Postexposure immunoprophylaxis of primary isolates by an antibody to HIV receptor complex

mAb B4 is a monoclonal antibody directed against HIV receptor complex. The antibody had broad neutralizing activity against HIV and provided postexposure prophylaxis to hu-peripheral blood leukocyte (PBL)-severe combined immunodeficient mice and chimpanzees. B4 recognized a complex receptor site for HIV on the T cell surface that includes CD4 and also may be influenced by interaction with HIV coreceptors. mAb B4 preferentially neutralized primary HIV-1 isolates compared with T cell line-adapted strains, including syncytium-inducing and non-syncytium-inducing phenotypes, representatives from HIV-1 subtypes A-G, as well as HIV-2, simian immunodeficiency virus, and chimeric simian/human immunodeficiency virus (SHIV). Neutralization was demonstrated in both pre- and postinfection models. The administration of mAb B4 after infectious challenge totally interrupted the infection of hu-PBL-severe combined immunodeficient mice by PBL-grown HIV-1 and the infection of chimpanzees by chimp-adapted HIV-1. This mode of protection suggested that the anti-HIV receptor antibody is efficacious for prophylaxis after exposure to HIV and for prevention of maternal transmission and may be an effective antiretroviral agent for treatment.

Identification and isolation of three proteasome subunits and their encoding genes from Trypanosoma brucei

We have determined peptide sequences of three Trypanosoma brucei proteasome subunit proteins by mass spectrometry of tryptic digests of the proteins purified by two-dimensional (2-D) polyacrylamide gel electrophoresis. Three genes identified by the sequence of their cDNA encode the peptides identified in these three proteins. The three proteins predicted from the gene sequences have significant similarity to other known proteasome subunits and represent an alpha6 type subunit (TbPSA6), and two beta-type subunits belonging to the beta1-type (TbPSB1) and beta2 type (TbPSB2). The sequences of both beta-subunits predict formation of catalytically active subunits through proteolytic processing. The prediction is supported by the presence in each of the two beta-subunits of a tryptic peptide that has the correctly processed N-terminus that creates the threonine nucleophile of the mature protein. This peptide cannot be generated by trypsin because of the required cleavage of a glycine-threonine bond. It is thus likely that there are at least two catalytically active beta-subunits, TbPSB1 and TbPSB2, present in the mature 20S proteasome from T. brucei.

RGD-CAP ((beta)ig-h3) enhances the spreading of chondrocytes and fibroblasts via integrin alpha(1)beta(1)

In previous studies, RGD-CAP (collagen-associated protein containing the RGD sequence) isolated from a collagen fiber-rich fraction of pig cartilage was found to be orthologous to human (beta)ig-h3, which is synthesized by lung adenocarcinoma cells in response to transforming growth factor-beta. In the present study, we examined the effect of recombinant chick RGD-CAP on the spreading of chondrocytes and fibroblasts using RGD-CAP-coated dishes. When rabbit articular chondrocytes, chick embryonic sternal chondrocytes, rabbit peritoneal fibroblasts or human MRC5 fibroblasts were seeded on plastic dishes coated with RGD-CAP, cell spreading was enhanced compared with that on control dishes (bovine serum albumin- or beta-galactosidase-coated dishes). The effect of RGD-CAP on the cell spreading required divalent cations (Mg(2+) or Mn(2+)), and was reduced by EDTA. Monoclonal antibodies (mAbs) to the human integrin alpha(1) or beta(1) subunit, but not to the alpha(2), alpha(3), alpha(5) or beta(2) subunits, suppressed the RGD-CAP-induced spreading of human MRC5 fibroblasts. In a parallel experiment, the mAb to the alpha(5) subunit, but not the mAb to the alpha(1) subunit, suppressed fibronectin-induced spreading of these cells. These findings suggest that RGD-CAP is a novel ligand for integrin alpha(1)beta(1) that dose not bind to the RGD motif. Accordingly, an RGD-CAP fragment, which carries a deletion in the C-terminal region containing the RGD motif, was still capable of stimulating cell spreading.

[Conjugational actinomycetes of plasmid RSF101 from Escherichia coli to the rare actinomyceces of Nocardia asteriodes and Streptoverticillum caespitosus]

RSF1010 is a naturally occurring Escherichia coli broad host-range plasmid about 8.7 kb in size. It can be mobilized at high frequency between different gram-negative bacterial species when transfer functions are available in trans. Following the pioneering work of conjugational transfer of RSF1010 from E. coli to Streptomyces lividans and Mycobacterium smegmatis, the transfer of this plasmid by conjugation from E. coli S17.1 tp two gram-positive rare actinomycetes, Nocardia asteroides 3927 and Streptoverticillum caespitosus ATCC27422 was first time reported in this study. Southern blot analysis of the total DNA extracted from the actinomycetes' exconjugants proved that RSF1010 had been transferred from E. coli into the two new hosts and maintained staby in the exconjugants. Meanwhile, partial deletions of RSF1010 replicon loosing its antibiotics resistance makers were readily detected in E. coli. The implenmentation of this observation was discussed.

[Effect of liposome-C-erbB2 antisense oligodeoxynucleotides on human ovarian cancer cells]

OBJECTIVE

To explore the effects of liposome-C-erbB2 antisense phosphorothioate oligo deoxynucleotides(S-ODNs) on C-erbB2 protooncogene expression and cell proliferation in human ovarian cancer cells.

METHODS

The effects on C-erbB2 protooncogene expression, cell proliferation and cell cycle in human ovarian cancer cells were studied by flow cytometry and 3H-thymidine incorporation.

RESULTS

Liposome-C-erbB2 S-ODNs could reduce C-erbB2 expression and inhibit cell proliferation in human ovarian cancer cells; the effectiveness of liposome-C-erbB2 S-ODNs on the expression of C-erbB2 was much higher than that of C-erbB2 S-ODNs, about 40 times.

CONCLUSIONS

The data in this study suggest that antisense therapy is an useful method of gene therapy in ovarian cancer. The effectiveness of C-erbB2 S-ODNs could be greatly increased by C-erbB2 S-ODNs encapsulated in liposomes.

[The application of microwave irradiation to derivatization]

The methods using microwave irradiation for rapid preparation of acetyl, trifluoroacetyl, pentafluoropyl, heptafluorobutyl and MSTFA derivatives of Morphine, AMP and MAMP were developed. Conventional techniques for the reaction mixture to be heated need 30 min at 60-70 degrees C to form derivatizations, but by microwave irradiation, only 2-3 min is needed. The mass spectral fragmentation patterns and gas chromatographic retention times of the derivatives obtained by both microwave irradiation and conventional heating are similar.

