Biomedical subjects

T Mawatari

Publications and source records attributed to T Mawatari.

At least 19 recordsLinked to original sources

PubMed2006

Effects of local infusion of OP-1 on particle-induced and NSAID-induced inhibition of bone ingrowth in vivo.

Excessive polyethylene wear particles from joint replacements may lead to periprosthetic osteolysis and loosening. Nonsteroidal anti-inflammatory drugs (NSAIDs) decrease fracture healing and bone ingrowth. We hypothesized that continuous local infusion of OP-1 (BMP-7) would increase local bone formation in the presence of two different adverse stimuli, polyethylene particles, and an oral NSAID. The Drug Test Chamber (DTC) was implanted in the proximal tibia of mature rabbits. The tissue growing into the chamber was exposed to OP-1 solution (110 ng/day), which was infused via an osmotic pump. Infusion of OP-1 alone for 6 weeks enhanced local bone formation in the chamber by 80% (p < 0.05) over infusion of carrier alone. In the presence of polyethylene particles, infusion of OP-1 increased local bone formation by 38% (p < 0.05) over treatment with particles and carrier. Oral administration of NSAID reduced local bone formation by 58% (p < 0.05); this suppressive effect caused by NSAIDS was completely reversed by the infusion of OP-1 (p < 0.05). These findings underline a potential role for local treatment with OP-1 to increase bone formation in the presence of potentially adverse stimuli such as polyethylene wear particles or NSAID use.

Alkaline Phosphatase↗

PubMed2005

[Lung cancer in patients with idiopathic interstitial pneumonia].

The purpose of this study was to determine the outcome of surgical treatment for lung cancer concomitant with idiopathic interstitial pneumonia (IIP). Between 1994 and 2003, 673 patients with primary lung cancer were treated. Forty-four patients (6.54%) of 673 patients were complicated with IIP. Their data were retrospectively reviewed. There were 37 male and 7 female with an average age of 67 years. They underwent 7 wedge resections of the lung, 3 segmentectomies, 32 lobectomies and 2 bi-lobectomies as surgical treatment for lung cancer. Five of these 44 patients died of acute exacerbation of IIP after the operation. The exacerbation occurred in an average postoperative day of 5 (range, 3 to 7) day. Preoperative values of serum CRP, LDH, SP-D and KL-6 failed to predict the occurrence of the exacerbation of IIP after the surgery. The preoperative value of %DLCO was lower in patients with the exacerbation than patients without the exacerbation (42.3+/-9.6% versus 66.8+/-18.8%, p=0.018). The postoperative 5-year survival rate for pathological stage I lung cancer were 84.9% and 70.2% (p=0.134) for patients without IIP and patients with IIP, respectively. Although the acute exacerbation of IIP after the surgery caused catastrophic outcomes, the long-term results in surgical treatment for stage I lung cancer simultaneously concomitant with IIP were not so poor. It is very important to avoid the postoperative exacerbation and further effort and research are required to avoid the exacerbation.

Aged↗

PubMed2004

The accuracy of image-guided knee replacement based on computed tomography.

Our study evaluated the accuracy of an image-guided total knee replacement system based on CT with regard to preparation of the femoral and tibial bone using nine limbs from five cadavers. The accuracy was assessed by direct measurement using an extramedullary alignment rod without radiographs. The mean angular errors of the femur and tibia, which represent angular gaps from the real mechanical axis in the coronal plane, were 0.3 degrees and 1.1 degrees, respectively. The CT-based system, provided almost perfect alignment of the femoral component with less than 1 degrees of error and excellent alignment with less than 3 degrees of error for the tibial component. Our results suggest that standardisation of knee replacement by the use of this system will lead to improved long-term survival of total knee arthroplasty.

Arthroplasty, Replacement, Knee↗

PubMed2004

[Strategy for surgical treatment for small peripheral carcinoma of the lung especially on systemic nodal dissection].

