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Biomedical subjects

Y Takimoto

Publications and source records attributed to Y Takimoto.

At least 37 records · Page 2Linked to original sources
PubMed1999

Intrathoracic esophageal replacement in the dog with the use of an artificial esophagus composed of a collagen sponge with a double-layered silicone tube.

OBJECTIVES: Intrathoracic esophageal replacement with an artificial esophagus is considered difficult. We attempted to replace the intrathoracic esophagus with an artificial esophagus composed of a collagen sponge with a double-layered silicone tube and examined the state of host tissue regeneration. METHODS: A 5-cm long gap was created in the intrathoracic esophagus in 9 dogs and repaired by interposition of our prosthesis. The dogs were fed only by intravenous hyperalimentation for 28 days. The silicone tube was removed at 29 days after the operation, and oral feeding was reintroduced. RESULTS: One dog was put to death at each of the following times: 1, 2, 3, 3, 6, 12, and 24 months after the operation. One dog is still surviving without problems after more than 26 months. One dog died of malnutrition at 10 months. In all dogs, the host regenerated tissue had replaced the resulting gap at the time of silicone tube removal. The mucosa had fully regenerated within 3 months and the glands within 12 months. The process of stenosis and shrinkage was complete within 3 months and did not advance thereafter. The lamina muscularis mucosae were observed as islets of smooth muscle within 12 months. Although the skeletal muscle regenerated close to the anastomoses, it did not extend to the middle of the regenerated esophagus even after 24 months. CONCLUSIONS: Use of a collagen sponge with a double-layered silicone tube was shown to be feasible even in the thorax and to allow the regenerated host tissue, consisting of the mucosa, glands, and lamina muscularis mucosae, to replace the esophageal gap.

Anastomosis, Surgical↗
PubMed1999

A sclerosant with astringent properties developed in China for oesophageal varices: comparison with ethanolamine oleate and polidocanol.

BACKGROUND: Xiao zhi ling (XZL), which consists of Chinese nutgalls and aluminium potassium sulphate, is used as a local injection for the treatment of internal haemorrhoids in China. It is also used for endoscopic sclerotherapy of oesophageal varices. To date, however, it has not been compared with other sclerosants with regard to its safety and efficacy. METHODS: In the present study, the effect on the endothelium and the haemolytic and thrombosing effects of XZL were compared with those of 5% ethanolamine oleate and 1% polidocanol, using an endothelial cell line and red blood cells taken from rats and the dorsal marginal ear vein of rabbits. In addition, XZL was injected into the area surrounding varices in rats and its efficacy was studied endoscopically and histologically. RESULTS: Xiao zhi ling reduced the size of varices in rats after causing severe damage in the injected region. Compared with the other two sclerosants, however, XZL had little effect on the endothelium and was the least haemolytic compound. Furthermore, XZL did not cause thrombosis in the injected vein of a rabbit. CONCLUSIONS: These results suggest that XZL is another type of sclerosant with astringent rather than detergent properties. This compound should be used to treat oesophageal varices by paravariceal injection in smaller doses than 5% ethanolamine oleate and 1% polidocanol.

Alum Compounds↗
PubMed1999

Facial nerve repair using a collagen conduit in cats.

We evaluated facial nerve regeneration using a collagen tube as a nerve conduit in five cats. In three 5 mm of the facial nerve were resected, a collagen tube was implanted, and a 5 mm segment of the opposite facial nerve was resected, reversed 180 degrees, and sutured back as an autologous nerve graft. In one a collagen tube was implanted on one side, and in the remaining one a 5 mm nerve segment was reversed. Histological, electrophysiological, and horseradish peroxidase labelling examinations were carried out 4-24 weeks postoperatively. Histological study showed that the nerve was well vascularised and regenerated. Electrophysiological examination confirmed the recovery of evoked electromyograms through to the regenerated axons. Horseradish peroxidase examination also confirmed restoration of the whole facial nerve. The collagen tube is an efficient nerve conduit.

Animals↗
PubMed1999

[The effect of 5-HT 2 antagonist for urinary frequency symptom on diabetes mellitus patients].

17 cases of patients with diabetes mellitus who had urinary frequency symptom for which anti-cholinergic agents proved ineffective were given Sarpogrelate Hydrochloride (Anplag), a selective 5-HT 2 receptor antagonist. Efficacy was judged using IPSS and QOL scores after 2 weeks medications, these showed that all cases had improved their urinary frequency during the days as well as the night. This was especially true for the QOL score. One time urinary volume markedly increased, but there was no statistical significance after medication in maximum flow rate and residual urine. At the same time, a separate group of 14 mainly BPH cases did not improve entirely. It is believed that reaction in the detrusor muscle with hyperreflexia of diabetes mellitus patients can reach 5-HT, and its reaction is believed to reach via the 5-HT 2 receptor. This paper is a first clinical report of making use of 5-HT 2 antagonist as hyperactive detrusor on diabetes mellitus patients.

