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M A Anderson

Publications and source records attributed to M A Anderson.

At least 19 recordsLinked to original sources
PubMed1992

Development and characterization of a rapidly proliferating, well-differentiated cell line derived from normal adult human osteoblast-like cells transfected with SV40 large T antigen.

A new bone cell line was established by transfecting normal adult human osteoblast-like (hOB) cells, derived from a 68-year-old woman, with the plasmid pSV3 neo. The plasmid included coding sequences and promotors for the large and small T antigens of the SV40 virus as well as resistance to the antibiotics neomycin and G418. A single antibiotic-resistant colony was located and cloned. Large tumor antigen production in the clonal cell line was confirmed by indirect immunofluorescence study. Treatment with 1,25-dihydroxy-vitamin D3 increased steady-state concentrations of protein and mRNA for osteocalcin and for alkaline phosphatase. Northern blot analyses also demonstrated the presence of mRNAs for alpha(I)-procollagen, osteopontin 1a, transforming growth factor beta, and interleukin-1 beta. The plasma membrane calcium pump and osteonectin were identified by immunocytochemical analysis. These cells produced a matrix that mineralized when beta-glycerophosphate was added to their cultures. As assessed by functional receptor assays, both estrogen and androgen receptors were present and functional, although at low concentrations. Treatment with parathyroid hormone did not stimulate adenylate cyclase activity. Thus, these cells are a well-differentiated, steroid-responsive clonal cell line that closely approximates the phenotype of the mature osteoblast. They should serve as an excellent model for the study of osteoblast biology.

Aged↗
PubMed1992

Molecular analysis of human chromosome 16 cosmid clones containing NotI sites.

To test the feasibility of using cloned NotI sites as markers for physical mapping, we have screened for cosmid clones spanning the NotI sites on human Chromosome (Chr) 16. Fluorescence in situ hybridization analysis of these clones confirms the previously reported cluster of NotI sites on 16p13.3. Methylation status of the cloned NotI sites on genomic DNA was established by hybridization of the cosmids to Southern blots containing EcoRI and EcoRI/NotI digest of genomic DNA. These results indicated that four of six clones included in our study can be used as linking clones for physical mapping. Two clones have NotI sites which are not cleavable in the cell lines tested. In one clone, the NotI site exists as an isolated rare-cutting restriction enzyme site, whereas in the other clone the NotI site appears to be island-related.

Blotting, Southern↗
PubMed1992

A radiation-reduced hybrid cell line containing 5 Mb/17 cM of human DNA from 9q34.

Disease gene loci for tuberous sclerosis (TSC1), idiopathic torsion dystonia (DYT1), and nail-patella syndrome (NPS1) have been mapped by genetic linkage analysis to human chromosome 9q band 34. To create a resource for physical mapping and manipulation of this region of the genome, we have created a radiation-reduced hybrid cell line containing DNA from human 9q34 as its only human component. This cell line, E6B, has been characterized by Southern blot and PCR analysis using a panel of 9q markers and fluorescent in situ hybridization. We estimate that it contains 5 Mb of human DNA, equal to 17 cM of genetic distance, extending from AK1 to ABO on 9q34.

Cell Line↗
PubMed1992

Pharmacological characterization of lower esophageal sphincter relaxation induced by swallowing, vagal efferent nerve stimulation, and esophageal distention.

To characterize the neural pathways involved in lower esophageal sphincter relaxation, intraluminal pressures from the lower esophageal sphincter of the opossum were monitored during swallowing, vagal efferent nerve stimulation, and intraluminal balloon distention in the presence and absence of pharmacologic antagonism of putative neurotransmitters. The combination of atropine, hexamethonium, and 5-methoxydimethyltryptamine, which is known to block ganglionic transmission in the vagal inhibitory pathway to the lower esophageal sphincter, significantly antagonized LES relaxation induced by both swallowing and vagal stimulation, but did not affect the LES relaxation induced by balloon distention. Administration of the nitric oxide synthase inhibitor N omega nitro-L-arginine methyl ester, on the other hand, markedly inhibited LES relaxation induced by vagal stimulation, swallowing, and balloon distention, and this effect was reversed by administration of the nitric oxide synthase substrate L-arginine. These studies indicate that the distension-induced intramural pathway mediating LES relaxation does not involve ganglionic transmission similar to that of the vagal inhibitory pathway to the LES. However, the LES relaxation induced by all forms of stimuli appears to depend on nitric oxide as a final mediator.