The diagnosis of small-sized (< or = 2 cm) non-small cell lung cancer (NSCLC) has increased with the development of computed tomography (CT), whereas unexpected extensive mediastinal involvement has been occasionally detected in such a small-sized lung cancer. We retrospectively analyzed the clinicopathological features to determinate the predictors for lymph node involvement in patients with a small-sized adenocarcinoma. One hundred and eighty one patients who underwent pulmonary resection and systematic nodal dissection for a peripheral small-sized adeno-carcinoma were reviewed. Of these, 24 patients (13.3%) had lymph node involvement. These patients were divided into 2 groups according to the existence of lymph node involvement, and the predictors for lymph node involvement were determined using univariate analysis and multivariate regression analysis. Univariate analysis revealed GGOR (ground glass opacity area/tumor area at the level of the greatest dimension of the lesion on chest computer tomography) > or = 25% (p = 0.0137) and pleural lavage fluid involvement (p = 0.0467) as predictors for lymph node involvement. No patients had lymph node involvement if their GGOR was higher than 50%. Multivariate regression analysis revealed GGOR > or = 25% (p = 0.0274), pleural tags on the lesion on chest CT (p = 0.0138) and pleural lavage fluid involvement (p = 0.0415) as predictors. We recommend performing systemic nodal dissection even if small peripheral adeno-carcinoma's maximal diameter is 20 mm or less. Systemic nodal dissection is unnecessary if the patients' GGOR > or = 50% or they do not have pleural tags or pleural lavage fluid involvement.

Aged↗

PubMed2004

[Removal of a steel bar after Nuss procedure for pectus excavatum; report of a case].

Recently, an increasing number of patients have been treated with the Nuss procedure for pectus excavatum. One of the merits is that this surgical procedure is less invasive and leads to good cosmetic results compared with the former traditional procedures such as sternal turn over. We have repaired 60 cases of pectus excavatum using the Nuss procedure at our institute since July 1999. We have experienced the removal of a steel bar, which was the first case of Nuss procedure at our institute.

Child↗

PubMed2003

[Surgery for metastatic lung tumors at our department during the last ten years].

We report on 86 cases (112 operations) who underwent surgery for metastatic lung tumors at our department during the last 10 years. The study subjects comprised 53 men and 33 women, and the average age was 51 (+/- 19) years. Of the 112 metastatectomies performed, 53 were conducted by video-assisted thoracic surgery (VATS), and 59 were performed via thoracotomy. The procedures employed for metastatectomy were lobectomy (22 cases), segmentectomy (4 cases), and partial resection. wedge resection (86 cases). The primary origin of the metastatic tumors was colorectal carcinoma in 22 cases, osteosarcoma in 13 cases, renal carcinoma in 10 cases, and breast carcinoma in 6 cases. The 5-year survival rates in subjects undergoing first and second resection for pulmonary metastases were 46% and 44%. Metastatectomy was performed 1, 2, 3, 4, 5, and 7 times in 73, 7, 1, 2, 2, 1 cases, respectively. The average number and maximum diameter of the metastatic pulmonary lesions at first metastatectomy were 1.9 and 27.6 mm. Metastatectomy is performed, as a rule, by VATS at our department, because the more highly invasive thoracotomy procedure influences the activity of the cancer cells in a suspended phase in an unfavorable manner. Furthermore, we believe that to the maximum extent possible, re-metastatectomy should also be performed by VATS. The survival rates at our institution have been satisfactory, and we attribute this to our following strict indications for metastatectomy. Re-metastatectomy should always be considered, as the survival rates are as favorable as those following the first metastatectomy.

Adult↗

PubMed2003

[Congenital tracheal stenosis due to complete cartilage rings with right pulmonary agenesis].

A 2-month-old male infant with severe dyspnea was diagnosed as having right pulmonary agenesis at birth and was admitted to our hospital after tracheal intubation with an endotracheal tube of 3 mm in diameter. However, the trachea was too stenotic to place the tube in the proper position. Chest X-ray on admission showed pneumonia of the left lung. Preoperative chest computed tomography (CT) scan and bronchoscopy showed that from the level of 12 mm beneath the coricoid cartilage, the trachea tapered and continuing to the tracheal carina and that the smallest tracheal level was located 18 mm distal from the coricoid cartilage, the area of which was 4 mm2. His respiratory condition rapidly deteriorated in spite of intravenous administration of antibiotics and mechanical ventilation. Percutaneous cardiopulmonary support (PCPS) was used to maintain his pulmonary function, and pericardial tracheoplasty was performed. Chest X-ray immediately after the operation did not show left lung reexpansion due to severe pulmonary edema. High-dose steroid pulse therapy was performed, but it was not effective. He died from acute respiratory failure due to infantile respiratory distress syndrome (IRDS) on postoperative day 3. The outcome in this case shows that it is very risky to repair tracheal stenosis in a patient with pneumonia using PCPS.

Cardiopulmonary Bypass↗

PubMed2003

[Complications of major lung resections by video-assisted thoracoscopic surgery].

