Interrelations between plasma homocysteine and intracellular S-adenosylhomocysteine

S-Adenosylhomocysteine, a potent intracellular methylation inhibitor, is suggested as a potential mediator for hyperhomocysteinemia-related vascular changes. We investigated the effect of acute and chronic hyperhomocysteinemia on intracellular S-adenosylhomocysteine and S-adenosylmethionine in rats and humans. Elevated plasma homocysteine in rats infused with homocysteine produced an increase in S-adenosylhomocysteine (P < 0.001) but not S-adenosylmethionine levels (P > 0.05) in various rat tissues. However intraerythrocyte S-adenosylhomocysteine and S-adenosylmethionine levels were not changed in homocysteine-infused rats and human subjects with experimentally acute hyperhomocysteinemia by methionine loading test. In contrast, erythrocyte S-adenosylhomocysteine levels were significantly higher in chronic renal failure patients, who had chronically elevated plasma homocysteine levels, than in either vascular disease patients or healthy controls (P < 0.05). In conclusion, acute hyperhomocysteinemia can increase intracellular S-adenosylhomocysteine levels in tissues actively involved in homocysteine metabolism. The findings are relevant to homocysteine-related endothelial dysfunction since S-adenosylhomocysteine modulates endothelial cell apoptosis.

[Microsurgical treatment of medially located tumors of the middle skull base]

OBJECTIVE

To report the results of microsurgical treatment of tumors medially located in the middle skull base.

METHODS

The preoperative MRI features, operative approaches, results of operation and postoperative complications in 26 cases were reviewed.

RESULTS

Total resection of the tumors was achieved in 12 cases, subtotal resection in 9 cases, partial resection in 6 cases. Two patients died of operation. Cranial nerve palsy remained unchanged in 5 cases and became exacerbated in 5 cases. Clinical improvement was observed in 15 cases.

CONCLUSION

The combined frontotemporal-zygomatic approach to remove medially located tumors of the middle skull base is adequate.

The catalytic subunit of telomerase is expressed in developing brain neurons and serves a cell survival-promoting function

Telomerase, a specialized reverse transcriptase (RT) linked to cell immortalization and cancer, has been thought not to be expressed in postmitotic cells. We now report that telomerase activity and its essential catalytic subunit, telomerase reverse transcriptase (TERT), are expressed in neurons in the brains of rodents during embryonic and early postnatal development, and are subsequently downregulated. Suppression of TERT expression in cultured embryonic hippocampal neurons increases their vulnerability to apoptosis and excitotoxicity. Overexpression of TERT in PC12 cells suppresses apoptosis induced by trophic factor withdrawal. TERT exerts its anti-apoptotic action at an early stage of the cell death process prior to mitochondrial dysfunction and caspase activation. TERT may serve a neuron survival-promoting function in the developing brain, and downregulation of TERT in the adult brain may contribute to increased neuronal vulnerability in various age-related neurodegenerative disorders.

[Assessment of extracranial internal carotid artery stenosis by duplex scanning magnetic resonance angiography and digital subtraction angiography: a comparative study]

OBJECTIVE

To investigate the correlation between duplex scanning, magnetic resonance angiography (MRA), and digital subtraction angiography (DSA) in the evaluation of extracranial internal carotid artery (EICA) stenosis.

METHODS

All the examinations mentioned-above were performed on 32 patients. According to NASCET, EICA stenosis were classified into four grades: mild (the diameter reduction < 30%), moderate (31% approximately 69%), severe (70% approximately 99%), and total occlusion.

RESULTS

One (3.1%) patient suffered from acute brain infarction after DSA. To compare duplex with DSA, Kappa = 0.78, and by the use of a severe or a greater than 30% stenosis as a positive study, the sensitivity, specificity and accuracy were 78%, 95%, 92% and 97%, 91%, 94%, respectively. To compare MRA with DSA, Kappa = 0.73, and with the same criteria, the sensitivity, specificity and accuracy were 78%, 90%, 89% and 97%, 91%, 94%, respectively. In the evaluation where the results of duplex and MRA were in agreement, to compare duplex + MRA with DSA, Kappa = 0.93, and the sensitivity, specificity and accuracy in the diagnosis of severe stenosis were 100%, 95% and 96%, and the accuracy in the diagnosis of > 30% stenosis was 100%.

