Timed sulfonylurea modulation improves locomotor and sensory dysfunction following spinal cord injury.

Traumatic spinal cord injury (SCI) results in immediate tissue necrosis and delayed secondary expansion of neurological damage, often resulting in lifelong paralysis, neurosensory dysfunction, and chronic pain. Progressive hemorrhagic necrosis (PHN) and excessive excitation are the main sources of secondary neural injury. Recent approaches to attenuate PHN by glibenclamide can improve locomotor function after SCI. However, use of glibenclamide can exacerbate development of SCI-induced chronic pain by inhibiting KATP channels to increase neuronal excitation and glial activation. In this study, we explored a treatment strategy involving administration of glibenclamide, which suppresses PHN, and diazoxide, which protects against neuronal excitation and inflammation, at different time intervals following spinal cord contusion. Our goal was to determine whether this combined approach enhances both sensory and motor function. Contusive SCI was induced at spinal segment T10 in adult rats. We found that KATP channels opener, diazoxide, decreased the hyperexcitability of primary sensory neurons after SCI by electrophysiology. Timed application of glibenclamide and diazoxide following contusion significantly improved locomotor function and mitigated development of SCI-induced chronic pain, as shown by behavioral evidence. Finally, we found that timed application of glibenclamide and diazoxide attenuates the inflammatory activity in the spinal cord and increases the survival of spinal matters following SCI. These preclinical studies introduce a promising potential treatment strategy to address SCI-induced dysfunction.

Corrigendum: Case report: Potential predictive value of MMR/MSI status and PD-1 expression in immunotherapy for urothelial carcinoma.

[This corrects the article DOI: 10.3389/pore.2022.1610638.].

Case Report: Potential Predictive Value of MMR/MSI Status and PD-1 Expression in Immunotherapy for Urothelial Carcinoma.

Immune checkpoint inhibitors (ICIs) have shown encouraging outcomes against Lynch syndrome (LS)-associated colorectal cancer (CRC) and endometrial cancer with mismatch repair deficient/microsatellite instability-high (dMMR/MSI-H). However, there is as yet no clarity on the safety and efficacy of immunotherapy combined with chemotherapy in LS-associated urothelial carcinoma (UC). Here, we report a patient with recurrent and metastatic LS-associated UC who achieved sustained response to programmed death protein 1 (PD-1) inhibitor combined with chemotherapy over 31 months, during which the side effects of immunotherapy could be controlled and managed. Our findings indicate that the dMMR/MSI status and PD-1 expression in UC may have potential predictive value for the response to PD-1-targeted immunotherapy. Our case supports the inclusion of such combination and/or monotherapy for UC in clinical studies and using dMMR/MSI status and PD-1 expression as potential predictive biomarkers for assessment of the therapeutic response.

Association of Caveolin-1 Expression With Prostate Cancer: A Systematic Review and Meta-Analysis.

PURPOSE: The prognostic value of caveolin-1 in prostate cancer remains uncertain. Hence, this meta-analysis was performed to evaluate the prognostic value of caveolin-1 in prostate cancer, as well as ascertain the relationship between caveolin-1 expression and clinicopathological characteristics of prostate cancer patients. METHODS: The PubMed, Embase, Chinese National Knowledge Infrastructure and Chinese Biology Medicine databases were electronically searched to retrieve published studies on caveolin-1 expression in prostate cancer. After study selection and data extraction, the meta-analysis was conducted using Review manager 5.3 software. Odds ratio (OR) with 95% confidence interval (CI) was used to estimate the pooled effect. Funnel plot was used to assess publication bias. RESULTS: A total of ten studies were enrolled, which included 3976 cases of prostate cancer, 72 cases of high-grade intraepithelial neoplasia (HGPIN), and 157 normal controls. Results of the meta-analysis showed that the positive rate of caveolin-1 expression in prostate cancer was 18.28 times higher than that in normal control (OR= 18.28, 95% CI: 9.02-37.04, p<0.01), and 4.73 times higher than that in HGPIN (OR= 4.73, 95% CI: 2.38-9.42, p<0.01). The relationship between caveolin-1 and clinicopathological characteristics of prostate cancer showed that the differences in caveolin-1 expression in patients with prostate-specific antigen (PSA) >10 vs. ≤ 10 (OR=2.09, 95% CI: 1.35-3.22, p<0.01), differentiation degree low vs. medium/high (OR=2.74, 95% CI: 1.84-4.08, p<0.01), TNM stage T3+T4 vs. T1+T2 (OR=2.77, 95% CI: 1.78-4.29, p<0.01), and lymph node metastasis present vs. absent (OR=2.61, 95% CI: 1.84-3.69, p<0.01) were statistically significant. The correlation analysis between caveolin-1 and the survival time of patients with prostate cancer demonstrated that caveolin-1 was closely related to the prognosis of prostate cancer patients (HR=1.50, 95% CI: 1.28-1.76, p<0.01). CONCLUSION: Caveolin-1 is overexpressed in prostate cancer, which can serve as a risk factor and adverse clinicopathological feature of prostate cancer. Caveolin-1 can also predict poor survival in prostate cancer patients after radical prostatectomy.

