Biomedical subjects

Bin Lin

Publications and source records attributed to Bin Lin.

At least 19 recordsLinked to original sources

PubMed2026

Generation of a New Immunodeficient Rat Model of Retinal Degeneration With LSL TdTomato Reporter and TdTomato-Pcp2 Expression.

PURPOSE: The purpose of this study was to develop a fluorescently labeled immunodeficient retinal degenerate (RD) rat model for studying photoreceptor degeneration and transplant-host connectivity using the Cre-lox system. METHODS: We developed gene constructs for CAG-LSL-TdTomato (expressing floxed TdTomato) and Pcp2-Cre (marker for ON-bipolar cells) that were injected into rat embryos. The LSL TdTomato reporter strain, created on immunodeficient RhoS334ter-3 rats (RRRC #539), was bred to homozygosity (strain SD-Foxn1rnuTg((Rho-S334X)3,CAG-TdTomato)1010Mjsuc, RRRC #1055, "RNT"). The gene construct Pcp2-Cre was injected into Long-Evans (LE) rat embryos, resulting in two Pcp2-cre founders (strain PCP2 Cre-1105 RKI, "Pcp2"), with targeted and targeted/random insertion of the transgene. F1 offspring were bred to homozygosity and immunodeficiency. To test whether TdTomato expression can be induced in "RNT" rats expressing floxed TdTomato, retinal explants of P9 "RNT" rats were exposed to AAV-PHP.eB-hSyn-myc-Cre (AAV-Syn-Cre) virus. Homozygous rats of both strains ("RNT" and Pcp2-Cre) were crossbred to generate RD TdTomato-Pcp2 ("RTP") rats. Retinas were stained for various retinal markers. GFP-expressing rat retinas were transplanted to 6-week-old "RTP" rats and analyzed after 37 and 77 days. RESULTS: AAV-Syn-Cre induced TdTomato expression in "RNT" retinas. TdTomato-Pcp2 RD rats developed RD similar to the original Rho S334ter-3 rats. Retinas with targeted Pcp2-Cre insertion showed TdTomato in retinal interneurons, overlapping with Pcp2-staining ON bipolar cells, and cones. Retinas with random Pcp2-Cre insertion exhibited additional TdTomato in many other cells. Pcp2-TdTomato expression defined transplant-host boundaries. CONCLUSIONS: We created a unique RD rat model for studying retinal transplant connectivity which can also be used to generate RD rats with other cell-specific labels. TRANSLATIONAL RELEVANCE: This newly created rat is useful for cell therapy and retinal degeneration studies.

Animals↗

PubMed2006

Populations of wide-field amacrine cells in the mouse retina.

We surveyed wide-field amacrine cells in the mouse, using a large series of retinas from a transgenic strain that expresses the green fluorescent protein (GFP) in isolated retinal cells. Wide-field cells were present in surprising diversity and number. They formed groups that could be defined by arbor depth, arbor size, and soma size. By conventional criteria, these populations of cells make up 11 amacrine cell "types." Five additional types have been reported by others in the mouse. Roughly two-thirds of the wide-field amacrine cells are axon-bearing cells, which have separate dendritic and axonal arbors. The axonal arbor of a single cell sometimes covers the majority of the retinal surface. The axon-bearing cells appear to be centrifugally conducting neurons similar to those studied electrophysiologically in some other species. Although they are classified as independent morphological types, it seems likely that their physiological functions represent variations on a single organizational plan. These cells are present at every level of the inner plexiform layer, which suggests that they affect most of the mouse retina's final outputs to the brain and, by implication, almost all visual function.

Amacrine Cells↗

PubMed2006

Hemopressin, a hemoglobin fragment, dilates the rat systemic vascular bed through release of nitric oxide.

The present study was undertaken to investigate the effects of intravenous (i.v.) administration of rat hemopressin (rHP), 30-1000 microg/kg, on systemic arterial pressure (SAP), cardiac output (CO) and systemic vascular resistance (SVR) in the anesthetized rat. Bolus i.v. injections of rHP produced mild decreases in SAP that were dose-dependent. Since CO was not altered, the decreases in SAP reflect reductions in SVR. The systemic vasodilator response to rHP was not subject to tachyphylaxis. The systemic vasodilator response to rHP was abolished by L-nitro-arginine methylester (L-NAME) but was not altered by meclofenamate. In addition, rHP lacked direct contractile and relaxant activity on isolated rat aortic rings (AA) and pulmonary arterial rings (PA). The present data suggest rHP dilates the rat systemic vascular bed through the endogenous release of nitric oxide (NO) independent of the formation of cyclooxygenase products including prostacyclin. It is possible rHP acts as an endogenous vasodilator substance to regulate local blood flow during clinical states of altered red cell turnover, microvascular disease and hemolysis.

