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Biomedical subjects

R G Anderson

Publications and source records attributed to R G Anderson.

At least 181 records · Page 10Linked to original sources
PubMed1977

Clergy consultation as a community mental health program.

The authors describe the planning, development, implementation, and results of a consultation program to the clergy as part of an agency's community mental health service. The paper focuses on the four main program goals of (1) revitalizing a local association for the clergy, (2) developing the clergy's pastoral skills, (3) increasing community supports for mental health, and (4) developing a counseling service sponsored by the local clergy for community residents.

Clergy↗
PubMed1977

Role of the coated endocytic vesicle in the uptake of receptor-bound low density lipoprotein in human fibroblasts.

125I-labeled and ferritin-labeled low density lipoprotein (LDL) were used as visual probes to study the surface distribution of LDL receptors and to examine the mechanism of the endocytosis of this lipoprotein in cultured human fibrobasts. Light microscopic autoradiograms of whole cells incubated with 125I-LDL at 4 degrees C showed that LDL receptors were widely but unevenly distributed over the cell surface. With the electron microscope, we determined that 60-70% of the ferritin-labeled LDL that bound to cells at 4 degrees C was localized over short coated segments of the plasma membrane that accounted for no more than 2% of the total surface area. To study the internalization process, cells were first allowed to bind ferritin-labeled LDL at 4 degrees C and were then warmed to 37 degrees C. Within 10 min, nearly all the surface-bound LDL-ferritin was incorporated into coated endocytic vesicles that were formed by the invagination and pinching-off of the coated membrane regions that contained the receptor-bound LDL. With increasing time at 37 degrees C, these coated vesicles were observed sequentially to migrate through the cytoplasm (1 min), to lose their cytoplasmic coat (2 min), and to fuse with either primary or secondary lysosomes (6 min). The current data indicate that the coated regions of plasma membrane are specialized structures of rapid turnover that function to carry receptor-bound LDL, and perhaps other receptor-bound molecules, into the cell.

Cell Membrane↗
PubMed1977

Distribution of anionic sites on the oviduct ciliary membrane.

Polycationic ferritin (PCF) was used as a visual probe for anionic sites on the oviduct ciliary membrane. The binding of PCF to ciliary membranes was dependent on the concentration of the probe in the incubation media. At low concentrations (0.08-0.16 mg/ml), PCF was bound exclusively to the tip of the cilium whereas at higher concentrations (0.32-0.64 mg/ml), ferritin was located at the tip and at the base around the transition region, with occasional scattered clumps on the remainder of the membrane. The base and tip binding was fount to be associated with special surface modifications of the membrane in these regions. At the tip, PCF was bound to a filamentous glycocalyx termed the ciliary crown. Base binding was associated with a system of five to six 140-A high ridges, each of which encircled the membrane of the transition region. The ridges were equally spaced (approxamately 245 A spacing) along the length of the transition region. Since pretreatment of oviduct with either neuraminidase or protease blocked the binding of the probe, the PCF-binding sites appear to be negatively charged glycoproteins or mucopolysaccharides.

Animals↗
PubMed1977

Metabolism of cationized lipoproteins by human fibroblasts. Biochemical and morphologic correlations.

Human plasma low density lipoprotein (LDL) that had been rendered polycationic by coupling with N, N-dimethyl-1, 3-propanediamine (DMPA) was shown by electron microscopy to bind in clusters to the surface of human fibroblasts. The clusters resembled those formed by polycationic ferritin (DMPA-feritin), a visual probe that binds to anionic site on the plasma membrane. Biochemical studies with (125)I-labeled DMPA-LDL showed that the membrane-bound lipoprotein was internalized and hydrolyzed in lysosomes. The turnover time for cell bound (125)I-DMPA-LDL, i.e., the time in which the amount of (125)I-DMPA-LDL degraded was equal to the steady-state cellular content of the lipoprotein, was about 50 h. Because the DMPA-LDL gained access to fibroblasts by binding nonspecifically to anionic sites on the cell surface rather than by binding to the physiologic LDL receptor, its uptake failed to be regulated under conditions in which the uptake of native LDL was reduced by feedback suppression of the LDL receptor. As a result, unlike the case with native LDL, the DMPA-LDL accumulated progressively within the cell, and this led to a massive increase in the cellular content of both free and esterified cholesterol. Studies with (14)C-oleate showed that at least 20 percent of the accumulated cholesteryl esters represented cholesterol that had been esterified within the cell. After 4 days of incubation with 10 mug/ml of DMPA-LDL, fibroblasts had accumulated so much cholesteryl ester that neutral lipid droplets were visible at the light microscope level with Oil Red O staining. By electron microscopy, these intracellular lipid droplets were observed to lack a tripartite limiting membrane. The ability to cause the overaccumulation of cholesteryl esters within cells by using DMPA-LDL provides a model system for study of the pathologic consequences at the cellular level of massive deposition of cholesteryl ester.

