Malignancy in choledochal cysts

BACKGROUND/AIMS

Malignancy in choledochal cysts is a rare condition. This study presents our experience with this condition, with emphasis on the clinical presentation, management and outcome.

METHODOLOGY

Subjects included 80 adults with choledochal cysts treated from January 1979 to December 1995. Of these patients, 8 were found to have malignancy in the cyst and formed the basis of this study.

RESULTS

Four patients had synchronous and 4 had metachronous carcinoma lesions arising in the choledochal cyst. The clinical presentation was: biliary tract infection in 5 patients, gastric outlet obstruction in 2 and right upper quadrant pain and body weight loss in 1. Operations for bile duct malignancy included total excision in 2 patients, choledochotomy with T-tube drainage in 2 patients, gastrojejunostomy in 2 patients, percutaneous transhepatic biliary drainage and gastrojejunostomy in 1 patient and metastatic lymph node biopsy only in 1. One patient died due to septic shock within 30 days of the operation (operative mortality). Postoperative survival time ranged from 4-13 months with a mean of 6.2 months.

CONCLUSIONS

The frequency of malignancy in the choledochal cysts was 10% in the present series. Malignancy in the choledochal cyst should be highly suspected in patients with cholangitis symptoms, body weight loss and anemia. Prognosis in this disease entity is poor.

Selective inhibition of inducible nitric oxide in ischemia-reperfusion of rat small intestine

PURPOSE

We investigated the role of constitutive and inducible nitric oxide (NO) synthases in intestinal ischemia-reperfusion (I/R) injury by observing the alterations in hemodynamics and intestinal microcirculation in response to I/R in rats, with or without inhibitors of NO synthases.

METHODS

Adult male Sprague-Dawley rats (n = 9/group) received a standard I/R procedure alone: I/R plus intravenous administration of aminoguanidine (an inhibitor of inducible NO synthase); I/R plus L-NAME (NG-nitro-L-arginine methyl ester, an inhibitor of constitutive and inducible NO synthase); IR + L-Arg (L-arginine, an NO precursor); or a sham operation plus the vehicle. The I/R procedure was performed by clamping the perfusion vessels of a segment of the terminal ileum, and medication was administered intravenously before and after intestinal ischemia. The intestinal perfusion and leukocyte-endothelial interactions were evaluated with in vivo microscopy and laser Doppler flowmetry. Surface expression of CD11b (an adhesion molecule) of circulating granulocytes was measured with flow cytometry.

RESULTS

Intestinal I/R produced circulatory alterations, intestinal microcirculatory derangement, energy depletion, and lipid peroxidation. Aminoguanidine significantly attenuated the reperfusion-related depression of mean arterial pressure (MAP), the decrease in intestinal perfusion index, the decrease in tissue ATP preservation, the increase in tissue malondialdehyde (MDA) level, and the expression of CD11b of circulating granulocytes. Administration of L-NAME had only minor and transient effects on reperfusion-related changes of MAP, intestinal flux, numbers of adherent leukocytes, and CD11b expression, but had some protective effects on tissue MDA and adenosine triphosphate levels and flow velocity. L-Arg further decreased the MAP but did not affect reperfusion-related variables.

CONCLUSIONS

Our results show that the selective inhibition of inducible NO synthase by aminoguanidine attenuates the hemodynamic and microcirculatory derangement that results from intestinal I/R.

Arcobacter butzleri bacteremia in a patient with liver cirrhosis

Invasive Arcobacter butzleri infection in humans has been rarely described. We report a 60-year-old man with liver cirrhosis who presented with high fever and esophageal variceal bleeding. Two aerobic blood cultures grew Campylobacter-like organisms. The biochemical reactions of the isolate were inconclusive, while sequence analysis of the 16S rRNA gene definitively identified the organism as A. butzleri. The patient's bleeding stopped after endoscopic sclerosing therapy. Although the organism appeared to be resistant to cephalosporins on the basis of the minimum inhibitory concentrations determined with the E test, the fever resolved with parenteral cefuroxime. Whether the clinical improvement was related to cephalosporin therapy or to the self-limited nature of Arcobacter bacteremia is not known.

A reusable and specific protein A-coated piezoelectric biosensor for flow injection immunoassay

A hydrophilic matrix of periodate-oxidized dextran was used as a double-sided linker to covalently immobilize Staphylococcus aureus protein A (SpA) molecules onto a poly-L-lysine-modified piezoelectric crystal surface to improve their stability, activity, and binding specificity with human immunoglobulin G (IgG) in flow injection assays. The prepared sensing crystals displayed best sensitivity and reusability at a flow rate of 140 microL/min. A human IgG concentration as low as 0.3 nM can be detected by this system. Up to 19 successive assay repetitions were achieved without significant loss of sensitivity using the same crystal. The analysis of adsorption kinetics indicates that such a preparation can greatly increase the amount of available active human IgG binding sites on immobilized SpA. Hardly any response arising from unspecific binding was detected. In addition, the sensing crystal prepared by this method was found to retain activity better than one prepared via direct deposition when stored in either wet or dry states. Finally, the prepared SpA-coated crystals were applied to the affinity immobilization of polyclonal goat anti-Schistosoma japonicum glutathione-S-transferase (GST) and were able to subsequently detect GST and its genetically engineered mutant either in a purified form or in the crude cell lysate.

