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Biomedical subjects

S Kamei

Publications and source records attributed to S Kamei.

At least 73 records · Page 4Linked to original sources
PubMed1995

Two molecules of cytochrome c function as the electron donors to P840 in the reaction center complex isolated from a green sulfur bacterium, Chlorobium tepidum.

A photoactive reaction center complex was isolated from a thermophilic green sulfur bacterium, Chlorobium tepidum under anaerobic conditions. The electron transfer occurred from heme c to the photo-oxidized reaction center chlorophyll, P840+, with a half time (t1/2) of 110 or 340 microseconds at 24 or 12 degrees C, respectively. Optical measurements under multiflash excitations indicated that two hemes function as the immediate electron donors to P840+. SDS-PAGE analysis of the RC complex in combination with the N-terminal amino acid sequence analyses revealed five subunit bands; a core protein (65 kDa), the light harvesting bacteriochlorophyll alpha protein (41 kDa), a protein with 2[4Fe-4S] clusters (31 kDa), monoheme cytochrome c (22 kDa), and a 18-kDa protein whose function is unknown. The reaction center complex, thus, contains two molecules of cytochrome c per P840.

Amino Acid Sequence↗
PubMed1995

Ornithine decarboxylase is directly involved in mouse mammary carcinoma cell invasion in vitro.

To elucidate the role of ornithine decarboxylase (ODC) in cancer cell invasion, we have compared the invasiveness of mouse mammary carcinoma, FM3A and its variant cell line, EXOD, which overproduces ODC. We have found that EXOD cells showed about 5.6-fold more invasiveness through a reconstituted basement membrane (Matrigel) compared to FM3A cells. To elucidate the underlying mechanism of increased invasiveness of EXOD cells, we analyzed gelatinase activity in conditioned media derived from FM3A and EXOD cells. EXOD cells secreted approximately 3-fold 72kDa gelatinase compared to FM3A cells. Cell attachment ability to Matrigel was also studied. Although FM3a and EXOD cells showed increased attachment to Matrigel in a dose-dependent manner, EXOD cells showed higher cell attachment ability compared to FM3A cells. Anti-72kDa gelatinase neutralizing antibody suppressed EXOD cell invasion through Matrigel. Further, antisense oligonucleotides of ODC suppressed EXOD cell invasion through Matrigel. Although the causal relationship among ODC expression, gelatinase secretion and cell attachment ability remains to be elucidated, the results suggest that both overproduction of ODC and 72kDa gelatinase secretion are directly involved in increased invasiveness of EXOD cells.

Animals↗
PubMed1995

The levels of granulocyte colony-stimulating factor in the plasma of the bone marrow aspirate in various hematological disorders.

We developed a sensitive method of measurement of granulocyte colony-stimulating factor (G-CSF) by an enzyme-linked immunosorbent assay, which we applied in the plasma of the bone marrow aspirate in 70 patients with various hematological disorders. The lowest limit of detection by this method is 2 pg/ml. G-CSF was detected in all but two of the patients. Compared to the G-CSF level in normal healthy controls, those in non-Hodgkin's malignant lymphoma, aplastic anemia, agranulocytosis and multiple myeloma were significantly higher, while the level in refractory anemia was not different. The G-CSF level in acute myelogenous leukemia patients was either elevated or decreased regardless of the French-American-British subgroup. The level in acute lymphoblastic leukemia was not different from the normal value, as was that in refractory anemia with an excess of blasts, and that in chronic lymphocytic leukemia. A patient with chronic myelomonocytic leukemia showed initial elevation of G-CSF with normalization after entering complete remission. The G-CSF level in chronic myelogenous leukemia was significantly decreased, although one patient in hematological remission who was under alpha-interferon therapy showed normal levels. The level in polycythemia vera was not significantly different from the normal value. The G-CSF level for the entire group showed an inverse, although not statistically significant, correlation with the percentages of myeloid cells of the bone marrow (r = -0.174, p = 0.1703, n = 80). These results are thought to reflect the regulatory mechanism of granulopoiesis in the bone marrow in various hematological disorders, and it is concluded that this method may be of clinical use in the treatment of patients with these disorders and in the selection of candidates likely to benefit from G-CSF administration.

Agranulocytosis↗
PubMed1995

Alpha-galactosidase gene mutations in Fabry disease: heterogeneous expressions of mutant enzyme proteins.

