Role of tumour location and surgical extent on prognosis in T2 gallbladder cancer: an international multicentre study

BACKGROUND

In gallbladder cancer, stage T2 is subdivided by tumour location into lesions on the peritoneal side (T2a) or hepatic side (T2b). For tumours on the peritoneal side (T2a), it has been suggested that liver resection may be omitted without compromising the prognosis. However, data to validate this argument are lacking. This study aimed to investigate the prognostic value of tumour location in T2 gallbladder cancer, and to clarify the adequate extent of surgical resection.

METHODS

Clinical data from patients who underwent surgery for gallbladder cancer were collected from 14 hospitals in Korea, Japan, Chile and the USA. Survival and risk factor analyses were conducted.

RESULTS

Data from 937 patients were available for evaluation. The overall 5-year disease-free survival rate was 70·6 per cent, 74·5 per cent for those with T2a and 65·5 per cent among those with T2b tumours (P = 0·028). Regarding liver resection, extended cholecystectomy was associated with a better 5-year disease-free survival rate than simple cholecystectomy (73·0 versus 61·5 per cent; P = 0·012). The 5-year disease-free survival rate was marginally better for extended than simple cholecystectomy in both T2a (76·5 versus 66·1 per cent; P = 0·094) and T2b (68·2 versus 56·2 per cent; P = 0·084) disease. Five-year disease-free survival rates were similar for extended cholecystectomies including liver wedge resection versus segment IVb/V segmentectomy (74·1 versus 71·5 per cent; P = 0·720). In multivariable analysis, independent risk factors for recurrence were presence of symptoms (hazard ratio (HR) 1·52; P = 0·002), R1 resection (HR 1·96; P = 0·004) and N1/N2 status (N1: HR 3·40, P < 0·001; N2: HR 9·56, P < 0·001). Among recurrences, 70·8 per cent were metastatic.

CONCLUSION

Tumour location was not an independent prognostic factor in T2 gallbladder cancer. Extended cholecystectomy was marginally superior to simple cholecystectomy. A radical operation should include liver resection and adequate node dissection.

Accident prevention activity and accident experience in the Republic of Korea military

Introduction

According to data released by the Korea National Statistical Office, the number of accidents has been decreasing since 2012. However, a considerable number of deaths related to safety accidents (23–46 deaths) are still reported annually. This study aimed to observe the correlation between accident prevention activities in the Republic of Korea (ROK) military and the incidence of safety accidents.

Methods

The study used data from the 2014–2015 Military Health Survey and included 13 618 responses (Army: 8414 (61.8%); Navy/Marine: 2262 (16.6%); Air Force: 2942 (21.6%)) from the ROK military personnel. Accident experiences and thoughts on accident prevention activities were self-reported. Multiple logistic regression analysis was used to examine the validity of accident prevention activity and accident experience.

Results

Of the 13 618 military personnel who responded, 12.0% reported experiencing safety accidents in the military and 1020 (7.5%) felt that accident prevention activities in the military were insufficient. On logistic regression analysis, we found a significant difference (insufficiency OR=1.56, CI 1.31 to 1.86). In particular, military personnel who belong to the Army and Navy were more likely to think that accident prevention activities were insufficient. In addition, military personnel who experienced falls/slips, crash, and laceration/puncture wound/amputation/penetrating wound accidents were more likely to think accident prevention activities were insufficient.

Conclusions

Our study found that accident prevention activities in the military and accident experiences were related. It is necessary for the ROK Ministry of Defense, Army, Navy and Air Force headquarters to re-evaluate their accident prevention systems.

Effect of hypothermia treatment on gentamicin pharmacokinetics in neonates with hypoxic-ischaemic encephalopathy: A systematic review and meta-analysis

WHAT IS KNOWN AND OBJECTIVE

Hypothermia is the current standard therapy for asphyxiated neonates with hypoxic-ischaemic encephalopathy (HIE). Gentamicin is used for the empirical treatment of early-onset neonatal sepsis. We investigated the influence of hypothermia treatment on gentamicin pharmacokinetics and suggested the appropriate dosing recommendations for gentamicin in neonates with HIE receiving hypothermia treatment.

METHODS

We searched studies published until February 2017 in MEDLINE using PubMed, EMBASE and the Cochrane Library. Three independent reviewers screened the literature and extracted data from each study. All of the studies that reported the blood concentrations or pharmacokinetic parameters of gentamicin in hypothermic neonates with HIE were included in this review. Articles were excluded if they were not original research.

RESULT AND DISCUSSION

A total of 8 observational studies met the inclusion criteria. Meta-analyses were performed in which the mean difference of gentamicin for the trough concentration and clearance between hypothermic and normothermic neonates were 0.81 mg/L (95% confidence interval [-0.07, 1.69]) and -0.21 mL/kg/min (95% confidence interval [-0.31, -0.12]), respectively. The factors affecting gentamicin clearance in hypothermic neonates with HIE were gestational age, birthweight and serum creatinine.

WHAT IS NEW AND CONCLUSION

Gentamicin clearance is decreased in neonates with HIE receiving hypothermia treatment compared to those not receiving hypothermia treatment. Modified gentamicin dosing regimens are required to avoid potential toxicity related to higher concentrations during hypothermia treatment.

Surgical treatment of solid pseudopapillary neoplasms of the pancreas and risk factors for malignancy

BACKGROUND

The aim of this study was to identify clinical predictors of malignancy and surgical strategies for pancreatic solid pseudopapillary neoplasm (SPN) by analysis of surgical outcomes at a single institution.

METHODS

All patients who underwent surgery for SPN between 1995 and 2010 were identified. Histopathology slides of all patients were reviewed by a specialized pathologist and the neoplasms were classified according to the criteria of the World Health Organization 2010.

RESULTS

Of the 106 patients identified, 85 (80·2 per cent) were female, and the median age was 36 (range 10-65) years. Median tumour size was 4·5 (range 1·0-15·0) cm. Some 17 patients (16·0 per cent) were classified as having a high-grade malignant SPN. Tumour size of at least 5 cm was associated with high-grade malignant potential (P = 0·022). Although lymph nodes were removed from 40 patients (37·7 per cent), there were no nodal metastases. A total of five patients underwent en bloc resection of adjacent structures, including two with portal vein involvement. After a median follow-up of 56·9 months, two patients with high-grade malignant SPN had evidence of tumour recurrence in the lymph nodes and liver.

CONCLUSION

SPN with a diameter of 5 cm or more is associated with a high-grade malignant phenotype. Complete surgical removal is associated with low recurrence rates.

Surgical strategies for non-functioning pancreatic neuroendocrine tumours

BACKGROUND

The purpose of this study was to identify management strategies for non-functioning pancreatic neuroendocrine tumours (NF-PNETs) by analysis of surgical outcomes at a single institution.

METHODS

Archived records of patients with NF-PNETs who underwent surgery between 1994 and 2010 were reviewed.

