The magnetocaloric effect and critical behaviour of the Mn(0.94)Ti(0.06)CoGe alloy

Structural, magnetic and magnetocaloric properties of the Mn(0.94)Ti(0.06)CoGe alloy have been investigated using x-ray diffraction, DC magnetization and neutron diffraction measurements. Two phase transitions have been detected, at T(str) = 235 K and T(C) = 270 K. A giant magnetocaloric effect has been obtained at around T(str) associated with a structural phase transition from the low temperature orthorhombic TiNiSi-type structure to the high temperature hexagonal Ni(2)In-type structure, which is confirmed by neutron study. In the vicinity of the structural transition, at T(str), the magnetic entropy change, -ΔS(M) reached a maximum value of 14.8 J kg(-1) K(-1) under a magnetic field of 5 T, which is much higher than that previously reported for the parent compound MnCoGe. To investigate the nature of the magnetic phase transition around T(C) = 270 K from the ferromagnetic to the paramagnetic state, we performed a detailed critical exponent study. The critical components γ, β and δ determined using the Kouvel-Fisher method, the modified Arrott plot and the critical isotherm analysis agree well. The values deduced for the critical exponents are close to the theoretical prediction from the mean-field model, indicating that the magnetic interactions are long range. On the basis of these critical exponents, the magnetization, field and temperature data around T(C) collapse onto two curves obeying the single scaling equation M(H,ε) = ε(β)f ± (H/ε(β+γ)).

Synthesis and electrochemical properties of Sn-SnO2/C nanocomposite

A Sn-SnO2/C nanocomposite was synthesized using the electrospinning method. Thermal analysis was used to determine the content range of Sn and SnO2 in the composite. The composite was characterized by X-ray diffraction, and the particle size and shape in the Sn-SnO2/C composite were determined by scanning and transmission electron microscopy. The results show that the Sn-SnO2/C composite takes on a nanofiber morphology, with the diameters of the nanofibers distributed from 50 to 200 nm. The electrochemical properties of the Sn-SnO2/C composite were also investigated. The Sn-SnO2/C composite as an electrode material has both higher reversible capacity (887 mAh x g(-1)) and good cycling performance in lithium-anode cells working at room temperature in a 3.0 V to 0.01 V potential window. The Sn-SnO2/C composite could retain a discharge capacity of 546 mAh/g after 30 cycles. The outstanding electrochemical properties of the Sn-SnO2/C composite obtained by this method make it possible for this composite to be used as a promising anode material.

Assessment of the CKD-EPI equation to estimate glomerular filtration rate in adults from a Chinese CKD population

The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation was introduced to estimate glomerular filtration rate (GFR) in chronic kidney disease (CKD) patients based on serum creatinine. The CKD-EPI equation shows better accuracy compared with the current gold standard equation, the Modification of Diet in Renal Disease (MDRD) equation, but it has not been externally validated in Chinese patients. This study compared the CKD-EPI equation with the original MDRD equation and two Chinese MDRD-based equations for estimating GFR in 200 Chinese CKD patients. The (99m)Tc-diethylenetriamine penta-acetate ((99m)Tc-DTPA) method was used to determine actual GFR. The CKD-EPI equation produced GFR estimates that were more consistent with the (99m)Tc-DTPA GFR than did the MDRD equations. The precision and accuracy of the CKD-EPI equation were significantly higher than those of the MDRD equations. In conclusion, the CKD-EPI equation was superior to the existing MDRD equations in terms of estimating GFR and we recommend its clinical use in Chinese CKD patients.

First Report of Twig Canker on Peach Caused by Phomopsis amygdali in China

During May and June of 2009, canker and twig dieback were observed with 30 to 40% incidence in trees in one peach orchard in Nanhui of Shanghai (cv. YuLu juicy peach) and one orchard (cv. JingXiu yellow peach) in Jiaxin of Zhejiang Province, China. Cankers were generally centrally positioned on the nodes at the base of shoots with sunken, reddish brown/tan-to-silver symptoms. Blight was also observed on a few shoots (1). Five samples were collected from each orchard and isolations were conducted on potato sucrose agar (PSA). Ten isolates were obtained and all had white mycelia on PSA. Black pycnidia, formed in culture, produced two types of conidia: hyaline, fusiform alpha conidia and hyaline, string-like beta conidia. Alpha conidia varied from 5.0 to 6.3 × 1.5 to 2.5 μm and beta conidia ranged from 20 to 25 × 1.2 to 1.5 μm. Morphological characteristics suggested the identity of the fungal isolates to be Phomopsis amygdali. To confirm pathogenicity, an inoculum suspension was made from one isolate (10⁶ conidia/ml) and was sprayed until runoff onto five twigs with buds. Inoculated twigs were maintained at 26°C and 100% relative humidity in a growth chamber with a 12-h period of fluorescent light daily. Twigs inoculated with sterilized water were included as noninoculated controls. After 4 days, dark brown lesions appeared around buds on inoculated twigs. No symptoms were observed on the control twigs. Constriction cankers were reproduced and P. amygdali was reisolated from the lesions. To confirm the identity of the pathogen, total genomic DNA was extracted with the cetyltrimethylammoniumbromide (CTAB) method from the mycelia of two isolates from YuLu juicy peach and Jinxiu yellow peach (2). PCR was performed with universal primers ITS1 (5'-TCCGTAGGTGAACCTGCGG-3') and ITS4 (5'-TCCTCCGCTTATTGATATGC-3') to amplify a DNA fragment of approximately 550 bp. The PCR products were purified and sequenced in both directions (Sangon Biotech (Shanghai) Co., Ltd., China). The sequences (GenBank Accession Nos. HQ632013 and HQ632014) shared 98.9% identity with each other (MegAlign software; DNASTAR, Madison, WI). A comparison of these two sequences with those in GenBank showed that the sequences had the highest nucleotide similarity (99%) with P. amygdali isolate FAU1052 from peach in the southeastern United States (Accession No. AF102998). To our knowledge, this is the first report of P. amygdali causing twig canker on peach in China and will provide useful information for developing effective control strategies. References: (1) D. F. Farr et al. Mycologia 91:1008, 1999. (2) M. A. Saghai-Maroof et al. Proc. Natl. Acad. Sci. USA. 81:8014, 1984.

