BAFF-neutralizing interaction of belimumab related to its therapeutic efficacy for treating systemic lupus erythematosus

BAFF, a member of the TNF superfamily, has been recognized as a good target for autoimmune diseases. Belimumab, an anti-BAFF monoclonal antibody, was approved by the FDA for use in treating systemic lupus erythematosus. However, the molecular basis of BAFF neutralization by belimumab remains unclear. Here our crystal structure of the BAFF-belimumab Fab complex shows the precise epitope and the BAFF-neutralizing mechanism of belimumab, and demonstrates that the therapeutic activity of belimumab involves not only antagonizing the BAFF-receptor interaction, but also disrupting the formation of the more active BAFF 60-mer to favor the induction of the less active BAFF trimer through interaction with the flap region of BAFF. In addition, the belimumab HCDR3 loop mimics the DxL(V/L) motif of BAFF receptors, thereby binding to BAFF in a similar manner as endogenous BAFF receptors. Our data thus provides insights for the design of new drugs targeting BAFF for the treatment of autoimmune diseases.

Structural Biology of the TNFα Antagonists Used in the Treatment of Rheumatoid Arthritis

The binding of the tumor necrosis factor α (TNFα) to its cognate receptor initiates many immune and inflammatory processes. The drugs, etanercept (Enbrel^®), infliximab (Remicade^®), adalimumab (Humira^®), certolizumab-pegol (Cimzia^®), and golimumab (Simponi^®), are anti-TNFα agents. These drugs block TNFα from interacting with its receptors and have enabled the development of breakthrough therapies for the treatment of several autoimmune inflammatory diseases, including rheumatoid arthritis, Crohn's disease, and psoriatic arthritis. In this review, we describe the latest works on the structural characterization of TNFα-TNFα antagonist interactions related to their therapeutic efficacy at the atomic level. A comprehensive comparison of the interactions of the TNFα blockers would provide a better understanding of the molecular mechanisms by which they neutralize TNFα. In addition, an enhanced understanding of the higher order complex structures and quinary structures of the TNFα antagonists can support the development of better biologics with the improved pharmacokinetic properties. Accumulation of these structural studies can provide a basis for the improvement of therapeutic agents against TNFα for the treatment of rheumatoid arthritis and other autoimmune inflammatory diseases in which TNFα plays an important role in pathogenesis.

Evaluation of the Cross-reactivity of Antidrug Antibodies to CT-P13 and Infliximab Reference Product (Remicade): An Analysis Using Immunoassays Tagged with Both Agents

Background

During two pivotal clinical trials of the infliximab biosimilar CT-P13 (PLANETAS and PLANETRA), antidrug antibodies (ADAs) and neutralising antibodies (NAbs) were detected in the sera of patients treated with CT-P13 and the reference product (RP; Remicade).

Objective

The aim was to assess the comparability of Remicade- and CT-P13-tagged immunoassays for the detection of ADAs and NAbs using data from these trials, in order to determine the cross-reactivity of CT-P13 and RP ADAs.

Methods

Sera from patients with rheumatoid arthritis and ankylosing spondylitis were analysed using an electrochemiluminescence (ECL) bridging assay or Gyros immunoassay, tagged with Remicade or CT-P13 at screening, weeks 14, 30 and 54, and the end of study visit. NAb titre was compared at screening and weeks 14 and 30. The proportion of cross-reactive samples was determined and an inter-rater agreement analysis performed to assess the concordance of results between assays.

Results

In PLANETAS, 93.1% (94/101) of RP ADA-positive samples and 93.0% (93/100) of RP NAb-positive samples cross-reacted with CT-P13; 99.0% (103/104) of CT-P13 ADA-positive and 98.0% (98/100) of CT-P13 NAb-positive samples cross-reacted with the RP. In PLANETRA, 94.7% (426/450) of RP ADA-positive samples and 94.3% (415/440) of RP NAb-positive samples cross-reacted with CT-P13, and 96.6% (458/474) of CT-P13 ADA-positive and 96.4% (452/469) of CT-P13 NAb-positive samples cross-reacted with the RP. In both studies, there was strong agreement in outcome between assays at all post-screening time points (PLANETAS: Cohen’s κ 0.89–0.98 for ADA, 0.86–0.98 for NAb; PLANETRA: 0.92–0.94 for both ADA and NAb, all p < 0.001). Significant concordance between assays was observed for NAb titre at weeks 14 and 30 (PLANETAS: Spearman’s ρ 0.73 and 0.74, respectively; PLANETRA: 0.61 and 0.72, respectively; all p < 0.001).

Conclusions

This study has demonstrated that ADAs and NAbs against CT-P13 and RP are cross-reactive, indicating that CT-P13 and RP share immunodominant epitopes.

Electronic supplementary material

The online version of this article (doi:10.1007/s40259-017-0219-4) contains supplementary material, which is available to authorized users.

Molecular Basis for the Neutralization of Tumor Necrosis Factor α by Certolizumab Pegol in the Treatment of Inflammatory Autoimmune Diseases

Monoclonal antibodies against TNFα, including infliximab, adalimumab, golimumab, and certolizumab pegol, are widely used for the treatment of the inflammatory diseases such as rheumatoid arthritis and inflammatory bowel disease. Recently, the crystal structures of TNFα, in complex with the Fab fragments of infliximab and adalimumab, have revealed the molecular mechanisms of these antibody drugs. Here, we report the crystal structure of TNFα in complex with the Fab fragment of certolizumab pegol to clarify the precise antigen-antibody interactions and the structural basis for the neutralization of TNFα by this therapeutic antibody. The structural analysis and the mutagenesis study revealed that the epitope is limited to a single protomer of the TNFα trimer. Additionally, the DE loop and the GH loop of TNFα play critical roles in the interaction with certolizumab, suggesting that this drug exerts its effects by partially occupying the receptor binding site of TNFα. In addition, a conformational change of the DE loop was induced by certolizumab binding, thereby interrupting the TNFα-receptor interaction. A comprehensive comparison of the interactions of TNFα blockers with TNFα revealed the epitope diversity on the surface of TNFα, providing a better understanding of the molecular mechanism of TNFα blockers. The accumulation of these structural studies can provide a basis for the improvement of therapeutic antibodies against TNFα.

Structure of the catalytic phosphatase domain of MTMR8: implications for dimerization, membrane association and reversible oxidation

Myotubularin-related proteins are a large family of phosphoinositide phosphatases; their activity, stability and subcellular localization are regulated by dimeric interactions with other members of the family. Here, the crystal structure of the phosphatase domain of MTMR8 is reported. Conformational deviation of the two loops that mediate interaction with the PH-GRAM domain suggests that the PH-GRAM domain interacts differently with the phosphatase domain of each MTMR member. The protein exists as a dimer with twofold symmetry, providing insight into a novel mode of dimerization mediated by the phosphatase domain. Structural comparison and mutation studies suggest that Lys255 of MTMR8 interacts with the substrate diacylglycerol moiety, similar to Lys333 of MTMR2, although the positions of these residues are different. The catalytic activity of the MTMR8 phosphatase domain is inhibited by oxidation and is reversibly reactivated by reduction, suggesting the presence of an oxidation-protective intermediate other than a disulfide bond owing to the absence of a cysteine within a disulfide-bond distance from Cys338.

Expression, purification, crystallization and preliminary crystallographic analysis of human myotubularin-related protein 3

Myotubularin-related proteins are a large family of phosphatases that have the catalytic activity of dephosphorylating the phospholipid molecules phosphatidylinositol 3-phosphate and phosphatidylinositol 3,5-bisphosphate. Each of the 14 family members contains a phosphatase catalytic domain, which is inactive in six family members owing to amino-acid changes in a key motif for the activity. All of the members also bear PH-GRAM domains, which have low homologies between them and have roles that are not yet clear. Here, the cloning, expression, purification and crystallization of human myotubularin-related protein 3 encompassing the PH-GRAM and the phosphatase catalytic domain are reported. Preliminary X-ray crystallographic analysis shows that the crystals diffracted to 3.30 Å resolution at a synchrotron X-ray source. The crystals belonged to space group C2, with unit-cell parameters a = 323.3, b = 263.3, c = 149.4 Å, β = 109.7°.

