Surface-Roughened SERS-Active Single Silver Nanowire for Simultaneous Detection of Intracellular and Extracellular pHs

The simultaneous and accurate detection of intracellular pH (pH_i) and extracellular pH (pH_e) is essential for studying the complex physiological activities of cancer cells and exploring pH-related therapeutic mechanisms. Here, we developed a super-long silver nanowire-based surface-enhanced Raman scattering (SERS) detection strategy for simultaneous sensing of pH_i and pH_e. A surface-roughened silver nanowire (AgNW) with a high aspect ratio is prepared at a nanoelectrode tip using a Cu-mediated oxidation process, which is then modified by pH-sensitive 4-mercaptobenzoic acid (4-MBA) to form 4-MBA@AgNW as a pH sensing probe. With the assistance of a 4D microcontroller, 4-MBA@AgNW is efficient in simultaneously detecting pH_i and pH_e in both 2D and 3D culture cancer cells by SERS, with minimal invasiveness, high sensitivity, and spatial resolution. Further investigation proves that the surface-roughened single AgNW can also be used in monitoring the dynamic variation of pH_i and pH_e of cancer cells upon stimulation with anticancer drugs or under a hypoxic environment.

Single-Molecule Electrical and Spectroscopic Profiling Protein Allostery Using a Gold Plasmonic Nanopore

Direct structural and dynamic characterization of protein conformers in solution is highly desirable but currently impractical. Herein, we developed a single molecule gold plasmonic nanopore system for observation of protein allostery, enabling us to monitor translocation dynamics and conformation transition of proteins by ion current detection and SERS spectrum measurement, respectively. Allosteric transition of calmodulin (CaM) was elaborately probed by the nanopore system. Two conformers of CaM were well-resolved at a single-molecule level using both the ion current blockage signal and the SERS spectra. The collected SERS spectra provided structural evidence to confirm the interaction between CaM and the gold plasmonic nanopore, which was responsible for the different translocation behaviors of the two conformers. SERS spectra revealed the amino acid residues involved in the conformational change of CaM upon calcium binding. The results demonstrated that the excellent spectral characterization furnishes a single-molecule nanopore technique with an advanced capability of direct structure analysis.

Single Molecule Protein Segments Sequencing by a Plasmonic Nanopore

Obtaining sequential and conformational information on proteins is vital to understand their functions. Although the nanopore-based electrical detection can sense single molecule (SM) protein and distinguish among different amino acids, this approach still faces difficulties in slowing down protein translocation and improving ionic current signal-to-noise ratio. Here, we observe the unfolding and multistep sequential translocation of SM cytochrome c (cyt c) through a surface enhanced Raman scattering (SERS) active conical gold nanopore. High bias voltage unfolds SM protein causing more exposure of amino acid residues to the nanopore, which slows down the protein translocation. Specific SERS traces of different SM cyt c segments are then recorded sequentially when they pass through the hotspot inside the gold nanopore. This study shows that the combination of SM SERS with a nanopore can provide a direct insight into protein segments and expedite the development of nanopore toward SM protein sequencing.

Super-Long SERS Active Single Silver Nanowires for Molecular Imaging in 2D and 3D Cell Culture Models

Establishing a systematic molecular information analysis strategy for cell culture models is of great significance for drug development and tissue engineering technologies. Here, we fabricated single silver nanowires with high surface-enhanced Raman scattering activity to extract SERS spectra in situ from two-dimensional (2D) and three-dimensional (3D) cell culture models. The silver nanowires were super long, flexible and thin enough to penetrate through multiple cells. A single silver nanowire was used in combination with a four-dimensional microcontroller as a cell endoscope for spectrally analyzing the components in cell culture models. Then, we adopted a machine learning algorithm to analyze the obtained spectra. Our results show that the abundance of proteins differs significantly between the 2D and 3D models, and that nucleic acid-rich and protein-rich regions can be distinguished with satisfactory accuracy.

Secondary coronary artery ostial lesions: Three case reports

BACKGROUND

Atherosclerosis is one of the main causes of coronary artery ostial lesions seen clinically. Secondary coronary artery ostial lesions are rare, and cases reported previously were associated with syphilitic vasculitis and aortic dissection. Here, we report three rare cases of secondary coronary ostial lesions. Due to their rareness, these lesions can easily be neglected, which may lead to misdiagnosis and missed diagnosis.

CASE SUMMARY

We present three patients with acute myocardial infarction and unstable angina caused by secondary coronary artery ostial lesions. In Case 1, coronary angiography (CAG) revealed 90% stenosis of the left main coronary ostium. Chest contrast computed tomography (CT) suggested thymic carcinoma invading the left main coronary ostium. Coronary artery bypass grafting and tumor resection were performed. In Case 2, echocardiography revealed a sinus of Valsalva aneurysm (SVA)-like dilatation. CAG showed a right coronary sinus giant aneurysm and complete obstruction of the right coronary artery (RCA) ostium. Aortic contrast CT confirmed these findings. The Bentall procedure was performed. In Case 3, CT CAG identified an anomalous origin of the right coronary artery (AORCA) from the left sinus of Valsalva coursing between the aorta and pulmonary trunk, causing severe RCA ostium stenosis by compression. Surgical correction of the AORCA was performed.

CONCLUSION

The cases reported here suggest that we should consider other causes of coronary ostial lesions other than atherosclerosis.

High Spatial Resolution of Ultrathin Covalent Organic Framework Nanopores for Single-Molecule DNA Sensing

Ultrathin nanosheets of two-dimensional covalent organic frameworks covered a quartz nanopipette and then acted as a nanopore device for single-molecule DNA sensing. Our results showed that a single DNA homopolymer as short as 6 bases could be detected. The dwell times of 30-mer DNA homopolymers were obviously longer than the times of 10- or 6-mer ones. For different bases, poly(dA)₆ showed the slowest transport speed (∼595 μs/base) compared with cytosine (∼355 μs/base) in poly(dC)₆ and thymine (∼220 μs/base) in poly(dT)₆. Such translocation speeds are the slowest ever reported in two-dimensional material-based nanopores. Poly(dA)₆ also showed the biggest current blockade (94.74 pA) compared with poly(dC)₆ (79.54 pA) and poly(dT)₆ (71.41 pA). However, the present difference in blockade current was not big enough to distinguish the four DNA bases. Our study exhibits the shortest single DNA molecules that can be detected by COF nanopores at the present stage and lights the way for DNA sequencing based on solid-state nanopores.

