Bond strength of composite to sound and artificial carious dentin

PURPOSE

To determine the in vitro bond strength of a composite (Herculite XRV) to sound dentin and artificial carious lesions in dentin.

MATERIALS AND METHODS

Buccal and lingual surfaces from extracted human molar teeth were ground to expose sound dentin surfaces. The buccal surface was maintained as sound dentin, while an artificial carious lesion was created in the lingual surface using an acidified gelatin gel. A bonding agent (Optibond) was applied to both buccal and lingual surfaces with and without prior etching with 37.5% phosphoric acid. The composite was applied and debonded under tension after 24 hours in water at 37 degrees C.

RESULTS

Both sound dentin (23.1 MPa) and etched sound dentin (22.2 MPa) had similar bond strengths, whereas artificial carious lesions in dentin that had been etched (11.8 MPa) and non-etched dentin lesions (8.8 MPa) had significantly lower bond strengths. Adhesive failures were greatest for dentin lesions (60-95%) and least for sound dentin(40-50%). Etching with phosphoric acid did not improve the bond strength of composite to sound dentin or artificial carious lesions in dentin.

Slow conversions among subconductance states of cystic fibrosis transmembrane conductance regulator chloride channel

The cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel exhibits multiple subconductance states. To study the regulation of conductance states of the CFTR channel, we expressed the wild-type CFTR protein in HEK 293 cells, and isolated microsomal membrane vesicles for reconstitution studies in lipid bilayer membranes. A single CFTR channel had a dominant conductance of 7.8 pS (H), plus two sub-open states with conductances of approximately 6 pS (M) and 2.7 pS (L) in 200 mM KCl with 1 mM MgCl2 (intracellular) and 50 mM KCl with no MgCl2 (extracellular), with pH maintained at 7.4 by 10 mM HEPES-Tris on both sides of the channel. In 200 mM KCl, both H and L states could be measured in stable single-channel recordings, whereas M could not. Spontaneous transitions between H and L were slow; it took 4.5 min for L-->H, and 3.2 min for H-->L. These slow conversions among subconductance states of the CFTR channel were affected by extracellular Mg; in the presence of millimolar Mg, the channel remained stable in the H state. Similar phenomena were also observed with endogenous CFTR channels in T84 cells. In high-salt conditions (1.5 M KCl), all three conductance states of the expressed CFTR channel, 12.1 pS, 8.2 pS, and 3.6 pS, became stable and seemed to gate independently from each other. The existence of multiple stable conductance states associated with the CFTR channel suggests two possibilities: either a single CFTR molecule can exist in multiple configurations with different conductance values, or the CFTR channel may contain multimers of the 170-kDa CFTR protein, and different conductance states are due to different aggregation states of the CFTR protein.

Effects of chelating agents on testicular toxicity in mice caused by acute exposure to nickel

N-Benzyl-D-glucaminedithiocarbamate (BGD), diethyldithiocarbamate (DDTC), dihydroxyethyldithiocarbamate (DHED), trans-1,2-cyclohexanediamine N,N,N',N'-tetraacetic acid (CDTA), and meso-2,3-dimercaptosuccinic acid (DMSA) were studied for their protective effects against the testicular toxicity in mice induced by acute exposure to nickel (Ni). Mice were injected intraperitoneally with NiCl2 (5 mgNi/kg) and 30 min or 24 h later, they were injected intraperitoneally with chelating agents (400 mumol/kg). Ni injection increased lipid peroxidation and concentrations of Ca and Fe in the testes, liver, and kidney, and decreased the testicular weight and the fertility rate. At 30 min after Ni treatment, the chelating agents other than CDTA effectively depressed Ni concentration in the testes. At 24 h after Ni treatment, DMSA, BGD, and DDTC were effective in mobilizing Ni from the testes. DMSA, BGD, and CDTA significantly prevented the increase in the lipid peroxidation, the increase in the concentrations of Ca and Fe in the testes, liver, and kidney, and the decrease in the fertility rate caused by Ni injection. Treatment with DMSA or BGD was more effective than that with the others in decreasing the testicular Ni concentration, resulting in effective protection against Ni-induced testicular damage.

Human myeloid cell nuclear differentiation antigen binds specifically to nucleolin

The human myeloid cell nuclear differentiation antigen (MNDA) is a nuclear protein expressed specifically in cells of the myelomonocytic lineage and regulated by interferon alpha in a cell-specific fashion. MNDA is also a member of a family of interferon-regulated genes of unknown function. In an effort to elucidate the function of MNDA, three techniques (affinity purification, coimmunoprecipitation, and protein blot assay) were used to characterize its specific protein binding activities. Microsequence analysis showed that MNDA bound the 100 kDa nucleolin protein. The identification of nucleolin was confirmed by immunoreaction with specific antibodies. MNDA contains motifs which could account for specific binding to nucleolin. Nucleolin binds other macromolecules and exhibits features consistent with roles in signal transduction, production of ribosomes, nuclear matrix structure, and regulation of transcription. The present results indicate that the function of MNDA is most likely related to interactions with other proteins. Through these associations, MNDA could contribute cell/lineage- and differentiation-specific limits to the function of ubiquitous proteins such as nucleolin. Further analysis of MNDA protein binding could be critical to elucidating the function of MNDA and could contribute to understanding the function of the products of other members of this interferon-inducible family of genes.

[Effect of buspirone, a serotonergic 5-HT-1A agonist in cerebellar ataxia: a pilot study. Preliminary communication]

We propose a serotonergic hypothesis for cerebellar ataxia. The levorotatory form of 5 hydroxytryptophan has been shown to be partially active in subtypes of cerebellar ataxia, including cerebellar cortical atrophy (CCA). Buspirone, a 5-HT1A agonist usable in human medicine, has been studied in a group of 14 patients with cerebellar cortical atrophy. Patients were given Buspirone for 2 months. The evaluation of cerebellar ataxia was made by a semi-quantitative scale, 10 fully quantitative measures and measurements of the sway path and sway area of the center of gravity at posturography. The primary endpoints were the modifications of the ataxia scores. At 2 months, the decrease of the ataxia scores was significant, both in the intention-to-treat (14 cases) and target (11 cases) populations. In the target population, secondary endpoints like the time measurements for pronouncing a standard sentence, the time for drawing a ladder and posturographic parameters were significantly improved; the mean global ataxia score was improved by 37.4%. These preliminary data might confirm a link between cerebellar ataxia and the metabolism of serotonin.

