Influence of pH and ionic strength on the physicochemical and structural properties of soybean β-conglycinin subunits in aqueous dispersions

Understanding the impact of pH and ionic strength on the physicochemical and structural properties of soy proteins at subunit level is essential for design and fabrication of many plant-based foods. In this study, soybean β-conglycinin and its subunit fractions αα' and β were dispersed in solutions with different pH values (3.7, 7.6, and 9.0) at low (5 mM NaCl) and high (400 mM NaCl) ionic strengths, respectively. The solubility, rheology, particle size, zeta potential, microstructure, secondary structure, and tertiary structure of the different dispersions were analyzed using a range of analytical methods. The β-conglycinin, αα'- and β-subunits aggregated near the isoelectric point (pH 3.7). Increasing the ionic strength led to the assembly of more homogeneous units. An increase in ionic strength at pH 7.6 and pH 9.0 led to electrostatic screening, which promoted dissociation of the aggregates. The β-subunit showed a greater sensitivity to pH and ionic strength than the αα'-subunits. Based on the evidence from a range of analytical methods, the highly hydrophilic extension region of the αα'-subunits played an important role in determining the stability of the β-conglycinin dispersions under different environmental conditions. Moreover, the N-linked glycans appeared to impact the conformation and aggregation state of the β-conglycinin.

An In Vitro Comparison of the Digestibility and Gastrointestinal Fate of Scallops and Plant-Based Scallop Analogs

Concerns exist regarding the negative environmental impact and health risks associated with ocean fishing and aquaculture, such as stock depletion, pollution, biodiversity loss, and toxin presence. To address these concerns, plant-based seafood analogs are being developed. Our previous study successfully created plant-based scallop analogs using pea proteins and citrus pectin, resembling real scallops in appearance and texture. This study focuses on comparing the digestive fate of these analogs to real scallops, as it can impact their nutritional properties. Using an in vitro digestion model (INFOGEST), we simulated oral, gastric, and small intestinal conditions. The analysis revealed differences in the microstructure, physicochemical properties, and protein digestibility between the plant-based scallops and real scallops. The particle size and charge followed the following similar trends for both types of scallops: the particle size decreased from the mouth to the stomach to the small intestine; the particles were negative in the mouth, positive in the stomach, and negative in the small intestine. The protein digestibility of the plant-based scallops was considerably lower than that of real scallops. For instance, around 18.8% and 61.4% of protein was digested in the stomach and small intestine phases for the real scallop (80.2% total digestion), whereas around 8.7% and 47.7% of the protein was digested for the plant-based scallop (56.4% total digestion). The lower digestibility of the plant-based scallops may have been due to differences in the protein structure, the presence of dietary fibers (pectin), or antinutritional factors in the plant proteins. These findings are crucial for developing more sustainable next-generation plant-based seafood analogs.

Excess serum Na level in rats administered with high doses of (-)-epigallocatechin gallate-casein nanoparticles prepared with sodium caseinate

(-)-Epigallocatechin gallate (EGCG)-incorporated casein nanoparticles benefit from excellent antioxidant, anti-inflammatory and anti-cancer activities due to their synergistic efficiency, but few studies have evaluated their safety. In this study, the EGCG-casein nanoparticles (EGCG-NPs) formulated using caseinate by ultrasonic treatment were evaluated for their subacute toxicity. The subacute toxicity test of EGCG-NPs through 28-day oral administration in rats did not exhibit adverse effect, with a no-observed-adverse-effect level (NOAEL) of at least 5.0 g per kg body weight (BW) per day, which was equivalent to 500 mg per kg BW EGCG per day. However, the serum Na level in females and males treated with 10.0 g per kg BW EGCG-NPs increased significantly as compared to the control rats (P < 0.05). Similar indications appeared in rats treated with 10.0 g per kg BW pure casein nanoparticles without EGCG, which indicated that high doses of caseinate nanoparticles result in an excess serum Na level. Therefore, we should consider the safety of the nanoparticle formulation of caseinate when it is used as a loading nutrient and a functional substance in foods.

Enhanced antibacterial activity of eugenol-entrapped casein nanoparticles amended with lysozyme against gram-positive pathogens

This study aimed to investigate the antibacterial efficiency and synergistic mechanisms of novel formulated eugenol-casein-lysozyme nanoparticles (ECL-NPs) against gram-positive bacteria. We obtained optimized ECL-NPs 151.9 nm in size and with an entrapment efficiency of 92.2%. ECL-NPs exhibited a satisfactory slow-release pattern, excellent storage stability (for 180 days at 4 °C), and freeze-drying stability. The synergy of low-dose lysozyme significantly enhanced the inhibitory efficiency of eugenol-casein nanoparticles against Staphylococcus aureus and Bacillus sp. by 5.83-fold and 5.53-fold, respectively; this resulted in a much lower minimum inhibitory concentration (3.75-fold and 4.16-fold) and minimum bacterial concentration (2.92-fold and 1.70-fold) values. Scanning electron microscopy clearly demonstrated that the entire cell morphological structure was broken into pieces after exposure to ECL-NPs. Furthermore, 100% microbial inhibition was observed in fresh fruits treated with ECL-NPs for 15 days. These findings suggest that ECL-NPs have an excellent potential for use in food industry against gram-positive bacteria.

A novel cholesterol-free mayonnaise made from Pickering emulsion stabilized by apple pomace particles

Yolk-based mayonnaise is widely used to enhance the flavor of daily food. In view of health concerns on dietary cholesterol, novel mayonnaises (NMs) were made from Pickering emulsions stabilized by apple pomace particles using micro-jet (MJ-NM), ultrasonic (US-NM), and high-speed-shear homogenizer (HSS-NM), respectively. NMs and commercial mayonnaise (CM) were comparatively investigated in appearance, droplet size, rheological, tribological, and stability properties. NMs presented almost identical appearances to CM except for color. The droplets' size in NMs were larger than CM. Both NMs and CM demonstrated shear-thinning behavior and solid-like properties. Among mayonnaises, MJ-NM was demonstrated the most rapid thixotropy recovery with its storage modulus recovered within 51 s. Although both NMs and CM were of mixed tribology nature, NMs presented lower oral lubricity. Upon 210-day storage, both NMs and CM exhibited excellent stabilities without any oil-water separation occurred. Overall, the Pickering emulsions are promising and health alternatives for traditional mayonnaise.

