RESUMEN
The aims of this study were to measure the amount of starch from partially resistant starches (retrograded and complexed high-amylose cornstarches) escaping small-intestinal digestion in healthy humans by use of an intubation method and to compare these data with data obtained by indirect in vitro methods. Experiments were carried out in vivo in 6 healthy humans by using ileal intubation and stool analysis and in vitro by using 3 different methods for analyzing resistant starch. In intubated subjects, 51 +/- 2% of the retrograded and 21 +/- 2% of the complexed starch was delivered to the ileum and was fermented almost completely in the colon. In vitro estimates of the absorption of resistant starch were much lower. We conclude that technologically modified starches may substantially increase the amount of carbohydrate available for colonic fermentation in humans, but that in vitro measurements of resistant starch are inaccurate for predicting malabsorption in healthy humans.
Asunto(s)
Amilosa/metabolismo , Colon/metabolismo , Digestión/fisiología , Íleon/fisiología , Adulto , Amilosa/administración & dosificación , Amilosa/farmacología , Heces/química , Femenino , Fermentación , Humanos , Íleon/efectos de los fármacos , Intubación Gastrointestinal , MasculinoRESUMEN
This double-blind, double-dummy, randomized study compared the 24 h efficacy and safety of granisetron alone (3 mg i.v. over 30 s) or in combination with methylprednisolone (250 mg i.v. twice daily) in preventing nausea and vomiting in 308 patients (254 males) receiving high-dose cisplatin (100 mg/m2 or above) for mainly lung, and head and neck cancers. All patients received oral follow-on therapy comprising oral granisetron and methylprednisolone during the following 6 days. Primary efficacy variables were the proportions of complete responses (CR; no vomiting, no worse than mild nausea, no rescue and no withdrawal), no vomiting and no nausea over the first 24 h following initiation of the cisplatin infusion. The two treatment groups were well matched for demographics, cancer site, cisplatin dose and duration of infusion. Granisetron plus methylprednisolone was significantly more effective than granisetron alone for all primary efficacy variables: CR 78 versus 59% (p<0.001), no vomiting 80 versus 61% (p<0.001) and no nausea 74 versus 57% (p<0.002). Significantly more patients receiving the combination were free of any emetic symptoms (74 versus 54%, p<0.001). Significantly fewer patients receiving combination therapy also required rescue therapy with i.v. granisetron (12.2 versus 21.7%, p=0.026). During the follow-on period, complete response rates varied day by day from 50 to 71%. Both treatments were well tolerated, with constipation, abdominal pain and headache as the most frequent adverse events.
Asunto(s)
Antieméticos/uso terapéutico , Antineoplásicos/efectos adversos , Cisplatino/efectos adversos , Granisetrón/uso terapéutico , Metilprednisolona/uso terapéutico , Vómitos/prevención & control , Dolor Abdominal/inducido químicamente , Adolescente , Adulto , Anciano , Antieméticos/efectos adversos , Antineoplásicos/administración & dosificación , Antineoplásicos/uso terapéutico , Nitrógeno de la Urea Sanguínea , Cisplatino/administración & dosificación , Cisplatino/uso terapéutico , Estreñimiento/inducido químicamente , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Quimioterapia Combinada , Femenino , Estudios de Seguimiento , Granisetrón/efectos adversos , Cefalea/inducido químicamente , Humanos , Leucopenia/inducido químicamente , Masculino , Metilprednisolona/efectos adversos , Persona de Mediana Edad , Nitrógeno/sangre , Resultado del Tratamiento , Vómitos/inducido químicamente , Vómitos/tratamiento farmacológicoRESUMEN
OBJECTIVE: To evaluate in 14 healthy volunteers the gastrointestinal tolerance to an indigestible bulking sweetener containing fructo-oligosaccharides (FOS). DESIGN: In order to mimic their usual pattern of consumption, FOS were ingested throughout the day either occasionally (once a week, first period) or regularly (every day, second period). In the two patterns of consumption, daily sugar doses were increased until diarrhoea and/or a symptom graded 3 (i.e. severe) occurred, or when subjects did not want to ingest more candies. SETTING: Clinical Nutrition Unit, Hôpital Saint-Lazare, Paris. RESULTS: In both periods, the first symptom which occurred was excessive flatus (> 30 g FOS/day): borborygmi and bloating appeared at a higher level (> 40 g/day); lastly, abdominal cramps and diarrhoea occurred at a very much higher level (50 g/day). The volumes of hydrogen excreted in breath in response to the same load of FOS were not different between the two periods. CONCLUSIONS: Chronic consumption of FOS initiated cautiously with subsequent gradual increase did not improve tolerance, nor reduce breath excretion of hydrogen.
