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Biomedical subjects

F Fernandez

Publications and source records attributed to F Fernandez.

At least 127 records · Page 7Linked to original sources
PubMed1987

[Porcine valvular bioprosthesis. Results 6 years later].

Between January, 1977 and December, 1980, 128 porcine bioprostheses were implanted in 109 European patients hospitalized at the Boucicaut hospital, Paris: 47 were aortic valve replacements (AVR), 43 mitral valve replacements (MVR) and 19 dual valve replacements (DVR). The operative mortality rate was 11% (12 patients): MVR 21%, AVR 6.4%, DVR 0%. 3 patients were lost sight of. The mean follow-up period was 59.3 months (3-96 months). The overall survival rate at 6 years, including early deaths, was 74.4 +/- 8%: MVR 66.1 +/- 15%, AVR 84.9 +/- 10%, DVR 68.6 +/- 20%. Eighteen late deaths were reported (3.7% patient-years [PY]), 3 of which were due to the valve (0.6% PY). The probability at 6 years of escaping death due to the valve was 96.3 +/- 4%: MVR 96.9 +/- 4%, AVR 100%, DVR 87 +/- 17%. Complications associated with the valve were observed in 17 patients (3.5% PY); they were: degeneration in 2 (0.8% PY), thromboembolic accident in 2 (0.4% PY), haemorrhagic accident in 4 (0.8% PY), endocarditis in 5 (1% PY) and simple disinsertion in 2 (0.4% PY). The probability at 6 years of escaping a complication due to the valve was 80.7 +/- 10%: MVR 90.4 +/- 13%, AVR 81.8 +/- 13%, DVR 55.3 +/- 35%. The probability at 6 years of escaping death and re-operation due to the valve was 88.5 +/- 8%: MVR 96.0 +/- 6%, AVR 87.9 +/- 11%, DVR 60.2 +/- 37%. This study and those already published show that compared with mechanical prostheses, bioprostheses clearly reduce the incidence of thromboembolic and haemorrhagic accidents.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1987

[Dilated cardiomyopathy: electrocardiographic forms].

The shape of the QRS complex was analyzed in 90 cases of dilated cardiomyopathy and was divided into 6 electrocardiographic types which may be interpreted as follows: A predominant S wave in V2, V3 and V4 leads, surrounded by a reduced QRS voltage in the other leads was the most frequent characteristic pattern, being found in 31 cases (34.4%). This pattern coexisted with a lack of R wave progression from V1 to V4, with primary disorders of ST-T and with alterations in P wave. The deep S wave is probably due to a growth of vectors in the base of the left ventricle and in the septum in response to lesions in the rest of the myocardium. Second in frequency (22.2%) came left bundle branch block, with 20 cases. If to these are added the 19 cases of left anterior half-block observed, dilated cardiomyopathy appears as the major cause of the cardiac pathology that partially or completely interrupts the left branch. These cases also show that the lesions predominate in the left ventricle. The 14 cases (15.5%) of QS with elevated and convex ST-T betray extensive areas of fibrosis or necrosis. This pattern is characteristically located at the apex of the heart and associated with ventricular tachycardia. In 11 cases (12.2%) the QRS complex was normal in shape but associated with depressed ST-T and atrial disorders. This shows that the ventricular myocardium which produces QRS is neither badly damaged nor hypertrophic, but that repolarization is highly sensitive to the constant alterations of the subendocardial layers observed in dilated cardiomyopathy. Left ventricular hypertrophy was seen in 9 cases (10%).(ABSTRACT TRUNCATED AT 250 WORDS)

Arrhythmias, Cardiac↗
PubMed1987

Analgesic effect of alprazolam in patients with chronic, organic pain of malignant origin.

