Myeloperoxidase-positive Cells Research Articles

Granulocyte colony‐stimulating factor promotes the translocation of protein kinase Cι in neutrophilic differentiation cells

Previously, we suggested that the phosphatidylinositol 3-kinase (PI3K)-p70 S6 kinase (p70 S6K) pathway plays an important role in granulocyte colony-stimulating factor (G-CSF)-dependent enhancement of the neutrophilic differentiation and proliferation of HL-60 cells. While atypical protein kinase C (PKC) has been reported to be a regulator of p70 S6K, abundant expression of PKCiota was observed in myeloid and lymphoid cells. Therefore, we analyzed the participation of PKCiota in G-CSF-dependent proliferation. The maximum stimulation of PKCiota was observed from 15 to 30 min after the addition of G-CSF. From 5 to 15 min into this lag time, PKCiota was found to translocate from the nucleus to the membrane. At 30 min it re-translocated to the cytosol. This dynamic translocation of PKCiota was also observed in G-CSF-stimulated myeloperoxidase-positive cells differentiated from cord blood cells. Small interfering RNA for PKCiota inhibited G-CSF-induced proliferation and the promotion of neutrophilic differentiation of HL-60 cells. These data indicate that the G-CSF-induced dynamic translocation and activation processes of PKCiota are important to neutrophilic proliferation.

Hydroxyethyl Starch Exhibits Antiinflammatory Effects in the Intestines of Endotoxemic Rats

We performed the present in vivo study to investigate the effect of hydroxyethyl starch (HES) on intestinal production of inflammatory mediators and activation of transcription factors during endotoxemia. Rats with endotoxemia induced by lipopolysaccharide (LPS) (5 mg/kg, IV) were treated with HES (16 mL/kg, IV) or saline (64 mL/kg, IV). At 2, 3, or 6 h after the LPS challenge, the rat ileal tissues were collected. Various ileal inflammatory mediator levels (tumor necrosis factor-alpha, interleukin [IL]-6, cytokine-induced neutrophil chemoattractant-1, and IL-10), inflammatory mediator messenger RNAs (mRNAs), activities of nuclear factor (NF)-kappaB and activator protein (AP)-1, and ileal myeloperoxidase-positive cells were determined in each group. HES significantly reduced the increased intestinal levels of tumor necrosis factor-alpha, IL-6, cytokine-induced neutrophil chemoattractant-1, and the mRNAs in the endotoxemic rats. Similarly, HES could decrease the myeloperoxidase-positive cells induced by LPS and also inhibit ileal NF-kappaB and AP-1 activations. Our results suggest that during endotoxemia HES may down-regulate intestinal inflammatory mediator production, and this antiinflammatory effect of HES may act through suppression of NF-kappaB and AP-1 activations.

Increased oxidative stress in asymptomatic current chronic smokers and GOLD stage 0 COPD

BackgroundChronic obstructive pulmonary disease (COPD) is associated with increased oxidative and nitrosative stress. The aim of our study was to assess the importance of these factors in the airways of healthy smokers and symptomatic smokers without airway obstruction, i.e. individuals with GOLD stage 0 COPD.MethodsExhaled NO (FENO) and induced sputum samples were collected from 22 current smokers (13 healthy smokers without any respiratory symptoms and 9 with symptoms i.e. stage 0 COPD) and 22 healthy age-matched non-smokers (11 never smokers and 11 ex-smokers). Sputum cell differential counts, and expressions of inducible nitric oxide synthase (iNOS), myeloperoxidase (MPO), nitrotyrosine and 4-hydroxy-2-nonenal (4-HNE) were analysed from cytospins by immunocytochemistry. Eosinophil cationic protein (ECP) and lactoferrin were measured from sputum supernatants by ELISA.ResultsFENO was significantly decreased in smokers, mean (SD) 11.0 (6.7) ppb, compared to non-smokers, 22.9 (10.0), p < 0.0001. Induced sputum showed increased levels of neutrophils (p = 0.01) and elevated numbers of iNOS (p = 0.004), MPO (p = 0.003), nitrotyrosine (p = 0.003), and 4-HNE (p = 0.03) positive cells in smokers when compared to non-smokers. Sputum lactoferrin levels were also higher in smokers than in non-smokers (p = 0.02). Furthermore, we noted four negative correlations between FENO and 1) total neutrophils (r = -0.367, p = 0.02), 2) positive cells for iNOS (r = -0.503, p = 0.005), 3) MPO (r = -0.547, p = 0.008), and 4) nitrotyrosine (r = -0.424, p = 0.03). However, no major differences were found between never smokers and ex-smokers or between healthy smokers and stage 0 COPD patients.ConclusionOur results clearly indicate that several markers of oxidative/nitrosative stress are increased in current cigarette smokers compared to non-smokers and no major differences can be observed in these biomarkers between non-symptomatic smokers and subjects with GOLD stage 0 COPD.

