Clinical presentation, disease course, and outcome of COVID-19 in hospitalized patients with and without pre-existing cardiac disease: a cohort study across 18 countries

AIMS

Patients with cardiac disease are considered high risk for poor outcomes following hospitalization with COVID-19. The primary aim of this study was to evaluate heterogeneity in associations between various heart disease subtypes and in-hospital mortality.

METHODS AND RESULTS

We used data from the CAPACITY-COVID registry and LEOSS study. Multivariable Poisson regression models were fitted to assess the association between different types of pre-existing heart disease and in-hospital mortality. A total of 16 511 patients with COVID-19 were included (21.1% aged 66-75 years; 40.2% female) and 31.5% had a history of heart disease. Patients with heart disease were older, predominantly male, and often had other comorbid conditions when compared with those without. Mortality was higher in patients with cardiac disease (29.7%; n = 1545 vs. 15.9%; n = 1797). However, following multivariable adjustment, this difference was not significant [adjusted risk ratio (aRR) 1.08, 95% confidence interval (CI) 1.02-1.15; P = 0.12 (corrected for multiple testing)]. Associations with in-hospital mortality by heart disease subtypes differed considerably, with the strongest association for heart failure (aRR 1.19, 95% CI 1.10-1.30; P < 0.018) particularly for severe (New York Heart Association class III/IV) heart failure (aRR 1.41, 95% CI 1.20-1.64; P < 0.018). None of the other heart disease subtypes, including ischaemic heart disease, remained significant after multivariable adjustment. Serious cardiac complications were diagnosed in <1% of patients.

CONCLUSION

Considerable heterogeneity exists in the strength of association between heart disease subtypes and in-hospital mortality. Of all patients with heart disease, those with heart failure are at greatest risk of death when hospitalized with COVID-19. Serious cardiac complications are rare during hospitalization.

Development of Indirect Immunofluorescence Technique for the Identification of MRC5 Working Seed Cell

Diploid and continuous cell lines are used to propagate viral vaccines. At Human Viral Vaccine Department of Razi Vaccine and Serum Research Institute, MRC5 diploid cell is used for the development of live attenuated measles, mumps, rubella, and three types of poliovirus vaccines. Additionally, three continuous cell lines (i.e., RK13, HeLa, and Vero) are applied in quality control tests. Accordingly, cell cross-contamination can occur at cell culture labs, hence controlling the identity and specificity of cells is essential. Indirect immunofluorescence is a sensitive, specific, and simple test for cell identification. The present study was designed to develop the in-house indirect immunofluorescence test (IIF) as follows: homemade polyclonal anti-MRC5 serum was prepared in rabbits, and cross-reactive antibodies to RK13, HeLa, and Vero cells were eliminated. The diploid and continuous cell lines were fixed on Teflon slide using cold methanol and acetone. The reproducibility of the in-house IIF test was evaluated using the agreement Kappa test. The purity of the three batches of MRC5 working seed cell at Human Viral Vaccine Department of Razi institute was verified using IIF and no contamination with continuous cell lines was detected.

IFPA meeting 2015 workshop report IV: placenta and obesity; stem cells of the feto-maternal interface; placental immunobiology and infection

Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialised topics. At the 2015 IFPA annual meeting there were 12 themed workshops, three of which are summarized in this report. These workshops related to various aspects of placental biology and collectively covered areas of obesity and the placenta, stem cells of the feto-maternal interface, and placental immunobiology and infection.

Synthesis of N, N-dimethyl N-ethyl Chitosan as a Carrier for Oral Delivery of Peptide Drugs

N, N-dimethyl N-ethyl chitosan (DMEC), a quanternized derivative of chitosan was synthesized based on a modified two-step method via a 22 factorial design to optimize the preparative conditions. The degree of deacetylation of the starting chitosan was determined by FTIR and NMR methods and was 95%. In the first step of the synthesis, mono-ethyl chitosan was prepared by introducing an ethyl group onto the amine group of chitosan via a Schiff base and in the next step methyl iodide was added to produce DMEC which was water soluble in a pH range of 4-8. The DMEC polymers with different degrees of quaternization were obtained and fully characterized using FTIR and 1H-NMR spectroscopic methods. Based on 1H-NMR calculations, the degree of quaternization was 52% by optimizing the two-step process.

