Search PubMed⌕ Search

Biomedical subjects

E Nakamura

Publications and source records attributed to E Nakamura.

At least 109 records · Page 6Linked to original sources
PubMed1994

The true nature of the adductor brevis dually innervated by the anterior and posterior branches of the obturator nerve in humans.

To clarify the true nature and the mechanism of the human adductor brevis (specific adductor brevis, SAB) innervated dually by the anterior and posterior branches of the obturator nerve, we have carried out gross anatomical examination of 100 body halves of 50 adult Japanese cadavers. The SAB was found in 23 of the 100 thighs (23.0%), and its anterior and posterior surfaces received respectively the twigs from the anterior branch of the obturator nerve and the filament(s) from the posterior branch. The filament(s) was either indirectly derived from the medial stratum of the posterior branch through the formation of a common trunk with the twigs distributed in the obturator externus (14/23 thighs, 60.9%) or directly originating in the medial stratum of the posterior branch of the obturator nerve (9/23 thighs, 39.1%). In the close examination of the intramuscular distribution of the nerve to the SAB, the region innervated by the anterior branch of the obturator nerve could clearly be distinguished from that innervated by the posterior branch. The obturator nerve received fibers from L1234 (2/23 thighs) or from L234 (21/23 thighs), and the posterior branch of the obturator nerve ran through the obturator externus (18/23 thighs, 78.3%) or ran over the obturator externus (5/23 thighs, 21.7%), and finally emerged into the thigh. In view of the mode of origin of the filament(s), the structural element of the filament(s), and the pattern of entry of the filament(s) into the SAB, the fasciculus of the SAB, which is innervated by the posterior branch of the obturator nerve, was considered to originate in the obturator externus. Thus, the true nature of the SAB was concluded to be a complex product which was formed by a mechanism in which the fasciculus, which had separated from the obturator externus during the process of ontogeny, fused secondarily to the posterior surface of the regular adductor brevis. From findings in our series of studies, it was estimated that the maximum frequency of occurrence of the SAB could be 56%. Furthermore, from a statistical point of view, the segmental composition or course of the obturator nerve is not considered to be related to either the formation or the incidence of this muscle.

Humans↗
PubMed1994

Disposition and metabolism of a novel diurea inhibitor of acyl CoA: cholesterol acyltransferase (YM17E) in the rat and dog.

1. We have investigated the disposition and metabolism of YM17E after intravenous and oral administration in the rat and dog. 2. Bioavailability of YM17E was 5-9% at oral doses of 3-30 mg/kg in rat, and 9 and 13% at oral doses of 10 and 30 mg/kg in dog. 3. Five N-demethylated metabolites, which have significant pharmacological activity, were found in rat and dog plasma after oral administration. Plasma concentrations of each of these metabolites were comparable with that of unchanged drug. 4. When 14C-YM17E was administered to rat, AUC of unchanged drug was 7% of that of radioactivity. However, AUC of the combined concentration of unchanged drug and five active metabolites was about 50% of that of radioactivity, indicating that the pharmacological activity of the agent was maintained in spite of its biotransformation. 5. After oral administration of 14C-YM17E at a dose of 10 mg/kg to rat, radioactivity was distributed widely to almost all tissues except the brain. The concentration of radioactivity in the liver, one of the target organs, was 65 times higher than that in plasma at 1 h after administration. 6. A significant amount of radioactivity in the liver was located in the microsomal subfraction, which contains much acyl CoA:cholesterol acyl transferase activity. More than 50% of this microsomal radioactivity was derived from unchanged YM17E and five active metabolites. 7. From excretion data in the bile duct-cannulated rat, the absorption ratio of YM17E from the gastrointestinal tract in this species was estimated to be at least 40%, suggesting that the low bioavailability of the drug is due to extensive first-pass metabolism. 8. Some 95% of the administered radioactivity was excreted in the faeces of rat following iv or po doses of 14C-YM17E.

Animals↗
PubMed1994

Stress-protecting effects of semi-rigid titanium alloy plates on osteotomized rabbit tibiae.

We have examined the stress-protecting effects of titanium alloy (Ti-6A1-4V) plates of various thicknesses on osteotomized rabbit tibiae. We used three kinds of plates: One had a load-deflection rate close to that of intact rabbit tibiae (Group A), the other two had rates of one-fourth (Group B) and one-eighth (Group C) that of intact rabbit tibiae. No mechanical failure in the plates was observed, and bone healing occurred by eight weeks after operation in every group. Bone mass at 24 weeks after operation showed significantly less reduction in Groups B and C than in Group A. In biomechanical tests at 24 weeks, maximum energy stored to the maximum load in Group C had recovered significantly more than that of Group A. These findings suggested that it is possible to make a semi-rigid metal plate without using composite materials.

