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Biomedical subjects

Y Sakuma

Publications and source records attributed to Y Sakuma.

At least 91 records · Page 5Linked to original sources
PubMed1997

Two different hard palate closure techniques in two-stage palatoplasty: effects on velopharyngeal closure and articulation.

Two different hard palate closure techniques, in two-stage palatoplasty, was evaluated in 12 patients. The lip and soft palate were closed at 3 to 7 months of age. The patients were then divided into two groups of six and the hard palate closed at 17 to 23 months of age, either by a vomer flap (VF) with a skin graft (Osada's two-stage palatoplasty) in the VF group, or by the push-back (PB) procedure of the mucoperiosteal flap in the PB group. Velopharyngeal closure (VPC) during a gag reflex before and after hard palate closure, and the articulation of these patients after closure, were evaluated and compared between the two groups. Regarding VPC before hard palate closure, three "Poor" and three "Borderline" outcomes were noted in each group. We conclude that, by introducing the pharyngeal flap, the patients in the VF group obtained good articulation, actually comparable to that in the PB group.

Articulation Disorders↗
PubMed1996

In situ hybridization for two differentially expressed GnRH genes following estrogen and triiodothyronine treatment in the brains of juvenile tilapia (cichlid).

Using in situ hybridization, messenger RNAs for gonadotropin-releasing hormone (GnRH) were seen distributed differently in the brains of 40-day-old juvenile tilapia Oreochromis mossambicus. While salmon-GnRH mRNA was localized in the nucleus olfactoretinalis (terminal nerve ganglia), chicken II-GnRH mRNA mRNA was observed in the midbrain nucleus. Various concentrations (0.1-10 mg) of estradiol benzoate and triiodothyronine, given over a 24 h period, had no effects on mRNA levels of salmon- and chicken II-GnRH. Analysis of variance indicated significantly higher levels of salmon- but not chicken II-GnRH mRNA in larger (> 1.5 mm) versus smaller (1.3 mm) brains, among juveniles of the same age and same genetic brood. Thus, salmon-GnRH neurons in the nucleus olfactoretinalis display greater variance depending on the body mass. Since reproductively active tilapia differ with respect to body size at sexual maturation, therefore, besides the age and treatment effects, body size should be taken into consideration.

Animals↗
PubMed1996

A quantitative method for the determination of plasmid copy number in recombinant yeast.

A method is described for the determination of plasmid copy number (PCN) in the recombinant yeast Saccharomyces cerevisiae producing human coagulation Factor XIII. Southern hybridization of restriction endonuclease HindIII-digested total DNA from yeast transformant with the 32P-labelled URA3 gene as a probe detected two band: one corresponding to the chromosomal URA3 gene and the other corresponding to the recombinant plasmid. Thus, the present method using the genomic URA3 gene as an internal standard allowed an estimation of both the plasmid and the standard simultaneously. Since haploid yeast cells harbour one copy of genomic URA3 gene, the PCN can be determined as the ratio of the amount of plasmid to that of genomic URA3 gene. A linear relationship between the determined PCN and the plasmid content was observed ranging from 0.3 to 200 ng. The method is reproducible and independent of the extraction efficiency for the recombinant plasmid. The present method was successfully used to analyzed the PCN of a centromere-based plasmid YCp50 (= 2.7) and of a 2 microns-based plasmid pEMBLyex4 (= 112).

DNA, Recombinant↗
PubMed1996

Exogenous estrogen acts differently on production of estrogen receptor in the preoptic area and the mediobasal hypothalamic nuclei in the newborn rat.

Expression of the estrogen receptor (ER) in the preoptic area (POA) and the mediobasal hypothalamus (MBH) in newborn female rats was studied by immunohistochemistry (IHC) and in situ hybridization histochemistry (ISHH). The number of ER immunoreactive (ER-IR) cells decreased and expression of ER mRNA was suppressed in the arcuate (ARH) and the ventromedial (VMH) hypothalamic nuclei by daily injections of estradiol benzoate (EB) for ten consecutive days. In contrast, in the POA, expression of ER mRNA was not suppressed by EB treatment, while the ER immunoreactivity and the number of ER-IR cells was decreased by EB treatment. Results of quantification of ER mRNA by reverse transcription-polymerase chain reaction correlated well with results from ISHH: that is, ER mRNA expression decreased in the MBH but not in the POA. Thus, estrogen affects ER gene expression differently in these two brain regions.

Animals↗
PubMed1996

Quasi-steadiness approximation for the single-compartment urea kinetic model (SCUKM).

