[Escharectomy during burn shock stage contributed to controlling or alleviating infectious complication]

Among 29 patients with extensive burn, 14 received escharectomy during the shock period, and the other 15 after 96 hrs. LPS and TNF were determined before and after escharectomy 3, 7, 14 and 21 PBD. Incidence of sepsis and subeschar bacterial count were analyzed. Clinical conditions were compared. The results showed that escharectomy during burn shock stage significantly reduced infectious complications in extensively burned patients. We believe that as long as general condition of the patient allowed, early removal of eschar was beneficial in reducing the threat of sepsis.

Binding characteristics of glucocorticoid receptor in synaptic plasma membrane from rat brain

The study was carried out to identify the specific glucocorticoid membrane binding site (GCMB) on synaptic plasma membrane (SPM), and to investigate the ligand binding properties and physico-chemical characteristics of GCMB. The radioligand binding assay showed that tritiated corticosterone ([3H]B) could bind to GCMB specifically with positive cooperativity. For SPM, the binding capacity (R(zero)) was 46.67 +/- 4.62 fmol/mg protein; the dissociation constant (Kd), 97.48 +/- 18.85 nmol/L, and the Hill coefficient, 1.633 +/- 0.082. Various steroids bound with GCMB in the following rank order: RU26752, aldosterone > corticosterone, cortisol > RU26988, progesterone, R5020, triamcinolone acetonide > testosterone, estradiol > RU38486 > dexamethasone. GCMB, which could be solubilized by detergent Triton X-100, showed thermal stability, although it was susceptible to hydrolysis by trypsin and to the reducing agent, mercaptoethanol. The addition of divalent cations (Ca2+, Mg2+) was beneficial to the ligand binding. The results strongly indicate that GCMB, fulfilling the basic criteria for a receptor, constitutes a novel type of glucocorticoid receptor on neuronal membrane which is significantly different from the cytosolic glucocorticoid receptors.

[Placental ureaplasma urealyticum infection and low birth weight]

Ureaplasma urealyticum (UU) infection during pregnancy may result in poor outcome. Placentae from 116 normal healthy pregnancies were cultured for UU with a recovery rate of 28.45%. 94 cases ended by normal vaginal delivery had a UU positive rate of 29.79%. The UU positive rate of 22 placenta from cases by cesarean section was 22.73%. The 2 positive rates showed no difference of significance (P > 0.05). This result indicated that UU infection of the placenta was present before passing through the birth canal and not due to contaminant during delivery. The birth weight of the neonates with positive UU infection was on the average 2,919g, while that in the negative UU cases was 3,490g, being 571g higher than in the positive group (P < 0.01). This study showed that placental infection with UU is associated with a low birth weight.

Expression of cytochrome P450 2D6 in Escherichia coli, purification, and spectral and catalytic characterization

Cytochrome P450 (P450) 2D6 is the classic human liver debrisoquine 4-hydroxylase, the first human P450 for which genetic polymorphism was clearly demonstrated. We prepared 11 different constructs of P450 2D6, with modification at the N-terminus, for expression in Escherichia coli with the vector pCW. These varied considerably in levels of expression of apo- and holoprotein, with the best yield being obtained in a system in which much of the N-terminal hydrophobic segment was removed. Production of holoprotein was highly dependent upon the addition of delta-aminolevulinic acid and FeCl3 to cultures, even though heme production should not be limiting in this system. The expressed protein was not tightly bound to the "heavier" membrane fraction but did not appear to behave as a soluble protein either. A purification strategy was developed involving fractional centrifugation, Triton X-114 phase separation, and flavodoxin affinity chromatography, which led to recovery of apparently electrophoretically homogeneous protein in good yield. Purified P450 2D6 had the expected N-terminal amino acid sequence and catalytic activities toward debrisoquine (4-hydroxylation) and bufuralol (1'-hydroxylation). The availability of a ready source of the recombinant protein should facilitate physical as well as functional studies and antibody production for other uses.