Effective analgesia is a crucial factor in promoting quality of life for cancer patients. While undergoing treatment with the minor tranquilizer alprazolam for a coincidental psychiatric disturbance, 39 patients with malignancies and an associated causalgic pain syndrome had a marked analgesic response. Diagnostic and treatment guidelines for organic pain syndromes are reviewed, as are indications for the use of anticonvulsants and benzodiazepines as analgesic adjuvants. The results of this study suggest that the use of benzodiazepines for patients with this refractory pain syndrome should be evaluated further.

Adjustment Disorders↗
PubMed1987

Respiratory dyskinesia due to antiemetic therapy in a cancer patient.

Cancer patients commonly receive neuroleptics as antiemetics to relieve nausea and vomiting induced by chemotherapeutic agents. Respiratory dyskinesia, an infrequent, acute, neuroleptic-induced, dystonic reaction, is a potentially life-threatening entity that responds promptly to anticholinergic medication.

Adult↗
PubMed1986

A low molecular weight heparin alters the fetal coagulation system in the pregnant sheep.

Standard heparin and a LMWH, CY222 do not cross the placenta nor alter fetal coagulation when injected into the pregnant ewe. We found that another LMWH, Pharmuka-10169 (PK-10169) alters fetal coagulation without crossing the placenta in the pregnant sheep. To characterize this anticoagulant we measured the in vitro and in vivo effects of 125I-PK-10169 in maternal and fetal plasmas following administration of PK-10169 to the mother or fetus. The fetal anticoagulant activity was not neutralizable by protamine sulphate and was attributable to the inhibition of thrombin but not factor Xa. In vitro, the fetal anticoagulant activity had properties similar to dermatan sulphate; both catalyzed the inhibition of thrombin but not factor Xa by sheep plasma; and neither was neutralizable by protamine sulphate. These effects were due to the enhanced neutralization of thrombin by heparin cofactor II. We conclude that PK-10169 does not cross the placenta, but does induce the release of an endogenous dermatan sulphate-like substance which alters fetal coagulation.

Animals↗
PubMed1986

[Prolonged bleeding time in severe anemia].

The frequency and importance of prolonged bleeding time were studied in patients affected by a severe anemia (haemoglobin less than 8 g/dl). A Simplate bleeding time test was performed in 25 patients suffering from various haematological disorders, with a platelet count greater than 100,000/cu mm and a normal or increased factor VIII complex. Patients with acute leukaemia, myeloproliferative disorders or chronic renal impairment were excluded from the study. Bleeding time was prolonged in 12 patients; their mean haematocrit was not different from that of the 13 other patients whose bleeding time was in the normal range. Bleeding time was less prolonged than in patients with chronic renal insufficiency in spite of a lower mean haematocrit (previous study). Fifteen patients were investigated a second time after partial or full correction of the haematocrit; in all but one, the bleeding time was reduced and/or normalized. This study suggests that severe anaemia may be an additional hemorrhagic risk factor in patients with another cause of bleeding.

Anemia↗
PubMed1986

Cigarette smoking during coronary angiography: diffuse or focal narrowing (spasm) of the coronary arteries in 13 patients with angina at rest and normal coronary angiograms.

To evaluate the acute effects of cigarette smoking on coronary arteries (CA), repeated coronary angiograms were performed in 13 patients with angina at rest and with normal coronary angiograms at basal state, during smoking, and then after methylergometrine (MEM) and after intracoronary nitroglycerin. Smoking induced anginal pain in three patients, triggered spasm (focal narrowing) in six, and/or an abnormal segmental diffuse narrowing (greater than 30%) in eight. The narrowing of the left CA was on average -21 +/- 13% (P less than 0.001), with more important narrowing of the mid-left anterior descending (-29 +/- 19%, P less than 0.001). The mean of the maximal segmental narrowing by patient was -34 +/- 13% (P less than 0.001). MEM produced similar effects and induced focal CA spasms in nearly the same patients at the same sites. Cigarette smoking may induce vasoconstrictive effects on CA in patients with rest angina and normal coronary angiograms. This action is not dose-dependent and may be initiated by less than one cigarette. These observations offer a new perspective for the understanding of the role of smoking in the precipitation of coronary events.

