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Biomedical subjects

L Kang

Publications and source records attributed to L Kang.

At least 19 recordsLinked to original sources
PubMed2026

Genome-wide association study of body weight and body size traits in Langya hens.

Langya chicken is a Chinese indigenous chicken breed with high genetic diversity. To systematically analyse the genetic basis of body size traits, eight traits (including BW, comb shape, and body size) of 2 952 Langya hens were measured at 130 days of age and at first egg of age. A total of 9 708 856 high-quality single-nucleotide polymorphisms (SNPs) were obtained through whole-genome resequencing and used for subsequent genetic parameter estimation and genome-wide association study (GWAS). The results of genetic parameter analysis revealed significant differences in the SNP heritability of different body size traits, with an overall range of 0.13-0.64. In particular, BW, comb length, comb height, and tibia length exhibited moderate-to-high heritability (0.34-0.64) during both developmental stages. GWAS revealed significantly associated SNP loci distributed across multiple chromosomal regions, indicating that body size traits have a complex multilocus genetic regulatory structure and that some chromosomal regions recur for different body size traits and during different developmental stages, showing potential pleiotropic effects or shared genomic regions. Notably, multiple stable body size trait-associated regions were identified on Gallus gallus autosome (GGA) 1, 4, and 27, including genomic regions on GGA1 (167.56-178.18 Mb), GGA4 (68.24-81.17 Mb), and GGA27 (5.22-6.73 Mb), in which significantly associated signals were repeatedly detected for multiple body size traits, such as BW and tibia length. The significant SNPs in the above regions were characterised by strong linkage disequilibrium and were associated with multiple body size traits, indicating that these SNPs may serve as important genetic hotspots for the regulation of chicken body shape and structure. Candidate genes annotated in these core regions include NCAPG, KPNA3, LDB2, PPARGC1A, FNDC3A, SOST, RB1, STON2, and TARP; the functions of these genes are involved mainly in the regulation of cell proliferation, energy metabolism, bone development, and tissue growth. NCAPG was consistently associated with multiple traits at both developmental stages. Functional enrichment analysis further revealed that these candidate genes were significantly enriched in the phosphatidylinositol, GnRH, energy metabolism, skeletal development and protein biosynthesis signalling pathways. The genetic characteristics of Langya chicken body size traits during the growth stage at the genome-wide level and the underlying molecular mechanisms were systematically revealed in this study. The findings provide important candidate gene resources and a theoretical basis for the screening of molecular markers for body size traits and the genomic breeding of regional chicken breeds.

Candidate genes↗
PubMed2006

A simple fully integrated contact-coupled wear prediction for ultra-high molecular weight polyethylene hip implants.

A fully coupled contact and wear model was developed in the present study for hip implants employing an ultra-high molecular weight polyethylene (UHMWPE) cup in combination with a metallic or ceramic femoral head. A simple elasticity equation based on the concept of constrained column model was employed to solve the contact mechanics between the acetabular cup and the femoral head under the three-dimensional physiological loading condition. The wear model was based on the classical Archard-Lancaster equation in common with all other studies reported in the literature. The fully coupled contact and wear model was applied to both conventional and cross-linked UHMWPE cups under a wide range of design parameters such as the clearance and the femoral head radius. The predicted linear and volumetric wear as well as their rates for conventional UHMWPE cups were found to be in good agreement with those obtained from a similar analysis by Maxian but using the finite element method for the contact mechanics analysis. The predicted maximum contact pressure was found to decrease rapidly within the first 10(6) cycles, and below the limit to cause plastic deformation within the UHMWPE cup with a nominal radial clearance of 0.2 mm. The effect of the clearance between the head and the cup on the predicted wear was found to be negligible. For the cross-linked UHMWPE cup with relatively large diameters up to 48 mm and a fixed outside diameter of 50 mm, the predicted wear, which was found to increase with increasing femoral head radius, remained small owing to the small wear factor associated with these materials. Furthermore, if the head diameter increases beyond 42 mm, a rapid increase in the contact pressure was predicted, owing to the decrease in the wall thickness of the cross-linked UHMWPE cup.