Asunto(s)
Carbohidratos de la Dieta/efectos adversos , Oligosacáridos/efectos adversos , Adulto , Pruebas Respiratorias , Estudios Cruzados , Diarrea/inducido químicamente , Carbohidratos de la Dieta/administración & dosificación , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Femenino , Intolerancia a la Fructosa/inducido químicamente , Humanos , Hidrógeno/análisis , Masculino , Oligosacáridos/administración & dosificaciónRESUMEN
The digestibility of ispaghula, a mucilage from Plantago ovata composed mainly of arabinoxylans, and its faecal bulking effect were studied in seven healthy volunteers who ingested a low fibre controlled diet plus either placebo or 18 g/day of ispaghula for two 15 day periods. Whole gut transit time and gas excretion in breath and flatus were not different during the periods of ispaghula and placebo ingestion. Faecal wet and dry weights rose significantly, however, during ispaghula ingestion. Faecal short chain fatty acid concentrations and the molar proportions of propionic and acetic acids also increased. Most of the ispaghula had reached the caecum four hours after ingestion in an intact highly polymerised form. During ispaghula ingestion, the increase in the faecal output of neutral sugars was accounted for by the faecal excretion of arabinose and xylose in an intact highly polymerised form; the apparent digestibilities of these sugars were 24 (11) and 53% (6) respectively (mean (SEM)). In conclusion, ispaghula is more resistant to fermentation than previously reported in humans, and its bulking effect largely results from intact material.
Asunto(s)
Fibras de la Dieta , Tránsito Gastrointestinal , Psyllium , Acetatos/análisis , Adulto , Arabinosa/análisis , Pruebas Respiratorias , Estudios Cruzados , Digestión , Ácidos Grasos Volátiles/análisis , Heces/química , Femenino , Gases/análisis , Humanos , Masculino , Propionatos/análisis , Xilosa/análisisRESUMEN
We studied seven healthy volunteers before and during acute (PD1) and chronic (PD2) ingestion of 30 g polydextrose (PD)/d. The energy value of PD was assessed after [U-14C]PD was added to the 10-g morning dose of PD during PD1 and at the end of PD2. Thirty-one +/- five percent (mean +/- SD) (PD1) and 29 +/- 4% (PD2) of the dose appeared in breath within 48 h. A small fraction of the ingested radioactivity was recovered in urine (4 +/- 1%) and excreted in flatus (< or = 1%) and in feces as volatile fatty acids (VFAs) (< 1%) and bacteria (3-4%); the remaining radioactivity in stools, 33 +/- 3% (PD1) and 32 +/- 4% (PD2), was assumed to be intact PD. Breath excretion of the label was 49 +/- 5% after intracolonic infusion of [U-14C] acetate. The energy value of PD, calculated by means of Miller and Wolin's stoichiometric equation of colonic fermentation, was similar during PD1 and PD2: 4.0 and 6.1 kJ/g, respectively, when breath 14CO2 and VFA production from PD were used for calculation.
Asunto(s)
Sistema Digestivo/efectos de los fármacos , Metabolismo Energético/fisiología , Aditivos Alimentarios/metabolismo , Glucanos/metabolismo , Adulto , Pruebas Respiratorias , Dióxido de Carbono/análisis , Sistema Digestivo/microbiología , Heces/química , Fermentación , Aditivos Alimentarios/farmacología , Glucanos/farmacología , Humanos , Masculino , Modelos Teóricos , Obesidad/metabolismo , Valores de ReferenciaRESUMEN
BACKGROUND: A major limitation in studying the proximal human colonic flora is the lack of suitable sampling methods. The aim of this study was (1) to describe a prototype technique, pyxigraphy, which uses swallowed capsules containing a mechanism allowing the remote control of sampling the gastrointestinal tract contents, and (2) to use this sampling method to examine the distribution of methanogens in the colon of methane (CH4) excretors and non-CH4 excretors. METHODS: In six CH4 excretors and four non-CH4 excretors, samples of the right colonic contents were obtained by means of the pyxigraphic sampling method. Methanogens and total anaerobes were enumerated in both the right colonic and fecal contents. RESULTS: In CH4 excretors, the concentration of methanogens was higher in the feces than in the right colonic contents, representing 12% and 0.003%, respectively, of the total anacrobes (P < 0.02). In non-CH4 excretors, no difference was observed, methanogens representing < 0.003% of the total anaerobes in both the right colonic and fecal contents. CONCLUSIONS: Pyxigraphy is a noninvasive, simple, and safe sampling method that allows to study the microbial populations of the proximal colon. The results obtained showed that methanogens preferentially colonize the distal part of the colon in CH4 excretors.