Use of alternative therapy among pediatric oncology patients in Taiwan

Both alternative medicine and western medicine have been commonly used to treat pediatric cancer patients in Taiwan. Each has its own intrinsic strengths and weaknesses and they can be complementary. Little is known about medical help-seeking behaviors of parents of pediatric cancer patients, especially those related to alternative therapies. This study investigated the extent and parental expectations on use of alternative therapies. All primary caregivers of 63 eligible patients were interviewed. Use of alternative therapies, regardless of education level or social status of their families, is prevalent (n = 46, 73%) in Taiwan. Commonly used alternative therapies included, in order of popularity, formulated functional food (n = 22, 48%), temple worship/shamanism (n = 19, 40%), traditional Chinese medicine (n = 9, 20%), secret recipes/herbs (n = 13, 28%), and diet supplements (n = 9, 19%). Such practices generally occur without medical guidance from oncologists, largely because of poor interactions between parents and oncologists. Future efforts should be made to encourage both parents and oncologists to discuss this issue. Nurses may serve as mediators by developing mutual trust and a sharing relationship between these groups.

The effect of pH on the structure, binding and model membrane lysis by cecropin B and analogs

Cecropins are a group of anti-bacterial, cationic peptides that have an amphipathic N-terminal segment, and a largely hydrophobic C-terminal segment and normally form a helix-hinge-helix structure. In this study, the ability of cecropin B (CB) and two analogs to lyse phospholipid bilayers, which have two levels of anionic content, has been examined by dye-leakage measurements over the pH range 2. 0-12.0. The two analogs differ from the natural peptide by having either two amphipathic segments (CB1) or two hydrophobic segments (CB3). All these peptides (except CB3 on low anionic content bilayers where it is not active) have maximal lytic activity on both types of bilayers at high pH. However, the pattern of secondary structure formation on these bilayers by the peptides, as measured by circular dichroism (CD), and the pattern of their ability to bind lipid monolayers, as measured using a biosensor, do not directly correlate with the pattern of their lytic ability. CB and CB1 with low anionic content bilayers have secondary structures as measured by CD with a similar pattern to membrane lysis, but binding is maximal near neutral, not high, pH. CB3 has some secondary structures on low anionic content bilayers at low pH and this becomes maximal over the basic range, but CB3 neither binds to nor lyses with these lipid layers. On high anionic content lipid layers, all peptides show high levels of secondary structures over most of the pH range and maximal binding at neutral pH (except for CB3, which does not bind). All three peptides lyse with high anionic content bilayers, but show no activity at neutral pH and reach maximal activity at very high pH. This work shows that pH is a major factor in the capability of antibacterial peptides to lyse with liposomes and that secondary structure and binding ability may not be the main determinants.

The skill components of a therapeutic chopsticks task and their relationship with hand function tests

Chopsticks are the primary tools used for eating and the physical movements of control are familiar to Chinese people. Chopsticks are easy to obtain in most rehabilitative settings. Occupational therapists often guide patients to practice miscellaneous chopsticks tasks to increase hand function in any case. The objective of this study was to investigate the skill components of the therapeutic chopsticks task and their relationship with hand function tests, and to identify clinical value. Eighty normal subjects (41 males and 39 females) whose age ranged from 17 to 26 years old participated in this study. Five standard hand function tests including three dexterity tests [Minnesota Rate of Manipulation Test (MRMT), Purdue Pegboard Test, and O'Connor Tweezer Dexterity Test (OTDT)], and two strength tests (Jamar Handgrip Test, and Pinchometer Test) were chosen to measure the dexterity and strength of hands. Additionally, the Test of Chopsticks Manipulation (TCM) was designed and used to assess the chopsticks manipulation skills. Subjects were tested with all the hand function tests and TCM in a random sequence. Results of six tests were obtained for each subject. Factor analysis showed that the skill components of TCM should be categorized into the "dexterity" component. In addition, a significant relationship (p < 0.05) was only seen between TCM and OTDT, there was no significant correlation between TCM and the other hand function tests. Findings in this study are valuable in setting the rehabilitation programs for patients with dexterity problems.

