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Biomedical subjects

L Glasser

Publications and source records attributed to L Glasser.

At least 37 records · Page 2Linked to original sources
PubMed1987

Experimental studies on the role of alkyl lysophospholipids in autologous bone marrow transplantation.

The selective cytocidal effect of alkyl lysophospholipids against neoplastic cells while sparing normal cells make these ideal candidates for purging leukemic cells from bone marrows obtained during remission. To test the feasibility of such an approach, a murine model and an in vitro human cell model were developed. In the murine system a mixture of normal bone marrow cells and WEHI IIIB myelomonocytic leukemic cells was incubated with varying doses of 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine (ET-Me) for 24 hr before being injected into tail veins of lethally irradiated Balb/c mice. At doses of 20 and 100 micrograms/ml, long-term survivors were noted. The additional steps of freezing and thawing following incubation resulted in significantly longer survival with doses of 10 to 50 micrograms/ml, but were toxic to marrow stem cells at 100 micrograms/ml. In the in vitro model, normal marrow progenitor cells and leukemic cells (the promyelocytic cell line HL60) were exposed to varying concentrations of ET-Me for 1 and 4 hr alone or mixed, and clonogenicity was assayed by colony formation in semisolid medium during 7-14 days' incubation. At doses up to 100 micrograms/ml exposed for 4 hr normal progenitor cells were spared and HL60 colonies eliminated. Other phospholipids analogues were less effective in eliminating leukemic cells, but spared normal progenitor cells. A survey of fresh leukemic cells found varying degrees of sensitivity to ET-Me, indicating the need for testing a variety of compounds. These studies clearly indicated the potential usefulness of alkyl lysophospholipid compounds in selectively purging leukemic cells from remission marrows for autologous bone marrow transplantation.

Animals↗
PubMed1987

Bordetella pertussis adenylate cyclase: effects of affinity-purified adenylate cyclase on human polymorphonuclear leukocyte functions.

Affinity-purified adenylate cyclase (AC) of Bordetella pertussis, free of contaminating pertussis toxin, was demonstrated to have biological effects on human polymorphonuclear leukocytes (PMN). AC at doses of 25 and 50 micrograms/ml increased intracellular cAMP levels in the phagocytes 7.6- to 23.5-fold, respectively, above basal levels. AC inhibited PMN chemiluminescence, chemotaxis, and superoxide production in a dose-dependent manner. The 50% inhibitory dose for chemotaxis and chemiluminescence was 36.5 micrograms/ml; for superoxide generation it was 71.0 micrograms/ml. Although these PMN metabolic functions were impaired, no effect on phagocytic activity was observed.

Adenylate Cyclase Toxin↗
PubMed1987

Effect of cryopreservation on purging of leukemic marrow with alkyl-lysophospholipids.

Alkyl-lysophospholipids (ALP) are reported to be selectively cytotoxic to neoplastic cells and have been demonstrated to be an effective purging agent for autologous marrow transplantation in a murine model, WEHI-3B. We studied the effect of in vitro treatment of normal bone marrow cells with ALP and of cryopreservation on spleen colony-forming units (CFU-s) in irradiated, syngeneic Balb/c mice. We found that exposure of cells to doses of ALP of 5 or 20 micrograms/ml followed by cryopreservation had no effect on CFU-s, but that a dose of 100 micrograms/ml was toxic. A simulated remission marrow was prepared by mixing normal murine bone marrow cells with WEHI-3B myelomonocytic leukemic cells to give a 1%-2% concentration of leukemic cells. These were exposed to 0- to 100-micrograms/ml concentrations of ALP for 24 h, cryopreserved, thawed, and injected into the tail veins of lethally irradiated syngeneic mice, and survival measured. It was found that concentrations of ALP from 10 to 50 micrograms/ml resulted in long-term disease-free survivors. These results established the fact that cryopreservation did not alter the effectiveness of ALP in purging marrows of residual leukemic cells.

Animals↗
PubMed1987

Functional differentiation of normal human neutrophils.

