Biomedical subjects

Haixia Liu

Publications and source records attributed to Haixia Liu.

6 recordsLinked to original sources

PubMed2026

Functions of tandem-repeat galectins and domain coordination governs galectin-4 activity in grass carp (Ctenopharyngodon idella).

Galectins are β-galactoside-binding lectins that play essential roles in innate immunity. Among them, tandem-repeat galectins (TrGals), typically composed of two distinct carbohydrate-recognition domains (CRDs) connected by a linker peptide, are well established as key regulators of pathogen recognition and host defense in mammals. However, their structural diversity and immunological functions in teleost fish remain poorly understood. In this study, five TrGals (Gal-4, Gal-8a, Gal-8b, Gal-9, and Gal-9like) were identified in grass carp. Sequence and structural analysis revealed that Gal-8a/b, Gal-9, and Gal-9like possess the canonical two-CRD architecture, whereas Gal-4 uniquely contains four highly similar tandem-repeat domains. All five TrGals were broadly expressed across examined tissues, with predominant expression in the liver. Upon Aeromonas hydrophila infection, Gal-4, Gal-8a, Gal-8b, and Gal-9 were rapidly up-regulated at early time points (3-6 h). To elucidate the functional significance of CRD number, recombinant full-length CiGal-4 (CiGal4-full) and three truncated variants containing one, two, or three CRDs (CiGal4-1CRD, CiGal4-2CRD, and CiGal4-3CRD) were generated and systematically characterized. All recombinant proteins contained the conserved β-sheet structure typical of galectin CRDs. Functional assays revealed that CiGal4-full displayed the strongest growth-inhibitory activity against all tested bacteria, whereas CiGal4-1CRD showed the weakest effect. Notably, CiGal4-2CRD exhibited the most potent bactericidal activity, surpassing the full-length protein, while CiGal4-3CRD showed no further enhancement. CiGal4-full and CiGal4-2CRD showed superior carbohydrate-binding activities compared with the other variants. Collectively, these results reveal that CRD copy number alone does not linearly determine galectin function. Instead, domain organization and conformational coordination are critical for optimizing antimicrobial activity. This study provides new insights into the structure-function relationships and evolutionary diversification of galectins in teleosts and highlights their potential as novel antimicrobial and immunomodulatory agents in aquaculture.

Animals↗

PubMed2006

Generation of three-dimensional hepatocyte/gelatin structures with rapid prototyping system.

Using rapid prototyping technology, three-dimensional (3D) structures composed of hepatocytes and gelatin hydrogel have been formed. This technique employs a highly accurate 3D micropositioning system with a pressure-controlled syringe to deposit cell/biomaterial structures with a lateral resolution of 10 microm. The pressure-activated micro-syringe is equipped with a fine-bore exit needle for which a wide variety of 3D patterns with different arrays of channels (through-holes) were created. More than 30 layers of a hepatocyte/gelatin mixture were laminated into a high spacial structure using this method. The laminated hepatocytes remained viable and performed biological functions in the construct for more than 2 months. The rapid prototyping technology offers potential for eventual high-throughout production of artificial human tissues or organs.

Animals↗

PubMed2006

Tear breakup dynamics: a technique for quantifying tear film instability.

PURPOSE: The purpose of this study was to develop a novel, quantitative measurement of tear film breakup dynamics (TBUD) to study the phenomenon of tear breakup in dry eye and control subjects and its impact on dry eye symptoms. METHODS: Ten control and 10 dry eye subjects completed the Dry Eye (DEQ) and other questionnaires. After the instillation of sodium fluorescein, subjects kept the tested eye open for as long as possible, similar to a staring contest, while tear film breakup was videotaped (S-TBUD). The maximum blink interval (MBI) and tear breakup time (TBUT) were measured from digital movies by a masked observer. Individual frames of movies were converted to gray-scale images, maps of relative tear film fluorescence were generated, and the total area of tear breakup (AB) of the exposed cornea was quantified. RESULTS: On average, dry eye subjects demonstrated a higher AB and shorter TBUT and MBI, but only the AB was significantly different (p = 0.023). Subjects most often used the descriptors stinging and burning to describe their sensations during staring trials. The AB showed a high correlation between eyes and with some DEQ symptom measures. CONCLUSIONS: These methods allow objective quantification and tracking of the phenomenon of tear breakup. Our results suggest that tear breakup stresses the corneal surface, resulting in stimulation of underlying nociceptors. The tear film of dry eye subjects was less stable than controls. They had a larger AB measured from the last video frame before MBI (i.e., just before blinking) than did controls. This perhaps reflects adaptation to the repeated stress of tear instability in dry eye.

