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Biomedical subjects

K Aoki

Publications and source records attributed to K Aoki.

At least 361 records · Page 20Linked to original sources
PubMed1996

Travelling Wave Solutions for the Spread of Farmers into a Region Occupied by Hunter-Gatherers

The geographical spread of an initially localized population of farmers into a region occupied by hunter-gatherers is modelled as a reaction-diffusion process in an infinite linear habitat. Hunter-gatherers who come in contact with farmers are converted at rate e. Growth of initial farmers, converted farmers, and hunter-gatherers is logistic with intrinsic rates rf, rc, and r h. The carrying capacities of all farmers (i.e., initial and converted farmers combined) and hunter-gatherers are K and L. Individuals migrate at random, where the diffusion constant, D, is the same for all three groups. Under the above assumptions, we deduce the conditions under which wavefronts of initial or converted farmers are generated. Numerical work suggests that a travelling wave solution of constant shape always exists, comprising an advancing wavefront of all farmers and a retreating wavefront of hunter-gatherers. Linear analysis in phase space suggests that the speed is given by 2(Drf)1/2 or 2[D(r c+eL)]1/2, whichever is greater. The composition of the expanding distribution of all farmers appears to depend on the relative magnitude of rf versus rc+eL and of eK versus rh. A wavefront of initial farmers is not generated if rf rh. On the other hand, a wavefront of initial farmers is generated if rf>rc+eL. In this case, the waveform is peaked with leading and trailing edges that converge to 0 if eK rh so that there is substantial displacement of the indigenous hunter-gatherers by the initial farmers.

Journal Article↗
PubMed1996

Synchronous lymphoma and adenocarcinoma occurring as a collision tumor in the stomach: report of a case.

We report herein the rare case of a 71-year-old man who was initially operated on under the diagnosis of advanced gastric cancer, but was subsequently found to have synchronous lymphoma and early adenocarcinoma of the stomach, confirmed by postoperative pathological examination. The patient had a history of lymphoma of the left tonsil, and histologically the gastric lymphoma was observed to be of the non-Hodgkin's, diffuse, large-cell type. Conversely, the gastric cancer was early well-differentiated tubular adenocarcinoma of type 0-IIa, according to the Japan Gastroenterological Endoscopy Society classification. The two tumors had collided at the fornix. The relationship between these two tumors is analyzed and the most appropriate methods of diagnosis and treatment are discussed.

Adenocarcinoma↗
PubMed1996

Syringohydromyelia in Hajdu-Cheney syndrome.

We report the case of a 10-year-old boy with typical manifestation of Hajdu-Cheney syndrome. MRI demonstrated syringohydromyelia involving almost the entire spinal cord, although neurological symptoms had not yet developed. Syringohydromyelia is considered to be a sequel to progressive basilar invagination and is one of the essential features of this rare osteolytic bone dysplasia.

Brain Diseases↗
PubMed1996

Differential sensitivity of two related viruses, Newcastle disease virus and Sendai virus, to interferon in mouse Had-2 cells: selective inhibition of translation of NDV mRNA.

Had-2, a mouse mutant cell line derived from FM3A, constitutively releases interferon-alpha and beta and acquires resistance to Newcastle disease virus (NDV) and other viruses. However, Had-2 was found as susceptible to Sendai virus (HVJ) as FM3A. Even when Had-2 cells were infected simultaneously with NDV and HVJ, only the replication of NDV was inhibited, while that of HVJ was not. Northern blot hybridization analysis indicated that accumulation of NDV-specific primary transcripts was somewhat reduced in Had-2, but the reduction was insufficient to critically suppress the viral replication. Moreover, this decrease was not observed in the presence of cycloheximide, and a closely comparable amount of the primary transcripts was detected in both Had-2 and FM3A cells. The mRNA accumulated in the presence of cycloheximide was translated efficiently on removal of the inhibitor in FM3A cells, but not at all in Had-2 cells. Thus the translation of NDV mRNA was the major target of interferon in Had-2 cells. The fact that the synthesis of HVJ proteins was unaffected in Had-2 cells may imply that a host-cell component that distinguishes between NDV and HVJ mRNAs is involved in their translation.

