Effects of dopaminergic agents on carrageenan hyperalgesia in rats

The present study explored the role of central dopaminergic transmission in a model of carrageenan-induced inflammatory pain by examining the effects of selective agonists and antagonists of dopamine receptors. The results were as follow: (1) LY171555 (trans-(-)-4aR-4,4a,5,6,7,8,8a,9-Octahydro-5-propyl-1H-pyrazolo[3, 4-g]quinoline hydrochloride), dopamine D(2) receptor agonist, produced anti-hyperalgesia or hypoalgesia in the inflamed hindpaws and non-inflamed hindpaws, respectively; spiperone hydrochloride (8-[4-(4-Fluorophenyl)-4-oxobutyl]-1-phenyl-1,3,8-triazaspiro[4, 5]decan-4-one hydrochloride), dopamine D(2) receptor antagonist, decreased the pain threshold of the non-inflamed hindpaws. (2) (+/-)-SKF38393 hydrochloride ((+/-)-1-Phenyl-2,3,4, 5-tetrahydro-(1H)-3-benzazepine-7,8-diol hydrochloride), dopamine D(1) receptor agonist, produced anti-hyperalgesia or hypoalgesia when administered in a high dose (600 nmol), and decreased the pain threshold of non-inflamed hindpaws when administered in a low dose (150 nmol); R(+)-SCH23390 hydrochloride (R(+)-7-Chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4, 5-tetrahydro-1H-3-benzazepine hydrochloride), dopamine D(1) receptor antagonist, induced anti-hyperalgesia or hypoalgesia, respectively. The present study suggests that the dopaminergic system is involved in the central modulation of inflammatory hyperalgesia, and that the different effects are probably induced by the different receptors.

Solution structure of BmP01 from the venom of scorpion Buthus martensii Karsch

From the venom of scorpion Buthus martensii Karsch,a short peptide (BmP01, 29 amino acid residues) was isolated and characterized as previously reported (Lebren, R. R., et al. (1997) Eur. J. Biochem. 245, 457-464). It was shown to reduce 33% outward K(+) channel (hippocampal neurons) currents at 10 microM. The solution structure of BmP01 was determined by 2D (1)H NMR spectroscopy. The NOEs, coupling constants, and H-D exchange obtained from NMR spectroscopy were used in structural calculations. The conformation of BmP01 is composed of a short alpha-helix (Cys 3-Thr 12) and a two-stranded antiparallel beta-sheet (Ala 15-Asp 20 and Lys 23-Pro 28). There are three disulfide bridges (Cys 3-Cys 19, Cys 6-Cys 24 and Cys 10-Cys 26) connecting the alpha-helix and beta-sheet. Asp 20 to Lys 23 form a type II turn linking the two strands. Structural and electrostatic potential comparison between BmP01 and its analogues are also presented.

[Individual tree growth-competition model in mixed plantation of manchurian ash and dahurian larch]

Based on distance-dependent competition models and neighborhood interference models, the competition index components and competition effect coefficients were used to quantify the spatial competition among trees in the mixed plantation of ash(Fraxinus mandshurica) and larch(Larix gmelini). Taking each component of competition index as independent variables and the yearly volume growth as dependent variable, the competition-growth model was established with good regression result. The study provided a new approach to deal with the further improvement of spatial competition models and the plant competition-growth relationship ecological study.

[Application of competition index in assessing intraspecific and interspecific spatial relations between manchurian ash and dahurian larch]

The competition among trees within a stand includes aboveground and underground parts. How to determine the zone of competition influence is important for predicting tree growth. We divide the zone into two parts: one part is defined as inside radius, the distance from nearest competitors to subject tree, in which, the competition influence is the sum of both aboveground and underground; the another part is defined as outside radius, the distance of competitors to subject tree, where the competition influence comes mostly from underground. Thus, the competition index, based upon the divided two radii, could be decomposed into different components. We used the data of manchurian ash(MA) (Fraxinus mandshurica) and dahurian larch(DL) (Larix gmelini) from pure and mixed stands to analyze the competition influence of aboveground and underground in inside and of underground in outside radius. The results show that for MA in pure stand, the competition effect was 59.06% from inside radius, and 40.94% from outside radius. For DL in pure stand, the competition effects in both radii were 71.31% and 28.69%, respectively. There was a stronger competition influence in inside than in outside radius. Underground competitions were the important issues for both species in pure stands. In a mixed stand of MA and DL, there were two species in both radii, and the effects of competition came from intraspecific and interspecific competitors. For subject tree of MA, the effect of interspecific competition was 49.55%, and that of intraspecific was 50.45%. For subject tree of DL, the effects were 81.11% and 18.89%, respectively. DL displayed a stronger interspecific competition than MA in the zone of competition influence, and was a main effect of competition on MA. For subject tree of MA, the effect of competition from inside radius was 25.33%, which was the sum of competition influence from aboveground and underground, and about 74.67% was from outside radius. For subject tree of DL, both in inside and outside radii were 55.37% and 44.64%, respectively. Comparing with the information from both species and two radii, the root-root competition from underground was an important component. DL grew well, and could reduce the impact of intraspecific competition for MA when both species mixed in a stand.