Crystallization and preliminary X-ray crystallographic analysis of the PH-GRAM domain of human MTMR4

Phosphoinositide lipid molecules play critical roles in intracellular signalling pathways and are regulated by phospholipases, lipid kinases and phosphatases. In particular, phosphatidylinositol 3-phosphate and phosphatidylinositol 3,5-bisphosphate are related to endosomal trafficking events through the recruitment of effector proteins and are involved in the degradation step of autophagy. Myotubularin-related proteins (MTMRs) are a large family of phosphatases that catalyze the dephosphorylation of phosphatidylinositol 3-phosphate and phosphatidylinositol 3,5-bisphosphate at the D3 position, thereby regulating cellular phosphoinositide levels. In this study, the PH-GRAM domain of human MTMR4 was cloned, overexpressed in Escherichia coli, purified and crystallized by the vapour-diffusion method. The crystals diffracted to 3.20 Å resolution at a synchrotron beamline and belonged to either space group P61 or P65, with unit-cell parameters a = b = 109.10, c = 238.97 Å.

Attenuated benzodiazepine-sensitive tonic GABAA currents of supraoptic magnocellular neuroendocrine cells in 24-h water-deprived rats

In supraoptic nucleus (SON) magnocellular neurosecretory cells (MNCs), γ-GABA, via activation of GABAA receptors (GABAA Rs), mediates persistent tonic inhibitory currents (Itonic ), as well as conventional inhibitory postsynaptic currents (IPSCs, Iphasic ). In the present study, we examined the functional significance of Itonic in SON MNCs challenged by 24-h water deprivation (24WD). Although the main characteristics of spontaneous IPSCs were similar in 24WD compared to euhydrated (EU) rats, Itonic , measured by bicuculline (BIC)-induced Iholding shifts, was significantly smaller in 24WD compared to EU rats (P < 0.05). Propofol and diazepam prolonged IPSC decay time to a similar extent in both groups but induced less Itonic in 24WD compared to EU rats, suggesting a selective decrease in GABAA receptors mediating Itonic over Iphasic in 24WD rats. THIP (4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol), a preferential δ subunit agonist, and L-655,708, a GABAA receptor α5 subunit selective imidazobenzodiazepine, caused a significantly smaller inward and outward shift in Iholding , respectively, in 24WD compared to EU rats (P < 0.05 in both cases), suggesting an overall decrease in the α5 subunit-containing GABAA Rs and the δ subunit-containing receptors mediating Itonic in 24WD animals. Consistent with a decrease in 24WD Itonic , bath application of GABA induced significantly less inhibition of the neuronal firing activity in 24WD compared to EU SON MNCs (P < 0.05). Taken together, the results of the present study indicate a selective decrease in GABAA Rs functions mediating Itonic as opposed to those mediating Iphasic in SON MNCs, demonstrating the functional significance of Itonic with respect to increasing neuronal excitability and hormone secretion in 24WD rats.

RAF kinase inhibitor-independent constitutive activation of Yes-associated protein 1 promotes tumor progression in thyroid cancer

The transcription coactivator Yes-associated protein 1 (YAP1) is regulated by the Hippo tumor suppressor pathway. However, the role of YAP1 in thyroid cancer, which is frequently associated with the BRAF^V600E mutation, remains unknown. This study aimed to investigate the role of YAP1 in thyroid cancer. YAP1 was overexpressed in papillary (PTC) and anaplastic thyroid cancer, and nuclear YAP1 was more frequently detected in BRAF^V600E (+) PTC. In the thyroid cancer cell lines TPC-1 and HTH7, which do not have the BRAF^V600E mutation, YAP1 was cytosolic and inactive at high cell densities. In contrast, YAP1 was retained in the nucleus and its target genes were expressed in the thyroid cancer cells 8505C and K1, which harbor the BRAF^V600E mutation, regardless of cell density. Furthermore, the nuclear activation of YAP1 in 8505C was not inhibited by RAF or MEK inhibitor. In vitro experiments, YAP1 silencing or overexpression affected migratory capacities of 8505C and TPC-1 cells. YAP1 knockdown resulted in marked decrease of tumor volume, invasion and distant metastasis in orthotopic tumor xenograft mouse models using the 8505C thyroid cancer cell line. Taken together, YAP1 is involved in the tumor progression of thyroid cancer and YAP1-mediated effects might not be affected by the currently used RAF kinase inhibitors.

Angle-dependent carrier transmission in graphene p-n junctions

Angle-dependent carrier transmission probability in graphene p-n junctions is investigated. Using electrostatic doping from buried gates, p-n junctions are formed along graphene channels that are patterned to form different angles with the junction. A peak in the junction resistance is observed, which becomes pronounced with angle. This angular dependence is observed for junctions made on both exfoliated and CVD-grown graphene and is consistent with the theoretically predicted dependence of transmission probability on incidence angle.

Metal removal from wastewater by bacterial sorption: kinetics and competition studies

Biosorption has distinct advantages such as high efficiency and cost-effectiveness for removal of metal ions from wastewater. However, most studies of bacterial biosorption have focused on the removal of a single metal ion from aqueous solutions, even though natural water and wastewater rarely contain only one kind of heavy metal. This study investigated competitive biosorption of Co2+, Ni2+ and Cr3+ in different combinations at various concentrations under conditions of co-existence in a synthetic wastewater system utilizing the gram-negative bacterium Pseudomonas aeruginosa. In a binary system with Co2+ and Ni2+, the presence of the same concentration of dissolved Ni2+ led to a significant decrease in the amount of Co2+ adsorbed onto cells when compared with a single Co2+ system in which Ni2+ was absent. This result is most likely due to the similar competitive affinity of these equivalent cations for sorption sites located on the cells of the bacterium. However, the presence of Cr3+ with either Co2+ or Ni2+ led to a strong reduction in the uptake of each of these bivalent ions by cells, whereas Cr3+ adsorption was unhindered. Cr3+ also significantly inhibited the adsorption of both Co2+ and Ni2+ onto cells in a ternary system involving Co2+-Ni2+-Cr3+, with the order of preferential metal uptake being Cr3+ > Co2+ approximately Ni2+. Removal efficiency of the heavy metals reached 100 % at low concentrations ([Cr3+]=[Co2+]=[Ni2+=20 microM) in a multi-metal system. The results of this study indicate that pre-determination of co-existing heavy metals in wastewater and examination of their competition for the sorption sites of biosorbents are required for the efficient removal of inorganic toxicants utilizing biosorption processes.

Effects of intracoronary calcium chloride on regional oxygen balance and mechanical function in normal and stunned myocardium in dogs

BACKGROUND

Brief myocardial ischaemia has been demonstrated to result in mechanical and coronary endothelial dysfunction, in which calcium may play a role. We examined whether the mechanical and vascular responses to calcium are altered in postischaemic, reperfused myocardium.

METHODS

Regional myocardial oxygen consumption (MVO2), mechanical function and coronary blood flow (CBF) in response to calcium chloride (0.10, 0.25, 0.50 and 0.75 mg ml(-1) of CBF) directly infused into the left anterior descending (LAD) artery were determined before (normal) and 30 min after a 15-min-period of LAD occlusion (stunned) in an open-chest canine model. Percentage segment shortening (%SS) and percentage postsystolic shortening (%PSS) in the LAD territory were determined using ultrasonic crystals and CBF using a Doppler transducer. Myocardial extraction of oxygen (EO2) and lactate (Elac) was calculated.

RESULTS

The infusion of calcium chloride resulted in dose-dependent increases in %SS and MVO2 but did not affect %PSS in normal myocardium. These changes were accompanied by parallel increases in CBF, resulting in no change in EO2. In stunned myocardium, the responses to calcium chloride were not significantly altered, with the exception of a reduction in %PSS. However, ischaemia and reperfusion itself significantly reduced %SS and Elac and increased %PSS.

CONCLUSIONS

These data suggest that calcium chloride improves regional systolic and diastolic function both in normal and stunned myocardium. Calcium chloride is unlikely to cause direct coronary vasoconstriction or to deteriorate regional mechanical function in postischaemic myocardium.

Hemodynamic and catecholamine responses to laryngoscopy and tracheal intubation in patients with complete spinal cord injuries

BACKGROUND

Endotracheal intubation in patients undergoing general anesthesia often causes hypertension and tachycardia, which may be altered when the efferent sympathetic fiber to the cardiovascular system is interrupted. The aim of the current study was to investigate the effects of different levels of spinal cord injury on the cardiovascular responses to intubation.

METHODS

Fifty-four patients with traumatic complete cord injuries requiring tracheal intubation were grouped into quadriplegics (above C7; n = 22), high paraplegics (T1-T4, n = 8), and low paraplegics (below T5, n = 24) according to the level of injury. Twenty patients without spinal injury served as controls. Arterial pressure, heart rate, and rhythm were recorded at intervals for up to 5 min after intubation. Plasma concentrations of catecholamines were also measured.

