Search PubMed⌕ Search

Biomedical subjects

J Willemot

Publications and source records attributed to J Willemot.

At least 19 recordsLinked to original sources
PubMed1991

[Palatine amygdalectomy through the ages].

This paper describes the development of the techniques of amygdalectomy through the ages. It would appear that Susruta de Bénares performed such an operation as early as the first century, but I personally have no documents on him. On the other hand, the operation is described in scrupulous detail by Celse, at the same period, and was not greatly different from our current dissection. The Judeo-Arab world was familiar with amygdalectomy from the very beginning, and the techniques of Abulcassis, Avicenne and Haly Abbas used dissection, pulling-out and cauterization as early as the 10th century. Guillemeau, a student of Paré, was the first to propose a ligature. In the 18th century, Benjamin Bell remained faithful to the ligature technique, and devised on uvulotome, which gave Physick the idea of an amygdalotome, from which derived the instrument of Sluder-Ballenger, incorrectly called the guillotine, given that its principle was based on pulling-out rather than cutting. Nevertheless, dissection remains today the technique most widely employed.

Amygdala↗
PubMed1990

History of rhinology: functional surgery of the nose in France at the turn of the century.

The first reference to an attempt at functional surgery of the nose which we have discovered in France concerns Blandin (Paris 1798-1849) who "corrected" septal deviations with a punch; one arm is introduced into each nostril. Heylen performed a submucous resection in 1847, Chassaignac in 1851 and Demarquay in 1859 through the external median columellar route. In 1876 Richet carried out a resection of the deviated septum after having elevated the whole cartilaginous pyramid, achieved by a horizontal incision of the base of the columella. Paul Berger recommended, in 1883, a subperichondrial chisel resection of the salient part of the septum. In 1888, Miot approached septal thickening with galvano-caustic chemicals using metal plates or through a method called galvano-puncture. In 1892 Escat resected the cartilaginous arch and its corresponding mucosa after having separated the contralateral mucosa with injected water. In 1903, Caboche referred to both operations used at that time to correct cartilaginous septal deviations, e.g. Petersen's operations (submucous resection) and Asch's operation (fracture with repositioning). In 1905, Blanc distinguished between three types of operations: 1. Procedures based upon the fracturing the septum or its straightening and its maintenance with a splint. 2. Procedures designed in order to overcome the elasticity of the cartilage by making incisions followed by its retention in place. 3. Submucous resection of the cartilage based upon the principle that the septum is too big for its surroundings. In 1917, Dangouloff and Woyatchek developed a septoplasty technique, many modern operations being only pale copies of theirs. It consisted of four possibilities: mobilization, straightening, circular resection and partial resection.

France↗
PubMed1983

Effect of purine nucleoside phosphorylase substrates on the mitogen-induced stimulation of murine T and B spleen cells.

The effect of culture with exogenous purine nucleoside phosphorylase substrates (especially deoxyguanosine) on the proliferation of mitogen-stimulated murine spleen cells was investigated. Con A-stimulated 3H-thymidine incorporation in unpurified and purified T cells was appreciably inhibited by culture in the presence of 100 microM deoxyguanosine. LPS-stimulated incorporation in unpurified and purified B cells was affected in a similar manner. Culture with guanosine inhibited incorporation in both mitogen-stimulated T and B cells to almost the same extent as deoxyguanosine. Inhibition of 3H-thymidine incorporation in T cells by deoxyguanosine was not modified by concomitant inclusion of deoxycytidine in the culture medium. In addition, deoxyguanosine had effects on T cell proliferative responses during the early phases of stimulation and even prior to stimulation with the mitogen. These results contrast with those reported for human lymphoid cells, where deoxyguanosine was much more potent that guanosine, and where only T cells were affected. They suggest that mechanisms other than the one involving inhibition of ribonucleotide reductase may also be important in the effects of deoxyguanosine on certain lymphoid cells.

Animals↗
PubMed1982

Effects of glycerol and fructose on purine synthesis de novo and on PP-ribose-P availability in rat liver cells.

Incubation of freshly isolated rat liver cells with glycerol resulted in an initial decrease, followed by an increase in purine synthesis de novo and in PP-ribose-P availability. The magnitude of these effects was dependent on the concentration of glycerol; as it increased, the initial period of latency or inhibition was prolonged, and the extent of the subsequent stimulation was greater. The intracellular Pi concentration and the [14C]ATP/[14C]ADP ratio were also initially decreased in these cells, and they too returned subsequently to normal values. All these changes were similar to those induced by fructose under the same conditions. The increase in PP-ribose-P availability always preceded that in purine synthesis de novo, indicating that, under most circumstances, PP-ribose-P availability is limiting for purine synthesis de novo. Finally, PP-ribose-P synthesis in these cells varied in parallel with the intracellular Pi concentration and with the ATP/ADP and ATP/AMP ratios.