Adult↗
PubMed1999

[Immunohistochemical study of p53 and Ki-67 antigen expression in bladder carcinoma].

We examined the relationship between the expression of mutant p53 and Ki-67 antigens in urinary bladder transitional cell carcinoma and the pathological and clinical findings. Tissues were obtained from 28 patients with bladder carcinoma who underwent total or partial cystectomy. An ABC immunostaining method and two primary antibodies (DO-7 and MIB-1 antibodies) were used. The percentages of p53 and Ki-67 antigen-positive cells to the total number of cells were regarded as the p53 and Ki-67 labeling indices (LI) respectively. There were no statistically significant correlations between p53 LI and the histological grade or stage, although p53 LI increased slightly in the high grade and high stage group. There was a statistically significant correlation between Ki-67 LI and the histological grade and stage (p < 0.05). The correlation between p53 LI and Ki-67 LI was linear. Some cases had a p53 LI below the mean even though the Ki-67 LI was higher. The clinical course was characteristic of superficial bladder carcinoma initially, but progressed to invasive bladder carcinoma over the next several years. These results suggest that even cases initially diagnosed as superficial bladder carcinoma with a low p53 LI may progress to invasive bladder carcinoma in subsequent years. Therefore, it is important that the patient be followed-up.

Aged↗
PubMed1999

Type 2B Hiroshima: a variant of von Willebrand disease characterized by chronic thrombocytopenia and the presence of all von Willebrand factor multimers in plasma.

Type 2B von Willebrand disease (vWD) is a von Willebrand factor (vWF) subtype with increased binding affinity for platelet glycoprotein (GP) Ib and is characterized by increased ristocetin-induced platelet agglutination at low concentrations of ristocetin. Usually there are no high molecular weight multimers of vWF, and platelet counts are within normal ranges in patients with type 2B vWD. We identified a variant of type 2B vWD showing the full range of vWF multimers in plasma accompanied by thrombocytopenia, which seemed to be caused by circulating platelet aggregation. Since the A1 domain and surrounding region of vWF alleles, in which mutation sites are known to be clustered in type 2B vWD, appeared normal on nucleotide sequencing, this increased binding affinity of vWF for GPIb may be due to a novel mechanism differing from that which usually underlies type 2B vWD.

Chronic Disease↗
PubMed1998

Biodegradation and tumorigenicity of implanted plates made from a copolymer of epsilon-caprolactone and L-lactide in rat.

Flat plates made from a copolymer of epsilon-caprolactone and L-lactide (P-CL-LA) [50:50 (w/w), molecular weight 1.62 x 10(5); 20 x 10 x 1 mm size] were subcutaneously implanted into 50 young, male Wistar rats (P-CL-LA group). After 24 months the plates had become a mass of small pieces, which were concentrated in an area of 3 x 2 x 1 mm. For comparison, 50 rats were implanted with medical-grade polyethylene plates (PE group) while another set of 50 rats was subjected to the same operation but without an implant (Sham Op group). Tumors arose in 25 rats from the P-CL-LA group: 24 were malignant mesenchymal tumors at the implant sites. In the PE group, tumors appeared in 16 rats (14 at the implant sites and two ectopically). The average tumor latency was 578+/-84 days in the P-CL-LA group and 452+/-102 days in the PE group. There was no difference in tumor incidence between the P-CL-LA and PE groups (p < 0.05). In the Sham Op group, two malignant tumors appeared over 2 years. Pathologically, these induced tumors arose from the inflammatory cells surrounding the degrading fragments of P-CL-LA within the tissue capsule. This indicates that relatively slowly degrading material can induce malignant tumors at a similarly high rate to nonabsorbable medical grade PE, at least in this animal model.

Abdominal Neoplasms↗
PubMed1998

The experimental replacement of a cervical esophageal segment with an artificial prosthesis with the use of collagen matrix and a silicone stent.

