Rat brain type II 5'-iodothyronine deiodinase activity is extremely sensitive to stress

The effects of different kinds of acute stressor on thyroid hormone concentrations and deiodinase activities were investigated in four brain regions (frontal cortex, amygdala, hypothalamus, and cerebellum) and in the pituitaries and livers of adult male rats. Five groups of rats were killed after each of the following stressors: (a) an intraperitoneal injection of saline, (b) intragastric intubation, (c) and (d) two different forms of handling, being grasped as for intraperitoneal injection and being moved from one cage to another, and (e) a 2-h period spent in a slowly rotating drum. Two other groups were placed in the rotating drums for 10 and 19 h (sleep deprivation experiment), respectively. All stressors induced significant (in some cases up to 200%) increases in the activity of type II 5'-iodothyronine deiodinase, which catalyzes the deiodination of the prohormone L-thyroxine (T4) to the active metabolite 3,3',5-triiodo-L-thyronine (T3). As a consequence, the tissue concentrations of T4 fell, and those of T3 rose (sometimes by up to 300%). However, these changes were limited to selected areas of the brain that were specific for each stressor and were not seen in all brain regions investigated in any group. No clear-cut effects of stress were seen on the activities of the type III 5-iodothyronine deiodinase isoenzyme, which catalyzes the inactivation of T3, on liver or serum thyroid hormone concentrations or on liver of brain type I 5'-iodothyronine deiodinase activities. In summary, our results show that even mild and very brief stress can induce marked increases in T3 concentrations specifically in brain but not in liver or blood. Thus, contrary to common opinion, thyroid hormones may play an important physiological role in stress reactions, at least in tissues that contain type II 5'-iodothyronine deiodinase, such as brain and pituitary.     

Variability of resveratrol (3, 5, 4′-trihydroxystilbene) content in relation to the fermentation processes by Saccharomyces cerevisiae strains

The variability of the four monomeric forms of resveratrol (3, 5, 4'-trihydroxystilbene) caused by 14 strains of fermentative yeasts belonging to the Saccharomyces cerevisiae species in Cannonau grape musts during three different stages of fermentation was assessed by HPLC. During the process a decrease in the glucoside forms (cis and trans-#-D-glucopyranoside) was observed in all the musts independently of the yeast strain used. As regards the activity of the free forms (cis and trans-resveratrol), the greatest differences were found in the first two stages of fermentation when some strains appeared to cause an increase in either one or both of the free forms while others produced a decrease in the two compounds.     

Multiple Failure Accident Sequences for SEAFP Reactor

This paper summarizes several investigations on the identification of possible multiple failure accidents relevant in terms of consequences for the SEAFP reactor. Particularly, on those sequences of events that could induce a risk of radioactive materials bypass through the SEAFP confinement barriers. The analyses here reported are related to the Heat Transfer Systems of both reactor models 1 and 2. The work is carried out within the Safety and Environmental Assessment of Fusion Power—Long Term Programme (SEAL) 95/96. A set of specific initiating events (IEs) has been individuated, on the basis of the previous studies performed in the frame of the first SEAFP program. Basing on pre-existing analyses, each accident initiator has been discussed and several sequences have been described depending on the additional failures which could follow the initiator.     

Pyrazole-related nucleosides. 4. Synthesis and antitumor activity of some 1-tetrahydropyranyl-4-substituted pyrazoles

Continuing our studies on the structure-activity relationships of some pyrazole nucleosides (1a-h) structurally related to ribavirin, tiazofurin and selenazofurin, we describe here the synthesis and antitumor/antiviral/antimicrobial activity of a new series of 1-tetrahydropyranyl-4-substituted pyrazoles. In this study, the tetrahydropyranyl moiety (THP), designed as a mimic of the glycosidic portion of the parent compounds 1a-h, has led to a few derivatives with moderate cytotoxic activity against leukemia/lymphoma and solid tumor-derived cell lines (IC50 14-100 microM). The compounds obtained through substitution of the ribofuranosyl moiety by the THP moiety were still active, the free heterocyclic bases were devoid of any activity.     

The development of hyperventilation in patients with chronic heart failure and Cheyne-Strokes respiration: a possible role of chronic hypoxia