[Investigation and genetic identification on Babesia infection in rodents in some areas of Fujian Province].

Objective: To explore the status of Babesia infection in rodents and the genetic characteristics of Babesia spp. in Fujian Province. Methods: Rodents were captured by the night trapping method in Shaowu, Qingliu, Shunchang, Yong'an, Changle and Youxi during 2014-2015. The rodent species was identified, and information on the time and place of capture, species and sex of rodents was recorded. Blood samples was collected, in which the fragment of 18S rRNA gene of Babesia spp. was amplified by PCR. The PCR products were sequenced and the phylogenetic tree was constructed for homology analysis. Data on positive rate were analyzed with Chi-square or Fisher exact test. Results: Two hundred and nine rats were captured, comprising of 71 domestic and 138 wild rats. The overall positive rate was 9.6%(20/209). The positive rate in domestic rats was 2.8%(2/71), including one Rattus norvebicus and one Rattus flavipectus. The positive rate in wild rats was 13.0%(18/138), including 13 Bandicota indica, one Rattus losea, 2 Rattus confucianus and 2 Rattus fulvescens. The positive rate was significantly higher in wild rats than in domestic rats (P < 0.05). The Youxi region had the highest positive rate(14.9%,13/87), followed by Yong'an(13.6%, 3/22), and no positive rat was found in Qingliu. The positive rate in the male rats was 7.9%(9/114), and that in the females was 11.6%(11/95). The positive rate was highest in adult rats (10.4%,18/173), followed by young ones (6.3%,2/32). No positive rat was found in old rats. There was no significant difference in positive rate among different regions, between male and female rats, or among different ages (P > 0.05). The sequences of PCR products had a 100% homology. The BLAST results revealed the species to be Babesia microti. The phylogenetic tree showed that the sample sequence was the most homologous with Babesia microti from Zhejiang Province(GenBank Accession No: JQ609305). Conclusion: There occurs Babesia microti infection in rats in part areas of Fujian Province. The positive rate was higher in wild rats than in domestic rats.

Two new flavonoids from the roots of Scutellaria baicalensis.

One new flavone, 5,7-dihydroxy-8,2',3',6'-tetramethoxyflavone (1), and one new flavonol, 5,7,6'-trihydroxy-2'-methoxyflavonol (2), were isolated from the roots of Scutellaria baicalensis, and their structures were elucidated on the basis of extensive spectroscopic evidences, especially 1D and 2D NMR and HR-ESI-MS experiments. The structure features of these new compounds lie in the substitution at both C-2' and C-6' positions of B-ring by hydroxyl or methoxyl groups.

Changes of c-fos, malondialdehyde and lactate in brain tissue after global cerebral ischemia under different brain temperatures.