Redundant 3' end-forming signals for the yeast CYC1 mRNA

The cyc1-512 mutation is a 38-bp deletion in the 3' untranslated region of the CYC1 gene, which encodes iso-1-cytochrome c in Saccharomyces cerevisiae. This deletion caused a 90% reduction in the levels of the CYC1 mRNA and protein because of the absence of the normal 3' end-forming signal. Although the 3' end-forming signal was not defined by previous analyses, we report that concomitant alteration by base-pair substitution of three 3' end-forming signals within and adjacent to the 38-bp region produced the same phenotype as the cyc1-512 mutation. Furthermore, these signals appear to be related to the previously identified 3' end-forming signal TATATA. A computer analysis revealed that TATATA and related sequences were present in the majority of 3' untranslated regions of yeast genes. Although TATATA may be the strongest and most frequently used signal in yeast genes, the CYC1+ gene concomitantly employed the weaker signals TT-TATA, TATGTT, and TATTTA, resulting in a strong signal.

[The characteristics of inhalation injury and pulmonary infection in burn patients and the influence on their mortality]

940 patients with thermal injury during the past 14 years were reviewed. Of them, inhalation injury was diagnosed in 75 patients, including 15 mild injury who all survived, 25 moderate injury, of whom 13 died with a mortality rate of 52.0% and 35 severe injury, of whom 31 died with a mortality rate of 88.6%. The data showed that 70% of burn that caused inhalation injury occurred in a closed space and 96% of which also caused facial injury. With the burn extent increasing, the incidence of inhalation injury and pulmonary infection rise correspondingly. The time and incidence of pulmonary infection in the patients with inhalation injury was earlier and higher than that in those without inhalation injury (P < 0.01). With similar burn area and age, the risk of death in the patients with inhalation injury was 17.2 times of the patients without inhalation injury (P < 0.001). Pulmonary infection further increased mortality of the patients (P < 0.001).

Extensive wound excision in shock stage in patients with major burns

To stop excessive plasma loss, alleviate noxious effects of devitalized tissues on the body and shorten the hospitalization time, we performed extensive escharectomy during the shock period in extensively burned patients. Group A consisted of 21 patients aged 9-45 years (26.1 +/- 7.9 years), with a mean total burn area of 63.2% +/- 18.1% TBSA, and full-thickness injury involving 35.9% +/- 19.6% TBSA. The first escharectomy was done at 24.1 +/- 13.9 hours postburn, and excision area averaged 32.3% +/- 6.7% TBSA (24%-46%). In 15 of them, Swan-Ganz catheter was introduced to monitor the hemodynamic changes. It was found that RAP, PAP, PAWP, ABP, HR, CO and CI were all stable during and after the operation. Group B consisted of 29 patients aged 11-50 years (30.4 +/- 11.7 years), in whom escharectomy was begun 4-5 days postburn. The mean healing time of the patients in group A was 33.1 days, shorter than that of group B patients (40.1 days). The duration of hemoconcentration was shorter in group A. The amount of blood transfusion was almost 700 ml less in group A during the first two weeks. Less antibiotics were used with fewer visceral complications in group A. We believe that escharectomy during the burn shock stage is feasible.

[Detection of pathogenic Entamoeba histolytica DNA in liver abscess aspirates with polymerase chain reaction]

Polymerase chain reaction (PCR) was used to diagnose amebic liver abscess by detecting pathogenic Entamoeba histolytica DNA in liver aspirates from patients with liver abscess. Oligonucleotide primers specific for gene encoding of the 30,000 molecule of pathogenic Entamoeba histolytica were used in the test. Liver aspirates from 23 cases with amebic liver abscess as evidenced by typical clinical findings or very high titres of anti-E. Histolytica antibodies with ELISA were found to be positive with PCR. Fourteen control samples (3 cases of bacterial liver abscess, 1 of liver cancer and 10 of abscess in other sites) were all negative to PCR. The results suggest that PCR is a sensitive and useful method for diagnosing amebic liver abscess.

