Fusion expression of mutated cecropin CMIV inE. coli

A cDNA coding mutated cecropin CMIV fromBombyx mori was synthesized according to its amino acid sequence usingE. coli biased codons. The gene was cloned into the fusion expression vector pEZZ318 and was expressed inE. coli HB101. The fusion protein produced was purified by affinity chromatography to yield 26 mg/L fusion product. The anti-bacterial activities of recombinant cecropin CMIV were recovered after cleavage by chemical method.

cDNA cloning, heterologous expression, and characterization of mouse CYP2G1, an olfactory-specific steroid hydroxylase

CYP2G1 is expressed specifically in the olfactory mucosa in rabbits and rats. In the present study, a full-length cDNA for mouse CYP2G1 was obtained using a PCR approach with RNA preparations from the olfactory mucosa of C57BL/6 mice. Sequence comparisons indicated that mouse CYP2G1 is highly homologous in deduced amino acid sequence to rabbit (82.4% identity) and rat CYP2G1 (94.9% identity). RNA blot and immunoblot analyses indicated that mouse CYP2G1 is expressed only in the olfactory mucosa. The coding region of the mouse CYP2G1 cDNA was cloned into a baculoviral expression vector for heterologous production of the enzyme in cultured insect cells. Heterologously expressed mouse CYP2G1 was active in a reconstituted system toward testosterone and progesterone, producing all the major metabolites detected in olfactory microsomal reactions, including 15 alpha-, 15 beta-, and 2 beta-hydroxytestosterone from testosterone and two unidentified metabolites from progesterone. Kinetic analysis indicated that mouse CYP2G1 has relatively high affinities toward the steroid substrates, with K(m) values in the micromolar range for both testosterone and progesterone. At a substrate concentration of 10 microM, microsomes of olfactory mucosa had much higher turnover numbers toward testosterone and progesterone than hepatic microsomes, consistent with the olfactory-specific expression of a high-affinity sex steroid hydroxylase. These findings will facilitate further molecular genetics studies on the biological function of CYP2G1 in a mouse model.

[Anterior segmental maxillary osteotomies (ASMO)]

Anterior segmental maxillary osteotomies (ASMO) were performed with both the Wassmund and downfracture methods in 15 patients and folloned-up regularly for 12 months The postoperative maxillary incisor edge point "Is" movements and complications were examined. The results indicated that the point "Is" movement was 1.66 +/- 0.77 mm postoperatively. No major complications occurred, The stability of anterior segmental maxillary osteotomies was found to be acceptable.

Transmission factors of schistosomiasis japonica in the mountainous regions with type of plateau canyon and plateau basin

OBJECTIVE

To provide the scientific basis for formulating the control strategies of schistosomiasis japonica in mountainous regions in China Schistosomiasis Control Programme.

METHODS

We selected Chuanxing Village in Sichuan Province and Zhonghe Village in Yunnan Province as the two pilot areas for an epidemiological investigation according to their geographical and topographical characteristics, i.e. plateau canyon and plateau basin, respectively. Concentrated-egg hatching method in nylon tissue bag and Kato-Katz technique were used for the survey on prevalence rate and intensity of infection of man and domestic animals. Questionnaires were applied to investigating the infection sources, community behavior and the socioeconomic status. Snail survey and detection of cercaria-infested water bodies were conducted using routine techniques.

RESULTS

The results showed that in the endemic areas with plateau canyon, the key infection source was cattle. The infection rate in women was higher than that in men. The pattern of water-pollution was wild feces and the pollution source was cattle feces. Snails and infectious snails were distributed over the rice fields and the resident was infected through production activities. In plateau basin, the key infection source was human beings. The infection rate in men was higher than that in women. The pattern of water pollution was fertilization. The pollution source was human feces. Snails and infectious snails were distributed over the canals and ditches and the resident was infected through production and daily activities.

CONCLUSIONS

Therefore, it was suggested that the mountainous endemic areas should be divided into two sub-types, i.e., plateau basins and plateau canyons. The different control strategies should be formulated in accordance with the environmental situations and socioeconomic factors in the two kinds of endemic areas.

Interleukin-13, in combination with anti-interleukin-12, increases graft prolongation after portal venous immunization with cultured allogeneic bone marrow-derived dendritic cells

Portal venous (pv) transfusion before transplant with large numbers (100 x 10(6)) of irradiated multiple minor histoincompatible spleen cells (B10.Br) augments allogeneic skin graft survival in C3H mice. We have shown in earlier studies that this is correlated with preferential activation for production of type 2 cytokines (interleukin [IL]-4 and IL-10) and decreased production of type 1 cytokines (IL-2 and interferon [IFN] gamma). We have also shown that recombinant (r)IL-12, in association with anti-IL-10 monoclonal antibody, can reverse in vivo the graft prolongation afforded by pv immunization and the altered cytokine production that follows. Adoptive transfer of inhibition of graft rejection is possible at early times after pv immunization, using plastic adherent cells obtained from the liver of treated mice. We show below that within 4 days of pv immunization, dendritic cells (NLDC-145+) isolated from the thymus, mesenteric lymph node (MLN), and.

