Cloning of human myeloid-associated differentiation marker (MYADM) gene whose expression was up-regulated in NB4 cells induced by all-trans retinoic acid

A full-length cDNA of 3192 bp isolated from human bone marrow cDNA library was predicted an ORF encoding 298 amino acids. The deduced protein, containing seven putative transmembrane segments and sharing 75.8% amino acid identity with mouse Myadm protein, was named as human MYADM. The results of Northern blot analysis showed that MYADM was ubiquitously expressed in 15 of 16 adult tissues tested, except thymus. To determine whether the novel human gene was involved in hematopoietic differentiation process as mouse Myadm did, we examined the mRNA expressive abundance of this gene between normal bone marrow cells and peripheral blood leukocytes, and detected the expression change in NB4 cells induced by all-trans retinoic acid at different induce time by the semi-quantitative RT-PCR. The results showed that the expression of the novel gene was not only significantly higher in peripheral blood leukocytes than in bone marrow cells, but also significantly up-regulated when the NB4 cells(derived from a patient with acute promyelocytic leukemia) were induced by all-trans retinoic acid (ATRA) for 48hr. It is suggested that human MYADM was also associated with the differentiation of hematopoietic cells or acute promyelocytic leukemia cells. In addition, MYADM was mapped to human chromosome 19q 13.33-q 13.4 by Radiation Hybrid mapping, and it consists of 3 exons and 2 introns and spans a 7.1-Kb genomic region.

[Antagonism of the novel cholinolytic tricyclopinate on nicotinic and muscarinic cholinergic receptors]

Tricyclopinate hydrochloride(TCPN.HCl) and methiodide(TCPN.CH3I) have been identified as new chemical entities. The effects of these two compounds on central and peripheral nicotinic and muscarinic cholinergic receptor activities were investigated. Excitation of the central nicotinic receptors by nicotine produced convulsions in mice. The dose-response curves of nicotine for producing convulsions were shifted rightward by TCPN.CH3I in a paralled manner. Excitation of the central muscarinic receptors by arecoline produced tremors in mice. TCPN.HCl was shown to prevent arecoline-induced tremors. In isolated guinea-pig ileum preparations. TCPN.HCl was found to antagonize nicotine-induced contractions due to excitation of ganglionic nicotinic receptors. In xenopus laevis embryo neuron-muscle co-cultured cells, TCPN.HCl blocked spontaneous miniature endplate currents, and showed preference to blocking the nicotinic receptor ion channels, which had a long open time, and high current amplitude. The anticholinergic effects of TCPN.CH3I were weaker than those of TCPN.HCl. In conclusion, TCPN.HCl has potent effects against nicotinic and muscarinic receptors in the central and periphery nervous systems.

Inducible ablation of adipocytes in adult transgenic mice expressing the E. coli nitroreductase gene

We describe the use of an enzyme prodrug system based on E. coli nitroreductase (NTR) to achieve the specific ablation of adipose tissue. Transgenic mice expressing the NTR gene specifically in the adipose tissue were generated using the adipocyte specific promoter aP2. After treatment with the prodrug CB1954 these mice showed extensive cell depletion in all fat depots; this was directly correlated to both the dose of prodrug and the levels of NTR expression. Higher doses of CB1954 resulted in complete disappearance of visible adipose stores in some transgenic mice. These mice exhibited an impaired ability to thermoregulate body temperature. Lower doses of CB1954 resulted in a partial reduction of the adipose tissue leaving non-expressing cells that escape ablation. These animals show normal levels of blood glucose and triglycerides but have reduced leptin levels. After 30 days they were able to regenerate the fat depots and leptin levels returned to normal but, interestingly, no NTR-expressing cells were detectable. The present model provides a new approach to manipulate the number of adipocytes at different stages of mouse development and provides a new system for the study of fat metabolism especially in abnormal conditions such as obesity and its modulation through manipulation of the target cell population.

Tissue-engineered pancreatic islets: culturing rat islets in the chitosan sponge

Subcutaneous islet transplantation has become an attractive modality. With development of tissue-engineering techniques, it is possible to rectify the disadvantage of poor blood supply in the subcutaneous site by reconstruction of the capillary network. According to reports, the Chitosan sponge (CS) could be used for reconstruction of in vitro capillary-like network and could be used in artificial skin equivalent. In this study, we cultured the islets in CS for future application. CSs, having 200-500 microm pore size, were prepared by freeze-drying method. Rat islets were isolated from the pancreas of Lewis rats (10 weeks old, 280-300 g, male) by collagenase digestion followed by discontinuous dextran gradient centrifugation method. Each 20 islets were seeded equally into the CSs and were cultured for 62 days with various culture media such as RPMI-1640, Dulbecco's modified Eagle's medium (DMEM), and Eagle's MEM. They contained 10% fetal bovine serum (FBS) and 5 ml/L antibiotic-antimycotic mixed stock solution in the culture dishes. Insulin concentration both inside and outside of the islet-seeded CS was measured during culture. Changes in the morphology of islets were also observed in this study. Freshly isolated islets had a loose appearance with an irregular border, and most were seen as a single islet. Occasionally a cluster, consisting of 2-4 islets ranging mainly from 150 to 250 microm in diameter, was observed. Islets cultured in the CSs in different culture media retained initial morphology, which had well-delineated smooth borders for at least 53 days. The insulin release behavior of islets cultured in the CS showed constant secretory capacities for 49 days. After that they exhibited a rapid and definitive decline from the initial insulin release. Until this stage, insulin concentration in the CS was well maintained. The properties were dependent on culture medium used and insulin diffusion released from islets. This experiment is a new study model for establishment of islet culture in a three-dimensional matrix. Also extension of this observation will provide new insights for islet transplantation at the subcutaneous site by a tissue-engineering approach.

Functional comparison of the single-layer agarose microbeads and the developed three-layer agarose microbeads as the bioartificial pancreas: an in vitro study

In this study, the insulin secretory characteristics of the microencapsulated hamster islets were studied during long-term culture. The hamster islets were encapsulated as single-layer agarose microbeads or three-layer agarose microbeads with agarose and agarose containing poly(styrene sulfonic acid) (PSSa), respectively. The influence of PSSa on the function of the rat islets microencapsulted in three-layer microbeads was primarily monitored. The aim of this study was to examine the influence of the PSSa on the in vitro function of the islets encapsulated in the agarose/PSSa microbeads compared with single-layer agarose microbeads during long-term culture. The microbeads were cultured for 30 days in medium of Eagle's MEM at 37 degrees C in 5% CO2 and 95% air. The basal insulin secretion into the culture medium was measured daily during the first 12 days and two times per week until 30 days. The microbeads were subjected to static incubation test on the 10th, 20th, and 30th day during culture. The basal insulin secretion level of the agarose/PSSa microbeads was significantly higher than that of single-layer agarose microbeads. The static incubation tests revealed a similar pattern of insulin secretion from both microbeads when they were exposed to high glucose challenge. In the static incubation test, both could significantly increase insulin release to more than 6.61 times (stimulation index) in response to high glucose stimulation and could significantly decrease when glucose concentration returned from high glucose to low glucose on the 10th, 20th, and 30th day of culture. This study demonstrated that the hamster islets enclosed in agarose/PSSa hydrogel not only continuously secreted basal amounts of insulin, but also maintained their response to high glucose stimulation similar to the agarose microbeads. The above results together with those of our previous in vivo study suggest that the three-layer microbeads (agarose/PSSa) are well suitable for xenotransplantation of islets for the clinical application.

