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Biomedical subjects

S Tamai

Publications and source records attributed to S Tamai.

At least 37 records · Page 2Linked to original sources
PubMed2001

Lipoprotein analysis using agarose gel electrophoresis and differential staining of lipids.

We established a strategy to directly measure cholesterol and triglyceride levels of each lipoprotein fraction using a combination of agarose gel electrophoresis and differential staining. The cholesterol and triglyceride levels determined by electrophoresis correlated significantly with those of ultracentrifugation. The correlation coefficients between these methods were, for cholesterol levels 0.975(very low density lipoproteins, VLDL), 0.986(low density lipoproteins, LDL) and 0.965(high density lipoproteins, HDL) and for triglyceride levels 0.994(VLDL), 0.963(LDL) and 0.959(HDL) respectively. Both intra-and inter-assays showed low values of coefficients of variation (CV) (less than 3.57%). We observed a strong linearity between staining and triglyceride concentration. An increased VLDL-cholesterol was observed in type III subjects, a result which enabled distinction between type III and type IIb or type V lipoproteinemia. The method revealed lipoprotein patterns in some samples otherwise unexpected from their corresponding serum lipid parameters. Analyses of these electrophoretic patterns thus provide an effective technique to classify types of hyperlipidemia defined by the WHO. Furthermore, quantitative measurement of chylomicrons, usually difficult, proved to be achievable, providing an additional analysis of postprandial hyperlipidemia and the exact measurement of LDL-cholesterol after diet. Consequently, we recommend this simple and easy method for clinical evaluation of abnormalities in lipoprotein profiles.

Chylomicrons↗
PubMed2001

Expression of L-type amino acid transporter 1 in a rat model of liver metastasis: positive correlation with tumor size.

The purpose of this study was to examine whether L-type amino acid transporter 1 (LAT1), one of the amino acid transporters, is related closely to tumor size in liver metastasis. Rat colon cancer cells (RCN-9) were injected into the capsule of the spleen of 12 male rats (inbred F344/DuCrj). Conversely, four rats received only phosphate-buffered saline (control group 1), and four rats underwent only laparotomy (control group 2). In each rat, the metastatic tumors, areas surrounding tumor nodules, or the livers of the control groups were immunostained with the antibodies to LAT1 C peptide antigen. In control groups 1 and 2, normal hepatocytes did not indicate a staining of LAT1. A total of 90 metastatic nodules were found in 12 livers with metastasis. Of the 90 metastatic nodules, 43 nodules indicated a positive staining of LAT1. Conversely, the remaining 47 metastatic nodules had a negative staining of LAT1. The average size in metastatic nodules in the group with positive staining of LAT1 was 1.6 +/- 0.4 mm2, which was significantly higher than that of the group with negative staining of LAT1 (0.6 +/- 0.2 mm2; P = .0007). The ratio of the average area of the metastatic nodule against the average largest section of the left lobe of the lateral segment (RML, %) was measured. The RML in the group with positive staining of LAT1 was 1.2 +/- 0.3%, whereas the RML in the group with negative staining of LAT1 was 0.4 +/- 0.1%. A significant difference was noted between the two groups (P = .0004). We concluded that LAT1 plays an important role in tumor cell growth of liver metastatic tumors.

Animals↗
PubMed2000

Clinical and radiographic evaluation of disc excision for lumbar disc herniation with and without posterolateral fusion.

STUDY DESIGN: A prospective study evaluating the clinical and radiographic results in 95 patients with lumbar disc herniation. OBJECTIVES: To evaluate the results of disc excision, with and without posterolateral fusion. SUMMARY OF BACKGROUND DATA: The effect of posterolateral fusion on the outcomes and radiologic changes in patients with lumbar disc herniation has rarely been reported. METHODS: Forty-four patients underwent disc excision, and 51 patients underwent disc excision and fusion. Clinical symptoms were evaluated using the Japanese Orthopaedic Association Back scores. All medical and surgical records were examined with regard to intraoperative blood loss, operation time, and other data. Preoperative and follow-up radiographs were analyzed to determine the spinal motion and disc height. RESULTS: Clinical outcome was excellent or good in 73% of the nonfusion group and in 82% of the fusion group (P = 0.31). The reduction in lower back pain after surgery was greater in the fusion group. The rate of recurrent disc herniation at the surgical level in the nonfusion group increased, but intraoperative blood loss, operation time, length of hospital stay, and total cost of procedure were all significantly less in the patients undergoing disc excision alone than in the fusion group. The radiologic analysis provided evidence that the disc height at the level of disc excision and posterolateral fusion in the fusion group decreased with time, as in the nonfusion group. The changes in disc height and spinal motion were not related to the clinical results. CONCLUSIONS: Although there is still controversy regarding the pros and cons of fusion in association with disc excision, there is seldom an indication for primary fusion for lumbar disc herniation.

