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Biomedical subjects

Y Tai

Publications and source records attributed to Y Tai.

At least 37 records · Page 2Linked to original sources
PubMed2000

Plasma-treated lenowoven polyethylene ribbon for bone fixation at dentoalveolar osteotomy.

Plasma-treated lenowoven polyethylene ribbon was used for splinting between teeth around osteotomy lines in anterior segmental dentoalveolar osteotomy. This fixation was continued for 2 to 3 months, during which there was no damage or fall of the ribbon. In addition, the patients were able to eat their usual food, had much less pain in the teeth and oral mucosa, did not feel uncomfortable in the mouth, had no tooth damage or carious teeth, and had a good aesthetic appearance. In all eight jaws (five patients), accurate and strong bone fixation was achieved based on the planned occlusion. Patient complaints and pain were obviously less with this method than other methods. Polyethylene ribbon is quite useful for bone fixation in anterior segmental dentoalveolar osteotomy.

Adolescent↗
PubMed2000

Purification, identification and phosphorylation of annexin I from rat liver mitochondria.

Annexin was purified from rat liver mitochondria to an apparent homogeneity with a molecular weight of 35 kDa as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The purified mitochondrial annexin (AXmito) was identified as annexin I by an immunoblot analysis using anti-annexin I antibody. The inhibitory effect of AXmito I on porcine pancreatic phospholipase A2 activity was as potent as that of bovine lung annexin I. The presence of annexin I in mitochondria was confirmed by an electron-microscopic study. AXmito I was shown to be phosphorylated by intrinsic protein tyrosine kinases on its tyrosine residues. This annexin was also phosphorylated by protein kinase C.

Animals↗
PubMed2000

Absorption enhancement of a protein drug by nitric oxide donor: effect on nasal absorption of human granulocyte colony-stimulating factor.

The objective of this study was to evaluate the effect of a nitric oxide (NO) donor, S-nitroso-N-acetyl-DL-penicillamine (SNAP), on the nasal absorption of recombinant human granulocyte colony-stimulating factor (rhG-CSF) in rabbits and to evaluate the irritation (cytotoxicity) potential of the NO donor on the mucosal membrane using a cultured cell system (strain KB, human epidermoid carcinoma of the floor of the mouth). Significantly higher serum G-CSF concentration and increased total leukocyte count in the peripheral blood were observed after coadministration of rhG-CSF (100 microg/kg) with SNAP at various doses (0.3-3.3 mg/kg). The serum G-CSF concentration and the increased total leukocyte count were markedly decreased by the presence of the NO scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethyl-imidazole-1-oxyl 3-oxide sodium salt (carboxy-PTIO), in combination with rhG-CSF and SNAP. However, no significant inhibitory effect of glutathione (peroxynitrite scavenger) on the absorption-enhancing effect of SNAP was observed. These results suggest that carboxy-PTIO inhibits the absorption-enhancing effect of NO released from SNAP. We found that SNAP has a very low potential for cytotoxicity, as evaluated by the cell detachment assay, release of lactate dehydrogenase (LDH) from cultured cells and morphological observations of nasal tissue of rabbits. It is concluded that a NO donor such as SNAP is a promising absorption enhancer for nasal protein-drug delivery.

Administration, Intranasal↗
PubMed2000

Prognostic significance of cyclin E overexpression in laryngeal squamous cell carcinomas.

Cyclin E plays a pivotal role in the regulation of G1-S transition and relates to malignant transformation of cells. However, the clinical significance of cyclin E in patients with laryngeal squamous cell carcinoma (LSCC) remains unknown. We examined the expression of cyclin E in 102 patients with LSCC and analyzed its relation to clinicopathological parameters, cell proliferation, and clinical outcome. Cyclin E overexpression was observed in 54 cases (52.94%) of LSCC and was significantly correlated with the tumor site (P = 0.012), tumor size (P = 0.006), poor differentiation (P = 0.026), lymph node metastasis (P = 0.012), and advanced stage (P = 0.002). A positive correlation between the cyclin E expression and proliferative activity of tumor cells was found (r = 0.896; P < 0.0001). Kaplan-Meier analysis showed that shorter disease-free and overall survival was significantly associated with proliferating cell nuclear antigen (PCNA) overexpression and cyclin E overexpression. When PCNA and cyclin E are combined, the patients with both PCNA overexpression and cyclin E overexpression had the poorest prognoses when compared with the other cases. Additionally, in early stage (I-II) cases, cyclin E was also revealed to possess a significant prognostic role. By multivariate analysis, lymph node metastasis and cyclin E overexpression were independent prognostic factors for disease-free survival, and tumor size, lymph node metastasis, advanced stage, as well as cyclin E overexpression were independent prognostic factors for overall survival. These findings indicate that cyclin E overexpression is associated with unfavorable clinicopathological parameters and represents an independent marker for cell proliferation and prognosis of LSCC.

