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Biomedical subjects

J G Barbin

Publications and source records attributed to J G Barbin.

9 recordsLinked to original sources
PubMed1988

Biomechanics of the calvarium.

The authors question whether strengthening beams and spans for the calvarium really exist and, if so, what are their exact anatomic counterparts and their exact function in the resistance of the calvarium. They opine that this function is of secondary importance except for the frontal and internal occipital pillars. The resistance of the calvarium must rather be attributed to its sandwich structure, with local bracing where the constraints are too severe. While they believe in the existence of such braces as the occipital pillars between the calvarium and the endochondral skull base, they prefer the concept of the mastoid pillars. The mastoid process is a structure with a thin shell and alveolar content, which has the advantage of giving the sternocleidomastoid and digastric muscles a bigger area of attachment to a light structure.

Biomechanical Phenomena↗
PubMed1987

A physico-mathematical model for the human femur, with and without a prosthesis, under the static constraints of one-legged stance.

The authors present a physico-mathematical model of a human femur, under "monopodal" static constraints, using the finite elements method. Three examples are considered: a normal femur, a femur implanted with a short-stem prosthesis without cement, and a femur implanted with a long-stem prosthesis without cement. The lines of isoconstraints were compared in the three examples, as well as the main constraints (direction and intensity). From the results, the authors suggest that a prosthesis made of titanium is currently best even though its YOUNG's modulus differs from that of the bone. A prosthesis of composite material is possible in the future. While the intensity of the constraints is nearly the same at the level of the epiphysis for the short-stem and long-stem prosthesis it seems that the short-stem prosthesis fitted accurately without cement is the best solution. The introduction of a hip prosthesis modifies the normal curve of the loaded femur by changing the center of this curve.

Biomechanical Phenomena↗
PubMed1987

[Immunohistochemical study of 4 cases of mucoid and argyrophilic carcinoma of the breast].

Three to 5% of breast carcinomas are argyrophilic, including some which are mucinous and thus "composite", whereas there are no argyrophilic cells in normal breast nor in benign breast pathology. This raises the problem of the origin and type of these argyrophilic cells. We carried out a histologic and immunohistochemical study in 4 such cases of mucoid tumors containing at least 50% argyrophilic cells. Two of these tumors presenting node involvement were also studied immunohistochemically. The histologic study showed colloid and intragalactophoric proliferation areas in cell cases and some endocrine areas in 2 out of 4 cases. Argyrophilic cells were present in all of these areas. True mucoargyrophilic amphicrine cells were found primarily in colloid areas. None of these tumors were argentaffin. Immunohistochemical study was performed by the PAP method using antibody directed against VIP, ACTH, PP, somatostatin, bombesin, calcitonin, gastrin, prolactin and GH. Three out of four tumors were positive with VIP. Moreover one of them contained ACTH cells and a metastasis of this tumor contained bombesin cells. No tumor was positive with the other anti-sera tested. This study is related to the rare series in the literature which report secretion of ACTH, catecholamins, bombesin, gastrin, VIP, PP, somatostatin, prolactin, etc. The number of cases reported to date remains too low to show a significant prognostic difference between amphicrine tumors and other mammary carcinomas.

Adenocarcinoma, Mucinous↗
PubMed1984

[Anesthesia protocol in the swine. Effects of bleeding on circulation and acid-base equilibrium].

Haemodynamic parameters and their variations after the loss of 250 and 500 ml of blood under anaesthesia were studied in nine, 11 to 12 week-old, domestic swine weighing 37.4 +/- 2.6 kg. Premedication consisted of 2 ml azaperone i.m. Anaesthesia was induced with thiopentone, followed by suxamethonium to allow the easy placement of a cuffed endotracheal tube. Anaesthesia was maintained with phenoperidine and pancuronium. The animals were mechanically ventilated with a 50/50 nitrous oxide-oxygen mixture. A catheter was inserted in each of the femoral artery, upper hepatic vein, vena cava and portal vein. Right atrial, pulmonary and wedge pressures were measured; stroke volume, systemic and pulmonary resistances were calculated (fC 90 c X min-1, Pa 82 mmHg, Pra 4.7 mmHg, Ppa 24 mmHg, Ppw 11.6 mmHg, Q 4.45 l X min-1 and Rsa 1460 dyn X s X cm-5). The swine were then bled. After a bleed of 250 ml (t1), the haemodynamic parameters were significantly modified. After another bleed of 250 ml (t2), the heart rate only was significantly higher than at t1; but the blood transfusing could not re-establish a normal haemodynamic state. Blood samples were obtained to measure pH and total CO2 in a systemic artery, and the upper hepatic veins, vena cava and portal vein: the results suggested that the liver took part in the removal of acid metabolites.

Acid-Base Equilibrium↗