Treatment of intracranial ependymomas of children: review of a 15-year experience

PURPOSE: There are still major controversies in the optimal management of children with intracranial ependymomas. To assess the impact of tumor site, histology, and treatment, the outcome of children treated at the Institut Gustave Roussy was reviewed retrospectively. METHODS AND MATERIALS: Between 1975 and 1989, 80 children aged 4 months to 15.8 years were seen at the Institut Gustave Roussy for postoperative management of an intracranial ependymoma. Location of tumor was infratentorial in 63 cases and supratentorial in 17. Surgical treatment consisted of complete resection in 38, incomplete resection in 38 and biopsy only in 4. Postoperative irradiation was done in 65 patients and chemotherapy in 33. Surviving patients have been followed from 12-197 months with a median of 54 months. RESULTS: The 5-year actuarial survival and event-free survival are 56% and 38%, respectively. Thirty-four patients relapsed from 3-72 months after diagnosis (median 25 months). In 20 patients, the only site of failure was the original tumor site. Three patients failed locally and at distance, while 10 others failed only at distance. Survival at 5 years was significantly better for patients who had complete resection of the tumor (75% vs. 41%, p = 0.001) and for those who received radiation therapy (63% vs. 23%, p = 0.003). Event-free survival at 5 years was superior in patients with complete resection of the tumor (51% vs. 26%, p = 0.002) and in patients who received radiation therapy (45% vs. 0%, p < 0.001). Sex and tumor site had no impact on survival or event-free survival. There was no difference in survival, event-free survival, or pattern of failure between patients treated with local field, whole brain or craniospinal irradiation, while severe longterm sequelae were noted predominantly in the latter two groups. CONCLUSION: Considering that failures were predominantly local and that there was no apparent benefit from prophylactic irradiation, we recommend local field irradiation with doses above 50.0 Gy for all children with intracranial ependymomas, without meningeal dissemination at diagnosis. Special considerations are necessary for children < 3 years of age.     

Polymerase chain reaction analysis of allele frequency and loss at the Harvey ras locus in myeloid malignancies

The hypothesis that 'rare' variable number tandem repeat (VNTR) alleles of the Harvey ras (Ha-ras) locus are an inherited predisposing factor in myeloid malignancies has been evaluated. We describe an application of the polymerase chain reaction (PCR) which amplifies the VNTR region at the Ha-ras locus and offers a number of advantages over conventional Southern analysis. Ha-ras VNTR genotypes were assigned to 57 normal subjects, 46 patients with acute myeloid leukaemia (AML), 26 with myelodysplastic syndrome (MDS) and 49 with chronic granulocytic leukaemia (CGL). By comparison with previous reports we found significantly higher frequencies of rare alleles (20.2%) in our normal subjects of whom more than 35% had at least one 'rare' allele. The frequencies of rare alleles in the patient groups was not significantly different from the normal group (chi 2 = 0.54, p = 0.91). In studies of constitutional and leukaemic DNA from patients with AML, we found that allelic loss at the Ha-ras locus was not a common phenomenon. The improved resolution achievable with PCR compared with Southern analysis was demonstrated by the inability of Southern analysis to resolve six out of 34 PCR heterozygotes. We therefore suggest that previous studies showing linkage between rare Ha-ras alleles and susceptibility to malignancy should be reevaluated using our sensitive PCR technique.     

Analysis of solid renal dysplasia by flow cytometry: malignant potential?

The iron-chelating agent desferrioxamine now finds extensive use in the treatment and diagnosis of aluminum-related diseases in renal patients. We review the chemistry and pharmacokinetics of desferrioxamine in chelation therapy for patients on hemodialysis.     

