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At least 649 records · Page 36Linked to original sources
PubMed1974

Electron microscopic study on the jejunal mucosa in human cholera.

Small intestinal mucosa obtained from six fasting patients with cholera by a peroral biopsy technique was studied with the electron microscope. The cultures of their rectal swabs were all positive for Vibrio cholerae. In the absorptive cells, large pseudopod-like cytoplasmic processes with deformed microvilli or without microvilli (blebs) projected into the intestinal lumen from the apical cell surface, interrupting the microvillous border. In the crypts some of the undifferentiated crypt cells possessed pseudopod-like cytoplasmic projections which extended into the crypt lumen. The swelling of mitochondria, the disappearance of their cristae, an increase in the number of vesicles of the Golgi apparatus, and the dilatation and vesiculation of endoplasmic reticulum were observed in the epithelial cells. The apical portion of the cells became oedematous in some of the epithelial cells. Cytoplasmic fragments enclosed by a plasma membrane, desquamated epithelial cells, cytoplasmic organelles, and secretory granules were lying free in the intestinal lumen.Marked irregular widening of the interepithelial spaces in the jejunal mucoa was observed at the midvillous area. Many cystic vacuoles were present in the cytoplasm of epithelial cells. The possibility of fluids being transported from blood vessels to intestinal lumina through the interepithelial spaces, and the significance of these pathological findings in human cholera are discussed in this study.

Adult↗
PubMed1990

Indomethacin sustained-release suppositories containing sugar ester in polyethylene glycol base.

Indomethacin (IM) sustained-release suppositories were prepared by the fusion method using sugar ester and polyethylene glycol 4000 (PEG). The suppositories were evaluated by in vitro release testing, X-ray analysis and in vivo absorption testing in rabbits. X-ray analysis showed that IM was amorphous in PEG-base suppositories. In a release test, slow-release was obtained when the sugar ester content of a suppository was 60%. The IM plasma level following the administration of the suppository was well sustained in the absorption test. The main slow-release mechanism is considered to be the release of IM from the matrix composed of sugar ester and PEG, which is represented by the Higuchi equation. A good correlation between the release test and the absorption test was obtained. It is considered that the amorphous state of IM in this type of sustained-release suppository would enhance the release and absorption of IM in the rectum of the rabbit, whose rectal fluid volume is small.

Animals↗
PubMed1985

Whole bowel irrigation for toxic ingestions.

Eight children aged eleven months to sixteen years who ingested toxic substances were treated with whole bowel irrigation. This procedure involves the rapid infusion of fluids per nasogastric tube in order to flush the toxic substance out from the gastrointestinal tract thereby preventing its absorption into the bloodstream. The infusion is terminated when the rectal effluent takes on the characteristics of the infusate. The toxic substances included miniature disc batteries, iron, tricyclic antidepressant and paraquat. No significant changes in serum sodium, serum potassium or hematocrit were observed. Whole bowel irrigation was felt to be efficacious in this series. It requires additional study as a therapeutic approach to the patient who has ingested a toxic substance.

Adolescent↗
PubMed1991

Pharmacokinetic evaluation of ethionamide suppositories.

The absorption and elimination of ethionamide (ETA) after oral tablets and rectal suppositories were determined in 12 healthy, adult male volunteers. A randomized, double-blind, double-dummy, crossover design was used. Treatments compared 250-mg ETA tablets and a placebo suppository to a 500-mg ETA suppository and two placebo tablets, given 7 days apart. Blood samples were collected at predetermined intervals for 12 hours after the dose. Serum concentrations of ETA were determined using high-performance liquid chromatography. The area under the serum concentration-time curve was used to compare the relative bioavailability of ETA from the two preparations. Relative bioavailability after rectal administration was 57.3% of that after oral administration. The maximum serum concentration after rectal administration was 33% of that after oral administration. Higher doses of ETA and serum concentration monitoring are recommended whenever the suppositories are used.

Administration, Oral↗
PubMed1988

[Oxygen partial pressure after rectal oxygen insufflation-- experimental animal studies].