Binding Sites↗
PubMed1977

Biochemical and cytochemical evidence for ATPase activity in basal bodies isolated from oviduct.

Biochemical and cytochemical techniques were used to determine whether oviduct basal bodies have ATPase activity. All studies were carried out on basal bodies isolated and purified from the chicken oviduct. These preparations contained structurally intact basal bodies with basal feet, rootlet, and alar sheet accessory structures. Whereas the specific activity of the basal body ATPase in 2 mM Ca++ or 2 mM Mg++, 1 mM ATP, pH 8.0, averaged 0.04 mumol Pi/min per mg protein, higher concentrations of either cation inhibited the enzyme activity. Furthermore, the pH optimum for this reaction was pH 8.5. In comparison, the ATPase activity in cilia purified and measured under conditions identical to those for determining the basal body ATPase activity averaged 0.07 mumol Pi/min per mg protein. However, the activity increased at higher concentrations of divalent cation, and the pH optimum was pH 10.0. By cytochemical procedures for localizing ATPase activity, ATP-dependent reaction product in isolated basal bodies was found to be confined to: (a) the cross-striations of the rootlet; (b) the outer portion of the basal foot; (c) the alar sheets; and (d) the triplet microtubules. It is concluded that basal bodiesve an intrinsic ATPase activity that, by a variety of criteria, can be distinguished from the ATPase activity found in cilia.

Adenosine Triphosphatases↗
PubMed1977

Overloading human aortic smooth muscle cells with low density lipoprotein-cholesteryl esters reproduces features of atherosclerosis in vitro.

Human aortic smooth muscle cells accumulate only small amounts of cholesteryl esters in tissue culture, even when incubated for prolonged periods with high levels of plasma low density lipoprotein (LDL). This failure to overaccumulate LDL-cholesteryl esters is due to an LDL-mediated feedback suppression of the activity of the cell surface LDL receptor, a regulatory action that limits the rate at which the cells take up LDL. This regulatory system can be bypassed by incubating smooth muscle cells with LDL that has been given a strong positive charge by covalent linkage with N,N-dimethyl-1,3-propanediamine (DMPA-LDL). The unregulated uptake of DMPA-LDL produces a massive deposition of cholesteryl esters in the form of inclusions within the cell. These inclusions take up lipid stains and exhibit positive birefringence with formée crosses that are typical of liquid crystals of cholesteryl esters. By electron microscopy, the cholesteryl ester inclusions appear as homogeneous gray cytoplasmic lipid droplets. The current studies demonstrate that the unregulated uptake of LDL-cholesteryl esters by human aortic smooth muscle cells can reproduce in vitro the major biochemical and morphological alterations that occur within smooth muscle cells in vivo during the process of atherosclerosis.

Aorta, Thoracic↗
PubMed1976

Estrogen dependent ciliogenesis in the chick oviduct.

Both the hormone dependency and the morphological details of estrogen-dependent ciliogenesis in the shell gland of the chick oviduct were investigated. Ciliogenesis was initiated on day 3 of estrogen treatment, and progressively more cells became differentiated until, on day 10, approximately 55% ciliation occurred with 17 beta-estradiol (1 mg/day) and approximately 75% ciliation occurred with diethylstilbestrol (1 mg/day). Simultaneous administration of progesterone with diethylstilbestrol (1 mg each/day for 10 days) caused a 50% depression in the number of ciliated cells on day 10. The rate of ciliogenesis was found to be affected by progesterone and the type of estrogen administered. The minimum stimulatory dose of estradiol was found to be between 0.01 mg/day and 0.05 mg/day. Ciliogenic cells were first recognized by the appearance of pro-basal bodies in the apical portion of the cell. Pro-basal body maturation and cilium formation were the same as those described for the chick trachea. Ciliogenesis in the chick was found to be homologous to estrogen-dependent ciliogenesis in various mammalian oviducts.

