Population pharmacokinetics, protein binding and antiarrhythmic effects of disopyramide enantiomers in arrhythmic patients

Disopyramide (DP) is widely used as an antiarrhythmic agent. The antiarrhythmic effects of its enantiomers differ from each other and its metabolism and protein binding are also stereoselective. Population pharmacokinetic parameters of DP racemate, enantiomers (S(+)-DP, R(-)-DP), and their unbound concentrations (uDP, S(+)-uDP and R(-)-uDP) were analyzed using the nonlinear mixed effect model (NONMEM) program. Data were available from 108 points of 33 arrhythmic patients on maintenance therapy with DP racemate. We evaluated the factors to which pharmacokinetic parameters are attributed and the relationships between each serum concentration and the antiarrhythmic effect. A one-compartment model was fitted to the data using NONMEM. For DP, S(+)-DP and R(-)-DP, elimination rate constants (kes) were estimated as 0.0648, 0.0663 and 0.0691/h, respectively and the mean apparent volume of distribution (Vd/F) were estimated as 63.2, 54.1 and 71.6 l, respectively. Using the ke and Vd/F values estimated by NONMEM, time-concentration curves were well fitted to the observed data. Unbound fractions of both DP enantiomers showed nonlinearity and the binding ratio of S(+)-DP was 0.84 +/- 0.07, which was higher than that of R(-)-DP [0.70 +/- 0.11 (p < 0.01)]. Unbound fractions of both DP enantiomers correlated with alpha1-acid glycoprotein (AGP) (p < 0.01). On the other hand, using NONMEM, a significant proportion of the variability of Vd/F could be attributed only to AGP (p < 0.001). NONMEM was able to clarify the pharmacokinetic features in the protein binding of DP. Individual steady state concentrations were estimated by NONMEM using the Bayesian method. The average unbound concentrations of all nine responders were higher than those of the four non-responders, even though this difference was not significant. Unbound concentrations may reflect drug concentrations in the tissue, which suggests that these concentrations may indicate an antiarrhythmic effect rather than the total concentration.

Application of synchrotron X-ray imaging to phase objects in orthopedics

Novel imaging of the fine structures of the ribs of a pig and a specimen of human osteosarcoma utilizing the spatial coherence of X-rays was successfully performed with an incident X-ray energy of 30 keV at SPring-8, Japan. The image contrast appearing at the periphery of trabecular bone, small calcifications and small fractures is caused by the phase shift of the X-rays at the boundary of these objects that have different X-ray refractive indices. The image is recorded on mammography film without an intensifying screen. Comparison of the image contrast using different sample-to-film distances, Z, such as Z = 5 m and Z approximately 0 m, showed that the former images were always more informative, i.e. better in resolution and/or image contrast when imaging trabecular bone, bone marrow and small fractures in compact bone, and for imaging cartilage. Radiography using synchrotron X-rays for phase objects should be a powerful tool for diagnosis in orthopedics, especially for bone disease.

Avian retrovirus infection causes naturally occurring glioma: isolation and transmission of a virus from so-called fowl glioma

So-called fowl glioma is characterized by multiple nodular gliomatous growths associated with disseminated non-suppurative encephalitis. To investigate the possibility of the induction of the gliomatous lesions, chicks of Japanese bantams (Gallus gallus domesticus) and specific pathogen free chickens (C/O strain White Leghorn) were intracerebrally inoculated with a brain homogenate or culture supernatant from a bantam affected with fowl glioma. All bantams and 16 chickens (89%) in the inoculated groups showed non-suppurative encephalitis, and the 18 bantams (82%) and five chickens (28%) developed multiple nodules consisting of aggregations of astrocytes in the cerebrum. These astrocytes had avian leukosis virus (ALV) antigen. By Southern blot analysis, the ALV sequence was detected both in DNA prepared from the brains of the inoculated birds and in DNA from the inoculum. Ultrastructurally, tadpole-shaped particles, approximately 100 nm in diameter, were detected in the concentrated supernatant of the chicken embryo fibroblasts, and budding of the particles was noted. These results substantiated that fowl glioma of the bantams could be transmitted by intracerebral inoculation of the affected tissue and that the causal agent was an unidentified strain of ALV.

Comparison of lansoprazole and famotidine for gastric acid inhibition during the daytime and night-time in different CYP2C19 genotype groups

BACKGROUND

The acid inhibitory effect of lansoprazole depends on the S-mephenytoin 4'-hydroxylase (CYP2C19) genotype status. The effect of famotidine is independent of this genotype.

AIM

To investigate the acid inhibitory effects of lansoprazole vs. famotidine during the daytime and night-time with reference to different CYP2C19 genotypes.

METHODS

Fifteen healthy volunteers were given 20 mg famotidine twice a day or 30 mg lansoprazole once a day for 8 days. On post-dose day 8, 24-h intragastric pH monitoring was performed.

RESULTS

During the daytime, the intragastric pH with lansoprazole was significantly higher than that with famotidine in the heterozygous extensive metabolizer group, whereas no significant difference was observed in the homozygous extensive metabolizer group. During the night-time, the intragastric pH with famotidine was quite similar to that with lansoprazole in the heterozygous extensive metabolizer and poor metabolizer groups. However, during the night-time, the intragastric pH with famotidine was significantly higher than that with lansoprazole in the homozygous extensive metabolizer group.

CONCLUSIONS

An insufficient acid inhibition by lansoprazole during the night-time in the homozygous extensive metabolizer group could be compensated for by famotidine. CYP2C19 genotype testing appears to be useful for predicting the optimal acid inhibitory drug treatment collated with circadian intragastric pH change.

Immunohistological analysis of thymoma by molecules differentially expressed in the thymic cortex and medulla, and its application in the differential diagnosis of thymoma from esophageal and lung cancer

The purpose of this study was to verify the WHO classification of thymic tumors using immunohistological methods, and to discover whether these methods can be applied to differentiate thymoma from squamous cell carcinoma (SCC) of the esophagus and the lung. Twenty-nine thymoma cases were classified according to WHO and were then immunohistologically examined for the positivity of these molecules. All thymoma cases investigated in this study were positive for IL-1R, and most of them were also positive for bek. In contrast, UH-1 was highly positive in B1 and B2 type thymomas, but negative or weakly positive in A, AB and B3 type thymomas. Twelve esophageal cancers and 21 lung cancers were also examined for the positivity of the same molecules. All esophageal cancers were negative for UH-1. Three of 12 cases were weakly positive for IL-1R, and four of these 12 cases were also weakly positive for bek. Twelve of 21 lung cancer cases were adenocarcinomas, all of them negative for IL-1R, bek and UH-1. Nine of 21 lung cancer cases were SCCs, all of them negative for UH-1. Eight of nine SCC cases were strongly positive for IL-1R, while seven of these were weakly positive for bek. We conclude that the WHO classification of thymic tumors is still valid as demonstrated by immunohistological analysis and that the positivity of UH-1, IL- 1R and bek might be helpful in differentiating thymoma from SCC of the esophagus and the lung.

Effects of CYP2C19 genotypic differences in the metabolism of omeprazole and rabeprazole on intragastric pH

BACKGROUND

Omeprazole is mainly metabolized in the liver by CYP2C19, a genetically determined enzyme, whereas rabeprazole is mainly reduced non-enzymatically and partially metabolized by CYP2C19. The therapeutic effects of rabeprazole are therefore assumed to be less affected by an individual's CYP2C19 status.

