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Biomedical subjects

H Takami

Publications and source records attributed to H Takami.

At least 19 recordsLinked to original sources

Role of arginine residues on the S4 segment of the Bacillus halodurans Na+ channel in voltage-sensing.

The one-domain voltage-gated sodium channel of Bacillus halodurans (NaChBac) is composed of six transmembrane segments (S1-S6) comprising a pore-forming region flanked by segments S5 and S6 and a voltage-sensing element composed of segment S4. To investigate the role of the S4 segment in NaChBac channel activation, we used the cysteine mutagenesis approach where the positive charges of single and multiple arginine (R) residues of the S4 segment were replaced by the neutrally charged amino acid cysteine (C). To determine whether it was the arginine residue itself or its positive charge that was involved in channel activation, arginine to lysine (R to K) mutations were constructed. Wild-type (WT) and mutant NaChBac channels were expressed in tsA201 cells and Na+ currents were recorded using the whole-cell configuration of the patch-clamp technique. The current/voltage (I-V) and conductance/voltage (G-V) relationships steady-state inactivation (h(infinity)) and recovery from inactivation were evaluated to determine the effects of the S4 mutations on the biophysical properties of the NaChBac channel. R to C on the S4 segment resulted in a slowing of both activation and inactivation kinetics. Charge neutralization of arginine residues mostly resulted in a shift toward more positive potentials of G-V and h(infinity) curves. The G-V curve shifts were associated with a decrease in slope, which may reflect a decrease in the gating charge involved in channel activation. Single neutralization of R114, R117, or R120 by C resulted in a very slow recovery from inactivation. Double neutralization of R111 and R129 confirmed the role of R111 in activation and suggested that R129 is most probably not part of the voltage sensor. Most of the R to K mutants retained WT-like current kinetics but exhibited an intermediate G-V curve, a steady-state inactivation shifted to more hyperpolarized potentials, and intermediate time constants of recovery from inactivation. This indicates that R, at several positions, plays an important role in channel activation. The data are consistent with the notion that the S4 is most probably the voltage sensor of the NaChBac channel and that both positive charges and the nature of the arginine residues are essential for channel activation.

Amino Acid Sequence↗

Comparative study of thyroidectomies. Endoscopic surgery versus conventional open surgery.

BACKGROUND: We have performed endoscopic thyroidectomy by an anterior chest approach and by an axillary approach. In this study, we evaluate the efficacy of these two types of endoscopic procedures and conventional open surgery. METHODS: Each procedure was performed in 15 patients. The degree of surgical invasiveness and the nature of patients' complaints after surgery were compared using results of the operation and a questionnaire. RESULTS: Although the mean operating time for the endoscopic procedure was significantly longer than for open surgery, there was no postoperative pain difference in the three groups. Three months after surgery, the incidence of swallowing discomfort was higher in the open surgery group than in endoscopic surgery group. All of the patients treated using the axillary approach were satisfied with the cosmetic results. However, three patients (20%) treated using the anterior chest approach and 11 patients (73%; p < 0.01) who underwent open surgery complained about the cosmetic results. CONCLUSIONS: The incidence of postoperative complaints after endoscopic surgery is significantly lower than after open surgery. Patients treated using the axillary approach can obtain cosmetic results superior to those achieved with other procedures.

Adenoma↗

Minimally invasive radioguided parathyroidectomy.

The recent development of radioguided parathyroidectomy has allowed parathyroidectomy to be quickly performed by a significantly less invasive procedure. Radioguided parathyroidectomy is also likely to decrease operation time, risk of complications, hospital stay, and the overall cost of patient care, result in a smaller scar and rapid, nearly pain-free recovery, and allow local anesthesia. Despite these apparent benefits, a case-control study showed no distinct advantages of employing intraoperative sestamibi identification during parathyroidectomy.

Humans↗

Intraoperative quick parathyroid hormone assay in the surgical management of hyperparathyroidism.