Adult↗
PubMed1986

Respective role of antithrombin III and heparin cofactor II in the in vitro anticoagulant effect of heparin and of various sulphated polysaccharides.

The in vitro anticoagulant effects of standard heparin (SH) and of seven other sulphated polysaccharides (SPS) were investigated by measuring activated partial thromboplastin time (APTT) prolongation of normal plasma and of plasmas selectively depleted of antithrombin III (AT III), of heparin cofactor II (HC II) and of both heparin cofactors. This allowed the determination of the relative contribution of each of the two heparin cofactors to the SPS anticoagulant effect. The SPS varied in their relative activities as catalysts of thrombin inhibition by purified AT III or HC II. The anticoagulant activities of heparin and dermatan sulphate were primarily attributable to their ability to enhance thrombin inhibition by AT III and HC II respectively. Heparin had an additional minor anticoagulant activity which was independent of both AT III and HC II. Pentosan polysulphate, high molecular weight dextran sulphate, heparin with low affinity for AT III and a sulphated heparin derivative had weaker anticoagulant activities in normal plasma than standard heparin. The anticoagulant activities of these last four SPS in plasma depleted of both AT III and HC II were similar to their respective activities in normal plasma. This suggests that these SPS act by directly preventing thrombin generation rather than by enhancing thrombin inhibition.

Antithrombin III↗
PubMed1986

The haemorrhagic and antithrombotic effects of dermatan sulphate.

Heparin and dermatan sulphate are effective antithrombotic agents but the clinical use of heparin is complicated by haemorrhage. The haemorrhagic effect of dermatan sulphate is unknown. In this study we compared the antithrombotic, haemorrhagic and anticoagulant effects of heparin and dermatan sulphate in rabbits. The antithrombotic effect was measured as prevention of venous thrombus formation. The haemorrhagic effect was measured as 51Cr-blood loss from standardized cuts in rabbit ears. The anticoagulant effect was measured as changes in the APTT, TCT and circulating anti-factor Xa level, and the formation of 125I-thrombin/inhibitor complexes ex vivo. The effect of heparin and dermatan sulphate on collagen-induced platelet aggregation was measured ex vivo. Maximal antithrombotic effects of heparin and dermatan sulphate were achieved with 70 and 500 micrograms/kg respectively. A 20-fold increase in heparin dose caused an 8-fold increase in blood loss and higher doses (40- and 80-fold increases) caused further dose-related increases in blood loss (13- and 35-fold increases respectively). In contrast, a 20- to 40-fold increase in the antithrombotic dose of dermatan sulphate did not increase blood loss and an 80-fold dose increase caused only a 7-fold increase in blood loss. There was no relationship between the antithrombotic and haemorrhagic effects of either heparin or dermatan sulphate and their anticoagulant activities. In contrast, there was a relationship between the dose-related enhancement of blood loss by these glycosaminoglycans and the inhibition of collagen-induced platelet aggregation ex vivo. These results suggest that dermatan sulphate is less haemorrhagic than heparin at equivalent antithrombotic doses, and that the haemorrhagic effect is associated with a glycosaminoglycan-induced platelet defect.

Animals↗
PubMed1986

Comparative capacity of orally administered amoxicillin and parenterally administered penicillin-streptomycin to protect rabbits against experimentally induced streptococcal endocarditis.

