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S Fenu

Publications and source records attributed to S Fenu.

At least 55 records · Page 3Linked to original sources
PubMed1992

Blockade of N-methyl-D-aspartate receptors potentiates dopaminergic responses in the 6-OHDA model of Parkinson: differential role of D-1 and D-2 receptors.

The non competitive antagonist of N-methyl-D-aspartate (NMDA) receptors MK-801, at doses which did not produce any behavioural modification per se, increased by about 40% the contralateral turning induced by the dopaminergic (DA) D-1/D-2 agonist L-dopa in rats bearing a unilateral lesion of the DA nigro striatal neurons. Administration of MK-801 in combination with selective agonists of the D-1 (SKF 38393) or D-2 (LY 171555) receptor, induced an increase of about 280% of D-1 mediated turning and a 70% decrease of D-2 mediated turning. Analysis of the potentiation of L-dopa mediated turning by MK-801 after selective D-1 receptor blockade by SCH 23390, revealed that the increase of turning was related to the stimulation of D-1 receptors by L-dopa. Immunocytochemical visualization of the proto-oncogene c-fos in the caudate-putamen (CPu) of lesioned rats, revealed a sparse c-fos positive nuclei in the lesioned CPu of rats treated with SKF 38393 alone, while after combined administration of MK-801 and SKF 38393 dense labelling of nuclei was found. The results indicate that blockade of NMDA receptors by MK-801 acts synergistically with D-1 agonists in the induction of turning after DA denervation and shows that these changes are correlated with c-fos induction in specific areas of the CPu.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1992

Opposite effects of NMDA receptor blockade on dopaminergic D1- and D2-mediated behavior in the 6-hydroxydopamine model of turning: relationship with c-fos expression.

In rats with unilateral 6-hydroxydopamine (6-OHDA) lesions of the nigrostriatal dopaminergic pathway, I-dihydroxyphenylalanine (L-DOPA) induces contralateral turning through activation of denervated D1 and D2 receptors. Blockade of N-methyl-D-aspartate (NMDA) receptors by the noncompetitive antagonist (+)MK-801 (0.1 mg/kg, i.p.), potentiated L-DOPA-induced contralateral turning. In 6-OHDA lesioned rats, selective agonists of D1 (SKF 38393, CY 208-243) or D2 (LY 171555) receptors also induce contralateral turning; however, (+)MK-801 pretreatment, although markedly potentiating D1, almost completely inhibited D2-mediated turning. The potentiation of SKF 38393-induced contralateral turning by MK-801 was stereospecific and was observed also with the noncompetitive NMDA antagonist phencyclidine, and with the competitive antagonist CPP. Administration of the D1 antagonist SCH 23390 (0.1 mg/kg s.c.) blocked (+)MK-801-induced potentiation of L-DOPA contralateral turning, confirming the D1 nature of the effects observed. Expression of the early gene c-fos in the caudate-putamen (CPu) is known to be activated by stimulation of supersensitive D1 receptors. Immunohistochemical studies on c-fos revealed sparse c-fos positive nuclei in the lesioned CPu after 1.5 mg/kg of SKF 38393, whereas after combined administration of (+)MK-801 and SKF 38393, dense labeling of nuclei was obtained in the dorso-lateral aspect of the CPu. Therefore, blockade of NMDA receptors acts synergistically with D1 and antagonistically with D2 receptor stimulation in the 6-OHDA model of turning, suggesting that different neuronal pathways are involved in the mediation of D1 and D2 responses.

Animals↗
PubMed1991

Positive and negative interactions in the behavioural expression of D1 and D2 receptor stimulation in a model of Parkinsonism: role of priming.

