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Biomedical subjects

Y Kimata

Publications and source records attributed to Y Kimata.

At least 37 records · Page 2Linked to original sources
PubMed1999

Anterolateral thigh flap for abdominal wall reconstruction.

The free or pedicled anterolateral thigh flap was introduced for the reconstruction of large abdominal wall defects. This flap is superior to the tensor fasciae latae musculocutaneous flap in several respects. These include the wide, reliable skin territory (which can reach the level of the knee) and the long pedicle. Therefore, a pedicled anterolateral thigh flap with reliable blood circulation can easily be positioned above the umbilicus. In addition, the free anterolateral thigh flap has greater freedom of orientation and can be used to repair larger abdominal wall defects than can the tensor fasciae latae flap. Seven patients in whom abdominal wall defects had been reconstructed with pedicled or free anterolateral thigh flaps were reviewed. Their average age was 47.1 years (range, 21 to 74 years), and the average follow-up period was 10.7 months (range, 2 to 21 months). The size of the abdominal wall defects ranged from 12 x 12 cm to 18 x 24 cm, and the size of the transferred flap ranged from 10 x 20 cm to 20 x 20 cm. Three flaps were pedicled and four were free, of which three incorporated the tensor fasciae latae flap. All flaps survived completely, and no postoperative abdominal hernias developed. Despite some variations in vascular anatomy and technical difficulties in elevating the anterolateral thigh flap, the authors conclude that the pedicled or free anterolateral thigh flap is superior to the tensor fasciae latae flap for reconstruction of large abdominal wall defects.

Abdominal Muscles↗
PubMed1999

Comparison of innervated and noninnervated free flaps in oral reconstruction.

Thirteen patients who had undergone ablative surgery for advanced squamous cell carcinoma in which more than half of the tongue had been resected underwent reconstruction in which the cutaneous nerve of a free flap was anastomosed to the stump of the transected lingual nerve. Eight of the patients underwent reconstruction with an innervated anterolateral thigh flap and five patients underwent reconstruction with an innervated rectus abdominis musculocutaneous flap. Sensory recovery of the flap at least 6 months postoperatively was compared in these 13 patients and in 16 additional patients who received noninnervated versions of the same flaps for the same defect. The degree of sensory recovery of innervated thigh flaps was significantly greater than that of noninnervated ones in all modalities and that of innervated rectus abdominis flaps was also greater than that of noninnervated flaps, except for hot and cold perception. These results indicate that sensory regrowth occurs in most areas through the surgically created pathways. However, results of Semmes-Weinstein testing showed that recovery did not reach the level of protective sensation in either type of innervated flap. Although these findings must be followed by additional objective and functional tests and the need for sensory reeducation should be considered, this simple operative procedure can improve postoperative intraoral function and should be attempted whenever possible after ablative surgery.

Abdominal Muscles↗
PubMed1999

Mutation of the yeast epsilon-COP gene ANU2 causes abnormal nuclear morphology and defects in intracellular vesicular transport.

Previously we reported an original method of visualizing the shape of yeast nuclei by the expression of green fluorescent protein (GFP)-tagged Xenopus nucleoplasmin in Saccharomyces cerevisiae. To identify components that determine nuclear structure, we searched for mutants exhibiting abnormal nuclear morphology from a collection of temperature-sensitive yeast strains expressing GFP-tagged nucleoplasmin. Four anu mutant strains (anu1-1, 2-1, 3-1 and 4-1; ANU=abnormal nuclear morphology) that exhibited strikingly different nuclear morphologies at the restrictive temperature as compared to the wild-type were isolated. The nuclei of these mutants were irregularly shaped and often consisted of multiple lobes. ANU1, 3 and 4 were found to encode known factors Sec24p, Sec13p and Sec18p, respectively, all of which are involved in the formation or fusion of intracellular membrane vesicles of protein transport between the endoplasmic reticulum (ER) and the Golgi apparatus. On the other hand, ANU2 was not well characterized. Disruption of ANU2 (delta anu2) was not lethal but conferred temperature-sensitivity for growth. Electron microscopic analysis of anu2-1 cells revealed not only the abnormal nuclear morphology but also excessive accumulation of ER membranes. In addition, both anu2-1 and delta anu2 cells were defective in protein transport between the ER and the Golgi, suggesting that Anu2p has an important role in vesicular transport in the early secretory pathway. Here we show that ANU2 encodes a 34 kDa polypeptide, which shares a 20% sequence identity with the mammalian epsilon-COP. Our results suggest that Anu2p is the yeast homologue of mammalian epsilon-COP and the abrupt accumulation of the ER membrane caused by a blockage of the early protein transport pathway leads to alteration of nuclear morphology of the budding yeast cells.

