[Predictive value of whole brain perfusion on admission for shunt-dependent hydrocephalus fllowing aneurysmal subarachnoid hemorrhage].

Objective: To explore the value of predicting shunt-dependent hydrocephalus (SDHC) in patients with aneurysmal subarachnoid hemorrhage (aSAH) based on whole brain CT perfusion(CTP) and clinical data within 24 hours at admission. Methods: The clinical and imaging data of aSAH patients who received interventional embolization in our hospital were retrospectively collected from March 2018 to August 2022. All patients underwent one-stop whole brain CT examination within 24 hours after symptom onset, and the qualitative and quantitative CTP parameters were obtained after post-processing. Follow-up was conducted once every 2 months by consulting electronic medical records or by telephone for 6 months. According to whether SDHC occurred or not, the patients were divided into SDHC group and non-SDHC group. The differences between the two groups were compared. Logistic regression model was used to analyze and determine the predictive factors of SDHC, and the SDHC predictive model was established. The effectiveness of the predictive model was evaluated by drawing the receiver operating characteristic (ROC) curve of the subjects. Results: A total of 414 patients were included, including 132 males and 282 females, aged (59±11) years. 17.6%(73/414) patients had SDHC. There were significant differences in the occurrence of acute hydrocephalus, the World Neurosurgical League Scale (WFNS), the Hunt-Hess scale, the modified Fisher score (mFS), and the qualitative and quantitative parameters of CTP between the two groups (both P<0.001). Multivariate logistic regression analysis showed that acute hydrocephalus (OR=8.621, 95%CI: 4.237-17.542),old age (OR=1.107, 95%CI: 1.068-1.148), high mFS and high Hunt-Hess classification (OR=3.740, 95%CI: 1.352-10.342) were the risk factors of SDHC in aSAH patients, and high mean cerebral blood flow (mCBF) (OR=0.931, 95%CI: 0.885-0.980) was a protective factor of SDHC.The area under ROC curve (AUC) of the prediction model constructed by these five variables was 0.923(95%CI: 0.89-0.95), with 84.5% sensitivity and 87.7% specificity. Conclusion: The mCBF and acute hydrocephalus, age, mFS and Hunt-Hess classification within 24 hours at admission can be used to predict SDHC for aSAH patients.

CT-based staging and prognosis of novel coronavirus (COVID-19) pneumonia: correlation with blood glucose levels.

OBJECTIVE: Based on the latest epidemic situation and field experience, this study aims to explore the correlation of computed tomography (CT) stages and blood glucose level in patients with novel coronavirus pneumonia (COVID-19). PATIENTS AND METHODS: The clinical data of first and multiple CT imaging re-examination and blood glucose levels from 62 confirmed cases of COVID-19 were collected for a retrospective analysis to determine the correlation between glucose level and CT-based staging. RESULTS: Of the 62 COVID-19 patients, 48 cases of early stage and 14 cases of advanced stage were found in the CT data of the first diagnosis. These 62 cases were currently under follow-up (17-32 days): 18 cases in early stage-resorption stage, 25 cases in early stage-advanced stage-resorption stage, 12 cases in advanced stage-resorption stage, 5 cases in early stage -advanced stage-severe stage-resorption stage, and 2 cases in advanced stage-severe stage-resorption stage. Among them, the CT of 14 patients with advanced stage at the first diagnosis showed multiple stage lesions (advanced stage + early stage) at the same time. Patients presented with statistically significant changes in blood glucose at early stage-resorption stage, early stage-advanced stage-resorption stage, advanced stage-resorption stage, and early stage-advanced stage-severe stage-resorption stage (p<0.05). However, no statistically significant alterations were observed in the glucose level of patients with advanced stage-severe stage-resorption stage (p>0.05). CONCLUSIONS: Alteration of blood glucose is positively correlated with CT-based staging of COVID-19. Blood glucose is of great value in clinical diagnosis of COVID-19 and in determining the stage and prognosis of this disease.

Irisin ameliorates bone loss in ovariectomized mice.

