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Biomedical subjects

A Vachon

Publications and source records attributed to A Vachon.

At least 19 recordsLinked to original sources

Neochondrogenesis in free intra-articular, periosteal, and perichondrial autografts in horses.

Periosteal autografts were obtained from the medial aspect of the proximal portion of the tibia, and perichondrial autografts were obtained from the sternum. Using arthroscopic visualization, each autograft was placed as a loose body into 1 tarsocrural joint in 6 young horses (2 to 4 years old). Horses were hand-walked daily, starting the day after surgery, for a total of 6 h/wk for 8 weeks. Eight weeks after autograft implantation, radiographs were taken of each tarsocrural joint and were interpreted with regard to mineralization in the transplanted autografts. Autografts were then surgically removed, and examined macroscopically and microscopically for viability, size, and production of chondroid tissue. All autografts appeared viable and most had evidence of growth. Longest-by-shortest axis value, cross-sectional area, and perimeter were greater in perichondrial autografts than in their periosteal counterparts in 3 horses, but the difference was not significant. Neochondrogenesis was observed in 5 of 6 periosteal grafts and in 1 of 6 perichondrial grafts. Furthermore, the amount of chondroid tissue produced in periosteal autografts was significantly (P less than 0.05) greater than that produced in the 1 perichondrial graft. The chondroid tissue produced by periosteal autografts had morphologic and matrical staining properties similar to those of hyaline cartilage.

Animals

Internal fixation of a proximal metatarsal fracture in a calf.

An open proximal metatarsal fracture was identified in a 9-month-old calf. Open reduction, internal fixation, and external coaptation were used to repair the fracture. The calf recovered without complications and was reported to be sound 6 months after surgery.

Animals

A radioprotector: cysteamine, inhibits oxygen transport in lipidic membranes.

Spin labeling techniques make possible the observation of oxygen diffusion or concentrations in phospholipid membranes. In such a system, cysteamine, depending upon the molecular cysteamine/DPPC ratio and the pH conditions, inhibits oxygen transport, and this result provides an original explanation for cellular hypoxia after cysteamine administration.

Biological Transport

Evaluation of the repair process of cartilage defects of the equine third carpal bone with and without subchondral bone perforation.

To determine the effect of subchondral bone drilling (forage) on the cartilage repair process after injury has occurred, a cartilage defect (1 cm in diameter) was created on the radial facet of the proximal surface of each third carpal bone in 6 adult horses. In one of the third carpal bones (right or left thoracic limb) of each horse, a 1-cm cartilage defect was created, and 5 holes (1 mm in diameter and 10 mm deep) were drilled through the subchondral bone into the cancellous bone. In the other thoracic limb, an identical defect was created, but not drilled. Analyses of cell numbers and types in the synovia and the mucin precipitate quality were done before, at 1 week after, and 3 weeks after surgical manipulation was done and showed no significant difference between the joint environment of drilled carpi and those of nondrilled carpi. At 21 weeks after surgical manipulation was done, each joint was examined radiographically, macroscopically, and microscopically to compare the condition of the joints and the state of repair of the cartilage in each defect. The amount of surface of the defect covered by the dense fibrous and fibrocartilagenous repair tissue and the thickness of the repair tissue were significantly greater (P less than 0.05 and P less than 0.01, respectively) in the drilled carpal bones. In addition, the attachment of the repair tissue to underlying chondro-osseous tissue was better in the drilled carpal bones. Fibrocartilage was resurfacing the drilled defects, whereas only fibrous tissue was present in the nondrilled defects.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals

Erythrocyte volume distribution analysis and hematologic changes in two horses with immune-mediated hemolytic anemia.

Immune-mediated hemolytic anemia was diagnosed in two horses on the basis of regenerative anemia, increased erythrocyte fragility in hypotonic saline, autoagglutination, and a positive direct antiglobulin (Coomb's) test. During steroid therapy partial resolution of the anemia was indicated by rising packed cell volume, macrocytosis, and bone marrow erythroid hyperplasia. Using erythrocyte volume distribution histograms (erythrograms), the regenerative response was characterized by analysis of macrocytic and normocytic erythrocyte subpopulations. In both horses, a gradual net increase of about 2 X 10(6) macrocytes/microliter occurred over a four- to five-week period. Over the same interval there was a gradual decrease in the number of normocytes. We suggest that the macrocytes remained large through this period rather than contributing to normocyte population growth. Erythrograms may provide an additional means of evaluating erythrocyte regeneration in horses.

Anemia, Hemolytic, Autoimmune

[Alpha heavy chain disease].

Alpha chain disease is a fairly rare disease (less than 80 cases have been diagnosed to date) the diagnosis of which should be considered as a routine in France when a young arab or oriental jew presents with digestive symptoms such as chronic diarrhoea, abdominal pain of abdominal tumour. The diagnosis of the disease requires two examinations 1) serum immunoelectrophoresis with monospecific anti-IgA antiserum, which alone isolates in 100% of cases the paraprotein. 2) Exploratory laparatomy seems advisable in all cases, for it alone permits multiple lymph node and intestinal biopsies whict are necessary to determine the stage of the disease, the prognosis and treatment. 3) Generally speaking, heavy chain disease seems to represent like Burkitt's lymphoma, a model for experimental carcinoma.

Adolescent

[Detection and determination of alpha-feto-protein in human serum. Use in hepato-gastroenterology].

The presence of alpha-foeto-protein (A.F.P.) was sought in the serum of 520 patients, suffering from various digestive disorders, using two methods: double immuno-diffusion and counter immuno-electrophoresis on cellogel--a more sensitive technique. A.F.P. was detected on 90 of the 520 patients. A.F.P. was measured by radial immunodiffusion or by electro-immunodiffusion on cellogel. Study of the values obtained in various kinds of hepatic disorders indicates that high levels (more than 10 mg/1) are seen almost solely in association with primary carcinoma of the liver, whilst lower levels (less than 10 mg/1) are found in the majority of hepatic disorders, without having any precise significance. The interest of the clinician should therefore be directed not towards the presence or absence of A.F.P. but to its level, which alone is significant.

Adenoma, Bile Duct