CONCLUSIONS

There is good correlativity between duplex scanning, MRA and DSA in the examination of EICA stenosis. A combination of duplex and MRA with their results in agreement may ultimately eliminate the need of DSA in the evaluation of EICA stenosis.

[FHIT gene is abnormal in laryngeal carcinoma]

OBJECTIVE

To determine the role of FHIT gene in laryngeal carcinogenesis.

METHODS

Laryngeal cancer cell line Hep-2, HeLa cell line and 80 primary tumors from patients with laryngeal cancer were studied by means of RT-PCR, sequencing and microsatellite analysis.

RESULTS

Abnormal transcripts of FHIT gene were found in the two cell lines and 70% (14/20) of primary laryngeal carcinomas. Aberrant laryngeal tumor transcripts often lack more than two exons of FHIT gene. Microsatellite analysis showed that both loss of heterozygosity and microsatellite instability of FHIT gene existed in laryngeal carcinoma and the former was more common.

CONCLUSION

FHIT gene participates in the laryngeal carcinogenesis and may be one of the candidate tumor suppressor genes.

Characterization of the block in replication of nucleocapsid protein zinc finger mutants from moloney murine leukemia virus

Mutagenesis studies have shown that retroviral nucleocapsid (NC) protein Zn(2+) fingers (-Cys-X(2)-Cys-X(4)-His-X(4)-Cys- [CCHC]) perform multiple functions in the virus life cycle. Moloney murine leukemia virus mutants His 34-->Cys (CCCC) and Cys 39-->His (CCHH) were able to package their genomes normally but were replication defective. Thermal dissociation experiments showed that the CCHH mutant was not defective in genomic RNA dimer structure. Primer tRNA placement on the viral genome and the ability of the tRNA to function in reverse transcription initiation in vitro also appear normal. Some "full-length" DNA copies of the viral genome were synthesized in mutant virus-infected cells. The CCCC and CCHH mutants produced these DNA copies at greatly reduced levels. Circle junction fragments, amplified from two-long-terminal-repeat viral DNA (vDNA) by PCR, were cloned and characterized. Remarkably, it was discovered that vDNA isolated from cells infected with mutant virions had a wide variety of abnormalities at the site at which the two ends of the linear precursor had been ligated to form the circle (i.e., the junction between the 5' end of U3 and the 3' end of U5). In some molecules, bases were missing from regions corresponding to the U3 and U5 linear vDNA termini; in others, the viral sequences extended either beyond the U5 sequences into the primer-binding site and 5' leader or beyond the U3 sequences into the polypurine tract into the env coding region. Still other molecules contained nonviral sequences between the linear vDNA termini. Such defective genomes would certainly be unsuitable substrates for integration. Thus, strict conservation of the CCHC structure in NC is required for infection events prior to and possibly including integration.

[Antibiotic resistance and plasmid profiles of Vibrio isolates from cultured Sparus sarba]

A total of 51 potential pathogenic vibrios were isolated from moribund silver seabream Sparus sarba, which were collected from local fish farms of Hong Kong. All the isolates were classified and identified as 7 species by the API 20 E system and the scheme of Alsina & Blanch. These species were Vibrio alginolyticus (24 strains), Vibrio vulnificus (12 strains), Vibrio parahaemolyticus(7 strains), Vibrio logei(4 strains), Vibrio pelagius II(2 strains), Vibrio fluvialis (1 strains) and Vibrio meditterranei (1 strains). Among these isolates, the three predominant species (V. alginolyticus, V. vulnificus and V. parahaemolyticus) were confirmed to be virulent to sea bream by experimental challenge. All isolates were also screened for plasmid DNA by agarose gel electrophoresis and tested for susceptibility to 16 antimicrobial agents by the agar dilution method. Of the 51 isolates examined, all strains were sensitive to ceftriaxone, streptomycin, nalidixic acid and rifampicin, and almost all were sensitive to ceftazidime, netilimicin, chloramphenicol and sulfamethoxazole except one or two strains. Most isolates were resistant to ampicillin (60. 8%), cefuroxime (66.7%), amikacin(55%), kanamycin(58.8%) and trimethoprinm (76.5%). Fifteen of the 51 isolates harboured 1-4 plasmids, with sizes ranging from 9 to 123 kb. Both the plasmids and the associated antimicrobial resistance (ampicillin, cefuroxime and trimethoprim) of 9 isolates could be transferred to recipient by single-step conjugation, however, the frequencies were very low, ranging from 10(-11) to 10(-9). The present results indicate that resistance to these antibiotics is chromosomal.

