[Progress in health effects and measurement standards of ultraviolet radiation in the workplace].

Ultraviolet radiation affects human health. On the one hand, moderate amounts of UV radiation can promote human health and have the effect of promoting vitamin D production; but on the other hand, excessive UV radiation can also cause adverse effects on human skin and eyes, such as causing skin photoaging, skin cancer, electrophthalmia and cataracts to occur. Therefore, the measurement of ultraviolet radiation is extremely important. This paper mainly reviews the health effects of ultraviolet radiation and the progress of measurement standards in the workplace, and puts forward suggestions on the revision of the existing standards from five aspects including use new measuring instruments and methods, improve the existing measuring instruments, specify the number of measurements, expand the scope of application of the standards and consider the influence of the sun on the measurement of artificial ultraviolet radiation, so as to provide reference for the revision of new standards.

[Effects of remote ischemic preconditioning on contrast-induced acute kidney injury after percutaneous coronary intervention in patients with chronic total occlusion].

Objective: To investigate the effect of remote ischemic preconditioning (RIPC) on contrast-induced acute kidney injury (CI-AKI) in patients with chronic total occlusion (CTO) after percutaneous coronary intervention (PCI). Methods: A total of 282 patients undergoing PCI at Zhongda Hospital Affiliated to Southeast University between June 2017 and January 2019 were prospectively enrolled. The patients were randomly divided into RIPC group (n=142) and control group (n=140). CI-AKI was defined as an increase in level of cystatin C (CysC)≥10% above baseline at 24 h after contrast administration. Baseline characteristics and the incidence of CI-AKI were compared between the two groups. The multivariate logistic regression analysis was further used to analyze the independent risk factors of CI-AKI. Results: There were no significant differences in age, gender, smoking, hypertension, diabetes, stroke and old myocardial infarction, coronary artery bypass graft surgery, previous PCI history and laboratory test indicators, target vessel and pathological characteristics of CTO lesions, contrast agent dosage, J-CTO (Multicenter CTO Registry in Japan) score, SYNTAX (Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery) score, PCI success rate and stent number between the two groups (P>0.05). The incidence of CI-AKI was significantly lower (18.3% vs 29.3%, P=0.036) in RIPC group than that of control group. Multivariate logistic analysis found that creatinine [odds ratio (OR)=1.018,95%CI: 1.006-1.030, P=0.003], CysC (OR=5.200, 95%CI:2.714-9.963, P<0.001),contrast agent dosage (OR=1.013,95%CI: 1.007-1.019, P<0.001) and J-CTO score (OR=1.834, 95%CI: 1.145-2.939, P=0.012) were independent risk factors of CI-AKI. However, RIPC was an independent protective factor of CI-AKI (OR=0.391, 95%CI: 0.199-0.765, P=0.006). Conclusion: RIPC before contrast agent administration prevents CI-AKI in CTO patients undergoing PCI.

Arterial spin labelling MRI for detecting pseudocapsule defects and predicting renal capsule invasion in renal cell carcinoma.

AIM: To evaluate prospectively the performance of combining morphological and arterial spin labelling (ASL) magnetic resonance imaging (MRI) for detecting pseudocapsule defects in renal cell carcinoma (RCC), and to predict renal capsule invasion confirmed histopathologically. MATERIALS AND METHODS: Twenty consecutive patients with suspicious renal tumours underwent MRI. Renal ASL imaging was performed and renal blood flow was measured quantitatively. The diagnostic performance of T2-weighted images alone, and a combination of T2-weighted and ASL images for predicting renal capsule invasion were assessed. RESULTS: Twenty renal lesions were evaluated in 20 patients. All lesions were clear cell RCCs (ccRCCs) confirmed at post-surgical histopathology. Fifteen ccRCCs showed pseudocapsule defects on T2-weighted images, of which 12 cases showed existing blood flow in defect areas on perfusion images. To predict renal capsule invasion, the sensitivity, specificity, positive predictive value, and negative predictive value were 100%, 71.4%, 86.7%, 100%, respectively, for T2-weighted images alone, and 92.3%, 100%, 100%, 87.5%, respectively, for the combination of T2-weighted and ASL images. CONCLUSION: ASL images can reflect the perfusion of pseudocapsule defects and as such, the combination of T2-weighted and ASL images produces promising diagnostic accuracy for predicting renal capsule invasion.

