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Biomedical subjects

J M Anderson

Publications and source records attributed to J M Anderson.

At least 271 records · Page 15Linked to original sources

Home care management in chronic illness and the self-care movement: an analysis of ideologies and economic processes influencing policy decisions.

Over the past few decades there has been an increasing trend toward self-care and home health care, and one would suspect that these trends will continue into the next century. This article addresses the policy issues that have arisen from a program of research with families caring for a child with a chronic illness in the home and with women who have diabetes mellitus. The argument is developed that, although the home care and self-care movements can be seen as directed toward providing more humanistic care and promoting the independence of the client, the economic and sociopolitical factors that influence their development should not be overlooked. Furthermore, the "cost of caring" must be reckoned with in both human and economic terms. Cost-effective care, in the long run, will mean care that takes into account the social context of health and illness.

Activities of Daily Living↗

The Subunit Structure of Potato Tuber ADPglucose Pyrophosphorylase.

ADPglucose pyrophosphorylase has been extensively purified from potato (Solanum tuberosum L.) tuber tissue to study its structure. By employing a modified published procedure (JR Sowokinos, J Preiss [1982] Plant Physiol 69: 1459-1466) together with Mono Q chromatography, a near homogeneous enzyme preparation was obtained with substantial improvement in enzyme yield and specific activity. In single dimensional sodium dodecyl sulfate polyacrylamide gels, the enzyme migrated as a single polypeptide band with a mobility of about 50,000 daltons. Analysis by two-dimensional polyacrylamide gel electrophoresis, however, revealed the presence of two types of subunits which could be distinguished by their slight differences in net charge and molecular weight. The smaller potato tuber subunit was recognized by antiserum prepared against the smaller spinach leaf 51 kilodalton ADPglucose pyrophosphorylase subunit. In contrast, the anti-54 kilodalton raised against the spinach leaf subunit did not significantly react to the tuber enzyme subunits. The results are consistent with the hypothesis that the potato tuber ADPglucose pyrophosphorylase is not composed of a simple homotetramer as previously suggested, but is a product of two separate and distinct subunits as observed for the spinach leaf and maize enzymes.

Journal Article↗

A quantitative histological study of early clinical and preclinical Alzheimer's disease.

Brains from 70 unselected general hospital necropsy cases aged 60-95 years were surveyed histologically for changes of Alzheimer's disease using Congo Red-Gallocyanin preparations. Counts were made of neurofibrillary tangles in two areas of the neocortex, the hippocampal formation and the substantia innominata. Neurons were counted in the subiculum of the hippocampus, the substantia innominata and the locus coeruleus. In addition, a retrospective enquiry was made concerning the mental health of the patients in the study; cognitive performance was graded on the Global Deterioration Scale (GDS 1-7). Four cases (5.7%) had clinical and pathological changes amounting to early Alzheimer's disease. Tangles were very numerous in all areas and there was a 30% deficit or more of neurons in at least two of the structures counted. Although the diagnosis of Alzheimer's disease was not recorded during life, all had shown signs of early cognitive decline (GDS grades 3-6). A further six cases (8.6%) showed excessive tangle accumulation which may represent preclinical Alzheimer's disease. Tangles were present in the temporal neocortex (Brodmann area 22), whereas they were absent in the remainder of the survey. Tangle density in the hippocampal formation (greater than 50 tangles in a 10 microns section) was also above the baseline level of the majority of cases. However, neuron loss was not widespread in these cases and none had shown evidence of cognitive impairment. The findings confirm that the early stages of Alzheimer's disease commonly occur amongst general hospital necropsies. The emergence of clinical signs of dementia appears to be related to the loss of a critical volume of neurons and not to tangle accumulation alone.

Aged↗

Trapping sheep blowflies using bait-bins.

A bait-bin designed to attract and kill sheep blowflies is described. It is composed of a garbage bin plus lid, attractant and insecticide-treated offal. Fly entry holes are covered with differentiator wire to increase selectivity of kill. Placing bait-bins in preferred habitats of blowflies to optimise kill is outlined and temporal insecticide strategies to increase effectiveness of kill and reduce blowfly resistance are suggested. Preliminary data supporting the effectiveness of bait-bins in reducing blowfly numbers and flystrike in combination with good management practices to reduce sheep susceptibility to flystrike in the arid zone of New South Wales are presented and cost-effectiveness of bait-bins is analysed.

Animals↗

Single lactotroph responses to dopamine, angiotensin II, and culture duration.