[The damaging effect of activated human neutrophils on isolated perfused rat lungs--the role of elastase]

Human neutrophil and its elastase play an important role in the pathogenesis of various lung diseases. We investigated the damaging effect of human neutrophils stimulated with PMA (phorbol myristate acetate 10ng/ml) or calcium ionophase A23187 (2ng/ml) on isolated perfused rat lungs. The study specimens consisted of 4 groups of animals. A control, B perfused with human neutrophils, C perfused with human neutrophils stimulated with PMA, and D perfused with human neutrophils stimulated with A23187. By using the ELISA method, we found that the level of human neutrophil elastase (HNE) in perfusate increased significantly at 30min (1.68 +/- 0.79ng/ml P < 0.05) and 60min (2.35 +/- 0.87 ng/ml P < 0.01) after PMA stimulating, but the HNE in the lung lavage fluid of the same group only slightly increased and the concentration of protein in lavage fluid did not change. After stimulating with A23187, the concentration of HNE in perfusate increased markedly at 30min (4.03 +/- 1.96ng/ml P < 0.01) and maintained at high level (P < 0.01). There was a significant increase of HNE level in lung lavage fluid (2.49 +/- 0.61ng/ml) from group D rat lungs, compared with group A, B or C, and the protein as well (1.61 +/- 0.58mg/ml P < 0.05). All the results indicate that the stimulated human neutrophils can release elastase in perfused rat lung. Neutrophil stimulated with A23187 can increase pulmonary permeability and injure the lung. We suggest that the lung damage, caused by human neutrophils, may be the effect of neutrophil elastase or the synergistic effect with some other substances derived from neutrophil.

Phospholipid composition of Pneumocystis carinii carinii and effects of methylprednisolone immunosuppression on rat lung lipids

The phospholipid class composition of Pneumocystis carinii carinii freshly isolated from infected lungs generally resembled that of the host lung, suggesting that the parasite scavenges lung alveolar lipids. However, subtle quantitative differences were demonstrated, indicating that the pathogen has the metabolic capacity to de novo synthesize, or at least tailor, its lipids. The concentration of phosphatidylcholine, the major lung surfactant lipid, in the organism was lower than that in lungs of normal and immunosuppressed uninfected rats, and the concentration of phosphatidylinositol was higher. Phosphonolipids were not detected in the organism by chemical analysis and nuclear magnetic resonance spectrometry. The immunosuppressive regimen alone caused increases in both surfactant protein A and the lipid content of the whole lung. The lungs of rats that were subjected to corticosteroid immunosuppression and had heavy parasite loads had dramatically elevated surfactant protein A levels, whereas the lipid contents of these lungs were not different from lipid contents in whole lungs of immunosuppressed uninfected rats. P. carinii was found to concentrate lipids, indicating that a large amount of the lipids in the whole infected rat lung was within the parasites residing in the organ. These observations have important implications relevant to the use of corticosteroid therapy for P. carinii pneumonitis.

Expression of cytochrome P450 3A5 in Escherichia coli: effects of 5' modification, purification, spectral characterization, reconstitution conditions, and catalytic activities

