[Long-term efficacy of robotic radical total gastrectomy for gastric cancer and analysis of prognostic factors].

Objective: To analyze long-term outcomes and prognostic factors of gastric cancer patients after robotic radical total gastrectomy. Methods: A retrospective case-control study was conducted. Inclusion criteria: (1) receiving robotic radical total gastrectomy; (2) gastric adenocarcinoma was confirmed by postoperative pathology; (3) no previous history of other malignant tumors; (4) no preoperative chemotherapy or radiation therapy performed. Exclusion criteria: (1) age <18 years old or age >80 years old;(2)distant metastasis before surgery, or palliative surgery; (3) conversion to laparotomy;(4) R1 or R2 resection; (5)emergency surgery; (6) remnant gastric cancer or recurrence; (7)died of severe complications during hospitalization or within 1 month after surgery. Overall survival rates (OS) and disease-free survival rates (DFS) were evaluated using the Kaplan-Meier method. Cox regression analysis was used to identify prognosis factors for overall survival. Results: According to the above criteria, 166 gastric cancer patients who underwent robotic radical total gastrectomy between March 2010 and November 2018 were included in this study. Roux-en-Y reconstruction was performed in all patients. Reconstruction were achieved using extracorporeal method through a minilaparotomy in 149 case and intracorporeal anastomosis in 17 cases. The number of harvested lymph nodes was (34.8±17.5), and the number of harvested lymph nodes at group 2 was (10.1±6.7). The number of patients with lymph node metastasis of group 2 was 73 (44.0%). The median follow-up time was 25 months (range 2-109). There were 55 (33.1%) cases of recurrence during follow-up. The 3- and 5-year overall survival rates were 55.8% and 46.2% respectively. The 3- and 5-year disease-free survival rates were 53.4% and 45.4% respectively. The 5-year overall survival rates grouped based on TNM stage were 78.9% for stage I, 58.5% for stage II, and 37.1% for stage III. The 5-year disease-free survival rates grouped based on TNM stage were 78.9% for stage I, 59.2% for stage II, and 34.6% for stage III. Univariate analysis suggested that TNM stage, the number of harvested lymph nodes and number of harvested lymph nodes at group 2 were associated with overall survival rates (all P<0.05). Multivariate analyses revealed that TNM stage (P<0.001; stage IIIB: HR=5.357, 95%CI:1.182 to 24.275; stage IIIC: HR=11.937, 95%CI: 2.677 to 53.226) and number of harvested lymph nodes at group 2 (P=0.034; 6-10: HR=0.562,95%CI:0.326 to 0.969; >10: HR=0.388, 95%CI: 0.176 to 0.857) were independent prognostic factors for overall survival. Conclusion: The long-term outcomes of robotic radical total gastrectomy were satisfactory. TNM stage and number of harvested lymph nodes at group 2 were independent prognostic factors for overall survival.

Long non-coding RNA FTX promotes gastric cancer progression by targeting miR-215.