Intraoperative quick parathyroid hormone (QPTH) assay is claimed to prevent failure during parathyroidectomy for hyperparathyroidism. The causes of operative failure have included multiglandular disease, ectopic parathyroid glands, supernumerary parathyroid glands, errors in frozen section evaluations, and missed diagnosis. A QPTH assay has been recognized as a useful method of determining whether hyperfunctioning tissues have been completely excised. However, an intraoperative QPTH assay may fail to detect the presence of double parathyroid adenomas. Use of this assay in conjunction with preoperative and intraoperative localization studies has led to the advocacy of more directed cervical procedures, such as limited, video-assisted, and endoscopic parathyroidectomy.

Biological Assay↗

Total endoscopic parathyroidectomy.

During the last five years, minimally invasive procedures have been adopted for the surgical treatment of hyperparathyroidism, because preoperative localization studies such as high-resolution ultrasonography and sestamibi scintigraphy, guidance by intraoperative scans, and the use of quick, intraoperative parathyroid hormone assay have improved. Endoscopic parathyroidectomy was performed by Gagner in 1996, and surgical procedures using endoscopy have been devised. The endoscopic procedures range from the "pure" endoscopic approach characterized by constant gas insufflation to video-assisted gasless techniques. We adopted the "pure" endoscopic approach, because a small incision can be made far from the neck and the cosmetic result is excellent. We report our technique with no scars in the neck region for endoscopic unilateral neck exploration with primary hyperparathyroidism and for endoscopic bilateral neck exploration with renal hyperparathyroidism.

Adult↗

Total endoscopic thyroidectomy: axillary or anterior chest approach.

We have developed endoscopic thyroidectomy by an anterior chest approach and an axillary approach. In this study, we evaluate the efficacy of these two types of endoscopic procedures and conventional open surgery. The degree of surgical invasiveness and the nature of patients' complaints after surgery were compared using the results of the operation and a questionnaire. The mean operating time for the endoscopic procedure was significantly longer than that for open surgery; however, there was no difference in postoperative pain in the three groups. Three months after surgery, the incidence of discomfort while swallowing in open surgery was higher than that in endoscopic surgery. All the patients who were treated using the axillary approach were satisfied with the cosmetic results. However, five patients (25%) who were treated using the anterior chest approach and 15 patients (75%; P < 0.01) who underwent open surgery complained abut the cosmetic results. The incidence of postoperative complaints after endoscopic surgery is significantly lower than that after open surgery. Patients who were treated using the axillary approach can obtain superior cosmetic results, compared with those who received other procedures.

Adult↗

Sentinel lymph node biopsy in patients with thyroid carcinoma.

The subject of performing prophylactic or elective modified dissections of the neck in patients with clinically occult lymph nodal metastases from thyroid cancers is controversial since metastases to lymph nodes are associated with high rates of recurrences. Biopsies of sentinel lymph nodes can be performed successfully in patients with thyroid cancers since they can be identified with dyes or 99mTc. Our preliminary findings indicate that biopsies of sentinel lymph nodes can be useful in the treatment of thyroid cancers; however, the clinical significance of identifying metastases in regional lymph nodes by this technique remains to be determined.

Adult↗

Laparoscopic partial adrenalectomy.

Since corticosteroids are indispensable hormones, partial or cortical-sparing adrenalectomies may be adopted for the surgical treatment of adrenal diseases. In this article, we describe the technique and results of these procedures. Laparoscopic partial or cortical-sparing adrenalectomy has been performed in 10 patients. Seven cases had an aldosterone-producing adenoma (APA) and three had a pheochromocytoma. Three cases with an APA and a case with a pheochromocytoma had tumors located far from the adrenal central vein, and the vein could be preserved. Four cases with an APA and two with a pheochromocytoma had tumors located close to the adrenal central vein, and it was necessary to section the central vein to resect them. All endoscopic procedures were performed successfully. There were no postoperative complications. At follow-up, adrenal 131I-adosterol scintigrams showed the preservation of remnant adrenal function in all patients. Laparoscopic partial or cortical-sparing adrenal surgery was safely performed, and adrenal function was preserved irrespective of whether the adrenal central vein could be preserved or not. We consider this to be a useful operative technique for selected cases.

Adrenal Gland Neoplasms↗

New operative strategies in primary hyperparathyroidism.

