[Efficacy of polyetheretherketone rod hybrid surgery in preventing proximal junctional failure after adult spinal deformity surgery].

Objective: To investigate the clinical outcome and preventive effect of polyetheretherketone(PEEK) rod hybrid surgery on proximal junction failure(PJF) after long-segment fusion of adult spinal deformity. Methods: A retrospective study was conducted to analyze patients with degenerative scoliosis/kyphosis who underwent long-segment decompression and fusion surgery at Department of Orthopedics, Peking University First Hospital from January 2017 to December 2021. A total of 75 patients were included in the study, including 14 males and 61 females, aged (67.2±6.8)years (range:55 to 84 years). According to the operation method chosen by the patients, the patients were divided into PEEK rod hybrid group (20 cases) and traditional titanium rod group (55 cases). The general information of the patients was collected, and the coronal and sagittal parameters of the spine were measured before operation, at 1 month after operation, and at the last follow-up. The clinical effect of surgery was judged by the visual analogue scale (VAS) and Oswestry disability index (ODI). Whether proximal junctional kyphosis (PJK) and PJF occurred during the follow-up and the time of occurrence were recorded. Comparisons between groups were performed using independent sample t test, Mann-Whitney U test, χ2 test and Fisher's exact probability method. The data before and after surgery in the same group were compared using the paired sample t test and the Wilcoxon test. Results: There were no significant differences in age, gender, body mass index, bone mineral density, distal instrumented vertebrae, surgical segments, osteotomy method, operation time, and intraoperative bleeding between the two groups (all P>0.05). The follow-up time of the PEEK rod group was shorter(M(IQR)16.5(4.8) vs. 25.0(12.0),Z=-4.230,P<0.01). There were no significant differences in coronal, sagittal parameters, VAS and ODI between the two groups before operation (all P>0.05). Postoperative coronal Cobb angle, pelvic incidence, pelvic tilt, sacral slope, lumbar lordosis, thoracic kyphosis, sagittal vertical axis (SVA), VAS and ODI were significantly improved in both groups(all P<0.05). At the last follow-up, the SVA of the PEEK rod hybrid group was(3.74±2.40)cm, which was significantly lower than that of the titanium rod group (6.28±4.06)cm (t'=-3.318, P=0.002). At the last follow-up, the ODI of the PEEK rod hybrid group was 30.7±6.1, significantly better than the titanium rod group 39.3±17.2(t=-3.203, P=0.046). PJK occurred in 2 patients (10.0%) in the PEEK rod hybrid group, and no PJF phenomenon was observed. In the titanium rod group, 18 patients (32.7%) developed PJK, and 11 patients (20.0%) developed PJF. There was a statistically significant difference in the incidence of PJF between the PEEK rod hybrid group and the titanium rod group (P=0.031). Conclusions: PEEK rod hybrid surgery can achieve good clinical results in the treatment of adult spinal deformities. Compared with traditional titanium rod surgery, it can significantly reduce the incidence of postoperative PJF and improve the clinical function of patients.

[Efficacy of relocation and expansion pharyngoplasty by suspension sutures in the treatment of OSAHS with soft palate oropharyngeal obstruction].

Objective: To explore the efficacy of relocation and expansion pharyngoplasty by suspension sutures in the treatment of obstructive sleep apnea hypopnea syndrome (OSAHS). Methods: Seventy-three patients(including 60 males and 13 females) with OSAHS admitted to the department of otorhinolaryngology of our hospital in recent two years were retrospectively analyzed. All the patients had velopharyngeal obstructionevaluated by electronic endoscopic Müller test and were divided into control group (34 cases) and observation group (39 cases). The patients in the control group were performed modified uvulopalatopharyngoplasty, while those in the observation group were performed relocation and expansion pharyngoplasty by suspension sutures.The scores of ESS, AHI and LSaO2 before and after treatment were collected and compared. Results: The total effective rate of the observation group was 94.87%, which was significantly higher than 79.41% of the control group. The AHI was lower and LSaO2 value was higher (χ2=-1. 896,-1. 968,P<0.05)in the observation group. The sleeping symptoms and quality of life of the two groups were significantly improved. The ESS score of the observation group was decreased more significantly than that of the control group after treatment, and the difference was statistically significant (χ2=-1.451,P<0.05). The incidence of foreign body sensation in pharynx of the observation group (89.74%) was higher than that of the control group (55.88%), and the postoperative bleeding and postoperative recurrence rate (0.00%, 2.56%) was lower than that of the control group (8.82%, 14.70%)with statistical significance (χ2=4.738,4.249,4.119,P<0.05).The incidence of transient nasopharyngeal reflux in both groups was low and statistically insignificant (χ2=0.629,P>0.05). Conclusions: Preoperative strict screening of indications plays an important role in the selection of palatopharyngeal surgery methods and curative effect. Relocation and expansion pharyngoplasty by suspension sutures can improve the clinical efficacy of OSAHS with better safety and less recurrence.

