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Biomedical subjects

N Catsimpoolas

Publications and source records attributed to N Catsimpoolas.

At least 19 recordsLinked to original sources
PubMed1989

Omental angiogenic lipid fraction and bone repair. An experimental study in the rat.

A lipid material extracted from the omentum has previously been shown to contain a potent angiogenetic activator (20), capable of creating intense vasoproliferation in traumatized tissues (19). This study was undertaken to analyze the efficacy of local administration of this omental lipid fraction on osseous vascularization and bone repair. An osteoperiosteal segmental femoral defect in the rat was replaced by a demineralized allogenic bone graft exposed to continuous local delivery of omental lipid via an implanted miniosmotic pump. Saline solution delivered in the same way served as a control. Neovascularization and bone formation in the transplant were quantitatively evaluated by means of dynamic radioisotopic bone imaging, radiographic photodensitometry, microangiography, and biomechanical testing. Compared with the control group, the omental lipid angiogenic fraction-treated specimens showed an 80% overall increase (p less than 0.001) in bone density as well as a twofold increase (p less than 0.001) in regional blood perfusion, maximal at 2 weeks following surgery. At 12 weeks, biomechanical testing demonstrated significantly higher union rate (p less than 0.05) and strength (p less than 0.01) in the treated specimens as compared with the controls. These data demonstrate that the omental lipid fraction factor has potent angiogenic properties that enhance bone blood perfusion and bone regeneration.

Absorptiometry, Photon↗
PubMed1986

Increased vascular perfusion after administration of an omental lipid fraction.

Recently, it has been reported that a lipid material is present within the omentum which has potent angiogenic activity. In the report being presented herein, the omental material was injected intramuscularly in the area of a standardized wound and at a site distant from the wound. Control animals were injected in a comparable manner using saline solution. The omental lipid material resulted in increased vascular perfusion in the wound regardless of whether the material was injected locally or remotely as measured by in vivo nuclear imaging techniques using tagged erythrocytes labeled with Technetium (Tc-99m). The ability to demonstrate that an omental lipid fraction can cause increased vascular perfusion has become possible because the omental lipid material is abundant in supply and relatively simple to prepare in large quantities.

Angiogenesis Inducing Agents↗
PubMed1979

Cytotaxins after the sedimentation behavior of human granulocytes.

Human granulocytes from the peripheral blood of healthy donors were subjected to transient gravity sedimentation analysis in Ficoll density gradient columns (37 degrees C) containing different concentrations of Escherichia coli endotoxin-activated serum and medium 199. A dramatic serum concentration-dependent dispersion of the cells based on changes in sedimentation velocity was observed as a function of time, using a new optical scanning instrument. The phenomenon was virtually abolished in the presence of cytochalasin B, a known inhibitor of cellular chemotaxis. The width (second statistical moment) of the sedimenting cell distribution increased in a sigmoid fashion as a function of time regardless of cytotaxin concentration. This indicates that a slow and nonlinear response of the granulocytes to the cytotaxins occurs. This new kinetic method should be useful in examining an alternate manifestation of the chemoresponsiveness of phagocytic cells and of cell interactions in general.

Bacterial Toxins↗
PubMed1979

Separation of T and B lymphocytes from various mouse strains by density gradient electrophoresis.

T and B mouse spleen lymphocytes were separated by density gradient electrophoresis on the basis of their surface charge. In all strains examined, the T lymphocytes were found in the high mobility fractions and the B in the low. The T and B cells were separated completely in most fractions, with some overlapping in the middle. Significant differences were found in the electrophoretic distribution profiles between the strains: C57BL/6j, C57BL/10j, (BALB/cXC57BL/6j)F1, and all the following: B6.C-H-2d/cBy (congenic to C57BL/6j), BALB/c, CBA/H/T6j, C57BL/10Sn, and C3H. The C57BL/6j and the (BALB/cXC57BL/6j)F1 cells appear more heterogeneous as far as electrophoretic mobility is concerned. Almost all the other strains give two major peaks. Moreover, the high mobility areas are less populated in the C57BL/6j and the (BALB/cXC57BL/6j)F1 animals than in all the others. The above differences were found consistently when cells prepared by different methods were electrophoresed. It is concluded that the surface charge of lymphocytes may be genetically determined. Possible dependency on the H-2 complex or non-H-2 areas is discussed.

