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PubMed1993

Ontogeny of the sexually dimorphic area of the gerbil hypothalamus.

The sexually dimorphic area (SDA) of the gerbil hypothalamus is a set of cell groups in the medial preoptic area that is essential for masculine sexual behavior and implicated in the hormonal control of scent making and ultrasound production. The adult SDA shrinks after gonadectomy unless the gerbils receive testosterone. So does the SDA pars compacta, a small cell group in the SDA of males that is seldom seen in females. Here, development of the SDA and SDApc, and of a second, small, compact cell group, the cmSDApc, that lies caudal and medial to the SDApc, is described. Development of the SDApc and cmSDApc was studied quantitatively by assessing their incidence and volume in both sexes from birth (PND 1) to adulthood (PND 150). The volume of the entire SDA was studied from PND 45 to 150. In male gerbils, puberty begins around PND 40 and is complete by PND 90-120. The male SDA enlarged relative to the cross-sectional area of the hypothalamus as puberty began, but the female SDA did not. The SDApc was present in virtually all gerbils at birth and was the same size in both sexes. Over the next two weeks, the SDApcs of females disappeared while those of males persisted and doubled in size. Like the SDApc, the cmSDApc was larger and more common in males than in females, but it became smaller and less prevalent in both sexes during the first two weeks after birth.

Animals↗

PubMed1984

Lesions of the sexually dimorphic area disrupt mating and marking in male gerbils.

At the border between the medial preoptic area (MPOA) and the anterior hypothalamus (AH), gerbils have a sexually dimorphic area (SDA) that accumulates and responds to gonadal steroids. To assess the role of the SDA in the hormonal control of two sexually dimorphic behaviors, masculine sexual behavior and ventral scent marking, we studied changes in these behaviors in male gerbils after lesioning the lateral SDA or the entire SDA. Lateral SDA lesions disrupt openfield scent marking, at least temporarily, and produce long-lasting deficits in, but do not abolish, mating behavior. Lesioning both the medial and the lateral SDA produces more profound deficits in mating and marking. Similar lesions anterior or posterior to the SDA also impair these behaviors, but their effects are less severe. Thus the SDA is more important than other parts of the MPOA-AH in the control of mating and marking in male gerbils.

Animals↗

PubMed2006

Specific dynamic action: a century of investigation.

Specific dynamic action (SDA) is the term used to refer to the increased metabolic expenditure that occurs in postprandial animals. Postprandial increases in metabolism were first documented in animals over two hundred years ago, and have since been observed in every species thus far examined. Ironically, the ubiquity of this physiological response to feeding understates its complex nature. This review is designed to summarize both classical and modern hypotheses regarding the causality of SDA as well as to review important findings from the past century of scientific research into SDA. A secondary aim of this work is to emphasize the importance of carefully designed experiments and systematic hypothesis testing to make more rapid progress in understanding the physiological processes that contribute to SDA. I also identify three areas in SDA research that deserve more detailed investigation. The first area is identification of the causality of SDA in 'model' organisms. The second area is characterization of SDA responses in novel species. The third area is exploration of the ecological and potential evolutionary significance of SDA in energy budgets of animals.

Animals↗

PubMed2026

An introductory practical guide to secondary data analysis in pediatric urology.

INTRODUCTION: Secondary data analysis (SDA) has become an increasingly important approach in pediatric urology, enabling the study of long-term outcomes, care variation, and disparities in populations with chronic or congenital urologic conditions. With the growing availability of large datasets, a structured approach to designing and conducting SDA studies is increasingly relevant. OBJECTIVES: To provide an introductory, practical guide to SDA in pediatric urology by (1) summarizing commonly used data sources with representative studies, (2) outlining a stepwise approach to designing and executing SDA studies, and (3) highlighting key methodological considerations, limitations, and opportunities for future work. STUDY DESIGN: Narrative review of existing literature and commonly used datasets relevant to pediatric urology, including administrative claims, hospital encounter databases, clinical registries, electronic health record networks, and population-based surveys. RESULTS: Data sources differ in scope, clinical granularity, longitudinal follow-up, and representativeness, and each is suited to specific research questions. We present a practical workflow for SDA, including dataset selection, cohort definition, and analytic planning. Linkage across datasets can provide a more comprehensive view of care patterns and outcomes, although feasibility is influenced by legal, technical, and data-quality constraints. DISCUSSION: SDA enables population-level analyses and the study of rare conditions that are challenging to evaluate through single-center or prospective designs. However, careful cohort definition, feasibility assessment, and awareness of data limitations are essential to ensure validity and interpretability. CONCLUSION: SDA provides a scalable, cost-efficient framework for generating meaningful evidence in pediatric urology. Continued efforts to harmonize data elements, improve linkage infrastructure, and support cross-institution collaboration will enhance the quality and impact of future research. This article provides a practical framework and examples to support the design and execution of SDA studies.