Inactivation of Penicillium italicum on kumquat via plasma-activated water and its effects on quality attributes

Plasma-activated water (PAW) has good liquidity and uniformity and may be a promising candidate to inactivate Penicillium italicum and maintain the quality attributes of kumquat. In this study, the effect of plasma-activated water (PAW) on the viability of Penicillium italicum on kumquat and quality attributes of PAW-treated kumquats were then systematically investigated to elucidate the correlation between PAW and kumquat quality attributes. The effects of PAW on fruit decay, microbial loads, and firmness of postharvest kumquats during the 6-week storage were also investigated. The results showed that the viability of Penicillium italicum was notably inhibited by PAW on kumquats. Moreover, PAW did not significantly change the surface color of kumquats. No significant reductions in ascorbic acid, total flavonoid, and carotenoids were observed in kumquats after the PAW treatment. Results from nitrate and nitrite residue analyses showed that PAW did not leave serious nitrate and nitrite residues after treatment. The decay analysis results demonstrated that PAW has the potential to control kumquat decay and fungal contamination as well as maintain the firmness of postharvest kumquats throughout 6-week storage. Transmit electron microscope observation confirmed that PAW could cause the surface sculpturing in the skin cell wall of kumquat. The information obtained from this research may provide insight into the utilization of PAW to fight against fungal infection during the storage of citrus fruit.

Superior anti-infective potential of eugenol-casein nanoparticles combined with polyethylene glycol against Colletotrichum musae infections

The aim of this study was to improve the stability of eugenol-casein nanoparticles (EL-CS-NPs) through polyethylene glycol (PEG) modification. The results show that modifying the EL-CS-NPs with PEG after loading with eugenol (EL) gives PEG-EL-CS-NPs, with increased stability. The NPs modified with higher-molecular-weight PEG showed better stability. A CS/PEG ratio of 200 : 1 (w/w) yielded the NPs with the best stability. A PEG20 K-EL-CS-NP dispersion remained stable in cold storage for over one year, and also exhibited stronger inhibitory effects against Colletotrichum musae inoculated on bananas than an EL-CS-NP dispersion, since it showed more prolonged sustained release of EL than the EL-CS-NP dispersion. Lyophilized PEG20 K-EL-CS-NP powder showed better effectiveness against mold on bread than lyophilized EL-CS-NPs powder. Using PEG to modify CS-NPs shows potential for improving the stability of CS-NPs loaded with hydrophobic substances for delivery in the fields of food and agriculture.

Low-dose vardenafil potentiates the protective effect of (-)-epigallocatechin gallate on cardiomyocytes

The major polyphenol (-)-epigallocatechin gallate (EGCG) of green tea shows well-known health benefits such as potential anti-cancer, anti-oxidation and ameliorating cardiovascular disease. This work aims to improve the bioactivity of EGCG on H9C2 cardiomyocytes by combination regimen of vardenafil and EGCG. The proliferative rates were significantly improved by 18.74%, 10.77% and 29.17% after 48 h with EGCG, vardenafil, and the combination of EGCG and low-dose vardenafil treatments, respectively. The treatments also increased the expression of the nitric oxide synthase (eNOS), and acutely stimulate production of vasodilators nitric oxide (NO) from 17.33μmol/L to 19.75, 20.87 and 24.47μmol/L in H9C2 cells. We further demonstrated that vardenafil also remarkably promoted EGCG to counteract H₂O₂-induced apoptotic damage in H9C2 by strengthening antioxidant defense systems and suppressing myocardial apoptosis. These results suggest that EGCG and low-dose vardenafil in combination may be a promising regimen to help prevent cardiovascular diseases.

Quality of Split-Mouth Trials in Dentistry: 1998, 2008, and 2018

The objectives of this study were to assess the reporting quality and methodological quality of split-mouth trials (SMTs) published during the past 2 decades and to determine whether there has been an improvement in their quality over time. We searched the MEDLINE database via PubMed to identify SMTs published in 1998, 2008, and 2018. For each included SMT, we used the CONsolidated Standards Of Reporting Trials (CONSORT) 2010 guideline, CONSORT for within-person trial (WPT) extension, and a new 3-item checklist to assess its trial reporting quality (TRQ), WPT-specific reporting quality (WRQ), and SMT-specific methodological quality (SMQ), respectively. Multivariable generalized linear models were performed to analyze the quality of SMTs over time, adjusting for potential confounding factors. A total of 119 SMTs were included. The mean overall score for the TRQ (score range, 0 to 32), WRQ (0 to 15), and SMQ (0 to 3) was 15.77 (SD 4.51), 6.06 (2.06), and 1.12 (0.70), respectively. The primary outcome was clearly defined in only 28 SMTs (23.5%), and only 27 (22.7%) presented a replicable sample size calculation. Only 45 SMTs (37.8%) provided the rationale for using a split-mouth design. The correlation between body sites was reported in only 5 studies (4.2%) for sample size calculation and 4 studies (3.4%) for statistical results. Only 2 studies (1.7%) performed an appropriate sample size calculation, and 46 (38.7%) chose appropriate statistical methods, both accounting for the correlation among treatment groups and the clustering/multiplicity of measurements within an individual. Results of regression analyses suggested that the TRQ of SMTs improved significantly with time ( P < 0.001), while there was no evidence of improvement in WRQ or SMQ. Both the reporting quality and methodological quality of SMTs still have much room for improvement. Concerted efforts are needed to improve the execution and reporting of SMTs.

Micronized apple pomace as a novel emulsifier for food O/W Pickering emulsion

In order to develop natural, food-grade particles as emulsifiers, wet-milled has been conducted to obtain apple pomace particles in varying sizes. Structural characteristics, physicochemical properties and Pickering emulsifying potential of the particle in different sizes were investigated. Particle size of apple pomace was gradually reduced from 12.9 μm to 550 nm during 8 h milling. With the decrease of particles size, the morphology became less angular. Meanwhile, some insoluble dietary fibers transformed into soluble ones, and the wettability tended to be hydrophilic, therefore, the water and oil holding capacities and free-radical-scavenging capacities increased. The properties of Pickering emulsions stabilized by wet-milled apple pomace particles in different sizes were then investigated. The decrease of particle size resulted in the size reduction of emulsion droplets, and gave rise to enhance gel-like properties and antioxidative activities of emulsions. The results demonstrated promising prospect of wet-milled apple pomace particles as emulsifiers in food industry.

