Adventitia as a source of inducible nitric oxide synthase in the rat aorta

In the current study we used in vitro and in vivo models to determine the sites of nitric oxide production in rat aortic tissue following cytokine stimulation. In vitro studies in which intact rat aortic rings were incubated with endotoxin (1 microg/mL) or interferon-gamma (600 U/mL) indicated that the expression of inducible nitric oxide synthase (iNOS) activity was increased as measured by Northern blot analysis or determination of nitrite production. In situ hybridization showed iNOS mRNA in the endothelium and adventitia of the incubated aortic rings but not in the media. Immunohistochemical staining showed a similar localization for iNOS protein in the incubated rings. Additional studies were performed in which bacterial endotoxin (4 mg/kg) was administered to rats, and iNOS expression was assayed using in situ hybridization and immunohistochemistry. Clear increases in iNOS mRNA and protein were found in aortic tissue. Endothelial and adventitial cells were the major source of iNOS, with relatively low amounts of iNOS mRNA present in medial smooth muscle, consistent with in vitro findings. These studies indicate that the aortic adventitia is a potential source of NO, and suggest that the adventitial fibroblast may have an important paracrine role in regulating arterial structure and function.

[HLA-DQA1 genes involved in the genetic susceptibility to duodenal ulcer in Wuhan Hans]

OBJECTIVE

To study the genetic susceptibility of HLA-DQA1 alleles to duodenal ulcer in Chinese Hans from Wuhan and its nearby regions.

METHODS

Seventy patients with duodenal ulcer and fifty healthy controls were examined for HLA-DQA1 genotypes. HLA-DQA1 typing was carried out by digesting the locus specific polymerase chain reaction amplified products with alleles specific restriction enzymes (PCR-RFLP), Apal I, Basj I, Hph I, Fok I, Mbo II and Mnl I.

RESULTS

The allele frequency of DQA1 0301 in patients with duodenal ulcer (64.3%) was significantly higher than that in healthy controls (36%). In contrast, the allele frequency of DQA1 0102 in patients with duodenal ulcer (8.6%) was significantly lower than that in healthy controls (26%).

CONCLUSION

These findings suggest that DQA1 0301 is a susceptible gene for duodenal ulcer in Wuhan Hans while DQA1 0102 is its resistant gene, and there are immunogenetic differences in HLA-DQA1 locus between duodenal ulcer patients and healthy controls.

Identification of genomic regions controlling experimental autoimmune uveoretinitis in rats

The present study attempts to identify specific genetic loci contributing to experimental autoimmune uveoretinitis (EAU) susceptibility in F2 progeny of resistant Fischer (F344/N) and susceptible Lewis (LEW/N) inbred rats. F2 progeny of F344/N x LEW/N inbred rats were immunized with the R16 peptide of interphotoreceptor retinoid-binding protein (IRBP). A genome-wide scan was conducted using 125 simple sequence length polymorphism markers in selected F2 animals that developed severe eye disease or remained unaffected to identify phenotype:genotype co-segregation. The F2 population (n = 1287) demonstrated a wide range of histologically assessed EAU scores (assessed on a scale of 0-4). The disease incidence and severity were not consistent with a simple Mendelian inheritance model. Of the F2 hybrid rats, 60% developed EAU, implying the existence of a potent susceptibility locus with incomplete penetrance associated with the LEW genome or a more complex polygenic model of inheritance. Two genomic regions, on chromosomes 4 and 12, showed strong genetic linkage to the EAU phenotype (P < 0.0016), suggesting the presence of susceptibility loci in these chromosomal regions. In conclusion, we have identified two genomic candidate intervals from D4Arb8 to D4Mit17 on chromosome 4 and from the chromosome end to D12Arb8 on chromosome 12, that appear to influence EAU susceptibility in LEW/F344 rats. Further analysis of these genomic regions may lead to identification of the susceptibility genes and to characterization of their function.

[Purification and identification of pili of Vibrio cholera O139]

To provide the base of manufacturing V. cholera O139 subunit vaccine, purification and identification methods of V. cholera O139 Toxin-coregulated pili (TCP) were studied. The results showed the optimal expressing condition of TCP was in AKI or CFA medium, at 30 C for 24-36 h with stationary cultivation. The molecular weight of the TCP subunit protein measured by sodium dodecyl sulfate-poly acrylamide gel electrophoresis was about 20.5 kd. By using mouse anti-TCP monoclone antibody and sheep anti-mouse IgG-HRP antibody, the TCP was confirmed by dot blot immunoassay. Rabbit immune serum of TCP purified from O139 strain agglutinated both O139 biotype and El Tor biotype Vibrio cholera strains. These indicate that TCP may be an effective and protective antigen to conduct the preparation of V. cholera vaccine.

A short conserved motif is required for repressor domain function in the myeloid-specific transcription factor CCAAT/enhancer-binding protein epsilon

CCAAT/enhancer-binding protein epsilon (C/EBPepsilon) is expressed almost exclusively in the myeloid lineage of the hematopoietic system and functions during terminal differentiation of neutrophils and macrophages, and in the regulation of cytokine gene expression in macrophages and T cells. We have undertaken a series of structure/function studies on the murine C/EBPepsilon polypeptide to investigate the mechanism by which C/EBPepsilon activates transcription. Studies with deletion mutants and fusion proteins consisting of C/EBPepsilon sequences joined to the Gal4 DNA-binding protein identified two transcriptional activation domains in C/EBPepsilon. Removal of sequences between the two activation domains or sequences between the second activation domain and the C-terminal DNA binding domain significantly increased the activity of C/EBPepsilon, suggesting the presence of two separate regulatory domains (designated RD-1epsilon and RD-2epsilon). RD-1epsilon behaved as a classic active repressor domain being capable of inhibiting adjacent activation domains irrespective of their origin and when linked to a heterologous DNA binding domain. Mutagenesis studies revealed a short motif in RD-1epsilon that appears to be a target site for protein-protein interactions and is conserved in repressor domains from C/EBPbeta, Sp3, c-Fos, and FosB. The juxtaposition of activation and repressor domains may permit C/EBPepsilon to function as a transcriptional activator or repressor at different stages of myeloid differentiation or as an inducible transcriptional activator of cytokine genes.

The effects of beta-bungarotoxin on the morphogenesis of taste papillae and taste buds in the mouse

Although it has been long accepted that innervation by a taste nerve is essential for maintenance of taste buds, it is not clear what role, if any, innervation plays in the morphogenesis of taste papillae and taste bud development. The following study was undertaken to determine what effects lack of sensory innervation have on the development of taste papillae and the formation of taste buds in the mouse. Timed-pregnant female mice (n = 3) at gestational day 12 (gd12) were anesthetized and a 1 microl solution (1 microg/microl) of beta-bungarotoxin (beta-BTX), a neurotoxin that disrupts sensory and motor neuron development, was injected into the amniotic cavity of two embryos per dam. Two shams were injected with PBS. Fetuses were harvested at gd18, 1 day before birth, and four beta-BTX-injected embryos, two shams and two controls were fixed in buffered paraformaldehyde. Serial sections were examined for the presence and morphology of taste papillae and taste buds. No nerve profiles were observed in beta-BTX-injected tongues. Although circumvallate papillae were present on beta-BTX tongues, only five fungiform papillae could be identified. Taste buds were present on a large percentage of fungiform papillae profiles (24%) and on circumvallate papillae in sham and control fetuses; in contrast, no taste buds were associated with taste papillae in beta-BTX fetuses. These results implicate a significant role for innervation in taste papillae and taste bud morphogenesis.