Using SCUKM, we constructed recurrence formulae expressing weekly pre- and post-dialysis urea levels. Then we mathematically derived simple methods to estimate Kt/V0 and the urea generation rate (G) per unit urea distribution space post-dialysis (V0), which only required the measurement of pre- (C) and post-dialytic blood urea concentrations (C0) of a single hemodialytic session (two-point method). Underlying fundamental assumptions were: (i) patients receive weekly scheduled hemodialysis; (ii) the ultrafiltration rate, intradialytic urea generation, interdialytic water increase rate, and residual renal function are small enough to be retained only as the leading term in the formulae. In the derivation, we proved relations: C = f(Kt/V0)G/V0, and C0 = g(Kt/V0)G/V0, which state that both C and C0 are directly proportional to G/V0, and that the proportional constants are functions of Kt/V0. Errors of the formulae were also checked to make the limitation of the approximations clear. The present formulae exactly reproduced Kt/V0 and G/V0 of virtual patients strictly obeying the SCUKM in a computer simulated model. Using the blood urea nitrogen concentration data of 20 actual patients, we compared our method with the usual three-point method and obtained substantial correlations between them (r = 1.00 for Kt/V0, r = 0.98 for G/V0). Finally, we proposed convenient and easily calculable new formulae, which give sufficiently accurate Kt/V0 and G/V0.

Blood Urea Nitrogen↗
PubMed1996

Role of urinary arginine vasopressin in the sodium excretion in patients with chronic renal failure.

Patients with chronic renal failure show almost equal levels of sodium excreted in the urine as healthy subjects through an increase of the fractional excretion sodium (FE(Na)). The mechanisms of this adaptation, however, are unknown. Recently, urinary arginine vasopressin (AVP) has been shown to inhibit the antidiuretic action of plasma AVP in the collecting ducts of rabbits and rats. In this article, the roles of plasma and urinary AVP are examined with other hormones in the sodium excretion of 57 patients with chronic renal disease. The fractional excretion of AVP, plasma atrial natriuretic peptide (ANP) and endothelin-1 (ET-1), urinary ET-1, and FE(ET-1) correlated with the decrease of creatinine clearance (Ccr). Multiple and stepwise regression analyses showed that FE(AVP) is the major dependent determinant for FE(Na) (adjusted r2 = 0.78). These results suggest that the increase of AVP excretion per remaining nephron could be a cause of the increase of FE(Na) in patients with renal failure. Although plasma AVP works as an antidiuretic hormone, urinary AVP serves as an intrinsic diuretic, especially in patients with chronic renal failure.

Adolescent↗
PubMed1996

Plasma cholesterol reducing effect of FR129169, a novel acyl-CoA:cholesterol acyltransferase inhibitor, in the rat.

FR129169 (FR) (N-(1,2-diphenylethyl)-2-octyloxyphenylacetamide) has been found to inhibit acyl-CoA:cholesterol acyltransferase (ACAT) activities in intestinal microsomes of rats and rabbits and the liver homogenate of rats with IC50 values of around 1.0 x 10(-7) M. The inhibitory activity was 2-3 times more potent than that of CI 976 (CI). When FR in a dose of 10 mg/kg/day was administered as a dietary admixture, plasma cholesterol levels were normalized in rats fed a high cholesterol diet, but lower doses of FR had no effect. Similar results were obtained in the rats treated with CI. The ex vivo study where hepatic ACAT activity was measured after oral dosing of the two inhibitors revealed that ACAT activity was significantly reduced in rats treated with FR in a dose of 10 mg/kg/day, while CI reduced the activity at lower doses such as 0.1 and 1 mg/kg/day. Since FR was not orally absorbed, it is speculated that the inhibitory activity of FR on hepatic ACAT in the ex vivo study results from the reduction of plasma cholesterol levels. These results suggest that FR exerted cholesterol-lowering activity mainly through inhibition of intestinal ACAT activity. The significance of intestinal ACAT inhibition by FR for therapeutic treatment of hypercholesterolemia is discussed.

Acetamides↗
PubMed1996

[Two cases of localized organizing pneumonia simulating lung cancer].

Localized organizing pneumonia is one of the benign conditions which must be differentiated from lung cancer. We have reported two cases of localized organizing pneumonia diagnosed by histological study of surgical specimens. Two cases were initially regarded as lung cancer, because the symptoms of respiratory tract infection were not remarkable and initial roentgenographic findings revealed a tumor-like shadow. Diagnostic thoracoscopy which was less invasive upon a patient were very useful in differentiating organizing pneumonia from lung cancer.

