The Physiological Significance of A-Waves in Early Diabetic Neuropathy: Assessment of Motor Nerve Fibers by Neurophysiological Techniques

Objective: This study aimed to investigate how early A-waves could occur in type II diabetes, and what it implied functionally. Methods: We performed conduction velocity distribution (CVD) test in peroneal nerves of 37 type II diabetic patients with normal nerve conduction study (NCS) and 22 age-matched controls. The electrophysiological data and clinical information were analyzed. Results: A-waves were observed in 45.9% of diabetic patients and only in 1 person in healthy controls, all detected in the tibial nerves. The diabetic patients with A-waves showed faster conduction velocity in all quartiles in the motor peroneal nerves compared to the patients without A-waves, and their CVD histograms were shifted to the right side, consisting of a significantly larger percentage of fast conducting fibers. There was no significant difference in the CVD values of the upper extremity nerves among the patients with and without A-waves and the healthy controls. Conclusion: A-waves could occur in type II diabetes as early as when NCS showed normal, and represented as a sign of neuropathy as well as a sign of rescued motor nerve function.

[Effect of benzo(a)pyrene on dopaminergic neurons and α-synuclein in brain and its mechanism involved]

OBJECTIVE

To analyze the effect of benzopyrene on the decrease of dopaminergic neurons, and the increase and aggregation of α-synuclein, which are the pathological features of Parkinson's disease, and to explore its possible mechanisms.

METHODS

Eight-month-old transgenic mice with human SNCA gene were randomly divided into a BaP-exposed group and a control group. BaP and solvent corn oil were injected intraperitoneally to BaP-exposed group and control group respectively, once a day for 60 days. The motor dysfunction of mice was tested by rotarod test. The effects of BaP on the decrease of dopaminergic neurons and increase and aggregation of α-synuclein were observed by immunohistochemistry and Western blot experiments respectively, and the expression of related mRNA was detected by quantitative real-time PCR (qRT-PCR). Twenty genes were tested in the study, mainly related to neurotransmitter transporter (2 genes), neurotransmitter receptor function (10 genes), cellular autophagy (5 genes), and α-synuclein aggregation and degradation (3 genes).

RESULTS

After BaP exposure, the movement time of the mice in the rotarod test was significantly reduced (P<0.05). The substantia nigra dopami-nergic neurons in the mice were significantly reduced, which was 62% of the control group (P<0.05), and the expression of α-synuclein in the midbrain increased, which was 1.36 times that of the control group (P<0.05). After BaP exposure, mRNA expressions of 14 genes in the midbrain of the mice were significantly down-regulated (P<0.05). Alpha-synuclein degradation and cell autophagy (5 genes), neuron transporters (2 genes), and neurotransmitter receptor functions (5 genes) were involved. The expression of one gene, Synphilin-1, was significantly up-regulated (P<0.01), which was related to α-synuclein aggregation.

CONCLUSION

BaP exposure not only inhibited function of neurotransmitter receptor and dopamine transporter, but also interfered cell autophagy, thereby hindering the degradation of α-synuclein, which could lead to decrease of dopaminergic neurons in substantia nigra and increase and aggregation of α-synuclein in midbrain, as the significant pathology of Parkinson's disease. Therefore, BaP exposure may increase the risk of Parkinson's disease.

Risk factors and score for recollapse of the augmented vertebrae after percutaneous vertebroplasty in osteoporotic vertebral compression fractures

Our study demonstrated a high incidence of recollapse of the augmented vertebrae after PVP treatment for OVCFs. A risk score based on all significant factors can predict the rate of recollapse and gain clinical benefits to prevent recollapse in patients at high risk.

BACKGROUND

Recollapse of the augmented vertebrae after percutaneous vertebroplasty (PVP) treatment for osteoporotic vertebral compression fractures (OVCFs) has obtained much attention. However, little is known about risk factors and score for recollapse of the augmented vertebrae.

OBJECTIVE

To determine risk factors and furthermore develop a risk score related to recollapse of the augmented vertebrae after PVP treatment for OVCFs.

METHODS

Patients who were treated with PVP for single OVCFs and met this study's inclusion criteria were retrospectively reviewed. The follow-up period was at least 2 years. Associations of recollapse with co-variates (age, gender, bone mass density [BMD] with a T-score, fracture level, intravertebral cleft [IVC], fracture type, cement volume, cement leakage, leakage into a disc, cement distribution pattern, Non-PMMA-endplate-contact [NPEC], preoperative fracture severity, reduction rate [RR], reduction angle [RA]) were analyzed and a risk score for recollapse was further developed to predict recollapse.

RESULTS

A total of 152 patients were included. Recollapse group was found in 42 (27.6%) patients. Preoperative IVC, solid lump cement distribution pattern, more RR (a cutoff value of 7%) and larger RA (a cutoff value of 3°) was significantly associated with increased risk for recollapse of the augmented vertebrae. A risk score was developed based on the number of risk factors present in each patient. Patients with a score of 4 had an approximately ninefold increased risk of developing recollapse over patients with a score of 0. The receiver operating characteristic curve of the risk score generated an area under the curve of 0.899 (95% CI 0.642-0.836, P = 0.000).

CONCLUSION

A risk score based on preoperative IVC, cement distribution pattern, reduction rate, and reduction angle predicts the rate of recollapse. Additional studies should aim to validate this score and inspect clinical benefits of recollapse prophylaxis in patients at high risk.

Spontaneous activities in baroreflex afferent pathway contribute dominant role in parasympathetic neurocontrol of blood pressure regulation

AIM

To study the dominant role of parasympathetic inputs at cellular level of baroreflex afferent pathway and underlying mechanism in neurocontrol of blood pressure regulation.

METHODS

Whole-cell patch-clamp and animal study were conducted.

RESULTS

For the first time, we demonstrated the spontaneous activities from resting membrane potential in myelinated A- and Ah-type baroreceptor neurons (BRNs, the 1st-order), but not in unmyelinated C-types, using vagus-nodose slice of adult female rats. These data were further supported by the notion that the spontaneous synaptic currents could only be seen in the pharmacologically and electrophysiologically defined myelinated A- and Ah-type baroreceptive neurons (the 2nd-order) of NTS using brainstem slice of adult female rats. The greater frequency and the larger amplitude of the spontaneous excitatory postsynaptic currents (EPSCs) compared with the inhibitory postsynaptic currents (IPSCs) were only observed in Ah-types. The ratio of EPSCs:IPSCs was estimated at 3:1 and higher. These results confirmed that the afferent-specific spontaneous activities were generated from baroreflex afferent pathway in female-specific subpopulation of myelinated Ah-type BRNs in nodose and baroreceptive neurons in NTS, which provided a novel insight into the dominant role of sex-specific baroreflex-evoked parasympathetic drives in retaining a stable and lower blood pressure status in healthy subjects, particularly in females.

CONCLUSION

The data from current investigations establish a new concept for the role of Ah-type baroreceptor/baroreceptive neurons in controlling blood pressure stability and provide a new pathway for pharmacological intervention for hypertension and cardiovascular diseases.

Characterization of Causal Agents of a Novel Disease Inducing Brown-Black Spots on Tender Tea Leaves in China

A novel disease characterized by small brown-black spots (1 to 2 mm in diameter) on tender tea leaves (Camellia sinensis) has been observed in many regions of Hubei Province, China, which severely affects the yield and quality of tea. Tea leaf samples with typical symptoms were collected from three major tea-cultivation regions of Hubei, and were subjected to pathogen isolation for etiological analysis. As a result, 34 Pestalotiopsis isolates were obtained from 20 samples, and they were identified as Pestalotiopsis theae (14 isolates), P. camelliae (12), and P. clavispora (8), determined by morphologies and phylogenetic analysis based on internal transcribed spacer, and partial β-tubulin and translation elongation factor 1-alpha genes. Pathogenicity tests on detached tea leaves showed that no matter what mycelial discs or conidium suspensions were used, inoculation of the Pestalotiopsis fungi could result in small brown-black spots (1 to 2 mm in diameter) on wounded leaves, similar to those observed in the field in the sizes and colors. It also revealed that only P. theae had pathogenicity on unwounded tea leaves, and P. theae and P. clavispora showed significantly higher virulence than P. camelliae. Inoculation test with conidium suspension on intact tea leaves in the field further confirmed that P. theae as the pathogen of brown-black spots. Reisolation of the pathogens from diseased leaves confirmed that the symptom was caused by the inoculation of Pestalotiopsis fungi. The P. theae isolates responsible for brown-black spots were also compared with those for tea gray blight disease in growth rate, pathogenicity, and molecular characteristics in parallel. To our knowledge, this is the first report that the Pestalotiopsis fungi cause brown-black spot disease on tender tea leaves. The results provide important implications for the prevention and management of this economically important disease.

[The impact of ambient fine particulate matter on the blood pressure of an urban population in Shanghai, China: a panel study]

OBJECTIVE

To investigate the impact of particulate matter 2.5 (PM2.5) on the blood pressure of urban residents in Shanghai, China.

