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Biomedical subjects

V Nayanar

Publications and source records attributed to V Nayanar.

13 recordsLinked to original sources
PubMed1997

A dose-intensive, cyclophosphamide-based regimen for the treatment of recurrent/progressive or advanced solid tumors of childhood: a report from the Australia and New Zealand Children's Cancer Study Group.

BACKGROUND: Children with solid tumors that progress or recur after conventional multimodality therapies have a very poor prognosis. In a pilot study, vincristine, etoposide, and dose-escalated cyclophosphamide (VETOPEC) was shown to be a promising salvage regimen. Continued accrual of patients and increased duration of follow-up has resulted in substantial experience with VETOPEC. METHODS: Between May 1991 and March 1994, 56 pediatric patients from 6 centers were enrolled in this study; 44 had recurrent or progressive tumors (Group A) and 12 had newly diagnosed, advanced tumors with a very poor prognosis (Group B). The VETOPEC regimen was comprised of vincristine, 0.05 mg/kg, on Days 1 and 14; etoposide, 2.5 mg/kg, on Days 1, 2, and 3; and fractionated, dose-escalated cyclophosphamide on Days 1, 2, and 3. The initial cyclophosphamide dose was 90 mg/kg (2.7 g/m2)/cycle with an escalation of 15 mg/kg/cycle in each subsequent cycle, to a maximum (over 6 cycles) of 165 mg/kg (5.0 g/m2)/cycle. Tumor response was evaluated every two to three cycles and included central review of imaging. RESULTS: The combined and partial response rates for Groups A and B were 66% (25 of 38 patients) and 91% (10 of 11 patients), respectively. In Group A, best evaluable responses and event free (EF) survivors were observed with: brain tumors (7 of 9 patients; 2 EF at 39 and 45 months [mos], respectively), Wilms' tumor (6 of 7 patients; 3 EF at 37-49 mos), and lymphoma (4 of 4 patients; 2 EF at 52 and 59 mos, respectively); in Group B best evaluable responses and EF were observed with: neuroblastoma (5 of 6 patients; 1 disease free at 57 mos) and rhabdomyosarcoma (4 of 4 patients; no survivors). Hematologic toxicity was limiting despite support with myeloid growth factors in 33 patients. Four deaths in Group A and one in Group B were directly associated with this toxicity. Specifically, no cases of drug-related myocardial toxicity or pneumonitis were observed. CONCLUSIONS: This chemotherapy regimen with its intense scheduling produced a high response rate and appreciable survival in patients with a variety of recurrent, progressive, or advanced solid tumors of childhood.

Adolescent↗
PubMed1997

Quantitative MRI in outpatient childhood epilepsy.

PURPOSE: In adult studies, MRI volumetrics is a proven technique in presurgical assessment of epilepsy. Hippocampal volume loss is maximal in the syndrome of mesial temporal lobe epilepsy. We aimed (a) to validate this methodology in a pediatric outpatient epilepsy population (b) to determine the relationship of hippocampal asymmetry (HA) to epileptic syndromes and risk factors. METHODS: Two neurologists classified the epileptic syndrome in 79 pediatric outpatients, according to the International Classification of Epilepsies and Epileptic Syndromes (ILAE). Hippocampal volumetrics were performed in all patients. HA was defined according to adult control values. RESULTS: Inter-rater variability on measurement of HA was very small (Correlation of test retest of 0.97 on 17 children <3 years old). The rate of HA was 44/79 (57%). In 21 patients, (27%) potentially epileptogenic lesions (other than HA) were identified (cerebral dysgenesis n = 11). HA was present in 9/15 (60%) of temporal lobe epilepsy and in 15/28 (54%) extratemporal onset epilepsy and 5/11 (46%) of generalized symptomatic epilepsy. Analysis confined to <13 years also showed HA was not specific for epileptic syndrome. There was no significant association of febrile convulsions (13%) with HA or temporal lobe epilepsy. CONCLUSIONS: There is a high incidence of HA in childhood epilepsy. HA was not confined to clinically defined temporal lobe epilepsy. The poor correlation of epileptic syndrome to quantitative MRI findings may be due to the inadequacies of epilepsy classification in the younger child, with the clinical semiology providing misleading localizing information. Normative childhood data for hippocampal volumes and symmetry is needed.