Under global cerebral ischemia, the effect of different brain temperature on cerebral ischemic injury was studied. Male Sprague-Dawley rats were divided into normothermic (37-38°C) ischemia, mild hypothermic (31-32°C) ischemia, hyperthermic (41-42°C) ischemia and sham-operated groups. Global cerebral ischemia was established using the Pulsinelli four-vessel occlusion model and brain temperature was maintained at defined level for 60 min after 20-min ischemia. The expression of c-fos protein and the levels of malondialdehyde (MDA) and lactate in brain regions were detected by immunochemistry and spectrophotometrical methods, respectively. C-fos positive neurons were found in the hippocampus and cerebral cortex after cerebral ischemia reperfusion. Mild hypothermia increased the expression of c-fos protein in both areas, whereas hyperthermia decreased the expression of c-fos protein in the hippocampus at 24 h reperfusion, and the cerebral cortex at 48 h reperfusion when compared to normothermic conditions. In normothermic, mild hypothermic and hyperthermic ischemia groups, the levels of MDA and lactate in brain tissue were increased at 24, 48 and 72 h reperfusion following 20-min ischemia as compared with the sham-operated group (P<0.01). The levels of MDA and lactate in mild hypothermic group were significantly lower than those in normothermic group (P<0.01). It is suggested that brain temperature influences the translation of the immunoreactive protein product of c-fos after global cerebral ischemia, and MDA and lactate are also affected by hypothermia and hyperthermia.

Calcium/calmodulin dependent kinase II contributes to persistent central neuropathic pain following spinal cord injury.

Chronic central neuropathic pain after central nervous system injuries remains refractory to therapeutic interventions. A novel approach would be to target key intracellular signaling proteins that are known to contribute to continued activation by phosphorylation of kinases, transcription factors, and/or receptors that contribute to changes in membrane excitability. We demonstrate that one signaling kinase, calcium/calmodulin-dependent kinase II (CaMKII), is critical in maintaining aberrant dorsal horn neuron hyperexcitability in the neuropathic pain condition after spinal cord injury (SCI). After contusion SCI at spinal level T10, activated CaMKII (phosphorylated, pCaMKII) expression is significantly upregulated in the T7/8 spinal dorsal horn in neurons, but not glial cells, and in oligodendrocytes in the dorsal column in the same rats that displayed at-level mechanical allodynia. Furthermore, identified spinothalamic neurons demonstrated significant increases of pCaMKII after SCI compared to sham-treated control animals. However, neither astrocytes nor microglia showed pCaMKII expression in either sham-treated or SCI rats. To demonstrate causality, treatment of SCI rats with KN-93, which prevents CaMKII activation, significantly attenuated at-level mechanical allodynia and aberrant wide dynamic range neuronal activity evoked by brush, pressure, and pinch stimuli and a graded series of von Frey stimuli, respectively. Persistent CaMKII activation contributes to chronic central neuropathic pain by mechanisms that involve maintained hyperexcitability of wide dynamic range dorsal horn neurons. Furthermore, targeting key signaling proteins is a novel, useful therapeutic strategy for treating chronic central neuropathic pain.

Physiological effects of androgens on human vascular endothelial and smooth muscle cells in culture.

Androgenic hormones are associated with atherosclerotic cardiovascular disease, although the underlying cellular and molecular mechanisms remain unclear. This study examines the impact of androgens on the physiology of human vascular endothelial cells (EC) and smooth muscle cells (SMC) in culture. Cells were incubated with testosterone, dihydrotestosterone (DHT) or dehydroepiandrosterone (DHEA) at various physiological concentrations (5-50 nM) in the present or absence of an androgen receptor (AR) blocker flutamide (100 nM). Cell growth and death, DNA and collagen synthesis, and gene protein expression were assessed. It was shown that: (1) DHEA protected EC from superoxide injury via AR-independent mechanisms; (2) testosterone induced DNA synthesis and growth in EC via an AR-independent manner with activation of ERK1/2 activity; (3) DHT inhibited DNA synthesis and growth in EC in an AR-dependent manner; (4) testosterone and DHT enhanced ERK1/2 activation and proliferation in SMC via AR-independent and -dependent pathways, respectively; and (5) these androgens did not significantly affect collagen synthesis in SMC. We conclude that androgens possess multiple effects on vascular cells via either AR-dependent or -independent mechanisms. Testosterone and DHEA may be "beneficial" in preventing atherosclerosis by improving EC growth and survival; in contrast, stimulation of VSMC proliferation by testosterone and DHT is potentially "harmful". The relationship of these in vitro effects by androgens to in vivo vascular function and atherogenesis needs to be further clarified.

