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Biomedical subjects

K Fujikawa

Publications and source records attributed to K Fujikawa.

At least 127 records · Page 7Linked to original sources
PubMed1997

Radiographic changes in the patella after total knee arthroplasty without resurfacing the patella. Comparison of osteoarthrosis and rheumatoid arthritis.

The necessity of patellar resurfacing has aroused considerable controversy. Between 1986 and 1996, we have routinely performed 208 primary total knee arthroplasties (TKAs) without resurfacing the patella. However, we have occasionally observed gradual postoperative patellar deterioration which caused peripatellar pain. This study observed the radiographic changes in the patella after TKA without resurfacing the patella to assess the effect of the changes on the clinical results. Sixty out of 208 TKAs were assessed in this study. The original diagnoses were osteoarthrosis (OA) in 17 joints and rheumatoid arthritis (RA) in 43 joints. Fourteen patients (23.3%) complained of postoperative peripatellar pain: 2 of the 17 patients with OA (11.8%) and 12 of the 43 with RA (27.9%). Lateral tilt of the patella slightly decreased with time, but lateral shift increased slightly. Patellar length and width increased throughout the follow-up period. The thickness of the patella, especially in the RA cases, significantly (Mann-Whitney, p < 0.05) decreased with time. According to these radiographic findings, as time passed the thickness of the patella decreased, its length and width increased, and the patella as a whole became flattened. On examining the effect of this flattening on postoperative pain, it was found that about 70% of those patients whose patellar thickness had decreased to 80% or less complained of peripatellar pain. In the case of the OA patients, however, there was no statistically significant correlation between patellar flattening and pain. It is concluded that patellar resurfacing should be considered for the patient with rheumatoid arthritis. Because patellar flattening did not develop in many patients with OA and few of them complained of peripatellar pain, patellar resurfacing should not be performed routinely.

Activities of Daily Living↗
PubMed1997

Spinal fusion using a vascularized fibular bone graft for a patient with cervical kyphosis due to neurofibromatosis.

We performed an anterior spinal fusion using a vascularized fibular bone graft combined with posterior fusion for a patient with severe cervical kyphosis due to neurofibromatosis. The kyphosis was corrected from 85 degrees preoperatively to 38 degrees postoperatively. A vascularized fibular bone graft is a useful surgical procedure in selected patients to obtain successful bony union.

Adolescent↗
PubMed1997

Prognostic criteria in patients with prostate cancer: Gleason score versus volume-weighted mean nuclear volume.

Gleason's score (GS) has been reported to be the most valuable prognostic factor in cases of prostate cancer. GS is solely dependent on the histological architecture of the prostate cancer, but, it seems doubtful that histological patterns are sufficient for evaluating the degree of malignancy of prostate cancer. We previously reported that the estimation of volume-weighted mean nuclear volume (MNV) might be a more useful prognosticator for prostate cancer than subjective histological grading. However, the previous study was conducted on patients treated in a single hospital, and the number of subjects was too small to draw a definitive conclusion. In this study, we analyzed a larger number of subjects at another institution using a blinded study design. A retrospective prognostic study of 195 patients with prostate cancer diagnosed between January 1966 and December 1988 at Kyoto University Hospital, and treated by conservative therapy, was conducted. Unbiased estimates of MNV were compared with the clinical stage and histological grading according to GS with regard to the prognostic value. Univariate analysis revealed that estimates of MNV, clinical stage, and GS all correlated significantly with disease-specific survival in cases of prostate cancer. Multivariate analysis of all cases also revealed that all of these factors were significant independent prognosticators of disease-specific survival. However, focusing on clinically localized cases (stages A, B, and C), multivariate analysis revealed that the estimation of MNV was the only powerful prognosticator of prostate cancer. This study indicates that the estimation of MNV is prognostically equal or superior to GS in cases of prostate cancer. We emphasized that the estimates of MNV is a more objective method for histological grading to predict the malignant potential of prostate cancer.

Aged↗
PubMed1996

Secretory production of recombinant urokinase-type plasminogen activator-annexin V chimeras in Pichia pastoris.

