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Biomedical subjects

F Qi

Publications and source records attributed to F Qi.

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

[Protective effects of ischemic preconditioning on ischemia reperfusion injuries of kidney: experimental studies].

We studied the serum levels of SOD and creatinine(Cr) of venous blood and changes in renal tissue structures under electromicroscope in the ischemia referfusion(I/R), the ischemic preconditioning(PC1, PC2, PC3), and the control groups in rabbits. The results were that the serum levels of SOD and Cr in the I/R group were obviously higher than that in the PC and control groups after one-hour ischemia and one-hour reperfusion(P < 0.001). There were no significant difference in Cr levels between the PC2 and control groups; there were significant degenerate and necrotic changes under the electromicroscope in renal tissues in the I/R group, but there were no significant change in the PC and control groups. The results suggest that PC plays a role in protecting the kidney from injury induced by ischemia and reperfusion.

Animals↗
PubMed1999

[Expression and significance of neuropeptide and neurotensin in the extract of platelet of chronic renal failure patients during hemodialysis].

The aim of this study was to investigate the change of neuropeptide Y(NPY) content and neurotensin (NT) content of the platelet from chronic renal failure (CRF) patients during hemodialysis (HD) and explore its mechanism of action. Platelet was separated from the patients' plasma and the NPY and and NT contents of the platelet and plasma were dynamically observed pre-HD and post-HD. 30 healthy people were chosen as the controls. The results showed the NPY and NT contents of the platelet extract were (58.18 +/- 21.29) ng/10(9) and (25.38 +/- 13.43) ng/10(9) respectively. The NPY content of the platelet extract of the CRF patients was obviously decreased and the NT content of the plasma was obviously increased however, the NT contents of the platelet extract and the plasma were both higher than those in the control group. The NPY content of the platelet extract and NT content of the plasma at the post-HD obviously increased as compared with pre-HD, but the NT content of the platelet extract and the NPY content of the plasma obviously decreased. There was an obvious correlation between NPY and NT. The authors conclude that during the period of CRF, the immunoreactions which mainly involve bio-active substances such as NPY, NT and 5-hydroxytryptamine released by the platelet to interfer the vasoconstrictive effect are the main pathologic factors to induce renal hypertensin and renal vasospasm.

Adult↗
PubMed1998

Insertion of a bovine SMT3B gene in NS4B and duplication of NS3 in a bovine viral diarrhea virus genome correlate with the cytopathogenicity of the virus.

Bovine viral diarrhea virus (BVDV) infection in cattle can lead to the development of a fatal syndrome called mucosal disease (MD). The induction of MD requires co-existence of two biotypes of BVDV: cytopathic (cp) and non-cytopathic (ncp). Studies have shown that in some cases, cp viruses are generated from ncp viruses by cellular gene insertions, duplications or rearrangements in the viral genome. Cellular ubiquitin gene is the most frequently reported insert in BVDV 1. Here we report the finding of a novel cellular gene insertion (termed cSNCINS) in the NS4B gene accompanied by the duplication of NS3 in a cpBVDV genome. The amino acid sequence of the insert is identical to that of the human SMT3B protein and is 98% similar to that of the human SMT3A protein. Both SMT3B and SMT3A proteins are homologues of the yeast SMT3 protein. The cSNCINS protein is encoded by an open reading frame located on a 1150-bp bovine endometrial cDNA fragment. Our results indicate that the cSNCINS is a bovine homologue of the human SMT3B gene and that insertion of the BSMT3B gene together with duplication of NS3 in the viral genome may account for the cytopathogenicity of this virus.

Amino Acid Sequence↗
PubMed1998

Effect of chiral helical force field on molecular helical enantiomers and possible origin of biomolecular homochirality.

Biomolecular homochirality means that the amino acids in proteins, and sugars in nucleic acids, occur in one form: amino acids in L-form and sugars in D-form. So far, the reason why these molecules have such uniform chirality is not known. In this paper, it is suggested that a net natural chiral right-handed helical force field, produced by the Earth's orbital chirality (EOC), could affect the stability of molecular helical enantiomers and make the right-handed helical enantiomers more stable than their left-handed enantiomers, so terrestrial biological systems must select both right-handed helical nucleic acids based on D-sugars, and proteins based on L-amino acids. In given conditions, the maximum energy difference between biomolecular helical enantiomers (deltaEmax=/Eleft-Eright/) caused by the EOC may be calculated theoretically to be in the order: B-DNA > A-RNA > A-DNA >> alpha-protein > beta-protein. Our experimental results strongly supported the hypothesis that the EOC could cause the spontaneous selection and amplification of right-handed helical enantiomers and could be the origin of homochirality on the Earth.

