Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “STR”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,369 records · Page 76Linked to original sources
PubMed2001

Extent of ST-segment deviation in the single ECG lead of maximum deviation present 90 or 180 minutes after start of thrombolytic therapy best predicts outcome in acute myocardial infarction.

UNLABELLED: In evolving myocardial infarction the extent of ST segment deviation reflects the existing ischemic myocardial injury and thus conveys very useful early prognostic information. In recent years, the sum of ST segment elevation resolution (sum STR) has been proven to be an excellent early prognostic indicator. However, the predictive power of sum STR has never been systematically compared with that of other methods of evaluation of ST segment deviation recovery. We, therefore, proposed to compare the prognostic power of ST segment changes evaluated by either sum STR or by ST segment resolution in only the one lead showing the maximal deviation (lead STR) or only by the existing ST segment deviation in the single ECG lead of maximum ST deviation present at a given time point after thrombolysis (lead STE). METHODS AND RESULTS: In conjunction with the Intravenous nPA for Treatment of Infarcting Myocardium Early (InTIME) II Study, which compared mortality in patients with acute myocardial infarction randomized within 6 hours of symptom onset to receive either Lanoteplase or Alteplase, all 3593 German and Polish patients participated in an ST segment resolution substudy. A 12-lead ECG was recorded at baseline and at 90 and at 180 minutes after start of thrombolytic therapy. The areas under the receiver-operating characteristic (ROC) curves to compare the power to predict 30 day cardiac mortality for sum STR, lead STR, and lead STE were at 90 min 0.686, 0.714, and 0.761 (p < 0.002), and at 180 min 0.678, 0.703, and 0.755 (p < 0.001), respectively. In multivariate analysis lead STE was an independent predictor of outcome even when adjustment was made for sum STR, lead STR, and clinical variables. Cardiac mortality rates at 30 days for lead STE risk groups, classified as low, medium, or high (percent of patients in brackets), were at 90 min 1.0% (43%), 4.0% (32%), and 12.8% (25%), and at 180 min 1.5% (55%), 3.8% (31%), and 15.2% (14%), respectively. CONCLUSIONS: Simple measurement of the ST segment deviation existing in the one ECG lead with the greatest deviation on the ECG recorded 90 or 180 minutes after thrombolysis enables the identification of the major subsets of patients who are either at very low or exceptionally high risk of mortality.

Adult↗
PubMed2006

Therapeutic strategy for large vestibular schwannomas.

Management of large vestibular schwannoma (VS) remains a difficult problem for which the extent of tumor resection and the role of radiosurgery continue to be the subject of debate. To develop an optimal therapeutic strategy for large VS, various treatment options within the avenues of microsurgery and radiosurgery were evaluated and compared. The authors carefully reviewed the clinical data of 50 surgical cases of large VS, defined as tumors with an average diameter over 3 cm in magnetic resonance imaging (MRI). All patients underwent microsurgery as the primary treatment. Gross total removal (GTR) was achieved in nine patients (18%), near total removal (NTR) in 8 (16%), radical subtotal removal (R-STR) in 31 (62%), and subtotal removal (STR) in 2 (4%). Among the 33 patients with R-STR and STR, eight had undergone adjuvant radiosurgery for the residual mass. Average tumor volume and diameter were 26.8 cm(3) (13.5-55.1) and 36.4 mm (30.0-47.2), respectively. The mean follow-up duration was 113 months (58-167). The tumor control rate and facial nerve function according to the extent of removal were analyzed. The overall tumor control rate was 82%. Perfect tumor control was achieved after NTR and R-STR with adjuvant radiosurgery. However, 11% (1 of 9) of GTR patients and 32% (8 of 25) of R-STR-only and STR patients showed recurrence or regrowth. Overall favorable outcome of facial nerve function (H-B grade 1 or 2) was achieved in 78% of the patients. The facial nerve preservation rate was inversely proportional to the extent of tumor removal. NTR or R-STR with adjuvant radiosurgery might be acceptable therapeutic options for large VS in terms of achieving good tumor control and functional preservation of facial nerve.

