Development and potential of non-peptide antagonists for calcitonin-gene-related peptide (CGRP) receptors: evidence for CGRP receptor heterogeneity

Calcitonin-gene-related peptide (CGRP) is a 37-amino-acid vasodilatory peptide, of which two isoforms, alpha CGRP and beta CGRP, have been described. The use of C-terminal fragments of CGRP peptide, such as human alpha CGRP-(8-37), has led to the pharmacological subdivision of CGRP receptors into CGRP-1 [high potency for binding of human alpha CGRP-(8-37)] and CGRP-2 (lower potency) receptors. We have recently developed BIBN4096BS, the first non-peptide CGRP antagonist, which has sub-nanomolar affinity for primate CGRP receptors. The use of BIBN4096BS has led to the discovery of further functional CGRP receptor heterogeneity in rat tissues. To further exploit BIBN4096BS as a pharmacological tool, we used BIBN4096BS in pig left anterior descending coronary vessels and cerebral basilar arteries, and compared functional with molecular data, characterizing CGRP receptor components. Our data show that, apart from a subdivision into CGRP-1 and -2 receptors, BIBN4096BS reveals additional functional differences between the actions of alpha CGRP and beta CGRP. However, evidence for CGRP receptor heterogeneity on a molecular level is scarce.

Boundary element method-based cortical potential imaging of somatosensory evoked potentials using subjects' magnetic resonance images

A boundary element method-based cortical potential imaging technique has been developed to directly link the scalp potentials with the cortical potentials with the aid of magnetic resonance images of the subjects. First, computer simulations were conducted to evaluate the new approach in a concentric three-sphere inhomogeneous head model. Second, the corresponding cortical potentials were estimated from the patients' preoperative scalp somatosensory evoked potentials (SEPs) based on the boundary element models constructed from subjects' magnetic resonance images and compared to the postoperative direct cortical potential recordings in the same patients. Simulation results demonstrated that the cortical potentials can be estimated from the scalp potentials using different scalp electrode configurations and are robust against measurement noise. The cortical imaging analysis of the preoperative scalp SEPs recorded from patients using the present approach showed high consistency in spatial pattern with the postoperative direct cortical potential recordings. Quantitative comparison between the estimated and the directly recorded subdural grid potentials resulted in reasonably high correlation coefficients in cases studied. Amplitude difference between the estimated and the recorded potentials was also observed as indexed by the relative error, and the possible underlying reasons are discussed. The present numerical and experimental results validate the boundary element method-based cortical potential imaging approach and demonstrate the feasibility of the new approach in noninvasive high-resolution imaging of brain electric activities from scalp potential measurement and magnetic resonance images.

Building a mouse model hallmarking the congenital human cytomegalovirus infection in central nervous system

To investigate the mechanisms that human cytomegalovirus (HCMV) can vertically transmit from the placenta of mice to infect their offspring in the central nervous system (CNS) and cause congenital anomalies, and in order to provide basic research for preparing HCMV vaccine, we have developed a new type of mouse model of HCMV congenital CNS infection. Pure strain mice were propagated after being infected with HCMV. Then the degree of infection by HCMV to offspring was determined. The experiment shows that in the infection groups the mortality of fetal mice and the fatality of neonatal mice in one week are higher than that of the control groups (P < or = 0.05). At the same time we investigated the CNS of fetus's mice whose mothers were infected by HCMV. Our results showed: 1. The virus was successfully isolated from their cerebral cortex. 2. The signal of HCMV hybridization print was found in their nervous cell through in situ hybridization. 3. Especially human herpes virus-like particles and inclusion bodies in the plasm of nerve cell were found in the tissue of their brain under the electron microscope. This new type of mouse model of HCMV inherent CNS infection will help prepare HCMV vaccine and research HCMV congenital infection in CNS.