Structural Modification of Nanomicelles through Phosphatidylcholine: The Enhanced Drug-Loading Capacity and Anticancer Activity of Celecoxib-Casein Nanoparticles for the Intravenous Delivery of Celecoxib

This study aims to stabilize loaded celecoxib (CX) by modifying the structure of casein nanoparticles through phosphatidylcholine. The results show that Egg yolk phosphatidylcholine PC_98T (PC) significantly increased the stability of CX-PC-casein nanoparticles (NPs) (192.6 nm) from 5 min (CX-β-casein-NPs) to 2.5 h at 37 °C. In addition, the resuspended freeze-dried NPs (202.4 nm) remained stable for 2.5 h. Scanning electron microscopy indicated that PC may block the micropore structures in nanoparticles by ultrasonic treatment and hence improve the physicochemical stability of CX-PC-casein-NPs. The stability of the NPs was positively correlated with their inhibiting ability for human malignant melanoma A375 cells. The structural modification of CX-PC-casein-NPs resulted in an increased intracellular uptake of CX by 2.4 times than that of the unmodified ones. The pharmacokinetic study showed that the Area Under Curve (AUC) of the CX-PC-casein-NPs was 2.9-fold higher in rats than that of the original casein nanoparticles. When CX-PC-casein-NPs were intravenously administrated to mice implanted with A375 tumors (CX dose = 16 mg/kg bodyweight), the tumor inhibition rate reached 56.2%, which was comparable to that of paclitaxel (57.3%) at a dose of 4 mg/kg bodyweight. Our results confirm that the structural modification of CX-PC-casein-NPs can effectively prolong the remaining time of specific drugs, and may provide a potential strategy for cancer treatment.

Prevalence and Risk Factors Governing the Loss of Muscle Function in Elderly Sarcopenia Patients: A longitudinal Study in China with 4 Years of Follow-Up

OBJECTIVES

Data regarding the occurrence of risk factors that promote the loss of muscle mass, strength and function in sarcopenia patients in elderly Chinese patients are sparse. Here, we investigated the alterations in muscle mass, function and strength in those with sarcopenia over a 4-year period. We further evaluated the risk factors leading to a loss of grip strength, gait speed and skeletal muscle mass index in sarcopenia patients.

DESIGN

A face-to-face cross-sectional survey.

SETTING AND PARTICIPANTS

The study population consisted of 560 Chinese aged over 59 years.

MEASUREMENTS

Study recordings took places over a four-year period from 2014. Muscle mass was assessed through bioelectrical impedance analysis (BIA) performed on an Inbody720, Biospace. Hand-grip strength and 6 m walking speed were used as measurements of muscle strength and function. Sarcopenia was diagnosed using the Asian Working Group for Sarcopenia criteria (AWGS).

RESULTS

In total, 474 of the elderly residents completed the follow-up. The rates of decreased ASMI, grip strength, and gait speed in the sarcopenia patients increased over the 4-year period. Following multivariate analysis, age was identified as the main risk factor for all the observed decrease, gender was specifically related to the loss of ASMI, stroke was a risk factor for gait speed and sarcopenia. A high BMI was a risk factor for a low gait speed but was protective for a loss of skeletal muscle mass and sarcopenia.

CONCLUSIONS

Age leads to a decline in muscle strength and function. In elderly Chinese patients with sarcopenia, the rates of reduced grip strength, gait-speed and sarcopenia increased. A high BMI was protective against the decline in muscle mass and sarcopenia, but represented a risk factor for low gait speed. Stoke was identified to cause a loss of gait speed in sarcopenia patients.

Orange Fragrance with Sustained-Release Properties Prepared by Nanoethosomal Encapsulation of Natural Orange Essential Oil

There is an upsurge of interest in improving the stability and prolong the scent holding time of fragrances in cosmetic industry. In this study, to encapsulate the orange essential oils (OEO), nanoethosomes were constructed with optimized proportions of ethanol, water, soybean phosphatidylcholine (SPC), Tween 80, and palm oil sucrose esters (PSE). The controlled-release behavior of nanoethosomes was then studied concerning physicochemical stability, microstructure, and olfactory sensation. The sustained-release effectiveness of the nanoethosomal fragrances was influenced by particle size and OEO amount of specific formula. Herein, there was a positive correlation between particle size and sustained-release effectiveness. In particular, the mean diameter of nanoethosomal orange fragrances (nano-OFs)-prepared by EO-ethanol-water-SPC-Tween 80-PSE (3-7:25:72-68:2:1.0:0.1) and 3%, 5%, and 7% OEO-was 68.6±3.6, 79.5±4.5 and 87.3±6.9 nm, respectively. The results of olfactory sensation and GC-MS analysis showed that these fragrances could sustainedly release the aromatic compounds to yield satisfactory smell longer than that of the conventional orange fragrance. Furthermore, the nano-OF made of 5% EO yield a satisfactory smell more than 3 h, which was 3 times of that of the conventional orange fragrance. This fragrance was stable when stored at 4 °C (>1 year) and 25 °C (>10 months). The knowledge gained from this study will be helpful to develop nanoethosomal fragrances or perfumes for commercial use.

[Effect of NLRP3 mediated pyroptosis in myocardial cells undergoing hypoxia/deoxygenation injury]

Objective: To investigate the effect of NACHT-LRR-PYD- containing proteins 3 (NLRP3) mediated pyroptosis in myocardial cells undergoing hypoxia/deoxygenation (H/R) injury. Methods: In order to observe whether H/R-treatment could cause pyroptosis, H9c2 cells were divided into 2 groups randomly using the lottery method: control group(without H/R-treatment) and H/R group (in which the H9c2 cells were underwent H/R-treatment). In order to clarify the role of pyroptosis in H/R-injury, H9c2 cells were divided into 4 groups randomly using the lottery method: control group(in which the H9c2 cells were cultivated with normal medium); YVAD group(in which the H9c2 cells were pretreated with z-Val-Ala-Asp(Ome)-fluoromethylketone (Z-YVAD-FMK) 20 μm for 4 hours, then replaced with normal medium); H/R group(H9c2 cells underwent H/R-treatment); YVAD+H/R group (in which the H9c2 cells were pretreated with 20 μm Z-YVAD-FMK for 4 hours before H/R-treatment). To determine whether H/R-induced cell pyroptosis is associated with NLRP3, H9c2 cells were divided into 4 groups randomly using the lottery method: control group (in which cells were transfected with a control nonspecific siRNA); si-NLRP3 group (in which cells were transfected with NLRP3-targeting siRNA); H/R group(in which cells were transfected with a control nonspecific siRNA before H/R-treatment); si-NLRP3+H/R group(in which the H9c2 cells were transfected with NLRP3-targeting siRNA before H/R-treatment). Pore formation on cell membrane was detected by propidium iodide (PI) staining. Cell viability was detected by CCK8 reagent. The protein expression of Caspase-1, interleukin-1β (IL-1β) and NLRP3 was detected by Western blot. Results: (1) The positive rate of PI staining ((26.46±5.15)% vs. (1.69±0.73)%,P<0.01), expression of NLRP3 (0.57±0.16 vs. 0.23±0.06,P<0.01), expression of Caspase-1 (1.07±0.13 vs. 0.37±0.08,P<0.01), and expression of IL-1β (0.38±0.08 vs. 0.16±0.05,P<0.01) were significantly higher in H/R group than in control group. (2)The cell vitality was significantly higher in YVAD+H/R group than in H/R group ((87.31±9.05)% vs. (73.30±7.19)%, P<0.05).The positive rate of PI staining was significantly decreased in YVAD+H/R group than in H/R group ((18.12±4.36)% vs. (26.45±4.60)%, P<0.05). The expression of Caspase-1 (0.72±0.12 vs. 1.07±0.15, P<0.05) and IL-1β(0.29±0.07 vs. 0.39±0.06, P<0.05) were significantly lower in YVAD+H/R group than in H/R group. (3) The cell vitality was significantly increased in si-NLRP3+H/R group than in H/R group ((85.46±7.71)% vs. (72.41±5.53)%, P<0.05). The positive rate of PI staining was significantly lower in si-NLRP3+H/R group than in H/R group ((18.22±4.20)% vs. (26.73±3.26)%, P<0.05). The expression of Caspase-1(0.87±0.07 vs. 1.15±0.15, P<0.05) and IL-1β(0.41±0.07 vs. 0.58±0.10, P<0.05) were significantly decreased in si-NLRP3+H/R group than in H/R group. Conclusion: NLRP3 mediated pyroptosis is involved in H/R injury of myocardial cells.

