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Biomedical subjects

F Fernandes

Publications and source records attributed to F Fernandes.

At least 37 records · Page 2Linked to original sources
PubMed1997

Synergic activity of vancomycin-quinupristin/dalfopristin combination against Enterococcus faecium.

Clinical specimens were cultured, and the strains identified by the Vitek system as Enterococcus faecium were characterized by their DNA. The MIC vancomycin, quinupristin/dalfopristin and teicoplanin for each isolate was determined. Ten vancomycin-sensitive and ten vancomycin-resistant strains of E. faecium were tested. Quinupristin/dalfopristin at 0.25 x MIC and vancomycin at 0.5 x MIC separately as well as in combination were added to Trypticase Soy Broth tubes inoculated with a 24 h culture. The results obtained by determining cfu at 2, 4, 8, 12 and 24 h indicated that the combination of subinhibitory concentrations of quinupristin/dalfopristin plus vancomycin produced after 24 h, in vancomycin-resistant strains, a consistent degree of synergy. Synergy was observed up to only 12 h when similar combinations were employed for vancomycin-sensitive strains. Vancomycin-sensitive strains tended to be slightly less susceptible to quinupristin/dalfopristin than vancomycin-resistant strains.

Colony Count, Microbial↗
PubMed1997

[Radiological findings in endomyocardial fibrosis].

PURPOSE: To determine through conventional radiology the type of ventricular involvement in endomyocardial fibrosis (EMF). METHODS: We analyzed 56 cases with EMF confirmed by angiocardiography and 9 by postmortem study, aged between 16 and 56 years (mean 32); there were 42 females. Only one radiologist analyzed X-rays without any knowledge of the cineangiography findings. RESULTS: The right side of the heart was primarily involved in 9 patients and the cardiac silhouette was characteristically globular and had oligemic pulmonary fields (66.66%). The cardiothoracic ratio was 0.62 +/- 0.11. Out of 9 patients, 8 were female. The left side of the heart was established as being primarily involved in 11 cases and simulated rheumatic mitral disease. The cardiothoracic ratio was 0.51 +/- 0.09 and there were increased pulmonary fields in 63.6%. The biventricular disease occurred in 36 cases. There were radiologic findings of right and left side. The cardiothoracic ratio was 0.63 +/- 0.06 and there was oligemic pulmonary fields in 38.8%, increased pulmonary fields in 33.3% and was normal in 27.7%. There were 4:1 females. CONCLUSION: The radiological study is fundamental in the initial diagnosis of EMF. The type of involvement could be done in 66.07% of all cases by chest X-ray.

Adolescent↗
PubMed1996

Noradrenergic transmission in the tail artery of hypertensive rats transgenic for the mouse renin gene Ren-2.

1. The aim of the present study was to analyse the noradrenergic transmission in the tail artery of hypertensive rats transgenic for the mouse renin gene Ren-2 (TGR) in comparison with its control, the Sprague-Dawley (SD) rat. 2. Electrical field stimulation (EFS) of vascular segments produced frequency-dependent vasoconstrictions that were significantly greater in TGR arteries. 3. These contractions were abolished by tetrodotoxin (0.1 microM). Phentolamine (50 nM) and prazosin (1 - 10 nM) produced an inhibition of these responses that was significantly greater in SD arteries, whereas that produced by yohimbine (0.5-1 microM) was higher in TGR arteries. In both strains, propranolol (1 microM) potentiated the responses to EFS, and this increase was observed at lower frequencies in TGR arteries. 4. The EFS-evoked [3H]-noradrenaline (NA) release was significantly greater in TGR than in SD rats. However, NA (10 nM-10 microM) reduced and yohimbine and phentolamine (10 nM-10 microM) increased the tritium outflow to a similar degree in both strains. 5. Exogenous NA also induced greater vasoconstriction in TGR arteries. 6. These results suggest the existence in TGR tail artery of an increase in: (a) NA-release and alpha 2-adrenoceptor-mediated contractions, which could contribute to the elevated blood pressure in these rats; and (b) beta-adrenoceptor-mediated vasodilatations, which may be a mechanism to counteract high blood pressure.

Animals↗
PubMed1995

RP 59500 postantibiotic effect defined by bacterial ultrastructure.

Staphylococcus aureus was exposed to 0.3 microgram/ml RP 59500, an injectable streptogramin, 0.75 minimum inhibitory concentration (MIC) for six hours, washed, resuspended in fresh medium and incubated for ten hours. The postantibiotic effect (PAE) was determined by growth kinetics and by bacterial ultrastructure. The PAE was eight hours when determined by changes in the cell diameters and three hours when determined by the count of colony forming units (CFU).

