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Biomedical subjects

T Yamaguchi

Publications and source records attributed to T Yamaguchi.

At least 721 records · Page 40Linked to original sources
PubMed1997

Increased apoptosis rate by hyperthermochemoradiotherapy for advanced rectal cancers.

Apoptosis induced in cancer cells by ionizing radiation, hyperthermia, and 5-fluorouracil (5-FU), termed "hyperthermochemoradiotherapy" (HCR), has been well studied in vitro; however, the role of apoptosis in the tumocidal effect of HCR for primary rectal cancers has not yet been clarified. Therefore, we examined the relationship between the therapeutic effect and induction rate of histological apoptosis in 16 patients with rectal cancers after HCR. Numerous Tunel-positive apoptotic cells were found in the tumor tissue after HCR, but few were found in the tumors which had not received HCR. The histological therapeutic effect was closely correlated to the rate of apoptosis. Thus, we suggest that HCR induces a therapeutic effect mainly through apoptosis in human rectal cancers.

Administration, Rectal↗
PubMed1997

Histometric analysis of the distal pancreas in pancreatic head cancer.

To clarify the histological status of the pancreas tail after pancreatoduodenectomy (PD), fibrosis, islets of Langerhans, and A, B, and D cells were examined histometrically in surgical cases of pancreatic cancer. The same investigations were also performed during an autopsy examination of the pancreas tail of survivors of surgery who had received either PD or total pancreatectomy with segmental autotransplantation (SAT). In the surgical cases, fibrosis and the islet percentage compared with nonpancreatic cancer cases were significantly higher while the B cell ratio was significantly lower. In addition, in pancreatic cancer patients, the fibrosis and islet ratio in the group with a blocked pancreatic duct were higher while the B cell ratio was lower than in the group with an open pancreatic duct. A direct relationship between the islet ratio and the degree of fibrosis, and an inverse relationship between the B cell ratio and the degree of fibrosis, were thus found. From the autopsy cases, the fibrosis progressed and the islet ratio increased following PD, but after SAT only the islet ratio increased compared to the time of surgery. The progression of fibrosis after PD thus suggests the presence of some problems in both the surgical method and postoperative management.

Adult↗
PubMed1997

The operative indications for proximal gastrectomy in patients with gastric cancer in the upper third of the stomach.

While proximal gastrectomy is often performed for early gastric cancer in Japan, it remains unclear whether or not proximal gastrectomy should be performed for advanced gastric cancer. This study was designed to determine the operative indications for proximal gastrectomy in patients with gastric cancer in the upper third of the stomach. A total of 1691 patients with gastric cancer were reviewed retrospectively from hospital records during the period from 1969 to 1994, and the clinicopathologic characteristics of 82 patients who underwent proximal gastrectomy were compared with those of 150 patients who underwent total gastrectomy. Lymph node metastasis along the lower part of the stomach was observed in gastric cancers which had invaded beyond the muscularis propria of the stomach, but not in those confined to the muscularis propria. Three patients with gastric cancer that had invaded beyond the muscularis propria and metastasized to nodes along the lower part of the stomach were cured by total gastrectomy. However, there was no difference in the postoperative survival rates of the patients treated with proximal gastrectomy and those treated with total gastrectomy, irrespective of tumor stage and depth of invasion. Thus, proximal gastrectomy should be performed for gastric cancer when the depth of invasion is confined to the muscularis propria of the stomach.

Aged↗
PubMed1997

Overexpression of bax sensitizes breast cancer MCF-7 cells to cisplatin and etoposide.