RESULTS

The intubation increased the systolic blood pressure similarly in control, high-paraplegic, and low-paraplegic groups (P < 0.05), whereas it did not alter the blood pressure in the quadriplegic group. Heart rate was significantly increased in all groups; however, the magnitude was more pronounced in the high-paraplegic group (67%) than in the control (38%) and quadriplegic (33%) groups. Plasma concentrations of norepinephrine were significantly increased after intubation in all groups; however, values were lower in the quadriplegic group and higher in the low-paraplegic group compared with those in the control group. Incidence of arrhythmias did not differ among groups.

CONCLUSIONS

The cardiovascular and plasma catecholamine changes associated with endotracheal intubation may differ according to the affected level in patients with complete spinal cord injuries.

Increased expression of atrial natriuretic peptide in ureteral obstructed kidneys in rats

OBJECTIVES

Whether the natriuresis in the previously ureteral obstructed kidney may be related to an altered regulation of local atrial natriuretic peptide (ANP) was investigated.

MATERIALS AND METHODS

Male Sprague-Dawley rats were unilaterally obstructed of the left ureters for 48 hours. The left and right ureters were separately cannulated to collect urine samples. In some rats, both kidneys were removed without releasing the obstruction. Control rats were treated the same except that no ureteral obstruction was made. The mRNA expression of ANP and natriuretic peptide receptor (NPR)-A was determined in the kidney by reverse transcription-polymerase chain reaction. The guanylyl cyclase activity was measured by the amount of cGMP generated in response to ANP. Plasma levels of ANP were measured by radioimmunoassay.

RESULTS

The ureteral obstruction did not significantly affect the plasma ANP levels. In the obstructed kidney, the creatinine clearance was decreased, while the fractional excretion of sodium increased. The expression of ANP mRNA was increased in the obstructed kidney. The NPR-A mRNA expression was not altered in the glomerulus, but was decreased in the papilla of the obstructed kidney. Nor was the guanylyl cyclase activity in the glomerulus altered. Although the guanylyl cyclase activity in the papilla was significantly decreased in the obstructed kidney, it was rapidly resumed upon releasing the obstruction.

CONCLUSIONS

An increased local expression of ANP may, at least in part, account for the natriuresis in the previously ureteral obstructed kidney.

Two imported cases of cutaneous larva migrans

Cutaneous larva migrans (CLM) is a rare serpiginous cutaneous eruption caused by accidental penetration and migration in the skin with infective larvae of nematode that normally do not have the human as their host. Although CLM has a worldwide distribution, the infection is most frequent in warmer climates. More recently, they have been increasingly imported from the tropics or subtropics by travelers. We experienced two patients who had pruritic serpiginous linear eruption in their skin for a few weeks after traveling to the endemic areas (Brazil and Thailand, respectively). After the treatment with albendazole, the skin lesions resolved with post-inflammatory hyperpigmentation. We report herein two cases of cutaneous larva migrans successfully treated with albendazole.

Enhanced gene expression of renin-angiotensin system, TGF-beta1, endothelin-1 and nitric oxide synthase in right-ventricular hypertrophy

It has been suggested that various vasoactive substances and growth factors are involved in left-ventricular myocardial hypertrophy and failure. However, limited data are available on the role of humoral factors involved in right-ventricular (RV) hypertrophy. To examine implications of humoral factors involved in the development of RV hypertrophy, altered mRNA expressions of the renin-angiotensin system (RAS), transforming growth factor (TGF)- beta1, endothelin-1 and nitric oxide synthase (NOS) were investigated in monocrotaline (MCT)-induced pulmonary hypertensive rats. Male Sprague-Dawley rats were treated with MCT (60 mg x kg(-1), s.c.) to induce a selective RV hypertrophy. Three or 6 weeks later, the heart was removed to determine the tissue gene expressions in the right and left ventricles (LV) by reverse transcription-polymerase chain reaction due to the relatively low mRNA expression levels of the RAS components in the ventricle (n= 6 in each group). MCT-treated rats showed a selective RV hypertrophy at weeks 3 and 6 of MCT treatment (the ratios of RV/body weight were 1.5- and 2.2-fold higher than the controls, respectively). Levels of renin and angiotensinogen mRNAs in the hypertrophied RV were significantly increased at both weeks 3 and 6 of MCT treatment. The angiotensin-converting enzyme mRNA level also increased approximately 2-fold at week 3. In contrast, RAS component mRNAs in the LV were not significantly altered by MCT treatment, except for a 1.8-fold increase of angiotensinogen mRNA at week 3. The expression of Ang II receptors, either AT1A or AT1B, was not significantly altered by MCT treatment. Furthermore, MCT treatment significantly increased TGF- beta1 mRNA levels in the RV at weeks 3 and 6, while it did not significantly affect them in the LV. Endothelin-1 mRNA expression was significantly higher in the RV at week 3, but was normalized at week 6 of MCT treatment. The gene expression of the endothelial constitutive isoform of NOS was increased in the RV at weeks 3 and 6, but not in the LV. Elevated gene expression of local RAS, along with TGF- beta1 and endothelin-1 in the present study may contribute to the development of RV hypertrophy. On the contrary, an enhanced ecNOS expression may be a mechanism counteracting the hypertrophy.

Increased vascular endothelin-1 gene expression with unaltered nitric oxide synthase levels in fructose-induced hypertensive rats

The present study aimed to investigate whether altered expression levels of endothelin-1 (ET-1) and nitric oxide synthase (NOS) are related to the development of insulin-resistant hypertension. Male Sprague-Dawley rats were fed a fructose-rich diet for 5 weeks. Systolic blood pressure significantly increased in fructose-fed rats. While serum free fatty acid (FFA) and plasma nitrite/nitrate (NOx) levels did not significantly differ between the fructose-fed and control groups, plasma insulin and serum triglyceride (TG) concentrations significantly increased in the former. ET-1 mRNA expression in the aorta increased to 195% in fructose-fed rats. Neither the protein expression of constitutive NOS (cNOS) nor that of inducible NOS (iNOS) were significantly affected by fructose feeding. However, NOx levels in the aorta were significantly increased. These results indicate that an increased expression of vascular ET-1 may be causally related to the development of hypertension in fructose-fed rats. However, an altered role of the vascular nitric oxide (NO) pathway may not be primarily involved in the development of fructose-induced hypertension.

Effects of prednisolone on eosinophils, IL-5, eosinophil cationic protein, EG2+ eosinophils, and nitric oxide metabolites in the sputum of patients with exacerbated asthma

Corticosteroids are considered to be one of the most effective medicine for asthma by suppressing airway inflammation. This study was carried out to investigate the effects of prednisolone in the sputum of exacerbated asthmatics. Clinical severity, cell differentials, levels of interleukin (IL)-5, eosinophil cationic protein (ECP), EG2+ eosinophils, and nitric oxide (NO) metabolites were measured. Sputum was examined 2 weeks apart in 13 exacerbated asthmatics before and after prednisolone treatment, and once in 12 stable asthmatics. We used a sandwich ELISA for IL-5, fluoroimmunoassay for ECP, immunohistochemical staining for EG2+ eosinophils, a NO metabolites assay using modified Griess reaction. Exacerbated asthmatics, in comparison with stable asthmatics, had significantly higher proportion of eosinophils, higher level of ECP, higher percentage of EG2+ eosinophils, and NO metabolites. Exacerbated asthmatics after treatment with prednisolone had reduced the proportions of eosinophils, reduced level of IL-5, ECP and percentage of EG2+ eosinophils. FEV1 was correlated with the proportion of eosinophils, ECP, and IL-5 respectively. These findings suggest that prednisolone is considered to be effective medicine for asthma by suppressing eosinophil activation through IL-5.

Immunohistochemical analysis of Bcl-2, Bax, Bcl-X, and Mcl-1 expression in pancreatic cancers

Expression of several members of the Bcl-2 family proteins was investigated by means of both immunohistochemical analysis in 30 invasive ductal adenocarcinomas and 23 intraductal papillary-mucinous tumors (IPMTs) and immunoblot analysis in 6 cancer tissues and 7 pancreatic cancer cell lines. We found that Bcl-2 was expressed in 23%, Bax in 53%, Bcl-X in 90%, and Mcl-1 in 90% of the invasive ductal adenocarcinomas. In intraductal papillary-mucinous adenocarcinomas, the expression rate of Bax was 44% and those of Bcl-XL and Mcl-1 were 88%; these values were higher than those for intraductal papillary-mucinous adenomas. Immunoblot analysis identified Bcl-XL as the predominant form of the Bcl-X protein in both pancreatic cancer tissues and cell lines, and demonstrated that both Bcl-XL and Mcl-1 protein levels were uniformly high in all cell lines. These results suggest that an imbalance between antiapoptosis proteins (such as Bcl-2, Bcl-XL, and Mcl-1) and proapoptotic proteins (such as Bax and Bcl-Xs) is involved in the distinctive biologic features of adenocarcinomas of the pancreas. Furthermore, predominantly high expressions of Bcl-XL and Mcl-1 in intraductal papillary-mucinous adenocarcinomas might be involved in the carcinogenesis in IPMT of the pancreas.

