[Management of deep facial burn with early postburn debridement and delayed skin grafting]

OBJECTIVE

To explore optimal methods of the management of deep facial burn, so as to prevent the development of facial scar hypertrophy and deformity.

METHODS

Partial tangential excision, delayed skin grafting, early relief of the eyelid eschar and immediate skin grafting were carried out in burn patients with deep facial burn during the early postburn stage.

RESULTS

The wounds in 12 cases had healed completely within 3 postburn weeks(PBW). Scar hypertrophy and facial deformity were not observed during the follow-up. All the patients could express natural facial expressions.

CONCLUSION

Facial deep burn wound could be managed as soon as possible with early partial tangential excision and delayed skin grafting. As a result, facial scar hypertrophy and deformity could be avoided.

The transmembrane domain of the Alzheimer's beta-secretase (BACE1) determines its late Golgi localization and access to beta -amyloid precursor protein (APP) substrate

Release of Abeta peptides from beta-amyloid precursor protein (APP) requires sequential cleavage by two endopeptidases, beta- and gamma-secretases. beta-Secretase was recently identified as a novel membrane-bound aspartyl protease, named BACE1, Asp2, or memapsin 2. Employing confocal microscopy and subcellular fractionation, we have found that BACE1 is largely situated in the distal Golgi membrane with a minor presence in the endoplasmic reticulum, endosomes, and plasma membrane in human neuroblastoma SHEP cells and in mouse Neuro-2a cell lines expressing either endogenous mouse BACE1 or additional exogenous human BACE1. The major cellular beta-secretase activity is located in the late Golgi apparatus, consistent with its cellular localization. Furthermore, we demonstrate that the single transmembrane domain of BACE1 alone determines the retention of BACE1 to the Golgi compartments, through examination of recombinant proteins of various BACE1 fragments fused to a reporter green fluorescence protein. In addition, we show that the transmembrane domain of BACE1 is required for the access of BACE1 enzymatic activity to the cellular APP substrate and hence for the optimal generation of the C-terminal fragment of APP (CTF99). The results suggest a molecular and cell biological mechanism for the regulation of beta-secretase activity in vivo.

BACE2 functions as an alternative alpha-secretase in cells

BACE1 and BACE2 define a new subfamily of membrane-anchored aspartyl proteases. Both endoproteases share similar structural organization including a prodomain, a catalytic domain formed via DTG and DSG active site motifs, a single transmembrane domain, and a short C-terminal tail. BACE1 has been identified as the Alzheimer's beta-secretase, whereas BACE2 was mapped to the Down's critical region of human chromosome 21. Herein we show that purified BACE2 can be autoactivated in vitro. Purified BACE2 cleaves human amyloid precursor protein (APP) sequences at the beta-secretase site, and near the alpha-secretase site, mainly at A beta-Phe(20)--Ala(21) and also at A beta-Phe(19)--Phe(20). Alternatively, in cells BACE2 has a limited effect on the beta-secretase site but efficiently cleaves the sequences near the alpha-secretase site. The in vitro specificity of APP processing by BACE2 is distinct from that observed in cells. BACE2 localizes in the endoplasmic reticulum, Golgi, trans-Golgi network, endosomes, and plasma membrane, and its cellular localization patterns depend on the presence of its transmembrane domain. BACE2 chimeras that increase localization of BACE2 in the trans-Golgi network do not change its APP processing patterns. Thus, BACE2 can be distinguished from BACE1 on the basis of autoprocessing of the prosegment, APP processing specificity, and subcellular localization patterns.

Astilbin selectively facilitates the apoptosis of interleukin-2-dependent phytohemagglutinin-activated Jurkat cells

The present study examined the relationship between the activation of T cells and the apoptosis-facilitating effect of astilbin on them. By the stimulation of PHA, a remarkable IL-2 production was detected in the supernatant of Jurkat cells after 120 h among 72--144 h incubation. This kinetics was quite in accordance with that of astilbin-induced apoptosis of Jurkat cells, where 1 h-exposure of the PHA-activated cells to astilbin caused a significantly increased apoptosis in a dose-dependent manner. To the Jurkat cells that had been cultivated for 72--144 h without PHA, however, astilbin did not show any facilitation of the cell apoptosis. Pre-treatment by cyclosporine A simultaneously with PHA dose-dependently lowered the IL-2 production and susceptibility of the cells to astilbin, while the treatment after 120 h of PHA-activation did not. The exogenous IL-2 treatment after 72 h of PHA-activation significantly and dose-dependently raised the susceptibility of the Jurkat cells to astilbin. These results indicated the dependency of the apoptosis-facilitating effect of astilbin on appropriate status of activated T lymphocytes with a relation to IL-2 production. This characteristic of astilbin may be of great significance for the treatment of a variety of immunologically related diseases.

Fate of selenium in coal combustion: volatilization and speciation in the flue gas

In light of Title I of the Clean Air Act Amendments of 1990, selenium will most probably be considered for regulation in the electric power industry. This has generated interest for removing this element from fossil-fired flue gas. This study deals with coal combustion: selenium volatilization and its speciation in the cooled flue gas were investigated to better understand its chemical behavior to validate the thermodynamic approach to such complex systems and to begin developing emission control strategies. Se volatility is influenced by several factors such as temperature, residence time, fuel type, particle size, and Se speciation of the fuels, as well as the forms of the Se inthe spiked coal/coke. Spiked coke and coal samples were burned in a thermobalance, and atomic Se and its dioxide were identified in the cooled combustion flue gas by X-ray photoelectron spectroscopy (XPS). A thermodynamic calculation was applied to a complex system including 54 elements and 3,200 species that describes the coal combustion. Several theoretical predictions concerning Se behavior, such as its speciation in flue gas, agreed well with experiments, which supports using thermodynamics for predicting trace element chemistry in combustion systems.