Bax, one of the bcl-2 family genes, is expressed in a number of untransformed cell lines and various breast tissues, whereas only weak or no expression has been detected in breast cancer cell lines and malignant breast tissue. Human breast cancer MCF-7 cells, which have a weak bax gene expression, were stably transfected with pCX2neo bax, encoding human bax; and two unique clones, MCF-7/bax-1 and MCF-7/ bax-2, that expressed different levels of bax were generated. Sensitivity to cisplatin (CDDP) and etoposide (VP-16) was examined and each stable transfectant was more sensitive to these agents than the parental MCF-7 cells. The degree of enhancement in sensitivity to these anticancer agents was dependent on the expression level of bax. The enzyme-linked immunosorbent assay (ELISA), which quantifies DNA damage, demonstrated that this sensitization was due to apoptosis. Thus, we suggest that exogenous bax-alpha overexpression may be one of the factors determining cellular chemosensitivity in MCF-7 breast cancer cells and that it could be applied therapeutically to enhance chemosensitivity in breast cancer cells.

Antineoplastic Agents↗
PubMed1997

Facilitation of acetylcholine release in rat frontal cortex by indeloxazine hydrochloride: involvement of endogenous serotonin and 5-HT4 receptors.

Effects of indeloxazine hydrochloride, an inhibitor of serotonin (5-HT) and norepinephrine (NE) reuptake with a facilitatory effect on 5-HT release, on acetylcholine (ACh) output in frontal cortex of conscious rats were characterized using an in vivo microdialysis technique. Systemic administration of indeloxazine (3 and 10 mg/kg, i.p.) increased ACh and 5-HT output in a dose-dependent manner. Depletion of endogenous monoamines by reserpine and of 5-HT by p-chlorophenylalanine, but not that of catecholamines by alpha-methyl-p-tyrosine, significantly attenuated the facilitatory effect of indeloxazine on ACh release. When applied locally by reverse dialysis, indeloxazine (10 and 30 microM) and the selective 5-HT reuptake inhibitor citalopram (10 microM), but not the NE reuptake inhibitor maprotiline (30 microM), increased cortical ACh output. Indeloxazine (10 mg/kg)-induced increase in ACh release was significantly inhibited by local application of the 5-HT4 receptor antagonists RS23597 (50 microM) and GR113803 (1 microM), while the 5-HT1A antagonist WAY-100135 (100 microM), 5-HT1A/1B/beta-adrenoceptor antagonist (-)propranolol (150 microM), 5-HT2A/2C antagonist ritanserin (10 microM) and 5-HT3 antagonist ondansetron (10 microM) failed to significantly modify this effect. Neither depletion of monoamines nor treatment with serotonergic antagonists significantly changed the basal ACh level, indicating that endogenous monoamines do not tonically activate ACh release. These results suggest that indeloxazine-induced facilitation of ACh release in rat frontal cortex is mediated by endogenous 5-HT and involves at least in part cortical 5-HT4 receptors.

Acetylcholine↗
PubMed1997

A mutation of the beta 3-adrenergic receptor is associated with visceral obesity but decreased serum triglyceride.

The Trp64Arg mutation of the beta 3-adrenergic receptor (beta 3AR) is prevalent in several ethnic groups and is associated with weight gain, and some features of syndrome X such as insulin resistance and dyslipidaemia. Nevertheless, it is not known at present whether this mutation is associated with visceral obesity, which is an important risk factor for the development of hypertension, dyslipidaemia, insulin resistance, non-insulin-dependent diabetes mellitus, and atherosclerosis. To investigate whether this mutation may contribute to visceral obesity, we studied the relationships between beta 3AR genotypes and clinical phenotypes. The Trp64Arg allele of beta 3AR was examined in 278 Japanese men with respect to variables relating to visceral obesity assessed by computerised tomography. To detect the Trp64Arg mutation, polymerase chain reaction-restriction fragment length polymorphism analysis using Bst NI digestion was performed. This mutation was more frequently observed in subjects with higher body mass index (BMI) (p = 0.02). Moreover, in 120 subjects with a moderate degree of obesity (22 < or = BMI < 26.4 kg/m2), the mutation (homozygotes and heterozygotes) was associated with visceral obesity (higher ratio of visceral to subcutaneous fat area; V/S) (p = 0.03). Furthermore, the Trp64Arg allele was more frequent in subjects with lower serum triglyceride levels (p = 0.02) and the Trp64Arg homozygotes, but not heterozygotes, exhibited lower triglyceride levels. Thus, this mutation appears to be associated with visceral obesity but with lower serum triglyceride. It is suggested that those with the mutation may describe a subset of subjects characterized by decreased lipolysis in visceral adipose tissue.

