Biomedical subjects

T Masaki

Publications and source records attributed to T Masaki.

593 records · Page 33Linked to original sources

PubMedDate not supplied

Patient-administered nitrous oxide/oxygen inhalation provides effective sedation and analgesia for colonoscopy.

In a double-blind, randomized, placebo-controlled study of patients undergoing colonoscopy, sedation with an inhaled mixture of nitrous oxide/oxygen was compared with conventional intravenous sedation (pethidine 50 mg, midazolam 2.5 mg). In the patients studied, no significant differences were noted in number of pain episodes, need for additional intravenous sedation, or patient pain scores between the group receiving the nitrous oxide/oxygen mixture (n = 30) and those managed with conventional benzodiazepine/opiate injection (n = 29). Both methods were significantly more effective than placebo (n = 30). Six patients in the benzodiazepine/opiate group had oxygen desaturation, whereas none did in the nitrous oxide/oxygen group. Duration of stay after the procedure was significantly shorter in the gas inhalation group than in those receiving conventional intravenous sedation. Except for patients with severe chronic obstructive pulmonary disease, nitrous oxide/oxygen inhalation is a safe and acceptable alternative method of sedation and analgesia during colonoscopy.

Adolescent↗

PubMedDate not supplied

Cloning of a cDNA encoding a non-isopeptide-selective subtype of the endothelin receptor.

Endothelin-1 was initially identified as a 21-residue potent vasoconstrictor peptide produced by vascular endothelial cells, but was subsequently found to have many effects on both vascular and non-vascular tissues. The discovery of three isopeptides of the endothelin family, ET-1, ET-2 and ET-3, each possessing a diverse set of pharmacological activities of different potency, suggested the existence of several different endothelin receptor subtypes. Endothelins may elicit biological responses by various signal-transduction mechanisms, including the G protein-coupled activation of phospholipase C and the activation of voltage-dependent Ca2+ channels. Thus, different subtypes of the endothelin receptor may use different signal-transduction mechanisms. Here we report the cloning of a complementary DNA encoding one subtype belonging to the superfamily of G protein-coupled receptors. COS-7 cells transfected with the cDNA express specific and high-affinity binding sites for endothelins, responding to binding by the production of inositol phosphates and a transient increase in the concentration of intracellular free Ca2+. The three endothelin isopeptides are roughly equipotent in displacing 125I-labelled ET-1 binding and causing Ca2+ mobilization. A messenger RNA corresponding to the cDNA is detected in many rat tissues including the brain, kidney and lung but not in vascular smooth muscle cells. These results indicate that this cDNA encodes a 'nonselective' subtype of the receptor which is different from the vascular smooth muscle receptor.

Amino Acid Sequence↗

PubMedDate not supplied

Renal expression of mRNAs for endothelin-1, endothelin-3 and endothelin receptors in NZB/W F1 mice.

Endothelin (ET)-1, ET-3, and ET receptors are widely distributed in the vascular system and the kidney. The present study was designed to measure the renal concentrations of ET-1, ET-3, and ET receptor mRNAs in NZB/W F1 mice at 8, 24, and 48 weeks of age. The renal concentration of ET-1 mRNA increased significantly in NZB/W F1 mice as their nephritis progressed, reaching, by 48 weeks, a 10-fold higher concentration than in control NZW mice. Renal ET-3 mRNA concentrations, however, remained unchanged. The renal concentrations of ET receptor A and B mRNAs in NZB/W F1 mice increased gradually with the progression of nephritis, reaching 5- and 3-fold higher concentrations, respectively, at 48 weeks of age than found in control mice. Transforming growth factor-beta (TGF-beta) and tumor necrosis factor-alpha (TNF-alpha) have been shown to stimulate ET-1 mRNA expression in cultured mesangial cells. We therefore also examined the concentrations of TGF-beta and TNF-alpha mRNAs in the renal tissues of NZB/W F1 mice, and found that, at 48 weeks of age, they were 10- and 8-fold higher, respectively, than in control NZW mice. At 24 weeks, NZB/W F1 mice were divided into two groups receiving either methylprednisolone (MPSL) or saline injections for the following 24 weeks. The development of the histologic lesions characteristic of lupus nephritis and the increased renal concentrations of ET-1, ET receptors, TGF-beta and TNF-alpha mRNAs were suppressed by MPSL treatment. These data suggest that ET and ET receptor gene transcription is upregulated in the renal tissues of NZB/W F1 mice and that the beneficial treatment of lupus nephritis with MPSL is accompanied by a reduction in the elevated concentrations of ET-1, ET receptors, TGF-beta and TNF-alpha mRNAs.

Aging↗

PubMedDate not supplied

Role of transforming growth factor-beta 1 in glomerulonephritis.