An oxygen diffusion through the mucosa of the colon into the vessels of the submucous coat was provable after rectal insufflation of an oxygen-gas mixture by animal experimental investigations in rabbits. Significantly higher pO2 values in the blood of the mesocolon veins, the portal vein, in the arterial and venous mixed blood of the liver parenchyma, and in the arterial vessels of the mesocolon are measurable after rectal application of oxygen during a time of 40 minutes. The oxygen therapy after rectal oxygen insufflation is established by animal experiments.

Administration, Rectal↗
PubMed1985

The permeability of normal, adenomatous, ulcerative colitic and malignant large bowel epithelial cell membranes to inulin.

We measured the permeability of normal, adenomatous, colitic and malignant large bowel epithelial cells by immersing fragments of large bowel mucosa in radiolabelled inulin and comparing autoradiograph grain density inside and outside cells after incubation. All the carcinomas studied showed extensive uptake of inulin within 5 min, while normal, adenomatous and colitic epithelial cells completely excluded inulin for 30 min. We found no difference in the proportion of epithelial cells incorporating uridine into RNA in carcinomatous and normal mucosa, and this suggests that the increased inulin permeability of carcinoma cell membranes was not due to leakage into non-viable cells. Experiments with cytochalasin B also showed that increased pinocytosis by carcinoma cells could not account for the difference. The relative impermeability of adenomatous and colitic cells suggests that increased permeability is not caused by increased proliferation. The consistent finding of increased permeability in the plasma membranes of carcinoma cells suggests that this may be more than an epiphenomenon of malignancy. It also suggests that measurement of cell permeability may have a role in distinguishing malignant from benign epithelial neoplasms.

Adenoma↗
PubMed1982

[The measurement of DNA in material obtained by cyto-puncture of the prostate. Diagnostic, prognostic and therapeutic value (author's transl)].

The results of the measurement of deoxyribonucleic acid (DNA) by absorption cytophotometry after Feulgen reaction, in smears of trans-rectal fine needle aspiration of prostate cancers are exposed. The histograms may be distributed in 3 categories: poorly, moderately and highly aneuploïds and heteroplöids. The correlation between the category of ploïdy and the cytological grade is fair but the measurement of DNA offers a diagnostic and prognostic refinement: it distinguishes, among the grade 2 cancers (moderately differenciated) tumours with different potential evolutivity. Repeated measurements in treated patients (with orchiectomy or estrogens) give objective criterias of therapeutical response. Following our experience, the persistence or the reappearance of important abnormalities in the histogram in a treated patient are objective and often premonitory signs of therapeutical escape which invite, even in the absence of clinical evidence of progression, to change the treatment.

DNA, Neoplasm↗
PubMed1984

Rectal, oral and I.A. administration of etomidate to rats: significant avoidance of hepatic first-pass elimination following rectal administration.

The systemic availabilities of the hepatic high-clearance drug etomidate following oral and rectal administration to rats were determined. The mean curve following intra-arterial administration to another group of rats was taken as a reference. The results showed that the mean rectal systemic availabilities calculated according to the AUC method and the deconvolution method were considerably higher (70.1% and 67.6% respectively) as compared to the mean values following oral administration (4.5% and 9.2% respectively). The deconvolution method gave detailed information about the profiles of the rate and cumulative amount of drug absorbed versus time. It showed that the mean maximal rate of absorption was higher and the time at which this occurred was shorter after rectal (5343 micrograms/hr and 0.13 hr) than after oral (600 micrograms/hr and 0.23 hr) administration. Mean blood elimination half-lives following rectal administration (112.6 min) were longer than that after i.a. administration (61.7 min). The mean half-life of 22.8 min after oral administration should be considered as a distribution half-life. The mean clearance following i.a. administration was 35.2 ml/min (142.7 ml/min/kg), which is higher than hepatic bloodflow and indicates extra-hepatic metabolism. It is concluded that there is a substantial avoidance of hepatic first-pass elimination of etomidate following rectal administration to rats.

Administration, Oral↗
PubMed1992

Comparative oxycodone pharmacokinetics in humans after intravenous, oral, and rectal administration.

