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Enhancement of drug absorption by antacids. An unrecognised drug interaction.

Antacids are widely used for many disorders. The potential of antacids to interact with other concomitantly ingested drugs is well recognised. These interactions usually result in reduced or delayed absorption of the affected drug. However, this is not always the case. In contrast to aluminium hydroxide, magnesium hydroxide and sodium bicarbonate can enhance the absorption of some drugs. For example, magnesium hydroxide can increase the rate and sometimes even the extent of absorption of certain nonsteroidal anti-inflammatory drugs (e.g. tolfenamic acid, mefenamic acid and ibuprofen), sulphonylurea antidiabetic agents [e.g. glipizide, glibenclamide (glyburide) and tolbutamide] and the oral anticoagulant dicoumarol (bishydroxycoumarin). These weakly acidic drugs are nonionised at gastric pH, but are sparingly water soluble. Elevation of the gastric pH by administration of magnesium hydroxide or sodium bicarbonate increases the solubility and absorption of such sparingly water soluble agents. Chelate formation may be involved in the increased absorption of dicoumarol by magnesium hydroxide. In combination antacids containing both aluminium hydroxide and magnesium hydroxide, the absorption enhancing effect of magnesium hydroxide seems to be counterbalanced by the opposing effects of aluminium hydroxide. The clinical significance of increased drug absorption is not clear. However, accelerated and enhanced absorption of analgesic drugs may be beneficial when rapid pain relief is desired. In contrast, an unexpectedly increased hypoglycaemic or anticoagulant effect may be potentially dangerous. Therefore, a knowledge of the potential effect of antacids on the absorption of other drugs is clinically important.

Absorption↗

Effects of increased ureteropelvic pressure on fluid and NaCl absorption across the jejunum.

The aim of the present study was to elucidate the effects of an increased ureteropelvic pressure (UPP) on the net jejunal fluid, Na+, and Cl- absorption in anesthetized dogs. UPP was changed under hydrostatic pressure with warmed Ringer's solution. At a UPP of 0 mmHg, the net jejunal fluid, Na+, and Cl- absorption were 10.1 +/- 0.5 ml, 2.4 +/- 0.1, and 2.0 +/- 0.1 mEq, and were significantly reduced to 5.9 +/- 0.4 ml, 2.0 +/- 0.1, and 1.6 +/- 0.1 mEq, respectively, by an increase in UPP to 60 mmHg. After lowering the UPP to 0 mmHg, the net absorption recovered to the control values. The same experiments were performed after ipsilateral renal denervation. Ipsilateral renal denervation completely abolished this response. This result suggests that the afferent pathway of this response is the renal nerves. We also assessed the validity of the method using a jejunal loop by examining the effects of repetition of the absorption experiment on the net absorption. The net absorption was not altered by 6 times repetition of the absorption experiment. To determine the collection ratio, phenol red was used in the first and sixth absorption experiments. The collection ratios were 92.2 +/- 1.1 and 90.3 +/- 0.9%, respectively. There was no significant difference in collection ratio between the first and sixth values. This is the first report in which an increased UPP was found to inhibit the net jejunal fluid, Na+, and Cl- absorption.

Animals↗

Cholesterol absorption and synthesis in children with type 1 diabetes.

OBJECTIVE: The levels of the surrogate markers of cholesterol absorption (cholestanol and plant sterols) and synthesis (cholesterol precursors) in serum have suggested that in adult type 1 diabetes, cholesterol absorption is high and synthesis is low compared with type 2 diabetic or control subjects. Accordingly, these findings were further studied in children with type 1 diabetes. RESEARCH DESIGN AND METHODS: Forty-eight children with diabetes were compared with 79 age- and sex-matched control subjects. The serum ratios of cholesterol absorption and synthesis markers were measured with gas-liquid chromatography. The study population was divided into triads (combining the two lowest triads) by serum cholestanol ratios of the control subjects indicating low to high cholesterol absorption efficiency. RESULTS: The ratios of the absorption and synthesis markers were similar in case and control subjects, and they were negatively related to each other in control subjects, being less consistent in diabetic patients. Thus, high cholesterol absorption was associated with low synthesis. Plant sterol ratios increased significantly with increasing cholestanol triads in both groups, but the values in the lowest triads were higher in case versus control subjects. CONCLUSIONS: Homeostasis between cholesterol absorption and synthesis is maintained in control children and somewhat less consistently in those with diabetes. The higher plant sterol ratios in diabetic versus control subjects in the lowest cholestanol triads suggest that cholesterol absorption is higher in children with diabetes versus control subjects but only within the range of low cholesterol absorption.