[The detection and clinical significance of telomerase activity in supraglottic carcinomas]

OBJECTIVE

To study the expression and significance of telomerase activity in laryngeal carcinoma.

METHOD

We detected telomerase activity of HEP-2 cell line, 26 cases of supraglottic carcinoma tissues and 15 cases of peri-carcinoma tissues with PCR-based assay designated TRAP (for telomeric repeat amplification protocol).

RESULT

The telomerase positive rate of supraglottic carcinoma 84.6% (22/26) was obvious higher than that of peri-carcinoma 40% (6/15), P < 0.01. No significant differences in positive rates were found among different groups divided according to clinical stage or metastasis of cervical lymph node, P > 0.05.

CONCLUSION

Telomerase activation is related to immortalization process, though not much helpful in diagnosis of supraglottic carcinoma.

[FHIT gene is abnormal in Chinese lung cancers]

OBJECTIVE

To determine whether the FHIT gene at 3p14.2 is abnormal in Chinese lung cancers.

METHODS

Matched normal and cancerous tissues from 21 cases of primary pulmonary squamous cell carcinoma (SQC) and 10 cases of adenocarcinoma (ADC) were obtained immediately after surgery. Total RNA was extracted and the FHIT gene was detected by RT-PCR and DNA sequencing technology.

RESULTS

Normal-sized FHIT transcript was detected in all 31 cases of normal matched tissues. Aberrant transcripts were observed in 15 (48%) of 31 cases of cancerous tissues, 57% (12/21) in SQC and 33% (3/10) in ADC, respectively. All the abnormal transcripts observed lacked exon 5, the first coding exon. The sequence analyses of the aberrant cDNAs revealed deletions of various regions between exon 4 and 10. A synonymous mutation in E8, codon98CAT(H)-->CAC(H), was found in a SQC.

CONCLUSION

The high deletion rate of the FHIT gene in Chinese lung cancer supports the hypothesis that the FHIT gene alteration is involved in tumorigenic development of human neoplasm.

[Shi Ji Yao Yu, the earliest extant monograph on TCM nursery]

Nursery of traditional Chinese medicine (NTCM) has a long history. However, due to the change and influence of the era, society, life style, and many other factors, NTCM did not become an independent discipline for a long period. Although there have been many articles about NTCM appearing in various historical books of traditional Chinese medicine, books specializing on NTCM were not available until later. The earliest ancient book, which is still currently available, describing NTCM in details is the "Shi Ji Yao Yu" written by Qian Xiang in the Qing Dynasty. The book explains the key issues of taking care of a patient's emotional well-being, life style, diet, illness, and drug administration which are of great practical significance now and for the future.

Superoxide mediates the cell-death-enhancing action of presenilin-1 mutations

The mechanism whereby mutations in the presenilin-1 (PS-1) gene on chromosome 14 cause early-onset inherited Alzheimer's disease are unknown. We report that PC6 neural cells (a subclone of PC12 cells) expressing PS-1 mutations (M146V and L286V) exhibit increased superoxide production, nitrotyrosine accumulation, and membrane lipid peroxidation following exposure to amyloid beta-peptide 1-42 (Abeta). Mitochondrial calcium accumulation and membrane depolarization following exposure to Abeta were enhanced in cells expressing mutant PS-1. Overexpression of mitochondrial Mn-SOD greatly reduced superoxide production, nitrotyrosine formation, membrane lipid peroxidation, intramitochondrial calcium accumulation, and membrane depolarization following exposure to Abeta and conferred resistance to the apoptosis-enhancing action of the PS-1 mutations. Nitric oxide synthase inhibitors and the peroxynitrite scavenger uric acid blocked the apoptosis-enhancing action of PS-1 mutations. The data suggest pivotal roles for superoxide production and resulting peroxynitrite formation in the pathogenic mechanism of PS-1 mutations.

