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Biomedical subjects

N Tsubota

Publications and source records attributed to N Tsubota.

At least 73 records · Page 4Linked to original sources
PubMed1994

[Experimental study of an intratracheal stent made of shape memory alloy].

To develop a new prosthesis for treating tracheal stenosis and tracheobronchomalacia, we examined the usefulness of an intratracheal stent made of shape memory alloy (SMA), a titanium-nickel alloy composed of 50% of each metal. At its recovery temperature (37 degrees C), the SMA stent was designed to recall the memorized shape of a coil with a diameter of 5 or 6 mm and a length of 10 mm. For the present experiment, it was transformed to a smaller coil 3 mm in diameter at a low temperature (-50 degrees C) and then loaded into the prosthesis introducer tube. An experimental model of potentially fatal tracheomalacia was made surgically by cutting and fracturing the tracheal cartilages of rabbits and tracheal collapse was confirmed by rigid bronchoscope. The introducer tube with the SMA stent was inserted and then the prosthesis was advanced into the collapsed segment of the trachea using the stent pusher. The SMA stent warmed bo body temperature and recovered its memorized shape after 1-2 min. In 3 out of 8 rabbits, follow-up bronchoscopy performed at 6, 8, and 10 months after implantation revealed satisfactory patency of the SMA stent and the trachea. After follow-up, 3 animals were sacrificed for histological observation, which showed little proliferation of granulation tissue and no dislocation of the SMA stent from the malacic portion. The remaining 5 rabbits have been followed for 18-24 months and are doing well. We conclude that the SMA stent maintains good tracheal patency, causes little reaction in the tracheal wall, and is easy to handle. Thus, it shows the potential for clinical application.

Alloys↗
PubMed1994

[A case of the localized fibrous mesothelioma which size decreased temporarily].

A 46-year-old woman complained of a back pain and was pointed the abnormal shadow on chest X-ray by the physician, so she consulted our hospital in January 1987. After a few weeks, the size of the shadow decreased with no treatment, then we followed up her with roentgenograms. Since '91, its size had increased again. Needle biopsy did not give us the diagnosis, but we performed the operation because we suspected some malignant disease. We resected the tumor with the enough surgical margin. Its size was 4 x 3 x 3 cm, its surface was white and smooth. Its was elastic hard and had the pedicle which jointed the visceral pleura. Histological diagnosis was the localized fibrous mesothelioma.

Female↗
PubMed1994

[A case of intrathoracic meningocele associated with neurofibromatosis].

A rare case of intrathoracic meningocele associated with neurofibromatosis was reported. A 47-year-old female was admitted to our institute because of an abnormal shadow on chest X-ray. The chest X-ray film showed homogenous opacity with a well defined margin in the right apex. Chest CT showed an enlarged intervertebral foramen and defect of the vertebral arch around the tumor. There was no scoliosis. Though preoperative diagnosis was dumbbell type neurinoma, the tumor was found to be a protrusion of dura mater with spinal fluid out of the spinal canal, covered by thickening tumorous tissue. Part of the wall was excised and the residual opening was carefully repaired and wrapped by the pedicled parietal pleura. Retrospectively, MRI showed characteristic findings of intrathoracic meningocele. The tumorous part of it was diagnosed as neurofibroma on histological examination.

Female↗
PubMed1993

The unusual development of empyema with multiple alveolobronchiolar fistulae 8 years after non-curative resection and radiation for lung cancer: report of a case.

We present herein the case of a man who developed empyema with multiple lung fistulae 8 years after receiving postoperative radiation for a residual tumor on the bronchial stump. The patient was successfully managed with two-stage surgery, involving an open window thoracotomy, followed by omental flap transfer. This case documents how postoperative radiotherapy that was effective following non-curative resection was also responsible for the development of empyema. Furthermore, although the empyema was successfully treated using the omentum, a small free space remained in the thorax, which resolved within 2 months.

Aged↗
PubMed1993

Operative approaches for left-sided carinoplasty.

