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Biomedical subjects

M Chen

Publications and source records attributed to M Chen.

At least 901 records · Page 50Linked to original sources
PubMed1985

[An autopsy case of extraneural metastases of giant cell glioblastoma with intracerebral hemorrhage].

We report a case in which a 71-year-old man with a giant cell glioblastoma who had a spontaneous intracerebral hematoma including subarachnoid hemorrhage and extraneural multiple metastases followed by the craniotomy 9 months later. He had complained of nausea and vomiting on 20, October, 1981 and admitted to the Ohara hospital. For that reason, he was admitted to our hospital on 29, October, 1981 and a CT scan showed a large subcortical high dence mass accompanied by adjacent edema in the right frontal lobe. Gradually he got worse with Korsakoff's syndrome and motor weakness of the left side. Total removal of the hematoma and adjacent tissue by transcortical route on 24, November, 1981 was performed, followed by 60Co radiation therapy to the local area, chemotherapy and immunotherapy. The surgical specimen showed typical features of giant cell glioblastoma with intratumoral hemorrhage. After 9 months of the operation, he had complained of the subcutaneous tumor in the supraclavicular region and swelling of the right arm. After the second admission on 30, August, 1982, a biopsy of the tumor revealed malignant tumor cells resembling intracerebral giant cell glioblastoma. He died on 29, November, 1982. At autopsy, extraneural metastases were revealed at some lymph nodes, organs and bones. However, a primary tumor was not found in the other organs. Lymph node: cervical, supraclavicular, mediastinal, bronchial, pancreaticoduodenal, hepatic hilus, mesenteric, retroperitoneal, and parastomach. Organ: esophagus, Ileum, jejunum, adrenal gland and kidney. Bone: vertebra (thoraco-lumbar), sternum, rib. Positive reaction to GFA protein antibody was demonstrated in the tumor cells in the periphery of the surgical specimen of the brain tumor.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1984

The physico-chemical properties of cancer-suppressive factor.

Biological fluids of mammalia possess a cancer-suppressive activity. CSF has been isolated from ascitic fluid (Ehrlich ascites carcinoma) in this laboratory. Chemically, it is a peptide complexing with lipids, and inhibits the cancer cells in vitro, but has a little effect on normal bone marrow cells. This paper reports the molecular homogeneity, amino acid composition, approximate molecular weight and terminal structures of the peptide.

Amino Acid Sequence↗
PubMed1984

A study on serum cancer-suppressive peptide.

A peptide which was isolated from serum of cancer-bearing mice has an activity to kill cancer cells in vitro, but little effect on bone marrow cells. This peptide was named Serum Cancer-Suppressive Peptide (SCSP). SCSP can be crystallized and still has the activity to kill the cancer cells. It consists of more than ten kinds of amino acids with molecular weight about 2000-3000 daltons estimated by SDS-polyacrylamide gel electrophoresis. An antiserum was prepared from rabbits immunized with SCSP and the corresponding IgG could be obtained from the antiserum. The titers of SCSP in some cells of the normal and cancer-bearing mice were estimated by passive hemagglutination method. The results showed that the SCSP titer in spleen is much higher than those in muscle, liver and ascites tumor cells. The results suggest that SCSP is probably produced by spleen cells.

Amino Acids↗
PubMed1983

Morphological basis of long-term habituation and sensitization in Aplysia.

The morphological basis of the persistent synaptic plasticity that underlies long-term habituation and sensitization of the gill withdrawal reflex in Aplysia californica was explored by examining the fine structure of sensory neuron presynaptic terminals (the critical site of plasticity for the short-term forms of both types of learning) in control animals and in animals whose behavior had been modified by training. The number, size, and vesicle complement of sensory neuron active zones were larger in animals showing long-term sensitization than in control animals and smaller in animals showing long-term habituation. These changes are likely to represent an anatomical substrate for the memory consolidation of these tasks.

Animals↗
PubMed1983

Effect of 6-hydroxydopamine on in vitro hippocampal corticosterone binding capacity in the male rat.

Adult male rats were injected with 6-hydroxydopamine, either into the lateral brain ventricle or directly into the dorsal hippocampus. They were adrenalectomized 5-7 days later, and following an additional 24 hours, the specific in vitro 3H-corticosterone binding capacity of dorsal hippocampal slices was determined by estimation of uptake of radioactivity by the nuclear fraction. Specific corticosterone binding was reduced by 40-50% in both experimental groups, as compared to vehicle-treated controls. These results suggest that the maintenance of normal dorsal hippocampal corticosterone binding capacity is dependent upon the integrity of endogenous brain catecholaminergic neural systems.