[Study on the analysis of methamphetamine and its metabolite amphetamine in blood and urine]

The methods using GC/MS,GC/FID,GC/NPD for identification and quantification of Methamphetamined(MAMP) and Amphetamine (AMP) in human blood and urine were developed. Using 4-phenylbutylamine as the internal standard, the samples were extracted with 200 microliters cyclohexane and then the 2 microliters cyclohexane was injected into GC or the extracts were derivaized by using microwave irradiation. The methods given allowed simple and rapid procedure, the recoveries were greater than 80% and the sensitivity limits were 2-5 ng/ml. The methods for d/L Enantiomer of MAMP and AMP in human urine was also described, which can be used to determine the source of Amphetamines and determine the toxic effect in the case.

Identification of RIP3, a RIP-like kinase that activates apoptosis and NFkappaB

The tumor necrosis factor receptor 1 (TNFR1) and the Fas receptor recruit complexes formed by the interactions between RIP kinase, TRADD, FADD and RAIDD - adaptor proteins that contain death domains - which in turn recruit other proteins to initiate signaling [1][2][3][4][5]. To identify proteins associated with the TNF signaling pathway, we performed a yeast two-hybrid interaction screen using RIP as bait. We isolated a kinase, RIP3, which shares homology with the kinase domain of RIP and RIP2 (also known as Rick or CARDIAK). RIP3 could be co-immunoprecipitated with RIP, TRAF2 and TNFR1 in mammalian cells. The carboxy-terminal domain of RIP3, like that of RIP, could activate the transcription factor NFkappaB and induce apoptosis when expressed in mammalian cells. Interestingly, this region shares no significant sequence homology to the death domain of RIP, the caspase-recruiting domain (CARD) of RIP2 [6][7][8] or any other apoptosis-inducing domain. As with RIP and RIP2, the kinase domain of RIP3 was not required for either NFkappaB activation or apoptosis induction. Overexpression of a dominant-negative mutant of RIP3 strongly inhibited the caspase activation but not the NFkappaB activation induced by TNFalpha. Therefore, RIP3 appears to function as an intermediary in TNFalpha-induced apoptosis.

[Application of solid-phase microextraction technique to the detection of amphetamines in urine by GC]

A simple and rapid detection of nine amphetamines co-existing in urine was described. In the test, the method of solid-phase micro-extraction (SPME) by GC technique was used. Urine (1.0 ml), NaCl (0.3 g) and 4-phenylbutylamine (internal standard) were added into a vial (1.5 ml), then the sample was adjusted to pH 12 with 10% NaOH and sealed with a teflon-coated septum. After immersion of the SPME fiber (100 PDME) in the sample for 15 min, the SPME needle was inserted into the injection port of the GC and extruded for 3 min. The result showed that each peak from nine amphetamines compounds and internal standard was clearly separated. The calibration curves were linear from 0.2 to 15 micrograms/ml for most of five amphetamines with r between 0.9928-0.9995. The CV were less 10%. It is concluded that the method is simple, quick, accurate and useful for the practical detection of urine concentration of amphetamines.

Isolated tetrasomy 8 in minimally differentiated acute myeloid leukemia (AML-M0)

Tetrasomy 8 as a sole anomaly in hematological disorders is relatively rare. To the best of our knowledge, only 19 such cases have been described in the literature to date. Of them, acute myeloid leukemia (AML) in 13 (M1, one; M2, three; M4, one; M5, eight), acute lymphoblastic leukemia(ALL) in one, myelodysplastic syndrome(MDS) in 3, polycythemia vera(PV) and myelofibrosis(MF), one case each. Their median survival was 20 weeks. Here, we report the first case of a 29-year-old man with minimally differentiated AML (AML-M0) displaying a tetrasomy 8 clone. Immunophenotyping showed positivity with CD33, CD34 and intracellular MPO, but all lymphoid markers tested were negative. Conventional cytogenetics of bone marrow cells showed 84.9% of metaphases with tetrasomy 8 in addition to 15.1% with normal diploidy. However, Fluorescence in situ hybridization(FISH) using a centromeric probe specific for chromosome 8 revealed trisomy 8 in 14.2% of interphase nuclei besides tetrasomy 8 in 82.4%. The patient died four weeks after diagnosis without therapy. In conclusion, these findings suggest that tetrasomy 8 is associated with a heterogeneous group of myeloid disorders and heralds a bad prognosis. It may be a consequence of clonal evolution of trisomy 8.

[Determination of metabolites of heroin in urine and discrimination of heroin abuse]

This article describes a sensitive method that detects morphine, 6-monoacetylmorphine, morphine-3-glucuronide and codeine in urine for qualifying the abuse of heroin. The analytes were extracted by solid phase C18. The limits of detection (LOD) for morphine and codeine were 50 ng/ml and 50 ng/ml, respectively. The RSD of morphine and codeine were 11.3% (n = 5), and 14.2% (n = 5) respectively. For urine, it does not need to be hydrolyzed before extracted, and for all analytes, also need not to be derivated. The difference ratio of morphine and codeine in the chromatography can be used to discriminate between the abuse of heroin and the administration of compound liquorice mixture.

Function of WW domains as phosphoserine- or phosphothreonine-binding modules

Protein-interacting modules help determine the specificity of signal transduction events, and protein phosphorylation can modulate the assembly of such modules into specific signaling complexes. Although phosphotyrosine-binding modules have been well-characterized, phosphoserine- or phosphothreonine-binding modules have not been described. WW domains are small protein modules found in various proteins that participate in cell signaling or regulation. WW domains of the essential mitotic prolyl isomerase Pin1 and the ubiquitin ligase Nedd4 bound to phosphoproteins, including physiological substrates of enzymes, in a phosphorylation-dependent manner. The Pin1 WW domain functioned as a phosphoserine- or phosphothreonine-binding module, with properties similar to those of SRC homology 2 domains. Phosphoserine- or phosphothreonine-binding activity was required for Pin1 to interact with its substrates in vitro and to perform its essential function in vivo.

Diagnosis of mucosa-associated lymphoid tissue (MALT) lymphoma in gastroendoscopic biopsy specimens

We evaluated the diagnostic criteria of gastric lymphoma in endoscopic biopsies.

METHODS

Our study included cases diagnosed as lymphoma by gastroendoscopic biopsy between 1984 and 1994 that were available in the files of the Department of Gastroenterology, Chinese PLA General Hospital.

RESULTS

Among 53,400 cases of gastroendoscopy, we found 1672 (3%) cases of malignant neoplasm that were diagnosed by endoscopic features and histological findings. Thirty-eight cases of primary gastric lymphoma included 22 men and 16 women 16 to 82 years old, with a median age of 47.7. The endoscopy showed the ulcerative type in 12 cases, diffuse infiltrating type in 11 cases, massive infiltrating type in 6 cases, and large mucosal folds type in 4 cases. Five cases had a mixed type pattern of involvement. Histologically, 34 cases showed mucosa-associated lymphoid tissue lymphoma (89.5%), 2 cases had lymphoblastic lymphoma, and 2 cases were unclassifiable because of crush artifact of neoplastic cells. The majority of cases of primary gastric lymphoma have morphologic and clinical features that justify their inclusion in the category of low-grade lymphoma of mucosa-associated lymphoid tissue (MALT).