Sodium-ascorbate cotransport controls intracellular ascorbate concentration in primary astrocyte cultures expressing the SVCT2 transporter

Expression of the Na(+)-ascorbate cotransporter, SVCT2, was detected in rat brain and in primary cultures of cerebral astrocytes by Northern blot analysis. SVCT2 expression in cultured astrocytes increased in response to the cyclic AMP analog, dibutyryl cyclic AMP. A mathematical model of ascorbic acid transport was developed to evaluate the hypothesis that Na(+)-ascorbate cotransport across the plasma membrane regulates the steady state intracellular concentration of ascorbic acid in these cells. The outcomes predicted by this model were compared to experimental observations obtained with primary cultures of rat cerebral astrocytes exposed to normal and pathologic conditions. Both cotransport activity and intracellular ascorbic acid concentration increased in astrocytes activated by dibutyryl cyclic AMP. Conversely transport activity and ascorbic acid concentration were decreased by hyposmotic cell swelling, low extracellular Na(+) concentration, and depolarizing levels of extracellular K(+). In cells incubated for up to 3 h in medium having an ascorbic acid concentration typical of brain extracellular fluid, the changes in intracellular ascorbic acid concentration actually measured were not significantly different from those predicted by modeling changes in Na(+)-ascorbate cotransport activity. Thus, it was not necessary to specify alterations in vitamin C metabolism or efflux pathways in order to predict the steady state intracellular ascorbic acid concentration. These results establish that SVCT2 regulates intracellular ascorbic acid concentration in primary astrocyte cultures. They further indicate that the intracellular-to-extracellular ratio of ascorbic acid concentration at steady state depends on the electrochemical gradients of Na(+) and ascorbate across the plasma membrane.

Influence of process parameters on the protein stability encapsulated in poly-DL-lactide-poly(ethylene glycol) microspheres

Glucose oxidase (GOD) has been encapsulated as a model protein within poly-DL-lactide-poly(ethylene glycol) (PELA) microspheres to evaluate the activity retention during microencapsulation process. This paper was aimed to investigate the effect of process parameters, such as the preparation method, the used matrix polymer with different compositions, the solvent system and the addition of stabilizer on the structural integrity and activity retention of encapsulated protein. The stability of the protein released during in vitro assay was also assessed. The obtained results showed that the solvent extraction/evaporation method based on the formation of double emulsion w(1)/o/w(2) benefited the activity retention compared with the phase separation method based on the formation of w/o(1)/o(2). And in the emulsion-evaporation system most of the protein activity was lost during the first emulsification procedure to form primary emulsion w(1)/o (ca. 28%) and the second emulsification procedure to form the double emulsion w(1)/o/w(2) (ca. 20%), in contrast to other processes occurring during microspheres preparation. The matrix polymer and the solvent system in the oil phase had an impressive impact on the activity retention, while the addition of gelatin in the internal aqueous phase resulted in no major reduction of activity loss. GOD release from PELA microspheres exhibited a triphasic profile, that is, the initial burst release during the first day, the gradual release over about 1 month, and then the second burst release. The encapsulation of GOD in PELA microspheres was effective in reducing its specific activity loss. Sixty-seven per cent of the initial specific activity retention was detected for the released GOD from microspheres formulation during 1 week of incubation, but nearly all the activity was lost for GOD in solution incubated under the same condition. SDS-PAGE results showed that, although the activity loss was detected, no rough changes of molecular weight of GOD was observed during encapsulation procedure and the initial days of incubation into the in vitro release medium.

Body distribution of poly-DL-lactide-poly(ethylene glycol) microspheres with entrapped leptospira interrogans antigens following intravenous and oral administration to guinea-pigs

Poly-DL-lactide-poly(ethylene glycol) (PELA) microspheres with entrapped antigens were administered intravenously and orally into guinea-pigs to quantitatively determine the in-vivo distribution and release profiles. PELA microspheres containing 125I-labelled outer-membrane protein Leptospira interrogans antigens (125I-OMP) were prepared by double-emulsion solvent extraction procedure, and characterized with respect to size, morphology and in-vitro release profiles. The fractured sections of liver and spleen were inspected by scanning electron microscopy, which indicated that microspheres had successfully been entrapped within the above tissues after intravenous injection and oral administration. At predetermined intervals, the blood and such tissues as the liver, spleen, kidney, thyroid, small intestine and mesentery were collected, and the radioactivity was measured by gamma scintillation counting. Following intravenous administration, 56.7% of administered microspheres were accumulated in immunization-related tissues, and 40.1% of microspheres were located in the liver and spleen. However, there was limited uptake efficiency (8.33%) following oral administration, and 49.5% of the absorbed microspheres were located in the intestinal mucosa. Compared with in-vitro release, the in-vivo release profiles of 125I-OMP from PELA microspheres, determined from the decreasing radioactivity in the above tissues, were much faster and the burst effect was higher. Antigen-loaded PELA microspheres were efficiently entrapped within immunization-related tissues after intravenous administration, but orally administered PELA microspheres showed limited uptake efficiency. Further investigation is needed to improve intestinal absorption.

