Induction of the rat hepatic microsomal mixed-function oxidases by two aza-arenes. A comparison with their non-heterocyclic analogues.

The ability of the aza-aromatic polycyclic aromatic hydrocarbons 10-azobenz(a)pyrene and benz(a)acridine to induce the rat hepatic microsomal mixed-function oxidases was compared to that of their non-heterocyclic analogues benz(a)pyrene and benz(a)anthracene respectively. All four hydrocarbons markedly increased the O-deethylations of ethoxyresorufin and ethoxycoumarin, the non-heterocyclic analogues being the more potent. A more modest increase was seen in the O-dealkylation of pentoxyresorufin. All four hydrocarbons induced proteins recognised by antibodies to cytochrome P-450IAI but no increase was seen when antibodies to cytochrome P-450IIB1 were employed. The metabolic activation of benz(a)pyrene and Glu-P-1 to mutagenic intermediates in the Ames test was enhanced by all pretreatments. It is concluded that the aza-aromatic polycyclic hydrocarbons, like their non-heterocyclic analogues, selectively induce the cytochrome P-450I family of proteins.

Octoson imaging in pediatric urology.

Ultrasonic imaging of infants and children using an automated transducer water-path delay scanning system (Octoson) overcomes many of the technical difficulties of contact B mode ultrasound imaging and computed tomography. These disadvantages relate to small patient size, motion artifacts, hypothermia, and lack of patient cooperation. Sedation may be required for either conventional study. The automated water-path system is soothing to small children, maintains the body temperature of infants, and avoids direct transducer contact. Sedation is not necessary. Excellent resolution, shorter scan time than computed tomography, and greater flexibility of patient and transducer positioning allows much more complete imaging information. In addition, the panoramic view obtained using this modality serves to demonstrate the complete lesion and its relationship to surrounding structures.

Hyperreninemic hypertension secondary to radiation nephritis in a child.

Radiation injury to the kidney, first reported almost eighty years ago, may vary from subclinical changes in renal blood flow or enzyme activity to clinically significant hypertension and/or renal failure. A child with radiation-induced hyperreninemic hypertension was cured by nephrectomy. The microscopic, subclinical, and clinical changes of irradiation injury are reviewed. The etiology of radiation-induced hypertension, methods of radioprotection, and early detection of radiation renal damage are discussed.

The newborn chest.

Newer therapeutic techniques in the respiratory management of preterm and full-term neonates have resulted in improved survival, particularly in those infants who have respiratory distress syndrome, severe pneumonia, and surgical lesions of the chest. Although respiratory distress syndrome is being seen less frequently because of improved ventilatory management and the use of surfactant replacement therapy, the increased survival of preterm infants has resulted in an increased incidence of bronchopulmonary dysplasia, still a frequently seen pulmonary abnormality. Children who have severe pulmonary disease related to diaphragmatic hernia, meconium aspiration pneumonia, and infectious pneumonia are treated with extracorporeal membrane oxygenation, resulting in a higher survival rate and better outcome. Other abnormalities of the lung, including pneumonia, are seen in both preterm and full-term infants, have characteristic radiographic appearances, and require prompt antibiotic treatment.

Pediatric musculoskeletal magnetic resonance imaging.

MRI has demonstrated clinical applicability and improved diagnostic capability in the musculoskeletal system to a degree rivaling its success in the neurologic system. For certain regions such as the joints, the superficial nature of these structures is ideal for the application of localized radiofrequency coils, enabling considerably improved signal, spatial resolution, and detectable contrast. The multiplanar capability is often invaluable in assessing such regions as the weight-bearing surfaces of the hips. It has been shown to be the most sensitive single test for diagnosing avascular necrosis, and has yielded very high resolution images of the internal architecture of the joints and soft tissues in an entirely noninvasive manner and without the need for the administration of exogenous contrast agents. Short TE images are quite useful in evaluating fatty background regions of interest, such as the bone marrow and subcutaneous tissue, whereas long TR and TE studies are frequently more suitable for soft tissue pathology. The lack of ionizing radiation and the continued failure of intensive research to disclose any deleterious effects at the levels used for clinical diagnostic imaging make this tool especially appealing for application to the pediatric population. With the continual development of new pulsing sequences, contrast agents, and further advances in imaging/spectroscopic correlation, magnetic resonance imaging of the musculoskeletal system is ensured of a solid role in the clinical diagnostic evaluation of the pediatric population.

High dose methotrexate in the treatment of refractory juvenile rheumatoid arthritis.

OBJECTIVE: To assess the response to and safety of long term, high dose (> or = 1 mg/kg/week or > or = 15 mg/m2/week) methotrexate (MTX) administration, in a cohort of 21 children with longstanding, severe juvenile rheumatoid arthritis (JRA). METHODS: Children received MTX at an average weekly dose of 27 mg for a mean of 15.2 months. Outcome was assessed using a disease activity score based on changes in concomitant therapy, laboratory parameters, physician's global assessment, and radiologic evaluation. RESULTS: Seven patients (33%) improved, including one child who achieved complete remission, while 14/21 children (67%) did not benefit from high dose MTX. Subsequently, 6/14 (43%) of the non-responders discontinued high dose MTX and began cyclosporine. Radiologic progression, regardless of clinical outcome, was documented in 10/15 (67%) of the patients. The drug was well tolerated despite mild gastrointestinal symptoms and transient liver enzyme elevation. CONCLUSION: The results of this open retrospective pilot trial suggest that high dose MTX is well tolerated, but that its role in the treatment of children with refractory JRA may be limited. Radiologic progression, despite improvement in the clinical status or in the laboratory parameters, supports the hypothesis that MTX acts as a potent antiinflammatory agent.

Pathology attributed to Mycobacterium chelonae infection among farmed and laboratory-infected Atlantic salmon Salmo salar.

This study was promoted following concern over increasing mortality on 2 farms rearing Atlantic salmon Salmo salar in the Shetland Isles, Scotland. A Mycobacterium sp. was isolated from moribund, market-sized Atlantic salmon. Biochemical tests, lipid analysis and PCR (polymerase chain reaction) techniques confirmed the bacterium to be Mycobacterium chelonae. Multiple greyish-white miliary granuloma-like nodules were observed in several tissues. Dense hard-packed nodules contained abundant acid-fast bacteria. Atlantic salmon injected with M. chelonae remained sub-clinically infected, demonstrating the chronic nature of this disease. The source of the pathogen was not identified.

Pictorial review of the usual and unusual roentgen manifestations of childhood tuberculosis.

Despite advances in management of infectious diseases, tuberculosis remains a significant cause of morbidity and mortality in urban populations. In the pediatric age group, 65% of patients presenting with tuberculosis are asymptomatic. Recognition of the usual and unusual roentgen manifestations of this infectious disease often provides the only clue to the diagnosis.

Complications resulting from treatment of severe posterior epistaxis.

Recent advances in nasal endoscopy and arterial embolization have improved the treatment of severe posterior epistaxis. This report reviews the therapeutic options, including a case of epistaxis that did not respond to nasal packing but was successfully controlled with superselective arterial embolization. The discussion includes an outline of potential complications of epistaxis treatment, including a case of nasal septal perforation.