Animals↗
PubMed1996

Fragile bone syndrome associated with craniognathic fibro-osseous lesions and abnormal modeling of the tubular bones: report of two cases and review of the literature.

OBJECTIVE: To report examples of disorders characterized by bone fragility, calvarial and/or gnathic fibro-osseous lesions, and metadiaphyseal undermodeling of the tubular bones. DESIGN: The clinical, radiological, and pathological features of two patients are described and the literature reviewed. PATIENTS: The patients comprised a 10-year-old boy and a 48-year-old woman. The former exhibited multiple fractures starting in early childhood and calvarial masses which developed in late childhood; the latter showed a mandibular mass. RESULTS: Calvarial doughnut lesions, osteopenia with coarse bony trabeculae, and undermodeling of the lower limbs were radiologically demonstrated in the first patient, while multiple sclerotic foci in the maxilla and mandible, spontaneous bowing of the right femur, and minimal undermodeling of the tibiae were demonstrated in the second. Bone biopsy of the iliac crest in the first patient revealed histologically normal bony trabeculae. Bone histomorphometry suggested an increased osteoid surface. Osteoid volume was also slightly increased. The pathological findings of the mass in the jaw in the latter patient were consistent with it being a fibro-osseous lesion. The literature review revealed several patients whose features overlapped with those of our patients. CONCLUSION: These patients may represent a group of fragile bone syndromes which differ from osteogenesis imperfecta.

Bone Diseases, Developmental↗
PubMed1996

Disaggregation of polyribosomes in the spinal anterior horn cells in a patient with X-linked spinal and bulbar muscular atrophy.

The spinal anterior horn cells (AHCs) in a patient with X-linked spinal and bulbar muscular atrophy (SBMA) were examined by light and electron microscopy, giving special attention to alterations in the rough endoplasmic reticulum (ER). Seven age-matched subjects were used as controls. The patient with SBMA showed a severe decrease of AHCs, but the Nissl substance in the remaining AHCs appeared well preserved on light microscopy. Electron microscopy revealed a relatively well preserved parallel lamellar pattern of ER and marked disaggregation of the polyribosomes surrounding the ER in the remaining AHCs. These findings indicate that the Nissl substance was affected in spite of its light microscopic appearance in SBMA, and that the AHCs degenerate through disaggregation of the polyribosomes of the ER.

Anterior Horn Cells↗
PubMed1996

Detection of enterovirus 70 by polymerase chain reaction in acute hemorrhagic conjunctivitis.

PURPOSE: We have developed and applied reverse transcription-polymerase chain reaction for the detection of enterovirus 70 from conjunctival swabs of patients among the population of an acute hemorrhagic conjunctivitis epidemic on Okinawa, Japan, in 1994. METHODS: The primers used were selected from the VP1, VP2, and VP3 regions of the enterovirus 70 nucleotide sequence. RESULTS: Twelve of 27 culture-negative specimens were positive by reverse transcription-polymerase chain reaction. CONCLUSIONS: The reverse transcription-polymerase chain reaction test provides a reliable diagnostic method that readily allows specific detection of enterovirus 70 in patients with acute hemorrhagic conjunctivitis in whom low enterovirus 70 recovery rates have been obtained recently by cell culture.

Conjunctiva↗
PubMed1996

Differential scanning calorimetric studies on bovine serum albumin. IV. Effect of anionic surfactants with various lengths of hydrocarbon chain.

