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At least 199 records · Page 11Linked to original sources
PubMed2004

Nutritional homeostasis in carnivorous southern catfish (Silurus meridionalis): is there a mechanism for increased energy expenditure during carbohydrate overfeeding?

In previous growth experiments with carnivorous southern catfish (Silurus meridionalis), the non-fecal energy lose was positively related to dietary carbohydrate level. To test whether metabolic energy expenditure accounts for such energy loss, an experiment was performed with southern catfish juveniles (33.2-71.9 g) to study the effect of dietary carbohydrate level on fasting metabolic rate and specific dynamic action (SDA) at 27.5 degrees C. The fasting metabolic rate in this catfish was increased with dietary carbohydrate level, and the specific dynamic action (SDA) coefficient (energy expended on SDA as percent of assimilated energy) was not affected by dietary carbohydrate level. The results suggest that in southern catfish, carbohydrate overfeeding increases metabolic rate to oxidize unwanted assimilated carbohydrate. A discussion on the poor capacity of intermediate metabolism for adapting dietary carbohydrate in carnivorous fish and its possible relationship with facultative component of SDA was also documented in this paper.

Animals↗
PubMed2005

The selection of mixed microbial inocula in environmental biotechnology: example using petroleum contaminated tropical soils.

The impact of inorganic N and P additions on a tropical soil contaminated with petroleum hydrocarbons was investigated using molecular and culture techniques. Microcosms were incubated for 42 days and sampled at 0, 1, 7, 28 and 42 days. Changes in bacterial community structure were determined using denaturing gradient gel electrophoresis (DGGE) of the rRNA following reverse transcription PCR using primers specific to the V3 region of the 16S rRNA gene. To identify which components of the microbial community were changing during incubation, PCR amplicons were resolved using DGGE and the banding patterns analyzed using stepwise discriminant function analysis (SDA). SDA showed that the number of bands needed to recover the differences between samples over time could be reduced from the initial 11 bands for the 16S rRNA transcript to 3 bands. Sequences originating from the rRNA gels (16S rRNA transcripts) were recovered in clades containing known cultured isolates of Bacillus marisflavi, Microbacterium oxydans and Pseudomonas oleovorans. Isolation studies on these soils using lubricant oil as a carbon source yielded 317 bacterial isolates, 3 of which showed high sequence similarity (>96%) with the 16S rRNA transcripts identified using SDA as being important in differentiating between bacterial communities over time. These isolates were then tested singly and in combination for their ability to degrade lubricant oil. These analyses demonstrated that the consortium selected using the combined molecular-SDA approach was more effective at degrading the lubricant in both liquid media and in contaminated sand than the single isolates.

Bacteria↗
PubMed2004

Subdiaphragmatic vagal deafferentation fails to block the anorectic effect of hydroxycitrate.

We investigated the neural mediation of the feeding suppression through orally administered hydroxycitrate (HCA) in male rats that were fed a high-glucose diet (about 48% glucose). Ten-day ad libitum food intake and body weight regain after previous body weight loss (13% of initial body weight) due to restrictive feeding were measured in rats with sham deafferentation (SHAM; n = 6), subdiaphragmatic vagal deafferentation (SDA; n = 7), and SDA plus celiac-superior mesenteric ganglionectomy (SDA/CGX; n = 9). HCA suppressed the 10-day cumulative food intake in all surgical groups and body weight regain in SDA and SDA/CGX groups. Independent of HCA, SDA and SDA/CGX rats consumed less food and gained less weight compared to SHAM rats. These results demonstrate that all vagal afferents from below the diaphragm and vagal efferents of the dorsal trunk as well as splanchnic nerves (afferents and efferents) are not necessary for the feeding-suppressive effect of HCA in this animal model. Vagal afferents, however, appear to play a role in the control of intake when a high-glucose diet is consumed after a period of restrictive feeding.

Animals↗
PubMed2004

Projection from the ventral bed nucleus of the stria terminalis to the retrorubral field in rats and the effects of cells in these areas on mating in male rats versus gerbils.

