Biomedical subjects

T Sakaguchi

Publications and source records attributed to T Sakaguchi.

At least 181 records · Page 10Linked to original sources

PubMed1993

Orally administered prostaglandin E1 derivative can enhance liver regeneration in partially hepatectomized rats.

The effect of orally administered 17(S),20-dimethyl-6-oxo prostaglandin E1 (PGE1) methyl ester (OP) on liver regeneration was examined in 66% hepatectomized rats. Administration of OP increased the mitotic index of the hepatocyte 3 days after hepatectomy, and the mitotic index response due to OP was dose dependent. The OP administration had no effect on food intake, but reduced water intake. The serum scores relative to nutrition and hepatic function showed transient change after OP administration, whereas the serum blood urea nitrogen level indicated a slight renal dysfunction with OP. The fat store in the body was transiently reduced. These observations lead us to conclude that orally administered OP is capable of stimulating liver regeneration without serious systemic effects.

Administration, Oral↗

PubMed1993

Detection and removal of Escherichia coli using fluorescein isothiocyanate conjugated monoclonal antibody immobilized on bacterial magnetic particles.

A novel fluoroimmunoassay method using bacterial magnetic particles for the highly sensitive detection of bacteria has been developed. Fluorescein isothiocyanate (FITC) conjugated monoclonal anti-Escherichia coli antibody was immobilized onto bacterial magnetic particles (BMPs) using a heterobifunctional reagent, N-succinimdyl 3-(2-pyridyldithio)propionate (SPDP). E. coli cells were reacted with FITC-antibody-BMP conjugates for 15 min in an inhomogeneous magnetic field which enhanced aggregation. The cell/BMP complexes sedimented, causing relative fluorescence intensity of the solution to decrease with increasing microbial cell concentration. A linear relationship was obtained between the relative fluorescence intensity and cell concentration in the range of 10(2)-10(6) cells/mL. Selectivity of this detection system was satisfactory. Monoclonal antibody immobilized on BMPs was also applied to the specific removal of E. coli from the bacterial suspension.

Antibodies, Monoclonal↗

PubMed1993

Human fetal-to-adult globin gene switching in transgenic mice: persistent expression of the G gamma-globin gene in the Japanese HPFH.

We linked a 3.3 kb fragment containing the human gamma-globin gene together with a 5.5 kb fragment containing the human beta-globin gene. This construct was introduced into the germ line of mice. Analysis of the resulting transgenic mice showed that expression of the human gamma- and beta-globin genes were regulated as that of the mouse embryonic and adult globin genes and human gamma-to-beta globin switching was reconstructed in the mice. By replacing the gamma-globin gene in the construct with modified counterparts, this transgenic mouse system enables us to analyze cis-acting elements essential for erythroid-specific and developmental stage-specific expression of the test gene under the condition in which human beta-globin gene expression is regulated. In this system expression of the G gamma-globin gene bearing the point mutation found in a Japanese patient of hereditary persistence of fetal hemoglobin (HPFH) (1) persisted at a equivalent level to beta-globin expression in fetal and adult mice.

Aging↗

PubMed1993

Reduced diameter and conduction velocity of myelinated fibers in the sciatic nerve of a neurofilament-deficient mutant quail.

The diameter and conduction velocity of myelinated fibers in the sciatic nerve isolated from neurofilament-deficient quail ('quiver') were compared with those from wild quail. The diameter was significantly reduced in quiver, however, the frequency distribution formed three peaks as did that observed in the wild. The fibers were categorized in three groups possessing different conduction velocity. The conduction velocity appeared to be proportional to the diameter in each strain, and was significantly reduced in quiver. These results indicate that, although the diameter and conduction velocity are reduced in quiver fiber, the correlation between the parameters observed in wild quail is still preserved.

Animals↗

PubMed1993

Uptake and recovery of gold by immobilized persimmon tannin.