[Study of differential expressed genes in vascular endothelial cell line ECV304 induced by low density lipoprotein]

OBJECTIVE

To isolate and clone the differential expressed genes induced by atherogenic factors on vascular endothelium and to understand the molecular mechanism of atherosclerosis.

METHODS

The differential display reverse transcription PCR method (DDRT-PCR) was used to analyze the differential expressed cDNA in ECV304 induced by low density lipoprotein (LDL). After sequencing and homology research, the differential expressed cDNA fragments were confirmed by northern blot analysis.

RESULTS

Up-regulated and down-regulated cDNAs fragments were isolated in ECV304. It was found that some cDNAs fragments were highly homologous to the known human genes, while others were fragments of novel genes. The known up-regulated genes included human 10 kD protein, FGFR1 oncogene partner, intercellular adhesion molecular-1, FK506 binding protein and rTS beta genes. The known down-regulated genes included human fb19, Apobec1-binding protein 1 and RBP2. The expression levels of different genes varied by 70%-200%.

CONCLUSION

By DDRT-PCR method, our results showed that LDL could change the expression of many genes in endothelial cells. The high expression level of ICAM-1 in the endothelial cells stimulated by LDL suggested that ICAM-1 is an important adhesion molecular in atherogenesis. The down-regulated expression of Apobec 1-binding protein 1 may affect the cellular synthesis of apolipoprotein. The high expression level of FGFR1 oncogene partner is likely related to the differentiation of ECV304. The function of other differential expressed genes remains to be elucidated.

The preparation and characterization of an immobilized l-glutamic decarboxylase and its application for determination of l-glutamic acid

This paper is to study the preparation and characterization of an immobilized L-glutamic decarboxylase (GDC) and develop a sensitive method for the determination of L-glutamate using a new biosensor, which consists of an enzyme column reactor of GDC immobilized on a novel ion exchange resin (carboxymethyl-copolymer of allyl dextran and N.N'-methylene-bisacrylamide CM-CADB) and ion analyzer coupled with a CO(2) electrode. The conditions for the enzyme immobilization were optimized by the parameters: buffer composition and concentration, adsorption equilibration time, amount of enzyme, temperature, ionic strength and pH. The dynamic response of Na(2)HPO(4)-citric acid buffer system selected is much better than that of the others, 0.10 M HAc-0.10 M NaAc and 0.10 M sodium citrate-0.10 M citric acid. The initial rate of the enzyme reaction v(0) in this buffer system is 1.76 mol. l(-1) min(-1), moreover, the rate of the enzyme reaction appears linear in the first 4 min. The optimum adsorption equilibrium time is around 6 h. The amount of enzyme adsorbed on CM-CADB resin affects the response to substrate L-glutamic acid, the widest range of linearity is obtained with over 30 mg (GDC)/g(resin). The GDC activity immobilized on CM-CADB reaches a maximum when the immobilization temperature was kept around 40 degrees C. pH was kept at 4.4 when measuring the activity of the immobilized GDC. No variation of the activity of immobilized GDC is observed when the capacity is over 2.5 meq/g.(CM-CADB resin). The properties of the immobilized enzyme on CM-CADB were characterized. No significant improvement can be achieved when the substrate concentration exceeds 12.00 mmol/l, where the activity of immobilized GDC is equal to 1.58 mmol/l.min.g. The optimum pH is found to be 5.2, which changes 0.2 unit, comparing with that of the free GDC (5.0). The optimum temperature is found to be around 48 degrees C, which is lower than that of free GDC (55 degrees C). The critical temperature of the free GDC and the immobilized GDC is approximately 50 degrees C and 45 degrees C, respectively. The half-life of the activity is 127 days when the immobilized enzyme was stored in the cold (4 degrees C). An immobilized GDC enzyme column reactor matched with a flow injection system-ion analyzer coupled with CO(2) electrode-data collection system made up the original form of the apparatus of biosensor for determining of L-glutamic acid. The determination conditions are that the buffer solution is 0.10 M Na(2)HPO(4)-0.05 M citric acid at pH 4.4 and t = 37 degrees C. The limit of detection is 1.0 x 10(-)(5) M. The linearity response is in the range of 5 x 10 (-2) - 5 x 10 (-5) M. The equation of linear regression of the calibration curve is y = 43.3x + 181.6 (y is the milli-volt of electrical potential response, x is the logarithm of the concentration of the substrate of L-glutamic acid). The correlation coefficient equals 0.99. The coefficient of variation equals 2.7%.