Absorption↗

Absorption kinetics and biologic effects of subcutaneously injected insulin preparations.

This paper describes systematic studies on the absorption kinetics of exogenous insulin from its subcutaneous tissue depot in 52 male nonobese volunteers (age 20-30 yr). Five experimental protocols were used: effect of changing injection site, effect of temperature change and local massage, effect of aprotinin and human serum, effect of mixing regular insulin with long-acting insulin preparations, and effect of temperature change, muscular exercise, and local massage on the absorption of long-acting insulin preparations. The fastest absorption of insulin occurred at the abdominal injection. Absorption after arm injection was faster than after thigh injection. A hot bath and local massage dramatically increased serum insulin levels in the first 90 min after injection; in contrast, a cold bath delayed absorption substantially. Both aprotinin and the subjects' own blood serum mixed with insulin caused a marked acceleration of the insulin absorption process. Absorption kinetics of two neutral regular insulins (Actrapid and Leo Regular) were virtually identical. Mixing Actrapid with Monotard caused higher serum insulin levels than the mixture of Leo Regular with NPH. A time lag of 5 min between the mixing of Actrapid and Monotard and the injection caused a delayed rise of serum insulin levels; in contrast, this delay could not be observed when Leo Regular and NPH were mixed. Volunteers performed bicycle exercise, applied a hot water bottle to the injection site, or rubbed the injection site 2 1/2 h after injection of long-acting insulin. Accelerated absorption of insulin was only observed after local massage of the injection site of Monotard, Leo NPH, and Mixtard. Local heat had no effect. Exercise caused only an increased absorption of insulin after the Mixtard injection but not after Monotard or NPH injection. These findings have clinical significance and should not be without potential benefit in the attempt to improve metabolic control in insulin-treated diabetic patients.

Adult↗

Effect of increasing ruminal butyrate absorption on splanchnic metabolism of volatile fatty acids absorbed from the washed reticulorumen of steers.

Four steers fitted with a ruminal cannula and chronic indwelling catheters in the mesenteric artery, mesenteric vein, hepatic portal vein, hepatic vein, and the right ruminal vein were used to study the absorption and metabolism of VFA from bicarbonate buffers incubated in the temporarily emptied and washed reticulorumen. Portal and hepatic vein blood flows were determined by infusion of p-aminohippurate into the mesenteric vein, and portal VFA fluxes were calibrated by infusion of isovalerate into the ruminal vein. The steers were subjected to four experimental treatments in a Latin square design with four periods within 1 d. The treatments were Control (bicarbonate buffer) and VFA buffers containing 4, 12, or 36 mmol butyrate/kg of buffer, respectively. The acetate content of the buffers was decreased with increasing butyrate to balance the acidity. The butyrate absorption from the rumen was 39, 111, and 300 +/- 4 mmol/h for the three VFA buffers, respectively. The ruminal absorption rates of propionate (260 +/- 12 mmol/h), isobutyrate (11.4 +/- 0.7 mmol/h), and valerate (17.3 +/- 0.7 mmol/h) were not affected by VFA buffers. The portal recovery of butyrate and valerate absorbed from the rumen increased (P < 0.01) with increasing butyrate absorption and reached 52 to 54 +/- 4% with the greatest butyrate absorption. The liver responded to the increased butyrate absorption with a decreasing fractional extraction of propionate and butyrate, and with the greatest butyrate absorption, the splanchnic flux was 22 +/- 1% and 18 +/- 1% of the absorbed propionate and butyrate, respectively. The increased propionate and butyrate release to peripheral tissues was followed by increased (P < 0.05) arterial concentrations of propionate (0.08 +/- 0.01 mmol/kg) and butyrate (0.07 +/- 0.01 mmol/kg). Arterial insulin concentration increased (P = 0.01) with incubation of VFA buffers compared with Control and was numerically greatest with the greatest level of butyrate absorption. We conclude that the capacity to metabolize butyrate by the ruminal epithelium and liver is limited. If butyrate absorption exceeds the metabolic capacity, it affects rumen epithelial and hepatic nutrient metabolism and affects the nutrient supply of peripheral tissues.

