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Biomedical subjects

A Yamamoto

Publications and source records attributed to A Yamamoto.

At least 163 records · Page 9Linked to original sources
PubMed2001

Immunohistochemical study with antibody to glycoprotein GCDFP-15 for metastatic lung cancer from breast cancer.

Even when gross pathologic specimens are available, evaluation is always complicated due to the difficulty in distinguishing the pathologic diagnosis of an adenocarcinoma as a pulmonary metastasis of the breast or lung. In this paper, we describe the usefulness of a preoperative immunohistochemical study using gross cystic disease fluid protein-15 (GCDFP-15). A 50-year-old woman, who had undergone a right radical mastectomy due to an infiltrating ductal carcinoma 4 years previously, was admitted because of an abnormal shadow on chest roentgenography. A chest CT scan showed a nodule 20 mm in diameter with an irregular margin and vascular involvement in the S3 region of the right lung. Though the specimen from a percutaneous CT guided needle biopsy revealed characteristic pathologic findings of a primary lung adenocarcinoma under H.E. stain, which was recommended for lobar resection, we re-examined that specimen immunohistochemically, which disclosed that the tumor cells were negative for the antibody to pulmonary surfactant apoprotein and were positive for GCDFP-15 antibody. Therefore, the diagnosis of a metastatic breast carcinoma in the lung was established. Upon her request, a wedge resection of the right upper lobe including the tumor was performed under video-assisted thoracoscopic surgery (VATS). Her postoperative course was uneventful.

Apolipoproteins↗
PubMed2001

A quantitative in vitro assay for detecting biological activity of endotoxin using rabbit peripheral blood.

The pyrogen test or the endotoxin test has been playing a crucial role in detecting endotoxin in parenteral drugs. The current test methods, however, have disadvantages such as requiring a relatively high number of animals or an inadequacy in direct evaluation of in vivo activity. We made an attempt to establish a new in vitro assay method that can overcome the shortcomings of the current assay methods. We standardized the system of tumor necrosis factor-alpha (TNF-alpha) induction from the peripheral blood of rabbits for assaying endotoxin activity. This in vitro assay showed a linear dose-response regression between 0.1 and 5.0 endotoxin units per milliliter of endotoxin and a definite homogeneity of variance by logarithmically transforming the endotoxin and TNF-alpha concentrations in the reaction mixtures at 5 h of incubation at 37 degrees C. The assay showed a definite correlation with the pyrogen test but not with the endotoxin test when endotoxins from various bacteria were tested.

Animals↗
PubMed2001

Quality control of diphtheria tetanus acellular pertussis combined (DTaP) vaccines in Japan.

Diphtheria tetanus acellular pertussis combined (DTaP) vaccines have been successfully used in Japan by controlling their potencies and toxicities with animal models. In accordance with the recent practical introduction of DTaP vaccines of various formulations, a question has been raised in other nations as to the efficacy of a quality control system based on animal tests and standard preparations. The World Health Organization issued its guidelines on the production and quality control of acellular pertussis vaccines in 1998 along with the concept of quality control by ensuring that production lots were consistent with clinical trial lots, rather than by comparing them with standard preparations in traditional laboratory tests. However, because it is not feasible to evaluate the combined use of vaccines from different manufacturers in a clinical study, the alternative trend of quality control may give rise to a difficulty in rationalizing the practical immunizations to use vaccines of different brands in a mixed consequence. A standardized national regulation system to ensure the equivalence of approved products would be essential for such an immunization practice. The success of the Japanese DTaP vaccination suggests the possibility of an effective quality control of DTaP vaccines by means of standardized test systems.

Animals↗
PubMed2001

[Multiple cerebral tuberculomas presenting with paradoxical expansion: a case report].

A 24-year-old male presented with headache. He had been treated with antituberculous drugs for 19 months. MRI revealed 4 intracranial Gd-DTPA enhanced lesions surrounded by massive edema in the right frontal, both occipital and left basal ganglionic regions. Digital subtraction angiography showed no tumor stain. Two procedures for tumor resection were performed for the right frontal and left occipital regions, the latter of which definitively diagnosed by the polymerase chain reaction method. The tumors were well demarcated, showed a rough surface, and were elastically hard. The two residual lesions responded differently to chemotherapy. The lesion in the right occipital region decreased in size, while the other in the left basal ganglionic region continued to grow gradually 26 months after the antituberculous chemotherapy was started. According to previous reports, treatment should be continued for as long as 12-30 months in cases showing paradoxical expansion. In this case, the left basal ganglionic lesion began to decrease in size after 28 months of administration of anti-tuberculous drugs. We report successful treatment of a case of multiple tuberculomas presenting with paradoxical expansion managed by a combination of surgery and continuous chemotherapy.