Epsilon protein kinase C in pathological myocardial hypertrophy. Analysis by combined transgenic expression of translocation modifiers and Galphaq

The epsilon isoform of protein kinase C (PKC) has a critical cardiotrophic function in normal postnatal developing heart as demonstrated by cardiac-specific transgenic expression of epsilonPKC-selective translocation inhibitor (epsilonV1) and activator (psiepsilonRACK) peptides (Mochly-Rosen, D., Wu, G., Hahn, H., Osinska, H., Liron, T., Lorenz, J. N., Robbins, J., and Dorn, G. W., II (2000) Circ. Res. 86, 1173-1179). To define the role of epsilonPKC signaling in pathological myocardial hypertrophy, epsilonV1 or psiepsilonRACK were co-expressed in mouse hearts with Galpha(q), a PKC-linked hypertrophy signal transducer. Compared with Galpha(q) overexpression alone, co-expression of psiepsilonRACK with Galpha(q) increased epsilonPKC particulate partitioning by 30 +/- 2%, whereas co-expression of epsilonV1 with Galpha(q) reduced particulate-associated epsilonPKC by 22 +/- 1%. Facilitation of epsilonPKC translocation by psiepsilonRACK in Galpha(q) mice improved cardiac contractile function measured as left ventricular fractional shortening (30 +/- 3% Galpha(q) versus 43 +/- 2% psiepsilonRACK/Galpha(q), p < 0.05). Conversely, inhibition of epsilonPKC by epsilonV1 modified the Galpha(q) nonfailing hypertrophy phenotype to that of a lethal dilated cardiomyopathy. These opposing effects of epsilonPKC translocation activation and inhibition in Galpha(q) hypertrophy indicate that epsilonPKC signaling is a compensatory event in myocardial hypertrophy, rather than a pathological event, and support the possible therapeutic efficacy of selective epsilonPKC translocation enhancement in cardiac insufficiency.

NBS1 and TRF1 colocalize at promyelocytic leukemia bodies during late S/G2 phases in immortalized telomerase-negative cells. Implication of NBS1 in alternative lengthening of telomeres

Nijmegen breakage syndrome, a chromosomal instability disorder, is characterized in part by cellular hypersensitivity to ionizing radiation. The NBS1 gene product, p95 (NBS1 or nibrin) forms a complex with Rad50 and Mre11. Cells deficient in the formation of this complex are defective in DNA double-strand break repair, cell cycle checkpoint control, and telomere length maintenance. How the NBS1 complex is involved in telomere length maintenance remains unclear. Here we show that the C-terminal region of NBS1 interacts directly with a telomere repeat binding factor, TRF1, by both yeast two-hybrid and in vivo DNA-coimmunoprecipitation assays. NBS1 and Mre11 colocalize with TRF1 at promyelocytic leukemia (PML) nuclear bodies in immortalized telomerase-negative cell lines, but rarely in telomerase-positive cell lines. The translocation of NBS1 to PML bodies occurs specifically during late S to G(2) phases of the cell cycle and coincides with active DNA synthesis in these NBS1-containing PML bodies. These results suggest that NBS1 may be involved in alternative lengthening of telomeres in telomerase-negative immortalized cells.

