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Biomedical subjects

N W Boyce

Publications and source records attributed to N W Boyce.

At least 19 recordsLinked to original sources
PubMed1997

Anti-neutrophil monoclonal antibody therapy inhibits the development of adjuvant arthritis.

The aim of this study was to determine the contribution of neutrophils to adjuvant arthritis (AA) by in vivo depletion of peripheral blood neutrophils. Specific anti-neutrophil MoAb, RP3 (10 mg), or a control antibody was given twice daily on days 8-11 after injection of Mycobacterium tuberculosis in inbred male Sprague-Dawley rats. RP3 treatment inhibited the neutrophil leukocytosis associated with AA (3.3 +/- 0.6 x 10(3)/mm3 versus 21.2 +/- 6.9 x 10(3)/mm3; P<0.001). On day 12, control animals exhibited severe arthritis as assessed by articular index (AI) (9.2 +/- 1.3), increase in paw volume (149.3 +/- 10.6%), and synovial fluid (SF) cell count (5.3 +/- 0.5 x 10(5)). RP3 treatment significantly reduced AI (1 +/- 0.1; P<0.001), paw volume (103.6 +/- 5.8%; P<0.001) and SF cells (0.6 +/- 0.1 x 10(5); P<0.001) without affecting cutaneous DTH (treated 0.6 +/- 0.1 mm change in thickness, control 0.8 +/- 0.2 mm; NS). Additional experiments demonstrated that CD4+ cell depletion but not decomplementation inhibited AA development and synovial neutrophil accumulation. Depletion of circulating neutrophils prevented joint inflammation and synovial leucocyte influx in AA, suggesting a pivotal role for neutrophils in the effector phase of AA. Inhibition of neutrophil accumulation by CD4+ cell depletion and not by decomplementation suggests that neutrophil accumulation in AA is T cell-dependent.

Animals↗
PubMed1995

Detection of intracellular lipocortin 1 in human leukocyte subsets.

Lipocortin 1, a putative mediator of the anti-inflammatory actions of glucocorticoids, is present intracellularly in a variety of tissues including human peripheral blood leukocytes. We investigated the presence of lipocortin 1 in human leukocyte subsets using permeabilization flow cytometry. Constitutive lipocortin 1 was detected in U937 myelomonocytic leukemia cells, and lipocortin 1 was increased by treatment with PMA or PMA+IFN-gamma (P < 0.05) but not by dexamethasone. Lipocortin 1 was present in all leukocyte subsets except B lymphocytes (CD19/20+, P < 0.001). Lipocortin 1 content was maximal in monocytes and polymorphonuclear neutrophils and least in lymphocytes (P < 0.001). Monocyte lipocortin 1 was strongly associated with surface expression of CD14 and HLA-DR. Among non-B lymphocytes, a range of lipocortin 1 fluorescence was observed. Lipocortin 1 fluorescence was greatest in natural killer cells (CD56+, P < 0.001) and CD57+ cells, but T cell subset markers did not otherwise discriminate variations in lipocortin 1. Induction of lymphocyte proliferation by PHA, anti-CD3, Con A, superantigen, and SAC was not associated with significant shifts in lipocortin 1 content. Dexamethasone (10(-10)-10(-6) M) did not induce increases in PB leukocyte lipocortin 1. We conclude that lipocortin 1 content in human leukocytes varies significantly among phenotypic subsets. This has significance for the investigation of inflammatory disease where certain cell types predominate.

Annexin A1↗
PubMed1993

Vasculitis--an overview.

The systemic vasculitides are a diverse group of conditions surrounded by a degree of mythology. Much of the apparent complexity of these disorders is due to application of illogical and rigid classification schemes. This overview has focused on the need to understand the terminology used to describe the vasculitides and their presenting clinical syndromes. The important role of the detection of autoantibodies to neutrophil cytoplasmic antigens (ANCA) in the diagnostic assessment of patients suspected of having a systemic vasculitis has been highlighted. Finally, the replacement of the dogmatic application of purportedly 'disease-specific' therapeutic protocols with a balanced assessment of the risk-benefit ratio of therapeutic strategies in an individual patient has been encouraged.

