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Biomedical subjects

M Yamashiro

Publications and source records attributed to M Yamashiro.

At least 19 recordsLinked to original sources
PubMed2006

[Postoperative management for severe pulmonary hypertension in a patient with congenital mitral stenosis and patent ductus arteriosus].

A 1-year and 11-month-old girl with congenital mitral stenosis (MS) and patent ductus arteriosus (PDA) underwent mitral valve replacement (CarboMedics 16 mm) and ligation of PDA. Though she had suffered from severe postoperative pulmonary hypertension crisis, the inhalation of nitric oxygen (NO) with intravenous use of phosphodiesterase (PDE) III inhibitor and prostaglandin I2 (PGI2) was useful for the postoperative management. Severe pulmonary hypertension is the one of critical postoperative complications for congenital MS with PDA cases. Therefore adequate treatments, such as the combination of NO, PDE Ill inhibitor and PGI2, should be important for those cases. In our case, cardiac catetherization revealed a remaining of pulmonary hypertension under medication of beraprost sodium. Further observation should be necessary for the patient including new medicine, such as sildenafil citrate.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2005

Solid serous cystadenoma of the pancreas: MR imaging with pathologic correlation.

We report a case of solid type serous cystadenoma of the pancreas. Computed tomographic and magnetic resonance (MR) images showed a hypervascular solid tumor that was difficult to differentiate from endocrine tumor of the pancreas. However, the tumor showed marked hyperintensity similar to that of hepatic cyst on MR cholangiopancreatography, indicating not a solid but rather a cystic nature. MR cholangiopancreatography (heavily T2-weighted image) is quite useful for clearly differentiating solid from cystic tumors.

Cystadenoma, Serous↗
PubMed2005

[Surgical repair of isolated anomalous origin of left pulmonary artery from the ascending aorta in a 2-month-old infant].

A 2-month-old infant was referred to our department for evaluation of a congestive heart failure. The chest X-ray showed an enlarged globular heart. Further work-up was consistent with an anomalous origin of left pulmonary artery (PA) from the ascending aorta. The patient underwent a corrective surgery using cardiopulmonary bypass. The left PA was arising 15 cm above the aortic annulus and coursed in the curved manner to the left, crossing the main PA where the media of both vessels were fused. The ligamentum arteriosus, running from the top of the main PA to the right aortic arch, was divided. The left PA was detached at its origin and anastomosed to the main PA. The anterior wall of the main PA, where the media was fused, was reinforced with polytetrafluoroethylene (PTFE) patch. An angiogram 6 months after operation showed a rapid antegrade flow to the left PA, and angiographically normal luminal contour.

Anastomosis, Surgical↗
PubMed2001

Long-term clinical impact of occult hepatitis B virus infection in chronic hepatitis B patients.

BACKGROUND/AIMS: Long-term clinical outcomes of occult hepatitis B virus (HBV) infection were studied. METHODS: Fifteen chronic hepatitis B patients were monitored for a median of 4.4 years (range 0.9-15.3) after hepatitis B surface antigen (HBsAg) seroclearance. Serum HBV DNA was measured by real-time detection polymerase chain reaction. Thirteen patients underwent liver biopsies at the end of follow-up and liver histology was evaluated by Ishak score. Liver HBV DNA was also measured for 12 patients. RESULTS: At the end of follow-up, HBV viremia was absent in 13 (87%) patients, and antibody titers to hepatitis B core antigen showed an inverse correlation with time from HBsAg seroclearance (r=-0.554; P=0.0040). However, all patients retained liver HBV DNA and tested positive for the covalently closed circular HBV DNA replicative intermediate. The hepatic HBV DNA loads had no relation to liver histology. Paired biopsies from 11 patients disclosed that each necroinflammatory score significantly improved after HBsAg seroclearance. Amelioration of liver fibrosis was also evident in eight (73%) patients (P=0.0391 by signed rank test). CONCLUSIONS: A long-standing but strongly suppressed HBV infection may confer histological amelioration after HBsAg seroclearance.

