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PubMed1996

Effects of different types of dietary fiber preparations isolated from bamboo shoots, edible burdock, apple and corn on fecal steroid profiles of rats.

This study was conducted to evaluate the effects of different types of dietary fibers (DF) under the conditions with or without cholesterol (Chol) loading on the amount and composition of steroids in rat feces. Rats were fed Chol-unsupplied diets containing 10% lard and 5% DF preparation isolated from four kinds of food, bamboo shoots, edible burdock, apple and corn, for three weeks. The respective diets were supplemented with 0.5% Chol and then given to the rats for a further two weeks. The excretion of total bile acid (BA) and several major BAs increased significantly in the apple group with or without Chol loading when compared with that in the cellulose (CP) or other DF groups. The tendency in the apple group was more noticeable when the diet was supplemented with Chol. This is presumably a major reason for the tendency of decrease in serum and liver Chol concentrations in the apple group. The ratio of secondary BAs to total BA in the feces was significantly low in the apple group. Although the lithocholic acid (LCA)/deoxycholic acid (DCA) ratio, a risk index for colorectal cancer, was significantly lower in the bamboo, burdock and apple groups than in the CP or corn groups when given the diet without Chol, the differences disappeared with the addition of Chol. The proportion of coprostanol, a secondary metabolite of Chol, was smaller in the former three groups than in the CP or corn groups. These results suggest that the intake of some DF by host animals works beneficially for the microbial conversion of BA and Chol in the large intestine but that the addition of Chol acts to cancel such beneficial effects.

Animal Feed↗

PubMed2003

Ozonation of an azo dye C.I. Remazol Black 5 and toxicological assessment of its oxidation products.

The effect of ozonation (20.5 mgl(-1)) on the degradation processes of an azo dye, Remazol Black 5 (RB5; CI) was studied. Conventional parameters such as chemical oxygen demand (COD), total organic carbon (TOC), pH, conductivity, colour removal, biodegradability (BOD(5/28)), and toxic potential of the dye and its degradation products were monitored during the process. The results obtained indicated that ozonation is a highly effective way to remove the colour of a corresponding dye solution. However, a considerable organic load still remained as indicated by high COD and TOC residues. The COD, TOC reductions were about 40% and 25% for 6 h ozonation of 2 gl(-1) RB5 aqueous solution. During the ozonation process the rapid decrease of pH and the sharp increase of conductivity indicated the formation of acidic by-products and small fragments and ions which were identified by high performance ion chromatography. The BOD28 data revealed that first by-products after partial ozonation (10-150 min) of RB5 were more biodegradable than the parent compound and ozonation can enhance the biodegradability of azo dyes. During the first 150 min of total 360 min of oxidation, the formation of first by-products with high toxic potential took place as it could be confirmed by two acute toxicity-screening tests, the bioluminescence test (Vibrio fischerii) and the neutral red cytotoxicity assay (rat hepatoma cells). The significant enhancement of microbial biodegradability after long-term ozonation could also be seen as a decrease of toxic intermediates in correlation with the ozonation time as indicated in BOD28 biological degradation test results.

Animals↗

PubMed2001

Impact of baseline polymorphisms in RT and protease on outcome of highly active antiretroviral therapy in HIV-1-infected African patients.

OBJECTIVE: To assess the therapeutic response and investigate the significance of polymorphic codons in African patients receiving highly-active antiretroviral therapy (HAART). DESIGN AND METHODS: African patients were identified from the St Mary's Hospital HIV-1 database. Clinical outcome was assessed by viral load and CD4 cell count. Pre- and post-therapy sequences of RT and protease were analysed. The impact of subtype and individual polymorphic codons on therapeutic outcome was assessed statistically (Fishers exact and chi2 tests) and phylogenetically (Jukes and Cantor). RESULTS: Of 79 drug-naive African patients who were prescribed HAART, 60 remained undetectable for 1 year, with no differences detected in the clinical response to non-nucleoside reverse transcriptase inhibitor (NNRTI)- or protease inhibitor (PI)-containing regimes. Country of origin, sex and viral subtype had no impact on outcome of HAART. A total of 133 polymorphisms were identified in pol (37 in protease and 96 in RT), with a mean of 9.0 in protease and 22.3 in RT per patient. There was no significant difference in the overall numbers of polymorphisms per patient, and no single polymorphism had any impact on clinical outcome. Sequences from 'failing' patients experiencing viral rebound produced few mutations known to be associated with drug resistance, suggesting minimal drug pressure. CONCLUSIONS: The response of patients infected with African subtypes of HIV-1 to HAART appears to be independent of regime, HIV-1 clade and baseline polymorphisms. Non-B subtypes are fully sensitive to HAART and, accordingly, therapy should not be withheld from African patients for reasons of viral diversity.

