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Biomedical subjects

Y Kakizawa

Publications and source records attributed to Y Kakizawa.

At least 19 recordsLinked to original sources
PubMed2006

Telecontrolled micromanipulator system (NeuRobot) for minimally invasive neurosurgery.

BACKGROUND: To perform less invasive neurosurgery, a telecontrolled micromanipulator system has been developed and applied to clinical situations. Basic experiments for telesurgery have also been conducted. METHOD: A cadaver head was used to carry out surgical simulation of the opening of the sylvian fissure and third ventriculostomy. After obtaining permission from the Ethical Committee of Shinshu University School of Medicine, part of the recurrent meningioma in a 45-year-old man was removed. As basic experiment for telesurgery, surgical simulation was also conducted in a rat brain with the operating console transported to a hospital 40 km distant from the University. FINDINGS: Opening of the sylvian fissure and third ventriculostomy were accurately performed. Tumour removal in a patient with recurrent meningioma was safely achieved. Surgical simulation in the rat brain was accurately and correctly carried out, operated on from a hospital 40 km distant. CONCLUSIONS: The NeuRobot, telecontrolled micromanipulator system, can be used as a tool for less invasive neurosurgery.

Animals↗
PubMed2001

Low anterior interhemispheric approach--a narrow corridor to aneurysms of the anterior communicating artery.

BACKGROUND: Many approaches for clipping anterior communicating artery (ACoA) aneurysms are reported in the literature. We describe here a new approach called "low anterior interhemispheric approach" for clipping of ACoA aneurysms. MATERIALS AND METHODS: A low anterior interhemispheric approach utilizing a unilateral frontal craniotomy flap with minimal unilateral frontal lobe retraction was used in treating four patients harboring an unruptured ACoA aneurysm. The approach axis is directed to the ACoA area itself with minimal exposure to the anterior cerebral vessels. FINDINGS: In all patients, complete neck clipping was possible with minimal brain retraction, without vascular damage and preserved olfaction. INTERPRETATION: This approach is preferred on anatomical grounds for cases of unruptured small and medium sized ACoA aneurysms projecting anteriorly or posteriorly because the anterior communicating artery complex area can be fully visualized with minimal manipulation of the frontal lobes and anterior cerebral arteries.

Adult↗
PubMed2001

Glutathione-sensitive stabilization of block copolymer micelles composed of antisense DNA and thiolated poly(ethylene glycol)-block-poly(L-lysine): a potential carrier for systemic delivery of antisense DNA.

Glutathione (GSH)-sensitive stabilization of polyion complex (PIC) micelles entrapping antisense oligonucleotide (ODN) was achieved by the reversible cross-linking of the core through disulfide bonds, aiming at the development of a novel DNA carrier system for antisense therapy following systemic administration. Thiolated poly(ethylene glycol)-block-poly(L-lysine) (PEG-thioPLL) and ODN spontaneously associated to form the PIC micelles with the core cross-linked through disulfide bonds. The diameters of the cross-linked micelles were similar to those of the non-cross-linked micelles and were determined to be about 40 nm by light scattering measurements. The micelles have sufficient colloidal stability due to the PEG shell surrounding the core of the polyion complex composed of PLL and ODN. The polyanion exchange studies suggested that the dissociation of the micelles was suppressed through the core cross-linking. The stability of the ODN in the core cross-linked micelles against nuclease was appreciably increased compared to that of free ODN and that in the micelles without cross-linking. On the other hand, the micelles dissociated to release ODN in the presence of GSH at a concentration comparable to the intracellular environment, featuring the potential ability of this system for intracellular ODN delivery.

Cross-Linking Reagents↗
PubMed2001

How to make a three-dimensional surgical illustration of cerebral vessels with a personal computer: technical note.

OBJECTIVE: To introduce a method of making three-dimensional (3-D) illustrations of cerebral vessels with a personal computer. METHODS: We generated the 3-D images from only two views of conventional angiograms (anteroposterior and lateral views) with a personal computer, two commercial software programs, and an image scanner. RESULTS: This method was applied to 10 consecutive cases of cerebral aneurysms. 3-D images were made in a few hours, and they contributed to assessing vascular structures of an aneurysm complex. CONCLUSION: This method is useful for discussing surgical strategies preoperatively. Our method may be used in any facility where conventional angiography, personal computers, and 3-D software are available.