Adult↗
PubMed2001

[Clinical features in six patients with liver abscess caused by Streptococcus milleri].

Among 39 patients with pyogenic liver abscess who were admitted to our institute, six (15%) were infected by Streptococcus milleri (S. milleri). We investigated clinical features of these six patients. There were five males and one female, aged 43-81 years old (mean: 61). Five of the six patients had underlying illness. All patients had fever, and three of them complained of abdominal pain. Three patients had mixed infections; particularly intraoral anaerobes, Fusobacterium, were found in two of the three patients. There were no differences in clinical features between patients with S. milleri liver abscess and those with other bacterial liver abscess. In conclusion, on selecting antibiotics for the treatment of liver abscess, it is necessary to consider the S. milleri and intraoral anaerobes.

Adult↗
PubMed2000

Hemodynamics of small hepatic focal nodular hyperplasia: evaluation with single-level dynamic CT during hepatic arteriography.

OBJECTIVE: We examined the usefulness of single-level dynamic CT during hepatic arteriography to observe the hemodynamics of small hepatic focal nodular hyperplasia. CONCLUSION: Single-level dynamic CT during hepatic arteriography revealed not only centrifugal blood supply through the fibrous stellate scar, but also the drainage to dilated veins in or near the focal nodular hyperplasia nodule and directly to the hepatic sinusoid in the surrounding liver.

Adult↗
PubMed2000

Malignant colonic obstruction due to extrinsic tumor: palliative treatment with a self-expanding nitinol stent.

OBJECTIVE: The purpose of this study was to evaluate the usefulness of self-expanding nitinol stents for palliative treatment of malignant colorectal obstruction caused by unresectable extrinsic tumor, colorectal metastasis, or peritoneal seeding. SUBJECTS AND METHODS: One covered stent and 10 uncovered stents were deployed in eight patients with colorectal obstruction due to extrinsic tumor under fluoroscopic guidance. The sites of obstruction were located in the rectum (n = 5), in the rectosigmoid colon (n = 2), and from the transverse colon to the descending colon (n = 1). Clinical usefulness and complications were analyzed. RESULTS: Stents were placed successfully in all patients. Minor modifications of the delivery system were required in the tortuous rectosigmoid and lower rectum strictures. Symptoms of obstruction were initially resolved in all but one patient. In that patient, the presence of other points of obstruction was suspected. Bowel obstruction recurred in two patients: one obstruction was due to migration of a covered stent 4 days after the procedure, and the other obstruction was due to peritoneal seeding 33 days after the procedure. Both required colostomy or ileostomy. All patients died 12-111 days after stent placement (mean, 56 days). In five patients (63%), colonic obstruction was palliated by placing a stent until the patients' death between 39 and 111 days after stent placement (mean, 62 days). Six complications occurred in four patients and included stent migration (n = 1), anal bleeding (n = 2), anal pain that required analgesia (n = 1), and fever (n = 2). CONCLUSION; This self-expandable nitinol stent adequately palliated 63% of patients with colonic obstruction due to extrinsic tumor in this small series. Patient selection is very important to the success of this treatment.

Alloys↗
PubMed1999

Aberrant expression of stem cell factor on biliary epithelial cells and peribiliary infiltration of c-kit-expressing mast cells in hepatolithiasis and primary sclerosing cholangitis: a possible contribution to bile duct fibrosis.

