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Biomedical subjects

S Manabe

Publications and source records attributed to S Manabe.

At least 109 records · Page 6Linked to original sources
PubMed1989

Pathological analyses on the compressed cord by the experimental spinal metastasis.

The purpose of the present experimental spinal metastasis developed in rats by inoculation of Walker's cancer cells through the spinous process is to find the factor which causes the initial damage of the cord in this disorder. In the early stage of paralysis, microangiogram exhibited that the degenerated posterior funiculus originated from the small hemorrhagic area in the posterior column of the involved cord. Scanning electron microscopic findings showed that the hemorrhage was of the intrinsic vein resulting from the disturbance of venous drainage in the compressed portion. In the early stage of compression, however, vascular permeability was observed in the white matter, but histologic degeneration was not. It was concluded that the trigger to induce the initial damage on the cord in spinal metastasis was likely to be the intrinsic venous hemorrhage.

Animals↗
PubMed1989

[The process of developing and improving the analytical method of benzene in organic solvents for household use: interlaboratory collaborative study].

A method for the determination of benzene in spot remover using gas chromatography (GC) and high-performance liquid chromatography (HPLC) was developed. The method was evaluated by collaborative study. There are various types of household products containing organic solvents. The collaborative study clarified that a clean-up procedure is necessary for the analysis of products other than spot remover. Thus, our improved method adopted the head space method in GC and microdiffusion method in HPLC as the clean-up procedure.

Benzene↗
PubMed1989

Anterolateral uncoforaminotomy for cervical spondylotic monoradiculopathy.

Twenty patients with cervical spondylotic monoradiculopathy treated with anterolateral uncoforaminotomy were analysed. Spondylotic spur of the level associated with radiculopathy was revealed to be continuous from the uncovertebral joint to the posterior ridge of the vertebral body in 18 patients and was observed posterolaterally in two. Anterolateral uncoforaminotomy was found to safely remove continuous type of spur, resulting in decompression of the cord-root complex, which shifted anteriorly after surgery. As a result, no neurological symptoms were observed in 19 of 20 radiculopathy patients. From our present series, it could be concluded that the most important factor in relieving neurological manifestations of this disorder is anterolateral decompression of the cord-root complex.

Adult↗
PubMed1988

Properties of cutaneous acetyltransferase catalyzing N- and O-acetylation of carcinogenic arylamines and N-hydroxyarylamine.

The role of skin for N- and O-acetylations of carcinogenic arylamine and N-hydroxyarylamine was studied in vitro. Unexpectedly high activities were observed in acetyl CoA-dependent N-acetylations of 2-aminofluorene (2-AF) and p-aminobenzoic acid (PABA) in skin cytosols of hamsters. The specific activity for 2-AF (4.52 nmoles/mg protein per min) was largely the same as that of rat liver cytosols. The cutaneous cytosols also catalyzed N,N-acetyltransfer reaction from N-hydroxy-4-acetylamino-biphenyl (N-OH-AABP) to 2-AF and acetyl CoA-dependent O-acetylation of 2-hydroxyamino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (N-OH-Glu-P-1), suggesting that hamster skin cytosol has enzymes similar to hepatic acetyltransferases. In addition, remarkably high correlations were observed between the skin and liver in the activities for N-acetylations of PABA and 2-AF. In a colony of Syrian golden hamsters a clear polymorphism was detected in the cutaneous N-acetylations of PABA and 2-AF. These animals were divided into three groups according to their activities: rapid, intermediate and slow acetylators. On the other hand, the acetylating activities in the skin and liver of these three groups showed monomorphic distribution with N-OH-AABP-dependent N,N-acetyltransfer of 2-AF and acetyl CoA-dependent O-acetylation of N-OH-Glu-P-1. These results, together with the detection of N-acetylating activity in the skin of other experimental animals and humans, suggest that skin may play an important role in the metabolism of aromatic amines and that the cutaneous acetylation in hamsters may be under the common genetic control which regulates the individual difference in the hepatic activities.