[Effect of liposome-C-erbB2 antisense oligodeoxynucleotides on the growth and the chemotherapeutic drug sensitivity of human ovarian cancer transplanted in the omentum of nude mice]

OBJECTIVE

To investigate the effects of liposome-C-erbB2 antisense phosphorothioate oligodeoxynucleotides(S-ODNs) on the growth and the chemotherapeutic drug sensitivity of human ovarian cancer transplanted in the omentum of nude mice.

METHODS

Human ovarian cancer transplanted in the omentum of nude mice model was established, then divided into four groups: control group, experimental group, chemotherapeutic group, and experimental + chemotherapeutic group. Different treatments were given respectively. The weight of nude mice was observed and the morphology of tumor cells was observed by electromicroscope.

RESULTS

The growth inhibitory rate in the experimental group was 37%. There were more heterochromatins in the treated tumor cells. The growth inhibitory rate in the experimental + chemotherapeutic group was increased to 50%. There was no obvious alteration in the weight of experimental group.

CONCLUSION

The data in this study suggest that antisense therapy is an useful method of gene therapy in ovarian cancer; Moreover, it could enhance the effectiveness of antitumor drug.

[Analysis of penicillins in whole blood by reversed high-performance liquid chromatography]

A reversed-HPLC method was established to determinate penicillins in whole blood. Thiamphenicol as internal standard was added to 0.5 ml blood. Proteins in blood were precipitated with acetonitrile, then the separate supernatant was directly injected onto the chromatography column. The range of five penicillins' linearities was 0.9918 to 0.9996, their range of relative recovery was 91.75% to 107.33%, their CV was 3.56% to 9.85%. Effects of different storage temperatures on the stability of analytes and interference of other antibiotics were also studied.

Delta9-tetrahydrocannabinol acts as a partial agonist to modulate glutamatergic synaptic transmission between rat hippocampal neurons in culture

Delta9-tetrahydrocannabinol (Delta9-THC) is the principal psychoactive ingredient in marijuana. We examined the effects of Delta9-THC on glutamatergic synaptic transmission. Reducing the extracellular Mg++ concentration bathing rat hippocampal neurons in culture to 0.1 mM elicited a repetitive pattern of glutamatergic synaptic activity that produced intracellular Ca++ concentration spikes that were measured by indo-1-based microfluorimetry. Delta9-THC produced a concentration-dependent inhibition of spike frequency with an EC50 of 20 +/- 4 nM and a maximal inhibition of 41 +/- 3%. Thus, Delta9-THC was potent, but had low intrinsic activity. Delta9-THC (100 nM) inhibition of spiking was reversed by 300 nM N-piperidino-5-(4-chlorophenyl)-1-(2, 4-dichlorophenyl)-4-methyl-3-pyrazole-carboxamide (SR 141716), indicating that the inhibition was mediated by CB1 cannabinoid receptors. Delta9-THC attenuated the inhibition produced by a full cannabinoid receptor agonist, (+)-[2, 3-dihydro-5-methyl-3-[(4-morpholinyl)methyl]pyrrolo-[1,2,3-de]-1, 4-benzoxazin-6-yl](1-napthalenyl)methanone monomethanesulfonate (Win 55212-2), indicating that Delta9-THC is a partial agonist. The effect of Delta9-THC on synaptic currents was also studied. 6-Cyano-2,3-dihydroxy-7-niroquiinoxaline (CNQX)-sensitive excitatory postsynaptic currents were recorded from cells held at -70 mV in the whole-cell configuration of the patch-clamp and elicited by presynaptic stimulation with an extracellular electrode. Win 55212-2 and Delta9-THC inhibited excitatory postsynaptic current (EPSC) amplitude by 96 +/- 2% and 57 +/- 4%, respectively. Excitatory postsynaptic current amplitude was reduced to 75 +/- 5% in the presence of both drugs, demonstrating that Delta9-THC is a partial agonist. The psychotropic effects of Delta9-THC may result from inhibition of glutamatergic synaptic transmission. The modest physical dependence produced by Delta9-THC as well as its lack of acute toxicity may be due to the ability of the drug to reduce, but not block, excitatory neurotransmission.

[A clinicopathological immunohistochemical and cytomorphometric study on midline T cell lymphoma]

One hundred and twenty-two cases of midline malignant reticulosis (MMR) were studied. A series of antibodies including anti-LCA, UCHL-1, L26, CD45R, and anti-lysozyme were used on paraffin sections by ABC and PAP methods. The results were as follows: 112 cases exhibiting T-cell origin, 4 cases showing B-cell origin, and 6 cases being of uncertain lineage. This result is in accordance with the point of view that most of MMR are T cell lymphoma. Two histological types were classified: sarcomatoid type and granulomatoid type. By using image analyzer, the sarcomatoid type was subdivided into small, medium and large cell types. Sixty-two cases with follow-up data were collected for clinicopathologic analysis. One-year and five-year survival rates in cases with different histologic types were compared and statistically analysed. The results showed that the prognosis was closely related to the histological type.

Three novel proteins of the syntaxin/SNAP-25 family

Intracellular membrane traffic is thought to be regulated in part by soluble N-ethylmaleimide-sensitive factor-attachment protein receptors (SNAREs) through the formation of complexes between these proteins present on vesicle and target membranes. All known SNARE-mediated fusion events involve members of the syntaxin and vesicle-associated membrane protein families. The diversity of mammalian membrane compartments predicts the existence of a large number of different syntaxin and vesicle-associated membrane protein genes. To further investigate the spectrum of SNAREs and their roles in membrane trafficking we characterized three novel members of the syntaxin and SNAP-25 (synaptosome-associated protein of 25 kDa) subfamilies. The proteins are broadly expressed, suggesting a general role in vesicle trafficking, and localize to distinct membrane compartments. Syntaxin 8 co-localizes with markers of the endoplasmic reticulum. Syntaxin 17, a divergent member of the syntaxin family, partially overlaps with endoplasmic reticulum markers, and SNAP-29 is broadly localized on multiple membranes. SNAP-29 does not contain a predicted membrane anchor characteristic of other SNAREs. In vitro studies established that SNAP-29 is capable of binding to a broad range of syntaxins.