Intracellular loop between transmembrane segments IV and V of cystic fibrosis transmembrane conductance regulator is involved in regulation of chloride channel conductance state

The cystic fibrosis transmembrane conductance regulator (CFTR) contains two membrane-spanning domains; each consists of six transmembrane segments joined by three extracellular and two intracellular loops of different length. To examine the role of intracellular loops in CFTR channel function, we studied a deletion mutant of CFTR (delta 19 CFTR) in which 19 amino acids were removed from the intracellular loop joining transmembrane segments IV and V. This mutant protein was expressed in a human embryonic kidney cell line (293 HEK). Fully mature glycosylated CFTR (approximately 170 kDa) was immunoprecipitated from cells transfected with wild-type CFTR cDNA, while cells transfected with the mutant gene expressed only a core-glycosylated form (approximately 140 kDa). The chloride efflux rate (measured by 6-methoxyl-N-(3-sulfopropyl) quinolinium SPQ fluorescence) from cells expressing wild-type CFTR increased 600% in response to forskolin. In contrast, delta 19 CFTR-expressing cells had no significant response to forskolin. Western blotting performed on subcellular membrane fractions showed that delta 19 CFTR was located in the same fractions as delta F508 CFTR, a processing mutant of CFTR. These results suggest that delta 19 CFTR is located in the intracellular membranes, without reaching the cell surface. Upon reconstitution into lipid bilayer membranes, delta 19 CFTR formed a functional Cl- channel with gating properties nearly identical to those of the wild-type CFTR channel. However, delta 19 CFTR channels exhibited frequent transitions to a 6-picosiemens subconductance state, whereas wild-type CFTR channels rarely exist in this subconductance state. These data suggest that the intracellular loop is involved in stabilizing the full conductance state of the CFTR Cl- channel.

Computerized microimage analysis of age-related changes of the human sinoatrial node

This paper reports the age-related changes in the histological features of the sinoatrial node (SAN). The hearts of 106 persons dying at different ages (2 days-83 years), without clinical or pathological evidence of cardiac disease, were taken and divided into seven age-groups. Serial sections with a thickness of 2 microns, parallel to the long axis of the SAN, were prepared. Sections with the maximal area of the SAN were stained with hematoxylin/eosin (H & E) and Betty's method. The largest area of SAN were calculated by a computerized microimage analysis system. The age-related changes of the human SAN were discussed.

Nitro containing L-arginine analogs interfere with assays for nitrate and nitrite

We evaluated the effect of in vivo and in vitro administration of nitro-containing and nitro-deficient L-arginine-derived nitric oxide (NO) synthase inhibitors on the measurement of NO in plasma, urine and HEPES buffered physiologic salt solution (PSS) by ozone chemiluminescence and by the modified Griess reaction. In vivo administration of 1, 5, 25, 40 or 50 mg/kg of NG-nitro-L-or D-arginine methyl ester (LNAME, DNAME), NG-nitro-L-arginine (LNA) or aminoguanidine (AG) to rats and mice increased NO in urine and plasma as determined by chemiluminescence using 2.3% vanadium chloride in 2N HCI at 100 degrees C as the redox reagent. In vivo administration of 1 and 10 mg/kg/day of NG-imino-ethyl-L-ornithine (LNIO) or 3 amino-1,2,4 triazine (AT) reduced plasma and urine NO. Addition of LNAME, DNAME and LNA (100 nM to 1 mM) to the redox solution produced a concentration response curve for NO in the chemiluminescence assay similar to that produced by standard solutions of sodium nitrite and nitrate. LNMMA produced a small NO signal but only at concentrations equal to or exceeding 0.1 mM. LNIO, AT and AG did not give any NO signal even at concentrations exceeding 1 mM. Conversion of plasma or urine nitrate to nitrite with cadmium gave elevated values of plasma nitrite by the Greiss assay when LNAME or LNA was the NO synthase inhibitor. We conclude that in vivo and in vitro use of LNAME and LNA and in vivo use of high doses of aminoguanidine interfere with the assay of NO2- and NO3- with the modified Griess reaction and with chemiluminescence. We suggest that LNAME and LNA not be used in vivo or in vitro when total RNI is measured with these assays.

Synthesis, characterization and antibacterial activity of novel Fe(III), Co(II), and Zn(II) complexes with norfloxacin

Three novel complexes of norfloxacin (abbreviated as NFL), [M(NFL)2(H2O)2]Cl3.6H2O, (M = Fe, Co), and [Zn(NFL)2]Cl2.7H2O, have been prepared. The compounds were characterized by IR, UV-Vis, NMR spectra, molar conductivity, and elemental analyses. In all of the complexes, the ligand NFL was coordinated through two carboxyl oxygen atoms. Octahedral and tetrahegon geometries have been proposed for Fe(III)-, Co(II)-complexes and Zn(II)-complex, respectively. In vitro test of susceptibility of Fe(III)- and Zn(II)-complexes showed stronger activity than that of norfloxacin against G(-) E.Coli and Bacillus dysenteriae bacteria.

Intercellular adhesion molecule-2 (CD102) binds to the leukocyte integrin CD11b/CD18 through the A domain

The interactions between the leukocyte-specific beta 2-integrins cluster of differentiation (CD) Ag CD11/CD18 and their ligands, the intercellular adhesion molecules (ICAMs), play important roles in many adhesion-dependent leukocyte functions. ICAM-1 is known to be a ligand for both CD11a/CD18 and CD11b/CD18. ICAM-2, whose two extracellular Ig domains show the highest homology to the two NH2-terminal domains of ICAM-1, has been previously shown to be a ligand for CD11a/CD18. We recently found that a 22-amino acid CD11a/CD18-binding peptide, P1, derived from the first domain of ICAM-2, also binds to purified CD11b/CD18. In the present study, we demonstrate that the ICAM-2 protein interacts with CD11b/CD18, and the binding is through the CD11b A domain.

Intercellular adhesion molecule-2 (CD102) binds to the leukocyte integrin CD11b/CD18 through the A domain

The interactions between the leukocyte-specific beta 2-integrins cluster of differentiation (CD) Ag CD11/CD18 and their ligands, the intercellular adhesion molecules (ICAMs), play important roles in many adhesion-dependent leukocyte functions. ICAM-1 is known to be a ligand for both CD11a/CD18 and CD11b/CD18. ICAM-2, whose two extracellular Ig domains show the highest homology to the two NH2-terminal domains of ICAM-1, has been previously shown to be a ligand for CD11a/CD18. We recently found that a 22-amino acid CD11a/CD18-binding peptide, P1, derived from the first domain of ICAM-2, also binds to purified CD11b/CD18. In the present study, we demonstrate that the ICAM-2 protein interacts with CD11b/CD18, and the binding is through the CD11b A domain.

Controlling cancerous pain with analgesic powder for cancers

Analgesic powder for cancers, composed of more than 20 Chinese drugs, was applied externally to 91 patients with various kinds of cancers for management of cancerous pain. The results showed that it was remarkably effective in 42 cases, fairly effective in 22, effective in 22, and ineffective in 5, the total effective rate being 94.51%. Animal experiments indicated that the pain threshold was evidently higher in mice treated with this powder on the site of femoral artery of the hind limbs than that of the controls without application of this powder.

Nitric oxide production in experimental alcoholic liver disease in the rat: role in protection from injury

BACKGROUND & AIMS

Regulation of blood flow and oxygen supply are important pathogenetic factors in alcoholic liver disease. Because nitric oxide may have an important role, its effects on alcoholic liver injury were investigated.

METHODS

Rats were fed ethanol intragastrically with either saturated fat or corn oil. Spontaneous production of NO by liver nonparenchymal cells was compared in the two dietary groups. Two additional groups of rats fed corn oil and ethanol were treated with either an NO inhibitor (L-NAME) or supplemented with L-arginine. Liver pathology and plasma NO production were evaluated.