[Curative effect analysis of ultrasound-guided percutaneous radiofrequency ablation for caudate lobe hepatocellular carcinoma].

Objective: To investigate the safety and efficacy of ultrasound-guided percutaneous radiofrequency ablation (RFA) for caudate lobe hepatocellular carcinoma (HCC) and the failure factors of incomplete tumor ablation. Methods: Twenty-four cases with caudate lobe hepatocellular carcinoma who underwent ultrasound-guided percutaneous RFA in the Affiliated Tumor Hospital of Zhengzhou University from January 2017 to October 2019 were enrolled. The ablation effect and complications conditions were recorded, and the primary technical effectiveness and local tumor progression (LTP) were evaluated. Results: Among 24 cases, 20 cases had complete ablation at one session, 4 cases had incomplete ablation, and after supplementary radiofrequency ablation all cases had achieved complete ablation. There was no evidence of local tumor progression in 24 cases after one-month postoperative evaluation. The primary technical effectiveness rate was 100%. The postoperative follow-up was 2 to 29 months (median follow-up time was 18 months). Of the 24 cases after ablation, LTP were detected in 11 cases, of which only 3 cases had distant intrahepatic recurrence, 1 case had distant intrahepatic recurrence and distant metastasis, and 5 cases had only distant metastasis, 2 cases died, and 4 cases had SIR grade B complications related to ablation. Conclusion: Ultrasound-guided percutaneous radiofrequency ablation was safe and effective for caudate lobe hepatocellular carcinoma. In addition, the distance between the tumor and the inferior vena cava < 0.5cm is a suspected risk factor for incomplete ablation of caudate lobe hepatocellular carcinoma (P < 0.05).

[Clinical phenotype of Alport syndrome in monozygotic twins].

Objective: To analyze the consistency of the clinical phenotype of Alport syndrome between monozygotic twins. Methods: This retrospective study included identical twins with Alport syndrome who met the inclusion and exclusion criteria and were admitted to Peking University First Hospital from January 2000 to March 2019. Their clinical data and urinary epidermal growth factor (uEGF) level were extracted from the on-line registry system of hereditary kidney diseases, and analyzed retrospectively. Results: Three pairs of monozygotic twins with X-linked Alport syndrome from three non-consanguineous families were included. The consistency of the genotype status between the twins tended to confirm their monozygotic relationship. The first twins were term infants, and the twin 1A had a normal birth weight (2 500 g) while twin 1B was small for gestational age (2 450 g) . The other two pairs of twins were preterm, with different birth weights between twins 2 (2A is 2 450 g, 2B is 1 900 g) , but similar birth weights between twins 3. Although raised in the same environment, compared with twin 1A, 1B had obvious growth retardation. However, growth rate in the remaining twins were consistent. The renal abnormalities were not exactly the same between both twins 1 and twins 2, but was almost the same in twins 3. Both 1A and 1B were characterized by massive proteinuria and renal dysfunction, whereas 1B had worse renal function. At the last follow-up, 1A was diagnosed with stage 3 of chronic kidney disease (CKD) whereas 1B was CKD stage 4. Although renal function in twins 2 were normal, 2A had prominent proteinuria(24 h urinary total protein: 0.22 g) while 2B only had microalbuminuria(urinary albumin-to-creatinine ratio: 65 mg/g). Compared with the age-matched healthy controls, the concentration of uEGF normalized by urine creatinine (uEGF/Cr) were significantly lower in these twins. Besides, the twin-boy who had lower estimated glomerular filtration rates had lower uEGF/Cr. However, the extrarenal manifestations such as ocular and acoustic abnormalities were similar between the twins. Twins 2 and 3 showed bilateral temporal retinal thinning, and twins 1 both had binaural mild mid-low frequency sensorineural deafness. Conclusions: Renal manifestations of X-linked Alport syndrome in monozygotic twins may differ from each other, whereas the extrarenal manifestations including ocular and acoustic abnormalities may be consistent. Low birth weight and growth retardation may be associated with the progression of renal dysfunction.