Anti‐proliferative and anti‐inflammatory effects of topical MAPK inhibition in arterialized vein grafts

Vein graft failure following bypass surgery is a frequent and important clinical problem. The vascular injury caused by arterialization is responsible for vein graft intimal hyperplasia, a lesion generated by medial smooth muscle cell proliferation and migration into the intima, increased extracellular matrix deposition, and formation of a thick neointima. Development of the neointima into a typical atherosclerotic lesion and consequent stenosis ultimately result in vein graft failure. Endothelial damage, inflammation, and intracellular signaling through mitogen-activated protein kinases (MAPKs) have been implicated in the early stages of this process. We therefore investigated the effects of topical inhibition of ERK-1/2 MAPK activation on vascular cell proliferation and apoptosis, and on the inflammatory response in a canine model of vein graft arterialization. For this purpose, vein grafts were incubated with the MEK-1/2 inhibitor, UO126, ex vivo for 30 min before grafting. This treatment effectively abolished arterialization-induced ERK-1/2 activation, decreased medial cell proliferation, and increased apoptosis. UO126 treatment also inhibited the vein graft infiltration by myeloperoxidase-positive inflammatory cells that follows vein graft arterialization. Thus, topical ex vivo administration of MAPK inhibitors can provide a pharmacological tool to prevent or reduce the vascular cell responses that lead to vein graft intimal hyperplasia and graft failure.

Disruption of P-Selectin Signaling Modulates Cell Trafficking and Results in Improved Outcomes after Mouse Warm Intestinal Ischemia and Reperfusion Injury

This study analyzes the role of T lymphocytes and neutrophils (PMN) in intestinal ischemia and reperfusion injury (IRI) using either P-selectin blockade or elimination. Using a model of severe mouse warm intestinal IRI, the following groups were performed: group 1: wild type C57BL6 no treatment; group 2: wild type treated with r-PSGL1-Ig; group 3: C57BL6 genetically deficient in P-selectin. Survival was assessed at day 7; intestine was assayed for histopathology, apoptosis, myeloperoxidase (MPO), inflammatory cytokines, hemoxygenase-1 (HO-1), and CD3 lymphocytes. Standard statistical comparison was undertaken. The survival was significantly (P < 0.01) improved in the treatment groups: group 1, 50%; group 2, 90%; group 3, 100%. Graded histopathology and crypt apoptosis were improved in groups 2 and 3. MPO and CD3 positive cells were significantly reduced in groups 2 and 3. A significant reduction in inflammatory/Th1-type cytokines was seen in groups 2 and 3 as compared to group 1. Conversely, a significant increase in Th2-type cytokines and HO-1 production was seen selectively in groups 2 and 3. This study demonstrates the importance of P-selectin signaling in warm, murine intestinal IRI in that either the blockade of or the genetic deficiency in P-selectin confers a survival advantage and reduction in tissue injury/inflammation. The mechanism involves a reduction of PMN and CD3 T cell infiltration and an alteration in the cytokine microenvironment in favor of a Th2 profile. These data implicate T lymphocyte as an important regulatory cell in this inflammatory process.

