Biomedical subjects

C Forni

Publications and source records attributed to C Forni.

At least 37 records · Page 2Linked to original sources

PubMed2001

Histologic response of high-grade nonmetastatic osteosarcoma of the extremity to chemotherapy,.

In 510 patients with osteosarcoma of the extremity treated at the authors' institute between March 1983 and June 1995 with different regimens of neoadjuvant chemotherapy, factors that influenced the histologic response were investigated. The rate of total necrosis was not related to the patients' gender, age, site, size of tumor, serum of alkaline phosphatase values, or route of cisplatin administration. The histologic response significantly and independently correlated with the number of drugs administered before surgery and with the histologic subtype of the tumor. According to the number of drugs used, the percentage of total necrosis was 31% for a four-drug regimen, 18% for a three-drug regimen, and only 1.5% for a two-drug regimen. According to the histologic type, the rates of total necrosis were 41% for telangiectatic tumors, 36% for fibroblastic tumors, 15% for osteoblastic tumors, and 3% for chondroblastic tumors. The authors concluded that in neoadjuvant therapy of osteosarcoma, the histologic response to preoperative treatment, which correlates with prognosis, depends on the effectiveness of the chemotherapy regimen and on some features intrinsically inherent to the tumor. These data should be considered when selecting the type of treatment (adjuvant or neoadjuvant) and the combinations of drugs to be used in preoperative treatment of patients with osteosarcoma.

Adolescent↗

PubMed2001

Neoadjuvant chemotherapy for high grade osteosarcoma of the extremities: long-term results for patients treated according to the Rizzoli IOR/OS-3b protocol.

The results of the Rizzoli IOR/OS-3b neoadjuvant protocol for the treatment of osteosarcoma of the extremity are reported. Preoperative chemotherapy consisted of two cycles of high-dose methotrexate (HDMTX i.v.), followed by a combination of cisplatin (CDP i.a.)/ doxorubicin (ADM i.v.). Postoperatively all patients, regardless of the histologic response, received 3 more cycles of MTX, CDP/ADM alternated with 3 cycles of ifosfamide. In the study performed between January and December 1992 43 patients were enrolled and limb salvage was performed in 39 of them (91%). The histologic response to chemotherapy was good (90% or more tumor necrosis) in 24 patients (56%) and poor (less than 90% tumor necrosis) in 19 (44%). With a minimum follow-up of 7 years, 23 pts (53%) remained continuously free of disease, 19 relapsed and one died due to unrelated cause. In spite of the high number of limb salvages performed, only 2 local recurrences were registered. The 7-year event-free survival and overall survival were, respectively, 53% and 68%. The hematopoietic and extrahematopoietic toxicity experienced by the patients during the entire treatment was relatively mild. These long-term results confirm that, with neoadjuvant chemotherapy, it is possible to cure more than 60% of patients with osteosarcoma of the extremities, avoiding amputation in most of them. These results, however, are no better than those achieved in our previous study IOR/OS-3a, in which only poor responder patients received ifosfamide during the postoperative treatment.

Adolescent↗

PubMed2000

Long-term outcome for patients with nonmetastatic osteosarcoma of the extremity treated at the istituto ortopedico rizzoli according to the istituto ortopedico rizzoli/osteosarcoma-2 protocol: an updated report.

PURPOSE: To provide an estimate of long-term prognosis for patients with osteosarcoma of the extremity treated in a single institution with neoadjuvant chemotherapy and observed for at least 10 years. PATIENTS AND METHODS: Patients with nonmetastatic osteosarcoma of the extremity were preoperatively treated with high-dose methotrexate, cisplatin, and doxorubicin (ADM). Postoperatively, good responders (90% or more tumor necrosis) received the same three drugs used before surgery, whereas poor responders (less than 90% tumor necrosis) received ifosfamide and etoposide in addition to those three drugs. RESULTS: For the 164 patients who entered the study between September 1986 and December 1989, surgery was a limb salvage in 136 cases (82%) and a good histologic response was observed in 117 patients (71%). At a follow-up ranging from 10 to 13 years (median, 11.5 years), 101 patients (61%) remained continuously free of disease, 61 relapsed, and two died of ADM-induced cardiotoxicity. There were no differences in prognosis between good and poor responding patients. ADM-induced cardiotoxicity (six patients), male infertility (10 of the 12 assessable patients), and second malignancies (seven patients) were the major complications of chemotherapy. Despite the large number of limb salvages performed, only four local recurrences (2.4%) were registered. CONCLUSION: With an aggressive neoadjuvant chemotherapy, it is possible to cure more than 60% of patients with nonmetastatic osteosarcoma of the extremity and amputation may be avoided in more than 80% of them. Because local or systemic relapses, myocardiopathies, and second malignancies are possible even 5 years or more after the beginning of treatment, a long-term follow-up is recommended for these patients.

