Radiation exposure for human Mars exploration

One major obstacle to human space exploration is the possible limitations imposed by the adverse effects of long-term exposure to the space environment. Even before human space flight began, the potentially brief exposure of astronauts to the very intense random solar energetic particle events was of great concern. A new challenge appears in deep-space exploration from exposure to the low-intensity heavy-ion flux of the galactic cosmic rays since the missions are of long duration, and accumulated exposures can be high. Because cancer induction rates increase behind low to moderate thicknesses of aluminum shielding, according to available biological data on mammalian exposures to galactic cosmic ray-like ions, aluminum shield requirements for a Mars mission may be prohibitively expensive in terms of mission launch costs. Alternative materials for vehicle construction are under investigation to provide lightweight habitat structures with enhanced shielding properties. In the present paper, updated estimates for astronaut exposures on a Mars mission are presented and shielding properties of alternative materials are compared with aluminum.

Safety and usefulness of percutaneous transhepatic cholecystoscopy examination in high-risk surgical patients with acute cholecystitis

BACKGROUND

The aim of the present study was to evaluate the diagnostic and therapeutic usefulness of percutaneous transhepatic cholecystoscopy in high-risk surgical patients with acute cholecystitis.

METHODS

Between January 1992 and June 1998, there were 33 consecutive patients who underwent percutaneous transhepatic cholecystostomy and subsequent percutaneous transhepatic cholecystoscopy for the management of acute cholecystitis.

RESULTS

Percutaneous transhepatic cholecystostomy and subsequent percutaneous transhepatic cholecystoscopy were successfully accomplished in all 33 patients. During percutaneous transhepatic cholecystoscopy, minor complications (2 episodes of minor bleeding during electrohydraulic lithotripsy, 2 of tube dislodgement, and 1 of bile leakage to peritoneum) occurred in 5 patients. Percutaneous transhepatic cholecystoscopy revealed gallstones in 26 cases, sludge ball in 3, gallbladder carcinoma in 3, and 1 case of clonorchiasis related with acute cholecystitis. The 3 gallbladder cancers which were not identified radiologically were found incidentally during percutaneous transhepatic cholecystoscopy. For the 26 patients with gallstones, percutaneous transhepatic cholecystoscopy and concomitant stone removal were successful in 1 to 4 consecutive sessions (mean 2.2 sessions). Gallstones recurred in 3 of 22 patients (14%) during the mean follow-up period of 27 months. All of them remain asymptomatic.

CONCLUSION

Percutaneous transhepatic cholecystostomy may be justified in the management of acute cholecystitis in selected patients with high surgical risk.

Cholangioscopic findings in bile duct tumors

BACKGROUND

Cholangioscopy has been used in the treatment of bile duct stones and the diagnosis of various bile duct tumors. However, the cholangioscopic characteristics of the various types of bile duct tumors have not been clearly described. We analyzed the results of cholangioscopic examinations and classified the findings according to tumor histology.

METHODS

Cholangioscopic findings from 111 patients with benign or malignant bile duct tumors were reviewed. The mucosal changes, the presence of neovascularization, and the patterns of luminal narrowing were analyzed and compared with the histologic diagnosis.

RESULTS

Bile duct adenocarcinoma can be classified into 3 different types according to the cholangioscopic findings: nodular, papillary, and infiltrative. Bile duct adenoma, hepatocellular carcinoma and other types of bile duct cancer such as mucin-hypersecreting cholangiocarcinoma, biliary cystadenocarcinoma, and squamous cell carcinoma also presented unique cholangioscopic characteristics.

CONCLUSIONS

Bile duct tumors exhibit characteristic cholangioscopic findings and cholangioscopy seems to be useful for differential diagnosis.

Cost analysis of transthoracic cardioversion of atrial fibrillation with and without ibutilide pretreatment

BACKGROUND

Ibutilide may result in chemical cardioversion of atrial fibrillation and facilitates transthoracic cardioversion by lowering the defibrillation energy requirement. Whether routine pretreatment with ibutilide increases or decreases the cost of cardioversion is unknown. The purpose of this study was to compare the cost of outpatient transthoracic cardioversion of atrial fibrillation with and without ibutilide pretreatment.