[Activation of tumor necrosis factor receptor-associated factor 6 in anti-ß2GPI/ß2GPI-induced tissue factor expression on THP-1 cells].

AIM: To investigate whether tumor necrosis factor receptor-associated factor 6 (TRAF6) is involved in anti-ß2GPI/ß2GPI-induced tissue factor (TF) expression on THP-1 cells. METHODS: The total RNA was extracted and the protein lysates were collected from THP-1 cells stimulated with anti-ß2GPI/ß2GPI complex. And then the TF expression on THP-1 cells was detected by real-time quatitative PCR (RT-qPCR) and TF activity kit. TRAF6 mRNA and its protein expression were investigated by RT-qPCR and Western blotting, respectively. The proteasome inhibitor, MG-132, was used for inhibitory assays, in order to demonstrate the effect of anti-ß2GPI/ß2GPI complex on THP-1 cells. RESULTS: The TF expression (both mRNA and activity) on THP-1 cells was significantly up-regulated with the treatment of anti-ß2GPI/ß2GPI complex (100 mg/L), compared with untreated cells(P<0.05). The TRAF6 mRNA and protein levels in THP-1 cells were also significantly increased with the treatment of anti-ß2GPI/ß2GPI complex. The expression of TRAF6 was shown in a time-dependent manner, with the maximal level at 15 minutes (mRNA) and 30 minutes (protein) respectively. All the stimulating effects of anti-ß2GPI/ß2GPI complex (100 mg/L) on THP-1 cells were inhibited by MG-132 (5 µmol/L). CONCLUSION: TRAF6 is up-regulated and contributes to TF expression on THP-1 cells induced with anti-ß2GPI/ß2GPI complex.

[Role of NF-κB in factor VIIa-induced proliferation and migration of colon cancer cell line SW620 cells].

OBJECTIVE: To explore the roles of NF-κB in factor VIIa-induced proliferation and migration of a colon cancer cell line (SW620) in vitro and its possible mechanism. METHODS: The expression levels of NF-κB (p65), inhibitory protein of NF-κB (IκB-α), caspase-7, interleukin 8 (IL-8) and tissue factor (TF) in SW620 cells treated with factor VIIa, PDTC (an inhibitor of NF-κB) and other factors were measured by Western-blotting and real-time PCR. Proliferation and migration of the cells were analyzed by flow cytometry and Transwell assay, respectively. RESULTS: Factor VIIa down-regulated the IκB-α level in SW620 cells and increased the intranuclear level of NF-κB. Those effects of factor VIIa were blocked by anti-TF or anti-PAR2 antibodies. The effects of factor VIIa on proliferation and migration of SW620 cells, expression of IL-8, TF as well as caspase-7, were interfered by PDTC (the inhibitor of NF-κB). CONCLUSIONS: TF/VIIa complex activates NF-κB pathway via PAR2, thereby up-regulates IL-8 and down-regulates caspase-7 expression in SW620 cells, finally promotes proliferation and migration of colon cancer cells. In addition, TF/VIIa/PAR2/NF-κB pathway also upregulates TF expression, thus to create a positive feedback loop of TF/VIIa/PAR2/NF-κB/TF.

Regulation of interleukin-1beta by the interleukin-1 receptor antagonist in the glutamate-injured spinal cord: endogenous neuroprotection.

