Apoptotic gene expression by human periodontal ligament cells following cyclic stretch

BACKGROUND AND OBJECTIVE

Periodontal ligament cells play an important role in maintaining homeostasis of periodontal tissue upon mechanical force loading caused by mastication or orthodontic force. Previous studies revealed force-driven periodontal ligament cell death via apoptosis, but the force-sensing genes assigned to the apoptotic pathway have not been fully characterized. The present study aimed to identify force-sensing genes implicated in the apoptotic pathway in periodontal ligament cells.

MATERIAL AND METHODS

Human periodontal ligament cells were exposed to 20% stretch strain for 6 or 24 h, and the differential expression of 84 genes implicated in the apoptotic pathway were quantified by real-time PCR array technology.

RESULTS

Ten and 11 genes showed upregulated expression after 6 and 24 h stretches, respectively, and there were two downregulated genes in response to both 6 and 24 h stretches. These genes included those encoding the tumor necrosis factor ligand family (TNFSF8), tumor necrosis factor receptor family (FAS, TNFRSF10B, TNFRSF11B, TNFRSF25 and CD27), the Bcl-2 family (BAG3, BAK1, BCL2L11 and BCLAF1), the caspase family (CASP5 and CASP7), the inhibitor of apoptosis proteins family (BIRC3, BIRC6 and NAIP), the caspase recruitment domain family (RIPK2 and PYCARD) and the death domain family (DAPK1), as well as an oncogene (BRAF).

CONCLUSION

This study identified several force-sensing genes implicated in the apoptotic pathway in periodontal ligament cells and should facilitate future studies on force-driven apoptosis by providing putative target genes.

Transzygomatic approach to the tentorial incisura: surgical anatomy

A simple transzygomatic approach to the middle fossa centered on the inferior retraction of the temporal muscle after transection of the zygomatic arch is described. This approach allows a very low basal exposure of the middle and temporal fossa, minimizing the amount of temporal lobe retraction needed to approach intradural and extradural lesion in this location. This approach is simple, easily performed, does not require extensive skull base removal, and still offers excellent visualization of the middle fossa and of the region of the tentorial incisura.

A combined intradural presigmoid-transtransversarium-transcondylar approach to the whole clivus and anterior craniospinal region: anatomic study

Surgical exposure of the clivus is difficult because of its proximity to vital neurovascular structures. The anatomic bases of a new surgical approach to this area are discussed. A supra-auricular skin incision is extended toward the posterior border of the sternocleidomastoid muscle. The vertebral artery is exposed from C2 to the occiput unroofing the foramen transversarium of C1. The bone removal consists of a posterior temporal craniotomy, a suboccipital craniectomy, including mastoidectomy with sigmoid sinus unroofing, removal of the lateral margin of the foramen magnum, of the medial third of the occipital condyle, and retrolabyrinthine petrous drilling. Posterior retraction of the vertebral artery facilitates occipital condyle drilling. Intradural exposure of the petroclival region is achieved by L-shaped cutting of the dura with the long branch placed infratentorially anterior to the sigmoid sinus. Intradural exposure of the craniospinal/upper cervical areas is achieved by cutting of the dura medial to the distal sigmoid sinus and by longitudinal cutting of the dura anterior to the vertebral artery. This approach allows multiple ports of entry to the clivus with full control of the vertebrobasilar system, and of the dural sinuses, and is anatomically suited for controlled removal of tumors located in these areas. This approach, or segments of it, has been used successfully in the treatment of large neoplasms of the craniovertebral junction.

High prevalence of bla(CTX-M) extended-spectrum β-lactamase genes in Escherichia coli isolates from pets and emergence of CTX-M-64 in China

As a cause of community-acquired infections, extended-spectrum β-lactamase (ESBL)-producing Escherichia coli constitute an emerging public-health concern. Few data on the molecular epidemiology of ESBL-producing E. coli isolates from pets are available in China. Detection and characterization of ESBL genes (bla(CTX-M), bla(SHV) and bla(TEM)) was conducted among 240 E. coli isolates recovered from healthy and sick pets in South China from 2007 to 2008. The clonal relatedness of ESBL-producing E. coli isolates was assessed by pulsed field gel electrophoresis. ESBL-encoding genes were identified in 97 (40.4%) of the 240 isolates and 96 (40.0%) of them harbored CTX-M. The most common CTX-M types were CTX-M-14 (n = 45) and CTX-M-55 (n = 24). The recently reported CTX-M-64 was identified in three isolates. Isolates producing CTX-M-27, -15, -65, -24, -3 and -9 were also identified. Ten isolates carried two or three CTX-M types, with the combination of CTX-M-14 and CTX-M-55 being the most frequent (n = 6). ISEcp1 was identified in the upstream region of 93 out of the 107 bla(CTX-M) genes (86.9%). The sequence of the spacer region (45 bp) between ISEcp1 and the start codon of all bla(CTX-M-55) genes (except four) was identical to that of bla(CTX-M-64). No major clonal relatedness was observed among these CTX-M producers. It is suggested that the horizontal transfer of bla(CTX-M) genes, mediated by mobile elements, contributes to their dissemination among E. coli isolates from pets. Our finding of high prevalence of ESBL in E. coli of companion animal origin illustrates the importance of molecular surveillance in tracking CTX-M-producing E. coli strains in pets.

