Enhanced pre-synaptic glutamate release in deep-dorsal horn contributes to calcium channel alpha-2-delta-1 protein-mediated spinal sensitization and behavioral hypersensitivity

Nerve injury-induced expression of the spinal calcium channel alpha-2-delta-1 subunit (Ca_vα₂δ₁) has been shown to mediate behavioral hypersensitivity through a yet identified mechanism. We examined if this neuroplasticity modulates behavioral hypersensitivity by regulating spinal glutamatergic neurotransmission in injury-free transgenic mice overexpressing the Ca_vα₂δ₁ proteins in neuronal tissues. The transgenic mice exhibited hypersensitivity to mechanical stimulation (allodynia) similar to the spinal nerve ligation injury model. Intrathecally delivered antagonists for N-methyl-D-aspartate (NMDA) and α-amino-3-hydroxyl-5-methylisoxazole-4-propionic acid (AMPA)/kainate receptors, but not for the metabotropic glutamate receptors, caused a dose-dependent allodynia reversal in the transgenic mice without changing the behavioral sensitivity in wild-type mice. This suggests that elevated spinal Ca_vα₂δ₁ mediates allodynia through a pathway involving activation of selective glutamate receptors. To determine if this is mediated by enhanced spinal neuronal excitability or pre-synaptic glutamate release in deep-dorsal horn, we examined wide-dynamic-range (WDR) neuron excitability with extracellular recording and glutamate-mediated excitatory postsynaptic currents with whole-cell patch recording in deep-dorsal horn of the Ca_vα₂δ₁ transgenic mice. Our data indicated that overexpression of Ca_vα₂δ₁ in neuronal tissues led to increased frequency, but not amplitude, of miniature excitatory post synaptic currents mediated mainly by AMPA/kainate receptors at physiological membrane potentials, and also by NMDA receptors upon depolarization, without changing the excitability of WDR neurons to high intensity stimulation. Together, these findings support a mechanism of Ca_vα₂δ₁-mediated spinal sensitization in which elevated Ca_vα₂δ₁ causes increased pre-synaptic glutamate release that leads to reduced excitation thresholds of post-synaptic dorsal horn neurons to innocuous stimuli. This spinal sensitization mechanism may mediate at least partially the neuropathic pain states derived from increased pre-synaptic Ca_vα₂δ₁ expression.

CFTR regulation of intracellular pH and ceramides is required for lung endothelial cell apoptosis

The functional significance of the expression of cystic fibrosis transmembrane regulator (CFTR) on endothelial cells has not yet been elucidated. Since CFTR has been implicated in the regulation of intracellular sphingolipid levels, which are important regulators of endothelial cell apoptosis in response to various insults, we investigated the role of CFTR in the apoptotic responses of lung endothelial cells. CFTR was detected as a functional chloride channel in primary lung endothelial cells isolated from both pulmonary arteries (human or mouse) and bronchial arteries (sheep). Both specific CFTR inhibition with 2-(phenylamino) benzoic acid diphenylamine-2-carboxylic acid, 5-[(4-carboxyphenyl)methylene]-2-thioxo-3-[(3-trifluoromethyl)phenyl-4-thiazolidinone (CFTR(inh)-172), or 5-nitro-2-(3-phenylpropylamino)benzoic acid and CFTR knockdown significantly attenuated endothelial cell apoptosis induced by staurosporine or H(2)O(2). CFTR(inh)-172 treatment prevented the increases in the ceramide:sphingosine-1 phosphate ratio induced by H(2)O(2) in lung endothelial cells. Replenishing endogenous ceramides via sphingomyelinase supplementation restored the susceptibility of CFTR-inhibited lung endothelial cells to H(2)O(2)-induced apoptosis. Similarly, the anti-apoptotic phenotype of CFTR-inhibited cells was reversed by lowering the intracellular pH, and was reproduced by alkalinization before H(2)O(2) challenge. TUNEL staining and active caspase-3 immunohistochemistry indicated that cellular apoptosis was decreased in lung explants from patients with cystic fibrosis compared with those with smoking-induced chronic obstructive lung disease, especially in the alveolar tissue and vascular endothelium. In conclusion, CFTR function is required for stress-induced apoptosis in lung endothelial cells by maintaining adequate intracellular acidification and ceramide activation. These results may have implications in the pathogenesis of cystic fibrosis, where aberrant endothelial cell death may dysregulate lung vascular homeostasis, contributing to abnormal angiogenesis and chronic inflammation.

Dopamine D1-Like Receptors Depress Excitatory Synaptic Transmissions in Striatal Neurons After Transient Forebrain Ischemia

Background and Purpose— Spiny neurons in the neostriatum are highly vulnerable to ischemia. Despite an enormous body of research suggesting that dopamine is involved in ischemia-induced neuronal loss in the striatum, it remains unclear how dopamine interacts with the glutamatergic excitotoxicity that is widely accepted as a major cause of ischemic cell death. Our study was designed to investigate the effects of dopamine D1 receptor (D1R) activation on excitatory neurotransmission in postischemic striatal neurons.

Methods— We used the 4-vessel occlusion ischemia model and brain slice preparations. Whole-cell voltage-clamp recording was performed on striatal neurons to measure excitatory postsynaptic currents (EPSCs). Systemic administration of a D1R agonist after ischemia and hematoxylin/eosin staining were performed to evaluate the effects of D1R activation on ischemia-induced neuronal degeneration in the striatum.

Results— D1R activation depressed EPSCs in postischemic striatal neurons. The depression was attributable to inhibition of presynaptic release. An activator of cAMP-dependent protein kinase A (PKA) mimicked the depressive effects of D1R activation. Bath application of a PKA inhibitor blocked the depression of EPSCs, whereas intracellular postsynaptic application of the PKA inhibitor had no effect. The D1R agonist failed to reduce EPSC amplitude in the presence of an adenosine A1 receptor antagonist. Systemic administration of a D1R agonist after ischemia significantly attenuated ischemia-induced cell death in the striatum.

Conclusions— These results indicate that D1R activation presynaptically depresses excitatory synaptic transmission in striatal neurons after ischemia through activation of PKA and adenosine A1 receptors and thus demonstrate a novel mechanism of D1R-mediated protection against ischemia.