OBJECTIVE: Gastric cancer (GC) is one of the most common malignant tumors in the world, which is seriously harmful to people's health. The increasing number of studies have shown that long non-coding RNA (lncRNA) is related to the occurrence of gastric cancer. In this study, we aimed at investigating the role of lnc FTX in the occurrence of gastric cancer. MATERIALS AND METHODS: The expression of FTX in gastric cancer patients and gastric cancer cell lines was detected by RT-qPCR. Univariate Kaplan-Meier method was used to analyze the relationship between FTX expression level, clinicopathological parameters and overall survival rate (OS). After transferring si-FTX and overexpression FTX plasmids into MGC-803 and SGC-7901, the expression of miR-215-3p was detected by RT-qPCR, and the changes of cell proliferation and cell cycle were detected by CCK-8 and flow cytometry. In addition, luciferase activity was used to detect whether miR-215-3p combined with FTX and SIVA1. Finally, Western blot (WB) was used to detect the change of SIVA1 protein expression by miR-215 mimic. RESULTS: We found that the expression of FTX in tumor tissues of 71 GC patients was higher than that in paracancerous tissues, and the prognosis of patients with high FTX was poor. The expression of FTX in gastric cancer cells was higher than that in normal human gastric epithelial cells (GES-1). Transferring overexpression plasmid of FTX into gastric cancer cells (MGC-803 and SGC-7901) promoted cell proliferation and the ratio of cells in G0-G1 phase was decreased. Transferring si-FTX to MGC-803 and SGC-7901 led to opposite results. There was a negative correlation between the expression of mi215-3p and FTX in MGC-803 and SGC-7901 gastric cancer cells, and luciferase results showed that mi215-3p could directly bind to FTX and regulate cell growth and cell cycle changes. In addition, luciferase results showed that mi215-3p could bind directly to SIVA1. What's more, RT-qPCR and WB results showed that mi215 mimic could promote the expression of MGC-803, SGC-7901 SIVA1mRNA and protein. CONCLUSIONS: According to these results, this study revealed that the previously neglected FTX-miR2153p-SIVA1 regulatory axis for the regulation of gastric cancer progression, which may be a potential target for the treatment of gastric cancer.

The promotion of the transformation of quiescent gastric cancer stem cells by IL-17 and the underlying mechanisms.

Postoperative recurrence and metastasis have crucial roles in the poor prognosis of gastric cancer patients. Previous studies have indicated that gastric cancer originates from cancer stem cells (CSCs), and some investigators have found that a particular subset of CSCs possesses higher metastatic capacity. However, the specific mechanism remains uncertain. In the present study, we aimed to explore the biological functions of the inflammatory cytokine interleukin-17 (IL-17) in gastric cancer metastasis and the distinct IL-17-induced transformation of quiescent gastric CSCs. Our results showed that invasive gastric CSCs were CD26+ and CXCR4+ and were closely associated with increased metastatic ability. The quiescent gastric CSCs, which were CD26- and CXCR4-, were exposed to appropriate concentrations of IL-17; this resulted in the decreased expression of E-cadherin and the increased expression of vimentin and N-cadherin. In addition, the upregulation of IL-17 both in vitro and in vivo resulted in a significant induction of invasion, migration and tumor formation ability in gastric CSCs compared with the control group, which was not treated with IL-17. Further experiments indicated that the activation of the downstream phosphorylated signal transducer and activator of transcription 3 (STAT3) transcription factor pathway was facilitated by IL-17. On the contrary, the downregulation of STAT3 by the specific inhibitor Stattic significantly reversed the IL-17-induced epithelial-mesenchymal transition (EMT)-associated properties of quiescent gastric CSCs. Moreover, tumorigenesis and metastasis were suppressed. Taken together, we suggest that IL-17 is positively correlated with the transformation of quiescent gastric CSCs into invasive gastric CSCs and that targeting IL-17 may emerge as a possible novel therapeutic strategy for gastric cancer.

Geometric Parameter Analysis of Ruptured and Unruptured Aneurysms in Patients with Symmetric Bilateral Intracranial Aneurysms: A Multicenter CT Angiography Study.