AIM

To investigate the acid inhibitory effects and plasma levels of omeprazole and rabeprazole with reference to different CYP2C19 genotypes.

METHODS

Fifteen healthy volunteers took a daily dose of 20 mg of omeprazole or rabeprazole for 8 days. On post-dose days 1 and 8, 24-h profiles of intragastric pH were recorded and plasma concentrations of omeprazole, rabeprazole and their metabolites were determined.

RESULTS

After single and repeated doses of omeprazole, the intragastric pH values and plasma concentrations of omeprazole and its metabolites were significantly dependent on the CYP2C19 genotype. Significant differences in the same kinetic and dynamic parameters were also observed after single doses of rabeprazole. Although the plasma levels of rabeprazole differed among the different CYP2C19 genotype groups after repeated doses, no significant differences in intragastric pH values were observed.

CONCLUSIONS

The acid inhibitory effects of omeprazole and rabeprazole are significantly dependent on the CYP2C19 genotype status, as well as on their intrinsic pharmacokinetic and pharmacodynamic characteristics and dosing schemes.

[A case of spinocerebellar ataxia type 6 with hypochondriasis and severe parkinsonism]

We report a case of 68-year-old woman who was diagnosed spinocerebellar ataxia type 6 (SCA 6) by genomic testing. She presented hypochondriasis, parkinsonism, and ataxia. Since the age of 60, she noted difficulty in walking due to dizziness, and MRI showed minimal cerebellar atrophy. She became unable to walk without assistance at the age 67. She was referred to us when she was 68 years old. She had no family history of cerebellar ataxia, and her general physical examination was normal. Her speech was fluent, with neither slurring nor scanning, and she complained of much anxiety regarding her physical condition and was diagnosed as having hypochondriasis. Neurological examination revealed parkinsonism consisting of small steppage gait, mask-like face, akinesia, rigidity of neck and limbs, and postural instability. She also showed cerebellar signs such as saccadic smooth pursuit, ataxia of upper and lower limbs, and increased tendon reflexes. Her parkinsonism had developed slowly and symmetrically yet she showed a lack of response to levodopa. Our results suggest that the genomic testing is useful for differential diagnosis for the diseases presenting ataxia and parkinsonism, even if the family history is negative.

Immunohistochemical diagnosis of Cryptococcus neoformans var. gattii infection in chronic meningoencephalitis: the first case in Japan

Cryptococcus neoformans (C. neoformans) var. gattii infection usually occurs in tropical and subtropical areas, and rarely in the northern hemisphere. We report the first Japanese with cryptococcal meningoencephalitis caused by C. neoformans var. gattii infection that occurred during a trip to Australia. This agent was identified in a cerebellar biopsy specimen by immunohistochemical technique with serotype-specific anti-sera. Because the meningitis caused by it did not respond well to conventional therapy, we used an aggressive therapeutic regimen to successfully treat the patient. Even in areas where C. neoformans var. gattii does not exist, this infection should be considered possible as a travel-related infection.

Insulin inhibits coronary endothelial cell calcium entry and coronary artery relaxation

Hyperinsulinemia is closely related to coronary artery disease. Endothelial cells are important for the control of vascular tone, and dysfunction of endothelial cells has been implicated in coronary artery disease. The direct effects of insulin on coronary endothelial cells are nonetheless unknown. In this study, the acute effects of high-dose insulin were investigated on agonist-induced intracellular Ca(2+) concentration ([Ca(2+)](i)) in porcine coronary endothelial cells and coronary relaxation. Bradykinin (10 n M ) and cyclopiazonic acid (100 microM), an inhibitor of the endoplasmic reticulum Ca(2+)-ATPase, provoked large increases in [Ca(2+)](i) in coronary endothelial cells. This increase was dose-dependently inhibited by a 10-min preincubation with high doses of insulin (10, 30, 100 mU/ml). Under Ca(2+)-free conditions, bradykinin and cyclopiazonic acid provoked transient, small increases in [Ca(2+)](i). These increases were not affected by pretreatment with insulin (100 mU/ml). Bradykinin (1, 10, 100, 1,000 n M ) and cyclopiazonic acid (10 microM) significantly relaxed porcine coronary artery rings precontracted with histamine (1 microM). The vasodilator effects of bradykinin and cyclopiazonic acid were dose-dependently inhibited by insulin. These acute effects were not observed at physiologic concentrations. Our data indicate that high-dose insulin inhibits agonist-induced Ca(2+) response in coronary endothelial cells and attenuates agonist-induced coronary vasodilatation. The study suggests that hyperinsulinemia might be associated with coronary artery disease via derangement of endothelial Ca(2+)-dependent functions.

Gas6 induces mesangial cell proliferation via latent transcription factor STAT3

Mesangial cell proliferation is essential for the pathogenesis and progression of glomerular disease. Previously, we showed that Gas6 plays a pivotal role in mesangial cell proliferation in vitro and in vivo. In the present study, we identified downstream targets of Gas6 signaling to examine the role in mesangial cell proliferation in vitro and in vivo. We found that Gas6 tyrosine phosphorylates STAT3 (signal transducers and activators of transcription) with concomitant translocation to the nucleus and induces STAT3-dependent transcriptional activation in cultured mesangial cells. Expressing dominant negative STAT3 inhibited Gas6-mediated transcriptional activation of STAT3 and abolished Gas6-induced mesangial cell proliferation. In a model of mesangial proliferative glomerulonephritis, STAT3 is phosphorylated in mesangial cells, and its phosphorylation peaks at day 8 after the injection of anti-Thy1.1 antibody. Inhibition of Gas6 by warfarin and the extracellular domain of its receptor, Axl, abolished phosphorylation of STAT3 in vivo. Thus, our in vitro and in vivo findings indicate that autocrine growth factor Gas6 induces mesangial cell proliferation via latent transcription factor STAT3. Therefore, STAT3 might be a new therapeutic target for kidney disease induced by mesangial proliferation.

Effect of high-dose lansoprazole on intragastic pH in subjects who are homozygous extensive metabolizers of cytochrome P4502C19

BACKGROUNDS AND AIM

Lansoprazole is mainly metabolized by cytochrome P4502C19 (CYP2C19) in the liver. The effect of lansoprazole is assumed to be insufficient in subjects who are homozygous extensive metabolizers of CYP2C19. This study aimed to examine whether the CYP2C19 genotype status affected the acid-inhibitory effects of lansoprazole and to develop a strategy to overcome this pharmacogenetic problem.

METHODS

Eighteen Helicobacter pylori-negative healthy volunteers, whose CYP2C19 genotypic status had been assessed, participated in the study. They consisted of 7 subjects who were homozygous extensive metabolizers, 7 subjects who were heterozygous extensive metabolizers, and 4 subjects who were poor metabolizers of CYP2C19, who took a placebo or lansoprazole 30 mg once daily in the morning for 8 days. On day 8 of dosing, 24-hour intragastric pH values were recorded. Five of the homozygous extensive metabolizer subjects underwent the 24-hour intragastric pH monitoring on day 8 of dosing of lansoprazole 30 mg 4 times daily.

