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M Mariano

Publications and source records attributed to M Mariano.

At least 37 records · Page 2Linked to original sources
PubMed1997

A new murine model of pulmonary eosinophilic hypersensitivity: contribution to experimental asthma.

BACKGROUND: We have recently described a model of hypersensitivity reaction in the mouse paw, which induces a typical late-phase reaction with a marked eosinophilic infiltrate. OBJECTIVE: In the search for a murine model of asthma, this model was adapted to the lungs and compared with other models of pulmonary hypersensitivity. METHODS: A fragment of heat-coagulated hen's egg white was implanted subcutaneously, and 14 days later, the mice were challenged intratracheally with aggregated ovalbumin. Comparison was made with a group that received subcutaneous injection of soluble ovalbumin in alumen, challenged as described above and with four additional protocols of immunization and challenge. RESULTS: Forty-eight hours after challenge, the percentage of eosinophils was higher in the egg white implant group (35%) than in the group immunized with ovalbumin in alumen (10.4%). The eosinophil peroxidase activity in lung homogenates of the first group was also significantly higher (529 ng/ml) than that of the second group (43 ng/ml). These results were reproduced in five different mouse strains. Compared with five different models of lung hypersensitivity, the egg white implant model was unique in terms of persistence of the pulmonary eosinophilia. Histopathologic analysis of the lungs of mice immunized with egg white implant showed peribronchial, perivascular, and intraepithelial eosinophil infiltration; morphologic characteristics of bronchoconstriction; and patchy epithelial shedding. At 21 days, in addition to persistence of eosinophil infiltrate, enlarged alveoli, reflecting air trapping, were observed. CONCLUSION: On the basis of the characteristics of the model described here, we propose it as a suitable murine model of asthma.

Administration, Cutaneous↗
PubMed1997

Lipids from Mycobacterium leprae cell wall suppress T-cell activation in vivo and in vitro.

The influence of Mycobacterium leprae cell wall lipids on lymphocyte functions has been investigated in vivo (delayed-type hypersensitivity) and in vitro. The inflammatory response has been earlier evaluated by the mouse footpad oedema model and the delipidated mycobacteria evoked a mild but significant inflammatory response. Herein a higher level of hypersensitivity reaction was observed with delipidated bacilli than with the intact mycobacteria. The lipids obtained from the extract of M. leprae external cell wall were used to prepare liposomes, which have not been shown to be toxic to lymphocytes. The method of lipidic extraction and the sodium dodecyl sulphate-polyacrylamide gel electrophoresis of the lipid fraction did not reveal any trace of proteins. Thin-layer chromatography of this extract detected four different bands with an apolar character, suggestive of mycolic and fatty acids. These same M. leprae liposomes potently suppressed lymph node cells, as well CD4+ and CD8+ T-cell lines, and an antigen-specific T-cell clone (T 4-9) proliferation, even under potent stimulus. Cholesterol-choline liposomes, unrelated to M. leprae liposomes, used as a control in the biological assays showed no significant effect on lymphoblastic activity, which points to the specificity of M. leprae lipids. These data demonstrated that M. leprae cell wall lipids induce immune suppression in mice without causing any membrane alteration in T cells as assessed throughout kinetic studies in vitro. This fact is closely related to the down-regulating effect induced by M. leprae lipids which we have previously observed in macrophage functions in vivo and in vitro. Although this lipidic fraction showed a suppressive action on T lymphocytes in vitro (proliferation) and in vivo (delayed-type hypersensitivity), its possible significance in the establishment of a specific immune response to M. leprae must be further investigated.

Animals↗
PubMed1997

Down-regulatory effect of Mycobacterium leprae cell wall lipids on phagocytosis, oxidative respiratory burst and tumour cell killing by mouse bone marrow derived macrophages.

