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R Pelka

Publications and source records attributed to R Pelka.

6 recordsLinked to original sources

Evolution of interfaces and expansion in width

Interfaces in a model with a single, real nonconserved order parameter and purely dissipative evolution equation are considered. We show that a systematic perturbative approach, called the expansion in width and developed for curved domain walls, can be generalized to the interfaces. A procedure for calculating curvature corrections is described. We also derive formulas for local velocity and local surface tension of the interface. As an example, evolution of spherical interfaces is discussed, including an estimate of the critical size of small droplets.

Journal Article↗

Treatment of patients with severe head injury by triamcinolone: a prospective, controlled multicenter clinical trial of 396 cases.

The present studies were conducted to test whether the outcome of severe head injury is improved by early administration of the synthetic corticosteroid triamcinolone. In a prospective, double-blind, multicenter clinical trial, 396 patients with severe head injury were randomized to a steroid group (n = 187) receiving 200 mg triamcinolone acetonide (Volon A soluble) i.v. within 4 h after trauma, followed by 3 x 40 mg/day i.v. for 4 days, and 3 x 20 mg/day i.v. for a further 4 days, and a placebo group (n = 209) receiving injections which did not contain any active drug. The placebo group was subjected to the same standard treatment procedures. Clinical features were not different between the groups upon admission to hospital. Subdural hematoma, epidural hematoma, and focal supratentorial contusion were among the most frequent diagnoses. The result of treatment with triamcinolone was assessed at discharge from the hospital and at 1 year after trauma, using the Glasgow Outcome Scale. Differences in favor of steroid treatment could be detected with regard to the patients' condition at discharge (P = 0.0634). More patients with steroids had a good recovery (49.2% vs 40.7%), and fewer died (16.0% vs 21.5%). Differences in outcome were even more pronounced (P < 0.0145) in patients with a focal lesion and a Glasgow Coma Score on admission of < 8 (n = 93). In this group, 34.8% of the patients made a good recovery, as against 21.3% of the placebo group; mortality was also lower in the verum group (19.6% vs 38.3%). The results indicate that a major subgroup of patients with severe head injury benefits from early administration of triamcinolone. Efficacy of the treatment can be expected, in particular, in patients with a focal cerebral lesion and a Glasgow Coma Score of < 8 on admission. Administration of steroids beginning at the scene of an accident would therefore be beneficial in these cases.

Adolescent↗

[Pharmakokinetics of hydroxy-urea. Therapy of acute myeoblastic leukemias using synchronization and recruitment effects (author' transl)].

By a plasma-concentration of hydroxy-urea (HU) higher than 0.5-2.2x10(-4)M the DNA-synthesis in leukemia cells was blocked reversibly in 9 patients. The plasma half-time of HU varied between 120 and 198 min. To synchronize leukemic cell populations the DNS-synthesis was blocked over a period of 36 hours by maintaining the HU-concentration above the critical lower level. In a second phase-specific therapeutic step cytosine-arabinoside (AraC) was given 4 times in a dose of 1 mg/kg each. A recruitment after the application of AarC made more cells available for the next following synchronization step. 4 acute myeloblastic leukemias with high peripheral cell counts were treated according to this schedule. One patient is still in complete remission for now 14 month. This synchronization/recruitment schedule seems to be successful in acute myeloblastic leukemias with high proliferation rates measured by biochemical and cytokinetic methods.

Administration, Oral↗