RESULTS

When lansoprazole 30 mg was given once daily, the mean 24-hour intragastric pH values in the subjects who were homozygous extensive metabolizers, heterozygous extensive metabolizers, and poor metabolizers were 4.5, 4.9, and 5.5, respectively (P <.005). On day 8 of dosing of lansoprazole 30 mg 4 times daily in subjects who were homozygous extensive metabolizers, the mean 24-hour intragastric pH value was 7.4.

CONCLUSION

The effect of lansoprazole on intragastric pH depended significantly on CYP2C19 genotype status. Complete acid inhibition could be achieved by the frequent administration of lansoprazole (eg, 30 mg 4 times daily) in subjects who were homozygous extensive metabolizers. A genotyping test of CYP2C19 status appears useful for prescribing an optimal dosing scheme of lansoprazole.

Hepatocyte transplantation: clinical and experimental application

Hepatocyte transplantation has been proposed as an alternative to whole-organ transplantation to support many forms of hepatic insufficiency. Based on a significant body of work, the technique of hepatocyte transplantation has recently moved into the clinic in order to reestablish liver function without organ transplantation or to bridge the time between whole-organ liver transplantation. In addition, hepatocyte transplantation has also been proposed as a liver-directed gene therapy for a number of inherited hepatic disorders by transplanting either freshly isolated hepatocytes or genetically altered hepatocytes. To establish a research system based on the developing technology of hepatocyte transplantation, chimeric small animal models using human hepatocytes have recently been established, which would allow the study of human hepatocyte-specific functions, such as hepatitis viral infection and replication in vivo. Various aspects related to the recent progress and existing obstacles in the area of hepatocyte transplantation are summarized in this report.

[Memoirs on Chlorodyne and Shinyaku]

Dr. J. Collins Browne, a British army surgeon in India, invented a secret remedy for cholera-infected patients in the fifth decade of the 19th century. After his resignation from the army, the formula was given to a pharmacist in London for the purpose of manufacture and marketing as a patented medicine named Chlorodyne. Chlorodyne was well-accepted as paregoric for several decades. The formula of Chlorodyne was adopted in the 3rd Revision of the British Pharmacopoeia (1885) as "Compound Tincture of Chloroform and Morphine." In 1906, the 3rd Revision of Japanese Pharmacopoeia listed "Compound Tincture and Morphine" according to the formula of the 4th Revision of British Pharmacopoeia (1898). References written in 1870 and 1873 recorded the importation of Chlorodyne to Japan. In 1871, Dr. Jyun Matsumoto, Chief Military Surgeon Major General advised the manufacturers of traditional medicines to produce patented medicines to spread in western countries. Preparations of formula seeming to resemble Chlorodyne was named "Shinyaku" and were marketed from 1872. The name Shinyaku represented a medicine of marvellous efficacy, because the word split, Shin and Yaku, means "divine or almighty" and "medicine," respectively. Although the orginal formula of Shinyaku was not preserved, modifications of the formula were made to meet legal restrictions over the change of time. Needless to say, Morphine hydrochloride, Diluted hydrocyanic acid and tincture of Indian hemp were replaced with other ingredients to assure safety and lately Chloroform deleted from the formula as well. Shinyaku enjoyed good sales for a long time owing to its efficacy of restorative and refrigerant.

[Memorandum on the origin of Rx, the signal be employed to the heading in the prescription]

The symbol variously written Rp. Rx. or R. is still employed by physicians to head their prescriptions. In our country, we have learned and believe that the origin of the symbol is an abbreviation of the Latin word for "recipe." In Europe, another suggestion of the origin of the symbol appears to represent the astronomical sign of the planet Jupiter. There is, however, no evidence to support this suggestion. As regards the Jupiter symbol it is probably that printer may have used the sign as the nearest approach he had in type to the abbreviated sign for recipe. It is believed that the confusion between the two symbols is due to a mere typographical coincidence. A careful examination of the various styles of writing the symbol, clearly shows that the sign was originally adopted as an abbreviation of the word "recipe." Recently, it has been suggested that the symbol originates in "the eye of Horus," but, as regards the eye of Horus symbol, much more still remains to be examined. Thus, I will suspend judgement until the facts of the matter become clear, and expect further researches in future.

Effects of subchronic lithium chloride treatment on G-protein subunits (Golf, Ggamma7) and adenylyl cyclase expressed specifically in the rat striatum

Lithium salt has been widely used as a treatment for mania, but the mechanism of its effect remains unknown. Previously, by studying c-fos expression, we showed that the striatum was a possible target region for the antimanic effects of lithium salt. The present study focused on the effect of subchronic lithium chloride treatment on G-proteins (Golf, Ggamma7) and adenylyl cyclase type V, which are expressed specifically in the rat striatum. Subchronic lithium chloride treatment significantly increased the level of Golf protein, a stimulant alpha-subunit of G-protein, by 53.5% (P<0.01), but the levels of Ggamma7 and adenylyl cyclase type V did not change. This increased level of Golf protein was found after 2 weeks of lithium chloride treatment, but not after 1 week, and the level returned to the basal level 1 week after withdrawal of lithium chloride. This result suggests that the level of Golf protein increases to compensate for the suppression of the adenylyl cyclase system by lithium, and that this increase may account for the "rebound" phenomenon, which is the relapse observed after abrupt discontinuation of lithium salt treatment.

Severe hypercholesterolemia, hypertriglyceridemia, and atherosclerosis in mice lacking both leptin and the low density lipoprotein receptor

Leptin-deficient mice (ob/ob) are an excellent murine model for obesity, insulin resistance, and diabetes, all of which are components of a multiple risk factor syndrome that, along with hypercholesterolemia, precipitates a potential high risk for atherosclerosis. In the current study, we show an unexpectedly severe hyperlipidemia in ob/ob mice on a background of low density lipoprotein receptor (LDLR) deficiency (-/-). Doubly mutant mice (LDLR-/-;ob/ob) exhibited striking elevations in both total plasma cholesterol (TC) and triglyceride (TG) levels (1715 +/- 87 and 1016 +/- 172 mg/dl, respectively), at age 3-4 months, resulting in extensive atherosclerotic lesions throughout the aorta by 6 months. Lipoprotein analyses revealed the elevated TC and TG levels to be due to a large increase in an apoB-containing broad-beta remnant lipoprotein fraction. While fasting, diet restriction, and low level leptin treatment significantly lowered TG levels, they caused only slight changes in TC levels. Hepatic cholesterol and triglyceride contents as well as mRNA levels of cholesterologenic and lipogenic enzymes suggest that leptin deficiency increased hepatic triglyceride production but did not change cholesterol production in ob/ob mice regardless of their LDLR genotype. These data provide evidence that the hypertriglyceridemia and hypercholesterolemia in the doubly mutant mice are caused by distinct mechanisms and point to the possibility that leptin might have some impact on plasma cholesterol metabolism, possibly through an LDLR-independent pathway. This model will be an excellent tool for future studies on the relationship between impaired fuel metabolism, increased plasma remnant lipoproteins, diabetes, and atherosclerosis.

Survey of Theileria parasite infection in cattle in Cambodia and Vietnam using piroplasm surface protein gene-specific polymerase chain reaction

A survey of Theileria parasite infection in cattle in Cambodia and Vietnam was carried out by using allele-specific polymerase chain reaction. A total of 137 blood samples from draught animals in Cambodia and 40 blood samples from dairy cattle in Vietnam were analyzed. In Cambodia, 69 out of 137(50.4%) samples were PCR-positive containing mainly the Thai and the C type parasites. In Vietnam, 11 (27.5%) samples were positive and all were of the Thai type parasite.