The authors have previously demonstrated that lipids from Mycobacterium leprae cell walls inhibit macrophage functions and are endowed with anti-inflammatory properties in vivo. To investigate these observations further, the authors describe here the influence of dead M. leprae or of the lipids extracted from the cell wall of the mycobacterium, enclosed in liposomes, on the phagocytic, oxidative respiratory burst and tumouricidal ability of bone marrow derived macrophages in vitro. Dead M. leprae or its cell wall lipids abrogated the oxidative respiratory burst and phagocytic ability of mouse bone marrow derived macrophages. A dose-dependent inhibitory effect of the bacterial lipid extract on tumour cell killing by lipopolysaccharide (LPS)-activated bone marrow derived macrophages was demonstrated. However, when delipidated M. leprae was added to cultures of bone marrow derived macrophages, immune phagocytosis and superoxide production was up-regulated. Mycobacterium leprae or its lipids did not appear to be toxic to those cells assayed by the MTT (methyl thiazol tetrazolium) test. These data, added to our preceding observations, support the hypothesis that the down-regulatory activity of M. leprae wall lipids on macrophage function might be one of the evasive mechanisms of the bacterium to enable it to perpetuate itself in the host tissues.

Animals↗
PubMed1997

Circadian rhythm in experimental granulomatous inflammation is modulated by melatonin.

Biological rhythms are detected in a variety of physiological and pathological conditions in man and animals, such as rheumatoid arthritis and asthma. Here we describe a circadian rhythm in experimental infectious and non-infectious granuloma. After 30 days of BCG (Bacillus Calmette-Guerin) or nystatin inoculation in the left hind foot of C57B1/6 mice, there is an oscillation with a period of approximately 24 hr in the variation of paw thickness, indicating a circadian rhythm. The acrophase occurred during the light phase, between 9:00 and 13:00 hr, while the nadir occurred in the dark phase, between 21:00 and 01:00 hr. The vascular permeability around the granulomatous lesions was higher at 12:00 hr than at 24:00 hr. This is in agreement with the observation that the thickness of a paw with granulomatous lesion is larger during the light phase. This rhythmic variation was eliminated by either pinealectomy or superior cervical ganglionectomy, which greatly reduce melatonin levels in the blood. Nocturnal replacement of melatonin in pinealectomized mice led to the re-establishment of the circadian rhythm. Thus, the rhythm of the granulomatous lesion is due to the rhythmic melatonin release by the pineal gland. This approach opens new questions regarding the modulation of chronic inflammation in inflammatory diseases that present rhythmic symptoms throughout the day.

Animals↗
PubMed1997

A new murine model of persistent lung eosinophilic inflammation.

We summarize here the main characteristics of a novel model of pulmonary hypersensitivity. Mice were immunized with a subcutaneous implant of a fragment of heat solidified chicken egg white and 14 days later challenged with ovalbumin given either by aerosol or by intratracheal instillation. This procedure induces a persistent eosinophilic lung inflammation, a marked bone marrow eosinophilia, and Th2-type isotypic profile with histopathological findings that resemble human asthma. Further, this model is simple to perform, reproducible in different strains of mice, does not require adjuvants nor multiple boosters. Based on these characteristics we propose it as a suitable murine model of allergic eosinophilic lung inflammation.

Animals↗
PubMed1997

Effect of glucan on murine lupus evolution and on host resistance to Klebsiella pneumoniae.

Glucan is a polysaccharide from the yeast Saccharomyces cerevisiae that stimulates the mononuclear phagocytic system (MPS). NZB/NZW F1 mice were divided into two groups: one group received a subcutaneous injection of 0.5 mg glucan/animal for 1 week, and the other received the same dose for 3 months. No changes were observed in those animals submitted to short-term glucan treatment, whereas animals with active lupus and submitted to long-term glucan administration presented early death, with significant differences in accumulated mortality rates over 33-37 weeks, when compared to controls. No deaths were observed in lupus mice treated with glucan 24 hours before the induction of septic shock by Klebsiella pneumoniae, in contrast to mortality of 95.3% in the control group during the follow-up period of 12 days. We conclude that although glucan is able to exacerbate lupus activity, it enhances resistance to infection in lupus mice.

Animals↗
PubMed1996

Lipids from Mycobacterium leprae cell wall are endowed with an anti-inflammatory property and inhibit macrophage function in vivo.

