Biomedical subjects
Y Sawamura
Publications and source records attributed to Y Sawamura.
[Mixed germ cell tumors].
Explore the source record for details and available documents.
[Production and clinical application of fibrin sealant with high concentrated fibrin (fibrin patch)].
OBJECT: The sealing properties of fibrin sealant with high concentrated fibrin (fibrin patch) were examined. MATERIAL AND METHODS: A commercial fibrin sealant (Bolheal) produced from pooled human plasma was utilized for this study. The fibrin sealant made of fibrinogen and thrombin solutions mixed in a volume ratio 5:1 was applied as the fibrin sealant with high concentrated fibrin (fibrin patch). The burst pressure of the fibrin clots of either 1:1 or 5:1 mixing ratio, which sealed the small holes, was measured by a water-leak preventing model. The tensile strength of the fibrin patch was measured by the breaking pressure of the fibrin clot. The burst pressure of the fibrin patch, which sealed the dural defect with a diameter of 15 mm, was compared with that of expanded polytetrafluoroethylene (ePTFE). RESULTS: The burst pressure was elevated from 287 +/- 23.1 to 445 +/- 30.5 mmHg by changing the mixing ratio from 1:1 to 5:1. The breaking pressure of the fibrin patch showed 131 +/- 25.4 mmHg and that of the patch mixed at the ratio of 1:1 showed 46.6 +/- 9.9 mmHg. The result of dural repair with the fibrin patch revealed higher sealing effectiveness than that of ePTFE. The burst pressure averaged 70.5 +/- 21.4 mmHg in the fibrin patch samples and 51.4 +/- 13 mmHg in the ePTFE samples. CONCLUSION: The fibrin patch revealed higher performance as a sealant and has the potential to be a candidate for acceptance as the new dural repair material.
CYP2A6 gene deletion reduces susceptibility to lung cancer.
CYP2A6 is an enzyme with a high ability to activate a nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), to its potent and ultimate carcinogen. In the present study, we investigated the relationship between genetic polymorphism of CYP2A6 and lung cancer risk in a case-control study of Japanese subjects. Genotyping of the CYP2A6 gene in both healthy volunteers and lung cancer patients was conducted. The frequency with which the subjects carried homozygotes of the CYP2A6 gene deletion-type mutation (deletion), which causes lack of the enzyme activity, was lower in the lung cancer patients than in the healthy control subjects. The odds ratio (OR) of the group homozygous for the deletion was significantly lower and calculated to be 0.25 (95% CI; 0.08-0.83) when the OR for the population with homozygotes of the CYP2A6 wild-type gene was defined as 1.00. In the allelic-base analysis, there was also a significant decrease in the OR for the deletion allele. These data suggest that deficient CYP2A6 activity due to genetic polymorphism reduces lung cancer risk.
Comparison between observation policy and fractionated stereotactic radiotherapy (SRT) as an initial management for vestibular schwannoma.
PURPOSE: To compare the use of an observation policy with that of stereotactic radiotherapy (SRT) for treatment of vestibular schwannoma. METHODS AND MATERIALS: The study group consisted of 27 patients who underwent observation as an initial treatment (observation group) and 50 who received SRT (SRT group). The mean follow-up period was 35 months and 31 months, respectively. Stereotactic radiotherapy consisted of small-field fractionated radiotherapy (36-44 Gy in 20-22 fractions over 6 weeks) with or without a subsequent 4-Gy single irradiation boost. RESULTS: Actuarial tumor control rate of the SRT group was significantly better than that of the observation group (p < 0.0001). The mean growth was 3.87 mm/year in the observation group and -0.75 mm/year in the SRT group (p < 0.0001). Eleven patients (41 %) in the observation group and 1 (2 %) in the SRT group received salvage therapy (p < 0.001). There was no difference in the actuarial Gardner and Robertson's class preservation curves for 5 years after the initial presentation. CONCLUSION: Stereotactic radiotherapy using a fractionated schedule provides a better tumor control rate and a similar rate of deterioration for hearing levels compared to an observation policy. Initial SRT may be a reasonable alternative to a wait-and-see policy.
