Biomedical subjects

N L Anderson

Publications and source records attributed to N L Anderson.

At least 19 recordsLinked to original sources

PubMed2004

Altered localization of Cav1.2 (L-type) calcium channels in nerve fibers, Schwann cells, odontoblasts, and fibroblasts of tooth pulp after tooth injury.

We have determined the localization of Cav1.2 (L-Type) Ca2+ channels in the cells and nerve fibers in molars of normal or injured rats. We observed high levels of immunostaining of L-type Ca2+ channels in odontoblast cell bodies and their processes, in fibroblast cell bodies and in Schwann cells. Many Cav1.2-containing unmyelinated and myelinated axons were also present in root nerves and proximal branches in coronal pulp, but were usually missing from nerve fibers in dentin. Labeling in the larger fibers was present along the axonal membrane, localized in axonal vesicles, and in nodal regions. After focal tooth injury, there is a marked loss of Cav1.2 channels in injured teeth. Immunostaining of Cav1.2 channels was lost selectively in nerve fibers and local cells of the tooth pulp within 10 min of the lesion, without loss of other Cav channel or pulpal labels. By 60 min, Cav1.2 channels in odontoblasts were detected again but at levels below controls, whereas fibroblasts were labeled well above control levels, similar to upregulation of Cav1.2 channels in astrocytes after injury. By 3 days after the injury, Cav1.2 channels were again detected in nerve fibers and immunostaining of fibroblasts and odontoblasts had returned to control levels. These findings provide new insight into the localization of Cav1.2 channels in dental pulp and sensory fibers, and demonstrate unexpected plasticity of channel distribution in response to nerve injury.

Animals↗

PubMed2001

Cholesterol biosynthesis regulation and protein changes in rat liver following treatment with fluvastatin.

The enzyme 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase is a key regulator in cholesterol biosynthesis and HMG CoA reductase inhibitors (statins) have become a widely prescribed family of lipid lowering agents. Cholesterol synthesis occurs predominantly in liver which is the target organ of statins. We studied the effects of fluvastatin (Lescol), a member of the statin family, on hepatic protein regulation. Male F344 rats treated with 0.8 mg/kg per day fluvastatin or 24 mg/kg per day fluvastatin for 7 days showed treatment-related changes in 58 liver proteins (P<0.005). Major effects were evident in the cholesterol biosynthesis pathway including the induction of enzymes upstream and downstream of the target enzyme HMG CoA reductase. Treatment also triggered alterations in key enzymes of carbohydrate metabolism and was associated with changes in a heterogeneous set of cellular stress proteins involved in cytoskeletal structure, calcium homeostasis and protease activity. The latter set of protein alterations indicates that hepatotoxicity is associated with high-dose treatment. Based on the results it is suggested that HMG-CoA synthase and isopentenyl-diphosphate delta-isomerase may be explored as alternative drug targets and that the induction levels of these enzymes may serve as a measure of potency of individual statin drugs. It is proposed that efficacy and cellular stress markers discovered in this study may be used in a high throughput screen (HTS) assay format to compare efficiently and accurately the therapeutic windows of different members of the statin family.

Animals↗

PubMed2001

Back to the future: the human protein index (HPI) and the agenda for post-proteomic biology.

The effort to produce an index of all human proteins (the human protein index, or HPI) began twenty years ago, before the initiation of the human genome program. Because DNA sequencing technology is inherently simpler and more scalable than protein analytical technology, and because the finiteness of genomes invited a spirit of rapid conquest, the notion of genome sequencing has displaced that of protein databases in the minds of most molecular biologists for the last decade. However, now that the human genome sequence is nearing completion, a major realignment is under way that brings proteins back to the center of biological thinking. Using an influx of new and improved protein technologies--from mass spectrometry to re-engineered two-dimensional (2-D) gel systems, the original objectives of the HPI have been expanded and the time frame for its execution radically shortened. Several additional large scale technology efforts flowing from the HPI are also described.

