Biomedical subjects

Yoshihiro Mizutani

Publications and source records attributed to Yoshihiro Mizutani.

11 recordsLinked to original sources

PubMed2006

Thermal injury caused by chandelier fiber probe.

PURPOSE: To investigate thermal changes produced by a chandelier fiber probe (CFP). DESIGN: Interventional single case report and laboratory investigation. METHODS: When CFP was used for 25-gauge vitrectomy, an abnormal odor was emitted, and the CFP was instantly removed. To investigate this incident, the thermal change produced by the CFP was measured in air by means of an infrared sensor. Porcine Tenon capsular tissue was used to reproduce the intraoperative phenomenon. RESULTS: In our patient, the CFP tip melted, but this did not affect visual function. In the experiment, the uncoated CFP reached 49 C (120 F) at maximum illumination. When porcine Tenon capsular tissue was attached to the CFP tip, a temperature of 144 C (291 F) was reached at 50% of maximum illumination, and over 201 C (394 F) at 75%. The tip melted under these conditions. CONCLUSIONS: At present, we avoid the use of CFP during air exchange. This potential hazard of the CFP needs to be addressed.

Body Temperature↗

PubMed2006

25-gauge scleral tunnel transconjunctival vitrectomy.

PURPOSE: To compare the intraocular fluid leakage rate between 25-gauge (25G) transconjunctival vitrectomy with scleral tunnels and standard 25G transconjunctival vitrectomy. DESIGN: Single-center, retrospective, interventional case series. METHODS: Transconjunctival vitrectomies were conducted by the use of only 25G instruments with peripheral vitrectomy. Standard 25G vitrectomy was conducted in 542 eyes and 25G vitrectomy with scleral tunnels in 337 eyes. The scleral tunnel was created by inserting trocars at an oblique angle. RESULTS: The intraocular fluid leakage rate was significantly lower (Fisher exact probability test: P < .0001) when scleral tunnels were used in 25G vitrectomy (1%, five of 337 eyes) compared with standard 25G vitrectomy (9%, 50 of 542 eyes). The wound leakage rate was significantly lower when using (rather than not) scleral tunnels in 25G vitrectomy, both without air-gas (P = .0258) and with air exchange (P = .0007). CONCLUSION: The use of scleral tunnels in 25G transconjunctival vitrectomy reduces the frequency of wound leakage even when the peripheral vitreous is removed.

Adolescent↗

PubMed2006

Study of association between hypertensive disorders of pregnancy and the human coagulation factor XI gene.

OBJECTIVE: Hypertensive disorders of pregnancy (HDP) are among the most common and serious complications of pregnancy. Persuasive evidence implicaties genetic factors in the genesis of HDP. The aim of the present study was to assess the association between single-nucleotide polymorphisms (SNPs) in the human coagulation factor XI (F11) gene and HDP, by conducting a haplotype-based case-control study. METHODS: We chose 3 SNPs (rs925453, rs925451, and rs12500151) in the human F11 gene as genetic markers. We then conducted an association study with 77 HDP patients and 154 age-matched non-HDP subjects. RESULTS: The frequency of rs925453 genotypes significantly differed between the two groups. The frequency of the T-G-G haplotype was significantly higher in the HDP group than in the non-HDP group (p = 0.0002). CONCLUSIONS: The T allele of rs925453 and the T-G-G haplotype appear to be useful genetic markers of HDP.

Adolescent↗

PubMed2005

Association study between the human Renin gene and preeclampsia.

OBJECTIVE: We recently reported on a missense mutation in exon 9 of the human renin gene (G1051A) that may affect the functioning of this enzyme, and is associated with essential hypertension. The aim of the present study is to assess the association between the genotypes of this missense mutation in the renin gene and preeclampsia (PE) via a case-control study. METHODS: DNA was extracted from peripheral blood leukocytes, and genotyping of G1051A was performed in 117 PE patients and in 171 non-PE controls. RESULTS: The frequency of genotypes for G1051A was not significantly different between the two groups. The frequency of the A1051 allele was also not significantly different between PE patients (52.6%) and non-PE controls (50.6%). CONCLUSIONS: The missense mutation G1051A in the human renin gene is not associated with PE.