Spread of drug-resistant Streptococcus pneumoniae in Asian countries: Asian Network for Surveillance of Resistant Pathogens (ANSORP) Study

Antimicrobial susceptibility of 996 isolates of Streptococcus pneumoniae from clinical specimens was investigated in 11 Asian countries from September 1996 to June 1997. Korea had the greatest frequency of nonsusceptible strains to penicillin with 79.7%, followed by Japan (65.3%), Vietnam (60.8%), Thailand (57.9%), Sri Lanka (41.2%), Taiwan (38.7%), Singapore (23.1%), Indonesia (21.0%), China (9.8%), Malaysia (9.0%), and India (3.8%). Serotypes 23F and 19F were the most common. Pulsed-field gel electrophoresis (PFGE) of 154 isolates from Asian countries showed several major PFGE patterns. The serotype 23F Spanish clone shared the same PFGE pattern with strains from Korea, Japan, Singapore, Taiwan, Thailand, and Malaysia. Fingerprinting analysis of pbp1a, pbp2x, and pbp2b genes of 12 strains from six countries also showed identical fingerprints of penicillin-binding protein genes in most strains. These data suggest the possible introduction and spread of international epidemic clones into Asian countries and the increasing problems of pneumococcal drug resistance in Asian countries for the first time.

An essential role for the Drosophila Pax2 homolog in the differentiation of adult sensory organs

The adult peripheral nervous system of Drosophila includes a complex array of mechanosensory organs (bristles) that cover much of the body surface of the fly. The four cells (shaft, socket, sheath, and neuron) which compose each of these organs adopt distinct fates as a result of cell-cell signaling via the Notch (N) pathway. However, the specific mechanisms by which these cells execute their conferred fates are not well understood. Here we show that D-Pax2, the Drosophila homolog of the vertebrate Pax2 gene, has an essential role in the differentiation of the shaft cell. In flies bearing strong loss-of-function mutations in the shaven function of D-Pax2, shaft structures specifically fail to develop. Consistent with this, we find that D-Pax2 protein is expressed in all cells of the bristle lineage during the mitotic (cell fate specification) phase of bristle development, but becomes sharply restricted to the shaft and sheath cells in the post-mitotic (differentiative) phase. Two lines of evidence described here indicate that D-Pax2 expression and function is at least in part downstream of cell fate specification mechanisms such as N signaling. First, we find that the lack of late D-Pax2 expression in the socket cell (the sister of the shaft cell) is controlled by N pathway activity; second, we find that loss of D-Pax2 function is epistatic to the socket-to-shaft cell fate transformation caused by reduced N signaling. Finally, we show that misexpression of D-Pax2 is sufficient to induce the production of ectopic shaft structures. From these results, we propose that D-Pax2 is a high-level transcriptional regulator of the shaft cell differentiation program, and acts downstream of the N signaling pathway as a specific link between cell fate determination and cell differentiation in the bristle lineage.

Joint action of two RNA degradation pathways controls the timing of maternal transcript elimination at the midblastula transition in Drosophila melanogaster

Maternally synthesized RNAs program early embryonic development in many animals. These RNAs are degraded rapidly by the midblastula transition (MBT), allowing genetic control of development to pass to zygotically synthesized transcripts. Here we show that in the early embryo of Drosophila melanogaster, there are two independent RNA degradation pathways, either of which is sufficient for transcript elimination. However, only the concerted action of both pathways leads to elimination of transcripts with the correct timing, at the MBT. The first pathway is maternally encoded, is targeted to specific classes of mRNAs through cis-acting elements in the 3'-untranslated region and is conserved in Xenopus laevis. The second pathway is activated 2 h after fertilization and functions together with the maternal pathway to ensure that transcripts are degraded by the MBT.

