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Biomedical subjects

H Maki

Publications and source records attributed to H Maki.

At least 37 records · Page 2Linked to original sources
PubMed1998

Anticancer efficacy in vivo and in vitro, synergy with 5-fluorouracil, and safety of recombinant methioninase.

The elevated exogenous-methionine dependency of tumors for growth has been observed in all major cancer cell types. We have previously cloned a methioninase (rMETase) from Pseudomonas putida to deplete methionine. Growth inhibition followed by apoptotic cell death was induced by treatment of tumor cells with rMETase in vitro. A single i.p. injection of 300 units of rMETase can lower the serum methionine level in the mice from 70 microM to less than 1 microM within 2 h and maintain this depleted level for 8 h. Repeated dosing of rMETase of tumor-bearing mice could be administered without acute immune-hypersensitivity. rMETase treatment demonstrated growth inhibitory activity against human tumors in nude mice, including those which were multiple drug-resistant. No body weight loss or hematotoxicity, except a slight anemia, was found throughout the therapy. The combined treatment of the Lewis lung carcinoma with a fixed rMETase dose and increasing doses of 5-fluorouracil (5-FU) resulted in a dose-dependent enhanced antitumor efficacy for survival as well as tumor growth inhibition. Thus, methionine depletion by rMETase potentiates the antitumor efficacy of 5-FU. The data presented in this report thus indicate that rMETase is active alone, is synergistic in combination with 5-FU, and has negligible toxicity suggesting a novel clinical approach for effective cancer therapy.

Animals↗
PubMed1998

Ascorbate-dependent enhancement of nitric oxide formation in activated macrophages.

Macrophages activated with bacterial lipopolysaccharide (LPS) and cytokines produce nitric oxide through the induction of iNOS gene expression. Ascorbate increased NOx (nitrite and nitrate) formation by approximately 40% in a mouse macrophage-like cell line, J774.1, activated with LPS and interferon-gamma. Ascorbate alone exhibited no inductive activity toward NO formation. N(G)-Monomethyl-L-arginine inhibited nitrite formation in cells activated in the presence or absence of ascorbate. Northern and Western blotting analyses showed that both iNOS mRNA and protein steady-state levels were increased approximately twofold in cells activated in the presence of ascorbate compared to in cells activated only with the inducers. These data suggest that ascorbate increased NO production by increasing the amount of iNOS in the activated macrophages.

Animals↗
PubMed1998

Replantation of the great toe: two case reports.

We performed two replantations of the great toe in children less than 4 years of age. Both cases were successful, and there was no complaint of pain or disturbance in gait, postoperatively. Good results seemed to be based on mobility of the metatarsophalangeal joint and on sensation in the replanted toe. In our opinion, all traumatic amputations of the great toe in children should be replanted, if the conditions of the foot and amputated toe allow vascular and neural reattachment.

Amputation, Traumatic↗
PubMed1997

Plant 21D7 protein, a nuclear antigen associated with cell division, is a component of the 26S proteasome.

Previously, we cloned a carrot (Daucus carota L.) cDNA encoding a 45-kD protein, 21D7, located in the nuclei of proliferating cells. The 21D7 protein is similar to the partial sequence of a regulatory subunit of the bovine 26S proteasome, p58 (G. DeMartino, C.R. Moomaw, O.P. Zagnitko, R.J. Proske, M. Chu-Ping, S.J. Afendis, J.C. Swaffield, C.A. Slaughter [1994] J Biol Chem 269: 20878-20884) and to the deduced sequence encoded by the Saccharomyces cerevisiae gene SUN2 (M. Kawamura, K. Kominami, J. Takeuchi, A. Toh-e [1996] Mol Gen Genet 251: [146-152]). In our work, the expression of plant 21D7 cDNA rescued the yeast sun2 mutant. Fractionation of carrot and spinach (Spinacia oleracea L.) crude extracts showed that the 21D7 protein sedimented with the active 26S proteasomes. The cessation of cell proliferation in carrot suspensions at the stationary phase caused 26S proteasome dissociation and, correspondingly, the 21D7 protein sedimented together with the free regulatory complexes of the 26s proteasomes. Large-scale purification of carrot 26s proteasomes resulted in co-isolation of the 21D7 protein. Polyacrylamide gel electrophoresis under nondenaturing conditions showed that the 21D7 protein had the same mobility as the 26S proteasome and that proteasome dissociation changed the mobility of the 21D7 protein accordingly. We conclude that the 21D7 protein is a subunit of the plant 26S proteasome and that it probably belongs to the proteasome regulatory complex.

