Phylogenetic Analysis of a Privately-owned Korean Native Chicken Population Using mtDNA D-loop Variations

The use of Korean native chicken is increasing, and the discovery of new genetic resources is very important from both economic and genetic conservation points of view. In this study, mtDNA D-loop sequences from 272 privately-owned Korean native chickens from a Hyunin farm were investigated. Seventeen nucleotide substitutions were identified from the sequence analysis and they were classified as 6 haplotypes. Previously investigated haplotypes in five Korean native chicken populations have been compared with the Hyunin chicken population. The results indicated that two haplotypes, H10 and H15, in the Hyunin chicken population were not previously identified in other Korean native chicken populations, representing 33.09% (90/272) and 1.1% (3/272) of the Hyunin population, respectively. On the other hand, four other haplotypes were identical to those of a previous study of Korean native chicken populations. This result is indicative of conservation strategies of Hyunin chicken populations for expanding the genetic diversity in the Korean native chicken population.

Discrimination of korean native chicken lines using fifteen selected microsatellite markers

In order to evaluate the genetic diversity and discrimination among five Korean native chicken lines, a total of 86 individuals were genotyped using 150 microsatellite (MS) markers, and 15 highly polymorphic MS markers were selected. Based on the highest value of the number of alleles, the expected heterozygosity (He) and polymorphic information content (PIC) for the selected markers ranged from 6 to 12, 0.466 to 0.852, 0.709 to 0.882 and 0.648 to 0.865, respectively. Using these markers, the calculated genetic distance (Fst), the heterozygote deficit among chicken lines (Fit) and the heterozygote deficit within chicken line (Fis) values ranged from 0.0309 to 0.2473, 0.0013 to 0.4513 and -0.1002 to 0.271, respectively. The expected probability of identity values in random individuals (PI), random half-sib (PI half-sibs ) and random sibs (PI sibs ) were estimated at 7.98×10(-29), 2.88×10(-20) and 1.25×10(-08), respectively, indicating that these markers can be used for traceability systems in Korean native chickens. The unrooted phylogenetic neighbor-joining (NJ) tree was constructed using 15 MS markers that clearly differentiated among the five native chicken lines. Also, the structure was estimated by the individual clustering with the K value of 5. The selected 15 MS markers were found to be useful for the conservation, breeding plan, and traceability system in Korean native chickens.

Investigation of MC1R SNPs and Their Relationships with Plumage Colors in Korean Native Chicken

The melanocortin 1 receptor (MC1R) gene is related to the plumage color variations in chicken. Initially, the MC1R gene from 30 individuals was sequenced and nine polymorphisms were obtained. Of these, three and six single nucleotide polymorphisms (SNPs) were confirmed as synonymous and nonsynonymous mutations, respectively. Among these, three selected SNPs were genotyped using the restriction fragment length polymorphism (RFLP) method in 150 individuals from five chicken breeds, which identified the plumage color responding alleles. The neighbor-joining phylogenetic tree using MC1R gene sequences indicated three well-differentiated different plumage pigmentations (eumelanin, pheomelanin and albino). Also, the genotype analyses indicated that the TT, AA and GG genotypes corresponded to the eumelanin, pheomelanin and albino plumage pigmentations at nucleotide positions 69, 376 and 427, respectively. In contrast, high allele frequencies with T, A and G alleles corresponded to black, red/yellow and white plumage color in 69, 376 and 427 nucleotide positions, respectively. Also, amino acids changes at position Asn23Asn, Val126Ile and Thr143Ala were observed in melanin synthesis with identified possible alleles, respectively. In addition, high haplotype frequencies in TGA, CGG and CAA haplotypes were well discriminated based on the plumage pigmentation in chicken breeds. The results obtained in this study can be used for designing proper breeding and conservation strategies for the Korean native chicken breeds, as well as for the developing breed identification markers in chicken.

Forming mechanism of the bipolar resistance switching in double-layer memristive nanodevices

To initiate resistance switching phenomena, it is usually necessary to apply a strong electric field to a sample. This forming process poses very serious obstacles in real nanodevice applications. In unipolar resistance switching (URS), it is well known that the forming originates from soft dielectric breakdown. However, the forming in bipolar resistance switching (BRS) is poorly understood. In this study, we investigated the forming processes in Pt/Ta₂O₅/TaOx/Pt and Pt/TaOx/Pt nanodevices, which showed BRS and URS, respectively. By comparing the double- and single-layer systems, we were able to observe differences in the BRS and URS forming processes. Using computer simulations based on an 'interface-modified random circuit breaker network model', we could explain most of our experimental observations. This success suggests that the BRS forming in our Pt/Ta₂O₅/TaOx/Pt double-layer system can occur via two processes, i.e., polarity-dependent resistance switching in the Ta₂O₅ layer and soft dielectric breakdown in the TaOx layer. This forming mechanism can be used to improve the performance of BRS devices. For example, we could improve the endurance properties of Pt/Ta₂O₅/TaOx/Pt cells by using a small forming voltage.

Spectrum of MR imaging findings in Wernicke encephalopathy: are atypical areas of involvement only present in nonalcoholic patients?

BACKGROUND AND PURPOSE

Although MR imaging is considered the most effective method to confirm a diagnosis of WE, MR imaging studies designed to distinguish WE between NA and AL patients have yielded controversial results. The purpose of this study was to determine potential differences in MR imaging features between AL and NA patients with WE and to compare neurologic symptoms with MR imaging findings.

MATERIALS AND METHODS

This retrospective study included 24 consecutive patients (male/female, 15:9; mean age, 54 years) diagnosed with WE in a university hospital (AL = 13, NA = 11). Clinical manifestations and MR imaging findings between AL and NA patients were evaluated. Classic WE symptom triad and consciousness level and MR imaging findings were scored and compared with each other. Statistical analyses were performed with χ(2), Fisher exact, and Spearman tests.

RESULTS

No differences were observed regarding the areas of hyperintense signal intensity on FLAIR imaging and enhancement of the mammillary bodies between AL and NA patients (P > .05). Frequent sites of involvement were the medial thalami (86%), dorsal medulla (82%), tectal plate (77%), and the periaqueductal gray matter (75%). A positive association was found between the consciousness levels of the patients and the involvement of atypical sites (P = .01). Only 4 of the 24 patients (17%) had all 3 symptoms of the classic WE symptom triad.

CONCLUSIONS

MR imaging features of WE may not be different between AL and NA patients. The medulla is 1 of the most frequently involved sites, and consciousness level is also associated with atypical site involvement.

