[A dose-response meta-analysis on the relationship between daily tea intake and cardiovascular mortality based on the GRADE system]

Objective: To explore the relationship between daily tea intake and cardiovascular disease (CVD) mortality. Methods: PubMed, EMbase, The Cochrane, Chinese Biomedical Literature Database, CNKI, and Wanfang Database were searched to collect research on tea intake and CVD mortality. The search period was from the establishment of the database to June 2020. Two researchers independently screened and extracted literature. The risk of bias was evaluated in the included studies, a dose-response meta-analysis was conducted, sensitivity analysis and publication bias analysis of the research results, and quality evaluation of the included literature and GRADE classification of the evidence body were performed. Results: A total of 21 cohort or case-control studies were included, including 1 304 978 subjects. Among them, 38 222 deaths from CVD were reported. The quality scores of the included studies were all ≥ 6 points. The dose-response meta-analysis showed that for every additional cup of tea intake per day, the mortality rate of CVD decreased by about 3% (95%CI 0.95-0.98, P<0.05), and there was a non-linear dose-response relationship (P<0.05). Compared with people who do not drink tea, people who drink 1 to 8 cups of tea a day have 8% lower CVD mortality (RR=0.92, 95%CI 0.89-0.95), 13% (RR=0.87, 95 %CI 0.84-0.91), 15% (RR=0.85, 95%CI 0.82-0.89), 15% (RR=0.85, 95%CI 0.81-0.89), 16% (RR=0.84, 95%CI 0.80-0.89), 16% (RR=0.84, 95%CI 0.81-0.88), 16% (RR=0.84, 95%CI 0.81-0.87), 16% (RR=0.84, 95%CI 0.80-0.88), respectively. The results of traditional meta-analysis showed that compared with people who do not drink tea, people who drink more than 1 cup of tea a day are associated with 14% lower CVD mortality rate (RR=0.86, 95%CI 0.81-0.91, I²=73.2%, P<0.05). The results of subgroup analysis showed that compared with the corresponding people who did not drink tea, men who drank more than 1 cup of tea a day reduced the CVD mortality rate by 24%, women by 14%, European and American populations by 12%, and Asian populations by 15%. The population who consumed green tea decreased CVD mortality by 15%, and the population of non-smokers decreased CVD mortality by 20% (all P<0.05). The population who consumed black tea decreased CVD mortality by 8%, and the smoking population who consumed black tea decreased CVD mortality by 3%, and the difference was not statistically significant (all P>0.05). The results of the bias analysis showed that Begg=0.42 and Egger=0.62, indicating that the distribution on both sides of the funnel chart is symmetrical, suggesting that there is no publication bias. The results of sensitivity analysis showed that the effect size of the outcome index did not change significantly after excluding any article, indicating that the results are robust and credible. The GRADE evaluation showed that the evidence grades of the outcome indicators were all low grade. Conclusions: Daily tea consumption is related to reduced CVD mortality. It is therefore recommended to drink an appropriate amount of tea daily.

A shrimp glycosylase protein, PmENGase, interacts with WSSV envelope protein VP41B and is involved in WSSV pathogenesis

Viral glycoproteins are expressed by many viruses, and during infection they usually play very important roles, such as receptor attachment or membrane fusion. The mature virion of the white spot syndrome virus (WSSV) is unusual in that it contains no glycosylated proteins, and there are currently no reports of any glycosylation mechanisms in the pathogenesis of this virus. In this study, we cloned a glycosylase, mannosyl-glycoprotein endo-β-N-acetylglucosaminidase (ENGase, EC 3.2.1.96), from Penaeus monodon and found that it was significantly up-regulated in WSSV-infected shrimp. A yeast two-hybrid assay showed that PmENGase interacted with both structural and non-structural proteins, and GST-pull down and co-immunoprecipitation (Co-IP) assays confirmed its interaction with the envelope protein VP41B. In the WSSV challenge tests, the cumulative mortality and viral copy number were significantly decreased in the PmEngase-silenced shrimp, from which we conclude that shrimp glycosylase interacts with WSSV in a way that benefits the virus. Lastly, we speculate that the deglycosylation activity of PmENGase might account for the absence of glycosylated proteins in the WSSV virion.

The intracellular signaling pathway of octopamine upregulating immune resistance functions in Penaeus monodon

Octopamine (OA), a biogenic monoamine, is known to mediate several immune responses. This study analyzed the effects of OA on immunological regulation in the tiger shrimp Penaeus monodon. The immune parameters including total haemocyte count, differential haemocyte count, phenoloxidase activity, respiratory bursts, superoxide dismutase activity, and phagocytic activity and clearance efficiency in response to the pathogen, Photobacterium damselae, were determined when shrimp were individually injected with saline or OA at 100 or 1000 pmol shrimp^-1. In addition, the intracellular second messengers in haemocyte such as Ca²⁺ and adenosine 3',5'-cyclic monophosphate (cAMP) were examined in shrimp receiving saline or OA at 1 or 10 nmol shrimp^-1. Results showed that all of the immune parameters significantly increased at 2-4 h in OA-injected shrimp except hyaline cells in 100 pmol shrimp^-1-injected shrimp at 4 h, but phenoloxidase activity per granulocyte significantly decreased at 2-4 h. However, these had returned to saline control levels after receiving OA for 8 h except differential haemocyte count and phenoloxidase activity per granulocyte for 16 h. An injection of OA also significantly increased the survival rate of shrimp challenged with Pho. damselae. Shrimp receiving OA at 1 and 10 nmol shrimp^-1 significantly increased the intracellular Ca²⁺ concentration ([Ca²⁺]i) at 30-60 min and 30 min, and cAMP concentration [cAMP]i) at 5-15 min and 15 min, respectively. However, [Ca²⁺]i at 50-60 min, and [cAMP]i at 30-60 min returned to saline control when the shrimp received OA at 10 nmol shrimp^-1, and at 1 and 10 nmol shrimp^-1, respectively. These results suggest that OA administration by injection at ≤1000 pmol shrimp^-1 mediates transient upregulation of immunity together with the increased resistance of P. monodon to Pho. damselae, which are modulated through intracellular Ca²⁺ and cAMP second messenger pathways.

L-3,4-Dihydroxyphenylalanine (l-DOPA) induces neuroendocrinological, physiological, and immunological regulation in white shrimp, Litopenaeus vannamei

L-3,4-Dihydroxyphenylalanine (l-DOPA) is a precursor for dopamine (DA) synthesis. Assessments were conducted to analyze the effects of l-DOPA on mediating regulation of neuroendocrinological, immunological, and physiological parameters in the shrimp, Litopenaeus vannamei when they were individually injected with 0.01 N HCl or l-DOPA at 0.5 or 1.0 μmol shrimp^-1 for 60, 120, and 240 min. For catecholamine synthesis evaluation, tyrosine hydroxylase (TH) and DA beta hydroxylase (DBH) activities, l-DOPA, DA, and norepinephrine (NE) levels in hemolymph were determined. The total hemocyte count (THC), differential hemocyte count (DHC), phenoloxidase (PO) activity, respiratory bursts (RBs), superoxide dismutase (SOD) activity, phagocytic activity, and clearance efficiency in response to the pathogen, Vibrio alginolyticus were assessed for immune responses, and plasma glucose and lactate levels were for physiological response. Results showed that the TH activity, THC, hyaline cells (HCs), and semigranular cells (SGCs) at 120 min, DA levels at 60-240 min, PO activity in hemocytes per 50 μL of hemolymph at 60-120 min, and PO activity per granulocyte (granular cells (GCs) + SGCs) at 60 min significantly increased, but TH activity, l-DOPA levels, GCs, SGCs, and respiratory bursts in hemocytes per 10 μL of hemolymph at 60 min, respiratory bursts per hemocyte and SOD activity at 120 min, phagocytic activity at 60-240 min, and the clearance efficiency at 60-120 min significantly decreased in shrimp injected with l-DOPA at 1.0 μmol shrimp^-1. In another experiment, 60 min after shrimp had received l-DOPA at 0.5 or 1.0 μmol shrimp^-1, they were challenged with an injection of V. alginolyticus at 2 × 10⁵ colony-forming units (cfu) shrimp^-1. The injection of l-DOPA at 1.0 μmol shrimp^-1 also significantly increased the cumulative mortality of shrimp by 16.7%, compared to the HCl-challenged control after 120 h. These results suggest that l-DOPA administration at 1.0 μmol shrimp^-1 can mediate the transient regulation of neuroendocrinological, immunological, and physiologic responses resulting in immunosuppression, which in turn promoted the susceptibility of L. vannamei to V. alginolyticus.