Some attempts were made to recover gold from aqueous systems using immobilized persimmon tannin. This adsorbent adsorbed gold from solutions containing hydrogen tetrachloroaurate (III) with high efficiency, whereas there was minimal adsorption from solutions containing gold(I) sodium thiomalate and sodium dicyanoaurate(I). The adsorption of gold was rapid, and was affected by the pH of the solution, temperature, external gold concentration and amount of adsorbent. Adsorbed gold was easily desorbed with 1 mol dm-3 thiourea solution, indicating that immobilized persimmon tannin can be repeatedly re-used for the recovery of gold using adsorption-desorption cycles.

Adsorption↗

PubMed1993

A pharmacological analysis of prostaglandin E1 on portal blood flow after partial hepatectomy in rats.

Portal venous flow (PVF) and portal venous pressure (PVP) were examined after the jugular or portal injection of Prostaglandin E1 (PGE) in rats partially hepatectomized by either 40% or 66%. In the 66% hepatectomized animals, the jugular injection of PGE at 5.0 micrograms/kg/min produced an increase in PVF concomitant with a fall in systemic arterial pressure (SAP), while PVP remained unchanged. The portal injection of PGE at 0.5 micrograms/kg/min increased PVF to a level equivalent to that evoked by the jugular injection of 5.0 micrograms/kg/min PGE, without any change in SAP. PVP was reduced synchronistically with an increase in PVF. The PVF response to a portal injection of PGE at 0.5 micrograms/kg/min was not reproduced in liver intact rats. These results suggest that PGE is potent in increasing PVF in the partially resected condition of the liver and that the portal vascular bed is involved in this response.

Alprostadil↗

PubMed1993

Enhanced liver regeneration in rats treated with 15-deoxyspergualin alone and in combination with FK 506.

The effects of 15-deoxyspergualin (DSG) alone and in combination with FK 506 (FK) on liver regeneration after 2/3 hepatectomy was studied. The administration of 5 mg/kg DSG increased the liver weight as a percentage of the body weight (RLW) in the 5 days following the hepatectomy. This enhanced regeneration was not affected if interleukin(IL)-2 was also given. The combination of 1 mg/kg DSG and 0.05 mg/kg FK induced the highest values for RLW. The amounts of food and water intake increased in the DSG and FK combined group. Blood chemistry indicated that the combined administration of DSG and FK could reduce side-effects more effectively than separate administration. These observation led us to conclude that DSG has a stimulating potency in liver regeneration by means of direct suppression of T cell activation, and there is a synergistic effect on regeneration by DSG and FK.

Animals↗

PubMed1993

Motility function of the esophagus before primary anastomosis in esophageal atresia.

Two patients with a long gap esophageal atresia without tracheoesophageal fistula underwent an esophageal manometric study before primary anastomosis and one of them underwent an identical study after operation. Before operation both patients showed peristaltic contraction in the proximal esophagus when swallowing which was always followed by a coordinated contraction of the distal esophagus the same as in that of the normal esophagus. These peristaltic contractions induced a reflex relaxation of the lower esophageal sphincter (LES). After operation the manometric studies of the repaired esophagus demonstrated an abnormal esophageal motility, with simultaneous contractions occurring when swallowing in the proximal to the distal esophagus. In addition, the reflex relaxation of LES was incomplete. These data suggest that even if the intraluminal continuity is defective, the esophageal motility function is not disturbed in the proximal to distal esophagus in preoperative esophageal atresia, and that intraoperative mobilization and denervation may be suggested to be an important factor in esophageal dysmotility even when esophageal atresia is successfully repaired.

Anastomosis, Surgical↗

PubMed1993

Distribution of radioisotopic beryllium in mice after administration by various routes of injection.