Jieduquyuziyin Prescription alleviates hepatic gluconeogenesis via PI3K/Akt/PGC-1α pathway in glucocorticoid-induced MRL/lpr mice

ETHNOPHARMACOLOGICAL RELEVANCE

Jieduquyuziyin prescription (JP) is a traditional Chinese medicine (TCM) formula. According to both TCM theory and more than a decade of clinical practice, JP has been testified to be effective for systemic lupus erythematosus (SLE) treatment as an approved hospital prescription in China.

AIM OF THE STUDY

To determine the effect of JP on the treatment of SLE by glucocorticoid (GC) and to further examine the molecular mechanisms.

MATERIALS AND METHODS

We conducted in vivo experiments to estimate the effect of JP on hepatic gluconeogenesis in MRL/lpr mice treated with GC. Additionally, isoproterenol (ISO) induced hepatic gluconeogenesis model and GC-treated MRL/lpr mouse hepatocytes were carried out in vitro experiments to verify the effect of JP on gluconeogenesis.

RESULTS

The results showed that JP combined with GC could effectively alleviate the lupus symptoms in MRL/lpr mice and improve the pathological changes of the kidney and liver. And the combination of JP reduced the side effects caused by GC, which was related to the inhibition of GC-induced hepatic gluconeogenesis in MRL/lpr mice. Specifically, JP up-regulated the expression of glucocorticoid receptor (GR) α, phosphoinositide-3-kinase (PI3K) and Akt restrained by GC to reduce the production of forkhead box O1 (FoxO1), peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α), and the gluconeogenic genes phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase). In vivo, the use of JP either alone or with GC could reduce spleen enlargement, high levels of serum antibodies, aggravated urine protein and renal pathological damage in MRL/lpr mice. Furthermore, the glucose content was reduced in the liver of MRL/lpr mice treated with JP, and the liver damage and steatosis were also alleviated. In vitro, the expressions of PI3K and Akt increased and the expressions of FoxO1, PGC-1α, PEPCK and G6Pase decreased after JP treatment in ISO-treated hepatocytes. Compared with MRL/MP mice, we found that JP could significantly inhibit the expression of gluconeogenesis in the hepatocytes of MRL/lpr mice induced by GC to a greater extent.

CONCLUSIONS

The therapeutic effect of JP on GC-induced is likely related to hepatic gluconeogenesis, which provides a new perspective to reveal the positive role of JP in SLE.

Single Molecule DNA Analysis Based on Atomic-Controllable Nanopores in Covalent Organic Frameworks

We explored the application of two-dimensional covalent organic frameworks (2D COFs) in single molecule DNA analysis. Two ultrathin COF nanosheets were exfoliated with pore sizes of 1.1 nm (COF-1.1) and 1.3 nm (COF-1.3) and covered closely on a quartz nanopipette with an orifice of 20 ± 5 nm. COF nanopores exhibited high size selectivity for fluorescent dyes and DNA molecules. The transport of long (calf thymus DNA) and short (DNA-80) DNA molecules through the COF nanopores was studied. Because of the strong interaction between DNA bases and the organic backbones of COFs, the DNA-80 was transported through the COF-1.1 nanopore at a speed of 270 μs/base, which is the slowest speed ever observed compared with 2D inorganic nanomaterials. This study shows that the COF nanosheet can work individually as a nanopore monomer with controllable pore size like its biological counterparts.

[Urinary retinol binding protein and β2-microglobulin were associated with urinary albumin to creatinine ratio and renal function in hospitalized diabetic patients]

Objective: To explore the associations of urinary retinol binding protein (RBP) and β₂-microglobulin (β₂-MG) with urinary albumin to creatinine ratio (UACR) and renal function in hospitalized patients with type 2 diabetes mellitus (T2DM). Methods: A total of 1 030 Chinese patients with T2DM were included in this study. The subjects were divided into the UACR normal group (<30 mg/g), microalbuminuria group (30-300 mg/g) and macroalbuminuria group (>300 mg/g). Patients with normal UACR were further divided into two groups according to the estimated glomerular filtration rate (eGFR): the eGFR low group (<90 ml·min^-1·1.73m^-2) and the normal eGFR group (≥90 ml·min^-1·1.73m^-2). Urine RBP and β₂-MG levels among the groups were compared. Multiple linear regression analyses were applied to evaluate risk factors of urine RBP and β₂-MG. Results: In all patients (n=1 030), urine RBP and β₂-MG increased gradually with the increase of UACR across the three groups, the proportions of abnormal urine RBP (>0.7 mg/L) and β₂-MG (>370 μg/L) in these groups were 3.8%, 8.5%, 39.0% (P<0.001), and 12.9%, 26.7%, 46.8% (P<0.001), respectively. In the UACR normal group (n=788), 12.2% of the patients were with eGFR<90 ml·min^-1·1.73m^-2. The proportion of abnormal β₂-MG (>370 μg/L) was higher in the eGFR low group than that in the eGFR normal group (29.2% vs. 10.7%, P<0.001). Multivariate linear stepwise regression analyses were performed using natural logarithm of urine RBP or β₂-MG as dependent variable, and showed that urine RBP was independently associated with UACR (β=0.0005, P<0.001), serum creatinine (β=0.006, P<0.001) and glycosylated hemoglobin A1c (β=0.050, P=0.001), and β₂-MG was independently correlated with UACR (β=0.000 4, P<0.001), serum creatinine (β=0.011, P<0.001), systolic blood pressure (β=0.005, P=0.031) and fasting blood-glucose (β=0.027, P=0.046). Conclusions: Urine RBP and β₂-MG are positively associated with high UACR and impaired renal function in T2DM patients, and these changes could occur before UACR and eGFR turned out to be abnormal. It is recommended that urine RBP and β₂-MG be detected as early as possible to identify diabetic kidney disease in patients with normal UACR and eGFR.

SERS Detection of Nucleobases in Single Silver Plasmonic Nanopores

Conventional ion current-based nanopore techniques that identify single molecules are hampered by limitations of providing only the ionic current information. Here, we introduce a silver nanotriangle-based nanopore (diameter < 50 nm) system for detecting molecule translocation using surface-enhanced Raman scattering. Rhodamine 6G is used as a model molecule to study the effect of an electric field (-1 V) on the mass transport. The four DNA bases also show significantly different SERS signals when they are transported into the plasmonic nanopore. The observations suggest that in the electric field, analyte molecules are driven into the nanopipette through the hot spot of the silver nanopore. The plasmonic nanopore shows great potential as a highly sensitive SERS platform for detecting molecule transport and paves the way for single molecule probing.