Elevation of extracellular glutamate contributes to cell death and functional impairments generated by spinal cord injury (SCI), in part through the activation of the neurotoxic cytokine interleukin-1beta (IL-1beta). This study examines the participation of IL-1beta and its regulation by the endogenous interleukin-1 receptor antagonist (IL-1ra) in glutamate toxicity following SCI. Glutamate, glutamatergic agonists and SCI had similar effects on levels of IL-1beta and IL-1ra. Following spinal cord contusion or exposure to elevated glutamate, concentrations of IL-1beta first increased as IL-1ra decreased, and both then changed in the opposite directions. Applying the glutamate agonists NMDA and S-AMPA to the spinal cord caused changes in IL-1beta and IL-1ra levels very similar to those produced by contusion and glutamate. The glutamate antagonists MK801 and NBQX blocked the glutamate-induced changes in IL-1beta and IL-1ra levels. Administering IL-1beta elevated IL-1ra, and administering IL-1ra depressed IL-1beta levels. Infusing IL-beta into the spinal cord impaired locomotion, and infusing IL-1ra improved recovery from glutamate-induced motor impairments. We hypothesize that elevating IL-1ra opposes the damage caused by IL-1beta in SCI by reducing IL-1beta levels as well as by blocking binding of IL-1beta to its receptor. Our results demonstrate that IL-1beta contributes to glutamate damage following SCI; blocking IL-1beta may usefully counteract glutamate toxicity.

[Application of purified recombinant outer membrane lipoprotein LipL32 in detecting antibodies among leptospirosis cases].

OBJECTIVE: To establish recombinant outer membrane lipoprotein LipL32-based antibody detection assays in identifying leptospirosis. METHODS: Recombinant leptospiral outer membrane protein LipL32 was obtained by genetic engineering method. This purified protein was used in the indirect and sandwich ELISA assays to test the antibodies in sera of human beings and rats, and the results were compared with those obtained by microscopy agglutination test (MAT) and imported ELISA kit. RESULTS: When the acute and convalescent phase specimens from 9 leptospiral patients were tested, the detected rates of three ELISAs were similar to the MAT. Among the 45 probable cases which MAT showed positive, 32 (71.11%) samples were positive by r32-I-ELISA, 36 (80.00%) by r32-S-ELISA, while 28.89% (13/45) samples were positive and 55.56% (25/45) were suspicious by D.A.I-ELISA. The specificity of r32-I-ELISA and r32-S-ELISA were 97.10% (67/69) for 69 specimens. 43 healthy specimens were negative by both r32-I-ELISA and r32-S-ELISA, 14 healthy specimens were negative by D.A.I-ELISA. Among 16 non-leptospirosis patients, two specimens were positive by r32-I-ELISA and r32-S-ELISA, D.A.I-ELISA and identified one positive specimen, while 12 specimens were suspicious by D.A.I-ELISA. For 10 syphilis specimens, data obtained through three ELISAs were in consistent with that by MAT. A sandwiched ELISA, using rLipL32 protein as the antigen was developed to detect rat sera. Considering MAT as standard test, the sensitivity and specificity were 86.75% (131/151), 99.19% (122/123) respectively with coincidence rate as 92.34% (253/274). CONCLUSION: The recombinant protein LipL32 had high immunoreactivity and could be used as an antigen for the detection of pathogenic leptospirosis. In summary, the novel sandwiched ELISA with rLipL32 showed similar sensitivity and specificity to that of MAT in the antibody detection of rat leptospirosis. It was suitable for large scales field sero-epidemiological studies.

[Effect of atorvastatin on carotid intima-medial of thickness of primary hypertension patients of Han nationality in China].

OBJECTIVES: To investigate the efficacy of 10 mg or 20 mg atorvastatin + long acting antihypertensive in carotid intima-medial thickness (IMT). METHODS: 151 patients of Han nationality in South China with mild hypertensive were randomly divided into 3 groups: atorvastatin 10 mg group (n = 50) receive 10 mg atorvastatin and amlodipine + benazepril; atorvastatin 20 mg group (n = 61) receive 20 mg atorvastatin and amlodipine + benazepril; the control group (n = 40) receive amlodipine + benazepril. The patients were detected IMT, vascular function, lipids and inflammatory factor in pretherapy and every 3 months. RESULTS: atorvastatin 10 mg or 20 mg groups have significantly change contrast to control group: (1) IMT was decreased (P < 0.01). (2) Deltadia-P% and Deltadia-N% were increased (P < 0.01). (3) LDL-C level was decreased by 30% in a atorvastatin 10 mg group and 40.48% in 20 mg group respectively (P < 0.01). CONCLUSION: Atorvastatin delays the development of atherosclerosis in hypertensive patients, improves endothelial function, and strengthens the effect of lipid-lowering.

