Ultrastructure of articular cartilage in experimental immobilization

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Study of Hydrophytes in Some Lentic Water Bodies in West Bengal, India

The physico-chemical characteristics of water, aquatic weeds and bank flora of three water reservoirs located in Krishnagar city (longitude 88°33'E, latitude 23°24'N), West Bengal, India, were studied for a period of 24 months. Altogether 13 genera of aquatic macrophytes belonging to 10 families, and 24 plant species (bank flora) belonging to 16 families were identified in the present investigation. The physico-chemical characteristic of pond water was found to be altered due to these aquatic plants. We have found a general relationship between trophic status of a water body and the aquatic plants present there. We have also found the alteration of water quality due to presence of various aquatic plants. Key words: Physico-chemical characteristics, hydrophytes, macrophytes, bank flora, weeds. DOI: 10.3126/eco.v16i0.3467ECOPRINT 16: 9-13, 2009

Ultrastructural changes in the synovial membrane in lipohaemarthrosis

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SURFACE ULTRASTRUCTURE OF MATURE ADULT HUMAN ARTICULAR CARTILAGE

1. The surface of mature adult human articular cartilage from the knee has been studied by electron microscopy in eleven patients ranging in age from thirty-seven to eighty-three years. The ultrastructural appearance varies from person to person and often from area to area in the same specimen. These variations range from an intact surface to one showing overt fibrillation visible with the light microscope.

2. In areas where the articular surface appears intact the underlying superficial matrix consists of closely packed collagen fibres with only a small amount of interfibrillary ground substance. The collagen fibres show a predominantly tangential orientation in this region of the cartilage. Osmophilic lipidic bodies are sometimes seen in the matrix very close to the joint surface.

3. The appearances under the electron microscope are altered in what is interpreted as an early ultrastructural change in the development of cartilage fibrillation. In the affected areas the collagen fibres show abnormally wide separation by an excessive amount of interfibrillary matrix. Collagen fibres become directly exposed to the joint cavity, and the surface can also show accumulations of finely granular material and sometimes tuft-like projections containing collagen fibres and fine fibrils. At a slightly later stage shallow clefts and steeply sloping curves are apparent at the surface. It is suggested that these various alterations precede the development of overt fibrillation visible under the light microscope.

4. Electron micrographs occasionally show small "blisters" at the articular surface. Electron microscopy has not given evidence of shedding of cells into the joint cavity from non-fibrillated areas of adult human articular cartilage. Cells can, however, sometimes become exposed at the surface in fibrillated areas.

Synovial membrane in experimentally-produced chronic haemarthrosis

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