Adult↗

PubMed2006

Temporal progression and spatial repeatability of tear breakup.

PURPOSE: This study used image analysis to compare the temporal progression and spatial reoccurrence of the area of tear film breakup (AB) in dry eye and normal subjects. METHODS: Tear breakup was induced in 10 control and 10 dry eye subjects during the Staring Tear Breakup Dynamics (S-TBUD) test, which involves keeping one eye open for as long as possible, termed the maximum blink interval (MBI). Video imaging of tear film fluorescence measured the onset and progression of the AB. AB location and area were mapped. The progression of ABs from the first trial, the rate of tear breakup or dry area growth rate (DAGR), and the overlap of ABs in three successive trials 5 minutes apart were computed by custom MATLAB programs. RESULTS: The final AB before the blink was significantly greater (average, 30.7%+/-12.5% vs. 16.1%+/-9.2%) and the MBI was significantly less (average, 19.5+/-9.0 seconds vs. 56.5+/-38.9 seconds) among dry eye subjects compared with controls (p<0.05, Mann-Whitney U test). The DAGR was four times greater among dry eye subjects, who also showed significantly more tear breakup in the central cornea than controls (p<0.0001, Mann-Whitney U test). When the final image from three successive trials was overlapped, tear breakup occurred more often in the same location in three trials than would be expected by the overlap of independent points. CONCLUSIONS: Structural influences such as the "black line" or corneal lid defects appeared to influence the recurrence of breakup in the same region. The S-TBUD quantitative image analysis technique demonstrates that the tear film of subjects with dry eye continues to rapidly destabilize after an initial first break; thus, a low TBUT was combined with a high DAGR. The central corneal region of subjects with dry eye appeared especially susceptible to increased tear breakup when compared with controls.

Adult↗

PubMed2005

Fabrication of viable tissue-engineered constructs with 3D cell-assembly technique.

We have recently developed an organ manufacturing technique that enables us to form cell/biomaterial complex three-dimensional (3D) architectures in designed patterns. This technique employs a highly accurate 3D micropositioning system with a pressue-controlled syringe to deposit cell/biomaterial structures with a lateral resolution of 10 microm. The pressure-activated micro-syringe is equipped with a fine-bore exit needle using which a wide variety of 3D patterns with different arrays of channels (through-holes) were created. The channels can supply living cells with nutrients and allow removing the cell metabolites. The embedded cells remain viable and perform biological functions as long as the 3D structures are retained. The new technology has the potential for eventual high-throughput production of artificial human tissues and organs.

Animals↗

PubMed2002

[Experimental study on the treatment of corneal melting after alkali burn with GM 6001].

OBJECTIVE: To eva1uate the effect of synthetic inhibitors of matrix metalloproteinases (GM 6001) on the prevention of melting of rabbit corneas after alkali burn. METHODS: Severe and moderate rabbit alkali burns were made by different concentrations of NaOH. Corneas with severe or moderate alkali injuries were topically treated with 400 mg/L or 200 mg/L GM 6001 for 30 days. Vehicle was used as control. All corneas were evaluated for melting, opacity and other pathological changes. RESULTS: After severe alkali burns, all of the 8 corneas of the control group melted in 13 +/- 5 days, and 2 corneas perforated. Only did 2 corneas melt in 19 +/- 4 days after burn and not perforate in 400 mg/L GM 6001 group. The rates of corneal melting and perforation in 400 mg/L GM 6001 group were lower than that of the control (P < 0.05), and the initial time of melting was later than that of the control (P < 0.0l). After moderate alkali burn, all of the 6 corneas of control melted in 14 +/- 6 days, and 1 cornea perforated. Only did 2 of 200 mg/L GM 6001 treated corneas melt in 19 +/- 4 days without perforation after burn. The rate of corneal melting and the degree of corneal opacity were lower in 200 mg/L GM 6001 treated than that of the control, the difference being significant (P < 0.0l). Histologic section of GM 6001 treated corneas revealed much less collagen fiber destruction and inflammatory cell infiltration than that of the control. CONCLUSION: GM 6001 not only can prevent and delay the corneal melting after alkali burn, but also can reduce the destruction of corneal collagen fibers and infiltration of inflammatory cells in the corneal tissue.

Alkalies↗