[The therapeutic outcomes of ultrasound-guided percutaneous radiofrequency therapy for subcardiac liver malignant tumor].

Objective: To examine the safety and effectiveness of ultrasound-guided percutaneous radiofrequency ablation in the treatment of liver malignant tumor under subcardiac. Methods: The clinical data of 26 patients (31 tumors) with subcardiac liver malignant tumors who underwent ultrasound-guided percutaneous radiofrequency ablation from January 2017 to October 2019 at the Affiliated Tumor Hospital of Zhengzhou University were retrospectively analyzed. There were 21 males and 5 females. The age was 55 years old (range: 40 to 77 years old) .There were 14 cases of primary liver cancer and 12 cases of metastatic liver cancer. The maximum diameter of tumor was (2.3±1.0) cm (range: 1.0 to 4.2 cm) .According to the maximum diameter of the tumor, 1∶1 match was made between 27 non-subcardiac patients admitted at the same time and a total of 36 liver malignant tumors. subcardiac tumor is defined as tumor ≤1 cm from pericardium in sagittal or coronal imaging. The ablation effect and complications were recorded, and the one-time complete ablation rate, main technical efficiency and complications were evaluated. The preoperative baseline characteristics, ablation effect and complications of the two groups of patients were collected and counted. Single factor analysis and Logistic regression analysis were used to analyze the independent risk factors that affect the ablation effect of ultrasound-guided percutaneous radiofrequency ablation for liver malignant tumors under subcardiac. Results: The one-time complete ablation rate of tumor after radiofrequency ablation was 80.8% (21/26) in the subcardiac group and 92.6% (25/27) in the non-subcardiac group. There was no significant difference between the two groups (P>0.05) . No evidence of local tumor progression was found in the follow-up evaluation of the two groups one month after radiofrequency ablation, and the main technical effective rate was 100%.Ablation-related complications occurred in 2 patients in the subcardiac group. Multivariate analysis both showed that the distance between tumor margin and pericardium ≤5 mm was an independent risk factor affecting radiofrequency ablation (OR=0.020, 95%CI: 0.001 to 0.454, P=0.014) . Conclusions: Ultrasound-guided percutaneous radiofrequency ablation can safely and effectively treat liver malignant tumor under subcardiac. When there is a tumor near the patient's heart (the distance between the edge of the tumor and pericardium is ≤5 mm) , special attention should be paid to formulate a detailed and reasonable ablation plan to minimize tumor residue.

Operation of RF-driven negative hydrogen ion source in China Spallation Neutron Source.

The China Spallation Neutron Source started delivering neutron beams to users in March 2018. To upgrade the beam power to 500 kW and improve the performance of the ion source, an RF-driven negative hydrogen (H-) ion source is under development. The source has a silicon nitride ceramic plasma chamber surrounded by a 4.5-turn antenna. The plasma is ignited by a pulsed DC spark gap and then driven by a 2 MHz solid-state amplifier with a repetition rate of 25 Hz. The commissioning of the source started in January 2019. When uncesiated, it produced about 20 mA beam at an RF power of 32 kW and pulse width of 450 µs. This paper describes the configuration of the ion source, several peculiar technologies used in it, and the first negative hydrogen (H-) ion beam extraction.

Statin-treated patients with aneurysmal subarachnoid haemorrhage: a meta-analysis.