Menopausal symptoms: experience of Chinese women

OBJECTIVES

To investigate the prevalence of symptoms in middle-aged Chinese rural and city women of different occupations; and to explore the relationship between symptoms, hormone levels and other factors.

METHODS

This cross-sectional study included 806 women aged 41-60 years, selected by multistage cluster sampling and a structured interview questionnaire. The response rate was 95%. The sample compromised 402 professional urban women and 404 women farmers living in rural areas. Some 209 women were randomly selected from the two groups for hormonal assay and bone mineral density screening.

RESULTS

The professional group was more symptomatic than the farming group (p < 0.01). The presence of symptoms was significantly related to an increasing level of education. There were no significant differences between occupational groups in levels of estradiol follicle stimulating hormone (FSH) and luteinizing hormone (LH). Estradiol level and bone mineral density were decreased and FSH and LH increased in the postmenopausal group (p < 0.05) compared with the other menopausal groups. Hot flushes were the only symptom to be significantly associated with hormone levels (estradiol and LH). The occurrence of symptoms was significantly related to indications of bone and joint disease, heart disease, primary dysmenorrhea, decline in sexual interest, irregular menses and feelings of becoming older, sad and lost. These factors were all reported more often by the professional women than by the farmers.

CONCLUSION

Symptom experience in mid-life Chinese women is related to both biological and psychosocial factors.

AIT-082, a cognitive enhancer, is transported into brain by a nonsaturable influx mechanism and out of brain by a saturable efflux mechanism

A fundamental feature of any drug designed to treat a disease of the central nervous system is the ability to cross the blood-brain barrier. Passage across the blood-brain barrier of AIT-082, a cognitive enhancer, was investigated in mice. [(14)C]AIT-082 crossed the blood-brain barrier in young male Swiss-Webster mice with a mean influx constant (K(i)) of 0.6 +/- 0.2 microl g(-1) min(-1). Furthermore, [(14)C]AIT-082 was transported into brain of both young and old male C57BL/6 mice with a K(i) of 0.35 +/- 0.06 and 0.33 +/- 0.02 microl g(-1) min(-1), respectively. There was no significant effect of age or strain on the movement of [(14)C]AIT-082 across the blood-brain barrier in mice. When 110- or 650-fold excess unlabeled AIT-082 was included in the injection solution, the K(i) was not significantly changed in either Swiss-Webster or C57BL/6 mice. This indicated that [(14)C]AIT-082 crossed the blood-brain barrier by a nonsaturable mechanism. The passage of AIT-082 into brain extracellular fluid was confirmed with capillary depletion and microdialysis. The efflux of [(14)C]AIT-082 from brain also was examined. After i.c.v. injection, [(14)C]AIT-082 levels in brain decreased over time with a t(1/2) of 20.0 +/- 1.0 min. Excess unlabeled AIT-082 (600-fold) increased the t(1/2) to 35.5 +/- 3.6 min. Together, these data indicate that AIT-082 moves into brain via a nonsaturable mechanism and is actively transported out of brain.

Membrane-anchored aspartyl protease with Alzheimer's disease beta-secretase activity

Mutations in the gene encoding the amyloid protein precursor (APP) cause autosomal dominant Alzheimer's disease. Cleavage of APP by unidentified proteases, referred to as beta- and gamma-secretases, generates the amyloid beta-peptide, the main component of the amyloid plaques found in Alzheimer's disease patients. The disease-causing mutations flank the protease cleavage sites in APP and facilitate its cleavage. Here we identify a new membrane-bound aspartyl protease (Asp2) with beta-secretase activity. The Asp2 gene is expressed widely in brain and other tissues. Decreasing the expression of Asp2 in cells reduces amyloid beta-peptide production and blocks the accumulation of the carboxy-terminal APP fragment that is created by beta-secretase cleavage. Solubilized Asp2 protein cleaves a synthetic APP peptide substrate at the beta-secretase site, and the rate of cleavage is increased tenfold by a mutation associated with early-onset Alzheimer's disease in Sweden. Thus, Asp2 is a new protein target for drugs that are designed to block the production of amyloid beta-peptide peptide and the consequent formation of amyloid plaque in Alzheimer's disease.

[Influence of compensatory hepatocyte proliferation on the carcinogenesis of N-nitrosodimethylamine]

OBJECTIVE

To study the influence of compensatory hepatocyte proliferation on the N-nitrosodimethylamine (NDMA) carcinogenesis in rats.

METHODS

NDMA was given to animals of the experimental group 24 hours after partial hepatectomy, and the control group was only treated with NDMA. Expression of gamma-glutamyltransferase (GGT), glutathione S-transferase placental form (GSTP), proliferating cell nuclear antigen (PCNA), insulin-like growth factor-II (IGF-II) and oncogenes was detected.

RESULTS

The numbers and areas of GGT- and GSTP-foci in the experimental group were significantly increased in comparing with the control groups. The expression of GSTP was higher than that of GGT. The total tumor incidence of the experimental group was higher than that of the control by the end of the 56th week. Up to week 71, the incidences of liver and other tumors were higher respectively in the experimental group. The amount of PCNA positive cells were corresponding with proliferative condition of the hepatic lesions. The expression of IGF-II, c-myc and H-ras mRNA increased in the altered hepatocyte foci and nodules, but markedly decreased in hepatocellular carcinoma and adenoma. No c-jun mRNA expression was detected in all the normal and abnormal tissues of liver.

