Biomedical subjects
Publications and source records attributed to D Chappard.
Polyester fibers are not dissolved by either glycol methacrylate or methyl methacrylate. Commercial polyester wadding is consequently an advantageous material to use in getting precise orientation of tissue specimens during embedding in methacrylates.
A one-step clearing and embedding procedure for alizarin red S stained skeletons is described. Embryos are fixed in formalin, skinned and eviscerated. After staining in a 10 mg/liter solution of alizarin red S in 5% aqueous KOH, specimens are dehydrated in a graded series of acetone-polyester monomer solutions. Finally, the specimens are embedded at room temperature in the polyester resin. A special reusable metallic mold is described for embedment of large fetuses. Specimens previously cleared in glycerol can be processed with this method.
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Paget's disease is a human bone dysplasia with a probable viral origin. SEM studies on anorganic and acid etched biopsies confirm the osteocondensation and the structural and textural abnormalities (presence of woven bone). Corrosion casts revealed a complex scaffolding structure of vascular channels. On resting fronts, the domains are small and irregular and surfaces are different from human fetal woven bone. Mineralizing fronts extend largely on bone surfaces and present evidence of abnormal thickness. Resorption surfaces extend irregularly in multiple directions and are often found unusually deep. Irregularity of osteoclastic lacunae was also evidenced. This SEM study suggests that an osteoblastic qualitative dysfunction could be associated with the osteoclastic changes.
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Necropsy of a 20 weeks born fetus. Horse shoe kidney. Atresia of the urethra at of the vagina.
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We present plans for an original holder for long-edged glass knives (Ralph knives). Knives are prepared by hand-breaking of commercial window glass (3 mm thick), for cutting large blocks of tissue embedded in a water-miscible plastic resin, glycol methacrylate.
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A mixture of pure and anhydrous glycol methacrylate and methyl methacrylate is used as an embedding medium for iliac bone biopsies. Infiltration is carried out at -20 C with the embedding medium and a cold inactivated catalyst-initiator system. Raising the temperature to 4 C initiates polymerization and limits the peak temperature of polymerization to 25 C. In this way, such thermolabile enzymes as osteoclastic acid phosphatase are preserved. After staining, sections are dehydrated in polyethylene glycol 400 30% in 2-propanol. This gives flat sections and improves staining properties.
Osteoclasts are known to have a high acid phosphatase content. We have adapted the simple simultaneous mono-coupling azo-dye method of Grogg and Pearse to undecalcified bone sections. A cold embedding in a mixture of glycol and methyl methacrylate was shown to well preserve the enzyme activity. Sodium alpha-naphtyl phosphate (1 mg/ml) and fast violet B (2 mg/ml) are used in 0.1 M acetate buffer, pH 5.0. The addition of 1 mM L(+) sodium tartrate selectively inhibits the acid phosphoprotein phosphatase ("osteoblastic acid phosphatase") but not osteoclastic lysosomal acid phosphatase. Counterstaining with phosphomolybdic aniline blue WS leads to well contrasted sections, providing accurate measurements of osteoclast number.
We present a fetus with an umbilico-cephalic adherence, probably secondary to an early amnion rupture. The fetal ectoderm and the collagenous layers of the chorion can attach as large amounts of fibronectin are present in the amniotic fluid. Until now, no case of this particular type of "amnion rupture sequence" syndrome has been reported.
Two cases of sirenomelia with multicystic renal dysplasia (Potter's type II A) are reported. One case was discovered on fetal ultrasonography. Multicystic renal dysplasia in sirenomelia is an additional plea for a primitive mesoblastic defect in the caudal regression syndrome.
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Pure glycol methacrylate (GMA) is an excellent embedding medium which allows High Performance Optical Microscopic studies. However presence of methacrylic acid (MA) small amounts (usually 1 to 3%) leads to intense background staining of the section. A simple and reliable chemical purification procedure is exposed which leads to an extra-pure GMA free of MA and hydroquinone.
We report the anatomic and histological study of a fetus that had multiple developmental abnormalities which were secondary to a premature rupture of the amniotic sac followed by adhesion of the fetus to the placental chorion. There have been many case histories of this syndrome reported recently throughout the world. This is the first recent case reported in France.