METHODS

A panel study was conducted from May 27(th) to June 5(th) 2014 in a cohort of 30 adults in an urban community. Participants were 50-80 years old, had lived in the community for at least 5 years, and had a good health status. Key exclusion criteria were current smoking, smoking during the last 3 years, passive smoking, alcohol consumption, and severe cardiopulmonary disease. A total of 28 participants were eligible. Information on demographic characteristics, including of age, sex, height, weight, education, income and chronic comorbidities were collected. Participants were requested to have six weekly blood pressure measurements. Real-time concentrations of PM2.5 and gaseous pollutants were obtained from a nearby air quality monitor during 40 d. Pearson correlation was applied to analyze the correlation between PM2.5 and SO2, NO2, CO and O3. Linear mixed models were applied to analyze the association between PM2.5 and blood pressure, after controlling for time-related trends, day of the week, mean temperature, relative humidity and individual characteristics.

RESULTS

The mean systolic and diastolic blood pressure was (124.0±15.0) mmHg (1 mmHg=0.133 kPa) and (74.0±7.7) mmHg, respectively. At 24 h before blood pressure measurement, the mean PM2.5, SO2, NO2, O3 and CO concentration were (8.3±4.9), (46.6±12.9) , (79.2±27.4) μg/m(3) and (0.8±0.2) mg/m(3). The Pearson correlation coefficient R, between PM2.5 and O3, SO2, NO2 and CO was 0.79, 0.59, 0.34 and 0.45, respectively, with corresponding P-values of <0.001, 0.006, 0.012 and 0.009, respectively. The significant correlation between PM2.5 and systolic blood pressure occurred at lag 1 day, was strongest at lag 3 day, but attenuated thereafter. A 10 μg/m(3) increase in 3-day average concentrations of PM2.5 was associated with changes of 1.86 (95%CI: 0.62-3.09) mmHg in systolic blood pressure and -0.05 (95%CI: 0.59-0.50) mmHg in diastolic blood pressure.

CONCLUSION

Short-term exposure to PM2.5 may significantly elevate the systolic blood pressure of urban residents in Shanghai.

[Interaction between APOB gene polymorphism and risk factors in coronary heart disease patients without lipid-lowering treatment]

Objective: To investigate the association between APOB gene R532W polymorphism and the risk of coronary heart disease (CHD) in patients without lipid-lowering treatment and to analyze the interactions between the variation of R532W and different risk factors of CHD. Methods: CHD and non-CHD were diagnosed according to coronary artery angiography (CAG) and/or coronary computed tomography angiogram (CTA) results, as well as clinical features. Blood samples from 771 CHD patients and 772 age- and sex-matched non-CHD controls, who never accepted any lipid-lowering treatments, were collected. R532W was genotyped by HumanExome BeadChip at BGI and strict quality control was made. Firstly, the association between R532W polymorphism and the risk of CHD in 3 genetic models (GA+ AA vs.GG, AA vs. GG+ GA, AA vs. GA vs. GG) after adjusting confounding factors was explored. Then, the interactions between the variation of this loci and risk factors related to CHD were investigated. Results: (1) Total cholesterol (TC) levels were significantly lower in AA genotype than in GA genotype in the total cohort and non-CHD controls, but was similar among the 3 genotypes in CHD patients. (2) R532W GG, GA and AA distribution was 80.7%, 18.2% and 1.2% in CHD patients, and 74.6%, 23.8% and 1.6% in non-CHD controls (P<0.05). (3) R532 polymorphism was related to the incidence of CHD in the dominant model, and A-allele carriers were related to about 35% reduced risk of CHD (OR=0.653, 95% CI 0.502-0.849, P=0.001) after adjusting for confounding factors. (4) R532W polymorphism had positive interactions with hypertension (1.452) and smoke (1.077), while negative interaction with diabetes (0.553) in the occurrence of CHD. Conclusions: APOB gene R532W polymorphism is related to TC levels in Chinese north Han population. A-allele carries of R532W loci is linked with reduced risk of CHD in the absence of lipid-lowering treatment. R532W polymorphism has a positive additive interaction with hypertension and smoke, while a negative additive interaction with diabetes mellitus in the occurrence of CHD.

Development and characterization of microsatellite markers for Ulmus chenmoui (Ulmaceae), an endangered tree endemic to eastern China

Ulmus chenmoui (Ulmaceae) is an endangered tree found on Langya Mountain, eastern China. To better understand the population genetics of U. chenmoui and conserve the species, we developed microsatellite markers. Using a suppression-polymerase chain reaction technique, 74 compound microsatellite primer pairs were designed. Twelve microsatellite markers were polymorphic in 39 individuals, and the number of alleles per locus ranged from 3 to 9. The observed and expected heterozygosities ranged from 0.051 to 0.769 and from 0.533 to 0.768, respectively. Significant linkage disequilibrium was detected for three pairs of loci (P < 0.01), which may be due to a recent population bottleneck and the small population size. Nine of the 12 loci deviated from the Hardy-Weinberg equilibrium (P < 0.01), which could be explained by significant inbreeding rather than the presence of null alleles. These markers will provide a solid basis for future efforts in population genetic studies of U. chenmoui, which in turn will contribute to species conservation.

Up-regulation of the Ang II/AT1 receptor may compensate for the loss of gastric antrum ICC via the PI3k/Akt signaling pathway in STZ-induced diabetic mice

The classic renin-angiotensin system (RAS) is a complex system in which angiotensin II (Ang II) has been identified as an important endogenous regulator that influences both smooth muscle contraction and cell growth. Although a local RAS is known to exist in the gastrointestinal tract, it is unclear whether Ang II is involved in the loss of gastric interstitial cells of Cajal (ICC) in diabetic mice. The present study was designed to investigate the effect of Ang II on ICC survival in streptozotocin (STZ)-induced diabetic mice. Western blot, immunofluorescence, isometric muscle recording, enzyme-linked immunosorbent assay (ELISA) and a cell counting kit-8 were used in this research. Our results demonstrate that the c-Kit and membrane-bound stem cell factor (mSCF) protein expression levels in gastric smooth muscle were decreased in STZ-induced diabetic mice. However, the angiotensin receptor type 1 (AT1R) expression levels in gastric smooth muscle and angiotensin-converting enzyme (ACE) expression levels in gastric mucosa were increased. The effect of Ang II on the tonic contraction of gastric smooth muscle was potentiated in diabetic mice, and the plasma Ang II level was enhanced. Ang II increased mSCF expression, cell proliferation, and Akt-Ser473 phosphorylation in cultured gastric smooth muscle cells (GSMCs). These effects were reduced by specific inhibitors ZD7155 (an AT1R antagonist) and LY294002 (a PI3-kinase inhibitor). Our results suggest that Ang II increases mSCF expression and cell proliferation in cultured GSMCs in a PI3K/Akt signaling-dependent manner. ACE and AT1R up-regulation in the stomach may help compensate for ICC loss in STZ-induced diabetic mice.

Sumoylation of the Tumor Suppressor Promyelocytic Leukemia Protein Regulates Arsenic Trioxide-Induced Collagen Synthesis in Osteoblasts

Background/Aims: Promyelocytic leukemia (PML) protein is a tumor suppressor that fuses with retinoic acid receptor-α (PML-RARα) to contribute to the initiation of acute promyelocytic leukemia (APL). Arsenic trioxide (ATO) upregulates expression of TGF-β1, promoting collagen synthesis in osteoblasts, and ATO binds directly to PML to induce oligomerization, sumoylation, and ubiquitination. However, how ATO upregulates TGF-β1 expression is uncertain. Thus, we suggested that PML sumoylation is responsible for regulation of TGF-β1 protein expression. Methods: Kunming mice were treated with ATO, and osteoblasts were counted under scanning electron microscopy. Masson's staining was used to quantify collagen content. hFOB1.19 cells were transfected with siRNA against UBC9 or RNF4, and then treated with ATO or FBS. TGF-β1, PML expression, and sumoylation were quantified with Western blot, and collagen quantified via immunocytochemistry. Results: ATO enhanced osteoblast accumulation, collagen synthesis, and PML-NB formation in vivo. Knocking down UBC9 in hFOB1.19 cells inhibited ATO- and FBS-induced PML sumoylation, TGF-β1 expression, and collagen synthesis. Conversely, knocking down RNF4 enhanced ATO- and FBS-induced PML sumoylation, TGF-β1 expression, and collagen synthesis. Conclusion: These data suggest that PML sumoylation is required for ATO-induced collagen synthesis in osteoblasts.

Protective Effects of Modeled Superoxide Dismutase Coordination Compound (MSODa) Against Ischemia/Reperfusion Injury in Rat Skeletal Muscle

Background/Aim: Ischemia/reperfusion (I/R) injury of skeletal muscles is common pathophysiology during surgeries and the superoxide dismutase (SOD) plays a critical role in this process. SOD-modeled coordination compound (MSODa) may simulate the protective effects as SOD. Methods: Therefore, this study was designed to explore the protective effects and underlying mechanism of MSODa on malondialdehyde (MDA) and integrin-β2 (CD11b/CD18) in plasma, myeloperoxidase (MPO) and intercellular cell adhesion molecule-1 (ICAM-1) in tissue, and morphological changes before and after I/R injury. The rat model of I/R in hind limb was established and randomly divided into sham, ischemia, I/R, I/R-treated with saline, SOD, and MSODa, respectively. Results: These results showed that averaged values for MDA, MPO, CD11b/CD18, and ICAM-1 were significantly increased (P < 0.01 vs ischemia alone) in a time-dependent fashion along with marked tissue remodeling, such as abnormal arrangement of muscular fibers, interstitial edema, vasodilation with no-reflow, inflammatory cells adherent and infiltration, structural changes in mitochondrial, and decrease in glycogens as well. However, all parameter changes induced by I/R injury were reversed, at least partially, by MSODa and SOD treatments and intriguingly, the beneficial/protective effects of MSODa was superior to SOD with an early onset. Conclusion: This novel finding demonstrates that MSODa improves I/R injury of skeletal muscles due at least partially to inhibition of adherent molecule expression and reduction of oxygen free radical formation during I/R pathophysiological processes and this protective action of MSODa was superior to SOD, highlighting the bright future for MSODa in clinical management of tissue I/R injury.