Adult↗
PubMed1995

Beneficial effects of a novel anti-hypoxemic agent, TEI-7322, on bleomycin-induced experimental hypoxemia in rats.

Almitrine bismesylate is known to be an anti-hypoxemic agent that acts via the enhancement of hypoxic pulmonary vasoconstriction. However, screening for this class of compounds has been minimal, owing, in part, to a lack of convenient hypoxemic models in small animals. The present study was designed to establish a convenient model of hypoxemia induced by bleomycin and to evaluate anti-hypoxemic agents including a newly synthesized compound. TEI-7322, 2-allylamino-4-tert-butyl-amino-7-methyl-7H-pyrrolo[2,3- d]pyrimidine hydrochloride by using this model. Bleomycin was intratracheally instilled into rats. After 3 weeks, the arterial blood gas pressures were monitored in the animals in the conscious state. Then, prednisolone, doxapram, almitrine or TEI-7322 was administered to the bleomycin-treated rats to monitor changes in arterial blood gas pressures. Bleomycin-treated rats showed a decrease in the arterial blood O2 pressure (PaO2). The blood CO2 pressure (PaCO2) increased, along with an increase in the alveolar-arterial oxygen difference (AaDO2). These blood gas pressures in bleomycin-treated rats were not affected by treatment with prednisolone. Doxapram decreased the PaCO2 but did not change the PaO2. However, administration of almitrine or TEI-7322 significantly improved the PaO2 of bleomycin-treated rats with a decrease in the PaCO2. In conclusion, (1) bleomycin-induced lung injury causes hypoxemia in rats, probably resulting from ventilation-perfusion inequality; thus this model may be useful for evaluating anti-hypoxemic agents; and (2) TEI-7322, as well as almitrine, showed anti-hypoxemic effects in this model with different properties from those of doxapram, possibly due to improvement of ventilation-perfusion inequality, indicating that TEI-7322 may be a potent candidate for the treatment of hypoxemia.

Almitrine↗
PubMed1995

Stria terminalis conveys a facilitatory estrogen effect on female rat lordosis reflex.

The effects of bilateral cut of the stria terminalis (ST) on the dosage of estradiol benzoate (EB) needed to induce the lordosis reflex in the ovariectomized female rat were examined. Seven different doses ranging 0.5-20 micrograms were given s.c. in oil, daily for 2 days in a counterbalanced order, at 3-week intervals. The log dose-response relationship was linear in both ST-cut and sham-operated control rats. A significantly larger dose of 9.3 +/- 1.4 (mean +/- SEM) micrograms/day of EB was needed in the ST-cut rats (n = 8) to obtain a 50% lordosis quotient than in the controls (n = 7), in which a 2.0 +/- 0.3 micrograms/day dose had a similar effect. The slope of the dose-effect curve was significantly steeper in the ST-cut rats than in the controls. The ST mediates facilitatory effects of estrogen on the lordosis reflex that originate presumably in the amygdala.

Animals↗
PubMed1995

Lipidosis of the dorsal root ganglia in rats treated with an almitrine metabolite.

Toxic effects of a detriazinyl metabolite of almitrine (DTMA) were evaluated in rats and on cultured rat macrophages. In rats daily treated with DTMA for 16 weeks, spastic gaits with heel-lifting appeared, and lamellated and/or crystalloid bodies formed in sensory neurons, satellite cells, Schwann cells, and vascular endothelial cells of the dorsal root ganglia. The lysosomal lamellated bodies, which were not induced by almitrine, were produced also in cultured rat macrophages exposed to over 1 x 10(-5) M DTMA.

Administration, Oral↗
PubMed1995

Diametrically opposite effects of estrogen on the excitability of female rat medial and lateral preoptic neurons with axons to the midbrain locomotor region.

Electrical stimulation of the midbrain locomotor region (MLR) in 76 ovariectomized, urethan-anesthetized female rats elicited antidromic action potentials in 252 preoptic neurons. Thresholds and refractory periods for the activation ranged from 60 to 1550 microA and 1.3 to 5.0 ms, respectively. The probability distribution for the peak-to-peak amplitude (2-14 mV) or the overall duration (0.7-4.4 ms) was bell-shaped, whereas that for the latency (1.8-33.5 ms) was distinctively bimodal with a division at 12.0 ms. Two groups of preoptic neurons of a similar soma size therefore project to the MLR presumably via different routes. In 121 neurons with latencies < or = 12.0 ms, estrogen lowered the antidromic activation thresholds (nested analysis of variance, P < 0.02), but 131 neurons with latencies > 12.0 ms had their thresholds increased (P < 0.005) and refractory periods prolonged (P < 0.02) by estrogen. Even though both overlapped in part, many potentials with the shorter latencies were recorded from the medial part of the lateral preoptic area (mLPO), lateral to the recording sites of the longer-latency potentials in the medial preoptic area (MPO). The observed antagonistic effects of estrogen on the two groups of preoptic neurons with axons to the MLR may contribute to increased locomotor activity in female rats in estrus.

