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Biomedical subjects

S Tamai

Publications and source records attributed to S Tamai.

At least 145 records · Page 8Linked to original sources
PubMed1996

Osteogenic potential of allogeneic rat marrow cells in porous hydroxyapatite ceramics: a histological study.

Hydroxyapatite ceramics facilitate osteogenesis but cannot induce bone formation by themselves. We studied the feasibility of bone formation supported by allogeneic bone marrow cells in porous hydroxyapatite ceramics. Coralline hydroxyapatite discs were soaked in a marrow cell suspension harvested from either ACI (RT1a), Lewis (RT1(1)), or Fischer 344 (RT1(1v)) male rats, and these discs were implanted subcutaneously into 56 male Fischer 344 rats. FK-506 (tacrolimus hydrate), an immunosuppressant, or saline was injected intramuscularly into the recipients every day for 2 weeks after surgery, and additional injections were given to 19 of the rats every 2 days for 2 more weeks. Neither of the mismatched major (ACI rat) or minor (Lewis rat) marrow cell transplants showed any bone formation without administration of FK-506. However, in rats treated with FK-506, bone formed in the pores of all the three types of ceramics implanted, which each contained the marrow cells from one of the three kinds of rats used. There were no differences among the three groups of donors with regard to the bone formation ratio. We previously reported that subcutaneous implantation of porous hydroxyapatite combined with isogeneic marrow cells resulted in consistent bone formation, even at ectopic sites. Since it would be difficult to harvest a large number of autologous marrow cells in clinical cases, we attempted to use allogeneic marrow cells and have shown the allogeneic murine marrow cells to have osteogenic potential.

Animals↗
PubMed1996

Adenoid cystic carcinoma of the esophagus: report of a case and review of the Japanese literature.

We report herein the case of a 79-year-old man with adenoid cystic carcinoma (ACC) of the esophagus. The tumor had a polypoid appearance and was covered by thin esophageal mucosa. As the biopsy specimens suggested a diagnosis of poorly differentiated adenocarcinoma, the patient underwent subtotal esophagectomy with reconstruction of the gastric tube via the posterior mediastinum. Histologically, the carcinoma contained basaloid cells, cribriform foci, and a certain amount of eosinophilic hyaline substance. Some of the basaloid cells were stained immunohistochemically for keratin, muscle actin, and S-100 protein, a pattern which was identical to the pattern of immunoreactivity of the myoepithelium. We reviewed 36 other cases of ACC of the esophagus reported in Japan, with special reference to the criteria for histological diagnosis.

Aged↗
PubMed1996

Molecular cloning of the mouse gene coding for carbonic anhydrase IV.

Carbonic anhydrase IV (CA IV) is expressed on apical surfaces of renal tubular epithelium and endothelium of specialized capillary beds. It plays a key role in bicarbonate reabsorption in kidney and in CO2 transport in other tissues. The human cDNA and genomic sequences have been cloned and characterized. Here we report the cloning and characterization of the entire mouse CA IV gene (contained in two overlapping lambda clones), which should enable generation of targeting constructs for disrupting the mouse CA IV gene to produce mouse models for in vivo analysis of CA IV gene function. The gene is approximately 8.2 kb long and contains eight exons ranging from 54 to 434 bp in length. The first exon (exon 1a) encodes the signal sequence. Exons 1b through 7 encode the remaining coding sequences. Exon 7 encodes the C terminus of the membrane-associated protein, as well as the 242-bp 3' untranslated sequence. The nucleotide sequence alignment between mouse and rat CA IV cDNAs reveals 84% identity. The nucleotide sequence alignment between mouse and human CA IV shows 69% identity in the coding region and all of the exon-intron boundaries are conserved, as are the sizes of the introns. The corresponding mouse and human exons are similar, except for the length of the untranslated regions in exons 1a and 7 and two small insertion/deletion events in exons 1a and 4. The 5' flanking region of the mouse gene (-300 to -1) is GC rich and contains 16 CpG dinucleotides. A TATA box sequence and several transcription factor binding sequences are identified upstream of exon 1a. Comparison of the nucleotide sequences surrounding the TATA box (-300 to -1) between mouse and human CA IV genes revealed 70% identity, indicating that regulatory sequences are as highly conserved as coding sequences between mouse and human CA IV genes.

Animals↗
PubMed1996

A case of skeletal dysplasia with advanced carpal ossification and "monkey wrench" appearance of the femora: mild Desbuquois dysplasia?