In the past differentiation of human neutrophils has been defined by morphology, cytochemistry, or surface markers. In our experiments we have sequenced the various events that occur during the functional differentiation of the normal human neutrophil and have also examined some of the functional properties in relationship to surface markers and biochemical events. Granulocytes were obtained from the bone marrow and blood of hematologically normal individuals. Cells were separated into different stages of maturation by their physical properties using counterflow centrifugal elutriation and density gradient separation. Three cell fractions were obtained that were enriched for either immature myeloid cells, band neutrophils, or segmented neutrophils. Since the enriched fractions were not entirely pure, methodologies for functional assays were chosen that allowed cytologic evaluation of the functional capacity of each cell type. The criteria used to classify the stages of differentiation included both morphology by light microscopy and DNA labeling with tritiated thymidine. Various neutrophilic properties were studied: Fc receptors, complement receptors (CR1, CR3), phagocytosis of both live and dead opsonized Staphylococcus aureus, microbial killing of S aureus, NBT dye reduction after cellular stimulation with endotoxin, and chemotaxis. Our results indicate that the functional properties of the neutrophil appear in a distinct order. The sequence for the functional differentiation of the human neutrophil appears to be the following: Fc receptors----immune phagocytosis----complement receptors----oxygen-independent microbial killing----oxygen-dependent microbial killing----chemotaxis.

Bacteriolysis↗
PubMed1986

Binding isotherms by continuous-flow dynamic dialysis.

The classical dynamic dialysis technique for the determination of a protein-ligand binding isotherm has been modified by the introduction of a flow cell in which the dialysate on the sink side of the membrane is continuously eluted with a constant flow of eluting buffer and its ligand concentration measured. This new experimental method is termed continuous-flow dynamic dialysis (CFDD). A transfer function procedure for extracting the binding isotherm from the dialysis data is described. This is a more general technique (requiring only a verifiable assumption of linearity) than that previously used, in which the system was modelled using Fick's first law and which relied on the establishment of quasi-steady state conditions across the membrane. The present analysis uses the Laplace transform to effect deconvolution of the impulse response function of the cell from the dialysis data and, using a Fourier series approach, directly yields numerical data representing the free ligand concentration in equilibrium with the protein-ligand complex. The protein-ligand binding isotherm is obtained in parametric form, with time as the parameter.

Journal Article↗
PubMed1986

Effects of isokinetic training on the rate of movement during ambulation in hemiparetic patients.

The purpose of this study was to determine the effects of isokinetic training on the rate of movement during ambulation in hemiparetic patients. Ten male and 10 female subjects, aged 40 to 75 years, participated in the study. The 20 hemiparetic subjects were assigned randomly to either a control group or an experimental group. All of the subjects participated in a conventional therapeutic exercise program and gait training. The experimental group also received isokinetic training on the Kinetron exercise machine as part of their program. Functional ambulation profile tests were administered to each subject before and after the five-week experimental period. All of the subjects showed improvement in the rate of ambulation and in overall ambulation performance. The differences in ambulation times and functional ambulation profile scores between the two groups were shown to be insignificant.

Adult↗
PubMed1986

An ultrastructural morphometric analysis of platelet giant and fusion granules.

Our purpose in this study was to establish ultrastructural morphometric criteria that can be used to define pathologic giant and fusion platelet granules and to determine whether patients with neoplastic myeloproliferative disorders (MPD) can be distinguished from other patients. We have morphometrically analyzed 2,391 giant and fusion granule profiles from 46 patients with neoplastic MPD, 127 other diseased control subjects, and 30 normal subjects using a computerized image analyzer. The largest granule profile observed in normal subjects had an area of 0.51 mu 2 and a perimeter of 3.21 mu. The most irregularly shaped of the large granule profiles photographed from normal subjects had a form factor (FF) value of 0.31. FF values indicate the degree of deviation of a given granule contour from a circle and is expressed by the formula 4 pi A/P2. A pathologic granule profile was then defined as a granule that exceeded any of these limits. Fifty-seven percent of the patients with neoplastic MPD were determined to have abnormal platelet granule profiles using the aforementioned morphometric criteria. It was determined, however, that morphometrically defined giant- and fusion-type granule profiles were nonspecific and were also found in 20% of the other diseased patients with no clinical evidence of an underlying neoplastic MPD. Morphometry has allowed us to define the upper limits of normal for the area and perimeter of individual platelet granules. Morphometrically defined giant fusion granules were determined to be more prevalent in the neoplastic MPD group, but because of their nonspecificity, may only have diagnostic significance for the individual patient in specific clinical settings. The pathogenesis of platelet fusion granules is discussed.

Blood Platelets↗
PubMed1985

Surface features of human natural killer cells and antibody-dependent cytotoxic cells.