Urokinase mutant with better fibrin-specificity

A 150-156 amino acids-deleted single-chain urokinase-type plasminogen activator (dscu-PA) and its recombinant wild-type counterpart (rscu-PA) were both expressed in Escherichia coli. After denaturation and renaturation in vitro, the expressed products were both purified to a single silver-stained band by means of IgG affinity chromatography. After activation by plasmin, similar enzymatic constants based on the hydrolysis of synthetic substrate S2444 by the two-chain molecular forms of dscu-PA and rscu-PA, or native tcu-PA were observed, suggesting that no impairment had been exerted on the catalytic active site of dtcu-PA by the 150-156 amino acids deletion. In both in vitro fibrin-clot and 125I-fibrin sepharose lysis tests, dtcu-PA showed a significantly higher fibrinolytic activity than rtcu-PA or rscu-PA. Hardly any effect on the concentration of fibrinogen in plasma was found in dtcu-PA. It was concluded that dtcu-PA had a higher fibrin specificity and that tcu-PA could be provided with better fibrin specificity by means of mutation.

The second space experiment of protein crystallization with domestic facilities

The second experiment of protein crystallization was performed on domestic re-entry satellite FSW-2 in 1994-07. The results are superior to the ones of the first mission in 1992: 9 of 10 different proteins were crystallized in space, and 70% of the total 48 samples yielded single crystals. Besides hen egg-white lysozyme which grew high-quality crystals on the first mission, an acidic phospholipase A2(aPLA2) from snake venom and hemoglobin from Anser Indicus produced good-quality crystals suitable for X-ray diffraction analyses. The positive effect of microgravity on protein crystal growth is verified again at this time.

[Clinical study on immunotherapy of ovarian cancer with tumor infiltrating lymphocytes]

OBJECTIVE

To investigate clinical usage of ovarian tumor infiltrating lymphocytes.

METHODS

Tumor infiltrating lymphocytes (TIL) were isolated by cold digestion method, specimens being taken from: (1) infiltrating node on tumor surface. (2) the tumor proper. (3) the ovarian tissue. A randomized, double-blind study on two groups on ovarian cancer, totally 25 patients was conducted. The first group was given TIL and chemotherapy and the second group was given chemotherapy only.

RESULT

The yields of infiltrating node on tumor surface were the highest (7.24 x 10(5)), in the tumor proper (2.49 x 10(5)), and in the ovarian tissue the lowest (2.07 x 10(5)). Growth of TIL in nodes on tumor surface increased 3,000 fold, in ovarian tissues and in tumor proper 2500 and 2000 times respectively. The most efficient killing activity was also presented in the infiltrating-nodes on tumor surface. CA125 decreased significantly, tumor regressed in two patients on follow-up by ultrasound, and ascites disappeared completely after one course of chemotherapy and TILs infusion.

CONCLUSION

The yields of TIL in infiltrating nodes on tumor surface and their efficiency in killing activity were higher than those in tumor proper and ovarian tissues, and the infiltrating nodes on tumor surface were considered the best sites for obtaining specimens.

The crystal structure of a high oxygen affinity species of haemoglobin (bar-headed goose haemoglobin in the oxy form)

We have determined the crystal structure of bar-headed goose haemoglobin in the oxy form to a resolution of 2.0 A. The R-factor of the model is 19.8%. The structure is similar to human HbA, but contacts between the subunits show slightly altered packing of the tetramer. Bar-headed goose blood shows a greatly elevated oxygen affinity compared to closely related species of geese. This is apparently due to a single proline to alanine mutation at the alpha 1 beta 1 interface which destabilises the T state of the protein. The beta chain N and C termini are well-localized, and together with other neighbouring basic groups they form a strongly positively charged groove at the entrance to the central cavity around the molecular dyad. The well-ordered conformation and the three-dimensional distribution of positive charges clearly indicate this area to be the inositol pentaphosphate binding site of bird haemoglobins.