Amino Acid Sequence↗
PubMed1998

Loss of Hsp70-Hsp40 chaperone activity causes abnormal nuclear distribution and aberrant microtubule formation in M-phase of Saccharomyces cerevisiae.

The 70-kDa heat shock proteins, hsp70, are highly conserved among both prokaryotes and eukaryotes, and function as chaperones in diverse cellular processes. To elucidate the function of the yeast cytosolic hsp70 Ssa1p in vivo, we characterized a Saccharomyces cerevisiae ssa1 temperature-sensitive mutant (ssa1-134). After shifting to the restrictive temperature (37 degreesC), ssa1-134 mutant cells showed abnormal distribution of nuclei and accumulated as large-budded cells with a 2 N DNA content. We observed more prominent mutant phenotypes using nocodazole-synchronized cells: when cells were incubated at the restrictive temperature following nocodazole treatment, viability was rapidly lost and abnormal arrays of bent microtubules were formed. Chemical cross-linking and immunoprecipitation analyses revealed that the interaction of mutant Ssa1p with Ydj1p (cytosolic DnaJ homologue in yeast) was much weaker compared with wild-type Ssa1p. These results suggest that Ssa1p and Ydj1p chaperone activities play important roles in the regulation of microtubule formation in M phase. In support of this idea, a ydj1 null mutant at the restrictive temperature was found to exhibit more prominent phenotypes than ssa1-134. Furthermore, both ssa1-134 and ydj1 null mutant cells exhibited greater sensitivity to anti-microtubule drugs. Finally, the observation that SSA1 and YDJ1 interact genetically with a gamma-tubulin, TUB4, supports the idea that they play a role in the regulation of microtubule formation.

Adenosine Triphosphatases↗
PubMed1998

A new concept and technique for reconstruction of the lower pharyngeal space using the free jejunal graft.

OBJECTIVE: To report on a new concept and simple operative procedure to conform the diameter of the oral end of free jejunal grafts to that of pharyngeal defects for reconstruction of the lower pharyngeal space. DESIGN AND METHODS: A preliminary study showed that the jejunum is supplied by a highly vascular network and that longitudinal paramesenteric incisions can be made without disturbing the blood supply of the jejunum. We then developed the following operative procedure. The position of the highest point of the pharyngeal defect and the site of the recipient vessels are determined. The free jejunal graft is positioned with its mesentery in correspondence with the location of the recipient vessels. The position of a longitudinal incision 180 degrees to the highest point of the defect is then determined. After the oral border of the jejunum is opened with scissors, a pharyngojejunal end-to-end anastomosis is performed. PATIENTS: Eighteen patients with defects of the lower pharyngeal space after cancer treatment. RESULTS: We transferred jejunal grafts in 18 patients using this operative procedure. In 7 of these patients, paramesenteric incisions were made. The lengths of the incisions ranged from 2 to 8 cm. Transfer was successful in all 18 patients. Postoperative leakage occurred in 1 patient in whom an antimesenteric incision had been made; however, a fistula did not develop. CONCLUSIONS: Our method allows defects of the lower pharyngeal space to be reconstructed with end-to-end anastomosis of free jejunal grafts regardless of the location of the defect or of recipient vessels. This method is simple and appropriate for correcting large pharyngeal defects.

Adult↗
PubMed1998

Second toe plantar flap for partial finger reconstruction.

Utilizing the tissue obtained from the plantar surface (metatarsophalangeal-distal interphalangeal region) of the second toe is an ideal procedure for reconstruction of partial finger tissue defects. The major advantage of this method is that it provides satisfactory aesthetic and functional improvement at the recipient site: furthermore, good results from the aesthetic point of view and minimum morbidity at the donor site are obtained. Our procedure utilizes the free neurovascular skin flap (second toe plantar flap) and full-thickness skin graft. As for the free flap, artery and nerve are obtained from the plantar neurovascular bundle and vein from the dorsal or plantar vein. All cases reconstructed with this procedure revealed satisfactory sensory restoration and aesthetic appearance. The donor sites also revealed no contracture and visible scar. In this paper, we discuss the application of this procedure for finger tissue reconstruction.

Child, Preschool↗
PubMed1998

Anatomic variations and technical problems of the anterolateral thigh flap: a report of 74 cases.