Adolescent↗

PubMed2000

Characterization of striatal lesions produced by glutamate uptake alteration: cell death, reactive gliosis, and changes in GLT1 and GADD45 mRNA expression.

This study investigated the time course of the striatal lesions produced by continuous local injection of the glutamate uptake inhibitor, L-trans-pyrrolidine-2,4-dicarboxylate (PDC) at the rate of 25 nmol/h in rats. The extent of the neurodegeneration area (defined as the lesion area) did not significantly vary with the duration of the PDC treatment between 3 and 14 days, but was markedly reduced 3 months after cessation of the 14-day treatment, probably reflecting striatal atrophy. After the 3-day treatment, the lesion zone showed calcium precipitates and marked microglial reaction contrasting with the reduction of astroglial labeling and loss of the glutamate transporter GLT1 mRNA expression; however reactive astrocytes were observed around the lesion. After the 14-day treatment, the lesion zone presented reactive astrocytes and microglia without calcification, and a partial recovery of GLT1 mRNA expression. Interestingly, the growth arrest DNA damage-inducible GADD45 mRNA expression was induced around the lesion after 3 days but inside the lesion after 14 days of treatment. Three months after the 14-day treatment, the astroglial reactivity persisted within the lesion whereas most of the other markers examined tended to normalize. These data suggest that defective glutamate transport induces primary death of neurons and dysfunction of astrocytes. They strongly implicate reactive astrocytes with GLT1 and GADD45 transcripts in preventing secondary neuronal death.

Animals↗

PubMed2000

Granisetron, tropisetron, and ondansetron in the prevention of acute emesis induced by a combination of cisplatin-Adriamycin and by high-dose ifosfamide delivered in multiple-day continuous infusions.

The antiemetic efficacy of granisetron, ondansetron and tropisetron was evaluated in patients treated with cisplatin-Adriamycin (CDP/ADM) and ifosfamide (IFO) by continuous infusion (CI). In all, 90 patients with osteosarcoma were randomly assigned to receive granisetron (2 mg/m2), or ondansetron (5.3 mg/m2), or tropisetron (3.3 mg/m2) plus dexamethasone 8 mg/m2. Chemotherapy consisted of CDP (120 mg/m2, 48-h CI) followed by ADM (75 mg/m2, 24-h CI) and then, in the second cycle, delivered 3 weeks later, IFO 15 g/m2 (120-h CI). Complete protection (CP) from emesis was obtained on 59% of the 717 days of treatment, without significant differences among the three study drugs. A significantly higher rate of CP was obtained during chemotherapy with IFO than with CDP/ ADM (69% vs 44%; P<0.0001). The rate of CP declined from the first to the last day of treatment for both CDP/ADM (61% to 27%, P<0.0001) and IFO (95% to 43%) cycles (P<0.0001). When CDP/ ADM and IFO are delivered on multiple days by CI, granisetron, ondansetron and tropisetron have the same antiemetic efficacy, which declines from the first day onward through successive days.

Acute Disease↗

PubMed2000

Neoadjuvant chemotherapy for Ewing's sarcoma of bone in patients older than thirty-nine years.