Animals↗

PubMed2006

Acute phase response in zebrafish upon Aeromonas salmonicida and Staphylococcus aureus infection: striking similarities and obvious differences with mammals.

Zebrafish has emerged as a valuable model for immunological studies. However, little is known about the overall picture of its immune response to infectious pathogens. Here we present the first systematic study of its immune response to Aeromonas salmonicida and Staphylococcus aureus, a Gram-negative and a Gram-positive bacteria, respectively. Genes induced upon infection were identified with suppression subtractive hybridization, with many of them encoding acute phase proteins (APPs). When compared with mammals, striking similarities and obvious differences have been observed. Both similar APPs (SAA, hepcidin and haptoglobin, etc.) and a similar system for the induction of APPs (which involves the TLRs, pro-inflammatory cytokines and C/EBPs) were identified, implying evolutionary conserved mechanisms among fish and mammals. Some novel APPs were also discovered, suggesting different immune strategies adopted by fish species. Among which, LECT2 was induced by up to 1000-fold upon infection, shedding new lights on the function of this gene. Our results constitute the first demonstration of a similar while different immune response in zebrafish and open new avenues for the investigation of evolutionary conserved and fish specific mechanisms of innate immunity.

Acute-Phase Reaction↗

PubMed2006

Integrin-driven actin polymerization consolidates long-term potentiation.

Long-term potentiation (LTP), like memory, becomes progressively more resistant to disruption with time after its formation. Here we show that threshold conditions for inducing LTP cause a rapid, long-lasting increase in polymerized filamentous actin in dendritic spines of adult hippocampus. Two independent manipulations that reverse LTP disrupted this effect when applied shortly after induction but not 30 min later. Function-blocking antibodies to beta1 family integrins selectively eliminated both actin polymerization and stabilization of LTP. We propose that the initial stages of consolidation involve integrin-driven events common to cells engaged in activities that require rapid morphological changes.

Actins↗

PubMed2006

An ancient balanced polymorphism in a regulatory region of human major histocompatibility complex is retained in Chinese minorities but lost worldwide.

The coding regions of many of the major histocompatibility complex (MHC) (human leukocyte antigen [HLA] in humans) molecules are believed to be subject to balancing selection. But it is less certain whether the regulatory regions of such coding sequences are also subject to the same type of selection. Here, we studied the polymorphism of the regulatory regions of the HLA-DPA1 and HLA-DPB1 genes among ethnic minorities in southwestern China. Phylogenetic analysis revealed two deep clades >10 million years old. There is almost complete linkage disequilibrium between the regulatory and coding regions of HLA-DPA1, which hints at coadaptive balancing selection on the entire region. Thus, the molecular mechanism of balancing selection in MHC may involve expression modulation in addition to coding-region polymorphisms. Although the frequency of clade II is >30% in some ethnic minorities, it decreases to <5% among southern Han Chinese and vanishes among Europeans. As suspected, some ancient balanced polymorphisms, lost in major populations, still exist in isolated ethnicities. These isolated populations may thus contribute disproportionately to the total diversity of modern humans.

Amino Acid Sequence↗

PubMed2006

[Allogenous bone plate reconstructing spinal channel and grafting in treatment of thoracolumbar burst fracture with paraplegia].

OBJECTIVE: To evaluate the method of the allogenous bone plate reconstructing the spinal channel and grafting in treatment of thoracolumbar burst fracture with paraplegia. METHODS: Thirty-six patients with thoracolumbar burst fracture with paraplegia were included in this study. Their ages ranged from 18 to 56 (average, 38). The vertebral injury involved T11 in 3 patients, T12 in 10 patients, L1 in 14 patients, L2 in 7 patients, and L3 in 2 patients. Neurological deficits were classified by the Frankel grading. There were 9 patients in grade A, 11 patients in grade B, 13 patients in grade C, and 3 patients in grade D. All the patients were treated with the anterior approach, decompression of the spinal channel, interbody graft, and internal fixation. The grafting materials consisted of the allogenous femoral bone plate that was decreased in advance and implanted in the intervertebral posterior region, with cut ribs and bone mills during the decompression. RESULTS: Postoperative CT scanning showed clearance of the spinal cord compression and expansion of the spine channel. During the follow-up period averaged 2 years, almost all the patients showed an improvement in the neurological function. Spinal fusion occurred in 32 patients. There was no screw loosened or broken. Only 1 patient failed to achieve the fusion. CONCLUSION: The anterior approach, allograft bone plate reconstructing the spine channel is a safe and effective method in treatment of the thoracolumbar burst fracture with paraplegia, which may be a replacement of the autogenous iliac bone graft.