Colony Count, Microbial↗
PubMed1993

Heterogeneity of ANCA sera showing atypical, peripheral and classical cytoplasmic immunofluorescence patterns.

Atypical (A) ANCA immunofluorescence (IF) patterns have been described in several disease groups. We have previously reported a distinct cytoplasmic A-ANCA in 7-10% of patients with SLE and/or RA. Here, we show that these rheumatic disease associated A-ANCAs are best identified using U937 cells as substrate and that they do not target either a serine proteinase or a peroxidase. Furthermore, these sera immunoprecipitate a 40 kDa or a 42 kDa band using in vivo 35S-amino acid labelled HL60 or U937 cell extracts, respectively. Although these bands are the only one seen with pure A-ANCA sera, they can also be found in addition to the expected bands of PR3 or MPO in up to 30% of bona fide C- or P-ANCA sera. These data confirm and extend our previous observations. They also suggest that target heterogeneity of ANCA antibodies is frequent. Care should thus be taken in interpreting in a cause and effect relationship, an IF pattern or a biological effect produced by a serum with ill documented monospecificity. The exact nature and significance of this (these) new antigen(s) have yet to be clarified.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1993

The role of transesophageal echocardiography in identifying anomalous coronary arteries.

BACKGROUND: The study objective was to evaluate the role of transesophageal echocardiography in identifying the origin of anomalous coronary arteries and confirming their course in relation to the great vessels. The diagnosis of coronary anomalies is made by angiography. The anomalous left main artery with a course between the pulmonary artery and the aorta has been associated with myocardial infarction and sudden death. The course of these anomalous coronary arteries is difficult to demonstrate by angiography alone. METHODS AND RESULTS: Nine patients with angiographically confirmed anomalous coronary arteries were studied by transesophageal echocardiography with color flow Doppler. The abnormal origin of the anomalous coronary arteries was confirmed by transesophageal echocardiography in all nine patients. In four patients, the left main coronary artery originated from the right sinus of Valsalva. In all of these patients, transesophageal echocardiography demonstrated the course of the anomalous left main coronary artery between the aorta and pulmonary artery better than angiography. Other anomalies that were visualized included two patients with origin of the right coronary arteries from the left aortic sinus, one patient with origin of the left anterior descending from the right sinus, one patient with origin of circumflex from the right sinus, and one patient with origin of the left main coronary artery from the pulmonary artery. CONCLUSIONS: Transesophageal echocardiography is a useful noninvasive test for diagnosing anomalous origin of the coronary arteries. Furthermore, it is a valuable adjunct to angiography in demonstrating the abnormal course of the left main coronary artery interposed between the aorta and the pulmonary artery, a potentially life-threatening entity.

Aged↗
PubMed1992

Effect of neuropeptide Y on adrenergic and non-adrenergic, non-cholinergic responses in the rat anococcygeus muscle.

1. The effects of neuropeptide Y (NPY) were examined on adrenergic and non-adrenergic, non-cholinergic (NANC) neurotransmission in the rat anococcygeus muscle. 2. NPY (0.1-0.3 microM) greatly potentiated the contractile responses induced by field stimulation. Prazosin (0.1 microM) completely abolished the stimulation-induced responses either in the absence or presence of NPY. 3. NPY (0.1-0.3 microM) enhanced only the contractile responses to low doses of noradrenaline (NA, 0.003-0.01 microM). Responses to tyramine were unaffected by the same concentrations of NPY. 4. In superfused anococcygeus, previously loaded with [3H]-NA, NPY (0.1-0.3 microM) failed to modify the basal, as well as the stimulation-evoked, release of tritium at 2 and 4 Hz. 5. NANC relaxations induced by electrical stimulation were significantly reduced, in a concentration-related manner, by 0.1-0.3 microM NPY. 6. L-NG-nitro-arginine (L-NOARG, 30 microM) enhanced the stimulation (0.25-1 Hz)-induced motor responses. In the presence of L-NOARG (30 microM), NPY (0.1 microM) did not modify the motor responses induced by field stimulation (0.25-0.5 Hz). L-Arginine did not reverse the NPY-induced potentiation of stimulation-induced motor responses. 7. The relaxations of anococcygeus muscle induced by sodium nitroprusside (SNP, 0.01-0.3 microM) were diminished by NPY (0.1-0.3 microM). 8. Our study suggests that NPY, at concentrations devoid of contractile effect, potentiates the motor responses of rat anococcygeus muscle as a consequence, at least in part, of the inhibition of NANC relaxing responses by a different mechanism from L-NOARG.