UNLABELLED: We report on a 14-year-old Japanese boy with radiographic features resembling those of Desbuquois dysplasia, including advanced carpal ossification, a "monkey wrench" appearance of the proximal femora, mild spondylar dysplasia, and generalized osteopenia. In contrast to the hitherto known patients with this disorder, however, his birth length was normal, and his short stature, which became apparent postnatally, was much milder than that of the previously reported cases (approximately -5 SD of average), and the joint laxity was more subtle. In addition, facial dysmorphism was absent, as were radial deviation of the second fingers and thoracolumbar kyphoscoliosis. CONCLUSION: The present patient may represent the mildest end of the variable phenotypic manifestation of the recently described Desbuquois dysplasia.

Adolescent↗
PubMed1996

Histological and biochemical evaluation of osteogenic response in porous hydroxyapatite coated alumina ceramics.

We compared the osteogenic response in porous alumni (Al) and hydroxyapatite coated porous alumni ceramic (HA/Al) by grafting rat bone marrow cells with these implants subcutaneously in the back of syngeneic rats. The ceramics did not show any bone formation without marrow, but did when combined with marrow cells. The osteogenesis in HA/Al began directly on the ceramic surface, but in Al began away from the ceramic surface, and fibrous tissue interposition was seen between the de novo bone and its surface. Alkaline phosphatase activity and bone specific bone gla protein content in HA/Al with marrow were both about three times higher than in Al with marrow. These results indicate that HA/Al has excellent osteoconductive properties and that a composite of marrow and HA/Al is clinically applicable osteogenic biomaterial.

Alkaline Phosphatase↗
PubMed1996

Pontine glioma with osteoblastic skeletal metastases in a child.

BACKGROUND: The development of systemic metastases from primary intracranial gliomas is rare. We report here a rare case of pontine glioma with osteoblastic skeletal metastases. CASE: This 12-year-old boy presented with a 4-month history of hoarseness, dysphagia, and a progressively ataxic gait. Cranial computed tomography (CT) and magnetic resonance imaging (MRI) revealed a brain stem tumor that was diagnosed as a low grade glioma by stereotactic biopsy. Twelve months later following chemotherapy and radiotherapy, neurologic examination and neuroradiologic studies disclosed a recurrence of the pontine glioma. Skeletal roentgenograms revealed widespread osteoblastic metastases in the skull, vertebral bodies, pelvis, and long bones. A specimen from the iliac bone demonstrated cells that were immunoreactive glial fibrillary acidic protein (GFAP). DISCUSSION: The mechanism of how glioma cells determine their biologic behavior at bony metastatic sites is not known. Infratentorial gliomas, which occur frequently in young patients and demonstrate active bony metabolism, may stimulate osteoblastic cells, and induce osteoblastic changes.

Bone Neoplasms↗
PubMed1996

Closed rupture of the flexor digitorum profundus tendon of the little finger caused by calcification of the triangular-fibrocartilage.

A case of rupture of flexor digitorum profundus tendon of the little finger caused by calcification of the triangular fibrocartilage (TFC) is reported. At operation, a round defect of the TFC and rupture of the flexor digitorum profundus tendon (FDP) of the little finger were observed. The defect of TFC was repaired using the palmaris tendon and FDP of the little finger was woven into FDP of the ring finger. Eleven months after operation, the patient had almost full flexion and extension of the distal and proximal interphalangeal joints.

Aged↗
PubMed1996

Innervated radial thenar flap for sensory reconstruction of fingers.

A radial thenar flap, which is supplied by the superficial palmar branch of the radial artery and innervated by the superficial branch of the radial nerve, was used in four patients for sensory reconstruction of the fingers. Two patients had degloving injuries of the hand and two had amputation injuries of the thumb. Three of the cases underwent free-flap transfers, and one case underwent a reverse-flow island flap. The size of these flaps was about 3 x 5 cm except in one case, where a 15 x 5 cm flap combined with a radial forearm flap was used. Sensory reinnervation was excellent and donor site morbidity was minimal in all four cases. An innervated radial thenar flap from the ipsilateral hand offers an alternative choice to reconstruct large palmar defects of the fingers.

Adolescent↗
PubMed1996

Histologic and biochemical analysis of osteogenic capacity of vascularized periosteum.