An equivalent current source model and laplacian weighted minimum norm current estimates of brain electrical activity

We have developed a method for estimating the three-dimensional distribution of equivalent current sources inside the brain from scalp potentials. Laplacian weighted minimum norm algorithm has been used in the present study to estimate the inverse solutions. A three-concentric-sphere inhomogeneous head model was used to represent the head volume conductor. A closed-form solution of the electrical potential over the scalp and inside the brain due to a point current source was developed for the three-concentric-sphere inhomogeneous head model. Computer simulation studies were conducted to validate the proposed equivalent current source imaging. Assuming source configurations as either multiple dipoles or point current sources/sinks, in computer simulations we used our method to reconstruct these sources, and compared with the equivalent dipole source imaging. Human experimental studies were also conducted and the equivalent current source imaging was performed on the visual evoked potential data. These results highlight the advantages of the equivalent current source imaging and suggest that it may become an alternative approach to imaging spatially distributed current sources-sinks in the brain and other organ systems.

Cyclooxygenase enzyme inhibitory compounds with antioxidant activities from Piper methysticum (kava kava) roots

Cyclooxygenase enzyme inhibitory assay-guided purification of ethyl acetate extract of Piper methysticum (kava kava) roots yielded six biologically active compounds (1-7), which were purified using MPLC, preparative TLC and HPLC methods. These compounds were also evaluated for antioxidant activities. Dihydrokawain (1) and yangonin (6) showed the highest COX-I and COX-II inhibitory activities at 100 microg/ml, respectively. The lipid oxidation assay did not reveal antioxidant activities for demethoxyangonin (2), dihydrokawain (1), kawain (4), dihydromethysticin (5) or methysticin (7) at 50 microg/ml. The antioxidant activities of flavokawain A (3) and yangonin (6) could not be tested in the lipid oxidation assay due to solubility problems. However, yangonin and methysticin showed moderate antioxidant activities in the free radical scavenging assay at 2.5 mg/ml.

CYP2E1-dependent toxicity and oxidative stress in HepG2 cells

Induction of CYP2E1 by ethanol is one of the central pathways by which ethanol generates a state of oxidative stress in hepatocytes. To study the biochemical and toxicological actions of CYP2E1, our laboratory established HepG2 cell lines which constitutively overexpress CYP2E1 and characterized these cells with respect to ethanol toxicity. Addition of ethanol or an unsaturated fatty acid such as arachidonic acid or iron was toxic to the CYP2E1-expressing cells but not control cells. This toxicity was associated with elevated lipid peroxidation and could be prevented by antioxidants and inhibitors of CYP2E1. Apoptosis occurred in the CYP2E1-expressing cells exposed to ethanol, arachidonic acid, or iron. Removal of GSH caused a loss of viability in the CYP2E1-expressing cells even in the absence of added toxin or pro-oxidant. This was associated with mitochondrial damage and decreased mitochondrial membrane potential. Surprisingly, CYP2E1-expressing cells had elevated GSH levels, due to transcriptional activation of gamma glutamyl cysteine synthetase. Similarly, levels of catalase, alpha-, and microsomal glutathione transferase were also increased, suggesting that upregulation of these antioxidant genes may reflect an adaptive mechanism to remove CYP2E1-derived oxidants. While it is likely that several mechanisms contribute to alcohol-induced liver injury, the linkage between CYP2E1-dependent oxidative stress, mitochondrial injury, and GSH homeostasis may contribute to the toxic action of ethanol on the liver. HepG2 cell lines overexpressing CYP2E1 may be a valuable model to characterize the biochemical and toxicological properties of CYP2E1.

Gene structure and expression of the mouse adipocyte enhancer-binding protein

The adipocyte enhancer-binding protein (AEBP1) is a transcriptional repressor with carboxypeptidase activity. AEBP1 expression is down-regulated during adipogenesis. Aortic carboxypeptidase-like protein (ACLP) is a non-nuclear isoform of AEBP1 that has an N-terminal extension of 380 amino acids. ACLP expression is up-regulated during vascular smooth muscle cell differentiation. To gain insight into the regulation of AEBP1 isoform expression, we have determined the structural organization of the mouse AEBP1 gene. This gene extends over 10 kb, has 21 exons, and gives rise to two mRNAs (AEBP1 and ACLP). The 9th intron is retained in the mature AEBP1 transcript. Thus, ACLP encodes an additional 380 amino acids N-terminal to the first ATG codon of AEBP1 which is located in exon 10. RT-PCR experiments showed that both transcripts are expressed ubiquitously in all mouse tissues examined, while Western blot analysis suggested that expression is translationally regulated. Our results provide evidence that two isoforms of AEBP1 with very different functions are produced by an alternative splicing mechanism. This represents a new example of regulation of subcellular localization by protein truncation.