Acetylation↗
PubMed1988

Detection of carcinogenic glutamic acid pyrolysis products in Worcestershire sauce by high-performance liquid chromatography.

Commercially available Worcestershire sauce was analyzed for mutagenic and carcinogenic glutamic acid pyrolysis products using high-performance liquid chromatography. These carcinogenic heterocyclic amines were found to be present in all brands of Worcestershire sauce analyzed. The identity of the carcinogens was confirmed by spectrometric analyses and the SOS umu-test. The concentrations of 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1) and 2-amino-dipyrido[1,2-a:3',2'-d]imidazole (Glu-P-2) in the Worcestershire sauce were 695 +/- 329 pmol/liter (mean +/- SD, n = 5) and 1,839 +/- 1,321 pmol/liter (n = 5), respectively.

Amines↗
PubMed1988

Detection of N-acetyl derivative of 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1) in Glu-P-1-injected rats.

In order to confirm in vivo N-acetylation of 2-amino-6-methyl-dipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1) in rats, we developed a new high-performance liquid chromatography (HPLC) method for detecting the N-acetyl derivative of Glu-P-1 in animal organs. Using this method, N-acetyl-Glu-P-1 was detected in rat liver, kidney and intestinal contents 6 h after intraperitoneal injection of Glu-P-1. This fact provides evidence to support in vivo N-acetylation of Glu-P-1 in rats.

Acetylation↗
PubMed1988

Evaluation of a proposed standard reporting system for preoperative angiograms in infrainguinal bypass procedures: angiographic correlates of measured runoff resistance.

Preoperative angiography is widely used to estimate runoff before peripheral vascular bypass surgery. The Ad Hoc Committee on Reporting Standards for the Society for Vascular Surgery and the International Society for Cardiovascular Surgery recently proposed an angiographic scoring system that grades the quality of vessels distal to the proposed bypass site and calculates an overall runoff score after adjusting each vessel score by an arbitrary weighting factor. We compared this score with intraoperatively measured runoff resistance in 67 patients undergoing infrainguinal bypass. Correlation between overall runoff score and measured resistance varied with the distal bypass site and was reasonably predictive for femoropopliteal above-knee bypasses (r = 0.67, p = 0.004, N = 17) and femoroposterior tibial bypasses (r = 0.73, p = 0.03, N = 9), but not for femoropopliteal below-knee (r = 0.05, p = 0.76, N = 34) or femoroperoneal (r = 0.57, p = 0.18, N = 7) bypasses. When multiple linear regression was used to calculate the weighting factors (rather than using arbitrarily assigned factors), the correlation between overall angiogram score and measured resistance improved substantially for femoropopliteal above-knee (r = 0.85, p = 0.00006), femoropopliteal below-knee (r = 0.50, p = 0.03) and femoroperoneal (r = 0.83, p = 0.02) bypasses. Correlation for the entire group of 67 patients improved from r = 0.30 (p = 0.02) to r = 0.64 (p = 0.0001). We conclude that the committee's scoring system correlates with measured runoff resistance but can be improved by the use of multiple linear regression to calculate weighting factors for each vessel in the outflow tract.

Anastomosis, Surgical↗
PubMed1988

Spinal cord compression by epidural metastases. Fibrosarcoma experiments in rats.

Morphologic changes were studied in 43 rats that were paralyzed by an epidural fibrosarcoma inoculated through the spinous process. By this technique, of 29 rats examined radiographically, the tumor destroyed vertebral bone in 22. Changes of the cord in the early stage of paralysis were specially analyzed by Marchi's stain and microangiograms. In compromised cord segments in the early stage, extravasation of contrast medium was observed in the gray matter and the dorsal funiculus; and in the dorsal funiculus just proximal or distal to the compressed portion, hemorrhagic areas were present. Ascending degenerated fibers in the dorsal funiculus, which were derived from the degenerated posterior nerve root or the degeneration of the dorsal funiculus in the compressed segments, were characteristically detected in rats in the early stages. In the advanced stages a transverse cord lesion was observed at the involved level. Based on the present analyses, to prevent more advanced damage to the spinal cord, the tumor should be removed at an early stage that clinically coincides with the period when radicular signs appear.

