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At least 163 records · Page 9Linked to original sources
PubMed2000

Relationship between specific dynamic action and protein deposition in calanoid copepods.

The link between specific dynamic action (SDA) and protein deposition was investigated in copepodites stage V of two calanoid copepod species, the neritic Acartia tonsa and the oceanic Calanus finmarchicus. This was done by measuring respiration before, during, and after a specific feeding period and measuring the incorporation of carbon into proteins. These were also measured on individuals incubated with cycloheximide, an antibiotic that inhibits protein synthesis. The cycloheximide treatment significantly diminished the magnitude of SDA in both A. tonsa and C. finmarchicus, and inhibited carbon incorporation into protein in both species. This provides evidence that the rate at which protein deposition takes place greatly affects the magnitude of SDA. The specific respiration rates of both starving and feeding copepods were generally higher in A. tonsa than in C. finmarchicus. This influenced SDA, the magnitude of SDA normalised to an 8 h feeding period being threefold higher in A. tonsa (78.7+/-25.7 nlO(2) µgC(-1)) than in C. finmarchicus (27.5+/-11.6 nlO(2) µgC(-1)). This difference may arise due to differences in energy allocation in the organisms of the copepodite V stage of the two species. In this stage C. finmarchicus deposits large quantities of storage lipids, predominately wax esters, whereas A. tonsa deposits proteins during somatic growth.

Journal Article↗
PubMed2001

Replication initiation proteins regulate a developmental checkpoint in Bacillus subtilis.

We identified a signaling pathway that prevents initiation of sporulation in Bacillus subtilis when replication initiation is impaired. We isolated mutations that allow a replication initiation mutant (dnaA) to sporulate. These mutations affect a small open reading frame, sda, that was overexpressed in replication initiation mutants and appears to be directly regulated by DnaA. Mutations in replication initiation genes inhibit the onset of sporulation by preventing activation of a transcription factor required for sporulation, Spo0A. Deletion of sda restored activation of Spo0A in replication initiation mutants. Overexpression of sda in otherwise wild-type cells inhibited activation of Spo0A and sporulation. Purified Sda inhibited a histidine kinase needed for activation of Spo0A. Our results indicate that control of sda by DnaA establishes a checkpoint that inhibits activation of Spo0A and prevents futile attempts to initiate sporulation.

Amino Acid Sequence↗
PubMed1976

[Cad antigen in the French population].

An investigation of Cad phenotypes in the French population had been carried out in 1973, in four Blood Transfusion Centers (Mulhouse, Nancy, Paris, Versailles), B and O red cells were tested with the Dolichos Biflorus lectin. Out of 78.528 donors, 56 were found to have the Cad antigen on their red cells. The mean frequency was 0,07%. Nevertheless, this frequency varied among the four above mentioned Blood Transfusion Centers: the observed differences were probably due to the preparation procedure of the Dolichos biflorus extract. The family investigation permitted the analysis of four families with at least three Cad individuals. The independence of the Cad system and of Auberger, Gc, Hp, C'3, PGM, Pac and ADA was demonstrated. A quantitative agglutination study on these Cad samples using the Dolichos biflorus lectin,and a selected AB serum showed a high variability of the erythrocyte Cad Strength, even within one family. Most Cad samples were found polyagglutinable when a sensitive technique and selected AB sera were used. All adult sera contained an anti-Cad1 antibody, except Cad1 individuals. Although strong Sda reactivity was always found in Cad red cells, the anti-Cad and anti Sda specificities were not identical: this was demonstrated by the absorption and inhibition tests of anti-Cad and anti-Sda reagents absorption and inhibition tests of anti-Cad and anti-Sda reagents with Sda material. From thf Cad red cells, there was no evidence of the existence of separable anti-A1 and anti-Cad agglutinins in the Dolichos biflorus lectin.

Blood Group Antigens↗
PubMed2005

Zeolite synthesis using degradable structure-directing agents and pore-filling agents.