Infrared spectroscopy in the evaluation of the process of calcification of valvular bioprostheses

BACKGROUND

The methods currently used to analyze the process of calcification of bioprostheses give only global information on calcium deposition. We investigated the potential advantage of infrared spectroscopy, which makes it possible to analyze the various components of the calcification process, ie, lipids, proteins, and calcium deposits.

METHODS

Sixty porcine aortic leaflets were fixed in 0.6% glutaraldehyde and then subsequently implanted in 10-day-old Wistar rats. The valve leaflets were removed 2, 7, 14, 21, 35, and 56 days after implantation.

RESULTS

Before implantation infrared spectroscopic analysis revealed the presence of proteins only. On day 2 after implantation, all valves showed minor lipid deposits. On day 7, amorphous calcium phosphate was detected. Between days 7 and 14, crystalline forms of calcium phosphate appeared and amorphous calcium phosphate progressively changed into carbapatite over the 56-day period.

CONCLUSIONS

Infrared spectroscopy yields valuable additional information on the nature and kinetics of the various components of glutaraldehyde-treated tissues after implantation. It may prove to be important in the evaluation of new techniques of calcium mitigation.

Does glutaraldehyde induce calcification of bioprosthetic tissues?

BACKGROUND

Glutaraldehyde has been said to be responsible in part for the calcification of glutaraldehyde-treated tissues after implantation in animals or humans. We investigated whether the origin of the tissue, autologous or heterologous, could have a more prominent role in the process of calcification.

METHODS

Three-month-old sheep received sheep pericardial samples (n = 133) and human pericardial samples (n = 123) implanted subcutaneously. Samples were treated with 0.6% glutaraldehyde for 5, 10, or 20 minutes or 7 days and then rinsed thoroughly before implantation. Samples were then retrieved after 3 months. Calcium content was assessed by spectrophometry.

RESULTS

The results show a low calcium content in the autologous group (mean 1.14+/-2.07) and a high calcium content in the heterologous group (mean 38.97+/-26). These results were the same regardless of the duration of the treatment.

CONCLUSIONS

Glutaraldehyde treatment (0.6%) does not play a significant role in the calcification of glutaraldehyde-treated tissue regardless of the origin, autologous or heterologous, of the tissue. Glutaraldehyde-treated autologous tissues are associated with an incidence of calcification lower than heterologous tissues.

Heat treatment mitigates calcification of valvular bioprostheses

BACKGROUND

Several techniques have been proposed to mitigate calcification of glutaraldehyde-preserved bioprostheses. None has been fully satisfactory. Knowing that heat induces significant molecular changes, we investigated the potential benefit of the heat treatment of glutaraldehyde-fixed tissues.

METHODS

Samples of porcine valves and bovine pericardium treated in 0.625% glutaraldehyde were submitted to temperatures from 37 degrees to 70 degrees C for 2 to 12 weeks and then implanted subcutaneously in newborn rats for 3 months. In a second protocol, nine heat-treated porcine valve bioprostheses and seven control porcine valve bioprostheses were implanted in the mitral position in sheep for 20 weeks.

RESULTS

Spectrophotometry and x-ray analysis comparing heat-treated versus non-heat-treated tissues showed the following: porcine valve: 6.7+/-2.3 microg Ca/mg (n = 8) versus 239.9+/-2.9 /g Ca/mg (n = 8); bovine pericardium: 19.5+/-8 microg Ca/mg (n = 6) versus 108+/-10.3 microg Ca/mg (n = 8); and porcine valve bioprostheses: 0 versus ++.

CONCLUSIONS

Heat treatment of glutaraldehyde-treated bioprostheses significantly mitigated calcification in both subcutaneous and mitral position.

Neurotoxicity mediated by aberrant patterns of synaptic activity between rat hippocampal neurons in culture

Reducing the extracellular Mg2+ concentration ([Mg2+]o) to 0.1 mM evoked an aberrant pattern of glutamatergic activity in the synaptic network formed by rat hippocampal neurons grown in primary culture. This treatment resulted in a significant increase in neuronal death when maintained for 20-24 h; 0.1 mM [Mg2+]o elicited a stable and repetitive series of intracellular Ca2+ concentration ([Ca2+]i) spikes as indicated by indo-1-based microfluorimetry. Fura-2-based digital imaging experiments found that the [Ca2+]i spikes were synchronized for all the neurons in a given field. Thus electrophysiological recordings from individual cells were reasonable representations of the field as a whole, enabling correlation of electrical activity to viability. Underlying each [Ca2+]i spike was an intense burst of action potentials. Whole cell voltage-clamp experiments showed that a burst was composed of fast action currents superimposed on a slow inward current. The N-methyl--aspartate (NMDA) receptor antagonist CGS19755 (10 microM) blocked [Ca2+]i spiking, the slow inward current, and the cell death induced by low [Mg2+]o. The L-type Ca2+ channel antagonist nimodipine (10 microM) blocked [Ca2+]i spiking, all synaptic activity, and the cell death induced by low [Mg2+]o. The non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 10 microM) exerted variable effects on [Ca2+]i spiking and blocked the slow inward current only when the cells were held at a relatively negative holding potential. CNQX did not afford any protection from 0.1 mM [Mg2+]o-induced neurotoxicity. [Ca2+]i imaging experiments showed that CNQX inhibited [Ca2+]i spiking in a subset of neurons within an active network. Thus, the neurons that were insensitive to CNQX appear to be those that were destined to die. We characterized an in vitro model that allowed us to correlate specific electrophysiological components of glutamatergic synaptic activity to the subsequent viability of the network. A slow NMDA receptor-mediated inward current was required to elicit [Ca2+]i spiking and neurotoxicity. Non-NMDA receptors did not contribute to synaptically mediated cell death in this model. An L-type Ca2+ channel antagonist was neuroprotective when used at concentrations that blocked synaptic activity, suggesting that dendritic L-type Ca2+ channels present a useful target for neuroprotective drugs.

Cannabinoid receptor agonists protect cultured rat hippocampal neurons from excitotoxicity

Cannabinoid receptor agonists act presynaptically to inhibit the release of glutamate. Because other drugs with this action are known to reduce excitotoxicity, we tested several cannabimimetics in a model of synaptically mediated neuronal death. Reduction of the extracellular Mg2+ concentration to 0.1 mM evoked a repetitive pattern of intracellular Ca2+ concentration ([Ca2+]i) spiking that, when maintained for 24 hr, resulted in significant neuronal death. The [Ca2+]i spiking and cell death in this model result from excessive activation of N-methyl-D-aspartate receptors, as indicated by the inhibition of both [Ca2+]i spiking and neuronal death by the N-methyl-D-aspartate receptor antagonist CGS19755 (10 microM). The cannabimimetic drug Win55212-2 (100 nM) completely blocked [Ca2+]i spiking and prevented neuronal death induced by low extracellular Mg2+ concentrations. These effects on [Ca2+]i spiking and viability were stereoselective and were prevented by the CB1 receptor antagonist SR141716 (100 nM). The partial agonist CP55940 (100 nM) also afforded significant protection from excitotoxicity. Cannabimimetic drugs did not protect cells from the direct application of glutamate (30 microM). These data suggest that cannabimimetic drugs may slow the progression of neurodegenerative diseases.

