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Biomedical subjects

D F McDonald

Publications and source records attributed to D F McDonald.

At least 19 recordsLinked to original sources

A new monoclonal anti-A antibody BIRMA-1. A potent culture supernatant which agglutinates Ax cells, but does not give undesirable reactions with B cells.

A monoclonal anti-A antibody, BIRMA-1, has been evaluated and found to be eminently suitable as a blood-grouping reagent. The culture supernatant is potent, avid and specific as demonstrated by its reactivity with a large sample of donor bloods tested manually and on the Olympus PK 7100 automated blood grouping machine. Over 100 cord blood samples were tested manually, and all were correctly grouped using this antibody. No false-positive reactions were obtained with papainized group B cells. Reagent prepared from BIRMA-1 detected most examples of Ax and all other A subgroups and A variants tested. Negative reactions with B(A) cells indicate that it is possible to have an antibody capable of detecting Ax which will not react with B cells from individuals with high levels of galactosyltransferase.

ABO Blood-Group System

A histologic comparison of aseptic loosening of cemented, press-fit, and biologic ingrowth prostheses.

The histology of interface membranes from aseptic loosened prostheses of various types including cemented, press-fit, and biologic ingrowth varieties was compared. Pseudosynovial implant-facing surfaces were present in specimens from all types. The remaining portions of these membranes showed distinct characteristics as well. Cemented implant membranes contained many macrophages and giant cells and evidenced frequent granuloma formation. Press-fit membranes consisted of poorly vascularized, dense fibrous tissue within the loosened press-fit membrane. Macrophages and giant cells were rare, except in one specimen containing ceramic debris particles. Biologic ingrowth membranes were the most vascular and contained loosely organized connective tissue and islands of woven bone. Macrophages were common. One out of six specimens from patients with rheumatoid arthritis contained massive numbers of lymphocytes and plasma cells but not mast cells. The greatest numbers of mast cells were present in membranes from patients with osteoarthritis and in all cases were associated with the presence of stainless steel and/or chrome cobalt particles.

Arthritis, Rheumatoid

Establishment of a large collection of extracted teeth for research.

A collection of over 14,000 teeth extracted at the Prince Philip Dental Hospital since 1982 has been organized and catalogued on a computerized database management system. The computer catalogue provides, for each tooth in the collection, information on the age and sex of the patient, and the date of extraction and condition of the tooth. The catalogue can be searched according to any combination of the descriptive variables in the database record. Researchers, including visiting scientists, can borrow teeth from the central "tooth library" on a temporary or permanent basis. Further information on particular teeth (e.g. patient's medical and dental histories, dental radiographs) can be obtained from patients' charts. Establishment of this collection has greatly facilitated the work of researchers in clinical dentistry, dental anatomy, and dental anthropology.

Humans

Histochemical localization of cathepsin B, dipeptidyl peptidase I, and dipeptidyl peptidase II in rat bone.

The histochemical distribution of the thiol proteases cathepsin B and dipeptidyl peptidase I and the serine protease dipeptidyl peptidase II was examined in rat bone and joint using amino acid derivatives of 4-methoxy-2-naphthylamine (MNA). The liberated MNA was then visualized by simultaneous coupling with fast blue B. Cathepsin B was examined with CBZ-Arg-Arg-MNA, dipeptidyl peptidase I (DPP I) with Gly-Arg- or Pro-Arg-MNA, and dipeptidyl peptidase II (DPP II) with Lys-ALA- or Lys-Pro-MNA. Bright red reaction product indicative of proteolytic activity was observed in most cell types associated with bone and its surrounding connective tissues, including osteocytes, osteoblasts, chondrocytes, chondroblasts, fibroblasts, and macrophages. Surprisingly, protease activity in osteoclasts could not be established with certainty, and it was concluded that these enzymes are either absent, present in very low amounts, or secreted as soon as they are synthesized rather than stored within the cell. The cells of the resting zone of the growth plate were intensely reactive for DPP II but were only moderately reactive for cathepsin B and DPP I. The reverse was true of the proliferating and hypertrophic layers. The protease activity observed in bone, cartilage, tendon, ligament, and synovium would be expected to contribute significantly to normal protein metabolism as well as to pathological destruction in these tissues.

Animals

A comparative study of new substrates for the histochemical demonstration of acid phosphomonoesterase activity in tissues which secrete acid phosphatase.

The histochemical demonstration of acid phosphatase activities against phosphoethanolamine (PEA), phosphorylcholine (PC), and D-ephedrine phosphate (DEP) are reported for a variety of rat tissues and are compared to acid beta-glycerophosphatase (beta GPase) activity. Intense acid beta GPase activity was demonstrated in all tissues examined. However, liver, kidney, intestine, spleen and bone marrow cells failed to exhibit any enzyme activity against PEA, PC, or DEP. In addition, significant differences in the hydrolysis of these substrates were noted among the tissues that did demonstrate activity (bone, tooth, oral mucosa, sebaceous gland, and prostate gland). These observations suggest that PEA, PC, and DEP are more specific substrates for acid phosphatase than beta GP and permit the differential localization of several distinct acid phosphatase isoenzymes.

Acid Phosphatase

Acid D-ephedrine-O-phosphatase activity in rate ventral prostate lysosomes.

Hydrolysis of D-ephedrine-O-phosphate (DEP) by rat ventral prostrate was investigated by electron microscopic hystochemistry. In contrast to previous reports that DEP is exclusitely hydrolyzed by a secreted nonlysosomal acid phosphatase, enzyme reaction product was present in supranuclear and basal lysosomes.

Acid Phosphatase

Talc granuloma presenting as a testicular mass.

A case of a benign talc granuloma in a 3-year-old boy is reported. Surgical wound contamination with various lubricant dusts from surgeons' gloves and resultant granuloma formation is a well known phenomenon. However, there are few reported cases of peritesticular masses owing to talc granulomas.

Child, Preschool