Animals↗
PubMed1983

In vitro and in vivo technique for assessing vagus nerve regeneration after parietal cell vagotomy in the rat.

This study determined if the vagus nerve can regenerate and/or reinnervate the gastric parietal cell mass after parietal cell vagotomy (PCV) and examines tests for assessing vagus nerve regeneration in rats. Microscopic dissection of the neurovascular bundle allowed the vagus nerve to be divided at the gastric body with preservation of the antropyloric nerve and gastric vasculature. Gastric secretory tests were performed under basal and stimulated conditions using secretagogues and insulin hypoglycemia. The candidate hormone, pancreatic polypeptide, was measured in plasma following a mixed meal, insulin hypoglycemia and i.v. secretin. Rats were killed weekly for 9 weeks and the vagal nerve distribution examined by both light and electron microscopy. Stimulated gastric acid output fell from 164 to 26 mumol/h immediately after operation (P less than 0.001). One week following PCV, the nerves were swollen with fibroblast infiltration and collagen around axon groups showed degeneration. By the third week after PCV, the axons were more densely packed with neurofilaments and acid output had increased to 183 mumol/h. In the fourth and fifth weeks, the enlarged Schwann cell processes had more axons and acid output rose to 262 mumol/h. By the seventh week, both large and small axons were identified and the acid output was 93% higher than the preoperative level (P less than 0.001). PCV and antrectomy also was followed by reinnervation of the gastric mucosa. Pancreatic polypeptide concentration in plasma was virtually unchanged following ingestion of food, insulin hypoglycemia or secretin. In rats, following PCV, gastric secretory tests and electron microscopy seem to be the most reliable methods of assessing vagus nerve regeneration.

Animals↗
PubMed1983

Hippocampal cell nuclear binding of corticosterone following 5,7-dihydroxytryptamine.

Adult male rats were injected into the lateral brain ventricle with 5,7-dihydroxytryptamine (5,7-DHT). They were adrenalectomized 5-7 days later and, following an additional 24 h, the specific in vitro [3H]corticosterone binding capacity of dorsal hippocampal slices was determined by estimation of uptake of radioactivity by the nuclear fraction. Specific corticosterone (CS) binding was reduced by 50-70% in the neurotoxin-treated as compared to vehicle-injected animals. Brain serotonin and 5-hydroxyindoleacetic acid concentrations were depleted by 50-70% in the 5,7-DHT-injected rats. These results suggest that the maintenance of normal dorsal hippocampal CS binding capacity is dependent upon the integrity of endogenous brain serotoninergic neuronal systems.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1983

Behavioral changes in aging Aplysia: a model system for studying the cellular basis of age-impaired learning, memory, and arousal.

The marine mollusc Aplysia californica was used to examine the effects of age on simple forms of learning, memory, and arousal. We have found that aging impairs the long-term retention of habituation and prevents the acquisition of sensitization in the siphon withdrawal reflex. In addition, aging reduces arousal as evident in the heart rate component of the response to food stimuli. Our results are similar to the age-dependent alterations in the capacity for behavioral plasticity that have been reported in a variety of vertebrates, including man. These similarities suggest that the mechanisms underlying the effects of age on behavior and its modification may share common features across phyla and therefore might be studied to advantage in Aplysia whose central nervous system is especially accessible to cell biological approaches.

Aging↗
PubMed1983

Adaptation of mesophilic anaerobic sewage fermentor populations to thermophilic temperatures.