RESULTS

Among 125 patients, the median tumour size was 2·5 (range 0·15-20·5) cm. Of the 51 NF-PNETs with a diameter of no more than 2 cm, 12 (24 per cent) were diagnosed as carcinoma. Overall 20 patients (16·0 per cent) had metastases to the lymph nodes. The minimum size of the tumour with lymph node metastasis was 1·2 cm. Having a NF-PNET of 2 cm or larger significantly increased the probability of a poorly differentiated carcinoma (P = 0·006), and having a NF-PNET of at least 2·5 cm significantly increased the probability of lymph node metastasis (P = 0·048). The 5-year cumulative survival rate after curative resection was 89·7 per cent. During a median follow-up of 31·5 months, there were 27 recurrences (23·1 per cent) and 13 disease-specific deaths (11·1 per cent) among the 117 patients who had an R0 resection. All patients who underwent repeat operations were alive without additional recurrence after a mean(s.d.) follow-up of 27·1(18·0) months.

CONCLUSION

Curative surgery should be performed for control of primary NF-PNETs. Lymph node dissection for NF-PNETs of 2·5 cm or larger and at least node sampling for tumours with a diameter of 1 cm or more are recommended. Debulking surgery should be considered for advanced tumours.

The outcomes after surgical resection in pancreatic endocrine tumors: an institutional experience

AIM

Sporadic pancreatic endocrine tumors (PET) can be managed surgically with excellent outcomes. The aim of this study was to analyze surgical outcomes and factors influencing survival.

METHODS

Between 1995 and 2007, 96 patients with sporadic PET who underwent surgery at our institution were retrospectively reviewed for clinicopathologic variables and outcomes according to the World Health Organization (WHO) classifications.

RESULTS

Thirty-nine patients had well-differentiated tumors (WDT) with benign behavior, 23 had uncertain behavior, 27 had low-grade carcinoma, and 7 were diagnosed with high-grade carcinoma. R0 resection was performed in 84 patients. No recurrence was observed in WDT regardless of its behavior or curability but 16 of 34 patients with carcinoma had recurrence. Five-year overall survival (OS) for R0-resected patients with carcinoma was 57%, and OS at 3 years for R1/R2-resected patients was 23% (P = 0.012). The WHO classification and R0 resection were independent prognostic factors in multivariate analysis.

CONCLUSIONS

This single institutional experience demonstrated that surgical resection is curative for WDT and recurrences are frequent in spite of curative resection for malignant PET. The WHO classification and R0 resection remained independent prognostic factor.

Construction and evaluation of cDNA libraries for large-scale expressed sequence tag sequencing in wheat (Triticum aestivum L.)

A total of 37 original cDNA libraries and 9 derivative libraries enriched for rare sequences were produced from Chinese Spring wheat (Triticum aestivum L.), five other hexaploid wheat genotypes (Cheyenne, Brevor, TAM W101, BH1146, Butte 86), tetraploid durum wheat (T. turgidum L.), diploid wheat (T. monococcum L.), and two other diploid members of the grass tribe Triticeae (Aegilops speltoides Tausch and Secale cereale L.). The emphasis in the choice of plant materials for library construction was reproductive development subjected to environmental factors that ultimately affect grain quality and yield, but roots and other tissues were also included. Partial cDNA expressed sequence tags (ESTs) were examined by various measures to assess the quality of these libraries. All ESTs were processed to remove cloning system sequences and contaminants and then assembled using CAP3. Following these processing steps, this assembly yielded 101,107 sequences derived from 89,043 clones, which defined 16,740 contigs and 33,213 singletons, a total of 49,953 "unigenes." Analysis of the distribution of these unigenes among the libraries led to the conclusion that the enrichment methods were effective in reducing the most abundant unigenes and to the observation that the most diverse libraries were from tissues exposed to environmental stresses including heat, drought, salinity, or low temperature.

A chromosome bin map of 2148 expressed sequence tag loci of wheat homoeologous group 7

The objectives of this study were to develop a high-density chromosome bin map of homoeologous group 7 in hexaploid wheat (Triticum aestivum L.), to identify gene distribution in these chromosomes, and to perform comparative studies of wheat with rice and barley. We mapped 2148 loci from 919 EST clones onto group 7 chromosomes of wheat. In the majority of cases the numbers of loci were significantly lower in the centromeric regions and tended to increase in the distal regions. The level of duplicated loci in this group was 24% with most of these loci being localized toward the distal regions. One hundred nineteen EST probes that hybridized to three fragments and mapped to the three group 7 chromosomes were designated landmark probes and were used to construct a consensus homoeologous group 7 map. An additional 49 probes that mapped to 7AS, 7DS, and the ancestral translocated segment involving 7BS also were designated landmarks. Landmark probe orders and comparative maps of wheat, rice, and barley were produced on the basis of corresponding rice BAC/PAC and genetic markers that mapped on chromosomes 6 and 8 of rice. Identification of landmark ESTs and development of consensus maps may provide a framework of conserved coding regions predating the evolution of wheat genomes.

A 2600-locus chromosome bin map of wheat homoeologous group 2 reveals interstitial gene-rich islands and colinearity with rice

The complex hexaploid wheat genome offers many challenges for genomics research. Expressed sequence tags facilitate the analysis of gene-coding regions and provide a rich source of molecular markers for mapping and comparison with model organisms. The objectives of this study were to construct a high-density EST chromosome bin map of wheat homoeologous group 2 chromosomes to determine the distribution of ESTs, construct a consensus map of group 2 ESTs, investigate synteny, examine patterns of duplication, and assess the colinearity with rice of ESTs assigned to the group 2 consensus bin map. A total of 2600 loci generated from 1110 ESTs were mapped to group 2 chromosomes by Southern hybridization onto wheat aneuploid chromosome and deletion stocks. A consensus map was constructed of 552 ESTs mapping to more than one group 2 chromosome. Regions of high gene density in distal bins and low gene density in proximal bins were found. Two interstitial gene-rich islands flanked by relatively gene-poor regions on both the short and long arms and having good synteny with rice were discovered. The map locations of two ESTs indicated the possible presence of a small pericentric inversion on chromosome 2B. Wheat chromosome group 2 was shown to share syntenous blocks with rice chromosomes 4 and 7.

Plant regeneration from hairy-root cultures transformed by infection with Agrobacterium rhizogenes in Catharanthus roseus

Hypocotyl explants of Catharanthus roseus produced hairy roots when cultured on Murashige and Skoog (MS) basal medium after infection by Agrobacterium rhizogenes. Explants gave rise to adventitious shoots at a frequency of up to 80% when cultured on MS medium supplemented with 31.1 microM 6-benzyladenine and 5.4 microM alpha-naphthaleneacetic acid. There was a significant difference in the frequency of adventitious shoot formation for each hairy-root line derived from a different cultivar. Plants derived from hairy roots exhibited prolific rooting and had shortened internodes. Approximately half of the plants had wrinkled leaves and an abundant root mass with extensive lateral branching, but otherwise appeared morphologically normal. Plants with hairy roots that were derived from the cultivar Cooler Apricot developed flowers with petals that were white in the proximal region, whereas the wild-type flower petals are red. PCR and Southern blot analyses revealed that plants derived from hairy roots retained the Ri TL-DNA.