This research identified the rat counterpart of the lateral cell group of the sexually dimorphic area (SDA) found in medial preoptic area (MPOA) gerbil of gerbils. The lateral SDA (lSDA) is critical for mating in male gerbils and contains most of the SDA cells projecting to the retrorubral field (RRF), a projection that is also important for mating. Therefore, to locate the counterpart of the lateral SDA, we traced the inputs to the rat RRF, which were dense in the ventral part of the bed nucleus of the stria terminalis (BST). To determine if the ventral BST or its projection to the RRF affects mating in male rats, we disrupted them bilaterally by placing cell-body lesions bilaterally in the ventral BST or unilaterally there and in the contralateral RRF. We also studied the effects of RRF lesions in both rats and gerbils. Bilateral ventral BST lesions, which left the medial preoptic nucleus intact, produced persistent and severe mating deficits. Disconnecting the ventral BST from the RRF also had long-lasting, but less severe, consequences. RRF lesions produced only temporary mating deficits in rats, but virtually eliminated mating in gerbils. The recovery of mating in rats after RRF, but not ventral BST, lesions, and the intermediate effects of disconnecting these areas from each other suggest that the ventral BST may contain mating-related projection neurons other than those projecting to the RRF or that its RRF-projecting cells send collaterals to another site. In either case, the pedunculopontine tegmental nucleus or raphe nuclei may be involved.

Animals↗
PubMed2000

The experimental investigation of ultrasonic properties for a sonicated contrast agent and its application in biomedicine.

The ultrasonic properties of a promising ultrasound (US) contrast agent, named SDA (sonicated dextrose albumin) are reported in this paper. SDA is a suspension of stable microencapsulated gas bubbles with average diameter 2.0 microm prepared from sonicated dextrose albumin. The ultrasonic linear and nonlinear parameters, such as acoustic velocity, sound attenuation and acoustic nonlinearity parameter B/A of SDA, as a function of its bubble concentration from 1.0 x 10(7) to 2.05 x 10(8) microbubbles/mL in the frequency range of 2-6 MHz are measured in vitro. The sound attenuation coefficients over 2-6 MHz are linearly proportional to the bubble concentration and frequency. It is important to point out that the acoustic nonlinearity parameter B/A for SDA has a very large value that nonlinearly increases with the increase of bubble concentration.

Albumins↗
PubMed2001

The angiotensin converting enzyme I/D polymorphism in Russian athletes.

The deletion (D) allele of the human ACE gene is associated with higher ACE activity than the insertion (I) allele. There is controversy as to whether the ACE genotype may be associated with elite athletic status; recent studies have identified no significant associations amongst those drawn from mixed sporting disciplines. However, such lack of association may reflect the mixed nature of such cohorts, given that an excess frequency of the I allele has been reported amongst elite endurance athletes, and an excess of the D allele amongst those engaged in more power-orientated sports. We examined this hypothesis by determining ACE I/D allele frequency amongst 217 Russian athletes (swimmers, skiers, triathletes and track-and-field participants) prospectively stratified by performance ('outstanding' or 'average'), and the duration of their event (SDA (<1 min), MDA (1 to 20 min), and LDA (>20 min): short, middle and long distance athletes respectively). ACE genotype and allele frequencies were compared to 449 controls. ACE genotype frequency amongst the whole cohort, or the outstanding athletes alone, was no different to that amongst sedentary controls. However, there was an excess of the D allele (frequency 0.72, P=0.001) amongst the outstanding SDA group, and an excess of the I allele (frequency 0.63, P=0.032) amongst the outstanding MDA group. These findings were replicated in the outstanding swimmers, with track and field SDA similarly demonstrating an excess of the D allele (P=0.01). There was no association found between the outstanding LDA and ACE genotype (P=0.27). These data not only confirm an excess of the D allele in elite SDA, and I allele in elite MDA, but also offer an explanation as to why any such association may be hard to detect amongst a heterogeneous cohort of mixed athletic ability and discipline.

Adult↗
PubMed1999

The cerebellum and cognition: cerebellar lesions do not impair spatial working memory or visual associative learning in monkeys.

Anatomical studies in non-human primates have shown that the cerebellum has prominent connections with the dorsal, but not the ventral, visual pathways of the cerebral cortex. Recently, it has been shown that the dorsolateral prefrontal cortex (DPFC) and cerebellum are interconnected in monkeys. This has been cited in support of the view that the cerebellum may be involved in cognitive functions, e.g. working memory. Six monkeys (Macaca fascicularis) were therefore trained on a classic test of working memory, the spatial delayed alternation (SDA) task, and also on a visual concurrent discrimination (VCD) task. Excitotoxic lesions were made in the lateral cerebellar nuclei, bilaterally, in three of the animals. When retested after surgery the lesioned animals were as quick to relearn both tasks as the remaining unoperated animals. However, when the response times (RT) for each task were directly compared, on the SDA task the monkeys with cerebellar lesions were relatively slow to decide where to respond. We argue that on the SDA task animals can prepare their responses between trials whereas this is not possible on the VCD task, and that the cerebellar lesions may disrupt this response preparation. We subsequently made bilateral lesions in the DPFC of the control animals and retested them on the SDA task. These monkeys failed to relearn the task. The results show that, unlike the dorsal prefrontal cortex, the cerebellum is not essential for working memory or the executive processes that are necessary for correct performance, though it may contribute to the preparation of responses.

