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H Cejas

Publications and source records attributed to H Cejas.

14 recordsLinked to original sources
PubMed2001

Cytokines involved in the immunosuppressor period in experimental fasciolosis in rats.

The aim of this study was to evaluate the kinetics of the cytokines interferon-gamma, interleukin-2, interleukin-10 and interleukin-4 produced by spleen mononuclear cells stimulated by Con A during an experimental infection in rats with Fasciola hepatica. The proliferative response to Con A of Spm cells from rats infected with F. hepatica was significantly decreased on day 7 post-infection (P<0.006) and simultaneously an increase of interferon-gamma, interleukin-10 and interleukin-4 production along with a decrease of interleukin-2 by spleen mononuclear cells were observed. Interleukin-4 and interleukin-10 were involved in ablating cellular proliferation in vitro, as the addition of neutralising antibodies to either cytokine reversed the proliferative block. The addition of exogenous recombinant interleukin-2 also restored the proliferative response by spleen mononuclear cells obtained 7 days after infection from infected rats. At the same time, we found an increase in interleukin-10 production by peritoneal cells (in close contact with the flukes) and decreased nitric oxide levels. In addition, histological studies on the liver on day 7 after infection showed the presence of parasite inside migratory tunnels in the parenchyma, and polymorphonuclear leukocytes, predominantly eosinophils, around the parasite. The transient suppression in proliferative response mediated by cytokines interleukin-4 and interleukin-10 in the spleen, and diminution of nitric oxide production in the peritoneum could be mechanisms to evade the protective immune response during the first stages of liver penetration by the parasite.

Animals↗
PubMed2001

Impaired activity of phagocytic cells in Candida albicans infection after exposure to chronic varied stress.

OBJECTIVE: Candidiasis is a prototypic opportunistic fungal disease that may follow severe modulations of the immune system of the host. The purpose of this study was to evaluate which innate immune mechanisms involved in the protection against fungal invasion are impaired under stress conditions. METHODS: Wistar rats were infected intraperitoneally with Candida albicans and immediately exposed to chronic varied stress (CVS) over 10 days (CVS; Ca-S); the fungal burden (CFU), histopathological lesion and ACTH levels were evaluated. Additionally, functional assessment of peritoneal cells (PC) included the phagocytic and anticandidacidal activities and the production of H(2)O(2) and NO. RESULTS: In the only infected animals (Ca), C. albicans colonization stimulated an efficient inflammatory response, while in Ca-S rats poor tissue reactions were associated with increased CFU in livers and kidneys (p < 0.05, Ca vs. Ca-S). Whereas the phagocytic process was not modified, the candidacidal activity of PC was significantly decreased after the application of CVS (p < 0.001, Ca vs. Ca-S). The H(2)O(2) production by macrophages and neutrophils was downregulated by the infection, and while at early intervals these cells possessed a residual oxidative capacity, by day 10, the production of this metabolite was blocked. Spontaneous NO production by macrophages was significantly increased in both Ca and Ca-S animals (p < 0.001), but in stressed rats, this reactive nitrogen intermediate was noticeably downregulated (p < 0.05, Ca vs. Ca-S). The hyperactivity of hypothalamus-pituitary-adrenal axis after exposure to stress was confirmed by an increase in baseline plasma ACTH levels. CONCLUSION: These results show that during infection with C. albicans, the exposure to CVS contributes to the spread of the fungus and downregulates critical functions of phagocytic cells involved in the control of this opportunistic pathogen.

Adrenocorticotropic Hormone↗
PubMed2001

[The cells of accessory immune system].

In the Reticulo-Endothelial System (RES), named at present Accessory Immune System (AIS), two chief groups of cells can be recognized: 1--Antigen-presenting cells: Dendritic cells 2--Antigen-processing cells: Macrophages (or Histiocytic cell) True malignant Langerhans cell neoplasm has not been yet clearly demonstrated. Finally, it is important to note that marcrophages and dentritic cells are commonly observed as relative cells in numerous malignant tumors (carcinomas, sarcomas, lymphomas, etc) However, their precise role has yet to be determined.