Prolactin cells were isolated from male rat pituitaries and studied individually with the reverse hemolytic plaque assay. Plaque area, linearly correlated with radioimmunoassayable prolactin in the culture medium, and percent lactotrophs were measured. A 20-h incubation period markedly enhanced the potency and efficacy of dopamine to inhibit prolactin release compared with an assay conducted on the day of enzymatic dispersion. Frequency histograms of plaque areas showed unimodal distributions after angiotensin II (ANG II)-stimulated prolactin release, with the mode shifting to the right. In contrast, the addition of dopamine to either basal or ANG II-stimulated lactotrophs shifted the mode to the left and decreased the overall range of plaque areas. No clear evidence for discrete subpopulations was generated with this approach; rather, an extensive range of secretory behavior was defined as a continuum, indicating a diverse repertoire of secretory potential in different lactotrophs. Furthermore, comparing lactotrophs from the lateral wings with the central region of the pituitary suggested that lateral cells were less inhibited by dopamine treatment. We conclude that this improved assay allows more precise assessment of the contribution that single lactotrophs make to the population response to dopamine and ANG II.

Angiotensin II↗

Morphologic characteristics of adsorbed human plasma proteins on vascular grafts and biomaterials.

Protein adsorption on the surfaces of clinically significant prosthetic vascular graft materials from human whole blood was independent of plasma concentration as determined morphologically by use of immunogold labels. Some proteins, such as fibrinogen, adsorbed in a multilayer pattern on expanded polytetrafluoroethylene and had a preference for particular surface features of the polymer. Other proteins, such as Hageman factor (factor XII), showed diffuse adsorption patterns. Physiologically significant proteins that have not been well studied, such as immunoglobulin G and factor VIII, adsorbed readily to the surface of expanded polytetrafluoroethylene. This finding may be significant since adsorbed proteins may activate coagulation mechanisms and immunologic responses, including platelet and monocyte adhesion and activation. Any human blood protein for which an antibody has been developed can be studied by use of this technique.

Adsorption↗

Protein adsorption and cellular adhesion and activation on biomedical polymers.

The design and development of new biomedical polymers for clinical application in devices, prostheses, and artificial organs requires a basic and fundamental understanding of biological interactions with biomedical polymers. Efforts in our laboratory have been directed towards appreciating the humoral and cellular interactions which govern protein adsorption and cellular adhesion and activation on biomedical polymers. Information and data are presented on protein adsorption from whole human blood, complement activation and receptors, and monocyte/macrophage adhesion and activation with growth factor release. Supported by experimental evidence, concepts regarding protein/polymer, cell/polymer, cell/protein/polymer, and cell/cell interactions as they are related to in vivo events are presented.

Adsorption↗

Adsorption of Hageman factor (factor XII) and other human plasma proteins to biomedical polymers.

Protein adsorption to surfaces occurs whenever blood comes into contact with biomaterials, prosthetic devices, and artificial organs. The plasma protein Hageman factor (factor XII) present at the interface between blood and foreign surfaces can be qualitatively and quantitatively detected after in vitro perfusion of anticoagulated human blood through important biomedical polymers. We have determined protein adsorption by a modified radioimmunoassay and by scanning electron microscopy using immunogold labeling techniques. The materials used included vascular graft materials (Dacron and expanded polytetrafluoroethylene) and the National Heart, Lung, and Blood Institute-Devices and Technology Branch reference materials polydimethylsiloxane, polyethylene, and silicone rubber. Factor VIII-von Willebrand factor, another trace plasma protein, and other plasma proteins such as fibrinogen, immunoglobulin G, albumin, fibronectin, and hemoglobin were also detected at the blood-contacting surface. At physiologic flow rates, the adsorption of these proteins from the circulating blood to the surface of these materials appears to be a function of time, with certain materials, as well as of the physical and chemical characteristics of the material surface. Hageman factor adsorption to surfaces, quantified under static conditions, occurs at nanogram concentrations. These data suggest that trace proteins, such as those important in the activation of the coagulation cascade, can significantly affect the blood compatibility or thrombogenicity of an implanted device.

Adsorption↗

Residency training in physical medicine and rehabilitation. I: Clinical and didactic experience.