[Application of the superior thyroid artery peak systolic velocity in differentiating Graves' disease from autoimmune thyroiditis]

Objective: To evaluate the clinical value of the superior thyroid artery peak systolic velocity (STA-PSV) for the differential diagnosis of autoimmune thyrotoxicosis. Methods: A total of 301 patients with newly diagnosed thyrotoxicosis and without any anti-thyroid drug intervention were collected from the Department of Endocrinology and Metabolism, Peking University People's Hospital from Jan. 2015 to Oct. 2018. Among them, 241 patients were with Graves' disease (GD) and 60 patients were with autoimmune thyroiditis (AIT). STA-PSV, thyroid function and thyrotropin receptor antibody (TRAb) were determined. A multiple linear regression was used to identify factors associated with STA-PSV. A receiver operating characteristic (ROC) curve and area under the curve (AUC) were used to evaluate the discriminating ability of STA-PSV to GD. Results: STA-PSV leves in GD group were significantly higher than those in AIT group [61.00 (41.00, 86.50) cm/s vs. 34.50 (25.25, 46.00) cm/s, P<0.001]. The ROC curve analysis showed that the AUC was 0.790 (95%CI 0.734-0.845), and 49.5cm/s was the optimal cutoff point for the diagnosis of GD, in which the sensitivity was 64.3% and the specificity was 83.3%. In all patients with thyrotoxicosis, multiple linear regression analyses showed free thyroxine (FT(4)) (β=0.371, 95%CI 0.005-0.010, P<0.001) and TRAb (β=0.138, 95%CI 0.001-0.014, P=0.035) were positively associated with STA-PSV. Conclusions: The STA-PSV is positively associated with FT(4) and TRAb levels, and it is a helpful marker in differential diagnosis between GD and AIT.

Clinical features of pediatric patients with COVID-19: a report of two family cluster cases

BACKGROUND

Coronovirus disease 2019 (COVID-19) has spread rapidly across the globe. People of all ages are susceptible to COVID-19. However, literature reports on pediatric patients are limited.

METHODS

To improve the recognition of COVID-19 infection in children, we retrospectively reviewed two confirmed pediatric cases from two family clusters. Both clinical features and laboratory examination results of the children and their family members were described.

RESULTS

The two confirmed children only presented with mild respiratory or gastrointestinal symptoms. Both of them had normal chest CT images. After general and symptomatic treatments, both children recovered quickly. Both families had travel histories to Hubei Province.

CONCLUSIONS

Pediatric patients with COVID-19 are mostly owing to family cluster or with a close contact history. Infected children have relatively milder clinical symptoms than infected adults. We should attach importance to early recognition, early diagnosis, and early treatment of infected children.

[Mycophenolate mofetil versus cyclosporine A in children with primary refractory nephrotic syndrome]

Objective: To compare the efficacy and safety of mycophenolate mofetil versus cyclosporine A in treating children with primary refractory nephrotic syndrome. Methods: Conducted a prospective randomized controlled clinical trial in 62 pediatric patients (including 44 boys and 18 girls), age ranged from 2.1 to 17.0 years; 32 cases presented with frequently relapsing nephrotic syndrome (FRNS) and 30 cases presented with steroid-resistant nephrotic syndrome (SRNS), who were admitted to department of Nephrology, Children's Hospital Affiliated to Capital Institute of Pediatrics from October 2013 to October 2015. The patients received either mycophenolate mofetil (20-30)mg/(kg·d) or cyclosporine A (3-5)mg/(kg·d) randomly, on the basis of prednisone treatment. Follow-up interview was conducted regularly for at least one year. Efficacy rate, relapse rate, time required for induction of remission, relapse-free period and prednisone dosage were compared between the two groups. Results: (1) Renal histologic examination, which was available for 17 patients, revealed minimal change disease in 8 patients, mesangial proliferative glomerulonephritis (MsPGN) in five, membranous nephropathy in two, and focal segmental glomerulosclerosis (FSGS) in two. (2) Comparison of mycophenolate mofetil versus cyclosporine A in children with FRNS: There were 14 patients with FRNS in mycophenolate mofetil group and 18 patients with FRNS in cyclosporine A group respectively. The relapse rate (episodes/year) in cyclosporine A group was lower than that of mycophenolate mofetil group (1.0 (0.0, 1.0) vs. 1.0 (1.0, 3.0), Z=-2.405, P=0.016). The relapse-free period (months) in cyclosporine A group was longer than that of mycophenolate mofetil group (10.0 (5.7, 12.1) vs. 5.0 (1.0, 11.0), Z=-1.984, P=0.047). No significant difference in dosage of prednisone was found between cyclosporine A and mycophenolate mofetil groups when followed up for 1 year. (3) Comparison of mycophenolate mofetil versus cyclosporine A in children with SRNS: The efficacy rate was 6/14 in mycophenolate mofetil group and 13/16 in cyclosporine A group. The complete remission rate was 4/14 in mycophenolate mofetil group and 12/16 in cyclosporine A group (P<0.05). The time (months) required for induction of remission in cyclosporine A group was significantly shorter than that of mycophenolate mofetil group (1.0 (1.0, 2.0) vs. 3.0 (2.5, 4.0), Z=-2.529, P=0.011). No significant differences were found between the two groups with respect to relapse-free period and relapse rate. (4) Except that one patient developed hypertensive encephalopathy in cyclosporine A group, no other serious adverse events were recorded. There were no significant differences between two groups with respect to adverse events. Conclusion: Our results indicated that both mycophenolate mofetil and cyclosporine A were effective in the treatment of children with refractory nephrotic syndrome. Cyclosporine A was superior to mycophenolate mofetil in preventing relapses in patients with FRNS and inducing complete remission in patients with SRNS. Although most patients were able to tolerate mycophenolate mofetil and cyclosporine A, but the toxicity and safety of cyclosporine A should be monitored closely.