Silencing tyrosine hydroxylase retards depression of immunocompetence of Litopenaeus vannamei under hypothermal stress

Tyrosine hydroxylase (TH), the first and rate-limiting step in the synthesis of catecholamines, is required in catecholamine synthesis of the neuroendocrine regulatory network against stress in shrimp. The immunocompetence, catecholamine biosynthesis, and carbohydrate metabolites were evaluated in Litopenaeus vannamei received L. vannamei TH (LvTH) double-stranded (ds)RNA, diethyl pyrocarbonate-water, or non-targeted dsRNA for 3 days then transferred from 28 to 20 or 28 °C. The immunocompetence of LvTH-depleted shrimp held at 28 °C was promoted, and those were downregulated under hypothermal stress and revealed higher level than the other two dsRNA treatments. Meanwhile, the decrease of catecholamine biosynthesis was observed in LvTH-depleted shrimp held at 28 °C, and those were elevated under hypothermal stress and revealed lower levels, compared to two dsRNA treatments. The reduced carbohydrate metabolites was observed in LvTH-depleted shrimp held at 28 °C, and those were upregulated under hypothermal stress and showed lower levels than the other two dsRNA treatments. It was therefore concluded that LvTH-depleted shrimp revealed enhanced immunocompetence and reduced carbohydrate metabolites when exposed to a hypothermal stress condition, and in the meantime, even though catecholamine biosynthesis was downregulated, no significant difference was observed in DA or NE levels.

The known two types of transglutaminases regulate immune and stress responses in white shrimp, Litopenaeus vannamei

Transglutaminases (TGs) play critical roles in blood coagulation, immune responses, and other biochemical functions, which undergo post-translational remodeling such as acetylation, phosphorylation and fatty acylation. Two types of TG have been identified in white shrimp, Litopenaeus vannamei, and further investigation on their potential function was conducted by gene silencing in the present study. Total haemocyte count (THC), differential haemocyte count (DHC), phenoloxidase activity, respiratory bursts (release of superoxide anion), superoxide dismutase activity, transglutaminase (TG) activity, haemolymph clotting time, and phagocytic activity and clearance efficiency to the pathogen Vibrio alginolyticus were measured when shrimps were individually injected with diethyl pyrocarbonate-water (DEPC-H2O) or TG dsRNAs. In addition, haemolymph glucose and lactate, and haemocytes crustin, lysozyme, crustacean hyperglycemic hormone (CHH), transglutaminaseI (TGI), transglutaminaseII (TGII) and clotting protein (CP) mRNA expression were determined in the dsRNA injected shrimp under hypothermal stress. Results showed that TG activity, phagocytic activity and clearance efficiency were significantly decreased, but THC, hyaline cells (HCs) and haemolymph clotting time were significantly increased in the shrimp which received LvTGI dsRNA and LvTGI + LvTGII dsRNA after 3 days. However, respiratory burst per haemocyte was significantly decreased in only LvTGI + LvTGII silenced shrimp. In hypothermal stress studies, elevation of haemolymph glucose and lactate was observed in all treated groups, and were advanced in LvTGI and LvTGI + LvTGII silenced shrimp following exposure to 22 °C. LvCHH mRNA expression was significantly up-regulated, but crustin and lysozyme mRNA expressions were significantly down-regulated in LvTGI and LvTGI + LvTGII silenced shrimp; moreover, LvTGII was significantly increased, but LvTGI was significantly decreased in LvTGI silenced shrimp following exposure to 28 and 22 °C. Knockdown of LvTGI and LvTGI + LvTGII also significantly increased the mortality of L. vannamei challenged with the pathogen V. alginolyticus. The same consequences have been confirmed in LvTGII silenced shrimp in our previous study. These results indicate that LvTGI and LvTGII not only reveal a complementary effect in gene expression levels but also play a key function in the immune defence mechanism of shrimp, by regulating the haemolymph coagulation, immune parameters and immune related gene expression, and in the regulation of carbohydrate metabolism.

Effects of siRNA-mediated silencing of Sal-like 4 expression on proliferation and apoptosis of prostate cancer C4-2 cells

The aim of this study was to evaluate the effects of small interfering RNA (siRNA)-inhibited expression of the Sal-like 4 (SALL4) gene on the proliferation, colony formation, and apoptosis of prostate cancer C4-2 cells. C4-2 cells were cultured and divided into a si-SALL4 group, a negative control siRNA group, and a blank control group. SALL4 mRNA levels and protein expression were detected by real-time polymerase chain reaction and western blot, respectively. Changes in the cell proliferation and colony formation capacities were observed by using the MTS colorimetric method and colony formation assay, respectively. The influence of SALL4 on apoptosis was assessed with flow cytometry, and the expression of apoptosis-related proteins B-cell lymphoma 2 (Bcl-2) and bcl-like-protein 4 (Bax) were detected by western blot. The si-SALL4 group had significantly lower mRNA and protein levels of SALL4 as well as decreased proliferation and colony formation capacities than the negative control group (P < 0.05). There were significantly more apoptotic cells in the si-SALL4 group compared to the negative control (P < 0.05), and the expression of Bcl-2 and Bax decreased and increased, respectively, after treatment with si-SALL4. Silencing SALL4 expression by using siRNA technology inhibited the proliferation and colony formation of C4-2 cells, and promoted apoptosis likely mediated by Bcl-2 and Bax expression. These results provide experimental basis for further elucidating the role of SALL4 in prostate cancer cells.

Comparative proteomic analysis of Litopenaeus vannamei gills after vaccination with two WSSV structural proteins

White spot syndrome virus (WSSV) is one of the most devastating viral pathogens of cultured shrimp worldwide. Recently published papers show the ability of WSSV structural protein VP28 to vaccinate shrimp and raise protection against the virus. This study attempted to identify the joining proteins of the aforementioned shrimp quasi-immune response by proteomic analysis. The other envelope protein, VP36B, was used as the non-protective subunit vaccine control. Shrimp were intramuscularly injected with rVPs or PBS on day 1 and day 4 and then on day 7 their gill tissues were sampled. The two-dimensional electrophoresis (2-DE) patterns of gill proteins between vaccinated and PBS groups were compared and 20 differentially expressed proteins identified by mass spectrometry, some of which were validated in gill and hemocyte tissues using real-time quantitative RT-PCR. Many of identified proteins and their expression levels also linked with the shrimp response during WSSV infection. The list of up-regulated protein spots found exclusively in rVP28-vaccinated shrimp include calreticulin and heat shock protein 70 with chaperone properties, ubiquitin, and others. The two serine proteases, chymotrypsin and trypsin, were significantly increased in shrimp of both vaccinated groups compared to PBS controls. The information presented here should be useful for gaining insight into invertebrate immunity.