Biotechnology↗

PubMed2001

Perceptions about risk for HIV/AIDS among adolescents in juvenile detention.

Although progress has been made toward reducing risk-taking behavior among teens, adolescents confined in juvenile detention facilities and youths living in inner cities remain vulnerable. Reaching these populations with appropriate risk-reduction strategies continues to challenge health providers and educators. Crucial first steps in the design of relevant programs involve discovering how at-risk teens perceive risk and which risks and dangers within their communities occupy their attention. Participants in this study did not identify HIV/AIDS as a primary concern; instead, they described the dangers and risks they encountered in their home neighborhoods. Based on these findings, this discussion addresses the implications for the development of health education programs to empower teens for responsible behavior after release from detention.

Adolescent↗

PubMed2000

Expression profiling in toxicology--potentials and limitations.

Recent progress in genomics and proteomics technologies has created a unique opportunity to significantly impact the pharmaceutical drug development processes. The perception that cells and whole organisms express specific inducible responses to stimuli such as drug treatment implies that unique expression patterns, molecular fingerprints, indicative of a drug's efficacy and potential toxicity are accessible. The integration into state-of-the-art toxicology of assays allowing one to profile treatment-related changes in gene expression patterns promises new insights into mechanisms of drug action and toxicity. The benefits will be improved lead selection, and optimized monitoring of drug efficacy and safety in pre-clinical and clinical studies based on biologically relevant tissue and surrogate markers.

Animals↗

PubMed2000

Two-dimensional electrophoresis of liver proteins: characterization of a drug-induced hepatomegaly in rats.

Two-dimensional electrophoresis (2-DE) of liver proteins was applied to further characterize an unusual drug-induced increase in hepatocellular rough endoplasmic reticulum (RER) in Sprague-Dawley rats given a substituted pyrimidine derivative. Absolute liver weights of drug-treated rats (9.9 +/- 0.4 g) increased above vehicle-treated controls (7.2 +/- 0.2 g) by 37%. Light microscopy revealed diffuse granular basophilia of the hepatocellular cytoplasm, uncharacteristic of hepatocytes and suggested cells rich in ribosomes, which was confirmed by electron microscopy. Immunostaining for cell proliferation, viz., 5-bromo-2'-deoxyuridine (BrdU) and proliferating cell nuclear antigen (PCNA), indicated marked hepatocellular proliferative activity. 2-DE of solubilized liver using an ISO-DALT gel system indicated significant (p<0.001) quantitative changes in at least 17 liver proteins (12 increased, 5 decreased) compared to controls. The protein with the largest increase was homologous to acute-phase reactant, contrapsin-like protein inhibitor-6. Other markedly upregulated proteins were methionine adenosyltransferase, a catalyst in methionine/ATP metabolism and mitochondrial HMG-CoA synthase, involved in cholesterol synthesis. The complementary strategies of 2-DE coupled either with database spot mapping or protein isolation and amino acid sequencing successfully identified a subset of proteins from xenobiotic-damaged rodent livers, the expression of which differed from controls. However, the current bioinformatics platform for rodent hepatic proteins and limited knowledge of specific protein functionality restricted application of this proteomics profile to further define a mechanistic basis for this unusual hepatotoxicity.

Animals↗

PubMed2000

Proteomics to display lovastatin-induced protein and pathway regulation in rat liver.

Lovastatin is a lipid lowering agent that acts by inhibiting 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, a key regulatory enzyme in cholesterol biosynthesis. In this study the pattern of gene network regulation induced in hepatic proteins as a response to lovastatin treatment was analyzed by proteomics. In livers of male F344 rats treated with 1.6 mg/kg/day lovastatin or 150 mg/kg/day lovastatin for seven days, 36 proteins were found to be significantly altered (p<0.001) in relation to treatment. The changed proteins were classified according to their cellular function and participation in biochemical pathways. The following observations were made: (i) inhibition of HMG-CoA reductase provoked a regulatory response in the cholesterol synthesis pathway including the induction of cytosolic HMG-CoA synthase and of isopentenyl-diphosphate delta-isomerase, (ii) manipulation of the lipid metabolism triggered alterations in key enzymes of the carbohydrate metabolism, and (iii) lovastatin treatment was associated with signs of toxicity as reflected by changes in a heterogeneous set of cellular stress proteins involved in functions such as cytoskeletal structure, calcium homeostasis, protease inhibition, cell signaling or apoptosis. These results present new insights into liver gene network regulations induced by lovastatin and illustrate a yet unexplored application of proteomics to discover new targets by analysis of existing drugs and the pathways that they regulate.

