Single nucleotide polymorphisms in the CDH17 gene of colorectal carcinoma

AIM: To investigate the relationship between c.343A>G and c.2216A>C polymorphism sites in the CDH17 gene and colorectal carcinoma.

METHODS: Ninety-three non-consanguineous colorectal carcinoma patients admitted to the Department of Oncology at the First Affiliated Hospital of Zhengzhou University were included in this study. Ninety-three peripheral venous blood samples, of approximately one milliliter from each patient, were collected between December 2009 and August 2010. The genomic DNA of these peripheral venous blood samples were extracted and purified using a Fermentas Genomic DNA Purification Kit (Fermentas, CA) according to the manufacturer’s protocol. The single nucleotide polymorphisms (SNPs) of the liver-intestine cadherin (CDH17) gene c.343A>G and c.2216A>C were determined by the polymerase chain reaction-single strand conformation polymorphism method (PCR-SSCP) in 93 peripheral venous blood samples from patients suffering with colorectal carcinoma. Typical samples that showed different migration bands in SSCP were confirmed by sequencing. Directed DNA sequencing was used to check the correctness of the genotype results from the PCR-SSCP method.

RESULTS: There was a significant association between the c.2216 A>C SNPs of the CDH17 gene and the tumor-node-metastasis (TNM) grade, as well as with lymph node status, in 93 peripheral venous blood samples from colorectal carcinoma patients. The genotype frequencies of A/C, A/A, and C/C were 12.90%, 33.33% and 53.76%, respectively. There was a significant correlation between lymph node metastasis, TNM grade, and the genotype distribution (P < 0.05). The C/C genotype raised the risk of lymph node metastasis and the TNM grade. There was a significant difference in the TNM grade and lymph node metastasis between the A/A and C/C genotypes (P = 0.003 and P = 0.013, respectively). Patients with colorectal carcinoma carrying the C allele tended to have a higher risk of lymph node metastasis and have a higher TNM grade. The difference between the TNM grades, as well as the lymph node metastasis of the two alleles, was statistically significant (P < 0.01).

CONCLUSION: The SNPs of the CDH17 gene c.2216 A>C might be clinically important in the prognosis of colorectal carcinoma.

Spatial-temporal analysis of malaria and the effect of environmental factors on its incidence in Yongcheng, China, 2006-2010

Background

In 2003, Plasmodium vivax malaria has re-emerged in central eastern China including Yongcheng prefecture, Henan Province, where no case has been reported for eleven years. Our goals were to detect the space-time distribution pattern of malaria and to determine significant environmental variables contributing to malaria incidence in Yongcheng from 2006 to 2010, thus providing scientific basis for further optimizing current malaria surveillance and control programs.

Methods

This study examined the spatial and temporal heterogeneities in the risk of malaria and the influencing factors on malaria incidence using geographical information system (GIS) and time series analysis. Univariate analysis was conducted to estimate the crude correlations between malaria incidence and environmental variables, such as mosquito abundance and climatic factors. Multivariate analysis was implemented to construct predictive models to explore the principal environmental determinants on malaria epidemic using a Generalized Estimating Equation (GEE) approach.

Results

Annual malaria incidence at town-level decreased from the north to south, and monthly incidence at prefecture-level demonstrated a strong seasonal pattern with a peak from July to November. Yearly malaria incidence had a visual spatial association with yearly average temperature. Moreover, the best-fit temporal model (model 2) (QIC = 16.934, P<0.001, R² = 0.818) indicated that significant factors contributing to malaria incidence were maximum temperature at one month lag, average humidity at one month lag, and malaria incidence of the previous month.

Conclusions

Findings supported the effects of environment factors on malaria incidence and indicated that malaria control targets should vary with intensity of malaria incidence, with more public resource allocated to control the source of infections instead of large scale An. sinensis control when malaria incidence was at a low level, which would benefit for optimizing the malaria surveillance project in China and some other countries with unstable or low malaria transmission.

Neuronal excitability and calcium/calmodulin-dependent protein kinase type II: location, location, location

Calcium/calmodulin-dependent protein kinase type II (CaMKII) is a highly abundant serine/threonine kinase comprising a significant fraction of total protein in mammalian forebrain and forming a major component of the postsynaptic density. CaMKII is essential for certain forms of synaptic plasticity and memory consolidation and this is mediated through substrate binding and intramolecular phosphorylation of holoenzyme subunits. CaMKII is multifunctional; it targets a variety of cellular substrates, and this diversity depends on holoenzyme subunit composition. CaMKII comprises homooligomeric and heterooligomeric complexes generated from four subunits (α, β, δ, and γ) encoded by separate genes that are further expanded by extensive alternative splicing to more than 30 different isoforms. Much attention has been paid to understanding the regulation of CaMKII function through its structural diversity and/or substrate specificity. However, given the importance of subunit composition to holoenzyme activity, it is likely that specificity of cellular expression of CaMKII isoforms also plays a major role in regulation of enzyme function. Herein we review the cellular colocalization of CaMKII isoforms with special regard to the cell-type specificity of isoform expression in brain. In addition, we highlight the remarkable specificity of subcellular localization by the CaMKIIα isoform. In addition, we discuss the role that this cellular specificity of expression might play in propagating the type of recurrent neuronal activity associated with disorders such as temporal lobe epilepsy.

Systematic review and meta-analysis of outcomes after intraoperative pancreatic duct stent placement during pancreaticoduodenectomy

BACKGROUND

Postoperative pancreatic leakage after pancreaticoduodenectomy is often serious. Although some studies have suggested that stenting the anastomosis can reduce the incidence of this complication, the value of stenting in the setting of pancreaticoduodenectomy remains unclear.

METHODS

Studies comparing outcomes of stent versus no stent, and internal versus external stent placement for pancreaticoduodenectomy were eligible for inclusion. Pooled odds ratios (ORs) with 95 per cent confidence intervals were calculated using fixed- or random-effects models.

RESULTS

From a search of the literature published between January 1973 and September 2011, five randomized clinical trials (RCTs) and 11 non-randomized observational clinical studies (OCS) involving 1726 patients were selected for inclusion in this review. Meta-analysis of RCTs revealed that placing a stent in the pancreatic duct did not reduce the incidence of postoperative pancreatic fistula. External stents had no advantage over internal stents in terms of clinical outcome. Subgroup analyses revealed that use of an external stent significantly reduced the incidence of pancreatic fistula (RCTs: OR 0·42, 0·24 to 0·76, P = 0·004; OCS: OR 0·43, 0·27 to 0·68, P < 0·001), delayed gastric emptying (RCTs: OR 0·41, 0·19 to 0·87, P = 0·02) and postoperative morbidity (RCTs: OR 0·55, 0·34 to 0·89, P = 0·02) compared with no stent.

CONCLUSION

Pancreatic duct stenting did not reduce the incidence of pancreatic fistula and other complications in pancreaticoduodenectomy compared with no stenting. Although no difference was found between external and internal stents in terms of efficacy, external stents seemed to reduce the incidence of pancreatic fistula compared with control.

Random repeated cross sectional study on breeding site characterization of Anopheles sinensis larvae in distinct villages of Yongcheng City, People's Republic of China

BACKGROUND

Characterizing the breeding site of Anopheles sinensis is of major importance for the transition from malaria control to elimination in China. However, little information is available especially regarding the characteristics and influencing factors of breeding sites of An. sinensis in Yongcheng City, a representative region of unstable malaria transmission in the Huang-Huai River region of central China. The aims of this study were to determine the breeding site characteristics of An. sinensis and related environmental and physicochemical parameters, to find out which breeding site characteristics could best explain the presence of An. sinensis larvae, and to determine whether the breeding habit of An. sinensis has changed or not.

METHODS

Random repeated cross sectional study was undertaken in six villages of the Yongcheng city characterized by different levels of the historical incidence of P. vivax malaria. The potential breeding sites of An. sinensis larvae in each village were examined twice per month both in the household courtyards and the village surroundings. The larval sampling was done by the standard dipping method. Some important breeding site characterizations were recorded and characterized. The anopheline mosquito larvae and emerged adults were identified to the species level morphologically and to sub-species by the ribosomal DNA PCR technique. Chi-square analysis and logistic regression analysis were applied to determine the importance of factors for explaining the presence or absence of An. sinensis larvae.