Carinoplasty was performed in 42 patients: 7 with wedge pneumonectomy, 15 with sleeve pneumonectomy, 14 with one-stoma-type carinal reconstruction, 5 with montage-type carinal reconstruction, and 1 other. Diagnoses in the 42 patients consisted of lung cancer in 31 (73.8%), tuberculous stenosis in 10 (23.8%), and tracheobronchial injury in 1 (2.4%). The thoracotomy was on the right side for lung cancer in 77.4% and on the left side for tuberculous stenosis in 80.0% (p < 0.01). Left-sided carinoplasty was performed in 14 patients using four approaches: midline thoracotomy in 1, left thoracotomy in 10, midline sternotomy and left thoracotomy in 2, and bilateral thoracotomies in 1. Left wedge or sleeve pneumonectomy, without right thoracotomy, could be done by midline sternotomy and left thoracotomy but with limited tracheal resection. Left one-stoma-type carinoplasty was undertaken, sacrificing one lobe, as an alternative to pneumonectomy, where an approach drawing the carina down to an aortopulmonary window was considered to be preferable to the drawing-up approach.

Anastomosis, Surgical↗
PubMed1993

Qualificated discrimination of ovarian malignancy by diagnostic ultrasound.

Ultrasonograms of 214 ovarian masses in 184 patients were studied to discriminate ovarian malignancies from benign masses and to help in developing a new scoring system using ultrasonographic findings with weight-adjusted scores. The 76 masses that showed cystic patterns only were directly determined to be benign, having an expected success rate of 97.4%. The remaining 138 masses, of which 116 showed mixed patterns and 22 of which showed solid patterns, were analyzed by the Quantification method No. 2 of Hayashi to select the effective ultrasonic findings and to obtain a good discriminant function. Eleven findings (items) expressing 29 categories were selected, and a discriminant function composed with a weight-adjusted score for each category was obtained as the result of the analysis. Using these functions, the 86.6% of the ovarian masses with mixed or solid patterns were correctly discriminated as being malignant, borderline-malignant, or benign. According to internal checks of all ovarian masses, the success rate was 90.2%. Then 73 ovarian masses of 65 new patients were discriminated as the external check, and a success rate of 93.2% was obtained. It is concluded that this newly developed scoring system using ultrasonic findings is useful in discriminating ovarian malignancies from benign ones.

Algorithms↗
PubMed1993

A huge non-invasive thymoma causing acute dyspnea.

We report a patient with an extra-ordinarily huge thymoma weighing 1,930 g and measuring 21 x 20 x 15 cm that filled almost the entire hemithorax. The tumor was successfully removed and the patient made a good recovery. Despite of its large size, the tumor was benign both clinically and histologically, and the pathological diagnosis was epithelial thymoma of non-invasive type. The perioperative changes of this patient's lung function are discussed in detail.

Acute Disease↗
PubMed1993

Results of surgical treatment for calcified tuberculous empyema: improved pulmonary function obtained with lung preserving policy.

We treated thirteen cases of calcified tuberculous empyema during the nine years from 1984 to 1992. Six patients having mild symptoms were categorized as Type I, and the remaining seven with severe symptoms as Type II. The patients of Type I were all successfully treated by complete empyemectomy with or without lung resection. All the patients of Type II suffered from major symptoms and were burdened by larger empyema cavities with formation of bronchial fistulas. Five of the latter were successfully treated, but two died, one from MRSA infection and another from intestinal necrosis following omentopexy. Our guide lines for the treatment of tuberculous empyema are: Lung resection must be minimal. Type I patients could be managed by simple empyemectomy with or without minor thoracoplasty. Open thoracostomy prior to the empyemectomy is not necessary. If the patient who belongs to Type II is aged and in a critical state, open thoracostomy must be taken as the first choice. Omentopexy is reliable, but it should be restricted to selected cases. Reasonable dead space and minor air leakage may safely be left behind if the cavity is surrounded by noninfected raw surface of the chest wall and diaphragm. Better quality of life was revealed by exercise test with improved oxygen consumption, compared to the preoperative state.

Aged↗
PubMed1993

[Projects in surgery for lung transplantation].

Lung transplantation was simulated in 9 essential items in the surgical side. The possibility to utilize cardiac death donor instead of cerebral death donor was discussed. The transplant window was shown in a patient with primary pulmonary hypertension. The informed consent must be authorized at the specific meeting. For the pre- and postoperative care, it is essential for surgeon to treat on the team which is consisted of members from the specific regions. With donation, a method of the standardization for graft preservation was shown by statistical analysis of many factors. The level of surgical techniques in Japan have been evaluated to be on the current level. In postoperative care, reimplantation response, infection, and rejection are important factors which have been clinically overcome in preceding institutions. However, a practical method of established diagnosis for acute rejection remain unresolved. In addition, CMV infection will be an unavoidable problem in Japan. The research of immune tolerance has been successfully underwent in experiments to overcome chronic rejection.

