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K Mosley

Publications and source records attributed to K Mosley.

17 recordsLinked to original sources
PubMed2006

Urinary proteomic profiles distinguish between active and inactive lupus nephritis.

OBJECTIVES: Key aims of the treatment of lupus nephritis (LN) are to induce and maintain remission with minimal side effects. However, assessing ongoing renal inflammatory activity is poorly served by current diagnostic tests apart from renal biopsy, but frequent biopsies cannot be justified. Our long-term aim is to identify novel biomarkers from urinary protein profiles to improve diagnosis and monitoring of activity and response to therapy in LN. METHODS: We used surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) to identify biomarkers able to discriminate between urine samples from patients with inactive (n= 49) and active (n= 26) LN. Discriminant function analysis was used to define the minimum number of proteins whose levels best distinguished between the two patient groups. Serial urines of six biopsied patients were studied prospectively, and multiple regression (MR) scores calculated. RESULTS: Proteins with masses of 3340 and 3980 distinguished active from inactive LN with 92% sensitivity and specificity of 92% each. The prospective study of the biopsied patients demonstrated that MR scores could predict both relapse and remission earlier than traditional clinical markers. CONCLUSIONS: SELDI-TOF MS identified potential biomarker profiles strongly associated with activity in LN. Identification of these proteins will allow us to devise specific assays to routinely monitor disease progression, and alter immunosuppressive drug regimens accordingly. These proteins may also play a critical role in the pathogenesis of glomerulonephritis, and could therefore provide targets for therapeutic intervention.

Adult↗
PubMed2000

Mesangial cell necrosis in Thy 1 glomerulonephritis--an ultrastructural study.

Cell death is central to many physiological and pathological processes. As tissue reactions to the two forms of cell death, necrosis and apoptosis, differ, it is critical to distinguish between them. Although ultrastructure is still the definitive means of assessing this, there are very few in vivo studies. Administration of anti-Thy 1 antibody in rats is a model of acute glomerular mesangial cell death due to their expression of the Thy 1.1 epitope. The nature of this process is unclear; apoptosis was suggested from early morphological studies and recent in vitro effects of anti-Thy 1.1 antibody. We have re-examined the changes by electron microscopy, and identified a process of cell necrosis starting within 30 min of anti-Thy 1.1 antibody administration. Although there was chromatin condensation, the necrotic features distinctive from apoptosis were: loss of nuclear membranes, cell swelling and degeneration of cytoplasmic organelles, with liberation of chromatin and organelles into the interstitium causing acute inflammation without phagocytic uptake of apoptotic bodies. These findings accord with the known complement dependence of this model. Ultrastructure is a valuable means of differentiating between in vivo necrosis and apoptosis and this is important for understanding the pathogenesis of injury and subsequent tissue responses.

Animals↗
PubMed1999

Induced nitric oxide (NO) synthesis in heterologous nephrotoxic nephritis; effects of selective inhibition in neutrophil-dependent glomerulonephritis.

Increased NO synthesis, due to inducible NO synthase (iNOS) activity, is found in macrophage-associated glomerulonephritis. Little is known about NO in neutrophil-dependent immune complex inflammation, and its role remains controversial. We therefore studied early phase heterologous nephrotoxic nephritis (HNTN) induced in rats by nephrotoxic globulin and the effects of selective iNOS inhibition of this model. At 2 h of the model iNOS mRNA was induced and nitrite (NO-2) was generated in glomeruli incubated ex vivo (5.2 +/- 1.0 nmol/2000 glomeruli per 24 h). There were 14.7 +/- 2.2 polymorphonuclear neutrophils (PMN)/glomerulus (normal controls 0.1 +/- 0.1). At 8 h urinary protein was 69 +/- 15.3 (normal controls 0. 6 +/- 0.2 mg/24 h). Peritoneal PMN expressed iNOS and produced significant NO-2 (basal 11.2 +/- 0.3 nmol/106 cells per 24 h). Selective iNOS inhibition with L-N6-(1-iminoethyl)-lysine (L-NIL) in vitro inhibited nephritic glomerular and PMN NO-2 synthesis. In HNTN L-NIL in vivo significantly suppressed elevated plasma NO-2/NO-3 levels (representative experiment: 17 +/- 2 microM, untreated 40 +/- 4 microM, P = < 0.01, normal control 18 +/- 2 microM). This inhibition did not affect leucocyte infiltration into glomeruli or induce thrombosis. There was no consistent effect on proteinuria. This is the first demonstration of glomerular iNOS induction and high output NO production in the acute phase of PMN-dependent acute immune complex glomerulonephritis. Selective iNOS inhibition does not affect the primary mechanism of injury (leucocyte infiltration) in this model.