METHODS

Using a model based on published literature and hospital accounting information, a hypothetical group of 100 patients with atrial fibrillation and a left ventricular ejection fraction >0.30 underwent 2 strategies of outpatient cardioversion: transthoracic cardioversion with and without routine pretreatment with 1 mg ibutilide, and with and without involvement of an anesthesiologist for sedation. If transthoracic cardioversion was unsuccessful in patients who did not receive ibutilide, transthoracic cardioversion was repeated after administration of ibutilide.

RESULTS

If an anesthesiologist was involved, transthoracic cardioversion with ibutilide was associated with incremental cost-savings as the efficacy of ibutilide alone in restoring sinus rhythm increased above the critical values of 20%, 27%, and 35% when the efficacy of transthoracic cardioversion alone was 60%, 80%, and 100%, respectively. In the absence of an anesthesiologist, routine pretreatment with ibutilide increased the cost of cardioversion at all success rates of transthoracic cardioversion.

CONCLUSIONS

In the presence of an anesthesiologist, whether or not routine pretreatment with ibutilide lowers the mean cost of cardioversion is determined by the success rates of chemical cardioversion with ibutilide and transthoracic cardioversion. In the absence of an anesthesiologist, ibutilide pretreatment increases the cost of cardioversion.

A new strategy to predict the neoplastic polyps of the gallbladder based on a scoring system using EUS

BACKGROUND

A new method to predict neoplastic polyps of the gallbladder using a scoring system based on five endoscopic ultrasonography (EUS) variables is presented.

METHODS

EUS data from patients with gallbladder polyps who were to undergo cholecystectomy were used for the construction of an EUS scoring system in polyps between 5 and 15 mm in diameter (reference group). The EUS scoring system developed from those patients was applied to other patients (validation group).

RESULTS

In the reference group, size was the most significant predictor of neoplastic polyp. All polyps 5 mm or less in diameter were non-neoplastic and 94% of polyps of greater than 15 mm were neoplastic in the reference group. For polyps between 5 and 15 mm in diameter, the area under the receiver-operating characteristic curves (ROC) plots for the endoscopic scoring system was significantly greater than that under the ROC plots for polyp size alone (p < 0.01). In the validation group, the risk of neoplastic polyp was significantly higher for polyps with a score of 6 or greater compared with those with a score of less than 6 (p < 0.01).

CONCLUSIONS

Our data show that a score based on five EUS variables identifies those patients at risk of neoplasia when polyps are between 5 and 15 mm in diameter. (Gastrointest Endosc 2000;52:372-9).

Expression of matrix metalloproteinases and their inhibitors by rat NK cells: inhibition of their expression by genistein

In this study, we describe rat NK cell-derived MMPs including membrane-type MMPs (MT-MMPs) and tissue inhibitors of MMP (TIMPs). RT-PCR analysis from cDNA of rat A-NK cells revealed mRNA for MMP-2, MMP-9, MMP-7, MMP-10, MMP-11, MMP-13, MT1-MMP, MT2-MMP, TIMP-1, and TIMP-2. The RNK-16 cells expressed mRNA for MMP-7, MMP-10, MMP-11, MT1-MMP, MT2-MMP, TIMP-1, and TIMP-2, in addition to MMP-3 and MMP-13. Western blot analysis confirmed proteins for MT1-MMP and MT2-MMP in RNK-16 cells. TIMP-1 in rat A-NK cells was present at molecular mass of 34-kDa protein which may represent a highly glycosylated form. Genistein, a natural isoflavone found in soybeans, inhibited proliferation of RNK-16 cells in dosage dependent manner. In addition, it down-regulated the expression of MMP-13, MT1-MMP, TIMP-1 and TIMP-2. Moreover, genistein greatly impaired the ability of RNK-16 cells to invade through a model basement membrane. This effect might be mediated by the observed down-regulation of MMP-13 and MT1-MMP.

Anaerobic bacteria and intrahepatic stones: detections of Clostridium sp. and Bacteroides fragilis

OBJECTIVE

To detect anaerobic bacteria Clostridium sp. and Bacteroides fragilis in intrahepatic stones by molecular genetic method.

