Four cases of spinal accessory nerve passing through the fenestrated internal jugular vein.

PURPOSE: Neck dissection (ND) is an important technique for the treatment of cervical lymph node metastasis in patients with head and neck cancer. Since the introduction of functional ND (FND), various modifications have been made to reduce the adverse effects of radical ND. Recently, many investigators have documented cases of FND with preservation of the spinal accessory nerve (SAN) and/or the sternocleidomastoid muscle, which have contributed to improve the quality of life following ND. For this type of ND, special attention must be paid to identify the SAN and the internal jugular vein (IJV). METHODS: We performed 123 NDs over 2 years at the Department of Otolaryngology, Head and Neck Surgery, Kobe University Hospital. We collected data of all patients who underwent NDs by retrospectively reviewing the relevant hospital medical records and operative notes. RESULTS: In 4 out of 123 NDs (3.3%), an anomaly of the SAN passing through the fenestrated IJV was observed. CONCLUSION: Although this anomaly is rare, head and neck surgeons should be aware of this anomalous relationship between the SAN and the IJV in order to avoid accidental injury to these structures during ND.

Photoreactivation in Paramecium tetraurelia under conditions of various degrees of ozone layer depletion.

Photoreactivation (PR) is an efficient survival mechanism that helps protect cells against the harmful effects of solar-ultraviolet (UV) radiation. The PR mechanism involves photolyase, just one enzyme, and can repair DNA damage, such as cyclobutane-pyrimidine dimers (CPD) induced by near-UV/blue light, a component of sunlight. Although the balance of near-UV/blue light and far-UV light reaching the Earth's surface could be altered by the atmospheric ozone layer's depletion, experiments simulating this environmental change and its possible effects on life have not yet been performed. To quantify the strength of UVB in sunlight reaching the Earth's surface, we measured the number of CPD generated in plasmid DNA after UVB irradiation or exposure to sunlight. To simulate the increase of solar-UV radiation resulting from the ozone layer depletion, Paramecium tetraurelia was exposed to UVB and/or sunlight in clear summer weather. PR recovery after exposure to sunlight was complete at a low dose rate of 0.2 J/m2 x s, but was less efficient when the dose rate was increased by a factor of 2.5 to 0.5 J/m2 x s. It is suggested that solar-UV radiation would not influence the cell growth of P. tetraurelia for the reason of high PR activity even when the ozone concentration was decreased 30% from the present levels.

Osteochondritis dissecans after rotational acetabular osteotomy for dysplastic hip.

We encountered a rare case of osteochondritis dissecans of the femoral head after rotational acetabular osteotomy that recovered with conservative treatment 4 years after the detection of characteristic radiological findings.