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PubMedDate not supplied

Investigation of the role of human breast milk in caries development.

PURPOSE: The objective of this study was to determine the caries-related risk associated with human breast milk (HBM). METHODS: First, the plaque pH of 18 children (12-24 months) was monitored before and after a five-minute feeding with HBM to determine the pH drop and minimum pH obtained. Second, Streptococcus sobrinus 6715 was cultured for 3 hr in HBM, and the increase in the number of colony forming units (cfus) and the culture pH was measured. Third, HBM was incubated for 24 hr with powdered enamel to determine the solubility of mineral in the absence of bacteria. Fourth, HBM was mixed with acid to determine the buffering capabilities. Finally, enamel windows were created on extracted premolar crowns (N = 33) that were colonized with Mutans Streptococci and incubated with HBM. Caries was assessed visually and radiographically for 12 weeks. RESULTS: One- and two-way ANOVAs of these five assays demonstrated that HBM did not cause a significant drop in plaque pH when compared to rinsing with water; HBM supported moderate bacterial growth; calcium and phosphate were actually deposited onto enamel powder after incubation with HBM; the buffer capacity of HBM was very poor; and HBM alone did not cause enamel decalcification even after 12 weeks exposure. However, when supplemented with 10% sucrose, HBM caused dentinal caries in 3.2 weeks. CONCLUSION: It is concluded that human breast milk is not cariogenic.

Analysis of Variance↗
PubMedDate not supplied

[Interferon induction by lacticacid bacteria in vitro and in vivo experiments].

Interferonogenic acitivity of lacticacid bacteria was studied in experiments in vitro and in vivo. It have been shown, that interferon induction depends both on strain species and on culture medium used for lactobacteria harvesting. Streptococcus thermophilus induces interferon more actively in leucocytes (in vitro)--1280 AU/ml on the bines broth medium, and less actively--320 AU/ml on fermented corn medium. Interferon induction in human leucocytes was not registered in case of L. plantarum 200 strain. In vivo experiments show that E. faecium strain and strain mixture of streptococcus termophilus are active interferon inductors. Induced interferon is recognized as alpha- and gamma-interferon, with domination of alpha-interferon.

Cells, Cultured↗
PubMed1990

[Epstein-Barr virus (EBV) infection associated with nasopharyngeal carcinoma].

Etiopathogenesis of nasopharyngeal carcinoma (NPC) is not fully understood yet. However, extensive research in this area has produced significant observations which facilitate the elucidation of the etiological factors and pathogenesis. A. Etiological Factors (a) EBV: EBV serological profiles in NPC patients, presence of EBV fingerprints in NPC tumor cells, and similar terminal repeat copies of EBV-DNA in NPC tissues strongly suggest the etiological role of EBV in NPC. (b) Genetic: Evidence supporting the genetic role in the etiology of NPC are mainly epidemiological. Although HLA studies have shown an increased relative risk in Chinese with A2, and BW 46 and in Malays with B17 and B18, the significance is not high. (c) Other environmental factors: In vitro studies have indicated the possibility of factors such as salted fish, dry fish, fermented vegetables, processed meat and some Chinese traditional herbal medicines. (d) Depressed cell-mediated immunity (CMI): While humoral antibodies to various EBV antigens are raised, the CMI seems to be lowered in NPC. It is not known, however, whether depressed CMI is the effect or the cause of NPC. B. Pathogenesis (a) Receptors for EBV: The receptors for EBV, C3d receptors, exist on cells of the basal layers which are undergoing metaplastic or hyperplastic change. These cells are close to the underlying stroma which contain the lymphocytes harbouring EBV. A pre-NPC stage of metaplasia/hyperplasia and sero epidemiological studies show raised EBV antibody titer 3-5 years before the development of NPC. (b) All NPC originate from the fossa of Rosenmüller which is a recessed depression behind the torus tubarius. This space can permit prolonged contact between environmental agents and the epithelial cells.

Antibodies, Viral↗
PubMed1989

[Caries-inducing activity of isomaltooligosugar (IMOS) in in vitro and rat experiments].

