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R Moumdjian

Publications and source records attributed to R Moumdjian.

10 recordsLinked to original sources
PubMed2001

Expression of multidrug-resistance P-glycoprotein (MDR1) in human brain tumors.

Multidrug resistance (MDR) is associated with the expression of P-glycoprotein (P-gp), an ATP-dependent transporter which expels anti-cancer drugs from cells. In the present study, MDR1 P-gp was immunodetected by Western blot analysis in 60 human brain tumors, including meningiomas, schwannomas, low-grade gliomas (astrocytomas, pilocytic astrocytomas) and high-grade gliomas (anaplastic astrocytomas, glioblastomas and anaplastic oligodendrogliomas). Most samples from primary tumors expressed P-gp at the same levels as normal brain tissue except for schwannomas, in which levels were reduced by 65%, and meningiomas, in which levels were more than 10-fold higher in 7 of 10 samples. P-gp levels were 70% and 95% lower in brain metastases from melanomas and lung adenocarcinomas, respectively, than in normal brain tissue. These results indicate that the majority of primary brain tumors express MDR1 P-gp and that its high expression levels in meningiomas may be a marker for this type of brain tumor.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2001

Scalp nerve blocks decrease the severity of pain after craniotomy.

UNLABELLED: Up to 80% of patients report moderate to severe pain after craniotomy. In this study, we assessed the efficacy of scalp block for decreasing postoperative pain in brain surgery. Thirty patients scheduled for supratentorial craniotomy were enrolled. They were randomly divided into two groups: Ropivacaine (scalp block with 20 mL of ropivacaine 0.75%) and Saline (scalp block with 20 mL of saline 0.9%). Anesthesia was standardized. The scalp block was performed after skin closure and before awakening. Postoperative pain was assessed at 4, 8, 12, 16, 20, 24, and 48 h by using a 10-cm visual analog scale. Analgesia was provided with sub- cutaneous codeine as requested by the patient. Average visual analog scale scores were higher in the Saline group as compared with Ropivacaine (3.7 +/- 2.4 vs 2.0 +/- 1.6; P = 0.036). The total dose of codeine did not differ, nor did the duration of time before the first dose of codeine was required in the Ropivacaine (571 +/- 765 min) versus Saline (319 +/- 409 min; P = 0.17) group. In conclusion, we found that postoperative scalp block decreases the severity of pain after craniotomy and that this effect is long lasting, possibly through a preemptive mechanism. IMPLICATIONS: Up to 80% of patients report moderate to severe pain after craniotomy. This randomized double-blinded study demonstrated that ropivacaine scalp block decreases the severity of pain after supratentorial craniotomy.

Adolescent↗
PubMed1999

Expression of matrix metalloproteinases and their inhibitors in human brain tumors.

Sixty human brain tumors, classified according to the New World Health Organization (WHO) classification including, grade I schwannomas, meningiomas and pilocytic astrocytomas, grade II astrocytomas, grade III anaplastic astrocytomas, grade IV glioblastomas, grade III anaplastic oligodendrogliomas and grade IV glioblastomas and lung and melanoma metastases were analyzed for the expression of three matrix metalloproteinases (MMPs), two tissue inhibitors of MMPs (TIMPs) and for MMP activity. Some correlation was found between MMP expression and the degree of malignancy. Western blotting analysis revealed a more uniform pattern of distribution of MMP-2 (gelatinase A) than of MMP-9 (gelatinase B) and MMP-12 (metalloelastase) among tumors. MMP-9 levels were found to be significantly higher in grade III anaplastic astrocytomas and anaplastic oligodendrogliomas than those in grade I schwannomas and meningiomas. Anaplastic astrocytomas and Grade IV glioblastomas expressed significantly higher levels MMP-12 than grade I meningiomas. All sixty tumors showed a similar pattern of activity in zymography, proMMP-9 being the major species detected. Interestingly, TIMP-1 and TIMP-2 expression levels were especially low in tumors of grade II and grade III but significantly higher in tumors of grade I, particularly in schwannomas. Taken together, these data suggest that: 1) a balance between MMPs and TIMPs has an important role to play in human brain tumors; 2) TIMP expression may be valuable markers for tumor malignancy.

Astrocytoma↗
PubMed1999

Expression of matrix metalloproteinases and their inhibitors in human brain tumors.

Sixty human brain tumors, including grade I meningiomas, schwannomas, and pilocytic astrocytomas, grade II astrocytomas, grade III anaplastic astrocytomas and oligodendrogliomas, and grade IV glioblastomas and lung and melanoma metastases were analyzed for expression of four matrix metalloproteinases (MMPs), two tissue inhibitors of MMPs (TIMPs), and MMP activity. No marked correlation was found between MMP expression and the degree of malignancy. Western blotting analysis revealed a more uniform pattern of distribution of MMP-2 (gelatinase A) than of MMP-9 (gelatinase B) and MMP-12 (metalloelastase) among tumors. All 60 tumors showed a similar pattern of activity in zymography, MMP-2 being the major species detected. Interestingly, TIMP-1 and TIMP-2 expression levels were low in tumors of grade III but significantly higher in tumors of grade I, particularly schwannomas. Altogether, these data suggest that: (1) the balance between MMP-2 and TIMP-2 is important in human brain tumors; and (2) TIMP expression may be a valuable marker for tumor malignancy.

Blotting, Western↗
PubMed1997

Endovascular treatment of acutely ruptured and unruptured aneurysms of the basilar bifurcation.