Cerebral Angiography↗
PubMed2000

Parameters for contralateral approach to ophthalmic segment aneurysms of the internal carotid artery.

OBJECTIVE: This study was undertaken to define more accurately the feasibility and indications of the contralateral pterional approach to ophthalmic segment aneurysms of the internal carotid artery (ICA). METHODS: Between 1995 and 1999, 46 patients with ophthalmic segment aneurysms of the ICA were surgically treated in our institution. Eleven of the 46 aneurysms were operated using the contralateral pterional approach. All aneurysms were successfully clipped without complications; three patients required bone resection around the aneurysm neck. We studied the 11 patients who were treated with the contralateral approach by defining six parameters to assess the feasibility of the approach and to predict the necessity for bone resection: 1) Parameter A, the distance between the anterior aspect of the optic chiasm and the limbus sphenoidale; 2) Parameter B, the distance between the bilateral optic nerves at the entrance to the optic canal; 3) Parameter C, the interrelation of the optic nerve and the ICA, expressed as a/b in which a is the length from the midline to the optic nerve and b is the length from the midline to the ICA; 4) Parameter D, the size of the aneurysm neck; 5) Parameter E, the direction of the aneurysm from the ICA wall on the anteroposterior angiogram; and 6) Parameter F, the distance from the medial side of the estimated distal dural ring to the proximal aneurysm neck on the lateral angiogram. RESULTS: Parameters A to F were 8.8 mm (range, 5.4-11.1 mm), 14.5 mm (range, 10.4-22.2 mm), 0.9 mm (range, 0.6-1.3 mm), and 3.0 mm (range, 2.3-4.7 mm), 5 to 160 degrees, and 1.3 mm (range, 0.3-2.4 mm), respectively. All patients had excellent operative outcomes without visual dysfunction. Three patients required drilling of the bone around the optic canal on the craniotomy side; bone drilling was not required when Parameter E was between 30 and 160 degrees and Parameter F was more than 1 mm. CONCLUSION: Parameters A to D are important for assessing the feasibility of the contralateral approach to ICA-ophthalmic segment aneurysms, and Parameters E and F are most useful for calculating the difficulty of this approach.

Aged↗
PubMed2000

Intentional body clipping of wide-necked basilar artery bifurcation aneurysms.

OBJECT: Neck clipping or coil embolization cannot always achieve complete neck obstruction in wide-necked basilar artery (BA) bifurcation aneurysms. Clipping of the aneurysm body, leaving a small aneurysm rest, is one clipping method used for this kind of aneurysm to maintain the patency of the posterior cerebral arteries and perforating vessels. However, the long-term efficacy of intentional body clipping has not been well investigated. The authors reviewed their experience with intentional body clipping of wide-necked BA bifurcation aneurysms to determine suitable clipping techniques and the long-term efficacy of the procedure. METHODS: Complete neck occlusion was abandoned and body clipping intentionally performed in 17 patients with BA bifurcation aneurysms; wrapping of the aneurysm rest was made in seven cases. There were 10 ruptured aneurysms (58.8%), and the size of the aneurysm was larger than 10 mm in 11 patients (64.7%). The width between the clip blades and the base of the aneurysm neck was 1 mm in 11 cases, 2 mm in four, and 3 mm in two. Favorable outcome (Glasgow Outcome Scale [GOS] Score 4 or 5) was obtained in 13 cases (76.5%) and unfavorable outcome (GOS Scores 1-3) in four cases (23.5%). Major causes of unfavorable outcome included injury to perforating arteries and major vessel occlusion following surgical manipulation, in addition to the primary damage caused by subarachnoid hemorrhage. Subarachnoid hemorrhage did not occur during a mean follow-up period of 7.4+/-5.6 years (range 0.7-18.1 years) after treatment. CONCLUSIONS: Intentional body clipping of wide-necked BA aneurysms proved to be effective to prevent subarachnoid hemorrhage, although injury to perforating arteries remains problematic. The choice of complete neck clipping or body clipping should be established early during the microsurgical procedure to reduce the risk of injury to perforating vessels.

Adult↗
PubMed2000

[Surgical treatments for 7 pituitary adenomas in multiple endocrine neoplasia type 1].

