Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “LACTOSE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources
PubMed2004

[Influence of live flora on lactose digestion in male adult lactose-malabsorbers after dairy products intake].

OBJECTIVE: To evaluate the effect of live flora on lactose absorption in male adult lactose-malabsorbers. METHODS: After giving consents, 45 health male adult volunteers were challenged with 20 g lactose in 200 ml water in the morning without breakfast. The expired samples of breath were collected at every 30 min point in 3 hours. 24 persons were chosen as subjects (lactose-malabsorbers) when their expired H2 of any time point was 30 micromol/mol more than the baseline, and divided into 3 groups randomly. The test dairy were yogurt (Y) and heat-treated yogurt (HY), and acidified gelled milk (M), all containing 20 g lactose. The study was double blind, randomized and 3 x 3 latin square design. Three group subjects ingested the 3 different dairy products in 3 different days. The washout time was 7 days. After drinking each dairy in the morning without breakfast, the expired samples at every 30 min were collected during 8 hours test time with no food and no violent exercise. Hydrogen concentration of expired sample was detected by gas chromatography. RESULTS: The peak hydrogen concentration (Cmax) of yogurt is significant less than heat-treated yogurt and milk (Y 113.2 +/- 70.2, HY 186.5 +/- 96.7, M 174.7 +/- 73.9). The peak time of Cmax (Tmax) of yogurt is significant more than milk (Y 390 +/- 86, M 305 +/- 105). The area under the hydrogen concentration curve (AUC) of yogurt is significant less than the other two dairy products (Y 14,900.1 +/- 12,206.2, HY 27,389.5 +/- 20,429.8, M 25,648.2 +/- 14,064.0). CONCLUSION: The live flora in dairy product could improve lactose digestion in male adult lactose malabsorbers.

Adult↗
PubMed1995

Assessment of optimal dose of lactose for lactose hydrogen breath test in Indian adults.

To evaluate the possibility of using a 12.5 g or 25 g oral dose of lactose for hydrogen breath test for diagnosis of lactose intolerance instead of the usual 50 g dose. 35 patients with non-ulcer dyspepsia and an abnormal 50 g lactose breath hydrogen of more than 20 ppm over the base line were retested using 12.5 g and 25 g lactose. 32 (91.4%) and 15 (42.8%) of these 35 patients had an abnormal hydrogen breath test using 25 g (p = ns compared to 50 g dose) and 12.5 g (p < 0.001) lactose doses respectively. This study reveals that it may be possible to use a 25 g lactose dose instead of a 50 g dose for the lactose hydrogen breath test.

Breath Tests↗
PubMed1991

[Lactose--a potential dietary fiber. The regulation of its microecologic effect in the intestinal tract. 4. Dietary fiber action of lactose: evaluation with multivariate statistical analysis].

The conditions and the intestinal processes responsible for the action of lactose as a potential dietary fibre are described. The beta-galactosidase activity in the rat caecum and colon is influenced by dietary factors: It declines with increasing lactose concentration and it rises with increasing protein and phosphate concentration in the diet. The enzyme activity correlates negatively with the content of lactose, and positively with the content of protein and phosphate in the chymus. The products of lactose hydrolysis are degraded by microbial glycolysis in caecum and colon. The glycolytic products are mainly absorbed and energetically utilized by the macroorganism. Phosphate stimulates the microbial metabolism and, therefore, accelerates the consumption of the energy substrate lactose. Mathematical optimization gives the necessary composition of the diet which causes an intended microecological effect. To minimize the chymus pH (5.1 in the colon ascendens; 4.6 in the colon descendens; 4.3 in the faeces) the lactose content of the diet has to be greater than or equal to 160 mumol/g, the protein content less than or equal to 10 mg/g, and the phosphate content less than or equal to 5.5 mumol/g. The minimal pH value depends to a greater extent on variations in the supply of protein and phosphorus with the diet whereas the response to changes in lactose concentration is less noticeable.

Animals↗
PubMed1980

Effects of lactose and mode of sterilization of a lactose diet on mineral metabolism in germ-free and conventional rats.

