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At least 1,747 records · Page 97Linked to original sources
PubMed1999

The effect of lactose derivatives on intestinal lactic acid bacteria.

Nine strains of lactic acid bacteria were studied for growth and fermentation end products on lactulose, lactitol, and lactobionic acid. In addition, human fecal and biopsy isolates were screened for new potential by probiotic strains utilizing lactose derivatives, and one new isolate of Lactobacillus rhamnosus was enriched. The utilization of lactose derivatives and the effect on the fermentation end products were dependent on strain. Typical mixed-acid fermentations were observed with Lb. rhamnosus and Lactococcus lactis. Microbiota enriched from fecal and biopsy samples using modified MRS medium consisted mainly of enterococci and streptococci. The adhesion of tested strains to Caco-2 cells was not dependent on carbon source. The new Lb. rhamnosus strain VTT E-97800 has potential for further probiotic studies.

Bacterial Adhesion↗
PubMed1999

[Effect of lactation state (1st-20th week of lactation) on dynamics of C-reactive protein (CRP) in initial quarter milk samples in relation to somatic cell count, lactose content and blood serum CRP levels].

The concentration of C-reactive protein (CRP) in milk and blood serum varies during the first half of lactation. Somatic cell count and lactose content also depend on the stage of lactation. CRP blood serum levels show a distinct tendency to increase from the 2nd to the 20th week of lactation. In contrary the milk CRP content decreases from the 1st week to the end of the 2nd month post partum and increases again from the 8th to the 20th week post partum. Somatic cells and CRP-concentrations in milk increase parallelly but the lactose content shows a contrary pattern in the first five months of lactation.

Animals↗
PubMed1999

[Investigations on the behavior of C-reactive protein, cell count, lactose content as well as electric conductivity in quarter milk samples of subclinically diseased quarters of the udders in relation to bacteriologic results].

Inflammations of the udder influence the amount of somatic cells and lactose as well as electrical conductivity in milk. They are often caused by bacterial agents. Similar reactions are to be seen in relation to C-reactive protein (CRP). The amount of CRP in milk depends on concentration and characteristics of the agents and the phase of inflammation. We found a significant increase of CRP in milk samples with Streptococcus (Sc.) uberis. There was no significant difference in CRP concentrations in samples with coagulase positive Staphylococcus spp. (CPS) and bacteriological negative samples and such with Corynebacterium (C.) bovis, Micrococcus spp. and Staphylococcus (S.) epidermidis. We only found high correlations to the amount of somatic sells and lactose as well as electrical conductivity in samples with Sc. uberis. The results of our investigations show that CRP may be a parameter for better understanding subclinical inflammations of udder.

Animals↗
PubMed1975

Antibody affinity. VIII. Measurement of affinity of anti-lactose antibody by fluorescence quenching with a DNP-containing ligand.

The method of fluorescence quenching by bound ligand for the measurement of antibody affinity has been extended to anti-lactose antibodies. The basis for this extension is the use of a lactosyl ligand covalently linked to the 2,4-dinitrophenyl (DNP) group. This group serves as a sensor of the bound state by causing fluorescence quenching similar to that observed with anti-DNP antibody. The synthesis and characterization of this new ligand, N-(Nalpha-acetyl,Nepsilon-DNP-L-lysyl)-rho-aminophenyl-beta-lactoside, are described. The affinity of its interaction with three rabbit IgG and one equine IgM antilactose antibody preparations has been measured. The Qmax values range from 24 to 47% and the calculated association constants from 2.5 times 10-5 M-1 to 7.2 times 10-5 M-1. For one IgG preparation, measurement of the association constant by equilibrium dialysis with the tritiated ligand gave a value of 6.75 times 10-5 M-1 compared to the value of 7.2 times 10-5 M-1 obtained by fluorescence quenching. It is evident that with monoclonal anti-lactose antibody the accurate determination of Qmax, which is possible in this system, provides another structurally dependent clonal characterization of the variable region of the antibody. This optical probe along with others can be used for the identification of individual clones of antibody-producing cells through time and inheritance.

