Biomedical subjects
Publications and source records attributed to H James.
The size of the pressure sore problem in the community is virtually unknown. Problems specific to the community include lack of observation, poor nutrition and lack of resources. District nurses need supportive services, multidisciplinary backing, education and equipment.
Chronic myelogenous leukaemia (CML) is associated with a translocation between the ABL and BCR genes on chromosomes 9 and 22, t(9;22). The resulting transcription and translation products, bcr-abl mRNA and p210bcr-abl, are unique to the malignant cells and as such are ideal targets for specific chemicals or drugs. We have designed hammerhead ribozymes to cleave the two predominant forms of bcr-abl mRNA, b2a2 and b3a2. Synthetic bcr-abl RNA substrates were cleaved by the ribozymes in vitro, but so was a wild-type abl RNA sequence. bcr RNA was not cleaved in vitro and mutant ribozymes showed no cleavage activity. Ribozymes designed to cleave 9 nucleotides (nt) from either of the fusion points were non-specific for the bcr-abl substrate, but a ribozyme designed to cleave 3 nt upstream of the b3a2 fusion point was specific for b3a2 RNA. However, this ribozyme was less efficient than the others. The shortening of one of the ribozymes arms from 10 nt to 4 nt resulted in a ribozyme that was more specific without losing any efficiency. We conclude that it is possible to specifically cleave bcr-abl RNA in vitro by using hammerhead ribozymes.
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The size of the pressure sore problem in community patients is virtually unknown and further research is necessary in this area. Pressure sore prevention can be more difficult in community patients because of problems specific to that sector such as lack of observation, reliance on carers, poor nutrition and lack of resources. District nurses need supportive services, multidisciplinary backing, education and equipment if they are to take the lead in this area.
OBJECTIVE: To determine if IgM and IgA anticardiolipin (aCL) antibodies require beta 2 glycoprotein I (beta 2-GPI) as a cofactor for antibody binding. METHODS: Sera were selected from 7 patients with systemic lupus erythematosus (SLE), 6 of whom had high IgM and 6 high IgA aCL antibody binding. Control sera were obtained from 2 healthy individuals with no aCL antibodies. Serum proteins were initially separated by sepharose CL6B get filtration chromatography, and IgM was further purified by affinity chromatography with mannan binding protein. IgA was isolated from CL6B filtrate by jacalin lectin affinity chromatography. Levels of beta 2-GPI in the immunoglobulin preparations were determined by antigen capture ELISA: Anticardiolipin antibody binding IgM and IgA was examined by ELISA with and without the addition of beta 2-GPI (10 micrograms/ml) or 4% normal human serum and expressed in optical density units (OD). RESULTS: beta 2-GPI was required as a cofactor for IgM aCL antibody binding in 4 to 6 patients with SLE. In these, antibody binding to cardiolipin increased from (mean +/- SEM) 0.10 +/- 0.01 TO 1.06 +/- 0.22 (p = 0.005) with the addition of beta 2-GPI. For IgA, 5 of 6 patients with SLE demonstrated a requirement of beta 2-GPI as a cofactor. Antibody binding increased from 0.27 +/- 0.05 to 1.77 +/- 0.35 (p = 0.003) with the addition of beta 2-GPI. CONCLUSION: beta 2-GPI is required as a cofactor for IgM and IgA aCL antibody binding.
OBJECTIVE: To determine the distribution of antibodies to cardiolipin (IgG, IgM and IgA) in a healthy population. To classify subjects according to a cutpoint in order to determine what level of antibody measurement would yield 95% specificity. METHODS: Antiphospholipid (aPL) antibodies were measured using a conventional ELISA technique, with isotype specific antibody, to determine levels of IgG, IgM and IgA binding to cardiolipin. The subjects were 282 Red Cross blood donors, 82 undergraduate medical and nursing students, and 13 laboratory volunteers. RESULTS: The distribution of aPL antibodies measured in units of optical density is significantly skewed, while the distribution of aPL antibodies measured on the log scale is nearly symmetric. Neither distribution is normally distributed. There was no evidence that aPL antibodies differed significantly by age (up to age 50) or sex. We estimate the 90th, 95th, and 99th percentiles for IgG, IgM and IgA antibodies for the optical densities and binding indices. CONCLUSION: For 95% specificity we conclude that an adjusted IgG optical density above 0.386, an adjusted IgM optical density above 0.301, or an adjusted IgA optical density above 0.085 be considered positive.
