Biomedical subjects

Kazuki Nagayama

Publications and source records attributed to Kazuki Nagayama.

4 recordsLinked to original sources

PubMed2005

Radiation-induced apoptosis of oligodendrocytes in the adult rat optic chiasm.

OBJECTIVES: The present study characterized glial cell injury provoked in adult rat chiasm within 24 hours after a single, high-dose irradiation of 20 Gy. METHODS: All chiasmal glial cells in a section were counted, and the percentage of TUNEL-positive glial cells exhibiting apoptotic morphology was defined as the apoptotic rate. RESULTS: Numbers of apoptotic cells increased significantly (p<0.0001) from 3 to 8 hours after exposure, but returned to baseline levels by 24 hours. Little evidence of apoptosis was observed in non-irradiated chiasms. Similar patterns of increase in apoptotic rate were observed in the genu of the corpus callosum, but the extent was significantly lower (p=0.047) in the optic chiasm, with a maximal rate of 1.9%. Immunohistochemically, apoptotic cells were positive for CNP, a marker for oligodendrocytes. DISCUSSION: These data indicate that chiasmal irradiation induces limited, but significant apoptotic depletion of the oligodendroglial population, and may participate in the development of radiation-induced optic neuropathy.

Analysis of Variance↗

PubMed2005

[Our current technique for basic pterional craniotomy].

Pterional cnaniotomy is frequently used in neurosurgical practice, but still poses significant cosmetic and functional drawbacks. Here, we describe our modified technique to overcome such problems as the sterilization of the scalp without brush and razor, preemptive analgesia, preservation of the periostium for reconstruction, retrograde dissection of the temporal muscle, and complete sphenoidotomy using chisel or drills. The tips of our pterional craniotomy offer suitable size and depth of working field around the paraclinoidal regions, maintaining cosmetic satisfaction of the patients.

Anesthesia↗

PubMed2003

Frontal sinus repair with free autologous bone grafts and fibrin glue.

BACKGROUND: The authors describe a technique for repairing the frontal sinus with autologous bone grafts removed during craniotomy and fibrin glue. METHODS: This technique was used in 12 patients who underwent craniotomy for aneurysms (n = 9), brain tumors (n = 2), and acute epidural hematoma (n = 1). RESULTS: The repair was successful in all cases. There were no instances of postoperative infection or leakage of cerebrospinal fluid. No complications from the repair have occurred over a mean follow-up of 51 months. CONCLUSION: This technique is simpler than others used to seal a frontal sinus.

Adult↗

PubMed2002

[Cranioplasty using the patient's autogenous bone preserved by freezing--an examination of post-operative infection rates].

The current technique for cranioplasty using artificial bone requires further improvement with regard to infection, strength and comfort through good fitting. We have carried out cranioplasty using the patient's autogenous bone flap obtained during first surgery. It was immersed in 200 mg of Amikacin Sulphate, and frozen at -16 degrees C until its use in cranioplasty. From 1980 to 1998, cranioplasty has been carried out on 206 patients. They consisted of 118 males and 88 females, and their age ranged in our institute from 1 to 81; average age 51.1. Ruptured aneurysm (48%), head injury (14%), intracranial hemorrhage (23%) and cerebral infarction (12%) were the major causes requiring decompression surgery. We analyse the bone preservation period and the time between cranioplasty and the onset of infection. The infection rates per bone preservation periods, the causes of decompression and age groups are studied. Of the 208 case studies, infection necessitating bone removal or debridement was noted in 8 cases (3.88%). Average bone preservation period in the infected group was 31.1 days as compared with 54.9 days for the non-infected group (p < 0.05). Not patient age but the type of head injury is also a significant factor in post cranioplasty infection.

Adolescent↗