[Preparation and analysis of pure type II collagen from porcine articular cartilage]

This investigation was aimed at the preparation of pure type II collagen from porcine articular cartilage and the feasible method for producing type II collagen in bulk. After dispersal of the porcine articular cartilage, the proteoglycans were extracted by guanidinium hydrochloride and dissolved by pepsin in acid solvent. The contaminants including denatured and degraded protein and other collagen was removed via the repeated procedure of purification. For obtaining the purer type II collagen, the chromatography with sepharose H. P. Column was also used. The purity of the sample was compared with the type II collagen produced by Sigma Company. Both type II collagens were characterized by SDS-PAGE electrophoresis, amino acid analysis and maximal violet chromatography, and all of the results accorded with the standard photograph in the references. The purity of the sample was higher than that of the product of Sigma Company. This prepared collagen of type II is a product of high purity. The raw materials are the common porcine articular cartilage, which is rich in resource and low in cost. Therefore, it is suitable to produce type II collagen in batches.

Room-temperature ionic liquids: a novel versatile lubricant

Alkylimidazolium tetrafluoroborates are promising versatile lubricants for the contact of steel/steel, steel/aluminium, steel/copper, steel/SiO2, Si3N4/SiO2, steel/Si(100), steel/sialon ceramics and Si3N4/sialon ceramics; they show excellent friction reduction, antiwear performance and high load-carrying capacity.

[The transferability of acetochlor and butachlor in soil]

The transferability of acetochlor and butachlor in soil was studied by soil thin layer chromatography. Acetochlor and butachlor were dropped on the glass plate and spreaded soil on the glass plate was collected per 2 cm, then acetochlor and butachlor were analyzed quantitatively by HPlC. When river water was as the spread solution, Rf(relative flow) of acetochlor and butachlor in the Haidian loam were 0.116 and 0.031 respectively, Rf of acetochlor and butachlor in the Baiyangdian sandy loam were 0.147 and 0.032 respectively. When 30 mg.L-1 dodecylbenzene sulfonic acid sodium salt solution was as the spread solution, Rf of acetochlor and butachlor in the Haidian loam were 0.159 and 0.034 respectively. Acetochlor's transferability was weak and the gradation of its transferability was II grade, while butachlor's was more weak and the gradation was I grade. Anionic surfactant solution can promote pesticides to transfer. Cationic surfactant solution can impede pesticides to transfer.

Prevalence of iron transport gene on pathogenicity-associated island of uropathogenic Escherichia coli in E. coli O157:H7 containing Shiga toxin gene

Uropathogenc Escherichia coli (UPEC) CFT073 has a pathogenicity-associated island (PAI(CFT073)), which causes pyelonephritis and cystitis. Using PCR method, we found the prrA gene of PAI(CFT073) in E. coli O157:H7 EDL933. Further detailed PCR screening of 38 open reading frames, the right and left junction sequences of PAI(CFT073), revealed that it is the prrA-modD-yc73-fepC gene cluster but not the PAI(CFT073) present in E. coli O157:H7 EDL933. A rapid preliminary analysis suggested that the prrA-modD-yc73-fepC gene cluster of the PAI(CFT073), is present in 43 strains of E. coli O157:H7 containing Shiga toxin (Stx) gene but absent in 19 strains of E. coli O157:H7 without Stx gene. A strict co-occurrence of the prrA-modD-yc73-fepC gene cluster and Stx genes was observed, regardless of their origin. The prrA-modD-yc73-fepC gene cluster encode proteins probably involved in iron uptake system, which strongly suggests the importance of iron metabolism in the Stx-mediated virulence. In addition, the prrA-modD-yc73-fepC gene cluster may be used as a diagnostic marker to distinguish E. coli O157:H7 strains containing Stx gene from that without Stx gene, and possibly to quickly detect other pathogenic gram-negative bacteria containing the Stx gene.

Dynamics and mechanism of ultraviolet photolysis of atrazine on soil surface

The photolysis of atrazine in the soil surface under UV light and the factors affecting this has been studied. A rate constant of 0.09-0.17 min-1, photolytic depth of 0.1-0.3 mm and half-life of 4-8 min were determined. The results show that soil granularity, pH, humidity, organic content, humic acid and surface-active agents could affect the photolysis of atrazine in soil. GC-MS showed three photolytic products: 1-sec-butyl-4,4-diethyl-1-tetrazene, N2,N4-diethyl-6-methyl-1,3,5-triazine-2,4-diamine and 6-chloro-N2-propyl-1,3,5-triazine-2,4-diamine. The mechanism of the photolytic process is discussed.

