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At least 901 records · Page 50Linked to original sources
PubMed2003

Evaluation and interlaboratory validation of a selective agar for phosphatidylinositol-specific phospholipase C activity using a chromogenic substrate to detect Listeria monocytogenes from foods.

Phosphatidylinositol-specific phospholipase C (PI-PLC) activity is a potential virulence factor and is exhibited only by the Listeria species Listeria monocytogenes and Listeria ivanovii. A chromogenic substrate for the direct detection of PI-PLC activity is available in a new medium (BCM L. monocytogenes plating agar). The use of a chromogenic substrate offers a mechanism with which to directly screen for L. monocytogenes and L. ivanovii other than the esculin used in Oxford (OXF) and Palcam (PAL) agars, which screen for all Listeria species. The specificity levels of BCM plating agar and of BCM confirmation and rhamnose agars were evaluated with 107 Listeria and 10 Bacillus species isolates. In addition, BCM L. monocytogenes plating agar was compared with standard Listeria selective agars (OXF and PAL agars) with regard to the recovery of L. monocytogenes from 2,000 food and environmental samples obtained from eight participating laboratories. A Listeria species was isolated from at least one of the agars in 209 analyses, and L. monocytogenes was isolated in 135 of these analyses. In 27 of the analyses in which L. monocytogenes was isolated, one or more of the selective differential agars used failed to isolate L. monocytogenes, and therefore the results of these analyses were discrepant. Relative to a reference method involving the use of all three agars (OXF, PAL, and BCM agars), the OXF-BCM, PAL-BCM, and OXF-PAL combinations had sensitivities of 99.3, 99.2, and 90.2%, respectively. In statistical analyses of the different combinations of agars, the OXF-BCM and BCM-PAL combinations were found to be superior to the OXF-PAL combination for the detection of L. monocytogenes.

Agar↗
PubMed2005

Variability of virus attachment patterns to butterhead lettuce.

Enteric viruses account for most foodborne illness in the United States. The objective of this study was to determine whether the isoelectric point (pI) of viruses such as feline calicivirus (FCV), echovirus 11, and bacteriophages phiX174 and MS2 had any effect on their attachment to butterhead lettuce. The adsorption of virus particles to the lettuce was variable. Bacteriophage MS2 was the only virus that fit the current Derjaguin-Landau-Verway-Overbeek model of virus attachment. Echovirus 11 had the highest affinity to lettuce surface. Echovirus 11 appeared to exhibit reversible attachment above its pI, whereas below its pI strong adsorption was observed. Adsorption of FCV was at its maximum above its pI. Bacteriophage phiX174 exhibited the most complex adsorption pattern, with attachment occurring only at the pH extremes (pH 3.0 and 8.0). These results suggest the current model for virus adsorption to sediment does not adequately explain the attachment of virus to lettuce. Importantly, the results indirectly suggest that current sample processing methods to recover viruses from lettuce may differentially select for the recovery of only certain virus types.

Adsorption↗
PubMedDate not supplied

Fusion in posttraumatic foot and ankle reconstruction.

Despite appropriate acute treatment, many foot and ankle injuries result in posttraumatic arthritis. Arthrodesis remains the mainstay of treatment of end-stage arthritis of the foot and ankle. An understanding of the biomechanics of the foot and ankle, particularly which joints are most responsible for optimal function of the foot, can help guide reconstructive efforts. A careful history and physical examination, appropriate radiographs, and, when necessary, differential selective anesthetic blocks help limit fusion to only those joints that are causing pain. Compression fixation, when possible, remains the treatment of choice. When bone defects are present, however, neutralization fixation may be necessary to prevent a secondary deformity that could result from impaction into a bone defect.

Ankle Injuries↗
PubMed1998

Application of the polymerase chain reaction (PCR) in the epidemiology of Entamoeba histolytica and Entamoeba dispar infections.

In this paper, we briefly summarize the latest information on the polymerase chain reaction (PCR) as an epidemiologic tool for Entamoeba histolytica and Entamoeba dispar infections. This method which employs DNA template directly extracted from formalin fixed stool specimens offers a good promise for an accurate and reliable epidemiology of the two species. The assay is, sensitive enough to detect as few as five cysts in the stool sample, rapid and selectively differentiates E. histolytica from E. dispar DNA from stool specimens without the need for prior cultivation.

