Bacterial community profiles of endodontic abscesses from Brazilian and USA subjects as compared by denaturing gradient gel electrophoresis analysis

This study compared the bacterial community profiles of the microbiota associated with acute apical abscesses from Brazilian and USA patients using denaturing gradient gel electrophoresis (DGGE). DNA was extracted from purulent exudate aspirates and part of the 16S rRNA gene was amplified by polymerase chain reaction and separated by DGGE. The resulting banding patterns, which were representative of the bacterial community structures in samples from the two locations, were then compared. Distinct DGGE banding patterns were observed from different samples. Ninety-nine bands with distinct positions in the gels were detected, of which 27 were found only in the USA samples and 13 were exclusive to Brazilian samples. Four of the 59 shared bands showed very discrepant findings with regard to prevalence in the two locations. Cluster analysis of DGGE banding profiles showed a great variability in the bacterial populations associated with teeth with abscesses regardless of the geographical location. Two big clusters, one for each location, were observed. Other clusters contained a mixture of samples from the two locations. The results of the present study demonstrated a great variability in the bacterial community profiles among samples. This indicates that the bacterial communities of abscesses are unique for each individual in terms of diversity. The composition of the microbiota in some samples showed a geography-related pattern. Furthermore, several bands were exclusive for each location and others were shared by the two locations and showed great differences in prevalence.

Functional significance of hsp90 complexes with NOS and sGC in endothelial cells

Although the existence of hsp90-NOS and hsp90-sGC complexes is now firmly established, their role in many pathophysiological processes remain unclear. These complexes may represent physiological mechanisms aimed at maximizing intracellular cGMP production in response to endogenous or drug-derived NO in endothelial cells and thus affecting permeability, proliferation, migration and apoptosis. Along with minimizing NO scavenging by superoxide and reducing the formation of peroxynitrite, these complexes may also prolong sGC stability by retarding its degradation. Our work and that of others have demonstrated that, depending on the environment, sGC interaction with hsp90 can optimize sGC enzyme activity or modulate sGC survival. This review addresses the functional significance of hsp90 complexes with NOS (eNOS, iNOS) and sGC in endothelial cells relevant for maintaining endothelial barrier integrity and angiogenesis. Structural and functional characteristics of sGC, its expression, transcriptional and post-translational regulation, as they relate to sGC-hsp90 interactions, will also be examined.

Cloning, chromosomal localization and expression patterns of porcine Kruppel-like factors 4, -5, -7 and the early growth response factor 2

Kruppel-like factors (KLF) and the early growth response factor 2 (EGR2) are important zinc finger transcription factors in vertebrates. We have cloned the full length coding sequence (CDS) of porcine KLF5, KLF7 and EGR2, which are 1374, 909 and 1416 bp, respectively. KLF4, KLF5 and EGR2 were then chromosomally mapped to porcine 1q28-29, 11q13-14 and 14q23-25, respectively. Moreover, the tissue expression patterns of KLF4, KLF5, KLF7 and EGR2 imply their probable roles in specific tissues. This is the first report of the basic study of these zinc finger transcription factors in pigs; this information will be helpful for future functional studies.

Cloning, chromosome mapping and expression characteristics of porcine ANGPTL3 and -4

Angiopoietin-like protein 3 and -4 (ANGPTL3 and -4) are two members of angiopoietin-like proteins (ANGPTLs), which have the signature structure of the angiopoietin family but cannot bind to the TIE2 receptor. It has been reported that they both affect lipid metabolism by inhibiting the activity of lipoprotein lipase (LPL). Here we report the cDNA cloning, chromosome mapping and expression analysis of ANGPTL3 and -4 in pigs. Sequence analysis shows that ANGPTL3 contains an open reading frame of 1,389 bp, which encodes 462 amino acids, and ANGPTL4 contains a coding region of 1,239 bp, which encodes 412 amino acids. Porcine ANGPTL3 deduced amino acid sequence shares 83% and 73.7% identity with human and mouse, respectively, and ANGPTL4 shares 79.4% and 77.7% amino acid identity with human and mouse, respectively. Porcine ANGPTL3 and -4 were mapped to the 6q31-->q35 and 2q21-->q24 region, respectively, by radiation hybrid mapping. Tissue distribution analysis indicated that porcine ANGPTL3 mRNA was exclusively expressed in liver, and porcine ANGPTL4 was ubiquitously expressed with the highest abundance in white adipose tissue. Furthermore, the mRNA level of ANGPTL3 and -4 in liver and the mRNA level of ANGPTL4 in white adipose tissue were significantly higher in genetically obese pigs than in their lean counterparts. This is the first report of molecular cloning and characterization of ANGPTL3 and -4 in pigs, which will be helpful for a better understanding of the role of ANGPTLs in lipid metabolism.

