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Biomedical subjects

R W Seiler

Publications and source records attributed to R W Seiler.

87 records · Page 5Linked to original sources
PubMed1981

Adjuvant chemotherapy with procarbazine, vincristine and prednisone for medulloblastomas. A preliminary report.

The survival of 20 children with medulloblastoma who received adjuvant chemotherapy with procarbazine, vincristine and prednisone after resection and craniospinal irradiation is compared with the preliminary results of the Children's Cancer Study Group (CCSG) and the international Society of Pediatric Oncology (SIOP) medulloblastoma studies. Survival with the chemotherapy used in the SPOG study ws not superior to the survival of children who received craniospinal irradiation only.

Cerebellar Neoplasms↗
PubMed1980

Adjuvant chemotherapy with VM 26 and CCNU after operation and radiotherapy of high-grade supratentorial astrocytomas.

Thirty-one patients with histologically proven malignant (Grade III and IV) astrocytomas were randomly placed in one of two treatment schedules two weeks after gross total or subtotal tumor removal. One group (15 patients) received radiation therapy and adjuvant chemotherapy with VM 26 and CCNU once every four weeks, commencing four weeks after the completion of radiotherapy. The second group (16 patients) received radiotherapy alone. The duration of the progression-free interval from operation to recurrence was measured to evaluate the effect of the adjuvant chemotherapy. The median free interval calculated by the computer analysis according to the method of Kaplan and Meier was 65.5 weeks for the chemotherapy group and 40.0 weeks for the control group. The difference is not statistically significant. From our experience, adjuvant chemotherapy should only be given to patients with residual or progressive tumors following radiation therapy.

Adult↗
PubMed1980

Combination chemotherapy with VM 26 and CCNU in primary malignant brain tumors of children.

13 children with inoperable or recurrent primary malignant brain tumors after previous resection and/or radiotherapy were treated with corticosteroids and a combination of VM 26 and CCNU. There were 10 (78%) patients that responded, 1 with a complete and 9 with a partial response with a median duration of response of 8 months (mean 12.5 months). Toxicity was mainly hematological and of acceptable degree. We recommend combination chemotherapy with VM 26 and CCNU for recurrent primary malignant brain tumors of children.

Adolescent↗
PubMed1979

Preoperative radiotherapy and chemotherapy in hypervascular, high-grade supratentorial astrocytomas.

From a group of ten patients with hypervascular, high-grade, supratentorial astrocytomas, five were treated with pre-operative radiotherapy alone, and five with radiotherapy in combination with cytostatic drugs. The aim was to investigate the timing of intracranial operations in the multimodality therapy of brain tumors. The tumor size was diminished only in one case, but tumor vascularization was reduced in half of the cases by the pre-operative treatment. Survival was not improved. Surgical treatment still should be the first of the therapeutic measures. Pre-operative radiotherapy may be of value to reduce tumor vascularization in hypervascular, centrally localized tumors.

Adult↗
PubMed1979

Delayed response to brain tumor chemotherapy.

Five cases of recurrent malignant gliomas are reported. They showed unequivocal and long-lasting improvement of the clinical status and brain scintigram after progressive clinical and scintigraphic deterioration occurred during the initial courses of chemotherapy. The differential diagnosis of tumor regrowth and this unusual delayed response are discussed. Swelling of dead tumor cells and a secondary inflammatory reaction could explain the initial clinical deterioration. The delayed response may be consistent with the slow removal of dead cells from the brain. This has been observed experimentally. Evaluation of the response of a malignant glioma to chemotherapy should be made by serial observations during a sufficiently long period of time.

Adult↗
PubMed1979

Primary intraventricular oligodendrogliomas.

Two cases of primary intraventricular oligodendrogliomas which were successfully removed by a transventricular approach using microtechniques are presented. Oligodendrogliomas in this location are very rare. The literature is reviewed.

Adolescent↗
PubMed1979

Combination chemotherapy with VM 26 and CCNU in primary malignant brain tumors.

Twenty-seven patients with inoperable or recurrent primary malignant brain tumors after previous resection and/or radiotherapy, were treated with corticosteroids and a combination chemotherapy consisting of VM 26 and CCNU. There were 15 (55%) patients that responded, three with a complete and 12 with a partial response with a mean duration of response of 13.4 months. Toxicity was mainly hematological and of acceptable degree. Combination chemotherapy with VM 26 and CCNU is well tolerated and can be administered on an out-patient basis. In our experience it is better than single agent chemotherapy.

Adolescent↗
PubMed1978

Supratentorial haemangioblastoma. Case report.

A case of supratentorial haemangioblastoma is presented. Diagnostic examinations, including computerized axial tomography, were not accurate. Histological examination of the removed tissue disclosed the correct diagnosis. Supratentorial haemangioblastomas are very rare tumours. We describe a case with regard to preoperative neuroradiological investigations, computerized axial tomography, and final histological diagnosis.

Adult↗
PubMed1978

Radiotherapy combined with procarbazine, bleomycin, and CCNU in the treatment of high-grade supratentorial astrocytomas.

