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Chlorotriethylphosphine gold (SK & F 36914) administered orally to rabbits produced aurosomes in the synovial membrane. These aurosomes were similar to aurosomes produced by parenteral or intra-articular injections of soluble gold salts such as sodium aurothiomalate and aurothioglucose. This study shows, (1) that an orally administered gold compound is capable of producing gold deposits in the synovial membrane, and (2) that such compounds may have a future in the treatment of rheumatoid arthritis. more...

Intra-articularly administered sodium aurothiomalate (Myochrysine) produced aurosomes containing characteristic electron dense contents (indicating the presence of gold), in the chondrocytes of rabbit articular cartilage. At first the aurosomes were bounded by a membrane but later the electron dense contents were seen lying free in the cytoplasmic matrix. Such deposits were detectable up to 14 months after injection of Myochrysine but none were found at later time intervals (18 months and 2 years). There was a reduction in the population of superficial chondrocytes (Zone I) while those in deeper zones (Zones II and III) showed an increased content of intracytoplasmic filaments. It is thought that these are regressive or degenerative changes produced by gold. more...

Haematomas were produced in rabbits by subcutaneous injection of autologous blood. Clotting and marked lysis of erythrocytes was noted in these haematomas, but there was no evidence of fragmentation of erythrocytes prior to or after ingestion by macrophages as has been reported in other sites such as the peritoneal cavity and the joint cavity. The phagocytosis of intact erythrocytes, lysed erythrocytes and haemoglobin led to the formation of three main types of lysosomal bodies; (1) myelinosomes containing whorled osmiophilic membranes, (2) siderosomes containing haemosiderin, and (3) myelinosiderosomes containing a mixture of osmiophilic membranes and haemosiderin. more...

Core defects produced in the medial femoral condyle of the rabbit were studied by scanning electron microscopy and light microscopy over a period of 2 years. In some cases the defect was filled by hyaline articular cartilage with a fairly smooth surface, but in others the tissue was markedly fibrillated and resembled fibrous tissue and fibrocartilage. Appearances suggesting disintegration of the newly formed cartilage were seen in some cases. It would appear that a continuation of this process can lead to the exposure of subchondral bone. In one instance no repair tissue or new cartilage could be identified but the surrounding old cartilage had formed a shelf over the defect. The cartilage surrounding the defect was either normal or showed superficial fibrillation, and/or flow formation, and/or fissures. more...

Electron probe x-ray analysis of siderosomes produced in the rabbit synovial membrane by repeated injections of autologous blood revealed two kinds of siderosomes; (1) those containing a small amount of phosphorus and, (2) those in which no phosphorus was detectable. On the basis of these findings and past studies it is concluded that haemosiderin is an inorganic compound of iron, probably a hydrated ferric oxide and that a variable amount of organic material (proteins, lipids, phospholipids, etc.,) probably occurs in company with the haemosiderin in the siderosome, but these variable components which decrease in amount with the passage of time cannot be considered as an integral part of haemosiderin. more...

Intra-articular injection of sodium aurothiomalate (Myochrysine) into rabbit knee joints produced lysomes (aurosomes) of a characteristic morphology in synovial intimal cells and subsynovial macrophages. Such lysosomes are distinct and different from other lysosomes and those seen after injection of sodium thiomalate. A study of the morphological events that occur after injection of gold salt shows that at first the aurosome contains electrondense granules but later membranous formations (myelinoid membranes) presenting as rod-like and curled structures develop. With electron probe x-ray analysis, gold, phosphorus, and traces of calcium were detected in the aurosome. more...

Full thickness defects (core defects) violating subchondral bone were created in the weight-bearing area of articular cartilage lining the rabbit medial femoral condyle. The repair reaction that follows has two components: (1) a sliding and flowing of cartilage over the edge of the defect and (2) a filling of the defect by repair tissue arising from the marrow spaces. Past studies have paid little or no attention to cartilage flow but this first scanning electron microscopic study of deep defects shows that it is an important phenomenon which materially affects the changes that occur and also the outcome of such injuries. Briefly, we have found that in most cases the cartilage flows downwards into the core defect. The repair tissue then grows along and over the "toed-in" catilage. In other cases the flowing cartilage rides over the repair tissue from the marrow spaces and as a result of load bearing and joint movement, becomes frayed and drawn out into long ribbons and rope-like structures. more...

Parenteral administration of bismuth subnitrate produced intranuclear inclusions in the rabbit kidney tubules. In glutaraldehyde fixed material these inclusions had a homogeneous appearance but in osmicated material some of these inclusions showed a granular and fibrillar substructure. In relatively thick unstained sections prepared from unosmicated tissues, it was found that the inclusions were electron-dense, but they vanished from view when the electron beam was focussed on them. This phenomenon is thought to be due to the presence of bismuth, which is a mental with a high electrical resistance and low thermal conductivity. With the aid of electron-probe analysis the presence of bismuth was demonstrated in these inclusions and it seems possible that sulphur may be present here. more...