Use of the cuffed oropharyngeal airway as an alternative to the laryngeal mask airway with positive-pressure ventilation

BACKGROUND

The cuffed oropharyngeal airway is a modified Guedel-type oral airway with a cuff at its distal end. The objectives of this study were to compare the ability of the cuffed oropharyngeal airway and the laryngeal mask airway to provide positive-pressure ventilation during general anesthesia, and to assess their relative ease of use and ability to reduce total fresh gas flow rates.

METHODS

In this prospective, randomized study, a cuffed oropharyngeal airway (n = 25) or a laryngeal mask airway (n = 25) device was inserted after induction of anesthesia intravenously using 2 mg/kg propofol. While anesthesia was maintained with sevoflurane and nitrous oxide, the leak pressure, leak fraction (the fractional difference between the inspired and expired tidal volume), minimum fresh gas flow rate, and need for airway manipulations were determined. The anesthesia provider who inserted the device completed an evaluation form at the end of the 15-min study period.

RESULTS

Positive-pressure ventilation was established successfully on the first attempt in 92% of the patients when the cuffed oropharyngeal airway was used and in 88% of the patients when the laryngeal mask airway device was used. However, manipulations of the airway device were necessary more frequently (8 vs. 1 patient; P < 0.05) and the leak pressure was less (22 +/- 6 cm water vs. 26 +/- 5 cm water; P < 0.05) with the cuffed oropharyngeal airway than with the laryngeal mask airway. In addition, the leak fraction (0.19 +/- 0.18 vs. 0.31 +/- 0.22; P < 0.05) and the minimum fresh gas flow rate (1.3 +/- 1.5 vs. 2.4 +/- 2.5; P = 0.12) were less in the laryngeal mask airway group.

CONCLUSIONS

Positive-pressure ventilation is possible with the laryngeal mask airway and cuffed oropharyngeal airway devices. Although the cuffed oropharyngeal airway can be inserted easily by inexperienced users with a high first-attempt success rate (> 90%), manipulations of the device may be required to maintain a patent airway. The laryngeal mask airway device allows positive-pressure ventilation at slightly greater peak inspiratory pressures.

The effect of environmental conditions and glucose feeding in shaking flask on glutathione (GSH) production

The effects of pH, broth volume, initial sugar concentration, ratio of carbon to nitrogen and phosphorus, and the glucose feeding method on GSH production in a shaking flask were investigated. The results showed that the proper pH and broth content for GSH production were 6.0 and 60 ml broth per 500 ml flask, respectively. The initial glucose concentration distinctly affected the GSH production; the intracellular GSH content of yeast would decrease when the initial glucose concentration was beyond 12 g/L. A glucose feeding strategy with the purpose of controlling the specific growth rate at an expected value was developed and applied to a 12 hour fermentation with the total glucose concentration 26.2 g/L; the final cell concentration (DCW) and the intracellular GSH content could reach 8.78 g/L and 13.6 mg/g, respectively, while the total GSH in the broth was 119.4 mg/L and the yield of cell to glucose was 0.335 g/g.

Degradation of pinene by Bacillus pallidus BR425

An aerobic thermophile has been isolated from an alpha-pinene enrichment culture. The isolate, which was designated BR425, has been tentatively identified as Bacillus pallidus using 16S ribosomal RNA gene sequencing and organism morphology. Monophasic and biphasic incubations of BR425 cells with alpha-pinene, beta-pinene, and limonene yielded a number of oxidized monoterpene metabolites with carveol as a common metabolite. A pinene degradation pathway with carveol and carvone as central metabolic intermediates is suggested.

[Loss of heterozygosity and microsatellite instability in laryngeal carcinoma near p16 gene]

OBJECTIVE

To search for the minimal overlap region of tumor suppressor gene in laryngeal carcinoma and discuss the correlation of p16 gene with laryngeal carcinogenesis.

METHODS

Five microsatellite polymorphism markers near p16 gene were selected to detect loss of heterozygosity (LOH) and microsatellite instability (MI) in 60 cases of laryngeal squamous cell carcinoma.

