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Biomedical subjects

Y Son

Publications and source records attributed to Y Son.

16 recordsLinked to original sources
PubMed2001

Protective effects of morphine in peroxynitrite-induced apoptosis of primary rat neonatal astrocytes: potential involvement of G protein and phosphatidylinositol 3-kinase (PI3 kinase).

Opiates, such as morphine, have been used extensively in the clinical management of pain due to their potent analgesic effect. Astrocytes, representing a major non-neuronal cell population in the CNS, contain opioid receptors that are actively involved in several brain functions. This study was designed to evaluate the effects by which morphine, a preferential mu-opioid receptor agonist, contributes to cytotoxicity of nitric oxide (NO) species, including NO and peroxynitrite (ONOO-), in primary rat neonatal astrocytes. Primary astrocytes isolated from the cerebral cortex of 1- to 2-day-old Sprague-Dawley rats were treated with morphine, naloxone, and 3-morpholinosydnonimine (SIN-1), a donor of peroxynitrite. Morphine significantly protected primary rat astrocytes from apoptosis mediated by sodium nitroprusside, an NO donor, and SIN-1 in a dose-dependent manner, whereas it did not in other types of cells including C6 glioma, RAW 264.7, and HL-60 cells. Moreover, naloxone antagonized the protective effects of morphine on SIN-1-induced apoptosis. Morphine also inhibited the nuclear condensation and fragmentation of SIN-1-treated cells that was antagonized by naloxone pretreatment. The protective role of morphine in SIN-1-induced apoptosis was dependent on an intracellular antioxidant system such as GSH. Furthermore, the effects of morphine on SIN-1-induced cytotoxicity were prohibited by pretreatment with the G(i) protein inhibitor, pertussis toxin, and the phosphatidylinositol 3-kinase (PI3 kinase) inhibitors, wortmannin and LY294002. Taken together, these results suggest that morphine may protect primary rat astrocytes from apoptosis by NO species via the signaling cascades that involve both G protein and PI3 kinase.

Animals↗
PubMed2001

Pharmacological effects of naltriben as a ligand for opioid mu and kappa receptors in rat cerebral cortex.

Naltriben (NTB) has been used to differentiate the subtypes of delta opioid receptors, delta1 and delta2. However, there is considerable evidence suggesting that NTB may act on other types of opioid receptors too. We examined the effects of NTB on the specific binding of radiolabeled ligands for opioid mu and kappa2 receptors, and the effects on the release of [3H]norepinephrine ([3H]NE) in rat cerebral cortex slices. NTB displaced the specific binding of [3H]DAMGO with Ki value of 19.79 +/- 1.12 nM in rat cortex membranes. Specific binding of [3H]diprenorphine ([3H]DIP) was inhibited by NTB with Ki value of 82.75 +/- 6.32 nM in the presence of DAMGO and DPDPE. High K+ (15 mM)-stimulated release of [3H]NE was attenuated by DAMGO in rat cerebral cortex slices. NTB (30 nM) shifted the dose-response curve of DAMGO to the right and attenuated the maximal effect. In the meantime, NTB inhibited high K+-stimulated [3H]NE release at concentrations above 100 nM. The inhibitory effect of NTB was not attenuated by CTAP (10 nM) and naloxone (3 nM) but by higher concentration of naloxone (30 nM), nor-BNI (300 nM) and bremazocine (3 nM). These results indicate that NTB, depending on the dosage, could acts not only as an antagonist at delta but also as a noncompetitive antagonist for mu receptors, and as an agonist for kappa2 receptors in rat cerebral cortex.

Animals↗
PubMed2001

Line quadrisection errors in normal subjects.

Many studies have investigated line bisection behaviors in normal individuals and patients with hemispatial neglect. However, little is known about what happens when subjects attempt to fractionate line into more than two equal components (e.g., line quadrisection). Thirty right handed normal subjects were asked to place a mark either 25% (left quadrisection) or 75% (right quadrisection) of the distance along on a 240 mm line. On average, they placed the left quadrisection mark significantly to the left (- 4.2+/-6.7 mm) from the true quadrisection point but they were relatively accurate on the right quadrisection task (1.0+/-6.7 mm). However, comparison of actual quadrisection performances with those of expected performance based on subjective midpoint disclosed that both right and left quadrisection marks deviate toward each end of the line. Individual data analysis also support this trend because majority of subjects showed the lateral deviation in either or both quadrisection tasks. Therefore, in the left quadrisection task the pseudoneglect (leftward bias) in bisection and the lateral bias are additive, resulting in a robust left lateral deviation, whereas in the right quadrisection, these two biases nullify each other, resulting in accurate performance.

Adolescent↗
PubMed2001

Allometry and biomass of Korean pine (Pinus koraiensis) in central Korea.