A survey was conducted to determine the type of clinical and didactic training experience that was provided to resident trainees in physical medicine and rehabilitation (PM&R) in the 1987-1988 academic year. Chief residents from 43 (61%) of the 70 PM&R programs accredited by the Accreditation Council for Graduate Medical Education responded. According to respondents, the programs averaged 12.6 residents. The residents spent an average of 18.5 months on an inpatient bedservice, 12.6 months on outpatient exposures, and the remainder of the time attending other clinical experiences and didactic training. Forty percent of those responding reported that their programs required in-house call in postgraduate years (PGYs) 2 through 4, and 53% of the programs required no in-house call during the same clinical years. Seven percent of the programs required in-house call in PGYs 2 and 3, but none in PGY 4. The average time spent in electrodiagnostic studies was 7.6 months (range = 2 to 19 months). Electromyography exposure by completion of PGY 4 also varied widely, from 40 to 500 studies. Resident trainee exposure to inpatient and outpatient spinal cord injury, closed head injury, pediatric rehabilitation, sports medicine, and geriatric medicine, and rehabilitation fellowship positions being offered through the responding PM&R residency training programs were also surveyed. Some instances of apparent program imbalances or inadequate training which could reduce the scope of a resident's educational experience were noted.

Internship and Residency↗

Brain injury obscured by chronic pain: a preliminary report.

Chronic pain patients and brain injured patients frequently exhibit anxiety, depression, perseveration, and fixed ideation about their injuries. Both populations also frequently suffer from decreased attention, impaired concentration, easy fatigability, personality changes, impaired relationships with family and friends, and difficulty maintaining a job. In cases where chronic pain coexists with traumatic brain injury, the brain injury is often obscured. Risk factors which should alert the medical team to possible coexisting brain injury include history of loss of consciousness at original injury, history of trauma to the head, whiplash injury to the neck, multisystem trauma, and admission of memory or attention deficits by the patient. When any of these risk factors are present, we have found that formal examination of cognitive function is required to explore the potential of coexisting brain injury; if pain is a prominent clinical feature, residual cognitive sequelae of mild brain injury is easily masked. Specific testing of attention, new learning ability, constructional ability, and higher cognitive functions are most helpful in this population, and they need to be included in the mental status examination when concomitant brain injury is suspected. In our study, seven patients were found to have undiagnosed brain injury in a series of 67 consecutive patient referrals to our pain rehabilitation program. Treatment failure is high in this subgroup of pain patients unless treatment is directed toward the sequelae of both brain injury and chronic pain.

Adult↗

Phosphorylation of the tight-junction protein ZO-1 in two strains of Madin-Darby canine kidney cells which differ in transepithelial resistance.

A comparison was made of the phosphate content of the tight-junction-specific protein ZO-1 in two strains of Madin-Darby canine kidney cells which differ in transepithelial resistance, a parameter reflective of tight-junctional permeability. Analysis revealed that the ZO-1 from the low-resistance strain contained approximately twice as much phosphate as that from the high-resistance strain.

Animals↗

The encoded primary sequence of a rice seed ADP-glucose pyrophosphorylase subunit and its homology to the bacterial enzyme.

Rice seed ADP-glucose pyrophosphorylase cDNA clones were isolated by screening a lambda expression library prepared from rice endosperm poly(A+) RNA with a heterologous antibody raised against the spinach leaf enzyme and subsequently by nucleic acid hybridization. One cDNA plasmid, possessing about 1650 nucleotides, was shown by both DNA and RNA sequence analysis to contain the complete ADP-glucose pyrophosphorylase coding sequence of 483 amino acids. The primary sequence displayed a putative leader peptide presumably required for transport of this nuclear encoded protein into the amyloplasts, a differentiated starch containing plastid. The leader peptide, however, showed little sequence homology with transit peptides displayed by other known nuclear encoded proteins localized in the chloroplasts. A comparison of the primary sequence of the putative mature subunit to the Escherichia coli pyrophosphorylase showed two regions displaying significant homology. These two conserved regions contain residues shown previously to be essential for the allosteric regulation and catalytic activity of the E. coli enzyme. Differences in the primary sequences of the plant and bacterial enzyme may reflect the distinct nature of the allosteric effectors that control these enzymes.

Amino Acid Sequence↗

Establishment of a leukemic cell model for studying human pre-B to B cell differentiation.

Reproducible models for examining early stages of human B cell differentiation are poorly developed. We now describe the establishment and characterization of a novel human leukemic cell line that recapitulates the pre-B to B cell stage of differentiation. This cell line, designated BLIN-1, was initially established in tissue culture medium containing low m.w. B cell growth factor, and consistently shows a dependency on this cytokine for optimal growth at low density. BLIN-1 cells have a 9p chromosomal abnormality, identical to the abnormality present in the leukemic blasts from the patient's original bone marrow aspirate. The immunologic phenotype of BLIN-1 is consistent with a cell arrested at the pre-B cell stage of development. Analysis of Ig gene rearrangement and Ig expression in a series of BLIN-1 subclones show that the cells spontaneously rearrange kappa light chain genes, leading to the differentiation of surface kappa-negative pre-B cells into surface kappa-positive B cells. The BLIN-1 cell line is, to our knowledge, the first defined human model for examining this critical developmental stage in human B cell ontogeny. As such, it offers a unique resource for examining variables influencing onset of kappa L chain gene rearrangement and expression.

