PubMed Health⌕ Search

Biomedical subjects

C E Robinson

Publications and source records attributed to C E Robinson.

At least 19 recordsLinked to original sources
PubMed2007

The role of computed tomography in terminal ballistic analysis.

Terminal ballistics concerns the science of projectile behaviour within a target and includes wound ballistics that considers what happens when a projectile strikes a living being. A number of soft tissue ballistic simulants have been used to assess the damage to tissue caused by projectiles. Standard assessment of these materials, such as ballistic soap or ordnance gelatine, requires the block to be opened or that a mould to be made to visualize the wound track. This is time consuming and may affect the accuracy of the findings especially if the block dries and alters shape during the process. Therefore, accurate numerical analysis of the permanent or temporary cavity is limited. Computed tomography (CT) potentially offers a quicker non-invasive analysis tool for this task. Four commercially purchased ballistic glycerine soap blocks were used. Each had a single firearm discharged into it from a distance of approximately 15 cm using both gunshot and shotgun projectiles. After discharge, each block was imaged by a modern 16 slice multi-detector CT scanner and analysed using 3-D reconstruction software. Using the anterior-posterior and lateral scout views and the multi-plane reconstructed images, it was possible to visualize the temporary cavity, as well as the fragmentation and dispersal pattern of the projectiles, the distance travelled and angle of dispersal within the block of each projectile or fragment. A virtual cast of the temporary cavity can be also be made. Multi-detector CT with 3-D analysis software is shown to create a reliable permanent record of the projectile path allowing rapid analysis of different firearms and projectiles.

Forensic Ballistics↗
PubMed2004

Inactivation of enteric microbes in water by electro-chemical oxidant from brine (NaCl) and free chlorine.

Oxidant solutions of mostly free chlorine can be electrochemically produced on-site from brine (NaCl) solution and used to disinfect water at the household or community level. In this study electrochemical oxidant (ECO) from brine and free chlorine were evaluated under laboratory conditions for inactivation of test microbes. Purified suspensions of Escherichia coli, the rugose strain of Vibrio cholerae, Clostridium perfringens spores, MS2 coliphage and Cryptosporidium parvum oocysts were treated with 2 mg/L or 5 mg/L solutions of ECO or free chlorine at 5 degrees C and 25 degrees C and pH 6, 8, and 10 (pH 7 and 25 degrees C only for C. parvum oocysts) for contact times <60 min. Under nearly all conditions, inactivation kinetics were more rapid for E. coli, V. cholerae, C. perfringens spores and MS2 coliphage with ECO than with free chlorine. ECO reduced E. coli, V. cholerae and MS2 by >4 log10 within 30 min and C. perfringens spores by >2 log10 within 10 min at pH 8 and 25 degrees C. Contrary to previous results, however, C. parvum oocysts were not inactivated by ECO, and the reasons for this difference are uncertain. The on-site electrolytic generation of oxidants from brine provided a convenient and inexpensive disinfectant containing free chlorine that was effective against many enteric microbes, for the treatment of household and community drinking-water supplies worldwide. However, the effectiveness of such oxidants for inactivating C. parvum oocysts was variable and sometimes ineffective.

Animals↗
PubMed1999

Determination of protein carbonyl groups by immunoblotting.

Free radical-mediated oxidation of proteins results in the formation of carbonyl groups in quantities that reflect the intensity of the oxidative stress. We have developed an immunochemical technique for the quantification of carbonyl groups in protein samples prepared from small tissue samples and cell cultures. Protein samples were slot-blotted onto a polyvinylidene difluoride membrane, which was sequentially treated with 2,4-dinitrophenylhydrazine (DNPH), a primary antibody specific for the 2,4-dinitrophenol group, and a peroxidase-labeled second antibody. After the blots were developed with a chemiluminescent substrate and exposed to X-ray film, the level of immunostaining was quantitated by densitometry. Using oxidized bovine serum albumin as a standard and loading 5 microg of protein per slot, the minimum detectable carbonyl content was approximately 60 pmol carbonyl/mg protein. When necessary, nonspecific staining by noncarbonyl constituents in complex sample matrices was accounted for by using sodium borohydride-treated blanks. Results by the new method were highly correlated (r = 0.932, P < 0.0001) with those of the standard DNPH-based spectrophotometric technique. The coefficient of variation at a carbonyl level of 1.5 nmol/mg protein was 9.7%. The utility of this new method was demonstrated by measuring protein oxidation in cultured human colon cells (SW620) that were briefly exposed to H2O2.