The purpose of the present study was to examine the surface features of purified large granular lymphocytes (LGLs) (natural killer (NK) cells, antibody-dependent cytotoxic lymphoid (ADCL) cells, K-cells, Fc gamma (+) third population (non-T, non-B) lymphoid cells, T gamma cells) by scanning electron microscopy (SEM) and to compare their surface features with granulocytes, monocytes and Fc gamma (-) lymphoid cells that were all fixed for SEM under identical conditions. We have determined that 72-80% of LGLs enriched by rosette formation with sensitized erythrocytes or using Percoll gradients, have a complex microvillous surface (CMS) pattern identical to that of lymphocytes. The LGL fraction appears by SEM to represent a morphologically homogeneous population of cells. Monocytes prepared for SEM under identical conditions had distinct surface folds and granulocytes displayed numerous broad-based ridge-like profiles. The majority of lymphoid cells in an unfractioned population have a CMS pattern when incubated at room temperature (25 degrees C) before fixation, and a sparse microvillous surface (SMS) pattern when incubated at body temperature (37 degrees C). Ficoll-Hypaque (FH) also had a direct effect on the cell surface pattern. Over half of the unfractionated lymphoid cells displayed a CMS pattern after cells were washed free of FH and incubated at 37 degrees C before fixation. The CMS pattern is therefore not unique to LGLs but can be produced by the surface alteration of non-LGLs found in unfractionated buffy coat and mononuclear fractions. The interactions between LGLs and sensitized erythrocytes in an antibody-dependent cytotoxic assay system, and LGLs and K562 target cells in an NK assay system, were also examined. This is the first report that describes the surface features of human LGLs interacting with K562 target cells in an NK assay system. The LGL populations studied by SEM were determined to have a high percentage of Leu-11(+) and Leu-7(+) cells. These same population were also shown to have high antibody-dependent cytotoxicity and NK activity using the 51Cr release assay.

Cell Fractionation↗
PubMed1985

Liquid preservation of human neutrophils stored in synthetic media at 22 degrees C: controlled observations on storage variables.

The purpose of this study was to use a chemically defined medium to identify essential substances and optimal conditions for the liquid storage of neutrophils at 22 degrees C. Several commercially available synthetic media were evaluated: L-15, McCoy's 5a, M199, minimum essential medium, Dulbecco's MEM, NCTC135, and RPMI 1640. Proteins, glucose, pH, and neutrophil concentration were systematically studied. Neutrophils were harvested by centrifugal cell separators or phlebotomy, and their maintenance was evaluated by monitoring cell counts, dye exclusion, phagocytosis, bacterial killing, and chemotaxis. Neutrophils stored equally well in all synthetic media except L-15; however, chemotaxis was poorly maintained in synthetic media as compared with autologous plasma. RPMI 1640 was arbitrarily selected as a basal medium to evaluate storage variables. RPMI 1640 supplemented with albumin to a concentration of 1% improved chemotaxis and was equivalent to plasma as a storage medium with regard to the in vitro functions tested. Cohn fractions IV-1, IV-4, and gamma globulin were not effective substitutes for albumin. Glucose is essential for neutrophil storage; its absence from the medium correlated with poor cell function. Optimal glucose requirements depend on the cell concentration. High glucose concentrations were toxic to neutrophils; at 1,000 mg/dL, chemotaxis was depressed by 58%. Glucose utilization was dependent on the initial pH of the medium and on the cell concentration. A wide range of hydrogen ion concentrations was tolerated, and the optimum pH range was 7.2 to 7.8. Cell concentration is an important variable because it affects the pH of the medium as well as glucose utilization.

Adult↗
PubMed1984

Purging murine leukemic marrow with alkyl-lysophospholipids.

Autologous bone marrow transplantation is potentially curative in the treatment of acute leukemia if residual leukemic cells in the marrow can be eliminated prior to transplantation. We studied the purging effects of a synthetic alkyl-lysophospholipid (ALP) on marrow containing leukemic cells from a transplantable myelomonocytic leukemia (WEHI-3B) in BALB/c mice. Simulated remission bone marrow containing 2% leukemic cells treated in vitro with 20 and 100 micrograms/mL of ET-18-OCH3 (1-octadecyl-2-methyl-sn-glycerol-3-phosphocholine) significantly prolonged survival of lethally irradiated transplanted recipients. At a dose of 100 micrograms/mL, 88% of the mice survived for the duration of the experiment (approximately five months). Autopsies showed that 25% of these survivors had microscopic evidence of leukemia. Thus, in vitro treatment of marrow eliminated leukemic blasts and spared sufficient normal stem cells to allow hematologic reconstitution. The effect of ET-18-OCH3 is not entirely selective for leukemic cells. A spleen colony assay showed that ALP has some cytotoxic effect on normal hematopoietic stem cells.

Animals↗
PubMed1983

New ultrastructural observations: parallel tubular arrays in human T gamma lymphoid cells.

