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J Yamamoto

Publications and source records attributed to J Yamamoto.

At least 127 records · Page 7Linked to original sources
PubMed1998

Helical computed tomography in the diagnosis of portal vein invasion by pancreatic head carcinoma: usefulness for selecting surgical procedures and predicting the outcome.

OBJECTIVE: To evaluate the use of helical computed tomography (CT) in diagnosing portal vein (PV) invasion by pancreatic head carcinoma and its usefulness in predicting outcome. DESIGN: Validation cohort study. SETTING: Tertiary care public hospital. PATIENTS: Twenty-seven patients with carcinoma involving the pancreatic head were preoperatively studied with helical CT. All patients underwent resection. MAIN OUTCOME MEASURE: By quantifying the contact between the tumor and PV on helical CT, the relationship between them was classified into 1 of 4 types: type 1, visible fat layer between PV and the tumor; type 2, with the total PV circumference defined as 360 degrees, contact between the tumor and PV was considered to be 90 degrees or less; type 3, contact ranged between 91 degrees and 180 degrees; and type 4, contact greater than 180 degrees. Helical CT results were compared with intraoperative observation, histological findings of the resected specimen, and postoperative course. RESULTS: When helical CT showed type 3 or 4, the case was diagnosed as positive for PV invasion. Sensitivity, specificity, and overall accuracy were 83%, 100%, and 89% when compared with the intraoperative assessment, and 92%, 79%, and 85% with the histological assessment, respectively. One- and 2-year survival rates were 86% and 69% for type 1, 100% and 75% for type 2, and 33% and 12% for type 3, respectively. The survival rates of patients with types 1 and 2 were significantly higher than that of those with type 3 (P<.05). All 3 patients with type 4 died within 9 months. CONCLUSIONS: Helical CT facilitates detection of PV invasion by pancreatic head carcinoma. The extent of PV involvement reflected the outcome after pancreatectomy.

Adenocarcinoma↗
PubMed1998

Small polypoid lesions of the gallbladder: differential diagnosis and surgical indications by helical computed tomography.

OBJECTIVES: To demonstrate the helical computed tomographic (CT) features of small polypoid lesions of the gallbladder and to establish a clinical strategy based on CT findings for the treatment of such lesions. DESIGN: Validation cohort study. SETTING: Tertiary care public hospital. PATIENTS: Thirty-one patients with polypoid lesions of the gallbladder (< or = 3 cm) underwent CT followed by resection. MAIN OUTCOME MEASURE: The detectability of the lesions on both unenhanced and enhanced CT and the configuration of the lesions on enhanced CT were prospectively evaluated in comparison with the histopathological findings. RESULTS: Unenhanced CT detected 14 (45%) of the 31 lesions, whereas enhanced CT detected all of the lesions. The detection rates of the neoplastic lesions (adenoma, adenocarcinoma, and metastatic tumor) and cholesterol polyps were 81% (13/16) and 7% (1/15), respectively (P<.001). Among the 20 lesions demonstrated as pedunculated, 6 (30%) were neoplastic, whereas 10 (91%) of the 11 lesions demonstrated as sessile were neoplastic (P<.001). When a lesion was demonstrated on unenhanced CT or its shape was sessile on enhanced CT, the case was diagnosed as a neoplastic lesion. The sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy of the CT diagnosis of the neoplastic lesions were 88% (14/16), 87% (13/15), 88% (14/16), 87% (13/15), and 87% (27/31), respectively. CONCLUSION: Computed tomography can differentiate neoplastic and nonneoplastic small polypoid lesions of the gallbladder and reliably identify the presence of neoplastic lesions that should be resected.

Adult↗
PubMed1998

Early hepatocellular carcinoma as an entity with a high rate of surgical cure.