Facial Nerve Injuries↗
PubMed1991

The scotopic threshold response of the cat ERG is suppressed selectively by GABA and glycine.

Corneal electroretinograms (ERGs) were recorded from anesthetized cats under scotopic conditions. We examined whether the scotopic threshold response (STR) of the ERG could be functionally distinguished from scotopic PII and a-wave using intravitreal application of neuroactive agents. We found that neurotransmitters with active sites on third order neurons had several different effects. Results were: (1) glycine and gamma-amino butyric acid (GABA) selectivity suppressed the STR but had relatively small and/or opposite effects on PII; (2) serotonin, acetylcholine and dopamine were nonselective and suppressed both STR and PII; (3) strychnine blocked the suppression of the STR by glycine. GABA-a antagonists alone only partially blocked GABA effects on the STR, and GABA-b antagonists were ineffective; (4) strychnine enhanced the STR. Bicuculline also increased STR amplitudes, but only in the presence of haloperidol. Our results suggest that the retinal pathway that contributes to the rod-driven STR is strongly influenced by cells that release glycine or GABA in the dark. These cells are possibly third order neurons in the retina. Our results also suggest that picrotoxin and bicuculline can facilitate the release of dopamine in the cat retina. Furthermore, the data indicate a light evoked release of dopamine which was first noticeable at about two log units above ERG threshold.

Acetylcholine↗
PubMed1993

In vivo electrochemical studies of gradient effects of (SC) cocaine on dopamine and serotonin release in dorsal striatum of conscious rats.

Cocaine (20 mg/kg) was administered subcutaneously (SC) to conscious male Sprague-Dawley rats after exploration in a novel chamber. (SC) cocaine was studied for its influence on in vivo dopamine (DA) and serotonin (5-HT) release in dorsal striatum (STr), with a further study of an anterior-posterior dorsal subdivision in a range of +/- 400 microns. Semiderivative voltammetry, a circuit for in vivo electrochemical biotechnologies, was used in combination with a stearate microelectrode to concurrently detect in separate electrochemical signals the electroactive species for DA and 5-HT in dorsal STr. The temporal resolution for detection was in the order of seconds. Concomitantly, cocaine-induced psychostimulant behaviors were studied with infrared photo beam detection. Psychostimulant behaviors classically thought to depend on DA--that is, hyperactivity (increased locomotor activity or ambulations), rearing, and finally stereotypy (fine movements of grooming and head bob)--and a 5-HT-ergic behavior, central ambulations, were monitored. The results showed that (SC) cocaine significantly (p < 0.0001) increased DA release in dorsal STr, whereas the overall effect of (SC) cocaine on 5-HT release was a significant increase (p < 0.0001) followed by an overall small (13%) but statistically significant decrease (p < 0.05). A dramatic cocaine-induced gradient effect on 5-HT release was seen in anterior-posterior dorsal STr, where 5-HT release was significantly (p < 0.0001) increased throughout the entire time period of study. Classically DA-dependent behaviors were significantly and positively correlated with increased DA release in dorsal STr and anterior-posterior dorsal STr (p < 0.001) in the 4-h period of study. However, 5-HT release after cocaine in the anterior-posterior dorsal STr was significantly and positively correlated with the classically DA-dependent behaviors as well (p < 0.001), implicating a role for 5-HT in the effectuation of cocaine-induced psychostimulant behavior. Generally, the 5-HT-ergic response to cocaine was enhanced before the DA-ergic response. Therefore, the data show that 5-HT as well as DA plays a role in the underlying mechanism of action of cocaine in dorsal STr. The data suggest that 5-HT may play a compensatory or adaptive role in the modulation of cocaine-induced nigrostriatal DA-ergic regulation.

Animals↗
PubMed2006

Relation of hyperglycemia to ST-segment resolution after reperfusion for acute myocardial infarction (from Observatoire des Infarctus de Côte-d'Or Survey [RICO]).