Animals↗
PubMed2000

Stimulus deprivation amblyopia in human congenital ptosis: a study of 100 patients.

AIM: To investigate the frequency of stimulus deprivation amblyopia (SDA) in comparison with other reasons for amblyopia in human congenital ptosis. METHODS: The frequency and causes of amblyopia were evaluated in the 200 eyes of 100 patients. Congenital ptosis was present in 128 eyes (72 unilateral, 28 bilateral). The age at investigation was one year and older, with an average of 11 years and 10 months. Amblyopia was defined as best corrected visual acuity less than 1.0 or a difference between the two eyes of at least 0.2. The following causes of amblyopia were identified: amblyopiogenic refractive errors: astigmatism > or = 1 dpt, anisometropia > or = 1 dpt (79% cycloplegia) and strabismus. In cases with no other reasons for amblyopia, SDA was assumed. Statistical analysis was performed using the chi-square and the sign tests. RESULTS: The overall incidence of amblyopia in ptotic eyes was 89/128 (70%). In 3.9% of the cases (5/128; 2 eyes with unilateral and 3 eyes with bilateral ptosis) we assumed SDA. A comparison of ptotic eyes with (unilateral: n = 35, bilateral: n = 34) and without covered optical axis revealed the following: in the case of unilateral ptosis, amblyopia was found more often in ptotic eyes with covered optical axis: 30 out of 35 vs. 24 out of 37 (p = 0.06); in the case of bilateral ptosis this difference was significant: 27 out of 34 vs. 8 out of 22 (p < 0.05). In the case of SDA, the optical axis was covered in only a single eye, in a patient with bilateral ptosis. There was no difference in the incidence of anisometropia: 19 out of 53 vs. 14 out of 47 (p = 0.52). Astigmatism was found more frequently in ptotic eyes with covered optical axis in unilateral ptosis: 23 out of 35 vs. 16 out of 37 (p = 0.06) but not in bilateral ptosis: 21 out of 34 vs. 13 out of 22 (p > 0.9). Strabismus was found significantly more frequently in ptotic eyes with covered optical axis: 13 out of 35 vs. 4 out of 37 (p < 0.05) in unilateral ptosis and 7 out of 34 vs. 1 out of 22 (p = 0.13) in bilateral ptosis. CONCLUSION: In contrast to the classical animal models of stimulus deprivation amblyopia, this entity is rare in human congenital ptosis, perhaps because of the counter effect of compensating head posture. Disruption of fusion resulting in strabismus might be an additional indirect cause of amblyopia in congenital ptosis. Prophylactic amblyopia treatment in ptosis cases is important as long as no testing of visual acuity is possible in a child.

Adolescent↗
PubMedDate not supplied

Specific dynamic action in the shore crab, Carcinus maenas (L.), in relation to acclimation temperature and to the onset of the emersion response.

The rate of oxygen uptake (MO(2)) of shore crabs following a period of fasting varied directly with acclimation temperature, with a Q(10) of 2.96 between 7 degrees and 15 degrees C and a Q(10) of 2.11 between 15 degrees and 22 degrees C. The factorial rise in MO(2) following a meal (specific dynamic action [SDA]) ranged between 1.9 and 3.1 and varied with temperature, being highest at 15 degrees C and significantly lower at both 7 degrees and 22 degrees C, despite similar ration sizes in all groups. At 7 degrees C, the SDA coefficient and magnitude were significantly lower than at 15 degrees C, possibly due in part to the inhibition of protein synthesis. Both the time to peak and the duration of the SDA response were inversely related to temperature. SDA coefficients were inversely related to the amount of food consumed. The critical oxygen tension of inspired water (P(I)O(2)), which evoked the emersion response in fasted animals, increased with temperature and further increased at each temperature when the animals were fed. Thus, the threshold P(I)O(2) evoking the emersion response is directly related to relative metabolic oxygen demand in Carcinus.