RESULTS

In the corn oil and ethanol group, a progressive decrease in liver nonparenchymal cell NO production and increased plasma NO levels were associated with liver injury. Reduced nicotinamide adenine dinucleotide phosphate diaphorase staining showed increased centrilobular staining of hepatocytes in the corn oil and ethanol group and L-NAME-treated group. Moreover, L-NAME increased the severity, whereas L-arginine supplementation completely prevented liver injury. In the saturated fat and ethanol group, in which there was no liver injury, the levels of NO2- in nonparenchymal supernatant were 5-10-fold higher than in the corn oil and ethanol group.

CONCLUSIONS

Decreased NO production by nonparenchymal cells may contribute to liver injury in ethanol-fed rats, and the compensatory increase in hepatocyte NO production may contribute to centrilobular liver injury.

Differential effects of in vivo ethanol on LPS-induced TNF and nitric oxide production in the lung

Alcohol (EtOH) has been shown to suppress lipopolysaccharide (LPS)-induced nitric oxide (NO) generation and tumor necrosis factor (TNF) production in the lung in vivo. We have previously reported that EtOH suppressed gene expression for inducible nitric oxide synthase (iNOS) with a subsequent decrease in release of reactive nitrogen intermediates by alveolar macrophages and recruited lung neutrophils. We hypothesized that a similar mechanism may be involved in EtOH-induced suppression of LPS-stimulated TNF production. In contrast to what we found with iNOS, EtOH had no effect on TNF mRNA in alveolar macrophages or recruited lung neutrophils. However, immunoreactive and bioactive TNF was reduced by 72%. EtOH treatment resulted in an increased level of the membrane-bound 26-kDa form of TNF, which suggested that proteolytic cleavage of this prohormone was affected by EtOH. Experiments with t-butyl alcohol, a tertiary alcohol that is not metabolized to acetaldehyde, yielded similar results. Thus EtOH appears to be the active substance in suppression of TNF in the lung in vivo. Pretreatment with intratracheal interferon-gamma 24 h before intratracheal LPS increased TNF bioactivity partly due to increased TNF mRNA and by increasing TNF processing, as evidenced by a decrease in the 26-kDa TNF prohormone and an increase in immunoreactive and bioactive TNF.

A peptide derived from the intercellular adhesion molecule-2 regulates the avidity of the leukocyte integrins CD11b/CD18 and CD11c/CD18

beta 2 integrin (CD11a,b,c/CD18)-mediated cell adhesion is required for many leukocyte functions. Under normal circumstances, the integrins are nonadhesive, and become adhesive for their cell surface ligands, the intercellular adhesion molecules (ICAMs), or soluble ligands such as fibrinogen and iC3b, when leukocytes are activated. Recently, we defined a peptide derived from ICAM-2, which specifically binds to purified CD11a/CD18. Furthermore, this peptide strongly induces T cell aggregation mainly mediated by CD11a/CD18-ICAM-1 interaction, and natural killer cell cytotoxicity. In the present study, we show that the same ICAM-2 peptide also avidly binds to purified CD11b/CD18, but not to CD11c/CD18. This binding can be blocked by the CD11b antibody OKM10. The peptide strongly stimulates CD11b/CD18-ICAM-1-mediated cell aggregations of the monocytic cell lines THP-1 and U937. The aggregations are energy and divalent cation-dependent. The ICAM-2 peptide also induces CD11b/CD18 and CD11c/CD18-mediated binding of THP-1 cells to fibrinogen and iC3b coated on plastic. These findings indicate that in addition to induction of CD11a/CD18-mediated cell adhesion, the ICAM-2 peptide may also serve as a "trigger" for high avidity ligand binding of other beta 2 integrins.

Rapid induction of mRNA for nitric oxide synthase II in rat alveolar macrophages by intratracheal administration of Mycobacterium tuberculosis and Mycobacterium avium

Mycobacterium avium complex (MAC) organisms are among the most common bacterial cause of disseminated infection in patients with acquired immune deficiency syndrome (AIDS). An increase in the incidence of virulent Mycobacterium tuberculosis (MTB) is also occurring throughout the world. In vitro data suggest that nitric oxide (NO) may be important in restricting the growth of MAC. However, the ability of MTB to stimulate NO production and the susceptibility of MTB to the bactericidal activity of NO produced by murine alveolar macrophages (AM) is controversial. This study tested the hypothesis that in vivo administration of heat-killed MAC (strain 100 and 101) and human virulent MTB (strain F1) to rats stimulated NO production by rat AM, ex vivo. We show that heat-killed MTB instilled into rat lungs rapidly induced mRNA for NO synthase (iNOS) II in AM obtained by bronchoalveolar lavage (BAL). In contrast, expression of AM iNOS mRNA was only found in 40% of the rats given MAC. Moreover, the change in iNOS mRNA in the AM obtained from rats given MTB and MAC correlated with the production of the reactive nitrogen intermediates (RNI) NO2- and NO3- in BAL fluid, lung homogenate, and the spontaneous generation of RNI by isolated AM ex vivo and occurred without measurable increases in BAL fluid tumor necrosis factor-alpha (TNF-alpha). L-NG-monomethylarginine (50 mg/kg, ip) given 30 min before MAC or MTB attenuated the increase in RNI in lung homogenates and BAL fluid. This is the first demonstration that in vivo exposure to MTB results in rapid upregulation of gene expression for iNOS which is associated with functional RNI production by rat AM. These results show that MTB human virulent strain 1 has the ability to rapidly upregulate iNOS mRNA in AM. If human AM generate NO from L-arginine by either iNOS or other NADPH oxidases then NO may play a role in the overall host-defense response of the lung to MAC and MTB.

Ethanol suppresses Mycobacteria tuberculosis-induced mRNA for nitric oxide synthase in alveolar macrophages, in vivo

Acute ingestion of alcohol [ethanol (ETOH)] adversely affects the immunocompetence of both naive individuals as well as chronic alcohol abusers. An increased incidence and severity of tuberculosis is found in chronic alcohol abusers. Nitric oxide (NO) produced by alveolar macrophages (AMs) may play a role in the in vitro killing of Mycobacterium avium and Mycobacterium tuberculosis (MTB). Moreover, tumor necrosis factor-alpha (TNF-alpha) is believed to be a primary cytokine mediator of NO production by AMs. Recent studies from our laboratory demonstrated that ETOH suppressed endotoxin-induced increases in both TNF-alpha and NO in AMs, in vivo. We tested the postulate that acute ingestion of ETOH can interfere with mycobacteria-induced upregulation of the NO system in AMs, in vivo. We show that heat-killed M. avium complex (MAC) and human virulent MTB instilled into rat lungs rapidly increased mRNA for inducible NO synthase II (iNOS) of AMs in fluid obtained by bronchoalveolar lavage (BAL fluid). This was associated with production of reactive nitrogen intermediates [(RNIs); NO2- and NO3-] in BAL fluid, lung homogenate, and AMs in the absence of a significant increase in BAL fluid TNF-alpha. A single dose of ETOH (5.5 g/kg, ip) administered 30 min before intratracheal administration of MAC or MTB attenuated both MAC and MTB-induced increases in RNI in BAL fluid, lung, and AMs, and the increase in mRNA for iNOS. Thus, mycobacteria upregulate iNOS mRNA and enhance RNI production by AMs without any increase in the production of TNF-alpha. Moreover, ETOH attenuates mycobacteria-induced upregulation of mRNA for iNOS and RNI production in the absence of ETOH-mediated suppression of TNF. Speculatively, ETOH-mediated inhibition of the AM NO system may offer an explanation for the increased severity of mycobacterial infections in alcoholics.