[The influence of different thyroid stimulating hormone cut-offs to diagnose subclinical hypothyroidism during the first trimester of pregnancy]

Objective: To analyze the influence of different thyroid stimulating hormone (TSH) cut-offs to diagnose subclinical hypothyroidism (SCH) in the first trimester of gestation. Methods: A total of 896 pregnant women were enrolled in Peking University International Hospital between October 2016 and March 2018. Among them, 421 pregnant women with single fetus who were conformed to the criteria of National Academy of Clinical Biochemistry (NACB), without adverse pregnancy outcomes and obstetric complications, were selected to establish their self-sequential longitudinal reference ranges of thyroid function. Then, SCH was diagnosed in the first trimester, using different TSH cutoffs, such as the upper limit of the first trimester-specific reference range, 4.0 mU/L recommended by the 2017 Guidelines of American Thyroid Association (ATA), 5.17 mU/L (Roche reagent) recommended by 2012 Guidelines of Chinese Society of Endocrinology and Chinese Society of Perinatal Medicine, and 2.5 mU/L recommended by 2011 Guidelines of ATA, respectively. Results: The TSH reference range was 0.12-4.16 mU/L in the first trimester. Using TSH>4.16, 4.0, 5.17 and 2.5 mU/L to diagnose SCH in the first trimester, the prevalence rates were 4.35% (39/896), 5.92% (53/896), 1.56% (14/896) and 20.87% (187/896), respectively. There was no statistically significant difference between the prevalence rates of SCH using the TSH upper reference limit of 4.0 mU/L and 4.16 mU/L (P=0.134). When TSH was defined as>4.0 mU/L to diagnose SCH, the sensitivity, specificity and Youden index was 97.4%, 98.2%, and 0.956, respectively. Conclusions: The TSH upper reference limit of 4.0 mU/L recommended by 2017 Guidelines of ATA can be used as a cut-off to diagnose SCH in first trimester for the areas without trimester-specific reference ranges for TSH in China.

Nanopipette-Based SERS Aptasensor for Subcellular Localization of Cancer Biomarker in Single Cells

Single cell analysis is essential for understanding the heterogeneity, behaviors of cells, and diversity of target analyte in different subcellular regions. Nucleolin (NCL) is a multifunctional protein that is markedly overexpressed in most of the cancer cells. The variant expression levels of NCL in subcellular regions have a marked influence on cancer proliferation and treatments. However, the specificity of available methods to identify the cancer biomarkers is limited because of the high level of subcellular matrix effect. Herein, we proposed a novel technique to increase both the molecular and spectral specificity of cancer diagnosis by using aptamers affinity based portable nanopipette with distinctive surface-enhanced Raman scattering (SERS) activities. The aptamers-functionalized gold-coated nanopipette was used to capture target, while p-mercaptobenzonitrile (MBN) and complementary DNA modified Ag nanoparticles (AgNPs) worked as Raman reporter to produce SERS signal. The SERS signal of Raman nanotag was lost upon NCL capturing via modified DNA aptamers on nanoprobe, which further helped to verify the specificity of nanoprobe. For proof of concept, NCL protein was specifically extracted from different cell lines by aptamers modified SERS active nanoprobe. The nanoprobes manifested specifically good affinity for NCL with a dissociation constant Kd of 36 nM and provided a 1000-fold higher specificity against other competing proteins. Furthermore, the Raman reporter moiety has a vibrational frequency in the spectroscopically silent region (1800-2300 cm-1) with a negligible matrix effect from cell analysis. The subcellular localization and spatial distribution of NCL were successfully achieved in various types of cells, including MCF-7A, HeLa, and MCF-10A cells. This type of probing technique for single cell analysis could lead to the development of a new perspective in cancer diagnosis and treatment at the cellular level.

[Study on UPLC fingerprint of red ginseng based on good separation and good purity of chromatographic peaks]

This study is to establish the UPLC fingerprint of red ginseng. The separation was performed on a Waters Acquity BEH C₁₈ column (2.1 mm × 50 mm,1.7 μm), with the mobile phase consisting of acetonitrile and water for gradient elution. The detection wavelength was set at 203 nm. The UPLC fingerprint of red ginseng was established by using sample chromatography of 22 different purchase areas and 26 common peaks were found. Compared with the reference substances, 11 of the common peaks were identified as ginsenosides Rg₁, ginsenoside Re, ginsenoside Rf, ginsenoside Rh₁, ginsenoside Rg₂, ginsenoside Rb₁, 20(S)-ginsenoside F₁, ginsenoside Rb₂, ginsenoside Rb3, 20(S)-ginsenoside Rg₃ and 20(R)-ginsenoside Rg₃, respectively. It is worth noting that 20(S)-ginsenoside Rg₃ and 20(R)-ginsenoside Rg₃ are the characteristic ingredients of red ginseng, and they could be used not only for distinguishing red ginseng and ginseng, but also for process controlling of the preparation of red ginseng. The similarity was analyzed with' Similarity Evaluation System for Chromatographic Fingerprint of Chinese Materia Medica, and the similarity of 18 batches samples is up to 0.9. Compared to the literature methods, the method is simple, time-saving,specific for the separation of ginsenosides from red ginseng. So, this method could be used for the species identification and quality control of ginseng, red ginseng and American ginseng, and it will alsoprovide a theoretical basis of raising quality standards of the above mentioned Chinese herb medicines.

[Quantitative analysis of nine ginsenosides in red ginseng using QAMS method based on high-resolution and reference chromatography of red ginseng]

Using reversed-phase high performance liquid chromatography, nine ginsenosides were simultaneously separated on an UltimateC₁₈ column with high-resolution and high purity of each chromatographic peak. Adopting the QAMS quality evaluation model for traditional Chinese medicines, ginsenoside Rb₁ was used as the internal reference substance, and the relative correction factors (RCFs) and the relative retention values (RTRs) of ginsenosides Rg₁, Re, Rf, Rb₁, Rc, Rb₂, Rb₃, Rd and 20 (S)-ginsenoside Rg₃ to ginsenoside Rb₁ were calculated individually. Through a series of methodology evaluations, and positioned by the red ginseng reference chromatograph and RTVs, nine ginsenosides in red ginseng were simultaneously assayed only by quantitative determined ginsenoside Rb₁.

[A prospective, randomized, controlled clinical study of Huai Qi Huang granules in treatment of childhood primary nephrotic syndrome]

OBJECTIVE

To study the efficacy of Huai Qi Huang granules in the treatment of childhood primary nephrotic syndrome.

METHODS

Between July 2009 and December 2011, patients who were admitted and diagnosed for the first time as childhood primary nephrotic syndrome were randomized into a treatment group (Huai Qi Huang granules plus glucocorticoid; n=23) and a control group (glucocorticoid alone; n=19) for a prospective study. The two groups were compared for regression time of edema, time to urinary protein clearance, relapse rate, incidence of infection, dosage of glucocorticoid, and humoral and cellular immunological indicators.

