Biomedical subjects

S Tan

Publications and source records attributed to S Tan.

At least 19 recordsLinked to original sources

PubMed2000

Crystallization of the yeast MATalpha2/MCM1/DNA ternary complex: general methods and principles for protein/DNA cocrystallization.

We describe our efforts to crystallize binary MCM1/DNA and ternary MATalpha2/MCM1/DNA complexes, including the unsuccessful attempts to crystallize MCM1/DNA complexes and the successful design of DNA crystal packing that resulted in high-resolution crystals of the MATalpha2/MCM1/DNA complex. We detail general procedures useful for preparing protein/DNA cocrystals, including improved methods for producing and purifying DNA-binding proteins and DNA fragments, for purifying protein/DNA complexes, and for controlling pH conditions during crystallization. We also describe the rational design of DNA for protein/DNA cocrystallization attempts, based on our analysis of how straight and bent DNA with single base-pair overhangs can pack end-to-end in a crystal.

Base Pairing↗

PubMed2000

The effect of polishing systems on microleakage of tooth coloured restoratives: Part 1. Conventional and resin-modified glass-ionomer cements.

The purpose of this in vitro study was to investigate the effect of polishing systems on the microleakage of conventional and resin-modified glass-ionomer cements. Class V cavities were prepared at the cemento-enamel junction of 80 freshly extracted posterior teeth. The prepared teeth were randomly divided into two groups and restored with conventional or resin-modified glass-ionomer cements. The restored teeth were stored in distilled water at 37 degrees C for 1 week after removal of excess restorative with diamond finishing burs. The restored teeth were then divided into four groups of 10 and finished and polished using the following systems: Two Striper MFS; Sof-Lex XT; Enhance Composite Finishing and Polishing System; Shofu Composite Finishing Kit. The finished restorations were subjected to dye penetration testing. Results showed that the microleakage at dentin margins of conventional glass-ionomer cements and enamel margins of resin-modified glass-ionomer cements are significantly affected by the different polishing systems.

Analysis of Variance↗

PubMed2000

Syncollin is differentially expressed in rat proximal small intestine and regulated by feeding behavior.

Gradients of gene expression are maintained along the proximal-distal axis of the mammalian small intestine despite a continuously regenerating epithelium. To study the molecular mechanisms responsible for this phenomenon, we utilized a subtractive hybridization strategy to isolate genes differentially expressed in the duodenum but not ileum. We isolated and sequenced 15 clones. The clones were fragments of genes encoding lipases, proteases, and an esterase. A novel clone was characterized and subsequently shown to encode syncollin, a secretory granule protein that binds to syntaxin in a calcium-sensitive manner. RT-PCR and S1 nuclease protection assay were used to clarify the 5'-end of syncollin. Syncollin was expressed in the rat pancreas, spleen, duodenum, and colon. In situ hybridization localized syncollin expression in the pancreas to acinar cells and in the duodenum to villus epithelial cells.

Amino Acid Sequence↗

PubMed2000

Imprint switching for non-random X-chromosome inactivation during mouse oocyte growth.

In mammals, X-chromosome inactivation occurs in all female cells, leaving only a single active X chromosome. This serves to equalise the dosage of X-linked genes in male and female cells. In the mouse, the paternally derived X chromosome (X(P)) is imprinted and preferentially inactivated in the extraembryonic tissues whereas in the embryonic tissues inactivation is random. To investigate how X(P) is chosen as an inactivated X chromosome in the extraembryonic cells, we have produced experimental embryos by serial nuclear transplantation from non-growing (ng) oocytes and fully grown (fg) oocytes, in which the X chromosomes are marked with (1) an X-linked lacZ reporter gene to assay X-chromosome activity, or (2) the Rb(X.9)6H translocation as a cytogenetic marker for studying replication timing. In the extraembryonic tissues of these ng/fg embryos, the maternal X chromosome (X(M)) derived from the ng oocyte was preferentially inactivated whereas that from the fg oocyte remained active. However, in the embryonic tissues, X inactivation was random. This suggests that (1) a maternal imprint is set on the X(M) during oocyte growth, (2) the maternal imprint serves to render the X(M) resistant to inactivation in the extraembryonic tissues and (3) the X(M) derived from an ng oocyte resembles a normal X(P).

Amnion↗

PubMed1999

Characterization of two chloroplast RNA polymerase sigma factors from Zea mays: photoregulation and differential expression.