Animals↗
PubMed1999

[Comparative structural study of the glial blastomas of the central nervous system].

The objective of our work is to compare 2 diagnostics methods and demonstrate the similarities of the different Central Nervous System Glial Tumor Classifications. Immuno-marking techniques for gliofibrilar acid protein (GFAP), and special silver impregnations to compare the results according to the last histogenetic interpretations were used. 95 Gliomas were studied with hematoxiline-eosine and silver techniques, and in 58 randomized selected cases the technique for GFAP was also used. Both methods showed the same results in the diagnosis of Glial Tumors whose cells possess gliofibrils: Glioepitelioma (Ependymoma), Glioblastoma, Astroblastoma, and Astrocytoma. In the Oligodendrioglomas whose cells possess microtubules but not gliofibrils, the silver techniques marked these cells and their prolongations while the technique for GFAP did not. Regarding Gliomas, there are similarities by comparing the Del Río Ortega-Polak classification with those of the WHO and other authors. There are differences only in the "names" of some tumors or in their histogenetic interpretation, which are not substantial and are confined to the "Polar Espongioblastoma" and "Gliosarcoma". Therefore, we think that the recognition of the Del Río Hortega-Polak classification is justified.

Brain Neoplasms↗
PubMed1999

[Tumors with rhabdomyoblasts and neuroblasts].

A metallic impregnation technique, Del Río Hortega's double impregnation, to evidence neuroblasts and rhabdomyoblasts, with recommendations as to the times of impregnation to obtains better results is evaluated. The images obtained are highly demonstrative both of the embryo elements of the primitive mesenchyma from myoblast, myotube, a rhabdomyoblastic ribbon cell with transverse streaks to the neoplastic elements of this lineage and to the neuroblasts with their extensions. The study material includes a renal tumor of Wilms with rhabdomyoblasts and neuroblasts and a cerebellum neuroblastoma with a rhabdomyoblastic element. These injuries are considered dysembryoplasic. We also studied two botryoid embryo rhabdomyosarcomas, begin one or them unusually found in a menopausic woman, two Müller mixed tumors of the uterus and Fallopian tubes, a rhabdomyoma in pharynx and three human embryos from aborted material between 5 and 13 weeks old. We emphasize the use of double impregnation to study rhabdomyoblasts and neuroblasts. In rhabdomyosarcomas, structures and elements similar to those of the embryo stage--racketoid and ribbon cells, myotubes and rhabdomyoblasts--can be observed. The tumor of Wilms is a dysembryoplasic tumor composed of renal blastem where we have found rhabdomyoblasts and neuroblasts. In the cerebellum neuroblastoma we observe rhabdomyoblasts with certain organism (ectomesenchyma). Finally, we describe a rather infrequent case of a cervix botryoid rhabdomyosarcoma of a menopausic woman.

Adolescent↗
PubMed1998

Fasciola hepatica-induced immune suppression of spleen mononuclear cell proliferation: role of nitric oxide.

The aim of the present study was to evaluate the proliferative response of spleen mononuclear cells (Spm) to mitogens in rats infected with Fasciola hepatica and its correlation with Spm and peritoneal cell (PC) nitric oxide (NO) production on Days 1, 3, 7, 14, 30, and 60 postinfection. In addition, histological changes in the liver were also studied. The proliferative response to Con A of F. hepatica-infected Spm was significantly decreased on Day 7 postinfection (P < 0.01). However, a pronounced increase of the proliferative response was detected from Day 3 until Day 60 when Spm were stimulated with LPS. In order to determine whether NO levels were modified during F. hepatica infections, we quantified nitrite in Spm and PC supernatants in cultures. Our results indicate a profound decrease of nitrite production by LPS-stimulated PC on the first and second weeks postinfection, and an increase in the levels of this mediator on LPS-stimulated Spm at the same postinfection time. The F. hepatica excretory-secretory antigen (ESA) was in part involved in the decrease of nitrite production by LPS-stimulated PC. A mechanism to avoid an immune response during the first stages of liver penetration could explain the transient suppression observed in Spm proliferative responses. On the other hand, the decrease in NO production by rat-infected PC could also be one of the strategies of the parasite to avoid the potential killing effect of NO during peritoneal migration.

