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The dynamics of the radical-radical reaction O((3)P) + C(3)H(5) has been investigated by means of the crossed molecular beam technique with mass spectrometric detection at a collision energy of 73.0 kJ mol(-1); the reaction mechanism of the H-displacement channel has been elucidated, while experimental evidence of the occurrence of one or more C-C bond-breaking channels at this collision energy has been obtained.

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The authors present an environmental microbiological monitoring programme carried out over a period of 15 months in 16 operating theatres performing specific types of surgery. The levels of microbial contamination of the air and of four of the most representative surfaces of the clean area were determined at 3 different times for each theatre, both before and during surgery. For the air assessment, the results obtained with three different samplers, Sed-3 Unit, SAS and RCS, were compared. The results were on the whole acceptable, but some poor conditions were detected during the theatres in use, especially in general surgery theatres; in some of these the floors showed levels of contamination consistently exceeding the reference limits. As the monitoring programme proceeded, the microbiological quality of the air and of the surfaces in the theatres notably improved. The three air samplers showed different conditions expressed with units of measure not always readily comparable. For active samplers, the bacterial load determined by RCS, although less variable, were always higher (even 2-3 fold) than those obtained with the SAS. Passive sampling takes longer but determines the real risk of infection for the patients; contemporary determination of the fall-out and the CFU/m3 helps to identify the occupational risks. Since the limit values established by the ISPESL guidelines for the operating theatres have been defined only for active samplers, there is urgent need for more exhaustive national guidelines to define similar values also for passive sampling. The Authors conclude stressing the importance of promoting continuing information-education programmes to heighten the awareness of all those involved in operating theatre activities.

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To assess the relative reactivity of the spin-orbit excited state of atomic Cl with molecular hydrogen, we have measured differential cross sections using an atomic Cl beam with a known concentration of the ground and excited spin-orbit states. These are compared with the first determination of the cross sections from quantum mechanical scattering calculations on a set of coupled ab initio potential energy surfaces. The comparison suggests that these surfaces may underestimate the degree of rotational excitation of the HCl products and that the excited spin-orbit state plays a minor role in the reaction.

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In this paper the authors analyse the international bibliography about clinic tests on hyaluronic acid and Nerve Growth Factor at ocular level. This study was performed on request of a private oculistic clinic in the centre of Rome about the clinic test of the drugs mentioned above. Therefore, this paper is a joint work of Public Health physicians and oculists.

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Authors in the present contribute illustrate the tuberculosis disease in all aspects, the infection, the disease in active phase and in the resistant phase, the law, the prevention and the professional risk in exposed subject, and to consider the epidemiological aspect. Authors hope a coordinate approach between the different figure involved in the therapy and prevention of tuberculosis disease.

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The aim of the study was to identify the research priorities and strategies in Occupational Safety and Health (OSH) in Italy with a high degree of consensus. Based on the Delphi technique, a two-phase questionnaire was sent to experts at Universities, Local Health Units (ASLs) and Trade Unions. In the first phase, experts were requested to indicate three research topics in the OSH sector. A total of 27 topics for both universities and ASLs and 18 topics for Trade Unions were identified. In the second phase, experts were requested to assign a score from one (low relevance) to five (high relevance) to each topic previously identified. On the basis of a mean score reported for each topic, two ranked lists of priorities, one referred to universities and ASLs the other referred to Trade Unions, were formulated. The highest priority identified by universities and ASLs was occupational carcinogenesis, followed by quality in occupational medicine. Workers' information, education and participation was also identified with a high degree of priority. For Trade Unions, occupational cancers as well as training, information, participation and prevention awareness had the highest priority. Trade Unions also identify small-industries and occupational accidents as topics with high priority for research development. This study allowed a high degree of consensus to be reached regarding the research priorities in the OSH sector in Italy. Differences in the topics identified, or regarding the mean score of topics commonly identified, were related to the origin of the expert recruited to this study (University, ASLs or Trade Unions) and, for universities and ASLs, to the geographical area. In the authors' opinion, the full transfer of existing scientific data to occupational health practice and the harmonization of the priorities identified by this investigation are crucial if the research needs in the OSH sector in Italy are to be met.