Giant anharmonic phonon scattering in PbTe

Understanding the microscopic processes affecting the bulk thermal conductivity is crucial to develop more efficient thermoelectric materials. PbTe is currently one of the leading thermoelectric materials, largely thanks to its low thermal conductivity. However, the origin of this low thermal conductivity in a simple rocksalt structure has so far been elusive. Using a combination of inelastic neutron scattering measurements and first-principles computations of the phonons, we identify a strong anharmonic coupling between the ferroelectric transverse optic mode and the longitudinal acoustic modes in PbTe. This interaction extends over a large portion of reciprocal space, and directly affects the heat-carrying longitudinal acoustic phonons. The longitudinal acoustic-transverse optic anharmonic coupling is likely to play a central role in explaining the low thermal conductivity of PbTe. The present results provide a microscopic picture of why many good thermoelectric materials are found near a lattice instability of the ferroelectric type.

ZD6474, a small molecule tyrosine kinase inhibitor, potentiates the anti-tumor and anti-metastasis effects of radiation for human nasopharyngeal carcinoma

PURPOSE

To investigate the capacity for ZD6474, a small molecule tyrosine kinase inhibitor, to enhance anti-tumor and anti-metastasis effects of radiation on human nasopharyngeal carcinoma (NPC).

EXPERIMENTAL DESIGN

NPC cell lines and xenograft models were evaluated following treatment with ZD6474 and radiation alone and in combination compared with untreated control mice.

RESULTS

Treatment with ZD6474 enhanced the anti-proliferative effect of radiation on NPC cell lines as detected by cell proliferation and apoptosis assays. ZD6474 also induced a significant increase in the radiosensitivity of NPC cells, with radiation enhancement ratios (RERs) ranging from 1.2 to 1.6. Despite the cytotoxicity exhibited by NPC cells following radiotherapy, the invasion and migration of NPC cells was found to be unaffected. In contrast, treatment with ZD6474 strongly inhibited the invasion and migration of NPC cells. When the administration of radiation and ZD6474 was investigated in vitro, the ability of ZD6474 to inhibit activation of the pro-survival signaling pathways induced by radiation was demonstrated. In vivo, ZD6474 significantly enhanced the anti-metastasis effects of radiation, while treatment with radiation and ZD6474 was found to be well tolerated and resulted in a strong inhibition of tumor growth.

CONCLUSIONS

Our results suggest the combination of radiation and ZD6474 represents a promising strategy for the treatment of human NPC.

Single-primer PCR correction: a strategy for false-positive exclusion

Polymerase chain reaction (PCR) technology plays an important role in molecular biology research, but false-positive and nonspecific PCR amplification have plagued many researchers. Currently, research on the optimization of the PCR system focuses on double-primer-based PCR products. This research has shown that PCR amplification based on single-primer binding to the DNA template is an important contributing factor to obtaining false-positive results, fragment impurity, and nonspecific fragment amplification, when the PCR conditions are highly restricted during PCR-based target gene cloning, detection of transgenic plants, simple-sequence repeat marker-assisted selection, and mRNA differential display. Here, we compared single- and double-primer amplification and proposed "single-primer PCR correction"; improvements in PCR that eliminate interference caused by single-primer-based nonspecific PCR amplification were demonstrated and the precision and success rates of experiments were increased. Although for some kinds of experiments, the improvement effect of single-primer PCR correction was variable, the precision and success rate could be elevated at 12-50% in our experiment by this way.

Liraglutide provides similar glycaemic control as glimepiride (both in combination with metformin) and reduces body weight and systolic blood pressure in Asian population with type 2 diabetes from China, South Korea and India: a 16-week, randomized, double-blind, active control trial(*)

AIM

To assess and compare the efficacy and safety of liraglutide with those of glimepiride, both in combination with metformin for the treatment of type 2 diabetes in Asian population from China, South Korea and India.

METHODS

A 16-week, randomized, double-blind, double-dummy, four-arm, active control trial was carried out. In total, 929 subjects with type 2 diabetes with a mean (±s.d.) age of 53.3 ± 9.5 years, HbA₁(c) of 8.6 ± 1.0% and body weight of 68.1 ± 11.7 kg were randomized (liraglutide 0.6, 1.2 or 1.8 mg once daily or glimepiride 4 mg once daily all in combination with metformin: 1 : 1 : 1 : 1). One subject withdrew immediately after randomization and before exposure.