Humans↗

PubMed1980

Specific dynamic action and diet in largemouth bass, Micropterus salmoides (Lacépède).

Apparent specific dynamic action (SDA) in largemouth bass (5-28 g) was equated to oxygen uptake subsequent to the ingestion of a meal. The effects of six diets on apparent SDA were investigated, one balanced or standard diet and five consisting of different proportions of protein and carbohydrate. Apparent SDA was positively related to gross energy ingested and to the level of dietary protein. For a given energy intake, apparent SDA was highest and lowest for diets of 100% protein and 100% carbohydrate, respectively. Evidence of a protein-sparing effect was found when the carbohydrate component represented 25% of the diet and the energy intake was less than 0.8 kcal. Apparent SDA was divided into mechanical SDA, the energy cost for the physical processing of food, and biochemical SDA, the energy cost of anabolic and catabolic processes associated with a meal. Biochemical SDA increased with energy ingested irrespective of diet and was higher by approximately an order of magnitude when bass were fed 1.5 kcal of a 100% protein diet than when fish received an isocaloric meal of 100% carbohydrate. Rate of oxygen uptake following feeding remained above the prefeeding level for 12-72 hours depending on diet and energy ingested.

Animals↗

PubMed2000

In situ strand displacement amplification: an improved technique for the detection of low copy nucleic acids.

Strand displacement amplification (SDA) is an isothermal, enzymatic method for the exponential synthesis of target nucleic acids which traditionally requires two pairs of oligoprimers. One pair, described as "bumpers", serves to generate target specific single stranded DNA after heat denaturation of double stranded DNA subsequent to primer annealing and extension. We report here the in situ (IS) application of SDA (IS-SDA) using nicked DNA targets which eliminate the need for heat denaturation and bumpers. Productive nicking can be generated by restriction endonuclease activity, exposure to dry heat, paraffin embedding, or mild depurination. IS-SDA, followed by in situ hybridization (ISH) allows for the routine detection of single copy HIV-1 DNA as well as HPV DNA in both cell lines and tissue sections. Detection of hepatitis C RNA in liver biopsy specimens using reverse transcription IS-SDA (RT-IS-SDA) was performed with direct incorporation of the reporter nucleotide. The amplification of RNA targets does require bumper primers, although not an initial denaturation step. Extensive analyzes demonstrated that SDA-ISH is as sensitive as polymerase chain reaction (PCR)-ISH and that each are more sensitive than in situ hybridization coupled to catalyzed signal amplification (CSA). Moreover. SDA-ISH is technically much simpler than PCR-ISH because it is isothermal and does not require an initial denaturation.

DNA Primers↗

PubMed1993

Empirical aspects of strand displacement amplification.

The most attractive feature of SDA is its operation at a single temperature, which removes the need for instrumented temperature cycling as with PCR and the ligase chain reaction. Highly reproducible temperature profiles, over a large array of samples, can burden the accuracy and expense of an amplification technique. However, the expense of a temperature cycler is offset somewhat by the cost of additional enzymes used in isothermal techniques. In comparisons with isothermal, transcription-based techniques, SDA requires fewer enzymes and has a simpler mechanism. SDA may also be more robust than transcription-based processes because it is not susceptible to contaminating ribonuclease activity. This is generally more of a concern when using clinical samples. The most significant disadvantage of SDA is its inability to efficiently amplify long target sequences. Until this short-coming is eliminated, SDA will be assigned to the diagnostic laboratory along with the ligase chain reaction. Currently, SDA cannot compete with PCR in research applications such as the isolation of gene sequences. The second disadvantage of SDA is that it operates at relatively low (nonstringent) temperatures, which produces considerable background reactions. Consequently, SDA reaction products cannot be analyzed routinely by ethidium-stained gel electrophoresis, as is used commonly with PCR, unless the target sample contains a large number of initial targets.

