Search PubMed⌕ Search

Biomedical subjects

T Yotsuyanagi

Publications and source records attributed to T Yotsuyanagi.

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

Reconstruction of a three-dimensional structure using cartilage regenerated from the perichondrium of rabbits.

Human tissues such as those found in the ear, nose, eyelid, lip, and larynx have complicated and delicate three-dimensional structures, which are difficult to reconstruct and restore to normal function following damage by tumor, congenital disease, or trauma. We devised a new reconstructive technique for the lost tissues by using cartilage regenerated from the perichondrium. In 12 ears of 12 rabbits, the layer between the perichondrium and the cartilage was stripped off. The exposed cartilage was punched out in large amounts to resemble a flexible, honeycomb-like structure. Then, we sandwiched the rabbit ears with two thermoplastic plates, which maintained a structure of the anterior surface of the human ear for 8 weeks. Structural change was studied in all cases, and some parts of the remodeled tissue were studied pathologically. Out of 12 ears, 8 had a rigid structure with a shape like a human ear using regenerated cartilage from the perichondrium of rabbits, 2 were infected, and 2 had a decubitus ulcer on the conchal surface as a result of compression from the plate. This study suggests that the use of the cartilage regenerated from the perichondrium may lead to a successful treatment also in humans for a variety of three-dimensional structures that have been damaged.

Animals↗
PubMed1999

[Intraoperative electrophysiological monitoring for functional preservation of the cauda equina during lumbosacral surgery].

Adequate electrophysiological techniques to monitor function of the cauda equina have been proposed for surgery in patients with lumbosacral lipoma or myeloschisis. Motor fibers were identified by electrical stimulation in the operating field with bipolar rectangular impulses of 200 mu sec duration at 2 Hz under 5 mA and compound muscle action potentials (CMAPs) recorded from the leg and anal muscles. By recording CMAPs from the tibialis anterior, the biceps femoris, the gastrocnemius, and the external anal sphincter muscles, all of the roots from the fourth lumbar to the fourth sacral segment were continuously monitored. To spare recording channels, recordings were obtained from the right versus the left side. In our institute, 5 patients have undergone lumbosacral surgery while using this monitoring system, and the results indicated that there was no postoperative neurological exacerbation in any of the cases. According to a combination of the CMAPs produced by stimulation, the segment of the stimulated motor root could be identified electrophysiologically. Monitoring of somatosensory evoked potentials was not performed because this would have required too much time and would have prolonged surgery. However, some sensory fibers, which appeared to be posterior roots of the cauda equina on intraoperative inspection, could be identified indirectly with CMAPs recording because of current spreading from the stimulation to motor fibers.

Action Potentials↗
PubMed1999

Management of the hairline using a local flap in total reconstruction for microtia.

In cases of microtia with a low hairline, the manner in which hair is removed from the reconstructed auricle must be taken into consideration. This is one of the most common but difficult problems with reconstruction for microtia. The authors describe a new technique that uses a simple regional flap to resolve this problem. The hair-bearing skin in the estimated auricular region and its covering are removed using a local flap from the hairless mastoid region. This is done in the first stage of auricular reconstruction, the costal cartilage grafting is done in the second stage, and elevation of the auricle is done in the last stage. In 38 auricles of 36 patients who were treated from 1993 to 1995, eight auricles of eight patients were treated with this technique. In all cases, the hairless flap healed well, without vascular stasis or skin necrosis. In addition, no complications from using this technique occurred in the later stages of auricular reconstruction. With this technique, the skin of the flap provides a good texture and color match to the auricle. In addition, the skin of the flap has good elasticity for the cutaneous pocket for cartilage grafting. The harvested area of the flap can be hidden behind the reconstructed auricle. The authors initially wondered whether the marginal scar of the transposed flap's position in the auricle would be conspicuous. However, all of the scar became inconspicuous because it was positioned in the scaphoid fossa.

Adolescent↗
PubMed1998

Oral mucosal adhesive film containing local anesthetics: in vitro and clinical evaluation.