Regulation of Kv4.2 channels by glutamate in cultured hippocampal neurons

Somatodendritic voltage-dependent K(+) currents (Kv4.2) channels mediate transient A-type K(+) currents and play critical roles in controlling neuronal excitability. Accumulating evidence has indicated that Kv4.2 channels are key regulatory components of the signaling pathways that lead to synaptic plasticity. In contrast to the extensive studies of glutamate-induced AMPA [(+/-) alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid hydrate] receptors redistribution, less is known about the regulation of Kv4.2 by glutamate. In this study, we report that brief treatment with glutamate rapidly reduced total Kv4.2 levels in cultured hippocampal neurons. The glutamate effect was mimicked by NMDA, but not by AMPA. The effect of glutamate on Kv4.2 was dramatically attenuated by pre-treatment of NMDA receptors antagonist MK-801 [(5S,10R)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine hydrogen maleate] or removal of extracellular Ca(2+). Immunocytochemical analysis showed a loss of Kv4.2 clusters on the neuronal soma and dendrites following glutamate treatment, which was also dependent on the activation of NMDA receptors and the influx of Ca(2+). Furthermore, whole-cell patch-clamp recordings revealed that glutamate caused a hyperpolarized shift in the inactivation curve of A-type K(+) currents, while the activation curve remained unchanged. These results demonstrate a glutamate-induced alteration of Kv4.2 channels in cultured hippocampal neurons, which might be involved in activity-dependent changes of neuronal excitability and synaptic plasticity.

Efficient non-unique probes selection algorithms for DNA microarray

Background

Temperature and salt concentration are very helpful experimental conditions for a probe to hybridize uniquely to its intended target. In large families of closely related target sequences, the high degree of similarity makes it impossible to find a unique probe for every target. We studied how to select a minimum set of non-unique probes to identify the presence of at most d targets in a sample where each non-unique probe can hybridize to a set of targets.

Results

We proposed efficient algorithms based on Integer Linear Programming to select a minimum number of non-unique probes using d-disjunct matrices. Our non-unique probes selection can also identify up to d targets in a sample with at most k experimental errors. The decoding complexity of our algorithms is as simple as O(n). The experimental results show that the decoding time is much faster than that of the methods using d-separable matrices while running time and solution size are comparable.

Conclusions

Since finding unique probes is often not easy, we make use of non-unique probes. Minimizing the number of non-unique probes will result in a smaller DNA microarry design which leads to a smaller chip and considerable reduction of cost. While minimizing the probe set, the decoding ability should not be diminished. Our non-unique probes selection algorithms can identify up to d targets with error tolerance and the decoding complexity is O(n).

Transient cerebral ischemia increases CA1 pyramidal neuron excitability

In human and experimental animals, the hippocampal CA1 region is one of the most vulnerable areas of the brain to ischemia. Pyramidal neurons in this region die 2-3 days after transient cerebral ischemia whereas other neurons in the same region remain intact. The mechanisms underlying the selective and delayed neuronal death are unclear. We tested the hypothesis that there is an increase in post-synaptic intrinsic excitability of CA1 pyramidal neurons after ischemia that exacerbates glutamatergic excitotoxicity. We performed whole-cell patch-clamp recordings in brain slices obtained 24 h after in vivo transient cerebral ischemia. We found that the input resistance and membrane time constant of the CA1 pyramidal neurons were significantly increased after ischemia, indicating an increase in neuronal excitability. This increase was associated with a decrease in voltage sag, suggesting a reduction of the hyperpolarization-activated non-selective cationic current (I(h)). Moreover, after blocking I(h) with ZD7288, the input resistance of the control neurons increased to that of the post-ischemia neurons, suggesting that a decrease in I(h) contributes to increased excitability after ischemia. Finally, when lamotrigine, an enhancer of dendritic I(h), was applied immediately after ischemia, there was a significant attenuation of CA1 cell loss. These data suggest that an increase in CA1 pyramidal neuron excitability after ischemia may exacerbate cell loss. Moreover, this dendritic channelopathy may be amenable to treatment.

Inhibition of Ih in striatal cholinergic interneurons early after transient forebrain ischemia

Striatal cholinergic interneurons are relatively resistant to ischemic insults. These neurons express hyperpolarization-activated cation current (I(h)) that profoundly regulates neuronal excitability. Changes in neuronal excitability early after ischemia may be crucial for determining neuronal injury. Here we report that I(h) in cholinergic interneurons was decreased 3 h after transient forebrain ischemia, which was accompanied by a negative shift of the voltage dependence of activation. The inhibition of I(h) might be due to the tonic activation of adenosine A1 receptors, as blockade of A1 receptors significantly increased I(h) in postischemic neurons, but had no effect on control neurons. Consistent with the inhibition of I(h), postischemic neurons showed a reduction in both spontaneous firing and hyperpolarization-induced rebound depolarization. These findings indicate that I(h) may play excitatory roles in striatal cholinergic interneurons. Postischemic inhibition of I(h) might be a novel mechanism by which adenosine confers neuronal resistance to cerebral ischemia.

A new linearly-combined bi-exponential model for kinetic analysis of the isometric relaxation process of Bufo gastrocnemius under electric stimulation in vitro

There was a slow-relaxing tail of skeletal muscles in vitro upon the inhibition of Ca(2+)-pump by cyclopiazonic acid (CPA). Herein, a new linearly-combined bi-exponential model to resolve this slow-relaxing tail from the fast-relaxing phase was investigated for kinetic analysis of the isometric relaxation process of Bufo gastrocnemius in vitro, in comparison to the single exponential model and the classical bi-exponential model. During repetitive stimulations at a 2-s interval by square pulses of a 2-ms duration at 12 V direct currency (DC), the isometric tension of Bufo gastrocnemius was recorded at 100 Hz. The relaxation curve with tensions falling from 90% of the peak to the 15th datum before next stimulation was analyzed by three exponential models using a program in MATLAB 6.5. Both the goodness of fit and the distribution of the residuals for the best fitting supported the comparable validity of this new bi-exponential model for kinetic analysis of the relaxation process of the control muscles. After CPA treatment, however, this new bi-exponential model showed an obvious statistical superiority for kinetic analysis of the muscle relaxation process, and it gave the estimated rest tension consistent to that by experimentation, whereas both the classical bi-exponential model and the single exponential model gave biased rest tensions. Moreover, after the treatment of muscles by CPA, both the single exponential model and the classical bi-exponential model yielded lowered relaxation rates, nevertheless, this new bi-exponential model had relaxation rates of negligible changes except much higher rest tensions. These results suggest that this novel linearly-combined bi-exponential model is desirable for kinetic analysis of the relaxation process of muscles with altered Ca(2+)-pumping activity.

Decoding algorithms in pooling designs with inhibitors and error-tolerance

Pooling designs are used in DNA library screening to efficiently distinguish positive from negative clones, which is fundamental for studying gene functions and many other biological applications. One challenge is to design decoding algorithms for determining whether a clone is positive based on the test outcomes and a binary matrix representing the pools. This is more difficult in practice due to errors in biological experiments. More challenging still is a third category of clones called 'inhibitors' whose effect is to neutralise positives. We present a novel decoding algorithm identifying all positive clones in the presence of inhibitors and experimental errors.