Animals↗
PubMed2005

APOE epsilon2/epsilon4 polymorphism and cerebral microbleeds on gradient-echo MRI.

The association of APOE genotypes with cerebral microbleeds (CMBs) was examined on the basis of the location of CMBs in 414 patients who were admitted primarily because of stroke. With respect to possession of the epsilon2 or epsilon4 allele, the adjusted odds ratio was 1.94 (1.05 to 3.58) for lobar CMBs but 1.21 (0.69 to 2.11) for nonlobar CMBs. This suggests that the pathogenesis of CMBs may differ depending on their location.

Age Factors↗
PubMed2005

SMGA gels for the skin permeation of haloperidol.

Small molecule gelling agent (SMGA) gels were developed using the gelator GP-1 in the solvents, namely, isostearyl alcohol (ISA) and propylene glycol (PG), to deliver haloperidol through the skin. The concentrations of the drug, haloperidol, the enhancer, farnesol and the gelator, GP-1 are 3 mg/ml, 5% (w/v) and 5% (w/v), respectively. The study employed a three-factor full factorial statistical design to investigate the influence of factor level changes on the permeability coefficient and permeation lag-time of haloperidol. Gels were prepared by raising temperature to 120 degrees C, followed by natural cooling under room temperature of 22+/-1 degrees C. The rheological properties of the gels were examined with a strain-controlled dynamic mechanical method. The in vitro permeation study was conducted with automated flow-through type cells. The gels successfully incorporated the drug and enhancer without losing their aesthetic properties. The in vitro human skin permeation study showed the permeation of the drug in ISA-based gels reached the pseudo steady state faster than PG-based gels and were less affected by gelator. PG-based gels delivered the drug at a faster rate with the incorporation of the enhancer. GP-1 did not influence the drug permeation rate but it increased permeation lag-time. The co-existence of gelator or enhancer increased the lag-time to a larger extent than when used separately. The novel SMGA gels are suitable for topical or transdermal delivery.

Administration, Cutaneous↗
PubMed2005

Stress fractures of the femoral shaft in women's college lacrosse: a report of seven cases and a review of the literature.

BACKGROUND: Stress fractures do not often occur in the shaft of the femur. They are more common in the femoral neck, the tibial shaft, the metatarsals, and other bones of the foot. In female athletes, stress fractures classically afflict the distance runner, the ballerina, the gymnast, and the figure skater. OBJECTIVES: To describe the clinical presentation, diagnosis, treatment, and outcome of seven college female lacrosse players with femoral shaft stress fractures, and review the literature. RESULTS: The unusual results of this study support the principle that clinical suspicion should be high when treating any female athlete regardless of the sport. In this case series, an abrupt change in the quality of the running surface during the competitive training season was the only underlying common thread among the athletes. CONCLUSION: The findings suggest that risk factors for the female athlete are variable and are no longer limited to the undernourished or overtrained.

Adult↗
PubMed2004

In vivo motion of the scaphotrapezio-trapezoidal (STT) joint.

It has previously been shown that the articulation of the scaphotrapezio-trapezoidal (STT) joint can be modeled such that the trapezoid and trapezium are tightly linked and move together on a single path relative to the scaphoid during all directions of wrist motion. The simplicity of such a model is fascinating, but it leaves unanswered why two distinct carpal bones would have a mutually articulating surface if there were no motion between them, and how such a simplistic model of STT joint motion translates into the more complex global carpal motion. We performed an in vivo analysis of the trapezoids and trapeziums of 10 subjects (20 wrists) using a markerless bone registration technique. In particular, we analyzed the centroid spacing, centroid displacements, kinematics, and postures of the trapezoid and trapezium relative to the scaphoid. We found that, on a gross level, the in vivo STT motion was consistent with that reported in vitro. In addition, we found that the magnitude of trapezoid and trapezium motion was dependent upon the direction of wrist motion. However, we also found that when small rotations and displacements are considered there were small but statistically significant relative motions between the trapezoid and trapezium (0.4 mm in maximum flexion, 0.3 mm in radial deviation and at least 10 degrees in flexion extension and ulnar deviation) as well as slight off-path rotations. The results of this study indicate that the STT joint should be considered a mobile joint with motions more complex than previously appreciated.