The novel white spot syndrome virus-induced gene, PmERP15, encodes an ER stress-responsive protein in black tiger shrimp, Penaeus monodon

By microarray screening, we identified a white spot syndrome virus (WSSV)-strongly induced novel gene in gills of Penaeus monodon. The gene, PmERP15, encodes a putative transmembrane protein of 15 kDa, which only showed some degree of similarity (54-59%) to several unknown insect proteins, but had no hits to shrimp proteins. RT-PCR showed that PmERP15 was highly expressed in the hemocytes, heart and lymphoid organs, and that WSSV-induced strong expression of PmERP15 was evident in all tissues examined. Western blot analysis likewise showed that WSSV strongly up-regulated PmERP15 protein levels. In WSSV-infected hemocytes, immunofluorescence staining showed that PmERP15 protein was colocalized with an ER enzyme, protein disulfide isomerase, and in Sf9 insect cells, PmERP15-EGFP fusion protein colocalized with ER -Tracker™ Red dye as well. GRP78, an ER stress marker, was found to be up-regulated in WSSV-infected P. monodon, and both PmERP15 and GRP78 were up-regulated in shrimp injected with ER stress inducers tunicamycin and dithiothreitol. Silencing experiments showed that although PmERP15 dsRNA-injected shrimp succumbed to WSSV infection more rapidly, the WSSV copy number had no significant changes. These results suggest that PmERP15 is an ER stress-induced, ER resident protein, and its induction in WSSV-infected shrimp is caused by the ER stress triggered by WSSV infection. Furthermore, although PmERP15 has no role in WSSV multiplication, its presence is essential for the survival of WSSV-infected shrimp.

The impact of LH, E2, and P level of HCG administration day on outcomes of in vitro fertilization in controlled ovarian hyperstimulation

OBJECTIVES

The objective of this study was to evaluate the impact of luteinizing hormone (LH), estradiol (E2) and progesterone (P) levels on the day of human chorionic gonadotropin (HCG) administration on outcomes of in vitro fertilization (IVF) in controlled ovarian hyperstimulation (COH).

STUDY DESIGN

In this retrospective study, 129 infertile women undergoing IVF/intracytoplasmic sperm injection (ICSI) treatments were included; these cycles were stratified according to LH levels of ≥ 1.12 IU/L or < 1.12 U/L and according to E2 levels of ≥ 1,005.89 pmol/L or < 1,005.89 pmol/L. The main outcome measure was the clinical pregnancy rate.

RESULTS

The clinical pregnancy rate was significantly higher in the group with LH ≥ 1.12 IU/L than in the group with LH < 1.12 U/L (43.28% vs. 30.65%, p < 0.05). The clinical pregnancy rate was also higher in the group with E2 ≥ 1,005.89 pmol/L than in the group with average E2 < 1,005.89 pmol/L (42.86% vs. 30.51%, p < 0.05). Among the LH, E2, and P levels on the day of HCG administration, LH level was the most important predictor of outcomes of IVF in COH. The present data showed an adverse effect of low serum LH level (LH < 1.12 IU/L) on the day of HCG administration on clinical pregnancy rate. E2 level can also predict the outcomes of IVF in COH.

CONCLUSIONS

Low serum LH level (LH < 1.12 IU/L) and low serum E2 level (average E2 < 1,005.89 pmol/L) on the day of HCG administration led to low clinical pregnancy rates, while the P level on the day of HCG administration may have had little effect on clinical pregnancy.

A combined compensation method for the output voltage of an insulated core transformer power supply

An insulated core transformer (ICT) power supply is an ideal high-voltage generator for irradiation accelerators with energy lower than 3 MeV. However, there is a significant problem that the structure of the segmented cores leads to an increase in the leakage flux and voltage differences between rectifier disks. A high level of consistency in the output of the disks helps to achieve a compact structure by improving the utilization of both the rectifier components and the insulation distances, and consequently increase the output voltage of the power supply. The output voltages of the disks which are far away from the primary coils need to be improved to reduce their inhomogeneity. In this study, by investigating and comparing the existing compensation methods, a new combined compensation method is proposed, which increases the turns on the secondary coils and employs parallel capacitors to improve the consistency of the disks, while covering the entire operating range of the power supply. This method turns out to be both feasible and effective during the development of an ICT power supply. The non-uniformity of the output voltages of the disks is less than 3.5% from no-load to full-load, and the power supply reaches an output specification of 350 kV/60 mA.

Spawning stress triggers WSSV replication in brooders via the activation of shrimp STAT

In the early days of shrimp aquaculture, wild-captured brooders usually spawned repeatedly once every 2-4days. However, since the first outbreaks of white spot disease (WSD) nearly 20years ago, captured female brooders often died soon after a single spawning. Although these deaths were clearly attributable to WSD, it has always been unclear how spawning stress could lead to an outbreak of the disease. Using real-time qPCR, we show here that while replication of the white spot syndrome virus (WSSV; the causative agent of WSD) is triggered by spawning, there was no such increase in the levels of another shrimp DNA virus, IHHNV (infectious hypodermal and hematopoietic necrosis virus). We also show that levels of activated STAT are increased in brooders during and after spawning, which is important because shrimp STAT is known to transactivate the expression of the WSSV immediate early gene ie1. Lastly, we used dsRNA silencing experiment to show that both WSSV ie1 gene expression and WSSV genome copy number were reduced significantly after shrimp STAT was knocked-down. This is the first report to demonstrate in vivo that shrimp STAT is important for WSSV replication and that spawning stress increases activated STAT, which in turn triggers WSSV replication in WSSV-infected brooders.

Feeding hermit crabs to shrimp broodstock increases their risk of WSSV infection

White spot syndrome virus (WSSV) is a serious shrimp pathogen that has spread globally to all major shrimp farming areas, causing enormous economic losses. Here we investigate the role of hermit crabs in transmitting WSSV to Penaeus monodon brooders used in hatcheries in Vietnam. WSSV-free brooders became PCR-positive for WSSV within 2 to 14 d, and the source of infection was traced to hermit crabs being used as live feed. Challenging hermit crabs with WSSV confirmed their susceptibility to infection, but they remained tolerant to disease even at virus loads equivalent to those causing acute disease in shrimp. As PCR screening also suggests that WSSV infection occurs commonly in hermit crab populations in both Vietnam and Taiwan, their use as live feed for shrimp brooders is not recommended.

Identification and cloning of a selenophosphate synthetase (SPS) from tiger shrimp, Penaeus monodon, and its transcription in relation to molt stages and following pathogen infection

Complementary (c)DNA encoding selenophosphate synthetase (SPS) messenger (m)RNA of the tiger shrimp Penaeus monodon, designated PmSPS, was obtained from the hepatopancreas by a reverse-transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE). The 1582-bp cDNA contained an open reading frame (ORF) of 1248 bp, a 103-bp 5'-untranslated region (UTR), and a 231-bp 3'-UTR, which contained a conserved selenocysteine insertion sequence (SECIS) element, a conventional polyadenylation signal, and a poly A tail. The molecular mass of the deduced amino acid (aa) sequence (416 aa) was 45.5 kDa with an estimated pI of 4.85. It contained a putative selenocysteine residue which was encoded by the unusual stop codon, (275)TGA(277), which formed at the active site with residues Sec(58) and Lys(61). A comparison of amino acid sequences showed that PmSPS was more closely related to invertebrate SPS1, such as those of Heliothis virescens and Drosophila melanogaster a and b. PmSPS cDNA was synthesized in all tested tissues, especially in the hepatopancreas. PmSPS in the hepatopancreas of shrimp significantly increased after an injection with either Photobacterium damsela or white spot syndrome virus (WSSV) in order to protect cells against damage from oxidation, and enhance the recycling of selenocysteine or selenium metabolism, indicating that PmSPS is involved in the disease-resistance response. The PmSPS expression by hemocytes significantly increased in stage C, and then gradually decreased until stage A, suggesting that the cloned PmSPS in hemocytes might play a role in viability by renewing hemocytes and antioxidative stress response for new exoskeleton synthesis during the molt cycle of shrimp.