An Uncommon Arteriovenous Fistula Resulting from Haemodialysis Catheterization despite Applying Ultrasound Guidance: Malposition of Catheter into Right Subclavian Artery

Ultrasound-guided central venous catheterization could reduce the complication rate and increase first time success rate. However, without substantial experience and caution, it could lead to serious complications. We presented a rare case of malposition of the temporary haemodialysis catheter into the right subclavian artery with arteriovenous fistula after real-time 2D ultrasound-guided catheterization into right internal jugular vein. After the occurrence of this complication, we learned that emergency physicians should confirm the position of end portion of the catheter within the target vessel's lumen even when the catheterization was done with real-time 2D ultrasound guidance.

Scaling theory for unipolar resistance switching

We investigate a reversible percolation system showing unipolar resistance switching in which percolating paths are created and broken alternately by the application of an electric bias. Owing to the dynamical changes in the percolating paths, different from those in classical percolating paths, a detailed understanding of the structure is demanding and challenging. Here, we develop a scaling theory that can explain the transport properties of these conducting paths; the theory is based on the fractal geometry of a percolating cluster. This theory predicts that two scaling behaviors emerge, depending on the topologies of the conducting paths. We confirm these theoretical predictions experimentally by observing material-independent universal scaling behaviors in unipolar resistance switching.

The control of cell adhesion and viability by zinc oxide nanorods

The ability to control the behavior of cells that interact with implanted biomaterials is desirable for the success of implanted devices such as biosensors or drug delivery devices. There is a need to develop materials that can limit the adhesion and viability of cells on implanted biomaterials. In this study, we investigated the use of zinc oxide (ZnO) nanorods for modulating the adhesion and viability of NIH 3T3 fibroblasts, umbilical vein endothelial cells, and capillary endothelial cells. Cells adhered far less to ZnO nanorods than the corresponding ZnO flat substrate. The few cells that adhered to ZnO nanorods were rounded and not viable compared to the flat ZnO substrate. Cells were unable to assemble focal adhesions and stress fibers on nanorods. Scanning electron microscopy indicated that cells were not able to assemble lamellipodia on nanorods. Time-lapse imaging revealed that cells that initially adhered to nanorods were not able to spread. This suggests that it is the lack of initial spreading, rather than long-term exposure to ZnO that causes cell death. We conclude that ZnO nanorods are potentially useful as an adhesion-resistant biomaterial capable of reducing viability in anchorage-dependent cells.

GaN, ZnO and InN nanowires and devices

A brief review is given of recent developments in wide bandgap semiconductor nanowire synthesis and devices fabricated on these nanostructures. There is strong interest in these devices for applications in UV detection, gas sensors and transparent electronics.

The prevalence of the mitochondrial DNA 16189 variant in non-diabetic Korean adults and its association with higher fasting glucose and body mass index

AIMS

To evaluate the prevalence of the 16189 variant of mitochondrial DNA in Korean adults and its association with insulin resistance.

METHODS

We investigated 160 non-diabetic subjects from a community-based diabetes survey conducted in Yonchon County, Korea in 1993. We extracted the DNA from peripheral blood and examined the 16189 variant by polymerase chain reaction and restrictive enzyme digestion. We compared body mass index (BMI), blood pressure, fasting plasma glucose, 2-h plasma glucose after 75 g glucose load, fasting insulin, cholesterol, and homeostasis model assessment of insulin resistance and beta-cell function between the subjects with 16189 variant and wild type.

RESULTS

The prevalence of the 16189 variant in Korean adults was 28.8% (46 of 160). Subjects with the 16189 variant had higher fasting glucose and BMI than those with wild type, but fasting insulin, homeostasis model assessment of insulin resistance and beta-cell function, cholesterol, and blood pressure were not different between two groups.

CONCLUSION

Our results provide evidence for an association of a frequent mitochondrial polymorphism with higher fasting glucose and the risk factors of diabetes mellitus.

A survey of heterobasidiomycetous yeasts for the presence of the genes homologous to virulence factors of Filobasidiella neoformans, CNLAC1 and CAP59

Among species of the heterobasidiomycetous yeasts, Filobasidiella neoformans is the only serious pathogen that causes fatal infections in both immunocompromised as well as immunocompetent patients. Three phenotypic characteristics, including growth at 37 degrees C, extracellular polysaccharide capsule and laccase activity, of F. neoformans are known to play major roles in the pathogenicity of the fungus. Several CAP genes involved in polysaccharide capsule formation, as well as the CNLAC1 gene encoding a laccase, have previously been cloned and characterized. To analyse the presence of these Cryptococcus neoformans virulence factors in other heterobasidiomycetous yeasts, numerous species of heterobasidiomycetous yeasts were screened for the presence of laccase activity and a polysaccharide capsule. Species exhibiting laccase activity and possessing a glucuronoxylomannan (GXM) capsule were screened for homologues of both the CAP59 gene and the CNLAC1 gene of F. neoformans. Southern blots of genomic DNA from GXM capsule-producing species exhibited no discernible hybridization to the CAP59 DNA sequence except for the two varieties of F. neoformans and Cryptococcus podzolicus. Although discernible, the hybridization band observed with the DNA of C. podzolicus was faint. Oligonucleotide primers constructed using the CAP59 gene sequence also failed to yield PCR products from DNAs of these yeasts except for the two varieties of F. neoformans. These results, coupled with the absence of a CAP59 homologue in the database, suggested the CAP59 gene to be unique to F. neoformans. C. podzolicus was the only species besides F. neoformans that possessed a capsule and expressed strong laccase activity on various media containing phenolic compounds. A CNLAC1 homologue was isolated from C. podzolicus while it was not detected in the species producing beige to faint tan colonies on media with phenolic compounds. Compared to the CNLAC1 sequence of four serotypes of F. neoformans, the CNLAC1 homologue of C. podzolicus showed the highest homology to that of serotype B/C strains and the lowest homology to that of serotype A strains.