Absorption↗

Effect of potassium level on site of absorption of magnesium and other macroelements in sheep.

Eighteen wether lambs, surgically equipped with abomasal and ileal cannulae, were used in two metabolism trials. Two levels of dietary Mg (.1 and .2%) and three levels of K (.6, 2.4 and 4.8%, dry basis) were fed with a 2 x 3 factorial arrangement. Each trial consisted of a 10-d preliminary period, a 7-d collection of feed, feces and urine for determining mineral balance and a 6-d sampling of feed, abomasal and ileal fluid and feces to determine flow and site of mineral absorption. Magnesium absorption occurred before the small intestine. Feeding 2.4 and 4.8% K decreased (P less than .05) Mg absorption by 24.4 and 61.2%, respectively. Preintestinal absorption of Mg was depressed linearly with increases in dietary potassium. Larger amounts of Mg flowed to the small intestine and were excreted in the feces when the high level of Mg was fed. A net secretion of Mg into the small intestine followed by a small amount of Mg absorption in the large intestine was also found. Serum Mg was depressed 7 and 10% when diets containing 2.4 and 4.8% potassium were fed, respectively. Magnesium level did not affect K absorption or balance. Potassium absorption, retention and urinary excretion increased (P less than .05) with increasing K level. Animals fed the low K diet had a negative absorption of K preintestinally with the small intestine being the main site of absorption. Increasing K level resulted in approximately equal amounts of K being absorbed in the stomach and small intestine.

Animals↗

Influence of diet composition on intestinal volatile fatty acid and nutrient absorption in unanesthetized pigs.

Two experiments were conducted to study the effect of the amount and nature of fiber and carbohydrates on nutrient and VFA absorption. Five Large White pigs in each crossover experiment were accustomed to a semisynthetic 14% protein diet containing 6 (LC) or 16% (HC) pure cellulose (Exp. 1) or 22% alfalfa meal (6.3% cellulose, HA) and 22% lactose and 6% pure cellulose (HL; Exp. 2). Each animal was then fitted with catheters in the portal vein and carotid artery and with a flow probe around the portal vein. Eight days after surgery, the absorption of reducing sugars (RS) and amino-N was studied for 12 h and that of VFA for 24 h after intake of a single 800-g meal. The alternate diet was then given for 7 to 10 d and a second series of samplings was performed within the same conditions. In the first experiment, added dietary cellulose decreased efficiency of absorption of RS (LC: 90.4 +/- 7.0%; HC: 81.6 +/- 3.6%) and amino-N (LC: 95.3 +/- 9.1%; HC: 70.3 +/- 2.8%; P less than .05). Daily absorption (24 h) of VFA tended to be larger when the cellulose level rose (LC: 1,184 +/- 85 mmol; HC: 1,429 +/- 216 mmol, NS) and increased (P less than .05) with the length of adaptation (21 to 28 d) to the diet, regardless of cellulose level. In the second experiment, after intake of the alfalfa diet, absorption of RS was high (97.8%), whereas absorption of amino-N (74.3%) and VFA (880 +/- 87 mmol/24 h) were low. Intake of lactose reduced absorption of RS (85.2%), did not alter absorption of N (75.9%) and increased absorption of VFA (1,181 +/- 218 mmol/24 h). Thus, the energy efficiency of the diet was lowered (P less than .05) when cellulose was added to the diet but not when alfalfa meal or lactose were added.

Animals↗

Effect of perimenopause on calcium absorption: a longitudinal study.

OBJECTIVE: Cross-sectional studies suggest that the rise in calcium requirement at the menopause may be attributable, at least in part, to a fall in intestinal calcium absorption. The aim of the present study was to determine the effect of the menopause on intestinal calcium absorption and the relationship between any change in calcium absorption and serum calcitriol. METHODS: Radiocalcium absorption and serum calcitriol were measured in 72 women aged 47.3 (standard error, SE 0.19) years who were initially premenopausal (as judged by menstrual history and serum follicle stimulating hormone (FSH)) and again 18 months later. RESULTS: Calcium absorption fell at the second visit from 0.72 (0.029)/h to 0.64 (0.029)/h (p = 0.003). Serum calcitriol had also fallen at the second visit from 124 (4.2) pmol/l to 111 (4.0) pmol/l (p = 0.007). At that visit, serum FSH exceeded the premenopausal reference range in 11 subjects and the menstrual cycle had become irregular in 24 of them. In the 11 women with raised FSH at the second visit, radiocalcium absorption fell from 0.85/h (0.097) at baseline to 0.57/h (0.049) (p = 0.008), but only from 0.70/h (0.028) to 0.65/h (0.033) (not significant) in the remaining 61. Similarly, radiocalcium absorption fell significantly (p = 0.003) in the 24 women with irregular menses, but not in the remaining 48 who continued to menstruate regularly. These changes in calcium absorption were still significant after correction for changes in calcitriol levels. CONCLUSION: The perimenopause is associated with a fall in calcium absorption, which is only in part attributable to a fall in calcitriol levels.