The influence of the anticomplement synthetic sulfonic polymers on the function of pancreatic islets: an in vitro study

In a previous experiment, we demonstrated the anticomplementary efficacy of poly(stryrene sulfonic acid) (PSSa) and poly(2-acrylamido-2-methyl propane sulfonic acid) (PAMPS). The aim of this study was to examine their influence on the function of pancreatic islets in vitro. In this study, after culturing the rat islets with RPMI-1640 culture medium containing different concentrations of soluble PSSa or PAMPS for 24 h at 37 degrees C, we performed morphological and functional examination of the rat islets. We found that the islets maintained their normal morphology regardless of whether they were in the PSSa or PAMPS groups when the concentrations of soluble PSSa or PAMPS in the media were below 1 g/dl. In the static incubation study, the islets cultured in the PAMPS groups showed significantly high insulin secretory response to glucose challenge but those in the PSSa groups lost the response when the concentrations of soluble PSSa or PAMPS in the media were below 1 g/dl. The PAMPS not only had strong anticomplementry effect, but also maintained the good insulin secretory capacity of the islets. These results indicated that PAMPS is a promising bioartificial material for future clinical application of biohybrid artificial pancreas preparation. It is well suitable for xenotransplantation experiments.

Development of a new method to induce angiogenesis at subcutaneous site of streptozotocin-induced diabetic rats for islet transplantation

The subcutaneous space is a potential site for clinical islet transplantation. Even though there are several advantages, poor blood supply at this site mainly causes failure of islet survival. In this study, angiogenesis was induced in advance at the diabetic rats subcutis for islet transplantation by implanting a polyethylene terephthalate (PET) mesh bag containing gelatin microspheres incorporating basic fibroblast growth factor (bFGF) (MS/bFGF) and a collagen sponge. The bFGF was incorporated into gelatin microspheres for controlled release of bFGF. As controls, a PET mesh bag with or without either collagen sponges or MS/bFGF was implanted at the subcutaneous site of diabetic rats. Macroscopic and microscopic examinations revealed the formation of capillary network in and around the PET mesh bag containing MS/bFGF and collagen sponges 7 days after implantation when compare with other control groups. When tissue hemoglobin level was also measured, a significantly high level of hemoglobin amount was observed compared with that of control groups. When allogeneic islets mixed with 5% agarose were transplanted into the prevascularized rat subcutis, normoglycemia was maintained for more than 40 days, while other control groups were ineffective. This study demonstrated that combination of gelatin microspheres incorporating bFGF and collagen sponges enabled the mesh to induce neovascularization even at the subcutaneous site of streptozotocin-induced diabetic rats, resulting in improved function of islet transplantation.

[Clinical comparison of bilateral neck dissection for supraglottic carcinoma]

OBJECTIVE

In order to rise the survival rate and quality of life, the patients with bilateral neck dissection was investigated in supraglottic carcinoma.

METHOD

76 cases were retrospectively analyzed. In terms of clinical diagnosis, 33 cases who had bilateral neck metastasis had received simultaneously bilateral neck dissection. 43 patients first diagnosed unilateral neck metastasis got subsequent bilateral neck dissection. All of the patients were pathologically diagnosed.

RESULT

The 3 and 5 year survival rates, in the 33 cases who had received simultaneous bilateral neck dissection, were 81.5% (22/27) and 61.5%(16/26) respectively, while in the other 43 cases, was 69.2%(27/39) and 27.8%(10/36) respectively.

CONCLUSION

It is necessary for those patients who have suffered from supraglottic carcinoma with bilateral neck metastasis to have simultaneous bilateral neck dissections. Meanwhile, the preservation of bilateral internal jugular veins is the best choice, at least one should be preserved.

Improved immnunophenotyping of lymphocytes in bronchoalveolar lavage fluid (BALF) by flow cytometry

BACKGROUND

The immnunophenotyping of lymphocytes in bronchoalveolar lavage fluid (BALF) is of particular importance in the differential diagnosis of interstitial lung disorders. The standard method of lymphocyte phenotyping is peroxidase-anti-peroxidase technique (PAP). However, it was time-consuming and experience-dependent. Flow cytometric (FCM) analysis of BALF lymphocytes was introduced to overcome these disadvantages. Unfortunately, when the number of cells counted was small, FCM could not distinguish lymphocytes from other cells and particles in BALF by light scattering.

METHODS

We established a tri-color flow cytometric approach to phenotyping of lymphocytes in BALF. FITC-CD45/PE-CD14 antibodies were used to gate lymphocytes and exclude other contamination. Propidium iodide (PI) was introduced to distinguish lymphocytes from debris. Forty-three BALF species were tested by flow cytometer as well as peripheral blood as a control group by conventional PAP method.

RESULTS

The variation of FCM (CV<1.0%) was much lower that that of PAP method (CV>9.8%). Meanwhile, we found that BALF had more clinical significance than peripheral blood in T subset analysis (p<0.01). There were characteristic changes in some lung diseases. Both CD3 and CD4 were significantly increased with decreasing CD8 in sarcoidosis (n=14). Idiopathic pulmonary fibrosis (n=16) demonstrated the reverse tendency: CD8 rose but both CD3 and CD4 dropped. As for lung cancer (n=7), CD3 was normal but the CD4/CD8 ratio declined. Tuberculosis of the lungs (n=6) showed a normal CD3, CD4 and CD8.

CONCLUSIONS

The high precision and reliability of tri-color flow cytometric approach to phenotyping of lymphocytes in BALF suggested that it should be used as a routine test, especially of BALF, which was often contaminated by inorganic particles.

Method for determination of pentobarbital in dry dog food by gas chromatography/mass spectrometry

A procedure has been developed and validated for measuring the concentration of pentobarbital residues in dry, extruded animal feed in the range of 3-200 ng/g (ppb) with an estimated limit of quantitation of 2 ppb. The method was developed for surveillance purposes: to measure the concentration of euthanizing agent which might be present in feeds incorporating rendered products which themselves might include some fraction of euthanized animals. A previously published qualitative procedure was modified by adding isotopically labelled pentobarbital as an internal standard. Dry feed was ground and extracted with methanol. The extract was loaded on a mixed-mode (C-18, anion exchange) solid-phase extraction cartridge designed for barbiturate residues. Pentobarbital was eluted and derivatized for gas chromatography/mass spectrometry in positive ion chemical ionization mode. Quantitation was based on the ratio of dimethyl-pentobarbital MH+ (m/z 255) vs dimethyl-pentobarbital-d(5) (m/z 260) in standards and extracts. Accuracy ranged from 112% at 3 ppb to 96% at 200 ppb, with relative standard deviations ranging from 4% at 3 ppb to 2% at 200 ppb.