Zeolites and molecular sieves are synthesized using organic structure-directing agents (SDAs) that have the potential to be degraded into fragments within the pore space so that they can be readily extracted at mild conditions. The zeolites and molecular sieves, VPI-8, ZSM-12, and ZSM-5, are synthesized using the ketal-containing SDA, 8,8-dimethyl-1,4-dioxa-8-azoniaspiro[4,5]decane (SDA-1). As expected, solids with unidimensional pore systems (VPI-8, ZSM-12) are much more difficult to process by this methodology than solids containing multidimensional pore systems (ZSM-5). Pore-filling agents (PFAs) such as isobutylamine and cyclopentylamine are used together with the ketal-containing SDA-1 to prepare ZSM-5. Extraction of the PFA is shown to be feasible, and its removal provides space for components to enter the zeolite micropores where they react with and cleave SDA-1. Removal of the cleavage fragments from SDA-1 gives ZSM-5 that has the appropriate pore volume, framework aluminum (measured by 27Al NMR), and catalytic behavior. Reasons for desiring this new type of zeolite synthesis method are enumerated.

Journal Article↗
PubMed1998

The compound 14-keto-stypodiol diacetate from the algae Stypopodium flabelliforme inhibits microtubules and cell proliferation in DU-145 human prostatic cells.

We investigated the effects of the drug 14-keto-stypodiol diacetate (SDA) extracted from the seaweed product Stypopodium flabelliforme, in inhibiting the cell growth and tumor invasive behavior of DU-145 human prostate cells. In addition, the molecular action of the drug on microtubule assembly was analyzed. The effects of this diterpenoid drug in cell proliferation of DU-145 tumor cells in culture revealed that SDA at concentrations of 5 microM decreased cell growth by 14%, while at 45 microM a 61% decrease was found, as compared with control cells incubated with the solvent but in the absence of the drug. To study their effects on the cell cycle, DU-145 cells were incubated with increasing concentrations of SDA and the distribution of cell-cycle stages was analyzed by flow cytometry. Interestingly, the data showed that 14-keto-stypodiol diacetate dramatically increased the proportion of cells in the G2/M phases, and decreased the number of cells at the S phase of mitosis, as compared with appropriate controls. Studies on their action on the in vitro assembly of microtubules using purified brain tubulin, showed that SDA delayed the lag period associated to nucleation events during assembly, and decreased significantly the extent of polymerization. The studies suggest that this novel derivative from a marine natural product induces mitotic arrest of tumor cells, an effect that could be associated to alterations in the normal microtubule assembly process. On the other hand, a salient feature of this compound is that it affected protease secretion and the in vitro invasive capacity, both properties of cells from metastases. The secretion of plasminogen activator (u-PA) and the capacity of DU-145 cells to migrate through a Matrigel-coated membrane were significantly inhibited in the presence of micromolar concentrations of SDA. These results provide new keys to analyze the functional relationships between protease secretion, invasive behavior of tumor cells and the microtubule network.

Cell Division↗
PubMed1994

Telencephalic connections of the sexually dimorphic area of the gerbil hypothalamus that influence male sexual behavior.

The sexually dimorphic area (SDA) of the gerbil hypothalamus is essential for mating in male gerbils. To determine if it affects mating through its connections with the ventral part of the lateral septal nucleus (LSv), the caudal part of the medial bed nucleus of the stria terminalis (caudal BSTm), or the medial amygdala-amygdalohippocampal area (MA-AHi), these connections were severed. Unilateral cell-body lesions were made in the SDA and in the contralateral LSv, caudal BSTm, or MA-AHi. Controls received the same lesions ipsilaterally. Other gerbils received lesions in the caudal BSTm and contra- or ipsilateral MA-AHi. Only contralateral lesions of the SDA and caudal BSTm severely impaired mating. Because contralateral lesions of the SDA and MA-AHi, or BSTm and MA-AHi, did not mimic this effect, the BSTm neurons that are needed for male sexual behavior through their connections with the SDA do not simply relay information to or from the MA-AHi.

Animals↗
PubMed1984

Diet, nutrition intake, and metabolism in populations at high and low risk for colon cancer. Relationship of diet to serum lipids.