Two distinct cDNAs encoding putative sigma factors of plastid RNA polymerase were isolated from Zea mays, a C4 plant. The deduced amino acid sequences of both cDNAs possess all four highly conserved domains proposed for recognition of -10 and -35 promoter elements, core complex binding, DNA binding, and melting. These two cDNAs are designated sig1 and sig2. Phylogenetic analysis of available plastid sigma factors indicated that they were probably the descendants of cyanobacterial principal sigma factors. Southern blots probed with sig1 and sig2 revealed that both genes exist in the maize nuclear genome as single-copy genes, but low-stringency hybridization suggested the presence of a multigene family of maize plastid sigma factors. Transcription of sig1 and sig2 is light inducible and tissue specific. Transcripts of sig1 and sig2 were abundant in greening leaf tissues; sig2 (but not sig1) was barely detectable in etiolated leaves and neither was detectable in roots. Immunological studies using a peptide antibody against an epitope in subdomain 2.4 of Sig1 revealed 50-kDa and 60-kDa immunoreactive proteins in maize chloroplasts. Reduced levels of the 60-kDa immunoreactive protein were detected in etioplasts, and no immunoreactive proteins were observed in roots. Collectively, the data suggest that the nuclear genes, sig1 and sig2, may play a role in differential expression of plastid genes during chloroplast biogenesis.

Amino Acid Sequence↗

PubMed1999

A phylogenetic assessment of the eukaryotic light-harvesting antenna proteins, with implications for plastid evolution.

The light-harvesting complexes (LHCs) are a superfamily of chlorophyll-binding proteins present in all photosynthetic eukaryotes. The Lhc genes are nuclear-encoded, yet the pigment-protein complexes are localized to the thylakoid membrane and provide a marker to follow the evolutionary paths of plastids with different pigmentation. The LHCs are divided into the chlorophyll a/b-binding proteins of the green algae, euglenoids, and higher plants and the chlorophyll a/c-binding proteins of various algal taxa. This work examines the phylogenetic position of the LHCs from three additional taxa: the rhodophytes, the cryptophytes, and the chlorarachniophytes. Phylogenetic analysis of the LHC sequences provides strong statistical support for the clustering of the rhodophyte and cryptomonad LHC sequences within the chlorophyll a/c-binding protein lineage, which includes the fucoxanthin-chlorophyll proteins (FCP) of the heterokonts and the intrinsic peridinin-chlorophyll proteins (iPCP) of the dinoflagellates. These associations suggest that plastids from the heterokonts, haptophytes, cryptomonads, and the dinoflagellate, Amphidinium, evolved from a red algal-like ancestor. The Chlorarachnion LHC is part of the chlorophyll a/b-binding protein assemblage, consistent with pigmentation, providing further evidence that its plastid evolved from a green algal secondary endosymbiosis. The Chlorarachnion LHC sequences cluster with the green algal LHCs that are predominantly associated with photosystem II (LHCII). This suggests that the green algal endosymbiont that evolved into the Chlorarachnion plastid was acquired following the emergence of distinct LHCI and LHCII complexes.

Amino Acid Sequence↗

PubMed1999

A prospective comparison of brain contrast characteristics and lesion detection using single-shot fast spin-echo and fast spin-echo.

MRI is limited by movement artefact, even with current imagers, when examining a restless or claustrophobic patient. We prospectively analysed the images of 92 patients produced by a single-shot fast spin-echo (SSFSE) pulse sequence and compared them with conventional (FSE) and reduced-time fast spin-echo (RT-FSE) techniques, with regard to lesion detection and movement artefact in brain imaging. Images obtained in each case were independently reviewed and scored for overall diagnosis, number of lesions detected, and movement artefact. FSE showed 1217 lesions, RT-FSE 1137, and SSFSE 1044. This discrepancy arose mainly in patients with multiple sclerosis or small-vessel disease, since with SSFSE we were less able to separate small, adjacent low-contrast lesions than with FSE. Arbitrary movement scores were 36, 25 and zero respectively. There were, however, no clinically significant differences in overall diagnosis between the three techniques. SSFSE thus proved a reliable, fast, accurate method for obtaining T2-weighted images, and may be of particular use in the restless, claustrophobic or obtunded patient.

Algorithms↗

PubMed1999

Antibacterial action of bile acids against Helicobacter pylori and changes in its ultrastructural morphology: effect of unconjugated dihydroxy bile acid.