Adult↗
PubMed1999

Total esophagectomy versus proximal esophagectomy for esophageal cancer at the cervicothoracic junction.

To investigate the adequate extent of esophagectomy and lymphadenectomy for an esophageal cancer localized at the cervicothoracic junction, the mortality and morbidity rates, survival rates, and patterns of recurrence were retrospectively analyzed in two groups-14 patients who underwent total esophagectomy with or without laryngectomy and 15 patients who underwent proximal esophagectomy with or without laryngectomy-at Kurume University Hospital from 1981 to 1996. Proximal esophagectomy with or without laryngectomy resulted in a lower hospital mortality rate and better overall survival for patients who underwent curative esophagectomy compared with total esophagectomy with or without laryngectomy. Multivariate analysis indicated that the extent of esophagectomy (total esophagectomy versus proximal esophagectomy) was not a prognostic factor. The incidence of recurrence was not different between the two groups. Lymph node metastasis or recurrence from such esophageal cancers was localized to the neck and upper mediastinum. For an esophageal cancer localized at the cervicothoracic junction, therefore, proximal esophagectomy with or without laryngectomy and with cervical and upper mediastinal lymphadenectomy could be better indicated for preselected patients.

Aged↗
PubMed1999

A surgical method for treating anterior skull base injuries.

Skull base surgery was performed on 18 patients with anterior skull base injuries. The operative technique consisted of opening the operative field in the anterior skull base via a coronal incision and a frontal craniotomy, debridement of the anterior skull base including the injured dura mater, performing drainage from the anterior skull base to the nasal cavity by ethmoidectomy, and reconstructing the resulting dural and anterior skull base defect using bilateral temporal musculo-pericranial flaps and a bone graft. Seventeen of the 18 patients recovered without any complications, although epidural abscesses in the anterior skull base had been present in four patients at the time of the operation. Only one patient developed an epidural abscess in the anterior skull base after the operation. None of the patients developed any other complications including meningitis, recurrent liquorrhoea or cerebral herniation. Satisfactory aesthetic results were achieved in 16 of the 18 patients. In one patient, uneven deformity of the forehead, which was caused by the partial sequestration of the frontal bone due to postoperative infection, was observed. In another patient, a depressed deformity of the forehead, which was caused by the partial loss of the frontalis muscle following the use of the frontal musculo-pericranial flap instead of a temporal musculo-pericranial flap, was observed. Anterior skull base reconstruction using bilateral temporal musculo-pericranial flaps provides excellent results in terms of patient recovery and aesthetics.

Adolescent↗
PubMed1999

A Reconstruction Method Using Musculopericranial Flaps that Prevents Cerebrospinal Fluid Rhinorrhea and Intracranial Complications after Extended Anterior Skull Base Resection.

Anterior skull base defects after extended anterior skull base resection including unilateral orbit and the dura were reconstructed using the temporal musculopericranial (TMP) flaps or frontal musculopericranial (FMP) flap in 14 patients. Dural defect was reconstructed with the TMP or FMP flap by making it overlap on the remaining dura around the defects. These flaps were also used, in principle, for the separation of the nasal cavity. For bone defects on the anterior skull base, a bone graft was transplanted in the place between the flap for dural reconstruction and the flap for the separation of the nasal cavity. Bone grafting was nor performed in patients who had an extensive defect and for whom a free flap was used for the separation. After surgery, CSF rhinorrhea did not occur in the 14 patients. Twelve patients did not develop any postoperative complications. Two patients had epidural abscess, but with debridement and the drainage to the nasal cavity, they did not develop severe intracranial complications. We conclude that reconstruction using musculopericranial flaps is a reliable and versatile method with minimum invasion and the shortest operation hours. In particular, musculopericranial flap for dura reconstruction was highly efficacious for the prevention of CSF rhinorrhea.