Torsade de pointes induced by metoclopramide in an elderly woman with preexisting complete left bundle branch block

There is a growing list of drugs implicated in acquired long QT syndrome and torsade de pointes. However, the torsadogenic potential of metoclopramide, a commonly used antiemetic and prokinetic drug, has not been reported in the literature, despite its chemical similarity to procainamide. We report on a 92-year-old woman with preexisting complete left bundle branch block who developed torsade de pointes after intravenous and oral administration of metoclopramide. This patient also developed torsade de pointes when cisapride and erythromycin were given simultaneously. These two episodes were suppressed successfully after discontinuing the offending drugs and administering class IB drugs. This is the first documentation that metoclopramide provokes torsade de pointes clinically. Metoclopramide should be used cautiously in patients with a risk of torsade de pointes.

Testing the independence of two diagnostic tests

Consider two diagnostic procedures having binary outcomes. If one of the tests results in a positive finding, a more definitive diagnostic procedure will be administered to establish the presence or absence of a disease. The use of both tests will improve the overall screening sensitivity when the two tests are independent, compared with employing two tests that are positively correlated. We estimate the correlation coefficient of the two tests and derive statistical methods for testing the independence of the two diagnostic procedures conditional on disease status. The statistical tests are used to investigate the independence of mammography and clinical breast exams aimed at establishing the benefit of early detection of breast cancer. The data used in the analysis are obtained from periodic screening examinations of three randomized clinical trials of breast cancer screening. Analysis of each of these trials confirms the independence of the clinical breast and mammography examinations. Based on these three large clinical trials, we conclude that a clinical breast exam considerably increases the overall sensitivity relative to screening with mammography alone and should be routinely included in early breast cancer detection programs.

[The measurement of multifocal electroretinography]

PURPOSE

Discussing the testing procedure of multifocal electroretinography(ERG).

METHODS

The testing procedure of 131 multifocal ERG records was reviewed.

RESULTS

Some variable factors existed in the measurement of multifocal ERG. These factors included the subject's co-operation, the mounting of electrode, the fixation of tested eye and adjustment of focus. The good records of multifocal ERG depend upon the skill of the operator.

CONCLUSION

The testing procedure of multifocal ERG must be standardized so as to ensure the reliability and repeatability of the results.

[Changes serum level of tumor specific growth factor and their clinical significance in mechanical trauma patients]

OBJECTIVE

To investigate the post-traumatic changes in the serum level of tumor specific growth factor (TSGF) and their relationship with Injury Severity Score and to inquire into the possible mechanism and clinical significance.

METHODS

Fifty patients with mechanical trauma were eligible and included. According to the standard of Injury Severity Score (ISS), the patients were divided into there groups: mild degree group, (ISS < or = 16, n = 31) severe degree group (16 < ISS < 25, n = 13) extreme severe degree group (ISS > or = 25, n = 6). The blood samples of all patients were obtained within 24 hours, and those of 25 dynamically observed patients were obtained on days 3, 5, 7, 9 and 12.

RESULTS

The serum level of TSGF was significantly higher in patients with trauma in different groups (P < 0.05). The dynamical observation showed that the index demonstrated curve changes with increase in early stage and decrease later. the climax of TSGF appeared on 7 day in all 3 groups. The TSGF serum levels in extremely severe degree and severe degree groups > mild degree group on days 5, 7, 9 and 12 day (P < 0.05).

CONCLUSION

TSGF has relationship with the inflammatory response and recovery of trauma.