Long-term expression of a transferred gene in Epstein-Barr virus transformed human B cells

Delivering a gene into the Epstein-Barr virus (EBV)-transformed B cells is useful in studying effects of the gene on B-cell functions. However, although people have been able to efficiently transfer genes into and get them expressed in B-lympho blastoid cells for a time probably long enough to kill the cells using vectors harbouring oriP, the expression time of the delivered gene is not long enough in order to study the gene function in B cells. To solve this problem, we constructed an adeno-associated virus (AAV) plasmid pAGX(+) based on plasmids pSub201 and pRc/CMV. We developed and packaged recombinant AAV (rAAV) expression vectors containing an antisense or a sense DNA fragment of 6A8 cDNA encoding a human alpha-mannosidase, or an antisense fragment of 5D4 cDNA encoding a human cell membrane protein, or EYFP DNA. EBV-transformed B cell SKW6 and 3D5 were transduced with those rAAV or the mock. Transduction with the rAAV-EYFP showed an infection frequency of 64 +/- 3.5% and 58 +/- 6.2% for SKW6 and 3D5 cell, respectively. Genomic polymerase chain reaction (PCR) for neoR gene indicated an integration of the transferred gene into the host DNA. After being cultured and propagated for over 12 months, the cells were detected for the expression of the transferred gene. The RT-PCR, enzymatic assay and Con A binding test demonstrated an inhibition of 6A8 alpha-mannosidase in both SKW6 and 3D5 cells transduced with the antisense 6A8 DNA. Immunofluorescence staining with monoclonal antibodies (MoAb) 5D4 showed a reduction of the 5D4 protein expression on both the cells transduced with the antisense 5D4 DNA. The DNA fragmentation assay showed a resistance of the cells with 6A8 alpha-mannosidase inhibition to apoptosis induction by anti-Fas antibody. The data indicate that the AAV vector pAGX(+) can efficiently introduce genes into EBV-transformed B cells and the delivered gene can be expressed in the cells for more than 12 months which may be long enough for the study of gene functions in B cells.

Development and certification of a coal fly ash certified reference material for selected polycyclic aromatic hydrocarbons

The development and certification of a coal fly ash certified reference material (CRM) for polycyclic aromatic hydrocarbons (PAH) is described; this is the first natural matrix CRM for organic environmental analysis in China. The homogeneity and stability of this material have been tested by HPLC. The concentrations of several PAH were determined by use of two independent, different methods--solvent extraction-HPLC analysis with UV detection coupled with fluorescence detection (FLD) and solvent extraction, isolation with a silica column, and GC analysis with flame ionization detection (FID). Five certified values were determined: phenanthrene 7.1 +/- 2.6 microg g(-1), anthracene 2.0 +/- 0.8 microg g(-1), fluoranthene 7.4 +/- 1.9 microg g(-1), pyrene 7 +/- 2 microg g(-1), and benzo[a]pyrene 1.3 +/- 0.3 microg g(-1). Reference values for several other PAH are also suggested.

Conditional ablation of neurones in transgenic mice

Conditional targeted ablation of specific cell populations in living transgenic animals is a very powerful strategy to determine cell functions in vivo. This approach would be of particular value to study the functions of distinct neuronal populations; however, the transgene of choice for conditional cell ablation studies in mice, the herpes simplex virus thymidine kinase gene, cannot be used to ablate neurones as its principal mode of action relies on cell proliferation. Here we report that expression of the E.coli nitroreductase gene (Ntr) and metabolism of the prodrug CB1954 (5-aziridin-1-yl-2-4-dinitrobenzamide) to its cytotoxic derivative can be used to conditionally and acutely ablate specific neuronal populations in vivo. As proof of principal, we have ablated olfactory and vomeronasal receptor neurones by expressing Ntr under the control of the olfactory marker protein (OMP) gene promoter. We demonstrate that following CB1954 administration, olfactory and vomeronasal receptor neurones expressing the transgene were selectively eliminated from the olfactory epithelium (OE), and projections to the olfactory bulb (OB) were lost. The functional efficacy of cell ablation was demonstrated using a highly sensitive behavioural test to show that ablated mice had lost the olfactory ability to discriminate distinct odors and were consequently rendered anosmic. Targeted expression of Ntr to specific neuronal populations using conventional transgenes, as described here, or by "knock-in" gene targeting using embryonic stem cells may be of significant value to address the functions of distinct neuronal populations in vivo.

Presenilin-1 binds cytoplasmic epithelial cadherin, inhibits cadherin/p120 association, and regulates stability and function of the cadherin/catenin adhesion complex

Here we show that presenilin-1 (PS1), a protein involved in Alzheimer's disease, binds directly to epithelial cadherin (E-cadherin). This binding is mediated by the large cytoplasmic loop of PS1 and requires the membrane-proximal cytoplasmic sequence 604-615 of mature E-cadherin. This sequence is also required for E-cadherin binding of protein p120, a known regulator of cadherin-mediated cell adhesion. Using wild-type and PS1 knockout cells, we found that increasing PS1 levels suppresses p120/E-cadherin binding, and increasing p120 levels suppresses PS1/E-cadherin binding. Thus PS1 and p120 bind to and mutually compete for cellular E-cadherin. Furthermore, PS1 stimulates E-cadherin binding to beta- and gamma-catenin, promotes cytoskeletal association of the cadherin/catenin complexes, and increases Ca(2+)-dependent cell-cell aggregation. Remarkably, PS1 familial Alzheimer disease mutant DeltaE9 increased neither the levels of cadherin/catenin complexes nor cell aggregation, suggesting that this familial Alzheimer disease mutation interferes with cadherin-based cell-cell adhesion. These data identify PS1 as an E-cadherin-binding protein and a regulator of E-cadherin function in vivo.

Inducible ablation of astrocytes shows that these cells are required for neuronal survival in the adult brain

To study the function of astrocytes in the adult brain, we have targeted the expression of E. coli nitroreductase (NTR) to the astrocytes of transgenic mice under the control of the GFAP promoter. The astrocytes expressing NTR were selectively ablated after administration of the prodrug CB1954, resulting in motor discoordination. Histological examination showed that the region most affected in the brain was the cerebellum, in which the Bergmann glia were eliminated and the granular neurons had degenerated. Specific effects were also noted on the dendrites of the Purkinje cells, and the junction between these neurons and granular layer was disrupted. Astrocyte ablation was associated with a dramatic decrease in the expression of glutamate transporters, which may account for the degeneration of granular neurons since the excitotoxic effects of glutamate result in a similar phenotype. These results provide the first evidence that astrocytes are important for the survival of neurons in the adult brain in vivo.