Hepatolithiasis and primary sclerosing cholangitis (PSC) are intractable chronic biliary diseases. In hepatolithiasis, bilirubin-calcium stones are packed in multiple irregularly dilated intrahepatic bile ducts. In PSC, small bilirubin-calcium stones develop terminally. The progressive periductal fibrosis with dilated and stenotic bile ducts in these two diseases may play a role in their incurability. This immunohistochemical study has investigated the expression of some factors that might be involved in fibrogenesis in hepatolithiasis and PSC. Many mast cells positive for c-kit were found in the periductal and ductal fibrosis around the intrahepatic large bile ducts and also around the proliferative peribiliary glands. These mast cells also expressed basic fibroblast growth factor and/or tumour necrosis factor-alpha, which are known as fibrogenetic factors. It was of interest that the aberrant expression of stem cell factor (SCF), a ligand of c-kit, was demonstrated on biliary epithelia of the dilated and stenotic bile ducts showing periductal fibrosis and inflammation and also of the proliferated peribiliary glands in hepatolithiasis and PSC, while no such expression was seen in non-affected bile ducts in hepatolithiasis or in the bile ducts in normal livers. Some of the infiltrating mononuclear cells around the SCF-expressing bile ducts were also positive for SCF. It seems likely that aberrantly expressed SCF on biliary epithelial cells accumulates and stimulates mast cells via the c-kit receptor and that these up-regulated mast cells induce progressive periductal and portal fibrosis by displaying fibrogenetic factors in hepatolithiasis and PSC.

Bile Ducts, Intrahepatic↗
PubMed1999

Ultrasonography in the diagnosis of palatal tumors.

OBJECTIVE: The purpose of this study was to evaluate the usefulness of ultrasonography for the preoperative evaluation of palatal salivary gland tumors. STUDY DESIGN: Eleven surgically treated patients with salivary gland tumors of the palate were examined retrospectively. Intraoral ultrasonic scanning examinations were performed with a 10-MHz transducer. RESULTS: The ultrasonographically well-delimited tumors had a complete capsule histologically, whereas the poorly delimited tumors had no capsule or only an incomplete capsule. The tumors that had a reinforced posterior wall echo were associated with pressure bone absorption, and the tumors that had a reinforced posterior echo were associated with bone destruction. Echograms of the tumors were classified into 4 types on the basis of the internal echoes. CONCLUSIONS: Intraoral ultrasonography of palatal tumors can be used to determine the localization and condition of the tumors by close analysis of the echogram. The internal echo pattern on the ultrasonogram of a palatal tumor was found to reflect the pathologic structure of the tumor. Ultrasonography can therefore be a quite useful technique for the preoperative evaluation of palatal salivary gland tumors.

Adenocarcinoma↗
PubMed1998

Distribution of intrahepatic mast cells in various hepatobiliary disorders. An immunohistochemical study.

There is evidence that mast cells are involved in a number of pathophysiological processes. The significance of mast cells in hepatic fibrosis was examined in 28 patients with histologically normal livers, 34 with acute liver diseases, 51 with chronic liver diseases, and 59 with cholestatic biliary diseases, using immunostaining of the mast cell-specific proteinase, tryptase. Mast cells that were positive for tryptase and for chymase were significantly increased in frequency in fibrotic portal tracts and fibrous septa, particularly in cholestatic/biliary diseases. Mast cells were also increased in frequency around the fibrotic septal and intrahepatic large bile ducts and peribiliary glands of biliary diseases. However, they were less common or even rare in the sclerotic bile ducts and in scarred portal or septal fibrosis. More than half of these more numerous mast cells were positive for histamine, and some were also positive for basic fibroblast growth factor. These two substances were detectable by immunoelectron microscopic in the cytoplasmic granules of mast cells. In contrast, mast cell numbers were not significantly increased in acute viral or drug-induced hepatitis, or in zones 2 and 3 of the hepatic acinus with respect to pericellular and perivenular fibrosis in chronic liver diseases. These findings suggest that mast cells increase in number in cholestatic/biliary diseases, and to a lesser degree in chronic liver diseases, and are involved in the active fibrous enlargement of portal tract and fibrous septa formation and also in the fibrosis of the intrahepatic bile ducts as they display fibrosis-promoting factors such as tryptase, fibroblast growth factor and histamine.

Acute Disease↗
PubMed1998

Dental bur fragments causing metal artifacts on MR images.