Aminoguanidine attenuates hemodynamic and microcirculatory derangement in rat intestinal ischemia and reperfusion

BACKGROUND

Nitric oxide (NO) participates in the regulation of hemodynamic and microcirculatory changes in intestinal ischemia and reperfusion (I/R). However, the nature of the involvement of an inducible NO release has been controversial. This study evaluates the impact of an inducible NO synthase inhibitor, aminoguanidine, used as a treatment in a rat intestinal I/R model.

METHODS

We investigated the hemodynamics by measuring the mean arterial pressure (MAP), and the microcirculatory responses of the intestine and liver to systemically administered aminoguanidine by use of laser-Doppler flowmetry (LDF), in vivo microscopy, and flow cytometry.

RESULTS

During the 30-min ischemia of the selected 20-cm ileal segment, no MAP change was noted. At reperfusion, a marked decrease of MAP was noted and the lowest levels were noted 3 hours after reperfusion (67 +/- 4% vs. 99 +/- 5% in sham-operated control animals). A marked decrease in liver perfusion as measured by LDF was noted 1 hour after reperfusion and remained low at 5 hours (72 +/- 4% vs. 97 +/- 3% in sham-operated control animals). A marked decrease in intestine perfusion was noted by using LDF 1 hour after reperfusion and remained low at 5 hours (43 +/- 3% vs. 92 +/- 4% in sham-operated control animals). The flow velocity of the postcapillary venules of the intestine was markedly decreased (1.01 +/- 0.62 vs. 2.67 +/- 0.34 mm/s in sham-operated control animals) at 5 hours after reperfusion. The flow velocity of the postsinusoidal venules of the liver was also markedly decreased (1.01 +/- 0.62% vs. 2.67 +/- 0.34% in sham-operated control animals). Leukocyte-endothelial interaction (adhesion) was increased in the postcapillary venules of the intestine (54 +/- 12 vs. 6 +/- 4/microm2 in sham-operated control animals) and in the postsinusoidal venules of the liver (32 +/- 8 vs. 2 +/- 2/microm2 in sham-operated control animals). Concomitantly, the granulocyte count was increased (9.1 +/- 0.6 vs. 2.1 +/- 0.3% of total circulating leukocytes in sham-operated control animals), with an increase of CD 11b expression. Aminoguanidine administration (1 mg/kg) 0.5 hour before ischemia and 1 hour after reperfusion significantly increased MAP, increased intestine and liver perfusion, decreased adhesion, and decreased circulating granulocytes and CD 11b expression.

CONCLUSION

Inhibition of an inducible NO release by aminoguanidine in intestinal I/R can attenuate hemodynamic and microcirculatory derangement.

Neutrophil elastase inhibitor (ONO-5046) attenuates reperfusion-induced hepatic microcirculatory derangement, energy depletion and lipid peroxidation in rats

Microcirculatory derangement, energy depletion, and lipid peroxidation are associated with the development of ischemia-reperfusion injury in the liver. This study investigated the effects of a neutrophil elastase inhibitor (ONO-5046) on hepatic ischemia-reperfusion injury. Adult, male Sprague-Dawley rats were divided into four treatment groups: 1) sham-operated control (laparotomy only, no ischemia) and saline injection (1 mL/kg), n = 6; 2) ischemia control (1-h ischemia, 2-h reperfusion) and saline injection (1 mL/kg), n = 6; 3) intravenous injection with ONO-5046 at a dose of 1 mg/kg 5 min before ischemia and immediately after reperfusion plus 1-h ischemia and 2-h reperfusion, n = 6; and 4) intravenous injection with ONO-5046 at a dose of 10 mg/kg 5 min before ischemia and immediately after reperfusion plus 1-h ischemia and 2-h reperfusion, n = 6. A laser-Doppler flowmeter and in vivo microscopy were used to investigate hepatic microcirculation. Tissue malondialdehyde (MDA) and adenosine triphosphate (ATP) levels were determined at the end of the experiment.

RESULTS

Compared with ischemia alone, ONO-5046 significantly reduced the extent of microcirculatory and hemodynamic derangement after ischemia-reperfusion. ONO-5046 at both doses significantly attenuated decreases in mean arterial pressure. ONO-5046 lessened adherent leukocyte count and improved flow velocity in the sinusoids and postsinusoidal venules. ONO-5046 at the dose of 10m/kg reduced MDA (1.97 +/- 0.54 micromol/g protein vs. 3.58 +/- 1.21 micromol/g protein in the ischemia and reperfusion group) and increased ATP levels (2.62 +/- 0.19 micromol/g wet wt vs. 0.57 +/- 0.37 pmol/g wet wt in the ischemia and reperfusion group), whereas ONO-5046 at a smaller dose (1 mg/kg) had lesser but significant effects on MDA and ATP alterations. This study demonstrates that treatment with ONO-5046, a neutrophil elastase inhibitor, can ameliorate ischemia-reperfusion injury of the rat liver.