Rapid determination of nitrite by reversed-phase high-performance liquid chromatography with fluorescence detection

Measurement of nitrite and nitrate, the stable oxidation products of nitric oxide (NO), provides a useful tool to study NO synthesis in vivo and in cell cultures. A simple and rapid fluorometric HPLC method was developed for determination of nitrite through its derivatization with 2,3-diaminonaphthalene (DAN). Nitrite, in standard solution, cell culture medium, or biological samples, readily reacted with DAN under acidic conditions to yield the highly fluorescent 2,3-naphthotriazole (NAT). For analysis of nitrate, it was converted to nitrite by nitrate reductase, followed by the derivatization of nitrite with DAN to form NAT. NAT was separated on a 5-microm reversed-phase C18 column (150X4.6 mm, I.D.) guarded by a 40-microm reversed-phase C18 column (50x4.6 mm, I.D.), and eluted with 15 mM sodium phosphate buffer (pH 7.5) containing 50% methanol (flow-rate, 1.3 ml/min). Fluorescence was monitored with excitation at 375 nm and emission at 415 nm. Mean retention time for NAT was 4.4 min. The fluorescence intensity of NAT was linear with nitrite or nitrate concentrations ranging from 12.5 to 2,000 nM in water, cell culture media, plasma and urine. The detection limit for nitrite and nitrate was 10 pmol/ml. Because NAT is well separated from DAN and other fluorescent components present in biological samples, our HPLC method offers the advantages of high sensitivity and specificity as well as easy automation for quantifying picomole levels of nitrite and nitrate in cell culture medium and biological samples.

Polymorphic CAG and GGN repeat lengths in the androgen receptor gene and prostate cancer risk: a population-based case-control study in China

The length of the polymorphic CAG trinucleotide repeat in the polyglutamine region of the androgen receptor (AR) gene is inversely correlated with the transactivation function of the AR. Because increased androgenic activity has been linked to prostate cancer and because an ethnic variation exists in the CAG repeat length, this polymorphism has been suggested to explain part of the substantial racial difference in prostate cancer risk. We conducted a population-based case-control study in China to investigate whether CAG and other polymorphisms of the AR gene are associated with clinically significant prostate cancer in this low-risk population. Genomic DNA from 190 prostate cancer patients and 304 healthy controls was used for direct sequencing to evaluate the relationship of CAG and GGN (polyglycine) repeat length in the AR gene. Relative to western men, our study subjects had a longer CAG repeat length, with a median of 23 and only 10% of the subjects having a CAG repeat length shorter than 20. Men with a CAG repeat length shorter than 23 (median length) had a 65% increased risk of prostate cancer (odds ratio, 1.65; 95% confidence interval, 1.14-2.39), compared with men with a CAG repeat length of 23 or longer. For the GGN tract (GGT3GGG1GGT2GGCn), based on the sequencing results from 481 samples, we are the first to show that although GGC regions in the polyglycine tract are highly variable, there are no mutations or polymorphisms in the GGT and GGG regions. More than 72% of the subjects had a GGN repeat length of 23, and those with a GGN repeat length shorter than 23 had a 12% increased risk of prostate cancer (95% confidence interval, 0.71-1.78), compared with those with > or = 23 GGN repeats. Our study not only confirms that Chinese men do have a longer CAG repeat length than western men but also represents the first population-based study to show that even in a very low-risk population, a shorter CAG repeat length confers a higher risk of clinically significant prostate cancer. These results imply that CAG repeat length can potentially serve as a useful marker to identify a subset of individuals at higher risk of developing clinically significant prostate cancer. Larger studies are needed to evaluate the combined effect of CAG and GGN repeats. Because of the significance of AR in prostate cancer, investigation of factors that interact with the polyglutamine region of the AR gene to alter AR function and modulate prostate cancer risk is an important area for future research.