Preirradiation evaluation and technical assessment of involved-field radiotherapy using computed tomographic (CT) simulation and neoadjuvant chemotherapy for intracranial germinoma.
PURPOSE: To investigate the importance of preirradiation mental and endocrinological evaluation, and the effectiveness of involved-field radiotherapy following neoadjuvant chemotherapy. METHODS AND MATERIALS: Following etoposide and cisplatin with or without ifosfamide, 13 patients with nondisseminated disease received involved-field irradiation of 24 Gy in 12 fractions within 3 weeks and 2 patients with disseminated germinoma received 24 Gy craniospinal irradiation (CSI). CT simulation was used to cover the tumor bed. RESULTS: Full-scale intelligence quotient (IQ) tests given at the time of the initial radiotherapy showed less than 90 in 7 of 11 patients who had tumors involving the neurohypophyseal region, but the 4 patients who had solitary pineal tumors showed higher scores. Panhypopituitarism was observed in 9 patients with tumors involving the neurohypophyseal region. All patients are alive without disease, with a median follow-up period of 40 months. No in-field relapse was noted after the involved-field radiotherapy. One patient experienced a recurrence outside of the planning target volume. CONCLUSION: Decline of neurocognitive and endocrine functions were often seen in patients with tumors involving the hypophyseal region, but not in patients with solitary pineal germinoma before radiotherapy. Involved-field radiotherapy using 24 Gy is effective with the help of CT simulation and neoadjuvant chemotherapy.
Recent advances in the treatment of central nervous system germ cell tumors.
Explore the source record for details and available documents.
A rare case of acromegaly associated with pachydermoperiostosis.
Pachydermoperiostosis (PDP) is a rare syndrome manifested clinically by finger clubbing, extremity enlargement, hypertrophic skin changes, and periosteal bone formation. The pathogenesis of the disorder has not been clarified and few endocrine abnormalities were apparent. We report here a 58-year-old man with acromegaly associated with PDP, the features of clubbed fingers, coarse skin, and cutis verticis gyrata. Acromegaly due to GH-producing pituitary adenoma was confirmed in endocrinological and pathological studies.
Complete response of a large brain metastasis of renal cell cancer to interferon-alpha: case report.
BACKGROUND: Interferon-alpha (IFNalpha) is a drug widely used in the treatment of metastatic renal cell cancers, especially lung lesions. Successful treatment using IFNalpha for histologically proven brain metastasis has not been reported. CASE REPORT: A large pineal tumor was found in a 51-year-old man with renal cell cancer in the left kidney. The histological diagnosis of biopsied specimens was a brain metastasis from renal cell cancer. The patient was treated with intramuscular injections of IFNalpha. The brain metastasis gradually decreased in size and disappeared completely 6 months after the initial injection of IFNalpha. The IFNalpha therapy was continued for 9 months. Fifteen months later, no recurrence was evident on brain magnetic resonance imaging. CONCLUSION: This is an extremely rare case in which the long-term use of IFNalpha induced a complete response of a brain metastasis from renal cell cancer.
Small-field fractionated radiotherapy with or without stereotactic boost for vestibular schwannoma.
PURPOSE: To assess the efficacy and toxicity of small-field fractionated radiotherapy with or without stereotactic boost (SB) for vestibular schwannomas. METHODS AND MATERIALS: Thirty-nine patients with vestibular schwannoma were treated with irradiation between March 1991 and February 1996. Extra-meatal tumor diameters were under 30 mm. Thirty-three patients received small-field fractionated radiotherapy followed by SB. Basic dose schedule was 44 Gy in 22 fractions over 5 1/2 weeks plus 4 Gy in one session. Six patients received small-field fractionated radiotherapy only (40-44 Gy in 20-22 fractions over 5-5 1/2 weeks or 36 Gy in 20 fractions over 5 weeks).dash;p > RESULTS: Follow-up ranged from 6 to 69 months (median, 24 months). Tumors decreased in size in 13 cases (33%), were unchanged in 25 (64%), and increased in one (3%). The actuarial 2-year tumor control rate was 97%. Fifteen patients had useful hearing (Gardner-Robertson class 1-2) and 25 patients had testable hearing (class 1-4) before irradiation. The 2-year actuarial rates of useful hearing preservation (free of deterioration from class 1-2 to class 3-5) were 78%. The 2-year actuarial rates of any testable hearing preservation (free of deterioration from class 1-4 to class 5) were 96%. No permanent facial and trigeminal neuropathy developed after irradiation. The 2-year actuarial incidences of facial and trigeminal neuropathies were 8% and 16%, respectively. CONCLUSIONS: Small-field fractionated radiotherapy with or without SB provides excellent short-term local control and a relatively low incidence of complications for vestibular schwannoma, although further follow-up is necessary to evaluate the long-term results.