Cloning, expression and chromosome localization of porcine adiponectin and adiponectin receptors genes

Adiponectin is a cytokine secreted specifically by adipocytes that has been proposed to enhance insulin sensitivity and prevent atherosclerosis. Adiponectin receptors (adipoR1 and adipoR2) are recently found in mice which act as receptors for globular and full-length adiponectin to mediate the fatty-acid oxidation and glucose uptake in muscle and liver. The primary goal of this study was to examine chromosome localization of porcine adiponectin and adiponectin receptors and the gene expression pattern in various tissues of pigs of the three genes. Radiation hybrid mapping demonstrated that porcine adiponectin, adipoR1 and adipoR2 were located to chromosome13q36-41, 10p11 and 5q25, in the regions that were syntenic to the homologs of human genes, respectively. Semi-quantitative RT-PCR showed that porcine adiponectin mRNA was specifically expressed in adipose tissue and porcine adipoR1 and adipoR2 mRNA were ubiquitously expressed in many tissues except brain. Comparison to adipoR2 mRNA which was highly expressed in liver, heart, kidney, adipose tissues and lung, adipoR1 mRNA was expressed at relatively high levels in porcine muscle, leukocytes and epididymis. Our data provide basic molecular information useful for the further investigation on the function of the three genes.

Cloning and characterization of porcine resistin gene

Resistin is a member of resistin-like molecules (RELMs) and a hormone secreted from mature adipocytes in rodents and leukocytes in human. We now report the cloning and characterization of the full-length porcine resistin cDNA and gene. Sequence analysis indicated that the pig resistin cDNA sequence had an open reading frame of 330 bp encoding a 12 kDa protein of 109 amino acids. The deduced amino acid sequence showed 75.2% identity to the human resistin. The porcine resistin gene was composed of four exons and had exactly the same exon structure as the human resistin gene. The tissue distribution of porcine resistin mRNA was assessed by semi-quantitative RT-PCR. Resistin gene expression was the highest in porcine leukocytes and low in adipose tissue. Resistin protein could be detected in porcine serum by western blotting and it circulated in serum as dimers and trimers. We provided the first evidence that resistin was abundantly expressed in porcine leukocytes and had an expression pattern similar to that in human resistin mRNA and protein. This suggests that the pig may be a suitable animal model for studying the function of resistin in human insulin resistance.

Searching for Archaea in infections of endodontic origin

Archaea is a highly diverse group of prokaryotes, whose members have been traditionally recognized as extremophiles. Recently, some of these microorganisms have also been found to thrive in nonextreme environments, including the human body. Methanogenic archaea have been detected in samples from subgingival plaque associated with periodontal disease and a pathogenetic role is suspected. The purpose of this study was to survey samples taken from different types of endodontic infections for the presence of archaea. Samples were taken from untreated and treated root canals associated with asymptomatic chronic periradicular lesions as well as from cases diagnosed as acute periradicular abscesses. Overall, 96 samples were obtained. DNA from samples was extracted by using two different protocols and used as template for polymerase chain reaction amplification using oligonucleotide universal primers for the domains Archaea or Bacteria. Samples were also checked for the presence of spirochetes by making use of a group-specific primer. While bacteria were present in all samples, no case yielded archaeal DNA. Spirochetes occurred in a high number of cases. Our findings suggested that members of the Archaea domain are not members of the microbiota present in different types of endodontic infections and thereby may not be implicated in the etiology of apical periodontitis.

