Effect of aluminum and pH on the growth of Anacystis nidulans.
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Aluminum↗
Biomedical subjects
L H Lee
Publications and source records attributed to L H Lee.
Timing and patterns of astrocyte migration from xenogeneic transplants of the cortex and corpus callosum.
The timing, pattern, and pathway of astrocyte migration were investigated in vivo by transplantation of CD-1 mouse cerebral cortex (E13-14) or corpus callosum (P2-3) into neonatal rat cortex. A monoclonal antibody specific for a mouse astrocyte surface antigen (M2) was used to identify the location of the grafts and the migrated donor astrocytes. Within the host cortex, astrocytes from cortical grafts began migration at post-transplantation day (PTD) 7. Over the next 4 days, the most distant displaced donor cells were found progressively further away from the grafts, migrating at a rate of about 220 microns/day. After PTD 11, the migration rate for the farthest displaced donor cells slowed to 25 microns/day, and the cells appeared to stop at about PTD 16 at a distance of 1,100 microns from the edge of the graft. Astrocytes had a faster migration speed in the white matter and covered a longer distance (5 mm) than those in the gray matter, extending on occasion into the contralateral hemisphere. The patterns of astrocyte migration differed depending on local cues around the transplant. Donor astrocytes that had been implanted into the host cortex migrated toward the host cortical surface, sometimes in several radial lines. Astrocytes from grafts, especially callosal grafts, placed in the subcortical white matter migrated along the host fiber tracts. Many astrocytes transplanted into the hippocampus formed laminar patterns close to the hippocampal neuronal layers. These results suggest that the direction, pattern, and speed of astrocyte migration are influenced by local substrates in the host brain.
Animals↗
Monoclonal antibodies against different epitopes of a 40 Kd capsid protein of infectious bursal disease viruses.
Nine monoclonal antibodies (Mab) against a 40 Kd capsid protein of infectious bursal disease virus (IBDV) strain P3009 were isolated. They were characterized by enzyme-linked immunosorbent assay, indirect fluorescent antibody staining and virus neutralization. They were divided into two groups concerning virus neutralization. Group I Mabs were able to neutralize virus infectivity; however, group II Mabs were not. Competitive binding assays using these Mabs demonstrated the existence of two distinct antigenic regions (A and B) on the 40 Kd protein. Region A was recognized by group I Mabs and region B was by group II Mabs. The binding reaction with group I Mabs was affected by denaturing of the viral proteins, indicating that the antigenic region involving neutralization was conformation-dependent. The results of enzyme-linked immunosorbent assays and virus neutralization tests suggested that group I Mabs might react with one epitope within region A and group II Mabs with 2 or 3 epitopes within region B.
Antibodies, Monoclonal↗
tri-n-Butyltin: a membrane toxicant.
Increased use of the biocidal compound tri-n-butyltin (TBT) in antifouling paints has prompted research aimed at determining the mechanism for TBT toxicity. Past investigations indicate that the primary cellular target for TBT is the cell membrane. Erythrocyte suspensions treated with TBT concentrations 2 greater than or equal to 5 microM undergo hemolysis described by a sigmoidal kinetic pattern. Transformation of cell shape from discocyte to echinocyte occurs at TBT concentrations greater than or equal to 0.1 microM, indicating that the compound enters the outer membrane bilayer. TBT at concentrations greater than or equal to 10 microM forms electron-dense aggregates that are intercalated within plasma membranes as viewed in ultrathin sections by transmission electron microscopy. Qualitative X-ray microanalysis of these aggregates confirms the presence of tin. The size of these structures can be modified by either 10 mM cyanide or 2,3-dimercaptopropanol (British Anti-Lewisite, BAL). Adding 10 mM cyanide to hemolytic TBT concentrations resulted in a synergistic stimulation of hemolysis attributable to high cyanide anion concentrations in or near the cell membrane. The elevated cyanide anion levels are thought to contribute to membrane lysis. The lipophilic dimercapto compounds BAL, dithiothreitol, and 2,3-dimercaptosuccinate are effective inhibitors of TBT-induced lysis. Water-soluble 2,3-dimercapto-1-propane sulfonate, a BAL analog, was largely ineffective as an inhibitor. The detailed molecular mechanism for TBT-induced membrane lysis is not yet clear. Cellular ATP depletion could be induced by TBT as well as by delipidation of anionic phospholipids or even formation of tributylstannylperoxy radicals, resulting in lipid peroxidation.