Animals↗
PubMed2001

[Genetic epidemiological study of populations in three regions of Chuvashia Republic].

Comprehensive population genetic and medical genetic studies were performed in three raions (districts) of Chuvashia. The population of these districts is more than 90% Chuvash. About 70% of the families that completed reproduction had two or three children. The proportion of families with four or more children was 18%. The duration of generation was 27.6 years. The differential fertility and differential mortality indices in the Chuvash population were estimated at 0.33 and 0.076, respectively. The total index of differential selection was 0.403, which is typical of modern urbanized populations. Mean values of local inbreeding calculated from Malecot's model of isolation by distance were 0.00124 and 0.00377 for the urban and rural populations, respectively, of the districts studied. The prevalence rates of autosomal dominant (AD), autosomal recessive (AR), and X-linked diseases were found to be 0.47, 0.52, and 0.35 per 1000, respectively, in the urban population and 1.62, 1.14, and 0.31 per 1000, respectively, in the rural population. Significant correlation between the local inbreeding and prevalence rates of AD and AR diseases was found. A total of 43 AD and 43 AR diseases were identified. Some of them were not found in previous studies on other populations.

Adolescent↗
PubMed2001

Cre/loxP-based reversible immortalization of human hepatocytes.

An ideal alternative to the primary human hepatocytes for hepatocyte transplantation would be to use a clonal cell line that grows economically in culture and exhibits the characteristics of differentiated, nontransformed hepatocytes following transplantation. The purpose of the present studies was to establish a reversibly immortalized human hepatocyte cell line. Human hepatocytes were immortalized with a retroviral vector SSR#69 expressing simian virus 40 large T antigen (SV40Tag) gene flanked by a pair of loxP recombination targets. One of the resulting clones, NKNT-3, showed morphological characteristics of liver parenchymal cells and expressed the genes of differentiated liver functions. NKNT-3 cells offered unlimited availability. After an adenoviral delivery of Cre recombinase and subsequent differential selection, efficient removal of SV40Tag from NKNT-3 cells was performed. Here we represent that elimination of the retrovirally transferred SV40Tag gene can be excised by adenovirus-mediated site-specific recombination.

Cell Line↗
PubMed2001

Risk and protective factors among youth offenders.

This exploratory study examined the risk and protective factors of youth offenders and their relation to recidivism. The sample consisted of 76 male and female juvenile probationers within a large metropolitan area. Archival records on probationers provided data on prior offenses, personal characteristics, familial conditions, drug use, peer selection, school performance, role models, and activities and hobbies. It was found that protective factors, specifically personal characteristics, familial conditions, and peer selection, differentiated nonrepeat offenders and repeat offenders. The present body of findings supports the adaptive model of resiliency and reinforces the importance of enhancing protective factors in youth offenders as a means of deterring delinquent behavior.

Adolescent↗
PubMed1997

A culture medium for simultaneous counts of Streptococcus mutans and lactobacilli in saliva.

The use of a single culture medium that allows the isolation and counts of both Streptococcus mutans and lactobacilli could be of great value in microbiological diagnosis, control and evaluation of prevention programs that are nowadays employed in Odontology. To date there is no method that allows the simultaneous counts of lactobacilli and S. mutans in oral samples using a single culture medium. A single culture medium would allow for a more exact diagnosis of cariogenic risk and activity and a reduction in costs and processing time. We here in propose the selective-differential LAPTg 7% sucrose medium to differentiate oral streptococci and lactobacilli according to colony morphology and dextran production. The choice of this medium was the result of testing culture media such as MRS Agar, Elliker Agar and modified LAPTg Agar.

Agar↗
PubMedDate not supplied

[Modifying action of Saccharomyces boulardii on the biological properties of enterobacteria].

