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Biomedical subjects

J Rubio

Publications and source records attributed to J Rubio.

At least 37 records · Page 2Linked to original sources
PubMed1995

Formation of 8-nitroguanine in DNA treated with peroxynitrite in vitro and its rapid removal from DNA by depurination.

Peroxynitrite is a strong oxidant formed by reaction of nitric oxide with superoxide in inflamed tissues. We have demonstrated that 8-nitroguanine is formed dose-dependently in calf thymus DNA incubated with low concentrations of peroxynitrite in vitro. 8-Nitroguanine in acid-hydrolyzed DNA was chemically reduced into 8-aminoguanine, which was analyzed using high performance liquid chromatography with electrochemical detection. Only peroxynitrite, but not nitrite, tetranitromethane nor NO-releasing compounds, formed 8-nitroguanine. Antioxidants and desferrioxamine inhibited the reaction. 8-Nitroguanine was depurinated from DNA incubated at pH 7.4, 37 degrees C (t1/2 = approximately 4 h). Peroxynitrite did not increase 8-oxoguanine levels in DNA.

Animals↗
PubMed1995

Formation of 8-nitroguanine by the reaction of guanine with peroxynitrite in vitro.

Nitric oxide and superoxide anion, both formed in inflamed tissues, react rapidly to form the peroxynitrite anion (ONOO-), a strong oxidant which can initiate reactions characteristic of hydroxyl radical (HO.), nitronium ion (NO2+) and nitrogen dioxide radical (NO2.). Peroxynitrite, therefore, may cause DNA or tissue damage, contributing to the multistage carcinogenesis process. We have studied reactions of various bases, nucleosides or deoxynucleosides with peroxynitrite in vitro. Guanine reacted rapidly with peroxynitrite under physiological conditions and formed several substances, two of which were yellow, a characteristic of nitro and nitroso compounds. On the basis of chromatographic and spectral evidence we identified the major compound (which accounts for approximately 80% of all compounds formed) as 8-nitroguanine. Its formation was maximal at approximately pH 8 and increased dose-dependently with peroxynitrite concentration, but was not dependent on guanine concentration. The presence of ferric ions, which has been shown to catalyse nitration of tyrosine, did not affect nitration of guanine. 8-Nitroguanine could act as a specific marker for DNA damage induced by peroxynitrite in inflamed tissues.

Carcinogens↗
PubMed1995

Chylothorax due to Mycobacterium tuberculosis.

Chylothorax in an adult is a rare cause of pleural effusion. Mycobacterium tuberculosis may cause chylous effusion, but usually in association with extensive intrapulmonary involvement. A case of chylothorax is presented in which M tuberculosis was isolated from the pleural fluid and was the only intrathoracic manifestation of tuberculosis.

Aged↗
PubMed1994

Pathology and ploidy in the prognosis of gastric cancer with no extranodal metastasis.

BACKGROUND: The prognostic relevance of morphology in advanced gastric cancer is well known. Data on tumor cell DNA content are still inadequate and contradictory. METHODS: Morphologic parameters and DNA ploidy were evaluated in 76 gastric cancer patients with no extranodal metastases (Stage I, 10 cases; Stage II, 20 cases; and Stage III, 46 cases), using formalin-fixed paraffin-embedded tissue. All cases were followed for at least 6 years after surgery or until death. RESULTS: Among the potential prognostic factors analyzed by Mantel-Cox and generalized Wilcoxon statistics, male sex (P = 0.02), cardiac location of neoplasia (P = 0.02), deeper infiltration of the gastric wall (P = 0.001), vascular neoplastic invasion (P = 0.006), metastatic lymph nodes (P = 0.001), pathologic stage (P = 0.0001), and aneuploidy (P = 0.01) were significantly associated with lower survival rate. Testing of all of the above-mentioned variables by the Cox stepwise multiple regression model disclosed that factors independently associated with survival were stage (P = 0.0001), ploidy (P = 0.0006), and vascular carcinomatous invasion (P = 0.01). CONCLUSIONS: In gastric cancer with no extranodal metastases, DNA ploidy was found to be the most significant prognostic parameter after pathologic stage.