Adult↗

The large intestine compensates for insufficient calcium absorption in the small intestine in rats.

We previously demonstrated that the large intestine compensated for decreased calcium (Ca) absorption caused by renal failure in rats fed a highly fermentable dietary fiber. In this study, we examined whether the large intestine compensated for insufficient Ca absorption in the rat small intestine without ingestion of a fermentable dietary fiber. Rats were fed one of four test diets containing either insoluble (carbonate) or soluble (gluconate, lactate, or citrate) Ca sources. The dietary Ca level was 2.0 g/kg, which is lower than the minimum requirement for rats (3.0 g/kg), to conduct the present study under a condition in which rats can maximally absorb Ca. To prevent Ca absorption in the small intestine, we replaced a primary phosphate (KH2PO4) with secondary phosphates (K2HPO4 and Na2HPO4) in diets. The apparent Ca absorption in the small intestine was estimated by adding chromic oxide (Cr2O3) as an insoluble and an unabsorbed marker to test diets and by measuring the ratio of Ca:Cr in the cecal content. The apparent Ca absorption in the whole intestine was estimated by the intake and fecal excretion of Ca. The apparent Ca absorption in the small intestine was significantly lower from the Ca carbonate diet than from the Ca gluconate, lactate, or citrate diets. The apparent Ca absorption in the whole intestine was not significantly different among the four groups, and the values were similar to the absorption rates in the small intestines of rats fed diets containing soluble Ca sources. These results show the following: (a) In rats fed 0.2% Ca diets containing soluble Ca salts, Ca is mostly absorbed in the small intestine, even in secondary phosphate intakes; (b) In contrast, in rats fed a 0.2% Ca diet containing an insoluble Ca salt (carbonate), Ca is not sufficiently absorbed in the small intestine. However, the large intestine compensates for the small intestinal Ca absorption decreased by dietary secondary phosphates.

Animals↗

Intestinal absorption of glucose and amino acids in chickens administered monensin.

Effects of the ionophoric anticoccidial agent monensin on glucose and amino acid absorption were investigated in young broiler chickens. Chicks housed in cages with wire floors were fed a practical diet containing 0 or 121 ppm monensin for 2 to 3 weeks prior to measurement of nutrient absorption. Chicks were anesthetized with halothane, and the intestine was accessed through an incision in the abdominal wall. A 10-cm segment of the intestine immediately anterior to Meckel's diverticulum was rinsed free of digesta and used for measurement of absorption in situ. One milliliter of saline solution containing 2 mM of glucose or a mixture of amino acids was injected into the lumen of the ligated segment, and recovery of glucose and amino acids in the lumen was determined after 4- and 5-min intervals, respectively. In one glucose study, the solution contained 0, 1, 10, or 80 micrograms/ml of monensin. In one amino acid study, the solution contained 0, 5, or 80 micrograms/ml of monensin; in subsequent studies, monensin was not included in the solution. Results show that neither dietary monensin nor monensin in the saline solution affected glucose absorption. Dietary monensin tended to depress lysine absorption but increased the absorption of tryptophan and arginine, the latter amino acid being markedly affected by monensin. Dietary monensin alone had no effect on absorption of cystine, isoleucine, methionine, or threonine. Inclusion of monensin in the saline solution depressed methionine absorption but only when birds also had been fed the diet containing monensin. Monensin in the saline solution depressed isoleucine absorption irrespective of dietary treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗

Ferritin iron absorption in man.