Glucose and lipid effects of the ileal apical sodium-dependent bile acid transporter inhibitor GSK2330672: double-blind randomized trials with type 2 diabetes subjects taking metformin.

AIMS: To investigate the pharmacodynamics, pharmacokinetics and safety/tolerability of blocking reuptake of bile acids using the inhibitor GSK2330672 (GSK672) in patients with type 2 diabetes (T2D). METHODS: Subjects with T2D taking metformin were enrolled in two studies in which they took metformin 850 mg twice daily for 2 weeks prior to and during the randomized treatment periods. In the first crossover study (n = 15), subjects received GSK672 45 mg, escalating to 90 mg, twice daily, or placebo for 7 days. The second parallel-group study (n = 75) investigated GSK672 10-90 mg twice daily, placebo or sitagliptin for 14 days. RESULTS: In both studies, GSK672 reduced circulating bile acids and increased serum 7-α-hydroxy-4-cholesten-3-one (C4), an intermediate in the hepatic synthesis of bile acids. Compared with placebo, in the parallel-group study 90 mg GSK672 twice daily reduced fasting plasma glucose [FPG; -1.21 mmol/l; 95% confidence interval (CI) -2.14, -0.28] and weighted-mean glucose area under the curve (AUC)0-24 h (-1.33 mmol/l; 95% CI -2.30, -0.36), as well as fasting and weighted-mean insulin AUC0 -24 h . GSK672 also reduced cholesterol (LDL, non-HDL and total cholesterol) and apolipoprotein B concentrations; the maximum LDL cholesterol reduction was ∼40%. There was no change in HDL cholesterol but there was a trend towards increased fasting triglyceride levels in the GSK672 groups compared with placebo. In both studies, the most common adverse events associated with GSK672 were gastrointestinal, mostly diarrhoea (22-100%), which appeared to be independent of dose. CONCLUSIONS: In subjects with T2D on metformin, GSK672 improved glucose and lipids, but there was a high incidence of gastrointestinal adverse events.

[Feasibility study of dynamic contrast enhanced magnetic resonance imaging qualitative diagnosis of musculoskeletal tumors].

OBJECTIVE: To investigate the feasibility of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters in differentiating musculoskeletal tumors with different behaviours of pathological findings before therapy. METHODS: A total of 34 subjects of musculoskeletal tumors were involved in this retrospective analysis. DCE-MRI was performed using a fat-saturated 3D VIBE (volumetric interpolated breath-hold exam) imaging sequence with following parameters: FA, 10 degree; TR/TE, 5.6/2.4 ms; slice thickness, 4.0 mm with no intersection gap; field of view, 310 mm×213 mm; matrix, 256×178; voxel size, 1.2 mm×1.2 mm×4.0 mm; parallel imaging acceleration factor. The actuation time for the DCE-MRI sequence was 255 s with a temporal resolution of 5 s and 40 image volumes. Using pathological results as a gold standard, tumors were divided into benign, borderline and malignant tumors. Toft's model was used for calculation of K(trans) (volume transfer constant), Ve (extravascular extracellular space distribute volume per unit tissue volume) and Kep (microvascular permeability reflux constant). Those parameters were compared between the lesions and the control tissues using paired t tests. The one-way analysis of variance was used to assess the difference among benign, borderline and malignant tumors. P values <0.05 difference was statistically significant. RESULTS: Based on the WHO Classification of Tumours of Soft Tissue and Bone(2012) criteria, 34 patients were divided into three groups: 11 for benign tumors, 12 for borderline tumors, and 11 for malignancies. Compared with control tissues, K(trans) and Kep showed no difference, but Ve was increased in benign tumors, Kep showed no difference, but K(trans) and Ve were increased in borderline tumors,K(trans), Kep and Ve were increased in malignant tumors. K(trans) (P<0.001) and Kep (P<0.01) were significantly higher in malignant tumors than in benign and borderline tumors, but did not show any difference between benign tumors and borderline tumors. Ve was significantly higher in malignant tumors than in benign (P<0.05), but did not show any difference between malignant and borderline tumors, benign tumors and borderline tumors (P>0.05). CONCLUSION: DCE-MRI technique is useful to evaluate the pathological behaviour of musculoskeletal tumors. The quantitative analysis of DCE parameters in conjunction with conventional MR images can improve the accuracy of musculoskeletal tumor qualitative analysis.

