High expression of CD98 alters epithelial barrier functions to promote induction of airway allergy

BACKGROUND

Epithelial barrier dysfunction is critical in the induction of allergy; the aetiology is to be further understood. A recent report indicates that CD98 plays a role in the intestinal epithelial barrier dysfunction.

OBJECTIVES

This study aimed to investigate the role of overexpression of CD98 in the induction of nasal allergy.

METHODS

The nasal epithelium samples were collected from 30 patients with allergic rhinitis and 30 healthy subjects. The contents of CD98 and Staphylococcal enterotoxin B (SEB) in the nasal epithelium samples were evaluated by using Western blotting. The effect of SEB of inducing the expression of CD98 was evaluated with an airway epithelial cell line, the 16HBE14o cells. The epithelial barrier function was assessed with the indicators of transepithelial resistance (TER) and permeability to horseradish peroxidase (HRP). A mouse model was employed to evaluate the role of CD98 in the induction of nasal allergy.

RESULTS

High levels of CD98 and SEB were detected in the nasal epithelium of patients with allergic rhinitis. A positive correlation was identified between CD98 and SEB in nasal epithelium samples. Exposure to SEB could induce the overexpression of CD98 in RPMI 2650 and 16HBE14o cells. The overexpression of CD98 down-regulated TER and increased the permeability to HRP in 16HBE14o monolayers. Concurrent exposure to SEB and OVA induced nasal allergies in a mouse model that could be blocked by pre-treatment with anti-CD98 antibody.

CONCLUSIONS AND CLINICAL RELEVANCE

CD98 plays a critical role in compromising the airway epithelial barrier function that contributes to the induction of airway allergy.

Expression of human beta 1,4-galactosyltransferase in gynecological cancer cell lines

We examined the expression of beta 1,4-GT gene products in 11 gynecological cancer cell lines. A 4.7 kb mRNA and protein (54,000 Da and 57,000 Da) were detected by Northern blot and Western blot. Immunocytochemical staining revealed that beta 1,4-GT was localized in the Golgi or ER of tumor cells. An intense beta 1,4-GT mRNA signal was detected in ovarian and cervical cancer cells, whereas the level of beta 1,4-GT mRNA was very low in uterine endometrial cancer cells. We also confirmed that expression of beta 1,4-GT mRNA corresponded to expression of beta 1,4-GT protein. These results suggest that expression of the beta 1,4-GT gene products is higher in human cervical and ovarian cancer cells than in uterine endometrial cancer cells.

Platelet-activating factor and distinct chemokines are elevated in mucosal biopsies of erosive compared with non-erosive reflux disease patients and controls

BACKGROUND

A distinction between symptomatic non-erosive reflux disease (NERD) and erosive esophagitis (EE) patients is supported by the presence of inflammatory response in the mucosa of EE patients, leading to a damage of mucosal integrity. To explore the underlying mechanism of this difference, we assessed inflammatory mediators in mucosal biopsies from EE and NERD patients and compared them with controls.

METHODS

Nineteen NERD patients, 15 EE patients, and 16 healthy subjects underwent endoscopy after a 3-week washout from PPI or H(2) antagonists. Biopsies obtained from the distal esophagus were examined by quantitative real-time polymerase chain reaction (qPCR) and multiplex enzyme-linked immunosorbent assay for selected chemokines and lyso-PAF acetyltransferase (LysoPAF-AT), the enzyme responsible for production of platelet-activating factor (PAF).

KEY RESULTS

Expression of LysoPAF-AT and multiple chemokines was significantly increased in mucosal biopsies derived from EE patients, when compared with NERD patients and healthy controls. Upregulated chemokines included interleukin 8, eotaxin-1, -2, and -3, macrophage inflammatory protein-1α (MIP-1α), and monocyte chemoattractant protein-1 (MCP-1). LysoPAF-AT and the chemokine profile in NERD patients were comparable with healthy controls.

