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Biomedical subjects

A Maleci

Publications and source records attributed to A Maleci.

At least 37 records · Page 2Linked to original sources
PubMed1991

Cell mediated cytotoxicity and cytokine production in peripheral blood mononuclear cells of glioma patients.

A mannoprotein preparation (MP) from Candida albicans induced MHC-unrestricted cytotoxicity in peripheral blood mononuclear cells (PBMC) from healthy subjects, but not in those from glioma-bearing subjects. The two groups of subjects did not significantly differ in the number of cells bearing typical natural killer (NK) markers (both in resting and MP stimulated PBMC) and NK activity. However, interferon gamma (IFN-gamma) production was in tumour patients minimal or significantly reduced, as compared to healthy subjects, following PBMC stimulation by MP or phytohaemoagglutinin, respectively. In addition, minimal, if any, stimulation of interleukin-2 (IL-2) production was achieved in MP stimulated PBMC from glioma patients. Considering the pivotal role of the above cytokines in immune responses, particularly in those concerning generation of antitumour effectors, our results consistently suggest that defective cytokine production is one possible mechanism of immunological impairment in glioma patients. They also provide indirect support for a possible clinical use of IFN-gamma as an immunopotentiating agent in gliomatous subjects.

Adult↗
PubMed1990

Effect of phorbol esters on the susceptibility of a glioma cell line to lymphokine-activated killer cell activity.

The mechanisms by which lymphokine-activated killer (LAK) cells exert their cytotoxic effects are not well understood. This study demonstrates that phorbol ester pretreatment of a LAK cell-sensitive glioma cell line (SNB-19) induced a significant decrease in the susceptibility of cells to LAK cell-mediated lysis. This effect was produced by low concentrations of the tumor-promoting phorbol ester, phorbol-12,13-myristate acetate (PMA), and was reversible. Protein kinase C (PKC) inhibitors failed to block this phenomenon. No apparent alteration in the ability of LAK cells to bind to their targets was observed. Thus, PMA may have exerted its effects by a mechanism that does not require PKC, or these glioma cells may possess an isozyme of PKC which is insensitive to the inhibitors used in these studies.

Cell Division↗
PubMed1989

Malignant monstrocellular brain tumours. A study of 42 surgically treated cases.

A series of 42 cases of monstrocellular brain tumour (MBT) who received surgery over a 34 year period is reviewed with the aim of gaining more understanding of the biology of this oncotype. A case of benign pleomorphic xanthoastrocytoma was identified among the cases and is discussed in another paper. In this series, as in most others taken from the literature, MBTs were more frequent in young subjects (55% were under 50 years of age and 17% were children) and presented as a superficially located (63%), often sharply circumscribed (42%) mass. The mean survival time for 24 patients treated by surgery and radiotherapy (RT) was 57 weeks compared to 32 weeks for 12 treated by surgery alone (p less than 0.02). Patients younger and older than 50 years showed the same survival and the slightly better course of children did not reach statistical significance. Besides postoperative RT, the only other factor that showed a significantly positive influence on survival was the presence of a definite lymphocytic infiltration (LI) in the tumour (p less than 0.05). This result confirms our previous study on the prognostic influence of LI in glioblastoma (GB). Actually, we noted that the prolonged survival of both MBT and GB patients exhibiting a definite LI (67% and 11.5%, respectively, in the two series) was strikingly similar. We conclude that MBT is a peculiar oncotype with a probably better prognosis than GB in the majority of cases. Lymphocytes seem to play a major prognostic role and giant-monstrous cells are indirectly implicated, reasonably enhancing the host's immune response by magnifying the antigenic stimulus.

Adolescent↗
PubMed1988

The response of peripheral blood mononuclear cells of glioma-bearing patients to stimulation with microbial antigen and IL-2: proliferation and IFN-gamma production.