The surgical treatment of basilar bifurcation aneurysms is difficult and the need for an alternative approach is frequently stated. To assess the efficacy and safety of endovascular treatment of aneurysms located at the basilar bifurcation, the authors prospectively studied angiographic results, clinical results, and complications in 31 patients treated with Guglielmi detachable coils (GDCs). Patients treated acutely after subarachnoid hemorrhage (SAH) were graded according to the Hunt and Hess classification and clinical outcome was determined at 1- and 6-month intervals according to the Glasgow Outcome Scale (GOS). There were 18 women and 13 men, ranging in age from 34 to 67 years (mean age 48 years). Twenty-three were treated acutely after SAH. Clinical Hunt and Hess grades at presentation were as follows: Grade I, six patients; Grade II, three; Grade III, 11; Grade IV, two; and Grade V, one. The GOS score for the group of patients treated acutely was: GOS I, 18 patients; GOS II, III, and IV, one patient each; and GOS V, two patients. There were seven technical complications in this group, most often asymptomatic, but one patient died after aneurysm rupture during treatment and one had residual diplopia at 4 months. Eight patients were treated for incidental basilar bifurcation aneurysms. One technical complication with no neurological deficit occurred in this group of patients with incidental aneurysms. Immediate angiographic results were considered to be satisfactory in 94% of patients, with complete obliteration in 42% and residual neck and dog ears in 52%. There was no bleeding episode after treatment during clinical follow-up periods ranging from 3 to 42 months (mean 15.5 months in 29 surviving patients). Angiographic results were available for 27 patients at 6 months and were as follows: 30% of the lesions were completely obliterated, 59% presented some residual neck, and 11% showed some opacification of the aneurysm sac. During the follow-up period of up to 42 months, a total of seven recurrences were noted, necessitating retreatment with GDCs in five patients. Endovascular treatment of basilar bifurcation aneurysms prevented rebleeding and could be performed without clinically significant complications in 94% of patients. Clinical results after SAH compared favorably with surgical series. Morphological results appear less satisfactory, and long-term angiographic follow-up review is mandatory to detect recurrences.

Adult↗
PubMed1997

Endovascular treatment of ophthalmic segment aneurysms with Guglielmi detachable coils.

PURPOSE: To evaluate the safety and efficacy of endovascular treatment of ophthalmic segment aneurysms with Guglielmi detachable coils (GDCs), as well as the primary indications for such treatment. METHODS: We conducted a prospective study of 26 patients with 28 aneurysms of the ophthalmic segment in whom treatment with GDCs was attempted. Anatomic results were measured by statistical analysis of variance for such factors as age, sex, presence of subarachnoid hemorrhage, anatomic type (ophthalmic or superior hypophyseal), size of aneurysmal sac, and width of aneurysmal neck. Clinical evaluation and control angiography were performed at 6 and 18 months. RESULTS: Overall, complete occlusion was obtained in 14 aneurysms (50%) and small residual necks were left in 11 aneurysms (39%). Three treatment attempts failed (11%). Complete occlusion was obtained in 76% of small-necked aneurysms as opposed to 9% of aneurysms with a large neck. The best predictor of anatomic result was the size of the aneurysmal neck. Complete occlusion was obtained in 85% of superior hypophyseal aneurysms of the paraclinoid variant. One permanent complication was related to treatment. CONCLUSION: Endovascular treatment with GDCs appears to be a safe and efficient alternative approach for ophthalmic segment aneurysms, especially for paraclinoid variants of superior hypophyseal aneurysms, which tend to have a small neck.

Adult↗
PubMed1991

Gamma-interferon promotes proliferation of adult human astrocytes in vitro and reactive gliosis in the adult mouse brain in vivo.

Reactive gliosis is a characteristic response of astrocytes to inflammation and trauma of the central nervous system. To investigate whether soluble factors (cytokines) from inflammatory mononuclear cells that accumulate at lesion sites can provide the cellular signals to initiate gliosis and to identify such cytokines, we have tested and found that supernatants derived from subsets of activated human T lymphocytes (CD8+ or CD4+) are potent mitogens for cultured human adult astrocytes. This effect is blocked by a neutralizing antibody to gamma-interferon (IFN). Recombinant IFN alone can induce proliferation of human adult astrocytes in vitro and increase the extent of trauma-initiated gliosis in the adult mouse brain. The astrocyte proliferation-inducing activity of supernatants of glial cultures treated with IFN can be completely blocked with IFN-neutralizing antibody, suggesting that the proliferative effect does not require intermediary cytokines or cells. These results implicate IFN as an important mediator of the gliosis observed in pathologic conditions of the adult central nervous system associated with infiltrating lymphocytes.

Animals↗
PubMedDate not supplied

Intracerebral gangliogliomas in patients with partial complex seizures: CT and MR imaging findings.

The clinical and radiologic findings in 19 patients with partial complex seizures and surgically proved intracerebral gangliogliomas were reviewed to characterize the radiologic features of these lesions. The CT and MR findings were not specific. On CT the gangliogliomas can be hypodense with no enhancement and they often have calcifications. On MR these tumors have a wide variety of signals. In five of our cases the tumor had a high-intensity signal with a cystlike component on proton density- and T2-weighted images. In five cases the lesion had an inhomogeneously intense signal on proton density-weighted images and high signal intensity on T2-weighted images. The tumor had high-intensity signal on both proton density- and T2-weighted images in four patients. Finally, in two cases the MR findings were normal. We recommend MR as the examination of choice for patients with partial complex seizures because it allows an artifact-free evaluation of the temporal region. However, CT should also be performed in order to recognize calcifications that may be missed on the MR examination.

Adolescent↗