The iron absorption from ferritin and hemosiderin biosynthetically labeled with radioiron was studied in 108 subjects. The geometric mean absorption of ferritin iron in both normal and iron-deficient subjects was 1.9 percent. Its mean absorption ranged from 0.9 percent in normal subjects to 2.5 percent in subjects with moderate iron deficiency and 5.7 percent in subjects with marked iron deficiency. The administration of this iron compound with vegetals in a meal showed distinctly lower absorption values than the absorption from either maize, wheat, or soybean. Ferritin iron absorption was also different from that of ferric chloride when they were administered together as a drink or mixed with maize or liver. The iron absorption from ferritin was markedly increased when it was administered with either meat or liver, but it did not reach the absorption level of these foods. It is still to be elucidated whether the difference in iron absorption between ferritin and vegetable foods administered together reflect that this iron is incompletely miscible with a nonheme iron pool or that it really forms a third iron pool.

Administration, Oral↗

Absorption of morphine, butylscopolamine, mecamylamine and phenobarbitone from the small intestine of the triparanol-treated rat in situ.

The absorption of three basic drugs (morphine, butylscopolamine and mecamylamine) and an acidic drug (phenobarbitone) from the rat small intestine in situ was investigated by using a single perfusion technique. The effect of intestinal damage on absorption was studied by treating rats with triparanol 25-50 mg/kg every 24 h for three weeks. Treatment with triparanol decreased the cholesterol concentration in the intestinal wall. The absorption of morphine and mecamylamine was increased by treatment with triparanol, whereas the absorption of butylscopolamine was decreased and that of phenobarbitone remained unaltered. Treatment with triparanol decreased the concentration of mecamylamine in the intestinal wall, but the concentrations of other drugs were unchanged. When comparing the present in situ and previous in vitro results the decreased absorption of butylscopolamine after triparanol in situ was opposite to the finding in vitro. The increased absorption of morphine and unaltered absorption of phenobarbitone were in accordance with the finding in vitro. In situ the absorption of mecamylamine was increased, although in vitro it was unchanged. The structural damage, differences in composition of the intestinal wall and intestinal blood flow are supposed to be the reasons for changes in absorption.

Animals↗

[Comparative study of the effect of free and combined glucose and fructose on the absorption and retention of calcium].

Many carbohydrates play an important role in the process of absorption of several inorganic compounds, particularly of calcium, as shown by FOURNIER. VAUGHAN and FILER have proved that all carbohydrates are equally active under particular conditions: the difference of their action on calcium absorption is related to their absorption speed rate. Fructose appears in an intermediate situation between rapidly and slowly absorbed oses according to Cori's classification based on rates of absorption. In order to examine more closely the extent of differences of carbohydrates on calcium absorption, we chose to compare the action of free and combined fructose with that of carbohydrates found in normal feeding. Six months old rats in a state of calcium equilibrium received orally 2 ml aquous mixture containing 0,01 mM/ml calcium supplemented by 0,12 mu Ci 45 Ca and 0,075 mM/ml carbohydrate. The rats were divided into groups according to the carbohydrate they received, which was one of the following: D-glucose, D-mannose, D-fructose, L-sorbose, maltose, lactose, sucrose, starch, glycogen or inulin. Both absorption and retention of calcium were observed. A coefficient of absorption of 45Ca and the specific radioactivity of bone were established by the measurements of radioactivity of blood samples, which were taken 1 1/2 hour, 3 hours and 24 hours after ingestion, of intestinal content and feces, and of a femur after nitroperchloric mineralization. The results showed that values of absorption coefficient and of specific radioactivity are high for slowly absorbed sugars (mannose, sorbose, lactose) but are very low for free glucose or for glucose easily released by intestine enzymatic activity. Free fructose possesses in intermediate activity equivalent to that of inulin. However, sucrose administered at the same concentration has little effect on calcium absorption.

Absorption↗

Effect of bile salts and fatty acids on the colonic absorption of oxalate.

These studies were designed to evaluate the effect of bile salts and fatty acids on colonic oxalate absorption. Five millimolar deoxycholate significantly increased oxalate absorption from 34.2 +/- 9.4 nmoles per min per g dry weight to 330.4 +/- 47.3 (P less than 0.001) and changed water absorption to water secretion. Deoxycholate also increased the absorption of urea, decreased the electrical potential difference, and increased colonic clearance of oxalate, observations which are consistent with an increase in colonic mucosal permeability. In contrast, taurocholate did not increase oxalate absorption. Ricinoleic acid also significantly increased the absorption. These results suggest that bile salts and fatty acids increase colonic absorption of oxalate. Oleic acid had similar effects on oxalate absorption but was less effective than ricinoleic acid. Octanoic acid, a medium chain fatty acid, did not alter oxalate absorption of oxalate by a nonspecific alteration of mucosal permeability. These observations may further explain many of the clinical phenomena associated with enteric hyperoxaluria.