Critical magnetic transition in TbNi2Mn--magnetization and Mössbauer spectroscopy

The structural and magnetic properties of the TbNi(2)Mn(x) series (0.9 ≤ x ≤ 1.10) have been investigated using x-ray diffraction, field- and temperature-dependent AC magnetic susceptibility, DC magnetization (5-340 K; 0-5 T) and (57)Fe Mössbauer spectroscopy (5-300 K). TbNi(2)Mn(x) crystallizes in the MgCu(2)-type structure (space group Fd3m). The additional contributions to the magnetic energy terms from transition-metal-transition-metal interactions (T-T) and rare-earth-transition-metal interactions (R-T) in RNi(2)Mn compounds contribute to their increased magnetic ordering temperatures compared with RNi(2) and RMn(2). Both the lattice constant a and the Curie temperature T(C) exhibit maximal values at the x = 1 composition indicating strong magnetostructural coupling. Analyses of the AC magnetic susceptibility and DC magnetization data of TbNi(2)Mn around the Curie temperature T(C) = 147 K confirm that the magnetic transition is second order with critical exponents β = 0.77 ± 0.12, γ = 1.09 ± 0.07 and δ = 2.51 ± 0.06. These exponents establish that the magnetic interactions in TbNi(2)Mn are long range despite mixed occupancies of Tb and Mn atoms at the 8a site and vacancies. The magnetic entropy - ΔS(M) around T(C) is proportional to (μ(0)H/T(C))(2/3) in agreement with the critical magnetic analyses. The Mössbauer spectra above T(C) are fitted by two sub-spectra in agreement with refinement of the x-ray data while below T(C) three sub-spectra are required to represent the three inequivalent local magnetic environments.

First Report of Tomato yellow leaf curl virus Infecting Cowpea in China

Tomato yellow leaf curl virus (TYLCV) is a devastating pathogen of tomato that causes significant yield losses in many tropical and subtropical regions (1). In China, this virus was first found in 2006 on tomato in Shanghai (2). In October 2008, chlorotic yellow leaves of cowpea (Vigna sinensis) were observed in Qingpu, Shanghai, China with 15 to 20% incidence in plants in high tunnels. Large populations of whiteflies were observed in association with the diseased cowpea. The disease agent was transmitted to cowpea (and tomato) by whiteflies, which resulted in chlorotic yellow leaves on cowpea (yellow leaf curl symptoms on tomato) that were identical to those observed in the field. On the basis of the suspected insect vector, symptomology, and severe epidemics of tomato yellow leaf curl disease (TYLCD) in Shanghai in recent years, Tomato yellow leaf curl virus was suspected as the causal agent. Total DNA was extracted from four symptomatic cowpea samples. PCR was performed with specific primers V416 (5'-CAAGGCACAAACAAGCGACG-3') and C1287 (5'-CTCAACTTCCGAATTTGGACGAC-3') to amplify a 872-bp DNA fragment of the viral coat protein (CP) gene and an amplicon of the expected size was obtained in all four samples but not from healthy leaf samples. The PCR products were sequenced and the sequences were identical among samples. Primers TYLCV-F (5'-CAGGAGGCAGCCAAGTATGAG-3') and TYLCV-R (5'-ACTAATGCCTGTTCYTTCATTCC-3') (Y = C or T/U) were designed on the basis of the sequence (Accession No. HM804856) and reported (Accession No. FM163463) CP gene to amplify the full-length viral DNA of cowpea isolate (CN:SH:Cowpea:08). The sequence was determined to be 2,781 nucleotides long (Accession No. GU434143). A comparison of the sequence with those in GenBank shows that the cowpea isolate has the highest nucleotide sequence identity (99%) with TYLCV isolate XH2 from tomato in Xinghua, Jiangsu, China (Accession No. GU111505). To our knowledge, this is the first report of TYLCV infecting cowpea in China and also the first report in the world. References: (1) H. Czosnek and H. Laterrot. Arch. Virol. 142:1391, 1997. (2) J. B. Wu et al. Plant Dis. 90:1359, 2006.

First Report of Cucurbit chlorotic yellows virus Infecting Melon in China

In October 2007, symptoms of chlorosis on the upper leaves and a bright yellow color on the lower leaves were observed sporadically on hami melon (Cucumis melo cv. Xuelihong) in a high tunnel in Nanhui of Shanghai, China. Disease progresses from initial mottling of leaves into leaves that are completely yellow with the veins remaining green. The oldest leaves develop symptoms first, so these leaves have a pronounced even yellow color. In October 2009, these symptoms were found in all melons produced in the suburbs of Shanghai. These symptoms were similar to those caused by Cucurbit yellow stunting disorder virus (CYSDV) and Cucurbit chlorotic yellows virus (CCYV) (1-3). Twelve samples from symptomatic melons were collected in the Jiading, Nanhui, Fengxian, and Chongming districts of Shanghai for virus diagnosis. Large populations of whiteflies were observed in association with the diseased cucurbit crops. Total RNA was extracted with Trizol reagents (Invitrogen, Carlsbad, CA). We used random primers (9-mer) for reverse transcription-PCR. Extracts were for CYSDV using specific primers CYSDV-CP-F (5'-ATGGCGAGTTCGAGTGAGAA-3') and CYSDV-CP-R (5'-TCAATTACCACAGCCACCTG-3') to amplify a 756-bp fragment of coat protein gene and CCYV using specific primers CCYV-HSP-F1 (5'-TGCGTATGTCAATGGTGTTATG-3') and CCYV-HSP-R1 (5'-ATCCTTCGCAGTGAAAAACC-3') to amplify a 462-bp fragment of the HSP gene (1). CYSDV was not found in all samples. The expected 462-bp target fragment of CCYV was obtained in all samples but not from any of the healthy controls. All the 462-bp PCR products were cloned to pGEM-T vector (Promega, Madison, WI) and sequenced. All sequences obtained were homologous. A comparison of the submitted sequence (GenBank Accession No. HQ148667) with those in GenBank showed that the sequence had 100% nucleotide identity to the Hsp70h sequences of (CCYV) isolates from Japan (Accession Nos. AB523789 and AB457591) (1,4), Taiwan (Accession No. HM120250) (2), and mainland of China (Accession Nos. GU721105, GU721108, and GU721110). CCYV is a new member of the genus Crinivirus, first discovered in Japan in 2004 (4) and reported in Taiwan in 2009 (2). To our knowledge, this is the first report of CCYV on melon in China. References: (1) Y. Gyoutoku et al. Jpn. J. Phytopathol. 75:109, 2009. (2) L.-H. Huang et al. Plant Dis. 94:1168, 2010. (3) L. Z. Liu et al. Plant Dis.94:485, 2010. (4) M. Okuda et al. Phytopathology 100:560, 2010.

A truncated retrotransposon disrupts the GRM1 coding sequence in Coton de Tulear dogs with Bandera's neonatal ataxia

BACKGROUND

Bandera's neonatal ataxia (BNAt) is an autosomal recessive cerebellar ataxia that affects members of the Coton de Tulear dog breed.