Caspase-3-like proteases and 6-hydroxydopamine induced neuronal cell death

Neurotoxicity induced by 6-hydroxydopamine (6-OHDA) is believed to be due, in part, to the production of reactive oxygen species (ROS) and/or an inhibition of mitochondrial function. However, little is known about the ensuing intracellular events which ultimately result in cell death. Here we show that exposure to relatively low concentrations of 6-OHDA induces apoptosis of cerebellar granule neurons (CGN). 6-OHDA-induced apoptosis of CGN is associated with activation of a caspase-3-like protease. Western blots of cytosolic extracts from 6-OHDA-treated CGN reveal a translocation of cytochrome c from mitochondria to the cytosol, which precedes activation of the protease detected by Ac-DEVD-pNA. DNA laddering can be blocked by caspase inhibitors zVAD-FMK and Ac-DEVD-CHO, however cell death can only be attenuated for a short time period in the presence of these inhibitors. Our data suggest that 6-OHDA-induced apoptosis of CGN involves activation of a caspase-3-like protease. In contrast to the neurotoxicity induced by MPP+, however, the peptide inhibitors zVAD-FMK and Ac-DEVD-CHO can only attenuate early neuronal death induced by 6-OHDA. At later time points, neuronal death lacking DNA laddering occurs even in the presence of the peptide inhibitor zVAD-FMK or Ac-DEVD-CHO.

Spatial Distribution of Green Mold Foci in 30 Commercial Mushroom Crops

Statistical analyses were performed on spatial distributions of mushroom green mold foci caused by Trichoderma spp. in 30 standard Pennsylvania doubles (743 m² production surface) selected at random from over 900 total crops mapped. Mapped production houses were divided into four tiers of six beds each with 16 sections per bed (total = 384 sections per double). Each section contained approximately 2 m². Green mold foci were mapped according to presence or absence in each section as they became visible during the course of the mushroom production. There was a trend toward higher disease incidence at the ends of the doubles, although this was not consistent from level to level. Spatial analysis revealed that green mold foci were more likely to occur in neighboring sections along the beds rather than above, below, or across from each other. Cultural practices that were associated with movement along the beds, i.e., nutrient supplementation, spawning, bed tamping, surface covering, etc., were considered the most likely factors influencing the incidence of green mold in spawned compost. Airborne contamination was considered a less likely source of inocula contributing to epidemic development. Sanitation practices that reduce spore loads along the beds are expected to provide the greatest degree of green mold control.

Alpha1-adrenergic plus angiotensin receptor blockade reduces atherosclerosis in apolipoprotein E-deficient mice

-We have used the apolipoprotein E (apoE)-deficient mouse model to determine whether both the angiotensin II type 1 (AT1) and the alpha1-adrenergic receptors influence arteriosclerotic changes in this hyperlipidemic animal model. Mice were treated with antihypertensive drugs beginning at 9 weeks of age, and aortic atherosclerosis was measured after 12 weeks of treatment. Systolic blood pressure in the untreated apoE-deficient mouse averaged 104 mm Hg throughout the treatment period. Prazosin at a dose of 7.5 mg. kg-1. d-1 was ineffective in attenuating atherosclerosis and did not significantly reduce blood pressure. Losartan, at dosages of either 20 or 30 mg. kg-1. d-1, also did not influence atherosclerosis and had only a slight blood pressure-lowering effect. However, combined treatment with both prazosin and losartan markedly reduced atherosclerotic lesion development from an average lesion size per section of 2.6 to 1.5x10(5) microm2 (P<0.001) and significantly reduced blood pressure to 85+/-5 mm Hg. Treatment with NG-nitro-L-arginine methyl ester (40 mg. kg-1. d-1) produced significant elevations of blood pressure (127+/-3.8 mm Hg) but had no effect on the development of atherosclerosis. None of the treatments used affected plasma cholesterol throughout the 12-week period. These studies suggest that the vascular changes associated with atherosclerosis are influenced by a combination of AT1 and alpha1-adrenergic receptor activation.

[Significance of resistance index and pulsatility index in differential diagnosis of breast neoplasm]

OBJECTIVE

To investigate the significance of the resistance index (RI) and pulsatility index (PI) in differential diagnosis between the benign and malignant breast neoplasms.

METHODS

Forty-seven cases of malignant breast tumors, sixty-nine cases of fibroadenomas, seven cases of inflammatory masses and twenty-two cases of mammiplasia were demonstrated on color Doppler flow imaging (CDFI). The measurements of RI and PI of the four groups were recorded respectively and the comparison between benign and malignant neoplasms was made by applying Doppler quantitative analysis.

RESULTS

The color flow was detected in 59.4% of benign breast neoplasms and in 89% of malignant ones respectively (chi 2-test, P < 0.001). There were significant difference between benign and malignant neoplasms on the RI and PI. The malignant neoplasms were characteristic of higher RI (> or = 0.70) and PI (> or = 1.30), which were of satisfactory value for differential diagnosis, amounting to 95.5% of accuracy.

CONCLUSIONS

Combination of both color Doppler analysis and 2D-US might remarkably increase the sensitivity and specificity of differential diagnosis of breast neoplasms. Our results confirmed the significance of color Doppler flow imaging and Doppler quantitative analysis on the differential diagnosis of breast neoplasms.

Peptide inhibitors of caspase-3-like proteases attenuate 1-methyl-4-phenylpyridinum-induced toxicity of cultured fetal rat mesencephalic dopamine neurons

Multiple aspartate-specific cysteine proteases have been identified and specific members of this family have been implicated in the apoptotic death of many mammalian cell types. Caspase-3-like proteases seem to play a pivotal role in neuronal apoptosis since mice with germline inactivation of the caspase-3 gene manifest profound alterations in neurogenesis. Moreover, inhibitors of caspase-3-related proteases have been shown to inhibit neuronal apoptosis. Here we extend recent work from our laboratory on the mechanisms mediating the neurotoxic actions of 1-methyl-4-phenylpyridinium using ventral mesencephalon cultures containing dopamine neurons. We demonstrate that low concentrations of 1-methyl-4-phenylpyridinium induce apoptosis in dopamine neurons by morphological and biochemical criteria. Moreover, pretreatment of ventral mesencephalon cultures with the tetrapeptide inhibitors of the caspase-3-like proteases zVAD-FMK or Ac-DEVD-CHO specifically inhibit death of dopamine neurons induced by low concentrations of 1-methyl-4-phenylpyridinium, whereas the caspase-1-like inhibitor Ac-YVAD-CHO was without effect. Our data indicate that exposure of cultured ventral mesencephalon dopamine neurons to low concentrations of 1-methyl-4-phenylpyridinium results in apoptotic death and that caspase-3-like proteases may mediate the neurotoxic apoptotic actions of 1-methyl-4-phenylpyridinium.

Identification of a novel cortactin SH3 domain-binding protein and its localization to growth cones of cultured neurons

Cortactin is an actin-binding protein that contains several potential signaling motifs including a Src homology 3 (SH3) domain at the distal C terminus. Translocation of cortactin to specific cortical actin structures and hyperphosphorylation of cortactin on tyrosine have been associated with the cortical cytoskeleton reorganization induced by a variety of cellular stimuli. The function of cortactin in these processes is largely unknown in part due to the lack of information about cellular binding partners for cortactin. Here we report the identification of a novel cortactin-binding protein of approximately 180 kDa by yeast two-hybrid interaction screening. The interaction of cortactin with this 180-kDa protein was confirmed by both in vitro and in vivo methods, and the SH3 domain of cortactin was found to direct this interaction. Since this protein represents the first reported natural ligand for the cortactin SH3 domain, we designated it CortBP1 for cortactin-binding protein 1. CortBP1 contains two recognizable sequence motifs within its C-terminal region, including a consensus sequence for cortactin SH3 domain-binding peptides and a sterile alpha motif. Northern and Western blot analysis indicated that CortBP1 is expressed predominately in brain tissue. Immunofluorescence studies revealed colocalization of CortBP1 with cortactin and cortical actin filaments in lamellipodia and membrane ruffles in fibroblasts expressing CortBP1. Colocalization of endogenous CortBP1 and cortactin was also observed in growth cones of developing hippocampal neurons, implicating CortBP1 and cortactin in cytoskeleton reorganization during neurite outgrowth.