RESULTS

According to the ribosomal DNA PCR assay, all sampled anopheline mosquito larvae and emerged adults belonged to An. sinensis. Only 3 containers that were sampled from the household courtyards were found to contain An. sinensis larvae. There were no differences in the species composition of mosquito larvae among containers that contained water in the household courtyards (P > 0.05). An. sinensis larvae were shown to be present in a total of 60 breeding sites in the village surroundings, this included 8 (13.3%) river fringes, 26 (43.3%) ponds, 23 (38.3%) puddles, and 3 (5.0%) irrigation/drainage ditches. Logistic regression analysis revealed that the breeding site type, water depth, chemical oxygen demand (COD), ammonia nitrogen, and sulphate were found to be the key factors determining the presence of An. sinensis larvae. Approximately 94.9% of An. sinensis larvae inhabited relatively large and medium-sized water bodies, with depths between 0.5 m and 1.0 m (73.3%), COD lower than 2 mg/L (75%), ammonia nitrogen lower than 0.4 mg/L (86.7%), and sulphate lower than 150 mg/L (58.3%), respectively.

CONCLUSION

These results indicate that the majority of An. sinensis larval breeding sites were relatively large and medium-sized water bodies with depths between 0.5 m and 1.0 m, and containing low levels of COD, ammonia nitrogen, and sulphate, respectively. For effective An. sinensis larval control, the type of breeding site, water depth, COD, ammonia nitrogen, and sulphate should be given higher priority over other factors in areas where it is the primary vector.

The abundance and host-seeking behavior of culicine species (Diptera: Culicidae) and Anopheles sinensis in Yongcheng city, People's Republic of China

Background

The knowledge of mosquito species diversity and the level of anthropophily exhibited by each species in a region are of great importance to the integrated vector control. Culicine species are the primary vectors of Japanese encephalitis (JE) virus and filariasis in China. Anopheles sinensis plays a major role in the maintenance of Plasmodium vivax malaria transmission in China. The goal of this study was to compare the abundance and host-seeking behavior of culicine species and An. sinensis in Yongcheng city, a representative region of P. vivax malaria. Specifically, we wished to determine the relative attractiveness of different animal baits versus human bait to culicine species and An. sinensis.

Results

Culex tritaeniorhynchus was the most prevalent mosquito species and An. sinensis was the sole potential vector of P. vivax malaria in Yongcheng city. There were significant differences (P < 0.01) in the abundance of both An. sinensis and Cx. tritaeniorhynchus collected in distinct baited traps. The relative attractiveness of animal versus human bait was similar towards both An. sinensis and Cx. tritaeniorhynchus. The ranking derived from the mean number of mosquitoes per bait indicated that pigs, goats and calves frequently attracted more mosquitoes than the other hosts tested (dogs, humans, and chickens). These trends were similar across all capture nights at three distinct villages. The human blood index (HBI) of female An. sinensis was 2.94% when computed with mixed meals while 3.70% computed with only the single meal. 19:00~21:00 was the primary peak of host-seeking female An. sinensis while 4:00~5:00 was the smaller peak at night. There was significant correlation between the density of female An. sinensis and the average relative humidity (P < 0.05) in Wangshanzhuang village.

Conclusions

Pigs, goats and calves were more attractive to An. sinensis and Cx. tritaeniorhynchus than dogs, humans, and chickens. Female An. sinensis host-seeking activity mainly occurred from 19:00 to 21:00. Thus, we propose that future vector control against An. sinensis and Cx. tritaeniorhynchus in the areas along the Huang-Huai River of central China should target the interface of human activity with domestic animals and adopt before human hosts go to bed at night.

Axon-glia synapses are highly vulnerable to white matter injury in the developing brain

The biology of cerebral white matter injury has been woefully understudied, in part because of the difficulty of reliably modeling this type of injury in rodents. Periventricular leukomalacia (PVL) is the predominant form of brain injury and the most common cause of cerebral palsy in premature infants. PVL is characterized by predominant white matter injury. No specific therapy for PVL is presently available, because the pathogenesis is not well understood. Here we report that two types of mouse PVL models have been created by hypoxia-ischemia with or without systemic coadministration of lipopolysaccharide (LPS). LPS coadministration exacerbated hypoxic-ischemic white matter injury and led to enhanced microglial activation and astrogliosis. Drug trials with the antiinflammatory agent minocycline, the antiexcitotoxic agent NBQX, and the antioxidant agent edaravone showed various degrees of protection in the two models, indicating that excitotoxic, oxidative, and inflammatory forms of injury are involved in the pathogenesis of injury to immature white matter. We then applied immunoelectron microscopy to reveal fine structural changes in the injured white matter and found that synapses between axons and oligodendroglial precursor cells (OPCs) are quickly and profoundly damaged. Hypoxia-ischemia caused a drastic decrease in the number of postsynaptic densities associated with the glutamatergic axon-OPC synapses defined by the expression of vesicular glutamate transporters, vGluT1 and vGluT2, on axon terminals that formed contacts with OPCs in the periventricular white matter, resulted in selective shrinkage of the postsynaptic OPCs contacted by vGluT2 labeled synapses, and led to excitotoxicity mediated by GluR2-lacking, Ca(2+) -permeable AMPA receptors. Overall, the present study provides novel mechanistic insights into the pathogenesis of PVL and reveals that axon-glia synapses are highly vulnerable to white matter injury in the developing brain. More broadly, the study of white matter development and injury has general implications for a variety of neurological diseases, including PVL, stroke, spinal cord injury, and multiple sclerosis.

Low-threshold calcium channel subunit Ca(v) 3.3 is specifically localized in GABAergic neurons of rodent thalamus and cerebral cortex

Relatively little is known about the subcellular localization of low threshold Ca²+ channels (T-channels) in the brain. Using immunocytochemical labeling and preembedding immunoperoxidase and silver-enhanced immunogold electron microscopy, we localized T-channel subunit Ca(v) 3.3 in rodent cerebral cortex and thalamus. Double immunofluorescent staining demonstrated that Ca(v) 3.3-labeled neurons in cerebral cortex are a subgroup of GABAergic interneurons that coexpress calbindin and in half of the cases parvalbumin. In the thalamus, virtually all reticular nucleus (RTN) neurons were immunopositive for Ca(v) 3.3, while neurons in dorsal thalamic nuclei were nonimmunoreactive. At the electron microscopic (EM) level, in cortical layers IV-V and RTN neurons, Ca(v) 3.3 immunoreactivity was mainly associated with membranes of dendrites but with some localization in cytoplasm. None was found in axon terminals. In cortex, ≈73% of immunogold particles were present in close proximity to synaptic contacts (<0.5 μm from the postsynaptic density), while 27% were distributed along membranes at extrasynaptic sites (>0.5 μm from the postsynaptic density). In RTN, ≈57% particles were evenly distributed along perisynaptic membranes and the remaining 43% of particles were diffusely localized at extrasynaptic membranes. The density of particles along the dendritic membranes of cortical neurons was 40% higher than in RTN neurons. These results suggest that Ca(v) 3.3 plays a role in regulating GABAergic neurons whose actions underlie thalamocortical rhythmicity.

[Effect of a simulated He-O2 saturation dive to 65 msw on oxidative stress in humans]

OBJECTIVE

To investigate whether a simulated He-O2 saturation dive to 65 msw would affect oxidative balance in humans.

METHODS

Seven divers participated in a simulated saturation dive to 0.75 MPa (65 msw). 24-h urine samples were collected twice before, twice during, and twice after the dive, then were analyzed for contents of superoxide dismutase (SOD), malondialdehyde (MDA), total amino acid (T-AA) and total anti-oxidant capacity (T-AOC). Meanwhile, total urine volume and body weight were measured.

RESULTS

The content of T-AA was higher. (P < 0.05) than the base value in final decompression, but reverse to normal at one week after decompression. There were no changes in contents of SOD, MDA and T-AOC during and after the dive compared with their basic value. Total urine volume was lower (P < 0.05, vs basic value) at first day in chamber, then returned to normal. Body weight gradually increased after compression till the end of decompression (higher than basic value, P < 0.05).

CONCLUSION

These data indicate that simulated saturation dive to 65 msw may not induce obvious oxidative damage, but it is necessary to monitor 24-h urine volume and oxidative sress by time in order to prevent from tissue injury.

Effect of butyl benzyl phthalate on life table-demography of two successive generations of cladoceran Moina macrocopa Straus

In this study, the acute toxicity of butyl benzyl phthalate (BBP) to freshwater cladoceran Moina macrocopa was tested, and its chronic effects on survival and reproduction of two successive generations of the cladoceran were studied using life-table demographic method. The results showed that the 48-hr LC50 of BBP for M. macrocopa was 3.69 mg l(-1). Compared to the blank controls, BBP at 125, 500, 1000 and 2000 microg l(-1) significantly shortened the life expectancy at birth, BBP at 125-2000 microg l(-1) decreased the net reproductive rate, and BBP at 500 and 1000 microg I(-1) shortened the generation time but increased the intrinsic rate of population increase of the parental M. macrocopa. BBP at 62.5,125, 500,1000 and 2000 microg l(-1) increased the intrinsic rate of population increase of the F1 generation. A significant dose-effect relationship existed between BBP concentration and life expectancy at birth, net reproductive rate as well as intrinsic rate of population increase of the parental M. macrocopa. The parental M. macrocopa were more sensitive in survival, development and reproduction to BBP than the F1 generation, but the reverse was also true in the population growth. Extending chronic toxicity tests to the second generation of M. macrocopa increased the cost-effectiveness of the assays.