Hydroxocobalamin (vitamin B12a) prevents and reverses endotoxin-induced hypotension and mortality in rodents: role of nitric oxide

The cobalt atom of hydroxocobalamin (OHC) binds cyanide and nitric oxide (NO) and OHC attenuates vascular responses to NO in vitro. NO mediates the hypotension of endotoxemia. Thus, we tested the postulate that OHC may attenuate the acute phase hypotension and toxicity associated with administration of Escherichia coli endotoxin (LPS). Rats were given OHC (20 mg/kg i.v.) or phosphate-buffered saline (PBS, 1 ml/kg i.v.) 30 min before or 15 min after giving LPS (0.8 mg/kg i.v.). Administration of OHC to PBS-treated control rats did not affect mean arterial pressure (MAP), heart rate or the plasma or urine content of the reactive nitrogen intermediates nitrate and nitrite (RNI). LPS decreased MAP by 50 mm Hg in PBS-treated rats and increased the plasma and urinary content of RNI. Administration of OHC to PBS-treated rats did not affect MAP or RNI. However, treatment with OHC before or after giving LPS attenuated LPS-induced hypotension and increases in plasma RNI and enhanced LPS-induced urinary excretion of RNI. OHC (20 mg/kg i.p.) or cyanocobalamin (10 mg/kg i.p.) given to Swiss-Webster mice 30 min before giving LPS (16 mg/kg i.p.) decreased the 24-hr mortality of LPS from 80 to 50% and the 36- and 96-hr mortality from 100 to 60% (OHC) or 70% (cyanocobalamin). Urine obtained from conscious rats given LPS (5 mg/kg i.p.) and OHC (20 mg/kg i.p.) exhibited a UV-visible absorbance spectrum with absorbance peaks characteristic of that formed after coincubation of NO and OHC.(ABSTRACT TRUNCATED AT 250 WORDS)

Bonding of composite resin to contaminated human enamel and dentin

PURPOSE

The purpose of this in vitro study was to evaluate the bond strengths of a bonding agent and composite resin system to human enamel and dentin treated with five contaminants (saliva, plasma, zinc oxide-eugenol cement, noneugenol zinc oxide cement, and handpiece lubricant) using air, moisture, and water as controls.

MATERIALS AND METHODS

A commercial bonding agent (Gluma 2000; Bayer AG, Dormagen, Germany) and its composite (Pekafill; Bayer AG) were applied to tooth structure under two conditions (contaminated and re-etched). Samples were debonded in tension after 24 hours using an inverted, truncated cone bond test.

RESULTS

Among the controls, the highest bond strengths were obtained to enamel (20 MPa) and dentin (12 MPa) with air drying. Contaminants lowered the bond strength by 20% to 100%. Re-etching without additional mechanical preparation resulted in bond strengths similar to the air control.

CONCLUSIONS

Bond strength of Gluma 2000/Pekafill to tooth structure is sensitive to common forms of contamination but can be improved by re-etching after contamination occurs.

Two closely linked but separable promoters for human neuronal nitric oxide synthase gene transcription

In this report we demonstrate that the human cerebellum contains neuronal nitric oxide synthase (nNOS) mRNAs with two distinct 5'-untranslated regions that are encoded through use of closely linked but separate promoters. nNOS cDNA clones were shown to contain different 5' terminal exons spliced to a common exon 2. Genomic cloning and sequence analysis demonstrate that the unique exons are positioned within 300 bp of each other but separated from exon 2 by an intron that is at least 20 kb in length. A CpG island engulfs the downstream 5'-terminal exon. In contrast, most of the upstream exon resides outside of this CpG island. Interestingly, the upstream exon includes a GT dinucleotide repeat. A fusion gene with a 414-bp nNOS genomic fragment that includes a portion of the upstream 5'-terminal exon and its immediate 5'-flanking DNA is expressed in transfected HeLa cells. Also expressed is a fusion gene that contains the luciferase reporter under transcriptional control by a 308-bp genomic fragment that includes the region separating both 5'-terminal exons. These results indicate that expression of these exons is subject to transcriptional control by separate promoters. However, the proximity of these promoters raise the possibility that complex interactions may be involved in regulating nNOS gene expression at these sites.

High-performance liquid chromatography of amino acids, peptides and proteins. CXXXVIII. Adsorption of horse heart cytochrome c onto a tentacle-type cation exchanger

Determination of the change in the Gibb's free energy from the adsorption isotherm associated with the interaction between a biomolecule and an ion-exchange resin is often achieved by assuming that a Langmuirean model prevails. However, the adsorption of horse heart cytochrome c onto the tentacle-type cation exchanger LiChrospher 1000 SO3- at pH 4.00 showed an isotherm of rectangular form. In this case the Langmuirean model is not applicable. In this paper, we propose an alternative way to deal with this situation, whereby the adsorption capacity of the adsorbent with a defined protein sample is studied as a function of displacing-ion concentration. The experimental conditions over defined ranges are then selected in order to relate this function to the change in the Gibb's free energy for the interaction between the protein and the ion exchanger. Additional comments about the general utility of the on-line adsorption vessel system employed to determine the adsorption isotherms are also made.

Independent suppression of nitric oxide and TNF alpha in the lung of conscious rats by ethanol

Tumor necrosis factor-alpha (TNF alpha) and nitric oxide (NO) mediate in part the microbicidal response of murine and rodent alveolar macrophages (AM) and recruited neutrophils (PMN) to airborne infections. Ethanol (ETOH) suppresses intrapulmonary TNF alpha and NO release and impairs pulmonary host defense mechanisms. We tested the concept that ETOH down-regulates NO by inhibiting production of TNF alpha. Male rats were given intratracheal (i.t.) saline (PBS), a polyclonal anti-TNF alpha antibody (TNFab) or nonimmune IgG (22 mg/kg, i.m.) 2 h before giving i.t. Escherichia coli endotoxin (LPS) to normal rats or rats pretreated with ETOM (5.5 g/kg, i.p.) 30 min before experimentation. AM and PMN were obtained from the bronchoalveolar lavage fluid (BAL) fluid of rats killed 2 and 4 h after administration of LPS. mRNA for inducible NO synthase (iNOS) and TNF alpha were measured in AM and PMN with competitor equalized RT-PCR techniques. The BAL fluid, AM, and PMN were assayed for TNF alpha and NO2-, and NO3- (RNI) with the L929 bioassay and chemiluminescence, respectively. TNFab abolished LPS-induced increases in TNF alpha but did not suppress the NO content of the BAL fluid or gene expression for iNOS by AM or PMN. ETOH suppressed LPS-induced increases in mRNA for iNOS, production of RNI, and BAL fluid TNF alpha but did not affect LPS-induced increases in mRNA for TNF alpha. ETOH-induced attenuation of LPS-induced up-regulation of the iNOS system did not differ in rats pretreated with TNFab or IgG. Thus, ETOH down-regulates iNOS gene expression and RNI production independent of its effects on TNF alpha. Acute ETOH administration suppresses iNOS at the level of transcription and TNF alpha at the level of translation or release of the peptide.