Identification of a novel gene, Mblk-1, that encodes a putative transcription factor expressed preferentially in the large-type Kenyon cells of the honeybee brain

Mushroom bodies (MBs) are considered to be involved in higher-order sensory processing in the insect brain. To identify the genes involved in the intrinsic function of the honeybee MBs, we searched for genes preferentially expressed therein, using the differential display method. Here we report a novel gene encoding a putative transcription factor (Mblk-1) expressed preferentially in one of two types of intrinsic MB neurones, the large-type Kenyon cells, which makes Mblk-1 a candidate gene involved in the advanced behaviours of honeybees. A putative DNA binding motif of Mblk-1 had significant sequence homology with those encoded by genes from various animal species, suggesting that the functions of these proteins in neural cells are conserved among the animal kingdom.

Hepatitis B virus reactivation in a patient with chronic GVHD after allogeneic peripheral blood stem cell transplantation

We report a patient with fatal hepatitis B virus (HBV) reactivation after treatment for chronic graft-versus-host disease (GVHD) following allogeneic peripheral blood stem cell transplantation to treat chronic myelogenous leukemia. The presence of antibodies to hepatitis B surface antigen (HBsAb) prior to transplantation indicated previous HBV infection. Liver damage first developed 8 months after transplantation with the disappearance of HBsAb. Hepatitis B antigen was first noted during an examination of liver damage that occurred 22 months after transplantation. Retrospective examination of serum by real-time detection polymerase chain reaction (RTD-PCR) revealed HBV in both the first and second episodes of liver damage (89 copies/mL and 2 x 10(6) copies/mL, respectively). HBV may have been reactivated, leading to fatal liver damage in this HBsAb-positive patient. We propose that RTD-PCR-based analysis should be performed to diagnose liver dysfunction after hematopoietic stem cell transplantation.

Cloning and characterization of a novel mouse immunoglobulin superfamily gene expressed in early spermatogenic cells

We cloned and characterized a novel immunoglobulin superfamily gene from the cDNA library of adult mouse testis. This gene was expressed in the spermatogenic cells and hence termed SgIGSF. The predicted SgIGSF protein was composed of 445 amino-acid residues and contained a signal peptide, three extracellular immunoglobulin (Ig)-like domains, a transmembranous domain, and a cytoplasmic domain. SgIGSF mRNA consisted of two size species, 2.1- and 4.5-kb in length. Besides testis, SgIGSF mRNA was also expressed in a variety of organs, including the cerebrum, liver, kidney, and epididymis. The testis and liver expressed both the 2.1- and 4.5-kb transcripts, whereas the cerebrum and epididymis predominantly expressed the 4.5-kb one. In situ hybridization analysis in testis revealed that SgIGSF mRNA signal was localized to the spermatogenic cells from spermatogonia to zygotene spermatocytes. These results suggested that SgIGSF occurs in the plasma membrane of spermatogenic cells during the earlier stages of spermatogenesis.

Effects of CYP3A4 inhibition by diltiazem on pharmacokinetics and dynamics of diazepam in relation to CYP2C19 genotype status

Diazepam is metabolized by CYP2C19 and CYP3A4 in the liver. CYP2C19 shows genetic polymorphism associated with the poor metabolizer (PM) and extensive metabolizer (EM) phenotypes. The aim of this study was to assess the effect of diltiazem, a CYP3A4 inhibitor, on pharmacokinetics and dynamics of diazepam in relation to CYP2C19 genotype status. Thirteen healthy volunteers (eight EMs and five PMs) were given placebo or diltiazem (200 mg) orally for 3 days before and for 7 days after the oral 2-mg dose of diazepam in a double-blind, randomized, crossover manner. The pharmacokinetics and pharmacodynamics of diazepam were assessed with and without diltiazem. Plasma concentrations and area under the plasma concentration-time curves (AUCs) of diazepam and N-desmethyldiazepam were significantly greater in the PM compared with the EM group during the placebo phase. Diltiazem significantly increased AUC and prolonged elimination t(1/2) of diazepam in both the PM and EM groups. These pharmacokinetic changes, however, caused no significant difference in the pharmacodynamics between the two trial phases. Diltiazem affects the pharmacokinetics of diazepam in the PM and EM groups of CYP2C19. Inhibition of CYP3A4 by a concomitant substrate drug like diltiazem may cause a pharmacokinetic interaction with diazepam irrespective of CYP2C19 genotype status, but whether this interaction would reflect a pharmacodynamic change of diazepam remains unconfirmed by our study.

Loss of syndecan-1 and increased expression of heparanase in invasive esophageal carcinomas

Heparan sulfate proteoglycans play important biological roles in cell-cell and cell-matrix adhesion, and are closely associated with growth factor actions. Loss of syndecan-1, a cell surface-bound heparan sulfate proteoglycan, has been reported for advanced head and neck carcinomas, and expression of endoglycosidic heparanase, which cleaves heparan sulfate glycosaminoglycans (HS-GAGs), is associated with invasion and metastatic potential of malignant tumors. Paraffin sections of 103 primary esophageal squamous cell carcinomas were immunohistochemically examined for the expression of syndecan-1 core protein, HS-GAGs and heparanase protein, and the results were compared with various clinicopathological parameters, such as invasion depth. For 16 cases, fresh tumor samples were quantitatively analyzed for heparanase and syndecan-1 mRNA expression by real-time RT-PCR in addition to the immunohistochemical studies. Syndecan-1 core protein and HS-GAGs expression was significantly decreased in pT2 and pT3 cases compared with their pTis and pT1 counterparts. Decreased expression of core protein and HS-GAGs was correlated with the incidence of lymphatic invasion, and venous involvement. Furthermore, decreased expression of HS-GAGs was correlated positively with the incidence of nodal metastasis and distant organ metastasis, and negatively with the grade of tumor cell differentiation. The percentage of cytoplasmic heparanase protein-positive cases increased significantly in pT2 and pT3 cases compared to that in pTis and pT1 cases, and this was associated with lymphatic invasion, and venous and lymph nodal involvement. The level of heparanase mRNA was inversely correlated with the degree of HS-GAGs expression rather than core protein. In conclusion, loss of syndecan-1 and heparanase overexpression in esophageal squamous cell carcinomas are closely associated with malignant potential. Regarding the mechanism of loss of HS-GAGs, heparanase upregulation appears to play an important role.

Seroepidemiological survey of distemper virus infection in the Caspian Sea and in Lake Baikal

Forty Caspian seals were surveyed seroepidemiologically between 1993 and 1998 around the times of mass mortality that occurred in 1997 in the Caspian Sea and seven Baikal seals were also surveyed in 1998. Virus neutralizing tests and ELISA clearly suggested that distemper virus epidemic was caused in Caspian seals before the spring of 1997 and that CDV infection continued to occur in Lake Baikal in recent years.