Five point mutations were identified in unrelated Japanese Fabry disease hemizygotes: three new missense mutations, C142Y (425 G-->A), A156V (467 C-->T), and L166V (496 C-->G) in exon 3; one new splice site mutation at the 3' end of the consensus sequence in exon 4; one previously reported nonsense mutation, W44X (131 G-->A). C142Y expressed 50% of the normal enzyme protein in COS-1 cells, but catalytic activity was not detected. Both A156V and L166V expressed significant amounts of residual enzyme activity (6.7% and 9.8%) and enzyme proteins (10% each), the latter were more thermolabile at neutral pH than at acid pH, in vitro.

Adolescent↗
PubMed1995

Significance of urinary N1,N8-diacetylspermidine and N1,N12-diacetylspermine as indicators of neoplastic diseases.

N1,N8-Diacetylspermidine (Ac2Spd) and N1,N12 diacetylspermine (Ac2Spm), the occurrence of which in healthy human urine was demonstrated recently, increased much more frequently and markedly than total polyamines, acetylputrescine, N1-acetylspermidine and N8-acetylspermidine in patients with urogenital malignancies. Ac2Spd was hardly elevated in cases of benign disease, while Ac2Spm only infrequently stayed within normal limits in patients with malignant disorders. Urine samples from more than 90% of healthy persons, but fewer than 10% of patients with malignancies, gave values within normal limits for both Ac2Spd and Ac2Spm. Simultaneous reference to these diacetylpolyamines is therefore useful in distinguishing patients with malignancies from healthy persons.

Adult↗
PubMed1995

Prolonged blood circulation in rats of nanospheres surface-modified with semitelechelic poly[N-(2-hydroxypropyl)methacrylamide].

Semitelechelic poly[N-(2-hydroxypropyl)methacrylamide]s (ST-PHPMA) containing one amino end-group and differing in molecular weight were synthesized by radical polymerization in the presence of 2-aminoethanethiol (AET) as chain transfer agent. These polymers were covalently attached via amide bonds to the surface of nanospheres based on a copolymer of methyl methacrylate, maleic anhydride, and methacrylic acid. When compared to unmodified nanospheres, those with the surface modified with ST-PHPMA possessed a decreased protein (albumin, IgG, fibrinogen) adsorption in vitro, an increased intravascular half-life as well as a decreased accumulation in the liver after intravenous administration into rats. The higher the molecular weight of the ST-PHPMA, the more pronounced the changes in these properties. The results obtained have clearly demonstrated that covalently attached ST-PHPMA chains are efficient in decreasing the biorecognition of negatively charged (hydrophilic) polymer surfaces.

Acrylic Resins↗
PubMed1995

Determination of amounts of polyamines excreted in urine: demonstration of N1,N8-diacetylspermidine and N1,N12-diacetylspermine as components commonly occurring in normal human urine.

An analytical system developed for fractionating free and monoacetylated polyamines [Hiramatsu, K. et al. (1994) J. Biochem. 115, 584-589] was proved useful also in detecting diacetylpolyamines, namely N1,N8-diacetylspermidine (diAcSpd) and N1,N12-diacetylspermine (diAcSpm). Detection limits were 0.9 and 0.6 pmol (S/N = 5) for diAcSpd and diAcSpm, respectively. Analytical recovery and within-run variation were also satisfactory. Human urine samples were found to contain diAcSpd and diAcSpm. These polyamines were identified on the basis of the following observations: (i) their retention times were coincident with those of authentic samples; (ii) they were deacetylated to N8-acetylspermidine and monoacetyl- and free spermine, respectively, by acetylpolyamine amidohydrolase; and (iii) they were practically inert to direct oxidation by bacterial polyamine oxidase as were authentic samples. The amounts of eleven polyamine species including diAcSpd and diAcSpm in urine samples from 52 healthy persons were determined. Mean values for the major polyamine components were consistent with those reported by others. Although the amounts of diAcSpd and diAcSpm were very small, comprising only 1.4 and 0.46% of total polyamines, respectively, these two compounds were found to be always present in healthy human urine as regular constituents. Moreover, variation in their content among individuals was small, suggesting that excretion of these components in urine is strictly regulated.

Biogenic Polyamines↗
PubMed1995

Fracture of the tarsal navicular associated with calcaneonavicular coalition: a case report.