Alloys↗
PubMed1993

Purification, characterization and molecular cloning of an acidic amino acid-specific proteinase from Streptomyces fradiae ATCC 14544.

We have isolated a novel acidic amino-acid-specific proteinase from Streptomyces fradiae ATCC 14544, using benzyloxycarbonyl-L-Phe-L-Leu-L-Glu-p-nitroanilide (Z-Phe-Leu-Glu-pNA) as a substrate. A proteinase, which we propose to call SFase, was purified from the culture filtrate by salting out, repeated S-Sepharose chromatography, and affinity chromatography (CH-Sepharose-Phe-Leu-D-Glu-OMe). The purified enzyme showed a single band having an apparent molecular weight of 19,000 on sodium dodecyl sulfate polyacrylamide gel electrophoresis. When synthetic peptides were used as substrates, SFase showed high specificity for Z-Phe-Leu-Glu-pNA. Comparison with nitroanilides of glutamic acid and aspartic acid as substrates revealed that the reactivity was about 10-fold higher for a glutamyl bond than an aspartyl bond. SFase selectively hydrolyzed the -Glu-Ala-bond of two glutamyl bonds in the oxidized insulin B-chain within the initial reaction time until the starting material was completely digested. Diisopropylfluorophosphate and benzyloxycarbonyl-Phe-Leu-Glu chloromethylketone completely inhibited SFase, while metalloproteinase inhibitors, such as EDTA and o-phenanthrolin, did not inhibit the enzyme. The findings indicate that SFase can be classified as a serine proteinase, and is highly specific for a glutamyl bond in comparison with an aspartyl bond. To elucidate the complete primary structure and precursor of SFase, its gene was cloned from genomic DNA of the producing strain, and the nucleotide sequence was determined. Consideration of the N- and C-terminal amino-acid sequences of the mature protein of SFase indicates that it consists of 187 amino acids, which follows a prepropeptide of 170 residues. In comparison with the acidic amino-acid-specific proteinase from Streptomyces griseus (Svendsen, I., Jensen, M.R. and Breddam, K. (1991) FEBS Lett. 292, 165-167), SFase had 82% homology in the amino acid sequence. The processing site for maturation of SFase was a unique sequence (-Glu-Val-), so that the propeptide could be released by cleavage of the peptide bond between Glu and Val.

Amino Acid Sequence↗
PubMed1993

The advantage of primary resection and anastomosis with intraoperative bowel irrigation for obstructing left-sided colorectal carcinoma.

Of a total 712 patients with left-sided colorectal cancer, 79 (11%) required emergency surgery due to severe obstruction by tumors. Of these 79 patients, 55 underwent tumor resection and anastomosis. Primary resection and anastomosis with intraoperative bowel irrigation was performed in 44 patients (primary group), while staged resection and anastomosis was performed in only 11 (staged group). In comparing the two groups, there was no significant difference in the rates of curative resection, being 76% versus 90%. However, the primary group demonstrated significantly lower rates of postoperative wound infection (P < 0.001), anastomotic dehiscence (P not equal to 0.05), and postoperative mortality, at 2% versus 18% (P < 0.05). The cumulative survival curve was also better in the primary group (P < 0.05). These favorable results of the primary group were confirmed by analyses which established that no bias of therapeutic backgrounds existed in either of the two groups. Thus, it was concluded that for left-sided obstructing colorectal carcinoma, intraoperative bowel irrigation, followed by primary resection and anastomosis, produces more advantageous results.

Adult↗
PubMed1993

Steroid-related bilateral osteonecrosis of the patella.

We present a case of bilateral osteonecrosis of the patella in a patient during steroid therapy and demonstrate the radiological, arthroscopic, and histological features. Osteonecrosis of the patella should be considered as a possible cause of knee pain in patients receiving steroid therapy.

Arthroscopy↗
PubMed1993

Knee articular cartilage injury in leg lengthening. Histological studies in rabbits.