CONCLUSIONS & INFERENCES

Levels of selected cytokines and Lyso-PAF AT were significantly higher in the esophageal mucosa of EE patients compared with NERD and control patients. This difference may explain the distinct inflammatory response occurring in EE patients' mucosa. In contrast, as no significant differences existed between the levels of all mediators in NERD and control subjects, an inflammatory response does not appear to play a major role in the pathogenesis of the abnormalities found in NERD patients.

Platelet-activating factor and distinct chemokines are elevated in mucosal biopsies of erosive compared with non-erosive reflux disease patients and controls

BACKGROUND

A distinction between symptomatic non-erosive reflux disease (NERD) and erosive esophagitis (EE) patients is supported by the presence of inflammatory response in the mucosa of EE patients, leading to a damage of mucosal integrity. To explore the underlying mechanism of this difference, we assessed inflammatory mediators in mucosal biopsies from EE and NERD patients and compared them with controls.

METHODS

Nineteen NERD patients, 15 EE patients, and 16 healthy subjects underwent endoscopy after a 3-week washout from PPI or H(2) antagonists. Biopsies obtained from the distal esophagus were examined by quantitative real-time polymerase chain reaction (qPCR) and multiplex enzyme-linked immunosorbent assay for selected chemokines and lyso-PAF acetyltransferase (LysoPAF-AT), the enzyme responsible for production of platelet-activating factor (PAF).

KEY RESULTS

Expression of LysoPAF-AT and multiple chemokines was significantly increased in mucosal biopsies derived from EE patients, when compared with NERD patients and healthy controls. Upregulated chemokines included interleukin 8, eotaxin-1, -2, and -3, macrophage inflammatory protein-1α (MIP-1α), and monocyte chemoattractant protein-1 (MCP-1). LysoPAF-AT and the chemokine profile in NERD patients were comparable with healthy controls.

CONCLUSIONS & INFERENCES

Levels of selected cytokines and Lyso-PAF AT were significantly higher in the esophageal mucosa of EE patients compared with NERD and control patients. This difference may explain the distinct inflammatory response occurring in EE patients' mucosa. In contrast, as no significant differences existed between the levels of all mediators in NERD and control subjects, an inflammatory response does not appear to play a major role in the pathogenesis of the abnormalities found in NERD patients.

Comparison of the antiviral effects of entecavir and adefovir dipivoxil in chronic HBV infection: a randomized control trial

AIMS

The purpose of this study is to compare the antiviral efficacy of entecavir (ETV) and adefovir dipivoxil (ADV) at various time points during the treatment.

METHODS

A randomized, controlled, open-label study was designed to analyze the kinetics of HBeAg seroconversion, HBV DNA level, and liver and renal functions in 72 ETV-treated chronic hepatitis B (CHB) patients and 66 ADV-treated CHB patients. The data was collected every 12 weeks up to 96 weeks after drug administration.

RESULTS

The negative rate of HBeAg seroconversion was significantly increased at 24 weeks in ETV-treated patients, whereas in ADV-treated patients, these changes were not significant. The serum HBV DNA levels were significantly decreased from 24 weeks in both ETV- and ADV-treated patients. Other than ETV showing significantly decreased levels of HBV DNA at 24 weeks when compared with ADV, there was no difference in virological response between two treatments at any other time points. The serum alanine aminotransferase (ALT) and total bilirubin (TBIL) levels were significantly decreased 12 weeks after either ETV- or ADV-treated patients without differences between two treatments. The urea nitrogen levels were in normal range and there was no difference between two groups.

CONCLUSIONS

Our study suggested that both ETV and ADV could be used as monotherapy for nucleotide-naive patients, but ETV has displayed potential efficacy in HBeAg seroconversion.

