We found a variable defect of complex I of the mitochondrial respiratory chain, ranging in severity from 25% to 63% of control values, in muscle of patients with Huntington's disease (HD). The most severe defect was observed in the patient with the greatest expansion of CAG triplets. Muscle morphology showed myopathic changes such as moth-eaten fibers, angulated fibers, increased subsarcolemmal oxidative activities, or an increased number of enlarged mitochondria with abnormal cristae. Multiple mitochondrial DNA deletions were found by polymerase chain reaction (PCR) analysis in muscle of the patient with the most severe defect of complex I. Our data further support the involvement of energetic defects and oxidative damage in muscle of patients with HD.

Aims-To study the loss of heterozygosity at the short arm of chromosome 3 in primary tumours from patients with squamous cell carcinoma of the head and neck; to determine whether the FHIT gene, mapped to 3p14.2 and the CTNNB1 ( -cat) gene, mapped to 3p21, are deleted or mutated in these tumours. Methods-DNA was extracted from fresh tumours. Loss of heterozygosity was assessed by microsatellite analysis of the following markers: D3S1283 and D3S1286 (3p24), D3S966 (3p21), and D3S1300 (3P14.2). Homozygous deletion was determined by radioactive multiplex polymerase chain reaction of exons 5 and 6 of the FHIT gene. The presence of mutations in FHIT exon 5 and -cat exon 3 was studied by single strand conformation polymorphism. Results-50% of informative cases (25/50) showed loss of heterozygosity for at least one of the 3p markers. 3p21 was the region with the highest rate of allelic deletion (63%). No point mutation was found in FHIT exon 5 or -cat exon 3. No case showed homozygous deletion for the FHIT (exons 5 and 6) or the -cat exon 3. Conclusions-The short arm of chromosome 3 is often deleted in the head and neck squamous cell carcinomas. In the remaining alleles of the FHIT or -cat genes, no evidence was found for point mutations or deletions, documented in other common carcinomas. Inactivation could occur by diVerent mechanisms such as methylation, or other genes (not studied here) could be target of allelic losses in squamous cell carcinoma of the head and neck. (J Clin Pathol 1998;51:520-524)

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According to the literature and our own experience, we believe that the initial surgical management of primary and recurrent inverted papillomas limited to the nasal cavity and paranasal sinuses should be endoscopic sinus surgery.

A chronically hyponatremic patient developed neurological features of pontine level disconnection following the raising of serum sodium. At autopsy histopathological examination confirmed the presence of myelinolysis in the central pons and similar symmetrical lesions in the thalamus. In chronic hyponatremic patients, more than the rapidity of correction, the magnitude of the osmolar change may predispose to development of these lesions.