T gamma cells are E-rosetting cells bearing Fc receptors for IgG (E+, Fc gamma + cells). Third population (non-T, non-B) lymphoid cells are also Fc gamma + cells and contain unique inclusions called parallel tubular arrays (PTA). Although T gamma cells and third population lymphoid cells should belong to a similar population of cells, previous ultrastructural studies on purified T gamma cells have failed to reveal the presence of PTA. In this study, we have unequivocally demonstrated PTA in the majority of T gamma cells using simple rosetting techniques. A total of 76 EA hu-rosettes and 108 EA ox-rosettes prepared from an E+ enriched fraction (using sheep erythrocytes as marker particles) were directly examined by electron microscopy. PTA were found in 87% of the EA hu-rosettes and 82% of the EA ox-rosettes. Ammonium chloride, commonly used in other laboratories to lyse erythrocytes during the purification procedure was found to cause a marked decrease in the number of ultrastructurally distinct PTA profiles. In contrast, hypotonic lysis had no effect on cellular ultrastructure. This study showed for the first time that T gamma cells are ultrastructurally similar to other Fc gamma + lymphoid cells and contain PTA as a distinct marker. The significance of our findings to the basic function of this E+ Fc gamma + lymphoid population is discussed.

Ammonium Chloride↗
PubMed1983

Leukemic cells as probes for sequential functional differentiation of the human granulocyte.

The purpose of this study was to sequence the functional properties of the neutrophil during maturation, using leukemic cells as experimental probes. Twenty-nine cases of acute leukemia, derived from granulocytic precursors, were studied. The functional tests that were evaluated included phagocytosis, bactericidal activity, random locomotion, and chemotaxis. These functional properties were correlated with Fc receptors and the stimulated nitroblue tetrazolium dye reduction test. The results indicated that the various functions of the neutrophil are acquired sequentially rather than concurrently. It is postulated that the sequence of functional differentiation is: phagocytosis leads to microbial killing leads to random locomotion leads to chemotaxis.

Adolescent↗
PubMed1982

Liquid storage of granulocytes.

The length of time that neutrophils can be stored is the most limited of any of the formed elements of the blood that are presently transfused clinically. Several methods have been used to evaluate the storage of granulocyte concentrates. These include cell counts, cell volume, morphology, dye exclusion, oxygen consumption, hexose monophosphate shunt activity, nitroblue tetrazolium dye reduction, chemiluminescence, phagocytosis, microbial killing, adhesion, locomotion, intravascular recovery and half life. These tests indicate that the sequential loss of various neutrophil functions during storage is in the reverse order of their chronological acquisition during cellular maturation. Chemotaxis is the most sensitive indicator of neutrophil damage. In vitro tests show that neutrophils can be stored for approximately 24 hours. However, in vivo tests of chemotaxis suggest that this may be too optimistic. Whole blood, plasma and synthetic media have been evaluated for storage. Investigations of the latter are embryonic and further efforts should be encouraged. Several storage conditions have been evaluated. These studies suggest that the ideal conditions for storage area a pH of 7.2, room temperature (20-24C) and no agitation. Neither premedication of the donor with glucocorticoids nor irradiation of the granulocyte concentrate alters the storage potential of the unit. Cells collected by filtration leukapheresis should not be stored.

Blood Donors↗
PubMed1981

Functional differentiation in acute monoblastic leukemia.

Blasts from the bone marrow of a patient who had acute monoblastic leukemia were studied for functional maturity. Classification of the leukemia was based on cytochemical stains. The blasts were negative when stained with Sudan black B and did not have specific esterase activity. They were rich in alpha-naphthyl butyrate esterase, which was inhibited by fluoride. Functional assays included phagocytosis of Candida albicans, fungicidal activity measured by differential Giemsa staining of the ingested C. albicans, and locomotion using the agarose method to evaluate both random migration and chemotaxis. At a ratio of 20 yeast cells to one monoblast, 80% of the blasts could be stimulated to phagocytize an average of 4.4 organisms. These results compared favorably with the phagocytic potential of normal human monocytes. Candidacidal activity was present, but reduced. At high ratios of yeasts to monoblasts, only ten organisms were killed for every 100 phagocytic blasts. This correlates with the absence of myeloperoxidase activity demonstrated by negative Sudan black B staining. Neither chemotaxis nor random migration could be demonstrated, indicating that monoblasts lacked the apparatus necessary for locomotion. Extrapolation of these findings to normal monocyte maturation suggests that phagocytosis is acquired prior to microbicidal activity, which develops prior to locomotion.

Adult↗