Serum cholesterol, high-density lipoprotein cholesterol, and triglycerides of three groups of Seventh-day Adventists (SDAs)--true vegetarians, lacto-ovo vegetarians, and nonvegetarians--and the general population were measured and related to age, sex, and diet. True vegetarian SDAs had the lowest cholesterol levels while cholesterol levels of the other three groups were similar. Triglyceride levels were highest in the true vegetarian SDAs and lowest in general population. Cholesterol levels rose with increasing age while percentage of high-density lipoprotein cholesterol fell. Female SDAs in all three dietary groups had higher cholesterol levels than males. In all four groups percentage of high-density lipoprotein cholesterol was higher in females than in males. In the male subjects, cholesterol levels varied linearly and inversely with carbohydrate intake. Protein and fat intake in true vegetarian SDAs and lacto-ovo vegetarian SDA groups were lower than in the nonvegetarian SDA and general population groups. The differences in protein and fat intake were reflected in elevations in serum cholesterol levels. In the female subjects, cholesterol levels were also inversely correlated with carbohydrate intake but not as distinctly as in the males. True vegetarian SDA females ingested less protein and fat than the other three groups and exhibited lower serum cholesterol levels. Cholesterol levels in lacto-ovo vegetarian SDA, nonvegetarian SDA, and general population female subjects were similar and did not reflect differences in protein or fat intake. The true vegetarian dietary lifestyle resulted in lowest cholesterol levels, however, if it was breeched to the least extent, cholesterol levels rose. Thus, intake of skim, low fat, or whole milk resulted in similar serum cholesterol levels as did low or high egg consumption.

Adult↗
PubMed1984

Diet, nutrition intake, and metabolism in populations at high and low risk for colon cancer. Comparison of serum hexosaminidase levels.

Elevated levels of serum hexosaminidase (beta-2-acetamido-2-deoxy-D-glucoside; N-acetamidodeoxy-D-glucohydrolase, EC 3.2.1.30)(HEX) have been found in patients with cancer. In view of the reported low levels of colon cancer among Seventh-day Adventists (SDA) we determined levels of total HEX, and its heat-labile (HEX-A) and heat-stable (HEX-B) isozymes in vegetarian SDA, lacto-ovo vegetarian SDA, nonvegetarian SDA, and the general public. Lowest levels of total HEX and highest percentage of HEX-B were found in vegetarian SDA. The levels in the other three groups were comparable, and these differences were seen at all age levels. Female subjects exhibited significantly lower total HEX levels than the males but the percentage of HEX-B was the same.

Adult↗
PubMed2000

Highly unsaturated (n-3) fatty acids, but not alpha-linolenic, conjugated linoleic or gamma-linolenic acids, reduce tumorigenesis in Apc(Min/+) mice.

We showed previously that dietary eicosapentaenoic acid [EPA, 20:5(n-3)] is antitumorigenic in the APC:(Min/+) mouse, a genetic model of intestinal tumorigenesis. Only a few studies have evaluated the effects of dietary fatty acids, including EPA and docosahexaenoic acid [DHA, 22:6(n-3)], in this animal model and none have evaluated the previously touted antitumorigenicity of alpha-linolenic acid [ALA, 18:3(n-3)], conjugated linoleic acid [CLA, 77% 18:2(n-7)], or gamma-linolenic acid [GLA, 18:3(n-6)]. Stearidonic acid [SDA, 18:4(n-3)], the Delta6-desaturase product of ALA, which is readily metabolized to EPA, has not been evaluated previously for antitumorigenic efficacy. This study was undertaken to evaluate the antitumorigenicity of these dietary fatty acids (ALA, SDA, EPA, DHA, CLA and GLA) compared with oleic acid [OA, 18:1(n-9)] at a level of 3 g/100 g in the diets of APC:(Min/+) mice and to determine whether any alterations in tumorigenesis correspond to alterations in prostaglandin biosynthesis. Tumor multiplicity was significantly lower by approximately 50% in mice fed SDA or EPA compared with controls, whereas less pronounced effects were observed in mice fed DHA (P: = 0.15). ALA, CLA and GLA were ineffective at the dose tested. Although lower tumor numbers coincided with significantly lower prostaglandin levels in SDA- and EPA-fed mice, ALA and DHA supplementation resulted in equally low prostaglandin levels, despite proving less efficacious with regard to tumor number. Prostaglandin levels did not differ significantly in the CLA and GLA groups compared with controls. These results suggest that SDA and EPA attenuate tumorigenesis in this model and that this effect may be related in part to alterations in prostaglandin biosynthesis.

