Biomedical subjects

A Sasaki

Publications and source records attributed to A Sasaki.

At least 109 records · Page 6Linked to original sources

PubMed2000

Laparoscopic cholecystectomy in the treatment of patients with gall bladder cancer.

BACKGROUND: Surgical procedures based on the depth of the primary tumor invasion (pT category) have been proposed in the treatment of gallbladder cancer (GBC). Trocar site metastases have been reported in patients who underwent laparoscopic cholecystectomy (LC) for preoperatively undiagnosed GBC. STUDY DESIGN: The aim of this study was to clarify the role of LC as a surgical strategy for GBC. From 1986 to 1998, 56 patients with GBC underwent surgical resection. Survival rates were compared retrospectively according to pT category and use of LC. RESULTS: Five-year survival was 91% for pT1 (n = 13), 64% for pT2 (n = 25), 34% for pT3 (n = 14), and 0% for pT4 tumors (n = 4; p<0.0001). LC was performed on 11 patients (4 with pT1, 5 with pT2, and 2 with pT3 tumors). Of the seven patients with pT2 or pT3 tumors, three underwent a second radical operation, three had an open radical operation to which the procedure was converted from LC, and one underwent no additional procedures. For pT1 tumors, one patient died of trocar site metastasis from bile spillage after LC. For pT2 or pT3 tumors, 5-year survival was 63% for radical surgery (n = 35) and 0% for cholecystectomy alone (n = 4; p<0.05). For pT2 or pT3 tumors treated by radical surgery, 5-year survival was 75% for laparoscopic approach (n = 6) and 60% for open surgery (n = 29; not significant). CONCLUSIONS: LC may help to establish the diagnosis and to determine the surgical strategy for undiagnosed GBC. It is important to prevent spillage or implantation of malignant cells during LC. For pT2 or pT3 tumors diagnosed laparoscopically, a second or converted open radical surgery is necessary.

Abdominal Neoplasms↗

PubMed2000

Effects of macrophage-colony-stimulating factor deficiency on the maturation of microglia and brain macrophages and on their expression of scavenger receptor.

Macrophage-colony-stimulating factor (M-CSF) regulates the survival, proliferation and differentiation of the mononuclear phagocyte lineage. Osteopetrotic (op/op) mice defective in producing functional M-CSF were used in order to investigate the role of M-CSF on the development of microglia and brain macrophages and the expression of scavenger receptor (SR). Adult op/op and littermate mice at 10-47 weeks of age were investigated by immunohistochemistry with a panel of monoclonal antibodies (F4/80, Mac-1, anti-major histocompatibility complex (MHC) class II and anti-SR), electron microscopy and reverse transcriptase-polymerase chain reaction (RT-PCR). Microglia were weakly immunolabeled with F4/80 and Mac-1 in op/op and littermate mice, but the number of microglia in op/op mice was reduced in the cerebrum, cerebellum and brainstem compared with that of normal littermates. The numbers of Mac-1-positive microglia in op/op mice was 39% (pons) and 30% (cerebellar cortex) lower than that in normal littermates (P<0.05). In addition, the microglia cell processes in op/op mice were often shorter than those in control mice. In op/op and littermate mice, both MHC class II and SR were present in perivascular cells and macrophages of the leptomeninx and choroid plexus. Ultrastructurally, perivascular cells appeared to be immature, since their cytoplasm was narrow and contained few inclusion bodies compared with those of control mice. Reverse transcriptase-polymerase chain reaction showed a weak expression for SR mRNA in the brains of op/op mice as well as littermate mice. These results indicate that microglia are partly dependent on M-CSF for their proliferation and differentiation and that M-CSF has no significant effect on the expression of SR in the physiological brain. The study also suggests that M-CSF affects the maturation of perivascular cells at the ultrastructural level.

Animals↗

PubMed2000

Correlation of thrombospondin-1 and transforming growth factor-beta expression with malignancy of glioma.