Animals↗
PubMed1997

Formation of potent hybrid promoters of the mutant llm gene by IS256 transposition in methicillin-resistant Staphylococcus aureus.

From high-level methicillin-resistant Staphylococcus aureus SRM551, the low-level heterogeneously resistant mutant, SRM563, was isolated by transposon mutagenesis. The transposon insertion occurred in the 3' region of the llm gene in the mutant (H. Maki, T. Yamaguchi, and K. Murakami, J. Bacteriol. 176:4993-5000, 1994). Resistant revertants were generated from the mutant strain SRM563 on the plate containing methicillin at a concentration of 12.5 microg/ml or more. In some revertants, the insertion sequence IS256 was observed to be transposed into one of five sites localized 88 to 212 bp upstream of the mutant llm at a frequency of 2.8 x 10(-7) in the bacterial population. The IS256 transposition created a new hybrid promoter in which the -35 region at the end of IS256 was properly arranged in relation to the -10-like sequence upstream of llm. The new promoters greatly enhanced the transcription of the mutant llm, as judged by blotting analysis of llm mRNA, with concomitant elevation of the methicillin resistance. Involvement of the insertion sequence in the heteroresistance characteristics of methicillin-resistant S. aureus was suggested.

Bacterial Proteins↗
PubMed1996

Evidence for a promoter-like activity in the short non-coding region of human papillomaviruses.

A short non-coding region (SNR) commonly exists between the E5 and L2 open reading frames of human papillomaviruses (HPVs). Except for the poly(A) signal for early gene transcripts, no biological functions have been discovered for the SNR. To test a possible promoter-like activity of the SNR, we carried out CAT reporter assays using constructs containing the SNRs from HPV-16, -18 and -33 linked to a promoterless CAT gene. We reproducibly observed enhanced expression of CAT gene by the SNRs. Co-expression of a transcriptional activator (LAP/NF-IL6) or deletion of the poly(A) signal augmented the promoter-like activity of the SNRs. RNase protection assays revealed a LAP-inducible CAT mRNA properly initiated from the HPV-16 SNR. These results may suggest that the SNR has a promoter activity that is regulated by keratinocyte differentiation.

Base Sequence↗
PubMed1996

Apoptosis involved in density-dependent regulation of rat fibroblastic 3Y1 cell culture.

When rat 3Y1 fibroblastic cells are cultured toward confluency, the cells go through maximum cell density (overshoot) before reaching post-confluence stationary cell density. After overshooting, a number of floating cells are found in the medium. In a long-term culture, a cyclic change in cell number, an increase after each medium refreshment and subsequent cell loss within a few days has been observed so that the cell populations in the monolayer maintain post-confluence stationary cell density at a constant level. The floating cells excluded trypan blue, but they had no ability to attach to the substrate and to form colonies after being reseeded in fresh medium. They had condensed and uniformly electron-dense chromatin with sharply circumscribed edges. Their DNA contained a laddering pattern in harmony with internucleosomal cleavage. The features were those of apoptosis. When floating cells appeared, apoptotic bodies were also observed in the monolayer. Most of them were found within the cytoplasm of intact cells, suggesting that apoptotic bodies were also faded away from the culture by being rapidly engulfed by neighboring intact cells. These suggest that apoptosis and subsequent detachment from the monolayer or engulfment by neighboring intact cells, in addition to inhibition of cell division, are basic mechanisms on the process of density-dependent regulation in monolayer culture of rat 3Y1 cells.

Animals↗
PubMed1995

High gene expression in Escherichia coli of recombinant alginate lyase as a fused protein with beta-galactosidase alpha-peptide.

Escherichia coli LE392 (pAL28) was previously isolated as a positive clone harboring the alginate lyase gene (aly) from an alginate-degrading strain, Pseudomonas sp. OS-ALG-9. The plasmid pAL205, one of the constructs obtained after successive subcloning of pAL28, gave the highest expression of aly in E. coli cells. A 8-fold increase in the alginate lyase (Aly) activity in E. coli JM109 (pAL205) was induced with isopropyl-beta-D-thiogalactoside, which was 210 times higher than that in E. coli LE392 (pAL28). The highly significant increase in the expression of the Aly enzyme with pAL205 was investigated through the nucleotide sequence around the 5' region of aly as well as the N-terminal sequence of the purified enzyme. It was found that the Aly expressed in E. coli (pAL205) was a fused protein containing 7 residues from the N-terminus of beta-galactosidase alpha-peptide and the mature protein found in the Pseudomonas sp. except for three residues in the N-terminal.

Alginates↗
PubMed1995

Purification and characterization of the recombinant alginate lyase from Pseudomonas sp. leaked by Escherichia coli upon addition of glycine.

