Biomedical subjects

K Huang

Publications and source records attributed to K Huang.

At least 37 records · Page 2Linked to original sources

PubMed2001

[Progress on evaluation criterion of wound healing].

OBJECTIVE: To set up some objective and accurate criteria to evaluate wound healing. METHODS: Documents about wound healing were reviewed and summarized in detail. RESULTS: Wound healing rate, wound healing time, histopathology analysis, quantity assay of macrophage, determination of hydroxyproline, proliferation of cell, assay of DNA contents and circle of cells, level of transforming growth factor-alpha, levels of interleukin-1, interleukin-6 and tumor necrosis factor, assay of keratinocyte collagenase-1, level of fibroblast growth factor receptor-1, level of monocyte chemoattractant protein-1 and level of keratinocyte plasminogen activator inhabitor type 2 were selected as the evaluation criteria of wound healing. CONCLUSION: Wound healing rate, wound healing time and histopathology analysis are direct and efficient criteria of wound healing.

Evaluation Studies as Topic↗

PubMed2001

[Allogeneic peripheral blood stem cell transplantation for 3 patients with beta-thalassemia major and 1 patient with congenital idiopathic haemolytic anemia].

OBJECTIVE: To examine the feasibility of allogeneic peripheral blood stem cell transplantation (Allo-PBSCT) for the hereditary haemolytic anemia (HHA). METHODS: Allo-PBSCTs were performed on 3 patients with beta-thalassemia major and 1 patient with congenital idiopathic haemolytic anemia by the HLA-identical siblings' donors or 1 locus-mismatch parent. The harvested stem cell contained nucleated cells (4.7-14.4) X 10(8)/kg recipient weight, CD(34) (+) CD(38)(-) cells(4.8-32.9) X 10(6)/kg and colony-forming-unit-granulocyte-macrophages (CFU-GM)(3.22-9.8) X 10(5)/kg. The conditioning regimen consisted of busulfan, cyclophosphamide, melphalan, thiotepa, fludarabine and antithymocyte globulin (ATG). RESULTS: All patients were engrafted and accomplished with the acute graft-versus-host disease (aGVHD). A patient had the controlled chronic GVHD. Three patients are survivals with ex-anemia; their Hb levels have been maintaining normality without transfusion. One died of the hepatic veno-occlusive disease. CONCLUSION: Allo-PBSCT is an effective and a new way to treat beta-thalassemia major and congenital idiopathic haemolytic anemia.

Anemia, Hemolytic, Congenital↗

PubMed2001

Effects of extrinsic positive end-expiratory pressure on work of breathing in patients with chronic obstructive pulmonary disease.

OBJECTIVE: To investigate the effects of extrinsic positive end-expiratory pressure (PEEPe) on work of breathing in patients with chronic obstructive pulmonary disease (COPD) and their corresponding mechanism. METHODS: Ten ventilated patients with COPD were included in the study. A Bicore CP-100 pulmonary monitor (Bicore Monitoring System, USA) was used for monitoring respiratory mechanics. First, dynamic intrinsic positive end-expiratory pressure (PEEPi, dyn) was measured when PEEPe was zero, which was called PEEPi, dynz. Then the PEEPe was set randomly at 0%, 40%, 60%, 80% and 100% of PEEPi, dynz respectively. Pulmonary mechanics and other parameters (heart rate, blood pressure and blood gas analysis) were measured 30 minutes after the level of PEEPe was changed. RESULTS: Work of breathing patient (WOBp), pressure time product, difference of esophageal pressure and PEEPi, dyn decreased significantly when PEEPe was applied, and continued decreasing as PEEPe was increased. Work of breathing ventilator increased significantly when PEEPe was increased to 80% and 100% of PEEPi, dynz. Significantly positive linear correlation was found between the changes in WOBp and in PEEPi, dyn. CONCLUSIONS: WOBp decreases gradually as PEEPe is increased. WOBp decreases by narrowing the difference between the alveolus pressure and the central airway pressure at the end of expiration when PEEPe is applied.

Aged↗

PubMed2001

Effects of extrinsic positive end-expiratory pressure on cardiopulmonary function in patients with chronic obstructive pulmonary disease.