A 7BeCl2 solution containing 0.5 micrograms Be per mouse was injected subcutaneously, intraperitoneally, intramuscularly, intrathoracically, and intravenously, and distribution was observed for periods up to 1 wk. 7Be was excreted more rapidly following intravenous injection than by the other routes of injection. The amount of Be found in the liver or the spleen was substantial at 1 d after intraperitoneal injection. It increased more in the spleen at 7 d after either intraperitoneal or intrathoracic injection. On the other hand, the amounts of Be stayed almost constant in the kidneys, by the various routes of injection. When injected intrathoracically, the amounts of Be in the heart and the lung were greater than when administered by the other routes of injection. The amounts of Be in the femurs of mice administered by these routes of injection, except with intravenous injection, were greater than in the other organs. The percentage of 7Be in the mineralized bone was 90% of that of 7Be in the femurs when injected intraperitoneally or intrathoracically. However, the ratio of Be in the mineralized bone to that in the bone marrow was 3 to 2. Beryllium had thus a closer affinity for the femurs than for the other organs investigated, with the different modes of administration used. The amount of Be in the entire skeleton was estimated to be substantial. Within the limitations of 1 wk of exposure, the skeleton would appear to be a critical organ. This would suggest that osteosarcomas may occur following administration of Be to laboratory animals for a long-term period.

Animals↗

PubMed1993

Endoscopic retrograde cholangiography in the nonsurgical management of blunt liver injury.

Injury to the intrahepatic bile duct has not been routinely examined in patients with blunt liver injury, despite the risk of formation of a biloma and hemobilia. In this study we examined the role of endoscopic retrograde cholangiography (ERC) in the evaluation of blunt liver injuries. Sixty-four of 106 (60.3%) patients with blunt hepatic injuries, admitted from April 1986 through March 1992, were managed nonsurgically; ERC was performed in conjunction with computed tomographic (CT) scanning to rule out injury to the bile duct in 28 patients. Injury to the bile duct was detected in six patients (21.4%), five of whom developed a biloma. Patients with hepatic parenchymal injuries that were observed on the CT scans were at greatest risk for injury to the intrahepatic bile duct, and our data suggested that the incidence of injury to the intrahepatic bile duct after blunt hepatic trauma is higher than previously reported. Patients with serious hepatic parenchymal injuries who are candidates for nonsurgical management should be considered for ERC to exclude the possibility of injury to the bile duct.

Adolescent↗

PubMed1993

Expression of the HN, F, NP and M proteins of Sendai virus by recombinant vaccinia viruses and their contribution to protective immunity against Sendai virus infections in mice.

Recombinant vaccinia viruses (RVVs) expressing each of the haemagglutinin-neuraminidase (HN), fusion (F), nucleocapsid (NP) and matrix (M) proteins of Sendai virus were constructed to investigate their capacities to induce protective immunity against Sendai virus infections. The proteins expressed in cultured cells appeared to be authentic with respect to their antigenicity, electrophoretic mobility, surface expression of the HN and F proteins and, in the case of the HN protein, biological activities. Mice inoculated intranasally with these RVVs developed serum antibodies to the respective Sendai virus proteins, suggesting their in vivo expression. In mice immunized with RVV carrying either the HN or the F gene, growth of the challenging Sendai virus was almost completely suppressed in the lung, indicating their capacities to induce effective protective immunity against Sendai virus infections. In contrast, in mice immunized with RVV carrying the NP or M gene, the challenging virus propagated as well as in the control mice, but the virus titres were significantly lower at the late stage of infection than those in the control mice, suggesting that they can also induce protective immunity especially at the late stage of the challenge infection.

Animals↗

PubMed1993

[Biological characters of the clinically isolated strains of Escherichia coli O157:H7 in Canada].

Biological characters of enterohemorrhagic Escherichia coli (EHEC) strains isolated from food poisoning cases in Canada, 1987-1988 were examined in comparison with that isolated in Saitama, 1990. The Saitama strain was found to belong to biotype I, and biotypes I and II were found in Canada. Most of the strains including the Saitama strain were found to have siderophilins suggesting their advantageous growth in vivo. An enteroinvasive strain with 140 megadalton (Md) plasmid and two colicinogenic strains with 4.8 Md plasmids were detected. All strains were found to have 60 Md plasmids. This plasmid might be specific for this serotype. A few strains were resistant to streptomycin (SM) and/or tetracycline (TC), and a strain transferred its SM-TC resistances by conjugation. Many strains including the Saitama strain were found to produce vero cytotoxin (VT) types 1 and 2 (VT1 and VT2). A few type 2 and untypable toxin producing strains were also detected. VT titers produced by untypable toxin producing strains were over 10 times lower than those by other strains. High annealing temperature for PCR amplification of VT1 gene and a variety of annealing temperatures of VT2 gene suggested that the nucleotide sequences for VT1 gene were well preserved, but that those for VT2 might have some mutations.