Journal Article↗
PubMed1999

Evaluation with three-dimensional computed tomography after anterior skull base reconstruction using two musculopericranial flaps and a grafted bone.

Postoperative evaluation by three-dimensional (3D) computed tomography (CT) was performed in 15 patients who underwent anterior skull base reconstruction using two musculopericranial flaps and a grafted bone sandwiched between the two flaps. Especially in the case of large bone grafts (4 x 4 cm or more), the graft was positioned with the convex side facing upward into the cranial cavity to avoid creating an intracranial dead space. The extent of the absorption and changes in the contour of the grafted bone were evaluated. Imaging was done at a CT level of 150 using a Proceed 3-D CT scanner (Yokogawa Medical Co., Tokyo, Japan). Donor bone for grafting to the skull base was harvested the cranium in 10 patients and the ilium in 5 others. Patients ranged in age from 7 to 76 years (mean, 47); there were 10 men and 5 women. The grafted bone ranged in size from 1 x 2 cm to 5 x 8 cm (1 x 2 cm to about 4 x 3 cm: 10 patients; 4 x 4 to about 5 x 8 cm: 5 patients).No marked absorption of grafted bone was seen in these 15 patients, and no brain hernia occurred. In patients with large bone grafts (4 x 4 cm to about 5 x 8 cm), a graft that had been positioned with the convex side facing upward into cranial cavity at the time of transplant was subsequently observed to be transformed into a downward convex contour of normal skull base. Fostoperative infection did not occur because of the dead space nor were there any symptom of pressure on the brain because of the upward convexity of the grafted bone.The present reconstructive method is not only a minimum invasive but also a safe and reliable method for anterior skull base surgery.

Journal Article↗
PubMed1999

An ipsilateral superdrainaged transverse rectus abdominis myocutaneous flap for breast reconstruction.

A conventional single pedicled TRAM (transverse rectus abdominis myocutaneous) flap is a musculocutaneous flap widely used for breast reconstruction. However, complications such as partial flap necrosis, fat necrosis, and fatty induration may occur as a result of unstable blood flow circulation to the flap. One major factor is venous congestion in the flap. In an effort to obtain more stable TRAM flap blood circulation, we anastomosed the ipsilateral deep inferior epigastric vein of a pedicled TRAM flap to the thoracodorsal vein. This procedure provides superdrainage by means of enhanced venous perfusion. This flap with superdrainage augmentation is referred to as a superdrainaged TRAM flap (12 patients). Changes in cutaneous blood flow were also assessed by measurement of cutaneous blood flow in zone IV using a laser blood flow meter (8 patients). The patients who underwent breast reconstructive surgery using this technique showed no evidence of postoperative complications such as flap necrosis, fat necrosis, or fatty induration. Satisfactory results were obtained during breast reconstruction in patients who had previously undergone a radical mastectomy with resultant large areas of tissue defects. In addition, the two patient groups, 12 patients with superdrainaged TRAM flap and 20 patients with single pedicled TRAM flap, were compared to assess differences in complications. The incidence of partial flap necrosis, fat necrosis, and fatty induration was lower among patients with superdrainaged flap than those with single pedicled flap.

Abdominal Muscles↗
PubMed1999

Functional reconstruction of swallowing and articulation after total glossectomy without laryngectomy: money pouch-like reconstruction method using rectus abdominis myocutaneous flap.

When a total glossectomy is performed without a laryngectomy, the functional recovery of swallowing and articulation is extremely important in maintaining the patient's quality of life. The authors established a money pouch-like reconstruction method in which a round and raised tongue is rebuilt using a rectus abdominis myocutaneous flap. In this method, the skin island of the rectus abdominis myocutaneous flap is created about 20 percent larger than the defect in both width and length. The skin island is sutured to the defect such that the excess skin folds into the shape of a money pouch. This allows the tongue to be reconstructed with its tip and dorsum touching the hard palate and its base bulging in the dorsal and posterior directions. Misswallowing was not detected in the three patients who had this surgery, and each of them had improved articulation sufficient to carry out daily conversations.

Adult↗
PubMed1998

Cranioplasty with split lateral skull plate segments for reconstruction of skull defects.

