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Biomedical subjects

M Saeki

Publications and source records attributed to M Saeki.

At least 73 records · Page 4Linked to original sources
PubMed1996

Effect of morphine on secretion of amylase from isolated parotid acini.

The effect of morphine on amylase secretion was studied in isolated rat parotid acinar cells. It was found that aluminum fluoride (AlCl3/NaF) and dibutyryl-cyclic AMP but not by cyclic AMP, enhanced amylase secretion. Cyclic AMP was effective in enhancing secretion following permeabilization of cells with alpha-toxin. Following treatment of cells with alpha-toxin, both GTP and GTP-gamma-S also enhanced secretion. Morphine reduced AlCl3/NaF- or GTP-induced secretion of amylase, but was without effect on GTP-gamma-S-induced secretion. Photoaffinity labeling by the use of [32P] 4-azidoanilido GTP revealed its incorporation into 43 kDa and 31 kDa proteins. Incorporation was further enhanced with AlCl3/NaF. Morphine reduced labeling of the 43 kDa protein. Immunoblot analysis identified the 43 kDa GTP binding protein as Gs. When [gamma 32P] GTP was preloaded into permeabilized acinar cells and its hydrolysis measured, morphine stimulated and AlCl3/NaF inhibited GTPase activity. These results suggested the involvement of Gs in secretion of amylase. Furthermore, morphine reduced secretion of amylase by stimulating GTPase activity and by reducing the incorporation of GTP into Gs.

Affinity Labels↗
PubMed1996

Cone ERGs to flash trains: the antagonism of a later flash.

The human cone electroretinogram (ERG) to flash trains and double flashes at different interflash intervals was studied. A double ganzfeld stimulator was used in which computer controlled flashes were presented independently in the presence of strong rod saturating backgrounds. Corneal ERGs were examined at different frequencies of flash train presentations. Flash trains with individual flashes of high frequency (100 Hz) simulate a cone ERG to light pulses of long duration by producing a corneal positive off-response (d-wave) time locked to the cessation of the train. A second flash can reduce and delay the cone b-wave produced by a first flash. This effect is maximal when the second flash occurs 10-12 msec later. There is an antagonistic mechanism in the cone system of the retina which can catch and reduce the cone b-wave produced by an earlier flash.

Adult↗
PubMed1996

[Portal hypertension after successful hepatic portoenterostomy in biliary atresia].

Sixty percent of 139 patients with biliary atresia who underwent hepatic portoenterostomy (Kasai operation) from 1965 to 1994 became jaundice-free after the operation. Portal hypertension, which was confirmed by endoscopic observation of esophageal varices and/or thrombocytopenia (less than 100 x 10(3)/mm3), developed in 50% of unicteric long-term survivors. Esophageal varix was found initially between 11 months and 5 years of age in more than 70% of these portal hypertensive patients. On the contrary, thrombocytopenia developed at 6 years or older age in 63% of the patients. The incidence of portal hypertension was significantly lower in the patients whose serum bilirubin decreased less than 2mg/dl at 3 months after surgery than in the patients whose bilirubin stayed over 2mg/dl at the same postoperative time. Furthermore, re-do operation related significantly to the incidence of portal hypertension in jaundice-disappeared patients. Prophylactic endoscopic injection sclerotherapy and/or variceal ligation were sufficiently effective in the management of esophageal varices. Partial splenic embolization as well as splenectomy seems to be a treatment of choice for hypersplenism.

Adolescent↗
PubMed1996

[A case of malignant esophageal stenosis with esophagobronchial fistula treated with a covered wallstent].

A polyurethane-covered Wallstent was used for a esophagus cancer patient with malignant esophageal stenosis associated with esophagobronchial fistula. Stent placement was successfully performed with no procedure related-complications. Following the procedure the patient could eat a normal diet. The insertion of a polyurethane-covered Wallstent is a safe and effective treatment for malignant esophageal stenosis with esophagobronchial fistula.

Bronchial Fistula↗
PubMed1995

Effects of 15-deoxyspergualin on experimental autoimmune giant cell myocarditis of the rat.

