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Biomedical subjects

F Tian

Publications and source records attributed to F Tian.

At least 55 records · Page 3Linked to original sources
PubMed1999

Isolation of cDNAs encoding gibbon and monkey platelet and T cell activation antigen 1 (PTA1).

Human platelet and T cell activation antigen 1 (PTA1) is a 67kDa type I transmembrane glycoprotein mainly expressed on the surface of activated T cells and platelets, and is involved in the development of human cytotoxic T cell (CTL) as well as platelet activation and aggregation. We have cloned and sequenced gibbon PTA1 (gPTA1) and monkey PTA1 (mPTA1) cDNAs by RT-PCR from gibbon leukemic cell line MLA 144 and PHA-induced Rhesus monkey PBMC respectively. The mature proteins of gPTA1, mPTA1 and human PTA1 (hPTA1) share 93-95% amino acid similarity with the highest similarity in domain 1 of extracellular region. All the important features of PTA1 molecule are conserved among these Primates: (1) the ORF encoding 336 amino acid residues including signal sequence (18aa), extracellular region (232aa), transmembrane sequence (25aa) and cytoplasmic region (61aa); (2) two conserved pairs of Cys (Cys19 to Cys90 and Cys134 to Cys204) forming disulfide bonds stabilizing the two immunoglobulin superfamily V-like domains; (3) eight putative N-linked glycosylation sites (except gPTA1 with nine sites) and three O-linked glycosylation sites in extracellular region; and (4) predicated protein kinase C phosphorylation sites (Thr275 and Ser311), casein kinase II sites (Ser295 and The299) and the potential tyrosine phosphorylation site (Tyr304). These data indicate that PTA1 molecule is highly conserved among the Primates and may play important roles in immune response.

Amino Acid Sequence↗
PubMed1999

Correlations of structure, dynamics and function in the gramicidin channel by solid-state NMR spectroscopy.

The high resolution structure of the gramicidin A channel has been determined in a lamellar phase environment using solid-state NMR spectroscopy. While the fold is similar to previous characterizations, channel function is exquisitely dependent on structural detail. There is essentially no structural change upon cation binding and no significant change in dynamics. The cations appear to be adequately solvated in their binding site by no more than two carbonyls and no fewer than three water molecules at any one time. The relatively large number of water molecules allows for geometric flexibility and little selectivity among monovalent cations. However, the dehydration energies of cations clearly explain the selectivity for monovalent versus divalent cations. Moreover, the binding site is shown to be delocalized, resulting in a shallow potential energy well so that efficient cation conductance can be realized. The potential energy barrier at the bilayer centre has been shown to be rate limiting under certain circumstances through a correlation between conductance and the electrostatic interactions between cations at the gramicidin monomer-monomer junction and the indole dipole moments at the lipid-water interface. The dynamics are functionally important. The time-scale for carbonyl fluctuations about the C alpha-C alpha axis and kinetic rates for cation movement in the channel are the same, suggesting a correlation between molecular dynamics and kinetics. These functional correlations will be described in light of the recent K+ channel structure and the biological challenge to achieve both selectivity and efficiency.

Amino Acid Sequence↗
PubMed1999

[Gene therapy of AIDS].

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗
PubMed1999

[Traumatic perilymphatic fistula of round and oval windows (four cases reported)].

OBJECTIVE: To explore the diagnosis and treatment to traumatic perilymph fistula (PLF) of round and oval window. METHOD: Traumatic PLF was diagnosed by the traumatic history of head, neck and ear, the examinations of auditory and vestibular function, and the exploratory tympanotomy. The PLF of round and oval windows were repaired by fascia graft or tragus perichondrium and gelform. Four cases with traumatic PLF of round and oval window were reported in this paper, which included 2 cases hitten by hand, 1 by brick, 1 insulted by middle ear surgery. Exploratory tympanotomy was performed from one and half to nine months after injury. One case was misdiagnosed as Meniere's disease before confirming PLF. Exploration and repair of PLF underwent in all cases. RESULT: The symptom of vertigo relieved in all cases after surgery, while the hearing recovery was not evident. CONCLUSION: 1. Traumatic PLF is unrare, hence, traumatic PLF should be alerted if patients suffer from vertigo and hearing impairment after head and ear injury. 2. The features with vertigo attacks, fluctuating hearing loss and tinnutis should be distinguished from Meniere's disease. 3. Early exploratory tympanotomy and repair of PLF are effective for relieving vertigo and improving hearing.