Oral HCFU for prevention of hepatic metastasis in an experimental colorectal carcinoma

BACKGROUND

An animal experimental study was performed to clarify the preventive effect of oral HCFU (1-hexylcarbamoyl-5-fluorouracil) on hepatic metastasis.

MATERIALS AND METHODS

A total of 180 BALB/C mice received intraportal injection of Colon26 cancer cells followed by oral daily administration of HCFU to 5 groups divided according to the dose of HCFU, ranging from 0 (controls) to 7.5 mg/Kg for 21 days. These groups were independently assigned to 3 sets to investigate survival rates and degree of hepatic metastasis.

RESULTS

Mean survivals in the treated groups were statistically longer than the controls except the 7.5 mg/Kg group. HCFU 7.5 and 5 mg/Kg groups showed the minimum liver weight on the 12th and 16th day, respectively these were significantly smaller than those of controls (p < 0.0001 in both).

CONCLUSION

It is considered that oral HCFU could effectively suppress hepatic metastasis of the colon26 cancer cells and prolong the life of animals. This finding suggests the promising clinical application of oral HCFU for colorectal cancer after curative resection.

[Multimedia environmental behavior of herbicide atrazine]

In the paper, taking the Baiyangdiang Lake area as a study field, on the basis of soil characterization, environmental monitoring, and studies of adsorption, biodegradation, hydrolysis and photolysis, the atrazine concentrations in soil, groundwater and corn plant during 30 years were predicted by multimedia environmental fugacity model.

Expression of extracellular calcium-sensing receptor in human osteoblastic MG-63 cell line

We have previously shown the expression of the extracellular calcium (Ca2+o)-sensing receptor (CaR) in osteoblast-like cell lines, and others have documented its expression in sections of murine, bovine, and rat bone. The existence of the CaR in osteoblasts remains controversial, however, since some studies have failed to document its expression in the same osteoblast-like cell lines. The goals of the present study were twofold. 1) We sought to determine whether the CaR is expressed in the human osteoblast-like cell line, MG-63, which has recently been reported by others not to express this receptor. 2) We investigated whether the CaR, if present in MG-63 cells, is functionally active, since most previous studies have not proven the role of the CaR in mediating known actions of Ca2+o on osteoblast-like cells. We used immunocytochemistry and Western blotting with the specific, affinity-purified anti-CaR antiserum 4637 as well as Northern blot analysis and RT-PCR using a riboprobe and PCR primers specific for the human CaR, respectively, to show readily detectable CaR protein and mRNA expression in MG-63 cells. Finally, we employed the patch-clamp technique to show that an elevation in Ca2+o as well as the specific, allosteric CaR activator NPS R-467 (0.5 microM), but not its less active stereoisomer NPS S-467 (0.5 microM), activate an outward K+ channel in MG-63 cells, strongly suggesting that the CaR in MG-63 cells is not only expressed but is functionally active.

Soluble recombinant endostatin purified from Escherichia coli: antiangiogenic activity and antitumor effect

Endostatin is a potent and specific antiangiogenic protein capable of inhibiting the growth of murine and xenotransplanted human tumors. Thus far, however, recombinant endostatin prepared from Escherichia coli is insoluble after purification and therefore inappropriate for clinical settings. A soluble form of endostatin is available from a yeast system with relatively low yield and high cost, which has made it difficult to produce endostatin in quantities sufficient for extensive clinical evaluation. In this study, we developed a protocol to generate soluble recombinant murine endostatin from E. coli at a yield of 150 mg/liter-culture and 99% purity. The in vivo antiangiogenic and antitumor activities of the soluble recombinant endostatin are equally as potent as those of the previously published insoluble form. A similar protocol may be used to produce soluble human endostatin.