Effects on protein and mRNA expression levels of p53 induced by fluoride in human embryonic hepatocytes

We investigated the effects of protein and mRNA expression levels on p53 induced by fluoride in human embryo hepatocyte L-02 cells. The protein and mRNA levels of p53 in L-02 cells were measured after in vitro cultured L-02 was exposed to sodium fluoride at different doses (40, 80, and 160 microg/ml) for 24 h. The results showed that the cell survival rate of L-02 cells in the high dose fluoride group was significantly lower than that of the control group. The protein expression levels of p53 in the middle and high dose fluoride group were significantly higher than in the control group and elevated with increasing fluoride concentration. The mRNA expression levels of p53 in the fluoride groups were markedly higher than in the control group. The mRNA expression level of p53 in the high dose fluoride group was however lower compared to the middle dose fluoride group, but similar to the low dose fluoride group. These finding suggest that fluoride can decrease the L-02 cells survival rate and induce protein and mRNA expressions of p53; however, there is no consistency between the protein expression level of p53 and the mRNA expression level.

Effects of phenobarbital on metabolism and toxicity of diclofenac sodium in rat hepatocytes in vitro

Diclofenac sodium (DF-Na) was a nonsteroidal anti-inflammatory drug used in various aspects of inflammatory disease. The purpose of this study was to examine the effects of phenobarbital (PB) on metabolism and toxicity of DF-Na in vitro and explore the potential mechanism of DF-Na induced hepatotoxicity. Rat hepatocytes were isolated by a modification of the two-step in situ collagenase perfusion technique and the harvested rat hepatocytes were cultured with sandwich method. Control or PB (2 mM) pre-treated hepatocytes were incubated with DF-Na (0.1, 0.05 or 0.01 mM) in vitro and cytosolic enzyme leakage levels, cytochrome P450 (CYP) 3A activity, and metabolite content of DF-Na in cell culture medium were measured. The results showed that without any treatment hepatocyte CYP 3A activity gradually decreased with culture time. On day four, CYP 3A activity was 53% of the initial value. The decline of CYP 3A was partially reversed by CYP inducer PB, and the maximum induction of CYP 3A was 2.2-fold over control after continuous exposure of hepatocytes to 2 mM PB for 48 h. Lactic dehydrogenase (LDH), aspartate transaminase (AST), and alanine transamine (ALT) activity and the contents of the DF-Na metabolites 4'-hydroxydiclofenac (4'-OH-DF) and 5-hydroxydiclofenac (5-OH-DF) in media appeared to increase with increasing DF-Na concentrations, though there were no significant differences between DF-Na exposed and control hepatocytes. However, if the hepatocytes first were pre-treated with 2 mM PB for 2 days and then exposed to DF-Na, the concentrations of DF-Na metabolites and the activity of LDH in the media were significantly higher than that of control group. These findings suggest that the hepatotoxicity and metabolism of DF-Na in rat hepatocytes are increased when hepatic CYP 3A activity is increased.

Increased expression of resistin and tumour necrosis factor-alpha in pig adipose tissue as well as effect of feeding treatment on resistin and cAMP pathway

AIM

Resistin, a novel hormone, is expressed in mouse, rat and human adipose tissue. Its resistance to insulin is controversial. We hypothesized that resistin has the similar roles like those of tumour necrosis factor-alpha (TNF-alpha), a putative mediator of insulin resistance, and they are in common involved in regulating lipid metabolism in vivo.

METHODS

We demonstrated TNF-alpha and resistin expression in different growth-stage adipose tissue of genetically lean and obese pigs using semiquantitative reverse transcriptase-polymerase chain reaction and Western blotting analysis. Moreover, we analysed the variations of resistin and some parameters associated with lipolysis pathway after body-weight reduction in feeding-restricted obese pigs. In addition, we localized resistin expression in the cell types from pig adipose tissue.

RESULTS

Overall, the expression of TNF-alpha and resistin in obese pigs was statistically higher than their lean counterparts, although this difference in resistin mRNA expression tailed off with age. In individual pigs, their levels increased progressively with age and degree of obesity. After feeding restriction, resistin expression was gradually decreased. Simultaneously, feeding restriction also resulted in a significant decrease of serum triglyceride and plasma cAMP, free fatty acids and insulin as well as fat adenyl cyclase and cAMP. In addition, in isolated pig adipocytes, our data showed that resistin was localized not only to adipocytes but also to other unidentified stromal vascular cells.

CONCLUSIONS

TNF-alpha and resistin are increased in obesity. Weight loss results in the decrease of resistin and lipolysis-associated parameters, suggesting the possible association between resistin and lipolysis pathway. Cell localization of resistin expression implies the possibility of other biological actions of resistin.