Cisplatin-induced response of c-jun N-terminal kinase 1 and extracellular signal--regulated protein kinases 1 and 2 in a series of cisplatin-resistant ovarian carcinoma cell lines

The cellular response to cisplatin involves activation of multiple signal transduction pathways, including the mitogen-activated protein (MAP) kinase pathways. In this study, we compared the cisplatin-induced activation of two MAP kinases, c-jun N-terminal kinase 1 (JNK1) and extracellular signal-regulated protein kinases 1 and 2 (ERK1/2), in the cisplatin-sensitive ovarian carcinoma cell line A2780 and its derivative cisplatin-resistant cell lines CP70 and C200. Dose-dependent and time-dependent activation of JNK1 and ERK1/2 occurred in each of the three cell lines in response to cisplatin treatment. The requirement of higher concentrations of cisplatin for induction of maximum activation of JNK1 and ERK1/2 was correlated with increased levels of cisplatin resistance. In addition, inhibition of cisplatin-induced ERK activation, using the MAP/ERK kinase 1 synthetic inhibitor PD98059, resulted in enhanced sensitivity to cisplatin in all three cell lines. These results suggest that cisplatin-induced ERK1/2 activity is not responsible for the acquired cisplatin resistance in CP70 and C200 cells but rather provides a general cytoprotective effect in both cisplatin-sensitive and cisplatin-resistant cell lines. In conclusion, different patterns of cisplatin-induced JNK1 and ERK1/2 activation are observed in cell lines with different levels of cisplatin sensitivity, and inhibition of cisplatin-induced ERK1/2 activation enhances sensitivity to cisplatin in both cisplatin-sensitive and cisplatin-resistant cell lines.

Dissecting sites important for complement regulatory activity in membrane cofactor protein (MCP; CD46)

Membrane cofactor protein (MCP; CD46), a widely distributed regulator of complement activation, is a cofactor for the factor I-mediated degradation of C3b and C4b deposited on host cells. MCP possesses four extracellular, contiguous complement control protein modules (CCPs) important for this inhibitory activity. The goal of the present study was to delineate functional sites within these modules. We employed multiple approaches including mutagenesis, epitope mapping, and comparisons to primate MCP to make the following observations. First, functional sites were located to each of the four CCPs. Second, some residues were important for both C3b and C4b interactions while others were specific for one or the other. Third, while a reduction in ligand binding was invariably accompanied by a parallel reduction in cofactor activity (CA), other mutants lost or had reduced CA but retained ligand binding. Fourth, two C4b-regulatory domains overlapped measles virus interactive regions, indicating that the hemagglutinin docks to a site important for complement inhibition. Fifth, several MCP regulatory areas corresponded to functionally critical, homologous positions in other CCP-bearing C3b/C4b-binding proteins. Based on these data and the recently derived crystal structure of repeats one and two, computer modeling was employed to predict MCP structure and examine active sites.

Disruption and functional analysis of six ORFs on chromosome XII of saccharomyces cerevisiae: YLR124w, YLR125w, YLR126c, YLR127c, YLR128w and YLR129w

In the context of the EUROFAN programme, we report the deletion and functional analysis of six open reading frames (ORFs) on the right arm of chromosome XII of Saccharomyces cerevisiae. Using a PCR-based gene replacement strategy, we have systematically deleted individual ORFs and subjected the heterozygous diploids and haploid knockout strains to basic genetic and phenotypic characterization. Two ORFs, YLR127c and YLR129w, are essential for viability, whereas no growth phenotype could be detected following deletion of YLR124w, YLR125w, YLR126c or YLR128w. For each of the individual ORFs, a kanMX4 replacement cassette and the corresponding cognate wild-type gene were cloned into appropriate plasmids.

Modified subcutaneous tissue with neovascularization is useful as the site for pancreatic islet transplantation

The success rate of subcutaneous transplantation of pancreatic islets has been extremely low. Insufficient oxygen supply to the grafted islets is one possible major obstacle to the preservation of graft function. This study attempted to use basic fibroblast growth factor (bFGF) in subcutaneous transplantation to induce neovascularization and a sufficient blood flow around the space formed for grafted islets in the subcutaneous tissues. A bFGF-releasing device was designed enclosing bFGF in a polyethylene terephthalate mesh bag coated with polyvinylalcohol hydrogel. In the vascularized group (n = 5), two bFGF-releasing devices were implanted bilaterally into the subcutaneous tissue of the back of streptozotocin-induced diabetic Lewis rats. One week after implantation, isolated rat islets (5000) were syngeneically transplanted subcutaneously after the removal of the devices. In the control group (n = 5), no devices were implanted and the same number of rat islets was transplanted directly. One week after the implantation of the devices into the test animals, a thick, well-vascularized capsule was observed in the subcutaneous site. All vascularized recipient rats showed significant decreases in nonfasting blood glucose and maintained normoglycemia for more than 1 month after islet transplantation. However, in the control group, all rats failed to achieve normoglycemia after transplantation. This study provides evidence that the subcutaneous tissue is a promising site for pancreatic islet transplantation, offering convincing advantages in acceptability for diabetic recipients. Establishment of this subcutaneous islet transplantation technique will afford some new perspectives on successful clinical islet transplantation.

Shape-selective binding of geometrically-constrained bis-distamycins to a DNA duplex and a model Okazaki fragment of identical sequence

The binding of ligands to nucleic acids is of great interest for the control of gene expression and other nucleic acid mediated processes. We have evaluated the binding of several geometrically-constrained bis-distamycins to a model Okazaki fragment [OKA], or a DNA duplex having identical base sequence [DD], using gel-shift assays, optical spectroscopy and differential scanning calorimetry. In the case of covalent attachment of two distamycins to a central benzene ring, a similar binding profile was observed for [DD] as was observed for [OKA] (para binds [K(app) > 10(6) M(-1)], meta binds only weakly). For a central pyridyl ring, however, clear distinction between the binding to [DD] and binding to [OKA] was observed. While none of the three meta isomers having a central pyridyl ring bound [OKA], two of them (MT-17 and MT-12) bound [DD] [K(app) > 10(6) M(-1)]. These results demonstrate subtle differences in lexitropsin shape and placement of electronegative atoms may result in selective binding to a nucleic acid duplex based both on base sequence and chemical composition. Selective binding to DNA duplexes may be useful for designing ligands that regulate transcription, but do not interfere in other nucleic acid mediated processes.

Differential tumor necrosis factor alpha expression and release from peritoneal mouse macrophages in vitro in response to proliferating gram-positive versus gram-negative bacteria

Viable Escherichia coli and Staphylococcus aureus bacteria elicited markedly different in vitro tumor necrosis factor alpha (TNF-alpha) responses when placed in coculture with peritoneal murine macrophages. These include quantitative differences in TNF-alpha mRNA expression and corresponding protein product secretion as well as kinetic differences in the profiles of the TNF-alpha responses. Further, lipopolysaccharide (from E. coli) is a major contributing factor to these differences, as revealed by comparative experiments with endotoxin-responsive (C3Heb/FeJ) and endotoxin-hyporesponsive (C3H/HeJ) macrophages. Nevertheless, the eventual overall magnitude of the TNF-alpha secretion of macrophages in response to S. aureus was at least equivalent to that observed with E. coli, while appearing at time periods hours later than the E. coli-elicited TNF-alpha response. Both the magnitude and kinetic profile of the TNF-alpha responses were found to be relatively independent of the rate of bacterial proliferation, at least to the extent that similar results were observed with both viable and paraformaldehyde-killed microbes. Nevertheless, S. aureus treated in culture with the carbapenem antibiotic imipenem manifests markedly altered profiles of TNF-alpha response, with the appearance of an early TNF-alpha peak not seen with viable organisms, a finding strikingly similar to that recently reported by our laboratory from in vivo studies (R. Silverstein, J. G. Wood, Q. Xue, M. Norimatsu, D. L. Horn, and D. C. Morrison, Infect. Immun. 68:2301-2308, 2000). In contrast, imipenem treatment of E. coli-cocultured macrophages does not significantly alter the observed TNF-alpha response either in vitro or in vivo. In conclusion, our data support the concept that the host inflammatory response of cultured mouse macrophages in response to viable gram-positive versus gram-negative microbes exhibits distinctive characteristics and that these distinctions are, under some conditions, altered on subsequent bacterial killing, depending on the mode of killing. Of potential importance, these distinctive in vitro TNF-alpha profiles faithfully reflect circulating levels of TNF-alpha in infected mice. These results suggest that coculture of peritoneal macrophages with viable versus antibiotic-killed bacteria and subsequent assessment of cytokine response (TNF-alpha) may be of value in clarifying, and ultimately controlling, related host inflammatory responses in septic patients.

