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Biomedical subjects

M Shimada

Publications and source records attributed to M Shimada.

At least 811 records · Page 45Linked to original sources
PubMed1984

Distribution of 35S-taurine in rat neonates and adults. A whole-body autoradiographic study.

The distribution of 35S-taurine in rat neonates and adults was investigated by wholy -body autoradiography. The neonates (4-day-old) were frozen in dry-ice hexane at 30 min, 1, 3 and 6 h after an intraperitoneal injection of 35S-taurine, whereas survival intervals for adult rats were 1 and 3 h. Whole-sagittal sections of the frozen rat, obtained by using a cryostat microtome were dried in situ and autoradiographed. In rat neonates and adults, 35S-taurine was mainly accumulated in the renal cortex, urine, feces, liver, eye (lens, vitreous fluid, retina), hypophysis, thymus, adrenal glands, nasal mucous membrane, salivary glands, gastric mucosa, small and large intestinal mucosa, choroid plexus, myocardium and sebaceous glands. In the rat neonate, such regions as the olfactory bulb, cerebrum, and cerebellum showed relatively high optical density.

Aging↗
PubMed1984

Effects of 3-acetylpyridine on the adrenal medulla of the mouse.

In the present work, the effects of 3-acetylpyridine (3-AP) on the adrenal medulla were investigated for biochemical and morphological changes. Adrenaline- and noradrenaline-storing cells treated with 3-AP one day previously had lost almost all their granules. A large number of lipoid droplets appeared in the cytoplasm. At the same time, the concentrations of adrenaline and noradrenaline cells were significantly decreased below control values (P less than 0.01). However, these significant changes were ameliorated 19 days after 3-AP treatment. Morphologically and biochemically, the adrenaline- and noradrenaline-storing cells had recovered completely at 35 days.

Adrenal Medulla↗
PubMed1984

Agenesis of the corpus callosum in ddN strain mouse associated with unusual facial appearance (flat-face).

In the course of an experiment involving brother-sister matings between ddN strain mice, mice occurred with an unusual facial appearance (flat-face). Subsequently, 4 mice with flat-face were bred from the litters of the second birth (ca. 10% frequency). This flat-face was assumed to be the result of a malformed short nose, hypoplastic maxilla and mandible, and hypertelorism. These 4 flat-face mice exhibited no significant delays in growth, motor ability or the development of learning ability. Histologically, they were all characterized by an almost total absence of callosal fibers and the presence of abnormal longitudinal neuromatous bundles. Therefore, the flat-face mice may be useful as experimental animals for brain research, as one can easily judge that they lack the corpus callosum from the facial appearance.

Abnormalities, Multiple↗
PubMed1984

Effects of 3-acetylpyridine on local cerebral glucose utilization.

Local cerebral glucose utilization was observed in mice treated with 3-acetylpyridine (3-AP), one of the nicotinamide antagonists. This drug resulted in loss of pyramidal cells and gliosis restricted almost exclusively to Spielmeyer's resistant sector (area CA3) in the dorsal hippocampus. On the other hand, the most striking feature in the autoradiographic observations was that optical density in the impaired CA3 region of the dorsal hippocampus was significantly increased (P less than 0.01). Therefore, when the 2-deoxyglucose method is employed under pathological conditions, one must pay attention to these glial reactions.

Animals↗
PubMed1984

Precipitates found around Schistosoma haematobium eggs from human urine prior to circumoval precipitin test.

Schistosoma haematobium eggs were recovered in urine from schoolchildren in Mwachinga Village, Kwale District, Kenya. The surface of the eggs showed a pattern similar to that observed in a circumoval precipitin (COP) test. Observed precipitates were removed by treatment of the eggs with pepsin, but were not affected by trypsin. Similar precipitates occurred after incubating the pepsin-treated eggs with urine supernatants from the same children. Attempts were made to identify the components that might contribute to observed bleb (precipitate) formation. The fluorescent antibody test revealed both IgG and IgM in the precipitate, while urine examination by immunodiffusion revealed IgG, IgM, IgA and C3. These components probably participated in the bleb formation. This possibility seemed more likely because of the presence of anti-egg antibodies in the immunoglobulins identified in the urine, and agrees well with the expected activity of pepsin on these immunoglobulins. These results, therefore, suggest that S. haematobium eggs recovered in urine contain precipitates formed mainly by immunoglobulins; it is necessary to treat such eggs with pepsin before carrying out a COP test. The relevance of these findings to the immunodiagnosis of Schistosomiasis haematobium in man is discussed.