OBJECTIVE

To identify the mutation that causes BNAt.

ANIMALS

The study involved DNA from 112 Cotons de Tulear (including 15 puppies with signs of BNAt) and 87 DNA samples from dogs of 12 other breeds.

METHODS

The BNAt locus was mapped with a genome-wide association study (GWAS). The coding exons of positional candidate gene GRM1, which encodes metabotropic glutamate receptor 1, were polymerase chain reaction (PCR)-amplified and resequenced. A 3-primer PCR assay was used to genotype individual dogs for a truncated retrotransposon inserted into exon 8 of GRM1.

RESULTS

The GWAS indicated that the BNAt locus was in a canine chromosome 1 region that contained candidate gene GRM1. Resequencing this gene from BNAt-affected puppies indicated that exon 8 was interrupted by the insertion of a 5'-truncated retrotransposon. All 15 BNAt-affected puppies were homozygous for the insert, whereas all other Cotons de Tulear were heterozygotes (n = 43) or homozygous (n = 54) for the ancestral allele. None of the 87 dogs from 12 other breeds had the insertion allele.

CONCLUSIONS AND CLINICAL IMPORTANCE

BNAt is caused by a retrotransposon inserted into exon 8 of GRM1. A DNA test for the GRM1 retrotransposon insert can be used for genetic counseling and to confirm the diagnosis of BNAt.

Stem cells and hepatic cirrhosis

Hepatic cirrhosis is defined as the histological development of regenerative nodules surrounded by fibrous bands in response to chronic liver injury, which leads to portal hypertension and end-stage liver disease. The majority of patients with hepatic cirrhosis die from life-threatening complications at early age. Liver transplantation has been the most effective treatment for patients with hepatic cirrhosis. Since liver transplantation is critically limited by the shortage of available donor livers, searching for an effective alternative therapy has attracted great interest in preclinical studies. The encouraging advances in stem cell research have paved the way towards the treatment of the end-stage of chronic liver disease. In view of the pathogenic fundamentals of hepatic cirrhosis, stem cell-based treatment should be aimed to complement or replace damaged liver cells and to correct the imbalanced extracellular matrix regeneration/degradation. This review is intended to describe the characteristics and therapeutic potential of various liver repair-related stem cells, including hepatocytes, liver progenitor cells, hematopoietic stem cells, mesenchymal stem cells, embryonic stem cells and induced pluripotent stem cells. Since autologous adult stem cells have the least number of obstacles for clinical application, their potential interventions on cirrhosis are especially illustrated in terms of the cellular and molecular mechanisms of hepatic fibrogenesis.

Molecular alterations of the IDH1 gene in AML: a Children's Oncology Group and Southwest Oncology Group study

Recent whole-genome sequencing efforts led to the identification of IDH1^R132 mutations in AML patients. We studied the prevalence and clinical implications of IDH1 genomic alterations in pediatric and adult AML. Diagnostic DNA from 531 AML patients treated on Children’s Oncology Group trial COG-AAML03P1 (N=257), and Southwest Oncology Group trials SWOG-9031, SWOG-9333, and SWOG-9500 (N=274), were tested for IDH1 mutations. Codon R132 mutations were absent in the pediatric cohort, but were found in 12/274 adult patients (4.4%, 95% CI 2.3-7.5%). IDH1^R132 mutations occurred most commonly in patients with normal karyotype, and those with FLT3/ITD and NPMc mutations. Patients with IDH1^R132 mutations trended towards higher median diagnostic WBC counts (59.2 × 10⁹/L vs. 29.1 × 10⁹/L, P=0.19) than those without mutations, but the two groups did not differ significantly in age, bone marrow blast percentage, overall survival, or relapse-free survival. Eleven patients (2.1%) harbored a novel V71I sequence alteration, which was found to be a germline polymorphism. IDH1 mutations were not detected in pediatric AML, and are uncommon in adult AML.

Magnetic scattering effects in two-band superconductor: the ferromagnetic dopants in MgB₂

This paper demonstrates the magnetic scattering effects on the electron-phonon interaction in two-band superconductors based on the transition-metal-doped MgB₂ to clarify the effects of magnetic dopants on multi-band superconductivity. The phonon properties of polycrystalline Mg(1-x)M(x)B₂ (M = Fe, Ni and Co), with x up to 0.05, were studied, with the investigation based on the normal state Raman spectra, especially the variation of the E(2g) mode. The magnetic scattering effect of Fe is much weaker than that of Mn in MgB₂, while it is stronger than that of Ni. The weak magnetic scattering effects are responsible for the superconducting behaviors of Mg(1 - x)Fe(x)B₂ and Mg(1 - x)Ni(x)B₂. Co shows almost no magnetic scattering effects on the superconductivity, while the depression of the critical temperature, T(c), in Mg(1 - x)Co(x)B₂ is attributed to the phonon behavior and is independent of the ferromagnetic nature of cobalt.

Magnetic phase transitions in Pr(1-x)Lu(x)Mn(2)Ge(2) compounds

The effects of replacing Pr by Lu on the magnetic behaviour and structures of Pr(1-x)Lu(x)Mn(2)Ge(2) (x = 0.2,x = 0.4) have been investigated using x-ray diffraction, Mössbauer spectroscopy, magnetization and neutron diffraction measurements. The substitution of Lu for Pr leads to a decrease in the lattice constants a, c and the unit cell volume V at room temperature with this contraction of the unit cell resulting in modifications of the Pr(1-x)Lu(x)Mn(2)Ge(2) magnetic structures. Four and five magnetic phase transitions-linked primarily with temperature driven changes in the intralayer Mn-Mn separation distances-have been detected within the temperature range 4.5-550 K for Pr(0.8)Lu(0.2)Mn(2)Ge(2) and Pr(0.6)Lu(0.4)Mn(2)Ge(2), respectively, with re-entrant ferromagnetism being detected around T(C)(Pr)∼31 K for Pr(0.6)Lu(0.4)Mn(2)Ge(2). It was found that T(C)(inter) and T(C)(Pr) increase with increasing applied field while T(N)(inter) decreases for Pr(0.6)Lu(0.4)Mn(2)Ge(2), indicating that the canted antiferromagnetic AFmc region contracts with increasing field. The Debye temperatures for Pr(1-x)Lu(x)Mn(2)Ge(2) with x = 0.2 and 0.4 were evaluated as θ(D) = 320 ± 40 K and θ(D) = 400 ± 20 K respectively from the temperature dependence of the average isomer shift. The magnetic structures of both compounds have been determined by means of neutron diffraction measurements over the temperature range 3-300 K with formation of the Fmi magnetic state below T(c/c) = 192 K for Pr(0.8)Lu(0.2)Mn(2)Ge(2) and the occurrence of re-entrant ferromagnetism below T(C)(Pr) = 31 K for Pr(0.6)Lu(0.4)Mn(2)Ge(2) being confirmed.