Humans↗
PubMed1992

A study on optimal temperature for isolated lung preservation.

Fifty-two heart-lung blocks (grafts) of New Zealand white rabbits were used for determining optimal temperature in lung preservation. Grafts were inflated with room air and preserved by simple surface cooling at arbitrarily determined temperatures for 18 hours. Graft function was assessed by nonrecirculated perfusion with autologous blood. Segmented regression models between functional parameters and preservation temperature (T) were applied for determining optimal temperature. Graft ability was also assessed from the point of view of pulmonary circulation by indocyanine green dilution rate of effluent and histological distribution of carbon particles. Significant segmented regression curves and lines between parameters of effluent oxygen tension (PO2) and wet-dry weight ratio (W/D), and T were obtained as follows: PO2 = 150/(1 + 3208.1[e-1.17T]), p less than 0.01; PO2 = -13.8T + 222.6, p less than 0.05; W/D = 5.0 + 1.5/(1 + 0.0028[e0.94T]), p less than 0.01; W/D = 0.075T + 4.52, p less than 0.05. Optimal temperature for lung preservation by topical cooling was calculated as 8 degrees to 9 degrees C from each intersecting point of regression equations. Analysis of regression curves suggested that the most common hypothermic ischemic injury during preservation by topical cooling is pulmonary vascular obstruction, which might be induced at temperatures lower than the critical temperature of 6 degrees to 7 degrees C. Indocyanine green dilution rate and histological findings supported the results of graft functional parameters.

Animals↗
PubMed1992

[A retrospective group study on post-thymectomy myasthenia gravis].

Retrospective group study on post-thymectomy myasthenia gravis (post-Tm MG) was carried out. Five hundred and twenty-seven resected thymoma cases (133 cases with MG and 394 cases without MG) were collected from 9 hospitals. Post-Tmx MG occurred in 18 out of 394 cases -4.6% of thymoma without MG-, and these 18 patients with post-Tmx MG were investigated retrospectively. As to surgical procedures, the mode of operation, either thymectomy or thymo-thymectomy was not thought to be an important factor in the pathogenesis of post-Tmx MG. These 18 patients could be divided into 7 with early onset and 11 with late onset. In the early onset group, post-Tmx MG occurred within 6 months after the operation, and these 7 patients may have had subclinical MG at the time of the initial operation. In the late onset group, post-Tmx MG was noted in 5 patients when recurrence of the tumor was confirmed, the latest being 11 years after operation. The pathogenesis of post-Tmx MG could not be clarified in the other 6 patients (33.3%). For further evaluation of these 6 cases, a prospective studies with large scale are needed.

Adolescent↗
PubMed1992

[A case of subglottic tracheal stenosis following tracheostomy successfully treated with laryngo-tracheal anastomosis].

A 77-year-old male patient underwent laryngo-tracheal anastomosis for subglottic tracheal stenosis. He developed exertional dyspnea 10 month after tracheostomy. Anterior and lateral wall of the cricoid cartilage and the first two tracheal cartilages were resected, preserving the recurrent laryngeal nerves. The distal trachea was anastomosed to the thyroid cartilage primarily and tracheostomy was made at 6th tracheal ring. Postoperatively, anterior flexion of the neck was maintained for a week. Oral intake was started on the 2nd postoperative day. The patient showed smooth recovery. The important points of this operation are: 1) preoperative evaluation of the residual subglottic space, 2) intraoperative care for preservation of the recurrent nerves, especially at the lateral sides of the crycoid cartilage, and 3) postoperative maintenance of the cervical anterior flexion.

Aged↗
PubMed1991

A case of empyema developing thirteen years after a pneumonectomy treated using pedicled omentum which was followed by intestinal obstruction.

Postpneumonectomy empyema is one of the most difficult complications for the thoracic surgeon to treat. We report herein a case of a 62 year old diabetic man who developed empyema 13 years after a pneumonectomy for cancer, which was successfully treated using an omental pedicle flap. Postoperatively, the chest would healed uneventfully, however, a bowel obstruction developed which was subsequently treated by removing the remnant omentum that had adhered to the bowel.

Colonic Diseases↗
PubMed1991

Efficient production of biologically active human prolactin in Escherichia coli.