Bending of blood vessel wall: stress-strain laws of the intima-media and adventitial layers

In order to determine the stress-strain relationship of the inner (intima and media) and outer (adventitia) layers of blood vessels in the neighborhood of the zero-stress state, bending experiments were performed on aortic strips of rats. In the experiments, one end of a strip was clamped, and a force was applied on the other end. The deflection curves of the strips were measured. By regarding the aortic strip as a curved beam, the classical beam theory was employed to analyze the strain distribution from the experimental data. A computer program dealing with nonlinear equations and nonlinear least squares optimization was developed. Strains were referred to the zero-stress state. The load-deflection relationship was then used to determine the stress-strain relationship. Certain forms of the stress-strain laws were assumed. The linear laws fit the experimental data accurately, probably because the strains during bending are quite small, although the rotations are large. The Young's modulus of the inner layer, which consists of endothelial and smooth muscle cells and elastic lamina, was found to be three to four times larger than that of the outer layer which consists of collagen with a small amount of fibroblasts and elastin. The residual stresses and strains at the no-load state were calculated from the deduced stress-strain relationship. It is shown that large errors (up to 50 percent) in the values of the residual strains will occur if the wall material was treated as homogeneous, i.e., if the layered constitution was ignored.

In vivo administration of endotoxin and tumor necrosis factor-alpha produce different effects on constitutive and inducible nitric oxide synthase activity in rat neutrophils and aorta ex vivo

Tumor necrosis factor-alpha (TNF-alpha) inhibits release of nitric oxide (NO) in vitro by stimulating the degradation of constitutive NO synthase (cNOS III) mRNA. However, TNF-alpha is believed to be the cytokine mediator of the hypotension and upregulation of inducible NO synthase (iNOS II) produced by gram-negative bacterial endotoxin (LPS). Some in vivo effects of TNF-alpha are opposite to those which occur in vitro. This study tested the hypothesis that in vivo administration of exogenous TNF-alpha and endogenously released TNF-alpha induce iNOS II activity and inhibit cNOS III activity, and thereby mediate the acute phase effects of LPS on blood pressure and the NO system in the rat. We show that LPS produces acute phase hypotension in ketamine anesthetized rats. The hypotension was associated with elevation of biologically active TNF-alpha in plasma, increased production of RNI (NO2- and NO3- anion) in rat neutrophils (PMN) and suppression of RNI production by A23187 (1 microM) stimulated thoracic aorta (RTA) ex vivo. TNA-alpha (10(6) U/ml, iv) did not produce acute phase hypotension but initially raised arterial blood pressure and heart rate (HR), did not increase RNI production by PMN, and inhibited RNI production by A23187 stimulated RTA ex vivo. Pretreatment of rats with the immunex monomeric soluble P75 receptor binding protein for TNF-alpha (TNFsr, 0.5 mg/kg, iv) 15 min prior to LPS administration decreased circulating TNF-alpha from 92,137 +/- 12,456 U/ml to undetectable levels as determined by the L929 bioassay. However, LPS-induced increases in RNI in PMN was enhanced and LPS-induced decreases in RNI production by RTA was inhibited by TNFsr. Thus, in vivo administration of TNF-alpha does not mimic the hemodynamic and NO-inducing effects of LPS. However, TNF-alpha mediates in part LPS-induced inhibition of RNI production by RTA. Thus, endogenous TNF-alpha is not required for LPS-induced acute phase hypotension or iNOS II activity. The importance of TNF-alpha in sepsis resides in systems other than iNOSII and blood pressure.

V-J junctional sequences of T cell receptor gamma gene in acute lymphocytic leukemia

T cell receptor TCR gamma gene rearrangement in a series of acute lymphocytic leukemia (ALL) patients was studied using PCR technique. 18 V-J junctional sequences (designated by N sequence) of TCR gamma gene were amplified with the V gamma and J gamma primers, using an unsymmetrical PCR and analysed by direct sequencing, demonstrating that in Chinese ALLs, the N sequences of TCR gamma gene are indeed clone-specific. Based on the known N sequences, several oligo-nucleotides were synthesized as probes, which were specific for the leukemic clone, and were used to detect the minimal residual disease (MRD) in 4 ALL cases. The sensitivity of this method was 0.1%-0.01%.

Ethanol suppresses LPS-induced mRNA for nitric oxide synthase II in alveolar macrophages in vivo and in vitro

Alcohol abuse increases the incidence and severity of opportunistic lung infections and pneumonias. Inducible nitric oxide (NO) synthase (iNOS II) and NO may be a pivotal system in the intracellular bactericidal activity of macrophages. We tested the hypothesis that acute administration of ethanol (ETOH) suppressed Escherichia coli endotoxin lipopolysaccharide (LPS) mediated upregulation of the iNOS II system in the lung of the rat, in vivo. We also tested the effect of ETOH on alveolar macrophage (AM) production of free NO using microelectrodes. Male Sprague-Dawley rats were given ETOH (5.5 g/kg, IP) 30 min. before giving intratracheal sterile phosphate buffered saline solution (PBS, 0.5 ml) or LPS (1 mg/kg in a total volume of 0.5 ml PBS). The isolated lungs were subjected to bronchoalveolar lavage (BAL) 3.5 hr. later. Aliquots of the BAL fluid were assayed for tumor necrosis factor alpha TNF alpha and reactive nitrogen intermediates (nitrate and nitrite) (RNI) with chemiluminescence. Aliquots of AM were incubated 1 hr ex vivo for spontaneous production of RNI or frozen and assayed for iNOS II mRNA with competitor exchange reverse transcriptase polymerase chain reaction (cERT-PCR). The lung was homogenized and assayed for RNI. LPS increased BAL fluid TNF alpha and RNI, lung RNI, and the spontaneous production of RNI by AM, ex vivo. These effects were inhibited by in vivo administration of inhibitors of iNOS II. LPS increased iNOS mRNA in AM. This was unaffected by iNOS inhibitors. ETOH suppressed LPS-induced BAL fluid TNF, iNOS mRNA and RNI production by AM and the lung.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of chelating agents on tissue distribution and excretion of nickel in mice