In general, the majority of bacteria are pre-inflammatory when injected in experimental animals. However, Mycobacterium leprae has no inflammatory effect when injected into mouse footpad, but using the delipidated mycobacteria we observed a mild significant increase in footpad oedema. Other mycobacteria, Mycobacterium bovis-BCG or M. tuberculosis induce a strong paw oedema. Furthermore, M. leprae reduced locally the BCG-induced inflammatory reaction in mouse footpad, whereas delipidated M. leprae did not influence this reaction. Both M. leprae and M. leprae cell wall lipids blocked immune phagocytosis in vivo by inflammatory macrophages (from an induced focus). In contrast delipidated M. leprae stimulated the phagocytosis reaction. Neither intact M. leprae. delipidated M. leprae, nor its lipids had any toxic effect on macrophages or on cell migration. Although M. leprae did not interfere on cell influx and cell type in an induced-inflammatory site, this mycobacterium led to the appearance of a distinct cell population in vivo. The hypothesis is that M. leprae would transform macrophages in epithelioid cells, suggested by morphology analysis of cells by fluorescence-activated cell sorter and observed under optic microscopy.

Animals↗
PubMed1995

Wound repair in the Amphioxus (Branchiostoma platae), an animal deprived of inflammatory phagocytes.

The existence of phagocytes in the Amphioxus is a matter of debate since early studies of Metchnikoff, who could not induce inflammation in this animal. To reinvestigate this important phenomenon, we sectioned the distal portion of the animal and analyzed, by morphological methods, the presence of phagocytes in the wound. The analysis of the wound by optical and electron microscopy did not detect cells with morphological characteristics of phagocytes in it. The wound is completely covered by the external cuticle of the animal 24 hr after the lesion was made. A second section of the animal leads to abnormal healing of the lesion. The insertion of a surgical silk thread in the muscle of the animals results--after 13 days--in a collection of cells surrounding the foreign body. The ultrastructural analysis of these cells showed they are endothelial cells rather than specialized phagocytes. Yet, the Amphioxus is able to mount an allograph rejection when the animals are tied together by suture. This intriguing capacity of the Amphioxus to cope with tissue healing, infection, and other pathologies without phagocytes is discussed.

Animals↗
PubMed1994

Role of lymphatic drainage on the development of Calmette-Guérin bacillus-induced granulomas in the hamster.

The influence of lymphatic drainage on Calmette-Guérin bacillus (BCG)-induced granulomas was investigated by comparing the time course of granuloma formation in two sites: the hamster footpad and the check pouch, an area deprived of lymphatic vessels. Typical epithelioid granulomas developed in both sites. Whereas in the footpad the size of granulomas increased and the volume of the lesion persisted, in the pouch the lesion decreased in volume. The inoculation of BCG into the footpad of animal with granulomas in the pouch, reactivated the pouch lesions. T lymphocytes were detected by an immunocytochemical technique at the edge of these lesions. Inoculation of the bacteria into the pouch induces suppressive mechanisms which hold down the volume of the lesions induced in the footpad. The cutaneous purified protein derivative (PPD) test, positive in animals inoculated in the footpad, was always negative in animals with granulomas in the pouch. The number of bacteria per microscopic field in pouch granulomas increased from 10 to 1,000 after PPD injection. Evidence that PPD has a direct effect on pouch granuloma cells is given.

Animals↗
PubMed1993

Inflammatory responses induced by poly-L-arginine in rat lungs in vivo.

The inflammatory responses induced by the synthetic polycation poly-L-arginine injected either into the pleural cavity or into the trachea in rats have been investigated. Poly-L-arginine (4-40 nmol/rat) injected intrapleurally induced exudate formation and leucocyte migration (mainly polymorphonuclear cells). The exudate formation (but not cell migration) was dependent on the molecular weight of the poly-L-arginine used (24 and 115 kD). The poly-L-arginine-induced pleurisy was mainly dependent on activation of mast cells since it was significantly reduced either in rats depleted of their stores of histamine and serotonin or in rats previously treated with the serotonin receptor antagonist methysergide. The polyanions heparin and dermatan sulphate when administered intrapleurally with the polycation markedly reduced the exudate formation. Poly-L-arginine (115 kD, 8.5 nmol/rat) injected intratracheally caused lung oedema, increased leucocyte number and protein content of bronchoalveolar lavage, respiratory insufficiency and 60% mortality in 6 h. Depletion of histamine and serotonin stores or of circulating neutrophils decreased the leucocytes in bronchoalveolar lavage but did not increase survival rate, whereas the polyanion dermatan sulphate prevented the mortality completely. These results suggest that the inflammatory changes caused by poly-L-arginine are dependent on mast cell activation but that the lethality after intratracheal administration is due to electrostatic interactions of the polycation with anionic surfaces present in the pulmonary epithelium.