Base Composition↗

PubMed2001

Detection of Chlamydia trachomatis and Neisseria gonorrhoeae by enzyme immunoassay, culture, and three nucleic acid amplification tests.

The purpose of this study was to evaluate and compare three commercially available nucleic acid amplification tests (NAATs) for the detection of Neisseria gonorrhoeae and Chlamydia trachomatis. Roche PCR and Becton Dickinson strand displacement amplification (SDA) were performed on 733 endocervical swab specimens from commercial sex workers. Abbott ligase chain reaction (LCR) was performed on a subset of 396 samples. Endocervical specimens from all women were also tested by culture for N. gonorrhoeae and by Syva MicroTrak enzyme immunoassay (EIA) for C. trachomatis. A positive N. gonorrhoeae result was defined as a positive result by culture or by two NAATs, and a positive C. trachomatis result was defined as a positive result by two tests. According to these definitions, the sensitivities and specificities for the subsample of 396 specimens of N. gonorrhoeae culture, PCR, SDA, and LCR were 69.8, 95.2, 88.9, and 88.9% and 100, 99.4, 100, and 99.1%, respectively; the sensitivities and specificities of C. trachomatis EIA, PCR, SDA, and LCR were 42.0, 98.0, 94.0, and 90.0% and 100, 98.0, 100, and 98.6%, respectively. The performance characteristics of N. gonorrhoeae culture, PCR, and SDA and C. trachomatis EIA, PCR, and SDA for all 733 specimens were defined without inclusion of LCR results and by discrepant analysis after resolution of discordant N. gonorrhoeae PCR results and of discordant C. trachomatis EIA and PCR results by LCR testing. The sensitivities of N. gonorrhoeae culture, PCR, and SDA before and after LCR resolution were 67.8, 95.7, and 93.9% and 65, 95.8, and 90.0%, respectively. The sensitivities of C. trachomatis EIA, PCR, and SDA decreased from 39.4, 100, and 100% to 38.7, 98.7, and 94.7%, respectively. All three NAATs proved to be superior to N. gonorrhoeae culture and to C. trachomatis EIA. The accuracies of the different NAATs were quite similar. SDA was the only amplification assay with 100% specificity for detection of both N. gonorrhoeae and C. trachomatis in endocervical specimens.

Cervix Uteri↗

PubMed1982

Clinical and etiological aspects of senile dementia.

Some clinical and etiological aspects of senile dementia of the Alzheimer type (SDA) were elucidated in a case control study of 63 SDA patients and 91 controls. The SDA patients had significantly more commonly both senile and presenile dementia in parents and sibs than the controls. The occurrence of senile dementia in parents or sibs increased the risk for SDA by about 900% when all other relevant factors were taken into account in multiple logistic risk function analysis. The increase of the risk for SDA associated with the occurrence of presenile dementia in sibs was even greater but not statistically significant because of other factors and sample size. There was a negative correlation between the occurrence of hypertension and angina pectoris and SDA, which may be partly due to selective diagnostic criteria of SDA. The beta-globulin fraction of cerebrospinal fluid was significantly reduced in the electrophoresis in the SDA patients compared with the controls.

Aged↗

PubMed2006

[Comparison of shortened dental arches with complete dental arches by clinical examinations].

PURPOSE: Recently, there have been reports in favor of avoiding prosthodontic intervention as Shortened Dental Arch (SDA) in Northern Europe. However, many of these reports were conducted through interviews and questionnaires, and so the evaluation of the results lacked objectivity. Thus, this research analyzed the clinical status of SDA. METHODS: For the selection of subjects, seven patients (average age: 59.3+/-13.2 years old) who had had the free-end missing on both sides of the lower dental arches for over five years were chosen as the SDA group. As the complete dental arch (CDA) group, seven patients (average age: 61.3+/-9.6 years old) who had no clinical defects in their masticatory function, and who had no missing teeth other than the third molar, were selected. Measurement items in this study were occlusal contact areas for the mandible premolar, center of force, occlusion time, and interdentium. The Mann-Whitney U test was used for statistical analysis and the significance level was assumed to be 5%. RESULTS: The results were as follows: 1) The occlusal contact area of the mandible premolar of SDA was significantly large. 2) The center of force of SDA was significantly forward. 3) The occlusion time of SDA had a tendency of prolongation. 4) Interdentium of 3 2 | 2 3, 4 3 | 3 4 and 5 4 | 4 5 of SDA were significantly wide. CONCLUSIONS: There were differences of clinical parameters between SDA and CDA in this study.