Early hepatocellular carcinoma (HCC) has been defined as a well-differentiated cancer containing Glisson's triad, but it remains unknown whether this lesion is curable. We prospectively studied 70 patients (enrolled from 1,172 referrals between 1982 and 1991) who had a diagnosis of a single HCC 2 cm or less in diameter (Stage T1) and who underwent curative hepatectomy and long-term follow-up (range, 0.2 to 14.3 years). Patients were eligible for surgery if they had a tumor that met the diagnostic criteria for HCC and were in Child-Pugh class A (n = 59) or B (n = 11) status. Among the 70 patients, there was 1 operative death. Based on our typing system, the tumors were assigned as early HCC (n = 15), overt HCC (n = 52), and non-HCC tumor (n = 3). The rate of microscopic regional spread was lower in early HCCs than in overt HCCs (7% vs. 42%; P = .01). The early HCC group had a longer time to recurrence than did the overt HCC group (3.9 vs. 1.7 years; P < .001) and had no local recurrence. After a median follow-up of 6.3 years, both overall survival and recurrence-free survival in the early HCC group were significantly better than those in the overt HCC group (P = .01; P = .001). In these two groups, the 5-year rates of overall survival were 93% and 54% (P = .01), and those of recurrence-free survival were 47% and 16% (P = .05), respectively; a significant survival benefit persisted over a decade (57% vs. 21%; P = .05). The early HCC group was at a lower risk of recurrence (relative risk, 0.31; 95% CI, 0.15 to 0.65; P = .002) and death (relative risk, 0.26; 95% CI, 0.09 to 0.73; P = .01) than was the overt HCC group. Early HCC is a distinct clinical entity with a high rate of surgical cure, thereby justifying its definition. It can be a lesion that corresponds to "Stage 0" cancer in other organs.

Carcinoma, Hepatocellular↗
PubMed1998

Composite glandular-neuroendocrine carcinoma of the hilar bile duct: report of a case.

We report herein an unusual case of a composite glandular-neuroendocrine carcinoma of the hilar bile duct. A 71-year-old Japanese woman was admitted to our hospital suffering from general fatigue, progressive jaundice, and a high fever. Computed tomography and angiography findings revealed a solid hypervascular mass in the hepatic hilus. Thus, a subsegmentectomy of the liver (S4, S5) and bile duct resection with lymph node dissection were performed. A tumor measuring 6.0 x 3.0 cm was found to be located in the bile duct of the hepatic hilus. Histologically, the tumor was composed of well-differentiated adenocarcinoma and small cell neuroendocrine carcinoma cells, with a histological transition between the two components. Grimelius' method revealed the presence of diffuse positive tumor cells in neuroendocrine carcinoma. The neuroendocrine tumor cells were also diffusely immunoreactive to chromogranin A. To the best of our knowledge, only 22 previous cases of composite glandular-neuroendocrine carcinoma in the biliary tract have been reported; however, this is the first case report of a clearly composite tumor of the hilar bile duct.

Adenocarcinoma↗
PubMed1998

Nonfunctioning islet cell tumors of the pancreas: clinical, imaging and pathological aspects in 16 patients.

BACKGROUND: Nonfunctioning islet cell tumors (NFICTs) usually reach a large size prior to detection, at which stage patients have some symptoms or signs. Recently, NFICTs have been discovered in asymptomatic patients with increasing frequency owing to advances in diagnostic imaging techniques. This study investigated clinical, imaging and pathological features in recent cases of NFICT. METHODS: The medical records, radiographs and pathological specimens of 16 patients with NFICT who were evaluated between April 1991 and March 1996 were reviewed. RESULTS: Tumor sizes ranged from 0.8 to 17 cm (average, 5.2 cm). Five patients (31%) had some symptoms or signs at the time of diagnosis; however, the other 11 (69%) had no symptoms. Of 10 patients with a tumor of size 5 cm or less, nine were asymptomatic and all tumors were histologically benign. In contrast, in six patients with a tumor larger than 5 cm, four had some symptoms and five tumors were malignant. The detection rates of pancreatic tumor mass on ultrasonography and computed tomography were 94% (15/16) each. All 14 patients in whom the tumor was completely resected survived without recurrence; however, the remaining two patients with liver metastases died following recurrence. CONCLUSIONS: US and CT are useful in detecting NFICTs even if the tumor is small and the patient is asymptomatic. The detection of NFICTs of small size and their complete removal are essential for a successful cure.