BACKGROUND: The benefits of immunosuppressive therapy for human myocarditis are controversial. The effects of a new immunosuppressant agent, 15-deoxyspergualin (DSG), on rats with experimental autoimmune myocarditis (EAM), an animal model of human giant cell myocarditis, were examined. METHODS AND RESULTS: Lewis rats were immunized with cardiac myosin in Freund's complete adjuvant on day 0. In the first experiment, the effective doses of DSG required to prevent EAM were investigated. Rats were placed into one of five groups: the control group (A) was administered saline from days 1 to 10; group B, 0.3 mg/kg per day of DSG; group C, 1.0 mg/kg per day of DSG; group D, 3.0 mg/kg per day of DSG, and group E, 10.0 mg/kg per day of DSG. Rats were killed on day 28. The heart weight/body weight ratios of the rats of groups D and E were significantly lower than that of the control group. Macroscopic and microscopic scores for myocarditis decreased in groups D and E. In the next experiment, the effects of delayed administration of DSG in preventing autoimmune myocarditis were studied. Two groups of rats received 3.0 and 10.0 mg/kg per day of DSG from days 6 to 15, respectively. Two other groups of rats received the same doses of DSG from days 11 to 20. No preventive effect of delayed DSG treatment was observed. The effects of long-term, delayed initiation therapy then were evaluated. Rats were administered 10.0 mg/kg per day of DSG from days 6 to 25. The heart weight/body weight ratio and macroscopic and microscopic scores of the rats so treated significantly decreased compared with the controls. CONCLUSIONS: It was demonstrated that DSG can prevent the development of cardiac myosin-induced autoimmune myocarditis.

Animals↗
PubMed1995

An ultrastructural study on experimental autoimmune myocarditis with special reference to effector cells.

The previously described animal model of autoimmune myocarditis induced by immunization of Lewis rats with cardiac myosin was investigated pathologically, ultrastructurally and immunohistologically. Cardiac dendritic cells and infiltrating macrophages were dominantly encamped at the front of the myocarditis. The macrophages accompanied by neutrophils infested cardiocytes, forming rosette figures as a sign of active cardiocytolysis. The dendritic cells reached into intact muscle at a short distance from the inflammation. T cells, the most important candidate for effector cells in this animal model, were generally found at a distance from active muscle necrosis.

Animals↗
PubMed1995

[The use of high concentration ferric ammonium citrate (FAC) solution as a negative bowel contrast agent: application in MR cholangiography].

Ferric ammonium citrate (FAC) can be used as a negative contrast agent on T2- weighted images, with the use of a high concentration resulting in a significant T2 shortening effect. Ten healthy volunteers underwent MR cholangiography (MRC) using Turbo Spin Echo. High-concentration FAC was administered at a normal dosage, but was diluted in a smaller amount of water than usual. Although all precontrast images showed high intensity intestinal fluid, which aggravated visualization of the bile duct, all postcontrast images obtained 6 to 14 minutes after administration showed blackening out of the fluid, improving the overall image quality of MRC.

Adult↗
PubMed1995

[High concentration ferric ammonium citrate (FAC) solution as a negative bowel contrast agent].

Various concentrations of ferric ammonium citrate (FAC) solution were scanned with conventional SE, Turbo SE (TSE) and STIR sequences on a 0.5-T MR unit. High-concentration FAC solution showed significant signal loss on T2-weighted images. Signal loss was more prominent on heavily T2-weighted images with longer TR/TE using the TSE sequence. T1-weighted images did not show significant signal loss even with high-concentration solution. On STIR images, remarkable signal loss occurred at twice the concentration that had a T1 value similar to fat. We concluded that high-concentration FAC solution may employ as a negative contrast agent in upper abdominal MR imaging.

Abdomen↗
PubMed1995

[Ultrasonography of pediatric right lower abdominal pain: correlation with clinical and pathological results].

Right lower abdominal pain is a common problem in the pediatric population. Ultrasonography (US) is a well-accepted imaging modality in the clinical management of this problem. One hundred and six consecutive pediatric patients with right lower abdominal pain were prospectively evaluated. There were 54 boys and 52 girls, with ages ranging from 3 to 15 years (mean: 9.9 years). Final diagnoses were established based on pathological findings or clinical follow-up. US had sensitivity of 90%, specificity of 98%, and accuracy of 94% in the diagnosis of acute appendicitis. Among all true negative cases (n = 55), there was a variety of US findings other than appendiceal abnormality in 21 cases including intestinal and/or mesenteric (n = 19), gallbladder (n = 1), and ovarian (n = 1) abnormalities. All 21 cases were managed medically without complication. We conclude that US of pediatric right lower abdominal pain is a reliable imaging modality not only for the diagnosis of surgical cases but for eliminating the unexpected surgical intervention.