Female↗
PubMed1992

Adverse reaction to a Chinese herbal remedy.

OBJECTIVE: To report a multisystem illness in a patient after ingestion of Chinese herbal medicines, together with an analysis of the herbal medicine and to alert physicians to the growing clinical importance of adverse reactions to herbal remedies. CLINICAL FEATURES: A 61-year-old Chinese Vietnamese man with a history of atrial fibrillation and left cerebral hemisphere infarction three months previously presented after a three-day illness with acute hepatorenal failure, multiple pulmonary emboli, peripheral arterial thromboembolism and laboratory features of consumptive coagulopathy. For three days before presentation, he drank a daily infusion of herbal medicine. INTERVENTION: Intensive supportive medical care including haemodiafiltration resulted in recovery of renal function, liver function and return of coagulation parameters to normal over a one-month period. Toxicological analysis of an infusion prepared from a sample of the patient's herbal medicine revealed the potentially toxic compounds benzaldehyde, cinnamoyl alcohol and ephedrine. CONCLUSION: The ingestion of herbal medicine caused or contributed to the patient's illness.

Chemical and Drug Induced Liver Injury↗
PubMed1991

Acute pulmonary and renal injury after administration of heterologous anti-lung antibodies in the rat. Characterization of ultrastructural binding sites, basement membrane epitopes, and inflammatory mediation systems.

Male Sprague-Dawley rats developed acute lung and renal injury after administration of heterologous anti-lung antibody. Both organs demonstrated an increase in protein permeability after antibody binding to basement membrane (BM) antigens (lung permeability index 0.342 +/- 0.009 versus control 0.214 +/- 0.011: p less than 0.05. Urinary protein excretion 5.112 +/- 0.899 mg/hour versus control 0.402 +/- 0.008 mg/hour: p less than 0.01). The threshold value for the development of lung injury was 27.2 +/- 4.8 micrograms of antibody globulin/g of tissue (micrograms/gm). Immunoblot analysis probing with the anti-lung antibody revealed at least one common antigenic determinant (82 to 84 kilodaltons) bound within collagenase-solubilized pulmonary and glomerular BMs. Increasing doses of antibody produced hemorrhagic pneumonitis and diffuse alveolar damage. Immunofluorescence microscopy confirmed linear alveolar and glomerular BM antibody binding. Immunogold electron microscopy allowed precise identification, in intense linear patterns, of BM binding sites within lung and glomeruli. Functional lung injury was prevented by either leukocyte-depletion or complement-depletion (lung permeability index antibody-treated, complement-depleted 0.235 +/- 0.034: both p greater than 0.05 compared with controls). Injury mediation in this acute humoral model of lung damage is both complement- and leukocyte-dependent, as previously described for the renal component of heterologous anti-glomerular BM antibody-induced inflammatory disease.

Animals↗
PubMed1989

Immunoregulation through CD8 (Ly-2): state of aggregation with the alpha/beta/CD3 T cell receptor controls interleukin 2-dependent T cell growth.

The activation of T lymphocytes by an antigenic challenge requires that the CD3 T cell receptor alpha/beta (TcR) is bound to an appropriate ligand, i.e. major histocompatibility complex antigen, on an antigen-presenting cell. In addition, numerous studies suggest that the accessory molecules CD4 and CD8 participate in the recognition process, and may have inhibitory as well as augmenting effects depending on the ways in which they participate. In the present study we attempt to define the conditions by which CD8 exerts enhancing and inhibitory effects on resting CD8+ T cell activation, and which parameters of activation are regulated through participation of CD8/CD4. We find that experimental procedures leading to TcR-CD8 aggregation induce T cell activation whereas experimental procedures preventing TcR-CD8 aggregation inhibit T cell activation. CD8/CD4-induced variations in the extent of T cell activation are apparent as variations in interleukin 2 (IL 2)-dependent growth and in the number of blastoid cells bearing IL 2 receptors. Inhibition of CD8+ T cell activation is successful only if the majority, if not all CD8 molecules are occupied by soluble antibody. This latter finding argues against the suggestion of other groups that CD8 may be a receptor for negative signaling. Rather, the results support the alternative notion that a basal level of TcR-CD8 aggregation, existing in the resting state or induced by TcR-ligand interaction, is an essential prerequisite for CD8+ T cell activation. Enhancement or depression of this basal level of aggregation causes facilitation or inhibition, respectively, of activation. This may be a mechanism for the regulation of IL 2-dependent clonal expansion of T cells in immune responses.

