Search PubMed⌕ Search

Biomedical subjects

Y Zhao

Publications and source records attributed to Y Zhao.

At least 919 records · Page 51Linked to original sources
PubMed1995

[Application of transcranial color Doppler flow imaging in the carotid cavernous sinus fistulae].

Transcranial color Doppler flow imaging (TCCDFI) allows for simultaneous two-dimensional structural imaging and Doppler evaluation of blood flow through intact skull. With this technique, we evaluated 10 patients with carotid cavernous sinus fistulae (CCSF) and 35 normal volunteers. Each of them was confirmed by angiography. TCCDFI showed that patients with CCSF had typical signs in the affected part. The cavernous sinus had mosaic color shade. Pulse-Doppler showed disorderly polydirection vortex blood flow spectra in the mosaic color shade associated with murmur. Two-dimensional sonography and color Doppler imaging demonstrated a dilated superior ophthalmic vein (SOV) with arterialized blood flow. The Vmax of MCA and ACA in the affected side were lower than the healthy and normal side. The RI was lower than that of the healthy side and PCA of both sides was lower than that in normal volunteers. Two patients were examined after tubolization. Mosaic color shade disappeared and SOV returned to normal venous flow in patients completely occluded. Mosaic color shade reduced and SOV still aterialized blood flow in partly occluded patients. This technique helps to confirm the clinical diagnosis and to track the hemodynamics of CCSF patients and evaluate the effect of therapy.

Adolescent↗
PubMed1995

Nutritional regulation of the protein kinases responsible for the phosphorylation of the alpha-ketoacid dehydrogenase complexes.

The branched-chain alpha-ketoacid dehydrogenase (BCKDH) and pyruvate dehydrogenase (PDH) complexes are regulated by phosphorylation cycles catalyzed by complex-specific protein kinases and phosphoprotein phosphatases. Molecular cloning of these mitochondrial protein kinases has established a new family of protein kinases in eukaryotes that appears related by primary sequence to the histidine protein kinase family of prokaryotes. Changes in the activities of both kinases that are stable, i.e., not caused directly by allosteric effectors, correlate inversely with the changes in the activity states of the complexes that occur in different nutritional states. For example, BCKDH kinase activity is increased and the BCKDH complex activity state is decreased in rats fed diets deficient in protein. The increase in BCKDH kinase activity is due to an increase in the amount of BCKDH kinase protein bound to the BCKDH complex. The message level for BCKDH kinase also increases in the liver of rats starved for protein, suggesting a pretranslational mechanism exists for the long-term regulation of BCKDH kinase. Starvation and high-fat feeding cause a stable increase in PDH kinase activity and a corresponding decrease in activity state of the PDH complex. The mechanism responsible has not been defined.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗
PubMed1995

A novel electron paramagnetic resonance spin label and its application to study the cross-bridge cycle.

We have used a novel alpha-iodoketone spin-label (IKSL) to study myosin head orientation and cross-bridge dynamics in the putative pre-powerstroke state. Possible perturbation of the cross-bridge cycle by the label was assayed by the sinusoidal analysis method (Kawai and Brandt, 1980; Kawai and Zhao, 1993), which determines the rate constants of the elementary steps in the cycle. A comparison of the rates obtained from unlabeled and IKSL fibers revealed small (10-20%) changes in the ATP hydrolysis rate and in the rate constants of the elementary steps. The labeling induced small changes (< 13%) in the distribution of the cross-bridges among the various intermediate states. Pre-powerstroke cross-bridges were induced by aluminum fluoride in the presence of Ca2+ and ATP. In this state, force development is inhibited, but a large proportion (40%) of the cross-bridges are still attached to the thin filament. We have used conventional electron paramagnetic resonance to measure orientation, and have found that the pre-powerstroke heads are as disordered as in relaxation. Their mobility, as determined by saturation transfer electron paramagnetic resonance, was significantly restricted. Assuming that stiffness is proportional to the fraction of strongly attached heads, the rotational correlation time of the bound heads is estimated to be tau r = approximately 150-400 microseconds.