Africa↗

PubMed1991

Reduction of salivary bacteria by pre-procedural rinses with chlorhexidine 0.12%.

The purpose of this study was to assess the effect of pre-procedural rinsing (2 consecutive rinses) with 0.12% chlorhexidine gluconate (CHX) on salivary bacteria during scaling and root planing procedures (S&RP). Because blood and debris arising from S&RP could inactivate CHX and decrease its antimicrobial effect, patients were evaluated throughout their appointment. Forty subjects rinsed with either 15 ml of CHX rinse or control (sterile water) for 30 seconds, expectorated and immediately rinsed again for 30 seconds. Unstimulated saliva samples were obtained at baseline (immediately before rinsing), and at 1 minute, 30 minutes, and 60 minutes after baseline. All 30 and 60 minute samples contained visible blood and debris. Samples were immediately diluted in transport fluid containing a CHX-neutralizer and then plated on trypticase soy agar for enumeration of the total aerobic and facultative bacterial load. The dual rinses with 0.12% CHX immediately reduced the salivary bacterial load 97% and this reduction persisted for 60 minutes during S&RP. At 30 minutes and at 60 minutes aerobic bacteria were reduced 77% compared to control, and 96% compared to baseline. CHX was not inactivated by the high organic load (blood and debris) present during the procedure. Pre-procedural rinsing with CHX has a profound and sustained effect on the aerobic and facultative flora of the oral cavity, which may contribute to a variety of clinical benefits. Pre-procedural rinsing may also be of value in protecting patients and dental professionals during dental manipulations.

Adult↗

PubMed1982

Microbiological studies on hamburgers.

One hundred and eighty-two raw, 112 pre-cooked and 750 cooked hamburgers composed mainly of beef or beef and pork were subjected to microbiological examination.Raw hamburgers gave total bacterial counts from 10(6) to 10(8) per g, counts of Enterobacteriaceae from 10(4) to 10(6) per g, of Escherichia coli from 10(3) to 10(5), of group D streptococci from 10(2) to 10(4), of Staphylococcus aureus from 3 to 10(2) and of Clostridium perfringens less than 10 bacteria per g. Of the samples, 32% contained salmonellas; the highest most probable number was 10(2) per g but most estimates were below 1 per g. Corresponding figures for the pre-cooked samples were 2-3 log cycles lower, and only one sample contained salmonella. Yersinia enterocolitica was not isolated from any raw or pre-cooked sample.Three hundred and ninety-five of the cooked hamburgers were prepared by grilling raw hamburgers for between 2 and 5.5 min. These gave total bacterial counts from 10(5) to 10(7) per g, and counts of Enterobacteriaceae from 10(2) to 10(5) per g. Of the samples, 9.4% contained salmonellas, always in numbers below 1 per g. The remaining 355 cooked hamburgers were prepared from samples pre-cooked for 10 min at 80 degrees C. Some were grilled and some fat fried. The total bacterial counts were from 10(3) to 10(5) per g, and counts of Enterobacteriaceae below 10(2) per g. Salmonellae, again in small numbers only, were recovered from 3.5% of samples.When hamburgers were artificially contaminated with Salmonella typhimurium it took 5.5 min on a commercial grill, 2.25 min frying in a frying pan and 1.75 min on a household grill to reliably reduce the salmonella count one hundredfold. This means that at many vending places hamburgers are often cooked for too short a time.D-values were determined for S. typhimurium in hamburger meat at 50, 55, 60, 65 and 70 degrees C, these values were 7.1, 5.1, 1.2, 0.9 and 0.6 min respectively. It can be concluded that the heating action in the centre of the hamburgers will take place more slowly than in the hamburger as a whole, and that the time between cooking and consumption is very important in reducing the microbial load to acceptable levels.Pre-cooking (10 min at 80 degrees C in a water bath) gives a reduction in the numbers of salmonella of about 4 x 10(3), after which cooking gives a further reduction as mentioned above.