[The epidemiological study of HIV infection among paid blood donors in one county of China]

OBJECTIVE

To observe the prevalence of HIV infection among paid blood donors and risk factors.

METHODS

Selected the residents between 18 to 50 years old from two villages in one county of China in 1997. We observed the prevalence of HIV infection and keep following them to 2000.

RESULTS

Nine hundred sixty-three residents were investigated and the prevalence of HIV was 1.8% (17/963). There were 88 paid blood donors among 963 interviewed subjects, the HIV prevalence was significantly higher (17.0% or 15/88) than those who didn't have the experiences of paid blood donations (0.2% or 2/875). Only one person out of 668 who were followed from 1997 to 2000 has converted to sero-positive, the incidence of HIV infection is 0.06 per 100 person-years. Nearly half of sero-negative and sero-positive people have the experiences of muscle injection. Among those with HIV-positive spouse, we found no one converted to sero-positive. The CD(4) count of those sero-positive people declined every year. HIV subtype and C2-V3 region sequence analysis were made for five HIV-positive people in 1998, the result indicated that all of them were infected with HIV-1 subtype B' and the genetic divergence rate was 2.4%.

CONCLUSION

There was a high prevalence of HIV among paid blood donors in some regions, and paid blood (plasma) donations were the main risk factor for HIV infection. Although no evidence suggests that during the follow-up period the epidemic of HIV infection has spread locally, it still shall take measurements to prevent further transmission of HIV through paid blood donors.

[Changes of femur minerals and serum BGP in hindlimb unloaded rats during convalescence]

Objective. To observe bone mass changes during convalescence after simulated weightlessness. Method. 7-week-old rats were tail-suspended for 21 d then reloaded for 7 d and 21 d to recover, and measured serum BGP. Result. Tail suspension of rats for 21 d caused significant decrease of serum BGP and phosphorus as well as femur minerals. Serum BGP and femur minerals were still lower than control levels, but serum contents of calcium, phosphorus and magnesium increased significantly after reloading for 7 d. Femur minerals and serum BGP, calcium, phosphorus and magnesium returned to control levels after reloading for 21 d. Conclusion. The deficit in femur mineral induced by hindlimb unloading in rats can be restored by return to normal weight bearing, BGP can be used to monitor the case of its recovery.

Discovery of High-Frequency Quasi-periodic Oscillations in the Black Hole Candidate XTE J1859+226

We report the discovery of quasi-periodic oscillations (QPOs) at roughly 187 and 150 Hz in the X-ray intensity of X-ray nova XTE J1859+226. The source was observed during a recent outburst with the Rossi X-Ray Timing Explorer. Besides these high-frequency QPOs, we have also detected QPOs (and sometimes their harmonics) at 6-7 Hz and significant broadband variability at low frequencies. These properties, as well as the observed hard X-ray spectrum, make XTE J1859+226 a black hole candidate (BHC). The detection of QPOs at two distinct frequencies greater, similar100 Hz in two observations separated by about 4 hr provide additional insights into the high-frequency QPO phenomenon in BHCs. The importance lies in the proposed interpretations, which invariably involve the effects of strong gravity near a black hole. We compare our results to those of other BHCs and discuss the impact of the observational data on the models in a global context.

2-amino-2-oxazolines as subtype selective alpha(2) adrenoceptor agonists

Cyclohexylamino oxazoline 1 (AGN 190837), an analogue of 2 (Bay a6781), is a potent alpha(2) adrenoceptor agonist. On the basis of a design generated by receptor-ligand modeling, a number of cyclohexyl and norbornyl analogues were synthesized wherein the propyl group of 1 was replaced by phenylalkyl subsituents. This resulted in compound 6 being an alpha(2c) selective agonist, as well as 7 and 9 being alpha(2a)/alpha(2c) selective.

On the Disappearance of Kilohertz Quasi-periodic Oscillations at a High Mass Accretion Rate in Low-Mass X-Ray Binaries

For all sources in which the phenomenon of kilohertz quasi-periodic oscillation (kHz QPO) is observed, the QPOs disappear abruptly when the inferred mass accretion rate exceeds a certain threshold. Although the threshold cannot at present be accurately determined (or even quantified) observationally, it is clearly higher for bright Z sources than for faint atoll sources. Here we propose that the observational manifestation of kHz QPOs requires direct interaction between the neutron star magnetosphere and the Keplerian accretion disk and that the cessation of kHz QPOs at a high accretion rate is due to the lack of such an interaction when the Keplerian disk terminates at the last stable orbit and yet the magnetosphere is pushed farther inward. The threshold is therefore dependent on the magnetic field strength-the stronger the magnetic field, the higher the threshold. This is certainly in agreement with the atoll/Z paradigm, but we argue that it is also generally true, even for individual sources within each (atoll or Z) category. For atoll sources, the kHz QPOs also seem to vanish at a low accretion rate. Perhaps the "disengagement" between the magnetosphere and the Keplerian disk also takes place under such circumstances because of, for instance, the presence of quasi-spherical advection-dominated accretion flow (ADAF) close to the neutron star. Unfortunately, in this case, the estimation of the accretion rate threshold would require a knowledge of the physical mechanisms that cause the disengagement. If the ADAF is responsible, the threshold is likely dependent on the magnetic field of the neutron star.

[Expressions of p21 and CD44v in human lung cancer and their significance.]

BACKGROUND

To investigate the clinical role of p21 and CD44v in primary lung cancer and their relationship with each other.

METHODS

p21 and CD44v expression in 29 frozen lung cancer and 10 corresponding non-cancer tissues were measured by flow cytometry (FCM) .

RESULTS

In lung cancer , the expression rates of p21 and CD44v were 75. 9 % and 51. 7 % respectively. The two proteins showed much higher FI values and positive rates in lung cancer than those in non-cancer tissues ( P < 0. 01) . p21 alteration was independent from tumor size ,lymph node metastasis , TNM stage , differentiated grade and histological type. CD44v expression in stage II+III(83. 3 %) was much higher than that in stage I(29. 4 %) ( P < 0. 01) . As compared with lung cancer without lymph node metastasis (33. 3 %) , primary lung cancer with lymph node metastasis showed significantly higher expression rate of CD44v (81. 8 %) ( P < 0. 05) . Coexpression of p21 and CD44v had a distinct statistic significance ( P < 0. 01) .

CONCLUSIONS

Abnormality of p21 and CD44v may be involved in the carcinogenesis and development of lung neoplasms in coordination. Immunopositivity of CD44v may suggest a potential of high risk for lymph node metastasis in lung cancer.