BACKGROUND AND PURPOSE: Previous studies of geometric and morphologic parameters of intracranial aneurysms have been conducted to determine rupture risk, which remains incompletely defined due to patient-specific risk factors, such as sex, hypertension, and age. To this end, we compared characteristics of ruptured and unruptured aneurysms in the same patients with symmetric bilateral intracranial aneurysms. MATERIALS AND METHODS: Between January 2008 and March 2014, 2361 patients with 2674 aneurysms were diagnosed by CT angiography or surgical findings at 4 medical centers. Geometric and morphologic parameters examined for symmetric bilateral intracranial aneurysms comprised aneurysm wall regularity, size, neck width, aspect ratio, size ratio, neck-to-parent artery ratio, and area ratio. Univariate and multivariate statistical analyses were performed to determine independent risk factors for rupture. RESULTS: Sixty-three patients (48 women, 15 men; mean age, 62.5 ± 9.8 years) with symmetric bilateral aneurysms were eligible for the study and were included. The most frequent aneurysm location was the posterior communicating artery. Univariate analysis disclosed that aneurysm size, aspect ratio, size ratio, area ratio, and irregular wall differed between patients with ruptured and unruptured aneurysms. Multivariate analysis indicated that aspect ratio of ≥1.6 (adjusted OR, 9.521; 95% CI, 2.182-41.535), area ratio of ≥1.5 (adjusted OR, 4.089; 95% CI, 1.247-13.406), and irregular shape (adjusted OR, 10.443; 95% CI 3.394-32.135) were significant predictive factors for aneurysm rupture after adjustment for aneurysm size. CONCLUSIONS: An aspect ratio of ≥1.6, area ratio of ≥1.5, and irregular wall are associated with aneurysm rupture independent of aneurysm size and patient characteristics. These characteristics alone can help in distinguishing ruptured bilateral intracranial aneurysms from unruptured ones.

Effects of hyperglycemic and normoglycemic cerebral ischemia on phosphorylation of c-jun NH2-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK).

Transient global cerebral ischemia leads to delayed neuronal cell death in the hippocampal CA1, caudate putamen and neocortex. If preischemic hyperglycemia exists, the same duration of ischemia recruits additional brain structures, such as dentate gyrus to become damaged. The objective of the present study is to determine whether activation of mitogen-activated protein kinases (MAPKs) plays a role in hyperglycemia-mediated ischemic neuronal damage. Using phopho-specific antibodies against c-jun NH2-terminal kinase (JNK) and p38 MAPK, we studied activation of these two MAPKs in ischemia-vulnerable neocortex and ischemia-resistant dentate gyrus in rats subjected to 15 min of forebrain ischemia and followed by 0.5, 1 and 3 hr of recirculation under normo- and hyperglycemic conditions. The results showed that levels of phosphorylated JNK increased in both normo- and hyperglycemic brains following blood reperfusion for 0.5 hr and persisted up to 3 hr in the neocortex but not in the dentate gyrus, implying JNK may play a role in mediating neuronal cell death after ischemia. However, since hyperglycemia did not further increase phospho-JNK, JNK may not contribute to the detrimental effect of hyperglycemia on neuronal cell death. The amount of phospho-p38 was not altered by ischemia under both normo- and hyperglycemic conditions, suggesting that p38 MAPK may not play a major role in mediating neuronal damage in these two structures.

NXY-059, a nitrone with free radical trapping properties inhibits release of cytochrome c after focal cerebral ischemia.

Recent studies have demonstrated that disodium 2,4-disulfophenyl-N-tert-butylnitrone (NXY-059), a novel nitrone with free radical trapping properties, has a considerable neuroprotective effect against cerebral ischemic injury. The mechanisms of its action have not been fully defined. In order to evaluate whether NXY-059 exerts its protective effects by inhibiting the release of cytochrome c, a key initiator of programmed cell death pathway, we have studied the effects of NXY-059 on reducing infarct volume and on inhibiting cytochrome c release from the mitochondria after transient focal cerebral ischemia. Wistar rats were subjected to 2 hr of middle cerebral artery occlusion and perfusion-fixed after 4, 6, 12, and 24 hr of reperfusion. NXY-059 (30 mg/kg) was i.v. injected 1 hr after reperfusion and followed immediately by 30 mg/kg/hr continuous i.v. infusion for the entire reperfusion period. The results showed that NXY-059 reduced infarct volume from 37.2% to 12.5% (p<0.0001). Immunocytochemistry demonstrated that the release of cytochrome c increased at 6 hr, peaked at 12 and 24 hr of reperfusion. NXY-059 treatment prevented ischemia-induced cytochrome c release. NXY-059 may reduce ischemic brain damage through suppressing the cell death pathway that is initiated by cytochrome c release.

