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Biomedical subjects

Y Seto

Publications and source records attributed to Y Seto.

At least 19 recordsLinked to original sources
PubMed1999

An operative procedure for advanced Kienböck's disease. Excision of the lunate and subsequent replacement with a tendon-ball implant.

Excision of the lunate and subsequent replacement with a tendon implant was performed in 22 patients with Kienböck's disease between 1971 and 1985. This procedure was indicated mainly for those with advanced Kienböck's disease, i.e., stage III or IV according to the Lichtman classification. After the collapsed lunate is removed, a tendon-ball implant, made of the palmaris longus and plantaris tendons is placed in the resultant space in the carpus. A forearm distractor is applied during the operation, and distraction is continued for 4 weeks postoperatively. We report the long-term results in 15 patients, whose average follow-up period was 16 years and 3 months. One patient with infection was excluded from the study because the implanted tendon was removed 2 weeks after the operation, and 6 patients were lost to follow-up. All patients were free of pain after the surgery. The flexion-extension range of the wrist increased by 14.2 degrees, on average, after the surgery. The average grip power of the operated hand was 90.2% of that in the non-operated hand. Calcification and ossification were frequent in the implanted tendons a few months postoperatively. The average carpal height ratio (defined as carpal height/length of the third metacarpal) was 0.53 before the operation and 0.49 at the time of follow-up. According to Dornan's classification of clinical results, 9 of the 15 patients were classified as having excellent results and 6 as good.

Adult↗
PubMed1999

Association of plasma triglyceride-rich lipoprotein remnants with coronary atherosclerosis in cases of sudden cardiac death.

Among the risk factors for coronary atherosclerosis, elevated LDL-C level is best known. The action of lipoprotein lipase on triglyceride-rich lipoproteins produces remnant lipoprotein particles enriched in cholesterol and apolipoprotein E (apo E). Apo E serves as the ligand for uptake of remnant lipoproteins via the LDL-receptor or the remnant receptor. In this study, postmortem plasma total cholesterol, triglycerides (TG), VLDL-C, HDL-C, lipoprotein (a) [Lp(a)] and remnant-like lipoprotein particles (RLP)-cholesterol, RLP-TG, apolipoproteins B, C III and E were measured, together with LDL-C to assess their potential contribution to the severity of coronary and aortic atherosclerosis of the 197 cases of sudden death (132 cardiac death and 65 non-cardiac death). In all cases, the severity of coronary atherosclerosis was determined at postmortem pathological examination. RLP-cholesterol (RLP-C) and LDL-C concentrations were significantly higher in cases with advanced coronary atherosclerosis compared with those without coronary atherosclerosis; respective median values were 13.5 vs 8.4 mg/dl (P < 0.001) and 140 vs 115 mg/dl (P < 0.05). RLP-C levels were more strongly correlated with the severity score of coronary atherosclerosis than LDL-C.

Adult↗
PubMed1999

Effect of 5-fluorouracil on gastrointestinal carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine in rats.

This study was undertaken to determine the effect of 5-fluorouracil on gastrointestinal carcinogenesis. Sixty rats were divided into three groups of 20 rats each. All rats were exposed to N-methyl-N'-nitro-N-nitrosoguanidine for the first 20 weeks. Group 1 rats received intraperitoneal injections of 5-fluorouracil for the first 20 weeks and were then observed for the second 20 weeks. Group 2 rats also received 5-fluorouracil injections, but for the second 20 weeks. Group 3 rats received no 5-fluorouracil treatment. Four of 20 rats in group 1 developed an invasive adenocarcinoma. In group 3, invasive squamous cell carcinoma and adenocarcinoma developed in one rat each. None of the group 2 rats had malignant lesions. These results suggested that 5-fluorouracil is not effective in suppressing the initial stage of gastrointestinal carcinogenesis with a coexisting carcinogen. Rather, the therapeutic effect is exerted in later stages of tumor progression.

Adenocarcinoma↗
PubMed1999

Preliminary report on local resection with lymphadenectomy for early gastric cancer.