Non-HDL-cholesterol to HDL-cholesterol ratio as an independent risk factor for the development of chronic kidney disease.

BACKGROUND AND AIMS: Dyslipidemia contributes to the development and progression of renal disease. The objective of this study was to investigate whether an elevated non-HDL-cholesterol to HDL-cholesterol ratio (NonHDLc/HDLc) predicts new-onset chronic kidney disease (CKD). METHODS AND RESULTS: We followed 1891 Chinese adults with normal or near-normal kidney function at baseline who participated in an annual health checkup program for the occurrence of new-onset CKD [defined as an estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73 m(2) (low eGFR) and/or proteinuria (defined as urinary protein ≥1 + on dipstick testing)] or low eGFR. Cox proportional hazards models were used to examine the independent relationship between the plasma NonHDLc/HDLc ratio and new-onset CKD. During a median follow-up period of 2.8 years, 3% (n = 57) of participants developed new-onset CKD. Compared with patients in the lowest tertile, patients with NonHDLc/HDLc ratios in the highest tertile had a 1.45-fold higher risk of new-onset CKD (hazard ratio [HR], 2.45; 95% confidence interval [95% CI], 1.07 to 5.61; P = 0.035) after adjustment for potential confounders. There was a marginally significant association with low eGFR (tertile 3 versus tertile 1: HR, 2.94; 95% CI, 0.98 to 8.82; P = 0.054). CONCLUSIONS: NonHDLc/HDLc ratio is an independent risk factor for the development of CKD. Assessment of NonHDLc/HDLc ratio may help identify high risk groups with chronic kidney disease.

CD133 positive cells isolated from A549 cell line exhibited high liver metastatic potential.

Lung cancer remains a major cause of cancer-related lethality because of high incidence and recurrence in spite of significant advances in staging and therapy. In present study, we identified a subpopulation of cells isolated from the A549 cell line with marker CD133. In vivo results showed that A549 CD133+ cells displayed high liver metastatic potential. Severe liver cell damage with tumor cell invasion revealed by pathological examination and these changes were consistent with the results of serological tests where the plasma GPT and GOT level are significantly higher than that of the control group. Compared with A549 cells, A549 CD133+ cells expressed high levels of VEGF and exhibited high migration and invasion capability. In conclusion, we first reported that A549 CD133+ cells exhibited characteristic of high liver metastatic potential which makes it be a suitable model for further study of liver metastasis of lung adenocarcinoma and provide a potential platform for anti-metastatic drug discovery or evaluation.

Development of a population pharmacokinetic model to describe azithromycin whole-blood and plasma concentrations over time in healthy subjects.

Azithromycin (AZI), a broad-spectrum antibiotic, accumulates in polymorphonuclear cells and peripheral blood mononuclear cells. The distribution of AZI in proinflammatory cells may be important to the anti-inflammatory properties. Previous studies have described plasma AZI pharmacokinetics. The objective of this study was to describe the pharmacokinetics of AZI in whole blood (concentration in whole blood [Cb]) and plasma (concentration in plasma [Cp]) of healthy subjects. In this study, 12 subjects received AZI (500 mg once a day for 3 days). AZI Cb and Cp were quantified in serial samples collected up to 3 weeks after the last dose and analyzed using noncompartmental and compartmental methods. After the last dose, Cb was greater than Cp. Importantly, Cb, but not Cp, was quantifiable in all but one subject at 3 weeks. The blood area under the curve during a 24-h dosing interval (AUC24) was ∼2-fold greater than the plasma AUC24, but simulations suggested that Cb was not at steady state by day 3. Upon exploration of numerous models, an empirical 3-compartment model adequately described Cp and Cb, but Cp was somewhat underestimated. Intercompartmental clearance (CL; likely representing cells) was lower than apparent oral CL (18 versus 118 liters/h). Plasma, peripheral, and cell compartmental volumes were 439 liters, 2,980 liters, and 3,084 liters, respectively. Interindividual variability in CL was low (26.2%), while the volume of distribution variability was high (107%). This is the first report to describe AZI Cb in healthy subjects, the distribution parameters between Cp and Cb, and AZI retention in blood for up to 3 weeks following 3 daily doses. The model can be used to predict Cb from Cp for AZI under various dosing regimens. (This study has been registered at ClinicalTrials.gov under registration no. NCT01026064.).