Enhanced Antiarthritic Efficacy by Nanoparticles of (-)-Epigallocatechin Gallate-Glucosamine-Casein

This work aims to improve the antiarthritic activity of (-)-epigallocatechin gallate (EGCG) and glucosamine (GA) through fabrication and optimization of casein protein nanoparticles (EGC-NPs). Optimized EGC-NPs were obtained with a EGCG/GA/casein ratio of 1:2:8 (w/w/w). The EGC-NPs gave a mean size of 186 ± 3.5 nm and an entrapment efficiency of 86.8 ± 2.7%, and they exhibited a greater inhibitory activity against human fibroblast-like synoviocytes-osteoarthritis cells and human fibroblast-like synoviocytes-rheumatoid arthritis cells compared with that of the EGCG-GA mixture by 33.5% and 20.8%, respectively. Freeze-dried EGC-NPs stored at 25 °C during 12 months showed high dispersion stability. Moreover, the redispersion of the freeze-dried EGC-NPs produced almost no significant changes in their physicochemical properties and bioactivity. Rat experiments demonstrated that the antiarthritis effect of the EGC-NPs was significantly higher than that of EGCG-GA mixture, as assessed through an analysis of anti-inflammatory efficacy, radiographic images and histopathological assessments of paw joints, and immunohistochemical changes in serum cytokines. The enchanced antiarthritic activity in vivo was consistent with that in vitro. The EGC-NPs demonstrate potential as a food supplement for the treatment of arthritis.

Systemic disruption of the homeostasis of transfer RNA isopentenyltransferase causes growth and development abnormalities in Bombyx mori

Isopentenylation at A37 (i⁶ A37) of some transfer RNAs (tRNAs) plays a vital role in regulating the efficiency and fidelity of protein synthesis. However, whether insects, which are well known for their highly efficient protein synthesis machinery, employ this regulatory mechanism remains uninvestigated. In the current study, a candidate tRNA isopentenyltransferase (IPT) gene with three alternative splicing isoforms (BmIPT1-BmIPT3) was identified in Bombyx mori (silkworm). Only BmIPT1 could complement a yeast mutant lacking tRNA IPT. Phylogenetic analysis showed that silkworm tRNA IPT is conserved in the Lepidoptera. BmIPT was expressed in all B. mori tissues and organs that were investigated, but was expressed at a significantly higher level in silk glands of the fourth instar compared to the first day of the fifth instar. Interestingly, BmIPT was expressed at a significantly higher level in the domesticated silkworm, B. mori, than in wild Bombyx mandarina in multiple tissues and organs. Knock-down of BmIPT by RNA interference caused severe abnormalities in silk spinning and metamorphosis. Constitutive overexpression of BmIPT1 using a cytoplasmic actin 4 promoter in B. mori raised its messenger RNA level more than sixfold compared with nontransgenic insects and led to significant decreases in the body weight and cocoon shell ratio. Together, these results confirm the first functional tRNA IPT in insects and show that a suitable expression level of tRNA IPT is vital for silk spinning, normal growth, and metamorphosis. Thus, i⁶ A modification at position A37 in tRNA probably plays an important role in B. mori protein synthesis.

Enhancement in Antibacterial Activities of Eugenol-Entrapped Ethosome Nanoparticles via Strengthening Its Permeability and Sustained Release

The antibacterial efficiency and synergistic mechanisms of novel formulated eugenol entrapped ethosome nanoparticles (ELG-NPs) against fruit anthracnose were investigated. The results showed that concentrations of eugenol and ethanol significantly influenced the particle size and entrapment efficiency of nanoethosome, and the particle size significantly influenced the antibacterial effect. Superior ELG-NPs with optimized process (0.5% eugenol, 2% lecithin, and 30% ethanol) were obtained with a size of 44.21 nm and entrapment efficiency of 82%. ELG-NPs exhibited an antibacterial activity (>93%) against fruit pathogens that was greater than that of free eugenol and showed 100% inhibition of the anthracnose incidence in postharvest loquat after 6 d. The permeability study, first visualized in banana cortex with fluorescent indicators, demonstrated that eugenol delivered to the interior with ELG-NPs was 6-fold higher than that of free eugenol. ELG-NPs showed a satisfactory slow-release and prolonged antibacterial action. This work provides a promising strategy for disease controls in agricultural, food, cosmetic, and medical areas.

Does audiovisual distraction reduce dental anxiety in children under local anesthesia? A systematic review and meta-analysis

OBJECTIVES

To perform a systematic review and meta-analysis on the effects of audiovisual distraction on reducing dental anxiety in children during dental treatment under local anesthesia.

METHODS

The authors identified eligible reports published through August 2017 by searching PubMed, EMBASE, and Cochrane Central Register of Controlled Trials. Clinical trials that reported the effects of audiovisual distraction on children's physiological measures, self-reports, and behavior rating scales during dental treatment met the minimum inclusion requirements. The authors extracted data and performed a meta-analysis of appropriate articles.

RESULTS

Nine eligible trials were included and qualitatively analyzed; some of these trials were also quantitatively analyzed. Among the physiological measures, heart rate or pulse rate was significantly lower (p = .01) in children subjected to audiovisual distraction during dental treatment under local anesthesia than in those who were not; a significant difference in oxygen saturation was not observed. The majority of the studies using self-reports and behavior rating scales suggested that audiovisual distraction was beneficial in reducing anxiety perception and improving children's cooperation during dental treatment.

CONCLUSION

The audiovisual distraction approach effectively reduces dental anxiety among children. Therefore, we suggest the use of audiovisual distraction when children need dental treatment under local anesthesia.