CONCLUSIONS

The results suggest that compensatory hepatocyte proliferation enhances the carcinogenesis induced by multiple doses of NDMA, and the over expression of IGF-II, c-myc, H-ras may play a synergetic role in NDMA-induced hepatocarcinogenesis.

[A study on processing of the root of Astragalus membranaceus Bge. by HPLC]

The paper presents a study on the drug-processing of the root of Astragalus membranaceus. A HPLC method for the determination of astragaloside IV in its processed products has been established. The recovery is 96.1% and the RSD is 2.15%.

[The relationship between severe burn injury and systemic inflammatory response syndrome]

OBJECTIVE

To study course of systemic inflammatory response syndrome (SIRS).

METHODS

The relationship was observed between SIRS and the effect of burn injury on cellular and humoral immunity between survivors. Nonsurvivors were also compared. The gastric mucosal pHi was measured.

RESULTS

The SIRS initiated 22 hours after burn injury and peaked 3 days to 7 days postburn. Compared to the survivors significan increase of content of TNF and decrease of content of G-CSF were detected in the nonsurvivors serum. Obvious immunosuppression could be found. In patients with SIRS accompanied with infection or organ failure, marked increase of mortality was seen. The value of pHi was very low.

CONCLUSION

Severe burn injury can lead to the release of massive inflammatory mediators. The second insult such as infection can further amplify the process leading to a vicious cycle of inflammation which cause tissue damage and immunosuppression. To prevent MODS, early diagnosis and treatment including organ supply, use of antibacterial agents, oxygen supply and immunity therapy were necesary.

[Immunoblots of hydrophobic OmpL39 of Leptospiral interrogans with immunoprotective Mb E4B7G5]

The immunoprotective Mb E4B7G5 against outer membrane antigens from L. interrogans serovar Lai strain 017 were produced and used in immunoblots of the OMP of six strains of L. interrogans (017, 601, 603, 609, 620 and 245). The OMP from the six strains, which partitioned into the hydrophobic detergent phase, contained four-seven major proteins bands of 66 kd-16 kd. It was found that Mb E4B7G5 recognized only specifically the 39 kd antigenic band of strain 017, 601, 603 and 609, and did not recognize apparently any bands of strains 620 and 245. The findings suggest that Mb E4B7G5 be valuable for separating protective antigen of OMP and studying genetic vaccines.

[Levels of serum G-CSF and supplement of GM-CSF in rats sustaining delayed resuscitation after major burn]

Delayed fluid resuscitation of burn shock may lead to infection in early period following major burn injury, resulting in multiple organ failure with high mortality. The change in colony stimulation factors (CSFs) may play a role in developing infection. We assessed the levels of serum granulocyte colony stimulation factor (G-CSF), tumor necrosis factor-alpha (TNF-alpha), phagocytosis of neutrophil and counts of peripheral blood cells of rats with 30% TBSA full thickness burn having either immediate or delayed fluid replacement. We also evaluated the efficacy of granulocyte-macrophage colony-stimulating factor (GM-CSF) in improving survival of rats following burn injury with a superimposed burn wound infection.

THE RESULTS

1. A delayed rise in serum G-CSF was found in delayed resuscitation group, and the levels of serum G-CSF and phagocytosis of neutrophil were lower compared with immediate resuscitation group. 2. Nonsurvival group had lower levels of serum G-CSF and higher content of TNF-alpha compared with survival. 3. Supplement of GM-CSF could significantly improve animal survival with burn wound infection following severe burn shock.

CONCLUSION

Decrease in G-CSF production plays a role in developing fatal wound infection after severe burn shock; supplement of GM-CSF is beneficial in improving survival.

[GS-MS analysis of essential oils from five species of Asarum]

This paper reports the result of GS-MS analysis of the essential oils from five species of Asarum, namely, A. heterotropoides var. mandshuricum (cultivated), A. sieboldii (cultivated), A. caudigerellum (from Sichuan), A. sieboldii(from Shandong) and A. sieboldii(wild). Ninety-two constituents were detected, of which 73 compounds were identified.

[Construction of genomic library of L. interrogans serovar lai using lambda gt11 as the vector and a study of recombiant plasmid pDL121]

A genomic library of L. interrogans serovar lai strain 017 has been constructed using lambda gt11 as the vector. DNA was partially digested by two blunt-end restriction enzymes, then methylated with EcoR I methylase; after EcoR I linker was added to the DNA, the linker-ended DNA was ligated to the dephosphorylated EcoR I digested lambda gt11 arms. The recombined DNA was packaged in vitro, and used to transduct E. coli Y1090 for amplification. There were 2.1 x 10(6) recombinant bacteriophages as recognized by their ability to form white plaques plated on Lac host in the presence of both IPTG and X-Ga1. A positive clone, designated lambda DL12, was screened with a rabbit anti-serum against L. interrogans serovar lai from the genomic library. The DNA from lambda DL12 was subcloned into plasmid pUC18. A recombinant (designated as pDL121) was obtained. SDS-PAGE analysis indicated that a 23 kd was expressed in E. coli JM 103 harboring pDL121. Western blotting analysis showed that a specific protein band molecular weight of 23 kd could be recognized by the rabbit antiserum against L. interrogans serovar lai strain 017.