Determination of milk and blood concentrations of lipopolysaccharide-binding protein in cows with naturally acquired subclinical and clinical mastitis

Blood and milk concentrations of the acute phase protein lipopolysaccharide-binding protein (LBP) were evaluated in cows with naturally occurring mastitis. Blood and milk samples were collected from 101 clinically healthy dairy cows and 17 dairy cows diagnosed with clinical mastitis, and the LBP concentrations of the samples were measured by an ELISA. Concentrations of LBP were greater in the blood and milk of cows with clinical mastitis than in those with healthy quarters. Concentrations of LBP also differed between uninfected and subclinically infected quarters with low somatic cell count. Blood concentrations of LBP in cows with subclinical intramammary infections could not be differentiated from those of cows with all healthy quarters. Together, these data demonstrate that increased blood and milk concentrations of LBP can be detected in dairy cows with naturally acquired intramammary infections that cause clinical mastitis.

Endogenously expressed truncated P2X7 receptor lacking the C-terminus is preferentially upregulated in epithelial cancer cells and fails to mediate ligand-induced pore formation and apoptosis

A truncated naturally occurring variant of the human purinergic receptor P2X7 (P2X7-R) was found in human cancer cervical cells. The novel protein consists of 258 amino acids, and compared to the wild-type P2X7-R it lacks the entire intracellular carboxy terminus, the second transmembrane domain, and the distal third of the extracellular loop. The truncated P2X7-R failed to form pores and mediate apoptosis, and it interacted with the wild-type P2X7-R in a manner suggesting auto-hetero-oligomerization. In contrast to cancer cells the novel truncated P2X7-R was expressed relatively little in normal cervical cells. These data raise the possibility that coexpression of the truncated form could block P2X7 mediated apoptosis and promote uncontrolled growth of cells.

Construction and Characterization of a cDNA Library from Liver Tissue of Chinese Banna Minipig Inbred Line

A xenograft that performs efficient functions is an essential premise for successful xenotransplantation. Our early study indicated that Chinese Banna minipig inbred line (BMI) was an ideal xenograft donor. However, the activities of some proteins synthesized by the BMI liver are different from the human, which could lead to functional disorders in coagulation, fibrinolysis, and anticoagulation after liver xenotransplantation. Therefore, it is important to investigate the genetic background of protein incompatibility and to provide new strategies for gene manipulation. In this study we constructed a cDNA expression library using BMI liver tissue to obtain an understanding of nucleic acid and protein differences between the two species. We extracted total RNA and purified mRNA of the liver tissue from one of the sixteenth inbred generation of BMI/JS 151 substrain. After double-strand cDNA synthesis, we fractionated it on a CHROMA APIN-400 column; ligated the longer than 500bp cDNA into a ZAP Express Vector; and performed a lambda: phage packaging reaction, library amplification, and titer. We randomly picked 12 plaques and tested the length of inserts. The titers of the primary and amplified libraries were 1.0 x 10(6) pfu/mL and 5.0 x 10(9) pfu/mL, respectively. The percentages of recombinants were 97.0% in the primary library and 98.0% in the amplified library. The lengths of most inserts were between 750 bp and 2.0 kb. Thus, we successfully constructed a cDNA expression library from BMI liver tissue. Using the library, we hope to get a full-length cDNA of some important genes and conduct further studies on porcine liver function in xenotransplantation.

Study of hepatic function matching between banna minipig inbred and humans

As a unique inbred pig Banna minipig inbred (BMI) is potentially suitable for pig-to-human xenotransplantation due to its clear genetic background and minor interindividual differences. Previous studies of BMI have focused on immunological barriers between BMI and humans. However, a comparison of liver function between donor animals and humans is an essential premise for successful xenotransplantation. In this study, we investigated routine hepatic functions, protein electrophoresis, and drug metabolism to compare capacity of liver synthesis, metabolism, and drainage between BMI and humans. The results showed no significant differences in the concentrations of albumin and globulin synthesized in the liver (alpha1, alpha2, and beta-globulin). Serum enzyme activities in BMI were higher than those in humans, and levels of total bilirubin and direct-reacting bilirubin of BMI were lower than those of humans. In BMI, the clearance of antipyrine, a widely used model drug to study hepatic drug metabolism, was 16 times greater than that by humans, with a mean residual time of antipyrine in BMI, one-tenth of that in human. These findings suggested that BMI livers are similar to humans in albumin and alpha, beta-globulin synthesis, but stronger in bilirubin elimination, enzyme activity, and drug metabolism. BMI livers may have stronger functions compared with those of humans. No incompatibility was identified in hepatic function between BMI and humans.

Activation of human coagulation system by liver-derived clotting factors of banna minipig inbred line

The liver synthesizes most of the coagulation factors that play a major role in arresting hemorrhage. Matching hepatic coagulation factors is an important premise in successful xenotransplantation. As a unique inbred pig, the Banna minipig inbred (BMI) animals have a huge potential value for pig-to-human xenotransplantation, due to its clear genetic background and tiny interindividual differences. Whether the coagulation factors synthesized by porcine liver can trigger human clotting pathways has not been reported. This study focused on the activities of BMI coagulant factors synthesized exclusively by the liver to activate human clotting pathways. In these experiments we prepared coagulant factors II, V, VII, X, and XII synthesized exclusively by liver from BMI and humans. The factors were used in common correction tests, added to the corresponding factor-deficient human plasma to determine prothrombin times or activated partial thromboplastin time, thereby calculating BMI and human coagulant factor activities. BMI clotting factors XII, VII, and X triggered human intrinsic, extrinsic, and common pathways, respectively. BMI clotting factors II, V, VII, X, and XII activities were 3.2-, 3.7-, 4.7-, 2.9-, and 4.5-fold as potent as those from humans.

Study of renal function matching between banna minipig inbred line and human

Pigs have been thought to be ideal candidates for xenotransplant donors. However besides the immunological barrier, physiological and pharmacokinetic comparabilities of kidney function between donor animals and humans are important factors for successful xenotransplantation. As a unique large inbred animal, Banna Minipig Inbred (BMI) has been reported to be a potential large animal suitable for xenotransplantation. However, its physical and pharmacokinetic compatibilities with humans have not been documented. The purpose of this investigation was to measure renal routine function, glomerular filtration rate (GFR), renal blood flow (ERPF), and drug metabolism to evaluate comparability to humans. The results suggested that the renal function of BMI was similar to that of humans to eliminate nonprotein nitrogenous end products of metabolism. Pharmacokinetics of p-aminohippurate (PAH) and inulin--the most widely used methods to assess ERPF and GFR--showed that BMI showed lower values than humans for GFR, but similar function to humans in ERPF. The pharmacokinetics of cefazolin; a widely used model drug to study kidney drug metabolizing capacity, showed greater overall renal drug elimination of BMI than of humans. These results suggested that BMI did show comparable data to human renal function.

