A case of normotensive pheochromocytoma masquerading as a dilated cardiomyopathy

A case of right adrenal pheochromocytoma masquerading as a dilated cardiomyopathy is described. This patient was normotensive throughout 8 years of observation. Hyperglycemia and an abnormal glucose tolerance test were a clue to the diagnosis which was confirmed by the findings of increased plasma and urinary epinephrine and norepinephrine values. In patients with dilated cardiomyopathy the possibility of a pheochromocytoma should be considered.     

Pronounced depression by propofol on carotid body response to CO2 and K+-induced carotid body activation

Propofol is a commonly used anesthetic agent, and it attenuates hypoxic ventilatory response in humans. Propofol reduce in vivo and in vitro carotid body responses to hypoxia as well as to nicotine in experimental animals. In the present study we examined the effects of propofol on carotid body responses to hypercapnia and K(+)-induced carotid body activation and compared these effects with hypoxia in an in vitro rabbit carotid body preparation. Hypoxia, hypercapnia and potassium increased the carotid sinus nerve activity and propofol attenuated the chemoreceptor responses to all three stimuli. However, the magnitude of propofol-induced attenuation was greater for hypercapnic and K(+)-induced carotid body activation compared to the hypoxic response. These observations suggest that propofol-induced attenuation of the hypoxic response is partly secondary to depression of chemoreceptor response to hypercapnia inhibiting the synergistic interactions between O(2) and CO(2) and may involve CO(2)/H(+) sensitive K(+) channels.     

A simplified, sensitive immunohistochemical detection system employing signal amplification based on fluorescyl-tyramide/antifluorescein antibody reaction: its application to pathologic testing and research.

The catalyzed signal amplification (CSA) technique, based on the peroxidase-mediated deposition of haptenized tyramide and also known as tyramide signal amplification and catalyzed reportor deposition systems, is widely accepted as a signal amplification method for immunohistochemistry and in situ hybridization. In this study, we examined the applicability of a new simplified CSA system employing fluorescyl-tyramide (FT) to pathologic testing and research with formalin-fixed, paraffin-embedded tissues. By using the FT, instead of biotinyl-tyramide (BT) that is commonly employed in the CSA system with chromogen, nonspecific staining caused by endogenous biotin was completely avoided. The FT-CSA system loaded on the automated immunostaining equipment also allowed for more reproducible detection in short times. When applied to cyclin D1 immunostaining that is important in differentiation among small B-cell lymphomas, the system was useful in demonstrating its protein expression in mantle cell lymphomas considered negative or equivocally positive for cyclin D1 in a conventional immunodetection. In immunohistochemistry for phosphorylated proteins and murine hematologic markers that often require higher sensitivity than conventional methods, the FT-CSA system provided desirable staining results with intense signal amplification. Our results indicate that the simplified CSA system employing the FT can be useful in enlarging the target range for routine immunohistochemistry due to its high applicability.     

Dose-related increases in quantitative values for altered hepatocytic foci and cytochrome P-450 levels in the livers of rats exposed to phenobarbital in a medium-term bioassay

The dose-response relationship between liver tumor promoting activity and cytochrome P-450 (CYP) induction by phenobarbital sodium (PB) was investigated using the liver medium-term bioassay system of Ito. Two weeks after a single dose of N-nitrosodiethylamine (DEN) (200 mg/kg body weight, i.p.), rats were given PB at dietary levels of 500, 250, 125, 60, 30, 15 and 8_parts per million (ppm) for 6 weeks. All rats were subjected to partial hepatectomy at week 3, and were killed at week 8. Quantitative values for glutathione S-transferase placental form positive hepatocytic (GST-P⁺) foci were increased in the high dose groups dose-dependently. In contrast, the values in the low dose groups were rather lower than that of the control. CYP2B1, 2C6 and 3A2 were predominantly immunostainable in hepatocytes around the central vein. While Western blotting revealed CYP2B1 and 2C6 proteins to be increased with strict dose-dependence, CYP3A2 was only elevated at high doses. Thus, a good correlation between increase of GST-P⁺ foci and CYP3A2 induction was observed, as well as with CYP2B1 and 2C6 in high dose groups.     

Laparoscopic management of common bile duct stones: transcystic approach and choledochotomy

The purpose of this study was to review our experience with laparoscopic common bile duct (CBD) exploration by the transcystic approach and choledochotomy. We selected the transcystic approach for patients whose CBD stones were less than five in number and smaller than 9 mm in diameter, and whose CBD was less than 15 mm in diameter on cholangiograms. Among 217 patients with CBD stones treated laparoscopically, the transcystic approach was performed successfully in 91 of 104 patients in whom it was attempted (87.5%). The other 126 patients underwent laparoscopic choledochotomy, followed by ductal closure with transcystic drainage in 59, T-tube drainage in 46, primary ductal closure in 19, and choledochoduodenostomy in 1. Choledochotomy was converted to open surgery in only 1 patient. The transcystic approach was associated with shorter hospital stay and less morbidity than choledochotomy. However, choledochotomy also had an acceptably low rate of complications. Bile leaks occurred more frequently in those with primary ductal closure than in those with transcystic drainage or T-tube drainage. Residual stones were found in 2 patients with the transcystic approach and in 10 with choledochotomy. The residual stones were removed through the T-tube tract by choledochoscopy in 7 of these 10 patients. From these results we conclude that laparoscopic management of CBD stones is feasible for almost all patients with CBD stones. It is considered to be safe and effective and has the advantage of being a single-stage procedure. Received: July 7, 2000 / Accepted: October 26, 2000     

Isolation of a Novel Gene Showing Reduced Expression in Metastatic Colorectal Carcinoma Cell Lines and Carcinomas

To investigate genes involved in mctastatic stages of cancer, we analyzed expression of mRN As in three cell lines derived from murine colon adenocarcinoma 26 by means of a differential display method. Each of these lines exhibits distinct metastatic characteristics. Among many bands representing different expression patterns in the display, we confirmed by northern analysis that a gene corresponding to one amplified fragment, termed grm2 (gene related to metastasis 2), was expressed more abundantly in NL4, the derivative with the lowest metastatic potential, than in cell lines NL17, an experimentally metastatic derivative, and in NL22, a spontaneously metastatic derivative. Using thegrm.2 fragment as a probe, we isolated murine cDNA clones and subsequently human cDNA clones corresponding to the GRM2 gene. The human and mouse homologues both encode proteins of 600 amino-acid residues, which show weak homologies to proteins belonging to the myosin family. When we examined the expression levels of this novel gene in human colon cancers and in corresponding metastatic foci, we found that in more than half of these tissues, expression was significantly reduced in association with malignant potential. Our resultsimply that in humans the GRM2 gene product may regulate the metastatic phenotype of some colorectal cancers.