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Biomedical subjects

Z S Lin

Publications and source records attributed to Z S Lin.

At least 19 recordsLinked to original sources
PubMed2001

Patchy environment as a factor of complex plankton dynamics.

We study the role of the diffusive interaction in plankton dynamics in a patchy environment. We use a minimal reaction-diffusion model of the nutrient-plankton-fish food chain to simulate the diffusive interaction between fish-populated and fish-free habitats. We show that such interaction can give rise to spatiotemporal plankton patterns. The plankton dynamics depend on the fish predation rate and can exhibit both regular and chaotic behavior. We show that limit cycle and chaotic attractor coexist in the system. The entire basin of attraction of the limit cycles is found to be riddled with "holes" leading to the competitive chaotic attractors. The chaotic dynamics is typical of a wide range of the fish predation rates.

Animals↗
PubMed2000

[Molecular cytogenetic characterization of a new wheat line YW443 with resistance to barley yellow dwarf virus].

A new wheat line YW443 with BYDV resistance and good traits was developed from the combination of PP9-1/Shan7859¿Fengkang 8. The wheat line YW443 was identified by BYDV resistance analysis, genomic in situ hybridization (GISH), RFLP and RAPD analysis. The results indicated as follows: (1) YW443 was resistant to GPV and GAV strains of BYDV; (2) YW443 is a homozygous wheat-Thinopyrum intermedium translocation line with a pair of BYDV resistance genes; (3) The 7StL segment of Th. intermedium carring BYDV resistance gene was transferred onto the distal end of the wheat chromosome 7D long arm, the line YW443 was 7DS.7DL-7StL translocation; (4) A RAPD marker OPR19(-900) could detect the DNA of Th. intermedium 7StL in L1 and L1 derivatives including translocation lines YW443, YW642 etc. The markers may be used as a selecting marker for the BYDV resistance breeding program.

In Situ Hybridization↗
PubMed2000

[Identification of the barley chromosome in wheat by GISH and RFLP].

The barley chromosome in wheat was identified by genomic in situ hybridization (GISH) in which biotin labelled total genomic DNA of barley Betzes was used as probe and the unlabelled total DNA of common wheat Chinese Spring (CS) as blocking DNA. A series of wheat materials were tested as follows: two disomic alien substitution and monosomic alien addition lines, 2n = 43; two monosomic alien substitution lines, 2n = 42; seven disomic alien substitution lines, 2n = 42. RFLP probe psr131 on the short arm of the homologous group 2 was used to analyze the barley chromosome in wheat. The result indicated that there was a same band in barley Betzes and substitution line A5. The chromosome 2A of A5 was substituted by the chromosome 2H of barley. These materials will be useful in transferring the valuable genes in the chromosome 2H to wheat.

Chromosomes↗
PubMed2000

[Surgical treatment for the recurrent patients after palatopharyngoplasty].

OBJECTIVE: To study the surgical treatment for the recurrent patients after palatopharyngoplasty (PPP). METHOD: Five patients which were confirmed recurrence by sleep survey and examinations were reported. RESULT: The pharyngeal cavity was narrower obviously ten months after ppp than before ppp. The anteroposterior and transverse distances were (4.06 +/- 2.94) mm and (11.40 +/- 4.16) mm respectively. After dilatation, the distances were (11.90 +/- 3.25) mm and (21.00 +/- 4.18) mm separately, and were increased significantly than before (P < 0.01). Two patients were cured and three cases marked, and all patients were not recurrent post-operation with no complications. CONCLUSION: The recurrence was mainly concerned with the unsuitable manipulation in PPP. Selecting the cooperation and proper surgical treatment, the better effect was also obtained for the recurrent patients.

Cicatrix↗
PubMed1998

A novel approach to distinguish between intron-containing and intronless genes based on the format of Z curves.