Adolescent↗
PubMed1996

Two cases of chronic recurrent multifocal osteomyelitis: radiological and scintigraphic findings.

Chronic recurrent multifocal osteomyelitis (CRMO) is an extremely rare condition, of uncertain aetiology. Since first described, in 1972, under 100 cases have been reported. It is being reported with increasing frequency, and many cases of this disease go unreported. It most commonly affects patients in childhood or adolescence. No infective agent has been identified, and antibiotics do not affect the course of the disease. We present the cases of two female children with this disorder, describe the radiological and scintigraphic findings and review the literature. Case 1 is the first reported case to our knowledge of CRMO presenting with cranial nerve palsies.

Bone and Bones↗
PubMed1996

The site of anti-arthritic action of the kappa-opioid, U-50, 488H, in adjuvant arthritis: importance of local administration.

1. Currently available pharmacological therapies treat arthritis inadequately. We have previously found that the kappa (kappa)-opioid, U-50,488H (trans-(+/-)- 3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl) cyclohexyl]- benzene-acetamide methane sulphonate), possesses anti-arthritic effects. In light of the finding that opioid receptors in the periphery are upregulated during inflammation, kappa-opioids may represent a novel therapy for arthritis. The primary aim and unique feature of the present study is to investigate whether opioids exert their anti-arthritic effects in the periphery. Thus, the dose-effect relationship of a kappa-opioid agonist, U-50,488H was compared after both local and distant administration. Further, we tested whether the anti-arthritic effects of this drug are stereospecific and receptor-mediated by use of opioid antagonists. 2. Using an adjuvant model of arthritis in male Lewis rats, arthritis was judged by oedema, radiography and histological changes in the contralateral ankle of the hind limb. Treatment with (+/-)-U-50,488H for 3 days during disease onset and 3 days during established disease significantly attenuated arthritis, but the effects of (+/-)-U-50,488H on radiology and histology varied according to treatment time. Administration of (+/-)-U-50,488H during disease onset had a more marked effect on radiography, suggesting that treatment with that drug should be started early to prevent progressive joint destruction. Further, it was found that (+/-)-U-50,488H, administered for 3 days during the disease onset, either by direct subcutaneous injection into the inflamed paw or at a more distant site into the back of the neck, dose-dependently attenuated arthritic damage as measured by an index which pooled all three variables. More importantly however, (+/-)-U-50,488H was approximately fourfold more potent as an 'anti-arthritic' agent after local compared to distant subcutaneous injection (ED50; local vs distant: 5.8 +/- 1.6 vs 19.5 +/- 0.8 mg kg-1). 3. Equivalent doses of the (-)-enantiomer (20 mg kg-1day-1) and the racemate (+/-) of U-50,488H (40 mg kg-1day-1), elicited a similar attenuation of arthritic parameters while the (+/-)-enantiomer exacerbated arthritis, suggesting that the anti-arthritic activity lies solely with the (-)-enantiomer. 4. Both the peripherally selective antagonist, naloxone methiodide, and the kappa-selective antagonist, MR2266 ((-)-5,9 alpha-diethyl-2-(3-furylmethyl)-2'-hydroxy-6,7-benzomorphan), were able to reverse fully the peripheral anti-arthritic effects of U-50,488H, indicating that it exerts its effects through peripheral kappa-opioid receptors. 5. Taken together, these results not only confirm our previous findings that demonstrate anti-arthritic effects of U-50,488H but they indicate that the opioid attenuation of experimental arthritis is mediated via peripheral kappa-receptors in the arthritic joint. Peripherally acting kappa-opioid agonists should lead to new therapies for arthritis.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1995

Non-ketotic hyperglycinaemia presenting as pachygyria.

A 2-day-old infant with lethargy and hypoventilation had pachygyria and agenesis of the corpus callosum on CT scan. Increased concentrations of glycine in plasma and CSF, together with an increased CSF/plasma ratio, confirmed a clinical diagnosis of non-ketotic hyperglycinaemia. This is the first report of pachygyria in this disorder, although agenesis of the corpus callosum is well recognized, and non-specific gyral malformations have been described previously. The specific diagnosis of an inborn error of metabolism in infants with structural brain malformations is of critical importance for accurate genetic counseling.