Chemical Phenomena↗
Organotin-induced hemolysis, shape transformation and intramembranous aggregates in human erythrocytes.
Organotin compounds examined in this study exhibited a relative order of potency for induction of in vitro hemolysis in human erythrocytes as follows: tri-n-butyltin greater than tri-n-propyltin greater than tetra-n-butyltin greater than triphenyltin chloride greater than tri-n-ethyltin bromide greater than dibutyltin dichloride greater than stannous chloride greater than tri-n-methyltin chloride = butyltin chloride dihydroxide. All of the organotin compounds induced erythrocyte shape transformation from the normal discocyte to an echinocyte and, in addition, triphenyltin chloride, tetra-n-butyltin and tri-n-ethyltin bromide also elicited stomatocyte formation at higher concentrations. Select organotin compounds also formed tin-containing aggregates within the plasma membrane. The relative order of effectiveness for organotin induction of intramembranous aggregates was tri-n-butyltin greater than tri-n-propyltin greater than tetra-n-butyltin greater than tri-n-ethyltin bromide, which was based upon the lowest concentration at which they were observed. These results support the previously suggested theory that organotins are membrane effectors because of their comparatively high hydrophobic, lipid partitioning properties. The relatively lipophilic compound, triphenyltin chloride, appeared to be anomalous because it did not readily promote hemolysis or induce the formation of intramembranous aggregates in human erythrocytes. A log-linear statistical model demonstrated an association of hemolysis with both tri-n-butyltin aggregate formation and shape transformation. Select organotin compounds should be useful probes in membrane studies because of their numerous effects.
Erythrocyte Aggregation↗
[Rehabilitation of heat stroke with cerebellar ataxia--a report of two cases].
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Adult↗
Cyanide stimulation of tri-N-butyltin mediated hemolysis.
The effects of tributyltin and sodium cyanide on hemolysis in human erythrocytes are described. Tributyltin has a sharp cut-off concentration for induction of hemolysis. A 5 microM concentration of tributyltin induces hemolysis and 1 microM or less does not in erythrocyte suspensions with 2.3 X 10(8) cells per ml. The kinetics for tributyltin-induced hemolysis are sigmoidal indicating a complex molecular mechanism leading to lysis. Ten mM sodium cyanide plus 1 microM tributyltin does not stimulate hemolysis rates above levels observed with 10 mM sodium cyanide alone. Five mM sodium cyanide plus hemolytic concentrations of tributyltin stimulates hemolysis rates synergistically compared with either cyanide or tributyltin alone. Ultrastructurally, hemolytic concentrations of tributyltin can be visualized in the electron microscope by osmium staining during fixation as electron-dense spheres penetrating the lipid bilayer of the erythrocyte plasma membrane. Ten mM sodium cyanide plus 25 microM tributyltin increases slightly the size of osmiophilic structures in erythrocyte membranes compared with those spheres seen in cells exposed to 25 microM tributyltin alone. Sodium cyanide is the only compound tested that stimulates tributyltin-induced hemolysis. Sodium thiocyanate, previously shown to be rapidly exchanged across erythrocyte membranes by tributyltin, reduces the rate of hemolysis. It is likely that sodium cyanide stimulates hemolysis in the presence of hemolytic tributyltin concentrations because the multimolecular, membrane-intercalated, tributyltin aggregates are transporting cyanide anion by the electrically silent, anion exchange mechanism demonstrated for other anions. It is suggested that this mechanism delivers cyanide anion to or near critical membrane sites where it is available for enzyme inhibition or cross-linking of protein sulfhydryl groups.
Cyanides↗
Inhibition of tributyltin mediated hemolysis by mercapto compounds.
Hydrophobic tributyltin (TBT) compounds at concentrations greater than 10 microM caused hemolysis of human erythrocytes and formed structures in plasma membranes. The mercapto compounds, beta-mercaptoethanol (beta MER), 2,3-dimercaptopropanol (BAL), 2,3-dimercapto-1-propane sulfonate (DMPS), DL-dithiothreitol (DTT), and meso-2,3-dimercaptosuccinic acid (DMSA) were examined for their ability to inhibit TBT mediated hemolysis. The relative order of effectiveness for inhibition of TBT mediated hemolysis was BAL greater than DTT greater than DMSA greater than DMPS greater than beta MER. A four-fold excess of BAL over TBT prevented hemolysis for 4 hrs and addition of BAL 0.5 hr after TBT reduced the rate of hemolysis. The number of membrane associated TBT aggregates observed per cell profile decreased as the BAL concentration increased from 0 to 100 microM. However, the mean diameter of TBT aggregates nearly doubled in erythrocyte suspensions at 100 microM BAL. Reactions of dimercapto compounds with lipophilic TBT aggregates may depend on their relative lipid solubilities. Also, conversion of the weak Lewis acid, TBT, from a four to a five or six-coordinate tin adduct by the dimercapto Lewis bases used could also be a factor slowing hemolysis rates.