Cells, Cultured↗
PubMed1999

A corepressor and chicken ovalbumin upstream promoter transcriptional factor proteins modulate peroxisome proliferator-activated receptor-gamma2/retinoid X receptor alpha-activated transcription from the murine lipoprotein lipase promoter.

Complex physiological stimuli differentially regulate the tissue-specific transcription of the lipoprotein lipase (LPL) gene. A conserved DNA recognition element (-171 to -149 bp) within the promoter functions as a transcriptional enhancer when bound by the peroxisome proliferator-activated receptor-gamma2 (PPARgamma2)/retinoid X receptor alpha (RXRalpha) heterodimer, but serves as a transcriptional silencer in the presence of unidentified double and single stranded DNA-binding proteins. To address this apparent paradox, the current study examined the effect of two classes of candidate comodulatory proteins, COUP-TF (chicken ovalbumin upstream promoter transcriptional factor) and the corepressor SMRT (silencing mediator of retinoic acid receptor and thyroid receptor). The expression of COUP-TF was detected by Western and Northern blots in a preadipocyte 3T3-L1 cell model during periods corresponding to increased LPL transcription. Cotransfection of COUP-TF expression constructs in the renal epithelial 293T cell line significantly increased transcription from the LPL promoter in synergy with PPARgamma2/RXRalpha heterodimers. The COUP-TFII (ARP-1) protein specifically bound the LPL PPAR recognition element inelectromobility shift assays and interacted directly with the ligand-binding domain of PPARgamma in pull-down experiments. In contrast, cotransfection of SMRT repressed PPARgamma2/ RXRalpha-mediated LPL transcription in the absence or presence of COUP-TFII (ARP-1). The interaction between PPARgamma2 and SMRT localized to the receptor-interactive domain 2 (amino acids 1260-1495) of the SMRT protein based on cotransfection and pull-down assays. These in vitro data indicate that COUP-TF proteins and SMRT modulate PPARgamma-mediated LPL transcription in the 293T cell line.

3T3 Cells↗
PubMed1998

DNA bending is induced by binding of the peroxisome proliferator-activated receptor gamma 2 heterodimer to its response element in the murine lipoprotein lipase promoter.

The peroxisome proliferator activated receptor gamma 2 (PPAR gamma 2) is a critical transcriptional regulator of adipogenesis. Lipoprotein lipase is one of the earliest genes induced following exposure of pre-adipocytes to PPAR gamma 2 ligands such as the thiazolidinediones. A unique PPAR gamma 2 DNA recognition element was mapped to the region between -171 to -149 bp of the murine LPL promoter, based on transfection analysis of deletion constructs and gel retention assays using bacterially expressed, affinity purified recombinant proteins. Circular permutation analysis determined that binding of the PPAR gamma 2/retinoic acid X receptor (RXR) heterodimer to its LPL promoter recognition element induced DNA bending at an angle of approximately 46 degrees. Parallel studies using an optimal PPAR recognition element obtained a comparable bending angle of 56 degrees. This is the first demonstration that binding of a PPAR protein to its recognition element causes a distortion of the DNA configuration. It indicates that PPAR gamma 2 utilizes a common mechanism shared by other nuclear hormone receptor proteins reported to induce bending at their DNA binding sites.

Animals↗
PubMed1998

Nuclear hormone receptors and adipogenesis.

Adipocytes provide a model cell system for exploring the complexities of nuclear hormone receptor transcriptional regulation. Adipocytes produce lipid and cholesterol metabolites which can serve as activating ligands for many of the classic and "orphan" nuclear hormone receptors. At the same time, nuclear hormone receptors directly control adipocyte commitment. The recently described nuclear hormone receptor coactivators and corepressors provide an additional level of complexity to this system. This review emphasizes available in vitro and in vivo models and discusses them in the context of current controversies and future experimental directions.