Adjuvants, Immunologic↗
PubMed1989

Macrophage-Fc-receptor affinity: role in cellular mediation of antibody initiated glomerulonephritis.

The role of immunoglobulin (Ig) Fc-macrophage cell surface receptor affinity (macrophage Fc-affinity) in determining the mediation systems responsible for immune glomerular injury has been studied. Glomerular injury was initiated in rabbits by the passive administration of immunoglobulin preparations directed against a "planted" glomerular antigen. The mediation systems inducing injury initiated by antibody pools of high and low macrophage Fc-affinity were compared. In this model of glomerulonephritis macrophage Fc-affinity was the only variable. IgFc-macrophage affinity was quantitated in fluid-phase and solid-phase assay systems (high affinity pool KA = 7.05 +/- 1.11 x 10(5) L/M; low affinity pool KA = 0.79 +/- 0.13 x 10(5) L/M). Comparative antibody binding studies demonstrated that renal injury occurred with high affinity antibody at kidney-fixed-antibody (KFA) binding levels significantly below the KFA levels required for glomerular injury with administration of low affinity antibody [KFA's: 25.1 +/- 2.1 micrograms antibody globulin/g kidney cortex (micrograms/g) and 60.5 +/- 2.4 micrograms/g, respectively, P less than 0.01]. Furthermore, antibody with high macrophage Fc-receptor affinity induced a macrophage-mediated, complement-independent glomerular injury while antibody with low macrophage Fc-receptor affinity induced renal injury via complement and neutrophil dependent mechanisms. IgFc-receptor affinity determined the degree of macrophage recruitment into glomeruli via immune adherence mechanisms, and therefore is an important determinant of which inflammatory mediator system is ultimately responsible for antibody-initiated glomerular injury.

Animals↗
PubMed1989

Glomerular macrophages produce reactive oxygen species in experimental glomerulonephritis.

The production of reactive oxygen species by intraglomerular macrophages was assessed in a macrophage dependent model of diffuse proliferative glomerulonephritis in rabbits. Glomerular macrophages were obtained from isolated nephritic glomeruli by short term (60 min) culture. Control macrophage populations were simultaneously obtained from peripheral blood (blood monocytes) and lung lavage fluid (alveolar macrophages). Superoxide anion (O2-), hydrogen peroxide (H2O2) and hydroxyl radical (OH.) production was assessed. Glomerular macrophage production of O2- (48.9 +/- 5.5 nmol/hr/10(6) cells), H2O2 (4.4 +/- 2.5 nmol/hr/10(6) cells) and OH. (57.8 +/- 4.7 U/hr/10(6) cells) was significantly greater than the production of reactive oxygen species seen with control monocyte populations: alveolar macrophages, O2- 9.8 +/- 2.0 nmol/hr/10(6) cells; H2O2 0.6 +/- 0.3 nmol/hr/10(6) cells; OH. 11.0 +/- 1.8 U/hr/10(6) cells; blood monocytes, O2- 8.6 +/- 1.4 nmol/hr/10(6) cells; OH. 9.9 +/- 1.2 U/hr/10(6) cells, (all P less than 0.05 cf. glom macs). Hydrogen peroxide production by blood monocytes (1.6 +/- 0.9 nmol/hr/10(6) cells) was less than glomerular macrophages, however this difference was not statistically significant. The enhanced production of reactive oxygen species by glomerular macrophages in this macrophage dependent model of glomerulonephritis suggests that these mononuclear cells are locally activated within the glomerulus following recruitment from the circulation. Reactive oxygen species production by glomerular macrophages may contribute to their ability to induce glomerular basement membrane injury in this disease.