Adenine↗
PubMed1982

[Factors altering purine metabolism in liver cells].

This paper reviews results of a study of various factors altering 5-phosphoribosyl-1-pyrophosphate (PRPP) availability in freshly isolated rat liver cells. Total PRPP availability is not changed in the presence of allopurinol but in the competition for available PRPP is increased. Changes of PRPP availability due to phosphate, electron acceptors, or glycerol are usually accompanied by similar changes in the rate of purines synthesis de novo.

Allopurinol↗
PubMed1981

Protein synthesis, amino acid uptake, and pools during isoproterenol-induced hypertrophy of the rat heart and tibialis muscle.

Chronic administration of isoproterenol (ISO) produces hypertrophy of the rat heart and tibialis muscle. With doses of 0.1, 0.3, and 0.6 mg/kg, hypertrophy of the heart is significantly by the 3rd day of treatment. Maximum cardiac enlargement attained with doses of 0.3 and 0.6 mg/kg occurs after 21 days and averages 40% above control values. ISO increases tibialis muscle weight by 15%. Incorporation of 14C-labeled amino acids into total heart and tibialis muscle protein is stimulated by ISO. Maximum stimulation occurs 2-3 h after the fifth daily injection of ISO. The stimulation of incorporation is greater during the first few days of treatment and decreases gradually thereafter. A single injection of ISO decreases the total amino acid concentration of the serum, heart and tibialis muscle whereas the rate of amino acid uptake by the heart and tibialis muscle is increased by ISO. The production of hypertrophy of the heart and tibialis muscle in diabetic or castrated animals by ISO suggests that insulin and testosterone are not essential in the mechanism of ISO-induced hypertrophy.

Amino Acids↗
PubMed1980

Purine synthesis de novo and its regulation in rat hepatocytes.

Purine synthesis de novo and its regulation were studied in freshly isolated hepatocytes from fed adult male rats. The cells incorporated [14C]formate mainly into purine ribonucleotides. The immediate effect of increasing the concentration of inorganic phosphate in the incubation medium was an increase in 5-phosphoribosyl 1-pyrophosphate (PP-ribose-P) availability and a stimulation of purine synthesis de novo. However, prolonged incubation of cells in 25 mM phosphate resulted in a decreased PP-ribose-P availability and purine synthesis de novo. Methylene blue and phenazine methosulfate decreased PP-ribose-P availability and purine synthesis de novo although they stimulated considerably the pentose phosphate pathway. In contrast, epinephrine and glucagon increased significantly PP-ribose-P availability and purine synthesis de novo, but they did not change the activity of the pentose phosphate pathway. These results show a relationship between PP-ribose-P availability and purine synthesis de novo in rat hepatocytes. They emphasize the complexity of the regulation of PP-ribose-P availability.

Animals↗
PubMed1978

Actin- and myosin-like filaments in rat brain pericytes.

Heavy meromyosin (HMM) labeling was used to identify the nature of the filaments which form bundles in the cytoplasm of the pericytes in brain tissue. Rat brain tissue pieces were incubated in glycerol solutions at 4 degrees and then transferred into buffer (pH 7.0), (1) without HMM, (2) with HMM, (3) with HMM + 5 mM ATP, and (4) with HMM + 2.5 mM Na+ pyrophosphate. In pericytes from untreated tissue, smooth-surfaced microfilaments, averaging 6 nm in diameter, appear to branch and anastomose and to anchor on the plasma membrane. After exposure to HMM, the number and the density of the microfilaments are strikingly increased. These tightly-packed microfilaments are now heavily coated with exogeneous HMM thus increasing in width to 18-20 mm. They intertwine in closely-woven networks. After incubation in HMM solutions containing ATP or Na+ phosphate, they are no longer coated with thick sidearms. It can thus be concluded that these microfilaments are of actin-like nature. In addition, after incubation in ATP, they are intermingled with, and converge onto the surfaces of, thick, tapered filaments, which we have tentatively identified as of myosin-like nature. Thus, it appears that certain of the major elements necessary for contraction are present in brain pericytes.

Actins↗