Postnatal changes of plasma amino acids in suckling pigs

Amino acids, ammonia, urea, orotate, and nitrate plus nitrite (stable oxidation products of nitric oxide) were determined in plasma of 1- to 21-d-old suckling pigs. Jugular venous blood samples were obtained from pigs at 1, 3, 7, 14, and 21 d of age for analysis of plasma amino acids and metabolites by HPLC and enzymatic methods. Plasma concentrations of arginine and its immediate precursors (citrulline and ornithine) decreased (P < 0.01) progressively (20 to 41%) with increasing age from 3 to 14 d. Plasma concentrations of glutamine declined (P < 0.01) progressively (10 to 31%) during the 1st wk of life. Plasma concentrations of branched-chain amino acids, threonine, and alanine decreased (P < 0.01) (5 to 12%) in 14- and 21-d-old pigs, compared with 1- and 3-d-old pigs. There were no postnatal changes (P > 0.05) in plasma concentrations of other amino acids. Plasma concentrations of ammonia increased (P < 0.01) by 18 and 46%, whereas those of nitrate plus nitrite decreased (P < 0.01) by 16 and 29%, in 7- and 14-d-old pigs, respectively, compared with 1- to 3-d-old pigs. Because arginine plays a crucial role in ammonia detoxification via the hepatic urea cycle and is the physiological substrate for nitric oxide synthesis, our results of the decreased plasma concentrations of arginine and nitrate plus nitrite, as well as the increased plasma ammonia concentration, indicate a hitherto unrecognized deficiency of arginine in 7- to 21-d-old suckling pigs. Arginine is an essential amino acid for piglets and has a great potential to enhance neonatal growth; therefore, further studies are necessary to elucidate the mechanism responsible for arginine deficiency in sow-reared piglets and to identify hormonal and metabolic means for improving neonatal arginine nutrition and growth.

Notch4 and Jagged-1 induce microvessel differentiation of rat brain endothelial cells

The mouse Notch4 gene is expressed specifically in endothelial cells. Notch4/int-3, a truncated form of Notch4, acts as a constitutive activated Notch receptor. We used rat brain microvessel endothelial cells (RBE4) to study the role of Notch4 and Jagged-1 in endothelial cell differentiation. Both Notch4/int-3 and Jagged-1 were able to induce microvessel-like structures with morphological and biochemical properties similar to brain endothelial microvessels. Ectopic expression of full-length Notch4 did not effect RBE4 cells. Activation of the Notch signal transduction pathway was measured by the induction of endogenous Notch4 and Jagged-1 genes and of Jagged-1 proteins. The observed morphological changes to RBE4 cells correlated with endogenous Notch4 and Jagged-1 gene activation. Our observations demonstrate that Notch signaling can promote endothelial cell differentiation and morphogenesis.

Evidence of the synthesis of opioid receptor like 1 receptor in nociceptinergic neurons in rat brain suggests the existence of autoreceptor: a confocal double staining study

Opioid receptor like 1 (ORL1) receptor is a novel member of the opioid receptor family, which was not bound by any of the typical opioid receptor ligands but bound by the recently discovered nociceptin (also termed orphanin FQ) with high affinity. By using double staining of fluorescent in situ hybridization and immunohistochemistry, we observed the expression of ORL1 receptor mRNA in nociceptin-like immunoreactive neurons in multiple areas in rat brain including the hippocampus, arcuate nucleus in the hypothalamus, ventralateral periaquiductal gray (PAG) and raphe nuclei in brain stem. The expression of ORL1 mRNA in nociceptinergic neurons suggests that these receptors mediate, at least in part, the presynaptic autoreceptor functions. Further anatomical and functional significance of the autoreceptor of nociceptinergic neurons remain to be elucidated.

Frequency and Markov chain analysis of amino acid sequences of mouse p53

The amino acid sequence of mouse p53 was measured according to two- and three-amino-acid sequences. The measured frequency and probability were compared with predicted frequency and probability. Of 389 two-amino-acid sequences in mouse p53,85 (21.851%) and 27 (6.941%) sequences can be explained by the predicted frequency and probability according to a purelyrandom mechanism. Of 188 non-appearing two-amino-acid sequences in mouse p53, 86 (45.745%) and 32 (17.021%) can be explained by the predicted frequency and probability according to a purely random mechanism; no more than two-amino-acid sequences in mouse p53 can be explained by a purely random mechanism.

Infection by bacterial pathogens expressing type III secretion decreases luciferase activity: ramifications for reporter gene studies

Pathogenic microbes influence gene regulation in eukaryotic hosts. Reporter gene studies can define the roles of promoter regulatory sequences. The effect of pathogenic bacteria on reporter genes has not been examined. The aim of this study was to identify which reporter genes are reliable in studies concerning host gene regulation by bacterial pathogens expressing type III secretory systems. Human intestinal epithelial cells, T84, Caco-2 and HT-29, were transfected with plasmids containing luciferase (luc), chloramphenicol acetyltransferase (CAT) or beta-galactosidase (beta-gal) as reporter genes driven by the inducible interleukin-8 (IL-8) or constitutively active simian virus 40 (SV40) promoter. Cells were infected with enteropathogenic E. coli or Salmonella typhimurium, and the reporter activity was assessed. Luc activity significantly decreased following infection, regardless of the promoter. The activity of recombinant luc was nearly ablated by incubation with either EPEC or Salmonella in a cell-free system. Activity was partially preserved by protease inhibitors, and immunoblot analysis showed a decreased amount and molecular weight of recombinant luc, suggesting protein degradation. Neither beta-gal nor CAT activity was altered by infection. Disruption of type III secretion prevented the loss of luc activity. We conclude that CAT or beta-gal, but not luc, can be used as reliable reporter genes to assess the impact of pathogenic microbes, especially those expressing type III secretion on host cell gene regulation.