A free radical scavenger, edaravone (MCI-186), diminishes intestinal neutrophil lipid peroxidation and bacterial translocation in a rat hemorrhagic shock model*

To investigate the effects of edaravone, a novel free radical scavenger, on bacterial translocation induced by hemorrhagic shock. Prospective, randomized, unblinded animal study. Surgical research laboratories of Shiga University of Medical Science. Male specific-pathogen-free Sprague-Dawley rats. The rats were randomly divided into three groups: conventional saline treatment, edaravone treatment, and sham shock induction. The saline and edaravone groups were subjected to hemorrhagic shock (mean arterial pressure of 30 mm Hg, for 30 or 60 mins). Rats were killed 30 or 60 mins after shock induction. Mesenteric lymph nodes were cultured for determination of bacterial translocation. Systemic plasma silkworm larvae plasma test, which can detect peptidoglycan and beta-glucan, and endotoxin tests were performed. Immunohistochemistry for 4-hydroxy-2-nonenal (4-HNE) was used to assess lipid peroxidation after shock. The incidence and magnitude of hemorrhagic-shock-induced bacterial translocation to mesenteric lymph nodes were reduced by edaravone. Hemorrhagic-shock-induced increase of plasma silkworm larvae plasma test was also reduced by edaravone. Immunohistochemistry for 4-HNE showed many 4-HNE-positive cells in the lamina propria of the ileum 60 mins after hemorrhagic shock. Double immunohistochemistry revealed that many of these 4-HNE-positive cells were also myeloperoxidase positive. Moreover, the percentage of double-labeled cells with 4-HNE and myeloperoxidase in myeloperoxidase-positive cells was significantly lower in the edaravone group than in the saline group. The present findings suggest that lipid peroxidation of intestinal neutrophils is involved in bacterial translocation during hemorrhagic shock and that edaravone is potentially useful in diminishing bacterial translocation after hemorrhagic shock.

Frequent cellular senescence in small bile ducts in primary biliary cirrhosis: a possible role in bile duct loss

The pathogenesis of progressive bile duct loss in primary biliary cirrhosis remains unclear. In this study, the involvement of cellular senescence of biliary epithelial cells was examined in liver tissue samples from patients with primary biliary cirrhosis (n = 33), and compared with control diseased and normal livers (n = 83). In addition, cellular senescence was induced by oxidative stress in cultured mouse biliary epithelial cells. Biliary epithelial cells in small bile ducts in primary biliary cirrhosis, especially those in patients presenting with chronic non-suppurative cholangitis, frequently expressed senescence-associated beta-galactosidase, and senescence-associated p16(INK4) and p21(WAF1/CIP). In contrast, senescence-associated markers were rarely expressed in small bile ducts in control livers. The infiltration of myeloperoxidase-positive inflammatory cells into biliary epithelial cell layers was closely associated with the cellular senescence of biliary epithelial cells in early-stage PBC. Cellular senescence of cultured mouse biliary epithelial cells was induced by treatment with H2O2 via the p38MAPK-dependent pathway and nitric oxide-augmented H2O2-induced cellular senescence. Oxidative stress- and nitric oxide-mediated cellular senescence may be involved in bile duct lesions, which are followed by progressive bile duct loss in primary biliary cirrhosis.

Celecoxib Induces Functional Recovery after Intracerebral Hemorrhage with Reduction of Brain Edema and Perihematomal Cell Death

The selective cyclooxygenase-2 (COX-2) inhibitor has been reported to have antiinflammatory, neuroprotective, and antioxidant effects in ischemia models. In this study, the authors examined whether a selective COX-2 inhibitor (celecoxib) reduces cerebral inflammation and edema after intracerebral hemorrhage (ICH), and whether functional recovery is sustained with longer treatment. ICH was induced using collagenase in adult rats. Celecoxib (10 or 20 mg/kg) was administered intraperitoneally 20 minutes, 6 hours, and 24 hours after ICH and then daily thereafter. Seventy-two hours after ICH induction, the rats were killed for histologic assessment and measurement of brain edema and prostaglandin E2. Behavioral tests were performed before and 1, 7, 14, 21, and 28 days after ICH. The brain water content of celecoxib-treated rats decreased both in lesioned and nonlesioned hemispheres in a dose-dependent manner. Compared with the ICH-only group, the number of TUNEL-positive, myeloperoxidase-positive, or OX42-positive cells was decreased in the periphery of hematoma and brain prostaglandin E2 level was reduced in the celecoxib-treated group. Celecoxib-treated rats recovered better by the behavioral tests at 7 days after ICH throughout the 28-day period, and the earlier the drug was administered, the better the functional recovery. Evidence of similar effects in an autologous blood-injected model showed that direct collagenase toxicity was not the major cause of inflammation or cell death. These data suggest that celecoxib treatment after ICH reduces prostaglandin E2 production, brain edema, inflammation, and perihematomal cell death in the perihematomal zone and induces better functional recovery.