Adenoma, Islet Cell↗
PubMed1998

A neurotrophic pyrimidine compound, MS-818, enhances EGF-induced restoration of gastric epithelial wounds in vitro.

MS-818 is a novel synthetic pyrimidine compound that stimulates nerve regeneration and promotes synthesis of various growth factors and differentiation of astrocytes. Effects of MS-818 on gastric epithelial cells were assessed using a wound repair model with primary cultured gastric epithelial cells from rabbits. A round wound with a constant cell-free area was created and the process of restoration was monitored by measuring wound size every 12 h. Cell proliferation was monitored by sequential staining with BrdU. As previously reported, EGF (10 ng/ml) accelerated wound repair by promoting cell migration and proliferation. Although MS-818 alone had no effects, MS-818 (10-100 microM) enhanced EGF-induced acceleration of gastric epithelial restoration, including cell migration and proliferation. Although the detailed mechanism of action of this agent is still unclear, MS-818 might have favorable effects on in vivo gastric mucosal repair.

Animals↗
PubMed1998

Psychotherapy in the Pacific Rim countries.

Ever since Freud created psychoanalysis over 100 years ago, it has been popular, especially in the USA. However, biological psychiatry is now at the forefront and the emphasis is on neurosciences and pharmacotherapy. Still, the question remains, what place is there for psychotherapy in psychiatric practice? We need to be aware of the need for psychotherapy for some patients. This has been scientifically demonstrated in the study of patients with moderate and severe major depression. It has been convincingly shown that there is a place for interpersonal therapy and for cognitive behavioral therapy. Moderately depressed patients may benefit from a regimen of psychotherapy. In contrast, those with severe depression also need antidepressant medication. Because people in the Pacific Rim countries are heterogeneous, their requirements may be diverse. Asian populations need emphasis on the family as a part of the treatment team. Biological and cultural issues also enter the picture. Using the example of the flushing response, 25% of Koreans versus 50% of the Han Chinese and Japanese have the flushing response. Confucius' teachings have influenced Chinese, Koreans and Japanese for over 2000 years. The need for therapy and education is great. One solution is in primary and secondary prevention with cognitive behavioral classes such as the depression prevention course.

Asia, Southeastern↗
PubMed1998

Cross-cultural epidemiology.

Two issues led me into the area of cross-cultural psychiatric epidemiology in the 1980s. The National Institute of Mental Health funded the Epidemiological Catchment Area Studies. One of them included a study of a Caucasian and Hispanic populations in Los Angeles. Dr Masaaki Kato, then the Director of the National Institute of Mental Health of Japan, was the consultant for a JAICA-funded project in Lima, Peru. He was interested in fostering psychiatric research there, so I suggested an epidemiological study. This study was done in two phases with Drs Shunichiro Hayashi, Kimpei Minobe and Alberto Perales. Because it is extraordinarily expensive to undertake epidemiological studies in the USA, I met with colleagues regarding psychiatric epidemiological studies in Asia, Dr Chung-kyoon Lee at the Seoul National University in Korea, Dr Eng-Kung Yeh of the National Taiwan University in Taipei,Taiwan, Dr Char-nie Chen of the Chinese University of Hong Kong, and Dr Masaaki Kato in Japan. Studies have been completed in Korea, Taiwan, Hong Kong, but not in Japan. In the meantime, very small pilot studies among Asian groups in Los Angeles were performed. The very recent results of the study of Chinese in Los Angeles, California, with the Composite International Diagnostic Interview are now available to compare the prevalence of selected psychiatric disorders among the Chinese in Los Angeles and the data from the National Co-Morbidity Study.

Adolescent↗
PubMed1998

L* protein of the DA strain of Theiler's murine encephalomyelitis virus is important for virus growth in a murine macrophage-like cell line.

