Two hundred eighteen healthy children aged 2 to 18 years were studied using a modification of the forced oscillation technique. Reference values with height as predictor were determined for total respiratory resistance and impedance during inspiration, expiration, and throughout the whole respiratory cycle at an oscillation frequency of 4 Hz and, in a subpopulation of 61 children, at frequencies of 2 and 12 Hz. Mean total inspiratory resistance, determined at 4 Hz, decreased with growth from 1.3 kPa X 1(-1) X s at 2 years of age to 0.3 kPa X 1(-1) X s at 18 years. Variability in the results between individuals, expressed in terms of coefficient of variation, was found to be +27% and -21%, respectively, and within individuals, 9%. Resistance during expiration was on average 16% higher than during inspiration and the variability within individuals was 11%. A marked decrease in resistance was found in small children when the frequency was increased from 2 to 12 Hz. The frequency dependence of respiratory resistance observed in small children changes gradually with growth, in parallel with the reduction of total respiratory resistance, to an adult pattern in which no significant change in resistance can be noted between frequencies of 2 and 12 Hz.

Adolescent↗

PubMedDate not supplied

Studies of cerebral blood flow in children with acute lymphoblastic leukemia: case reports of six children treated with methotrexate examined by single photon emission computed tomography.

PURPOSE: Cranial irradiation has been widely used in order to prevent central nervous system (CNS) relapse of acute lymphoblastic leukemia (ALL) in childhood. Owing to the risk of late side effects, the Nordic Society for Pediatric Hematology and Oncology (NOPHO) replaced CNS irradiation with systemic high-dose methotrexate (HDMTX) in 1992. A prospective study of the effects of HDMTX and intrathecal MTX on CNS function is in progress at our center. PATIENTS AND METHODS: Six ALL patients underwent (99m)Tc-HMPAO single-photon emission computed tomography (SPECT) examination of regional cerebral blood flow (rCBF): three owing to neurological symptoms during treatment for ALL and the other three as part of the study. RESULTS: All the patients had various degrees of disturbed rCBF, which was more pronounced in the patients with neurological symptoms. One patient had severe symptoms and impaired rCBF after three intrathecal injections of MTX but before administration of HDMTX. CONCLUSIONS: Impaired cerebral perfusion was found in patients with and without neurological symptoms during treatment for ALL. The impact of these findings is still unknown, from both the long- and the short-term perspective. The possibility that intrathecal MTX alone or in combination with HDMTX may affect rCBF through vascular damage should be further investigated, in terms of both mechanisms and clinical significance.

Adolescent↗

PubMedDate not supplied

Regional cerebral blood flow and neuron-specific enolase in cerebrospinal fluid in children with acute lymphoblastic leukemia during induction treatment.

PURPOSE: To investigate possible side effects on the central nervous system from intrathecal methotrexate given during induction treatment for acute lymphoblastic leukemia in childhood. PATIENTS AND METHODS: Twenty-five children with acute lymphoblastic leukemia were examined by cerebral single photon emission computed tomography at the beginning of treatment (16 untreated, 9 during the first week) and after 4 weeks of treatment. Cerebrospinal fluid was sampled for analyses of neuron-specific enolase on four occasions in 54 patients. RESULTS: Regional cerebral blood flow became impaired during treatment in all patients. The single photon emission computed tomography score for nonhomogeneous perfusion increased from 6.4/50 to 16.6/50. Hypoperfusion was global without any clear preference for any lobe. The cerebellum was not affected. Neuron-specific enolase increased significantly during treatment, with a peak after 1 week, followed by a gradual decrease, but it was still significantly elevated after 4 weeks. CONCLUSIONS: Nonhomogeneous cerebral hypoperfusion was found in all patients during induction treatment, including repeated intrathecal administration of methotrexate, but before systemic high-dose methotrexate. Signs of neuronal injury, in the form of a moderate increase in neuron-specific enolase in the cerebrospinal fluid, were found early in the treatment. Follow-up is needed to evaluate the long-term impact of these findings.

Adolescent↗

PubMedDate not supplied

Pathophysiology of pulmonary embolism with special reference to recurrent embolism.

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Acute Disease↗