The influence of the exometabolites of the fungus S. boulardii, contained in the probiotic preparation "Enterol", on the biological properties of opportunistic and pathogenic enterobacteria of fecal microflora (inactivation of lysozyme, colicin production, hemolytic activity, antibiotic resistance) was studied. The study revealed that the supernatants of S. boulardii decreased antilysozyme activity (ALA) in lactose positive (lac+) and lactose negative (lac-) Escherichia coli and Klebsiella strains, but produced no influence on ALA in Salmonella. In response to the action of S. boulardii exometabolites colicin production in E. coli (lac+) was found to increase, while in E. coli (lac-) colicin production was suppressed. An increase in the sensitivity of lactose negative E. coli to cefazolin and cefotaxime under the action of S. boulardii supenatants was noted. The results obtained in this study show the probable mechanism of the corrective action of "Enterol" on intestinal biocenosis, which should be taken into consideration in the differentiated selection of probiotics for the treatment of intestinal dysbacteriosis.

Anti-Bacterial Agents↗
PubMed1992

Genetic heterogeneity and population structure of Gond-related tribes in the Vidarbha region of Maharashtra.

Genetic heterogeneity in nine polymorphic loci is observed among Gond-related tribes in the Vidarbha region of Maharashtra. Pardhans, with their high ABO*A2 gene frequency (4.01%), low m gene frequency (57%), high P*1 gene frequency (42.7%), and high HbS trait (31.58%), differ significantly from other tribes. Per locus average heterozygosity among the studied tribes ranged from 36.24% to 40.37%, with Pardhans being more heterozygous. Analysis by FST and the empirical relationship between average allele frequencies and the ratio of within-gene to total gene diversity show that the tribes are isolated and that differentiation among them is at an early stage and approximately in conformity with expected differentiation under genetic drift. However, distances and principal components analysis reveal that Pardhans are far removed from the other tribes and from other central Dravidian tribes. Furthermore, of the various demographic parameters estimated, the high average heterozygosity in Pardhans is significantly correlated with mean marital distance (MMD), regression of MMD on wife's age, and effective population size. There is congruence between genetic and demographic data, showing that Pardhans are distinct. This conforms with Haimendorf's (1979) contention based on cultural traits that Pardhans are Gonds by historical accident and are later migrants to the Gond area from the north. The most significant and practical observation of the present study is that migration from an originally nontribal (Pardhan) to a tribal (Gond) area and admixture lead to severe disease course, differential selection pressure, and hence highly elevated HbS trait frequency.

Blood Group Antigens↗
PubMed2003

[Clinical-functional and morphological characteristics of patients with one gallstone in the gallbladder].

Patients suffering from gallstone disease form a non-uniform group. There is variance not only in the number and localization of gallstones, but also in the clinical development of the disease (the presence or absence of typical attacks of liver colic, jaundice in the anamnesis), the condition of the contractile and concentrating functions of the gall bladder, the stone formation activity and the inflammatory component manifestation. Taking into account the anamnesis data, the functional state of the gall bladder and the stone formation activity, it seems possible to make a differentiated selection of treatment methods and techniques for a certain patient suffering from the gall-bladder disease. This approach is most suitable for patients having a single stone in the gall bladder as the approach enabling to perform organ-preserving treatment for them.

Adult↗
PubMed2003

Psorophora columbiae and Psorophora toltecum (Diptera: Culicidae) Colombian populations cannot be differentiated by isoenzymes.

Two populations of the mosquito Psorophora columbiae from the central Andean area of Colombia and one population of Ps. toltecum from the Atlantic coast of Colombia were analyzed for 11 isoenzyme markers. Psorophora columbiae and Ps. toltecum are two of the main vectors of Venezuelan equine encephalitis. We found no conspicuous genetic differences between the two species. The relatively high gene flow levels among these populations indicate that these are not two different species or that there has been recent divergence between these taxa. In addition, no global differential selection among the loci was detected, although the alpha-GDH locus showed significantly less genetic heterogeneity than the remaining loci, which could mean that homogenizing natural selection acts at this locus. No isolation by distance was detected among the populations, and a spatial population analysis showed opposite spatial trends among the 31 alleles analyzed. Multiregression analyses showed that both expected heterozygosity and the average number of alleles per locus were totally determined by three variables: altitude, temperature and size of the human population at the locality. Individually, the expected heterozygosity is more related to these three variables than to the average number of alleles.

Animals↗
PubMed2004

The Bambui health and aging study: is calibration of dietary intake necessary among older adults?