Animals↗
PubMed1993

One-step peritoneal catheter replacement in children.

The interruption of chronic peritoneal dialysis for a period of time is recommended for replacement of the peritoneal catheter due to tunnel infection and/or relapsing peritonitis. In pediatric patients, in the younger ones, in particular, discontinuation of peritoneal dialysis can be problematic--there are difficulties associated with vascular access and hemodialysis. Over a 5-year period 9 children (4 infants, 2 preschool, 3 school-age) required 15 peritoneal access device replacements, without interruption of continuous ambulatory peritoneal dialysis (CAPD). The reasons for catheter replacement were tunnel complications (10), relapsing bacterial peritonitis (3), and fungal peritonitis (2). All catheter removals and placements were performed by surgical method under general anesthesia in a one-step procedure. The new catheters were implanted on the opposite side of the abdominal wall in all except one child, who had a colostomy. All patients received prophylactic antibiotics in the bags. In the postoperative period the patients infused smaller exchange volumes during 2 weeks. In the older children the exchange volumes were increased overnight. This schedule resulted in low intra-abdominal pressure. No patient required interval hemodialysis. Relapse of tunnel infection occurred in one episode in the first 2 months. We did not observe, in the same period, recurrence of peritonitis. One-step catheter replacement has been demonstrated to be safe; it avoids the disruption of ongoing treatment and promotes patient maintenance on CAPD.

Catheters, Indwelling↗
PubMed1991

Hyperdiploidy and trisomy of chromosome 15 in peritoneal macrophages of hyperimmune, older Swiss mice.

Chromosome analysis was carried out in resident and exudate peritoneal macrophages and, also, in bone marrow cells of groups of mice either immunized with ovalbumin in complete Freund's adjuvant and challenged with the antigen, or stimulated with the irritant thioglycollic acid. Labeling of the phagocytic cells with colloidal carbon showed that dividing cells in the peritoneal cavity of experimental mice are resident macrophages. Also shown was an increase in number of hyperdiploid metaphases in hyperimmune, older mice but not in the young ones. Statistical analysis showed these differences to be significant. G-banding of hyperdiploid cells of hyperimmune older mice showed trisomy of chromosome 15 in several metaphases analyzed. The absence of hyperdiploid metaphases in the bone marrow cells of hyperimmune mice and in exudate macrophages of mice that received the irritant thioglycollic acid suggests that hyperdiploidy occurs in resident macrophages in the peritoneal cavity but not in their precursors in the bone marrow. These results raise some questions such as, hyperimmune older mice resident macrophages being prone to hyperdiploidy and trisomy of chromosome 15.

Aging↗
PubMed1990

Epithelial macrophages secrete a deactivating factor for superoxide release.

The release of superoxide anion (O2-) by inflammatory macrophages, multinucleated giant cells, and epithelioid cells, obtained by the insertion of round glass coverslips into the subcutaneous tissue of mice, was investigated. O2- was shown to be spontaneously released by cells on the surface of glass coverslips implanted up to 7 days, but not by cells obtained 14 or 21 days after coverslip implantation. The former showed increased O2- release when stimulated by phorbol myristate acetate, whereas cells harvested after 14 or 21 days implantation did not. The induction of delayed type hypersensitivity around coverslips implanted for 5 days increased spontaneous O2- release by these cells by 40%. On the other hand, when the same protocol was used with coverslips implanted for 14 days, O2- release was not detected. These results were viewed in regard to the composition of the cell population at each time point. When coverslips were removed after 14 days of implantation and the cells incubated for 30 minutes in vitro, the medium so conditioned inhibited O2- release by cells of 5 day old preparations. This indicates the release by cells on the longer term coverslips of a substance that inhibits O2- production by cells of coverslips implanted for 5 days only. This inhibitory activity could be suppressed by treating the conditioned medium with proteases. The factor was, however, heat stable and exerted its effects even when the test cells were exposed to phorbol myristate acetate.