Using defatted and SH-blocked bovine serum albumin (BSA), measurements of differential scanning calorimetry (DSC) have been made at pH 7 on the complexes of BSA and a series of sodium alkyl sulfates used were sodium decyl sulfate (SDeS), sodium octyl sulfate (SOS), sodium hexyl sulfate (SHS) and sodium ethyl sulfate (SES). Results obtained were compared with those on the system BSA-sodium dodecyl sulfate (SDS) studied previously. Two peaks P1 and P2 existed in the DSC curve of BSA. These peaks originate in the heat-induced transition of BSA. The pattern of DSC curve changed with the amount of the ligand added, i.e. with the molar mixing ratio ligand/BSA (1). The change for systems BSA-SDeS, BSA-SOS and BSA-SHS was qualitatively the same as that for the system BSA-SDS (2). Interestingly, SES, which is not a surfactant, interacts with BSA. The change for the system BSA-SES was qualitatively the same as that for the system BSA-Na2SO4. All alkyl sulfates suppressed the heat-induced transition at lower concentrations. A linear relationship was obtained for the plots of log(D/A)1 versus log CMC, where (D/A)1 is the molar mixing ratio of anionic surfactant (D) to BSA (A) at which the most heat-stable complex is formed. This suggests that the hydrophobic force has a serious effect on the formation of heat-stable complexes.

Anions↗
PubMed1996

Detection of UDP-D-xylose: alpha-D-xyloside alpha 1-->3xylosyltransferase activity in human hepatoma cell line HepG2.

We previously reported the detection of novel O-linked sugar chains classified as being of the glucosyl-O-serine type [Hase et al. (1988) J. Biochem. 104, 867-868]. The sugar chains are a disaccharide (Xyl alpha 1-3Glc) and a trisaccharide (Xyl alpha 1-3Xyl alpha 1-3 Glc) linked to serine residues in epidermal growth factor-like domains of human and bovine blood coagulation factors. The structures of these sugar chains suggested the presence of an alpha 1-->3xylosyltransferase for their biosynthesis. We report here on the detection of alpha 1-->3xylosyltransferase activity which catalyzes the transfer of xylose to Xyl alpha 1-3Glc in the human hepatoma cell line HepG2. We employed pyridylaminated Xyl alpha 1-3Glc as a fluorescent acceptor and UDP-D-Xyl as a donor. The reaction product was purified by reversed-phase HPLC, and the structure of the transfer product isolated was confirmed to be pyridylaminated Xyl alpha 1-3Xyl alpha 1-3Glc by Smith degradation, mass spectrometry, and alpha- and beta-xylosidase digestions. The apparent K(m) value for pyridylaminated Xyl alpha 1-3Glc was 52 mM and for UDP-D-Xyl 0.28 mM. Optimum pH was 7.2. The enzyme was inactivated by addition of EDTA, and its activity was restored by addition of Mn2+ and Mg2+. These results indicate the presence of a novel enzyme which is able to transfer xylose to Xyl alpha 1-3Glc, forming Xyl alpha 1-3Xyl alpha 1-3Glc in human cells.

Animals↗
PubMed1996

Prognostic factors in patients with advanced pancreatic cancer treated with systemic chemotherapy.

The clinical features of 65 patients with advanced pancreatic cancer treated between 1984 and 1993 were analyzed retrospectively to identify the significant prognostic factors. All the patients had presented unresectable or metastatic disease on imaging diagnostic evaluation and had received systemic chemotherapy. The overall median survival time and 1-year survival rate were 3.9 months and 9.8%, respectively. The independent favorable prognostic factors identified by multivariate analysis using the Cox proportional hazards model were a performance status of 0-1, a serum carcinoembryonic antigen level of < 10 ng/ml, and an absence of distant metastasis. A prognostic index calculated from the regression coefficients for these three factors was used to classify the patients into three groups, with good, intermediate, and poor prognoses. The median survival time for these three groups was 7.4, 3.5, and 2.0 months, respectively (p < 0.001). The results of this study may be useful in the design and analysis of future clinical trials of systemic chemotherapy for advanced pancreatic cancer.

Adult↗
PubMed1996

Temporal and spatial distribution of ferredoxin isoproteins in tomato fruit.