The pharmacokinetics of oxycodone have been determined after single-dose administration by the intravenous (4.6-7.3 mg), oral (tablets, 9.1 mg and syrup, 9.1 mg), and rectal (30 mg) routes, in 48 patients undergoing minor surgery. There were no significant differences in the mean elimination half-lives between the intravenous (5.45 +/- 1.43 h), oral tablets (5.65 +/- 1.13 h), oral syrup (4.80 +/- 1.13 h), and rectal suppository (5.40 +/- 1.19 h) formulations of oxycodone. After intravenous administration, the mean plasma clearance of oxycodone was 25.5 +/- 10.1 L/h and the mean volume of distribution at steady state was 2.5 +/- 0.8 L/kg. The mean normalized area under the curve (AUC/D) obtained after intravenous dosing (48.2 +/- 30.2 micrograms.h/L/mg) was more than twice the AUC/D values obtained after the administration of oxycodone tablets (19.8 +/- 3.5 micrograms.h/L/mg), oxycodone syrup (17.5 +/- 5.3 micrograms.h/L/mg), and rectal suppository (20.3 +/- 5.1 micrograms.h/L/mg), indicating that the amount of oxycodone reaching the systemic circulation after the extravascular routes of administration was < 50% of that obtained after intravenous dosing. The mean absorption lag times after oxycodone tablets (0.52 +/- 0.33 h), oxycodone syrup (0.48 +/- 0.40 h), and rectal suppository (0.76 +/- 0.47 h) were consistent with the onset of pharmacological effects reported by the patients.

Administration, Oral↗
PubMed1993

[Absorption and first-pass-effect of salbutamol after intraduodenal and intrarectal administration in rabbits].

To understand the previous result of higher bioavailability of rectal salbutamol (SB) compared with oral SB, in situ experiments using rabbit duodenal and rectal loop were carried out. After the intravenous (i.v.) and intraportal (i.p.) dosing of SB, fraction of dose which avoids the hepatic first-pass-effect (Fh) was calculated from the areas under the blood concentration-time curve (AUC). The Fh was about 10% and unchanged significantly with increasing i.p. dose (5-20 mg). Intraduodenal (i.d.) or intrarectal (i.r.) dosing of SB was made after the i.v. and i.p. dosing, and the AUC's and the residual amount in the loop were obtained to estimate the parameters. The results of the i.d. and i.r. dosing were as follows; for the extent of bioavailability (EBA), 7.7 +/- 1.5% and 14.5 +/- 2.3%, for the fraction of dose absorbed (fa), 93.9 +/- 3.7% and 33.8 +/- 3.3%, and for the fraction of absorbed SB which avoids first-pass-effects (F), 8.4 +/- 1.9% and 43.0 +/- 6.0% (mean +/- S. E., n = 4). Consequently, SB dosed i.d. was absorbed completely, and received first-pass-metabolism in the mucosa (about 20%) and then in the liver (about 90%), which caused the low bioavailability. While, in i.r. dosing, SB absorption was poor. However, higher bioavailability was obtained owing to about 40% of rectal venous blood flow which bypasses the liver and negligible first-pass-metabolism in the mucosa (about 4%).

Administration, Rectal↗
PubMed1996

Fluorine-18 fluoro-2-deoxyglucose positron emission tomography in recurrent rectal cancer: relation to tumour size and cellularity.

The aim of this study was to assess the value of fluorine-18 fluoro-2-deoxyglucose (FDG) positron emission tomography in patients with recurrent rectal cancer, in relation to tumour size and cellularity. Thirty-seven patients (21 mean and 16 women; mean age, 55.4+/-9.58 years) with suspected recurrence of rectal cancer were studied. FDG uptake was quantified by the differential absorption ratio (DAR). In 29 patients magnetic resonance imaging was also performed. To evaluate the signal intensity of the lesion, the lesion to muscle signal intensity ratios (SIR) were calculated on T2-weighted images. In seven patients who received surgical treatment the DAR and SIR were compared with the tumour cellularity. All 32 patients with confirmed recurrence showed increased FDG accumulation in the mass (DAR=4.57+/-1.89) in comparison with low FDG accumulation in five patients with scar (DAR=1.17+/-0.43). There was a significant correlation (r=0.661, P<0.001) between the DAR and the tumour diameter. There was no correlation between the DAR and SIR, whereas there was a significant correlation (r=0.565, P<0.01) between the DAR corrected using count recovery coefficient (DAR*) and SIR. In the histopathological findings there was a tendency for the DAR* and SIR to correlate with tumour cellularity. It is concluded that the DAR of recurrent rectal cancer should be evaluated taking into consideration the tumour size and cellularity.

