[Technological study on the supercritical-CO2 fluid extraction of Curcuma longa oils]

This paper first reports technological study on the extraction of Curcuma longa oils by supercritical-CO2 fluid, mainly studies the influence of pressure, temperature, flow rate of CO2 and time on the yield of the oils, determines optimum technology of extracting the oils, analyzes chemical constituents extracted, compares the oils from SFE-CO2 and SD technology, studies industrial test on the SF-CO2 extraction. The results shows pressure and temperature are more important factors of influence; the optimum technological condition is the extracted pressure 25 MPa and temperature 45 degrees C, isolated pressure I 12.5 MPa and temperature I 60 degrees C, isolated pressure II 6MPa and temperature II 38 degrees C, CO2 flow rate 9 Kg/Kg.h, and extracted time 2 h; the constituents from SFE-CO2 and SD methods are identical, but their content has some difference; SFE-CO2 technology is better than that of SD, which is high yield shorter time, etc.; the industrial production of the oils with SFE-CO2 method is available.

[Mutiple factors analysis of the effects of excimer laser photorefractive keratectomy]

PURPOSE

To observe the effect of excimer laser photorefractive keratectomy (PRK) correcting myopia and astigmatism, and to study the related factors.

METHOD

PRK was performed with the aim to correct myopia errors from 1.00 to 16.00 diopters on 529 myopia eyes (306 patients). All eyes were divided into two groups: Group I: -1.00-6.00 D(294 eyes); group II: -6.25-16.00 D(235 eyes). All the patients were followed up for 3 to 12 months.

RESULTS

At postoperative 12 months the rates of uncorrected visual acuity more than or equal to 10/20 or 20/20 were 97.5%, 77.5% in group I, and 80.3%, 32.8% in group II respectively; 92.5% of eyes were within +/- 1.00 diopter of the desired emmetropia in group I, but 42.6% in group II; The influential factors of changes of postoperative diopters was the severity of corneal haze, methods of removing corneal epithelium, intraocular pressure, the central corneal thickness.

CONCLUSION

The excimer laser PRK is regarded to be a very predictable, safe, stable, and effective method to correct myopia up to -6.00 D. Prior to operation, the plan would be disigned according to diopters, ages, corneal thickness intraocular pressure. During operation, the corneal epithelium bad better to be removed by laser.

[Study of supercritical-CO2 fluid extraction in extracting essential oils of Amomun tsao-ko]

Essential oils from Amomum tsao-ko are extracted by supercritical-CO2 fluid and the oils are analyzed by GC-MS. 1, 8-cineole, trans-geraniol eicosatrienoic acid methylester and d-nerolidol of them are the major constitutents, 12 constitutents of them are first obtained from the plant.

Stable injection locking of diode lasers through a phase-modulated double phase-conjugate mirror

The stable injection locking of 0.8-mum diode lasers with a double phase-conjugate mirror (DPCM) was achieved. Phase modulation by piezoelectric transducers allowed us to keep two input beams of the DPCM mutually incoherent during locking. We preserved the high performance of the DPCM and retained stable locking for more than an hour.

Degradation of retinoblastoma protein in tumor necrosis factor- and CD95-induced cell death

The product of the retinoblastoma susceptibility gene, RB, is a negative regulator of cell proliferation. Inactivation of RB does not interfere with embryonic growth or differentiation. However, Rb-deficient embryos show abnormal degeneration of neurons and lens fiber cells through apoptosis, suggesting that RB may protect against programmed cell death. Consistent with this notion, RB is found to be degraded in tumor necrosis factor (TNF)- and CD95-induced death. A consensus caspase cleavage site at the C terminus of RB is cleaved in vitro and in vivo by proteases related to CPP32 (caspase 3). Mutation of the consensus cleavage site generates a cleavage-resistant RB which is not degraded during cell death. Expression of this non-degradable RB is found to antagonize the cytotoxic effects of TNF in Rb-/- 3T3 cells, but this mutant RB cannot attenuate the rapid death induced by anti-CD95 in Jurkat/T cells. These results show that RB is a target of the caspase family of proteases during cell death and suggest that the failure to degrade RB can attenuate the death response toward some but not all death inducers.

Regulation of platelet-activating factor receptor gene expression in vivo by endotoxin, platelet-activating factor and endogenous tumour necrosis factor

A competitive PCR assay was developed to quantify platelet-activating factor (PAF) receptor (PAF-R) transcripts in rat tissues using a synthetic RNA as a competitor. We found PAF-R mRNA constitutively expressed in the eight organs tested, with the ileum containing the highest concentration [(3.49+/-0.15) x 10(7) molecules/microg of RNA]. Significant but lower levels were also detected in the jejunum, spleen, lungs, kidneys, heart, stomach and liver. Furthermore we defined the regulatory role of inflammatory mediators in ileal PAF-R gene expression using a rat model of intestinal injury induced by PAF or lipopolysaccharide (LPS). Injection of LPS or low-dose PAF resulted in a marked increase in ileal PAF-R mRNA within 30 min. The up-regulation on PAF-R elicited by PAF was biphasic, peaking first at 90 min, then again at 6 h. In contrast, LPS elicited a weak monophasic response. The second phase of PAF-R mRNA increase after PAF administration was completely abolished by WEB 2170, a PAF antagonist, and partially inhibited by antitumour necrosis factor (TNF) antibody. These observations indicate the involvement of endogenous PAF and TNF in this event. In conclusion, we found: (a) preferential PAF-R expression in the ileum, suggesting a role for PAF in intestinal inflammation; (b) induction of PAF-R expression in vivo by its own agonist; (c) a complex regulation of PAR-R gene expression in vivo involving a network of various pro-inflammatory mediators.