Differential expression of two antifreeze proteins in the desert beetle Anatolica polita (Coleoptera: Tenebriondae): seasonal variation and environmental effects

Antifreeze proteins (AFPs) can inhibit and modify the growth of ice crystals. Two antifreeze protein genes, Apafp752 and Apafp914, were cloned from the desert beetle Anatolica polita (Coleoptera: Tenebriondae), and they shared 61.3 percent similarity at the amino acid level. Apafp752 also contained one variation in the most conserved TCT motif of beetle AFPs. Apafp752 and Apafp914 mRNAs had similar seasonal expression pattern. Both were stimulated by cold stress, but they expressed slightly differentially with Apafp752 being more sensitive to cold stress than Apafp914, and no more sensitive to desiccation stress than Apafp914. The thermal hysteresis activity (THA) in the beetle's hemolymph followed approximately the patterns of mRNA seasonal expression and expression upon environmental stress, with a time lag. Summer adults of the desert beetle also express mRNA of Apafp752 and Apafp914, and exhibit some hemolymph THA, suggesting other likely function of these proteins beyond antifreeze.

First Report of Broad bean wilt virus 2 in Echinacea purpurea in China

Field-grown Echinacea purpurea plants showing necrosis, leaf roll, yellow mosaic, and mosaic symptoms in leaves were collected in June 2010 in Huairou, Beijing, China. ELISAs of extracts of four samples showed that one sample with mosaic symptoms had a positive reaction with Broad bean wilt virus 2 (BBWV-2) monoclonal antibody provided by Professor X. P. Zhou (1). The monoclonal antibody recognized the 44.7 kD coat protein subunit of BBWV-2. We used Chenopodium quinoa as an assay species to isolate the virus by sap transmissions and to maintain the virus strain. Sap from infected C. quinoa, when inoculated onto indicator plant species, induced the following symptoms: C. quinoa: local lesions in inoculated leaves, systemic chlorotic mottle in upper leaves, deformation, and apical necrosis; C. amaranticolor: chlorotic local lesions, systemic mosaic and leaf distortion; Nicotiana benthamiana: systemic mosaic; Gomphrena globosa: local purple spots in inoculated leaves and systemic infection in upper leaves; Tetragonia expansa: local lesions, but no symptoms of systemic infection; Physalis floridana: systemic mosaic. No symptoms were observed on Capsicum annuum, Datura stramonium, N. glutinosa, or N. tabacum cv. White Burley. To confirm BBWV-2 infection, total RNAs extracted from infected C. quinoa leaves were reverse transcripted to cDNA using oligo-dT primer (T17V). The primer pair Fab5'R1F (5'-AAATATTAAAACAAACAGCTTTCGTT-3') and Fab5'R1R (5'-TTCAAAGCTCGTGCCATNTYATTKGC-3') for specific detection of the Fabavirus genus (2) was used for PCR analysis. The amplified fragment is between the 5'-terminal non-translatable region (NTR) and the beginning of the coding region of RNA1. Amplicons of approximately the expected size (~391 bp) were produced from the virus-infected C. quinoa and a BBWV-2 positive control (ATCC PV131, PV0537). Amplicons of approximately the expected size (~350 bp) were produced from the BBWV-1 positive control (ATCC PV132). However, no such amplicons were observed from healthy C. quinoa plants and water control. The 391-bp amplicons of RNA1 obtained from the infected C. quinoa were cloned and sequenced. Comparison with sequences of other BBWV-2 isolates showed that the isolate we obtained (No. JX070674) had approximately 99% nt identity (98% amino acid identity) with Chinese BBWV-2 isolate BC (No. FJ485686.1) (3). As an ornamental and medicinal plant, E. purpurea is widely cultivated in northern China. Up until now, Tomato ring spot virus, Tobacco rattle virus, Cucumber mosaic virus, and Tomato spotted wilt virus have been detected or isolated from E. purpurea in the world (4). To our knowledge, this is the first report of BBWV-2 infecting E. purpurea in China. BBWV-2-infected E. purpurea may have less secondary metabolites, which could influence the quality and therapeutic efficacy of this herbal medicine. References: (1) L. Qing et al. Acta Microbiologica Sinica 40:166, 2000. (2) R. M. Ferrer et al. J. Virol. Methods 144:156, 2007. (3) C. Sui et al. Plant Dis. 93:844, 2009. (4) B. Dikova. Bulgarian J. Agric. Sci. 17:306, 2011.