The effect of lengthening the tibia, by callotasis on the articular cartilage in the knee, was investigated histologically in 18 rabbits. The distraction rate was 1 mm per day. On the right tibia, the distraction frequency was in 2 steps (0.5mm/12 hours), while on the left it was in 120 steps (0.0083 mm/12 minutes). The 18 animals were divided into 3 subgroups based on length gain. Cartilage and subchondral bone samples were examined by light and fluorescent microscopy. The incidence of cartilage degeneration on the 2-step side was 2/5, 5/6, and 6/7 at 10, 20, and 30 percent length increases. On the 120-step side it was 0/5, 1/6, and 1/7 at the same length increases. The intensity of tetracycline fluorescence of the subchondral plate on the 2-step side was higher than that on the 120-step side, showing 1.7, 2.0, and 2.3-fold increases at 10, 20, and 30 percent length increases. Our study suggests that increasing the frequency of distraction in callotasis can help to prevent damage to articular cartilage in adjacent joints.

Animals↗
PubMed1992

Purification, characterization, cloning, and expression of a glutamic acid-specific protease from Bacillus licheniformis ATCC 14580.

A glutamic acid-specific protease has been purified to homogeneity from Bacillus licheniformis ATCC 14580 utilizing Phe-Leu-D-Glu-OMe-Sepharose affinity chromatography and crystallized. The molecular weight of the protease was estimated to be approximately 25,000 by SDS-polyacrylamide gel electrophoresis. This protease, which we propose to call BLase (glutamic acid-specific protease from B. licheniformis ATCC 14580), was characterized enzymatically. Using human parathyroid hormone (13-34) and p-nitroanilides of peptidyl glutamic acid and aspartic acid, we found a marked difference between BLase and V8 protease, EC 3.4.21.9, although both proteases showed higher reactivity for glutamyl bonds than for aspartyl bonds. Diisopropyl fluorophosphate and benzyloxycarbonyl Leu-Glu chloromethyl ketone completely inhibited BLase, whereas EDTA reversibly inactivated the enzyme. The findings clearly indicate that BLase can be classified as a serine protease. To elucidate the complete primary structure and precursor of BLase, its gene was cloned from the genomic DNA of B. licheniformis ATCC 14580, and the nucleotide sequence was determined. Taking the amino-terminal amino acid sequence of the purified BLase into consideration, the clones encode a mature peptide of 222 amino acids, which follows a prepropeptide of 94 residues. The recombinant BLase was expressed in Bacillus subtilis and purified to homogeneity. Its key physical and chemical characteristics were the same as those of the wild-type enzyme. BLase was confirmed to be a protease specific for glutamic acid, and the primary structure deduced from the cDNA sequence was found to be identical with that of a glutamic acid-specific endopeptidase isolated from Alcalase (Svendsen, I., and Breddam, K. (1992) Eur. J. Biochem. 204, 165-171), being different from V8 protease and the Glu-specific protease of Streptomyces griseus which consist of 268 and 188 amino acids, respectively.

Amino Acid Sequence↗
PubMed1992

Characterization of recombinant human and rat pancreatic phospholipases A2 secreted from Saccharomyces cerevisiae: difference in proteolytic processing.

An expression plasmid for human pancreatic phospholipase A2 in Saccharomyces cerevisiae was constructed by insertion of cDNA encoding its preprophospholipase A2 into a yeast expression vector pAM82. The resulting product secreted in the yeast culture medium was mainly prophospholipase A2, which was the same as the natural proenzyme in all aspects examined, including the higher order structure. However, when the rat preprophospholipase A2 cDNA was manipulated in the same manner, the active phospholipase A2 of the intact mature form was secreted with the proenzyme being hardly detected in the medium. This unexpected favorable result would occur due to cleavage of rat phospholipase A2 pro-peptide by a trypsin-like proteinase in S. cerevisiae. Based on this finding, we constructed a plasmid carrying the sequence coding for the prepro-peptide of rat pancreatic phospholipase A2 behind the PHO5 promoter in the pAM82 vector, which leads to the secretion of heterologous proteins as their mature form. The use of this plasmid led to secretion of biologically active human pancreatic secretory trypsin inhibitor and a glutamic acid-specific endopeptidase from Staphylococcus aureus ATCC 12600, which are eukaryote and prokaryote proteins, respectively, in the culture medium of S. cerevisiae.

Amino Acid Sequence↗
PubMed1992

Purification, characterization and gene cloning of a novel glutamic acid-specific endopeptidase from Staphylococcus aureus ATCC 12600.