Aged↗

PubMed2001

Enhanced inhibition of Listeria monocytogenes and salmonella enteritidis in meat by combinations of sodium lactate and diacetate.

The antimicrobial activities of sodium lactate (SL) and sodium acetate (SA) are well documented, but there is limited information on the effect of their combination or of the combination of SL and sodium diacetate (SDA) on survival and growth of Listeria monocytogenes and salmonellae in meat. Effects of SL (1.8 and 2.5%), SDA (0.1 and 0.2%), or SA (0.2%) and their combinations on the behavior of L monocytogenes and Salmonella enterica serovar Enteritidis were investigated in sterile comminuted beef (pH 6.3, 79% moisture) during storage at 5 and 10 degrees C. Although L. monocytogenes grew faster than Salmonella Enteritidis in control samples at 10 degrees C, numbers of both pathogens increased from 3.5 to approximately 8.0 log CFU/g after 20 days. SL (1.8%) decreased the growth rate of both L. monocytogenes and Salmonella Enteritidis. SDA (0.2%) was more effective than SL in decreasing the growth rate of L monocytogenes, and it caused a more than 1 log CFU/g decline in initial numbers of Salmonella Enteritidis during storage for 25 days at 10 degrees C. Synergy was observed by combinations of SL and SDA. Combinations of 2.5% SL and 0.2% SDA were bacteriostatic to L. monocytogenes and bactericidal to Salmonella Enteritidis after 20 days at 10 degrees C. At 5 degrees C, a listeriostatic effect was produced by 1.8% SL + 0.1% SDA, whereas numbers of Salmonella Enteritidis were less than 10 cells/g after refrigeration for 30 days. Although SA was consistently and significantly less inhibitory than SDA, its mixtures with SL also demonstrated synergistic activity against both pathogens. Combinations of 2.5% SL and 0.2% SDA can be expected to greatly enhance the safety of refrigerated and temperature-abused ready-to-eat meats.

Animals↗

PubMed2003

Gamma irradiation of fine-emulsion sausage containing sodium diacetate.

Listeria monocytogenes, a psychrotrophic foodborne pathogen, is a frequent postprocess contaminant of ready-to-eat (RTE) meat products, including frankfurters and bologna. Ionizing radiation can eliminate L. monocytogenes from RTE meats. Sodium diacetate (SDA) incorporated into fine-emulsion sausages inhibits the growth of L. monocytogenes. Irradiation of L. monocytogenes suspended in SDA solutions resulted in synergistic reductions of the microorganism. L. monocytogenes populations were reduced by > 9 log10 units at a radiation dose of 1.5 kGy when suspended in 0.125% SDA solution. In contrast, the D10-values (the ionizing radiation doses required to reduce the population by 90%) were 0.58, 0.59, 0.57, and 0.53 kGy for L. monocytogenes populations suspended in emulsions containing 0, 0.125, 0.25, and 0.5% SDA, respectively. The D10-values for L. monocytogenes surface inoculated onto frankfurters dipped in 0, 0.125, 0.25, and 0.5% SDA solutions were 0.58, 0.53, 0.54, and 0.52 kGy, respectively. Postirradiation growth of L. monocytogenes suspended in beef bologna emulsion at 9 degrees C was dependent on SDA concentration and ionizing radiation dose. Very small, but statistically significant, changes in bologna redness, lipid oxidation, and shear force were observed for the beef bologna emulsion with the highest SDA concentration (0.5%) and irradiation dose (3.0 kGy). SDA can inhibit the proliferation of L. monocytogenes surviving the irradiation process with minimal impact on fine-emulsion sausage color, lipid oxidation, and firmness when used within regulatory limits.

