Human cytomegalovirus glycoprotein N (gpUL73-gN) genomic variants: identification of a novel subgroup, geographical distribution and evidence of positive selective pressure

Human cytomegalvirus (HCMV) ORF UL73 is a polymorphic locus, encoding the viral glycoprotein gpUL73-gN, a component of the gC-II envelope complex. The previously identified gN genomic variants, denoted gN-1, gN-2, gN-3 and gN-4, were further investigated in this work by analysing a large panel of HCMV clinical isolates collected from all over the world (223 samples). Sequencing and phylogenetic analysis confirmed the existence of the four gN genotypes, but also allowed the identification of a novel subgroup belonging to the gN-3 genotype, which was designated gN-3b. The number of non-synonymous (d(N)) and synonymous (d(S)) nucleotide substitutions and their ratio (d(N)/d(S)) were estimated among the gN genotypes to evaluate the possibility of positive selection. Results showed that the four variants evolved by neutral (random) selection, but that the gN-3 and gN-4 genotypes are maintained by positive selective pressure. The 223 HCMV clinical isolates were subdivided according to their geographical origin, and four main regions of gN prevalence were identified: Europe, China, Australia and Northern America. The gN variants were found to be widespread and represented within the regions analysed without any significant difference, and no new genotype was detected. Finally, for clinical and epidemiological purposes, a rapid and low-cost method for genetic grouping of the HCMV clinical isolates was developed based on the RFLP revealed by SacI, ScaI and SalI digestion of the PCR-amplified UL73 sequence. This technique enabled us to distinguish all four gN genomic variants and also their subtypes.

Ethnicity and skeletal Class III morphology: a pubertal growth analysis using thin-plate spline analysis

A longitudinal retrospective study using thin-plate spline analysis was used to investigate skeletal Class III etiology in Japanese female adolescents. Headfilms of 40 subjects were chosen from the archives of the Orthodontic department at Niigata University Dental Hospital, and were traced at IIIB and IVA Hellman dental ages. Twenty-eight homologous landmarks, representing hard and soft tissue, were digitized. These were used to reproduce a consensus for the profilogram, craniomaxillary complex, mandible, and soft tissue for each age and skeletal group. Generalized least-square analysis revealed a significant shape difference between age-matched groups (P < .001), except for the craniomaxillary complex at stage IVA. T test for size analysis showed unequivocally increased mandibular size in skeletal Class III, which directly increased the craniofacial size collectively (P < .05). A deviant profilogram showed anisotropy displaying as maxillary deficiency, acute cranial base, and obtuse gonial angle in addition to increased facial height at stage IIIB. Maxillary retrusion decreased while the mandible showed excessive incremental growth and a forward position caused by deficient orthocephalization at stage IVA. Craniomaxillary complex total spline and partial warps (PW)3 and 2 showed a maxillary retrusion at stage IIIB opposite an acute cranial base at stage IVA. Mandibular total spline and PW4, 5 showed changes affecting most landmarks and their spatial interrelationship, especially a stretch along the articulare-pogonion axis. In soft tissue analysis, PW8 showed large and local changes which paralleled the underlying hard tissue components. Allometry of the mandible and anisotropy of the cranial base, the maxilla, and the mandible asserted the complexity of craniofacial growth and the difficulty of predicting its outcome.

Changes in occlusal force and occlusal contact area after active orthodontic treatment: a pilot study using pressure-sensitive sheets

The aim of this study was to investigate functional changes in occlusion during retention. Data on occlusal force (OcFr) and occlusal contact area (OcAr) was obtained using the pressure-sensitive sheet, from a treated group (20 female patients) who had had four premolar extractions and treatment with standard edgewise appliances, and a control sample who matched the treated group of retainer for sex, age and Angle classification at 1 year after removal. A repeated measures analysis of variance showed that the mean values of total OcFr and OcAr in the treatment group gradually increased during retention and were 669.3 N and 15.1 mm2, respectively, at 1 year after removal of retainer. The increases of OcFr and OcAr were larger in the molar region, especially at the second molar. At 1 year after removal of retainer, OcFr and OcAr in the second molar were significantly larger in the treatment group than in the control sample, and a similar distribution pattern of OcFr and OcAr to those in normal occlusion was seen. These results suggested that balanced OcFr and OcAr might be obtained during and after retention, due to the settling of molars that had been discluded by active orthodontic treatment.