We have transferred 74 free or pedicled anterolateral thigh flaps, including those combined with other flaps, for reconstruction of various types of defects. We report several anatomic variations of the lateral circumflex arterial system and discuss some technical problems with this flap. Septocutaneous perforators were found in 28 of 74 cases (37.8 percent), and no perforators were found in 4 cases (5.4 percent). In the 70 cases with perforators, 171 tiny cutaneous perforators (an average of 2.31 per case) were found. Musculocutaneous perforators (81.9 percent) were much more common than septocutaneous perforators (18.1 percent). Perforators were concentrated near the midpoint of the lateral thigh, and the selection of perforators as nutrient vessels for the anterolateral thigh flap was related to the length of the pedicle and the thickness of the skin flap. Anatomic variations of the branching pattern of perforators were classified into eight types. Flaps with perforators that arise directly from the profunda femoris artery are difficult to combine with other free flaps. Because the perforators are extremely small and tend to thrombose soon after congestion develops, these flaps are difficult to salvage with recirculation surgery. Therefore, several perforators should be included with the flap, if possible. The descending artery of the lateral circumflex femoral artery was always accompanied by two veins with different back-flow strengths. Therefore, veins for microsurgical anastomosis must be chosen carefully. Because it is nourished by several perforators arising from the descending artery, the vastus lateralis muscle can be combined with the anterolateral thigh flap. However, splitting the muscle longitudinally without harvesting its blood supply is complicated because its fibers are oblique. The rectus femoris muscle can also be combined with the anterolateral thigh flap, but its pedicle is short and its origin is very near the site of anastomosis. When the anterolateral thigh flap is combined with the tensor fasciae latae musculocutaneous flap, the large skin area of the lateral part of thigh can be transferred to repair the massive defects. The anterolateral thigh flap has many advantages and can be used to reconstruct many types of defect. However, anatomic variations must be considered if the flap is to be used safely and reliably.

Adolescent↗
PubMed1997

A novel mutation which enhances the fluorescence of green fluorescent protein at high temperatures.

Green fluorescent protein (GFP) from Aequorea victoria is widely used as a marker of gene expression and protein localization in living cells from prokaryotes to eukaryotes. However, the total fluorescent signal from wild-type GFP is very weak when expressed in cells cultured at 37 degrees C compared to 30 degrees C or below. This characteristic makes GFP poorly suited to use as a marker in mammalian cells. Here we describe a new variant of GFP which carries a substitution of Ser147 to Pro (S147P GFP) and which emits a stronger fluorescent signal than the wild-type GFP at high temperature. When S147P is combined with the Ser65 to Thr mutation (S65T GFP), the resulting double mutant emits fluorescence which is several-fold stronger than GFP with a single S65T modification in both bacterial or mammalian cells. This S147P mutation should be useful for constructing new GFP variants which stably emit strong fluorescence at a wide range of culturing temperatures.

Fluorescence↗
PubMed1997

Versatility of the free anterolateral thigh flap for reconstruction of head and neck defects.

OBJECTIVE: The anterolateral thigh flap has many advantages in head and neck reconstruction. However, it has not yet come into widespread use because of the anatomic variations of its perforators. Herein, we describe a safe operative technique related to the patterns of the perforators and discuss its wide versatility. SETTING: A national cancer center hospital. PATIENTS: Thirty-eight anterolateral thigh flaps were transferred. Confirmation and dissection of the flap pedicle were simultaneously performed with tumor resection. The design and elevation of the flap were carried out immediately after the tumor resection was completed. RESULTS: From the study of the anatomic variations of the perforators, septocutaneous patterns were recognized in 10 cases (26.3%) and musculocutaneous patterns in 28 cases (73.7%). All flaps were easily and safely elevated with our techniques. Thirty-six flaps survived. Partial necrosis was noted owing to excessive thinning procedure in one patient and total necrosis was noted owing to venous thrombosis at the anastomosis part in another patient. CONCLUSIONS: We found that the anterolateral thigh flap has numerous advantages. It is possible to perform the flap elevation and the tumor resection simultaneously. The flap is generally thin and is suitable for reconstruction of intraoral defects. Combined flaps with neighboring tissues and other, distant flaps can be used. Furthermore, since our technique minimizes the problems of confirmation and dissection of the perforators, we conclude that this flap can be successfully used to repair a variety of large defects of the head and neck.

Adult↗
PubMed1997

Saccharomyces cerevisiae KAR2 (BiP) gene expression is induced by loss of cytosolic HSP70/Ssa1p through a heat shock element-mediated pathway.

A family of highly-conserved 70 kDa stress proteins is localized in various intracellular compartments of Saccharomyces cerevisiae. Their gene expression is specifically and/or sometimes cooperatively regulated at the transcriptional level by cis-acting elements found in their respective promoters. Here, we find that depletion of cytosolic Ssa1p induced BiP(Kar2p) in the endoplasmic reticulum at the transcriptional level. By analyzing internal deletion mutants of the KAR2 promoter, we determined that the heat shock element (HSE) is necessary for KAR2 gene induction in response to the depletion of Ssa1p. Furthermore, either the KAR2HSE or SSA1HSE is sufficient for gene activation, as assayed using HSE-CYC1-lacZ fusion reporter plasmids. Finally, temperature-sensitive ssa1 mutants transformed with an HSE-CYC1-lacZ fusion vector exhibited strong induction of beta-galactosidase activity when shifted to a restrictive temperature. These results show that loss of functional Ssa1p from the cytosol up-regulates KAR2 gene expression through an HSE-mediated pathway and also support the idea that SSA1 gene expression is autoregulated.

