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Biomedical subjects

N Romano

Publications and source records attributed to N Romano.

90 records · Page 5Linked to original sources
PubMedDate not supplied

Effect of an oxidative stress on methionine and S-adenosylmethionine metabolism in cultured bovine eye lens.

The sulphonium compound [Formula: see text] (AdoMet) plays a central role in many metabolic reactions of cellular metabolism, acting both as a propylamine donor in the biosynthesis of polyamines as well as a methyl donor in the transmethylation reactions. Moreover, AdoMet is a key intermediate of the transsulphuration pathway by which methionine is converted into cysteine, a precursor of glutathione. The aim of this study was to investigate the methionine and AdoMet metabolism in bovine lenses cultured in the presence of labelled methionine, upon treatment with H(2)O(2), as the experimental model for studying the molecular mechanisms responsible for the onset of senile cataract. The results reveal that one of the earliest changes following an oxidative stress is a severe impairment of protein synthesis. As far as the synthesis of AdoMet is concerned, a small but significant decrease in the conversion of labelled methionine into AdoMet occurs in treated lenses compared to the controls. In order to verify if the decreased AdoMet synthesis would lead in turn to alterations of methyl transfer reactions, we examined changes in the levels of various macromolecular methylations, such as protein methyl esterification and phospholipid methylation. The data clearly indicate that both the synthesis of AdoMet and the methyl transfer reactions could be significantly affected in eye lens upon an oxidative stress, suggesting that these alterations could be one of the biochemical events related to the ethiology of senile cataract. Finally, the question of whether or not H(2)O(2)-induced alterations of methionine and AdoMet metabolism could, in turn, affect some closely related metabolism, such as glutathione-associated reactions, is also discussed.

Journal Article↗
PubMedDate not supplied

Ontogeny of the thymus in a teleost fish, Cyprinus carpio L.: developing thymocytes in the epithelial microenvironment.

A monoclonal antibody, WCL9, specific for membrane molecules of a thymocyte subpopulation was used to detect these cells in situ during the ontogeny of thymus. Cryo-sections revealed WCL9+ cells in the rudiment of the thymus (day 4 post fertilization); thereafter, the positive cells were observed exclusively in the cortex from the first appearance of thymic regionalization (week 4 post fertilization) until adult age. Whole-mount immunostaining of the thymus with WCL9 revealed the three-dimensional structure of the cortex by specific staining. The presence and distribution of apoptotic cells during thymus development was studied by in situ end-labelling of fragmented DNA. From week 4 post fertilization onwards, apoptotic cells were more frequently detected in the cortex than medulla, suggesting a continuous selection of thymocytes in the cortex. Ultrastructural studies confirmed the presence of numerous cortical apoptotic cells inside macrophages. Electron microscopy provided evidence for the existence of epithelial heterogeneity in the thymus. During the ontogeny, the differentiation of epithelial cells was followed from the first weeks until the juvenile age. Cell types were classified on the basis of their localization and cytological characteristics as: i) limiting epithelial cells located in subcapsular, perivascular and peritrabecular zones; ii) reticular epithelial cells situated in medullary and cortical zones; iii) nurse-like cells at the border between the cortex and medulla, iiii) Hassall's body-like structures localized in the medulla. This study could suggest the occurrence of a wide range of lympho-epithelial interactions throughout thymocytes differentiation.

Animals↗
PubMedDate not supplied

Energy production in Ureaplasma urealyticum.

Ureaplasma urealyticum lacks the conventional mechanisms for adenosine 5-triphosphate (ATP) generation, such as glycolysis or arginine breakdown, present in other mycoplasmas. The possibility that ATP may be generated in these organisms through the formation of an ion gradient coupled to urea hydrolysis has been suggested by Masover and Hayflick (Ann NY Acad Sci 225:118-130, 1973). Our data have proved that ATP is produced when urea is added to resting ureaplasmal cells and its formation requires the concomitant activity of both cytoplasmic urease and membrane-bound ATPase and is drastically reduced by carbonylcyanide-m-chlorophenylhydrazine. Analysis of the optimal conditions for ATP synthesis in ureaplasmas indicates that this energetic process depends upon phosphate, urea, pH and ammonium ions in the reaction mixture. Particularly ammonium ions can interfere with the production of energy only when the starting pH is kept slightly basic. We have also shown that the changes in fluorescence intensity are directly related to the concentrations of the added urea and are inhibited by the presence of acetohydroxamic acid, carbonycyanide-m-chlorophenylhydrazine, and ammonium ions. It appears that urea hydrolysis can generate an electrical potential through NH4+ diffusion across the Ureaplasma membranes, but this diffusion is also dependent upon the external acidic pH of the reaction mixture.