Field evidence for earlier leaf-out dates in alpine grassland on the eastern Tibetan Plateau from 1990 to 2006

Worldwide, many plant species are experiencing an earlier onset of spring phenophases due to climate warming. Rapid recent temperature increases on the Tibetan Plateau (TP) have triggered changes in the spring phenology of the local vegetation. However, remote sensing studies of the land surface phenology have reached conflicting interpretations about green-up patterns observed on the TP since the mid-1990s. We investigated this issue using field phenological observations from 1990 to 2006, for 11 dominant plants on the TP at the levels of species, families (Gramineae-grasses and Cyperaceae-sedges) and vegetation communities (alpine meadow and alpine steppe). We found a significant trend of earlier leaf-out dates for one species (Koeleria cristata). The leaf-out dates of both Gramineae and Cyperaceae had advanced (the latter significantly, starting an average of 9 days later per year than the former), but the correlation between them was significant. The leaf-out dates of both vegetation communities also advanced, but the pattern was only significant in the alpine meadow. This study provides the first field evidence of advancement in spring leaf phenology on the TP and suggests that the phenology of the alpine steppe can differ from that of the alpine meadow. These findings will be useful for understanding ecosystem responses to climate change and for grassland management on the TP.

Involvement of actin microfilament in regulation of pacemaking activity increased by hypotonic stress in cultured ICCs of murine intestine

Distension is a regular mechanical stimulus in gastrointestinal (GI) tract. This study was designed to investigate the effect of hypotonic stress on pacemaking activity and determine whether actin microfilament is involved in its mechanism in cultured murine intestinal interstitial cells of Cajal (ICCs) by using whole-cell patch-clamp and calcium imaging techniques. Hypotonic stress induced sustained inward holding current from the baseline to -650+/-110 pA and significantly decreased amplitudes of pacemaker current. Hypotonic stress increased the intensity of basal fluorescence ratio (F/F0) from baseline to 1.09+/-0.03 and significantly increased Ca(2+) oscillation amplitude. Cytochalasin-B (20 microM), a disruptor of actin microfilaments, significantly suppressed the amplitudes of pacemaker currents and calcium oscillations, respectively. Cytochalasin-B also blocked hypotonic stress-induced sustained inward holding current and hypotonic stress-induced increase of calcium oscillations. Phalloidin (20 microM), a stabilizer of actin microfilaments, significantly enhanced the amplitudes of pacemaker currents and calcium oscillations, respectively. Despite the presence of phalloidin, hypotonic stress was still able to induce an inward holding current and increased the basal fluorescence intensity. These results suggest that hypotonic stress induces sustained inward holding current via actin microfilaments and the process is mediated by alteration of intracellular basal calcium concentration and calcium oscillation in cultured intestinal ICCs.

[Effects of myocardial performance index on assessing left ventricular function in patients with primary hypertension]

OBJECTIVE

To investigate the value of myocardial performance index (MPI) in assessing LV function in patients with primary hypertension (HP).

METHODS

We studied 130 patients with HP (mean age 54.9±13.3 years)and 155 healthy control subjects (mean age 52.4±11.6 years). MPI was determined by tissue doppler imaging using the following formula: MPI=(isovolumic contraction time + isovolumic relaxation time)/ ejection time. The HP group was divided into hypertrophy subgroup( LVMI≥115 g/m(2) in males, or ≥95 g/m(2) in females) and normal mass subgroup(LVMI <115 g/m(2) in males, or<95 g/m(2) in females).

RESULTS

MPI was significantly different in control group, normal mass subgroup and hypertrophy subgroup(0.72±0.23 vs. 0.54± 0.17 vs. 0.45±0.11, P<0.001). Hypertrophy subgroup had significant higher MPI than normal mass subgroup(P =0.046), and both the groups had significant higher MPI than control group(all P<0.001). MPI was positively associated with age(r=0.369,P<0.001), Left ventricular end diastolic diameter(r=0.169, P<0.05), Sm(r=-0.211, P<0.001) and Em(r=-0.383, P<0.001) in control group. In multiple linear regression analysis, MPI was independently related to age (β=0.492, t=7.222,P<0.001) in control group. Among the HP patients, MPI was positively associated with left atrial area (r=0.293, P<0.001),intra ventricular septum(IVS) diameter (r=0.453, P<0.001), LVMI (r=0.453, P<0.001), relative wall thickness(r=0.458, P<0.001), and negatively associated with Sm(r=-0.414, P<0.001), Em(r=-0.508, P<0.001), left ventricular ejection fraction (r=-0.305, P<0.001) in bivariate analysis. In the multiple linear regression analysis, MPI was independently related to Em (β=0.401, t=4.256,P<0.001) and IVS diameter (β=-0.365, t=-3.878,P<0.001) in the HP patients.

CONCLUSION

The HP patients had elevated MPI, especially in the ones with LV hypertrophy. Tissue doppler imaging (TDI) derived MPI could be a useful index to evaluate the overall cardiac function in HP patients.

Arsenic trioxide exerts a double effect on osteoblast growth in vitro

Arsenic trioxide (ATO) is a promising antitumor agent used to treat acute promyelocytic leukemia (APL) and, recently solid tumor. The present study was designed to evaluate the effect of ATO proliferation of osteoblast that plays very important roles in maintaining the structure integrity and function of bone. Cell survives, apoptosis, collagen, and molecular targets were identified by multiple detecting techniques, including MTT assay, electron microscopy, collagen detecting kit, TUNEL kit, and western blot in hFOB1.19 human osteoblasts cell line. The results showed that low dose of ATO (0.25, 0.5, and 1μM) remarkably enhanced the viability of cultured osteoblasts in a concentration- and time-dependent manner. Intriguingly, a dual effect of high dose of ATO (5, 10, and 20μM) was also observed showing significant reduction in viability of culture osteoblasts at concentration- and time-dependent fashion. Moreover, low dose of ATO promoted secretion and synthesis of collagen, whereas high dose of ATO induced typical morphological characteristics of apoptosis in osteoblasts. Mechanically, western blot results demonstrated that low dose of ATO dramatically up-regulated TGF-β1 protein and activated p-AKT proliferative signaling. And, high dose of ATO increased Bax/Bcl-2 ratio in a time-dependent fashion and activated caspase-3 apoptotic signaling. These results demonstrate at the first time that ATO exerts a double effect on osteoblast function depending upon the concentration and provide a clue to rationally use ATO for clinicians to pay more attention to protect bone from the adverse effects of therapeutic dose of ATO during tumor therapy.

A comparison of osteocyte bioactivity in fine particulate bone powder grafts vs larger bone grafts in a rat bone repair model

The osteogenic potential for bone grafts is based on numbers and activities of cells that survive transplantation. In this study, we compared the bioactivity of osteocytes in 300-500 μm fine particulate bone powder grafts to 2 mm larger bone grafts in a rat radial defect model. Expression levels of bone morphogenetic protein-2 (BMP-2), transforming growth factor-beta 1 (TGF-β1), alkaline phosphatase (ALP), and collagen I were semi-quantified by both immunohistochemistry and RT-PCR at days 1 and 4, as well as weeks 1, 2, 4, 6 and 10 post-transplantation. Within two weeks post-transplantation, more cells stained positively for BMP-2, TGF-β1, ALP, and collagen I within the bone grafts and in the surrounding tissues in the group transplanted with the fine particulate bone powder grafts than in those with larger bone grafts (P<0.05). The mRNA levels of all four markers in the group transplanted with fine particulate bone powder graft peaked earlier and were expressed more highly than in the larger bone graft group, suggesting that fine particulate bone powder grafts provide more viable and active osteocytes to accelerate bone defect healing than larger bone grafts.

