Substitution Of Sucrose Research Articles

Collaborative WHO xylitol field studies in Hungary. IV. Saliva levels of Streptococcus mutans.

Salivary Streptococcus mutans was quantified to detect possible age-, sex-, and group-dependent differences at the end of a 3-year field study assessing the value of partial substitution of sucrose with xylitol (X group) in comparison with systemic administration of fluoride (F group) and restorative treatment solely (C group). The material of this substudy consisted of 390 institutionalized children aged 9-14 years. S. mutans was determined through the spatula technique and grouped into categories 0, less than 10(5), 10(5)-10(6), and and greater than 10(6) CFU/ml saliva. Zero to less than 10(5) values included more than 80% of the subjects of the X group. The cross-sectional comparison between groups showed lower S. mutans values in the X group than in the F and C groups. These differences between groups were highly significant. S. mutans was not dependent on age or sex.

Collaborative WHO xylitol field studies in Hungary. I. Three-year caries activity in institutionalized children.

The aim of this 3-year field study was to assess the value of partial substitution of sucrose with peroral xylitol (14-20 g/day) as a caries-preventive measure (X group) in comparison with systemic administration of fluoride (F group) and restorative treatment procedures solely (C group). An F dentifrice was used unsupervised in the X and F groups, the former containing 10% xylitol. The C group used customary, predominantly F-free dentifrices distributed by the local health authorities. The final material consisted of 689 institutionalized children (6-11 years). Caries was scored yearly in duplicate by two continuously calibrated teams. At base line the X group had a significantly higher caries prevalence than the F and C groups. The 3-year DMFS increment was 4.2 in the X group, 6.5 in the F group, and 7.7 in the C group. The corresponding ratio (RS) between caries incidence and the tooth surface population at risk was RSx, 4.9; RSF, 6.6; and RSC, 8.6. It is concluded that dietary xylitol in solid sweets resulted in a lower increment of caries than obtained in the F and C groups (p less than 0.001, covariance analysis, with base-line prevalence, number of permanent teeth, and visible plaque index as covariants).

Effect of sodium gradient on the rate of relaxation of rat mesenteric small arteries from potassium contractures.

We have measured the relaxation of rat mesenteric small arteries (internal diameter ca. 200 micron) from a potassium contracture under conditions where the transplasmalemmal sodium gradient was altered. Adjustment of the sodium gradient was made either by exposing vessels to ouabain (1 mM) for different periods to vary the intracellular sodium concentration (Nai), or by varying the sodium concentrations of the relaxation solutions (Nao). Under normal conditions (where we have previously shown Nai is about 19 mM), vessels relaxed completely within 1 min in low sodium solutions (Nao = 25 mM) using either sucrose, choline-Cl or MgCl2 as substitutes. However, the relaxation (measured after 1 min) was reduced when sucrose substitution was used, and further experiments were made using this substitute. Here it was found that exposing vessels to ouabain, for example 90 min (thus increasing Nai to about 73 mM) and then performing the relaxation in a low sodium solution gave only about 50% relaxation after 1 min. Experiments with intermediate sodium concentrations in the relaxation medium showed that reduction to 100 mM had no significant effect on the relaxation, and that it was only below 50 mM that effects were most marked. The effects of altered sodium gradient were eliminated if the calcium concentration of the relaxation medium was zero. The results indicate that under normal physiological conditions, small changes in sodium gradient have little effect on calcium metabolism of rat mesenteric small arteries, but also that under extreme conditions net calcium extrusion does appear to be reduced by a reduced sodium gradient.

Operation of internal Na-dependent Ca influx mechanism associated with catecholamine secretion in the adrenal chromaffin cells.