Comparison of methods for the determination of K(L)aO2 for respirometric measurements

The mass transfer coefficient for oxygen in water (K(L)aO2) is an important parameter for respirometric studies. But determination of K(L)aO2 in process conditions is not straightforward, In this paper, two distinct procedures for determining K(L)aO2 in process conditions are outlined and tested. The off-gas method relies on a gas mass balance over a bioreactor while the non-steady state methods rely on analysing DO recovery after perturbation. Various means for inducing perturbation are tested and compared. K(L)aO2 values for a bioreactor are determined by the listed methods. It was found that the off-gas method resulted in the highest K(L)aO2 for the given reactor, while the non-steady state method, whereby perturbation is caused by exogenous activity on acetate, resulted in the lowest K(L)aO2. It is shown that the gas mass balancing technique is robust to unexpected exogenous activity (caused by for example, the oxidation of storage polymers formed or nitrite accumulated), while the non-steady state methods that involve inducing perturbations by exogenous activity appear susceptible to such continued exogenous activity in the DO recovery period.

Capillary electrophoresis-electrospray mass spectrometry for the characterization of high-mannose-type N-glycosylation and differential oxidation in glycoproteins by charge reversal and protease/glycosidase digestion

The characterization of high-mannose-type N-glycosylation by capillary electrophoresis-electrospray mass spectrometry (CE-ESI MS) was described. In addition to the use of a cationic noncovalent capillary coating, strong acidic buffer, and charge reversal to increase the glycoform resolving power, N-glycosidase F (PNGase F) combined with a basic protease and alpha-mannosidase combined with an acidic protease were used to analyze the high-mannose-type N-glycosylation in ribonuclease B (RNase B) and in a novel C-type lectin from the venom of Trimeresurus stejnegeri (TSL). The structures of oligosaccharide, glycosylation sites, and glycoform distributions were determined simultaneously, and the differential oxidation of Met residues in glycopeptides obtained from TSL protease digestion was also characterized successfully by CE-MS/MS. The results showed that the oligosaccharide attached to RNase B has a structure of GlcNAc2Man5 approximately 9, and that attached to TSL has a structure of GlcNAc2Min5 approximately 8. The glycoform distributions in these glycoproteins are quite different, with the GlcNAc2Man5 type predominant in RNase B, and the GlcNAc2Man8 type, in TSL This method may be useful not only for the characterization of glycosylation sites and glycan structures, but also for the determination of the relative abundance of individual glycoforms.

[The prevalence of beta-thalassemia heterozygotes compound alpha-thalassemia in Guangdong district]

OBJECTIVE

To investigate the prevalence of beta-thalassemia (beta-thal) heterozygotes compound alpha-thal in Guangdong area.

METHODS

alpha-thal 1 genes were amplified in 500 beta-thal carriers diagnosed by reverse dot blotting (RDB) using gap-PCR method, alpha-thal 2 genes were detected in 400 of the 500 beta-thal carriers using Southern blotting with alpha-globin DNA probe and restrict endonuclease zymogram analytical method.

RESULTS

Forty three alpha-thal-1(alpha alpha/- -SEA) cases were identified in the 500 beta-thal traits, and 26 alpha-thal 2 including 17 rightward deletion (alpha alpha/- alpha 3.7) and 9 leftward deletion(alpha alpha/-alpha 4.2) cases were identified in the 400 beta-thal traits.

CONCLUSION

The prevalence of beta-thal heterozygote carrying alpha-thal-1 gene was 8.6% and that of beta-thal heterozygote carrying alpha-thal-2 gene was 6.5% (4.2% rightward deletion and 2.2% leftward deletion).

Initiation of polyoma virus origin-dependent DNA replication through STAT5 activation by human granulocyte-macrophage colony-stimulating factor

Several lines of evidence indicate that transcriptional activation is coupled with DNA replication initiation, but the nature of initiation of DNA replication in mammalian cells is unclear. Polyoma virus replicon is an excellent system to analyze the initiation of DNA replication in murine cells because its replication requires an enhancer, and all components of replication machinery, except for DNA helicase large T antigen, are supplied by host cells. This system was used to examine the role of signal transducer and activator of transcription (STAT5) in replication initiation of polyoma replicon in the mouse lymphoid cell line BA/F3. The plasmid with tandem repeats of consensus STAT5 binding sites followed by polyoma replication origin was replicated by stimulation with human granulocyte-macrophage colony-stimulating factor (hGM-CSF) in the presence of polyoma large T antigen in BA/F3 cells. Mutation analysis of the hGM-CSF receptor beta subunit revealed that only the box1 region is essential, and the C-terminal tyrosine residues are dispensable for the activity. Addition of the tyrosine kinase inhibitor genistein suppressed this replication without affecting transcriptional activation of STAT5. Because deletion analysis of STAT5 indicates the importance of the C-terminal transcriptional activation domain of STAT5 for the initiation of replication, the role of this region in the activation of replication was examined with a GAL4-STAT5 fusion protein. GAL4-STAT5 activated replication of the plasmid containing tandem repeats of GAL4 binding sites and polyoma replication origin in BA/F3 cells. Mutation analysis of GAL4-STAT5 indicated that multiple serine residues coordinately have a role in activating replication. This is the first direct evidence indicating the potential involvement of STAT5 in replication.

Identification of differentially expressed proteins between human hepatoma and normal liver cell lines by two-dimensional electrophoresis and liquid chromatography-ion trap mass spectrometry

In the previous study, the proteomes of the human hepatoma cell line BEL-7404 and the normal human liver cell line L-02 were separated by high resolution two-dimensional electrophoresis (2-DE). Image analysis revealed that 99 protein spots showed quantitative and qualitative variations that were significant (P < 0.01) and reproducible. Here we report the identification results of some of these protein spots. Protein spots excised from 2-D gels were subjected to in-gel digestion with trypsin, and the resulting peptides were measured by microbore high performance liquid chromatography - ion trap - mass spectrometry (LC-IT-MS) to obtain the tandem mass (MS/MS) spectra. Twelve protein spots were identified with high confidence using SEQUEST with uninterpreted MS/MS raw data. Besides inosine-5'-monophosphate dehydrogenase 2, heat shock 27 kDa protein, calreticulin and calmodulin, whose expression was elevated in hepatoma cells, glutathione-S-transferase P was identified from hepatoma cells in which its level was 18-fold higher compared to human liver cells. Two spots were identified as the homologs of reticulocalbin for the first time in hepatoma cells and their expression increased compared to liver cells. However, tubulin beta-1 chain and natural killer cell enhancing factor B were downregulated in hepatoma cells. A tumor suppressing serpin, maspin precursor, was identified from one spot whose quantity was much higher in the normal liver cell line. More interestingly, epidermal fatty acid-binding protein (E-FABP) and fatty acid-binding protein, adipocyte-type (A-FABP), were detected in liver cells but not in hepatoma cells. The functional implication of the identified proteins was discussed.