Identification and cloning of a selenium-dependent glutathione peroxidase from tiger shrimp, Penaeus monodon, and its transcription following pathogen infection and related to the molt stages

Complementary (c)DNA encoding glutathione peroxidase (GPx) messenger (m)RNA of the tiger shrimp Penaeus monodon was obtained from haemocytes by a reverse-transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE) method. The 1321-bp cDNA contained an open reading frame (ORF) of 564bp, a 69-bp 5'-untranslated region (UTR), and a 688-bp 3'-UTR containing a poly A tail and a conserved selenocysteine insertion sequence (SECIS) element. The molecular mass of the deduced amino acid (aa) sequence (188 aa) was 21.05kDa long with an estimated pI of 7.68. It contains a putative selenocysteine residue which is encoded by the unusual stop codon, (190)TGA(192), and forms the active site with residues Glu(75) and Trp(143). Comparison of amino acid sequences showed that tiger shrimp GPx is more closely related to vertebrate GPx1, in accordance with those in Litopenaeus vannamei and Macrobrachium rosenbergii. GPx cDNA was synthesised in lymphoid organ, gills, heart, haemocytes, the hepatopancreas, muscles, and intestines. After injected with either Photobacterium damsela or white spot syndrome virus (WSSV), the respiratory bursts of shrimp significantly increased in order to kill the pathogen, and induced increases in the activities of superoxide dismutase and GPx, and regulation in the expression of cloned GPx mRNA to protect cells against damage from oxidation. The GPx expression significantly increased at stage D(0/1), and then gradually decreased until stage C suggesting that the cloned GPx might play a role in the molt regulation of shrimp.

Effects of the probiotic, Bacillus subtilis E20, on the survival, development, stress tolerance, and immune status of white shrimp, Litopenaeus vannamei larvae

In this study, the probiotic, Bacillus subtilis E20, isolated from the human health food, natto, was used for white shrimp, Litopenaeus vannamei, larvae breeding to improve the larval survival rate and development by adding probiotic to the rearing water at (control), 10(8), and 10(9) cfu L(-1) salt water once every 3 days during the 14 days of breeding experiment. Thereafter, stress tolerance and immune status of postlarvae were evaluated. Shrimp larval development was significantly accelerated after adding the probiotic to the larval rearing water at a level of 10(9) cfu L(-1). The survival rate of larvae was significantly higher in the treatment with 10(9) cfu L(-1) compared to the control and the treatment with 10(8) cfu L(-1) after all larvae had metamorphosed to postlarvae. Adding the probiotic to the shrimp larvae rearing water produced a weak inhibition of bacterial growth by an analysis of the total bacterial count and presumptive Vibrio count. For stress tests, no postlarvae died when they were reared in water in which the temperature was decreased from 30 to 2 degrees C at a rate of 0.1 degrees C min(-1). Postlarvae had significantly lower cumulate mortality in the treatments with 10(8) and 10(9) cfu L(-1) compared to the control when they were suddenly exposed to fresh water and 60 per thousand salt water. A significant decrease in the cumulative mortality of postlarvae treated with the probiotic at a level of 10(9) cfu L(-1) was recorded after the sudden transfer to 300 mg L(-1) nitrite-N compared to the control and treatment with 10(8) cfu L(-1). The analysis of immune-related gene expressions showed that the gene expression of prophenoloxidase I, prophenoloxidase II, and lysozyme of larvae were significantly increased after being reared in probiotic-containing water at the levels of 10(8) and 10(9) cfu L(-1). However, no significant difference in serine proteinase or glutathione peroxidase gene expressions was recorded in this study. It is therefore suggested that 10(9) cfu L(-1) of probiotic, B. subtilis E20 adding to rearing water for shrimp larva breeding.

Identification and cloning of a selenium dependent glutathione peroxidase from giant freshwater prawn, Macrobrachium rosenbergii

A selenium dependent glutathione peroxidase (Se-GPx) cDNA was cloned from haemocyte by a reverse-transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA (RACE). The 913 bp cDNA contained an open reading frame (ORF) of 558 bp encoded a deduced amino acid sequence of 186 amino acids. The prawn Se-GPx sequence contains a selenocysteine (Sec) residue which is encoded by the unusual stop codon, (115)TGA(117). According to the molecular modeling analysis, the active site Sec residue, located in the loop between beta3 and alpha2 in a pocket on the protein surface, and hydrogen bonded to Gln(73) and Trp(141). A GPx signature motif 2, (63)LAFPCNQF(70) and active site motif, (151)WNFEKF(156), two arginine (R) residues, R(89) and R(167) contribute to the electrostatic architecture that directs the glutathione donor substrate, and two putative N-glycosylation site, (75)NNT(77) and (107)NGS(109) were observed in the prawn Se-GPx sequence. In addition, the eukaryotic selenocysteine insertion sequence element is conserved in the 3'-UTR. Comparison of amino acid sequences showed that prawn Se-GPx is more closely related to vertebrate GPx 1. The prawn Se-GPx was synthesized in haemocyte, hepatopancreas, muscle, stomach, gill, intestine, eyestalk, heart, epidermis, lymph organ, ventral nerve cord, testis and ovary. The increase of respiratory burst in haemocyte was observed in pathogen, Debaryomyces hansenii-injected prawn in order to kill the pathogen, and the up-regulation in SOD and GPx acitivity, and prawn Se-GPx mRNA transcription were involved with the protection against damage from oxidation.

Identification of the small heat shock protein, HSP21, of shrimp Penaeus monodon and the gene expression of HSP21 is inactivated after white spot syndrome virus (WSSV) infection

The white spot syndrome virus (WSSV) is the causative agent of a severe disease in cultivated shrimp. The virus causes high mortality and leads to heavy stress on shrimps. In response to a variety of stresses, living organisms express particular sets of genes such as HSPs. In this study, a HSP21 gene, categorized into the small heat shock protein (smHSP) family, of shrimp Penaeus monodon was identified by annotating the EST databases established from WSSV-infected and WSSV-uninfected shrimp. The shrimp HSP21 gene was 555 bp in length. The thermal aggregation assay showed that the HSP21 had chaperone activity. The result of real-time PCR indicated that HSP21 was constitutive and inducible and was highly expressed in almost all organs such as the epithelium, gill, stomach, midgut, lymphoid organ, hepatopancreas, nervous tissue and heart, but less expressed in haemolymph. However, HSP21 gene showed down-regulation after WSSV infection. It suggests that gene regulation of HSP21 was seriously affected by WSSV.

Cloning and molecular characterization of heat shock cognate 70 from tiger shrimp (Penaeus monodon)

We cloned the complementary deoxyribonucleic acid (cDNA) of the heat shock cognate 70 (hsc70) gene of tiger shrimp (Penaeus monodon). It was 2207 bp long and included a 1959-bp coding region, a 40-bp flanking region at the 5' end, and a 208-bp flanking region at the 3' end. The deduced, 652-amino acid sequence had a molecular mass of 71 481 Da and an estimated isoelectric point (pI) of 5.2. Based on phylogenetic analysis, the gene is clustered with the hsc70 proteins of invertebrates and vertebrates. In native gel electrophoresis, recombinant P. monodon hsc70 expressed in an Escherichia coli system is tightly associated with carboxymethylated alpha-lactalbumin (CMLA), which indicates that hsc70 probably functions as a chaperone. In an in vitro adenosine triphosphatase assay, recombinant hsc70 hydrolyzed adenosine triphosphate to adenosine-5'-diphosphate and increased hydrolysis activity by binding to unfolded peptide, CMLA. In situ hybridization using an antisense riboprobe revealed that the hsc70 gene was active in most tissues of unstressed shrimp. The expression of hsc70 messenger ribonucleic acid (mRNA) in hemocytes increased 2- to 3-fold at the first hour after shrimp experienced heat shock and 0.5-hour recovery. Hsc70 mRNA decreased gradually to the background level. Cloning and characterizing the P. monodon hsc70 gene is the first, crucial step in studying the relationship of heat shock proteins with the stress or immune responses of shrimp.

White spot syndrome virus (WSSV) PCR-positive Artemia cysts yield PCR-negative nauplii that fail to transmit WSSV when fed to shrimp postlarvae

Positive results were obtained with nested white spot syndrome virus (WSSV) diagnostic PCR performed on 5 commercial brands of dry-packed Artemia cysts using several WSSV genomic sequence-specific primers. In 2 brands, PCR and nucleotide sequence analysis found C-->T and C-->G point mutations in the pms 146 WSSV amplicon, but in all 5 brands, the nucleotide sequences that were successfully amplified by the rrl, rr2 and tk-tmk gene-specific primer sets were identical to those of Penaeus monodon WSSV. However, despite the inarguable presence of WSSV or WSSV-like template DNA, we were unable to detect WSSV by PCR in hatched nauplii derived from PCR-positive cysts or in P. monodon postlarvae fed Artemia nauplii hatched from such cysts. Most simply, these results suggested that the cysts were externally contaminated with WSSV or WSSV-like template material that was removed during hatching and washing of the nauplii. Given the small sequence variations found, it may also have been a variety of WSSV non-infectious for P. monodon or Artemia and derived from other crustaceans or arthropods in the Artemia environment. However, we could not establish this conclusively and a small possibility remained that the PCR template in these tests was derived from WSSV template present internally in the cysts and derived from infected Artemia adults. However small, this possibility must be vigorously tested, given the impact that a positive outcome could have on the shrimp industry.