RESULTS

The frequencies of LOH in 5 markers were less than 23.1%, while the frequencies of MI in 2 markers were higher, with the highest frequency (46.1%) in D9S1752.

CONCLUSION

The results suggest that the deletion of p16 gene does not play an important role in the laryngeal carcinogenesis and there may exist a gene around D9S1752 participating in the development of laryngeal carcinoma, which correlates with the mutation of repair gene.

Anti-apoptotic role of telomerase in pheochromocytoma cells

Telomerase is a protein-RNA enzyme complex that adds a six-base DNA sequence (TTAGGG) to the ends of chromosomes and thereby prevents their shortening. Reduced telomerase activity is associated with cell differentiation and accelerated cellular senescence, whereas increased telomerase activity is associated with cell transformation and immortalization. Because many types of cancer have been associated with reduced apoptosis, whereas cell differentiation and senescence have been associated with increased apoptosis, we tested the hypothesis that telomerase activity is mechanistically involved in the regulation of apoptosis. Levels of telomerase activity in cultured pheochromocytoma cells decreased prior to cell death in cells undergoing apoptosis. Treatment of cells with the oligodeoxynucleotide TTAGGG or with 3,3'-diethyloxadicarbocyanine, agents that inhibit telomerase activity in a concentration-dependent manner, significantly enhanced mitochondrial dysfunction and apoptosis induced by staurosporine, Fe2+ (an oxidative insult), and amyloid beta-peptide (a cytotoxic peptide linked to neuronal apoptosis in Alzheimer's disease). Overexpression of Bcl-2 and the caspase inhibitor zVAD-fmk protected cells against apoptosis in the presence of telomerase inhibitors, suggesting a site of action of telomerase prior to caspase activation and mitochondrial dysfunction. Telomerase activity decreased in cells during the process of nerve growth factor-induced differentiation, and such differentiated cells exhibited increased sensitivity to apoptosis. Our data establish a role for telomerase in suppressing apoptotic signaling cascades and suggest a mechanism whereby telomerase may suppress cellular senescence and promote tumor formation.

Homocysteine enhances neutrophil-endothelial interactions in both cultured human cells and rats In vivo

Despite intense investigation, mechanisms linking the development of occlusive vascular disease with elevated levels of homocysteine (HCY) are still unclear. The vascular endothelium plays a key role in regulating thrombogenesis and thrombolysis. We hypothesized that vascular lesions in individuals with elevated plasma HCY may be related to a dysfunction of the endothelium triggered by HCY. We investigated the effect of HCY on human neutrophil adhesion to and migration through endothelial monolayers. We also examined the effect of HCY on leukocyte adhesion and migration in mesenteric venules of anesthetized rats. We found that pathophysiological concentrations of HCY in vitro induce increased adhesion between neutrophils and endothelial cells. This contact results in neutrophil migration across the endothelial layer, with concurrent damage and detachment of endothelial cells. In vivo, HCY infused in anesthetized rats caused parallel effects, increasing leukocyte adhesion to and extravasation from mesenteric venules. Our results suggest that extracellular H2O2, generated by adherent neutrophils and/or endothelial cells, is involved in the in vitro endothelial cell damage. The possibility exists that leukocyte-mediated changes in endothelial integrity and function may lead to the vascular disease seen in individuals with elevated plasma HCY.

The dominant mutation Glazed is a gain-of-function allele of wingless that, similar to loss of APC, interferes with normal eye development

Dominant mutations have served as invaluable tools for Drosophila geneticists. Here we analyze the dominant eye mutation Glazed (Gla) that was described by T. H. Morgan more than 50 years ago. We show that Gla causes the loss of photoreceptor cells during pupal stages, in a process reminiscent of apoptosis, with a concomitant overproduction of eye pigment. This phenotype is very similar to that caused by the loss of D-APC, a negative regulator of Wingless (Wg) signal transduction. Genetic analyses reveal however that the Gla gain-of-function phenotype can be reverted to wild-type. By generating a P-element-induced revertant of Gla we demonstrate that Gla is allelic to wg. The molecular lesion in Gla indicates that the insertion of a roo retrotransposon leads to ectopic expression of wg during pupal stages. We show that the Gla phenotype is similar to that caused by ectopic expression of Wg driven by the sevenless (sev) enhancer. In both cases Wg exerts its effect, at least in part, by negatively regulating the expression of the Pax2 homolog sparkling (spa). Gla represents not only the first dominant allele of wg, but it may also be the first allele ever described for wg.