Adolescent↗

PubMed2004

Association study using single nucleotide polymorphisms in the estrogen receptor beta (ESR2) gene for preeclampsia.

The pathophysiology of preeclampsia (PE) remains uncertain despite many research efforts. Actual hypotheses seek to explain the vascular damage that characterizes the disease. Recently, it was reported that the mouse disrupted estrogen receptor beta (ESR2) gene was associated with abnormal vascular function and hypertension. Moreover, some investigators have reported that subjects with a family history of hypertension have a statistically significant increased risk for PE. Thus, it is thought that the pathophysiology of PE overlaps that for hypertension. The aim of the present study was to investigate the relationships between single nucleotide polymorphisms (SNPs) in the human ESR2 gene and PE in Japanese subjects, and to assess the involvement of a family history of hypertension in these relationships. Based on a database search on the web site of the National Center of Biotechnology Information (NCBI), we chose four SNPs in the human ESR2 gene, and performed an association study in 84 PE patients and 160 age-matched non-PE subjects. The overall distribution in each SNP did not differ significantly between the two groups. However, after dividing the groups into subjects with and without a family history of hypertension, the allelic distribution of one of the SNPs (rs928554) revealed a positive association. Thus, a possible mutation linked to a SNP may prescribe a genetic predisposition for patients with a family history of hypertension in PE.

Adolescent↗

PubMed2003

Modified gluteus maximus V-Y advancement flap for reconstruction of perineal defects after resection of intrapelvic recurrent rectal cancer: report of a case.

Technical advances in myocutaneous flap preparation have resulted in primary reconstruction now being generally indicated for malignant tumors extensively infiltrating the pelvic cavity and perineum. Pelvic tumor resection can dramatically improve the health-related quality of life (QOL) of patients with locally recurrent rectal cancer complicated by infection and pain. However, the removal of a wide area of perineum by these two procedures often leaves a large dead space. A gluteal thigh muscle, rectus abdominis muscle, or pedicle myocutaneous flap is usually made to reconstruct such extensive perineal defects. The subject of this case report was a 76-year-old woman with recurrent rectal cancer in the pelvis after abdominoperineal resection. The large pelvic tumor, which was causing severe pain, was resected and the extensive perineal defects were reconstructed using a modified maximus V-Y advancement flap. The operating time was approximately 30 min, and the pain after surgery was much less severe. Moreover, she could walk the day after surgery and returned to normal daily life without requiring prolonged bed rest. No infection developed in the intrapelvic dead space postoperatively. This technique proved very useful for improving the patient's QOL.

Adenocarcinoma↗

PubMed2003

Haplotype analysis of the human renin gene and essential hypertension.

The human renin gene is an attractive candidate for involvement in the underlying cause of essential hypertension (EH). Despite extensive examination, the relation between the renin gene and hypertension remains unclear. The aims of the present study were to discover new genetic markers of EH and to investigate the relations between polymorphisms of the renin gene and EH in the Japanese. Using the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) method, we isolated 3 novel variants of the renin gene; a single nucleotide polymorphism (SNP) in intron 4 (T+17int4G), a variable number of tandem repeats (VNTR) polymorphism in intron 7, and a missense mutation in exon 9 (G1051A). We performed an association study with these polymorphisms in 212 patients with EH and 209 age-matched normotensive (NT) subjects. The frequency of genotypes VNTR and T+17int4G did not differ significantly between the 2 groups, whereas the overall distribution of G1051A was significantly different between EH and NT. Haplotype analysis revealed that the overall distribution of haplotypes differed significantly between the EH and NT groups. PRA levels in patients with EH with the G/G genotype were significantly higher than in subjects with EH with G/A and A/A genotypes. These data suggest that the missense mutation in exon 9 may affect the enzymatic function of renin and consequently may be involved in the etiology of hypertension.

Adult↗

PubMed2003

A novel variable number of tandem repeat polymorphism of the renin gene and essential hypertension.