Optimized Synthesis and Characterization of N-Triethyl Chitosan

Chitosan exhibits poor solubility at pH values above 6 which prevents its enhancing effects at drugs absorption of sites. In the present work, N-triethylated chitosan (TEC) was prepared based on a modified one-step process via a 22 factorial design to optimize the preparative conditions. TEC polymer with different degree of quaternization for pharmacological and pharmaceutical experiments was achieved. Ethyl iodide and sodium hydroxide concentrations were chosen as independent variables. The degree of deacetylation of the starting chitosan was predetermined by pH-metric titration, infrared, and NMR methods. TEC chloride was fully characterized using FTIR and 1H-NMR spectroscopies. Based on NMR calculations, a high degree of quaternization was achieved through the optimized one-step process. These highly N-triethylated chitosan chlorides were soluble in water at room temperature.

N,N-Diethyl N-Methyl Chitosan as an Enhancing Agent for Colon Drug Delivery

Chitosan exhibits poor solubility above pH 6 which prevents absorption at treatment sites in the colon. pH titrations and infrared methods were used to determine the degree of deacetylation of the starting chitosan. In the present work, N,N-diethyl N-methyl chitosan (DEMC) was synthesized based on a modified two-step process via a 22 factorial design to optimize the preparative conditions. DEMC chloride was characterized using FTIR and 1H NMR spectroscopy. For pharmacological and pharmaceutical applications, DEMC needs to have specific degrees of quaternization. Based on the 1H NMR data, a high degree of quaternization was achieved by the two-step process. The N-diethyl methyl chitosan chlorides were completely soluble in water at room temperature. Sodium fluorescein and brilliant blue were used as model reagents for in vitro colonic absorption studies. These studies show a significant increase in the absorption of sodium fluorescein and brilliant blue in the presence of DEMC in comparison with normal chitosan. DEMC with positive charge is able to interact with tight junctions of colon epithelial cells and hence increased the permeability of sodium fluorescein and brilliant blue across the tight junctions. These investigations demonstrated that the DEMC derivative of chitosan could have a significant effect on colonic drug absorption.

Turn-on fluorescent chemosensor for determination of lutetium ion

A turn-on fluorescent chemosensor is introduced for the detection of Lu(3+) ion using N-[3-methyl]-2-[pyridine-2-amido] phenyl] pyridine-2-carboxamide (L) molecule. Fluorescent emission intensity of L enhances after binding to Lu(3+) ions in ethanol-water solution (1:9, v/v). The observed enhancement is the result of a strong covalent binding between Lu(3+) ion and L (the binding constant value is 2.0×10(6) mol(-1) L). The proposed optical chemosensor can be applied for the analysis of Lu(3+) ion in a linear range of 3.3×10(-7) to 1.0×10(-5) mol L(-1). The limit of detection was obtained 8.6×10(-7) mol L(-1). The probe exhibits high selectivity toward Lu(3+) ion in comparison with common metal ions. The proposed fluorescent chemosensor was successfully used in the determination of Lu(3+) ion in some water samples.

Predictors of delayed and no-reflow as recognized with Thrombolysis in Myocardial Infarction [TIMI] flow grade following Primary Percutaneous Coronary Angioplasty

Background: Initial percutaneous coronary interference (PCI) is still connected by a noticeable incidence of suboptimal coronary flow thrombolysis in infarction of myocardial (TIMI). The predictors of slow and no-reflow in cases that supported initial PCI in our institute was searched for and the relationship of these parameters with major adverse cardiovascular effects (MACE) was assessed. Material and Method: 397 patients with AMI displaying in 24 hours of the sign opening were retrospectively enrolled and underwent primary PCI between March 2006 and March 2012. Demographic, clinical, and procedural data were retrieved from our institutional databank. The baseline and post-PCI flow of blood in the revascularized artery was ranked based on the TIMI grading method. The follow-up visits were performed after one, six and twelve month from hospitalization. All the mortalities and complications were recorded within this period for evaluate the MACE. Results: The frequency of diabetes mellitus and renal failure were importantly larger in cases with a TIMI flow of 0-1 (p=0.03 & p=.01, respectively). Similarly, level of serum creatine were importantly larger in cases with a TIMI flow of 0-1. The predictors for TIMI flow included that utilize of Adenosin or Integrilin, diabetes mellitus, POIT, long tubular lesion, and injury at LAD territory. The incidence of MACE was significantly higher in patients with a TIMI flow of 0-1 (P=0.001) and the survival in this subgroup was significantly poorer (Hazard ratio=4.96; P<0.001). Conclusion: A low TIMI flow is accompanied by a poorer survival and a higher MACE and is influenced by some clinical and vascular characteristics.