Controlling vibrational resonance in a multistable system by time delay

The phenomenon of vibrational resonance in a delayed multistable system that is excited by biharmonic signals is investigated in the present paper. Different from the former theory, the appearance and the disappearance of the vibrational resonance are controlled by adjusting the time delay parameter instead of modulating the amplitude of the high-frequency signal. The motion of the orbit within or between the different potential wells can also be controlled. Furthermore, based on both the methods of numerical simulation and analytical analysis, the behavior of delay-induced multiple vibrational resonance and its mechanism are investigated and discussed. The multiple vibrational resonance, which is quantified by the response amplitude at the low-frequency, is found to be periodic in the delay parameter with two periods, i.e., the periods of the two driven signals. The method used in this paper gives a new way for controlling vibrational resonance in a multistable system.

Distinct mechanism of small-for-size fatty liver graft injury--Wnt4 signaling activates hepatic stellate cells

In this study, we aimed to investigate the significance of hepatic stellate cells (HSCs) activation in small-for-size fatty liver graft injury and to explore the underlying molecular mechanism in a rat liver transplantation model. A rat orthotopic liver transplantation model using fatty grafts (40% of fatty changes) and cirrhotic recipients was applied. Intragraft gene expression profiles, ultrastructure features and HSCs activation were compared among the rats received different types of grafts (whole vs. small-for-size, normal vs. fatty). The distinct molecular signature of small-for-size fatty graft injury was identified by cDNA microarray screening and confirmed by RT-PCR detection. In vitro functional studies were further conducted to investigate the direct effect of specific molecular signature on HSCs activation. HSCs activation was predominantly present in small-for-size fatty grafts during the first 2 weeks after transplantation, and was strongly correlated with progressive hepatic sinusoidal damage and significant upregulation of intragraft Wnt4 signaling pathway. In vitro suppression of Wnt4 expression could inhibit HSC activation directly. In conclusion, upregulation of Wnt4 signaling led to direct HSC activation and subsequently induced small-for-size fatty liver grafts injury. Discovery of this distinct mechanism may lay the foundation for prophylactic treatment for marginal graft injury in living donor liver transplantation.

ERK-MAPK signaling opposes rho-kinase to reduce cardiomyocyte apoptosis in heart ischemic preconditioning

We and others have reported that Rho-kinase plays an important role in the pathogenesis of heart ischemia/reperfusion (I/R) injury. Studies have also demonstrated that the activation of Rho-kinase is reversed in ischemic preconditioning (IPC). However, the mechanisms by which Rho-kinase is increased in I/R and reversed in IPC are not thoroughly understood. In female Wistar rats, we created I/R by ligating the left anterior-descending branch of the coronary artery (LAD) for 30 min and releasing the ligature for 180 min. IPC rats underwent IPC (two cycles of 5-min ligation of the LAD and 5-min reflow) before I/R. IPC caused a significant increase in extracellular signal-regulated kinase (ERK)1/2 activity and reduced Rho-kinase activity and cardiomyocyte apoptosis (P<0.05 versus I/R). Administration of PD98059, an inhibitor of ERK-mitogen-activated protein kinase (MAPK), increased cardiomyocyte apoptosis, Caspase-3 activity and myocardial infarction size (P<0.05 versus IPC). Western-blot analysis showed that administration of PD98059 increased Rho-kinase activity. Treatment with fasudil, an inhibitor of Rho-kinase, reversed cell apoptosis caused by treatment with PD98059 in IPC. In addition, ROCK1 (Rho-kinase 1) may be the major Rho-kinase isoform that is opposed by ERK-MAPK signaling in IPC. These results indicate that ERK-MAPK signaling is required in IPC to oppose Rho-kinase activity in cardiomyocyte apoptosis in vivo.

First-principles calculation on the Curie temperature of Gd(3)NiSi(2)

The electronic structure and magnetic properties for Gd(3)NiSi(2) have been studied theoretically from a first-principles density functional calculation. The energy band structure is calculated in a local spin density approximation (LSDA), and in a LSDA+Hubbard U approach (LSDA+U), respectively. For Gd atoms, in the LSDA+U approximation, seven spin-up 4f bands are fully occupied and situated at the bottom of Si s states, while the spin-down 4f hole levels are completely unoccupied and well above the Fermi level. The calculated magnetic moments for the three Gd sites vary from 7.13 to 7.16 µ(B), leading to a total magnetization of 21.5 µ(B) per formula unit including the small induced moments at Ni and Si atoms. The exchange coupling parameters for the nearest Gd-Gd pairs (J(Gd-Gd)) are 0.16 mRyd, 0.14 mRyd and 0.19 mRyd in the three Gd sub-lattices, respectively. The inter-site distance dependence of J(Gd-Gd) shows a RKKY-like oscillation. The estimated Curie temperature is about 251 K from the calculated exchange coupling parameters based on the mean-field approximation, in good agreement with the experimental value (T(C)(exp.) = 215 K).

[Effects of neregulin on rhesus monkey heart failure induced by rapid pacing]

OBJECTIVE

To investigate the effects of Recombined Human Neuregulin (NRG) on the expression of Glucose transporter (Glut1) in myocardium tissue of Rhesus Monkeys with Pacing-induced Heart Failure and the heart function.

METHODS

Twenty four rhesus monkeys were randomly divided into three groups (shame operated group, heart failure group and NRG treated group), each with 8 monkeys. Heart failures were induced by rapid pacing (240 heart beats/min). Daily intravenous injection of recombined human NRG [3 microg/(kg x d)] and normal saline were given to the monkeys for 10 days for the NRG treated group and heart failure group respectively. Hemodynamic measurements including +dp/dt(max) and left ventricular systolic, end-diastolic blood pressures (LVSP and LVEDP) were conducted. The RT-PCR was applied to detect the expression level of PKB, Glut1 mRNA in the left ventricular cardiac muscle.

RESULTS

The monkeys in the heart failure group had lower levels of + dp/dt(max) and LVSP and higher levels of LVEDP than those in the shame operated group (P < 0.05). The monkeys in the NRG treated group had higher levels of +dp/dt(max) than those in the heart failure group (P < 0.05). Lower expression of PKB, Glut1 mRNA in the heart failure group was observed compared with the shame operated group (P < 0.05) while the NRG treated group had a higher expression level of PKB,Glut1 mRNA by compared with the heart failure group (P < 0.05).

CONCLUSION

Recombined human NRG can relieve heart failure syndroms through up-regulating the expression of PKB, Glut1 mRNA and improving energy supply of the ischemic cardiac muscle.

Dorsal turning of motor corticospinal axons at the pyramidal decussation requires plexin signaling

BACKGROUND

The development of the corticospinal tract (CST) in higher vertebrates relies on a series of axon guidance decisions along its long projection pathway. Several guidance molecules are known to be involved at various decision points to regulate the projection of CST axons. However, previous analyses of the CST guidance defects in mutant mice lacking these molecules have suggested that there are other molecules involved in CST axon guidance that are yet to be identified. In this study, we investigate the role of plexin signaling in the guidance of motor CST axons in vivo.

RESULTS

Expression pattern studies show that plexin-A3, plexin-A4, and neuropilin-1 are expressed in the developing cerebral cortex when the motor CST axons originating from layer V cortical neurons are guided down to the spinal cord. By analyzing mutant mice, we show that motor CST axons that turn dorsally to cross the midline at the pyramidal decussation require plexin-A3 and plexin-A4 signaling. Although other CST guidance defects are found in neuropilin-1 mutants, this dorsal turning defect is not observed in either neuropilin-1 or neuropilin-2 mutants, suggesting that the local cues that activate plexin signaling at the dorsal turning point are membrane-bound semaphorins. Further expression pattern study and mutant analysis indicate that Sema6A is one of the local cues for motor CST axon turning at the pyramidal decussation.

CONCLUSION

Dorsal turning and midline crossing at the pyramidal decussation is a crucial step to properly direct CST axons into the dorsal spinal cord. We show that the signaling of plexin-A3, plexin-A4, and Sema6A is at least partially required for dorsal turning of the CST axons, while neuropilin-1 is required for proper fasciculation of the tract at midline crossing. Together with previous reports, these results demonstrate that several guidance cues are specifically utilized to regulate the dorsal turning and midline crossing of developing CST axons.