Velocity difference measurement with a fiber-optic coupler

Two single-mode fibers collect light with the same scattered wave vector from two spatially separated regions in a sample. These regions are illuminated by a single coherent laser beam, so that the collected signals interfere when combined by means of a fiber-optic coupler, before they are directed to a photomultiplier tube. The fibers and the coupler are polarization preserving to guarantee a high signal-to-noise ratio. The measured intensity fluctuations are used to determine the velocity difference omega v(L) for spatial separations L in the sample. Specifically, an intensity autocorrelation function is calculated theoretically for rigid body rotation and is tested experimentally. Experimental results span two orders of magnitude in L and agree with theoretical predictions with an error of less than 5%. This new technique will be very useful in the study of turbulent flow and particle settling dynamics.

[The correlation between abusing alcohol and antioxidants, antioxidases]

OBJECTIVE

To study the correlation between abusing alcohol and antioxidants, antioxidases and oxygen free radical reaction.

METHODS

We measured spectrophotometrically the plasma vitamin C(P-VC), plasma vitamin E(P-VE), plasma beta-carotene (P-beta-CAR) contents and erythrocyte superoxide dismutase (E-SOD), erythrocyte catalase (E-CAT), erythrocyte glutathione peroxidase (E-GSH-Px) activities in 194 male (40 years old) alcohol abusers and 50 male (40 years old) nondrinkers.

RESULTS

The average P-VC, P-VE, P-beta-CAR contents and E-SOD, E-CAT, E-GSH-Px activities of the alcohol abuser group were lower than those of the nondrinker group. The P-VC, P-VE, P-beta-CAR contents and E-SOD, E-CAT, E-GSH-Px activities of the alcohol abusers decreased as the time and quantity of abusing alcohol increased.

CONCLUSION

The oxygen free radical reaction in the alcohol abusers was pathologically exacerbated, and the balance between oxidation and antioxidation was serious imbalanced.

Translocation of cortactin to the cell periphery is mediated by the small GTPase Rac1

Small GTPases of the Rho family regulate signaling pathways that control actin cytoskeletal structures. In Swiss 3T3 cells, RhoA activation leads to stress fiber and focal adhesion formation, Rac1 to lamellipoda and membrane ruffles, and Cdc42 to microspikes and filopodia. Several downstream molecules mediating these effects have been recently identified. In this report we provide evidence that the intracellular localization of the actin binding protein cortactin, a Src kinase substrate, is regulated by the activation of Rac1. Cortactin redistributes from the cytoplasm into membrane ruffles as a result of growth factor-induced Rac1 activation, and this translocation is blocked by expression of dominant negative Rac1N17. Expression of constitutively active Rac1L61 evoked the translocation of cortactin from cytoplasmic pools into peripheral membrane ruffles. Expression of mutant forms of the serine/threonine kinase PAK1, a downstream effector of Rac1 and Cdc42 recently demonstrated to trigger cortical actin polymerization and membrane ruffling, also led to the translocation of cortactin to the cell cortex, although this was effectively blocked by coexpression of Rac1N17. Collectively these data provide evidence for cortactin as a putative target of Rac1-induced signal transduction events involved in membrane ruffling and lamellipodia formation.

In vitro metabolism of 10-(3-chlorophenyl)-6,8,9,10-tetrahydrobenzo[b][1,8]naphthyridin-5(7H)- one, a topical antipsoriatic agent. Use of precision-cut rat, dog, monkey and human liver slices, and chemical synthesis of metabolites

The metabolism of SCH 40120, which is the clinically effective antipsoriatic drug 10-(3-chlorophenyl)-6,8,9,10-tetrahydrobenzol[b][1,8]naphthyrid in-5(7H)-one, was determined in vitro. Rat, dog, cynomolgus monkey, and human liver slices hydroxylated the aliphatic, cyclohexenyl ring of the drug and conjugated the resulting carbinol. The identified metabolites comprised the corresponding 6-, 7-, and 9-carbinols, the glucuronide of the 6-carbinol, and the 6-ketone derived from the parent drug. Although the three carbinols appeared in the liver isolates of all species studied, the relative amounts of these metabolites varied across species. With a high, non-physiological ratio of substrate to liver, the 6-carbinol and its glucuronide were the major metabolites in human and monkey, whereas the 6-ketone was a minor metabolite in dog. Containing a stereogenic axis and center, the 6-carbinol existed as diastereomeric atropisomers. Its structure was established by 13C and 1H NMR spectroscopy, mass spectrometry, and comparison to an authentic sample.

The NF-kappaB/Rel family of proteins mediates Abeta-induced neurotoxicity and glial activation

The beta-amyloid peptide (Abeta) is deposited in neuritic plaques which are characteristic features of Alzheimer's disease (AD). Prominent neurodegeneration and glial activation occurs around these plaques leading to the hypothesis that Abeta may play a causative role in the neuronal loss and the inflammatory response associated with AD. Here we show that Abeta-induced toxicity of cultured fetal rat cortical neurons is associated with internucleosomal DNA fragmentation beginning just 6 h after neurons are exposed to Abeta. Additionally, constitutive NF-kappaB activity readily measured in fetal rat cortical neurons decreases in a concentration- and time-dependent fashion following exposure to Abeta, but there is no corresponding decrease in NF-kappaB mRNA or protein (p65). An upregulation of both IkappaB alpha protein and mRNA which occurs in cortical neurons exposed to Abeta may be responsible for retaining NF-kappaB in the cytoplasm accounting for the observed decrease in activated NF-kappaB. The latter is supported by the observation that pretreatment of cortical cultures with an antisense oligonucleotide to IkappaBalpha mRNA is neuroprotective. In contrast to cortical neurons, exposure of rat primary astroglial cultures to Abeta results in a concentration- and time-dependent activation of NF-kappaB with subsequent upregulation of IL-1beta and IL-6. Our data suggest that Abeta-induced neurotoxicity as well as astrocyte activation may be medicated by the NF-kappaB/Rel family of proteins, and thus alterations in NF-kappaB-directed gene expression may contribute to both the neurodegeneration and inflammatory response which occur in AD.

C/EBPepsilon is a myeloid-specific activator of cytokine, chemokine, and macrophage-colony-stimulating factor receptor genes

C/EBPepsilon is a member of the CCAAT/enhancer binding protein family of basic region/leucine zipper transcriptional activators. The C/EBPepsilon protein is highly conserved between rodents and humans, and its domain structure is very similar to C/EBPalpha. In mice C/EBPepsilon mRNA is only detected in hematopoietic tissues, including embryonic liver and adult bone marrow and spleen. Within the hematopoietic system, C/EBPepsilon is expressed primarily in myeloid cells, including promyelocytes, myelomonocytes, and their differentiated progeny. To identify potential functions of C/EBPepsilon, cell lines over-expressing the C/EBPepsilon protein were generated in the P388 lymphoblastic cell line. In contrast to the parental cell line, C/EBPepsilon-expressing cell lines displayed lipopolysaccharide-inducible expression of the interleukin-6 and monocyte chemoattractant protein 1 (MCP-1) genes as well as elevated basal expression of the MIP-1alpha and MIP-1beta chemokine genes. In the EML-C1 hematopoietic stem cell line, C/EBPepsilon mRNA levels increased as the cells progressed along the myeloid lineage, just preceding activation of the gene encoding the receptor for macrophage-colony-stimulating factor (M-CSFR). M-CSFR expression was stimulated in C/EBPepsilon-expressing P388 cell lines, when compared with either the parental P388 cells or P388 cell lines expressing either C/EBPalpha or C/EBPbeta. These results suggest that C/EBPepsilon may be an important regulator of differentiation of a subset of myeloid cell types and may also participate in the regulation of cytokine gene expression in mature cells.