Metabolites from the co-culture of nigranoic acid and Umbelopsis dimorpha SWUKD3.1410, an endophytic fungus from Kadsura angustifolia

The ability of the endophytic fungus Umbelopsis dimorpha SWUKD3.1410 to transform the triterpene nigranoic acid (3, 4-secocycloarta-4(28), 24-(Z)-diene-3, 26-dioic acid; 1) was investigated. Co-culture of nigranoic acid with U. dimorpha SWUKD3.1410 yielded six major products, including a new triterpene (2) and 5 known compounds (3-7). Their structures were identified by the extensive 1D, 2D NMR and HR-ESI-MS Data analysis, and by comparison with those reported data. Among them, 2-4 were transformed from nigranoic acid (1), while 5-7 were derived from the culture medium stimulated by the substrate. On the basis of the structures of 2-4, it was proposed that the transformative process probably involved isomerase and hydroxylase, in which the former was rare in fungi. Additionally, all the compounds (1-7) were evaluated for their cytotoxic activity. As a result, compounds 1, 3-5 exhibited weak cytotoxicity against the tested cell lines, while others showed no cytotoxicity.

Roles of nicotinic acetylcholine receptors in stem cell survival/apoptosis, proliferation and differentiation

The potential of stem cells in regenerative medicine, developmental biology, and drug discovery has been well documented. For example, stem cells have the extraordinary ability of self-renewal, and also give rise to many specialized cells. It is clear that stem cell technology has revolutionized our understanding of modern biology and medicine and provided new insights into the mechanisms controlling basic cell biology and various diseases. Nicotinic acetylcholine receptors (nAChRs) are prototypical members of the ligand-gated ion channel super family of neurotransmitter receptors that play many critical roles in brain and body function. It has been demonstrated that in addition to mediation of classical excitatory neurotransmission at some loci and modulation of release of neurotransmitters in some cases, nAChRs also play important roles in influencing synaptic architecture and plasticity as well as neuronal survival/death. Recently, emerging lines of evidence have suggested that nAChRs express on stem cells, where they likely mediate crucial effects of cholinergic signaling on stem cell survival/apoptosis, proliferation, differentiation and maturation. In this review, we summarize current development in cholinergic modulations of stem cell survival/apoptosis, proliferation and differentiation in order to evaluate the impact of nAChRs in stem cell biology and pathology.

Synergy between Kaposi's sarcoma-associated herpesvirus (KSHV) vIL-6 and HIV-1 Nef protein in promotion of angiogenesis and oncogenesis: role of the AKT signaling pathway

Kaposi's sarcoma-associated herpesvirus (KSHV) is the cause of Kaposi's sarcoma (KS), which is the most common AIDS-associated malignancy. KS is characterized by neovascularization and spindle cell proliferation. The interaction between HIV-1 and KSHV has a central role in promoting the aggressive manifestations of KS in AIDS patients; however, the pathogenesis underlying AIDS-related KS (AIDS-KS) remains unknown. Herein, we examined the potential of HIV-1 negative factor (Nef) to impact KSHV viral interleukin-6 (vIL-6)-induced angiogenesis and tumorigenesis. In vitro experiments showed that exogenous Nef penetrated vIL-6-expressing endothelial cells. Both internalized and ectopic expression of Nef in endothelial cells and fibroblasts synergized with vIL-6 to promote vascular tube formation and cell proliferation. Using a chicken chorioallantoic membrane (CAM) model, we demonstrated that Nef synergistically promotes vIL-6-induced angiogenesis and tumorigenesis. Animal experiments further showed that Nef facilitates vIL-6-induced angiogenesis and tumor formation in athymic nu/nu mice. Mechanistic studies indicated that Nef synergizes with vIL-6 to enhance angiogenesis and tumorigenesis by activating the AKT pathway in the CAM model, as well as nude mice. LY294002, a specific inhibitor of phosphatidylinositol-3-kinase (PI3K), significantly impaired the ability of Nef to promote vIL-6-induced tumorigenesis in an allograft model of nude mice. Our data provide first-line evidence that Nef may contribute to the pathogenesis underlying AIDS-KS in synergy with vIL-6. These novel findings also suggest that targeting the PI3K/AKT signal may be a potentially effective therapeutic approach in AIDS-KS patients.

In situ synthesis and characterization of GaN nanorods through thermal decomposition of pre-grown GaN films

Herein we describe a thermal treatment route to synthesize gallium nitride (GaN) nanorods. In this method, GaN nanorods were synthesized by thermal treatment of GaN films at a temperature of 800 °C. The morphology and structure of GaN nanorods were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that GaN nanorods have a hexagonal wurtzite structure with diameters ranging from 30 to 50 nm. Additionally, GaN nanoplates are also founded in the products. The growth process of GaN nanostructures was investigated and a thermal decomposition mechanism was proposed. Our method provides a cost-effective route to fabricate GaN nanorods, which will benefit the fabrication of one-dimensional nanomaterials and device applications.

Identification of B cell epitopes at the C-terminus of latency-associated nuclear protein of the kaposi's sarcoma-associated herpesvirus

The latency-associated nuclear antigen (LANA) of Kaposi's sarcoma-associated herpesvirus (KSHV) plays a key role in the induction of cell transformation, maintenance of viral episome, and modulation of immune response in human. To identify the presence of B cell epitopes within C-terminus of LANA and to characterize the monoclonal antibodies (MAbs) against this protein, we expressed the C-terminal region at aa 794-1000 of LANA (pLANA-C) in Escherichia coli as a fusion protein. KSHV-positive human sera were able to recognize the recombinant LANA-C in the Western blot analysis and ELISA. Mapping of antigenic epitopes of pLANA-C by KSHV-positive human sera revealed two B cell antigenic epitopes located at aa 846-854 and aa 794-822. The MAb 3F11 recognized a region between at aa 840 to 846 of LANA and exhibited a strong and specific binding to both pLANA-C and native viral LANA. These findings showed that pLANA-C and MAb 3F11 could be used for the detection of KSHV antibodies in human sera and for the advanced study of biological functions of LANA.

Screening of upper digestive tract cancer with dilute hydrochloric acid and alcohol in a Chinese high-risk population--a follow-up study of 12 years

This is a 12-year follow-up study on screening with a mixture of 2% hydrochloric acid and 18% alcohol for upper digestive tract cancer in a Chinese high-risk population. A public screening for upper digestive tract cancer was conducted from November 1979 to May 1984 by giving a mixture of 2% hydrochloric acid and 18% alcohol to 7280 subjects in high-risk population in Yaocun village, Linxian County, Henan province. The subjects were given 15 ml of this mixture in the morning or at noon before lunch when fasting. Five minutes later, irritative reactions (retrosternal discomfort, warmth, pain or pyrosis) was felt in subjects suffering from oesophageal cancer, oesophagitis, gastritis, mucosal dysplasia or ulcer (positive group). Those with normal oesophageal or gastric mucosa felt nothing (negative group). The overall positive rate was 23.2% (1689/7280). In oesophageal or gastric cancer subjects, the positive rate of these symptoms was 88.7%. In subjects with mucosal dysplasia, it was 71.2%. A total of 26 upper digestive tract cancer patients were found. As a result of 12 years' follow-up, 271 persons with upper digestive tract cancer among the 1689 positive group subjects have been discovered, giving an annual morbidity rate of 1.34%. Among the 5591 negative group subjects, 136 persons have been found to suffer from this cancer, giving an annual morbidity rate of 0.2%. This illustrated that the annual morbidity rate of upper digestive tract cancer in the positive group was 6.65 times of that of the negative group ( <0.0001). In conclusion, screening of upper digestive tract cancer with dilute hydrochloric acid in alcohol is simple, safe, non-traumatic, effective and readily acceptable in a high-risk area in China. It may be feasible in other parts of the world, especially the developing countries.