Previous exposure to a dopaminergic agonist (priming) strongly potentiates contralateral turning behaviour in response to D1 and D2 agonists in unilaterally 6-hydroxydopamine-lesioned rats. In order to study the influence of priming on the behavioural interaction of D1 and D2 receptors, we examined the effect of selective D1 and D2 receptor blockade on the contralateral turning induced by the mixed D2/D2 agonist apomorphine in drug-naive and primed 6-hydroxydopamine-lesioned rats. In drug-naive rats, apomorphine induced a dose-related, apparently monophasic rotation curve. Administration of selective D1 (SCH 23390) or D2 (raclopride) antagonists abolished the contralateral turning induced by 0.1 mg/kg of apomorphine and partially inhibited that induced by 0.5 mg/kg. In primed rats low doses of apomorphine (0.05 mg/kg) induced an apparently monophasic contralateral turning which was reduced by D1 receptor blockade and completely abolished by D2 receptor blockade; a higher dose of apomorphine (0.1 mg/kg) instead elicited a biphasic (two-peak) pattern of rotation. After this dose of the agonist, blockade of D1 or D2 receptors abolished the second peak of rotation but, while D1 blockade reduced the total number of turns, D2 blockade failed to do so. Quantitative analysis of the interaction between D1 and D2 receptors in the overall turning effect, as well as in the time-course of turning behaviour, indicates that D1 and D2 receptors interact not only positively but also negatively. After higher doses of apomorphine, both negative and positive interactions take place sequentially during the time-course of apomorphine action and provide a clue for explaining the two-peak pattern of rotation observed after apomorphine in rats previously exposed to the drug.

Animals↗
PubMed1991

Treatment of acute myeloid leukaemia patients with recombinant interleukin 2: a pilot study.

Twelve patients with acute myeloid leukaemia (AML) with evidence of resistant disease were treated with recombinant interleukin 2 (rIL2) given intravenously by continuous infusion. No objective response to rIL2 alone was documented in the seven patients with advanced disease (20-90% resistant blasts in the marrow), except for a partial response to rIL2 plus chemotherapy in one. Of the five patients with limited disease (8-15% marrow blasts), three obtained a complete disappearance of the blasts following two to four 5d courses of rIL2 alone. One patient persists in fourth complete remission (CR) 30 months later, another obtained a third CR for 4 months, and the last remained in third CR for 9 months before relapsing. This latter patient achieved a fourth CR with low-dose cytarabine. The remissions have been maintained with low-dose monthly courses of rIL2 given on an out-patient basis. Two AML did not respond to rIL2 alone; one, however, obtained a fourth CR with chemotherapy and rIL2. Administration of rIL2 was accompanied by organomegaly and leucocytosis, with a frequent lymphocytosis and increase in eosinophils and large granular lymphocytes, both in the blood and in the marrow. Side effects, though often severe, were controllable using a daily dose escalating protocol and never required intensive care treatment. The results of this pilot study indicate that treatment of AML patients with rIL2 is feasible and may result in the disappearance of chemotherapy-resistant blasts in patients with limited but detectable disease. Further controlled trials in AML in CR appear warranted.

Acute Disease↗
PubMed1990

Immunological definition of acute promyelocytic leukemia (FAB M3): a study of 39 cases.

Acute promyelocytic leukemia (FAB-M3) is a distinct entity among acute non-lymphoid leukemias (ANLL) with peculiar morphological, biological, clinical and prognostic features. An atypical form of M3 (M3v) could be confused with other FAB ANLL and therefore the diagnosis of this variant requires ultrastructural analysis and/or cytogenetic study and/or selective gene rearrangement studies. The immunological phenotype of blast cells in 39 APL patients was studied at diagnosis. The diagnosis of M3 FAB type was ascertained in 32 and the diagnosis of M3v in 7 cases. Using a large series of monoclonal antibodies (mAb), the APL blast cells were B and T cell antigens-negative, HLA-DR constantly negative, CD13- and/or CD33-positive, CD9-positive. Among ANLL this phenotype seems to be closely related to APL both in M3 type and M3v subtype. Because the diagnosis of APL (M3 or M3v) is important in order to establish the specific therapeutic approach, the discriminant capacity of the immunological typing to identify M3 and mainly M3v (hypogranular) could be determinant for a "quick" diagnosis.