Determination of the disulfide bond pattern of a novel C-type lectin from snake venom by mass spectrometry

The disulfide bond pattern of Trimeresurus stejnegeri lectin (TSL), a new member of the C-type lectin family, was determined by mass spectrometry. Four intrachain disulfide bonds of TSL, Cys(3)-Cys(14), Cys(31)-Cys(131), Cys(38)-Cys(133) and Cys(106)-Cys(123), and two interchain linkages, Cys(2)-Cys(2) and Cys(86)-Cys(86), were determined. Three strategies were used in this work. One intrachain (Cys(106)-Cys(123)) and one interchain (Cys(86)-Cys(86)) disulfide linkages were detected by standard MS methods. The disulfide bonds Cys(2)-Cys(2) and Cys(3)-Cys(14) were analyzed using a modified partial reduction procedure and MS/MS. The last two disulfide bonds were characterized by a MS/MS/MS technique. The strategies developed in this work could be applied more generally to detection of disulfide bond patterns.

Identification of differentially expressed proteins between human hepatoma and normal liver cell lines by two-dimensional electrophoresis and liquid chromatography-ion trap mass spectrometry

In the previous study, the proteomes of the human hepatoma cell line BEL-7404 and the normal human liver cell line L-02 were separated by high resolution two-dimensional electrophoresis (2-DE). Image analysis revealed that 99 protein spots showed quantitative and qualitative variations that were significant (P < 0.01) and reproducible. Here we report the identification results of some of these protein spots. Protein spots excised from 2-D gels were subjected to in-gel digestion with trypsin, and the resulting peptides were measured by microbore high performance liquid chromatography - ion trap - mass spectrometry (LC-IT-MS) to obtain the tandem mass (MS/MS) spectra. Twelve protein spots were identified with high confidence using SEQUEST with uninterpreted MS/MS raw data. Besides inosine-5'-monophosphate dehydrogenase 2, heat shock 27 kDa protein, calreticulin and calmodulin, whose expression was elevated in hepatoma cells, glutathione-S-transferase P was identified from hepatoma cells in which its level was 18-fold higher compared to human liver cells. Two spots were identified as the homologs of reticulocalbin for the first time in hepatoma cells and their expression increased compared to liver cells. However, tubulin beta-1 chain and natural killer cell enhancing factor B were downregulated in hepatoma cells. A tumor suppressing serpin, maspin precursor, was identified from one spot whose quantity was much higher in the normal liver cell line. More interestingly, epidermal fatty acid-binding protein (E-FABP) and fatty acid-binding protein, adipocyte-type (A-FABP), were detected in liver cells but not in hepatoma cells. The functional implication of the identified proteins was discussed.

[The St14 (DXS 52) VNTR in a Guangdong Han population and detection of hemophilia A carriers]

OBJECTIVE

To investigate the genetic polymorphism of the St14 (DXS 52) variable number tandem repeat (VNTR) in normal individuals in Guangdong, and to evaluate the efficacy of this marker for the gene diagnosis of hemophilia A.

METHODS

125 unrelated healthy individuals (male 21, female 104) and 4 hemophilia A families were detected using amplified-fragment-length polymorphism (Amp-FLP).

RESULTS

11 allelic fragments ranging from 700 to 1,810 bp in size and 7 different genotypes in males, 17 different genotypes in females were observed, respectively. The allele frequencies were 0.0044 to 0.4803. The polymorphism information contents (PIC) was 0.7335, and the heterozygosity was 0.432. Four families with hemophilia A were analyzed and 2 of them were informative for linkage analysis. In one family, 2 females were determined to be normal individuals, not carriers, one female carrier was detected in the other family.

CONCLUSION

St14 (DXS 52) was a useful polymorphism marker for carrier detection of hemophilia A in southern Chinese population, and it was different from those in Caucasian.

Expression of isolated C-type carbohydrate recognition domains

A galactose-binding lectin from the venom of the snake Trimeresurus stejnegeri consists of isolated carbohydrate recognition domains, belonging to group VII of the C-type animal lectins. As a first step toward determining the tertiary structure of the galactose-specific lectin, we produced the lectin in Escherichia coli. By in vitro refolding and affinity chromatography, modest amounts (8 mg/liter) of active recombinant proteins were obtained. The recombinant protein was homogeneous, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and mass spectrometry. Its amino acid sequence without the initiated methionine at the N-terminus was also characterized by mass spectrometry. The data of hemagglutination and enzyme-linked lectin binding assays demonstrated that the recombinant lectin showed similar sugar-binding activity as the native protein. In addition, fluorescence spectroscopy and circular dichroism also showed obviously their structural similarity.

[Correction of dento-maxillofacial deformities by using both of orthodontics and orthognathic surgery]

OBJECTIVE

To study the clinical results and stability after correction of dento-maxillofacial deformities by using both of orthodontics and orthognathic surgery.

METHODS

A group of 45 patients with dento-maxillofacial deformities were corrected by preoperative orthodontics-orthognathic surgery-postoperative orthodontics procedure. As a control, another group of 64 patients with the deformities were corrected by orthognathic surgery only. The facial appearance, occlusion and stability of two groups after correction were investigated and compared.

RESULTS

In orthodontics and orthognathic surgery group, 62.2% of patients declared that their mastication were improved. Relapse rate of deformities was 4.4%. In orthognathic surgery group, 42.2% of patients declared that their mastication were improved. Relapse rate of deformities was 9.4%.

CONCLUSIONS

Using both of orthodontics and orthognathic surgery to correct dento-maxillofacial deformities is a good approach to improve results of correction, keep balance of occlusion and reduce the relapse of the deformities.

[Artery denuded model and effects of three kinds of antisense c-myc RNA]

OBJECTIVE

To investigate the effects of antisense c-myc on injured vascular wall.