Free radical spin trap alpha-phenyl-N-tert-butyl-nitron inhibits caspase-3 activation and reduces brain damage following a severe forebrain ischemic injury.

It has been documented that alpha-phenyl-N-tert-butyl-nitron (PBN) possesses a potent neuroprotective effect when administered after transient focal cerebral ischemia. However, contradicting results were reported regarding its effect in transient global ischemia. To further elucidate the mechanism of PBN action, we have studied the effect of PBN on animal survival, histopathological outcome, and activation of caspase-3 following 30 min of global ischemia in vehicle- and PBN-treated rats. The results showed that 30 min of global ischemia was such a severe insult that no animal could survive beyond 2 d of reperfusion. Histopathological evaluation showed severe tissue edema and microinfarct foci in the neocortex and thalamus. Close to 100% damage was observed in the stratum and hippocampal CA1, CA3, and dentate gyrus subregions. Postischemic PBN treatment significantly enhanced animal survival and reduced damage in the neocortex, thalamus, and hippocampus. Immunohistochemistry demonstrated that caspase-3 was activated following ischemia in the striatum and the neocortex. PBN suppressed the activation of caspase-3 in both structures. It is concluded that PBN is a potent neuroprotectant against both focal and global ischemia; besides its function as a free radical scavenger, PBN may reduce ischemic brain damage by blocking cell death pathways that involve caspase-3 activation.

Does long-term glucose infusion reduce brain damage after transient cerebral ischemia?

A recent study reported that hyperglycemia of a brief duration worsens, and of long duration reduces, ischemic brain damage. To test whether this is a valid conception, we induced 10 min of transient forebrain ischemia, recorded postischemic seizures, and evaluated brain morphology. The results showed that administration of glucose 2 h before ischemia aggravated brain damage, induced seizures, and caused animal death in the same manner as was previously observed when glucose was given 30 min before ischemia. Thus, the conclusion that the influence of glucose on an ischemic transient is dependent upon the duration of hyperglycemia is unsubstantiated.

Hyperglycemia enhances DNA fragmentation after transient cerebral ischemia.

Previous histopathologic results have suggested that one mechanism whereby hyperglycemia (HG) leads to exaggerated ischemic damage involves fragmentation of DNA. DNA fragmentation in normoglycemia (NG) and HG rats subjected to 30 minutes of forebrain ischemia was studied by terminal deoxynucleotidyl transferase mediated DNA nick-labeling (TUNEL) staining, by pulse-field gel electrophoresis (PFGE), and by ligation-mediated polymerase chain reaction (LM-PCR). High molecular weight DNA fragments were detected by PFGE, whereas low molecular weight DNA fragments were detected using LM-PCR techniques. The LM-PCR procedure was performed on DNA from test samples with blunt (without Klenow polymerase) and 3'-recessed ends (with Klenow polymerase). In addition, cytochrome c release and caspase-3 activation were studied by immunocytochemistry. Results show that HG causes cytochrome c release, activates caspase-3, and exacerbates DNA fragments induced by ischemia. Thus, in HG rats, but not in control or NGs, TUNEL-stained cells were found in the cingulate cortex, neocortex, thalamus, and dorsolateral crest of the striatum, where neuronal death was observed by conventional histopathology, and where both cytosolic cytochrome c and active caspase-3 were detected by confocal microscopy. In the neocortex, both blunt-ended and stagger-ended fragments were detected in HG, but not in NG rats. Electron microscopy (EM) analysis was performed in the cingulate cortex, where numerous TUNEL-positive neurons were observed. Although DNA fragmentation was detected by TUNEL staining and electrophoresis techniques, EM analysis failed to indicate apoptotic cell death. It is concluded that HG triggers a cell death pathway and exacerbates DNA fragmentation induced by ischemia.