G(s) signaling is intact after disruption of lipid rafts

Membrane microdomains enriched in cholesterol and sphingolipids modulate a number of signal transduction pathways and provide a residence for heterotrimeric G proteins, their receptors, and their effectors. We investigated whether signaling through G(s) was dependent on these membrane domains, characterized by their resistance to detergents, by depleting cells of cholesterol and sphingolipids. For cholesterol depletion, rat salivary epithelial A5 cells were cultured under low-cholesterol conditions, and then treated with the cholesterol chelator methyl-beta-cyclodextrin. For sphingolipid depletion, LY-B cells, a mutant CHO cell line that is unable to synthesize sphingolipids, were incubated under low-sphingolipid conditions. Depletion of cholesterol or sphingolipid led to a loss or decrease, respectively, in the amount of Galpha(s) from the detergent-resistant membranes without any change in the cellular or membrane-bound amounts of Galpha(s). The cAMP accumulation in response to a receptor agonist was intact and the level slightly increased in cells depleted of cholesterol or sphingolipids compared to that in control cells. These results indicate that localization of Galpha(s) to detergent-resistant membranes was not required for G(s) signaling. Analysis of the role of lipid rafts on the kinetics of protein associations in the membrane suggests that compartmentalization in lipid rafts may be more effective in inhibiting protein interactions and, depending on the pathway, ultimately inhibit or promote signaling.

Tamoxifen agonism and estrogen antagonism of c-fos gene promoter activity through non-consensus-responsive elements in MC3T3-E1 osteoblasts

We find that the activity of a 0.4-kb human c-fos gene promoter (-404/+41), which lacks consensus estrogen-responsive elements (EREs), is regulated by estrogen receptor (ER) ligands in MC3T3-E1 osteoblastic cells through ERs in a manner distinct from ERE-mediated regulation. When ERalpha is coexpressed, both estrogens and antiestrogens upregulate promoter activity. When ERbeta is coexpressed, however, three tested antiestrogens affect c-fos promoter activity, with tamoxifen exerting the greatest effect, while estrogens have no such effect. The tamoxifen agonism through ERbeta is antagonized by 17beta-estradiol, while the 17beta-estradiol agonism through ERalpha is canceled by excess-level coexpression of ERbeta. Deletion analysis revealed that the sequence -206/-110 plays a crucial role in the ERbeta-mediated tamoxifen agonism. Interestingly, there is no ERbeta-mediated tamoxifen agonism when nonosteoblastic cells are tested. Taken together, these results suggest that the transcription of the c-fos gene is regulated by ER ligands possibly through non-ERE elements in ligand structure-, cell type-, and ER subtype-dependent manners.

Stereoselective pharmacokinetics and pharmacodynamics of disopyramide and its metabolite in rabbits

The extent to which interactions between enantiomers of disopyramide and between disopyramide and its metabolite, mono-N-dealkylated disopyramide (MND), contribute to stereoselectivity of the anti-arrhythmic effect has been investigated in rabbits by measuring the prolongation of the QUc interval. The plasma unbound fraction of disopyramide enantiomers was constant at a concentration range of 1.44-28.9 microM. An intravenous infusion study of the disopyramide enantiomer or racemate suggested that the S-enantiomer had a pharmacological effect, determined by linear regression analysis, approximately 3.3-times more potent than that of the R-enantiomer. Furthermore, the effect caused by racemic disopyramide was the sum of that elicited by both enantiomers individually. No significant difference was observed between the slope of linear regression analysis of intravenous infusion and that of intravenous bolus injection. Single intravenous bolus injection of MND did not affect the QUc intervals. In conclusion, the S-enantiomer of disopyramide was approximately 3.3-times more potent pharmacologically than the R-enantiomer. The relationship between plasma concentration of the disopyramide enantiomers and pharmacological effect was the sum of each enantiomer individually.