Performance of WSSV-infected and WSSV-negative Penaeus monodon postlarvae in culture ponds

In a survey of 27 Penaeus monodon culture ponds stocked with postlarvae (approximately PL10) at medium density (approximately 40 shrimp m(-2)), single-step nested white spot syndrome virus (WSSV) PCR was used to measure the WSSV infection rates in the shrimp populations within 1 mo after stocking. Seven ponds were initially WSSV-free, and the shrimp in 5 of these were harvested successfully. In the ponds (n = 6) where detection rates were higher than 50%, mass mortality occurred during the growth period, and none of these ponds was harvested successfully. In a subsequent study, P. monodon brooders were classified into 3 groups according to their WSSV infection status before and after spawning: brooders that were WSSV-positive before spawning were assigned to group A; spawners that became WSSV-positive only after spawning were assigned to group B; and group C consisted of brooders that were still WSSV-negative after spawning. WSSV screening showed that 75, 44 and 14%, respectively, of group A, B and C brooders produced nauplii that were WSSV-positive. Most (57%; 16/28) of the brooders in group A produced nauplii in which the WSSV prevalence was high (>50%). When a pond was stocked with high-prevalence nauplii from 1 of these group A brooders, an outbreak of white spot syndrome occurred within 3 wk and only approximately 20% of the initial population survived through to harvest (after 174 d). By contrast, 2 other ponds stocked with low-prevalence and WSSV-negative nauplii (derived respectively from 2 brooders in group B), both had much higher survival rates (70 to 80%) and yielded much larger (approximately 3x by weight) total harvests. We conclude that testing the nauplii is an effective and practical screening strategy for commercially cultured P. monodon.

Regional variations in the apparent diffusion coefficient and the intracellular distribution of water in rat brain during acute focal ischemia

BACKGROUND AND PURPOSE

The apparent diffusion coefficient of water (ADC) rapidly drops in ischemic tissue after cerebral artery occlusion. This acute drop is thought to be caused by the loss of extracellular fluid and the gain of intracellular fluid. To test the latter possibility, changes in ADC and the size of several cellular compartments were assessed in 3 regions of rat brain at the end of 90 minutes of focal cerebral ischemia.

METHODS

One middle cerebral artery was permanently occluded in 8 Sprague-Dawley rats; sham occlusions were performed in 2 other rats. ADC maps were generated 90 minutes later, and the brains were immediately perfusion fixed. Three regions of interest (ROIs) were defined on the basis of ADC range. Various neuronal, astrocytic, and capillary compartments in each ROI were quantified with light and electron microscopy.

RESULTS

At the end of 90 minutes of ischemia, mean ADC was normal in the cortex of sham-operated rats and the contralateral cortex of ischemic rats (ROI-a), 25% lower in the ipsilateral frontoparietal cortex (ROI-b), and 45% lower in the ischemic lateral caudoputamen (ROI-c). At this time, the frequency of swollen astrocytic cell bodies and volume of swollen dendrites and astrocytic processes in neuropil were ROI-a<ROI-b<ROI-c. In ROI-b and ROI-c, 40% and 60% of the neurons, respectively, were shrunken; the shrunken neurons were approximately 25% smaller in ROI-c than in ROI-b. In these areas, many capillary endothelial cells, pericytes, and perivascular foot processes were swollen.

CONCLUSIONS

The initial lowering of ADC during focal ischemia probably is the result of not only the acute loss of extracellular fluid and concomitant swelling of various cellular compartments but also concurrent neuronal shrinkage.

Chiral symmetry, quark mass, and scaling of the overlap fermions

The chiral symmetry relation and scaling of the overlap fermions are studied numerically on the quenched lattices at 3 couplings with about the same physical volume. We find that the generalized Gell-Mann-Oakes-Renner relation is satisfied to better than 1% down to the smallest quark mass at m(0)a = 0.006. We also obtain the quark mass from the PCAC relation and the pseudoscalar masses. The renormalization group invariant quark mass is shown to be fairly independent of scale. The pi and rho masses at a fixed m(pi)/m(rho) ratio indicate small O(a(2)) corrections. It is found that the critical slowing down sets in abruptly at a very small quark mass close to those of the physical u and d quarks.

[A preliminary analysis on a group of low molecular weight RNases in wheat and related species]

By employing RNase activity gel analysis, we detected a novel group of RNases in wheat and related species. The molecular weight of the RNases varied from 8-14 kDa, which was lower than that of most plant RNases characterized previously. The small RNases expressed abundantly in seedlings and differed in their optimal pH and ionic requirement in digesting RNA substrate. Several members of the small RNases were detected in dormant and germinating wheat seeds. During germination, the activity of two RNases did not change significantly whereas that of the other two RNases showed a gradual pattern of decrease and increase, respectively.

Secondary decline in apparent diffusion coefficient and neurological outcomes after a short period of focal brain ischemia in rats

This study was designed to characterize the initial and secondary changes of the apparent diffusion coefficient (ADC) of water with high temporal resolution measurements of ADC values and to correlate ADC changes with functional outcomes. Fourteen rats underwent 30 minutes of temporary middle cerebral artery occlusion (MCAO). Diffusion-, perfusion-, and T2-weighted imaging was performed during MCAO and every 30 minutes for a total of 12 hours after reperfusion (n = 6). Neurological outcomes were evaluated during MCAO, every 30 minutes for a total of 6 hours and at 24 hours after reperfusion (n = 8). The decreased cerebral blood flow during MCAO returned to normal after reperfusion and remained unchanged thereafter. The decreased ADC values during occlusion completely recovered at 1 hour after reperfusion. The renormalized ADC values started to decrease secondarily at 2.5 hours, accompanied by a delayed increase in T2 values. The ADC-defined secondary lesion grew over time and was 52% of the ADC-defined initial lesion at 12 hours. Histological evaluation demonstrated neuronal damage in the regions of secondary ADC decline. Complete resolution of neurological deficits was seen in 1 rat at 1 hour and in 6 rats between 2.5 and 6 hours after reperfusion; no secondary neurological deficits were observed at 24 hours. These data suggest that (1) a secondary ADC reduction occurs as early as 2.5 hours after reperfusion, evolves in a slow fashion, and is associated with neuronal injury; and (2) renormalization and secondary decline in ADC are not associated with neurological recovery and worsening, respectively.

Transient and permanent resolution of ischemic lesions on diffusion-weighted imaging after brief periods of focal ischemia in rats : correlation with histopathology

BACKGROUND AND PURPOSE

The early ischemic lesions demonstrated by diffusion-weighted imaging (DWI) are potentially reversible. The purposes of this study were to determine whether resolution of initial DWI lesions is transient or permanent after different brief periods of focal brain ischemia and to evaluate histological outcomes.

METHODS

Sixteen rats were subjected to 10 minutes (n=7) or 30 minutes (n=7) of temporary middle cerebral artery occlusion or sham operation (n=2). DWI, perfusion-weighted imaging (PWI), and T(2)-weighted imaging (T(2)WI) were performed during occlusion; immediately after reperfusion; and at 0.5, 1.0, 1.5, 12, 24, 48, and 72 hours after reperfusion. After the last MRI study, the brains were fixed, sectioned, stained with hematoxylin and eosin, and evaluated for neuronal necrosis.