Cyclosporin A, but not FK506, prevents the downregulation of phosphorylated Akt after transient focal ischemia in the rat.

The two immunosuppressants, cyclosporin A (CsA) and FK506, when given 1 and 3 h after the start of reperfusion following 2 h of middle cerebral artery (MCA) occlusion, reduce infarct volume to 30% of control. This suggests a common effect, e.g. one due to suppression of the activation of calcineurin. However, when given by the intracarotid (i.c.) route after only 5 min of recirculation CsA, but not FK506, reduced infarct volume even further, to 10% of control. This was attributed to the fact that CsA, but not FK506, block the in vitro assembly of a mitochondrial permeability transition (MPT) pore. The present experiments were undertaken to further characterize the anti-ischemic effect of CsA, when given i.c. 5 min after recirculation and to explore why CsA, when given at that time, is more efficacious than FK506. It was established that the i.c. administration of CsA in a dose of 10 mg/kg increased the tissue concentration of CsA 2- to 3-fold, when compared to the i.v. administration. CsA proved to be effective in reducing infarct volume even when the tissue damage was assessed by histopathology after 7 days of recovery. MCA occlusion of 2 h duration caused a sustained decrease in the phosphorylation Akt at threonine 308. Since this down regulation of Akt was prevented by CsA, the results suggested a link between dephosphorylaltion of Bad, and cell death. Interestingly FK506 did not prevent down regulation of Akt, it thus seems unlikely that the anti-ischemic effect of CsA is related to its association with cytosolic cyclophilin.

Effects of intracarotid arterial injection of cyclosporin A and spontaneous hypothermia on brain damage incurred after a long period of global ischemia.

A recent study showed that a single intracarotid arterial injection of cyclosporin A (CsA) can dramatically reduce infarct volume in rats subjected to transient focal ischemia. The present experiments were undertaken to investigate whether intracarotid arterial injection of CsA reduces brain damage after global ischemia. Since hypothermia is also an efficacious factor in preventing ischemic brain damage, in the second part of the experiments we tested whether a combination of hypothermia and CsA would provide additional brain protection. Global ischemia of a 30-min duration was induced in the rat. CsA (10 mg/kg) was injected into the carotid artery immediately after reperfusion. Hypothermia was instituted after ischemia by allowing spontaneous head temperature to fall to 30-32 degrees C, while body temperature was upheld at 37 degrees C. The results demonstrated that vehicle-treated animals could not survive beyond 1-2 days after reperfusion, and the histopathological outcome in a separate group of rats perfusion-fixed after 1 day reperfusion showed 80-100% brain damage in the caudoputamen, and in the hippocampal CA1, CA3, CA4 and dentate gyrus subregions. Microinfarction and grade 3 damage were frequently observed in the cingulate and parietal cortex and in the thalamus. CsA moderately prolonged animal survival to 3 days after reperfusion and reduced brain damage to grade 2 in the cortical areas and the thalamus. Hypothermia further increased animal survival to at least 6 days after reperfusion and reduced brain damage to 30% in the caudoputamen, to close to zero in the CA3, CA4, and dentate gyrus, and to grade 1-2 in the cortical areas and the thalamus. The combination of hypothermia and CsA did not give additional protection.

Phosphorylation of extracellular signal-regulated kinase after transient cerebral ischemia in hyperglycemic rats.

