Biomedical subjects
Publications and source records attributed to F Laurent.
This report describes a 34-year-old woman with an anomalous origin of the left coronary artery from the pulmonary artery. The angiographic pattern was clearly demonstrated by magnetic resonance imaging (MRI) performed before surgery. This case suggests that MRI could play an important role in the pre-operative assessment of coronary anomalies.
Relationships between intestinal OM and N disappearance from bags and rumen incubation time (Rt) were studied in goats fed straw, urea- or ethylenediamine-treated straw (Ed). Intestinal OM disappearance seemed to vary inversely to Rt. Rt was without any significant influence on intestinal N disappearance from urea and Ed straw.
Ultrastructurally and immunocytochemically identified A, B and D cells are highly concentrated in the splenic bulb of the duck pancreas. Ultrastructural features of normal A, B and D cells are similar in the duck and in other species so far studied. However, normal D cells present a striking characteristic, i.e. apical accumulation of dense bodies, which seem to derive from multivesicular bodies and are probably involved in a catabolic regulatory process. Subtotal pancreatectomy in the duck, leaving the splenic bulb and inducing transient diabetes, produces strong secretory stimulation of A and B cells, as indicated by the development of the rough endoplasmic reticulum and the Golgi apparatus and transient degranulation, more marked in B cells. Numerous B cells with degenerative aspects, observed after 12 days, seem to be exhausted following prolonged hyperstimulation: this could explain why diabetes reappears in some cases. In contrast, in D cells, functional inhibition after surgery is suggested by a dramatic increase in the number and size of the dense bodies, associated with a marked decrease in secretory vesicle storage. The morphological data correlate well with the previously reported evolution of plasma and pancreatic hormone concentration after surgery, and suggest that the normal inhibitory control of glucagon and insulin secretion by the local release of somatostatin might be reduced or suppressed during transient diabetes in subtotally depancreatized ducks.
Metastases are the most frequent malignant tumors of the kidney, but these lesions are of late onset in neoplastic disease. The 19 cases reported here were all investigated with various imaging techniques (CT 12 cases, ultrasonography 12 cases, urography 8 cases, angiography 2 cases, MRI 1 case). The most common primary malignancies were lung cancer, melanoma and cancer of the contralateral kidney. In this series, 8 of the lesions were solitary, and 9 were unilateral. Tumor vascularity was evaluated in 15 cases: 14 of these lesions were hypovascular. The differential diagnosis includes small cysts, lymphoma, bilateral renal cancer, multiple small abscesses and multiple small infarcts.
The authors report the contribution and the limits of CT and MRI in the thoracic and extrathoracic staging of bronchogenic carcinoma. From data of a personal study and of the literature, findings and performances of CT and MRI are reported and compared for the evaluation of mediastinal and parietal extension and in the detection of nodes and metastases. Their respective places and indications are underlined.
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The decline of 3 plasma pancreatic hormones, glucagon (G), insulin (I) and somatostatin (S) was studied in fasting ducks after total pancreatectomy. The results show that the decrease of plasma glucose is highly correlated with the disappearance of G, while no important variation of the G/I ratio occurs during the period of observations (80 minutes) the animal being kept fasted. No participation of pancreatic S in glucose metabolism could be detected, the origin of peripheral S in the fasting state seeming due to the intestine for about 50%.
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A case of hepatocarcinoma on cirrhosis with portal hypertension is described. The anatomy of splenorenal anastomoses and their ultrasound and CT scan imaging characteristics are reviewed, and the interest of differential diagnosis from adrenal masses emphasized. Its importance is enhanced by the fact that the portal hypertension may be unrecognized as in the present case. Diagnostic effectiveness of ultrasound and CT scan imaging is discussed.
The lesser omentum is a peritoneal partition that can be divided into two portions: superior or gastrohepatic ligament and inferior or duodenohepatic ligament, although differentiation is sometimes difficult. Ultrasound and CT scan imaging allowed perfect definition of vascular and glandular elements contained in the omentum, and normal morphology is described. Masses developing between the two leaves of which it is constituted usually project in front of adjacent vascular structures and/or prolonged into the liver hilum, and a fatty layer separates them from large prevertebral vessels. These different guidelines allow them to be distinguished from retroperitoneal celiomesenteric adenopathies. These expansive processes are almost always of glandular origin secondary to primary digestive, retroperitoneal, pelvic and even bronchial tumors. In contrast, primary tumors are rare in this region.