RESULTS

No MRI or histological abnormalities were observed in the sham-operated rats. In both the 10-minute and 30-minute groups, the perfusion deficits and DWI hyperintensities that occurred during occlusion disappeared shortly after reperfusion. The DWI, PWI, and T(2)WI results remained normal thereafter in the 10-minute group, whereas secondary DWI hyperintensity and T(2)WI abnormalities developed at the 12-hour observation point in the 30-minute group. Histological examinations demonstrated neuronal necrosis in both groups, but the number of necrotic neurons was significantly higher in the 30-minute group (95+/-4%) than in the 10-minute group (17+/-10%, P<0.0001).

CONCLUSIONS

Transient or permanent resolution of initial DWI lesions depends on the duration of ischemia. Transient resolution of DWI lesions is associated with widespread neuronal necrosis; moreover, permanent resolution of DWI lesions does not necessarily indicate complete salvage of brain tissue from ischemic injury.

Studies on effective PCR screening strategies for white spot syndrome virus (WSSV) detection in Penaeus monodon brooders

We re-tested stored (frozen) DNA samples in 5 independent polymerase chain reaction (PCR) replicates and confirmed that equivocal test results from a previous study on white spot syndrome virus (WSSV) in brooders and their offspring arose because amounts of WSSV DNA in the test samples were near the sensitivity limits of the detection method. Since spawning stress may trigger WSSV replication, we also captured a fresh batch of 45 brooders for WSSV PCR testing before and after spawning. Replicates of their spawned egg batches were also WSSV PCR tested. For these 45 brooders, WSSV prevalence before spawning was 67% (15/45 1-step PCR positive, 15/45 2-step PCR positive and 15/45 2-step PCR negative). Only 27 (60%) spawned successfully. Of the successful spawners, 56% were WSSV PCR positive before spawning and 74% after. Brooders (15) that were heavily infected (i.e. 1-step PCR positive) when captured mostly died within 1 to 4 d, but 3 (20%) did manage to spawn. All their egg batch sub-samples were 1-step PCR positive and many failed to hatch. The remaining 30 shrimp were divided into a lightly infected group (21) and a 2-step PCR negative group (9) based on replicate PCR tests. The spawning rates for these 2 groups were high (81 and 78%, respectively). None of the negative spawners (7) became WSSV positive after spawning and none gave egg samples positive for WSSV. In the lightly infected group (21), 6 brooders were 2-step WSSV PCR negative and 15 were 2-step WSSV PCR positive upon capture. However, all of them were WSSV PCR positive in replicate tests and after spawning or death. Four died without spawning. The remaining 17 spawned but only 2 gave egg samples PCR negative for WSSV. The other 15 gave PCR positive egg samples, but they could be divided into 2 spawner groups: those (7) that became heavily infected (i.e. 1-step PCR positive) after spawning and those (8) that remained lightly infected (i.e. became or remained 2-step PCR positive only). Of the brooders that became heavily infected after spawning, almost all egg sample replicates (91 %) tested 2-step PCR positive. One brooder even gave heavily infected (i.e. 1-step PCR positive) egg samples. For the brooders that remained lightly infected after spawning, only 27% of the egg sample replicates were 2-step PCR positive. Based on these results, we recommend that to avoid false negatives in WSSV PCR brooder tests screening tests should be delayed until after spawning. We also recommend, with our PCR detection system, discarding all egg batches from brooders that are 1-step PCR positive after spawning. On the other hand, it may be possible with appropriate monitoring to use eggs from 2-step PCR positive brooders for production of WSSV-free or lightly infected postlarvae. These may be used to stock shrimp ponds under low-stress rearing conditions.

Reversal of acute apparent diffusion coefficient abnormalities and delayed neuronal death following transient focal cerebral ischemia in rats

Twenty-two rats were subjected to 8, 15, 30, or 60 minutes of temporary middle cerebral artery occlusion (n = 5 per group) or sham occlusion (n = 2) in the magnetic resonance imaging unit. Diffusion-, perfusion-, and T2-weighted imaging were acquired before and during occlusion, and after reperfusion. A coregistration method was used to correlate the acute changes of the average apparent diffusion coefficient (ADCav) with the histology after 72 hours at the same topographic sites. The initially reduced ADCav values recovered completely in both the lateral caudoputamen and upper frontoparietal cortex in the 8-, 15-, and 30-minute groups, partially in the cortex, and not at all in the caudoputamen in the 60-minute group. The histology showed that the caudoputamen was either normal or had mild neuronal injury in the 8-minute group and invariably had some degree of neuronal death in the 15-, 30-, and 60-minute groups, whereas the cortex was either normal or had varying degrees of neuronal injury in all groups. No histological abnormalities were seen in the sham-operated rats. Our data suggest that acute ADCav reversal does not always predict tissue recovery from ischemic injury and that temporary focal ischemia for even 8-minute duration can cause delayed neuronal death that is more severe in the caudoputamen where the initial ADCav decline was greater than in the cortex.

Incomplete infarct and delayed neuronal death after transient middle cerebral artery occlusion in rats

BACKGROUND AND PURPOSE

The clinical syndrome of transient ischemic attacks is accompanied in a significant percentage of patients by brain lesions or neuroimaging abnormalities whose structural counterparts have not been defined. The objective of this study was to analyze, in an experimental model of short-term (< 25 minutes) focal ischemia and long-term (< or = 28 days) reperfusion, the extent and nature of the structural abnormalities affecting neurons and glia located within the territory of the transiently occluded artery.

METHODS

Adult Wistar rats (n = 121) had the origin of one middle cerebral artery (MCA) occluded with a nylon monofilament for periods of 10 to 25 minutes. Experiments of transient MCA occlusion were terminated at variable periods ranging from 1 day to 4 weeks. Control experiments consisted of (1) MCA occlusion without reperfusion (n = 7) lasting 7 to 14 days and (2) sham operations (n = 2) followed by 1- to 4-day survival. After in situ fixation, brain specimens were serially sectioned and subjected to detailed morphometric evaluations utilizing light and electron microscopes. The statistical method used to evaluate the results was based on ANOVA followed by Bonferroni's corrected t test and Student's t test comparisons.

RESULTS

Brain lesions were not detectable in the sham-operated controls. All brains with permanent MCA occlusion (7 to 14 days) had large infarctions with abundant macrophage infiltration and early cavitation. Forty-five (37%) of the experiments involving transient MCA occlusion had no detectable brain lesions after 4 weeks. Selective neuronal necrosis was found in 76 of 121 rats (63%) with transient MCA occlusion. Neuronal necrosis always involved the striatum, and in 29% of the brains with ischemic injury, necrosis also included a short segment of the cortex. In the striatum, the length of the arterial occlusion was the main determinant of the number of necrotic neurons (20 minutes [22.6 +/- 19] is worse than 10 minutes [4.9 +/- 7]) (P < .0001). In the cortex, the length of reperfusion determined the number of necrotic neurons appearing in layer 3. Experiments with reperfusion of 4 to 7 days' duration yielded more necrotic neurons per microscopic field (2.02 +/- 3) than those lasting fewer days (0.04 +/- 0.1) (P < .05). The histological features of these lesions underwent continuous change until the end of the fourth week, at which time necrotic neurons were still visible both in the striatum and in the cortex.

CONCLUSIONS

Arterial occlusions of short duration (< 25 minutes) produced, in 76 of 121 experiments (63%), brain lesions characterized by selective neuronal necrosis and various glial responses (or incomplete infarction). This lesion is entirely different from the pannecrosis/cavitation typical of an infarction that appears 3 to 4 days after a prolonged arterial occlusion. Delayed neuronal necrosis, secondary to a transient arterial occlusion or increasing numbers of necrotic neurons in experiments with variable periods of reperfusion, was a response observed only at a predictable segment of the frontoparietal cortex.

DNA scission after focal brain ischemia. Temporal differences in two species

BACKGROUND AND PURPOSE

Species- and model-dependent differences in cell response to focal brain ischemia may underlie differences in adhesion receptor expression. The aim of this study was to quantitatively evaluate the spatial and temporal distribution of dUTP incorporation into damaged DNA, as an indicator of ischemic injury, in the corpus striatum.