A novel inhibitor of ceramide trafficking from the endoplasmic reticulum to the site of sphingomyelin synthesis

Ceramide produced at the endoplasmic reticulum (ER) is transported to the lumen of the Golgi apparatus for conversion to sphingomyelin (SM). N-(3-Hydroxy-1-hydroxymethyl-3-phenylpropyl)dodecanamide (HPA-12) is a novel analog of ceramide. Metabolic labeling experiments showed that HPA-12 inhibits conversion of ceramide to SM, but not to glucosylceramide, in Chinese hamster ovary cells. Cultivation of cells with HPA-12 significantly reduced the content of SM. HPA-12 did not inhibit the activity of SM synthase. The inhibition of SM formation by HPA-12 was abrogated when the Golgi apparatus was made to merge with the ER by brefeldin A. Moreover, HPA-12 inhibited redistribution of a fluorescent analog of ceramide, N-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-pentanoyl)-d-erythro-sphingosine (C(5)-DMB-Cer), from intracellular membranes to the Golgi region. Among four stereoisomers of the drug, (1R,3S)-HPA-12, [corrected] which resembles natural ceramide stereochemically, was found to be the most active, although (1R,3S)-HPA-12 [corrected] did not affect ER-to-Golgi trafficking of protein. Interestingly, (1R,3S)-HPA-12 [corrected] inhibited conversion of ceramide to SM little in mutant cells defective in an ATP- and cytosol-dependent pathway of ceramide transport. These results indicated that (1R,3S)-HPA-12 [corrected] inhibits ceramide trafficking from the ER to the site of SM synthesis, possibly due to an antagonistic interaction with a ceramide-recognizing factor(s) involved in the ATP- and cytosol-dependent pathway.

Tongue and jaw muscle activities during chewing and swallowing in freely behaving rabbits

To study the function of the tongue and the coordination among jaw, tongue, and hyoid muscles during chewing and swallowing, we recorded the electromyographic activities from the masseter (Mas), digastric (Dig), mylohyoid (Myl), thyrohyoid (Thy), genioglossus (Gg) and styloglossus (Sg) muscles as well as jaw movement trajectories in the freely behaving rabbit. Three phases were identified in the chewing cycle (fast- and slow-closing and opening phases). The Gg (main tongue protruder) was active synchronously with the Dig during opening. The Sg (tongue retractor) showed two peaks in each cycle, one in the opening phase and the other in the closing phase. The latter may have a role in retracting the tongue during jaw closing. The co-contraction of the antagonists (i.e. Gg and Sg) during opening may contribute to shape the tongue to be appropriate to gather the foodstuff. In the swallowing cycle, five phases were identified, two in the closing phase and three in the opening phase. Regression analysis revealed that swallowing cycles had a longer cycle duration than that of the chewing cycles due to an extra phase (a pause) inserted in the opening phase, where there was a small co-activation in the jaw opening and closing muscles. The findings suggest that the swallowing center affects masticatory center in the central nervous system, and may also support the view that the masticatory burst timing begins with the Dig activities in the middle of the opening phase.

Sex-related differences in the renal disposition of the acidic metabolite of clentiazem in rat

1. Sex-related differences in the renal excretion of the acidic compounds (+)-(2S,3S)-8-chloro-2,3,4,5-tetrahydro-3-hydroxy-2-(4-hydroxyphenyl)-4-oxo-1,5-benzothiazepin-5-acetic acid (MA4; one of the acidic metabolites of clentiazem), probenecid (PB) and methotrexate (MTX) have been investigated in the 7-week-old male and female Sprague-Dawley rat using an in vivo renal clearance technique. 2. The extent of plasma protein binding of MA4, PB and MTX was approximately 96, 95 and 65%, respectively, and it did not differ significantly between the male and female rat. On the other hand, the unbound renal clearance (CLrf) of MA4 in the female was approximately 300 times higher than that in male, and the ratio of this clearance to the glomerular filtration rate (GFR) was approximately 10, suggesting that MA4 undergoes extensive active renal secretion in the female. Furthermore, the CLrf/GFR ratio was significantly decreased by co-administration of PB. In contrast, no sex-related difference in the renal excretion of PB could be detected because its CLrf was very low and reabsorption contributed extensively to its renal disposition. The CLrf/GFR for MTX was approximately 2.5 but did not differ significantly between the male and female. 3. The renal organic anion transport systems in rat show sex-related differences and have different substrate-specific characteristics.