Overexpression and large-scale production of recombinant L-methionine-alpha-deamino-gamma-mercaptomethane-lyase for novel anticancer therapy

The goal of the next generation of cancer chemotherapy is effective tumor-selectivity. A tumor-selective target with high therapeutic potential is the elevated methionine requirement of tumor cells relative to normal cells. We have termed the elevated requirement for methionine in tumors methionine dependence. To selectively target the methionine dependence of tumors for treatment on a large-scale preclinical and clinical basis, the L-methionine alpha-deamino-gamma-mercaptomethane-lyase (methioninase, METase) gene from Pseudomonas putida has been cloned in Escherichia coli using the polymerase chain reaction (PCR). The METase gene was then ligated into the pT7-7 overexpression plasmid containing the T7 RNA polymerase promoter and recloned in E. coli strain BL21(DE3). The pAC-1 clone was isolated by its yellow-orange color which is due to high enrichment of the pyridoxal phosphate-containing recombinant methioninase (rMETase) and distinguished rMETase-overproducer from rMETase-negative colonies. A scale-up production protocol which contained a heat step, two DEAE Sepharose FF ion-exchange, and one ActiClean Etox endotoxin-affinity chromatography columns has been established. The pAC-1 clone produces rMETase at approximately 10% of the total soluble protein and up to 1 g/liter in shake-flask culture. The protocol can produce therapeutic rMETase at the multi-gram level per batch with high yield (> 60%), high purity (> 98%), high stability, and low endotoxin. Purified rMETase is stable to lyophilization. The t1/2 of rMETase was 2 h when rMETase was administered by i.v. injection in mice. Studies of the antitumor efficacy of rMETase in vitro and in vivo on human tumors xenografted in nude mice demonstrated that all types of human tumors tested including those from lung, colon, kidney, brain, prostate, and melanoma were sensitive to rMETase. In contrast, normal cells were insensitive to rMETase in vitro and correspondingly, no toxicity was detected in vivo at the effective doses. In conclusion, the overexpression clone and large-scale production protocols for rMETase have enabled rMETase to be used as a tumor-selective therapeutic with broad indication and high promise for effective, low-toxicity human cancer therapy.

[The immunologic influence of clinical implantation of the machinable bioactive glass ceramics (MBGC)]

The levels of the immunoglobulins (IgG, IgA, IgM), complements (C3, C4) and circulating immune complex (CIC) of the patients were measured before and after implantation of the machinable bioactive glass ceramics in maxillofacial surgery. No significant changes were detected. The results indicate that the patients' immunologic function and status were not affected by the material and machinable bioactive glass ceramics is good bloodcompatibility.

Directional budding of human immunodeficiency virus from monocytes

Time-lapse cinematography revealed that activated human immunodeficiency virus (HIV)-infected monocytes crawl along surfaces, putting forward a leading pseudopod. Scanning electron micrographs showed monocyte pseudopods associated with spherical structures the size of HIV virions, and transmission electron micrographs revealed HIV virions budding from pseudopods. Filamentous actin (F-actin) was localized by electron microscopy in the pseudopod by heavy meromyosin decoration. Colocalization of F-actin and p24 viral antigen by light microscopy immunofluorescence indicated that F-actin and virus were present on the same pseudopod. These observations indicate that monocytes produce virus from a leading pseudopod. We suggest that HIV secretion at the leading edges of donor monocytes/macrophages may be an efficient way for HIV to infect target cells.

Cell-mediated infection of cervix derived epithelial cells with primary isolates of human immunodeficiency virus

We have previously demonstrated that HIV-infected transformed T-cells or monocytes adhere to monolayers of CD4-negative epithelial cells. Adhesion is soon followed by budding of HIV from infected mononuclear cells onto the surface of epithelial cells. Epithelial cells subsequently take up virus and become productively infected. Based on these findings, we proposed that sexual transmission of HIV may involve cell-mediated infection of intact mucosal epithelia of the urogenital tract. However, it has become increasingly clear that primary cells and HIV strains isolated from patients are more appropriate models for HIV infection than established cell lines and lab strains of virus. In the studies described here, we infected cervix-derived epithelial monolayers with primary monocytes infected with patient isolates of non-syncytial inducing (NSI) macrophage-tropic strains of HIV. Under the culture conditions employed, HIV-infected primary monocytes do not remain adherent to the apical surface of the epithelium, as did HIV-infected transformed cells. Instead, following adherence, the primary cells migrate between epithelial cells. Virus is secreted from a pseudopod as HIV-infected primary monocytes pass between cells of the epithelium. Productive infection of the epithelium was detected by p24 ELISA and PCR Southern blot analysis. Infection can be blocked by sera from HIV-seropositive individuals or by certain sulfated polysaccharides. These findings support the supposition that transmission of HIV may occur via cell-mediated infection of intact epithelia. The observations also hint at the possibility that-HIV-infected monocyte/macrophages in semen or cervical-vaginal secretions could cross intact epithelia by passing between epithelial cells. Blocking studies suggest that it may be possible to inhibit sexual transmission of HIV either by antibodies in genital tract secretions or by a topical formulation containing certain sulfated polysaccharides.