OBJECTIVE: To choose one optimal extrinsic positive end-expiratory pressure (PEEPe) for ventilated patients with chronic obstructive pulmonary disease (COPD) and to compare two methods for choosing the optimal level of PEEPe. METHODS: Ten ventilated patients with COPD were included in the study. First, static intrinsic positive end-expiratory pressure (PEEPi, st) was measured when PEEPe was zero, and the PEEPi, st was called PEEPi, stz. PEEPe at 0%, 40%, 50%, 60%, 70%, 80%, 90% and 100% of PEEPi, stz, respectively, were applied randomly. Respiratory mechanics, hemodynamics, and oxygen dynamics were recorded 30 minutes after the level of PEEPe was changed. RESULTS: When PEEPe was not higher than 80% of PEEPi, stz, no measurement changed significantly. When PEEPe was increased to 90% and 100% of PEEPi, stz, PEEPi, st, peak inspiratory pressure, plateau pressure, pulmonary capillary wedge pressure and central venous pressure increased significantly, P < 0.01. Cardiac output and left ventricular work index decreased significantly, P < 0.01. Oxygen delivery decreased significantly, P < 0.05. When PEEPe was increased to 100% of PEEPi, stz, the right ventricular work index decreased significantly, P < 0.05. CONCLUSION: Eighty percent of PEEPi, stz was the upper limit of PEEPe. The results of the two methods used to set the level of PEEPe were identical.

Aged↗

PubMed2001

[The effects of extrinsic positive end-expiratory pressure on work of breathing in patients with chronic obstructive pulmonary disease].