OBJECTIVE: The cerebral vasospasm, delayed ischemic neurological deficit (DIND), mortality and poor neurological outcome induced by aneurysmal subarachnoid haemorrhage (SAH) remain the major causes of morbidity and mortality in aneurysmal SAH patients. The effects of statin-treated for aneurysmal SAH patients were not comprehensively assessed. PATIENTS AND METHODS: A systematically literature search was conducted in PubMed, EMBASE, ScienceDirect and Web of Science to identify relevant studies update to March 2015. Data were extracted and appraised independently by two authors. Moreover, fixed or random effects models were applied to calculate pooled results based on the degree of heterogeneity. RESULT: Nine RCTs and three observational studies with a total of 1957 patients met the inclusion criteria. The results showed that statin treatment was not associated with a decrease in the occurrence of DIND (RR: 0.81, 95% CI: 0.66-1.00, p = 0.05), mortality (RR: 0.90, 95% CI: 0.69-1.18, p = 0.46) and poor neurological outcome (RR: 1.02, 95% CI: 0.86-1.20, p = 0.84), nonetheless, had a potential effect on reducing the incidence of vasospasm (RR: 0.77, 95% CI: 0.66-0.89, p = 0.0006). CONCLUSIONS: This meta-analysis indicated that the use of statins decreases the occurrence of cerebral vasospasm, whereas did not support a beneficial effect of statins on the occurrence of DIND, death or poor neurological outcomes in patients with aneurysmal SAH.

Cryopreservation of gemmae of Marchantia polymorpha L. (Marchantiophyta, Marchantiaceae) without prior pretreatment.

BACKGROUND: Successful cryopreservation of gametophytic material of bryophytes requires pretreatment with sucrose or abscisic acid. Compared to gametophyte materials, spore and gemmae cryopreservation may be more efficient, simple and stable systems for storing large amounts of genetic diversity of bryophytes within a small space. However, there has still been no attempt at cryopreserving bryophyte gemmae. OBJECTIVE: The aim of this study is to determine whether bryophyte gemmae with differing levels of desiccation tolerance could survive and germinate after cryopreservation without prior encapsulation and pretreatment. MATERIALS AND METHODS: Gemmae of Marchantia polymorpha L. were dried with silica gel for different times and then rapidly cooled in liquid nitrogen. RESULTS: The germination level of fresh gemmae was 95 % After 3 h predrying and 1 d in LN, germination was 68 % and was still up to 59 % after storage for 75 days. CONCLUSION: We conclude that the natural desiccation tolerance of bryophyte gemmae permits cryopreservation without prior pretreatment other than drying.

Association between HLA rs3129882 polymorphism and Parkinson's disease: a meta-analysis.

OBJECTIVE: As one of potential candidate genes for the risk of Parkinson's disease (PD), the HLA-DRA/PARK18 (rs3129882, A > G) gene has been studied extensively. However, direct evidence for the genetic association studies between PD and rs3129882 remains inconclusive. The aim of our meta-analysis was to determine a more reliable association between the rs3129882 and PD. MATERIALS AND METHODS: Comprehensive search strategy was used for electronic searches through PubMed, Elsevier, Springer Link, CNKI (Chinese National Knowledge Infrastructure) and WanFang (Chinese) databases to evaluate the association between rs3129882 and PD risk. Data were extracted and the odd ratios (ORs) and 95% confidence intervals (95% CIs) were calculated. Finally, we performed a meta-analysis of 13 appropriate papers by using a total of 11951 patients and 11902 controls. RESULTS: The meta-analysis showed no significant association between rs3129882 and PD risk in all four models (the allele model, dominant model, homozygote model and the recessive model). In allele model, the result was OR = 1.043 (95% CI = 0.978, 1.113). Moreover, this association remained no significant in the subgroup analysis stratified by ethnicity. CONCLUSIONS: In current meta-analysis, no significant association was found for rs3129882 and PD risk. And more well-designed primary researches will be needed to further evaluate the interaction of rs3129882 polymorphism and the susceptibility of PD.

Distortionless large-ratio stretcher for ultra-short pulses using photonic crystal fiber.

A large-ratio stretcher for ultra-short pulses is proposed based on photonic crystal fiber (PCF). Through proper design of the PCF structure, we obtain over 300-nm wavelength range with flattened dispersion characteristics. Analysis indicates that 1-km of such fiber can broaden over 10,000 times for ultra-short pulses with <100-fs pulse-width. Distortion due to dispersion and nonlinearity is negligible.

