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Biomedical subjects

A L Griffith

Publications and source records attributed to A L Griffith.

At least 19 recordsLinked to original sources
PubMed1987

Characterization of feline omentum lipids.

Feline omental lipid extracts, previously reported to be angiogenic in the cornea of rabbits, were fractionated and the major lipid components characterized. Approximately 97% of the chloroform/methanol extract consisted of triglycerides containing primarily 16:0, 18:0, 18:1 and 18:2 fatty acids. Trace quantities of free fatty acids, cholesterol, di- and monoglycerides were also detected. The phospholipid fraction, obtained by solvent partition and Unisil column chromatography and characterized by high performance liquid chromatography (HPLC)-mass spectrometry, was found to consist of phosphatidylcholine, sphingomyelin, phosphatidylethanolamine and phosphatidylserine. The neutral glycolipids, isolated by solvent partition and Unisil column chromatography and identified by high performance thin layer chromatography and HPLC of their perbenzoylated derivatives, were found to consist of glucosyl- and galactosylceramides, galabiosylceramide, lactosylceramide, globotriaosylceramide and globotetraosylceramide. The complex glycolipid fraction, obtained from Folch upper phase solvent partition, was found to consist primarily of Forssman glycolipid and gangliosides GM3 and GD3. Smaller amounts of GM1 and other unidentified gangliosides were also present.

Animals↗
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↗
PubMed1984

Lipid angiogenic factor from omentum.

Placing the omentum on the brain surface by surgical transposition or transplantation will result in the development of numerous neovascular connections between these two structures. This phenomenon occurs even in the absence of cerebral ischemia, which raised the question as to whether an angiogenic factor was causing the response. A lipid material obtained from the omentum contains a potent angiogenic factor extractable in a chloroform-methanol solvent mixture. Angiogenesis created by this material was observed in the rabbit cornea after only a single injection of the substance. The angiogenic material obtained from the omentum is abundant in supply. This important characteristic offers promise for the purification and identification of its structure, which should allow for extensive animal and clinical studies dealing with the development or inhibition of angiogenesis.

Adipose Tissue↗
PubMed1983

Alteration of the electrophoretic mobility of human peripheral blood mononuclear cells following treatment with dimethyl sulfoxide.

Studies have been conducted to determine the effects of DMSO and freezing on the electrophoretic distribution of peripheral blood mononuclear cells. Sodium [51Cr]chromate was used to label the cells, and the distributions of cell number and cell-associated radioactivity were determined. Cells treated with DMSO had a narrower distribution of electrophoretic mobilities when compared with those not treated. DMSO-treated cells also demonstrated a more homogeneous distribution of radioactivity relative to the cell distribution than did the nontreated cells. The freezing of DMSO-treated cells did not result in any additional alteration of electrophoretic pattern compared to DMSO treatment alone. Analysis by linear categorization techniques indicated that the DMSO-treated and nontreated cells were completely distinguished by their electrophoretic behavior.

Blood Preservation↗
PubMed1980

Gravity sedimentation analysis of human blood leukocytes.

A new method of sedimentation analysis of human blood leukocytes is described. Platelets, lymphocytes, monocytes, and polymorphonuclear cells isolated from normal human peripheral blood have been analyzed alone and in mixture by gravity sedimentation, employing a computerized scanning instrument. All four classes could be clearly resolved from each other exhibiting sedimentation velocities of 0.06 +/- 0.00, 1.04 +/- 0.11, 1.27 +/- 0.15 and 1.89 +/- 0.21 x 10(-4) cm/s, respectively, at 37 degrees C in a 2.5--6.25% Ficoll gradient in Medium 199. Less than 10(6) cells can be used for analysis. Possible applications of the method are discussed.

Blood Platelets↗
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↗
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↗
PubMed1976

Electrophoretic separation of radioisotopically labeled mouse lymphocytes.

A new preparative method is described for the separation and direct electrophoretic comparison of the distribution profile of radioisotopically labeled cells. The cell populations to be compared are labeled separately with different radioisotopes (e.g., 51Cr and 99mTc) and mixed. The cell mixture is subjected to density gradient electrophoresis and the distribution of each radioisotope in the collected fractions is ascertained by differential gamma counting. In the case of uniform label uptake by the cells in each distribution, the radioactivity counts represent cell frequency. Nonuniform labeling allows useful comparisons only in terms of relative mobility distribution. Model experiments performed with 51Cr- and 99mTc-labeled mouse thymocytes and spleen cells are in general agreement with mobility distribution results obtained previously by free flow electrophoresis.

Animals↗
PubMed1975

Size and charge heterogeneity of rat tissue ferritins.

Ferritins purified from horse spleen and from rat liver, kidney, heart and hepatoma were analyzed by quantitative polyacrylamide gel electrophoresis. From the migration characteristics of these ferritins at several gel concentrations, Ferguson plots were constructed and the molecular sizes and charges (apparent valences) together with their statistical variability were obtained by applying Rodbard computer programs to the data. Finally, ellipses were drawn describing the 95% confidence limits of these data for size and charge and were used to identify those ferritins that differed in size and/or charge. By these criteria, many of the tissue ferritins were differentiated from one another in terms of their molecular size and/or charge. Among the various tissue ferritin monomers, the molecular sizes were essentially similar (420 000-490 000) except for the two heart ferritins which were larger (530 000 and 626 000, respectively). However, the estimated charges on rat liver, kidney and hepatoma monomers (30-38 net protons per molecule) differed from that of spleen monomer (51 net protons per molecule) while the larger rat heart ferritin also had a greater charge (83 net protons) than the smaller (40 net protons). Apoferritins prepared chemically by removal of iron from the holoferritins had migration properties indistinguishable from the parent holoferritins. The migration properties of minor (dimeric) ferritin bands on the gels were compared with those of the monomer bands. The molecular sizes of the minor bands were larger than those of the major bands, and were not inconsistent with a doubling in size. However, charge differences varied, being either similar for major and minor forms (spleen ferritin), approximately twice for the minor form (rat hepatoma ferritin) or five times greater for the minor form (rat liver ferritin). These differences in behavior were confirmed by using minimally sieving gels, on which the major bands of horse spleen ferritin failed to separate whereas those of rat liver ferritin were readily separable. It is concluded that dimers of ferritins from different tissues may associate in different ways.

Animals↗