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Biomedical subjects

S Tamai

Publications and source records attributed to S Tamai.

At least 199 records · Page 11Linked to original sources
PubMed1994

Biomaterials lubricated for minimum frictional resistance.

To improve the frictional characteristics of a biomaterial, the mechanical performance of a lubricated surface was studied. In vitro friction tests showed that the coefficient of dynamic friction of the lubricated surface was about 0.01 against rabbit bladder and the coefficient of static friction increased with the preload period. The efficacy of a lubricated cystoscope was evaluated by an in vivo test simulating cystoscope operation. The maximal and the total resistance force on the cystoscope model were found to decrease with the surface lubrication. Histological study revealed that urethral damage caused by rubbing with the cystoscope model was reduced by this lubrication technique. Presumably, prolonged retention of water on the lubricated surface region prevented tissue adhesion to the foreign material.

Animals↗
PubMed1994

Venous flap--its classification and clinical applications.

We previously reported pedicled venous flap survival using the rat model, as well as venovenous, arteriovenous, and arterialized flow-through venous flap survival using the rabbit ear model. For this study, we utilized these flaps clinically. Five of seven pedicled venous flaps survived, displaying superficial necrosis. The others became partially necrotic; they were transferred after dissection of a long pedicle vein. Eight of nine venovenous flow-through venous flaps survived; six displayed superficial necrosis. The nonsurviving flap became completely necrotic, possibly because only one donor vein and one recipient vein were used. Six of 10 arteriovenous flow-through venous flaps survived. The remaining four became partially necrotic, possibly because only one vein was anastomosed for outflow. The arterialized flow-through venous flap survived. The pedicled venous and venovenous groups studied seem likely to survive despite superficial necrosis. However, the draining vein should not be dissected more than 5 cm, and many draining veins should be anastomosed with recipient vessels.

Adult↗
PubMed1994

Present status of replantation in Japan.

We conducted a survey among 94 members of the Japanese Society of Reconstructive Microsurgery on the present status of replantation in Japan. The results indicate that 9,664 extremities were replanted (157 upper arms, 415 forearms, 471 hands, 8,320 digits, 33 thighs, 103 calves, 37 feet, and 128 toes); 8,227 replants survived, for a success rate of 85%. The survival rate was over 90% in 23 hospitals, and 7 of these hospitals replanted more than 100 limbs. Postoperative treatment consisted of continuous intravenous infusion of urokinase (120,000-240,000 U/day), heparin (10,000-20,000 U/day), and prostaglandin E1 (80-120 micrograms/day) for 3-10 days. Fifty-six surgeons attempted replantation whenever the patient requested it. At Nara Medical University, continuous local intra-arterial infusion of anticoagulants and fibrinolytic agents has increased the survival rate of the replantation to 97%, compared with 88% when using intravenous infusion.

Alprostadil↗
PubMed1994

Preservation of the vasodilative effect of endothelium-derived relaxing factor in the hind limb of the rat.

Using an extracorporeal circulatory system of fresh blood, the vasodilative effect of endothelium-derived relaxing factor (EDRF) secreted from vascular endothelium, stimulated by acetylcholine (ACh), was evaluated. The bioassay cascade technique was applied to elucidate the release of EDRF. Elevated blood pressure of freshly amputated rat hind limbs, created by injection of norepinephrine (NE), decreased by 56% with ACh infusion, suggesting the existence of EDRF in the peripheral vascular system of rat hind limbs. The vasodilative effect of EDRF could be preserved for at least 6 hours when stored at room temperature. The effect of EDRF decreased markedly following storage for more than 9 hours at room temperature and storage for more than 3 hours at 4 degrees C.

Acetylcholine↗
PubMed1994

Electron microscopic evidence of a viral nature for osteoclast inclusions in Paget's disease of bone.

Circumstantial evidence from electron microscopic and immunological studies support the view that Paget's disease of bone represents a slow virus infection. However, there is only limited information available regarding its electron microscopic, enzyme and immunocytochemical characteristics. Two cases were studied using electron microscopy with particular emphasis on the inclusions in osteoclasts. Detailed ultrastructural and cytochemical studies including immuno-electron microscopy were performed. Some osteoclasts demonstrated specific virus-like structures composed of aggregations of microtubules in the nucleus and cytoplasm. The structures were easily digested by trypsin or protease, and were sensitive to RNase, which provided substantial evidence of a proteinaceous nature and inclusion of ribonucleic acid. Immunocytochemical examination identified binding of anti-respiratory syncytial virus and anti-measles virus antibodies in the tissue obtained from one of the two cases examined. The presence of viral antigens in structures in the cytoplasm of Pagetic osteoclasts supports the theory of paramyxovirus involvement in this disease.

Antigens, Viral↗
PubMed1994

Massive intestinal bleeding caused by an ileal arteriovenous malformation: report of a case.