Animals↗
PubMed1991

Procalcitonin NH2-terminal cleavage peptide has no mitogenic effect on normal human osteoblast-like cells.

The NH2-terminal cleavage peptide of procalcitonin (N-proCT) recently was reported to be a bone cell mitogen (Burns DM et al., Proc Natl Acad Sci USA 86:9519-9523, 1989). We have investigated the effect of N-proCT on the proliferation of normal human cells that have the phenotype of mature osteoblasts (hOB cells). N-proCT treatment for 24, 48, or 96 h in concentrations from 1 nM to 1 microM did not significantly increase [3H]thymidine uptake (means ranged from -19% to 38% of control, no significant differences) in hOB cells (6-10 cell strains per experiment) plated at four different densities. However, the hOB cells responded significantly to treatment with transforming growth factor beta (3 ng/ml), bovine insulin (300 micrograms/ml), or 30% fetal calf serum, which were included in all experiments as positive controls. The [3H]thymidine uptake data were confirmed in a direct cell count experiment tested at 96 h. Thus our data do not support the hypothesis that N-proCT is a potent mitogen for normal human osteoblasts.

Calcitonin↗
PubMed1991

Modulation of transforming growth factor-beta production in normal human osteoblast-like cells by 17 beta-estradiol and parathyroid hormone.

Although our laboratory has reported that normal human osteoblast-like (hOB) cells contain estrogen receptors, we have failed to find major effects of 17 beta-estradiol (E2) on modulation of proliferation of bone matrix protein production by hOB cells. Because the major effect of E2 in vivo is to decrease bone resorption and because transforming growth factor-beta (TGF-beta) has been reported to decrease osteoclast-mediated bone resorption, we have tested the hypothesis that the effect of E2 on osteoclast activity is, at least in part, indirectly mediated by enhancing production of TGF-beta by osteoblasts. We therefore have extended our studies to examine possible TGF-beta gene expression including the modulation of the release of TGF-beta by E2 in near homogenous populations of hOB cells. TGF-beta protein production was measured using growth inhibition of CCL-64 cells and verified by blocking effects with anti-TGF-beta antibodies. TGF-beta 1 messenger RNA (mRNA) steady state levels were assessed by northern blot analysis and quantitated by densitometric measurement using 18S ribosomal RNA as a reference. There was an E2 dose-dependent increase in TGF-beta protein production within 24 h of challenge with E2. Northern blots from these cells demonstrated a dose-dependent increase in steady state mRNA levels of TGF-beta 1 within 6 h of treatment. PTH was also a potent stimulator of TGF-beta protein and message levels in a dose-dependent manner. Interestingly, coincubation of equimolar concentrations of E2 and PTH (10(-8) M) abrogated the stimulation of TGF-beta 1 mRNA and protein. Decreasing the relative concentration of PTH in this coincubation with E2 increased TGF-beta 1 mRNA and protein levels. These data support the fact that E2 modulates TGF-beta production in osteoblasts. In this manner TGF-beta may mediate E2 inhibition of osteoclast activity.

Blotting, Northern↗
PubMed1991

Use of grounded theory methodology in a descriptive research design.

The purpose of this descriptive study is to illustrate how grounded theory methodology can be used for a descriptive survey study and also explains the implementation of the stepwise procedure. The focus of this study was on self-reported decisions made by new graduates from three different types of nursing programs (baccalaureate, associate degree and diploma) while assessing, planning, implementing and evaluating nursing care on medical-surgical units. The subjects' responses were analyzed using six steps of grounded theory methodology to classify the type and complexity of decisions (Glaser & Strauss, 1967). Harrison's model of decision making was used as a theoretical framework because it provides a typology for decision making that may be applied to various levels within the hospital setting.

Clinical Competence↗
PubMed1991

Molecular and evolutionary aspects of self-incompatibility in flowering plants.