BACKGROUND: The frequency of lymph node metastasis in mucosal gastric cancers 2-4 cm in diameter was low (three (1.3 per cent) of 234) in patients treated in this unit between 1966 and 1995. This study was a prospective report on local resection with lymphadenectomy for early gastric cancer. METHODS: Eight patients with a single early gastric cancer underwent local resection with lymphadenectomy. The tumour was excised with a non-cancerous rim of approximately 2 cm. The extent of lymphadenectomy depended on tumour location. Intraoperative endoscopic examination and frozen-section analysis of the dissected nodes were used to determine the resection line and evaluate nodal status. RESULTS: Mean operating time, blood loss and number of dissected nodes were 171 min, 87 ml and 8 respectively. There were no operative complications. Cancer invasion was confined to the mucosa in six tumours but two patients had minute submucosal invasion. The maximum diameter of the resected specimens was 10 cm and no nodal involvement was detected. No patient developed postgastrectomy syndrome. CONCLUSION: For selected patients with early gastric cancer, local resection with lymphadenectomy can provide a good quality of life without compromising cure rate.

Adult↗
PubMed1999

Prefabricated free jejunal transfer: a new reconstructive technique for high pharyngeal defects.

A new method that uses a prefabricated free jejunal transfer has been applied to three cancer patients with pharyngoesophageal defects with a high pharyngeal deficit extending up to the nasopharynx. In this method, the jejunum harvested in the usual manner is divided into two segments with a single vascular pedicle. Its distal segment is used to reconstruct the cervical esophagus, and its proximal segment is turned over to create a mucosal patch to cover the high pharyngeal defects. The two segments are then co-apted in a side-by-side anastomosis. The esophagus can be reconstructed in a naturally straight shape without a curved portion or blind loop formation, thus leading to good swallowing function. In our series, all grafts survived well and there was no complication directly related to jejunal transfer. All patients could tolerate a soft diet without difficulty. This method is easy to perform and applicable to any shape or size of very high pharyngeal defects that cannot be reconstructed properly by other methods. Although patients with an advanced hypopharyngeal cancer usually have a poor prognosis, this technique allows a better quality of life for a probable short life span.

Aged↗
PubMed1998

Effect of cation-exchange pretreatment of aqueous soil extracts on the gas chromatographic-mass spectrometric determination of nerve agent hydrolysis products after tert.-butyldimethylsilylation.

The efficiency of pretreatment of aqueous soil extracts using a cation-exchange resin has been investigated by gas chromatographic-mass spectrometric (GC-MS) determination of nerve agent hydrolysis products after tert.-butyldimethylsilyl (TBDMS) derivatization. An aqueous solution containing methylphosphonic acid (MPA) and its monoalkyl esters, ethyl methylphosphonic acid, isopropyl methylphosphonic acid and pinacolyl methylphosphonic acid, was dried, and these phosphonic acids were derivatized with N-methyl-N-(tert.-butyldimethylsilyl)trifluoro-acetamide and analyzed by GC-MS. The yields of TBDMS derivatives were significantly decreased by the addition of calcium and magnesium ions to an aqueous solution (approximately 0.5 mM) before derivatization. The extent of lowered yields was related to the hydrophilicity of phosphonic acids. MPA and its monoalkyl esters were spiked into soil samples (sand, alluvial soil and volcanic ash soil), extracted with distilled water, dried, silylated and applied to GC-MS. The yields of TBDMS derivatives of monoalkyl esters from soil samples were low (3-42%) and MPA derivative was scarcely detected (yield: < 0.7%). By desalting the aqueous soil extract by passage through a strong cation-exchange resin, the yields of TBDMS derivatives of monoalkyl esters were significantly improved (12-69%) and MPA derivative was detected (yield: 2-36%). The extent of improved yields was related to the concentrations of divalent metal cations in aqueous soil extracts. In combination with desalting by the cation-exchange resin, GC-MS after TBDMS derivatization enables detection of nerve agent hydrolysis products in soils at sub-ppm (0.2 microgram/g) concentrations.

Acetamides↗
PubMed1998

Determination of Aconitum alkaloids in blood and urine samples. II. Capillary liquid chromatographic-frit fast atom bombardment mass spectrometric analysis.

Determination of fourteen alkaloids, toxic Aconitum alkaloids, aconitine, mesaconitine, jesaconitine, hypaconitine and deoxyaconitine, and their hydrolysis products, benzoylaconines and aconines, have been established using capillary liquid chromatography (LC) fast atom bombardment mass spectrometry (FAB-MS) with a frit interface. Protonated molecular ions were observed as base peaks in the FAB-MS for these fourteen alkaloids. All the alkaloids were simultaneously quantified with linear gradient LC elution by solvent mixture of acetonitrile and 0.3% trifluoroacetic acid using selected ion monitoring of the protonated molecular ions. The calibration curves of these alkaloids were linear in injection amounts ranging from 5 to 500 pg, and their detection limits were 1 pg per injection (S/N=3). Solid-phase extraction using Sep-Pak Plus PS-1 was also investigated to clean-up and concentrate alkaloids in blood and urine samples, and showed satisfactory recoveries. This capillary LC-frit-FAB-MS method enables determination of low levels of Aconitum alkaloids in blood and urine samples, coupled with solid-phase extraction.

