Enhancement of ultraviolet photorefraction in highly magnesium-doped lithium niobate crystals

We investigate UV photorefraction in Mg-doped LiNbO(3) crystals. Strong UV photorefraction is achieved in highly Mg-doped LiNbO(3) crystals with high two-wave mixing gain, fast response, and low noise. It is also demonstrated experimentally that so-called damage-resistant dopants such as Mg are damage resistant only in the visible and that they will enhance photorefraction in the UV.

[Cloning whole length cDNA of related genes responsible for smooth muscle cells proliferation in atherogenesis and study on its function]

OBJECTIVE

To clone whole length cDNA of the related genes responsible for vascular smooth muscle cell (SMC) proliferation in atherogenesis, and to study its function.

METHODS

ox-LDL was added as a stimulant to the SMC culture medium. Subtractive library was established using subtractive hybridization technique in order to clone the related genes fragments. With the whole length cDNA library established, the whole length cDNA of the related gene was cloned. The protein expressed was studied.

RESULTS

4 new gene fragments and one whole length cDNA were cloned. The new cloned gene is able to express a protein of about 44000 daltons and closely related to the activity of ox-LDL.

CONCLUSIONS

The new cloned gene is considered responsible for SMC proliferation.

[Clearing the doubts of all Wang Bing in the Tang dynasty]

The problem is probed on the clues provided by Si ku ti yao zheng (Analysis on Summary of Books in Four Parts). It is claimed that the Wang bing (*) recommended by Wei Kang and that recommended by Yuwen Rong in Yu Jiaxi's work refer to the same person, both are identical to the time of the author of Su wen. Further, the time of the above 2 Wang Bing(s) and the Wang Bing recorded in lie nu zhuan (Biongraphies of chaste women) as the son of Wang Lin, are also overlapped with the time of the author of Su wen. It is possible that they are the same person. However, the details of the Wang Bing mentioned in Lang guan shi zhu ti ming (inscription for Lang guan Stone Pillar) is unknown. Again, it is unlikely that the Wang Bing (*) is the author of Su wen and can be only a farfetched analogy drawn after Su Fu's poet.

[Gene detection and localization by FISH with short DNA fragment cloned in plasmid]

OBJECTIVE

To establish a method of detecting and localizing newly cloned gene by FISH using short DNA fragment.

METHODS

Bio-14-dATP was incorporated into the target gene cloned in plasmid by nick translation followed by conventional FISH with some modification. By Means of this method, c-met, c-erbB2, 1A6, APC and Rb genes were examined in ovarian and gastric cancer cell lines.

RESULTS

1A6, a newly isolated gene was located at the long arm of one of the C group chromosomes. Oncogene c-met, c-erbB2 and trmor suppressor gene APC, Rb were shown to produce clear-cut hybridization signals in ovarian and gastric cancer cells.

CONCLUSION

Short DNA fragment cloned in plasmid is useful for studies of gene localization, gene deletion and amplification by FISH.

Experimental study of the protection of ischemic preconditioning to spinal cord ischemia

BACKGROUND

Since the advent of ischemic preconditioning in myocardium, more and more attention has been paid to ischemic preconditioning in the central nervous system (CNS). This study was designed to evaluate the protective effect of ischemic preconditioning on spinal cord ischemia.

METHODS

Interventional neuroradiological techniques were used to induce spinal cord ischemia in a rabbit model. Hydrogen electrode technique was used to determine the regional blood flow of the spinal cord. Catecholamines and their metabolites were measured by high performance liquid chromatography (HPLA). Spinal cord evoked potentials were recorded to show spinal cord neurofunction.

RESULTS

After 5 minutes ischemic preconditioning with 20 minutes reperfusion, the regional spinal cord blood flow (rSCBF) was increased, as may be seen by the slight increase of catecholamine, especially NE. This is in positive proportion to the cAMP and indicates the enhancement of the metabolic activities of the spinal cord. After 30 minutes of irreversible ischemia, the great increase in catecholamine caused vascular spasm, endotheliocyte fissure, multiple hemorrhagic suffusion, and necrosis, which would injure the spinal cord as a result. The slight increase of the rSCBF and the maintenance of the rSCBF after irreversible ischemia may enhance the protection of ischemic preconditioning to the spinal cord neurofunction, which was proved by spinal cord evoked potentials (SCEPs).

