Calcium entry in rat parotid acinar cells.
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Animals↗
Biomedical subjects
Y Hiramatsu
Publications and source records attributed to Y Hiramatsu.
Elevation of cytosolic [Ca2+] due to intracellular Ca2+ release retards carbachol stimulation of divalent cation entry in rat parotid gland acinar cells.
This study examines the activation of divalent cation entry into rat parotid gland acinar cells by using Mn2+ as a Ca2+ surrogate cation. Following muscarinic-cholinergic stimulation of dispersed parotid acini with carbachol (10 microM), the onset of internal Ca2+ release (cytosolic [Ca2+], [Ca2+]i, increase) and the stimulation of Mn2+ entry (increase in fura2 quenching) are not simultaneously detected. [Ca2+]i elevation, due to intracellular release, is detected almost immediately following carbachol addition and peak [Ca2+]i increase occurs at 6.0 +/- 0.8 sec. However, there is an interval (apparent lag) between carbachol addition and the detection of stimulated Mn2+ entry. This apparent lag is decreased from 26 +/- 3.1 sec to 9.2 +/- 1.5 sec when external Mn2+ ([Mn2+]0) is increased from 12.5 to 500 microM. It is not decreased further with increase in [Mn2+]0 from 500 microM to 1 mM (9.8 +/- 2.1 sec), although both intracellular free Mn2+ and [Mn2+-fura2]/[fura2] increase. Thus, at [Mn2+]0 < 500 microM, the observed lag time is partially due to a limitation in the magnitude of Mn2+ entry. Furthermore, neither peak [Ca2+]i nor the time required to reach peak [Ca2+]i is significantly altered by [Mn2+]0 (12.5 microM to 1 mM). At every [Mn2+]0 tested (i.e., 12.5 microM-1 mM), the apparent lag is significantly greater than the time required to reach peak [Ca2+]i. However, when carbachol stimulation of the [Ca2+]i increase is attenuated by loading the acini with the Ca2+ chelator, 2-bis(O-aminophenoxy)ethane-N,N,N',N'-tetraacetate (BAPTA), there is no detectable lag in carbachol stimulation of Mn2+ entry (with 1 mM [Mn2+]0). Importantly, in BAPTA-loaded acini, carbachol stimulates Mn2+ entry via depletion of the internal Ca2+ pool and not via direct activation of other divalent cation entry mechanisms. Based on these results, we suggest that the apparent lag in the detection of carbachol stimulation of Mn2+ entry into parotid acinar cells is due to a retardation of Mn2+ entry by the initial increase in [Ca2+]i, due to internal release, which most likely occurs proximate to the site of divalent cation entry.
Androstenedione↗
Characterization of polyphosphoinositide-specific phospholipase C in rat parotid gland membranes.
Hydrolysis of exogenously added, [3H]inositol-labeled, phosphatidylinositol 4,5-bisphosphate (PIP2) by rat parotid membranes was increased, dose-dependently, by the muscarinic cholinergic agonist carbamylcholine (carbachol) in the presence of guanosine 5'-O-thiotriphosphate (GTP gamma S). The stimulation was inhibited by atropine and guanosine 5'-O-thiodiphosphate (GDP beta S). GTP gamma S alone stimulated PIP2 hydrolysis, with half-maximal activation at 0.1 microM. This was inhibited by GDP beta S but not by atropine. Agonist stimulation of PIP2 hydrolysis was dependent on the presence of lipids (phosphatidylserine:phosphatidylethanolamine:PIP2 = 1:1:1). When PIP2 was added as micelles with detergent (sodium deoxycholate) only, basal hydrolysis was elevated, thus decreasing the relative stimulation by GTP gamma S and carbachol. The water-soluble hydrolysis products formed under either condition were 1,4,5-inositol trisphosphate, 1,4-inositol bisphosphate, and cyclic inositol trisphosphate. Hydrolysis of exogenous phosphatidylinositol (PI) was also stimulated by carbachol in the presence of GTP gamma S but the extent of PI hydrolysis was 44-fold lower than PIP2 hydrolysis. When [Ca2+] in the medium was increased from 100 nM to 1 microM, basal hydrolysis of both PI and PIP2 increased (9.3- and 19.2-fold, respectively). However, levels of basal and stimulated PIP2 hydrolysis were higher (37.9- and 29.6-fold, respectively) than those of PI hydrolysis. Antibodies (both polyclonal and monoclonal) raised against phospholipase C (PLC beta 1) from bovine brain did not react with any component in either rat parotid membranes or cytosol, although a reactivity was detected in rat brain membranes. A monoclonal antibody against bovine brain PLC gamma 1 detected a approximately 150-kDa protein only in the parotid cytosol, while antisera against bovine brain PLC delta 1 enzyme showed no reactivity with parotid membranes or cytosol. Together, these observations suggest that while there appears to be a protein similar to bovine brain PLC gamma 1 in parotid gland cytosol, the PLC which mediates PIP2 hydrolysis in rat parotid membranes and can be regulated by the muscarinic receptor via a G-protein is distinct from the well-characterized PLC enzymes gamma 1, delta 1, and beta 1.
