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Biomedical subjects

A Shigematsu

Publications and source records attributed to A Shigematsu.

At least 127 records · Page 7Linked to original sources
PubMed1987

The carcinogenicity of quinoline and benzoquinolines in newborn CD-1 mice.

The environmental occurrence and mutagenic activity of quinoline and benzoquinolines are well-documented. In this study, the relative carcinogenic activities of quinoline, benzo[f]quinoline, benzo[h]quinoline, and phenanthridine were evaluated in newborn mice. Mice were injected intraperitoneally on the first, eighth, and fifteenth day of life with 0.25, 0.5, and 1.0 mumol of each of these aza-arenes. Quinoline induced a 71% incidence (P less than 0.005) of hepatic tumors among the male mice sacrificed at 52 weeks of age. None of the female mice treated with these aza-arenes developed hepatomas. Among the female mice treated with quinoline there was a significant development of leukemia or lymphoma (P less than 0.05) which was not evident among the female mice in any of the other experimental groups. Benzo[h]quinoline and phenanthridine were not carcinogenic under these assay conditions. Benzo[f]quinoline did induce an increase in the incidence of hepatomas among male mice (19% as compared to 5.9% among controls). This increase, however, was not statistically significant. These data indicate that quinoline has greater carcinogenic potential than any of these isomeric benzoquinolines in newborn mice.

Animals↗
PubMed1986

[Endogenous inhibitory system in pain].

Electrical stimulation of several brain sites produces profound analgesia in humans, and inhibits nocifensor reflexes in animal studies. Responses of the dorsal horn nociceptive neurons evoked by stimulation onto the receptive fields are also inhibited by brain stimulation. These brain sites are Periaqueductal Gray Matter (PAG), Nucleus Raphe Magnus (NRM), Nucleus Reticularis magnocellularis (NRmc), Locus Coeruleus (LC), Lateral Hypothalamus, and others. We have explained in a general way the mechanism of these stimulation produced analgesia. The mechanism of PAG stimulation analgesia is partly due to an activation of serotonin containing neurons which descend from NRM to the spinal dorsal horn and activated by PAG stimulation. Activation of NRM neurons may produce inhibition of the nociceptive neurons of the dorsal horn by the mechanism of direct postsynaptic inhibition. Currently there is no evidence to support the theory of presynaptic inhibition. Endogenous opioid peptides do not play an important role in PAG stimulation analgesia. On the other hand, the mechanism of NRmc or LC stimulation analgesia may be due to an activation of noradrenaline containing neurons which similarly inhibit the dorsal horn nociceptive neurons in the spinal cord. At present, it still remains unknown whether endogenous opioid peptides play an important role in this type of analgesia.

Analgesia↗
PubMed1986

Mucinous adenocarcinoma associated with long-standing fistula in the cecal region.

A patient with mucinous adenocarcinoma associated with long-standing chronic fistula in the cecal region is presented. Association of mucinous carcinoma with chronic fistula seems to occur not infrequently in the anal region, but is extremely rare elsewhere in the large intestine. This is the first report of an occurrence in the cecal region.

Adenocarcinoma, Mucinous↗
PubMed1986

Prediction of subclavian vein location using plain chest radiography.

The relationship between the right subclavian vein and the thoracic inlet below the clavicle was studied by Venography in 72 patients. The area of the thoracic inlet below the clavicle was defined as a radiolucent area surrounded superiorly by the lower border of the clavicle, inferiorly by the inner margin of the first rib and medially by the lateral margin of the manubrium (CRM area). In 10 patients, the subclavian vein was situated below the axis of the clavicle, and the CRM area was large enough to extend near the top of the first rib arch. In 62 patients, the subclavian vein extended above the axis of the clavicle and the CRM area was small or invisible. The existence of a large thoracic inlet below the clavicle (large CRM area which extends near the top of the first rib arch) may be a useful indicator for predicting the low location of the subclavian vein, and may be used to predict or explain venipuncture failure using the standard infraclavicular approach.

Adult↗
PubMed1986

Short-term studies on the in vivo metabolism of N-oxides of nicotine in rats.