Flunitrazepam effects on human sleep EEG spectra. II: Sigma and beta alterations during NREM sleep

Flunitrazepam (FNZ) is known to enhance the higher EEG frequencies, including sigma (10-15 Hz) and beta (20-28 Hz). Both sigma and beta frequency bands show an inverse relationship with delta (0.3-3 Hz) during NREM periods, as we have previously reported. It is not known whether generation of these two EEG frequencies is mediated by the same or different neuronal mechanisms. In this report, we compare alterations of delta, sigma and beta EEG induced by FNZ (4 mg) orally administered to five healthy male subjects for seven consecutive nights. Sleep EEG on the baseline night (BLN), and the fourth and seventh drug nights (4DN, 7DN) was subjected to fast Fourier transform (FFT) analysis. On drug nights, sigma was enhanced without regard to delta amount, but beta was enhanced only during epochs containing low delta. Thus, sigma and beta EEG were altered differently by the same pharmacological agent. These results suggest that sigma and beta EEG are mediated by different neuronal mechanisms.

[Effect of ginger-processing on l-ephedrine contents in rhizoma Pinelliae]

The contents of l-ephedrine in Rhizoma Pinelliae have been determined to be approximately 3.44 x 10(-3). The contents vary with the five different processing methods in the following order, Pinellia boiled with ginger juice and alum > raw Pinellia > Pinellia dipped in ginger juice > Pinellia boiled only with ginger juice > Pinellia dipped in alum solution. The alum solution and the Pinellia boiled only with ginger juice bear most strongly on the l-ephedrine contents of Pinellia.

Characterization of peroxisome-deficient mutants of Hansenula polymorpha

In the methylotrophic yeast Hansenula polymorpha, approximately 25% of all methanol-utilization-defective (Mut-) mutants are affected in genes required for peroxisome biogenesis (PER genes). Previously, we reported that one group of per mutants, termed Pim-, are characterized by the presence of a few small peroxisomes with the bulk of peroxisomal enzymes located in the cytosol. Here, we describe a second major group of per mutants that were observed to be devoid of any peroxisome-like structure (Per-). In each Per- mutant, the peroxisomal methanol-pathway enzymes alcohol oxidase, catalase and dihydroxyacetone synthase were present and active but located in the cytosol. Together, the Pim- and Per- mutant collections involved mutations in 14 different PER genes. Two of the genes, PER5 and PER7, were represented by both dominant-negative and recessive alleles. Diploids resulting from crosses of dominant per strains and wild-type H. polymorpha were Mut- and harbored peroxisomes with abnormal morphology. This is the first report of dominant-negative mutations affecting peroxisome biogenesis.

PER3, a gene required for peroxisome biogenesis in Pichia pastoris, encodes a peroxisomal membrane protein involved in protein import

PER genes are essential for the biogenesis of peroxisomes in the yeast Pichia pastoris. Here we describe the cloning of PER3 and functional characterization of its product Per3p. The PER3 sequence predicts that Per3p is a 713-amino acid (81-kDa) hydrophobic protein with at least three potential membrane-spanning domains. We show that Per3p is a membrane protein of the peroxisome. Methanol- or oleate-induced cells of per3-1, a mutant strain generated by chemical mutagenesis, lack normal peroxisomes but contain numerous abnormal vesicular structures. The vesicles contain thiolase, a PTS2 protein, but only a small portion of several other peroxisomal enzymes, including heterologously expressed luciferase, a PTS1 protein. These results suggest that the vesicles in per3-1 cells are peroxisomal remnants similar to those observed in cells of patients with the peroxisomal disorder Zellweger syndrome, and that the mutant is deficient in PTS1 but not PTS2 import. In a strain in which most of PER3 was deleted, peroxisomes as well as peroxisomal remnants appeared to be completely absent, and both PTS1- and PTS2-containing enzymes were located in the cytosol. We propose that Per3p is an essential component of the machinery required for import of all peroxisomal matrix proteins and is composed of independent domains involved in the import of specific PTS groups.

Diffractive phase elements for beam shaping: a new design method

A design method based on the Yang-Gu algorithm [Appl. Opt. 33, 209 (1994)] is proposed for computing the phase distributions of an optical system composed of diffractive phase elements that achieve beam shaping with a high transfer efficiency in energy. Simulation computations are detailed for rotationally symmetric beam shaping in which a laser beam with a radially symmetric Gaussian intensity distribution is converted into a uniform beam with a circular region of support. To present a comparison of the efficiency and the performance of the designed diffractive phase elements by use of the geometrical transformation technique, the Gerchberg-Saxton algorithm and the Yang-Gu algorithm for beam shaping, we carry out in detail simulation calculations for a specific one-dimensional beam-shaping example.

An assay for HIV infection of cultured human cervix-derived cells

There is a critical need to develop new strategies to prevent sexual transmission of HIV. Condoms have limited acceptance, and a vaccine may not be available for many years. A vaginal formulation could provide an alternative method if a compound that inhibits sexual transmission of HIV can be identified or synthesized, and if this agent can be formulated for vaginal use. In this report we describe an infection assay for testing compounds that may be useful in a vaginal formulation. This assay system utilizes a cell line (ME-180) derived from the human cervix which, on the basis of morphological features, is an appropriate model of female and male genital and urinary tract epithelia. These cells can be productively infected with HIV upon exposure to HIV-infected T-cell lines. Blocking experiments can be readily carried out in this model because in this p24 ELISA assay system the quantity of virus released by the infected epithelium over a 24-h period is 40 times background.