Serum albumin improves recovery from spinal cord injury.

A neuroprotective factor is shown to be present in mammalian serum. This factor is identified by Western blotting to be serum albumin. The serum factor and albumin both protected cultured spinal cord neurons against the toxicity of glutamate. The inability of K252a, a blocker of the high affinity tyrosine kinase receptor for members of the nerve growth factor family, to block the neuroprotective effect of the serum factor established that the serum factor is not a member of the nerve growth factor family. Post-injury injection of albumin intravenously or into the site of injury immediately after injury both improved significantly locomotor function according to Basso-Beattie-Bresnahan assessment and spontaneous locomotor activity recorded with a photobeam activity system. Albumin has multiple mechanisms whereby it may be neuroprotective, and it is a potentially useful agent for treating neurotraumas.

Increases in the activated forms of ERK 1/2, p38 MAPK, and CREB are correlated with the expression of at-level mechanical allodynia following spinal cord injury.

Rats given moderate spinal cord injury (SCI) display increases in the expression of the activated form of the transcription factor cyclic AMP responsive element binding protein (CREB) in spinal segments of dermatomes corresponding to permanent mechanical allodynia, a model of chronic central neuropathic pain (CNP; (Crown, E.D., Ye, Z., Johnson, K.M., Xu, G.Y., McAdoo, D.J., Westlund, K.N., Hulsebosch, C.E., 2005. Upregulation of the phosphorylated form of CREB in spinothalamic tract cells following spinal cord injury: relation to central neuropathic pain. Neurosci. Lett. 384, 139-144)). Given that not all rats that receive moderate SCI develop CNP, the current study was designed to further analyze changes in persistent CREB activation and in the activation state of upstream intracellular signaling cascades (e.g., mitogen-activated protein kinases [MAPKs]) in populations of rats that receive SCI and weeks later develop CNP and rats that receive SCI but do not develop CNP. The results indicate that activated kinases such as pERK 1/2, p-p38 MAPK, but not pJNK, are upregulated in injured rats that develop CNP as compared to injured rats that fail to develop CNP. In addition, the current results replicated our previous finding that activated CREB is upregulated following SCI, however, only in SCI rats that developed CNP. Taken together, these results indicate that activation of intracellular signaling cascades traditionally associated with long-term potentiation and memory is associated with the expression of chronic CNP following SCI.

Transcriptional profiling of spinal cord injury-induced central neuropathic pain.

Central neuropathic pain (CNP) is an important problem following spinal cord injury (SCI), because it severely affects the quality of life of SCI patients. As in the patient population, the majority of rats develop significant allodynia (CNP rats) after moderate SCI. However, about 10% of SCI rats do not develop allodynia, or develop significantly less allodynia than CNP rats (non-CNP rats). To identify transcriptional changes underlying CNP development after SCI, we used Affymetrix DNA microarrays and RNAs extracted from the spinal cords of CNP and non-CNP rats. DNA microarry analysis showed significantly increased expression of a number of genes associated with inflammation and astrocytic activation in the spinal cords of rats that developed CNP. For example, mRNA levels of glial fibrilary acidic protein (GFAP) and Aquaporin 4 (AQP4) significantly increased in CNP rats. We also found that GFAP, S100beta and AQP4 protein elevation persisted for at least 9 months throughout contused spinal cords, consistent with the chronic nature of CNP. Thus, we hypothesize that CNP development results, in part, from dysfunctional, chronically "over-activated" astrocytes. Although, it has been shown that activated astrocytes are associated with peripheral neuropathic pain, this has not previously been demonstrated in CNP after SCI.