METHODS

Cerebral ischemia was produced in 16 nonhuman primates and 19 rats by occluding the middle cerebral artery (MCA:O) with reperfusion for various periods. In situ dUTP was incorporated into cells with DNA damage by terminal deoxynucleotidyl transferase (TdT), DNA polymerase I, or the Klenow fragment of DNA polymerase. Dual immunolabeling experiments with immunoprobes against neuronal, vascular, or glial marker proteins were performed.

RESULTS

Significant topographical differences in dUTP between the two species were seen. In both models the TdT and polymerase I regions changed characteristically during focal ischemia. The number and density of dUTP-labeled cells increased with time from MCA:O and were dramatically different between the species (2P < .001). By 2 hours of ischemia, the density of dUTP label was 48.8 +/- 10.3 cells/mm2 in the primate and 2.4 +/- 0.8 cells/mm2 in the rat (2P < .05), but these values became nearly identical by 24 hours of reperfusion. In the primate, 80.0 +/- 6.6% of labeled cells displayed microtubule-associated protein-2 antigen (at 2-hour MCA:O), while 1.8 +/- 0.5% were associated with microvessels at 24 hours of reperfusion.

CONCLUSIONS

In situ detection of DNA damage, accomplished by three methods, reveals distinct temporal, topographical, and density differences in ischemic injury to cells in the primate and the rat corpus striatum as a result of MCA:O.

Severe transient hypoglycemia causes reversible change in the apparent diffusion coefficient of water

BACKGROUND AND PURPOSE

The aim of this study was to determine the effects of temporary severe hypoglycemia on the apparent diffusion coefficient (ADC) acquired by diffusion-weighted MRI of brain water with the use of serial multislice ADC mapping in rats. Severe hypoglycemia reduces the extracellular space volume, as does ischemia. Demonstrating a reduction of ADC with hypoglycemia should increase our understanding of the mechanisms underlying ADC changes in ischemia and other conditions.

METHODS

Fasted rats were given regular insulin (15 IU/kg IP). Rats were subjected to 15 minutes (n = 5) and 50 minutes (n = 5) of temporary severe hypoglycemia, causing a transiently isoelectric electroencephalogram (EEG). ADC mapping was performed every 30 seconds beginning at the onset of isoelectricity for 8.5 minutes. ADC maps were also obtained later during the isoelectric EEG period and 10, 20, 30, and 40 minutes after glucose infusion. Control images were obtained from a separate group of animals suffering cardiac arrest (n = 5).

RESULTS

Abnormal ADC values were not observed before the onset of cerebral isoelectricity, except for isolated areas in the cortex and periventricular regions. Cortical ADC values globally declined at the onset of EEG isoelectricity. The ADC decline spread to subcortical regions within a few minutes. During the isoelectric period, significant declines of ADC values (27% to 45%) occurred in the entire brain. Glucose infusion normalized most of the ADC changes, even after a 50-minute period of isoelectricity.

CONCLUSIONS

ADC mapping during hypoglycemia clearly demonstrates changes likely related to energy depletion. Most of these ADC declines were reversible. Hypoglycemia is a condition known to be associated with shrinkage of the extracellular space. These observations support the hypothesis that ADC reductions observed in ischemia are also related to shifts of water from the extracellular to the intracellular compartment.

Effects of CD11b/18 monoclonal antibody on rats with permanent middle cerebral artery occlusion

The progression of a lesion from ischemic injury to infarct, after the permanent occlusion of a middle cerebral artery, may be influenced by the influx of leukocytes into the ischemic territory. We aimed to evaluate the effectiveness of treating rats that had permanent middle cerebral artery occlusion with a single dose of an anti-CD11b/18 monoclonal antibody injected 1 hour after the arterial occlusion. To mimic the clinical situation of patients with ischemic strokes who may be treated within 1 hour of the ischemic event, the artery remained occluded. Forty-one adult Wistar rats had permanent middle cerebral artery occlusion, and one was subjected to a sham operation. One hour later, 22 rats received CD11b/18 monoclonal antibody and an additional 20 were injected either with a nonspecific antibody (n = 10) or a buffer solution (n = 10). Experiments were terminated at intervals ranging 12 to 96 hours after the arterial occlusion. Endpoints included neurological testing, daily evaluation of body weight, counts of white blood cells in the peripheral blood, measurement of the area of pallor in the ischemic hemisphere, counts of necrotic neurons, and counts of leukocytes sequestered in the ischemic hemisphere. In experiments terminated 12 hours after the arterial occlusion (n = 4), there were fewer necrotic neurons in the group treated with the CD11b/18 monoclonal antibody compared with the two controls (P < .05), but this difference was not reflected in the neurological scores. Numbers of necrotic neurons in experiments terminated > 12 hours later were not different among the three subgroups. White blood cell counts in peripheral blood were lower in animals with arterial occlusion injected with the monoclonal antibody CD11b/18 (P < .05); numbers of leukocytes sequestered in the ischemic hemisphere were not different in the three groups. Neither changes in body weight nor in the volume of the area of pallor were significantly different among the three groups.

Influence of gender and age at onset on the HLA associations in Chinese with insulin-dependent diabetes mellitus

IDDM in Singaporean Chinese was associated with HLA B58, DRB1*0301, DQB1*0201, and joint occurrences of DRB1*0301/*0901 and DRB1*0301/*04. Of the DR4s the frequencies of DRB1*0401, *0404, and *0405 were higher and *0406 was lower in patients compared to controls. DRB1*0301/*0901 was observed mainly in female patients and the frequency showed an inverse relationship with age at onset, whereas DRB1*0301/*04 was observed mainly in male patients and also showed an inverse relationship with age at onset. DRB1*1202 showed an increasing frequency with age at onset. IDDM patients had a higher frequency of homozygous NAsp57 DQ beta chains and a lower frequency of homozygous Asp57 DQ beta chains compared to controls, especially in younger onset patients.

Interleukin-1 receptor antagonist decreases the number of necrotic neurons in rats with middle cerebral artery occlusion

Marked increases in the brain expression of interleukin (IL)-1 have been reported in rats after permanent occlusion of a large cerebral artery. Interactions between endothelial cells and leukocytes have been implicated in the pathogenesis of several types of ischemic injury to the myocardium and other organs. In this study we asked whether inhibiting the effects of IL-1 would affect the outcome of an experimental brain infarct. Adult male Wistar rats (n = 13) with permanent occlusion of the middle cerebral artery were given IL-1 receptor antagonist. A second group (n = 13) with the same type of brain injury was given a placebo. A third group, subjected to a sham operation, was given either IL-1 receptor antagonist (n = 2) or a placebo (n = 2). Experiments were terminated after either 24 hours or 7 days. Compared with the control group, animals treated with IL-1 receptor antagonist improved their neurological score (P < 0.05), experienced less pronounced changes in body weight (P < 0.05), and had fewer necrotic neurons (P < 0.001) and fewer leukocytes in the ischemic hemisphere (P < 0.001) as well as a smaller area of pallor (P < 0.05) in the ischemis hemisphere. The results suggest that inhibiting the proinflammatory effects of IL-1 with a receptor antagonist is an effective way of influencing the leukocyte responses elicited by an arterial occlusion. Such leukocyte inhibition seemingly attenuates the number of necrotic neurons resulting from the occlusion of a large brain artery.

Neuronal necrosis after middle cerebral artery occlusion in Wistar rats progresses at different time intervals in the caudoputamen and the cortex

BACKGROUND AND PURPOSE

Most brain lesions that develop after an artery is occluded evolve from an initial stage of "ischemic injury" (probably reversible) to an infarct or an area where most neurons become necrotic. There is scant information on the time that must elapse after the arterial occlusion for neurons to undergo irreversible injury. The objective of these experiments was to chart the time course and the topographic distribution of the neuronal necrosis that follows the occlusion of a large cerebral artery.

METHODS

One hundred fifty-one adult rats (including 15 controls) were used in this study. One hundred forty-seven had the right middle cerebral artery occluded for variable periods ranging from 30 minutes to 7 days. After processing the brains for histology, a meticulous structural evaluation of each specimen, including quantitation of necrotic neurons, was followed by a detailed statistical analysis of the neuronal counts.