[Acute toxicity of DDT and its effects on life table demography of Moina macrocopa]

The 48 h LC50 of DDT to Moina macrocopa was determined by acute toxicity test, and the effects of different concentrations (1, 8, 16, 24, 32 and 40 microg x L(-1)) of DDT on the life table demography of M. macrocopa was studied by life table demography. The results showed that the 48 h LC50 of DDT to M. macrocopa was 324 microg x L(-1). 1-40 microg x L(-1) of DDT had no significant effects on the life expectancy at birth, generation time, net reproductive rate, and gross productive rate of M. macrocopa (P > 0.05), but significantly affected the intrinsic rate of population increase (rm) (P < 0.05). The rm of M. macrocopa increased markedly at 8, 16 and 40 microg x L(-1) of DDT, compared with the blank control, indicating that when the life table demography of M. macrocopa was used to monitor the ecological effects of sublethal concentrations of DDT, rm could be a sensitive indicator.

Reticular nucleus-specific changes in alpha3 subunit protein at GABA synapses in genetically epilepsy-prone rats

Differential composition of GABA(A) receptor (GABA(A)R) subunits underlies the variability of fast inhibitory synaptic transmission; alteration of specific GABA(A)R subunits in localized brain regions may contribute to abnormal brain states such as absence epilepsy. We combined immunocytochemistry and high-resolution ImmunoGold electron microscopy to study cellular and subcellular localization of GABA(A)R alpha1, alpha3, and beta2/beta3 subunits in ventral posterior nucleus (VP) and reticular nucleus (RTN) of control rats and WAG/Rij rats, a genetic model of absence epilepsy. In control rats, alpha1 subunits were prominent at inhibitory synapses in VP and much less prominent in RTN; in contrast, the alpha3 subunit was highly evident at inhibitory synapses in RTN. beta2/beta3 subunits were evenly distributed at inhibitory synapses in both VP and RTN. ImmunoGold particles representing all subunits were concentrated at postsynaptic densities with no extrasynaptic localization. Calculated mean number of particles for alpha1 subunit per postsynaptic density in nonepileptic VP was 6.1 +/- 3.7, for alpha3 subunit in RTN it was 6.6 +/- 3.4, and for beta2/beta3 subunits in VP and RTN the mean numbers were 3.7 +/- 1.3 and 3.5 +/- 1.2, respectively. In WAG/Rij rats, there was a specific loss of alpha3 subunit immunoreactivity at inhibitory synapses in RTN, without reduction in alpha3 subunit mRNA or significant change in immunostaining for other markers of RTN cell identity such as GABA or parvalbumin. alpha3 immunostaining in cortex was unchanged. Subtle, localized changes in GABA(A)R expression acting at highly specific points in the interconnected thalamocortical network lie at the heart of idiopathic generalized epilepsy.

Endocytosis and synaptic removal of NR3A-containing NMDA receptors by PACSIN1/syndapin1

A key step in glutamatergic synapse maturation is the replacement of developmentally expressed N-methyl-D-aspartate receptors (NMDARs) with mature forms that differ in subunit composition, electrophysiological properties and propensity to elicit synaptic plasticity. However, the mechanisms underlying the removal and replacement of synaptic NMDARs are poorly understood. Here we demonstrate that NMDARs containing the developmentally regulated NR3A subunit undergo rapid endocytosis from the dendritic plasma membrane in cultured rat hippocampal neurons. This endocytic removal is regulated by PACSIN1/syndapin1, which directly and selectively binds the carboxy-terminal domain of NR3A through its NPF motifs and assembles a complex of proteins including dynamin and clathrin. Endocytosis of NR3A by PACSIN1 is activity dependent, and disruption of PACSIN1 function causes NR3A accumulation at synaptic sites. Our results reveal a new activity-dependent mechanism involved in the regulation of NMDAR expression at synapses during development, and identify a brain-specific endocytic adaptor that confers spatiotemporal and subunit specificity to NMDAR endocytosis.

Axodendritic contacts onto calcium/calmodulin-dependent protein kinase type II-expressing neurons in the barn owl auditory space map

In the owl midbrain, a map of auditory space is synthesized in the inferior colliculus (IC) and conveyed to the optic tectum (OT). Ascending auditory information courses through these structures via topographic axonal projections. Little is known about the molecular composition of projection neurons or their postsynaptic targets. To visualize axodendritic contacts between identified cell types, we used double-label immunohistochemistry, in vivo retrograde tracing, in vitro anterograde tracing, high-resolution confocal microscopy, three-dimensional reconstruction and fly-through visualization. We discovered a major class of IC neurons that strongly expressed calcium/calmodulin-dependent protein kinase type II, alpha subunit (CaMKII). The distribution of these cells within the IC was mostly restricted to the external nucleus of the IC (ICX), in which the auditory space map is assembled. A large proportion of ICX-OT projection neurons were CaMKII positive. In addition to being the principal outputs, CaMKII cells were in direct contact with axonal boutons emanating from the main source of input to ICX, the lateral shell of the central nucleus of the inferior colliculus (ICCls). Numerous sites of putative synaptic contact were found on the somata, proximal dendrites, and distal dendrites. Double-label immunoelectron microscopy confirmed the existence of synapses between ICCls axons and the dendrites of CaMKII cells. Collectively, our data indicate that CaMKII ICX neurons are a cellular locus for the computation of auditory space-specific responses. Because the ICCls-ICX projection is physically altered during experience-dependent plasticity, these results lay the groundwork for probing microanatomical rearrangements that may underlie plasticity and learning.

Stereotyped axon pruning via plexin signaling is associated with synaptic complex elimination in the hippocampus

Plexin signaling is required for stereotyped pruning of long axon collaterals in the vertebrate CNS; however, a cellular basis for plexins on stereotyped pruning has not been determined. Using quantitative electron microscopy and immunocytochemistry, we found that infrapyramidal mossy fiber axon collaterals form transient synaptic complexes with basal dendrites of CA3 pyramidal cells in the early postnatal mouse hippocampus. At later postnatal ages, these synaptic complexes stop maturing and are removed before stereotyped pruning by a mechanism that does not involve axon degeneration and glial cell engulfment. In knock-out mice that lack plexin-A3 signaling, the synaptic complexes continue to mature, and, as a result, the collaterals are not pruned. Thus, our results suggest that intact plexin-A3 signaling contributes to synaptic complex elimination, which is associated with stereotyped axon pruning.

Cycling of NMDA receptors during trafficking in neurons before synapse formation

The trafficking of glutamate receptors in neurons is of the utmost importance for synapse formation and synaptic plasticity. Recently, we demonstrated that both NMDA and AMPA receptors reside in mobile transport packets that are recruited rapidly and independently to nascent synapses. Here, we show that a large proportion of the glutamate receptor clusters in young cortical neurons are present on the surface of dendrites before synapses are formed and these surface-exposed transport packets are mobile. Exocytosis of glutamate receptors to the dendritic surface occurs via a SNARE [soluble n-ethylmaleimide-sensitive factor attachment protein (SNAP) receptor]-dependent SNAP-23-mediated mechanism. Endocytosis occurs rapidly after surface exposure; >50% of surface-labeled NMDA receptors (NMDARs) are endocytosed within 5 min. NMDARs are transported along microtubules on large tubulovesicular organelles, as indicated by immunoelectron microscopy, and are associated with EEA1 (early endosomal antigen 1) and SAP102 (synapse-associated protein 102), as indicated by immunocytochemistry. Most surprisingly, a large proportion of these transport packets cycle through the dendritic plasma membrane before synapse formation. These results suggest a novel model in which NMDARs cycle with the plasma membrane during pauses of movement along microtubules while trafficking.

Switching of NMDA receptor 2A and 2B subunits at thalamic and cortical synapses during early postnatal development

Switching of the NMDA receptor 2A (NR2A) and NR2B subunits at NMDA receptors is thought to underlie the functional changes that occur in NMDA receptor properties during the developmental epoch when neural plasticity is most pronounced. The cellular expression of NR2A and NR2B and the NR2 synaptic binding protein postsynaptic density-95 (PSD-95) was examined in the mouse somatosensory cortex and thalamus from postnatal day 2 (P2) to P15 using reverse transcription-PCR, in situ hybridization histochemistry, and immunocytochemistry. The localization of NR2A and NR2B subunits and PSD-95 was then studied at synapses in layer IV of somatosensory cortex and in the ventral posterior nucleus of the thalamus using high-resolution immunoelectron microscopy. At both cortical and thalamic synapses, a quantitative switch in the dominant synaptic subunit from NR2B to NR2A was accompanied by a similar change in the cellular expression of NR2A but not of NR2B. Synaptic PSD-95 developed independently, although both NR2A and NR2B colocalized with PSD-95. Displacement of NR2B subunits from synapses was not accompanied by an increase in an extrasynaptic pool of this subunit. Thus, the switch in synaptic NR2 subunit predominance does not occur by changes in expression or displacement from synapses and may reflect the formation of new synapses from which NR2B is lacking.