Tumor necrosis factor alpha and its receptors in experimentally bovine leukemia virus-infected sheep

To examine whether tumor necrosis factor alpha (TNF alpha) contributes to the pathogenesis of bovine leukemia virus (BLV) infection, the mRNA expression patterns of TNF alpha and its receptors, type 1 (TNF R1) and type 2 (TNF R2) were investigated. Sheep inoculated with BLV were divided into two groups; one was BLV-positive and the other BLV-negative based on the detection in peripheral blood mononuclear cells (PBMC). Expression of TNF R1 mRNA was down-regulated in PBMC from the BLV-positive compared to BLV-negative sheep. No difference was shown in the expression levels of TNF R2 mRNA between the two groups. Furthermore, proliferative responses of PBMC in the presence of TNF alpha were observed from the BLV-positive, but not BLV-negative sheep. Membrane-bound TNF alpha (mTNF alpha) is thought to be one of the ligands, inducing B-cell activation. Flow cytometric analysis demonstrated that the number of PBMC, that were positive for mTNF alpha expression, was increased in the BLV-positive sheep. Thus, the expression of TNF alpha and its receptors may be closely associated with lymphocytosis induced by BLV.

Phylogenetic relationships of bovine immunodeficiency virus in cattle and buffaloes based on surface envelope gene sequences. Brief report

Isolates of bovine immunodeficiency virus (BIV) exhibit a striking genomic diversity, most of which are located in the viral envelope gene. Since this property of the BIV group of viruses may play an important role in the pathobiology of the virus, the surface envelope gene, particularly the conserved (C) 2, hypervariable (V) 1, V2 and C3 regions, of eleven different isolates from different environments with different bovine breeds naturally infected with BIV, including dairy cows in Japan, buffaloes in Pakistan and draught animals in Cambodia, were sequenced. When compared to the nucleotide sequence of American BIV isolates, all Asian BIV field isolates seem to be smaller, several base substitutions were observed in the V1 region, and deletions were also found in the V2 region of env gene in these samples. However, deduced amino acid sequences were not so different among isolates from different bovine breeds, suggesting that bovine susceptibility to BIV infection may not depend upon bovine breed or buffaloes. Moreover, phylogenetic analysis revealed that genotypes were distinct between Asian and American BIV isolates and these results also provide an information on the molecular epidemiology of naturally occurring BIV infection in cattle and buffaloes.

Expression of two subtypes of human IFN-alpha in transgenic potato plants

Plant expression systems have advantages over other in vitro expression systems in terms of low production costs and low risk of contamination by animal viruses or bacterial endotoxins. In this study, cDNA encoding two subtypes of human interferon-alpha2b and 8 (HuIFN-alpha2b and HuIFN-alpha8) were introduced into potato plants (Solanum tuberosum) using Agrobacterium-mediated transformation. Transcription and translation of the inserted HuIFN-alpha cDNA were confirmed by Northern blot analysis and ELISA, respectively. Bioactivity of the products was assayed by inhibition of vesicular stomatitis virus (VSV) replication on a human amniotic cell line. However, because of the presence of substances in potato tissue extracts that were toxic to animal cells, successful demonstration of IFN bioactivity in the transformants was achieved only after removal of such substances by dialysis. The maximum level of IFN activity in plant extracts was 560 IU/g of tissue. These results indicated that the HuIFN-alpha gene introduced into the potato plant was correctly translated and transcribed in plant cells. This report for the first time shows that biologically active animal cytokines with potential pharmaceutical applications could be expressed in transgenic potato plants.

Acquired storage-pool disorders occurring late after allogeneic bone marrow transplantation: partial activation of platelets in asymptomatic patients

Bone marrow transplantation (BMT) may be complicated by coagulation abnormalities. The present study evaluated whether platelets might be activated in patients who had undergone BMT without significant coagulopathy. The patients selected had received allogeneic BMTs a median of 39 months before the study (range, 11-124 months) and had not received cyclosporine, FK506 (tacrolimus), or other medication affecting cyclo-oxygenase for at least 3 months prior to the collection of blood samples. Furthermore, patients had platelet counts greater than 100 x 10(9) cells/L and normal serum creatinine levels. Twenty-five healthy volunteers acted as controls. Platelet aggregation studies and a mepacrine assay of platelets showed abnormal aggregation and decreased staining in some patients. The platelet storage-pool adenosine 5'-triphosphate (ATP) level in 15 patients after BMT was 0.45+/-0.24 micromol per 10(11) platelets, whereas the level in 18 controls was 1.03+/-0.36 micromol per 10(11) platelets (P = .00078). The total ATP levels of platelets in patients and controls were 4.33+/-1.14 and 5.63+/-1.51 micromol per 10(11) platelets, respectively (P = .016). With the exception of 1 patient, plasma levels of thrombomodulin and von Willebrand factor were all within the normal range. The average plasma level of 11-dehydrothromboxane B2 was significantly increased in 15 patients after BMT compared with controls, 20.6+/-8.2 and 10.3+/-1.2 pg/mL, respectively (P = .0004). These findings suggest a long-term process of platelet activation in patients after BMT and, following the cessation of cyclosporine, development of acquired storage-pool disorder of platelets.

cDNA cloning, characterization and vaccine effect analysis of Haemaphysalis longicornis tick saliva proteins

Immunological control of ticks is currently the only sustainable and practical alternative method to the current use of acaricides which has serious limitations. The success of this method is dependent upon identification and cloning of potential tick vaccine antigens. We used a combination of immuno-screening of an adult tick cDNA library as well as the 3 and 5 rapid amplification of cDNA ends to clone two cDNAs, encoding tick saliva proteins from Haemaphysalis longicornis. The two cDNAs herein named HL 34 and 35 are 1000 bp each and encode polypeptides with 292 and 321 amino acid residues respectively. Northern blotting analysis of total RNA from ticks at different feeding stages revealed that expression of both HL 34 and HL35 mRNAs is induced during the slow feeding phase. We speculate that the functions of both genes are closely associated with blood feeding. Expression analysis by RT-PCR showed that both genes are expressed in other tick organs in addition to salivary glands. Recombinant HL 34 was successfully expressed in Escherichia coli and its suitability as a tick vaccine antigen was analyzed in rabbits. We propose that rHL34 could be a useful component of a cocktail tick vaccine.

Host immune responses in the course of bovine leukemia virus infection

Bovine leukemia virus (BLV) is a type C retrovirus infecting bovine B cells and causing enzootic bovine leukosis. Since it takes long periods to develop the disease, it is believed that BLV and host immune responses are closely related. In this review, the accumulated data showing close relationship between BLV and host immune responses are summarized in 4 sections. First, we discuss the role of cell-mediated immunity in protecting hosts from BLV infection. Second, several reports showing the relationship between the disease progression and the change of cytokine profiles are summarized. In the third section, we have focused on tumor necrosis factor alpha (TNFalpha) and its two types of receptors, and the possible involvement of TNFalpha in the BLV-induced leukemogenesis is discussed. The expression of TNFalpha has been shown to be regulated by major histocompatibility complex (MHC) haplotype. The resistance to BLV infection is supposed to be established by some innate factors, which are closely related to MHC haplotype. Finally, we propose that a breeding strategy based on the MHC haplotype could be a good approach to control BLV infection. This review includes some recent data from us and other groups.

