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Biomedical subjects

J Rubio

Publications and source records attributed to J Rubio.

At least 55 records · Page 3Linked to original sources
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↗
PubMed1993

Antimutagenicity of cyclohexanol towards 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone and N-nitrosodiethylamine in Salmonella typhimurium strain TA100.

The ability of cyclohexanol to inhibit the mutagenicity of tobacco-specific nitrosamine 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK) and of N-nitrosodiethylamine (NDEA) was tested on Salmonella typhimurium strain TA100. Cyclohexanol produced a dose-dependent decrease in the number of revertants induced by a single dose of NNK (24 mumoles) or NDEA (59 mumoles). Nevertheless, this inhibitory effect was not observed with other premutagenic agents such as benzo[a]pyrene and 2-aminoanthracene nor with direct mutagens such as ethyl methanesulfonate and methyl methanesulfonate. These results suggest that cyclohexanol interferes with the 'bioactivation' of the tested nitrosamines in a similar way that other alcohols such as ethanol or isopropanol interfere with N-nitro-sodimethylamine and NDEA metabolism.

Antimutagenic Agents↗
PubMed1993

Mutagenic activity of urban air samples and its modulation by chili extracts.

Different samples of ambient particulate organic matter were collected during the summer and winter of 1990 in Mexico City. After dichloromethane extraction, the samples were tested for mutagenicity with derivatives of Salmonella typhimurium possessing high activity of 'classical' nitroreductase (YG1021) or O-acetyltransferase (YG1024), and compared to the mutagenicity of the normal strain YG1020, and to that of a nitroreductase-deficient mutant TA98NR. The two enzyme-overproducing strains were more sensitive to the mutagenic effect of the extracts than the parent and deficient strains. The sensitivity order, i.e., YG1024 > YG1021 > YG1020 > TA98NR, emphasizes the usefulness of the new Salmonella strains in analyzing the mutagenicity of complex mixtures and suggests that some of the direct mutagenic compounds in the urban air samples are nitro-aromatics. Investigations were also conducted to analyze the effect of chili extract on the mutagenicity of an urban air sample. The extract itself showed moderate mutagenic activity and an additive effect was noted when both the chili and air extracts were present. On the other hand, the maximum volume of chili tested produced a decrease in the number of revertants without affecting the background lawn of bacterial growth. The same response was also observed when 1-nitropyrene, 1,6-dinitropyrene or 1,8-dinitropyrene was used as the genotoxic compound, although potentiation instead of addition occurred at low vegetable volumes. At the concentrations found in the chili extract, chlorophyllin and beta-carotene showed an antimutagenic effect against the nitro-aromatic compounds.

Air Pollution↗
PubMed1993

Pathology of the gastric antrum and body associated with Helicobacter pylori infection in non-ulcerous patients: is the bacterium a promoter of intestinal metaplasia?

A series of 115 consecutive, non-ulcerous, dyspeptic patients were examined for Helicobacter pylori (H. pylori) colonization in the gastric antral and/or body mucosa using Giemsa staining. Findings were correlated with the presence and degree of activity of superficial gastritis, deep gastritis, atrophic gastritis and with the presence of intestinal metaplasia. The prevalence of H. pylori positivity was 61.7%. In 59 of the 71 positive patients (83%), H. pylori was detected in the antrum or in both the antral and oxyntic mucosa. In the remaining 12 positive patients, H. pylori was detected only in the oxyntic mucosa nad in all these cases, the antrum showed intestinal metaplasia associated with atrophic gastritis (25%). In both antral and oxyntic mucosa, the activity of the gastritis was significantly correlated with H. pylori colonization. Linear logistic regression analysis showed that in patients with intestinal metaplasia the presence of H. pylori infection was significant in predicting the presence of more extensive intestinal metaplasia after adjusting for age. The prevalence of intestinal metaplasia types II and III was 65.5% in the H. pylori positive and 25% in the H. pylori negative patients. The antral mucosa is thought to be the elective site for H. pylori related histological lesions. At a later stage, H. pylori can be detected only in the oxyntic area while the antral mucosa shows extensive metaplastic or atrophic lesions. We would suggest that H. pylori plays a promotional role in the morphogenesis of intestinal metaplasia.

Adolescent↗
PubMed1993

Doppler echocardiographic evaluation of the Bioflo pericardial bioprosthesis.

The Bioflo pericardial bioprosthesis was introduced to improve the durability of previous pericardial bioprostheses by means of a protective sheath of bovine pericardium around the stent. It has since been withdrawn from the market. Before its withdrawal, we studied 19 patients with mitral Bioflo valves (three of 25 mm, seven of 27 mm, eight of 29 mm, one of 31 mm) and 21 patients with aortic Bioflo valves (eight of 19 mm, nine of 21 mm, four of 23 mm) between two weeks and six months postoperatively, at which time all were in NYHA functional classes I or II. Standard Doppler echocardiographic measurements were taken to determine the effective orifice area of all valves, the peak and mean diastolic gradients across the mitral valves, and the peak and mean systolic gradients across the aortic valves. The smaller Bioflo valves performed poorly both in absolute terms and in comparison with other valves, presumably due to a reduction in the effective orifice area by the protective sheath. This finding should be borne in mind by the designers of future pericardial bioprostheses.

Adult↗