High-pathogenicity island of Yersinia spp. in Escherichia coli strains isolated from diarrhea patients in China

The high-pathogenicity island (HPI) of Yersinia has been observed in 93% of 60 enteroadhesive Escherichia coli strains and 80% of E. coli strains isolated from blood samples. In the present study we investigated 671 fecal samples from patients with diarrhea in Shandong Province, China, and isolated HPI-harboring E. coli from 6. 26% of the samples. The isolation rates for patients with diarrhea in three age groups, 10 to 20, 30 to 40, and 50 to 60 years, were 6. 70, 12.35, and 10.81%, respectively. Therefore, HPI-harboring E. coli is the third most frequently isolated enteric pathogen from patients with diarrhea. Vomiting and abdominal pain were recorded for 33.33 and 66.67% of the patients, respectively. Stools with blood were observed for 9.52% of the patients. Twenty-four of 42 (57%) patients experienced a temperature over 37.4 degrees C. These observations indicate that HPI-harboring E. coli is one of the major causes of diarrheal disease in China and that the clinical symptoms caused by HPI-harboring E. coli differ from those caused by enteroadhesive E. coli.

Galpha(i2) but not Galpha(i3) is required for muscarinic inhibition of contractility and calcium currents in adult cardiomyocytes

Parasympathetic stimulation of the heart acts through M(2)-muscarinic acetylcholine receptors to regulate ion channel activity and subsequent inotropic status. Although muscarinic signal transduction is mediated via pertussis toxin-sensitive G proteins Galpha(i/o), the specific signal transduction requirements of Galpha(i2) and Galpha(i3) in mediating muscarinic regulated L-type calcium currents (I(Ca, L)), intracellular calcium, and cell contractility remain to be determined. Adult ventricular myocytes were isolated from Galpha(i2)-null mice, Galpha(i3)-null mice, and their wild-type littermates. Cell shortening, intracellular calcium levels, and I(Ca, L) were all measured in response to isoproterenol, a beta-adrenergic receptor agonist, and carbachol, a cholinergic receptor agonist. With isoproterenol stimulation, myocytes from all groups demonstrated a marked increase in calcium currents, correlating with augmented intracellular calcium transient amplitude and cell shortening. Carbachol significantly attenuated the isoproterenol response in wild-type and Galpha(i3)-null cells but had no effect in Galpha(i2)-null cells. This study demonstrates that Galpha(i2), but not Galpha(i3), is required for muscarinic inhibition of the beta-adrenergic response in adult murine ventricular myocytes.

Development of an affordable diaphragmatic pump for cardiopulmonary bypass: an in vivo evaluation

A new diaphragmatic pump (L-Y pump) and its drive unit were developed in our institute. The pump has a priming volume of 80 ml. The pump housing is 72 mm in diameter and 42 mm in height. Its total weight is 139 g. To assess and confirm the function and controllability of this pump, comparative studies of cardiopulmonary bypass (CPB) with L-Y pump (group A) and conventional roller pump (Group B) were performed using dogs. Both pumps provided pump flow of 90 to 100 ml/kg/min. The hemodynamics of both groups were stable and within the normal range. No leakage or thrombus formation was observed in the L-Y pump. All biochemistry data showed no significant differences between the 2 groups. This data demonstrated low plasma-free hemoglobin levels in the L-Y pump group; after 120 min of CPB, mean plasma free hemoglobin levels were 48.7 +/- 8.6 mg/dl in the roller pump group and 21.4 +/- 7.1 mg/dl in the L-Y pump group, and minimal hemolysis was indicated. In conclusion, this L-Y pump and its controller system might be useful for CPB in terms of its low hemolysis and good pump quality. This pump demonstrated easy manipulation, good controllability, and provided a sufficient pulsatile flow. This pump is suitable not only for CPB, but also as a long-term circulatory support system.

Defective extracellular calcium (Ca(o))-sensing receptor (CaR)-mediated stimulation of a Ca(2+)-activated potassium channel in glioblastoma cells transfected with a dominant negative CaR