Diminished adenylate cyclase activity and aquaporin 2 expression in acute renal failure rats

BACKGROUND

The present study was aimed at investigating the changes of aquaporin 2 (AQP2) expression and its underlying mechanisms in ischemic acute renal failure (ARF).

METHODS

ARF was induced by clamping the both renal arteries for 60 minutes in rats. Two or seven days later, AQP2 expression and trafficking were determined in the kidney by Western blot analysis and immunohistochemistry. The activity of adenylate cyclase was also measured.

RESULTS

The urinary flow rates in ARF-2 and ARF-7 day were significantly increased in association with decreases of urine osmolality. While there was decreased expression of AQP2 in the cortex, outer medulla, and inner medulla in ARF, it was most pronounced in the outer medulla. The AQP2 expression was reduced in the apical membrane-enriched fraction as well the subapical vesicle-enriched fraction in ARF; however, the degree was greater in the former than in the latter. Immunohistochemical study also showed a markedly decreased expression of AQP2 in the collecting duct in ARF. cAMP generation in response to arginine vasopressin (AVP) in the kidney was attenuated in ARF, most prominently in the outer medulla. cAMP generation in the outer medulla in response to forskolin was not affected, but sodium fluoride was significantly blunted in ARF.

CONCLUSIONS

The AVP-stimulated adenylate cyclase activity is impaired in ARF, secondary to a defect at the level of the G protein. The expression of AQP2 was reduced as a consequence, which may in part account for urinary concentration defect in ARF.

Changes of glucose transporters in the cerebral adaptation to hypoglycemia

Repeated hypoglycemia increases the glycemic thresholds of responses of counterregulatory hormones and of symptoms to subsequent hypoglycemia. This may in part be due to cerebral adaptation to hypoglycemia, which involves glucose transporter-1 (GLUT1) and glucose transporter-3 (GLUT3). To investigate the role of brain GLUT1 and GLUT3 in cerebral adaptation to chronic hypoglycemia, GLUT1 and GLUT3 mRNA and protein expressions were determined in rat brain using RT-PCR and Western blot analyses after 4- and 8-day hypoglycemic insults. Hypoglycemia was induced in rats by twice daily subcutaneous injection of intermediate-acting insulin with dosage adjustment according to the blood glucose levels. Target level of hypoglycemia (< 2.5 mmol/l) was achieved at least once a day in all rats included. Control rats received saline injections. Blood glucose levels during the 4 and 8 days of insulin treatment were 2.18 +/- 0.12 and 2.68 +/- 0.07 mmol/l, respectively. Following the 4 and 8 days of hypoglycemia, GLUT1 mRNA levels did not significantly change. GLUT3 mRNA expressions after the 4 days of hypoglycemia increased by 36.9 +/- 9.4% compared with that in control rats (P = 0.031), but after the 8 days of hypoglycemia, did not change. On Western blot analysis of total particulate rat brain membrane, amount of 55-kDa isoform of GLUT1 protein did not change after 4- and 8-day hypoglycemia (88.1 +/- 4.9% of control, P = 0.240; 92.1 +/- 1.4% of control, P = 0.096, respectively). In contrast, the expression of GLUT3 protein in the 4-day hypoglycemic rats increased by 51.4 +/- 8.4% compared with that in control rats (P = 0.004). After the 8 days of hypoglycemia, the expression also tended to increase by 44.9 +/- 14.4% (P = 0.119). There was an inverse correlation between the amount of GLUT3 protein expression and mean blood glucose levels in 4-day hypoglycemic and control rats (r = -0.886, P = 0.019). These data suggest that GLUT3 isoform plays a role in the cerebral adaptation to chronic hypoglycemia.

Immunohistochemical analysis of cyclooxygenase-2 expression in pancreatic tumors

BACKGROUND

A considerable amount of evidence collected from several experimental systems and clinical studies with nonsteroidal Anti-inflammatory drugs (NSAIDs) indicates that Cox-2 may play a major role in colorectal tumorigenesis, but little information about Cox-2 expression in pancreatic tumors is available. In this study, we investigated Cox-2 expression by means of both immunohistochemical analysis and immunoblot analysis in pancreatic tumors.

METHODS

Fifty invasive ductal adenocarcinomas and 26 intraductal papillary-mucinous tumors (IPMTs) were used for immunohistochemical analysis, and five pancreatic cancer tissues and five pancreatic cancer cell lines for immunoblot analysis.

RESULTS

Cox-2 was expressed in 72% of the invasive ductal adenocarcinomas, 31% of intraductal papillary-mucinous adenocarcinomas, and none of intraductal papillary-mucinous adenomas. The expression rate of Cox-2 in intraductal papillary-mucinous adenocarcinomas was significantly higher than that in intraductal papillary-mucinous adenomas, and that in invasive ductal adenocarcinomas was significantly higher than that in intraductal papillary-mucinous carcinomas. However, there was no significant correlation between Cox-2 expression and the prognosis and clinicopathological factors. Immunoblot analysis identified Cox-2 in all of pancreatic cancer tissues and 60% of cell lines.

CONCLUSION

The biological role of cyclooxygenase-2 (Cox-2) in carcinoma cells should be investigated with reference to the cancer progression of the pancreas.

Role of Bcl-2 family proteins (Bax, Bcl-2 and Bcl-X) on cellular susceptibility to radiation in pancreatic cancer cells

The aim of this study was to examine Bax, Bcl-2 and Bcl-XL proteins in human pancreatic cancer cell lines and to clarify the mechanism of radiation resistance. PANC-1 and AsPC-1 pancreatic cell lines were used, both having mutated p53. Radioresistant PANC-1/Rad cells and AsPC-1/Rad cells were obtained by repeated 5 Gy irradiation of PANC-1 cells and AsPC-1 cells, respectively. Radiation was found to inhibit the growth of PANC-1 cells and AsPC-1 cells. After exposure to radiation, detached cells were subjected to FITC-TUNEL staining to calcualte the ratio of apoptosis. TUNEL positive ratios increased dose-dependently in both cell lines. Western blotting showed that the basal level of the Bax/Bcl-2 ratio reflected the radiosensitivity of these cell lines, and Bax expression was obviously upregulated after irradiation in the presence of mutated p53, but Bcl-2 expression remained almost constant. Both PANC-1/Rad and AsPC-1/Rad cells had greater Bcl-XL expression than the parental cells, and the basal level of the Bax/Bcl-2 ratio was no longer predictive of radiosensitivity. Upregulated expression of Bax protein after irradiation was not related to induction of apoptosis in these cells, suggesting that overexpression of Bcl-XL and functional reconstruction of Bcl-2 family proteins are important factors in acquired radioresistance.

Nitric oxide metabolites in induced sputum: a marker of airway inflammation in asthmatic subjects

BACKGROUND AND OBJECTIVE

The role of nitric oxide (NO) needs to be further clarified in allergic inflammation. This study was designed to investigate the relationships between NO metabolites and eosinophil count, eosinophil cationic protein (ECP), interleukin (IL)-5 in induced sputum from asthmatics.

METHODS

Hypertonic saline-induced sputum was obtained in 25 asthmatic subjects, among which 13 patients were examined before and after anti-asthmatic medications including steroid preparations. Ten normal subjects were enrolled as controls. Fresh expectorated sputum separated from saliva was treated with equal volume of dithiothreitol 0.1%, cytospinned for cell count, and the supernatant was collected for biochemical assay. NO metabolites were assayed by using modified Griess reaction. ECP was measured by fluoroimmunoassay, and detected IL-5 by a sandwich ELISA.