Molecular characterization of pyruvate carboxylase deficiency in two consanguineous families

Pyruvate carboxylase (PC) is a biotinylated mitochondrial enzyme that catalyzes the conversion of pyruvate to oxaloacetate. Children with inborn errors of PC metabolism have lactic acidosis, hypoglycemia, and mental retardation. The variable severity of the clinical phenotype is dependent on both genetic and environmental factors. Two consanguineous families with moderate forms of PC deficiency were characterized at the biochemical and molecular levels. In both families, the probands were found to have low PC activity (range, 2-25% of control) in blood lymphocytes and skin fibroblasts associated with either diminished or normal protein levels. In the first case, sequencing of patient-specific PC cDNA demonstrated a T to C substitution at nucleotide 434, which causes a valine to alanine change at amino acid residue 145. Direct sequencing of the parents showed that they are heterozygous for this mutation. In the second family, a brother and sister had mental retardation and episodes of severe lactic/ketoacidosis in early childhood. In these cases, a C to T substitution at nucleotide 1351 results in a cysteine for arginine substitution at amino acid residue 451; the parents were also found to be heterozygous for this mutation. In both families, no other mutations were found, and both substitutions occurred in relatively conserved amino acid residues. These mutations, located in the biotin carboxylase domain, provide a unique opportunity to analyze how natural occurring mutations affect PC function.

Superoxide anion from the adventitia of the rat thoracic aorta inactivates nitric oxide

The purpose of this study was to determine whether superoxide anion is produced endogenously in the rat aortic adventitia and whether sufficient superoxide anion is produced to interfere with the response of the rat aorta to nitric oxide. Relaxation was measured in rings of the rat thoracic aorta, which were oriented so that the adventitial or luminal surface could be preferentially exposed to nitric oxide or sodium nitroprusside. To accomplish this, the rings were mounted (1) with the adventitia facing outward, (2) with the adventitia facing inward after inverting, or (3) with the adventitia facing outward after inverting twice (to control for the inverting procedure). The relaxation to nitric oxide, but not to sodium nitroprusside, was less in rings with the adventitia facing outward compared with those in which it faced inward. In contrast, the response to nitric oxide via either surface was similar when extracellular superoxide anion was scavenged with superoxide dismutase. Incubation of rings with nitro blue tetrazolium (NBT) resulted in blue formazan staining of the adventitia, and lucigenin chemiluminescence was significantly greater when detected from the adventitial compared with the intimal aspect of the artery. The reduction of NBT in intact aortic rings was 30+/-2 pmol x min(-1) x mg(-1) and was significantly decreased by superoxide dismutase to 19+/-2 pmol x min(-1) x mg(-1) and by a synthetic superoxide dismutase mimic, Euk-8, to 11+/-2 pmol x min(-1) x mg(-1). The NADPH oxidase inhibitor, diphenyleneiodonium, decreased NBT reduction to 9+/-1 pmol x min(-1) x mg(-1), whereas inhibitors of xanthine oxidase, mitochondrial oxidases, and nitric oxide synthase were ineffective. Immunohistochemical staining indicated the localization of NADPH oxidase proteins gp91phox, p22phox, p47phox, and p67phox almost exclusively in the adventitia of the rat aorta with no substantial staining in the media. These results indicate that NADPH oxidase located in the adventitia of rat thoracic aorta generates sufficient extracellular superoxide anion to constitute a barrier capable of inactivating nitric oxide. This study suggests that adventitial superoxide anion can play a role in the pathophysiology of the arterial wall.

Regulation of vascular type 1 angiotensin II receptor in hypertension and sodium loading: role of angiotensin II

OBJECTIVE

To test the hypotheses that a high sodium intake increases steady state messenger RNA levels of the type 1 angiotensin II receptor in the aorta and mesenteric resistance arteries, and that this increase is mediated by suppression of production of angiotensin II induced by a high sodium intake; and to test the hypotheses that angiotensin II administered at a pressor dose increases steady state messenger RNA levels of the angiotensin II type 1 receptor in the aorta and mesenteric resistance arteries, and that this increase is mediated by activation of angiotensin II type 1 receptors in these vessels.

METHODS

In experiment 1, male Wistar rats were divided into four groups and treated for 2 weeks with a (0.5%) normal sodium diet, a normal-sodium diet plus angiotensin II, a high (4%) sodium diet, or a high-sodium plus angiotensin II. We infused 25 ng/kg per min angiotensin II subcutaneously by using osmotic pumps. In experiment 2, male Wistar rats were divided into four groups and treated for 2 weeks with vehicle, 1 mg/kg per day losartan by oral gavage, 250 ng/kg per min angiotensin II by using an osmotic pump), and losartan plus angiotensin II. Angiotensin II type 1 messenger mRNA was measured with the use of quantitative reverse transcriptase-polymerase chain reaction in the presence of an angiotensin II type 1 receptor mutant complementary RNA as internal standard.

RESULTS

Results from experiment 1 show that body weight and systolic tail-cuff blood pressures did not differ among our four groups (P > 0.05). Angiotensin II type 1 messenger RNA levels of rats in high-salt diet group were 73% (aorta) and 171% (mesenteric resistance arteries) greater than those of rats in normal-salt diet group (P < 0.05). In contrast, angiotensin II type 1 messenger RNA levels both in aorta and in mesenteric resistance arteries of rats in normal-salt diet plus angiotensin II and high-salt diet plus angiotensin II groups did not differ from those of rats in normal-salt diet group. Results from experiment 2 show that systolic blood pressures in rats treated with angiotensin II and with losartan plus angiotensin II were higher than those in rats administered vehicle (P < 0.05). Mean response of arterial pressure to bolus injection of angiotensin II was suppressed in losartan-treated rats compared with that in rats administered vehicle and in rats treated with losartan plus angiotensin II compared with that in rats treated with angiotensin II (P < 0.05). Angiotensin II type 1 messenger RNA levels were higher by 73% (in aorta) and 63% (in mesenteric resistance arteries) in rats treated with angiotensin II than they were in rats administered vehicle (P < 0.05), but not in both aorta and mesenteric resistance arteries in rats treated with losartan and losartan plus angiotensin II versus rats administered vehicle.

CONCLUSION

A high-salt diet increases angiotensin II type 1 messenger RNA levels both in aorta and in mesenteric resistance arteries. This increase is completely suppressed by simultaneous nonpressor infusion of angiotensin II, suggesting that angiotensin II negatively regulates vascular angiotensin II type 1 messenger RNA in normotensive rats. Hypertension induced by pressor infusion of angiotensin II increases angiotensin II type 1 messenger RNA levels both in aorta and in mesenteric resistance arteries. This increase can be prevented by administration of losartan at a nondepressor dose, suggesting that angiotensin II positively regulates vascular angiotensin II type 1 messenger RNA via activation of the angiotensin II type 1 receptor during hypertension.

[High performance liquid chromatographic analysis of monosaccharide composition in lacquer polysaccharide from sap of lac tree]

This paper reports the separation and determination of monosaccharide composition in lacquer polysaccharide (LPS) by HPLC. The five monosaccharides were analyzed on microBondapak NH2 column (300 mm x 7.8 mm i.d. 10 microns) and refractive index detection. The mobile phase was CH3CN-H2O-CH3OH (70:25:5, V/V) flowing at a rate of 1.6 mL/min. These monosaccharides were identified by their retention times and quantitatively determined by their peak areas. LPS samples were hydrolysed with 2.0 mol/L CF3COOH. The linear correlation coefficients were all over 0.9953. The average recoveries of monosaccharides ranged 98.8%-103.6% and relative standard deviations were below 5%. The method is simple, rapid, precise, and has been used satisfactorilly for analysis of the monosaccharides hydrolyzed from LPS, which were isolated from sap of three kinds of Lac tree (Maoba Damu, Maoba Xiaomu and Jianshi) in Hubei province.