Erythrocytes↗
Aspiration biopsy of the kidney. Simultaneous collection of cytologic and histologic specimens.
Aspiration biopsy of mass lesions of the kidney is a diagnostic procedure whose potential benefit to patients with equivocal radiologic findings, suspected metastases, palpable flank masses, nonfunctioning kidneys and even cortical cysts has not been fully explored. Over the past 7 years 163 renal aspiration specimens from 152 patients have been examined. Diagnostic yield was enhanced by use of modified "fine" needles with notched tips so that tissue fragments for histology as well as smears for cytology were obtained in 89% of solid tumors. The availability of aspirated tissue contributed significantly to pathologic classification and often spared patients additional surgery for confirmation of the cytologic diagnosis. Among the 152 cases, there were 35 with renal cell carcinomas, a sufficient number for detailed semiquantitative evaluation of their cytologic features. The remaining cases comprised metastatic carcinomas, lymphomas, transitional cell carcinomas, oncocytomas, cortical cysts, and miscellaneous conditions, e.g., abscesses, nonfunctioning kidneys, and hematomas. Overall, the aspiration biopsy determined the nature of the renal mass in 141 cases (93%). False-negative interpretations were due to insufficient diagnostic material in all but one instance. There was one false-positive result.
Adenoma↗
Interspecies variability in propylene glycol dinitrate-induced methemoglobin formation.
Interspecies variability of propylene glycol dinitrate (PGDN)-induced methemoglobin formation was studied in vitro employing erythrocytes from four separate species. The net rate of methemoglobin formation was significantly different among species with dog greater than guinea pig greater than rat greater than or equal to human. This order of susceptibility was maintained in stroma-free hemolysates, indicating that interspecies variability was not a reflection of differences in red cell membrane permeability or intracellular transport of PGDN. The erythrocytic enzymes, catalase, superoxide dismutase, glutathione peroxidase, 6-phosphogluconate dehydrogenase, glucose-6-phosphate dehydrogenase, methemoglobin reductase, and glutathione-S-transferase, were assayed by adaptation of existing methods to a centrifugal analyzer. The above enzymes were removed from hemoglobin derived from each species and the order of susceptibility to PGDN-induced methemoglobin formation remained essentially the same with dog greater than guinea pig greater than human = rat. However, the net rate of PGDN-mediated oxidation of hemoglobin to methemoglobin increased in purified hemoglobin preparations from each species. These results demonstrate that there is species variability in the net rate of PGDN-mediated methemoglobin formation. Total enzyme activity in erythrocytes may contribute to reduction in the net rate of methemoglobin formation. However, the primary determinant of the net rate of methemoglobin formation induced by PGDN appears to be the structure of each hemoglobin molecule.
Animals↗
The role of aspiration biopsy cytology in the diagnosis of pulmonary tuberculosis.
The experience at one institution concerning the diagnosis of pulmonary tuberculosis by aspiration biopsy is reviewed. Twelve cases in which acid-fast bacilli were identified in pulmonary aspiration material are reported. The cytologic findings were confirmed by microbiologic culture in nine cases. The advantages of using aspiration biopsy cytology in the diagnosis of pulmonary tuberculosis are discussed. In our experience we conclude that the use of aspiration biopsy cytology in the diagnosis of pulmonary tuberculosis is not only accurate, but also offers several advantages that are important in patient care.
Biopsy, Needle↗
Mediastinal needle biopsy.
A review of 52 consecutive needle biopsies of the mediastinum is presented. The aspirated material yielded cytologic and/or histologic diagnosis in 50 needle biopsies; two needle biopsies failed to yield adequate cellular material for diagnosis. All but two of the 50 patients had confirmation of the biopsy diagnosis by surgical, autopsy, or clinical correlation. In 32 patients, a 20-gauge needle was used for the biopsy. A larger-bore (17-gauge) needle with a cutting device was used in 20 cases to obtain more tissue for histologic diagnosis of benign or unusual malignant lesions. Despite the larger size of the needle, the rate of complications remained low.