Animals↗

PubMed1993

Effect of treated-sewage contamination upon bacterial energy charge, adenine nucleotides, and DNA content in a sandy aquifer on Cape Cod.

Changes in adenylate energy charge (ECA) and in total adenine nucleotides (A(T) and DNA content (both normalized to the abundance of free-living, groundwater bacteria) in response to carbon loading were determined for a laboratory-grown culture and for a contaminated aquifer. The latter study involved a 3-km-long transect through a contaminant plume resulting from continued on-land discharge of secondary sewage to a shallow, sandy aquifer on Cape Cod, Mass. With the exception of the most contaminated groundwater immediately downgradient from the contaminant source, DNA and adenylate levels correlated strongly with bacterial abundance and decreased exponentially with increasing distance downgradient. ECAS (0.53 to 0.60) and the ratios of ATP to DNA (0.001 to 0.003) were consistently low, suggesting that the unattached bacteria in this groundwater study are metabolically stressed, despite any eutrophication that might have occurred. Elevated ECAS (up to 0.74) were observed in glucose-amended groundwater, confirming that the metabolic state of this microbial community could be altered. In general, per-bacterium DNA and ATP contents were approximately twofold higher in the plume than in surrounding groundwater, although ECA and per-bacterium levels of A(T) differed little in the plume and the surrounding uncontaminated groundwater. However, per-bacterium levels of DNA and A(T) varied six- and threefold, respectively, during a 6-h period of decreasing growth rate for an unidentified pseudomonad isolated from contaminated groundwater and grown in batch culture.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenine Nucleotides↗

PubMed2005

Transport of chemical and microbial compounds from known wastewater discharges: potential for use as indicators of human fecal contamination.

The quality of drinking and recreational water is currently (2005) determined using indicator bacteria. However, the culture tests used to analyze forthese bacteria require a long time to complete and do not discriminate between human and animal fecal material sources. One complementary approach is to use chemicals found in human wastewater, which would have the advantages of (1) potentially shorter analysis times than the bacterial culture tests and (2) being selected for human-source specificity. At 10 locations, water samples were collected upstream and at two successive points downstream from a wastewaster treatment plant (WWTP); a treated effluent sample was also collected at each WWTP. This sampling plan was used to determine the persistence of a chemically diverse suite of emerging contaminants in streams. Samples were also collected at two reference locations assumed to have minimal human impacts. Of the 110 chemical analytes investigated in this project, 78 were detected at least once. The number of compounds in a given sample ranged from 3 at a reference location to 50 in a WWTP effluent sample. The total analyte load at each location varied from 0.018 microg/L at the reference location to 97.7 microg/L in a separate WWTP effluent sample. Although most of the compound concentrations were in the range of 0.01-1.0 microg/L, in some samples, individual concentrations were in the range of 5-38 microg/L. The concentrations of the majority of the chemicals present in the samples generally followed the expected trend: they were either nonexistent or at trace levels in the upstream samples, had their maximum concentrations in the WWTP effluent samples, and then declined in the two downstream samples. This research suggests that selected chemicals are useful as tracers of human wastewater discharge.

Bacteria↗

PubMed1998

Treatment of vascular graft infection by in situ replacement with cryopreserved aortic allografts: an experimental study.