To obtain an adequate amount of human prolactin (hPRL) for elucidation of the structure-function relationship, we have expressed the hPRL cDNA in Escherichia coli (E. coli) by using a high-expression vector. The vector contained a chimeric gene encoding a fusion of protein A, a peptide sensitive to collagenase digestion and hPRL, which was inserted downstream of the right direction promotor of lambda phage. The resulting protein fusion was purified through three column chromatographies of immunoglobulin G-linked Sepharose 4B, DEAE-5PW, and phenyl-5PW. In a typical experiment, a final sample with a purity of more than 80% was obtained with a recovery of more than 40% judged by enzyme-linked immunosorbent assay (ELISA). The fusion thus obtained was digested with collagenase, and protein reactive to anti-hPRL antibody was purified through phenyl-5PW column chromatography. The hPRL sample was found to be identical to authentic hPRL with respect to the amino acid composition and an N-terminal sequence of 20 residues, except that it contained an additional four amino acids at the N-terminal end. This peptide was presumed to be derived from the collagenase-target sequence. The hPRL thus obtained was found to be as active as the authentic hormone either immunologically judged by ELISA or biologically judged by the growth stimulatory effect on rat Nb2 lymphoma cells.

Amino Acid Sequence↗
PubMed1991

[Development of posture measuring apparatus using goniometer and inclinometer. 1. Description of the apparatus and its usefulness].

A new posture measuring apparatus was developed for time and motion study in the field of industrial health. This apparatus can record and classify working postures by measuring the angles of joints and trunk inclination. The angles of joints are measured by newly developed goniometers which use the bending loss of rubber optical fibers. The trunk inclination is measured by an inclinometer which uses photointerrupters. The measured angle data stored in the memory of this apparatus are transferred to the host computer and analyzed. Postures are classified automatically and subjectively according to discriminant functions which are calculated from the preliminarily measured data by discriminant analysis. Test measurement was carried out to classify four postures; standing, forward bending, half sitting and sitting. The goniometers were set on the right hip joint, knee joint, and ankle joint and the inclinometer was set on the right side of the trunk. The postures were changed in the order of standing, forward bending, half sitting, and sitting every 30 s. The angles were measured every second and a total of 120 sets of angles were measured. All data including data during posture changing were classified correctly by discriminant functions. The measurement during baggage lifting up and putting down was also carried out. Ten baggages (each 7 kg in weight) were lifted up from the floor onto a desk (75 cm in height), put down back to the floor, and again lifted on the desk. In 2 min, baggages were lifted up for a total of 20 times and put down for a total of 10 times.(ABSTRACT TRUNCATED AT 250 WORDS)

Discriminant Analysis↗
PubMed1991

[Small sized non-small cell lung cancer in advanced stage].

Eighteen cases of non-small cell, small sized advanced lung cancer, out of 362 operated cases for 6 years excluding 7 cases of small cell lung cancer, 60 of preoperative treated and 27 of inoperable cases, were discussed. A small sized tumor was defined as a tumor within 8,000 mm3 in its volume, calculated by multipling three lengths measured on the resected specimens. There were fourteen cases with stage 3 and 4 (A), and four cases with N1 disease (B). In group A, three cases of twelve with N2 diseases showed the tiny skipping lesion in the mediastinum with negative regional nodes. Remaining two had a lesion of dissemination and pulmonary metastasis. In group B, they showed unusual way of N1 spread, in which two of them with left upper lobectomy had metastatic lymph nodes on the non-bearing lobe, the lower lobe, and other two cases took regional lymph nodes metastasis without invasive growth of the main tumor. Predominant histologic type was adenocarcinoma, but the subtype and the differentiation of it were not specific. The level of CEA was low below 5 ng/dl in most of them except three cases, in which it suggested massive positive nodes and pulmonary metastasis. Seven patients died of the disease in two years. Remainders are alive, 4 with and 7 free from the tumor with the longest period of 3 years and a half. N2 diseases of small sized tumor were found in the cases with the volume of 3 cm3 and more at almost same ratio.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Spontaneous remission in pure red cell aplasia associated with thymoma.

A 57-year-old woman with thymoma-associated pure red cell aplasia (PRCA) manifested spontaneous recovery of erythropoiesis. Anemia recurred before the surgical removal of her thymoma, however, and the second anemic remission following surgery did not occur promptly. In this report, we describe a rare occurrence of spontaneous remission in PRCA.

Erythropoiesis↗