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Biomedical subjects

H Sakata

Publications and source records attributed to H Sakata.

At least 19 recordsLinked to original sources
PubMed1999

Ileal varices associated with recurrent bleeding in a patient with liver cirrhosis.

We report a rare case of massive and recurrent bleeding from ileal varices in a patient with hepatitis C virus-positive liver cirrhosis. A 66-year old woman, who had undergone laparotomy and blood transfusion 36 years before (because of an extrauterine pregnancy) and endoscopic sclerotherapy for esophageal varices 1 year previously, was admitted to our hospital with loss of bright red blood per rectum. The bleeding was massive and recurrent, and frequent blood transfusions were required. Endoscopic studies failed to find the bleeding site. In the venous phase of selective superior mesenteric angiography, mesenteric varices in the lower part of the abdominal cavity were observed. Laparotomy was performed to control the repeated bleeding which had lasted for more than 1 month. Varices communicating with the right ovarian vein were found on the ileal wall and segmental resection of the ileum was performed. Histological examination demonstrated a massive varicose vein and several dilated veins in the submucosa. The patient's postoperative course was favorable, with no hemorrhagic events during a follow-up of more than 6 months after surgery. Ileal varices should be considered in the diagnosis of a patient who presents with lower gastrointestinal bleeding and portal hypertension.

Aged↗
PubMed1999

Evaluation of endoscopic variceal ligation in prophylactic therapy for bleeding of oesophageal varices: a prospective, controlled trial compared with endoscopic injection sclerotherapy.

BACKGROUND: To evaluate the efficacy of endoscopic variceal ligation (EVL) in prophylactic therapy for oesophageal varices, we performed a randomized prospective trial to compare the recurrence of oesophageal varices treated by EVL with those treated by endoscopic injection sclerotherapy. METHODS: Fifty patients with liver cirrhosis were divided into two groups at random, after informed consents were obtained, to receive prophylactic therapy for bleeding of oesophageal varices. Group 1 patients underwent sessions of sclerotherapy with 5% ethanolamine oleate used as the sclerosant. Group 2 patients underwent EVL followed by one or two sessions of sclerotherapy. RESULTS: During the 18 month follow-up period, both the recurrence rate in group 2 (56%) and the incidence of bleeding (20%) were significantly higher compared with group 1 (recurrence rate 16%, bleeding 0%). CONCLUSIONS: This result indicates that EVL is not effective for prophylactic therapy for oesophageal varices in liver cirrhosis.

Esophageal and Gastric Varices↗
PubMed1998

Neural coding of 3D features of objects for hand action in the parietal cortex of the monkey.

In our previous studies of hand manipulation task-related neurons, we found many neurons of the parietal association cortex which responded to the sight of three-dimensional (3D) objects. Most of the task-related neurons in the AIP area (the lateral bank of the anterior intraparietal sulcus) were visually responsive and half of them responded to objects for manipulation. Most of these neurons were selective for the 3D features of the objects. More recently, we have found binocular visual neurons in the lateral bank of the caudal intraparietal sulcus (c-IPS area) that preferentially respond to a luminous bar or place at a particular orientation in space. We studied the responses of axis-orientation selective (AOS) neurons and surface-orientation selective (SOS) neurons in this area with stimuli presented on a 3D computer graphics display. The AOS neurons showed a stronger response to elongated stimuli and showed tuning to the orientation of the longitudinal axis. Many of them preferred a tilted stimulus in depth and appeared to be sensitive to orientation disparity and/or width disparity. The SOS neurons showed a stronger response to a flat than to an elongated stimulus and showed tuning to the 3D orientation of the surface. Their responses increased with the width or length of the stimulus. A considerable number of SOS neurons responded to a square in a random dot stereogram and were tuned to orientation in depth, suggesting their sensitivity to the gradient of disparity. We also found several SOS neurons that responded to a square with tilted or slanted contours, suggesting their sensitivity to orientation disparity and/or width disparity. Area c-IPS is likely to send visual signals of the 3D features of an object to area AIP for the visual guidance of hand actions.

Animals↗
PubMed1998

Fatty acid omega and (omega-1)-oxidation within intrasplenically transplanted fetal hepatocytes.