The caries-inducing activity of Isomaltooligosugar (IMOS: a isomaltose rich sugar mixture) was examined in in vitro and in vivo experiments. Strains of Streptococcus mutans MT8148R and Streptococcus sobrinus 6715 fermented IMOS and produced acids. IMOS inhibited the glucan synthesis from sucrose by glucosyltransferases from both of S. mutans and S. sobrinus. Furthermore, IMOS inhibited sucrose-dependent adherence of those mutans streptococci. IMOS was found to induce significant but minimal caries SPF Sprague-Dawley rats infected with either MT8148R and 6715. However, IMOS did not inhibit the caries which was induced by sucrose.

Animals↗
PubMed1989

[Antitumor efficacy of FK 973 on malignant glioma cells].

FK 973, a new substituted dihydrobenzoxazine, was obtained by chemical modification of a novel antibiotic which was isolated from the fermentation products of streptomyces sandaensis No. 6897. FK 973 had cytotoxic effects against in vitro cultured human and murine glioma cells. The concentration of FK 973 required to inhibit cell growth by 50% was 0.06-5 micrograms/ml, after 2-day exposure of this drug against human glioblastoma (ONS-6, 12, 23, and ONS-12/ACNU), human medulloblastoma (ONS-76, 81), human neuroblastoma (ST), and murine glioblastoma (RSV-M glioma). FK 973 showed antitumor efficacy in the meningeal gliomatosis models by RSV-M glioma cells. The median survival time (MST) of models treated by FK 973 (i.t.) was 30 days. However, the MST of control group was 23 days. In the in vitro neurotoxicity test, FK 973 proved to be slightly more toxic than ACNU and MTX, but it had no crucial problems, compared with ADM.

Animals↗
PubMed1997

Short-chain fatty acid-initiated cell cycle arrest and apoptosis of colonic epithelial cells is linked to mitochondrial function.

Butyrate, a short-chain fatty acid produced during microbial fermentation of fiber, induces growth arrest, differentiation, and apoptosis of colonic epithelial cells in vitro, and our prior work has shown that this induction is tightly linked to mitochondrial activity. Here we demonstrate that 12 h following induction, SW620 human colonic carcinoma cells accumulate simultaneously in G0-G1 and G2-M of the cell cycle. Four h later, during this G0-G1 to G2-M arrest, cells begin to undergo apoptosis. Using a series of unrelated agents that modulate mitochondrial functions, we demonstrate that mitochondrial electron transport and membrane potential are critical in initiation of this butyrate-mediated growth arrest and apoptosis. Colonic tumorigenesis is characterized by abnormalities in proliferation, apoptosis, and mitochondrial activities. Thus, butyrate may reduce risk for colon cancer by inducing a pathway that enhances mitochondrial function, ultimately resulting in initiation of growth arrest and apoptosis of colonic epithelial cells.

Apoptosis↗
PubMed1990

Alanine protects rabbit proximal tubules against anoxic injury in vitro.

Rabbit proximal tubules were incubated aerobically or subjected to anoxia for 30 min followed by 60 min of reoxygenation. The medium contained (in mM) 5 glucose, 10 butyrate, 4 lactate or alpha-ketoglutarate (alpha-KG), and 1 alanine. Anoxic tubules in this medium were severely injured and recovered poorly. If the incubation medium was supplemented with additional alanine (up to 2.5 or 5 mM), then anoxic injury was prevented almost completely. Tubules in high-alanine medium showed modest elevations of ATP during anoxia. Comparable elevations of ATP were induced in anoxic tubules incubated with 4 mM alpha-KG and 5 mM aspartate without alanine. These substrates are metabolized anaerobically in the mitochondria to yield ATP. Surprisingly, anoxic tubules with alpha-KG and aspartate showed severe injury despite elevated ATP. If 5 mM alanine was also present, then additional increments of ATP did not occur, but injury was prevented. Examination of glucose metabolism failed to provide evidence for stimulation of anaerobic fermentations by alanine. These results suggest that alanine-induced cytoprotection during anoxia occurs by mechanisms not related to ATP synthesis, and that elevated ATP in alanine-supplemented tubules may be a result and not the cause of protection. Cytoprotection by alanine was shown to last for less than or equal to 90 min of anoxia. Glycine, a structurally related amino acid, also protects anoxic proximal tubules (J. Clin. Invest. 80: 1446, 1987). The mechanisms that underlie the cytoprotective effects of alanine and glycine remain to be determined.

Adenosine Triphosphate↗
PubMed1991

Fermentable carbohydrate reaching the colon after ingestion of oats in humans.