Hyperglycemia has been shown to be a powerful predictor of worse outcome after ST-segment-elevation myocardial infarction (STEMI), which could be related to impaired myocardial reperfusion. This study investigated the association between hyperglycemia and ST-segment resolution (STR) after thrombolysis. From the French regional Observatoire des Infarctus de Côte-d'Or survey, admission glucose in 371 patients with STEMIs who were treated by lysis<12 hours was analyzed. The single worst lead electrocardiogram before and 90 minutes after lysis was analyzed, and patients were divided into 3 groups according to the degree of STR: none (<30%), partial (30% to 70%), or complete (>or=70%). Of the 371 patients, 101 (27.2%) had no STR, 124 (33.4%) had partial STR, and 146 (39.4%) had complete STR. STR decreased with increasing glycemia (p=0.029), and patients with hyperglycemia (glycemia>or=11 mmol/L) were more likely to have no STR. Moreover, hyperglycemia was an independent predictor of incomplete STR even after adjustment for potential confounders (odds ratio 2.348, 95% confidence interval 1.212 to 4.547). In conclusion, the present study suggests a strong association between hyperglycemia and electrocardiographic signs of reperfusion in patients with STEMIs after lysis and suggests the usefulness of evaluating early glycemic control in the setting of reperfusion for acute myocardial infarction.

Aged↗
PubMed2003

Large variability in synaptic N-methyl-D-aspartate receptor density on interneurons and a comparison with pyramidal-cell spines in the rat hippocampus.

Pyramidal cells receive input from several types of GABA-releasing interneurons and innervate them reciprocally. Glutamatergic activation of interneurons involves both alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-D-aspartate (NMDA) type glutamate receptors expressed in type I synapses, mostly on their dendritic shafts. On average, the synaptic AMPA receptor content is several times higher on interneurons than in the spines of pyramidal cells. To compare the NMDA receptor content of synapses, we used a quantitative postembedding immunogold technique on serial electron microscopic sections, and analysed the synapses on interneuron dendrites and pyramidal cell spines in the CA1 area. Because all NMDA receptors contain the obligatory NR1 subunit, receptor localisation was carried out using antibodies recognising all splice variants of the NR1 subunit. Four populations of synapse were examined: i). on spines of pyramidal cells in stratum (str.) radiatum and str. oriens; ii). on parvalbumin-positive interneuronal dendritic shafts in str. radiatum; iii). on randomly found dendritic shafts in str. oriens and iv). on somatostatin-positive interneuronal dendritic shafts and somata in str. oriens. On average, the size of the synapses on spines was about half of those on interneurons. The four populations of synapse significantly differed in labelling for the NR1 subunit. The median density of NR1 subunit labelling was highest on pyramidal cell spines. It was lowest in the synapses on parvalbumin-positive dendrites in str. radiatum, where more than half of these synapses were immunonegative. In str. oriens, synapses on interneurons had a high variability of receptor content; some dendrites were similar to those in str. radiatum, including the proximal synapses of somatostatin-positive cells, whereas others had immunoreactivity for the NR1 subunit similar to or higher than synapses on pyramidal cell spines. These results show that synaptic NMDA receptor density differs between pyramidal cells and interneurons. Some interneurons may have a high NMDA receptor content, whereas others, like some parvalbumin-expressing cells, a particularly low synaptic NMDA receptor content. Consequently, fast glutamatergic activation of interneurons is expected to show cell type-specific time course and state-dependent dynamics.

Animals↗
PubMed2000

Saturation transfer ratio imaging in invasive ductal carcinomas of the breast.