Animals↗
5-Methylurapidil may discriminate between alpha 1-adrenoceptors with a high affinity for WB4101 in rat lung.
The alpha 1-adrenoceptors of rat lung with a high affinity for [3H]-prazosin were subdivided into two populations (high and low affinity sites) by WB4101 and 5-methylurapidil but the proportions were different between both drugs. After pretreatment with chlorethylclonidine, WB4101 recognized only high affinity sites, while 5-methylurapidil still detected high and low affinity sites. These results indicate that alpha 1-adrenoceptors with a high affinity for WB4101 are not homogeneous in the rat lung, suggesting the possible existence of a new alpha 1-adrenoceptor subtype in addition to alpha 1A and alpha 1B subtypes.
Adrenergic alpha-Antagonists↗
Preliminary experience with gadolinium-enhanced dynamic MR imaging for uterine neoplasms.
Usefulness of gadopentetate dimeglumine in magnetic resonance (MR) imaging of uterine neoplasms was evaluated in 53 patients with endometrial carcinoma and 15 patients with cervical carcinoma. T1- and T2-weighted MR images were obtained before the contrast material was administered. After a bolus injection of gadopentetate dimeglumine, dynamic MR images were acquired, followed by static T1-weighted images. Gadolinium-enhanced MR images revealed relatively small endometrial carcinomas in the uterine cavity as high signal intensity in four cases and invasion of the myometrium as low signal intensity in 20 cases. In eight cases, endometrial tumors showed irregular, early enhancement compared with that of the myometrium on dynamic images; these cases were associated with poor prognosis. Tumor extension into the lower part of the uterus, parametrium, and paracervical fat was well seen on enhanced images in cases of cervical carcinoma. The authors believe that gadolinium-enhanced MR imaging will prove helpful in the staging of uterine neoplasms.
Adenocarcinoma↗
Urinary and plasma epidermal growth factor levels are decreased in neonates with intrauterine growth retardation and in their mothers.
Epidermal growth factor (EGF) concentrations in urine and plasma samples collected from pregnant women and neonates were measured by RIA. The EGF concentration of the first voided urine was higher in appropriate-for-date (AFD) neonates (33.9 +/- 23.0 ng/mg creatinine) than in those with intrauterine growth retardation (IUGR; 23.5 +/- 7.7 ng/mg creatinine, p less than 0.05) and heavy-for-date (19.8 +/- 5.2 ng/mg creatinine, p less than 0.05) neonates. The urinary EGF concentration of pregnant women showed no marked changes throughout pregnancy. Urinary EGF concentrations of women with AFD fetuses (45.9 +/- 31.2 ng/mg creatinine) did not differ significantly from those of women with diabetes (39.9 +/- 26.8 ng/mg creatinine) or women with multiple fetuses (44.6 +/- 30.6 ng/mg creatinine). However, women with IUGR fetuses showed lower urinary EGF concentrations (13.8 +/- 7.4 ng/mg creatinine, p less than 0.05) than women with AFD fetuses. Maternal and fetal platelet-poor plasma EGF concentrations at delivery were lower in the IUGR group (mother: 2.62 +/- 0.38 ng/ml, fetus: 2.16 +/- 0.07 ng/ml, respectively, p less than 0.05 and p less than 0.005) than in the AFD group (mother: 3.34 +/- 0.64 ng/ml, fetus: 3.24 +/- 0.93 ng/ml). In the IUGR group, the EGF concentration in fetal blood was always lower than that in maternal blood (p less than 0.05), although the AFD groups showed no such difference. These data suggest that EGF levels are closely related to fetal growth.