PURPOSE: Our purpose was to define the role of dental bur fragments in producing metal artifacts on MR images. METHODS: Dental prosthetic reconstructions were made for two dogs. The two lower second premolars were prepared for full-cast crowns by using a diamond bur. The crown margin was placed subgingivally on the right side (1 mm below the free gingival margin) and at the same level as the free gingival margin on the left side. After 1 week, full-cast crowns were cemented in place. MR imaging was performed 7 days later. RESULTS: Metal artifacts appeared in both second premolar regions of the mandible on MR images, with the right side, in which the crown margin was positioned subgingivally, displaying a larger signal distortion than the left side. After removal of the crown, the artifact remained on the right. On histopathologic examination, bur fragments were detected in the gingiva, more on the right than on the left. X-ray fluorescent element analysis showed iron in the gingival tissue containing bur fragments. CONCLUSION: Distortion of MR images was considered to be attributable in part to the damage of the gingiva and in part to the presence of dental bur fragments.

Animals↗
PubMed1996

[A study on colorimetry of oral mucosal lesions].

Color observation is essential to diagnose oral mucosal lesions. In order to measure and record the color of the oral mucosa more objectively, colorimeters were evaluated. The noncontact-type colorimeter showed considered values comparable with those of visual color matching and was reliable. The color distribution of the normal oral mucosa was from 5.0R to 4.1YR in hue, 3.5 to 6.0 in value, and 3.7 to 6.7 in chroma. The color distribution of leukoplakia was from 2.6RP to 3.4YR in hue, 3.7 to 7.0 in value, and 0.3 to 8.3 in chroma and the ranges thereof were considerably broader than those of normal mucosa and other mucosal lesions. The higher chroma of leukoplakia was, the severer epithelial dysplasia was. The color distribution of oral cancer was from 3.0R to 8.2YR in hue, 2.7 to 6.4 in value, and 3.0 to 7.8 in chroma. The ranges of color distribution was broader than those of normal mucosa and narrower than those of leukoplakia. The color distribution of lichen planus was from 1.7R to 8.9R in hue, 3.5 to 6.3 in value, and 3.6 to 8.5 in chroma. The chroma of erythema is the highest of all mucosal lesions. Some oral mucosal lesions are suggested to have characteristic colors.

Adult↗
PubMed1996

Clinically safe dosage of felypressin for patients with essential hypertension.

Hemodynamic changes were evaluated in patients with essential hypertension when felypressin of various concentrations was administered. The parameters studied were systolic pressure, diastolic pressure, heart rate, left ventricular systolic phase, and endocardial viability ratio. Results showed that blood pressure tended to increase, and the value of 1/pre-ejection period2 (PEP2) tended to decrease, upon administration of 3 ml of 2% propitocaine containing 0.06 international units/ml (IU/ml) of felypressin. Significant increase of blood pressure and decrease in 1/PEP2 was noted upon administration of 3 ml of anesthetic solution containing 0.13 IU/ml of felypressin. No ischemic change of the myocardium was detected even with the highest felypressin concentration (3 ml of 2% propitocaine containing 0.25 IU/ml of felypressin). These results suggest that the clinically safe dosage of felypressin for patients with essential hypertension is approximately 0.18 IU. This amount is equivalent to 6 ml of 3% propitocaine with 0.03 IU/ml of felypressin, which is a commercially available local anesthetic for dental use. It seems that the decrease in 1/PEP2 that occurred during blood pressure increase was due to the increase in afterload caused by contraction of the arterioles. Although in the present study no ischemic change was noted, special care should be taken to prevent myocardial ischemia in patients with severe hypertension.

Analysis of Variance↗
PubMed1995

[A report of leiomyosarcoma of the esophagus].