Membrane lysis by the antibacterial peptides cecropins B1 and B3: A spin-label electron spin resonance study on phospholipid bilayers

Custom antibacterial peptides, cecropins B1 (CB1) and B3 (CB3), were synthesized. These peptides have particular sequence characteristics, with CB1 having two amphipathic alpha-helical segments and CB3 having two hydrophobic alpha-helical segments. These differences were exploited for a study of their efficacy in breaking up liposomes, which had different combinations of phosphatidic acid (PA) and phosphatidylcholine (PC), and a study of their lipid binding ability. Binding and nonbinding lysis actions of CB1 and CB3 on liposomes were examined further by electron spin resonance (ESR). The spin-labeled lipids 5'SL-PC, 7'SL-PC, 10'SL-PC, 12'SL-PC, and 16'SL-PC were used as probes. The ESR spectra revealed larger outer hyperfine splittings (2A(max)) for CB1 when the interactions of CB1 and CB3 with liposomes were compared. These observations indicate a larger restriction of the motion of the spin-labeled chains in the presence of CB1. Plots of the effective order parameter at the various probe positions (chain flexibility gradient) versus the peptide-lipid ratio further suggested that the lysis action of CB1 is related to its capacity to bind to the lipid bilayers. In contrast, there is no evidence of binding for CB3. To augment these findings, four spin-labeled peptides, C8SL-CB1, C32SL-CB1, C5SL-CB3, and C30SL-CB3, were also examined for their binding to and their state of aggregation within the lipid bilayers. Association isotherms of the peptides were measured for liposomes containing two molar fractions of PA (0.25 and 0.75). The membrane binding of the CB1 peptides exhibited a cooperative behavior, whereas the association isotherm of CB3 revealed binding to the lipid only for beta = 0.75 liposomes. To further identify the location of CB1 in the lipid bilayers, measurements of the collision rate with chromium oxalate in solution were conducted. Results from ESR power saturation measurements suggested that the NH(2)-terminal alpha-helix of CB1 is located on the surface of the lipid bilayers, whereas the COOH-terminal alpha-helix of CB1 is embedded below the surface of the lipid bilayers. These conclusions were further supported by the observed relationship between the partition distribution of peptides bound to liposomes at different PA/PC ratios and the amounts of free peptides. Based on the above observations, possible mechanisms of the bilayer lysis induced by CB1 and CB3 on liposomes of different composition are discussed.

[RAPD method for the identification of intergeneric asymmetric somatic hybrid plants of wheat]

Randomly amplified polymorphic DNA (RAPD) method was used to identify the hybrid nature of three kinds of intergeneric asymmetric somatic hybrid plants of wheat: wheat (Triticum aestivum) + Haynaldia villosa, Wheat + Leymus chinensis and wheat + Agropyron elongatum. It was shown from the electrophoresis profiles that the genome of somatic hybrid plants contained specific section genome of both parents after DNA amplification with arbitrary primers. A specific RAPD product (DNA fragment of 0.77 kbp) of A. elongatum generated with primer OPJ-12 was isolated, purified, labeled and used as a probe. Southern blot from OPJ-12 primer-generated specific section genome of the hybrid (T. aestivum + A. elongatum) hybridized to this probe (0.77 kbp) proved that they are homologous in nature. This paper also discussed the advantage of RAPD method in identification of hybrid plants, especially asymmetric somatic hybrids.

Spinal nitric oxide participates in the control of the blood pressure during graded hemorrhage in the conscious rat

We sought to evaluate the role of spinal nitric oxide (NO) in the control of blood pressure in the conscious animal and determine its possible participation in the progression of hemorrhagic shock. Adult, male Sprague-Dawley rats were chronically prepared with intrathecal, intravenous, and intra-arterial catheters. We first investigated the role of spinal NO on blood pressure control by intrathecal administration of N(G)-nitro-L-arginine methyl ester hydrochloride (L-NAME) at 0.37 micromol, 0.74 micromol. or 1.48 micromol. A dose-related increase in blood pressure was observed. We next pretreated animals with intrathecal or intravenous L-NAME at 0.37 micromol and induced the animal to shock by graded hemorrhage. Animals that received vehicle control or intravenous L-NAME had a decrease in blood pressure after 12% of the total circulatory blood volume (TBV) had been removed and developed severe hypotension after 24% TBV was bled. On the other hand, intrathecal pretreatment of L-NAME significantly attenuated the decrease in blood pressure. The blood pressure was maintained until 40% TBV had been withdrawn. We concluded that inhibition of NO synthase, in the spinal cord, increased blood pressure in a dose-dependent manner, and hemorrhagic shock induced by graded hemorrhage may involve an upregulation mechanism of spinal NO synthase in producing severe hypotension in conscious rats.