Glioblastoma cells exhibit several forms of sensitivity to extracellular calcium (Ca(o)) that might be conferred by the Ca(o)-sensing receptor (CaR) that is intimately involved in the maintenance of Ca(o) homeostasis by various cell types. This receptor is expressed in human glioblastoma cell line, U87, and here we show that CaR activators stimulate a Ca(2+)-activated potassium (K(+)) channel (CAKC) with a conductance of 140 pS. The responses to CaR activators, however, were blunted in U87 cells transfected with a CaR bearing an inactivating mutation (R185Q) that has previously been shown to exert a dominant negative (DN) action on the wild type receptor. Raising Ca(o) from 0.75 to 2.0 mM or addition of a polycationic CaR agonist, each activated CAKC in nontransfected wild type and empty vector-transfected U87 cells, while they had little or no effect on channel activity in cells expressing the DN CaR (DN-CaR cells). In nontransfected wild type and empty vector-transfected cells, the specific 'calcimimetic' CaR activator, NPS R-467, stimulated the channel, while its less active stereoisomer, NPS S-467, did not. In DN-CaR cells, in contrast, NPS R-467, had no effect on channel activity, suggesting defective coupling of the CaR to this ion channel. CaR-mediated stimulation of these K(+) channels could lead to membrane repolarization and related changes in cellular function under normal conditions. Since the R185Q mutation in the CaR produces a more severe phenotype in humans than most inactivating mutations of this receptor, some of its clinical consequences could potentially result from abnormal CaR-dependent channel functioning.

[The research and manufacture of the pneumatic left ventricular assist pump]

The manufacturing methods and testing results of the pneumatic left ventricular assist pump(L-Y pump) are introduced in this paper. The results demonstrate that L-Y pump is reliable, biocompatible and in keeping with the clinical requirements.

Design of experiment and data analysis by JMP (SAS institute) in analytical method validation

Validation of an analytical method through a series of experiments demonstrates that the method is suitable for its intended purpose. Due to multi-parameters to be examined and a large number of experiments involved in validation, it is important to design the experiments scientifically so that appropriate validation parameters can be examined simultaneously to provide a sound, overall knowledge of the capabilities of the analytical method. A statistical method through design of experiment (DOE) was applied to the validation of a HPLC analytical method for the quantitation of a small molecule in drug product in terms of intermediate precision and robustness study. The data were analyzed in JMP (SAS institute) software using analyses of variance method. Confidence intervals for outcomes and control limits for individual parameters were determined. It was demonstrated that the experimental design and statistical analysis used in this study provided an efficient and systematic approach to evaluating intermediate precision and robustness for a HPLC analytical method for small molecule quantitation.

A high-resolution (13)C 3D CSA-CSA-CSA correlation experiment by means of magic angle turning

It is shown in this paper that a previously reported 90 degrees sample flipping (13)C 2D CSA-CSA correlation experiment may be carried out alternatively by employing constant slow sample rotation about the magic angle axis and by synchronizing the read pulse to 13 of the rotor cycle. A high-resolution 3D CSA-CSA-CSA correlation experiment based on the magic angle turning technique is reported in which the conventional 90 degrees 2D CSA-CSA powder pattern for each carbon in a system containing a number of inequivalent carbons may be separated according to the isotropic chemical shift value. The technique is demonstrated on 1,2,3-trimethoxybenzene in which all of the overlapping powder patterns that cannot be segregated by the 2D CSA-CSA experiment are resolved successfully by the 3D CSA-CSA-CSA experiment, including even the two methoxy groups (M(1) and M(3)) whose isotropic shifts, confirmed by high-speed MAS, are separated by only 1 ppm. A difference of 4 ppm in the principal value component (delta(33)) between M(1) and M(3) is readily obtained.

Generation of a polymorphic marker linked to thymoma susceptibility gene of rat 1 by genetically-directed representational difference analysis

BUF/Mna (BUF) is a rat strain susceptible to spontaneous development of thymomas. We have previously shown that the thymoma susceptibility is controlled principally by a dominant susceptibility gene located on chromosome 7, thymoma susceptibility gene of rat 1 (Tsr1). To generate genetic markers tightly linked to Tsr1, we performed genetically directed representational difference analysis (GDRDA) with three combinations of the tester and driver DNAs. From 124 ¿ACI/NMs x (BUF x ACI/NMs) F1¿ backcross rats, 12 rats with the ACI/BUF genotype in the Tsr1 region (A/B rats) and 13 rats with the ACI/ACI genotype in the region (A/A rats) were selected, and their DNAs were pooled, respectively. Three kinds of tester DNAs, i) inbred BUF, ii) (BUF x ACI)F1, and iii) the pool from the A/B rats, were subtracted by the driver DNA prepared from the pool of the A/A rats. The three combinations yielded one, two, and one polymorphic marker(s), respectively. One marker, D7Ncc28, was isolated commonly by the three combinations of subtraction, and another marker, D11Ncc12 was isolated only by the second combination. Linkage analysis demonstrated that D7Ncc28 was located in the 8.3 cM region where Tsr1 has been mapped. The three combinations of subtraction were shown to be almost equally capable of isolating polymorphic markers in a specific chromosomal region.