Self-incompatibility (SI) is widely distributed in flowering plants. In this review, early work on the biology, genetics and distribution of SI is summarized. Approaches to understanding the molecular genetics of SI have been made in two systems-Solanaceous species, for example Nicotiana alata, which have gametophytic systems of SI, and Brassica spp, which have sporophytic systems of SI. The information in both systems is derived from cDNAs that encode pistil glycoproteins (S-glycoproteins) that segregate with S-genotype. Comparison of the sequence data indicates that the gametophytic and sporophytic systems of SI probably arose independently during the evolution of angiosperms. The S-glycoproteins of a solanaceous plant Nicotiana alata, are ribonucleases (RNases). Whether the RNase activity is directly involved in the characteristic arrest of pollen tube growth during self-(incompatible) pollination, is not known. An alternative possibility is that the RNase was 'recruited' during evolution for a function in SI, without involvement of its catalytic function. The nature of the S-gene in pollen is not yet known for either the gametophytic or sporophytic SI systems. This is a key piece of information that will be required to progress our understanding of how the growth of a pollen tube bearing a particular S-allele is arrested within the style bearing an identical S-allele, but is not arrested within the style bearing other S-alleles.

Amino Acid Sequence↗
PubMed1990

Self-incompatibility: a self-recognition system in plants.

Self-incompatibility (SI), a genetically controlled mechanism to prevent inbreeding in plants, offers a relatively simple model system for studying the interactions between plant cells or between a plant cell and the secreted product or products of another cell. Examples of two major types of SI, gametophytic and sporophytic, have been studied by cloning cDNAs corresponding to glycoproteins of the female tissues that segregate with particular variants encoded by the putative S locus. These secreted glycoproteins are envisaged to interact with the currently undescribed pollen component to cause arrest of pollen tube growth.

Amino Acid Sequence↗
PubMed1990

Amiloride inhibits contraction and serotonin modulation of Aplysia muscle.

1. Serotonin (5-HT) potentiates acetylcholine (ACh)-elicited contractions of Aplysia buccal muscles. Serotonin potentiation was significantly reduced by 0.03 mM, 0.1 mM, and 0.3 mM amiloride. 2. Unpotentiated ACh-elicited contractions were significantly reduced by 0.1 mM and 0.3 mM amiloride. 3. Amiloride reduced ACh-elicited depolarization. The reduction in contraction caused by 0.3 mM amiloride (to 16% of control) was larger than could be explained by the reduction in depolarization (86% of control). 4. Amiloride had no effect on tension in skinned muscle fibers, indicating that amiloride probably did not have a direct effect on contractile mechanisms. 5. Potentiation of contraction produced by zero sodium (Tris substituted, 0 Na-Tris) medium could be abolished by 0.3 mM amiloride. 6. Zero Na-Tris increased 45Ca influx 2.7-fold. In the presence of 0.3 mM amiloride, 0 Na-Tris increased 45Ca influx only 1.4-fold. 7. Amiloride (0.3 mM) reduced the elevation of muscle cAMP caused by 10(-6) M 5-HT by 60%. Zero Na-Tris did not cause a change in muscle cAMP.

Acetylcholine↗
PubMed1990

Agreement between arm circumference, weight for age, and weight for height measures of malnutrition in children.

Agewise agreement between mid-upper arm circumference (AC), weight for age and weight for height assessment of nutritional status was analyzed for 5,509 Indian children 1 to 5 years of age. Sensitivity specificity and positive predictive value of AC are presented. The sensitivity of AC for detecting moderate malnutrition by weight for age or weight for height was found to be low, except in children 13-24 months of age. From 25-58% of the severely malnourished children by weight for age in the age group 25-60 months were misclassified as normal by AC. Specificity of AC was high across the age range indicating that most of the children identified as not malnourished by weight for age or weight for height also had normal AC. The positive predictive value of AC was low for severe malnutrition but high for moderate to mild malnutrition compared to weight for age and weight for height. The findings indicate that AC is not constant over the age range 1 to 5 years, and use of fixed cut-off points for assessing malnutrition from 1 to 5 years is inappropriate. Sensitivity of AC using a fixed-cut-off point clearly decreases with age, and specificity increases with age. Where possible, weight of children is preferable to AC for nutritional status assessment, due to large number of moderately or severely malnourished children likely to be wrongly classified as normal by AC.