The present study was undertaken to investigate whether extracellular signal-regulated kinase (ERK) was involved in mediating hyperglycemia-exaggerated cerebral ischemic damage. Phosphorylation of ERK 1/2 was studied by immunocytochemistry and by Western blot analyses. Rats were subjected to 15 min of forebrain ischemia, followed by 0.5, 1, and 3 h of reperfusion under normoglycemic and hyperglycemic conditions. The results showed that in normoglycemic animals, moderate phosphorylation of ERK 1/2 was transiently induced after 0.5 h of recovery in cingulate cortex and in dentate gyrus, returning to control values thereafter. In hyperglycemic animals, phosphorylation of ERK 1/2 was markedly increased in the cingulate cortex and dentate gyrus after 0.5 h of recovery, the increases being sustained for at least 3 h after reperfusion. Hyperglycemia also induced phosphorylation of ERK 1/2 in the hippocampal CA3 sector but not in the CA1 area. Thus, the distribution of phospho-ERK 1/2 coincides with hyperglycemia-recruited damage structures. The results suggest that hyperglycemia may influence the outcome of an ischemic insult by modulating signal transduction pathways involving ERK 1/2.

[The status and prospects of X-ray photographs marking technology].

This article introduces three different marking technologies used in clinical radiation photography at present and their respective theories, their advantages and disadvantages, analyzes the space-time and technology conditionality of different marking technologies in selecting mark messages. In the future, new marking technology will be fused with the cassette into one and will contain message as much as possible on photograph marks in order to satisfy the need of technicians and doctors.

Cyclosporin A enhances survival, ameliorates brain damage, and prevents secondary mitochondrial dysfunction after a 30-minute period of transient cerebral ischemia.

Cyclosporin A (CsA) has been shown to be efficacious in protecting against ischemic injury after short periods (5 to 10 min) of forebrain ischemia. The present experiments were undertaken to study if a long period of forebrain ischemia (30 min), induced at a brain temperature of 37 degrees C, is compatible with survival and if the brain damage incurred can be ameliorated by CsA. The results showed that animals subjected to 30 min of forebrain ischemia at a brain temperature of 37 degrees C failed to survive after the first 24 h of recovery and showed extensive neuronal necrosis in all selectively vulnerable regions after 1 day of survival. CsA, when injected in combination with an intracerebral lesion to open the blood-brain barrier, markedly prolonged the survival time. CsA-injected animals also showed amelioration of histological lesions, an effect that was sustained for at least 4 days. Experiments with mitochondria isolated from the neocortex and hippocampus showed that state 3 respiratory rates decreased during ischemia, recovered after 1 and 3 h of recirculation, and then showed a secondary decline at 6 h. Administration of CsA prevented this secondary decline. Measurements of neocortical cerebral blood flow showed that there was no secondary hypoperfusion prior to secondary mitochondrial dysfunction, implying that changes in blood flow may not be responsible for the rapidly developing, secondary brain damage. The results thus demonstrate that if brain temperature is upheld at 37 degrees C, a 30-min period of ischemia is not compatible with survival after the first day of recovery, and gross histopathological damage develops within that period. CsA was efficacious in prolonging animal survival, ameliorating brain damage, and preventing the secondary mitochondrial dysfunction. Since CsA blocks the mitochondrial permeability transition pore its action may, at least in part, be on mitochondrial integrity and function.

Is neuronal injury caused by hypoglycemic coma of the necrotic or apoptotic type?

In this study, we explored if a 30 minute period of hypoglycemic coma yields damage which shows some features associated with apoptosis. To that end, we induced insulin-hypoglycemic coma of 30 min duration, and studied brain tissues after the coma period, and after recovery period of 30 min, 3 h, and 6 h. Histopathological data confirmed neuronal damage in all of the vulnerable neuronal populations. Release of cytochrome c (cyt c), assessed by Western Blot, was observed in the neocortex and caudoputamen after 3 and 6 h of recovery. In these regions, the caspase-like activity increased above control after 6 h of recovery. By laser-scanning confocal microscopy, a clear expression of Bax was observed after 30 min of coma in the superficial layers of the neocortex, reaching a peak after 30 min of recovery. Punctuate immunolabeling surrounding nuclei in soma and dendrites in cortical pyramidal neurons likely represents mitochondria, which suggests that Bax protein assembled at the surface of mitochondria in vulnerable neocortical neurons. It is concluded that although previous morphological data have suggested that cells die by necrosis, neuronal damage after hypoglycemic coma shows some features of apoptosis.

