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Biomedical subjects

M Hamada

Publications and source records attributed to M Hamada.

At least 433 records · Page 24Linked to original sources
PubMed1989

Vascular pedicle transposition of an ovary with subsequent intrauterine pregnancy.

In a patient who underwent both a right salpingectomy because of right tubal pregnancy and left ovarian cystectomy due to an ovarian cyst, we performed an operation whereupon the normal right ovary was shifted toward the position of the left ovary together with the pelvic infundibular ligament. By observation of the ovarian follicle through ultrasonic tomography, the follicle, as seen only from the right preoperatively, was seen only from the left after the operation. The patient delivered a baby by normal pregnancy 3 months after the operation. This method requires no complicated technique and could prove to be a promising therapeutic procedure treating patients with infertility.

Adult↗
PubMed1989

Synthetic genes for human muscle-type adenylate kinase in Escherichia coli.

An artificial gene coding for the human muscle-type cytosolic adenylate kinase (hAK1) was chemically synthesized and directly expressed in Escherichia coli under the control of trp promoter. The DNA duplex of 596 bp was designed and constructed from 40 oligonucleotide fragments of typically 30 nucleotides in length. Twelve unique restriction sites were fairly evenly spaced in the synthetic gene to facilitate site-specific mutagenesis at any part of this recombinant protein. The genes for mutant hAK1 (Tyr 95----Phe 95, Y95F hAK1; Arg 97----Ala 97, R97A hAK1) were constructed by cassette mutagenesis and utilized restriction sites incorporated in the hAK1 gene. The recombinant hAK1 was purified to homogeneity by a two-step chromatographic procedure with a good yield, and showed the same adenylate kinase activity as that of authentic hAK1. Preliminary kinetic studies show that the enzymatic activity (Vmax app,cor/Et) of Y95F hAK1 was slightly greater than that of recombinant hAK1, whereas R97A hAK1 still possessed approximately 4% of recombinant hAK1 activity. These results suggest that the Arg-97 residue is important but not essential for catalytic activity, and that Tyr-95 can be replaced by phenylalanine without substantial effects on the enzymatic activity. Moreover, preliminary estimates of the apparent kinetic parameters suggest that these residues are not required for MgATP binding, and therefore they do not appear to be part of the MgATP binding site.

Adenylate Kinase↗
PubMed1989

Morphological studies of esophageal papilloma naturally occurring in cattle.

Esophageal papillomas naturally occurring in 35 cattle were examined by light and electron microscopy. The characteristic histological lesions noted were acanthosis and parakeratosis of the mucous membrane with formation of basophilic intranuclear inclusion bodies in cells of the stratum corneum. Electron microscopically, viral particles were observed in the strata spinosum and corneum, and larger aggregations of viral particles appeared to correspond to the histological inclusions. The virus particles had a hexagonal profile, measured 35-40 nm in diameter and were arranged in crystalline arrays in some nuclei. The viral particles had morphologic characteristics indistinguishable from those of other papilloma viruses. The inclusions were stained positively by immunohistochemical methods using anti-bovine papilloma virus serum.

Animals↗
PubMed1989

Immunocytochemical component of endocrine cells in pancreatic islets of horses.

The endocrine cell components in the pancreatic islets of the following 4 pancreatic regions of the horse were investigated by immunohistochemical methods: lobus pancreatis sinister (left lobe); lobus pancreatis dexter (right lobe); and 2 regions of Corpus pancreatis (body), the duodenal lobe which lies along the cranial duodenal flexure and descending duodenum, and the intermediate lobe which is situated around the portal vein. The islets in the left and intermediate lobes contained a central mass of glucagon cells surrounded by insulin cells, a few somatostatin cells and sporadic pancreatic polypeptide (PP) cells. On the other hand, the islets in the duodenal lobe were small in size compared with the other 3 regions, and were predominant in insulin and pancreatic polypeptide (PP) cells, but almost lacked in glucagon cells. These findings suggested that the duodenal lobe was derived from the ventral pancreatic primordium, and the left and intermediate lobes were originated from the dorsal pancreatic primordium. In the right lobe, the composition and distribution of the islet cells were almost the same as those in the left and intermediate lobes, but there were several lobules containing numerous PP cells as seen in the duodenal lobe.

Animals↗
PubMed1989

Biosynthesis of benanomicins.

The biosynthesis of benanomicins A and B, produced by actinomycete strain MH193-16F4, was investigated by feeding experiments with 14C- and 13C-labeled compounds followed by measurement of radioactivity and 13C NMR analysis. A 2D double quantum coherence NMR spectrum of benanomicin A derived from sodium [1,2-13C2]acetate provided the location of intact acetate units, and confirmed the 13C assignments of benanomicins. The results indicate that the aglycone of benanomicins is derived from a dodecaketide, methionine and alanine.