First Report of Alternaria alternata Causing Leaf Spots of Tea (Camellia sinensis) in China

Tea is the most popular non-alcoholic beverage crop in the world, which originated in China and has been cultivated in over 45 countries. In recent years, a leaf spot disease of unknown etiology has been observed on young leaves of tea trees (Camellia sinensis) grown in Luotian county, Hubei Province, China. Observed symptoms display grayish brown to white spots (about 1 cm in diameter) surrounded by brown edges. Over 20% of the young leaves were affected on surveyed trees. To identify the pathogen, six symptomatic tea leaves were collected from six individual tea trees of unknown variety in August 2012. A thin section (3 to 5 mm) of symptomatic tissue was sterilized in a bleach solution of 3% hypochlorite and placed on potato dextrose agar (PDA) medium at 25°C in darkness for isolation. Six fungal colonies displaying gray-brown and gray-white aerial mycelia were consistently recovered from lesions of the six leaves, termed as T1 to T6, respectively. Conidia produced on the colonies were olive brown, obpyriform, short conical beak at the tip, 0 to 3 vertical and 1 to 6 transverse septa, and length × width of 7.1 to 31.7 (avg. 20.1) × 2.9 to 12.7 (avg. 7.2) μm. T1 to T6 were identified as Alternaria alternata on the basis of morphological characterization, respectively (2). Confirmation of the species identification was obtained by molecular characterization of their internal transcribed spacer (ITS) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) regions amplified from the genomic DNAs using the universal primers (1). The results revealed identical sequences of ITS (GenBank Accession No. KF699530) and GAPDH among the six isolates. BLAST searches showed that they had the highest similarity with A. alternata strains, with 98.3% for ITS (AJ276055) and 96.2% for GAPDH (EF513205), deposited in fungus database ( http://www.mycobank.org/ ). Pathogenicity tests were conducted on the detached leaves expanding for 10 to 20 days of two tea varieties (cvs. Fudingdabai and Taicha No. 12) in triplicate by placing 4 mm diameter discs from 5-day-old PDA plates of T3 and T6, which were incubated in an incubator at 25°C with a 12-h photoperiod for 7 days. All inoculated leaves with or without wound treatment developed brown spots similar to the original ones at 7 days post inoculation (dpi) while the control leaves inoculated with non-colonized PDA plugs remained asymptomatic. Isolates recovered from diseased samples were of the same morphology and ITS sequence as the inoculated ones. Alternaria alternata had been described on C. sinensis in China (3), but it was only reported as a severe foliar fungal pathogen of tea in North Bengal, India (1), and to our knowledge, this is the first report of A. alternata causing leaf spots on tea leaves (C. sinensis) in China. In addition to quantity loss, the species may result in a decrease of quality of tea crop considering that it can produce Alternaria toxins related to animal and public health. The etiologic identification of the disease is expected to provide useful information for its control. References: (1) B. N. Chakraborty et al. Plant Pathol. 55:303, 2006. (2) E. G. Simmons. Page 1 in: Alternaria Biology, Plant Diseases and Metabolites. J. Chelchowski and A. Visconti, eds. Elsevier, Amsterdam, 1992. (3) F. L. Tai. Page 1527 in: Sylloge Fungorum Sinicorum. eds. Sci. Press Acad. Sin. Beijing, 1979. (4) B. S. Weir et al. Stud. Mycol. 73:115, 2012.

First Report of Valsa leucostoma Causing Valsa Canker of Pyrus communis (cv. Duchess de' Angouleme) in China

Pear is a popular fruit in the world market, and has been widely cultivated in China. Since 2008, a severe canker disease has consistently been observed on 20-year-old pear trees (Pyrus communis cv. Duchess de' Angouleme) grown in a nursery in Xingcheng, Liaoning Province, China. Observed symptoms include brown elongated ulcerative lesions (more than 20 cm in length in general), with red brown conidia produced on wet lesions. Reductions in tree vigor and yield were observed for infected trees. Tree mortality was observed for severe infections. To diagnose the pathogen, 15 canker samples were collected from five pear trees in April, 2012. Bark pieces (3 to 5 mm) taken from the border of healthy and diseased tissue were surface-disinfected with 0.1% mercury bichloride and 75% ethanol for 45 s, and placed on potato dextrose agar (PDA) medium at 25°C in darkness. Fungal colonies with a common colony morphology were consistently recovered from three samples. These fungal colonies were initially white, becoming olive green in 3 days. Conidia produced on colonies were hyaline, allantoid, and single-celled with average length × width of 6.04 (5.43 to 6.59) × 0.65 (0.51 to 0.73) μm, which were consistent with descriptions of Valsa leucostoma (1). Genomic DNA was extracted from a representative isolate F-LN-32b, and subjected to PCR amplification of the internal transcribed spacer region (ITS), β-tubulin gene, and EF1 gene using the primer pairs ITS1/ITS4, Bt2a/Bt2b and EF1-728F/EF1-986R (3), respectively. Sequence alignment of the amplified fragments with the deposited data in NCBI showed that sequences of EF1, ITS, and β-tubulin (GenBank Accession No. KF293296 to KF293298, respectively) of isolate F-LN-32b had the highest similarity of 99% to those of V. leucostoma strain 32-2w (JQ900340, JN584644, and JQ900374), and suggested that isolate F-LN-32b is a V. leucostoma strain. Pathogenicity tests was carried out by placing a 5-mm-diameter, 2-day-old mycelium agar plug of isolate F-LN-32b onto a punched bark hole of a detached 1-year-old pear shoot after it was surface disinfested with ethanol. Inoculated shoots were incubated at 25°C in plastic containers covered with plastic film. Pathogenicity assays were conducted on 18 pear varieties (cvs. Qiuyue, Jinshui 2, Hohsui, Huali 1, Cuiguan, Shinseiki, Xuehua, Dangshansu, Zaosu, Hongxiangsu, Yuluxiang, Nanguoli, Xizilv, Bartlett, Huanghua, Huashan, Duchess de' Angouleme, and Packham's) collected from a nursery in Wuhan, Hubei Province, China. Six shoots were inoculated for each variety and the assay was conducted three times. All inoculated shoots developed the typical canker symptoms after 6 days post inoculation (dpi) and sporulated at 25 dpi while the control shoots inoculated with non-colonized PDA plugs remained asymptomatic. Isolates recovered from inoculated samples were of the same morphology and ITS sequence as F-LN-32b. Based on these results, V. leucostoma was determined as the pathogen responsible for the Valsa canker disease on pear. Valsa mali var. pyri was identified as the only pathogen causing Valsa canker disease on pear in China (2). To our knowledge, this is the first report of V. leucostoma causing a canker disease on pear in China. References: (1) G. C. Adams et al. Australas. Plant Pathol. 35:521, 2006. (2) X. L. Wang et al. Mycologia 103:317, 2011. (3) T. J. White et al. Pages 315-322 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990.

Gender differences in histamine-induced depolarization and inward currents in vagal ganglion neurons in rats

Evidence has shown gender differences regarding the critical roles of histamine in the prevalence of asthma, anaphylaxis, and angina pectoris. Histamine depolarizes unmyelinated C-type neurons without any effects on myelinated A-type vagal ganglion neurons (VGNs) in male rats. However, little is known if VGNs from females react to histamine in a similar manner. Membrane depolarization and inward currents were tested in VGNs isolated from adult rats using a whole-cell patch technique. Results from males were consistent with the literature. Surprisingly, histamine-induced depolarization and inward currents were observed in both unmyelinated C-type and myelinated A- and Ah-type VGNs from female rats. In Ah-type neurons, responses to 1.0 μM histamine were stronger in intact females than in males and significantly reduced in ovariectomized (OVX) females. In C-type neurons, histamine-induced events were significantly smaller (pA/pF) in intact females compared with males and this histamine-induced activity was dramatically increased by OVX. Female A-types responded to histamine, which was further increased following ovariectomy. Histamine at 300 nM depolarized Ah-types in females, but not Ah-types in OVX females. In contrast, the sensitivity of A- and C-types to histamine was upregulated by OVX. These data demonstrate gender differences in VGN chemosensitivity to histamine for the first time. Myelinated Ah-types showed the highest sensitivity to histamine across female populations, which was changed by OVX. These novel findings improve the understanding of gender differences in the prevalence of asthma, anaphylaxis, and pain. Changes in sensitivity to histamine by OVX may explain alterations in the prevalence of certain pathophysiological conditions when women reach a postmenopausal age.

Remodeling of hyperpolarization-activated current, Ih, in Ah-type visceral ganglion neurons following ovariectomy in adult rats

Hyperpolarization-activated currents (I_h) mediated by hyperpolarization-activated cyclic nucleotide-gated (HCN) channels modulate excitability of myelinated A− and Ah-type visceral ganglion neurons (VGN). Whether alterations in I_h underlie the previously reported reduction of excitability of myelinated Ah-type VGNs following ovariectomy (OVX) has remained unclear. Here we used the intact nodose ganglion preparation in conjunction with electrophysiological approaches to examine the role of I_h remodeling in altering Ah-type neuron excitability following ovariectomy in adult rats. Ah-type neurons were identified based on their afferent conduction velocity. Ah-type neurons in nodose ganglia from non-OVX rats exhibited a voltage ‘sag’ as well as ‘rebound’ action potentials immediately following hyperpolarizing current injections, which both were suppressed by the I_h blocker ZD7288. Repetitive spike activity induced afterhyperpolarizations lasting several hundreds of milliseconds (termed post-excitatory membrane hyperpolarizations, PEMHs), which were significantly reduced by ZD7288, suggesting that they resulted from transient deactivation of I_h during the preceding spike trains. Ovariectomy reduced whole-cell I_h density, caused a hyperpolarizing shift of the voltage-dependence of I_h activation, and slowed I_h activation. OVX-induced I_h remodeling was accompanied by a flattening of the stimulus frequency/response curve and loss of PEMHs. Also, HCN1 mRNA levels were reduced by ∼30% in nodose ganglia from OVX rats compared with their non-OVX counterparts. Acute exposure of nodose ganglia to 17beta-estradiol partly restored I_h density and accelerated I_h activation in Ah-type cells. In conclusion, I_h plays a significant role in modulating the excitability of myelinated Ah-type VGNs in adult female rats.