Adolescent↗
PubMed2000

In vivo osteogenic durability of cultured bone in porous ceramics: a novel method for autogenous bone graft substitution.

BACKGROUND: Bone marrow cells differentiate into bone-forming osteoblasts when cultured in medium supplemented with 15% fetal bovine serum, ascorbic acid, beta-glycerophosphate, and dexamethasone. METHODS: To investigate in vivo osteoblastic activity and bone matrix formation by cultured bone marrow cells, Fischer rat marrow cells were cultured for 2 weeks in porous hydroxyapatite (HA) and then subcutaneously implanted into 7-week-old male syngeneic rats. The implants were harvested after 8 and 52 weeks for biochemical and histological analyses. RESULTS: At both times, formation of lamellar bone accompanied by regeneration of marrow were seen in many of the HA pores. When a fluorochrome (calcein) was administered at 50 weeks after implantation, it was detected in the pores of implants harvested at 52 weeks. Osteoclastic resorption followed by new bone formation was seen in some pores at 52 weeks, indicating that bone remodeling was continuing. The alkaline phosphatase activity of implants harvested at 52 weeks was comparable to that at 8 weeks, whereas the osteocalcin content of the implants harvested at 52 weeks was about twice that at 8 weeks. CONCLUSION: These results demonstrated that there was persistent in vivo osteogenic and hematopoietic activity in the prefabricated bone/HA constructs, and indicated that normal bone tissue was regenerated after grafting of the constructs, which were brittle before implantation. Tissue engineering using HA and cultured marrow cells culture may provide an alternative method of bone transplantation for patients with skeletal disorders, although further in vivo and in vitro experiments are needed.

Alkaline Phosphatase↗
PubMed2000

Progenitor endothelial cells on vascular grafts: an ultrastructural study.

The morphology of progenitor endothelial cells on vascular graft surfaces is addressed in this report. Such cells were seen to attach to intima-expressed CD34 and Flk-1 antigen and showed positive 5-bromo-2-deoxyuridine (BrdU) uptake. We examined CD34 and Flk-1 antigen-expressing endothelial progenitor cells three-dimensionally using confocal laser scanning microscopy (CLSM). Under detailed CLSM observation, through an ameboid-form cell, these progenitor endothelial cells changed from a globular to a flattened form. We also investigated these morphological changes using scanning electron microscopy. From these results, progenitor endothelial cells were observed not only near the advancing edge of endothelium, but also around the developing intimal site. Their form also changed from globular to flattened as observed in the CLSM results. These morphological changes were seen more frequently near the advancing edge and around the developing intimal site. They attached directly to vascular prosthesis fibers and likewise covered the graft luminal surface. Progenitor endothelial cells in any form had a common surface structure. We conclude from our results that progenitor endothelial cells can attach to graft fibers directly without clotting and directly cover the graft luminal surfaces.

Animals↗
PubMed2000

Flap transfers for the treatment of perichondrial ring injuries with soft tissue defects.

Seven cases (six fresh) of perichondrial ring injury with skin defects were treated using flap transfers. The study included four boys and three girls ranging in age from 2 to 9 years (average 6). They were followed up for an average of 8 years and 10 months. The period from injury to flap coverage was 8-12 days, with an average of 10 days in the fresh cases. Fracture was noted in four cases, with one an epiphyseal fracture. Peroneal flaps were transferred in four cases, latissimus dorsi myocutaneous flaps in two, and gastrocnemius muscle flap in one. Six flaps survived perfectly, and one failed due to venous thrombosis. This latter case was treated with a cross leg flap. Postoperative radiographic assessments confirmed partial growth plate arrest in the chronic case, but all the fresh cases had no postoperative growth disturbance. Flap coverage, for perichondrial ring injuries with wide skin defects, is a useful method not only for skin coverage, but for the prevention of growth disturbances as well.