Aconitine↗
PubMed1998

Occlusive effects of lactic acid-glycolic acid copolymer membrane on gingival fibroblasts in vitro.

The cell occlusive effects on human gingival fibroblasts of degradable lactic acid-glycolic acid copolymer membranes (noncoated membranes) and membranes coated with a sucrose ester of fatty acid (coated membranes) were studied and compared with those of expanded polytetrafluoroethylene (e-PTFE) membranes. The membranes were immersed in a culture medium periodically for 21 days and interposed into a chemotaxis chamber, and the fibroblasts then were cultured in the chamber for another 7 days. The passage rate of cells through the membranes was calculated and the change in surface structure of each membrane after immersion for 28 days was observed by an environmental scanning electron microscope. The passage rate of coated membranes (3.4+/-2.2%) was significantly lower than that of noncoated (25.7+/-5.1%) at the 28th day whereas the passage rate of e-PTFE membranes was 0.8-1.5%. Many pores were observed on the noncoated membranes before immersion while the coating material covered most of the pores on the coated membranes. The average pore size of the noncoated membranes was larger than that of the coated membranes at day 28. The structure of the e-PTFE membranes underwent no change. The passage rate of the coated membranes was not different from the e-PTFE membranes, suggesting an effect that might be useful for a guided tissue regeneration procedure.

Fibroblasts↗
PubMed1998

Complete dissection of the lymph nodes located along and at the roots of the left gastroepiploic vessels during distal gastrectomy.

Achieving complete dissection of the lymph nodes located at the roots of the left gastroepiploic vessels is difficult when distal gastrectomy is the surgical goal; firstly, because the short gastric vessels must be preserved to supply blood to the remnant stomach; and also, because the roots of the left gastroepiploic vessels at the splenic hilus are obscured intraoperatively by adipose tissues. We describe herein a technique which enables complete and easy dissection of the lymph nodes located along and at the roots of the left gastroepiploic vessels.

Gastrectomy↗
PubMed1998

Quantitation of herpes simplex viral DNA in Vero cells for evaluation of an antiviral agent using the polymerase chain reaction.

A method for quantitation of the DNA of Herpes simplex virus type 2 (HSV-2)-infected Vero cells by the polymerase chain reaction (PCR) was developed. This method allowed recognition of several molecules of viral DNA among the total DNA extracted from cells. The method could be applied to a very large range (10(-0)-10(-7)) of initial amounts of template. Products of PCR were collected after each cycle for kinetic analysis. Products were subjected to electrophoresis and amplified bands were stained with ethidium bromide. The intensity of fluorescence of each band was measured with a charge-coupled device (CCD) image analyzer. The time course of increases in the relative yield of viral DNA was determined. Two-fold amplification of viral DNA occurred each 6-h cycle from 7 h after infection. Using this method, the yields of viral DNA after treatment with the drug acyclovir (ACV) at 0.1 and 2 microg/ml were about 1/10 and 1/80 of those from nontreated infected cells, respectively. These results indicate that this method makes clear the inhibitory effect of ACV on the synthesis of viral DNA.

Acyclovir↗
PubMed1998

Epitope analysis of monoclonal antibodies to human Gc globulin (vitamin D-binding protein).

Gc globulin, also called vitamin D-binding protein, is a human 56 kDa plasma protein. Antigenic epitopes of the protein recognized by 12 different monoclonal antibodies (MoAbs), including the previously prepared MoAb E12 of which binding to Gc is inhibited by actin, were analyzed in relation to the functional domains of the protein. To map the epitopes recognized by the respective antibody, the reactivities of the MoAbs were tested by immunoblotting against the recombinant Gc fragments expressed in E. coli cells, and then a competitive ELISA was performed. The results showed that the antibodies were classified into at least six groups. Furthermore, in addition to E12, actin inhibited the reactivity of MoAb 21, of which the epitope was located within residues Asp320 to Glu379, in an ELISA in the presence of the ligand. This result must indicate that this antibody-binding site is near the site that interacts with actin. In contrast, no inhibitory effect by 25-hydroxyvitamin D to any antibodies was observed. Furthermore, all antibodies, including E12 and 21, reacted with membrane-bound Gc of lymphocytes by an immunofluorescence study, suggesting that Gc is unlikely to bind to the plasma membrane in its interaction with actin.