Animals↗
PubMed1989

Granulocyte independence of pulmonary oxygen toxicity in the rat.

The role of neutrophils in the mediation of severe normobaric hyperoxic lung injury has been studied by monitoring the effects of neutrophil depletion on a rat model of pulmonary oxygen toxicity. Pulmonary capillary permeability, assessed using an [125I]albumin lung permeability index (LPI), progressively increased with an increased duration of hyperoxia exposure in normal animals (LPI = 0.43 +/- 0.09 at 24 h; 0.95 +/- 0.17 at 48 h; 1.56 +/- 0.21 at 60 h), despite the absence of any significant tissue or bronchoalveolar lavage evidence of neutrophil infiltration until 60 h of hyperoxia exposure. Neutrophil depletion (using cyclophosphamide) blocked this late neutrophil infiltrate but failed to attenuate lung injury (LPI = 0.38 +/- 0.06 at 24 h; 0.89 +/- 0.16 at 48 h; 1.58 +/- 0.10 at 60 h; all p greater than .05 compared with leucocyte-replete/normal animals exposed to hyperoxia). The temporal dissociation of pulmonary neutrophil accumulation and pulmonary injury and the failure of effective neutrophil depletion to abrogate hyperoxic lung injury indicate that neutrophil polymorphs play no substantive role in the mediation of tissue injury in this model of severe pulmonary oxygen toxicity.

Animals↗
PubMed1989

Relative contributions of chemo-attractant and terminal components of complement to anti-glomerular basement membrane (GBM) glomerulonephritis.

The relative contributions of chemo-attractant and terminal components of complement to heterologous phase glomerular injury was studied in anti-GBM glomerulonephritis in rabbits. Normal rabbits (complement intact) were given anti-GBM antibody at a dose which resulted in 140 micrograms specific kidney-fixed antibody per gram of renal cortex, and developed significant proteinuria (1910 +/- 327 mg/24 h; control 18.2 +/- 6.1 mg/24 h; P less than 0.01). Leucocyte depletion significantly reduced but did not abolish proteinuria (574 +/- 186 mg/24 h, P less than 0.05). Complement depletion of neutrophil-depleted rabbits resulted in a further significant reduction in proteinuria 50.1 +/- 12.2 mg/24 h, P less than 0.05; versus neutrophil-depleted, complement-intact rabbits), indicating that both neutrophil accumulation and complement activation independent of neutrophils contribute to injury in this model. Rabbits congenitally deficient in the sixth component of complement (C6D) developed similar levels of proteinuria (2099 +/- 796 mg/24 h) to normal rabbits given an identical dose of antibody. However, after leucocyte depletion, C6D rabbits developed significantly less proteinuria (135 +/- 56 mg/24 h) than did leucocyte-depleted, complement-intact rabbits (P less than 0.05). These studies show that terminal complement components are not necessary for the full expression of acute anti-GBM antibody-initiated injury in leucocyte-intact rabbits. However, in the absence of leucocytes, C6 and the terminal complement components are apparently responsible for the majority of the complement-dependent glomerular injury.

Animals↗
PubMed1989

Localization of antiglomerular basement membrane-binding polyclonal antibodies in rat lung and kidney using post-embedding immunogold electron microscopy.

Post-embedding immunogold electron microscopy (IAuEM) techniques utilizing low-temperature embedding in Lowicryl K4m and LR White resin were used to localize the binding sites of two sheep anti-rat glomerular basement membrane polyclonal antibodies (P1 and P2) and a sheep anti-rat lung antigen antibody. P1 localization was bilaminar in a linear pattern along the subepithelial and particularly the subendothelial aspect of the glomerular basement membrane. P2 was bound diffusely throughout the lamina densa, even at supramaximal doses. The anti-lung antibody bound in an interrupted linear pattern throughout the lung basement membrane (alveolar and capillary), and showed an intense, diffuse binding to the glomerular basement membrane. IAuEM allowed definition of the precise basement membrane binding sites of these polyclonal reagents.