Adenosine Triphosphate↗
PubMedDate not supplied

[Wiscott-Aldrich syndrome. Description of a case].

The Wiscott-Aldrich syndrome with the classical symptomatology (eczema, thrombocytopenia and susceptibility to infections) has been described in a 3-month-old child. The family history, together with the evidence of an immunological deficiency involving both thymus-dependent lymphocyte and immunoglobulin-antibody systems have given important clues to diagnosis. Impairment of immunoglobulin homoeostasis and its relevance to the assessment of heterozygotes is discussed.

Antibody Formation↗
PubMedDate not supplied

[Epidemiology of Cesarean section and birth surveillance].

The authors studied the incidence and the determinants of cesarean section in ASL Naples 4. In addition while they analysed the reliability and completeness of birth certificates in order to verify their accuracy for statistical and epidemiological purposes. The results show an increase of cesarean section higher than national mean (from 1997 to 2000: 44.5-54.9%), rarely justified by real risk conditions. 41.1% of vertex deliveries required cesarean section. The most frequent indications were repeated cesarean section (40.6%) and fetal problems (39.3%) in the multiparous; fetal dystocia (27.8%) and fetal distress (17.1%) in the primiparous. The quality of the compilation of the certificates was unsatisfactory for completeness and reliability. Indeed, 14.9% of 1997 birth certificates and more than 70% in the following years did not reach the epidemiological services of ASL; moreover, the comparison with clinical records proved that 46.9% of presentations resulted abnormal on clinical records were vertex on the birth certificates.

Adolescent↗
PubMedDate not supplied

[Tuberculin test: proposal for a pre-test risk assessment questionnaire and a standardized evaluation].

Relevance of latent infection in the epidemiology of tuberculosis (TB) is expected to increase in many developed countries. Indeed, many demographic, social and public health changes could contribute to the expansion of groups or communities at significantly higher risk than the general population for infection to Mycobacterium tuberculosis or progression from latent to active disease. Tuberculin skin testing (TB), the gold standard for diagnosis of M. tuberculosis infection, is imperfect and prone to false positive and negative results, unless strictly targeted and carefully standardized for reliable performance and interpretation. This paper proposes a pre-test risk assessment questionnaire and standardized criteria for evaluation of TB test according to international guidelines.

Humans↗
PubMedDate not supplied

[The influence of professional degree on the knowledge of HIV, HBV and HCV infections in dentistry practice].

The knowledge and preventive practices toward the risk of infection with HIV, HBV and HCV were evaluated in a sample of 254 dentists and odontostomatologies in Palermo, by answering to an anonymous questionnaire sent by mail. Overall, most of the participants showed a good knowledge of the transmission pattern of blood-borne viruses as well as good practice for personal hygiene (washing of hands, routine use of gloves, etc.). However 80.8% answered to recap needles after use and more than 40% have had at least one needle injury during the last year in their occupational setting. Moreover, nearly 24% of the interviewed declared to have not made vaccination against Hepatitis B virus infection. Statistical analysis showed a significant correlation between better knowledge, safer practice and different teaching training suggesting that odontostomatology degree might be more appropriate for a better training in preventive medicine for blood borne pathogens. Data also suggest the need of continuous worker education to reduce occupational blood exposures in dentistry.

Adult↗
PubMedDate not supplied

Effects of partial decerebration and hypophyseal allograft in the thymus of chicken embryos: thymostimulin localization and enzymatic activities.

Changes in chicken embryo thymus after partial decerebration (including the hypophysis) and hypophyseal allograft were investigated. Chicken embryos were partially decerebrated at 36-40 hr of incubation and on day 12 received a hypophyseal allograft from 18-day-old donor embryos. The embryonic thymuses were collected on day 18 and examined with histological methods, tested for the anti-thymostimulin-like immune-reaction, and for histoenzymatic activities and compared with normal and sham-operated embryos at the same age. After partial decerebration, the thymic cortical and medullary compartments diminished markedly in size. Anti-thymostimulin, succinic dehydrogenase and ATPase enzymatic activities tested, yielded negative reactions. In partially decerebrated hypophyseal allografted embryos, the same thymic compartments improved and anti-thymostimulin-like immune-reaction and enzymatic activities partially recovered. These findings confirmed the key role of hypophysis in thymic ontogenic development and provided new information in metabolic enzymatic pathways and synthesis of a thymostimulin-like substance in the thymus.

Animals↗