Indocyanine Green Fluorescence Measurement of Intestinal Transit and Gut Perfusion after Intestinal Manipulation

Background and Aims: Postoperative ileus is a common and poorly understood problem of abdominal surgery. The aim of this study was to measure postoperative intestinal transit and to evaluate bowel wall perfusion by a novel in vivo indocyanine green (ICG)-fluorescence measurement following intestinal manipulation (IM). Methods: Rats underwent a simple intestinal manipulation. Myeloperoxidase-positive cells in the muscularis were stained with the Hanker-Yates reaction and quantified histochemically. Bowel wall perfusion was determined directly and 24 h postoperatively using a laser-fluorescence detection unit. Intestinal transit was visualized 24 h after IM. Results: IM resulted in a massive infiltration (155-fold) of neutrophils into the intestinal muscularis 24 h postoperatively. Bowel wall perfusion significantly decreased directly and 24 h following surgery (29 and 59%, respectively). Gastrointestinal transit was similarly impaired and showed a reduction to 40% of the control values 24 h after IM. Conclusion: IM of the rat small intestine caused an impairment in bowel wall perfusion and microcirculation and a significant decrease in gastrointestinal transit. The ICG fluorescence measurement using the described system proved to be a simple and reliable method to evaluate intestinal transit and bowel wall microcirculation in vivo.

Myeloperoxidase–Positive Inflammatory Cells Participate in Bile Duct Damage in Primary Biliary Cirrhosis Through Nitric Oxide–Mediated Reactions

Previous studies have suggested that increased nitric oxide (NO)–mediated products are found in the livers of subjects with primary biliary cirrhosis (PBC), but the mechanisms involved remain enigmatic. We took advantage of immunohistochemistry and several unique monoclonal antibodies to study inflammatory cells responsible for the generation of NO, the enzymes responsible for NO production, the expression of 3–nitrotyrosine, and the presence of CD68+ and/or myeloperoxidase (MPO)+ cells. We examined a total of 113 liver specimens, including 64 with PBC, 19 with primary sclerosing cholangitis (PSC), 6 with non–A, non–B hepatitis, 6 with alcoholic liver disease, 4 with cryptogenic cirrhosis, 4 with biliary atresia, and 10 normal subjects. Twenty–two percent of PBC had elevated expression of 3–nitrotyrosine in their bile duct epithelial cells (BECs) (P = .0316). Furthermore, the BECs in PBC also demonstrated apoptotic changes. MPO–positive inflammatory cells were also noted adjacent to the basement membrane. In contrast, the liver of normal subjects showed few apoptotic changes in the bile ducts, with no evidence of MPO staining in the portal area. Furthermore, sections from livers of subjects with stage I or stage II PBC demonstrated significantly increased inflammatory cell infiltration (P = .0064) and elevated 3–nitrotyrosine expression in BECs (P = .0246) compared with stage III and IV. The presence of 3–nitrotyrosine was closely associated with infiltrating CD68– and/or MPO–positive cells. There was also a stage–associated difference in the presence of bile duct infiltrating cells and 3–nitrotyrosine in PBC with an increase dominant in early stage disease. In conclusion, NO and reactive oxygen species, collectively determined as 3–nitrotyrosine, are associated with bile duct destruction in PBC and are particularly prevalent in early stage disease.

Myeloperoxidase-positive inflammatory cells participate in bile duct damage in primary biliary cirrhosis through nitric oxide-mediated reactions