The plasmid pAL205 encodes an alginate lyase gene of Pseudomonas sp. OS-ALG-9, fused in frame to the beta-galactosidase alpha-peptide gene. The alginate lyase (Aly) expressed in Escherichia coli (pAL205) was significantly secreted into the medium by the addition of glycine. The extracellular enzyme isolated from the culture of E. coli JM109 (pAL205) was purified over 15,000-fold by successive chromatography and subjected to amino acid sequence analysis. The sequence determined was identical to that of the intracellular protein. Since the activity and molecular size of the extracellular Aly is identical to the intracellular protein and to the Aly isolated from Pseudomonas, the glycine does not affect or modify the Aly during its leakage into the medium.

Alginates↗
PubMed1995

Functional cooperation of MutT, MutM and MutY proteins in preventing mutations caused by spontaneous oxidation of guanine nucleotide in Escherichia coli.

8-Oxo-dGTP (8-oxo-7,8-dihydrodeoxyguanosine triphosphate) is a potent mutagenic substrate for DNA synthesis. The accumulation of 8-oxo-dGTP in the nucleotide pool induces G:C-->T:A transversion as well as A:T-->C:G transversion, and Escherichia coli cells possess mechanisms for preventing such mutations. The mutT gene product specifically hydrolyzes 8-oxo-dGTP to the monophosphate form while the mutM and the mutY gene products function to correct mispairs caused by incorporation of 8-oxoguanine into DNA. From analyses of forward mutations induced in cells lacking 8-oxo-dGTPase (MutT protein) and/or repair enzymes that suppress mutations caused by 8-oxoguanine in DNA (MutM and MutY proteins), cooperative functions of these proteins in control of the spontaneous mutagenesis became evident. In mutator strains lacking MutT and/or MutM proteins, 8-oxoguanine of DNA increased to a concentration expected from the increased rate of mutation.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1995

[Pulmonary endometriosis with recurrent catamenial hemoptysis].

A 32-year-old woman with a history of dilation and curettage for missed abortion at 31 years old had sudden hemoptysis during menstruation on May 25, 1993. She had catamenial hemoptysis again, and was admitted to our hospital on July 21, 1993. After admission, catamenial hemoptysis occurred, and a nodular shadow was noted in the right S4 area on chest roentgenogram and computed tomogram. A few days after menstruation, hemoptysis and the abnormal shadow on chest roentgenogram disappeared. Pulmonary endometriosis was diagnosed by clinical course, past history, and chest roentgenographic findings. During the next menstruation, hemoptysis and a nodular shadow in the right S4 area on chest roentgenogram recurred, so transbronchial lung biopsy and laparoscopy were done. TBLB specimens revealed macrophages with phagocytosed hemosiderin, and laparoscopy revealed pelvic endometriosis. She was treated with buserelin acetate. Catamenial hemoptysis and the nodular shadow on the chest roentgenogram disappeared after treatment.

Adult↗
PubMed1995

[Simultaneous production of parathyroid hormone-related protein (PTHrP) and granulocyte colony-stimulating factor (G-CSF) in lung cancer patients with hypercalcemia and leukocytosis].

Hypercalcemia and leukocytosis are often associated with primary lung cancer as a paraneoplastic syndrome. Recently, parathyroid hormone-related protein (PTHrP) and granulocyte colony stimulating factor (G-CSF) have been identified as major causative peptides for hypercalcemia and leukocytosis, respectively. We studied four men with advanced primary lung cancer (stages from IIIA to IV) who presented with hypercalcemia (corrected serum calcium levels: 10.5 mg/dl) and leukocytosis (WBC > 10,000 per mm3). The age of the patients ranged from 59 to 79 years old. The pathological subtypes were squamous cell carcinoma in three and adenocarcinoma in one. The mean serum calcium levels and leukocyte counts were 15.8 +/- 1.4 mg/dl (mean +/- SE) and 24,800 +/- 3,253 cells/mm3 (mean +/- SE), respectively. Abnormally high serum levels of PTHrP and G-CSF were found in three patients (mean +/- SE: 137 +/- 68 pg/ml; normal range in human serum, < 16 pg/ml), and in all four (mean +/- SE: 72 +/- 7.7 pg/ml; normal range in human serum, < 20 pg/ml), respectively. Immuno-histochemical examination of cancerous tissue obtained from these patients showed positive staining for both PTHrP and G-CSF within the cytoplasm of all the cancerous tissue. These results suggest that the association of hypercalcemia and leukocytosis in patients with advanced primary lung cancer is caused by production of both PTHrP and G-CSF by cancerous tissue.

Aged↗