The genetic basic and fine-mapping of a stable quantitative-trait loci for aluminium tolerance in rice

Aluminium (Al) toxicity is a primary cause of low rice productivity in acid soils. We have mapped a number of quantitative-trait loci (QTL) controlling Al tolerance in a recombinant inbred line population derived from a cross between the tolerant japonica cultivar Asominori and the sensitive indica cultivar IR24. Tolerance was assessed on the basis of relative root elongation. QTL were detected on chromosomes 1, 9, and 11, with the percentages of phenotypic variance explained ranging from 13.5 to 17.7%. Alleles from Asominori at all three QTL were associated with increased Al tolerance. qRRE-9 is expressed both in the genetic background of IR24 and in an Asominori/IR24-mixed background. qRRE-9 was reduced to the single recessive Mendelian factor Alt-9. High-resolution genetic and physical maps were constructed for Alt-9 in a BC(3)F(2) population of 1,043 individuals. Alt-9 maps between RM24702 and ID47-2 on chromosome 9, and co-segregates with RM5765.

Involvement of I(h) in dopamine modulation of tonic firing in striatal cholinergic interneurons

Striatal cholinergic interneurons are tonically active neurons and respond to sensory stimuli by transiently suppressing firing that is associated with sensorimotor learning. The pause in tonic firing is dependent on dopaminergic activity; however, its cellular mechanisms remain unclear. Here, we report evidence that dopaminergic inhibition of hyperpolarization-activated cation current (I(h)) is involved in this process. In neurons exhibiting regular firing in vitro, exogenous application of dopamine caused a prolongation of the depolarization-induced pause and an increase in the duration of slow afterhyperpolarization (sAHP) after depolarization. Partially blocking I(h) with specific blocker ZD7288 (4-ethylphenylamino-1,2-dimethyl-6-methylaminopyrimidinium chloride) reduced firing and mimicked the effects of dopamine on sAHP. The I(h), being active at membrane potentials negative than -50 mV, was inhibited by dopamine via activation of the D2-like receptor, but not D1-like receptor. The inhibitory effects of the D2 receptor activation on I(h) were mediated through a protein kinase A-independent cyclic AMP pathway. Consistently, D2-like receptor agonist quinpirole showed comparable effects on sAHP and firing rate as those induced by I(h) channel blocker. Moreover, dopamine was unable to further affect the sAHP duration in neurons when I(h) was blocked. These findings indicate that D2 receptor-dependent inhibition of I(h) may be a novel mechanism for modulating the pause response in tonic firing in cholinergic interneurons.

Chronic alcohol drinking alters neuronal dendritic spines in the brain reward center nucleus accumbens

Alcohol is known to affect glutamate transmission. However, how chronic alcohol affects the synaptic structure mediating glutamate transmission is unknown. Repeated alcohol exposure in a subject with familial alcoholic history often leads to alcohol addiction. The current study adopts alcohol-preferring rats, which are known to develop high drinking. Two-photon microscopy analysis indicates that chronic alcohol of 14 weeks either, under continuous alcohol (C-Alc) or with repeated deprivation (RD-Alc), causes dysmorphology--thickened, beaded, and disoriented dendrites that are reminiscent of reactive astrocytes--in a subpopulation of medium spiny neurons. The density of dendritic spines was found differentially lower in the nucleus accumbens of RD-Alc and C-Alc groups as compared with those of Water groups. Large-sized spines and multiple-headed spines were increased in the RD-Alc group. The NMDA receptor subunit NR1 proteins, as analyzed with Western blot, were upregulated in C-Alc, but not in RD-Alc. The upregulated NMDA receptor subunits of NR1 however, are predominantly a splice variant isoform with truncated exon 21, which is required for membrane-bound trafficking or anchoring into a spine synaptic site. These maladaptations may contribute to the transformation of spines. The changes, in density and head-size of spines and the corresponding NMDA receptors, demonstrated an alteration of microcircuitry for glutamate reception. The current study demonstrates for the first time that chronic alcohol exposure causes structural alteration of dendrites and their spines in the key reward brain region in animals that have a genetic background leading to alcohol addiction.

Heat shock fusion protein induces both specific and nonspecific anti-tumor immunity

Mucin 1 (MUC1) is a tumor antigen, and the most important epitopes that can induce cytotoxic T lymphocytes (CTL) reside in the variable-number tandem repeats (VNTR). Heat shock protein (HSP) complexes isolated from tumors have been shown to induce specific anti-tumor immunity. HSP alone can also induce nonspecific immunity. To explore the possibility to utilize the specific anti-tumor immunity induced by MUC1 VNTR and the nonspecific immunity induced by HSP, we constructed a recombinant protein (HSP65-MUC1) by fusing Bacillus Calmette-Guérin-derived HSP65 with the MUC1 VNTR peptide and tested its ability to induce anti-tumor activities in a tumor challenge model. The growth of MUC1-expressing tumors was significantly inhibited in mice immunized with HSP65-MUC1, both before and after tumor challenge. A much larger percentage of immunized mice survived the tumor challenge than non-immunized mice. Correlating with the anti-tumor activity, HSP65-MUC1 was shown to induce MUC1-specific CTL as well as nonspecific anti-tumor immunity. In the human system, HSP65-MUC1-loaded human DC induced the generation of autologous MUC1-specific CTL in vitro. These results suggest that exogenously applied HSP65-MUC1 may be used to treat MUC1 tumors by inducing the epitope-specific CTL as well as nonspecific anti-tumor responses mediated by the HSP part of the fusion protein.

Enhancement of Excitatory Synaptic Transmission in Spiny Neurons After Transient Forebrain Ischemia

Spiny neurons in the neostriatum are highly vulnerable to ischemia. Enhancement of excitatory synaptic transmissions has been implicated in ischemia-induced excitotoxic neuronal death. Here we report that evoked excitatory postsynaptic currents in spiny neurons were potentiated after transient forebrain ischemia. The ischemia-induced potentiation in synaptic efficacy was associated with an enhancement of presynaptic release as demonstrated by an increase in the frequency of miniature excitatory postsynaptic currents (mEPSCs) and a decrease in the paired-pulse ratio. The amplitude of inward currents evoked by exogenous application of glutamate did not show significant changes after ischemia, suggesting that postsynaptic mechanism is not involved. The ischemia-induced increase in mEPSCs frequency was not affected by blockade of voltage-gated calcium channels, but it was eliminated in the absence of extracellular calcium. Bath application of ATP P2X receptor antagonist pyridoxal-phosphate-6-azophenyl-2′,4′-disulfonic acid (PPADS) significantly reduced mEPSC frequency in ischemic neurons but had no effects on the control ones. Furthermore, the inhibitory effect of PPADS on ischemic neurons was abolished in Ca2+-free external solution. These results indicate that excitatory synaptic transmissions in spiny neurons are potentiated after ischemia via presynaptic mechanisms. Activation of P2X receptors and the consequent Ca2+ influx might contribute to the ischemia-induced facilitation of glutamate release.