This paper reports the use of cranioplasty using segments of split lateral skull plate to correct large skull defects (larger than 8 x 8 cm). The subjects consisted of 10 patients with head trauma who had undergone decompression surgery, and two patients who had undergone tumour resection. Bone grafts were obtained by cutting approximately 2 cm wide strips from the lateral skull plate using a bone saw that was inserted from a free margin of the bone defects. By cutting strips laterally from the bone defect, the necessary amount of split lateral skull plate can be obtained without performing craniotomy. The pieces of split lateral skull plate are then fixed to the defect using wire or titanium mini-plates. At this point, the selection of bone grafts that match the curvature of the dura mater is important, so that no dead spaces are created between the dura mater and the bone grafts. Infection was not detected in any of the 12 patients, and all bone grafts took completely. One of the 12 patients suffered from a pathological fracture and bone resorption 6 months after surgery. The fracture occurred because the use of basket-shaped reconstruction plates resulted in large spaces between the plate segments, and in addition the intracranial pressure was kept low by a V-P shunt, thus rendering the patient more vulnerable to atmospheric pressure.

Adolescent↗
PubMed1998

Reconstruction for palmar skin defects of the digits and hand using plantar dermal grafting.

The plantar skin is considered suitable for skin grafting onto the volar aspect of the digits and hand. However, this method is not widely used because it is associated with problems at the donor site. To solve these problems, a new method was developed in which two different layers of the plantar skin are harvested from the same site. In this method, a split-thickness skin graft of the upper layer including the corneal layer of epidermis and a dermal graft of the lower layer are harvested from the same plantar skin. The split-thickness skin graft is returned to the original donor site, whereas the dermal graft is used for the palmar skin defects on the digits and hand. To prevent drying, the dermal graft was covered with a wound-covering material to achieve good graft takes. Reconstruction was performed for 17 patients using this method, involving digit-only reconstruction in 8 patients, and wider reconstruction in the other 9. Excellent color and texture match of the graft and donor sites were obtained with no noticeable marginal scarring, and the durability of the skin was satisfactory. This method was useful for skin grafting to the digits and palms with minimal sacrifice to the donor site.

Adolescent↗
PubMed1998

A method that preserves circulation during preparation of the pectoralis major myocutaneous flap in head and neck reconstruction.

The present article describes a method that preserves circulation during the preparation of the pectoralis major myocutaneous flap used in head and neck reconstruction. The major disadvantage of this flap is its poor circulation and consequent partial necrosis. To solve this problem, we analyzed the circulation and hemodynamics of the pectoralis major myocutaneous flap (the perforator of the anterior intercostal branch located about 1 to 2 cm medial to the areola in the fourth intercostal space is important), evaluated the safe donor sites in the chest wall for a skin island (the perforator is included on the skin island's central axis), improved the surgical procedure for elevating flaps (for preventing perforator injuries), and devised a means to transfer flaps, thereby increasing the range of the flaps (the transfer route is under the clavicle). Using this technique, head and neck reconstruction was performed on 62 patients. The diagnosis included oral cancer (21), oropharyngeal carcinoma (10), parotid carcinoma (10), hypopharyngeal carcinoma (9), and other head and neck malignant tumors (12). Of these, partial or marginal necrosis of the flap caused by circulatory problems was detected in three patients (5 percent). Using our method, the problems associated with inadequate circulation in the pectoralis major myocutaneous flap were greatly alleviated, thus reconfirming the usefulness of this flap in head and neck reconstruction.

Adult↗
PubMed1997

Nipple-areola reconstruction with a dermal-fat flap and rolled auricular cartilage.

In reconstruction of the nipple-aerola complex, it is important to maintain nipple projection. The conventional methods of reconstructing the nipple using local skin flaps maintain the feature for a certain period postoperatively, but the height of the nipple eventually flattens as the scars soften over time. Considering that sustaining the feature of the nipple is most important for achieving and maintaining nipple projection, we have therefore devised a new operative technique. Rolled auricular cartilage is placed in the center of the bridge of the dermal base and is wrapped with bilobed dermal-fat flaps. This technique has the following advantages: The cartilage produces and sustains a good form of the feature without subcutaneous depression because the cartilage is supported by the bridge of the dermal base. Since the dermal base forms a bridge, the method is safe, maintains good circulation, and does not lead to any necrosis in the flap. This method also was compared with a method in which the rolled auricular cartilage is wrapped with a trilobed dermal fat flap.