To produce a thrombi-targeting plasminogen activator, we expressed a fused gene that contains a modified pre-sequence of Mucor pussilus rennin (MPR) followed by a chimeric gene of single-chain urokinase-type plasminogen activator (scu-PA)::annexin V (AV). The fused gene was ligated into an integrative vector, under the control of the alcohol oxidase 1 (AOX1) promoter (p), and transformed into Pichia pastoris. Transformants were monitored for the secretion of fibrinolytic activity. The highest expressing clone, HB225, secreted as much as 600 international units (IU) of fibrinolytic activity per ml of culture medium under optimal conditions. It contained three tandem copies of the full-size vector disruptively integrated into the AOX1 sequence. Western blot analysis revealed that the secreted chimera was highly susceptible to proteolysis. Addition of excess amino acids (aa) to the culture medium minimized the degree of proteolysis. Two major species of chimera, 85 and 65 kDa, were then isolated from the culture medium. The former was the intact form consisting of a single-chain and showing full enzyme activity after activation by plasmin. The latter was an enzymatically processed form consisting of two chains held by a disulfide bond, having full enzyme activity without activation. Both chimeras exhibited calcium-dependent phospholipid (PL)-binding affinities similar to the parent AV.

Amino Acid Sequence↗
PubMed1996

Fatal embryonic bleeding events in mice lacking tissue factor, the cell-associated initiator of blood coagulation.

Tissue factor (TF) is the cellular receptor for coagulation factor VI/VIIa and is the membrane-bound glycoprotein that is generally viewed as the primary physiological initiator of blood coagulation. To define in greater detail the physiological role of TF in development and hemostasis, the TF gene was disrupted in mice. Mice heterozygous for the inactivated TF allele expressed approximately half the TF activity of wild-type mice but were phenotypically normal. However, homozygous TF-/- pups were never born in crosses between heterozygous mice. Analysis of mid-gestation embryos showed that TF-/- embryos die in utero between days 8.5 and 10.5. TF-/- embryos were morphologically distinct from their TF+/+ and TF+/- littermates after day 9.5 in that they were pale, edematous, and growth retarded. Histological studies showed that early organogenesis was normal. The initial failure in TF-/- embryos appeared to be hemorrhaging, leading to the leakage of embryonic red cells from both extraembryonic and embryonic vessels. These studies indicate that TF plays an indispensable role in establishing and/or maintaining vascular integrity in the developing embryo at a time when embryonic and extraembryonic vasculatures are fusing and blood circulation begins.

Animals↗
PubMed1996

Preparation and characterization of a disulfide-linked bioconjugate of annexin V with the B-chain of urokinase: an improved fibrinolytic agent targeted to phospholipid-containing thrombi.

A conjugate of annexin V and the B-chain of urokinase was prepared and its fibrinolytic properties were studied. First, a mutant of annexin V was constructed with an N-terminal extension of six amino acids (Met-Ala-Cys-Asp-His-Ser) and with Cys316 mutated to Ser; this molecule was expressed in Escherichia coli. The urokinase B-chain was prepared by limited reduction of the interchain disulfide bond between the A- and B-chains of urokinase. These two molecules were then then connected by a disulfide bond and purified to yield a 1:1 stoichiometric conjugate. The conjugate had the same catalytic activity as urokinase against a synthetic substrate, Glt-Gly-Arg-MCA, and a similar plasminogen activating activity. The conjugate showed the same binding affinity for phosphatidylserine-containing membranes as annexin V. The in vitro fibrinolytic activity of the conjugates on clots prepared from platelet-rich plasma was comparable to that of urokinase. However, the conjugate showed 3-4-fold stronger in vivo thrombolytic activity than urokinase in a rat pulmonary embolism model, while having essentially the same plasma clearance rate as urokinase or B-chain. These results show that annexin V is a useful agent for targeting plasminogen activators to phospholipid-containing thrombi.

Amino Acid Sequence↗
PubMed1996

Male-mediated teratogenesis: spectrum of congenital malformations in the offspring of A/J male mice treated with ethylnitrosourea.

Male mice of inbred strain A/J were intraperitoneally treated with ethylnitrosourea (ENU). On day 64-82 posttreatment, the males were mated with untreated virgin females of the same strain. Copulation involved sperm that were spermatogonial stem cells at the time of treatment. On day 18 of gestation, viable fetuses were inspected for external malformations. The most common malformation to occur spontaneously in the control group was cleft palate or cleft lip. Similarly, in the ENU-treated series, cleft palate or cleft lip was the predominant malformation, the frequency (15%) of which was significantly increased in the highest dose group (5 x 50 mg/kg) compared to control (8%). Based on these results and other data, we propose that a large fraction of external malformations in fetuses from mutagenized paternal germ cells are a result of increased yields of spontaneously occurring malformations.