Deoxyglucose↗
PubMedDate not supplied

Plasma concentrations and bioavailability of propranolol by oral, rectal, and intravenous administration in man.

Eight normal male volunteers received 80 mg doses of propranolol by the oral and rectal routes and 2.2 mg by intravenous administration in a crossover fashion. Plasma concentrations of propranolol were measured by a gas chromatographic method using an electron capture detector. Individual subject concentration-time data were analysed and results indicated that the data fit a two compartment model with first order absorption. An approximately two-fold higher plasma propranolol concentration was observed after rectal administration as compared with oral dosing. Statistical analysis of the difference in the total AUCs indicates a significantly higher bioavailability of propranolol administered by the rectal route. The reduced bioavailability after oral administration indicates a substantial first pass effect but that it is possible to bypass the liver, at least partially, by giving the drug rectally to man.

Administration, Oral↗
PubMed2001

Poloxamer 407 as a thermogelling and adhesive polymer for rectal administration of short-chain fatty acids.

OBJECTIVES: The purpose of the study was to gel a rectal solution of short-chain fatty acids to decrease the loss of active materials in the colonic lumen and thereby optimize their absorption. METHODS: Five thermogels were prepared with poloxamer 407 at concentrations ranging from 17% to 20%. Their viscosities were measured at room temperature and 37 degrees C, and their gelling temperatures were determined. The adhesive properties of each gel were assessed in vitro at 37 degrees C. Short-chain fatty acid release was studied using Guyot cells. RESULTS: From the threshold concentration of 17.5%, the solutions, Newtonian at room temperature (50-80 mPa x s), gelled at 37 degrees C. The higher the concentration, the higher the viscosity (1750 to 49,000 mPa x s), the lower the gelling temperature (27.6 degrees C to 23.4 degrees C), and the stronger the work of adhesion (2.2 to 4.5 mJ). Short-chain fatty acid release from the 18% polymer gel was decreased by 60% compared to the rectal solution. CONCLUSION: The 18% poloxamer 407 concentration provided a solution that was liquid at room temperature, that gelled at 37 degrees C, possessed adhesive properties, and controlled short-chain fatty acid release.

Absorption↗
PubMed1978

[Enteric hyperoxaluria. I. Intestinal oxalate absorption in gastrointestinal diseases (author's transl)].

Oxalate-urolithiasis and hyperoxalaria have been reported to be a frequent complication in patients with small bowel disease, especially in patients with ileal resection due to Crohn's disease. Hyperabsorption of oxalate seems to be the main patholgenetic factor for "enteric" hyperoxalaria. Intestinal absorption and urinary excretion of oxalate was measured in patients with various gastrointestinal diseases after oral or rectal administration of 14C-oxalate. Kinetic data suggest that 14C-oxalate is absorbed in the small, the large bowel and the rectum as well. Oxalate absorption was decreased in patients with a colectomy and in active ulcerative colitis, but increased in patients with ileal resection, chronic liver disease, and steatorrhea due to chronic pancratitis or sprue. There existed a positive correlation between 14C-oxalate absorption and the amount of fecal fat excretion. The data suggest that hyperoxaluria and hyperabsorption of oxalate are not a specific finding in patients with bile acid malabsorption, but may occur too, in steatorrhea without alteration of bile acid metabolism.

Celiac Disease↗
PubMed2001

Preparation and characterization of insulin-loaded acrylic hydrogels containing absorption enhancers.