Inhibition of morphine-induced tolerance and dependence by a benzodiazepine receptor agonist midazolam in the rat

We investigated whether midazolam administration influenced morphine-induced antinociception and tolerance and dependence in the rat. Antinociception was assessed by the tail-flick (TF) and the hot-plate test (HP 52 degrees C). Morphine tolerance developed after daily single injections of morphine for 11 days. The effect of midazolam on morphine-induced antinociception and tolerance was assessed by giving daily injections of various doses of midazolam for 11 days. The first injection of saline or midazolam was given intraperitoneally and 30 min later morphine (10 mg/kg body weight) was administered subcutaneously. Antinociception was monitored by measuring TF and HP latencies 60 min after the second injection. Midazolam was injected at four different concentrations: 0.03, 0.1, 0.3, and 3 mg/kg body weight. Chronic administration of morphine resulted in the development of tolerance to antinociception in both TF and HP tests, with rats exhibiting baseline antinociception on Day 9. Animals treated with midazolam alone showed little antinociception on Days 3-9. However, midazolam administration in morphine-treated animals attenuated morphine-induced tolerance to antinociception on Days 1-11 as measured by the tail-flick test. Midazolam also decreased the jumping behavior following naloxone injections in morphine-dependent rats. These results suggest that midazolam may prolong the effects of morphine by delaying morphine-induced development of tolerance to antinociception. Midazolam also attenuated a decrease in weight gain induced by chronic injections of morphine.     

Preliminary investigation of the efficacy of sublingual verapamil in the management of acute atrial fibrillation and flutter

The antiarrhythmic properties of sublingual verapamil were investigated in seven patients with acute fast atrial flutter (n = 2) or fibrillation (n = 5). A rapid and significant (P < 0.05) reduction in the ventricular rate was achieved in all seven patients. The ventricular rate at peak plasma verapamil concentration (+/- s.d.) was significantly slower than on admission (101.6 +/- 11.3 and 159 +/- 5.3 beats min-1 respectively, P < 0.01). The ventricular rate remained controlled for over 4 h. Sublingual verapamil was rapidly absorbed with the maximum peak plasma concentration (153.3 +/- 15.5 ng ml-1) being achieved after 1.21 +/- 0.18 h. Side-effects of sublingual verapamil were limited to one report of a bitter taste. The sublingual administration of verapamil may provide an alternative method for the control of acute fast atrial fibrillation and flutter in selected patients.     

Inhibition of experimental neointimal hyperplasia and thrombosis depends on the type of vascular injury and the site of drug administration

BACKGROUND: Heparin inhibits vascular smooth muscle cell proliferation in tissue culture and limits neointimal hyperplasia after experimental arterial injury but has been ineffective in reducing clinical restenosis. We examined how this discrepancy might reflect suboptimal drug-tissue interactions and/or differences in the vascular response to injury. METHODS AND RESULTS: Intravenous infusion was compared with local administration of heparin to injured rabbit iliac arteries either from drug-impregnated polymeric controlled release matrices in the perivascular space or from drug-releasing endovascular stents. Occlusive thrombosis, seen in 42% of control stent-bearing arteries, and partial thrombosis were virtually eliminated by heparin delivery from any route. Intimal area 14 days after balloon withdrawal denudation alone was reduced to an equal extent by continuous systemic heparin or by perivascular heparin for the first 3 days. In contrast, endovascular stents produced more exuberant neointimal hyperplasia, the inhibition of which required continuous rather than only early heparin administration. Neither perivascular delivery limited to the first 3 days nor stent-based delivery reduced neointimal hyperplasia as effectively. CONCLUSIONS: The antiproliferative and antithrombotic effects of heparin differ markedly, depending on the type of arterial injury and the mode of drug administration. Different forms of injury may require different therapies, and complications of arterial intervention such as excessive neointimal hyperplasia and thrombosis may demand alternate therapeutic regimens. Duration, dose, and site of delivery rather than frank resistance to therapy may explain why experimentally effective antiproliferative and antithrombotic agents fail clinically.     

Controlled-release products for the control of the estrus cycle in cattle, sheep, goats, deer, pigs, and horses

This paper describes the estrus cycles of a number of livestock breeds and reviews the controlled-release drug delivery systems that are currently available for the purpose of controlled breeding. The bovine estrus cycle is reviewed in detail, and the estrus cycles of other species are described in a manner that highlights similarities and differences between species. Pertinent formulation and pharmacokinetic information about current drug delivery systems is presented and discussed, and recent advances in this area are also described.