BACKGROUND: Burn injury is associated with increased muscle protein breakdown. However, the role of different intracellular proteolytic pathways in burn-induced muscle proteolysis is not known. STUDY DESIGN: A 30 percent total body surface area burn injury was inflicted on rats. Total and myofibrillar proteolysis was determined in incubated extensor digitorum longus muscles as release of tyrosine and 3-methylhistidine, respectively. Lysosomal proteolysis was assessed by using the lysosomotropic agents leupeptin and methylamine. Calcium-dependent proteolysis was determined by incubating muscles in the absence or presence of calcium or by blocking the calcium-dependent proteases calpain I and II. Energy-dependent proteolysis was determined in muscles depleted of adenosine triphosphate (ATP) by 2-deoxyglucose and 2,4-dinitrophenol. Muscle ubiquitin messenger RNA (mRNA) was determined by Northern blot analysis to assess ATP-ubiquitin-dependent proteolysis. RESULTS: Calcium-dependent total protein breakdown was stimulated in muscles from burned rats. However, the sensitivity to calcium in vitro was not increased after burn. The lysosomal and energy-dependent components of total protein breakdown were doubled in muscles from burned rats and the energy-dependent myofibrillar protein breakdown was increased almost seven-fold. Ubiquitin mRNA was increased in muscles from burned rats. CONCLUSIONS: Burn injury stimulates multiple proteolytic pathways in skeletal muscle. The ubiquitin-energy-dependent pathway may be particularly important for the breakdown of myofibrillar proteins.
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This paper describes the difference between wounds which heal by first and secondary intention. A brief overview of the stages of healing is then given: inflammation, granulation, epithelialisation and contraction plus the difficulties sometimes associated with the scarring of wounds. The properties of the ideal dressing for optimum wound healing rate are outlined, plus references to associated research. The litigation aspects of acute wound care in Accident and Emergency are covered, and then each dressing family is explored with indications given for appropriate application. Pain, infection, stab and gunshot wounds, plus the influence of factors delaying wound healing and the importance of patient education, are covered under separate headings. The importance of the nurse in planning and evaluating wound care is stressed.
Human immunodeficiency virus type 1 (HIV-1) infection is highly specific for its human host. In order to study HIV-1 infection of the human nervous system, we have established a small animal model in which second-trimester (11-17.5 weeks) human fetal brain or neural retina is transplanted into the anterior chamber of the eye of immunosuppressed adult rats (Epstein et al., 1992; Cvetkovich et al., 1992), and more recently in immunodeficient (SCID) mice. The human xenografts survive for many months, vascularize and form a blood-brain barrier. Immunohistochemistry with PGP 9.5 identified neuronal cell bodies and neuritic processes. Electron microscopy revealed axonal growth cones and synaptic junctions. Infection of these xenografts with cell-free HIV-1 proved difficult, however co-engraftment with HIV-1-infected human monocytes resulted in characteristic pathological changes, including the formation of syncytial giant cells, neuronal loss, and astroglial proliferation, supporting the hypothesis that these cells can mediate neurotoxicity. In other studies, xenografts of human fetal retinal tissue were readily infected with cell-free human cytomegalovirus (HCMV) strain AD169. These grafts contained cells with intracytoplasmic and intranuclear inclusions typical of HCMV infection. Productive infection within these grafts was demonstrated by the presence of immediate early, and late (capsid) HCMV antigens, by recovery of HCMV on human fibroblast cultures, and by serial passage of virus to additional retinal xenografts (DiLoreto et al., 1994).(ABSTRACT TRUNCATED AT 250 WORDS)