METHODS

DNA was extracted from 59 stone samples and subjected to polymerase chain reaction (PCR) amplification targeting the 16S rRNA gene of Clostridium sp. and the glutamine synthetase gene of Bacteroides fragilis. Single-strand conformational polymorphism (SSCP) analysis was performed to identify the Clostridium sp.

RESULTS

16S rRNA gene sequences for Clostridium sp. were identified in 49 stones (83%, 49/59). The two most common groups were detected in 19 (41%) and 17 (37%) of the 46 samples using SSPC analysis, and 25/59 (42%) stones were tested positive for Bacteroides fragilis.

CONCLUSIONS

Anaerobes such as Clostridium sp. and Bacteroides fragilis present in intrahepatic stones and may play a role in stone formation. PCR is a useful technique to detect fastidious pathogens, which are difficult to culture. SSCP of PCR products is a rapid method in differentiating bacterial species.

Effect of Fiber-Polymer Interactions on Fracture Toughness Behavior of Carbon Fiber-Reinforced Epoxy Matrix Composites

The effect of anodic oxidation on high-strength polyacrylonitrile-based carbon fibers has been studied in terms of fiber surface energetics and fracture toughness of the composites. According to contact angle measurements based on the wicking rate of a test liquid, anodic oxidation leads to an increase in surface free energy, mainly due to the increase of its specific (or polar) component. For the carbon-fiber-reinforced epoxy resin matrix system, a direct linear relationship is shown between the specific component and the critical stress intensity factor measured by the single edge notched beam fracture toughness test. From a surface-energetic point of view, the anodic treatment may be suitable for carbon fibers incorporated in a polar organic matrix, resulting in an increased specific component of the surface free energy. Good wetting plays an important role in improving the degree of adhesion at interfaces between fibers and matrices of the resulting composites. Copyright 2000 Academic Press.

Diagnostic value of tachycardia features and pacing maneuvers during paroxysmal supraventricular tachycardia

OBJECTIVES

The purpose of this prospective study was to quantitate the diagnostic value of several tachycardia features and pacing maneuvers in patients with paroxysmal supraventricular tachycardia (PSVT) in the electrophysiology laboratory.

BACKGROUND

No study has prospectively compared the value of multiple diagnostic tools in a large group of patients with PSVT.

METHODS

One hundred ninety-six consecutive patients who had 200 inducible sustained PSVTs during an electrophysiology procedure were included. The diagnostic values of four baseline electrophysiologic parameters, nine tachycardia features and five diagnostic pacing maneuvers were quantified.

RESULTS

The only tachycardia characteristic that was diagnostic of atrioventricular (AV) nodal reentry was a septal ventriculoatrial (VA) time of <70 ms, and no pacing maneuver was diagnostic for AV nodal reentry. An increase in the VA interval with the development of a bundle branch block was the only tachycardia characteristic that was diagnostic for orthodromic tachycardia, but it occurred in only 7% of all tachycardias. An atrial-atrial-ventricular response upon cessation of ventricular overdrive pacing was diagnostic of atrial tachycardia, and this maneuver could be applied to 78% of all tachycardias. Burst ventricular pacing excluded atrial tachycardia when the tachycardia terminated without depolarization of the atrium, but the result could be obtained only in 27% of patients.

CONCLUSIONS

This prospective study quantitates the diagnostic value of multiple observations and pacing maneuvers that are commonly used during PSVT in the electrophysiology laboratory. The findings demonstrate that diagnostic techniques rarely provide a diagnosis when used individually. Therefore, careful observations and multiple pacing maneuvers are often required for an accurate diagnosis during PSVT. The results of this study provide a useful reference with which new diagnostic techniques can be compared.