[A limonoid from the Chinese drug dong-feng-jie (Atalantia buxifolia)]

A new limonoid was isolated from the ethanol extract of dried roots and stems of Atalantia buxifolia (Poir) Oliv.. Based on chemical properties and spectral analysis, including 1H- and 13CNMR, DEPT, MS, IR and UV spectra, its structure have been identified as: 6-deoxy-6 alpha-acetoxyatalantin acetate. This compound was isolated from this plant for the first time.

Improved efficacy of chemotherapy for glioblastoma by radiation-induced opening of blood-brain barrier: clinical results

PURPOSE

To improve the efficacy of chemotherapy for glioblastoma through the radiation-induced opening of the blood-brain barrier (BBB).

METHODS AND MATERIALS

In two previous articles, we have described the results of brain scanning using technetium 99m-labeled somatostatin and the measurement of methotrexate (MTX) concentrations in blood and cerebrospinal fluid (CSF) after i.v. injection. We discovered that the BBB and blood-cerebrospinal fluid barrier opened to a certain extent after 20- to 40-Gy irradiation, thus increasing the degree to which MTX permeated the brain tissue. On the basis of these findings, we retrospectively analyzed the outcome in 56 patients with glioblastoma given either chemotherapy (CCNU) after 20- to 40-Gy irradiation (28 patients) or radiation therapy alone (28 patients).

RESULTS

The 1-, 3-, and 5-year survival rates were 57.14%, 22.50%, and 15.00% in the combined-therapy group and 17.86%, 7.14%, and 3.57% in the radiotherapy alone group, respectively. The respective median survival times were 29.11 +/- 6.99 and 9.86 +/- 3.45 months (p < 0.001), which represented a statistically significant difference.

CONCLUSION

Our study further confirms that opening of the BBB induced by irradiation with 20-40 Gy may optimize the effects of intracranial chemotherapy.

Spatial alterations of Kv channels expression and K(+) currents in post-MI remodeled rat heart

OBJECTIVE

The hypothesis being tested in the present study is that increased anisotropic properties occurs in the remodeled post-infarction heart due to spatial alterations in Kv channels expression and K(+) currents of the remodeled myocardium.

METHODS

Three to 4 weeks post myocardial infarction (MI) in the rat, we measured the two components of the outward K(+) current, I(to-fast (f)) and I(to-slow(s)) in the epicardium (epi) and endocardium (endo) of noninfarcted remodeled left ventricle (LV) using patch clamp techniques. Alterations in mRNA and/or protein levels of potassium channel genes Kv1.4, Kv1.5, Kv2.1, Kv4.2 and Kv4.3 were measured in epi, midmyocardium (mid), and endo regions of LV and in the right ventricle (RV).

RESULTS

In sham operated rat heart, the density of I(to-f) was 2.3 times greater in epi compared to endo myocytes. In post-MI heart, the density of I(to-f) and I(to-s) decreased to a similar degree in LV epi and endo but the difference in I(to-f) density between epi and endo persisted. The mRNA and/or protein levels of Kv1.4, Kv2.1, Kv4.2 and Kv4.3 but not Kv1.5 decreased to a varying extent in different regions of LV but not in RV of post-MI heart.

CONCLUSIONS

Our results suggest that regional downregulation of Kv channels expression and density of K(+) currents can be a significant determinant of increased spatial electrophysiological heterogeneity and contribute to increased electrical instability of the post-MI heart.

Synchronization of separation and determination based on multichannel mode-filtered light detection with capillary electrophoresis

A novel method for the synchronization of separation and determination is described, in which a mode-filtered light detector is used as an online detector in capillary electrophoresis. An instrument is described which has been developed for this purpose. The round capillary used in conventional capillary electrophoresis is replaced by an annular column, which is constructed from a naked optical fibre inserted into a fused-silica capillary. In fact, the annular electrophoresis column itself forms part of the mode-filtered light sensor. Along the side of the annular column are several detection channels for gathering and transmitting the mode-filtered light to a charge-coupled device (CCD). Every channel provides information on the sample from the point at which it is located. Using capillary isotachophoresis incorporating the annular column, the analytes in a sample containing alanine (10.0 mM) and glycine (9.7 mM) were simultaneously separated and determined using multichannel mode-filtered light detection with a detection limit of 1.5 mM.

Capsaicin inhibits Jurkat T-cell activation by blocking calcium entry current I(CRAC)

Capacitative calcium entry (CCE) through stores-operated Ca2+ channels is an absolute requirement for normal activation of T lymphocytes. Organic blockers/inhibitors of the channel(s) that carry the inward Ca2+ current (I(CRAC)) responsible for CCE are few. Here we show that capsaicin, the pungent ingredient of hot chili pepper, blocks receptor-stimulated Ca2+ entry in Jurkat T cells. Indo-1 measurements of intracellular calcium show that capsaicin blocks CCE without affecting release of inositol-1,4,5-trisphosphate-sensitive internal Ca2+ stores with an IC50 of 32 microM. Block of Ca2+ entry by capsaicin is identical whether CCE is evoked by T-cell receptor (TCR) stimulation, heterologous muscarinic M1 receptor stimulation, or via thapsigargin depletion of internal Ca2+ stores. Patch-clamp experiments show that capsaicin rapidly and reversibly blocks I(CRAC) with an identical dose response as seen with indo-1 measurements. The major voltage-gated K+ channel in Jurkat cells, Kv1.3, is also blocked by capsaicin. Although Kv1.3 block may contribute to reducing CCE by changes in membrane potential, block of I(CRAC) is the primary mechanism by which capsaicin reduces CCE. Capsaicin analogs capsazepine and resiniferatoxin also produce inhibition of CCE via block of I(CRAC). Upon application of capsaicin to Jurkat cells in culture we observed an inhibition of interleukin-2 (IL-2) production in response to TCR stimulation. The dose dependence of capsaicin's reduction of IL-2 was comparable with its block of I(CRAC), thereby illustrating the functional relevance of capsaicin's block of lymphocyte CCE. Thus, capsaicin and its numerous analogs may have potential use as immunomodulatory drugs and should be further investigated in models of inflammation and T-cell activation.