Active site mapping of the catalytic mouse primase subunit by alanine scanning mutagenesis

In the eukaryotic cell, DNA synthesis is initiated by DNA primase associated with DNA polymerase alpha. The eukaryotic primase is composed of two subunits, p49 and p58, where the p49 subunit contains the catalytic active site. Mutagenesis of the cDNA for the p49 subunit was initiated to demonstrate a functional correlation of conserved residues among the eukaryotic primases and DNA polymerases. Fourteen invariant charged residues in the smaller catalytic mouse primase subunit, p49, were changed to alanine. These mutant proteins were expressed, purified, and enzymatically characterized for primer synthesis. Analyses of the mutant proteins indicate that residues 104-111 are most critical for primer synthesis and form part of the active site. Alanine substitution in residues Glu105, Asp109, and Asp111 produced protein with no detectable activity in direct primase assays, indicating that these residues may form part of a conserved carboxylic triad also observed in the active sites of DNA polymerases and reverse transcriptases. All other mutant proteins showed a dramatic decrease in catalysis, while mutation of two residues, Arg162 and Arg163, caused an increase in Km(NTP). Analysis of these mutant proteins in specific assays designed to separately investigate dinucleotide formation (initiation) and elongation of primer indicates that these two activities utilize the same active site within the p49 subunit. Finally, mutations in three active site codons produced protein with reduced affinity with the p58 subunit, suggesting that p58 may interact directly with active site residues.

The Hansenula polymorpha PER8 gene encodes a novel peroxisomal integral membrane protein involved in proliferation

We previously described the isolation of mutants of the methylotrophic yeast Hansenula polymorpha that are defective in peroxisome biogenesis. Here, we describe the characterization of one of these mutants, per8, and the cloning of the PER8 gene. In either methanol or methylamine medium, conditions that normally induce the organelles, per8 cells contain no peroxisome-like structures and peroxisomal enzymes are located in the cytosol. The sequence of PER8 predicts that its product (Per8p) is a novel polypeptide of 34 kD, and antibodies against Per8p recognize a protein of 31 kD. Analysis of the primary sequence of Per8p revealed a 39-amino-acid cysteine-rich segment with similarity to the C3HC4 family of zinc-finger motifs. Overexpression of PER8 results in a markedly enhanced increase in peroxisome numbers. We show that Per8p is an integral membrane protein of the peroxisome and that it is concentrated in the membranes of newly formed organelles. We propose that Per8p is a component of the molecular machinery that controls the proliferation of this organelle.

Multidrug resistance gene expression in childhood medulloblastoma: correlation with clinical outcome and DNA ploidy in 29 patients

Twenty-nine children treated for medulloblastoma between 1987 and 1991 were reviewed. Thirteen patients with high-risk medulloblastoma characterized by incomplete resection, diploid tumor or subarachnoid dissemination received chemotherapy following radiation therapy. Three received postoperative chemotherapy. Eight patients who had been treated with postoperative radiation therapy also received chemotherapy for recurrent tumors. After a minimum 3-year follow-up period, 16 were alive but 13 had died from recurrent tumors. In order to evaluate the possible participation of P-glycoprotein (Pgp)-mediated multidrug resistance (MDR) in medulloblastoma therapy and its correlation with prognosis, archival specimens were examined by immuno-histochemistry utilizing 3 monoclonal antibodies against Pgp and 6 cases by reverse-transcriptase polymerase chain reaction (RT-PCR) using MDR1-specific primers. Sixteen patients (55%) had MDR expression detected either by 1 of the 3 antibodies or by RT-PCR. DNA ploidy study was also performed on 18 specimens. We correlated patients' outcome with variable factors (extent of surgical resection, chemotherapy, DNA ploidy) and MDR expression. Patients who were treated with radiation therapy and adjuvant chemotherapy had a significantly better (p = 0.036) survival than those with radiation therapy alone, despite the fact that the former group of patients was considered to be high-risk. The extent of surgical resection and DNA ploidy did not correlate with prognosis. However, a statistically significant association was found between MDR expression and outcome (p = 0.007). Among the patients who received chemotherapy, positive MDR expression significantly correlated with poor outcome (p = 0.036). Our results showed that Pgp-mediated intrinsic MDR in medulloblastomas seems to correlate with an adverse outcome. This information may be used in designing new therapeutic protocols for medulloblastoma.