This study was designed to examine the in vivo reduction of the N-oxidation products of nicotine metabolism in rats. Male Fischer-344 rats were divided into one control and three experimental groups (n = 20). Each treatment group received either 0.02% trans-nicotine N'-oxide, 0.02% cis-nicotine N'-oxide, or 0.02% nicotine N,N'-dioxide in drinking water for 3 wk. After 7 d of metabolite administration, plasma nicotine levels in the trans-nicotine N'-oxide group rose to twice that of the cis-nicotine N'-oxide or nicotine N,N'-dioxide group. Plasma cotinine [1-methyl-5-(3-pyridinyl)-2-pyrrolidinone] concentrations reached maximum levels during wk 1 in the cis-nicotine N'-oxide and nicotine N,N'-dioxide groups but continued to increase for another 7 d in the trans-nicotine N'-oxide group. At d 15 and again at d 21, rats from each group (n = 10) were placed in metabolism chambers and given 50 ml tap water over a 24-h period. Analysis of urine obtained from a metabolism-chamber study conducted after 15 d of consumption revealed concentrations of nicotine in the trans-nicotine N'-oxide group that were 3 times higher than cis-nicotine N'-oxide-treated animals. Urinary cotinine levels were similar in all three groups. Results from a second chamber study (d 21) showed similar urinary nicotine and cotinine values in all treatment groups. Plasma total triiodothyronine (TT3) concentrations were reduced in all treatment groups during the first week. Plasma total thyronine (TT4) concentrations were reduced (p less than 0.05) in the trans-nicotine N'-oxide and cis-nicotine N'-oxide treatment groups during the first week. Plasma total thyronine (TT4) concentrations cis-nicotine N'-oxide is presented. An analytical method for separation of nicotine, cotinine, and cis- and trans-nicotine N'-oxide, as well as cis- and trans-nicotine N,N'-dioxide, is also outlined.

Age Factors↗
PubMed1985

Clinical evaluation of a newly introduced noninvasive cardiac flow detector (CardioFlo).

Clinical evaluation on a newly-introduced cardiac flow detector (CardioFlo) was made on 6 patients. The correlation between the values obtained from the Swan-Ganz catheter (thermodilution) and the present method was studied. A good correlation (r = 0.94) was demonstrated, which indicates clinical validity of this new method, especially when time is extremely limited as in emergency cases.

Adolescent↗
PubMed1985

Natural history of fundic gland polyposis in patients with familial adenomatosis coli/Gardner's syndrome.

In order to study the natural history of fundic gland polyposis, 23 patients with familial adenomatosis coli/Gardner's syndrome were examined over a follow-up period ranging from 17 mo to 13 yr (average 6 yr). Examinations included gastric radiography and endoscopy with biopsy. Fundic gland polyps were found in 10 individuals. The size and number of polyps varied considerably. During the follow-up period, there was an increase in number or size of polyps, or both, in 5 patients (aged 8-27 yr), a decrease or disappearance in 2 patients (aged 36 and 41 yr), an initial decrease or disappearance followed by a late-occurring increase in 2 patients (aged 28 and 35 yr), In addition, malignant or adenomatous changes of fundic gland polyps were not observed in any patient. Therefore, fundic gland polyposis in patients with familial adenomatosis coli/Gardner's syndrome may appear as early as 8 yr of age. In some patients there is a gradual increase in number and size of polyps, whereas in others, polyp proliferation ceases and polyps may even decrease in number and size. Our findings indicate that the fundic gland polyposis does not require prophylactic surgery and that careful periodic follow-up should suffice.

Adolescent↗
PubMed1985

Evaluation of the effects of cotinine and nicotine-N'-oxides on the development of tumors in rats initiated with N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide.

The effects of cotinine and nicotine-N'-oxides on tumor development in F344 rats initiated with N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide [(FANFT) CAS: 24554-26-5] were evaluated. When rats were 6 weeks old, FANFT in an agar diet was administered for a 6-week period. Subsequently, cotinine, trans-nicotine-N'-oxide, and a mixture of cis-nicotine-N'-oxide and trans-nicotine-N'-oxide in drinking water were given as promoters in concentrations of 0.1, 0.02, and 0.02%, respectively. These nicotine metabolites were offered ad libitum for 78 weeks. Control groups consisted of rats that received tap water with or without prior administration of FANFT. Cotinine, trans-nicotine-N'-oxide, and the mixture of cis- and trans-nicotine-N'-oxides were neither carcinogens nor promoters of urinary bladder tumors in rats initiated with FANFT. A reduced incidence of urinary bladder tumors was observed in FANFT-pretreated animals that also received a mixture of cis- and trans-nicotine-N'-oxides. FANFT administration increased the incidences of mesothelioma of the peritoneum and thyroid tumors. Tumor formation in the tongue and palate observed in FANFT-treated rats was not affected by administration of these nicotine metabolites. There was, however, a significant increase in the incidence of forestomach tumors in rats that were initiated with FANFT and subsequently received either trans-nicotine-N'-oxide or a mixture of cis- and trans-nicotine-N'-oxides.

Animals↗
PubMed1985

The effects of catechol on the urinary bladder of rats treated with N-butyl-N-(4-hydroxybutyl)nitrosamine.

