate status and a polymorphism in methylenetetrahydrofolate reductase gene has been reported to modulate genomic DNA methylation. This observation suggests that the interaction between a nutritional status and a mutant genotype may modulate gene expression through DNA methylation, especially when such polymorphism affects a key enzyme in one-carbon metabolism and limits the methyl supply. DNA methylation, both genome-wide and gene-specific, is of particular interest for the study of aging, cancer, and other pathologic conditions, because it affects gene expression without permanent alterations in the DNA sequence such as mutations or allele deletions. Understanding the patterns of DNA methylation through the interaction with nutrients is a critical issue, not only to provide pathophysiological explanations of a disease state, but also to identify individuals at-risk to conduct targeted diet-based interventions.     

Improving the reproducibility of diagnosing micrometastases and isolated tumor cells

BACKGROUND: The latest edition of the tumor-lymph node-metastasis (TNM) classification of malignant tumors distinguishes between isolated tumor cells (pN0) and micrometastases (pN1mi). The reproducibility of these categories has not been assessed previously. METHODS: Digital images from 50 cases with low-volume lymph node involvement from axillary sentinel lymph nodes were circulated twice for evaluation (Evaluation Rounds 1 and 2) among the members of the European Working Group for Breast Screening Pathology, and the members were asked to categorize lesions as micrometastasis, isolated tumor cells, or something else and to classify each case into a pathologic lymph node (pN) category of the pathologic TNM system. Methods for improving the low reproducibility of the categorizations were discussed between the two evaluation rounds. kappa Statistics were used for the assessment of interobserver variability. RESULTS: The kappa value for the consistency of categorizing low-volume lymph node load into micrometastasis, isolated tumor cells, or neither of those changed from 0.39 to 0.49 between Evaluation Rounds 1 and 2, but it was slightly lower for the pN categories (0.35 and 0.44, respectively). Interpretation of the definitions of isolated tumor cells (especially with respect to their localization within the lymph node), lack of guidance on how to measure them if they were multiple, and lack of any definitions for multiple simultaneous foci of lymph node involvement were listed among the causes of discordant diagnoses. CONCLUSIONS: The results of the current study indicated that the definitions available have minor contradictions and do not permit a reproducible distinction between micrometastases and isolated tumor cells. Refinement of these definitions, therefore, is required. One refinement that may improve reproducibility is suggested in this report.     

Control of imported and acquired methicillin-resistant Staphylococcus aureus (MRSA) in mechanically ventilated patients: a dose-response study of enteral vancomycin to reduce absolute carriage and infection

This study aimed to quantify the animate source provided by the patients using the concept of "absolute carriage" by multiplying the carrier rate by the level of carriage; and to compare the impact of a low and high dose of an oropharyngeal vancomycin gel on the absolute MRSA carriage and infection. In all, 265 patients were included, 126 were MRSA positive. Fifty-five patients received 2% vancomycin gel during the first year whilst 4% vancomycin gel was given to 50 patients during the second year. Surveillance swabs of throat and rectum were obtained from all eligible patients on admission and then twice weekly. The vancomycin protocol was started as soon as the surveillance cultures were positive for MRSA. Those patients received one gram of enteral vancomycin daily, divided into four doses. During the first year 2% vancomycin gel 4 ml (80 mg) was applied in the oropharynx in four doses in addition to the enteral solution (Group A). During the second year 4% vancomycin gel 4 ml (160 mg) was used (Group B). The absolute carriage was high during both periods: 3.6 for Group A, and 3.2 for Group B. The 4% vancomycin protocol significantly reduced the absolute carriage, compared to the 2% vancomycin protocol: 2.6 versus 1.5 (P < 0.01). Significant reduction in secondary endogenous infections was found in the second year: seven versus 15 patients (P < 0.05). A total of 3,588 microbiological samples were processed. Neither Staphylococcus aureus with intermediate sensitivity to vancomycin (VISA) nor vancomycin-resistant enterococci (VRE) were detected.     