The role of transforming growth factor-beta 1 (TGF-beta 1) in human glomerulonephritis is still poorly understood. The relationship between expression of TGF-beta 1 protein or TGF-beta 1 mRNA and tissue damage was investigated using the enzyme-antibody and in situ hybridization method in frozen slices of renal tissue from 30 patients: 25 with glomerulonephritis (18 with immunoglobulin A nephropathy; two with focal glomerulosclerosis, one with membranous nephropathy, one with crescentic glomerulonephritis and three with lupus nephritis) and five control patients with minimal change disease. The expression of TGF-beta 1 mRNA was high in sclerotic and proliferative glomeruli, as well as in the tubular epithelial cells within tubulointerstitial lesions. There was significant correlation between the severity of tissue damage in immunoglobulin A nephropathy and the presence of TGF-beta 1 protein and TGF-beta 1 mRNA. These findings suggest that TGF-beta 1 is involved in glomerulosclerosis and the development of tubulointerstitial lesions, indicating its potential importance in the progression and aggravation of immunoglobulin A nephropathy.

Adolescent↗

PubMedDate not supplied

Role of tenascin in human immunoglobulin A nephropathy.

Tenascin is a component of the extracellular matrix that responds rapidly to inflammation or injury. The activity index and chronicity index of immunoglobulin A nephropathy are mainly used to decide whether or not steroid therapy is indicated, but are sometimes difficult to evaluate histologically. We investigated whether tenascin staining of the glomeruli was an indicator of the activity or chronicity indices in patients with immunoglobulin A nephropathy. Tenascin staining was evaluated immunohistochemically in 38 renal specimens, including 32 from patients with immunoglobulin A nephropathy and six from control kidneys, and the extent of staining was scored. Tenascin staining was correlated with the chronicity index (r = 0.643, P < 0.0003) but not with the activity index.

Adolescent↗

PubMedDate not supplied

Dose-dependent effect of an oral adsorbent, AST-120, in patients with early chronic renal failure.

We evaluated the dose dependence of an oral adsorbent, AST-120, in 31 patients with early chronic renal failure (baseline serum creatinine: 1.2-3.0 mg/dl). Twenty-three patients were given AST-120 and eight patients were not. AST-120 was administered at three different maintenance doses, < 3.0 g, 3.0 g and 6.0 g/day, according to patients' ability to tolerate treatment. The treatment period was 12 months. The slope of the reciprocal of serum-creatinine concentration versus time was calculated to assess the progression of renal failure. This slope became significantly less steep after AST-120 treatment at 6.0 g/day, but did not change significantly at the other doses. These findings suggest that 6.0 g/day of AST-120 may delay the initiation of dialysis in patients with early chronic renal failure.

Administration, Oral↗

PubMedDate not supplied

High molecular weight-neutrophil chemotactic activity in nasal allergy.

HMW-NCA is involved in the pathogenesis of nasal hypersensitivity reactions in humans. We, however, have little evidence about the role of neutrophils which migrate to the site of allergic reactions by HMW-NCA and other chemotactic mediators. This role of neutrophils in nasal hypersensitivity still remains to be clarified.

Chemotaxis, Leukocyte↗

PubMedDate not supplied

Drug effects on antigen-induced release of high molecular weight-neutrophil chemotactic activity and histamine in nasal secretion from children with allergic rhinitis.

Five children with allergic rhinitis sensitive to house dust mite as documented by skin test, radioallergosorbent test, score and nasal provocation were studied. Patients were subjected to nasal challenge with 3.125, 6.25, 12.5, and 25 protein nitrogen micrograms per disc of house dust mite antigens and nasal secretions were collected by the filter paper method. Neutrophil chemotactic activity (NCA) and histamine content of the nasal secretions were measured. NCA and histamine were released in a dose- and time-dependent manner, and no significant correlation between NCA and histamine was revealed in each subject. Pretreatment with 5.2 mg of nasal disodium cromoglycate or 0.5 micrograms of nasal adrenaline 5 minutes before provocation totally inhibited mediator release upon nasal challenge with 12.5 micrograms of house dust mite. A dose of 100 micrograms of nasal beclomethasone dipropionate 5 minutes before challenge neither inhibited clinical symptoms nor mediator release; 100 micrograms x 3 times per day of nasal beclomethasone dipropionate for 3 days, however, significantly inhibited clinical symptoms and release of both NCA (p less than 0.05) and histamine (p less than 0.05). NCA eluted as a single peak with an estimated molecular weight of 600,000. These results suggest that high molecular weight-NCA may be involved in the pathogenesis of allergic rhinitis.

Allergens↗

PubMedDate not supplied

Transmesenteric hernia after laparoscopic-assisted sigmoid colectomy.