[Studies on bone density in healthy girls during their period of growth spurt]

Bone mass in 69 healthy girls in their period of growth spurt was measured twice, with an interval of one year, by dual energy X-ray bone densitometer to study the relationship between changes in bone density and the speed of height growth, development of secondary sex characteristics and nutritional status. Results showed that bone density in the different sites in the period of growth spurt increased significantly with their age, but with difference in the magnitude of its increase and in the time. Their nutritional status (overweight or underweight) correlated closely with sex development and increase in bone density. It suggests that it is necessary to strengthen nutrient intake during their puberty for preventing from osteoporosis. In addition, early puberty is an important period for the increase in female bone density, as a result of comparison of bone mass between prepuberty girls and young women. The results in this study can provide reference for further studies on bone mass in girls during their puberty.

[Research on the recombinant plasmid pDJH2 of L. interrogans serovar lai: sequencing and alignment with other known bacterial Omp sequence]

The Leptospira whole cell vaccine (LWCV) currently used in China is safe and effective, out the immunity following vaccination with two doses of the fluid medium vaccine is of low order. The duration of immunity conferred by this vaccine is rather short, six months or at most one year. Therefore, it is necessary to develop new generation vaccines against Leptospirosis for the developing world. In this paper we report the sequencing of the insert fragment of pDJH2 from genomic DNA of L. interrogans sevovar lai strain 017 and its alignment with other bacterial omp sequences. A genomic library of Leptospira interrogaans serovar lai strain 017 was constructed with the plasmid vector pUC18. A recombinant plasmid designated pJDH2 was screened from the genomic library. Inserted fragment of pDH2 is 1.9 kb by gel electrophoresis. Immunization/protection was studied in BALB/c mice model. The results showed highly significant difference between pDJH2 and pUC18 (control). Inserted fragment of pDJH2 DNA sequencing was performed by Dr Yan Zhengxin (Max-Planck-Institut for Biology. Tubingen, Germany). Insert fragment was cloned into pBluescript II KS-(stratagene) and sequenced by using AB1 (Applied Bio Systems, Model 373A). Two open reading frames of 565 and 662 nucleotides were identified. There were identifiable initiation codons, terminators, Shine-Dalgano ribosome combining site, Pribnow boxes and Sextama boxes within the 2 sequenced regions. Nucleotide sequences were analysed using Gene Work, a suit of computer program developed by Department of Biochemistry St. Jude Children's Research Hospital Memphis. U.S.A. The results of formatted alignment showed the predicted nucleotide sequence of ORF1 of the serovar lai had significant similarity with ORF2 (49.36%). L. kirschneri ompL1 (49.26%), Borrelia burgdoferi omp (48.97%), Treponema phagedenis omp (47.3%); Salmonella typhimurium ompC(46.87%), Yersinia enterocolitica ompH (46.7%), Leptospira borgpeterseni pfap (46.3%), and Serratia marcescens omp (43.3%). The close relationship of the pDJH2 ORF1 and ORF2 nucleotide sequences from Leptospira kirschneri ompL 1 is apparent. Whether the recombinant pDJH2 will prove useful for vaccine development remains to be tested.

Unique signal transduction of Eyk: constitutive stimulation of the JAK-STAT pathway by an oncogenic receptor-type tyrosine kinase

The proto-oncogene c-eyk, the cellular counterpart of a transforming oncogene, v-eyk, encodes a receptor protein tyrosine kinase with a distinctive extracellular region. We now demonstrate that c-Eyk can be constitutively activated through dimerization, and that the active Eyk displays a unique signaling pattern. When the kinase domain of c-Eyk was fused to the extracellular and transmembrane domains of CD8, the resulting chimera showed elevated kinase activity and caused cellular transformation. We found that the activated Eyk kinases, both v- and c-Eyk, constitutively stimulate the JAK-STAT pathway, while exerting little effect on other signaling routes such as the Ras-MAP kinase and the JNK pathways. The activated Eyk kinases specifically stimulate tyrosine phosphorylation of STAT1, STAT3 and JAK1. These downstream molecules also co-immunoprecipitate with the constitutively dimerized form of Eyk. The Eyk kinase activity is required for STAT1 stimulation. We found that the activation of STAT1 but not STAT3 correlates well with cellular transformation. In constitutively stimulating the JAK-STAT pathway, particularly STAT1, Eyk is unique in its downstream signaling and may be dependent on this pathway for cellular transformation.

A JAK-STAT pathway regulates wing vein formation in Drosophila

We present evidence that the JAK-STAT signal transduction pathway regulates multiple developmental processes in Drosophila. We screened for second-site mutations that suppress the phenotype of the hyperactive hopTum-1 Jak kinase, and recovered a mutation that meiotically maps to the known chromosomal position of D-Stat, a Drosophila stat gene. This hypomorphic mutation, termed statHJ contains a nucleotide substitution in the first D-Stat intron, resulting in a reduction in the number of correctly processed transcripts. Further, the abnormally processed mRNA encodes a truncated protein that has a dominant negative effect on transcriptional activation by the wild-type cDNA in cell culture. statHJ mutants exhibit patterning defects that include the formation of ectopic wing veins, similar to those seen in mutants of the epidermal growth factor/receptor pathway. Abnormalities in embryonic and adult segmentation and in tracheal development were also observed. The hopTum-1 and statHJ mutations can partially compensate for each other genetically, and Hop overexpression can increase D-Stat transcriptional activity in vitro, indicating that the gene products interact in a common regulatory pathway.