Additional flight delays and magnetospheric-ionospheric disturbances during solar storms.

Although the sun is really far away from us, some solar activities could still influence the performance and reliability of space-borne and ground-based technological systems on Earth. Those time-varying conditions in space caused by the sun are also called solar storm or space weather. It is known that aviation activities can be affected during solar storms, but the exact effects of space weather on aviation are still unclear. Especially how the flight delays, the top topic concerned by most people, will be affected by space weather has never been thoroughly researched. By analyzing huge amount of flight data (~ 4 × 106 records), for the first time, we quantitatively investigate the flight delays during space weather events. It is found that compared to the quiet periods, the average arrival delay time and 30-min delay rate during space weather events are significantly increased by 81.34% and 21.45% respectively. The evident negative correlation between the yearly flight regularity rate and the yearly mean total sunspot number during 22 years also confirms such correlation. Further studies show that the flight delay time and delay rate will monotonically increase with the geomagnetic field fluctuations and ionospheric disturbances. These results indicate that the interferences in communication and navigation during space weather events may be the most probable reason accounting for the increased flight delays. The above analyses expand the traditional field of space weather research and could also provide us with brand new views for improving the flight delay predications.

Characteristics of flight delays during solar flares.

Solar flares are one of the severest solar activities that have important effects on near-Earth space. Previous studies have shown that flight arrival delays increase as a result of solar flares, but the intrinsic mechanism behind this relationship is still unknown. In this study, we conducted a comprehensive analysis of flight departure delays during 57 solar X-ray events by using a huge amount of flight data (~ 5 × 106 records) gathered over a 5-year period. It is found that the average flight departure delay time during solar X-ray events increased by 20.68% (7.67 min) compared to quiet periods. Our analysis also revealed apparent time and latitude dependencies, with flight delays being more serious on the dayside than on the nightside and longer (shorter) delays tending to occur in lower (higher) latitude airports during solar X-ray events. Furthermore, our results suggest that the intensity of solar flares (soft X-ray flux) and the Solar Zenith Angle directly modulate flight departure delay time and delay rate. These results indicate that communication interferences caused by solar flares directly affect flight departure delays. This work expands our conventional understanding of the impacts of solar flares on human society and provides new insights for preventing or coping with flight delays.

Spectral phase transfer to ultrashort UV pulses through four-wave mixing.

Transfer of spectral phase from near infrared ultrashort pulses to deep ultraviolet (UV) sub-30-fs pulses through four-wave mixing process is demonstrated. Micro joule UV pulses at 237 nm were generated by nonlinear mixing of second harmonic pulses of Ti:sapphire laser output and near infrared pulses from a noncollinear optical parametric amplifier. Chirp of the near infrared pulse was transferred to the UV pulse with the opposite sign. A positively chirped near infrared pulse was used for generating a negatively chirped UV pulse, which was compressed down to 25 fs by a magnesium fluoride window.

Energetic electrons associated with magnetic reconnection in the magnetic cloud boundary layer.

Here is reported in situ observation of energetic electrons (∼100-500 keV) associated with magnetic reconnection in the solar wind by the ACE and Wind spacecraft. The properties of this magnetic cloud driving reconnection and the associated energetic electron acceleration problem are discussed. Further analyses indicate that the electric field acceleration and Fermi-type mechanism are two fundamental elements in the electron acceleration processes and the trapping effect of the specific magnetic field configuration maintains the acceleration status that increases the totally gained energy.

Lactoferrin-derived peptides and Lactoferricin chimera inhibit virulence factor production and biofilm formation in Pseudomonas aeruginosa.

AIMS: To investigate the bactericidal activity of lactoferrin-derived peptides and a new LF-derived peptides chimera (LFchimera) against P. aeruginosa and the influence on virulence factors of P. aeruginosa. METHODS AND RESULTS: Lactoferricin (LFcin) and lactoferrampin (LFampin) are highly bioactive peptides isolated from the N-terminal region of lactoferrin (LF) by pepsin digestion. In this study, we designed LFchimera containing LFcin amino acids 17-30 and LFampin amino acids 268-284. Pseudomonas aeruginosa cells were incubated in medium with peptides at different concentrations, and then the assays of viability, pyocyanin, elastase activity and biofilm formation of P. aeruginosa were performed. We found that the concentration-dependent antibactericidal activity and down-regulating pyocyanin, elastase and biofilm formation of LFchimera were significantly stronger than those of LF, LFcin, LFampin or LFcin plus LFampin. CONCLUSIONS: Our results indicated that LF, LFcin, LFampin and LFchimera were potential candidates to combat P. aeruginosa, and LFchimera was the most effective in them. SIGNIFICANCE AND IMPACT OF THE STUDY: The new LFchimera has better activity against P. aeruginosa than LF, LFcin and LFampin and may be a promising new compound for treatment of P. aeruginosa infection.