Animals↗
PubMed1993

Long-term enalapril and hydrochlorothiazide in radiation nephritis.

Radiation of the kidney often leads to renal failure. The contribution of arterial hypertension to the development of this complication is unclear. The aim of this study was to determine the renal effects of antihypertensive therapy in 1- and 2-kidney rat models of radiation nephritis. Five groups of Long Evans rats had X-irradiation of the left kidney. In groups 1 and 2, the right kidney was left undisturbed (2-kidney model). The rats in group 3, 4 and 5 underwent right nephrectomy 21 days before radiation (1-kidney model). Groups 1 and 3 received no drug treatment and served as controls for each model. Groups 2 and 4 had enalapril 50 mg/l in drinking water and group 5 hydrochlorothiazide (HCT) 200 mg/l, also in drinking water. Blood pressure increased significantly in both control groups and remained normal throughout the study in all treated groups. At the end of the study, mean urinary protein excretion was lower in the two enalapril-treated groups but not in HCT-treated animals. Groups 1 and 2 (2-kidney models) showed similar increments in plasma creatinine (PCreat), and, in both groups, the creatinine clearance (CCreat) dropped to the same extent. Among nephrectomized animals (1-kidney model), PCreat was lower and CCreat higher in the enalapril-treated group. Consistent with these findings, glomerular sclerosis was less severe in both enalapril-treated groups. We conclude that, in radiation nephritis, lowering blood pressure with enalapril exerts a beneficial effect on renal function and structure, whereas a similar reduction in blood pressure induced by HCT does not.

Animals↗
PubMed1990

Mechanisms of hypertension in renal radiation.

This study was undertaken to investigate the role played by renal functional and structural changes in the development of radiation-induced hypertension. Four groups of rats were studied: 1) left kidney radiated, 2) sham procedure, 3) uninephrectomy followed 3 weeks later by radiation of the contralateral kidney, and 4) uninephrectomy followed by sham procedure 3 weeks later. All radiated rats became hypertensive at 12 weeks (p less than 0.05) and had higher protein excretion (p less than 0.05). In the presence of an intact contralateral kidney, radiation causes mild-to-moderate histological abnormalities, and therefore, creatinine clearance and water and sodium handling do not change. Plasma renin activity increased in this group (p less than 0.05). Radiated uninephrectomized rats showed decreased creatinine clearance (p less than 0.05), but renin activity remained unchanged. These rats developed severe histological abnormalities in glomeruli, interstitia, tubuli, and vessels resulting in increased sodium and water output. The average of individual tubular and interstitial scores correlated significantly with both water intake and output but not with sodium excretion. These studies suggest that in the presence of an intact kidney, renin is an important determinant in the development or maintenance of radiation hypertension, whereas in the absence of the contralateral kidney, severe histological changes and renal failure are prominent despite increased water intake and output. The more severe glomerular sclerosis and proteinuria in the latter model could be related to diminished renal mass.

Animals↗
PubMed1982

[Mixed tumors of the salivary and cutaneous glands. Studied by silver technics].

The authors study salivary and cutaneous mixed tumors in a comparative way. They use silver impregnation techniques, specially those developed in spanish and argentine schools. As a result, they obtain a morphological richness using those techniques. One of these, specially Del Rio Hortega-Polak allow to document the preponderant role of the myoepithelial cells in the genesis of these tumors.

Adenoma↗