A novel method to distinguish between intron-containing and intronless DNA sequences has been proposed, based on different statistic behaviors between them. In this method, DNA sequences are first represented as Z curves. Three exponents alpha, beta and gamma for each given sequence are calculated based on the format of the Z curve for the DNA sequence. A three-dimensional space is spanned by the three exponents. Each DNA sequence may be represented by a point in this space. One hundred intronless and intron-containing genes, respectively, were selected randomly from the GenBank or EMBL database. It is shown that the 200 points are roughly distributed in different regions. The best separating plane to separate the two regions is obtained by using Fisher's discriminant algorithm. For any given sequence to be discriminated, calculate three exponents alpha, beta and gamma, corresponding to a point in the three-dimensional space. If the point is situated at the upper region of the separating plane, the sequence is discriminated as an intronless one; otherwise, the sequence is an intron-containing one. A test of the method for the sequences in an independent test set shows that the discriminant accuracy reaches as high as 89.0%.

Animals↗
PubMed1998

A new fourier transform approach for protein coding measure based on the format of the Z curve.

MOTIVATION: At the core of most protein gene-finding algorithms are the coding measures used to make a decision on coding/non-coding. Of the protein coding measures, the Fourier measure is one of the most important. However, due to the limited length of the windows usually used, the accuracy of the measure is not satisfactory. This paper is devoted to improving the accuracy by lengthening the sequence to amplify the periodicity of 3 in the coding regions. RESULTS: A new algorithm is presented called the lengthen-shuffle Fourier transform algorithm. For the same window length, the percentage accuracy of the new algorithm is 6-7% higher than that of the ordinary Fourier transform algorithm. The resulting percentage accuracy (average of specificity and sensitivity) of the new measure is 84.9% for the window length 162 bp. AVAILABILITY: The program is available on request fromC.-T. Zhang. CONTACT: ctzhang@tju.edu.cn

Algorithms↗
PubMed1998

Prediction of the helix/strand content of globular proteins based on their primary sequences.

An improved multiple linear regression method has been proposed to predict the content of alpha-helix and beta-strand of a globular protein based on its primary sequence. The amino acid composition and the auto-correlation functions based on the hydrophobicity profile of the primary sequence have been taken into account in the algorithm. The resubstitution test shows that the average absolute errors are 0.077 and 0.073 with the standard deviations 0.059 and 0.057 for the prediction of the content of alpha-helix and beta-strand, respectively. A stringent cross-validation test, i.e., the jackknife test, shows that the average absolute errors are 0.087 and 0.081 with the standard deviations 0.067 and 0.065 for the prediction of the content of alpha-helix and beta-strand, respectively. Both tests indicate the self-consistency and the extrapolating effectiveness of the new algorithm. This greatly improves on previous results (Eisenhaber,F., Imperiale,F., Argos,P. and Frommel,C., 1996, Proteins, 25, 157-168). Compared with other methods currently available, our method has the merits of simplicity and ease-of-use as well as a higher prediction accuracy. The only input of the method is the primary sequence of the query protein to be predicted. The program is available on request via e-mail: ctzhang@tju.edu.cn.

Amino Acid Sequence↗
PubMed1996

Dopaminergic control of light-adaptive synaptic plasticity and role in goldfish visual behavior.

Dopamine has been implicated in processes of retinal light and dark adaptation. In goldfish retina, horizontal cell dendrites elaborate neurite processes (spinules) into cone terminals, in a light- and dopamine-dependent manner. However, the functions of retinal dopamine and the horizontal cell spinules in visual behavior are unknown. These issues were addressed in behavioral, electroretinographic, and anatomical studies of normal fish and those with unilateral depletion of retinal dopamine induced by intraocular (i.o.) injections with 6-hydroxydopamine (6-OHDA). Dopamine interplexiform cells (DA-IPC) disappear within 2 weeks after 6-OHDA injection; cell bodies appear at the marginal zone within 6 weeks at which time neurites slowly reinnervate the retina with a sparse plexus over the next 12 months. We found that dopamine depletion increased light sensitivity at photopic but not scotopic backgrounds by 2.5 log units, an effect mimicked by i.o. injections of dopamine D1 and D2 antagonists. The ERG b-wave increment thresholds were the same for control and dopamine depleted eyes, indicating a normal transition from rod to cone systems in the ON pathway. Light-dependent spinule formation was reduced by about 60% in dopamine-depleted retinas, but returned to normal by 3 months and 9 months after injection in the entire retina, even areas not directly innervated with DA-IPC processes. Spinule formation in vivo was inhibited 50% with i.o. injection of SCH 23390 in control retinas as well as throughout 3 month 6-OHDA injected retinas, including DA-IPC free areas. This latter result indicates a volume effect of dopamine, diffusing laterally through the retina over several millimeters, in regulating spinules. We conclude that DA-IPCs regulate sensitivity to background at photopic levels not via the ON pathway, but perhaps the OFF pathway. Goldfish display both increased sensitivity to light and a normal Purkinje shift in the ERG b-wave whether or not horizontal cell spinules are present, indicating that dopamine control of photopic vision in fish is not mediated through light-induced spinule formation of horizontal cell dendrites.