Efficacy and tolerability of vildagliptin as add-on therapy to metformin in Chinese patients with type 2 diabetes mellitus

AIM

To investigate the efficacy and tolerability of vildagliptin as add-on therapy to metformin in Chinese patients with type 2 diabetes mellitus (T2DM) inadequately controlled with metformin.

METHODS

This was a 24-week, randomized, double-blind, placebo-controlled study. Patients with T2DM (N = 438) with haemoglobin A1c (HbA1c) of 7.0-10.0% and fasting plasma glucose (FPG) <15 mmol/l (<270 mg/dl) were randomized (1 : 1 : 1) to vildagliptin 50 mg bid, vildagliptin 50 mg qd or placebo in addition to metformin.

RESULTS

The treatment groups were well balanced at baseline [mean HbA1c, 8.0%, FPG, 8.8 mmol/l (158 mg/dl); body mass index, 25.5 kg/m(2) ]. The adjusted mean change (AMΔ) in HbA1c at endpoint was -1.05 ± 0.08%, -0.92 ± 0.08% and -0.54 ± 0.08% in patients receiving vildagliptin 50 mg bid, 50 mg qd and placebo, respectively. The between-treatment difference (vildagliptin 50 mg bid-placebo) was -0.51 ± 0.11%, p < 0.001. A greater proportion of vildagliptin-treated patients met at least one responder criterion (82.1 and 70.7%) compared to placebo-treated patients (60.4%). The AMΔ at endpoint for FPG with vildagliptin 50 mg bid, -0.95 mmol/l (-17.1 mg/dl); 50 mg qd, -0.84 mmol/l (-15.1 mg/dl) was significantly different compared with the placebo -0.26 mmol/l (-4.68 mg/dl) (p ≤ 0.001). Adverse events (AEs) were reported as 34.2, 36.5 and 37.5% for patients receiving vildagliptin 50 mg bid, 50 mg qd or placebo, respectively. Two patients in the vildagliptin 50 mg qd and one in the placebo group reported serious AEs, which were not considered to be related to the study drug; one incidence of hypoglycaemic event was reported in the vildagliptin 50 mg bid group.

CONCLUSION

Vildagliptin as add-on therapy to metformin improved glycaemic control and was well tolerated in Chinese patients who were inadequately controlled by metformin only.

Pump-to-Stokes relative intensity noise transfer and analytical modeling of mid-infrared silicon Raman lasers

An analytical model for mid-infrared (mid-IR) silicon Raman lasers (SRLs) is developed. The relative intensity noise (RIN) transfer from the pump to the Stokes in the lasers is also investigated. The analytical model can be used as a versatile and efficient tool for analysis, design and optimization of mid-IR SRLs. It is shown that conversion efficiency of 70% is attainable and the low-frequency RIN transfer may be suppressed to below 1 dB by pumping low-loss waveguides at high intensities.

Cigarette smoking extract causes hypermethylation and inactivation of WWOX gene in T-24 human bladder cancer cells

Genomic, epigenetic and expression alterations of WW domain containing oxidoreductase (WWOX) have been implicated in multiple tumor types. The current study was designed to examine the expression of WWOX in tumor tissues of human bladder transitional cell carcinoma (BTCC) and the influence of cigarette smoke extract (CSE) on WWOX expression and methylation status in T-24 bladder cancer cells. WWOX protein expression was evaluated by immunohistochemistry staining in a series of tumor samples from 78 patients with BTCC and 26 normal bladder tissues. The expression level and methylation status of WWOX in CSE-treated cells were examined by using quantitative Real-Time RT-PCR and methylation specific PCR, respectively. The expression levels of DNA methyltransferases (DNMTs) 1, 3A and 3B were also detected. We found that WWOX expression was absent or reduced in 79.5% (62/78) of BTCC tissues, but only in 19.2% (5/26) of normal bladder tissues. Loss of WWOX expression was correlated with tumor grade (P=0.019) and cigarette smoking (P=0.031), but was not associated with age, gender, tumor size and tumor number. Hypermethylation of WWOX promoter and exon 1 was specifically induced by CSE with a kinetics concurrent to the suppression of WWOX mRNA in T-24 cells. Furthermore, CSE treatment induced a significant time-dependent increase in the level of DNMT1, but has no effects on DNMT3A and DNMT3B. Taken together, these novel findings suggest that hypermethylation of WWOX induced by cigarette smoking may represent one underlying mechanism for the loss expression of WWOX in bladder cancer.