BACKGROUND: The expression and enzymatic activity of the cytochrome P450 LAomega within intrasplenically transplanted hepatocytes was investigated. METHODS: Fetal hepatocytes were harvested from spontaneously hypertensive rats and transplanted into recipient adult spontaneously hypertensive rat spleens. RESULTS: Microscopic examination revealed masses of hepatocytes in the red pulp. Immunochemical studies detected cytochrome P450 LAomega in transplanted hepatocytes by 6 and 10 weeks after transplantation. Cytochrome P450 LAomega mRNA accumulates at 6 weeks after transplantation. Cytochrome P450-arachidonic acid omega/omega-1 hydroxylase activity (formation of 20/19-hydroxyeicosatetraenoic acid) was detected at 10 weeks after transplantation. CONCLUSION: These results demonstrated that fetal hepatocytes grow in the spleen and function similarly to adult hepatocytes.

Animals↗
PubMed1998

Infected abdominal aortic aneurysm caused by Campylobacter fetus subspecies fetus: report of a case.

A 45-year old man with fever, abdominal pain, and a pulsating mass underwent an aneurysmectomy, with in situ reconstruction using a bifurcated knitted Dacron graft, for a saccular abdominal aortic aneurysm (AAA). A culture taken postoperatively grew Campylobacter fetus subspecies fetus. The administration of antibiotics sensitive to this organism was continued for 3 months, and no infection has been encountered in the 1 year since his operation. This is only the 13th documented case of AAA infected by C. fetus subspecies fetus.

Aneurysm, Infected↗
PubMed1998

Outbreak of severe infection due to adenovirus type 7 in a paediatric ward in Japan.

Between November 1996 and January 1997, 14 patients were diagnosed as having infection caused by adenovirus type 7 in a paediatric ward of Asahikawa Kosei Hospital. The age range of the patients was from two months to five years. Their diseases and abnormal laboratory findings were pneumonia in all 14, leukocytopenia in 10, myositis in nine, gastroenteritis in eight, encephalitis in five, liver dysfunction in three, pleuritis in two, inappropriate secretion of antidiuretic hormone syndrome in two, and thrombocytopenia in two. The infected patients, except for the first had been hospitalized in the paediatric ward for treatment of another disease and re-admitted because of high fever and coughing a few days after improvement or discharge. It is thought that the cause of the outbreak was hospital-acquired infection.

Adenovirus Infections, Human↗
PubMed1998

Fifteen-year experience in axillofemoral bypass with externally supported knitted Dacron prosthesis in a Japanese hospital.

BACKGROUND: Recently, several reports in the United States have demonstrated remarkable improvement in the patency of axillofemoral (AXF) bypass with an externally supported prosthesis. The purpose of this study was to review the prognoses regarding graft patency, limb salvage, and survival of patients who underwent AXF bypass grafting with an externally supported, knitted Dacron prosthesis (EXS) in a Japanese hospital and to analyze what factors affected the graft patency. METHODS: The clinical records of 81 patients with arteriosclerosis obliterans (ASO) who underwent 47 axillounifemoral bypasses and 34 axillobifemoral bypasses with EXS were retrospectively checked and, by uni- and multivariate analysis, perioperative factors were evaluated. RESULTS: The cumulative primary and secondary patency rates of AXF bypass grafts were 81% and 88%, 73% and 80%, and 70% and 77% at 3, 5, and 7 years, respectively, with no change thereafter. Limb salvage rate was 100%. The operative mortality was 3.7% and the survival rate was 63%, 41%, and 35% at 3, 5, and 7 years, respectively. The risk factors adversely affecting the patency were age (younger than 75 years), poor distal runoff, and preoperative leukocyte count (more than 8,000/microL) by univariate analysis, none of which were significant by stepwise multivariate analysis. CONCLUSIONS: AXF bypass using EXS was an acceptable procedure in ASO patients at high risk for conventional anatomic bypass or with limited life expectancy, and there was no significant risk factor that independently affected the patency.