[Basic research and clinical applications of the human hair suture]

An atraumatic suture was manufactured from human hair, which has been tested and used in 817 clinical cases with satisfactory results. The authors found that the suture has the following characteristics: smooth, thin, strong and elastic, structurally steady, histocompatible, atoxic, aseptic, atraumatic, with endurance of more than one thousand times of bending. It does not swell in water or blood nor it causes reaction after being buried in tissue for 150 days. It definitely has an advantage over the silk and nylon. The rich resources of hair favor its wide applications.

Identification of a Stat gene that functions in Drosophila development

A Drosophila Stat gene (D-Stat) with a zygotic segmental expression pattern was identified. This protein becomes phosphorylated on Tyr-704 when coexpressed in Schneider cells with a Drosophila janus kinase (JAK), Hopscotch (HOP). The phosphorylated protein binds specifically to the consensus sequence TTCCCGGAA. Suppressor mutations of hopTum-I, a dominant hyperactive allele of hop whose phenotype is hematocyte overproduction and tumor formation, were selected. One of these mutants, statHJ, mapped to the same chromosomal region (92E) as does D-Stat, had an incompletely penetrant pair rule phenotype, and exhibited aberrant expression of the pair rule gene even skipped (eve) at the cellular blastoderm stage. Two D-STAT-binding sites were identified within the eve stripe 3 enhancer region. Mutations in either of the STAT-binding sites greatly decreased the stripe 3 expression in transgenic flies. Clearly, the JAK-STAT pathway is connected to Drosophila early development.

[Early enteral feeding and supplement of glutamine prevent occurrence of stress ulcer following severe thermal injury]

Gastroscopic and gastric juice analysis studies were carried out on 12 patients with total body surface area over 30 percent who received early enteral feeding, supplemented with glutamine. The results indicated that early feeding was safe in major burn patients. All patients were found to have ASML on postburn days 1 to 2. Stress ulcer was not found in patients after several excision operations, and about 86 percent of ASML disappeared within about 2 weeks.

CONCLUSION

early feeding and supplement of glutamine can prevent the complication of stress ulcer following severe thermal injury.

Human protein synthesis initiation factor eIF-4 gamma is encoded by a single gene (EIF4G) that maps to chromosome 3q27-qter

Messenger RNA binding to the ribosome, the rate-limiting step in eukaryotic protein synthesis, is catalyzed by the eIF-4 group of initiation factors. These factors collectively bind to the m7GTP-containing cap of mRNA and unwind mRNA secondary structure at the expense of ATP. One member of the group, eIF-4 gamma, is the target for proteolytic cleavage during picornavirus infection, an event that is thought to be responsible for the inhibition of host cellular mRNA translation. Human eIF-4 gamma migrates as a cluster of polypeptides in the range of 200-220 kDa during SDS-PAGE, raising the possibility that it is a family of proteins encoded by separate genes. In this study, we present genomic Southern blotting results which indicate that there is only a single gene, here designated EIF4G. Furthermore, we have employed a PCR approach to map EIF4G to chromosome 3q27-qter.

The genomic structure of the STAT genes: multiple exons in coincident sites in Stat1 and Stat2

The genomic structure of Stat2 has been determined and compared with a large portion of the Stat1 gene. There are 24 exons in the Stat2 gene and a matching number in very similar positions in the Stat1 gene. Thus a very complicated genomic structure was presumably duplicated and has been closely maintained throughout evolution.

[Transcript expression of the CPL 5x, BMD-3A, BMD-10 Interrogans leptospira]

Total RNA of Leptospira interrogans SV Lai strain 017 was prepared by the method of Licl-Urea, and was used in dot hybridization with biotin-labelled DNA probes. The probes included BMD-3A, BMD-10, which were the leptospirial protective antigen genes, and CPL 5x, which was the genus specific gene of interrogans Leptospira. All of the three probes have shown various degrees of hybridization signs, proving that they all have transcript expression in leptospira. The transcript expression is the main way of regulating the gene expression in procaryotae, and it is significant in molecular genetics of Leptospira. The results indicate that the antigens encoded by the BMD-3A, BMD-10 may play an important role in immune reaction against leptospiral infection and provide a clue to the development of gene-engineering vaccine. The results also suggest that the antibody against the antigen encoded by CPL 5x is a useful tool in the classification of Leptospira interrogans.

A new functional classification of stomach cancer and its pathobiological and clinical significance

The functional differentiations of stomach cancer specimens from 121 patients were investigated by enzyme-, mucin-, affinity- and immunohistochemical methods, and the stomach cancers were divided into five functionally differentiated types: 1) Absorptive Function Differentiation Type (AFDT), 19.8%; 2) Mucin Secreting Function Differentiation Type (MSFDT), 24.0%; 3) Absorptive and Mucin-Producing Function Differentiation Type (AMPFDT), 47.1%; 4) Special Function Differentiation Type (SFDT), 0.8%; and 5) Non-Function Differentiation Type (NFDT), 8.3%. The results indicate that stomach cancer tissues of the same histological type often display differing functional differentiation, and these functionally differentiated types have different invasive and metastatic characteristics. In addition, the functionally differentiated types have particular organic affinities of metastasis and different clinical prognoses. This study suggests that this new functional classification may supplement histological classification. The mechanisms of liver and ovary metastases of stomach cancer are also discussed.