Aminoglycosides↗
PubMed2001

Does low lactose milk powder improve the nutritional intake and nutritional status of frail older Chinese people living in nursing homes?

BACKGROUND: Malnutrition is prevalent among nursing home residents in Hong Kong. Nutrient dense oral supplements and yoghurt are unpopular among the Chinese older people because of their unfamiliar tastes and relatively high costs. Vitamin and mineral supplements do not address the problem of protein calorie undernutrition. Milk powder may be a suitable alternative supplement, but diarrhoea resulting from lactase deficiency is common in Chinese people. OBJECTIVE: We hypothesized that a low lactose milk powder would be better tolerated in Chinese nursing home residents and result in improvement in nutritional intake without reducing habitual intake. DESIGN: Forty-seven residents were randomized to receive milk powder twice daily, or no supplement for seven weeks. Twenty-four hour food record, body weight, upper limb skinfold thicknesses and midarm circumference, grip strength, Barthel Index, and abbreviated mental test score were carried out at baseline and at seven weeks. RESULTS: The overall compliance was nearly 100%, and no subjects developed diarrhoea. Compared with controls, milk supplementation increased intake of calcium, vitamin D, vitamin A, riboflavin and potassium. There was no significant reduction in habitual dietary intake in supplemented subjects. There was a trend of weight gain in supplemented subjects, though this did not reach statistical significance. There was no change in handgrip strength, mental function and disability level. CONCLUSION: The study shows that low lactose milk powder is a well-accepted nutritional supplement without reducing habitual dietary intake.

Aged↗
PubMedDate not supplied

[Analysis of a lactose tolerance test].

OBJECTIVE: The present study analyzes the Lactose Tolerance Test in order to propose a reduction in the length of it. DESIGN: Cross-sectional, descriptive study. METHODS: Glycemia curves of patients considered tolerant and intolerant were compared. Results were analyzed for 56 patients. A cost minimization analysis was performed. RESULTS: Six patients had a normal curve of tolerance and the other 50 had flat curves. Both groups had similar basal levels of glycemia 93.3 and 90.3 (p=0.1). Glycemia levels measured at 30 minutes were 122 and 86.0 (p= 0.003) and at 60 minutes 108.3 and 87.5 (p=0.02), both groups being statistically different. Values at 120 minutes were not statically different between both groups (p=0.4) and not different from basal levels. CONCLUSIONS: Diagnosis of lactose intolerance could be made using a shorter test, without considering the 120-minute figure. A 25% reduction in user s cost could be attained using the modified method as compared with the standard test.

Adult↗
PubMedDate not supplied

[The electro-optical investigation of suspensions of Escherichia coli K-12 cells metabolizing glucose, lactose, and galactose].

The electro-optical characteristics of suspensions of Escherichia coli K-12 cells metabolizing glucose, lactose, and galactose were studied my measuring the suspension turbidity as a function of cell alignment in an orienting electric field whose frequency was varied from 10 kHz to 10 MHz. In a frequency range of 10 kHz to 1 MHz, the orientational spectra of E. coli K-12 cells grown on glucose and lactose considerably changed after their incubation in the presence of the sugars. These changes likely reflect alterations in the polarizability of the cells induced by sugar metabolism.

Culture Media↗
PubMed2002

Comparison of the performance of lactose and mannitol selenite enriched broths, subcultured to DCA and XLD agars, in the isolation of Salmonella spp. from faeces.