The expression of thrombospondin-1 (TSP-1) and its role in gliomas have not been well examined. In the present study TSP-1 expression in a panel of malignant glioma cell lines and the expression of TSP-1 and transforming growth factor (TGF-beta) proteins in low-grade and malignant glioma tissues were investigated. Reverse transcription-polymerase chain reaction analysis showed that nine of nine malignant glioma cell lines expressed TSP-1 mRNA, and seven of nine glioma lines expressed TSP-2 mRNA. Production and secretion of TSP-1 were examined in the T98G glioblastoma cell line by western blot analysis. Total TSP-1 protein content in the supernatant was 10 times higher than that in the cell lysate. Secretion of TSP-1 was examined in these glioma cell lines by western blot analysis. All glioma lines secreted significant levels of TSP-1. Bioassay showed that all tumor lines had the capacity to activate latent TGF-beta. Localization of TSP-1, TGF-beta1, -beta2, and -beta3 was examined immunohistochemically in surgically resected glioma tissues, including 11 glioblastomas, six anaplastic astrocytomas, and eight astrocytomas. Most glioblastomas expressed high levels of both TSP-1 and TGF-beta. Anaplastic astrocytomas expressed moderate levels of TSP-1 and TGF-beta. Most malignant gliomas expressed various levels of TGF-beta1, -beta2, and -beta3. The expression of both proteins, however, was weak in low-grade gliomas. Normal brain tissues around the tumors were negatively or very weakly positively stained for TSP-1 and TGF-beta. These results indicate that most malignant glioma cells express TSP-1 in vitro and in vivo, and the expression of TSP-1 and TGF-beta in vivo correlates with the histologic malignancy of glioma. Overexpression of both TSP-1 and TGF-beta may increase the biologic malignancy of malignant gliomas, through generating the active form of TGF-beta in tumor tissues.

Astrocytoma↗

PubMed2000

A novel monoclonal antibody that recognizes human perivascular cells of the central nervous system under a specific immune reaction.

Perivascular cells or fluorescent granular perithelial cells of the central nervous system are newly recognized members of monocyte/macrophage populations. In this study a monoclonal antibody, GP-3, that labels proteinous lysosomal antigen of human perivascular cells, has been established. It selectively label the cells in foamy-macrophage infiltrating diseased areas, such as Wallerian degeneration and contusion, without significant reaction to the cells in normal areas, infiltrating macrophages or microglia. These findings suggest that the perivascular cell is an independent cell type and the antigen molecule is fairly specific to perivascular cells and plays an unknown role in immune-nervous system interaction.

Adult↗

PubMed2000

Cerebellar basket cells of Creutzfeldt-Jakob disease: immunohistochemical and ultrastructural study.

To elucidate possible abnormalities of cerebellar basket cells of Creutzfeldt-Jakob disease (CJD), seven sporadic cases were examined neuropathologically. Recently, parvalbumin-positive, GABAergic cerebral interneurons have been demonstrated to show early, selective loss in CJD, and the phenomenon is postulated as a cause of characteristic neurological symptoms of CJD. In this study, however, we demonstrated that the basket cells, cerebellar counterparts, were resistant even in patients with severe brain atrophy, and their processes showed intense argyrophilia and immunopositivity to phosphorylated neurofilament. They can newly be listed as CJD-resistant neurons similar to those of the hippocampus and brainstem nuclei. The mechanism to escape cell loss is of great interest, and there might be unknown factors modulating susceptibility within parvalbumin-positive neuronal subgroups. Furthermore, one case showed abnormal positivity with hematoxylin, crystal violet and pyronin in the basket cells. The pyronin positivity was reduced after ribonuclease digestion, suggesting that the causative substance was composed of RNA. Ultrastructurally, the fibers contained free ribosomes and amorphous electron-dense deposits. To our knowledge, such a finding has also not been previously reported.

Aged↗

PubMed2000

EUS in cirrhotic patients with and without prior variceal hemorrhage in comparison with noncirrhotic control subjects.

BACKGROUND: Endoscopic ultrasound (EUS) was used to evaluate cirrhotic patients with and without prior variceal hemorrhage. The findings were compared with those of EUS in noncirrhotic control subjects to determine EUS features indicative of cirrhosis and of a risk for variceal hemorrhage. METHODS: Patients with cirrhosis undergoing indicated endoscopic screening for varices or surveillance after endoscopic therapy for variceal hemorrhage were studied and compared with healthy noncirrhotic control patients undergoing EUS for benign conditions. RESULTS: Sixty-six cirrhotic patients (31 with prior hemorrhage) and 32 control patients were studied. Nonhemorrhage cirrhotic patients had more severe liver disease by Child's class (p = 0.02) and less beta-adrenergic blocker usage (p < 0.0001). Paraesophageal varices were detected in 97% of cirrhotic patients and 3% of control patients (p < 0.001) and were a more sensitive predictor of cirrhosis than varices at endoscopy (74%, p < 0.0001). Azygos vein and thoracic duct diameters, and gastric mucosa and submucosa thickness were greater for cirrhotic than control patients (p < 0.001). More hemorrhage patients had large (5 mm or greater) paraesophageal varices (odds ratio 3.1: 95% CI [1.1, 8.3]; p < 0.05) and paragastric varices (odds ratio 3.7: 95% CI [1.3, 10.2]; p = 0.01). Paraesophageal varix size correlated with ascites (p = 0.03) and, for nonhemorrhage patients, with Child's class (p < 0.01). CONCLUSIONS: Paraesophageal and paragastric varices correlate with the presence and severity of liver disease and portal hypertension. These data support the hypothesis that large paraesophageal and paragastric varices (5 mm or greater) may be risk factors for variceal hemorrhage, an observation that merits further prospective study. Cirrhosis causes dilation of the azygos vein and thoracic duct and thickening of gastric mucosa and submucosa.