Adaptation, Ocular↗
PubMed1996

Outcome of severe brain injury: a multimodality neurophysiologic study.

We screened all head-injured trauma patients admitted to Lehigh Valley Hospital during a 2-year period. From 725 screened patients, 69 patients in a coma on the second day after trauma were entered into this study. During the first week, these patients underwent electroencephalography (EEG), evoked potentials, ocular pneumoplethysmography, and transcranial Doppler (TCD) sonography. Clinical examinations were undertaken 2 and 7 days after trauma. Test results were correlated with functional clinical outcome at 6 months. In a multiple regression analysis, EEG was the major independent variable that significantly predicted 6-month outcome based on Glasgow Outcome Scale score. Transcranial Doppler sonography contributed a small additional component. Though EEG was the most significant predictive factor in this neurophysiological battery, it did not add significantly to the predictive power of Glasgow Coma Scale score determined at day 7. These findings suggest that in neurophysiologic testing in this type of patient is not useful in improving predictive outcome data.

Adolescent↗
PubMed1995

Differential effects of dopamine depletion on the distribution of [3H]SCH 23390 and [3H]spiperone binding sites in the goldfish retina.

The distributions of dopamine D1 and D2 receptors were studied in intact goldfish retina with in vitro autoradiography. Specific [3H]SCH 23390 binding (D1 receptors) was greatest over the outer plexiform layer (OPL)/horizontal cell bodies and less so over the inner nuclear and inner plexiform layers (IPL). Specific [3H]spiperone binding (D2 receptors) appeared in two bands, over the OPL/horizontal cell bodies and the IPL. Depletion of retinal dopamine, by intraocular injections of 6-hydroxydopamine, had no effect on the pattern and density of [3H]SCH 23390 binding; however, specific [3H]spiperone binding over the OPL and IPL was virtually eliminated, suggestive of D2 autoreceptors on dopamine interplexiform cells. These data are consistent with electrophysiological studies indicating the presence of D1 and D2 receptors in both plexiform layers of the goldfish retina.

Adrenergic Agents↗
PubMed1994

Heterogeneity of GABAA receptor in goldfish retina.

The possibility of GABAA receptor heterogeneity in goldfish retina was studied with immunocytochemical and biochemical approaches: 1) immunoblotted membrane particulates of goldfish retina with mAb 62-3G1; 2) immunoprecipitation of the detergent-solubilized membrane proteins with mAb 62-3G1 followed by the receptor binding assay; 3) photoaffinity labeling of the membrane particulates with 3H-flunitrazepam (FNZ) and visualization of the labeled receptors by SDS-PAGE and fluorography; 4) dry autoradiography of 3H-muscimol and 3H-FNZ binding sites on frozen sections. Immunoblots showed that 62-3G1 reacted with 55-57.5 kDa M(r) polypeptides, similar to the muscimol-binding subunit of the receptor complex in bovine brain; while 3H-FNZ photoaffinity labeled the 52.5 kDa and 41-43 kDa M(r) polypeptides. Immunoprecipitated receptors bound only 3H-muscimol, not 3H-FNZ. An attempt to precipitate the 3H-FNZ photolabeled polypeptides failed. Dry autoradiography showed 3H-FNZ binding only in the inner plexiform layer (IPL); the binding was enhanced with gamma-aminobutyric acid (GABA) and blocked by clonazepam. In contrast, 3H-muscimol was bound in both the outer plexiform layer (OPL) and IPL, similar to that observed with 62-3G1 immunocytochemistry. We suggest that there are two subtypes of GABAA receptor in the goldfish retina: 1) GABAA receptors that are not linked to a benzodiazepine (BZD) receptor are located in the OPL and at amacrine-to-amacrine and amacrine-to-ganglion cell synapses in the IPL and are recognized by 62-3G1; 2) GABAA receptors that are linked to a BZD receptor are located only in the IPL, largely at amacrine-to-bipolar cell synapses and are not recognized by mAb 62-3G1.