Hepatic fibrosis and long-term alcoholism: An analysis of 50 residents in Lhasa

AIM: To study the relationship between hepatic fibrosis and long-term alcoholism of residents in Lhasa area.

METHODS: Fifty individuals with more than 5-year alcoholic history in Lhasa area were involved in the study and 20 without alcoholic history were as control. Associated examinations consisting of liver functions, serum HbsAg, extracellular matrix (ECM) components (type IV collagen and hyaluronic acid, HA) and type B ultrasonic for hepatocholecystic system and spleen were used to assess the liver status.

RESULTS: Fifty individuals in the study group represented symptoms such as congestion of tongue edge, gingival atrophy, icteric sclera, telangiectasis. Ultrasonic examinations showed that the size of left hepatic lobe in the study group was significantly different from that in the control group (6.60±1.14 vs 5.89±0.91, P <0.01). The liver structure, portal vein diameter and liver blood vessels were also showing significant differences (56.0% vs 1.1%, P <0.05). The indexes of liver function such as GGT, AST (2 863±1 513 vs 1 119±644, 993±704 vs 518±271, P <0.01), ALT, TB, DbiL (1 132±970 vs 744±502, 20.5±10.7 vs 18.0±6.0, 5.8±5.6 vs 4.9±2.9, P <0.05) manifested significant differences between the study group and the control group. ECM IV and HA in the study group also showed prominent differences from those in the controls (155±109 vs 87±46, 210±141 vs 92±54, P <0.01).

CONCLUSION: Different degree of liver damage, hepatic structure changes and hepatic fibrosis appear in individuals with long-term alcoholism in Lhasa area. Hepatocellular damage is directly related to the volume of alcohol incepted and duration of alcoholic history. B-ultrasonography and serum biochemistry should be adopted for early diagnosis.

Fine structural localization of connexin-36 immunoreactivity in mouse cerebral cortex and thalamus

The mounting physiological evidence for low-resistance electrical coupling between thalamic and cortical neurons contrasts with a lack of morphological data on gap junctions in thalamus and cortex. Connexin-36 is a neuronally specific protein associated with low-resistance gap junctions in the central nervous system. Connexin-36 localization was studied in the mouse somatosensory cortex and thalamus by using immunocytochemistry and immunoelectron microscopy. Expression of connexin-36 immunoreactivity is widespread in the forebrain and significantly enhanced in the barrel cortex and thalamic reticular nucleus during the second postnatal week, but it extends to other thalamic nuclei as well. At the electron microscopic level, pre- and postembedding immunogold labeling revealed that 70-76% of connexin-36-immunolabeled particles were localized at focal sites on apposed plasma membranes of cortical and thalamic dendrites; approximately 5% of the particles were associated with parasynaptic membranes; but on no occasion could overt, morphologically identifiable gap junctions be demonstrated in association with connexin-36 immunoreactivity. The widespread distribution of focal concentrations of connexin-36 subunits could provide a basis for the electrical coupling that exists between cortical and reticular thalamic neurons, but morphologically definable gap junctions may be too small to be adequately visualized by conventional immunoelectron microscopy.

Temporal and regional expression of NMDA receptor subunit NR3A in the mammalian brain

NR3A is a developmentally regulated N-methyl-D-aspartate receptor (NMDAR) subunit that was previously known as NMDAR-L or chi-1. Unlike other NMDAR subunits, NR3A inhibits the NMDAR-associated ion channel in a novel manner, and a role in synaptogenesis has been suggested for this subunit. Here, we report a comprehensive study to delineate the temporal and anatomic expression of NR3A protein in the mammalian brain by using a monoclonal anti-NR3A antibody. NR3A protein was found to peak at postnatal day (P) 8, and to decrease gradually from P12 to adulthood in the rat central nervous system. Moreover, NR3A protein was heavily expressed in all areas of the isocortex, portions of the amygdaloid nuclei, and selective cell layers and nuclei of the hippocampus, thalamus, hypothalamus, brainstem, and spinal cord. NR3A protein was also expressed in the cerebellar cortex, whereas only weak signal was detected in the previous in situ studies by using riboprobes. At an ultrastructural level, NR3A was associated specifically with asymmetrical synapses and localized to postsynaptic membranes. This information will facilitate future research on NMDARs by providing clues to possible inclusion of the NR3A subunit in NMDARs in many brain regions.

Corticotropin-releasing factor is preferentially colocalized with excitatory rather than inhibitory amino acids in axon terminals in the peri-locus coeruleus region

Corticotropin-releasing factor(CRF)-immunoreactive terminals form synaptic specializations with locus coeruleus (LC) dendrites in rat brain. Within these terminals, CRF-immunoreactive dense core vesicles are colocalized with non-labeled dense core vesicles and clear vesicles, implicating other neuromodulators in the actions of CRF on LC neurons. Excitatory (glutamate) and inhibitory (GABA) amino acid afferents to the LC, have been identified which regulate noradrenergic responses to sensory stimuli. This study was designed to determine whether these amino acid neurotransmitters are colocalized with CRF in terminals within the LC/peri-LC region in the rat. Sections through the LC region that were dually labeled using immunohistochemical techniques to visualize either CRF and glutamate or CRF and GABA were examined using electron microscopy. Numerous terminals that contained immunolabeling for both CRF and glutamate (e.g. 30% of 106 CRF-immunoreactive terminals and 13% of 232 glutamate-immunolabeled terminals) were observed in the peri-LC. Additionally, single labeled CRF and glutamate terminals were often apposed to one another or found to converge on common dendritic targets. In contrast, relatively few terminals exhibited immunolabeling for both GABA and CRF (5% of 317 CRF-immunoreactive terminals). However, evidence for a postsynaptic effect of CRF on GABA-containing profiles included synapses between CRF axon terminals and GABA-labeled dendrites (10% of 317 CRF-labeled terminals), as well as appositions between CRF- and GABA-labeled terminals. These results indicate that CRF is preferentially colocalized with glutamate in the rostrolateral LC region and may impact on glutamate neurotransmission in the LC via presynaptic or postsynaptic actions. They argue against colocalization of CRF with GABA, although CRF may modulate GABA release via postsynaptic effects in the peri-LC region.

Effects of radiation on Ca2+signaling in salivary epithelial cell lines transfected with Bcl-2 and Bcl-XL

The effects of radiation on the Ca2+ signaling system in HSY cells transfected with the Bcl-2 or Bcl-XL gene were studied. Bcl-2 overexpression did not alter carbachol (CCh)-elicited initial increase in cytosolic free Ca2+ concentrations ([Ca2+]i), but Bcl-XL overexpression dramatically reduced this response. Exposure to 10 Gy gamma-ray did not alter basal [Ca2+]i. By contrast, the CCh-stimulated initial [Ca2+]i increase was reduced at 0.5 and 4 h post-irradiation in all cell types and remained decreased at 24 h in wild-type and control-transfected cells, but recovered in Bcl-2- and Bcl-XL-transfectants. The formation of inositol 1,4,5-trisphosphate (IP3) in response to CCh at 4-h post-irradiation was decreased in wild-type and control-transfected cells, but not in Bcl-2 and Bcl-XL transfectants. The capacity of the IP3-sensitive Ca2+ store was significantly reduced by radiation in all cells except Bcl-XL transfectants. Ca2+ influx after stimulation with CCh was suppressed by exposure to radiation in wild-type and control-transfected cells, but not in Bcl-2- and Bcl-XL-transfectants. However, radiation enhanced Ca2+ influx activated by thapsigargin in all cell types. These results suggest that 1) radiation diminishes IP3 formation and Ca2+ release in response to CCh, but potentiates the store-operated Ca2+ influx; and 2) overexpression of Bcl-2 or Bcl-XL partially protects cells from radiation-induced inhibition of Ca2+ signaling.

Differences in quantal amplitude reflect GluR4- subunit number at corticothalamic synapses on two populations of thalamic neurons

Low-frequency thalamocortical oscillations that underlie drowsiness and slow-wave sleep depend on rhythmic inhibition of relay cells by neurons in the reticular nucleus (RTN) under the influence of corticothalamic fibers that branch to innervate RTN neurons and relay neurons. To generate oscillations, input to RTN predictably should be stronger so disynaptic inhibition of relay cells overcomes direct corticothalamic excitation. Amplitudes of excitatory postsynaptic conductances (EPSCs) evoked in RTN neurons by minimal stimulation of corticothalamic fibers were 2.4 times larger than in relay neurons, and quantal size of RTN EPSCs was 2.6 times greater. GluR4-receptor subunits labeled at corticothalamic synapses on RTN neurons outnumbered those on relay cells by 3.7 times, providing a basis for differences in synaptic strength.