[Epidemiological characteristics of tuberculosis patients complicated with diabetes in Shanghai]

OBJECTIVE

To understand the epidemiological trends and characteristics of tuberculosis patients complicated with diabetes in Shanghai.

METHOD

All the registered tuberculosis (TB) cases from 1992 to 1997 in Shanghai were included in the analysis. The new registration rates and percentages of TB cases complicated with diabetes were calculated.

RESULT

The new registration rate of the cases increased from 0.70/100,000 in 1992 to 2.10/100,000 in 1997 with an annual increase rate of 24.57%. The cases with the complication accounted for 4.86% in 1997. Diabetes tends to be more prevalent among TB patients in urban area. The greater the age, the more diabetes were found in TB patients. A significant difference was also observed between sex. Bacillary positive rate and percentage of infiltration type were higher, and cavity was more common in cases with the complication. The percentage of cases with relapse was also higher.

CONCLUSION

The complication of diabetes significantly affected the epidemiological trend of TB in Shanghai. The diagnosis of diabetes in TB patients should be enforced, and short-course chemotherapy targeting the cases should be investigated.

Mononeuropathy multiplex in hemophilia: an electrophysiologic assessment

Single nerve lesion or mononeuropathy caused by extrinsic compression of hematoma or hemarthrosis is consistently reported for hemophilic patients. To study the manifestation of peripheral nerve lesions, an extensive nerve conduction study of peripheral nerves and specific nerves in correlation with clinical involvement was carried out on 126 hemophilic patients. We found 24 patients with 34 peripheral nerve lesions. The frequency of nerve lesion positively correlated with the severity of hemophilia (p < 0.01) and increasing age (p < 0.05). Nerve lesions occurred more commonly in lower extremities than in upper extremities. The femoral nerve was most commonly involved. Seven patients were identified to have mononeuropathy multiplex with 2 or more nerve lesions involving more than one extremity. All of these patients had chronic condition. Our findings suggest that mononeuropathy multiplex may occur in hemophilic patients.

[Analysis and assessment of meperidine and normeperidine concentrations in urine]

In this study, urine concentrations of meperidine and normeperidine after a single therapeutic dose of meperidine in 5 healthy volunteers have been measured and compared the results to those in meperidine addicts. The results showed that there was a significant difference between two groups in the ratio of metabolite to parent drug. If can be concluded that the ratio should be aid in making a cause of meperidine injection.

[The role of cytokeratin 7 in the differential diagnosis of primary ovarian carcinoma and metastatic ovarian carcinoma originated from the gastrointestinal tract]

OBJECTIVE

To assess the role of cytokeratin 7 monoclonal antibody in the differential diagnosis of primary ovarian carcinoma and metastatic ovarian carcinoma originated from the gastrointestinal tract.

METHODS

Immunohistochemical study using cytokeratin 7 monoclonal antibody and ABC kit.

RESULTS

All the 46 cases of primary ovarian carcinoma were CK 7 positive, while in the metastatic ovarian carcinoma of intestinal origin, all cases remained negative for CK7. Half of the 34 cases of metastatic ovarian carcinoma of gastric origin were CK 7 positive. The positive result of CK7 was significantly higher in the primary ovarian carcinoma than in each group of the metastatic ovarian carcinoma (P < 0.001).

CONCLUSION

CK 7 is seemed to be a useful antibody in the differential diagnosis of ovarian carcinoma.

Role of phosphorylation in determining the backbone dynamics of the serine/threonine-proline motif and Pin1 substrate recognition

Proline residues provide a backbone switch in a polypeptide chain, which is controlled by the cis/trans isomerization about the peptidyl-prolyl bond. Phosphorylation of serine- and threonine-proline motifs has been shown to be a critical regulatory event for many proteins. The biological significance of these motifs has been further highlighted by the discovery of a novel and essential peptidyl-prolyl cis/trans isomerase Pin1. Pin1 is required for progression through mitosis via catalyzing the isomerization of phosphorylated Ser/Thr-Pro motifs specifically present in mitosis-specific phosphoproteins. However, little is known whether the phosphorylation regulates the conformational switch of the Ser/Thr-Pro bonds. Here, we report the synthesis and conformational characterization of a series of peptides that contain the phosphorylated or nonphosphorylated Ser/Thr-Pro motifs. Phosphorylation affected the rate of the cis to trans isomerization of the Thr/Ser-Pro bonds. As determined by a protease-coupled assay, the isomerization rate of phosphorylated Thr-Pro bond was found to be 8-fold slower than that of the nonphosphorylated analogue. Furthermore, studies of the pH dependence of the isomerization of the phosphopeptides reveal that both cis content and the rate constant of prolyl cis to trans isomerization are lower for the dianionic state of the phosphothreonine-containing peptides. These effects of phosphorylation are specific for phosphorylated Ser/Thr since neither phosphorylated Tyr nor glutamic acid was able to affect the prolyl isomerization. Finally, our experiments provide evidence that effective catalysis of cis/trans isomerization of phosphorylated Ser/Thr-Pro bonds by Pin1 is specific to the dianionic form of the substrate. Thus, our results demonstrate that protein phosphorylation specifically regulates the backbone dynamics of the Ser/Thr-Pro motifs and that Pin1 specifically isomerizes the certain conformation of the phosphorylated Ser/Thr-Pro motifs.

The essential mitotic peptidyl-prolyl isomerase Pin1 binds and regulates mitosis-specific phosphoproteins

Phosphorylation of mitotic proteins on the Ser/Thr-Pro motifs has been shown to play an important role in regulating mitotic progression. Pin1 is a novel essential peptidyl-prolyl isomerase (PPIase) that inhibits entry into mitosis and is also required for proper progression through mitosis, but its substrate(s) and function(s) remain to be determined. Here we report that in both human cells and Xenopus extracts, Pin1 interacts directly with a subset of mitotic phosphoproteins on phosphorylated Ser/Thr-Pro motifs in a phosphorylation-dependent and mitosis-specific manner. Many of these Pin1-binding proteins are also recognized by the monoclonal antibody MPM-2, and they include the important mitotic regulators Cdc25, Myt1, Wee1, Plk1, and Cdc27. The importance of this Pin1 interaction was tested by constructing two Pin1 active site point mutants that fail to bind a phosphorylated Ser/Thr-Pro motif in mitotic phosphoproteins. Wild-type, but not mutant, Pin1 inhibits both mitotic division in Xenopus embryos and entry into mitosis in Xenopus extracts. We have examined the interaction between Pin1 and Cdc25 in detail. Pin1 not only binds the mitotic form of Cdc25 on the phosphorylation sites important for its activity in vitro and in vivo, but it also inhibits its activity, offering one explanation for the ability of Pin1 to inhibit mitotic entry. In a separate paper, we have shown that Pin1 is a phosphorylation-dependent PPIase that can recognize specifically the phosphorylated Ser/Thr-Pro bonds present in mitotic phosphoproteins. Thus, Pin1 likely acts as a general regulator of mitotic proteins that have been phosphorylated by Cdc2 and other mitotic kinases.