Although it has been shown that bile acids possess antibacterial activity against Helicobacter pylori, few reports on their activity have been published. We determined the minimum inhibitory concentration at 72 h of various unconjugated and conjugated bile acids against laboratory standard strains and clinical isolates of H. pylori, and studied morphologic changes of H. pylori under the scanning electron microscope during treatment with deoxycholic acid and ursodeoxycholic acid at the minimum inhibitory concentrations for 24 h. We found that only the unconjugated form of dihydroxy bile acid has antibacterial activity. The minimum inhibitory concentration of deoxycholic acid is 200-400 microg/ml, that of chenodeoxycholic acid is similar to that of deoxycholic acid, and that of ursodeoxycholic acid is 400-800 microg/ml. The morphology of H. pylori changed from its primary rodlike shape to a spherical shape with blebs on the cell surface, and was further degraded to an irregularly condensed mass, following an increase in bile acid. This morphologic change in H. pylori was different from the change to a spherical shape caused by amoxicillin. On the basis of these results, it seems that unconjugated dihydroxy bile acid might be a candidate drug for eradication of H. pylori, but further investigations of the clinical usefulness of bile acid for this purpose should be done.

Bile Acids and Salts↗

PubMed1999

Pharmacological studies on synthetic flavonoids: comparison with diazepam.

The present experiments compared the central BZ-omega binding characteristics and pharmacological profiles of two synthetic flavonoids (6-bromoflavone and 6-bromo-3'-nitroflavone) with those of the benzodiazepine (BZ) diazepam. In vitro experiments showed that while diazepam displaced [3H]flumazenil binding to the GABA(A) receptor in membranes from rat cerebellum and spinal cord, two brain areas enriched in the BZ-omega1 and BZ-omega2 receptor subtypes, with nearly equivalent half maximally effective concentrations, 6-bromo-3'-nitroflavone was somewhat more potent in displacing [3H]flumazenil binding to membranes from rat cerebellum (IC50 = 31 nM) than from spinal cord (IC50 = 120 nM), indicating selectivity for the BZ-omega1 receptor subtype. 6-Bromoflavone displayed weak (IC50 = 970 nM) affinity for the BZ-omega1 and no affinity for the BZ-omega2 (IC50 > 1000 nM) receptor subtypes. Diazepam, but not the synthetic flavonoids increased the latency to clonic seizures produced by isoniazid, thereby indicating that neither 6-bromoflavone nor 6-bromo-3'-nitroflavone display detectable intrinsic activity at GABA(A) receptors in vivo. Results from two conflict tests in rats showed that 6-bromoflavone (3-10 mg/kg) and 6-bromo-3'-nitroflavone (0.3-1 mg/kg) elicited anxiolytic-like activity in the punished drinking test, while both drugs were inactive in the punished lever pressing test. The positive effects displayed by the synthetic flavonoids in the punished drinking procedure were smaller than that of diazepam and were not antagonized by the BZ receptor antagonist flumazenil. In two models of exploratory activity, 6-bromoflavone (3-30 mg/kg) and 6-bromo-3'-nitroflavone (0.3-1 mg/kg) produced anxiolytic-like effects in the rat elevated plus-maze test, whereas both compounds failed to modify the behavior of mice in the light/dark test over a wide dose-range. The effects in the elevated plus-maze were antagonized by flumazenil. In the mouse defense test battery, where mice were confronted with a natural threat (a rat), 6-bromoflavone and 6-bromo-3'-nitroflavone failed to decrease flight reactions after the rat was introduced into the test area and risk assessment behavior displayed when subjects were constrained in a straight alley, and only weakly affected risk assessment of mice chased by the rat and defensive biting upon forced contact with the threat stimulus. In a drug discrimination experiment 6-bromoflavone and 6-bromo-3'-nitroflavone up to 30 and 3 mg/kg, respectively, did not substitute for the BZ chlordiazepoxide. Taken together, these results failed to demonstrate that the synthetic flavonoids 6-bromoflavone and 6-bromo-3'-nitroflavone possess anxiolytic-like properties similar or superior to that of diazepam, as was suggested previously. Furthermore, they question the contribution of BZ-omega receptors to the behavioral effects of 6-bromoflavone and 6-bromo-3'-nitroflavone.

Animals↗

PubMed1999

Synthesis and benzodiazepine receptor (omega receptor) affinities of 3-substituted derivatives of pyrrolo[2,3-c]pyridine-5-carboxylate, a novel class of omega1 selective ligands.