Adult↗
PubMed2003

Superinfection of Laodelphax striatellus with Wolbachia from Drosophila simulans.

Wolbachia are maternally inherited, intracellular alpha-proteobacteria that infect a wide range of arthropods. They manipulate the reproduction of hosts to facilitate their spread into host populations, through ways such as cytoplasmic incompatibility (CI), parthenogenesis, feminization and male killing. The influence of Wolbachia infection on host populations has attracted considerable interest in their possible role in speciation and as a potential agent of biological control. In this study, we used both microinjection and nested PCR to show that the Wolbachia naturally infecting Drosophila simulans can be transferred into a naturally Wolbachia-infected strain of the small brown planthopper Laodelphax striatellus, with up to 30% superinfection frequency in the F(12) generation. The superinfected males of L. striatellus showed unidirectional CI when mated with the original single-infected females, while superinfected females of L. striatellus were compatible with superinfected or single-infected males. These results are, to our knowledge, the first to establish a superinfected horizontal transfer route for Wolbachia between phylogenetically distant insects. The segregation of Wolbachia from superinfected L. striatellus was observed during the spreading process, which suggests that Wolbachia could adapt to a phylogenetically distant host with increased infection frequency in the new host population; however, it would take a long time to establish a high-frequency superinfection line. This study implies a novel way to generate insect lines capable of driving desired genes into Wolbachia-infected populations to start population replacement.

Animals↗
PubMed2001

Preparation and characterization of two-phase melt systems of lidocaine.

The melting point of lidocaine was significantly lowered when mixed with thymol and/or aqueous ethanol. Mixtures of lidocaine and thymol at ratios within the range of 30:70-70:30 (w:w) became homogeneous oils at 25 degrees C. In a pH 9.2 carbonate buffer containing 25% ethanol, lidocaine (5%, w:w) also liquefied at 25 degrees C. The studies led to the development of novel two-phase melt systems of lidocaine (TMS) which consisted of a highly concentrated oil phase of lidocaine and an alcoholic aqueous phase. A compositional phase diagram showed that in aqueous dispersions of lidocaine, concurrent use of thymol and ethanol depressed the melting point of lidocaine more effectively than when they were used individually. Both thymol and aqueous ethanol were necessary as melting point depressing agents to achieve the highest possible lidocaine concentration of 87% (w:w) in the oil phase of a TMS at 25 degrees C. Containing an internal oil phase and an external aqueous phase at ambient temperature, such a TMS can be readily formulated into topical O/W cream after addition of proper surfactants and thickening agents. In an anesthetic activity test using mouse tail-flick model, a 5% lidocaine cream prepared was highly effective as shown by the prolonged latency time of the mice to a heat stimulus as compared with a placebo (P<0.05).

Analgesia↗
PubMed2001

Modeling and prediction for discharge lifetime of battery systems using hybrid evolutionary algorithms.

A hybrid evolutionary modeling algorithm (HEMA) is proposed to build the discharge lifetime models with multiple impact factors for battery systems as well as make predictions. The main idea of the HEMA is to embed a genetic algorithm (GA) into genetic programming (GP), where GP is employed to optimize the structure of a model, while a GA is employed to optimize its parameters. The experimental results on lithium-ion batteries show that the HEMA works effectively, automatically and quickly in modeling the discharge lifetime of battery systems. The algorithm has some advantages compared with most existing modeling methods and can be applied widely to solving the automatic modeling problems in many fields.

Algorithms↗
PubMed2001

[Study on activity of inner inhibitory substances of Acanthopanax senticosus (Rupr. et Maxim) harms fruits and seeds].