Cytochrome P450 (P450) 3A5 is a human enzyme with 85% amino acid sequence identity to the more predominantly expressed P450 3A4 and has been reported to have overlapping catalytic specificity. The 5'-terminus of a P450 3A5 cDNA was modified for optimal expression in Escherichia coli using the vector pCW, by aligning the MALLLAVFL N-terminal sequence of recombinant bovine P450 17A (H. J. Barnes, M. P. Arlotto, and M. R. Waterman, (1991) Proc. Natl. Acad. Sci. USA 88, 5597-5601) to the 3A5 cDNA. Two constructs were made, differing by their identity with the modified 3A4 N-terminal sequence (E. M. J. Gillam, T. Baba, B-R. Kim, S. Ohmori, and F. P. Guengerich, (1993) Arch. Biochem. Biophys. 305, 123-131). The first modified sequence (3A5#1) was identical to recombinant P450 3A4 up to codon 15, the 3A5 sequence being introduced thereafter. In the other (3A5#2), the successful 3A4 N-terminal nucleotide sequence was attached to codon 30. The yield was greater than fourfold higher in the first construct [up to 260 nmol (liter culture)-1]. The recombinant P450 3A5 (construct 1) was purified to electrophoretic homogeneity using a variation of a three-step procedure developed previously for P450 3A4, with an overall yield of approximately 40%. Purified P450 3A5 was active in nifedipine oxidation, testosterone 6 beta-hydroxylation, aflatoxin 3 alpha-hydroxylation and 8,9-epoxidation, ethylmorphine N-demethylation, erythromycin N-demethylation, and d-benzphetamine N-demethylation. The reconstitution of nifedipine oxidation, testosterone 6 beta-hydroxylation, and the aflatoxin oxidation activities showed dependence upon the presence of cytochrome b5, divalent cations, phospholipid mixtures, glutathione, and cholate similar to that previously found for purified P450 3A4. However, rates of the N-demethylations of ethylmorphine, erythromycin, and d-benzphetamine were as high or higher for P450 3A5 than P450 3A4 and were not particularly dependent upon modifications of reconstitution systems [corrected].

[Preparation and identification of monoclonal antibody against sterigmatocystin]

Compound antigen, bovine serum albumin-sterigmatocystin (BSA-ST) or hemocyanin sterigmatocystin (H-ST) was prepared by converting ST to its hemiacetal group in ST and taking ST conjugated to BSA or H. Balb/c mice were immunized with BSA-ST, and then their spleen cells were isolated and fused with SP2/0 murine myeloma cells. A hybridoma cell strain that could stably secrete monoclonal antibody against ST (McAb-ST) was selected, and both of their ascites and serum were rich in McAb-ST induced by cells of this strain. McAb-ST was identified as Ig-Gi with a molecular weight of 168,000 kd (53,000 for heavy chain and 31,000 for light one), and with an affinity constant of H-ST reaction of 1.29 x 10(9) mol/L measured by indirect competitive enzyme-linked immunosorbent assay (IC-ELISA). Relative cross reaction of McAb-ST with ST analogues was less than 2%. The minimal 0.5 pg/25 microliters of ST can be detected with IC-ELISA using McAb-ST and ST simultaneously, with a linear range of 0.1-10 ng/ml.

[Multiple organ injury after delayed fluid resuscitation in severely scalded rats: role of oxygen free radicals]

Sixty gnotobiotic rats with 5 strains of bacteria in intestine were randomized to 4 groups: (1) Sham injury group (controls, n = 6). (2) Early fluid resuscitation (EFR) group (n = 24), receiving fluid resuscitation (Parkland formula) immediately after scald (40% TBSA, third degree). (3) Delayed fluid resuscitation (DFR) group (n = 24) receiving resuscitation 6 hours later after scald. (4) Treatment group (n = 12) receiving DFR and the therapy of VitC and VitE. At 8, 24, 48 and 72 hours after injury, the animals (n = 6, at each point) were sacrificed and the content of oxygen free radicals (OFR), SOD,GSHPx and MDA in the heart, liver, kidney and lung were determined. Morphological Changes of organs, PaO2, PaCO2 and the content of serum CPK, LDH, GPT, GOT, BUN and Cr were also examined. Both EFR and DFR groups demonstrated elevated content of OFR and MDA and reduced content of SOD and GSHPx in their organs. Morphological and serological changes were also observed. All these changes were more obvious in DFR group than in EFR group. After the treatment of VitC and VitE, the changes were ameliorated. Our results suggested that DFR induced the production of OFR, resulting in lipid peroxidation and that OFR injury might be one of the main factors in the pathogenesis of multiple organ injury after DFR.