Characterization of the calcium signaling system in the submandibular cell line SMG-C6

Establishment of salivary cell lines retaining normal morphological and physiological characteristics is important in the investigation of salivary cell function. A submandibular gland cell line, SMG-C6, has recently been established. In the present study, we characterized the phosphoinositide (PI)-Ca2+ signaling system in this cell line. Inositol 1,4,5-trisphosphate(1,4,5-IP3) formation, as well as Ca2+ storage, release, and influx in response to muscarinic, alpha1-adrenergic, P2Y-nucleotide, and cytokine receptor agonists were determined. Ca2+ release from intracellular stores was strongly stimulated by acetylcholine (ACh) and ATP, but not by norepinephrine (NA), epidermal growth factor (EGF), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNFalpha). Consistently, 1, 4,5-IP3 formation was dramatically stimulated by ACh and ATP. ACh-stimulated cytosolic free Ca2+ concentration [Ca2+]i increase was inhibited by ryanodine, suggesting that the Ca2+-induced Ca2+ release mechanism is involved in the ACh-elicited Ca2+ release process. Furthermore, ACh and ATP partially discharged the IP3-sensitive Ca2+ store, and a subsequent exposure to thapsigargin (TG) induced further [Ca2+]i increase. However, exposure to TG depleted the store and a subsequent stimulation with ACh or ATP did not induce further [Ca2+]i increase, suggesting that ACh and ATP discharge the same storage site sensitive to TG. As in freshly isolated submandibular acinar cells, exposure to ionomycin and monensin following ACh or TG induced further [Ca2+]i increase, suggesting that IP3-insensitive stores exist in SMG-C6 cells. Ca2+ influx was activated by ACh, ATP, or TG, and was significantly inhibited by La3+, suggesting the involvement of store-operated Ca2+ entry (SOCE) pathway. These results indicate that in SMG-C6 cells: (i) Ca2+ release is triggered by muscarinic and P2Y-nucleotide receptor agonists through formation of IP3; (ii) both the IP3-sensitive and -insensitive Ca2+ stores are present; and (iii) Ca2+ influx is mediated by the store-operated Ca2+ entry pathway. We conclude that Ca2+ regulation in SMG-C6 cells is similar to that in freshly isolated SMG acinar cells; therefore, this cell line represents an excellent SMG cell model in terms of intracellular Ca2+ signaling.

Characterization of the calcium signaling system in the submandibular cell line SMG-C6

Establishment of salivary cell lines retaining normal morphological and physiological characteristics is important in the investigation of salivary cell function. A submandibular gland cell line, SMG-C6, has recently been established. In the present study, we characterized the phosphoinositide (PI)-Ca2+ signaling system in this cell line. Inositol 1,4,5-trisphosphate(1,4,5-IP3) formation, as well as Ca2+ storage, release, and influx in response to muscarinic, alpha1-adrenergic, P2Y-nucleotide, and cytokine receptor agonists were determined. Ca2+ release from intracellular stores was strongly stimulated by acetylcholine (ACh) and ATP, but not by norepinephrine (NA), epidermal growth factor (EGF), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNFalpha). Consistently, 1, 4,5-IP3 formation was dramatically stimulated by ACh and ATP. ACh-stimulated cytosolic free Ca2+ concentration [Ca2+]i increase was inhibited by ryanodine, suggesting that the Ca2+-induced Ca2+ release mechanism is involved in the ACh-elicited Ca2+ release process. Furthermore, ACh and ATP partially discharged the IP3-sensitive Ca2+ store, and a subsequent exposure to thapsigargin (TG) induced further [Ca2+]i increase. However, exposure to TG depleted the store and a subsequent stimulation with ACh or ATP did not induce further [Ca2+]i increase, suggesting that ACh and ATP discharge the same storage site sensitive to TG. As in freshly isolated submandibular acinar cells, exposure to ionomycin and monensin following ACh or TG induced further [Ca2+]i increase, suggesting that IP3-insensitive stores exist in SMG-C6 cells. Ca2+ influx was activated by ACh, ATP, or TG, and was significantly inhibited by La3+, suggesting the involvement of store-operated Ca2+ entry (SOCE) pathway. These results indicate that in SMG-C6 cells: (i) Ca2+ release is triggered by muscarinic and P2Y-nucleotide receptor agonists through formation of IP3; (ii) both the IP3-sensitive and -insensitive Ca2+ stores are present; and (iii) Ca2+ influx is mediated by the store-operated Ca2+ entry pathway. We conclude that Ca2+ regulation in SMG-C6 cells is similar to that in freshly isolated SMG acinar cells; therefore, this cell line represents an excellent SMG cell model in terms of intracellular Ca2+ signaling.

G-protein signaling abnormalities mediated by CD95 in salivary epithelial cells

Salivary epithelial cells from patients with primary Sjögren's syndrome (SS) undergo Fas-mediated apoptosis. Bcl-2 and Bcl-xL are apoptosis suppressing oncogenes. Very little is known about the role of these oncogene molecules in salivary epithelial cells. To investigate the possible prevention of salivary glandular destruction in SS by Bcl-2 and Bcl-xL, stable transfectants expressing these molecules were made from HSY cells, a human salivary epithelial cell line. HSY cells were transfected with an expression vector for human Bcl-2 or Bcl-xL. Stable transfectants were selected and apoptosis was induced by anti-Fas antibody. Apoptosis was quantified by propidium iodide staining followed by flow cytometry. Caspase activity was detected by immunohistochemical analysis and enzyme cleavage of DEVD-AMC, a fluorescent substrate. Response to carbachol, a muscarinic receptor agonist, and EGF was measured by Ca2+ mobilization and influx. Fas-mediated apoptosis was significantly inhibited in Bcl-2 and Bcl-xL transfectants compared to wild-type and control transfectants (empty vector). Surprisingly, caspase activity was not inhibited in Bcl-2 and Bcl-xL transfectants. Activation of the Fas pathway in the Bcl-2 and Bcl-xL transfectants by antibody also inhibited carbachol and EGF responsiveness (i.e., Ca2+ mobilization and/or influx) by 50-60%. This Fas-mediated inhibition of cell activation was partially or completely restored by specific peptide interference of caspase enzyme activity. The prevention of Fas-mediated apoptosis by the overexpression of Bcl-2 and Bcl-xL in salivary gland epithelial cells results in injured cells expressing caspase activity and unable to respond normally to receptor agonists. Such damaged cells may exist in SS patients and could explain the severe dryness out of proportion to the actual number of apoptotic cells seen on salivary gland biopsy.

Effects of low concentrations of paraoxon on Ca(2+) mobilization in a human parotid salivary cell-line HSY

The salivary gland is a target organ of organophosphate pesticides (OPs). Inhibition of acetylcholinesterase (AChE) by OPs leads to a decrease in acetylcholine (ACh) breakdown that results in overstimulation of muscarinic cholinergic receptors (mChR). However, OPs may also directly interact with downstream elements of the phosphoinositide (PI) signalling pathway coupled with mChR. The present study examined the effects of exposure to low concentrations of the OP paraoxon on inositol 1,4,5-trisphosphate (IP(3)) formation and Ca(2+) mobilization in response to ACh or ATP in the human parotid cell-line HSY. Exposure to 0.1 and 1 nM, but not 10 nM, paraoxon for 24 hr significantly elevated the basal cytosolic free Ca(2+) ([Ca(2+)](i)). This increase was abolished by atropine. Ca(2+) release from the IP(3)-sensitive store in response to ACh or ATP, a P2Y-nucleotide agonist, was significantly increased in cells pre-exposed to 0.1 nM paraoxon. However, IP(3) formation was inhibited by paraoxon but mChR expression was not altered. Although IP(3) receptor expression was not changed, Ca(2+) release elicited by IP(3) in streptolysin O toxin-permeabilized cells was significantly larger in cells pre-exposed to 0.1 nM paraoxon, suggesting that paraoxon increases the sensitivity of IP(3) receptors. Paraoxon exposure also induced a concentration-dependent reduction in the total capacity of intracellular Ca(2+) stores, whereas the capacity of the IP(3)-sensitive Ca(2+) store was not altered by paraoxon, as judged by discharging of the IP(3)-sensitive Ca(2+) store with thapsigargin (TG). Ca(2+) influx stimulated by ACh or ATP was also enhanced by 0.1 nM, but not 1 and 10 nM, paraoxon. On the other hand, Ca(2+) influx activated by TG was enhanced by exposure to all concentrations of paraoxon, indicating that paraoxon modulates the Ca(2+) entry pathway. These results suggest that low concentrations of paraoxon interact with elements of the PI pathway, enhancing Ca(2+) release and influx mechanisms.