BACKGROUND AND OBJECTIVES: Laparoscopic-assisted surgery has been applied for a variety of colonic surgery. The objective of this paper is to demonstrate a possible and avoidable complication of laparoscopic colonic surgery. CASE PRESENTATION: A 47-year-old woman underwent gasless laparoscopic-assisted sigmoid colectomy. On the 20th postoperative day, she developed bowel obstruction. Decompression with a long tube failed to resolve the bowel obstruction. Open laparotomy was performed. Abdominal exploration revealed a loop of the small bowel incarcerated in the mesenteric defect caused by the previous operation. Adhesiolysis was performed, and the postoperative course was uneventful. DISCUSSION: Despite technical difficulty, complete closure of the mesentery after bowel resection is strongly recommended for prevention of transmesenteric incarcerated hernia after laparoscopic surgery.

Adenocarcinoma↗

PubMedDate not supplied

Non-polypoid colorectal neoplasias: a multicentric study.

A total of 781 non-polypoid colorectal neoplasias harvested at 4 main Hospitals in Tokyo, Japan (n = 420) and at 4 different time-intervals at the Karolinska Hospital, Stockholm, Sweden (n = 361) were reviewed. By applying strict histologic definitions, the lesions were classified into adenomas with low grade dysplasia (LGD), with high grade dysplasia (HGD), intramucosal carcinomas (IMC) or submucosal carcinomas (SMC). Of the non-polypoid neoplastic lesions reviewed in Sweden, 82.8% (n = 299) had LGD. In Japanese patients only 42.6% (n = 179) had LGD (p < or = 0.001). On the other hand, as many as 42.4% (n = 178) of the non-polypoid lesions in Japanese patients had HGD, but only 14.1% (n = 51) of those in Swedish patients (p < or = 0.001). Whereas 15.0% (n = 63) of the non-polypoid neoplasias seen in Japan were IMC or SMC, only 3.0% (n = 11) of those seen in Sweden were IMC or SMC (p < or = 0.001). The cause(s) for these differences remains unclear. In Japan, however, a marked increased incidence of colonic cancer has been recorded in later years. Whether the "catching up phenomenon" by the Japanese with western colonic cancer incidence includes increased histologic aggressiveness of non-polypoid neoplastic polyps--as found in this survey--remains to be elucidated.

Adenoma↗

PubMedDate not supplied

Primary intestinal obstruction complicated by persistent descending mesocolon.

Persistent descending mesocolon is an uncommon developmental anomaly which results from failure of fusion of the descending mesocolon with the posterior parietal peritoneum. It is asymptomatic in most cases and rarely causes intestinal obstruction. We report here a case of primary intestinal obstruction complicated by a persistent descending mesocolon. A 66-year-old man without prior laparotomy was admitted with a diagnosis of small bowel obstruction. Pre-operative investigation demonstrated a segmental jejunal stenosis and a persistent descending mesocolon as possible causes of the obstruction. Laparotomy showed that the cause of the obstruction was the jejunal stenosis, not the persistent descending mesocolon. The stenosis was resected, but correction of the anomaly was not performed. The patient made an uneventful recovery after the operation. From our limited experience, persistent descending mesocolon need not be surgically corrected when it is not considered to be the cause of obstruction and another definite cause co-exists.

Aged↗

PubMedDate not supplied

Quantitative analysis of telomerase activity: a potential diagnostic tool for colorectal carcinoma.

BACKGROUND/AIMS: We describe the results of the application of the nonradioactive F-TRAP (fluorescence-based telomeric repeat amplification protocol) assay for the diagnosis of colorectal carcinoma(s). We also investigated whether the level of telomerase activity in colorectal carcinoma can be distinguished from that in normal colorectal tissue or benign colorectal tumors, in which the presence of telomerase activity has also been demonstrated. In addition, we also investigated whether it could be a potential tumor progression marker. METHODOLOGY: The F-TRAP assay was performed, using biopsy specimens obtained from colonoscopic examinations, including 20 colorectal carcinoma, 10 tubular adenoma and 20 adjacent colorectal normal tissue specimens. In 15 carcinoma cases, the correlation between telomerase activity level and clinicopathological parameters was analyzed. RESULTS: The results showed that the level of telomerase activity in colorectal carcinomas (88.71 +/- 92.1 units; mean +/- SD) was much higher than that in normal colorectal tissues (3.34 +/- 8.57 units) or adenomas (7.8 +/- 10.27 units). By quantifying the level of telomerase activity using the F-TRAP assay, colorectal carcinomas can be distinguished from normal colorectal tissue or colorectal benign tumors. However, no significant correlation was observed between telomerase activity levels and clinicopathological parameters such as depth of tumor invasion, lymphatic and/or venous involvement, and regional lymph node metastasis and Dukes' stage. CONCLUSIONS: Quantitative analysis of the level of telomerase activity using the F-TRAP assay provides a useful diagnostic tool for colorectal carcinoma, but it would not be useful as a tumor progression marker.