Birth Weight↗
Developmental changes of glutamate dehydrogenase activity in rat liver mitochondria and its enhancement by branched-chain amino acids.
The developmental changes of glutamate dehydrogenase activity in the fetal and neonatal rat liver were investigated, as well as the effects of branched-chain amino acids on this enzyme. Hepatic glutamate dehydrogenase activity showed a marked increase at the end of the fetal period and peaked on the 5th day of neonate at approximately 3 times higher than the adult level. Glutamate dehydrogenase was activated by leucine, isoleucine, and valine in this order when they were added to isolated intact liver mitochondria in vitro. The enhancement of enzyme activity was more marked in fetal rats than in adults. In contrast, when branched-chain amino acids were added after disrupting the mitochondrial membrane by sonication, only leucine slightly activated glutamate dehydrogenase, while isoleucine and valine slightly inhibited its activity. Our findings suggest that glutamate may be actively synthesized in the developing rat liver mitochondria and then transaminated to other nonessential amino acids for protein synthesis, and that increased intramitochondrial branched-chain amino acid concentrations may enhance glutamate dehydrogenase activity. This anabolic metabolism will contribute to the fetal growth and development.
Amino Acids, Branched-Chain↗
Development changes of polyamine biosynthesis in rat liver.
To investigate the role of polyamine metabolism in fetal development, we determined the hepatic polyamine content and the activity of enzymes related to polyamine metabolism in fetal, newborn and adult rats. In the fetuses, spermidine was detected at the highest level, followed by spermine and then putrescine. Putrescine and spermidine levels were higher in the fetuses than in adult rats, while the spermine level was significantly lower in the fetuses. The activities of the enzymes investigated were also higher in the fetuses than in adult rats. These findings indicate that polyamine synthesis was enhanced in the fetal liver, and that degradation of spermidine via spermidine N1-acetyltransferase contributes to the increase in putrescine levels. Thus, our study suggests that an increase in putrescine is important for fetal growth and that putrescine per se has a significant role in fetal cellular proliferation.
Acetyltransferases↗
[Influences of hypercholesterolemia on the vessel function of isolated rat thoracic aorta].
Mature male rats (SD strain, 8-week-old) were fed with a normal diet or a high cholesterol diet (HC: 1.5% cholesterol and 0.5% Na cholate in the normal diet) up to 8 weeks, and we examined how the vascular function level of the isolated thoracic aorta and the histological figures of some tissues including the aorta would change. 1) The contracting reactivity to phenylephrine (Phe, 10 microM) and the relaxing reactivity to acetylcholine (1 microM) measured thereafter remained unchanged during the period of aging and were not influenced by HC-feeding. The addition of L-arginine (Arg, 100 microM) did not affect the results. 2) The ability of the aorta to release NO and to relax, which was evaluated as the extent of the endothelium-dependent potentiation by NG-monomethyl-L-arginine (NMA) of the Phe contraction, did not change by HC-feeding up to 4 weeks, but appears to be attenuated after 8-week feeding. 3) The EC50 of NMA for the potentiation estimated without the addition of Arg remained unchanged, while the one in the presence of Arg gradually increased with aging but not with HC-feeding. 4) The histopathological study of the aorta and other tissues failed to detect any notable atherogenic changes in any of the HC-fed groups. The results indicate that under the experimental conditions employed, HC-feeding would not develop any significant atherogenic histopathological changes in the endothelium-smooth muscle preparation, but may induce some dysfunction in the NO-release mediated and auto-regulatory function of the vascular tone.
Acetylcholine↗
Osteoclastic features of multinucleated giant cells responding to synthetic hydroxyapatite implanted in rat jaw bone.
Multinucleated giant cells (MGCs) that responded to synthetic hydroxyapatite (HAP) implanted in rat mandibles were studied with electron microscopy. HAP used in this study sintered at 200 degrees C (HAP200) and at 125 degrees C (HAP1250) after the synthesis by a wet method. One to three weeks after the intraosseous implantation of HAP, MGCs responding to HAP200 had not only well-developed ruffled border and the clear zone but well-developed perinuclear Golgi complex, many mitochondria and vesicles in their cytoplasms. MGCs responding to HAP1250 had the clear zone, but not the ruffled border although they showed similar cytoplasmic features to those of MGCs responding to HAP200. They merely extended short slender cytoplasmic processes to HAP1250. These results suggest that although osteoclast-like MGCs respond to HAP implanted in the bone, the development of the ruffled border-clear zone system depends on physicochemical properties of HAP.
