Reduced LA active EF (booster pump function) assessed by speckle tracking echocardiography independently predicts the risk of new-onset AF, suggesting a stronger association between LA functional remodelling and AF than between LA size and AF.

The continuous usage of pyrethroids against insects has provoked the emergence of insecticide resistance that has become a major obstacle to disease vector control. The knockdown resistance (kdr) voltage-gated sodium channel gene is regarded as a key to understanding the mechanism of resistance to pyrethroids. The main purpose of this study is to identify point mutations in the sodium channel gene associated with deltamethrin resistance in Aedes aegypti. Two mutations in the IIS6 domain of the channel, S989P and V1016G, were identified as possible candidates responsible for the emergence of deltamethrin resistance in Ae. aegypti Khu Bua strain. As S989P and V1016G mutations are located within the IIS5-S6 loop and IIS6 near the ion filter and binding site, these mutations might enhance pyrethroid resistance. Allelic variation in the sodium channel gene is thought to be one of the principal molecular mechanisms regulating pyrethroid resistance in mosquitoes.

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SUMMARY1. Rundown of L-type calcium channels was studied in inside-out patches made from single isolated rabbit ventricular myocytes, using barium as the charge carrier.2. In the cell-attached patches single-channel activity was stable for more than 15 min after the patch pipette sealed. f-Receptor stimulation by isoprenaline caused a characteristic increase in opening probability and the appearance of prolonged openings. When the patch was excised to the inside-out configuration and exposed to a simple ionic solution, channel activity disappeared within 1-2 min and never reappeared spontaneously. 3. After rundown of L-type channel activity in the excised patch, exposure of the inside face of the patch to MgATP and the catalytic subunit of the cyclic AMPdependent protein kinase (PKAc) resulted in recovery of Ca21 channel activity. Under these conditions channel activity could be even greater than under control cell-attached conditions, resembling channel activity after exposure to isoprenaline.

LA function, particularly LA active relaxation and contraction, was lower in PAF patients than in subjects with sinus rhythm, regardless of LA size and age. LA functional impairment was observed regardless of hypertension before LA enlargement in patients with PAF. Reduced LA function, as assessed by VVI, is an important feature of AF as well as LA structure.

The nth and nei genes of Escherichia coli affect the production of endonuclease III and endonuclease VIII, respectively, glycosylases/apurinic lyases that attack DNA damaged by oxidizing agents. Here, we provide evidence that oxidative lethal lesions are repaired by both endonuclease III and endonuclease VIII and that spontaneous mutagenic lesions are repaired mainly by endonuclease III.Endonuclease III (endo III) has an apurinic (AP) lyase activity at apurinic/apyrimidinic sites in DNA and has a DNA glycosylase activity that excises oxidative pyrimidine residues such as thymine glycol (2,5,8,11,14). Escherichia coli mutants defective in endo III (nth mutants) were found to exhibit normal resistance to DNA-damaging agents such as hydrogen peroxide and X rays (7). Since thymine glycol has been shown to be a lethal lesion in vitro (6, 12, 13) and in vivo (10,15,17), and a mutagenic lesion in vitro (4), the possibility existed that alternative pathways for the repair of these damages are present in E. coli. The availability of nth mutants facilitated the identification of a distinct enzyme with similar properties, designated endonuclease VIII (endo VIII) (16). Endo VIII releases modified pyrimidine bases and possesses DNA glycosylase and AP lyase activities. The gene coding for endo VIII was named nei.To understand the role of thymine glycol and modified pyrimidine bases in lethality and mutagenesis, it is important to determine the properties of nei and nth single mutation and nei nth double mutation. We report here the cloning and sequencing of the nei ϩ gene, coding for endo VIII, and the use of the cloned gene to construct an endo VIII-defective mutant of E. coli.Isolation of nei and nth plasmids. The structural gene for endo III (nth) of E. coli was assigned on Clark-Carbon plasmid pLC3-6, which contains DNA fragments at 36 min on the linkage map (18). Therefore, using pLC3-6, a 5-kb EcoRI-KpnI fragment including the nth gene was ligated on pTZ18R, named pTZ18Rnth. The sequence of a portion of this fragment agreed perfectly with that of the nth gene (data not shown).The DNA sequence of the structural gene coding for endo VIII (nei) of E. coli appears in the GenBank database under accession no. U38616. We have previously cloned a 20-kb DNA fragment, named pKY1, containing the structural gene coding for photolyase (phr) of E. coli, which is mapped at 16 min (22). Part of the detailed physical map of pKY1 looks like that of nei. We therefore subcloned the 5-kb PstI fragment from pKY1 to pTZ18R. The DNA sequence of the fragments completely agreed with that of U38616. The detailed restriction map is shown in Fig. 1. Thus, plasmid pTZ18Rnei carries the nei ϩ gene. This finding further shows that the location of the nei gene is about 5 kb clockwise from the phr gene.Construction of nei and nth mutants. In the 5-kb EcoRIKpnI fragment containing nth ϩ , there are two PstI sites, one within the nth gene and the other 37 bp upstream from the ATG start codon. The nth ϩ gene was inactivated by cloning a 1.5-kb chlorampheni...

A variety of optically active carboxylic esters are produced by the kinetic resolution of racemic alpha-substituted carboxylic acids using achiral alcohols, aromatic or aliphatic carboxylic anhydrides, and chiral acyl-transfer catalysts. The combination of 4-methoxybenzoic anhydride (PMBA) or pivalic anhydride with the modified benzotetramisole-type catalyst ((S)-beta-Np-BTM) is the most effective for promotion of the enantioselective coupling reaction between racemic carboxylic acids and a novel nucleophile, bis(alpha-naphthyl)methanol, to give the corresponding esters with high ee's. This protocol was successfully applied to the production of nonracemic nonsteroidal anti-inflammatory drugs from racemic compounds utilizing the transacylation process to generate the mixed anhydrides from the acid components with the suitable carboxylic anhydrides.

beta-Adrenergic modulation is one of the most important regulatory mechanisms of ion channel function. Only recently, however, have beta-adrenergic effects on cardiac Na+ channel activity been recognized, and some diversity of effects has been reported in different preparations. We report studies of protein kinase A-dependent phosphorylation effects on cardiac Na+ current using the macropatch on-cell mode voltage-clamp technique to maintain cytoplasmic composition intact. During the first 5 minutes after addition of 8-(4-chlorophenylthio)cAMP to the bath, the midpoints of both voltage-dependent availability and conductance shifted in the hyperpolarizing direction an average of -7.5 +/- 2.8 mV (n = 31). Moreover, these effects were not species specific; similar results were obtained in canine, rabbit, and guinea pig myocytes, and a similar shift occurred after exposure to 5 microM isoproterenol. Maximum conductance did not change, nor did single-channel conductance. The shifts of conductance and voltage-dependent availability that were induced by protein phosphorylation were distinct from and independent of the slow background shift in kinetics. We measured the background shift to be less than 0.3 mV/min and to be restricted to the channels within the patch. Pretreatment of cells with a blocker of protein kinase, N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinoline sulfonamide (H-89), prevented the effect of 8-(4-chlorophenylthio)cAMP while not affecting the background shift in kinetics. Although clearly not the result of addition of a negatively charged phosphate to the inside face of the channel, cAMP-dependent phosphorylation affects the voltage-dependent kinetics, as expected, by an electrostatic interaction with the voltage sensor.