RESULTS

There were no significant differences in regression time of edema, time to urinary protein clearance, and relapse rate between the treatment and control groups (P>0.05). The treatment group had significantly lower incidence of infection and daily dose of glucocorticoid (at month 6) than the control group (P<0.05). Humoral and cellular immunological indicators showed no significant differences between the two groups (P>0.05). No Huai Qi Huang-related adverse events were observed in this study.

CONCLUSIONS

Huai Qi Huang granules treatment can reduce the dose of glucocorticoid and the incidence of infection in children with primary nephrotic syndrome and has a favourable safety.

Donnan potential caused by polyelectrolyte monolayers

The Donnan potential is successfully isolated from ion pair potential on a ferrocene-labeled polyelectrolyte (DNA) monolayer. The isolated Donnan potential shifts negatively upon the increase in NaClO4 concentration with a slope of -58.8 mV/decade. With the salt concentration grown up to 1 M, the stretched DNA chains in low salt concentration are found to experience a gradual conformation relaxing process. At salt concentrations higher than 2 M, Donnan breakdown occurs where only the ion pair effect modulates the apparent potential. The apparent formal potential also shows strong dependence on solution pH, which reveals that the charge density in the polyelectrolyte monolayer plays an important role in the establishment of Donnan equilibrium.

[Determination of eight ginsenosides in renshenshouwu capsules by HPLC-DAD]

OBJECTIVE

To establish an HPLC-DAD method for simultaneous determination of eight ginsenosides in Renshenshouwu capsules.

METHOD

Ultimate C18 column (4.6 mm x 250 mm, 5 microm) was adopted for gradient elution, with acetonitrile and water as the mobile phase. The flow rate was 1 mL x min(-1), the column temperature was set at 30 degrees C, and the detection wavelength was 203 nm.

RESULT

A good linearity was observed in the range of 0.242-12.1, 0.222-11.1, 0.251-25.1, 0. 245-24.5, 0.232-23.2, 0.232-23.2, 0.264-26.4, 0.244-24.4 microg for ginsenoside Rg1, Re, Rb1, Rc, Rb2, Rb3, Rd and 20(S)-ginsenoside Rg3, respectively, with the average recoveries of 102.7%, 103.2%, 101.6%, 101.2%, 102.0%, 100.7%, 101.9%, 102.0%, respectively.

CONCLUSION

The method was so simple, accurate and effective that it could be used for quality control of the above eight components in Renshenshouwu capsules.

[Experimental study on effect of different chromatographic conditions on QAMS relative correlation factors and relative retention values]

OBJECTIVE

To investigate the effect of different chromatographic conditions on QAMS relative correlation factors (RCF) and relative retention values (RT(R)).

METHOD

C18 columns were used with methyl alcohol-0.4% phosphoric acid water (85: 15) as the mobile phase. The detection wavelength was 254 nm, the column temperature was 30 degrees C, and the flow rate was 1.0 mL x min(-1). The five anthraquinones in Rhei Radix et Rhizoma were selected to be the objects of study. The RCF and RT(R) among aloe-emodin, rhein, chrysophanol, physcion and emodin were determined under different chromatographic conditions.

RESULT

Their RCFs showed no significant difference.

CONCLUSION

The RCFs among anthraquinones established by QAMS can be used as a constant in content determination of traditional Chinese medicines/patent traditional Chinese medicines.

[Evaluation of the clinical and imaging examination in high-risk children with vesicoureteral reflux]

OBJECTIVE

To analyze the clinical data and result of voiding cystourethrography (VCUG) in high-risk children with vesicoureteral reflux (VUR) for better awareness of VUR, and to assess the usefulness of non-radioactive voiding ultrasonography (VUS) in the diagnosis of VUR.

METHOD

Ninety-three high-risk children with VUR who were hospitalized from July 2007 to April 2010 were studied. The study included 58 cases of urinary tract infection (UTI) and 35 cases of fetal or postnatal hydronephrosis detected on a B ultrasound scan. The results of urinalysis, urine culture, renal function, B ultrasound and VCUG were evaluated. Part of patients underwent VUS followed by VCUG immediately.

RESULT

(1) Sixty-two boys and 31 girls (aged 1 month to 11.5 years, mean age 2 years) were included. VUR was detected in 26 patients (28%) by VCUG. In terms of kidney-ureter units, VUR was detected in 36 of 186 kidney-ureter units, including 6 grade I, 3 grade II, 6 grade III, 15 grade IV and 6 grade V. (2) VUR was detected in 20 of 58 UTI patients (34.5%) by VCUG. The proportion of VUR in recurrent UTI group was 61.1%, much higher than that in first UTI group (22.5%). Thirteen of 20 VUR (65%) occurred in UTI patients under 1 year of age (M/F 10/3), with more bilateral VUR and severe grades of VUR than the older group. VUR was detected in 6 of 35 fetal or postnatal hydronephrosis patients (17.1%) by VCUG. (3) Twenty-two patients underwent both VUS and VCUG. VUR was detected in 4 patients and 6 kidney-ureter units by VCUG, while in 6 patients and 9 kidney-ureter units by VUS. Taking VCUG as the reference standard, VUS had a sensitivity of 100%, specificity of 92.1%, positive predictive value of 66.7%, and negative predictive value of 100%. There was a concordance rate of 93.2% between VUS and VCUG.

CONCLUSION

It is important to early screen VUR in UTI, fetal or postnatal hydronephrosis patients. There are more VUR, especially more bilateral VUR and severe grades of VUR, occurred in UTI patients under 1 year of age compared to older children. The incidence of VUR in recurrent UTI group was much higher than that in first UTI group. VUS is an accurate, reliable and radiation-free technique for the detection of VUR. It could be used to screen high-risk children for VUR and do the evaluation in the follow-up of VUR.

Performance of HbA(1c) for detecting newly diagnosed diabetes and pre-diabetes in Chinese communities living in Beijing

AIM

To determine the performance of glycated haemoglobin (HbA(1c)) as a screening tool for detecting newly diagnosed diabetes (NDM) and pre-diabetes.

METHODS

A diabetes survey was conducted in Beijing among community dwellers who were willing to participate in the survey. Included in the survey were 903 individuals aged 21-79 years without previously diagnosed diabetes and in whom HbA(1c) and other required covariates had been measured. NDM and pre-diabetes (impaired glucose tolerance + impaired fasting glucose) were defined according to the World Health Organization 1999 criteria based on 75-g oral glucose tolerance test. Receiver operating characteristic curve (ROC) was plotted to determine the performance of HbA(1c).