PAF and TNF increase the precursor of NF-kappa B p50 mRNA in mouse intestine: quantitative analysis by competitive PCR

NF-kappa B, a nuclear transcription factor, is involved in the regulation of inflammatory cytokines. We have previously reported that PAF and TNF induce intestinal injury in rats and mice and the interaction of TNF and PAF probably plays a central role in its pathogenesis. In the present study, we developed a competitive PCR method to quantitate the transcripts of NF-kappa B p50/p105 gene, and investigated the effects of PAF and TNF on p50/p105 gene expression in the small intestine of C3H/HeN mice - p105 is the precursor of the p50 subunit of NF-kB. We found that NF-kappa B p50/p105 gene is constitutively expressed in the normal small intestine in small quantities (7.05 +/- 1.04 attomol/micrograms total RNA). PAF at a dose (1 microgram/kg) causing no systemic changes (e.g., hypotension, hemoconcentration), markedly increased intestinal p50/p105 transcripts within 30 min. TNF, at dose (1 mg/kg) also insufficient to induce systemic changes, increased intestinal p50/p105 gene expression, although its effect was much slower than PAF. The effect of TNF was not blocked by WEB 2086, a PAF antagonist. Our results indicate that both PAF and TNF stimulate the expression of NF-kappa B p50/p105 in vivo. However, the mechanisms of their respective actions are probably different.

Mechanisms of sexual transmission of HIV: does HIV infect intact epithelia?

The prevailing view of sexual transmission of HIV has been that the virus enters the body through lesions in the epithelium of the genital tract. We propose that transmission of HIV can occur via the infection of intact epithelial cells, and that it is mediated by HIV-infected mononuclear cells in genital-tract secretions.

Platelet-activating factor and endotoxin induce tumour necrosis factor gene expression in rat intestine and liver

We have shown previously that endotoxin, tumour necrosis factor (TNF) and platelet-activating factor (PAF) are important in the pathogenesis of bowel injury, and that endotoxin and TNF induce PAF formation in bowel tissue. In the present study we investigated the effects of endotoxin and PAF on TNF gene expression. Adult rats were injected with endotoxin (2 mg/kg), PAF (1 microgram/kg) or endotoxin plus PAF, and were killed after 30 min. Endotoxin had little systemic effect. PAF induced transient hypotension and mild bowel injury. Endotoxin plus PAF caused profound shock, severe haemoconcentration, leukopenia and intestinal necrosis. Sham-operated rats had barely detectable TNF mRNA in the liver or intestine. Endotoxin or PAF induced a marked increase in TNF mRNA, especially in the distal ileum and in the liver, but much less in the jejunum. Endotoxin plus PAF did not further increase TNF mRNA, probably due to development of tissue injury. Serum TNF levels in animals treated with endotoxin, PAF and endotoxin plus PAF were elevated. Endotoxin induces TNF gene expression probably via both PAF-dependent and PAF-independent pathways, since TNF mRNA formation was only partially blocked by PAF antagonist.

A light-repressed transcript found in Synechococcus PCC 7002 is similar to a chloroplast-specific small subunit ribosomal protein and to a transcription modulator protein associated with sigma 54

The gene encoding a novel light-repressed transcript (lrtA) contained within a 2.7-kbp EcoRI fragment has been cloned and sequenced from the unicellular cyanobacterium, Synechococcus PCC 7002. Northern analysis indicates that this transcript is synthesized rapidly in the dark, but upon 20 min of illumination, transcript levels fall below detectable limits. An open reading frame was located 378 bases from the start of the transcript which encodes a 21-kDa protein with significant homology to two hitherto different proteins. The protein sequence LrtA showed 37% sequence identity and 58% sequence similarity to the chloroplast-specific small subunit ribosomal protein, S30, and 37% sequence identity and 60% sequence identity and 60% sequence similarity to the reported transcription modulator protein of sigma 54 found in Klebsiella pneumonia and Azotobacter vinelandii. Expression of the lrtA gene product is not detectable within 1 h after placing the cells in the dark, however, within 2.5 min of illumination, [35S]methionine incorporated into a 21-kDa protein. To a lessor extent, [35S]methionine incorporation into a 17- and a 14-kDa protein was also seen which was followed by two other recognizable waves of translation at 5 and 10 min. This incorporation was not blocked by rifampicin added to dark-adapted cells prior to illumination. [35S]Methionine pulsed-labeling experiments suggested that the translation of lrtA occurred only during the first 10 min of reillumination of dark-adapted cells. The loss of initial [35S]methionine labeling in the light of the 21-kDa protein in a kanamycin-interrupted lrtA gene mutant suggests that the lrtA codes for the 21-kDa protein.

Platelet-activating factor, tumor necrosis factor, hypoxia and necrotizing enterocolitis

The pathogenesis of necrotizing enterocolitis (NEC) is poorly understood. We have established several animal models of NEC by using a combination of various stimuli and stress, including endotoxin, PAF, TNF, and hypoxia. We discuss the mechanism of their actions and the possible roles of these factors in the pathogenesis of human NEC.

Effect of moderate hypothermia on lipid peroxidation in canine brain tissue after cardiac arrest and resuscitation

BACKGROUND AND PURPOSE

We sought to examine the effect of moderate hypothermia (30 degrees C to 32 degrees C) initiated after resuscitation on the scavenging systems of free radicals and lipid peroxidation in canine brain tissue after cardiac arrest and resuscitation.

METHODS

Twenty-one dogs were divided into four groups: group A, nonischemic controls (shams) (n = 4); group B, 15-minute cardiac arrest without reperfusion (n = 4); group C, 15-minute cardiac arrest and standard resuscitation (n = 6); and group D, 15-minute cardiac arrest and hypothermic resuscitation (n = 7). During the period of 10 to 120 minutes after resuscitation, brain temperature and core temperature in group D remained at 30 degrees C to 32 degrees C and were 4 degrees C to 5 degrees C lower than in group C. For each dog, a sample of right parietal cerebral cortex was obtained from group A, group B, or from group C and group D at 2 hours after resuscitation. The sample was assayed for tissue malondialdehyde (MDA), the content of reduced glutathione (GSH), and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX).