Previous studies have suggested that increased nitric oxide (NO)-mediated products are found in the livers of subjects with primary biliary cirrhosis (PBC), but the mechanisms involved remain enigmatic. We took advantage of immunohistochemistry and several unique monoclonal antibodies to study inflammatory cells responsible for the generation of NO, the enzymes responsible for NO production, the expression of 3-nitrotyrosine, and the presence of CD68 + and/or myeloperoxidase (MPO) + cells. We examined a total of 113 liver specimens, including 64 with PBC, 19 with primary sclerosing cholangitis (PSC), 6 with non-A, non-B hepatitis, 6 with alcoholic liver disease, 4 with cryptogenic cirrhosis, 4 with biliary atresia, and 10 normal subjects. Twenty-two percent of PBC had elevated expression of 3-nitrotyrosine in their bile duct epithelial cells (BECs) ( P = .0316). Furthermore, the BECs in PBC also demonstrated apoptotic changes. MPO-positive inflammatory cells were also noted adjacent to the basement membrane. In contrast, the liver of normal subjects showed few apoptotic changes in the bile ducts, with no evidence of MPO staining in the portal area. Furthermore, sections from livers of subjects with stage I or stage II PBC demonstrated significantly increased inflammatory cell infiltration ( P = .0064) and elevated 3-nitrotyrosine expression in BECs ( P = .0246) compared with stage III and IV. The presence of 3-nitrotyrosine was closely associated with infiltrating CD68- and/or MPO-positive cells. There was also a stage-associated difference in the presence of bile duct infiltrating cells and 3-nitrotyrosine in PBC with an increase dominant in early stage disease. In conclusion, NO and reactive oxygen species, collectively determined as 3-nitrotyrosine, are associated with bile duct destruction in PBC and are particularly prevalent in early stage disease. (H epatology 2003;38:1018-1025.)

The percentage of myeloperoxidase-positive blast cells is a strong independent prognostic factor in acute myeloid leukemia, even in the patients with normal karyotype.

To examine whether the percentage of myeloperoxidase (MPO)-positive blast cells is useful as a prognostic factor for acute myeloid leukemia (AML), cytochemical analysis of MPO was performed in 491 patients who were registered to the Japan Adult Leukemia Study Group-AML92 study. Patients were divided into two using the percentage of MPO-positive blast (high [>or=50%] and low (<50%)). Complete remission rates were 85.4% in the former and 64.1% in the latter (P=0.001). The overall survival (OS) and the disease-free survival (DFS) were significantly better in the high MPO group (48.3 vs 18.7% for OS, and 36.3 vs 20.1% for DFS, P<0.001, respectively). Multivariate analysis showed that both karyotype and the percentage of MPO-positive blast cells were equally important prognostic factors. The high MPO group still showed a better survival even when restricted to the intermediate chromosomal risk group or the patients with normal karyotype (P<0.001). The OS of patients with normal karyotype in the high MPO group was almost equal with that of the favorable chromosomal risk group. The percentage of MPO-positive blast cells is a simple and highly significant prognostic factor for AML patients, and especially useful to stratify patients with normal karyotype.

Delayed inflammation in rat meninges: implications for migraine pathophysiology.

Nitric oxide (NO) has been implicated in migraine pathogenesis based on the delayed development of typical migraine headache 4-6 h after infusing the NO donor nitroglycerin [glyceryl trinitrate (GTN)] to migraineurs. Furthermore, inhibiting the synthesis of NO by treatment with a NO synthase (NOS) inhibitor attenuates spontaneous migraine headaches in 67% of subjects. Because NO has been linked to inflammation and cytokine expression, we investigated the delayed consequences of brief GTN infusion (30 min) on the development of meningeal inflammation in a rat model using doses relevant to the human model. We found dose-dependent Type II NOS [inducible NOS (iNOS)] mRNA upregulation in dura mater beginning at 2 h and an increase in the corresponding protein expression at 4, 6 and 10 h after infusion. Type II NOS immunoreactivity was expressed chiefly within resident meningeal macrophages. Consistent with development of a delayed inflammatory response, we detected induction of interleukin 1beta in dura mater at 2 and 6 h and increased interleukin 6 in dural macrophages and in rat cerebrospinal fluid at 6 h after GTN infusion. Myeloperoxidase-positive cells were rarely found. Leakage of plasma proteins from dural blood vessels was first detected 4 h after GTN infusion, and this was suppressed by administering a specific Type II NOS inhibitor [L-N(6)-(1-iminoethyl)-lysine (L-NIL)]. In addition to cytokine induction, macrophage iNOS upregulation and oedema formation after GTN infusion, dural mast cells exhibited granular changes consistent with secretion at 4 and 6 h. Because iNOS was expressed in dural macrophages following topical GTN, and in the spleen after intravenous injection, the data suggest that the inflammatory response is mediated by direct actions on the dura and does not develop secondary to events within the brain. Our findings point to the importance of new gene expression and cytokine expression as fundamental to the delayed response following GTN infusion, and support the hypothesis that a similar response develops in human meninges after GTN challenge.

Systemic complement depletion diminishes perihematomal brain edema in rats.