Structural and phylogenetic analyses of RGD-CAP/beta ig-h3, a fasciclin-like adhesion protein expressed in chick chondrocytes

A cDNA for RGD-CAP/beta ig-h3 was cloned from a chick embryo chondrocyte cDNA library. The deduced amino acid sequence showed that the chick RGD-CAP/beta ig-h3 is 76-77% identical with human, mouse and pig forms of the protein, and 43% identical with human and mouse osteoblast specific factor 2 (OSF2). RGD-CAP/beta ig-h3 contained four internal repeat domains and two highly conserved sequences (H1 and H2) in each repeat. Chick RGD-CAP/beta ig-h3, as well as the mammalian RGD-CAP/beta ig-h3, contained an RGD sequence, which may serve as a recognition sequence for integrins, in the fourth repeat. Database searches revealed that the H1 and H2 sequences are conserved in some secreted or membrane proteins of several species including mammals, insects, sea urchins, plants, yeast and bacteria. Phylogenetic analysis showed that a portion of the common ancestor gene for RGD-CAP/beta ig-h3 and OSF2 was duplicated to form four repeat domains before the separation of the genes followed by the divergence of vertebrate species.

The cannabinoid agonist Win55,212-2 inhibits calcium channels by receptor-mediated and direct pathways in cultured rat hippocampal neurons

The effects of the cannabinoid receptor agonist Win55,212 on Ca2+ channels were studied in rat hippocampal neurons grown in primary culture. Win55,212-2 inhibited whole-cell Ba2+ currents through Ca2+ channels by both CB1 receptor-mediated and direct mechanisms. The concentration dependent inhibition of the current showed two clear phases, a high-affinity receptor-mediated phase (IC50=14+/-2 nM) that was stereoselective and sensitive to a CB1 receptor antagonist, 300 nM SR141716, and a non-saturating phase that was neither stereoselective nor inhibited by SR141716. These concentration-dependent effects were paralleled by Win55212-induced inhibition of glutamatergic synaptic transmission. Win55,212-2 (100 nM) inhibited both omega-agatoxin IVA- and omega-conotoxin GVIA-sensitive currents. Thus, activation of cannabinoid receptors inhibits N- and P/Q-type Ca2+ channels. Activation of cannabinoid receptors inhibited only a fraction of the whole-cell Ca2+ channel current (17+/-2%) even though more than half of the whole-cell Ba2+ current was carried by N- and P/Q-type Ca2+ channels. Concentrations of agonist greater than 1 microM inhibited Ca2+ channels directly.

[Analysis of MDMA and its metabolites in urine by GC and GC/MS]

The purpose of this study is to investigate the metabolism of MDMA in the person and establish the methods for the determination of MDMA and its metabolites in urine. MDMA and its metabolite were isolated from urine by liquid-liquid extraction after acidic or enzymatic hydrolysis and were determined by GC/MS(EI, PCI) and GC/FID. The results showed that MDMA was metabolized to MDA and HMMA in man. MDA in the urine after MDMA administration was approximately 0.10-0.14 that of the parent drug. The sensitivity limits of methods were 2-50 ng/ml, and the recoveries were greater than 85%(CV < 10%). It is concluded that the methods were simple, quick and accurate for determining urine concentration of MDMA addicts. MDA/MDMA Ratio can be used to indicate whether the parent drug is taken alone or in combination with its active metabolite.

Molecular cloning and characterization of CDEP, a novel human protein containing the ezrin-like domain of the band 4.1 superfamily and the Dbl homology domain of Rho guanine nucleotide exchange factors

A cDNA for a novel human protein named CDEP was cloned using the subtractive hybridization method between dedifferentiated cartilage cells and overtly differentiated cartilage cells. CDEP cDNA contained an open reading frame encoding 1,045 amino acids in a total length of 3.4 kb. The deduced amino acid sequence revealed that a single polypeptide contained the ezrin-like domain, which is found in cytoskeleton-associated proteins of the band 4.1 superfamily, and the Dbl homology (DH) and pleckstrin homology (PH) domains, which are conserved in the Rho GEF (guanine nucleotide exchange factor) family. Northern blot analysis demonstrated that CDEP mRNA was expressed not only in the differentiated chondrocytes but also in various fetal and adult tissues. Since members of the band 4.1 superfamily and the Rho GEF family are crucial for microfilament organization, the novel protein CDEP may be involved in the adhesion, proliferation, and differentiation of some cell types including chondrocytes via changes in the cytoskeleton.

Sequence-specific and phosphorylation-dependent proline isomerization: a potential mitotic regulatory mechanism

Pin1 is an essential and conserved mitotic peptidyl-prolyl isomerase (PPIase) that is distinct from members of two other families of conventional PPIases, cyclophilins and FKBPs (FK-506 binding proteins). In response to their phosphorylation during mitosis, Pin1 binds and regulates members of a highly conserved set of proteins that overlaps with antigens recognized by the mitosis-specific monoclonal antibody MPM-2. Pin1 is here shown to be a phosphorylation-dependent PPIase that specifically recognizes the phosphoserine-proline or phosphothreonine-proline bonds present in mitotic phosphoproteins. Both Pin1 and MPM-2 selected similar phosphorylated serine-proline-containing peptides, providing the basis for the specific interaction between Pin1 and MPM-2 antigens. Pin1 preferentially isomerized proline residues preceded by phosphorylated serine or threonine with up to 1300-fold selectivity compared with unphosphorylated peptides. Pin1 may thus regulate mitotic progression by catalyzing sequence-specific and phosphorylation-dependent proline isomerization.