Aboveground tree biomass of Korean pine (Pinus koraiensis Sieb. et Zucc.) was determined for a natural forest of Korean pine and mixed deciduous trees and seven age classes of plantation forests in central Korea. Regression analyses of the dry weights of stem wood, stem bark, branches, and needles versus diameter at breast height were used to calculate regression equations of the form of log Y = a + b log X. Biomass of Korean pine in the mixed forest was 118 Mg ha(-1), and biomass in the plantations was linearly related to stand age, ranging from 52.3 Mg ha(-1) in 11 to 20-year-old stands to 317.9 Mg ha(-1) in 71 to 80-year-old stands. The proportions of stem wood and stem bark in the total aboveground biomass decreased with stand age while those of branch and needle increased. Specific leaf area of Korean pine ranging from 35.2 to 52.1 cm2 g(-1) was significantly different among crown positions and needle ages; in general, lower crown position and current needles had the greatest surface area per unit dry weight.

Biomass↗
PubMed2001

Case of adrenocorticotropic hormone-independent macronodular adrenal hyperplasia with possible adrenal hypersensitivity to angiotensin II.

With increasing case reports, it has been indicated that some cases with adrenocorticotropic hormone (ACTH)-independent macronodular adrenal hyperplasia (AIMAH) show abnormal responses in cortisol to various stimulation tests. Here we report a case of AIMAH that showed an aberrant response to angiotensin II via AT1 receptor in cortisol hypersecretion. A 53-yr-old man was admitted to our division seeking further examinations for the possible diagnosis of Cushing's syndrome. He had hypertension, diabetes mellitus, and physical stigmata, such as moon face and central obesity. His plasma ACTH level was undetectable, and plasma cortisol level was high. Plasma cortisol showed no normal diurnal rhythm and was not suppressed after the administration of 8 mg of dexamethasone. Abdominal computed tomography demonstrated nodular enlargement of bilateral adrenal glands. He was diagnosed with Cushing's syndrome owing to AIMAH. An injection of arginine vasopressin (AVP) increased plasma cortisol and aldosterone levels, whereas ACTH remained undetectable. After 4 h in an upright position, plasma cortisol and aldosterone levels were increased. Pretreatment with candesartan, angiotensin II receptor AT1 antagonist, blocked the increase in plasma cortisol level. These results suggested a possibility of adrenal hypersensitivity to angiotensin II and AVP in cortisol secretion. Bilateral laparoscopic adrenalectomy was performed. The histological findings of the specimen were compatible with AIMAH. In summary, we have made the first report on a case of AIMAH with possible hypersensitivity to angiotensin II.

Adrenal Glands↗
PubMed1999

Comparison of incidence of gastroesophageal reflux and regurgitation associated with timing of removal of the laryngeal mask airway: on appearance of signs of rejection versus after recovery of consciousness.

STUDY OBJECTIVES: To compare the incidence of gastroesophageal reflux and regurgitation associated with laryngeal mask airway (LMA) removal when signs of rejecting the LMA, such as swallowing, struggling, and restlessness, were observed and when the patient could open his or her mouth on command. DESIGN: Randomized clinical trial. SETTING: Operating room and recovery room of a tertiary care referral hospital. PATIENTS: 63 ASA physical status I and II adult patients scheduled for elective orthopedic surgery. INTERVENTIONS: Using a standardized general anesthetic technique, patients were allocated randomly to Group A (n = 34; LMA removed when signs of rejection, such as swallowing, struggling, and restlessness, were observed) or Group B (n = 29; LMA removed when the patient could open his or her mouth on command). MEASUREMENTS AND MAIN RESULTS: To detect gastroesophageal reflux throughout anesthesia, a pH monitoring probe was positioned in the lower esophagus on the day before surgery. To assess regurgitation during emergence, a gelatin capsule of methylene blue (50 mg) was swallowed prior to induction. At the end of anesthesia, episodes of reflux and regurgitation of gastric contents were analyzed/determined by pH below 4 and bluish staining of the pharynx and/or LMA, respectively. Physical events such as bucking, straining, and coughing during the arousal phase were recorded in both groups by an independent observer. The incidence of reflux (pH < 4) from the time of the appearance of rejection signs to LMA removal and the total incidence of reflux in Group B were significantly higher than in Group A (p < 0.05). Staining of the LMA and the pharynx by methylene blue was not observed in patients from either experimental group. The number of physical events in Group B during the arousal phase was significantly increased compared to Group A (p < 0.05). Considering all patients in Group A and Group B, physical events were associated with the occurrence of reflux (p < 0.05). Desaturation (SpO2 < 95%) and clinical evidence of aspiration of gastric contents did not occur in either group. CONCLUSION: Maintenance of the LMA until the patient can open his or her mouth on command increases the incidence of gastroesophageal reflux.