Mineral balances of Ca, P, Mg, K, Na, Zn, Mn, Cu were carried out on 6-week old Fisher rats for 14 consecutive days. Four lots of germfree (GF) and 4 lots of conventional (CV) rats were fed a semi-synthetic diet at weaning containing either 0 or 10 p. 100 of lactose (L). The diet was sterilized either by irradiation (I) or by autoclave (Au). Lactose, when added to the diet, caused very variable modifications of the mineral metabolism, depending on the mineral studied and the mode of sterilization. Thus, retention and apparent absorption of iron were hardly changed by the presence of lactose. On the other hand, those of Mn were strongly enhanced by the lactose. The action of the other minerals was complex; it was modulated either by the mode of diet sterilization, the flora, or by both factors simultaneously. The IL diet increased retention of most of the minerals; in some cases (Na, Zn, P, Ca) it was only evidenced in CV rats; in other cases (Mn, Mg, Cu) its action was visible in both CV and GF animals. Steam-sterilized lactose (AuL) considerably reduced this effect and even reversed it. This change in lactose action under the effect of steam sterilization especially affected absorption, which declined for all the minerals, except Zn and Mn. It was accompanied by a drop in the digestive efficiency ratio which was particularly pronounced in GF rats. The destruction of 1/3 of dietary lactose by steam sterilization could not alone explain the differences between the effects of IL and AuL. Other factors, such as the products of the Maillard reaction formed by steam sterilization of the diet, might be implicated.

Animals↗
PubMed1977

Plasmids, loss of lactose metabolism, and appearance of partial and full lactose-fermenting revertants in Streptococcus cremoris B1.

The unstable ability to metabolize lactose (lac) via the phosphoenolpyruvate-phosphotransferase system (PTS) was examined in Streptococcus cremoris B1. The presence of functional lactose-specific PTS enzymes was correlated with the presence of a distinct plasmid species. Characterization of deoxyribonucleic acid extracted from lactose-positive (Lac+) S. cremoris B1 revealed two plasmids having molecular weights of 9 X 10(6) and 36 X 10(6). An acriflavine (BC1)-induced, lactose-negative (Lac-) mutant possessed no plasmids and was devoid of all three lac-specific PTS enzymes. A Lac- mutant (DA2) isolated by growing at elevated temperatures only possessed the 9 X 10(6)-dalton plasmid and also lacked the lac PTS enzymes. A spontaneous Lac- mutant possessed both the 9 X 10(6)-and 36 X 10(6)-dalton plasmids. This mutant displayed FIII-lac and phospho-beta-D-galactosidase (P-beta-gal) activity but was deficient in EII-lac activity. The spontaneous Lac- strain reverted to both full and partial lactose-fermenting phenotypes having FIII-lac, EII-lac, and P-beta-gal activities. BC1 and DA2 Lac- mutants reverted only to the partial lactose-fermenting phenotype having P-beta-gal activity; EII-lac and FIII-lac activities were absent. The results indicate that the genetic determinants for EII-lac, FIII-lac, and P-beta-gal are located on the 36 X 10(6)-dalton plasmid in S. cremoris B1. Evidence for a second chromosomally associated P-beta-gal gene operating in the partial lactose-fermenting revertants is also presented.

DNA, Bacterial↗
PubMed2006

Lactose-over-glucose preference in Bifidobacterium longum NCC2705: glcP, encoding a glucose transporter, is subject to lactose repression.

Analysis of culture supernatants obtained from Bifidobacterium longum NCC2705 grown on glucose and lactose revealed that glucose utilization is impaired until depletion of lactose. Thus, unlike many other bacteria, B. longum preferentially uses lactose rather than glucose as the primary carbon source. Glucose uptake experiments with B. longum cells showed that glucose transport was repressed in the presence of lactose. A comparative analysis of global gene expression profiling using DNA arrays led to the identification of only one gene repressed by lactose, the putative glucose transporter gene glcP. The functionality of GlcP as glucose transporter was demonstrated by heterologous complementation of a glucose transport-deficient Escherichia coli strain. Additionally, GlcP exhibited the highest substrate specificity for glucose. Primer extension and real-time PCR analyses confirmed that expression of glcP was mediated by lactose. Hence, our data demonstrate that the presence of lactose in culture medium leads to the repression of glucose transport and transcriptional down-regulation of the glucose transporter gene glcP. This may reflect the highly adapted life-style of B. longum in the gastrointestinal tract of mammals.

Bacterial Proteins↗
PubMed1980

Comparative tolerance of adolescents of differing ethic backgrounds to lactose-containing and lactose-free dairy drinks. I. Initial experience with a double-blind procedure.

