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Biomedical subjects

G Ragno

Publications and source records attributed to G Ragno.

47 records · Page 3Linked to original sources
PubMed1988

Determination of p-aminosalicylic acid and m-aminophenol by derivative UV-spectrophotometry.

A direct method for the simultaneous determination of p-aminosalicylic acid (PAS) and its major decomposition product, m-aminophenol (MAP), is described. The analysis is based on the use of derivative UV-spectrophotometry and is a rapid procedure which gives accurate and precise results. A simple purity test which utilizes the third derivative spectrum is also reported and compared with the USP XX spectrophotometric method for the estimation of MAP in PAS formulations.

Journal Article↗
PubMed1988

The 24-hour posttransfusion survival and lifespan of autologous baboon red cells treated with inositol hexaphosphate-polyethylene glycol or inositol hexaphosphate-adenosine triphosphate-polyethylene glycol to decrease oxygen affinity.

Baboon red cells were treated to reduce oxygen affinity by an osmotic-pulse procedure using dimethyl-sulfoxide. Inositol hexaphosphate (IHP) alone or IHP and adenosine triphosphate (ATP) were incorporated into the red cells in the presence of polyethylene glycol (PEG). The procedure produced variable increases in the red cell P50 value, i.e., the partial pressure of oxygen at which 50% of the hemoglobin was saturated. The effect of treatment of autologous baboon red cells on the 24-hour posttransfusion survival value and lifespan T50 value was measured using a double-label procedure. The data demonstrate that the increase in the P50 value of treated red cells was negatively correlated with the 24-hour posttransfusion survival value; the higher the P50 value, the poorer the 24-hour posttransfusion survival value. The 24-hour posttransfusion survival value for nontreated baboon red cells was 90% and the T50 value was 14 days. The IHP-ATP-PEG-treated red cells had significantly higher red cell ATP levels than did IHP-PEG-treated red cells. The 24-hour posttransfusion survival value was 68% for the IHP-ATP-PEG treated red cells and 52% for the IHP-PEG-treated red cells when the increase in P50 ranged from 10 to 20 mm Hg; the lifespan T50 value for both the IHP-ATP-PEG-treated red cells and the IHP-PEG-treated red cells was 15 days. Osmotic pulse treatment produced significant red cell injury manifested by the 24-hour posttransfusion survival value. However, modification of the RBC with IHP-PEG or IHP-ATP-PEG to decrease hemoglobin affinity for oxygen did not affect their lifespan.

Adenosine Triphosphate↗
PubMed1987

Hypothermia-induced reversible platelet dysfunction.

Baboons that were subjected to systemic hypothermia at 32 C had an arm skin temperature of 27.3 C and bleeding time of 5.8 minutes. With local warming of the arm skin to 34 C, the bleeding time was 2.4 minutes. In normothermic baboons with arm skin temperature of 34.6 C, the bleeding time was 3.1 minutes. Local cooling of the arm skin to 27.6 C produced a bleeding time of 6.9 minutes. Increasing the skin temperature of the arm in hypothermic baboons to 38.9 C and in normothermic baboons to 40.1 C reduced bleeding times to 2.1 and 2.3 minutes, respectively. In both hypothermic and normothermic baboons there was a negative and significant correlation between the bleeding time and the arm skin temperature and the thromboxane B2 level in the shed blood obtained at the template bleeding time site. There was a significant positive correlation between the thromboxane B2 level in the shed blood and the arm skin temperature. Both in-vivo and in-vitro studies have shown that the production of thromboxane B2 by platelets is temperature-dependent, and that a cooling of skin temperature produces a reversible platelet dysfunction. Data also suggest that when a hypothermic patient bleeds without surgical cause, skin and wound temperature should be restored to normal before the administration of blood products that are not only expensive but may also transmit disease.

Animals↗
PubMedDate not supplied

Photostabilization of 1,4-dihydropyridine antihypertensives by incorporation into beta-cyclodextrin and liposomes.

Inclusion compounds of eleven dihydropyridine drugs were formed and investigated for protection against photo-induced drug degradation. Formulations of cyclodextrins and liposomes were prepared and their photoprotective ability for the encapsulated drug was monitored. Drug photodegradation was spectrophotometrically followed during exposure of the formulations to light of a Xenon lamp. ICH guidelines for photostability testing were applied. A comparison with common pharmaceutical formulations revealed optimal protection for both formulations. The use of the liposome and cyclodextrin inclusion complexes resulted in a mean drug recovery of 77 and more then 90% respectively, after a light exposure until to 30 minutes with an intensity of 21 kJ x min(-1) m(-2). Lercanidipine and Manidipine only did not show a satisfactory increase of photostabilization in the studied supramolecular complexes, due to their low inclusion in both the systems.

Antihypertensive Agents↗
PubMedDate not supplied

[Reliability of the Karasek scale in the assessment of perceived occupational stress and gender-related differences in scores. The SEMM study].

In recent years more attention has been paid to the relationship between work organization and job stress and chronic-degenerative diseases. Aims of this report are the assessment of the reliability and internal consistency of the Karasek's Job Content Questionnaire-JCQ and to assess age-specific distributions of core JCQ scores between the gender groups. The study has been carried out in a large group of employees (n. 7871 subjects, 5270 women and 2601 men) of the Municipality of Milano in the years between 1992 and 1996. Decision Latitude (DL), Psychological Job Demand (PJD) and Social Support at Work (SSW) scores were calculated. Reliability of the JCQ was satisfactory, with Cronback's alpha suitable values for DL and SSW and acceptable for PJD. From the distribution of gender- and age-specific mean scores, women show reduced probabilities of developing a favorable career and of perceiving satisfactorily the support from colleagues and supervisors than men when they get older. This results suggest that the Karasek's JCQ is an effective toll to describe perceived job stress conditions in this Italian work setting.

Adult↗