[Expression of telomerase activity in human lung cancer.]

BACKGROUND

To investigate the expression of telomerase activity in lung cancer tissue and the correlation with the oncogenesis , progression and metastasis of lung cancer.

METHODS

Telomerase activity in specimens obtained by fiberbrochoscopy from 29 patients with suspected lung cancer was detected by polymerase chain reaction-ELISA.

RESULTS

The telomerase activity was positive in 18 cases of primary lung cancer and the positive rate was 81. 81 %(18/ 22) . Two of other seven specimens were positive for telomerase activity. Twelve lung cancer cases with lymph node metastasis showed positive expression , whereas only 6 of 10 cases without lymph node metastasis showed positive expression.

CONCLUSIONS

Telomerase activity may be useful both as a diagnostic marker to detect the existence of lung cancer and as a potential of high risk for lymph node metastasis.

[CD45-gating for flow cytometric immunophenotyping of leukemia]

OBJECTIVE

To establish a reliable and rapid multiparameter flow cytometric approach for leukemia immunophenotyping.

METHODS

Leukemia blast cells which exhibit a character of low CD45 expression and low side scatter density are easily recognized by "CD45-SSC gating", we measured 46 patients and 3 normal persons of immunophenotyping by this gating method as well as traditional forwardscatter-side scatter (FSC-SSC) gating method.

RESULTS

5 of 46 immunophenotypic results from "FSC-SSC gating" showed false diagnosis, which were corrected by "CD45-SSC gating". Further, immunophenotypic mapping of 46 different acute leukemia were obtained by "CD45-SSC gating" and three-color staining, The expression of related antigen could be readily observed.

CONCLUSIONS

"CD45-SSC gating" is a reliable and easy method to subclassify leukemia. Three-color staining, which is able to analyze the expression among two related antigens, not only be helpful in leukemia diagnosis but also contribute to study the occurrence, development and prognosis of diseases.

Phase Lag and Coherence Function of X-Ray Emission from Black Hole Candidate XTE J1550-564

We report the results from measuring the phase lag and coherence function of X-ray emission from black hole candidate XTE J1550-564. These temporal X-ray properties have been recognized to be increasingly important in providing important diagnostics of the dynamics of accretion flows around black holes. For XTE J1550-564, we found significant hard lag-the X-ray variability in high-energy bands lags behind that in low-energy bands-associated both with broadband variability and quasi-periodic oscillation (QPO). However, the situation is more complicated for the QPO: while hard lag was measured for the first harmonic of the signal, the fundamental component showed significant soft lag. Such behavior is remarkably similar to what was observed of microquasar GRS 1915+105. The phase lag evolved during the initial rising phase of the 1998 outburst. The magnitude of both the soft and hard lags of the QPO increases with X-ray flux, while the Fourier spectrum of the broadband lag varies significantly in shape. The coherence function is relatively high and roughly constant at low frequencies and begins to drop almost right after the first harmonic of the QPO. It is near unity at the beginning and decreases rapidly during the rising phase. Also observed is that the more widely separated the two energy bands are, the less the coherence function between the two. It is interesting that the coherence function increases significantly at the frequencies of the QPO and its harmonics. We discuss the implications of the results on the models proposed for black hole candidates.

Glyoxal-guanine DNA adducts: detection, stability and formation in vivo from nitrosamines

The glyoxal-deoxyguanosine adduct (gG) is formed from alpha-nitrosamino aldehydes and dG in vitro and in vivo from nitrosamines carrying the 2-hydroxyethyl side-chain as well as from N-nitrosomorpholine. The structures of all of the diastereomeric forms of both the cis and trans isomers of the adduct have been investigated by ab initio calculations and with nuclear magnetic resonance spectroscopy at 500 MHz. The preferred orientation of the OH groups is trans, but at equilibrium a small amount of the cis isomer was observed. The pH-independent equilibrium constant for the hydrolysis of the gG adduct is K = 1.36 x 10(-4) mol/L, and its rate of formation at pH 7.3 is k = 5.3 min-1 mol-1. In acid (pH 2), the hydrolysis of the nucleosidic linkage is nearly twice as rapid as the hydrolysis of gG to glyoxal and dG. We used a gG analogue to explore a number of reductive methods for derivatization of the adduct, but all of the processes either gave low yields or product mixtures which rendered them impractical for derivatizing the adduct in DNA. A 32P-postlabelling method for detection of the pH-sensitive gG adduct has been developed, which permitted detection of the adduct in the liver DNA of male Wistar rats after administration of selected nitrosamines. The levels of adducts found were: N-nitrosodiethanolamine > 2-hydroxyethylmethynitrosamine > N-nitrosomorpholine > 2-hydroxyethyethylnitrosamine. In separate experiments, N-nitrosodiethanolamine gave greater adduct levels than its metabolite 2-hydroxy-N-nitrosomorpholine. Mechanistic pathways for the generation of gG adducts in vitro and in vivo are discussed.

Three-layered atmospheric structure in accretion disks around stellar-mass black holes

Modeling of the x-ray spectra of the Galactic superluminal jet sources GRS 1915+105 and GRO J1655-40 reveals a three-layered atmospheric structure in the inner region of their accretion disks. Above the cold and optically thick disk with a temperature of 0.2 to 0.5 kiloelectron volts, there is a warm layer with a temperature of 1.0 to 1.5 kiloelectron volts and an optical depth around 10. Sometimes there is also a much hotter, optically thin corona above the warm layer, with a temperature of 100 kiloelectron volts or higher and an optical depth around unity. The structural similarity between the accretion disks and the solar atmosphere suggests that similar physical processes may be operating in these different systems.

[Effects of tea on aberrant crypt foci and colorectal tumors in rats]

The present study was designed to investigate the chemopreventive effects of green tea and tea pigments (the main component of black tea) on 1,2-dimethylhydrazine (DMH)-induced rat colorectal carcinogenesis. Compared with the positive control group, green tea and tea pigments groups had less numbers of aberrant crypt foci (ACF) (P < 0.01) at the end of week 16. At the end of week 32, all rats in the positive control group developed colorectal tumors with an average of 2.6 tumors per rat, and a mean volume of 294.7 mm3 per tumor, while in the groups drinking green tea and tea pigments, the average numbers of colorectal tumors per rat were only 47.1% and 43.1% of controls respectively, and the mean tumor volume was inhibited by 77.1% and 68.1% respectively. It was concluded that tea pigments had a chemopreventive effect on colorectal tumor and ACF formation can be used as a useful intermediate end point to study chemopreventive effects on colorectal cancer.

[Establishment and biological characteristics of a novel erythroleukemia cell line (HIE1)]

OBJECTIVE

To establish a novel leukemia cell line and characterize its biological characteristics.

METHOD

The cell line was established by liquid cell culture. The genetic marker was analyzed by R-banding and reverse transcriptase-polymerase chain reaction (RT-PCR), cell morphology by microscopy, electron microscopy and histochemical staining, cell surface antigen by monoclonal antibody, hemoglobin by hyperomethemoglobin measurement and electrophoresis, erythroid differentiation by benzidine-staining, and monocyte-macrophage differentiation by cell morphology and phagocytosis.