Removal of an unexpected tracheal foreign body after five months

Foreign body aspiration can produce serious pulmonary diseases. Timely diagnosis and appropriate treatment is important to prevent long-term complications in affected children. We report the case of a 15-month-old child with a 5-month history of regurgitation, vomiting, recurrent tracheobronchitis, and pneumonia. The diagnosis was gastroesophageal reflux. The laryngotracheal endoscopy revealed a rabbit vertebra partially obstructing the airway at the level of the cricoid cartilage. With a rigid bronchoscope and forceps equipped with a telescope, it was possible to disengage and extract the foreign body. Six months later endoscopic control revealed no residual alterations in the larynx and trachea.     

Systemic and organ dysfunction response during infusion of recombinant human activated protein C (rhAPC) in severe sepsis and septic shock

AIM: The aim of this study was the assessment of the efficacy of recombinant human activated protein C (rhAPC) in septic patients. METHODS: A continuous observational prospective study on ICU patients with severe sepsis and septic shock was carried out. Applying the inclusion criteria of a national trial on the use of rhAPC, 15 patients (12 males and 3 females) were enrolled, mean age was 65.9 (SD 9.6), APACHE II score was > or =25. The following variables were assessed on 7 time-points (T1-T7): overall SOFA score; organ-specific SOFA score; APACHE II score; PCR, APTT, INR, fibrinogen, platelet count. Wilcoxon's statistical test and Spearman's correlation test (rho coefficient) between the SOFA and APACHE II scores were used. Test results with a P value below 0.05 were deemed significant. RESULTS: A significant correlation was identified between the APACHE II and SOFA scores. No significant change was found in Friedman's test and the respiratory, haematological and hepatic SOFA score, whereas cardiovascular, renal and neurological SOFA scores showed a significant trend between the ranks at the 7 time-points (chi2=14; df=6; P=0.029). During rhAPC treatment Friedman's test showed significant changes of PCR values over the 7 time-points (chi2=19.2; df=6; P=0.02). Wilcoxon's test indicated a significant decrease in the values recorded during the T2-T6 period. On day 28, 12 of the 15 patients originally enrolled were still alive. Mortality rate was therefore 20% (CI 95%). CONCLUSIONS: RhAPC is the first biological agent approved for the treatment of severe sepsis and septic shock. Our experience is confined to patients with severe sepsis and septic shock, and some severity indexes showed a modulation of the inflammatory processes and haemostatic balance, 2 factors which play a key role in the evolution of sepsis and organ dysfunction.     

Intrauterine undernutrition in rats interferes with leukocyte migration, decreasing adhesion molecule expression in leukocytes and endothelial cells

Experimental and epidemiologic data have shown that malnutrition predisposes individuals to infections. Immune responses are compromised, particularly in undernourished children. Therefore, we investigated the migratory capacity of leukocytes, using the intravital microscopy technique, in male Wistar rats (8-9 wk of age) that were undernourished in utero after their dams were fed 50% less food than the amount consumed by control dams. The number of leukocytes rolling along the venular endothelium, sticking after stimulation with leukotriene B4, tumor necrosis factor-alpha (TNF-alpha) or zymosan-activated plasma, or migrating after TNF-alpha stimulation was significantly reduced in the undernourished rat offspring. Compared with nourished rat offspring, undernourished offspring had significantly reduced numbers of circulating leukocytes, higher blood pressure, and higher leukocyte rolling velocity (V(WBC)), as well as a higher ratio between V(WBC) and RBC velocity (V(RBC)). Endothelial P-selectin and intercellular adhesion molecule-1 (ICAM-1) expression, analyzed by immunohistochemistry, and basal leukocyte L-selectin expression, analyzed by flow cytometry, were significantly reduced in the undernourished rat offspring. Because the groups did not differ in leukocyte CD11/18 expression, endothelial expression of platelet-endothelial cell adhesion molecule-1, or venular blood flow velocity and, consequently, venular shear rate, we conclude that intrauterine undernutrition in rats reduces leukocyte migration, downregulates endothelial expression of P-selectin and ICAM-1, as well as leukocyte expression of L-selectin, while reducing leukocyte counts. The higher V(WBC) and V(WBC)/V(RBC) ratio may also play a role in this reduced leukocyte migration. Our data suggest that this phenomenon is involved in the increased predisposition to infections in undernourished subjects.