Hyperglycemia enhances extracellular glutamate accumulation in rats subjected to forebrain ischemia.

BACKGROUND AND PURPOSE: An increase in serum glucose at the time of acute ischemia has been shown to adversely affect prognosis. The mechanisms for the hyperglycemia-exacerbated damage are not fully understood. The objective of this study was to determine whether hyperglycemia leads to enhanced accumulation of extracellular concentrations of excitatory amino acids and whether such increases correlate with the histopathological outcome. METHODS: Rats fasted overnight were infused with either glucose or saline 45 minutes before the induction of 15 minutes of forebrain ischemia. Extracellular glutamate, glutamine, glycine, taurine, alanine, and serine concentrations were measured before, during, and after ischemia in both the hippocampus and the neocortex in both control and hyperglycemic animals. The histopathological outcome was evaluated by light microscopy. RESULTS: There was a significant increase in extracellular glutamate levels in the hippocampus and cerebral cortex in normoglycemic ischemic animals. The increase in glutamate levels in the cerebral cortex, but not in the hippocampus, was significantly higher in hyperglycemic animals than in controls. Correspondingly, exaggerated neuronal damage was observed in neocortical regions in hyperglycemic animals. CONCLUSIONS: The present results demonstrate that, at least in the neocortex, preischemic hyperglycemia enhances the accumulation of extracellular glutamate during ischemia, providing a tentative explanation for why neuronal damage is exaggerated.

Production of hydroxyl free radical by brain tissues in hyperglycemic rats subjected to transient forebrain ischemia.

Preischemic hyperglycemia is known to aggravate brain damage resulting from transient ischemia. In the present study, we explored whether this aggravation is preceded by an enhanced formation of reactive oxygen species (ROS) during the early reperfusion period. To that end, normo- and hyperglycemic rats were subjected to 15 min of forebrain ischemia and allowed recovery periods of 5, 15, and 60 min. Sodium salicylate was injected intraperitoneally in a dose of 100 mg/kg, and tissues were sampled during recirculation to allow analyses of salicylic acid (SA) and its hydroxylation products, 2,3- and 2,5-dihydroxybenzoate (DHBA). Tissue sampled from thalamus and caudoputamen in normoglycemic animals failed to show an increase in 2,3- or 2,5-DHBA after 5 and 15 min of recirculation. However, such an increase was observed in the neocortex after 60 min of recirculation, with a suggested increase in the hippocampus as well. Hyperglycemia had three effects. First, it increased 2,5-DHBA in the thalamus and caudoputamen to values exceeding normoglycemic ones after 15 min of recirculation. Second, it increased basal values of 2,5- and total DHBA in the neocortex. Third, it increased the 60-min values for 2,5- and total DHBA in the hippocampus. These results hint that, at least in part, hyperglycemia may aggravate damage by enhancing basal- and ischemia-triggered production of ROS.

Hypothermia ameliorates ischemic brain damage and suppresses the release of extracellular amino acids in both normo- and hyperglycemic subjects.