A simulated digestion technique was used to investigate the characteristics of starch hydrolysis in uncooked, cooked and extrusion-cooked oat products in vitro. The rate and extent of starch hydrolysis were both significantly lower in uncooked rolled oats than in the same material after brief boiling or extrusion cooking. A similar degree of maldigestion in vivo would lead to as much as an estimated 68% of oat starch entering the colon. Breath-hydrogen measurements were used to compare the fermentable carbohydrate content of uncooked and briefly boiled rolled oats in human volunteers and to estimate the relative contributions of soluble dietary fiber and undigested starch to the fermented component. Isolated oat gum (beta-glucan) was readily fermented in vivo and was apparently the main fermentable component of cooked rolled oats. Uncooked rolled oats gave a higher excess hydrogen production than cooked oats, but the results were variable and the differences not statistically significant. In an additional experiment, lactulose was used as a fermentable reference material to calculate the apparent fermentable carbohydrate content of rolled oats and oat gum. Uncooked rolled oats were estimated to contain a statistically significant quantity of undigested starch, amounting at most to 1.01 +/- 0.40 g (mean +/- SEM) of undigested starch per 50 g of fresh weight. We concluded that starch hydrolysis in oats is limited to some extent by the physical state of the food matrix, but this effect may be greatly overestimated by simulated digestion procedures in vitro.

Adult↗
PubMed1980

Effects of monensin and amicloral on rumen fermentation.

Fermentative adjustments produced by monensin and amicloral and by combinations of monensin plus amicloral were investigated in vitro. Monensin increased (P < .05) production of propionate, usually decreased production of acetate and butyrate and partially reduced methanogenesis, but no accumulation of gaseous hydrogen was observed. Amicloral not only increased production of propionate (P < .05), but also usually increased butyrate production, decreased (P < .05) acetate production and almost completely inhibited (P < .05) methanogenesis, and substantial quantities (P < .05) of hydrogen accumulated in the gas phase. Both chemical agents were effective (P < .05) in decreasing utilization of an exogenous amino acid load. Monensin plus amicloral produced fermentative adjustments comparable to those predicted from cultures medicated with monensin or amicloral alone; thus, effects mediated by the combined agents were additive and no consistent positive or negative synergestic activities were noted. Characteristic adjustments in rumen fermentation caused by monensin, by amicloral and by additivity of these adjustments are reflections of the two chemical agents manipulating ruminal reactions by different mechanisms.

Animals↗
PubMed1999

Comparison of starch digestibility of a blended food prepared with and without extrusion cooking.

OBJECTIVE: To compare starch digestibility from a maize-soy blended food with and without extrusion cooking. DESIGN: Resistant starch, soluble and insoluble dietary fibres were measured in vitro before and after extrusion. Starch digestibility was assessed in 8 volunteers who took, in a randomised order, a test meal with either 100 g extruded (EF) or non-extruded (NEF) blended flour cooked 15 min at 80 degrees C in 500 ml of water. SETTING: Research ward for healthy volunteers. SUBJECTS: Healthy volunteers. MAIN OUTCOME MEASURES: Starch digestibility was measured by 13C enrichment of breath samples for 8 h. Breath H2 concentration was measured during 12 h to assess bacterial fermentation in the colon. Volunteers reported hunger on a visual scale every hour for 8 h. RESULTS: In vitro resistant starch, soluble and insoluble dietary fibers were higher in NEF than in EF (5.4 vs 1.1, 0.7 vs 0.5, and 13.3 vs 10.4% dw respectively). In vivo, the area under curve (AUC) for 13CO2 excretion during 8 h was not significantly different for NEF and EF (10.3+/-1.3 vs 9.1+/-0.5 mmol/min, respectively). AUC for H2 excretion during 12 h was significantly higher for EF than for NEF (26.9+/-5.6 vs 14.1+/-4.7 mL, P<0.05). AUC for satiety was marginally higher with EF (12.6+/-1.6) than for NEF (10.0+/-2.1) (P=0.06). CONCLUSIONS: Extrusion cooking does not seem to substantially improve blended foods digestibility. Extrusion of high fibre flours may promote carbohydrate fermentation in the colon and increase satiety.

Adult↗
PubMed1986

In vivo and in vitro anticancer activity of the structurally novel and highly potent antibiotic CI-940 and its hydroxy analog (PD 114,721).