We analyzed 7 pituitary adenomas in patients with multiple endocrine neoplasia type 1 (MEN1). Their incidence was 1.6% among 450 patients with pituitary adenomas which had been treated surgically in our department between 1978 and 1999. The age, gender, symptoms, type of hormone secretion, pathological and operative findings in the MEN1 patients were not apparently different from those in the non-MEN1 patients. Incidence of non-functioning pituitary adenomas, however, was more frequently encountered in our series than that in previous reports among Caucasian people. One patient who had 5 previous operations for the MEN tumors died following postoperative subarachnoid hemorrhage. Four of the seven patients presented initial symptoms related to pituitary adenomas and increased serum Ca level was retrospectively recognized in three of the four at the time of treatment for the pituitary adenomas.

Adenoma↗
PubMed1999

[Clinical review of acute scrotum in children].

BACKGROUND: The acute scrotum in children frequently presents a diagnostic dilemma. The objective of this study is to review the experience of patients with acute scrotum in children. METHODS: From April 1986 until March 1998, we encountered 40 cases of acute scrotum in children less than 15 years old diagnosed by surgical exploration. RESULTS: Final diagnoses consisted of 14 patients with torsion of the spermatic cord (35%), 22 patients with torsion of the testicular appendage (55%), 3 patients with acute epididymitis (7.5%), and patient with a strangulated hernia (2.5%). Of 22 patients with torsion of the testicular appendage, which were the most frequent cause of acute scrotum, 20 had torsion of the testicular appendix and 2 had torsion of the epididymal appendix. The age distribution of the patients with torsion of the spermatic cord was biphasic, with the highest frequencies occurring in patients 2 years old and 14 years old. In contrast, the age distribution of patients with torsion of appendage showed a single peak incidence at 9 years of age. Those with epididymitis were younger than 2 years old. Of 14 cases of torsion of the spermatic cord, orchiectomy was performed in 6 cases (42.9%) because of testicular necrosis. CONCLUSION: Although surgical exploration is no longer necessary for all patients with torsion of the appendage, this review revealed that patients complaining of severe or persistent pain usually require surgery to diagnose and treat the problem.

Acute Disease↗
PubMed1999

[Giant cell tumor originating in the sphenoid bone: a case report].

The authors report a case of giant cell tumor originating in the sphenoid bone. A 29-year-old woman presented with headache and diplopia. Bilateral ophthalmoplegia developed and MRI showed rapid growth of the tumor in spite of transnasal removal and conventional radiation therapy. The second transnasal surgery was performed 3 weeks after completion of radiotherapy. The symptoms were relieved except for right abducens palsy. Chemotherapy with cisplatin and etoposide was started after the second operation. The patient regained full ocular movement several months after the operation. Clinical remission has continued for four years. We conclude that the combination of repeated operations in the initial phase of rapid tumor growth, irradiation and chemotherapy is important to achieve tumor control.

Adult↗
PubMed1994

Primary chemotherapy for children with rhabdomyosarcoma of the 'special pelvic' sites: is preservation of the bladder possible?

Twenty-one children with rhabdomyosarcoma involving the "special pelvic" sites, defined as such occurring in the bladder, prostate, vagina and uterus, were treated with primary surgery between 1969 and 1977, and with primary chemotherapy beginning in 1978. Among 11 patients in the latter group who were placed in Clinical Group III (according to the classification of the US Intergroup Rhabdomyosarcoma Study (IRS), six showed partial response (PR) and underwent tumorectomy by radical surgery an average of 6 months after the start of treatment, and three showed complete response (CR) and were treated with further chemotherapy in the hope that cystectomy could be avoided. However, in the latter group, the tumor recurred (39 months, 35 months, and 27 months later), and all eventually underwent total cystectomy. Seven of the nine long-term survivors underwent total cystectomy and have premanent urinary-cutaneous stomas. Two had tumor-free bladders, but function was impaired in one because of the effect of irradiation. Normal function was preserved in only one patient in the series, whose tumor was located at the dome of the bladder. To preserve bladder function in children with rhabdomyosarcoma in these sites, more effective forms of chemotherapy will be required.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

Intragenic homozygous deletion of the WT1 gene in Wilms' tumor.