RESULTS

Asthmatic subjects, compared with controls, had significantly higher concentration of NO metabolites (1035.4 +/- 125.3 vs 557.2 +/- 101.5 micromol/L, P < 0.01), higher percentage of eosinophils (25.6 +/- 4.6 vs 1.7 +/- 0.2%, P < 0.01), and higher levels of ECP (1117.8 +/- 213.9 vs 154.6 +/- 47.4 microg/L, P < 0.01) in the induced sputum. IL-5 was detected more frequently in asthmatic subjects than in control subjects (11/25 [44%] vs 1/10 [10%], P < 0.05). According to asthma severity, moderate to severe asthmatic subjects (n = 18) had higher level of NO metabolites (1143.8 +/- 156.3 vs 575.5 +/- 89.5 micromol/L, P < 0. 01), higher levels of ECP and IL-5 (P < 0.01, respectively) in the induced sputum than in those of mild asthmatic subjects (n = 7). NO metabolites, the percentage of eosinophils, the levels of ECP, and IL-5 were reduced following treatment with anti-asthmatic drugs (P < 0.01, respectively). There were significant positive correlations between NO metabolites and percentage of eosinophils or ECP (r = 0. 34, P < 0.05; r = 0.28, P < 0.05). Negative correlations were noted between FEV1, FEV1/FVC and proportion of eosinophils, ECP, or IL-5 levels.

CONCLUSION

These findings confirmed that the level of NO metabolites was increased in the tracheobronchial secretion of asthmatic subjects and was paralleled with severity of asthma. Measurement of NO metabolites in induced sputum may be used for monitoring the degree of airway inflammation in asthmatics.

Nitric oxide synthase in the JGA of the SHR: expression and role in tubuloglomerular feedback

The spontaneously hypertensive rat (SHR) has an enhanced tubuloglomerular feedback (TGF) and a diminished buffering by juxtaglomerular apparatus (JGA)-derived NO. We examined the hypothesis that these effects are due to decreases in nitric oxide synthase (NOS) expression or limited availability of L-arginine or tetrahydrobiopterin (BH(4)). SHR had significantly (P < 0.05) greater mRNA abundance (by RT-PCR) or protein (by Western analysis) for neuronal NOS (nNOS, or type I) and endothelial cell NOS (ecNOS, or type III) in renal cortex or isolated glomeruli, respectively. There was prominent expression of ecNOS in glomerular endothelium and nNOS in macula densa. Maximal TGF responses, assessed from changes in proximal stop-flow pressure during orthograde loop of Henle (LH) perfusion, were greater in SHR [Wistar-Kyoto (WKY), 8.1 +/- 0.3 (n = 46) vs. SHR, 10.3 +/- 0.3 mmHg (n = 57); P < 0.001]. Unlike WKY, TGF responses of SHR were unresponsive to microperfusion of the nNOS inhibitor, 7-nitroindazole (7-NI, 10(-4) M) [WKY, 9.5 +/- 0.5 to 13.2 +/- 0.7 (n = 13, P < 0.001) vs. SHR, 11.8 +/- 0.7 to 12.5 +/- 0.6 mmHg (n = 19, not significant)], or to L-arginine (10(-3) M) [WKY, 7.7 +/- 0.8 to 6.3 +/- 0.4 (n = 10, P < 0.05) vs. SHR, 10.4 +/- 0.7 to 10.6 +/- 0.7 mmHg (n = 10, not significant)]. Neither BH(4) (10(-4) M) nor sepiapterin (10(-4) M), its stable precursor, modified TGF responses in WKY or in SHR, nor did they restore a response to microperfusion of 7-NI in SHR. In conclusion, there is a diminished role for NO from nNOS in blunting of TGF in SHR which cannot be ascribed to limited NOS expression or availability of substrate or BH(4).

Induction of cell-cycle arrest and apoptosis by a novel retinobenzoic-acid derivative, TAC-101, in human pancreatic-cancer cells

In this study, we investigated the effect of a novel retinobenzoic acid, 4-[3,5-bis (trimethylsilyl) benzamido] benzoic acid (TAC-101), on the growth of 4 human pancreatic-cancer cell lines; BxPC-3, MIAPaCa-2, CFPAC-1 and AsPC-1. TAC-101 significantly inhibited the proliferation of BxPC-3 and MIAPaCa-2 cells in a time- and concentration-dependent manner, but not the proliferation of AsPC-1 cells. Furthermore, the anti-proliferative effects of TAC-101 on BxPC-3 and MIAPaCa-2 cells were stronger than those of all-trans retinoic acid. Flow-cytometric analyses indicated that treatment of BxPC-3 with TAC-101 strongly induces cell-cycle arrest at the G1 phase. The cell-cycle arrest induced by TAC-101 was accompanied by reduction of retinoblastoma-gene product (RB) phosphorylation and an increase of 2 cyclin-dependent kinase (CDK) inhibitors, p21(WAF1/Cip1) (p21) and p27Kip1 (p27). TAC-101 also caused a decrease in cyclin A and thymidylate synthase, which are E2F-regulated gene products. No changes were observed in the expression of cyclin D1, cyclin E on CDK2. In addition, Hoechst staining, gel electrophoresis and flow-cytometric analysis indicated that a marked reduction in the number of BxPC-3 cells with TAC-101 was related to the induction of apoptosis. Our results suggest that TAC-101 inhibits the growth of certain pancreatic-cancer cells by means of G1-phase cell-cycle arrest resulting from the reduction of RB phosphorylation and the up-regulation of p21 and p27 as well as the induction of apoptosis. TAC-101 may therefore be a useful agent for new therapeutic strategies focusing on inhibition of pancreatic-cancer-cell proliferation.

Role of nitric oxide in the pathogenesis of diabetic nephropathy in streptozotocin-induced diabetic rats

OBJECTIVES

Several reports suggest that enhanced generation or actions of nitric oxide (NO) have been implicated in the pathogenesis of glomerular hyperfiltration and hyperperfusion that occurs in early diabetes. However, the precise role of altered NO generation in the pathogenesis of diabetic nephropathy is unclear. The present study was aimed at investigating the role of nitric oxide in the pathogenesis of glomerular hyperfiltration and hyperperfusion in streptozotocin-induced diabetic rats.

METHODS

To evaluate the role of NO in diabetic hyperfiltration, we measured plasma and urine concentrations of NO2-/NO3-, stable metabolic products of NO and protein expressions of three isoforms of nitric oxide synthase (NOS) in streptozotocin-induced diabetic rats. We also investigated renal hemodynamic changes, such as glomerular filtration rate (GFR) and renal plasma flow (RPF), in responses to acute and chronic administration of NO synthesis inhibitor, nitro-L-arginine methyl ester (L-NAME), in diabetic and control rats.

RESULTS

Diabetic rats exhibited significantly elevated plasma and urinary NO2-/NO3- levels at 28 days after streptozotocin injection, and total excretion of NO2-/NO3- was approximately five-fold higher in diabetic rats than controls. Insulin and L-NAME treatment prevented the increases in plasma and urinary NO2-/NO3- concentrations in diabetic rats, respectively. The three isoforms of NOS (bNOS, iNOS, and ecNOS) were all increased in the renal cortex, whereas they remained unaltered in the renal medulla at day 28. GFR and RPF were significantly elevated in diabetic rats, and acute and chronic inhibition of NO synthesis by L-NAME attenuated the renal hemodynamic changes (increases in GFR and RPF) in diabetic rats, respectively.

CONCLUSIONS

NO synthesis was increased due to enhanced NOS expression in diabetic rats, and chronic NO blockade attenuated renal hyperfiltration and hyperperfusion in diabetic rats. In addition, diabetic rats exhibited enhanced renal hemodynamic responses to acute NO inhibition and excreted increased urinary NO2-/NO3-. These results suggest that excessive NO production may contribute to renal hyperfiltration and hyperperfusion in early diabetes.

Altered renal expression of nitric oxide synthase isozymes in spontaneously hypertensive rats

OBJECTIVES

The present study was aimed at exploring whether the pathogenesis of hypertension is related with an altered expression of nitric oxide synthase (NOS) isozymes, i.e., bNOS, iNOS and ecNOS.

METHOD

By Western blot analysis, the expression of NOS isozymes were determined in the kidney isolated from spontaneously hypertensive rats (SHR) and their normotensive control, Wistar-Kyoto rats (WKY). The NOx (nitrite/nitrate) contents were also determined in the kidney and plasma.

RESULTS

The plasma NOx was significantly increased in SHR compared with that in WKY. The basal level of NOx was higher in the medulla and cortex of the kidney in SHR compared with that in WKY rat. bNOS proteins were expressed higher in the outer medulla and cortex, and iNOS proteins were higher in the inner medulla, outer medulla and cortex in SHR. ecNOS expression did not significantly differ between the SHR and WKY.