RESULTS

Few neurons in isolated sites showed morphological signs of necrosis during the initial 4 hours; the first significant increase in the percentage of necrotic neurons (15%) was observed within the territory of the occluded artery after 6 hours (P < .05); 12 hours after the arterial occlusion most neurons (65%) had become necrotic (P < .0001). Pannecrosis involving neurons, glial cells, and blood vessels was observed at 72 to 96 hours. However, even at this time pannecrosis involved only the preoptic area and the lateral putamen; a few intact neurons remained visible in the cortex, and scattered necrotic neurons could be identified beyond the edges of the "area of pallor," which does not become clearly demarcated until 4 to 5 days after the arterial occlusion.

CONCLUSIONS

There is a predictable progression in the development of neuronal necrosis after a permanent arterial occlusion. Irreversible changes appear first in the caudoputamen and then spread to the cortex. The causes for the progression of the lesion are not known; however, therapeutic interventions that start within the first 1 to 2 hours after the arterial occlusion may alter the histopathologic responses to this form of injury. It remains to be determined whether the extent of the neurological deficit induced by an arterial occlusion correlates with the number of necrotic neurons.

Neurological deficit and extent of neuronal necrosis attributable to middle cerebral artery occlusion in rats. Statistical validation

BACKGROUND AND PURPOSE

Occluding a large intracranial artery in rats produces a brain lesion that grows in terms of an increase in both surface area and number of necrotic neurons. The present study investigated whether reperfusing the ischemic territory 30 to 60 minutes after the arterial occlusion would have a beneficial effect on either the clinical or the histological outcome of the lesion.

METHODS

One hundred four adult rats (including appropriate controls) were used; 97 had a middle cerebral artery occluded by inserting a nylon monofilament via the right external carotid artery. The arterial occlusion was transient in two groups and permanent in another; survival times were comparable for all groups. Control animals were subjected to a sham operation during which the artery was occluded for less than 1 minute. The outcome was evaluated by measuring the extent of the neurological deficit and the severity of the histological injury.

RESULTS

Mean neurological score and mean number of necrotic neurons in the cortex were more favorable after transient (30- to 60-minute) compared with permanent arterial occlusion (P < .005). Moreover, the correlation between mean neurological score and mean number of necrotic neurons was highly significant: r = .951; P < .001.

CONCLUSIONS

The histological effects of an intracranial arterial occlusion in the adult rat can be predicted on day 1 by the neurological score described in this report. Significant improvement can be obtained in these animals by reestablishing arterial flow 60 minutes or sooner after the ictus. The pattern of cortical pannecrosis observed after permanent occlusion (> or = 72 hours) was transformed into incomplete ischemic injury in most instances of transient occlusion.

Brain microvessels: factors altering their patency after the occlusion of a middle cerebral artery (Wistar rat)

The progression from ischemic injury to pannecrosis that occurs in the rat brain several hours after occluding a large artery may be partly attributable to a worsening of the circulation through the microvessels. The objective of this study was to quantitate selected structural changes involving astrocytes and endothelial cells within an area of focal brain ischemia created by the occlusion of a middle cerebral artery. The magnitude of these structural changes was correlated with alterations in the patency to a circulating macromolecule through the microvessels (< or = 15 mu in diameter) located within the territory of the occluded artery. One hundred eighty-five adult male Wistar rats had the right middle cerebral artery occluded after threading a nylon monofilament through the external carotid artery. Experiments were terminated by either cardiovascular perfusion or decapitation and immersion fixation at intervals ranging between 30 minutes and 7 days after the arterial occlusion. Randomly selected animals from each experimental subgroup were injected intravenously with horseradish peroxidase (molecular weight 44 kd) approximately 20 minutes before death. The progressive decline in the area fraction comprised by the vessels filled with horseradish peroxidase was preceded at 30 to 60 minutes by an increase in the surface area occupied (on a cross-section of a microvessel) by endothelial cells (both nucleus and cytoplasm). This was followed by an increase of 23.7% in the mean diameter of astrocytes nuclei and a decrease of approximately 35% in lumenal surface of the microvessels. These observations suggest that the occlusion of a large cerebral artery causes prompt swelling of endothelial cells and astrocytes; both of these early biological responses may interfere with erythrocyte circulation and oxygen delivery, which (after the arterial occlusion) are entirely dependent on the circulation provided by the collateral arterial connections. Through its interference with microvascular patency and oxygen delivery, cell swelling may influence the rate at which neurons become necrotic. In this model of brain infarct the number of necrotic neurons peaks approximately 72 hours after middle cerebral artery occlusion.(ABSTRACT TRUNCATED AT 400 WORDS)

Influx of leukocytes and platelets in an evolving brain infarct (Wistar rat)

The results of several experimental studies of focal ischemia and anecdotal observations suggest that leukocytes may contribute to the injury initiated by an arterial occlusion. The timing and the nature of leukocyte responses in evolving brain infarcts (either human or experimental) are incompletely characterized. This is a study of experimental brain lesions in 96 Wistar rats that underwent occlusion of a large intracranial artery for variable intervals ranging between 30 minutes and 7 days. The experimental model, based on the occlusion of a middle cerebral artery ostium via the insertion of a nylon monofilament through the external carotid artery, does not require opening the skull; therefore, the inflammatory response is not influenced by the effects of craniotomy and changes in intracranial pressure are only those induced by the ischemic lesion. All 96 animals having the same type of arterial occlusion developed an ischemic brain lesion (limited to the territory of the corresponding artery) that evolved into an area of extensive neuronal necrosis over a period of 6 to 12 hours followed by pan-necrosis (infarct) approximately 60 hours later. In this study, leukocytes (in particular polymorphonuclear cells) were detected in the microvessels (capillaries and venules) of the ischemic hemisphere as early as 30 minutes after the arterial occlusion. Numbers of intravascular neutrophils peaked at 12 hours, whereas intraparenchymal granulocytes were most numerous at 24 hours; a few granulocytes were visible in the brain infarct as late as day 7. Circulating monocytes were first detected within the capillaries/venules of the ischemic area after 4 to 6 hours. Platelet aggregates were more abundant in the arterial than the venous side of the circulation, and luminal obstruction of arteries by platelet aggregates became noticeable only 48 hours after the arterial occlusion. Fibrin thrombi were conspicuous for their absence. These observations provide the background for studies that will attempt to unravel the relationship between the biological responses of leukocytes and neuronal necrosis secondary to focal ischemia.

In situ observation of inflammatory cell-tumor cell interaction in human seminomas (germinomas): light, electron microscopic, and immunohistochemical study

The precise functional significance of the inflammatory cells that infiltrate seminomas remains poorly understood. The present study analyzed 15 cases of testicular and extragonadal seminomas (germinomas) by light and electron microscopy, as well as by immunohistochemical methods, with emphasis on the inflammatory cell-tumor cell interaction. Ultrastructurally, in all 15 cases the lymphocytes (mainly consisting of small lymphocytes) were found to be in intimate contact with the intact tumor cells and with those that displayed damage of varying degree. In particular, relatively early damage, such as local loss of the membrane and/or cytoplasm, occurred at the contact regions. Often, the lymphocytes penetrated deeply into the cytoplasm, even into the nucleus of the tumor cell. In spite of the severe damage to the tumor cells, the lymphocytes were themselves intact. The stromal cells contacted by lymphocytes did not show damage. The tumor cells were in contact with epithelioid cells of granulomas in six cases and scattered macrophages in 11 cases showed damage similar to that seen in tumor cells in contact with lymphocytes. The great majority of the lymphocytes were UCHL1-positive cells. L26- or Leu-7-positive cells were rarely found. The epithelioid cells and scattered macrophages were positive for MAC387. The present morphologic study suggests that the infiltrating lymphocytes, epithelioid cells (probably derived from macrophages), and macrophages may be directly cytotoxic to the tumor cells in the microenvironments of testicular and extragonadal seminomas (germinomas).