Effectiveness of delta-aminolevulinic acid-induced protoporphyrin as a photosensitizer for photodynamic therapy in vivo

We examined the effectiveness of systemic administration of delta-aminolevulinic acid (delta-ALA) to induce endogenous protoporphyrin as a regimen for use in photodynamic therapy (PDT) of transplanted R3230AC rat mammary adenocarcinomas in vivo. Levels of porphyrins synthesized in various tissues after systemic administration of delta-ALA differed, with their accumulation in tumor tissue being dependent on both the dose and the time after delta-ALA administration. Tumor, liver, and intestine contained greater than 3.0 micrograms porphyrin/g tissue at 3 h after delta-ALA injection, whereas porphyrin levels in rat skin and muscle at that time were an order of magnitude lower. Analysis of tissue by HPLC revealed that the predominant porphyrin synthesized in tumors was protoporphyrin IX, whereas in liver, 18% of the total porphyrin detected was protoporphyrin IX, and in muscle, it was undetectable. Time-dependent studies of the uptake of 14C label from delta-ALA into the various tissues were not predictive of either the total amount of porphyrin or which porphyrin species would be present at 3 h after delta-ALA injection. Additionally, no simple relationship was apparent between the activities of certain selected enzymes involved in heme biosynthesis and the concentrations of porphyrins in the different tissues. High levels of tumor protoporphyrin IX were sustained by administration of two sequential doses of delta-ALA, at 3.0 and 1.5 h prior to irradiation. Using these treatment conditions, we inhibited R3230AC growth to an extent that was comparable to that obtained for Photofrin-induced PDT. High energy phosphate metabolism, measured by nuclear magnetic resonance spectroscopy in vivo, was dramatically impaired after delta-ALA-based PDT, with tumor ATP levels reduced to near zero by 4 h after irradiation. Our results demonstrated that delta-ALA-based PDT may be an alternative to current treatment protocols that use exogenously administered photosensitizers.

Expression of a biologically active human granulocyte-macrophage colony stimulating factor fusion protein in Escherichia coli

A gene encoding human granulocyte-macrophage colony stimulating factor(GM-CSF), was cloned into plasmid pEZZ318 and fused to a DNA segment coding for the signal peptide of staphylococcal protein A and a synthetic gene coding for a protein with ability to bind immunoglobulin G(IgG). The fusion protein was expressed in Escherichia coli and biologically actively secreted into the growth medium. Approximately all of the total activity was secreted into the culture medium, where levels of activity approached 1.96 x 10(8) units/liter. Purification of the fusion protein was performed in a single step by affinity chromatography with immobilized IgG to a specific activity of 1.2 x 10(8) units/mg.

Expression and purification of a truncated macrophage colony stimulating factor in Kluyveromyces lactis

A truncated human macrophage colony stimulating factor (M-CSF) cDNA encoding amino acid residues from 3 to 149 of the native M-CSF was obtained by using polymerase chain reaction. When inserted into plasmid pCXJ1 and psPHO5 and introduced into Kluyveromyces lactis, it directs the the secretory expression of the biologically active dimeric form of M-CSF. Through a four-step purification protocol, i.e. ammonium sulfate salting out, DEAE-cellulose column chromatography, hydrophobic chromatography on phenyl-sepharose and Mono Q fast protein liquid chromatography, the recombinant truncated M-CSF was purified to homogenerity and show its apparent molecular mass at 21KDa on reduced SDS-PAGE, with a specific activity of 1.21 x 10(7) units/mg protein.

Expression of a fibrinolytically active human pro-urokinase fusion protein in Escherichia coli

The gene encoding human pro-urokinase(pro-UK) was cloned into plasmid pEZZ318 and fused to the gene coding for the signal peptide of staphylococcal protein A and IgG bindinging domain. The fusion protein which was synthesized under the control of T7 promoter in Escherichia coli and secreted into the growth medium, was found to be fibrinolytically active. Approximately 60% of the total activity was secreted into the culture medium, where levels of activity approached 150,000 I.U./liter and about 40% of the total activity remained in the cell lysate with levels of activity around 100,000 I.U./liter. The fusion protein was purified in a single step by IgG affinity chromatography. These results demonstrate that human pro-UK can be synthesized and secreted by E. coli as a fibrinolytically active fusion protein.

[Exploration on the association between the pattern of HBV markers and infection of HCV among population]

Sera from 193 cases with positive HBV markers in April 1993 were detected for infection of HCV to explore the association between the pattern of HBV markers and the infection of HCV among population. The result showed that 14 patterns were found: the pattern of positive HBsAg, HBeAb, HBcAb (43.01%) and the pattern of positive HBsAg, HBeAg, HBcAb (30.57%) were more often seen. The percentage of HCV infection among cases infected with HBV was 11.39%. The difference of the positive rate of anti-HCV among various patterns of HBV markers was significant (chi 2 = 24.48, P = 2.062 x 10(-5).

