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Biomedical subjects

D Mitrovic

Publications and source records attributed to D Mitrovic.

At least 37 records · Page 2Linked to original sources
PubMed1983

Cell density of adult human femoral condylar articular cartilage. Joints with normal and fibrillated surfaces.

Cell and clonal density, lacunar and clonal diameters, and mean number of cells per single clone were studied in human femoral condylar cartilage of normal and osteoarthrotic joints. The values were related to the age of the subjects, the sampling site within the joints, and the depth from the articular surface. Cell density in every zone of both normal and diseased tissue decreased with increasing distance from the surface and increasing age. Cell density was significantly lower in age-matched osteoarthritic articular cartilage with an intact surface than in that of normal joints. The age-related decrease in the cell density accompanied an increase in the density of empty lacunae. The density of Alcian blue-stained cells, which actively synthesize proteoglycans as demonstrated by histoautoradiography, diminished with advancing age in all zones of articular cartilage. The percentage of these cells consistently decreased in the superficial and increased in the deep layers of the tissue in both normal and osteoarthritic joints. The clonal density was higher in the nonweight-bearing than in weight-bearing areas, and it increased with age, whereas the mean clone diameter and clonal cell number decreased.

Adult↗
PubMed1983

[Anti-collagen antibodies. Their detection in rheumatoid polyarthritis, chronic atrophic polychondritis and various chronic inflammatory rheumatism].

The authors administered by passive haemagglutination, natural or denatured type I and II anticollagen antibodies in the serum of 83 rheumatoid polyarthritis, 20 ankylosing spondylarthritis, 30 relapsing polychondritis, 13 diffuse sclerodermics, 12 Gougerot-Sjögren syndrome patients. Type II natural anti-collagen antibodies are common in relapsing polychondritis (37 percent). They are rarer in rheumatoid polyarthritis (15 percent) and the frequency is identical to that found in patients suffering from gonarthrosis and coxarthrosis. Natural type II anti-collagen antibodies may be occur in etiopathogenesis of relapsing polychondritis. Denatured II ant-collagen antibodies are common during ankylosing spondylarthritis (35 percent) and diffuse sclerodermia, and are found in rheumatoid polyarthritis (23 percent) and in Gougerot Sjögren syndrome (25 percent). They possibly play a pathological role in these diseases although this has not been proved. They are detected almost as often in the synovial fluid of inflammatory rheumatisms (53 percent) and in gonarthrosis (41 percent).

Adult↗
PubMed1982

[Response of the joint tissues to the presence of a foreign body implanted into the rabbit knee. A new model of experimental arthrosis].

The joint tissues (synovium, articular cartilage and bone), respond rapidly and consistently to the presence of a piece of polypropylene surgically implanted into the Rabbit knee joint. In the contact of a foreign body, a synovium proliferates in an attempt to isolate and exclude the intruder from the joint cavity. The articular cartilage degenerates at the sites of maximal pressure. Its superficial layer undergoes cell necrosis and fibrillation and is progressively destroyed in the process of mechanical grinding. At the sites of lower pressure, the chondrocytes proliferate and form the metabolically hyperactive clones which have increased capacity to incorporate tritiated thymidine and radioactive sulfate. The glycosaminoglycan content of articular cartilage, compared to the shamoperated control side, rapidly decreases after operation as suggested by a loss of metachromatic staining and lower per unit weight concentration of uronic acid and hexosamine. In addition to the above changes, the osteophytes quickly develop at the articular margins from the proliferating synovial tissue while underlying bone become thicker and eburnated. These foreign body induced changes in articular morphology and metabolism resemble closely those observed in osteoarthrosis. The present model therefore may prove useful in studying the latter condition.

Animals↗
PubMed1982

The in vitro production of prostanoids by cultured bovine articular chondrocytes.

Bovine articular chondrocytes, cultured as cell suspensions and monolayers, produced prostaglandin (PG) E2 and PGI2 (assayed as 6 keto PGF1 alpha), rather less PGF2 alpha and irregular quantities of thromboxane (Tx) B2. Addition of foetal calf serum to the medium greatly stimulated PG production (a sixfold increase in PGE2 and a twofold increase in 6 keto PGF1 alpha). Prostanoid production by cell suspensions grown in serum-free medium generally plateaued after 24 hours. In the presence of 20% foetal calf serum, prostanoid production in long-term monolayer cultures increased during the first 6 days of culture. Levels of PGE2 and TxB2 then decreased, while 6 keto PGF1 alpha levels remained high. Indomethacin (10(-6)M) inhibited chondrocyte PG production both in the presence and absence of added arachidonic acid (10(-4)M). Prostanoids produced by chondrocytes may play a role in the modulation of cartilage metabolism in vivo.