6-Ketoprostaglandin F1 alpha↗
PubMed1992

Strand displacement amplification--an isothermal, in vitro DNA amplification technique.

Strand Displacement Amplification (SDA) is an isothermal, in vitro nucleic acid amplification technique based upon the ability of HincII to nick the unmodified strand of a hemiphosphorothioate form of its recognition site, and the ability of exonuclease deficient klenow (exo- klenow) to extend the 3'-end at the nick and displace the downstream DNA strand. Exponential amplification results from coupling sense and antisense reactions in which strands displaced from a sense reaction serve as target for an antisense reaction and vice versa. In the original design (G. T. Walker, M. C. Little, J. G. Nadeau and D. D. Shank (1992) Proc. Natl. Acad. Sci 89, 392-396), the target DNA sample is first cleaved with a restriction enzyme(s) in order to generate a double-stranded target fragment with defined 5'- and 3'-ends that can then undergo SDA. Although effective, target generation by restriction enzyme cleavage presents a number of practical limitations. We report a new target generation scheme that eliminates the requirement for restriction enzyme cleavage of the target sample prior to amplification. The method exploits the strand displacement activity of exo- klenow to generate target DNA copies with defined 5'- and 3'-ends. The new target generation process occurs at a single temperature (after initial heat denaturation of the double-stranded DNA). The target copies generated by this process are then amplified directly by SDA. The new protocol improves overall amplification efficiency. Amplification efficiency is also enhanced by improved reaction conditions that reduce nonspecific binding of SDA primers. Greater than 10(7)-fold amplification of a genomic sequence from Mycobacterium tuberculosis is achieved in 2 hours at 37 degrees C even in the presence of as much as 10 micrograms of human DNA per 50 microL reaction. The new target generation scheme can also be applied to techniques separate from SDA as a means of conveniently producing double-stranded fragments with 5'- and 3'-sequences modified as desired.

Base Sequence↗
PubMed2005

Impact of antimicrobial ingredients and irradiation on the survival of Listeria monocytogenes and the quality of ready-to-eat turkey ham.

Irradiation is an effective technology in eliminating Listeria monocytogenes, but it induces quality changes in meat products at or above specific radiation doses. To minimize irradiation-induced quality changes, only low irradiation doses are recommended. However, low-dose irradiation provides a chance for some pathogens to survive and proliferate during prolonged storage. To solve this problem, antimicrobial ingredients [2% sodium lactate (SL), 0.1% sodium diacetate (SDA), 0.1% potassium benzoate (PB)] and low-dose irradiation were combined and tested for their effects on the growth of L. monocytogenes and meat quality. The log10 reductions of L. monocytogenes in hams following exposure to 1.0 to 2.5 kGy of irradiation ranged from 2.0 to 5.0. The D10 values were 0.52 kGy for control ham or ham with PB, SL, or PB + SL; 0.49 kGy for ham with SL+SDA; and 0.48 kGy for ham with PB + SL + SDA (PSS). Addition of SL + SDA or PB + SL in combination with 1.0 kGy of irradiation was effective in suppressing the growth of L. monocytogenes for about 6 wk when stored at 4 degrees C, whereas 2.0 kGy of irradiation was listeriostatic. Ham irradiated with 1 kGy in combination with PSS was listeriostatic throughout storage. SL increased firmness of turkey hams, and sensory panelists noted that the saltiness was a little higher in products containing SL, but its overall impact on quality was minimal. Amounts of benzene were detected in irradiated hams with PB, showing PB was not fit as an antimicrobial ingredient for irradiated foods. In conclusion, 2% SL and 0.1% SDA in combination with low-dose irradiation were effective in ensuring the safety of ready-to-eat meat products against L. monocytogenes.