Fracture of the navicular occurred in a 23-year-old male with unilateral cartilaginous calcaneonavicular coalition. Inversion sprain of the left foot caused the longitudinal navicular fracture next to the coalition. En bloc resection from the beak of the calcaneus to the fracture line of the navicular including the calcaneonavicular coalition was performed, and a short leg cast was applied for 10 days. Four weeks after surgery, he returned to his preinjury level of activity and job as a long-distance truck driver. Two years and 3 months after surgery, he was totally asymptomatic and had gained a full range of subtalar motion. He had no peroneal spasm or recurrence of the coalition.

Adult↗
PubMed1995

[Development of Wernicke's encephalopathy during the period of oral food intake after a subtotal colectomy for ulcerative colitis].

A 61-year-old woman was hospitalized because of ulcerative colitis which had caused fever, vomiting and diarrhea since June 16, 1992. Then she developed toxic megacolon, and was transferred to our hospital on the 1st of July and underwent subtotal colectomy the same day. After surgery, she received intravenous hyperalimentation (IVH) which contained 1,000 Kcal/day without vitamin supplementation. From the 8th to the 13th post-operative days, she took 3/4 or more of the liquid diet which contained 1,050 Kcal, protein 35 g, carbohydrate 166 g and vitamin B1 0.59 mg per day. From the 14th to the 23rd post-operative days, she ate 4/5 or more of the oral diet which contained 1,700 Kcal/day, protein 68 g, carbohydrate 236 g and vitamin B1 0.93 mg per day. During the 7th to the 23rd day, the IVH was reduced to 800 Kcal and then 500 Kcal per day. She talked less on the 19th post-operative day, and in a few days, her level of consciousness began to decline progressively. On the 27th post-operative day, neurological examinations revealed the following: semi-coma, almost fixed pupils which were 3 mm in diameter, absent doll's eye movement to all directions, flaccid extremities with abolished deep tendon reflexes. Pertinent abnormalities on laboratory data at that time consisted of hemoglobin 7.8 g/dl and serum total protein 5.4 g/dl. Lumbar puncture revealed normal cerebrospinal fluid under normal opening pressure. Cranial magnetic resonance imaging (MRI) taken on the 27th post-operative day demonstrated, on T2-weighted images, symmetrical high intensity lesions in the periventricular areas of the third and fourth ventricles, and periaqueductal area of the midbrain.(ABSTRACT TRUNCATED AT 250 WORDS)

Colectomy↗
PubMed1994

An improved method of determining free and acetylated polyamines by HPLC involving an enzyme reactor and an electrochemical detector.

We developed an improved system for the simultaneous measurement of free and acetylated polyamines, which comprised a HPLC pump, a separation column, an enzyme reactor, and an electrochemical detector, connected in series. Polyamines were separated with an isocratic elution system, and the separated polyamines were introduced into the enzyme reactor, in which they were deacetylated and oxidized to generate hydrogen peroxide. The amount of hydrogen peroxide generated was then determined with the electrochemical detector. Analysis of a mixture of nine standard polyamines including both free forms and acetylated derivatives with this method revealed that the analytical variables were satisfactory. For the analysis of polyamines in urine, pretreatment of samples with a weakly acidic ion exchange resin was necessary to reduce the interfering substances present in the urine. On successive determinations of polyamines in a urine sample, the coefficients of variation obtained were below 5.4%, except that for spermine (27.6%), and the analytical recovery rates were above 90%, except that for acetylputrescine (78.5%). The correlation coefficient between the total polyamine content in urine estimated by our method and that obtained by means of a commercially available enzymatic assay system was calculated to be 0.98, and the regression equation was expressed as y = 0.81 x + 0.89.

Acetylation↗
PubMed1994

Amino acid sequence and inhibitory activity of rhesus monkey tissue factor pathway inhibitor (TFPI): comparison with human TFPI.