Bioactivation of aromatic amines by recombinant human cytochrome P4501A2 expressed in Ames tester strain bacteria: a substitute for activation by mammalian tissue preparations

The most widely used bioassay in genetic toxicology is the Ames test, which combines a bacterial mutagenicity assay (reversion of Salmonella typhimurium histidine-auxotrophic tester strains) with an exogenous bioactivation system (hepatic postmitochondrial supernatant or "S9"). The enzymatic activities of S9 prepared from the tissues of experimental animals are difficult to control. We show that the requirement for S9 can be obviated by the engineered expression of enzymes of bioactivation within the bacterial cell. With this strategy, reactive metabolites are produced inside the bacterial cell, proximate to the genetic target. Species boundaries can be crossed, and chimeric or mutant enzymes can be studied. We have constructed an Ames tester strain, expressing both aromatic amine N-acetyltransferase and human cytochrome P4501A2, which detects aromatic amine mutagenicity in the absence of S9.

Toxicological and chemical evaluation of emissions from carpet samples

This study investigated findings that the off-gassing of certain carpets caused sensory and pulmonary irritation, changes in neurobehavioral signs, and death in exposed mice. Two standard test method measures--one for estimating sensory irritancy (ASTM-E981-84), the other for evaluating the neurotoxic potential of chemicals (functional observational battery)--were coupled with a postmortem assessment to ascertain the mechanism of toxicity. The postmortem evaluation included measurements of hemoglobin, serum clinical chemistries, blood and lung lavage white cell counts and differential, organ weights, and a gross necropsy with a microscopic evaluation of all major organs. The study evaluated three treatment groups composed of two preheated carpet emission exposures and one preheated air-control exposure. No toxic effects were associated with exposure to the off-gassing of the two tested carpets. Clinical chemistry and histopathological alterations were observed with exposure to either filter-air or carpet when compared to nonexposed unrestrained control mice, indicating that the exposure procedure caused significant effects unrelated to carpet emissions. A detailed chemical and microbial evaluation of the carpets and carpet emissions showed volatile organic compounds, pesticide residues, and microbiological flora, but at insufficient quantities to result in acute toxicity. Based on this assessment, there was no indication that exposure to emissions from these two carpets poses a serious health risk.

[Protective effects of vitamin E on impaired neutrophil phagocytic function in patients with severe burn]

The protective effects of vitamin E on impaired neutrophil phagocytic function were observed in 22 patients with severe burn. The results showed that lowering of SOD values, elevation of MDA values significantly elevated and impairment of neutrophil phagocytic function were all more marked in the patients who did not receive vitamin E than that of vitamin E treated groups and the healthy control. It was also found that there was a significant inverse correlation between MDA values of blood plasma and neutrophil phagocyte rate and phagocyte index in the patients without vitamin E treatment. The results suggested that in severely burned patients the use of free radical scavenger and antioxidant could protect the neutrophil function to certain extent. The optimal dosage of vitamin E will be further assessed.

Oxidation of benzo[a]pyrene by recombinant human cytochrome P450 enzymes

The oxidation of benzo[a]pyrene (B[a]P) was examined using reconstituted systems prepared with recombinant human cytochrome P450 (P450) enzymes 1A1, 1A2, 2C8, 2C10, 2E1, and 3A4 and with microsomes prepared from Saccharomyces cerevisiae expressing recombinant human P450s 2C8, 2C9, and 2C18. Products measured by HPLC included the 3- and 9-phenols, the 4,5-, 7,8-, and 9,10-dihydrodiols (detected in the presence of epoxide hydrolase), and products in the polar fraction eluting immediately after the void volume. The most active enzyme in all reactions was P450 1A1. P450 3A4 and P450 1A2 formed appreciable amounts of several of the products, including the 3-phenol. P450 2C enzymes and P450 2E1 formed relatively low amounts of all B[a]P products. Consideration of these patterns along with knowledge of levels of expression of the P450s in human tissues and previous results with microsomes leads to the conclusion that P450 1A1 should dominate the oxidation of B[a]P in tissues where it is present and inducible. In human liver the level of P450 1A1 is low and P450 3A4, P450 2C subfamily enzymes, and P450 1A2 probably all contribute. Of the human P450s considered here, P450 1A2 was the most active hepatic enzyme forming the 7,8-dihydrodiol. 7,8-Benzoflavone stimulated the oxidation of B[a]P by P450 3A4 and inhibited the oxidations catalyzed by P450 1A2. The extent of inhibition of P450 1A1 was less (than with P450 1A2), probably due to the rapid oxidation of 7,8-benzoflavone by P450 1A1. The major 7,8-benzoflavone product appears to be the 5,6-oxide.