[Epilepsy in patients with severe motor and intellectual disabilities: a long-term follow-up]

Long-term prognosis of epilepsy was investigated on 117 institutionalized patients with severe motor and intellectual disabilities, who were above 15 years of age in 1977, for a 20-year-period from 1977 to 1997. The incidence of epilepsy was 64.1% (75 patients), which was active in 28 patients (37.3%). The patients with the most severe psychomotor disabilities (bedridden and DQ < 20) showed the highest incidence of epilepsy (85.0%). Patients who died during the follow-up period showed higher incidence of active epilepsy (p < 0.01). During the follow-up of 94 surviving patients, persistence, relapse, and onset of seizures were frequent in patients with most severe intellectual disability, whereas those with less severe intellectual disability (20 < DQ < 35) were all seizure-free. Twenty-one patients had active epilepsy; symptomatic partial epilepsy in 17 (81.0%) and generalized epilepsy in 4 (19.0%). Notably, 5 of the 6 patients with persistent frequent seizures had age-dependent epileptic encephalopathy; persistent Lennox-Gastaut syndrome (LGS) (2 patients), severe epilepsy with multiple independent spike foci evolved from West syndrome (WS) and LGS (2 patients), and partial epilepsy with the history of LGS (1 patient).

Condylar bony change and self-reported parafunctional habits in prospective orthognathic surgery patients with temporomandibular disorders

OBJECTIVE

The purpose of this study was to investigate the relationship between self-reported parafunctional habits and condylar bony change and disk displacement in orthognathic surgery patients with signs and symptoms of temporomandibular joint disorders.

STUDY DESIGN

This is a cross-sectional retrospective study of pretreatment helical computed tomography scans and questionnaires of 94 female orthognathic surgery patients.

RESULTS

Condylar bony change, unilaterally or bilaterally, was found in 56.4% of the subjects, or 43.6% of the joints. Disk displacement, unilaterally or bilaterally, was seen in 59.6% of the subjects, or 45.7% of the joints. Bruxism and clenching was significantly associated with condylar bony change and disk displacement. Subjects with 3 or more parafunctional habits showed a significantly higher rate of bilateral condylar bony change.

CONCLUSION

Our results suggest that bruxism and clenching might be related to deterioration of the temporomandibular joint and that the greater the number of parafunctional habits a subject has, the higher the risk of condylar bony change.

Role of DnaB helicase in UV-induced illegitimate recombination in Escherichia coli

To study the involvement of DNA replication in UV-induced illegitimate recombination, we examined the effect of temperature-sensitive dnaB mutations on illegitimate recombination and found that the frequency of illegitimate recombination was reduced by an elongation-deficient mutation, dnaB14, but not by an initiation-deficient mutation, dnaB252. This result indicates that DNA replication is required for UV-induced illegitimate recombination. In addition, the dnaB14 mutation also affected spontaneous or UV-induced illegitimate recombination enhanced by the recQ mutation. Nucleotide sequence analyses of the recombination junctions showed that DnaB-mediated illegitimate recombination is short homology dependent. Previously, Michel et al. (B. Michel, S. Ehrlich, and M. Uzest, EMBO J. 16:430--438, 1997) showed that thermal treatment of the temperature-sensitive dnaB8 mutant induces double-stranded breaks, implying that induction of illegitimate recombination occurs. To explain the discrepancy between the observations, we propose a model for DnaB function, in which the dnaB mutations may exhibit two types of responses, early and late responses, for double-stranded break formation. In the early response, replication forks stall at damaged DNA, resulting in the formation of double-stranded breaks, and the dnaB14 mutation reduces the double-stranded breaks shortly after temperature shift-up. On the other hand, in the late response, the arrested replication forks mediated by the dnaB8 mutation may induce double-stranded breaks after prolonged incubation.