Adolescent↗
PubMed1989

Substantia nigra as a site of origin of dopamine-dependent motor syndromes induced by stimulation of mu and delta opioid receptors.

Opioid agonists having different affinity for delta and mu receptors were injected bilaterally in the substantia nigra (SN) of rats. The selective agonist of mu receptors N-MePhe3,-D-Pro4 morphiceptin (PLO 17) produced a stereotyped behavior characterized by stereotyped sniffing and gnawing antagonized by the irreversible antagonist of mu receptors beta-funaltrexamine. In contrast, bilateral intranigral injection of the selective delta agonist D-Pen2,D-Pen5 enkephalin (DPDPE) elicited dose-dependent exploratory behavior and rearing but failed to produce gnawing. The behavioral syndrome induced by DPDPE was significantly reduced by the selective delta antagonist ICI 174,864. Naloxine, a non-selective opioid antagonist, antagonized the effects of both compounds. SCH 23390 and haloperidol, two antagonists of dopaminergic D1 and D2 receptors, respectively, blocked the effects of PLO 17 and DPDPE. The results indicate that stimulation of specific opioid receptor types in the SN elicits specific behavioral syndromes and suggest that the SN might be the site of origin of certain items of the behavioral syndrome evoked by systemic opiates. These items might be mediated by activation of dopaminergic neurons of the ventral mesencephalon.

Animals↗
PubMed1989

Time and dose dependence of the 'priming' of the expression of dopamine receptor supersensitivity.

The D-1 receptor agonist, SKF 38393 (2 mg/kg s.c.), failed to elicit contralateral turning when administered to drug-naive rats 17 days after unilateral 6-hydroxydopamine (6-OHDA) lesioning of the medial forebrain bundle, while it elicited intense contralateral turning 90 days post-lesioning. On the other hand the D-1/D-2 receptor agonist, apomorphine (0.1 mg/kg s.c.), induced contralateral turning in drug-naive rats lesioned 14 days earlier and made the administration of SKF 38393 (2 mg/kg s.c.) 3 days later effective to evoke contralateral turning ('priming'). The effectiveness of apomorphine as a primer of SKF 38393-induced turning depended critically on the interval between the administration of the two agonists. Effectiveness was minimal after 3 h and increased after 6-12 h, peaked at 72 h and was reduced after 10 days. The D-2 receptor agonist, LY 171555 (0.2 mg/kg s.c.), was also effective as a primer of SKF 38393-induced contralateral turning and this effect also was dependent upon the interval between priming and SKF 38393 administration. Moreover, priming was dependent on the dose of drug used as primer and on the dose of SKF 38393 used as a challenge. In contrast to SKF 38393, priming was unable to make effective a dose of LY 171555 that was ineffective in drug-naive rats, suggesting that LY 171555 affects D-1-dependent turning to a greater extent than D-2-dependent turning. The results indicate that the priming phenomenon is rather strictly time- and dose-dependent.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1989

CD7 positive acute myeloid leukaemia: a subtype associated with cell immaturity.

Seventeen patients with acute myeloid leukaemia (AML) whose blasts co-expressed the T-cell associated CD7 antibody were identified among 160 consecutive AML cases. Fourteen had FAB defined AML according to morphocytochemical criteria, whereas three patients were classified as 'MO' on the basis of immunophenotype. The incidence of CD7 positively was particularly significant in the less differentiated subtypes M0 and M1 compared with other FAB groups (P less than 0.001). In all cases the myeloid determinants CD13 and/or CD33 were associated with CD7 expression. Other B-lymphoid (CD10, CD19) or T-lymphoid (CD2, surface and cytoplasmic CD3) markers were analysed and found to be negative. Five out of 15 cases examined were TdT+. Clonal rearrangements of the immunoglobulin heavy chain (IgH) and/or T-cell receptor (TcR) beta chain genes were identified in only three out of 13 cases. Among these, one out of five co-expressing TdT showed IgH rearrangement when analysed at the DNA level. Clinical features at presentation and response to induction therapy did not allow us to consider CD7+ AML patients as a distinct subgroup with prognostic significance. Our data indicate that CD7 expression is a common finding in immature AML, being generally found in the absence of other T-cell features. Rather than suggesting the occurrence of 'mixed leukaemia', such cases confirm a broader spectrum of CD7 reactivity and its possible identification of a particular subset of myeloid progenitors.