Accidents, Traffic↗
PubMed2000

Indications and technique of sentinel lymph node biopsy in breast cancer using 99m-technetium labeled tin colloids.

BACKGROUND: The status of the sentinel lymph node (SLN) can reflect the status of other lymph nodes in breast cancer. The efficacy of dye injection and radiolabeled tin colloids for the accurate identification of the SLN was investigated. The indications for SLN biopsy for determining clinical nodal status were also investigated. METHODS: A total of 108 patients with breast cancers less than 5 cm were enrolled. Ninety-six patients were clinically node negative and 12 were node positive. About 2 hours before surgery, 1 to 2.5 ml of 99m-technetium-labeled tin colloid was injected around the tumor. Just before the operation, dye was also injected into the tissue surrounding the tumor. Six clinically node negative patients were omitted from the dye-injection process. The SLN was identified as a lymph node with extremely high radioactivity using a gamma probe or a gamma counter. Complete axillary dissection was performed and the metastatic status investigated by hematoxylin and eosin staining. RESULTS: In clinically node negative patients undergoing dye-injection, the SLN was identified in 89 of 90 patients (98.9%), and there was only one patient with lymph node metastasis outside the SLN. However, in clinically node positive patients undergoing dye-injection, the identification rate of the SLN was 66.7% (8 of 12 patients) and there was one patient with lymph node metastasis outside the SLN (12.5%). Without dye-injection, the SLN could be detected in 4 of 6 patients (66.7%). CONCLUSIONS: Successful identification of the SLN with tin colloid requires concomitant dye-injection and candidates for SLN biopsy should be restricted to clinically node negative cases.

Adult↗
PubMed2000

Bioabsorbable thread for tight tying of bones.

The purpose of this research was to develop a bioabsorbable thread for tight fixation of fractured bones and to examine its mechanical performance in an in-vitro simulation study. The thread is a blend of bioabsorbable poly(L-lactic acid); (PLLA) and poly(epsilon-caprolactone); (PCL) fibers and can be tightly connected by fusion welding of the PCL fibers. The tying strength of the PLLA-PCL blend thread was 39.7 N, which was comparable to that of stainless steel wire. A testing machine was fabricated to measure the fatigue strength of the tying by simulating bone fixation. The results showed that metal wires always failed because of breakage within 25,000 loading cycles, whereas the blend threads did not fail until 50,000 loading cycles. The looseness of tying for simulated bone fixation by the blend thread was within 1mm even after 50 000 loading cycles. In-vivo testing using rats revealed that the blend thread did not cause any severe inflammatory reaction.

Animals↗
PubMed2000

Morphologic changes of the ankle in children as assessed by radiography and arthrography.

Chronological changes in the morphology of the ankle, a joint that consists primarily of chondral components in children, were investigated by arthrography and plain radiography. Arthrography was performed in 57 ankles of 40 patients with normal ankles (aged from 2 months to 3 years, 4 months; mean, 1 year, 7 months), and plain radiography was performed on 183 joints of 126 patients with normal ankles (aged from 3 years, 6 months to 14 years, 5 months (mean, 7 years, 8 months). The angle of the distal tibial joint surface was then measured on each radiograph. Despite being evident at birth, valgus inclination in the ankle rapidly changed during the first and second years of life. Thereafter, change continued gradually and spontaneously, and the ankles were in the neutral position by 3 years of age. However, the morphology of the ankles did not change much after that time. Normal ankles show valgus inclination at birth, but this configuration is changed naturally over time, and the ankles are in the neutral or slightly varus position by the age of bone maturity.

Adolescent↗
PubMed2000

Collateral sprouting mechanism after end-to-side nerve repair in the rat.