Evidence for coexistence of enkephalin and glutamate in axon terminals and cellular sites for functional interactions of their receptors in the rat locus coeruleus

The authors previously showed that a subset of axon terminals in the locus coeruleus (LC) contains methionine5-enkephalin (ENK) and gamma-aminobutyric acid (GABA) immunoreactivities. However, numerous ENK-labeled terminals lacked GABA and exhibited synaptic specializations that were characteristic of excitatory-type transmitters. To determine whether ENK coexists with glutamate in the LC, preembedding immunoperoxidase detection of ENK or immunogold-silver was combined with postembedding identification of glutamate using a gold marker. Indeed, 28% of the ENK-labeled axon terminals examined (n = 250 axon terminals) also contained glutamate. To define further sites for functional interactions between opiate ligands and excitatory amino acid receptors, the ultrastructural localization of the mu-opioid receptor (MOR) was examined with respect to either the kainate receptor (KAR) or the R1 subunit of the N-methyl-D-aspartate (NR1)-type glutamate receptor in the LC. Gold-silver labeling for MOR and peroxidase labeling for either KAR or NR1 indicated that the MOR often was localized to the plasma membrane of dendrites that also exhibited immunolabeling for either glutamate receptor subtype. In contrast to the KAR, which was identified primarily in somata and dendrites, NR1 immunoreactivity also was found frequently in axon terminals as well as in glial processes. Glial processes containing NR1 occasionally exhibited immunolabeling for MOR and sometimes were directly apposed to MOR-containing dendrites in the LC. Furthermore, NR1-labeled receptors in axon terminals sometimes were presynaptic to MOR-labeled dendrites. The authors concluded that ENK and glutamate may be cotransmitters in LC afferents. Moreover, ligands at the KAR may modulate directly MOR-containing neurons in the LC, whereas actions at NR1 receptors may affect opioid-sensitive neurons through multiple cellular mechanisms, i.e., through presynaptic, postsynaptic, or glial actions.

Predominance of corticothalamic synaptic inputs to thalamic reticular nucleus neurons in the rat

Quantitative electron microscopy was used to examine the relative contributions of different types of synapses to the circuitry of the thalamic reticular nucleus (RTN) in the rat. Single RTN cells were injected with Lucifer Yellow (LY) in fixed brain slices and examined after photoconversion; corticothalamic axons and terminals were labeled by anterograde transport of Phaseolus vulgaris-leucoagglutinin (PHA-L); and gamma-aminobutyric acid (GABA)ergic terminals were labeled by postembedding immunocytochemistry. Three types of synapses, made by morphologically distinguishable small terminals (ST), large terminals (LT), and GABAergic terminals, were distributed on all portions of the dendritic trees of injected RTN cells. ST and LT terminals formed asymmetrical, presumed excitatory, synaptic contacts. On proximal dendrites, approximately 50% of the synapses were ST, 30-40% were LT, and 10-25% were GABAergic. On distal dendrites, 60-65% were ST, 20% were LT, and 15% were GABAergic. PHA-L labeling showed that labeled corticothalamic terminals and ST terminals have identical morphological features and the same distribution patterns on RTN dendrites, indicating that the majority of excitatory afferents to RTN neurons are derived from the cerebral cortex. The LT terminals found in smaller numbers are probably derived from collateral axons of thalamocortical relay cells. GABAergic terminals formed by LY-labeled, intra-RTN axon collaterals were relatively few in number, and no dendrodendritic synapses were observed.

Development of metabotropic glutamate receptors from trigeminal nuclei to barrel cortex in postnatal mouse

Expression patterns of group I (mGluR1alpha and mGluR5) and group II (mGluR2/3) metabotropic glutamate receptor subtypes were examined immunocytochemically in the trigeminal system of mice during the first 3 weeks of postnatal development, when somatotopic whisker representations are sequentially established from brainstem through thalamus to cerebral cortex. Immunostaining for all three epitopes formed whisker-related patterns in the trigeminal nuclei from postnatal day (P) 0, in the ventral posterior thalamic nucleus from P2, and in the posteromedial barrel subfield of somatosensory cortex (SI) from P4. The appearance of whisker-related patterns was preceded by increased levels of immunostaining of the neuropil, which subsequently declined from the trigeminal nuclei upward. In SI, mGluR1alpha-positive neurons were observed in all cortical layers from P2. mGluR5 was localized in neurons, glial cells, and neuropil from P2. mGluR2/3 immunostaining was distributed only in the neuropil at all ages. The three receptor subtypes showed moderate to high expression in deep layer V throughout development. Transient expression peaked in the hollows of layer IV barrels from P4 to P9, and then fell off as expression increased in supragranular layers from P14 to P21. The deep aspect of the cortical subplate (layer VIb) showed dense mGluR5 and less dense mGluR1alpha immunostaining throughout development. Up-regulation of expression of group I and II mGluRs is correlated with the growth and refinement of connectivity and the establishment of somatotopic patterns in the three main relay stations of the trigeminal system. This finding suggests roles for mGluRs in the early processing of sensory information and in developmental plasticity.

Changes in subcellular localization of metabotropic glutamate receptor subtypes during postnatal development of mouse thalamus

High resolution immunoelectron microscopy was used to study subcellular localization patterns of three metabotropic glutamate receptor subtypes (mGluR1alpha, mGluR5, and mGluR2/3) during postnatal development of mouse ventral posterior (VP) thalamic nucleus. Immunoreactivity for all three mGluRs was detected from birth (postnatal day 0, P0), but mGluR1alpha showed dramatic changes in localization with age. In the first postnatal week, mGluR1alpha immunoreactivity was mainly found in proximal dendrites and somata and not usually associated with synaptic contacts. From the second postnatal week, it became concentrated in distal dendrites and preferentially associated with corticothalamic (RS) synapses. mGluR5 immunoreactivity was weaker than mGluR1alpha immunoreactivity at all postnatal ages and showed a similar change in subcellular distribution to that of mGluR1alpha. It was also localized in astrocytic processes. mGluR2/3 immunoreactivity was mainly localized in astrocytic processes surrounding neuronal somata and synapses and this pattern was consistently maintained through all postnatal ages. A small number of presynaptic axon terminals were labeled for mGluR2/3 immunoreactivity and formed asymmetrical synapses. This study demonstrates that Group I mGluR proteins (mGluR1alpha and mGluR5) become redistributed in association with the development of corticothalamic function as demonstrated physiologically, whereas Group II mGluR proteins (mGluR2/3) are mainly associated with neuroglia.

Local excision of the parotid gland in the treatment of Warthin's tumour

The results of local excision of Warthin's tumour in the parotid gland (n = 61) (resection of the tumour together with surrounding normal gland and associated lymph nodes) were compared with those of superficial parotidectomy (n = 88) for incidence of recurrence, duration of operation, and degree of facial deformity. A subgroup of patients in each group were tested for gustatory sweating (iodine starch test) and parotid function (quantitative scintigraphy). Local excision had the following advantages over superficial parotidectomy: shorter operating time, less risk of facial nerve damage, less facial deformity, lower incidence of Frey's syndrome, and better preservation of the function of the parotid gland.

Smoking and the development of Warthin's tumour of the parotid gland

The smoking history was surveyed in 160 consecutive patients with Warthin's tumour of the parotid gland in order to investigate the relationship between smoking and the development of this tumour. Two hundred cases of middle-aged or elderly normal persons and 163 consecutive patients with pleomorphic adenoma in the parotid gland served as controls. The percentage of smoking in patients with Warthin's tumour (96.3%) was much higher than that of middle-aged or elderly normal persons (25.5%) and in patients with pleomorphic adenoma (26.4%). Moreover, the amount of smoking was greater and the smoking history was longer in patients with Warthin's tumour. When the male and female patients were analysed respectively, the same result was shown. This case-control study suggests that smoking may be one of the aetiologic factors associated with the development of Warthin's tumour.