Evaluation of various imaging methods in the differential diagnosis of intraductal papillary-mucinous tumor (IPMT) of the pancreas

BACKGROUND/AIMS

IPMT (intraductal papillary-mucinous tumor) of the pancreas has unique clinicopathological characteristics. The lesions which show characteristic clinical features of IPMT exhibit a wide spectrum of histological types ranging from atypical hyperplasia to invasive cancer. Therefore, surgical treatment cannot be recommended for all patients with IPMT. It is necessary to assess the malignant potential of IPMT in individual patients in order to select an appropriate approach. The aim of this study was to evaluate the effectiveness of endoscopic ultrasonography and intraductal ultrasonography as compared with ultrasonography and computed tomography for this purpose.

METHODOLOGY

Ultrasonography, computed tomography, endoscopic ultrasonography and intraductal ultrasonography were performed in 49 cases of IPMT (atypical hyperplasia 7, adenoma 23, noninvasive 7 and invasive adenocarcinoma 12). On the basis of the histopathological analysis of another 28 cases of resected IPMT specimens, criteria for differential diagnosis by imaging modalities were defined as follows: Nonneoplastic lesion (atypical hyperplasia): no wall thickening or nodule; noninvasive IPMT (adenoma and intraductal carcinoma): a nodule or wall thickening is present; and invasive IPMT with pancreatic parenchymal invasion: a mass with a heterogenous pattern or interruption of the pancreatic duct wall by the mass.

RESULTS

The diagnostic accuracy rate for differentiating nonneoplastic lesion noninvasive IPMT, and invasive IPMT was 33% by ultrasonography, 38% by computed tomography, 77% by endoscopic ultrasonography, and 67% by intraductal ultrasonography. Sensitivity, specificity and accuracy rates for differentiating neoplastic and nonneoplastic IPMT by ultrasonography was 33%, 100%, 42%, by computed tomography 36%, 100%, 44%, by endoscopic ultrasonography 90%, 71%, 88%, by intraductal ultrasonography 94%, 29%, 84%, respectively. Sensitivity, specificity and accuracy rates for differentiating invasive and noninvasive IPMT by ultrasonography was 25%, 100%, 80%, by computed tomography 33%, 100%, 83%, by endoscopic ultrasonography 55%, 97%, 88%, by intraductal ultrasonography 56%, 91%, 84%, respectively. Diagnostic accuracy for invasive IPMT except minimally invasive cases by endoscopic ultrasonography and intraductal ultrasonography was 80%, based on the results of the examination which demonstrated a higher grade lesion.

CONCLUSIONS

With these criteria, ultrasonography and computed tomography showed high specificity, but low sensitivity for the differential diagnosis of neoplastic/nonneoplastic and invasive/noninvasive IPMT. However, endoscopic ultrasonography and intraductal ultrasonography had high sensitivity and diagnostic accuracy for the differential diagnosis of neoplastic/nonneoplastic lesions. Combination of endoscopic ultrasonography and intraductal ultrasonography showed a high accuracy rate in the diagnosis of invasive IPMT. Thus endoscopic ultrasonography and intraductal ultrasonography contributed significantly to the choice of the treatment for IPMT.

Superficial esophageal carcinoma: an in vitro study of high-resolution MR imaging at 1.5T

The purpose of this study was to determine the diagnostic accuracy of high-resolution MR imaging at 1.5T for evaluating the mural invasion of superficial esophageal carcinoma. Forty-one esophageal specimens taken from patients suspected of having superficial carcinoma were studied using a 1.5T MR system with a surface coil. Spin-echo MR images were obtained with a field of view of 50mm, matrix of 256 x 256, and section thickness of 2mm (voxel size = 0.08 mm3). MR findings were compared with histopathologic findings. T2-weighted images clearly depicted the normal esophageal wall as consisting of 8 layers. In 39 (95%) of 41 carcinomas, the depth of mural invasion determined by MR imaging correlated well with that determined with histopathologic examination. The MR-based stage was higher in 2 (5%) cases than the histopathologic stage. High-resolution MR imaging at 1.5T shows a high diagnostic accuracy for evaluating the mural invasion of superficial esophageal carcinoma, thus potentially enabling preoperative histopathologic staging.

Characterization of two cDNAs encoding serine proteinases from the hard tick Haemaphysalis longicornis

Host vaccination against tick infestation is at present the most practical and sustainable alternative tick control method to the current acaricide use which has serious limitations. However the success of this approach to control ticks depends upon the identification of target vaccine antigens. Members of the serine proteinase gene family may represent an interesting group of proteins to target as candidate antigens because of their involvement in regulation of many physiological functions and development processes in a wide range of organisms. We used RT-PCR with the 3' and 5' RACE to clone two cDNAs encoding full-length serine proteinases from the hard tick, Haemaphysalis longicornis. RT-PCR degenerate primers were designed from amino acid sequences surrounding active sites, His(57) and Ser(195) conserved among most known serine proteinase. Gene specific primers designed from nucleotide sequences of the RT-PCR products were used to prime the 3' and 5' RACE. Southern blotting analysis showed that both HLSG-1 and -2 are single copy. The 2 cDNAs, HLSG-1 and -2 are 1.2 and 1.0 kb long in size with open reading frames encoding polypeptides with 37.7 and 31.2 kDa predicted molecular mass respectively. Northern blotting analysis of total RNA from unfed and partially fed whole ticks showed that the expression of mRNAs for both HLSG-1 and -2 was induced by blood feeding. Expression analysis by RT-PCR showed that both HLSG-1 and -2 are expressed in other tick organs in addition to salivary glands and midguts. The 6 serine proteinase consensus cyteine residues are well conserved in both HLSG-1 and -2. We have discussed our findings with respect to tick vaccine development research.

Effects of genotypic differences in CYP2C19 status on cure rates for Helicobacter pylori infection by dual therapy with rabeprazole plus amoxicillin

Rabeprazole is a potent proton pump inhibitor and is mainly reduced to thioether rabeprazole by a non-enzymatic pathway and partially metabolized to demethylated rabeprazole by CYP2C19 in the liver. We intended to determine a cure rate for Helicobacter pylori infection by dual rabeprazole/amoxicillin therapy in relation to CYP2C19 genotype status prospectively. Ninety-seven patients with gastritis and H. pylori infection completed the dual therapy with 10 mg of rabeprazole bid and 500 mg of amoxicillin tid for 2 weeks. At 1 month after treatment, cure of H. pylori infection was assessed on the basis of histology, a rapid urease test, culture, polymerase chain reaction (PCR), and 13C-urea breath test. CYP2C19 genotype status was determined by a PCR-restriction fragment length polymorphism method. Of the 97 patients, 33 were homozygous extensive metabolizers (homEM), 48 were heterozygous extensive metabolizers (hetEM), and 16 were poor metabolizers (PM). Cure of H. pylori infection was achieved in 79 of the 97 patients (81.4%, 95%CI = 71.9-88.7). Significant differences in cure rates among the homEM, hetEM, and PM groups were observed; 60.6% (95%CI = 42.1-77.3), 91.7% (95%CI = 80.0-97.7), and 93.8% (95%CI = 69.8-99.8), respectively (P = 0.0007). Twelve patients without cure after initial treatment (10 homEMs and 2 hetEMs) were successfully retreated with rabeprazole 10 mg q.i.d. and amoxicillin 500 mg q.i.d. for 2 weeks. The cure rates for H. pylori infection by dual rabeprazole/amoxicillin therapy depended on the CYP2C19 genotype status. This dual therapy appears to be effective for hetEM and PM patients. However, high dose dual rabeprazole/amoxicillin therapy was effective even for homEM patients. Therefore, the genotyping test of CYP2C19 appears to be a clinically useful tool for the optimal dual treatment with rabeprazole plus amoxicillin.