CI-940, PD 114,721, and PD 118,607 are structurally novel antibiotics, which were isolated from fermentation beers of a previously unknown actinomycete. They are highly lipophilic acids characterized by unsaturated lactone and branched, polyunsaturated aliphatic side-chain moieties. All three agents demonstrated significant cytotoxic activity in vitro against a number of human and mouse tumor lines which encompassed a wide range of tissue types. CI-940 retained full activity in vitro against lines of P388 leukemia that are resistant to Adriamycin, amsacrine, and mitoxantrone. Activity was confirmed for both CI-940 and PD 114,721 against a number of murine experimental tumor systems in vivo, which included the P388 and L1210 leukemias and also B16 melanoma, Ridgway osteogenic and M5076 sarcomas, and mammary adenocarcinoma 16/C. PD 118,607 was also highly active against B16 melanoma. All three agents demonstrated anticancer activity at very low dosages compared with current clinically useful anticancer agents. No significant activity was seen against the MX-1 human mammary xenograft or pancreas 02 tumor models. The primary target for host toxicity of CI-940 and PD 114,721 appeared to be gastrointestinal in nature. Neither CI-940 nor PD 114,721 caused delayed lethality when given either IP or IV. In schedule studies, the toxicities of both CI-940 and PD 114,721 were moderately dependent on the regimen used, with total maximum tolerated dosages for intermittent (q4dx2), daily (qdx5), and divided daily (q4hx3, qdx5) dosing schedules of 1, 0.25, and 0.12 mg/kg, respectively. CI-940 is being developed for clinical trial on the basis of its potent activity against seven different tumor models, its novel structure, and its apparently novel mechanism of action.

Animals↗
PubMed2000

Binding of aflatoxin B1 to bifidobacteria in vitro.

Aflatoxins are mycotoxins that cause health and economic problems when they contaminate food and feed. One potential method for reducing human health effects due to aflatoxin ingestion is to block uptake via binding by bacteria that either make up the normal gut flora or are present in fermented foods in our diet. These bacteria would bind aflatoxin and make it unavailable for absorption in the intestinal tract. Bifidobacteria comprise a large fraction of the normal gut flora, are thought to provide many probiotic effects and are increasingly used in fermented dairy products. These qualities targeted bifidobacteria for studies to determine if various strains of heat-killed bifidobacteria can bind aflatoxin B1 (AFB1) in vitro. The AFB1 binding affinities of various strains of bifidobacteria, Staphylococcus aureus, and Escherichia coli were quantitated utilizing enzyme-linked immunosorbent and [3H]AFB1 binding assays. The bacteria analyzed were found to bind significant quantities of AFB1 ranging from 25% to nearly 60% of the added toxin. The data also suggest that there are reproducible strain differences in AFB1 binding capacity.

Aflatoxin B1↗
PubMed1998

Phenotypic and genotypic characterization of virulent yersinia enterocolitica strains unable to ferment sucrose.

Several atypical sucrose-negative Yersinia strains, isolated from clinical samples and sometimes associated with symptoms, proved to have full virulence potential in in vitro and in vivo testings. DNA-relatedness studies revealed that they were authentic Yersinia enterocolitica strains. Therefore, atypical sucrose-negative Yersinia isolates should be analyzed for their virulence potential.

Adult↗
PubMed1985

Effect of additive on alfalfa silage fermentation characteristics and feedlot performance of steers.

In each of two trials four large plastic bags were filled with approximately 72 mt of first cutting, early bloom alfalfa (35% dry matter). Fresh alfalfa in two bags was treated with .5 kg/metric ton of a commercial silage additive (Silo-Best). Two bags were left untreated. When compared with steers fed untreated alfalfa silage, weight gains, intakes, and feed efficiencies were not significantly (P greater than .05) altered for steers fed treated silage. However, laboratory analysis showed silage treatment increased in vitro dry matter digestibility (57.0 versus 60.6%) and decreased silage pH (4.98 versus 4.83). Concentrations of propionic and butyric acid were decreased by the additive. Data suggest that anaerobic fermentation was enhanced with the additive. Slight but significant improvements of silage in vitro dry matter digestibility, obtained by treating alfalfa silage with the inoculant-type preservative, did not result in improved performance in feeding trials.

Animal Feed↗
PubMedDate not supplied

Ferric nitrilotriacetate induced DNA and protein damage: inhibitory effect of a fermented papaya preparation.