Peripheral blood mononuclear cells (PBMC) of malignant glioma-bearing patients were stimulated in vitro with a glucomannan-protein antigen of Candida albicans (GMP) or Interleukin-2 (IL-2), then assayed for proliferation and production of Interferon gamma. PBMC of healthy, age and sex matched subjects were the controls. PBMC from glioma-bearing patients did not differ, as a whole, from PBMC of healthy donors in IL-2 or GMP-induced proliferation. However, they showed a definitely lesser ability to produce IFN. The results are discussed in the framework of the impairment of immune responses known to affect glioma-bearing patients.

Antigens, Fungal↗
PubMed1988

Cell-mediated cytotoxicity in glioma-bearing patients: differential responses of peripheral blood mononuclear cells to stimulation with interleukin-2 and microbial antigen.

Peripheral blood mononuclear cells (PBMC) of malignant glioma-bearing patients were stimulated in vitro with Interleukin-2 (IL-2) or a glucomannan-protein antigen of Candida albicans (GMP) then assayed for proliferation, production of IFN-gamma, and generation of cytotoxic effectors against either K562 tumor cell line or freshly-cultured allogenic glioma cells. PBMC of healthy, age and sex-matched subjects were the controls. PBMC of glioma-bearing patients did not differ, as a whole, from PBMC of healthy donors in IL-2 or GMP-induced proliferation. However, they showed a lesser ability to produce IFN as well as a substantial inability to generate cytotoxic effectors following GMP stimulation. PBMC of glioma patients were fully responsive to IL-2 in cytotoxicity generation, as were the PBMC from normal subjects. The results suggest that glioma patients may have a defective antigen-mediated activation of natural cytotoxic effectors. This hyporesponsiveness is not accompanied by depressed lymphoproliferation and does not apparently involve a reduced response to IL-2.

Adult↗
PubMed1988

Post-radiation glioma in a child. Case report and review of the literature.

A case of primary brain neoplasm is reported that developed 11 years after prophylactic brain irradiation and intrathecal methotrexate (MTX) given for acute lymphocytic leukemia (ALL) at the age of 3 years. Cases of supposed postirradiation gliomas in children seem to have increased in recent years, particularly following apparently successful treatment for ALL or medulloblastoma. This increase might reflect the increased number of long-surviving cancer children and thus suggest that brain irradiation may be a potential risk factor in this population. After reviewing some general data on neurooncogenesis, two points are stressed: (1) the child's brain is particularly susceptible to the mutagenic effects of ionizing radiation owing to physiologically active postnatal glial cell proliferation, which takes place in the cerebral hemispheres, especially during myelinogenesis; (2) MTX could promote glial neoplasm by enhancing reparative glial cell proliferation. Prospective studies seem necessary to show whether or not prophylactic brain radiation in ALL plays an oncogenetic role. Nevertheless, besides recurrent leukemia, leukoencephalopathy, and radionecrosis, the remote possibility of radiation-induced glial neoplasms should always be considered in cases of children treated for leukemia who present with neurological complications.

Adolescent↗
PubMed1987

Immunocomplexes in rat and rabbit spinal cord after injury.

The possibility that, following a major lesion of the central nervous system, a humoral immune response could be evoked with formation of immune complexes "in situ" was investigated. For this purpose, an immunohistochemical study on rabbit and rat spinal cord at different times after surgical transection was carried out. The peroxidase-antiperoxidase method showed IgG decoration of the myelin sheaths starting a short time after surgery. The sera of intact and injured animals were then tested both by immunohistochemical methods on intact spinal cord sections and by immunoelectrophoresis on a protein extract of homologous spinal cord. The results showed in the rabbit the absence of antibodies to neural antigens before surgical injury and its appearance within a few days after surgery. On the other hand, in the rat, even before the injury, we found antibodies to neural tissue which decreased in the first few hours after injury, and returned to control values during successive days. The same experiments were conducted after a peripheral nerve lesion (sciatic nerve crush), but no immune response could be detected. The possible role of this immune response in the failure of axonal regeneration in mammalian spinal cord is briefly discussed.

Animals↗
PubMed1987

Pharmacokinetics of recombinant interferon-alpha 2 following intralesional administration in malignant glioma patients.

