[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.

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.

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.

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.

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.

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.

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.

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.

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.

Effects of tetrandrine and chlorpromazine on synthesis of collagen and hyaluronic acid in cultured human lung fibroblasts

AIM

To study the effects of tetrandrine (Tet) and chlorpromazine (Chl) on synthesis of collagen and hyaluronic acid (HA) in cultured human lung fibroblasts (HLF).

METHODS

The synthesis of collagen and HA was assessed by measuring the incorporation of [3H]proline and radioimmunoassay.

RESULTS

Both Tet (5-80 mumol L-1) and Chl (10-40 mumol L-1) diminished the collagen synthesis in a concentration-dependent manner. The suppression was aggravated at 36-48 h. The HA content in the supernatant of culture also decreased gradually with the increasing dosage of Tet or Chl after 24-h exposure. There was no obvious toxic effect of Tet on HLF cells at 5-20 mumol L-1.

CONCLUSION

Tet 5-20 mumol L-1 decreased the production of collagen and HA without obvious toxity on HLF, suggesting that Tet could be a hopeful anti-fibrosis drug.

Natural recombination in bovine viral diarrhea viruses

BVDV isolates exist as two biotypes differentiated at the molecular level by production of a p80 polypeptide. Insertions consisting of host cell sequences and/or duplicated and rearranged viral sequences have been observed in the portion of the genome coding for the p80 polypeptide in some, but not all, cytopathic BVDV. The significance of these insertions to biotypic expression has yet to be demonstrated. It has been hypothesized that recombination results in the production of the p80 polypeptide by introduction of a cleavage site into a precursor polypeptide or the introduction of a second copy of the p80 gene. Because inserts have not been identified in all cytopathic BVDV examined, it appears that recombination may not be the only mechanism involved in biotypic determination.

The nucleotide sequence of the 5'-untranslated region of bovine viral diarrhoea virus: its use as a probe in rapid detection of bovine viral diarrhoea viruses and border disease viruses

A 289 bp cDNA fragment from the 5'-untranslated region (UTR) of 16 bovine viral diarrhoea virus (BVDV) isolates was amplified by reverse transcription and polymerase chain reaction, and sequenced by dideoxy DNA sequencing. The sequence showed greater than 90% homology between the isolates and BVDV NADL in this region, and greater than 97% homology within a 72 base sub-region (nt 314-386). The 289 bp fragment was then used as a probe for rapid detection of BVDV and border disease virus (BDV) from cell culture samples by dot-blot hybridization. This probe hybridized to 100% of BVDV isolates (n = 78) and 100% of BDV isolates (n = 9), but not to the uninfected BT cells or other bovine infectious agents. A shorter probe from the more conserved sub-region also was tested for hybridization with some of the isolates, and the results were similar to those using the longer probe. These results suggest that the 5'-UTR is highly conserved among BVDV and BDV isolates, and may be used as a potential probe for rapid detection of BVDV and BDV in clinical and cell culture samples from cattle and sheep.

Analysis of the bovine viral diarrhea virus genome for possible cellular insertions

Mucosal disease is the most severe disease resulting from bovine viral diarrhea virus (BVDV) infection in cattle. Two biotypes of BVDV may be isolated from animals with mucosal disease: cytopathic (cp) and noncytopathic (ncp). These "pairs" of cp/ncp viruses are often closely related and it has been suggested that the cp virus arises from a ncp virus by insertion of cellular RNA in the p125 region of the BVDV genome. We have used four pairs of cp/ncp BVDV isolated from cattle with mucosal disease, to examine the genomic sequence of the region of the genome coding for the nonstructural protein p125 (processed to p54/p80 in cp viruses) by PCR analysis and sequencing. We did not detect any cellular gene insertions in any of the four ncp viruses; however, we found a large duplication of the p80 gene and a ubiquitin gene insertion in three of the four cp isolates. Our results suggest that cellular RNA insertions in the p125 region may contribute significantly to the cytopathogenicity of BVDV. However, this does not appear to be the only mechanism of cytopathogenicity as we did not detect any insertions or duplications in one of the cp viruses. Comparison of the DNA sequence in the p80 region revealed greater homology within the "pairs" than to NADL, which lend further support to the hypothesis that a cp virus is originated from a ncp virus.