Peroxisomal disorders: clinical commentary and future prospects

Recent progress in the classification, biochemistry, and molecular biology of peroxisomal disorders is reviewed from a clinical perspective. Diseases such as Zellweger syndrome, neonatal adrenoleukodystrophy, infantile Refsum disease, hyperpipecolic acidemia, chondrodysplasia punctata, and Leber amaurosis share a common phenotype and involve deficiency of multiple peroxisomal enzymes. These disorders are associated with diverse metabolic abnormalities which are useful in pre- or postnatal diagnosis and distinguish these disorders from others such as X-linked adrenoleukodystrophy, adult Refsum disease, hyperoxaluria type I, and acatalasemia. Peroxisome structure is difficult to quantify histologically, since recent studies emphasize its developmental variability and tissue heterogeneity. The ability to manipulate this structure by dietary or pharmaceutical means provides a novel approach to therapy. At the molecular level, deficiency of peroxisomal enzymes responsible for fatty acid beta-oxidation or ether lipid synthesis reflects enhanced protein degradation due to abnormal peroxisomes; messenger RNA for the beta-oxidation enzymes is transcribed normally in peroxisomal disorders and can be increased by peroxisome proliferators. At least one integral structural protein of the peroxisome is synthesized normally in Zellweger syndrome. Hypotheses for the basic defect include defective regulation, uptake, or coenzyme stimulation of imported proteins, as well as defective biosynthesis. One clue to this defect may be a similar evolutionary history of peroxisomes and mitochondria which would explain their common alteration in Zellweger syndrome.     

Immediate lamina papyracea reconstruction during endoscopic sinus surgery for surgically managed subperiosteal abscess in children

The sinonasal area of a child's face is the keystone of facial architecture, and any trauma to this area may result in facial dysplasia. Animal studies have proven facial skeletal growth retardation following functional endoscopic sinus surgery. The effect of sinus surgery on facial skeletal growth in humans still needs to be established. Therefore, very conservative surgical resection during functional endoscopic sinus surgery in children is advocated. We present a surgical technique of immediate lamina papyracea reconstruction during endoscopic sinus surgery in children. We have used this technique in endoscopic surgical decompression of subperiosteal abscess secondary to sinusitis in children. We present two cases in which this technique was used in children aged 33 months and 8 years old. The postoperative computed tomography scans showed an intact lamina papyracea.     

Transesophageal echocardiographic detection of thrombus superimposed on metastatic left atrial tumor

We present a 32-year-old male with metastatic thymic carcinoma invading the left atrium in whom two-dimensional transesophageal echocardiography was able to differentiate a thrombus superimposed on the tumor.     

Tracking cognitive changes in new-onset epilepsy: functional imaging challenges

Functional imaging has potential for tracking changes in cognition during the onset and evolution of epilepsy. Although the concept of imaging such changes over time is an exciting new direction, feasibility remains an open question. The current article outlines a case example in which functional magnetic resonance imaging (fMRI) and event-related potentials (ERPs) were used to monitor memory changes before and after selective temporal lobe resection. From this example, three key methodologic challenges for new-onset epilepsy are identified and discussed. The first challenge relates to the interpretation of results in regions near epileptogenic tissue. We argue that this is best addressed by collecting information from multiple modalities to test for convergent evidence. The second challenge relates to optimizing the methods for sensitivity to detecting changes. In this case, enhanced imaging methods and a region-of-interest approach provide necessary focus. The third and final challenge relates to the practical difficulties of conducting research in new-onset epilepsy cases. We suggest that greater integration of imaging research within the clinical setting is needed.