Characterization and cell cycle regulation of the related human telomeric proteins Pin2 and TRF1 suggest a role in mitosis

Telomeres are essential for preserving chromosome integrity during the cell cycle and have been specifically implicated in mitotic progression, but little is known about the signaling molecule(s) involved. The human telomeric repeat binding factor protein (TRF1) is shown to be important in regulating telomere length. However, nothing is known about its function and regulation during the cell cycle. The sequence of PIN2, one of three human genes (PIN1-3) we previously cloned whose products interact with the Aspergillus NIMA cell cycle regulatory protein kinase, reveals that it encodes a protein that is identical in sequence to TRF1 apart from an internal deletion of 20 amino acids; Pin2 and TRF1 may be derived from the same gene, PIN2/TRF1. However, in the cell Pin2 was found to be the major expressed product and to form homo- and heterodimers with TRF1; both dimers were localized at telomeres. Pin2 directly bound the human telomeric repeat DNA in vitro, and was localized to all telomeres uniformly in telomerase-positive cells. In contrast, in several cell lines that contain barely detectable telomerase activity, Pin2 was highly concentrated at only a few telomeres. Interestingly, the protein level of Pin2 was highly regulated during the cell cycle, being strikingly increased in G2+M and decreased in G1 cells. Moreover, overexpression of Pin2 resulted in an accumulation of HeLa cells in G2+M. These results indicate that Pin2 is the major human telomeric protein and is highly regulated during the cell cycle, with a possible role in mitosis. The results also suggest that Pin2/TRF1 may connect mitotic control to the telomere regulatory machinery whose deregulation has been implicated in cancer and aging.

Significance of proliferating cell nuclear antigen expression in liver metastasis of colorectal cancer

PURPOSE

The study contained herein was aimed at finding some possible pathologic factors that have significance for the prediction of liver metastasis in colorectal cancer.

METHOD

Resected specimens of colorectal cancer from 23 patients with liver metastasis and 30 patients without liver metastasis were subjected to pathologic study, including microscopic characteristics and proliferating cell nuclear antigen immunohistochemistry assay.

RESULTS

Strongly positive expression of proliferating cell nuclear antigen was present in 65.21 percent (15/23) of the liver metastasis group, whereas it was found in only 20 percent (6/30) of the group without liver metastasis (P < 0.005). Deeper invasion to the muscularis propria or serosa and less infiltration of lymphocytes surrounding the tumor were more frequently found in the liver metastasis group than in the other group (P < 0.025).

CONCLUSION

Extent of proliferating cell nuclear antigen expression, depth of invasion, and reaction of lymphocyte infiltration of the primary tumor could have predictive significance of colorectal cancer in liver metastasis.

Molecular characterization of the novel basic helix-loop-helix protein DEC1 expressed in differentiated human embryo chondrocytes

The differentiation of human embryo chondrocytes was markedly induced by the addition of Bt2cAMP to the culture medium. Using this culture system, a novel human cDNA for a basic helix-loop-helix (bHLH) protein (named DEC1) expressed primarily in the chondrocytes in response to Bt2cAMP was cloned by the subtractive hybridization method. DEC1 protein consists of 412 amino acids and exhibits structural similarities to the mammalian HES family, Drosophila hairy, and Enhancer of split m7 in the bHLH region. Northern blot analysis showed that DEC1 mRNA was expressed in various tissues including the cartilage, lung, spleen, and intestine, but not in the brain. These findings suggest that the bHLH factor DEC is involved in the control of cell differentiation in several tissues including cartilage.

Characterization of a cartilage-derived 66-kDa protein (RGD-CAP/beta ig-h3) that binds to collagen

A 66-kDa collagen fiber-associated protein (RGD-CAP) was isolated from a fiber-rich fraction of pig cartilage by ultrafiltration and collagen-affinity chromatography. Amino acid sequencing and cDNA cloning indicated that the RGD-CAP is identical or closely related to beta ig-h3 protein which is induced in human adenocarcinoma cells by transforming growth factor-beta (TGF-beta) (Skonier, J., Neubauer, M., Madisen, L., Bennett, K., Plowman, G.D., and Purchio, A.F. (1992) DNA Cell. Biol. 11, 511-522). The RGD-CAP, as well as beta ig-h3, has the RGD sequence in the C-terminal region. The native RGD-CAP bound to type I, II, and IV collagens even in the presence of 1 M NaCl. A recombinant preparation of RGD-CAP expressed in Escherichia coli cells also bound to collagen but not to gelatin. The RGD-CAP mRNA was expressed in chondrocytes throughout all stages, although the expression level was highest during the prehypertrophic stage. In addition, TGF-beta increased the RGD-CAP mRNA level in chondrocyte cultures. Since RGD-CAP transcripts were found in most tissues, this novel collagen-binding protein may play an important role in cell-collagen interactions in various tissues including developing cartilage.

Osteopontin is associated with bioprosthetic heart valve calcification in humans

Calcification of non-osseous tissues such as heart valves or vessels is a major concern in clinical practice. The exact mechanism is still unknown. Numerous studies have shown that mineral deposits of crystalline hydroxyapatite within these tissues were associated with increased non-collagenous protein content. More recently osteopontin was found to be associated with calcification in living tissues such as vessels and native human aortic valves. The aim of this study was to determine whether or not non-collagenous proteins can also be found in non-living tissues such as glutaraldehyde-pretreated porcine valves after implantation in humans. Thirty-eight glutaraldehyde pretreated porcine bioprostheses were studied: 16 not implanted and 22 after 11 years of implantation in the aortic and mitral valve position in humans. In areas of calcification vizualized by Von Kossa staining and microradiography, immunostaining using polyclonal antibodies against calcium-binding proteins showed osteopontin positive staining and no staining for osteocalcin, bone sialoprotein or osteonectin. In uncalcified areas and in non-implanted values, staining for osteopontin or other calcium-binding proteins was negative. Western blot analysis of macroscopically calcified and uncalcified areas showed that several proteins were adsorbed in implanted values and confirmed the presence of osteopontin in the calcified areas, while no immunolabelling was found in non-calcified areas, in uncalcified valves and in non-implanted valves. Thus the presence of osteopontin in the calcified areas of bioprosthetic heart valves implanted in human indicates that this protein is associated with bioprosthetic valvular calcification. Since these values are made of non-living connective tissue, and no cell immunostained for osteopontin was found around the calcified area, this suggests that a non-cellular mediated mechanism involving protein adsorption may play a role in bioprosthetic valvular calcification.

Long-term in vitro culture and characterisation of avian embryonic stem cells with multiple morphogenetic potentialities

Petitte, J.N., Clarck, M.E., Verrinder Gibbins, A. M. and R. J. Etches (1990; Development 108, 185–189) demonstrated that chicken early blastoderm contains cells able to contribute to both somatic and germinal tissue when injected into a recipient embryo. However, these cells were neither identified nor maintained in vitro. Here, we show that chicken early blastoderm contains cells characterised as putative avian embryonic stem (ES) cells that can be maintained in vitro for long-term culture. These cells exhibit features similar to those of murine ES cells such as typical morphology, strong reactivity toward specific antibodies, cytokine-dependent extended proliferation and high telomerase activity. These cells also present high capacities to differentiate in vitro into various cell types including cells from ectodermic, mesodermic and endodermic lineages. Production of chimeras after injection of the cultivated cells reinforced the view that our culture system maintains in vitro some avian putative ES cells.