CONCLUSIONS

These results indicate that the NO generation may not be impaired, but rather increased. It is likely that the increased expression of NOS isozymes is a counter-reactive phenomenon secondary to the increased blood pressure in this model of hypertension.

Coexistence of coronary aneurysms and total occlusion of coronary arteries in systemic lupus erythematosus

A 22-year-old woman with known SLE and chronic hepatitis B developed anginal pain. During this period there was serologic but no other clinical evidence of active SLE. Myocardial perfusion SPECT showed a severe reversible perfusion defect in the posterior wall, and coronary angiography revealed multiple coronary aneurysms in the left anterior descending artery and circumflex artery and total occlusion of the proximal right coronary artery. This case suggests that coronary aneurysms and total occlusion may represent a sequela of arteritis, or of a combination of underlying vasculitis and a recent thrombotic obstruction due to antiphospholipid syndrome.

Expression of two angiogenic factors, vascular endothelial growth factor and platelet-derived endothelial cell growth factor in human pancreatic cancer, and its relationship to angiogenesis

Tumour angiogenesis, as assayed by microvessel density (MVD), and the expression of vascular endothelial growth factor (VEGF) and platelet-derived endothelial cell growth factor (PD-ECGF) have become established as important prognostic indicators for many tumour types. In this study, MVD and the expression of VEGF and PD-ECGF were examined by immunohistochemical staining of 50 pancreatic cancer tissues, and the relationships between either MVD or the expression of these two angiogenic factors and the clinicopathological features, including survival, were analysed. The expression of VEGF and PD-ECGF proteins were confirmed by Western blot analysis and VEGF mRNA isoforms were determined by reverse transcriptase-polymerase chain reaction (RT-PCR) in five pancreatic cancer cell lines. Twenty-eight (56%) of 50 pancreatic cancers were positive for VEGF protein in cancer cells, and 16 (32%) showed strong PD-ECGF staining in cancer and infiltrating cells. VEGF121 and VEGF165 were identified as the predominant species produced in pancreatic cancer cells. The overexpression of VEGF and PD-ECGF protein significantly correlated with high MVD (P = 0.002, 0.044, respectively). Advanced stage of disease was significantly more frequent in patients with high MVD (P = 0.025). No significant association was found between the expression of VEGF or PD-ECGF and clinicopathological features, except for tumour histology. The expression of PD-ECGF correlated with poor survival (P = 0.011), but MVD and VEGF expression were not found to be useful for the prediction of overall survival. This study suggests that VEGF and PD-ECGF may play an important role in tumour angiogenesis, and that PD-ECGF expression seems to be useful for establishing prognoses for pancreatic cancer.

A case of arteriovenous type cardiac hemangioma

Cardiac hemangiomas are rare primary tumors of the heart and constitute only 2.8% of primary cardiac tumors. They are classified into capillary, cavernous, epitheloid and arteriovenous type and the last one is the most uncommon type. We experienced a case of cardiac hemangioma which was diagnosed as arteriovenous type for the first time in Korea in the literature. The patient was a 54-year-old woman who presented with palpitation and anterior chest pain. The diagnosis was based upon coronary angiography which showed two tumor blushings located in the interatrial and interventricular septum with venous drainage to the coronary sinus and right atrium. Associated atrial fibrillation with rapid ventricular response was controlled with digitalis.

An exogenous cdk inhibitor, butyrolactone-I, induces apoptosis with increased Bax/Bcl-2 ratio in p53-mutated pancreatic cancer cells

We investigated the effects of an exogenous cdk inhibitor, butyrolactone-I, on cell growth inhibition, apoptosis induction, and the regulation of apoptosis in pancreatic cancer cells with mutated p53. Cell growth was dose-dependently inhibited by Butyrolactone-I in PANC-1 and AsPC-1 cells. Phosphorylation of pRb and Cyclin A expression were significantly inhibited in Butyrolactone-I-treated cells. Apoptotic cell death was detected by both Hoechst staining and TUNEL assay. In butyrolactone-I-treated PANC-1 cells, expression of p53 protein was unchanged, but Bax expression was slightly upregulated and Bcl-2 expression was predominantly down-regulated. Bax/Bcl-2 ratio reached 9.6-fold increase compared to the control at the maximum. The time course of changes in Bax/Bcl-2 ratio was similar to that in the TUNEL-positive ratio. These data, suggest that dynamic changes of the Bax/Bcl-2 ratio might be important in determining point of apoptosis induction in pancreatic cancer cells with p53 mutation.

The role of platelet-activating factor in regional myocardial ischemia-reperfusion injury

BACKGROUND

This swine model was designed to elucidate the role of platelet-activating factor in regional myocardial ischemia-reperfusion injury.

METHODS

In groups 1 and 2 (n = 12 each), the left anterior descending coronary artery was ligated for 60 minutes to induce regional myocardial ischemia followed by 6 hours of reperfusion. Group 1 received the platelet-activating factor antagonist TCV-309 before ischemia, whereas group 2 did not. Group 3 (n = 3) had a sham operation.

RESULTS

Animals in group 2 exhibited significant (p < 0.05) hemodynamic instability and myocardial depression during the reperfusion period. Despite preventive measures, 7 of the 12 animals experienced severe dysrhythmias in the form of atrial and ventricular fibrillation leading to cardiac arrest. In contrast, animals in group 1 in whom the effects of platelet-activating factor were blocked by the specific platelet-activating factor receptor antagonist TCV-309 were hemodynamically stable and had significantly (p < 0.05) better myocardial function. This significant difference in global myocardial function between the groups was observed in the presence of similar morphologic findings and regional myocardial function.

CONCLUSIONS

These results suggest that platelet-activating factor has a definite influence on global myocardial dysfunction associated with regional myocardial ischemia-reperfusion injury.

Involvement of matrix metalloproteinase-2 activity in invasion and metastasis of pancreatic carcinoma

BACKGROUND

Activation of matrix metalloproteinase-2 (MMP-2) has been implicated in the progression, invasion, and metastasis of various cancers, but little information is available with regard to its role in pancreatic carcinoma with poor prognosis.

METHODS

Gelatin zymography was used for the detection of latent and activated forms of MMP-2 and MMP-9 in 13 normal pancreatic tissue specimens, 14 chronic pancreatitis tissue specimens, and 33 pancreatic carcinoma tissue specimens. The gelatinase activity was quantified by densitometer, and the 66-kilodalton (kDa)/(66-kDa + 72-kDa) ratio was calculated as the MMP-2 activation ratio. Western blot analysis was performed to confirm the zymographic profile.

RESULTS

Latent forms of MMP-2 and MMP-9 were detected in all samples of pancreatic carcinoma, chronic pancreatitis, and normal pancreatic tissue. The expression rate of the MMP-2 activated form in pancreatic carcinoma tissue specimens was 100% (33 of 33) but that of MMP-9 was 21%. The MMP-2 activation ratio in pancreatic carcinoma tissue specimens was significantly higher than that of chronic pancreatitis and normal pancreatic tissue specimens. The MMP-2 activation ratio in pT3 tumors was significantly higher than that in pT1 tumors. The MMP-2 activation ratio also was significantly higher in pancreatic carcinoma specimens with histologically positive regional lymph node metastasis and distant metastasis than those without metastasis. The MMP-2 activation ratio observed in patients who developed postresection recurrence within 6 months was significantly higher than that in patients without recurrence at 6 months.

CONCLUSIONS

The results of the current study indicate that MMP-2 activation plays a significant role in tumor invasion and metastasis in pancreatic carcinoma.

Involvement of matrix metalloproteinase-2 activity in invasion and metastasis of pancreatic carcinoma

BACKGROUND

Activation of matrix metalloproteinase-2 (MMP-2) has been implicated in the progression, invasion, and metastasis of various cancers, but little information is available with regard to its role in pancreatic carcinoma with poor prognosis.

METHODS

Gelatin zymography was used for the detection of latent and activated forms of MMP-2 and MMP-9 in 13 normal pancreatic tissue specimens, 14 chronic pancreatitis tissue specimens, and 33 pancreatic carcinoma tissue specimens. The gelatinase activity was quantified by densitometer, and the 66-kilodalton (kDa)/(66-kDa + 72-kDa) ratio was calculated as the MMP-2 activation ratio. Western blot analysis was performed to confirm the zymographic profile.