Accurate measurements of food intake in surveys are difficult to be obtained especially in the older adults. Calibration, using two instruments, has been adopted in order to improve the information. This study was carried out in a random sample of older adults (> or =60) living in a Brazilian town. Food intake was obtained by the semi-quantitative food frequency questionnaire associated with photos (SFFQ-P) and the 24 hours recall (R24) with or without food models. Statistical analysis included tests to compare averages, Pearson's correlation coefficient and multiple linear regression. For all nutrients, the average intake obtained through SFFQ-P was significantly higher compared to the obtained by the R24 (p < or =0.05). SFFQ-P correlated better with R24 with food models, which was chosen as the reference method. In the multiple linear regression, vitamin C, fatty acid, protein and zinc intakes were influenced by age, especially when such nutrients were more concentrated in food not frequently reported. For protein and zinc, the significantly interaction between age with the 24 hours recall may have happened because of a differential selection of food sources as a function of age. This fact is probable related to chewing difficulties, reduction in the income and, a diet simplification associated with less complicated preparations, such as meat. This study reinforces the need for calibration of SFFQ in nutritional surveys among older adults, especially in etiological studies where the exposure assessment has to be accurate. In this case, R24 with food models should be used as a reference method to best estimate the true intake.

Adult↗
PubMedDate not supplied

The HLA association with rheumatoid arthritis.

Rheumatoid arthritis (RA) is primarily associated with HLA-DR4 in a wide range of ethnic groups. DNA analysis of HLA-DRB1 sequences shows that a limited set of alleles are positively associated with the disease. Third hypervariable region sequences QRRAA, QKRAA and RRRAA are found in up to 85% of RA patients and may constitute the basic unit of association. Risk estimates for alleles and hypervariable regions differ between ethnic groups and subsets of patients. Severe RA and Felty's syndrome are significantly associated with DR4 Dw4 and, to a lesser extent, with DR4 Dw14. In patients the latter allele is almost exclusively found in combination with Dw4, suggesting that complementation is occurring. Critical substitutions in the peptide binding groove correlate with the presence of RA, suggesting that the disease may be driven by the presentation of specifically bound peptide and/or may be influenced by differential selection of the T cell repertoire.

Arthritis, Rheumatoid↗
PubMed2006

Application of Photoshop and Scion Image analysis to quantification of signals in histochemistry, immunocytochemistry and hybridocytochemistry.

OBJECTIVE: To describe a simple method to achieve the differential selection and subsequent quantification of the strength signal using only one section. STUDY DESIGN: Several methods for performing quantitative histochemistry, immunocytochemistry or hybridocytochemistry, without use of specific commercial image analysis systems, rely on pixel-counting algorithms, which do not provide information on the amount of chromogen present in the section. Other techniques use complex algorithms to calculate the cumulative signal strength using two consecutive sections. To separate the chromogen signal we used the "Color range" option of the Adobe Photoshop program, which provides a specific file for a particular chromogen selection that could be applied on similar sections. The measurement of the chromogen signal strength of the specific staining is achieved with the Scion Image software program. CONCLUSION: The method described in this paper can also be applied to simultaneous detection of different signals on the same section or different parameters (area of particles, number of particles, etc.) when the "Analyze particles" tool of the Scion program is used.

Animals↗
PubMed1991

Pharmacological evidence for the heterogeneity of atrial natriuretic factor-R1 receptor subtype.

The atrial natriuretic factor-R1 (ANF-R1) receptor is known to mediate the biological effects of diverse natriuretic/diuretic/vasorelaxant peptides. In order to investigate the differential selectivity of this class of receptor, we have compared its pharmacological profile for various natriuretic peptides in rat, bovine, and human kidney. In contrast to bovine and rat, human kidney glomeruli do not express significant amounts of ANF-R2 receptor. In addition, the binding of 125I-labeled rat ANF-(99-126) to the ANF-R1 receptor in human and bovine kidney glomeruli is not blocked by rat ANF-(103-123) (pK less than 6), whereas in rat kidney glomeruli this peptide displays high affinity for the ANF-R1 receptor (pK = 8.5). This observation reveals a species heterogeneity between the rat and the human and bovine kidney receptors. In addition, we have observed striking differences in the pharmacological profiles of rat papillary, bovine papillary, and human kidney glomerular receptors, which contain only the 130-kDa ANF-R1 monomer. The bovine and human profiles were similar but diverged from that of the rat. In addition to the species heterogeneity of the ANF-R1 class, we could detect a significant intraspecies heterogeneity. Two distinct profiles could be disclosed, one having high affinity for both ANF and brain natriuretic peptide (BNP) and being identified in all three species studied and the other displaying lower affinity for BNP and being found in rat and human kidneys. We also demonstrate that rat and bovine papillary ANF-R1 receptors are coupled to guanylate cyclase and that ANF and BNP could activate the enzyme with potency similar to their potency in competing for 125I-labeled rat ANF-(99-126) binding. The results presented demonstrate that the ANF-R1 receptor class can be subclassified, based on distinct pharmacological profiles, and indicate a wide diversity within the ANF-R1 receptor family.

