Twenty percutaneous renal transplant biopsies and 20 removed allografts were investigated ultrastructurally. Most of the detected alterations were of a degenerative or regenerative nature and not specific of rejection. The most interesting phenomenon was the tubulitis, namely, the migration of the interstitial inflammatory cells (IC) through the tubular basement membrane (BM) and the invasion of the tubular epithelium in this way. Tubular epithelial cells (TEC) in the vicinity of IC were often necrotic. The composition of cells invading the tubules corresponded to those infiltrating the interstitium. The distal tubule was more frequently infiltrated than the proximal tubule. The TEC were always in very close contact with the BM. The invading IC were in direct contact with the inner surface of the BM only while passing through it. IC that passed the BM were immediately separated from it by a thin epithelial layer. The tubular ultrastructural changes did not reveal substantial differences between the various rejection types, except for the pronounced thickening and lamellation of the BM in chronic rejection.

Basement Membrane↗

PubMedDate not supplied

Some characteristics of the mesenchymal stem cell of soft tissue tumors.

"Soft tissue tumors" is an unnatural term, used by clinicians and for convenience by pathologists, which unites the neoplasms of mesenchymal origin as opposed to those of the soft epithelial tissues. Not included are the reticuloendothelial system, glia and supporting tissues. The mesenchymal stem cell, the cell of the embryonal connective tissue, exhibits in man and mammals the most pronounced embryonal potential. A restricted comparison to the embryonal potential in larval and pupal cells of invertebrates, such as in hemi- or holometabolic insects and to meristematic cells in vascular plants is justified. The great embryonal potential may explain why the mesenchymal stem cell, at present a hypothetical unit, is able to transform and differentiate into the connective tissue as such, the muscular, supporting and hematogenic tissues. The musculature comprises the bulk of the mammal's body weight. The development of the normal ontogenetic specialization as well as especially those differentiations leading to soft tissue tumors are comparatively shown in this publication and placed in the framework of vertebrate and invertebrate animals with true tissues.

Animals↗

PubMedDate not supplied

Neoglycoprotein binding to normal urothelium and grade-dependent changes in bladder lesions.

Chemical conjugation of carbohydrate derivatives to a labelled carrier protein makes it possible to monitor the presence of specific sugar-dependent binding to routinely processed tissue sections. Different levels of cytoplasmic staining were observed in normal urothelium for the applied probes that expose a beta-D-galactoside, alpha- or beta-N-acetyl-D-galactosaminide, beta-N-acetyl-D-glucosaminide, alpha-D-mannoside, alpha-L-fucoside or a-D-glucoside, respectively. These moieties are crucial parts of the recognition sites in cellular glycoconjugates for plant lectins. The extent of staining invariably increased from the basal to the luminal cell layer. No nuclear staining was observed. Within the 18 cases of bladder lesions studied, the appearance of nuclear staining was characteristic of transitional cell carcinoma, its correlation to the histologic grade being dependent on the type of neoglycoprotein. Cytoplasmic staining revealed at least two patterns of grade-dependent variations, namely rather constant expression for lactose-mannose-, fucose- and maltose-specific sites and an initial increased followed by a loss of binding activity at the highest level of cellular atypia for the other three types of probe. Intratumoral heterogeneity was especially visible in tumors of this group. Interestingly, the known positive correlation of presence of the Thomsen-Frieden rich antigen with the level of cellular atypia, monitored with peanut agglutinin, could be extended to the expression of respective receptor sites, which was experimentally feasible due to the synthesis of this disaccharide structure and its immobilization to the carrier protein.

Arachis↗

PubMedDate not supplied

Some observations on Ornithodoros parkeri from Monterey County and its associated borrelia infection.

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Animals↗