Enhanced expression of extracellular calcium sensing receptor in monocyte-differentiated versus undifferentiated HL-60 cells: potential role in regulation of a nonselective cation channel

Human promyelocytic leukemia cells (HL-60) have been used widely as a model for studying the differentiation of hematopoietic progenitor cells in vitro. After treatment with phorbol-12-myristate-13-acetate (PMA) or 1,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)], HL-60 cells differentiate into cells with the phenotype of monocytes/macrophages. We previously showed that peripheral blood monocytes and the murine J774 monocytic cell line express the CaR, and myeloid progenitors in the bone marrow and myeloid cells in peripheral blood other than monocytes express lower levels of the CaR. Therefore, we investigated whether undifferentiated HL-60 cells express a functional G protein-coupled, extracellular calcium (Ca(2+)(o))-sensing receptor (CaR) and if the expression of the CaR increases as these cells differentiate along the monocytic lineage. The use of reverse transcription-polymerase chain reaction (RT-PCR) with CaR-specific primers, followed by sequencing of the amplified products, identified an authentic CaR transcript in undifferentiated HL-60 cells. Both immunocytochemistry and Western blot analysis using a CaR-specific antiserum detected low levels of CaR protein expression in undifferentiated HL-60 cells. The levels of CaR protein increased considerably following treatment of the cells with PMA (50 nM) or 1,25(OH)(2)D(3) (100 nM) for 5 days. Northern analysis using a CaR-specific riboprobe identified CaR transcripts in undifferentiated HL-60 cells, but CaR mRNA levels did not change appreciably after treatment with either agent, suggesting that upregulation of CaR protein occurs at a translational level. PMA-treated HL-60 cells expressed a nonselective cation channel (NCC), and the calcimimetic CaR activator, NPS R-467, but not its less active stereoisomer, NPS S-467, as well as the polycationic CaR agonist, neomycin, activated this NCC, demonstrating that the CaR expressed in these cells is functionally active. Therefore, HL-60 cells exhibit an increase in CaR protein expression, occurring at a translational level during their differentiation into cells with a monocyte/macrophage phenotype in response to treatment with PMA or 1, 25(OH)(2)D(3), which is functionally linked to activation of a nonselective cation channel.

Spin-locking mechanism of spin I = 3/2 quadrupolar nuclei undergo magic angle spinning

The spin-locking mechanism of the spin I = 3/2 quadrupolar nuclei under magic angle spinning (MAS) has been theoretically and experimentally investigated, and the criterion of adiabatic passage around zero-crossings of the quadrupole splitting was inferred from the time-dependent Shrödinger equation in this article. The theory, numerical simulations, and experiments conducted in this work all indicated that second-order quadrupole interaction and off-resonance play important roles in the spin-locking of the quadrupolar nuclei, and they were responsible for the great loss of the spin-locking signals. The spin-locking for a spin I = 3/2 nucleus might be achieved by minimizing the effect of the second-order quadrupole interaction by using a radio frequency (RF) offset. This offset was realized by setting the RF to the opposite position of the isotropic second-order quadrupolar shift of single quantum coherences.

[Detection of Escherichia coli strains harboring pathogenicity island of Yersinia enterolitica in diarrheal patients and animals in China]

OBJECTIVE

To investigate the prevalence of Escherichia coil strains harboring high pathogenicity island of Yersinia enterocolitica in diarrhea patients, animals, food samples and resulted clinical symptoms.

METHODS

Colony hybridization, DNA dot hybridization and polymerase chain reaction (PCR) were used.

RESULTS

HPI - harboring E. coli were found in the strains isolated in various provinces of China. The isolation rates were 27.05% (436/1,612) in the strains isolated from diarrhea patients, 10.23% (9/88) in the strains isolated from food samples and 5.71% (16/280) in the strains isolated from feces of cattle and pigs. Typical clinical symptoms of diarrhea caused by HPI - harboring E, coli were inappetency, abdominal pain, shiver and vapidity. Patient's temperature was usually normal or low. Over six episodes of diarrhea was frequently observed, of which most were unformed stools with mucous.

CONCLUSION

E. coli strains harboring high - pathogenicity - island of Yersinia species were frequently isolated from diarrhea patients, animals and food samples as well, which might be one of the major causes of diarrhea in China.