Cannabinoid receptor agonists inhibit glutamatergic synaptic transmission in rat hippocampal cultures

Activation of cannabinoid receptors inhibits voltage-gated Ca2+ channels and activates K+ channels, reminiscent of other G-protein-coupled signaling pathways that produce presynaptic inhibition. We tested cannabinoid receptor agonists for effects on excitatory neurotransmission between cultured rat hippocampal neurons. Reducing the extracellular Mg2+ concentration to 0.1 mM elicited repetitive, transient increases in intracellular Ca2+ concentration ([Ca2+]i spikes) that resulted from bursts of action potentials, as measured by combined whole-cell current clamp and indo-1-based microfluorimetry. Pharmacological characterization indicated that the [Ca2+]i spikes required glutamatergic synaptic transmission. Cannabinoid receptor ligands inhibited stereoselectively the frequency of [Ca2+]i spiking in the rank order of potency: CP 54,939 > CP 55,940 > Win 55,212-2 > anandamide, with EC50 values of 0.36, 1.2, 2.7, and 71 nM, respectively. CP 55,940 was potent, but not efficacious, and reversed the inhibition produced by Win 55,212-2, indicating that it is a partial agonist. Inhibition of [Ca2+]i spiking by Win 55,212-2 was prevented by treatment of cultures with active, but not heat-treated, pertussis toxin. Win 55,212-2 (100 nM) inhibited stereoselectively CNQX-sensitive excitatory postsynaptic currents (EPSCs) elicited by presynaptic stimulation with an extracellular electrode, but did not affect the presynaptic action potential or currents elicited by direct application of kainate. Consistent with a presynaptic site of action, Win 55,212-2 increased both the number of response failures and the coefficient of variation of the evoked EPSCs. In contrast, cannabimimetics did not affect bicuculline-sensitive inhibitory postsynaptic currents. Thus, activation of cannabinoid receptors inhibits the presynaptic release of glutamate via an inhibitory G-protein.

Proteins and bioprosthetic calcification in the rat model

BACKGROUND AND AIM OF THE STUDY

The mechanism of valvular bioprostheses calcification is still unknown, but early studies showed increased Gla-protein content in calcified valves. Using an experimental model, which reproduces the clinical process, we therefore analyzed the role of minerals and proteins in bioprosthetic valvular calcification.

METHODS

Glutaraldehyde pretreated porcine valves were studied before and after implantation in rats by X-ray, calcium (Ca) and phosphorus (P) measurement, Fourier Transform Infrared (FTIR) spectroscopy, SDS-PAGE and 45Ca ligand blotting of the extracted proteins.

RESULTS

Before implantation, there was no X-ray calcification with very little Ca and P content. After implantation, X-ray calcifications appeared on day seven with increased Ca and P up to day 35 (p < 0.05, ANOVA). FTIR revealed structural proteins alone before implantation, plus minor proportions of lipids on day two, which always preceded Ca and P appearance. Ca and P increased up to day 35, first as amorphous and changed in carbapatite over time. SDS-PAGE before implantation revealed two proteins (66-kD and 54-kD) alone, which were sustained up to day 35. The 66-kD had 45Ca affinity. On day two, many other proteins appeared on SDS-PAGE, four of which (52, 45, 14 and below 14-kD) with 45Ca affinity. Protein pattern did not change from day two to 35.

CONCLUSIONS

Valvular bioprosthesis calcification is associated with progressive increase in Ca and P content and at least five calcium-binding proteins: one intrinsic valvular protein, pre-existing to implantation, plus four other, extrinsic valvular proteins adsorbed within the tissue after implantation.

[Concentrations and size distributions of aerosols in middle summer of Chengdu]

Statistical concentrations and size distributions of aerosols in middle summer of Chengdu city were measured by using optical scattering method. The influence of climate and its daily change affects on the concentration and distribution were analysed. The results showed: many of the distributions agreed with the Junge distribution; the peak concentration appeared near the noon; the relative humidity had strong influence on concentration; the clean-up effect of rain fall was evident. The measured results are useful for evaluating the environmental sanitation of the city.

Calcium mitigation in bioprosthetic tissues by iron pretreatment: the challenge of iron leaching

Preliminary studies in our laboratory have shown that iron pretreatment of glutaraldehyde-preserved tissues inhibited calcification. The present study was designed to further investigate this finding and to optimize the technique. Porcine valve tissue and bovine pericardium preserved in glutaraldehyde and pretreated by iron at different concentrations and incubation times were implanted either subcutaneously in rats or as a mitral valve substitute in sheep. Compared with control groups, calcification was markedly inhibited in the groups pretreated with Fe3+. There was a direct correlation between the degree of calcification and the iron content within the tissue. A minimal iron content within the tissue of 0.5% for porcine valve tissue and 0.2% for pericardial tissue was found to be necessary for calcium mitigation. A progressive leaching of Fe3+ was observed that could be stabilized by using a higher concentration of iron in the solution and or by additional pretreatment in glutaraldehyde at high temperature, but only for subcutaneously implanted tissues. By contrast, leaching was faster and more complete in the iron-pretreated tissue valves placed in the circulating blood environment, therefore resulting in calcified valves. Pretreatment in glutaraldehyde at high temperature (50 degrees C) alone was able to mitigate calcification in both subcutaneous and circulating blood environments, a new finding that may lead to an improved method for glutaraldehyde preservation of tissues.

Do donor or recipient species influence calcification of bioprosthetic tissues?

To determine whether donor or recipient species influence calcification of bioprosthetic tissues, glutaraldehyde-treated valvar or pericardial specimens from different species (calf, sheep, pig) were subcutaneously implanted in different animals (rat, rabbit, cow, hen). Significant differences in the rate of calcification of the implanted specimens were found, which have important practical and theoretical implications for the development of valvular bioprostheses.

Helicobacter pylori-associated gastritis and gastric carcinoma in Beijing

A retrospective study was performed on 500 consecutive gastric biopsies obtained from patients with a diagnosis of gastritis and gastric carcinoma. Overall, Helicobacter pylori was detected in 336 cases (67.2%); it was seen in 82.4% of patients with duodenal ulcer, 80.1% of patients with gastric ulcer, 76.1% of patients with chronic atrophic gastritis, 60.3% of patients with chronic superficial gastritis, and 32.1% of patients with gastric carcinoma. The gastric epithelium colonized by Helicobacter pylori showed characteristic changes including loss of the apical mucous portion of individual cells, dropout of epithelial cells, and erosions. There is a strong suggestion that the inflammation associated with Helicobacter pylori infection plays a role in the pathogenesis of gastric carcinoma.