The objectives of this study were to prepare insulin-loaded acrylic hydrogel formulations containing various absorption enhancers, to perform in vitro and in vivo characterization of these formulations, and to evaluate the factors which affecting insulin availability on rectal delivery of insulin using this hydrogel system. The acrylic block copolymer of methacrylic acid and methacrylate, Eudispert, was used to make the hydrogel formulations. As absorption enhancers, 2,6-di-O-methyl-beta-cyclodextrin (DM-beta-CyD), lauric acid (C12), or the sodium salt of C12 (C12Na), were incorporated into the hydrogels. In an in vitro release test, the release rate of insulin from the hydrogels decreased as the polymer concentration of the hydrogel increased. The addition of C12Na to the hydrogel further increased the insulin release rate, which was greater at higher concentrations of the enhancer. A portion of the C12Na was found to remain bound to the acrylic polymer in dissolution medium. Serum insulin levels were determined at various time points after the administration of insulin solution or insulin-loaded (50 units/kg body weight) Eudispert hydrogels containing 5% (w/w) of C12, C12Na, or DM-beta-CyD to in situ loops in various regions of the rat intestine. The most effective enhancement of insulin release was observed with formulations containing C12Na. The bioavailability of insulin from the hydrogels was lower than that from the insulin solutions. Hydrogel formulations containing 7% or 10% Eudispert remained in the rectum for 5 h after rectal administration. However, the 5% (w/w) C12Na solution stained with Evan's-blue had diffused out and the dye had reached the upper intestinal tract within 2 h. Finally, the rectal administration of insulin-loaded hydrogels, containing 4%, 7%, or 10% (w/w) Eudispert and 5% (w/w) of enhancer (C12, C12Na, or DM-beta-CyD) to normal rats was shown to decrease serum glucose concentrations. The greatest effect was found with insulin-loaded 7% (Eudispert) hydrogel containing C12Na which having cosiderable large insulin release rate and bioadhesive characteristics.

Acrylates↗
PubMed1989

Study on absorption of indomethacin from sustained-release suppositories containing hydrogenated soybean lecithin in rabbits.

The absorption of indomethacin (IM) from suppositories containing hydrogenated soybean lecithin (HL) after rectal administration in rabbits was investigated with the aim of producing sustained-release suppositories. The suppositories were prepared by the fusion method with IM, HL and Witepsol H-15 (H-15). The IM release rate from the suppositories (IM 10 mg, HL 200 mg, total weight 1 g) was faster than that of the control suppositories without HL. The release of IM from the suppositories (IM 10 mg, HL 300 mg or 350 mg) showed slow-release profiles. In absorption studies in rabbits, sustained-plasma levels of IM were obtained when suppositories having an HL content of more than 300 mg were administered. The suppositories composed of Witepsol E-85 (melting point approximately 43 degrees C), 10 mg of IM, and 200 mg of HL, showed slow-release profiles in the release test, but did not show sustained plasma levels of IM in the absorption test. These results indicate that sustained-release suppositories able to release IM gradually from the surface of the suppositories can be obtained when HL, IM and H-15, whose melting point is lower than body temperature, are used in the preparation of the suppositories, provided that the HL content is high enough in relation to IM.

Animals↗
PubMedDate not supplied

[Transdermal therapeutic methods].

Percutaneous absorption has now been largely demonstrated and is defined as the passage of a molecule applied to the skin from the external environment to the blood. This phenomenon takes place in two main steps: penetration and actual absorption. Percutaneous absorption avoids the first-pass effect to which orally and rectally administered molecules are submitted, although these molecules can be metabolized in the skin, but to a much lesser degree that by hepatic metabolism. Transdermal devices present many advantage compared to forms administered by other routes: improved patient compliance, easy self-administration, prolonged plasma plateau levels. However, it depends on the skin type and, in the case of allergic reactions, other classical forms designed for the cutaneous route, such as ointments or gels. There are two types of transdermal device: so-called matricial forms, which are semi-solid or solid preparations in which the active ingredient(s) can be dispersed or dissolved; reservoir systems, in which one of the walls is a membrane, placed directly on the skin. In the case of the nitroglycerin, plasma curves are essentially identical regardless of the type of device used. The active ingredients currently available on the market in the form of transdermal devices are scopolamine, nitroglycerin, 17-beta-oestradiol, nicotine, and, for the future, forms containing fentanyl, timolol, ephedrine ... are currently being developed.

Administration, Cutaneous↗