Amino Acid Metabolism, Inborn Errors↗
PubMed1995

Anti-inflammatory effects of kappa-opioids in adjuvant arthritis.

Current therapies for arthritis are unsatisfactory and cause serious side effects and morbidity. It has been postulated that opioid drugs may block inflammatory mediators and attenuate the joint damage in adjuvant arthritis. However, the importance of opioid receptor subtypes involved in inflammation remains to be determined because data are conflicting in this regard. The present investigation was designed to test the effects of both a kappa-agonist, (+/-)U50488H and a kappa-antagonist, MR2266 on the progression of experimental arthritis. To produce adjuvant arthritis, male Lewis rats were inoculated subcutaneously (s.c.) with 0.05 ml of Freund's complete adjuvant (10 mg/ml) into the right hind paw. The kappa-opioid agonist, (+/-)U50488H (20 mg/kg/d s.c.) and the kappa-opioid antagonist, MR2266 (20 mg/kg/d s.c.) were administered for 3 days during the primary inflammatory phase of adjuvant arthritis. There were four treatment groups; group I were non-arthritic controls and received paraffin oil vehicle and opioid injections; group II were arthritic controls and received adjuvant and saline injections; group III received adjuvant and agonist and group IV received adjuvant and antagonist. The progression of adjuvant arthritis from day 0 to 24 was monitored by body weight change, hind limb size (ipsilateral and contralateral) and a total severity score for each clinical observation of gait, coat and limb condition. On day 24 histology and radiography of the contralateral limb was performed. There was less soft-tissue swelling, as judged by time-averaged % change in the volume of the contralateral limb, in both agonist (mean +/- se: 82 +/- 5) and antagonist (77 +/- 4) treated rats compared to untreated arthritic controls (99 +/- 5, p < 0.05). Other clinical measures of severity were not different between untreated and opioid-treated arthritic rats. However, the joint damage as judged by radiography was lower in kappa agonist treated rats (2.6 +/- 0.5, p < 0.05) compared to untreated controls (4.1 +/- 0.5) and antagonist treatment (4.4 +/- 0.5). Microscopic pathological scores were also significantly lower in agonist (2.8 +/- 0.3, p < 0.05) compared to both antagonist treated rats (4.2 +/- 0.1) and vehicle-treated controls (3.6 +/- 0.2). The results of this study show that kappa-opioid receptor agonists but not antagonists attenuate the progression of experimental arthritis. These observations have important implications for the evaluation and use of kappa-opioid agents in the management of arthritis.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1994

Dose-intensive cyclophosphamide with etoposide and vincristine for pediatric solid tumors: a phase I/II pilot study by the Australia and New Zealand Childhood Cancer Study Group.

PURPOSE: This pilot study of the Australia and New Zealand Childhood Cancer Study Group investigated the effectiveness and toxicity of a regimen incorporating vincristine (VCR), etoposide, and divided-dose, escalating cyclophosphamide (CPA) (VETOPEC) in 23 patients aged 1 to 20 years with solid tumors. PATIENTS AND METHODS: Seventeen patients (group A) had recurrent or refractory tumors after prior multiagent therapy, and six patients (group B) with adverse prognostic indicators were treated at initial presentation. Treatment cycles were 21 to 28 days and consisted of vincristine (0.05 mg/kg) on days 1 and 14, with etoposide (2.5 mg/kg/d) plus escalating CPA on days 1, 2, and 3. The CPA dosage was escalated from 30 mg/kg/d in cycle no. 1 by 5 mg/kg/d in each cycle to a maximum of 55 mg/kg/d in cycle no. 6. RESULTS: Of 20 patients assessable for tumor response, 19 (95%) responded after two to six cycles of VETOPEC: seven complete responses (CRs); eight very good partial responses (VGPRs); and four partial responses (PRs). In group A, 13 of 14 (93%) assessable patients responded (five CRs, four VGPRs, four PRs), and in group B, five stage IV and one stage III patient achieved two CRs and four VGPRs. The principal toxicity was myelosuppression. Grade IV neutropenia occurred after 98% of cycles, and the incidence of grade IV thrombocytopenia increased from 37% after cycle no. 1 to 91% after cycle no. 6 (P = .002). A total of 115 cycles delivered were followed by 62 febrile admissions (54%), and showed a significant rise with increasing cycles (P = .001). One patient died of septicemia. CONCLUSION: This combination and scheduling produced a high response rate in patients with recurrent, refractory, or advanced solid tumors of childhood. Further studies of this regimen and of strategies to reduce hematologic toxicity are warranted.