Affinity purification of Schistosoma japonicum glutathione-S-transferase and its site-directed mutants with glutathione affinity chromatography and immobilized metal affinity chromatography

A C-terminally polyhistidine-tagged protein of Schistosoma japonicum glutathione-S-transferase, named as SjGST/His, and its Cys85-->Ser, Cys138-->Ser, and Cys178-->Ser site-directed mutants were prepared and highly expressed in Escherichia coli. Both immobilized metal affinity chromatography (IMAC) and glutathione (GSH) affinity chromatography were used to purify these four enzymes. All of them were purified with equal efficiency by Ni2+-chelated nitrilotriacetic acid agarose gel, but not by GSH Sepharose 4B gel. The protein amounts of wild-type and Cys85-->Ser enzymes purified by the latter gel were three to seven-fold greater than those of the other two enzymes purified by the same gel, while their specific activities were two-fold lower, presumably because of the occurrence of noncovalent aggregation. Both purification methods yielded highly pure enzymes, while there were minor amounts of inter- and intra-disulfide forms in the IMAC purified enzymes except for the Cys85-->Ser mutant. Addition of dithiothreitol to GSH-affinity purified enzymes shifted all of their mass spectra of matrix-assisted laser desorption/ionization-time of flight mass spectrometry toward low molecular-mass regions, while addition of GSH to IMAC purified enzymes shifted the spectra toward high molecular-mass regions. The shift values of wild-type enzyme were larger than those of the three mutants, indicating that the Cys85, Cys138, and Cys178 residues were S-thiolated by GSH during the GSH-affinity purification. This result was confirmed by isoelectric focusing. These findings suggest that IMAC is more efficient than the conventional GSH-affinity system for the purification of SjGST/His enzyme, especially for its mutants and fusion proteins.

Intrahepatic cholangiocarcinoma in Taiwan

We report our experience of the surgical treatment of intrahepatic cholangiocarcinoma (ICC) in Taiwanese patients. A total of 162 patients with histologically proven ICC were treated of whom 106 (65. 4%) had associated hepatolithiasis. Patients with hepatolithiasis were in earlier stages than those without hepatolithiasis. Two-thirds of the patients with hepatolithiasis presented with acute cholangitis, and two-thirds of those without hepatolithiasis presented with hepatomegaly. The rate of hepatic resection was 29.6% (48 of 162), and these rates were 31.1% and 26.8% for the patients with and without hepatolithiasis, respectively. Ninety-three percent of the patients with hepatolithiasis underwent common bile duct exploration, compared with 18% of those without hepatolithiasis. The surgical mortality rates were 3.7% (6/162), for all patients, and 3. 8% and 3.6% for patients with and without hepatolithiasis, respectively. The morbidity rate was much higher in the patients with hepatolithiasis (37.7% vs 16.1%). The 1-, 3-, and 5-year survival rates were 35.5%, 20.5%, and 16.5% in the patients with hepatolithiasis and 27.2%, 8.8%, and 7.8% in those without hepatolithiasis. Concomitant hepatolithiasis prevented precise diagnosis preoperatively and precipitated biliary sepsis, which affected resectability and increased postoperative morbidity. Hepatolithiasis per se did not influence long-term survival.

Secondary structure formation is the earliest structural event in the refolding of an all beta-sheet protein

The refolding kinetics of cobrotoxin (CBTX), a small-molecular-weight ( approximately 7 kDa) all beta-sheet protein, has been monitored using a variety of biophysical techniques. The secondary structure formation and hydrophobic collapse occur as distinct events during the refolding of the protein. Complete secondary structure formation occurs prior to the clustering of the hydrophobic residues. The late stage(s) of the refolding pathway of CBTX is characterized by change(s) in the local environment and optical asymmetry of the indole ring of the sole tryptophan residue. The results obtained in the present study, to our knowledge, represent the first unambiguous experimental support for the framework model of protein folding.

[Induction of programmed cell death by menadione in suspension culture of carrot cells]

Menadione (VK3), a quinone that undergoes redox cycles leading to the formation of superoxide radicals, was found to induce cell death in suspension culture of carrot cells. The effect of menadione was in a dose-dependent manner. 100-800 mumol/L menadione caused 10-33 percent cell death. When concentration of menadione reached 1 mmol/L, 100 percent of cell death was observed. DNA cleavage, a hallmark of apoptosis was further studied. DNA ladders were observed in cells treated with 600 and 800 mumol/L menadione but not with lower concentration treatments where only very low percentage of cell death was found. There was no DNA ladders in the cells treated with 1 mmol/L menadion indicating that necrosis may occur. In situ detection of nuclear DNA fragmentation by TUNEL reaction revealed fragmented nuclear DNA in cells treated with 100-800 mumol/L menadion but not in cells treated with 1 mmol/L menadione.