Animals↗
PubMed1979

Separation of rat T and B lymphocytes by density gradient electrophoresis.

Density gradient electrophoresis has been employed for the preparative separation of T and B lymphocytes from rat spleen and peripheral blood. The high mobility cells were found to be predominantly T lymphocytes, as determined by their response to phytohemagglutinin and the relative absence of immunoglobulin-positive cells. The low mobility cells were predominantly B cells, as determined by the high percentage of immunoglobulin-positive cells and the total lack of response to PHA, an exclusive T cell mitogen. A better separation of peripheral blood T and B lymphocytes was achieved than with spleen T and B cells.

Animals↗
PubMed1977

Structural features of rat cardiac ferritins.

Ferritin extracted from rat heart containes two species separable by gel electrophoresis. These were purified and examined for structural characteristics. As in gel electrophoresis, cardiac ferritin preparations yielded only two bands on isoelectric focusing in gels, with pI values of 4.6 and 4.8. After separation by preparative electrophoresis, the two species were found to have a different amino acid composition from each another and from liver ferritin. Similarly, peptide maps showed several components not found in liver ferritin. On dissociation and electrophoresis with sodium dodecyl sulfate, heart ferritins were found to contain subunits of the same sizes as in other rat ferritins but also some larger components. Since cardiac ferritins have apparent molecular weights greater than those of other ferritins, it is concluded they probably contain more subunits, and possibly some of larger size not present in ferritins of other tissues.

Amino Acids↗
PubMed1976

The effect of cryogenic storage on human erythrocyte membrane proteins as determined by polyacrylamide-gel electrophoresis.

A study was conducted to determine the effects of freezing on the major membrane proteins of isolated human erythrocyte membranes. Membranes in low or normal ionic strength medium were frozen at slow or fast freezing rates. The membrane protein composition and elution of proteins from the membranes were studied utilizing polyacrylamide-gel electrophoresis in a sodium dodecyl sulfate or an acetic acid-urea-phenol solvent system. Neither a change in the composition of the membrane proteins nor any elution of membrane protein during freezing and thawing was observed. The data indicate that any human erythrocyte membrane damage during freezing and thawing was not related to a change in major membrane protein composition. Human red cell membranes were stable at --80 or --196degreesC in the absence of a cryoprotective agent.

Blood Preservation↗
PubMed1976

Density gradient electrophoresis of mouse spleen lymphocytes: separation of T and B cell fractions.

Preparative electrophoresis in an isotonic Ficoll--sucrose density gradient has been employed for the separation of mouse (C57Bl/6J) spleen lymphocyte subpopulations. The separated cells were pooled into six fractions according to their relative position (Rp) within the total cell distribution. In general, the high mobility cells were identified as T lymphocytes. These cells exhibited immunofluorescence upon reaction with fluorescein isothiocyanate-conjugated mouse anti-theta globulin and responded in vitro to phytohemagglutinin stimulation. The low mobility cells were activated in vitro by E. coli lipopolysaccharide and showed immunofluorescence upon reaction with fluorescein isothiocyanate-conjugated anti-mouse Ig which is typical of mouse B lymphocytes. Both T and B cells were completely isolated from each other in certain fractions of very high and very low mobility, respectively. Overlapping of the two distributions was observed in the intermediate mobility fractions. The method which utilizes an inexpensive commercially available apparatus should be useful for the preparation of other lymphocyte subpopulations differing in surface charge.

Animals↗