Adult↗
PubMed1997

Epithelioid sarcoma with unusual radiological findings.

The case of a patient with epithelioid sarcoma in the right arm is reported. The diagnosis was delayed because of misinterpretation arising from complexity in the MR findings, including a honeycomb pattern in the subcutaneous fat simulating lymphedema, and an intramuscular diffuse high signal intensity on T2-weighted images without a discrete mass lesion. The histological findings revealed that the diffuse muscular abnormality mainly resulted from denervation of the muscles due to perineural invasion by the tumor, and subcutaneous edema from lymphedema secondary to lymphatic tumor spread concurrent with lymphatic fibrosis. Multiple foci of cortical erosions in the humerus, a rare manifestation of this tumor, were detected 6 months later.

Arm↗
PubMed1997

Ewing's sarcoma of the thumb.

The case of a 51-year-old man with Ewing's sarcoma of the thumb is presented. The tumor involved the distal phalanx of the right thumb, associated with an impressive extraskeletal mass. Histology revealed a round cell sarcoma with a positive immunoreactivity with monoclonal antibody O13. Five years after disarticulation at the metacarpophalangeal joint, the patient is alive without recurrence or metastasis.

Bone Neoplasms↗
PubMed1997

Malignant fibrous histiocytoma arising from a calcifying enchondroma--a case report.

A man, 79 years of age, developed a malignant fibrous histiocytoma which arose in relation to a calcifying enchondroma of the distal femur. Radiographs showed a fracture through an intensely calcified bony tumour with no bony destruction. The clinical diagnosis was a dedifferentiated chondrosarcoma. Histology showed an anaplastic sarcoma with calcified tissue showing extensive areas of necrosis and degeneration. No chondrosarcomatous foci were found.

Aged↗
PubMed1997

Expression of basic fibroblast growth factor (FGF-2)-associated with tumour proliferation in human pancreatic carcinoma.

Basic fibroblast growth factor (FGF-2) is one of the mitogens that facilitate epithelial proliferation and angiogenesis. We analysed the expression of FGF-2 and type I fibroblast growth factor receptor (FGFR1) in 20 selected cases of human pancreatic carcinoma (PC) in connection with proliferation of tumour cells and intratumour endothelial cells (ECs), using immunohistochemistry and in situ hybridization (ISH). By FGF-2 immunostaining, tumour cells were strongly positive in 10 cases (50%). By FGFR1 immunostaining, stromal fibroblasts and ECs occasionally showed positive staining. Tumour cells in 12 cases (60%) were strongly positive. Expression of FGF-2 mRNA, as examined by ISH, was detected in 12 cases (60%) of PC, and its distribution pattern was similar to that of FGF-2 immunostaining. We divided these cases into two groups according to the result of FGF-2 immunostaining, and examined the Ki67 labelling indices of tumour cells and ECs between these two groups. These two proliferative indices were significantly higher in FGF-2-positive than in FGF-2-negative cases (P<0.05, P<0.05, respectively). These findings suggest that the expression of FGF-2 in PC is strongly associated with the proliferation of tumour cells and ECs and its increased expression may give tumour a growth advantage.

Carcinoma, Adenosquamous↗
PubMed1997

Sequence and phylogenetic analyses of highly virulent infectious bursal disease virus.