Inhibitory effects of anti-inflammatory drugs on interleukin-6 bioactivity

Interleukin-6 (IL-6) is known as a proinflammatory cytokine involved in immune response, inflammation, and hematopoiesis. Inhibitory effects of anti-inflammatory drugs on IL-6 bioactivity using IL-6-dependent hybridoma have been evaluated. Three out of 16 nonsteroidal anti-inflammatory drugs (NSAIDs) showed IC50 values of less than 100 microM, which were in the order of oxyphenylbutazone hydrate (IC50=7.5 microM)>meclofenamic acid sodium salt (31.9 microM)>sulindac (74.9 microM). Steroidal anti-inflammatory drugs (SAIDs) exhibited significant inhibitory effects at 100 microM on the IL-6 bioactivity, and their inhibitory potencies were in the order of budesonide (IC50=2.2 microM)>hydrocortisone 21-hemisuccinate (6.7 microM), prednisolone (7.5 microM), betamethasone (10.9 microM)>dexamethasone (18.9 microM) and triamcinolone acetonide (24.1 microM). The results would provide an additional mechanism by which anti-inflammatory drugs display their anti-inflammatory and immunosuppressive effects at higher concentrations.

Enhanced susceptibility to Theiler's virus-induced demyelinating disease in perforin-deficient mice

Theiler's virus induces immune-mediated demyelinating disease similar to human MS in susceptible mice. Though the MHC class II-restricted T cell response is critical, susceptibility/resistance is also associated with a MHC class I haplotype. Here we report that perforin-deficient C57BL/6 mice (pKO) are susceptible to demyelination and develop clinical disease. The levels of primary demyelination, proliferation, Th1 responses, and viral load were also markedly enhanced. In addition, immunization of pKO mice with UV-inactivated virus further enhanced clinical incidence and accelerated the disease course. Thus, perforin is most likely involved in viral clearance, hence protection from the disease.

NMDA recepter-mediated neuroprotection by essential oils from the rhizomes of Acorus gramineus

Acori graminei Rhizoma (AGR) is shown to exhibit a number of pharmacological actions including sedation and anticonvulsive action. To further characterize its actions in the CNS, the present study evaluated the effects of essential oils (EO) from AGR on the excitotoxic neuronal cell death induced in primary rat cortical cell cultures. EO inhibited the glutamate-induced excitotoxicity in a concentration-dependent manner, with the IC50 of 0.241 mg/ml. EO exerted more potent neuroprotection against the toxicity induced by NMDA (IC50 = 0.139 mg/ml). In contrast, the AMPA-induced toxicity was not inhibited by EO. Receptor-ligand binding studies were performed to investigate the neuroprotective action mechanism. EO dramatically inhibited the specific bindings of a use-dependent NMDA receptorion channel blocker [3H]MK-801, indicating an NMDA receptor antagonist-like action. However, the bindings of [3H]MDL 105,519, a ligand selective for the glycine binding site of NMDA receptor, were not considerably inhibited. These results demonstrated that EO extracted from AGR exhibited neuroprotective effects on cultured cortical neurons through the blockade of NMDA receptor activity, and that the glycine binding site appeared not to be the major site of action.

Pathogenesis of virus-induced immune-mediated demyelination

Theiler's murine encephalomyelitis virus-induced demyelinating disease has been extensively studied as an attractive infectious model for human multiple sclerosis. Virus-specific inflammatory Th1 cell responses followed by autoimmune responses to myelin antigens play a crucial role in the pathogenic processes leading to demyelination. Antibody and cytotoxic T cells (CTL) responses to virus appears to be primarily protective from demyelinating disease. Although the role of Th1 and CTL responses in the induction of demyelinating disease is controversial, assessment of cytokines produced locally in the central nervous system (CNS) during the course of disease and the effects of altered inflammatory cytokine levels strongly support the importance of Th1 responses in this virus-induced demyelinating disease. Induction of various chemokines and cytokines in different glial and antigen presenting cells upon viral infection appears to be an important initiation mechanism for inflammatory Th1 responses in the CNS. Coupled with the initial inflammatory responses, viral persistence in the CNS may be a critical factor for sustaining inflammatory responses and consequent immune-mediated demyelinating disease.

Inhibition of excitotoxic neuronal death by methanol extract of Acori graminei rhizoma in cultured rat cortical neurons

Acori graminei rhizoma (AGR) are reported to exhibit a number of pharmacological actions in the central nervous system. The effects of the methanol extract of AGR on excitotoxic neuronal death were evaluated in the present study using cultured rat cortical neurons. Based on the phase-contrast microscopic examinations of cultures and lactate dehydrogenase activities measured in the culture media, the glutamate-induced excitotoxicity was significantly inhibited by the extract. The inhibitory action of the extract was more potent and selective for the N-methyl-D-aspartate (NMDA) receptor-mediated toxicity. The AGR extract competed with [3H]MDL 105,519 for the specific binding to the glycine site of the NMDA receptor with the IC(50) value of 164.7 microg/ml. Modulation of the NMDA receptor activity by the extract was determined using [3H]MK-801 binding studies. The reduction of the binding in the presence of the extract indicated the receptor inactivation by AGR. These results demonstrated that the methanol extract of AGR exhibited protective action against excitotoxic neuronal death, and that the neuroprotective action was primarily due to the blockade of NMDA receptor function by the interaction with the glycine binding site of the receptor.

Formation of mono-, bi-, tri-, and tetranuclear Ag(I) complexes of C3-symmetric tripodal benzimidazole ligands

The C3-symmetric tripodal ligand tris(2-benzimidazolylmethyl)amine (ntb) and its alkyl-substituted derivatives tris(N-R-benzimidazol-2-ylmethyl)amine (R = methyl, Mentb; R = ethyl, Etntb; R = propyl, Prntb) react with various silver(I) salts to afford mononuclear [Ag(Prntb)(CF3SO3)].0.25H2O, 1, binuclear [Ag2(Mentb)2](CF3SO3)2.H2O, 2, trinuclear [Ag3(Etntb)2](ClO4)3.CH3OH, 3, and tetranuclear [Ag4(ntb)2(CH3CN)2(CF3CO2)2](CF3CO2)2.2H2O, 4. All four complexes have been characterized by elemental analyses, IR spectroscopy, and X-ray crystallography. The Ag(I) ion in 1 is coordinated to the three imine nitrogen atoms of the Prntb ligand and one oxygen atom of the trifluoromethanesulfonate anion in a distorted tetrahedral environment. Dinuclear 2 has C2 symmetry with each Ag(I) atom trigonally coordinated by two arms of one Mentb and one arm of another. Trinuclear 3 has C3 symmetry with a Ag3 regular triangle sandwiched between a pair of Etntb ligands such that one arm of each ligand is involved in linear coordination about an Ag(I) atom. In the tetranuclear complex 4, two linearly coordinated Ag(I) atoms lying on the molecular C2 axis are bridged by a pair of ntb ligands and the remaining pendant arm of each ntb ligand is attached to another Ag(I) atom whose tetrahedral coordination sphere is completed by an acetonitrile molecule and a chelating trifluoroacetate anion. Complexes 2 and 3 may be regarded as an aggregation of two tridentate ligands by a silver dimer and a trinuclear cluster with weak Ag...Ag interactions, respectively, while in 4 the aggregation of two tripodal ligands by four Ag(I) ions affords a multicomponent internal cavity. The packing modes of complexes 1-3 are dominated by weak supramolecular pi...pi and CH...pi interactions. Hexagonal or square channels are generated in 1 and 2, and a honeycomb layer structure is formed in 3 with solvate molecules and counteranions occupying the voids. The crystal structure of 4 consists of a three-dimensional network consolidated by NH...O and OH...O hydrogen bonds.