6-Ketoprostaglandin F1 alpha↗
PubMed1982

Development of the articular cavity in paralyzed chick embryos and in chick embryo limb buds cultured on chorioallantoic membranes.

The development of digital joints of chick embryo paralyzed with dacamethonium bromide and of joints in chick embryo limb buds cultured on chorioallantoic membranes was studied. The digital joints of 45 paralyzed and 40 control embryos and the joints of 37 grafts and 30 control legs were examined histologically. Six preselected grafts were studied by electron microscope. Our results demonstrate that paralysis does not completely inhibit the early stages of joint clefting. In many paralysis does not completely inhibit the early stages of joint clefting. In many paralyzed embryos, small clefts appeared in the periphery and occasionally in the central part of the interzone. Unlike in normal embryos, they rapidly disappeared, inducing fusions across the joints. Early, 2-day paralysis during a period of normal clefting inhibited irreversibly the development of the articular cavity that failed to appear after a cessation of the drug. Paralysis initiated in older embryos caused rapid regression and partial fibrous ankylosis of previously fully differentiated joints. Grafts from 4- to 6-day-old embryos usually failed to develop a full range of skeletal segments. Normal development of skeletal segments occurred in grafts from older donors. The articular cavity failed to develop in almost all grafts. Early cavitation accompanied by characteristic cell changes was found in a few joints. These cellular changes are suggestive of an intrinsic mechanism of early cavitation, but joint motion is required for the full differentiation and maintenance of the joint cavity.

Allantois↗
PubMed1982

[Anatomic incidence of meniscochondrocalcinosis of the knee].

The authors have studied the incidence of menisco-calcinosis (MC) and that of menisco-chondrocalcinosis (MCC) of knee joints of 108 non selected cadavera. The mean age of the subjects was 71.8 +/- 13.8 years. The study was performed by radiographic examination of the menisci and cartilagineous fragments of femoral condyles using high contrast films. The incidence of MC or MCC was found to be 18.5 per cent. It was slightly higher in females (21.5 p. cent) than in males (15.8 p. cent) subjects but this difference failed to reach the level of statistical significance. No positive case was detected before the age of 60 years. For the age groups of: 60-69, 70-79, 80-89 and over 90 years, its incidence was: 11.7; 26.9; 21.2 and 50 (4 subjects out of 8) per cent respectively. Approximately 40 per cent of all positive cases had meniscocalcinosis without associated chondrocalcinosis. No single case of chondrocalcinosis without meniscocalcinosis was observed. Six out of 8 cases with MC calcinosis and 2 out of 12 cases with MCC were unilateral. The external menisci were more frequently and more heavily affected than internal ones. Eighty per cent of the knees affected by either MC or MCC were at the same time associated to an osteoarthrotic lesion compared to 35 p. cent of the knees without MC or MCC matched for age: a result which appeared to be highly significant difference.

Aged↗
PubMed1981

[Effects of different types of collagen on the aggregation and proliferation of bovine articular chondrocytes cultured in vitro].

In the presence of different types of native collagens, particularly type III, isolated chondrocytes do not attach as usual to the plastic walls of culture flasks, but instead aggregate and form nodules and floating pellicules. Furthermore, articular chondrocytes grow differently in the absence or presence of collagen. In the presence of collagen they grow more rapidly and form nodules and large pellicules. Foetal calf and horse serum and bovine synovial fluid contain dialysable factor(s) that inhibit attachment of the cells to the culture walls, but enhance collagen-induced cell aggregation of the chondrocytes.

Animals↗
PubMed1981

Effects of various prostanoids on the in vitro metabolism of bovine articular chondrocytes.