OBJECTIVE: By studying on the inner inhibitory substances of Acanthopanax senticosus fruits and seeds, the reason for dormancy of the Seeds was investigated. METHOD: First, the raw extracts of Acanthopanax senticosus fruits and seeds were prepared and determined by biological methods. Then, the ether extract of Acanthopanax senticosus fruits was prepared and the components were separated by paper chromatography and each section with different Rf value was determined, respectively. RESULT AND CONCLUSION: Inner inhibitory substances with high activity exists in Acanthopanax senticosus fruits and their outer coats, middle coats and the seeds. The inner inhibitory substances showed stronger inhibitory effect on the germination of Brassica chinensis seeds than the growth of its younger roots. The Rf 0.1 section of the ether extract of Acanthopanax senticosus fruit coats showed the strongest inhibitory activity on the germination of Brassica chinensis seeds and the growth of its young roots. The rough extracts of Acanthopanax senticosus fruits could inhibit the activity of the (alpha-amylase in the process of wheat seeds germination. The dormanvy of Acanthopanax senticosus seeds is related to the inhibitory substances with high activity in Acanthopanax senticosus fruits and seeds.

Brassica↗
PubMed2000

Physicochemical studies of lidocaine-menthol binary systems for enhanced membrane transport.

The melting properties of lidocaine and l-menthol binary systems were studied using differential scanning calorimetry (DSC). A eutectic mixture was obtained for the lidocaine:menthol ratio of 30:70 (w:w) with a eutectic point of 26 degrees C. The binary melt systems formed within a range of 30:70-50:50 (w:w) remained as homogeneous oils at ambient temperature. The solubilities of pure lidocaine and lidocaine from the binary melt systems were determined with and without propylene glycol in pH 8.0 phosphate buffer. Lidocaine from the melt systems was less soluble in the buffers due to the partition of lidocaine between the oil and aqueous phases. The addition of propylene glycol to the buffer significantly increased both the solubility and heat of solubilization of lidocaine. The permeation rates of lidocaine from the binary melt systems across shed snake-skin were concentration dependent and significantly higher than those from the reference solutions.

Anesthetics, Local↗
PubMed2000

The transcription factor E2F1 modulates apoptosis of neurons.

The transcription factor E2F1 is known to mediate apoptosis in isolated quiescent and postmitotic cardiac myocytes, and its absence decreases the size of brain infarction following cerebral ischemia. To demonstrate directly that E2F1 modulates neuronal apoptosis, we used cultured cortical neurons to show a temporal association of the transcription and expression of E2F1 in neurons with increased neuronal apoptosis. Cortical neurons lacking E2F1 expression (derived from E2F1 -/- mice) were resistant to staurosporine-induced apoptosis as evidenced by the significantly lower caspase 3-like activity and a lesser number of cells with apoptotic morphology in comparison with cortical cultures derived from wild-type mice. Furthermore, overexpressing E2F1 alone using replication-deficient recombinant adenovirus was sufficient to cause neuronal cell death by apoptosis, as evidenced by the appearance of hallmarks of apoptosis, such as the threefold increase in caspase 3-like activity and increased laddered DNA fragmentation, in situ endlabeled DNA fragmentation, and numbers of neuronal cells with punctate nuclei. Taken together, we conclude that E2F1 plays a key role in modulating neuronal apoptosis.

Adenoviridae↗
PubMed2000

[cDNA cloning and sequence analysis of the seventh segment of maize rough dwarf virus genome].

The double strand RNA of maize rough dwarf virus (MRDV) was prepared from the maize samples showing symptoms which was from the Luanchen county of Heibei province of China. The primers were designed according to the known sequence of MRDV, the cDNA sequence of the seventh segment of MRDV was obtained by RT-PCR, the S7 sequence was analyzed by computer after sequencing. The results showed: the full length of the S7 cDNA is 1936 bp and equal to that of the S7 cDNA from abroad, the two open reading frame(ORF1 and ORF2) contained in the S7 segment are also unchanged. In comparison with the S7 segment from Italy, the homology of S7 nucleotide is 87.7% and the homology of ORF1 amino acid sequence is 91.6%. However, the MRDV S7 segment and the rice black strike dwarf virus S8 segment showed 95.5% nucleotide identities and 93.5% ORF1 amino acid identities.

