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Biomedical subjects

M Richardson

Publications and source records attributed to M Richardson.

At least 451 records · Page 25Linked to original sources
PubMedDate not supplied

Human ovarian cancer ascites fluid contains a mixture of incompletely degraded soluble products of fibrin that collectively possess an antiangiogenic property.

Ovarian cancer ascites fluid (OCAF) displayed an antiangiogenic property in a chick chorioallantoic membrane (CAM) assay. This property was attributed in part to angiostatin although angiostatin-free OCAF retained a net antiangiogenic property. Recently, immunopurified fibrin(ogen) degradation products (FDPs) from malignant effusions of VX2 tumor-burdened rabbits exhibited antiangiogenic activity on the CAM. We questioned whether the FDPs of OCAF were also antiangiogenic. FDPs were immunopurified from individual OCAF samples, characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis /western blots, enzyme-linked immunosorbent assays, and CAM assays. FDPs of OCAFs consisted of soluble high molecular weight (MW) fragments (>200 kd; approximately 40% of total FDPs), D-dimer (approximately 180 kd; approximately 37%), fragment D (approximately 90 kd; approximately 15%), and fragment E (approximately 50 kd; approximately 8%); intact fibrinogen was absent. When applied to CAM surfaces (0.5-1.6 mg/10 mL), purified FDPs significantly reduced the area of chorionic capillaries from 90% (in controls) to 47% over a 48-h period; from CAM sections, capillary density was reduced from 60% (controls) to 26%. FDPs prepared from fibrinogen displayed a similar antiangiogenic effect. Further digestion of OCAF FDPs by human plasmin caused degradation of high MW fragments, releasing additional D-dimer, fragment D, and fragment E. Of the fibrinogen-related components, OCAF contained only soluble FDPs (including incompletely digested fibrin fragments). Collectively, these FDPs contributed to the net antiangiogenic property of ascites fluid.

Adult↗
PubMedDate not supplied

Intimal alterations in rabbit aortas during the first 6 months of alloxan-induced diabetes.

Diabetes mellitus is a major risk factor for atherosclerosis. Since endothelial alteration is probably associated with the development of atherosclerosis, we questioned whether morphological evidence of endothelial injury could be observed during the first 6 months of diabetes induced by a single intravenous injection of alloxan in normally fed rabbits compared with age-matched controls. Diabetes (plasma glucose greater than 16 mM) was established by 5 days after alloxan injection. Endothelial alterations consistent with injury, including adhesion of white blood cells, platelets, and fibrin-like material to the endothelial surface, were seen in diabetic rabbit aortas by 2 weeks. These alterations became more severe during the next 6 months. Increased endothelial replication in diabetic vessels was shown by the uptake of tritium-labeled thymidine at 2 weeks and at 3 and 6 months. Hyperplasia of intimal smooth muscle cells progressed during 3 months after treatment. About one third of the diabetic rabbits also showed an elevated plasma cholesterol level, which correlated with increased intimal proliferation but not with endothelial injury or replication. The onset of alloxan-induced diabetes in rabbits is associated with nondenuding endothelial injury and subsequent intimal hypertrophy, changes that are consistent with atherogenesis.

Animals↗
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Proteoglycan distribution in areas of differing permeability to Evans blue dye in the aortas of young pigs. An ultrastructural study.

We studied proteoglycan distribution in areas of spontaneously occurring high and low permeability by TEM examination of ruthenium red-stained sections of the aortic arch of normolipemic and hyperlipemic pigs. We noted granules of two sizes: those smaller than 20 nm contained heparan sulphate, and those from 20 to 50 nm in size contained chondroitin or dermatan sulphate. In the aortas of pigs fed a normal diet, there were significantly more granules of both types in low permeability areas than in areas permeable to Evans blue dye. This is consistent with the theory that glycosaminoglycan provides a component for the control of aortic permeability. In the aortas of pigs fed cholesterol, there was an accumulation of lipid-filled monocytes in areas of high permeability and an increase in proteoglycan granule concentration, suggesting an increase in glycosaminoglycan concentration, which may be the precursor to extracellular lipid deposition.

Animals↗
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Platelet survival and thrombosis.

This study examined the relation among platelet survival, thrombosis, and repeated vessel injury. With the use of 51Cr-labeled platelets, indwelling aortic catheters were shown to reduce platelet survival in rabbits and rats. In rabbits, thrombi were observed mainly at the aortic bifurcation and at the tip of the catheter. The amount of thrombus that formed in rabbits with short and long catheters was similar, but platelet survival was shortened only in rabbits with short and long catheters was similar, but platelet survival was shortened only in rabbits with long indwelling aortic catheters. In rats, the aortic catheters did not cause thrombosis, and platelet survival was shortened significantly in rats with both short and long catheters, but was more pronounced in animals with longer catheters. In both rabbits and rats, long aortic catheters caused more extensive vessel injury than the short catheters and this was associated with greater platelet interaction with the vessel wall. Platelet survival cannot be used as an estimate of thrombus formation, but may reflect the extent and frequency of vessel wall injury. thus, shortened platelet survival may represent increased platelet interaction with the damaged arterial wall and increased platelet consumption.

Animals↗
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Participatory research methods: people with learning difficulties.

The use of participatory research methods as a means of empowering disadvantaged and oppressed groups or individuals has attracted increasing interest in recent years. This article critically examines the use of such methods to empower people with learning difficulties as co-researchers. Emancipatory research would, by definition, be led and processed by people with learning difficulties. For the time being, however, the possibility of engaging people with learning difficulties in truly emancipatory nursing research is regarded as highly problematic, since it assumes empowerment as a precondition. As a step towards emancipatory research, participatory research represents a radical shift in the research process. It may potentially strengthen the voice of people with learning difficulties and enable them to express their views on nursing. The author proposes a methodology which addresses a number of critical issues facing the nurse researcher. It is a step towards developing more liberating and emancipatory methodologies.