RESULTS

Latent forms of MMP-2 and MMP-9 were detected in all samples of pancreatic carcinoma, chronic pancreatitis, and normal pancreatic tissue. The expression rate of the MMP-2 activated form in pancreatic carcinoma tissue specimens was 100% (33 of 33) but that of MMP-9 was 21%. The MMP-2 activation ratio in pancreatic carcinoma tissue specimens was significantly higher than that of chronic pancreatitis and normal pancreatic tissue specimens. The MMP-2 activation ratio in pT3 tumors was significantly higher than that in pT1 tumors. The MMP-2 activation ratio also was significantly higher in pancreatic carcinoma specimens with histologically positive regional lymph node metastasis and distant metastasis than those without metastasis. The MMP-2 activation ratio observed in patients who developed postresection recurrence within 6 months was significantly higher than that in patients without recurrence at 6 months.

CONCLUSIONS

The results of the current study indicate that MMP-2 activation plays a significant role in tumor invasion and metastasis in pancreatic carcinoma.

A human case of tick bite by Ixodes nipponensis

A human case of the tick bite on the back of 36-year-old man was found in September 1995. On admission he complained of itching sensation and pain at the site. The removed tick was identified morphologically as Ixodes nipponensis.

Involvement of matrix metalloproteinase-2 activity in invasion and metastasis of pancreatic carcinoma

BACKGROUND

Activation of matrix metalloproteinase-2 (MMP-2) has been implicated in the progression, invasion, and metastasis of various cancers, but little information is available with regard to its role in pancreatic carcinoma with poor prognosis.

METHODS

Gelatin zymography was used for the detection of latent and activated forms of MMP-2 and MMP-9 in 13 normal pancreatic tissue specimens, 14 chronic pancreatitis tissue specimens, and 33 pancreatic carcinoma tissue specimens. The gelatinase activity was quantified by densitometer, and the 66-kilodalton (kDa)/(66-kDa + 72-kDa) ratio was calculated as the MMP-2 activation ratio. Western blot analysis was performed to confirm the zymographic profile.

RESULTS

Latent forms of MMP-2 and MMP-9 were detected in all samples of pancreatic carcinoma, chronic pancreatitis, and normal pancreatic tissue. The expression rate of the MMP-2 activated form in pancreatic carcinoma tissue specimens was 100% (33 of 33) but that of MMP-9 was 21%. The MMP-2 activation ratio in pancreatic carcinoma tissue specimens was significantly higher than that of chronic pancreatitis and normal pancreatic tissue specimens. The MMP-2 activation ratio in pT3 tumors was significantly higher than that in pT1 tumors. The MMP-2 activation ratio also was significantly higher in pancreatic carcinoma specimens with histologically positive regional lymph node metastasis and distant metastasis than those without metastasis. The MMP-2 activation ratio observed in patients who developed postresection recurrence within 6 months was significantly higher than that in patients without recurrence at 6 months.

CONCLUSIONS

The results of the current study indicate that MMP-2 activation plays a significant role in tumor invasion and metastasis in pancreatic carcinoma.

Role of neutrophils in cerulein-induced pancreatitis in rats: possible involvement of apoptosis

We investigated the role of neutrophils and the involvement of apoptosis in cerulein-induced acute pancreatitis. Male Sprague-Dawley rats were divided into 2 groups. In the control group, acute pancreatitis was induced by subcutaneous injections of cerulein. In methotrexate-treated group, the rats received intraperitoneal injections of methotrexate to produce neutrophil depletion before the injections of cerulein. The rats were sacrificed at the indicated time points until 72 h after the first injection of cerulein. Neutrophil depletion ameliorated pancreatic edema and vacuole formation in acinar cells during the early stages of cerulein-induced acute pancreatitis. Electron microscopy, DNA gel electrophoresis and in situ nick end-labeling revealed the involvement of apoptosis in acinar cells in cerulein-induced acute pancreatitis. Furthermore, the number of apoptotic acinar cells in neutrophil-depleted rats showed an about 2-fold increase during the late stages when compared with those in the control rats. Our results suggest that neutrophil depletion in cerulein-induced pancreatitis leads to amelioration of pancreatic injury during the early stage, and enhancement of apoptosis by neutrophil depletion occurs during the late stage.

Mechanism of apoptosis induced by cisplatin and VP-16 in PANC-1 cells

Cisplatin and VP-16 were used to study the induction of apoptosis in Panc-1 cells. Cisplatin and VP-16 inhibited the growth of Panc-1 cells. After 2 hours exposure to cisplatin or VP-16, attached and detached cells were subjected to TUNEL staining to calculate the ratio of apoptosis. In detached cells TUNEL positive ratios increased in a time- and dose-dependent manner. In Western blotting, Bax expression was obviously up-regulated, but Bcl-2 remained almost constant. The results suggested that in Panc-1 cells cisplatin and VP-16 induced apoptotic cell death which was mediated through the interaction of Bax expression in the presence of mutated p53.

Expression of Bcl-2 and PCNA in duct cells after pancreatic duct ligation in rats

Obstruction of the pancreatic duct induces acinar cell deletion followed by duct proliferation and interstitial fibrosis. Apoptosis has been reported to be involved in the induction of acinar cell deletion after pancreatic duct ligation (PDL) in rats, however, the mechanism of pancreatic duct cell proliferation is still unknown. We hypothesized that Bcl-2 (antiapoptosis protein) and PCNA (cell cycle-related protein) could be involved in the mechanism of pancreatic duct cell proliferation after PDL. In PDL, rats, acinar cells decreased in number and disappeared completely after duct ligation and duct-lining cells increased in number and formed duct-tubular complexes. Immunohistochemical study showed that PCNA expression appeared in the ductules and centroacinar cells from early stages after duct ligation and that Bcl-2 expression in duct cells, which was faint in normal pancreas, increased significantly when acinar cells were diminishing. Western blotting demonstrated that Bcl-2 was detected as a single band at 26 kDa, and the intensity of Bcl-2 in PDL rats was approximately ninefold stronger than in normal pancreas. Expression of Bcl-2 and PCNA after pancreatic duct ligation may be related to the prevention of apoptosis and cell proliferation of pancreatic duct cells in rats.

Effects of altered body fluid balance and high blood pressure on the plasma brain natriuretic peptide in rats

The present study was aimed to investigate the regulatory mechanisms of BNP release. Effects of acute and chronic perturbations in body fluid balance, changes in BP, and regulatory roles of NO and endothelin systems on BNP release were examined in rats. Although acute extracellular volume expansion did not have significant effects on plasma BNP, prolonged high-salt intake increased plasma BNP levels. Plasma BNP levels were also higher in 2K1C rats compared with the control. Although infusion of L-NAME increased the plasma BNP in control, it did not further affect the plasma BNP in rats with high-salt intake. Although L-arginine (20 mg.kg-1 per min) per se did not have significant effects on plasma BNP, it blocked the stimulatory effect of L-NAME (200 micrograms.kg-1 per min). Plasma BNP was severalfold increased following a single injection of endothelin (0.3 micrograms/kg) in normal and high-salt intake groups, the magnitude of which was not significantly affected by the high-salt intake. Although indomethacin did not have significant effects on plasma BNP in normal rats, it blocked the stimulatory effect of 2K1C hypertension. It is concluded that BNP is regulated by chronic changes in body fluid balance and blood pressure. It is also suggested that endothelin and NO systems may directly regulate the secretion of BNP in vivo. An endogenous prostaglandin synthesis may be involved in the stimulated release of BNP in hypertension.

Space-resolving flat-field extreme ultraviolet spectrograph system and its aberration analysis with wave-front aberration

The Nam aberration of a flat-field extreme ultraviolet spectrograph system, composed of a varied line-spacing concave grating and a toroidal mirror, was analyzed by calculating the wave-front aberration with respect to an astigmatic reference surface. The toroidal mirror was used to compensate for the astigmatism that was due to the grazing incidence of light at the concave grating. The spectrograph system could form a space-resolved spectrum along the sagittal direction. The spectral and spatial resolutions of the spectrograph system were estimated from the root-mean-square spot size. The actual spectral resolution of the spectrograph system was measured from extreme ultraviolet spectra obtained from plasmas produced by an iodine laser having an energy of 0.5 J in a 4-ns duration, and it was compared with the calculated value.

Changes of the plasma endothelin in adaptation to increased salt intake in rats

OBJECTIVES

Roles for vascular endothelial hormones in body fluid balance have been variously suggested. The present study was aimed at investigating whether the plasma endothelin is altered in responses to acute and chronic perturbations in body fluid balance.

METHODS

Effects of intravenous infusion of MG-nitro-L-arginine methyl ester (L-NAME), a competitive inhibitor of endothelium-derived nitric oxide (NO) synthesis, on urinary excretion, blood pressure and plasma levels of endothelin were examined in rats kept on either normal or high-salt diet for two weeks. The plasma endothelin levels in response to an acute extracellular volume expansion (VE) were also determined in normal and 2-kidney, 1 clip (2K1C) hypertensive rats.