The nucleotide sequences of the genome segments A and B encoding the precursor polyprotein (NH2-VP2-VP4-VP3-COOH) and VP1 were determined for a highly virulent strain of infectious bursal disease virus (IBDV). The precursor polyprotein and VP1 coding regions of highly virulent OKYM strain consisted of 3039 nucleotides (1012 deduced amino acids) and 2640 nucleotides (879 deduced amino acids), respectively. Comparison of the deduced amino acid sequences of the highly virulent IBDV (HV-IBDV) with other serotype 1 and 2 sequences revealed 17 amino acid residues which were conserved only in the HV-IBDV. Among the 17 unique amino acid differences, 8 were in VP1, 4 were in VP2, 3 were in VP3 and 2 were in VP4. Although it is impossible to predict the effect of the unique amino acid residues without detailed knowledge of the three-dimensional structure and function of the proteins, they could affect the virulence of HV-IBDV. Alignment of the nucleic acid sequences of precursor polyprotein, VP1, VP2, VP3 and VP4 coding regions followed by distance analysis allowed the generation of phylogenetic trees. The same tree topology was obtained for the nucleotide sequence of precursor polyprotein, VP2, VP3 and VP4. On the other hand, the tree topology of VP1 was quite different from that obtained for the nucleotide sequence of precursor polyprotein, VP2, VP3 and VP4. These findings indicate that not a genetic recombination but a genetic reassortment may play an important role in the emergence of HV-IBDV.

Amino Acid Sequence↗
PubMed1997

The pharmacokinetics of water-in-oil-in-water-type multiple emulsion of a new tacrolimus formulation.

We developed a water-in-oil-in-water-type (W/O/W)-type multiple emulsion of a new tacrolimus formulation. A potential approach to avoid the complications of systemic immunosuppression and simultaneously enhance immunosuppressive efficacy is to deliver immunosuppressive agents locally to the site of the target organs. The W/O/W emulsion is dispersed oil drops containing smaller water droplets that allow the delivery of drugs preferentially to the reticuloendothelial systems (RES). Since the liver and the spleen are primary components of the RES, and the brain and the kidney have a poor RES, we hypothesized that a W/O/W emulsion of tacrolimus would possess the pharmacokinetic benefits of local immunosuppression. We evaluated this hypothesis in a rat model. The tacrolimus levels of whole blood, the liver, spleen, brain, and kidney in rats given intravenous emulsions of tacrolimus (W/O/W group) were compared with a group administered tacrolimus alone (T group). There were no significant differences between the pharmacokinetic parameters of W/O/W group and T group based on whole blood data. However, the W/O/W group had significantly decreased tacrolimus levels in the brain and kidney, and significantly increased levels in the liver and spleen compared with the T group. These data suggest that the W/O/W emulsion is applicable as an intravenous drug carrier for local immunosuppression.

Animals↗
PubMed1997

Successful surgical treatment of a complete traumatic tracheal disruption.

We report a case of a survivor who suffered a complete traumatic disruption of the cervical trachea associated with multiple organ injuries. She underwent an emergent operation including end-to-end anastomosis of the disrupted trachea with pedicled omental coverage to prevent dehiscence and mediastinitis. The postoperative course was uneventful, with hospital discharge on day 36. She returned to her previous lifestyle.

Anastomosis, Surgical↗
PubMed1997

LpA-I levels do not reflect pre beta1-HDL levels in human plasma.

High-density lipoprotein (HDL) containing apo A-I but no apo A-II (LpA-I) can promote cholesterol efflux from cells, while HDL containing apo A-I and apo A-II can not. Pre beta1-HDL, a minor fraction of LpA-I, is the initial acceptor of cellular cholesterol. To determine whether the pre beta1-HDL:LpA-I ratio is constant in human plasma, we measured LpA-I levels by differential electroimmunoassay, and HDL subfraction levels by nondenaturing 2-dimensional gel electrophoresis in 26 subjects. We found that the pre beta1-HDL:LpA-I ratio was higher in hypercholesterolemia (0.21+/-0.09; n = 11, P < 0.05), coronary artery disease (0.26+/-0.13; n = 5, P = 0.08) and hypertriglyceridemia (0.39+/-0.22; n = 3, P = 0.16) than in normolipidemia (0.11+/-0.03, n = 5). LpA-I levels were significantly correlated with HDL2b (r = 0.771, P=0.000001), HDL2a (r = 0.438, P < 0.01), and pre beta2-HDL levels (r = 0.496, P < 0.005) but not with pre beta1-HDL or HDL3 levels. In conclusion, the pre beta1-HDL:LpA-I ratio is not constant in human plasma. These findings strongly suggest that size distribution of LpA-I may change in various disorders.