The cat adrenal gland was retrogradely perfused with a medium lacking divalent cation, and the secretion of catecholamines was induced by Ca reintroduction with or without simultaneous removal of external Na. These responses were markedly reduced after prior exposure to a medium containing Mg (1 mM) or lacking Na. The inhibition caused by Mg was reversed by ouabain treatment. Reversing the concentration gradient for Na alone by replacing external Na with Tris, choline, or Li did not stimulate catecholamine secretion when Ca2+ (0.1 mM) was present in the external medium throughout the experiment. However, the treatment with ouabain reversed this inhibitory effect of Ca so that Na removal did induce marked secretion. Essentially similar results concerning secretion were obtained in the cultured bovine chromaffin cells. There was a reasonable correlation between secretion and 45Ca uptake in these cells under various experimental manipulations, and alterations of these parameters were well correlated with the level of internal Na. Furthermore, the rate constant of 22Na efflux was found to increase when Ca was reintroduced with the simultaneous removal of Na during exposure to a medium containing ouabain. These results are consistent with the view that the mechanism of internal Na-dependent Ca influx is activated to induce catecholamine secretion whenever internal Na is raised above a critical level. On the other hand, there were significant increases in the catecholamine secretion and 45Ca uptake which were induced by substitution of NaCl with sucrose, even when the operation of the internal Na-dependent Ca influx mechanism was markedly restricted by various experimental manipulations. This suggests that other secretory mechanisms are involved under these conditions. This would account for the largest secretory effect of sucrose substitution under the condition in which internal Na-dependent Ca influx is activated.

Sucrose-induced insulin resistance in the rat: modulation by exercise and diet

Isocaloric substitution of sucrose for starch results in hyperinsulinemia and deterioration of glucose tolerance, suggesting a loss of insulin sensitivity. In this study we have quantitated the insulin resistance which develops with sucrose feeding, and evaluated the ability of dietary fiber, or an increase in skeletal muscle activity, to inhibit, or even prevent, the detrimental effect of sucrose feeding on in vivo insulin action. Thus, 6-wk-old rats were fed one of the following regimens for three weeks: a 64% cornstarch diet (C), a 32% cornstarch + 32% sucrose diet (S), the (S) diet containing added wheat bran fiber (S/F), and the (S) diet given to rats running spontaneously in exercise wheel cages (S/ET). Insulin sensitivity was evaluated by comparing steady-state plasma glucose (SSPG) concentrations at constant plasma insulin levels ∼70 µU/ml attained during the continuous infusion of epinephrine (0.08 µg/kg/min), propranolol (1.7 µg/kg/min), glucose (8 mg/kg/min), and insulin (2.5 mU/kg/min) to each experimental group. The results show that rats fed the S diet had a significant increase (p < 0.01) in mean (± SEM) SSPG concentration compared with rats fed the C diet (255 ± 14 versus 165 ± 3 mg/dl). SSPG concentrations, although lower (p < 0.05) in rats fed S/F (205 ± 8 mg/dl), were still higher (p < 0.05) than the C levels (165 ± 3 mg/dl). However, S/ET completely inhibited the increase in SSPG concentration seen in rats fed S and the values were actually lower (p < 0.05) than in rats fed C (100 ± 10 versus 165 ± 3 mg/dl). In conclusion 1) sucrose feeding results in a loss of insulin sensitivity in normal rats; 2) addition of fiber attenuates, but does not completely prevent, the loss of insulin sensitivity associated with feeding sucrose; 3) exercise training prevents the loss of insulin sensitivity seen in sucrose-fed rats, and actually improves glucose uptake beyond that seen in the control group. These results document the profound effect of environmental factors on in vivo insulin action.

A purified cariogenic diet for rats to test sugar substitutes with special emphasis on general health.

As a consequence of the partial substitution of sucrose by sugar alcohols in the cariogenic diets 580 or 2000, rats often suffer severe diarrhoea, resulting in retarded body weight gains, impaired gen

Ionic requirements for in vitro retrograde axonal transport of acetylcholinesterase

The ionic requirements for retrograde axonal transport of acetylcholinesterase were studied in vitro in desheathed spinal nerves of the bullfrog; the accumulation of enzyme activity distal to a ligature served to evaluate the status of retrograde transport. After an 18 h incubation in control medium, the 2 mm segment of nerve immediately distal to the ligature contained approximately twice as much acetylcholinesterase activity as other more distal segments. Accumulation of acetylcholinesterase distal to the ligature was reduced during incubation in Ca 2+-free medium plus 1 mM EGTA; retrograde transport was not diminished by the substitution of sucrose for the NaCl of the medium. In comparison with ionic requirements for orthograde fast axonal transport of protein, retrograde transport of acetylcholinesterase thus appears to share a Ca 2+ requirement, but not a requirement for NaCl.

The inhibitory effect of monensin on high K-induced contraction in guinea-pig taenia coli.