Animals↗
PubMed1988

Metabolic activation of a protein pyrolysate promutagen 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline by rat liver microsomes and purified cytochrome P-450.

The enzymatic activation of a promutagenic pyrolysate, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), was studied using the Ames mutagenesis test system. The enzyme catalyzing the mutagenic activation of MeIQx is mainly localized in the microsomal fraction. A large number of revertants was observed in the presence of hepatic microsomes obtained from 3-methylcholanthrene (3-MC)- or polychlorinated biphenyl (PCB)-treated rats but only a minimal number with the hepatic microsomes from untreated or phenobarbital (PB)-treated rats. In addition, the microsomal activation was reduced efficiently by known inhibitors of cytochrome P-450-mediated reactions such as 7,8-benzoflavone, ellipticine and flavone. Among five forms of purified rat cytochrome P-450, the highest sp. act. (no. of revertants induced/nmol cytochrome P-450) for the activation of MeIQx was observed with a high-spin form of cytochrome P-450, P-448-H, followed by the low-spin form, P-448-L, and to a lesser extent by PB-inducible forms, P-450b and P-450e. P-450-male, which is a main constitutive form of cytochrome P-450 in male rat livers, showed considerable catalysis for the mutagenic activation of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and MeIQx. These results indicate that the metabolic activation of MeIQx is catalyzed mainly by two forms of cytochrome P-450, P-448-H and P-488-L, in the livers of PCB- or 3-MC-treated rats, but also that P-450-male may play an important role in the activation in livers of intact male rats.

Animals↗
PubMed1988

In vitro and in vivo N-acetylation of carcinogenic glutamic acid pyrolysis products in humans.

The carcinogenic glutamic acid pyrolysis products, 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1) and 2-aminodipyrido[1,2-a:3',2'-d]imidazole (Glu-P-2), and their N-acetyl derivatives have been demonstrated to be present in human urine, bile, liver and kidney. In vitro experiments have revealed that Glu-P-1 and Glu-P-2 are N-acetylated to form N-acetyl derivatives by the cytosolic fraction from a human autopsy liver specimen. From these results our data strongly suggest that Glu-P-1 and Glu-P-2 derived from everyday foods are partially N-acetylated in human organs and that they are excreted in bile and urine with their N-acetyl derivatives. Our data also provide the first reliable evidence that humans can metabolize the carcinogenic heterocyclic amines.

Acetylation↗
PubMed1988

Presence of carcinogenic glutamic-acid pyrolysis products in human cataractous lens.

The carcinogenic glutamic-acid pyrolysis products, 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1) and 2-amino-dipyrido[1,2-a:3',2'-d]imidazole (Glu-P-2), were found to be present in human cataractous lenses, but not in normal bovine lenses. Contents of Glu-P-1 and Glu-P-2 in 35 human cataractous lenses were 832 and 20 ng, respectively. These results indicate that the human cataractous lens is exposed to the fluorescent compounds, carcinogenic glutamic pyrolysis products.

Aged↗
PubMed1988

Carcinogenic tryptophan pyrolysis products potent inhibitors of type A monoamine oxidase and the platelet response to 5-hydroxytryptamine.