Abnormalities, Drug-Induced↗
PubMed1996

Bilateral renal cell carcinoma in a patient with tuberous sclerosis.

A case of pure bilateral renal cell carcinoma (RCC) in a 21-year-old female diagnosed as having tuberous sclerosis is reported. She underwent a left nephrectomy because of her loss of appetite, possibly caused by the tumor compressing her intestines. The preoperative CT scan showed the presence of adipose tissue in bilateral renal tumors, which is highly suggestive of angiomyolipoma (AML). Histological examination, however, revealed no area or component of the tumor with features characteristic of AML.

Adult↗
PubMed1996

Dosimetry of mixed neutron and gamma radiation with paired Fricke solutions in light and heavy water.

Paired Fricke solutions, made up from light water or heavy water and 0.8N in H2SO4 and 1 mM in Fe(NH4)2(SO4)2 and NaCl, were calibrated with 60Co gamma rays and with mixed neutron and gamma radiation from a 252Cf source. Absorbance increases, AL and AH, in light- and heavy-water Fricke dosimeters, respectively, increased with fast-neutron and gamma-ray tissue doses, Dn (GY) and D gamma (GY), of the mixed radiation as follows: AL = 0.00178Dn + 0.00371D gamma; AH = 0.00121Dn + 0.00442 D gamma. G-values of 7.2 and 5.5 were obtained for 252Cf neutrons in light- and heavy-water Fricke dosimeters, respectively. When we applied the pair of equations to AL and AH values observed after exposure to mixed radiation in a nuclear reactor, resulting Dn and D gamma values agreed within 10% to doses measured with paired ionization chambers. Doses required for Fricke dosimeters were 5 Gy or more. In contrast, we found that micronuclear yields in onion roots can measure the neutron component of mixed radiation fields at the order of 10 cGy with reasonable accuracy even if the neutron to gamma-ray dose ratio is unknown.

Californium↗
PubMed1996

[Prognostic criteria in patients with renal pelvic and ureteral cancers--clinical value of volume weighted mean nuclear volume].

A retrospective, prognostic study was performed on 22 patients with transitional cell carcinoma of the upper urinary tract seen between Dec. 1982 and Jun. 1995. Unbiased estimates of volume weighted mean nuclear volume (MNV) were compared with age at the time of diagnosis, muscle invasion, and histological grading according to World Health Organization (WHO) classification on the prognostic value. Estimates of MNV were significantly correlated (p = 0.0135) only with disease-specific survival of transitional cell carcinoma of the upper urinary tract, contrary to age at the time of diagnosis (p = 0.4865), and muscle invasiveness (p = 0.1756). The analysis was not conclusive with regard to the WHO classification as the prognostic factor in this study. Estimates of MNV also were significantly correlated (p = 0.0325) with disease-specific survival in patients diagnosed histologically as grade 2. These findings indicate that estimates of MNV are useful for determining the prognosis of transitional cell carcinoma of the upper urinary tract.

Aged↗
PubMed1995

Prourokinase-annexin V chimeras. Construction, expression, and characterization of recombinant proteins.

Annexin V is a human protein that binds with high affinity to the abundant phosphatidylserine molecules exposed on activated platelets and accumulates selectively in thrombi after intravenous administration in animal models of arterial thrombosis. We designed two chimeras that use annexin V as a means to target thrombolytic agents to platelet-containing thrombi: prourokinase (1-411)-annexin V (1-320); and prourokinase (144-411)-annexin V (1-320) (amino acid numbers of parent proteins given in parentheses). Chimeras were produced by cytoplasmic expression in Escherichia coli, refolded, and purified in single-chain form. Both chimeras had the same specific activity as annexin V in binding to cell membranes containing exposed phosphatidylserine. After activation with plasmin, both chimeras had specific amidolytic activity similar to that of urokinase. Both chimeras activated plasminogen in vitro with kinetic parameters similar to those for urokinase, and both showed full activity compared to urokinase in an assay of clot lysis in vitro. This study shows the feasibility of producing chimeric plasminogen activators in which annexin V provides the thrombus-targeting component; although not yet tested in vivo, such chimeras may have advantages over antibody-based targeting agents.