Aluminum Compounds↗
PubMed1995

[Identifying the existence of cultured human epidermal allografts with PCR techniques].

It is still controversial whether cultured human epidermal allografts can survive long or not because of the lack of convincing evidence to prove it. In this study, three PCR techniques for the individual identification were used to test the existence of cultured allogeneic keratinocytes when it has been transplanted to differents kinds of wounds. With these methods, the donor genetic marks were found in 27 biopsies of 16 patients who had cultured epidermal cells allografted. The longest biopsy time was 92 days after grafting. The results strongly indicated that the survival time of cultured epidermal allografts was prolonged. The advantage and disadvantage of using the PCR techniques were discussed and the fate of the cultured epidermal allografts could be determined if these techniques are used properly.

Adolescent↗
PubMed1995

Research of the exploitation of human resources in blind prevention and primary eye care.

PURPOSE: This research studied how to establish a relatively advanced blindness prevention and eye care cause in economically underdeveloped countryside. METHODS: Ophthalmic vocational schools and professional lectures were held to train "practical type" primary eye care workers for the countryside. Further study in high-level (above provincial) hospitals was taken to train blindness prevention & eye care backbones and leaders. RESULTS: In 1986, the ratio of the number of the eye care workers of all levels to the number of the whole population in the prefecture was 1:26,000. In 1992, it rose to 1:17,000. An eye care network of 222 stations had been established in the countryside. Ten in the 13 county hospitals had a seperated ophthalmology department, in which 3 were awarded "National advanced blindness prevention County". Twenty one hospitals were appointed as the Unit of Surgical Vision-Rehabilitation of Cataract. Blindness prevention and eye care covered 1,000,000 population (eye care available within 5 kilometers), 23.5% of the whole population. CONCLUSIONS: In a demographically large but economically underdeveloped countryside area, the key to wide-range blindness prevention and eye care is to exploit human resources effectively. We should train "Practical type" primary eye care workers, and have a number of department leaders who are authoritive, influential in this field and ready to sacrifice to this cause.

Blindness↗
PubMed1995

Interactions of the glutelin Gt3 5' flanking regulatory regions with rice nuclear proteins.

Three DNA binding activities, BP-1, BP-2 and BP-3, which interact with the 5' flanking region of the rice glutelin Gt3 gene, were identified by gel retardation assays of rice seed nuclear extracts. The DNA binding activities were seed-specific as identical DNA-protein complexes were not observed when nuclear extracts from leaf tissue or suspension culture cells were analyzed, suggesting that these DNA binding activities are involved in seed-specific expression of the Gt3 gene. The DNA sequences recognized by these DNA binding activities were identified by DNaseI foot-printing and Bal 31 nuclease mapping analyses. BP-1 recognizes DNA sequences located at -272 bp to -259 bp relative to the transcriptional start site. This DNA segment contains a sequence motif that is conserved among several seed protein genes, implicating that the motif may be a common cis-regulatory element determining seed-specific expression of these genes. BP-2 interacts with sequences located between -861 bp to -838 bp while BP-3 interacts with sequences upstream of -788 bp. The temporal levels of BP-2 binding activity parallel the steady state levels of the Gt3 mRNAs during seed development. Overall, these results and those obtained from in vivo promoter analysis in transgenic plants [Zhao et al. (1994) Plant Mol. Biol. 25: 429] indicate that multiple regulatory elements located at two spatially separated regions of the Gt3 promoter are involved in endosperm-specific and temporal regulation.

Base Sequence↗
PubMed1995

[Pharmacologic action profile of crataegus extract in comparison to epinephrine, amirinone, milrinone and digoxin in the isolated perfused guinea pig heart].