Plant regeneration from hairy-root cultures transformed by infection with Agrobacterium rhizogenes in Catharanthus roseus

Hypocotyl explants of Catharanthus roseus produced hairy roots when cultured on Murashige and Skoog (MS) basal medium after infection by Agrobacterium rhizogenes. Explants gave rise to adventitious shoots at a frequency of up to 80% when cultured on MS medium supplemented with 31.1 microM 6-benzyladenine and 5.4 microM alpha-naphthaleneacetic acid. There was a significant difference in the frequency of adventitious shoot formation for each hairy-root line derived from a different cultivar. Plants derived from hairy roots exhibited prolific rooting and had shortened internodes. Approximately half of the plants had wrinkled leaves and an abundant root mass with extensive lateral branching, but otherwise appeared morphologically normal. Plants with hairy roots that were derived from the cultivar Cooler Apricot developed flowers with petals that were white in the proximal region, whereas the wild-type flower petals are red. PCR and Southern blot analyses revealed that plants derived from hairy roots retained the Ri TL-DNA.

Taxonomic discrimination of higher plants by pyrolysis mass spectrometry

Pyrolysis mass spectrometry (PyMS) is a rapid, simple, high-resolution analytical method based on thermal degradation of complex material in a vacuum and has been widely applied to the discrimination of closely related microbial strains. Leaf samples of six species and one variety of higher plants (Rosa multiflora, R. multiflora var. platyphylla, Sedum kamtschaticum, S. takesimense, S. sarmentosum, Hepatica insularis, and H. asiatica) were subjected to PyMS for spectral fingerprinting. Principal component analysis of PyMS data was not able to discriminate these plants in discrete clusters. However, canonical variate analysis of PyMS data separated these plants from one another. A hierarchical dendrogram based on canonical variate analysis was in agreement with the known taxonomy of the plants at the variety level. These results indicate that PyMS is able to discriminate higher plants based on taxonomic classification at the family, genus, species, and variety level.

Neocortical neurons cultured from mice with expanded CAG repeats in the huntingtin gene: unaltered vulnerability to excitotoxins and other insults

Glutamate-mediated excitotoxicity might contribute to the pathogenesis of Huntington's disease and other polyglutamine repeat disorders. We used murine neocortical cultures derived from transgenic and knock-in mice to test the effect of expression of expanded polyglutamine-containing huntingtin on neuronal vulnerability to excitotoxins or other insults. Neurons cultured from mice expressing either a normal length (Hdh(Q20)) or expanded (Hdh(Q111)) CAG repeat as a knock-in genetic alteration in exon one of the mouse Hdh gene [Hum Mol Genet 8 (1999) 115] had similar vulnerability to N-methyl-D-aspartate (NMDA) and kainate-mediated excitotoxicity. These neurons also exhibited similar vulnerability to oxidative stress (24 h exposure to 10-100 microM paraquat or 1-10 microM menadione), apoptosis (48 h exposure to 30-100 nM staurosporine or 1 microM dizocilpine maleate (MK-801) and proteasome inhibition (48 h exposure to 0.3-3 microM MG-132). Neocortical neurons cultured from mice transgenic for an expanded CAG repeat-containing exon 1 of the human HD gene (Mangiarini et al., 1996, R6/2 line) and non-transgenic littermate controls also had similar vulnerability to NMDA and kainate-mediated excitotoxicity. These observations suggest that expression of expanded polyglutamine-containing huntingtin does not acutely alter the vulnerability of cortical neurons to excitotoxic, oxidative or apoptotic insults.

Gas jets as ultrasonic waveguides

The study of the propagation of ultrasound within a gas jet is extended to obtain waveguide effects, where the jet collimates the ultrasonic beam from a transducer within the flow. Two methods have been investigated to achieve this--cooling the gas within the air jet, and using a different gas whose acoustic velocity is lower than air. Cooling an air jet to a temperature less than that of the surrounding air produced a noticeable waveguide effect. In addition, studies have been carried out using other selected gases, such as carbon dioxide (CO2) with a lower acoustic velocity than air, and helium (He) with a higher value. The former gas enhanced confinement of the ultrasonic beam, whereas the latter caused divergence. An ideal solution was found to be a CO2/air mixture, which produced a well-collimated sound field along the axis, while limiting the excess attenuation of pure CO2 gas jets. The effectiveness of the waveguide using mixed gas jets in producing images in air-coupled testing of solids is demonstrated.

Neurotrophin potentiation of iron-induced spinal cord injury

Previous studies have shown that pretreatment with neurotrophins can potentiate the vulnerability of cultured neurons to excitotoxic and free radical-induced necrosis, in contrast to their well known neuroprotective effects against apoptosis. Here we tested the hypothesis that this unexpected injury-potentiating effect of neurotrophins would also take place in the adult rat spinal cord. Fe(3+)-citrate was injected stereotaxically into spinal cord gray matter in adult rats in amounts sufficient to produce minimal tissue injury 24 h later. Twenty-four-hour pretreatment with brain-derived neurotrophic factor, neurotrophin-3, or neurotrophin-4/5, but not nerve growth factor, markedly enhanced tissue injury in the gray matter as evidenced by an increase in the damaged area, as well as the loss of neurons and oligodendrocytes. Consistent with maintained free radical mediation, the neurotrophin-potentiated iron-induced spinal cord damage was blocked by co-application of the antioxidant N-tert-butyl-(2-sulfophenyl)-nitrone. These data support the hypothesis that the overall neuroprotective properties of neurotrophins in models of acute injury to the spinal cord may be limited by an underlying potentiation of free radical-mediated necrosis.

Zinc translocation accelerates infarction after mild transient focal ischemia

Excess release of chelatable zinc (Zn(2+)) from central synaptic vesicles may contribute to the pathogenesis of selective neuronal cell death following transient forebrain ischemia, but a role in neurodegeneration after focal ischemia has not been defined. Adult male Long-Evans rats subjected to middle cerebral artery occlusion (MCAO) for 30 min followed by reperfusion developed delayed cerebral infarction reaching completion 3 days after the insult. One day after the insult, many degenerating cerebral neurons exhibited increased intracellular Zn(2+), and some labeled with the antibody against activated caspase-3. I.c.v. administration of the Zn(2+) chelator, EDTA saturated with equimolar Ca(2+) (CaEDTA), 15 min prior to ischemia attenuated subsequent Zn(2+) translocation into cortical neurons, and reduced infarct volume measured 3 days after ischemia. Although the protective effect of CaEDTA at this endpoint was substantial (about 70% infarct reduction), it was lost when insult severity was increased (from 30 to 60 min MCAO), or when infarct volume was measured at a much later time point (14 days instead of 3 days after ischemia). These data suggest that toxic Zn(2+) translocation, from presynaptic terminals to post-synaptic cell bodies, may accelerate the development of cerebral infarction following mild transient focal ischemia.