A prospective study was performed to investigate the correlations between saturation transfer ratio (STR) and histologic parameters of invasive ductal carcinomas in human breast. The histologic parameters investigated were the extent of fibrosis in the intercellular matrix, dysplastic changes of nuclei, and mitotic index. Twenty-seven patients with breast carcinoma were examined using an off-resonance saturation pulse in conjunction with conventional field-echo T(1)-weighted imaging at frequency offsets of 448 Hz and 1200 Hz from water resonance. The values of STR at frequency offset of 1200 Hz (STR(1200)) increased from non-scirrhous carcinoma to scirrhous carcinoma. Although STR(1200) showed correlation with the extent of fibrosis in the intercellular matrix (p<0.01, n = 27), they did not correlate with the dysplastic changes of nuclei or mitotic index. On the other hand, the values of STR at frequency offset of 448 Hz (STR(448)) demonstrated close correlation to dysplastic changes of nuclei and mitotic index (p<0.01, n = 27). STR(1200) correlates with the structural characteristics and STR(448) correlates with the nature of malignant cells with regard to nuclear dysplasia and mitotic potential.

Adenocarcinoma, Scirrhous↗
PubMed2004

Impact of age and duration on sight-threatening retinopathy in South Asians and Caucasians attending a diabetic clinic.

AIMS: To examine diabetic retinopathy in Asians and Caucasians attending a hospital diabetic clinic and to evaluate the impact of the significant risk factors on the probability of sight-threatening retinopathy. METHODS: A total of 500 diabetic patients (268 Asians, 232 Caucasians) who attended a diabetic clinic within a defined time period were examined for severity of diabetic retinopathy. The existence of sight-threatening retinopathy (STR) was compared in the two groups. Significant risk factors such as age, duration and hypertension were analysed against the probability of STR in each of the two races. RESULTS: Asians demonstrated significantly higher rates of STR. Univariate analysis showed age, duration, race, gender, and insulin-requiring status to be significantly associated with STR. Multivariate logistic regression showed a significant association of STR with race, age and duration of diabetes, with no significant interaction effects between variables. The logistic regression model predicted STR in Asians to be matched to that in Caucasians by a 12.5-year difference factor; that is, Caucasians were older by 12.5 years or had a 12.5-year longer duration than Asians for the same level of STR. CONCLUSIONS: After adjusting for age and duration of diabetes, the probability of STR in Asian diabetic patients attending the diabetic clinics in Bradford is significantly higher than that in Caucasians (odds ratio=3.184, P<0.05). The impact of age and duration was significantly higher in patients of South Asian origin compared to Caucasians.

Adult↗
PubMed2026

Atypical short tandem repeat allelic patterns in a sexual assault case involving hematopoietic stem cell transplantation.

Short tandem repeat (STR) profiling is a cornerstone of forensic DNA analysis, particularly during criminal investigations. However, certain clinical conditions, such as bone marrow transplantation, can complicate interpretation. To illustrate the impact of allogeneic bone marrow transplantation on forensic STR analysis, this case report details a sexual assault investigation involving a female victim who had previously received a bone marrow transplant from a female donor. A female sexual assault victim underwent forensic examination, during which multiple biological swabs were collected. STR profiling was conducted on the victim's blood, fingernail, buccal, breast, hip, vulvar, vaginal, cervical samples, panty, and brassiere. As conflicting profiles were found, a detailed medical history was collected, and hair follicle analysis was performed to confirm the origin of the STR profiles. Blood STR profiling revealed a single female genotype, while multiple swabs, including vaginal and cervical samples, showed a second female STR profile alongside the first. Notably, the consistency and distribution of the mixed profile across samples reduced the likelihood of laboratory contamination. The medical history of the victim revealed a prior history of allogeneic bone marrow transplant. Hair follicle analysis identified the recipient's original genotype, confirming that the secondary STR profile originated from the donor. Bone marrow transplantation may result in a mixed STR profile, potentially leading to misidentification or misinterpretation of forensic evidence. Awareness of transplant history is crucial during forensic evaluations. However, such clinical history is currently not included in standard sexual-assault evidence forms, underscoring the need for procedural updates.

Female↗
PubMed2006

Genetics and genomics of core short tandem repeat loci used in human identity testing.