Purpose: This study aimed to evaluate the effects of irisin on bones of ovariectomized (OVX) mice, to explore a possible treatment for postmenopausal osteoporosis.Methods: The OVX mice were treated with intraperitoneal injections of recombinant irisin (r-irisin) or saline twice a week for 5 weeks. The trabecular bone structure of the femur, the bone strength of the tibia, and serum parameters were assessed.Results: Treatment with r-irisin prevented the trabecular bone loss of the OVX mice. The r-irisin-treated OVX mice exhibited a greater bone microarchitecture, with significantly increased bone mineral density, bone volume to tissue volume ratio, connection density, and trabecular number parameters compared to those of the saline-treated OVX mice. The improved bone microarchitecture induced an increased bone stiffness in r-irisin-treated OVX mice. Consistently, the OVX mice treated with r-irisin showed a significantly increased number of osteoblasts on the trabecular surface and a significantly decreased number of osteoclasts. The r-irisin-treated OVX mice also had a higher osteocalcin level and a lower tartrate-resistant acid phosphatase concentration in serum.Conclusion: Irisin increases osteoblasts and decreases the number of osteoclasts, which leads to the maintenance of bone mass and quality in OVX mice. Irisin likely preserves the bone microarchitecture via building a 'new balance'. Therefore, our study extended the understanding of the role of irisin in bone metabolism and revealed the possibility of therapeutic application of irisin for postmenopausal osteoporosis.

Effects of steam explosion pretreatment and Lactobacillus buchneri inoculation on fungal community of unensiled and ensiled total mixed ration containing wheat straw during air exposure.

AIM: To compare the effects of steam explosion and Lactobacillus buchneri inoculation on fungal community in ensiled total mixed ration (TMR) during aerobic exposure. METHODS AND RESULTS: The TMRs were prepared using wheat straw with or without steam explosion, sweet potato residue, lucerne hay, maize meal and soybean meal, and ensiled with or without L. buchneri inoculation. Fungal communities were detected by high-throughput sequencing. All ensiled TMRs were well ensiled and steam explosion has a major effect on improving aerobic stability. The fungal species, such as Xeromyces bisporus and Cryptococcus victoriae, that dominated in the TMR decreased after ensiling, with a concomitant increase in Candida humilis, Pichia kudriavzevii, Aspergillus flavus and Phanerochaete chrysosporium. Most mould species decreased, with C. humilis and P. kudriavzevii dominating during aerobic exposure. CONCLUSION: Steam explosion could improve the aerobic stability in ensiled TMR by inhibition of C. humilis. SIGNIFICANCE AND IMPACT OF THE STUDY: High-throughput sequencing used in this study provides insight into the fungal community in ensiled TMR during aerobic exposure, which could contribute towards elucidating the mechanism by which aerobic deterioration develops.

Association between cystatin C and heart failure with preserved ejection fraction in elderly Chinese patients.

BACKGROUND: Approximately 50 % of patients with heart failure have a preserved ejection fraction (HFpEF). Cystatin C has been reported to be associated with cardiovascular events. This study was carried out to investigate whether cystatin C is associated with cardiac function and cardiac diastolic properties in elderly Chinese HFpEF patients. MATERIAL AND METHODS: A cross-sectional study of 381 elderly Chinese HFpEF patients (81 women, average age 82 ± 6 years) was conducted. Serum concentrations of cystatin C and the New York Heart Association (NYHA) classification were assessed and early (E) to late (A) transmitral flow velocity ratios (E/A ratio) were measured to assess cardiac diastolic properties. RESULTS: Cystatin C levels, N­terminal pro brain natriuretic peptide (NT-proBNP) levels and age were significantly correlated to the NYHA class (r = 0.605 P < 0.001, r = 0.333 P < 0.001 and r = 0.254 P < 0.001, respectively). Cystatin C levels, age and body mass index (BMI) were negatively correlated to the E/A ratio (r = -0.224 P = 0.005, r = -0.258 P = 0.001 and r = -0.258 P = 0.003, respectively). The patients with cystatin C concentrations below 1.3 mg/l had a higher E/A ratio compared to those with cystatin C concentrations higher than 1.3 mg/l. Cystatin C was also significantly associated with both the NYHA classification and the E/A ratio even after adjustment for the creatinine clearance rate (CCr). CONCLUSION: Both cystatin C and NT-proBNP were found to be correlated to the NYHA classification. Independent of renal function, higher serum concentrations of cystatin C were associated with a worse NYHA classification and abnormal cardiac diastolic properties in elderly Chinese HFpEF patients.

Association of HLA-DQB1*03:03 with pityriasis rosea in Chinese patients.

