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Biomedical subjects

M L Zimny

Publications and source records attributed to M L Zimny.

At least 37 records · Page 2Linked to original sources
PubMed1984

Ultrastructure of solitary enchondromas.

Solitary enchondromas obtained from the small bones of the hand were studied with transmission electron microscopy. Three cell types were seen as follows: (1) young looking, active cells with extensive dilated rough endoplasmic reticulum and well defined Golgi and mitochondria; (2) older looking, degenerating cells with dilated rough endoplasmic reticulum, well defined Golgi, glycogen masses, vacuoles containing tropocollagen, lipid and myelin figures; and (3) dying cells showing loss of cell membrane and lysosomal-like bodies. A young chondroblastic cell may try to mature, become a normal chondrocyte that produces normal matrix but it does not succeed and dies. Enchondromal cells are not capable of forming tropocollagen or synthesizing proteoglycans for the matrix.

Bone Neoplasms↗
PubMed1984

Ultrastructure of juxtaglomerular cells correlated with biochemical parameters in a hibernator.

Ultrastructural features of juxtaglomerular cells have been correlated with plasma and kidney analyses from non-hibernating, hibernating and awakening ground squirrels. Juxtaglomerular cells in kidneys from hibernating animals show signs of increased activity. Plasma samples from hibernating animals show a significant increase in magnesium. Kidney analyses from hibernating animals, show glycogen increases and lactate and inorganic phosphate decrease significantly. Adenosine triphosphate remains the same. Maintenance of high-energy phosphates in the hibernating kidney is essential to maintaining sodium transport and osmotic pressure. This coupled with a functional renin-angiotensin system regulates water and electrolyte balance.

Animals↗
PubMed1977

Effects of hibernation on interradicular alveolar bone.

The interradicular alveolar bones of the nonhibernating and hibernating ground squirrels were compared using light and transmission electron microscopy. During hibernation changes occurring in the bone suggest osteocytic osteolysis. Minerals may be mobilized from bone for utilization elsewhere in the body to maintain a minimal metabolic level for survival.

Alveolar Process↗
PubMed1977

A scanning electron microscopic study of the healing of free gingival grafts.

1. Gingiva from the buccal surfaces of the mandibular first molars was grafted to the alveolar mucosa of each of the three premolars in six adult Beagle dogs. Biopsies were made at 0,2,3,4,5,6,7,8,10,14,21 days and at 1 and 6 months. 2. The specimens were fixed in 2% glutaraldehyde, buffered with cacodylate, pH 7.4, rinsed in buffer, dehydrated in graded alcohols, critical point dried, coated with gold palladium alloy and viewed in an AMR-1000 SEM at a tilt of 20 to 25 degrees and an accelerating voltage of 20 kv. 3. The results of this study parallel those reported on the basis of light microscopic studies. The three-dimensional visualization of the graft shows that the external layer of epithelium degenerates and desquamates, except for the basal layer and the structural architecture of the connective tissue is not as well organized. 4. By 21 days the graft is essentially healed, both clinically and histologically.

Animals↗
PubMed1977

Scanning electron microscopy of corneal wound healing in the rabbit.

Corneal lesions 7.5 mm. in diameter were made with an ocular trephine in rabbits. The time periods studied were 0, 30 min., and 1, 2, 4, 8, 16, and 24 hr. At the end of the time period, the cornea was flooded with 4% glutaraldehyde, buffered with cacodylate, pH 7.4, and kept moist until removed. It was then fixed for 24 hr. Half of the sample was dehydrated in graded alcohols, critical-point-dried, coated with gold palladium alloy, and viewed in an AMR-1000 scanning electron microscope at an accelerating voltage of 20 kv. From 0 to 4 hr. cell trauma, debris, and retraction are seen at the margin of the lesion. From 8 to 24 hr. a significant number of polymorphonuclear leukocytes are present over the total surface but in especially large numbers at the wound margin. At 16 to 24 hr. evidence of cell movement is present. Cells show ruffling membranes a decreased number of microvilli, and a few filopodia along the advancing edge.

Animals↗
PubMed1976

Electron microscopic features of lipoprotein-glycosaminoglycan complexes from human atherosclerotic plaques.

Lipoprotein-glycosaminoglycan (GAG) complexes were isolated from fibrous plaque lesions of human aortas and examined by electron microscopy. After fractionation by gel chromatography and ultracentrifugation, both very low density lopoprotein-GAG and low density lopoprotein-GAG complexes showed particles which were mainly 1,000 to 2,000 A in diameter. Occasional large aggregations 3,000 to 10,000 A in diameter were seen after gel filtration and in the very low density lipoprotein fraction of complexes. In general, the complexes were larger than serum very low density lipoprotein and low density lipoprotein, although serum very low density lipoprotein particles ranged from 250 to 2,000 A. In vitro low density lipoprotein-heparin complexes consisted of spherical particles generally 1,000 to 2,000 A in diameter formed by the aggregation and coalescing of smaller low density liproprotein particles in the presence of heparin and Ca2+. These observations support a concept that GAG of the aortic intimal "ground substance" sequester certain serum lipoproteins in a manner similar to in vitro complexing of lipoproteins and GAG in the presence of Ca2+.

Aorta↗
PubMed1975

The surface structure of isolated pancreatic islet cells.

The surfaces of isolated pancreatic islet cells were studied with the scanning and transmission electron microscopes. Islets were isolated from the pancreas of Wistar rats by collagenase treatment and were incubated either in glucose-free medium or in 300 mg% glucose for one hour. Immunoreactive insulin (IRI) in the media of both control and experimental preparations was assayed. Islets were then transferred to 4% glutaraldehyde, buffered with cacodylate, pH 7.4, and prepared for scanning and transmission electron microscopy. Cell masses average 200 mu in diameter. Alpha cells appear pyramidal in shape, are about 8 mu in diameter and appear in groups. Beta cells are round or oval in shape and have an average diameter of 10 mu. Glucose stimulation raised the IRI value tenfold and increased the number of blebs and other surface irregularities per unit area of beta cell surface. Comparison with transmission electron micrographs suggests that the blebs are related to the process of emiocytosis.

Animals↗
PubMed1975

The ultrastructure and biomechanical significance of the tidemark of articular cartilage.

Thirty specimens of human articular cartilage obtained at surgery were examined by scanning electron microscopy to determine the ultrastructure of the tidemark, the junction of the non-calcified and calcified portions of mature articular cartilage. Three distinct variations of the collagen framework of the tidemark were observed: (1) A band of randomly oriented compacted fibrils that appeared to be continuous with those of the non-calcified and calcified zones. (2) A band of flattened fibrils paralleling the undulating surface of the calcified cartilage. (3) A band of perpendicularly oriented fibrils having a distinct continuous transition between the non-calcified and calcified zones, the amount of calcified material applied about the fibrils rapidly increasing as the fibrils entered the calcified zone. The tidemark may serve to provide a tethering mechanism for the relatively flexible and perpendicularly oriented collagen fibrils of the deepest portion of the non-calcified articular cartilage and may prevent them from being sheared at their point of anchorage to the calcified zone. The undulating pattern of the tidemark affords a strong geometric pattern in providing resistance to the shearing action of articulation. Small gaps present in the tidemark may provide pathways for the passage of nutrients into the deep non-calcified zone of articular cartilage from the subchondral bone.

Biomechanical Phenomena↗