The HCV core protein acts as a positive regulator of fas-mediated apoptosis in a human lymphoblastoid T cell line

Hepatitis C virus (HCV) is a major human pathogen causing mild to severe liver disease worldwide and is remarkably efficient at establishing persistent infections. Previously, we have shown that the core protein has an immunomodulatory function including the suppression of T lymphocyte responses to viral infection. To investigate the underlying mechanism for the role of core protein in immune modulation, we examined the effect of core on the sensitivity of the human T cell line, Jurkat, to Fas-mediated apoptosis. The transient and stable expression of core protein in Jurkat cells increased the sensitivity of cells to Fas-mediated apoptosis when compared to control cells expressing vector DNA alone. In addition, we demonstrated that the core protein binds to the cytoplasmic domain of Fas which may enhance the downstream signaling event of Fas-mediated apoptosis. The expression of core protein did not alter the cell surface expression of Fas, indicating that the increased sensitivity of core-expressing cells to Fas ligand was not due to upregulation of Fas. Furthermore, we observed the augmentation of caspase-3 activity in core-expressing cells. These results suggest that the core protein may promote the apoptosis of immune cells during HCV infection via the Fas signaling pathway, thus facilitating HCV persistence.

Activation-dependent degradation of protein kinase C eta

Prolonged activation of protein kinase Cs (PKCs) by long-term treatment of cells with phorbol ester tumor promoters down-regulates the expression of many PKCs. To investigate the molecular mechanisms involved in the down-regulation of PKC eta, we expressed the novel PKCs eta and θ and various mutant forms in baby hamster kidney cells. Upon overexpression, constitutively active PKC eta, but not wild type or kinase-dead PKC eta, underwent rapid degradation to generate several lower molecular weight polypeptides. When co-expressed with active kinases, kinase-dead PKC eta with a pseudosubstrate site mutation designed to give an active conformation was down-regulated while the wild type PKC eta was not. These results suggest requirements for kinase activity and an active conformation for down-regulation of PKC eta. Treatment with the proteasome inhibitors N-Ac-Leu-Leu-norleucinal and lactacystin led to accumulation of PKC eta proteolytic products and potentially ubiquitinated forms. While wild type PKC eta localizes mostly to the detergent-soluble fraction of the cell, a significant portion of full-length constitutively active PKC eta and of kinase-dead, active conformation PKC eta were found in the detergent-insoluble fraction. Several proteolytic fragments of constitutively active PKC eta also were found in the detergent insoluble fraction. These full-length and proteolytic fragments of PKC eta in the detergent-insoluble fraction accumulated further in the presence of proteasome inhibitors. These data suggest that active conformation PKC eta accumulates in the detergent-insoluble compartment, is degraded by proteolysis in the presence of kinase activity, and that the cleavage products undergo further degradation via ubiquitin-mediated degradation in the proteasome. Oncogene (2000) 19, 4263 - 4272

Clonal expansion of infiltrating T cells in the spinal cords of SJL/J mice infected with Theiler's virus

Intracerebral infection of susceptible mice with Theiler's murine encephalomyelitis virus results in immune-mediated inflammatory demyelination in the white matter and consequent clinical symptoms. This system has been utilized as an important virus model for human multiple sclerosis. Although the potential involvement of virus-specific Th cells has been studied extensively, very little is known about the nature of T cells infiltrating the CNS during viral infection and their role in the development of demyelinating disease. In this study, the clonal nature of T cells in the spinal cord during the disease course was analyzed using size spectratyping and sequencing of the TCR beta-chain CDR3 region. These studies clearly indicate that T cells are clonally expanded in the CNS after viral infection, although the overall TCR repertoire appears to be diverse. The clonal expansion appears to be Ag-driven in that it includes Th cells specific for known viral epitopes. Interestingly, such restricted accumulation of T cells was not detectable in the infiltrates of mice with proteolipid protein peptide-induced experimental autoimmune encephalomyelitis. The initial T cell repertoire (7-9 days postinfection) seems to be more diverse than that observed in the later stage (65 days) of virally induced demyelination, despite the more restricted utilization of Vbeta subfamilies. These results strongly suggest continuous stimulation and clonal expansion of virus-specific T cells in the CNS of Theiler's murine encephalomyelitis virus-infected mice during the entire course of demyelinating disease.

Therapeutic dilemmas in the management of thyroid cancer with laryngotracheal involvement

Invasion of the larynx and trachea by thyroid cancer is an uncommon but difficult problem. There is no consensus on indication for or extent of surgery, particularly when there is a requirement for airway reconstruction. From 1989 through 1996, we treated 22 patients with thyroid carcinoma with invasion of the larynx and trachea. Seventeen of these patients had recurrent disease. We applied radioactive iodine therapy after regional ablative surgery to resectable tumors with or without lung metastasis, larynx-preserving surgery to extraluminal or small intraluminal tumors restricted to the short segment of trachea, or total laryngectomy to recurrent tumors deeply invading the cartilage framework of the larynx. We performed arytenoid adduction or thyroplasty in one stage if the recurrent laryngeal nerve was paralyzed or resected intraoperatively. We could get relatively good survival and functional results by aggressive surgical treatment in 20 patients, but the disease was inoperable in 2 patients. It is stressed that head and neck surgeons who have to deal with cancer of the thyroid should not only be familiar with various techniques of airway reconstruction and voice rehabilitation but also must be aware of the biologic behavior of the thyroid carcinoma.

