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Biomedical subjects

T Nakatsuka

Publications and source records attributed to T Nakatsuka.

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

Alteration in synaptic inputs through C-afferent fibers to substantia gelatinosa neurons of the rat spinal dorsal horn during postnatal development.

The change in synaptic inputs through primary afferent C- and A-fibers during postnatal development was examined in substantia gelatinosa neurons of a rat spinal cord slice with an attached L5 dorsal root by use of the blind whole-cell patch-clamp technique; the synaptic responses were compared between the slices obtained from immature (postnatal days 21-23) and mature (postnatal days 56-60) male rats. The mono- and/or polysynaptic afferent inputs were monitored by recording glutamatergic excitatory postsynaptic currents and potentials evoked by stimulating C- and A-fibers, the identification of which was based on the values of threshold stimulus intensity and of the conduction velocity of the fibers, determined by intracellular recordings from dorsal root ganglion neurons. Immature substantia gelatinosa neurons received synaptic inputs through Abeta-, Adelta- and C-afferents, with proportions of 51%, 46% and 36%, respectively. In mature substantia gelatinosa neurons, C- and Adelta-afferent inputs were increased in number (to 84% and 86%, respectively), while Abeta-inputs were decreased to 9%. In both immature and mature rats, repetitive stimulation of C-afferents did not elicit any slow responses, which are longer in duration than the monosynaptic excitatory postsynaptic currents, although C-fibers are known to contain not only excitatory amino acids, but also neuropeptides such as substance P, which is thought to be involved in the production of slow responses. These results indicate that both C- and Adelta-afferents innervating substantia gelatinosa neurons are reorganized following maturation, accompanied by a withdrawal or elimination of Abeta-fibers from the substantia gelatinosa, probably due to a competition among the fibers during development. In spite of the developmental increase in C-fiber inputs, mature as well as immature substantia gelatinosa neurons did not display any slow synaptic responses, which appear to be mediated by transmitters other than excitatory amino acids.

Action Potentials↗
PubMed2000

Intramuscular haemangioma of the anterior chest wall.

Intramuscular haemangiomas of the chest wall are rare. We present the case of a 33-year-old man with an intramuscular haemangioma of the left side of the anterior chest wall located in the left sixth intercostal space. We resected the tumour and surrounding tissue. Histopathological examination of the tumour demonstrated an intramuscular haemangioma of small-vessel type. The patient has been free of recurrence for 5 years after surgery.

Adult↗
PubMed2000

Microsurgical reconstruction for caustic injuries of the oral cavity and esophagus.

Ingestion of caustic material often produces profound and irreversible pathologic changes that require reconstructive surgery of the organs damaged. This report describes the authors' successful experience with microsurgical techniques that allowed adequate reconstruction in three patients with cicatricial contracture of the oral cavity and esophagus following ingestion of caustic substances. All patients had attempted suicide by ingesting liquid alkali. Patients #1 and #2 complained of limited mouth opening and impaired tongue movement due to oral scar contracture. Contracture release in the first patient resulted in a defect from the anterior border of the mandible to the retromolar region. The defect was resurfaced with a 6 x 12 cm free forearm flap. Release of the scar contracture in the second patient resulted in a long, narrow, tortuous defect that was difficult to cover, even with a forearm flap, and a jejunal segment was microsurgically transferred as a patch graft to reconstruct the defect. Patient #3 had dysphagia due to stricture of the cervical portion of the esophagus. The defect after resection of the cervical portion was reconstructed by free jejunal interposition. Appropriately selected free-flap transfer in each case provided a satisfactory restoration of function of the oropharyngeal and digestive passages.

Adult↗
PubMed2000

Correction of cleft lip nasal deformity in Orientals with a cantilevered iliac bone graft.

We describe our technique for correcting a nasal deformity associated with cleft lip in oriental people. Cantilevered iliac bone grafts are used to provide additional structural support and to achieve the desired nasal projection and profile. Augmentation of the nasal bridge creates the illusion of a narrower nose. This technique was used in 20 patients with severe nasal deformities. Clinically and radiographically it consistently produced good, long-lasting results.

Adolescent↗
PubMed2000

Large myxofibroma of the mandible treated with segmental mandibular resection and vascularized fibular graft.

This report summarizes a case of large myxofibroma of the mandible. On the basis of the clinical appearance, radiographic findings, and biopsy specimen, the lesion was diagnosed as a myxofibroma. Segmental mandibular resection and immediate reconstruction by vascularized fibular graft were performed. At the 18-month follow-up there was no evidence of recurrence of the tumor, and good functional and aesthetic results were maintained.

Adolescent↗
PubMed2000

Anterolateral thigh flap donor-site complications and morbidity.