Adolescent↗
PubMed1993

Postoperative chemotherapy without radiation in young children with malignant non-astrocytic brain tumours. A report from the Australia and New Zealand Childhood Cancer Study Group (ANZCCSG).

Young children with malignant brain tumours have particularly poor survival and manifest severe sequelae of radiation therapy. A multi-institutional pilot study of post-operative primary chemotherapy for children under 3 years with primitive neuroectodermal tumours (PNET) or ependymoma was initiated in 1987. The chemotherapy protocol comprised carboplatin, vincristine and the "eight drugs in 1 day" regimen. Radiation was recommended only if tumour progression or recurrence was documented. A total of 14 patients between 5 and 36 months of age were enrolled. Seven had supratentorial tumours (PNET, pinealoblastoma, intracranial retinoblastoma) with multiple predictors of adverse outcome. Four of these responded to initial chemotherapy but subsequently progressed and all had died by 16 months from diagnosis. The seven patients with infratentorial tumours (three medulloblastomas, four ependymomas) had more favourable predictors of outcome: no meningeal dissemination and gross macroscopic resection in six of the seven cases. One patient progressed rapidly and died within 5 months. The other six are alive at 37-57 months from diagnosis. Four are in continuous complete remission at 57, 51, 41 and 37 months, respectively from the time of their tumour resection. One is described as having stable disease with a persistent radiographic lesion at 41 months from diagnosis. One has relapsed on two occasions and is the only surviving patient to have been irradiated. Intelligence scores for the six long-term survivors have thus for remained within the normal range. It is suggested that some infants with standard-risk ependymoma and, possibly, medulloblastoma may be cured without radiation therapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1989

Suprasellar arachnoid cysts: management by cyst wall resection.

Five children with ventricular dilatation (4 boys, 1 girl) had features seen on computer tomographic scan that were consistent with suprasellar arachnoid cysts. All children were investigated with a CT ventriculogram and/or CT cisternogram, and no communication with the cyst was demonstrated. Three children were seen in the 1st year of life and the remaining 2 children were between 1 and 5 years of age. Hydrocephalus and developmental delay were the most common presenting features, followed by visual disturbance, squint, or ataxia. Direct surgical decompression was performed in all 5 patients to avoid long-term placement of a ventriculoperitoneal shunt. A temporary shunt was placed in 2 children because of high intracranial pressure. Direct partial excision of the cyst wall to allow long-term drainage into the basal cisterns or ventricular system was successful in all children. The presence of subdural collections postoperatively required temporary shunting in 2 children. After follow-up for between 10 and 22 months no clinical endocrinological sequelae have been detected, but 2 children have raised serum prolactin levels. Three children are developmentally delayed; one of these has regained some skills since surgery. Direct surgical decompression of suprasellar arachnoid cysts to avoid long-term shunt placement is the preferred method of surgical treatment for this condition.

Arachnoid↗
PubMed1985

Role of radionuclide imaging in the diagnosis of chondrosarcoma.

The diagnosis of chondrosarcoma may be difficult if there is an atypical radiographic appearance or an inconclusive biopsy. Radionuclide bone scans of 13 patients with chondrosarcoma were reviewed to assess if a pattern of scan features could be recognised in association with this tumour. A combination, including increased blood pool activity, moderate intensity of uptake, patchy uptake with cortical predominance of activity, minimal distortion of bony outline, and a well-defined scintigraphic margin, occurred regularly in the series. Recognition of this characteristic pattern of scintigraphic features in cases of suspected chondrosarcoma may assist in the diagnostic assessment.

Adolescent↗