Membrane stretch increases the activity of Ca(2+)-activated K+ channels in rabbit coronary vascular smooth muscles

It has been proposed that Ca(2+)-activated K+ channels play an essential role in maintaining vascular tone during stretch of blood vessel. However, the underlying mechanism of stretch-induced change of Ca(2+)-activated K+ channel activities are still unknown. The present experiment was designed to investigate the effect of membrane stretch on these channels whose activity was measured from rabbit coronary smooth muscle cells using a patch clamp technique. Ca(2+)-activated K+ channel were identified by their Ca2+ and voltage dependencies and its large conductances as in other preparations. Perfusion of cells with a hypotonic solution, which mimics stretching the cell membrane by making a cell swelling, produced an increase in channel activity in cell-attached patch mode. The similar increase was observed when negative pressure was applied into the patch pipette for stretching the cell membrane within a patch area. In inside-out patch, stretch still increased channel activity even under the conditions which exclude the possible involvement of secondary messengers, or of transmembrane Ca2+ influx via stretch-activated cation channels. Pretreatment of arachidonic acid or albumin showed no effect on stretch-induced channel activation, excluding the possibility of fatty acids mediated channel activation during membrane stretch. These results indicate that the stretch may directly increase the activity of Ca(2+)-activated K+ channels in our experimental condition.

Hexakis(antipyrine-O)terbium(III) triperchlorate

In the title compound, hexakis(1,2-dihydro-1,5-dimethyl-2-phenyl-3H-pyrazol-3-one-O)terbium(III) triperchlorate, [Tb(C(11)H(12)N(2)O)(6)](ClO(4))(3), the Tb atom lies on a site of $\overline 3$ crystallographic symmetry and the unique Tb-O distance is 2.278 (2) A. One of the perchlorate anions has threefold crystallographic symmetry, while the other is disordered about a $\overline 3$ site.

Cloning and molecular characterization of the genes for carbon monoxide dehydrogenase and localization of molybdopterin, flavin adenine dinucleotide, and iron-sulfur centers in the enzyme of Hydrogenophaga pseudoflava

Carbon monoxide dehydrogenases (CO-DH) are the enzymes responsible for the oxidation of CO to carbon dioxide in carboxydobacteria and consist of three nonidentical subunits containing molybdopterin flavin adenine dinucleotide (FAD), and two different iron-sulfur clusters (O. Meyer, K. Frunzke, D. Gadkari, S. Jacobitz, I. Hugendieck, and M. Kraut, FEMS Microbiol. Rev. 87:253-260, 1990). The three structural genes of CO-DH in Hydrogenophaga pseudoflava were cloned and characterized. The genes were clustered on the chromosome in the transcriptional order cutM-cutS-cutL. The cloned cutM, cutS, and cutL genes had open reading frames of 864, 492, and 2,412 nucleotides, coding for proteins with calculated molecular weights of 30,694, 17,752, and 87,224, respectively. The overall identities in the nucleotide sequence of the genes and the amino acid sequence of the subunits with those of other carboxydobacteria were 64.5 to 74.3% and 62.8 to 72.3%, respectively. Primer extension analysis revealed that the transcriptional start site of the genes was the nucleotide G located 47 bp upstream of the cutM start codon. The deduced amino acid sequences of the three subunits of CO-DH implied the presence of molybdenum cofactor, FAD, and iron-sulfur centers in CutL, CutM, and CutS, respectively. Fluorometric analysis coupled with denaturing polyacrylamide gel electrophoresis of fractions from hydroxyapatite column chromatography in the presence of 8 M urea of active CO-DH and from gel filtration of spontaneously inactivated enzyme revealed that the large and medium subunits of CO-DH in H. pseudoflava bind molybdopterin and FAD cofactors, respectively. Iron-sulfur centers of the enzyme were identified to be present in the small subunit on the basis of the iron content in each subunit eluted from the denaturing polyacrylamide gels.

The involvement of K+ channels and the possible pathway of EDHF in the rabbit femoral artery

Experiments were designed to characterize the cellular mechanisms of action of endothelium-derived vasodilator substances in the rabbit femoral artery. Acetylcholine (ACh, 10(-8)-10(-5) M) induced a concentration-dependent relaxation of isolated endothelium-intact arterial rings precontracted with norepinephrine (NE, 10(-6) M). The ACh-induced response was abolished by the removal of endothelium. NG-nitro-L-arginine (L-NAME, 10(-4) M), an inhibitor of NO synthase, partially inhibited ACh-induced endothelium-dependent relaxation, whereas indomethacin (10(-5) M) showed no effect on ACh-induced relaxation. 25 mM KCl partially inhibited ACh-induced relaxation by shifting the concentration-response curve and abolished the response when combined with L-NAME and NE. In the presence of L-NAME, ACh-induced relaxation was unaffected by glibenclamide (10(-5) M) but significantly reduced by apamin (10(-6) M), and almost completely blocked by tetraethylammonium (TEA, 10(-3) M), iberiotoxin (10(-7) M) and 4-aminopyridine (4-AP, 5 x 10(-3) M). The cytochrome P450 inhibitors, 7-ethoxyresorufin (7-ER, 10(-5) M) and miconazole (10(-5) M) also significantly inhibited ACh-induced relaxation. Ouabain (10(-6) M), an inhibitor of Na+, K(+)-ATPase, or K(+)-free solution, also significantly inhibited ACh-induced relaxation. ACh-induced relaxation was not significantly inhibited by 18-alpha-glycyrrhetinic acid (18 alpha-GA, 10(-4) M). These results of this study indicate that ACh-induced endothelium-dependent relaxation of the rabbit femoral artery occurs via a mechanism that involves activation of Na+, K(+)-ATPase and/or activation of both the voltage-gated K+ channel (Kv) and the large-conductance, Ca(2+)-activated K+ channel (BKCa). The results further suggest that EDHF released by ACh may be a cytochrome P450 product.

(-)-Epiafzelechin: cyclooxygenase-1 inhibitor and anti-inflammatory agent from aerial parts of Celastrus orbiculatus

An inhibitor of cyclooxygenase (COX)-1 activity of prostaglandin H2 synthase was isolated from aerial parts of Celastrus orbiculatus Thunb. (Celastraceae), an oriental folk medicine for rheumatoid arthritis by activity-guided column chromatographic methods. The COX inhibitor was identified as (-)-epiafzelechin, a member of flavan-3-ols by the structural analysis with HR-EI-mass, 1H-NMR and 13C-NMR spectral data. The compound exhibited a dose-dependent inhibition on the COX activity with an IC50 value of 15 microM. (-)-Epiafzelechin exhibited about 3-fold weaker inhibitory potency on the enzyme activity than indomethacin as a positive control. (-)-Epiafzelechin exhibited significant anti-inflammatory activity on carrageenin-induced mouse paw edema when the compound (100 mg/kg) was orally administrated at 1 h before carrageenin treatment.