Animals↗

PubMed1987

[Semi-quantitative evaluation of the intrapartum variable deceleration of the FHR pattern and its association with umbilical cord blood gas analysis].

Variable daceleration of FHR combined with no other abnormal pattern was semi-quantitatively evaluated to establish the diagnostic value of variable deceleration for fetal distress. FHR charts of 55 low risk vaginal deliveries by direct monitoring were analysed and the SDA (Sum of Dip Area) was calculated using the following equation: SDA = sigma Duration of dip (sec.) X Amplitude of dip (bpm.) X 10(-2) and correlation between SDA and umbilical cord blood gas analysis was obtained. A significant correlation was observed between SDA during labor (from 5 cm cervical dilation to delivery) and cord blood gas data. pHuv:r = -0.445 (p less than 0.005), PO2uv:r = -0.358 (p less than 0.01), BEuv:r = -0.538 (p less than 0.001), pHua:r = -0.441 (p less than 0.005), BEua:r = -0.463 (p less than 0.001). In 14 cases which showed prolonged deceleration (PD:more than 120 sec. in duration and below 100 bpm. in dip), excellent correlation was observed between the SDA of PD and pHuv:pHuv = 7.425-7.74 X 10(-4) SDA of PD (r = -0.756, p less than 0.005), whereas in 21 cases with severe variable deceleration (SVD:more than 60 sec. and recovered within 120 sec. in duration or below 60 bpm. in dip) no significant correlation was seen between the SDA of SVD and pHuv. These results suggest that the SDA value is helpful in evaluating variable deceleration during labor.

Female↗

PubMed1984

Sialodacryoadenitis in the rat: effects of immunosuppression on the course of the disease.

Eight-week-old outbred male and female Crl:CD(SD)BR rats were treated with prednisolone (PR) or cyclophosphamide (CY) and were inoculated intranasally with sialodacryoadenitis (SDA) virus. The course of the disease was compared with nonimmunosuppressed, SDA virus-inoculated rats of the same stock. Criteria used to compare SDA in the 3 groups, included histologic changes in salivary and lacrimal glands, immunofluorescent microscopy of paraffin-embedded tissues, serum amylase levels, and antibody response. Based on these criteria, there was little detectable difference in the course and intensity of SDA in PR-treated and nonimmunosuppressed rats. In CY-treated rats, there was a delay in the onset of SDA, in the appearance of inflammatory cells in affected glands, and in the reparative process in the salivary and lacrimal glands. Viral antigen persisted longer in CY-treated rats than in PR-treated and nonimmunosuppressed rats. Antibody to SDA virus was not detected in CY-treated rats. The efficacy of immunosuppression by PR and CY was confirmed by the sheep erythrocyte agglutination procedure performed in selected rats. Male and female rats of the same strain were immunosuppressed beginning 4 weeks after inoculation with SDA virus to produce recrudescence of the disease. Histologic examination of salivary and lacrimal glands, immunofluorescent microscopy, serum amylase values, and viral isolation studies did not reveal evidence of reactivation of a persistent viral infection or viral shedding. Based on these studies, there is no evidence that SDA virus may persist as an inapparent infection after recovery from the disease.

Amylases↗

PubMed1985

Autoradiographic localization of estrogen and androgen receptors in the sexually dimorphic area and other regions of the gerbil brain.

Autoradiography was used to localize sex hormone-accumulating cells in the gerbil brain. Some areas had a high density of both androgen and estrogen receptors. These areas included the lateral septum, the bed nucleus of the stria terminalis, the medial and cortical amygdaloid nuclei, the medial preoptic area (MPOA), the arcuate nucleus, the ventromedial hypothalamus, and the periventricular central gray. This distribution of hormone receptors agrees closely with that seen in other mammals. In contrast to what has been reported for other species, the distribution of estradiol-accumulating cells in the gerbil MPOA is different in males and females. Estradiol uptake in the posterior MPOA followed the morphology of a sexually dimorphic area (SDA) and was therefore sexually dimorphic. Moreover, the percentage of SDA cells that accumulated estradiol appeared to be higher in males than in females. The pattern of androgen accumulation also followed the morphology of the SDA but differed from the pattern of estrogen accumulation in one way. The uptake of 5 alpha-dihydrotestosterone in the SDA pars compacta (pc), a component of the SDA, was much greater than in the rest of the SDA. This was not true for estradiol. Since most females lack the SDApc, androgen uptake in the gerbil SDA may also be sexually dimorphic. Androgen uptake was more widespread than estrogen uptake in the brainstem. Brainstem nuclei that accumulated 5 alpha-dihydrotestosterone included the locus ceruleus, the dorsal raphe, the hypoglossal nucleus, the area postrema, the nucleus of the solitary tract, and the dorsal nucleus of the vagus.