Effect of additional chromosomal abnormalities in acute promyelocytic leukemia treated with all-trans-retinoic acid: a report of 17 patients

Seventeen cases of acute promyelocytic leukemia (APL) treated with all-trans-retinoic acid (ATRA) and combination chemotherapy at Tokyo Metropolitan Komagome Hospital between 1992 and 1999 were reviewed, and divided into 2 karyotype-based cytogenetic groups. One group comprised 7 patients with either the typical t(15;17) alone or a normal karyotype, and the other group comprised 10 patients with additional karyotypic abnormalities. No patient had received prior chemotherapy or irradiation, and no cases were complicated by a history of myelodysplastic syndrome before the diagnosis of APL. There were no significant differences in clinical characteristics at disease presentation. Complete remission was achieved in all 17 patients and karyotypes of bone marrow cells normalized in all cases. No differences were found in relapse rate, overall survival, or disease-free survival between the 2 groups. The analysis did not reveal any significant effect of additional chromosomal abnormalities on the prognosis of APL patients undergoing treatment with ATRA. However, a small number of patients were assessed in this study, and further cumulative studies are needed.

Association of polymorphisms in the beta-2 and beta-3 adrenoceptor genes with risk of colorectal cancer in Japanese

BACKGROUND

The adrenergic receptor system is involved in thermogenesis and in the activation of lipid mobilization in fat cells, and polymorphisms in the beta-2 and beta-3 adrenoceptor genes (BAR2 and BAR3) have been reported to be associated with obesity and insulin resistance. To examine links between polymorphisms in these genes and the risk of colorectal cancer in Japanese, we conducted the present hospital-based case-referent study.

METHODS

Mutations of the BAR2 gene at codon 27 (Gln27Glu) and of the BAR3 gene at codon 64 (Trp64Arg) were examined in 131 patients with colorectal cancer (cases) and in 239 cancer-free referents. We also collected information on environmental factors, using a questionnaire approach. Odds ratios (ORs) were estimated with an unconditional logistic model, after adjustment for potential confounding factors.

RESULTS

The proportional distribution of the mutations in BAR2 and BAR3 did not differ between cases and referents. Analysis of a subgroup with a higher body mass index showed that the Trp64Arg variant increased the OR (2.63; 95% confidence interval, 1.13-6.11) for colon cancer, but not for rectal cancer, compared with the Trp64 genotype. Altered ORs for colon and rectal cancers with the Gln27Glu variant were not observed in either the subgroup with the lower body mass index or the subgroup with the higher body mass index.

CONCLUSION

These findings suggest that the BAR3 polymorphism may alter the susceptibility to colon cancer risk in obese subjects. To confirm this finding, a further study with a larger number of subjects is now required.

Second allogeneic peripheral blood stem cell transplantation with fludarabine-based low-intensity conditioning regimen for relapsed myelodysplastic syndrome after allogeneic bone marrow transplantation

We describe the case of a 51-year-old patient with relapsed myelodysplastic syndrome after allogeneic bone marrow transplantation (BMT), who underwent allogeneic peripheral blood stem cell transplantation (PBSCT) after conditioning with a novel regimen consisting of fludarabine, busulfan, and antithymocyte globulin. The second PBSCT was performed early, at 3 months after the initial allogeneic BMT, but it was well tolerated and complete hematologic remission was documented. The patient did not experience any early transplantation-related organ toxicity but died from opportunistic infection 6 months after the second transplantation. Our experience suggests that this novel regimen may induce remission and could be offered to patients relapsing after the first transplantation; however, the fludarabine-containing regimen might be accompanied by profound immunosuppression.

Adenovirus is a key pathogen in hemorrhagic cystitis associated with bone marrow transplantation

Late-onset hemorrhagic cystitis (HC) is a well-known complication of bone marrow transplantation (BMT) that is mainly attributed to infection with BK virus (BKV) and adenovirus (AdV). From 1986 through 1998, 282 patients underwent BMT, and 45 of them developed HC. Urine samples tested positive for AdV in 26 patients, of which 22 showed virus type 11. Among patients who underwent allogeneic BMT, logistic regression analysis revealed acute graft-versus-host disease (grade, > or = 2) to be the most significant predictive factor for HC (P < .0001). In addition, a total of 193 urine samples regularly obtained from 26 consecutive patients who underwent allogeneic BMT were examined for BKV, JC virus (JCV), and AdV by means of polymerase chain reaction. Of patients without HC, approximately 30% of the specimens tested positive for BKV (58 samples) and JCV (55 samples), whereas 5 (3%) tested positive for AdV. Of the 3 samples obtained from patients with HC, the numbers of positive results for BKV, JCV, and AdV were 3, 1, and 1, respectively; the numbers of positive results increased to 14 of 17, 9 of 17, and 10 of 17, respectively, when we added another 14 samples obtained from 14 patients with HC (P < .0001, P = .026, and P < .0001, respectively). In conclusion, there was significant correlation between AdV and HC in the patients we studied.

Identification of liver X receptor-retinoid X receptor as an activator of the sterol regulatory element-binding protein 1c gene promoter

In an attempt to identify transcription factors which activate sterol-regulatory element-binding protein 1c (SREBP-1c) transcription, we screened an expression cDNA library from adipose tissue of SREBP-1 knockout mice using a reporter gene containing the 2.6-kb mouse SREBP-1 gene promoter. We cloned and identified the oxysterol receptors liver X receptor (LXRalpha) and LXRbeta as strong activators of the mouse SREBP-1c promoter. In the transfection studies, expression of either LXRalpha or -beta activated the SREBP-1c promoter-luciferase gene in a dose-dependent manner. Deletion and mutation studies, as well as gel mobility shift assays, located an LXR response element complex consisting of two new LXR-binding motifs which showed high similarity to an LXR response element recently found in the ABC1 gene promoter, a reverse cholesterol transporter. Addition of an LXR ligand, 22(R)-hydroxycholesterol, increased the promoter activity. Coexpression of retinoid X receptor (RXR), a heterodimeric partner, and its ligand 9-cis-retinoic acid also synergistically activated the SREBP-1c promoter. In HepG2 cells, SREBP-1c mRNA and precursor protein levels were induced by treatment with 22(R)-hydroxycholesterol and 9-cis-retinoic acid, confirming that endogenous LXR-RXR activation can induce endogenous SREBP-1c expression. The activation of SREBP-1c by LXR is associated with a slight increase in nuclear SREBP-1c, resulting in activation of the gene for fatty acid synthase, one of its downstream genes, as measured by the luciferase assay. These data demonstrate that LXR-RXR can modify the expression of genes for lipogenic enzymes by regulating SREBP-1c expression, providing a novel link between fatty acid and cholesterol metabolism.