Leiomyosarcoma of the esophagus is an uncommon disease of which only 97 cases including the present case have been reported in Japan. We report a case of the tumor which showed multiple hematogenous metastases after surgery. A 73-year-old male was admitted complaining of dysphagia and vomiting. Esophagography and endoscopy revealed a large protruding lesion in the lower esophagus. CT scanning revealed threefold-sized extramural mass. Boring biopsies failed to yield evidence of malignancy. However, we performed surgical treatment because of the uncommon size for a benign tumor. The excised tumor was 11 x 9 x 5 cm in size and was diagnosed histologically as leiomyosarcoma of the esophagus without any nodular involvement. Metastatic tumor in the right rib was found 14 months after the operation. Radiotherapy failed to decrease tumor size but eliminated pain. Bone metastases appeared successively and the patient died 3 years and 4 months after operation. Chemotherapy had no effect. Autopsy revealed metastases to the ribs, vertebrae, sternum, pelvic kidneys and diaphragm, but no local recurrence. There is a great need for the development of effective anti-cancer drugs for leiomyosarcomas, particularly in cases with extensive metastasis, such as presented here.

Adult↗
PubMed1995

[Risk factors of operative death and prognosis following operations for esophageal cancer in the elderly].

Risk factors of operative death and prognosis in the elderly following operations for esophageal cancer were evaluated by multivariate analyses. Data were obtained from 45 operations over a 14-year period in patients of a mean age of 72.6 +/- 6.3 years. Using a multiple logistic model analysis, it was determined that the significant risk factor of death within 50 postoperative days was postoperative pulmonary complication. No other factors were significant as risk factors with regard to survival. Cox's proportional hazards model analysis was used to assess the prognostic factors of long-term survival following operations. Independent predictors were the stage of cancer and age. We conclude that two points are essential to improve the survival rate of elderly patients with esophageal cancer; first, postoperative special attention in order to prevent pulmonary complications and secondly, performing operations at as early a stage of cancer as possible.

Aged↗
PubMed1995

Effectiveness of conscious sedation with a single benzodiazepine compared with a combination of drugs.

These results were all obtained by dental anesthesiologists in our clinic actually conducting conscious sedation while observing the patients' response and appearance. Consequently, the anesthesiologist's preferences and skill seem to influence the drugs chosen and the method of use. In reviewing these 300 cases, we found many in which the procedure was completed within 40 min, and effective sedation could be achieved by intravenous sedation using a single benzodiazepine. When a variety of dental treatments are scheduled, tooth extraction is usually performed last. Since the depth of sedation in such cases has become shallow, carelessly performed local anesthetic injections lead to undesirable results. Aside from the nature and duration of treatment, when sedation was employed because of patients' problems, such as anxiety concerning the procedure, good sedation was often achieved with a benzodiazepine, even for relatively lengthy treatments. When a benzodiazepine failed to achieve good sedation on first administration in patients scheduled for repeated sedation, additional drugs are sometimes required from the second time onward. In patients with a gag reflex, conscious sedation with a benzodiazepine alone, and without a comprehensive sedation plan, often ends in failure, and ultimately high doses of multiple drugs have been used in some patients. In some cases, patient management was impossible without general anesthesia.

Anesthesia Recovery Period↗
PubMed1994

[Changes in surgical treatment of peptic ulcer in the elderly by H2-blockers].

It has common knowledge that the advent of H2-blockers has radically changed the treatment of peptic ulcer. We reviewed 26,667 endoscopic examinations, 5,800 consecutive autopsies and 134 consecutive patients operated for peptic ulcer over an 18-year period to evaluate the effects of H2-blockers on the treatment of peptic ulcer in the elderly (> or = 60 years of age). The number of operations for peptic ulcer in the elderly markedly declined after H2-blocker therapy was introduced. This is mainly due to decreased operative indications for gastric bleeding as a result of conservative treatment. However, the incidence of perforating ulcers has hardly changed even after the introduction of H2-blockers. More than 90% of these cases were non-diagnosed or non-treated ulcers and 50% of them were NSAID- or steroid-treated, which is characteristic in the elderly. We conclude that patients to be treated by anti-inflammatory drugs should be screened by endoscopy, and should be given anti-ulcer drugs prophylactically if necessary.

Aged↗