Strain GDVII and other members of the GDVII subgroup of Theiler's murine encephalomyelitis virus (TMEV) are highly virulent and cause acute polioencephalomyelitis in mice. Neither viral persistence nor demyelination is demonstrated in the few surviving mice. On the other hand, strain DA and other members of the TO subgroup of TMEV are less virulent and establish a persistent infection in the spinal cord, which results in a demyelinating disease. We previously reported that GDVII does not actively replicate in a murine macrophage-like cell line, J774-1, whereas DA strain productively infects these cells (M. Obuchi, Y. Ohara, T. Takegami, T. Murayama, H. Takada, and H. Iizuka, J. Virol. 71:729-733, 1997). In the present study, we used recombinant viruses between these strains of the two subgroups to demonstrate that the DA L coding region of DA strain is important for virus growth in J774-1 cells. Additional experiments with a mutant virus indicate that L* protein, which is synthesized out of frame with the polyprotein from an additional alternative initiation codon in the L coding region of TO subgroup strains, is a key determinant responsible for the cell-type-specific restriction of virus growth. L* protein may play a critical role in the DA-induced restricted demyelinating infection by allowing growth in macrophages, a major site for virus persistence.

Animals↗
PubMed1998

Relationship between hippocampal theta-wave frequency and emotional behaviors in rabbits produced with stresses or psychotropic drugs.

The hippocampal EEG power spectra of rabbits were analyzed to clarify the relationship between the theta-wave and emotionality. The relative power of T2 (6.0-7.9 Hz)/T1 (4.0-5.9 Hz) represented the index of theta-wave change. Emotional excitement (produced with novelty stress or methamphetamine) or suppression (produced with restraint stress or reserpine) increased or decreased T2/T1 ratios within around +/- 1 Hz changes. Furthermore, the imaging patterns of the peak feature make possible detailed characterization of emotional states. These results suggest that the hippocampus finely adjusts the theta-wave on a +/- 1 Hz level, with a fine balance of voltage, in response to the emotional activity.

Animals↗
PubMed1998

Protective effect of GTS-21, a novel nicotinic receptor agonist, on delayed neuronal death induced by ischemia in gerbils.

The neuroprotective effects of GTS-21 [3-(2,4-dimethoxybenzylidene)-anabaseine dihydrochloride] were studied and compared with those of nicotine, 9-amino-1,2,3,4-tetrahydroacridine hydrochloride hydrate (THA) and pentobarbital-Na (PB) using a cerebral ischemia model in Mongolian gerbils. The learning performance and memory retention were elucidated by a step-through passive avoidance task at 2 and 3 days after ischemia-reperfusion. In this task, the ischemia-operated gerbils showed impairment of learning performance and memory retention. Neuronal cell death in the hippocampal CA1 area was observed at 7 days after ischemia. When administered i.p. 30 min before ischemia, GTS-21 (5 mg/kg), (-)-nicotine (1.5 mg/kg), THA (5 mg/kg) and PB (50 mg/kg) significantly attenuated the impairment of passive avoidance performance and the neuronal cell death induced by the ischemia. When administered orally twice daily for 2 weeks prior to the ischemia, GTS-21 (10 mg/kg) significantly suppressed both amnesia and neuronal cell death, while (-)-nicotine (10 mg/kg) and THA (10 mg/kg) suppressed only the amnesia. These results suggest that GTS-21 exerts a protective activity on not only impairment of learning and memory but also delayed neuronal death and that the underlying mechanism of GTS-21 differs from that of nicotine or THA.

Animals↗
PubMed1998

Stimulatory guanine nucleotide-binding protein in failing heart of hamsters and rats.

The role of the stimulatory guanine nucleotide-binding protein (Gs) in heart failure is unclear. We therefore determined the amount of protein and mRNA of Gs in the failing myocardium using two animal models: the BIO 53.58 hamster, a model of genetic cardiomyopathy, and adriamycin-treated rats (ADR rats), a model of secondary cardiomyopathy. The maximal number of myocardial beta-adrenoceptors in the BIO 53.58 hamsters as well as in the ADR rats was significantly lower than that in the respective controls, indicating that the beta-adrenoceptors were down-regulated in heart failure. Analysis by Western blot and Northern blot revealed a significant decrease in Gs protein and mRNA in the BIO 53.58 hamsters relative to the control. There were no differences in the level of Gs protein or mRNA in the ADR rats vs the controls. The functional activity of Gs was investigated by measuring adenylate cyclase activity. The activity of adenylate cyclase in response to stimulation by sodium fluoride or forskolin was decreased in the BIO 53.58 hamsters relative to control animals, whereas no differences were observed in the ADR rats vs the controls. Thus, alterations in Gs in the failing heart appear to differ according to its cause.