Detection of Helicobacter pylori DNA in human biliary tree and its association with hepatolithiasis

Recently, several authors have reported that Helicobacter pylori DNA has been found in human bile. The aim of this study is to investigate the presence of H. pylori in the biliary tree of Koreans, including the bile, biliary epithelium, and gallstones. This study analyzed intrahepatic bile, bile duct tissue, and gallstones from 43 patients with hepatobiliary disease (PTCS group), gallbladder bile and tissue from 23 patients with gallbladder disease (CCT group), and eight patients without hepatobiliary disease (control group). H. pylori was examined by PCR with two different primers. PCR was positive in 4/43 (9.3%) by 26 kDa protein antigen primer and in 5/43 (11.6%) by urease A gene primer in bile from the PTCS group. However, in intrahepatic duct tissue, PCR was positive in only one case. PCR of gallbladder bile, tissue, and intrahepatic duct stones was negative. Upon intrahepatic bile analysis, the pH was significantly lower in PCR-positive than in negative cases (P < 0.05). In conclusion, H. pylori DNA may be present in the bile when there are certain environmental changes, such as lowered pH; however, H. pylori does not colonize the bile duct epithelium. We could find no pathogenetic role for H. pylori in the formation of hepatolithiasis.

Effect of chronic amiodarone therapy on defibrillation energy requirements in humans

INTRODUCTION

The effect of oral amiodarone therapy on defibrillation energy requirements in patients with an implantable defibrillator has not been established.

METHODS AND RESULTS

Twenty-one consecutive patients with implantable biphasic waveform defibrillators underwent a step-down determination of the defibrillation energy requirement 211 +/- 12 days before and 73 +/- 22 days after initiation of amiodarone therapy (mean total dose 26.7 +/- 11.1 g). Serum amiodarone and desethylamiodarone concentrations were measured at the time of defibrillation energy requirement determination. The mean defibrillation energy requirement before amiodarone therapy was 9.9 +/- 4.6 J. After initiation of amiodarone therapy, the mean defibrillation energy requirement increased to 13.7 +/- 5.6 J (P = 0.004). A linear relationship between the amiodarone (P = 0.02, r = 0.6), desethylamiodarone (P = 0.02, r = 0.6), and combined amiodarone-desethylamiodarone concentrations (P = 0.01, r = 0.6) and the defibrillation energy requirement was noted. Stepwise regression analysis demonstrated that the combined amiodarone-desethylamiodarone concentration was the only independent predictor of increase in the defibrillation energy requirement.

CONCLUSION

Chronic oral amiodarone therapy increases the defibrillation energy requirement by approximately 62% in patients with an implantable defibrillator. The combined amiodarone-desethylamiodarone concentration is directly related to the increase in the defibrillation energy requirement.

Detection of Helicobacter pylori DNA in human biliary tree and its association with hepatolithiasis

Recently, several authors have reported that Helicobacter pylori DNA has been found in human bile. The aim of this study is to investigate the presence of H. pylori in the biliary tree of Koreans, including the bile, biliary epithelium, and gallstones. This study analyzed intrahepatic bile, bile duct tissue, and gallstones from 43 patients with hepatobiliary disease (PTCS group), gallbladder bile and tissue from 23 patients with gallbladder disease (CCT group), and eight patients without hepatobiliary disease (control group). H. pylori was examined by PCR with two different primers. PCR was positive in 4/43 (9.3%) by 26 kDa protein antigen primer and in 5/43 (11.6%) by urease A gene primer in bile from the PTCS group. However, in intrahepatic duct tissue, PCR was positive in only one case. PCR of gallbladder bile, tissue, and intrahepatic duct stones was negative. Upon intrahepatic bile analysis, the pH was significantly lower in PCR-positive than in negative cases (P < 0.05). In conclusion, H. pylori DNA may be present in the bile when there are certain environmental changes, such as lowered pH; however, H. pylori does not colonize the bile duct epithelium. We could find no pathogenetic role for H. pylori in the formation of hepatolithiasis.

2B4 stimulation of YT cells induces natural killer cell cytolytic function and invasiveness

2B4 is a surface molecule found on all human natural killer (NK) cells, a subset of CD8+ T cells, monocytes and basophils. It was originally identified on mouse NK cells and the subset of T cells that mediate non-major histocompatibility complex (MHC)-restricted killing. Recently,9 we have cloned the human homologue of 2B4 (h2B4) and found h2B4 to also mediate non-MHC-restricted cytotoxicity. In this study, we examine h2B4 in regulating various functions of NK cells using a human NK cell line YT, with monoclonal antibody (mAb) C1.7, an antibody that specifically recognizes h2B4. Ligation of surface 2B4 with mAb C1.7 increases YT's ability to destroy tumour cells. In the presence of mAb C1.7, the production of interferon-gamma (IFN-gamma) by YT cells is greatly enhanced. Engagement of surface 2B4 by mAb C1.7 downregulates the expression of h2B4 at the cell surface as well as the expression of h2B4 mRNA. Also, signalling through h2B4 causes the increased expression of matrix metalloproteinase-2, a member of the matrix degrading proteinase family. Thus, in addition to modulating cytolytic function and cytokine production of NK cells, activation through surface 2B4 may play a role in upregulating the machinery for degradation of extracellular matrices to promote invasion of the tumour by NK cells.