Subcellular distribution of AMPA and NMDA receptor subunit immunoreactivity in ventral posterior and reticular nuclei of rat and cat thalamus

Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-D-aspartate (NMDA) selective glutamate receptors mediate excitatory neurotransmission in the somatosensory thalamus, but morphological localization of the receptors at identified thalamic synapses has been lacking. The authors used electron microscopic immunocytochemistry to localize AMPA selective GluR 2/3 subunits (GluR2/3) and NMDA receptor subunit 1 (NMDAR1) in rat and cat ventral posterior lateral nucleus (VPL) and in the associated sector of the reticular nucleus (RTN). Light microscopy showed that GluR2/3 and NMDAR1 immunolabeled neurons are homogeneously distributed in both nuclei. The relationship between glutamate receptor labeled profiles and glutamate or gamma-aminobutyric acid (GABA) labeled synapses was revealed by combining preembedding and postembedding immunostaining at the electron microscopic level. GluR2/3 and NMDAR1 immunoreactivity was located in somata and in proximal and distal dendrites of VPL relay cells and of RTN cells. Immunoreactivity was concentrated in postsynaptic densities of glutamatergic synapses and absent from postsynaptic densities of GABAergic synapses. In the cat, GluR2/3 and NMDAR1 immunoreactivity was also localized in GABAergic interneurons, including their presynaptic dendrites (PSD). Of the GluR2/3 and NMDAR1 labeled thalamic synapses observed, 10-29% were lemniscal (RL) type synapses in VPL; 60-70% were corticothalamic (RS) type synapses in the VPL and RTN. In the cat, 7-19% were identified as PSD profiles, and more NMDAR1 labeled PSD were found in the VPL than in the RTN. The main findings were as follows: 1) AMPA selective GluR2/3 and NMDAR1 share similar distribution patterns in the rat and cat somatosensory thalamus, 2) both glutamate receptors are likely to be colocalized at postsynaptic densities of both RL and RS synapses, and 3) localization of the glutamate receptor proteins in GABAergic dendrites in the cat thalamus indicates that glutamatergic transmission to GABAergic neurons is also mediated by both NMDA and non-NMDA receptors.

Localization of alpha type II calcium calmodulin-dependent protein kinase at glutamatergic but not gamma-aminobutyric acid (GABAergic) synapses in thalamus and cerebral cortex

The alpha subunit of type II calcium/calmodulin-dependent protein kinase (CAM II kinase-alpha) plays an important role in longterm synaptic plasticity. We applied preembedding immunocytochemistry (for CAM II kinase-alpha) and postembedding immunogold labeling [for glutamate or gamma-aminobutyric acid (GABA)] to explore the subcellular relationships between transmitter-defined axon terminals and the kinase at excitatory and inhibitory synapses in thalamus and cerebral cortex. Many (but not all) axon terminals ending in asymmetric synapses contained presynaptic CAM II kinase-alpha immunoreactivity; GABAergic terminals ending in symmetric synapses did not. Postsynaptically, CAM II kinase-alpha immunoreactivity was associated with postsynaptic densities of many (but not all) glutamatergic axon terminals ending on excitatory neurons. CAM II kinase-alpha immunoreactivity was absent at postsynaptic densities of all GABAergic synapses. The findings show that CAM II kinase-alpha is selectively expressed in subpopulations of excitatory neurons and, to our knowledge, demonstrate for the first time that it is only associated with glutamatergic terminals pre- and postsynaptically. CAM II kinase-alpha is unlikely to play a role in plasticity at GABAergic synapses.

Synaptic distribution of afferents from reticular nucleus in ventroposterior nucleus of cat thalamus

This study was aimed at determining the synaptic circuitry that contributes to the alterations in thalamic function that accompany changes in behavioral states. The somatosensory sector of the thalamic reticular nucleus (RTN) was identified by microelectrode recording in cats and injected with Phaseolus vulgaris-leucoagglutinin (PHA-L). The axons of labeled RTN cells gave rise to collaterals within the RTN and continued into the dorsal thalamus where they terminated predominately in the ventral posterior lateral nucleus (VPL). After small injections in the upper limb representation of RTN, most labeled terminations in VPL were confined to its medial part, suggesting the presence of a topographic organization in the projection. Terminations were concentrated in localized, focal aggregations of boutons. Combined electron microscopic immunocytochemistry, using immunogold labeling for gamma-aminobutyric acid (GABA), showed that the PHA-L labeled boutons were GABA-positive terminals that ended in symmetrical synapses. Eighty-two percent of these synapses were on dendrites of relay neurons, 8.5% on dendrites of interneurons, and 9.3% on somata. The terminals of RTN axons form the majority of axon terminals ending in symmetrical synapses in VPL. Their concentration on relay neurons probably underlies the capacity of the RTN projection to reduce background activity of VPL relay neurons in the awake state and to maintain oscillatory behavior of these neurons in drowsiness and early phases of sleep.

Distribution of four types of synapse on physiologically identified relay neurons in the ventral posterior thalamic nucleus of the cat

This study was aimed at providing quantitative data on the thalamic circuitry that underlies the central processing of somatosensory information. Four physiologically identified thalamocortical relay neurons in the ventral posterior lateral nucleus (VPL) of the cat thalamus were injected with horseradish peroxidase and subjected to quantitative electron microscopy after pre- or postembedding immunostaining for gamma-aminobutyric acid to reveal synaptic terminals of thalamic inhibitory neurons. The four cells all had rapidly adapting responses to light mechanical stimuli applied to their receptive fields, which were situated on hairy or glabrous skin or related to a joint. Their dendritic architecture was typical of cells previously described as type I relay cells in VPL, and they lacked dendritic appendages. Terminals ending in synapses on the injected cells were categorized as RL (ascending afferent), F (inhibitory), PSD (presynaptic dendrite), and RS (mainly corticothalamic) types and were quantified in reconstructions of serial thin sections. RL and F terminals formed the majority of the synapses on proximal dendrites (approximately 50% each). The number of synapses formed by RL terminals declined on intermediate dendrites, but those formed by F terminals remained relatively high, declining to moderate levels (20-30%) on distal dendrites. RS terminals formed moderate numbers of the synapses on intermediate dendrites and the majority (> 60%) of the synapses on distal dendrites. Synapses formed by PSDs were concentrated on intermediate dendrites and were few in number (approximately 6%). They formed synaptic triads with F terminals and rarely with RL terminals. On somata, only a few synapses were found, all made by F terminals. The total number of synapses per cell was calculated to be 5,584-8,797, with a density of 0.6-0.9 per micrometer of dendritic length. Of the total, RL terminals constituted approximately 15%, F terminals approximately 35%, PSD terminals approximately 5%, and RS terminals approximately 50%. These results provide the first quantitative assessment of the synaptic architecture of thalamic somatic sensory relay neurons and show the basic organizational pattern exhibited by representatives of the physiological type of relay neurons most commonly encountered in the VPL nucleus.

[Effect of promoting blood circulation to remove stasis and supplementing qi and nourishing yin on the lipid peroxide and superoxide dismutase during experimental pulmonary fibrosis]

The preventive and therapeutic effect of the traditional Chinese compound medicine Feixiankang (FXK) on the mice pulmonary fibrosis formation have been studied with the mice model. The level of LPO and the activity of SOD in the mice lung showed that LPO increased remarkably (P < 0.01), while the activity of SOD decreased significantly (P < 0.01) during the alveolar pneumonia period, although the LPO content had no significant change (P < 0.01) during experimental pulmonary fibrosis formation. In addition, the effect of FXK on the reducing of LPO was much stronger than that of the antioxidative agent Vitamin E. Also, FXK could improve the activity of SOD.

[Clinical study on the type of operation in the treatment of acute necrotizing pancreatitis]

The type of operation in the treatment of acute necrotizing pancreatitis (ANP) is still controversial. Seventy-two surgical cases of ANP by using three different approaches since 1985 were analyzed retrospectively. The total mortality rate was 25%. The sump drainage was used in 28 cases, marsupialization in 11 cases and retroperitoneal drainage in 33 cases. The mortality rates were 25%, 36.4% and 21% respectively. The selection of approaches should be determined by clinical pathological types and by whether or not there is a retroperitoneal invasion. Sump drainage is a simple approach for ANP and is preferable in cases of sporadic focal necrosis. For extensive fusional pancreatic necrosis not complicated with retroperitoneal invasion, marsupialization is used, and in those with the invasion retroperitoneal drainage is the procedure of choice.

A method for fixation of previously fresh-frozen human adult and fetal brains that preserves histological quality and immunoreactivity

A method is described that enables fixation of previously fresh-frozen and stored adult and fetal human or animal brains. The method involves fixing during thawing under controlled, cryoprotected conditions and is compatible with good histological quality and the preservation of enzymatic activity and immunoreactivity of many neural antigens. It offers considerable advantages for the storage of large amounts of tissue from which multiple samples can be taken and processed under fixation and other conditions that can be optimized for a variety of methods, many of which may be incompatible if the whole brain is fixed in a single fixative prior to storage.