Humans↗
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The symbolism and myth surrounding nurses' uniform.

This article addresses nurses' uniform from the perspective of the symbolic, myth, legend and competing discourse. The analysis touches upon why nurses working with people who have learning disabilities discarded the nurses' uniform and why other nurses may consider doing so, particularly if suitable alternatives exist. The analysis draws from various areas of nursing practice, including the nursing of disabled people, elderly people and people with learning disabilities. Nurses' uniform is revealed as a totem of considerable potency such that to wear a uniform in just any setting or context has to be cautioned. The practicalities of protective clothing are addressed. A differentiation is drawn between uniform and protective clothing such that much of the undesirable symbolism associated with uniform may be discarded with a consequent enhancement of the image of the nurse.

Aged↗
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Establishment of a state-supported, specialized home care program for children with complex health-care needs.

Establishment of a systematic approach to home care for children who require complex, technology-dependent care requires a well-thought-out process of collaboration and planning between all parties involved--the family, the professional, and the hospital. The State of Michigan Department of Public Health elected to assist families in taking their children home through a Specialized Home Care Program funded by combined sources that emphasized child care needs first rather than cost savings. This review identifies the development of roles, processes and products, and methods to enhance the discharge planning and home care processes. These processes indicate the need for parent involvement and teamwork with health-care professionals. Refinement of the program is suggested as well as further development of an evaluation component and family assessment tools.

Child↗
PubMedDate not supplied

Marker proteins in the particulate fraction of third-trimester amniotic fluid.

The present clinical evaluation of fetal lung maturity relies largely on the determination of the amniotic surfactant phospholipids phosphotidylglycerol, lecithin, and sphingomyelin, but there are many false negatives as well as false positives among diabetics. The use of other components of lung surfactant, namely, the hydrophobic surfactant proteins (SPs) has long been suggested as an alternative to the classical assay, but tests based on the detection of immunoreactive SP-A have not proved superior or supplanted phospholipid ratios as an index. This report investigates the proteins in a fraction of third-trimester human amniotic fluid (the particulate fraction) enriched in the SP complexes that form the surfactant monolayer. The proteins were analyzed by two-dimensional polyacrylamide gel electrophoresis and visualized by silver staining and immunoblotting. Eight proteins are of particular interest. Three novel proteins (termed AFPP-1, AFPP-4, and AFPP-8) and the alpha-fetoprotein/human serum albumin complex (AFPP-7) can be detected throughout the 28- to 38-week gestational window. The protein that is referred to as AFPP-2 could be identified as SP-A on the basis of immunologic cross-reactivity as well as size and charge characteristics. The time course of appearance of AFPP-2 was also followed in patients with Rh isoimmunization syndrome and was found to be the same as that seen for SP-A. The SP-A was detected as at least five major charged isoforms with multiple subisoforms of different molecular weight and can be distinguished from a related set of proteins (AFPP-5) that appear with a different time course but are possible precursors. Two other proteins (AFPP-3, AFPP-6), which are detectable inconsistently bear some similarity to others reported previously but not extensively characterized. These results define both constant and variable proteins of the particulate fraction of the amniotic fluid and indicate that certain protein isoforms are changing throughout the third trimester. These data enhance the possibility of the utilization of these proteins as markers of lung maturity in conditions such as maternal diabetes.

Amniotic Fluid↗
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Antibodies to the HIV-1 Tat protein correlated with nonprogression to AIDS: a rationale for the use of Tat toxoid as an HIV-1 vaccine.

OBJECTIVES: To investigate which immune parameters, such as antibodies against HIV-1 specificities, or viral parameters, such as p24 antigenemia, are predictive of disease progression. STUDY DESIGN: We performed studies on serum collected from individuals exhibiting two extremes of disease evolution--67 fast progressors (FP) and 182 nonprogressors (NP)--at their enrollment. After a 1- to 2-year clinical follow-up of 104 nonprogressors after their enrollment, we could determine the best serologic predictors for disease progression. METHODS: We investigated levels of antibodies to tetanus toxoid and to HIV antigens including Env, Gag, Nef, and Tat proteins, as well as p24 antigenemia, viremia, CD4 cell count, and interferon-alpha (IFN-alpha) titers in FPs and NPs, and we correlated these data with clinical and biologic signs of progression. RESULTS: p24 Antigenemia, a marker of viral replication, and anti-Tat antibodies were highly and inversely correlated in both groups (P < .001). Furthermore, anti-p24 antibodies and low serum IFN-alpha levels were correlated to the NP versus the FP cohort. Finally, among NPs, only antibodies to Tat and not to the other HIV specificities (Env, Nef, Gag) were significantly predictive of clinical stability during their follow-up. CONCLUSION: Antibodies toward HIV-1 Tat, which are inversely correlated to p24 antigenemia, appear as a critical marker for a lack of disease progression. This study strongly suggests that rising anti-Tat antibodies through active immunization may be beneficial in AIDS vaccine development to control viral replication.

AIDS Vaccines↗
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In praise of number 47.

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Abortion, Spontaneous↗
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Preoperation interviews: a nursing intervention to reduce patients' anxiety.

A quasi-experimental study was conducted to evaluate the effect of preoperative interviews on patients' anxiety levels. A convenience sample of 60 was assigned between two groups of equal size: a treatment group in which subjects were interviewed by a perioperative nurse or a control group in which subjects were not interviewed. All subjects completed state-trait Anxiety Inventory questionnaires. Group comparison using analysis of covariance showed subjects who were interviewed by the perioperative nurse reported significantly less anxiety than control group subjects.

Adolescent↗