The aims of the present study were to find new genetic markers of essential hypertension (EH) and to investigate relationships between EH and polymorphisms of the renin gene. Using single strand conformation polymorphism, we discovered a new variable number of tandem repeat (VNTR) polymorphism in intron 7 that is 18 bp upstream from the boundary with exon 8. Nucleotide sequencing revealed that this VNTR polymorphism is a tandem repeat of the 4-nucleotide sequence TCTG. There were 6 alleles of this VNTR polymorphism, ranging from 7 repeats to 12 repeats. We analyzed the association between EH and this VNTR polymorphism. There was no significant difference in the overall distribution of this VNTR polymorphism between the EH and normotensive subjects. In summary, we discovered a novel VNTR polymorphism in the renin gene, and this polymorphism was not associated with EH.

Adult↗

PubMed2002

A novel missense mutation of exon 3 in the type A human natriuretic peptide receptor gene: possible association with essential hypertension.

The natriuretic peptide (NP) family is involved in regulation of blood pressure and fluid volume. We recently characterized the exon/intron organization of the human type A NP receptor (hNPRA) gene. The aim of this study was to isolate the genetic markers according to the organization of this gene, and to study the association between this gene and essential hypertension. Using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis, we identified a novel missense mutation, M3411, consisting of a methionine (ATG) to isoleucine (ATC) substitution at nucleotide 1023 in exon 3. Computer-aided three-dimensional structural analysis suggested that M341 exists in the loop between two alpha-helices, and that the mutation may influence receptor activities by altering the conformation of the alpha-helices. We performed an association study of the mutation in 210 essential hypertension (EH) patients and 210 normotensive controls. The overall distribution of alleles was not significantly different between the control and EH groups. However, the C/C homozygous genotype was found only in the EH group. The ratio of plasma brain natriuretic peptide (BNP)/mean blood pressure of the C/C genotype was significantly higher than that of the G/G genotype or the G/C genotype. We conclude that the significance of homozygous M3411 mutation in exon 3 is worth investigating for its possible association with EH.

Adult↗

PubMedDate not supplied

Twenty-gauge Transconjunctival Vitrectomy.

PURPOSE: To describe a new 20-gauge transconjunctival vitrectomy procedure that we designed, to evaluate its usefulness, and to compare two different methods of use. METHODS: The records of 431 patients (433 eyes) who underwent 20-gauge transconjunctival vitrectomy at the Surugadai Hospital of Nihon University between March 2003 and January 2004 were studied retrospectively. In surgical method 1, 20-gauge wounds were made through the conjunctiva and sclera together. In surgical method 2, 20-gauge conjunctival openings were made 2 mm posterior to the sclerotomies. Absorbable sutures were used to stitch the scleral and conjunctival openings simultaneously in both methods. RESULTS: A 20-gauge transconjunctival vitrectomy has various benefits and is indicated for nearly all ocular diseases. Moreover, it is not limited by the intraocular instruments required. However, since cannulas were not placed in all ports, conjunctival edema occurred more easily with surgical method 2 owing to the leakage of perfusion fluid. CONCLUSIONS: This new 20-gauge transconjunctival vitrectomy procedure has various benefits and is indicated for nearly all ocular diseases. It is not limited by the intraocular instruments required.

Adult↗

PubMedDate not supplied

Expanded indications for 25-gauge transconjunctival vitrectomy.

PURPOSE: We conducted 25-gauge (25G) transconjunctival vitrectomy to treat patients with various ocular diseases, and examined the possibility of expanding the indications for this system through combined use with 20G devices when needed. METHODS: The records of 167 patients (169 eyes) who underwent vitrectomy in our hospital between April and June 2004 were studied. Vitrectomy had been conducted using the 20G or 25G transconjunctival vitrectomy system. RESULTS: In 7 of the 169 eyes (4%), the 20G system was initially selected. Vitrectomy could be performed using the 25G system alone in 150 eyes (89%), while 20G devices were used in combination with the 25G system in 12 (7%). None of the 25G scleral wounds were sutured, while all the 20G scleral wounds were sutured at the completion of surgery. Low intraocular tension was noted in 15 of 162 eyes (9%), but all these eyes recovered within 2 to 4 days. In two eyes with macular hole, retinal detachment occurred, but reattachment was achieved after reoperation. No extensive vitreoretinal hemorrhage or postoperative infection was observed. CONCLUSIONS: By combining the use of 20G devices, indications for the 25G system can be expanded. However, postoperative low ocular tension must be addressed by carefully considering surgical indications and prevention measures.

Adolescent↗