Age Factors↗
PubMed1998

Changes in purine metabolism and production of oxygen free radicals by intermittent partial umbilical cord occlusion in chronically instrumented fetal lambs.

OBJECTIVE: Undetected umbilical-cord compression has been suggested to be implicated in unexplained fetal brain damage. We tested the hypothesis that the generation of oxygen-free radicals (OFRs) during intermittent partial umbilical cord occlusion might play a causal role in antenatal CNS injury. METHODS: Using 7 established chronically instrumented fetal lambs, intermittent partial occlusion of the umbilical circulation was produced according to the method of Clapp et al. for 1 of every 3 minutes for 2 hours. A microdialysis probe was implanted in the fetal brain white matter. Normal saline was infused, and the perfusate obtained at 2 micrograms/ min. Hypoxanthine (HX), xanthine (XA), and inosine-5-monophosphate (IMP) concentrations in the perfusate and blood samples obtained from fetal jugular veins were assayed by HPLC. Concurrently, the perfusate, which contained superoxide produced in the brain, when mixed with cypridina luciferin analogue extracorporally, caused chemiluminescence that in 4 cases was measured by a highly sensitive electronic fluorescence detector. RESULTS: (1) HX, XA, and IMP concentrations in the blood and perfusate were higher than in the control during the intermittent partial occlusion of the umbilical circulation period and returned to control levels during the recovery period. (2) The residual chemiluminescence of perfusate revealed that the intermittent partial occlusion of the umbilical circulation level was about 100% higher than the control level, and during the recovery period the level returned to the control level. (3) The chemiluminescence during the intermittent partial occlusion of the umbilical circulation period was inhibited by infusion through the fetal jugular vein of 1 micron polyethylene glycol conjugated superoxide dismutase. CONCLUSION: During the intermittent partial occlusion of the umbilical circulation period the fetal brain tissue releases a large amount of OFRs, and a portion of these might be synthesized by the increased conversion of HX to XA. This phenomenon might play an important role in the etiology of fetal brain injury.

Animals↗
PubMed1998

[Result of antibiotic therapy for children with Escherichia coli O26:H11 infection].

Between the end of November 1996 and the beginning of March 1997, there was an outbreak of Escherichia coli O26:H11 infection in Asahikawa. The strain produced only verotoxin type 1. The minimal inhibitory concentrations (microgram/ml) of the strain under aerobic condition and those of anaerobic were as follows: chloramphenicol (1.56, 0.78), minocycline (12.5, 3.13), kanamycin (3.13, 25), ampicillin (> 100, > 100), fosfomycin (12.5, 1.56), norfloxacin (0.1, 0.1), and cefaclor (6.25, 3.13). Forty-one episodes of antibiotic therapy to 32 children, who were treated in Asahikawa Kosei Hospital, Asahikawa Municipal Hospital, and Asahikawa Red Cross Hospital, were evaluated bacteriologically. In 26 episodes treated with fosfomycin, the pathogen from stools of 19 were eradicated, 4 were not eradicated, and 3 were isolated again within 2 weeks after the cessation of therapy. Eight episodes treated with norfloxacin and 5 episodes in kanamycin were all eradicated.

Anti-Bacterial Agents↗
PubMed1998

[Study on bacteremia due to community-acquired infection in infants and children without underlying diseases].

Between July 1988 and June 1998, 22 pediatric patients without underlying diseases were diagnosed as bacteremia caused by community-acquired infection in Asahikawa Kosei Hospital. The age range of the patients was from 7 days to 4 years. Their diseases were meningitis in 6, urinary tract infection in 6, respiratory tract infection in 4, skin infection in 2, and unknown origin in 4. The causative organisms were Escherichia coli in 7, Haemophilus influenzae in 4, Streptococcus pneumoniae in 4, Staphylococcus aureus in 2, Streptococcus pyogenes in 1, Streptococcus agalactiae in 1, Listeria monocytogenes in 1, Moraxella catarrhalis in 1, and Rahnella aquatilis in 1. Though 21 patients recovered with antimicrobial treatment, only one patient with H. influenzae meningitis had lateral deafness and paresis in the lower limbs as sequelae.