10 kD mitochondrial matrix heat shock protein mRNA is induced following global brain ischemia in the rat.

Heat shock proteins (HSP's) are a family of highly conserved proteins whose expression is increased by stress. The expression of many HSP's is induced in neurons by ischemia; however, the response of the 10 kDa mitochondrial matrix HSP (HSP10) is less well characterized. To address this issue, asphyxial cardiac arrest was induced in 28 male Sprague-Dawley rats. Northern blot analysis revealed that hsp10 mRNA was increased 2.7-fold in asphyxiated rats compared to sham-operated controls. In situ hybridization demonstrated increased mRNA in the cortex, septal nuclei, hippocampus, thalamic nuclei, purkinje cell layer of the cerebellum, and isolated brainstem nuclei of asphyxiated rats. The increase of mRNA was most robust 8 h after the injury but remained increased for 72 h. These results show that hsp10 mRNA is increased following asphyxial cardiac arrest in rats and suggest that hsp10 could be another determinate of neuronal survival after ischemia.

Cyclooxygenase-2 inhibition prevents delayed death of CA1 hippocampal neurons following global ischemia.

The inducible isoform of the enzyme cyclooxygenase-2 (COX2) is an immediate early gene induced by synaptic activity in the brain. COX2 activity is an important mediator of inflammation, but it is not known whether COX2 activity is pathogenic in brain. To study the role of COX2 activity in ischemic injury in brain, expression of COX2 mRNA and protein and the effect of treatment with a COX2 inhibitor on neuronal survival in a rat model of global ischemia were determined. Expression of both COX2 mRNA and protein was increased after ischemia in CA1 hippocampal neurons before their death. There was increased survival of CA1 neurons in rats treated with the COX2-selective inhibitor SC58125 [1-[(4-methylsulfonyl) phenyl]-3-trifluoro-methyl-5-[(4-fluoro)phenyl] pyrazole] before or after global ischemia compared with vehicle controls. Furthermore, hippocampal prostaglandin E2 concentrations 24 h after global ischemia were decreased in drug-treated animals compared with vehicle-treated controls. These results suggest that COX2 activity contributes to CA1 neuronal death after global ischemia.

Transient global ischemia triggers expression of the DNA damage-inducible gene GADD45 in the rat brain.

Using in situ hybridization, Northern blot analysis, Western blot analysis, and immunocytochemistry, mRNA and protein expression of the novel DNA damage-inducible gene GADD45 was examined in the rat brain at 0.5, 2, 4, 8, 16, 24, 48, and 72 hours after 15 minutes of transient global ischemia. Transient ischemia produced by the four-vessel occlusion method resulted in DNA double-strand breaks and delayed neuronal cell death in vulnerable neurons of the hippocampal CA1 sector, the hilus, dorsal caudate-putamen, and thalamus, as shown by in situ DNA nick end-labeling and histologic staining. GADD45 mRNA was transiently increased in less-vulnerable regions such as the parietal cortex (up to 8 hours after ischemia) and dentate granule cells (up to 24 hours after ischemia) but was persistently increased in vulnerable neurons such as CA1 pyramidal neurons (up to 48 hours). GADD45 immunoreactivity was increased in both vulnerable and less-vulnerable regions at earlier reperfusion periods (4 to 16 hours), but thereafter immunoreactivity was decreased below control levels in most vulnerable regions before delayed cell death and DNA double-strand breaks. At 72 hours after transient ischemia, a moderate increase in GADD45 immunoreactivity was still detectable in some CA3 neurons and in a few surviving neurons in the CA1 region. Double staining performed at 16 to 72 hours after ischemia revealed that GADD45 immunoreactivity was persistently increased in neurons that did not develop DNA damage. Because GADD45 protein may participate in the DNA excision repair process and because it has been shown that this protein is also overexpressed in neurons that survive focal ischemia and kainate-induced epileptic seizures, the results reported here support the hypothesis that GADD45 could have a protective role in neuronal injury.

Induction of caspase-3-like protease may mediate delayed neuronal death in the hippocampus after transient cerebral ischemia.