Subtype identification in acutely dissociated rat nodose ganglion neurons based on morphologic parameters

Nodose ganglia are composed of A-, Ah- and C-type neurons. Despite their important roles in regulating visceral afferent function, including cardiovascular, pulmonary, and gastrointestinal homeostasis, information about subtype-specific expression, molecular identity, and function of individual ion transporting proteins is scarce. Although experiments utilizing the sliced ganglion preparation have provided valuable insights into the electrophysiological properties of nodose ganglion neuron subtypes, detailed characterization of their electrical phenotypes will require measurements in isolated cells. One major unresolved problem, however, is the difficulty to unambiguously identify the subtype of isolated nodose ganglion neurons without current-clamp recording, because the magnitude of conduction velocity in the corresponding afferent fiber, a reliable marker to discriminate subtypes in situ, can no longer be determined. Here, we present data supporting the notion that application of an algorithm regarding to microscopic structural characteristics, such as neuron shape evaluated by the ratio between shortest and longest axis, neuron surface characteristics, like membrane roughness, and axon attachment, enables specific and sensitive subtype identification of acutely dissociated rat nodose ganglion neurons, by which the accuracy of identification is further validated by electrophysiological markers and overall positive predictive rates is 89.26% (90.04%, 76.47%, and 98.21% for A-, Ah, and C-type, respectively). This approach should aid in gaining insight into the molecular correlates underlying phenotypic heterogeneity of nodose ganglia. Additionally, several critical points that help for neuron identification and afferent conduction calibration are also discussed.

First Report of Colletotrichum fructicola Causing Bitter Rot of Pear (Pyrus bretschneideri) in China

Pyrus bretschneideri cv. Dangshansuli is the most important commercial Asiatic pear cultivar worldwide. In recent years, a fruit rot disease of unknown etiology have caused considerable fresh market losses in the 'Dangshansuli' production operations in Dangshan county, Anhui Province, China. Fresh market losses typically range from 60 to 90% and in 2008 were estimated at US$150 million. Symptomatic mature 'Dangshansuli' pears were collected from an orchard in Dangshan County in February 2008. A thin section (about 1 mm³) of symptomatic tissue was sterilized in a bleach and placed on potato dextrose agar (PDA) medium for isolation. From all fruit, a single fungus was recovered displaying gray-white dense aerial mycelium. Identical fungi were isolated from six additional symptomatic 'Dangshansuli' pears collected from other orchards in the county. Pathogenicity tests using one isolate (DS-0) were conducted in triplicate by placing 4 mm diameter discs from 7-day-old PDA plates onto the mature 'Dangshansuli' pear fruit that were incubated in an incubator at 25°C with a 12-h photoperiod for 30 days. An equal number of noncolonized PDA inoculations were included as a control. Isolate DS-0 caused symptoms similar to those in the field within 7 days and complete collapse of cortical tissues within 30 days. No symptoms were observed on control fruit. Round brownish lesions with a diameter of about 3 cm on inoculated fruit was populated by sunken, rotiform acervuli on which numerous, colorless, oblong single cell shape conidia with width/length of 6 × 20 μm were produced. A comparison of morphology and sequence analysis of the ribosomal internal transcribed spacer (ITS) regions in pre- and post-inoculation cultures from inoculated fruit confirmed the presence DS-0. To further characterize DS-0, aliquots of extracted genomic DNA from the fungus were subjected to PCR amplification and sequencing of seven gene regions from the ITS, actin (ACT), β-tubulin 2 (TUB2), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), manganese-superoxide dismutase (SOD2), chitin synthase (CHS-1), and calmodulin (CAL), using the primers listed by Weir et al (4), except for the primer pair of ITS1 (5'-TCCGTAGGTGAACCTGCGG-3') and ITS4 (5'-TCCTCCGCTTATTGATATGC-3') for ITS amplification, and SODglo2-R (5'-TAGTACGCGTGCTCGGACAT-3') and SODglo2-R (5'-TAGTACGCGTGCTCGGACAT-3') for TBU2 amplification. Two or three clones of PCR products of each gene were sequenced and compared (GenBank Accession Nos. KC410780 to KC410786) to published data at http://www.cbs.knaw.nl/colletotrichum . The result indicated that DS-0 shared the highest similarity of 99.91% with Colletotrichum fructicola, corroborating numerous reports of Colletotrichum spp. causing bitter rot of pear on P. pyrifolia (1,2,3,4). C. fructicola was only recently reported as causing bitter rot of P. pyrifolia (4) and to our knowledge, this is the first report of C. fructicola causing bitter rot of P. bretschneideri, which will help producers select the best management practices for this devastating disease. References: (1) P. F. Cannon et al. Stud. Mycol. 73:181, 2012. (2) N. Tashiro et al. J. Gen. Plant Pathol. 78:221, 2012. (3) G. K. Wan et al. Mycobiology 35:238, 2007. (4) B. S. Weir et al. Stud. Mycol. 73:115, 2012.

First Report of Plum bark necrosis stem pitting-associated virus in Stone Fruit Trees in China

Plum bark necrosis and stem pitting disease was first observed on a 'Black Beaut' plum (Prunus salicina Lindl.) in the United States in 1986 and later is several other countries. Plum bark necrosis stem pitting-associated virus (PBNSPaV; genus Ampelovirus, family Closteroviridae), the putative causal agent of the disease, infects many stone fruit species and causes decline, gummosis, flattening of scaffold branches, and stem necrotic pits in some diseased trees (1,3). An investigation of the incidence of PBNSPaV on stone fruit trees in China was conducted during 2009 and 2010. Leaf samples were collected from 47 trees, including peach (P. persica L. Batsch), nectarine (P. persica L. var. nucipersica Schneider), plum (P. domestica L.), ornamental plum (P. cerasifera Ehrb), sweet cherry (P. avium L.), and flowering cherry (P. serrulata L.), grown in Hubei, Henan, and Shandong provinces in central and northern China. Most of sampled trees showed trunk gummosis or stem pitting. The presence of PBNSPaV was tested by reverse transcription (RT)-PCR using primer set PBN195F/PBN195R (5'-CTGGTCTTCCTGCTACTCCTT-3'/5'-AAGCCCACAATCTCAGAGCG-3') designed for the detection of the coat protein (CP) gene of the virus. Total RNA was extracted from leaves using a CTAB protocol reported by Li et al. (2). Products of the expected size of 190 bp were amplified from 20 samples, including seven cultivated peach, four ornamental peach, one nectarine, two plum, one ornamental plum, three sweet cherry, and two flowering cherry samples. All trees positive for PBNSPaV showed stem pitting symptoms on the base of the trunk. To further confirm these results, a 590-base region of the heat shock protein 70 homolog (HSP70h) gene was amplified by RT-PCR using primers HSP-P1/HSP-P2 (5'-GGAATTGACTTCGGTACAAC-3'/5'-TCGAAAGTACCACCACCGAA-3'). Amplicons of the expected size were cloned into the vector pMD18-T (TaKaRa, Dalian, China) and sequenced by Genscript Corp. (Nanjing, China). Sequences of 18 PBNSPaV isolates were deposited in GenBank with Accession Nos. JF810177-JF810194. Sequence comparisons showed that the partial HSP70h gene from the Chinese PBNSPaV isolates shared 82.2 to 100% nucleotide (nt) and 94.0 to 100% amino acid (aa) similarities between them and 83.6 to 99.1% nt and 94 to 100% aa similarities with the corresponding region of the other PBNSPaV isolates deposited in GenBank. In July 2010, peach GF305 seedlings were inoculated by side grafting with budwoods from two PBNSPaV-positive ornamental peach plants. In June 2011, grooving symptom was observed on the stems of the seedlings and the virus was detected by RT-PCR. The results further confirmed PBNSPaV infection in China. These results show that PBNSPaV and the associated disease occur in main cultivated and ornamental Prunus species in China. Given the importance and the devastating symptoms of the disease, it is important to prevent virus spread by using virus-tested propagation materials. References: (1) M. Al Rwahnih et al. Arch. Virol. 152:2197, 2007. (2) R. Li et al. J. Virol. Methods 154:48, 2008. (3) D. B. Marini et al. Plant Dis. 86:415, 2002.

First Report of Citrus exocortis viroid from Grapevine in China

Citrus exocortis viroid (CEVd) can induce bark scaling, dwarfing, leaf epinasty, and fruit yield loss in susceptible hosts. In citrus, CEVd is reported from around the world, but in grape, it is reported from fewer locations (Australia, Brazil, California, and Spain [1]). In 2009, leaves were collected from 40 grapevines (of several different cultivars and species) from Henan, Hubei, Shandong, and Liaoning provinces, China. Total RNA or double-stranded RNA was extracted from the leaves by a described method (3) and subjected to reverse transcription with a random primer (Takara, Dalian, China) and then PCR with primer CEV-AM3 and CEV-AP3 (2). Results showed that the target DNA fragments of 372 bp long were amplified only from the symptomless leaves collected from two grapevines of cv. White Rose grown for approximately 26 years within a small garden in Hubei Province. Amplified products were recovered and cloned into pMD18-T (Takara) and 10 positive clones of each isolate were sequenced and aligned. For both isolates, 20% of the clones represented the same variant (CEVd-hn-g-1; GenBank Accession No. GU592444). It showed a max identity of 94 to 99% with the variants (GenBank Accession Nos. Y00328.1 and DQ471996.1) from grape registered in NCBI, 91 to 100% (GenBank Accession Nos. DQ431993.1 and DQ831485.1) from citrus, 91 to 98% (GenBank Accession Nos. EF488068.1 and EF488050.1) from broad bean, and 89 to 94% (GenBank Accession Nos. AY671953.1 and S67446.1) from tomato. To our knowledge, this is the first report of CEVd from grape in China. References: (1) M. Eiras et al. Fitopatol. Bras. 31:440, 2006. (2) H. J. Gross et al. Eur. J. Biochem. 121:249, 1982. (3) W. X. Xu et al. J. Virol. Methods 135:276, 2006.