Animals↗
PubMed1976

Localization of low density lipoprotein receptors on plasma membrane of normal human fibroblasts and their absence in cells from a familial hypercholesterolemia homozygote.

Monolayers of normal human fibroblasts were observed to bind ferritin-labeled low density lipoprotein (LDL-ferritin) at specific receptor sites on the cell surface membrane. When fibroblasts were incubated with LDL-ferritin at 4 degrees, more than 70% of the surface-bound ferritin cores were localized by electron microscopy to short segments of the plasma membrane where the membrane appeared indented and coated on both of its sides by a fuzzy material. These membrane segments corresponded to "coated regions" previously described in other cell types. Unver the conditions of these experiments, an average of 55 LDL-ferritin particles were bound to each millimeter of plasma membrane in normal cells. In the presence of a 15-fold excess of native LDL, the number of bound ferritin cores was reduced by 75%, suggesting that the LDL-ferritin was binding to specific LDL receptor sites. Although fibroblasts from a patient with the homozygous form of familial hypercholesterolemia contained the same number of indented, coated membrane regions per millimeter of cell surface as did normal cells, no LDL-ferritin was observed to bind to the cell membrane in these mutant cells. The present ultrastructural data are consistent with previous biochemical and genetic evidence indicating that LDL exerts its regulatory action on cellular cholesterol metabolism in fibroblasts through an interaction with a specific cell surface receptor and that this receptor is defective in homozygous familial hypercholesterolemia fibroblasts. Moreover, the data suggest that the LDL receptor is localized to indented, coated regions of the plasma membrane that appear to participate in the adsorptive endocytosis of proteins.

Cell Membrane↗
PubMed1975

Personal air sampling for vapors of aniline compounds.

A method has been developed for air sampling and laboratory analysis of vapors of seven aniline compounds: aniline, N,N-dimethylaniline, o-toluidine, 2,4-xylidine, panisidine, o-anisidine, and p-nitroaniline. Air is drawn by a personal sampling pump from a worker's breathing zone through a tube containing silica gel to collect any anilines present. In the laboratory each silica gel section is transferred to a glass-stoppered tube and desorbed with ethanol. An aliquot of this is analyzed by gas chromatography to determine the amount of each aniline compound present. The sampling tube can be used for short-term sampling at 1000 cm3/min or for sampling up to eight hours at 200 cm3/min. Maximum interference effects of water vapor have been considered. Results of retention, desorption, storage, accuracy, and precision studies are presented.

Absorption↗
PubMed1974

Isolation of ciliated or unciliated basal bodies from the rabbit oviduct.

Techniques have been developed for the isolation of basal bodies with cilia attached or for the isolation of only basal bodies from the rabbit oviduct. Oviducts are removed, cut open, and placed in an extraction medium composed of 0.25 M sucrose, 0.001 M EDTA, 0.025 M KCl, 0.02 M Hepes buffer pH 7.5, and 0.05% Triton X-100. After the oviduct is agitated in this medium on a Vortex mixer for (1/2) h, the lumenal cortex of each ciliated cell, containing 200-300 basal bodies with cilia attached, is released as a unit. The cortices and the intact nuclei, which are also released from the disrupted cells, form a pellet when the extraction medium is centrifuged at 600 g for 10 min. When cortices which contain only basal bodies are to be isolated, the oviduct is subjected to conditions which remove the cilia prior to being processed as above. The cilia are removed when the oviduct is placed in a medium of 0.25 M sucrose, 0.01 M CaCl(2), 0.02 M Pipes buffer pH 5.5, and 0.05% Triton X-100 and continuously agitated for 15 min on a Vortex mixer. The low pH and Ca(++) solubilize the transition region of the cilium and also prevent the cell from being disrupted. The cortices can be partially purified if the 600-g pellet is resuspended in 2.2 M sucrose pH 6.5 and centrifuged at 40,000 g for 2 h. Under these conditions, 85% of the nuclei form a pellet and the cortices float to the surface of the sucrose. In addition to the basal bodies or basal bodies with cilia, the cortices contain some adherent cytoplasm, a few fibers, and a few vesicles which may be remnants of mitochondria or endoplasmic reticulum. The structure of the cilia and the basal bodies isolated with either procedure is normal.