OBJECTIVE: To study the effect of extrinsic positive end-expiratory pressure(PEEPe) on work of breathing in chronic obstructive pulmonary disease (COPD) patients and its mechanism. METHODS: 10 ventilated patients [4 males and 6 females with mean age of (70.1 +/- 5.5) years] with exacerbation of COPD were admitted into the study. All the patients' cardiopulmonary functions were stable, and they could receive pressure support ventilation (PSV). Patients with sever heart dysfunction, hepatic dysfunction, renal dysfunction or fever were ruled out. Each patient had an esophagus balloon pressure sensor inserted, and the esophagus balloon was properly positioned using "occlusion test". Flow sensor was placed at the end of tracheal tube opening. Then esophagus balloon pressure sensor and flow sensor were connected with Bicore CP-100 pulmonary monitor. Dynamic intrinsic positive end-expiratory pressure (PEEPi, dyn), difference of esophagus pressure (dPes), work of breathing patient (WOBp), work of breathing ventilator (WOBv), pressure time product (PTP), tidal volume (Vt), respiratory rate (RR), minute ventilation (MV), peak inspiratory flow rate (PIFR), peak expiratory flow rate (PEFR), expiratory airway resistance (Rawe), fraction of inspiration (Ti/Ttot) and so on were measured. PEEPi,dyn was measured by esophagus balloon technique. Electrocardiogram and noninvasive blood pressure modes were added to HP M1165A monitor. Heart rate (HR) and blood pressure (BP) were also measured. Arterial blood was analyzed to measure pH, partial pressure of oxygen in arterial blood (PaO(2)), partial pressure of carbon dioxide in arterial blood (PaCO(2)) and saturation of arterial blood oxygen (SaO(2)). At first, PEEPi, dyn was measured when PEEPe was zero, which was called PEEPi, dynz and was set as baseline. Then PEEPe was set randomly, which was 0%, 40%, 60%, 80% and 100% of PEEPi, dynz respectively. Other parameters remained stable. All the indexes were measured 30 minutes after the level of PEEPe was changed. RESULTS: WOBp decreased as PEEPe increased, from (1.08 +/- 0.49) J/L of PEEPe-0% of PEEPi,dynz to (0.57 +/- 0.32) J/L of PEEPe-100% of PEEPi, dynz, and significant difference was found between each level of PEEPe and the baseline (P < 0.01). But we didn't find significant difference between PEEPe-80% of PEEPi,dynz and PEEPe-100% of PEEPi, dynz. WOBv increased significantly as PEEPe increased, from (1.50 +/- 0.47) J/L of PEEPe-0% of PEEPi, dynz to (1.82 +/- 0.56) J/L of PEEPe-80% of PEEPi, dynz and (1.85 +/- 0.48) J/L of PEEPe-100% of PEEPi,dynz(P < 0.01). The total WOB (WOBp + WOBv) remained steady. PTP trended to decrease, from (153.6 +/- 76.8) cm H(2)O x s x m(-1) of PEEPe-0% of PEEPi, dynz to (86.9 +/- 45.9) cm H(2)O x s x m(-1) of PEEPe-100% of PEEPi, dynz; the difference of PTP between PEEPe-40% of PEEPi,dynz and PEEPe-0% of PEEPi, dynz was significant(P < 0.05), the differences between other levels of PEEPe and PEEPe-0% of PEEPi, dynz were very significant (P < 0.01), but no significant difference was found between PEEPe-80% of PEEPi, dynz and PEEPe-100% of PEEPi, dynz. PEEPi,dyn also decreased significantly as PEEPe increased, from (7.70 +/- 1.42) cm H(2)O of PEEPe-0% of PEEPi, dynz to (2.10 +/- 0.57) cm H(2)O of PEEPe-100% of PEEPi, dynz, very significant differences were found between each level of PEEPe and the baseline (P < 0.01). Significant positive linear correlation was found between DeltaWOBp and DeltaPEEPi, dyn were(r = 0.609, P < 0.01, n = 10). dPes decreased as PEEPe increased, from (15.20 +/- 4.16) cm H(2)O of PEEPe-0% of PEEPi, dynz to (8.20 +/- 4.13) cm H(2)O of PEEPe-100% of PEEPi, dynz, and very significant differences were found between each level of PEEPe and the baseline (P < 0.01). But the difference between PEEPe-80% of PEEPi, dynz and PEEPe-100% of PEEPi, dynz wasn't significant, even dPes of PEEPe-100% of PEEPi, dynz was higher than that of PEEPe-80% of PEEPi, dynz. Vt didn't change markedly. RR, MV and f/Vt increased slightly. Both PIFR and PEFR didn't change markedly. At the same time, HR, BP and blood gas analysis were investigated, but no significant change was found. CONCLUSION: PEEPe can reduce WOBp significantly and improve the coordination between the patient and ventilator. It is shown that decrement of pressure difference between alveolar and central airway leads to decrement of WOBp.

Aged↗

PubMed2001

[The achievement of industrialized healthy aquatic breeding of hippocampus and its application prospects].

The artificial industrialized aquatic breeding of Hippocampus, which is a kind of Chinese medicinal marine material, has been achieved in the artificial aquatic breeding base of Hippocampus of Guangdong Richvast Group Company since 1983. This article reported part of the achievements of the large-scale artificial aquatic breeding experiments. The prospects for the research and application of Hippocampus as health foods and drugs were also analyzed.

Animals↗

PubMed2001

[Study on immunonodulating activities of enzymolyzed loach protein].

The immunomodulating activities of enzymolyzed loach protein in mice were investigated by regular methods for immunology evaluation. The doses of enzymolyzed loach protein were 0.1, 0.2, 0.4 g.kg-1 bw, which were 5, 10, 20 times respectively as large as the recommended daily intake(0.02 g.kg-1 bw). After being successively fed with enzymolyzed loach protein at given doses for 30 days by ig respectively, the mice were detected by immunomodulation tests. The results indicated that enzymolyzed loach protein had significant modulating effects on all of test indexes and suggested it had apparent immunomodulating activities in mice. Based on the results described above, we speculate that the enzymolyzed loach protein may have immunomodulating functions and can enhance the immunity of body.

Adjuvants, Immunologic↗

PubMed2001

Biorheological characteristics of skin after expansion.