Delayed neuronal death after transient cerebral ischemia may be mediated, in part, by the induction of apoptosis-regulatory gene products. Caspase-3 is a newly characterized mammalian cysteine protease that promotes cell death during brain development, in neuronal cultures, and in other cell types under many different conditions. To determine whether caspase-3 serves to regulate neuronal death after cerebral ischemia, we have (1) cloned a cDNA encoding the rat brain caspase-3; (2) examined caspase-3 mRNA and protein expression in the brain using in situ hybridization, Northern and Western blot analyses, and double-labeled immunohistochemistry; (3) determined caspase-3-like activity in brain cell extracts; and (4) studied the effect of caspase-3 inhibition on cell survival and DNA fragmentation in the hippocampus in a rat model of transient global ischemia. At 8-72 hr after ischemia, caspase-3 mRNA and protein were induced in the hippocampus and caudate-putamen (CPu), accompanied by increased caspase-3-like protease activity. In the hippocampus, caspase-3 mRNA and protein were predominantly increased in degenerating CA1 pyramidal neurons. Proteolytic activation of the caspase-3 precursor was detected in hippocampus and CPu but not in cortex at 4-72 hr after ischemia. Double-label experiments detected DNA fragmentation in the majority of CA1 neurons and selective CPu neurons that overexpressed caspase-3. Furthermore, ventricular infusion of Z-DEVD-FMK, a caspase-3 inhibitor, decreased caspase-3 activity in the hippocampus and significantly reduced cell death and DNA fragmentation in the CA1 sector up to 7 d after ischemia. These data strongly suggest that caspase-3 activity contributes to delayed neuronal death after transient ischemia.

Belladonna alkaloids-induced behavioral changes and amnesia on open-field and step-through in 18-, 28-, and 38-day-old mice.

AIM: To study the age-related changes of atropine (Atr), scopolamine (Sco), anisodine (AT3), and anisodamine (Ani) on behaviors and memories. METHODS: The behaviors and memories were measured with open-field test and step-through task. M-cholinergic receptors were determined by [3H] quinuclidinyl benzilate ([3H] QNB). RESULTS: During acquisition session (d 1) the 18-, 28-, and 38-d-old mice pretreated with Atr, Sco, and AT3 (0.02, 0.2, 2, or 20 mg.kg-1, i.p.) in open-field test showed increase in walking counts by 26%-42%, but decrease in rearing, grooming, and defecating counts for 50%-92%, 67%-100%, and 75%-100%, respectively. On recall session (d 2) the walking and rearing behaviors in the 18- and 28-d-old mice receiving Atr, Sco, and AT3 on d 1 were higher than those in the mice receiving saline. But a lower grooming behavior on d 2 was found in the mice receiving the drugs on d 1. On d 1 Ani 20 mg.kg-1 reduced the rearing behavior by 50% in 18-d-old mice and defecation by 33%-36% in 18- and 28-d-old mice. All the 4 belladonna alkaloids increased the number of avoidance-response errors and decreased the retention latencies in step-through task. Bmax of [3H] QNB binding sites in frontal cortex and hippocampus regions in the 38-d-old mice increased 7% and 23% vs in the mice of 18 d of age, respectively. CONCLUSION: 1) The effects of the belladonna alkaloids on behaviors and memories in adult mice were weaker than those in young mice. 2) The belladonna alkaloids-induced amnesia on passive avoidance-response in step-through was more sensitive than behavioral changes and amnesia on open-field. 3) According to the lowest effective doses which insulted the behaviors or memories in young mice, Sco was about 10, 100, and 1000 times more potent than Atr, AT3, and Ani, respectively.

Kainate induces the expression of the DNA damage-inducible gene, GADD45, in the rat brain.