OBJECTIVE: Attempts have been made to replace esophageal defects with a variety of artificial materials. However, because of the artificial nature of the materials, problems such as infection, leakage, stricture, or dislocation could not be avoided. Therefore we have designed a new type of artificial esophagus that is gradually replaced by host tissue. METHODS: Our artificial esophagus was a two-layered tube consisting of a collagen sponge matrix and an inner silicone stent. We used it to replace 5 cm esophageal segmental defects in 43 dogs, and the inner silicone stent was removed endoscopically at weekly intervals from 2 to 4 weeks. RESULTS: In the 27 dogs from which the silicone stent was removed at 2 or 3 weeks, constriction of the regenerated esophagus progressed and the dogs became unable to swallow within 6 months. In the 16 dogs from which the silicone stent was removed at 4 weeks, highly regenerated esophageal tissue successfully replaced the defect, leaving no foreign body in the host. Moreover, the regenerated esophagi had stratified flattened epithelia, striated muscle tissue composed of an inner circular and an outer longitudinal muscle layer, and esophageal glands. CONCLUSIONS: Even in mature adult higher mammals, esophageal high-order structures can be regenerated provided that an adequate three-dimensional extracellular structure is put in place for a sufficient period.

Actins↗
PubMed1998

Gamma/delta T cell lymphoma presenting in the subcutaneous tissue and small intestine in a patient with capillary leak syndrome.

Peripheral T cell neoplasms originating from gamma/delta T cells are rarely reported, despite the development of hepatosplenic lymphoma from gamma/delta T cells. We report a case of multiple generated gamma/delta T cell lymphomas presenting in the subcutaneous tissue and small intestine in a patient with accompanying capillary leak syndrome. The patient, a 43-year-old male presented with remarkable systemic edema, pleural effusion, and ascites. Widespread tumors were evident in the subcutaneous tissue and in the small intestine. A biopsy revealed anaplastic large cell lymphoma in these lesions. Phenotypic examination showed that the neoplastic cells were positive for the surface markers CD3 and TCR delta, but negative for CD4, CD8 and TCR beta. Genomic analysis revealed a clonal rearrangement of the TCR genes encoding the gamma, delta, and beta chains. A polymerase chain reaction analysis of the gene encoding the TCR delta chain showed that the rearrangement occurred between V delta 3 and J delta 1, suggesting that neoplastic cells were generated in the early stages of T cell differentiation.

Adult↗
PubMed1998

Esophageal varices in rat models of liver cirrhosis.

Animal models resembling the human situation are very useful to investigate human disease. However, there has been no evidence of esophageal varices in rats with liver cirrhosis. In the present study, to determine whether intrahepatic portal hypertension produced by liver cirrhosis induces esophageal varices in rats, the esophagus was examined endoscopically in rat models of liver cirrhosis. All rats given carbon tetrachloride or thioacetamide and six of seven rats given a choline-deficient diet had esophageal varices or venous dilatation after 16 weeks of treatment, although the varices in one rat given carbon tetrachloride and in two rats given a choline-deficient diet were reduced from weeks 16 to 18. These findings suggest that timing is important when studying esophageal varices in rat models of liver cirrhosis. It is concluded that certain models of liver cirrhosis in rats could be used as models of esophageal varices due to intrahepatic portal hypertension.

Animals↗
PubMed1998

Indoor behavior and risk assessment following space spraying of d-tetramethrin and d-resmethrin.

To clarify the indoor behavior of insecticides in space spraying, an aerosol canister (containing a mixture of 0.45 g d-tetramethrin and 0.06 g d-resmethrin in a 300-mL product) was applied to a typical Japanese room under various conditions and temporal concentrations in air; floor, walls, and ceiling were monitored. Air concentrations were chiefly dependent on ventilation rates but not on air circulation by an air conditioner. During a periodic spraying, the airborne insecticides did not accumulate in the room, but the floor residues gradually increased with the number of sprayings. After cessation of spraying, however, dislodgeable residues on the floor decreased with time. The time-dependent behavior of d-tetramethrin was simulated by a mathematical model (InPest) developed by the authors, and it was found that the estimated values agreed fully with actually measured values. The simulation model also clarified the amount of insecticide evaporated from the room material, the amount vented to the outdoors, and so on. Indoor exposure levels of d-tetramethrin and d-resmethrin to the room's occupants were estimated with the monitored concentrations when a 10-sec spraying was done twice a day for 30 days. The margins of safety, which were obtained by dividing the no observed effect levels by the exposure levels, were over 100 for unclothed occupants, even in the room with the windows closed.

Adult↗
PubMed1998

Indoor behavior and risk assessment following residual spraying of d-phenothrin and d-tetramethrin.

To clarify the indoor behavior of insecticides in residual spraying equivalent to a crack and crevice treatment, an aerosol canister (containing a mixture of 0.9 g d-phenothrin and 1.1 g d-tetramethrin in a 300-mL product) was applied to a typical Japanese room under various conditions, and temporal concentrations in air and on the floor, walls, and ceiling were monitored. Air concentrations were chiefly dependent on ventilation rates but not on air circulation. During a periodic spraying, the airborne insecticides did not accumulate in the room, but the floor residues gradually increased with the number of sprayings. After cessation of spraying, however, dislodgeable residues on the floor decreased with time. The time-dependent behavior of d-phenothrin was simulated by a developed simulation model (InPest), which helped a more comprehensive understanding of the insecticide behavior. Indoor exposure levels of d-phenothrin and d-tetramethrin to room occupants were estimated with the monitored concentrations when a 2.5-min spraying was done four times over an 8-week period. The margins of safety, which were obtained by dividing the no observed effect levels by the exposure levels, were over 100 for unclothed occupants, even in a room with the windows closed.