Convergent total synthesis of khafrefungin and its inhibitory activity of fungal sphingolipid syntheses

A convergent total synthesis of khafrefungin, a novel inhibitor of fungal sphingolipid syntheses isolated from the fermentation culture MF6020, has been developed. Alkenylboronic acid 5 and alkenyliodide 6, key fragments for the total synthesis, were prepared from the corresponding achiral aldehydes using tin(II)-catalyzed and Zr(IV)-catalyzed asymmetric aldol reactions, respectively. The Suzuki coupling reaction of these two fragments was successfully performed to give 17 in good yield. Through the total synthesis, epimerization of the C4 position having a rather highly acidic proton did not occur, indicating that khafrefungin was under strict conformational constraints to prevent the epimerization process. This characteristic stability of khafrefungin has also been discussed using semiempirical calculation and synthesis. Finally, khafrefungin derivatives have also been synthesized, and their antifungal activities have been measured to obtain information on the structure--activity relationships.

RT-PCR for detecting five distinct Tospovirus species using degenerate primers and dsRNA template

RT-PCR procedures for detection of multiple species of tospovirus from plant tissues were investigated. Downstream primers were designated from the 3' untranslated sequences of the S RNA. An upstream primer was designated from the degenerated sequences of the nucleocapsid protein. Approximately 450 bp DNA fragments were detected when Tomato spotted wilt virus (TSWV)- or Impatiens necrotic spot virus (INSV)- infected tissues were examined. Approximately 350 bp DNA fragments were detected when Watermelon silver mottle virus (WSMoV)- or Melon yellow spot virus (MYSV)-infected tissues were examined. Template RNA was extracted using CF 11 cellulose powder, and nonspecific amplification became unnoticeable when double-stranded RNA was used. The amplified fragments of WSMoV were differentiated from those of MYSV by AluI or TaqI digestion. The amplified fragments of TSWV were differentiated from those of INSV by DraI or HindIII digestion. An alstroemeria plant that was infected with an unidentified tospovirus was also examined, and a 350 bp fragment that was 97% identical to Iris yellow spot virus was detected. This method, therefore, detected at least five distinct Tospovirus species.

Pathophysiological roles of endogenous endothelin-1 in dogs with chronic heart failure produced by rapid right ventricular pacing

This study was designed to analyze the pathophysiological role of the endogenous endothelin (ET) system and the therapeutic approach to congestive heart failure (CHF) with ET(A)/ET(B) receptor antagonists in a canine CHF model. After 3 weeks of rapid right ventricular pacing (240 beats/min), concentrations of immunoreactive ET-1 in dogs increased approximately 2-fold in plasma and in the left and right ventricles but not in the lung. There were no meaningful changes in the density and affinity of total ET receptors, or in the ratio of ET(A) to ET(B) receptors. To clarify the functional role of endogenous ET, we examined the effects of acute injection of J-104132 (1 and 3 mg/kg i.v.), an ET(A)/ET(B) receptor antagonist, on cardiovascular and renal function in dogs with CHF. Compared with vehicle, J-104132 at both doses significantly decreased pulmonary artery pressure (PAP), pulmonary capillary wedge pressure (PCWP), and mean arterial pressure (MAP), and increased cardiac output (CO) and renal blood flow. J-104132 had no effects on heart rate and cardiac contractility. In addition, we examined whether J-104132 has an additive effect in the presence of enalaprilat. J-104132 (1 mg/kg i.v.) administered after enalaprilat (0.05 mg/kg i.v.) induced further decreases in MAP, PCWP and PAP, and further increases in CO, resulting in further decreases in total peripheral resistance. These results indicate that the endogenous ET system is exaggerated in CHF and has a detrimental effect on cardiac function. Therefore, J-104132 given alone or as combination therapy may play a beneficial role in the treatment of CHF in humans.

Intestinal first-pass metabolism of eperisone in the rat

PURPOSE

The purpose of this study was to clarify quantitatively the contribution of the intestine to the first-pass metabolism of eperisone in rats.