Animals↗
PubMed1998

Arginase AI is upregulated in acute immune complex-induced inflammation.

Previous studies have shown high arginase activity at inflammatory sites. Arginase converts L-arginine to L-ornithine, sharing a common substrate with nitric oxide synthase. It exists as two isoforms, AI and AII. While the function of liver arginase (AI) in ureagenesis has been defined, the role and isoform of arginase in cells without a complete urea cycle are unknown. We therefore determined arginase isoform mRNA expression in glomerular acute immune complex inflammation, and its cultured constituent cells. AI was induced in nephritic glomeruli, and in mesangial cells stimulated with IL-4 and cAMP, and was present in elicited neutrophils and macrophages. AII was constitutively expressed. Our data strongly suggest that AI, thought to be restricted to the liver, accounts for high arginase activity at inflammatory sites where it may limit high output nitric oxide production and generate polyamines and proline essential for cell proliferation and matrix production. This identification of AI in inflamed tissue is an important step for understanding the consequences of increased arginase activity.

Acute Disease↗
PubMed1998

Heme oxygenase is induced in nephrotoxic nephritis and hemin, a stimulator of heme oxygenase synthesis, ameliorates disease.

Heme oxygenase (HO) catalyses degradation of heme to biliverdin, iron and carbon monoxide (CO). Two isoforms exist, a constitutive form and an inducible form (HO-1). Induction of HO-1 may have protective effects in inflammation. We studied heterologous (HNTN) and accelerated (ANTN) nephrotoxic nephritis in Lewis rats. Hemin, an inducer of HO-1, (30 mumol/kg) was administered 18 hours before induction of nephritis and 72 hours later in ANTN. HO-1 was not detected immunohistochemically in normal glomeruli but was present in HNTN and ANTN in cells with the morphology of macrophages. HO-1 induction was confirmed by RT-PCR. In normal rats hemin induced glomerular HO-1 mRNA at 18 hours. In HNTN hemin markedly reduced proteinuria at 24 hours (10 +/- 4 mg/24 hr; control 54 +/- 16; P < 0.05), neutrophil infiltration at two hours (29.8 +/- 1.8 vs. 22.3 +/- 1.5 neutrophils/glomerulus, P < 0.05), and glomerular macrophage number at two hours (2.1 +/- 0.1 vs. 3.1 +/- 0.4 cells/glomerulus, P < 0.05). In ANTN proteinuria was reduced at day 1 and day 4 (36 +/- 11 vs. 60 +/- 15 and 36 +/- 7 vs. 86 +/- 9 mg protein/24 hr, respectively, P < 0.001), glomerular thrombi were reduced by hemin at day 1 and 4 (1.5 +/- 2.7 vs. 2.7 +/- 0.2 and 1.3 +/- 0.01 vs. 2.9 +/- 0.02, respectively, P < 0.001) and glomerular macrophage infiltration was reduced on day 4 (11.2 +/- 0.8 cells/glom; control 15.9 +/- 0.8, P < 0.01). Possible mechanisms by which HO-1 ameliorates disease include anti-complement or anti-oxidant effects of bilirubin and vasodilator and anti-platelet effects of carbon monoxide.

Animals↗
PubMed1997

Combination chemotherapy with cyclophosphamide, vincristine, adriamycin, and dexamethasone (CVAD) plus oral quinine and verapamil in patients with advanced breast cancer.

We evaluated the question of whether the chemosensitizers verapamil and quinine given orally to breast cancer patients failing combination chemotherapy alone would result in additional clinical responses. In vitro studies reported here showed verapamil sensitization of Adriamycin resistance in 18.8% of fresh human breast cancer specimens tested. Patients (27) were first treated with cyclophosphamide, vincristine, Adriamycin and dexamethasone (CVAD) alone. Verapamil and quinine were added in patients with tumors failing to respond or progressing on CVAD alone. Following treatment with CVAD alone there were no complete remissions and 3 patients (11%) developed partial remissions lasting 5.5, 8, 10.5 months. With the addition of verapamil and quinine to the CVAD regimen, one patient (4%) developed a complete remission of 11.8 months duration and 4 additional patients (15%) developed partial remissions lasting 2.8, 17.3, 19 and > 40 months. Thus, the overall rate of CVAD sensitization by verapamil and quinine was 19%. Treatment with CVAD plus verapamil and quinine was generally well tolerated with observed toxicities including: myelosuppression, neuropathy, Cushingoid symptoms and tinnitus and/or dizziness due to quinine. We conclude that addition of the non-cytotoxic chemosensitizers verapamil and quinine to CVAD in patients failing CVAD alone results in additional clinical responses in a small percentage of patients, some with long term durations. The results of this study lend credence to the notion that non-cytotoxic chemosensitizers can enhance the clinical activity of combination chemotherapy and the search for more effective and less toxic chemosensitizers continues.