[Comparison of algal removal efficiencies in different ecological treatment systems and their combinations]

The algal removal efficiencies and their trends of 8 experimental ecological treatment systems, which belonged to 5 groups, were studied under different hydraulic loading rates (HLR). The algal removal efficiencies were compared according to the seasonal changes under the optimum HLR. Gravel-bed horizontal-flow wetland, down-flow wetland, up-flow wetland, aerobic ponds or facultative ponds combined these systems. The results show that the best HLR is 0.8m3/(m2 x d) in all the experimental systems. The systems including aerobic pond and down-flow wetland show a stronger resistance to hydraulic shock loading, as well as horizontal-flow wetland. The algal removal rates of all the systems peaked to over 94% in summer and bottomed in winter that varied from 34% to 90%. It was the combined form that determined the removal efficiency of the ecological treatment systems. The combination system of down-flow and up-flow wetland present the highest capacity of algal removal efficiency and lower seasonal fluctuation, while the gravel-bed horizontal-flow wetland system present the lowest efficiency and higher seasonal fluctuation.

Atorvastatin Reduces the Expression of COX-2 mRNA in Peripheral Blood Monocytes from Patients with Acute Myocardial Infarction and Modulates the Early Inflammatory Response

Background: We examined the effect of atorvastatin on the expression of COX-2 in peripheral blood monocytes from patients with early stage of acute myocardial infarction (AMI), and the plasma C-reactive protein (CRP) concentrations were also examined.

Methods: Patients with AMI (n = 40) and with stable coronary heart disease (CHD; n = 18) were registered, and patients with AMI were randomly separated to a group that received routine therapy (group A, n = 20) or to a group that received routine therapy plus atorvastatin at 20 mg/day (group B, n = 20) for a week. Peripheral blood monocytes from patients with AMI both before and after treatment and from patients with stable CHD were isolated and cultured for 24 h. COX-2 mRNA expression was analyzed by reverse transcription-PCR. We measured concentrations of CRP in plasma by ELISA.

Results: COX-2 expression was activated in peripheral blood monocytes from patients with AMI [0.92 (0.13)] compared with patients with stable CHD [0.19 (0.08)]; after a week of treatment, COX-2 expression in group B (reduced by 66%) was obviously lower than in group A (reduced by 24%; P <0.05). Plasma concentrations of CRP from patients with AMI [43.3 (14.9) mg/L] were increased compared with those from patients with stable CHD [1.65 (0.78) mg/L; P <0.05]; after a week of treatment, CRP concentrations in group B (reduced by 62%) were lower than in group A (reduced by 35%; P <0.05). COX-2 expression in peripheral blood monocytes from patients with AMI was positively correlated with plasma CRP concentration (r = 0.662; P <0.05).

Conclusions: COX-2 may promote acute inflammatory process after AMI. Atorvastatin may improve the antiinflammatory effects through the COX-2 pathway.

Anti-SARS-CoV immunity induced by a novel CpG oligodeoxynucleotide

To develop CpG oligodeoxynucleotides (CpG ODNs) based therapy for prevention and treatment of severe acute respiratory syndrome (SARS), we selected a novel CpG ODN (BW001), which displays B-type CpG ODN structure feature at the 5′ and A-type CpG ODN structure feature at the 3′, and tested for its anti-SARS-CoV activity. We found that the supernatants of human PBMCs stimulated by BW001 significantly protected Vero cells from SARS-CoV infection. BW001 could stimulate human PBMCs and pDCs to secrete high level of IFN-α and promote human PBMCs and B cells to proliferate. Furthermore, we demonstrated that BW001 could activate CD19⁺ B cells and CD56⁺ NK cells in human PBMCs. In addition, BW001 could enhance NK cytotoxicity and IFN-γ secretion in human PBMCs. Together, BW001 represents a novel type of CpG ODN and may have potential for the development of treatment and prevention for SARS as well as other viral associated diseases.

[Atorvastatin reduces the expression of COX-2 mRNA in peripheral blood monocytes in patients with acute myocardial infarction and modulates the early inflammatory response]

OBJECTIVE

To measure the effect of atorvastatin on COX-2 expression in monocytes in patients with acute myocardial infarction (AMI).

METHODS

Forty patients with AMI (AMI group) and 18 patients with stable coronary heart disease (control group) were enrolled, and patients with AMI were randomly given routine therapy (n = 20) and routine therapy plus atorvastatin (20 mg/day, n = 20) for a week. Peripheral blood monocytes for each participant including patients with AMI were isolated and cultured for 24 hours. During the culture, monocytes in patients with pretreatment AMI were incubated with celecoxib in different concentration (0, 0.1, 1 and 10 micromol/L). COX-2 mRNA expression in monocytes was measured by reverse transcription polymerase chain reaction (RT-PCR); concentrations of interleukin-6 (IL-6) in supernatant from monocytes and plasma hs-CRP levels were measured by using enzyme-linked immunosorbent assay (ELISA).

RESULTS

COX-2 expression in monocytes in patients with AMI (0.92 +/- 0.13) was significantly higher than that in the control subjects (0.19 +/- 0.08), and decreased by 66% after atorvastatin (compared with that on routine therapy, P < 0.05); IL-6 secretions of monocytes in the AMI group (204.8 +/- 45.6 ng/L) increased dramatically compared with those in the control group (40.9 +/- 1.2 ng/L, P < 0.05), and reduced dramatically by 58% when incubated with 10 micromol/L celecoxib (P < 0.05) in a concentration-dependent manner; plasma levels of CRP in the AMI group (43.3 +/- 14.9 mg/L) significantly increased compared with those in the control group (1.7 +/- 0.8 mg/L), and reduced by 62% after atorvastatin (compared with those in the routine therapy group, P < 0.05). COX-2 expression in monocytes in the AMI group was positively correlated with both secretions of IL-6 and plasma level of CRP (r = 0.636 and 0.662, respectively, both P < 0.05).

CONCLUSIONS

There is an inflammatory activation in peripheral blood monocytes in patients with early AMI, and the monocytes-derived COX-2 may play an important role in promoting early inflammatory process. Atorvastatin may decrease COX-2 expression in peripheral blood monocytes in patients with AMI and cyclooxygenase-dependent pathway might be correlated with the anti-inflammation mechanism of statin.