Action Potentials↗
PubMed1995

Enzymatic basis for the accumulation of Lewis(b) antigen in uterine endometrial cancer.

In order to clarify the mechanism of the abnormal expression of Lewis(b) antigen, which was specific for uterine endometrial cancer tissue, the activities of alpha 1-->2fucosyltransferase, alpha 1-->3fucosyltransferase, and alpha 1-->4fucosyltransferase in normal endometrial tissues and uterine endometrial cancer tissues were determined. Further, an immunocytochemical study of the expression of blood group-related carbohydrate antigens in 6 cultured cell lines derived from various gynecologic malignant tumors was performed and the alpha 1-->2fucosyltransferase, alpha 1-->3fucosyltransferase, and alpha 1-->4fucosyltransferase activities of these cell lines were determined. Compared with normal endometrium, uterine endometrial cancer tissues showed significantly higher values of alpha 1-->2fucosyltransferase, alpha 1-->3fucosyltransferase, and alpha 1-->4fucosyltransferase activities. The specifically strong expression of type I carbohydrate chains, particularly the Lewis(b) antigen, was recognized in cultured cell lines derived from uterine endometrial cancer. Compared with those cell lines derived from uterine cervical cancer and ovarian cancer, the cultured cell lines derived from uterine endometrial cancer showed higher activities of alpha 1-->2fucosyltransferase and alpha 1-->4fucosyltransferase, which are enzymes related to the synthesis of Lewis(b) antigen. The cell lines derived from uterine endometrial cancer showed specifically high values of alpha 1-->4fucosyltransferase activity. These results suggest that the alpha 1-->2fucosyltransferase and alpha 1-->4fucosyltransferase activities, especially the alpha 1-->4fucosyltransferase activity, contribute to the abnormal expression of the Lewisb antigen in uterine endometrial cancer.

Antigens, Neoplasm↗
PubMed1995

[Abnormal expression of carbohydrate chain and its mechanism in endometrial cancer].

An increased rate of expression of Lewis group antigens, particularly Lewisb antigen, was observed in endometrial cancers compared with its expression in normal endometria. In order to elucidate the expression mechanism of Lewisb antigen in endometrial cancer, the level of fucosyltransferase (FT) was examined. The levels of alpha 1-2FT alpha 1-3FT and alpha 1-4FT were higher in endometrial cancer than those in normal endometrium. Endometrial cancer with a poor prognosis tended to react poorly to anti-endometrial cancer monoclonal antibody designated MSN-1, suggesting the possibility that the reactivity to MSN-1 is useful as a new prognostic factor for endometrial cancer. Cells of uterine endometrial cancer cell line SNG-II were classified into two groups according to their reactivity with MSN-1, whose antigen recognized is mainly Lewisb antigen. Using these classified cells of endometrial cancer cell line, it has revealed that the cells which strongly express H type antigen have more tendency to attach to endothelial cells and to cause metastasis than the cells which strongly express Lewisb antigen.

Biomarkers, Tumor↗
PubMed1994

Axon-sparing lesion of the preoptic area enhances receptivity and diminishes proceptivity among components of female rat sexual behavior.

Stereotaxic infusion of ibotenic acid deleted neurons in the medial preoptic area (POA) in the ovariectomized female rats. A well-circumscribed lesion was infiltrated by astrocytes; local axons of passage were spared. Following estrogen priming and progesterone supplement, the females with the lesion had higher lordosis quotients than the vehicle-infused controls, when males successfully mounted them. On the other hand, the treatment did not induce solicitation in females with the lesion nor reduced their rejection of male partners. Meanwhile, gradual and persistent suppression of the lordosis reflex followed electrical stimulation through electrodes placed in the POA lesion. Except that the females with the POA lesion needed less estrogen to obtain comparable prestimulation quotients with the controls, the lesioned and control animals responded similarly to the stimulation. Because an adjunct neural transection dorsal to the POA lesion abolished the stimulus-bound suppression of lordosis, the effect was due to the activation of axons of passage that presumably descend from the septum. It is concluded that the POA is the major target for estrogen in eliciting proceptive behavior; local POA neurons as well as septal efferents appear to inhibit the lordosis reflex, the principal receptive component in female rat sexual behavior.

Animals↗