Adult↗
PubMed1996

Receptor-mediated phagocytosis of myelin by macrophages and microglia: effect of opsonization and receptor blocking agents.

Myelin is phagocytosed by microglia (MG) and to a somewhat lesser extent by peritoneal macrophages (M phi) in a dose- and time-dependent manner. In serum-free medium opsonization of rat myelin significantly enhances binding and ingestion, more by rat macrophages than by microglia. Furthermore the requirement for opsonization is not restricted to anti-myelin antibodies as the difference in the rate of myelin uptake by macrophages is largely eliminated when they are cultured in 10% fetal calf serum. Binding and ingestion of both myelin and opsonized myelin are inhibited to the same dose-dependent extent by zymosan, oxidized LDL, peroxidase-antiperoxidase (PAP), opsonized erythrocytes and the anti-CR3 antibody OX42 implicating lectin, scavenger, Fc and complement receptors in the phagocytosis of myelin. Thus while the differential uptake of myelin and opsonized myelin by macrophages would indicate a central role for the Fc receptor, binding inhibition studies implicate a range of membrane receptors which would obviate the need for antigen-antibody complexing to stimulate phagocytosis. Uptake of both myelin preparations by macrophages or microglia is stimulated by interferon-gamma and inhibited by TGF-beta, and the process of ingestion results in increased nitric oxide release and decreased superoxide production, the effect being more pronounced when myelin is opsonized.

Animals↗
PubMed1993

Peripheral endotoxin induces hypothalamic immunoreactive interleukin-1 beta in the rat.

Interleukin-1 (IL-1) is a polypeptide produced by a variety of cells and contributes to the general host response to inflammation. It displays a wide spectrum of inflammatory, metabolic, physiological, haematopoietic and immunological activities. Brain cells, including neurones, microglia, endothelial cells and astrocytes can all produce IL-1 beta in response to various physiological and pathological stimuli. In this report we show that peripherally administered endotoxin stimulates the appearance of immunoreactive IL-1 beta (IL-1 beta) in the rat hypothalamus as measured by an ultrasensitive, highly specific enzyme amplified immunometric assay for rat IL-1 beta.

Animals↗
PubMed1991

Systemic toxic effects associated with high-dose verapamil infusion and chemotherapy administration.

Aside from its more conventional uses as a cardiovascular drug, the calcium channel blocker verapamil has recently been added to chemotherapeutic regimens to reduce drug resistance in B-cell and other neoplasms that express the P-glycoprotein. We recently treated patients with continuous-infusion verapamil (0.15 mg/kg per hour to 0.60 mg/kg per hour) over a 5-day period in combination with continuous-infusion vincristine and doxorubicin plus oral dexamethasone. Seventy-one courses involving 35 hospitalized patients were prospectively studied for cardiovascular and other side effects. Cardiovascular side effects were observed most frequently and consisted of first-degree heart block, hypotension, sinus bradycardia, and junctional rhythms. We observed higher degree heart block, but the QRS interval remained narrow and the ventricular escape rate remained relatively normal. Effects on mean arterial pressure, heart rate, and PR interval were both time and dose related. Severe, symptomatic congestive heart failure was rarely observed. The most common noncardiovascular side effects were constipation, peripheral edema, and weight gain. All systemic toxic effects observed were easily treated or disappeared with either temporary or permanent discontinuation of the verapamil infusion or by a decrease in the dose of verapamil. We conclude that the cardiovascular side effects associated with continuous, high-dose intravenous verapamil therapy are significant and dose limiting but are rapidly reversible. Less cardiotoxic chemosensitizers are needed to reverse multidrug resistance in cancer.

Adult↗
PubMed1991

Interleukin-1 beta production in vivo and in vitro in rats and mice measured using specific immunoradiometric assays.

Activated cells of the monocyte-macrophage lineage produce two forms of the inflammatory cytokine interleukin-1 (IL-1), IL-1 alpha and IL-1 beta, of which IL-1 beta is the predominant secreted form and has a wide range of modulatory effects on the endocrine system. Immunoassays of human IL-1 beta have been described, but are not suitable for measurement of rat and mouse IL-1 beta because of limited cross-reactivity. Polyclonal sheep anti-rat or sheep anti-mouse IL-1 beta antisera were used to develop sensitive and specific immunoradiometric assays for rat and mouse IL-1 beta. Secretion of IL-1 beta from endotoxin-activated monocytes or macrophages was measured in vitro or in vivo in both species. In vitro, rat monocytes and mouse macrophages produced IL-1 beta in response to endotoxin, with a relatively small proportion of total IL-1 beta being secreted. In vivo, endotoxin stimulated an increase in plasma IL-1 beta in both animals. The development of these assays will facilitate studies of the role of endogenous IL-1 beta in animal endocrine models.