Antigens, CD7↗
PubMed1988

Treatment of febrile episodes in neutropenic leukemic patients with the antibiotic combinations piperacillin or ceftazidime plus amikacin: results of a randomized study.

Seventy-six consecutive neutropenic patients with hematologic malignancies, admitted to the "Department of Hematology" of Rome between March and September 1986, were randomly assigned to receive either piperacillin (300 mg/kg in four divided doses) or ceftazidime (100 mg/kg in four divided doses) plus amikacin (15 mg/kg in two divided doses) whenever they developed a febrile episode (temperature greater than 38 degrees C thrice over 12 hours, not related to drugs or transfusions, or else temperature greater than 38.5 degrees C). After 72 hours of antibiotic therapy, in case of persistent fever, piperacillin or ceftazidime was added to the ceftazidime + amikacin or piperacillin + amikacin combination, respectively. The antibiotic treatment was, however, modified according to in vitro susceptibility if a positive culture was present. Success without regimen modification was observed in both antibiotic combinations in 52.6% of cases. Considering the empiric cross of antibiotics, the response rate reached 78%. Neither toxicity nor side effects were observed in the reported groups. Considering blood isolates, we observed a greater incidence of gram-positive organisms compared with gram-negatives (28 cases vs 5 cases, 84.7% vs 15.3% respectively). Fungal infections were documented in four cases, two in each group. Even though no statistical difference was found between the two groups as far as patients not responding to the first antibiotic combination are concerned, piperacillin seems to have had more efficacy (twelve patients responding to the addition of piperacillin vs seven patients responding to the addition of ceftazidime). Piperacillin + amikacin seems to be as effective as ceftazidime + amikacin in the empirical therapy of febrile episodes in neutropenic patients.

Adolescent↗
PubMed1988

Prophylaxis and treatment of inflammatory anorectal complications in leukemia.

Forty leukemic patients with inflammatory anorectal complications were examined. Twenty two were affected by acute lymphatic leukemia, 10 by chronic lymphatic leukemia, 6 by acute myelocytic leukemia and 2 by non H lymphoma and chronic myelocytic leukemia, respectively. In all cases surgery was indicated not only to treat the anorectal complication, but mainly to resume the antiblastic chemotherapy discontinued because of the risk of sepsis and to prevent the failure of bone marrow transplantation in patients with chronic myelocytic leukemia. The underlying malignant disease and the altered platelet, white blood cell and neutrophil levels were shown to be the major factors conditioning the surgical treatment. In 2 cases, acute recurrence of the underlying disease and the development of a graft verus host disease have been the cause of death. It is concluded that in patients eligible for bone marrow transplantation or undergoing radio and/or chemotherapy, local and general antinfective prophylaxis is of paramount importance to decrease the risk of inflammatory anorectal complications.

Abscess↗
PubMed1987

Behavioural expression of D-1 receptor supersensitivity depends on previous stimulation of D-2 receptors.

SKF 38393 (2 mg/kg s.c.), a reportedly selective D-1 agonist, failed to induce contralateral turning behaviour in naive rats bearing 12 days old unilateral 6-hydroxydopamine lesions. On the other hand strong contraversive turning in response to SKF 38393 was obtained if rats had been tested 2 or 7 days before with apomorphine (0.1 mg/kg s.c.) or with LY 171555 (0.2 mg/kg s.c.), a selective D-2 receptor agonist. Contraversive turning in response to SKF 38393 was blocked by a low dose (0.05 mg/kg s.c.) of the specific D-1 antagonist SCH 23390. The results indicate that the behavioural expression of D-1 receptor supersensitivity following lesion of dopaminergic neurons depends on previous exposure to a stimulation of D-2 receptors.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1984

Sequential combination of high dose ARA-C (HiDAC) and asparaginase (ASP) for the treatment of advanced acute leukemia and lymphoma.