The complement cascade is activated after experimental intracerebral hemorrhage (ICH). It remains unclear, however, whether depleting the complement system will improve injury resulting from ICH. This study investigated the effects of systemic complement depletion on brain edema formation after ICH. Fifty-six pentobarbital-anesthetized Sprague-Dawley rats were used. Treatment animals were complement-depleted with cobra venom factor (CVF) (intraperitoneally). Control rats received an equal volume of saline injection (intraperitoneally). In both treatment and control rats, autologous blood (100 microL) was infused stereotaxically into the right basal ganglia. Rats were killed 2, 24, or 72 hours later for brain water, ion, and tumor necrosis factor-alpha (TNF-alpha) measurements, for Western blot analysis, and for immunohistochemical studies. Brain edema was quantitated by wet/dry weight. TNF-alpha levels were measured by enzyme-linked immunosorbent assay. Western blot analysis was applied for C9 semiquantification. Immunohistochemistry was used to detect complement C3d, C5a, C9, and myeloperoxidase. Perihematomal brain edema was reduced by systemic complement depletion at 24 hours (78.8+/-0.6% versus 81.5+/-0.8% in control, P:<0.01) and 72 hours (81.5+/-1.5% versus 83.6+/-0.9% in control, P:<0.05), while cerebellar water content was unaffected (78.2+/-0.3% versus 78.0+/-0. 1%). Complement depletion reduced TNF-alpha production 2 hours after ICH. Immunocytochemistry showed that complement depletion significantly reduced perihematomal C9 deposition, C3d production, and the number of C5a- and myeloperoxidase-positive cells. Complement depletion by CVF attenuates brain edema in ICH, indicating that complement activation plays an important role in ICH-induced brain edema. Preventing complement activation may be effective in the treatment of ICH.

Expression of ICAM-1 and acute inflammatory cell infiltration in the early phase of radiation colitis in rats.

Inflammatory cell infiltration of the colon is observed at an early stage of radiation-induced colitis. The emigration of inflammatory cells from the circulation requires interactions between cell adhesion molecules on the vascular endothelium and molecules on the surface of leukocytes. To elucidate this process, the present work analyzes the kinetics of the expression of intercellular adhesion molecule-1 (ICAM-1) and the accumulation of inflammatory myeloperoxidase (MPO)-positive cells in relation to the appearance of acute radiation colitis prior to an overt radiation-induced ulcer. Colon tissues were obtained from Wistar Kyoto rats at various times after 22.5 Gy irradiation to the rectum. Histologically, crypt depletion and numerous inflammatory cells were observed 4 days after irradiation, and mucosal ulcer 6 days after irradiation. ICAM-1 immunopositivity was present in the endothelial cells of small vessels in the mucosa of both control and irradiated rats. ICAM-1 mRNA expression was detected in normal colon and irradiated colon by reverse transcription-PCR. In Northern blotting, ICAM-1 mRNA levels were found to increase markedly in the irradiated colon compared to the normal colon. In Western blotting. ICAM-1 protein expression also increased with a peak one day after irradiation, and remained elevated up to 6 days thereafter. The number of MPO-positive cells in lamina propria mucosa increased in a time-dependent fashion from 6 h to 6 days after irradiation. These data suggest that up-regulation of ICAM-1 in endothelial cells and accumulation of MPO positive cells play important roles in the development of radiation-induced colonic ulcer.

The synthetic somatostatin analogue, octreotide, ameliorates acute and delayed intestinal radiation injury

Purpose: Reducing intraluminal proteolytic activity attenuates intestinal radiation toxicity. This study assessed whether pharmacological inhibition of exocrine pancreatic secretion protects against early and delayed radiation enteropathy in a preclinical rat model. Methods and Materials: Rat ileum was sham-irradiated or exposed to 16 once-daily 4.2 Gy fractions of X-radiation. Vehicle or somatostatin analogue (octreotide, 2 μg/kg/hr) were administered from 2 days prior to 10 days after the end of irradiation. Mucosal injury was monitored noninvasively by assessment of granulocyte transmigration. Radiation injury was assessed at 2 weeks (early phase) and 26 weeks (chronic phase) using quantitative histopathology, immunohistochemistry, and morphometry. Results: Octreotide decreased granulocyte transmigration ( p < 0.0006), reduced accumulation of myeloperoxidase-positive cells at 2 weeks ( p = 0.0002), attenuated structural injury at 2 weeks ( p = 0.04) and 26 weeks ( p = 0.02), preserved mucosal surface area at 2 weeks ( p = 0.0008) and 26 weeks ( p = 0.0008), and reduced intestinal wall thickening at 26 weeks ( p = 0.002). Octreotide did not affect granulocyte transmigration, histology, or mucosal surface area in sham-irradiated controls. Conclusion: These results demonstrate the importance of consequential mechanisms in the pathogenesis of chronic radiation enteropathy. Short-term octreotide administration ameliorates acute radiation-induced mucosal injury, as well as chronic structural changes, and should be subject to further preclinical and clinical testing.