Preconditioned resistance to oxygen-glucose deprivation-induced cortical neuronal death: alterations in vesicular GABA and glutamate release

Central neurons exposed to several types of sublethal stress, including ischemia, acquire resistance to injury induced by subsequent ischemic insults, a phenomenon called ischemic preconditioning. We modeled this phenomenon in vitro, utilizing exposure to 45 mM KCl to reduce the vulnerability of cultured murine cortical neurons to subsequent oxygen-glucose deprivation. Twenty-four hours after preconditioning, cultures exhibited enhanced depolarization-induced, tetanus toxin-sensitive GABA release and a modest decrease in glutamate release. Total cellular GABA levels were unaltered. Inhibition of GABA degradation with the GABA transaminase inhibitor (+/-)-gamma-vinyl GABA, or addition of low levels of GABA, muscimol, or chlormethiazole to the bathing medium, mimicked the neuroprotective effect of preconditioning against oxygen-glucose deprivation-induced death. However, neuronal death was enhanced by higher levels of these manipulations, as well as by prior selective destruction of GABAergic neurons by kainate. Finally, selective blockade of GABA(A) receptors during oxygen-glucose deprivation or removal of GABAergic neurons eliminated the neuroprotective effects of prior preconditioning. Taken together, these data predict that presynaptic alterations, specifically enhanced GABA release together with reduced glutamate release, may be important mediators of ischemic preconditioning, but suggest caution in regard to interventions aimed at increasing GABA(A) receptor activation.

7-Chlorokynurenate Blocks NMDA Receptor-Mediated Neurotoxicity in Murine Cortical Culture

We examined the neuroprotective actions of the glycine site N-methyl-D-aspartate (NMDA) antagonist, 7-chlorokynurenate, in murine neocortical cell cultures. Cultures exposed for 5 min to 100 - 500 microM NMDA in the absence of added glycine developed substantial neuronal degeneration over the next 24 h. The addition of 10 microM glycine did not increase submaximal NMDA-induced neuronal injury, suggesting that endogenous glycine levels were sufficient to saturate its receptor sites on NMDA receptor complexes. Addition of 3 - 300 microM 7-chlorokynurenate produced concentration-dependent reduction in this neuronal damage with an IC50 of approximately 30 microM. Some injury reduction was seen even if the drug was added after completion of the NMDA exposure. The protective effect of 100 microM 7-chlorokynurenate could be overcome by adding 10 - 1000 microM glycine (glycine median effective concentration (EC50) approximately 100 microM) or 1 mM D-serine. As predicted by its ability to block NMDA receptor-mediated injury, 10 - 300 microM 7-chlorokynurenate also produced concentration-dependent reduction in the neuronal loss induced by 50 - 60 min exposure to combined glucose and oxygen deprivation. These data support the suggestion that pharmacologic interference with the binding of glycine to the NMDA receptor complex represents a potentially effective approach to blocking NMDA receptor-induced neurotoxicity in ischemia.

Gas jet as a waveguide for air-coupled ultrasound

The directional characteristics of an ultrasonic signal have been studied during propagation within an axial gas jet. The effects of nozzle shape, nozzle diameter, and variations in jet velocity, temperature and gas composition have been investigated. At high flow velocities of an air jet, divergence of the ultrasonic beam was observed. This was attributed to the effects of refraction, caused by increased acoustic velocities in the direction of the flow. An effective waveguide was also demonstrated by cooling the air jet to below ambient temperatures, so that the acoustic velocity in the air jet was lower than that in the surrounding atmosphere. This could also be achieved by using carbon dioxide mixed with air, whereas the use of helium led to increased divergence. The result is likely to be of use in air-coupled ultrasonic materials inspection.

Sarcoma and Sarcomatous Metaplastic Carcinoma of the Breast

PURPOSE

Primary sarcoma and SMC (sarcomatous metaplastic carcinoma) of the breast are very rare tumors, accounting for less than 1% of all breast malignancies. There are many controversies concerning the biological characteristics, prognosis and optimal treatment of these tumors owing to the rarity of incidence. The aims of this study were to elucidate the clinicopathologic characteristics of these tumors and to assist in elucidating the optimal treatment plan for the disease.

MATERIALS AND METHODS

13 cases of primary sarcoma and 10 cases of SMC that had been treated at KCCH between 1984 and 2001 were retrospectively reviewed. Phyllodes tumors were excluded from our study.

RESULTS

Among the 13 cases of primary sarcoma included, stromal sarcoma occurred in 5 cases, osteosarcoma in 3 cases, angiosarcoma in 3 cases and spindle cell sarcoma in 2 cases. The mean age of the patients with primary sarcoma and SMC was 39.7 years and 55.1 years respectively (p=0.002). When survival rates were compared according to histologic types, size of tumor, histologic grade, type of surgery and use of adjuvant therapy, both size of tumor (p=0.0256) and histologic grade (p=0.0197) were shown to be prognostic factors.

CONCLUSION

There were no significantly different features between primary sarcoma and SMC in terms of biologic characteristics or survival rates, with the exception that patients with SMC were older than those with primary sarcoma. Histologic grade and size of tumor were significant prognostic factors of these tumors.

Cycloheximide reduces infarct volume when administered up to 6 h after mild focal ischemia in rats

We have previously described a rodent model of brief (30 min) middle cerebral artery occlusion followed by reperfusion, in which infarction develops gradually, reaching completion more than 3 days after ischemia, accompanied by morphological, biochemical, and pharmacological evidence of apoptosis. In the present study, we tested the hypotheses that delayed administration of a protein synthesis inhibitor would be effective in reducing tissue injury in this slowly evolving ischemic infarction, and that efficacy of this treatment would wane with more prolonged ischemia. Focal cerebral ischemia was induced in Long-Evans rats by occlusion of the right middle cerebral artery. Infarction volume was analyzed using triphenyl tetrazolium chloride staining, and morphology was studied using hematoxylin and eosin stained sections. Following 30 min middle cerebral artery occlusion and reperfusion, the core ischemic region exhibited vacuolization in the neuropil by 36 h after ischemia, and infarction reached full size by 7 days after ischemia. Cycloheximide reduced infarct volume when given up to 6 h after ischemia. If the duration of ischemic insult was increased to 90 min, the therapeutic window for delayed cycloheximide was only 30 min. In permanent middle cerebral artery occlusion, cycloheximide was ineffective even when given prior to ischemia onset. After mild, but not severe, ischemic insults, cerebral infarction develops slowly and may be treatable with protein synthesis inhibitors, even when treatment is delayed for up to 6 h after the onset of ischemia.

Zinc induces a Src family kinase-mediated up-regulation of NMDA receptor activity and excitotoxicity

Zinc is coreleased with glutamate from excitatory nerve terminals throughout the central nervous system and acutely inhibits N-methyl-d-aspartate (NMDA) receptor activation. Here we report that cultured murine cortical neurons briefly exposed to sublethal concentrations of zinc developed increased intracellular free Na(+), phosphorylation of Src kinase at tyrosine 220, and tyrosine phosphorylation of NMDA receptor 2A/2B subunits, in a fashion sensitive to the Src family kinase inhibitor 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine, PP2. Functionally, this zinc exposure produced a delayed increase in NMDA receptor current in perforated patch but not conventional whole-cell recordings, as well as an increase in NMDA receptor-mediated cell death. These observations suggest that the effect of synaptically released zinc on neuronal NMDA receptors may be biphasic: acute block, followed by Src family kinase-mediated up-regulation of NMDA receptor activity and cytotoxicity.

Ion homeostasis and apoptosis

Alterations in the transmembrane gradients of several physiological ions may influence programmed cell death. In particular, recent data suggest that increases in intracellular calcium may either promote or inhibit apoptosis, depending on the level, timing and location, whereas loss of intracellular potassium promotes apoptosis.