Dynamic measurement of metabolic function in the rat liver: an application of reverse microdialysis

BACKGROUND

Traditional markers of liver function and microsomal activity tests require regular samplings and tissue removal. The microdialysis technique is a promising tool for pharmacokinetic study without the need for actually removing samples of those tissues and fluids. We verified the possibility of using reverse microdialysis for dynamic monitoring of hepatic metabolic function.

METHODS

Adult male Sprague-Dawley rats were used and anesthetized using pentobarbital sodium. Reverse microdialysis was done by implanting a microdialysis probe into the middle lobe of the liver; the probe was then perfused with a lidocaine-containing solution. Concentrations of lidocaine and its major metabolite, monoethylglycinexylidide (MEGX), were measured in the dialysate. Metabolic ability was assessed by dividing the MEGX production by lidocaine administration. Hepatic ischemia-reperfusion and liver cirrhosis models were used to verify its application in dynamic measurement of liver metabolic function.

RESULTS

The implantable microdialysis probe had stable contact with the liver tissue. In normal rats, 4.73 +/- 0.41% of the lidocaine was transformed to MEGX in 20 min. Only 16% of this value was preserved in cirrhotic animals. Hepatic ischemia for 20 min transiently depressed the MEGX formation and did not cause further injury after reperfusion.

CONCLUSION

We confirmed the ability of an implantable microdialysis probe to be in constant contact with the liver tissue and thus deliver a stable transmission of chemicals across a microdialysis membrane for a certain period of time. We also verified the feasibility of reverse microdialysis as a tool for the dynamic measurement of hepatic metabolic function.

The effect of Glu75 of staphylococcal nuclease on enzyme activity, protein stability and protein unfolding

Staphylococcal nuclease mutants, E57G and E75G, were generated. A comparison of the kinetic parameters both for mutants and wild-type protein shows that the Michaelis constants (Km) were almost identical for the wild-type protein and E57G mutant. An approximately 30-fold decrease in Km compared with the wild-type protein was observed for the E75G mutant. The turnover numbers for the enzyme (kcat) were higher with both the wild-type protein and the E57G mutant (3.88 +/- 0.21 x 103 s-1 and 3.71 +/- 0.28 x 103 s-1) than with the E75G mutant (3.04 +/- 0.02 x 102 s-1). The results of thermal denaturation with differential scanning microcalorimetry indicate that the excess calorimetric enthalpy of denaturations, DeltaHcal, was almost identical for the wild-type protein and E57G mutant (84.1 +/- 6.2 kcal.mol-1 and 79.3 +/- 7.1 kcal.mol-1, respectively). An approximately twofold decrease in DeltaHcal compared with the wild-type protein was observed for the E75G mutant (42.7 +/- 5.5 kcal.mol-1). These outcomes imply that Glu at position 75 plays a significant role in maintaining enzyme activity and protein stability. Further study of the unfolding of the wild-type protein and E75G mutant was conducted by using time-resolved fluorescence with a picosecond laser pulse. Two fluorescent lifetimes were found in the subnanosecond time range. The faster lifetime (tau2) did not generally vary with either pH or the concentration of guanidinium hydrochloride (GdmHCl) in the wild-type protein and the E75G mutant. The slow lifetime (tau1), however, did vary with these parameters and was faster as the protein is unfolded by either pH or GdmHCl denaturation. The midpoints of the transition for tau1 are pH 3.5 and 5.8 for the wild-type protein and E75G mutant, respectively, and the GdmHCl concentrations are 1.1 m and 0.6 m for the wild-type protein and E75G mutant, respectively. Parallel steady-state fluorescence measurements have also been carried out and the results are in general agreement with the time-resolved fluorescence experiments, indicating that Glu at position 75 plays an important role in protein unfolding.

An efficient, short synthesis and potent anti-hepatitis B viral activity of a novel ring-expanded purine nucleoside analogue containing a 5:7-fused, planar, aromatic, imidazo[4,5-e][1,3]diazepine ring system

An efficient, short synthesis of a ring-expanded nucleoside analogue containing a novel 5:7-fused, planar, and potentially aromatic imidazo[4,5-e][1,3]diazepine heterocyclic ring system is reported. The target compound, 6-amino-8-hydroxy-4H-1-beta-D- ribofuranosylimidazo[4,5-e][1,3]diazepin-4-one (2) was synthesized in a single step in > or = 90% yield by condensation of guanidine with either methyl 1-beta-D-ribofuranosylimidazole-4,5- dicarboxylate(1a) or its 2',3',5'-tri-O-benzoyl derivative (1b). Compound 2 showed potent anti-hepatitis B virus (anti-HBV) activity with an EC50 value of 0.17 microM in the transfected hepatoma cell line 2.2.15, and a low cellular toxicity with a CC50 value of 2.4 mM (TI > 14,000).

