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Biomedical subjects

A Prat

Publications and source records attributed to A Prat.

At least 127 records · Page 7Linked to original sources
PubMed1989

[Acute traumatic rupture of the thoracic aorta. Role of delayed surgical treatment].

Acute traumatic rupture of the thoracic aorta (ATRTA) is considered to be an emergency which requires immediate surgery. However surgical mortality is high with an average of 20% in the literature. Twenty-seven patients were observed from 1973 to 1986. Three patients were not operated on (Group I). Twenty patients had immediate surgery (group II) with 60% deaths, 4 patients underwent delayed surgery (Group III) with 25% deaths. Analysis of causes of deaths shows that mortality is mainly due to the severity of associated lesions. Associated lesions were present in 72% of patients who did not survive and in only 37% of the survivors. Associated lesions may be lethal initially (E.G. Brain trauma) or they may be aggravated by the thoracic procedure. Complications from associated lesions may also compromise the outcome of the thoracic procedure. It is well known that the majority of deaths from ATRTA are observed within 24 hours. Immediate repair of the aortic lesion should remain the rule when aortic rupture is isolated or associated with moderate injuries. However, in some cases with severe and multiple associated lesions who survive the initial aortic injury, delayed repair of ATRTA could be considered.

Acute Disease↗
PubMed1988

Cyclophosphamide modulates arachidonic acid metabolism by peritoneal macrophages.

The treatment of mice with a single dose of cyclophosphamide (Cy) (200 mg/kg) enhanced the chemiluminescence (CL) response of peritoneal macrophages (PM) triggered with opsonized zymosan (OpZ). The enhanced CL response could not be attributed to the stimulation of the cyanide-insensitive respiratory burst, since neither superoxide anion release nor immune complex-triggered cytotoxicity, an oxygen-dependent lytic mechanism, were increased in Cy-PM. Then, products of the oxidative metabolism of arachidonic acid were measured. It was found that Cy-PM exhibited increased release of prostaglandin E2 and leukotriene C4 in response to OpZ when compared with resident PM. In contrast, similar levels of thromboxane B2 production were observed in both populations. The activation of macrophage arachidonic acid metabolism reported here may contribute to the immunomodulating action of Cy.

Animals↗
PubMed1988

[A new method of laser angioplasty by contact sapphire: preliminary results. Apropos of 20 cases].

We report our first 20 cases of peripheral laser angioplasty using an optic fibre with contact sapphire tip. The equipment included a teflon catheter on which was screwed a round sapphire 2.2 mm in diameter. A 600 microns optic fibre connected to a Nd-Yag laser instrument was introduced into the catheter and placed in contact with the sapphire. Twenty patients underwent recanalization of femoral or popliteal arteries occluded on a length of 5 to 45 cm. The sapphire-tipped catheter was introduced by the Seldinger technique up to the site of occlusion. The 15 watt laser emission was set at intervals of one second. Sixteen out of the 20 occluded arteries were recanalized. Among the 4 failures, 3 were due to perforation and 1 to intraparietal progression. Angioplasty was performed with laser alone in 3 cases and with laser completed by balloon catheter in 13 cases. The minimum diameter of the laser-induced channel was 2 mm and was significantly increased (3.8 mm) by complementary balloon dilatation. In the 3 patients who underwent laser angioplasty alone, no noticeable improvement in distal blood flow was demonstrated by doppler velocimetry, and reocclusion occurred either soon afterwards (n = 2) or later (n = 1). Midterm results were much better in patients who had had additional balloon dilatation: early (3rd day) or late (2 months) reocclusion took place in only 3 patients. In the remaining 10 patients, followed up for periods of 1 week to 18 months (mean: 6 months), clinical improvement and recanalization were maintained.

Angioplasty, Balloon↗
PubMed1987

Telomeric site position heterogeneity in macronuclear DNA of Paramecium primaurelia.