Actins↗
PubMed1998

Supplementation of Bifidobacterium longum to a high-fat, low-calcium diet lowers cytolytic activity of fecal water in rats injected with 1,2-dimethylhydrazine dihydrochloride.

The effects of supplementing Bifidobacterium longum SBT 2928 and Lactobacillus acidophilus SBT 2062 to a high-fat, low-calcium diet on bile acid concentration, fatty acid concentration, cytolytic activity and intestinal alkaline phosphatase (ALP) activity of fecal water in rats injected with and without 1,2-dimethylhydrazine dihydrochloride (DMH) were examined. Male Wistar rats at 8 weeks of age were fed a diet containing 18% coconut oil, 2% corn oil and 0.1% calcium for 15 d. Lyophilized cultures were supplemented to test diets at a concentration of 1%. The feeding of a high-fat, low-calcium diet elevated the bile acid concentration, cytolytic activity and ALP activity of fecal water as compared to the AIN-76A diet, whereas the fatty acid concentration was not changed. None of the cultures had any effect on these parameters. Furthermore, 8 week-old rats were given a single subcutaneous injection of DMH at 40 mg/kg body weight, and fed the same diets for 15 d. The DMH injection had no effect on the bile acid concentration but increased the fatty acid concentration and cytolytic activity of fecal water. In contrast, ALP activity was lower in the DMH-treated rats than in the non-treated rats. The ingestion of B. longum lowered cytolytic activity but had no effect on the bile acids, fatty acids and ALP activity of fecal water. L. acidophilus had no effect on these parameters.

1,2-Dimethylhydrazine↗
PubMed1998

Sudden natural death in driving: case studies in the western area of Kanagawa.

To assess their incidence and implications, we made a retrospective study of sudden unexpected natural deaths during driving that occurred in the five year-period between 1992 and 1997. During that period, 188 postmortem examinations were performed on driver victims of traffic accidents. Of these, 15 (8%) were found to have died of natural causes such as heart disease or cerebral hemorrhage. Marked findings in this study were that no persons over 70 years of age and more occupational drivers suffered natural death. Although no passengers or pedestrians were injured, as many as eight vehicles collided with another object or vehicle. Sudden natural death, particularly from cerebral hemorrhage, of drivers might be hazardous to other road users.

Accidents, Traffic↗
PubMed1997

Determination of Aconitum alkaloids in blood and urine samples. I. High-performance liquid chromatographic separation, solid-phase extraction and mass spectrometric confirmation.

Determination of four toxic Aconitum alkaloids, aconitine, mesaconitine, hypaconitine and jesaconitine, in blood and urine samples has been established using high-performance liquid chromatography (HPLC) combined with ultraviolet absorbance detection, solid-phase extraction and mass spectrometry (MS). These alkaloids were hydrolyzed rapidly in alkaline solution (half lives (t1/2) five months) and were unstable in solutions of methanol and ethanol (t1/2<one month). These alkaloids were separated on an octadecylsilica column with isocratic elution using a solvent mixture of tetrahydrofuran and 0.2% trifluoroacetic acid (14:86, v/v), which was found to be the optimal solvent of the elution systems examined. Calibration curves with UV detection were linear on injection of amounts ranging from 2.5 to 500 ng, and the limit of detection was 1 ng (S/N=3). These four alkaloids in aqueous solution were recovered almost totally by solid-phase extraction using the styrene polymer resin, Sep-Pak Plus PS-1, and were eluted using a mixture of acetonitrile and hydrochloric acid. These Aconitum alkaloids were confirmed by HPLC coupled with fast atom bombardment MS, giving their protonated molecular ions as base peaks. These alkaloids were detected by HPLC with UV detection from blood samples spiked with more than 50 ng ml(-1) of alkaloids, but were not detectable from urine samples spiked with 5 microg ml(-1) of alkaloids because of severe sample interference.

Aconitine↗
PubMed1997

Nicotinamide derivatives as a new class of gastric H+/K(+)-ATPase inhibitors. 1. Synthesis and structure-activity relationships of N-substituted 2-(benzhydryl- and benzylsulfinyl)nicotinamides.