Study on binding of REEs with water-soluble polysaccharides in fern

The binding of rare earth elements (REEs) with water-soluble polysaccharides of nondeproteinization and deproteinization in the leaves of the fern Dicranopteris dichotoma was studied by molecular activation analysis (MAA). Two cold-water-soluble polysaccharides (extracted by 75% ethanol and 90% ethanol, respectively) and one hot-water-soluble polysaccharide (extracted by 90% ethanol) were separated using biochemical separation techniques. The eight rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb, and Lu) in these polysaccharides were determined by instrumental neutron activation analysis. Our new results showed that the REEs were bound firmly with the water-soluble polysaccharides in the plant, regardless of whether nondeproteinization or deproteinization was used. The molecular-weight (MW) measurement demonstrated that REEs were mainly bound with low-MW (10,000-20,000) polysaccharides.

Prostacyclin analogue (OP-2507) attenuates hepatic microcirculatory derangement, energy depletion, and lipid peroxidation in a rat model of reperfusion injury

BACKGROUND

Microcirculatory derangement, energy depletion, and lipid peroxidation are associated with the development of ischemia-reperfusion injury in the liver. This study investigated the effects of a prostacyclin analogue (OP-2507) on hepatic ischemia-reperfusion injury.

MATERIALS AND METHODS

Adult, male Sprague-Dawley rats were divided into four treatment groups: (1) sham-operated control (laparotomy only, no ischemia), N =6; (2) ischemia control (1 h ischemia, 2 h reperfusion), N = 6; (3) intravenous infusion with OP-2507 ([15-cis-14-propylcyclohexyl]-16, 17,18,19,20-pentanor-9-deoxy-9a,6-nitrilo-PGF, methyl ether; Ono Pharmaceutical Co, Ltd, Osaka, Japan) at a dose of 1 microg/kg/min plus ischemia (1 h ischemia, 2 h reperfusion), N = 6; and (4) intravenous infusion with OP-2507 at a dose of 0.1 microg/kg/min plus ischemia (1 h ischemia, 2 h reperfusion), N = 6. A laser-Doppler flowmeter and in vivo microscopy were used to investigate hepatic microcirculation. Tissue malondialdehyde (MDA) and adenosine triphosphate (ATP) levels were determined at the end of the experiment.

RESULTS

Compared with ischemia alone, OP-2507 significantly reduced the extent of microcirculatory and hemodynamic derangement following ischemia-reperfusion. The changes of mean systolic arterial pressure (MSAP) following ischemia-reperfusion showed biphasic alterations. OP-2507 at both doses significantly attenuated decreases in MSAP. OP-2507 lessened adherent leukocyte count and improved flow velocity in the sinusoids and postsinusoidal venules. OP-2507 at the dose of 1 microg/kg/min reduced MDA (1.04 +/- 0.27 micromol/g protein vs 2.64 +/- 0.59 micromol/g protein in the ischemia and reperfusion group) and increased ATP levels (2.03 +/- 0.17 micromol/g wet wt vs 0.73 +/- 0.21 micromol/g wet wt in the ischemia and reperfusion group), while OP-2507 at a smaller dose (0. 1 microg/kg/min) had lesser but significant effects on MDA and ATP alterations.

CONCLUSION

This study demonstrates that OP-2507 treatment of ischemia can ameliorate ischemia-reperfusion injury of the rat liver.

Microscopic observations of the different morphological changes caused by anti-bacterial peptides on Klebsiella pneumoniae and HL-60 leukemia cells

Natural anti-bacterial peptides cecropin B (CB) and its analogs cecropin B-1 (CB-1), cecropin B-2 (CB-2) and cecropin B-3 (CB-3) were prepared. The different characteristics of these peptides, with amphipathic/hydrophobic alpha-helices for CB, amphipathic/amphipathic alpha-helices for CB-1/CB-2, and hydrophobic/hydrophobic alpha-helices for CB-3, were used to study the morphological changes in the bacterial cell, Klebsiella pneumoniae and the leukemia cancer cell, HL-60, by scanning and transmission electron microscopies. The natural and analog peptides have comparable secondary structures as shown by circular dichroism measurements. This indicates that the potency of the peptides on cell membranes is dependent of the helical characteristics rather than the helical strength. The microscopic results show that the morphological changes of the cells treated with CB are distinguishably different from those treated with CB-1/CB-2, which are designed to have enhanced anti-cancer properties by having an extra amphipathic alpha-helix. The morphological differences may be due to their different modes of action on the cell membranes resulting in the different potencies with lower lethal concentration and higher concentration of 50% inhibition (IC50) of CB on bacterium and cancer cell, respectively, as compared with CB-1/:CB-2 (Chen et al. 1997. Biochim. Biophys. Acta 1336, 171-179). In contrast, CB-3 has little effect on either the bacterium or the cancer cell. These results provide microscopic evidence that different killing pathways are involved with the peptides.