Thirty patients with advanced acute leukemia and lymphoma were treated with the sequential combination of high dose ARA-C (HiDAC 3 gm/m2 infused i.v. over 3 h at 0, 12, 24, 36 h) and asparaginase (ASP 6.000 IU/m2 i.m. at hour 42). The sequence was given on day 1 and 8 irrespective of the degree of myelosuppression. Of 22 patients with leukemia there was only one who was absolutely refractory to therapy. Complete remission was induced in 3 patients with ANLL (30%) and in 3 with ALL (30%). Three patients became hypoplastic but recovered with blasts and 12 died from infection, complicated by intracranial hemorrhage in 3, during hypoplasia. Of 8 patients with lymphoma, 2 were clearly refractory to therapy, one died from sepsis and the remaining 5 all entered remission (2 CR + 3 PR, 62%). Activity of HiDAC/ASP against CNS disease is suggested by the clinical response seen in patients with overt meningeal or intracerebral involvement. Toxicity associated with HiDAC/ASP was mainly hematologic. All but one patient experienced hypoplasia and severe pancytopenia; documented infections and major hemorrhages occurred in 80 and 20% of patients respectively. We conclude that HiDAC/ASP is a regimen with definite activity against acute leukemia and lymphoma including CNS disease. Alternate treatment schedules should be explored in order to reduce marrow toxicity.

Adolescent↗
PubMedDate not supplied

Motility and oxidative metabolism of normal polymorphonuclear leukocytes in acute non-lymphoid leukemia in complete remission.

Polymorphonuclear leukocytes (PMN) from 11 patients with acute non-lymphoid leukemia (ANLL) in complete remission and off therapy for at least 22 months were studied for their oxidative metabolism and motility. In all patients, PMN motility tests revealed no consistent abnormality, whereas cells from 2 patients showed a selective impairment of oxidative metabolism, as assessed by the low capacity to reduce nitroblue tetrazolium and/or to generate chemiluminescence when stimulated with phorbol myristate acetate. No morphological change was detectable in PMN from these patients. However, the functional alterations appeared related to an early tendency to relapse, as both patients developed an acute phase after 5 and 9 months from testing, respectively. This suggests that abnormal PMN may circulate in ANLL patients in complete remission in spite of a normal differential count and that functional studies may be useful for detecting such a population.

Adolescent↗
PubMedDate not supplied

Granular acute lymphoblastic leukemia in children. "Aieop Cooperative Group for Cytology of Acute Leukemias".

BACKGROUND: Granular acute lymphoblastic leukemia (ALL) is a rare morphological variant of ALL, characterized by cytoplasmic azurophil granules or inclusions, positive for aspecific esterase and acid phosphatase, with heterogeneous features at the ultrastructural level. METHODS: In an attempt to determine whether the presence of granules or inclusions marks a biologically distinct variety of ALL with peculiar clinical features, a prospective morphological review was undertaken of children entering AIEOP protocols for ALL in the period from 1985 to 1989. RESULTS: Of 531 cases examined, 16 (3%) were found to have greater than 1% granular bone marrow blasts, with 7 cases (1.3%) having greater than 10%. The presence of granules or inclusions was associated with the immunophenotype of "common" ALL. There was no clear association with FAB type L1 or L2 nor with particular clinical or hematological findings at presentation. Complete remission was achieved in all cases; one patient died of infection in remission at 3 months and 2 patients relapsed after 12 and 32 months, respectively, while the others are still in remission after a minimum follow-up of 24 months. CONCLUSIONS: In conclusion, granular morphology seems to have no prognostic importance in children ALL.

Acid Phosphatase↗