Neutrophil infiltration into human gliomas.

Human gliomas were analysed for the infiltration of neutrophils using immunohistochemistry by staining sections for CD15-positive and myeloperoxidase-positive cells. Over 70% of all glioma samples analysed (n = 105) had significant neutrophil infiltration, but there was a marked and significant correlation between tumour grade and the extent of the neutrophil infiltration. In the low grade tumours only 40-50% had significant infiltration, while in glioblastoma multiforme over 85% of the samples analysed had significant infiltration. Numbers of neutrophils infiltrating glioblastoma multiforme tumours were also greater than in the other tumour groups. Circulating white blood cell counts were elevated above the normal range in all glioma patients, but this elevation was entirely due to increased numbers of circulating neutrophils. Again, the highest numbers of circulating neutrophils were seen in the glioblastoma multiforme patients. These experiments indicate that glioma-derived factors may directly or indirectly affect the number of circulating neutrophils and influence their infiltration into the tumours.

Myelodysplastic syndrome with signs of auto-immune disease in a patient with renal allograft

Sir:We report on a 19-year-old patient who has been treated in our hospital since 1986. At the age of 11 years he presented with acute renal failure due to extracapillary glomerulonephritis with intrarenal vasculitis consistent with peri arteritis nodosa. No other clinical signs of auto-immune vasculitis were present at that time. After 2 years of haemodialysis renal transplantation was performed in 1988. Immunosuppressive therapy consisted of prednisone, azathioprin and cyclosporine A. In May 1994 the patient was admitted to our hospital because of unexplained fever. Clinical history was uneventful except for a panaritium, which had been treated with oral antibiotics. Blood count revealed thrombocytopenia (92/nl). He had recurrent episodes of high fever, but showed no other clinical signs of infection. WBC was low (3.7±4.0/nl), erythrocytes were reduced (1.9±2.3/pl), platelets were in the range of 42±65/nl, ESR was high (91/121), C-reactive protein was elevated (1.1±5.3 mg/dl). Serological investigation for bacterial or viral infection was negative. Blood and urine cultures were negative. Creatinine was 1.5 mg/dl on several occasions and thus unchanged compared to previous examinations; other blood chemistries gave normal results. Antinuclear antibodies (ANA) (1:160) and antiplatelet antibodies against glycoprotein Ib/IX were positive. Direct Coombs test was positive (IgG-antibodies), indirect Coombs test was negative. Antibodies against doublestranded DNA and extractable nuclear antigens were negative. No circulating immune complexes were found, but atypical anti-neutrophilic cytoplasmatic antibodies were detected. C3 and C4 were normal, complement activity was 90%. Skin biopsy showed no immune deposits. A needle biopsy of the allograft showed the same pattern of chronic rejection as 2 years before. Subsequently, the patient developed hepatosplenomegaly and severe weight loss. Repeated bone marrow aspiration disclosed myelodysplastic syndrome (MDS) which was classi®ed as refractory anaemia with excess of blasts (8%) and pronounced haemophagocytosis ± RAEB according to the French-American-British (FAB) classi®cation. Cytogenetic analysis showed a normal karyotype. No distinct blast cell population could be de®ned by immunophenotyping, nor was the integration of EBV genome (EBV-encoded-RNA) detected. Chemotherapy was started with cyclophosphamide, adriamycin, vincristine and prednisolone. During chemotherapy the patient developed acute renal failure and septicaemia. Despite intensive care treatment the patient died due to septic shock with multiorgan failure. Post mortem analysis of the bone marrow revealed 30% blast cells which were positive for myeloperoxidase. Analysis of the spleen showed myeloperoxidase-positive blast cells as well, which were CD 20 and CD 3 negative. Lymph nodes and liver showed similar results. It is well known that immunosuppressed individuals are at increased risk for the occurrence of haematological malignancies. However, incidence, prevalence and presentation are variable and may be in uenced by the intensity of immunosuppression administered, the intrinsic characteristics of the graft recipient and other yet undetermined factors [4]. Retrospective analyses have calculated frequencies up to 7.9% for developing malignancies in adult renal graft recipients [2], whereas in children the frequency varies from 0.8% to 1.3% [6]. Carcinoma of the skin, MDS, lymphoma and acute leukaemia are the most frequent malignancies which tend to occur during immunosuppressive therapy [2, 3, 5]. In our patient the association of anaemia, thrombocytopenia, fever and immunological parameters with the results of bone marrow analysis suggest an auto-immune disease coinciding with MDS. The immunological disturbances in patients with MDS may predispose them to the manifestation of auto-immune diseases [1]. After establishing auto-immunological features in MDS the use of immunosuppressive drugs for their treatment must be questioned since they could convert the myelodysplasia into frank leukaemia.