Based on the structure of ZK91296 (4d), a high affinity partial agonist of the central benzodiazepine (omega) receptor, a series of pyrrolo[2,3-c]pyridine-5-carboxylate derivatives having mainly aralkyl and aralkyloxy substituents at C-3 was synthesized. The in vitro binding affinities of these compounds for three subclasses of the omega receptor (omega1, omega2, omega5) were determined using rat brain tissue. Practically all of these compounds (except the diethyl ester derivative 22c) showed an approximately twofold selectivity for omega1 (IC50's in the 200-500 nM range) compared to omega2 receptors and practically no affinity for omega5 receptors. Compound 22c showed the highest affinity of all the compounds synthesized (IC50 = 70 nM for omega1 receptors) as well as a fivefold selectivity for omega1 versus omega2 receptors but also displayed significant binding to omega5 receptors (IC50 = 250 nM). The absence of appreciable binding of 4-methyl and 4-methoxymethyl derivatives to omega receptors, in contrast to beta-carbolines having these similarly located substituents, suggests that the pyrrolo[2,3-c]pyridine-5-carboxylates may be considered an entirely novel class of selective omega receptor ligands.

Animals↗

PubMed1999

Orbital and globe rotation: the role of the periorbita.

We hypothesize that excyclorotation of the globe and extraocular muscle cone associated with external orbital rotation around each orbital axis in craniofacial conditions could be at least partially corrected by leaving the anterior periorbita (periosteum lining the orbit) attached to the surgically rotated portion of the orbit. This hypothesis was tested by comparing the degree of rotation of the globe in response to internal rotation of the anterior orbit, leaving the periorbita attached to the rotated portion of the orbit on one (study) side, and stripping the periorbita on the opposite (control) side, in nine fresh cadavers. There was a highly significant difference (P < 0.0001) between the study and control sides. The possible extrapolations of this finding to the clinical situation are discussed.

Analysis of Variance↗

PubMed1999

Identification and characterization of a novel rat triosephosphate isomerase gene in remnant ileum after massive small bowel resection.

This paper describes the identification and characterization of a novel cDNA encoding a putative protein of 254 amino acids that is highly homologous to triosephosphate isomerase. The cDNA was isolated by subtractive hybridization and was differentially expressed in the remnant rat ileum after massive small bowel resection. The novel triosephosphate isomerase was named rsTPI (resection-induced TPI) and the putative protein encoded RSTPI. The nucleotide and amino acid sequences of rsTPI and RSTPI were about 60% and 62% homologous to Giardia lamblia TPI and TPI, respectively. Active catalytic sites (Lys 13, His 95, and Glu 167) and the peptide motifs, AYEPVWSIGT and GGASLKPEF found in other triosephosphate isomerases were conserved in RSTPI. rsTPI expression was detected in normal ileum and pancreas by reverse transcription-polymerase chain reaction. Expression of rsTPI in remnant rat ileum was detectable by northern blot analysis one week after massive small bowel resection. Expression increased significantly by 2.8-fold between one and two weeks after surgery. High levels were maintained for at least one month after surgery. The up-regulation of triosephosphate isomerase expression in the remnant small intestine after massive resection indicates that it may play an important role in the adaptive process.

Adaptation, Physiological↗

PubMed1999

Increased injury following intermittent fetal hypoxia-reoxygenation is associated with increased free radical production in fetal rabbit brain.

Hypoxia associated with perinatal events can result in brain damage in the neonate. In labor and eclampsia, hypoxia can be intermittent, which may result in more severe damage than sustained hypoxia. The pathogenesis of brain injury in sustained ischemia involves free radical production; therefore, we investigated whether higher levels of free radicals contribute to the greater injury induced by repetitive ischemia. Brains were obtained from fetuses of near-term, pregnant rabbits subjected to repetitive ischemia-reperfusion (RIR), sustained uterine ischemia-reperfusion (IR), or a control protocol. Compared with controls, fetal brains from RIR or IR groups had more brain edema. Brains from RIR fetuses exhibited higher levels of lipid peroxidation, 3-nitrotyrosine, and nitrogen oxides, and lower total antioxidant capacity and cortical cellular viability than those of IR or control fetuses. Maternal administration of antioxidants following RIR and fetal bradycardia resulted in lower levels of fetal cortical and hippocampal cell death. Coadministration of Trolox and ascorbic acid resulted in less brain edema and liquefaction, and fewer hippocampal ischemic nuclei as compared with the saline control. Higher free radical production may be responsible for the greater fetal brain injury following repetitive hypoxia-reoxygenation. Maternal antioxidant treatment resulted in transplacental passage of antioxidants and amelioration of brain injury, and may be a viable clinical option following diagnosis of fetal distress.