The effect of catechol on the development of urinary bladder tumors in Fischer rats treated with N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) was studied. A solution of 0.05% catechol and 0.001% BBN was administered in the drinking water ad libitum for 78 weeks. The urinary bladders were then removed and examined microscopically. No statistically significant difference was observed between the experimental group receiving 0.001% BBN with 0.05% catechol and animals receiving 0.001% BBN alone with respect to the incidence of hyperplasia, papilloma, or carcinoma of the urinary bladder. Animals receiving 0.05% catechol alone in the drinking water had no macroscopic or microscopic lesions significantly different from those in control animals receiving tap water. Analyses of the urine of animals receiving catechol in their drinking water indicated that greater than 99% of the catechol present was in the form of either glucuronide or sulfate conjugates. In a second bioassay, the potential cocarcinogenicity of catechol, administered together with BBN, was explored by direct instillation into the urinary bladder. The development of calculi and possible infections of the urinary tract within all groups of treated animals suggests that this bioassay technique for cocarcinogenicity is of questionable value. These data show that catechol at the dose and mode of administration employed in this study did not affect the epithelium of the urinary bladder or enhance the carcinogenic activity of BBN.

Animals↗
PubMed1985

Gardner's syndrome associated with carcinoma of the duodenal bulb: report of a case.

A 49-year-old woman with Gardner's syndrome, who underwent total proctocolectomy in 1982, was found to have a cancer of the duodenal bulb. Subsequently, resection of the stomach and duodenal bulb was performed in 1983. The surgical specimen showed an ulcerating tumor in the duodenal bulb which was a moderately differentiated adenocarcinoma histologically. Multiple adenomas were present in the gastric antrum and the duodenum. Duodenal cancer so far reported has been mostly confined to the periampullary region, and cancer of the duodenal bulb associated with familial polyposis coli has not been reported.

Adenocarcinoma↗
PubMed1984

Tumor-initiating activity of quinoline and methylated quinolines on the skin of SENCAR mice.

Quinoline and all 7 positional isomers of methylquinoline were assayed for tumor-initiating activity on the skin of SENCAR female mice with promotion by tetradecanoyl phorbol acetate. The total initiation dose of either quinoline or the isomeric methylquinolines was 7.5 mg per mouse. Quinoline induced tumors in 53% of the mice (0.73 tumors per animal). While 2-, 3-, 5- and 7-methylquinoline did not exhibit significant tumorigenic activity in this assay, 4-methylquinoline induced tumors in 45% of the mice (0.90 tumors per animal). 8-Methylquinoline induced tumors in 45% of the mice (0.66 tumors per animal).

Animals↗
PubMed1984

Whole-body distribution of 11C-(4)-L-aspartic acid in rats.

Enzymatic synthesis of 11C-(4)-L-aspartic acid was undertaken using commercially available wheat germ phosphoenolpyruvate carboxylase. Whole-body distribution of the radioactive compound in rats showed higher accumulation in the salivary gland, glandular stomach and the pancreas, as well as in the lungs. Within 60 minutes after intravenous injection of 11C-(4)-L-aspartic acid, about 60% is removed as 11CO2 by expiration, indicating that the carbon atom at the fourth position of the radioactive compound is easily subjected to decarboxylation.

Animals↗
PubMed1984

[Analysis of gastric biopsy specimens group III by a revised group classification].

A revised group classification of histology in gastric biopsy specimens was recently proposed by the Japanese Research Society For Gastric Cancer. The specimens judged as Group III by the revised classification contained; adenoma that used to be judged as Group III by the former classification, lesions difficult to distinguish between adenoma and carcinoma, lesions difficult to distinguish between atypical regenerative epithelium and carcinoma, and so on. Pathologists are requested to describe whether the lesion is adenoma or not and to consult with clinicians about the lesion in order to reduce the possibility that a case of well-differentiated adenocarcinoma is misdiagnosed as Group III by the revised classification.

Adenocarcinoma↗
PubMed1983

Spectral studies on the effect of a new steroidal anesthetic agent alphadione on rat hepatic microsomes.

Alphadione, a steroidal anesthetic formulation containing alphaxalone (3 alpha-hydroxy-5 alpha-pregnane-11, 20-dione) and alphadolone acetate (21-acetoxy-3 alpha-hydoroxy-5 alpha-pregnane-11, 20-dione) in polyoxyethylated castor oil (Cremophor EL) owes its short duration of action to rapid metabolic transformation rather than the redistribution into the body fat. Treatment of rats with alphadione (1 ml/kg; intraperitoneal route) induced an increase in the cytochrome P-450 content of the liver. The difference spectra were obtained only when alphadione or alphaxalone was added to the liver microsomal suspension while neither alphadolone acetate nor Cremophor EL induced any spectral changes. The spectral dissociation constant (Ks) for alphaxalone was 2.5 X 10(-3) mM suggesting that hydroxylation of alphaxalone is a cytochrome P-450 dependent reaction.

Anesthetics↗