PURPOSE: The purposes of this study were to prove the efficacy of cryopreserved aortic allografts to treat an established vascular graft infection by in situ replacement in an animal model and to evaluate the role of the antibiotics normally used to decontaminate the allografts. METHODS: Twenty-three dogs underwent infrarenal aortic replacement with a gelatin-sealed knitted polyester graft contaminated in vitro by Staphylococcus epidermidis RP-62. One week later, the 18 surviving animals underwent reoperation for graft removal and were randomized into three groups for in situ replacement: group I (control, n = 6) received a new gelatin-sealed graft; group II (n = 6) received a non-antibiotic-treated cryopreserved allograft; and group III (n = 6) received an antibiotic-treated cryopreserved allograft. Control grafts and allografts were removed 4 weeks after the initial intervention for quantitative bacteriologic analysis and histologic analysis. Bacteriologic results were expressed as colony-forming units per square centimeter of graft material. Qualitative bacteriologic analysis was also obtained from perigraft fluid and tissue. RESULTS: All of the initially implanted grafts and all of the control grafts (group I) were infected at the time of removal. In group II, three out of six allografts were not totally incorporated, whereas in group III incorporation was always complete, with a significantly decreased inflammatory reaction. All of the antibiotic-treated allografts were sterile, whereas three untreated allografts grew bacteria. CONCLUSIONS: In this model, cryopreserved aortic allografts were more resistant to reinfection than synthetic grafts after in situ replacement of an infected prosthetic graft. However, the antibiotic loading of the cryopreserved aortic allograft appears to be essential to obtain optimal therapeutic effects.

Animals↗

PubMed2004

Inhibition of C5 or absence of C6 protects from sepsis mortality.

Inhibiting complement anaphlytoxin C5a during sepsis may prevent sepsis mortality. Although human anti-C5 antibodies exist, their therapeutic use in microbial sepsis has been avoided because of the hypothesis that inhibiting C5b will prevent formation of the bactericidal membrane attack complex (MAC) and worsen clinical outcome. We wished to test the hypothesis that inhibition of C5 would improve outcomes in sepsis. Sepsis was induced in rats by laparotomy and cecal ligation and puncture (CLP) by an IACUC-approved protocol. Sham animals underwent laparotomy without CLP. Following CLP rats were randomized to receive a single IV dose of purified IgG ant-C5 antibody (Ab) or control IgG Ab. Anti-C5 Ab treated rats (n = 20) had significantly lower mortality vs. controls (n = 21), 20% vs. 52% (P = 0.019, log-rank). Analysis of bacterial load by culture of spleen and liver homogenates showed a reduction in colony forming units in anti-C5 Ab treated rats vs. control IgG (P = 0.003 and 0.009, respectively). Anti-C5 treatment reduced lung injury as measured by total MPO content of lung tissue (P = 0.024). Finally, rats genetically deficient in C6 production, unable to form MAC but capable of producing C5a and C5b, were protected from CLP-induced sepsis mortality. Our results show that in anti-C5 antibody therapy prevents CLP sepsis-induced mortality and improves lung injury. Inhibition of the complement MAC does not increase bacterial load or mortality, therefore, the use of anti-C5 therapy may be beneficial rather than detrimental in sepsis.

Animals↗

PubMed1996

Effect of pre-slaughter washing of lambs on the microbiological and visible contamination of the carcases.

Studies in four slaughterhouses with contrasting dressing systems showed that microbiological contamination with total aerobic bacteria and Escherichia coli was greater on carcases which had been washed before slaughter, irrespective of wool length, and was generally higher on carcases derived from woolly lambs than on those derived from shorn lambs. The effects of pre-slaughter washing on the forequarters compared with the hindquarters were not consistent, and this was attributed to differences between the dressing systems applied in the slaughterhouses. Over all trials the mean total aerobic count ranged from 3.45 to 5.36 log10/cm2, and the mean counts of E coli ranged from 0.39 to 2.11 log10/cm2. There was less visible contamination on the carcases of washed lambs than on those of unwashed lambs. The differences in contamination with wool were largely dependent on the level of contamination of individual carcases, whereas the differences in contamination with faecal material and dirt or sand were largely dependent on the prevalence of affected carcases. The use of pre-slaughter washing to compensate in visual terms for poor pre-slaughter presentation results in a detrimental effect on microbiological loads on ovine carcases.