Azygos Vein↗

PubMed2000

Soft tissue cephalometric norms in Japanese adults.

Lateral soft tissue cephalometric standards of Japanese normal adults were developed with the use of Ricketts, Epker, Holdaway, and Legan cephalometric analyses. Cephalometric radiographs of 211 Japanese normal adults were analyzed, and the soft tissue measurements were compared with those of an esthetically pleasant Japanese subgroup and white adult sample. Statistically significant differences were found in the Japanese sample when compared with the white norms. On the other hand, the soft tissue mean values of the Japanese supernormal group were similar to the white norms, with the exception of the nasolabial angle and the lip prominence. Soft tissue cephalometric norms are specific for ethnic groups, but these values should not be interpreted as treatment goals. Normative data represent an aid for the diagnosis and planning of orthodontic treatment and orthognathic surgery.

Adult↗

PubMed2000

An adult case of TMJ osteoarthrosis treated with splint therapy and the subsequent orthodontic occlusal reconstruction: adaptive change of the condyle during the treatment.

This article reports treatment for a 21-year 11-month old female patient with severe osteoarthrosis of the TMJ with a special reference to adaptive changes of the condyle during the treatment. She had severe open bite with a Class II molar relationship; she had limited mouth opening, TMJ sounds, pain, and tinnitus. Lateral tomograms showed flattening and deep erosion on the left condyle, and an MRI revealed anterior disk displacement without reduction. By manipulation and splint therapy, TMJ pain and tinnitus were eliminated, then orthodontic treatment was initiated, maintaining the splint-induced position of the condyles. After 2 years of orthodontic treatment with a multibracket appliance, an acceptable occlusion was achieved with a Class I molar relationship. On lateral tomograms after treatment, bony deformation of the left condyle disappeared and adaptive remodeling was recognized with a uniform joint space in the left TMJ. However, repositioning of the disk was not achieved. Adaptive changes or functional remodeling experienced in this patient may be due to stable occlusion, uniform joint space, and the consequent biomechanical equilibrium in the TMJ.

Adaptation, Physiological↗

PubMed2000

Prepulse effects on the interaction of intense femtosecond laser pulses with high-Z solids

Kalpha emission of high-Z solid targets irradiated by an intense, short (<100 fs) laser pulse in the 10 keV region is shown to be sensitive to the electron energy cutoff, which is strongly dependent on the density gradient of the plasma corona formed by a long prepulse. The absorption rate of short laser pulses, the hot electron distribution, and x-ray emission from a Cu slab target are studied via a hybrid model, which combines the hydrodynamics, collisional particle-in-cell, and Monte Carlo simulation techniques, and via a direct spectroscopic measurement. An absorption mechanism originating from the interaction of the laser pulse with plasma waves is found to increase the absorption rate by over 30% even for a very short, s-polarized laser pulse. Calculated and measured x-ray spectra are in good agreement, confirming the electron energy cutoff.

Journal Article↗

PubMed2000

Characterization of Staphylococcus aureus coagulase type VII isolates from staphylococcal food poisoning outbreaks (1980-1995) in Tokyo, Japan, by pulsed-field gel electrophoresis.

Staphylococcus aureus coagulase type VII strains have been the strains most frequently isolated from staphylococcal food poisoning outbreaks in Tokyo, Japan. We applied pulsed-field gel electrophoresis (PFGE) of chromosomal DNA digested with SmaI to characterize 129 coagulase type VII strains. These were isolated from 129 cases occurring in outbreaks in 35 districts during a 16-year period (1980-1995). The 129 outbreak strains were classified into three types, designated A (n = 115), B (n = 10), and C (n = 4). Types A and C were further divided into 33 (A1 to A33) and 4 (C1 to C4) subtypes, respectively. Strains of the same subtypes were isolated from food poisoning cases in the same districts at time intervals of 1 or 2 to 5 years. PFGE typing appears to be a useful method for subdividing strains of S. aureus coagulase type VII. A combination of coagulase typing and PFGE typing would provide more detailed information than the former method alone in epidemiologic investigations of staphylococcal food poisoning.