This study deals with the effects of monensin, a Na ionophore, on contraction, cellular Na content, oxygen consumption and tissue ATP content of smooth muscle of the guinea-pig taenia coli depolarized by high K (62.7 mM) solution. The application of monensin (10(-8) -10(-6) M) had little effect on the phasic component of the K contraction while it decreased the tonic component. The inhibitory effect of monensin, unlike that of verapamil, was not antagonized by raising the concentration of external Ca. Under hypoxic conditions, the inhibitory action of monensin (10(-7) M) was greatly reduced. The removal of Na (choline or sucrose substitution) from the high K solution did not attenuate the inhibitory effect of hypoxia or monensin. Monensin (10(-7) M) produced only a small increase in cellular Na in the depolarized muscle. The K-induced increase in the rate of oxygen consumption was suppressed by monensin (10(-6) M). In high K solution, but not in normal solution, monensin (10(-6) M) decreased the tissue ATP content. These results suggest that the relaxing action of monensin is mainly due to the inhibition of aerobic energy metabolism of the smooth muscle of guinea-pig taenia coli.

On the mechanism of the inhibition of fast axonal transport caused by exposure of frog spinal ganglia to a sodium-deficient medium

Substitution of choline or sucrose for Na + in the medium surrounding frog spinal ganglia causes an inhibition of fast axonal transport in vitro. Since an increased Ca 2+ influx into neurons does occur in these media, the present experiments examined the possibility that the effect on transport is mediated by an increase in intracellular free Ca 2+. The combination of the choline substitution with a 3-fold increase in extracellular Ca 2+ reduced transport of [ 3H]proteins to 75% of control (as compared to the 63% obtained previously with choline alone), thus providing no evidence of an enhancement of choline's effect by a second factor which promotes an increase in intracellular Ca 2+. When Li + was substituted for Na +, the quantity of [ 3H]proteins transported fell to 40% of control despite the fact that the Li + substitution does not modify Ca 2+ fluxes across the plasma membrane in neurons of the frog spinal nerve. The present findings suggest that removal of Na + interferes with fast axonal transport by a mechanism other than an increase in intracellular Ca 2+.

Effects of sodium gradient manipulation upon cellular calcium, 45Ca fluxes and cellular sodium in the guinea-pig taenia coli.

1. Sucrose and choline were utilized as NaCl substitutes in order to investigate Na-Ca interactions in the smooth muscle of the guinea-pig taenia coli.2. Progressive substitution of NaCl by sucrose caused a progressive increase in cellular exchangeable Ca. This uptake, which amounted to about 300 mumole Ca/kg tissue upon total Na replacement, reached a plateau within 20 min. Complete substitution of NaCl by choline chloride caused cellular Ca to increase rapidly to an initial peak, and then decrease to a stable plateau which was also about 300 mumole/kg above control.3. Replacement of NaCl by either sucrose or choline chloride caused a transient increase in the Ca influx rate, which was measured using a 3 min pulse labelling with (45)Ca. This increase was more pronounced in choline chloride.4. NaCl substitution by either sucrose or choline chloride caused a decrease in the (45)Ca efflux rate. Two exponential components of transmembrane (45)Ca efflux were found in control and Na-free media.5. Treatment of tissues with 3 x 10(-5)m-ouabain did not significantly affect the cellular Ca content after 80 min, at which time the Na and K gradients were largely dissipated.6. Removal of medium K caused a slower dissipation of the Na and K gradients. This treatment decreased cellular Ca, did not affect the Ca influx rate, and increased the (45)Ca efflux rate.7. Tissues were incubated in depolarizing media containing 10(-4)m-ouabain in order to remove the Na gradient. Subsequent measurement of cellular Na indicated the absence of a significant fraction of bound Na.8. The ratio [Na](o)/[Na](i) had a value of 6.3 in control medium, and decreased as [Na](o) was progressively lowered by sucrose substitution, reaching a value of < 1 in a medium containing 5 mm-Na.9. These experiments provide evidence that a Na-Ca exchange carrier does not play an important role in regulation of tension in this muscle, and also indicate that the Ca gradient is not solely dependent on the Na gradient in guinea-pig taenia coli.