A lactose-free (LF) chocolate dairy drink and one containing 4.5% lactose (LC) were administered randomly in 240- and 480-ml volumes on 4 consecutive mornings under double-blind conditions to 110 healthy teenagers (14 to 19 years old) of differing ethnic backgrounds. Capillary blood glucose analysis after 50 g of oral lactose identified 67 of them as lactose malabsorbers. Neither absorbers nor malabsorbers reported significantly different gastrointestinal symptoms after 240 ml of LC compared with the same amount of LF. However, 17 absorbers and 21 malabsorbers reported symptoms inconsistent with intolerance due to lactose. These subjects had symptoms after LF only, after both LF and LC, or after 240 ml but not 480 ml of LC. After 480 ml of LC, 26 malabsorbers had symptoms, compared to 15 after 480 ml of LF. The prevalence of symptoms after 480 ml of LC, but not after 480 ml of LF, was 7% for absorbers, and 24% for malabsorbers. The results indicate that most of the individuals who reported gastrointestinal symptoms after ingestion of the two beverages did so for reasons other than their lactose content.

Adolescent↗
PubMed1990

Simultaneous assessment of intestinal permeability and lactose tolerance with orally administered raffinose, lactose and L-arabinose.

1. In order to develop an improved differential sugar absorption test for simultaneously assessing intestinal permeability and lactose intolerance, methods were established for determining raffinose, lactose and L-arabinose in human urine. Using NAD(P)H-coupled enzymatic assays and fluorimetry, each sugar was measurable over a concentration range of approximately 3-300 mumol/l in diluted urine specimens. 2. After an overnight fast, 40 normal volunteers drank an iso-osmotic solution containing raffinose, lactose and L-arabinose. The median 5 h urinary sugar excretion was 0.26% of the ingested raffinose, 0.05% of lactose and 17.5% of L-arabinose. 3. In 143 patients with gastrointestinal disease, excretion of both ingested raffinose and lactose was significantly increased in coeliac disease in relapse or in partial remission and in Crohn's disease, but not in the irritable bowel syndrome, coeliac disease in remission or ulcerative colitis. Excretion of lactose, but not raffinose, was increased in patients with mucosal lactase deficiency, whereas excretion of L-arabinose was reduced in all disease groups except ulcerative colitis. 4. Discrimination between diseases was poor when based on individual sugar recoveries, but improved dramatically when excretion was expressed relative to that of L-arabinose. The raffinose/L-arabinose excretion ratio, an index of intestinal permeability, was greater than 0.08 in 15/15 untreated coeliac patients but less than 0.06 in all normal subjects and in 9/9 lactase-deficient patients, 15/16 recovered coeliac patients, 5/6 patients with ulcerative colitis, 13/16 patients with Crohn's disease and 61/62 patients with irritable bowel syndrome.

Adolescent↗
PubMed2005

Lactose intolerance: lactose tolerance test versus genotyping.

OBJECTIVE: Adult lactose intolerance, which affects the majority of the population in the world, has been associated with a single nucleotide polymorphism, C-13910T, located upstream of the lactase gene. MATERIAL AND METHODS: Adult patients undergoing lactose tolerance tests with lactose challenge and plasma glucose measurements were included in the study comprising 44 Swedes and 7 non-Swedish individuals. A real-time PCR method was established for the genotyping. RESULTS: Out of 51 patients 48 had concordant results on genotyping and lactose tolerance tests, e.g. -13910T/T and -13910C/T genotypes had high glucose elevations. All patients with the heterozygous genotype, -13910C/T, had high glucose elevations, and no gene-dose relationship was observed when comparing maximal glucose increases for cases with -13910C/T and -13910T/T genotypes. CONCLUSIONS: Genotyping could replace lactose challenge as a first-stage screening test in adults of European descent, but should be used together with tolerance tests in children and patients where secondary lactose intolerance is suspected.

Adult↗
PubMedDate not supplied

Developmental changes of lactose malabsorption in normal Chinese children: a study using breath hydrogen test with a physiological dose of lactose.

The malabsorption of a physiological dose of lactose (0.5 g/kg body weight) was studied in 726 healthy Chinese children, ranging in age from 3 to 18 years, using the breath hydrogen test. The prevalence of lactose malabsorption was found to increase with age; it occurred in less than 15% of preschool-age children and in approximately 45% of younger school-age and 60% of older school-age children. Approximately 70% of adolescents measured showed malabsorption. The critical period of change was from 6 to 7 years of age, with the lactose malabsorption rate rising abruptly from 12 to 43%. The incidence of lactose intolerance in teenagers and adolescents was 27 and 33%, respectively. The great majority of them had only dull abdominal pain. No case of lactose intolerance was seen in children less than 9 years of age. These results indicated that preschool Chinese children can absorb a physiological dose of lactose (equivalent to the average amount of milk consumed daily) without any adverse effects. In contrast, one half of school-age children and two thirds of adolescents were malabsorbers.