BACKGROUND: The association of human leucocyte antigen (HLA) with a variety of diseases has been described, especially with various autoimmune diseases. However, there are few studies on the association between HLA and pityriasis rosea (PR). AIM: To investigate the relevance of HLA II alleles with the development of PR. METHODS: Typing for HLA-DRB1, HLA-DQA1 and HLA-DQB1 typing was performed in 55 patients with PR and 90 healthy controls (HCs), using sequence-based typing (SBT) and PCR with sequence-specific primers (PCR-SSP), respectively. RESULTS: We found that the frequency of HLA-DQB1*03:03 was significantly higher in the PR compared with the HC group [P = 0.001; relative risk (RR) = 2.24; 95% CI 1.38-3.6], while suggestive evidence for a protective effect of HLA-DQB1*06:06 was observed in the study cohort (P < 0.02; RR = 0.40; 95% CI 0.17-0.90). CONCLUSIONS: The HLA-DQB1*03:03 allele may be a susceptible factor in patients with PR. In addition, the association of HLA-DQB1*03:03 with PR suggests participation of immunity in the pathogenesis of PR.

[Gene Analysis for the Sudden Death of Hypertrophic Cardiomyopathy by Whole Exome Sequencing.]

OBJECTIVES: To analyze the related pathogenicity gene mutations in a sudden death of hypertrophic cardiomyopathy （HCM） on whole exome level. METHODS: Whole exome sequencing （WES） was been performed on a sudden death case sample with pathological features of HCM by Illumina® Hiseq 2500 platform. Using hg19 as the reference sequences, the sequencing data were analyzed. Suspicious single nucleotide variants （SNV） were screened, and the conservatism and function were analyzed by the software such as PhyloP, PolyPhen-2, SIFT, etc. RESULTS: After screening, a heterozygous mutation C719R was finally identified in the gene MYBPC3 of this case. CONCLUSIONS: The molecular anatomy on whole exome level by second generation sequencing technology can help to define the molecular mechanism of HCM and provide a new mothed and thought for analysis of death cause.

The value of Gd-BOPTA- enhanced MRIs and DWI in the diagnosis of intrahepatic mass-forming cholangiocarcinoma.

The aim of this study is to explore the value of unenhanced magnetic resonance imaging (MRI), gadobenate dimeglumine injection (Gd-BOPTA)-enhanced MRI and diffusion-weighted imaging (DWI) in the diagnosis of intrahepatic mass-forming cholangiocarcinoma (IMCC). Totally 59 IMCC patients who underwent Gd-BOPTA-enhanced MRIs were recruited. The time-signal intensity curves and lesion periphery enhancement rates of the IMCC and liver parenchyma was drawn using apparent diffusion coefficient (ADC) values. The Gd-BOPTA-enhanced MRI showed that the peripheries of 30 lesions in the arterial phase exhibited irregular ring enhancement. However, lesions in the portal and delayed phases (which were gradually filled with a contrast agent), presented a patchy or latticed enhancement. Twenty-two lesions in the arterial and delayed phases exhibited uneven mild/moderate patchy enhancements with a progressive and centripetal lesion. Five lesions emerged from the arterial phase without any significant enhancement and had only gradual enhancement during the delayed phase. The remaining 2 lesions had a decreased mild enhancement, presented comparatively high signals and the lesion center had visible small spotted low signals. The DWI signals displayed a slightly high or high unevenness. Some lesion peripheries had a high signal but lesion centers displayed a relatively low or slightly low signal and irregular patches. There were significant differences between the ADC values of the lesion edge, lesion center and liver parenchyma. The IMCC detection rates of the Gd-BOPTA-enhanced MRI and DWI were higher than those of the unenhanced MRI. Our study demonstrated that both the Gd-BOPTA-enhanced MRI and DWI had higher accuracies rates than an unenhanced MRI. Furthermore, the hepatobiliary phase of IMCC plays an important role in the diagnosis and identification of IMCC constituents.

Dynamics of microbial community during ensiling direct-cut alfalfa with and without LAB inoculant and sugar.