We report herein the case of a 43-year-old man in whom gastrointestinal bleeding was found to be caused by a large arteriovenous malformation (AVM) in the ileum. Emergency angiography proved invaluable in disclosing the AVM as the bleeding source, after which the patient was successfully treated by surgery. Although the number of reports of AVM has recently been increasing, ileal AVMs are still relatively rare. Moreover, according to the Japanese literature, no other patient has had such marked and large feeding arteries and draining veins as those in the patient described in this report.

Adult↗
PubMed1994

Portal vein aneurysm in the liver associated with multiple vascular malformations.

Portal vein aneurysm (PVA) includes focal dilatation of the portal vein, and was formerly thought to be a rare disease. We report a 46-year-old man with chronic aggressive hepatitis and intrahepatic portal vein aneurysm communicating with the hepatic vein. Hemangiomas in the liver and intracranial arteriovenous malformation (AVM) were also found. To our knowledge, this is the first report of a case of PVA in a patient with congenital intracranial AVM. As the PVA in this patient communicated with the hepatic vein, and as hemangiomas in the liver and intracranial AVM were also present, the pathogenesis in this patient seems to have been congenital anomaly of the vasculature.

Aneurysm↗
PubMed1994

Ultrastructural cytochemical demonstration of proteoglycans and calcium in the extracellular matrix of chondroblastomas.

To clarify the characteristics of the extracellular matrix of chondroblastomas, six cases were studied under the electron microscope, with special reference to proteoglycans and calcium in the cellular areas. In ruthenium hexammine trichloride (RHT)-stained sections the matrix was observed to be composed of rounded or polygonal fine granules and unbanded thin filaments that appeared to link neighboring granules together. Treatment with potassium-pyroantimonate showed intracellular accumulation of precipitates, mainly localized within the cisternae of the rough endoplasmic reticulum as well as in the extracellular matrix. The presence of calcium in the precipitates was confirmed using x-ray energy dispersive analysis. These findings, similar to characteristic features observed in calcifying systems, support the theory that chondroblastomas are of chondrogenic origin.

Calcium↗
PubMed1994

Proximal lateral leg flap transfer utilizing major nutrient vessels to the soleus muscle.

A new skin flap based on the cutaneous branches of the major nutrient vessel to the soleus muscle was designed and executed. An anatomic study of the major nutrient artery to the lateral half of the soleus muscle was performed on 26 legs. An angiographic study was performed on 27 legs. The major nutrient artery to the lateral half of the soleus muscle was classified according to its origin: the tibioperoneal trunk (type 1), the bifurcation of the posterior tibial and peroneal arteries (type 2), the posterior tibial artery (type 3), and the peroneal artery (type 4). The outer diameter of the major nutrient artery to the lateral half of the soleus muscle, by direct measurement, was 1.87 mm (range 1.1 to 2.5 mm). This new flap was applied in nine patients. The recipient sites were the great toe, the hand, the jaw, the anterior leg, the popliteal fossa, and the thigh. The vascular pedicle ranged from 6.5 to 9.5 cm in length. Tissue was transferred as a free flap in eight patients and as an island flap in one patient. All the flaps survived completely.

Adolescent↗
PubMed1994

Expression of the multidrug resistance gene (MDR1) in non-small cell lung cancer.

To ezamine the clinical relevance of P-glycoprotein, encoded by the human multidrug resistance gene (MDR1), to multidrug resistance in lung cancer, we examined the expression of MDR1 in 107 non-small cell lung cancer (NSCLC) specimens and 20 corresponding specimens of normal lung tissues. We also evaluated the relationship between MDR1 expression and the histopathology and pathological staging of NSCLC. The tumors consisted of 60 adenocarcinomas, 38 squamous cell carcinomas, 8 large cell carcinomas, and 1 adenosquamous carcinoma. MDR1 expression was semi-quantified by use of the reverse transcriptase-polymerase chain reaction method. We subclassified the NSCLC into 3 grades according to the MDR1 expression level (-, +, ++). Sixty-one of the 107 tumor specimens (57%) and 18 of the normal lung tissue specimens (90%) expressed various levels of the MDR1 gene. Only one tumor specimen showed higher MDR1 expression than the corresponding normal lung tissue. The relationship between pathological stage and MDR1 expression levels was not significant. These results suggest that the level of MDR1 expression in lung cells is decreased as cells progress from the normal to the transformed state.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Role of increased DNA synthesis activity of hepatocytes in multicentric hepatocarcinogenesis in residual liver of hepatectomized cirrhotic patients with hepatocellular carcinoma.