The aim of this study was to determine whether the behaviour of Ewing's sarcoma of bone in adult patients is the same as that observed in children and adolescents. We reviewed the clinical features and outcomes of 23 patients over the age of 39 (17 males, 6 females) who had been treated with neoadjuvant chemotherapy between 1983 and 1995 at our institution. The most common primary sites of tumor were the extremities (16 cases); tumor volume was more than 100 ml in 17 patients, and elevated serum LDH levels were found in 6 cases. The local treatment was surgery in 8 cases, surgery plus radiotherapy in 8, and radiotherapy alone in 7 cases. Chemotherapy comprised a 4-drug regimen in 10 patients, while the other 13 patients received 6 drugs. At a follow-up of 8.8 years (3.5-15) 13 patients remained continuously free of disease and 10 relapsed. The 5-year disease-free survival and overall survival rates were 53% and 59%, respectively. Clinical features, dose intensity, and toxicity of chemotherapy, as well as the outcome of these 23 patients were found to be exactly comparable to the findings observed in 327 patients younger than 40 years treated at our institution in the same period, with the same therapy. We conclude that Ewing's sarcoma of bone in adults is no different from that occurring in children, and we therefore recommend the inclusion of all adult patients in multidisciplinary treatment trials of this tumor.

Adult↗

PubMed2000

Prognostic factors in nonmetastatic Ewing's sarcoma of bone treated with adjuvant chemotherapy: analysis of 359 patients at the Istituto Ortopedico Rizzoli.

PURPOSE: The identification of prognostic factors in patients with nonmetastatic Ewing's sarcoma could allow the use of risk-adapted therapeutic strategies of treatment. PATIENTS AND METHODS: Data on 359 patients with nonmetastatic Ewing's sarcoma of bone treated at a single institution between January 1979 and April 1995 were retrospectively considered. The influence of clinical, hematologic, therapeutic, and histologic parameters on event-free survival was assessed. RESULTS: By univariate analysis, the following features were found to be associated with a poor prognosis: male sex (P <.02), age older than 12 years (P <.006), fever (P <.0001), anemia (P <.0025), high serum lactate dehydrogenase (LDH) level (P <.0001), axial location (P <.04), radiation therapy only for local control (P <.009), type of chemotherapy regimen (P <.0001), and poor chemotherapy-induced necrosis (P <.001). After multivariate analysis, the adverse independent prognostic factors were male sex (P <.04), age older than 12 years (P <.001), fever (P <.0002), anemia (P <.02), high serum LDH level (P <.0003), axial location (P <.02), and type of chemotherapy regimen (P <.0003). When the multivariate analysis was restricted to surgically treated patients, the adverse independent prognostic factors were poor chemotherapy-induced necrosis (P <.0001), fever (P <.015), anemia (P <.02), and high serum LDH level (P <.025). CONCLUSION: The prognosis in cases of nonmetastatic Ewing's sarcoma is influenced by many different clinical and hematologic variables, all of which are to be considered when patients are being stratified according to the risk of relapse. In surgically treated patients, the most important prognostic factor is chemotherapy-induced necrosis.

Adolescent↗

PubMed2000

Neoadjuvant chemotherapy for peripheral malignant neuroectodermal tumor of bone: recent experience at the istituto rizzoli.

PURPOSE: The results achieved in 44 patients with nonmetastatic peripheral neuroectodermal tumor (PNET) of bone treated with neoadjuvant chemotherapy are reported. PATIENTS AND METHODS: A six-drug regimen of chemotherapy (vincristine, doxorubicin, dactinomycin, cyclophosphamide, ifosfamide, and etoposide) was administered to all patients. Local treatment consisted of surgery in 20 patients, surgery followed by radiotherapy in 13, and radiotherapy only in 11. RESULTS: At a mean follow-up of 4.5 years (range, 2 to 7 years), 23 patients (52%) remain event-free, 20 have relapsed (45%), and one has died of chemotherapy-related toxicity. The 5-year event-free survival and overall survival were 54.2% and 62.7%, respectively. To assess the prognostic significance of neural differentiation in the family of Ewing's sarcoma, these results have been compared with the outcomes of 138 concomitant patients with typical Ewing's sarcoma (TES) who were treated according to the same protocol. Of these, 103 (75%) remained continuously event-free, 34 (24%) relapsed, and one died of chemotherapy-related toxicity. It follows that PNET patients treated with this chemotherapy regimen have a significantly worse prognosis than typical ES patients (5-year event-free survival, 54.2% v 70.6%, P <.012; 5-year overall survival, 62.7% v 78.3%, P <.002). CONCLUSION: The authors conclude that studies into new adjuvant therapy for Ewing's sarcoma modulated according to risk of relapse should also consider neural differentiation as a risk factor.