AIM: To analyze the relationship between daytime respiratory and cardiac function in patients with compensated chronic heart failure (CHF) with and without periodic breathing (PB) or Cheyne-Stokes respiration (CSR). PATIENTS: We studied 132 patients (female, 13%; mean age, 53+/-8 years; body mass index, 25.9+/-3.5 kg/m2; left ventricular ejection fraction <40%; 23% in New York Heart Association class I, 43% in class II, and 34% in class III-IV). METHODS: Measurement of pulmonary function and blood gases, hemodynamic evaluation, analysis of breathing profile, echocardiography, recording of ECG, beat-to-beat arterial oxygen saturation, and respiration during spontaneous breathing. RESULTS: Fifty-eight percent of patients showed PB or CSR. Patients with PB or CSR have greater cardiac function impairment. Mean values of lung volumes and PaO2 were similar in the three groups of patients considered. In contrast, patients with PB or CSR had an increased minute ventilation and reduced PaCO2 values. Interestingly, patients with PB or CSR had lower values of arterial content of O2 and systemic oxygen transport (SOT) than patients with a normal breathing pattern (SOT, 394+/-9.8, 347+/-9.6, 438+/-11 mL of O2/min/m2, respectively; analysis of variance p<0.001). Weak correlations were found among lung volumes, blood gases, and cardiac function parameters: ie, vital capacity was correlated inversely with pulmonary capillary wedge pressure (PCWP) (-0.25; p<0.05); PaCO2 with PCWP (r=0.26; p<0.05), lung-to-ear circulation time (LECT) (r=-0.4; p<0.05), SOT (r=-0.33; p<0.0001), and cardiac index (CI) (r=0.27; p=0.003). Multiple regression analyses showed that arterial PCO2 was significantly correlated with SOT, LECT, and CI (r=0.51; r2=0.26; p<0.000001); the correlation became stronger considering only CSR patients (r=0.64; r2=0.4; p<0.001). CONCLUSIONS: Our study shows that patients with daytime breathing disorders have chronic hypocapnia. A reduced SOT may be one of the stimuli determining increased minute ventilation in these patients.     

Application of time series spectral analysis theory: analysis of cardiovascular variability signals

The volume of the anteroventral periventricular nucleus (AVPv) of the rat hypothalamus is larger in females than in males. A preliminary study from this laboratory found that this sexual dimorphism develops between days 30 and 91. The present study was designed to confirm and extend these findings and to determine the role of endogenous gonadal steroids in the development of the AVPv postnatally. The results indicate that the sexual dimorphism in AVPv volume arises between days 30 and 40 and that the length of the nucleus becomes sexually dimorphic between days 60 and 80. Additionally, both AVPv volume and length increased between days 30 and 80 in females. Castration of male rats on the day of birth sex-reversed AVPv volume in adulthood and AVPv length was sex-reversed by castration of males 5 days after birth; ovariectomy of females at these ages had no effect on either parameter. Moreover, in both males and females, AVPv volume and length were unaffected by gonadectomy at later ages. That the AVPv appears to be influenced by testicular hormones neonatally, but changes structurally around the time of puberty in females, clearly challenges current concepts of sexual differentiation that limit the process to the early postnatal period.     

On the measurement of copper surface area by oxygen chemisorption

Due to the multiplicity of problems recently evidenced by the widely used N₂O decomposition technique, the oxygen chemisorption technique for the measurement of Cu surface area was updated and optimized. A standard procedure was defined, which allows to obtain reliable and reproducible data. In particular, no arbitrary assumption was made for the Cu/O chemisorption stoichiometry and for the degree of surface coverage. Conversely an experimental value of the average Cu/O surface ratio, including the degree of coverage, was determined by XRD–WAXS data. The value obtained (2.35) corresponds to a chemisorption stoichiometry Cu/O=2 and to about 15% unoccupied surface Cu atoms. The proposed technique has been successfully used for the characterization of several commercial low-temperature water gas shift catalysts (Cu-ZnO-Al₂O₃).     

Assessment of the microbiological safety of dried spices and herbs from production and retail premises in the United Kingdom

A study of dried spices and herbs from retail and production premises to determine the microbiological status of such products was undertaken in the UK during 2004. According to EC Recommendation 2004/24/EC and European Spice Association specifications, 96% of 2833 retail samples and 92% of 132 production batches were of satisfactory/acceptable quality. Salmonella spp. were detected in 1.5% and 1.1% of dried spices and herbs sampled at production and retail, respectively. Overall, 3.0% of herbs and spices contained high counts of Bacillus cereus (1%, ≥10⁵ cfu g⁻¹), Clostridium perfringens (0.4%, ≥10³ cfu g⁻¹) and/or Escherichia coli (2.1%, ≥10² cfu g⁻¹). Ninety percent of samples examined were recorded as being ‘ready-to-use’, 96% of which were of satisfactory/acceptable quality. The potential public health risk of using spices and herbs as an addition to ready-to-eat foods that potentially undergo no further processing is therefore highlighted in this study. Prevention of microbial contamination in dried herbs and spices lies in the application of good hygiene practices during growing, harvesting and processing from farm to fork, and effective decontamination. In addition, the importance of correct food handling practices and usage of herbs and spices by end users cannot be overemphasised.     

Cover Picture: Surfactant‐Mediated Generation of Iso‐Oriented Dense and Mesoporous Crystalline Metal‐Oxide Layers (Adv. Mater. 14/2006)

For certain metal oxides (e.g., MoO₃) ordered mesoporous films can be obtained with the nanocrystals in the pore walls being uniformly oriented with respect to the substrate by applying evaporation‐induced self‐assembly followed by heating. This surprisingly facile process, described by Smarsly and co‐workers on p. 1827, works on different polar substrates (glass, metals, etc.) for oxides with anisotropic unit cells, based on the interaction with surfactants during nucleation (“soft‐epitaxy”).