Amino Acids↗

PubMed2000

Proteomic analysis of the atrophying rat soleus muscle following denervation.

A proteomic analysis was performed comparing normal rat soleus muscle to denervated soleus muscle at 0.5, 1, 2, 4, 6, 8 and 10 days post denervation. Muscle mass measurements demonstrated that the times of major mass changes occurred between 2 and 4 days post denervation. Proteomic analysis of the denervated soleus muscle during the atrophy process demonstrated statistically significant (at the p < 0.01 level) changes in 73 soleus proteins, including coordinated changes in select groups of proteins. Sequence analysis of ten differentially regulated proteins identified metabolic proteins, chaperone and contractile apparatus proteins. Together these data indicate that coordinated temporally regulated changes in the proteome occur during denervation-induced soleus muscle atrophy, including changes in muscle metabolism and contractile apparatus proteins.

Animals↗

PubMed2000

Proteomics: applications in basic and applied biology.

The rapid evolution of proteomics has continued during the past year, with a series of innovations in the core technologies of two-dimensional electrophoresis and mass spectrometry, and a diversity of productive research programmes. Well-annotated proteomics databases are now emerging in a number of fields to provide a platform for systematic research, with particularly promising progress in clinical applications such as cardiology and oncology. Large-scale quantitative research, comparable in power and sensitivity to that achieved for gene expression, is thus becoming a reality at the protein level.

Databases, Factual↗

PubMed2000

Pharmaceutical proteomics.

Genomics and proteomics are today well established in drug discovery and, in combination with combinatorial chemistry and high-throughput screening, are helping to bring forward an unprecedented number of potential lead compounds. To avoid the generation of bottlenecks downstream in drug development, increasing pressure is arising to integrate these technologies into the development environment. Proteomics has demonstrated proof-of-concept in toxicology as shown by a number of successful applications in mechanistic toxicology and lead selection. The "technology wave" is now starting to impact the clinical phase of drug development. Expected benefits are optimized clinical trials based on the availability of biologically relevant markers of drug efficacy and safety.

Animals↗

PubMed1999

Confirmed identities of proteins from a two-dimensional map of Syrian hamster embryo cells.

The Syrian hamster embryo (SHE) cell transformation assay is widely used to screen chemicals for carcinogenic potential. However, the biochemical mechanisms of transformation in SHE cells are incompletely understood relative to other rodent systems. Thus identification of proteins which change during transformation can provide clues to biochemical mechanisms. Previously, we published a map of SHE cell proteins based on comparisons to other maps. In this report we provide direct sequence analysis of numerous proteins which were previously identified solely by electrophoretic mobility. Protein sequencing verified original spot identifications and extended the range of identified proteins. The updated map will assist in evaluating biochemical mechanisms of morphological transformation in hamster cells.

Animals↗

PubMed1999

Perceptions about substance use among male adolescents in juvenile detention.

Although adolescents in juvenile detention represent a vulnerable population who are exposed to situations that foster risk-taking behaviors, few studies have been conducted with detained adolescents to determine their perceptions regarding substance use. Ethnographic interviews and observations were conducted with 20 male adolescents who resided in a large metropolitan area juvenile detention facility, to discover their substance use beliefs and the decisions they make to continue or discontinue substance use or abuse. The participants described how they initiated substance use and said that they had rarely made active decisions about substance use until they were detained. They explained the decisions they made, while they were in detention, to stop or cut down their substance use after release. They talked about the problems they anticipated when they returned home and how they hoped to balance their resolutions with their reputations and obligations. Time-out in juvenile detention may offer nurses the opportunity to capitalize on the potential readiness of detained adolescents to make resolution decisions regarding risky behaviors. Findings from a similar study conducted with 20 detained adolescent women were reported elsewhere.