Amino Acid Sequence↗
PubMed1995

Prognostic criteria in patients with stage D2 prostate cancer. Correlation with mean nuclear volume.

BACKGROUND: Histologic grading, especially the Gleason score (GS), is considered to be of value in determining the prognosis of patients with prostate cancer. However, subjective histologic grading is characterized by low reproducibility. Conversely, estimates of mean nuclear volume (MNV), developed by Gunderson and Jensen based on a stereologic technique, is a method with high reproducibility. Furthermore, it has been reported that MNV provides an accurate prognosis of bladder cancer. In this study MNV was compared with two histologic grading methods in determining the prognosis of Stage D2 prostate cancer. METHODS: A retrospective, prognostic study of 31 patients with Stage D2 prostate cancer treated with transurethral resection of the prostate or needle biopsy between January, 1983, and July, 1994, was performed. Unbiased estimates of MNV were compared with age at the time of diagnosis, histologic grading according to World Health Organization (WHO) classification, and GS on the prognostic value. RESULTS: Age at the time of diagnosis, WHO classification and GS had no value as prognostic criteria, and only MNV correlated significantly with prognosis of Stage D2 prostate cancer (P = 0.0017). CONCLUSION: Results of this study indicate that MNV is prognostically superior to morphologic grading of malignancy, such as GS and WHO classification, in Stage D2 prostate cancer.

Adenocarcinoma↗
PubMed1995

Identification of a highly specific surface marker of T-cell acute lymphoblastic leukemia and neuroblastoma as a new member of the transmembrane 4 superfamily.

Five monoclonal antibodies detected a surface antigen expressed exclusively on T-cell acute lymphoblastic leukemia (T-ALL) in a panel of 45 human hematopoietic cell lines, including T-cell lines derived from adult T-cell leukemia and those established by immortalization with human T-cell leukemia virus type 1 or Herpesvirus saimiri. Peripheral blood mononuclear cells, including fresh and activated T cells, were also completely devoid of this antigen. We designated this antigen as TALLA-1 (from T-ALL-associated antigen 1). By expression cloning, a cDNA clone encoding TALLA-1 was isolated from T-ALL cell line Molt-4. TALLA-1 was found to be a member of the transmembrane 4 superfamily (TM4SF). The cDNA was also essentially identical to A15, which was isolated from another T-ALL cell line, HPB-ALL, by differential hybridization with normal peripheral blood lymphocytes, and to CCG-B7, which was isolated from a brain cDNA library using CCG repeat as a probe. The gene product was now characterized in detail at the protein level. Northern blot analysis showed that the gene was expressed most strongly in brain, skeletal muscle and spleen. In a panel of 52 non-hematopoietic human cell lines, the majority of neuroblastoma cell lines were found to be positive for TALLA-1. Like ME491, CO-029 and L6, TALLA-1 may be another TM4SF member behaving as a potential tumor-associated antigen.

Amino Acid Sequence↗
PubMed1995

Three-dimensional elution mapping of pyridylaminated N-linked neutral and sialyl oligosaccharides.

We propose a three-dimensional (3-D) sugar-mapping technique for pyridylaminated (PA) neutral and sialyl oligosaccharides as a powerful structural characterization of N-linked oligosaccharides using only picomoles of samples. The new map consists of the elution data from 42 different sialyl oligosaccharides, 26 of which are mono-, 7 of which are di-, 7 of which are tri-, and 2 of which are tetra-sialylated oligosaccharides. The 20 standard sialyl oligosaccharides were released from human serum and calf fetuin by digestion with glycoamidase A. The other 22 standard sialyl oligosaccharides were obtained by subsequent digestion of the above 20 sialyl oligosaccharides with beta-galactosidase, beta-N-acetylhexosaminidase, alpha-fucosidase, and alpha 2-->3 specific sialidase. The present 3-D mapping method involves the following four steps: First, a neutral and sialyl PA-oligosaccharide mixture is separated by HPLC on the diethylaminoethyl (DEAE) column according to the sialic acid content, and the elution data are considered as one of the three dimensions (Z-axis). Then, neutral, mono-, di-, tri-, and tetra-sialyl oligosaccharides are individually separated on the octadecylsilyl (ODS)-silica (X-axis) and amide-silica (Y-axis) columns. The fourth step is to plot the coordinates on a two-dimensional (2-D) map. Thus, for each of the groups separated on the DEAE column, a 2-D map can be achieved. By repeating the whole process for each group of different sialylation, the layers of the 2-D map lined up on the Z-axis form a 3-D map.(ABSTRACT TRUNCATED AT 250 WORDS)