Amino Acids↗
PubMed1998

Functional and morphological damage of endothelium in rabbit ear artery following irradiation with cobalt60.

1. The relaxant actions of acetylcholine and A23187 were examined in the rabbit central ear artery at different intervals following exposure to different doses of radiation with a cobalt60 unit. The artery was irradiated with a dose of 10 Gy, 20 Gy and 45 Gy. Radiation caused dose- and time-dependent impairment of the endothelium-dependent relaxations. The impaired endothelium-dependent relaxations occurred as early as 1 week postirradiation and persisted throughout the experimental period (10 weeks). 2. The endothelium-independent response to sodium nitroprusside was well preserved up to 6 weeks after irradiation. The contractile response to noradrenaline was unaltered by irradiation throughout the experimental period, but in contrast to control vessels, an increase in the sensitivity to noradrenaline in the presence of the nitric oxide synthase (NOS) inhibitor N(G)-nitro-L-arginine was not observed in the irradiated vessels. 3. The impaired endothelium-dependent relaxations in the irradiated vessels were not improved by pretreatment with the NOS substrate L-arginine, the cyclo-oxygenase inhibitor indomethacin or the free radical scavengers superoxide dismutase and catalase. 4. Scanning electron microscopy indicated morphologically intact endothelial cells within the first 4 weeks after irradiation. 5. Western blot analysis showed a significant decrease in the expression of endothelial NOS (eNOS) in the irradiated vessels. 6. These data indicate that endothelial cell function is specifically impaired in the irradiated vessels before morphological endothelial cell damage can be detected. This impairment may be related to diminished eNOS expression.

Animals↗
PubMed1998

Arterial changes following single-dose irradiation.

In this reported experiment, the serial morphologic changes in the rabbit ear central artery, following a single dose of 45 Gy 60Co gamma-ray irradiation, were investigated using light and scanning electron microscopy. Under light microscopy, mild intimal proliferation, disorganization of smooth muscle, and severe perivascular fibrosis were observed. These appeared to be caused by increased intimal cell death and lower repair capability after large single-dose irradiation. Under scanning electron microscopy, the endothelial cells did not show significant morphologic changes during the first 4 weeks. At 6 and 10 weeks after irradiation, the endothelial cells shrank in all directions and detached from the basement membrane. These changes accord with the theory that radiation damage following therapeutic dosage occurs within the DNA of the cell, and that there is no significant change until the cell attempts to divide.

Animals↗
PubMed1998

Structure-activity study of the lantibiotic mutacin II from Streptococcus mutans T8 by a gene replacement strategy.

Mutacin II, elaborated by group II Streptococcus mutans, is a ribosomally synthesized and posttranslationally modified polypeptide antibiotic containing unusual thioether and didehydro amino acids. To ascertain the role of specific amino acid residues in mutacin II antimicrobial activity, we developed a streptococcal expression system that facilitates the replacement of the mutA gene with a single copy of a mutated variant gene. As a result, variants of mutacin II can be designed and expressed. The system was tested by constructing the following mutant peptides: delta N1, V7A, P9A, T10A, T10S, C15A, C26A, and C27A. All of these mutacin II variants except delta N1 and T10A, which were not secreted, were isolated, and their identities were verified by mass spectrometry. Variants P9A, C15A, C26A, and C27A failed to exert antimicrobial activity. Because the P9A and T10A variants comprise the "hinge" region of mutacin II, these observations suggest that in addition to the thioether and didehydro amino acids, the hinge region is essential for biological activity and biosynthesis or export of the peptide. Tandem mass spectrometry of the N-terminal part of the wild-type molecule and its C15A variant confirmed that the threonine at position 10 is dehydrated and present as a didehydrobutyrine residue. This analysis of the active T10S variant further suggested that a didehydro amino acid at this position is specific for antimicrobial activity and that the biosynthetic machinery does not discriminate between threonine and serine. In contrast, the lack of production of mutacin variants with alanine substituted for threonine at position 10, as well as the deletion of asparagine at the N terminus (delta N1), indicates that specific residues in the propeptide may be crucial for certain steps in the biosynthetic pathway of this lantibiotic.

Amino Acid Sequence↗
PubMed1998

Diacylglycerol kinase is involved in regulation of expression of the lantibiotic mutacin II of Streptococcus mutans.

Genetic characterization of a Tn916 transposon mutant, Streptococcus mutans T8-1, defective in mutacin II production, revealed that the transposon was inserted into the 3' region of a diacylglycerol kinase (dgk) gene. The insertion occurred in the same region as described for another S. mutans mutant, GS5Tn1, which was altered in its ability to respond to environmental stress (Y. Yamashita, T. Takehara, and H. K. Kuramitsu, J. Bacteriol. 175:6220-6228, 1993). Quantitative primer extension from the mutacin structural gene mutA showed a decreased level (about eightfold) of mutA transcription for mutant T8-1. Mutacin production was restored by transforming mutant T8-1 with integration vector pVA891 containing an intact dgk gene. These data indicated that the full-length dgk gene product along with the mutacin biosynthetic operon are required for the production of the mutacin II lantibiotic.