RESULTS

In group B, a 15-minute cardiac arrest induced an increase in MDA, a significant reduction of GSH, and no change in SOD and GSH-PX activities compared with group A. In group C, there were further increases in MDA and reductions in GSH content and GSH-PX activity compared with group A; SOD activity remained substantially unchanged. The content of MDA was higher in group D than in group A but less elevated in group D than in group C. The GSH content and SOD and GSH-PX activities were significantly higher in group D than in group C.

CONCLUSIONS

Moderate hypothermia initiated after resuscitation can significantly inhibit the accumulation of lipid peroxidation products and the consumption of free radical scavengers in the brain tissue.

Differential expression of keratin 5 gene in non-tumorigenic and tumorigenic rat bladder cell lines

In this study, we attempted to find a gene or genes which were differentially expressed between a non-tumorigenic rat bladder cell line and a highly tumorigenic/metastatic bladder carcinoma cell line that was derived from the former after treatment in vitro with N-methyl-N-nitrosourea. We cloned a rat keratin 5 cDNA by a differential hybridization technique and found that all of the non-tumorigenic cells (7/7) and normal bladder tissue expressed keratin 5, but most of the tumorigenic cells (8/10) did not express keratin 5. Furthermore, in a spontaneously transformed cell line, keratin 5 expression was lost during the transformation process. These results suggest that loss of keratin 5 expression is closely associated with acquisition of a tumorigenic phenotype by rat bladder non-tumorigenic cells.

Productive infection of a cervical epithelial cell line with human immunodeficiency virus: implications for sexual transmission

The human cervix-derived epithelial cell line (ME180) used in this study displays a characteristics epithelial morphology, including numerous desmosomes, tonofilaments, and epidermal filaments. When T-cell lines infected with human immunodeficiency virus (HIV) are added to epithelial cultures, they rapidly adhere to the epithelial monolayer. Within a few minutes, the T cells shed numerous virions into narrow spaces formed between the epithelial cell and the adherent T cells. Virions subsequently enter the ME180 cells via large vesicles. A few days after infection, cytopathic effects and syncytium formation were observed. Infected clones of ME180 cells have remained infected for 8 months. p24 enzyme-linked immunosorbent assay and infectivity assays show that one subclone of the cell line produces virus titers equivalent to those of high-secreting HIV-infected T-cell lines. Electron microscopy reveals numerous virions budding from both the basal and apical surfaces of the epithelium. These observations suggest that cervical epithelium has the potential to serve as a site of HIV infection.

Determination of the kinetics of degradation of 13-cis-retinoic acid and all-trans-retinoic acid in solution

The degradations of 13-cis-retinoic acid and all-trans-retinoic acid in an organic solvent were determined with an HPLC assay. The degradation curves at 70, 50 and 37 degrees C all showed autocatalytic characteristics for both isomers. For this kind of complex reaction, the usual method cannot be used to estimate the shelf-lives and half-lives at room temperature. In this work a new method was developed to directly calculate the shelf-lives and half-lives. From this equation the activation energy was found to change as the multiple step reaction progressed.

Electron nuclear double resonance study of the Mn2+ environs in the oxalate-ATP complex of pyruvate kinase

Electron nuclear double resonance (ENDOR) and the related pulse technique of pulse field sweep EPR (PFSEPR) were used to probe the site I environment of Mn2+ in the oxalate-ATP complex of pyruvate kinase. Assignment of features and an estimate of hyperfine couplings have shown proximity of protons to the metal ions through their dipolar interaction and proximity of 31P and 17O because of a contact interaction from direct Mn(2+)-ligand covalent spin transfer. Since Mn2+ is a spin5/2 ion whose Ms = +/- 1/2, +/- 3/2, and +/- 5/2 electron spin states can all contribute to EPR and ENDOR, we have developed experimental and theoretical strategies for elucidating hyperfine couplings to the Mn2+ electron spin states. Solvent-exchangeable proton ENDOR features were evident with couplings very similar to the hyperfine couplings of H2O in [Mn(H2O)6]2+. ENDOR of exchangeable, more distant protons originated from a dipolar coupling such as could be expected from protons residing 5.5 A from Mn2+ and hydrogen-bonded to a nonliganding oxygen or nitrogen. Nonexchangeable proton ENDOR features indicated dipolar coupling to proton(s) from the protein residing at approximately 4.5 A from the Mn2+. The approximately 4-MHz 31P phosphate hyperfine couplings in Mn(II)-nucleotide models and in pyruvate kinase were similar, but a detailed ENDOR and PFSEPR comparison revealed that the hyperfine coupling to the ATP gamma-phosphate in pyruvate kinase was approximately 10% less than coupling to phosphates of Mn(II)-nucleotides. [In pyruvate kinase only the gamma-phosphate has been shown to bind to Mn2+ at site I (Lodato & Reed, 1987).](ABSTRACT TRUNCATED AT 250 WORDS)

Inhibitory effect of coumarins on HIV-1 replication and cell-mediated or cell-free viral transmission

A single dose of coumarin derivatives, warfarin, 4-hydroxycoumarin and umbelliferone, added at the time of inoculation either by free virus or by contact with U1 monocytes exhibited a dose-dependent inhibitory effect on viral replication in target MOLT-4 lymphocytes observable even at 5 days post infection. In addition, marked decrease of HIV-1 gap p24 release and reduction in reverse transcriptase activity was observed when chronically HIV-infected ACH-2 lymphocytes were treated with coumarins (ED50% range 10(-6)-10(-9) mol/l). However, the intracellular composition of HIV-1 core proteins in drug-exposed cells was not modified. Results suggest that although no complete inhibition of viral production has been observed in vitro this class of drugs may present potential interest as antiviral agents.