Animals↗

Absorption properties of alternative chromophores for use in laser tissue soldering applications.

The feasibility of using alternative chromophores in laser tissue soldering applications was explored. Two commonly used chromophores, indocyanine green (ICG), and methylene blue (MB) were investigated, as well as three different food colorings: red #40 (RFC), blue #1 (BFC), and green consisting of yellow #5 and blue #1 (GFC). Three experimental studies were conducted: (i) The absorption profiles of the five chromophores, when diluted in deionized water and when bound to protein, were recorded; (ii) the effect of accumulated thermal dosages on the absorption profile of the chromophores was evaluated; and (iii) the stability of the absorption profiles of the chromophore-doped solutions when exposed to ambient light for extended time periods was measured. The peak absorption wavelengths of ICG, MB, RFC, and BFC, were found to be 805 nm, 665 nm, 503 nm, and 630 nm respectively in protein solder. The GFC had two absorption peaks at 426 nm and 630 nm, corresponding to the two dye components comprising this color. The peak absorption wavelength of ICG and MB was dependent on the choice of solvent (deionized water or protein). In contrast, the peak absorption wavelengths of the three chromophores were not dependent on the choice of solvent. ICG and MB showed a significant decrease in absorbance units with increased time and temperature when heated to temperature up to 100 degrees C. A significant decrease in the absorption peak occurred in the ICG and MB samples when exposed to ambient light for a period of 7 days. Negligible change in absorption with accumulated thermal dose up to 100 degrees C or light dose (over a period of 84 days) was observed for any of the three food colorings investigated.

Absorption↗

[A study on absorption and utilization of calcium, iron and zinc in mineral-fortified and dephytinized soy milk powder consumed by boys aged 12 to 14 years].

OBJECTIVES: In order to understand the absorption and utilization of calcium, iron and zinc in cow milk, soy milk powder and dephytinized soy milk powder in the children and adolescents, and to lay a foundation for the improvement of protein and mineral nutrition in Chinese residents with popularizing consumption of soy milk powder. METHODS: Totally, 57 boys aged 12 to 14 years were selected and divided into three groups, matched by age, hemoglobin concentration, height and weight. The boys were given 220 ml of fortified and dephytinized soy milk, soy milk or cow milk, respectively, containing calcium 270 mg, iron 4 mg and zinc 4 mg, which were labeled with stable isotopes (44)Ca, (58)Fe and (70)Zn in a single serving size, and their feces were labeled with brilliant blue and dysprosium. Feces specimens were collected for all the subjects and absorption rate of calcium, iron and zinc were measured for all the children who took fortified and dephytinized soy milk, soy milk or cow milk, respectively. Calcium in feces was measured with heat ionized mass spectrometry, and recovery of (58)Fe and (70)Zn in feces and content of dysprosium were measured with induction coupling iso-ionic mass spectrometry, and then absorption rates of iron and zinc were calculated and adjusted by the recovery rate of dysprosium. RESULTS: Iron absorption rate was (6.7 +/- 3.8)% in soy milk powder group, (15.5 +/- 9.2)% in the cow milk group and (20.6 +/- 7.3)% in dephytinized soy milk powder group, respectively. Calcium absorption rate was (43.5 +/- 10.7)%, (64.2 +/- 11.4)%, and (50.9 +/- 6.6)% in the three groups, respectively. Absorption rate of zinc was (11.3 +/- 6.5)%, (31.2 +/- 10.4)% and (20.1 +/- 7.4)%, respectively. Significant increase in absorption of calcium, iron and zinc was observed in the groups with fortified and dephytinized soy milk powder, as compared with those consuming nondephytinized soy milk powder. Absorption rate of calcium and zinc was significantly higher in the group with cow milk than that in the group with dephytinized and fortified soy milk powder, and iron bioavailability was lower in the group with cow milk than that with dephytinized soy milk powder, with no significant difference. Absorption rates of calcium, iron and zinc were higher in children of China due to their long term adaptation to dietary intake of lower mineral and protein, and higher fiber. CONCLUSIONS: Bioavailability of calcium, iron and zinc in soy milk powder could be increased by dephytinized treatment for it.