Adolescent↗

PubMed1999

Down-regulation of striatin, a neuronal calmodulin-binding protein, impairs rat locomotor activity.

Striatin, an intraneuronal, calmodulin-binding protein addressed to dendrites and spines, is expressed in the motor system, particularly the striatum and motoneurons. Striatin contains a high number of domains mediating protein-protein interactions, suggesting a role within a dendritic Ca(2+)-signaling pathway. Here, we explored the hypothesis of a direct role of striatin in the motor control of behaving rats, by using an antisense strategy based on oligodeoxynucleotides (ODN). Rats were treated by intracerebroventricular infusion of a striatin antisense ODN (A-ODN) or mismatch ODN (M-ODN) delivered by osmotic pumps over 6 days. A significant decrease in the nocturnal locomotor activity of A-ODN-treated rats was observed after 5 days of treatment. Hypomotricity was correlated with a 60% decrease in striatin content of the striata of A-ODN-treated rats sacrificed on day 6. Striatin thus plays a role in the control of motor function. To approach the cellular mechanisms in which striatin is involved, striatin down-regulation was studied in a comparatively simpler model: purified rat spinal motoneurons which retain their polarity in culture. Treatment of cells by the striatin A-ODN resulted in the impairement of the growth of dendrites but not axon. The decrease in dendritic growth paralleled the loss of striatin. This model allows analysis of the molecular basis of striatin function in the dynamic changes occurring in growing dendrites, and offers clues to unravel its function within spines.

Animals↗

PubMed1998

Neoadjuvant chemotherapy for Ewing's sarcoma of bone: no benefit observed after adding ifosfamide and etoposide to vincristine, actinomycin, cyclophosphamide, and doxorubicin in the maintenance phase--results of two sequential studies.

BACKGROUND: Ifosfamide (IF) alone or combined with etoposide (ET) was reported to be effective in the treatment of patients with Ewing's sarcoma who relapsed after treatment with the VACA regimen, which consisted of vincristine (VC), actinomycin (AC), cyclophosphamide (CP), and doxorubicin (AD). The purpose of this article is to report the results achieved in a new neoadjuvant protocol in which IF and ET were added to the conventional VACA regimen and administered to patients with localized disease. METHODS: In this study, eighty-two patients were treated between May 1988 and October 1991. Chemotherapy consisted of two induction cycles of VC/CP/AD followed by alternating cycles of VC/AD/CP, VC/IF/AC, IF/ET, and VC/CP/AC after local treatment. Twenty-two patients (27%) were treated with surgery only, 22 (27%) underwent surgery followed by radiation therapy, and 38 (46%) received radiotherapy only. RESULTS: At a median follow-up of 6.7 years (range, 4-9 years), 43 patients (52%) remained continuously disease free, and 39 relapsed (34 with metastases, 4 with local recurrence and metastases, and 1 with a local recurrence). These results were similar to those obtained at the same institute in a previous neoadjuvant study (March 1983 and April 1988) that included 108 patients treated with the conventional 4-drug regimen. The 5-year disease free and overall survival in the current study were 54% and 59%, respectively, and in the first study were 50% and 56%, respectively. CONCLUSIONS: The comparison of these two sequential studies, although not randomized, referred to homogeneous groups of patients observed at the same institution who were treated by the same medical team. No advantage was observed when IF and ET were added to the VACA regimen.

Adolescent↗

PubMed1998

Osteosarcoma of the extremities with synchronous lung metastases: long-term results in 44 patients treated with neoadjuvant chemotherapy.