Potentiation of docetaxel antitumor activity by batimastat against mouse forestomach carcinoma

OBJECTIVE

To improve the treatment of tumors, we studied the combined effects of docetaxel and batimastat (BB-94) on mouse forestomach carcinoma (MFC), and compared them with doxorubicin.

METHODS AND RESULTS

In vitro, growth curve analysis, MTT assay and clonogenic assay used to determine the cytotoxic effect of docetaxel or/and BB-94 on MFC cell showed that docetaxel but not BB-94 had a significant cytotoxicity, and the effect of docetaxel wasn't enhanced by BB-94. In early stage MFC tumor model, obvious antitumor effect of docetaxel or doxorubicin given i.v. at maximum tolerated dose (MTD, docetaxel: 20 mg/kg; doxorubicin: 6 mg/kg) every 4 days for 3 injections (q4d x 3), even that of BB-94 (30 mg/kg i. p. qd x 20) was observed. Tumor growth inhibition was greater for docetaxel-batimastat (96.0%) than for doxorubicin-batimastat (88.0%), docetaxel (89.0%), doxorubicin (68.0%) and BB-94 (33.0%), and the effect of docetaxel could be potentiated by BB-94. Docetaxel also showed activity against advanced stage MFC tumor in dose-dependent manner, and was more effective at MTD than doxorubicin with 4/5 regressions, 46.5 days tumor growth delay and 2.8log(10) tumor cell kill.

CONCLUSION

Our results suggest that in the MFC model with dose and schedule used, docetaxel is an effective cytotoxic new drug against MFC tumor and BB-94 enchances the antitumor activity of docetaxel.

[Is hepatic ultrasonography necessary in the initial check-up of patients with squamous cell carcinoma of the upper respiratory and digestive tract?]

PURPOSE OF THE STUDY

The purpose of our study was to determine the position and value of ultrasound scan of the liver in the initial check-up of patients treated for a squamous cell carcinoma of the upper respiratory and digestive tract.

MATERIAL AND METHODS

Our study is based on a retrospective review of 267 patients (249 males and 18 females) managed in the E.N.T. Department of Grenoble universitary hospital from 1993 to 1995 for a upper respiratory and digestive tract malignant tumor. No patient has been previously treated. The site of the primary tumor was: the oropharynx (108 cases), the hypopharynx (88 cases), the oral cavity (44 cases), the larynx (20 cases), the rhinopharynx (6 cases) and the cervical oesophagus (1 case). Endoscopic procedure with biopsy was performed for all the patients. Histologic examination revealed an invasive squamous cell carcinoma in all the cases. The complete check up included a ultrasound scan of the liver and a chest X-ray for all the patients.

RESULTS

Ultrasound scan of the liver revealed one or several metastases in 4 cases (1.5%). The primary tumor was hypopharyngeal in 3 cases (2 stages III, 1 stage IV) and oropharyngeal in 1 case (stage III). In three cases, carcinoma was poorly differentiated. Ultrasound scan of the liver was doubtful for 8 patients (3%). The primary tumor was oropharyngeal in 6 cases (1 stage I, 3 stages III, 2 stages IV), laryngeal in 1 case (stage III) and hypopharyngeal in case (stage IV). In six cases carcinoma was well differentiated. All the complementary examinations concluded to a benign liver disease, with a mean diagnosis delay of 4 weeks for the 8 patients. The mean follow-up duration of the 8 patients was 22 months (range 9 to 42 months). None presented any metastases during the follow up.

CONCLUSION

Our results compared with those of the literature revealed that ultrasound scan of the liver is a few specific examination which may be recommended for hypopharyngeal tumors, or for a large cervical adenopathy (N2 or N3), a poor differentiated tumor wherever the site of the primary tumor is.

[An experimental study on bone marrow purging in vitro for patients with chronic myelogenous leukemia]

OBJECTIVE

To investigate the effect of IL-2, IFN and bcr-abl AS-ODN on bone marrow purging in vitro for patients with chronic myelogenous leukemia (CML).

METHODS

By amplifying in vitro clone forming culture, and purging the bone marrow of 5 CML patients through different combined use of IL-2, IFN and bcr-abl AS-ODN, we compared the effects of 4 combined regimens.