Adenoma↗

PubMedDate not supplied

Endoscopic biliary stenting for treatment of bile leakage after hepatic resection.

BACKGROUND/AIMS: Persistent bile leakage after hepatic resection may cause intraperitoneal sepsis and hepatic failure. Surgical treatment for bile leakage carries a high risk. Endoscopic treatment has only infrequently been documented. METHODOLOGY: Ten patients underwent endoscopic biliary stenting without sphincterotomy for persistent (9-138 days; median, 19 days) bile leakage after hepatic resection. Bile leakage was complicated by intraperitoneal sepsis in seven patients. RESULTS: ERCP showed bile leakage from the bile duct stump in nine patients. Stent placement was successful without complications in all 10 patients. Bile leakage disappeared within 1-17 days (mean, 5 days) in all patients. After 55-91 days, the stent was removed and ERCP confirmed disappearance of the leak. No patients have developed recurrent bile leakage for a mean of 4.1 years of follow-up after stent removal. CONCLUSIONS: Endoscopic biliary stenting is a safe and effective treatment for persistent bile leakage after hepatic resection. Endoscopic treatment may eliminate the need for difficult operations in high risk postoperative cases.

Adult↗

PubMedDate not supplied

Preoperative endoscopic pancreatic stenting for safe local pancreatic resection.

Local pancreatic resection and enucleation have the advantage of preserving pancreatic parenchyma but pancreatic fistula often occurs postoperatively. We describe a case in which preoperative endoscopic pancreatic stenting prevented pancreatic fistula formation following local pancreatic resection. A pancreatic stent seems to prevent leakage from small pancreatic branch ducts not identified or ligated intraoperatively, via the pancreatic decompression effect. The present case demonstrates a novel indication for endoscopic pancreatic stenting.

Carcinoma, Pancreatic Ductal↗

PubMedDate not supplied

Pancreatic carcinoma associated with anomalous pancreaticobiliary junction.

Anomalous pancreaticobiliary junction often leads to biliary tract carcinoma but only rarely to pancreatic carcinoma. We report three cases of pancreatic carcinoma associated with anomalous pancreaticobiliary junction. All three were female with a mean age of 68 years. Carcinomas were located in the pancreatic head (n = 2) or body (n = 1). None had choledochal cyst and one had experienced recurrent acute pancreatitis. All carcinomas were at an advanced stage with a poor prognosis. No unique imaging or histologic findings of the carcinomas could be identified. Attention should be paid to the possibility of pancreatic carcinoma in patients with anomalous pancreaticobiliary junction, particularly in aged patients. Early diagnosis and treatment of anomalous pancreaticobiliary junction may prevent development of pancreatic carcinoma.

Adolescent↗

PubMedDate not supplied

Effects of capsaicin on the contractility and peptide-containing nerves of large cerebral arteries of the cat.

Capsaicin caused a vasoconstrictor response of the cat middle cerebral and basilar arteries in vitro both in the presence and absence of active tone. The vasoconstrictor response to capsaicin appeared and attained almost the maximum level at a dose of 10(-7) M. It is likely that capsaicin directly induced a contraction of smooth muscle cells, since the vasoconstrictor response was independent of the presence of endothelium and nerve components. When the tissue exhibited an active tone by the application of uridin 5'-triphosphate, the contractile response was evoked by capsaicin at lower concentrations. The maximum developed tension was greater in denervated tissues than in control tissues. After the exposure of the tissue to capsaicin in vitro, the intensity of substance P- and CGRP-like immunofluorescence diminished markedly, while that of neuropeptide Y- and vasoactive intestinal polypeptide-like immunofluorescence was not grossly altered. These results indicate that, while capsaicin releases and depletes some vasodilator peptides from perivascular nerves, the powerful direct vasoconstrictor effect overwhelms the vasodilator effects in large cerebral arteries of cats.

Animals↗

PubMedDate not supplied

Histologic differences between flat tubular colorectal neoplasias in Japan and Sweden.

A total of 231 flat colorectal neoplasias were investigated at two disparate geographical regions (Stockholm and Tokyo). Of the 141 flat neoplasias seen in Tokyo, 24.8% had HGD, 7.0% intramucosal carcinoma and 9.9% invasive carcinoma. On the other hand, of the 90 flat mucosal neoplasias seen in Stockholm, 13.3% had HGD, 1.1% intramucosal carcinoma and 1.1% invasive carcinoma. The differences between flat adenomas with HGD, intramucosal carcinomas and invasive carcinomas in Japanese patients were significantly higher (p < 0.001) than in Swedish patients. While the causes responsible for this geographic difference remains unclear, possible influences of ethnicity and/or of environmental factors were advanced.

Adenoma↗