Stage-specific expression of leukaemia inhibitory factor and its receptor in rabbit pre-implantation embryo and uterine epithelium during early pregnancy

Leukaemia inhibitory factor (LIF) has been shown to play an important role in the development and implantation of blastocysts in mice. In the current study, the reverse transcription-polymerase chain reaction (RT-PCR) was employed to examine the expression patterns of LIF and its receptor (LIFR) genes in rabbit embryos during pre-implantation development, and the uterine expression of LIF and LIFR was also evaluated by Western blotting. Transcripts for LIFR were detected within morula and blastocyst-stage embryos, while the LIF mRNA was only found in blastocysts (from early to fully expanded blastocoel cavities), indicating that embryo-derived LIF can act in an autocrine manner on the process of blastocyst formation. The expression levels of LIF and LIFR in uterine epithelium were gradually increased during pre-implantation period and reached their highest levels on days 6.5 of pregnancy, just before the time of blastocyst implantation, suggest that paracrine LIF circuit should exist between the endometrium and the early embryos, which may be involved in the embryo-maternal dialogue and important for the blastocyst implantation. The data present here show the stage-specific and dynamic expression patterns of LIF and LIFR, both in embryos and endometrium, during early pregnancy in rabbits, which indicated that LIF might play an important role in the pre-implantation development and subsequent implantation of rabbit embryos.

Geographical Differences in Bacteria Detected in Endodontic Infections Using Polymerase Chain Reaction

The polymerase chain reaction (PCR) is an innovative nucleic acid-based assay that has the highest sensitivity of any microbiological technique for the detection of bacteria. The purpose of this study was to use PCR to detect the presence of specific species of bacteria in samples collected from two geographical locations. Microbial samples from abscesses of endodontic origin were collected from patients in Portland, Oregon, and Rio de Janeiro, Brazil. PCRs with species-specific oligonucleotide primers for the 16S ribosomal RNA gene were used for detection of the bacteria after DNA extraction from each clinical sample. Statistical analysis revealed that there was a significant difference in detection of the bacteria between the two geographical locations for Prevotella intermedia, Prevotella nigrescens, Prevotella tannerae, Fusobacterium nucleatum, and Porphyromonas gingivalis, but not for Porphyromonas endodontalis, Fusobacterium necrophorum, and Enterococcus faecalis. These results suggest that differences in bacteria detected or cultured in studies can be associated with geographical location.

[TFAR19 enhances the opening of permeability transition pore in the mitochondrial membrane of mice liver]

TFAR19 TF-1 cell apoptosis related gene 19 is a novel apoptosis-related gene cloned from human leukemia cell line TF-1 cells undergoing apoptosis in 1999 (accession number AF014955 in GenBank). The human TFAR19 encodes a protein which shares significant homology to the corresponding proteins of species ranging from yeast to mice. TFAR19 exhibits a ubiquitous expression pattern and its expression is upregulated in tumor cells undergoing apoptosis. Overexpression of TFAR19 could enhance apoptosis of some tumor cells induced by growth factor withdrawal or serum deprivation. But the exact mechanism of TFAR19 is unclear. Mitochondria not only provides energy for the cell, but also plays a critical role on cell death or survival. The release of apoptosis promoting factor, such as cytochrome c from mitochondria, resulted by the damage of mitochondrial membrane integrity, is the key factor controlling apoptosis. The permeability transition pore (PTP) of mitochondria is a protein complex located between the mitochondrial membranes, and it plays an important role in regulating the integrity of mitochondrial membrane. In this study, the effect of recombinant TFAR19 on isolated mitochondrial PTP, membrane potential, and release of cytochrome c was investigated in vitro. The results indicated that recombinant TFAR19 facilitated the isolated mitochondrial PTP opening, decreased the membrane potential, and promoted the release of cytochrome c. The effect of TFAR19 on mitochondria is implemented by opening the mitochondrial PTP. Experimental results implicate that TFAR19 may positively feedback apoptosis signal of mitochondria, forming a positive loop to promote apoptosis.