Adolescent↗
PubMed1984

Neonatal testosterone imprinting of hepatic microsomal drug metabolism and a male-specific form of cytochrome P-450 in the rat.

The effects of neonatal castration and treatment with testosterone on sex-specific forms of cytochrome P-450, namely P-450-male and P-450-female, were studied. Neonatal castration of male rats resulted in a change in the population of forms of cytochrome P-450. Castration 1 day after birth abolished the synthesis of P-450-male and stimulated the synthesis of P-450-female. The decrease in the amount of P-450-male as well as the activities of drug metabolizing enzymes was partially reversed by administration of testosterone after castration.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1984

Induction of physical dependence on codeine in the rat by drug-admixed food ingestion.

The developmental process of physical dependence on codeine has been explored in rats treated with codeine-admixed food (0.5 mg/g food) during 1 to 7 days. In rats treated with codeine for more than 2 days, body weight loss was markedly observed after the abrupt codeine withdrawal. The intensity and time course of body weight loss increased according to the duration of codeine treatment. After the codeine withdrawal, behavioral signs such as diarrhea, ptosis and vocalization were observed. In the naloxone-precipitated withdrawal test, rats treated with codeine for 1 day manifested a loss of body weight after naloxone challenge, and the intensity of body weight loss increased according to the duration of codeine treatment. After naloxone injection, the codeine-treated rats showed abnormal behaviors such as diarrhea, ptosis, teeth chattering , salivation, body shakes, vocalization, nose bleed, irritability, lacrimation and writhing. The total score, evaluated by the ranking system for precipitated withdrawal behaviors, was correlated with the duration of codeine treatment. These results suggest that naloxone-precipitated withdrawal signs are powerful in comparison with that after codeine withdrawal, and the weight loss is a common index for quantitative assessment of physical dependence on narcotics in the natural and naloxone-precipitated withdrawal tests. It is concluded that the drug-admixed food ingestion method has the advantage of rapidly inducing a high degree of physical dependence on codeine.

Animals↗
PubMed1984

Specificity of four forms of cytochrome P-450 in the metabolic activation of several aromatic amines and benzo[a]pyrene.

The involvement of four forms of cytochrome P-450 in the activation of the promutagens, 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), 2-amino-6-methyl-dipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1), 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-aminofluorene and 4-aminobiphenyl has been investigated using a Salmonella test system. A high-spin form, P-448 II-a, catalysed the activation of IQ and Glu-P-1 28 and 12 times faster, respectively, than a low-spin form, P-448 II-d, whereas benzo[a]pyrene was metabolized to the phenols 60 times faster by P-448 II-d than P-448 II-a. Both P-448 II-a and P-448 II-d were highly active in the activation of Trp-P-2 and 2-aminofluorene. Treatment of CDF1 mice with polychlorinated biphenyls (PCB) increased the microsomal-activating ability for the promutagens in various degrees. More than a ten-fold increase was observed with Trp-P-2, while the increase was only two-fold with IQ. No sex-related difference was observed for the hepatic microsomal activating ability of male and female CDF1 mice for Trp-P-2, Glu-P-1 or IQ. These results indicate that more than two forms of cytochrome P-450, which are inducible by treatment with PCB or 3-methylcholanthrene, mediate the metabolic activation of heteroaromatic amines in rats and mice.

Amines↗
PubMed1984

Effects of acupuncture anesthesia on the pituitary gland.