In vitro and in vivo studies were conducted to gauge the effectiveness of a novel oral mucosa adhesive, moderately water-soluble, pliant polymer artificial dentifrice (AD) film containing dibucaine (DC) for relief of pain due to oral erosion. The film was prepared from a hydroxypropyl cellulose-M (HPC-M) ethanol solution containing varying amounts of DC, as well as polyethylene glycol. In the in vitro experiments, the disintegration of HPC-M showed a lag time of about 50 min, a much lower rate than that of drug release, which more or less leveled off after 50 min. Twenty-five percent of the DC was released from the film (0.113 and 0.225 mg/cm2) after the initial 5 min, which then reached about 80% after 50 min, the time at which the polymer began to break up. In the in vivo study, the local anesthetic effect of the film was evaluated in 23 patients (10 males, 13 females) suffering from the adverse effects of chemotherapy. When applied to the wet surface of the mucosa, the AD film absorbed moisture and showed excellent adhesion. Pain relief in patients lasted 2.2 +/- 0.21 and 4.3 +/- 0.25 h at DC doses of 0.113 and 0.225 mg/cm2, respectively. These results suggest that the AD film may cover mucositis sites of oral mucosa long enough to allow DC release and bring relief from pain arising from chemotherapy and/or radiotherapy.

Adhesives↗
PubMed1998

A study of the concentration of orally administered sparfloxacin found in exudates from suture wounds beneath occlusive dressings.

The concentration of orally administered sparfloxacin (SPFX), an antimicrobial agent, in exudates from the suture wounds beneath occlusive dressings has been measured. Twenty-one patients who received oral therapy with 100 mg of SPFX prior to surgery and 200 mg/day of SPFX after surgery were studied. During the operations, the suture wounds were covered by occlusive film. 48h post-operation, wound exudates under the dressings were drawn and measured using high performance liquid chromatography. SPFX values were 0.801+/-0.340 microg/ml (mean+/-SD). The results suggest that wound exudates beneath the occlusive dressing have concentrations of SPFX high enough to prevent infection in most cases when administered orally.

Administration, Oral↗
PubMed1998

Non-traumatic rhabdomyolysis with gluteal ulcer.

The case is presented of a 34-year-old woman with rhabdomyolysis due to massive intake of nimetazepam, a benzodiazepine hypnotic. On admission, the patient had numerous blisters all over the body. One of the blisters in the gluteal region developed into a deep ulcer accompanied by muscle necrosis although it was not at a pressure point. The ulcer needed surgical intervention. Rhabdomyolysis is caused by the lysis and necrosis of muscle due to direct or indirect injury, high fever, ischaemia, hypoxia or enzyme defects. Release of myocyte components into the circulation then may induce major problems, especially acute renal failure associated with hypermyoglobinaemia. However, there have been few reports of cutaneous ulcer formation in non-traumatic rhabdomyolysis.

Adult↗
PubMed1998

An auricular paper model.

We have devised a paper model of the auricle that is simple to design and easily fabricated. An oval-shaped sheet of paper is folded so that the prominent and hollow parts center around a helical crus and concha. Most parts of the human auricle can be created by using this model. Studies of the model show that a large skin area is required for the helical crus. The model is considered to be useful in simulating total or partial auricular reconstruction. It also reveals new possibilities in reconstructive methods using tissues composed of cartilage and skin, which are flat and large. Furthermore, it is interesting that the formation of our paper model by forward rotation and folding is compatible with the process of auricle embryonic development.

Animals↗
PubMed1998

Nonsurgical correction of congenital auricular deformities in children older than early neonates.