The data presented are the results from a prospective observational study which was conducted to investigate the effects of nutrition and other related factors on the outcome of pregnancy in nulliparous African American women 16-35 years old. Fasting blood samples were collected from the women during the first, second and third trimesters of pregnancy. At delivery, both maternal and cord samples were collected. Biochemical variables such as, serum folate, vitamin B12, ascorbic acid, vitamin E, ferritin, selected minerals as well as complete blood count (CBC) and red cell folate were analyzed in the blood samples. The concentrations of hematocrit, hemoglobin, white blood cells, red blood cells and vitamin B12 were below the reference non-pregnant ranges throughout gestation. Maternal concentrations of folate and vitamin E increased sequentially with increased gestational age. Serum ferritin, during the third trimester, declined to 58% of the first trimester concentration. Maternal levels of ferritin at delivery were one third of the values found in the infant (cord) sample. Cord levels of folate, ascorbic acid and vitamin B12 were higher than the concentrations in the maternal delivery samples. The data suggest that among this group of pregnant women, major physiological changes, such as plasma volume expansion which alters blood chemistry and maternal to fetal transfer of nutrients, were similar to the findings of other investigators. In this population however, the findings for serum and whole blood folate are contrary to those reported by other researchers, and the sequential increase in the maternal concentration of the vitamin during pregnancy could be attributed to the use of vitamin supplements.
Findings reported are for a subset of African American subjects, residing in the urban area of Washington, D. C., who participated in a Program Project designed to study nutrition, other factors, and the outcome of pregnancy. Fasting blood samples, drawn during each trimester of pregnancy and at delivery, were screened for concentrations of cocaine, phencyclidine (PCP) and marijuana. Since substance abusers are expected to consume inadequate diets, these samples were also analyzed for serum folate, vitamin B12, ferritin and ascorbic acid. Data for these biochemical variables were compared for subjects whose serum values for drugs were either above or below the drug screening threshold concentrations established by ADAMHA/NIDA. Pearson's correlations were used to determine relationships between pregnancy outcome variables and maternal serum drug concentrations. Blood samples drawn at delivery showed higher maternal: cord ratios (mean +/- SEM) for marijuana (3.3 +/- 2.2) and PCP (2.9 +/- 1.0) than for cocaine (1.0 +/- 0.2). The subjects whose serum values were above the ADAMHA/NIDA ranges for marijuana, PCP and cocaine had concentrations of folate and ferritin that were significantly less than those of subjects with lower serum drug levels (P < or = 0.05). High maternal serum concentrations of illicit drugs were accompanied by a significant increase in leukocyte count (P < or = 0.05). The level of maternal cocaine during the third trimester was inversely correlated with birthweight (r = -0.29; n = 52; P = 0.038) and head circumference (r = -0.28; n = 52; P = 0.047).(ABSTRACT TRUNCATED AT 250 WORDS)
We examined the relationship between the concentrations of blood lead and pregnancy outcomes in a subset of 349 African American women who enrolled in the program project, "Nutrition, Other Factors, and the Outcome of Pregnancy." Vitamin-mineral supplement users had significantly higher serum levels of ascorbic acid and vitamin E. Also, in supplement users, there were significantly lower mean concentrations of maternal blood lead. Inverse correlations were found between maternal levels of lead and the antioxidant vitamins, vitamin E and ascorbic acid. In addition, significant Pearson's correlations were observed between maternal blood lead levels and the following variables: positive correlations with calcium, phosphorus, mean corpuscular volume; inverse correlations with gestational age, Ponderal Index, infant orientation, and hematologic values. In the total subset, the three trimester sample means for maternal blood lead concentrations were not significantly different for mothers of infants who weighed less than 2500 g (low birth weight) and those who were delivered infants who weighed 2500 g or more. Clinically, nutrition may play a role in the reduction of potentially adverse effects from lead during pregnancy, i.e. protection of the fetus against lead toxicity and/or free radical damage through the antioxidant actions of vitamin E and ascorbic acid. Even when maternal blood lead levels are within the so-called "safe" range, maternal/use of a vitamin supplement supplying vitamin E and ascorbic acid during pregnancy may offer protection.