N-Benzyl-D-glucaminedithiocarbamate (BGD), diethyldithiocarbamate (DDTC), di-hydroxyethyldithiocarbamate (DHED), trans-1,2-cyclohexanediamine N,N,N',N'-tetra-acetic acid (CDTA), and 2,3-dimercaptosuccinic acid (DMSA) were studied for their relative efficacies in the distribution and excretion of nickel in mice exposed to nickel. Mice were injected intraperitoneally with NiCl2 (5mgNi/kg) and 30 min or 24 hr later, they were injected intraperitoneally with chelating agents (400 mumol/kg). At 30 min after treatment with nickel, these chelating agents all significantly enhanced the fecal excretion of nickel, and DMSA significantly increased the urinary excretion of the metal. At 24 hr after nickel treatment, BGD, DDTC, and DHED significantly increased the fecal excretion of nickel and BGD was the most effective on the fecal excretion of nickel. CDTA and DMSA significantly enhanced the urinary excretion of the metal. At 30 min after nickel treatment, chelating agents other than CDTA effectively depressed nickel concentration in the kidney, lung, and testes. BGD, CDTA, and DMSA significantly reduced the nickel concentration in the liver. However, DDTC and DHED caused the redistribution of nickel to the brain. At 24 hr after nickel treatment, these chelating agents were effective in mobilizing nickel from the kidney, and chelating agents other than DHED were effective in mobilizing nickel from the liver, lung, and testes. These results indicate that the injection of BGD or DMSA at both 30 min and 24 hr after treatment with nickel can remove nickel from the body without redistribution of nickel to other tissues, such as brain, more effectively than DDTC, DHED, and CDTA. Furthermore, the pattern of excretion of nickel after treatment with the chelating agents was related to the partition coefficients of the nickel-chelating agent complexes.

[The effect of Sindbis virus multiplication on gene expression of host cells]

Sindbis virus (SBV) infection mediated a rapid shutoff of host cellular gene expression (mRNA synthesis and protein synthesis); however the synthesis of cellular rRNA remained at the same level as the uninfected cells. Meanwhile a cellular protein P105 was shown to be enriched in the nuclear matrix. Actionmycin D treatment after virus infection resulted in an apparent reduce in the production of viral structural proteins and infectious virions. The results presented here not only demonstrated the complexity of SBV-mediated regulation of host gene expression, but also suggested SBV nonstructural protein nsP2 and capsid protein C were possibly involved in this process.

Selective pulmonary and venous smooth muscle relaxation by furosemide: a comparison with morphine

Furosemide and morphine reduce pulmonary edema associated with congestive heart failure. It is uncertain whether furosemide or morphine are direct-acting relaxants of arterial and venous smooth muscle. The authors compared the effect of furosemide and morphine on isolated rings of canine pulmonary artery (PA) and vein (PV) and mesenteric, splenic and anterior tibial arteries and their corresponding veins precontracted with norepinephrine or (15S)-hydroxy-11 alpha, 9 alpha-(epoxymethano)prosta-5Z,13E-dienoic acid. Furosemide (10-300 microM) selectively relaxed veins by an endothelium-independent mechanism, with its greatest efficacy on the PV. Morphine (10-1000 microM) relaxed both arteries and veins. The mechanism of relaxation by furosemide and morphine was examined in the PV and PA. Morphine-induced relaxation of the PV and PA was dependent on prostanoid release from endothelium and smooth muscle because it was attenuated in endothelium-rubbed and ibuprofen-treated PV and PA but not in blood vessels treated with inhibitors of nitric oxide system/cyclic GMP system (I-NG-nitroarginine and methylene blue). Furosemide-mediated relaxation of the PV was refractory to each of these interventions. Similarly, furosemide- and morphine-induced relaxation of the PV were unaffected by 4-aminopyridine, tetraethylammonium, glibenclamide, dendrodotoxin and apamin and, thereby, were independent of an action on K+ channels. Reduction of extracellular K+ or Cl- attenuated furosemide-mediated relaxation of, and inhibition of 86Rb+ uptake by, PV even in the presence of ouabain. It was concluded that furosemide relaxes veins by an effect on Na+/K+/Cl- cotransport or chloride-mediated refilling of intracellular calcium stores.

Golgi coatomer binds, and forms K(+)-selective channels gated by, inositol polyphosphates

Coatomer is a distinct type of coat protein complex involved in the formation of specific Golgi intercisternal transport vesicles. Direct binding studies using purified coatomer isolated from bovine liver cytosol show that coatomer specifically binds both inositol 1,3,4,5-tetrakisphosphate ((1,3,4,5)IP4) and inositol hexakisphosphate (IP6) with subnanomolar affinities (0.1 and 0.2 nM, respectively). Diphosphoinositol pentakisphosphate (PP-IP5) is an efficient competitor for both (1,3,4,5)IP4 and IP6 binding to coatomer. Inositol 1,3,4,5,6-pentakisphosphate ((1,3,4,5,6)IP5) is a poor inhibitor of IP6 binding, whereas little or no competition is detected with inositol 1,4,5-trisphosphate ((1,4,5)I-P3). Coatomer displays ion channel activity when reconstituted into planar bilayers which is preferentially permeable to K+. Permeability ratios of the channel are PK+/PCl- approximately 8.0 and PK+/PNa+ approximately 7.1, indicating a cation-selective channel with selectivity of K+ over Na+. In symmetrical 500 mM KCl, the smallest observable unitary channel conductance is 8.3 picosiemens. The coatomer channel activity is normally active with long open times (0.1 to several seconds) and is selectively blocked by 10 microM (1,3,4,5)IP4, 1 microM IP6, and 0.27 microM PP-IP5; even lower concentrations are sufficient to induce channel flicker. The channel activity is not affected by (1,4,5)IP3, or (1,3,4,5,6)IP5. Thus, the channel activity of coatomer is modulated by the inositol polyphosphates which exhibit tight binding to the complex.

The ability of transforming growth factor-beta 1 to preferentially inhibit the induction of cytotoxicity in human T cells is determined by the nature of the activating signals

TGF-beta is held to be a general inhibitor of the immune system, able to prevent the development of certain differentiated functions, such as the induction of LAK activity by IL-2. In the present study, the potential of TGF-beta 1 to inhibit anti-tumour responses was assessed by determining its relative effect on the proliferation and cytotoxicity of human T-cells, following activation by anti-CD3, anti-CD3 plus anti-CD28 or anti-CD3 plus IL-2. The results demonstrated that TGF-beta 1 inhibits the induction of cytotoxicity in human T-cells stimulated via CD3 or CD3 and CD28 (P < 0.01), without significantly altering their proliferative responses. The cytotoxic response following costimulation with IL-2 was hardly altered, while costimulation via CD28 was susceptible to suppression, suggesting that TGF-beta 1 action is affected by the nature of the costimulatory signals.