Inhibitory effects of resveratrol analogs on unopsonized zymosan-induced oxygen radical production

Resveratrol, a natural hydroxystilbene, has been reported to have anti-inflammatory and anticarcinogenic activities. Inhibitory effects of resveratrol and its analogs on reactive oxygen species (ROS) production in unopsonized zymosan-stimulated murine macrophage Raw264.7 cells, human monocytes, and neutrophils were analyzed to investigate if the anti-inflammatory and anticarcinogenic activities of resveratrol are related to the inhibition of ROS production. Resveratrol was a potent inhibitor of ROS production in both unopsonized zymosan-stimulated Raw264.7 cells and human monocytes and neutrophils. Resveratrol exhibited 50% inhibition values (IC50) of 17 microM in activated Raw264.7 cells, 18 microM in human monocytes, and 23 microM in human neutrophils. 3,5-Dihydroxy-4'-methoxystilbene or 3,4'-dimethoxy-5-hydroxystilbene exhibited IC50 values of 63 or 73 microM in Raw264.7 cells, 51 or >100 microM in human monocytes, and 10 or 37 microM in human neutrophils, respectively. Trimethylresveratrol, piceid, and 3,5-dihydroxy-4'-methoxystilbene-3-O-beta-D-glucoside were weak inhibitors of ROS production. Thus, resveratrol was identified as a potent inhibitor of ROS production, which might be one biochemical mechanism related to its anti-inflammatory and anticarcinogenic activities. The number and position of hydroxy substituents in resveratrol analogs seem to play an important role in the inhibitory potency of ROS production.

Inhibitory effects of streptozotocin, tumor necrosis factor-alpha, and interleukin-1beta on glucokinase activity in pancreatic islets and gene expression of GLUT2 and glucokinase

Treatment of streptozotocin (ST), tumor necrosis factor-alpha (TNF-alpha), and interleukin-1beta (IL-1beta) resulted in destroying insulin-secreting beta-cells of pancreatic islets and impairment of islet glucose oxidation and glucose-induced insulin secretion. IL-1beta and TNF-alpha inhibited insulin release and glucose utilization and oxidation. It was shown that the inhibitory effects of ST, IL-1beta, and TNF-alpha were due to impaired glucokinase activity. Glucokinase activity was severely impaired by ST, IL-1beta, and TNF-alpha treatments, as confirmed by assaying enzymes and nucleotides associated with glycolysis and glucose oxidation. On the other hand, nitric oxide was a factor of the deleterious effects of IL-1beta, TNF-alpha, and ST on pancreatic islets. Incubation of mouse pancreatic islets with ST at various concentrations of impairing insulin secretion resulted in generation of nitrite, stimulation of islet guanylyl cyclase and accumulation of cGMP, and inhibition of pancreatic islet mitochondrial aconitase activity to degree similar to those raised by IL-1beta and TNF-alpha. When the effects of IL-1beta and TNF-alpha on the gene expression of pancreatic GLUT2 and glucokinase were examined, the level of GLUT2 and glucokinase mRNA in pancreatic islets was significantly decreased. This suggested that IL-1beta and TNF-alpha downregulate gene expression of GLUT2 and glucokinase in pancreatic beta-cells.

Differential downstream functions of protein kinase Ceta and -theta in EL4 mouse thymoma cells

Sensitive EL4 mouse thymoma cells (s-EL4) respond to phorbol esters with growth inhibition, adherence to substrate, and production of cytokines including interleukin 2. Since these cells express several of the phorbol ester-sensitive protein kinase C (PKC) isozymes, the function of each isozyme remains unclear. Previous studies demonstrated that s-EL4 cells expressed substantially more PKCeta and PKCtheta than did EL4 cells resistant to phorbol esters (r-EL4). To examine potential roles for PKCeta and PKCtheta in EL4 cells, wild type and constitutively active versions of the isozymes were transiently expressed using a Sindbis virus system. Expression of constitutively active PKCeta, but not PKCtheta, in s- and r-EL4 cells altered cell morphology and cytoskeletal structure in a manner similar to that of phorbol ester treatment, suggesting a role for PKCeta in cytoskeletal organization. Prolonged treatment of s-EL4 cells with phorbol esters results in inhibition of cell cycling along with a decreased expression of most of the PKC isozymes, including PKCtheta. Introduction of virally expressed PKCtheta, but not PKCeta, overcame the inhibitory effects of the prolonged phorbol ester treatment on cell cycle progression, suggesting a possible involvement of PKCtheta in cell cycle regulation. These results support differential functions for PKCeta and PKCtheta in T cell activation.

Effects of hypoxia on pulmonary vascular contractility

Although hypoxic pulmonary vasoconstriction (HPV) has been recognized by many researchers, the precise mechanism remains unknown. As isolated pulmonary arteries will constrict in vitro in the response to hypoxia, the oxygen sensor/transduction mechanism must reside in the pulmonary arterial smooth muscle or in the endothelium, or in both. Unfortunately, much of the current evidence is conflicting, especially as to the dependency of HPV on the endothelium and the role of a K+ channel. Therefore, this experiment was attempted to clarify the dependency of HPV on the endothelium and the role of a K+ channel on HPV in rat pulmonary artery. The effects of hypoxia were investigated in isolated main pulmonary arteries precontracted with norepinephrine. Vascular rings were suspended for isometric tension recording in an organ chamber filled with a Krebs-Henseleit solution. Hypoxia was induced by gassing the chamber with 95% N2 + 5% CO2 and this was maintained for 20 min. Hypoxia elicited a vasoconstriction in arteries with endothelium. Mechanical disruption of the endothelium abolished HPV. There was no difference between the amplitude of the HPV induced by two consecutive hypoxic challenges and the effect of normoxic and hyperoxic control Krebs-Henseleit solution on a subsequent response to hypoxia. Inhibition of NO synthesis by treatment with N(omega)-nitro-L-arginine reduced HPV, but inhibition of a cyclooxygenase pathway by treatment with indomethacin had no effect on HPV. Blockades of a tetraetylammonium chloride-sensitive K+ channel abolished HPV. Verapamil, a Ca2+ entry blocker reduced HPV. In conclusion, these results suggest that HPV was dependent on the endothelium and that HPV can be considered to be induced by inhibition of the mechanisms of NO-dependent vasodilation such as the opening of a K+ channels.