Over the past decade, the human identity testing community has settled on a set of core short tandem repeat (STR) loci that are widely used for DNA typing applications. A variety of commercial kits enable robust amplification of these core STR loci. A brief history is presented regarding the selection of core autosomal and Y-chromosomal STR markers. The physical location of each STR locus in the human genome is delineated and allele ranges and variants observed in human populations are summarized as are mutation rates observed from parentage testing. Internet resources for additional information on core STR loci are reviewed. Additional topics are also discussed, including potential linkage of STR loci to genetic disease-causing genes, probabilistic predictions of sample ethnicity, and desirable characteristics for additional STR loci that may be added in the future to the current core loci. These core STR loci, which form the basis for DNA databases worldwide, will continue to play an important role in forensic science for many years to come.

Alleles↗
PubMed2004

New support for clarifying the relation between ST segment resolution and microvascular function: degree of ST segment resolution correlates with the pressure derived collateral flow index.

OBJECTIVE: To investigate the relation between the degree of ST segment resolution (STR) after thrombolysis and the pressure derived collateral flow index (CFIp), determined using an intracoronary pressure measurement technique in patients with recent myocardial infarction. METHODS: 33 patients were studied. TIMI grade III flow was achieved in the infarct related artery by thrombolysis. A surface ECG was obtained on admission and 90 minutes later. The sum of ST segment elevations was measured by summing all leads with ST elevation on the baseline ECG and on the 90 minute ECG (after thrombolysis) and calculating the percentage recovery. The study population was divided into two groups, with good STR (> or = 50%; group 1) or poor STR (< 50%; group 2). After angiography, a fibreoptic pressure monitoring guidewire was advanced to the stenosis to be dilated. The CFIp was determined as the ratio [coronary wedge pressure - central venous pressure]/[mean aortic pressure - central venous pressure]. RESULTS: The mean STR on the surface ECG was 54.6% and mean (SD) CFIp was 0.25 (0.12) (range 0.10-0.41). There was an inverse correlation between the individually calculated percentage of STR and CFIp (r = -0.64, p < 0.01). The mean CFIp was lower in patients with a good STR than in those with a poor STR (0.18 (0.07) v 0.27 (0.10), p < 0.02). CONCLUSIONS: Although TIMI grade III flow was achieved after thrombolysis, a worse STR on the surface ECG was associated with higher CFIp measured in the infarct related artery. CFIp appears to reflect the degree of microvascular obstruction by quantifying impedance of the microvasculature.

Blood Pressure↗
PubMed2026

Detection of short tandem repeats in the cattle genome: a comparison of bioinformatic tools.

BACKGROUND: Short tandem repeats (STRs) are repetitive DNA sequences with 1&#x2013;6 nucleotide repeat units, exhibiting high polymorphism due to varying repeat counts. STRs are more variable than SNPs and can cause genetic disorders. With population-scale cattle whole-genome sequencing data available, whole-genome STR identification has attracted new interest, but challenges remain due to the lack of standardized methods, sequencing data limitations, and the diversity of STR-calling tools. This study compared six STR-calling tools: HipSTR, GangSTR, and ExpansionHunter for short-read data, and Straglr, RepeatHMM, and LongTR for Oxford Nanopore (ONT) long-read data&#x2014;using sequences from five Holstein cattle (two parent&#x2013;offspring trios with a shared sire). This is the first cattle study to evaluate short- and long-read STR callers using both data types from the same animals. RESULTS: In short-read data, ExpansionHunter identified the highest number of polymorphic STRs (pSTRs) (327,690), followed by HipSTR (205,900) and GangSTR (110,680), with 93,023 loci detected by all three tools. In long-read data, LongTR detected 470,250 pSTRs, RepeatHMM 224,185, and Straglr 90,275, with only 33,253 loci shared among them. Mendelian consistency of STR genotypes in the trio offspring was high (>&#x2009;0.8) for all short-read tools, with HipSTR and GangSTR highest at 0.98. LongTR was the only long-read tool with high consistency (0.88). Short-read tools also showed higher concordance in STR genotypes among themselves than was observed among long-read tools. However, long-read tools had a clear advantage in detecting large STRs. Relative to computational efficiency, HipSTR and GangSTR (short-reads), and LongTR (long-reads) required less memory and shorter runtimes than the other tools. CONCLUSIONS: Tool selection is critical for accurate whole-genome STR identification in cattle. For short-read data, HipSTR showed relatively high Mendelian consistency and concordance compared to the other tools, while ExpansionHunter was able to detect longer STRs but with lower Mendelian consistency. For long-read data, LongTR demonstrated higher consistency and computational efficiency relative to the other tools. Based on these results, HipSTR and LongTR are suggested as preferred options for short-read and ONT long-read datasets, respectively, in cattle STR analysis. These recommendations are based on the metrics observed in this study, and confirmatory analyses across additional breeds, larger sample sizes, and validated truth sets are encouraged.