Expression of TGF-β2 mRNA and PCNA, FN protein in lens epithelial cells in age-related nuclear and cortex cataract

By using RT-PCR and immunohistochemistry, the expressions of transforming growth factor beta2 (TGF-beta2) mRNA, proliferating cell nuclear antigen (PCNA) and fibronection (FN) protein in lens epithelial cells (LECs) of age-related nuclear and cortex cataract were detected and compared. The results of RT-PCR revealed that the expression of TGF-beta2 mRNA was higher in cortex cataract than in nuclear cataract. Immunohistochemistry demonstrated that the expression of PCNA protein was lower and the expression of FN protein was higher in cortex cataract than in nuclear cataract. It was suggested that TGF-beta2, PCNA and FN might take important parts in the process of age-related cataract. Cortex cataract was related to the transdifferentiation of LECs, and nuclear cataract to the proliferation of LECs.

[Significance and expression of cyclooxygenase-2 mRNA in peripheral blood monocytes in patients with acute coronary syndrome]

OBJECTIVE

To determine the expression of cyclooxygenase-2 (COX-2) mRNA in peripheral blood monocytes in patients with acute coronary syndrome (ACS), and to explore the effect of the expression of COX-2 mRNA in ACS.

METHODS

The expressions of COX-2 mRNA in peripheral blood monocytes from 18 normal subjects and 42 ACS patients were analyzed by reverse transcription polymerase chain reaction (RT-PCR), and the monocytes from patients were incubated with celecoxib in vitro. The concentrations of interleukin-6 (IL-6) and matrix metalloproteinase-9 (MMP-9) in supernates of monocytes were measured by enzyme-linked immunosorbent assays (ELISA).

RESULTS

The expression of COX-2 mRNA and the secrections of IL-6 and MMP-9 in peripheral blood monocytes in ACS patients significantly increased compared with those from normal controls [0.61 +/- 0.17 vs 0.11 +/- 0.09; (97.24 +/- 11.21) ng/L vs (22.15 +/- 6.30) ng/L; (41.20 +/- 8.41) g/L vs (11.76 +/- 4.23) g/L; all P < 0.05, respectively]. Celecoxib reduced IL-6 and MMP-9 secretion level of monocytes from ACS patients up to 48% and 50% respectively (all P < 0.05), in a concentration-dependent manner.

CONCLUSION

COX-2 in peripheral blood monocytes may play an important role in the acute coronary syndrome.

Effect of Atorvastatin on Tumor Necrosis Factor α Serum Concentration and mRNA Expression of Adipose in Hypercholesterolemic Rabbits

Tumor necrosis factor alpha (TNFalpha) is an inflammatory cytokine involved in atherogenesis. Adipose tissue is an important source of endogenous TNFalpha production. The aim of this study was to evaluate the effect of atorvastatin on TNFalpha serum concentration and mRNA expressions of subcutaneous adipose in hypercholesterolemic rabbits. Sixteen rabbits fed with a high-cholesterol diet for 8 weeks were randomly divided into 2 groups: (1) the high-cholesterol group (n=8) was maintained on a high-cholesterol diet for 6 weeks; (2) the atorvastatin group (n=8) had the same high-cholesterol diet plus atorvastatin (2.5 mg/kg/d) for 6 weeks. A control group (n=5) was fed with a normal diet for 14 weeks. Subcutaneous adipose was collected for mRNA analysis. Additionally, the direct effect of atorvastatin on TNFalpha release and mRNA expression was assayed in primary rabbit adipocytes. TNFalpha levels in serum and adipocyte culture supernatant were measured by ELISA. RT-PCR was used to evaluate TNFalpha mRNA expression in adipose and adipocytes. Serum TNFalpha concentration was significantly associated with serum total cholesterol (TC) and low-density lipoprotein-cholesterol (LDL-C) (both P<0.01). Compared with the control group, rabbits fed with a high-cholesterol diet showed higher levels of TNFalpha serum concentration and mRNA expression of adipose, both of which were significantly reduced by atorvastatin treatment (both P<0.05). TNFalpha mRNA expressions of adipose were significantly correlated with circulating TNFalpha levels among the 3 groups (r=0.51, P<0.05). Atorvastatin dose-dependently inhibited lipopolysaccharide (LPS)-induced TNFalpha secretion and mRNA expression in cultured adipocytes. In conclusion, atorvastatin can directly inhibit TNFalpha expression and secretion in adipocytes. Atorvastatin reduced TNFalpha serum concentration in hypercholesterolemic rabbits, which might be because of its cholesterol-lowering effect and direct inhibition of TNFalpha expression in adipose.

Alterations of potassium currents in ischemia-vulnerable and ischemia-resistant neurons in the hippocampus after ischemia

CA1 pyramidal neurons in the hippocampus die 2-3 days following transient forebrain ischemia, whereas CA3 pyramidal neurons and granule cells in the dentate gyrus remain viable. Excitotoxicity is the major cause of ischemic cell death, and potassium currents play important roles in regulating the neuronal excitability. The present study compared the changes of potassium currents in acutely dissociated hippocampal neurons at different intervals after ischemia. In CA1 neurons, the amplitude of rapid inactivating potassium currents (I(A)) was significantly increased at 14 h and returned to control levels at 38 h after ischemia; the rising slope and decay time constant of I(A) were accordingly increased after ischemia. The activation curve of I(A) in CA1 neurons shifted to the depolarizing direction at 38 h after ischemia. In granule cells, the amplitude and rising slope of I(A) were significantly increased at 38 h after ischemia; the inactivation curves of I(A) shifted toward the depolarizing direction accordingly at 38 h after ischemia. The I(A) remained unchanged in CA3 neurons after ischemia. The amplitudes of delayed rectifier potassium currents (I(Kd)) in CA1 neurons were progressively increased after ischemia. No significant difference in I(Kd) was detected in CA3 and granule cells at any time points after reperfusion. These results indicated that the voltage dependent potassium currents in hippocampal neurons were differentially altered after cerebral ischemia. The up-regulation of I(A) in dentate granule cells might have protective effects. The increase of I(Kd) in CA1 neurons might be associated with the neuronal damage after ischemia.