Animals↗

PubMed1999

Comparison of the pharmacological properties of classical and novel BZ-omega receptor ligands.

The experiments in this study compared the pharmacological properties of several BZ-omega receptor ligands, including the imidazobenzodiazepine imidazenil, the beta-carboline abecarnil, the pyridazinone Y-23684, the pyrido [1,2-a]benzimidazole RWJ 46771 and the 1,6-naphthyridin-2(1H)-one derivative SX-3228, with the prototypical BZs diazepam, clobazam and bretazenil. In in vitro experiments diazepam, bretazenil, imidazenil and Y-23684 displaced [3H]flumazenil binding non-selectively in membranes from rat cerebellum and spinal cord, two brain areas enriched in the BZ-omega 1 and BZ-omega 2 receptor subtypes, respectively. In contrast, abecarnil, RWJ 46771 and SX-3228 were more potent in displacing [3H]flumazenil binding to membranes from rat cerebellum than from spinal cord or hippocampus, indicating selectivity for the BZ-omega 1 receptor subtype. The in vivo experiments showed that all compounds increased the latency to clonic seizures produced by isoniazid. However, the maximal increase in latency induced by diazepam, clobazam, abecarnil, RWJ 46771 and SX-3228 was greater than that of bretazenil, imidazenil and Y-23684, thereby indicating that these latter compounds have low intrinsic efficacy. In the punished drinking, the punished lever pressing and the elevated plus-maze tests in rats, three models of anxiety, diazepam, clobazam and imidazenil elicited clear anxiolytic-like effects but at doses which were close to those producing hypolocomotion, ataxia and myorelaxation as measured in activity cages, the rotarod and the loaded grid tests, respectively. In contrast, bretazenil and Y-23684 induced anxiolytic-like activity at much lower doses than those which impaired motor performances. The magnitude of the positive effects of Y-23684 was similar to that of the reference BZs, suggesting that it may become a valuable alternative to currently used agents for the treatment of anxiety disorders. Abecarnil, RWJ 46771 and SX-3228 produced weaker or non-specific anxiolytic-like effects as they decreased anxiety-related behaviours at doses similar or close to those impairing motor performance. However, unlike the other compounds they induced myorelaxation at doses which were 3-10 times higher than those needed to produce decrease in exploratory activity. It is suggested that the behavioural profiles of abecarnil, RWJ 46771 and SX-3228 may be attributed to their selectivity for the BZ-omega 1 receptor subtype which may account for their sedative activity, thereby masking other effects including anxiolytic-like activity. This suggests that BZ receptor modulation of anxiety may involve BZ receptor subtypes other than BZ-omega 1.

Animals↗

PubMed1999

Molecular mimetics of polysaccharide epitopes as vaccine candidates for prevention of Neisseria meningitidis serogroup B disease.

Neisseria meningitidis is a major cause of meningitis and sepsis. Despite nearly 25 years of work, there is no promising vaccine candidate for prevention of disease caused by meningococcal B strains. This review summarizes newer approaches for eliciting protective meningococcal B immune responses, including the use of molecular mimetics of group B polysaccharide and conserved membrane proteins as immunogens. The capsular polysaccharide of this organism is conserved and serum antibody to this capsule confers protection against disease. However, the immunogenicity of meningococcal B polysaccharide-based vaccines is poor. Further, a portion of the antibody elicited has autoantibody activity. Recently, our laboratory produced a panel of murine monoclonal antibodies (Mabs) that react specifically with capsular polysaccharide epitopes on meningococcal B that are distinct from host polysialic acid. These Mabs elicit complement-mediated bactericidal activity and confer passive protection in animal models. The anti-capsular Mabs were used to identify molecular mimetics from phage display peptide libraries. The resulting peptides were antigenic mimetics as defined by binding to the Mabs used to select them but, to date, are poor immunogenic mimetics in failing to elicit anti-capsular antibodies.

Animals↗

PubMed1999

Differences in surface expression of NspA among Neisseria meningitidis group B strains.