Selenite-based enrichment broths using either lactose or mannitol as a carbohydrate source are generally used as selective enrichment media for the isolation of Salmonella spp. from human faeces in the UK, but few studies have compared the relative efficacy of the available formulations. A variety of solid media is used for the routine subculture from these selective broths, but similarly we have been unable to find published evidence as to which medium performs best. Four thousand and nineteen faecal samples were examined in four laboratories and the isolation rates of Salmonella spp. from lactose (LS) or mannitol selenite (MS) broths, plated onto either xylose lysine desoxycholate agar (XLD) or desoxycholate citrate agar (DCA) were compared. MS performed significantly better than LS (p = 0.02), recovering 95 salmonellae compared with 87. No significant difference in isolation rates was found between XLD and DCA, although colonial appearances of suspected salmonellae on XLD were much more specific, resulting in significantly fewer colonies having to be selected for supplementary testing (p < 0.001) and so reducing confirmatory work. An opportunity exists to simplify holdings of media by choosing to use the MS/XLD combination.

Bacteriological Techniques↗
PubMed1992

Lactose transport system of Streptococcus thermophilus. Functional reconstitution of the protein and characterization of the kinetic mechanism of transport.

The kinetic mechanism of the lactose transport system of Streptococcus thermophilus was studied in membrane vesicles fused with cytochrome c oxidase containing liposomes and in proteoliposomes in which cytochrome c oxidase was coreconstituted with the lactose transport protein. Selective manipulation of the components of the proton (and sodium) motive force indicated that both a membrane potential and a pH gradient could drive transport. The galactoside/proton stoichiometry was close to unity. Experiments which discriminate between the effects of internal pH and delta pH as driving force on galactoside/proton symport showed that the carrier is highly activated at alkaline internal pH values, which biases the transport system kinetically toward the pH component of the proton motive force. Galactoside efflux increased with increasing pH with a pKa of about 8, whereas galactoside exchange (and counterflow) exhibited a pH optimum around 7 with pKa values of 6 and 8, respectively. Imposition of delta pH (interior alkaline) retarded the rate of efflux at any pH value tested, whereas the rate of exchange was stimulated by an imposed delta pH at pH 5.8, not affected at pH 7.0, and inhibited at pH 8.0 and 9.0. The results have been evaluated in terms of random and ordered association/dissociation of galactoside and proton on the inner surface of the membrane. Imposition of delta psi (interior negative) decreased the rate of efflux but had no effect on the rate of exchange, indicating that the unloaded transport protein carries a net negative charge and that during exchange and counterflow the carrier recycles in the protonated form.

Bacterial Proteins↗
PubMed1992

Novobiocin-brilliant green-glycerol-lactose-agar: further routine evaluation on 5554 human stools and 982 veterinary samples.

In order to provide a wider evaluation of "Novobiocin-brilliant green-glycerol-lactose" (NBGL) agar, dishes of this medium were added to standard media: Hektoen (H), Salmonella-Shigella agar (SS), at all plating steps for 5554 stool cultures of human medical routine (280 isolates) and 982 samples of veterinary routine (133 isolates). NBGL expectedly missed lactose-glycerol positive strains of the serotype Senftenberg (n = 4), H2S negative strains (n = 1), and strains of the Typhi serotype (n = 7). Otherwise, three strains, of serotype Virchow, were unable to grow on NBGL (0.7% of positive samples). Nevertheless overall sensitivities were increased by approximately 10% in the human routine (H: 70%; SS: 63%; NBGL: 94%; at the direct plating step) (H: 83%; SS: 84%; NBGL: 92%; at the enrichment plating step) and by 48% in the veterinary one (NBGL: 97%; versus usual media: 68%). Positive predictive values of black centred colonies were significantly higher on NBGL in human routine (H: 38%; SS: 40%; NBGL: 89%; at the direct plating step) (H: 20%; SS: 21%; NBGL: 82%; at the enrichment plating step); and in the veterinary one as well (NBGL: 90%; versus usual media: 17%). These data suggest that NBGL agar does improve Salmonella isolation in these kinds of routines, and that growth should be made sure before experiments using given strains.