RESULTS

A novel erythroleukemia cell line (HIE1), with original cell genetic marker (Ph chromosome, bcr/abl fusion gene rearrangement), was established from a CML patient in blast crisis, and has been passaged for over 60 generations. Myelomonocyte marker and hemoglycoprotein A were found on the cell surface. HIE1 cells contained hemoglobin, the same HbA and HbA(2) bands as in normal individuals were displayed by Hb electrophoresis. The benzidine positive HIE1 cells were induced after exposure to 3.6 x 10(-4) mmol/L Ara-C. When HIE1 cells were treated with 100 ng/ml PMA for 3 days, one third of the cells became spindle in shape, and 6.5% of the cells exert phagocytosis. The cells were classified into two types with Wright-staining: one showing light blue cytoplasm and a few of cells with basophilic granules, the other showing dark blue cytoplasm with vacuoles and pseudopods without granules. In addition, POX, SB, CE stains were negative, and AE, PAS, ACP stains positive. Colony formation of the cells was 37%, the cell doubling time was 22 - 24 hrs, and EB virus detection was positive.

CONCLUSION

A novel erythroleukemia cell line with bcr/abl fusion gene and characteristics of myelomonocytic and erythroid cells was established.

Presenilin-1 forms complexes with the cadherin/catenin cell-cell adhesion system and is recruited to intercellular and synaptic contacts

In MDCK cells, presenilin-1 (PS1) accumulates at intercellular contacts where it colocalizes with components of the cadherin-based adherens junctions. PS1 fragments form complexes with E-cadherin, beta-catenin, and alpha-catenin, all components of adherens junctions. In confluent MDCK cells, PS1 forms complexes with cell surface E-cadherin; disruption of Ca(2+)-dependent cell-cell contacts reduces surface PS1 and the levels of PS1-E-cadherin complexes. PS1 overexpression in human kidney cells enhances cell-cell adhesion. Together, these data show that PS1 incorporates into the cadherin/catenin adhesion system and regulates cell-cell adhesion. PS1 concentrates at intercellular contacts in epithelial tissue; in brain, it forms complexes with both E- and N-cadherin and concentrates at synaptic adhesions. That PS1 is a constituent of the cadherin/catenin complex makes that complex a potential target for PS1 FAD mutations.

Shape-selective recognition of a model Okazaki fragment by geometrically-constrained bis-distamycins

Okazaki fragments represent interesting targets for the design of anticancer drugs because of their selective occurrence during DNA replication, a process often elevated in aggressive malignancies. Structural studies have indicated a bend occurs in the helical axis at the junction region (JR) that joins the DNA duplex region (DDR) and the RNA-DNA hybrid duplex region (HDR) of model Okazaki fragments. To identify a structural motif that provides a shape complementary to the Okazaki fragment minor groove, we have investigated the binding of geometrically-constrained bis-distamycins to a model Okazaki fragment, [OKA], with a sequence derived from the genome of simian virus 40 (SV40). Both the JR and the DDR of [OKA] contain consecutive A/T base pairs that could accommodate distamycin binding. Of the six bis-distamycins selected for analysis, the two with a para configuration of the distamycins on the benzene or pyridine scaffold bound [OKA] tightly (Kd approximately 10(-6) M from gel-shift assays; Kd approximately 10(-8) M from deltaT(M)) while the four with a meta orientation did not bind. The two mono-distamycins studied also did not bind [OKA]. Molecular modeling of the complex between the para bis-distamycin MT-9 and [OKA] revealed MT-9 adopted an S- shape complementary to the minor groove of the model Okazaki fragment.

[Preventive effect of vitamin K1 and calcium on osteoporosis in ovariectomized rat]

Ovariectomized female Wistar rats[(170 +/- 15) g] were treated with vitamin K1 or/and calcium for 6 months, in order to study the effect of vitamin K or/and calcium supplementation on the prevention of osteoporosis. Vitamin K1(90 mg/kg) or/and calcium(5 g/kg) were added to a semisynthetic basal diet (VK 50 micrograms/kg, Ca5 g/kg). The findings of the study were as follows: Vitamin K1 treatment led to a significant increase of bone mineral density of the femoral diaphysis and lumbar spine, and bone ash content of the proximal one third of the femur shaft. The results suggested that vitamin K1 could, to some extent, prevent the fast bone loss and the femoral fragility induced by ovariectomy. Regarding the parameters of bone metrology and biomechanics, the effect of vitamin K1 combined with calcium on the prevention of osteoporosis is better than that of vitamin K1 or calcium alone, and the treatments with VK and Ca had better effects on femur than lumbar spine. The present study indicates that for postmenopausal women, as a risk population of osteoporosis, to increase their dietary intake of vitamin K and calcium might be helpful.

[Changes of blood circulation, muscle and skeletal systems in 30 d tail-suspended [correction of tail-suspented] rats]

OBJECTIVE

To confirm the tail-suspended rat model for the study of countermeasures against weightlessness.

METHOD

The changes of blood circulation, muscle and skeletal systems in control group rats (n = 15) and 30 d tail-suspended rats (n = 15) were compared.

RESULT

Compared with the control group, the hemorrheology and erythrocyte deformability decreased significantly, muscle-fiber atrophy, muscle contraction function decreased, the type I muscle fibers transformed to the type II muscle fibers, bone-mineral content of L3 and load capacity of femur declined, bone metabolism changed in the suspended rats.

CONCLUSION

The tail-suspended rat is a suitable animal model for the study of countermeasures against weightlessness.

Novel method for isolation of adult porcine pancreatic islets with two-stage digestion procedure

It is particularly difficult to isolate porcine islets (PI). Experience suggests that the success rate of porcine islet isolation (PII) is probably considerably influenced by the distension and digestion of the pancreas. In this study, we divided the digestion procedure into two stages and developed a new enzyme solution to improve both the distension and digestion procedures. As a result, we established a novel and stable method of large-scale adult porcine islet isolation (APII). The harvested pancreata of 2-year-old pigs weighing over 200 kg (n = 18) were distended by introducing our new enzyme solution gently and slowly through the pancreatic ducts. Two-stage digestion (cold, then warm) was then performed by first placing the distended pancreata on ice for 2 h to cause diffusion of the enzyme solution around the islets, and then by incubating the pancreata in a water bath at 37 degrees C for 45 min without shaking. The islets were purified by a COBE 2991 cell processor on dextran T70 discontinuous density gradients. Histological study was performed on porcine pancreata sampled after 0, 15, 30, and 45 min of the second stage, and stained with H&E stain. Next, islet equivalent was calculated. Static incubation study was performed by stimulating the islets with 3.3 and 16.7 mM glucose in Krebs' Ringer bicarbonate buffer (KRBB) solution at 37 degrees C for 1 h, and finally the insulin released was measured. The dilated acinar cells septa around the islets were observed at time 0. Destruction of the acinar cells around the islets by warm digestion was recognized at 15 and 30 min, and destroyed and separated acinar cells present around the islets at 45 min. During the entire course of the warm digestion, the islets remained intact. The number of isolated islets was 291,667 +/- 240,452 IEQ/pancreas (n = 14) and 3,294 +/- 2199 IEQ/g of pancreatic tissue. The purity of recovered porcine islets was over 90%. The concentration of the insulin secreted by 10,000 IEQ islets selected at random was 83.9 +/- 13.4 microU/dish/h in response to 3.3 mM glucose and 104.1 +/- 12.9 microU/dish/h in response to 16.7 mM glucose (n = 20). A success rate of approximately 80% was attained with APII. We demonstrated that this increase in the success rate was due to the improved distension and digestion provided by this method. This two-stage APII method with its new enzyme solution may facilitate the future use of porcine islets in clinical xenotransplantation trials.