Abattoirs↗

PubMed1994

Subgingival bacteria in a case of prepubertal periodontitis, before and one year after extractions of the affected primary teeth.

The treatment of children with prepubertal periodontitis (PP), may be complicated by the extent of the lesions and the possibility of tetracycline stain of the developing permanent dentition. Therefore, with the purpose of preventing the infection of permanent teeth during the mixed dentition, it has been recommended that the treatment of children with PP, should include the early extraction of the primary teeth affected with alveolar bone loss (ABL). Still, there is little evidence which confirms that extraction of the affected primary teeth do in fact reduce the periodonto-pathogens load of the subgingival plaque. The present study reports values of colony forming units (CFU) of total anaerobic bacteria, Actinobacillus actynomicetemcomitans (Aa) and Porphyromonas gingivalis (Pg) from the subgingival plaque from a child with PP, collected immediately before and 1 year after extractions of the primary teeth affected with ABL. CFU of Aa and Pg developed only from the subgingival plaque collected before the extraction of the primary teeth affected with ABL. These findings suggest that in cases of PP, extraction of the affected primary teeth may reduce the possibility of infection of the periodontum of the permanent teeth during the mixed dentition period.

Aggregatibacter actinomycetemcomitans↗

PubMed2007

Long-term performance of peat biofilters treating ethyl acetate, toluene, and its mixture in air.

Three laboratory-scale peat biofilters were operated at 90 s empty bed residence time (EBRT) for over a year. Biodegradation of ethyl acetate, toluene, or a 1:1 mixture were investigated. In first stage, inlet concentration was progressively increased from 0.4 to 4.5 g/m(3). The maximum elimination capacity (EC) found for ethyl acetate was 190 gC/m(3).h, and it was not affected by toluene. The maximum EC found for toluene as a sole contaminant was 150 gC/m(3).h, but the presence of ethyl acetate decreased the toluene maximum EC to 80 gC/m(3).h. From respirometry monitoring, values of 3.19 g CO(2)/gC and 3.06 g CO(2)/gC for pure ethyl acetate and pure toluene, respectively, were found, with overall yield coefficients of 0.13 g dry biomass produced per gram ethyl acetate consumed and 0.28 g dry biomass produced per gram toluene consumed. CO(2) production in the 1:1 mixture was successfully simulated. Dynamics of living and dead cells were monitored in four sections of the biofilters. Concentrations ranged between 2.6 x 10(9) and 3.0 x 10(10) cells per gram-dry peat for total bacteria, and 2.4 x 10(9)-1.9 x 10(10) cells per gram-dry peat for living bacteria. At high loads loss of bacterial density in the inlet zones, and increase in the dead cells percentages up to 60% was observed. In second stage, long-term performance at an inlet concentration of 1.5 g/m(3) was evaluated to show the process feasibility. Good agreement with previous data was obtained in terms of EC and CO(2) production. Restoration of living cells proportion was also observed.

Acetates↗

PubMed2003

Fungal load and candidiasis in Sjögren's syndrome.

OBJECTIVE: We sought to investigate the prevalence of Candida carriage and the relationships between salivary flow rates and oral Candida load in patients with Sjögren's syndrome (SS). METHODS: The oral Candida load of patients with SS was evaluated by culturing oral rinse (swish and spit) samples. Culture, Gram stain, and wet-mount test results were reported. RESULTS: One hundred three patients (96 women) met European criteria for SS (91 with primary SS and 12 with secondary SS). The mean age (95% confidence interval) was 55 years (range, 51-57 years). Oral rinse cultures were positive in 77% of subjects. The total stimulated salivary flow rate was inversely correlated with oral Candida load (r = -0.47; P </=.0001). The oral rinse samples yielded gram-positive results in 38% of patients with SS, and the Fungi-Fluor assay (wet mount) results were positive in 49%. CONCLUSIONS: The prevalence of Candida carriage varies according to the methods used to determine the presence of the organism and is similar to that reported in the literature. A low stimulated salivary flow rate-not a low unstimulated flow rate-was associated with Candida carriage.