Rhesus monkey cDNA for tissue factor pathway inhibitor (TFPI) was cloned by means of the reverse transcriptase-polymerase chain reaction, using liver mRNA, and its nucleotide sequence was determined by sequencing five independent clones. Monkey TFPI was found to have a signal peptide of 28 amino acid residues and to be a mature protein of 276 amino acid residues, in which three and seventeen amino acid residue substitutions compared to human TFPI were found, respectively. All the cysteine residues, three putative carbohydrate-linked asparagine residues, and the P1 amino acid residues of each of the three Kunitz inhibitor domains were conserved in the two species. Recombinant monkey TFPI (rTFPI) was isolated from the culture medium of transformed Chinese hamster ovary cells. Amino acid sequence analysis and immunoblotting analysis, using polyclonal and monoclonal antibodies, showed that the carboxyl-terminal basic part of Rhesus monkey rTFPI had been truncated. The inhibitory activity of monkey rTFPI was compared with that of human rTFPI without the carboxyl-terminal basic part. The prothrombin time of human plasma was slightly more prolonged by the addition of monkey rTFPI than by that of human rTFPI. However, no significant differences were found between the potencies of human and monkey rTFPI as to the inhibition of factor Xa and tissue factor-factor VIIa complex.

Amino Acid Sequence↗
PubMed1994

New non-invasive rapid diagnosis of herpes simplex virus encephalitis by quantitative detection of intrathecal antigen with a chemiluminescence assay.

A technique for detecting herpes simplex virus (HSV) antigen in CSF by measuring the antigen-antibody complex-activated complement-stimulated chemiluminescence in normal granulocytes was applied to 17 CSF samples from 10 patients with herpes simplex virus encephalitis (HSVE), and 26 samples from 22 patients with a non-HSVE brain illness. All CSF samples taken from the 5th to the 38th day (including seven from the 5th to the 10th day) of HSVE were positive, whereas those for all non-HSVE samples were negative. This assay required only five hours to yield a result.

Adolescent↗
PubMed1994

Capillary leak syndrome likely the result of granulocyte colony-stimulating factor after high-dose chemotherapy.

Two cases of malignant lymphoma complicated with capillary leak syndrome following super high-dose chemotherapy and administration of granulocyte colony-stimulating factor (G-CSF) are presented. Subsequent to the nadir of granulocytes, and at the stage of rapid increase of granulocytes, the symptoms of fever, hypotension, dyspnea, pleural effusion and edema appeared, and laboratory data revealed hypoxia, hypocapnia and hypoalbuminemia. In addition, an abscess-like lesion was observed in the liver in one patient. After the administration of G-CSF was ceased or decreased, and pulse therapy with methylprednisolone was initiated, these symptoms disappeared quickly.

Adult↗
PubMed1994

A congenital variant of thrombotic thrombocytopenic purpura in two siblings.

We describe two siblings affected by chronic relapsing thrombotic thrombocytopenic purpura from infancy. The elder brother, a 12-year-old boy had 50 such episodes characterized by acute onset of fever, headache, drowsiness, vomiting, dark urine, thrombocytopenia and anemia. The younger sister, a 6-year-old girl, had 8 episodes with the same clinical manifestations. Petechiae and ecchymoses on the extremities were present throughout their lives. Furthermore, anemia with evidence of red blood cell fragmentation and thrombocytopenia were present chronically. Periodical transfusion of frozen fresh plasma prevented recurrent episodes. These cases suggest that there is a congenital variant of thrombotic thrombocytopenic purpura.

Child↗
PubMed1994

[A successful delivery three years after the onset of multiple fungal liver abscess in a patient with acute lymphoblastic leukemia].

A 25-year-old woman was diagnosed as having the multiple fungal liver abscess which developed just after the re-induction chemotherapy, 13 months after the onset of acute lymphoblastic leukemia. Although chemotherapy for leukemia was suspended, her leukemia did not relapse. The multiple fungal liver abscess was successfully treated with anti-fungal drugs for the following 12 months. Three years after the onset of the fungal abscess, she married, became pregnant and vaginally delivered a healthy female infant at full term. In this way, it was demonstrated that a normal pregnancy and delivery could be expected even in patients who had received intensive chemotherapy and had recovered from the fungal abscess.

Adult↗
PubMed1993

Unusual neurologic manifestations associated with Epstein-Barr virus infection.

We describe two patients who displayed unusual neurologic manifestations associated with reactivation of latent Epstein-Barr virus (EBV) infection. The patients included a 34-year-old woman who suffered from meningoencephalitis presenting with symptoms identical to those of transient global amnesia, and a 57-year-old man with jumbling phenomenon and gait ataxia. The protean neurologic manifestations of EBV infection underscore the need to suspect this infection in any acute neurologic disorders of possible infectious origin irrespective of the age of the patient.

Adult↗