Acclimatization↗
PubMedDate not supplied

Temperature and meal size effects on the postprandial metabolism and energetics in a boid snake.

We investigated the combined effect of meal size and temperature on the aerobic metabolism and energetics of digestion in Boa constrictor amarali. Oxygen uptake rates (Vd2;o2) and the duration of the digestion were determined in snakes fed with meals equaling to 5%, 10%, 20%, and 40% of the snake's body mass at 25 degrees and 30 degrees C. The maximum Vd2;o2 values attained during digestion were greater at 30 degrees C than at 25 degrees C. Both maximal Vd2;o2 values and the duration of the specific dynamic action (SDA) were attained sooner at 30 degrees C than at 25 degrees C. Therefore, the temperature effect on digestion in Boa is characterized by the shortening of the SDA duration at the expense of increased Vd2;o2. Energy allocated to SDA was not affected by meal size but was greater at 25 degrees C compared to 30 degrees C. This indicates that a postprandial thermophilic response can be advantageous not only by decreasing the duration of digestion but also by improving digestive efficiency. Maximal Vd2;o2 and SDA duration increased with meal size at both temperatures.

Adaptation, Physiological↗
PubMed1978

The influence of a wide range of absorbed cholesterol on plasma cholesterol levels in man.

The influence of absorbed dietary cholesterol on plasma cholesterol concentration was studied in two populations, one Seventh Day Adventist (SDA) vegetarian and one nonvegetarian, representing a broad range of plasma cholesterol values and dietary cholesterol intakes. As a group, the SDA vegetarians had significantly lower levels of plasma cholesterol and triglycerides than did the nonvegetarians. This hypolipidemic pattern in the SDA vegetarians was apparently closely related to dietary habits, sinceanother group of SDA who were nonvegetarian had significantly higher plasma cholesterol and triglyceride levels than their vegetarian counterparts. Both the dietary intake of cholesterol and the percentage absorption of cholesterol were lower in vegetarians than in nonvegetarians. The mass of cholesterol absorbed increased linearly with the mass of cholesterol ingested in all groups, but no relationship could be demonstrated between absorbed cholesterol and plasma cholesterol concentration.

Absorption↗
PubMed2003

Modification of plant lipids for human health: development of functional land-based omega-3 fatty acids.

We have remodeled canola seeds to accumulate the omega-3 fatty acid, stearidonic acid (SDA). In doing so, we have demonstrated the feasibility of developing a land-based source of functional omega-3 fatty acids on a large scale. Land-based omega-3 fatty acids represent a sustainable source of omega-3 fatty acids that can be produced on large acreages and delivered to consumers in a wide variety of functional foods. And unlike alpha-linolenic acid, SDA can provide eicosapentaenoic acid equivalence at moderate intakes. Widely applied, SDA-enriched foods could become a valuable tool for delivering recommended levels of omega-3 fatty acids to large portions of the population. By obviating the need for dietary changes, SDA-enriched foods may facilitate increased compliance with recommendations for daily omega-3 intakes.

Biotechnology↗
PubMed1996

DNA detection by strand displacement amplification and fluorescence polarization with signal enhancement using a DNA binding protein.

Strand displacement amplification (9SDA) is an isothermal in vitro method of amplifying a DNA sequence prior to its detection. We have combined SDA with fluorescence polarization detection. A 5'-fluorescein-labelled oligodeoxynucleotide detector probe hybridizes to the amplification product that rises in concentration during SDA and the single- to double strand conversion is monitored through an increase in fluorescence polarization. Detection sensitivity can be enhanced by using a detector probe containing an EcoRI recognition sequence at its 5'-end that is not homologous to the target sequence. During SDA the probe is converted to a fully double-stranded form that specifically binds a genetically modified form of the endonuclease EcoRI which lacks cleavage activity but retains binding specificity. We have applied this SDA detection system to a target sequence specific for Mycobacterium tuberculosis.

Base Sequence↗
PubMed1999

Temporal span of human echoic memory and mismatch negativity: revisited.