The skin pain threshold was elevated significantly by weak and nonstressful acupuncture stimulation. Although an analgesic effect was obtained by acupuncture stimulation, the beta-E, ACTH, GH and TSH levels were not changed. These findings indicate that these hormone levels were not necessarily related to the skin pain threshold elevation. It is concluded therefore that an analgesic effect was induced without involving the pituitary gland by the weak acupuncture stimulation employed in our study. However, the magnitude of the stimulation may determine whether or not an analgesic effect is mediated by the pituitary gland. The possibility remains that strong acupuncture stimulation produces stress-induced analgesia (SIA). Further detailed research should be attempted.

Acupuncture Therapy↗
PubMed1984

[Surgical treatment of pulmonary atresia (PA) and critical pulmonary stenosis (PS) with intact ventricular septum (IVS)].

Patients with PA: IVS and critical PS: IVS tend to have hypoplastic right ventricles and tricuspid valves. There is a large range of hypoplasia, but the relationship between the size of the right ventricle cavity and the size of tricuspid valve ring were found to be statistically significant. Pulmonary valvotomy alone is usually not adequate for the first stage operation and a systemic-pulmonary shunt procedure often become necessary. Use of PGE1 improved the overall clinical prognosis of these patients. The appropriate operative method for the second stage operation should be determined by measuring right ventricle volume and evaluating the degree of hypoplasia of the right ventricle, tricuspid valve and pulmonary artery. In three patients with right ventricle and tricuspid hypoplasia, we performed the Glenn procedure in addition to right ventricle outflow reconstruction and obtained good surgical results.

Child, Preschool↗
PubMed1984

[Comparison of three methods of inducing physical dependence to morphine in rats using short-term medication].

A comparison of several methods for developing physical dependence to morphine was made. Male Sprague-Dawley rats were treated with morphine-admixed food (drug-admixed food, DAF; 0.5 and 1 mg/g food), morphine slow release emulsion (SRE; 75, 100 and 150 mg/kg) and morphine (75 mg) pellets. In the SRE and pellet methods, the typical signs of morphine toxicity, such as catatonia, exophthalmos and shallow respiratory movements, were observed 15-20 min after the treatment and these signs were maintained for 14-18 hr. In rats treated with SRE and pellets, plasma morphine levels reached a maximum 1 day after the morphine treatment, and subsequently decreased, while plasma morphine levels in rats treated with DAF increased treatment period-dependently. Withdrawal signs precipitated by naloxone (3 mg/kg, sc) in rats treated with DAF, SRE and pellets were characterized by loss of body weight, shaking, vocalization, diarrhea, ptosis, tooth-chattering, nose bleed, salivation and lacrimation. Naloxone-precipitated withdrawal signs reached a maximum 1-2 days after treatment with SRE and pellets, and were correlated with the duration of DAF treatment. Rats treated with DAF, SRE (150 and 225 mg/kg) and pellets for 3 days, manifested loss of body weight, diarrhea etc. after the morphine withdrawal. Maximum body weight loss in each group was 7-10% at 1-2 days after the morphine withdrawal. It was thus, concluded that physical dependence on morphine can be induced rapidly by these three methods. However, the SRE and pellet methods induced morphine toxicity and it was difficult to maintain physical dependence on morphine in these rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Learning deficits on avoidance task and hippocampal lesions in area CA3 following intraperitoneal administration of 3-acetylpyridine.

Young adult mice of the ddN-F26 strain were given a single intraperitoneal injection of 3-acetylpyridine (3-AP) at a dosage of 200 mg/kg body weight. Two weeks after this treatment, learning on avoidance task was tested with a training apparatus called a jump-box. Each mouse was subjected to 30 trials of training per week for 3 or 4 weeks. Contrasted to untreated mice, the mean performance of the 3-AP-treated mice on avoidance training was significantly reduced in every weekly training session. However, since the learning scores of individual 3-AP-treated mice were highly varied, these mice were divided into several groups according to the characteristics of their learning patterns in order to analyze the relationships between learning ability and brain damage. It was found that there was a close association between the rate of learning deficits and the degree of destruction of the pyramidal cells in area CA3 of the hippocampus in mice treated with 3-AP. The present data suggest that the area CA3 neurons play an important role on the acquisition of avoidance task and memory formation.

Animals↗