A single-intramuscular-dose immunization regimen with a penicillin G-streptomycin combination was compared with three oral-dose amoxicillin regimens for the capacity to prevent Streptococcus sanguis infections of experimentally induced valvular heart lesions in rabbits. Challenge doses of 10(4), 10(6), and 10(8) CFU of a strain of S. sanguis equally susceptible to penicillin and amoxicillin were used in this study. Measured by recovery of test organisms from endocardial lesions, the lowest concentration of these inocula was infective for 60% of the recipients; the two higher-concentration inocula were infective for all recipients. The penicillin G-streptomycin combination provided complete protection against infection with inocula of all sizes. A single-oral-dose amoxicillin regimen (50 mg/kg of body weight) prevented endocarditis when rabbits were challenged with 10(4) CFU, but protection diminished with increasing inoculum concentrations. Similar results were achieved when five oral doses of amoxicillin (8.5 mg/kg of body weight) added at 8-h intervals were included in the single-oral-dose regimen. In contrast, when rabbits received two oral doses of amoxicillin (50 mg/kg of body weight) with a 10-h interval between doses, prophylaxis was fully effective with even the highest inoculum concentration.

Amoxicillin↗
PubMed1986

[Hemodynamic evaluation of the Carpentier-Edwards porcine bioprosthesis and the Hancock pericardial bioprosthesis in aortic position].

Forty-four asymptomatic patients were catheterised at Boucicaut Hospital 9.5 months after aortic valve replacement to assess the haemodynamic performances of 21 Hancock pericardial (HP) and 23 porcine Carpentier-Edwards (CE) (standard model) bioprostheses, implanted in the aortic position. Left heart catheterisation was performed from a femoral approach; the simultaneous gradient was measured by planimetry and the functional valve surface area calculated at rest and after exercise. The resting calculated surface area of the HP was greater than that of the CE bioprostheses (equation: see text). The transvalvular pressure gradient was lower in the HP than in the CE group (7.8 +/- 4 vs 15.3 cf243 6 mmHg; p less than 0.005). After exercise (15 patients) the calculated surface area increased with the increased transvalvular blood flow in both groups but at each flow rate the calculated valve surface area was greater in the HP group. The haemodynamic performance of the CE bioprosthesis is inferior to that of the HP bioprosthesis, especially in the smaller models. However, the CE bioprosthesis would seem to be mechanically more reliable in the long term than the HP bioprosthesis has since been withdrawn from the market.

Adult↗
PubMed1986

[Phono-mechanographic evaluation of aortic stenoses. Contribution of the B1-maximum murmur/B1-B2 index].

The diagnostic value of phonomechanography in valvular aortic stenosis was reassessed with a rarely used index, the ratio S1-maximum intensity of the systolic murmur/S1-S2, or Thiron's index, the author of which only studied the correlations with the aortic transvalvular pressure gradient. The results obtained by the author being considered inconclusive, we decided to examine its correlations with aortic valve surface area calculated with the Gorlin's formula. The study was carried out in 38 patients with pure aortic stenosis, in whom 4 phonomechanographic parameters, the corrected left ventricular ejection time (Meiners), the carotid pulse half peak time, the S1-maximum intensity of the murmur interval and Thiron's index, were compared with the transvalvular pressure gradient and the aortic valve surface area at catheterisation. The first two parameters mentioned above were of limited value (correlations with aortic valve surface area r = 0.315, p less than 0.05 and r = 0.477, p less than 0.01 respectively). On the other hand, a good correlation was obtained with Thiron's index (r = 0.624, p less than 0.001) which was better than that found with the interval between S1 and maximum intensity of the systolic murmur (r = 0.483, p less than 0.001) in a population not excluding subjects with cardiac failure. These results indicate that: when Thiron's index less than or equal to 0.45, the aortic stenosis is probably mild (aortic surface area greater than 0.8 cm2), when Thiron's index is 0.46 greater than 0.56, the aortic stenosis is likely to be moderately severe (aortic surface area 0.8 less than 0.5 cm2), when Thiron's index is greater than 0.57, the aortic stenosis is probably severe (aortic surface area less than 0.5 cm2). In our series, Thiron's index was the best phonomechanographic parameter for the assessment of pure aortic stenosis. It could not be calculated in 10 out of 48 patients; this drawback was not encountered with the corrected left ventricular ejection time or the carotid pulse half peak time.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