Twenty strains of Staphylococcus aureus from ATCC type cultures and strains found in clinical studies were cultivated, and their endopeptidase activity specific for glutamic acid was surveyed using benzyloxycarbonyl-Phe-Leu-Glu-p-nitroanilide (Z-Phe-Leu-Glu-pNA) as a substrate. The activity was found in two of the strains, ATCC 12600 and ATCC 25923. A glutamic acid-specific proteinase, which we propose to call SPase, was purified from the culture filtrate of S. aureus strain ATCC 12600 by a series of column chromatographies on DEAE-Sepharose twice and on Sephacryl S-200. A single band was observed on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of the purified SPase. The molecular weight of the proteinase was estimated to be 34000 by SDS-PAGE. When synthetic peptides and oxidized insulin B-chain were used as substrates, SPase showed the same substrate specificity as V8 proteinase, EC 3.4.21.9, which specifically cleaves peptide bonds on the C-terminal side of glutamic acid and aspartic acid. Examination with p-nitroanilides of glutamic acid and aspartic acid as substrates, however, revealed that both proteinases are highly specific for a glutamyl bond in comparison with an aspartyl bond. To elucidate the complete primary structure of SPase, its gene was cloned from genomic DNA of S. aureus ATCC 12600, and the nucleotide sequence was determined. Taking the amino acid sequence of SPase from the NH2-terminus to the 27th residue into consideration, the clones encode a mature peptide of 289 amino acids, which follows a prepropeptide of 68 residues. SPase was confirmed to be a novel endopeptidase specific for glutamic acid, being different from V8 proteinase which consists of 268 amino acids.

Amino Acid Sequence↗
PubMed1992

Secretory expression of a glutamic-acid-specific endopeptidase (SPase) from Staphylococcus aureus ATCC12600 in Bacillus subtilis.

In order to obtain a large quantity of glutamic-acid-specific endopeptidase of Staphylococcus aureus ATCC12600 (SPase) without cultivating its pathogenic host bacterium, expression plasmids enabling secretion of SPase from Bacillus subtilis were constructed by inserting the SPase gene into B. subtilis-Escherichia coli shuttle vectors. B. subtilis harbouring a simple recombinant plasmid containing the coding and the 5'-flanking regions of SPase in the shuttle vector pHY300PLK secreted 22 mg/l of SPase into the medium. As this level was lower than that of the natural strain (45 mg/l), we tried to increase the expression level by constructing a series of hybrid plasmids with the following features: (1) the terminator sequence of the alkaline protease gene from B. subtilis, (2) the promoter and the leader sequences of the alpha-amylase gene or of alkaline protease gene from B. amyloliquefaciens, (3) the vector pHY300PLK and the fused vector of pHY300PLK and pUB110. By using a variety of hybrid plasmids, the resulting transformants secreted SPase at levels of 33-120 mg/l. The recombinant SPase isolated from the medium was indistinguishable from the natural one with respect to its behaviour on sodium dodecyl sulphate-polyacrylamide gel electrophoresis and Western blotting as well as its enzyme activity.

Amino Acid Sequence↗
PubMed1992

A method for the calculation of protein alpha-CH chemical shifts.

The chemical shifts of C(alpha)H protons have been calculated for 9 proteins, based on coordinates taken from high-resolution crystal structures. Chemical shifts were calculated using ring-current shifts, shifts arising from magnetic anisotropies of bonds, and shifts arising from the polarizing effect of polar atoms on the C(alpha)H bond. The parameters used were refined iteratively to give the best fit to (experimental-random coil) shifts over the set of 9 proteins. A further small correction was made to the averaged Gly C(alpha)H shift. The calculated shifts match observed shifts with correlation coefficients varying between 0.45 and 0.86, with a standard deviation of about 0.3 ppm. The differences between calculated and observed shifts have been studied in detail, including an analysis of different crystal structures of the same protein, and indicate that most of the differences can be accounted for by small differences between the structure in solution and in the crystal. Calculations using NMR-derived structures give a poor fit. The calculations reproduce the experimentally observed differences between chemical shifts for C(alpha)H in alpha-helix and beta-sheet. Most of the differentiation in secondary-structure-dependent shifts arises from electric field effects, although magnetic anisotropy also makes a large contribution to the net shift. Applications of the calculations to assignment (including stereospecific assignment) and structure determination are discussed.

Carbon↗
PubMed1992

A supernumerary muscle between the adductors brevis and minimus in humans.