Phosphorylation of the rat vesicular acetylcholine transporter

Metabolic labeling of a mutant PC12 cell line, A123.7, expressing recombinant rat vesicular acetylcholine transporter (VAChT) with radiolabeled inorganic phosphate was used to demonstrate phosphorylation of the transporter on a serine residue. Mutational analysis was used to demonstrate that serine 480, which is located on the COOH-terminal cytoplasmic tail, is the sole phosphorylation site. Phosphorylation of serine 480 was attributable to the action of protein kinase C. Using a permanently dephosphorylated form of rat VAChT, S480A rVAChT, it was shown that this mutant displays the same kinetics for the transport of acetylcholine and the binding of the inhibitor vesamicol as does the wild type transporter. However, sucrose gradient density centrifugation showed that, unlike wild type VAChT, the S480A mutant did not localize to synaptic vesicles. These results suggest that phosphorylation of serine 480 of VAChT is involved in the trafficking of this transporter.

Secreted and membrane-associated matrix metalloproteinases of IL-2-activated NK cells and their inhibitors

We have previously documented that rat IL-2-activated NK (A-NK) cells produce matrix metalloproteinase-2 (MMP-2) and MMP-9. In this study, we describe mouse A-NK cell-derived MMPs, including MT-MMPs, and also TIMPs. RT-PCR analysis from cDNA of mouse A-NK cells revealed mRNA for MMP-2, MMP-9, MMP-11, MMP-13, MT1-MMP, MT2-MMP, TIMP-1, and TIMP-2. MMP-2 and MMP-9 expression was confirmed by gelatin zymography. Moreover, we report for the first time that MT-MMPs are expressed by NK cells, i.e., large granular lymphocytes as determined by both RT-PCR and Western blots. TIMP-1 expression was detected as a 29-kDa protein in Western blots. It is intriguing that TIMP-2 protein from A-NK cells was also detected as a 29-kDa protein, which is clearly different from the previously reported molecular mass of 21 kDa in mouse and human cells. In addition, inhibition of MMPs by BB-94, a selective inhibitor of MMP, significantly inhibited the ability of mouse A-NK cells to migrate through Matrigel, a model basement membrane. Taken together, these findings suggest that A-NK cells may therefore use multiple MMPs in various cellular functions, including degradation of various extracellular matrix molecules as they extravasate from blood vessels and accumulate within cancer metastases following their adoptive transfer.

Primary stenting for acute myocardial infarction via the transradial approach: a safe and useful alternative to the transfemoral approach

BACKGROUND

Primary stenting in acute myocardial infarction (AMI) has been demonstrated to reduce recurrent ischemic events. However, transradial stenting in AMI has not been well established. Therefore, we sought to investigate the feasibility and utility of transradial coronary stenting in patients with AMI.

METHODS

From April 1998 to April 1999, 56 patients (43 male; mean age of 57 years) who arrived within 6 hours of pain onset with culprit vessel size > 2.5 mm constituted this study. The transradial approach (Group 1) was used in 30 patients with hemodynamically stable and palpable right radial pulse. The transfemoral approach (Group 2) was used for vascular access in the remainder of patients (26) who might have required a second vascular access site for intraaortic balloon pumping (in cardiogenic shock) and/or a transvenous temporary pacemaker.

