Relationship between meniscal degeneration and element contents.

The purpose of this study is to investigate the relationship between meniscal degeneration and element contents. The contents of elements (calcium, phosphorus, sulfur, and magnesium) in the menisci from 17 patients with osteoarthritis (OA) of the knee, 6 with rheumatoid arthritis (RA), and 2 who underwent the surgical operation for malignant tumors (control) were analyzed by inductively coupled plasma-atomic emission spectrometry, and the menisci were divided into four stages (Stage 0-3) of histological degeneration. The calcium contents of the menisci were 0.26 +/- 0.16 in Stage 0, 0.50 +/- 0.37 in Stage 1, and 0.69 +/- 0.66 in Stage 2, respectively (the values represent mg elements/g dry tissue). They increased with the progression of the stage. This tendency was found in the menisci with OA, but was not clear in those with RA. The calcium content in the control group was 0.17 +/- 0.09 mg/g. There was no significant relationship between the stage of degeneration and the contents of phosphorus, sulfur, or magnesium. The calcium content of the meniscus might indicate the degree of meniscal degeneration.

Accumulation of calcium and phosphorus in the mitral valve in comparison with the abdominal aorta and the scaphoid bone.

To clarify why calcification of the mitral valve occurred, the authors chose the abdominal aorta and the scaphoid bone among many arteries and bones, and they studied both relationships in element contents between the mitral valve and the abdominal aorta and between the mitral valve and the scaphoid bone. The subjects consisted of 11 men and 8 women, ranging in age from 52 to 96 yr. The accumulation of calcium and phosphorus occurred progressively with aging in the mitral valve, whereas it became the highest in the sixties in the abdominal aorta and did not increase thereafter. The accumulation of calcium and phosphorus occurred in the abdominal aorta earlier than the thoracic aorta, in which it became remarkable in the seventies. It should be noted that in regard to the accumulation of calcium and phosphorus, no significant correlations were found between the mitral valve and the abdominal aorta. It is suggested that calcification of the abdominal aorta is not essentially accompanied by calcification of the mitral valve. The scaphoid bone was chosen among many bones consisting mainly of spongy bone and the relationship was examined between the calcium content in the mitral valve and the bone mineral density of the scaphoid bone. It was found that there was a low relationship between them. Therefore, it is suggested that a part of the surplus calcium released from bones is deposited in the mitral valve.

Age-dependent decreases of phosphorus and magnesium in human Achilles' tendons.

To elucidate changes of human tendons with aging, the authors studied age-related changes of elements in human Achilles' tendons by inductively coupled plasma-atomic emission spectrometry. The subjects consisted of seven men and seven women, ranging in age from 61 to 97 yr. It was found that the content of calcium increased progressively with aging in the Achilles' tendons, whereas the contents of phosphorus and magnesium decreased gradually with aging. The previous investigations demonstrated that the content of calcium and phosphorus increased progressively with aging in most, but not all, human tissues, except for the bones. In ligaments, such as the anterior cruciate ligament and the ligament of the head of the femur, which are histologically similar to the Achilles' tendon, it was previously found that both the contents of calcium and phosphorus increased with aging in the ligaments. It should be noted that the content of phosphorus in the Achilles' tendons decreased during the aging process. In addition, it was found that there was a very high direct correlation between phosphorus and magnesium contents in the tendons, but not between calcium and phosphorus contents.

Age-related changes of element contents in the human meniscus.

The relative contents (RCs) of elements in the human menisci from 23 subjects in the age range between 65 and 93 yr were analyzed by inductively coupled plasma atomic emission spectrometry. The RCs of sulfur, calcium, and phosphorus in menisci increased progressively until the 80s, being the highest in the 80s, and thereafter decreased. The RCs of magnesium in menisci increased progressively until the 90s. Regarding the medial and lateral menisci, higher RCs of magnesium and iron, and a lower RC of phosphorus were found in lateral menisci in comparison with those in medial menisci. There were sexual differences in the RCs of calcium and phosphorus of medial and lateral menisci. The RCs of calcium and phosphorus were about 50% higher in women's menisci than in men's. Histological examinations showed that structureless mucoid masses were observed in the menisci, with very high RCs of calcium and phosphorus being detected.