Altered alpha 1-adrenoceptor density and alpha 1A/alpha 1B ratio in rat hearts after propranolol treatment

After rats were treated with propranolol (50 mg.kg-1, bid, ip) for 7 d, the density of alpha 1-adrenoceptors in the rat myocardial cell membranes increased from 137 +/- 25 to 178 +/- 30 fmol/mg protein determined by receptor radioligand assay. Whereas the KD value was not significantly changed, the relative proportion of alpha 1A-adrenoceptor subtype increased from 19 +/- 6 to 31 +/- 8%. The affinities of two subtypes to 5-methylurapidil were not obviously changed after propranolol treatment. It was suggested that alpha 1A-subtype was more important in alpha 1-receptor mediated alterations after beta-adrenoceptor blockade.

High-efficiency transfection of primary human keratinocytes with positively charged lipopolyamine:DNA complexes

The ability to introduce DNA into mammalian cells has provided a powerful means to examine the regulation of gene expression and the function of gene products. However, the most commonly used techniques for DNA transfection are not always suitable for primary cells. Primary human keratinocytes are particularly stringent in their growth requirements and are also very refractory to transfection, rendering transient gene expression studies difficult. We have investigated the ability of several polycationic lipids to promote DNA uptake into human epidermal keratinocytes, as monitored with the bacterial beta-galactosidase reporter gene. We report that the cationic lipopolyamine dipalmitoyl phosphatidylethanolamine spermine as well as another procedure using Polybrene can achieve a 20% to 30% transfection efficiency, superior to any other agent tested on these cells. Gene transfer was accomplished by a 3-h exposure of monolayer cells to DNA complexes formed with either reagent by simple mixing in a serum-free medium, followed by a brief osmotic shock with glycerol. Neither DNA carrier showed any toxicity at the effective concentrations nor interfered with cell attachment, growth or differentiation. The use of a fully biodegradable lipopolyamine as DNA carrier should make it possible to extend this transfection method to gene transfer for in vivo therapeutic applications.

Run-down of calcium current is related to intracellular sodium

Run-down of Ca2+ current was studied in isolated guinea pig ventricular cells and it was found to be attenuated by intracellular sodium. Calcium currents were recorded after activation of Na+ channels by a step pulse. The "run-down" in 30 min was significantly reduced compared with control cells. When NaCl (0.1-10 mM) diffused from the micropipette into the cells, run-down of Ca2+ current was also significantly attenuated. However, the resulted increase of intracellular Na+ did not affect voltage dependent activation of Ca2+ current, but the duration of the action potential was shortened slightly.

Enhancement of expression of human granulocyte-macrophage colony stimulating factor by argU gene product in Escherichia coli

Human granulocyte-macrophage colony stimulating factor (hGM-CSF) was cloned into expression vector pIN III-ompA1 and expressed in Escherichia coli JA221. When supplementation with a minor tRNA(AGA/AGG)Arg encoded by the E. coli argU gene, the expression level of hGM-CSF was raised about 3-4-fold, although there is only one rare AGG codon in hGM-CSF cDNA gene.

Blocking effect of rhynchophylline on calcium channels in isolated rat ventricular myocytes

The effect of rhynchophylline (Rhy) on L-type Ca2+ channel current was studied in rat ventricular myocytes using patch-clamp whole-cell recording technique. When the holding potential was -40 mV, cells were depolarized to 0 mV for 250 ms at frequency of 0.5 Hz, Rhy 10 and 50 mumol.L-1 reduced verapamil-sensitive Ca2+ inward current by 60% and 80%, respectively, without affecting the voltage-dependency of the maximal activation of Ca2+ current. This indicated that the effect of Rhy on the activation of Ca2+ channel was voltage-independent. The effect of Rhy on Ca2+ current reached the maximum at 10 min and was partially recovered by washout of Rhy. A pD2 value of 5.91 and Hill coefficient of 1.1 were obtained from the concentration-response curve.

Alpha 1A- and alpha 1B-adrenoceptor-mediated positive chronotropic effects on isolated rat atrium

The positive chronotropic effect of alpha 1-adrenoceptor subtypes was studied on the isolated right atrium of adult male Wistar rats. In the presence of beta-blocker propranolol, chloroethylclonidine (Chl) (an irreversible alpha 1B inactivator) reduced the positive chronotropic effect of phenylephrine (Phe). When the basal rate was lowered by cholinergic stimulation. Chl showed less effect on the increase of spontaneous beat rate. H-7, a protein kinase C (PKC) inhibitor, lowered the chronotropic effect to Phe under physiological condition, but did not affect the Phe-induced positive chronotropic effect when basal rate was lessened by carbachol. These suggested that the chronotropic effect was mainly mediated by alpha 1B receptors, and partially related to the activation of PKC by second messengers under physiological conditions. The compensatory effect of the alpha 1-adrenoceptors was mainly mediated by alpha 1A receptors, which is scarcely involved in the activation of PKC.