Administration, Oral↗
PubMed1982

Lactose malabsorption and tolerance of lactose-hydrolyzed milk. A double-blind controlled crossover study.

Eleven lactose-intolerant patients were investigated in a double-blind crossover controlled study. In random sequence they received 500 ml of either ordinary cow milk (lactose content, 25 g) or the same amount of low-lactose milk (85% of the lactose hydrolyzed), which had been processed by Lactozym 3000 L for 24 h at 4 degrees C. A significantly increased blood glucose rise from fasting levels was demonstrated in the low-lactose tests. Similarly, a significant reduction of liquid stool frequency, abdominal colics, distention, borborrhygmia, and flatulence was demonstrated. It was concluded that further studies, including long-term treatment of lactose-intolerant children, are indicated.

Adult↗
PubMed1982

Effect of fermentation on lactose, glucose, and galactose content in milk and suitability of fermented milk products for lactose intolerant individuals.

The lactose, glucose, and galactose content in various fermented milk products was studied by enzymatic methods. Lactose was decreased in all fermented products. After 11 days storage of yogurt the lactose content decreased to about 2.3 g/100 compared to 4.8 g/100 g in nonfermented milk. During the same period, galactose content increased from traces in milk to 1.3 g/100 g in yogurt. Results were similar with acidophilus and bifidus milk. Buttermilk, kefir, and ropy milk showed 26, 30, and 20% decreases in lactose content. Eight lactose intolerant individuals showed symptoms of abdominal distress and diarrhea following consumption of 500 ml of low fat milk whereas ingestion of the same quantity of yogurt or acidophilus milk did not result in any symptoms. Fermented milk products should be considered in formulating diets for lactose-intolerant subjects.

Adolescent↗
PubMed2004

[Lactose malabsorption in patients with inflammatory bowel disease without activity: would it be necessary to exclude lactose products in the diet of all patients?].

INTRODUCTION: There are inflammatory bowel disease (IBD) patients avoid lacteal products without evidence of lactose malabsorption, probably because of incorrect patient perceptions and arbitrary advice from physicians and diet books. AIM: To evaluate the prevalence of lactose malabsorption in patients with IBP. METHOD: In 18 patients with Crohńs disease and 24 with ulcerative colitis and 25 controls the prevalence of lactose intolerance, as measured by lactose breath hydrogen tests. RESULTS: Observed deficiencies of absorption of the lactose in 7 (16.6%) patients with IBP and 5 (20%) subjects control. CONCLUSIONS: Not all the patients with IBD are intolerant to the lactose by the suppression of the lacteal produts must not be generalized in the diet of these patients.

Adolescent↗
PubMed1991

Studies on the utilization of lactose by Corynebacterium glutamicum, bearing the lactose operon of Escherichia coli.

The entire Escherichia coli lactose operon was inserted into an E. coli/Corynebacterium glutamicum shuttle vector and introduced into the gram-positive host organism C. glutamicum R 163. Recombinant C. glutamicum strains carrying the lac genes downstream of an efficient promoter displayed rapid growth with lactose as the sole source of carbon. Two prerequisites were necessary to obtain good growth of C. glutamicum R 163 on lactose: presence of the lacY gene in addition to lacZ and an appropriate promoter for efficient transcription in C. glutamicum. The galactose moiety of lactose was not utilized but accumulated in the culture broth. C. glutamicum strains carrying only the lacZ (beta-galactosidase) gene but not lacY (lactose permease) were not able to grow in lactose minimal medium.

Base Sequence↗
PubMedDate not supplied

Normal plasma lactose concentrations and kinetics of intravenously infused lactose in cattle.

Plasma lactose concentration and its kinetics were determined in apparently normal cattle, as a prelude to investigating its chemotherapeutic significance in bovine trypanosomiasis. It is hoped that intravenously administered lactose may be able to reduce the rate of sequestration of desialylated erythrocytes during Trypanosoma vivax infection of cattle; thus decreasing the rate of development of trypanosomal anaemia in infected animals. A range of 0.061 to 0.55 mM with a mean of 0.208 +/- 0.128 mM standard deviation (SD), observed in adult cattle was significantly lower (P<0.001) than corresponding values in recently weaned calves; 0.429 to 1.496 mM (0.972 +/- 0.318 mM). Semi-logarithmic plots from calves given a single dose (0.5 g lactose per kg bodyweight as a solution in normal saline, infused at the rate of 18 ml min(-1)) showed a biexponential pattern of regression lines. Decrease in plasma concentrations was biphasic and lactose was rapidly distributed into the extravascular space after administration. The biological half-life (t1/2) of the infused lactose ranged from 4.10 to 6.00 hours (5.01 +/- 0.81 hours); its mean elimination rate constant was 0.14 +/- 0.02 hour(-1), mean apparent volume of distribution was 168.09 +/- 56.65 ml kg(-1) while its mean total clearance was 23.54 +/- 8.31 ml kg(-1) hour(-1). A single dose rapidly reached a peak and gradually fell below the pre-infusion level while repeated doses did not cause accumulation of the lactose in the plasma as each infusion fell back to normal relatively rapidly.