Animals↗
PubMed2003

Maximizing research opportunities: secondary data analysis.

Knowledge development in nursing can be enhanced by broadening the understanding of legitimate scientific inquiry. SDA uses existing data to answer research questions and can be especially useful for nurse researchers. Advantages of SDA include its potential for resource savings and its cost-effectiveness. Also, the investigator can circumvent data collection challenges such as finding appropriate participants. However, SDA does not require less rigor. A sound conceptualization of the research problem is still required, and identifying and obtaining appropriate data for SDA can be quite time-consuming. Nevertheless, SDA can be both a practical and appropriate research process that enables nurses to maximize their opportunities for answering important clinical questions.

Bias↗
PubMed1996

Selective discrete Fourier transform algorithm for time-frequency analysis: method and application on simulated and cardiovascular signals.

The Selective Discrete Fourier transform (DFT) Algorithm [SDA] method for the calculation and display of time-frequency distribution has been developed and validated. For each time and frequency, the algorithm selects the shortest required trace length and calculates the corresponding spectral component by means of DFT. This approach can be extended to any cardiovascular related signal and provides time-dependent power spectra which are intuitively easy to consider, due to their close relation to the classical spectral analysis approach. The optimal parameters of the SDA for cardiovascular-like signals were chosen. The SDA perform standard spectral analysis on stationary simulated signals as well as reliably detect abrupt changes in the frequency content of nonstationary signals. The SDA applied during a stimulated respiration experiment, accurately detected the changes in the frequency location and amplitude of the respiratory peak in the heart rate (HR) spectrum. It also detected and quantified the expected increase in vagal tone during vagal stimuli. Furthermore, the HR time-dependent power spectrum displayed the increase in sympathetic activity and the vagal withdrawal on standing. Such transient changes in HR control would have been smeared out by standard heart rate variability (HRV), which requires consideration of long trace lengths. The SDA provides a reliable tool for the evaluation and quantification of the control exerted by the Central Nervous System, during clinical and experimental procedures resulting in nonstationary signals.

Adult↗
PubMed1994

A 6-year follow-up study of oral function in shortened dental arches. Part II: Craniomandibular dysfunction and oral comfort.

In this clinical 6-year follow-up study subjects with shortened dental arches (SDA, n = 55), characterized by the absence of molar support, are compared with subjects with complete dental arches (CDA, n = 52) with respect to items concerning craniomandibular dysfunction and oral comfort. In addition, a small group of subjects with SDA and removable partial dentures in the lower jaw (SDA + RPD, n = 19) is included in this study. Oral comfort is defined using the following criteria: (i) absence of pain and distress, meaning the absence of signs and symptoms of craniomandibular dysfunction: (ii) chewing ability; and (iii) appreciation of the appearance of the dentition in relation to absent posterior teeth. Additionally, complaints about the free-end RPD are described. It is concluded that: (i) a SDA (consisting of 3-5 occlusal units, OU) is not a risk factor for CMD and is able to provide long-term sufficient oral comfort; and (ii) free-end RPD (in the lower jaw) in SDA do not prevent CMD and do not improve oral function in terms of oral comfort.

Adult↗
PubMed2004

Analysis of the absorbance spectra of skin lesions as a helpful tool for detection of major pathophysiological changes.

BACKGROUND/AIMS: Although reflectance spectrophotometry is often applied to measurement of skin color, raw data of reflectance spectra of normal and lesional skin are difficult to analyze. The purpose of this pilot study was to determine whether measurement of spectral difference in absorbance (SDA) between various skin lesions and normal skin adjacent to them could yield useful information for clinics in dermatology. METHODS: We studied spectral reflectance of a total of 173 various skin lesions. After converting obtained reflectance into apparent absorbance A (=log(10)(1/reflectance)), we examined the profile of SDA, that is, A(lesion)-A(normal skin) in the range of 400-700 nm, and compared them with the absorbance spectra of melanin and hemoglobin. RESULTS: SDA of epidermal pigmentary disorders was similar to the absorption spectrum of melanin in vitro, but the cases with intradermal melanin deposition showed a different pattern, reflecting the scattering effect of the dermis. SDA of erythematous lesions was similar to the spectra of either oxygenated or reduced hemoglobin, and varied according to the oxygenated level of cutaneous blood. SDA of lesions with a combination of factors appeared as a simple summation of spectra corresponding to each of the factors. CONCLUSIONS: Our method may offer easy and quick detection of major pathophysiological changes in skin lesions.