In Paramecium primaurelia, the macronuclear gene encoding the G surface protein is located near a telomere. In this study, multiple copies of this telomere have been isolated and the subtelomeric and telomeric regions of some of them have been sequenced. The telomeric sequences consist of tandem repeats of the hexanucleotides C4A2 or C3A3. We show that the location where these repeats are added, which we call the telomeric site, is variable within a 0.6-0.8-kb region. These results are discussed in relation with the formation of macronuclear DNA.

Animals↗
PubMed1987

Neutrophil-mediated cytotoxicity triggered by immune complexes: the role of reactive oxygen metabolites.

Normal human neutrophils triggered by precipitating immune complexes (IC), soluble IC (sIC) or heat-aggregated IgG (HAIgG) displayed low levels of cytotoxicity towards nonsensitized target cells. Catalase, but not heated catalase, completely impaired this nonspecific cytotoxicity (NSC), suggesting a key role for hydrogen peroxide (H2O2) in the lysis of target cells. Superoxide dismutase (SOD) and certain HO. and 1O2 scavengers were unable to exert significant effects. Three haem-enzyme inhibitors, sodium azide, sodium cyanide and 3-amino-1,2,4-triazole did not decrease neutrophil NSC, but markedly enhanced it. This data suggest that the mechanism involved was not dependent upon myeloperoxidase (MPO). The analysis of neutrophil-mediated ADCC indicates that oxygen-dependent but MPO-independent mechanisms appeared to be operative in this system. It was also found that the microfilament disrupting agents, cytochalasin B (CB) and dihydrocytochalasin B (dhCB), as well as the chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (FMLP), significantly enhanced NSC. In contrast, these compounds partially inhibited ADCC. This cytotoxic system provides a suitable model to study events that may occur during the course of immune complex diseases and also permits the evaluation of alternative lytic mechanisms triggered through neutrophil Fc gamma receptors.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1987

[Popliteal venous aneurysm. Apropos of 3 cases].

The popliteal venous aneurysm is a rare cause of recurrent phlebitis and pulmonary embolus. In reference to 3 personal cases, their etiology, their role in the occurrence of phlebitis, the place of phlebography and vascular sonotomography respectively, are discussed. The treatment is essentially surgical.

Adult↗
PubMed1986

Nucleotide sequence of the Paramecium primaurelia G surface protein. A huge protein with a highly periodic structure.

The complete DNA sequence of the G surface protein of Paramecium primaurelia has been determined. It contains an open reading frame of 8145 nucleotides devoid of introns and coding for a protein of 329,000 Mr. Analysis of the deduced amino acid sequence reveals remarkable features such as important internal homologies and a periodic structure, which could be dictated in part by the rigid scaffolding of cysteine residues. The predicted secondary structure shows a quasi absence of alpha-helix and an abundance of beta-pleated sheets and random coils. The monotony of the amino acid sequence is in favour of a structural role for the protein. Interestingly, homologies with other proteins are limited to surface antigens of trypanosomes. Finally, our data are consistent with a genetic code for paramecium which differs from the "universal" code by the assignment of TAA and TAG codons to glutamine.

Amino Acid Sequence↗
PubMed1985

The efficacy of diflunisal in osteoarthritis of the knee. A Canadian Multicenter Study.

Diflunisal, a long acting antiinflammatory analgesic was compared in high (1000 mg daily) and low (750 mg daily) doses with placebo in a randomized, double blind study of 6 weeks' duration in patients with osteoarthritis of the knee. Two hundred twenty-seven patients from 47 centers completed the study--high dose 69, low dose 88 and placebo 70. Pain relief was significantly greater with both doses of diflunisal than with placebo. Both patient and investigator global opinions reflected significantly greater efficacy with diflunisal. Although there was a trend in favour of the higher dose, no statistically significant differences in efficacy were found between the 2 doses of diflunisal studied. Overall adverse reactions with diflunisal were no more frequent than with placebo, but gastrointestinal side effects were significantly greater with the higher dose.