Increase of delayed rectifier potassium currents in large aspiny neurons in the neostriatum following transient forebrain ischemia

Large aspiny (LA) neurons in the neostriatum are resistant to cerebral ischemia whereas spiny neurons are highly vulnerable to the same insult. Excitotoxicity has been implicated as the major cause of neuronal damage after ischemia. Voltage-dependent potassium currents play important roles in controlling neuronal excitability and therefore influence the ischemic outcome. To reveal the ionic mechanisms underlying the ischemia-resistance, the delayed rectifier potassium currents (Ik) in LA neurons were studied before and at different intervals after transient forebrain ischemia using brain slices and acute dissociation preparations. The current density of Ik increased significantly 24 h after ischemia and returned to control levels 72 h following reperfusion. Among currents contributing to Ik, the margatoxin-sensitive currents increased 24 h after ischemia while the KCNQ/M current remained unchanged after ischemia. Activation of protein kinase A (PKA) down-regulated Ik in both control and ischemic LA neurons, whereas inhibition of PKA only up-regulated Ik and margatoxin-sensitive currents 72 h after ischemia, indicating an active PKA regulation on Ik at this time. Protein tyrosine kinases had a tonic inhibition on Ik to a similar extent before and after ischemia. Compared with that of control neurons, the spike width was significantly shortened 24 h after ischemia due to facilitated repolarization, which could be reversed by blocking margatoxin-sensitive currents. The increase of Ik in LA neurons might be one of the protective mechanisms against ischemic insult.

[Evaluation of anti-HCV detection kits using recombinant antigens derived from various HCV regions]

OBJECTIVE

To evaluate the first and second assay kits currently used in blood centers for screening HCV infected blood, and to provide basis for a better match of the two assay kits.

METHODS

Using the newly developed multi-recombinant-HCV-antigen supplementary assay kit, the authors evaluated concurrently the specificity and sensitivity of two domestic and one imported anti-HCV detection kits.

RESULTS

Discrepancy in specificity and sensitivity existed among the two domestic HCV kits, and overall quality was slightly below that of leading or main stream imported HCV kit.

CONCLUSION

The newly developed multi-recombinant-HCV-antigen supplementary assay kit is useful in the evaluation of HCV antibody detection kit currently in use. It provides qualified assessing kit to capture antibodies against various HCV antigens. The present paper provided guidance for selecting a better match of the two screening kits and improved screening efficiency.

Developmental changes of transient potassium currents in large aspiny neurons in the neostriatum

Developmental regulation of the potassium conductance is important for the maturation of neuronal excitability and the formation of functional circuitry in the central nervous system (CNS). The rapidly inactivating A-type current is a major component of the voltage-dependent outward potassium currents in the large aspiny (LA) neurons in the neostriatum. The large aspiny neurons play important roles in the function of neostriatum in physiological and pathological conditions. Whole-cell patch-clamp recording was performed on acutely dissociated neurons and brain slices to investigate the postnatal development of A-type current in the large aspiny neurons. The current density of A-type current in large aspiny neurons was the highest at postnatal 1-3 days and gradually decreased during the development with the lowest levels in adult animals. In comparison to postnatal 1-3 days, the steady-state inactivation curve shifted in depolarizing direction in mature neurons. No significant changes in the voltage dependence of steady-state activation were observed during development. Consistent with the decrease in the current density of A-type current during development, the latency to the first spike was dramatically shortened in mature large aspiny neurons. These results suggest that the decrease of rapidly inactivating A-type potassium current during development might contribute, at least in part, to the maturation of the membrane excitability of large aspiny neurons in the neostriatum.

The neurons of the ground squirrel retina as revealed by immunostains for calcium binding proteins and neurotransmitters

Ground squirrel retinas were immunostained with antibodies against calcium binding proteins (CBPs) and classical neurotransmitters in order to describe neuronal phenotypes in a diurnal mammalian retina and to then compare these neurons with those of more commonly studied nocturnal retinas like cats' and rabbits'. Double immunostained tissue was examined by confocal microscopy using antibodies against the following: rhodopsin and the CBPs, calbindin, calretinin, parvalbumin, calmodulin and recoverin (CB, CR, PV, CM, RV), glycine, GABA, choline acetyltransferase (CHAT) and tyrosine hydroxylase (TOH). In ground squirrel retina, the traditional cholinergic mirror symmetric amacrine cells colocalize CHAT with PV and GABA and faintly with glycine. A second cholinergic amacrine cell type colocalizes glycine alone. CR is found in at least 3 different amacrine cell types. The CR-immunoreactive (IR) cell population is a mixture of glycinergic and GABAergic types. The dopamine cell type IR to tyrosine hydroxylase has the typical morphology of a wide field cell with dendrites in S1 but the "rings" seen in cat or rabbit retina are not as numerous. TOH-IR amacrine cells send large club-shaped processes to the outer plexiform layer. CB and CR are in bipolar cells, A- and B-type horizontal cells and several amacrine cell types. Anti-rhodopsin labels the low density rod photoreceptor population in this species. Anti-recoverin labels cones and some bipolar cells while PKC is found in several different bipolar cell types. One ganglion cell with dendritic branching in S3 is strongly CR-IR. We find no evidence for an AII amacrine cell in the ground squirrel, with either anti-CR or anti-PV. An amacrine cell with similarity to the DAP1-3 cell of rabbit is CR-IR and glycine-IR. We discuss this labeling pattern in relationship to other mammalian species. The differences in staining patterns and phenotypes revealed suggest a functional diversity in the populations of amacrine cells according to whether the retinas are rod or cone dominated.

Choline acetyltransferase is expressed by non-starburst amacrine cells in the ground squirrel retina

We have used immunostaining techniques to reveal a new type of amacrine cell that is immunoreactive for choline acetyltransferase (ChAT), the acetylcholine synthesizing enzyme, in the Ground Squirrel (Spermophilus beecheyi) retina. Cryostat sections and double immunostained wholemount preparations were examined by confocal microscopy. This new ChAT type III cell is distinct in morphology and neurotransmitter content from the well know 'starburst' amacrine cells (types I and II) that are so well represented in the ground squirrel retina [J. Comp. Neurol. 365 (1996) 173-216]. The type III cell colocalizes glycine with the acetylcholine and does not appear to be GABAergic or exhibit calcium-binding proteins like the well-known starburst type. As well, type III cells do not occur as a mirror-symmetric pair with normally placed and displaced varieties. The type III cell is probably a small field amacrine type branching broadly in upper sublamina b of the inner plexiform layer, and is most likely A6 of the Ground Squirrel retina [J. Comp. Neurol. 365 (1996) 173-216]. Type III cells are ideally placed in the architecture of the Ground Squirrel retina to influence ON directionally selective ganglion cell types.

