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Biomedical subjects

B L Koch

Publications and source records attributed to B L Koch.

10 recordsLinked to original sources
PubMed1998

Central nervous system relapse of treated stage IV neuroblastoma.

Neuroblastoma is the most common extracranial solid tumor in pediatrics. The long-term survival of patients with advanced-stage neuroblastoma has remarkably improved secondary to aggressive treatment protocols including autologous bone marrow transplant (BMT). As a result, a different natural history of this disease is being reported with unusual, late manifestations. The central nervous system (CNS), once a rare site of disease, is being involved with increasing frequency. Appropriate neuroimaging in these patients is important. Two cases of patients with treated stage IV neuroblastoma who developed isolated CNS metastases are presented. The proposed pathogenesis and neuroradiologic manifestations of this complication are reviewed.

Adrenal Gland Neoplasms↗
PubMed1998

Air bag-related deaths and serious injuries in children: injury patterns and imaging findings.

BACKGROUND AND PURPOSE: As of November 1, 1997, automotive air-bag deployments occurring in low-speed collisions had resulted in the deaths of 49 children and in the serious injuries of 19 children in the United States. The purpose of this study was to investigate the patterns of injury occurring in this new mechanism of pediatric trauma. METHODS: In search of common patterns of injury, three pediatric radiologists retrospectively evaluated the available autopsy and imaging studies in 11 such cases not previously reported in the medical literature, in addition to three published case studies. RESULTS: The cause of death or serious injury in every case was the direct result of neurologic injury. Injury patterns differed according to the child's age and type of restraint used at the time of collision. Crush injury to the skull predominated in infant victims traveling in rear-facing child safety seats, and both cranial and cervical spine trauma occurred in older children traveling restrained, improperly restrained, or unrestrained in the vehicle's front passenger seat. CONCLUSION: Air-bag systems pose a potentially fatal threat to the front-seat child passenger. This is directly related to the biomechanics at impact placing the child closer to the deploying air bag. An understanding of the biomechanics provides the radiologist insight into the two types of injury patterns observed.

Air Bags↗
PubMed1997

Phosphorylation of Cbl following stimulation with interleukin-3 and its association with Grb2, Fyn, and phosphatidylinositol 3-kinase.

We have demonstrated that a 120-kDa protein, identified as Cbl, becomes rapidly phosphorylated on tyrosine residues following stimulation of factor-dependent cells with interleukin-3 (IL-3). Little or no phosphorylation of Cbl was observed in the absence of IL-3 stimulation and phosphorylation is maximal by 20-30 min after IL-3 stimulation. Association of Cbl with Grb2 was noted in unstimulated cells, and the amount of Cbl associated with Grb2 increased following IL-3 stimulation. The p85 subunit of phosphatidylinositol 3-kinase was constitutively associated with Cbl. Approximately 10% of the PI kinase activity present in anti-phosphotyrosine immunoprecipitates was present in anti-Cbl immunoprecipitates of IL-3-stimulated cells. The constitutive association of Cbl with Fyn was also observed. Cbl was observed to bind to bacterial fusion proteins encoding the unique, SH3, and SH2 domains of Fyn, Hck, and Lyn. The SH2 domain of Fyn alone was able to bind Cbl to nearly the same extent as did the fusion protein encoding the unique, SH3, and SH2 domains. This was not the case for the SH2 domain of Hck, however, as binding of the Hck fusion protein to Cbl appeared to require multiple domains. The binding of the fusion proteins to Cbl occurred regardless of whether Cbl was tyrosine-phosphorylated or not, and the binding could not be disrupted by the addition of 30 mM free phosphotyrosine. These data suggest the unexpected conclusion that the Fyn SH2 domain may bind to Cbl in a phosphotyrosine-independent manner.

Adaptor Proteins, Signal Transducing↗
PubMed1997

Phosphorylation of cbl after stimulation of Nb2 cells with prolactin and its association with phosphatidylinositol 3-kinase.

Stimulation of Nb2 cells with PRL results in the rapid phosphorylation of a 120-kDa protein identified as the adapter protein cbl on tyrosine residues. Maximal phosphorylation of cbl occurs at 20 min after PRL stimulation and declines thereafter. Stimulation with as little as 5 nM PRL resulted in the phosphorylation of cbl; increasing the concentration of PRL to 100 nM had only a minimal effect upon the phosphorylation of cbl. The cbl protein appears to be constitutively associated with grb2 and the p85 subunit of phosphatidylinositol 3-kinase (PI 3-kinase). The constitutive association of cbl with the p85 subunit of PI 3-kinase was observed in Nb2 cells as well as in 32Dcl3 cells transfected with either the rat Nb2 (intermediate) form of the PRL receptor or the long form of the human PRL receptor. A glutathione S-transferase fusion protein encoding the SH3 domain of the p85 subunit of PI 3-kinase bound to cbl in lysates of both unstimulated and PRL-stimulated Nb2 cells; however, neither of the SH2 domains of p85 bound to cbl under the same conditions. PRL stimulation increased the cbl-associated PI kinase activity. The majority of PI kinase activity appeared to be cbl-associated after PRL stimulation. These results suggest that cbl may function as an adapter protein in PRL-mediated signaling events and regulate activation of PI 3-kinase. Our model suggests that the p85 subunit of PI 3-kinase is constitutively associated with cbl through binding of the p85 SH3 domain to a proline-rich sequence in cbl. After the tyrosine phosphorylation of cbl, an SH2 domain(s) of p85 binds to a specific phosphorylation site(s) in cbl, leading to the activation of PI 3-kinase.

Adaptor Proteins, Signal Transducing↗
PubMed1997

Safety and efficacy of sedation in children using a structured sedation program.

OBJECTIVE: The purpose of this study was to evaluate the safety and efficacy of sedating pediatric outpatients in a radiology department using a structured sedation program modeled after the guidelines of the American Academy of Pediatrics. MATERIALS AND METHODS: Medical records of 6006 pediatric outpatients who underwent sedation for imaging studies under the guidelines of a structured sedation program were retrospectively reviewed for safety and efficacy of sedation, complications related to sedation, and rate of successful sedation. RESULTS: No cases of cardiovascular or respiratory arrest or fatalities occurred. Four children who required overnight hospitalization because of CNS depression had no sequelae. Forty-eight patients experienced transient respiratory depression that proved responsive to supplemental oxygen. Delayed complications were found in 29 children, none of whom required hospitalization. The rate of sedation failure was approximately 1%. CONCLUSION: Sedation of children can be done in a safe and highly efficacious manner in a hospital radiology department using a structured sedation program modeled after the guidelines of the American Academy of Pediatrics.

Adolescent↗
PubMed1997

Congenital epulis.

Congenital epulis of the newborn is a rare gingival tumor that occurs along the alveolar ridge. We report the prenatal sonographic and postnatal MR imaging findings in an infant with maxillary and mandibular congenital epulides.

Adult↗
PubMed1994

Congenital malformations causing skull base changes.

Recent advances in imaging have enabled both the clinician and radiologist to better understand the therapeutic implications of congenital anomalies involving the skull base. Critical to this understanding is a full knowledge of normal embryologic development, anatomic detail, and clinical manifestations in the wide variety of congenital malformations involving the skull base. This review focuses on individual malformations in terms of their pathophysiology and their imaging findings of critical importance.

Bone Diseases, Developmental↗