Animals↗
PubMed1988

Heterologous cross-linking of Lyt-2 (CD8) to the alpha beta-T cell receptor is more effective in T cell activation than homologous alpha beta-T cell receptor cross-linking.

Ag recognition of Lyt-2 (CD8)-positive T lymphocytes requires the presentation by APC of a suitably processed Ag in association with MHC class I molecules. In previous studies we have obtained evidence that, for optimal activation, both the alpha beta-TCR and Lyt-2 have to participate in this recognition process. In the current study we investigate the functional consequences of limited cross-linking of these cell surface molecules by using soluble, dimeric hetero- and homoconjugates of mAb to Lyt-2 and to the TCR beta-chain (F23.1). Heterologous cross-linking of Lyt-2 to the TCR induced a vigorous, selective Lyt-2+ T cell proliferative response. Functionally active cytotoxic cells were generated, and a high frequency of responding cells was observed in limiting dilution analyses. In contrast, homologous TCR cross-linking initiated a less pronounced proliferation with a relatively low frequency of response, whereas Lyt-2 cross-linking resulted in no cellular proliferation. Significant T cell activation occurred with exposure to anti-Lyt-2: F23.1 mAb dimers at concentrations an order of magnitude lower than those required for stimulation by F23.1:F23.1 mAb dimers. The induction of proliferation by mAb dimers occurred in the absence of Fc components and in rigorously APC depleted, purified T cell preparations. Effective stimulation of resting T cells could be induced also by heterodimers of monovalent Fab fragments. Heterologous cross-linking of Lyt-2 to the TCR was superior to homologous TCR cross-linking primarily with respect to proliferation in IL-2 containing media and to IL-2R expression, whereas proliferation in response to other lymphokines and the production of IL-2 itself were similar under both cross-linking regimens. Thus, when linked to the TCR, Lyt-2 contributed a strong, positive signal toward IL-2-dependent growth of resting T cells. We assume that in the case of Ag-driven T cell activation, the class I MHC molecule acts as the physiologic cross-linking ligand for Lyt-2 and the TCR.

Animals↗
PubMed1988

Nonhepatitis B-associated liver disease in a renal transplant population.

The spectrum of liver disease in a population of 293 patients receiving 353 renal transplants (1971-1984) was reviewed. This study looked retrospectively at the histological features of liver disease in this population, and prospectively at the clinical and biochemical features of liver disease associated with renal transplantation. In all patients, infection with hepatitis B was excluded. Six deaths, primarily attributable to hepatic failure have occurred: one, acute herpes simplex infection; one, subacute massive hepatic necrosis of uncertain etiology; two, pretransplant liver disease; and two, posttransplantation cirrhosis of uncertain etiology. Review of the hepatic histology of 26 patients with known liver disease following transplantation revealed a wide range of pathologies with few specific correlations with their clinical status or biochemical tests of liver function. The prevalence of hepatic dysfunction following transplantation in our patient population was assessed by prospective biochemical screening of 111 transplant recipients over a 6-month interval. During this time period, 27 patients (24%) displayed biochemical evidence of hepatic dysfunction. Liver disease was known to have predated transplantation in only three of 27. Episodes of abnormal liver function occasionally occurred during an identifiable acute illness (six of 27), although the majority (21 of 27) had chronic hepatic dysfunction. Transplant recipients with abnormal liver function could not be differentiated from a cohort with normal liver function on the basis of age, sex, duration of graft function, or alcohol/drug intake. The possible etiologies of nonhepatitis B liver dysfunction following renal transplantation are discussed, and the high prevalence of biochemical evidence of hepatic dysfunction in this population free of hepatitis B infection is emphasized.

Adult↗
PubMed1988

Intraperitoneal (IP) vancomycin therapy for CAPD peritonitis--a prospective, randomized comparison of intermittent v continuous therapy.