Animals↗

PubMed1993

Evolutionary relationships among Magnetospirillum strains inferred from phylogenetic analysis of 16S rDNA sequences.

We have investigated the evolutionary relationships between two facultatively anaerobic Magnetospirillum strains (AMB-1 and MGT-1) and fastidious, obligately microaerophilic species, such as Magnetospirillum magnetotacticum, using a molecular phylogenetic approach. Genomic DNA from strains MGT-1 and AMB-1 was used as a template for amplification of the genes coding for 16S rRNA (16S rDNA) by the polymerase chain reaction. Amplified DNA fragments were sequenced (1,424 bp) and compared with sequences for M. magnetotacticum MS-1 and Magnetospirillum gryphiswaldense MSR-1. Phylogenetic analysis of the aligned 16S rDNA sequences indicated that the two new magnetic spirilla, AMB-1 and MGT-1, lie within the alpha subdivision (alpha-1) of the eubacterial group Proteobacteria and are closely related to Rhodospirillum fulvum and to several endosymbiotic bacteria. Strains AMB-1, MGT-1, and MS-1 formed a cluster, termed group I, in which they were more closely related to each other than to group II, which contained M. gryphiswaldense MSR-1. Group I strains were also physiologically distinct from strain MSR-1. Sequence alignment studies allowed elucidation of genus-specific regions of the 16S rDNA, and oligonucleotide primers complementary to two of these regions were used to develop a specific polymerase chain reaction assay for detection of magnetic spirilla in natural samples.

Bacteria↗

PubMed1993

F0-containing noninfectious Sendai virus can initiate replication in mouse lungs but requires a relatively long incubation period.

The replication of LLC-MK2-grown noninfectious Sendai virus, containing exclusively fusion (F) glycoprotein precursors, was examined in the mouse lung to study the accessibility of virus inoculated intranasally to the virus activator present in the lung. When mice were intranasally inoculated with various doses of the virus after in vitro activation with trypsin, the 50% mouse infectious dose (MID50) was determined to be 0.7 cell-infectious units (CIU) per mouse, indicating that one infectious unit of Sendai virus is enough to initiate replication in the mouse lung and that the present experimental system is highly sensitive. On the other hand, in mice inoculated with virus not treated with trypsin, virus replication in the lung was recognized even in mice inoculated with samples containing no infectious virus, and the MID50 was determined to be 67.5 CIU per mouse (here, CIU were assayed after in vitro trypsin treatment). When mice were infected with 20 MID50 of trypsin-treated infectious and untreated noninfectious viruses (an approximately 100-fold greater amount of noninfectious virus than of infectious virus was used), the noninfectious virus was found to require 2 more days of incubation than the infectious virus, and many of the F proteins synthesized in the lungs of mice infected with the F0-containing virus were present in the cleaved form. In addition, the infection of mice with noninfectious virus was strongly suppressed by aprotinin, a serine protease inhibitor. These results indicate that Sendai virus can initiate replication in the mouse lung even with the F0-containing noninfectious virus and strongly suggest that this infection process is mediated by cleavage activation of the F0 proteins of inoculated viruses by a serine protease(s) present in the lumen of the mouse respiratory tract but that activation of the noninfectious virus is an inefficient process.

Animals↗

PubMed1993

Hepatic branch vagotomy can suppress liver regeneration in partially hepatectomized rats.