AIM: To gain deeper insights into the clostridial community dynamics and chemical transformations during the ensiling of alfalfa. METHODS AND RESULTS: Direct-cut alfalfa silage (with the dry matter content of 240 g kg-1 ) was prepared with or without the addition of a lactic acid bacterial inoculant and sucrose. Silages were sampled at 0, 3, 7, 14, 28 and 56 days after ensiling and their bacterial community was determined using high-throughput sequencing with a special focus on the clostridial community. A clostridial fermentation occurred in the control silage, with high contents of acetic acid, butyric acid and ammonia nitrogen and Clostridia counts; while the inoculated silage was well preserved, with low pH and high lactic acid content. Lactic acid bacteria dominated the bacterial community during the ensiling process. In the control silage, Weissella confusa, Lactobacillus brevis, Enterococcus mundtii and Pediococcus acidilactici were identified at the beginning of the fermentation. Thereafter, W. confusa, Lactobacillus helsingborgensis and Bifidobacterium asteroides appeared and quickly prevailed. In the inoculated silage, Lactobacillus plantarum dominated the whole ensiling process. The genus Clostridium dominated the clostridial community, and was depressed with the inoculated treatment. Clostridium perfringens, Garciella sp. and Clostridium baratii were the main initiators of the clostridial fermentation of the control silage, while Clostridium tyrobutyricum became the most abundant Clostridia with prolonged ensiling. Overall in the inoculated silage, little changes in the clostridial community were observed throughout the ensiling period. Treating alfalfa silage with a homolactic acid-based bacterial inoculant prevented a clostridial fermentation resulting in more efficient fermentation. CONCLUSION: Distinct changes in the bacterial community with a special focus on the clostridial community were associated with the development of the clostridial fermentation during the ensiling of alfalfa. SIGNIFICANCE AND IMPACT OF THE STUDY: High-throughput sequencing based on a novel Clostridia-specific primer set proved a potentially useful tool to study the clostridial community dynamics, and could aid to elucidate the mechanism by which the clostridial fermentation develops during the ensiling of alfalfa.

Protein expression in dairy cows with and without subclinical hypocalcaemia.

AIM: To determine differences in plasma proteomic profiles between healthy cows and those with subclinical hypocalcaemia within 12 hours after calving, and thereby explore the underlying biological mechanism of subclinical hypocalcaemia in dairy cows. METHODS: Plasma samples were collected within 6 hours of calving from Holstein cows on a farm in Heilongjiang, China; 32 with subclinical hypocalcaemia (plasma calcium concentration 1.38-2.00 mmol/L and no clinical signs) and 59 control cows (plasma calcium concentration 2.10-2.8 mmol/L). Plasma samples were applied to weak cationic exchange protein chips for protein profiling by surface-enhanced laser desorption/ionisation time-of-flight mass spectrometry (SELDI-TOF-MS), and the data were analysed using the PBS-IIC system. The amplitude of peaks for the two groups were compared using the Wilcoxon sum-rank test, and the mass-to-charge ratio of the peaks that differed was used to identify peptide fragments using the Swiss-Prot protein database. RESULTS: Seven peaks were identified in the subclinical hypocalcaemia group that differed from those of the control group (p<0.001), that represented six unique proteins. Expression of serum albumin, fibrinogen alpha chain, amyloid beta A4 proteins and neurosecretory protein VGF were increased, and expression of apolipoprotein A-II and serum amyloid A proteins were decreased in the subclinical hypocalcaemic cows compared with control cows. CONCLUSION: Use of SELDI-TOF-MS technology can effectively identify differences in plasma protein expression patterns in cows with subclinical hypocalcaemia. Neurosecretory protein VGF and amyloid beta A4 protein might represent useful biomarkers for diagnosis of subclinical hypocalcaemia.

Aerobic Stability and Effects of Yeasts during Deterioration of Non-fermented and Fermented Total Mixed Ration with Different Moisture Levels.