It has previously been shown that hypothermia markedly reduces cellular release of the excitatory amino acid glutamate and ameliorates ischemic damage. Based on extensive data showing that preischemic hyperglycemia exaggerates brain damage due to transient forebrain ischemia we posed the question whether glutamate release during ischemia in hyperglycemic rats is attenuated or prevented by induced hypothermia, and if such attenuation/prevention correlates with amelioration of the characteristic brain damage observed in hyperglycemic subjects. The experiments were performed in rats subjected to a 15-min period of forebrain ischemia, plasma glucose concentration being maintained at approximately 5 mM (control) or approximately 20 mM (hyperglycemia) prior to ischemia. Extracellular amino acid concentrations were measured by HPLC techniques on microdialysis samples which were collected from left dorsal hippocampus and right neocortex, and tissue damage was assessed by histopathology. Hypothermia (30 degrees C), which was induced 45 min prior to ischemia, reduced the neuronal damage not only in the ischemia-vulnerable regions but also in the normally ischemia-resistant areas that are recruited in the damage process in hyperglycemic subjects. The extracellular glutamate concentration was markedly increased in response to the ischemic insult in normothermic-normoglycemic animals. The concentration of glutamate was further increased in normothermic-hyperglycemic animals. Hypothermia inhibited the rise in glutamate concentrations, as well as in the concentrations of other excitatory and inhibitory amino acids. It is discussed whether hypothermia reduces the hyperglycemia-mediated damage by inhibiting extracellular glutamate release during an ischemic transient.

The effect of alpha-phenyl-N-tert-butyl nitrone on bioenergetic state in substantia nigra following flurothyl-induced status epilepticus in rats.

Status epilepticus (SE), i.e. ongoing seizures of more than 30 min duration, gives rise to bilateral pan-necrotic lesions of the substantia nigra, pars reticulata (SNPR). These are known to be preceded by an initial increase, followed by a depression of metabolic rate, and by failure of the bioenergetic state, suggesting mitochondrial dysfunction. We have previously shown that the spin trap alpha-phenyl-N-tert-butyl nitrone (PBN) prevents the lesions caused by 45 min of SE from occurring, in spite of ongoing seizure activity. In this article, we demonstrate that PBN, given 30 min before seizure induction, reduces or prevents the decrease in ATP concentration and adenylate energy charge, without significantly reducing the amount of lactate accumulated, or the decrease in intracellular pH (pHi). The results suggest that the spin trap nitrone preserves the structural and functional integrity of SNPR neurons by protecting the mitochondria against oxidative damage.

Amelioration by cyclosporin A of brain damage in transient forebrain ischemia in the rat.

The immunosuppressant drug cyclosporin A (CsA) is considered to be inherently protective in conditions of ischemia, e.g. in hepatic and cardiac tissue. However, investigations of effects of CsA on neuronal tissue have been contradictory, probably because the blood-brain barrier (BBB) is virtually impermeable to CsA. In the present study, we exploited the finding that the insertion of a syringe needle into brain parenchyma obviously disrupts the BBB and allows influx of CsA, and explored whether CsA, given as intraperitoneal injections daily for 1 week before and 1 week after forebrain ischemia of 7 or 10 min duration, ameliorates the damage incurred to the hippocampal CA 1 sector. In other experiments, the needle insertion and the first i.p. injection of CsA were made 30 min after the start of recirculation, with continued daily administration of CsA during the postinsult week. In animals which were injected with CsA in daily doses of 10 mg kg-1, but in which no needle was inserted, the drug failed to ameliorate CA1 damage, whether the ischemia had a duration of 7 or 10 min. Likewise, needle insertion had no effect on CA1 damage if CsA was not administered. In contrast, when CsA was given to animals with a needle insertion, CA1 damage was dramatically ameliorated, whether treatment was initiated 1 week before ischemia, or 30 min after the start of recirculation. The effect of CsA seemed larger than that of any other drug proposed to have an anti-ischemic effect in forebrain/global ischemia. Injection of tritiated CsA in one animal with BBB disruption lead to detectable radioactivity throughout the ventricular system, suggesting a generalised increase of the entry of CsA across the BBB. The results demonstrate that immunosuppressants of the type represented by CsA markedly ameliorate delayed neuronal damage after transient forebrain ischemia, provided that they can pass the BBB. It is discussed whether the effect of the drug is one involving calcineurin, a protein phosphatase, or if CsA counteracts a permeability transition of the inner mitochondrial membrane, assumed to occur in response to adverse conditions, e.g. gradual accumulation of Ca2+ in the mitochondria in the postischemic period.