Adipose Tissue↗
PubMed1997

CAAT/enhancer binding proteins directly modulate transcription from the peroxisome proliferator-activated receptor gamma 2 promoter.

The CCAAT/enhancer binding proteins (C/EBPs) and the peroxisome proliferator-activated receptors (PPARs) together regulate adipogenesis. The current work uses co-transfection studies to examine the C/ EBP dependence of PPAR gamma 2 transcription. Both C/ EBP alpha and C/EBP delta expression vectors activated transcription from a PPAR gamma 2 promoter/luciferase expression vector by 5-6 fold in UMR106 cells. The simultaneous transfection of the C/EBP homologous protein (CHOP) (also known as growth arrest DNA damage protein 153 or gadd153) inhibited this C/EBP-dependent activation in a concentration dependent manner. The CHOP protein is known to heterodimerize with other C/EBP proteins to form transcriptionally inactive complexes. Mutation of the two C/EBP DNA recognition elements at -340 bp and -327 bp within the PPAR gamma 2 promoter reduced the inductive effects of both C/EBP alpha and C/EBP delta. These findings demonstrate that proteins within the C/EBP family directly modulate transcription from the PPAR gamma 2 promoter.

Animals↗
PubMed1997

Regulation of neutrophils in ulcerative colitis by colonic factors: a possible mechanism of neutrophil activation and tissue damage.

The mucosal injury of active ulcerative colitis (UC) could involve enhanced migration and activation of neutrophils (PMNs). Because, in vitro, PMNs from patients with UC appear normal and are not therefore a likely cause for the enhancements, we hypothesized an abnormal colonic milieu. We previously found that factors in the UC colonic milieu markedly increase production of reactive oxygen species (ROS) by control PMNs. We now hypothesize that these factors also regulate PMN surface integrins, that regulation of UC PMNs is different than that of control PMNs, and that the integrin regulation is consistent with the ROS regulation. Using rectal dialysis, we sampled the colonic milieu in patients with active UC, in patients with inactive UC, and in control subjects. We monitored a key PMN adhesion molecule, CD11b. When control PMNs were tested, active UC rectal dialysate was almost as effective (+115%) as N-formyl-methionyl-leucyl-phenylalanine (+132%) in up-regulating CD11b. When inactive UC PMNs were tested, baseline CD11b was 50% higher than that for control PMNs. In contrast, rectal dialysates failed to up-regulate CD11b of inactive UC PMNs and in fact down-regulated CD11b. Preincubating control PMNs with UC rectal dialysates converted their CD11b response to PMN activators from up-regulation to down-regulation, mimicking inactive UC PMNs. Changes in intracellular calcium levels paralleled these changes in CD11b. Rectal dialysate-induced changes in both CD11b and calcium paralleled our previous findings on rectal dialysate-induced changes in ROS production. Thus the net overall effect of factors in the colonic milieu is a consistent and predictable regulation of PMN function--proinflammatory in UC, anti-inflammatory in control subjects. These factors may be a critical part of the pathophysiology of UC.

Adult↗
PubMed1997

Constant infusion and bolus injection of stable-label tracer give reproducible and comparable fasting HGO.

We have investigated the reproducibility of fasting hepatic glucose output (HGO) estimates by use of isotope dilution methodology of stable-label tracers. Six normal subjects were studied on two occasions 1 wk apart. After an overnight fast, the subjects received a bolus injection of 7 mg/kg of [U-13C]glucose and, simultaneously, a primed constant infusion of 0.05 mg.kg-1.min-1 of [6,6(-2)H]glucose. The bolus injection provided one estimate of HGO (HGOBOL), and the constant infusion provided two estimates of HGO, namely, HGO at 2 h (HGOINF2) and HGO at 4 h (HGOINF4), both with the assumption of steady-state conditions. All estimates were similar in value; HGOBOL was highest, followed by HGOINF2 and HGOINF4 [2.30 +/- 0.11 (SE), 2.17 +/- 0.12, and 2.01 +/- 0.13 mg.kg-1.min-1]. The constant infusion gave highly reproducible results. In the case of HGOINF2, the within-subject coefficient of variation (CV) was only 3% compared with 5% of HGOINF4. The reproducibility of HGOBOL was comparable with the within-subject CV of 7%. We conclude that a constant infusion and a bolus injection of stable-label tracer give reproducible and comparable estimates of HGO.