Dysplastic gangliocytoma (Lhermitte-Duclos disease) associated with Cowden disease: report of a case and review of the literature for the genetic relationship between the two diseases.
We report a case of dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos disease, LDD). The patient also had cutaneous and mucosal hamartomas, adenomatous goiter, bilateral breast tumors, and gastrointestinal polyposis, indicating the diagnosis of Cowden disease (CD), the familial hamartoma syndrome. This was a rare sporadic case without any family history of CD, though CD is considered to be an autosomal dominant hereditary disease. Based on a thorough review of the previously reported cases, it is reasonable to consider that CD is inherited in autosomal dominant fashion through a CD gene (PTEN) containing a germline mutation, and that the occurrence of LDD is predicted on an additional somatic hit on the remaining normal CD allele or another unknown gene.
Diagnosis of spinal cord ependymoma and astrocytic tumours with magnetic resonance imaging.
Ependymoma and astrocytic tumours, both originating from the glial tissue, constitute the majority of intramedullary spinal cord tumours. The purpose of this study is to evaluate the diagnostic ability of magnetic resonance imaging (MRI) in these two types of intramedullary spinal cord tumours. MRI findings of 17 ependymomas and 11 astrocytic tumours of the spinal cord were reviewed. Pre-contrast T(1)-weighted images revealed abnormal enlargement of the spinal cord in all cases. Peritumoural cyst formation was noted in 14 ependymomas (82%) and four astrocytic tumours (36%). Evidence of haemorrhage was identified in five (29%) ependymomas and one (9%) astrocytic tumour. Gadolinium-MRI (Gd-MRI) revealed marked enhancement in 11 ependymomas (65%), while six ependymomas showed irregular, partial or no enhancement. Five of these six ependymomas had evidence of prior haemorrhage. Eight astrocytic tumours (73%) were enhanced on Gd-MRI and the pattern of enhancement was more irregular or partial than that of ependymomas. Two pilocytic astrocytomas showed marked ring-like enhancement. In conclusion, detection of haemorrhage and Gd-MRI will help to differentiate these two types of tumours. Further study will be needed to elucidate the relationship between the histological subtypes of the tumours and MRI findings. Copyright 1999 Harcourt Publishers Ltd.
A lateral transzygomatic-transtemporal approach to the infratemporal fossa: technical note for mobilization of the second and third branches of the trigeminal nerve.
This report describes an alternative approach to the infratemporal fossa lesions through a lateral zygomato-temporal craniotemy, which modifies the extradural temporopolar technique for cavernous sinus surgery. First, an L-shaped osteotomy of the zygoma from the frontozygomatic suture attaching the zygomatre arch and low positioned temporal cramotomy are made. Through this zygomato-temporal craniotomy and orbitotemporal drilling, leaving the lateral orbital rim and orbital roof intact, skeletonization of the foramens rotundum and ovale are carried out. The key element of this infratemporal exposure is the dissection and mobilization of the trigeminal nerve, trigeminal second branch rostrally, and the third branch caudally, which facilitates a wide exposure of the infratemporal fossa with preserving trigeminal function. The corridor between the mobilized trigeminal branches provides direct access to the lateral and medial pterygoid plate, internal maxillary artery, sphenoid and maxillary sinuses, maxilla and, finally, the parapharyngeal area. Our experiences have demonstrated that this lateral transzygomatic-transtemporal exposure is satisfactory for use with infratemporal fossa tumors. This approach has an advantage for cranial-base exposure with decreased risks of cosmetic deformity and of trigeminal nerve dysfunction.