Adolescent↗
PubMed1995

Laryngopharyngoesophagectomy for advanced hypopharyngeal and esophageal squamous cell carcinoma: the Yale experience.

The 5-year survival rate for patients with hypopharyngeal squamous cell carcinoma invading the upper esophagus is below 25% regardless of therapy. Most patients with advanced disease--unable to eat or breathe--die within 18 months of diagnosis. Because these patients, on average, have a limited time to live, surgical treatment should aim to maximize the quality of remaining life. Essential to this goal are complete tumor removal and rapid return to oral feeding. Furthermore, short hospital stay and low perioperative morbidity are especially important in these patients. We performed total laryngopharyngoesophagectomy (LPE) with gastric transposition in 34 patients with hypopharyngeal and cervical esophageal squamous cell carcinoma. There has been one perioperative death (3%) and 1 temporary fistula (3%). No major mediastinal or intrathoracic complication occurred. On average, patients began oral feeding by postoperative day 10, with return to a full diet and discharge home within 16 days, maximizing both quality and quantity of time remaining outside the hospital.

Adult↗
PubMed1994

DNA damage in the kidneys of diabetic rats exhibiting microalbuminuria.

8-Hydroxydeoxyguanosine (8-OHdG), an oxygen radical induced modification of purine residue in DNA, was measured in the liver, pancreas, and kidney of streptozotocin-induced diabetic rats (STZR) exhibiting microalbuminuria. At 4 weeks after the injection of streptozotocin (50 mg/kg, i.v.), the rate of urinary albumin excretion was 0.5 +/- 0.1 and 2.0 +/- 0.2 mg/24 h in age-matched control rats (CR) and STZR, respectively. Compared to CR, STZR also showed a significantly increased level of 8-OHdG in the kidney but not the liver and pancreas. Amounts of 8-OHdG/10(5) dG for CR and STZR were 3.4 +/- 0.3 and 5.1 +/- 0.2 for renal cortices, and 4.1 +/- 0.2 and 20.0 +/- 3.7 for renal papillae. Daily injection of insulin (2 U, SC) starting on the third day after streptozotocin treatment significantly reduced both urinary albumin excretion and papillary 8-OHdG formation, which suggests that these are associated with the diabetic state induced by streptozotocin rather than a direct nephrotoxic effect of the drug. This study suggests that formation of 8-OHdG and, therefore, oxidative damage are closely related in the process of diabetic nephropathy.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1994

Effect of non-tumor cell contamination on detection of p53 gene mutations in human gastric cancer cells by polymerase chain reaction single-strand conformation polymorphism analysis.

BACKGROUND: We have previously studied p53 gene mutations in 25 primary gastric cancer tissues by polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) analysis for exon 4-8 and immunohistochemical staining with anti-p53 antibody. In four cases, the discrepancy of the results was observed between the two methods. In one case positive by PCR-SSCP but negative by immunohistochemical staining, the mutation was silent. In three cases, the p53 gene mutations were detected only by immunohistochemical staining. This discrepancy may be due to the contamination of the samples by cells without p53 gene mutation, such as non-tumor cells. This study was conducted to investigate the sensitivity of PCR-SSCP analysis to p53 gene mutations when the sample was contaminated with non-tumor cells. METHODS: Genomic DNA was extracted by the digestion with proteinase K and phenol-chloroform-ethanol method from two human gastric adenocarcinoma cell lines, MKN-45 and KATO III. To investigate the sensitivity of PCR-SSCP, DNA extracted from cancer cells was mixed with DNA obtained from normal gastric mucosal cells at various ratios. PCR-SSCP analysis for exon 4-8 of the p53 gene was performed with the mixed DNA samples. RESULTS: In KATO III, no PCR products were generated in exon 4-8 of the p53 gene by PCR, suggesting that both alleles from exon 4-8 of the p53 gene were deleted. In MKN-45, the mobility shift was observed in exon 4. Therefore, the effect of non-tumor cell contamination on the detection of p53 gene mutations was conducted using MKN-45 and normal gastric mucosal cells. In the mixed DNA samples of MKN-45 and normal gastric mucosal cells, an extra band with the migration similar to that of MKN-45 was found in the samples of 1:8 dilution or less, while no extra band was grossly detectable in DNA of normal gastric mucosal cells and in the samples of more than 1:16 dilution. CONCLUSIONS: These results suggest that the detection of p53 mutations by PCR-SSCP analysis may be underestimated in samples contaminated by a large number of non-tumor cells.

Base Sequence↗
PubMed1989

External irradiation plus curietherapy boost in 108 base of tongue carcinomas.