Effects of prenatal ethanol exposure on avoidance conditioning in high-and low-avoidance rat strains

Two lines of rats selected for high- and low-avoidance performance consumed a nutritious liquid diet containing 35% ethanol-derived calories through days 5--18 of gestation. Control dams were pair-fed an identical liquid diet except for isocaloric substitution of sucrose for ethanol or ad libitum laboratory chow and water. Subsequently, the offspring of the low-avoider dams fed ethanol were found to be impaired ona two-way shock-avoidance conditioning when compared to the pair-fed and ad libitum controls from the same line. In contrast, the offspring of the high-avoider dams fed ethanol displayed similar levels of avoidance, responding to their controls. These results demonstrate that the effects on avoidance conditioning of in utero ethanol exposure are dependent upon the line of rat studied.

Prenatal ethanol exposure permanently reduces the number of pyramidal neurons in rat hippocampus.

The effect of prenatal ethanol exposure in the rat on the development of dorsal hippocampal pyramidal and dentate gyrus granule cells was examined. Ethanol was administered in a nutritionally adequate liquid diet to pregnant rats during days 10--21 of gestation. Control groups were either pair-fed the same liquid diet, except for equicaloric substitution of sucrose for ethanol, or received free access to pelleted laboratory food. The brains of 60-day-old offspring exposed to ethanol during gestation were found to have 20% fewer dorsal hippocampal pyramidal cells than did those of controls. Prenatal ethanol exposure, however, did not affect the number of dentate gyrus granule cells. Prenatal exposure to ethanol permanently reduced the number of prenatally formed hippocampal neurons without altering physical growth, which suggested that the developing nervous system is particularly sensitive to the toxic effects of ethanol.

Sodium-calcium exchange in mammalian myocardium: the effects of lithium

Studies were carried out to investigate the effect of lithium (Li) on mechanical function and on sodium (Na) and calcium (Ca) exchange in the isolated, arterially perfused interventricular septum of the rabbit. Perfusion of the septum with solutions containing zero potassium (0 K) and either 142 m m Na or 36 m m Na replaced by sucrose caused large increments in Ca uptake and the development of contracture. If, however, Li was substituted for Na instead of sucrose, both Ca uptake and contracture were markedly reduced. Despite the fact that Li substitution caused progressive loss of contracture, and sucrose substitution an increase of contracture (under 0 K perfusion conditions) neither substitution altered the rate of 45Ca efflux. 47Ca uptake experiments showed that substitution of Li for Na (no previous sucrose substitution) in 0 K perfusion, thereby producing an increase in [Na] i/[Na] 0 ratio, caused an increase in Ca uptake which reached a plateau within 30 min. However, when Li was substituted for sucrose (unchanged [Na] i/[Na] 0) the progressive net uptake of Ca associated with sucrose stopped immediately and a progressive net loss was induced. Three conclusions are drawn from these results: (1) Li blocks the contractures produced during a 0 K perfusion by decreasing both Ca uptake and Na efflux. (2) An increase in [Na] i/[Na] 0 ratio induces an initial contracture and increased Ca uptake. (3) The progression of contracture and Ca uptake is dependent upon continued operation of the NaCa exchange system. This does not occur in the presence of Li. The substitution of Li for Na separates two facets of the NaCa relationship: (1) the effect of [Na] 0 on superficial Ca-binding, (2) the effect of [Na] i on the NaCa “carrier”.

Characterization of α 2-adrenergic receptors on human platelets using [ 3H]yohimbine

Summary In order to investigate properties of alpha-adrenergic receptors of human platelets, we have examined the binding of [ 3 H]yohimbine, a potent α 2 -adrenergic 3 antagonist, to intact platelets and platelet membranes. There were 207±41 [ 3 H]yohimbine sites per platelet. These had an equilibrium dissociation constant (K D ) of 2.7 ± 0.7nM, a Hill coefficient of 1.02±0.11, and were competed for by adrenergic compounds stereoselectively and with a rank order expected at α 2 -adrenergic receptors. Addition of Na + and GTP synergistically decreased the affinity of epinephrine in competing for [ 3 H]yohimbine sites in platelet membranes and the resulting affinity of epinephrine in membranes was similar to that obtained with intact platelets. Substitution of sucrose for NaCl increased the affinity of epinephrine for intact platelets. [ 3 H]yohimbine thus appears to be a useful ligand for characterization of platelet α 2 -adrenergic receptors. Our results suggest that extracellular Na + and intracellular GTP and Mg ++ may be physiological determinants of epinephrine binding to these receptors.