METHODS

The systemic availabilities of eperisone were estimated by administering the drug into the duodenum, portal vein, and femoral vein in rats in vivo. The first-pass metabolism of eperisone was confirmed in the perfused rat small intestine in situ. Metabolism of eperisone to an omega-1-hydroxylated metabolite (HMO), the first step of eperisone metabolism, was studied using rat intestinal microsomes in vitro.

RESULTS

The bioavailabilities in the intestine were 0.176 and 0.0879 at administration rates of 100 and 25 mg/h/kg, respectively, whereas those in the liver were 0.532 and 0.486, respectively. In the intestinal perfusion experiment, the appearance clearance to the portal vein from the intestinal lumen was much lower than the elimination clearance from the intestinal lumen, resulting in high metabolic clearance of eperisone in the small intestine. Eperisone was biotransformed to HMO by rat intestinal microsomes, and this was inhibited by alpha-naphthoflavone and an anti-rat CYP1A antibody.

CONCLUSIONS

Those data strongly suggest that eperisone may be metabolized to HMO by CYP1A in rat intestinal microsomes during the first-pass through the epithelium of the small intestine.

Temporal and spatial distribution of Fos protein in the parabrachial nucleus neurons during experimental tooth movement of the rat molar

The present study was undertaken to reveal spatio-temporal changes in the distribution of Fos-like immunoreactive (-IR) neurons in the parabrachial nucleus (PBN), one of the important relay nuclei for processing autonomic and somatosensory information from the oro-facial regions, following the induction of experimental tooth movement in rat upper molars. The experimental tooth movement was induced by the insertion of elastic rubber between the first and second upper molars. In normal animals, the PBN contained a smaller number of Fos-IR neurons. Following experimental tooth movement, the Fos-IR neurons increased in number significantly on both the ipsilateral and contralateral PBN, reaching a maximum at 4 h (about 10 times that of normal animals), and then decreased gradually. However, a significant number of Fos-IR neurons remained at 24 h post-operation. Remarkable side-by-side differences in the number of Fos-IR neurons were recognized at 1 to 4 h following the experimental tooth movement. Their number returned to normal (basal) levels at 5 days post. All subnuclei of PBN showed similar temporal changes in the number of Fos-IR neurons, this being particularly apparent in lateral PBN. Administrations of morphine (3 and 10 mg/kg, i.p.) drastically reduced the induction of Fos-IR neurons in all subnuclei of both the ipsilateral and contralateral PBN in a dose-dependent manner, and its effect was antagonized by pretreatment with naloxone (2 mg/kg, i.p.). The reduction of Fos-IR neurons by morphine pretreatment suggests that the appearance of Fos-IR neurons in the PBN may be partly due to the noxious stimulation and/or stress arising from tooth movement. The bilateral expression of Fos-IR neurons in the PBN indicates that the experimental tooth movement causes the activation of PBN neurons for the processing of somatosensory as well as autonomic information. The prolonged expression of Fos-IR neurons in all the subnuclei of bilateral PBN reflects clinical features of the transient discomfort and/or abnormal sensations, which many patients often complain about during orthodontic treatment.

A new double cuff sphygmotonometer for accurate blood pressure measurement

Accurate measurement of blood pressure (BP) is essential in the diagnosis and treatment of hypertension, but neither auscultatory nor oscillometric methods measure intra-arterial BP accurately in all circumstances. Algorithms for automatic BP-measuring devices differ from manufacturer to manufacturer, and no clear authorized algorithm criteria have yet been established. We have devised a double-cuff sphygmotonometer to measure BP on the basis of clear algorithms, and investigated the accuracy of this new method by comparing it with the photo-oscillometric method, which is the most accurate method for non-invasive measurement of intra-arterial BP. In the new method, a small cuff (3x6 cm) replaces the photo-sensor in the brachial cuff (13x24 cm) of the photo-oscillometric device, and BP is determined by means of the oscillation within the small cuff. The comparison based on procedures of AAMI-protocol was performed in 136 hypertensive patients and 54 normotensive subjects. The difference in systolic BP between the photooscillometric and double-cuff methods was -2.26+/-2.31 mmHg (89% under 5 mmHg), and the corresponding difference in diastolic BP was 1.9+/-2.50 mmHg (94% under 5 mmHg). In conclusion, we have devised a new double-cuff method which improves on the photo-oscillometric method, and although it seems to be less accurate than the photo-oscillometric method, the clarity of its algorithm makes it superior to the conventional oscillometric and auscultatory methods employing only one cuff.