Adult↗
PubMed1998

[Two cases of true hermaphrodite: the usefulness of laparoscopic gonadectomy in childhood. A case report].

Laparoscopic operation has been an alternative method in not only adults but children. We presented two children with true hermaphroditism who were performed by open gonadectomy and laparoscopic gonadectomy respectively. Both patients at the age of 4, and 2 years showed karyotypes of 46, XX, and were raised as girls. In the first case left ovary and right ovotestis were revealed by open gonadal biopsy and right ovotestis was removed by open surgery. In another case bilateral ovotestes were revealed by laparoscopic gonadal biopsy and resected by laparoscopic procedure. Laparoscopy was very useful for detecting the gonadal structures to confirm the diagnosis in intersex patients. True hermaphrodite is one of uncommon intersex anomalies, therefore the diagnosis should be made to demonstrate the coexistence of both ovarian and testicular tissues definitely. We estimated laparoscopic gonadectomy in pediatric true hermaphrodite and concluded that laparoscopic gonadectomy was as profitable as open gonadectomy.

Child, Preschool↗
PubMed1998

[Therapy-related MDS/leukemia carrying dup(11) (q21q23) with MLL gene tandem duplication].

A 42-year-old woman had been given a diagnosis of malignant lymphoma, follicular, small cleaved cell. She had undergone chemotherapy including etoposide (1,500 mg/total) and was in her second complete remission. Four years and 4 months later, refractory anemia with excess of blasts (RAEB) with dup(11) (q21q23) x 2 developed in the patient and progressed to acute myeloid leukemia (AML-M5b). Despite regression of the AML to RAEB, a clone with the additional abnormality of del(20) (q11q13.1) appeared and transformed the RAEB into AML-M6. Rearrangement of the MLL gene was observed, and FISH analysis demonstrated that the signal sequences from the gene's 5' and 3'-terminal regions had detached. RT-PCR techniques detected a tandem duplication of MLL gene exons 2 through 8. This was considered to be one of the mechanisms behind the formation of the 11q23 abnormality observed in this patient.

Adult↗
PubMed1997

High-sensitivity detection and postsource decay of 2-aminopyridine-derivatized oligosaccharides with matrix-assisted laser desorption/ionization mass spectrometry.

The sensitivities of oligosaccharide derivatives in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) were compared using two matrixes, 2,5-dihydroxybenzoic acid (DHBA) and alpha-cyano-4-hydroxycinnamic acid (CHCA). For this purpose, maltopentaose was tagged with 2-aminopyridine (PA), 4-aminobenzoic acid ethyl ester (ABEE), and trimethyl-(p-aminophenyl)ammonium chloride (TMAPA). DHBA was more advantageous for enhancement than CHCA. Among the derivatives, the sensitivity with the PA-tagged maltopentaose showed a 100-fold improvement over the native one with DHBA as a matrix, while the oligesaccharide derivatized with ABEE and TMAPA gave 30- and 10-fold increases in sensitivity over the underivatized one. To obtain structural information from these derivatized oligosaccharides, postsource decay (PSD) during flight in the field-free drift in MALDI-TOFMS was measured. Predictable and reproducible fragmentation patterns could be obtained in all cases. Furthermore, we found matrix-dependence fragmentation with the PA-labeled oligosaccharide. With CHCA, a simple spectrum ascribable to Y series ions was obtained. On the other hand, both B and Y series ions were clearly observed in the DHBA case. The results demonstrate the usefulness of derivatives for sensitive analysis of oligosaccharides with MALDI.

Aminopyridines↗
PubMed1997

Transcription regulation of the PDGF A-chain gene by first intron elements.

A cis-acting regulatory region within the first intron of the human platelet-derived growth factor (PDGF) A-chain gene has been identified that functions to negatively regulate transcription of PDGF A-chain promoter/CAT reporter constructs in both A172 and HeLa cells and that functions independent of position, orientation, and promoter context. Further dissection of this region revealed several independently acting negative regulatory elements that exhibited cell-type specificity. These results suggest that the first intron of the PDGF A-chain gene contains negative regulatory elements that may cooperate to regulate the cell-type specific expression of the PDGF A-chain gene.

Cloning, Molecular↗