Chemical constituents of the leaves of Diospyros kaki and their cytotoxic effects

Isolation and structure elucidation of two new compounds, kakispyrone (1) and kakisaponin A (2), together with 11 known compounds, from the leaves of Diospyros kaki L. are described. Their cytotoxic effects against several cancer cell lines (A549, HepG2 and HT29) are also reported.

Effect of placement of calcium sulphate when used for the repair of furcation perforations on the seal produced by a resin-based material

AIM

To evaluate the sealing ability of calcium sulphate when used under composite resin for the repair of furcation perforations having different diameters.

METHODOLOGY

Perforations of different diameter were created in the floors of pulp chambers in 60 extracted human molar teeth with either a number 3 (1 mm diameter) or 5 (1.5 mm diameter) round bur. The specimens of each group were divided into four sub-groups which were repaired with composite resin either alone or in combination with calcium sulphate that created an artificial floor (15 teeth group(-1)). Eight teeth without furcation perforations served as negative controls. In the leakage detection device, 1 mol L(-1) glucose solution was forced under a pressure of 1.5 KPa from the crown towards the pulp chamber floor. The concentration of leaked glucose was measured at 1, 2, 4, 7, 10, 15 and 20 days using a glucose oxidase method and the data evaluated using the rank sum test.

RESULTS

The specimens with larger perforations repaired with composite resin alone had significantly more leakage (P < 0.05). Using calcium sulphate as an artificial floor significantly decreased leakage of smaller perforations (P < 0.05). In groups repaired with calcium sulphate under composite resin, leakage in smaller perforations was markedly lower than that in larger ones (P < 0.05). No significant difference was found between the specimens with 1 or 1.5 mm perforations repaired with resin alone (P > 0.05).

CONCLUSIONS

Calcium sulphate significantly improved the sealing ability of 1 mm perforations repaired with composite resin but not for 1.5 mm perforations.

Layer thickness and curvature effects on otoconial membrane deformation in the utricle of the red-ear slider turtle: static and modal analysis

Finite element models of otoconial membrane (OM) were developed to investigate the effects of three geometric variables on static and modal response of the OM: (1) curvature of the macular surface, (2) spatial variation in thicknesses of three OM layers, and (3) shape of the macular perimeter. A geometrically accurate model of a turtle utricle was constructed from confocal images. Modifying values for each variable formed variants of this model: modeling the macula surface as flat, OM layer thicknesses as spatially invariant, and the macular perimeter as a rectangle. Static tests were performed on each modified OM model, and the results were compared to determine the effects of each geometric variable on static mechanical gain (deflection per unit acceleration). Results indicate that all three geometric variables affect the magnitude and directional properties of OM static mechanical gain. In addition, through modal analysis, we determined the natural frequencies and displacement modes of each model, which illustrate the effects of the three geometric variables on OM dynamics. This study indicates the importance of considering three-dimensional OM geometry when attempting to understand responses of the OM and, therefore, the modulation of hair cell signals to accelerations during head movements.

Gain of 1q25–32, 12q23–24.3, and 17q12–22 facilitates tumorigenesis and progression of human squamous cell lung cancer

To explore the genetic changes involved in the stepwise development of lung cancer, we have determined the genetic events associated with the histological progression from normal bronchial epithelium to squamous cell carcinoma. Comparative genomic hybridization was used to identify chromosomal imbalances in 54 microdissected samples, including squamous metaplasia, dysplasia, carcinoma in situ, and invasive tumour derived from 23 patients with squamous cell carcinoma of the lung. Histopathological progression was accompanied by an increased number of chromosomal abnormalities. Gains of 1q25-32, 12q23-24.3, and 17q12-22, in particular, were detected at high frequencies in both carcinoma in situ and invasive tumours and were found more often in the cases with lymph node metastases than in those without. Our previous expression profiling of squamous cell carcinomas had identified overexpression of laminin5 gamma2, a gene located at 1q25-31. Therefore, this was investigated at the protein level by immunohistochemical analysis in 336 samples of squamous cell carcinoma of the lung. Consistent with the genomic data for this region, the expression level of laminin5 gamma2 was higher in the primary tumours with lymph node metastases than in tumours without metastases (p = 0.012). These data suggest that gains of genes from 1q25-32, 12q23-24.3, and 17q12-22 facilitate tumorigenesis and progression of squamous cell carcinoma of the lung, and may serve as potential predictors for this disease.