This study investigated the changes in biorheological characteristics of skin after expansion. Expanders were implanted into the back of eight adult dogs, and after an eight-week expansion the expanded and the non-expanded control skins were transferred to an adjacent site. The expanded specimens and their controls were obtained at 3, 6, 12 and 24 weeks after transfer, and their biorheological characteristics and histological changes were studied. The characteristics of the stress-relaxation, the stress-strain relationship and tensile strength of the expanded and control specimens were measured. The tests demonstrated that during the initial stage after transfer, the biorheological properties of experimental specimens differed significantly from those of their controls. However, the differences between expanded and control specimens began to lessen gradually with increasing recovery time. When the recovery time reached 24 weeks or longer, the experimental skin exhibited the same mechanical properties as the control skin. Histological examination of expanded specimens showed thickened epidermis and thinned dermis. But there were no significant histological differences between expanded skins and their controls after 24 weeks.

Animals↗

PubMed2001

[Studies on the ribosomal RNA gene(rDNA) of a microsporidium isolated from Pieris rapae L].

Nuclotide sequence (1205 bp) of small subunit ribosomal RNA (SSUrDNA) of a microsporidium isolated from Pieris rapae L. (abbr:MPr) was specifically amplified by polymerase chain reaction (PCR). Another fragment of 657 bp downstream of MPr SSUrDNA 3'end was amplified with two other primers. Within this 657 bp fragment, the putative 3'terminus of MPr SSUrDNA and the extreme 5' of large subunit ribosomal RNA gene. (LSUrDNA) were identified, which situated at base 145, 146-186 and 187, respectively. Then the full sequence of MPr ssurDNA is 1245 bp. Its GC content was also nearly 34%. The ITS region (internal transcribed spacer), positioned between the ssu and LSUrRNA genes, was found to be 41 bp in length. The LSUrDNA 580r region of MPr is 470 bp, longer than 437 bp of Nosema apis, 447 bp of Nosema algerae. The secondary structure of MPr SSUrRNA was constructed. These analyses of MPr rRNA gene contributed to the somewhat limited microsporidian taxonomic classification based on morphology.

Animals↗

PubMed2000

Solution structure of the interacting domains of the Mad-Sin3 complex: implications for recruitment of a chromatin-modifying complex.

Gene-specific targeting of the Sin3 corepressor complex by DNA-bound repressors is an important mechanism of gene silencing in eukaryotes. The Sin3 corepressor specifically associates with a diverse group of transcriptional repressors, including members of the Mad family, that play crucial roles in development. The NMR structure of the complex formed by the PAH2 domain of mammalian Sin3A with the transrepression domain (SID) of human Mad1 reveals that both domains undergo mutual folding transitions upon complex formation generating an unusual left-handed four-helix bundle structure and an amphipathic alpha helix, respectively. The SID helix is wedged within a deep hydrophobic pocket defined by two PAH2 helices. Structure-function analyses of the Mad-Sin3 complex provide a basis for understanding the underlying mechanism(s) that lead to gene silencing.

Amino Acid Sequence↗

PubMed2000

Function of CD3 epsilon-mediated signals in T cell development.

The T cell antigen receptor (TCR) and pre-TCR complexes are composed of multiple signal-transducing subunits (CD3 gamma, CD3 delta, CD3 epsilon, and zeta) that each contain one or more copies of a semiconserved functional motif, the immunoreceptor tyrosine-based activation motif (ITAM). Although biochemical studies indicate that individual TCR-ITAMs may bind selectively or with different affinity to various effector molecules, data from other experiments suggest that at least some ITAMs are functionally equivalent. In this study, we examined the role of CD3straightepsilon ITAM-mediated signals in T cell development by genetically reconstituting CD3 epsilon-deficient mice with transgenes encoding either wild-type or ITAM-mutant (signaling defective) forms of the protein. The results demonstrate that signals transduced by CD3 epsilon are not specifically required for T cell maturation but instead contribute quantitatively to TCR signaling in a manner similar to that previously observed for zeta chain. Unexpectedly, analysis of TCR-transgenic/CD3 epsilon-mutant mice reveals a potential role for CD3 epsilon signals in T cell survival.

Amino Acid Sequence↗

PubMed2000

A mouse model of galactose-induced cataracts.