The present experiment evaluated the influence of moisture level and anaerobic fermentation on aerobic stability of total mixed ration (TMR). The dynamic changes in chemical composition and microbial population that occur after air exposure were examined, and the species of yeast associated with the deterioration process were also identified in both non-fermented and fermented TMR to deepen the understanding of aerobic deterioration. The moisture levels of TMR in this experiment were adjusted to 400 g/kg (low moisture level, LML), 450 g/kg (medium moisture level, MML), and 500 g/kg (high moisture level, HML), and both non-fermented and 56-d-fermented TMR were subjected to air exposure to determine aerobic stability. Aerobic deterioration resulted in high losses of nutritional components and largely reduced dry matter digestibility. Non-fermented TMR deteriorated during 48 h of air exposure and the HML treatment was more aerobically unstable. On dry matter (DM) basis, yeast populations significantly increased from 10(7) to 10(10) cfu/g during air exposure, and Candida ethanolica was the predominant species during deterioration in non-fermented TMR. Fermented TMR exhibited considerable resistance to aerobic deterioration. Spoilage was only observed in the HML treatment and its yeast population increased dramatically to 10(9) cfu/g DM when air exposure progressed to 30 d. Zygosaccharomyces bailii was the sole yeast species isolated when spoilage occurred. These results confirmed that non-fermented and fermented TMR with a HML are more prone to spoilage, and fermented TMR has considerable resistance to aerobic deterioration. Yeasts can trigger aerobic deterioration in both non-fermented and fermented TMR. C. ethanolica may be involved in the spoilage of non-fermented TMR and the vigorous growth of Z. bailii can initiate aerobic deterioration in fermented TMR.

Regulation of N-acetyl cysteine on gut redox status and major microbiota in weaned piglets.

This study was conducted to explore the regulation of N-acetyl cysteine (NAC) on gut redox status and proliferation of selected microbiota in weaned piglets. A total of 150 newborn piglets from 15 litters were randomly divided by litter to the control group (normally suckling), the weaning group (fed the basal diet), and the NAC group (basal + NAC diet) with 5 litters per group. Activities of total antioxidant capacity (T-AOC), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and inhibition capacity of hydroxyl radical (IHR), and contents of malondialdehyde (MDA), H2O2, and NO in the ileum, colon, and cecum were analyzed to profile oxidative stress states. The real-time absolute quantitative PCR reaction was employed to quantify the amounts of total bacteria, Lactobacillus, Bifidobacterium, and Escherichia coli. The N-acetyl cysteine, as a universal antioxidant, was used to improve the redox status. Results showed that weaning stress resulted in the occurrence of gut oxidative stress and changes of gut microbiota (P < 0.05). Compared with the weaned piglets, the activities of ileal, colonic, and cecal T-AOC; ileal and colonic GSH-Px; cecal SOD; and colonic and cecal IHR were enhanced (P < 0.05), and the concentrations of ileal and cecal H2O2, ileal and colonic NO, and colonic MDA were reduced (P < 0.05) in the NAC-treated piglets. An increase (P < 0.05) in gut Lactobacillus and Bifidobacterium, accompanied with a decrease (P < 0.05) in Escherichia coli counts, was also observed in the NAC group. Bivariate correlation indicated that Lactobacillus and Bifidobacterium were positively correlated (P < 0.05) with the activities of T-AOC, GSH-Px, and SOD and inversely related (P < 0.05) to increased levels of H2O2, NO, OH, and MDA, and Escherichia coli showed a strong positive association (P < 0.05) with increased levels of free radicals and MDA and a negative association (P < 0.05) with the activities of antioxidant enzymes in intestines of weaned piglets. We concluded that NAC constructively regulated on the changes of the gut redox status and microbiota in piglets in response to weaning stress. The observed correlations implied that the NAC effects on the gut microbiota were confirmed, partly through an effect on oxidative stress in piglets, providing evidence that gut microbiota may be potentially improved by the modulation of the redox status by an antioxidant, which has relevance for gut health and function.

Characterization of Th1- and Th2-type immune response in human multidrug-resistant tuberculosis.

Multidrug-resistant tuberculosis (MDR-TB) has become a lethal global threat. Insights into the immune regulation of MDR-TB are urgently needed for the development of new treatments; however, the T cell response to an MDR-TB infection in human remains unclear. In the present study, the proportion of Th1 and Th2 cell subsets and the level of related T cell subset cytokines in peripheral blood were investigated. We detected that an MDR-TB infection resulted in suppressed Th1 and Th2 cell activation, which was more remarkable in patients with MDR-TB than that in drug-sensitive tuberculosis (DS-TB) sufferers when compared to healthy controls (HCs). In addition, MDR-TB infection down-regulated the expression of IFN-γ, IL-2, and IL-10, and up-regulated IL-4, IL-6, and TNF-α expression. Our data suggest that the disturbance between protective and pathogenic effects induced by the immunosuppression of Th1- and Th2-type responses is a substantial characteristic of MDR-TB infections.