RESULTS

L-NAME (20 and 200 micrograms.kg(-1) per min) elicited diuretic and natriuretic effects in association with increased blood pressure both in normal and high-salt rats. In high-salt rats, however, the urinary response to L-NAME was attenuated and the pressor response was augmented compared with the control. High-salt intake per se caused a small, but significant, increase of the plasma endothelin. L-NAME (200 micrograms(-1) per min) markedly increased the plasma endothelin was also marginally increased following VE, the magnitude of which did not differ between the normal and 2K1C rats.

CONCLUSION

These results suggest that the endothelin system takes part in adaptation to increased salt-intake. Another evidence indicating a negative modulation of NO on the release of endothelin is also provided.

Role of apoptosis in duct obstruction-induced pancreatic involution in rats

It has been recognized in mammals that after pancreatic duct obstruction, acinar cells progressively disappear and pancreatic islets are preserved. Previous studies by electron microscopy have suggested the involvement of apoptosis in acinar cell deletion. In the present study, we employed molecular biological methods and investigated whether acinar cell deletion is due to apoptosis. In male Sprague-Dawley rats, pancreatic duct ligation was performed through a left paramedian incision. Pancreatic tissue was studied at each of the following intervals after ligation: 3, 6, 12, 18, and 24 h and 2, 3, 5, and 7 days. DNA fragmentation was determined by in situ labeling of DNA strand breaks on tissue sections [fluorescein-labeled terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling method (TUNEL)] and by electrophoretic detection of the fragments of extracted DNA. Tissue sections were also examined by hematoxylin/eosin staining and immunohistochemical staining of insulin. Pancreatic duct ligation induced acinar cell deletion by day 5. Pancreatic tissue from control rats demonstrated no TUNEL-positive nuclei. In contrast, acinar cells from rats 12 h to 5 days after duct ligation showed TUNEL-positive nuclei. The number of TUNEL-positive nuclei was maximum 2 days after duct ligation. Electrophoresis showed DNA fragmentation after duct ligation. Control rats showed a genomic DNA pattern. Islets were preserved throughout the experimental period in duct-ligated rats and control rats. The results suggest that apoptosis may be the dominant form of acinar cell death in the rat pancreatic duct ligation model.

Detection of matrix metalloproteinase activity in human pancreatic cancer

Destruction of the basement membrane (BM) is mandatory for tumor spread, and matrix metalloproteinases (MMPs) are known to be implicated in colon cancer invasion and metastasis by digesting type IV collagen, a main component of the BM. The current study analyzed the expression of MMP-2 and MMP-9 in pancreatic cancer tissues. Frozen specimens of pancreatic cancer (n = 10), a liver metastatic nodule from pancreatic cancer (n = 1), and normal pancreas (n = 3) were homogenized and analyzed by zymography. The activated form of MMP-9 (82 kDa) was detected in all of the normal and malignant tissues, while the activated form of MMP-2 (62 kDa) was detected in all of the pancreatic cancers and its metastatic tissue, but not in the normal pancreatic tissues. These results indicate that expression of the activated form of MMP-2 may be specific to pancreatic cancer, while that of MMP-9 may be unrelated to it.

Attenuated central pressor response to nitric oxide synthesis inhibition in chronic renal failure rats

OBJECTIVES

Central and peripheral roles of nitric oxide (NO) in blood pressure regulation have been suggested. The present study was aimed at examining if the role of NO in blood pressure regulation is altered in chronic renal failure.

METHODS

Blood pressure responses to acute inhibition of NO were examined in 5/6 nephrectomized rats. Three weeks after the renal ablation, under thiopental (50 mg/kg, i.p.) anesthesia, an intracerebroventricular cannula was placed in the left lateral ventricle and the femoral vein was cannulated to serve as an infusion route. The arterial blood pressure was measured in the right femoral artery. NG-nito-L-arginine methyl ester (L-NAME) was infused (100 microgram/kg per min for 60 min either intracerebroventricularly or intravenously.

RESULTS

Chronic renal failure rats showed a significantly higher arterial pressure than the control rats (147 +/- 14 mmHg vs. 122 +/- 13 mmHg). Intracerebroventricular L-NAME did not affect the arterial pressure in chronic renal failure rats (0.5 +/- 4 mmHg increase from the basal), while it significantly increased the arterial pressure in normal rats (22 +/- 3 mmHg increases from the basal). Intravenous L-NAME increased the arterial pressure, the magnitude of which did not differ between the normal and chronic renal failure rats (24 +/- 3 vs. 16 +/- 3 mmHg increases from the basal).

CONCLUSION

These results indicate that the central role of NO in the regulation of blood pressure is altered in chronic renal failure.

Effects of structural modulation on biological activity of bombesin analogues with (E)-alkene bond

The specific bombesin receptor antagonist, (E)-alkene bombesin isostere (EABI-1), [D-Phe6,Leu13psi[(E)CH=CH]Leu14]bombesin(6-14) is a potent antagonist in terms of inhibition of bombesin-stimulated amylase release from rat pancreatic acini. This study examined the effects of EABI-1 (L-L diastereomer) and three novel bombesin analogues on amylase release in rat pancreatic acini. EABI-2 is a L-D diastereomer of EABI-1. EABI-3 is an analogue, of which leucine at position 13 of EABI-1 was replaced with valine. EABI-4 is a L-D diastereomer of EABI-3 (L-L). The order of agonist potency was EABI-2>EABI-3>EABI-4. EABI-1 showed no agonist activity at concentrations up to 100nM. On the other hand, all of four analogues had antagonist activity. The order of antagonist potency was EABI-1>EABI-3>EABI-4>EABI-2. EABI-1 was a complete antagonist, EABI-2 and EABI-3 were partial agonists, and EABI-4 had a weak agonist effect. The present study provides a useful information on the future development of peptide analogues for anticancer agents and biological tools for investigating actions of bombesin family peptides.

PR interval behavior during exercise stress test

OBJECTIVES

The PR interval on the electrocardiogram represents conduction time from the onset of atrial activation through His-Purkinje conduction system during a normal cardiac cycle. While its behavior at rest and during exposure to various cardioactive drugs is well documented, there exist few reports which describe PR interval variations during exercise in normal control and patient groups. In the present study, we examined the behavior of the PR intervals during various stages of exercise, and at the same time we observed whether the changes of PR interval during exercise could suggest that implanted cardiac pacemaker algorithms may be constructed to maximize hemodynamic benefits in patients requiring physiological cardiac pacemaker.

METHODS

A retrospective analysis of the exercise treadmill test was performed on 148 healthy control group (148 males, mean age of 42.7 +/- 11.7) and 134 patient group (95 males & 39 females, mean age of 47.1 +/- 11.7) which had complained of non-specific chest symptoms but were identified as normal in the exercise treadmill test. During the test, we used the standard Bruce protocol. The results were expressed as mean +/- standard deviation, and differences in the mean value of each standard deviation, and differences in the mean value of each group were evaluated by the student's t-test. A P value of less than 0.05 was regarded as significant.

RESULTS

1) The control group showed 6.9msec reduction rate of the PR interval whenever their heart rate increased by 10 beats per minute. 2) The entire patients group showed 5msec reduction rate of the PR interval whenever their heart rate increased by 10 beats per minute. 3) The male patients group showed 5.2msec reduction rate of the PR interval whenever their heart rate increased by 10 beats per minute. 4) The female patient group showed 4.3msec reduction rate of the PR interval whenever their heart rate increased by 10 beats per minute. 5) There were significant differences of the PR interval changes between the entire or male patient group and the control group within the same range of heart rates.

CONCLUSIONS

This study shows that PR interval changes corresponding to heart rate increments were linearly decreased. These changes of PR interval during exercise suggest that implanted cardiac pacemaker algorithms may be constructed to maximize hemodynamic benefits in patients requiring physiological cardiac pacemakers.

Effect of aperture modulation on the MTF of a binocular objective having off-axis aberrations

Aperture modulation effects have been investigated in a Korean binocular objective lens in isolation from the rest of the system. The off-axis aberrations are derived from the design data. The MTFs are measured for the same modulated aperture and compared by the same method, in the presence of off-axis aberrations, as the rotationally symmetric aberrations presented in the previous paper [Appl. Opt. 22, 1812 (1983)]. The MTF of the lens was found to be improved by proper aperture modulation.