Adult↗
PubMed2001

[Osteoporotic limb fractures].

Osteoporotic limb fractures often result in inadequate reduction, delayed bone union, and joint contracture with reduced patients' activity of daily living (ADL), since they usually occur at the metaphysis. To treat comminuted fractures in patients with severe osteoporosis is difficult. Intramedullary nail and external fixation are used for the treatment of those fractures. Recently calcium phosphate bone cement is available for the fracture treatment.

English Abstract↗
PubMed2000

Acidic endomembrane organelles are required for mouse postimplantation development.

Vacuolar-type H(+)-ATPase (V-ATPase) plays a major role in endomembrane and plasma membrane proton transport in eukaryotes. We found that the acidic compartments generated by V-ATPase are present from the one-cell stage of mouse preimplantation embryos. Upon differentiation of trophoblasts and the inner cell mass at the blastocyst stage, these compartments exhibited a polarized perinuclear distribution. PL16(-/-) embryos, lacking the V-ATPase 16-kDa proteolipid (c subunit), developed to the blastocyst stage and were implanted in the uterine epithelium, but died shortly thereafter. This mutant showed severe defects in development of the embryonic and extraembryonic tissues at a stage that coincided with rapid cell proliferation. When cultured in vitro, PL16(-/-) blastocysts could hatch and become attached to the surface of a culture dish, but the inner cell mass grew significantly slower and most cells failed to survive for more than 4 days. PL16(-/-) cells showed impaired endocytosis as well as organellar acidification. The Golgi complex became swollen and vacuolated, possibly due to the absence of the luminal acidic pH. These results clearly indicate that acidic compartments are essential for development after implantation.

Animals↗
PubMed2000

Drug release from w/o/w emulsions prepared with different chitosan salts and concomitant creaming up.

Water-in-oil-in-water (w/o/w) emulsions containing chitosan and tryptophan in the inner aqueous phase were prepared. The acids used to dissolve chitosan were formic, acetic, butyric and lactic acids. The effects of these organic acids and pH of the inner aqueous phase on the release of tryptophan and on the separation of the aqueous phase due mainly to creaming up during storage were studied. When the inner aqueous phase was an acidic chitosan solution, the release rate was almost the same irrespective of the acids mentioned above. When acetic and butyric acids were neutralized with sodium hydroxide, the release of tryptophan was prolonged. However, it was enhanced again by an excess amount of sodium hydroxide. On the other hand, the release was enhanced after neutralization of formic and lactic acids. Separation of the aqueous phase from the w/o/w emulsion during storage was remarkably delayed after neutralizing the chitosan solution containing acetic or butyric acids, while not so much in the cases of formic and lactic acids. It is concluded that these w/o/w emulsions were stabilized in the presence of neutralized chitosan gel suspensions containing acetate or butyrate ions in the inner aqueous phase.

Chitin↗
PubMed2000

A newly identified lipoprotein lipase (LPL) gene mutation (F270L) in a Japanese patient with familial LPL deficiency.

We have systematically investigated the molecular defects resulting in a primary lipoprotein lipase (LPL) deficiency in a Japanese male infant (proband SH) with fasting hyperchylomicronemia. Neither LPL activity nor immunoreactive LPL mass was detected in pre- or postheparin plasma from proband SH. DNA sequence analysis of the LPL gene of proband SH revealed homozygosity for a novel missense mutation of F270L (Phe(270)-->Leu/TTT(1065)-->TTG) in exon 6. The function of the mutant F270L LPL was determined by both biochemical and immunocytochemical studies. In vitro expression experiments on the mutant F270L LPL cDNA in COS-1 cells demonstrated that the mutant LPL protein was synthesized as a catalytically inactive form and its total amount was almost equal to that of the normal LPL. Moreover, the synthesized mutant LPL was non-releasable by heparin because the intracellular transport of the mutant LPL to the cell surface - by which normal LPL becomes heparin-releasable - was impaired due to the abnormal structure of the mutant LPL protein. These findings explain the failure to detect LPL activities and masses in pre- and postheparin plasma of the proband. The mutant F270L allele generated an XcmI restriction enzyme site in exon 6 of the LPL gene. The carrier status of F270L in the proband's family members was examined by digestion with XcmI. The proband was ascertained to be homozygous for the F270L mutation and his parents and sister were all heterozygous. The LPL activities and masses of the parents and the sister (carriers) were half or less than half of the control values. Regarding the phenotype of the carriers, the mother with a sign of hyperinsulinemia manifested hypertriglyceridemia (type IV hyperlipoproteinemia), whereas the healthy father and the sister were normolipidemic. Hyperinsulinemia may be a strong determinant of hypertriglyceridemia in subjects with heterozygous LPL deficiency.