RESULTS

The prevalence of NDM and pre-diabetes was 11.1% and 22.4%, respectively. At an optimal HbA(1c) cut-off point of > or = 6.0%, the test gave a sensitivity of 80.0% and a specificity of 89.8% for diagnosing NDM; at an optimal cut-off point of > or = 5.7%, the sensitivity was 59.4% and specificity 73.9% for diagnosing pre-diabetes. Individuals with HbA(1c)> or = 6.0% tended to be more obese than those with HbA(1c) < 6.0%, but blood pressure and lipid profiles did not differ between the two groups.

CONCLUSIONS

HbA(1c) as a single screening test is adequate to detect newly diagnosed diabetes but is not able to identify pre-diabetes in this obese Chinese population.

Exon sequencing and association analysis of polymorphisms in TCF7L2 with type 2 diabetes in a Chinese population

AIMS/HYPOTHESIS

Recently, variants in the transcription factor 7-like 2 (TCF7L2) gene have been found to be consistently associated with type 2 diabetes in different populations. In this study, we hypothesized that TCF7L2 also contributed to genetic susceptibility for type 2 diabetes in a Chinese population.

METHODS

We looked for new variants by direct sequencing of all exons and intron-exon junctions of TCF7L2 in 100 Chinese type 2 diabetic patients, and then we genotyped five single nucleotide polymorphisms (SNPs) by Snapshot technology in 1,000 Chinese individuals.

RESULTS

By sequencing, we identified six SNPs (c.1,637C>A; c.1,674C>G; c.1,709G>A; c.1,846C>G; c.1,888C>T; and c.1,876T>G), and three of them led to non-synonymous polymorphisms (c.1,637C>A, His-->Gln or Pro-->Thr; c.1,674C>G, Pro-->Arg; and c.1,709G>A, Ala-->Thr). All of them are rare except c.1,637C>A, which had a frequency of 0.23 for the minor A allele in 98 sequenced individuals. In a case-control study, one of the newly discovered SNPs (c.1,637C>A), together with four reported ones (rs7903146, rs12255372, rs290487 and rs3814573) were genotyped. Comparison between allele and genotype frequencies of these SNPs in patients and controls showed marginal association for rs7903146 and rs290487 with type 2 diabetes (p = 0.063, OR 1.982, 95% CI 1.128-3.485; p = 0.071, OR 1.237, 95% CI 0.983-1.557, respectively). No association was found for rs12255372, rs3814573, c.1,637C>A and type 2 diabetes (p = 0.278-1.000).

CONCLUSIONS/INTERPRETATION

With the current sample size, we did not find any mutation in the coding sequence of TCF7L2 that confers a genetic risk for type 2 diabetes in a Chinese population, and did not replicate some of the major positive results obtained in other populations.

Acceleration of alpha-synuclein aggregation by homologous peptides

alpha-Synuclein (alpha-Syn), amyloid beta-protein and prion protein are among the amyloidogenic proteins that are associated with the neurodegenerative diseases. These three proteins share a homologous region with a consensus sequence mainly consisting of glycine, alanine and valine residues (accordingly named as the GAV motif), which was proposed to be the critical core for the fibrillization and cytotoxicity. To understand the role of the GAV motif in protein amyloidogenesis, we studied the effects of the homologous peptides corresponding to the sequence of GAV motif region (residues 66-74) on alpha-Syn aggregation. The result shows that these peptides can promote fibrillization of wild-type alpha-Syn and induce that of the charge-incorporated mutants but not the GAV-deficient alpha-Syn mutant. The acceleration of alpha-Syn aggregation by the homologous peptides is under a sequence-specific manner. The interplay between the GAV peptide and the core regions in alpha-Syn may accelerate the aggregation process and stabilize the fibrils. This finding provides clues for developing peptide mimics that could promote transforming the toxic oligomers or protofibrils into the inert mature fibrils.

Inhibition of alpha-synuclein fibrillization by dopamine analogs via reaction with the amino groups of alpha-synuclein. Implication for dopaminergic neurodegeneration

Fibrillization of alpha-synuclein (alpha-Syn) is closely associated with the formation of Lewy bodies in neurons and dopamine (DA) is a potent inhibitor for the process, which is implicated in the causative pathogenesis of Parkinson's disease (PD). To elucidate any molecular mechanism that may have biological relevance, we tested the inhibitory abilities of DA and several analogs including chemically synthetic and natural polyphenols in vitro. The MS and NMR characterizations strongly demonstrate that DA and its analogs inhibit alpha-Syn fibrillization by a mechanism where the oxidation products (quinones) of DA analogs react with the amino groups of alpha-Syn chain, generating alpha-Syn-quinone adducts. It is likely that the amino groups of alpha-Syn undergo nucleophilic attack on the quinone moiety of DA analogs to form imino bonds. The covalently cross-linked alpha-Syn adducts by DA are primarily large molecular mass oligomers, while those by catechol and p-benzoquinone (or hydroquinone) are largely monomers or dimers. The DA quinoprotein retains the same cytotoxicity as the intact alpha-Syn, suggesting that the oligomeric intermediates are the major elements that are toxic to the neuronal cells. This finding implies that the reaction of alpha-Syn with DA is relevant to the selective dopaminergic loss in PD.

An Unstructured Region is Required by GAV Homologue for the Fibrillization of Host Proteins

Accumulating evidence shows that some amyloidogenic proteins contain core sequences, which are critical for their fibrillization. Core sequences of alpha-synuclein, beta-amyloid peptide and prion protein usually reside in their unfolded regions and share a conserved consensus (VGGAVVAGV) designated as GAV homologue. Here we investigate the role of unfolded regions in fibrillization after GAV homologue is attached to the C-terminus or inserted into the loop regions of different host proteins, namely alpha -Syn1-65, gamma-synuclein, E. coli thioredoxin and immunoglobulin G binding B1 domain of streptococcal protein G. The results imply that an unstructured region is required by GAV homologue for the fibrillization of host proteins. A number of amyloidogenic proteins with core sequences located in unstructured regions are summarized and discussed in details. The finding may provide further insight into the elucidating of the molecular mechanism underlying the fibrillization of alpha-Syn, Abeta and PrP as well as other amyloidogenic proteins.