Animals↗
PubMed1991

Regulation of human bone marrow lactoferrin and myeloperoxidase gene expression by tumor necrosis factor-alpha.

Lactoferrin (LF) and myeloperoxidase (MPO) are glycoproteins synthesized in early myeloid cells (promyelocytes, myelocytes) and stored in granules of polymorphonuclear neutrophilic granulocytes. Both proteins are involved in the host inflammatory response, and LF has been found to have myelosuppressive activity in vivo and in vitro. Little is known, however, about the regulation of their production. We investigated the stability of LF and MPO mRNA and the effects of purified recombinant human TNF-alpha on LF and MPO levels in normal human bone marrow. Low density human bone marrow cells were cultured in the presence or absence of actinomycin D (10 micrograms/ml) or TNF-alpha (200 U/ml). LF and MPO RNA levels were analyzed by Northern blots using, respectively, a 650-bp insert from the plasmid pHL41, and a 2.3-kb insert from the plasmid pMPO2 as probes. It was found that: 1) LF mRNA is a fairly stable molecule, with a half-life of between 8 and 9 h, whereas MPO is less stable, with a half-life of between 4 and 5 h; 2) TNF-alpha decreases both LF and MPO mRNA levels, an effect seen by 24 h with MPO mRNA and 48 h with LF mRNA; 3) nuclear run-on assays revealed that TNF decreases transcription of the LF gene by 70% and the MPO gene by 50%; and 4) the suppressive effect of TNF-alpha on LF and MPO mRNA levels is not due to cell killing or selective differentiation and is reversible.

Bone Marrow↗
PubMed1991

Bradykinin-stimulated inositol phosphate production in NG108-15 cells is mediated by a small population of binding sites which rapidly desensitize.

[3H]Bradykinin (BDK) binds to two distinct binding sites (P less than .01, N = 12) in NG108-15 cell membranes; (site 1: Kd1 = 3.09 x 10(-10) M, Bmax1 = 242 +/- 24 fmol/mg protein) and (site 2: Kd2 = 1.94 x 10(-8) M, Bmax2 = 491 +/- 75 fmol/mg protein). Although site 1 comprises only 33 +/- 4% (N = 12) of the total binding site population, comparison of the binding affinity and functional potency for BDK agonist analogs exhibiting differential selectivity for the two sites reveals that this high affinity site is the receptor mediating inositol monophosphate (IP) production in this cell line. BDK-stimulated IP production undergoes a very rapid (5 min) desensitization that is characterized by both a loss in agonist potency (EC50 = 3.57 x 10(-9) M vs. 1.94 x 10(-10) M in controls; P less than .001, N = 12) and a decrease in amplitude of response (fold stimulation = 1.45 +/- 0.06 vs. 1.80 +/- 0.09 in controls; P less than .01, N = 12). Only the decrease in response amplitude is attenuated by down-regulation of protein kinase C by prior long term treatment of the cells with 12-O-tetradecanoylphorbol 13-acetate (TPA), indicating an involvement of protein kinase C activation in the desensitization process. Desensitization is accompanied by down-regulation of site 1 only (Bmax1 = 71 +/- 8 fmol/mg (N = 10; P less than .001 vs. controls)); Bmax2 and the Kd for BDK at both sites remain unchanged, further supporting the contention that site 1 is the functionally relevant receptor. In contrast to the functional data, long term TPA treatment does not attenuate the receptor down-regulation, indicating that the rapid desensitization involves both receptor-related and postreceptor mechanisms. The implications of this property of the BDK receptor for analog design and receptor classification are discussed.

Animals↗