RESULTS

Overall success rate was achieved in 54 of 56 patients (96%). The success rate was 90% (27/30) in Group 1 and 96% (25/26) in Group 2. The cannulation time (from patient arrival at the catheterization room to the time of arterial cannulation) and the total procedure time (from patient arrival at the catheterization room to the completion of the procedure) were not significantly different between Group 1 and Group 2 (9.2+/-5.3 versus 8.9+/-5. 8 minutes, p>0.05; 53.7+/-19.4 versus 57.5 +/-26.8 minutes, p>0.05, respectively). In the Group 1 patients, there was no forearm ischemia or loss of radial pulse during the 30-day follow-up period.

CONCLUSION

Primary coronary stenting for acute myocardial infarction via the transradial approach is a safe and feasible alternative to the conventional transfemoral approach, and is especially useful for hemodynamically stable patients who do not require a second vascular access site.

The effect of clonidine pretreatment on the perioperative proinflammatory cytokines, cortisol, and ACTH responses in patients undergoing total abdominal hysterectomy

We investigated the hypothesis that oral clonidine premedication would decrease the release of proinflammatory cytokines interleukin (IL)-6, IL-1beta, and tumor necrosis factor-alpha, and stress hormones cortisol and adrenocorticotropic hormone (ACTH), in patients who underwent total abdominal hysterectomy. Twenty patients were randomly assigned to one of two groups: the control group received no premedication, whereas the treatment group received clonidine 0.15 mg oral dose 90 min before surgery. Venous blood samples were obtained at preinduction time and immediately, 1, and 3 h after the start of surgery. IL-6 increased significantly at 3 h, and cortisol and ACTH at 1 and 3 h after the start of surgery compared with the baseline values within both groups. IL-1beta levels decreased at all times compared with the baseline value in the control group. In the comparison study between the control group and the clonidine group, there was a significant decrease in IL-6 level 3 h after the start of surgery and IL-1beta at preinduction time in the clonidine group, whereas there were no changes in tumor necrosis factor-alpha, cortisol, and ACTH levels. These results show that clonidine modulates the IL-6 response related to surgical stress.

IMPLICATIONS

We assessed the effect of the alpha(2)-adrenoreceptor agonist clonidine on the immunoendocrine activity during the perioperative period. Clonidine 0.15 mg given as oral premedication resulted in the reduced Interleukin-6 production in response to total abdominal hysterectomy.

Clinical breast examination for screening of asymptomatic women: the importance of clinical breast examination for breast cancer detection

Of 489 asymptomatic women who were referred to our institute from other screening clinics, 46 were eventually proven to be breast cancer patients, and this number equated to 8.1% of the 565 breast cancer patients treated in our institute during the period of January 1997 to December 1998. Among the 46 cancer patients of the initial 489 asymptomatic women, twenty-five (54.35%) were detected by mammogram alone, six (13.04%) by clinical breast examination (CBE) alone, and the remaining 15 (32.61%) by both mammogram and CBE. In context with age, the mammographic sensitivity for cancer detection was 100% for women aged over 60, 91% for 50s, 78.9% for 40s, and 75% for 30s, and inversely correlated with the patient's age. Among the 25 cancers detected by mammogram alone, 18 (72%) belonged to DCIS or stage I. In contrast, four (66.7%) of six cancers detected by CBE alone and nine (60%) of 15 cancers by both CBE and mammography were included in stage IIa or IIb. However, the total incidence of early cancers (stages 0 and I) was significantly higher in the screening group than in the symptomatic group (p < 0.01). These results suggest that the role of mammography is important in the detection of cancers in their earlier stage and CBE is helpful in reducing false negative results in breast cancer screening. In conclusion, film mammography is the best tool for the detection of microcalcification and is useful for the detection of earlier lesions, but is not perfect for the detection of breast cancer particularly in young women. A careful CBE is an essential part of breast screening in order to reduce false-negative results.

A case of membranoproliferative glomerulonephritis associated with a hydatidiform mole

We treated a 54-year-old woman who was suffering from membranoproliferative glomerulonephritis associated with a complete type of hydatidiform mole. The renal manifestations were proteinuria and hematuria. A renal biopsy, performed before gynecologic management, disclosed focal and segmental subendothelial deposits with a proliferation of the mesangial cell and showed irregularly thickened capillary loops by light and electronmicroscoy. Genralized edema, proteinuria and hematuria were completely recovered by suction and curettage of the hydatidiform mole with prophylactic chemotherapy. The clinical manifestation of earlier presented 3 cases have been the nephrotic syndrome. The common feature of them was a complete remission of the nephropathy after the removal of the hydatidiform mole. The relationship between the hydatidiform mole and glomerulonephritis remains unresolved at present. But we concluded that the hydatidiform mole might be a cause of glomerulonephritis in this case.