Between September 1986 and September 1991, 44 patients with lung metastases originating from an osteosarcoma of an extremity were treated with: primary chemotherapy, simultaneous resection of primary and metastatic lesions (when feasible), and then further chemotherapy. After primary chemotherapy, lung metastases disappeared in 5 patients, whereas in 11 patients they remained surgically unresectable. All 16 patients received local treatment of the primary tumor only. In the remaining 28 patients simultaneous surgical treatment of the primary and the metastatic tumor was performed. The removal of metastatic lesions was complete in 25 and incomplete in 3 patients. With a median follow-up of 8 years (5.5-10.8) all 14 patients who never achieved a tumor-free status died. Of the 30 patients who achieved remission 5 (17%) remained continuously free of disease and 25 developed new metastases, associated with local recurrence in 4 cases. The 5-year overall survival for all 44 patients of the study was 14%, and the 5-year disease-free survival for the 30 patients who reached remission was 17%. These results are significantly worse than those achieved with the same chemotherapy protocol in 144 contemporary patients with localized disease at presentation (73% disease-free and 79% overall survival). We conclude that, despite aggressive chemotherapy which is successful in patients with localized disease, the prognosis remains very poor for patients with osteosarcoma of the extremities with lung metastases at presentation, and justifies the use of novel therapies.

Adolescent↗

PubMed1998

Predictive factors for local recurrence in osteosarcoma: 540 patients with extremity tumors followed for minimum 2.5 years after neoadjuvant chemotherapy.

We investigated predictive factors for local recurrence in 540 patients with non-metastatic osteosarcoma of the extremity treated with surgery and neoadjuvant chemotherapy, between March 1983 and October 1994. The median follow-up was 7.5 (2.5-15) years. Local recurrences developed in 31 (6%) patients after a median time of 2 (0.5-7) years. Local recurrence did not correlate with patients' age and sex, histologic subtype, site and tumor volume, presence of pathologic fracture, chemotherapy regimen and type of surgery. Local recurrence-free survival (LRFS) correlated with the quality of surgical margins and response to chemotherapy: the 7-year LRFS was 97% after adequate surgical margins and 71% after inadequate surgical margins (p < 0.0001), and was 95% in good responders and 90% in poor responders (p = 0.001). Only 1 of 31 patients with local recurrence was free of disease 15 months after the last treatment, 3 were alive with uncontrolled disease and 27 died. This post-relapse outcome is significantly worse than in patients who relapsed with metastases only (25% free of disease, 0.5-9 years after the last treatment). We conclude that, in osteosarcoma of the extremity, limb-salvage procedures should be planned only when the preoperative staging indicates that it is possible to achieve adequate surgical margins. If the pathologic examination of the surgical specimen shows inadequate surgical margins, an immediate amputation should be considered, especially if the histologic response to preoperative chemotherapy was poor.

Adolescent↗

PubMed1997

Continuous administration of the glutamate uptake inhibitor L-trans-pyrrolidine-2,4-dicarboxylate produces striatal lesion.

This study examined the effects of chronic intrastriatal infusion of L-trans-pyrrolidine-2,4-dicarboxylate (PDC), a selective competitive inhibitor of high affinity glutamate transport systems, via osmotic minipumps in rats. Injection of PDC at the rate of 25 nmol/h for 14 days caused striatal lesion. Histological evaluation on frontal striatal sections showed that the lesion was circumscribed to a circular area showing a dramatic neuronal loss accompanied by gliosis and representing 30% of the whole striatal surface at the level of the injection site. A total loss of neurons expressing glutamate decarboxylase (GAD67), enkephalin or substance P mRNA was observed on a similar circular area, suggesting degeneration of the two populations of striatal efferent neurons. In the whole striatum outside the region devoided of hybridization signal, a selective 27% decrease in enkephalin mRNA expression occurred, suggesting a higher sensitivity of enkephalin neurons versus substance P neurons to glutamate uptake-mediated alterations. Injection of PDC at the rate of 25 nmol/h for 3 days produced striatal lesion of similar extent. In contrast, PDC at the rate of 5 nmol/h did not produce neuronal damage when administered over 14 days. This study provides new in vivo evidence that defective glutamate transport is one of the critical conditions that may give rise to toxicity of an endogenous transmitter system in the striatum, and may underlie neuronal death in neurodegenerative diseases.