Adolescent↗

PubMed2005

Mechanisms of late-onset cognitive decline after early-life stress.

Progressive cognitive deficits that emerge with aging are a result of complex interactions of genetic and environmental factors. Whereas much has been learned about the genetic underpinnings of these disorders, the nature of "acquired" contributing factors, and the mechanisms by which they promote progressive learning and memory dysfunction, remain largely unknown. Here, we demonstrate that a period of early-life "psychological" stress causes late-onset, selective deterioration of both complex behavior and synaptic plasticity: two forms of memory involving the hippocampus, were severely but selectively impaired in middle-aged, but not young adult, rats exposed to fragmented maternal care during the early postnatal period. At the cellular level, disturbances to hippocampal long-term potentiation paralleled the behavioral changes and were accompanied by dendritic atrophy and mossy fiber expansion. These findings constitute the first evidence that a short period of stress early in life can lead to delayed, progressive impairments of synaptic and behavioral measures of hippocampal function, with potential implications to the basis of age-related cognitive disorders in humans.

Age Factors↗

PubMed2005

Sequence variations in the transcriptional regulatory region and intron1 of HLA-DQB1 gene and their linkage in southern Chinese ethnic groups.

Sequence polymorphism in the transcriptional regulatory region extending to intron1 (DQRRI1) of HLA-DQB1 gene, and their haplotypic distributions were investigated in southern Chinese populations. We cloned and sequenced a 1.1-kb segment containing the transcriptional regulatory region, exon1, and partial intron1 of HLA-DQB1 gene of 37 individuals from nine different ethnic groups in southern China. A high-density map of 162 polymorphisms, including 152 single nucleotide polymorphisms (SNPs) and 10 insertion-deletion polymorphisms, was revealed. By comparing these data with SNPs deposited in dbSNP database in National Center for Biotechnology Information and polymorphisms that have been reported, 66 polymorphisms were firstly reported. A total of 16 different haplotypes were detected based on these 162 polymorphisms. The distribution of 16 alleles of DQRRI1 as well as their linkage with DQB1 exon2 alleles was also investigated based on the population study and phylogenetic analysis. Tight linkage between these two regions were discovered, as each of DQB1*02, DQB1*03, DQB1*04, DQB1*05, and DQB1*06 alleles was seen to be linked with specific DQRRI1 allele. Our study showed different pattern of transcriptional regulatory region, exon1, and intron1 of different DQB1 alleles.

Alleles↗

PubMed2005

Different functional types of bipolar cells use different gap-junctional proteins.

Rod signals are transmitted to ON retinal ganglion cells by means of gap junctions between AII amacrine cells and ON bipolars. The AII amacrine cells are known to express connexin36 (Cx36), but previous studies of Cx36 in ON cone bipolars have been ambiguous. Here, we studied bipolar cells in a transgenic mouse line that expresses high levels of green fluorescent protein (GFP) in one type of ON cone bipolar cell. We found strong Cx36 immunostaining in the axon terminals of the GFP-labeled type 357 bipolar cells in both vertical sections and whole mounts of the retina. This finding was confirmed by single-cell immunostaining and single-cell reverse transcription-PCR (RT-PCR). As reported previously (Maxeiner et al., 2005), Cx45 was found in some ON bipolar cells, but RT-PCR showed Cx36 and not Cx45 to be expressed by the type 357 bipolar cells. Some of the remaining GFP-negative bipolar cells expressed Cx45 but not Cx36. It appears that different types of ON cone bipolar cells express different connexins at their gap junctions with AII amacrine cells.

Amacrine Cells↗

PubMed2005

Solubility of sodium soaps in aqueous salt solutions.

The solubility of sodium soaps in dilute aqueous salt solutions has been systematically investigated by direct visual phase behavior observations. The added electrolytes, including simple inorganic salts and bulky organic salts, influence the solubility of sodium soaps in water, as represented by the varied soap Krafft point. Two inorganic salts, sodium chloride and sodium perchlorate, demonstrate a "salting-out" property. On the other hand, tetraalkylammonium bromides show an excellent ability to depress the soap Krafft point and enhance the soap solubility in water. With increasing the tetraalkylammonium ionic size, the degree of "salting-in" of soaps in water increases. However, solubility of pure tetraalkylammonium bromide in water decreases as the length of the alkyl chains increases. Furthermore, in the ternary water-tetrapentylammonium bromide (TPeAB)-sodium myristate (NaMy) system, we observed an upper cloud point phenomenon, which greatly shrinks the 1-phase micellar solution region in the phase diagram. This miscibility gap, together with the organic salt solubility limitation, restricts the use of tetraalkylammonium bromides with alkyl chains longer than 4 carbon atoms as effective soap solubility enhancement electrolytes. We also found that for sodium soap with a longer hydrocarbon chain, more tetrabutylammonium salt is required to reduce the soap Krafft point to room temperature.