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The dynamics of some elementary reactions of N(2D), C(3P,1D) and CN(X2 sigma +) of importance in combustion have been investigated by using the crossed molecular beam scattering method with mass spectrometric detection. The novel capability of producing intense, continuous beams of the radical reagents by a radio-frequency discharge beam source was exploited. From angular and velocity distribution measurements obtained in the laboratory frame, primary reaction products have been identified and their angular and translational energy distributions in the center-of-mass system, as well as branching ratios, have been derived. The dominant N/H exchange channel has been examined in the reaction N(2D) + CH4, which is found to lead to H + CH2NH (methylenimine) and H + CH3N (methylnitrene); no H2 elimination is observed. In the reaction N(2D) + H2O the N/H exchange channel has been found to occur via two competing pathways leading to HNO + H and HON + H, while formation of NO + H2 is negligible. Formation of H + H2CCCH (propargyl) is the dominant pathway, at low collision energy (Ec), of the C(3P) + C2H4 reaction, while at high Ec formation of the less stable C3H3 isomers (cyclopropenyl and/or propyn-1-yl) also occurs; the H2 elimination channel is negligible. The H elimination channel has also been found to be the dominant pathway in the C(3P,1D) + CH3CCH reaction leading to C4H3 isomers and, again, no H2 elimination has been observed to occur. In contrast, both H and H2 elimination, leading in comparable ratio to C3H + H and C3(X1 sigma g+) + H2(X1 sigma g+), respectively, have been observed in the reaction C(3P) + C2H2(X1 sigma g+). The occurrence of the spin-forbidden molecular pathway in this reaction, never detected before, has been rationalized by invoking the occurrence of intersystem crossing between triplet and singlet manifolds of the C3H2 potential energy surfaces. The reaction CN(X2 sigma +) + C2H2 has been found to lead to internally excited HCCCN (cyanoacetylene) + H. For all the reactions the dynamics have been discussed in the light of recent theoretical calculations on the relevant potential energy surfaces. Previous, lower resolution studies on C and CN reactions carried out using pulsed beams are noted. Finally, throughout the paper the relevance of these results to combustion chemistry is considered.

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The time course of changes in mitochondrial energy metabolism during liver regeneration, following partial hepatectomy, is analyzed. For 24 h after surgical operation, a lag phase in the time course of the growth of liver is observed. In this period mitochondria showed a decrease of: (1) the respiratory control index; (2) the rate of oxidative phosphorylation; (3) the amount of immunodetected beta-F1 and F01-PVP subunits of F0F1-ATP synthase. No decrease, but instead a small increase in the content of mRNA for beta-F1 was observed in this phase. After this lag phase the growth of liver started, the content of mRNA for beta F1, as well as the level of immunodetected mitochondrial beta-F1 and F01-PVP subunits, increased and oxidative phosphorylation recovered. Analysis of the relative beta F1 protein/mRNA ratio indicates a decrease of beta F1 translational efficiency which remained low up to 72 h after partial hepatectomy and reached the same ratio of control at 96 h. It is concluded that the regenerating capability of rat liver is correlated with the efficiency of oxidative phosphorylation.

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Earlier studies by Rouslin and coworkers showed that, during myocardial ischemia in slow heart-rate species which include rabbits and all larger mammals examined including humans, there is an IF1-mediated inhibition of the mitochondrial ATPase due to an increase in the amount of IF1 bound to the ATPase (Rouslin, W., and Pullman, M.E., J. Mol. Cell. Cardiol. 19,661-668, 1987). Earlier work by Guerrieri and colleagues demonstrated that IF1 binding to bovine heart ESMP was accompanied by parallel decreases in ATPase activity and in passive proton conduction (Guerrieri, F., et al., FEBS Lett. 213, 67-72, 1987). In the present study rabbit was used as the slow heart-rate species and rat as the fast heart-rate species. Rat is a fast heart-rate species that contains too little IF1 to down regulate the ATPase activity present. Mitochondria were prepared from control and ischemic hearts and ESMP were made from aliquots by sonication at pH 8.0 with 2 mM EDTA. Oligomycin-sensitive ATPase activity and IF1 content were measured in SMP prepared from the control and ischemic mitochondrial samples. After identical incubation procedures, oligomycin-sensitive ATPase activity, oligomycin-sensitive proton conductivity, and IF1 content were also measured in ESMP samples. The study was undertaken to corroborate further what appear to be fundamental differences in ATPase regulation between slow and fast heart-rate mammalian hearts evident during total myocardial ischemia. Thus, passive proton conductivity was used as an independent measure of these regulatory differences. The results show that, consistent with the low IF1 content of rat heart cardiac muscle mitochondria, control rat heart ESMP exhibit approximately twice as much passive proton conductivity as control rabbit heart ESMP regardless of the pH of the incubation and assay. Moreover, while total ischemia caused an increase in IF1 binding and a commensurate decrease in passive proton conductivity in rabbit heart ESMP regardless of pH, neither IF1 content nor proton conductivity changed significantly in rat heart ESMP as a result of ischemia.