CONCLUSIONS

Our study showed that 5 minutes of ischemic preconditioning can increase the rSCBF, enhance the tolerance of the spinal cord to irreversible ischemia, and protect the neurofunction of the spinal cord. The biological mechanism of the protective effect of ischemic preconditioning to spinal cord ischemia should be further studied.

Viral diarrhea in children in Beijing, China

A study was undertaken from November 1994 to August 1996 to determine the role of viruses in children (< or =5 years of age) hospitalized at Beijing Children Hospital, Beijing China, for acute diarrhea. Stool samples from diarrheal patients were investigated by ELISA, electron microscopy, and RT-PCR for the presence of rotavirus, calicivirus, astrovirus, and adenovirus. Group A rotavirus was detected in 55.9% of all diarrheal patients and comprised 82.5% of all viruses detected. Group A rotavirus samples were further characterized for their G-type specificity by RT-PCR. Four major G types (1-4) were identified. G1 to G4 accounted for 58.9%, 15.7%, 16.8%, and 6.3%, respectively, of the serotyped samples. Almost all rotavirus infections occurred in children less than 1 year of age, with a significant clustering during the winter months. Group C rotavirus was detected in one 18-month-old child. Astroviruses, caliciviruses, and adenoviruses were detected in 8.5%, 7.6%, and 2.5% of the hospitalized children, respectively. This, the first viral etiological study of childhood diarrhea in China, concludes that rotavirus G1-4 strains play an important role in severe diarrhea in Beijing children.

A specific point mutant at position 1 of the influenza hemagglutinin fusion peptide displays a hemifusion phenotype

We showed previously that substitution of the first residue of the influenza hemagglutinin (HA) fusion peptide Gly1 with Glu abolishes fusion activity. In the present study we asked whether this striking phenotype was due to the charge or side-chain volume of the substituted Glu. To do this we generated and characterized six mutants with substitutions at position 1: Gly1 to Ala, Ser, Val, Glu, Gln, or Lys. We found the following. All mutants were expressed at the cell surface, could be cleaved from the precursor (HA0) to the fusion permissive form (HA1-S-S-HA2), bound antibodies against the major antigenic site, bound red blood cells, and changed conformation at low pH. Only Gly, Ala, and Ser supported lipid mixing during fusion with red blood cells. Only Gly and Ala supported content mixing. Ser HA, therefore, displayed a hemifusion phenotype. The hemifusion phenotype of Ser HA was confirmed by electrophysiological studies. Our findings indicate that the first residue of the HA fusion peptide must be small (e.g., Gly, Ala, or Ser) to promote lipid mixing and must be small and apolar (e.g., Gly or Ala) to support both lipid and content mixing. The finding that Val HA displays no fusion activity underscores the idea that hydrophobicity is not the sole factor dictating fusion peptide function. The surprising finding that Ser HA displays hemifusion suggests that the HA ectodomain functions not only in the first stage of fusion, lipid mixing, but also, either directly or indirectly, in the second stage of fusion, content mixing.

Experimental study on preservation of rat fatty liver

OBJECTIVE

To investigate the effects of cold preservation on rat fatty liver.

METHODS

We observed the changes of portal perfusion pressure, endothelin-1, enzymes release in the effluent and mortality of sinusoid lining cell after 0h, 6h, or 12h preservation respectively and a subsequent 30 min reperfusion in rat fatty liver groups and control groups by using isolated perfused rat liver model. And we compared fatty liver groups with control groups by these indices.

RESULTS

There was no obvious difference between mildly fatty liver group and control group after long time (12h) preservation, between moderately fatty liver group and control group after short time (6h) preservation, between severely fatty liver group and control group without preservation (0h), while preservation reperfusion injury was more severe in moderately fatty liver group than in control group after long time (12h) preservation and in severely fatty liver group than in control group after short time (6h) preservation.

CONCLUSIONS

The authors suggested that a mildly fatty liver donor could be used in the same way as nonfatty liver and a moderately fatty liver donor could be used depending on the time of preservation and the balance of the emergent needs of recipient and donor organ supply, while severely fatty liver donor should be discarded without hesitation.

[Expression of heat shock protein 90 alpha and its effect on the growth of tumor in mice]

OBJECTIVE

To study the effect of hsp90 alpha on the growth of tumor in mice and its mechanism.

METHODS

Hsp90 alpha fusion protein was expressed in E. coli. DBA/2 mice were injected with purified fusion protein, then challenged with L1210 cells. The size of tumor was measured every other day. NK cell activity was detected by 51Cr release assay.