First Report of Onion yellow dwarf virus in Allium chinense in China

Allium chinense (G. Don) is an economically important vegetable that has been considered to be of Asian origin (2). In April of 2007, plants of cultivated A. chinense showing mosaic, chlorotic streak, twist, and crinkle on leaves were collected from fields at Jiangxia, a suburban district of Wuhan, Hubei Province, China, and transplanted into pots in a greenhouse. Ultrathin sections of diseased leaves were observed under an electron microscope. Pinwheel or cylindrical inclusions, typical of a potyvirus infection, were observed. Filamentous virus particles (820 nm long) were also observed in the crude extract from the same plant. To identify the virus species, viral RNAs were extracted from partially purified virion preparation (3) and used as a template. First-strand cDNA was synthesized with M4-T (5'-GTT TTC CCA GTC ACG AC (T)₁₅-3') as a complementary primer. The 3'-terminus of viral RNA was amplified using primer M4 (5'-GTT TTC CCA GTC ACG AC-3') in combination with a degenerate primer (5'-GGXAAYAAYAGY GGX CARCC-3') that was specific for potyviruses (1). Amplified products were cloned and nine clones were sequenced. Sequence analysis showed that the size of the amplified fragment, excluding the poly A tail, was 1,625 bp, which had the typical characteristics of the 3'-terminus of the potyvirus genome, including the partial NIb gene (636 bp) and the complete coat protein (CP gene; 771 bp). The 1,625-bp sequence from A. chinense (Genbank Accession No. FJ765739) had the highest identity at the nucleotide level with sequences of Onion yellow dwarf virus (OYDV), ranging from 76% (Genbank Accession Nos. AB219833 and AB219834) to 99% (Genbank Accession No. AJ409313). The CP gene had 88% (Genbank Accession Nos. AB219833 and AB219834) to 99% (Genbank Accession Nos. AJ409313 and AJ409310) identity at the amino acid level with corresponding regions of known OYDV isolates from other hosts. Until now, only Scallion mosaic virus (ScaMV), in the genus Potyvirus, had been detected from A. chinense (1); however, OYDV was reported in rakkyo, the same species as Chinese scallion, in Japan (4). To our knowledge, this is the first report of OYDV infecting A. chinense in China. References: (1) J. Chen et al. Arch. Virol. 147:683, 2002. (2) L. K. Mann and W. T. Stearn. Econ. Bot. 14:69, 1960. (3) T. Nagakubo et al. Phytopathology 84:640,1994. (4) I. Sako et al. Ann. Phytopathol. Soc. Jpn. 57:65, 1991.

Absence of flexor digitorum superficialis tendon in the little finger is not associated with decreased grip strength

We examined the little finger in 402 normal subjects for the presence or absence of the flexor digitorum superficialis. All subjects also had their grip strength measured. No statistically significant difference was seen in the grip strength measurements between subjects who had a flexor digitorum superficialis tendon to the little finger and those who did not. This study demonstrates that absence of the flexor digitorum superficialis to the little finger is not associated with decreased grip strength. The implications of this in terms of repair of the flexor digitorum superficialis of the little finger are considered.

Pacemaker currents modulated by C-type natriuretic peptide in interstitial cells of cajal from murine small intestine

Although the presence of C-type natriuretic peptide (CNP) in gastrointestinal tract has been demonstrated, the effect of CNP on interstitial cells of Cajal (ICC), pacemaker cells in gastrointestinal tract, is still unclear. This study was designed to investigate the effect of CNP on pacemaker currents of ICC and possible mechanisms. We used immunocytochemistry techniques to exhibit natriuretic peptide receptors (NPR) and recorded membrane currents by using whole-cell patch clamp technique on cultured ICC. Our experiment showed that NPR-A and NPR-B were expressed in ICC from murine small intestine. Whole cell recordings further showed that the amplitude of pacemaker currents in intestinal small networks of ICC was 322+/-22pA and the frequency was 16.25+/-0.95Hz. CNP significantly reduced the amplitude of pacemaker currents in small networks of ICC in a dose-dependent manner, and the amplitude was inhibited by 23.95%, 61.76% and 81.67%, the amplitude values in 329+/-28.0pA, 311.2+/-14.8pA and 295+/-26.5pA before treatment with CNP and 237.9+/-27.5pA, 119.6+/-18.5pA and 57.2+/-13.5pA after treatment with 0.01 micromolxL(-1), 0.1 micromolxL(-1) and 1pmolxL(-1) CNP, respectively. The frequencies of pacemaker currents were also significantly reduced from 16.25+/-0.95Hz of control to 13+/-0.9Hz, 12+/-0.8Hz and 3+/-0.2Hz by 0.01micromolxL 1, 0.1micromolxL(-1) and 1 micromol x L(-1) CNP, respectively. CNP also inhibited the amplitude of pacemaker currents in single ICC. The inhibitory effect of CNP was mimicked by 8-Br-cGMP, a membrane permeable cGMP analogue, which suggests that CNP could inhibit pacemaker currents via NPR-B-particulate guanylate cyclase (pGC)-cGMP signal pathway.

Inhibitory effect of C-type natriuretic peptide on L-type calcium channel currents in gastric antral myocytes of guinea pigs

The role of C-type natriuretic peptide (CNP) in the gastrointestinal tract is still unclear. This study was designed to investigate the effect of CNP on barium current (I(Ba)) through the L-type calcium channel in gastric antral myocytes of guinea pigs. The whole-cell patch clamp technique was performed in gastric antral myocytes isolated by collagenase in guinea pigs. CNP significantly inhibited I(Ba) in a dose-dependent manner at the concentrations of 0.001, 0.01, and 0.1 micromol/l, CNP inhibited I(Ba) to 81.56 +/- 2.48 %, 73.64 +/- 3.65 %, and 57.77 +/- 4.93 % of control at 0 mV, respectively. The values of steady-state half-inactivation voltage (33.6 +/- 2.6 mV and 33.8 +/- 3.4 mV, in control and CNP groups, respectively) or the half-activation voltage (-12.6 +/- 2.2 mV and 12.4 +/- 1.8 mV) of I(Ba) were not significantly changed (p > 0.05, n = 6). 8-br-cGMP (1 mmol/l) mimicked the effect of CNP on I(Ba), and the peak current of I(Ba) was inhibited from -403.84 +/- 61.87 pA to 318.94 +/- 67.17 pA (p < 0.05, n = 5). In the presence of LY83583 (0.1 micromol/l), a nonspecific inhibitor of guanylate cyclase, CNP (0.1 micromol/l)-induced inhibition of I(Ba) was partially blocked (n = 13, p < 0.05 ). However, when the cell was pretreated with zaprinast (0.1 micromol/l), an inhibitor of cyclic guanosine monophosphate (cGMP) sensitive phosphoesterase, the inhibitory effect of CNP on I(Ba) was significantly potentiated (n = 11, p < 0.05). KT5823 (1 micromol/l), a cGMP-dependent protein kinase (PKG) inhibitor, almost completely blocked CNP-induced inhibition of I(Ba). The results suggested that CNP can inhibit L-type calcium channel currents, and the inhibitory effect is mediated by pGC-cGMP-PKG-dependent signal pathway in gastric antral myocytes of guinea pigs.

Bicyclic and tricyclic thiophenes as protein tyrosine phosphatase 1B inhibitors

A novel pyridothiophene inhibitor of PTP1B was discovered by rational screening of phosphotyrosine mimics at high micromolar concentrations. The potency of this lead compound has been improved significantly by medicinal chemistry guided by X-ray crystallography and molecular modeling. Excellent consistency has been observed between structure-activity relationships and structural information from PTP1B-inhibitor complexes.

EDAG regulates the proliferation and differentiation of hematopoietic cells and resists cell apoptosis through the activation of nuclear factor-κB

Erythroid differentiation-associated gene (EDAG) is considered to be a human hematopoiesis-specific gene. Here, we reported that downregulation of EDAG protein in K562 cells resulted in inhibition of growth and colony formation, and enhancement of sensitivity to erythroid differentiation induced by hemin. Overexpression of EDAG in HL-60 cells significantly blocked the expression of the monocyte/macrophage differentiation marker CD11b after pentahydroxytiglia myristate acetate induction. Moreover, overexpression of EDAG in pro-B Ba/F3 cells prolonged survival and increased the expression of c-Myc, Bcl-2 and Bcl-xL in the absence of interleukin-3 (IL-3). Furthermore, we showed that EDAG enhanced the transcriptional activity of nuclear factor-kappa B (NF-kappa B), and high DNA-binding activity of NF-kappa B was sustained in Ba/F3 EDAG cells after IL-3 was withdrawn. Inhibition of NF-kappa B activity resulted in promoting Ba/F3 EDAG cells death. These results suggest that EDAG regulates the proliferation and differentiation of hematopoietic cells and resists cell apoptosis through the activation of NF-kappa B.