Using isolated perfused guinea pig hearts experiments were performed to investigate the influence of crataegus extract LI 132 (Faros 300, CRA) in comparison to other inotropic drugs--epinephrine (adrenaline, ADR), amrinone (AM), milrinone (MIL) and digoxin (DIG)--on different functional parameters, with special emphasis on the effective refractory period of the myocardium. The simultaneous registration of appropriate parameters allowed to relate the effect on the refractory period to the inotropic, chronotropic, dromotropic and coronary actions of these compounds at each concentration level. All substances--with the exception of CRA--shortened the effective refractory period concentration-dependently besides their known other functional effects (max.: 1 x 10(-5) mol/l ADR by 38%, 7 x 10(-7) mol/l DIG by 26%, 1 x 10(-4) mol/l MIL by 13% and 5 x 10(-4) mol/l AM by 1.6%). Related to the positive inotropy the shortening was most effective under MIL (1.32 ms/mN), followed by AM (0.65 ms/mN), DIG (0.40 ms/mN) and ADR (0.28 ms/mN). On the contrary, CRA produced a prolongation of the effective refractory period by maximally 10% resp. by 2.54 ms/mN. Thus, the pharmacologic profile of CRA differs from that of other inotropic compounds mainly in this parameter (with potentially reduced arrhythmogenic risk).

Amrinone↗
PubMed1995

[Chemical constituents of Clematis intricata Bunge].

Five compounds were isolated from the aerial part of Clematis intricata for the first time. On the basis of spectral data (UV, IR, MS, 1HNMR and 13CNMR), they were identified as scopoletin, caffeic acid, inositol, 1-tria-contanol and beta-sitosterol.

Caffeic Acids↗
PubMed1995

[Surveillance of levels of neutralizing antibodies against poliovirus among children aged 0-3 in rural areas of Anhui Province].

Levels of neutralizing antibodies against poliovirus (PV) in 1,755 children aged 0-3 sampled randomly from 18 counties in Anhui Province were determined in September, 1993. Results showed the positive rates and geometric mean titer (GMT) of neutralizing antibodies against PV type 1, 2 and 3 were 96.98%, 96.01% and 96.18%, and 524.80, 323.59 and 436.50, respectively. Immune level of children was considerable high in each county sampled. No significant difference was found among different age groups and between boys and girls in positive rates and GMT of polioantibodies, but there was significant difference in them between children administered varied doses of oral polio vaccine (OPV). Children investigated took four doses of OPV in average, and their GMT was in proportion to the dose they took. Positive rate of PV antibodies was more than 95% in children who finished the full course of OPV immunization. There were very few townships or villages with a low coverage of OPV immunization in children. It indicated polio immune status was in a higher level in the Province.

Antibodies, Viral↗
PubMed1995

[A quantitative study on nuclear DNA content and morphological parameters in ovarian cystadenocarcinoma].

OBJECTIVE: To study nuclear DNA content and morphological parameters in ovarian cystadenocarcinoma. METHODS: Nuclear DNA content and morphological parameters were quantitatively determined by image analysis technology in 56 cases of ovarian cystadenocarcinoma, 12 benign ovarian cystadenoma and 10 normal ovarian epithelial tissue. RESULTS: DNA content of ovarian cystadenocarcinoma was the highest among the three groups; and there were significant differences between the groups (P < 0.01). In the aspect of morphometry, nuclear circle was greatly different among the three groups (P < 0.01). There was no significant variances in nuclear parameter and area (P > 0.05). Nuclear DNA content of ovarian cystadenocarcinoma was related to its histopathological classification, histological grade and clinical stages (P < 0.01, P < 0.05). There was a reverse relationship between the DNA ploidy level and clinical prognosis. The 2-year survival rate of ovarian cystadenocarcinoma with diploidy/near diploidy pattern was higher than that with aneuploid pattern (P < 0.01). CONCLUSIONS: Nuclear DNA content of ovarian cystadenocarcinoma is a useful marker in reflecting the biological behavior and is of practical value in diagnosis, the choice of treatment methods and in the evaluation of results and prognosis.

Adolescent↗
PubMed1995

[Anti-hepatitis C virus screening to prevent hepatitis C virus infection in blood donors].