Enhancement of the cytolytic effect of anti-bacterial cecropin by the microvilli of cancer cells

A comparison between IC50s of cecropin B on tumor cells such as KG-1 leukemia and Ags stomach carcinoma and non-tumor cells like fibroblasts and red blood cells was conducted. The IC50s of cecropin B for KG-1 leukemia and Ags carcinoma cells were 20.8 +/- 2.3 microM (MTT) and 18.9 +/- 3.3 microM (trypan blue) and 16.0 +/- 3.5 microM (MTT) & 15.3 +/- 3.7 microM (trypan blue), respectively. The IC50 of cecropin B for 3T6 fibroblast cells was 92.0 +/- 9.1 microM by MTT assay and the HE50 of cecropin B for human red blood cells was 180.0 +/- 20.1 microM at OD414nm. The cytolysis induced by cecropin peptides was more effective for the cancer cells than for the normal cells. Based on the observations from scanning electron microscopy, this may mainly due to the cancer cells having a high population of the irregular microvilli on the cell surface. Since peptides bound to the cell membrane are non-specific, the attraction of peptides by microvilli may be one of the main driving forces before the lysis in membrane bilayers can be efficiently initiated.

Serum vitamin A level in breast cancer patients

Vitamin A or its synthetic analogues are potent in controlling cell differentiation and in preventing epithelial cancer in experimental animals. Although some community-based studies have found that high serum retinol levels in prediagnostic sera were associated with reduced risk for cancer, other reports in humans have not confirmed this finding. This study is to evaluate the preoperative serum vitamin A level in breast cancer patients in Taiwan. The serum specimens were collected from 106 female cases of breast cancer (aged 30 to 70 years), 32 female cases of benign breast disease (aged 29 to 57 years), and 40 healthy females (aged 22 to 52 years). The serum vitamin A levels were measured by colorimetic analysis. The results showed the mean value of the vitamin A level was 140.4 +/- 65.7 micrograms/dl in the breast cancer group comparing to 145.2 +/- 44.2 micrograms/dl in the benign breast disease group, 144.0 +/- 30.0 micrograms/dl in the control group (P > 0.05). The characteristics of the breast cancer group were analyzed and they revealed that serum vitamin A levels did not bear statistically significant differences in age, duration, steroid receptor, tumor size and menopausal state. (P > 0.05) In conclusion, the serum vitamin A levels were not decreased in early breast cancer patients. The serum vitamin A levels were significantly decreased in the metastatic breast cancer group, especially in liver metastatic women. (P < 0.05). Postoperative vitamin A supplement may have potential benefit to metastatic breast cancer patients.

Clinical analysis of inflammatory masses of the pancreatic head region

BACKGROUND/AIMS

Inflammatory masses of the pancreatic head are a dilemma for surgeons, especially when the differences between these lesions and pancreatic head carcinoma are not so clear. The surgical management of these inflammatory benign lesions is also a topic with conflicting opinions. A clinical analysis was performed in an attempt to differentiate between these lesions and malignancy. The results of our observatory strategy of these lesions are also presented.

METHODOLOGY

From 1992 to 1994, 73 patients with ultrasonographically (US) or computed tomographically (CT) heterogenous pancreatic head lesions were diagnosed at the Department of Surgery, Chang Gung Memorial Hospital, Taipei, Taiwan. Forty-nine of these lesions were neoplastic (Group I), but the remaining 24 patients had inflammatory non-neoplastic lesions (pancreatic inflammatory masses, IPM, Group II), which were diagnosed during laparotomy by core needle biopsy. Surgery and outcome were reviewed. Ten of the 24 patients in group II received biopsy only, and the remaining 14 patients received bypass procedures. At follow-up of at least 16 months of the surviving patients (n=21), only 9.5% were with residual lesions. All cases in group II revealed shrinkage of masses. We focused on the clinical features, hematology, biochemistry, image study, serum CEA and CA 19-9, and compared these variances between the 2 groups.

RESULTS

Three clinical features were statistically different between groups I and II: mean age at presentation of disease (group I vs II = 53.3 vs 65.1), the tendency of a past history of alcoholism (Group II), and presence of abdominal pain (Group II). Group II also showed a higher level of serum alkaline phosphatase and a lower level of total bilirubin as well as a lower level of CA19-9. These inflammatory masses could not be distinguished from the true neoplasms pre-operatively on endoscopic appearance, US, or CT.

CONCLUSIONS

Pre-operative differentiation between these pancreatic lesions may be difficult but laparotomy and core needle biopsy remain safe and reliable procedures. Our short-term follow-up justified the bypass surgery and that observatory strategy is enough for those patients with pancreatic head inflammatory masses.