Journal Article↗

PubMed2005

Long-term potentiation is impaired in middle-aged rats: regional specificity and reversal by adenosine receptor antagonists.

Memory loss in humans begins early in adult life and progresses thereafter. It is not known whether these losses reflect the failure of cellular processes that encode memory or disturbances in events that retrieve it. Here, we report that impairments in hippocampal long-term potentiation (LTP), a form of synaptic plasticity associated with memory, are present by middle age in rats but only in select portions of pyramidal cell dendritic trees. Specifically, LTP induced with theta-burst stimulation in basal dendrites of hippocampal field CA1 decayed rapidly in slices prepared from 7- to 10-month-old rats but not in slices from young adults. There were no evident age-related differences in LTP in the apical dendrites. Both the adenosine A1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine and a positive AMPA receptor modulator (ampakine) offset age-related LTP deficits. Adenosine produced greater depression of synaptic responses in middle-aged versus young adult slices and in basal versus apical dendrites. These results were not associated with variations in A1 receptor densities and may instead reflect regional and age-related differences in adenosine clearance. Pertinent to this, brief applications of A1 receptor antagonists immediately after theta stimulation fully restored LTP in middle-aged rats. We hypothesize that the build-up of extracellular adenosine during theta activity persists into the postinduction period in the basal dendrites of middle-aged slices and thereby activates the A1 receptor-dependent LTP reversal effect. Regardless of the underlying mechanism, the present results provide a candidate explanation for memory losses during normal aging and indicate that, with regard to plasticity, different segments of pyramidal neurons age at different rates.

Aging↗

PubMed2005

Theta stimulation polymerizes actin in dendritic spines of hippocampus.

It has been proposed that the endurance of long-term potentiation (LTP) depends on structural changes entailing reorganization of the spine actin cytoskeleton. The present study used a new technique involving intracellular and extracellular application of rhodamine-phalloidin to conventional hippocampal slices to test whether induction of LTP by naturalistic patterns of afferent activity selectively increases actin polymerization in juvenile to young adult spines. Rhodamine-phalloidin, which selectively binds to polymerized actin, was detected in perikarya and proximal dendrites of CA1 pyramidal cells that received low-frequency afferent activity but was essentially absent in spines and fine dendritic processes. Theta pattern stimulation induced LTP and caused a large (threefold), reliable increase in labeled spines and spine-like puncta in the proximal dendritic zone containing potentiated synapses. The spines frequently occurred in the absence of labeling to other structures but were also found in association with fluorescent dendritic processes. These effects were replicated (>10-fold increase in labeled spines) using extracellular applications of rhodamine-phalloidin. Increases in labeling appeared within 2 min, were completely blocked by treatments that prevent LTP induction, and occurred in slices prepared from young adult rats. These results indicate that near-threshold conditions for inducing stable potentiation cause the rapid polymerization of actin in mature spines and suggest that the effect is both sufficiently discrete to satisfy the synapse-specificity rule of LTP as well as rapid enough to participate in the initial stages of LTP consolidation.

Actins↗

PubMed2005

Single nucleotide polymorphisms in the regulatory regions of the HLA-DRB-expressed genes.

DRB genes encode proteins that play an important role in the immune response, and their expressional regulation is crucial to the immune reaction. Sequence variation at the regulatory region can directly affect the gene expression level. The aim of the present study was to use Chinese samples to investigate the variation in the regulation region of the human leukocyte antigen (HLA)-DRB-expressed genes. Seventy- one single nucleotide polymorphisms (SNPs) were found in the four HLA-DRB-expressed genes. By comparing these data with SNPs in the U.S. National Center for Biotechnology Information dbSNP database, 69 SNPs (97.2%) were found to be novel. In addition, two genetic variations of insertion-deletion polymorphisms were discovered within the regulatory region of HLA-DRB1 gene. These polymorphisms can be used as resources of markers for association studies of complex diseases, for assessment of individual predisposition to diseases, and as research markers for population genetics and evolution.

Base Sequence↗

PubMed2005

Synaptic contacts between an identified type of ON cone bipolar cell and ganglion cells in the mouse retina.