The use of intraperitoneal (IP) vancomycin as initial, single agent therapy for gram positive and "no organism" continuous ambulatory peritoneal dialysis (CAPD) peritonitis is described, comparing continuous and intermittent administration schedules. "Continuous" therapy consisted of an IP 1-g loading dose of vancomycin followed by 30 mg/L dialysate effluent. "Intermittent" therapy consisted of 2 IP doses of 30 mg vancomycin/kg body weight--the initial dose delivered at diagnosis and the second dose 1 week later. All patients presenting with peritonitis (n = 90) were randomized to receive either continuous or intermittent vancomycin therapy. Patients in whom gram negative organisms and fungi were identified by microscopy and culture were transferred to therapy with a more appropriate antibiotic (n = 39). In the remainder (n = 51), CAPD peritonitis was treated solely with vancomycin (continuous, n = 21; intermittent, n = 30). Clinical resolution was seen in all patients, requiring a mean of 3.2 days for macroscopic clearing of dialysate effluent. Recurrence of peritonitis within 1 month of cessation of therapy was unusual and did not vary between treatment protocols (4/21 v 3/30; P = NS). There were no differences in observed side effects. Thus, IP vancomycin proved to be a useful single agent therapy for gram positive and no organism CAPD peritonitis. Therapy with two IP doses was effective and as safe as continuous IP vancomycin therapy, and therefore should replace other vancomycin administration schedules in the treatment of CAPD peritonitis.

Drug Administration Schedule↗
PubMed1988

Cytomegalovirus infection complicating renal transplantation and its relationship to acute transplant glomerulopathy.

The incidence of cytomegalovirus (CMV) infection was established, using laboratory criteria, in 298 patients receiving 362 renal allografts (164/298 = 55%). The incidence of CMV infection did not differ between azathioprine/prednisolone-treated and cyclosporine-treated patients (55% vs. 57% NS). The use of antithymocyte globulin (ATG) increased the incidence of CMV infection (78% vs. 51%: P less than 0.01). Donor and recipient CMV status, known for 116 allografts, did not correlate with the incidence of CMV infection (recipient CMV-positive = 50%; recipient CMV-negative = 54%: NS). CMV infection was responsible for 8 patients' deaths (2.7% mortality). Thirty-three patients with acute transplant glomerulopathy were identified (11%). There was no correlation between acute transplant glomerulopathy and CMV infection. Glomerulopathy was associated with poor graft survival (22/33 patients with a graft survival of less than 6 months). Thus CMV infection, although a common complication of renal transplantation with significant morbidity and mortality, is not closely associated with acute transplant glomerulopathy. Further, the lack of correlation of donor-recipient CMV serologic status with graft outcome limits the usefulness of pretransplantation donor screening.

Acute Disease↗
PubMed1988

Tubular antigen-associated renal disease in New Zealand white rabbits. II. Investigation of mediators of glomerular injury: localization and characterization of the glomerular capillary wall antigen.

Mediation of the glomerular lesion and proteinuria produced by sheep antirabbit F x 1A globulin (SAFG) in rabbits was examined by prior treatment with cobra venom factor and nitrogen mustard. SAFG binding and proteinuria at 24 h were independent of complement or leucocytes but dose dependent. SAFG reacted by immunoblot with a wide range of antigens in deoxycholate extracts of rabbit glomeruli and autologous F x 1A including eight prominent shared bands of 29-128 kd. Immunogold electron microscopy has revealed the in vivo glomerular binding of SAFG as discrete, nonlinear and predominantly within the laminae rarae, in association with epithelial and particularly endothelial components of the glomerular capillary wall. In vitro binding was prominent on the endothelium. Proteinuria in this model is mediated by antibody without requirement for complement or leucocytes. The putative antigen(s) is/are associated with components of the glomerular capillary wall which share epitopes with autologous tubular F x 1A. This model is an example of an in situ immune complex glomerular nephritis and is distinct from the classical anti-F x 1A model, passive Heymann's nephritis in the rat.

Animals↗