Alleles↗
PubMed2000

Vacuolar H(+)-ATPase localized in plasma membranes of malaria parasite cells, Plasmodium falciparum, is involved in regional acidification of parasitized erythrocytes.

Recent biochemical studies involving 2',7'-bis-(2-carboxyethyl)-5, 6-carboxylfluorescein (BCECF)-labeled saponin-permeabilized and parasitized erythrocytes indicated that malaria parasite cells maintain the resting cytoplasmic pH at about 7.3, and treatment with vacuolar proton-pump inhibitors reduces the resting pH to 6.7, suggesting proton extrusion from the parasite cells via vacuolar H(+)-ATPase (Saliba, K. J., and Kirk, K. (1999) J. Biol. Chem. 274, 33213-33219). In the present study, we investigated the localization of vacuolar H(+)-ATPase in Plasmodium falciparum cells infecting erythrocytes. Antibodies against vacuolar H(+)-ATPase subunit A and B specifically immunostained the infecting parasite cells and recognized a single 67- and 55-kDa polypeptide, respectively. Immunoelectron microscopy indicated that the immunological counterpart of V-ATPase subunits A and B is localized at the plasma membrane, small clear vesicles, and food vacuoles, a lower extent being detected at the parasitophorus vacuolar membrane of the parasite cells. We measured the cytoplasmic pH of both infected erythrocytes and invading malaria parasite cells by microfluorimetry using BCECF fluorescence. It was found that a restricted area of the erythrocyte cytoplasm near a parasite cell is slightly acidic, being about pH 6.9. The pH increased to pH 7.3 upon the addition of either concanamycin B or bafilomycin A(1), specific inhibitors of vacuolar H(+)-ATPase. Simultaneously, the cytoplasmic pH of the infecting parasite cell decreased from pH 7.3 to 7.1. Neither vanadate at 0.5 mm, an inhibitor of P-type H(+)-ATPase, nor ethylisopropylamiloride at 0.2 mm, an inhibitor of Na(+)/H(+)-exchanger, affected the cytoplasmic pH of erythrocytes or infecting parasite cells. These results constitute direct evidence that plasma membrane vacuolar H(+)-ATPase is responsible for active extrusion of protons from the parasite cells.

Acids↗
PubMed2000

LC3, a mammalian homologue of yeast Apg8p, is localized in autophagosome membranes after processing.

Little is known about the protein constituents of autophagosome membranes in mammalian cells. Here we demonstrate that the rat microtubule-associated protein 1 light chain 3 (LC3), a homologue of Apg8p essential for autophagy in yeast, is associated to the autophagosome membranes after processing. Two forms of LC3, called LC3-I and -II, were produced post-translationally in various cells. LC3-I is cytosolic, whereas LC3-II is membrane bound. The autophagic vacuole fraction prepared from starved rat liver was enriched with LC3-II. Immunoelectron microscopy on LC3 revealed specific labelling of autophagosome membranes in addition to the cytoplasmic labelling. LC3-II was present both inside and outside of autophagosomes. Mutational analyses suggest that LC3-I is formed by the removal of the C-terminal 22 amino acids from newly synthesized LC3, followed by the conversion of a fraction of LC3-I into LC3-II. The amount of LC3-II is correlated with the extent of autophagosome formation. LC3-II is the first mammalian protein identified that specifically associates with autophagosome membranes.