RESULTS

The tumors grew faster while activity NK cell activity of mice was lower in the test mice than that in the control mice.

CONCLUSION

The results suggest that the accelerated tumor growth is probably due to the formation of anti-hsp90 alpha antibody and decreased NK cell activity of mice treated with hsp90 alpha.

[Application of chromosome painting to analysis of structural aberration in five cases]

OBJECTIVE

This article reports that competitive hybridization using entire chromosome specific libraries as probe and human genomic DNA as the competitor allows intense and specific fluorescent staining of human chromosome in metaphase. This general approach is called "chromosome painting".

METHODS

The probes comprising chromosomes 2, 5, 6, 7, 13, 14, X specific libraries were used to analyse five cases which had been suspected of subtle translocation and deletion in karyotype analysis by G-banding of metaphase cells. The authors selected entire chromosome-specific DNA libraries hybridizing with the five cases. Unlabeled human genomic DNA was used to inhibit the hybridization of sequences in the library that bind to multiple chromosome.

RESULTS

The target chromosome was made at least 20 times brighter parunit length than the others. Translocations and deletions were detected clearly in metaphase and were consistent with G-banding. However, the result was clearer and the detection easier, compared with G-banding.

CONCLUSION

Chromosome painting is very powerful for identification of chromosome structural aberrations. Translocation and deletion involving these chromosomes can be strikingly visualized. The hybridization intensity and specificity are such that even very small portions of the involved chromosome can be detected. This technique is especially useful in settings where high-quality banding is difficult.

Specific single or double proline substitutions in the "spring-loaded" coiled-coil region of the influenza hemagglutinin impair or abolish membrane fusion activity

We tested the role of the "spring-loaded" conformational change in the fusion mechanism of the influenza hemagglutinin (HA) by assessing the effects of 10 point mutants in the region of high coiled-coil propensity, HA2 54-81. The mutants included proline substitutions at HA2 55, 71, and 80, as well as a double proline substitution at residues 55 and 71. Mutants were expressed in COS or 293T cells and assayed for cell surface expression and structural features as well as for their ability to change conformation and induce fusion at low pH. We found the following: Specific mutations affected the precise carbohydrate structure and folding of the HA trimer. All of the mutants, however, formed trimers that could be expressed at the cell surface in a form that could be proteolytically cleaved from the precursor, HA0, to the fusion-permissive form, HA1-S-S-HA2. All mutants reacted with an antibody against the major antigenic site and bound red blood cells. Seven out of ten mutants displayed a wild-type (wt) or moderately elevated pH dependence for the conformational change. V55P displayed a substantial reduction (approximately 60- 80%) in the initial rate of lipid mixing. The other single mutants displayed efficient fusion with the same pH dependence as wt-HA. The double proline mutant V55P/ S71P displayed no fusion activity despite being well expressed at the cell surface as a proteolytically cleaved trimer that could bind red blood cells and change conformation at low pH. The impairment in fusion for both V55P and V55P/S71P was at the level of outer leaflet lipid mixing. We interpret our results in support of the hypothesis that the spring-loaded conformational change is required for fusion. An alternate model is discussed.

[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.

En bloc transplation of kidney and whole pancreas with a segment of duodenum in rats

For meeting the clinic needs in simultaneous pancreas and kidney transplantation (SPK), we successfully establish a syngeneic SPK transplatation model in Lewis rats. The results indicate that this model is feasible with a 82.6% successful rate of operation and a 69.6% survival rate in the first postoperative week. In long-term survived rats, the blood supplies are well established, function of the grafts (pancreas and kidney) maintains normal. This model is suitable for theoretical research in SPK transplantation for its reasonable physiology with pancreatic juice drained into intestine and reduced postoperative complications in urinary tract and carbohydrate metabolism.

[The mutual benefit role of pancreas and liver in combined transplantation]

We study observed the mutual benefits of pancreas and liver in combined hepaticopancreatic transplantation in rats. The result indicated that pancreas, when transplanted with liver, could survive for a significantly longer time (13.4 +/- 1.01 days) than it transplanted alone (9.2 +/- 1.14 days) (P < 0.05). The interstitial rejection was mild and its rejection grade was significantly different from that of pancreas transplanted alone (P < 0.05, chi 2 test). The liver, when transplanted with pancreas, regenerated with strong competence and contact structure morphologically compared with liver transplanted alone. We concluded that pancreas could be immunologically protected against rejection and liver can be nutritionalized by pancreas in combined pancreas and liver transplantation.