Hemoglobins↗
PubMed1999

Variation in Microbial Identification System accuracy for yeast identification depending on commercial source of Sabouraud dextrose agar.

The accuracy of the Microbial Identification System (MIS; MIDI, Inc. ) for identification of yeasts to the species level was compared by using 438 isolates grown on prepoured BBL Sabouraud dextrose agar (SDA) and prepoured Remel SDA. Correct identification was observed for 326 (74%) of the yeasts cultured on BBL SDA versus only 214 (49%) of yeasts grown on Remel SDA (P < 0.001). The commercial source of the SDA used in the MIS procedure significantly influences the system's accuracy.

Agar↗
PubMed1973

Measles virus ribonucleic acid and protein synthesis: effects of 6-azauridine and cycloheximide on viral replication.

Cycloheximide and 6-azauridine were employed to study the time course of measles virus protein and nucleic acid syntheses in AV3 cells. Synthesis of ribonucleic acid (RNA) essential for infectivity was first detected at 6 hr and increased concurrently with the formation of essential protein. Maximum levels of virus-specific RNA and protein were present by 18 hr, a time when only 5% of progeny virus was detected. Essential RNA and protein syntheses preceded the formation of infectious virus by at least 10 to 12 hr. The time course of RNA and protein syntheses essential for the formation of complement-fixing (CF) antigen and salt-dependent agglutinin (SDA) was also determined. RNA synthesis essential for the formation of SDA was first detected at 2 hr and was present maximally by 6 hr, whereas SDA-protein increased concurrently with the protein essential for infectivity. This suggested that the last protein essential for infectivity may be SDA. RNA synthesis essential for the formation of CF antigen was first detected at 4 hr, while CF-protein increased at 5 hr and preceded SDA-protein and protein essential for infectivity by approximately 3 hr. Reversal of inhibition of protein synthesis by cycloheximide indicated that early protein synthesis (1 to 3 hr) was required for the formation of infectious virus. The data suggest that the relatively long eclipse period observed with measles virus is related to a long maturation period rather than to late formation of early proteins, viral RNA, or structural proteins.

Amnion↗
PubMed1997

Subdiaphragmatic vagal deafferentation fails to block feeding-suppressive effects of LPS and IL-1 beta in rats.

To evaluate the role of subdiaphragmatic vagal afferent fibers in mediating the inhibition of food intake produced by peripheral administration of bacterial lipopolysaccharide (LPS) and the proinflammatory cytokine interleukin-1 beta (IL-1 beta), we assessed the ability of 100 micrograms/kg ip LPS and 2 micrograms/kg ip human recombinant IL-1 beta to suppress solid food intake during the first 3 and 6 h of the dark cycle in rats with selective vagal rootlet deafferentation (SDA, n = 15) and in sham surgical control rats (Con, n = 17). SDA was produced by a combination of dorsal subdiaphragmatic truncal vagotomy and left vagal afferent rootlet transection as the left vagus enters the caudal brain stem. Both LPS and IL-1 beta significantly suppressed food intake at 3 and 6 h in both Con and SDA rats, and SDA failed to attenuate the LPS- and IL-1 beta-induced reductions in food consumption relative to the suppression seen in controls. Peripheral administration of the gut-brain peptide cholecystokinin (CCK) suppressed 30-min 12.5% liquid glucose consumption in control, but not in SDA rats, consistent with previous demonstrations of the role of subdiaphragmatic vagal afferents in the mediation of CCK satiety. These data demonstrate that subdiaphragmatic vagal afferents are not necessary for the feeding-suppressive actions of peripherally administered LPS and IL-1 beta and suggest that peripheral LPS and IL-1 beta may inhibit food intake via humoral and/or splanchnic visceral afferent pathways.

Afferent Pathways↗