Animals↗
PubMed1990

Lytic, agglutinating, and opsonizing effect of alpha 2-macroglobulin on sheep red blood cells.

Mouse alpha 2-macroglobulin (alpha 2M) induced agglutination and lysis of sheep red blood cells depending on temperature and time of incubation in vitro. When these erythrocytes (E) were treated with a subagglutinanting dose of alpha 2M, they were adhered to and phagocytosed by thioglycollate-elicited and BCG-activated mouse peritoneal macrophages. Phagocytosis was not observed when resident peritoneal macrophages were tested. alpha 2M also was able to dissociate sheep red blood cells previously aggregated by IgM anti-E.

Animals↗
PubMed1990

Pharmacological characterization of polycation-induced rat hind-paw oedema.

1. The inflammatory response induced by poly-L-arginine in the rat hind-paw was studied both by measuring paw oedema and histologically. 2. The paw volume was measured with a hydroplethysmometer at 0.5, 1, 2, 4, 6 and 18 h after the subplantar injection of the polycation. Protein extravasation was evaluated with Evans' blue and the histology studied by light microscopy. 3. Poly-L-arginine (12, 24, 43 and 115kD) caused dose- and molecular weight-dependent oedema which had a rapid onset and long duration. Evans' blue extravasation paralleled the oedema induced by poly-L-arginine. Microscopic examination of the paws at early stages of oedema formation showed exuberant liquid exudate with no inflammatory cells. After 18 h, a cellular infiltrate was present, consisting mainly of mononuclear cells. 4. Indomethacin, dexamethasone, BW755c or the PAF-antagonist WEB 2086 caused no significant inhibition of the poly-L-arginine-induced oedema. Cyproheptadine had inhibitory effects only on the early stages of the polycation-induced oedema. Similar results were observed with rats depleted of histamine and 5-hydroxytryptamine. 5. Heparin, a polyanion, injected in the rat paw caused a marked inhibition of the polycation-induced oedema. NG-monomethyl-L-arginine (LNMMA), an inhibitor of EDRF synthesis, injected locally also produced a marked inhibition, but this inhibition was reversed by iloprost. 6. These results suggest that the oedema induced by polycations was due to their cationic charge. The inhibitory effect of LNMMA is probably due to a decrease in vascular flow rather than a decrease in vascular permeability.

4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyraz↗
PubMed1990

Chronically inflamed tissue activates plasma mediators of vascular permeability.

1. After inflammation was induced in the foot-pad of rats with nistatin or BCG, injection of "non-activated" homologous plasma at the inflamed site caused a significant increase in the vascular permeability of the lesions (Evans blue test), which was more intense in older lesions, increasing from 7.83 +/- 1.11 to 8.70 +/- 1.18 (nistatin, 4 and 21 days) and 7.30 +/- 0.66 to 7.54 +/- 0.80 (BCG, 4 and 21 days). 2. Steroidal (acetyltriamcinolone, 2 mg/kg) and non-steroidal (indomethacin, 25 mg/kg) [corrected] anti-inflammatory drugs markedly decreased this effect on 14-day old lesions induced by nistatin plus "non-activated" plasma (2.37 +/- 0.10 for acetyltriamcinolone treatment vs 8.15 +/- 1.22 for untreated animals; 3.34 +/- 0.41 for indomethacin treatment vs 8.15 +/- 1.22 for untreated animals) and BCG plus "non-activated" plasma (1.67 +/- 0.11 for acetyltriamcinolone treatment vs 10.27 +/- 0.52 for untreated animals; 5.87 +/- 0.35 for indomethacin treatment vs 9.14 +/- 0.23 for untreated animals). 3. These data suggest that an increase in exudation in chronic lesions might result in "reactivation" of the process as observed clinically, for example, in rheumatoid arthritis in man.

Animals↗
PubMed1989

Do connective tissue components induce plasma activation in vivo?

1. This paper describes the effect of homologous plasma in contact with connective tissue on vascular permeability, edema and cell migration. 2. The contact of "non-activated" plasma with connective tissue structures does not result in generation of mediators responsible for increase in vascular permeability or in edema. 3. "Activated" plasma is able to induce vascular permeability and edema when in contact with connective tissue components. 4. Injection of "non-activated" or "activated" plasma induced a mild inflammatory cell migration.

Animals↗