Dose-dependency of hepatocellular necrosis in a canine model of chemoembolization

PURPOSE

The degree of local tissue toxicity from hepatic arterial chemoembolization relative to the dose of anticancer drugs was evaluated in 13 dogs.

MATERIALS AND METHODS

Animals were divided into four groups. Group 1 was the control group in which embolization was performed with gelatin sponge particles only (n = 4); group 2 animals underwent embolization with 0.4 mg/kg of Adriamycin (ADR) and 0.2 mg/kg of mitomycin C (MMC) (n = 4); group 3, with 0.8 mg/kg of ADR and 0.4 mg/kg of MMC (n = 2); and group 4, with 1.6 mg/kg of ADR and 0.8 mg/kg of MMC (n = 3).

RESULTS

Animals were killed 1 week after embolization, and histopathologic evaluation was performed. The average percentage liver necrosis in the embolized lobe was 0% in group 1, 1% in group 2, 85% in group 3, and 92% in group 4.

CONCLUSION

Hepatic arterial chemoembolization with high doses of anticancer drugs causes severe liver damage, but 0.4 mg/kg of ADR and 0.2 mg/kg of MMC is relatively safe, causing only minimal changes in this canine model.

In vitro synthesis of human protein synthesis initiation factor 4 gamma and its localization on 43 and 48 S initiation complexes

The rate of protein synthesis is controlled in a large number of physiological situations at the stage of 48 S initiation complex formation, a phase that involves the recruitment of mRNA to the 40 S ribosomal subunit. This process is mediated by the eukaryotic initiation factor-4 (eIF-4) group of translation initiation factors consisting of eIF-4E, eIF-4A, eIF-4B, and eIF-4 gamma. In order to develop a new tool to study this process, we have produced radiolabeled eIF-4 gamma by in vitro transcription and translation. Despite the fact that eIF-4 gamma is predicted from the cDNA sequence to be 154 kDa, the major synthetic product migrated on SDS-polyacrylamide gel electrophoresis at 205 kDa. Although this is similar to the migration of the fastest polypeptide of authentic eIF-4 gamma (approximately 206 kDa), no products were found to co-migrate with the slowest forms of authentic eIF-4 gamma (210-220 kDa), suggesting that these forms derive from extensive modification of the initial polypeptide. The in vitro product also formed a complex with eIF-4E, as judged by its ability to bind to m7GTP-Sepharose. Sucrose gradient sedimentation studies demonstrated that eIF-4 gamma was present on both 43 and 48 S initiation complexes but not 80 S complexes. This supports a model in which free eIF-4E binds to mRNA followed by binding of the eIF-4E.mRNA complex to a 43 S initiation complex already containing eIF-4 gamma.

[Effects of "moist burn ointment--mei bao" on production of IL-2 in burn rats and its clinical problems]

Since "Mei Bao" has been used in clinical treatment of burn wounds, there is a diversity of opinions concerning its effect. We carried out a series of experiments to observe its therapeutic effect, bacteriostatic property, and its effect on production of IL-2 in thermally injured rats. These results indicate that obvious infection occurred after its use on burn wounds and healing is delayed. Hyperplastic scars accompanying with deformity appeared after healing. The cost of treatment is high. There is no improvement in immune reaction, and no bacteriostatic property is observed.

[Preparation of yuanhuacine by low pressure column chromatography]

Preparation of yuanhuacine by low pressure column chromatography gives high separation rate, short washing time and one time crystallization, which comes up to the standard published by the Ministry of Public Health. The method is simple and convenient.

Mapping the cleavage site in protein synthesis initiation factor eIF-4 gamma of the 2A proteases from human Coxsackievirus and rhinovirus

The rate-limiting step of eukaryotic protein synthesis is the binding of mRNA to the 40 S ribosomal subunit, a step which is catalyzed by initiation factors of the eIF-4 (eukaryotic initiation factor 4) group: eIF-4A, eIF-4B, eIF-4E, and eIF-4 gamma. Infection of cells with picornaviruses of the rhino- and enterovirus groups causes a shut-off in translation of cellular mRNAs but permits viral RNA translation to proceed. This change in translational specificity is thought to be mediated by proteolytic cleavage of eIF-4 gamma, which is catalyzed, directly or indirectly, by the picornaviral 2A protease. In this report we have used highly purified recombinant 2A protease from either human Coxsackievirus serotype B4 or rhinovirus serotype 2 to cleave eIF-4 gamma in vitro in the eIF-4 complex purified from rabbit reticulocytes. Neither the rate of cleavage nor fragment sizes were affected by addition of eIF-3. The NH2- and COOH-terminal fragments of eIF-4 gamma were separated by reverse phase HPLC and identified with specific antibodies, and the NH2-terminal sequence of the COOH-terminal fragment was determined by automated Edman degradation. The cleavage site for both proteases is 479GRPALSSR decreases GPPRGGPG494 in rabbit eIF-4 gamma, corresponding to 478GRTTLSTR decreases GPPRGGPG493 in human eIF-4 gamma.