[The Raman spectra of rubidium titanyl arsenate]

The Raman spectra of rubidium titanyl arsenate (RTA) single crystal with different geometric arrangements were obtained and compared with those of rubidium titanyl phosphate (RTP), potassium titanyl arsenate (KTA) and potassium titanyl phosphate (KTP) single crystals. The assignments of various vibration modes were made according to the experimental results. The strong Raman scattering intensity implies that RTA crystal possesses large nonlinear optical property and the strongest scattering is from the TiO6 octahedron. From the mode splitting of AsO4 tetrahedron, we conclude that the distortion of AsO4 in RTA is larger than that of PO4 in KTP.

No metal cofactor in orotidine 5'-monophosphate decarboxylase

Orotidine 5'-monophosphate decarboxylase (OMP decarboxylase, ODCase) is an important enzyme that catalyzes the final step of de novo pyrimidine nucleotide biosynthesis. The mechanism of this unique enzyme and whether metal ions play any role in catalysis have been topics of intense research interest. In this report, the role of Zn in ODCase was reexamined. Atomic absorption (AA) and X-ray absorption (XAS) spectroscopic studies did not detect zinc in active enzyme samples at high concentration. The XAS results also indicated the absence of other transition metal ions in ODCase.

Cisplatin-induced activation of mitogen-activated protein kinases in ovarian carcinoma cells: inhibition of extracellular signal-regulated kinase activity increases sensitivity to cisplatin

Cisplatin treatment activates multiple signal transduction pathways, which can lead to several cellular responses including cell cycle arrest, DNA repair, survival, or apoptosis. We investigated the response of the mitogen-activated protein kinases, extracellular signal-regulated kinases 1 and 2 (ERK1/2), c-Jun-N-terminal kinase 1 (JNK1), and p38, to cisplatin treatment in the ovarian carcinoma cell line SK-OV-3. Cisplatin caused a late and prolonged induction in a dose-dependent manner of both ERK1/2 and JNK1 activity. ERK1/2 and JNK1 activities continued to increase in magnitude up to 24 h following initiation of cisplatin treatment. In contrast, cisplatin treatment had no effect on p38 activity. Transplatin failed to induce either ERK1/2 or JNK1 at 24 h, which suggests that the activation of these kinases was dependent on cisplatin-specific DNA damage. Treatment with cycloheximide resulted in inhibition of cisplatin-induced ERK1/2 activation, demonstrating that ERK1/2 activity induced by cisplatin was dependent on de novo protein synthesis. Furthermore, inhibition of cisplatin-induced ERK1/2 activity by PD 98059 caused enhanced cisplatin cytotoxicity. Similar enhanced cytotoxic effects of cisplatin were also observed following treatment with PD 98059 in the ovarian carcinoma cell line UCI 101. These observations indicate that ERK1/2 activation induced by cisplatin partially protects cells from cisplatin cytotoxicity. Continued investigation into the mechanism by which the ERK pathway and other signal transduction pathways modulate the response to cisplatin may be helpful in the development of new strategies for improving the therapeutic use of platinum drugs.

[Serum levels of soluble intercellular adhesion molecule 1 in malignant lymphoproliferative disorders]

OBJECTIVE

To investigate the correlation of serum levels of soluble intercellular adhesion molecule 1 (sICAM-1) with clinical situation and treatment outcome in lymphoproliferative disorders.

METHODS

Serum sICAM-1 levels were measured by immunoenzymatic assay.

RESULTS

Pre-treatment serum sICAM-1 levels were above normal in 41% (9/22) of multiple myeloma (MM), 53% (17/32) of non-Hodgkin's lymphoma (NHL) and 63% (12/19) of acute lymphocytic leukemia (ALL) patients. Serum sICAM-1 levels in MM were positively correlated with Bataille stages, but were not related to Durie stage. Meanwhile, sICAM-1 levels in NHL were associated with the category of pathology, Ann Arbor stage and B symptom, but were not related to serum LDH levels. sICAM-1 levels were significantly higher in ALL patients complicated with central nervous system leukemia (CNSL) than in those without CNSL. Patients with elevated serum sICAM-1 levels had poorer treatment outcomes. Serum sICAM-1 levels were returned to normal at remission.

CONCLUSION

Measurement of serum sICAM-1 levels in lymphoproliferative disorders patients is helpful for judging the clinical status and treatment outcome.

Nitroreductase-mediated cell ablation is very rapid and mediated by a p53-independent apoptotic pathway

Nitroreductase (NTR)-mediated selective cell ablation using the prodrug CB1954 has been achieved in vivo by targeting the nitroreductase gene to the luminal cells of the mammary gland in transgenic mice. We report that the cell ablation occurs very rapidly, starting as early as 7 h after administration of the prodrug. By cross-breeding the BLG-NTR transgenic mice to a p53-deficient mouse strain, we have generated BLG-NTR transgenic mice on a p53 null background and tested NTR-mediated cell ablation in these mice. The transgenic mice lacking a functional p53 gene showed cell ablation at a similar level compared with p53 wild-type transgenic mice, showing that functional p53 is not required for CB1954-NTR mediated cell death. These results provide further support for using this system in anti-cancer therapy.

A novel follicle-cell-dependent dominant female sterile allele, StarKojak, alters receptor tyrosine kinase signaling in Drosophila

We describe a new dominant allele, StarKojak, that alters receptor tyrosine kinase signaling in the follicle cells and in the eyes in Drosophila. We isolated StarKojak in a screen for follicle-cell-dependent dominant female sterile mutations. We show that StarKojak and revertants of StarKojak do not complement Star loss-of-function mutations. We propose that StarKojak is a novel type of allele of Star that has both dominant gain-of-function phenotypes early in development and dominant loss-of-function phenotypes later in development. Star encodes a putative transmembrane protein that has previously been shown to be a critical component of the epidermal growth factor receptor tyrosine kinase signaling pathway. Early in oogenesis, Star mRNA expression is higher in StarKojak egg chambers than in wild-type egg chambers, consistent with its gain-of-function phenotype. Later in oogenesis, Star mRNA expression is lower in StarKojak follicle cells than in wild-type follicle cells, consistent with its loss-of-function phenotype. By genetically analyzing StarKojak and its revertants, we present evidence that Star is involved in anterior-posterior axis formation both in the female germline cells and in the somatic follicle cells. We also demonstrate that at least part of the dominant female sterile phenotype of StarKojak is restricted to the posterior-pole follicle cells. We propose that Star functions by processing pro-Gurken to mature Gurken, which is thereby released in the region between the oocyte and the follicle cells and binds to the epidermal growth factor receptor in the follicle cells.