Reciprocal expressions of cyclin E and cyclin D1 in hepatocellular carcinoma

Deregulation of the cell cycle by overexpression of G1 cyclins, cyclin E and cyclin D1 genes, has been demonstrated to be a prerequisite for the development of human cancer. Recently, cyclin E is proposed to be sufficient for the progression of the G1 cell cycle without cyclin D1. Here we show that the proposed model system was specifically present in human hepatocellular carcinoma (HCC) unlike other human cancers. Of 31 HCC tissues analyzed, 21 (67.7%) exhibited an overexpression of cyclin E protein. In contrast to cyclin E gene expression, cyclin D1 expression was strongly downregulated in 19 (61.2%) HCCs. Interestingly, 65% of HCC tissues with overexpression of the cyclin E gene exhibited downregulation of cyclin D1, suggesting reciprocal deregulation of these cyclins in the G1 progression of the cell cycle. Southern blot analysis proved the amplification of cyclin E gene in HCC with a high level of overexpression. The present findings suggest that the reciprocal deregulation of cyclin E lacking cyclin D1 expression might play a role in G1 progression and the development of HCC.

Nitric oxide reduces Ca(2+) and Zn(2+) influx through voltage-gated Ca(2+) channels and reduces Zn(2+) neurotoxicity

The translocation of synaptic Zn(2+) from nerve terminals into selectively vulnerable neurons may contribute to the death of these neurons after global ischemia. We hypothesized that cellular Zn(2+) overload might be lethal for reasons similar to cellular Ca(2+) overload and tested the hypothesis that Zn(2+) neurotoxicity might be mediated by the activation of nitric oxide synthase. Although Zn(2+) (30-300microM) altered nitric oxide synthase activity in cerebellar extracts in solution, it did not affect nitric oxide synthase activity in cultured murine neocortical neurons. Cultured neurons exposed to 300-500microM Zn(2+) for 5min under depolarizing conditions developed widespread degeneration over the next 24h that was unaffected by the concurrent addition of the nitric oxide synthase inhibitor N(G)-nitro-L-arginine. Furthermore, Zn(2+) neurotoxicity was attenuated when nitric oxide synthase activity in the cultures was induced by exposure to cytokines, exogenous nitric oxide was added or nitric oxide production was pharmacologically enhanced. The unexpected protective effect of nitric oxide against Zn(2+) toxicity may be explained, at least in part, by reduction of toxic Zn(2+) entry. Exposure to nitric oxide donors reduced Ba(2+) current through high-voltage activated calcium channels, as well as K(+)-stimulated neuronal uptake of 45Ca(2+) or 65Zn(2+). The oxidizing agents thimerosal and 2,2'-dithiodipyridine also reduced K(+)-stimulated cellular 45Ca(2+) uptake, while akylation of thiols by pretreatment with N-ethylmaleimide blocked the reduction of 45Ca(2+) uptake by a nitric oxide donor.The results suggest that Zn(2+)-induced neuronal death is not mediated by the activation of nitric oxide synthase; rather, available nitric oxide may attenuate Zn(2+) neurotoxicity by reducing Zn(2+) entry through voltage-gated Ca(2+) channels, perhaps by oxidizing key thiol groups.

L-type Ca(2+) channel-mediated Zn(2+) toxicity and modulation by ZnT-1 in PC12 cells

In view of evidence that Zn(2+) neurotoxicity contributes to some forms of pathological neuronal death, we developed a model of Zn(2+) neurotoxicity in a cell line amenable to genetic manipulations. Exposure to 500 microM ZnCl(2) for 15 min under depolarizing conditions resulted in modest levels of PC12 cell death, that was reduced by the L-type Ca(2+) channel antagonist, nimodipine, and increased by the L-type Ca(2+) channel opener, S(-)-Bay K 8644. At lower insult levels (200 micrometer Zn(2+)+Bay K 8644), Zn(2+)-induced death appeared apoptotic under electron microscopy and was sensitive to the caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-CH(2)F (Z-VAD); at higher insult levels (1000 microM+Bay K 8644), cells underwent necrosis insensitive to Z-VAD. To test the hypothesis that the plasma membrane transporter, ZnT-1, modulates Zn(2+) neurotoxicity, we generated stable PC12 cell lines overexpressing wild type or dominant negative forms of rat ZnT-1 (rZnT-1). Clones T9 and T23 overexpressing wild type rZnT-1 exhibited enhanced Zn(2+) efflux and reduced vulnerability to Zn(2+)-induced death compared to the parental line, whereas clones D5 and D16 expressing dominant negative rZnT-1 exhibited the opposite characteristics.

Differences in vulnerability to permanent focal cerebral ischemia among 3 common mouse strains

BACKGROUND AND PURPOSE

Genetically engineered mice are used to study the role of single genes in cerebral ischemia, but inherent, strain-dependent differences in neuronal vulnerability may affect experimental end points. To examine this possibility, tissue injury resulting from focal ischemia and its relationship to cerebral hemodynamics were determined in 3 common mutant mouse strains.

METHODS

Permanent middle cerebral artery ligation was performed in male C57BL/6J, Balb/C, and 129X1/SvJ mice. Mean arterial blood pressure, blood gases, basal and postischemic cortical blood flow ([(14)C]iodoantipyrine autoradiography and laser-Doppler flowmetry), posterior communicating artery patency, and infarct size were determined.

RESULTS

Basal cortical blood flow did not differ among strains. Ten minutes after middle cerebral artery ligation, relative red cell flow in the ischemic cortex was 6% to 7% of preischemic flow in every strain. Despite similar hemodynamics, cortical infarcts in Balb/C mice were 3-fold larger than those in 129X1/SvJ and C57BL/6J mice; infarct size in the latter 2 strains was not significantly different. The posterior communicating artery was either poorly developed or absent in >90% of the Balb/C and C57BL/6J but in <50% of the 129X1/SvJ mice.

CONCLUSIONS

The extent of ischemic injury differed markedly between the 3 strains. The presence and patency of posterior communicating arteries, although variable among strains, did not affect preischemic or postischemic cortical blood flow or bear any relationship to ischemic injury. Therefore, intrinsic factors, other than hemodynamic variability, may contribute to the differences in ischemic vulnerability among strains. These findings underscore the importance of selecting genetically matched wild-type controls.

Neuronal apoptosis after CNS injury: the roles of glutamate and calcium

While a role has been well established for excitotoxic necrosis in the pathogenesis of traumatic or ischemic damage to the CNS, accumulating evidence now suggests that apoptosis may also be a prominent contributor. In this review we focus on the role of glutamate and attendant intracellular calcium influx in triggering or modifying excitotoxic necrosis and apoptosis, raising the possibility that calcium influx may affect these two death pathways in opposite directions. Incorporating consideration of both pathways will probably be needed to develop the most effective neuroprotective treatments for CNS injury.

Neurobiology of disease

Advances in technology and basic sciences this past decade have transformed neurobiological research. Practitioners looking prospectively in 1990 could hardly have hoped for the diagnostics and rational therapeutics that have become part of regular practice today. Here, we discuss three areas that have had great impact: genetics, cell death, and stem cell/gene therapy research.