The authors examined donor-site complications and morbidity in 37 patients after reconstruction with free or pedicled anterolateral thigh flaps. Intraoperative assessment included damage to the vastus lateralis muscle and whether the main pedicle of the rectus femoris muscle had been killed. Postoperative assessment of the donor site included wound healing, range of motion, muscle strength, gait, and sensation. Patients were surveyed with a questionnaire about fatigue in their activities of daily life and the appearance of the donor site. All 32 patients who underwent primary skin closure could perform activities of daily life normally, and most (87.5 percent) reported that donor-site appearance was satisfactory. However, the severity of donor-site dysfunction was related to the degree of damage to the vastus lateralis muscle, and most patients (87.5 percent) had some loss of sensation at the anterolateral aspect of the thigh. Because of adhesions between the meshed skin graft and the underlying fascia, range of motion at the hip and knee was limited in significantly more patients who had received split-thickness skin grafts (60 percent) than patients who had undergone primary skin closure (3.1 percent). Therefore, wider flaps or flaps harvested nearer the knee may increase donor-site morbidity. The authors concluded that the incidence of long-term morbidity with the anterolateral thigh flap is low, although it is increased when the flap includes the vastus lateralis muscle or is wider and requires additional skin grafting at the donor site.

Adult↗
PubMed2000

Postoperative complications and functional results after total glossectomy with microvascular reconstruction.

Microsurgical reconstruction after total glossectomy can greatly improve quality of life; however, postoperative functional results are often unstable, and the effectiveness of total glossectomy remains questionable. To determine the problems of reconstruction after total glossectomy with laryngeal preservation and to examine the functional results of swallowing and speech, 30 patients who had undergone total glossectomy and reconstruction with free flaps were reviewed for this study. The patients ranged in age from 20 to 73 years, and 23 of the 30 had undergone reconstruction with a rectus abdominis musculocutaneous flap. Wider and thicker flaps were designed and transferred and were sutured to suspend the larynx. To maintain physiologic swallowing function after surgery, the extent of laryngeal suspension and cricopharyngeal myotomy was limited. Of the 30 patients, 21 (70 percent) could be decannulated with laryngeal preservation; 20 of these 21 could tolerate a normal/soft/pureed diet, and 1 was limited to a fluid diet. Speech was intelligible in 16 of the 19 patients evaluated. In 9 of the 30 patients, laryngeal function could not be preserved. In four of these nine patients, additional resection combined with total glossectomy caused severe aspiration and recurrent pneumonia. Two patients with preoperative cerebral dysfunction were also poor candidates for laryngeal preservation. Additionally, the transferred flap's lack of bulk in the oral cavity and the advanced age (73 years) of one patient and the poor motivation of another may have contributed to postoperative aspiration. Aspiration occurred in one patient because of local recurrence of a tumor. The presence of preoperative cerebral dysfunction (p = 0.025), resection of the epiglottis (p = 0.005), and postoperative orocutaneous fistulas (p = 0.04) were significantly associated with the failure of laryngeal preservation. However, because of the difficulty of enrolling a sufficient number of patients in the study and the inherent limitations of retrospective studies, multivariate analysis in this study showed that no factors, such as patient age, flap volume, and the type of neck dissection, were significant predictors of laryngeal preservation. Although prospective studies are necessary, the function of individual patients must be assessed so that the study experiences discussed here can be applied to subsequent patients.

Adult↗
PubMed2000

Characterization of a vitamin B12 compound in the edible purple laver, Porphyra yezoensis.

The edible purple laver, Porphyra yezoensis, contained 51.49+/-1.51 microg of vitamin B12 compounds per 100 g dry weight of the laver (mean +/- SEM, n = 4). A vitamin B12 compound was purified from the lyophilized purple laver and partially characterized. The silica gel 60 TLC and reversed-phase HPLC patterns of the purified pink-colored compound were identical to those of authentic vitamin B12, but not to those of vitamin B12 analogues inactive for humans.

Biological Availability↗
PubMed1999

Versatility of the inferior epigastric artery as an interpositional vascular graft in living-related liver transplantation.

We have used the recipient inferior epigastric artery as an interpositional vascular graft in living-related liver transplantation cases with hepatic artery obstruction, enabling us to restore the arterial inflow sufficiently to the transplanted liver. The inferior epigastric artery is easy to access during abdominal surgery. Easy to harvest, it is anatomically constant and has a caliber equivalent to that of the hepatic artery. Donor site morbidity is negligible. There is no risk of rejection because of the autograft. There has been no report on the availability of the inferior epigastric artery for hepatic artery reconstruction. We consider this vessel as a good option for an arterial conduit in case of the inadequacy or thrombosis of the hepatic artery in living-related liver transplantation.

Adolescent↗
PubMed1999

Reorganization of the primary afferent termination in the rat spinal dorsal horn during post-natal development.