Aged↗
PubMed1994

[Aortic pseudoaneurysm and acute myocardial infarct secondary to thoracic trauma].

Three cases of traumatic cardiovascular disease following chest trauma in males with no previous ischemic heart episodes are presented. One of them coursed with a combination of myocardial infarction and aortic pseudoaneurysm in an unusual location. The others coursed with and acute myocardial infarction and an aortic pseudoaneurysm, respectively. It is also underlined the utility of transthoracic and transesophageal echocardiography as well as a routine hemodynamic evaluation in this kind of patients.

Accidents, Traffic↗
PubMed1994

Echocardiographic features of the normofunctional Labcor-Santiago pericardial bioprosthesis.

Echocardiography was performed in 94 patients with a total of 99 normally functioning Labcor-Santiago bioprostheses, 62 in the aortic and 37 in the mitral position. The following variables were measured: peak and mean transvalvular velocities, peak and mean instantaneous pressure gradients as calculated from the modified Bernoulli equation, pressure half-time, cardiac index, stroke volume and effective orifice area (using continuity and Hatle equations). Regurgitation patterns were sought by transthoracic echocardiography (all valves) and, for selected mitral bioprostheses, by transesophageal echocardiography. Calculated mean aortic pressure gradient ranged from six to 10 mmHg and calculated effective aortic orifice area increased with ring diameter, with means of 1.27 cm2 for the 19 mm valve and 2.58 cm2 for the 27 mm valve. For mitral bioprostheses, mean pressure gradient ranged from 3.0 to 4.5 mmHg and calculated effective orifice area from 2.27 to 2.73 cm2. Only central regurgitation was observed. The Labcor-Santiago pericardial bioprostheses created little resistance to forward flow. In the small aortic root their hemodynamic performance was as good or better than that of other currently available devices. It is hoped that this new design will contribute increased in vivo mechanical durability.

Adult↗
PubMed1994

Endocarditis with pericardial bioprostheses: clinico-pathologic characteristics, immediate and long term prognosis.

Between 1977 and 1992, 30 consecutive episodes of infective endocarditis in 28 patients involving pericardial bioprostheses were diagnosed and treated in our hospital. Eleven (37%) were early pericardial valve endocarditis occurring in the first 60 days following valve surgery, and 19 (63%) were late endocarditis. In both the early and late groups, more aortic that mitral valves were affected (19/30). The most frequent pathogen in the early cases was staphylococcus, (S. epidermidis in five cases, S. aureus in one). The most frequent pathogen among late cases was streptococcus: (St. viridans in four, St. faecalis in two, St. bovis in one). In four cases (13%) no pathogen was isolated. Twelve patients received antibiotic treatment alone, six specific for the pathogen and other six only arbitrarily chosen regimen. All patients were cured in the former and all patients died in the latter group (four with negative blood cultures and two in whom identification of the pathogen was delayed-Proteus mirabillis in one case and Brucella mellitensis in the other). Valve replacement during the infective endocarditis episode was necessary in 18 cases, either because of failure of the antibiotic treatment or because of heart failure secondary to prosthetic malfunction. Peri-annular abscess was present in five cases. Surgical mortality was 22.2% (4/18). In all, 11 patients (39%) died during the active stage of infective endocarditis. The most frequent cause of death was heart failure (45.5%). All four patients with negative blood cultures died. The most advisable strategy for treating bacterial endocarditis of pericardial bioprostheses is a combination of antibiotic therapy and early surgery, especially in cases of staphylococcus endocarditis.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Bacterial Agents↗
PubMed1994

[Myocardial ischemia secondary to a bilateral coronary fistula with drainage into the pulmonary artery trunk].

A case of bilateral coronary artery fistula into main pulmonary artery which courses with crisis of angina and subepicardial ischaemic changes in anterolateral leads is presented. The interest of the case reported is based on the peculiar anatomy of the fistula; there is only an unique collector to the pulmonary artery for both fistula and they present a completely different way of emerging: an unique vessel from the right coronary artery and several vessels from the anterior descending coronary artery. Ligation of the fistula was performed successfully and postoperative course was uneventful.

Angina Pectoris↗