Combination of valproic acid and ATRA restores RARβ2 expression and induces differentiation in cervical cancer through the PI3K/Akt pathway

Epigenetic silencing of the tumor suppressor gene, RARβ2, through histone deacetylation has been established as an important process of cervical carcinogenesis. This pivotal role has led to the suggestion that a combination of retinoids selective for RARβ2 with histone deacetylase (HDAC) inhibitors may have therapeutic potential. Valproic acid (VPA), a HDAC inhibitor, has a critical role in the regulation of gene expression through histone acetylation and causes transformed cells to undergo growth arrest, differentiation, and apoptosis. Therefore, we hypothesized that the combination of VPA and ATRA could restore RARβ2 expression, thus resulting in enhanced anti-neoplastic activity in cervical cancer. Here, we show that VPA combined with ATRA led to hyperacetylation of histone H3 and a significant alteration of gene expression in cervical cancer cells, including RARβ2 gene expression, which was upregulated 50- to 90-fold. The combination therapy effectively inhibited the growth of cervical cancer cells more than the single agent treatment both in vitro and in vivo. The additive effects were associated with a significant upregulation of p21(CIP1) and p53 as well as a pronounced decrease in p-Stat3. Furthermore, the combined treatment led to cell cycle arrest predominantly at the G1 phase, and it preferentially induced cell differentiation rather than apoptosis in cervical cancer cells. The differentiation program was determined by the presence of E-cadherinmediated adhesion and activation of the PI3K/Akt pathway. Taken together, these results provide new insight into the mechanisms of enhanced antitumor activity of the HDAC inhibitor and ATRA regimen, thus offering a new therapeutic strategy for cervical cancer patients.

The role of male chromosomal polymorphism played in spermatogenesis and the outcome of IVF/ICSI-ET treatment

Chromosomal polymorphism has been reported to be associated with infertility, but its effect on IVF/ICSI-ET outcome is still controversial. To evaluate whether or not chromosomal polymorphism in men plays a role in spermatogenesis and the outcome of IVF/ICSI-ET, we retrospectively analysed 281 infertile couples. Measures included fertilization rate, implantation rate, pregnancy rate, clinical pregnancy rate, ongoing pregnancy rate, early miscarriage rate and preterm rate. Men with chromosomal polymorphism had significantly higher frequencies of severe oligozoospermia and azoospermia than those without (37.12% vs. 16.11%, p < 0.001; 27.27% vs. 10.74%, p < 0.001; respectively). Significantly, lower fertilization rate (68.02% vs. 78.00%, p < 0.001) and clinical pregnancy rate (45.00% vs. 66.67%, p = 0.031) were observed in polymorphism-carrying men with severe oligozoospermia compared with non-carriers with severe oligozoospermia. This suggests that chromosomal polymorphism has adverse effects on spermatogenesis, negatively influencing the outcome of IVF/ICSI-ET treatment. Polymorphic variations on the Y chromosome have been found to be the most prevalent polymorphism in infertile men, most frequently occurring in patients with severe oligozoospermia.

Treatment of post-traumatic carotid-cavernous fistulas with the Willis covered stent. A preliminary prospective study

We describe our preliminary experience on the feasibility of using the Willis covered stent in patients with carotid-cavernous fistulas (CCFs). Eleven consecutive patients with post-traumatic CCFs referred for treatment with Willis covered stents were enrolled into this prospective study, and were subsequently followed-up at our hospital. Data on technical success, initial and final angiographic results, mortality, morbidity and final clinical outcome, was collected, with follow-up performed at one, three, six and 12 months, and yearly thereafter. Deployment of the covered stents was technically successful in all patients. Angiographic results following stent placement showed a complete occlusion in eight patients with ten CCFs, and an incomplete occlusion in three. No adverse events occurred either during or after the procedure. Angiographic follow-up (mean 14.73 ± 6.77 months) revealed complete occlusion and no obvious in-stent stenosis in all patients. Clinical follow-up (mean 17.73 ± 6.48 months) demonstrated full recovery in ten patients, and improvement in one. These preliminary results indicate that the use of the Willis covered stent is a feasible procedure, and that it may therefore serve as an alternative treatment for CCFs. Longer follow-up assessments and an expanded clinical trial are needed.