Asunto(s)
Bacterias Anaerobias/aislamiento & purificación , Colon/microbiología , Euryarchaeota/aislamiento & purificación , Adulto , Técnicas Bacteriológicas , Heces/microbiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Manejo de EspecímenesRESUMEN
Twelve healthy volunteers were studied for two test periods, at the beginning of which they ingested a diarrheogenic load (60 g) of lactulose in 350 mL water with 10 g polyethylene glycol 4000 (PEG); the two periods were separated by a lactulose feeding period of 8 d, during which a nondiarrheogenic load (20 g) of lactulose was taken twice daily. The transit time and flow rates of water and lactulose in the distal ileum of four subjects were not different before and after the lactulose feeding period. In the other eight subjects, stool weight and frequency, fecal pH, and fecal outputs of carbohydrates and osmotic moieties after the ingestion of 60 g lactulose dropped significantly (P < 0.05) after the lactulose feeding period, whereas the orofecal transit time and fecal concentrations of beta-galactosidase and lactic acid increased (P < 0.05). We conclude that changes in colonic function induced by prolonged exposure to a nondiarrheogenic amount of lactulose mitigate the severity of the diarrhea because of the larger dose of lactulose.
Asunto(s)
Diarrea/inducido químicamente , Diarrea/tratamiento farmacológico , Lactulosa/uso terapéutico , Adulto , Defecación , Heces/química , Femenino , Tránsito Gastrointestinal , Humanos , Íleon/metabolismo , Lactatos/análisis , Ácido Láctico , Masculino , Factores de Tiempo , Agua/metabolismo , beta-Galactosidasa/análisisRESUMEN
On two occasions separated by seven days, 22 g mucin (hog gastric mucin) was infused into right and left colon of 12 healthy volunteers (6 CH4 producers and 6 non-producers) maintained on a controlled diet. In the six CH4 producers, excess volumes of H2 excreted in breath were 73.4 +/- 11.9 and 35.1 +/- 14.1 (SE) ml/8 h (P less than 0.05) in response to right and left colonic infusion of mucin, respectively; excess volumes of CH4 were, respectively, 6.7 +/- 1.7 and 38.9 +/- 11.1 ml/8 h (P less than 0.05). In the six CH4 nonproducers, excess volumes of H2 excreted in breath were 76.6 +/- 17.6 and 30.8 +/- 6.3 ml/8 h (P less than 0.02) in response to right and left colonic infusion of mucin, respectively; excess volumes of CH4 were, respectively, 0.0 +/- 0.0 and 0.1 +/- 0.1 ml/8 h (not significant). In a further experiment, 17 healthy volunteers (10 CH4 producers and 7 nonproducers) were given on 2 consecutive days an oral load and an enema of 10 g lactulose. In the 10 CH4 producers, excess volumes of H2 excreted in breath were 74.6 +/- 15.1 and 32.3 +/- 11.5 ml/6 h (P less than 0.001) in response to oral ingestion and lactulose enema, respectively; excess volumes of CH4 were, respectively, 7.7 +/- 3.0 and 38.2 +/- 7.2 ml/6 h (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Colon/fisiología , Metano/metabolismo , Mucinas/metabolismo , Adulto , Animales , Femenino , Humanos , Hidrógeno/metabolismo , Cinética , Lactulosa/metabolismo , Masculino , Valores de Referencia , Respiración , Porcinos , Factores de TiempoRESUMEN
Sugar alcohols are incompletely digested in the human small intestine. The residual amounts reaching the colon are digested by colonic bacteria or excreted in stools. Clinical tolerance and energy value of sugar alcohols are related to their respective rates of digestion in the small intestine and the colon. Six healthy volunteers were tested in 5 periods during which they ingested 10 g lactulose, and then, in a random order, an iso-osmotic solution of 20 g isomalt, sorbitol, maltitol, and lactitol. The fraction of sugar alcohols absorbed in the small intestine was evaluated by comparing the amounts of hydrogen excreted in breath for 8 h after the ingestion of lactulose and of sugar alcohols. Energy value of sugar alcohols was determined knowing the amounts absorbed in the small intestine and digested in the colon. Tolerance to the sugar alcohols was good in all volunteers, and not different between sugar alcohols. The mean percentage of malabsorption in the small intestine was significantly higher for lactitol (84 +/- 14 percent, m +/- SEM) than for maltitol and isomalt (44 +/- 7 and 40 +/- 7 percent), its energy value (2.3 +/- 0.3 kcal/g) was significantly lower than the energy value of maltitol (3.1 +/- 0.1 kcal/g, P less than 0.05); whereas those of sorbitol and isomalt were close (2.7 +/- 0.2 and 2.8 +/- 0.1 kcal/g, respectively). In spite of these differences, our results suggest that in our experimental conditions, bacterial digestion of the sugar alcohols reaching the colon was complete, and did not affect their clinical tolerance.