Dexmedetomidine failed to block the acute hyperdynamic response to electroconvulsive therapy

BACKGROUND

Orally administered clonidine (0.2-0.3 mg) has been reported to decrease the acute hypertensive response to electroconvulsive therapy (ECT) without prolonging early recovery. This preliminary study was designed to evaluate the acute hemodynamic effects of the investigational alpha2-adrenergic agonist, dexmedetomidine, in patients undergoing a series of ECT treatments.

METHODS

Six patients undergoing a series of three to six consecutive ECT treatments were studied according to a randomized, double-blind, placebo-controlled protocol All patients received either saline or dexmedetomidine, 0.5 or 1.0 microg/kg intravenously, 10-30 min before induction of anesthesia for ECT using a standardized anesthesia protocol. In addition to assessing the cardiovascular variables, the duration of seizure activity, degree of sedation, and time to discharge from the Phase I recovery unit were assessed.

RESULTS

Although dexmedetomidine produced dose-related increases in the level of sedation before the ECT procedure, it failed to decrease the peak blood pressure and heart rate responses after the ECT treatment. The 0.5 and 1.0 microg/kg doses of dexmedetomidine prolonged the times to orientation and to discharge from the Phase I unit.

CONCLUSIONS

The results of this pilot study suggest that dexmedetomidine (0.5-1.0 microg/kg given intravenously) is not beneficial in controlling the acute hyperdynamic response after ECT.

The endoplasmic reticulum stress-responsive protein GRP78 protects neurons against excitotoxicity and apoptosis: suppression of oxidative stress and stabilization of calcium homeostasis

The 78-kDa glucose-regulated protein (GRP78) is localized in the endoplasmic reticulum (ER), and its expression is increased by environmental stressors in many types of nonneuronal cells. We report that levels of GRP78 are increased in cultured rat hippocampal neurons exposed to glutamate and oxidative insults (Fe2+ and amyloid beta-peptide) and that treatment of cultures with a GRP78 antisense oligodeoxynucleotide increases neuronal death following exposure to each insult. GRP78 antisense treatment enhanced apoptosis of differentiated PC12 cells following NGF withdrawal or exposure to staurosporine. Pretreatment of hippocampal cells with 2-deoxy-d-glucose, a potent inducer of GRP78 expression, protected neurons against excitotoxic and oxidative injury. GRP78 expression may function to suppress oxidative stress and stabilize calcium homeostasis because treatment with GRP78 antisense resulted in increased levels of reactive oxygen species and intracellular calcium following exposure to glutamate and oxidative insults in hippocampal neurons. Dantrolene (a blocker of ER calcium release), uric acid (an antioxidant), and zVAD-fmk (a caspase inhibitor) each protected neurons against the death-enhancing action of GRP78 antisense. The data suggest that ER stress plays a role in neuronal cell death induced by an array of insults and that GRP78 serves a neuroprotective function.

[Pathogenetic effect of platelet activating factor on enterogenic endotoxemia after burn]

OBJECTIVE

To investigate the effects of platelet activating factor (PAF) on the occurrence of enterogenic endotoxemia after burn.

METHODS

The relationship between changes of PAF and enterogenic endotoxima was observed on a model of rats with 30% TBSA III degree burn.

RESULTS

The intestinal permeability and plasma endotoxin were significantly elevated and were positively correlated with the increase of PAF in the intestinal tissue and blood. PAF antagonist treatment significantly decreased the intestinal permeability and the levels of plasma endotoxin. After intravenous injection of enogenous PAF to healthy rats, the intestinal permeability and plasma endotoxin were also markedly increased, which was significantly depended on the dose of PAF.

CONCLUSION

PAF is one of the important factors for the occurrence of postburn enterogenic endotoximia.