Bacterial Typing Techniques↗

PubMed2000

Accumulation of NACP/alpha-synuclein in lewy body disease and multiple system atrophy.

OBJECTIVES: NACP/alpha-synuclein is an aetiological gene product in familial Parkinson's disease. To clarify the pathological role of NACP/alpha-synuclein in sporadic Parkinson's disease and other related disorders including diffuse Lewy body disease (DLBD) and multiple system atrophy (MSA), paraffin sections were examined immunocytochemically using anti-NACP/alpha-synuclein antibodies. METHODS: A total of 58 necropsied brains, from seven patients with Parkinson's disease, five with DLBD, six with MSA, 12 with Alzheimer's disease, one with Down's syndrome, one with amyotrophic lateral sclerosis (ALS), three with ALS and dementia, one with Huntington's disease, two with progressive supranuclear palsy (PSP), one with Pick's disease, one with myotonic dystrophy, and three with late cerebellar cortical atrophy (LCCA), and 15 elderly normal controls were examined. RESULTS: In addition to immunoreactive Lewy bodies, widespread accumulation of NACP/alpha-synuclein was found in neurons and astrocytes from the brainstem and basal ganglia to the cerebral cortices in Parkinson's disease/DLBD. NACP/alpha-synuclein accumulates in oligodendrocytes from the spinal cord, the brain stem to the cerebellar white matter, and inferior olivary neurons in MSA. These widespread accumulations were not seen in other types of dementia or spinocerebellar ataxia. CONCLUSION: Completely different types of NACP/alpha-synuclein accumulation in Parkinson's disease/DLBD and MSA suggest that accumulation is a major step in the pathological cascade of both diseases and provides novel strategies for the development of therapies.

Aged↗

PubMed2000

Negative regulation of cytokine signaling pathways.

The Janus family of protein tyrosine kinases (JAKs) and STAT transcription factors regulate cellular processes involved in cell growth, differentiation, and transformation through their association with cytokine receptors. The CIS family of proteins (also referred to as the SOCS or SSI family) has been implicated in the regulation of signal transduction by a variety of cytokines. Most of them appear to be induced after stimulation with several different cytokines, and at least three of them (CIS1, CIS3/SOCS3, and JAB/SOCS1) negatively regulate cytokine signal transduction by various means: CIS1 inhibits STAT5 activation by binding to cytokine receptors that recruit STAT5, whereas JAB/SOCS-1 and CIS3/SOCS-3 directly bind to the kinase domain of JAKs, thereby inhibiting tyrosine-kinase activity. Therefore, these CIS family members seem to function in a classical negative feedback loop of cytokine signaling. Biochemical characterization as well as gene disruption studies indicate that JAB/SOCS1/SSI-1 is an important negative regulator of interferon gamma signaling. The mechanisms by which these inhibitors of cytokine signal transduction exert their effects have been extensively studied and will provide useful information for regulating tyrosine-kinase activity.

Animals↗

PubMed2000

[One advice to the decision of graft size for ascending and total arch graft replacement (in a case of differential diameters in ascending aorta and descending aorta)].

We carried out the surgery of thoracic aortic aneurysm in fifty-eight patients from June 1994 to February 1999 (including aortic dissection in twenty-six patients). The mean size of grafts were 28.1 mm in ascending graft replacement, 25.8 mm in both ascending and arch graft replacement and 23.8 mm in descending graft replacement. The grafts for ascending aortic aneurysm were significantly larger than those for descending aortic aneurysm. In two of twenty-six patients undergoing both ascending and arch graft replacement, different size of grafts were used for ascending replacement and for arch replacement with satisfactory results in terms of bleeding from the anastomotic sites. Case 1; A 45-year-female with aortitis syndrome and aortic regurgitation due to annuloaorticectasia and thoracic aortic aneurysm underwent simultaneous aortic root replacement with composite graft (25 mm St. Jude Medical valve and 28 mm Hemashield graft) and total arch replacement (30 mm Hemashield graft with two side branches). Case 2; A 64-year-female was diagnosed as chronic type II dissecting aneurysm combined with acute type I aortic dissection. Ascending aorta was replaced with a 26 mm Hemashield graft, and the aortic arch was replaced with a 24 mm Hemashield graft with three side branches.

Anastomosis, Surgical↗

PubMed2000

[A successful repair of intraoperative retrograde type A aortic dissection in a patient with aortic regurgitation and ascending aortic aneurysm].