Characterization of phagocytic hemocytes in Ornithodoros moubata (Acari: Ixodidae)

Effects of fetal bovine serum (FBS) and complement on phagocytic activity in Ornithodaros moubata (Murray 1877) hemocytes and protease activity in the hemocytes were examined. At least three morphologically different cell types, granulocytes, plasmatocytes, and prohemocytes, were detected in hemolymph of O. moubata, and granulocytes and plasmatocytes showed phagocytic activity. FBS altered phagocytic activity of granulocytes, and complement affected phagocytic activity of plasmatocytes. Ticks were inoculated with fluorescent polystyrene beads in combination with FBS or complement. The average number of beads in granulocytes was significantly higher in the FBS injected group than the control (P < 0.01). The percentage of bead-ingesting plasmatocytes in complement inoculated ticks was significantly lower than that in heat-inactivated complement inoculated and control ticks (P < 0.05). Proteases of tick hemocytes localized in small granules in the cytoplasm not only in phagocytic hemocytes but also in prohemocytes. Results suggested modulation of tick hemocyte function through serum components, and digestion of phagocytosed foreign bodies in the hemocytes.

Stereoselective pharmacokinetics and pharmacodynamics of verapamil and norverapamil in rabbits

We have estimated the pharmacokinetic and pharmacodynamic interactions of verapamil (VP) enantiomers and also the interaction between VP and its metabolite, norverapamil (NVP). ECGs of conscious rabbits were studied to determine the pharmacokinetics of VP enantiomers and racemic NVP in relation to their prolongation effect on PR intervals, which were used as an index of VP's antiarrhythmic effect. Plasma free fractions of VP enantiomers showed constant values at concentrations ranging from 0.022 to 1.10 microm. There were no interactions between enantiomers or between VP and NVP. The pharmacological effect of the S-enantiomer (S-VP), which was determined by linear regression analysis, showed it was about 20 times more potent than that of the R-enantiomer (R-VP). The effect of racemic VP was the simple sum of those elicited by both enantiomers. These relationships were not significantly different between intravenous infusion and bolus injection. Simultaneous intravenous infusion of NVP had no influence on the PR intervals. In conclusion, we demonstrated that the relationship between plasma unbound concentration of VP enantiomers and their pharmacological effect was the simple sum of two enantiomers.

Suppression of gamma ray-induced illegitimate recombination in Escherichia coli by the DNA-binding protein H-NS

To study the mechanism of gamma-ray-induced illegitimate recombination, we examined the formation of lambdabio transducing phage in Escherichia coli after gamma-ray irradiation. We show that gamma-ray irradiation enhances the formation of lambdabio transducing phage during prophage induction. Moreover, an hns mutation synergistically enhanced the incidence of lambda-ray-induced illegitimate recombination. Next we determined the sequences at the recombination junctions of the lambdabio transducing phages induced by gamma-ray irradiation. Most of the recombination sites coincided with known hotspots. Among them, hotspot I accounted for 67% and 77% of gamma-ray-induced lambdabio transducing phages in the wild type and the hns mutant, respectively. Therefore, the recombination sites appear to occur mostly at hotspot I or at other hotspots, but rarely at non-hotspot sites. These results suggest that types of DNA damage other than the double-strand breaks induced at random sites are mainly responsible for the introduction of the site-specific or region-specific DNA double strand breaks that lead to recombination at the hotspots. The results also showed that the recombination events took place between DNA sequences possessing short stretches of homology. H-NS protein, which binds to curved DNA, suppresses illegitimate recombination in the presence and absence of gamma-ray irradiation. Models for gamma-ray-induced illegitimate recombination are discussed.