To examine whether the marked increase in DNA synthesis of hepatocytes in cirrhotic liver might elicit multicentric hepatocarcinogenesis, we examined the relationship between new development of hepatocellular carcinoma (HCC) and the bromodeoxyuridine (BrdU) labeling index (LI) of hepatocytes in the residual liver of hepatectomized patients with liver cirrhosis (LC) and HCC. Eighteen hepatectomized patients with LC and HCC, whose resected liver revealed neither portal nor hepatic vein invasion by histologic examination, were studied (to exclude cases with intrahepatic metastasis). DNA synthesis activity of hepatocytes from the residual cirrhotic liver was measured by a BrdU/anti-BrdU in vitro method. The incidence of HCC recurrence was studied during a 3-year follow-up period. Among 18 patients, 9 patients had recurrence and 9 did not. The average BrdU LI in the recurrent patients was 2.6 +/- 1.3% and was significantly higher than that in patients without recurrence (1.4 +/- 0.5%, P < 0.05). All five patients who had a BrdU LI of 2.4% or above showed recurrence within 3 years, as compared with 4 of 13 (30.8%) patients with BrdU LI of less than 2.4% (P < 0.05). Our data indicate that abnormally high DNA synthesis in hepatocytes in the background cirrhosis might lead to the development of multicentric carcinogenesis in human cirrhotic liver, and in the residual cirrhotic liver of hepatectomized patients with HCC and LC, it may be a predictor of new development of HCC.

Adult↗
PubMed1994

Distribution of epidermal growth factor and epidermal growth factor receptor in human lung: immunohistochemical and immunoelectron-microscopic studies.

The distribution of epidermal growth factor (EGF) and EGF receptor (EGFR) in adult human lung was examined by immunohistochemistry and immunoelectron microscopy. EGF immunoreactivity was observed in secretory granules and endoplasmic reticulum of serous acinar cells of bronchial glands. EGFR immunoreactivity was detected at the cell membrane of the basal cells and the bronchial surface nonciliated cells (indifferent cells) in the bronchus, the nonciliated bronchiolar cells (Clara cells) and the type II pneumocytes in peripheral lung. These results suggest that EGF is secreted into bronchial surface fluid from the bronchial glands and stimulates proliferation and/or differentiation of basal cells and indifferent cells of the bronchus, although the source of EGF responsive to Clara cells and the type II pneumocytes of peripheral lung was not determined.

Aged↗
PubMed1994

Familial congenital hypopituitarism with central diabetes insipidus.

Congenital hypopituitarism (CH) presenting with central diabetes insipidus is typically associated with midline facial deformities or ophthalmological abnormalities. We present three brothers with CH and central diabetes insipidus not associated with any of these predisposing conditions. All three subjects presented with clinical features typical for CH (neonatal hypoglycemia, short stature, protruding forehead, and microgenitalia). All had hypoplastic genitalia indicating in utero gonadotropin deficiency, and all had complete GH deficiency. One represented low levels of thyroid hormones and TSH, indicating central hypothyroidism. Water deprivation examination in two of the brothers demonstrated complete arginine vasopressin deficiency in one and partial deficiency in the other. Magnetic resonance imaging indicated absence of the pituitary stalk, severe hypoplastic anterior pituitary in all three brothers, and absence of any posterior pituitary gland in two of the three. The other sibling had an ectopic posterior pituitary. This first report of familial CH with central diabetes insipidus may represent a previously unknown midline anomaly and provide new insights into the genetic control of pituitary and hypothalamic development.

Antibodies↗
PubMed1994

Partial radiocarpal arthrodesis.

Eight patients underwent partial radiocarpal arthrodesis for various wrist disorders. There were 5 men and 3 women, whose age at operation ranged from 33 to 59 years with an average of 44 years. The indications for operation included post-traumatic changes secondary to distal radius fracture in 5 cases, Kienböck's disease in 1, Madelung's deformity in 1, and rheumatoid arthritis in 1. Arthrodesis was performed at the radiolunate joint in 5 cases, and at the radioscapholunate joint in 3 cases. In all cases, bone union was obtained within 3 months postoperatively. Postoperative wrist pain disappeared in 6 cases, and decreased in 2 cases. The average postoperative flexion-extension arc of motion was 35 degrees in the radioscapholunate arthrodesis group, and 85 degrees in the radiolunate arthrodesis group. The postoperative grip strength compared with the unaffected hand averaged 51% in the radioscapholunate arthrodesis group, and 68% in the radiolunate arthrodesis group. One patient showed a deterioration in the osteoarthritic change in the midcarpal joint.

Adult↗
PubMed1994

Effects of cross-sectional stress-relaxation on handling characteristics of suture materials.

Pullout friction and cross-sectional relaxation tests were conducted to quantitatively evaluate the handling characteristics of braided suture. The excellent handling of silk suture could be explained in terms of a large difference between static and dynamic pullout resistances. The difference in the resistance was closely correlated to the slope of the cross-sectional relaxation versus time logarithmic plot. It was therefore concluded that the cross-sectional stress-relaxation plays an important role in the handling performance of braided sutures.

Insect Proteins↗