We surveyed the potential contacts between an identified type of bipolar cell and retinal ganglion cells in the mouse. By crossing two existing mouse strains (line 357 and line GFP-M), we created a double transgenic strain in which GFP is expressed by all members of a single type of ON cone bipolar cell and a sparse, mixed population of retinal ganglion cells. The GFP-expressing bipolar cells appear to be those termed CB4a of Pignatelli & Strettoi [(2004) J. Comp. Neurol., 476, 254-266] and type 7 of Ghosh et al. [(2004) J. Comp. Neurol., 469, 70-82 and J. Comp. Neurol., 476, 202-203]. The labelled ganglion cells include examples of most or all types of ganglion cells present in the mouse. By studying the juxtaposition of their processes in three dimensions, we could learn which ganglion cell types are potential synaptic targets of the line 357 bipolar cell. Of 12 ganglion cell types observed, 10 types could be definitively ruled out as major synaptic targets of the line 357 bipolar cells. One type of monostratified ganglion cell and one bistratified cell tightly cofasciculate with axon terminals of the line 357 bipolar cells. Double labelling for kinesin II demonstrates colocalization of bipolar cell ribbons at the sites of contact between these two types of ganglion cell and the line 357 bipolar cells.

Animals↗

PubMed2005

Geobacteraceae community composition is related to hydrochemistry and biodegradation in an iron-reducing aquifer polluted by a neighboring landfill.

Relationships between community composition of the iron-reducing Geobacteraceae, pollution levels, and the occurrence of biodegradation were established for an iron-reducing aquifer polluted with landfill leachate by using cultivation-independent Geobacteraceae 16S rRNA gene-targeting techniques. Numerical analysis of denaturing gradient gel electrophoresis (DGGE) profiles and sequencing revealed a high Geobacteraceae diversity and showed that community composition within the leachate plume differed considerably from that of the unpolluted aquifer. This suggests that pollution has selected for specific species out of a large pool of Geobacteraceae. DGGE profiles of polluted groundwater taken near the landfill (6- to 39-m distance) clustered together. DGGE profiles from less-polluted groundwater taken further downstream did not fall in the same cluster. Several individual DGGE bands were indicative of either the redox process or the level of pollution. This included a pollution-indicative band that dominated the DGGE profiles from groundwater samples taken close to the landfill (6 to 39 m distance). The clustering of these profiles and the dominance by a single DGGE band corresponded to the part of the aquifer where organic micropollutants and reactive dissolved organic matter were attenuated at relatively high rates.

Biodegradation, Environmental↗

PubMed2005

[Comparison and improvement in the methods of establishing animals model of experimental chronic sinusitis in rabbits].

OBJECTIVE: To compare and improve the methods of establishing animal model of experimental chronic sinusitis in rabbits . METHODS: Sixty-six New Zealand white rabbits were divided into seven groups: control group, sham-operation group I, sham-operation group II, bacteria inoculation group, ostia-blocked group, ostia-blocked and bacteria inoculation group, incomplete ostium blocked and set-cotton group. The animals were examined by the methods of histology and bacteriology after 42 days. RESULTS: The positive rate of chronic inflammation in ostium blocked group was 80%, inoculated staphylococcus group was 100%, incomplete ostium blocked and set-cotton group was 100%, and the other groups were 0%. All infected sinuses displayed signs of moderate or severe chronic inflammation. The cultivated bacteria were mainly opportunistic pathogens. The probability of having abscess in maxillary sinus was high in ostia-blocked and bacteria inoculation group. CONCLUSIONS: The method of incomplete ostium blockage and set cotton can establish stable chronic sinusitis model, it is a simple and perfect method.

Animals↗

PubMed2004

Crystallization of silver stearate from sodium stearate dispersions.

Silver carboxylates, the common silver source used for photothermographic imaging materials, are normally obtained from the reaction between sodium soap (e.g., sodium stearate) and silver nitrate. They form platelet-like crystals with a lamellar structure in water at room temperature. Light microscopy investigations reveal that the formation of silver stearate (AgSt) crystals follows a diffusion-controlled mechanism. The reaction between the sodium soap and silver nitrate preferentially occurs in solution rather than on the soap fiber solid interface. Cryogenic transmission electron microscopy, together with an on-the-grid reaction technique, provides a useful tool to directly image silver stearate microstructures at the initial stages of AgSt precipitation. The AgSt reaction product first forms particles about 5 nm in size, which is similar to the d-spacing of final AgSt crystals. Those particles aggregate to produce larger and loosely packed embryonic crystals, the precursors to the ultimate silver stearate crystals.

Crystallization↗