Cellular localization of tumor necrosis factor (TNF)-alpha transcripts in normal bowel and in necrotizing enterocolitis. TNF gene expression by Paneth cells, intestinal eosinophils, and macrophages

Tumor necrosis factor-alpha (TNF) has been shown to induce intestinal necrosis in animals. Moreover, plasma TNF levels are elevated in patients with necrotizing enterocolitis. Thus, it is possible that TNF plays a role in the pathogenesis of NEC. In the present study we used in situ hybridization (with human TNF riboprobes) to localize TNF transcripts in the intestinal tissues from normal biopsies and NEC patients. We found that in normal intestine a small amount of TNF mRNA was present only in Paneth cells. In contrast, in the acute stage of NEC, a high amount of TNF transcripts was detected in Paneth cells as well as in infiltrating eosinophils. In one case that showed infiltrating macrophages, TNF mRNA was also detected in these cells. Resident macrophages in the lamina propria and other inflammatory cells were negative for TNF transcripts. Our results suggest that: 1) Paneth cells are the major source of TNF transcripts in normal intestine, and 2) there is a marked increase in TNF mRNA formation in Paneth cells, as well as in infiltrating eosinophils and macrophages in patients with NEC. TNF-containing cells may play an important role in the pathophysiology of NEC.

Stepwise interferometric method of measuring the refractive index of liquid samples

An iterative interferometric technique for accurately determining the refractive index (RI) of liquid samples is presented. The liquid is measured in an extremely stable stepped cell that is inserted into one arm of a Michelson-type interferometer. The uncertainty of the RI measurement is repeatedly improved by taking successive measurements of the interferometric fringe shifts on adjacent steps in the cell. It is shown that in practice the temperature nonuniformity in the liquid limits the ultimate uncertainty of the RI measurement. The RI resolution of the apparatus described is designed to be 4.3 x 10E-6, and the final RI uncertainty is 1.2 x 10E-5 (2sigma) for a liquid with a RI temperature coefficient of 4 x 10E-4.

Demonstration of protein tyrosine phosphatase activity in the second of two homologous domains of CD45

It has been reported that alteration of deletion of critical residues within one of the two homologous protein tyrosine phosphatase (PTPase)-like domains of CD45 completely abolishes all activity, suggesting that only the more N-terminal domain is catalytically active. However, we now demonstrate, by two independent techniques, that the second (C-terminal) domain is also a viable phosphatase. Limited proteolysis by endoproteinase Lys-C or trypsin increased the phosphatase activity toward reduced, carboxymethylated, and maleylated lysozyme approximately 8-fold. A 50-kDa fragment, isolated by ion exchange chromatography, was found to be responsible for this activity. N-terminal sequencing revealed that this fragment includes less than half of the first phosphatase domain and most, if not all, of the second. In a second experiment, 109 residues, including the presumed catalytic region, were removed from domain I by site-directed mutagenesis. Expression of this construct in a mammalian cell line resulted in increased PTPase activity over nontransfected control cells. Isolation of the recombinant CD45 by immunoprecipitation and immunoaffinity chromatography revealed that it had phosphatase activity. Both of these experimental approaches demonstrate that the second conserved PTPase domain of CD45 is a functioning PTPase, but that external regulation may be required to express its activity in the context of the native molecule.

Inhibitory effect of choriocarcinoma-derived high molecular weight factor (HMWF) on lymphocyte proliferation and adhesion to trophoblasts

Trophoblast-secreted soluble factors may deter the immune rejection of the fetus which can occur from interaction between maternal lymphocytes and fetal trophoblasts in decidua. The effect of size-fractionated culture fluid of choriocarcinoma cells on the function of lymphocytic cells was studied. The results show that dialyzed soluble factor (HMWF) of molecular weight > 100 kDa was inhibitory to lymphocyte proliferation in a dose-dependent manner and prevented lymphocyte-to-trophoblast adhesion in a similar fashion. The effect was abrogated by a freezing-thawing process and heat treatment. Similarly, the fractions below 100 kDa size had no effect on lymphocyte functions. Although the nature of HMWF is not yet known, it appears that this factor differs from most of the well-characterized pregnancy factors but is similar to the recently described high molecular weight factor found in primary cultures of trophoblasts and choriocarcinoma lines. The inhibitory effect of trophoblast-derived HMWF on cell-contact-based immune recognition may contribute to maternal tolerance.

Association of mycoplasma with HIV-1 and HTLV-I in human T lymphocytes

Recent findings from a number of investigators suggest associations between mycoplasma and HIV or AIDS. We used a quantitative morphometric technique to analyze electron micrographs of human T lymphocytes that were infected with both mycoplasma and/or HIV-1. We observed that lymphocytes which were associated with HIV-1 were much more likely to be associated with mycoplasma than cells that were not (p < .001). Similarly, cells with associated HTLV-I were more likely to be associated with mycoplasma than cells which were not associated with mycoplasma (p < .0001). In addition, mycoplasma and virus were observed in the same region in 90% of cases. These observations suggest that adherence of mycoplasma to lymphocytes that are chronically infected with human retrovirus may trigger viral release.