The effects of carcinogenic heterocyclic amines and beta-carbolines on 5-hydroxytryptamine-induced human platelet aggregation, on the uptake of 5-hydroxytryptamine by platelets, and on human monoamine oxidase activity were investigated. Of the dietary carcinogens and beta-carbolines studied, carcinogenic tryptophan pyrolysis products had greater pharmacological activities than other heterocyclic amines. The carcinogenic tryptophan pyrolysis products, 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole and 3-amino-1-methyl-5H-pyrido[4,3-b]indole, which have been identified in the dialysis fluid of uraemic patients, were the most potent inhibitors of the aggregation response to 5-hydroxytryptamine, with IC50 (the concentrations causing 50% inhibition) values of 10 mumol/l and 50 mumol/l, respectively. 3-Amino-1,4-dimethyl-5H-pyrido[4,3-b]indole and 3-amino-1-methyl-5H-pyrido[4,3-b]indole by themselves did not induce platelet aggregation, although these dietary carcinogens structurally resemble 5-hydroxytryptamine. Kinetic analyses showed that 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole and 3-amino-1-methyl-5H-pyrido[4,3-b]indole were potent competitive inhibitors of 5-hydroxytryptamine uptake by platelets with Ki 18 mumol/l and 42 mumol/l, respectively. Furthermore, carcinogenic tryptophan pyrolysates as well as beta-carbolines were found to be competitive selective inhibitors of monoamine oxidase 'type A'.

Blood Platelets↗
PubMed1988

Incidence and ultrastructure of rudimentary cilia in benign and malignant peripheral nerve tumors.

The incidence and ultrastructure of cilia were examined in 26 peripheral nerve tumors. The cilia had the common features of elongated shafts and basal structures consisting of two basal bodies. The basal body contained two basal feet and some long striated rootlets. The cilia lacked central tubules and two dynein arms of subfiber A, suggesting that they were nonmotile and rudimentary. The quantitative results showed that the incidence of cilia was low in Schwann cells and fibroblasts of the 20 benign tumors and slightly higher in perineurial cells of the 12 neurofibromas. Conversely, the incidence was high in most of the 6 malignant tumors. Only one perineurial cell from normal mature nerve examined carried a cilium, although no cilia were seen in the other perineurial cells, Schwann cells, and fibroblasts observed. The results showed that ciliary formation was more marked in the more actively proliferating tissues such as malignant tumors, and less so in the less actively proliferating tissues such as benign tumors. Ciliary formation may be one of the ultrastructural features commonly observed in proliferative tissues.

Cilia↗
PubMed1988

Alkaline bismuth solution as an en bloc stain for formaldehyde-glutaraldehyde potassium permanganate fixed fungal spores.

An alkaline solution of bismuth subnitrate reacted well with the cell membranes and cell walls of formaldehyde-glutaraldehyde potassium permanganate fixed Alternaria spores, demonstrating them with greater contrast than in sections stained with uranyl acetate and lead citrate. Optimal fine structure of fungal spores was obtained by en bloc staining with alkaline bismuth solution after aldehyde and permanganate fixation. The contrast of the cell organelles and cell walls was high enough in sections cut after the alkaline bismuth en bloc stain for direct ultrastructural observation. Our results indicate that the alkaline bismuth stain is useful either as an en bloc or section stain for aldehyde and permanganate fixed fungal spores.

Alternaria↗
PubMed1988

Anterolateral uncoforaminotomy for cervical spondylotic myeloradiculopathy.

Thirty-five patients with cervical spondylotic radiculopathy and myeloradiculopathy had anterolateral uncoforaminotomy. Spondylotic spurs associated with radiculopathy were continuous from the uncovertebral joint to the posterior ridge of the vertebral body in 33 patients and to the posteriorly bulging disc with posterolateral bony spurs in 2 patients. Anterolateral uncoforaminotomy was found safe to remove the continuous type of spur, resulting in decompression of the cord-root complex, which shifted anteriorly after surgery. The outcome was satisfactory in 19 of 20 radiculopathy patients, and in all 15 myeloradiculopathy patients. Decompression of the cord-root complex is the most important factor in relieving neurologic manifestations of cervical spondylosis.

Adult↗