Asialoglycoprotein receptor deficiency in mice lacking the major receptor subunit. Its obligate requirement for the stable expression of oligomeric receptor

The asialoglycoprotein receptor is an abundant hetero-oligomeric endocytic receptor that is predominantly expressed on the sinusoidal surface of the hepatocytes. A number of physiological and pathophysiological functions have been ascribed to this hepatic lectin (HL), the removal of desialylated serum glycoproteins and apoptotic cells, clearance of lipoproteins, and the sites of entry for hepatotropic viruses. The assembly of two homologous subunits, HL-1 and HL-2, is required to form functional, high affinity receptors on the cell surface. However, the importance of the individual subunits for receptor transport to the cell surface is controversial. We have previously generated HL-2-deficient mice and showed that the expression of HL-1 was significantly reduced, and the functional activity as the asialoglycoprotein receptor was virtually eliminated. However, we failed to detect phenotypic abnormalities. To explore the significance of the major HL-1 subunit for receptor expression and function in vivo, we have disrupted the HL-1 gene in mice. Homozygous HL-1-deficient animals are superficially normal. HL-2 expression in the liver is virtually abrogated, indicating that HL-1 is strictly required for the stable expression of HL-2. Although these mice are almost unable to clear asialo-orosomucoid, a high affinity ligand for asialoglycoprotein receptor, they do not accumulate desialylated glycoproteins or lipoproteins in the plasma.

N-WASP, WAVE and Mena play different roles in the organization of actin cytoskeleton in lamellipodia

WASP- and Ena/VASP-family proteins have been reported to regulate the cortical actin cytoskeleton as downstream effectors of the Ρ-family small G-proteins Rac and Cdc42, but their functions are little understood. We observed the localization of the WASP family proteins, N-WASP and WAVE, and the Ena/VASP family protein, Mena, in protruding lamellipodia. Rat fibroblast cell line 3Y1 protruded lamellipodia on poly-L-lysine-coated substrate without any trophic factor. N-WASP and Cdc42 were concentrated along the actin filament bundles of microspikes but not at the tips. By immunofluorescence and immunoelectron microscopy, both WAVE and Mena were observed to localize at the lamellipodium edge. Interestingly, Mena tended to concentrate at the microspike tips but WAVE did not. At the edge of the lamellipodium, the correlation between the fluorescence from Mena and actin filaments stained with the specific antibody and rhodamine-phalloidin, respectively, was much higher than that between WAVE and actin filament. The Ena/VASP homology 2 (EVH2) domain of avian Ena, an avian homolog of Mena, was localized to the lamellipodium edge and concentrated at the tip of microspikes. The SCAR homology domain (SHD) of human WAVE was distributed along the lamellipodium edge. These results indicate that N-WASP, WAVE and Mena have different roles in the regulation of the cortical actin cytoskeleton in the protruding lamellipodium. WAVE and Mena should be recruited to the lamellipodium edge through SHD and the EVH2 domain, respectively, to regulate the actin polymerization near the cell membrane. N-WASP should regulate the formation of the actin filament bundle in addition to activating Arp2/3 complex in lamellipodium under the control of Cdc42.

M100907, a selective 5-HT(2A) receptor antagonist, attenuates phencyclidine-induced Fos expression in discrete regions of rat brain

5-HT and dopamine receptor antagonists have become widely used as atypical antipsychotics. Although 5-HT(2A) receptor antagonistic activity is thought to contribute to the atypical aspects of these agents, the precise mechanism remains unknown. M100907 (R(+)-alpha(2,3-dimethoxyphenyl)-1-[2(4-fluorophenyl)ethyl)]-4-piperidine -methanol), a selective 5-HT(2A) receptor antagonist, is reported to attenuate phencyclidine (PCP)-induced locomotion in rodents. For the purpose of identifying regions in which M100907 exerts its effect, we investigated the effects of M100907 on PCP-induced Fos expression in rat brain. PCP (5 mg/kg, subcutaneously, s.c.) induced Fos expression in the cingulate cortex area 3, the agranular insular cortex, the piriform cortex, the nucleus accumbens, the anterior paraventricular thalamic nucleus and the ventral lateral septal nucleus. Pretreatment with M100907 (0.5 mg/kg, s.c.) attenuated Fos expression induced by PCP in the nucleus accumbens core, the shell, the agranular insular cortex and the piriform cortex. M100907 did not induce Fos expression in any of the regions investigated including the dorsolateral caudate/putamen when given alone. These results indicate that 5-HT(2A) receptor antagonism attenuates Fos expression in a regionally specific manner in rat brain in the PCP model of psychosis.

Heparin inhibits plaque formation by cell-free Marek's disease viruses in vitro

The mechanisms of Marek's disease virus (MDV) entry to host cells have not yet been analyzed. Heparan sulfate (HS) on the cell surface serves as a receptor for several herpesviruses in mammalian species. In this study, we demonstrated that plaque formation by cell-free MDV is inhibited by the addition of soluble heparin to the cell culture. Moreover, pretreatment of susceptible cells, chicken embryo fibroblasts, with heparinase, partially reduced infectivity of the cell-free MDV. From these results, it was suggested that the MDV entry, at least in the case of cell-free MDV, is dependent on the presence of cell surface glycosaminoglycans, principally HS.

Myosin light chain kinase regulates capacitative ca(2+) entry in human monocytes/macrophages

Monocytes/macrophages are present in all stages of atherosclerosis. Although many of their activities depend to various extents on changes in intracellular Ca(2+) concentration ([Ca(2+)](i)), mechanisms regulating [Ca(2+)](i) in these cells remain unclear. We aimed to explore the role of myosin light chain kinase (MLCK) in Ca(2+) signaling in freshly isolated human monocytes/macrophages. Large capacitative Ca(2+) entry (CCE) was observed under fura 2 fluoroscopy in human monocytes/macrophages treated with thapsigargin and cyclopiazonic acid. ML-9 and wortmannin, 2 structurally different inhibitors of MLCK, dose-dependently (1 to 100 micromol/L) prevented CCE and completely did so at 100 micromol/L, whereas inhibitors of tyrosine kinase and protein kinase C had only partial effects. Western blotting showed that thapsigargin significantly caused myosin light chain phosphorylation, which was almost completely blocked by ML-9 (100 micromol/L) and wortmannin (100 micromol/L). ML-9 also dose-dependently (1 to 100 micromol/L) inhibited this phosphorylation, which was well correlated with its inhibition of CCE. Transfection with MLCK antisense completely prevented CCE in response to thapsigargin and cyclopiazonic acid, whereas MLCK sense had no effect. These data strongly indicate that MLCK regulates CCE in human monocytes/macrophages. The study suggests a possible involvement of MLCK in many Ca(2+)-dependent activities of monocytes/macrophages.

Phosphorylation of cofilin by LIM-kinase is necessary for semaphorin 3A-induced growth cone collapse

Semaphorin 3A is a chemorepulsive axonal guidance molecule that depolymerizes the actin cytoskeleton and collapses growth cones of dorsal root ganglia neurons. Here we investigate the role of LIM-kinase 1, which phosphorylates an actin-depolymerizing protein, cofilin, in semaphorin 3A-induced growth cone collapse. Semaphorin 3A induced phosphorylation and dephosphorylation of cofilin at growth cones sequentially. A synthetic cell-permeable peptide containing a cofilin phosphorylation site inhibited LIM-kinase in vitro and in vivo, and essentially suppressed semaphorin 3A-induced growth cone collapse. A dominant-negative LIM kinase, which could not be activated by PAK or ROCK, suppressed the collapsing activity of semaphorin 3A. Phosphorylation of cofilin by LIM-kinase may be a critical signaling event in growth cone collapse by semaphorin 3A.