Five ferredoxin (Fd) isoproteins (FdA, FdB, FdC, FdD, and FdE) were isolated from tomato (Lycopersicon esculentum cv Momotaro) fruit. These isoproteins showed differential temporal and spatial accumulation patterns. FdA and FdC were present in leaves. FdE was present in roots, and FdB and FdD were fruit-specific. During fruit growth, the relative abundance of FdA decreased and that of FdE increased. The FdE/FdA ratio was higher in the inner tissues of the fruit than in the outer tissue, and it was correlated with starch accumulation. In darkgrown fruit the contents of FdA, FdB, and FdC, as well as chlorophyll, decreased remarkably relative to their light-grown counterparts; however, the contents of FdE and starch did not change significantly. Under in vitro conditions FdE showed higher cytochrome c reduction activity than FdA and FdB. These results, together with their N-terminal sequences, indicate that both photosynthetic- and heterotrophic-type Fd isoproteins are present in tomato fruit.

Amino Acid Sequence↗
PubMed1996

Humoral hypercalcemia of malignancy with elevated plasma PTHrP, TNF alpha and IL-6 in cutaneous squamous cell carcinoma.

A case of humoral hypercalcemia of malignancy in cutaneous squamous cell carcinoma is reported. An 82-year-old male underwent surgery for cutaneous squamous cell carcinoma (SCC) of the left hand in 1992. He subsequently developed clouding of consciousness with remarkable hypercalcemia, a high parathyroid hormone related protein (PTHrP) level, and elevated plasma cytokine levels [tumor necrosis factor alpha (TNF alpha), interleukin-6 (IL-6)]. Diagnosis of humoral hypercalcemia of malignancy (HHM) was made on the basis of these findings. He died of renal insufficiency due to this hypercalcemia in spite of several replacement therapies and chemotherapies. The PTHrP might have derived from the SCC and have been responsible for the HHM in conjunction with IL-6 and TNF alpha.

Aged↗
PubMed1996

Clinico-epidemiological features of infantile hydrocephalus in Japan.

In 1988, a nationwide survey was conducted in Japan, in order to examine the prevalence and clinico-epidemiological features of hydrocephalus that developed before 1 year of age. The study was based on questionnaires that were sent to all hospitals in Japan with more than 200 beds. There were 1435 patients who were eligible for the analysis. They were born before 1987 and diagnosed as having infantile hydrocephalus. Approximately two-thirds of the patients had primary hydrocephalus. Neural tube defects were the most frequent cause of the primary hydrocephalus and common among full-term infants. On the other hand, secondary hydrocephalus occurred more often in preterm infants, mainly following intracranial hemorrhage. Intracranial hemorrhage as a cause of hydrocephalus increased over the year, while the incidence of hydrocephalus secondary to intracranial infection decreased during the same period.

Brain↗
PubMed1996

Human pregnancy serum suppresses the proliferative response of lymphocytes to autologous PHA-activated T lymphoblasts.

PROBLEM: We have previously demonstrated that human serum can suppress the proliferative response in autologous mixed lymphocyte reaction (AMLR) in which phytohemagglutinin (PHA)-activated T lymphoblasts act as stimulators (T-TPHA AMLR). The aim of the present work was to determine whether pregnancy serum (PS) possesses an inhibitory capacity similar or different in magnitude. METHODS: Sixteen PS were added to T-TPHA AMLR cultures and the proliferative response was compared with that in the presence of human serum. The effect of PS on the IL-2 dependent proliferation of PHA-activated T Lymphoblasts was examined as well. RESULTS: PS induced a significantly more pronounced suppression of T-TPHA AMLR than human serum (P < 0.05). One PS tested was not inhibitory but rather stimulatory. This PS was obtained from a woman who subsequently had IUGR. The inhibition is related to the existence of a serum inhibitory factor and not to the lack of a serum supporting factor. PS inhibited not only T-TPHA AMLR of the same woman but also T-TPHA AMLR of other individuals as well, implying that the inhibitor is a non-MHC restricted factor. IL-2 dependent cell proliferation was not inhibited by PS, implying that the inhibitor detected in T-TPHA AMLR is not a general cell proliferation inhibitor. CONCLUSIONS: These results suggest that a non-MHC restricted inhibitory factor present in PS may play an important biological role in regulating local immune responses in the fetal-placental unit mediated by autoreactive T cells restricted to autologous activated T lymphocytes.

Antilymphocyte Serum↗