Zn2+ current is mediated by voltage-gated Ca2+ channels and enhanced by extracellular acidity in mouse cortical neurones

1. Mammalian neuronal voltage-gated Ca2+ channels have been implicated as potential mediators of membrane permeability to Zn2+. We tested directly whether voltage-gated Ca2+ channels can flux Zn2+ in whole-cell voltage-clamp recordings from cultured murine cortical neurones. 2. In the presence of extracellular Zn2+ and no Na+, K+, or other divalent cations, a small, non-inactivating, voltage-gated inward current was observed exhibiting a current-voltage relationship characteristic of high-voltage activated (HVA) Ca2+ channels. Inward current was detectable at Zn2+ levels as low as 50 microM, and both the amplitude and voltage sensitivity of the current depended upon Zn2+ concentration. This Zn2+ current was sensitive to blockade by Gd3+ and nimodipine and, to a lesser extent, by omega-conotoxin GVIA. 3. Zn2+ could permeate Ca2+ channels in the presence of Ca2+ and other physiological cations. Inward currents recorded with 2 mM Ca2+ were attenuated by Zn2+ (IC50 = 210 microM), and currents recorded with Zn2+ were unaffected by up to equimolar Ca2+ concentrations. Furthermore, the Zn2+-selective fluorescent dye Newport Green revealed a depolarisation-activated, nimodipine-sensitive Zn2+ influx into cortical neurones that were bathed in a physiological extracellular solution plus 300 microM ZnCl2. 4. Surprisingly, while lowering extracellular pH suppressed HVA Ca2+ currents, Zn2+ current amplitude was affected oppositely, varying inversely with pH with an apparent pK of 7.4. The acidity-induced enhancement of Zn2+ current was associated with a positive shift in reversal potential but no change in the kinetics or voltage sensitivity of channel activation. 5. These results provide evidence that L- and N-type voltage-gated Ca2+ channels can mediate Zn2+ entry into cortical neurones and that this entry may be enhanced by extracellular acidity.

Expression of the barley dehydrin multigene family and the development of freezing tolerance

Dehydrins (DHNs; LEA D11) are one of the typical families of plant proteins that accumulate in response to dehydration, low temperature, osmotic stress or treatment with abscisic acid (ABA), or during seed maturation. We previously found that three genes encoding low-molecular-weight DHNs (Dhn1, Dhn2 and Dhn9) map within a 15-cM region of barley chromosome 5H that overlaps a QTL for winterhardiness, while other Dhn genes encoding low- and high-molecular-weight DHNs are located on chromosomes 3H, 4H and 6H. Here we examine the expression of specific Dhn genes under conditions associated with expression of the winterhardiness phenotype. Plants grown at 4 degrees C or in the field in Riverside, California developed similar, modest levels of freezing tolerance, coinciding with little low-MW Dhn gene activity. Dicktoo (the more tolerant cultivar) and Morex (the less tolerant) grown in Saskatoon, Canada expressed higher levels of expression of genes for low-MW DHNs than did the same cultivars in Riverside, with expression being higher in Dicktoo than Morex. Dehydration or freeze-thaw also evoked expression of genes for low MW DHNs, suggesting that the dehydration component of freeze-thaw in the field induces low expression of genes encoding low-MW DHNs. These observations are consistent with the hypothesis that the major chilling-induced DHNs help to prime plant cells for acclimation to more intense cold, which then involves adaptation to dehydration during freeze-thaw cycling. A role for chromosome 5H-encoded DHNs in acclimation to more intense cold seems possible, even though it is not the basis of the major heritable variation in winterhardiness within the Dicktoo x Morex population.

Factors involved in hepatic glutathione depletion induced by acute ethanol administration

Factors implicated in changes of the hepatic glutathione concentration following acute ethanol administration were examined in rats. Adult female rats were treated with either ethanol (4 g/kg, p.o.) or an isocaloric glucose solution. The hepatic reduced glutathione (GSH) concentration decreased rapidly after ethanol intake with a maximum diminution, approximately 50% of the control value, being observed at t = 6 h. The hepatic GSH concentration gradually increased, and finally rebounded at 24 h after ethanol ingestion. The dose of ethanol induced a transient increase in the oxidized glutathione (GSSG)/GSH ratio, which was associated with a significant reduction in GSH rather than elevation in GSSG [corrected]. The activity of gamma-glutamylcysteine synthetase (GCS), the rate-limiting enzyme for glutathione synthesis, and the cysteine concentration in liver were also measured. The GCS activity was depressed to approximately 80% of the control value at t = 2.5 h followed by rapid recovery, but no difference in the hepatic cysteine concentration between control and ethanol treated rats was observed for 24 h, suggesting that the reduction in glutathione synthesis may not play a major role in the significant depletion of this tripeptide in liver. The total glutathione concentration was measured both in prehepatic and posthepatic inferior vena cava blood. The glutathione concentration in posthepatic blood was approximately twice as high as that of prehepatic blood in control rats. Acute ethanol administration doubled the elevation of glutathione in posthepatic blood measured at t = 2.5 h. The sinusoidal efflux of glutathione estimated from the increase in blood glutathione concentration was greater than the total amount of its depletion in the liver of rats treated with ethanol. The results suggest that in the liver of rats treated acutely with ethanol, glutathione efflux plays the most important role in the reduction of this tripeptide, which would be aggravated by a transient decrease in glutathione synthesis and by increased consumption in association with its metabolism.

Identification and characterization of nitric oxide synthase in Salmonella typhimurium

The presence of the nitric oxide synthase (NOS) enzyme from Salmonella typhimurium (S. typhimurium) was identified by measuring radiolabeled L-[3H]citrulline and NO, and Western blot analysis. NOS was partially purified by both Mono Q ion exchange and Superose 12HR size exclusion column chromatography, sequentially. The molecular weight of NOS was estimated to be 93.3 kDa by Western blot analysis. The enzyme showed a significant dependency on the typical NOS cofactors; an apparent Km for L-arginine of 34.7 mM and maximum activity between 37 degrees C and 43 degrees C. The activity was inhibited by NOS inhibitors such as aminoguanidine and N(G),N(G)-dimethyl-L-arginine. Taken together, partially purified NOS in S. typhimurium is assumed to be a different isoform of mammalian NOSs.

Zinc-induced neuronal death in cortical neurons

Although Zn2+ is normally stored and released in the brain, excessive exposure to extracellular Zn2+ can be neurotoxic. The purpose of the present study was to determine the type of neuronal cell death, necrosis versus apoptosis, induced by Zn2+ exposure. Addition of 10-50 microM ZnCl2 to the bathing medium of murine neuronal and glial cell cultures induced, over the next 24 hrs., Zn2+-concentration-dependent neuronal death; some glial death also occurred with Zn2+ concentrations above 30 microM. The neuronal death induced by 20 microM Zn2+ was characterized by coarse chromatin condensation, the formation of apoptotic bodies, and internucleosomal DNA fragmentation. It was attenuated in cortical cell cultures prepared from mice null for the bax gene, and by the caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp-CH2F (ZVAD, 100 microM), but not by the NMDA receptor antagonist, D-2-amino-5-phosphonovalerate (D-APV, 200 microM ). In contrast, the neuronal death induced by 50 microM Zn2+ was characterized by plasma membrane disruption and random DNA fragmentation; this death was attenuated by D-APV, but exhibited little sensitivity to ZVAD or deletion of bax. These results suggest that Zn2+ can induce cell death with characteristics of either apoptosis or necrosis, depending on the intensity of the Zn2+ exposure.