NspA is a highly conserved membrane protein that is reported to elicit protective antibody responses against Neisseria meningitidis serogroups A, B and C in mice (D. Martin, N. Cadieux, J. Hanel, and B. R. Brodeur, J. Exp. Med. 185:1173-1183, 1997). To investigate the vaccine potential of NspA, we produced mouse anti-recombinant NspA (rNspA) antisera, which were used to evaluate the accessibility of NspA epitopes on the surface of different serogroup B strains by an immunofluorescence flow cytometric assay and by susceptibility to antibody-dependent, complement-mediated bacteriolysis. Among 17 genetically diverse strains tested, 11 (65%) were positive for NspA cell surface epitopes and 6 (35%) were negative. All six negative strains also were resistant to bactericidal activity induced by the anti-rNspA antiserum. In contrast, of the 11 NspA surface-positive strains, 8 (73%; P < 0.05) were killed by the antiserum and complement. In infant rats challenged with one of these eight strains, the anti-rNspA antiserum conferred protection against bacteremia, whereas the antiserum failed to protect rats challenged by one of the six NspA cell surface-negative strains. Neither NspA expression nor protein sequence accounted for differences in NspA surface accessibility, since all six negative strains expressed NspA in outer membrane preparations and since their predicted NspA amino acid sequences were 99 to 100% identical to those of three representative positive strains. However, the six NspA cell surface-negative strains produced, on average, larger amounts of group B polysaccharide than did the 11 positive strains (reciprocal geometric mean titers, 676 and 224, respectively; P < 0.05), which suggests that the capsule may limit the accessibility of NspA surface epitopes. Given these strain differences in NspA surface accessibility, an rNspA-based meningococcal B vaccine may have to be supplemented by additional antigens.

Amino Acid Sequence↗

PubMed1999

Effects of genetic polymorphism on ex vivo and in vivo function of beta2-adrenoceptors in asthmatic patients.

BACKGROUND: Genetic polymorphism determines agonist-induced down-regulation and desensitization of beta2-adrenoceptors. OBJECTIVES: The aim of the present study was to investigate the effects of genetic polymorphism on ex vivo (lymphocytes) and in vivo (bronchoprotection) function of beta2-adrenoceptors in asthmatic patients, having been washed out of previous beta2-agonist exposure. METHODS: Sixty patients with stable mild-to-moderate asthma were evaluated, with a post hoc analysis of genotype performed at end of study. Having withheld treatment with long-acting beta2-agonists for > or = 48 h and short-acting beta2-agonists for > or = 12 h, measurements of lymphocyte beta2-adrenoceptors were made for binding density, binding affinity, basal cyclic adenosine monophosphate (cAMP), and maximal cAMP response to isoproterenol (Emax). In addition, in 48 of these patients who were methacholine responsive (PD20 < 1,000 microg), the acute protective effect of formoterol as a 24-microg single dose (at 1 h) was also evaluated. Comparisons were made according to homozygous and heterozygous (Het) polymorphisms at codon 16 and codon 27. RESULTS: There were no significant differences in age, FEV1 percent predicted, or inhaled corticosteroid dose, when comparing mean values for polymorphisms at either codon-16 or codon 27. There were also no significant differences between polymorphisms for any of the measured lymphocyte beta2-adrenoceptor parameters apart from basal cAMP between Glu-27 and Het-27. Mean values for Emax (after-before isoproterenol as pmol/10(6) cells) were as follows: Gly-16 (3.4), Arg-16 (3.5), Het-16 (4.0), Glu-27 (3.9), Gln-27 (3.5), and Het-27 (3.7). Polylorphism had no significant effect on formoterol protection as doubling dose shift in methacholine PD20 (geometric mean): Gly-16 (5.3), Arg-16 (5.4), Het-16 (4.6), Glu-27 (5.3), Gln-27 (5.3), Het-27 (4.5). CONCLUSIONS: Our results show that genetic polymorphism at codon 16 or 27 does not influence stimulated coupling of lymphocyte beta2-adrenoceptors and similarly did not influence the degree of functional antagonism exhibited by formoterol. Thus, a single dose of beta2-agonist when used on demand affords equal protection against bronchoprotection regardless of genetic polymorphism.

Adenylyl Cyclases↗

PubMed1999

Preserving brain function during neonatal asphyxia.

Presently, there is no intervention that can be used that preserves brain function in hypoxic-ischemic encephalopathy. This review covers the interventional strategies that are available to the health care worker at present and suggests a different approach to this frustrating problem. The proposal is to use clinically available interventions and combine them into an effective intervention strategy. The merits of each intervention is discussed.

Antioxidants↗