Lobectomy by video-assisted thoracoscopic surgery (VATS) is gradually being performed more frequently because of advantages regarding pain and pulmonary function. Complications sometimes occur during or after VATS lobectomy. The purpose of this study was to analyze the incidence and the causes of the complications. From 1997 to 2003, 185 patients underwent VATS lobectomies. Selected diseases for this approach included primary lung cancer (n = 172), metastatic lung cancer (n = 7), benign lung tumors (n = 3) and lung sequestration (n = 3). The VATS approach was converted to open thoracotomy in 15 (8.1%) of 185 patients because of bleeding (n = 8), dense hilar adenopathy (DHA, n = 3), local extent of disease (n = 3) of intraoperative cardiac trouble (n = 1). Intraoperative complications involved injury to a blood vessel (n = 21), stapling failure (n = 15), lung injury (n = 7), nerve injury (n = 3), and others. Predictive factors for injury to pulmonary arteries was DHA (OR 37.0, p < 0.0001). Postoperative surgical death occurred in 2 patients due to pneumonia. Postoperative morbidity was 22.9%. A surgical operation without any good direct or thoracoscopic view or the use of a thoracoscopic tool without knowledge of the directions on its use should be avoided. The VATS approach should be replaced by open thoracotomy if there are DHA.

Humans↗

PubMed2001

Bronchial stump reinforcement in right pneumonectomy with fascia lata and gelatin resorcin formalin (GRF) glue: case report.

We reinforced the bronchial stump with fascia lata and Gelatin Resorcin Formalin (GRF) glue in a right pneumonectomy. This method was found to be simple and useful. We describe our case and the method herein. A 62-year-old woman had a malignant polypoid lesion which completely occluded the introitus of the right main bronchus and deviated to the introitus of the left main bronchus. Right pneumonectomy was done but materials (pleura, pericardium, intercostal muscle, etc.) obtained from the thoracic cavity were insufficient for bronchial stump reinforcement due to severe adhesion caused by prior tuberculosis. Therefore, we reinforced the bronchial stump using the fascia lata and GRF glue. Fascia lata is a superior material for reinforcement in terms of strength and ease of molding, as well as harvesting. GRF glue is a superior adhesive with rapid and strong fixation. We consider this method of reinforcing the bronchial stump with fascia lata and GRF glue to be feasible, in particular, for pneumonectomy or lobectomy without adequate material in the thoracic cavity because of severe adhesion or lesions.

Drug Combinations↗

PubMed2000

Posterior pulmonary lobe: segmental and vascular anatomy in human specimens.

The posterior pulmonary lobe (PPL) is defined by an aberrant fissure running horizontally on the costal surface of the lower lobe. We studied the frequency of the PPL, and the ramification of bronchi and vessels in the PPL, and so describe mainly these differences compared to the normal lung. Nineteen PPL cases (15 right and 4 left) were found in 273 (116 right and 157 left) human lung specimens. The incidence of PPL was 13% on the right side and 3% on the left side. The PPL frequently (right 87%, left 50%) corresponded to S(6) (superior segment). Analysis of the ramification of bronchi revealed that B(7) (medial basal bronchus) tended to form a common trunk with B* (subsuperior bronchus) or B(8) (anterior basal bronchus). Analysis of the ramification of veins revealed that V(6) (superior vein) tributaries were often double, and V(6) tended to disperse widely. Anomalies in which the segmental artery and vein communicated with other segments were found in seven cases (37%) (4 arteries and 3 veins, 6 right and 1 left) in PPL. These results show that the PPL does not always correspond to S(6) and frequently has an anomalous vessel from other segments. This is valuable surgical information, particularly in S(6) segmentectomy.

Bronchi↗

PubMed2000

Mixture of hyaluronic acid and phospholipid prevents adhesion formation on the injured flexor tendon in rabbits.

Dipalmitoyl phosphatidylcholine, a highly surface-active polar lipid, has been implicated as a potential boundary lubricant for synovial joints. We examined the effects of dipalmitoyl phosphatidylcholine on the flexor tendon and its protective effect against postoperative adhesion in two experimental steps. First, the flexor digitorum fibularis and the distal pulley of rabbits were set for a friction test. The test was performed with saline solution, sodium hyaluronate, or a mixture of dipalmitoyl phosphatidylcholine and sodium hyaluronate as the lubricant. The friction coefficient was significantly lower with the mixture of dipalmitoyl phosphatidylcholine and sodium hyaluronate than with saline solution or sodium hyaluronate. We concluded that the decreased friction coefficient indicates that dipalmitoyl phosphatidylcholine could complement the boundary-lubricating ability of the tendon. In the second experiment, we used an experimental adhesion model of the flexor digitorum fibularis in the rabbit. During the operation, either saline solution, sodium hyaluronate, or a mixture of dipalmitoyl phosphatidylcholine and sodium hyaluronate was injected into the tendon sheath. The specimen was sent to another tester, and the work required to tear off the adhesion was measured. The work required was significantly greater for the tendons that had been injected with saline solution than for those given injections of dipalmitoyl phosphatidylcholine and sodium hyaluronate. Our findings suggest that dipalmitoyl phosphatidylcholine plays an important role in the boundary lubrication of the tendon and that after tendon injury, the administration of a mixture of dipalmitoyl phosphatidylcholine and sodium hyaluronate may improve tendon lubrication and prevent adhesion formation.