Isolation and Characterization of EDAG-1, A Novel Gene Related to Regulation in Hematopoietic System

A novel gene, named embryonic develop associated gene 1 ( EDAG -1) and abundantly expressed in human fetal liver tissues, was isolated by screening a human fetal liver cDNA library and the 5' RACE. The full length of EDAG-1 mRNA is 2 166 bp, with an open reading frame of 1 452 bp neucleotides, encoding a 484 amino acid protein. No domain or motif was found similar with other genes by Blast program. Two copies of AUUUA motif in 3' non-translated region show instability of its mRNA. The molecular weight of the protein is 55.3 kD identified by the translation in vitro. EDAG-1 is specifically expressed in hematopoietic tissues, and is quickly down-regulated during the differentiation of K562 cells induced by hemin and EPO. These results show that EDAG-1 is related to the regulation in hematopoietic system and the development of leukemia.

Increment of calcium-activated and delayed rectifier potassium current by hyposmotic swelling in gastric antral circular myocytes of guinea pig

AIM

To observe the effect of hyposmotic swelling on calcium-activated potassium current [IKCa] and delayed rectifier potassium current [IKV] in gastric antral circular myocytes of guinea pig.

METHODS

The whole cell patch-clamp technique was used, and the myocytes were isolated by collagenase. Cells were swelled by the hyposmotic solution (200 Osmmol/kg).

RESULTS

The hyposmotic solution markedly increased IKCa and IKV. The increase of IKCa was markedly inhibited by tetrathylammonium (TEA) 4 mmol/L and charybdotoxin (ChTX) 200 nmol/L. The increase of IKV was incompletely blocked by TEA and completely blocked by 4-aminopyridine (4-AP) 10 mmol/L. There was no significant difference between the amplitudes of the increase of IKCa and IKV (P < 0.05). IKCa increased (17.0 +/- 4.8) s after the cells were perfused with the hyposmotic solution, whereas IKV increased (30.7 +/- 13.7) s after the cells exposed to the hyposmotic solution. There was significant difference between the latency of IKCa and IKV (P < 0.05).

CONCLUSION

Hyposmotic swelling increased both IKCa and IKV, and the increment was likely related to the cell volume regulation.

[Isolation of specific expression gene in human fetal liver by representational difference analysis]

AIM

To isolate specific gene expressed in human fetal liver tissue and find out genes with important biological functions.

METHODS

mRNA obtained from 4-months human fetus liver tissue was used as tester, and mRNA obtained from adult liver tissue was used as driver, and representational difference analysis (RDA) was performed. The subtracted final product was subcloned into the pGEM-T easy vector, after transformation, bacterial colonies were randomly picked, and 54 plasmid clones with inserts were purified and sequenced. The homology search of genes was performed by online-based BLAST program through the nonredundant and EST database at Nation Center of Biotechnology Information (NCBI), the expression pattern of novel gene was further verified by competitive PCR.

RESULTS

Marker with alpha-globin gene family, its expression frequency in subtractive cDNA pool is 7 times than non-subtractive cDNA library, and the pool contains many genes closely relative with liver growth. These show that RDA is an effective method to isolate gene differential expression. Through sequencing some clones, we get two sequences not reported before.

CONCLUSION

The library is a useful means to study genes expressed specially in fetal liver.

The involvement of calcium mobilization in the calcium-activated potassium currents activated by hyposmotic swelling in gastric antral circular myocytes of the guinea-pig

In our study of the effects of hyposmotic swelling on the Ca(2+)-activated potassium currents [I(K(Ca))] and its mechanism, we employed the whole-cell patch clamp technique using the gastric antral circular myocytes of the guinea-pig. Hyposmotic swelling efficiently increased I(K(Ca)), and the extent of changes in I(K(Ca)) was sharply dependent on the osmolarity of the perfusion solutions. When the calcium-free solution (EGTA 10 microM added in calcium-free solution) was superfused, I(K(Ca)) was not increased by the hyposmotic swelling. Gadolinium (Gd(3+)) 100 nM, a blocker of the stretch-activated nonselective cation channel, blocked the activation of I(K(Ca)) induced by hyposmotic swelling, but nicardipine 5 microM (the L-type calcium channel blocker) did not. Heparin 3 mg/ml, a potent inhibitor of inositol triphosphate receptor (InsP(3)R), did not inhibit the response, and caffeine 1 mM (the agonist for calcium-induced calcium release [CICR]) imitated the effect of hyposmotic swelling. Ryanodine (15 microM), markedly inhibited the effect. These results suggest that hyposmotic swelling activates I(K(Ca)), and the activation is associated with CICR, which is triggered by extracellular calcium influx through the stretch-activated channel (SA channel).

Preparation and characterization of hCG-loaded polylactide or poly(lactide-co-glycolide) microspheres using a modified water-in-oil-in-water (w/o/w) emulsion solvent evaporation technique

A modified w/o/w emulsion solvent evaporation technique was adopted to prepare human Chorionic Gonadotropin (hCG)-loaded polylactide (PLA) or poly(lactide-co-glycolide) (PLGA) microspheres. The effects of preparative parameters, such as stirring rate, polymer MW and concentration, and the composition of both the inner aqueous phase and oil phase etc., on hCG entrapment efficiency and microsphere characteristics were investigated. It was found that by adding 20% glycerol into the inner aqueous phase and 40% acetone into the oil phase, smooth microspheres approximately 1 microm in diameter could be produced with high hCG entrapment efficiency (>90%). In vitro release test showed a burst release of hCG from PLGA (75:25) microspheres, followed by sustained release of 55% hCG over 2 months. The initial hCG burst from PLGA microspheres increased with the glycerol concentration in the inner aqueous phase, but decreased to a low value (ca. 20%) with the addition of acetone into the oil phase, which could be attributed to the associated changes in surface morphology of the microspheres. In vivo experiments demonstrated that a single shot of hCG-loaded PLGA microspheres could produce a comparable antibody response with the inoculation of free hCG four times.

[Study on the expression of pig zona pellucida-3 beta excluding N-terminus signal peptide and C-terminus transmembrance-like domain in Escherichia coli]

Pig oocytes are surrounded by an acellular translucent envelope-zona pellucida(pZP), which is comprised of three biochemically and immunologically distinct glycoproteins(pZP1, pZP3 alpha and pZP3 beta). Due to the cross-reactivity of anti-pZP3 beta antibodies with human ZP in vitro, pZP3 beta has been considered as potential one of immunogens for developing human contraceptive vaccine. In order to express pZP3 beta directly in E. coli; we amplified the core fragment of pZP3 beta cDNA by PCR that was deleted 5'- and 3'-terminal sequences of coding for signal peptide and transmembrane-like domain. The DNA sequenced EcoRI and SalI restriced core fragment was cloned in a frame downstream of PRPL promoter in the pBV221 vector. SDS-PAGE analysis showed that pZP3 beta protein was expressed especially in E. coli after thermal induction, which the expression band displayed the molecular weight of about 38 kD matching with its deduced molecular weight(36.5 kD). In addition, the specially expressed protein band on SDS-PAGE gel showed specific immunological reaction with anti-pig ZP IgGs of rabbit in Western blot.

[Isolation of regulation genes related with liver regeneration by representational difference analysis]

mRNA isolated from 2/3 partially hepatectomied rats was used as a tester for representational difference analysis (RDA). The subtracted tester cDNA was cloned into a T vector and a rat regeneration liver specific EST pool was constructed, which contained about 30000 independent clones. A sequence analysis of 52 clones randomly picked up from this pool indicated that the liver regeneration specific sequences were enriched, and the results of RNA blots revealed some novel genes in association with liver regeneration.

Effects of nitroprusside, 3-morpholino-sydnonimine, and spermine on calcium-sensitive potassium currents in gastric antral circular myocytes of guinea pig

AIM

To determine the effect of nitric oxide (NO) on calcium-activated potassium currents in antral circular myocytes of the guinea pig stomach.

METHODS

The whole-cell patch-clamp techniques were used, and the cells were isolated by collagenase. Sodium nitroprusside (SNP), spermine, and 3-morpholino-sydnonimine (SIN-1) were used as nitric oxide donors.

RESULTS

Outward potassium currents were remarkably inhibited by tetraethylammonium (TEA) 1 mmol.L-1. Charybdotoxin 200 nmol.L-1, a specific inhibitor of KCa channel, also greatly inhibited IK(Ca). NO donors remarkably increased IK(Ca) in guinea pig gastric antral circular myocytes with perforated patch-clamp techniques but not conventional whole-cell patch-clamp techniques. Spermine 100 mumol.L-1 increased IK(Ca) by 14% +/- 10% (at 60 mV, P < 0.01), SIN-1 200 mumol.L-1 increased IK(Ca) by 19% +/- 14% (at 60 mV, P < 0.01), and SNP 100 mumol.L-1 increased IK(Ca) by 24% +/- 13% (at 60 mV, P < 0.01) respectively. SIN-1- and SNP-induced increase of IK(Ca) was blocked by methylene blue 1 mumol.L-1.

CONCLUSION

NO increases calcium-activated potassium currents in gastric antral circular myocytes of guinea pig, and the effect of NO on IK(Ca) may be mediated by cyclic GMP.

Effect of nitric oxide on electric and mechanical activities of gastric antral circular muscles in guinea pigs

AIM

To study the effect of exogenous nitric oxide (NO) on electric and mechanical activities of gastric antral circular muscle in guinea pigs in vitro.

METHODS

Mechanical and electric activities of gastric antral circular muscle in guinea pigs were recorded simultaneously.

RESULTS

Sodium nitroprusside (SNP, 0.5 mumol.L-1), an NO donor, inhibited the frequency and amplitude of fast wave and spontaneous contraction of the strips (P < 0.01). SNP-induced inhibition was not blocked by tetrodotoxin, atropine, phentolamine, and propranolol (P > 0.05), but diminished by methylene blue (P < 0.01) and oxyhemoglobin (P < 0.01).