MUC19 expression in human ocular surface and lacrimal gland and its alteration in Sjögren syndrome patients.

This study investigated the expression of MUC19, a newly discovered gel-forming mucin gene, in normal human lacrimal functional unit components and its alteration in Sjögren syndrome patients. Real-time PCR and immunohistochemistry were performed to determine the expression of MUC19 and MUC5AC in human cornea, conjunctiva, and lacrimal gland tissues. Conjunctival impression cytology specimens were collected from normal control subjects and Sjögren syndrome patients for Real-time PCR, PAS staining, and immunohistochemistry assays. In addition, conjunctiva biopsy specimens from both groups were examined for the expression differences of MUC19 and MUC5AC at both mRNA and protein level. The MUC19 mRNA was found to be present in cornea, conjunctiva and lacrimal gland tissues. The immunohistochemical staining of mucins showed that MUC19 was expressed in epithelial cells from corneal, conjunctival, and lacrimal gland tissues. In contrast, MUC5AC mRNA was only present in conjunctiva and lacrimal gland tissues, but not in cornea. Immunostaining demonstrates the co-staining of MUC19 and MUC5AC in conjunctival goblet cells. Consistent with the significant decrease of mucous secretion, both MUC19 and MUC5AC were decreased in conjunctiva of Sjögren syndrome patients compared to normal subjects. Considering the contribution of gel-forming mucins to the homeostasis of the ocular surface, the decreased expression of MUC19 and MUC5AC in Sjögren syndrome patients suggested that these mucins may be involved in the disruption of the ocular surface homeostasis in this disease.

Fermentation quality and nutritive value of a total mixed ration silage containing coffee grounds at ten or twenty percent of dry matter.

Six wethers were used in a replicated 3 x 3 Latin square to study the fermentation quality and nutritive value of total mixed ration (TMR) silages that included wet coffee grounds (WCG). The TMR were prepared using a commercial compound feed, timothy hay, alfalfa hay, dried beet pulp, and a vitamin-mineral supplement in a ratio of 36.5:30:20:12:1.5, respectively, on a DM basis, with timothy hay and alfalfa hay being replaced by WCG at 0, 10, or 20%. All TMR silages, irrespective of WCG addition, were well preserved, with a low pH and ammonia-N content and a high lactic acid content. Intakes by wethers of TMR silages containing 0 and 10% WCG were 96.6 and 94.8 g/kg of BW(0.75), and did not differ (P > 0.05). Intake of TMR silage containing 20% WCG was 76.8 g/kg of BW(0.75), which was equal to 80% of that of the TMR silage with no WCG (quadratic: P < 0.01). Increasing concentrations of WCG in the rations decreased the digestibility of DM, CP, ADF, NDF, and energy, and increased that of ether extract (P < 0.05). The TDN and DE contents of the TMR silages with 0 and 10% WCG were similar, but the TMR silage with 20% WCG was lower (P < 0.05). With progressive increases in WCG concentrations, N intake did not differ, but fecal and urinary N increased linearly (P < 0.001), and retained N decreased linearly (P < 0.001). This study demonstrated that the proportion of WCG to be incorporated into TMR silages should not exceed 10% of the DM.

The inhibited xanthophyll cycle is responsible for the increase in sensitivity to low temperature photoinhibition in rice leaves fed with glutathione.

Exposure of intact rice leaves to an irradiance of 1000 mumol m(-2) s(-1) at 6 degrees C for 2 h caused severe photoinhibition of Photosystem II. The rate and extent of photoinhbition were greatly exacerbated in leaves fed with 10 mM reduced glutathione (GSH) or 10 mM cysteine. Analyses of antioxidant enzyme activities as well as the application of protein synthesis inhibitors revealed that the increased sensitivity to photoinhibition following GSH feeding was not related to its effect on cellular antioxidant systems. On the other hand, feeding with GSH markedly suppressed the formation of zeaxanthin and antheraxanthin via the xanthophyll cycle and its associated nonradiative energy dissipation in leaves chilled in high light, suggesting that the stimulating effect of exogenous GSH on photoinhibition may be attributable to its action on the xanthophyll cycle. In vitro experiments using isolated thylakoids indicated that GSH is a weak inhibitor of violaxanthin deepoxidation. The possible implications of these results are discussed.