Aminopyridines↗
PubMed1995

Locations of disulfide bonds and free cysteines in the heavy and light chains of recombinant human factor VIII (antihemophilic factor A).

The locations of disulfide bonds and free cysteines in the heavy and light chains of recombinant human factor VIII were determined by sequence analysis of fragments produced by chemical and enzymatic digestions. The A1 and A2 domains of the heavy chain and the A3 domain of the light chain contain one free cysteine and two disulfide bonds, whereas the C1 and C2 domains of the light chain have one disulfide bond and no free cysteine. The positions of these disulfide bonds are conserved in factor V and ceruloplasmin except that the second disulfide bond in the A3 domain is missing in both factor V and ceruloplasmin. The positions of the three free cysteines of factor VIII are the same as three of the four cysteines present in ceruloplasmin. However, the positions of the free cysteines in factor VIII and ceruloplasmin are not conserved in factor V.

Amino Acid Sequence↗
PubMed1995

Identification of the oligosaccharide structures of human coagulation factor X activation peptide at each glycosylation site.

Human blood coagulation factor X has two N-linked oligosaccharides at Asn39 and Asn49 residues and two O-linked oligosaccharides at Thr17 and Thr29 residues in the region of the factor X activation peptide (XAP) which is cleaved off during its activation by factor IXa. We determined the structure of oligosaccharides in the XAP region of human factor X. Four glycopeptides each containing a glycosylation site were isolated by digestion of XAP with endoproteinase Asp-N followed by reversed-phase HPLC. N-linked oligosaccharides released from the glycopeptides by glycoamidase A digestion were derivatized with 2-aminopyridine. Pyridylamino(PA)-oligosaccharides were separated by HPLC into neutral and sialyl oligosaccharides using an anion-exchange column. Structures of oligosaccharides and their contents at each glycosylation site were determined by a two-dimensional sugar mapping method. The contents of the neutral oligosaccharides at Asn39 and Asn49 residues were 32.5% and 30.0%, respectively. Six neutral and twelve monosialyl oligosaccharides isolated from both N-linked glycosylation sites showed similar elution profiles composed of bi-, tri- and tetra-antennary complex type oligosaccharides. The predominant component in neutral oligosaccharides was biantennary without a fucose residue. Two major monosialyl oligosaccharides were also biantennary without fucose and with a Neu5Ac alpha 2-->6 residue. In addition, the structures of O-linked oligosaccharides at Thr17 and Thr29 residues were suggested to be disialylated Gal beta 3GalNAc sequences by their component analyses.

Asparagine↗
PubMed1995

DNA-damaging potency and genotoxicity of aflatoxin M1 in somatic cells in vivo of Drosophila melanogaster.

Aflatoxin M1 (AFM1), a metabolic hydroxylation product of aflatoxin B1 (AFB1), and the parent compound were comparatively assayed for DNA-damaging potency and genotoxicity in vivo in Drosophila melanogaster using, respectively, the mei-9a mei-41D5 DNA repair test and the mwh/flr3 wing spot test. In the repair test, larval stock, consisting of meiotic recombination-deficient double mutant mei-9a mei-41D5 males and repair-proficient females, was exposed to the test agents, and the preferential killing of the mutant larvae was taken as evidence of the DNA-damaging effect. In this test, AFM1 was registered as a DNA-damaging agent with an activity approximately 3-fold lower than that of AFB1. In the wing spot test, where larval flies, trans-heterozygous for the somatic cell markers mwh and flr3, were treated and the wings were inspected at adulthood for spots manifesting the phenotypes of the markers, AFM1 exerted a genotoxic effect compatible to that of AFB1. Based on these results and other data, we predict that AFM1 may be genotoxic in mammalian in-vivo systems as well.

Aflatoxin B1↗