From 1960 to 1983, 108 patients underwent an association cobaltherapy plus curietherapy boost for a base of tongue carcinoma. This group included 18 T1 tumors, 39 T2, and 51 T3. Cobaltherapy was delivered to a dose of 45 Gy/4.5 weeks to the primary site and the neck. It was completed by an electron boost or a nodal surgery in case of initial nodal disease. Two techniques of Curietherapy were used: plastic tubes and guide-gutters. As most of these implants have been done before 1975, all the doses have been recalculated on the 85% isodose according to the Paris system. They varied from 22 to 88 Gy. The tolerance of the implantation was excellent. Five-year survival of the whole group is 26%. The local control rate is 85% for T1 tumors, 50% for T2, and 69% for T3. Despite the importance of cumulated doses, a few necrosis were observed. Considering the poor outlook of this cancer, its treatment by exclusive radiotherapy requires very high doses which can only be delivered without major sequellae or complication by a combination of cobaltherapy and curietherapy boost.

Adult↗
PubMed1987

Improved local control of thoracic disease in small cell lung cancer with higher dose thoracic irradiation and cyclic chemotherapy.

Over the past decade, improvement in survival has developed for patients with small cell lung carcinoma (SCLC) due to treatment strategies that include: cyclic combination chemotherapy, thoracic irradiation, and prophylactic cranial irradiation. In this study, we assess the outcome of treatment with initial cyclic combination chemotherapy including: cyclophosphamide, VP 16-123 and methotrexate combined with radiotherapy (RT), 6000 cGY [corrected] to the thorax for patients with limited disease and 3000 cGy [corrected] for patients with extensive disease. Forty-six patients are evaluated: 26 patients with limited disease and 20 with extensive disease. In patients who received 6000 cGy [corrected], to thoracic lesions, in combination with chemotherapy, administered for 3 courses prior to and following RT, the rate of clinically detected failure in the thorax was 3.8%. Morbidity was considered acceptable, although the occurrence of encephalopathy in 6 of 19 cases who received cranial irradiation, 3000 cGy [corrected], and concomitant chemotherapy was a serious consequence. Control of the primary tumor achieved by the use of higher dose RT is shown to be superior to that observed at lower doses of RT. This suggests that for the small cohort of patients whose disease is truly limited at the time of diagnosis, therapeutic regimens, which include higher dose RT, could increase the number of long term survivors of SCLC.

Aged↗
PubMedDate not supplied

Developmental changes of calcium-stimulated adenosine triphosphatase in rat submandibular gland.

Developmental changes in Ca2-+ ATPase activity were determined in submandibular glands of the rat from the fetus to the 300-day-old rat. Ca2+-ATPase in the homogenate fraction showed a rapid increase from the fetus to the 5-day-old rat, and from the 20- to 30-day-old rat. In the microsomal fraction, enzyme activity increased from the fetus to the 10-day-old rat, and after that is remained at almost the same level. Oscillatory phenomena of Ca2+-ATPase were observed in zymogen and mitochondrial fractions.

Adenosine Triphosphatases↗
PubMedDate not supplied

Elevation of serum type IV collagen in liver cancer as well as liver cirrhosis.

Studies on the level of serum type IV collagen (IV C) have usually been focused on the disease with diffuse hepatic fibrosis. To investigate whether serum level of IV C was predictive for the development of liver cancer as well as liver cirrhosis, serum IV C level was measured by a one-step sandwich enzyme immunoassay. The mean level of serum IV C was 73.3 +/- 31.3 ng/ml in 48 controls. The levels (ng/ml) of IV C were 396.4 +/- 254.9, 429.6 +/- 320.7, 420.6 +/- 322.8, and 362.9 +/- 247.4 respectively in 11 patients with chronic hepatitis, 11 with liver cirrhosis, 16 with hepatocellular carcinoma (HCC) with cirrhosis, 10 with HCC without cirrhosis, and 10 with metasatic liver cancer, which were significantly higher than that in controls (p < 0.05). Serum IV C levels were also evaluated using a cut-off value which was determined as the mean plus two standard deviations in the controls, 136 ng/ml. The elevations above the cut-off value were observed in 91, 100, 80, and 90% respectively of 11 patients with cirrhosis, 16 with HCC with cirrhosis, 10 with HCC without cirrhosis, and 10 with metastatic liver cancer, while only one (9%) of 11 chronic hepatitis patients and none (0%) of 48 controls had elevated levels. The levels of serum IV C were analysed with regard to age, sex, serum levels of albumin, globulin, transaminases, alpha-fetoprotein, and diameter of liver mass, a significant difference being observed only between the diameter of HCC and serum level of IV C (p < 0.01). These results indicate that the measurement of serum IV C is a useful for the determination of primary and metastatic liver cancer as well as liver cirrhosis.

Adult↗