One example of intragenic homozygous deletion of the WT1 gene on chromosome 11p13 was found after screening 42 samples of Wilms' tumor DNA from Japanese patients. After construction of a restriction map for the genomic sequence covering the 3' half of the gene, the deletion was analysed at the nucleotide sequence level. The deletion occurred in the patient's germline on his paternal chromosome, and most of the short arm of his maternal chromosome 11 was subsequently lost in the tumor. The size of the deletion was about 8 kb, removing exons 6 and 7 and resulting in premature termination. The deletion seemed to be created by recombination between short homologous sequences found in an Alu repeat, with a 16-bp duplication left at the junction. This case conforms to a two-hit model for the genesis of a certain group of tumors, and supports the hypothesis that WT1 is one of the recessive oncogenes responsible for Wilms' tumor.

Base Sequence↗
PubMed1991

Deoxyribonucleic acid and cytological detection of Y-containing cells in an XX hypospadiac boy with polyorchidism.

A hypospadiac boy with a hypoplastic penis and an apparent 46,XX karyotype in blood and testis cultures is described. Exploratory laparotomy and bilateral gonadal biopsy revealed the presence of 2 testes in the right and 1 in the left hemiscrotum, each of which only showed hypoplastic testicular tissues histologically. Uncultured testis smears showed Y chromatin in approximately 20% of the cells. Also, the Southern blot and polymerase chain reaction analyses detected a weak but distinct signal of Y chromosome-derived deoxyribonucleic acid sequences in the perineal skin but not in the blood lymphocytes. The results indicated that the boy had a small proportion of Y chromosome-containing cells in the form of mosaicism in limited tissues, such as the testes and perineal skin. This finding may have implications in the genesis of testes in some cases of XX patients, and true hermaphrodites or male pseudohermaphrodites with an apparent 46,XX karyotype. To our knowledge, this appears to be the first case of polyorchidism with an identified chromosome abnormality.

Blotting, Southern↗
PubMed1991

[A case of true phimosis with bilateral hydroureteronephrosis and bilateral vesicoureteral reflux].

A 12-year-old boy presented with nocturnal enuresis. He could not void in a stream and urine dropped out of the external urethral orifice. Physical examination revealed the stenosis of prepuce and balanoposthitis. An intravenous pyelogram and a cystogram showed bilateral hydroureteronephrosis and bilateral vesicoureteral reflux. He was diagnosed with severe true phimosis complicated with bilateral hydroureteronephrosis and bilateral vesicoureteral reflux. His balanopothitis was treated with antibiotics for a few days. Dorsal slit of prepuce and release of adhesion between glans and prepuce were subsequently performed. Four months after operation, an intravenous pyelogram revealed regression of hydronephrosis. Bilateral vesicoureteral reflux was not observed on the cystogram. The possibility of upper urinary tract involvement must be considered in patients with true phimosis and dysuria.

Bacterial Infections↗
PubMed1987

[Bone metastasis of malignant solid tumors in childhood].

A total of 452 cases of childhood malignant solid tumors were treated over the last twenty years at the National Children's Hospital. These included 175 cases of neuroblastoma, 64 cases of Wilms' tumor, 65 cases of malignant lymphoma, 45 cases of soft tissue sarcoma, 31 cases of hepatoma, 20 cases of malignant teratoma, 17 cases of testicular tumor, 7 cases of ovarian tumor and 28 cases of other forms of malignant solid tumor. Bone metastasis was observed in 62 of 175 cases of neuroblastoma, 3 of 64 cases of Wilms' tumor, one of 65 cases of malignant lymphoma, 4 of 45 cases of soft tissue sarcoma, one case of pulmonary blastoma and one case of osteogenic sarcoma, giving a total occurrence of bone metastasis in 72 of the 452 cases. The main sites of bone metastasis in neuroblastoma were the skull (61.4%), femur (56.8%), orbit (27.3%) and spine (22.7%). The average values of serum calcium and alkaline phosphatase activity showed no significant difference. The patients with bone metastasis were treated with a combination of radiation therapy and intensive chemotherapy, resulting in temporary improvement. The survival of patients with stage IV neuroblastoma with bone metastasis was worse than that of similar patients without bone metastasis.

Bone Neoplasms↗