CONCLUSION

Exogenous NO inhibits gastric antral myoelectric and mechanical activities in guinea pigs. The inhibitions are produced by NO acting on extracellular membrane and enhancing the level of cGMP.

Effects of different kinds of stretch on voltage-dependent calcium current in antrial circular smooth muscle cells of the guinea-pig

In order to elucidate the effect of membrane stretch on ionic currents, we employed the whole-cell patch-clamp technique to investigate the effects of different kinds of stretch on voltage-dependent calcium currents in antrial circular smooth muscle cells of the guinea-pig. The membrane stretch induced by superfusing the smooth muscle cells with hyposmotic bath solution enhanced voltage-operated calcium current and activated inward holding current. The increase in calcium current occurred within 1 minute of superfusion and the sustained inward holding current was slowly activated after prominent cell swelling. Voltage-dependent calcium currents (Ica) were significantly increased by membrane stretch which was induced by cell swelling and cell inflation, but was not affected by direct longitudinal stretch (110 130%) using two electrodes. The results suggest that the cell membrane stretch can increase voltage-dependent calcium channel activity and the effect of stretch on calcium channels was related to the membrane tension and/or the direction of membrane stretch.

Volume-sensitive chloride current activated by hyposmotic swelling in antral gastric myocytes of the guinea-pig

The characteristics of volume-sensitive chloride current (ICl) induced by osmotic cell swelling were studied using the whole-cell patch-clamp technique and cell diameters of antral circular guinea-pig myocytes were simultaneously measured under isosmotic and hyposmotic conditions by using a video image analysis system. At -60 mV, osmotic cell swelling (200 mosmol/l) activated a sustained inward current. Instantaneous current/voltage (I-V) relations obtained by step voltage pulses showed an outward rectification. At potentials above +40 mV, the current exhibited time-dependent decay. The outward current amplitude was decreased and the reversal potential was shifted to more positive potentials by replacement of external Cl- with gluconate-, while the current amplitude and the I/V relation were not affected by replacing extracellular Na+ with N-methyl-D-glucamine. The anion permeability sequence of the swelling-induced current was I- (1.80) > Br- (1.31) > Cl- (1) > F- (0.85) > gluconate- (0.18). The ICl was effectively inhibited by the Cl- channel blockers, 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS, 100 microM), and niflumic acid (10 microM). DIDS suppressed outward current more effectively than inward current. Also, the ICl was dose-dependently inhibited by arachidonic acid, an unsaturated fatty acid and also inhibited by other unsaturated fatty acids (linoleic acid and oleic acid) but not by stearic acid, a saturated fatty acid. The inhibitory effect of arachidonic acid on ICl was not prevented by indomethacin, a cyclo-oxygenase inhibitor and chelerythrine, a protein kinase C inhibitor. Under whole-cell patch-clamp conditions, the cell diameter was continuously measured using video image analysis, which reflects the change in cell volume. A hyposmotic-stimulation-induced increase of cell diameter was followed by ICl activation. In intact single gastric myocytes, relatively severe hyposmotic (176 mosmol/l) superfusing solution increased the cell diameter and the pretreatment with DIDS or with niflumic acid significantly potentiated the above effect of hyposmotic superfusion. These results suggest that volume-sensitive outwardly rectifying chloride current (ICl) is present in guinea-pig gastric myocyte and the ICl may play a role in smooth muscle cell volume regulation.

Role of actin microfilament in osmotic stretch-induced increase of voltage-operated calcium channel current in guinea-pig gastric myocytes

Using the whole-cell patch clamp technique, the role of actin microfilament in hyposmotic increase of voltage-operated calcium channel current (IBa) was studied in guinea-pig gastric myocytes. Hyposmotic superfusate (212 mOsm) increased peak IBa amplitude by 32.7 +/- 6.5%; when cytochalasin-D (Cyt-D, 20 microM), an actin cytoskeleton disruptor, was used, an increase of only 9.7 +/- 3.1% was seen. IBa response to osmotic stress was potentiated (45.1 +/- 4.1% increase) by 20 microM phalloidin, an actin microfilament stabilizer. However, colchicine (100 microM), an microtubule cytoskeleton disruptor, had no effect on either IBa or its response to hyposmotic solution. Phalloidin also induced a rightward shift of the I/V relationship of IBa, while Cyt-D itself had no effect. These results suggest that actin cytoskeleton may mediate hyposmotic stretch-induced IBa increase in gastric smooth muscle.

Effect of stretch on calcium channel currents recorded from the antral circular myocytes of guinea-pig stomach

The effect of membrane stretch on voltage-activated Ba2+ current (IBa) was studied in antral circular myocytes of guinea-pig using the whole- cell patch-clamp technique. The changes in cell volume were elicited by superfusing the myocytes with anisosmotic solutions. Hyposmotic superfusate (202 mosmol/l) induced cell swelling and increased peak values of IBa at 0 mV (from -406.6 +/- 45.5 pA to -547.5 +/- 65.6 pA, mean +/- SEM, n = 8) and hyperosmotic superfusate (350 mosmol/l) induced cell shrinkage and decreased peak values of IBa at 0 mV (to -269.5 +/- 39.1 pA, n = 8). Such changes were reversible and the extent of change was dependent on the osmolarity of superfusate. The values of normalized IBa at 0 mV were 1.43 +/- 0.04, 1.30 +/- 0.06, 1.23 +/- 0.04, 1.19 +/- 0.04, 1 and 0. 68 +/- 0.06 at 202, 220, 245, 267, 290 and 350 mosmol/l, respectively (n = 8). IBa was almost completely blocked by nicardipine (5 microM) under hyposmotic conditions. The values of steady-state half-inactivation voltage (-37.7 +/- 3.3 and -36.5 +/- 2.6 mV, under control and hyposmotic conditions, respectively) or the half-activation voltage (-13.6 +/- 2.3 and -13.9 +/- 1.9 mV) of IBa were not significantly changed (P > 0.05, n = 6). Cell membrane capacitance was slightly increased from 50.00 +/- 2.86 pF to 50.22 +/- 2.82 pF by a hyposmotic superfusate (P < 0.05, n = 6). It is suggested that cell swelling increases voltage-operated L-type calcium channel current and that such a property is related to the response of gastric smooth muscle to mechanical stimuli.

Effects of purinergic agonists on mechanical and electrical activities of gastric smooth muscle of guinea-pig

The effects of purinergic agonists on the mechanical and electrical activity of antral circular muscle of guinea-pig stomach were investigated. ATP potentiated the mechanical contraction without any change in membrane potential. To characterize the purinoceptors involved, effects of ATP analogues, especially P2X or P2Y receptor agonists, were studied. 2-MethylthioATP (2-MeSATP), a P2Y agonist, showed the same effects as that of ATP. On the other hand, a P2X agonists, alpha, beta-methyleneATP (alpha, beta-MeATP) incuced relaxation with hyperpolarization. At the holding potential of 0 mV, spontaneous transient outward currents (STOCs) were recorded in whole-cell mode. Externally applied ATP revealed transient increase of STOCs. Considering that STOCs reflect the changes of internal Ca2+, these results might be explained by the transient increase of internal Ca2+ release from internal Ca2+ store. From these results, it is concluded that there are at least two types of purinoceptors in guinea-pig stomach, and contractile response via P2Y-purinoceptor might be related to the elevation of internal Ca2+ released from internal Ca2+ store.

Morphological, physiological and enzymatic characteristics of cephalosporin acylase-producing Arthrobacter strain 45-8A

A bacterial strain producing cephalosporin acylases was isolated from soil. The morphological and physiological properties of this strain suggest that it belongs to the genus Arthrobacter, and the isolate was therefore designated Arthrobacter strain 45-8A. Substrate specificity of the enzyme was examined. The enzyme can convert both cephalosporin acid to 7-aminocephalosporanic acid. An interesting feature of the acylases is their temperature-dependent regulation. Activity of acylases was detected in strain 45-8A grown at temperature below 30 degrees C, but was not observed at higher temperature. Arthrobacter strain 45-8A did not exhibit beta-lactamase activity, even though its resistance to cephalosporin C was very strong (> 2000 micrograms/ml). This is quite beneficial for its application in the manufacture of 7-aminocephalosporanic acid.

[Protective effect of indomethacin on alloxan-induced diabetes in rat]

Changes of concentration of serum glucose, insulin and glucagon induced by preadministration of indomethacin were observed in normal rats and diabetic rats induced by alloxan. The results demonstrated that the level of serum glucose in diabetic rats was lowered significantly after preadministration of indomethacin (10 mg/kg) dose-dependently. After preadministration of 5, 10, 15 mg/kg of indomethacin the level of serum glucose 48 h after injecting alloxan was decreased from the control value of 591.5 +/- 38.2 mg% to 559.1 +/- 53.2, 436 +/- 16.6 and 266.6 +/- 29.9 mg% respectively. The concentration of serum insulin was increased from the control 10.5 +/- 2.7 microU/ml to 31.9 +/- 7.0 microU/ml and glucagon from 550.0 +/- 27.0 pg/ml to 303.1 +/- 22.9 pg/ml after preadministration of 10 mg/kg indomethacin. Histologic observation showed that alloxan induced beta cell lesion in pancreatic islet could indeed be prevented by indomethacin to a significant extent.