The patient was a 67-year-old male with aortic regurgitation and ascending aortic aneurysm. We noticed the type A retrograde aortic dissection occurring from the cannulation site through the right femoral artery. We discontinued cardio-pulmonary bypass immediately, and established selective cerebral perfusion (SCP) eleven minutes after retrograde cerebral perfusion (RCP). We underwent simultaneous aortic valve replacement and ascending and arch graft replacement with an aid of SCP combined with RCP and systemic low flow perfusion. Postoperative course was satisfactory, although patient had a transient neurologic deficit. Intraoperative aortic dissection is a rare but potentially fatal complication. RCP may be a simple and useful method in emergency operation for intraoperative retrograde type A aortic dissection to avoid serious cerebral damage.

Aged↗

PubMed2000

[A case of mediastinal non seminomatous germ cell tumor successfully treated with chemotherapy and curative surgery].

A 15-year-old male was admitted to our hospital because of left lateral chest pain. Chest XP and CT scan revealed a huge anterior mediastinal mass (13 x 8 x 12 cm). The serum AFP level was raised (8,089 ng/ml). Examination of a percutaneous biopsy of the tumor suggested non-seminomatous germ cell carcinoma. After three courses of chemotherapy with CDDP, Bleomycin and VP-16, the mass reduced in size and the serum AFP level decreased to the normal range. The tumor was completely removed. The postoperative course was uneventful and he has had no recurrence for 10 months following the operation. AFP is a very useful parameter for deciding the timing for an operation.

Adolescent↗

PubMed2000

[Ruptured aneurysm of sinus of Valsalva into the right atrium with aortic valve perforation].

A 58-year-old female was admitted to our hospital because of sudden dyspnea and general malaise. A continuous murmur was heard along the left sternal border. A chest X-ray showed cardiomegaly and pulmonary vascular marking. Doppler echocardiography confirmed the presence of an aneurysmatic mass, originating from the non-coronary sinus of Valsalva and extending to the right atrium, with a turbulent flow into the right atrium, aortic regurgitation (II/IV) and tricuspid regurgitation (III/IV). Ascending aortography demonstrated a communication between the aortic sinus and the right atrium. The pulmonary-to-systemic flow ratio was calculated to be 2.04. Oblique aortotomy and right atriotomy were performed. The aneurysm was resected and its origin was directly closed with horizontal mattress sutures through the aortic side and right atrial side. Perforation of a non-coronary cusp that caused aortic regurgitation was found following aortotomy and it was closed with an autologous pericardial patch. Tricuspid annuloplasty was performed using DeVega's technique. The postoperative course was uneventful, and she was discharged on the 10th postoperative day.

Aortic Rupture↗

PubMed1999

Detection of silent myocardial ischemia patients by the spatial velocity electrocardiogram.

This study was designed to detect patients with type I silent myocardial ischemia (SMI) at rest by assessing the symmetry of the electrocardiographic (ECG) T wave using the spatial velocity electrocardiogram (SVECG). In this study, the ECG T waves in patients with SMI were symmetric compared with those in normal subjects, and the the c/a ratio in the SVECG-T wave as the index of degree of symmetry of the ECG T wave enabled us to diagnose 73% of these patients; the c/a ratio in the SVECG T wave was a useful index for detecting patients with type I SMI at rest.

Aged↗

PubMed1999

CIS associates with the interleukin-2 receptor beta chain and inhibits interleukin-2-dependent signaling.

CIS is a cytokine-induced SH2-containing protein that was originally cloned as an interleukin (IL)-3-inducible gene. CIS is known to associate with the IL-3 receptor beta chain and erythropoietin receptor and to inhibit signaling mediated by IL-3 and erythropoietin. We now demonstrate that CIS also interacts with the IL-2 receptor beta chain (IL-2Rbeta). This interaction requires the A region of IL-2Rbeta (residues 313-382), which also mediates the association of IL-2Rbeta with Lck and Jak3. Correspondingly, CIS inhibits functions associated with both of these kinases: Lck-mediated phosphorylation of IL-2Rbeta and IL-2-mediated activation of Stat5. Thus, we demonstrate that CIS can negatively control at least two independent IL-2 signaling pathways. Although a functional SH2 binding domain of CIS was not required for its interaction with IL-2Rbeta in vitro, its phosphotyrosine binding capability was essential for the inhibitory action of CIS. On this basis, we have generated a mutant form of CIS protein with an altered SH2 domain that acts as a dominant negative and should prove useful in further understanding CIS action.

Amino Acid Sequence↗