Choline uptake by the neuroblastoma x glioma hybrid, NG108-15.

The neuroblastoma x glioma hybrid clone NG108-15 is able to release acetylcholine upon depolarization and form cholinergic neuromuscular synapses in culture. Normal functioning of cholinergic synapses is thought to be dependent on the ability of a neuron to take up extracellular choline, since neurons are unable to synthesize choline de novo. For these two reasons it became important to characterize the choline uptake system of NG108-15 cells. The uptake system appears to bear little if any resemblance to the Na+-dependent high-affinity choline uptake system normally associated with cholinergic neurons. Although the cells appear to possess both high- and low-affinity choline uptake systems, neither system is dependent on Na+ and uptake actually is increased about 60% by the substitution of sucrose for NaCl. Acetylcholine synthesis also is not dependent on Na+, since sucrose, substituted for NaCl, also stimulates acetylcholine synthesis. Changes in the concentrations of the other ions in the uptake medium have little effect on uptake, with the exception that elevated Ca2+ or Mg2+ reverses the stimulation of choline uptake produced by substitution of sucrose for NaCl. Choline uptake is inhibited by hemicholinium-3, but only at high concentrations of the drug (IC50 = 30-80 microM). The metabolic poisons cyanide and iodoacetate inhibit uptake by only 30-40%. Growth of the cells in N6,O2' dibutyryladenosine-3',5'-cyclic monophosphate, which promotes functional and morphological differentiation of the cells, decreased slightly the total amount of choline taken up but had no additional effect on the uptake system. Thus, it appears that NG108-15 cells are capable of forming functional cholinergic synapses with muscle cells even though the neuroblastoma does not possess the high-affinity choline uptake system normally associated with cholinergic neurons.

Biosynthesis of L-lysine in Corynebacterium glutamicum on sucrose, ethanol and acetic acid.

Production of L-lysine was followed in two lysine-accumulating mutants of Corynebacterium glutamicum ATCC 13287 in media containing sucrose, ethanol, acetic acid or a mixture of acetic acid and ammonium or sodium acetate. It was found that acetate is the best substitution for sucrose.

Electrical properties of individual cells isolated from adult rat ventricular myocardium.

1. Individual cells were isolated from adult rats ventricular myocardium by a collagenase digestion procedure. 2. Steady membrane potentials recorded with conventional intracellular glass micro-electrodes from cells in a modified Krebs solution containing 3 . 8 mM-KCl and 0 . 5 mM-CaCl2 were less negative than -40 mV in most cells (-25 . 3 +/- 10 . 9 mV, mean +/- S.D., 211 cells). 3. After addition of the potassium selective ionophore valinomycin (60 nM) to the bathing solution all recorded membrane potentials were more negative than -60 mV (-74 . 8 +/- 7 . 0 mV, sixty-three cells). 4. The internal concentration of potassium in the cells was determined as 120 . 8 +/- 1 . 7 mM (+/- S.E., n = 24) by flame emission spectrometry after centrifugation through silicone oil, using tritiated water and D-[1-14C] mannitol to estimate total and extracellular water in the pellet. 5. In the majority of cells in the standard solution the membrane potential recorded within a few msec of penetration was more negative than -70 mV (-78 . 4 +/- 9 . 7 mV, seventy-three cells). In sixty-six cells penetration initiated an action potential which overshot zero by 31 . 3 +/- 7 . 1 mV. This overshoot was abolished by reducing the external sodium to 0 . 1 of the normal value, and reduced or abolished by addition of tetrodotoxin (30 microM). 6. Modifications of the standard bathing solution which increased the number of cells with steady recorded membrane potentials more negative than -60 mV were: isosmotic substitution of sucrose for NaCl; replacement of NaCl and KCl by sodium isethionate and potassium methyl sulphate; addition of 5 or 10 mM-CaCl2; addition of 10 mM-MnCl2. 7. For cells in solution containing 2 . 5 or 5 . 5 mM-CaCl2, input resistances estimated from the amplitude of hyperpolarizations evoked by 200 msec current pulses were approximately 40 M omega at a resting potential close to -80 mV and became much greater as cells were depolarized. Time constants measured at the resting potential were approximately 8 msec. 8. In certain conditions, repeated spontaneous action potentials were recorded from contracting cells, and in quiescent cells evoked action potentials could be initiated by applying brief depolarizing pulses through the micro-electrode. Action potentials were coincident with contractions. 9. It is concluded that the resting potential of these isolated cells is normally more negative than -70 mV, and that the cells retain the ionic mechanisms necessary for the generation of active currents.