RESULTS

It was found that the suppressive effects of the 4th regimen combining IL-2 (800 U/ml), IFN (800 u/ml) and bcr-abl AS-ODN (30 micrograms/ml) on leukemia cell clone forming unit (CFU) were significantly different from the suppressive effects of the other 3 regimens (P < 0.01). With the use of the 4th regimen, the GM-CFU and L-CFU survival rates were 26.91% and 3.49% respectively (P < 0.01).

CONCLUSION

The combined regimen of IL-2 (800 U/ml), IFN (800 u/ml) and bcr-abl AS-ODN (30 micrograms/ml) has good effect on selective CML bone marrow purging in vitro and can be used in clinical purging of CML bone marrow.

[Effect of radix angelicae sinensis decoction for supplementing blood on inhibiting the increase of endothelial cell monolayer permeability induced by hypoosmotic solution]

OBJECTIVE

To study effect of radix Angelicae sinensis decoction for supplementing blood (RASDSB) on inhibiting the increase of endothelial cell monolayer permeability induced by hypoosmotic solution.

METHODS

The endothelial cells isolated from newborn bovine aorta were cultured on polycarbonate microporous filter membrane to develop compact endothelial monolayer. Fluid filtration coefficient (Kf), filtration volume (Jv) and osmotic reflective coefficient (sigma) to protein of the endothelial monolayer were measured treated by hypoosmotic solution (changing concentration of serum in M199 solution from 20% to 2%) for 120 min or by hypoosmotic solution containing 10(-4) g x ml(-1) RASDSB for 120 min after perfused Hanks balanced salt solution containing 5 g x L(-1) albumin.

RESULTS

Kf and Jv of the endothelial monolayer treated by hypoosmotic solution increased and sigma of that decreased. RASDSB could inhibit above-mentioned change. Morphological analysis demonstrated that RASDSB could inhibit widening of intercellular distance and enlargement of cellular area in the endothelial monolayer induced by hypoosmolality.

CONCLUSION

Hypoosmotic solution could increase endothelial cell monolayer permeability and RASDSB could inhibit the increase.

[High level expression and purification of Cysticercosis cellulose annexin32 in Escherichia coli]

In previous work, the cDNA encoding Cysticercus cellulose annexin32 has been cloned. With PCR method, two different restriction Sites were added to each end of the cDNA respectively. Then, the cDNA was inserted into prokaryotic expression vector pJLA-503. After inducing, most foreign protein was expressed in soluble form, which was up to 35% of the total protein of the bacteria. Subsequently, the recombinant Annexin32 was purified with (NH4)2SO4 stepwise precipitation, DEAE-Sepharose FF and Sephacryl S-200 HR chromatography. The final pure protein can been shown as a single band in SDS-PAGE, and the biological activity was verified by Western blot and anticoagulation activity assay.

Resensitization of blood pressure response to mu-opioid peptide agonists after acute desensitization

IV administration of mu-opioid peptide agonists (DAMGO, DALDA, and [Dmt(1)]DALDA) results in a transient, naloxone-sensitive, increase in blood pressure in awake sheep. Despite significant differences in pharmacokinetics, these blood pressure responses all last < 15 min. The lack of correlation between half-life and duration of action suggested rapid desensitization. When a second dose of the same agonist was repeated 30 min later, the response was completely abolished. An increase in blood pressure and rapid desensitization was also observed with the kappa-opioid agonist (U50488H), whereas delta-agonists (DPDPE and DELT) had no effect on blood pressure. The response to DAMGO was abolished after prior exposure to DAMGO or DALDA, but there was no evidence of cross-desensitization between mu and delta, or mu and kappa, opioid agonists. Full resensitization of the blood pressure response occurred by 4 h for DAMGO (t(1/2) = 15 min) and by 48 h for [Dmt(1)]DALDA (t(1/2) = 1.8 h). These data support our hypothesis that the transient nature of the blood pressure response to mu-opioid agonists is caused by rapid desensitization and suggest that the rate of resensitization is dependent on the pharmacokinetics of the agonist.