[Screening DPPH radical scavengers from Monascus sp]

A strain belongs to Monascus sp. was separated from hongqu(Chinese beni-coji) which was used to brew red wine in Changxin county, Zhejiang province, and its DPPH radical scavenging metabolites were studied. Results showed that the yield and radical scavenging activity of neutral extract with EtOAc were higher than that of acid and basic extract. After shaken at 30 degrees C, 100 r/min for 5 days, this strain produced largest amount of neutral extract. Further partitioning the neutral fraction with silica gel column chromatograph, LH-20 column chromatograph, MPLC and HPLC, we screened 15 free radical scavengers whose yield was more than 2 mg and purity was higher than 85% in HPLC (260 nm absorption). Several of them were analyzed with 1H-NMR and 13C-NMR spectrum from which we concluded that B1-3 and C3-1-7 were two kinds of substitute of benzene, and C3-1-7 may be 3-OH-4-OCH3-benzoic acid. The scavenging activity of 40 mumol/L B1-3 was about 65%, and that of C3-1-7 was lower than 56%, while as the control the scavenging activity of 40 mumol/L Vc and Ve was 80.4% and 78.4% respectively.

[Alternative splicing of de novo methyltransferase gene 3b in adult and newborn mice]

OBJECTIVE

To unravel the biological significance of the alternative splicing of de novo methyltransferase 3b, expression of the Dnmt3b gene in various tissues and developmental stages was investigated in postnatal mice.

METHODS

RT-PCR and capillary electrophoresis were employed to analyze the alternative splicing pattern of Dnmt3b in tissues of newborn and adult mice. The results had been further reaffirmed by repeating and statistics analysis. Bioinformatics tools were used to predict the structure and hydrophobicity of the Dnmt3b exon10 coding sequence.

RESULTS

Isoform with Dnmt3b exon10 was the abundant form in lung of newborn mice and in liver of both newborn and adult mice, while in other tissues of newborn and adult mice, the spliced isoform was presented as the predominant one. Peptide encoded by Dnmt3b exon10 was mainly random coil on the surface of Dnmt3b protein.

CONCLUSIONS

The data demonstrate that the specific expression of Dnmt3b exists in tissues and developmental stages of postnatal mice. The alternative splicing of the exon 10 of Dnmt3b is possibly involved in the regulation of Dnmt3b's catalytic function. These results provide an insight into the developmental regulation and physiological function of the alternative splicing of the Dnmt3b gene.

[Relationship between human activities and survival of rare and endangered species Davidia involucrata]

In recent years, the increasing intensity of human activities and the increase of regional developing items led to a sharp decrease of natural distributed area and natural population number of rare and endangered species Davidia involucrata, and now, its natural distributed population is on the point of extinction. This paper analyzed the geographic distribution situation of Davidia involucrata in different geologic and historical periods, and discussed the major reasons for forming the geographic distribution and dynamic changes of population. Through many field investigations and references, some protecting measures were presented.

Core histones of the amitochondriate protist, Giardia lamblia

Genes coding for the core histones H2a, H2b, H3, and H4 of Giardia lamblia were sequenced. A conserved organism- and gene-specific element, GRGCGCAGATTTVGG, was found upstream of the coding region in all core histone genes. The derived amino acid sequences of all four histones were similar to their homologs in other eukaryotes, although they were among the most divergent members of this protein family. Comparative protein structure modeling combined with energy evaluation of the resulting models indicated that the G. lamblia core histones individually and together can assume the same three-dimensional structures that were established by X-ray crystallography for Xenopus laevis histones and the nucleosome core particle. Since G. lamblia represents one of the earliest-diverging eukaryotes in many different molecular trees, the structure of its histones is potentially of relevance to understanding histone evolution. The G. lamblia proteins do not represent an intermediate stage between archaeal and eukaryotic histones.