Histological and biochemical evaluation of osteogenic response in porous hydroxyapatite coated alumina ceramics.

We compared the osteogenic response in porous alumni (Al) and hydroxyapatite coated porous alumni ceramic (HA/Al) by grafting rat bone marrow cells with these implants subcutaneously in the back of syngeneic rats. The ceramics did not show any bone formation without marrow, but did when combined with marrow cells. The osteogenesis in HA/Al began directly on the ceramic surface, but in Al began away from the ceramic surface, and fibrous tissue interposition was seen between the de novo bone and its surface. Alkaline phosphatase activity and bone specific bone gla protein content in HA/Al with marrow were both about three times higher than in Al with marrow. These results indicate that HA/Al has excellent osteoconductive properties and that a composite of marrow and HA/Al is clinically applicable osteogenic biomaterial.

Long circulating emulsion carrier systems for highly lipophilic drugs.

With the aim of developing of emulsion carrier systems for lipophilic drugs with the potential for prolonged circulation in the blood or hepatic targeting, the in vivo disposition of four model compounds, i.e., [3H]prostaglandin E1, [3H]retinoic acid, [14C]cholesterol, and [14C]cholesteryl oleate with calculated log PC(oct) values of 2.15, 6.61, 9.46, and 18.3, respectively, injected with various emulsion formulations, were studied in mice. Small sized emulsions of about 100 nm in diameters, with compositions of egg phosphatidylcholine (PC): soybean oil = 1:1 (small PC emulsion) and PC: egg sphingomyelin (SM): soybean oil = 0.7:0.3:1 (small SM emulsion), and a conventional emulsion with a diameter of about 250 nm and a composition of PC: soybean oil = 1:1 (large PC emulsion) were compared. Highly lipophilic [14C]cholesteryl oleate, a marker of emulsion particles, indicated diverse in vivo behaviors; i.e., the small SM emulsion produced prolonged circulation in the blood, and the small PC emulsion followed this, while the large PC emulsion was rapidly uptake by the liver. Thus, a reduction in size and coating with SM on the surface of oil droplets resulted in avoidance of the reticuloendothelial system (RES). Disposition profiles of other test compounds differed, depending on their lipophilicities: [14C]cholesterol showed disposition patterns in all formulations similar to those of [14C]cholesteryl oleate, but moderately lipophilic [3H]prostaglandin E1 and [3H]retinoic acid showed common disposition profiles, regardless of emulsion types, suggesting their rapid release from the emulsion carriers. These results suggest that small SM emulsion and large PC emulsion can act respectively as long circulating and liver targeting carriers for highly lipophilic drugs with log PC(oct) larger than 9.

Analysis of primary bone formation in porous alumina: a fluorescence and scanning electron microscopic study of marrow cell induced osteogenesis.

Porous alumina ceramics alone and combined with rat marrow cells were implanted subcutaneously in the back of syngeneic Fischer rats. Fluorochrome-labeling was performed post operatively and the ceramics were harvested 6 and 8 weeks after implantation. Undecalcified sections of the implants were observed under fluorescence microscopy and the de novo bone-ceramic interfacial areas were analyzed by a scanning electron microscope equipped with an electron probe microanalyzer. Alumina ceramics alone did not show any bone formation, while all marrow cell loaded ceramics showed new bone formation 6 and 8 weeks after implantation. Bone formation was first observed in the center of the pores and proceeded in a centrifugal direction, leading to contact with the ceramic. These results suggest that bone marrow cells have inherent osteogenic capacity and in the pore region of alumina ceramics progression of the osteogenesis causes the dissipation of intervening fibrous tissue between the de novo bone and alumina ceramic surface.