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A case of stress fracture of the femoral shaft is reported. The part of CT scan imaging is emphasized in the diagnosis and follow-up of this rare location.
During the 1973-1983 period considerable changes have taken place in the techniques and indications of coronary bypass. In a homogeneous series of 3095 patients operated upon by the same group, changes in techniques have been: the introduction in routine coronary bypass of the membrane oxygenator which provides optimal biological conditions and the prolonged circulatory assistance so necessary to high risk patients, and the application to coronary bypass of microsurgical techniques enabling surgeons to perform multiple anastomoses on small vessels easily and safely. Changes in indications have been characterized by a progressive decrease in operations on patients with one-vessel lesions and normal left ventricular function to the benefit of those with multiple-vessel lesions and altered left ventricular function. As a result, the complete revascularization rate and the number of anastomoses have increased continuously. These two categories of changes have not modified the overall in-patient mortality rate, but there has been a significant increase in peri-operative necrosis.
For more than 10 years homologous bone stored at -20 degrees C has been used to fill large bone cavities after cystectomy. This article outlines the principles of collecting, storing, and preserving the homograft, presents special aspects of the surgical technique, and reports long-term results.
Glucagon, somatostatin and insulin secretions were evaluated in a new type of perfusion preparation: the naturally A and D cell rich splenic bulb of duck pancreas. Stable basal levels were observed with 11 mM glucose, corresponding to normoglycaemia, and all secretions were stimulated by 1 mM 3-isobutyl-1-methyl-xanthine and by 10 mM arginine, demonstrating the technique's validity. In the absence of aminoacids in the perfusion medium, A cell blindness to glucose was corrected by physiological levels of insulin (2 ng/ml); insulinodependency of A cells, and unresponsiveness of D cells to glucose, probably not ruled by insulin, were observed. However, in the presence of aminoacids, glucagon was inhibited and somatostatin secretion stimulated by glucose (33 mM), independently of insulin (2 ng/ml). Aminoacids greatly influenced pancreatic hormone release.
The authors propose a simplified technique for the resection of dystrophic aneurysms of the ascending aorta with aortic regurgitation. The technique is based on a special method of shaping the Dacron tube, so that the proximal line of suture extends to the bottom of the sinuses of Valsalva, in front of and behind the coronary ostia. The results in 27 operated patients are reported. The global hospital mortality was nil. Seventy four per cent of patients had no complications at all 22 per cent had minor and rapidly regressive complications. The long-term results were assessed in 20 patients. There were no secondary deaths or reoperations. Angiographic and/or echocardiographic control performed in 12 cases showed no valvular dysfunction or recurrence of the aneurysmal process. The advantages of this technique are its simplicity, its good short and long-term results and the possibility of using a bioprosthesis for aortic valve replacement.
Fifty of 75 serum samples collected in the West Nile district of Uganda between August 1972 and July 1973 contained antibodies reactive with human T-cell leukemia (lymphotropic) virus type 3 (HTLV-III; mean titer, 601), while 12 of 75 samples were positive in a similar test for HTLV type 1 (HTLV-1) antibodies (mean titer, 236). The samples were screened by enzyme-linked immunosorbent assay and positive results were confirmed by a newly developed unlabeled antibody-peroxidase procedure with enhanced sensitivity for detection of antibody binding to immunoblots of HTLV-III antigen, demonstrating antibodies to proteins with molecular weights of 24,000, 41,000, and 76,000 in nearly all positive samples. Analysis of titration data indicated enhanced titers of antibody against HTLV-III and HTLV-I when coinfection occurred. The high prevalence and relatively low titers [compared to serum from patients with acquired immune deficiency syndrome (AIDS)] of antibodies recognizing HTLV-III proteins in sera from this population at a time that may predate or coincide with the appearance or spread of the AIDS agent (HTLV-III) suggest that the virus detected may have been a predecessor of HTLV-III or is HTLV-III itself but existing in a population acclimated to its presence. It further suggests an African origin of HTLV-III.
The transient diabetes, observed in ducks after subtotal pancreatectomy, induces hyperglycaemia and hyperamino-acidaemia. Threonine and alanine are quantitatively the most important amino acids in both normal and diabetic animals, suggesting a particular role of threonine in amino acid metabolic pathways in the duck. The hyperaminogenic role of the decreased insulin levels, and the neoglucogenic effect of a low, but not negligible, glucagon secretion, during diabetes, are discussed.