We analyzed the osteogenic capacity of the vascularized periosteum histologically and biochemically using a new experimental model of the vascularized tibial periosteum-hydroxyapatite composite in rats. Bone formation was observed not only on the surface but also in the pores of the hydroxyapatite at 4 weeks. The alkaline phosphatase activity increased to a peak at 2 weeks, with half this activity maintained until 8 weeks. The bone-specific bone gla protein content increased constantly as time passed. On the other hand, in the vascularized fascia-hydroxyapatite composite group (control group), no bone formation was observed histologically, alkaline phospatase activity was low, and bone gla protein content was very low. These results indicate that (1) the vascularized periosteum has the most significant osteogenic capaacity at 2 weeks, with a constant level of the activity maintained thereafter, (2) it forms new bone soon after operation, and (3) the amount of bone increases as time passes.

Alkaline Phosphatase↗
PubMed1996

Radical forearm flap with vascularized tendons for hand reconstruction.

We treated six patients with soft-tissue defects involving the skin and extensor or flexor tendons using a cutaneotendinous radial forearm flap. There were five male patients and one female patient. Their ages at operation ranged from 22 to 65 years (mean 50 years). In one patient, the flexor pollicis longus tendon was reconstructed with a palmaris longus tendon graft. Four patients each had two extensor tendons reconstructed. This was performed either with the palmaris longus tendon folded in the center (n = 2) or with the palmaris longus and flexor carpi radialis tendons (n = 2). In the remaining patient, three extensor tendons were reconstructed with the palmaris longus and flexor carpi radialis tendons. All the flaps survived. Recovery of motor function has been satisfactory in all but one patient.

Adult↗
PubMed1996

Localized malignant peritoneal mesothelioma containing rhabdoid cells.

A case is presented of localized malignant peritoneal mesothelioma appearing as a liver neoplasm. The patient underwent tumor resection but developed a recurrent growth and died 10 months after the initial surgery. The primary tumor showed sarcomatous features with rhabdoid cells. Examination revealed the presence of hyaluronic acid, co-immunoreactivity for cytokeratin epithelial membrane antigen and vimentin, cellular contacts with small desmosomes, and intracytoplasmic lumina. These findings supported the mesothelial nature of this tumor. The recurrent tumor was composed of predominantly tubulopapillary proliferation. It was concluded that the present tumor was a localized malignant mesothelioma of a biphasic type showing a predominantly sarcomatous component in the primary tumor.

Aged↗
PubMed1996

Isolated first naviculocuneiform joint coalition.

Clinical analysis was performed on 60 feet in 40 patients with isolated first naviculocuneiform coalitions. The most common symptom was a mild pain at the medioplantar site of the first naviculocuneiform joint. Fifteen feet (25%) were asymptomatic. Some cases had been treated erroneously as osteoarthritis or bony cyst before diagnosis. We divided coalitions morphologically into three patterns based on computed tomography findings: irregular, cystic, and combined pattern. Based on the mean age of each pattern, we hypothesized that initial irregular coalitions gradually develop into cystic and, finally, combined patterns. Considering the modest number of reported cases, this condition might easily be overlooked in many patients or may be related to ethnic characteristics. We suggest that the actual incidence of first naviculocunei-form coalitions should be investigated again.

Adolescent↗
PubMed1996

Japanese triplets with cerebrotendinous xanthomatosis are homozygous for a mutant gene coding for the sterol 27-hydroxylase (Arg441Trp).

We present the first case of triplets with cerebrotendinous xanthomatosis (CTX). A C-to-T base change identified in the genomic DNA and cDNA encoding the sterol 27-hydroxylase led to replacement of arginine by tryptophan at position 441 (Arg441Trp) in the triplets. The triplets were homozygous and their mother was heterozygous for this mutant gene. The triplets exhibited an identical phenotypic expression, which was different from that of a sporadic CTX case with the same mutation.

Adult↗
PubMed1996

[A device for rapid elevation of plasma methotrexate (MTX) concentration and its maintenance in high-dose MTX therapy].

For 5 osteosarcomas and one synovial sarcoma, 24 courses of high-dose methotrexate (MTX) therapy were performed. At MTX doses of 300 mg/kg with several infusion patterns, the plasma MTX concentrations were measured by fluorescence polarization immunoassay. In the various types of infusions, five hours oblique and five hours bolus infusions were well maintained at 1,000 micromol/l for several hours. In particular, five hours bolus infusion of MTX needed only 20 minutes to reach 822 micromol/l and maintained 1,000 micromol/l during almost the entire infusion period. Optimization of chemotherapy for sarcomas by MTX requires individual adaptation of the infusion pattern.

Adolescent↗