Animals↗
PubMed1997

Paraneoplastic myasthenia gravis: detection of anti-MGT30 (titin) antibodies predicts thymic epithelial tumor.

It has been suggested that antibodies against non-acetylcholine receptor proteins of striated muscle are markers of the presence of a thymic epithelial tumor in patients with myasthenia gravis (MG). These antibodies may be measured using an immunofluorescence assay against striated muscle (anti-STR) or an ELISA with a recombinant 30-kd titin fragment (anti-MGT30). To directly compare anti-STR with anti-MGT30, we examined the sera of 276 consecutive patients with known or suspected MG. Definite diagnoses and thymic histology, if available, were correlated with the antibody assays. Of the 276 patients, 164 had MG. Thymic histology was obtained in 44 patients: 18 had lymphofollicular hyperplasia, 13 thymic epithelial tumors, 8 atrophy, and 5 were normal. When compared with anti-STR, anti-MGT30 showed a sensitivity of 69% (STR 77%), specificity of 100% (STR 56%, p = 0.026), negative predictive value of 82% (STR 77%), and positive predictive value of 100% (STR 56%, p = 0.003) for the identification of a thymic epithelial tumor versus thymic hyperplasia. We conclude that the anti-MGT30 ELISA is better than the anti-STR immunofluorescence assay for the diagnosis of paraneoplastic MG.

Autoantibodies↗
PubMed1995

Comparative effectiveness of somatotropin and anabolic steroids in feedlot steers.

Crossbred steers (n = 252, BW = 379 +/- 28 kg) were allotted to 42 pens in a 2 x 3 factorial arrangement of treatments: control or steroid implant (STR; estradiol benzoate+progesterone [three lighter blocks reimplanted on d 84] and trenbolone acetate [reimplanted on d 63]), and either 0, 80, or 160 mg/wk of recombinant bovine somatotropin (bST). Steers were adapted to the finishing diet (12% roughage equivalent, 13% CP) before the start of the experiment and fed for 84 or 119 d. Blood samples were taken on d 0, 14, 28, 56, and 84 for plasma urea N (PUN), serum somatotropin (ST), plasma insulin-like growth factor I (IGF-I), and plasma amino acid assay. Few interactions were noted (P > .1). Gain was increased by both treatments: 1.30 vs 1.66 kg/d for control vs. STR (P < .001) and 1.44, 1.49, and 1.51 kg/d (linear, P = .07) for 0, 80, and 160 mg of bST/wk, respectively. Gain efficiency was also improved: 169 vs 205 g/kg (P < .001) and 177, 189, and 195 g/kg (linear, P < .001), respectively. Average PUN was decreased (P < .001) 29% by STR and decreased 17 and 29% by 80 and 160 mg of bST/wk, respectively (linear, P < .001). Somatotropin decreased mean serum ST compared with controls; STR increased ST 36% compared with controls. Average plasma IGF-I was increased (P < .001) 12% by STR and 13 and 19% (linear, P < .001) by 80 and 160 mg of bST/wk, respectively. Both STR and bST influenced (P < .05) plasma amino acid profiles. Indicators of carcass fatness were decreased linearly (P < .05) by bST; STR implant tended to decrease carcass fatness and increase longissimus muscle area, which was related to carcass weight. The anabolic effects of STR and bST were found to be additive and possibly independent in feedlot steers.