Facile, novel and efficient synthesis of new pyrazolo[3,4-b]pyridine products from condensation of pyrazole-5-amine derivatives and activated carbonyl groups

A novel, simple and efficient route for the synthesis of new fused pyrazolo[3,4-b]pyridines is described.

Novel isolation strategy to deliver pure fetal-origin and maternal-origin mesenchymal stem cell (MSC) populations from human term placenta

The placenta is an abundant source of mesenchymal stem/stromal cells (MSC). Although presumed of translationally-advantageous fetal origin, the literature instead suggests a high incidence of either contaminating or pure maternal MSC. Despite definitional criteria that MSC are CD34-, increasing evidence suggests that fetal MSC may be CD34 positive in vivo. We flow sorted term placental digests based on CD34+ expression and exploited differential culture media to isolate separately pure fetal and maternal MSC populations. This method has considerable translational implications, in particular to clinical trials underway with "placental" MSC of uncertain or decidual origin.

Gas barrier and mechanical properties of crosslinked ethylene vinyl acetate nanocomposites

In this research, the effects of crosslinking agent and clay content on the morphology, barrier and mechanical properties of ethylene vinyl acetate-organoclay nanocomposites prepared by solution method were studied. Dicumyl peroxide has been used as crosslinking agent. The morphology of the prepared nanocomposites was investigated using wide-angle X-ray diffraction and transmission electron microscopy. Wide-angle X-ray diffraction and transmission electron microscopyindicated that the prepared nanocomposites had predominantly intercalated morphologies. The obtained results of permeability tests showed that the permeability of ethylene vinyl acetate films dramatically decreases with addition of organoclay and dicumyl peroxide. Mechanical tests showed that tensile modulus and tensile strength of ethylene vinyl acetate increase with addition of organoclay. Furthermore, the mechanical properties of ethylene vinyl acetate nanocomposites significantly improved in presence of crosslinking agent (dicumyl peroxide).

Assessment of endogenous androgen levels in meat, liver and testis of Iranian native cross-breed male sheep and bull by gas chromatography-mass spectrometry

Androgenic steroids always exist in different animal tissues at trace level, with significant numbers of interfering compounds, which makes their determination difficult. To solve some of the problems in quantification of the natural steroids in those tissues, a new GC-MS method was developed in this study. By using a surrogate analyte approach, which was developed in the authors' previous studies, and extensive sample preparation procedure, which successfully eliminates many of the interfering compounds and resulting in a cleaner extract, accuracy, precision, sensitivity and selectivity of the method for the determination of steroids in complex matrices such as meat, liver and testis were improved. By aid of this method, the levels of androgens in different tissues of Iranian native cross-breed bulls and male sheep were determined. According to the results obtained in the present study, although the androgenic profile (contents and ratios of precursors and metabolites to the main hormones) is similar between the same tissues of both animals, the total androgenic content of each tissue is higher in the bull than the same tissue in male sheep. In addition, in both animals higher amount of androgens were found in liver in comparison with meat and testis.

Early spontaneous immortalization and loss of plasticity of rabbit bone marrow mesenchymal stem cells

OBJECTIVES

Bone marrow-derived mesenchymal stem cells (BM-MSC) have been widely used for cell therapy and tissue engineering purposes. However, there are still controversies concerning safety of application of these cells after in vitro expansion. Therefore, we aimed to investigate the characteristics of rabbit BM-MSC during long-term culture.

MATERIALS AND METHODS

In this study, we have examined growth kinetics, morphological changes, differentiation potential and chromosomal abnormalities, as well as tumour formation potential of rabbit BM-MSC in long-term culture.

RESULTS AND CONCLUSION

We found that shortly after isolation, proliferation rate of rabbit BM-MSC decreases until they enter a dormant phase. During this period of quiescence, the cells are large and multinucleate. After some weeks of dormancy we found that several small mononuclear cells originated from each large multinucleate cell. These newly formed cells proliferated rapidly but had inferior differentiation potential. Although they were immortal, they did not have the capability for tumour formation in soft agar assay or in nude mice. This is the first report of spontaneous, non-tumorigenic immortalization of BM-MSC in rabbits. The phenomenon raises more concern for meticulous monitoring and quality control for using rabbit BM-MSC in cell-based therapies and tissue engineering experiments.