Absorption↗

[Dust absorption effect of urban conifers in northeast China].

Dust pollution is much heavier in winter than in other seasons in the cities of Northeast China, because the urban heating system consumes mainly coal as energy resources. Deciduous trees can hardly absorb dust because of their defoliation, and hence, urban conifer trees become more important in dust absorption in winter. This paper studied the dust absorption ability of 7 conifers under the same and different dust pollution status in Shenyang city, Northeast China. The results showed that the dust absorption ability of conifers was decreased in the order of Abies holophilla > Picea mongolica > P. koraiensis > Taxus cupidata > Pinus bungeana > P. armandi > P. tabulaeformis. Different conifers had different surface structures. Pinus bungeana, P. armandi and P. tabulaeformis had smooth surfaces, their cells and stomata arranged in order, and hence, their dust absorption ability was poor. P. koraiensis, Abies holophilla and Taxus cupidata had coarse surfaces, and their cells and stomata arranged out of order. There were even many tubercular things on the surface of P. koraiensis, and hence, their dust absorption ability was stronger. The dust absorption ability of conifers was related the shape of their leaf sections. The upper leaf surface of Pinus bungeana and P. tabulaeformis was arc, not opted to absorb the dust. The leaf section of P. armandi was prism, and its upper surface was narrow, and hence, its dust absorption ability was also poor. The leaves of Picea mongolica and P. koraiensis had four edges, their upper surfaces were broader and flatter than the former three species, and hence, they had stronger dust absorption ability. The leaf section's shape of Abies holophilla and Taxus cupidata was also broad and flat, which made the dust absorption ability of the two latter's was stronger than other three Pinus species and two Picea species.

Absorption↗

Subcutaneous absorption of insulin in insulin-dependent diabetic patients. Influence of species, physico-chemical properties of insulin and physiological factors.

One major problem encountered when treating diabetic patients with insulin is the very large inter- and intra-individual variability in subcutaneous insulin absorption, a major contributory factor in the variability of the blood glucose level. Thus, to optimize insulin treatment the factors influencing the absorption have to be known and possibly utilized. The different types of insulin ("short-acting", "intermediate-acting" and "long-acting") have different times of action. "Short-acting" and "intermediate-acting" human insulin are probably absorbed slightly faster than porcine (and bovine) insulin. "Long-acting" human insulin is absorbed significantly faster than bovine insulin. More concentrated "short-acting" insulin (100 IU/ml) is absorbed slightly slower than less concentrated insulins (40 IU/ml). The absorption of "intermediate-acting" and "long-acting" insulin is dose-dependent, with a decreasing absorption rate with increasing dose of insulin. Insulin is administered subcutaneously either by injection or by using an infusion pump. The injection technique influences the absorption rate. Giving a continuous subcutaneous insulin infusion as a basal rate infusion, a depot is built-up. The building-up and the size of the depot, as well as the blood glucose and plasma insulin levels during steady-state conditions, are independent of the pulse-rate interval of the pump used (5 min vs 1 h). The size of the steady-state depot is constant during constant conditions but inversely correlated to the local subcutaneous blood flow and directly correlated to the infusion rate. An increase or decrease in the infusion rate during a basal rate infusion will after a delay of 2-3 h induce corresponding changes in the insulin absorption rate from the depot. After termination of the infusion, the insulin depot will still provide some insulin supply for 2-3 h. During the continuous infusion, the pharmacokinetics of the superimposed preprandial boluses will resemble injections of soluble insulin. The inter- and intra-individual variability in the insulin absorption, even when giving the same type, species, concentration and dose of insulin, is presumably primarily due to different and changing diffusion conditions in the subcutaneous tissue. Some factors which influence the diffusion conditions include exercise, local massage and, especially, local subcutaneous blood flow. Alterations in the blood flow induce, with a hyperbolic relationship, changes in the same direction in the absorption rate of injected and infused "short-acting" insulin and of injected "intermediate-acting" insulin. Several factors have been shown to influence both subcutaneous blood flow and insulin absorption, e.g. injection site, skinfold thickness, smoking, orthostatic changes, ketosis and ambient temperature.(ABSTRACT TRUNCATED AT 400 WORDS)

Absorption↗