B-Lymphocytes↗

Plasma protein adsorbed biomedical polymers: activation of human monocytes and induction of interleukin 1.

These studies involved the evaluation of human monocyte/macrophage activation by biomedical polymers coated with human blood proteins. The biomedical polymers were polyethylene, polydimethylsiloxane, woven Dacron fabric, expanded polytetrafluoroethylene, Biomer, and tissue culture treated polystyrene as the control. They were adsorbed with human blood proteins: albumin, fibrinogen, fibronectin, hemoglobin, and gamma globulin. The protein adsorbed polymers were evaluated for their potential to activate the monocyte/macrophage cellular population in vitro as assessed by the induction of the monocyte/macrophage inflammatory mediator, Interleukin 1 (IL1). Suppression of IL1 was observed when protein adsorbed polymers were compared to the appropriate protein adsorbed control. Protein adsorbed polymers, when compared to polymers without protein adsorption, stimulated IL1 production. The data presented in this manuscript show the level of induction and secretion of IL1 was dependent on the biomedical polymer and the protein adsorbed, as well as the requirement of lipopolysaccharide. These results show differential interactions occur between the proteins, monocytes/macrophages, and biomedical polymers which alter activation and induction of IL1.

Animals↗

In vitro stimulation of fibroblast activity by factors generated from human monocytes activated by biomedical polymers.

Biomedical polymers used in constructing implantable artificial devices may affect host responses to the material and ultimately contribute to the success or failure of a device via mechanisms of cell-polymer interactions. Human peripheral blood monocytes (MO) cultured in the presence of several such biomedical polymers released factors that stimulated fibroblast proliferation and/or collagen synthesis. The factors that stimulated fibroblast proliferation were differentially released from monocytes cultured in the presence of Dacron, polyethylene, expanded polytetrafluoroethylene (ePTFE), polydimethylsiloxane, and polystyrene (control). Supernatants obtained from monocytes cultured in the presence of Biomer, a segmented polyetherurethane, were unable to stimulate fibroblast proliferation. However, supernatants from all cultures, including MO-Biomer cultures, were able to induce collagen production from the same target fibroblasts. These same supernatants also were shown to contain interleukin 1 (IL1) activity. Neutralization of the fibroblast stimulatory potential (FSP) activity with antibodies directed against human IL1 and human PDGF demonstrated that IL1 and not PDGF was responsible for the FSP activity. Results of this study show that by affecting macrophage activation, different biomedical polymers can affect host biocompatibility responses by altering fibroblast proliferation and function.

Adult↗

Generation of IL-1-like activity in response to biomedical polymer implants: a comparison of in vitro and in vivo models.

Of the many factors determining host biocompatibility responses to implanted biomedical polymers, the cellular interactions at the tissue/material interface have been recognized to be some of the most important. The present study has combined results both from an in vitro cell culture system and from an in vivo animal model to examine this host response. In vitro results suggest that a variety of polymer materials can differentially activate human monocytes to produce a protein(s) having different biological activities. The polymers tested induce the production of the regulatory inflammatory protein interleukin 1 as well as a factor that enhances fibroblast proliferation and collagen synthesis. The observed activities of these factors appear to be related but not identical, and are dependent upon the specific polymer. Evaluation of exudate and tissue responses to these same polymer materials in an in vivo model are also presented. Both in vitro and in vivo results support the hypothesis that monocyte/macrophage activation with subsequent synthesis of regulatory factors such as interleukin 1 plays a significant role in determining the host response to biomedical polymer implants.

Adult↗

Acute histopathological response to a new biodegradable polypeptidic polymer for implantable drug delivery system.

This article deals with the in vivo evaluation of a new class of synthetic polypeptides, the poly[(tert-butyloxycarbonylmethyl) glutamates], POMEG, as an injectable or implantable drug delivery system. Three different polymers, varying in their degree of esterification, were extruded either with or without progesterone, and finally implanted in rats up to 14 days. Histologic evaluation of the implant sites show evidence of the good biocompatibility of these polymers. In addition, the description of their in vivo behavior, based on microscopic observation of the implanted POMEG rods, enables one to appreciate their potential as a drug delivery system for short- or long-term therapy.

Animals↗