Age Factors↗
PubMed1989

Speciation of aluminum in aqueous solutions using ion chromatography.

An ion chromatographic method in which aluminum (AI) is quantitatively determined via postcolumn derivatization with Tiron (4,5-dihydroxy-m-benzenedisulfonic acid) was evaluated for its utility as a method for speciating AI in aqueous solutions. Fluro-, oxalato-, and citratoaluminum complexes were identified by distinct peaks within chromatograms of AI solutions when the appropriate ligand was added. Excellent quantitative agreement between predicted species concentrations (via the thermodynamic speciation model GEOCHEM) and those determined by ion chromatography was obtained for samples prepared in the eluent matrix. The predominantly outer sphere sulfatoaluminum complexes were not observed to elute as singly charged species, but rather exhibited a retention time indistinguishable from the AI(H2O)6(3+) species. It is concluded that inner sphere AI complexes (generally possessing relatively high association constants) possess adequate kinetic stability to withstand degradation during the ion exchange process, whereas outer sphere complexes apparently readily dissociate in the presence of the sulfonate exchange sites. Deviations in sample ionic strength (mu) and pH from that of the eluent resulted in some redistribution among species, the degree of which was ligand specific.

Aluminum↗
PubMed1989

Recent developments in the molecular genetics and biology of self-incompatibility.

A summary of recent work on molecular aspects of self-incompatibility in Nicotiana alata is presented. The amino acid sequences of style proteins corresponding to different S-alleles of N. alata have a high level of homology in some regions and are variable in other regions. The regions of homology include N-terminal sequences as well as most of the glycosylation sites and cysteine residues. The glycosyl substituents may consist of a number of 'glycoforms'. The isolated style S-glycoproteins inhibit in vitro growth of pollen tubes. The S-glycoproteins tested inhibited the growth of pollen of several S-genotypes, and there was some specificity in the interaction. Heat treatment of the isolated S-glycoproteins dramatically increased their activity as inhibitors of pollen tube growth, although the specificity in the interaction was lost. The nature of the S-allele products in pollen is not yet established.

Alleles↗
PubMed1989

Multiple intra-cranial hemorrhages after carotid endarterectomy.

Intra-cerebral hemorrhage is an unusual and often fatal complication of endarterectomy (CEA). Previous cerebral infarction, intra-operative or post operative hypertension, and the use of anti-coagulants are some of the defined major risk factors. Hemorrhage usually occurs early after CEA, and a second hemorrhage has only once been reported. We wish to report a patient who developed three separate hemorrhages following CEA. This patient had a long history of poorly controlled hypertension. We believe that poorly controlled hypertension, in addition to other reported factors, may be an important separate risk factor for post-CEA hemorrhage.

Carotid Artery Diseases↗
PubMed1989

Sequence variability of three alleles of the self-incompatibility gene of Nicotiana alata.

Three alleles of the self-incompatibility gene of Nicotiana alata have been cloned and sequenced. A comparison of the sequences shows a surprisingly low level of homology (56%) and the presence of defined regions of homology and variability. The homologous regions include the N-terminal sequence, most of the cysteine residues and glycosylation sites, as well as other blocks throughout the sequence. We interpret these conserved regions as "framework" and nonconserved regions as "hypervariable," following the terminology used to describe analogous regions in the IgG supergene family. The low level of overall homology forms the basis of a general method for isolating S-allele-specific cDNAs. Allele-specific antibodies can be generated using synthetic peptides corresponding to one of the variable regions. When applied to sections of the pistil, these antibodies label the intercellular matrix in the stigma and transmitting tissue of the style and the cell walls in the epidermis of the placenta. HindIII digestion of genomic DNA generates a characteristic pattern of S-gene fragments for each genotype. These restriction fragment length polymorphisms can be used to assign S-genotype to progeny arising from breeding experiments.

Alleles↗