Before carrying out anti-hepatitis C virus (anti-HCV) screening in blood donors, 433 plasma donors and 461 whole blood donors from 4 county plasmapheresis units and 5 city blood centres in Hebei province were surveyed. Anti-HCV positive rates were 55.5% and 10.2% in the two populations respectively. The anti-HCV positive rates also differed between qualified and unqualified donors. In qualified and unqualified plasma donors, they were 46.2% and 91.6% respectively and in qualified and unqualified whole blood donors 5.8% and 42.3% respectively. One year after anti-HCV screening, 793 plasma donors and 873 whole blood donors in 3 city blood centres and 4 county hospitals were surveyed, the anti-HCV positive rates in plasma and whole blood donors were 4.0% and 0.2% respectively. Compared with those before screening, there were 91.3% and 96.6% reduction respectively. The anti-HCV positive rate in voluntary donors was 0.5%. All the 86 first time donors were negative for anti-HCV before and after screening.

Blood Donors↗
PubMed1995

[Confirmation of the persistence of cultured allogeneic keratinocytes by DNA fingerprints].

We have successfully used DNA fingerprint to confirm the existence of cultured allogeneic keratinocytes after transplantation. Four biopsies from two burn patients who had been grafted with cultured allogeneic keratinocytes were examined by this technique. The results showed that the cultured allogeneic keratinocytes could survive on the grafted wounds for at least 28 days post grafting.

Adult↗
PubMed1995

[Evaluation of the condylar position in the diagnosis of temporomandibular joint dysfunction syndrome].

26 cases with Temporomandibular Joint Dysfunction Syndrome (TMJDS) were included in the present study. Fully corrected lateral tomogrames of TMJ in the intercuspid position were taken for all the cases; and fully corrected lateral arthrotomogrames were taken for 19 cases (21 joints) of them. The area and linear measurements of the joint space were made with the aid of computer. The results showed that the position of the condyle in the patients with TMJDS was located in the posterior position of the fossa. Statistics results showed that there was significant difference between the patient group and control group. Although the posterior displacement of the condyle was often associated with the anterior displacement of the disc, it was not always agreement with the anterior disc displacement. So, the exact diagnosis of disc displacement should be still on the basis of arthrography or other examinations, such as CT or MRI.

Adolescent↗
PubMed1995

Identification of 2-[125I] iodomelatonin binding sites in the thymus of mice and its significance.

The melatonin binding sites in membrane preparations of the mouse thymus were demonstrated using 2-[125I] iodomelatonin as a radioligand. The binding sites were stable, saturable, reversible and of high affinity. Studies on specificity of 2-[125I] iodomelatonin binding suggested that the 2-[125I] iodomelatonin binding sites are highly specific for melatonin. These binding sites fulfilled the standard criteria for receptors. Our work suggested that melatonin should have direct regulatory action on immune system mediated through the melatonin binding sites. Studies on the circadian rhythm showed that there existed the circadian rhythm in the binding capacity for 2-[125I] iodomelatonin in the mouse thymus with the peak values at 12:00-16:00 and the trough values between 00:00 and 4:00. The subcellular distribution of 2-[125I] iodomelatonin binding sites in the mouse thymus was in the following descending order: nuclear > mitochondrial > microsomal > cytosolic fraction. There was also an age-related decrease in 2-[125I] iodomelatonin binding in the mouse thymus. This is correlated with the involution of the thymus.

Age Factors↗
PubMed1994

Molecular cloning of two small GTP-binding proteins from human skeletal muscle.

Two distinct cDNAs encoding small GTP-binding proteins were isolated from a human fetal skeletal muscle cDNA library. Nucleotide sequence analysis revealed that one clone encodes a protein of 218 amino acids, which shares highest amino acid identities (over 90%) with the members of YPT3 GTP-binding proteins subfamily and was termed H-YPT3; and the second clone encodes a protein of 201 amino acids, which exhibits strongest homology to rab1A, rab1B, and YPT1 at its N-terminus but diverges notably from these rab family members at the C-terminus. The second cDNA may represents a novel member of the small GTP-binding protein family and was designated H-ray. Northern blot analysis shows that both genes are ubiquitously expressed. Using a bacterial expression vector, each clone was overexpressed in Escherichia coli. The two bacterially produced proteins possess GTP-binding activity.

Amino Acid Sequence↗