It has been reported that nonsurgical correction of auricular deformities is not effective except in early neonates. We have succeeded in nonsurgical correction using thermoplastic splints for congenital auricular deformities on 50 ears of 45 patients without severe hypoplasia in children older than 1 year. Details of the types of ears we attempted to treat were 26 cryptotias, 5 lop ears, 5 Stahl's ears, 3 prominent ears, 3 shell ears, and 8 other miscellaneous conditions. The patients were between 1 and 14 years of age with an average age of 3.6 years. Our results were categorized as follows: excellent (the auricle was delicately corrected into a desirable form and satisfied the patient), improved (the auricle was corrected into a rough form that did not attain to a desirable shape and an irregular form still remained; however, its improvement satisfied the patient), recurrent (the auricle was initially corrected but the deformity recurred), not improved (the auricle was not corrected to the desired form and the result did not satisfy the patient), and gave up (the patient gave up before treatment could be completed). In our results, the average period of splint application was 2.1 months. In 27 of the 50 cases, the treated ears were excellent. Eleven ear cases showed improvement. Six cases showed recurrence. Three cases did not improve. Three patients gave up treatment. It is suggested that nonsurgical auricular correction is possible in almost all children, even if they are not early neonates, when corrections are made continuously and gradually.

Adolescent↗
PubMed1998

Reconstruction of defects involving the upper one-third of the auricle.

We describe here a reconstructive technique for the repair of defects involving the upper one-third of the auricle using a combination of several flaps. For a defect of the preauricular surface only, a chondrocutaneous flap from the concha and a postauricular subcutaneous pedicle flap were used. For a full-thickness defect, the reconstruction was made by using the chondrocutaneous flap, the postauricular subcutaneous pedicle flap, and a postauricular skin flap. The final skin defect was collected in the postauricular region and was directly sutured or covered by skin grafting. Seven patients were treated by this procedure. Although the tip of the postauricular skin flap fell into partial necrosis in one patient, all of the other flaps were well healed without vascular stasis. All of the reconstructed auricles had good three-dimensional forms with satisfactory color and texture to match. There was neither constriction of the ear nor deformation owing to scar contracture.

Aged↗
PubMed1998

Reconstruction of congenital stenosis of external auditory canal with a postauricular chondrocutaneous flap.

We describe here a new surgical technique for treatment of congenital stenosis of the external auditory canal using a postauricular chondrocutaneous flap. Our technique prevents recurring stenosis by cartilage support and provides a sufficient extension of the canal. The chondrocutaneous flap is safely elevated, easily reaches the canal, and has ample blood supply. It is beneficial for its self-cleaning function that the remnant canal, which contains cerumen glands, is used as part of the reconstructed canal. Six patients with congenital stenosis of the external auditory canal were treated by our procedure. In these patients, three patients were treated by a postauricular approach and the others were treated by an endaural approach. All patients had very satisfactory results.

Child↗
PubMed1998

Enhanced rectal absorption of amphotericin B lyophilized with glycyrrhizinate in rabbits.

The influence of bases and additives in the formulation for rectal absorption of amphotericin B (AMB) lyophilized with dipotassium glycyrrhizinate (GLYK) was investigated using rabbits in relation to an in vitro release test. The release of AMB from the fatty base of Witepsol or a medium chain triglyceride (MCT) was markedly faster than that from the hydrophilic base of macrogol. The addition of polyoxyethylene (2) lauryl ether (POE(2)LE) into the fatty bases led to a marked increase in the release rate, whereas POE(9)LE or sodium lauryl sulfate resulted in a significantly lower release rate. Animals received rectally each of seven AMB formulations of Witepsol H-15, macrogol, MCT with surfactants and aqueous solution. The absorption of the AMB lyophilized mixture with GLYK at a 1:9 molar ratio from a MCT base was significantly superior to that from macrogol. The addition of POE(2)LE into the MCT base resulted in a marked increase in bioavailability, showing the highest bioavailability of 4.9%. High serum levels of over 100 ng/ml of serum were maintained for 24 h following administration. The lowest bioavailability was 0.32% for the macrogol suppository. There was a good correlation between the release rate of AMB from the formulations and bioavailability. These results suggest that an AMB rectal formulation may provide a promising therapeutic alternative to infusion, taking into account the serum level of AMB exceeding the minimal inhibitory concentration of the infecting organism.

Absorption↗
PubMed1998

[Cationic liposomes in gene delivery].