The carcinogen Fe-NTA catalyzes the hydrogen peroxide-derived production of free radicals and possibly acts through a mechanism involving oxidative stress. Fermented papaya preparation (FPP) has been reported as a natural antioxidant able to prevent lipid peroxidation in vitro and in vivo. However, little is known about the antioxidant properties of FPP regarding iron-mediated oxidative damage to DNA and proteins. In the present study FPP protected supercoiled plasmid DNA against Fe-NTA plus H2O2 induced single and double strand breaks. Similar protective effects of FPP were evident when human T-lymphocytes were challenged with Fe-NTA/H2O2 and DNA damage was determined using the Comet assay. Fe-NTA/H2O2 also induced fragmentation of bovine serum albumin (BSA) in vitro and depleted cellular GSH levels in lymphocytes. BSA fragmentation and GSH depletion were dose-dependently counteracted by FPP. EPR spin trapping studies demonstrated that antioxidant properties of FPP are related to both hydroxyl scavenging as well as iron chelating properties.

Animals↗
PubMed2003

The effect of increasing copper content in phosphate-based glasses on biofilms of Streptococcus sanguis.

This paper reports the effect of a series of phosphate-based glasses based on the Na(2)O-CaO-P(2)O(5) system doped with increasing amounts of copper and the effect of this increasing copper content on the viability of an in vitro biofilm of Streptococcus sanguis over an 8 day period in a constant depth film fermenter. The addition of copper to the glass caused the solubility to change, so the glasses were adjusted in order that their solubility in artificial saliva was nominally the same (0.3062 +/- 0.07 mg cm(-2) h(-1)). Initial experiments on glasses with 1.5% and 10% copper showed that after 6 h there was no statistical difference between the copper containing glasses and the non-copper containing glass and HA in terms of the viability of the biofilms. However, at 24 h there was an approximately 0.8-0.9 log reduction in viability of the biofilms grown on the 5% copper glass and an approximately 1.0-1.3 log reduction for the 10% copper containing glass. Further experiments on the glass with 10% copper and another glass with 15% copper were carried out in a time dependent study. For both glasses a clear decrease in viable counts at 24 h was found but for both glasses these returned to levels similar to those of controls. The initial decrease in viability during the first 24 h is likely to be due to the antibacterial effect of the copper and this could be correlated with copper content. The recovery after 24 h is probably due to the dead cells forming a barrier, making diffusion of the antibacterial ions, increasingly difficult. This study has shown that phosphate-based glasses could potentially be used to deliver antibacterial ions to help combat oral infections. Copper, which has been shown to have antibacterial properties, could be incorporated but some development of the glasses used in this investigation may be required. Further work is needed to determine the effectiveness of copper containing glasses on oral bacterial communities.

Anti-Bacterial Agents↗
PubMed1976

Effects of crp mutations on adenosine 3',5'-monophosphate metabolism in Salmonella typhimurium.

Wild-type Salmonella typhimurium could not grow with exogenous cyclic adenosine 3',5'-monophosphate (AMP) as the sole source of phosphate, but mutants capable of cyclic AMP utilization could be isolated provided the parental strain contained a functional cyclic AMP phosphodiesterase.All cyclic AMP-utilizing mutants had the growth and fermentation properties of cyclic AMP receptor protein (crp) mutants, and some lacked cyclic AMP binding activity in vitro. The genetic defect in each such mutant was due to a single point mutation, which was co-transducible with cysG. crp mutants isolated by alternative procedures also exhibited the capacity to utilize cyclic AMP. crp mutants synthesized cyclic AMP at increased rates and contained enhanced cellular cyclic AMP levels relative to the parental strains, regardless of whether or not cyclic AMP phosphodiesterase was active. Moreover, adenylate cyclase activity in vivo was less sensitive to regulation by glucose, possibly because the enzyme II complexes of the phosphotransferase system, responsible for glucose transport and phosphorylation, could not be induced to maximal levels. This possibility was strengthened by the observation that enzyme II activity (measured both in vitro by sugar phosphorylation and in vivo by sugar transport and chemotaxis) was inducible in the parental strain but not in crp mutants. The results suggest that the cyclic AMP receptor protein regulates cyclic AMP metabolism as well as catabolic enzyme synthesis.

3',5'-Cyclic-AMP Phosphodiesterases↗