Bacteremia↗
PubMed1998

[Serratia marcescens brain abscess in a newborn].

The patient was born by emergency cesarean section for fetal distress at 35 weeks gestation with a weight of 2740 g. The early neonatal course was complicated by transient tachypnea and renal failure. He was receiving oxygen and diureticus in incubator for 5 days and his condition was very improved on day 5. On day 7 he became lethargy and there was inability to tolerate feeding. Investigation of the cerebrospinal fluid revealed 8,000 leukocytes/microliter. S. marcescens was grown from cultures of both blood and cerebrospinal fluid. Treatment was started with cefotaxime and ampicillin every 6 hour. On day 14 the CT showed a brain abscess located parietooccipitally on the left side and diffuse infarction on the right side. On day 14 and 23 recurrence of increased leukocytes in the cerebrospinal fluid, high values of serum CRP and deterioration of clinical symptoms were observed. It is thought that the episodes show rupture of the abscess into the lateral ventricle. On day 55 surgical drainage was performed for the hydrocephalus. On day 110 the abscess was not found in the brain CT scan. His psychomotor development 3 years later was equivalent to two years old and he had secondary epilepsy.

Brain Abscess↗
PubMed1998

Measles virus attenuation associated with transcriptional impediment and a few amino acid changes in the polymerase and accessory proteins.

Measles virus (MV) isolated in B95a cells, a marmoset B-cell line, retains full pathogenicity for cynomolgus monkeys, while its derivative obtained by adaptation to the growth in Vero cells, a monkey kidney cell line, loses the pathogenic potential (F. Kobune, H. Sakata, and A. Sugiura, J. Virol. 64:700-705, 1990). Here, we show with a pair of strains, a fresh isolate (9301B) in B95a cells and its Vero cell-adapted form (9301V), that the in vivo attenuation parallels the decrease of replication and syncytium-inducing capabilities in the original B95a cells and that these in vitro phenotypes are attributable to impediment of transcription, which is already obvious at the level of primary transcription catalyzed by the virion-associated RNA polymerase. On the other hand, cell fusion assays detected no functional difference between the glycoproteins of the two viruses. Essentially the same transcriptional impediment with reduced syncytium induction following Vero cell adaptation was found with two other pairs of strains that had been similarly prepared. Nucleotide sequence comparison between the 9301B and 9301V viruses revealed that a few (at most five) amino acid changes, which sporadically took place in the polymerase (L and P proteins) and/or accessory V and C proteins, were responsible for the in vitro and in vivo attenuation through adaptation to growth in Vero cells.

Adaptation, Physiological↗
PubMed1998

LDL apheresis for arteriosclerosis obliterans with occluded bypass graft: change in prostacyclin and effect on ischemic symptoms.

To study the mechanism of efficacy of low-density lipoprotein (LDL) adsorption for arteriosclerosis obliterans (ASO), eight ASO patients without indication for bypass surgery underwent LDL apheresis twice a week for 5 weeks and the change in prostaglandin 12 (PGI2) and thromboxane A2 (TXA2) due to LDL apheresis was measured. The concentration of 6-keto-PGF1alpha, a metabolite of PGI2, in systemic venous blood significantly increased from 10.4 +/- 1.8 to 42.0 +/- 10.6 pg/mL (P<0.05) after one session of LDL apheresis, while no significant change of TXB2, a metabolite of TXA2, was encountered. The ratio of 6-keto-PGF1alpha/TXB2 also rose dramatically from 0.213 +/- 0.044 to 0.522 +/- 0.128 (P<0.05). In five patients, the ischemic clinical symptoms improved and both the concentration of 6-keto-PGF1alpha and the ratio of 6-keto-PGF1alpha/TXB2 increased significantly, whereas in three patients there was no effect on clinical symptoms and neither parameter changed. These results suggest that elevated production of PGI2 from vascular cells due to LDL apheresis might contribute to improvement of ischemic symptoms.

Aged↗
PubMed1998

A wild-type Japanese measles virus strain inducing predominant early down-regulation of CD46.