Asunto(s)
Absorción Intestinal/efectos de los fármacos , Isomaltosa/farmacología , Maltosa/análogos & derivados , Sorbitol/farmacología , Alcoholes del Azúcar/farmacología , Adulto , Femenino , Humanos , Isomaltosa/efectos adversos , Isomaltosa/metabolismo , Lactulosa/efectos adversos , Lactulosa/metabolismo , Lactulosa/farmacología , Masculino , Maltosa/efectos adversos , Maltosa/metabolismo , Maltosa/farmacología , Valores de Referencia , Sorbitol/efectos adversos , Sorbitol/metabolismo , Alcoholes del Azúcar/efectos adversos , Alcoholes del Azúcar/metabolismoRESUMEN
Nine healthy volunteers were studied before, during, and after ingesting a fermented dairy product containing Lactobacillus acidophilus, Bifidobacterium bifidum, and mesophilic cultures (Streptococcus lactis and S cremoris) for 3 wk. Hydrogen and methane productions and fecal beta-galactosidase and beta-glucosidase activities were measured as indicators of fermentation capacity of the colonic flora. Fecal concentrations of nitroreductase, azoreductase, and beta-glucuronidase, which may be implicated in colonic carcinogenesis, were also assessed. Hydrogen and methane productions, fecal beta-galactosidase, beta-glucuronidase, and azoreductase activities did not change over three 3-wk periods whereas fecal beta-glucosidase activity increased (42 +/- 6, 91 +/- 12, and 40 +/- 6 IU/g N, P less than 0.01) and nitroreductase decreased (0.87 +/- 0.13, 0.54 +/- 0.11, and 0.57 +/- 0.08 IU/g N, P less than 0.05).
Asunto(s)
Bifidobacterium/fisiología , Colon/microbiología , Productos Lácteos , Fermentación , Lactobacillus acidophilus/fisiología , Adulto , Bifidobacterium/enzimología , Heces/enzimología , Femenino , Glucuronidasa/metabolismo , Humanos , Hidrógeno , Masculino , Metano , NADH NADPH Oxidorreductasas/metabolismo , Nitrorreductasas , Respiración , Factores de Tiempo , beta-Glucosidasa/metabolismoRESUMEN
The digestion and absorption of three sugar alcohols, consumed chronically in three identical daily postprandial doses, were evaluated in six volunteers during three 11-day periods. Each period included a 3-day adaptation period during which sugar alcohol doses were increased, a 4-day equilibration period, a 2-day stool collection period, and a 2-day intubation period. From day 4, the daily administered amounts were either 30 g pure sorbitol, 57 g maltitol containing 30 g sorbitol, or 69 g Lycasin 80/55 (Roquette, Lestrem, France), which is a hydrogenated glucose syrup also containing 30 g sorbitol. The distal ileal output of sugar alcohols and their components was determined by aspiration after a single meal. The mean percentage of sorbitol absorbed in the small intestine was significantly higher in pure sorbitol doses than in those containing maltitol and Lycasin 80/55 (79% +/- 4% vs. 64% +/- 4% and 64% +/- 5%, mean +/- SEM). The mean percentage of total maltitol digested was not different for pure maltitol and maltitol contained in Lycasin 80/55 (90% +/- 2% vs. 86% +/- 2%). Stool excretion of sugar alcohols was negligible, indicating that the sugar alcohols reaching the colon were almost completely digested by the colonic flora. The mean estimated energy values of the sugar alcohols ingested in kcal/g were 3.58 +/- 0.08 for sorbitol, about 3.50 +/- 0.07 for maltitol, and between 3.11 +/- 0.08 and 3.54 +/- 0.08 for Lycasin 80/55. Because the experimental conditions of this study mimicked the usual way of consumption of the three sugar alcohols, little calorie saving can be expected from the chronic consumption of these sugar alcohols in so-called sugar-free products.
Asunto(s)
Digestión/fisiología , Absorción Intestinal/fisiología , Alcoholes del Azúcar/farmacocinética , Edulcorantes/farmacocinética , Adulto , Metabolismo Energético/fisiología , Heces/análisis , Humanos , Íleon/metabolismo , Masculino , Maltosa/análogos & derivados , Maltosa/farmacocinética , Valores de Referencia , Sorbitol/farmacocinéticaRESUMEN
Rates of hydrogen and methane production were compared in caecal and faecal homogenates in six methane producers. Faecal homogenates produced hydrogen and methane in the absence of and after the addition of lactulose, whereas caecal homogenates produced hydrogen but little methane.