Twenty consecutive patients with supratentorial Grade III and IV astrocytomas were treated with postoperative radiotherapy, and a simultaneous induction chemotherapy with 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU), procarbazine, bleomycin, and maintenance chemotherapy with CCNU. They were compared to 32 retrospective control patients selected similarly, who had received postoperative radiation therapy alone. The median survival time was 56 weeks for the combined treatment group, and 51 weeks for the control group. There was no statistical difference in survival in the two groups of patients.

Adolescent↗
PubMed1978

Adjuvant chemotherapy with intraventricular methotrexate and CCNU after surgery and radiotherapy of medulloblastomas.

Seven patients were treated with a combination of intraventricular methotrexate (MTX) and oral CCNU after resection and whole CNS irradiation of medulloblastomas. 3 patients survived 3 or more years after the operation which is not different from reported series with postoperative radiotherapy only. Adjuvant chemotherapy is experimental and should be employed only in controlled studies. The inadequate bone marrow reserve after previous spinal irradiation is a major problem. Because of its delayed and unpredictable myelotoxicity, CCNU is in our experience not a suitable substance for adjuvant combination chemotherapy of medulloblastomas. No complication was observed with 81 intraventricular injections of MTX. It is a good agent and deserves further clinical trials in less myelotoxic combinations.

Brain Neoplasms↗
PubMedDate not supplied

Evaluation of cerebrovascular disease by combined extracranial and transcranial Doppler sonography. Experience in 1,039 patients.

Results from 1,039 combined cervical and transcranial Doppler examinations are reported. Satisfactory transcranial signals were not found in 2.7% of the cases. Compared with angiography, the accuracy of transcranial criteria in assessing collateral flow over the circle of Willis was 94 and 88% for anterior and posterior circulation, respectively. The method also appeared very promising for detection of lesions of the intracranial arteries although the number of such cases with angiographic verification was limited in the present series. Arterial narrowing due to cerebral vasospasm was diagnosed with a sensitivity of 80%. In patients with ruptured intracranial aneurysms, an incidence of 93% arterial narrowing in basal cerebral arteries was found. Patients with subarachnoid hemorrhage and no aneurysm on angiography also showed arterial narrowing with an incidence of 56%. It was possible to monitor the time course and severity of cerebral vasospasm. Arteriovenous malformations were characterized by Doppler findings of high velocities and low pulsatilities. These lesions were diagnosed with an accuracy of 95%.

Cerebral Angiography↗
PubMedDate not supplied

A mathematical model for the estimation of human embryonic and fetal age.

Precise determination of donor age in human embryonic and fetal tissue is crucial for cell transplantation due to the existence of distinct time windows within which successful grafting is possible. This study demonstrates that between 4-12 wk postconception embryonic and fetal age can be estimated based on various morphometric parameters measured on a routine basis in suction abortion material. The greatest length, the neck-rump length, the foot length, and the proximal and distal arm and leg length were correlated with the anamnestic and ultrasonographically estimated age. Multivariate regression analyses showed a linear correlation between age and the logarithmic value of the various morphometric parameters. The best correlation was found for a mathematical model combining the limb parameters (r = 0.904; p < 0.001; n = 37). A prospective follow-up study (n = 40) was carried out to test the validity of the mathematical model. A high correlation was found between the calculated age and the estimated age based on anamnestic data (r = 0.749, p < 0.001). Outliers due to errors in the anamnestic data were readily identified by comparing anamnestic with calculated age. This method allows determination of embryonic and fetal age within and beyond the age group of the Carnegie classification and may, therefore, be useful for the needs of experimental and clinical cell transplantation.

Animals↗
PubMedDate not supplied

GDNF increases the density of cells containing calbindin but not of cells containing calretinin in cultured rat and human fetal nigral tissue.

Among the dopaminergic neurons in substantia nigra pars compacta and in the ventral tegmental area, subpopulations express the calcium-binding proteins calbindin (CB) and calretinin (CR), and the CB-containing neurons are supposed to be less prone to degeneration in Parkinson's disease. Glial cell line-derived neurotrophic factor (GDNF) is a potent survival factor for nigrostriatal dopaminergic neurons. Using free-floating roller-tube (FFRT) cultures derived from fetal rat (E14) ventral mesencephalon we found that GDNF (10 ng/ml) significantly increased the number of surviving tyrosine hydroxylase (TH)-immunoreactive neurons. The possible effects of GDNF treatment on CB-immunoreactive (CB-ir) and CR-ir neurons in such cultures were examined in the present study. The neuronal cell densities were measured by quantifying the numbers of CB-ir and CR-ir neurons in areas of sections through the most extensive parts of the spherical cultures. In 4-day-old and 8-day-old cultures GDNF treatment increased the density of CB-ir neurons by 50% and 59%, respectively. Partial co-existence of TH and CB was shown using the method of double immunolabeling. The density of CR-containing neurons was unaffected by GDNF treatment as confirmed by Western blotting for CR. Parallel effects of GDNF treatment were obtained for cultures of human fetal ventral mesencephalon (8 weeks postconception). In conclusion, our findings identify GDNF as a potent factor for fetal rat and human nigral CB-ir neurons able to promote their survival in culture. Referring to a suggested neuroprotective role of CB, the results may be of relevance in the context of neuronal transplantation of patients suffering from severe Parkinson's disease.

Animals↗