Moderate Sucrose Ingestion and Blood Pressure in the Rat

Four related hypotheses were tested: 1) substitution of sucrose for starch at moderate levels will significantly elevate blood pressure; 2) most urinary sucrose is endogenous; 3) a change in endogenous sucrose production will alter sodium excretion and blood pressure, and 4) dietary sucrose inhibits endogenous sucrose production. The systolic blood pressures of 25 male rats, 100 days of age, and 25 female rats, 1 year of age, were measured weekly for 8 months. In four experiments, they consumed diets in which 38% of energy came from fat, 15% from protein, 7% from lactose and the remaining 40% from five different sucrose/starch ratios. In experiment 4, a 10% maltose/30% starch diet was fed to one-half the rats fed sucrose in experiment 3. All rats were fed similar amounts of each diet so that there were no significant body weight differences between groups at the end of the 8 months. At periodic intervals all rats were injected with 1 micro c of [U-14C]glucose and placed in metabolism cages where a 24 hour urine sample was obtained. Urine was analyzed for sodium, sucrose and sucrose-14C content. Endogenous sucrose production was estimated from the percent of [U-14C]glucose recovered as urine sucrose-14C in 24 hours. All four hypotheses were confirmed.

Coupling Sugar&lt;sup&gt;&amp;reg;&lt;/sup&gt;の歯垢沈着に及ぼす影響について

The purpose of this investigation was to evaluate plaque accumulation on tooth surfaces in monkeys comparing sucrose with coupling sugar clinically and microbiologically. This coupling sugar was developed in substitution for sucrose in Japan.At first, clinical observation was performed. Ten monkeys were used and fed coupling sugar and sucrose. Dental deposits was stained by 0.5% basic fuchsin at 2, 4, 7 and 10 days. The standardized photographs of the tooth surfaces were taken by planimetric method. The plaque accumulation rate was analyzed by projecting the color slide on section paper. In the coupling sugar group, the accumulation rate of heavily stained plaque was less than that of the sucrose group. Though, no difference was found in total plaque accumulation rate between both groups.The second, two monkeys were employed for analyzing plaque microbiologically. The samples of the microbial plaque were taken at 4, 7 and 9 days on the labio-buccal tooth surfaces. Plaque samples were handled carefully and immediately dispersed in Manganiello's media and sonicated. Then, the suspension was dropped onto blood agar plates, MS-agar plates, MS-B agar plates, Actinomyces selective agar plates and Neisseria selective agar plates. The Neisseria selective agar plates were cultured aerobically. The other agar plates were cultured in Gas Pak jar anaerobically. The number of the colonies grown on the agar plates were counted. The number of Streptococcus mutans in coupling sugar group was less than in the sucrose group. There was, however, no difference between the two groups concerning total microorganisms, Streptococcus numbers, Actinomyces numbers and Neisseria numbers. Those results may be due to the action of such components of coupling sugar as maltose, glycosyl sucrose and maltosyl sucrose.

Effects of postnatal alcohol exposure on maternal nesting behavior in the rat

Seven female Wistar rats were fed a liquid diet containing Sustagen and ethanol through Days 1–17 of lactation. Six control females were pair-fed an identical liquid diet except for isocaloric substitution of sucrose for ethanol. Continuous monitoring of maternal nesting behavior, employing automated nesting chambers, indicated that the mothers fed ethanol spent more time on the nest nursing their young than the pair-fed controls during the middle of the observation period. This increase in nesting time may be due to a decrease in activity in the ethanol-fed mothers or due to greater heat loss in their pups, allowing them to remain longer on the nest. This increased nesting time occurs when the pups’ motor effectiveness and exploratory drive are developing, and may account for the long-term behavioral changes seen in the pups.