Animals↗
PubMed1990

[The use of Holter electrocardiography in permanent pacemaker users].

The authors selected 37 permanent pacemaker patients followed for eleven successive months, with symptomatology eventually related to the pacing system. An Holter ambulatory monitorization was performed to all of them during 24 hours. Twenty one had single chamber systems and the others double chamber. Twelve malfunctions were found in ten patients. Six due to "undersensing", 4 related to "oversensing", and 2 from loss of capture. Two patients had tachycardia pacemaker mediated. An inadequate mode of pacing was found in other two cases. Fifteen rhythm disturbances not related to the pacemaker systems were registered in thirteen patients: supra-ventricular in 9; ventricular greater than or equal to 3 degree of lown in 5; and 2nd degree A.V.B. Mobitz type I in one case. Four patients were submitted to surgical intervention in order to modify the mode of pacing. It was also necessary to reprogram ten patients. The Holter Ambulatory Electrocardiography revealed to be an important diagnostic method for the detection of intermittent malfunction of pacing systems. The occasional changes of cardiac rhythm not linked with pacing were also revealed.

Adult↗
PubMed1990

[Atrial pacing in the evaluation of coronary disease].

In order to assess the value of atrial pacing in the diagnosis of myocardial ischemia, 23 patients (mean age 53 +/- 8 years), submitted to coronary angiography, were studied. Atrial Pacing at incremental frequencies was performed until the appearance of electrocardiographic changes (ST segment depression) and/or typical anginal pain. The highest frequency of stimulation was 160/min. The test was negative in four of five patients (80%) without significant obstructive coronary artery disease. Atrial pacing test was positive in 17 of 18 patients (94%) with abnormal angiography. The authors concluded that clinical and ECG abnormalities induced by atrial pacing seems to be correct indicators for the diagnosis of myocardial ischemia. This test can be an useful alternative in patients unable to perform a conclusive stress test.

Cardiac Pacing, Artificial↗
PubMed1990

[Atrial pacing and the exercise test in the evaluation of coronary disease. A comparative study].

OBJECTIVE: to compare the relative value of Atrial Pacing and Exercise Electrocardiography in the diagnosis of Myocardial Ischaemia. DESIGN: prospective study in patients referred for coronary cineangiography. SETTING: Cineangiography and Ergonometry Departments of Cardiology Service. Santa Maria Hospital. PATIENTS: 16 patients (mean age 52.4 +/- 6.3), 13 males and 3 females. All were submitted to Atrial Pacing, Exercise Test and Coronariography. RESULTS: both tests were concordant in all cases but one, with negative Atrial Pacing, positive Exercise Test and negative Coronariography. CONCLUSIONS: Atrial Pacing compares favourably with Exercise Test in the diagnosis of Coronary Ischaemic Disease. It may constitute a valid alternative in patients unable to perform a conclusive Exercise Test.

Cardiac Pacing, Artificial↗
PubMed1987

A rapid method for the evaluation of new antituberculous agents.

Fifty-one new synthetic compounds belonging to four different series, namely (1a) substituted aryl-4-(substituted phenyl) succinimide; (1b) N-(substituted methyl)-4-(heterocyclic) succinimide; (2) heterocyclic 4-(5'-nitro-2-furyl) thiazoles; (3) substituted aryl-4-(3', 4'-dihydroxy phenyl) thiazoles, and (4) phenyl-N,N-1,2,3-bis-methoxy carbonyl guanidines were screened for antituberculous activity using a conventional broth dilution test (BDT) and a liquid scintillation radiometric method (LSRM). Eight compounds showed in vitro activity. LSRM showed 100% agreement with BDT. LSRM is completed within 60 h, while BDT requires 8-9 days. Unlike BDT, LSRM allowed one to measure the graded changes in the metabolism and the growth rate of Mycobacterium tuberculosis in response to various concentrations of the drug. It permits the measurement of the relative prolongation of the replication time by the drug or the test compound. With LSRM it was possible to detect the phase of growth during which the test compound shows or begins its antituberculous activity. It improves our understanding of the antituberculous activity of the test compound and hence is more advantageous. It is rapid, reliable, quantitative and more sensitive than BDT. LSRM is thus suitable for the evaluation of new drugs.

Antitubercular Agents↗