Animals↗
PubMed1973

The control of synthesis of bacterial cell walls. Interaction in the synthesis of nucleotide precursors.

Phosphoenolpyruvate-UDP-N-acetylglucosamine enolpyruvyltransferase, UDP-N-acetylglucosamine pyrophosphorylase and CDP-glycerol pyrophosphorylase activities were demonstrated in soluble extracts from Bacillus licheniformis A.T.C.C. 9945. The effect of various nucleotides, sugar nucleotides and sugar phosphates on the nucleotide pyrophosphorylases was investigated. UDP-N-acetylglucosamine pyrophosphorylase was inhibited by UDP-MurAc-pentapeptide (UDP-N-acetylmuramyl-l-alanyl-d-glutamyl- meso-diaminopimelyl-d-alanyl -d-alanine) and CDP-glycerol. CDP-glycerol pyrophosphorylase was inhibited by UDP-MurAc-pentapeptide and stimulated by UDP-N-acetylglucosamine. Interaction between a precursor of one cell-wall polymer and an enzyme involved in the synthesis of a precursor of a second polymer has therefore been demonstrated. The possible role of such interaction in the control of bacterial cell-wall synthesis is discussed. Of the other compounds investigated mono- and di-nucleotides were shown to be inhibitory, indicating that nucleotide pyrophosphorylase activities may be influenced by the energy charge of the cell.

Bacillus↗
PubMed1972

The mechanism of wall synthesis in bacteria. The organization of enzymes and isoprenoid phosphates in the membrane.

1. The synthesis of peptidoglycan and teichoic acids by cell-free preparations from Bacillus licheniformis A.T.C.C. 9945 and Bacillus subtilis N.C.T.C. 3610 has been studied under a variety of conditions. 2. It was shown that poly(glycerol phosphate) is synthesized through a lipid intermediate, and it is concluded from this and other work that all major bacterial wall polymers are formed in a similar manner through such intermediates. 3. Close interrelation between the synthesis of peptidoglycan and teichoic acids was demonstrated, and inhibition studies confirm that the polyprenol phosphate molecules participating in the synthesis of peptidoglycan are shared with the systems that synthesize teichoic acids. 4. Nucleotides for the synthesis of one polymer are inhibitory towards synthesis of the other, and these effects can be enhanced or diminished by preincubation of the enzyme system with appropriate nucleotide precursors. 5. It is concluded that the return of undecaprenol phosphate to a common pool occurs only after the completion of polymer chains, and not after each cycle in the attachment of individual repeating units. This and other observations support a model for bacterial wall synthesis in which the multi-enzyme systems for each polymer are closely aligned in the membrane, with a molecule of undecaprenol phosphate located between them in a manner that enables it to be shared. The general mechanisms of wall synthesis and its control are discussed.

Bacillus↗
PubMed1972

The three-dimensional structure of the basal body from the rhesus monkey oviduct.

The structure of the oviduct basal body has been reconstructed from serial, oblique, and tangential sections This composite information has been used to construct a three-dimensional scale model of the organelle The walls are composed of nine equally spaced sets of three tubules, which run from base to apex pitched to the left at a 10 degrees -15 degrees angle to the longitudinal axis. The transverse axis of each triplet set at its basal end intersects a tangent to the lumenal circumference of the basal body at a 40 degrees angle (triplet angle). As the triplet set transverses from base to apex, it twists toward the lumen on the longitudinal axis of the inner A tubule; therefore, the triplet angle is 10 degrees at the basal body-cilium junction. Strands of fibrous material extend from the basal end of each triplet to form a striated rootlet. A pyramidal basal foot projects at right angles from the midregion of the basal body. In the apex, a 175 mmicro long trapezoidal sheet is attached to each triplet set. The smaller of the two parallel sides is attached to all three tubules while the longitudinal edge (one of the equidistant anti-parallel sides) is attached to the C tubule. The sheet faces counterclockwise (apex to base view) and gradually unfolds from base to apex; the outside corner merges with the cell membrane.

Animals↗