Affinity Labels↗
PubMed1994

Primary angiitis of the central nervous system: unusual MR appearance.

The MR findings of a biopsy-proved case of primary angiitis of the central nervous system are described and compared with previously reported cases. Multiple punctate and linear areas of gadopentetate dimeglumine enhancement were present in the brain stem and white matter and appear to correspond to the inflammatory reaction of the small perforating vessels and perivascular tissues seen in the pathologic specimen.

Arteries↗
PubMed1992

Localization of GABAA receptor subtypes in the tiger salamander retina.

Dry autoradiography was used to determine the distribution of GABAA binding sites in tiger salamander retina. High-affinity binding of [3H]-flunitrazepam [( 3H]-FNZ) was used to localize benzodiazepine receptors (BZR) and [3H]-muscimol was used to localize the GABAA recognition site. Specific [3H]-FNZ binding was present only in the inner retina, primarily in the inner plexiform layer (IPL). Co-incubation with GABA enhanced [3H]-FNZ binding by 20-50%. [3H]-muscimol binding was found throughout the IPL and in the outer plexiform layer (OPL). Mouse monoclonal antibodies 62-3G1 and BD-17, that recognize the GABAA beta 2, beta 3 polypeptides, and BD-24, that recognizes the GABAA alpha 1 polypeptide, did not label either the OPL or IPL, despite numerous variations in the fixation and immunoprocessing methods. GABAA receptor location, as revealed by [3H]-muscimol binding, matches the distribution of presumed GABAergic terminals in the OPL and IPL. We suggest that there are at least two subtypes of GABAA receptor in the tiger salamander retina: one type is present only in the inner retina, primarily in the IPL and is functionally coupled to BZRs; the other type is located in the OPL and is not coupled to the BZRs. Furthermore, GABAA receptors in the tiger salamander retina appear to be of a different epitope than GABAA receptors in numerous other preparations that are recognized by mAbs 62-3G1, BD-17, and BD-24.

Ambystoma↗
PubMed1989

Retinoids bound to interstitial retinol-binding protein during light and dark-adaptation.

High-performance liquid chromatography was used to determine the types and amounts of retinoids bound to interstitial retinol-binding protein (IRBP) during light- and dark-adaptation in frogs. IRBP was separated from CRBP and CRA1BP by ion-exchange chromatography and quantitated by determining the amount of Serva Blue R dye bound to it in stained sodium dodecyl sulfate polyacrylamide gels. The amount of IRBP was not significantly different in light- and dark-adapted eyes (0.15 +/- 0.05 nmol/eye compared with 0.18 +/- 0.08 nmol/eye). In the dark-adapted state, IRBP bound mainly 11-cis retinol and 11-cis retinal in quantities that summed to about 1 mol/mol IRBP. After the onset of light-adaptation, all-trans retinol increased from its very low dark-adapted level, peaked at 0.2 mol/mol IRBP and then declined to the dark-adapted level again. Concomitantly, the total retinoid bound to IRBP fell, mainly because there was a drop in the amount of 11-cis retinal. During dark-adaptation, the amount of 11-cis retinal increased. No significant changes were seen in the amount of 11-cis retinol in light and darkness. These findings support the hypothesis that when rhodopsin is bleached IRBP transports all-trans retinol from the retina to the pigment epithelium and that it delivers 11-cis retinal to the rod outer segments for rhodopsin regeneration.

Animals↗
PubMed1978

Characteristics of calcification in tumors of the pineal gland.

Thirty-two cases of proved pineal tumor were analyzed. Calcification was seen in 75%. The size, character, and position of the calcification were useful indicators of abnormality on plain-film evaluation. Fray's cranioangle method was more sensitive than Oon's method in determining abnormal position of the calcified pineal tumor on the lateral skull film. Most calcifications were displaced postero-inferiorly or inferiorly, which can be explained by obstructive hydrocephalus or direct tumor expansion.

Adolescent↗