The mutual benefit role of liver and pancreas in combined transplantation

The present study observed the mutual benefit role of liver and pancreas in combined hepaticopancreatic transplantation in rats. The results indicated that pancreas, when transplanted with liver, could survive for a significant long time (13.4 +/- 1.01 days) than it transplanted alone (9.2 +/- 1.14 days) (P < 0.05, t test). The interstitial rejection was mild and its rejection grade was significantly different from that of pancreas transplanted alone (P < 0.05, X2 test). The liver, when transplanted with pancreas, regenerated with strong competence and contact structure morphologically compared with liver transplanted alone. We think that pancreas could be immunologically protected against rejection and liver can be nutritionalized by pancreas in combined liver and pancreas transplantation.

Generator column determination of aqueous solubilities for non-ortho and mono-ortho substituted polychlorinated biphenyls

Aqueous solubilities of four non-ortho and eight mono-ortho substituted PCBs were determined using a generator-column technique followed by subsequent off-line GC/ECD analysis of the aqueous solutions. The method is based on pumping water through a column containing glass beads coated with the congener being studied and has been used to measure solubilities at room temperature. The method circumvents many of the experimental difficulties encountered with the traditional shake-flask system. Aqueous solubility of 3,3',4,4'-tetrachlorobiphenyl determined by this procedure is compared with data obtained from the shake-flask method and the computational method. The precision of replicate measurements is better than +/- 6.5%. Aqueous solubilities determined for 12 congeners ranged from 6.07 x 10(-11) to 4.47 x 10(-9) mol/L and generally decreased with molecular weight and increased with degree of ortho-chlorine substitution within a molecular-weight class.

Transferability of blood lead determinations by furnace atomic absorption spectrophotometry and continuum background correction

We have examined and proved feasible the transfer of a method for blood lead determination, developed and optimized for a Zeeman-corrected instrument, to a continuum-corrected furnace atomic absorption spectrophotometer. Numerous reference materials analyzed with the continuum-corrected instrument gave results within 10 micrograms/L (0.05 mumol/L) at low values and varied by < 6% at values > 200 micrograms/L (0.97 mumol/L). Forty-four routine human blood specimens were analyzed by the same method with both continuum- and Zeeman-corrected instrumentation, and gave results that agreed within about the same limits as found with reference materials. The day-to-day precision was about 1/5 the accuracy results. The detection limit was approximately 5 micrograms/L (0.025 mumol/L).

Transferability of blood lead determinations by furnace atomic absorption spectrophotometry and continuum background correction

We have examined and proved feasible the transfer of a method for blood lead determination, developed and optimized for a Zeeman-corrected instrument, to a continuum-corrected furnace atomic absorption spectrophotometer. Numerous reference materials analyzed with the continuum-corrected instrument gave results within 10 micrograms/L (0.05 mumol/L) at low values and varied by &lt; 6% at values &gt; 200 micrograms/L (0.97 mumol/L). Forty-four routine human blood specimens were analyzed by the same method with both continuum- and Zeeman-corrected instrumentation, and gave results that agreed within about the same limits as found with reference materials. The day-to-day precision was about 1/5 the accuracy results. The detection limit was approximately 5 micrograms/L (0.025 mumol/L).

Toxic potential of non-ortho and mono-ortho coplanar polychlorinated biphenyls in Aroclors, seals, and humans

Mono-ortho and non-ortho coplanar polychlorinated biphenyls (PCBs) were analyzed in Aroclors, seals, and humans by graphitized carbon, a recently developed HPLC method (Hong et al. 1992b) and high-resolution gas chromatography with electron capture detection (HRGC/ECD). The concentration data were multiplied by potency factors derived from aryl hydrocarbon hydroxylase (AHH) induction to give 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents. The ability to separate coplanar PCBs from the majority of PCBs has allowed the use of TCDD toxicity equivalence to compare the relative dioxin-like potency of PCB residues in the complex mixtures. The most active mixtures, Aroclors 1254, 1248, and 1242, contained 42-54% by weight of chlorine. The results demonstrate that the apparent dioxin-like potency of PCB residues in Aroclors, seals, and humans is dominated by three congeners, 3,3',4,4'-tetra-, 2,3,3'-4,4'-, and 3,3',4,4',5-pentachlorobiphenyl (IUPAC nos. 77, 105, 126).