Diagnostic difficulties of isolated symptomatic unilamellar periosteal appositions. Uncommon form of fatigue fracture in children

We describe five cases of painful periosteal reaction occurring in children. The initial radiographic appearance of stress fracture may be troublesome since the new bone formation may be confused with malignant bone lesion. Because of the importance of making a correct diagnosis multiple imaging techniques will often be employed. We discuss the radiographic signs and their usefulness in the differential diagnostic of periosteal reaction.     

Value of systematic post mortem radiographic examinations of fetuses - 400 cases

A retrospective study of 400 cases of fetal deaths has been carried out to assess the value of systematic post mortem radiological examination. Apart from general diagnosis purpose, special attention was given to the assessment of bone age and mineralization. The results were correlated with the clinical, U.S., chromosomal and pathological data. Computerized analysis of our information show the following results: (1) The radiological examination was valuable for the final diagnosis in 13.5% of cases. (2) It brings additional information in 34.5% of cases. (3) It had no diagnostic value in 52%. Furthermore, several points deserve attention such as apparition of teeth (21 weeks), calcaneum (24 weeks). Major osteoporosis was always associated with a constitutional bone disease or an infectious process. An excessive length of the upper limbs (12) was seen in 11 cases of anencephaly. We suggest that a radiological examination should not be routinely performed, when the diagnosis is otherwise obvious, but should be considered in the presence of dwarfism, or other limb abnormalities and when the gestational age is uncertain. The films provide essential information especially for further genetic counselling. Systematic post mortem radiographic examinations are performed in all naturally aborted fetuses over 11 weeks of gestation in our institution. A retrospective study of the last 400 cases was designed in order to assess the value of this examination, with regard to overall diagnosis and assessment of bone maturation and mineralisation. Presented ot the ESPR Meeting in Montreux 1988. Selected for publication by an International Group of the ESPR     

Mechanisms of atrial fibrillation termination by pure sodium channel blockade in an ionically-realistic mathematical model

The mechanisms by which Na+-channel blocking antiarrhythmic drugs terminate atrial fibrillation (AF) remain unclear. Classical "leading-circle" theory suggests that Na+-channel blockade should, if anything, promote re-entry. We used an ionically-based mathematical model of vagotonic AF to evaluate the effects of applying pure Na+-current (I(Na)) inhibition during sustained arrhythmia. Under control conditions, AF was maintained by 1 or 2 dominant spiral waves, with fibrillatory propagation at critical levels of action potential duration (APD) dispersion. I(Na) inhibition terminated AF increasingly with increasing block, terminating all AF at 65% block. During 1:1 conduction, I(Na) inhibition reduced APD (by 13% at 4 Hz and 60% block), conduction velocity (by 37%), and re-entry wavelength (by 24%). During AF, I(Na) inhibition increased the size of primary rotors and reduced re-entry rate (eg, dominant frequency decreased by 33% at 60% I(Na) inhibition) while decreasing generation of secondary wavelets by wavebreak. Three mechanisms contributed to I(Na) block-induced AF termination in the model: (1) enlargement of the center of rotation beyond the capacity of the computational substrate; (2) decreased anchoring to functional obstacles, increasing meander and extinction at boundaries; and (3) reduction in the number of secondary wavelets that could provide new primary rotors. Optical mapping in isolated sheep hearts confirmed that tetrodotoxin dose-dependently terminates AF while producing effects qualitatively like those of I(Na) inhibition in the mathematical model. We conclude that pure INa inhibition terminates AF, producing activation changes consistent with previous clinical and experimental observations. These results provide insights into previously enigmatic mechanisms of class I antiarrhythmic drug-induced AF termination. The full text of this article is available online at http://circres.ahajournals.org     

Topotecan as a radiosensitizer in the treatment of children with malignant diffuse brainstem gliomas: results of a French Society of Paediatric Oncology Phase II Study

BACKGROUND: The current Phase II study was conducted to evaluate the survival and toxicity observed in children with newly diagnosed brainstem gliomas who were treated with the daily radiotherapy with topotecan used as a radiosensitizer. METHODS: Eligible patients were those ages 3-18 years with previously untreated tumors arising in the pons diagnosed within the previous 6 months. Histologic confirmation was not mandatory provided that the clinical and magnetic resonance imaging findings were typical for a diffusely infiltrating brainstem lesion. Treatment was comprised of a 6-week course of topotecan administered intravenously at a dose of 0.4 mg/m(2)/day over 30 minutes within 1 hour before irradiation. Radiotherapy was comprised of a once-daily treatment of 1.8 grays (Gy) per fraction to a total dose of 54 Gy. RESULTS: Thirty-two patients were included in the current study between August 2000 and October 2002. All patients completed the combined treatment in accordance with the treatment design. Only partial responses were observed, occurring in 40% of the patients. The 9-month and 12-month survival rates were 34.4% +/- 8% and 25.5% +/- 8%, respectively. The median duration of survival for these 32 patients was 8.3 months. An intratumoral cystic/necrotic change was observed in five patients, with clinical impairment noted in two patients. One intratumoral hemorrhage occurred during radiotherapy, and was associated with transitory neurologic impairment. CONCLUSIONS: The findings of the current study regarding newly diagnosed brainstem glioma patients treated with topotecan given as a radiosensitizing agent did not reproduce the encouraging results obtained in preclinical studies. Therefore, the concomitant combination of topotecan and radiotherapy at this schedule and these doses cannot be recommended for the treatment of patients with brainstem gliomas.     

Substantially reduced pre-patent parasite multiplication rates are associated with naturally acquired immunity to Plasmodium falciparum

Naturally acquired immunity to Plasmodium falciparum's asexual blood stage reduces parasite multiplication at microscopically detectable densities. The effect of natural immunity on initial prepatent parasite multiplication during the period following a new infection has been uncertain, contributing to doubt regarding the utility of experimental challenge models for blood-stage vaccine trials. Here we present data revealing that parasite multiplication rates during the initial prepatent period in semi-immune Gambian adults are substantially lower than in malaria-naive participants. This supports the view that a blood-stage vaccine capable of emulating the disease-reducing effect of natural immunity could achieve a detectable effect during the prepatent period.     

Hypofractionated radiotherapy in the treatment of diffuse intrinsic pontine glioma in children: a single institution’s experience

We report herein our institutional experience in the treatment of diffuse intrinsic pontine glioma (DIPG) with a hypofractionated external-beam radiotherapy schedule. Between April 1996 and January 2004, 22 patients (age 2.9–12.5 years) with newly diagnosed DIPG were treated by hypofractionated radiation therapy delivering a total dose of 45 Gy in daily fractions of 3 Gy, given over 3 weeks. No other treatment was applied concomitantly. Fourteen of the 22 patients received the prescribed dose of 45 Gy in 15 fractions of 3 Gy, and 2 patients received a total dose of 60 and 45 Gy with a combination of two different beams (photons and neutrons). In five cases the daily fraction was modified to 2 Gy due to intolerance, and one patient died due to serious intracranial hypertension after two fractions of 3 Gy and one of 2 Gy. Among 22 children, 14 patients showed clinical improvement, usually starting in the second week of treatment. No grade 3 or 4 acute toxicity from radiotherapy was observed. No treatment interruption was needed. In six patients, steroids could be discontinued within 1 month after the end of radiotherapy. Median time to progression and median overall survival were 5.7 months and 7.6 months, respectively. External radiotherapy with a radical hypofractionated regimen is feasible and well tolerated in children with newly diagnosed DIPG. However, this regimen does not seem to change overall survival in this setting. It could represent a short-duration alternative to more protracted regimens.