In order to elucidate the nerve supply of a supernumerary muscle observed between the adductors brevis and minimus in humans and to investigate its true nature and mechanism of formation, 100 body halves from 50 adult Japanese cadavers were subjected to gross anatomical examination. A supernumerary muscle was noted in 33 (33.0%) out of the 100 thighs. In each of these thighs, it arose from the upper part of the inferior ramus of the pubis and ran obliquely downwards and laterally. It was inserted into the anterior surface of the insertion aponeurosis of the adductor minimus (17/33 thighs, 51.5%), the upper part of the pectineal line (9/33 thighs, 27.3%), or the posterior side of the base of the lesser trochanter (7/33 thighs, 21.2%). It was supplied, from its posterior aspect, by a filament from the twig originating from the posterior branch of the obturator nerve and being distributed to the superficial fasciculus of the obturator externus (18/33 thighs, 54.5%) or by a twig directly originating from the posterior branch (15/33 thighs, 45.5%). The obturator nerve received fibers from L1234 (4/33 thighs), L234 (25/33 thighs), L2345 (2/33 thighs) or L34 (2/33 thighs) and, moreover, its posterior branch ran through (25/33 thighs, 75.8%) or over (8/33 thighs, 24.3%) the obturator externus to emerge into the thigh. Based on the topographical-anatomical relationships of this muscle to its nerve supply, it seems probable that it is formed by separation from the superficial layer of the obturator externus and changes into an independent structure during the process of ontogeny. Furthermore, from a statistical standpoint, the segmental composition or course of the obturator nerve is not related to either the formation or incidence of this muscle.

Cadaver↗
PubMed1992

Synthesis and biological activities of cyclopropenone antibiotic penitricin and congeners.

A number of derivatives of the cyclopropenone antibiotic penitricin have been synthesized by the reaction of metalated cyclopropenone acetals with electrophiles. Studies on the antimicrobial structure-activity relationships indicated that the penitricin skeleton, hydroxymethylcyclopropenone, is indispensable for antimicrobial activity. These compounds were also found to display cytotoxic activity.

Bacteria↗
PubMed1992

[Comparative study of risk criteria for germ cell tumor].

The development of cisplatin-based chemotherapy has achieved a high cure rate in patients with advanced germ cell tumors (GCT) and it is more important to predict the prognosis of each patient before treatment and select the most suitable regimen of therapy. To date, 4 risk criteria for GCT are presented. From November, 1985 to April, 1991 our treatment protocol for GCT consisted of VAB-6 (vinblastine, actinomycin D, bleomycin, cisplatinum) or PVeBV (vinblastine, etoposide, bleomycin, high-dose cisplatin) as the induction chemotherapy and VIP (etoposide, ifosfamide, cisplatin) as the salvage chemotherapy. In total, 12 patients were entered on this protocol. They were divided into 2 groups based on the actual clinical course. Those who achieved complete remission within 3 cycles of chemotherapy were divided into "good response group" and others were into "poor response group". These results were compared with those classified by the 4 risk criteria. As a result of our study "The Indiana Staging System" seemed to be the most useful.

Adult↗
PubMed1991

Structure of (+/-)-(2S,1'S)-2-[hydroxy(phenyl)methyl]-2-methylcyclohexanone, C14H1802.

Mr = 281.30, monoclinic, P2(1)/n, a = 10.966 (4), b = 7.170 (3), c = 15.976 (4) A, beta = 93.14 (2) degrees, V = 1254.3 (9) A3, Z = 4, Dx = 1.16 g cm-3, lambda (Mo K alpha) = 0.71069 A, mu = 0.706 cm-1, F(000) = 472, T = 295 K, final R = 0.057 for 1212 unique observed reflections. The compound was prepared by reaction of the trichlorotitanium-delta 1(2)-enolate of 2-methylcyclohexanone with benzaldehyde.

Cyclohexanones↗
PubMed1991

A study on the basic nature of human biological aging processes based upon a hierarchical factor solution of the age-related physiological variables.

The purpose of this study is to determine the laws governing the aging processes based on a hierarchical factor solution of the age-related physiological variables. Healthy individuals (462) who had taken a 2-day health examination were studied. Twenty-seven physiological variables were submitted to hierarchical factor solution. The analysis revealed that there was a fixed pattern in the variations of these 27 physiological variables. In this hierarchical factor solution, three group factors as functioning at different levels of complexity composed of the 16 common factors were extracted. Of these group factors, the first and third group factors can be referred to the aging process. The first group factor, the so-called factor 1 loaded with most of physiological variables, was interpreted as a primary aging factor which presented the primary process of human aging. The third group factor, the so-called factor 6 to 16 loaded only with a few variables related to a single physiological system or organ, were interpreted as system-specific secondary aging factor. These results obtained by the hierarchical factor solution thus seem to support the notion that biological age changes can be viewed as time dependent complex integration of the primary and secondary aging processes.

Adult↗