Adult↗
PubMed1998

Cation binding induced changes in 15N CSA in a membrane-bound polypeptide.

Cation binding to the monovalent cation selective channel, gramicidin A, is shown to induce changes in the dipolar and chemical shift observables from uniformly aligned samples. While these changes could be the result of structural or dynamic changes, they are shown to be primarily induced by through-bond polarizability effects when cations are solvated by the carbonyl oxygens of the peptide backbone. Upon cation binding partial charges are changed throughout the peptide plane, inducing large changes in the 13C1 chemical shifts, smaller changes in the 15N chemical shifts, and even smaller effects for the 15N-13C1 and 15N-2H dipolar interactions. These conclusions are substantiated by characterizing the 15N chemical shift tensors in the presence and absence of cations in fast-frozen lipid bilayer preparations of gramicidin A.

Anti-Bacterial Agents↗
PubMed1998

[NiTi shape-memory alloy cramp used in repair of skull defect].

Fixation of silicon-polyester fiber network on skull defect was usually difficult to handle and the fixation was unstable. In order to solve these problems, NiTi shape-memory alloy cramp was adopted and 101 patients with skull defects were selected for this clinical trial. Among them, there were 79 males and 22 females, and the age ranged from 12-55 years old. The area of skull defect ranged from 3 cm x 4 cm to 10 cm x 16 cm. All of these patients received repairing of the skull defects by silicon-polyester fiber network which was fixed by NiTi memory alloy cramps. After operation, there was no complication. One hundred patients were followed up for 1-8 years, in which 97 cases returned to their normal work, and only 2 cases had a transient dysfunction of frontal muscle for 2 months. In addition, There were no loosening of the cramps, displacement of plastic network and malignant degeneration. The NiTi shape-memory alloy cramps had the following advantages: 1. Simple operative procedure; 2. Rigid fixation; 3. Mild postoperative tissue reaction; 4. Few postoperative complication; 5. Favorable effect of skull repair; 6. No interference with CT and MRI image; 7. No carcinogenicity.

Adolescent↗
PubMed1998

[Effect of dietary intake on body mass index in middle aged and elderly population].

The paper investigated and analyzed the relationship between the nutrient intake and body mass index (BMI) of 200 middle-aged and elderly people(aged 35 - 74 years) in Changsha. The result showed that the constituent rate of underweight (BMI< 18.5) was 6.5% and that of over-weight (BMI<25.0) was 23.5%. The amount of fat intake constituted slightly higher proportion in energy intake. The stepwise regression analysis indicates that the body mass index increases with the increasing intake of carbohydrates.

Adult↗
PubMed1998

[Determination of the soluble non-starch polysaccharides in rice and wheat bran by gas chromatography].

Cereal polysaccharides can be broadly classified into two distinct and chemically well-defined types. They are the storage polysaccharides (alpha-glucan) and the structural polysaccharides starch (beta-glucan) which are usually called non-starch polysaccharides (NSP). The determination of soluble non-starch polysaccharides in rice and wheat bran by gas chromatography has been developed. The free sugars in the sample were extracted with 80% ethanol. The residue was hydrolyzed in an acetic acid buffer solution (pH 5.0) in the presence of amylase and amyloglucosidase to remove starch. The soluble NSP obtained was further hydrolyzed in the acidic condition to produce the corresponding monosaccharides which were derivatized to form alditol acetates for GC analysis with allose as the internal standard. The GC conditions were OV-1701 column (25 m x 0.3 mm) with temperature program from 195 degrees C to 225 degrees C and FID.

Chromatography, Gas↗
PubMed1998

[Nontypical limited resection of the lung].