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The effect of aging on rat liver regeneration and on the FoF1-ATP synthase complex of isolated liver mitochondria was followed after partial (70%) hepatectomy. ATP hydrolase activity in submitochondrial particles prepared from regenerating liver was first depressed; the time needed to reach the lowest activity was age dependent. This decrease was accompanied by parallel decrease of i) the respiratory rate of succinate supplemented mitochondria in state III; ii) the respiratory control index; iii) the rate of synthesis of ATP in succinate supplemented submitochondrial particles. This first phase of liver regeneration, characterized at all ages by a lag phase in the growth, was followed by a second phase in which the tissue mass was restored and the enzyme activities normalized. Immunoblot analysis showed that the changes in the catalytic activities of the FoF1-ATP synthase observed during liver regeneration were accompanied by parallel changes in the amount of subunits of both the catalytic (F1) and the membrane (Fo) sector of the complex.

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The influence of aging on mitochondrial energy metabolism of rat liver and rat heart has been studied by analysis of (i) respiratory rate of succinate-supplemented mitochondria in state III (coupled state in the presence of ADP + Pi); (ii) the rate of synthesis of ATP in succinate-supplemented mitochondria; (iii) the ATP hydrolase activity of sonicated submitochondrial particles. The results indicate a decrease of the F(0)F(1)-ATP synthase activity in mitochondria isolated from both organs of aged (24-month-old) as compared to young (3-month-old) rats which was accompanied by a decrease of immunodetected amount of the beta-F(1) (subunit of the catalytic F(1) sector of F(0)F(1)-ATP synthase). These effects were more evident in heart than in liver mitochondria. Analysis of the mitochondrial content of glutathione (GSH), an essential intracellular antioxidant agent, shows a decrease in mitochondria of both tissues of aged animals. Exposure of submitochondrial particles to free radicals, produced either by (60)Co or by respirtory chain (in presence of the inhibitor antimycin A) mimicked the alterations of F(0)F(1) ATP synthase obsreved in submitochondrial particles of aged rats. The possible relationship between aging process, free radical production and alteration of mitochondrial oxidative phosphorylation is discussed.

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We have studied the functional and molecular changes of mitochondrial FoF1 ATP synthase of cardiac muscle during aging. ATP hydrolase activity was lower in sonic submitochondrial particles prepared from hearts of senescent rats (24 months) than in those prepared from hearts of adult rats (12 months). Oligomycin-sensitive proton conduction of cardiac submitochondrial particles was greater in senescent rats than in adult rats. The beta subunit of F1, detected immunologically in submitochondrial particles, was less in senescent rats than in adult rats. Exposure of cardiac submitochondrial particles from adult rats to free radicals, generated by 60Co, resulted in inactivation of ATP hydrolase activity and a decreased content of F1. The structural and functional alterations of mitochondrial FoF1 ATP synthase during aging may be expected to affect energy metabolism, and our results suggest that they could originate from the action of free radicals generated in the inner mitochondrial membrane.