Animals↗

PubMed1997

Osteogenic sarcoma of the extremity with detectable lung metastases at presentation. Results of treatment of 23 patients with chemotherapy followed by simultaneous resection of primary and metastatic lesions.

BACKGROUND: In the past 20 years, it has been demonstrated that the combination of surgery and chemotherapy improves the prognosis for patients with osteosarcoma of the extremity without detectable metastases at presentation. By contrast, the efficacy of chemotherapy coupled with aggressive surgery has not yet been well established for patients with metastatic disease at diagnosis. The current study evaluates the efficacy of chemotherapy associated with simultaneous surgery of primary and metastatic lesions in patients presenting with osteosarcoma of the extremity with lung metastases. METHODS: Patients with lung metastases originating from an osteosarcoma of the extremity received chemotherapy (high dose methotrexate, cisplatin, doxorubicin, and ifosfamide) followed by simultaneous resection of primary and metastatic lesions and additional chemotherapy. RESULTS: Between January 1993 and June 1995, 23 patients entered the study. After primary chemotherapy, lung metastases disappeared in three patients, whereas in four patients they remained surgically unresectable. All seven patients received surgical treatment of the primary tumor only. In the remaining 16 patients, a simultaneous resection of the primary and metastatic tumors was performed after chemotherapy. The resection of metastatic lesions resulted in a complete remission in 15 patients and an incomplete remission in 1 patient. All five patients who never achieved tumor free status died within a few months. Of the 18 patients who achieved radiologic remission at a 30-month follow-up (range, 14-50 months), 10 (55.5%) remained continuously free of disease, 7 relapsed with new metastases, and 1 died of toxicity. In 13 of the 18 patients who underwent a complete simultaneous resection of the primary and the metastatic lesions, or whose pulmonary metastases disappeared after chemotherapy, a strong correlation was found between degree of necrosis of the primary tumor and of the metastatic tumor. CONCLUSIONS: In patients presenting with osteosarcoma of the extremity with lung metastases, the combination of aggressive chemotherapy with simultaneous resection of the primary and metastatic lesions improves traditionally negative outcomes. The strong correlation found between the histologic response of the primary and metastatic tumors supports the strategy, largely used currently in the neoadjuvant treatment of osteosarcoma, of tailoring postoperative chemotherapy on the basis of the histologic response of the primary tumor to preoperative chemotherapy.

Adolescent↗

PubMed1997

Neoadjuvant chemotherapy for osseous malignant fibrous histiocytoma of the extremity: results in 18 cases and comparison with 112 contemporary osteosarcoma patients treated with the same chemotherapy regimen.

Eighteen patients with high grade malignant fibrous histiocytoma (MFH) of bone and 112 patients with high grade osteosarcoma (OS) of the extremity were treated with neoadjuvant chemotherapy comprised of methotrexate, cisplatinum, doxorubicin and ifosfamide. For the 18 patients with MFH, surgery involved amputation in 2 cases and limb salvage in 16 (89%); the 112 osteosarcoma patients had amputation in 8 cases and limb salvage procedure in 104 cases (93%). The rate of good histologic response to preoperative chemotherapy (90% or more tumor necrosis) was significantly higher in patients with osteosarcoma than in patients with MFH (74% vs 28%; p < 0.003). However, at a median follow-up of 38 months (range 25-61), the 3-year event-free survival (EFS) did not differ in the two groups (MFH 77.8%, OS 70.5%; p = ns). In patients with MFH, no local recurrences were registered, whereas in the osteosarcoma group there were 6 local relapses (5.%). The effectiveness of neoadjuvant chemotherapy in the treatment of osteosarcoma has been assessed during the last 15 years. The results of the present study seem to indicate that, in spite of a usually poor histologic response to preoperative treatment, neoadjuvant chemotherapy is very effective also in MFH of bone.