The expression of the novel growth arrest and DNA damage-inducible gene GADD45 was examined in kainate-induced epileptic brain damage in the rat using in situ hybridization, northern blot analysis, western blot analysis and immunocytochemistry. Systemic administration of kainate resulted in DNA damage and neuronal degeneration in vulnerable neurons of limbic regions, including the amygdala and hippocampal pyramidal layers, as shown by in situ DNA nick end-labelling and histological staining. GADD45 messenger RNA was transiently increased in non-vulnerable neurons (2-8 h after kainate injection) but was persistently elevated in vulnerable neurons (up to 24 h after injection) after kainate injection. GADD45 protein was elevated in both vulnerable and non-vulnerable neurons at 4 h, but levels decreased in vulnerable neurons thereafter, suggesting that translational blockage of GADD45 protein occurred in these cells. GADD45 protein was overexpressed in non-vulnerable neurons up to 72 h after kainate injection. Because GADD45 may participate in the DNA excision repair process and because it has been shown to be overexpressed in neurons that survive focal cerebral ischaemia, these results support the hypothesis that GADD45 may have a protective role in the injured brain.

Apoptosis repressor genes Bcl-2 and Bcl-x-long are expressed in the rat brain following global ischemia.

The proto-oncogenes bcl-2 and bcl-x-long have been shown to suppress apoptotic cell death in a variety of in vitro systems and cell lines, including neurons. An alternatively spliced from of bcl-x, bcl-x-short, is a promoter of apoptotic death. Whether these genes are induced after ischemia or play any role in determining the fate of ischemic neurons is unknown. To begin to address this issue, we studied the expression of bcl-2, and bcl-x mRNA and protein after global ischemia in the rat. Ischemia was induced in isoflurane-anesthetized rats by the four-vessel occlusion method. mRNA expression was studied by Northern blot analysis at 24 h after ischemia and by in situ hybridization at 2, 4, 8, 24, and 72 h after 15 min of global ischemia. Protein expression was studied using both immunocytochemistry at 4, 8, 16, 24, and 72 h after ischemia and Western blot analysis from tissue harvested at 16, 24, and 72 h after ischemia. Western blots showed that bcl-x-long is the predominant form of bcl-x protein expressed in both normal and ischemic brain. Both bcl-2 and bcl-x-long mRNA were expressed in CA1, CA3, and the molecular layer of the dentate after ischemia. However, bcl-2 and bcl-x protein were expressed only in CA3 and dentate. Thus, while bcl-2 and bcl-x-long mRNA were expressed in both surviving and dying neurons, their proteins were expressed in neurons destined to survive. These results support potential roles for these two apoptosis suppressor proteins in promoting survival after cerebral ischemia.

Expression of the apoptosis-effector gene, Bax, is up-regulated in vulnerable hippocampal CA1 neurons following global ischemia.

The observation that delayed death of CA1 neurons after global ischemia is inhibited by protein synthesis inhibitors suggests that the delayed death of these neurons is an active process that requires new gene expression. Delayed death in CA1 has some of the characteristics of apoptotic death; however, candidate proapoptotic proteins have not been identified in the CA1 after ischemia. We studied the expression of Bax protein and mRNA, a member of the bcl-2 family that is an effector of apoptotic cell death, after global ischemia in the four-vessel global ischemia model in the rat and compared these results with the expression of the antiapoptotic gene bcl-2. Bax mRNA and protein are both expressed in CA1 before delayed death, whereas bcl-2 protein is not expressed. Bcl-2 protein expression, but not that of Bax, is increased in CA3, a region that is ischemic but less susceptible to ischemic injury. In the dentate gyrus, both Bax and bcl-2 proteins are expressed. The selective expression of Bax in Ca1 supports the hypothesis that Bax could contribute to delayed neuronal death in these vulnerable neurons by an independent mechanism or by forming heterodimers with gene family members other than bcl-2.

Focal ischemia induces expression of the DNA damage-inducible gene GADD45 in the rat brain.

GADD45 is a DNA damage-inducible gene that accelerates DNA excision repair and can be induced by a variety of DNA-damaging stimuli in mammalian cells. We investigated the expression of GADD45 mRNA and protein using in situ hybridization and immunocytochemistry in rat brains after 2 h of temporal focal ischemia. The expression of GADD45 mRNA was induced in neurons throughout ischemic cortex 4 h after the onset of ischemia but was restricted to ischemic penumbra regions at 24 h after ischemia. The expression of GADD45 protein was increased only in sublethally injured neurons in the penumbra regions at both 4 h and 24 h following ischemia. These results suggest that GADD45 could have a protective role in ischemic neurons.