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In this paper we report observations on kinetic and structural characteristics of mitochondrial ATP synthase of rat-heart after subcutaneous injection of isoproterenol. The results obtained indicate: a decrease of respiratory rate either in absence (state 4) or in presence (state 3) of oxidative phosphorylation; decrease of respiratory control ratio; decrease of ATP hydrolase activity in sonic submitochondrial particles; decrease of relative content of the catalytic subunit F1 with respect to the membrane sector F0. The data obtained are in favour of the hypothesis that isoproterenol causes structural and functional alterations of mitochondrial ATP synthase.

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A study is presented on the role of F0 and F1 subunits in oligomycin-sensitive H+ conduction and energy transfer reactions of bovine heart mitochondrial F0F1 H(+)-ATP synthase. Mild treatment with azodicarboxylic acid bis(dimethylamide) (diamide) enhanced oligomycin-sensitive H+ conduction in submitochondrial particles containing F1 attached to F0. This effect was associated with stimulation of the ATPase activity, with no effect on its inhibition by oligomycin, and depression of the 32Pi-ATP exchange. The stimulatory effect of diamide on H+ conduction decreased in particles from which F1 subunits were partially removed by urea. The stimulatory effect exerted by diamide in the submitochondrial particles with F1 attached to F0 was directly correlated with a decrease of the original electrophoretic bands of a subunit of F0 (F0I-PVP protein) and the gamma subunit of F1, with corresponding formation of their cross-linking product. In F0 liposomes, devoid of gamma subunit, diamide failed to stimulate H+ conduction and to cause disappearance of F0I-PVP protein, unless purified gamma subunit was added back. The addition to F0 liposomes of gamma subunit, but not that of alpha and beta subunits, caused per se inhibition of H+ conduction. It is concluded that F0I-PVP and gamma subunits are directly involved in the gate of the F0F1 H(+)-ATP synthase. Data are also presented indicating contribution to the gate of oligomycin-sensitivity conferral protein and of another protein subunit of F0, F6.

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The age dependence of ATP hydrolase activity and oligomycin sensitive passive proton conduction in sonicated submitochondrial particles of rat brain and rat heart has been investigated. The results show an increase of Vmax of the ATP hydrolase activity and decrease of oligomycin sensitive passive proton conduction with increase of the age of rats from 3 to 6 months. Decrease of ATPase activity and increase of oligomycin sensitive proton conduction occur with further aging to 24 months. Immunoblot analysis shows that both the F(1) and F(0) contents of mitochondria vary with the age of rats, the former exhibiting relatively larger changes.

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Proteolytic digestion of F1-depleted submitochondrial particles (USMP), reconstitution with isolated subunits and titration with inhibitors show that the nuclear-encoded PVP protein, previously identified as an intrinsic component of bovine heart F0 (F01) (Zanotti, F. et al. (1988) FEBS Lett. 237, 9-14), is critically involved in maintaining the proper H+ translocating configuration of this sector and its correct binding to the F1 catalytic moiety. Trypsin digestion of USMP, under conditions leading to cleavage of the carboxyl region of the PVP protein and partial inhibition of transmembrane H+ translocation, results in general loss of sensitivity of this process to F0 inhibitors. This is restored by addition of the isolated PVP protein. Trypsin digestion of USMP causes also loss of oligomycin sensitivity of the catalytic activity of membrane reconstituted soluble F1, which can be restored by the combined addition of PVP and OSCP, or PVP and F6. Amino acid sequence analysis shows that, in USMP, modification by [14C] N,N'-dicyclohexylcarbodiimide of subunit c of F0 induces the formation of a dimer of this protein, which retains the 14C-labelled group. Chemical modification of cysteine-64 of subunit c results in inhibition of H+ conduction by F0. The results indicate that proton conduction in mitochondrial F0 depends on interaction of subunit c with the PVP protein.

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The inhibition of membrane ATPase from the marine alkalotolerant bacterium Vibrio alginolyticus by DCCD, triphenyltin and venturicidin was studied. DCCD proved to be an irreversible inhibitor, while venturicidin and triphenyltin produced a reversible inhibitory effect. The DCCD-binding proteolipid was identified in the membrane preparations. The effect of the inhibitors on ATPase activity and ATP-dependent Na(+)-transport in V. alginolyticus subcellular vesicles is discussed.

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