The dose-dependent effects of 9 prostanoids (PGA1, PGA2, PGE1, PGE2, PGF1 alpha, PGF2 alpha, PGD2, PGI2, 6 keto-PGF1 alpha) on metabolism of cultured bovine articular chondrocytes were investigated. Most prostanoids dose-dependently inhibited 35SO4= and 3H-glycine incorporation. At 25 microgram/ml, the inhibitory sequence was A2 greater than or equal to D2 greater than E2= E1 = A1 greater than 6 keto-F1 alpha greater than F1 greater than F2, but sensitivity (lowest dose eliciting inhibition) followed the sequence E2 greater than 6 keto-F1 alpha = F1 greater than A2 = D2 greater than E1 greater than A1. At 25 microgram/ml, PGA2 also inhibited incorporation of 3H-cytidine and 3H-thymidine, but had no significant effect on 3H-glucose or 14C-xylose incorporation. The inhibitory effect of PGA2 was apparent after 30 minutes exposure for 35SO4= and after 60 minutes for 3H-cytidine, and was still present up to 72 hours following incubation in fresh non-PG-containing medium. PGI2 had no significant effect on 35SO4= incorporation but at concentrations below 10 microgram/ml enhanced uptake of 3H-glycine. The PG-induced inhibitory effect was apparently not due to cell damage as indicated by measurement of 3H-glucose metabolism and lactate production.

Alprostadil↗
PubMed1981

Metabolism of human femoral head cartilage in osteoarthrosis and subcapital fracture.

The cell density and incorporation of 35SO4 and 3H-glycine into human articular cartilage from 8 osteoarthrotic and 7 normal (subcapital fracture) femoral heads were studied. It was found that osteoarthrotic cartilage incorporates on a per cell basis about twice as much 35SO4 and 2--5 times as much 3H-glycine as normal cartilage. There was no relationship between the intensity of incorporation and either the location of the cartilage (weight-bearing versus non weight-bearing areas) in normal cartilage or the degree of damage (normal-like, fibrillated, and ulcerated) in osteoarthrotic articular cartilage. In the latter tissue the increased synthetic capacity of the cells seems to be a diffuse rather than a localised process, for it was also found in cartilage from peripheral osteophytes. Histo-autoradiographic studies showed that the osteoarthrotic chondrocytes are metabolically hyperactive all over the femoral head, including wedge-shaped margins of the zone of exposed bone. These results support the hypothesis that much of the articular cartilage from osteoarthrotic femoral heads is of an immature chondroblastic type. It is suggested that de-novo synthesis of articular cartilage occurs during the process of regional remodelling of the femoral head, which would account for the observed hyperactivity.

Aged↗
PubMed1978

Increased metabolic activity of rabbit articular cartilage in vitro.

The metabolic, histochemical and ultrastructural modifications induced in rabbit articular cartilage during in vitro incubation at 37 degrees C, for various periods (10 min to 18 h), using Krebs phosphate-glucose nutrient medium, were studied. It was found that after only 10 min of incubation, the chondrocytes increase their synthesis of matrix macromolecules for, at least, the next 6 h. This was suggested by: 1. Increased incorporation 35S-sulfate and 3H-glycine during the first 6 h of incubation. 2. An intensification of metachromasia, which also spread out into the superficial layer that is normally orthochromatic. Only the most superficial layer corresponding to one or two rows of the cells, retained its staining pattern throughout the incubation; 3. A rapidly acquired abundant rough endoplasmic reticulum, enlarged Golgi area and numerous newly synthesized proteoglycan molecules. This study poses fundamental questions about the mechanisms that regulate matrix synthesis by the chondrocytes.

Animals↗
PubMed1978

Development of the diarthrodial joints in the rat embryo.

The development of appendicular synovial joints of both legs was studied with histological and histochemical techniques in 43 rat embryos aged 12 to 21 days. From this and previous studies, it appears that joints develop by a sequence of cellular events leading to a full expression of the phenotypic characteristics. The classically described stages: cell condensation, three layered mesenchyme, vascular invasion and joint clefting, were chronologically recorded in all joints. The observations relevant to the intra-articular structures, such as joint capsule, menisci and ligaments, were also presented. Previously unreported, cellular aspects were described during joint morphogenesis and their biological significance was discussed. Among these cellular aspects, of particular interest are: a. an early wave of cell necrosis occurring immediately after differentiation of the interzone. Disappearance of necrotic cells is thought to prevent chondrification of this tissue by clearing up the cells with chondroblastic potentialities; and b. a morphologically peculiar type of cells that differentiate alongside, and by the time of, clefting and seem to be related to this process. Thus, the joint clefting appears also to result from a cell-tissue related phenomenon, acting in conjunction with the joint motion, the importance of which has been previously demonstrated.

Animals↗