Alpha2-macroglobulin attenuates beta-amyloid peptide 1-40 fibril formation and associated neurotoxicity of cultured fetal rat cortical neurons

Beta-amyloid peptides (A beta) are deposited in an aggregated fibrillar form in both diffuse and senile plaques in the brains of patients with Alzheimer's disease. The neurotoxicity of A beta in cultured neurons is dependent on its aggregation state, but the factors contributing to aggregation and fibril formation are poorly understood. In the present study, we investigated whether alpha2-macroglobulin (alpha2M), a protein present in neuritic plaques and elevated in Alzheimer's disease brain, is a potential regulatory factor for A beta fibril formation. Previous studies in our laboratory have shown that alpha2M is an A beta binding protein. We now report that, in contrast to another plaque-associated protein, alpha1-antichymotrypsin, alpha2M coincubated with A beta significantly reduces aggregation and fibril formation in vitro. Additionally, cultured fetal rat cortical neurons are less vulnerable to the toxic actions of aged A beta following pretreatment with alpha2M. We postulate that alpha2M is able to maintain A beta in a soluble state, preventing fibril formation and associated neurotoxicity.

Phosphorylation of steroidogenic acute regulatory protein (StAR) modulates its steroidogenic activity

Steroidogenic acute regulatory protein (StAR) plays a critical role in steroid hormone synthesis. StAR is thought to increase the delivery of cholesterol to the inner mitochondrial membrane where P450scc resides. Tropic hormones acting through the intermediacy of cAMP rapidly increase pregnenolone synthesis, and this rapid steroidogenic response is believed to be due to StAR's action. The StAR protein contains two consensus sequences for phosphorylation catalyzed by protein kinase A that are conserved across all species in which the amino acid sequence of the StAR protein has been determined. We demonstrated that human StAR expressed in COS-1 cells exists in at least four species detectable by two-dimensional gel electrophoresis followed by Western blotting. The two more acidic species disappeared after treatment of the cell extracts with alkaline phosphatase. 32P was incorporated into StAR protein immunoprecipitated from COS-1 cell extracts, and a 10-min treatment with 8-bromo-cAMP increased 32P incorporation into the StAR preprotein. StAR protein generated by in vitro transcription/translation was phosphorylated by the protein kinase A catalytic subunit in the presence of [gamma-32P]ATP. Mutation of potential sites for protein kinase A-mediated phosphorylation at serine 57 and serine 195 to alanines, individually, reduced 32P incorporation from labeled ATP into StAR preprotein produced by in vitro transcription/translation when incubated with protein kinase A catalytic subunit. 32P labeling of StAR protein expressed in COS-1 cells was also reduced when serine 57 or serine 195 were mutated to alanines. A double mutant in which both serine 57 and serine 195 were changed to alanines displayed markedly reduced 32P incorporation. To determine the functional significance of StAR phosphorylation, we tested the steroidogenic activity of the wild-type StAR and mutated StAR proteins in COS-1 cells expressing the human cholesterol side chain cleavage enzyme system. Mutation of the conserved protein kinase A phosphorylation site at serine 57 had no effect on pregnenolone synthesis. However, mutation of the serine residue at 195 resulted in an approximately 50% reduction in pregnenolone production. The S195A mutant construct did not yield the more acidic species of StAR detected in two-dimensional Western blots, indicating that the mutation affected the ability of the protein to be post-translationally modified. Mutation of the corresponding serine residues in murine StAR (Ser56 and Ser194) to alanines yielded results that were similar to those obtained with human StAR; the S56A mutant displayed a modest reduction in steroidogenic activity, whereas the S194A mutant had approximately 40% of the activity of murine wild-type StAR. In contrast to the human S195A mutation, conversion of serine 195 to an aspartic acid residue had no effect on steroidogenic activity, consistent with the idea that a negative charge at this site modulates StAR function. Our observations suggest that phosphorylation of serine 194/195 increases the biological activity of StAR and that this post- or co-translational event accounts, in part, for the immediate effects of cAMP on steroid production.

Rapid and sensitive detection of Chlamydia trachomatis using a ligatable binary RNA probe and Q beta replicase

A simple assay format was developed for the direct detection of C. trachomatis rRNA utilizing ligation of recombinant MDV-1 probe RNA fragments hybridized to 23S rRNA after capture and release from a solid support. Assay background (equivalent to 10(4) targets) was suppressed by blocking sequences in the 5' MDV reporter probe fragment complementary to the 3' fragment by prehybridization of a DNA oligonucleotide. A pair of reporter fragments bearing a deletion within the region, obtained by a hydrid-selection-amplification protocol, yielded a low level of assay background which was reduced to < 2% with a blocker directed against the remaining pairing sequence. This probe set showed a sensitivity of 10(3) molecules of 23S rRNA (> 95% responding) and could detect a single elementary body (EB) of Chlamydia trachomatis or 1-10 EB added to a clinical matrix of pooled negative human cervical swab samples. The time of first appearance of amplification products by real-time fluorescence detection showed a linear response to log increases in the target level over a 10(5)-fold range, permitting the determination of target level within an order of magnitude. The assay showed approximately 10(9)-fold discrimination over Chlamydia pneumonae (TWAR) rRNA. High levels of cultured C. albicans, E. coli, S. aureus, or N. gonorrhoeae had no detectable effect on assay background or the ability to detect a single elementary body.

The Tabby phenotype is caused by mutation in a mouse homologue of the EDA gene that reveals novel mouse and human exons and encodes a protein (ectodysplasin-A) with collagenous domains

Mouse Tabby (Ta) and X chromosome-linked human EDA share the features of hypoplastic hair, teeth, and eccrine sweat glands. We have cloned the Ta gene and find it to be homologous to the EDA gene. The gene is altered in two Ta alleles with a point mutation or a deletion. The gene is expressed in developing teeth and epidermis; no expression is seen in corresponding tissues from Ta mice. Ta and EDA genes both encode alternatively spliced forms; novel exons now extend the 3' end of the EDA gene. All transcripts recovered have the same 5' exon. The longest Ta cDNA encodes a 391-residue transmembrane protein, ectodysplasin-A, containing 19 Gly-Xaa-Yaa repeats. The isoforms of ectodysplasin-A may correlate with differential roles during embryonic development.

Detection of Babesia bovis using a DIG-labeled DNA probe

A plasmid DNA containing the inserted Babesia bovis cDNA clone designated c51A was used to prepare a DNA probe for B. bovis. The purified 0.6 kb specific DNA fragment was labeled by DIG DNA labeling. After denaturation, the probe was hybridised with the blotted target DNA extracted from bovine red blood cells infected with B. bovis or other protozoa or bovine red blood cells plus extra white blood cells. It was found that the probe produced from purified 0.6 kb DNA fragment could detect sample of B. bovis DNA equivalent to 0.015 microliter of 10% whole infected blood. Compared to the same DNA fragment labeled with photobiotin, this new probe is more sensitive giving a darker hybridization signal, a lighter hybridization background and without any non-specific reactions. These results indicated that this DIG-labeled B. bovis C5lA probe could provide a sensitive and specific method to diagnose clinically suspected B. bovis infections and distinguish B. bovis DNA from other haemoprotozoan infections.

Activation of a caspase 3-related cysteine protease is required for glutamate-mediated apoptosis of cultured cerebellar granule neurons

Neurotoxicity induced by overstimulation of N-methyl-D-aspartate (NMDA) receptors is due, in part, to a sustained rise in intracellular Ca2+; however, little is known about the ensuing intracellular events that ultimately result in cell death. Here we show that overstimulation of NMDA receptors by relatively low concentrations of glutamate induces apoptosis of cultured cerebellar granule neurons (CGNs) and that CGNs do not require new RNA or protein synthesis. Glutamate-induced apoptosis of CGNs is, however, associated with a concentration- and time-dependent activation of the interleukin 1beta-converting enzyme (ICE)/CED-3-related protease, CPP32/Yama/apopain (now designated caspase 3). Further, the time course of caspase 3 activation after glutamate exposure of CGNs parallels the development of apoptosis. Moreover, glutamate-induced apoptosis of CGNs is almost completely blocked by the selective cell permeable tetrapeptide inhibitor of caspase 3, Ac-DEVD-CHO but not by the ICE (caspase 1) inhibitor, Ac-YVAD-CHO. Western blots of cytosolic extracts from glutamate-exposed CGNs reveal both cleavage of the caspase 3 substrate, poly(ADP-ribose) polymerase, as well as proteolytic processing of pro-caspase 3 to active subunits. Our data demonstrate that glutamate-induced apoptosis of CGNs is mediated by a posttranslational activation of the ICE/CED-3-related cysteine protease caspase 3.