The Arabidopsis immutans mutation affects plastid differentiation and the morphogenesis of white and green sectors in variegated plants

The immutans (im) variegation mutant of Arabidopsis has green and white leaf sectors due to the action of a nuclear recessive gene, IMMUTANS (IM). This gene encodes the IM protein, which is a chloroplast homolog of the mitochondrial alternative oxidase. Because the white sectors of im accumulate the noncolored carotenoid, phytoene, IM likely serves as a redox component in phytoene desaturation. In this paper, we show that IM has a global impact on plant growth and development and is required for the differentiation of multiple plastid types, including chloroplasts, amyloplasts, and etioplasts. IM promoter activity and IM mRNAs are also expressed ubiquitously in Arabidopsis. IM transcript levels correlate with carotenoid accumulation in some, but not all, tissues. This suggests that IM function is not limited to carotenogenesis. Leaf anatomy is radically altered in the green and white sectors of im: Mesophyll cell sizes are dramatically enlarged in the green sectors and palisade cells fail to expand in the white sectors. The green im sectors also have significantly higher than normal rates of O(2) evolution and elevated chlorophyll a/b ratios, typical of those found in "sun" leaves. We conclude that the changes in structure and photosynthetic function of the green leaf sectors are part of an adaptive mechanism that attempts to compensate for a lack of photosynthesis in the white leaf sectors, while maximizing the ability of the plant to avoid photodamage.

Imaging and visualization of 3-D cardiac electric activity

Noninvasive imaging of cardiac electric activity is of importance for better understanding the underlying mechanisms and for aiding clinical diagnosis and intervention of cardiac abnormalities. We propose to image the three-dimensional (3-D) cardiac bioelectric source distribution from body-surface electrocardiograms. Cardiac electrical sources were modeled by a current dipole distribution throughout the entire myocardium, and estimated by using the Laplacian weighted minimum norm (LWMN) algorithm from body-surface potentials. The estimated inverse solution of the current distribution was further improved by using a recursive weighting strategy for localized sources, such as origins of cardiac arrhythmias. Computer simulations were conducted to test the feasibility of the proposed approach by using a 3-D ventricle model embedded in a realistically shaped torso model. The boundary element method was used to solve the forward problem from assumed cardiac sources to the body-surface potentials. Two testing dipoles were placed in the left and right ventricles, simulating the early activation associated with ventricular arrhythmias. The LWMN inverse solution showed an equivalent source distribution over the entity of both ventricles, with spread areas of activity overlying the positions of the testing dipoles. The sharpened inverse image provides well-localized focal sources near the testing dipole positions. In summary, the present computer simulation suggests that the proposed 3-D cardiac current source imaging and localization approach appears to be a promising candidate for localizing and imaging sites of origins of cardiac activation.

[Analysis of association between gene polymorphisms of microsomal epoxide hydrolase (EPHX1) and infant birthweight]

We investigated association between genetic polymorphisms of EPHX1 in mother and infant birthweight. Data of 342 female workers were collected in textile mill. A total of 342 mothers were genotyped for the His139Arg polymorphism of EPHX1 by a polymerase chain reaction-restriction fragment length polymorphism assay. Using multiple linear regression models, we estimated the adjusted association between polymorphisms of EPHX1 and birthweight, with adjusted for potential confounders. We found that polymorphisms of EPHX1 were closely associated with reduced birthweight (beta +/- SE = -149 g +/- 56, P = 0.0083) after adjustment for major cofounders. In subgroup of passive smoking analysis, the polymorphisms of EPHX1 were highly associted with birthweight for those with passive smoking (beta +/- SE = -234 g +/- 88, P = 0.0088); The significant association of EPHX1 polymorphisms with reduced birthweight were showed for those with working stress (beta +/- SE = -157 g +/- 59, P = 0.0079). Our data provide polymorphisms of EPHX1 in mothers were significant association with birthweight of their infant, and showed gene-environmental interaction in relation to birthweight.