Synthesis and cloxacillin antimicrobial enhancement of 2-methylsulfonylimidazolyl-1,4-dihydropyridine derivatives

BACKGROUND AND THE PURPOSE OF THE STUDY

Hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) has been a major problem worldwide in chemotherapy of infection disease. This study was designed to assess the enhancing effects of a new group of dihydropyridine-3,5dicarboxamides, in combination with cloxacillin with distinctly different mechanisms of action against MRSAs.

MATERIAL AND METHODS

Dihydropyridine-3,5-dicarboxamides with 2-methylsulfonylimidazole at 4 position 6a-k were synthesized by the reaction of corresponding aldehyde 5 with different N-aryl acetoacetamides 3 in the presence of ammonium hydroxide. Agar disc diffusion method was used to determine the antibacterial and potentiating activity of different synthetic compounds in the presence and absence of cloxacillin to evaluate their activity as modulators of multidrugresistant (MDR).

RESULTS AND MAJOR CONCLUSION

The antibacterial effect of cloxacillin was enhanced by compounds 6g and 6h against cloxacillin-resistant strains (MRSA(1) and MRSA(2)). The potentiation was found 1 2 to be statistically significant (p<0.01). Compound 6g at concentration of 1000 µg/disc, caused a 329 percent potentiation of the activity of cloxacillin against MRSA(1).

Synthesis and cytotoxic activity of some 2-amino-4-aryl-3-cyano-7-(dimethylamino)-4H-chromenes

A series of 2-amino-4-aryl-3-cyano-7- (dimethylamino)-4H-chromenes was synthesized by condensation of 3- (dimethylamino) phenol, an aromatic aldehyde and malonitrile in ethanol containing piperidine. The assignments of the structure of all synthesized compounds were based on spectral data (IR, Mass and(1)H NMR). The cytotoxic activities of the synthesized compounds against six human tumor cell lines were determined by MTT assay. Several compounds showed significant cytotoxic activity.

Effects of novel antituberculosis agents on OmpF channel activity

Nanopore forming proteins spanning the outer membrane mediate in the diffusion of hydrophilic chemicals through the hydrophobic bacterial cell wall. In this study, the effects of two novel anti-TB derivatives, ethyl alpha-[5-(5-nitro-2-thienyl)-1,3,4-thiadiazole-2-ylthio] acetates and propyl alpha-[5-(5-nitro-2-thienyl)-1,3,4-thiadiazole-2-ylthio] acetates, on OmpF channel reconstituted in artificial bilayers were evaluated by voltage clamp technique. Surprisingly, ethyl derivative (MIC > or = 6.75 microg/ml) showed no effects on OmpF channel activity but the propyl derivative (MIC=0.39 microg/ml) reduced the channel conductance considerably and changed the gating pattern of the channel. The findings obtained here at molecular level, might shed light on better understanding of the actual mechanism(s) by which the novel anti-TB agents permeate through the cell wall of the Mycobacterium tuberculosis.

Antigen-specific lymphocyte proliferation assay and virus neutralization test for measurement of measles-specific immunity in 15-19 years old high school students in Tehran, Iran

Limited information is available concerning the role of measles-specific cell mediated immunity as a correlate of long-term protection from measles infection. Although serological responses are determined in epidemiological studies and high antibody titer is a good indicator of protection, the role of Cell-Mediated Immunity (CMI) has to be defined more clearly. In this study, Lymphocyte Proliferation (LP) and Viral Neutralization Test (VNT) were used in order to measure measles-specific cellular and humoral immune responses of 100 high school students in Tehran. From total number of subjects studied, 33 were girls and 67 were boys and all were in good health. Of these, 77 had protective neutralizing measles antibody titers and 23 did not have such titer. The results of LP showed that 89 subjects had protective cellular immune responses and 11 did not. A quantitative relationship between humoral and cellular immune responses was not observed. These findings suggest that measles-specific protective CMI is measurable for longer time in comparison to humoral immunity. These data suggest that LP responses may be better sustained than antibody titers in some children.