Amino Acids↗
PubMedDate not supplied

[Influence of products of thermophilous methane fermentation on the mixed lactic acid bacterial culture].

The effect of products resulting from thermophilous methane fermentation on the accumulation and ratio of different lactic acid bacteria (Str. lactis, Str. cremoris, Str. diacetilactis, Str. diacetil. var. acetoinicus, Leuc. citrovorum8 L. plantarum) was investigated upon their combined cultivation in milk and serum. In combined cultivation of the streptococcal culture the rate of growth of a single strain differed from that in separate cultivation. Str. cremoris was accumulated with the highest rate during its separate cultivation and with the lowest rate during its combined cultivation. An addition of products of thermophilous methane fermentation to the combined culture of streptococci of different strains increased the growth rate and accumulation of each strain. At the same time the products influenced differently the quantitative ratios of various strains in the resulting biomass. For instance, the relative content of Str. cremoris and Leuc. citrovorum decreased insignificantly and that of Str. lactis and Str. diacetil. var. acetoin.increased. The combined cultivation of the five streptococcal strains with L. plantarum in the medium containing no additions of thermophilous methane fermentation products increased the relative content of L. plantarum from the beginning of fermentation. In the medium containing the additions of this parameter varied sinusoidally with a minimum of 6 to 9 hours. Possible mechanisms of these changes are discussed.

Culture Media↗
PubMed2003

Contribution of scatter and attenuation compensation to SPECT images of nonuniformly distributed brain activities.

UNLABELLED: Correction of scatter and attenuation is essential for quantitative SPECT. In this work, we evaluated the accuracy gained from a method of transmission-dependent convolution subtraction (TDCS) in the quantitation of activity that is highly concentrated in the striatum (STR). METHODS: SPECT data were acquired from an (123)I-containing phantom with a constant activity in the STR but differing background (BKG) activities, so as to simulate various STR/BKG ratios (19.7:1, 9.7:1, 4.8:1, 1.9:1, and 1:1). In a study of healthy humans (n = 6), a transmission scan followed by an emission scan was performed 24 h after injection of (123)I-2beta-carbomethoxy-3beta-(4-iodophenyl)-tropane ((123)I-beta-CIT). All SPECT data was reconstructed with ordered-subset expectation maximization. TDCS was applied for scatter correction. Values of activity in the STR and occipital lobe (for BKG) were used to calculate binding potential V(3)" (= [STR - BKG]/BKG). The effect of SPECT collimator dependency on scatter correction was also evaluated for 6 collimators from 3 different SPECT cameras in the phantom experiment. RESULTS: Scatter correction in the phantom experiment increased the measured values of STR activity (36.2%), resulting in a substantial increase in V(3)" (66.1%). Scatter and attenuation corrections with recovery correction showed an overall bias of -7.3% for the STR, -4.0% for BKG activity, and -7.8% for V(3)". TDCS corrections of phantom activities were relatively uniform for the 6 different collimators, with variabilities of <5.5% for the STR and <3.0% for BKG activities. TDCS correction of human (123)I-beta-CIT images was of a similar, although slightly larger, magnitude than for the phantom data, with increased V(3)" values of 9.4 +/- 2.3 and 4.9 +/- 0.6, with and without scatter correction, respectively. CONCLUSION: The TDSC method significantly improved the accuracy of SPECT images with a nonuniform distribution of activity highly concentrated in central regions. The value of V(3)" was significantly increased in phantom and human data, with most of the improvement derived from an increase in STR activity. This scatter correction method was approximately equally useful with data from the 6 different collimators and is recommended for more accurate quantitation of nonuniformly distributed brain activities.