OBJECTIVE: To evaluate the role of limited resection in the treatment of lung disease. METHOD: From 1989 to 1996, 46 limited resections were performed on 35 patients with lung diseases. All patients were followed up for 0.5 to 7 years (mean 29.3 months). RESULT: There were no operative deaths and operative complications. In 16 patients with benign lung diseases, no recurrences and late complications were found. In 5 patients with primary lung cancers, 2 died 1.5 and 2 years after operation, respectively, and 3 are still living well for 2.5, 4 and 5 years postoperatively. In 14 patients with metastatic lung diseases (10 with bilateral multiple metastases), 216 metastatic lesions were excised. 1-, 3-, and 5-year survival rates were 78.5%, 50% and 21.4% respectively. CONCLUSION: Limited lung resection could be an additional option and a surgical alternative to conventional lung resection for some compromised patients.

Adolescent↗
PubMed1997

[Hepaticocholangiochole cystostomy plus construction of subcutaneous tunnel of the gallbladder in the treatment of hepatolithiasis with bile duct stricture].

A novel operation was designed by using Hartmann's pouch of the gallbladder to anastomose stone-strictured intrahepatic bile duct while leaving the common bile duct and Oddis sphincter intact and fixing the fundus of the bladder subcutaneously. 28 patients with intrahepatic bile duct stones and strictures underwent the operation successfully, and recovered well. There were no postoperative complications such as reflux cholangitis or disturbances of GI tract.

Adolescent↗
PubMed1996

Monovalent cation transport: lack of structural deformation upon cation binding.

Cations often deform the structure of regulatory proteins to affect a functional response, but for other protein functions a more passive effect is desired. For instance, it is shown here that in the conductance of Na+ by the gramicidin channel there appears to be no significant structural deformation of either the side chains or backbone upon Na+ binding in the channel. This is based on 15N and 13C chemical shifts, 2H quadrupolar interactions, and 15N-2H dipolar interactions obtained by solid-state NMR spectroscopy of uniformly aligned lipid bilayer preparations of the gramicidin channel in the presence and absence of Na+. This conclusion is despite some significant changes in the 15N alpha and 13C1 chemical shift values which are argued here to be the result of indirect polarization effects upon cation binding rather than reflections of structural and dynamic changes. The lack of structural deformation implies that Na+ moves to the carbonyl oxygens lining the pore of this channel for solvation rather than the carbonyl groups moving in toward the channel axis. This forces the cations onto a helical path following the positions of the carbonyl oxygens around the channel pore. Furthermore, an ideal binding site geometry for Na+ in the channel is avoided. Instead, adequate binding energy is provided by the channel to compensate for the loss of hydration energy when the cations enter the channel. The avoidance of strong binding ensures that efficient transport of the cations through the channel can be realized.

Amino Acid Sequence↗
PubMed1996

Conformational trapping in a membrane environment: a regulatory mechanism for protein activity?

Functional regulation of proteins is central to living organisms. Here it is shown that a nonfunctional conformational state of a polypeptide can be kinetically trapped in a lipid bilayer environment. This state is a metastable structure that is stable for weeks just above the phase transition temperature of the lipid. When the samples are incubated for several days at 68 degrees C, 50% of the trapped conformation converts to the minimum-energy functional state. This result suggests the possibility that another mechanism for functional regulation of protein activity may be available for membrane proteins: that cells may insert proteins into membranes in inactive states pending the biological demand for protein function.

Magnetic Resonance Spectroscopy↗
PubMed1996

Natural killer cell cytotoxicity assay with time-resolved fluorimetry.

A new time-resolved fluorimetric method for the measurement of natural killer (NK) cell cytotoxicity has been developed by labelling the target cell K562 with a new synthesized fluorescence marker KLUK. The method has advantages of higher sensitivity, time-saving, good reproducibility and has no radioactivity problems. A satisfactory result is obtained by comparing it with 51Cr release method. It demonstrates that the new marker provides an alternative to currently used radioactive markers for the assessment of in vitro cellular cytotoxicity.

Adult↗