METHODS

Three recombinant retroviral expression vectors, aM1, aM2 and aM3, which loading the reverse fragment of exon1, 2 and 3 respectively, were transferred into denuded rabbit femoral artery wall and were assayed 21 days after operation.

RESULTS

(1) The regions of rabbit femoral artery were not only convenient for injury control, drug giving and material drawing, but also gave a neointimal area to media area vatio of 1.37:1. Their intensity and area of c-myc expression in media increased to 1.8 and 1.5 fold of normal value. (2) c-myc expression in aM2, aM3 and aM1 was reduced by 37.5%, 20.8%, and 17.8% with media intensity, 71.5%, 57.2%, and 61.6% with media area and 31.3%, 20.8%, and 17.8% with neointimal intensity respectively. (3) Neointimal area/media area of aM2 group reduced by 72.6%, aM3 group reduced by 35.2%, aM1 group had no significant difference comparing with control group. (4) Proliferating cellular nuclear antigen (PCNA) in the intimal and media of the three antisense transferred groups was enhanced with their expressive intensities, but reduced with expressive areas significantly. (5) With the declining of neointimal area/media area, alpha-SM actin expression in the intimal and media of the three antisense transferred groups was significantly increased (aM2 > aM3 > aM1).

CONCLUSION

(1) Rabbit femoral artery denuded model is a satisfactory animal model. (2) Antisense c-myc transferring can reduce or resist the c-myc increase in injured artery wall, resist neointimal hyperplasia and smooth muscle cells dedifferentiation,especially c-myc exon 2 antisense RNA vector aM2.

[Detection of R277Q mutation of SRD5alpha2 gene by amplification refractory mutation system]

OBJECTIVE

To set up a simple method for identifying the mutation of R227Q of SRD5alpha2 gene which is one of the most common mutations in congenital hypospadias in China.

METHODS

The amplification refractory mutation system(ARMS) was employed in detecting the SRD5alpha2 gene R227Q mutation in congenital hypospadias confirmed by PCR-SSCP and DNA sequencing.

RESULTS

The ARMS was successfully applied to the detection of the R227Q mutation of SRD5alpha2 gene. Three out of 23 congenital hypospadias were positive for R227Q mutation. The mutations determined by ARMS were in full agreement with those obtained by the DNA sequencing.

CONCLUSION

This is a simple, rapid and accurate method. It can be used for detecting the SRD5alpha2 gene R227Q mutation in congenital hypospadias and male pseudohermaphroditism.

Characterization and analysis of a novel glycoprotein from snake venom using liquid chromatography-electrospray mass spectrometry and Edman degradation

An N-linked glycosylation in a novel C-lectin protein from snake venom was observed by Edman degradation and liquid chromatography-electrospray mass spectrometry. The peptides obtained by trypsin cleavage were analyzed to confirm the amino acid sequence and Asn5 was found to be the N-glycosylation site. The result was further confirmed by N-glycosidase digestion. In addition, the protein and tryptic peptides with and without glycan chain were characterized by mass spectrometry according to the mass difference. The glycopeptide obtained from proteolytic digestion was analyzed and the glycoforms were identified as high-mannose type by tandem MS coupled with alpha-mannosidase digestion. An oxidized Met residue was detected and located in the protein by mass spectrometry.

Analysis of 8-aminonaphthalene-1,3,6-trisulfonate-derivatized oligosaccharides by capillary electrophoresis-electrospray ionization quadrupole ion trap mass spectrometry

Dextran was partially hydrolyzed with 0.1 mol/l HCl and the hydrolysate was derivatized with 8-aminonaphthalene-1,3,6-trisulfonate (ANTS) by reductive amination. The derivatized-oligosaccharide mixture was separated by capillary electrophoresis (CE) in a buffer of 1% HAc-NH4OH, pH 3.4, and the separated components were detected on-line by electrospray ionization quadrupole ion trap mass spectrometry (ESI-QIT-MS) in the negative ion mode. A mass accuracy lower than 0.01% could be achieved and as low as 1.6 pmol of detxran octaose could be detected. ANTS-derivatized dextran oligosaccharide with a degree of polymerization (DP) lower than 6 produced both [M-H]- and [M-2H]2- ions, whereas those with a DP of 6 or higher than 6 produced only [M-2H]2- ion. As 1< or =DP< or =6, the percentage of [M-2H]2- ion in the total ions of [M-H]- and [M-2H]2- was found to be a linear function of the logarithmic DP. Molecular mass determination with ESI-QIT-MS strengthens the power of CE analysis of oligosaccharides.

Analysis of recombinant and modified proteins by capillary zone electrophoresis coupled with electrospray ionization tandem mass spectrometry

A method for rapid characterization of recombinant and modified proteins with known sequences is described. The analytical system consists of a capillary zone electrophoresis (CZE) instrument coupled to an electrospray ionization ion trap tandem mass spectrometer via a sheath-flow interface. Following the procedure consists of proteolytic fragmentation, CZE peptide separation, tandem mass spectrometry (MS-MS) analysis of separated peptides, sequence database search and monitoring of the specific peptides, C 125 S mutated interleukin 2 (S-125-IL2) and bovine beta-casein were characterized as a model of recombinant protein and naturally modified protein, respectively. A tryptic peptide mixture derived from the synthetic salmon calcitonin (s-CT) was also analyzed to test the performance of the system. Although a conventional sheath-flow interface with much higher flow-rate compared to the microspray interface and nanospray interface was used, the proteins were identified at the low picomole level.

[Analysis of prenatal diagnosis for 120 cases of beta-thalassemia]

OBJECTIVE

To analyse the results of prenatal gene diagnosis of beta-thalassemia.

METHODS

By using the reverse dot blot method with an allele specific oligonucleotide probe(ASO/DRB).

RESULTS

In 120 cases of prenatal gene diagnosis, there are 30 of normal fetal; 63 of beta-thalassemia heterozygotes; 26 of beta-thalassemia homozygotes or dual heterozygotes; one of no diagnosis because the beta mutated gene can not be detected in one side of the parent.

CONCLUSIONS

Acording to the follow-up studies, the babies unconcordance with prenatal diagnosis have not been found, the accuracy rate being 100%. Amniotic fluid specimen of the middle stage of pregnancy is the best for detection.

[Detection of alpha-thalassemia 1 gene among 142 beta-thalassemia gene carriers]

OBJECTIVE

To investigate the coincidental rate of double heterozygous state of beta-thalassemia and alpha-thalassemia 1 in Guangdong area.

METHODS

One handred and forty-two DNA samples with beta-thalassemia trait were amplified by polymerase chain reaction(PCR) to detect alpha-thalassemia 1 gene. The positive cases were further detected by mutant primer PCR or by reverse dot blot hybridization (ASO/RDB) to confirm their beta-thalassmia mutations.