MicroRNA-337 is associated with chondrogenesis through regulating TGFBR2 expression

OBJECTIVE

MicroRNAs (miRNAs) have been implicated in regulating diverse cellular pathways and involved in development and inflammation. This study aimed to examine six miRNAs expression during the cartilage development and identify the key miRNA which is associated with chondrogenesis.

METHODS

The expression of six miRNAs in cartilage tissue during development was screened by real-time quantitative polymerase chain reaction (RT-qPCR). Rat models of bone matrix gelatin induced endochondral ossification, collagen-induced arthritis and pristane-induced arthritis were established to examine whether miR-337 is involved in chondrogenesis. Furthermore, the regulation of transforming growth factor-b type II receptor (TGFBR2) expression by miR-337 was determined with the luciferase reporter gene assay and Western blot. The expression of some specific genes relevant to cartilage tissue was tested by RT-qPCR after miR-337 mimic or inhibitor transfection.

RESULTS

MiR-337 expression was significantly down-regulated and almost disappeared in the maturation phases of endochondral ossification. The results of histology and RT-qPCR from three rat models showed that miR-337 is directly bound up with chondrogenesis. Furthermore, the results from the luciferase reporter gene assay and Western blot indicated that miR-337 regulated TGFBR2 expression. Our study also found that the enhancement of miR-337 may modulate the expression of cartilage-specific genes such as AGC1 in C-28/I2 chondrocytes.

CONCLUSION

We proved that miRNA-337 is associated with chondrogenesis through regulating TGFBR2 expression, and miRNA-337 can also influence cartilage-specific gene expression in chondrocytes. These findings may provide an important clue for further research in the arthritis pathogenesis and suggest a new remedy for arthritis treatment.

Graphene mode-locked femtosecond laser at 2 μm wavelength

We experimentally demonstrated a passively mode-locked femtosecond laser by using a graphene-based saturable absorber mirror (graphene SAM) in the spectral region of 2 μm. The graphene SAM was fabricated by transferring chemical-vapor-deposited, high-quality, and large-area graphene on a highly reflective plane mirror. Stable mode-locked laser pulses as short as 729 fs were obtained with a repetition rate of 98.7 MHz and an average output power of 60.2 mW at 2018 nm.

Fine structure analysis and sintering properties of Si-doped hydroxyapatite

Si-doped hydroxyapatite (Si-HA) has been intensively investigated as a promising bone biomaterial because of the biomineralization and bone formation benefit from silicon addition. In the current work, Si-HA samples were synthesized by the aqueous precipitation method. The sintering property of Si-HA was studied in terms of phase composition and transition, which was influenced by the Si doping percentage and sintering temperature. The results indicate that all the as-prepared and sintered low Si doping samples (Si% ≤ 1.6 wt%) possess HA phases; while the high Si doping samples (Si% ≥ 2 wt%) present amorphous phases as prepared, and largely or even completely transform to β-tricalcium phosphate (β-TCP) phase after sintering at 1250 °C. The Rietveld refinement on x-ray diffraction patterns was conducted to determine the particle sizes, microstrain factors and anisotropic distributions. According to the refined results, the calculated anisotropic particle sizes correspond to the observations made by transmission electron microscopy. The microstrains also present anisotropic distributions in all refinements. The accurate variation in the fine structure of Si-HA has been studied by the improved refinements after considering the anisotropic distribution.