Structural Evidence for α-Synuclein Fibrils Using in Situ Atomic Force Microscopy

Human α-synuclein is a presynaptic terminal protein and can form insoluble fibrils that are believed to play an important role in the pathogenesis of several neurodegenerative diseases such as Parkinson's disease, dementia with Lewy bodies and Lewy body variant of Alzheimer's disease. In this paper, in situ atomic force microscopy has been used to study the structural properties of α-synuclein fibrils in solution using two different atomic force microscopy imaging modes: tapping mode and contact mode. In the in situ contact mode atomic force microscopy experiments α-synuclein fibrils quickly broke into fragments, and a similar phenomenon was found using tapping mode atomic force microscopy in which α-synuclein fibrils were incubated with guanidine hydrochloride (0.6 M). The α-synuclein fibrils kept their original filamentous topography for over 1 h in the in situ tapping mode atomic force microscopy experiments. The present results provide indirect evidence on how β-sheets assemble into α-synuclein fibrils on a nanometer scale.

Structural evidence for alpha-synuclein fibrils using in situ atomic force microscopy

Human alpha-synuclein is a presynaptic terminal protein and can form insoluble fibrils that are believed to play an important role in the pathogenesis of several neurodegenerative diseases such as Parkinson's disease, dementia with Lewy bodies and Lewy body variant of Alzheimer's disease. In this paper, in situ atomic force microscopy has been used to study the structural properties of alpha-synuclein fibrils in solution using two different atomic force microscopy imaging modes: tapping mode and contact mode. In the in situ contact mode atomic force microscopy experiments alpha-synuclein fibrils quickly broke into fragments, and a similar phenomenon was found using tapping mode atomic force microscopy in which alpha-synuclein fibrils were incubated with guanidine hydrochloride (0.6 M). The alpha-synuclein fibrils kept their original filamentous topography for over 1 h in the in situ tapping mode atomic force microscopy experiments. The present results provide indirect evidence on how beta-sheets assemble into alpha-synuclein fibrils on a nanometer scale.

DNA-binding and photocleavage studies of cobalt(III) mixed-polypyridyl complexes containing 2-(2-chloro-5-nitrophenyl)imidazo [4,5-f][1,10]phenanthroline

The ligand 2-(2-chloro-5-nitrophenyl)imidazo[4,5-f][1,10]phenanthroline(CNOIP) and its complexes [Co(bpy)(2)(CNOIP)](3+) (1) and [Co(phen)(2)(CNOIP)](3+) (2) (bpy=2,2'-bipyridine; phen=1,10-phenanthroline) have been synthesized and characterized. Binding of the two complexes with calf thymus DNA has been investigated by spectroscopic methods, cyclic voltammetry, viscosity, and electrophoresis measurements. The experimental results indicate that both complexes bind to DNA through an intercalative mode. In comparison with their parent complexes containing PIP ligand (PIP=2-phenylimidazo[4,5-f][1,10]phenanthroline), the introduction of NO(2) and Cl groups to the PIP ligand decreased the binding affinity of complexes 1 and 2 to CT DNA. Both complexes have also been found to promote the photocleavage of plasmid pBR 322 DNA, the hydroxyl radical (OH*) is suggested to be the reactive species responsible for the cleavage.

Trans-(DL-isoleucinato-N,O)[tris(2-aminoethyl)amine-kappa(4)N]cobalt(III)diperchlorate

The racemic title compound, trans-[N,N-bis(2-aminoethyl)-1,2-ethanediamine-kappa(4)N](DL-isoleucinato-N,O)cobalt(III) diperchlorate, [Co(C(6)H(18)N(4))(C(6)H(12)NO(2))](ClO(4))(2), crystallizes in the enantiomorphous space group P2(1)2(1)2(1) with Z = 12 (Z' = 3). Each of the three cations in the asymmetric unit represents a different chirality of the isoleucine ligand; two of them are R (or D) and the third is the S (or L) enantiomer. The mixture crystallizes in a so-called unbalanced crystallization, in which the cations adopt a chiral array of composition RRS or SSR, depending on the crystal selected for data collection.

The design of new molecular "light switches" for DNA

Two novel ruthenium(II) complexes, [Ru(pztp)2(phen)](ClO4)2 and [Ru(pztp)2(bpy)] (ClO4)2, have been synthesized and characterized by UV/Vis and 1H NMR spectroscopies and mass spectrometry. The MeCN solutions of both complexes display fluorescence that was found to be highly sensitive to the presence and concentration of water. The complexes behave like a "light switch" for DNA in that they do not luminesce in water but were "turned on" in the presence of DNA and show emission enhancement with the increase of DNA concentration. Their DNA binding behavior was also studied by absorption spectroscopy and viscosity measurements, which suggest that the DNA-complex interaction involves intercalation of the metal-bound pztp ligand into the base pairs of duplex DNA.

Effects of metal ions on simultaneous production of glucose oxidase and catalase by Aspergillus niger

The effects of various metal ions on the simultaneous production of glucose oxidase and catalase by Aspergillus niger were investigated. Calcium carbonate induced synthesis of both enzymes. The induction of calcium carbonate was accompanied by a metabolic shift from the glycolytic pathway (EMP, Embden-Meyerhof-Parnas) to direct oxidation of glucose by glucose oxidase. The time course of the biosynthesis of both enzymes is reported. The logistic model was in good agreement with the experimental growth results. The production of both enzymes was growth-associated. Finally, a model of growth and product formation was also proposed.

DNA-binding and photocleavage studies of cobalt(III) polypyridyl complexes:

Two complexes of [Co(phen)2IP]3+ (IP=imidazo[4,5-f][l,10]phenanthroline) and [Co(phen)2PIP]3+ (PIP=2-phenylimidazo[4,5-f][1,10]phenanthroline) have been synthesized and characterized by UV/VIS, IR, EA and mass spectra. The binding of the two complexes with calf thymus DNA has been investigated by absorption spectroscopy, cyclic voltammetry, viscosity measurements and DNA cleavage assay. The spectroscopic studies together with cyclic voltammetry and viscosity experiments support that both of the complexes bind to CT DNA by intercalation via IP or PIP into the base pairs of DNA. [Co(phen)2PIP]3+ binds more avidly to CT DNA than [Co(phen)2IP]3+, which is consistent with the extended planar and pi system of PIP. Noticeably, the two complexes have been found to be efficient photosensitisers for strand scissions in plasmid DNA.