The stimulus onset asynchrony (SOA)-related decrease in mismatch negativity (MMN) amplitude has been used to infer a putative auditory sensory memory duration of 4-10 s. However, both increased standard-to-standard (SSA) and standard-to-deviant (SDA) gaps could contribute to the effect. Fourteen subjects were presented with standard and deviant tones with short (0.35 s) and long (3.5 s) SOAs. In addition, the SSA and SDA were separately manipulated to test the relative contributions of slower rate of standard tone presentation and longer SDA gap to the SOA-related decrease in MMN amplitude. The MMN amplitude decreased with long SOA by 61%. Increases in SSA and SDA resulted in intermediate 47% and 31% decreases, these manipulations explaining 67% of the long SOA effect (p<0.001). Consequently, echoic memory length cannot be directly inferred from an MMN-SOA dependency function.

Acoustic Stimulation↗
PubMed1997

Heritability of pre-adult viability differences can explain apparent heritability of sperm displacement ability in Drosophila melanogaster.

Sperm displacement has been the subject of a large number of evolutionary studies because of its effects on relative male reproductive success. To understand better the evolutionary role of variation in sperm displacement ability (SDA), an obvious aim is to measure its heritability. In this paper, we show that a standard method used to measure the heritability of SDA can be misleading. First, we show that using conventional methods (based on counts of adult offspring of multiply mated females), SDA appears to be heritable. However, an examination of potentially confounding variables strongly suggests that this result is misleading, and that the heritable component is more likely to be pre-adult viability. Consequently, it is likely that there is little measurable heritable genetic variation for SDA in D. melanogaster. We conclude that, although conventional methods of measuring sperm displacement will usually be adequate for phenotypic measurements, greater care must be taken when measuring genetic variances.

Animals↗
PubMed2004

Pythons metabolize prey to fuel the response to feeding.

We investigated the energy source fuelling the post-feeding metabolic upregulation (specific dynamic action, SDA) in pythons (Python regius). Our goal was to distinguish between two alternatives: (i) snakes fuel SDA by metabolizing energy depots from their tissues; or (ii) snakes fuel SDA by metabolizing their prey. To characterize the postprandial response of pythons we used transcutaneous ultrasonography to measure organ-size changes and respirometry to record oxygen consumption. To discriminate unequivocally between the two hypotheses, we enriched mice (= prey) with the stable isotope of carbon (13C). For two weeks after feeding we quantified the CO2 exhaled by pythons and determined its isotopic 13C/12C signature. Ultrasonography and respirometry showed typical postprandial responses in pythons. After feeding, the isotope ratio of the exhaled breath changed rapidly to values that characterized enriched mouse tissue, followed by a very slow change towards less enriched values over a period of two weeks after feeding. We conclude that pythons metabolize their prey to fuel SDA. The slowly declining delta13C values indicate that less enriched tissues (bone, cartilage and collagen) from the mouse become available after several days of digestion.

Analysis of Variance↗
PubMed1998

Ground red hot pepper agar in the isolation of yeasts of Candida spp.

The purpose of this study was to investigate and determine the value of a novel, simple and inexpensive selective medium for isolation of yeasts of Candida spp. - ground red hot pepper agar (GRHP). The study compared GRHP and Sabouraud dextrose agar (SDA), an insufficiently selective medium routinely used for primary isolation of yeasts. The comparison was based on qualitative and quantitative characterisation of growth of 25 bacterial strains, measurement of growth of 22 yeast strains and testing on clinical specimens. Qualitative tests on bacteria showed either significantly less growth on GRHP than on SDA, or no growth on GRHP. Quantitative tests confirmed these results; the number of colonies of all tested bacterial species and strains on GRHP was significantly lower than on SDA. With regard to the isolation of Candida spp., GRHP had the same properties as SDA. Statistical analysis showed no significant differences in the growth of Candida spp. and strains on the two media. All these results were confirmed by tests on clinical material. The results clearly show that GRHP agar is an economical medium for the isolation of yeasts of Candida spp., with excellent selectivity.

Bacteria↗
PubMed1987

Migration of teeth in shortened dental arches.

In shortened dental arches (SDA) the remaining premolars tend to migrate distally. This may lead to a decrease of the vertical dimension, resulting in an increased load on the anterior teeth. Consequently the number and intensity of the occlusal contacts between the front teeth increase. This may result in interdental spacing in the upper front region. In this study the pattern of migration of the teeth in subjects with SDA (n = 60) is described. The SDA group is compared with subjects having complete dental arches (n = 72). Although a systemic effect of SDA has been found on interdental spacing for subjects under 40 years of age, it is concluded that this migration is within acceptable levels.

Adult↗