Quantitative investigation of in vitro flow using three-dimensional colour Doppler ultrasound

A quantitative in vitro flow study was performed by using a three-dimensional colour Doppler imaging system. This system was based on a clinical ultrasound instrument with its transducer mounted on a motor-driven translation stage. A vascular and tissue-mimicking phantom containing two wall-less vessels, one normal and another stenotic, was used to quantify the measurement accuracy of the flow velocity and the flow field. Steady state flows, having Reynolds numbers ranging between 460 and 1300, were generated by a computer-controlled positive displacement pump. Effects of the parameter settings of the ultrasound instrument on results of the estimation of flow field were also studied. Experimental results show that our three-dimensional colour Doppler system's velocity accuracy was better than 7% of the Nyquist velocity and its spatial accuracy was better than 0.5 mm. The system showed a good correlation (r = 0.999) between the estimated and the true mean flow velocity, and a good correlation (r = 0.998) between the estimated maximum and the true mean flow velocity. This study is our first step toward validating the measurement of the three-dimensional velocity and wall shear stress distributions by using three-dimensional colour Doppler ultrasound

Differential display using one-base anchored oligo-dT primers

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Direct fluorescence analysis of genetic polymorphisms by hybridization with oligonucleotide arrays on glass supports

A simple and rapid method for the analysis of genetic polymorphisms has been developed using allele-specific oligonucleotide arrays bound to glass supports. Allele-specific oligonucleotides are covalently immobilized on glass slides in arrays of 3 mm spots. Genomic DNA is amplified by PCR using one fluorescently tagged primer oligonucleotide and one biotinylated primer oligonucleotide. The two complementary DNA strands are separated, the fluorescently tagged strand is hybridized to the support-bound oligonucleotide array, and the hybridization pattern is detected by fluorescence scanning. Multiple polymorphisms present in the PCR product may be detected in parallel. The effect of spacer length, surface density and hybridization conditions were evaluated, as was the relative efficacy of hybridization with single or double-stranded PCR products. The utility of the method was demonstrated in the parallel analysis of 5 point mutations from exon 4 of the human tyrosinase gene.

[A study on relation between effect of HB vaccination and time of the second injection]

Three kinds of hepatitis B vaccination schedule in neonates were compared. The schedule included 0, 40 day, 6 month; 0, 50 day, 6 month; 0, 60 day, 6 month; and was controlled by the 0, 30 day, 6 month schedule. The results showed that there was no statistically significant difference among three kinds of schedule, no matter who were neonates of HBs Ag-positive mother or neonates of HBsAg-negative mother. These indicated that in areas with poor condition, such as mountain, island, the second injection of hepatitis B vaccine in neonates may be completed within 30-60 days.

High density cultivation of a recombinant CD-1 cell line producing prourokinase using a Biosilon microcarrier culture system

CD-1, a genetically-engineered CHO cell line, was cultivated with a Biosilon microcarrier culture system. We successfully cultivated CD-1 cells to a very high density (over 1 x 10(7) cells/ml). Prourokinase was stably secreted at about 180 IU/10(6) cells/24 h. Experiments showed that CD-1 cells growing on Biosilon microcarriers were able to spontaneously release from the microcarriers, then reattach and proliferate on fresh microcarriers. This makes it very easy to scale up production. The microcarriers could be reused several times without affecting adhesion, proliferation and prourokinase secretion. With CM-PECC membrane radial flow chromatography and MPG chromatography, the prourokinase in conditioned medium could be purified to a specific activity of 1 x 10(5) IU/mg of protein. The purification factor was about 600 fold, and approximately 90% of the biological activity was recovered.