A new series of N-Substituted 2-(benzhydryl- and benzylsulfinyl)nicotinamides 7 and 8 were synthesized. Upon acid activation in the acidic environment of the parietal cell, these compounds are converted into their active forms, 2,3-dihydro-3-oxoisothiazolo[5,4-b]pyridines 5, which inhibit gastric H+/K(+)-ATPase. Inhibitory activities against [14C]aminopyrine accumulation stimulated by dibutyryl cAMP in isolated rabbit parietal cells in vitro and histamine-induced gastric acid secretion in pylorus-ligated rats by intraduodenal administration in vivo were evaluated, and the structure-activity relationships were examined. Among the compounds synthesized, 2-[(2,4-dimethoxybenzyl)sulfinyl]-N-(4-pyridyl)nicotinamide (8b) showed potent inhibitory activities in vitro and in vivo equivalent to those of omeprazole, a typical H+/K(+)-ATPase inhibitor. Moreover, 8b was much more stable at neutral and weakly acidic pH than omeprazole, lansoprazole, and pantoprazole. Compound 8b is considered to be a promising agent for treating acid-related gastrointestinal disorders.

Aminopyrine↗
PubMed1997

Correlation of patient immune responses with genetically characterized small round-structured viruses involved in outbreaks of nonbacterial acute gastroenteritis in the United States, 1990 to 1995.

Small round-structured viruses (SRSVs) are a genetically and antigenically diverse group of caliciviruses that are the most common cause of outbreaks of acute nonbacterial gastroenteritis. We have applied both molecular techniques to characterize SRSVs in fecal specimens and serologic assays using four different expressed SRSV antigens to examine the distribution of outbreak strains in the United States and determine if the immune responses of patients were strain specific. Strains from 23 outbreaks of SRSV gastroenteritis were characterized by reverse transcription-PCR and nucleotide sequencing of a 277-base region of the capsid gene. These strains segregated into two distinct genogroups, I and II, comprising four and six clusters of strains respectively, each representing a distinct phylogenetic lineage. Serum IgG responses in patients were measured by enzyme immunoassay using expressed capsid antigens of Norwalk virus (NV), Toronto virus (TV), Hawaii virus (HV), and Lordsdale virus (LV), representing four of the 10 clusters. While strains in genogroups I and II were antigenically distinct, within genogroups, the specificity of the immune response varied greatly. Patients infected with genogroup I strains which had as much as 38.5% aa divergence from NV demonstrated relatively homologous seroresponses to the single NV antigen. In contrast, in genogroup II, homologous seroresponses to TV and HV were only present when the infecting strains showed less than 6.5% aa divergence from these antigens. These results suggest that TV and HV represent not only separate genetic clusters in genogroup II but also separate antigenic groups, each of which is related but distinguishable. In addition, two genetically distinct SRSV strains were identified for which we have no homologous antigen. This study suggests that while current molecular diagnostics are capable of detecting the full range of SRSVs, additional expressed antigens will be required to detect an immune response to SRSV infection caused by all the antigenically diverse strains.

Acute Disease↗
PubMed1997

Impact of lymph node metastasis on survival with early gastric cancer.

The impact of lymph node metastasis on the survival of early gastric cancer (EGC) cases remains controversial. A retrospective study of 621 patients with EGC undergoing gastrectomy with lymphadenectomy during the period 1966-1993 was performed to evaluate the influence of node involvement on long-term outcomes. Lymph node metastasis was observed in 63 cases (10.1%). Two groups, EGC with and without node involvement, were compared with respect to long-term results and various clinicopathologic factors. The median observation period was 123 months. EGC cases without metastatic nodes had significantly better outcomes than those with node involvement in terms of overall survival as well as survival excluding deaths due to diseases unrelated to the primary EGC. Survival rates for EGC patients with node involvement did not, however, differ significantly according to the number of metastatic nodes. Three factors-submucosal invasion, large tumor size, and recurrence-were significantly related to lymph node metastasis. Age, sex, family history of malignancy, histologic type, and multiple occurrence of gastric cancer were unrelated to the prevalence of node involvement. The frequency of recurrence in EGC cases without node involvement was low (1.8%, 10 of 558). Recurrence was not, however, exceptional in those with metastatic nodes (9.5%, 6 of 63). EGC patients with lymph node metastasis, even with only a single positive node, constitute a high risk group for EGC recurrence.

Aged↗