Adolescent↗

PubMed1999

Evaluating the outcomes of parent-child family life education.

Conducted in diverse sociocultural communities in Los Angeles County, the project implemented and evaluated a family life education program designed to prevent the negative outcomes of risky sexual behavior. A sample of 251 male and female early adolescents 9 through 14 years of age participated with their parents in this abstinence-based adolescent pregnancy prevention program. The project sought to improve parent-child communications and delay the onset of sex-related behaviors through direct involvement of parents in the education process. Naturally occurring community groups were randomly assigned by site to treatment or delayed treatment conditions in a longitudinal quasi-experimental evaluation design. The evaluation demonstrated significant improvements in communication between parents and children immediately following the intervention; however, these improvements were no longer present 12 months postintervention. The process and outcome evaluation methods employed in the study triangulated qualitative and quantitative data collection and analysis procedures. This combination provided other sources of data than the traditional outcome measures used in most evaluation studies, thus addressing some of the gaps in present program evaluations. Descriptions of the process evaluation, integrated with the outcome data, are intended to heighten nurses' awareness of the importance of this component of research and the rich qualitative data it may yield. The qualitative process components in the project captured the experience of the investigators when they encountered many of the complex challenges that confront researchers who implement and evaluate family life education programs among early adolescents. This experience provided the basis for suggested strategies that nurse clinicians and researchers can use in their work with early adolescents and their parents in clinical-, school-, and community-based settings.

Adolescent↗

PubMed1998

Electron microscopic analysis of gamma-aminobutyric acid and glycine colocalization in rat trigeminal subnucleus caudalis.

Postembedding immunogold methods were used to examine the distribution of gamma-aminobutyric acid (GABA) and glycine and especially their colocalization in glomerular neuronal profiles adjacent to trigeminal primary afferent profiles in lamina II of rat subnucleus caudalis. We found that 60% of the profiles adjacent to the trigeminal primary afferent terminals exhibited colocalization of GABA and glycine. GABA alone was found to localize in 17% of the adjacent profiles. Glycine alone was found to localize in 18% of the adjacent profiles. Of interest, 10% of the trigeminal primary afferent fibers showed glycine localization. All the profiles with colocalization of GABA and glycine were identified as presynaptic axonal terminals, suggesting a possible cumulative effect by these two inhibitory neurotransmitters in presynaptic inhibition. These findings show that GABA and glycine colocalize in a subpopulation of presynaptic axonal terminals within lamina II of the subnucleus caudalis. The possible origins of these axons are discussed, as well as their potential involvement in presynaptic inhibition of orofacial nociception.

Animals↗

PubMed1998

Effect of insoluble extracellular matrix molecules on Fas expression in epithelial cells.

Fas, which functions to initiate a signal causing apoptosis, is expressed in epithelia, thus, suggesting a role in controlling cell number during states of cell and matrix turnover. In view of this, we hypothesized that cell-matrix interactions may be an important determinant of Fas expression in epithelial cells. To investigate this, we examined the effect of insoluble extracellular matrix molecules on Fas expression in murine lung epithelial (MLE) cells, a transformed mouse lung epithelial cell line. We report that 1) insoluble extracellular matrices increased Fas mRNA in a time and concentration-dependent manner; 2) induced increases in Fas mRNA were associated with concomitantly increased Fas protein; and 3) nonspecific adherence to a polylysine substrate did not induce Fas mRNA. Consistent with these findings, Fas-induced apoptosis was significantly enhanced in cultures plated on type IV collagen. Employing rat hepatocytes, we confirmed that the insoluble extracellular matrix also increases Fas expression in primary epithelial cells. By amplifying Fas-mediated apoptosis, these data suggest a mechanism whereby the extracellular matrix regulates the fate of specific epithelial cell populations.