Calcineurin inhibition ameliorates structural, contractile, and electrophysiologic consequences of postinfarction remodeling

INTRODUCTION

After myocardial infarction (MI), the heart undergoes an adaptive remodeling process characterized by hypertrophy of the noninfarcted myocardium. Calcineurin, a Ca2+-calmodulin-regulated phosphatase, has been shown to participate in hypertrophic signal transduction.

METHODS AND RESULTS

We investigated the effects of calcineurin inhibition by cyclosporin A on key structural, contractile, and electrophysiologic alterations of post-MI remodeling. Male Sprague-Dawley rats were divided into four groups: (1) sham-operated; (2) sham + cyclosporin A; (3) post-MI (left anterior descending coronary artery ligation); and (4) MI + cyclosporin A. Cyclosporin A (25 mg/kg/day) was initiated 2 days before surgery and continued for 30 days. Hypertrophy was evaluated by echocardiography and by changes in membrane capacitance of isolated myocytes from noninfarcted left ventricle (LV). The effects of cyclosporin A on hemodynamics and cardiac dimensions were investigated, and changes in diastolic function were correlated with changes in protein phosphatase 1 activity and the basal level of phosphorylated phospholamban. The effects of cyclosporin A on Kv4.2/Kv4.3 genes expression and transient outward K+ current (I(to)) density also were evaluated. One of 12 rats in the post-MI group and 2 of 12 rats in the post-MI + cyclosporin A group died within 48 hours after MI. There were no late deaths in either MI group. There was no evidence of heart failure (lung congestion and/or pleural effusion) in the two groups 4 weeks post-MI. Calcineurin phosphatase activity increased 1.9-fold in post-MI remodeled LV myocardium, and cyclosporin A administration resulted in an 86% decrease in activity. There were statistically significant decreases of LV end-diastolic pressure, LV end-diastolic diameter, and LV relative wall thickness in the post-MI + cyclosporin A group compared with the post-MI group. On the other hand, there was no significant difference in LV end-systolic diameter or peak rate of LV pressure increase between the two post-MI groups. Protein phosphatase 1 activity was elevated by 36% in the post-MI group compared with sham, and this correlated with a 79% decrease in basal level of p16-phospholamban. In the post-MI + cyclosporin A group, the increase in protein phosphatase 1 activity was much less (18% vs 36%; P < 0.05), and the decrease in basal level of p16-phospholamban was markedly ameliorated (20% vs 79%; P < 0.01). The decreases in mRNA levels of Kv4.2 and Kv4.3 and I(to) density in the LV of the post-MI + cyclosporin A group were significantly less compared with the post-MI group.

CONCLUSION

Our results show that calcineurin inhibition by cyclosporin A partially ameliorated post-MI remodeled hypertrophy, diastolic dysfunction, decrease in basal level of phosphorylated phospholamban, down-regulation of key K+ genes expression, and decrease of K+ current, with no adverse effects on systolic function or mortality in the first 4 weeks after MI.

Follicular dendritic cells: beyond the necessity of T-cell help

Follicular dendritic cells (FDCs) are potent accessory cells for B cells, but the molecular basis of their activity is not understood. Several important molecules involved in FDC-B-cell interactions are indicated by blocking the ligands and receptors on FDCs and/or B cells. The engagement of CD21 in the B-cell coreceptor complex by complement-derived CD21 ligand on FDCs delivers a crucial signal that dramatically augments the stimulation delivered by the binding of antigen to the B-cell receptor (BCR). The engagement of Fc gamma receptor IIB (FcgammaRIIB) by the Ig crystallizable fragment (Fc) in antigen-antibody complexes held on FDCs decreases the activation of immunoreceptor tyrosine-based inhibition motifs (ITIMs), mediated by the crosslinking of BCR and FcgammaRIIB. Thus, FDCs minimize a negative B-cell signal. In short, these ligand-receptor interactions help to signal to B cells and meet a requirement for B-cell stimulation that goes beyond the necessity of T-cell help.

Analysis of the cyclic nucleotide binding domain of the HERG potassium channel and interactions with KCNE2

Mutations in the cyclic nucleotide binding domain (CNBD) of the human ether-a-go-go-related gene (HERG) K+ channel are associated with LQT2, a form of hereditary Long QT syndrome (LQTS). Elevation of cAMP can modulate HERG K+ channels both by direct binding and indirect regulation through protein kinase A. To assess the physiological significance of cAMP binding to HERG, we introduced mutations to disrupt the cyclic nucleotide binding domain. Eight mutants including two naturally occurring LQT2 mutants V822M and R823W were constructed. Relative cAMP binding capacity was reduced or absent in CNBD mutants. Mutant homotetramers carry little or no K+ current despite normal protein abundance and surface expression. Co-expression of mutant and wild-type HERG resulted in currents with altered voltage dependence but without dominant current suppression. The data from co-expression of V822M and wild-type HERG best fit a model where one normal subunit within a tetramer allows nearly normal current expression. The presence of KCNE2, an accessory protein that associates with HERG, however, conferred a partially dominant current suppression by CNBD mutants. Thus KCNE2 plays a pivotal role in determining the phenotypic severity of some forms of LQT2, which suggests that the CNBD of HERG may be involved in its interaction with KCNE2.

Downregulation of K(+) channel genes expression in type I diabetic cardiomyopathy

Type I diabetic cardiomyopathy has consistently been shown to be associated with decrease of repolarising K(+) currents, but the mechanisms responsible for the decrease are not well defined. We investigated the streptozotocin (STZ) rat model of type I diabetes. We utilized RNase protection assay and Western blot analysis to investigate the message expression and protein density of key cardiac K(+) channel genes in the diabetic rat left ventricular (LV) myocytes. Our results show that message and protein density of Kv2.1, Kv4.2, and Kv4.3 are significantly decreased as early as 14 days following induction of type I diabetes in the rat. The results demonstrate, for the first time, that insulin-deficient type I diabetes is associated with early downregulation of the expression of key cardiac K(+) channel genes that could account for the depression of cardiac K(+) currents, I(to-f) and I(to-s). These represent the main electrophysiological abnormality in diabetic cardiomyopathy and is known to enhance the arrhythmogenecity of the diabetic heart. The findings also extend the extensive list of gene expression regulation by insulin.