Large intervening non-coding RNA HOTAIR is associated with hepatocellular carcinoma progression

Increasing evidence suggests that large intervening non-coding RNAs (lincRNAs) regulate key pathways in cancer invasion and metastasis. In this observational retrospective study, the expression of the oncogenic lincRNA HOX transcript antisense RNA (HOTAIR) gene was measured in 63 patients with hepatocellular carcinoma (HCC) following hepatic resection. The HOTAIR gene was significantly overexpressed in HCC tissues compared with adjacent non-tumour tissues. Patients with high HOTAIR gene expression in their tumours had an increased risk of recurrence after hepatectomy. There was also a significant correlation between HOTAIR expression and lymph node metastasis. In vitro assays in the HCC cell line Bel7402 demonstrated that knockdown of HOTAIR lincRNA reduced cell proliferation and was associated with reductions in levels of matrix metalloproteinase-9 and vascular endothelial growth factor protein, which are important for cell motility and metastasis. In conclusion, HOTAIR lincRNA might be a potential biomarker for the existence of lymph node metastasis in HCC.

Effects of variations in duodenal glucose load on glycaemic, insulin, and incretin responses in type 2 diabetes

AIMS

Postprandial glucagon-like peptide-1 (GLP-1) secretion and the 'incretin effect' have been reported to be deficient in Type 2 diabetes, but most studies have not controlled for variations in the rate of gastric emptying. We evaluated blood glucose, and plasma insulin, GLP-1 and glucose-dependent insulinotropic polypeptide (GIP) responses to intraduodenal glucose in Type 2 diabetes, and compared these with data from healthy controls.

METHODS

Eight males with well-controlled Type 2 diabetes, managed by diet alone, were studied on four occasions in single-blind, randomized order. Blood glucose, and plasma insulin, GLP-1, and GIP were measured during 120-min intraduodenal glucose infusions at 1 kcal/min (G1), 2 kcal/min (G2) and 4 kcal/min (G4) or saline control.

RESULTS

Type 2 patients had higher basal (P < 0.0005) and incremental (P < 0.0005) blood glucose responses to G2 and G4, when compared with healthy controls. In both groups, the stimulation of insulin and GLP-1 by increasing glucose loads was not linear; responses to G1 and G2 were minimal, whereas responses to G4 were much greater (P < 0.005 for each) (incremental area under the GLP-1 curve 224 ± 65, 756 ± 331 and 2807 ± 473 pmol/l.min, respectively, in Type 2 patients and 373 ± 231, 505 ± 161 and 1742 ± 456 pmol/l.min, respectively, in healthy controls). The GLP-1 responses appeared comparable in the two groups. In both groups there was a load-dependent increase in plasma GIP with no difference between them.

CONCLUSIONS

In patients with well-controlled Type 2 diabetes, blood glucose, insulin and GLP-1 responses are critically dependent on the small intestinal glucose load, and GLP-1 responses are not deficient.

Single- and double-SSR primer combined analyses in rice

Polymerase chain reaction (PCR) is the foundation of SSR molecular marker technology. We used sib rice varieties J518, XD1 and SD23 as experimental materials, selecting 30 pairs of SSR primers, including RM127, RM337 and RM5172, covering the rice genome, and performed single- and double-SSR primer combined analyses. We found that under the same PCR system and conditions, a single primer of the SSR primer pairs could amplify the same fragments as double primers do. The sequencing results demonstrated that some amplified fragments that we previously believed to come from double primers were actually produced by a single primer. The use of this kind of primer, such as the RM127 primer pair, for marker-assisted breeding will therefore be misleading. Additionally, using the same PCR system and conditions, some single primers that are part of SSR primer pairs can amplify many more specific fragments than double-SSR primers. For instance, in the case of the RM5172 primer pair, a single primer P1 amplified approximately three times the number of fragments as the double primer. This information can contribute to research on genetic diversity of species, understanding of genetic relationships and identification of germplasm resources. Accordingly, combined analyses of single- and double-primer amplification products not only can remove single-primer amplification fragments and false-positives from double-primer amplification products in order to improve test accuracy, but also can facilitate research on genetic diversity, exploration of phylogenetic relationships and identification of germplasm resources. We define this method as "single- and double-SSR primer combined analyses".