To study the reorganization of the primary afferent input in the spinal dorsal horn during post-natal development, synaptic responses evoked by large Abeta and fine Adelta afferents were recorded from substantia gelatinosa (SG) neurons in slices obtained from immature (post-natal days 21-23) and mature rats (post-natal days 56-60). Threshold stimulus intensities and conduction velocities (CVs) of Abeta and Adelta afferents were determined by intracellular recordings of the antidromic action potentials from dorsal root ganglion (DRG) neurons isolated from immature and mature rats. In immature rats, excitatory postsynaptic currents (EPSCs) were elicited by stimulation sufficient to activate Abeta afferents in the majority of SG neurons (64.9%, 24 of 37 neurons), while most EPSCs observed in mature rats were elicited by stimulation of Adelta afferents (62.5%, 25 of 40 neurons). These observations suggest that the primary afferents innervating SG neurons were reorganized following maturation; Abeta afferents were the predominant inputs to the SG neurons in the immature state, thereafter Adelta afferents were substituted for the Abeta afferents to convey sensory information to the SG neurons. This relatively slow reorganization of the sensory circuitry may correlate with slow maturation of the SG neurons and with a delay in the functional connections of C afferents to the SG neurons.

Animals↗
PubMed1999

Pseudovitamin B(12) is the predominant cobamide of an algal health food, spirulina tablets.

The vitamin B(12) concentration of an algal health food, spirulina (Spirulina sp.) tablets, was determined by both Lactobacillus leichmannii ATCC 7830 microbiological and intrinsic factor chemiluminescence methods. The values determined with the microbiological method were approximately 6-9-fold greater in the spirulina tablets than the values determined with the chemiluminescence method. Although most of the vitamin B(12) determined with the microbiological method was derived from various vitamin B(12) substitutive compounds and/or inactive vitamin B(12) analogues, the spirulina contained a small amount of vitamin B(12) active in the binding of the intrinsic factor. Two intrinsic factor active vitamin B(12) analogues (major and minor) were purified from the spirulina tablets and partially characterized. The major (83%) and minor (17%) analogues were identified as pseudovitamin B(12) and vitamin B(12), respectively, as judged from data of TLC, reversed-phase HPLC, (1)H NMR spectroscopy, ultraviolet-visible spectroscopy, and biological activity using L. leichmannii as a test organism and the binding of vitamin B(12) to the intrinsic factor.

Bacterial Proteins↗
PubMed1999

Rescue of liver grafts from hepatic artery occlusion in living-related liver transplantation.

BACKGROUND: Hepatic artery thrombosis after liver transplantation remains a significant cause of graft loss and death. Retransplantation is a difficult option after living-related liver transplantation in Japan. METHODS: Twenty-seven patients underwent living-related liver transplantation with left-sided liver grafts donated from their relatives. The hepatic artery was anastomosed end to end under a surgical microscope. Anticoagulant therapy was maintained for 2 weeks after operation. Routine post-transplant Doppler ultrasonography together with serum blood tests were performed twice a day during the first 2 weeks. RESULTS: Three patients developed hepatic artery occlusion, which was identified by routine Doppler ultrasonography before the serum transaminase values increased on days 7, 7 and 3 after surgery respectively. In two of the three patients, no apparent arterial thrombosis was recognized and vasospasm was therefore considered to be the cause of the occlusion. Arterial patency was restored by urgent revascularization with reanastomosis in all patients, but one patient with a functional graft died from a cerebral haemorrhage on day 47. CONCLUSION: Early diagnosis of hepatic artery occlusion by routine Doppler ultrasonography and revascularization of the graft is an indispensable strategy for preventing graft loss after living-related liver transplantation.

Adolescent↗
PubMed1999

Congenital cheek fistula: a report of three cases.

Three cases of the rare condition of congenital cheek fistulae are presented. These differ from preauricular fistulae in terms of their location and the direction in which the fistula is lying. Each cheek fistula seemed to be situated along the line of the junction between the mandibular and maxillary processes of the first branchial arch.

Cheek↗
PubMed1999

Elevation of a constructed auricle using the anteriorly based mastoid fascial flap.

Two-stage methods for reconstruction of congenital microtia have been widely utilised. To obtain a desirable auriculocephalic angle and provide a nutrient support to the constructed auricle, elevation of reconstructed ears using a costal cartilage graft, the anteriorly based mastoid fascial flap transfer and a skin graft was performed as the second operation for nine microtia patients. In this procedure, the mastoid fascial flap was used instead of the temporoparietal fascial flap. Following the elevation of the reconstructed ear the anteriorly based mastoid fascial flap was harvested. A carved costal cartilage was grafted at the posterior wall of the concha and covered with the mastoid fascial flap, followed by a full-thickness skin graft from the inguinal region. The skin grafts took well and the appropriate auriculocephalic angle was preserved in all cases. This method was easy to perform and did not leave any scar in the temporal hair-bearing area.

Adult↗
PubMed1999

Free adipofascial flap for scalp reconstruction: case report.

The authors describe a case in which a large defect of the scalp was present after tumor excision. It was covered with a free adipofascial flap and a split-thickness skin graft, with satisfactory results. Numerous similar cases of scalp defects reconstructed with other free flaps have been described. But since donor-site morbidity is minimized with free adipofascial flaps, they should be used more often for reconstruction of scalp defects.

Adipose Tissue↗