Long non-coding RNA LINC00346 regulates proliferation and apoptosis by targeting miR-128-3p/SZRD1 axis in glioma.

OBJECTIVE: Long non-coding RNAs (lncRNAs) participate in multiple processes of malignant tumors, including glioma. In this study, we aimed to explore the effect of LINC00346 on glioma and its underlying mechanism. MATERIALS AND METHODS: The Cancer Genome Atlas (TCGA) and the Chinese Glioma Genome Atlas (CGGA) databases were used to analyze the expression patterns and survival risk of LINC00346, miR-128-3p and SUZ RNA binding domain containing 1 (SZRD1) in glioma tissues. The binding sites were predicted by bioinformatic databases, and then, validated by Dual-Luciferase assay and RNA immunoprecipitation (RIP). qRT-PCR and Western blot were performed to evaluate the gene expression levels. CellTiter-Glo® and colony formation assays were used to detect the proliferation of glioma cells. Flow cytometric analysis was used to evaluate the apoptosis of glioma cells. The xenograft models were established to investigate the impact of LINC00346 on tumor growth in vivo. RESULTS: We found that both LINC00346 and SZRD1 expression were negatively related to the poor overall survival rate in glioma patients. However, miR-128-3p showed the opposite effect of survival outcomes. LINC00346 knockdown remarkably restrained cell proliferation both in vitro and in vivo, as well as inducing apoptosis by acting as a molecular sponge of miR-128-3p. Moreover, miR-128-3p bound to SZRD1 3'-UTR in a sequence-specific manner. In addition, LINC00346 knockdown significantly inhibited the expression of SZRD1 and the inhibition could be reversed by miR-128-3p mimics. Furthermore, cell proliferation and apoptosis affected by LINC00346 were partially rescued by modulating miR-128-3p or SZRD1 expression. CONCLUSIONS: LINC00346/miR-128-3p/SZRD1 axis played a crucial role in modulating the malignant progression of glioma, which may serve as a prognostic indicator and a probable therapeutic target for glioma.

Identification of vaccine candidates against serogroup B meningococcus by whole-genome sequencing.

Neisseria meningitidis is a major cause of bacterial septicemia and meningitis. Sequence variation of surface-exposed proteins and cross-reactivity of the serogroup B capsular polysaccharide with human tissues have hampered efforts to develop a successful vaccine. To overcome these obstacles, the entire genome sequence of a virulent serogroup B strain (MC58) was used to identify vaccine candidates. A total of 350 candidate antigens were expressed in Escherichia coli, purified, and used to immunize mice. The sera allowed the identification of proteins that are surface exposed, that are conserved in sequence across a range of strains, and that induce a bactericidal antibody response, a property known to correlate with vaccine efficacy in humans.

Nasal administration of cholera toxin B subunit-nerve growth factor improves the space learning and memory abilities in beta-amyloid protein(25-35)-induced amnesic mice.

Nerve growth factor (NGF) is a potential drug for Alzheimer's disease treatment, but delivering NGF to the brain is difficult. To increase the content of NGF in brain, we prepared cholera toxin B subunit (CB) -NGF by the improved sodium metaperiodate method and compared its pharmacodynamics with NGF. In vitro, CB-NGF, as well as NGF, could promote neurite outgrowth and increase choline acetyltransferase activities. But the time window of TrkA phosphorylation induced by CB-NGF and NGF was different. In vivo, nasal administration of CB-NGF could increase the stay time and partially improve abilities of space learning and memory in amnesic mice, and protected the cholinergic neurons in basal forebrain against Abeta(25-35). CB-NGF treatment has better curative effects than NGF in Alzheimer's disease model mice.

Effects of D-galactose on the expression of hippocampal peripheral-type benzodiazepine receptor and spatial memory performances in rats.