Zinc-induced cortical neuronal death: contribution of energy failure attributable to loss of NAD(+) and inhibition of glycolysis

Excessive zinc influx may contribute to neuronal death after certain insults, including transient global ischemia. In light of evidence that levels of intracellular free Zn(2+) associated with neurotoxicity may be sufficient to inhibit glyceraldehyde-3-phosphate dehydrogenase (GAPDH), experiments were performed looking for reduced glycolysis and energy failure in cultured mouse cortical neurons subjected to lethal Zn(2+) exposure. As predicted, cultures exposed for 3-22 hr to 40 mixroM Zn(2+) developed an early increase in levels of dihydroxy-acetone phosphate (DHAP) and fructose 1,6-bisphosphate (FBP) and a progressive loss of ATP levels, followed by neuronal cell death; furthermore, addition of the downstream glycolytic substrate pyruvate to the bathing medium attenuated the fall in ATP and neuronal death. However, an alternative to direct Zn(2+) inhibition of GAPDH was raised by the observation that Zn(2+) exposure also induced an early decrease in nicotinamide-adenine dinucleotide (NAD(+)) levels, an event itself capable of inhibiting GAPDH. Favoring this indirect mechanism of GAPDH inhibition, the neuroprotective effects of pyruvate addition were associated with normalization of cellular levels of NAD(+), DHAP, and FBP. Zn(2+)-induced neuronal death was also attenuated by addition of the energy substrate oxaloacetate, the activator of pyruvate dehydrogenase, dichloroacetate, or the inhibitors of NAD(+) catabolism, niacinamide or benzamide. Acetyl carnitine, alpha-keto butyrate, lactate, and beta-hydroxy-butyrate did not attenuate Zn(2+)-induced neurotoxicity, perhaps because they could not regenerate NAD(+) or be used for energy production in the presence of glucose.

Apoptosis and necrosis in cerebrovascular disease

Neuronal death following ischemic insults has been thought to reflect necrosis. However, recent evidence from several labs suggests that programmed cell death, leading to apoptosis, might additionally contribute to this death. We have used both in vitro and in vivo models to study the role of apoptosis in ischemic cell death. Some features of apoptosis (TUNEL staining, internucleosomal DNA fragmentation, sensitivity to cycloheximide) were observed following transient focal ischemia in rats. Brief transient focal ischemia was followed by delayed infarction more than 3 days later; this delayed infarction was sensitive to cycloheximide. A cycloheximide-sensitive component of neuronal cell death was also observed in cultured murine neocortical neurons deprived of oxygen-glucose in the presence of glutamate receptor antagonists. This presumed ischemic apoptosis was attenuated by caspase inhibitors, or by homozygous deletion of the bax gene. Neurons may undergo both apoptosis and necrosis after ischemic insults, and thus it may be therapeutically desirable to block both processes.

General pharmacology studies on beta-domain deleted recombinant factor VIII

beta-Domain deleted recombinant factor VIII (GC-rAHF), newly developed by Korea Green Cross Co., is a novel therapeutic for hemophiliacs and is currently under clinical evaluation. The general pharmacological properties of this drug were evaluated using mice, rats, guinea pigs and rabbits. Intravenous doses of 5 to 500 IU/kg were assayed in several tests to analyze their effects in vivo on various systems. The effect of the substance under study was also tested in vitro on isolated guinea pig ileum preparations at final concentrations of 5 to 50 IU/kg. The result of this study showed that GC-rAHF did not affect general behavior in the Irwin test. Similarly the drug was not found to affect neither normal body temperature nor the spontaneous activity in mice. In addition, it was not found to induce pharmacologically significant alterations of the cardiovascular and respiratory parameters in rats. No effects were observed either in the pentobarbital sodium-induced sleep-induction time and duration, in writhing test or in the test of pentetrazole-induced convulsion. Finally, the tested drug did not modify the gastrointestinal motility, acetylcholine or histamine-induced contraction of the isolated guinea pig ileum, nor gastric secretion. The results demonstrated that GC-rAHF has no effects on the central nervous, cardiovascular, respiratory and digestive systems in the doses of 5, 50 and 500 IU/kg in vivo and 5, 10, 50 and 100 IU/kg in vitro.

Transplanted embryonic stem cells survive, differentiate and promote recovery in injured rat spinal cord

Transplantation approaches using cellular bridges, fetal central nervous system cells, fibroblasts expressing neurotrophin-3 (ref. 6), hybridoma cells expressing inhibitory protein-blocking antibodies, or olfactory nerves ensheathing glial cells transplanted into the acutely injured spinal cord have produced axonal regrowth or functional benefits. Transplants of rat or cat fetal spinal cord tissue into the chronically injured cord survive and integrate with the host cord, and may be associated with some functional improvements. In addition, rats transplanted with fetal spinal cord cells have shown improvements in some gait parameters, and the delayed transplantation of fetal raphe cells can enhance reflexes. We transplanted neural differentiated mouse embryonic stem cells into a rat spinal cord 9 days after traumatic injury. Histological analysis 2-5 weeks later showed that transplant-derived cells survived and differentiated into astrocytes, oligodendrocytes and neurons, and migrated as far as 8 mm away from the lesion edge. Furthermore, gait analysis demonstrated that transplanted rats showed hindlimb weight support and partial hindlimb coordination not found in 'sham-operated' controls or control rats transplanted with adult mouse neocortical cells.

Prevention of neuronal apoptosis by phorbol ester-induced activation of protein kinase C: blockade of p38 mitogen-activated protein kinase

Consistent with previous studies on cell lines and non-neuronal cells, specific inhibitors of protein kinase C induced mouse primary cultured neocortical neurons to undergo apoptosis. To examine the complementary hypothesis that activating protein kinase C would attenuate neuronal apoptosis, the cultures were exposed for 1 h to phorbol-12-myristate-13-acetate, which activated protein kinase C as evidenced by downstream enhancement of the mitogen-activated protein kinase pathway. Exposure to phorbol-12-myristate-13-acetate, or another active phorbol ester, phorbol-12,13-didecanoate, but not to the inactive ester, 4alpha-phorbol-12,13-didecanoate, markedly attenuated neuronal apoptosis induced by serum deprivation. Phorbol-12-myristate-13-acetate also attenuated neuronal apoptosis induced by exposure to beta-amyloid peptide 1-42, or oxygen-glucose deprivation in the presence of glutamate receptor antagonists. The neuroprotective effects of phorbol-12-myristate-13-acetate were blocked by brief (non-toxic) concurrent exposure to the specific protein kinase C inhibitors, but not by a specific mitogen-activated protein kinase 1 inhibitor. Phorbol-12-myristate-13-acetate blocked the induction of p38 mitogen-activated protein kinase activity and specific inhibition of this kinase by SB 203580 attenuated serum deprivation-induced apoptosis. c-Jun N-terminal kinase 1 activity was high at rest and not modified by phorbol-12-myristate-13-acetate treatment. These data strengthen the idea that protein kinase C is a key modulator of several forms of central neuronal apoptosis, in part acting through inhibition of p38 mitogen-activated protein kinase regulated pathways.