Amino Acid Sequence↗
PubMed2000

Nonsteroidal anti-inflammatory drug-induced acute gastric injury in Helicobacter pylori gastritis in Mongolian gerbils.

We examined the acute ulcerogenic effects of indomethacin and N-(2, cyclohexyloxy-4-nitrophenyl)methane sulfonamide (NS-398) on the gastric mucosa in Helicobacter pylori-infected Mongolian gerbils. H. pylori infection for 4 and 12 weeks caused moderate and severe gastritis, respectively, with cyclooxygenase-2 expression and an increase in prostaglandin E(2) production. In normal animals, gastric injury was caused by indomethacin, but not by NS-398. At 4 weeks infection, gastric lesions were synergistically aggravated by indomethacin, and NS-398 at high doses. However, at 12 weeks, the synergistic effects of indomethacin and NS-398 with H. pylori were not observed. Indomethacin and NS-398 at high doses inhibited prostaglandin E(2) production in both normal and the infected mucosa. NS-398 at low dose reduced only the H. pylori-increased prostaglandin production. These results suggest that nonsteroidal anti-inflammatory drugs (NSAIDs) synergistically aggravate gastric lesions in moderate H. pylori gastritis, but not in severe gastritis. Cyclooxygenase-2 inhibition only might not induce acute gastric injury in H. pylori gastritis.

Acute Disease↗
PubMed2000

CO2 permeability and bicarbonate transport in microperfused interlobular ducts isolated from guinea-pig pancreas.

Permeabilities of the luminal and basolateral membranes of pancreatic duct cells to CO2 and HCO3- were examined in interlobular duct segments isolated from guinea-pig pancreas. Intracellular pH (pHi) was measured by microfluorometry in unstimulated, microperfused ducts loaded with the pH-sensitive fluoroprobe 2'7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF). When HCO3-/CO2 was admitted to the bath, pHi decreased transiently as a result of CO2 diffusion and then increased to a higher value as a result of HCO3- uptake across the basolateral membrane by Na+-HCO3- cotransport. When HCO3-/CO2 was admitted to the lumen, pHi again decreased but no subsequent increase was observed, indicating that the luminal membrane was permeable to CO2 but did not allow HCO3- entry to the cells from the lumen. Only when the luminal HCO3- concentration was raised above 125 mM was HCO3- entry detected. The same was true of duct cells stimulated with forskolin. Recovery of pHi from an acid load, induced by exposure to an NH4+ pulse, was dependent on basolateral but not luminal Na+ and could be blocked by basolateral application of methylisobutylamiloride and H2DIDS. This indicates that the Na+-H+ exchangers and Na+-HCO3- cotransporters are located exclusively at the basolateral membrane. In the presence of HCO3-/CO2, substitution of basolateral Cl- with glucuronate caused larger increases in pHi than substitution of luminal Cl-. This suggests that the anion exchanger activity in the basolateral membrane is greater than that in the luminal membrane. We conclude that the luminal and basolateral membranes are both freely permeable to CO2, but while the basolateral membrane has both uptake and efflux pathways for HCO3-, the luminal membrane presents a significant barrier to the re-entry of secreted HCO3-, largely through the inhibition of the luminal anion exchanger by high luminal HCO3- concentrations.

Animals↗
PubMed2000

Requirement for Phe36 for DNA binding and mismatch repair by Escherichia coli MutS protein.

The MutS family of DNA repair proteins recognizes base pair mismatches and insertion/deletion mismatches and targets them for repair in a strand-specific manner. Photocrosslinking and mutational studies previously identified a highly conserved Phe residue at the N-terminus of Thermus aquaticus MutS protein that is critical for mismatch recognition in vitro. Here, a mutant Escherichia coli MutS protein harboring a substitution of Ala for the corresponding Phe36 residue is assessed for proficiency in mismatch repair in vivo and DNA binding and ATP hydrolysis in vitro. The F36A protein is unable to restore mismatch repair proficiency to a mutS strain as judged by mutation to rifampicin or reversion of a specific point mutation in lacZ. The F36A protein is also severely deficient for binding to heteroduplexes containing an unpaired thymidine or a G:T mismatch although its intrinsic ATPase activity and subunit oligomerization are very similar to that of the wild-type MutS protein. Thus, the F36A mutation appears to confer a defect specific for recognition of insertion/deletion and base pair mismatches.

Adenosine Triphosphatases↗