Candida↗

PubMed1998

Continuous alcoholic fermentation of glucose/xylose mixtures by co-immobilized Saccharomyces cerevisiae and Candida shehatae.

Viable Saccharomyces cerevisiae and Candida shehatae cells were co-immobilized in a composite agar layer/microporous membrane structure. This immobilized-cell structure was placed in a vertical position between the two halves of a double-chambered, stainless-steel bioreactor of original design and applied to the continuous alcoholic fermentation of a mixture of glucose (35 g dm-3) and xylose (15 g dm-3). Various dilution rates and initial cell loadings of the gel layer were tested. Simultaneous consumption of the two sugars was always observed. The best fermentation performance was obtained at low dilution rate (0.02 h-1) with an excess of C. shehatae over S. cerevisiae in the initial cell loading of the gel (5.0 mg dry weight and 0.65 mg dry weight cm-3 gel respectively): 100% of glucose and 73% of xylose were consumed with an ethanol yield coefficient of 0.48 g g total sugars-1. In these conditions, however, the ethanol production rate per unit volume of gel remained low (0.37 g h-1 dm-3). Viable cell counts in gel samples after incubation highlighted significant heterogeneities in the spatial distribution of the two yeast species in both the vertical and the transverse directions. In particular, the overall cell number decreased from the bottom to the top of the agar sheet, which may explain the low ethanol productivity relative to the total gel volume.

Bioreactors↗

PubMed2004

Nitric oxide exerts distinct effects in local and systemic infections with Streptococcus pneumoniae.

Nitric oxide (NO) is known to be involved in the immune response against a range of organisms. Little is known about the effects of nitric oxide in pneumococcal infections. We have now investigated the role of nitric oxide in local and systemic infections caused by Streptococcus pneumoniae in NOS2 deficient mice. Although a deficiency in NO does not affect survival of mice during pneumococcal pneumonia, NO does control pneumococcal viability within the lung airways and tissue. Bronchoalveolar lavage fluid (BALF) from NOS2-deficient mice contained significantly elevated TNF activity, IFNgamma and total protein during mid/late infection. Incubation of S. pneumoniae with the NO donor SNAP revealed a direct anti-pneumococcal effect for NO in vitro. Deficiency in NOS2 did not affect bacteraemia following intranasal infection. In contrast NOS2-deficient mice were significantly less susceptible to intravenous infection with S. pneumoniae than were wild type mice and were able to control pneumococcal viability within the bloodstream. Our results indicate that NO is required within the lungs for anti-bacterial activity during the pneumococcal pneumonia but during Gram-positive bacteraemia NO is associated with increased bacterial loads and reduced survival.

Animals↗

PubMed2005

Antibacterial properties of Ag nanoparticle loaded multilayers and formation of magnetically directed antibacterial microparticles.

Antibacterial coatings based on hydrogen-bonded multilayers containing in situ synthesized Ag nanoparticles were created on planar surfaces and on magnetic colloidal particles. We report the antibacterial properties of these coatings, determined using a disk-diffusion (Kirby-Bauer) test, as a function of the film thickness and the concentration of Ag nanoparticles in the hydrogen-bonded multilayers. The zone of inhibition (ZoI) determined by the disk-diffusion test increases as the thickness of the multilayer film is increased. Results obtained for the values of the ZoI as a function of film thickness can be described adequately with a simple diffusion model (i.e., the square of the zone of inhibition (ZoI) depended linearly on the logarithm of the thickness of the silver-loaded films). This observation suggests that, in order to incrementally increase the ZoI, an exponentially increasing amount of Ag is required within the multilayers. In general, there was no statistically significant correlation between the zone of inhibition and the number of Ag loading and reduction cycles. The duration of sustained release of antibacterial Ag ions from these coatings, however, could be prolonged by increasing the total supply of zerovalent silver in the films via multiple loading and reduction cycles. These results indicate that the release of silver is controlled by an oxidation mechanism at the surface of the nanoparticles and that repeated loading and reduction of silver leads preferentially to growth of the existing silver nanoparticles in the film as opposed to nucleation of new Ag nanoparticles. We also show that magnetic microspheres coated with silver nanoparticle loaded hydrogen-bonded multilayer thin films can be used to deliver antibacterial agents to specific locations. The minimum inhibitory concentration (MIC) of nanocomposite coated microspheres was determined by the agar dilution technique: antibacterial magnetic microspheres with higher concentrations of Ag nanoparticles exhibited lower MIC values.