Depression of fast excitatory synaptic transmission in large aspiny neurons of the neostriatum after transient forebrain ischemia

Spiny neurons in the neostriatum die within 24 hr after transient global ischemia, whereas large aspiny (LA) neurons remain intact. To reveal the mechanisms of such selective cell death after ischemia, excitatory neurotransmission was studied in LA neurons before and after ischemia. The intrastriatally evoked fast EPSCs in LA neurons were depressed < or =24 hr after ischemia. The concentration-response curves generated by application of exogenous glutamate in these neurons were approximately the same before and after ischemia. A train of five stimuli (100 Hz) induced progressively smaller EPSCs, but the proportion of decrease in EPSC amplitude at 4 hr after ischemia was significantly smaller compared with control and at 24 hr after ischemia. Parallel depression of NMDA receptor and AMPA receptor-mediated EPSCs was also observed after ischemia, supporting the involvement of presynaptic mechanisms. The adenosine A1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine blocked the inhibition of evoked EPSCs at 4 hr after ischemia but not at 24 hr after ischemia. Electron microscopic studies demonstrated that the most presynaptic terminals in the striatum had a normal appearance at 4 hr after ischemia but showed degenerating signs at 24 hr after ischemia. These results indicated that the excitatory neurotransmission in LA neurons was depressed after ischemia via presynaptic mechanisms. The depression of EPSCs shortly after ischemia might be attributable to the enhanced adenosine A1 receptor function on synaptic transmission, and the depression at late time points might result from the degeneration of presynaptic terminals.

Passively Q-Switched Yb:YAG Laser with Cr(4+):YAG as the Saturable Absorber

By using a continuous-wave Ti:sapphire laser as a pumping source, we demonstrated a passively Q-switched Yb:YAG laser at room temperature with Cr(4+):YAG as the saturable absorber. We achieved an average output power of as much as 55 mW at 1.03 mum with a pulse width (FWHM) as short as 350 ns. The initial transmission of the Cr(4+):YAG has an effect on the pulse duration (FWHM) and the repetition rate of the Yb:YAG passively Q-switched laser. The Yb:YAG crystal can be a most promising passively Q-switched laser crystal for compact, efficient, solid-state lasers.

Laser performance of highly neodymium-doped yttrium aluminum garnet crystals

The laser performance of highly neodymium-doped yttrium aluminum garnet (YAG) crystals is reported. In cw laser-diode pumping, a slope efficiency of 54% was achieved for a 2-at. %-doped sample, which was comparable with the slope efficiency of 55% of YVO(4) . The crystal also exhibited a slope efficiency of 64% under pulsed Ti:sapphire pumping. Such a high efficiency suggests a total cavity loss of ~1% , which is as low as that of commercially available 1-at. % YAG crystal. The excellent performance of the neodymium-doped YAG crystals indicates their high optical quality.

Localization of neurotransmitters and calcium binding proteins to neurons of salamander and mudpuppy retinas

We wished to identify the different types of retinal neurons on the basis of their content of neuroactive substances in both larval tiger salamander and mudpuppy retinas, favored species for electrophysiological investigation. Sections and wholemounts of retinas were labeled by immunocytochemical methods to demonstrate three calcium binding protein species and the common neurotransmitters, glycine, GABA and acetylcholine. Double immunostained sections and single labeled wholemount retinas were examined by confocal microscopy. Immunostaining patterns appeared to be the same in salamander and mudpuppy. Double and single cones, horizontal cells, some amacrine cells and ganglion cells were strongly calbindin-immunoreactive (IR). Calbindin-IR horizontal cells colocalized GABA. Many bipolar cells, horizontal cells, some amacrine cells and ganglion cells were strongly calretinin-IR. One type of horizontal cell and an infrequently occurring amacrine cell were parvalbumin-IR. Acetylcholine as visualized by ChAT-immunoreactivity was seen in a mirror-symmetric pair of amacrine cells that colocalized GABA and glycine. Glycine and GABA colocalized with calretinin, calbindin and occasionally with parvalbumin in amacrine cells.

[Histochemical observation of changes of neurons and axons in injured brainstem]

Brainstem of rats were stabbed with a needle and pathological changes of neurons and axons in brainstem were observed at different time after injury with Nissl's body staining, silver staining and modified trichrome staining. It was found that, by silver staining, the axons showed irregular swelling and disconnection at 1-3 h, marked swelling of the severe end at 6 h, retraction ball at 15 h and remarkable retraction ball at 24 h. By modified trichrome staining, the space between myelin sheaths and axons was widened at 3-6 h, and tortuous myelin sheaths adhered incompletely on axons, or even peeled off at 15 h to 24 h. Perinuclear lysis of Nissl's bodies at 24 h after injury could be seen by Nissl body staining. The results indicated that, the pathological changes in injured brainstem could be observed with histochemical staining, which might be used for timing brainstem injuries.

Biological characterization of uncleavable plasma membrane-anchored human macrophage colony-stimulating factor

The cell-surface form of human macrophage colony-stimulating factor (CSF-1(256), M-CSFalpha) is a plasma membrane-anchored transmembrane protein from which the soluble CSF-1 is released by ectodomain proteolytic cleavage. We have previously generated two forms of cell surface CSF-1 which failed to undergo the cleavage by deleting residues 161-165 or residues 159-165 in the extracellular juxtamembrane region (1). To determine the biologic significance of the ectodomain cleavage, we compared the biosynthesis and biologic activities of uncleavable mutant CSF-1 forms with those of the cleavable wild-type (WT) CSF-1. We found that the uncleavable CSF-1 forms were able to accumulate on cell surface at about threefold higher level than the cleavable WT CSF-1 did. We further demonstrated that the uncleavable plasma membrane-anchored forms of CSF-1 were biologically active in mediating the proliferation of CSF-1-dependent cells as well as the intercellular adhesion between CSF-1 receptor-bearing cells and CSF-1 expressing cells. Furthermore, the adhesive activity of uncleavable CSF-1 forms was about twofold stronger than that of WT CSF-1, which indicated that the ectodomain cleavage system plays an important role in regulating the biologic activities of membrane-anchored CSF-1.

Laser-diode-pumped Cr(4)+, Nd(3)+:YAG with self-Q-switched laser output of 1.4 W

By use of a laser diode as a pump source, a self-Q-switched laser from a Cr, Nd:YAG crystal is demonstrated. The output Q-switched traces are very stable, the threshold pump power is 3.5 W, the pulse duration is 50 ns, and the slope efficiency is as high as 20%. In addition, the pulse width remains constant while the pulse repetition rate varies with pump power.

[Spectroscopy performances of Yb3+ doped YAG crystal]

The absorption and emission properties of Yb:YAG with different Yb3+ doped concentration have been studied systematically. The emission cross section has been evaluated using the absorption cross section and principle of reciprocity, which was consistent with previous reports. The absorption spectra of Yb2+ and color center were observed in as-grown Yb:YAG boules, which are removed by annealing the boules in oxygen at 1,300 degrees C for 24 h. The photon excited and X-ray excited optical luminescence of Yb:YAG were first discussed. The results indicated that Yb:YAG crystal was favourable for high-power diode-pumping.