Adult↗
PubMed1984

Experience with 813 aortic or mitral valve replacements with the Carpentier-Edwards bioprosthesis: Five year results.

813 patients underwent aortic (AVR) or mitral valve replacement using the Carpentier-Edwards bioprosthesis from 1976 to 1983. Operative mortality was 5.49% for AVR and 4.59% for MVR. Late mortality and complications were classified using criteria described by the Stanford Group. Actuarial survival at 5 years was 87.9% +/- 2.7% for AVR and 91.1% +/- 1.4% in MVR. Thromboembolism occurred at low rates of 0.48% pt yr for AVR and 0.90% pt yr for MVR. 98.2% +/- 0.90% of AVR and 96.9% +/- 1.3% of MVR pts were free from thromboembolism at 5 years. The low incidence of thromboembolism during the early postoperative period played a role in the low rates observed in the complete study. There was no valve thrombosis. Anticoagulation with warfarin was used in 35% AVR and 75% MVR with rates of bleeding complications of 1.20% pt yr and 1.10% pt yr. Overall valve failure rate was 2.04% pt yr at 5 years for AVR and 1.55% pt yr for MVR. Rates of reoperation for tissue failure remained low (0.24% pt yr for AVR and 0.32% pt yr for MVR). The advantage of a low rate of thromboembolism was not outweighed by the specific problems of bioprosthesis at 5 years.

Actuarial Analysis↗
PubMed1984

[Diastolic restriction caused by an encysted hemopericardium a year after coronary bypass].

The case of a 54 year old patient presenting with congestive cardiac failure one year after single aorto-coronary bypass surgery is reported. Paraclinical investigations showed a pericardial effusion compressing the inferior wall of the heart. Echocardiography was essential for diagnosis. This localised compression was responsible for the haemodynamic changes of adiastole. Pericardial drainage confirmed the diagnosis of an encysted hemopericardium containing about 300 ccs of liquid. Right and left cardiac catheter studies before and after surgery, and 8 months postoperatively, showed progressive normalisation of the intracardiac pressures. A volume expansion stress test excluded possible associated pericardial constriction. Therefore, the finding of diastolic restriction with a residual effusion after cardiac surgery should orientate management towards pericardial drainage before considering pericardectomy.

Coronary Artery Bypass↗
PubMed1984

[Posttraumatic infarction with a surgically treated floating thrombus of the left ventricle. Apropos of a case].

Forty-two days after severe thoracic trauma which had led to thrombosis of the left renal artery and to nephrectomy, a 22 year old patient developed anterior wall infarction. Echocardiography and coronary and left ventricular angiography showed distal occlusion of the left anterior descending artery and the presence of a large, mobile thrombus at the left ventricular apex. The thrombus was removed surgically without any complications but a small thrombus adherent to the ventricular scar was observed postoperatively. After a discussion on the different possible physiopathological mechanisms, the authors conclude that the patient probably suffered primary myocardial contusion which led to secondary occlusion of the LAD artery, late myocardial infarction and extension of the initial intraventricular thrombus. This case illustrates the value of two-dimensional echocardiography in the detection and follow-up of ventricular thrombosis.

Adult↗
PubMed1982

[The long term results of reparative surgery for aorto-iliac stenosis and chronic obstruction. 563 cases followed up for 2 to 13 years (author's transl)].

The results of surgery for aorto-iliac obliterative arterial disease deteriorate progressively over 10 years to leave only 44% good results, 39% deaths, 3% poor results and 14% amputations. Nevertheless, the quality of the surviving patients is satisfactory with 72% good functional results at 10 years and a permeability rate of 76% of reparative procedures at the same period. It is certain that current improvements having resulted in a decrease in early mortality will affect the long-term results in view of the tendency to horizontalisation of graphs beyond the first six months.

Aged↗