Adenosine Triphosphatases↗
PubMed1997

A nitrate-inducible ferredoxin in maize roots. Genomic organization and differential expression of two nonphotosynthetic ferredoxin isoproteins.

We have identified and characterized a nitrate-inducible ferredoxin (Fd) in maize (Zea mays L.) roots by structural analysis of the purified protein and by cloning of its cDNA and gene. In maize Fd isoproteins are encoded by a small multigene family, and the nitrate-inducible Fd was identified as a novel isoprotein, designated Fd VI, which differed from an Fd I to Fd V identified to date. In the roots of seedlings cultured without nitrate, Fd VI was undetectable. However, during the induction of the capacity for nitrate assimilation, the amount of Fd VI increased markedly within 24 h. Concurrently, the level of transcript for Fd VI increased, but more quickly, reaching a maximal level within 2 h with kinetics similar to those of nitrite reductase and Fd-NADP+ reductase. Fd III was constitutively expressed in roots, and no such changes at the protein and mRNA levels were observed during the nitrate induction. In the 5' flanking region of the gene for Fd VI only, we identified NIT-2 motifs, which are widely found in genes for enzymes related to nitrogen metabolism. These data indicate that Fd VI is co-induced with the previously characterized enzymes involved in nitrate assimilation, and they suggest that the novel Fd isoprotein, distinct from the constitutively expressed Fd, might play an important role as an electron carrier from NADPH to nitrite reductase and other Fd-dependent enzymes in root plastids.

Amino Acid Sequence↗
PubMed1995

Role of Thr-252 in cytochrome P450cam: a study with unnatural amino acid mutagenesis.

Replacement of Thr-252 in the active center of cytochrome P450cam with a non-hydroxy amino acid residue such as Ala and Val by conventional site-directed mutagenesis converted this monooxygenase to an NADH oxidase (Imai, M. et al. Proc. Natl. Sci. U. S. A. 86, 7823-7827, 1989). In this study, a mutant enzyme with a methoxy group in place of the hydroxy group of Thr-252 (OMe-mutant) was synthesized by the method of unnatural amino acid mutagenesis (Noren, C. J. et al., Science 244, 182-188, 1989). Unlike other site-directed mutants without a hydroxy group at the position, the OMe-mutant retained a considerably high monooxygenase activity, yielding a stoichiometric amount of 5-exo-hydroxycamphor to that of the oxygen consumed. Thus a free hydroxy group at this position is not an indispensable requisite for the monooxygenase to cleave the O-O bond of molecular O2 as previously proposed.

Alanine↗
PubMed1995

Keloid formation after surgery for release of polysyndactyly of the feet in a child.

Keloid formation on the hands and the feet is very rare but should always be anticipated as a possible complication after surgery. Failure to recognise the potential for keloid may result in a severe deformity that is functionally and cosmetically undesirable. We report severe keloid formation after simple release of polysyndactyly of the feet of a 2-year-old child.

Female↗
PubMed1995

Thermosensitivity of green fluorescent protein fluorescence utilized to reveal novel nuclear-like compartments in a mutant nucleoporin NSP1.

Tagging proteins with the green fluorescent protein (GFP) from Aequorea victoria is a good means of analyzing protein localization in living cells. Nevertheless, GFP and a chimeric protein, GFP-nucleoplasmin, expressed in Saccharomyces cerevisiae were less fluorescent at high culture temperatures. Proteins synthesized at a low temperature retained their fluorescence despite a shift to a higher temperature. Hence, when a temperature-sensitive nsp1 mutant expressing GFP-nucleoplasmin was cultured at 23 degrees C and then shifted to 35 degrees C, we were able to exclusively monitor the localization of the protein synthesized prior to the temperature shift. This protein accumulated in novel nuclear-like compartments devoid of DNA.

Amino Acid Sequence↗
PubMed1995

Follow-up study of patients treated for ingrown nails with the nail matrix phenolization method.

In the past 7 years, a total of 537 ingrown nail lesions were treated with the nail matrix phenolization method (NMP). A study was performed based on follow-up examinations and a questionnaire survey regarding recurrence rate, degree severity, duration of postoperative pain, and other relevant factors. The major advantages of the NMP revealed by our study were: (1) The surgical procedure is easy to perform and does not require specialized equipment; (2) total time requirement for surgery is minimal; (3) the operation can be performed in the presence of a concomitant infection; (4) the recurrence rate is low (1.1%); and (5) postoperative pain and postoperative bed rest is minimized. These results indicate that NMP is an extremely effective method for treatment of ingrown nails.

Adolescent↗