Muscle amino acid uptake is inhibited during sepsis and endotoxemia. Cytokines, in particular tumor necrosis factor (TNF) and interleukin-1 (IL-1), have been implicated as mediators of metabolic alterations in sepsis and other critical illness. In this study, we examined the effect of TNF and IL-1 on muscle amino acid uptake and tested the hypothesis that cytokine-induced changes in muscle amino acid uptake are mediated by glucocorticoids. Intraperitoneal injection in rats of 100 micrograms per kilogram body weight of human recombinant TNF alpha (rTNF alpha) or rIL-1 alpha resulted, two hours later, in 36 and 24 percent reduction, respectively, of amino acid transport in incubated soleus muscles, determined as intracellular uptake of alpha-aminoisobutyric acid. When rats were treated with the glucocorticoid receptor antagonist RU 38486 (5 milligrams per kilogram of body weight) two hours before cytokine injection, the inhibitory effect on muscle amino acid transport of TNF was blocked, whereas that of IL-1 was unaffected. The present results suggest that TNF and IL-1 may regulate amino acid transport in skeletal muscle and that the effect of TNF, but not that of IL-1, is at least partly mediated by glucocorticoids.
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The effects of different recombinant human cytokines and cytokine inhibitors were compared in a culture system in which cell contact with mutant EL-4 thymoma cells of murine origin efficiently stimulates human B cell proliferation and Ig secretion in conjunction with human T cell supernatant. IL-1 alpha, IL-1 beta, TNF-alpha, and IL-2 co-stimulated B cell proliferation and IgM, IgG, and IgA secretion, whereas IL-3, IL-4, IL-5, IL-6, IFN-gamma, or GM-CSF had weak or no activity in this regard. In contrast, TGF-beta 1 was strongly inhibitory. A very strict hierarchy of cytokine interactions was found in that IL-1 was necessary to induce TNF-alpha responsiveness, and TNF-alpha the IL-2 responsiveness, of the B cells. Most likely the small number of starting B cells in the present assay (300 FACS-separated B cells/200 microliters) minimized the effects of autocrine B cell factors. IL-4 together with IL-1 induced IgE secretion, and the IgE secretion was further increased by TNF-alpha. IFN-gamma had no modulatory effect on the IL-4 dependent IgE response in this system. Pretreatment of B cells with IL-1R antagonist (IL-1ra, which binds to IL-1R) or addition of soluble TNF receptor type 1 (sTNF-R55, which binds to TNF) completely inhibited the IL-1 or TNF-alpha effects, respectively. This occurred in a specific manner; the inhibition was reversed by a large excess of cytokine. IL-1ra also inhibited a B cell response induced by PMA-preactivated EL-4 cells alone. Because B cells responding to such preactivated EL-4 cells did not acquire TNF-alpha responsiveness, no IL-1 was apparently involved under this assay condition. It appears, therefore, 1) that IL-1ra can act on B cells and 2) that this antagonist may not only block IL-1R, but may provide a direct or indirect inhibitory signal interfering even with IL-1-independent B cell activation.
IgG was isolated from 9 patients with high levels of anticardiolipin antibodies (aCL). The standard ELISA was modified, using gelatin to postcoat ELISA plates and as diluent. Under these conditions, 8/9 samples of IgG bound to cardiolipin only in the presence of a cofactor, found in fetal calf serum and normal human serum (NHS). beta 2-glycoprotein I (apolipoprotein H) was at least as effective as NHS as a cofactor for 7/9 IgG samples. Our studies confirm that for some aCL detected in conventional assays, the antibody will react with cardiolipin only if beta 2-glycoprotein I is present.