Extended Transsphenoidal Approach with Sigma-shape Osteotomy of the Maxilla: Technical Note.
The traditional sublabial transsphenoidal approach offers a limited operative field. This report describes a simple surgical technique to widen the sublabial transsphenoidal window to access the midline lesions from the planum sphenoidale to the lower clivus. This technique was developed on the basis of clinical experience and on data obtained by cadaveric dissection study. Following a sublabial incision and separation of the bilateral septal mucosa, a small Sigma-shape osteotomy of the maxilla, including the anterior nasal spine, was performed with a surgical saw. The width of the entrance to the nasal cavity ranged from 32 to 38 mm. Although the plexus of the anterior superior alveolar nerve was partially cut, our clinical experience revealed no significant sensory loss of the incisors after the Sigma-shape osteotomy. The nasal orests of the maxilla and palatine bone were drilled out, and the roof of the nasopharynx was then incised to expose the lower clival bone. Although extradural sellar or clival lesions were the focus of this approach, the intradural anatomical structures examined by cadaveric study were presented. The extended transsphenoidal approach with Sigma-shape osteotomy of the maxilla is a simple technique and provides widened access to the sellar and clival regions.
Salvage therapy for recurrent germinomas in the central nervous system.
This report presents the results of salvage therapy for 15 recurrent germinomas. The first recurrence occurred at a median of 37 months (range 6-122 months) after primary therapy. By the median follow-up period of 57 months after the first recurrence, seven of the 15 patients had died of the recurrent disease. Eleven of 15 patients who had been treated with reirradiation once achieved a complete response. Of these 11 patients, six had a second recurrence and two developed disabling radiation necrosis. Six of the 15 patients received a platinum-based chemotherapy and they also achieved a complete response. However, the remissions after chemotherapy alone were not durable. Three of the six patients received an additional low-dose (20-24 Gy) of irradiation following the chemotherapy and remained tumour-free with a performance status of more than 70%. Overall, the recurrent germinomas were consistently responsive to salvage radiation therapy and chemotherapy. However, just reirradiation or platinum-based chemotherapy alone was not sufficient to prevent a further recurrence. A low-dose of radiation therapy following chemotherapy is therefore recommended.
Roles of the functional loss of p53 and other genes in astrocytoma tumorigenesis and progression.
Loss of function of the p53 tumor suppressor gene due to mutation occurs early in astrocytoma tumorigenesis in about 30-40% of cases. This is believed to confer a growth advantage to the cells, allowing them to clonally expand due to loss of the p53-controlled G1 checkpoint and apoptosis. Genetic instability due to the impaired ability of p53 to mediate DNA damage repair further facilitates the acquisition of new genetic abnormalities, leading to malignant progression of an astrocytoma into anaplastic astrocytoma. This is reflected by a high rate of p53 mutation (60-70%) in anaplastic astrocytomas. The cell cycle control gets further compromised in astrocytoma by alterations in one of the G1/S transition control genes, either loss of the p16/CDKN2 or RB genes or amplification of the cyclin D gene. The final progression process leading to glioblastoma multiforme seems to need additional genetic abnormalities in the long arm of chromosome 10; one of which is deletion and/or functional loss of the PTEN/MMAC1 gene. Glioblastomas also occur as primary (de novo) lesions in patients of older age, without p53 gene loss but with amplification of the epidermal growth factor receptor (EGFR) genes. In contrast to the secondary glioblastomas that evolve from astrocytoma cells with p53 mutations in younger patients, primary glioblastomas seem to be resistant to radiation therapy and thus show a poorer prognosis. The evaluation and design of therapeutic modalities aimed at preventing malignant progression of astrocytomas and glioblastomas should now be based on stratifying patients with astrocytic tumors according to their genetic diagnosis.