[Elevation distribution of precipitation chemistry in middle/upper troposphere in summer, the northern slope of central Himalayas]

During 1997 summer, fresh snow samples were collected from four snowfall events from the elevation of 5800 to 7000 m in the Dasuopu Glacier region on the northern slope of Mt. Xixabangma (28 degrees 33'N, 85 degrees 44'E), in order to understand the elevation distribution of the middle/upper tropospheric components in the remote region. The correlation between SO4(2-), NO3-, Ca2+ and Mg2+ in precipitation differs with type of air mass, indicating the dominant sources of ions vary in short-term (e.g. several days) during summer low dust period. In general, with elevation increases, the concentrations of NO3-, Ca2+ and Mg2+ decreases, while SO4(2-) increases, which are influenced by the variation of dominant sources of ions.

[Therapeutic effect on glioblastoma of chemotherapy on the basis of brain irradiation]

OBJECTIVE

To study the efficacy of chemotherapy for glioblastoma on the basis of brain irradiation.

METHODS

It was previously reported that the permeability of the blood brain barrier (BBB) to methotrexate could be increased by brain irradiation. In this study, glioblastoma patients were divided into 2 groups, 28 patients in each group. On group of patients was treated with CCNU or BCNU after having given 20-40 Gy irradiation to the brain. The other group of patients received radiation treatment alone.

RESULTS

The 1-, 3-, and 5-year survival rate of the two groups of patients was 57.1%, 22.5%, 15.0% and 17.9%, 7.1%, 3.6%, respectively. The median survival time was 29.7 +/- 7.0 and 9.7 +/- 3.5 months, respectively (P < 0.001).

CONCLUSION

Increase in permeability of the BBB after 20-40 Gy brain irradiation may provide an optimal chance for intracranial chemotherapy of glioblastoma.

[Chemical characteristics of fresh snow in Mount Everest Region]

The chemistry of fresh snow samples collected in August and September, 1998 from Mount Everest was studied and compared with other fresh snow samples collected in different seasons in this region. The results indicated that major species in precipitation were very low in late summer in Mount Everest region and may be representative of the background of precipitation chemistry of remote regions in the wold. Chemical Characteristics of fresh snow in different seasons had distinct differences and they may reflect different moist source and climatic status. The precipitation in August and September was mainly come from Indian summer monsoon and in April and May it was influenced deeply by the dust of semi-arid and arid regions in central Asia. This indicates the precipitation in this region is climatic sensitively.

Alterations of sodium channel kinetics and gene expression in the postinfarction remodeled myocardium

INTRODUCTION

After a myocardial infarction (MI), the heart undergoes a remodeling process that includes hypertrophy of noninfarcted left ventricular myocytes. Alterations in the genetic expression, including reexpression of fetal isogene patterns, can result in electrophysiologic changes that contribute to the arrhythmogenicity of post-MI heart. The present study investigated possible alterations in gene expression of Na+ channel subtypes, as well as the kinetics of the Na+ current (I(Na)), in 3- to 4-week-old post-MI rat remodeled left ventricular myocardium.

METHODS AND RESULTS

Using a macropatch technique, we showed increased Na+ channel bursting activity during sustained depolarization in post-MI remodeled myocytes resulting in a large slow component of the I(Na) decay. A tetrodotoxin-sensitive current contributed 18% to the prolonged APD90 of isolated post-MI myocytes compared with 6% in control myocytes. Our molecular studies revealed that, in addition to the rat heart I (rH I) subtype, thought to be the predominant subtype that encodes a tetrodotoxin-resistant isoform, the brain subtypes NaCh I and NaCh Ia also are expressed in the rat myocytes. Post-MI remodeled myocardium showed increased expression of NaCh I protein with reversion of the NaCh Ia/NaCh I isoform ratio toward the fetal phenotype.

CONCLUSION

Our findings raise the possibility that the increase in the slow component of I(Na) in post-MI remodeled myocytes is secondary to the increased expression of NaCh I. Additional studies are required to address these questions and to characterize the functional role of the NaCh I subtypes in cardiac myocytes.

Follicular dendritic cell accessory activity crosses MHC and species barriers

Productive follicular dendritic cell (FDC)-B cell interactions appear to involve critical ligand-receptor interactions. Immune complexes (IC) on FDC activate complement and provide FDC with a complement-derived CD21 ligand (CD21L), which bind CD21, while antigen in the IC binds on the B cell-BCR. Further, FDC-FcgammaRIIB binds Fc regions of antibodies in IC and reduces coligation of BCR and FcgammaRIIB minimizing an inhibitor of B cell activation. Given that Fc receptors and complement receptors bind immunoglobulins and complement fragments of other species, we reasoned that FDC accessory activity should cross MHC and species barriers. This prediction was tested using memory lymphocytes from OVA-immune mice and TT-immune humans in combination with FDC from murine lymph nodes and human tonsils. Human and murine FDC converted IC into potent immunogens (specific antibody increased from background to thousands of ng / ml). MHC barriers did not restrict this activity and human FDC worked with murine lymphocytes and murine FDC worked with human lymphocytes. Furthermore, stimulation via MHC-dependent allogeneic or zenogeneic mechanisms did not promote antibody production by FDC. Polyclonal responses stimulated by lipopolysaccharide and pokeweed mitogen were also promoted (10 - 100-fold) and anti-CD21 blocked FDC activity. These results substantiate the hypothesis that FDC are necessary for strong recall responses and that FDC-CD21L is critical.

Structure of the FHA1 domain of yeast Rad53 and identification of binding sites for both FHA1 and its target protein Rad9

Forkhead-associated (FHA) domains have been shown to recognize both pThr and pTyr-peptides. The solution structures of the FHA2 domain of Rad53 from Saccharomyces cerevisiae, and its complex with a pTyr peptide, have been reported recently. We now report the solution structure of the other FHA domain of Rad53, FHA1 (residues 14-164), and identification of binding sites of FHA1 and its target protein Rad9. The FHA1 structure consists of 11 beta-strands, which form two large twisted anti-parallel beta-sheets folding into a beta-sandwich. Three short alpha-helices were also identified. The beta-strands are linked by several loops and turns. These structural features of free FHA1 are similar to those of free FHA2, but there are significant differences in the loops. Screening of a peptide library [XXX(pT)XXX] against FHA1 revealed an absolute requirement for Asp at the +3 position and a preference for Ala at the +2 position. These two criteria are met by a pThr motif (192)TEAD(195) in Rad9. Surface plasmon resonance analysis showed that a pThr peptide containing this motif, (188)SLEV(pT)EADATFVQ(200) from Rad9, binds to FHA1 with a K(d) value of 0.36 microM. Other peptides containing pTXXD sequences also bound to FHA1, but less tightly (K(d)=4-70 microM). These results suggest that Thr192 of Rad9 is the likely phosphorylation site recognized by the FHA1 domain of Rad53. The tight-binding peptide was then used to identify residues of FHA1 involved in the interaction with the pThr peptide. The results are compared with the interactions between the FHA2 domain and a pTyr peptide derived from Rad9 reported previously.