Animals↗
PubMedDate not supplied

[Selection and study of potent lactose-fermenting yeasts].

Whey-fermenting Kluyveromyces cultures were revealed among 105 yeast strains assimilating lactose. Eighteen most potent strains isolated from milk products fermented galactose, sucrose, and raffinose, in addition to lactose. Many yeast strains fermented inulin. Most strains were resistant to cycloheximide and grew in medium containing glucose, NaCl, and ethanol at concentrations of up to 50, 11-12, and 10-12%, respectively (4 degrees C). Three strains had mycocinogenic activity. After fermentation of whey with selected yeast strains at 30 degrees C for 2-3 days, ethanol concentration was 4-5%.

Culture Media↗
PubMed2004

[Study of the strength of compacts of mixed dry binders consisting of powdered cellulose and directly compressible lactose].

The paper studied the strength of compacts of dry binders consisting of powdered cellulose and directly compressible lactose. The powdered cellulose employed was Arbocel A300, the directly compressible lactose, Pharmatosa DCL 21. The first step of the evaluation comprised the tensile strength of compacts and sensitivity of dry binders alone to an addition of magnesium stearate. The same method of evaluation was then used for mixed dry binders from Arbocel A300 and Pharmatosa DCL 21 in ratios of 3:1, 1:1 and 1:3. The tested concentrations of magnesium stearate were 0.4 and 0.8%. Sensitivity of dry binders to an addition of the lubricant was evaluated by means of lubricant sensitivity ratio (LSR) values. The compacts with the highest strength and at the same time the lowest sensitivity to an addition of magnesium stearate were produced using a mixture of Arbocel A300 and Pharmatosa DCL 21 in a ratio of 1:3. The evaluation also included the commercially produced mixed dry binder Cellactosa 80, in which higher sensitivity to an addition of stearate than in a mixture of Arbocel A300 and Pharmatosa DCL 21 in a ratio of 1:3 was found.

Cellulose↗
PubMed2005

[Lactose-induced diarrhea increases oxidative stress and it is more severe in rats deficient in vitamin E].

Diarrhea is the disease with high incidence in the world and causes infant mortality and malnutrition in the developing world. This justifies the study of nutrition and diarrhea. Due to ethical and financial considerations it is difficult to study nutrition and diarrhea in children thus animal models have become a convenient alternative. In previous studies it was shown that lactose induced diarrhea in rats was associated with a reduction in tissue levels of vitamin E and also with evidence of an inflammatory response of the intestine. Accordingly, in this study, in order to determine the effect of this type of diarrhea on the level of oxidative stress, diarrhea was induced in vitamin E sufficient and deficient rats. The results showed that after 23 days the tissue concentration of vitamin E decreased in all the rats with diarrhea but this reduction was substantially greater in the vitamin E deficient group. Moreover, diarrhea was 60% more severe in the vitamin E deficient rats than in the vitamin E sufficient group that also had diarrhea. Both diarrhea and vitamin E deficiency altered malonaldehyde and superoxide dismutase levels in various tissues. However, the most outstanding changes associated with diarrhea were a 100% increment in plasma malonaldehyde and erythrocyte superoxide dismutase activities which were 8 to 11 times higher than those seen in the rats without diarrhea. These non-invasive changes correlated well with the severity of diarrhea. The study shows that vitamin E deficiency results in diarrheas which are more severe and that lactose induced diarrhea is associated with higher levels of oxidative stress.

Animals↗
PubMed2006

[Studies of the properties of tablets made from directly compressible starch and its mixtures with directly compressible lactose].