Adult↗
PubMed1997

Giant negative U waves during acute myocardial infarction and ischemia.

Giant negative U waves transiently appeared in a patient with acute myocardial infarction (AMI). During hospitalization, these giant negative U waves (0.3-0.5 mV) were observed in leads V2 through V4 of the electrocardiogram (ECG). The waves disappeared 10 days after hospitalization, but reappeared during a treadmill exercise test 3 weeks after the onset of AMI. The same waves were detected again when the patient was admitted for angina pectoris 3 months later. Since these giant negative U waves appeared concomitant with myocardial ischemia, ischemia seems to be their cause. To our knowledge, there are no previous reports on reproducible U waves like those seen in this patient.

Aged↗
PubMed1997

Two cases of torsion of the gallbladder diagnosed preoperatively.

BACKGROUND: The authors experienced two cases of torsion of the gallbladder, both of which were correctly diagnosed preoperatively. METHODS: Two boys, aged 4 and 5 years, were transferred to Yokohama City Seibu Hospital because of their acute abdominal disorders. Diagnostic imaging demonstrated acute inflammatory changes in the gallbladder with an abnormal arrangement of the gallbladder and common bile duct in both cases. Laparotomy findings showed torsion of the gallbladder by 180 degrees and 360 degrees, respectively, at the cystic ducts, resulting in gangrenous change. RESULTS: Both children recovered uneventfully after cholecystectomy. The diagnostic imaging criteria are (1) collection of fluid between the gallbladder and the gallbladder fossa of the liver, (2) a horizontal rather than vertical arrangement of the long axis of the gallbladder, (3) the presence of a well-enhanced cystic duct located on the right side of the gallbladder, and (4) signs of inflammation including marked edema with thickening of the wall. CONCLUSIONS: The authors report the clinical characteristics of this uncommon condition, and discuss the significance of accurate preoperative diagnosis of these acute surgical disorders.

Child, Preschool↗
PubMed1997

Expression of human islet amyloid polypeptide/amylin impairs insulin secretion in mouse pancreatic beta cells.

Non-insulin-dependent diabetes mellitus (NIDDM) is associated histopathologically with islet amyloid deposits of which a major component is islet amyloid polypeptide (IAPP)/amylin. We examined whether endogenous IAPP controls insulin secretion via a local effect within pancreatic islets and whether overexpression of this peptide contributes to pancreatic beta-cell dysfunction in this disease. Transgenic mice expressing human IAPP in pancreatic beta cell were used in this study. Human IAPP expression did not influence the mouse proinsulin mRNA level and insulin content. Glucose-induced insulin secretion was decreased in the isolated pancreatic islets of transgenic mice. MIN6, a glucose-responsive pancreatic beta-cell line, was transfected with human IAPP cDNA by a lipofectin method. Human IAPP expression was confirmed by RNA blot and immunohistochemical analysis. In two transfectants expressing the largest amount of human IAPP, insulin secretion was increased in response to glucose stimulation; however, the magnitude of the insulin response in cells transfected with human IAPP was smaller than in control clones. Insulin content was not influenced by the expression. We conclude that endogenous IAPP inhibits insulin secretion via an autocrine effect within pancreatic islets, and that the impaired insulin secretion in this disease may be partly caused by overexpression of IAPP.

Amyloid↗