Evaluation of anticancer effects of newly synthesized dihydropyridine derivatives in comparison to verapamil and doxorubicin on T47D parental and resistant cell lines in vitro

Failure of current anticancer drugs mandates screening for new compounds of synthetic or biological origin to be used in cancer therapy. Multidrug resistance (MDR) is one of the main obstacles in the chemotherapy of cancer. Efflux of cytotoxic agents mediated by P-glycoprotein (P-gp or MDR1) is believed to be an important mechanism of multidrug resistance. Therefore, we decided to investigate the antiproliferative effects of seven newly synthesized 1,4-dihydropyridine (DHP) derivatives in comparison to verapamil (VP) and doxorubicin (DOX) on human breast cancer T47D cells and its MDR1 overexpressed and moderately resistant cells (RS cells) using MTT cytotoxicity assay. We also examined the effects of these compounds on cytotoxicity of DOX in these two cell types. The cytotoxicity assays using MTT showed that most of the tested new DHP derivatives and VP at 10 microM concentration had varying levels of toxicity on both T47D and RS cells. The toxicity was mostly in the range of 10-25%. However, the cytotoxicity of these DHP derivatives, similar to VP, was significantly less than DOX when comparing IC(50) values. Furthermore, these compounds in general had relatively more cytotoxicity on T47D vs RS cells at 10-microM concentration. Among new DHPs, compounds 7a (3,5-dibenzoyl-4-(2-methylthiazol-4-yl)-1,4-dihydro-2,6-dimethylpyridine) and 7d (3,5-diacetyl-4-[2-(2-chlorophenyl)thiazol-4-yl)]-1,4-dihydro-2,6-dimethylpyridine) showed noticeable potentiation of DOX cytotoxicity (reduction of DOX IC(50)) compared to DOX alone in both cells, particularly in RS cells. This effect was similar to that of VP, a known prototype of MDR1 reversal agent. In other words, compounds 7a and 7d resensitized RS cells to DOX or reversed their resistance. Results indicate that compound 7d exerts highest effect on RS cells. Therefore, these two newly synthesized DHP derivatives, compounds 7a and 7d, are promising as potential new MDR1 reversal agents and should be further studied on other highly resistant cells due to MDR1 overexpression and with further molecular investigation.

The Application of Shannon's Measure of Information for a Complex Chemical System

Information theory and, specifically, Shannon's measure of information is used to compare the interaction parameters (beta) in regular solution theory (RST) and Ingram's model for the mixture of cetyltrimethylammonium bromide (CTAB) and Triton X-100 (TX100). Results show that beta values from regular solution theory are more accurate than those of Ingram's model. Additionally, the procedure applied in this paper for the calculation of uncertainties in the continuous case, prevents difficulties concerning differential entropy.

Extradural spinal cord and intraabdominal ganglioneuroblastoma

We report a rare case of a giant extradural and intraabdominal ganglioneuroblastoma in a young Malay girl who presented to a paediatrician initially at 5 days of life with a palpable abdominal mass. Unfortunately, the parents refused any form of surgical intervention until the child was 3 years old. She subsequently underwent vascular embolisation followed by the removal of this large tumour both via the abdomen and through a laminectomy approach and subsequently refused chemotherapy. The c-myc amplication in this patient was absent and there were no chromosomal aberrations, During the 2 year folow-up the patient remained well, and ambulatory with no tumour recurrence.

Preparation of [61Cu]-2-acetylpyridine thiosemicarbazone complex as a possible PET tracer for malignancies

Due to the interesting anti-proliferative properties of copper-thiosemicarbazone complexes, the production of a (61)Cu-labeled thiosemicarbazone, i.e. 2-acetylpyridine thiosemicarbazone (APTS) was investigated. Copper-61 (T(1/2)=3.33 h) was produced via the (64)Zn(p,alpha)(61)Cu nuclear reaction using a natural zinc target irradiated with 22 MeV protons for 500 microAh. The (61)Cu was separated from the irradiated target material by a two-step method and converted to acetate; this yielded a final activity of 222 GBq (6.0 Ci), with a radiochemical yield of >95%. The (61)Cu-acetate was mixed with 2-acetylpyridine thiosemicarbazone for 30 min at room temperature to yield [(61)Cu]APTS with a radiochemical yield of more than 80%. Colorimetric methods showed that residual chemical impurities in the product were below the accepted limits. Radio thin layer chromatography (RTLC) showed a radiochemical purity of more than 99% after C(18) column chromatography. A specific activity of about 370-740 MBq/mmol (10-20 Ci/mmol) was obtained. The stability of the final product was checked in the absence and presence of human serum at 37 degrees C for up to 3 h. The partition coefficient of the final complex was also determined.

Pre-column derivatization of rofecoxib for determination in serum by HPLC

An HPLC method for determination of rofecoxib in human serum is presented. The method is based on pre-column derivatization of analyte to a phenanthrene derivative of the drug. Rofecoxib and the internal standard were extracted from serum using liquid-liquid extraction. Upon exposure to UV light, the drug was found to undergo a photocyclization reaction, giving a species with high absorbance. Validation of the method has been studied in the concentration range 10-500 ng ml(-1).