Selective activation of group II mGluRs with LY354740 does not prevent neuronal excitotoxicity

Recent reports have suggested a role for group II metabotropic glutamate receptors (mGluRs) in the attenuation of excitotoxicity. Here we examined the effects of the recently available group II agonist (+)-2-Aminobicyclo[3.1.0]hexane-2-6-dicarboxylic acid (LY354740) on N-methyl-D-aspartate (NMDA)-induced excitotoxic neuronal death, as well as on hypoxic-ischemic neuronal death both in vitro and in vivo. At concentrations shown to be selective for group II mGluRs expressed in cell lines (0.1-100 nM), LY354740 did not attenuate NMDA-mediated neuronal death in vitro or in vivo. Furthermore, LY354740 did not attenuate oxygen-glucose deprivation-induced neuronal death in vitro or ischemic infarction after transient middle cerebral artery occlusion in rats. In addition, the neuroprotective effect of another group II agonist, (S)-4-carboxy-3-phenylglycine (4C3HPG), which has shown injury attenuating effects both in vitro and in vivo, was not blocked by the group II antagonists (2 S)-alpha-ethylglutamic acid (EGLU), (RS)-alpha-methyl-4-sulphonophenylglycine (MSPG), or the group III antagonist (S)-alpha-methyl-3-carboxyphenylalanine (MCPA), suggesting that this neuroprotection may be mediated by other effects such as upon group I mGluRs.

Measurement of intracellular free zinc concentrations accompanying zinc-induced neuronal death

Toxic zinc influx may contribute to selective neuronal death after transient global ischemia. We previously used the high-affinity (K(D) = 27 nm) fluorescent dye mag-fura-5 to detect initial increases in neuronal intracellular free Zn(2+) ([Zn(2+)](i)) associated with brief Zn(2+) exposure. Here we used the specific low-affinity Zn(2+) indicator Newport Green (K(D) = 1 microm) to measure the peak levels of [Zn(2+)](i) attained during prolonged, toxic exposures to extracellular Zn(2+). Murine cortical cell cultures exposed for 5-10 min to 300 microm Zn(2+) in the presence of kainate or elevated extracellular K(+) developed widespread neuronal death over the next 24 hr. Such Zn(2+) exposure under depolarizing conditions was accompanied by a large increase in [Zn(2+)](i) reaching several hundred nanomolar, which gradually recovered over the next 20-40 min after termination of Zn(2+) exposure. Both the level of [Zn(2+)](i) elevation and the extent of subsequent neuronal death depended on the concentration of extracellular Zn(2+) between 30 microm and 1 mm. In contrast, exposure to 300 microm Zn(2+) in the presence of 300 microm NMDA resulted in little increase in [Zn(2+)](i) and little neuronal death, suggesting that NMDA receptor-gated channels are less important as a route of toxic Zn(2+) entry than voltage-gated calcium channels.

Role of the outward delayed rectifier K+ current in ceramide-induced caspase activation and apoptosis in cultured cortical neurons

We studied the novel hypothesis that an up-modulation of channels for outward delayed rectifier K+ current (I(K)) plays a key role in ceramide-induced neuronal apoptosis. Exposure for 6-10 h to the membrane-permeable C2-ceramide (25 microM) or to sphingomyelinase (0.2 unit/ml), but not to the inactive ceramide analogue C2-dihydroceramide (25 microM), enhanced the whole-cell I(K) current without affecting the transient A-type K+ current and increased caspase activity, followed by neuronal apoptosis 24 h after exposure onset. Tetraethylammonium (TEA) or 4-chloro-N,N-diethyl-N-heptylbenzenebutanaminium tosylate (clofilium), at concentrations inhibiting I(K), attenuated the C2-ceramide-induced caspase-3-like activation as well as neuronal apoptosis. Raising extracellular K+ to 25 mM similarly blocked the C2-ceramide-induced cell death; the neuroprotection by 25 mM K+ or TEA was not eliminated by blocking voltage-gated Ca2+ channels. An inhibitor of tyrosine kinases, herbimycin A (10 nM) or lavendustin A (0.1-1 microM), suppressed I(K) enhancement and/or apoptosis induced by C2-ceramide. It is suggested that ceramide-induced I(K) current enhancement is mediated by tyrosine phosphorylation and plays a critical role in neuronal apoptosis.

Attenuation of cortical neuronal apoptosis by gangliosides

Addition of the natural gangliosides monosialoganglioside (GM1), disialoganglioside, trisialoganglioside, or tetrasialoganglioside in the range of 10 to 100 microM, but not asialoganglioside lacking the sialic acid moiety, attenuated cortical neuronal apoptosis induced by serum deprivation, ionomycin, or cyclosporin A but not by protein kinase inhibitors (staurosporine, genistein, lavendustin A, or herbimycin A). Coaddition of 100 nM wortmannin, a selective inhibitor of phosphatidylinositol 3-kinase, but not 1 microM Go6976, a selective protein kinase C inhibitor, blocked the neuroprotective effect of GM1. In contrast to its antiapoptotic effect, GM1 at up to 200 microM did not attenuate cortical neuronal necrosis induced by exposure to the excitotoxins N-methyl-D-aspartate or kainate. Furthermore, GM1 increased the necrosis induced by oxidative stress (addition of Fe(2+) or buthionine sulfoximine). These data suggest that neuroprotective effects of natural gangliosides may preferentially reflect reduction of neuronal apoptosis rather than necrosis, and be mediated through mechanisms involving activation of phosphatidylinositol 3-kinase.

The changing landscape of ischaemic brain injury mechanisms

Thrombolysis has become established as an acute treatment for human stroke. But despite multiple clinical trials, neuroprotective strategies have yet to be proved effective in humans. Here we discuss intrinsic tissue mechanisms of ischaemic brain injury, and present a perspective that broadening of therapeutic targeting beyond excitotoxicity and neuronal calcium overload will be desirable for developing the most effective neuroprotective therapies.

The application of ion chromatographic method for bioavailability and stability test of iron preparations

Postabsorptive serum iron level was determined after oral administration of the compounds to human. In serum and whole blood, Fe3+ was measured by ion chromatography (IC) using a pyridine-2,6-dicarboxylic acid (PDCA) as an eluent. The serum sample solutions were pretreated with I N HCI and 50% TCA. The whole blood sample solutions were treated with 3 N HCI for 30 min at 125 degrees C. The limit of detection (LOD) of the IC technique is 0.2 microM for Fe2- and 0.1 microM for Fe3+. The area under concentration (AUC) can be obtained by the above analytical condition. In addition, to compare the stability of Fe2+ to that of Fe3+ in pharmaceutical preparations, accelerated stability test was carried out. After storing the samples under 40 degrees C, 75%RH in light-resistant container for various time intervals, the contents of iron of different valencies were determined separately by the IC technique and the change and/or the interchange of among those iron species in preparations was investigated. Iron raw materials are stable, but Fe2+ in Fe3+ source materials was slightly converted to Fe3+ by oxidation. Fe2+ in Fe3+ source raw materials and Fe3+ in Fe2+ raw materials are determined as impurities. Therefore, IC technique is found to be an appropriate method for comparative evaluation of dissimilar bioavailability of Fe2+ and Fe3+, stability of Fe2+ and Fe3+ raw materials and preparations.