Purification of two picornaviral 2A proteinases: interaction with eIF-4 gamma and influence on in vitro translation

A mammalian cell infected with a human rhinovirus or enterovirus has a much reduced capability to translate capped mRNAs (the host cell shutoff), while still allowing translation of uncapped viral RNA. Biochemical and genetic evidence suggests that the viral proteinase 2A induces cleavage of the eukaryotic initiation factor (eIF) 4 gamma (also known as p220) component of eIF-4 (formerly called eIF-4F). However, neither the mechanism underlying the specific proteolysis of eIF-4 gamma nor the influence of this cleavage on the translation of capped mRNAs has been clarified. Such studies have been hampered by a lack of large quantities of a purified 2A proteinase. Therefore, the mature proteinases 2A of human rhinovirus 2 and coxsackievirus B4 were expressed in soluble form in Escherichia coli. A four-step purification protocol was developed; 1 mg of highly purified 2A proteinase per gram wet weight of E. coli was obtained. Both enzymes cleaved directly eIF-4 gamma as part of the purified eIF-4 complex. Addition of HRV2 2A proteinase to HeLa cell cytoplasmic translation extracts resulted in eIF-4 gamma cleavage and drastically reduced the translation of capped mRNA; addition of purified eIF-4 restored translation to the initial level. However, translation of a reporter gene driven by the 5'-untranslated region of human rhinovirus 2 was translated 2-3-fold more efficiently in the presence of HRV2 2A proteinase.

Amino acid sequence of the human protein synthesis initiation factor eIF-4 gamma

Eukaryotic protein synthesis initiation factor (eIF) 4 gamma, also known as p220, is a component of the protein complex eIF-4, which is involved in the recognition of the mRNA cap, ATP-dependent unwinding of 5'-terminal secondary structure and recruitment of mRNA to the ribosome. Peptide sequence data from rabbit reticulocyte eIF-4 gamma was used to synthesize oligonucleotide probes and polymerase chain reaction primers. These were used to screen lambda-cDNA libraries from rabbit and human brain, yielding a partial rabbit and a complete human cDNA sequence of 5.1 kilobases. Northern blot and primer extension analysis indicated that the cDNA sequence was complete. To confirm that the cDNA represented that of eIF-4 gamma, three peptides were synthesized based on cDNA sequences and used to produce anti-peptide antibodies. The antibodies specifically recognized intact eIF-4 gamma and its cleavage products following poliovirus infection. The eIF-4 gamma mRNA contains AUG codons at nucleotides 6, 67, 90, 165, and 369, but only the last is followed by a long open reading frame. The eIF-4 gamma polypeptide is 154 kDa (1396 amino acid residues) and contains sequence motifs of potential interest: a sequence (AGLGPR) that is similar to the substrate recognition sequence of protease 2A from rhinovirus serotype 14, five PEST regions with scores greater than 10, which are characteristic of rapidly degraded proteins, stretches of polyglutamic acid, and numerous potential phosphorylation sites.

Cyclophosphamide 24 hours before or after total body irradiation: effects on lung and bone marrow

Preparative regimens for bone marrow transplantation (BMT) use a sequence of drugs, such as cyclophosphamide, in combination with radiation. However, the optimum sequencing of the two agents that will maximize tumor cell kill and minimize normal tissue damage is unknown and controversial. The studies presented here were done in order to determine the effect of cyclophosphamide on bone marrow and lung damage in mice when given 24 h before or after total body irradiation (TBI). A range of single doses of TBI was given before or after a single sublethal dose of 180 mg/kg of cyclophosphamide. The bone marrow of all mice intended for lung damage assessment was reconstituted with 5 x 10(6) syngeneic bone marrow cells. Lung damage was assessed by breathing rate and lethality; bone marrow damage by lethality at 30 days. LD50 values for pneumonitis were obtained between 30 and 84 days after cyclophosphamide and radiation and between 80 and 180 days after radiation alone. Dose modifying factors were obtained as the ratio of LD50s for mice given only TBI compared to those for mice given cyclophosphamide and TBI. Cyclophosphamide enhanced radiation pneumonitis when given before or after TBI, giving DMFs of 1.4 and 1.2 (1.1-1.4, 95% c.l.) respectively. The effect of cyclophosphamide on radiation pneumonitis was drug dose-dependent. The LD50 for death from bone marrow damage was reduced when cyclophosphamide was given either before or after TBI but the effect was greater, i.e. the LD50 was lower when cyclophosphamide was given after TBI. These data show that cyclophosphamide given 24 h after TBI causes less lung damage but more bone marrow damage in this mouse model.

[Study on the characteristics of agglutination reaction of McAb with Leptospira interrogans outer envelope]

Three McAb were produced against an outer envelope preparation from Leptospira, interrogans, serovar Lai by fusion of SP2/0 myeloma cells with immune BALB/c mice spleen cells. The fusion rate was 96% and the antibody positive rate was 50%. One of the hybridomas, E4B11C9, reacted with 13 of the 13 serovars of the Icterohaemorrhagiae serogroup in microscopic agglutination test (MAT) but did not react with the 18 representative serovars of L. interrogans and L. biflexa serovar patoc and Leptonema illini. For all non-reactive serovars the MAT titres were greater than 1:25. The McAb, E4B7G5, reacted similarly with all serovars except smithi and tonkini. E4B7D4 reacted also similarly with all serovars except serovars birkini, ndambari, bogvere, smithi and tonkini. Therefore, 3 McAb showed serogroup specificity and partial serogroup specificity by agglutination. The agglutination titres were high and hybridomas were stable, so it might be useful in providing a simple, rapid method for the classification and identification of clinical isolates such as pathogenic L. interrogans in place of the complicated and time-consuming conventional methods.