Regulation of type 1 ANG II receptor in vascular tissue: role of alpha1-adrenoreceptor

Angiotensin II (ANG II) and norepinephrine (NE) are important regulators of vascular function and structure. Recent studies showed that there are multiple interactions between these two potent vasoconstrictor agents. The present experiment was designed to investigate the effect of NE on the expression of the type 1 ANG II receptor (AT1) in the aorta and cultured vascular smooth muscle cells (VSMC) of rats. Rats were subcutaneously infused with either NE (0.5 microg x kg(-1) x min(-1), n = 6) or the alpha1-adrenoreceptor antagonist prazosin (3.5 microg x kg(-1) x min(-1), n = 6) for 2 wk. Body weight and tail cuff systolic blood pressure were not modified compared with the vehicle control (P > 0.05). Northern blot analysis showed that AT1 mRNA levels in aorta were decreased by 38% in NE-treated rats and increased 117% in prazosin-treated rats (P < 0.05) compared with control. To determine whether NE directly regulates expression of vascular AT1 mRNA and AT1 receptor density, Northern blot analysis and radioligand binding experiments were performed in cultured VSMC. Incubation of VSMC with NE (10(-7) M) led to 44% decrease in AT1 mRNA levels (P < 0.05) and 39% decrease in AT1 receptor density (P < 0.05). Prazosin, but not the alpha2-adrenoreceptor antagonist yohimbine, prevented NE-induced decrease in AT1 mRNA and AT1 receptor density in these cells. Taken together, our results indicate that vascular AT1 gene expression and receptor protein are regulated by ambient NE levels, and NE-induced downregulation of AT1 mRNA and receptor protein is mediated, at least in part, by activating alpha1-adrenoreceptors.

Involvement of a caspase-3-like cysteine protease in 1-methyl-4-phenylpyridinium-mediated apoptosis of cultured cerebellar granule neurons

Exposure of various neuronal cells or cell lines to high concentrations of 1-methyl-4-phenylpyridinium (MPP+), the active metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), results in cell death. Recently, it has been reported that low concentrations of MPP+ induce apoptosis in susceptible neurons. We have further characterized MPP+-mediated toxicity of cultured cerebellar granule neurons (CGNs) and found that exposure of CGNs to relatively low concentrations of MPP+ results in apoptosis, whereas higher concentrations result in necrosis. Cotreatment of CGNs with MPP+ and the tetrapeptide inhibitor of caspase-3-like proteases, acetyl-DEVD-CHO, markedly attenuates apoptotic but not necrotic death of these neurons. The more specific inhibitor of caspase-1-like proteases, acetyl-YVAD-CHO, however, was ineffective against MPP+ neurotoxicity. Moreover, cytoplasmic extracts prepared from MPP+-treated CGNs contain markedly increased protease activity that cleaves the caspase-3 substrate acetyl-DEVD-p-nitroaniline. Finally, the cytoplasmic concentration of the apoptogenic protein cytochrome c was increased in a time-dependent fashion in MPP+-treated CGNs before the onset of apoptosis. Our data confirm that the neurotoxicity of MPP+ is due to both necrosis and apoptosis and suggest that the latter is mediated by activation of a caspase-3-like protease.

Intracellular targeting of exoenzyme S of Pseudomonas aeruginosa via type III-dependent translocation induces phagocytosis resistance, cytotoxicity and disruption of actin microfilaments

Exoenzyme S (ExoS) is an ADP-ribosyltransferase secreted by the opportunistic pathogen Pseudomonas aeruginosa. The amino-terminal half of ExoS exhibits homology to the YopE cytotoxin of pathogenic Yersinia. Recently, YopE was found to be translocated into the host cell by a bacteria-cell contact-dependent mechanism involving the ysc-encoded type III secretion system. By using an approach in which exoS was expressed in different strains of Yersinia, including secretion and translocation mutants, we could demonstrate that ExoS was secreted and translocated into HeLa cells by a similar mechanism to that described previously for YopE. Similarly to YopE, the presence of ExoS in the host cell elicited a cytotoxic response, correlating with disruption of the actin microfilament structure. A similar cytotoxic response was also induced by a mutated form of ExoS with a more than 2000-fold reduced ADP-ribosyltransferase activity. However, the enzymatically active ExoS elicited a more definite rounding up of the HeLa cells, which also correlated with decreased viability of the cells after prolonged infection compared with cells infected with strains expressing mutated ExoS or YopE. This suggests that ExoS can act through two different mechanisms on the host cell. The expression of ExoS by Yersinia also mediated an anti-phagocytic effect on macrophages. In addition, we present evidence that extracellularly located P. aeruginosa is able to target ExoS into eukaryotic cells. Taken together, our data suggest that P. aeruginosa, by analogy with Yersinia, targets virulence proteins into the eukaryotic cytosol via a type III secretion-dependent mechanism as part of an anti-phagocytic strategy.

Regulation of type 1 angiotensin II receptor in adrenal gland: role of alpha1-adrenoreceptor

We have previously shown that sodium restriction upregulates the genes encoding angiotensin II receptor (AT1) subtypes, AT1A and AT1B, in the adrenal gland and that this upregulation is mediated by activation of the AT1 receptor. There are multiple interactions between the renin-angiotensin and the adrenergic nervous systems; thus, we conducted the present experiment to investigate whether low sodium-induced upregulation of adrenal AT1A and AT1B is modulated by the alpha1-adrenoreceptor. Seven-week-old male Wistar rats were divided into four groups and given normal sodium diet (0.5%, NS), NS+prazosin (3.5 microg x kg(-1) x min(-1) by osmotic pump), low sodium diet (0.07%, LS), or LS+prazosin. Body weight and mean arterial pressure were not modified over the 2 weeks of treatment (P>.05). Pressor responses to bolus injection of the alpha1-agonist phenylephrine were inhibited in both prazosin groups, compared with NS and LS rats (P<.05). Adrenal AT1A mRNA, determined by Northern blot analysis, was increased in LS (P<.05) but not in NS+prazosin (P>.05), compared with NS. Prazosin enhanced the LS-induced increase of AT1A mRNA (P<.05). Adrenal AT1B mRNA was increased in both LS and NS+prasozin rats, compared with NS rats (P<.05). Prazosin also enhanced the LS-induced increase in AT1B mRNA (P<.05). Therefore, blockade of alpha1-adrenoreceptor results in an enhancement of LS-induced upregulation of adrenal mRNA for AT1A and AT1B. These data suggest that the sympathetic nervous system exerts an inhibitory action, via activation of the alpha1-adrenoreceptor, on AT1A and AT1B gene expression in the adrenal gland during sodium depletion.

alpha2-Macroglobulin as a beta-amyloid peptide-binding plasma protein

The beta-amyloid peptide (A beta) is a normal proteolytic processing product of the amyloid precursor protein, which is constitutively expressed by many, if not most, cells. For reasons that are still unclear, A beta is deposited in an aggregated fibrillar form in both diffuse and senile plaques in the brains of patients with Alzheimer's disease (AD). The factor(s) responsible for the clearance of soluble A beta from biological fluids or tissues are poorly understood. We now report that human alpha2-macroglobulin (alpha2M), a major circulating endoproteinase inhibitor, which has recently been shown to be present in senile plaques in AD, binds 125I-A beta(1-42) with high affinity (apparent dissociation constant of 3.8 x 10(-10) M). Approximately 1 mol of A beta is bound per mole of alpha2M. Both native and methylamine-activated alpha2M bind 125I-A beta(1-42). The binding of 125I-A beta(1-42) to alpha2M is enhanced by micromolar concentrations of Zn2+ (but not Ca2+) and is inhibited by noniodinated A beta(1-42) and A beta(1-40) but not by the reverse peptide A beta(40-1) or the cytokines interleukin 1beta or interleukin 2. alpha1-Antichymotrypsin, another plaque-associated protein, inhibits both the binding of 125I-A beta(1-42) to alpha2M as well as the degradation of 125I-A beta(1-42) by proteinase-activated alpha2M. Moreover, the binding of 125I-A beta(1-42) to alpha2M protects the peptide from proteolysis by exogenous trypsin. These data suggest that alpha2M may function as a carrier protein for A beta and could serve to either facilitate or impede clearance of A beta from tissues such as the brain.