Adult↗
PubMed1996

Analysis of the native murine bone morphogenetic protein serine threonine kinase type I receptor (ALK-3).

The bone morphogenetic proteins, members of the transforming growth factor-beta cytokine family, induce the osteoblast phenotype and promote osteogenesis in the bone marrow stroma. Simultaneously, these cytokines inhibit other mesodermal differentiation pathways, such as adipogenesis and myogenesis. The receptors for the bone morphogenetic proteins belong to a family of transmembrane serine/ threonine kinase TGF beta type I and type II receptor proteins. In man, these include the activin receptor like kinase-3 (ALK-3), a type I receptor protein. We have used a polyclonal antibody to examine the expression of the native murine ALK-3 protein in murine tissues and bone morphogenetic protein-responsive cell lines. On Western blot analyses, we found that the native 85 kDa native ALK-3 protein was expressed in a number of murine tissues; protein and mRNA levels did not necessarily correlate. Two bone morphogenetic protein-responsive cell lines, BMS2 bone marrow stromal cells and C2C12 myoblasts, expressed the ALK-3 protein constitutively. Cell differentiation was accompanied by modest changes in ALK-3 protein levels. Immunoprecipitation of the ALK-3 protein cross linked to [125I] BMP-4 revealed two major receptor complexes of approximately 90 kDa and 170 kDa in size. Biotin surface-labeling experiments revealed that the 85 kDa ALK-3 protein was constitutively associated with a novel 140 kDa surface glycoprotein. Deglycosylation reduced the protein's size to 116 kDa, comparable in size to that of the recently described BMP type II receptor. These findings support the current model that BMP interacts with a pre-existing complex consisting of a type I and type II receptor protein.

Animals↗
PubMed1996

The function of adipocytes in the bone marrow stroma: an update.

The adipocyte is the most abundant stromal cell phenotype in adult human bone marrow. Four hypotheses may explain their function. First, adipocytes may serve a passive role, simply occupying excess space in the bone marrow cavity. Second, they may play an active role in systemic lipid metabolism. Third, adipocytes may provide a localized energy reservoir in the bone marrow. Or fourth, marrow adipocytes may contribute directly to the promotion of hematopoiesis and influence osteogenesis. This article reviews recent findings concerning bone marrow adipocyte morphology and physiology, the transcriptional and cytokine mechanisms regulating their differentiation, and the interrelationships existing between bone marrow adipocytes, hematopoiesis, and osteogenesis. Overall, these data lend support to a "plastic" model of bone marrow stromal cell differentiation; adipocytes may share common functions with stromal stem cells, osteoblasts, and hematopoietic supportive cells.

Adipocytes↗
PubMed1996

Peroxisome proliferator-activated receptor-gamma activation by thiazolidinediones induces adipogenesis in bone marrow stromal cells.

The thiazolidinediones improve insulin sensitivity in animal models and have promise as potent oral antidiabetic agents. Their clinical use has been limited because of the resulting anemia and cardiac hypertrophy. Some compounds of this class have been reported to induce bone marrow fat accumulation in animals, and this effect could account for the observed anemia. We examined the biological mechanism contributing to this phenomenon. The thiazolidinediones BRL49653 and pioglitazone induced adipocyte differentiation in the BMS2 bone marrow stromal cell line in a dose- and time-dependent manner. These actions were further enhanced by the presence of glucocorticoids and other adipogenic agonists. The thiazolidinediones increased the mRNA levels of adipocyte-specific genes, including that of their receptor, the peroxisome proliferator-activated receptor-gamma (PPAR gamma). In contrast, mRNA levels of genes encoding other PPAR family members (PPAR alpha, PPAR delta, or NUC-1) were unchanged or decreased. Thiazolidinedione treatment of primary bone marrow stromal cells elicited a comparable dose-dependent response. Using a polyclonal antibody, PPAR gamma was detected in protein lysates from adipose-rich bone marrow. Thus, thiazolidinedione directly regulates bone marrow stromal cell differentiation; induced PPAR gamma expression may play a key regulatory role in this process.