RESULTS

HbA₁(c) was significantly reduced in all groups compared with baseline. Treatment with liraglutide 1.2 and 1.8 mg was non-inferior to glimepiride (mean HbA₁(c) reduction: 1.36% points, 1.45% points and 1.39% points, respectively). No significant difference was shown in the percentage of subjects reaching American Diabetes Association HbA₁(c) target <7% or American Association of Clinical Endocrinologists target ≤6.5% between liraglutide 1.2 and 1.8 mg and glimepiride. Liraglutide was associated with a 1.8-2.4 kg mean weight reduction, compared with a 0.1 kg mean weight gain with glimepiride. Liraglutide led to a significantly greater reduction in systolic blood pressure (SBP) compared with glimepiride. Two subjects in the glimepiride group reported major hypoglycaemia while none in the liraglutide groups. Liraglutide was associated with about 10-fold lower incidence of minor hypoglycaemia than glimepiride. Gastrointestinal disorders were the most common adverse events (AEs) for liraglutide, but were transient and resulted in few withdrawals.

CONCLUSIONS

In Asian subjects with type 2 diabetes, once-daily liraglutide led to improvement in glycaemic control similar to that with glimepiride but with less frequent major and minor hypoglycaemia. Liraglutide also induced a significant weight loss and reduced SBP and was generally well tolerated. The most frequently reported AE was transient nausea. The effect of liraglutide in this Asian population is comparable to the effects seen in Caucasian, African American and Hispanic populations in global liraglutide phase 3 trials.

Problems with and a system to eliminate single-primer PCR product contamination in simple sequence repeat molecular marker-assisted selection in soybean

Polymerase chain reaction (PCR) provides a foundation for simple sequence repeat molecular marker-assisted selection (SSR MAS) in soybean. This PCR system and its various conditions have been optimized by many researchers. However, current research on the optimization of the PCR system focuses on double-primer PCR products. We compared single- and double-SSR primer PCR products from 50 soybean samples and found that the use of single-PCR primers in the reaction system can lead to amplified fragments of portions of the SSR primers in the PCR process, resulting in both false-positives and fragment impurity of double-primer PCR amplification, inconvenient for subsequent analysis. We used "single-primer PCR correction" to eliminate interference caused by single-primer nonspecific PCR amplification and improve PCR quality. Using this method, the precision and success rates of SSR MAS in soybean can be increased.

Plant height affects Fusarium crown rot severity in wheat

Effects of plant height on Fusarium crown rot (FCR) disease severity were investigated using 12 pairs of near-isogenic lines (NILs) for six different reduced height (Rht) genes in wheat. The dwarf isolines all gave better FCR resistance when compared with their respective tall counterparts, although the Rht genes involved in these NILs are located on several different chromosomes. Treating plants with exogenous gibberellin increased FCR severity as well as seedling lengths in all of the isolines tested. Analysis of the expression of several defense genes with known correlation with resistance to FCR pathogens between the Rht isolines following FCR inoculation indicated that the better resistance of the dwarf isolines was not due to enhanced defense gene induction. These results suggested that the difference in FCR severity between the tall and dwarf isolines is likely due to their height difference per se or to some physiological and structural consequences of reduced height. Thus, caution should be taken when considering to exploit any FCR locus located near a height gene.

Obesity, insulin resistance and the prevalence of atopy and asthma in US adults

BACKGROUND

The roles of obesity and insulin resistance in asthma and atopy are not well understood. We investigated whether there is an association of obesity and insulin resistance with asthma and atopy prevalence in US adults.

METHODS

Data from the 2005-2006 National Health and Nutrition Examination Survey were analyzed by multivariate logistic regression, controlling for sex, age, ethnicity, income, and smoking status. Obesity was measured by body mass index (BMI) and waist circumference, and insulin resistance by the homeostasis model assessment. Asthma was defined by self-report of ever receiving a diagnosis and still having asthma currently, and atopy by any positive specific serum IgE responses to a panel of aeroallergens.

RESULTS

Neither obesity measure nor insulin resistance was associated with atopy. Obesity was positively associated with asthma overall (odds ratio [OR] for obese vs normal BMI = 2.28, 95% CI: 1.76, 2.96; OR for obese vs normal waist circumference = 1.75; 95% CI: 1.22, 2.51) but insulin resistance was not (OR = 1.26; 95% CI: 0.80, 1.98). Obesity was also associated with nonatopic asthma (OR for obese vs normal BMI = 2.5; 95% CI: 1.2, 5.2; OR for obese vs normal waist circumference = 2.07, 95% CI: 1.21, 3.54), while obese BMI was also associated with atopic asthma (OR = 2.04, 95% CI: 1.37, 3.03). Obesity remained independently associated with all asthma outcomes after controlling for insulin resistance.

CONCLUSION

Obesity was independently associated with asthma, and atopic and nonatopic asthma, after controlling for insulin resistance and socio-demographic factors. There was no evidence that insulin resistance was associated with atopy or asthma.