Amino Acid Sequence↗
PubMed1998

[The effect of detrusor instability secondary to benign prostatic hypertrophy on the density of acetylcholinesterase-containing nerves].

OBJECTIVE: To study the effect of detrusor instability secondary to benign prostatic hypertrophy (BPH) on the density of cholinesterase-containing nerve in detrusor samples. METHOD: Our present study included 3 groups confirmed by urodynamic evaluation. They were control group (8 cases), obstructive detrusor stability group (7), and obstructive instability group (12). The specimens were obtained from the dome of bladder. The AchE-containing nerves were demonstrated by the method of Karnovsky-Roots staining and AchE silver staining. The density of AchE containing detrusor nerves in specimens was examined with sterologic techniques. RESULT: The density of AchE-containing nerves in the obstructive detrusor instability group and the stability group was significantly decreased as compared with the control group (P < 0.01). The density of AchE positive nerves were also significantly decreased in the obstructive instability group as compared with the obstructive stability group (P < 0.05). CONCLUSION: Detrusor instability secondary to BPH obstruction is related to the decrease of cholinergic innervation density in the detrusor muscles.

Acetylcholinesterase↗
PubMed1998

[Math-model of efficient cultivation of Angelica sinensis].

Using two-time general rotation-constitution design, the math-mdele has been founded about Angelica sinensis prodution efficiency and quantity of nitrogen, phosphorus and potassium to use by doing experiments in many different spots and production demonstration for testing and verifying. Accordin to the modle, computer is used to simulate the better, through which people can get fresh Chinese angelica over 500 Kg per mu and also net income over 500 yuan per mu. It shows that this is the best combination. 95% density riliability for this plan is 6860-7600 plants, pure nitrogen 18.75-22.2 Kg, P2O5 9.1-11.1 Kg and K2O 4.46-5.37 Kg One mu. Proportion for nitrogen, phosphorus, potassium is 1:0.49:0.24.

Angelica↗
PubMed1996

In vitro assessment for vascular selectivity of a new dihydropyridine derivative, NB-818.

The vascular selectivity of NB-818 (isopropyl methyl 2-carbamoyloxymethyl-6-methyl-4-(2,3-dichlorophenyl)-1,4-dihydropyridine -3, 5-dicarboxylate), a newly synthesized dihydropyridine derivative, was evaluated in in vitro experiments. NB-818 and nifedipine concentration dependently caused a relaxant effect in rabbit femoral arteries precontracted with 60 mM K+, a negative inotropic effect in guinea-pig papillary muscles, and a negative chronotropic effect in guinea-pig right atria. The onset of these inhibitory effects of NB-818 was much slower than that of nifedipine when compared at concentrations producing the same inhibition. The relaxant effect of NB-818 was about 10 times more potent than that of nifedipine, while the negative inotropic effect of NB-818 was about 100 times less potent than that of nifedipine. As a result, NB-818 showed about 300 times higher vascular selectivity than nifedipine. The two drugs exhibited a similar potency for the negative chronotropic effect. In a whole-cell configuration with voltage clamp, the blocking effect of NB-818 on L-type Ca2+ current (ICa) in guinea-pig ventricular cells appeared much more slowly than that of nifedipine and was hardly washed out. The potency of NB-818 to block ICa was markedly enhanced under depolarized conditions (i.e. at a holding potential of -30 mV) compared to that under polarized conditions (i.e. at a holding potential of -70 mV). Such a voltage-dependent blocking action on ICa was less pronounced for nifedipine. These results indicate that NB-818 is a slow-acting Ca2+ channel antagonist with much high vascular selectivity. Its vascular selectivity may be at least in part related to the marked voltage-dependent inhibition of ICa.

Animals↗
PubMed1996

An anatomic study of the latissimus dorsi-rib flap: an extension of the subscapular combined flap.

The anatomy of the vascular perforators between the latissimus branch of the thoracodorsal vessels and the lateral branch of the dorsal rami of the intercostal vessels was studied in a series of 10 dissections in 5 preserved cadavers to develop the latissimus dorsi myocutaneous flap combined with a vascularized rib. The distances between the communicating perforators and the spinous process and the iliac crest, which become a good guide for design of the rib flap, were measured. An extension of the combined flap including the scapular osteocutaneous flap, latissimus dorsi myocutaneous flap, and vascularized eleventh and twelfth ribs that is nourished by a "single" subscapular vascular system was demonstrated. This technique, which provides a large amount of skin, muscle, and bone, is very effective for reconstruction of an extended composite maxillary and mandibular defect.