[Effect of human plasma HDL on the HDL receptors of plasma membranes of cholesterol-fed rabbit]

Atherosclerosis(As) rabbit model was developed by high-cholesterol feeding for 12 weeks. The rabbits were injected intravenously with human plasma HDL preparation per week, and then the effects of HDL on the lipids contents of serum, liver and bile nd the activity of HDL receptors on liver plasma membranes of cholesterol-fed rabbit were investigated. The results showed that HDL preparation had no effect on decreasing the lipids contents of serum, but it could low down the lipid depositions in liver, and promote the excretion of lipids from bile. The value of Bmax of HDL receptor showed decreasing trendy and the value of Kd showed increasing trendy in cholesterol-fed rabbits. In HDL-treated rabbits, the value of Bmax increased significantly as compared with that of normal group(P < 0.05), but the value of Kd showed no difference. The results suggested that human plasma HDL could enhance the activity of HDL receptors on the liver plasma membranes of cholesterol-fed rabbit.

Solution structure of the major alpha-amylase inhibitor of the crop plant amaranth

alpha-Amylase inhibitor (AAI), a 32-residue miniprotein from the Mexican crop plant amaranth (Amaranthus hypochondriacus), is the smallest known alpha-amylase inhibitor and is specific for insect alpha-amylases (Chagolla-Lopez, A., Blanco-Labra, A., Patthy, A., Sanchez, R., and Pongor, S. (1994) J. Biol. Chem. 269, 23675-23680). Its disulfide topology was confirmed by Edman degradation, and its three-dimensional solution structure was determined by two-dimensional 1H NMR spectroscopy at 500 MHz. Structural constraints (consisting of 348 nuclear Overhauser effect interproton distances, 8 backbone dihedral constraints, and 9 disulfide distance constraints) were used as an input to the X-PLOR program for simulated annealing and energy minimization calculations. The final set of 10 structures had a mean pairwise root mean square deviation of 0.32 A for the backbone atoms and 1.04 A for all heavy atoms. The structure of AAI consists of a short triple-stranded beta-sheet stabilized by three disulfide bonds, forming a typical knottin or inhibitor cystine knot fold found in miniproteins, which binds various macromolecular ligands. When the first intercystine segment of AAI (sequence IPKWNR) was inserted into a homologous position of the spider toxin Huwentoxin I, the resulting chimera showed a significant inhibitory activity, suggesting that this segment takes part in enzyme binding.

Multiple factors determine the selection of the ectodomain cleavage site of human cell surface macrophage colony-stimulating factor

Human cell surface macrophage colony-stimulating factor (CSF-1256, M-CSF alpha) is converted to a soluble growth factor by a regulated proteolytic cleavage process at amino acid residues 157-159. We have previously shown that multiple factors specified by the juxtamembrane region determine the cleavage efficiency [Deng, P., Rettenmier, C. W., and Pattengale, P. K. (1996) J. Biol. Chem. 271, 16338-16343]. In the present paper, we studied the effect of various deletion, insertion, and substitution mutations at or near the cleavage site on both the number and size of cleaved CSF-1(256) products to identify the mechanisms by which the cleavage sites are selected. Deletion of regions 161-162 or 163-165, C-terminal to the cleavage site, as well as deletion of region 150-156, N-terminal to the cleavage site, each yielded a single cleavage product that was smaller than that derived from the wild type (WT). In these experiments cleavage apparently occurred at a specific distance from the transmembrane domain. Insertion of three additional residues between the normal cleavage site and the transmembrane domain yielded one major product that was the same size as the processed form of WT CSF-1(256). In this case the selection of the cleavage site was apparently determined by the amino acid sequence of the juxtamembrane region rather than by the distance from the transmembrane domain. Other amino acid substitutions at the cleavage site caused changes in cleavage site selection, providing additional evidence for the role of amino acid sequence in cleavage site selection. Finally, a comparison of cleavage site selection in the presence and absence of tunicamycin treatment showed that N-glycosylation of certain mutant forms of CSF-1(256) sterically interfered with protease accessibility, which in turn had an effect on the selection of the site used for cleavage. Taken together, these results indicate that cleavage site selection is determined by the amino acid sequence of the juxtamembrane region, the distance of the site from the transmembrane domain, and steric accessibility of the protease.

Passively Q-switched Nd:YVO(4) laser with a Cr(4+):YAG crystal saturable absorber

We demonstrate, for the first time as far as we know, a passively Q-switched operation of a Nd:YVO(4) laser in which a Cr(4+):YAG crystal and a laser-diode bar are used as the saturable absorber and the pump source, respectively. Stable laser pulses as short as 28 ns with 20-muJ energy can be generated with this laser, which has the advantages of simplicity, high efficiency, and good long-term stability.

[The carcinogenesis of human cytomegalovirus to mouse cervix]

We plugged the gelfoam impregnated with virus stock solution into mouse cervix with ophthalmic forceps. Mice of Kun-Ming strain were infected with UV-inactivated HCMV (human cytomegalovirus). After 31 weeks, cervical carcinomas were induced in 15% of the infected mice. In another group, infected with UV-inactivated HCMV adding croton oil, the carcinogenesis was 18.8%, but incontrol group, it was 0%. HCMV IE (immediate early) antigen in 12 cancer tissues of UV-inactivated HCMV treated group were all positive, and HCMV IE antibody geometrical average titre in mouse serum of the same group was 1:167.2, but the same two parameters in control group were both negative. The ANAE positive rate of lymphocytes in mouse peripheral blood of UV-inactivated HCMV treated group was 38.9 +/- 6.8%, and of control group was 67.8 +/- 8.0%.

Hemostatic and fibrinolytic response to desmopressin in uremic patients

Desmopressin (DDAVP) 0.3 micrograms/kg was infused in 20 uremic patients with prolong bleeding time. Prior to infusion, the uremic patients had a reduced level of tissue plasminogen activator (t-PA), normal levels of von Willebrand factor antigen (vWF:Ag) and ristocetin cofactor activity (vWF:RCo) and elevated level of factor VIII coagulant activity (FVIII:C). Patients with lower hematocrit or t-PA levels tended to have a longer bleeding time. One hour after DDAVP infusion, the bleeding time was shortened significantly. This improvement was significant in all patient groups irrespective of the high or low initial levels of factor VIII complex components. Plasma levels of FVIII:C, vWF:Ag, vWF:RCo and t-PA all increased significantly. The magnitude of increase in these factors, however, was not significantly correlated with the extent of bleeding time shortening. The multiple regression model for predicting the extent of bleeding time shortening suggested only two variables, viz initial bleeding time and posttreatment FVIII:C activity to be of significance. The present results indicate that the hemostatic response to DDAVP is uniform in uremic patients, regardless of whether the initial activities of factor VIII complex components are high or low. Posttreatment FVIII:C activity appears to play a significant role in the hemostatic action of DDAVP. Furthermore, a depressed fibrinolytic activity was generally observed to concur with the hemostatic defect in uremic patients.