Abdominal Pain↗
PubMed1995

[31P-MR spectroscopy of bone and soft tissue lesions].

We studied 24 patients with bone and soft tissue lesions using 31P-MR spectroscopy (MRS). On image selected in vivo spectroscopy (ISIS) localized spectra, spectroscopic parameters were calculated: PME/noise ratio, gamma NTP/noise ratio, PME/gamma NTP and total metabolite signals (TMS). PME/noise, PME/gamma NTP and TMS were higher in malignant lesions than in benign ones. We set the criterion for malignancy as follows: PME/noise > 2.0 and gamma NTP/noise > 2.0 and PME/gamma NTP > 1.0. The accuracy of this criterion was 0.91 for malignant lesions and 1.0 for benign lesions. In six malignant tumors, MR spectra were obtained before and after chemotherapy. They were compared with the degree of tissue degeneration evaluated on pathological specimens. TMS after chemotherapy were markedly reduced in 3 cases. TMS seemed to reflect the degeneration of tumors. It could be said that MRS is a useful tool in differentiating from benign tumor lesions malignant bone or soft tissue lesions and in monitoring the effect of chemotherapy.

Adolescent↗
PubMed1994

Sacroperineal anorectoplasty using intraoperative ultrasonography: evaluation by computed tomography.

A new operative technique that uses ultrasonography during sacroperineal or sacroabdominoperineal anorectoplasty was performed on seven patients with an intermediate or high anorectal malformation. Ultrasonography was used for the purpose of making a pull-through tunnel under visual guidance. The results of this technique were evaluated by computed tomography scanning to find the anatomic position of the pulled-through rectum in relation to the anal sphincter muscle. Postoperative computed tomography scans showed that the rectum was correctly placed in the center of the sphincter muscle in all patients.

Fistula↗
PubMed1994

Altered production of nerve growth factor in aganglionic intestines.

Nerve growth factor (NGF), a target-derived neurotrophic molecule, is required specifically by sympathetic and dorsal root ganglion cells for their survival and maturation during embryonic and early postnatal development. In the present study, the NGF expression was studied both at the protein and mRNA level in normal and aganglionic intestines of Piebald-strain mice and also in 10 human specimens using immunohistochemical and reverse transcriptase polymerase chain reaction (RT-PCR) techniques. In the aganglionic intestines of the mice, immunoreactive NGF was found on the giant nerve fibers in the submucosal layer, but not found in the mucosal layer. In the mRNA study, the signal for NGFmRNA was less intense in the aganglionic rectum of the congenitally megacolonic mice than in the rectum of the normal mice. In contrast, the distal dilated colon of the congenitally megacolonic mice had a more intense signal for NGFmRNA than did the colon of normal mice. The results obtained from human specimens were compatible with the findings in the Piebald mice; the distal colons harvested from the patients with Hirschsprung's disease (or its allied disease) had a uniformly more intense signal for NGFmRNA than did the normal colons. The results of this study may indicate that NGF production is altered in the aganglionic intestines and also in the "transitional zone" in Hirschsprung's disease. The altered production of NGF may be useful in increasing the accuracy of diagnosis of Hirschsprung's disease.

Animals↗
PubMed1994

Primary chemotherapy for children with rhabdomyosarcoma of the 'special pelvic' sites: is preservation of the bladder possible?

Twenty-one children with rhabdomyosarcoma involving the "special pelvic" sites, defined as such occurring in the bladder, prostate, vagina and uterus, were treated with primary surgery between 1969 and 1977, and with primary chemotherapy beginning in 1978. Among 11 patients in the latter group who were placed in Clinical Group III (according to the classification of the US Intergroup Rhabdomyosarcoma Study (IRS), six showed partial response (PR) and underwent tumorectomy by radical surgery an average of 6 months after the start of treatment, and three showed complete response (CR) and were treated with further chemotherapy in the hope that cystectomy could be avoided. However, in the latter group, the tumor recurred (39 months, 35 months, and 27 months later), and all eventually underwent total cystectomy. Seven of the nine long-term survivors underwent total cystectomy and have premanent urinary-cutaneous stomas. Two had tumor-free bladders, but function was impaired in one because of the effect of irradiation. Normal function was preserved in only one patient in the series, whose tumor was located at the dome of the bladder. To preserve bladder function in children with rhabdomyosarcoma in these sites, more effective forms of chemotherapy will be required.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1994

Reproducibility of magnetic resonance spectroscopy in patients undergoing dialysis and evaluation of the therapeutic response of tumors.