Aged↗
PubMed1996

Effects of egtazic acid and calcimycin on synthesis of DNA and collagen in cultured human lung fibroblasts.

AIM: To study the effects of egtazic acid (EA) and calcimycin (Cal) on the synthesis of DNA and collagen in cultured human lung fibroblasts (HLF). METHODS: The synthesis of DNA and collagen was determined by measuring the incorporation of [3H]TdR and [3H]proline of HLF respectively. RESULTS: The collagen synthesis increased markedly 24 h after exposure to both EA (0.05-4 mmol.L-1) and Cal (0.25-20 mumol.L-1), and that there was no obvious change in DNA synthesis. After 36-48-h exposure, both DNA and collagen syntheses decreased in the groups of EA (1, 2, and 4 mmol.L-1); the DNA synthesis was also suppressed in Cal groups in a concentration-dependent manner, whereas collagen synthesis decreased only in Cal (10 and 20 mumol.L-1). CONCLUSION: Extracellular Ca2+ influx into fibroblasts increased collagen production, However, the DNA synthesis was suppressed when the cytosolic Ca2+ was too high or too low.

Biological Transport, Active↗
PubMed1995

Regulation of codBA operon expression in Escherichia coli by UTP-dependent reiterative transcription and UTP-sensitive transcriptional start site switching.

Reiterative transcription is the repetitive addition of nucleotides to the 3' end of a nascent transcript due to slippage between the transcript and DNA template. Recently, we showed that pyrimidine-mediated regulation of pyrBI operon expression in Escherichia coli occurs, in part, through a mechanism in which induction of UTP-dependent reiterative transcription within the initially transcribed region prevents downstream extension of the nascent transcript to include structural gene sequences. In this study we demonstrate that pyrimidine-mediated regulation of codBA operon expression in E. coli also involves UTP-dependent reiterative transcription during initiation; however, the mechanism is different from that of the pyrBI operon. The initially transcribed region of the codBA promoter contains the sequence GATTTTTTG (non-template strand). Our results show that transcription is initiated primarily at the first two bases designated G7 and A8 (counting from the -10 region). When transcripts are initiated at position A8, UTP-dependent reiterative transcription always occurs within the run of T residues in the initially transcribed region. The AUUUUn (where n = 1 to > 15) transcripts produced by this reaction are not extended productively to include downstream codBA sequences. In contrast, most transcripts initiated at position G7 do not engage in reiterative transcription and can be elongated normally. Characterization of a codBA promoter mutation that prevents reiterative transcription showed that this reaction is required for virtually all pyrimidine-mediated regulation of operon expression and that UTP levels control the selection of the G7 and A8 transcriptional start sites. These results suggest a model for regulation in which high intracellular levels of UTP favor transcriptional initiation at position A8 and thus the accompanying reiterative transcription, which together preclude initiation at position G7. Low levels of UTP inhibit initiation at position A8 and the associated reiterative transcription, thereby allowing high levels of initiation at position G7 and operon expression. Our results also indicate critical sequence requirements for reiterative transcription, which are important for understanding the mechanism of this reaction as well as for identifying other promoters at which this reaction may occur. Of particular interest is the indication that an RNA:DNA hybrid forms during transcriptional initiation and the strength of this hybrid controls the extent of reiterative transcription.

Bacterial Outer Membrane Proteins↗
PubMed1995

An anatomic study for the rectus abdominis myocutaneous flap combined with a vascularized rib.

The anatomy of the vascular connections between the eighth intercostal vessels and the deep epigastric vessels was studied in a series of 20 dissections in 10 preserved cadavers to develop the rectus abdominis myocutaneous flap combined with a vascularized rib. The distance between the point where the eighth intercostal vessels attached to the costal margin and the xiphoid process and the arcuate line, which become a good guide for design of the flap, was measured. The average length of the vascular pedicle of a vascularized rib was over 10 cm. Possible clinical uses of this compound flap for reconstruction of a composite maxillary or mandibular defect are described.

Abdominal Muscles↗
PubMed1995

Controlling cancerous pain with analgesic powder for cancers.

Analgesic powder for cancers, composed of more than 20 Chinese drugs, was applied externally to 91 patients with various kinds of cancers for management of cancerous pain. The results showed that it was remarkably effective in 42 cases, fairly effective in 22, effective in 22, and ineffective in 5, the total effective rate being 94.51%. Animal experiments indicated that the pain threshold was evidently higher in mice treated with this powder on the site of femoral artery of the hind limbs than that of the controls without application of this powder.

Administration, Cutaneous↗