Animals↗
PubMed1989

Effect of dipyridamole on fluorodeoxyuridine cytotoxicity in vitro and in cancer patients.

Dipyridamole (DP) has previously been studied both in vitro and in vivo in combination with various anti-metabolites, including methotrexate and 5-fluorouracil (5FU). We evaluated in vitro and clinically the effects of adding DP to fluorodeoxyuridine (FUDR) in colorectal cancer. Using a human colony-forming assay, we observed that 0.05 microM DP increased the cytotoxicity of FUDR by a median of 33.5-fold vs 1.5-fold for 5FU against human colon-cancer cell lines. The mechanism of the DP-enhanced antitumor activity of FUDR is not completely understood but appears to be related to a profound inhibition by DP of thymidine accumulation in and FUDR efflux from colon-cancer cell lines. On the basis of these in vitro results, 28 patients with metastatic colon cancer were entered in a clinical trial of monthly courses of 0.1 mg/kg FUDR daily for 14 days and 75 mg oral DP 5 times daily for 14 days starting on the 3rd day of continuous i.v. FUDR infusion. The pharmacokinetics of DP was studied in three patients; the results showed that 98% of total serum DP was protein-bound and that free DP levels were significantly lower than the concentrations necessary for the expected in vitro DP/FUDR modulation. Treatment was well tolerated, with only 12 patients developing mild to moderate toxicity. Of 27 evaluable patients, 4 achieved a partial response that lasted 2, 3, 5, and 6+ months. This relatively low response rate (15%), which is similar to that achieved with FUDR alone, may be explained by the low steady-state plasma concentrations of free DP achieved in our patients. Other means of DP administration, such as i.v., i.a., and i.p. injection, may be required to achieve free DP concentrations necessary for successful biochemical modulation of FUDR in patients.

Bone Marrow↗
PubMedDate not supplied

Inducible nitric oxide synthase induction in Thy 1 glomerulonephritis is complement and reactive oxygen species dependent.

Thy 1 glomerulonephritis (GN) is a rat model of complement-dependent immune mesangial injury with induced glomerular nitric oxide (NO) synthesis. To examine mechanisms of inducible nitric oxide synthase (iNOS) induction, we studied the effects of treatment with the antioxidant N-acetyl-cysteine (NAC) and soluble complement receptor 1 (sCR1). Thy 1 GN was induced by intravenous anti-Thy 1 antibody. Glomeruli were isolated and kidney tissue taken from 30 min to 24 h after induction. Nitrite (NO-2) synthesis, luminol chemiluminescence for reactive oxygen species (ROS), and iNOS and cytokine mRNA were assayed in isolated glomeruli. Mesangial injury (mesangiolysis) and leucocyte infiltration were quantitated on tissue sections. NAC (i.p. 1,000 mg/kg, 1 h prior to anti-Thy 1) reduced glomerular NO-2 synthesis (3.5 +/- 0.66 vs. untreated 8.2 +/- 1.1, p = 0.02), and iNOS mRNA expression, and abolished enhanced chemiluminescence. In vitro incubation of nephritic glomeruli with 20 mM NAC also suppressed nitrite production (4.7 +/- 0.8 vs. untreated 12.2 +/- 0. 7 nmol NO-2/2,000 glomeruli/48 h, p = 0.003), and chemiluminescence. In NAC-treated animals, neutrophil infiltration (0.5 +/- 0 vs. untreated 9.6 +/- 1.6 glomerulus, p = 0.0005), and macrophage infiltration (1.7 +/- 0.4 vs. untreated 12.0 +/- 0.1, p = 0.006) were abolished, and mesangiolysis was significantly reduced (45.9 +/- 1.3 vs. untreated 34.4 +/- 2.1 cells/glomerulus, p = 0.009). NAC did not inhibit anti-Thy 1 antibody deposition. C1q was unaffected, but C3 was reduced. sCR1 treatment prevented iNOS mRNA induction, the enhanced chemiluminescence, and the neutrophil infiltration at 1 h. IL-1beta and TNFalpha mRNAs were not affected by either NAC or sCR1. These results show that NAC inhibits iNOS induction and NO synthesis in this model, and suppresses ROS synthesis and injury. They suggest that complement-dependent ROS generation is the critical initiating event that follows fixation of anti-Thy 1 antibody.

Acetylcysteine↗