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Biomedical subjects

H Oguri

Publications and source records attributed to H Oguri.

18 recordsLinked to original sources
PubMed1992

The difference in immunological properties between lymph node metastatic and non-metastatic cell lines of MCA-induced fibrosarcoma of C4W mice.

To pursue the process of lymph node metastasis, i.e, the preferential tumor growth in lymph node, we have established the non-metastatic M2B cell line which was derived from 3-methylcholanthrene-induced fibrosarcoma of C4W mouse and a metastatic cell line, M2BLN-M+ which was obtained from metastatic lymph nodes of irradiated C4W mouse which was subcutaneously implanted with cultured tumor cells, because implanted tumor cells were derived from the spontaneous metastatic lymph node of the parental M2B tumor, but regressed in naive C4W mouse. We examined the characteristics of both tumor cell lines in terms of the immunological cellular interactions. M2BLN-M+ showed unexpectedly to be more susceptible to cytotoxicity of immune effectors (NK cell, macrophage and cytotoxic T lymphocyte) than M2B did. When cultured both tumor cells with these effector cells, the growth inhibition of M2BLN-M+ was greater than that of M2B. The regional lymph node of tumor-bearer, however, showed no effective cytotoxic activity as reported by others. On the contrary, when cultured both tumor cells with non-immune lymph node cells, to be surprised, the proliferation of M2B was markedly suppressed, while that of M2BLN-M+ was slightly inhibited. The lymph node cells of M2B-bearing mice showed stronger cytostatic activity to M2B. The results suggest that the cytostatic activity of lymph node cells will be a pivotal factor, concerning the establishment of lymph node metastasis.

Animals↗
PubMed1991

Suckling stimulates the expression of vasoactive intestinal polypeptide gene in rats.

The effect of suckling on vasoactive intestinal polypeptide (VIP) gene expression in the hypothalami was studied during the postpartum period in rats. Female rats were divided into two groups immediately after delivery. In one group, a mother was housed with 8 pups, and in the other, without any pups. The former group was named S(+) and the latter S(-). On days 0, 3, 6, 9 and 12 after delivery, the mothers were killed by decapitation. Hypothalamic VIP mRNA was measured by RNA dot hybridization. Although the VIP mRNA level showed no significant change after delivery in the S(-) group, VIP mRNA in the S(+) group on days 6, 9 and 12 increased to 1.6, 3.5 and 2.1 times higher than the level observed on day 0, respectively. These results suggest that suckling induces the synthesis of VIP after 6 postpartum days.

Actins↗
PubMed1989

The ontogeny of growth hormone in the human fetal pituitary.

To examine the ontogeny of growth hormone synthesis and secretion in human fetus, growth hormone messenger ribonucleic acid was measured in 11 pituitaries from fetuses of 16 to 27 weeks of gestation by hybridization of cytosol ribonucleic acid with complementary deoxyribonucleic acid labeled with phosphate 32. Pituitary growth hormone content and serum growth hormone, thyroxine, and cortisol concentrations were assessed by radioimmunoassay. Growth hormone messenger ribonucleic acid content in the fetal pituitary increased from the early midtrimester, reaching a level 15.3 times higher at 27 weeks of gestation than the value at 16 weeks. However, growth hormone content in the pituitary showed no evident change during 16 to 21 weeks of gestation and started to increase after 22 weeks. Serum concentration of growth hormone was variable but always greater than 50 ng/ml, and the maximal level was observed at 20 weeks of gestation (141 ng/ml). Although serum thyroxine concentration in the fetuses showed no correlation with pituitary growth hormone content or serum growth hormone concentration, serum concentration of cortisol was correlated positively with growth hormone content in the fetal pituitary. These results suggest that the maturation of the growth hormone synthesis and secretion system in the fetal pituitary occurs after 22 weeks of gestation and that cortisol may play some role in the ontogenesis of growth hormone.

Fetal Blood↗
PubMed1989

Regulation of prolactin gene expression during early pregnancy in rats.

We have shown that administration of estrogen which increases prolactin (PRL) synthesis in the rat may be mediated by an increase in poly [adenosine diphosphate ribose (ADP-ribose)] synthesis. Present investigation was attempted to study whether poly (ADP-ribose) synthesis is involved in rat PRL gene expression during early pregnancy. Anterior pituitaries were obtained on days 0, 2, 4, 6, 8, 10 and 12 of pregnancy (group C). Another group of pregnant rats was given nicotinamide, an inhibitor of poly (ADP-ribose) synthesis twice a day intra-peritoneally from day 0 to the day of sacrifice (group N). Serum estradiol (E2) concentration was determined by radioimmunoassay. PRL mRNA was measured by cytoplasmic dot hybridization using 32P-labeled cDNA. Poly (ADP-ribose) synthesis was assessed by incubating purified nuclei with 14C-nicotinamide adenine dinucleotide. The serum concentration of E2 increased between days 2 and 4, and on day 6 it decreased to the level of day 0. It remained low until day 12. No difference in the serum E2 level was observed in groups C and N. In group C, PRL mRNA increased from day 2 and remained high until day 8. In group C, poly (ADP-ribose) synthesis increased between days 2 and 4, decreased on day 6 to the level of day 0, and thereafter gradually increased until day 10. Administration of nicotinamide abolished the increase in poly (ADP-ribose) synthesis observed in group C during early pregnancy. In group N, the increase in PRL mRNA was completely suppressed. It is suggested that the increase in PRL mRNA in early pregnancy may be mediated by increased poly (ADP-ribose) synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1979

Body surface potential distributions in posterior ventricular pre-excitation.