Actinomycetales↗
PubMed1989

Nucleotide sequence of the macromomycin apoprotein gene and its expression in Streptomyces macromomyceticus.

A 1.6 kb Sph I-Sac I DNA fragment from Streptomyces macromomyceticus, expected to include the macromomycin (MCM) apoprotein gene, was sequenced. The fragment (1,556 bp) was found to include a putative promoter, an ORF directing pre-apoprotein which should be split into the leader peptide (Met1 to Gly32) and the MCM apoprotein (Ala33 to Ala144), and a putative terminator. The amino acid sequence deduced from the base sequence of the DNA is consistent with the amino acid sequence previously determined by the Edman degradation and other procedures applied to the protein, except base sequence AAC coding for Asn was found rather than Asp111 previously reported. The GC content of the 3rd letters throughout the ORF was 92% in contrast to the sum of the first and the second letters, 62%. There was a low GC content stretch of 20 bp (30% GC) at about 120 bp upstream of the ORF. The Pst I-Sph I 620 bp fragment including the low GC content stretch showed promoter activity when subcloned in a promoter probe vector. About 700 nucleotides long mRNA, which is long enough to span the ORF and the bordering regions, was identified using the Northern blot analysis. A primer extension experiment showed that the transcriptional starting point was A at 89 bp upstream of the ORF. Dot blot analysis of expression of MCM apoprotein gene indicated that the gene was expressed nearly constitutively, while production of holo MCM (the complex consisting of MCM apoprotein and a specific chromophore) depended greatly on culture conditions.

Amino Acid Sequence↗
PubMed1989

Mannostatins A and B: new inhibitors of alpha-D-mannosidase, produced by Streptoverticillium verticillus var. quintum ME3-AG3: taxonomy, production, isolation, physico-chemical properties and biological activities.

Mannostatins have been isolated as part of a program designed to find microorganism-produced inhibitors of alpha-D-mannosidase from Streptoverticillium verticillus var. quintum. They were purified by sequential use of active carbon and Dowex resins and then isolated as colorless powders. Mannostatins A and B have the molecular formula, C6H13NO3S and C6H13NO4S, respectively. They were competitive with the substrate, and the inhibition constants (Ki) of mannostatins A and B were 4.8 x 10(-8) M.

Cyclopentanes↗
PubMed1989

Biological activities of IC201 ((3S,8E)-1,3-dihydroxy-8-decen-5-one), a low molecular weight immunomodulator produced by Streptomyces.

IC201 was found in cultured broth of Streptomyces cirratus as an antitumor antibiotic which was effective in retarding growth of the established solid tumor of Ehrlich carcinoma by treatment starting 8 days after tumor inoculation. It retarded growth of the established solid tumor of IMC carcinoma but had no cytotoxicity at 100 micrograms/ml. IC201 treatment kept NK cell activity of tumor-bearing mice at normal level and stimulated cytostatic activity of peritoneal macrophages. It stimulated phagocytosis of yeast and phorbol myristate acetate-elicited superoxide production by peritoneal macrophages. The addition of IC201 to P388D1 cell cultures enhanced release of interleukin 1 (IL-1) into cultured supernatant but it affected lipopolysaccharide-induced IL-1 production. Although the addition to macrophage-depleted cultures did not show any stimulatory effect, mixed lymphocyte culture reaction was augmented in cultures using spleen cells as stimulator cells taken from mice given IC201. Results indicate that IC201 primarily activates macrophages and the activation may cause modulation of immune responses.

Adjuvants, Immunologic↗
PubMed1989

Orally absorbable D-forphenicinol-cephalosporins.

The synthesis and biological evaluation of D-forphenicinol-cephalosporins are described. 7-Amino-3-(substituted)-3-cephem-4-carboxylic acid esters were coupled with N-tert-butoxy-carbonyl-D-forphenicinol derivatives. Most of cephalosporin analogs in this series had good antibacterial activities and were well absorbed from the gastrointestinal tract in mice. Among them, 7-(mono-O-methyl-D-forphenicinol)-3-propenyl analog showed the most significant result in biological evaluations.

Administration, Oral↗
PubMed1989

Application of video surgery to orthodontic diagnosis.

The purpose of this project was to develop a practical methodology for predicting the visual facial changes resulting from the movement of anterior teeth. The armamentarium includes an 8-bit audiovisual computer, a video camera, a digitizer, and a cephalogram of the patient. The system outputs the patient's profile on a personal computer video display. The image is superimposed on the soft tissue line of a digitized cephalogram plot on the same display. The video profile image is transformed from analog to digital signals. The profile image digitized by the computer is modified according to average ratios of soft tissue to hard tissue changes induced by modifications to the hard tissues. The program incorporates the spline function to smooth the profile image.

Audiovisual Aids↗