Pharmacokinetics of recombinant interferon-alpha 2 (rIFN-alpha 2) following intralesional administration into patients with malignant gliomas was investigated. A dose of 5 X 10(6) IU of rIFN-alpha 2 was injected locally postoperatively for 2 weeks each day, and the same dose was then given once a week for 10 additional weeks. During the daily and weekly administration, the IFN was consistently present in the fluid of the postsurgical cavity. Not until 5 weeks after the end of the IFN administration was the IFN undetectable. The decay of IFN injected was minimal.

Adult↗
PubMed1986

Prostaglandin E2 as an immunomodulating factor released in vitro by human glioma cells.

Cultured human glioma cells were found to produce soluble factors that can modulate the in vitro proliferative response of purified T lymphocytes stimulated by phytohemagglutinin (PHA). Neoplastic tissue was removed during surgery for brain glial tumors and cultured in vitro. The glial nature of the neoplastic cells was verified by means of anti-glial fibrillary acidic protein immunohistochemical staining. Serum-free supernatants from these cultures proved capable of suppressing in vitro proliferation of PHA-stimulated T lymphocytes. Suppression was reduced when indomethacin or aspirin was added to the culture medium. Thin-layer chromatography revealed the presence of prostaglandins and other arachidonic acid derivatives in the supernatants. The radioimmunoassay used to quantify the prostaglandin E2 (PGE2) in the supernatants showed detectable amounts of PGE2, which disappeared after the cultures had been treated with anti-inflammatory drugs. These data support the hypothesis that tumoral glial cells can play a role in the host immune response in the central nervous system, namely by producing soluble factors.

Antibody Formation↗
PubMed1985

Pleomorphic xanthoastrocytoma with 18-year survival. Case report.

The authors present a case of right parietal pleomorphic xanthoastrocytoma that occurred in a 24-year-old man. The patient was originally operated on in 1966, and at that time the diagnosis of monstrocellular sarcoma was made. The patient is still alive and totally symptom-free. A careful reevaluation of the microscopic findings, including positive glial fibrillary acidic protein staining, led to the definite diagnosis of pleomorphic xanthoastrocytoma.

Adult↗
PubMed1983

Histopathological and ultrastructural study of a case of infantile metachromatic leukodystrophy.

The histopathological and ultrastructural findings on a nerve biopsy specimen and on a CNS necropsy specimen in a case of IML with a typical clinicaL course are reported. Nerve biopsy once again proved to be a sure diagnostic guide even at an early stage of the disease. Some differences in the fine structure of the cytosomes between the nerve biopsy and CNS necropsy material studied four years later may be due to the different rates of catabolism of the constituent lipids as well as to post mortem artefacts.

Brain↗
PubMedDate not supplied

Role of autocrine stimulation in a glioma cell line.

It has recently been shown that autocrine stimulation can play a pivotal role in the development and progression of a variety of neoplasms, including malignant gliomas. In this paper is reported how a glioma cell is able to be stimulated by basic fibroblast growth factor (bFGF) and, at the same time, to produce a growth factor which shares with bFGF many biological and biochemical properties.

Cell Division↗
PubMedDate not supplied

Immunotherapy of malignant gliomas.

Some recent immunological approaches to therapy of cancer are briefly considered. The possibility of the application of immunotherapy to malignant gliomas was investigated in vitro, evaluating the cytotoxic activity of Interleukin-2-activated lymphocytes against cultured human glioma cells. The possibility of generating valid cytotoxic effectors from glioma patients peripheral blood was also investigated in consideration of the immunological alterations reported in such patients.

Brain Neoplasms↗
PubMedDate not supplied

[Multicentric glioma: presentation of a case].

A case of multiformis glioblastoma with a parieto-temporal and brainstem localization is presented. Multicentric gliomas are unfrequently reported in the literature, and very often rise diagnostic problems with other multiple lesions of the Central Nervous System, either of neoplastic nature or not. After briefly reviewing the pathogenetic hypothesis concerning this lesion, indication and limits of clinical and radiological investigations are discussed.

Adult↗