Adult↗
PubMed1997

[Postoperative complications of anterior and middle skull base surgery].

The authors present the postoperative complications of skull base surgery based on a 10-year experience with 26 patients operated on via the supraorbital trans-basal or orbitozygomatic approach. The lesions included 19 malignant tumors and seven benign tumors. Postoperative cerebrospinal (CSF) leak occurred in one of the two patients in whom the dural defects were repaired with a fascia lata graft. None of the remaining 24 patients who were repaired with a musculopericranial flap suffered postoperative CSF leak. Three patients developed epidural abscess, but no infection was seen in the patients who had been reconstructed with a vascularized musculo-cutaneous flap to occlude the dead space. Preoperative radiation therapy correlated with a high incidence of postoperative infection. Cranial nerve deterioration or palsy occurred in four patients. Intraoperative injury of the internal carotid artery occurred in one patient who developed severe neurological deterioration. After an average follow-up period of 40 months (range 12 to 109 months), 68% of patients with malignant tumors and 100% of patients with benign tumors were alive with no evidence of recurrence.

Abscess↗
PubMed1995

Nucleus reticularis thalami connections with the mediodorsal thalamic nucleus: a light and electron microscopic study in the monkey.

Wheat germ agglutinin conjugated horseradish peroxidase (WGA-HRP) and biotinylated dextran amine (BDA) were used as tracers to study nucleus reticularis (NRT) connections with the mediodorsal nucleus (MD). Injections of WGA-HRP in the MD resulted in retrograde labeling of cells in the anteromedial segment of the NRT, the so-called rostral NRT pole. Injections of WGA-HRP and BDA in this NRT region resulted in dense anterograde labeling in the MD. Labeled NRT fibers gave off several collaterals to different MD regions ending with terminal plexuses of thin varicose fibers. In the neuropil, the varicosities were distributed at random, and no tendency to form pericellular baskets was noted. Postembedding immunocytochemistry for GABA was performed on the tissue containing anterograde WGA-HRP label for identification of NRT boutons under electron microscope. The double-labeled boutons were of small to medium size, contained a large number of pleomorphic vesicles, few mitochondria, and formed multiple symmetric synaptic contacts. The number of contacts established by one bouton ranged from 1 to 4 with an average of 1.8 per bouton. About 60% of these boutons made synapses on distal dendrites of GABAergic local circuit neurons; 33% of synaptic contacts were on distal dendrites of thalamocortical neurons, and the rest on their proximal dendrites and soma. NRT boutons were also found in serial synapses and triads. The results demonstrate that the NRT input to the MD is organized so that a single fiber innervates; different MD regions and its terminals form numerous synaptic contacts mostly on the distal dendrites of a large number of local circuit neurons and projection neurons.

Animals↗
PubMed1995

Involvement of annexin-I in glucose-induced insulin secretion in rat pancreatic islets.

Annexin-I was demonstrated to specifically present in islets and not in exocrine tissues of the rat pancreas and to have a diffuse and homogeneous distribution in all islet cells in our previous study. In the present report, to clarify the functions of annexin-I in rat pancreatic islets, especially in beta-cells, we investigated the role of annexin-I in insulin secretion. Immunoelectron microscopic analysis of pancreatic beta-cells demonstrated that immunogold particles reactive to annexin-I were almost exclusively observed on most of the insulin-containing granules (approximately 90%) and less frequently located in cytosol and other organelles, such as the endoplasmic reticulum and mitochondria. The number of annexin-I gold particles located on insulin granules after oral glucose administration was significantly increased compared with that observed in fasted rats. Moreover, when the isolated islets were stimulated by a high concentration of glucose (20 mM), the phosphorylation of annexin-I was markedly enhanced, and it was synchronized to insulin secretion. This phosphorylation mainly occurred on serine residues. H-7 (100 microM), a potent inhibitor of protein kinase-C, inhibited the phosphorylation to about 90%. These findings suggest that annexin-I might be involved in the regulatory mechanism of glucose-induced insulin secretion in rat pancreatic islets via phosphorylation-dephosphorylation processes.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