Animals↗

PubMed1999

Real-time, sequence-specific detection of nucleic acids during strand displacement amplification.

Strand displacement amplification (SDA) is an isothermal nucleic acid amplification method based on the primer-directed nicking activity of a restriction enzyme and the strand displacement activity of an exonuclease-deficient polymerase. Here we describe fluorogenic reporter probes that permit real-time, sequence-specific detection of targets amplified during SDA. The new probes possess the single-strand half of a BsoBI recognition sequence flanked on opposite sides by a fluorophore and a quencher. The probes also contain target-binding sequences located 3' to the BsoBI site. Fluorophore and quencher are maintained in sufficiently close proximity that fluorescence is quenched in the intact single-stranded probe. If target is present during SDA, the probe is converted into a fully double-stranded form and is cleaved by the restriction enzyme BsoBI, which also serves as the nicking agent for SDA. Fluorophore and quencher diffuse apart upon probe cleavage, causing increased fluorescence. Target replication may thus be followed in real time during the SDA reaction. Probe performance may be enhanced by embedding the fluorogenic BsoBI site within the loop of a folded hairpin structure. The new probe designs permit detection of as few as 10 target copies within 30 min in a closed-tube, real-time format, eliminating the possibility of carry-over contamination. The probes may be used to detect RNA targets in SDA mixtures containing reverse transcriptase. Furthermore, a two-color competitive SDA format permits accurate quantification of target levels from the real-time fluorescence data.

Base Sequence↗

PubMed1988

Atropine infusions near the sexually dimorphic area of the gerbil hypothalamus facilitate hormonal induction of scent marking.

The sexually dimorphic area (SDA) of the gerbil hypothalamus contains cells in which acetylcholinesterase activity is stimulated by testosterone. These cells are probably cholinoceptive. Because cholinoceptive cells and the SDA are both implicated in hormonal control of gerbil scent marking, marking was studied in castrated males given a low dose of testosterone systemically, and atropine, a cholinergic antagonist, near the SDA. Controls received saline near the SDA or atropine in the thalamus. Subjects were also tested for male sexual behavior, since it is also affected by the SDA. Infusing 25-35 micrograms atropine methyl nitrate near the SDA twice a week facilitated marking but did not affect mating. Experimental males marked more, whereas controls marked less, while receiving infusions, than they did before castration. The two control groups did not differ from each other. After infusions stopped, marking by experimental males decreased, though residual effects were detected in one test setting. The data suggest that a cholinoceptive system in or near the SDA participates in hormonal control of gerbil scent marking.

Animals↗

PubMed1992

Spermine dialdehyde, a novel ex vivo purging agent for both allogenic and autologous bone marrow transplantations.

The use of ex vivo purging agents has shown to be beneficial for both allogeneic and autologous bone marrow transplantations. We have shown previously that spermine dialdehyde (SDA), an oxidized product of spermine, when used in phosphate-buffered saline (PBS) preferentially inhibits T-cell proliferation while sparing myeloid cells. Lethally irradiated mice were rescued by reconstitution with SDA-treated allogeneic marrow and showed no sign of graft-vs-host disease (GVHD). In this paper, we show by HPLC analysis that SDA degraded rapidly in PBS but remained intact in saline. Administered in saline, SDA was more inhibitory on leukemic cell lines than normal myeloid or T-cells. Lethally irradiated mice receiving a syngeneic bone marrow leukemic cell mixture treated ex vivo with SDA in saline did not manifest leukemia. Thus, the preferential inhibitory effect of SDA and its degraded products in different buffers suggest that SDA could act as a novel purging agent for both allogeneic and autologous bone marrow transplantations.

Acrolein↗