The collateral sprouting mechanisms of axons from an uninjured donor nerve after end-to-side nerve repair was investigated in motor nerves of rats, with special reference to the neurotrophins related to nerve regeneration. In addition, growth cone formation at the tip of the regenerating nerve was examined. A transected medial gastrocnemius nerve (MGN) was transferred to the side of an intact lateral gastrocnemius nerve (LGN) using a Y-shaped silicone tube. At 3, 7, or 14 days later, the MGN with the LGN was transected and was stained immunohistologically. Expression of neurotrophin-3 (NT-3) and Trk C (receptor of NT-3) was most significantly observed 3 days postoperatively around the site of coaptation. Brain-derived neurotrophic factor (BDNF) and Trk B (receptor of BDNF) was weakly detected at the coaptation site 3 days after-operation. Growth-associated protein 43 (GAP-43), which is a marker of growth cone formation, was observed at the site of coaptation in the LGN 7 days postoperatively and in the MGN at the site of coaptation at 14 days. We concluded that motor nerve regeneration due to collateral sprouting of axons after end-to-side nerve repair is possible. We thus demonstrated the involvement of at least one neurotrophin, NT-3, in the process of collateral sprouting of motor nerves.

Animals↗
PubMed2000

Chondrosarcomatous differentiation in metastatic deposit of serous papillary cystadenocarcinoma.

A rare case of serous papillary cystadenocarcinoma of the ovary showing chondrosarcomatous differentiation in a metastatic deposit late in the clinical course is reported. A 49-year-old female underwent a total abdominal hysterectomy with bilateral salpingo-oophorectomy for bilateral ovarian tumors. Histological diagnosis was serous papillary cystadenocarcinoma of both ovaries with lymph node metastasis. After six courses of chemotherapy, she was confirmed to be in complete remission following a second laparotomy. Following additional chemotherapy, a third laparotomy disclosed swollen left inguinal lymph nodes. In one of these nodes, approximately 5.0 cm in greatest diameter, the predominant histological features were: chondrosarcoma of the bone and soft tissue, with small foci of serous papillary adenocarcinoma and squamous epithelium. A histological transition between mesenchymal and epithelial areas was identified. Immunohistochemical positivity for broad-spectrum cytokeratin (AE1/AE3), vimentin, epithelial membrane antigen, and S-100 protein was observed in both chondrosarcomatous and epithelial areas. The current evidence may suggest that the chondrosarcomatous differentiation was derived from the metastatic epithelial component.

Cell Differentiation↗
PubMed2000

Primary small cell (oat cell) carcinoma of the breast: report of a case and review of the literature.

A case of primary small cell (oat cell) carcinoma of the breast in a 41-year-old woman is presented. The patient was alive and well without disease 16 months after modified radical mastectomy and subsequent chemotherapy. The tumor cells revealed morphologic similarity to oat cell carcinoma of the lung and immunohistochemical expression of neuroendocrine markers. In ultrastructural examination, the tumor cells had neurosecretory granules. Review of nine previously reported cases and this case of primary small cell carcinoma of the breast has revealed that this type of tumor shows prominent vascular invasion, frequent lymph node metastasis, infrequent expression of estrogen receptor, and also very poor prognosis. Immunohistochemical study for the c-kit proto-oncogene product, which has been reported to be a specific marker for pulmonary small cell carcinoma, demonstrated positive reactivity in approximately 80% of the tumor cells of this case, which is the first report according to our knowledge. The expression of c-kit might be some aid to the diagnosis of primary small cell carcinoma of the breast.

Adult↗
PubMed2000

Vacuolated cell mesothelioma of the pericardium resembling liposarcoma: a case report.

We report a case of localized pericardial mesothelioma with unusual histological features in a 44-year-old woman. Her radiological imagings showed an 11-cm pericardial tumor, between the heart and aortic arch. Microscopically, the tumor was predominantly composed of vacuolated cells and vaguely reminiscent of well differentiated "lipoma-like" liposarcoma, but only small foci of the tumor showed the papillotubular configuration. Histochemically, the tumor cells contained hyaluronic acid in the vacuoles but no lipids. Immunohistochemically, they showed immunoreactivity for cytokeratin, calretinin, vimentin, and epithelial membrane antigen. Ultrastructural study showed that the vacuoles of the tumor cells were intracytoplasmic lumina. The intracytoplasmic lumina and the surface membranes of the tumor cells had many long and slender microvilli with focal bush-like appearance. Desmosomes between adjacent cells were occasionally observed. To our knowledge, this is the first case report of epithelial type mesothelioma predominantly composed of vacuolated tumor cells, microscopically mimicking liposarcoma.