Large libraries reveal diverse solutions to an RNA recognition problem

RNA loops that adopt a characteristic GNRA "tetraloop" fold are common in natural RNAs. Here, we have used in vitro selection by means of mRNA-peptide fusions to select peptides that bind an example of this RNA loop motif. Starting with the RNA recognition domain from the lambda N protein, we have constructed libraries containing 150, 1,600, and 9 trillion different peptide sequences as mRNA-peptide fusions and isolated those capable of high-affinity RNA binding. These selections have resulted in more than 80 different peptides that bind the same RNA loop. The highest affinity peptides exhibit low nanomolar dissociation constants as well as the ability to discriminate RNA hairpins differing by a single loop nucleotide. Thus, our work demonstrates that numerous, chemically distinct solutions exist for a particular RNA recognition problem.

[Studies on the hydroxyl free radical-scavenging effect of combined selenium and germanium]

The effect of selenium, carboxyethyl-germanium sesquioxide (Ge-132) and the combination of selenium and Ge-132 on the production of hydroxyl free radical in liver microsomes of rats treated with Fe2SO4-NADPH system was studied with electron spin resonance technique (ESR). The results showed that the production of hydroxyl free radical was decreased significantly by adding selenium, Ge-132 and combined selenium and Ge-132, indicating a direct scavenging effect on hydroxyl free radical. It was also observed a enhanced scavenging effect at the low concentration of combined selenium and Ge-132.

Relationship between thermal parameters and tumor response in hyperthermia combined with radiation therapy

BACKGROUND

In hyperthermia for cancer therapy, thermal parameters related to tumor response have not yet been clarified. We investigated thermal parameters that could predict tumor response to hyperthermia combined with radiotherapy in locally advanced malignancies.

METHODS

Fifty-four patients with locally advanced malignancies who were treated by hyperthermia in combination with radiation therapy were enrolled in this study. Local hyperthermia was induced by ultrasound heating equipment for 60 min, within 30 min after irradiation, twice a week, for a total of six to ten sessions. Radiation therapy was administered with a conventional fractionation regimen, at a total dose of 40-70 Gy. Multi-point thermometry results were obtained with every 10-s temperature data acquisition. An average of seven interstitial sites per tumor was monitored for each treatment. Univariate logistic regression analysis was used to investigate the relationship between tumor response and minimum, maximum, and average intratumor temperature (Tmin, Tmax, Tav); the cumulative minutes of treatment at temperatures exceeded by 90%, 50%, and 10% of the measured intratumoral temperatures (T90, T50, T10); and cumulative minutes of the temperature that achieved above the index temperature value in the tumor center ((Cum min T(center) > T(index)).

RESULTS

Complete and partial response rates were 32.6% and 46.2%, respectively. Univariate logistic regression analysis revealed that the temperature parameters with predictive probability were highest for Cum min T(center) > 42.5 degrees C, followed by > 42 degrees C and > 41 degrees C; and T90. Cum min T(center) > 42.5 degrees C was most significantly associated with complete tumor response (P < 0.001).

CONCLUSION

These results strongly suggest that hyperthermia is a useful adjunct to radiotherapy for increasing the local control of advanced malignancies, and that Cum min T(center) > 42.5 degrees C could be an important thermal parameter for predicting tumor response.

Isolation and characterization of a Na+/H+ antiporter gene from the halophyte Atriplex gmelini

With a homologous gene region we successfully isolated a Na+/H+ antiporter gene from a halophytic plant, Atriplex gmelini, and named it AgNHX1. The isolated cDNA is 2607 bp in length and contains one open reading frame, which comprises 555 amino acid residues with a predicted molecular mass of 61.9 kDa. The amino acid sequence of the AgNHX1 gene showed more than 75% identity with those of the previously isolated NHX1 genes from glycophytes, Arabidopsis thaliana and Oryza sativa. The migration pattern of AgNHX1 was shown to correlate with H+-pyrophosphatase and not with P-type H+-ATPase, suggesting the localization of AgNHX1 in a vacuolar membrane. Induction of the AgNHX1 gene was observed by salt stress at both mRNA and protein levels. The expression of the AgNHX1 gene in the yeast mutant, which lacks the vacuolar-type Na+/H+ antiporter gene (NHX1) and has poor viability under the high-salt conditions, showed partial complementation of the NHX1 functions. These results suggest the important role of the AgNHX1 products for salt tolerance.