Animals↗
Ultra-high-resolution scanning electron microscopy of vaccinia virus and its recombinant carrying the gag gene of human immunodeficiency virus type 1.
FL cells infected with vaccinia virus or its recombinant carrying the gag gene of human immunodeficiency virus type 1 (HIV-1) were examined by ultra-high-resolution scanning electron microscopy. Virions, whether located extracellularly or intracellularly, had a brick-shaped or watermelon appearance as a whole. Extracellular virions observed on the surface of infected cells had variable surface ultrastructures depending on the manner in which particular virions were wrapped in cell membranes. Most of the intracellular naked virions adherent to the inner face of cell surface membranes clearly exhibited ridgy, rod-shaped or globular surface structures on their surface. HIV-like particles with a diameter of about 100 nm and virions of vaccinia virus were both observed distinctly on the surface of FL cells infected with the recombinant virus.
Amnion↗
[A case of abdominal aortic pseudoaneurysm due to Salmonella enteritidis septicemia].
A 66-year-old man suffering from high fever and abdominal pain was diagnosed as abdominal aortic pseudoaneurysm due to Salmonella enteritidis septicemia. After complete remission of infection with the antibiotic therapy, we performed a replacement of abdominal aorta with a prosthetic graft. Infection parameters are normal 5 months postoperatively. Although Salmonella septicemia is a serious disorder, it is not a rare infection recently as compromised host increases more. Rapid diagnosis, adequate antibiotic therapy and surgical treatment are essential for successful result of Salmonella aortic aneurysm.
Aged↗
[A case report of poststernotomy mediastinitis treated with the pectoralis major muscle flap after protracted wound irrigation].
A 8-year-old boy developed mediastinitis after direct closure of atrial septal defect. Methicillin-resistant Staphylococcus aureus (MRSA) was detected from the wound. Intermittent wound irrigation with povidone-iodine solution and vancomycin solution was protracted for two months. After the remission of MRSA infection, implantation of pectoralis major muscle flap was performed. Without recurrence of infection the wound was healed completely. Although pectoralis major muscle flap is an effective method of choice for mediastinitis, an appropriate timing of enforcing this method should be investigated hereafter.
Child↗
[Congenital lobar emphysema successfully treated by right upper lobectomy at five hours after delivery: a case report].
Lobar emphysema is a rare disease and one of the causes of respiratory disturbance in the newborn and infancy. A case report is presented and compared with related data in the literature in Japan. Maternal echographic findings indicated the cystic lung disease of the fetus. The cystic space was punctured and aspirated three times. The baby was delivered by caesarean section after having taken sufficient precaution to prevent respiratory failure. Since the baby developed dyspnea gradually, at five hours following the delivery, right upper lobectomy was performed and the major symptoms were eliminated. The pathological diagnosis was congenital lobar emphysema and the etiology was concluded to be bronchiectasis.
Cystic Adenomatoid Malformation of Lung, Congenita↗
Characterization of high affinity GTPase activity correlated to beta-adrenergic receptor stimulation of adenylyl cyclase in rat parotid membranes.
beta-Adrenergic receptor stimulation of adenylyl cyclase involves the activation of a GTP-binding regulatory protein (G-protein, termed here Gs). Inactivation of this G-protein is associated with the hydrolysis of bound GTP by an intrinsic high affinity GTPase activity. In the present study, we have characterized the GTPase activity in a Gs-enriched rat parotid gland membrane fraction. Two GTPase activities were resolved; a high affinity GTPase activity displaying Michaelis-Menten kinetics with increasing concentrations of GTP, and a low affinity GTPase activity which increased linearly with GTP concentrations up to 10 mM. The beta-adrenergic agonist isoproterenol (10 microM) increased the Vmax of the high affinity GTPase component approx. 50% from 90 to 140 pmol/mg protein per min, but did not change its Km value (approximately 450 nM). Isoproterenol also stimulated adenylyl cyclase activity in parotid membranes both in the absence or presence of GTP. In the presence of a non-hydrolyzable GTP analogue, guanosine 5'-(3-O-thio)triphosphate (GTP gamma S), isoproterenol increased cAMP formation to the same extent as that observed with AlF-4. Cholera toxin treatment of parotid membranes led to the ADP-ribosylation of two proteins (approximately 45 and 51 kDa). Cholera toxin also specifically decreased the high affinity GTPase activity in membranes and increased cAMP formation induced by GTP in the absence or the presence of isoproterenol. These data demonstrate that the high affinity GTPase characterized here is the 'turn-off' step for the adenylyl cyclase activation seen following beta-adrenergic stimulation of rat parotid glands.