HIV-1 infection of the trophoblast cell line BeWo: a study of virus uptake

An in vitro model has made it possible to demonstrate HIV transmission from infected lymphocytes to placental trophoblast cells via endocytosis. Upon addition to cultured trophoblast cells (BeWo), chronically HIV-infected lymphocytic cells (MOLT-4) adhered to the epithelial cells via a complex of newly induced microvilli. Though viruses were infrequently seen in the infected lymphocytic cell line, mature virions appeared promptly and profusely in the interstices between the interdigitating microvilli of the two cell types. Virions appeared to bud from the lymphocyte donor cells at the point of cell-to-cell contact and were rapidly taken up by the trophoblast cells via an endocytic mechanism involving coated pits, endosomes, and lysosomes. Electron microscopic observations suggest that HIV may later escape into the trophoblast cytoplasm by fusing with the endosome membrane or by lysing the lysosome membrane. Coincubation for 1 h was sufficient to establish HIV infection in the trophoblast cell line. Four weeks after thoroughly washing out the donor lymphocytic cells, HIV RNA was demonstrated in clusters of BeWo cells by in situ hybridization, and p24 antigen was localized with immunocytochemistry. Soluble CD4 did not block infection as measured by p24 ELISA. The HIV infection was productive and chronic as demonstrated by cocultivating the BeWo cells with indicator lymphocytes 4 weeks after the initial infection. This study, demonstrating a mechanism of HIV transmission, expands upon previous observations that trophoblast cell lines lacking the CD4 viral receptor can nevertheless be infected by HIV and can support productive infection.

Solid-state stability studies of 13-cis-retinoic acid and all-trans-retinoic acid using microcalorimetry and HPLC analysis

The solid-state stabilities of 13-cis-retinoic acid and all-trans-retinoic acid in the presence and absence of oxygen were investigated. The samples were first evaluated using microcalorimetry. The rate laws of different samples under different conditions were deduced from the shapes of the heat flow curves, and the activation energies of the reactions were determined from Arrhenius plots. Under an air atmosphere, the decomposition of 13-cis-retinoic acid is an autocatalytic reaction, while all-trans-retinoic acid undergoes a zero-order process. The degradation of the two compounds at a selected elevated temperature was also determined utilizing HPLC analysis. This technique confirmed the decomposition kinetics. Hence, their half-lives and shelf lives at room temperature could be calculated. Under a nitrogen atmosphere, the microcalorimetric experiment showed a first-order phenomenon for both samples, but HPLC analysis showed no degradation, suggesting that the two samples, in the absence of oxygen, undergo only a physical change.

An efficient screen for peroxisome-deficient mutants of Pichia pastoris

We describe a rapid and efficient screen for peroxisome-deficient (per) mutants in the yeast Pichia pastoris. The screen relies on the unusual ability of P. pastoris to grow on two carbon sources, methanol and oleic acid, both of which absolutely require peroxisomes to be metabolized. A collection of 280 methanol utilization-defective (Mut-) P. pastoris mutants was isolated, organized into 46 complementation groups, and tested for those that were also oleate-utilization defective (Out-) but still capable of growth on ethanol and glucose. Mutants in 10 groups met this phenotypic description, and 8 of these were observed by electron microscopy to be peroxisome deficient (Per-). In each per mutant, Mut-, Out-, and Per- phenotypes were tightly linked and therefore were most likely due to a mutation at a single locus. Subcellular fractionation experiments indicated that the peroxisomal marker enzyme catalase was mislocalized to the cytosol in both methanol- and oleate-induced cultures of the mutants. In contrast, alcohol oxidase, a peroxisomal methanol utilization pathway enzyme, was virtually absent from per mutant cells. The relative ease of per mutant isolation in P. pastoris, in conjunction with well-developed procedures for its molecular and genetic manipulation, makes this organism an attractive system for studies on peroxisome biogenesis.

Pregnancy hormones, estrogen and progesterone, prevent HIV-1 synthesis in monocytes but not in lymphocytes

Increase in levels of estrogen and progesterone during pregnancy may affect intra-uterine HIV-1 infection through their effect on maternal immunocompetent cells. These hormones were examined for containing HIV-1 production from ACH-2 lymphocytes and U1 monocytes. Neither of the hormones has an effect on ACH-2, but with U1, the physiological concentrations (0.1 microgram 0.1 ng) of progesterone and estrogen demonstrate significant inhibition of HIV-1 release. Except for the highest dose of 1 microgram/ml, the dose-response to progesterone and estrogen was not correlated with the negative influence on proliferation of both types of cells. The results suggest that in vivo low doses of female steroids may display specific antiviral activity in monocytes but not in lymphocytes.

[Chemical constituents of Morinda officinalis How]

This paper reports the identification of four compounds isolated from the cortex of Morinda officinalis growing in Guangdong Province. These compounds are beta-sitosterol (I), 2-methyl-anthraquinone(II), rubiadin-1-methyl ether(III) and 24-ethylcholesterol(VI). Compounds II and VI are isolated from Morinda Genus for the first time.