Telomerase activity in pure pancreatic juice for the diagnosis of pancreatic cancer may be complementary to K-ras mutation

BACKGROUND

The usefulness of K-ras mutation in pancreatic juice for the diagnosis of pancreatic cancer is questionable. Telomerase is positive in pancreatic cancer but rarely in benign pancreatic diseases. We conducted this study to determine the usefulness of K-ras mutation and telomerase activity in pancreatic juice for the diagnosis of pancreatic cancer.

METHODS

Pancreatic juice collected during endoscopic retrograde cholangiopancreatography was examined in 31 patients: 12 with pancreatic cancer, 11 with chronic pancreatitis, and 8 control patients. The K-ras gene was detected by using the restriction fragment length polymorphism method. Telomerase activity was detected by using the telomeric repeat amplification protocol.

RESULTS

K-ras mutation was positive in 75% (9 of 12) of pancreatic cancers and in 27% (3 of 11) of cases of chronic pancreatitis but in none of the control patients. Telomerase activity was detected in 92% (11 of 12) of pancreatic cancers and in 18% (2 of 11) of cases of chronic pancreatitis. The diagnostic value in pancreatic cancer was comparable between K-ras mutation and telomerase when evaluated separately. However, by combining these 2 methods, the specificity rose to 100%.

CONCLUSIONS

For the diagnosis of pancreatic cancer, telomerase activity in pancreatic juice may possibly be complementary to K-ras mutation because it may decrease the rate of false-positive diagnosis.

Seasonal biochemical plasticity of a flight muscle in a bat, Murina leucogaster

Cellular and biochemical responses of the pectoral muscle to variation in seasonal activity were studied in the bat, Murina leucogaster ognevi. We collected bats in mid-hibernation (February), end-hibernation (April), and mid-summer (August) to track major activity periods in their annual cycle. Our findings indicated that myofiber cross-sectional area decreased to 68% between mid- and end-hibernation, but returned to the winter level in mid-summer. Total soluble protein and total RNA concentrations were not altered over these sampling periods. Oxidative potential gauged by citrate synthase activity increased 1.47-fold from mid- to end-hibernation and then remained at the similar level in mid-summer. Glycolytic potential gauged by lactate dehydrogenase activity changed little between mid- and end-hibernation but increased 1.42-fold in summer, compared with the winter level. Thus, the myofibers underwent disuse atrophy during hibernation, while enzymatic catalytic function recovered towards the level of mid-summer.

Inhibitory effect of anaphylactic shock by caffeine in rats

Caffeine is known to reduce evoked histamine secretion, but the effects of caffeine on anaphylactic shock have not been clarified. We have investigated the effects of caffeine on anaphylactic shock in rats. Systemic anaphylactic shock by compound 48/80 injection was monitored for 1 h. An IgE-dependent local anaphylactic shock was generated by sensitizing the skin with anti-dinitrophenyl (DNP) IgE followed 48 h later with an injection of antigen. Caffeine inhibited compound 48/80-induced anaphylatic shock to 40% with a dose of 1 mg/kg. Caffeine (0.1 mg/kg) inhibited to 56.4+/-0.4% passive cutaneous anaphylactic shock activated by anti-DNP IgE. Caffeine (5-20 mM) significantly inhibited histamine release from rat peritoneal mast cells (RPMCs) activated by compound 48/80 or anti-DNP IgE. Especially, caffeine (20 mM) inhibited by 96.7+/-0.5% histamine release activated by compound 48/80. Moreover, caffeine (1-20 mM) had a significant inhibitory effect on anti-DNP IgE-induced tumor necrosis factor-alpha production from RPMCs. The level of cAMP in RPMCs, when caffeine (20 mM) was added, increased significantly after 5-60 min compared with that of a normal control. These results indicate that caffeine inhibits immediate-type allergic reactions by inhibition of mast cell degranulation in vivo and in vitro.