Adenylyl Cyclases↗
PubMed1998

A comparative study on the effects of nicotine and GTS-21, a new nicotinic agonist, on the locomotor activity and brain monoamine level.

Effects of GTS-21 [3-(2,4-dimethoxybenzylidene)-anabaseine dihydrochloride], a selective nicotinic agonist, on locomotor activity and dopamine turnover were examined and compared to those of nicotine to test if GTS-21 exhibits side effects similar to those of nicotine. GTS-21 had no effect on locomotor activity in mice or dopamine turnover in rats. In contrast, nicotine produced a biphasic effect on locomotor activity. It also enhanced dopamine turnover rates in the striatum and cerebral cortex, suggesting the involvement of dopaminergic systems in the nicotine-induced changes in locomotor activity. GTS-21 exhibits fewer adverse effects, suggesting that it has therapeutic potential for cognitive disorders related to central cholinergic dysfunction.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1998

[Long-term results after hepatectomy for hepatocellular carcinoma according to cancer stage].

The survival rates after hepatectomy for hepatocellular carcinoma (HCC) according to cancer stage were reported. The 5-year survival rates of Stage 1, 2, 3 and 4 were 69.6%, 54.2%, 35.9% and 30.2%, respectively. A significant difference was observed between any neighboring two stages. But more than 5 years till 20 years, the survival curves cross at some times. That means after 5 years the influence of the anatomic condition of the initial cancer has been weak. Probably another factor which controls multi-centric carcinogenesis of HCC may work. When the survival rate was calculated dividing the stage group into two sub-groups according to liver function, with good function or poor function, the survival of the poor liver function group of any stage group was worse than that of the good liver function group of the nearest worse stage group. The survival after hepatectomy of HCC depends not only upon anatomic condition of the cancer but also upon the liver function.

Carcinoma, Hepatocellular↗
PubMed1998

[Systematic resection for hepatocellular carcinoma].

We have performed systematic subsegmentectomy in patients with hepatocellular carcinoma complicated mainly by cirrhosis. Such small anatomical resections have become possible due to the introduction of intraoperative ultrasonography and of vascular occlusion techniques. As a result of our clinical experience involving 163 cases, it has been clarified that subsegmentectomy is a safe procedure (operative mortality rate, 0.6%) and results in a favorable long-term outcome (5-year survival rate, 51%). In the resected specimens, microscopic cancer spread was recognized frequently (portal venous invasion, 41%; intrahepatic metastasis, 31%). Subsegmentectomy is therefore the first procedure of choice in patients who have small hepatocellular carcinoma and chronic hepatitis or cirrhosis.

Aged↗
PubMed1998

A comprehensive typology for the biopsychosociocultural evaluation of child-killing behavior.

The homicide of children by their parents has been reported across numerous cultural settings around the world and in many historical periods. A comprehensive and systematic understanding of parental child killing can be optimally obtained through a biopsychosociocultural approach. In this article we present the case of a woman who committed neonaticide. We illustrate the cultural formulation of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) and recommend that this formulation has a central role in the evaluation of cultural factors of parents who kill their children.

Adolescent↗
PubMed1998

Renewing information infrastructure at Hospital das Clínicas.

In this paper we describe the process of renewing the Informatics infrastructure of Sao Paulo University Medical School Hospital, a very complex environment. Our proposal consists of a change in the paradigm of Informatics and the use of Information Technology in the hospital. That change aims at making information available to the hospital, its managers, health care workers and patients. The paradigm change is reflected in every aspect of the new infrastructure: human resources, methods, and organizational structure, as we intend to demonstrate in this paper. This process is expected to be concluded by the end of this year, yielding benefits regarding costs, efficiency, and better patient care.

Brazil↗