1,2-Dipalmitoylphosphatidylcholine↗

PubMed2000

Successful surgical treatment of giant coronary artery aneurysm with fistula.

Giant coronary artery aneurysm with fistula formation is a rare entity. We report a giant coronary artery aneurysm with a maximum diameter of 70 mm with fistula, in which a favorable course was obtained after surgical treatment. We also review the literature on giant coronary artery aneurysms exceeding 50 mm in maximum diameter.

Blood Vessel Prosthesis Implantation↗

PubMed2000

Oxidative refolding of lysozyme assisted by negatively charged liposomes: relationship with lysozyme-mediated fusion of liposomes.

Oxidative refolding of denatured/reduced lysozyme was examined in the presence of charged liposomes composed of neutral 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and negatively charged 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG). Surface charge density of liposomes had a marked effect on the interaction between liposomes and reduced lysozyme which is observed in the early stage of the refolding. It was found that there was a critical level of surface charge density of liposomes (-0.15 C/nm2) at which the interaction between liposomes and lysozyme drastically changed. At the surface charge density of liposomes ranging from -0.15 to -1.4 C/nm2, the interaction between liposomes and lysozyme resulted in aggregate formation. In contrast, at the surface charge density ranging from 0 to -0.15 C/nm2, no aggregate formation was observed if the lysozyme/liposome molar ratio was less than 600. On the basis of the experimental results, a model for the interaction between charged liposomes and lysozyme was proposed, focusing on the mechanism of protein-induced fusion of charged liposomes as well as protein refolding on liposomes. Then, the optimal condition for oxidative refolding of lysozyme was examined in the presence of charged liposomes by controlling the lysozyme-liposome interaction. The reactivation yield of lysozyme was improved up to 85% in the presence of liposomes with a surface charge density of -0.14 C/nm2.

Journal Article↗

PubMed2000

Effect of vitamin K2 on three-dimensional trabecular microarchitecture in ovariectomized rats.

Menatetrenone, a vitamin K2 with four isoprene units, has been reported to improve osteoporotic bone loss. The purpose of this investigation was to clarify the effect of menatetrenone on the three-dimensional (3D) trabecular microarchitecture in ovariectomized (OVX) rats by using microcomputed tomography (MCT). Forty-two 13-week-old female rats were used and divided into four groups: the OVX (OVX + MK-4) group treated with menatetrenone, the (OVX untreated) group, the sham-operated (Sham + MK-4) group treated with menatetrenone, and the sham-operated group not treated with menatetrenone (Sham untreated) group. OVX rats were fed a calcium-deficient diet. Menatetrenone treatment was begun just after the ovariectomy, and the mean menatetrenone oral intake over the 8-week period was adjusted to 30 mg/kg BW per day. The proximal metaphyseal region of the right tibia was evaluated by dual X-ray absorptiometry (DXA) and MCT. A parametric analysis of the reconstructed trabecular volume was carried out using bone volume fractions, the fractal dimension calculated by the 3D box-counting method, and the connectivity density as determined by topological analysis. Menatetrenone significantly increased the trabecular bone volume, fractal dimension, and connectivity in the OVX + MK-4 group compared with the OVX-untreated group (p < 0.01). Our results suggest that an 8-week administration of menatetrenone protects against the loss of trabecular bone volume and its connectivity when treatment is begun just after the ovariectomy. Despite this apparent protection, it remains unknown whether it is possible to reestablish trabecular connectivity if therapeutic intervention occurs after the trabecular connectivity has been lost.

Alkaline Phosphatase↗

PubMed1999

Quantitative analysis of three-dimensional complexity and connectivity changes in trabecular microarchitecture in relation to aging, menopause, and inflammation.