More than 95% of patients with primary hyperparathyroidism have been treated with bilateral neck exploration by experienced surgeons. This procedure has been performed without employing preoperative localization tests or specialized techniques of intraoperative measurement. A renewed interest in unilateral neck exploration for primary hyperparathyroidism emerged (in three developments), in an attempt to maintain the excellent cure rate and to minimize the invasiveness of the procedure. The first development was the introduction of sestamibi scintigrams as a new preoperative localization technique and intraoperative nuclear mapping with a hand-held gamma probe. The localization of adenomas using this technique was much more accurate than that of previous localization studies, allowing unilateral procedures to become feasible. Sestamibi guidance enables parathyroidectomies to be performed much more rapidly through a significantly less invasive dissection. Secondly, the intraoperative quick parathyroid hormone assay allows the confirmation of removal of the parathyroid mass. The third development was endoscopic parathyroidectomy. Various approaches have been shown to be technically feasible, including endoscopic procedures that rely on CO2 insufflation to create a working space or video-assisted procedures in which the working space is maintained through conventional external retraction. Given the safety and high success rate of the standard exploration, the potential advantages of these new strategies include decreased operating time, local or regional anaesthesia rather then general anaesthesia, and smaller incisions.

Humans↗

Oceanobacillus iheyensis gen. nov., sp. nov., a deep-sea extremely halotolerant and alkaliphilic species isolated from a depth of 1050 m on the Iheya Ridge.

An extremely halotolerant and alkaliphilic bacterium was isolated previously from deep-sea sediment collected at a depth of 1050 m on the Iheya Ridge. The strain, designated HTE831 (JCM 11309, DSM 14371), was Gram-positive, strictly aerobic, rod-shaped, motile by peritrichous flagella, and spore-forming. Strain HTE831 grew at salinities of 0-21% (w/v) NaCl at pH 7.5 and 0-18% at pH 9.5. The optimum concentration of NaCl for growth was 3% at both pH 7.5 and 9.5. The G+C content of its DNA was 35.8%. Low level (12-30%) of DNA-DNA relatedness between strain HTE831 and the species of these genera was found, indicating that HTE831 could not be classified as a member of a new species belonging to known genera. Based on phylogenetic analysis using 16S rDNA sequencing, chemotaxonomy, and the physiology of strain HTE831, it is proposed that this organism is a member of a new species in a new genus, for which the name Oceanobacillus iheyensis is proposed.

Base Composition↗

Operational tolerance induced by pretreatment with donor dendritic cells under blockade of CD40 pathway.

BACKGROUND: Dendritic cells can mount immune response as competent antigen presenting cells. Recently, it has been reported that immature dendritic cells induce prolongation of allograft survival. However, the ability of mature dendritic cells to induce operational tolerance is unclear. Therefore, in this study, we examined the ability of splenic mature dendritic cells to induce operational tolerance to fully allogeneic antigens using mouse heterotopic heart transplantation model. METHODS: CBA (H2k) mice received i.v. injections with donor splenic dendritic cells or B cells in the absence or presence of monoclonal antibody (mAb) specific for CD40 ligand or CD80/CD86 2 weeks before transplantation of a C57BL/10 (H2b) heart. RESULTS: When donor dendritic cells were injected i.v. 2 weeks before transplantation, rejection response was accelerated compared with that of naive mice [median survival time (MST) = 7 and 8 days, respectively]. However, when CD40 pathway was blocked by anti-CD40 ligand mAb, i.v. injection of donor dendritic cells but not B cells induced indefinite graft survival (MST >100 and 20 days, respectively). Mice treated with anti-CD40 ligand mAb alone rejected their grafts with a MST of 18 days. Intravenous injection of donor dendritic cells and B cells in combination with anti-CD80/CD86 mAbs was less effective to induce graft prolongation (MST = 9.5 and 13 days, respectively). CONCLUSIONS: Therefore, under blockade of CD40 pathway, mature dendritic cells were tolerogens in vivo independent of CD80/86 pathways.

Adoptive Transfer↗

Endoscopic total parathyroidectomy by the anterior chest approach for renal hyperparathyroidism.