The paper studies the strength and disintegration time of compacts made from directly compressible Starch 1500 and its mixtures with directly compressible lactose Pharmatosa DCL 15 in different relative proportions in dependence on the added lubricant magnesium stearate and the model active ingredient ascorbic acid. The dry binders under study differ in their mechanisms of compression and thus in their sensitivity to the addition of the lubricant, which is manifested in decreased strengths of the compacts as well as the mechanism of disintegration of the compacts. The mixtures of substances under study were in the relative representations of 1:3, 1:1 and 3:1. The employed concentration of the lubricant magnesium stearate was 0.4%, that of ascorbic acid, 50%. The study has confirmed and quantitatively evaluated the sensitivity of directly compressible starch to the addition of magnesium stearate. A higher share of directly compressible lactose in the mixture decreased the sensitivity of tableting material to the addition of the lubricant and shortened disintegration time. The presence of stearate did not negatively influence disintegration time, with an exception of the mixture of Starch 1500 and Pharmatosa DCL 15 1:3. An addition of the model active ingredient ascorbic acid decreased the strength of the compacts and shortened the disintegration time in all tableting materials tested.

Lactose↗
PubMed1991

[A false positive reaction to lactose in polycarbohydrate media].

In combined media for primary identification Salmonella typhi are detectable by the lactose test only within a certain range of proteolytic activities, which fact is explained by specific features of these media. Reduced proteolytic activity and thiosulfate reductase activity in S. typhi cultures resulted in false-positive lactose test and false-positive hydrogen sulfide production test, this leading to identification of these cultures as Escherichia in accordance with the universally acknowledged classification scheme. Taking this feature into consideration, the author has additionally isolated 20 typical S. typhi strains of the 22 cultures isolated in the laboratory.

Bacteriological Techniques↗
PubMedDate not supplied

Comparative uptake of calcium from milk and a calcium-rich mineral water in lactose intolerant adults: implications for treatment of osteoporosis.

Despite the links between low calcium (Ca) intake and age-related bone loss, hypertension, and colon cancer, the majority of Western populations have average daily Ca intakes substantially below recommended daily allowances. Although dietary products are widely known as a rich and valuable source of Ca in the diet, consumption of diary products is low and has been decreasing because of perceptions of excess calories and fat in the diet, as well as taste aversions. During the last decade, a marked increase in the consumption of bottled waters has occurred. Since some of these waters are characterized by high concentrations of Ca, we have studied Ca bioavailability from a Ca-rich water, using 15 lactose intolerant male individuals as subjects, and compared such bioavailability to that from milk. We report herein that the bioavailability of Ca from the water was generally as good as or better than that from milk, a food product well known for its very high Ca bioavailability. Indeed, in eight of 15 subjects, there was a higher level of Ca absorption from mineral water than from milk; bioavailability was equal in five of 15 subjects; in contrast, in two of 15 subjects, the bioavailability of Ca absorption from milk was greater than that from the mineral water. The potential implications of this observation for the prevention and management of age-related bone loss are important for preventive medicine and indicate a new, important source of dietary Ca for lactose intolerant individuals.

Adult↗
PubMed1991

Characterization of purified, reconstituted site-directed cysteine mutants of the lactose permease of Escherichia coli.

lac permease mutated at each of the 8 cysteinyl residues in the molecule was solubilized from the membrane, purified, and reconstituted into proteoliposomes. The transport activity of proteoliposomes reconstituted with each mutant permease relative to the wild-type is virtually identical with that reported for intact cells and/or right-side-out membrane vesicles. Moreover, a double mutant containing Ser in place of both Cys148 and Cys154 exhibits significant ability to catalyze active lactose transport. The results provide strong confirmation for the contention that cysteinyl residues in lac permease do not play an important role in the transport mechanism. The effect of sulfhydryl oxidant 5-hydroxy-2-methyl-1,4-naphthoquinone on lactose transport in proteoliposomes reconstituted with wild-type or mutant permeases was also investigated, and the results indicate that inactivation is probably due to formation of a covalent adduct with Cys148 and/or Cys154 rather than disulfide formation. Thus, it seems unlikely that sulfhydryl-disulfide interconversion functions to regulate permease activity.

Amino Acid Sequence↗