Administration of glutamate into the spinal cord at extracellular concentrations reached post-injury causes functional impairments.

In vivo experiments addressing the role of released glutamate in damage caused by neurotrauma seldom administer glutamate itself because it usually produces relatively little damage when administered into central nervous system (CNS) tissue in vivo. However, because of recent observations that glutamate administered into the spinal cord at the levels attained following spinal cord injury (SCI) kills neurons and oligodendrocytes, we tested the effects of administering glutamate at those concentrations on locomotor function. The Basso-Beattie-Bresnahan (BBB) test and activity box measures demonstrated that those glutamate concentrations produce lasting functional impairments. Several parameters provided by the activity box provided sensitive measures of the degree of post-SCI impairment, demonstrating their substantial potential for evaluating outcomes of SCI. Results obtained also enhance evidence that glutamate toxicity contributes to secondary damage following SCI and suggest that damage to white matter is an important contributor to such damage.

[Evaluation of steal phenomena by measuring the steal index using transcranial Doppler ultrasound in intracranial arteriovenous malformation].

OBJECTIVE: The authors previously deduced a formula for calculating the steal index (SI) for evaluation of the steal phenomena during the development of the collateral circulation resulting from unilateral carotid artery occlusion or stenosis. In this study the authors examine the application of SI in evaluating the steal phenomena of cerebral blood flow in cases of intracranial arteriovenous malformation (AVM). METHODS: The clinical data of 16 cases of AVM confirmed by both digital subtraction angiography (DSA) and transcranial Doppler (TCD) ultrasound were analyzed retrospectively. The ratio of the mean blood velocity in the direct or indirect feeding artery (Vmfv) for the area containing AVM to the mean blood velocity in the neighboring feeding artery (Vmna), Vmfv/Vmna, was compared with SI of the corresponding arteries (SI=1-PI(1)/PI(2), where PI(1) is the pulsatility index of the feeding artery and PI the pulsatility index of the neighboring feeding artery), and the correlation between SI and the size of AVM was analyzed statistically. RESULTS: The Vmfv/Vmna of (2)direct and indirect feeding arteries for AVM both exhibited positive correlation with SI (r=0.62, P<0.05, n=16; r=0.53, P<0.01, n=27), and SI appeared to be in positive correlation with the size of AVM, but which failed to be supported by statistical analysis (r=0.48, P>0.05, n=12). CONCLUSION: The sizes, types and development of the vascular bed of AVM can be evaluatea by analysis of SI derived from TCD in combination with DSA.

Concentrations of glutamate released following spinal cord injury kill oligodendrocytes in the spinal cord.

We investigated in vivo in rats whether sufficient glutamate is released following spinal cord injury (SCI) to kill oligodendrocytes. Microdialysis sampling was used to establish the level of glutamate released (550 +/- 80 microM) in the white matter during SCI. This glutamate concentration was administered into the spinal cords of other rats and the densities of oligodendrocytes remaining 24 and 72 h later determined by counting cells immunostained with the oligodendrocyte marker CC-1. Administration of ACSF, 4.0 mM glutamate (estimated resulting tissue exposure 500 microM) and 10.0 mM glutamate by microdialysis reduced oligodendrocyte density 22%, 57%, and 74%, respectively, relative to normal at 24 h post-exposure. Therefore, sufficient glutamate is released following SCI to damage white matter. Oligodendrocyte densities near the fiber track were not significantly different at 72 h from 24 h post-exposure, so most glutamate-induced oligodendrocyte death occurs within 24 h after exposure. Injecting the AMPA/kainate receptor blocker NBQX into the spinal cord during glutamate administration reduced the glutamate-induced decrease in oligodendrocyte density, evidence for AMPA/kainate receptor involvement in glutamate-induced oligodendrocyte death. This work directly demonstrates in vivo that following SCI glutamate reaches concentrations toxic to white matter and that AMPA/kainate receptors mediate this glutamate toxicity to oligodendrocytes.