Animals↗

PubMed1998

Analysis of changes in acute-phase plasma proteins in an acute inflammatory response and in rheumatoid arthritis using two-dimensional gel electrophoresis.

Two-dimensional (2-D) gel analysis was used to examine differences in the levels of 19 plasma proteins: before and after an acute inflammatory reaction (parenteral typhoid vaccination) in normal subjects, between rheumatoid arthritis (RA) patients and normals and in RA patients treated with tenidap (120 mg) and piroxicam (20 mg). Typhoid vaccination increased levels of SAA, haptoglobin alpha1, haptoglobin alpha2, haptoglobin beta and alpha1-anti-chymotrypsin but decreased transthyretin and apolipoprotein E. In RA patients, serum amyloid A (SAA), haptoglobin alpha2, haptoglobin beta, alpha1-antichymotrypsin and C3 proactivator levels were elevated while apolipoprotein A-I, apolipoprotein A-IV, transthyretin, Gc-globulin, alpha2-HS glycoprotein, alpha2-macroglobulin and alpha1-B glycoprotein levels were decreased, compared to normals. Compared to piroxicam, tenidap lowered levels of alpha1-antiprotease and SAA but raised the levels of transthyretin, Gc-globulin, alpha2-HS-glycoprotein and alpha2-macroglobulin in RA patients. C-reactive protein (CRP) could not be quantified on 2-D gels but, when measured by rate nephelometry, levels were reduced after treatment with tenidap compared to piroxicam. The general pattern of the acute phase protein response to an acute inflammatory response to typhoid vaccination is similar to that in the chronic inflammatory condition, RA. The impact of tenidap on both positive and negative acute-phase proteins in RA patients could clearly be distinguished from that of piroxicam.

Acute-Phase Proteins↗

PubMed1998

Proteome and proteomics: new technologies, new concepts, and new words.

The goal of proteomics is a comprehensive, quantitative description of protein expression and its changes under the influence of biological perturbations such as disease or drug treatment. Quantitative analysis of protein expression data obtained by high-throughput methods has led us to define the concept of "regulatory homology" and use it to begin to elucidate the basic structure of gene expression control in vivo. Such investigations lay the groundwork for construction of comprehensive databases of mechanisms (cataloguing possible biological outcomes), the next logical step after the soon to be completed cataloguing of genes and gene products. Mechanism databases provide a roadmap towards effective therapeutic intervention that is more direct than that offered by conventional genomics approaches.

Humans↗

PubMed1998

Cholangiocyte-specific rat liver proteins identified by establishment of a two-dimensional gel protein database.

The liver is composed of a variety of cells that form a functional unit involved in uptake, synthesis, metabolism, and secretion. Until recently, most studies examining liver function did not analyze the specific proteins expressed or functions performed by the multiple individual cell types that constitute the hepatic mass. In the last decade, novel isolation methods have been developed that allow the purification of liver cell populations highly enriched in one type of liver cell. Here, we present a detailed two-dimensional (2-D) protein map of rat bile duct epithelial cells (i.e., cholangiocytes) using a recently developed isolation procedure. In addition, we identify 27 major cholangiocyte proteins either by comparison to maps of known rat liver proteins (based on pI and Mr) or by tryptic digestion and microsequencing. Finally, we compare the relative abundance of individual proteins present in cholangiocytes to whole liver as well as hepatocyte-specific proteins. Our results show that cholangiocytes express a unique array of individual proteins. The cholangiocyte 2-D protein pattern is markedly different from that of isolated rat hepatocytes or whole rat liver, with high levels of proteins previously known to be expressed by cholangiocytes (e.g., cytokeratins, actins) as well as protein not previously demonstrated to be expressed at high levels (e.g., annexin V, selenium binding protein). We conclude that this cholangiocyte-derived, 2-D protein map will be a crucial resource for studies directed at our understanding of cholangiocyte physiology and pathobiology.

Animals↗