Acrylic Resins↗

PubMed1997

Line probe assay for rapid detection of drug-selected mutations in the human immunodeficiency virus type 1 reverse transcriptase gene.

Upon prolonged treatment with various antiretroviral nucleoside analogs such as 3'-azido-3'-deoxythymidine, 2',3'-dideoxyinosine, 2',3'-dideoxycytidine, (-)- beta-L-2', 3'dideoxy-3'thiacytidine and 2',3'-didehydro-3'-deoxythymidine, selection of human immunodeficiency virus type 1 (HIV-1) strains with mutations in the reverse transcriptase (RT) gene has been reported. We designed a reverse hybridization line probe assay (LiPA) for the rapid and simultaneous characterization of the following variations in the RT gene: M41 or L41; T69, N69, A69, or D69; K70 or R70; L74 or V74; V75 or T75; M184, I184, or V184; T215, Y215, or F215; and K219, Q219, or E219. Nucleotide polymorphisms for codon L41 (TTG or CTG), T69 (ACT or ACA), V75 (GTA or GTG), T215 (ACC or ACT), and Y215 (TAC or TAT) could be detected. In addition to the codons mentioned above, several third-letter polymorphisms in the direct vicinity of the target codons (E40, E42, K43, K73, D76, Q182, Y183, D185, G213, F214, and L214) were found, and specific probes were selected. In total, 48 probes were designed and applied to the LiPA test strips and optimized with a well-characterized and representative reference panel. Plasma samples from 358 HIV-infected patients were analyzed with all 48 probes. The amino acid profiles could be deduced by LiPA hybridization in an average of 92.7% of the samples for each individual codon. When combined with changes in viral load and CD4+ T-cell count, this LiPA approach proved to be useful in studying genetic resistance in follow-up samples from antiretroviral agent-treated HIV-1-infected individuals.

Acquired Immunodeficiency Syndrome↗

PubMed1999

Enhancement of butyrate production in the rat caecocolonic tract by long-term ingestion of resistant potato starch.

Some data suggest that the colonic microflora may adapt to produce more butyrate if given time and the proper substrate. To test this hypothesis, we investigated the effect of prolonged feeding of resistant potato starch on butyrate production. Rats were fed on either a low-fibre diet (basal) or the same diet supplemented with 90 g resistant potato starch/kg (PoS) for 0.5, 2 and 6 months. Short-chain fatty acid (SCFA) concentrations were determined in caecal and colonic contents at the end of each ingestion period. Total SCFA concentration increased over time throughout the caecocolonic tract with PoS, but was not modified with the basal diet. While propionate concentration was unchanged, butyrate concentration was highly increased by PoS at each time period in both the caecum and colon. Moreover, the butyrogenic effect of PoS increased over time, and the amount of butyrate was increased 6-fold in the caecum and proximal colon and 3-fold in the distal colon after 6 months compared with 0.5 months. Accordingly, the ratio butyrate:- total SCFA increased over time throughout the caecocolonic tract (12.6 (SE 2.8) v. 28 (SE 1.8)% in the caecum, 10.5 (SE 1.4) v. 26.8 (SE 0.9)% in the proximal colon, and 7.3 (SE 2.4) v. 23.9 (SE 2.7)% in the distal colon at 0.5 v. 6 months respectively), while the proportion of acetate decreased. Neither the proportion nor the concentration of butyrate was modified over time with the basal diet. Butyrate production was thus promoted by long-term ingestion of PoS, from the caecum towards the distal colon, which suggests that a slow adaptive process occurs within the digestive tract in response to a chronic load of indigestible carbohydrates.

Animals↗