Adipocytes↗
PubMed1995

Cloning and characterization of the murine activin receptor like kinase-1 (ALK-1) homolog.

Multiple serine/threonine kinases were detected in a bone marrow stromal cell line. One of these, the murine activin receptor like kinase-1 (ALK-1) homolog was cloned and sequenced. The expressed recombinant protein (62 kDa) was consistent in size with that predicted by the cDNA (58.6 kDa). On Western blots, a goat polyclonal antibody detected the native ALK-1 protein in bone marrow stromal cells, lung, brain, kidney and spleen. Two protein species of 60 kDa and 72-76 kDa were detected. Glycosylation events or alternative splicing may account for the larger protein specie.

Activin Receptors↗
PubMed1990

DNA sequence analysis of an abl-related gene in the blow fly, Calliphora erythrocephala.

The Ceabl locus is a member of a small family of abl-related sequences in C. erythrocephala. The catalytic, SH2 and SH3 domains of the Ceabl-encoded protein show greater than 75% sequence identity to vertebrate abl protein tyrosine kinases and greater than 95% identity to the D. melanogaster abl polypeptide. Ceabl diverges from the vertebrate proteins, however, at the extreme amino terminus, near the beginning of the vertebrate abl exon involved in differential splicing. The carboxyl region shows no detectable similarity to the vertebrate abl proteins, while identity to Drosophila abl falls to 55%. Regions conserved between the two dipteran genes revealed no strong similarities to other proteins in the Genbank and EMBL databases.

Amino Acid Sequence↗
PubMed1985

The molecule-group schema of memory: storage, recognition and retrieval.

A new schema, the molecule-group schema, explains memory storage, recognition and retrieval. The schema consists of three postulates about molecular specificity, grouping, and diffusion. In the schema, the physical memory trace consists of a stable group of different kinds of highly specific molecules. The schema is intended to provide an alternative to the widely known synaptic-change schema, in which it is assumed that changes of synaptic efficacies constitute the memory trace. The new schema is used to develop a particular model of memory. In the model, recognition occurs when specific intracellular "endotransmitters" react with complementary "endoreceptors" in the same cell. Retrieval, modelled as the process whereby memory causes the recurrence of a previously experienced pattern of neural activity, occurs when a group of pools of endotransmitters, located within an intracellular memory organelle, is released, allowing the endotransmitters to diffuse to the periphery of the cell body. The model suffices to explain long-term and short-term memory of events as well as innate memory.

Animals↗
PubMed1984

Polyarthritis associated with gastric carcinoma.

In a 68-year-old man who had polyarthritis associated with gastric carcinoma surgical resection of the tumour was accompanied by prompt resolution of the arthritic syndrome. In 11 years of follow-up the arthritis has remained in complete remission and there has been no recurrence of the carcinoma. An awareness that polyarthritis may be a presenting manifestation of an underlying carcinoma may, especially in an elderly person, lead to early recognition and treatment of the malignant disease.

Adenocarcinoma↗
PubMed1984

Application of a new rating scale of brain dysfunction to monitoring rehabilitation in 65 patients with severe head injury.

Sixty-five patients with severe head injury sustained in motor vehicle accidents (MVA) are the subject of the prospective investigation. For assessment of results of a particular treatment, planning of long-range management and predicting the outcome in terms of employment or of self-care, it is essential to monitor sequentially the progress of recovery. A comprehensive semiquantitative rating Scale g was developed and its application during repeated examinations demonstrated. The Scale g is open-ended, as it allows physicians and investigators in the health field to produce their own schedules of any disability provided that seven levels of that particular dysfunction are defined according to the principles of Scale g. The progress of recovery in motor deficits, dysarthria, mental impairment, and self-care was assessed using appropriate schedules according to Scale g in 65 inpatients at their first admission to the rehabilitation center and at their discharge. The change was made evident by showing patients' advancement, if present, to the higher functional level. It was estimated at the time of discharge that 23.1% can be expected to return to full-time employment, 38.5% are likely to perform part-time lesser work, 13.8% may be able to perform certain, non remunerative chores at home, 24.6% would not be able to do any work--about one-third of them will permanently require long-care facility.

Activities of Daily Living↗