Adult↗
PubMed2003

[Analysis on genetic polymorphism of 14 short tandem repeat loci on chromosome 7p14-15 and 12q13 in Chinese north Hans].

OBJECTIVE: To analyze the genetic polymorphism of 6 short tandem repeat (STR) loci on chromosome 7p14-15 and 8 STR loci on chromosome 12q13 in Chinese north Hans. METHODS: Fluorescence-labeling polymerase chain reaction and capillary electrophoresis were used to analyze the genetic polymorphism of 100 randomly selected individuals from Chinese north Han nationality at 6 STR loci (D7S1808, D7S2250, D7S2251, D7S683, D7S656 and D7S528) on chromosome 7p14-15 and 8 STR loci(D12S1056, D12S1293, D12S83, D12S1655, D12S1662, D12S334, D12S137 and D12S102) on chromosome 12q13. RESULTS: In the Chinese north Han population, 7 alleles and 24 genotypes, 8 alleles and 27 genotypes, 7 alleles and 22 genotypes, 4 alleles and 10 genotypes, 6 alleles and 17 genotypes, 5 alleles and 13 genotypes were observed at D7S1808, D7S2250, D7S2251, D7S683, D7S656 and D7S528. The heterozygosities at the above 6 STR loci were 86%, 88%, 83%, 79%, 85% and 80%, respectively. Five alleles and 15 genotypes, 5 alleles and 15 genotypes, 8 alleles and 29 genotypes, 6 alleles and 17 genotypes, 6 alleles and 17 genotypes, 6 alleles and 19 genotypes, 5 alleles and 13 genotypes, 7 alleles and 24 genotypes were observed at D12S1056, D12S1293, D12S83, D12S1655, D12S1662, D12S334, D12S137 and D12S102. The heterozygosities at the above 8 STR loci were 86%, 84%, 87%, 82%, 84%, 85%, 81% and 89%, respectively. CONCLUSION: The distributions of allele frequencies of 6 STR loci on chromosome 7p14-15 and of 8 STR loci on chromosome 12q13 were consistent with the Hardy-Weinberg equilibrium. The highly genetic polymorphism was observed in Chinese north Han population.

Asian People↗
PubMed2003

Relationship between cardiotonic effects and inhibition on cardiac sarcolemmal Na+,K+-ATPase of strophan-thidin at low concentrations.

AIM: To evaluate the effects of strophanthidin (Str) on cardiac contractile function and sarcolemmal Na+, K+-ATPase activities in isolated guinea-pig hearts. METHODS: Isolated guinea-pig hearts were perfused through aorta in a Langendorff mode. Heart rate (HR), left ventricular pressure (LVP), and first derivatives (+/-dp/dt(max)) of LVP were recorded by eight-channel physiological instrument. Cardiac sarcolemmal Na+, K+-ATPase activities were determined with colorimetry. RESULTS: Str 0.1 nmol/L stimulated the Na+, K+-ATPase activities (P<0.05), but had no effect on HR, LVP, and +/-dp/dt(max). Str 1 nmol/L increased +dp/dt(max) (P<0.05) and Na+, K+-ATPase activities (P<0.01). Str 10 and 100 nmol/L significantly increased both LVP (P<0.05) and +dp/dt(max) (P<0.05 or P<0.01), and had no significant effects on Na+, K+-ATPase activities. However, Str 1-100 micromol/L at first enhanced the LVP and +dp/dtmax (P<0.01), then reduced them resulting from irregular contraction, and effects of Str on Na+, K+-ATPase activities revealed a concentration-dependent inhibition (P<0.01). CONCLUSION: The positive inotropic effects and irregular contraction produced by Str at higher concentrations result from the inhibition of Na+, K+-ATPase activities, and the positive inotropic effects of Str at lower concentrations are not related to the inhibition of the Na+, K+-ATPase activities.

Animals↗