Amino Acid Sequence↗
PubMed2000

[A novel apoptotic related gene--homocysteine-induced gene HCY-2].

OBJECTIVE: To investigate the mechanisms resulting in cardiovascular diseases and birth defect. METHODS: Induced screening and differential display, Northern blot, and immunohistochemistry assay were applied to clone the homocysteine-induced gene HCY-2 and detect the expression of HCY-2 gene respectively. RESULTS: A novel HCY-induced full length cDNA--HCY-2 which encodes 142 amino acids was obtained from vascular smooth muscle cells of rats. Results of the Northern blot and immunohistochemistry assays suggest that it widely expresses in many kinds of tissues such as heart, kidney, brain, liver, and lung. In vitro, we transferred recombinant HCY-2 gene into endothelial cells and found that it could induce apoptosis and DNA injury. In vivo, HCY-2 gene could induce chicken embryo cells apoptosis and embryo malformation. CONCLUSIONS: The results indicated that HCY-2 gene might be a novel apoptosis-inducing gene and might be involved in the pathogenesis of cardiovascular diseases and birth defects induced by hyperhomocysteinemia.

Amino Acid Sequence↗
PubMed1999

Causes and consequences of microsatellite instability in endometrial carcinoma.

Genetic instability of microsatellite repeat sequences [microsatellite instability (MI)] is commonly seen in tumors associated with the hereditary nonpolyposis colorectal cancer syndrome and is a result of inactivating mutations in any of several genes involved in a particular pathway of DNA mismatch repair. Sporadic (i.e., nonhereditary) manifestations of several tumor types, including colorectal, gastric, and endometrial carcinomas, also exhibit MI in a significant fraction of cases. Many MI+ sporadic colorectal carcinomas are associated with somatic mutations of mismatch repair genes, and several genes with coding region microsatellites are frequently mutated as a result in these cancers. The molecular causes and consequences of MI in sporadic endometrial carcinomas remain obscure, however. The aims of this study were: (a) to identify a series of sporadic endometrial carcinomas with clear evidence of MI; (b) to determine the extent to which somatic alterations in mismatch repair genes are associated with this MI; and (c) to establish whether the genes containing coding region microsatellite repeats that are known to be disrupted in MI+ gastrointestinal cancers are also disrupted in MI+ endometrial carcinomas. Matched pairs of normal and tumor DNA from 57 consecutive cases of endometrial carcinoma were examined for evidence of MI using a consensus panel of microsatellite markers. Fourteen cases (25%) displayed unequivocal evidence of MI, consistent with previously published estimates of the incidence of MI+ sporadic endometrial carcinoma. These cases were subjected to a mutation screen of the coding regions and exon-intron boundaries of the mismatch repair genes MSH2 and MLH1. Although several polymorphisms were detected, no clearly deleterious mutations were found in either of these genes. Notably, however, hypermethylation of the MLH1 promoter region was identified in 10 of 14 (71%) MI+ cases. Somatic mutations in coding region microsatellite repeats in the TGFbetaIIR, IGFIIR, BAX, E2F4, MSH3, MSH6, BRCA1, and BRCA2 genes were generally rare. Four MI+ tumors (29%) contained somatic mutations in the PTEN gene, only one of which was likely the result of MI. These data indicate that somatic mutational inactivation of known mismatch repair genes does not account for the great majority of sporadic endometrial carcinomas with MI and that a significant fraction of these cases may instead be causally associated with hypermethylation of the MLH1 promoter. Furthermore, genes with coding region microsatellites that are frequently mutated in MI+ gastrointestinal cancers are rarely mutated in MI+ endometrial cancers, implying the existence of alternative molecular targets for the tumorigenic effects of MI in this tumor type.