Adenylyl Cyclases↗
Surgical treatment for poor-risk patients with carcinoma of the esophagus.
During the period between 1979 and 1988, 145 patients with cancer of the esophagus were admitted to our department. They were examined for the preoperative risk factors associated with multiple organ function and classified into three groups according to the risk score. Special attention was paid to postoperative pulmonary complications, mortality and the long term results of surgery in the poor-risk patients and the findings analyzed in reference to the operative procedures. The resection rate for the poor-risk group was 41 per cent, however, esophagectomy was only able to be combined with a right thoracotomy and abdominal approach in 26 per cent of the patients in this group. Postoperative pulmonary complications developed in 64 per cent of the poor-risk patients who underwent a transthoracic esophagectomy and in only 25 per cent of those who received a transhiatal esophagectomy, although there was no significant difference in the overall survival rate between these two subgroups. The present observations therefore raised the possibility that transhiatal esophagectomy may improve the results of surgical treatment for poor-risk patients with esophageal cancer.
Age Factors↗
Subchronic oral toxicity of glyoxal via drinking water in rats.
The subchronic oral toxicity of glyoxal via drinking water and the effect on in vivo protein synthesis in tissues following a single treatment with this substance were assessed in Sprague-Dawley male rats. Animals received drinking water containing glyoxal levels of 2000, 4000, and 6000 mg/liter ad libitum for 30, 60, and 90 days in Phase I. In Phase II, the high-dose and control-1 groups fed the diet ad libitum, and a diet-limited control-2 group given the same amount of diet as consumed by the high-dose group were maintained for 90 and 180 days. The study designs included observations of clinical signs, body weights, major organ weights, gross and histopathological examinations, serum clinical chemistry, and biochemical examinations such as glyoxalase activity and glutathione content in selected tissues. Body weight gain and organ weights significantly decreased with dosage. Although consumption of food and water was also depressed in the exposed group, the reduction of body weight gain was greater in the high-dose group than in the diet-limited control 2 group. Histopathological examinations revealed only a slight papillary change in the kidneys from the high-dose group at both 90 and 180 days terminations in Phase II. The induction of both glyoxalase I and II was observed in liver and erythrocytes at 30-day termination of the exposed groups. Serum enzyme and protein levels were significantly reduced by the mid- and/or high-dose exposures. With a single oral high-dose treatment of glyoxal, a great decline in the incorporation of L-[3H]leucine was shown particularly in the liver, and this probably led in part to a reduction in the serum protein levels in rats following subchronic exposure to glyoxal. These data indicated an overall low degree of systemic toxicity to rats exposed subchronically to glyoxal via drinking water.
Animals↗
[Biochemical and histopathological studies on a mouse brain ischemic model induced by bilateral carotid artery occlusion: comparison with the carbon monoxide inhalation method and other ischemic or anoxic models].
Bilateral occlusion of the carotid arteries (BCAO) killed 52% of the male ddY mice (N = 86) and 77% of the ICR mice (N = 96) within 10 min, and the mean survival time of the ddY strain recorded for the 10 min was significantly longer than the time of the ICR strain. Among animals that survived longer than 1 hr after BCAO, some (5 of ddY and 3 of ICR) were able to survive for more than 24 hr. All of the neurobehavioral and histopathological signs developed by BCAO and in most cases followed by death were found to be also inducible by unilateral occlusion alone, although this was in a small fraction of mice. The brain levels of ATP, glucose and acetylcholine significantly decreased in mice that died within 10 min after BCAO, while none of these changes were detectable in mice surviving BCAO for 1 hr, just as in mice that died by carbon monoxide or ether inhalation. The results obtained herein indicate that mice may not be homogeneous in the functional level of the collateral route of blood supply to the brain tissue and/or in the sensitivity toward the ischemia-inducible lethality.
Acetylcholine↗