Mechanisms of relaxation of coronary artery by hypoxia

This study was designed to clarify the dependency of hypoxic coronary vasodilation (HCD) on the endothelium and the role of the K+ channels on HCD in the rabbit coronary artery. HCD was investigated in an isolated left circumflex coronary artery precontracted with prostaglandin F2 alpha. Vascular rings were suspended for isometric tension recording in an organ chamber filled with Krebs-Henseleit (KH) solution. Hypoxia was induced by gassing the chamber with 95% N2 + 5% CO2 and was maintained for 15 approximately 25 min. Hypoxia elicited a vasodilation in the precontracted coronary artery with and without endothelium. There was no difference between the amplitude of the HCD induced by two consecutive hypoxic challenges and the effects of 20% O2 + 5% CO2 + 75% N2 and 95% O2 + 5% CO2 control K-H solution of subsequent responses to hypoxia. Inhibition of the cyclooxygenase pathway by treatment with indomethacin had no effect on HCD. Blockades of the tetraethylammonium chloride-sensitive K+ channel abolished HCD. Apamin, a blocker of the small conductance Ca(2+)-activated K+ (KCa) channel, and iberiotoxin, a blocker of the large conductance KCa channel had no effect on HCD, respectively. Glibenclamide, a blocker of the ATP-sensitive K+ (K+ATP) channel, reduced HCD. Cromakalim, an opener of the K+ATP channel, relaxed the coronary artery precontracted with prostaglandin F2 alpha. The degree of relaxation by cromakalim was similar to that by hypoxia while glibenclamide reduced both hypoxia- and cromakalim-induced vasodilatations. In conclusion, these results suggest that HCD is independent on endothelium and HCD is considered to be induced by activation of K+ATP channel.

Structure of catechol 2,3-dioxygenase gene from Alcaligenes eutrophus 335

Catechol 2,3-dioxygenase (C23O), one of extradiol-type dioxygenases cleaving aromatic C-C bond at meta position of dihydroxylated aromatic substrates, catalyzes the conversion of catechol to 2-hydroxymuconic semialdehyde. As our ongoing study to characterize biochemical and genetic properties of the extradiol-type dioxygenases at molecular level, a C23O gene encoded in chromosomal DNA of Alcaligenes eutrophus 335, a strain degrading phenol and p-cresol, was cloned. The C23O gene was localized in an 1.4-kb PstI fragment from A. eutrophus 335, and was expressed in E. coli HB101. The C23O exhibited the highest aromatic ring-fission activity to catechol as a substrate, and its relative activity to other dihydroxylated aromatic substrates was in order of catechol >> 4-methylcatechol > 3-methylcatechol, protocatechuate, 4-chlorocatechol > 3,4-dihydroxy-phenylacetate > 2,3-dihydroxybiphenyl. Nucleotide sequence of the 1.4-kb fragment has revealed that an open reading frame (ORF) corresponding to the C23O gene was composed of 930 base pairs. A putative ribosome-binding sequence of AGGAG was found at about 10 nucleotides upstream the ORF which can encode a polypeptide of molecular weight 34 kDa consisting of 309 amino acid residues. The deduced amino acid sequence of C23O from A. eutrophus 335 exhibited the highest 59% identity with those of corresponding enzymes from Pseudomonas sp. CF600 (p VI150), P. putida HS1 (pDK1), and P. putida PpG7 (NAH7). An alignment of amino acid sequences of extradiol-type dioxygenases including C23O from A. eutrophus 335 has revealed that catalytically and structurally important amino acid residues of the enzymes were conserved during evolution.

Changes in arterial blood PO2, PCO2, and pH during deep hypothermic circulatory arrest in adults

Safe limits of time and temperature during sleep hypothermic circulatory arrest (DHCA) still remain controversial. Furthermore, continuous changes of PaO2, PaCO2, and pH have never been measured during DHCA in humans. Continuous intraarterial blood gas (CIABG) monitoring is a new technology allowing us to study chronological changes occurring due to metabolism during DHCA. When the patients' temperature reached 18 approximately 20 degrees C following establishment of cardiopulmonary bypass (CPB), circulatory arrest was initiated. After a 20-minute period of DHCA, reperfusion commenced with 18 degree C blood. We continuously monitored PaO2, PaCO2, and pH immediately before, during and following DHCA. Data was analyzed by Student's t-test. PaO2, PaCO2, and pH of pre- and 5 minutes post DHCA were not significantly different from each other. However, during DHCA, the PaO2 was significantly decreased from 229 +/- 34 to 30 +/- 23 mmHg at 20-minute intervals. But the PaCO2 increased significantly after 20 minutes of circulatory arrest from 34 +/- 5 to 42 +/- 6 mmHg. However, the pH did not change significantly over the 20-minute period. The PaO2 level after 20 minutes is much lower than before DHCA, it would be well tolerated in normothermic adults. The PO2 level in the brain may be even lower given its high metabolic rate. So measuring arterial PO2 continuously during DHCA may provide a surrogate method for determining maximum safe time under DHCA for adults.

Changes in intracellular Ca2+ concentration of rabbit coronary artery smooth muscle cell during ischemic cardioplegic period

To elucidate the possibility whether an elevation of intracellular Ca2+ concentration ([Ca2+]i) in rabbit coronary artery myocytes during ischemic cardioplegic period may serve as one of the mechanisms of the "no-reflow' phenomenon or not, the changes in [Ca2+]i were measured under ischemic cardioplegia conditions using a fluorescent Ca2+ indicator, fura 2/AM. When single cells were perfused with cardioplegic or ischemic cardioplegic solutions, [Ca2+]i was significantly increased and the degree of [Ca2+]i elevation was further augmented by the ischemic cardioplegic solution. Pretreatment of a sarcoplasmic reticulum emptying agent, 20 mM caffeine, had no effect on ischemic cardioplegia-induced [Ca2+]i changes, but application of a Ca2+ channel blocker, 5 x 10 (-1)M nifedipine, or an antagonist of Na+/Ca2+ exchange, 5 mM Ni2+, significantly inhibited the [Ca2+]i elevation, respectively. The magnitude of ischemic cardioplegia-induced [Ca2+]i elevation was dependent on the Ca2+ concentration of perfusate in the range of 0 and 25 mM. When Ni2+ was added to the reperfusion solution, recovery of ischemic cardioplegia-induced [Ca2+]i elevation was very rapid compared with the controls. It is concluded that ischemic cardioplegia-induced [Ca2+]i elevation may serve as one of the mechanisms of the "no-reflow' phenomenon in rabbit coronary artery smooth muscle cells. We propose that Na+/Ca2+ exchange may serve as a key function in ischemic cardioplegia-induced [Ca2+]i elevation.