The trends in histological types of lung cancer during 1980-1988, Guangzhou, China

Five thousand five hundred and forty six cases of all lung cancer patients who died during 1980-1988 in Guangzhou, China were investigated retrospectively with a standardized 31-item questionnaire administered to their next of kin. The data of 1093 lung cancer patients(20%, 1093/5546) who had a histological record was analyzed to investigate the changes in histological types and the possible etiologic causes. The difference between the lung cancer deaths with and without histological record is not significant in age, location (peripheral or central) of tumour and status of occupation (P > 0.05), but the difference in sex is significant (P < 0.01). We analyzed the data of 1093 cases by sex and by 3-year period. There had been a shift in the histology pattern with an increase in the percentage of adenocarcinoma (P = 0.0011) and a decrease in percentage of squamous cell carcinoma (P = 0.0027) in males, inversely, there has been an absolute and a relative decrease of percentage in adenocarcinoma in females (P = 0.0028). The percentage of smokers, age of starting to smoke and type of tobacco smoking were nearly constant in both sexes during the studied periods. The pack-years of smoking decreased in males (P = 0.0396), and seemed increase in females (P = 0.1576, no significance). The analysis of occupation and dietary habits among 5546 cases were performed. The proportion of housewives decreased with time (P < 0.001) while the percentage of chemists in females increased (P < 0.001) with time. The dietary habits are changing with an increase in roast food intake for males (P = 0.0055) and in vegetable intake for males (P < 0.0001), females (P < 0.0001), and for patients with lung squamous cell carcinoma and adenocarcinoma in both sexes (P < 0.001). Perhaps the changes in pack-years of smoking may be responsible for the percentage change of lung cancer histological types observed in our study. The role that changes in dietary habits and status of occupations play in the changing trends of lung cancer histological types in our study need further study.

Proviral integrations at the Evi5 locus disrupt a novel 90 kDa protein with homology to the Tre2 oncogene and cell-cycle regulatory proteins

Evi5 is a common site of retroviral integration in T-cell lymphomas of AKXD mice. Mapping studies have localized Evi5 to a region approximately 18 kb upstream of another common viral integration site, Gfi1, on mouse chromosome 5 (Liao X, Jenkins NA and Copeland NG, (1995a). J. Virol., 69, 7132-7137). Gfi1 encodes a zinc finger transcription factor involved in interleukin-2 signaling. To determine if Evi5 encodes a gene separate from Gfi1 that might also be involved in T-cell disease, we have searched within the Evi5 locus for novel transcripts. A 6.0 kb transcript was identified in these studies that spans the Evi5 locus and is disrupted by viral integration at Evi5. This transcript is expressed in all embryonic and adult mouse tissues examined. While blast searches indicated that Evi5 is a novel gene, homologies were detected between Evi5 and a known oncogene, Tre2, as well as mammalian and yeast cell cycle regulatory proteins. Evi5 thus encodes a gene separate from Gfi1 that may also be involved in T-cell disease.

Cloning and expression of a rat brain interleukin-1beta-converting enzyme (ICE)-related protease (IRP) and its possible role in apoptosis of cultured cerebellar granule neurons

Several members of the IL-1beta-converting enzyme (ICE) family of proteases recently have been implicated in the intracellular cascade mediating the apoptotic death of various cell types. It is unclear, however, whether ICE-related proteases are involved in apoptosis of mammalian neurons and, if so, how they are activated. Here we report the cloning of an ICE-related protease (IRP) from rat brain, which displays strong sequence identity to human CPP32. In situ hybridization histochemistry reveals that this IRP mRNA is expressed in neuron-enriched regions of the developing and adult rat brain but is profoundly downregulated in the adult (compared with developing) brain. To investigate whether this IRP is involved in the death of neurons in the developing brain, we studied IRP expression in cultured cerebellar granule neurons. In cultured cerebellar granule neurons, reduction of extracellular K+ reliably induces apoptosis and stimulates overexpression of IRP mRNA. The latter is especially prominent 4 hr after switching from high K+ to low K+ medium. The expression of IRP mRNA was maintained at this level for at least 8 hr and was followed by apoptotic death of these neurons. Induction of IRP mRNA and cell death are blocked completely by adding depolarizing concentrations of K+ </=90 min after switching to low K+ medium (i.e., before the commitment point for apoptosis) and partially blocked by brain-derived neurotrophic factor (BDNF), which also partially rescues granule neurons from low K+-induced apoptosis. In addition, overexpression of IRP cDNA in HeLa cells results in cell death accompanied by strong internucleosomal cleavage of DNA, a typical feature of apoptosis. Finally, we detected cleavage of the putative death substrate poly (ADP-ribose) polymerase (PARP), beginning 8 hr after changing from high K+ to low K+ medium, coinciding with the time course of induced expression of the IRP gene. Our data suggest that transcriptional activation of IRP could be one of the mechanisms involved in the apoptotic death of cerebellar granule neurons.

Reduced responsiveness of hypercholesterolemic rabbit aortic smooth muscle cells to nitric oxide

The response to nitric oxide of intracellular free Ca2+ levels, measured by fura 2 fluorimetry, and cyclic GMP, measured by RIA, was evaluated on smooth muscle cells of the thoracic aorta in primary culture from normal and cholesterol-fed rabbits. Relaxation to acetylcholine and nitric oxide was also determined in isolated rings of aorta. After 10 weeks of high-cholesterol diet, the intact aorta relaxed less to both acetylcholine and nitric oxide. In cultured cells from hypercholesterolemic rabbits, intracellular Ca2+ oscillated, and the mean Ca2+ levels were approximately twofold greater than in normal aortic cells. Nitric oxide failed to affect basal Ca2+ in either cell type. The peak and sustained rise in intracellular Ca2+ induced by angiotensin II (10(-7) mol/L) were similar in the two cell types. However, nitric oxide (10(-10) to 10(-6) mol/L) decreased the sustained Ca2+ levels to a significantly smaller extent in cells from cholesterol-fed rabbits. In addition, in cells from hypercholesterolemic rabbits, nitric oxide added before angiotensin II inhibited to a smaller degree the transient increase in intracellular free Ca2+ caused by angiotensin II in the nominal absence of extracellular Ca2+, as well as the increase in Ca2+ associated with the addition of extracellular Ca2+. Measurements of fura 2 quenching caused by Mn2+ influx confirmed that nitric oxide inhibited the entry of extracellular divalent cations significantly less in cells from hypercholesterolemic rabbits. Basal levels of cyclic GMP were significantly less than normal, and nitric oxide increased levels of cyclic GMP to a significantly smaller degree in cells from cholesterol-fed rabbits. These data indicate a substantial resistance to nitric oxide action in aortic smooth muscle cells of cholesterol-fed rabbits. This observation is consistent with the notion that resistance of smooth muscle cells to nitric oxide contributes to abnormal endothelium-dependent vasodilation during hypercholesterolemia and can play a role in the pathogenesis of atherosclerosis.