Adolescent↗
Evidence for the synchronous replication of mitochondrial DNA during the yeast cell cycle.
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Adenine↗
Seroimmunity of National servicemen in Singapore to poliomyelitis.
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Adolescent↗
Enzymatic assembly of slow reacting substance.
When basophils or mast cells are stimulated by a specific antigen they release chemical mediators, including a potent bronchoconstrictor, slow reacting substance of anaphylaxis (SRS-A). The structure of SRS from a mouse mastocytoma and rat basophilic leukaemia (RBL-1) cells has been identified as a thioether or arachidonic acid and glutathione [not a thioether of cystene as was originally thought]. SRS has been named leukotriene (LT) C and may be formed by a novel lipoxygenase pathway which also synthesizes 5,6-oxido-7,9,11,14-icosatetraenoic acid (LTA) and 5,12-dihydroxy-6,8,10,14-icosatetraenoic acid (LTB). Homogenates of RBL-1 cells, when incubated with C-arachidonic acid, form 5-hydroxy-icosatetraenoic acid (5-HETE) and 5,12-dihydroxy- and 5,6-dihydroxy-icosatetraenoic acid. The latter is the spontaneous breakdown product of the labile intermediate LTA. Formation of both compounds is stimulated by calcium. We have now produced biologically active SRS in a cell-free system generated from RBL-1 cells. Glutathione was essential for SRS synthesis and calcium stimulated its formation.
Animals↗
Enzymatic formation of prostaglandin D2 by rat basophilic leukemia cells and normal rat mast cells.
It has been shown that the major cyclooxygenase product in rat basophilic leukemia (RBL-1) cells and in normal rat mast cells is prostaglandin D2. In RBL-1 cells, prostaglandin D2 is isomerase activity was found in the 150 000 X g microsomal pellet as well as the supernatant fraction. Incubation of RBL-1 microsomes with arachidonic acid without cofactors yielded 17.5 +/- 2% prostaglandin E2 and 9.1 +/- 1.4% prostaglandin D2. The cyclooxygenase activity was enhanced (25%) by epinephrine and the addition of reduced glutathione led to a marked increase in prostaglandin D2 synthesis (3-fold). Incubations with arachidonic acid, glutathione and epinephrine gave the maximum conversion to prostaglandin D2, yielding 7 +/- 0.4% prostaglandin E2 and 35.6 +/- 3.5% prostaglandin D2. Incubations with [14C]prostaglandin H2 to bypass cyclooxygenase confirmed the presence and glutathione dependence of the prostaglandin D2 isomerase in the microsomal fraction and also revealed the presence of the same enzyme in the 150 000 X g supernant. In contrast to RBL-1 cells, incubations of microsomes and supernatant from normal rat mast cells with [14C]-arachidonic acid and [14C]prostaglandin H2 localized the prostaglandin D2 isomerase activity in the soluble fraction. Similar to the enzyme in the RBL-1 cells, the mast cell enzyme was glutathione dependent.
Animals↗
Identification of prostaglandin D2-isomerase in rat basophilic leukemia and rat mast cells.
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Animals↗
Influence of temperature on ionic sparing effect and cell-associated cations in the moderate halophile, Micrococcus varians var. halophilus.
Cells of the moderately halophilic Micrococcus varians var. halophilus grew well in a chemically defined medium containing 1 to 3 M NaCl and 0.0103 M K+. The requirement for NaCl could be partially replaced by K+,:Li+ and Cs+. The efficiency of the sparing effect of these cations for NaCl was in order of K+ GReater than Li+ greater than Cs+. Increase in growth temperature was found to enchance the sparing effect of Li+ and Cs+ but not that of K+. Over the range of NaCl concentrations in which the cells grew well, cell-Na+ concentrations were similar to the medium NaCl concentrations while cellK+ concentrations were several-fold that in the medium. Cell-bound Na+ and K+ concentrations increased proportionally with medium NaCl concentration and growth temperature. The temperature-dependent cation accumulation was more obvious with K+ than Na+. The cell-associated Na+ + K+ concentrations were almost as high as or slightly higher than the external media which contained appropriate levels of NaCl regardless of the growth temperature.
Cesium↗