The changes in spatial memory performances and the binding of hippocampal peripheral-type benzodiazepine receptor (PBR) induced by D-galactose (D-gal) were investigated in rats. The animals were randomly divided into two groups: saline-treated group and D-gal-induced aging group. All rats received 56 days of injection followed by 5 days of behavioral tests. The D-gal-induced aging rats presented significant impairment in water maze performance, compared with that in the saline-treated rats. A significant decrease in [3H]PK11195 binding in the synaptosomes from hippocampus in the D-gal-induced aging rats was observed, compared to that in the saline-treated rats. Meanwhile, the Scatchard analysis revealed that there was a decrease in Bmax, with no significant change in KD. Further analysis demonstrated that water maze performance was closely related to the PK11195 binding in all rats. These results suggest that D-gal decreased the density of PBR in hippocampal synaptosomes, which may be attributable to the progressive pathogenesis of aging in rats.

A Systems Model for Ursodeoxycholic Acid Metabolism in Healthy and Patients With Primary Biliary Cirrhosis.

A systems model was developed to describe the metabolism and disposition of ursodeoxycholic acid (UDCA) and its conjugates in healthy subjects based on pharmacokinetic (PK) data from published studies in order to study the distribution of oral UDCA and potential interactions influencing therapeutic effects upon interruption of its enterohepatic recirculation. The base model was empirically adapted to patients with primary biliary cirrhosis (PBC) based on current understanding of disease pathophysiology and clinical measurements. Simulations were performed for patients with PBC under two competing hypotheses: one for inhibition of ileal absorption of both UDCA and conjugates and the other only of conjugates. The simulations predicted distinctly different bile acid distribution patterns in plasma and bile. The UDCA model adapted to patients with PBC provides a platform to investigate a complex therapeutic drug interaction among UDCA, UDCA conjugates, and inhibition of ileal bile acid transport in this rare disease population.

Analyses of the genomic methylation status of the human cyclin A1 promoter by a novel real-time PCR-based methodology.

The role of CpG methylation in the regulation of tissue-specific gene expression is highly controversial. Cyclin A1 is a tissue-specifically expressed gene that is strongly methylated in non-expressing tumor cell lines. We have established a novel real-time PCR method to quantitate genomic CpG methylation of the cyclin A1 promoter. Genomic DNA samples from different human organs were treated with bisulfite and amplified with methylation-specific primers and with primers amplifying methylated as well as non-methylated DNA. PCR product quantitation was obtained by using a fluorogenic probe labeled with FAM and TAMRA. These analyses demonstrated that the human cyclin A1 promoter was methylated in kidney, colon, spleen, testis, and small intestine, but not in brain, liver, pancreas, or heart. Expression of cyclin A1 was predominantly found in testis. Low level expression of cyclin A1 was present in spleen, prostate, leukocytes, colon, and thymus. Taken together, our data provide evidence that CpG methylation patterns of the human cyclin A1 promoter in human organs do not generally correlate with cyclin A1 gene expression in vivo.

Preferential release of newly synthesized [(3)H]GABA from striatal slices to preloaded [(3)H]GABA.

The release of [(3)H]GABA which is newly synthesized from [(3)H]l-glutamic acid (GLU) has been examined using striatal slices obtained from the rat brain. It was found that 8-10% of [(3)H]GLU transported was converted to [(3)H]GABA during the incubation of striatal slices in the presence of nipecotic acid (5 x 10(?5) M). Nipecotic acid was added to the medium in order to prevent possible reuptake of [(3)H]GABA released during its synthesis, and it was found to have no significant effect on the formation of [(3)H]GABA from [(3)H]GLU as well as on the uptake of [(3)H]GLU. The application of high potassium (60 mM) stimulation exhibited a significant enhancement of the release of this newly synthesized [(3)H]GABA in a Ca(2+) dependent manner. Kinetic analysis revealed that the evoked release of newly synthesized [(3)H]GABA was approximately two times greater than that of previously-loaded [(3)H]GABA, whereas no significant difference was observed in the spontaneous release. An immobilization stress in water failed to affect the release of newly synthesized [(3)H]GABA from striatal slices despite the occurrence of a significant enhancement of GABA formation in this structure. These results suggest that newly synthesized GABA may be preferentially released from its nerve terminals in response to the excitation of neurons at least in the striatum as compared with previously accumulated GABA.