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Biomedical subjects

B J Panner

Publications and source records attributed to B J Panner.

At least 37 records · Page 2Linked to original sources

Bilateral cervical transplantation of canine kidneys for study of canine renal preservation.

Bilateral cervical autotransplantation of canine kidneys is described for comparative study of renal preservation techniques. Data are obtained from kidneys preserved by (1) initial intravascular flushing with modified Collins' C3 solution (Ursol) followed by cold storage, and (2) pulsatile perfusion (MOX 100). Preharvest condition of the donor and ischemia times are identical, thus eliminating major sources of potential data variation. Renal function studies performed at periodic intervals demonstrated better initial function for machine preservation but no difference after one to two-month period.

Animals↗

Spontaneous remission of the nephrotic syndrome in diabetic nephropathy.

A 28 year old woman, with diabetes since age 18, had the nephrotic syndrome, hypertension and renal insufficiency. The initial renal biopsy specimen revealed diffuse glomerulosclerosis with early nodular changes. After an initial decline in renal function, her creatinine clearance progressively improved and has remained normal. Within 2 years she had a spontaneous remission of the nephrotic syndrome despite the presence of more pronounced nodular glomerular lesions. Although the renal hemodynamic functions were normal, certain tubular functions were impaired. Since we found no etiology for the nephrotic syndrome other than diabetic glomerulopathy, the complete remission of the nephrotic syndrome and improvement in renal function were very unusual events.

Adult↗

Locus and state of aggregation of myosin in tissue sections of vertebrate smooth muscle.

Structures with the characteristics of molecular myosin were identified by electron microscopy in tissue sections of vertebrate smooth muscle. No thick filaments of myosin were found regardless of preparative procedures, which included fixation at rest and in contraction, glycerine extraction, and storage at low pH prior to fixation. Absence of thick myosin filaments and presence of what appear to be myosin molecules is in accord with conclusions based on X-ray diffraction (3, 12) and birefringence data (4) from living smooth muscles at rest and in contraction. Explanations are provided for appearances thought by others (6, 20, 21) to represent thick myosin filaments. Our present observations are in accord with the model for smooth muscle contraction which we have previously proposed (1).

Animals↗

Studies on ultrastructural identification and distribution of protein-polysaccharide in cartilage matrix.

Previous reports on the ultrastructure of cartilage matrix have described fibers, amorphous ground substance and, in some instances, dense matrix granules. The fibers are presumably collagen, but the nature of the granules is unknown. The primary purpose of this study has been to investigate the ultrastructure of cartilage matrix ih chick embryos with particular emphasis on the distribution and composition of these granules. In matrix of the zone of articular cartilage, mature collagen fibers can be seen but granules are not present. In matrix of all other zones of cartilage, fibers are smaller and granules are present. When the matrix of epiphyseal cartilage is compared to that of the zone of hypertrophic cells, fibers are similar but the granules in the latter zone are larger and more numerous. The granules in both zones were digested by hyaluronidase and positive to colloidal iron staining. Chemical analyses of cartilage from these zones indicate the hexosamine and radiosulfate content of the zone of hypertrophic cells to be higher than that of the zone of epiphyseal cartilage. The increased hexosamine was shown by column chromatography to be principally sulfated mucopolysaccharide, thereby indicating a direct correlation between size and number of granules and sulfated mucopolysaccharide content in the two zones. These data and the results of the electron microscopic histochemical studies are consistent with the concept that the granules in cartilage matrix contain acidic mucopolysaccharide.

Animals↗

Filament ultrastructure and organization in vertebrate smooth muscle. Contraction hypothesis based on localization of actin and myosin.

Using a variety of preparative techniques for electron microscopy, we have obtained evidence for the disposition of actin and myosin in vertebrate smooth muscle. All longitudinal myofilaments seen in sections appear to be actin. Previous reports of two types of longitudinal filaments in sections are accounted for by technical factors, and by differentiated areas of opacity along individual filaments. Dense bodies with actin emerging from both ends have been identified in homogenates, and resemble Z discs from skeletal muscle (Huxley, 1963). In sections, short, dark-staining lateral filaments 15-25 A in diameter link adjacent actin filaments within dense bodies and in membrane dense pataches. They appear homologous with Z-disc filaments. Similar lateral filaments connect actin to plasma membrane. Dense bodies and dense patches, therefore, are attachment points and denote units analogous to sarcomeres. In glycerinated, methacrylate-embedded sections, lateral processes different in length and staining characteristics from lateral filaments in dense bodies exist at intervals along actin filaments. These processes are about 30 A wide and resemble heavy meromyosin from skeletal muscle. They also resemble heads of whole molecules of myosin in negatively stained material from gizzard homogenates. Intact single myosin molecules and dimers have been found, both free and attached to actin, even in media of very low ionic strength. Myosin can, therefore, exist in relatively disaggregated form. Models of the contraction mechanism of smooth muscle are proposed. The unique features are: (1) Myosin exists as small functional units. (2) Movement occurs by interdigitation and sliding of actin filaments.

Animals↗