Isolation and characterization of a novel inositol hexakisphosphate binding protein from mammalian cell cytosol

Inositol hexakisphosphate (IP6) is present in most mammalian cells, although its intracellular function is as yet undefined. We find that the total protein fraction from bovine brain cytosol contains a significant level of specific binding for IP6 precipitable with 40% saturated ammonium sulfate. A protein complex has been isolated from this fraction that specifically binds IP6 and is purified about 500-fold over the cytosol. The IP6 binding protein (IP6BP) chromatographs as a single peak of binding activity on a gel exclusion column, with a Stokes radius equivalent to 266 +/- 14 kDa. The IP6BP is a heterooligomeric complex composed of a number of subunits with molecular weights varying from 23,000 to 60,000, as determined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS-PAGE). Scatchard analyses of IP6 binding of both the crude ammonium sulfate fraction and the purified complex show the presence of a similar high-affinity binding site (Kd approximately 6.0 nM). Bmax for the purified fraction is 1.8 nmol of IP6/mg of protein or 0.48 mol of IP6 bound/mol of complex. Other inositol polyphosphates, such as inositol 1,3,4,5,6-pentakisphosphate, inositol 1,3,4,5-tetrakisphosphate, and inositol 1,4,5-trisphosphate, are poor competitors for IP6 binding to the purified complex. The purification scheme, when applied to a rat liver cytosol fraction, yields a similar IP6BP. This complex has an apparent size of 512,000 using gel exclusion chromatography and contains an additional protein band with M(r) = 97,000 by SDS-PAGE.(ABSTRACT TRUNCATED AT 250 WORDS)

Secular trends in cerebrovascular mortality

Since 1950 a marked decrease in cerebrovascular mortality has occurred in most Western countries. To evaluate whether changes in the pharmacological treatment of hypertension, introduced during the period observed (1950-87), have influenced this downward trend the linear time-trends over the period considered were calculated. Mass treatment of hypertension at the population level started in the early 1970s. Before this period a marked decrease in cerebrovascular mortality had already occurred. Moreover, the linear time trends were highly significant over the whole period with several correlation coefficients of > 0.98. The decrease in cerebrovascular mortality can best be explained by a decreased salt and saturated fat intake in the populations considered. In several Eastern European countries cerebrovascular mortality has increased. This runs parallel with an increase in all-cause mortality and an increase in ischaemic heart disease mortality and can be explained by the high saturated fat intake of these populations. The data show that important changes in cerebrovascular mortality are also occurring in the older age groups, e.g. 70-74 and 80-84 years. Epidemiological data point towards nutrition as playing an important role in the evolution of cerebrovascular mortality over the period considered.

Phenol red is a thromboxane A2/prostaglandin H2 receptor antagonist in canine lingual arteries and human platelets

Phenol red (PR) is used as a pH indicator in cell culture medium. We found that cell culture medium containing PR relaxed canine lingual arteries (LA) contracted by the thromboxane A2/prostaglandin endoperoxide (TPE) receptor agonist (15S)-hydroxy-11-alpha-9-alpha- (epoxymethano)prosta-5Z,13E-dienoic acid (U46619). We tested the effect of PR and the TPE receptor antagonist ONO-3708 on U46619, prostaglandin F2 alpha (PGF2 alpha), phenylephrine (PE) and potassium chloride (KCl)-induced contraction of the LA and on human platelet aggregation to U46619, ADP, arachidonic acid (AA), A23187 and thrombin. U46619, PGF2 alpha, KCl and PE produced equal tension development of the LA. PR relaxed the LA contracted with U46619 and PGF2 alpha with IC50 concentrations of 18.3 +/- 10 and 37.3 +/- 8.8 microM, respectively. ONO-3708 inhibited the contractions to U46619 and PGF2 alpha with IC50 of 9.4 +/- 2.2 and 12.2 +/- 2.2 nM, respectively. However, PR (300 microM) and ONO-3708 (300 nM) did not affect contraction of the LA to KCl or PE. PR inhibited human platelet aggregation, in vitro, to AA and U46619 and second wave aggregation to ADP but did not affect thrombin or first wave ADP-mediated platelet aggregation. PR inhibited U46619 and AA-induced changes in cyclic AMP and Fura-2 calcium transients in platelets and LA. However, PR did not affect the activation of cyclic AMP or intracellular calcium ion in platelets or calcium influx and the release of intracellular calcium ion in canine LA produced by ryanodine, KCl and PE. The concentration of PR in many culture media is between 40 and 70 microM. The data support the conclusion that PR, in concentrations used as a pH indicator, is a selective antagonist of TPE receptors.

Rapid induction of messenger RNA for nitric oxide synthase II in rat neutrophils in vivo by endotoxin and its suppression by prednisolone

Nitric oxide is believed to participate in nonspecific cellular immunity. Gram negative bacterial endotoxins increase the production of reactive nitrogen intermediates (RNI) in phagocytic cells by inducing the enzyme nitric oxide synthase II (NOS II). Anti-inflammatory glucocorticoids attenuate endotoxin-induced increases in RNI. This study evaluated the effect of in vivo administration of prednisolone on Escherichia coli lipopolysaccharide endotoxin (LPS)-induced increases in plasma RNI and neutrophil mRNA for NOS II and production of RNI in the rat. We show that LPS rapidly induces mRNA for NOS II and production of RNI (NO2- and NO3- anion) in rat neutrophils within 2 hr after in vivo administration of a sublethal dose of 0.5 mg/kg, i.v. A pharmacologic dose of prednisolone (50 micrograms/kg, im) given 15 min before LPS-attenuated production of NO2- and NO3- by neutrophils and suppressed LPS-stimulated mRNA for NOS II. 3-Amino, 1,2,4-triazine inhibited NO2- and NO3- production without affecting gene expression for NOS II. These data demonstrate that LPS rapidly induces functional gene expression for NOS II and prednisolone prevents induction of NOS II activity by inhibiting transcription of its mRNA.

Escherichia coli-induced inhibition of endothelium-dependent relaxation and gene expression and release of nitric oxide is attenuated by chronic alcohol ingestion

We examined the effect of chronic administration of ETOH on Escherichia coli-mediated suppression of relaxation and nitric oxide (NO) production by the rat thoracic aorta (RTA) and gene expression for constitutive NO synthase (cNOS) by the adrenal gland. Chronic alcoholic rats ("alcoholic") were fed a diet containing ETOH as 36% of the caloric intake for 8-10 weeks. Nonalcoholic control rats ("control") were fed an isocaloric equivalent diet containing 36% dextrin. Alcoholic rats were given an injection of approximately approximately 10(10) live E. coli through a dorsal SC catheter 24 and 19 h before experimentation ("alcoholic-septic"), and control rats were treated in an identical manner ("septic"). The next day the rats were anesthetized with ketamine-xylazine (0.1 ml/100 g rat) and rings of RTA were mounted in muscle chambers for isometric recording of force development. Rings of RTA were precontracted with an EC50 concentration of phenylephrine, and relaxation to acetylcholine (ACh), A23187, and nitroglycerin were obtained. A23187- and ACh-induced relaxation was attenuated in RTA obtained from septic rats, whereas the relaxation to nitroglycerin was slightly enhanced. Chronic administration of ETOH attenuated the effects of E. coli on endothelium-dependent relaxation in alcoholic-septic rats. NO was measured with ozone chemiluminescence. Basal and stimulated NO production was attenuated in RTA obtained from septic rats and unaffected in RTA obtained from alcoholic or alcoholic-septic rats. cNOS was unmeasurable in adrenals from septic rats. ETOH increased mRNA for cNOS, an effect amplified in alcoholic-septic rats. Thus, E. coli inhibits endothelium-dependent relaxation and NO production, and ETOH attenuates these effects of E. coli on the endothelium-NO system, possibly by upregulating gene expression for cNOS.