1H MAS and 1H[23Na] double resonance NMR studies on the modification of surface hydroxyl groups of gamma-alumina by sodium

The modification of surface hydroxyl groups with sodium in a series of Na2CO3-gamma-Al2O3 catalysts was investigated as a function of both the Na2CO3 loading and the calcination temperature by means of 1H magic angle spinning (MAS) and 1H(23Na) spin-echo double resonance NMR techniques. The 1H NMR experiments revealed that sodium ions are homogeneously distributed over the alumina surface and closely coordinated with the surface hydroxyl groups. In the catalysts calcined at 250 degrees C, the acidic hydroxyl groups (with a chemical shift of 2.0 ppm) are preferentially associated with sodium ions at low Na2CO3 coverages (5 and 10%), while both the acidic and the basic (0 ppm) hydroxyl groups are accessible for sodium ions at high coverages (15 and 20%). The coordination causes a low-field shift of about 2 ppm in the 1H MAS spectra, and a broad signal at 4.5 ppm appears. It is interesting that the 4.5 ppm signal is completely suppressed in the 1H(23Na) MAS experiments, providing direct evidence that a strong interaction exists between adsorbed sodium ions and the surface hydroxyl groups. Increasing the calcination temperature to 450 degrees C results in preferential removal of the acidic hydroxyl groups, and only the most basic hydroxyl groups remain when the calcination temperature is raised to 600 degrees C. This is attributed to the formation of the coordinated species. [formula: see text] which enhances the acidity of the surface hydroxyl groups and prompts their dehydroxylation, especially at high calcination temperature. Correlation of the 1H MAS NMR results and catalytic activity measurements indicates that the basic hydroxyl groups are essential for the carbonyl sulfide hydrolysis reaction.

Regulation of angiotensin type 1 receptor and its gene expression: role in renal growth

Low sodium intake has been demonstrated to upregulate the gene expression of the predominant renal type 1 angiotensin II (Ang II) receptor (AT1), the AT1A subtype. The study presented here tests the hypothesis that the upregulation of renal AT1 mRNA induced by sodium depletion occurs conjointly with an elevation of the AT1 receptor that modulates renal growth. Seven-week-old male Wistar rats were divided into four groups and treated for 2 wk with normal sodium diet, normal sodium diet plus 3 mg/kg/day losartan, low sodium diet, or low sodium diet plus losartan. Body weight and MAP were not significantly different among the four groups. Plasma renin activity was significantly elevated by losartan treatment, low salt intake, or a combination of the two, compared with the plasma renin activity of the controls. Northern blot analysis indicated that renal AT1 mRNA levels were significantly increased-183% by losartan, 212% by low salt intake, and 227% by the combination of the two-compared with their levels in controls. Radioligand binding assays revealed that AT1 receptors were significantly increased by low salt intake but were significantly decreased by losartan treatment. Renal AT1 receptor binding in the rats subjected to sodium depletion plus losartan did not differ from that in control rats. Kidney weight, kidney weight/body weight ratio, and renal DNA and protein content were not altered by sodium depletion but were significantly lowered by losartan treatment with both normal and low sodium intake, compared with those of controls. The protein/DNA ratio was not significantly different among the four groups. Blockade of renal AT1 receptors with losartan was found to retard normal renal growth, indicating that Ang II is required for normal renal development. Low sodium intake was found to increase mRNA and expression of the renal AT1 receptor but to have no effect on renal growth, suggesting that an increase in renal mass above a normal level requires the activation of multiple factors. Blockade of the AT1 receptor by losartan was found to upregulate AT1 mRNA but to down-regulate the AT1 receptor, suggesting that AT1 receptor-mediated intracellular events are necessary to sustain functional AT1 receptor expression in the kidney.

Regulation of growth of the adrenal gland in DOC-salt hypertension. Role of angiotensin II receptor subtypes

To investigate the role of the renin-angiotensin system in the regulation of adrenal growth in deoxycorticosterone (DOC)-salt hypertensive rats, and the adrenal gene expression of angiotensin AT1 and AT2 receptors, three groups of uninephrectomized rats + DOC pellet + 0.9% NaCl were given water (DOC), losartan (DOC-L), or ramipril (DOC-R) by gavage. Controls had sham surgery and water gavage. Tail-cuff systolic and mean intra-arterial blood pressures were significantly higher in the three DOC groups than in controls and not different among the groups. Adrenal weight of DOC was slightly but not significantly greater than that of controls, while those of DOC-L and DOC-R were greater than that of controls (P < .01). Northern blots showed that AT1 and AT2 gene expression was significantly reduced in DOC (by 33% and 60%), while that of AT1 (but not AT2) was significantly reduced further (versus control and DOC) in DOC-L and DOC-R. There were negative correlations between adrenal weight and AT1 (r = -.80, P < .0001) or AT2 (r = -.60, P < .005). We conclude that DOC-salt hypertension downregulates adrenal AT1 and AT2 gene expression by different mechanisms. Removal of the effects of angiotensin by losartan or ramipril downregulates AT1 further and promotes adrenal growth, indicating the presence of an AT1-mediated growth-inhibitory action of angiotensin II on the adrenal gland. These observations constitute an additional example of a growth-inhibitory role for the AT1 receptor, opposite to its more common growth-promoting actions in other organs and tissues.

Pancreatic microcirculation in the monkey with special reference to the blood drainage system of Langerhans islets: light and scanning electron microscopic study

The microcirculation of the pancreas in 20 monkeys (Macaca mulatta) was further studied by scanning electron microscopy (SEM) of vascular corrosion casts and light microscopy (LM) of Chinese ink-injected/cleared tissues. The results revealed that 91% of islets observed received arterial blood from the terminal branches of the intralobular arteries--the afferent arterioles, and 9% received no arterial blood, being entirely supplied by the efferent vessels of the intermediate or large islets. Some islets received blood from the translobular afferent arterioles of the adjacent lobule. Two patterns of islet drainage channels with different features in the monkey were demonstrated in our study. These patterns might be termed as continuous or convergent portal vessels. All islets possessed continuous portal vessels, 7-8 microns in diameter, which ran a short distance (approximately 100 microns) and then drained into the peri-islet acinar region, forming a typical continuous insulo-acinar portal system. About 21% of the islets possessed one or two convergent portal vessels, occasionally more. This was first observed in the monkey. These vessels were relatively long and/or thick and drained into different regions: (1) the acinar region far from the islet in the lobule, forming a convergent insulo-acinar portal system, (2) crossed the interlobular septum into an adjacent lobule where sometimes no islet existed and then drained into the exocrine acinar region, forming a translobar convergent insulo-acinar portal system, (3) drained into an adjacent small islet through the insulo-insular drainage vessels--one part of the drainage system of the islets. Translobular vascular anastomoses observed between the microcirculation of pancreatic lobules in the monkey formed a new arrangement of pancreatic microcirculation-translobular pancreatic microcirculation. The functional and clinical significance of the pancreatic portal circulation and translobular circulation is discussed in this report.

Localization of the gene responsible for the op (osteopetrotic) defect in rats on chromosome 10

Osteopetrosis, a skeletal disorder of inadequate bone resorption with an abnormal increase in skeletal mass, results from a variety of independent single gene mutations that affect osteoclast differentiation and/or function. The osteopetrotic defect, op, is one of four spontaneous, nonallelic mutations in rats that result in osteopetrosis. In intercross progeny of (BN/SsN x LEW/SsN. +/op) F1 carriers, we mapped this locus by linkage analysis with microsatellite markers to rat chromosome 10. The linkage group contained, as well as op, 15 anonymous DNA loci and 9 DNA loci associated with genes (interleukin-3, myosin heavy chain [skeletal, embryonic], asialoglycoprotein receptor [hepatic lectin]-1, vesicle-associated membrane protein [synaptobrevin-2], sex hormone binding globulin, aldolase C, nitric oxide synthase [inducible], erythroblastic leukemia avian viral oncogene homolog-2, and proline-rich protein). The markers for these loci include nine not previously reported. The op locus mapped to the end of the chromosome 10 linkage group, within 1 cM of the anonymous DNA locus, D10Mit6. Based on its location, the op gene is likely to be distinct from seven described mutations in mice as well as three other mutations in rats. These results may permit a positional cloning strategy to be undertaken to identify the gene and mutation underlying the op defect.