Cationic liposomes have been extensively explored as gene delivery vector for several reasons. It is because disadvantages of viral vectors include risk of replication, possible immunogenicity, and the difficulty of obtaining a large quantity of viral vectors. Currently, a variety of cationic components for liposome formulations have been developed. The components are broadly divided into two classes based on the chemical structure of hydrophobic moieties: long aliphatic (saturated or unsaturated) hydrocarbons and cholesterol ring. A variety of hydrophilic moieties also include tertiary amines, ammonium salt and spermine. The role of liposomes is to condense DNA to form complexes with high affinity to cell surfaces where possible fusion or destabilization of the membrane and/or endocytosis are involved. However, at present, little structure-activity relationships are known. Some vectors are on clinical trials approved by NIH.

Cations↗
PubMed1997

Fluorometric determination of serum and urinary aluminium with 8-quinolinol by kinetic-differentiation-mode micellar chromatography.

A new fluorometric method has been developed for the determination of aluminium with 8-quinolinol by kinetic-differentiation-mode micellar chromatography. The proposed method enabled the determination of aluminium down to 1 microgram/l in human serum and urine without preliminary deproteinization. The most remarkable point of this method is that only aluminium ion selectively responds among metal ions. The complex formation of aluminium in serum with 8-quinolinol was completed within a few minutes at room temperature. The serum matrix and aluminium chelate were separated on a reversed-phase column with an eluent containing acetonitrile, sodium dodecylsulfate, and Triton X-100, and aluminium chelate was detected at Ex 370 nm, Em 504 nm. The values obtained by this method were in good agreement with those of Zeeman graphite-furnace atomic absorption spectrometry. The proposed method will provide a simple and rapid technique for the determination aluminium in medical fields.

Aluminum↗
PubMed1997

Is prolonged and excessive cooling of a scalded wound effective?

An experimental study was carried out using rats to evaluate the effectiveness of prolonged and excessive cooling on the burned wound just immediately after injury. The wound was produced by applying a lint immersed in boiled water at 99 degrees C. The wound produced by applying a lint for 3 s, and then immediately soaking with tap water for 1 min, resulted in little damage. However, the wound produced by applying a lint for 10 s, and immediately after an ice cube applied for 10 min, resulted in the most severe damage. The wound produced by applying a lint for 10 s, and no treatment applied thereafter, and the wound produced by applying a lint for 10 s and immediately after soaked with tap water for 1 min, resulted in moderate damage. From this experiment, it is suggested excessive and prolonged cooling of the burn wound, such as using an ice cube immediately after injury, is harmful in some instances.

Animals↗
PubMed1997

Application of alginate gel as a vehicle for liposomes. II. Erosion of alginate gel beads and the release of loaded liposomes.

The possibility of producing calcium-induced alginate gel beads as a vehicle for liposomes was explored. The maximal loading of egg phosphatidylcholine liposomes (ca. 26 nm in diameter) in a fully-cured bead (1.2 mm in radius, initial alginate concn. of 4%) was 2.9 x 10(-6) mol/bead or ca. 18%, and the size of the bead slightly increased with an increase in liposome loading. The liposomes were well maintained within both fully-cured and washed beads. The liposome release from the fully-cured bead was much slower than that from the corresponding washed bead in a pH 7.4 releasing medium. The greater the liposome loading, the faster the release of the vesicles. The liposome release was investigated in terms of liposome loading, swelling of the gel body, calcium discharge and gel erosion, using washed beads. The liposome loading did not affect the bead erosion or calcium discharge but did the initial swelling ratio and liposome release. The results suggest that the loaded liposomes are not uniformly distributed in the bead but are rather gradually concentrated to the center. Such an inhomogeneous distribution of liposomes is possibly due to the fact that the gelation occurred instantly on the surface of the droplets, and the resulting gel network or layer acts as semipermeable membrane for liposomes and forces the vesicles to move into deeper concentric sections as gelation proceeds to the interior. As the liposomes loading increases, the forced migration might be very limited because of concentrically decreasing extra room to accommodate the vesicles in the bead.

Alginates↗