Synthesis, characterization and DNA binding of ruthenium(II) complexes containing the atatp ligand

Acenaphtheno[1,2-b]-1,4,8,9-tetraazatriphenylene (atatp) and its complexes [Ru(L)2atatp](ClO4)2 x nH2O (L = 2,2'-bipyridine (bpy), n=2 (1); 1,10-phenanthroline (phen), n=2 (2); and 2,9-dimethyl-1,10-phenanthroline (dmp), n=1 (3)) have been synthesized and characterized by elemental analyses and 1H NMR. The spectral and electrochemical properties of these complexes are also examined. Complexes 1 and 2 display bright luminescence in acetonitrile but very weak luminescence in water solution. However, complex 3 is not luminescent in either solvent. The interaction of the complexes with calf thymus DNA (CT-DNA) has been studied by absorption, emission and viscosity measurements. The intrinsic binding constants of complexes 1 and 2 are 7.6 x 10(4) and 8.8 x 10(4) M(-1) respectively. The relatively low affinities of complexes 1 and 2 with DNA may arise from the atatp ligand, indicating that the size and shape of the intercalated ligand have a marked effect on the strength of interaction. Complexes 1 and 2 bind with CT-DNA in an intercalative mode but complex 3 in a non-intercalative one, showing that changing the ancillary ligand affects not only the binding magnitude, but also the binding mode of the interaction.

Enantiomeric ruthenium(II) complexes binding to DNA: binding modes and enantioselectivity

A series of enantiomerically pure polypyridyl ruthenium(II) complexes, delta- and lambda-[Ru(bpy)2 (HPIP)](PF6)2 (delta-1 and lambda-1; bpy=2,2'-bipyridine, HPIP = 2-(2-hydroxyphenyl)imidazo[4,5-f][1,10]phenanthroline), delta and lambda-[Ru(bpy)2(HNAIP)](PF6)2 (delta-2 and lambda-2; HNAIP = 2-(2-hydroxy-1-naphthyl)imidazo[4,5-f][1,10]phenanthroline), delta- and lambda-[Ru(bpy)2 (HNOIP)](PF6)2 (delta-3 and lambda-3; HNOIP = 2-(2-hydroxy-5-nitrophenyl)imidazo[4,5-f][1,10]phenanthroline), and delta- and lambda-[Ru(bpy)2(DPPZ)](PF6)2 (delta-4 and lambda-4; DPPZ= dipyridophenazine), have been synthesized. Binding behavior of these chiral complexes to calf thymus DNA (CT-DNA) has been investigated by electronic absorption, steady-state emission, and circular dichroism spectroscopies, as well as by viscosity measurements and equilibrium dialysis binding studies. Several points came from the results. (1) The DNA-binding properties were distinctly different for the [Ru(bpy)2L]2+ (L=HPIP, HNAIP, HNOIP) series of ruthenium(II) complexes, which indicates that the photophysical behavior of the complexes on binding to DNA can be modulated through ligand design. (2) Different binding rates of individual enantiomers of complexes 1 and 4 to DNA were observed through dialysis experiments. The lambda enantiomer bound more rapidly than the lambda enantiomer and their different intercalative binding geometries were suggested to be responsible. (3) Both delta-2 and lambda-2 bound weakly to CT-DNA; delta-2 may bind through a partial intercalation mode, whereas lambda-2 may bind in the DNA groove. (4) There was no noticeable enantioselectivity for complexes 1, 3, and 4 on binding to CT-DNA. Both of their enantiomers can intercalate into DNA base pairs. It is noted that delta-3 and lambda-3 exhibited almost identical spectral changes on addition of CT-DNA, and a similar binding manner of the isomers to the double helix was proposed.

Synthesis of glucose oxidase and catalase by Aspergillus niger in resting cell culture system

The synthesis of glucose oxidase and catalase by Aspergillus niger was investigated using a resting cell culture system without growth being established. Calcium carbonate induced the synthesis of both enzymes and calcium chloride inhibited it. The optimal pH for the biosynthesis of glucose oxidase and catalase was 6.0 and 5.7, respectively. The effects of other bivalent cations, reductive compounds and metabolic products on enzyme synthesis were also tested. The biosynthesis of glucose oxidase and catalase was promoted by MnCO3, thioglycolic acid, pyroracemic acid and gluconic acid.

Synthesis, characterization and the effect of ligand planarity of [Ru(bpy)2L]2+ on DNA binding affinity

Two structurally related ligands (L) 4,5,9,18-tetraazaphenanthreno[9,10-b] triphenylene (taptp) and 2,3-diphenyl-1,4,8,9-tetraazatriphenylene (dptatp), and their related complexes of [Ru(bpy)2L]2+ have been synthesized and characterized by elemental analyses, 1H NMR and mass spectra. Their electrochemical properties were also examined. Both complexes emit intense luminescence in organic solvent but are quenched in water to different extents. The interactions of the complexes with calf thymus DNA have been investigated by viscosity, absorption, emission and circular dichroism spectra. The intrinsic binding constants of [Ru(bpy)2(taptp)]2+ and [Ru(bpy)2(dptatp)]2+ are 1.7 x 10(5) and 3.8 x 10(4) M-1, respectively. All data indicate that both complexes bind enantioselectively to double-stranded calf thymus DNA via the intercalative mode, with stronger affinity for the fully planar ligand complex of [Ru(bpy)2(taptp)]2+.

Study of the interaction between novel ruthenium(II)-polypyridyl complexes and calf thymus DNA

Four new complexes L2RuL'2+, where L = 2,2'-bipyridine (bpy) and 1,10-phenanthroline (phen), L' are Schiff bases or phenylhydrazones derived from 4,5-diazafluoren-9-one (AFO), were prepared. They were characterized by elemental analyses, absorption, IR, and emission spectra. The binding of these complexes to calf thymus DNA has been investigated by absorption, circular dichroism spectroscopy, and viscosity measurement. The experimental results show that the complexes bind to calf thymus DNA by three kinds of binding modes, respectively-electrostatic mode, nonintercalative binding mode, and intercalative binding mode.

[HLA-DQ gene and susceptibility of insulin dependent diabetes mellitus in Chinese population]

Trans-racial analysis of disease association has improved mapping of MHC-linked susceptibility to insulin dependent diabetes mellitus (IDDM). In this study, the contribution of the HLA class II DQA1 and DQB1 genes was investigated. Nine DQA1 and 10 DQB1 sequence-specific oligonucleotide gene probing in 49 IDDM and 48 control subjects from Beijing showed that DQA1-A4 alleles was positively associated with the disease (RR = 11.7, Pc < 0.02) as was the Asp57 negative homozygotes of DQB1 gene (P < 0.01, RR = 5.3), and that Asp57 positive homozygote of DQB1 gene conferred protection against IDDM (P < 0.025, RR = 0.38). Compared with trans-racial study, the decrease of Asp57 negative homozygote frequence and increase of Asp57 positive homozygote frequence in Chinese population may contribute to the low incidence of IDDM.