BACKGROUND: During the past 3 years, minimally invasive procedures have been adopted for the surgical treatment of primary hyperparathyroidism, and we have tried to perform endoscopic total parathyroidectomy for renal hyperparathyroidism. METHODS: Five 5-mm trocars were inserted through the skin of the anterior chest under a general anesthesia. Carbon dioxide was then insufflated up to 4 mmHg, and the endoscopic surgery was performed. RESULTS: Endoscopic procedure was successfully performed in five patients. The mean duration of total parathyroidectomies was 236 min. No evidence of injury to the recurrent laryngeal nerve was observed in any cases. At follow-up, the serum calcium and parathyroid hormone levels had returned to within the normal range in all patients. Postoperative cosmetic status was excellent. CONCLUSION: We believe that endoscopic total parathyroidectomy by the anterior chest approach will find a role in the treatment of renal hyperparathyroidism.

Female↗

Endoscopic thyroidectomy and parathyroidectomy by the axillary approach. A preliminary report.

BACKGROUND: The use of endoscopic procedures leads to a reduction in the size of the surgical scar, making it more inconspicuous. In this paper, we evaluated the merits and limits of endoscopic neck surgery. METHODS: Between August 1999 and July 2000, 102 patients underwent neck surgery in our department for thyroid or parathyroid disease. Twenty-eight of them were treated by the axillary. A 12-mm and two 5-mm trocars were inserted through the skin of the axilla. Carbon dioxide was then insufflated up to 4 mmHg, and the endoscopic surgery was performed. RESULTS: Endoscopic procedures were performed successfully in 26 cases (19 thyroidectomies and seven parathyroidectomies). There were two conversions to open procedures. The mean operating times for the thyroidectomies and parathyroidectomies were 212 and 171 min, respectively. No evidence of injury to the recurrent laryngeal nerve was observed in any of the cases. The postoperative cosmetic status of the patients was excellent. CONCLUSION: We believe that endoscopic thyroidectomy and parathyroidectomy by the axillary approach will find a role in the treatment of endocrine diseases in the neck.

Adenocarcinoma, Follicular↗

Superficialization of hemodialysis access using a video-assisted procedure.

Brachiocephalic fistula is one of the main options to gain blood access for hemodialysis. Although the fistula is easy to establish, puncture becomes increasingly difficult because the cephalic vein runs deep and fibrous tissue is being continually deposited over the cephalic vein. Although superficialization-i.e., the removal of fibrous tissue along the basilic vein-has been performed with conventional surgery, the long incision along the cephalic vein induces the buildup of hard fibrous tissue so that puncture may remain difficult even after the operation. To avoid this problem, we tried superficialization of hemodialysis access using a video-assisted procedure and obtained a good result.

Arm↗

Endoscopic thyroidectomy by the axillary approach.

Neck surgery has recently become one of the newest fields for the application of endoscopic surgery because the resultant scar is small and inconspicuous. Still, some patients feel even a small scar on the neck is not cosmetically acceptable. We therefore have developed a new technique of endoscopic thyroidectomy by the axillary approach that leaves no scar on the neck at all. When this method is used, the small scar in the axilla is completely covered by the patient's arm in a natural manner. The cosmetic result is excellent, and sensory loss in the neck is negligible because the area of surgical dissection is small. We believe that endoscopic thyroid surgery by the axillary approach will find a role in the treatment of thyroid disease.

Axilla↗

Laparoscopic partial or cortical-sparing adrenalectomy by dividing the adrenal central vein.

BACKGROUND: We perform laparoscopic partial adrenalectomy without sectioning the adrenal central vein has been described because it is important to preserve this vein in the remnant adrenal gland in order to maintain its function. In this article, we describe our technique for laparoscopic partial or cortical-sparing adrenalectomy by dividing the adrenal central vein. METHODS: The procedures were performed in four patients with aldosterone-producing adenomas (APA) and two patients with pheochromocytomas. RESULTS: There were no postoperative complications. At follow-up, adrenal 131I-adosterol scintigrams showed that remnant adrenal function had been preserved in all cases. CONCLUSION: Since the vascular bed adjacent to the remnant adrenal gland is integral to the preservation of its function, it is important to perform procedures that do not separate the remnant adrenal gland from the retroperitonium space. Because the operative field is clearly visualized on the high-magnification video monitor, this delicate procedure can be performed with a high degree of accuracy via the laparoscopic approach. We consider this operative technique to be useful for selected cases.

Adrenal Cortex↗