There are several types of bone loss besides that associated with normal aging, eg, that associated with the menopause, and that associated with chronic inflammation, and these are considered to be caused by different mechanisms. The microarchitecture that results from these different bone-loss mechanisms would not be the same. The purpose of this study was to investigate differences in the three-dimensional trabecular microarchitecture in various types of osteopenia, using microcomputed tomography (Micro-CT). Thirty-five Fisher 344 rats were divided into five groups (control, young, senile, ovariectomized [OVX], and inflammation-mediated osteopenia [IMO]) and distal femoral metaphysis was scanned by Micro-CT to nondestructively acquire a 3-D CT stack consisting of 50 consecutive slices at a spatial resolution of 26 microm. The volume of interest, consisting of the secondary spongiosa, was prepared to analyze the 3-D trabecular microarchitecture. A parametric analysis was carried out using bone volume fractions, fractal dimensions, and the first Betti number in order to quantitatively express the mass, complexity, and connectivity of the trabecular microarchitecture. Complexity tended to decrease with age, and decreased significantly in estrogen deficiency-induced and inflammation-mediated osteopenia. Connectivity did not appear to change with aging, but was significantly decreased in estrogen deficiency-induced and inflammation-mediated osteopenia. There was no significant difference between the OVX and the IMO groups.

Age Factors↗

PubMed1999

A new friction tester of the flexor tendon.

We have developed a new device to measure the friction force and calculate the friction coefficient between a rabbit flexor tendon, a pulley and a proximal phalanx. The flexor digitorum fibularis tendon of a rabbit was taken intact with the proximal phalanx, and tendon pulleys were attached to both ends of the bone. Both ends of the tendon were clamped to acrylic plates and connected to stainless-steel plates equipped with strain gauges. A pretension of 1.96 N was applied so as not to loosen the tendon. The proximal phalanx was fixed to an acrylic plate on the actuator, which gave 8 mm of transfer to the acrylic plate at a speed of 2 mm/s. The interface between the tendon and the surrounded tissue created the friction force, when the load was applied on the distal pulley. The friction force could be obtained from the difference between the tension of both ends of the tendon, which was measured with strain gauges and sampled with a personal computer. The friction force and the friction coefficient were calculated from the measured force and the applied load. The load and the pre-loading time, which was defined as loading duration before gliding, were varied in order to observe the change of the friction coefficient. The friction coefficient was not affected by the load and increased with the pre-loading time. The value of mu(s) ranged from 0.027 to 0.111 (0.072 +/- 0.023), and that of (mu)d ranged from 0.010 to 0.069 (0.039 +/- 0.014) (pre-loading time was 5 s). Our method will allow for the examination of various surgical treatments and lubricants. Moreover, it can be applied to other tissues of any animals with similar structures to the rabbit's digitorum.

Animals↗

PubMed1999

Does the Adamkiewicz artery originate from the larger segmental arteries?

OBJECTIVE: The Adamkiewicz artery supplies most of the blood to the anterior spinal artery, which perfuses the anterior two thirds of the spinal cord. During operations for thoracoabdominal aortic aneurysm, detailed anatomic knowledge of the Adamkiewicz artery and its correlation with the intercostal and/or lumbar arteries is important to prevent postoperative paraplegia. METHODS: Minute dissection was performed on 102 formol-fixed adult cadavers without any history of circulatory disorders. The Adamkiewicz artery was found in the epidural space after laminectomy of the vertebrae. The entire course between the Adamkiewicz artery and the intercostal and/or lumbar artery was dissected carefully. The vertebral level, laterality, and mean diameter of all Adamkiewicz arteries were investigated. The correlation between the diameter of the Adamkiewicz artery and that of the intercostal and/or lumbar arteries was also determined. RESULTS: The mean number of Adamkiewicz arteries per cadaver was 1.3 +/- 0.65, and the mean diameter was 0.77 +/- 0.24 mm (range, 0.50 to 1.49 mm). Approximately 70% of the Adamkiewicz arteries originated from the intercostal and/or lumbar arteries on the left side, frequently at the T8-L1 vertebral level. There was no statistically significant correlation between the diameter of the Adamkiewicz artery and that of intercostal and/or lumbar arteries. CONCLUSION: This study provides evidence that, during operations on the thoracoabdominal aorta, the intercostal and/or lumbar arteries should be preserved, regardless of their diameter, to prevent postoperative paraplegia.

Adult↗

PubMed1999

A new, all-inside technique for meniscus repair.

A new method for arthroscopic meniscal repair using sutures with multiple knots was developed, and its mechanical strength was evaluated. Sutures are passed arthroscopically through the torn meniscus using a needle with a cleft in its tip, and when the needle is withdrawn, knots are placed both in the meniscus and the joint capsule. Our method does not require additional skin incisions and can be performed for repair of posterior tears. Furthermore, this all-inside technique minimizes the risk of popliteal neurovascular injury. Biomechanical analysis using bovine menisci showed that the maximum frictional force between the suture and meniscus was greater than the maximum strength of a suture itself. Our method is simple and rapid, making it easy to insert multiple sutures to achieve adequate stability.

Animals↗