Down-regulation of CD46 secondary to stimulation with measles virus (MV) was investigated using CD46-positive cell lines and Japanese wild-type MV strains. The cells used were simian cell lines B95a and Vero in which MV strains have been adapted to be amplified, and Chinese hamster ovary (CHO) cell transfectants expressing human CD46 with (CHO(tail+)) or without (CHO(tail-)) the cytoplasmic tail. Of four Vero-adapted and three B95a-adapted MV strains, one Vero-adapted strain named Khono (KO), down-regulated CD46 within 60 min (early down-regulation) in all cell lines examined except Vero. No strains other than Toyoshima (TY), which induced early down-regulation only in CHO(tail+) cells, induced early down-regulation of CD46 in any combination. On the other hand, conventional down-regulation of CD46 was observed 24 h post-MV inoculation (late down-regulation) when cell lines used were adapted to MV strains. Thus, we concluded that there are two modes of CD46 down-regulation by MV and the unique strain KO markedly induces early down-regulation. Also, the CD46 homologue of B95a, which fails to act as a MV receptor, is down-regulated concomitantly with MV replication (>24 h) in cells principally by competent virus strains.

Amino Acid Sequence↗
PubMed1998

Para-anastomotic aneurysms: incidence, risk factors, treatment and prognosis.

BACKGROUND: The purpose of this retrospective study was to analyze the incidence, risk factors, treatment, and prognosis of para-anastomotic aneurysms. METHODS: During the period between January, 1980 and August, 1996, 511 patients underwent surgical operations for arterial diseases with grafts and were followed for more than 30 days (average: 3.5 years). The number of anastomoses was 1445 in all. Until October, 1996, 18 para-anastomotic aneurysms had been detected in 13 patients. By Kaplan-Meier's method, the incidence of para-anastomotic aneurysms at 5, 10, and 15 years was 0.8, 6.2, and 35.8%, respectively. Univariate analysis indicated that arteriosclerosis obliterans, hypertension, thromboendarterectomy and an anastomosis in the groin were significant risk factors, while stepwised multivariate analysis revealed only hypertension as significant. The mean interval from the primary operation to the diagnosis was 79 months. Ten aneurysms were operated and seven were produced by dehiscence of the anastomotic line, namety anastomotic aneurysms, and three were juxta-anastomotic aneurysms with intact anastomotic lines. Eight patients underwent resection or exclusion of the aneurysm and reconstruction with a new graft and two patients underwent a replacement of the aneurysmal autovein patch to a Dacron one and aneurysmorrhaphy of the parent aneurysmal artery. RESULTS: No recurrence has been detected. In eight patients who were followed conservatively, two died of rupture and renal failure following acute arterial occlusion. CONCLUSIONS: Since para-anastomotic aneurysms can lead to fatal complications, an enlarging or symptomatic aneurysm should be treated promptly.

Adult↗
PubMed1997

Functional and biophysical characterization of recombinant human hepatocyte growth factor isoforms produced in Escherichia coli.

Hepatocyte growth factor (HGF) is a pluripotent secreted protein that stimulates a wide array of cellular targets, including hepatocytes and other epithelial cells, melanocytes, endothelial and haematopoietic cells. Multiple mRNA species transcribed from a single HGF gene encode at least three distinct proteins: the full-length HGF protein and two truncated HGF isoforms that encompass the N-terminal (N) domain through kringle 1 (NK1) or through kringle 2 (NK2). We report the high-level expression in Escherichia coli of NK1 and NK2, as well as the individual kringle 1 (K1) and N domains of HGF. All proteins accumulated as insoluble aggregates that were solubilized, folded and purified in high yield using a simple procedure that included two gel-filtration steps. Characterization of the purified proteins indicated chemical and physical homogeneity, and analysis by CD suggested native conformations. Although the K1 and N-terminal domains of HGF have limited biological activity, spectroscopic evidence indicated that the conformation of each matched that observed when the domains were components of biologically active NK1. Both NK1 and NK2 produced in bacteria were functionally equivalent to proteins generated by eukaryotic systems, as indicated by mitogenicity, cell scatter, and receptor binding and activation assays. These data indicate that all four bacterially produced HGF derivatives are well suited for detailed structural analysis.

Circular Dichroism↗