RATIONALE AND OBJECTIVES: The reproducibility of repeated magnetic resonance (MR) spectroscopy was studied in patients undergoing dialysis and treatment of a variety of malignant tumors. METHODS: Localized MR spectra were obtained using a 1.5-T system by image-selected in vivo spectroscopy. Total metabolite signal was integrated between phosphomonoester and beta-adenosine triphosphate resonance. We termed this measurement AREA. RESULTS: Intrapatient variability was evaluated on repeated thigh muscle spectroscopy for 10 patients. Sequential spectra of 10 malignant tumors of the extremities were analyzed and compared with the histology of surgical specimens in seven patients. Intrapatient variability in AREA was calculated as 14.0%. The extent of necrosis and AREA ratio (definition: AREA post-therapy/AREA pretherapy) were as follows; 6.1% in > 90% necrosis, 43% in 50% to 90% necrosis, and 79% in < 50% necrosis. CONCLUSIONS: Localized MR spectra are fairly reproducible and may relate to treatment efficacy.

Adolescent↗
PubMed1994

Electrophysiological studies on light damage in the mouse retina after sodium iodate injection.

Acute experimental retinal degeneration was induced in 3-month-old mice with sodium iodate (NaIO3) injection to investigate the effect of bright light with electroretinography (ERG). Eight C 57 black male mice were anesthetized. The ERG was recorded before and 24 h after the injection of NaIO3. Next, only one eye of each mouse was exposed to a bright light of 3.0 x 10(4) lx white light for 30 min. Ten hours later, ERGs of both the light-exposed and the unexposed eye were recorded. The amplitudes and peak latencies of the a wave and b wave were measured. The ERG was recorded as both eyes were exposed to stimulating flashes that were given in an increasing order of 0.6 log unit steps from the dimmest flash to produce a detectable ERG. The ERG from the light-exposed eye showed a distinctly elevated threshold (approx 2.0 log), while the contralateral unexposed eye did not. The peak latencies of both waves were significantly prolonged by exposure to light. In conclusion, light exposure affected ERG thresholds in mice with experimentally induced acute retinal degeneration.

Animals↗
PubMed1994

Rat dilated cardiomyopathy after autoimmune giant cell myocarditis.

One of the possible causes of dilated cardiomyopathy is considered to be a sequel to myocarditis. Two mechanisms have been proposed in the process of progression of myocarditis into dilated cardiomyopathy: one is a persistent viral infection, and the other is an autoimmune myocardial injury. To clarify the possible part played by the autoimmune mechanism in the process, using an animal model, we investigated whether autoimmune myocarditis, exclusively not related to viral infection, might develop into dilated cardiomyopathy. Experimental autoimmune myocarditis was elicited in Lewis rats by immunization with cardiac myosin fraction. Rats of the control group were immunized with ovalbumin. The clinical course was observed over 4 months. Six rats from the myosin-immunized group died during the acute phase and the healing phase, and all those rats had severe myocarditis. All rats that survived until the end of the study showed enlarged and discolored hearts. Aneurysmal changes were observed in the right ventricle during thoracotomy. The ratio of heart weight to body weight of the myosin-immunized group was significantly higher than that of the control group (3.36 +/- 0.49 versus 2.69 +/- 0.06 g/kg, respectively; P < .005). The lengths of the anterior interventricular fissure and the posterior interventricular fissure of the hearts of the myosin-immunized group were significantly longer than those of the control group. The external diameter of the left ventricle of the myosin-immunized group was also significantly larger than that of the control group. Diffuse myocardial muscle loss and replacement fibrosis were the prominent histological findings of the rats of the myosin-immunized group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Tissue residues of sulfadimethoxine following dietary administration to broiler-chickens.

Broilers were divided into four groups and the first group served as the control. The second, third and fourth groups were given feed containing 25, 50 and 100 mg/kg of sulfadimethoxine (SDM), respectively, for 21 days, and thereafter each group received the SDM free feed. On certain days during the experiment period, three broilers in each group were sacrificed and tissues, including blood, heart, liver, spleen, gizzard, thigh muscle, breast muscle and fat, were collected and residual SDM were determined by HPLC. Two days after withdrawal, SDM in each tissue had decreased to below the detection limit of 0.01 microgram/g.

Animal Feed↗