Adolescent↗

PubMed1997

[The type of local treatment conditions the prognosis in patients with nonmetastatic Ewing's sarcoma of the extremities treated with adjuvant chemotherapy].

The results obtained in 172 cases of non metastatic Ewing's sarcoma of the extremities are reported. The patients were advised to undergo surgical treatment, followed by radiotherapy (40-45 Gy) in case of inadequate surgical margins. 48 patients who refused surgical treatment, were locally treated with radiotherapy alone (50-65 Gy). With a mean follow-up of 8 years (R. 3-15) 101 patients (58.7%) are free of disease and 68 relapsed with metastases and/or local recurrence. A radio-induced bone sarcoma developed in two patients, one patient died of ADM cardiomyopathy. No differences in terms of risk factors were observed between patients who were or were not treated with surgery. A better DFS was observed in the patients treated with surgery (66.9%) in comparison with those treated with radiotherapy alone. The higher percentage of local recurrences observed in patients treated with radiotherapy alone seems to be responsible for the worse prognosis observed in these patients. The authors' conclusion is that the local control in patients with non metastatic Ewing's sarcoma should always be achieved by means of surgery.

Adolescent↗

PubMed1996

Involvement of the glutamatergic metabotropic receptors in the regulation of glutamate uptake and extracellular excitatory amino acid levels in the striatum of chloral hydrate-anesthetized rats.

The microdialysis technique was used to assess in vivo the putative functional role of metabotropic excitatory amino acid receptors in regulating extracellular levels of the excitatory amino acids glutamate and aspartate in the striatum of chloral hydrate-anesthetized rats. Addition of the metabotropic glutamate receptor antagonist (+)-alpha-methyl-4-carboxyphenylglycine (MCPG) (10(-3) or 4 x 10(-3) M) in the dialysis probe did not modify the basal extracellular levels of glutamate and aspartate but induced a significant dose-dependent decrease in the KCl-elicited elevation of glutamate and aspartate extracellular levels. The effect of MCPG on glutamate extracellular concentration under K+ stimulation was reduced by the simultaneous superfusion of the metabotropic glutamate receptor agonist (2S,3S,4S)-alpha-(carboxycyclopropyl)glycine) (L-CCG) (10(-3) M) which had no significant effect when tested alone. In contrast, L-CCG alone significantly potentiated the KCl-elicited elevation of aspartate extracellular concentrations but failed to modify the MCPG effect on this amino acid concentration. In a parallel series of experiments, high-affinity glutamate uptake was measured ex vivo 20 min after an in vivo injection of 10 pmol of MCPG in the striatum. MCPG was found unable to modify the glutamate uptake rate. In vitro, MCPG (1-1000 microM) again had no effect on glutamate transport rate. These data suggest that metabotropic excitatory amino acid receptors (1) may act to increase the extracellular levels of glutamate and aspartate under depolarizing conditions, and (2) may not have a major role in the regulation of high affinity glutamate uptake under basal conditions. In addition, it can be assumed that the control of glutamate and aspartate extracellular levels may involve different metabotropic receptors.

Amino Acids, Dicarboxylic↗

PubMed1996

Synchronous multifocal osteosarcoma: results in twelve patients treated with neoadjuvant chemotherapy and simultaneous resection of all involved bones.

BACKGROUND: Multifocal osteosarcoma is a rare type of tumor which is always excluded from therapy trials and is therefore rarely investigated for prognosis and treatment. PATIENTS AND METHODS: Twelve patients with synchronous multifocal osteosarcoma underwent neoadjuvant chemotherapy and, when feasible, simultaneous resection of involved bones. RESULTS: Four patients were unsuitable for resection and died 5-13 months (average 9 months) later. In eight patients all lesions were resected simultaneously. Four patients are disease-free at 15, 20, 24, and 60 months (average 29 months), and four relapsed and died at 12, 24, 30 and 36 months (average 30.5 months). CONCLUSIONS: Chemotherapy associated with aggressive surgery may be useful. The histological response of different lesions in the same patient are strongly correlated, confirming that synchronous multifocal osteosarcoma is not originally multicentric but unicentric with bone metastases.

Adolescent↗