Adult↗
PubMed2000

Microvascular anastomoses using an Nd-YAG laser.

The authors performed anastomoses of small vessels with the Nd-YAG laser, comparing these with conventional suture anastomoses. Some arteries were sutured with 10-0 nylon with about eight suture sites, and others were held by stay sutures at three points with laser irradiation performed between them. Two surgeons performed the anastomoses in the same way. The first was well-trained and experienced, and the second was technically inexperienced. The authors evaluated clamping time, patency rate, and endoscopic and histologic findings. The patency rate of the first surgeon was 100 percent (30/30) in the suture anastomoses and was 97 percent (29/30) in the laser anastomoses. For the second surgeon, the rates were 60 percent (18/30) in the suture group and 80 percent (24/30) in the laser group. On histologic examination, the suture group showed inflammatory cells around the suture site at the fourth week after the operation. In the laser group, an inflammatory reaction around the suture material was observed, but the other areas recovered. For the experienced surgeon, the patency rate and clamping time of the laser anastomosis provided no statistically significant difference to those of the suture anastomosis. On the other hand, for the inexperienced surgeon, the patency rate of the laser anastomosis was superior to that of the suture anastomosis, and the clamping time of the laser anastomosis was shorter than that of the suture anastomosis. Therefore, the authors concluded that the Nd-YAG laser anastomosis is useful for small vessels.

Anastomosis, Surgical↗
PubMed2000

Sensory reconstruction in sensate radial forearm flap transfer.

The authors treated 14 patients (13 men and one woman), using a sensate radial forearm flap. Their ages at operation ranged from 27 to 67 years (mean: 52 years). Preoperative conditions were amputations in 10 cases, degloving injury in three, and crush injury in one. Reconstructive sites involved the thumb in nine cases, the mitten-like hand in two, the index finger in one, the ring and small finger in one, and the palm in one. In all cases, the radial forearm flap, including the lateral antebrachial cutaneous nerve, was harvested. Sensory evaluation was performed using the moving two-point discrimination test (m-2PD). Sensation in the mid-palmar area of 50 forearms was examined in 25 healthy adult volunteers as a control group. Follow-up periods ranged from 12 to 87 months (mean: 39.6 months). The mean m-2PD of the 14 sensory flaps was 13.2 mm, and the mean of 50 forearms in the control group was 18.08 mm. A statistically significant difference was demonstrated between the sensory flaps and the 50 forearms of the control group. The mean m-2PD was much more sensitive in the innervated radial forearm flaps than in the donor forearm. The results suggested that sensory return in the innervated flaps is influenced not by the donor nerve in the flaps, but by the recipient digital nerve.

Adult↗
PubMed2000

A reverse ulnar hypothenar flap for finger reconstruction.

A reverse-flow island flap from the hypothenar eminence of the hand was applied in 11 patients to treat palmar skin defects, amputation injuries, or flexion contractures of the little finger. There were three female and eight male patients, and their ages at the time of surgery averaged 46 years. A 3 x 1.5 to 5 X 2 cm fasciocutaneous flap from the ulnar aspect of the hypothenar eminence, which was located over the abductor digiti minimi muscle, was designed and transferred in a retrograde fashion to cover the skin and soft-tissue defects of the little finger. The flap was based on the ulnar palmar digital artery of the little finger and in three patients was sensated by the dorsal branch of the ulnar nerve or by branches of the ulnar palmar digital nerve of the little finger. Follow-up periods averaged 42 months. The postoperative course was uneventful for all patients, and all of the flaps survived without complications. The donor site was closed primarily in all cases, and no patient complained of significant donor-site problems. Satisfactory sensory reinnervation was achieved in patients who underwent sensory flap transfer, as indicated by 5 mm of moving two-point discrimination. A reverse island flap from the hypothenar eminence is easily elevated, contains durable fasciocutaneous structures, and has a good color and texture match to the finger pulp. This flap is a good alternative for reconstruction of palmar skin and soft-tissue defects of the little finger.

Adult↗