Synthesis of [75Se]5-ethoxycarbonyl-4-methyl-1,2,3-selenadiazole

Selenium-75 (t1/2 = 120.4d; 100% EC) was prepared in no-carrier-added form by 22MeV proton-bombardment of natural arsenic(III) oxide powder held in a copper-aluminum drawer target (highest yield, 35 microCi/microAh; maximum current, 6 microA), followed by oxidation to [75Se]selenium(IV) oxide. No-carrier-added [75Se]5-ethoxycarbonyl-4-methyl-1,2,3-selenadiazole was prepared in one step from ethylacetoacetate semicarbazone with [75Se]selenium(IV) oxide in glacial acetic acid at 50 degrees C. Column chromatography of the final solution afforded the desired labeled compound in 30% yield and greater than 98% radiochemical purity.

Application of a simple and sensitive GC-MS method for determination of morphine in the hair of opium abusers

Thirty hair samples were collected from male opioid abusers for whom the presence of morphine in their urine samples was confirmed by thin layer chromatography (TLC). The hair samples were decontaminated by washing with isopropanol, deionized water, and isopropanol, dried at room temperature, and cut into small pieces. Samples of the latter (30 mg ) were digested by incubation in a mixture of methanol-trifluoroacetic acid (9:1) for 18 h at 45 degrees C and sonicated to improve the extraction process. The methanolic phase was evaporated to dryness under a stream of nitrogen at 50 degrees C. The sample was derivatized by addition of N-methyl- N-trimethylsilyltrifluoroacetamide (MSTFA) and 1% trimethyliodosilane (TMIS) at 70 degrees C for 20 min, with sonication. Derivatized samples (1 microL) were injected into a gas chromatograph-mass spectrometer (GC-MS) system fitted with a capillary column; the Finnigan MS was operated in SIM mode. Naltrexone was used as internal standard (IS). The masses of the ions selected for morphine and naltrexone were 429 and 557, respectively. The limit of quantitation was set at 0.03 ng mg(-1) hair. By using the above procedure we detected morphine in all the samples examined, in the concentration range 0.26-10.31 ng mg(-1 )hair.

Synthesis and calcium antagonist activity of 1,4-dihydropyridines containing phenylaminoimidazolyl substituents

Alkyl ester analogues of nifedipine, in which the ortho-nitrophenyl group at position 4 is replaced by 2-methylthio-1-phenylamino-5-imidazolyl substituent, were synthesized and evaluated as calcium-channel antagonists using the high K(+) contraction of guinea-pig ileal longitudinal smooth muscle. The results for the symmetrical esters showed that in the series of alkyl esters increasing the length of methylene chain in C-3 and C-5 ester substituents for more than two methylene units decreases activity. In the phenylalkyl ester series increasing the length of methylene chain also decreases activity. The results demonstrate that most of the compounds had similar activity to the reference drug nifedipine. In addition, two compounds, 5b and 5f were more active than the nifedipine.

Synthesis and Evaluation of Pharmacological Activities of 3, 5-Dialkyl 1, 4-Dihydro-2, 6-Dimethyl-4-Nitroimidazole-3, 5-Pyridine Dicarboxylates

New analogues of nifedipine, in which the 2-nitrophenyl group at position 4 is replaced by a 1-methyl-5-nitro-2-imidazolyl substituent, were synthesized. The symmetrical dialkyl 1, 4-dihydro-2, 6-dimethyl-4-(1-methyl-5-nitro-2-imidazolyl)-3, 5-pyridinedicarboxylates were prepared by a classical Hantzsch condensation. The asymmetrical analogues were synthesized using a procedure reported by Iwanami that involved the condensation of alkylacetoacetate with methyl-, ethyl- or isopropyl3-aminocrotonate and 1-methyl-5-nitroimidazole-2-carboxaldehyde. Calcium channel antagonist activities were determined in vitro using a guinea pig ileum longitudinal smooth muscle (GPILSM)assay. Many compounds exhibited superior, or equipotent, calcium antagonist activity (IC(50) = 10(-10) to 10(-13) M range) relative to the reference drug nifedipine (IC(50) = 1.09 +/- 0.12 x 10(-11) M). Antinociceptive effects of some compounds were evaluated by the mouse tail-flick assay in vivo. Results demonstrate that some of the compounds were active as an antinociceptive.