The role of the vagus nerve in liver regeneration after partial hepatectomy was studied by comparing the effects of hepatic branch vagotomy with those of hepatic branch sympathectomy in rats. The liver weight as a percentage of body weight decreased significantly 7 days after vagotomy compared with the controls and this was associated with a reduction in food intake. There was no difference in the liver weights between the control rats and the pair-fed vagotomized rats. Hepatic sympathectomy had no significant effect on the liver weight. The serum scores indicating hepatic function showed no difference between the control and the vagotomized rats except alkaline phosphatase. The concentration of insulin was unchanged. The number of mitotic hepatocytes remained high at 7 days after vagotomy. These observations led us to conclude that the vagus nerve stimulates liver regeneration, and its effect depends on vagal factors directly and specifically.

Alanine Transaminase↗

PubMed1993

[A case of breast cancer with thrombosis during treatment of lung metastasis].

A 74-year-old female with lung metastasis of breast cancer was treated with chemo-endocrine therapy (intravenous administration of epirubicin at 30 mg/2w, oral administration of UFT at 400 mg/day, alternate oral administration of medroxyprogesterone acetate at 800 mg/day and tamoxifen at 40 mg/day) and immuno-therapy (intravenous administration of lentinan at 2 mg/w). Lung tumors decreased in size and number. At the same time, deep vein thrombosis of the lower extremities occurred, which caused multiple pulmonary embolization. In this case, several factors were suggested to cause thrombosis in the advanced or recurrent breast cancer patient.

Administration, Oral↗

PubMed1992

Enhanced gastric acid secretion induced by gastrin can be suppressed partially by glucose injection into the medullary nuclei in rats.

Gastric acid outputs after glucose injection into the nucleus of the vagus nerve (X) or into the nucleus of the tractus solitarius (SOL) were examined in rats with tetragastrin. The enhanced acid output caused by gastrin was partially inhibited by glucose injection into the X or SOL. Glucose injection into the X depressed acid output in a dose-dependent fashion, but a non-dose-dependent response in acid output was seen when glucose was injected into the SOL. There was no interaction between the X and SOL in acid response due to glucose. These findings suggest that glucose modulates gastric acid secretion stimulated by gastrin at the medullary level, and that such a modulation is characterized by the medullary X or SOL, separately.

Animals↗

PubMed1992

Mouse monoclonal antibodies which recognize a human (beta 1-4)galactosyl-transferase associated with tumor in body fluids.

Mouse monoclonal antibodies against human (beta 1-4)galactosyl-transferase (GalT) purified from human ovarian tumor effusion fluids were prepared and characterized. GalT purified from normal human plasma showed a single diffused band in nondenaturing polyacrylamide gel electrophoresis, but GalT purified from human ovarian tumor effusion fluids showed several oligomeric bands and a monomeric band in nondenaturing polyacrylamide gel electrophoresis. These oligomeric bands were dissociated into monomer by urea treatment and polymerized by a 2-mercaptoethanol treatment. Nine monoclonal antibodies (MAb) were prepared by immunization of purified GalT from human ovarian tumor effusion fluids and classified into three groups. Type I MAbs (MAb8611, MAb8913, and MAb8919) reacted only to the GalT monomer. Type II MAbs (MAb4880, MAb8507, and MAb8628) reacted to both the GalT monomer and the GalT polymer. Type III MAbs (MAb7907, MAb8513, and MAb8677) reacted only to the GalT polymer. These MAbs except MAb7907 could recover GalT enzyme activity from effusion fluids by immunoprecipitation. A fraction passed through MAb8513 affinity chromatography still showed reactivity to MAb8919, demonstrating that an epitope of MAb8513 resides on a minor part of GalT. A sandwich immunoassay (MAb8513-MAb8628HRP) was developed, and serum samples from ovarian cancer patients and benign ovarian patients were tested. The levels of sandwich immunoassay of serum samples from cancer were elevated significantly compared to those from benign and did not necessarily correlate to total GalT enzyme activity in serum samples. These results suggested that MAb8513 (Type III) might recognize a unique GalT associated with tumor (GAT).

Animals↗