Adaptor Proteins, Signal Transducing↗
PubMed1999

HPLC assay of Lidocaine in plasma with solid phase extraction and UV detection.

A sensitive and reliable method based on solid-phase extraction and reversed-phase liquid chromatography was developed and validated for the quantitation of Lidocaine (Lid) in dog plasma. Phenacemide was used as an internal standard (IS) in the extraction which employed C18 solid-phase extraction cartridges. The washing and eluting solutions were 2 ml acetonitrile-pH 9.0 phosphate buffer (10:90 v/v) and 0.5 ml acetonitrile-pH 4.0 phosphate buffer (40:60 v/v). respectively. The eluent obtained from the cartridge was directly analyzed on a reversed-phase ODS column with UV detection at 210 nm. A clean chromatogram and high sensitivity were achieved at this wavelength. The mobile phase was acetonitrile and pH 5.9 phosphate buffer (20:80 v/v). The retention times were 6.4 and 7.2 min for Lid and IS, respectively, at a flow rate of 1.0 ml min(-1). The mean absolute recovery was 96.6% (n = 9) with a CV of 3.8% for Lid and 81.7% with CV of 2.5% (n = 3) for IS. The limit of quantitation was 20 ng ml(-1), with the intra- and inter-day precisions (n = 5) of 4.4 and 3.4%, respectively, and the intra- and inter-day accuracies (n = 5) of -4.3 and -5.0%, respectively. For the analyses of Lid in spiked plasma samples at 20, 100 and 200 ng ml(-1), the overall mean intra- and inter-day precisions (n = 15) were 3.9 and 4.9%, respectively, and the overall mean intra- and inter-day accuracies (n = 15) were -3.7 and -4.6%, respectively. The correlation coefficients for calibration plots in the range 20-1000 ng ml(-1) in plasma were typically higher than 0.998. The suitability of the method was demonstrated by the study in a beagle dog receiving a low intravenous dose of Lid.

Acetonitriles↗
PubMed1999

Effects of LPS on transport of indocyanine green and alanine uptake in perfused rat liver.

Lipopolysaccharide (LPS) initiates cholestasis. Whether this process is mediated by tumor necrosis factor-alpha (TNF-alpha) and whether the cholestatic response to LPS is associated with intrahepatic accumulation of possibly toxic substances are under debate. To study these questions the hepatic uptake and biliary excretion of indocyanine green (ICG) was examined in the isolated perfused rat liver 18 h after intravenous treatment of rats with either saline, 1 mg/kg body wt LPS, or LPS and intraperitoneal pentoxifylline (POF) (n = 6 in each group). POF inhibits TNF-alpha release after LPS administration. LPS induced a typical acute-phase response with increased mRNA for acute-phase proteins, reduced albumin mRNA, and increased hepatic uptake of alanine. Intrinsic hepatic clearance of ICG in controls (1.01 +/- 0.05 ml. min(-1). g liver(-1)) was similarly decreased by LPS alone (0.62 +/- 0.04 ml. min(-1). g(-1); P = 0.002 vs. control) or combined with POF (0.66 +/- 0.06 ml. min(-1). g(-1)). A kinetic analysis indicated that LPS reduced both uptake and excretion processes in a balanced manner, so that intrahepatic ICG content was unaffected or even slightly reduced, as confirmed by measurement of ICG contents in the perfused livers. In livers from parallel-treated nonperfused rats, mRNA for the organic anion transporting protein-1 (Oatp1, which is likely to mediate ICG uptake) was unaffected by LPS, whereas the concentration of Oatp1 protein was reduced. Thus LPS induced an acute-phase response that included downregulation of ICG uptake by reduction of Oatp1 protein concentration, possibly at a posttranscriptional level. TNF-alpha appears not to be the mediator because POF did not modify these LPS effects.

Alanine↗