Sprouting of sympathetic nerve fibers into the dorsal root ganglion following peripheral nerve injury depends on the injury site

Peripheral nerve injury often induces sympathetic nerve fiber sprouting in the dorsal root ganglion (DRG) and injured nerve. Presently, the underlying mechanism and functional significance of the sprouting are unknown. This study was performed to see whether the degree of the sprouting in the DRG was a function of the distance between the DRG and injury site. To this aim, we compared two groups of rats with respect to the sympathetic nerve fibers sprouting in the S1-3 DRG; one group was subjected to unilateral inferior and superior caudal trunk transections at the level between the S3 and S4 spinal nerves (S34 group) and the other group at the levels between the S1 and S2, between S2 and S3 and between S3 and S4 spinal nerves (S123 group). The transections in both groups equally eliminated the inputs from the tail to the S1-3 DRG, but the distance from the S1/S2 DRG to the injury site was different between the two groups. Immunohistochemical staining with tyrosine hydroxylase (TH) antibody of the S1-3 DRG removed from rats a week after the injury revealed that the degree of penetration of TH-positive fibers into the S1 and S2 DRG was much more extensive in the S123 group than in the S34 group, whereas that into the S3 DRG was not significantly different between the two groups. These results suggest that the extent of the sympathetic nerve fiber sprouting in the DRG following peripheral nerve injury is inversely related to the distance between the DRG and injury site.

Characteristics of Ca2+ release mechanisms from an intracellular Ca2+ store in rabbit coronary artery

To elucidate the Ca2+ release mechanisms in the rabbit coronary artery, arterial preparations were permeabilized with beta-escin and changes in tension were measured under varying experimental conditions. Additionally, we investigated properties and distribution of two kinds of Ca2+ release mechanisms, Ca2+-induced Ca2+ release (CICR) and IP3-induced Ca2+ release (IICR). The results obtained were summarized as follows; 1. When a rabbit coronary artery was incubated in a relaxing solution containing 30 microM beta-escin for 40 min. sensitivity to externally added Ca2+ was much higher in beta-escin permeabilized muscle than in intact preparations. The contractile effect of IP3 in beta-escin permeabilized muscle was also demonstrated; 2. Caffeine and IP3 contracted coronary arteries were permeabilized with beta-escin, but the amplitude of contraction was much larger in the presence of caffeine than of IP3. 3. Intracellular heparin completely inhibited the contractions induced by IP3, but not those by caffeine. On the other hand, procaine inhibited the responses to caffeine, but not those to IP3. Ryanodine inhibited both the caffeine- and IP3-induced contractions. 4. The amplitude of contractile responses was much larger to the maximal stimulation of CICR by applying caffeine than to the maximal stimulation of IICR by applying IP3. After the maximal CICR stimulation by caffeine, the activation of IICR by IP3 without the reloading of Ca2+ could no longer evoke contraction. On the other hand, after the maximal IICR activation, the activation of CICR could still evoke contraction although the amplitude of the contraction was smaller when compared with the case without the initial IICR stimulation. 5. Acetylcholine contracted coronary artery smooth muscles were permeabilized with beta-escin. However, in the absence of added guanosine triphosphate (GTP), the responses were very small. Acetylcholine-induced contraction was inhibited by heparin, but not by procaine. From the above results, it may be concluded that there are two kinds of mechanisms of Ca2+ release, CICR and IICR, in the rabbit coronary artery smooth muscle cell. Also, whereas the CICR mechanism distributes on the membrane of the whole smooth muscle Ca2+ store, the IICR mechanism distributes only on a part of it.

Hypoxic contraction of isolated rat pulmonary artery

The effects of hypoxia in precontracted rat pulmonary artery rings with and without endothelium was studied. Hypoxia (30 mmHg) produced a contraction (hypoxic pulmonary vasoconstriction, HPV). Removal of endothelium abolished the HPV. The HPV was reproducible. The amplitude of HPV was similar to arteries equilibrated with 100% O2 and room air. L-NNA markedly inhibited the HPV whereas indomethacin was ineffective. HPV was inhibited by caffeine, but not inhibited by nifedipine. It would be concluded that HPV in isolated rat pulmonary arteries is dependent on the endothelium and the mechanisms involved may be inhibition of basal NO production.

The effect of lovastatin on proliferation of cultured rat mesangial and aortic smooth muscle cells

In order to investigate the anti-proliferative effect of 3-hydroxy-3-methylglutaryl coenzyme. A reductase inhibitor, we evaluated the effects of lovastatin on DNA replication and the proliferation of rat mesangial and aortic smooth muscle cells, both of which were mesenchymal origin cells. Proliferations were determined by measuring [3H]thymidine uptake, and counting the number of cells. Growth-arrested mesangial and aortic smooth muscle cells were exposed to platelet-derived growth factor (PDGF), endothelin (ET) and angiotensin II (Ang II) to stimulate mitogenesis. All agents exhibited dose-dependent stimulation of [3H] thymidine uptake. PDGF was more potent than the others. Ang II increased [3H] thymidine uptake without demonstrable mitogenic activity. Lovastatin inhibited PDGF (10 ng/ml in mesangial cell, 25 ng/ml in smooth muscle cell)-, ET (10(-7)M)- and Ang II (10(-7)M)-induced [3H] thymidine uptake significantly in a dose-dependent manner in both cells. The increase of cell number in response to PDGF and ET treatment were also inhibited at 10 microM of lovastatin. The inhibitory effect of lovastatin was largely overcome in the presence of exogenous mevalonate at 200 microM, with 75.5% restoration from lovastatin-induced inhibition on PDGF-induced [3H] thymidine uptake in mesangial cells (77.8% in aortic smooth muscle cells). However, the addition of cholesterol did not prevent inhibition by lovastatin. In conclusion, lovastatin had an inhibitory effect on mesangial and aortic smooth muscle cell proliferation, and mevalonate was essential for DNA replication in both types of cells. Lovastatin may reduce glomerular and atherosclerotic injury through an anti-proliferative effect on mesangial and vascular smooth muscle cells, in addition to lowering circulating lipids.