CD7+ stem cell leukemia/lymphoma. Features of a subgroup without circulating blast cells

Recent advances in immunology have clarified the cellular origin of hematopoietic neoplasms. Blast cells with a CD7+ CD4- CD8- phenotype are demonstrated to originate from malignant pluripotent hematopoietic stem cells. In this article, the authors describe three rare cases, designated as a lymphoma type of CD7+ stem cell leukemia/lymphoma, with clinical features described below. All three patients were admitted with non-Hodgkin lymphoma with a 2-month to 4-month history of lymphadenopathy. Histologic examination of lymph nodes showed lymphoblastic lymphoma (LBL) in all patients. Bone marrow blast cells had an immunophenotype consistent with CD7+ CD4- CD8- acute leukemia, although abnormal cells were not observed in the peripheral blood during the course of the disease. One patient had a recurrence in the bone marrow, with myeloperoxidase-positive blast cells expressing myeloid differentiation antigens. Chromosomal analysis detected a common abnormal karyotype initially and at relapse. Furthermore, the same T-cell receptor gene rearrangement was found initially and at relapse, suggesting that these blast cells originated from the same pluripotent leukemic clone. Additional studies on more patients are required to determine the clinical significance of this group, including the difference from CD7+ stem cell leukemia/lymphoma with circulating blast cells (leukemic type) or LBL.

Platelet-activating factor-induced mucosal dysfunction: role of oxidants and granulocytes.

We tested the possibility that platelet-activating factor (PAF) exerts some of its actions on the microvascular and mucosal membranes by stimulating the production of reactive O2 metabolites. Two series of experiments were performed using autoperfused segments of cat ileum pretreated with human recombinant superoxide dismutase (hSOD), catalase (H2O2 scavenger), or deferoxamine (an iron chelator). In the first series, we examined the effects of PAF infusion on mucosal permeability (blood-to-lumen clearance) to 51Cr-EDTA. PAF induced a 4-, 25-, and 20-fold increase in 51Cr-EDTA clearance at 4, 20, and 40 ng/min, respectively, and the increase was positively correlated with luminal fluid flux. hSOD, catalase, and deferoxamine reduced the 51Cr-EDTA clearance at each PAF dose and eliminated the dependence of 51Cr-EDTA clearance on transmucosal fluid flux. To determine whether mucosal granulocytes were the source of the reactive O2 metabolites, the mucosa was depleted of myeloperoxidase-positive cells using an antibody against the leukocyte integrin CD11/CD18. Mucosal granulocyte depletion resulted in a greatly reduced clearance of 51Cr-EDTA, suggesting that resident granulocytes may be the source of the reactive O2 metabolites. In a second series of studies, we examined the influence of hSOD, catalase, and deferoxamine on the increased transcapillary fluid and protein fluxes induced by intra-arterial PAF infusion. These agents attenuated the enhanced transvascular fluid and protein filtration by greater than 50% at the low dose but had no effect at the higher doses. We conclude that the PAF-induced increase in mucosal permeability to 51Cr-EDTA is mediated by reactive O2 metabolites produced by resident phagocytic cells.(ABSTRACT TRUNCATED AT 250 WORDS)