Galactokinase (GK; EC 2.7.1.6) is the first enzyme in the metabolism of galactose. In humans, GK deficiency results in congenital cataracts due to an accumulation of galactitol within the lens. In an attempt to make a galactosemic animal model, we cloned the mouse GK gene (Glk1) and disrupted it by gene targeting. As expected, galactose was very poorly metabolized in GK-deficient mice. In addition, both galactose and galactitol accumulated in tissues of GK-deficient mice. Surprisingly, the GK-deficient animals did not form cataracts even when fed a high galactose diet. However, the introduction of a human aldose reductase transgene into a GK-deficient background resulted in cataract formation within the first postnatal day. This mouse represents the first mouse model for congenital galactosemic cataract.

Aldehyde Reductase↗

PubMed2000

A HECT domain ubiquitin ligase closely related to the mammalian protein WWP1 is essential for Caenorhabditis elegans embryogenesis.

The highly conserved ubiquitin/proteasome pathway controls the degradation of many critical regulatory proteins. Proteins are posttranslationally conjugated to ubiquitin through a concerted set of reactions involving activating (E1), conjugating (E2), and ligase (E3) enzymes. Ubiquitination targets proteins for proteolysis via the proteasome and may regulate protein function independent of proteolysis. We describe the cloning and functional analysis of new members of the HECT domain family of E3 ubiquitin ligases. Murine Wwp1 encoded a broadly expressed protein containing a C2 domain, four WW domains, and a catalytic HECT domain. A Caenorhabditis elegans gene was cloned encoding a HECT domain protein (CeWWP1), which was highly homologous to murine and human WWP1. Disruption of CeWwp1 via RNA interference yielded an embryonic lethal phenotype, despite the presence of at least six additional C. elegans genes encoding HECT domain proteins. The embryonic lethality was characterized by grossly abnormal morphogenesis during late embryogenesis, despite normal proliferation early in embryogenesis. CeWWP1 must therefore have unique and nonredundant functions critical for embryogenesis.

Amino Acid Sequence↗

PubMed2000

Crystal structure of YbaK protein from Haemophilus influenzae (HI1434) at 1.8 A resolution: functional implications.

Structural genomics of proteins of unknown function most straightforwardly assists with assignment of biochemical activity when the new structure resembles that of proteins whose functions are known. When a new fold is revealed, the universe of known folds is enriched, and once the function is determined by other means, novel structure-function relationships are established. The previously unannotated protein HI1434 from H. influenzae provides a hybrid example of these two paradigms. It is a member of a microbial protein family, labeled in SwissProt as YbaK and ebsC. The crystal structure at 1.8 A resolution reported here reveals a fold that is only remotely related to the C-lectin fold, in particular to endostatin, and thus is not sufficiently similar to imply that YbaK proteins are saccharide binding proteins. However, a crevice that may accommodate a small ligand is evident. The putative binding site contains only one invariant residue, Lys46, which carries a functional group that could play a role in catalysis, indicating that YbaK is probably not an enzyme. Detailed sequence analysis, including a number of newly sequenced microbial organisms, highlights sequence homology to an insertion domain in prolyl-tRNA synthetases (proRS) from prokaryote, a domain whose function is unknown. A HI1434-based model of the insertion domain shows that it should also contain the putative binding site. Being part of a tRNA synthetases, the insertion domain is likely to be involved in oligonucleotide binding, with possible roles in recognition/discrimination or editing of prolyl-tRNA. By analogy, YbaK may also play a role in nucleotide or oligonucleotide binding, the nature of which is yet to be determined.

Amino Acid Sequence↗

PubMed2000

Ion-induced interfacial dynamics of phospholipid monolayers.

Ion-induced interfacial dynamics of phospholipid monolayers were studied by various electrochemical techniques. The lipid monolayers were constructed by using the mercapto derivatives of natural lipids that were self-assembled directly onto gold electrode surfaces in a tails-down fashion. The supported lipid assemblies appeared to act as rather effective electron-tunneling barriers with K3Fe(CN)6 as the redox probe, despite a relatively low surface coverage and/or a disordered surface structure. Upon the stimulation by alkaline-earth ions, the lipid layers appeared to undergo surface reorganization, exposing part of the electrode surface which resulted in the formation of microscopic mass-transfer lipid channels. The dimensions and/or the number of these channels increased with increasing ion concentrations, and this ion-gate effect appeared to be quite selective, with the most pronounced effects observed among the series of alkaline-earth ions with Ca2+.