Alcohol administration attenuates LPS-induced expression of inducible nitric oxide synthase in Kupffer and hepatic endothelial cells

This study investigates the effects of in vivo ethanol (primed infusion, causing 170-190 mg% plasma alcohol for 12 hours) and/or LPS (12 hours after injection of E. coli LPS 1 mg/kg bw.) on the mRNA expression of inducible nitric oxide synthase (NOS II) in hepatic cells measured by competitive PCR technique, and on hepatic release of reactive nitrogen intermediates (RNI, NO2- + NO3-). Perfused livers from alcohol- or saline-infused animals did not release measurable amounts of RNI. Under these conditions small amounts of NOS II mRNA were expressed in Kupffer and endothelial cells, while it was not detectable in parenchymal cells. LPS treatment along with markedly elevating hepatic RNI release increased NOS II mRNA levels by 35- and 200-fold, in endothelial and Kupffer cells, respectively. LPS injection and alcohol infusion to the same animal decreased hepatic RNI release by about 70% and almost completely inhibited the LPS-induced, elevated NOS II mRNA in Kupffer or endothelial cells. No similar changes were observed in the parenchymal cells. These data suggest that the primary target of in vivo LPS in upregulating hepatic NO release are the nonparenchymal cells. Furthermore, alcohol inhibits the LPS-induced response which may influence immune-related hepatic function.

Molecular characterization of a multi-promoter gene encoding a chicken filamin protein

We report the cloning and sequencing of cDNA encoding a chicken filamin protein. The 2,567 amino acid protein contains an NH2-terminal 267 amino acid actin-binding domain followed by a series of 24 repeating units that are each approximately 95 amino acids in length. The overall primary structure of filamin closely resembles that of human actin-binding protein (ABP). However, filamin lacks a 24-amino-acid insertion prior to repeat 16 that is contained within ABP. This region of human ABP is a site of calpain cleavage and is thought to confer flexibility on the molecule. Hence, it is possible that the properties of actin gels formed with either human ABP or filamin reflect the presence or absence of this insertion. Filamin is encoded within a multi-promoter transcription unit. A downstream filamin promoter (Fil1) resembles those of certain housekeeping genes and has a putative binding site for the transcription factor E2F. Thus, transcription from this promoter may be linked to the cell cycle. A second filamin promoter (Fil2) is located at least 8 kilobases upstream from the Fil1 promoter. This structural arrangement suggests that regulation of filamin gene expression is likely to be complex.

[A cephalometric study on determining the orientation of occlusal plane]

A study of the parallel relationship between the occlusal plane and the line connecting nasal alar and tragus was made in 90 dentulous cases by using cephalometry. The results show that the line connecting the inferior point of nasal alar and the mid-point of tragus runs much more parallel with the occlusal plane. The regression equation reveals a "line of closest fitting". It was used in the prosthetic treatment for 50 edentulous patients with good clinical results. The line connecting the inferior point of nasal alar and the mid-point of tragus therefore represents a proper reference plane for determining occlusal plane and hence should be still a valuable index in clinical dentistry.

Tumor necrosis factor inhibits stimulated but not basal release of nitric oxide

Tumor necrosis factor alpha (TNF alpha) increases nitric oxide (NO) synthase in vascular endothelium, but it inhibits endothelium-dependent relaxation (EDR) of vascular smooth muscle. We tested whether TNF alpha inhibits the response to, or release of, NO in bovine pulmonary artery (BPA) using the technique of perfusion-superfusion bioassay and ozone chemiluminescence. Effluent from the perfused BPA with endothelium (donor)-relaxed endothelium-rubbed bovine coronary artery (BCA) (detector). Moreover, effluent from the donor stimulated with acetylcholine (ACh) or bradykinin (BK) (0.001 to 100 nmol) relaxed the detector. Direct application of these agonists to the detector failed to produce relaxation. Basal and agonist-stimulated effluent from the donor treated with L-NG-monomethylarginine (LNMMA) (100 microM) suppressed effluent-mediated relaxation of the detector. ACh and BK released LNMMA-inhibitable nitrite and nitrate from the BPA. Thus, the effluent contained NO. Exposure of the donor to TNF alpha (1.25 micrograms/ml) for 60 min did not affect basal release of NO, but it attenuated bioassayable and chemiluminescence-detectable NO release by ACh and BK. The inhibition of NO release was directly related to the magnitude of inhibition of EDR by ACh and BK. Thus, TNF alpha selectively inhibits receptor-mediated release of NO without affecting basal release of NO. This effect differs from that of L-arginine-based inhibitors of NO and represents a unique physiologic mechanism of regulation of NO in the endothelium.

Tumor necrosis factor alpha inhibits contractions to sympathetic nerve stimulation by a nitric oxide-dependent mechanism

Gram-negative sepsis and administration of tumor necrosis factor alpha (TNF alpha) are associated with hypotension and peripheral neuropathies suggestive of impaired sympathetic neurotransmission. We examined the effect of TNF alpha on the responses of the bovine pulmonary artery (BPA) to transmural sympathetic nerve stimulation (SNS). BPA contracted to SNS (0.5-32 Hz, 5-10 V, 2-msec duration, 2-msec delay) in a frequency-dependent manner. The contractions of the BPA to SNS were mediated by norepinephrine and activation of postsynaptic alpha 1-adrenoceptors, since they were attenuated by prazosin. Maximum contraction of the BPA to SNS was significantly enhanced (148 +/- 37% increase, n = 6) after inhibition of nitric oxide synthase with L-NG-monomethylarginine (LNMMA, 500 microM), an effect abrogated by L-arginine (1 mM). TNF alpha (0.0042, 0.042, and 0.42 micrograms/ml) selectively inhibited contractions of the BPA to SNS without affecting the contraction of the BPA to exogenous norepinephrine. In BPA incubated with LNMMA (5-500 microM), TNF alpha facilitated rather than inhibited SNS. TNF alpha increased the formation of amperiometrically measured free nitric oxide in bovine adrenal chromaffin cells in primary culture. The data show that in the absence of LNMMA, TNF alpha releases free nitric oxide from a sympathetic neuron and selectively inhibits the contractions of the BPA to SNS. In BPA in which nitric oxide synthase I is inhibited by LNMMA, TNF alpha amplifies the contractions to SNS, even in the absence of endothelium. Thus, TNF alpha can modify vascular smooth muscle tone by affecting SNS. TNF alpha inhibits SNS at the level of the neuron by a mechanism involving the L-arginine-nitric oxide pathway. TNF alpha-induced suppression of SNS and neurotransmission may contribute to the hypotension and peripheral neuropathy of sepsis.

In vitro bond strength of two adhesives to enamel and dentin under normal and contaminated conditions

In vitro bond strengths of human enamel and dentin treated with five contaminants were measured with air, water and damp conditions as controls. Two commercial bonding agents (a lower-viscosity, solvent-containing type, AB, and a higher-viscosity, hydrophilic monomer type, SB) and their composites were applied to tooth structure under two conditions (contaminated and re-etched). Samples were debonded in tension after 24 h using an inverted, truncated cone test. Among the controls, the highest bond strengths were obtained with damp conditions for AB (24 MPa) and damp conditions or air for SB (22 MPa) with small differences between enamel and dentin. Most contaminants lowered the bond strength. Re-etching without additional mechanical preparation resulted in bond strengths similar to controls. Bond strengths to tooth structure with the bonding agents tested may be less sensitive to common forms of contamination than typically assumed.