RESULTS

Thirteen cases (9.15%) were identified to combine with alpha-thalassemia 1 gene. The mutant loci of beta-globin gene in these cases were that 5 were in CD 41-42 (-TCTT), 3 in IVS-2-654(C-->T), 2 in CD 17 (A-->T) and 3 in CD 71-72 (+A), CD 43(G-->T) and -28 (A-->G), respectively.

CONCLUSIONS

The occurrence of this dual heterozygotes among beta-thalassemia trait is relatively frequent and it should be paid much attention to in genetic counselling and prenatal diagnosis of thalassemia in this area.

[Genetic diagnosis of alpha and beta thalassemia dual heterozygote]

OBJECTIVE

To perform genetic diagnosis of alpha and beta thalassemia dual heterozygotes.

METHODS

PCR and beta-thalassemia allele specific oligonucleotide probe/reverse dot blot(ASO/RDB) techniques were used.

RESULTS

Six cases of suspected alpha-thalassemia-1 and beta-thalassemia dual heterozygotes were found in genetic counseling and prenatal diagnosis. On genetic diagnosis, they were all Southeast Asia(SEA) type of alpha-thalassemia-1 and beta-thalassemia (--SEA/alpha alpha, beta T/beta A) dual heterozygotes. Out of them, 3 cases were alpha-thalassemia-1 and beta 41-42 (-TCTT), 2 were alpha-thalassemia-1 and beta-28(A-->T) and 1 was alpha-thalassemia-1 and beta IVS-II-654(C-->T) double heterozygotes.

CONCLUSION

The detection of thalassemia dual heterozygotes facilitates the prenatal diagnosis with more precision.

[Application of antigen linked with chemicals on nitrate cellulose membrane for dot-enzyme immunoassay]

HCMV-IgG in sera of pregnant women was detected by means of dot-enzyme immunoassay (DEIA), in which antigen was cross-linked on nitrate cellulose membrane through chemical reagent. The results showed better repetition by DEIA, compared with ELISA, and no significant differences were noted between the two methods in the rates of detecting HCMV-IgG in positive, weak positive and negative sera. The rate of agreement was 93.2%. In examining the sera which had been examined by ELISA for three times with the same, results the sensitivity, specificity, index and efficiency of diagnosis by DEIA were 100%, 96.6%, 196.6% and 98.7% respectively. Since this method is convenient, fast, of good repetition, economical and its diagnosis index meets the application criterion, it is more suitable for clinical laboratories.

[Application of PCR-SSCP to rapid genetic diagnosis of adult polycystic kidney disease]

OBJECTIVE

To explore a rapid and easy-to-do linkage analysis in families with adult polycystic kidney disease(APKD).

METHODS

The polymorphism of SM7, a SRS which lies proximal to PKD1, among Chinese people was analysed using PCR, PAGE and silver staining. SM7-SSLP linkage analyses were performed in two APKD families and the results were compared with these of 3'HVR/Pvu II linkage analyses in the same families.

RESULTS

Seven kinds of SM7 alleles were observed in the 67 unrelated Chinese people. The heterozygosity was 52.5% and PIC 0.62. The most common allele was Y9. The result was close to that of Harris's report, showing that there is no marked difference in the polymorphism of SM7 between Chinese and Caucasian. The results of SM7-SSLP linkage analyses in the two APKD families consisted with the results of 3'HVR/Pvu II linkage analyses though in one family the information provided by SM7 was less than 3'HVR.

CONCLUSION

The polymorphism of SM7 locus is high in Chinese and SM7 can be used in linkage analysis as a valuable marker. SSLP linkage analysis proved to be avery useful way for rapid genetic diagnosis of APKD providing that a highly polymorphic marker is used, and the result can be analysed easily.

Exon-by-exon screening for RB germline mutations using Heteroduplex-SSCP analysis

OBJECTIVE

To disclose the nature of RB1 germline mutations in Chinese and to develop a practical and effective way for mutational screening.

METHODS

Leukocyte DNA was prepared from 8 Chinese patients with hereditary retinoblastoma. PCR combined with nonisotopic heteroduplex-SSCP analysis was used to screen leukocyte DNA for RB1 germline mutations, exon-by-exon, without the use of restriction endonuclease digestion. The mutations were finally identified by sequencing. In order to testify the effectiveness of this method, the same method was used to detect other 17 samples which have been previously analyzed by other methods.

RESULTS

Heterozygous germline mutations were detected in the leukocyte DNA of 6 out of 8 Chinese patients: G del/codon 46, T del/codon 131, CAGAA del/codon 257-258, GCAgta-->GCAgca/donor of exon 16, C-->T/codon 661, and C-->T/codon 787. Heteroduplex-SSCP analysis may detect RB1 germline mutations in 68% (17/25) unselected patients, which is more effective than SSCP(56%) or heteroduplex analysis(64%) alone. The corrected RB1 mutation detection rate may be 80% if the samples were previously analyzed by Southern blotting, which is much higher than those reported on literature.

CONCLUSION

Mutations involving a few base pairs in RB1 gene are common in Chinese. Heteroduplex-SSCP analysis is more useful and effective than SSCP or heteroduplex analysis alone for the rapid screening for unknown mutations.

[Experimental study on bone formation in a denser coral used for repairing cortical defects in dogs]

The present study was designed to investigate a coral skeleton, Favites, which was originated from the reef builders in Hainan island, as a bone substitute. The coral Favites, like porites, is composed of anagonite (CaCO3), but contains less volume of porosity, higher strength and denser construction than Porites. After implanted into cortical bone defects in mandibles and femurs of dogs, skeleton fragment of coral Favites demonstrated good biocompatibility and biodegradability. A resorption of the implant and a simultaneous apposition of new bone was observed. Coral Favites was totally replaced by newly formed bone after a period of time from 6-8 months. Compared to Porites, Favites has a lower rate of resorption and therefore the defects of host bone are repaired completely without any lost of bone volume. The results showed that coral Favites may be used as a bone substitute for the segmental defects of mandibles.

Preliminary report of molecular detection of retinoblastoma gene mutations

To develop gene diagnosis for retinoblastoma predisposition, it is necessary to disclose the retinoblastoma gene mutations or deletions in detail. Genomic DNA from tumor and peripheral white blood cells in 33 patients with retinoblastoma was detected with 3.8kb probe derived from 3' end of retinoblastoma gene cDNA. The gene abnormalities, including deletion, partial deletion and rearrangement, were found in 18 patients. Further research will be aimed at microdeletions or mutations for those patients without detectable variations in Southern hybridization.