Electrochemistry↗

PubMed2000

Solution structure of the MEF2A-DNA complex: structural basis for the modulation of DNA bending and specificity by MADS-box transcription factors.

The solution structure of the 33 kDa complex between the dimeric DNA-binding core domain of the transcription factor MEF2A (residues 1-85) and a 20mer DNA oligonucleotide comprising the consensus sequence CTA(A/T)(4)TAG has been solved by NMR. The protein comprises two domains: a MADS-box (residues 1-58) and a MEF2S domain (residues 59-73). Recognition and specificity are achieved by interactions between the MADS-box and both the major and minor grooves of the DNA. A number of critical differences in protein-DNA contacts observed in the MEF2A-DNA complex and the DNA complexes of the related MADS-box transcription factors SRF and MCM1 provide a molecular explanation for modulation of sequence specificity and extent of DNA bending ( approximately 15 versus approximately 70 degrees ). The structure of the MEF2S domain is entirely different from that of the equivalent SAM domain in SRF and MCM1, accounting for the absence of cross-reactivity with other proteins that interact with these transcription factors.

Amino Acid Sequence↗

PubMed2000

Purification of the newly found selenium-containing proteins in the arterial wall and brain of the rat.

Previously several selenium-containing proteins with different subunit molecular masses (M(r)) were detected in the arterial wall and brain of rats. In continuation of this work, after labeling of rats in vivo with [(75)Se]selenite, the new selenium-containing proteins of interest were purified on a Sephadex G-200 column followed by preparative isoelectric focusing. Nuclear analytical methods (gamma-counter and gamma-detector) were applied in the detection and identification of the (75)Se-labeled proteins. The two (75)Se-containing proteins from the arterial wall migrated as 15.0- and 67.0-kDa species on SDS-PAGE gels with pI values of 4.5 and 5.1, respectively. The three (75)Se-containing proteins from brain purified to homogeneity had M(r) values of 18.0, 30.0, and 42.9 kDa and pI values of 6.3, 6.5, and 6.0, respectively. Of these proteins, the 67.0-, 42.9-, and 30.0-kDa species may be yet not characterized selenoproteins with important biological functions.

Animals↗

PubMed2000

Extension of transverse relaxation-optimized spectroscopy techniques to allosteric proteins: CO- and paramagnetic fluoromet-hemoglobin [beta (15N-valine)].

We present the first steps in applying transverse relaxation-optimized spectroscopy (TROSY) techniques to the study of allosterism. Each beta-chain of the hemoglobin (Hb) tetramer has 17 valine residues. We have (15)N-labeled the beta-chain Val residues and detected 16 of the 17 (1)H-(15)N correlation peaks for beta-chain Val of the R state CO-Hb structure by using the TROSY technique. Sequence-specific assignments are suggested, based mainly on analysis of the (1)H pseudocontact-shift increments produced by oxidizing the diamagnetic R state HbCO to the paramagnetic R state fluoromet form. When possible, we support these assignments with sequential nuclear Overhauser effect (NOE) information obtained from a two-dimensional [(1)H,(1)H]-NOESY-TROSY experiment (NOESY, NOE spectroscopy). We have induced further the R-T conformational change by adding the allosteric effector, inositol hexaphosphate, to the fluoromet-Hb sample. This change induces substantial increments in the (1)H and (15)N chemical shifts, and we discuss the implication of these findings in the context of the tentative sequence assignments. These preliminary results suggest that amide nitrogen and amide proton chemical shifts in a selectively labeled sample are site-specific probes for monitoring the allosteric response of the ensemble-averaged solution structure of Hb. More important, the chemical-shift dispersion obtained is adequate to permit a complete assignment of the backbone (15)N/(13)C resonances upon nonselective labeling.

Allosteric Site↗