Thermophilic (50 degrees C) and obligately thermophilic (60 degrees C) anaerobic carbohydrate- and protein-digesting and methanogenic bacterial populations were enumerated in a mesophilic (35 degrees C) fermentor anaerobically digesting municipal primary sludge. Of the total bacterial population in the mesophilic fementor, 9% were thermophiles (36 x 10(6)/ml) and 1% were obligate thermophiles (4.5 x 10(6)/ml). Of these 10%, the percentages of bacteria (thermophiles and obligate thermophiles, respectively) able to use specific substrates were further enumerated as follows: bacteria able to digest albumin, casein, starch, and mono- and disaccharides, 30 and 10%; pectin degraders, 10 and 0.2%; cellulose degraders, 2 and 0.06%; methanogens that grow with H2 and CO2, methanol, and dimethylamine, 9 and 1%; methanogens that grow with formate, 8 and 5%; and methanogens that grow with acetate, 25 and less than 0.8%. Shortly after the temperature was elevated from 35 to 50 or 60 degrees C, the digestion of albumin, casein, starch, and mono- and disaccharides was detected, and methane was produced from H2 and CO2. Methane produced from acetate was not delayed at 50 degrees C, but was delayed by 29 days at 60 degrees C. Methane produced from formate was delayed by 3 days, from methanol by 7 days, and from dimethylamine by 5 days at 50 and 60 degrees C. A 10- and 20-day acclimation period was required for hydrolysis of pectin and cellulose, respectively, at 50 degrees C. Digestion of pectin required 20 days and cellulose longer than 85 days when the temperature was elevated abruptly from 35 to 60 degrees C. The acclimation period for the digestion of pectin and cellulose at 60 degrees C was shortened to 3 and 15 days, respectively, by seeding with a small amount of a culture acclimated to 50 degrees C. The data suggest that enrichment of cellulolytic, pectinolytic, and acetate-utilizing bacteria is crucial for the digestion of sewage sludge at 60 degrees C.

Acetates↗
PubMed1983

Modification of delayed-incubation procedure for detection of fecal coliforms in water.

Three holding media, including the vitamin-free Casitone holding medium (m-VFC) recommended by Standard Methods for the Examination of Water and Wastewater for use with the delayed-incubation membrane filter procedure, were compared for their ability to maintain viability of fecal coliforms. Each medium was tested according to the procedure described in the above reference with 60 to 80 pure cultures of fecal coliforms and a variety of natural water samples containing fecal coliforms. Fecal coliform recovery with m-ST holding medium (containing ethanol, sulfanilamide, and Tris [pH 8.6] was significantly greater than recovery with m-VFC (containing vitamin-free casein hydrolysate, sodium benzoate, sulfanilamide, and ethanol). Recovery with m-VFC, was, in turn, significantly greater than with NSB medium (containing nutrient broth, boric acid, and NaCl as major ingredients). Fecal coliform counts obtained with m-ST by the delayed-incubation membrane filter procedure were higher than counts obtained by the standard immediate incubation. This result suggested that some of the sublethally injured fecal coliforms in natural water samples may have recovered during the incubation period. We propose that m-ST be used in place of m-VFC for the delayed-incubation membrane filter procedure.

Culture Media↗
PubMed1983

Maintenance of the adaptation of skeletal muscle mitochondria to exercise in old rats.

The purpose of this study was to determine whether the adaptive increase in mitochondrial enzymes in skeletal muscle induced by a constant exercise program is altered by aging. Male pathogen-free Long-Evans rats were exercised by means of swimming for 3h/d, 5d/wk beginning at age 6 months and studied at ages 9 and 24 months. The levels of activity of the four mitochondrial enzymes used as indicators of the capacity for aerobic metabolism (citrate synthase, succinate DH, 3-hydroxyacyl-CoA-DH, and 3-ketoacid-CoA-transferase) were significantly increased in epitrochlearis muscle in both the 9-month and 24-month-old swimmers. The increases ranged from approximately 20% for 3-hydroxyacyl-CoA-DH to 50-60% for 3-ketoacid-CoA-transferase. Neither the 24-month-old sedentary rats nor the 24-month-old swimmers had significantly lower muscle enzyme levels than the comparable 9-month-old rats. Thus, it appears that aging does not result in a progressive decline in the capacity of muscle for aerobic metabolism or a progressive impairment in the ability to maintain an increase in muscle mitochondrial enzymes in response to chronic exercise in healthy rats.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1983

A modulatory lipoprotein related to cancer cell inhibition.

Three fractions of lipoprotein were isolated from sera and ascites of cancer-bearing mice by polyanion precipitation and density centrifugation. The cancer modulatory activity of isolated lipoproteins was estimated by means of trypan blue exclusion and cell potassium content. The activity of one of the isolated lipoprotein fractions was to kill cancer cells in vitro with little effect on normal bone marrow cells. This lipoprotein migrated as one band on agarose electrophoresis. After incubating cancer cells with the lipoprotein, the membrane fluidity of the cancer cells was markedly changed (p less than 0.01). The mechanism of modulation may be related to interaction of lipoprotein with plasma membrane of cancer cells.

Animals↗