Animals↗
PubMed2001

The influence of excipients on the stability of the moisture sensitive drugs aspirin and niacinamide: comparison of tablets containing lactose monohydrate with tablets containing anhydrous lactose.

The purpose of this study is to test the hypothesis that in tablet formulations, moisture-sensitive drugs formulated with lactose monohydrate have the same stability as formulations containing anhydrous lactose, and to characterize the kinetics of niacinamide degradation in the solid state. Aspirin and niacinamide decomposition were used as indicators of stability. Aspirin and niacinamide tablets containing either lactose monohydrate or anhydrous lactose were separately investigated at different temperatures and relative humidities; the stability tests were done at 25 degrees C--60% RH, 40 degrees C--80% RH, 60 degrees C--60% RH, 60 degrees C--80% RH, and 80 degrees C--80% RH. Official U.S. Pharmacopeia methods were used for the aspirin and niacinamide assays. Statistical analysis showed that tablets containing lactose monohydrate have the same stability as tablets containing anhydrous lactose, which means that even though water is present in the crystal structure, the bound water does not influence the reaction rate. In addition, niacinamide degradation in the solid-state can be described by a third order rate equation.

Aspirin↗
PubMed1997

Lactose carrier mutants of Escherichia coli with changes in sugar recognition (lactose versus melibiose).

The purpose of this research was to identify amino acid residues that mediate substrate recognition in the lactose carrier of Escherichia coli. The lactose carrier transports the alpha-galactoside sugar melibiose as well as the beta-galactoside sugar lactose. Mutants from cells containing the lac genes on an F factor were selected by the ability to grow on succinate in the presence of the toxic galactoside beta-thio-o-nitrophenylgalactoside. Mutants that grew on melibiose minimal plates but failed to grow on lactose minimal plates were picked. In sugar transport assays, mutant cells showed the striking result of having low levels of lactose downhill transport but high levels of melibiose downhill transport. Accumulation (uphill) of melibiose was completely defective in all of the mutants. Kinetic analysis of melibiose transport in the mutants showed either no change or a greater than normal apparent affinity for melibiose. PCR was used to amplify the lacY DNA of each mutant, which was then sequenced by the Sanger method. The following six mutations were found in the lacY structural genes of individual mutants: Tyr-26-->Asp, Phe-27-->Tyr, Phe-29-->Leu, Asp-240-->Val, Leu-321-->Gln, and His-322-->Tyr. We conclude from these experiments that Tyr-26, Phe-27, Phe-29 (helix 1), Asp-240 (helix 7), Leu-321, and His-322 (helix 10) either directly or indirectly mediate sugar recognition in the lactose carrier of E. coli.

Amino Acids↗
PubMed1979

Breath hydrogen test for detecting lactose malabsorption in infants and children. Prevalence of lactose malabsorption in Japanese children and adults.

The breath hydrogen test (BHT) was adapted for use in young infants and children. The diagnostic criterion of sugar malabsorption in the BHT was determined by oral administration of 0.5 g/kg of unabsorbable sugar (lactulose) to 21 healthy infants and children. A maximum increase in breath hydrogen less than 0.05 ml/min per m2 was observed in all subjects. A good correlation between results by the BHT and by the ordinary lactose tolerance test was obtained after oral administration of 2 g/kg lactose to 21 healthy infants and children, 2 congenital lactase-deficient infants, and 7 adults. Using this test, 80 healthy Japanese infants and children (aged between one month and 15 years) and 18 adults were examined for lactose malabsorption after a dose of 1 g/kg lactose. All infants and children under 2-years old absorbed lactose completely. The incidence of lactose malabsorption was 30% in 3-year, 36% in 4-year, 58% in 5-year, and 86% in 6-year-old children, 85% in schoolchildren, and 89% in adults. Thus the incidence of lactase deficiency gradually increases with age from 3 years, and about 90% of all normal Japanese adults are lactase-deficient.

Adolescent↗