Waveform of the QRS complex during ventricular pre-excitation is subject to the influence of both the site of pre-excitation and the time of pre-excitation relative to that of excitation via the normal AV path. This paper reports a case in which lead V1 of the electrocardiogram (ECG) could be altered from an R to an rS pattern by the administration of atropine sulfate. The provable mechanism was that of reduced conduction time in the normal AV path with altered time phase of normal excitation and pre-excitation. This mechanism was simulated in experiments on dogs and yielded similar findings. Body surface mapping in both the patient and the dogs provided evidence that pre-excitation could be recognized by that means with varied time phase of normal excitation and pre-excitation. It was demonstrated that the QRS complex of right sided precordial leads could be altered from an R to an rS pattern by altering the time phase of normal excitation and pre-excitation of the posterior ventricular wall. This alteration was related to the degree to which negative potentials on the anterior chest wall due to right ventricular breakthrough of normal activation developed in relation to the time of pre-excitation.

Action Potentials↗
PubMed1978

Computational reconstruction of body surfact isopotential maps in myocardial infarction: comparison between nontransmural and transmural infarction.

The relationship between the lack of electromotive force in myocardial infarction and body surface potential distribution was investigated on maps reconstructed from a simulated heart model and transfer impedance vectors of human torso model. The heart model, a cluster of 3-mm cubic blocks, was stored in the memory of a computer. Transfer impedance vectors between 81 lead points on the human torso model and 392 positions covering ventricular areas in the torso were measure. Body surface potential values were calculated mathematically by summing up scalar products between the electromotive force of the heart model and the measured transfer impedance vectors. Thus, reconstructed maps changed in their patterns with the alternation in lacation and/or extent of infarcted region in the heart model. In particular, the appearance of the abnormal potential minimum, which projects the infarcted region in the heart model onto the torso surface, was characteristic in both transmural and subendocardial infarction. In addition, delayed activation in the intact layer of the epicardium overlying the infarcted region produced a potential maximum on the same place as the abnormal potential minimum appeared previously.

Action Potentials↗
PubMed1978

[Experimental and clinical study of WPW syndrome--detection of preexcitation site through the use of body surface maps (author's transl)].

The purpose of this experimental and clinical study was to evaluate the utility of body surface maps in detecting the preexcitation site of WPW syndrome. By using the electrical bypass tract, the electrocardiographic patterns of WPW syndrome were simulated by the fusion beat between pre- and normal excitation of the in situ canine ventricle. A comparison was made between the body surface and the epicardial maps of the same fusion beat. Throughout the ventricular activation serial body surface maps represented well the activation sequence on the epicardium. The following three points seem to be important for the detection of the preexcitation site of WPW syndrome through the use of body surface maps; 1) the location of the initial minimum, 2) the time of appearance of the voltage concavity (or the saddle) in the right anterior chest wall (in posterior preexcitation), 3) and in addition, the sequential changes in the pattern of positive and negative areas throughout the ventricular activation. In clinical use, body surface maps also localized well the preexcitation sites of the patients with WPW syndrome who underwent the operation.

Adult↗
PubMed1977

Genesis of body surface potential distribution in right bundle branch block.

In order to investigate the specific sites of conduction block in the three types (I, II, III) of right bundle branch block (RBBB) classified by body surface isopotential maps, the simulation of ventricular propagation process and mathematically reconstructed maps were used. Four assumptions were introduced from the results of clinical observations and animal experiments. The maps reconstructed from two of these assumptions, in which the conduction block was placed on the main stem of the right bundle branch, showed two different patterns at late stages of excitation, and these two kinds of map resembled Types I and II in clinical maps, respectively. The maps reconstructed from the other two assumptions, in which the site of the conduction block was located mainly in the Purkinje system of the right ventricular free wall, resembled Type I at the late stage of excitation in one of two assumptions and agreed with Type III through all stages of excitation in other case. Based on the above results, it is speculated that the differences of ranges and degrees of conduction block ascribed to abnormal activation in the Purkinje system of the right ventricular free wall are responsible for the genesis of clinical RBBB map patterns.

Bundle-Branch Block↗
PubMed1977

Body surface potential distribution following the production of right bundle branch block in dogs. Effects of breakthrough and right ventricular excitation on the body surface potentials.

Right bundle branch block (RBBB) was produced in five dogs by incising the main right bundle branch. Body surface isopotential maps of each of these dogs were obtained from 85 thoracic electrocardiograms using a mini-computer technique. In addition, the epicardial activaton process was obtained from the same dog, and were correlated with the map pattern. Following the incision, the following characteristic changes in the map pattern occurred: The ventricular activation was prolonged in RBBB as compared with normal. During the early stage of ventricular excitation, the maximum was shifted leftward due to the activation wavefronts in the left ventricle in contrast to the double septal activation in the control. A localized lower potential area (a concavity) which appears in the middle stage of activation within the anterior positivity as an initial representation of breakthrough was also shifted left-and-downward and delayed in appearance. The sudden change in the potential distribution subsequently observed occurred quite differently. The terminal excitation was characterized by the maximum occurring over the right chest in RBBB in contrast to the left chest in control. These changes in the pattern of the potential distribution were compatible with the changes in the ventricular excitation process. This result may be applied to human RBBB map interpretation.

Action Potentials↗