A cortisol surge mediates the enhanced polyamine synthesis in porcine enterocytes during weaning

This study was conducted to determine whether a cortisol surge mediates the enhanced expression of intestinal ornithine decarboxylase (ODC) in weanling pigs. Piglets were nursed by sows until 21 days of age, when 40 pigs were randomly assigned into one of four groups (10 animals/group). Group 1 continued to be fed by sows, whereas groups 2-4 were weaned to a corn and soybean meal-based diet. Weanling pigs received intramuscular injections of vehicle solvent (sesame oil), RU-486 (a potent blocker of glucocorticoid receptors; 10 mg/kg body wt), and metyrapone (an inhibitor of adrenal cortisol synthesis; 5 mg/kg body wt), respectively, 5 min before weaning and 24 and 72 h later. At 29 days of age, pigs were used to prepare jejunal enterocytes for ODC assay and metabolic studies. To determine polyamine (putrescine, spermidine, and spermine) synthesis, enterocytes were incubated for 45 min at 37 degrees C in 2 ml Krebs-bicarbonate buffer containing 1 mM [U-(14)C]arginine, 1 mM [U-(14)C]ornithine, 1 mM [U-(14)C]glutamine, or 1 mM [U-(14)C]proline plus 1 mM glutamine. Weaning increased intestinal ODC activity by 230% and polyamine synthesis from ornithine, arginine, and proline by 72-157%. Arginine was a quantitatively more important substrate than proline for intestinal polyamine synthesis in weaned pigs. Administration of RU-486 or metyrapone to weanling pigs prevented the increases in intestinal ODC activity and polyamine synthesis, reduced intracellular polyamine concentrations, and decreased villus heights and intestinal growth. Our results demonstrate an essential role for a cortisol surge in enhancing intestinal polyamine synthesis during weaning, which may be of physiological importance for intestinal adaptation and remodeling.

[Determination of lidocaine in human spinal cord by high-performance liquid chromatography]

A RPHPLC method for determining lidocaine in human's spinal cord. Was established. The linear range of the method was 0.20-20.0 micrograms/ml(r = 0.9999). The detection limit was 0.02 ng/ml(S/N > or = 3) and the clean-up recovery of lidocaine in human spinal cord was 82.4%-92.7%. The CV% were no more than 6.0% (N = 4). No interfere by other compounds was observed in study results using this method. RPHPLC method shows an excellent recovery, high sensitivity and good precision.

Pig islet xenograft rejection is markedly delayed in macrophage-depleted mice: a study in streptozotocin diabetic animals

The present study aimed to evaluate the effect of depletion of macrophages and/or natural killer (NK) cells on islet xenograft rejection in the pig-to-mouse model. Five microliters (4,000 to 5,000 IEQ, islet equivalents) of adult pig islets were transplanted under the renal capsule of C57BL/6 mice with streptozotocin-induced diabetes. Macrophages were depleted by injection of liposome-encapsulated dichloromethylene diphosphonate (Lip-Cl2MDP) intraperitoneally (i.p.) at a dose of 100 microl/ 10 g body weight (BW) 2 days before transplantation, and 50 microl/10 g BW weekly thereafter. NK cells were depleted by injection of the monoclonal antibody NK 1.1 (anti-NK 1.1 mAb) i.p. at a dose of 100 microg/mouse 1 day before transplantation, and then 25 microg per week thereafter. Islet graft survival was monitored by daily measurements of blood glucose. Graft survival was 8 +/- 1.2 days in untreated controls, 9 +/- 1.0 days with anti-NK 1.1 mAb alone, 22 +/- 4.9 days with Lip-Cl2MDP alone (P<0.01 vs. controls), and 26 +/- 3.8 days with Lip-Cl2MDP plus anti-NK 1.1 mAb (P<0.01 vs. controls). In the last group, two of six animals were killed with functioning grafts 30 days after transplantation. In untreated controls, rejected xenografts were heavily infiltrated by F4/80+ macrophages and CD3+T cells. In Lip-Cl2MDP-treated groups, the number of F4/80+ macrophages was markedly reduced. On the periphery of xenografts, a small number of CD3+T cells were observed. In conclusion, our results suggest that strategies targeting macrophages may facilitate islet xenograft survival. A role for NK cells cannot be excluded, but appears to be of minor importance.