Electrolytic degradation of biorefractory organics and ammonia in leachate from bioreactor landfill

Electrochemical oxidation was applied to treat the effluent from bioreactor landfill with leachate recirculation, characterised as poor biodegradability and high NH3-N concentration. In this study, the effluent was electrolysed in a batch reactor with Ti/TiO2-IrO2-RuO2 anode and stainless steel cathode. The oxidation of dissolved organic matter (DOM) during electrolysis was evaluated based on the evolution of molecular weight grade, hydrophilic fractionation (humic acid, fulvic acid and hydrophilic fractions), specific ultraviolet absorbance (SUVA254) and AOX. The impact of the initial NH3-N concentration on the oxidation was discussed. The results showed that at a current density of 100 mA/cm2, electrolysis time of 1.5 h and electrode gap of 1 cm, NH3-N with an initial concentration of 1.2 g/L could be completely eliminated and 56% of COD with an initial concentration of 1.2 g/L could be removed, which illustrated that the electrolysis-produced chlorine preferentially oxidised ammonia. The electrolysis mainly resulted in the degradation of humic substances and other high molecular DOM, followed by the increase of BOD/COD ratio and decline of SUVA254 of the leachate. The current efficiencies for COD and ammonia oxidation gradually decreased during the electrolysis, with the latter obviously higher than the former. At the optimal electrolysis time of 1.5 h, NH3-N could be totally removed and the BOD/COD ratio could be enhanced to 0.3, which was also favourable to control the AOX at a reasonable level.

119 THE LOCALIZATION OF A METHYL BINDING DOMAIN PROTEIN (MBD4) IN MURINE AND BOVINE OOCYTES AND PRE-IMPLANTATION EMBRYOS

The presence of MBD4, a member of the methyl binding domain family, was investigated in both murine and bovine oocytes and pre-implantation embryos. MBD4 is the only MBD family member that is involved in DNA repair but not active in transcriptional repression or in the formation of complexes with histone deacetylase complexes (HDACs). It contains a mismatch-specific glycosylase domain that acts to repair G:T mismatches within a CpG context. Bovine cumulus oocyte complexes were collected from abattoir-derived ovaries, matured in vitro and used for IVF as described previously (Ruddock et al. 2004 Biol. Reprod. 70, 1131–1135). Samples were analyzed at all steps in this process. Murine oocytes were collected from superovulated mice (C57BL6 × CBA) and subjected to conventional IVF. A polyclonal antibody derived in the rabbit against human peptides from specific regions of MBD4 (Imgenex, San Diego, CA, USA) was used to localize MBD4 protein. This antibody was tested at a variety of concentrations against both human HL60 leukemia cells and bovine embryos. Staining of HL60 cells was optimum at 32–64 μg/mL and embryos at 64 μg/mL. Briefly, the staining protocol consisted of fixing cells and zona-free oocytes or embryos in 4% paraformaldehyde for 15 min, followed by 15 min in 0.1% Triton X-100. Primary antibody incubation was performed overnight at 4°C. Embryos were then washed in blocking buffer for 1 hr prior to incubation at 4°C in mouse anti-rabbit IgG conjugated to FITC in blocking buffer for 30 min in the dark. Lastly, embryos were incubated in 10 μg/L Hoescht 33342 for 15 min, and then washed and mounted with Vectashield (Vector Labs, Burlingame, CA, USA). Negative controls contained no primary antibody. Mounted cells/embryos were viewed by epifluorescence microscopy. MBD4 was found to be expressed in both murine and bovine oocytes and pre-implantation embryos. In the cow, faint nuclear expression was detected at the 2-cell stage, followed by exclusion of the protein from the nucleus until the blastocyst stage of development. At this stage, staining was primarily nuclear and quite intense. In the mouse, staining was cytoplasmic at the 2 pronuclear stage, but was then concentrated in the nucleus from the 2-cell stage onward. It will be interesting to determine if this is due to the different timing of embryonic genome activation between the two species, hence implying a role for MBD4 in this important biological process. Further investigations are underway to compare the subcellular localization of the other MBD proteins in both species during preimplantation development and to identify a role for MBD4 in embryonic genome activation.

Expression of Na+/H+ and HCO3−-dependent transporters in Na+/H+ exchanger isoform 1 null mutant mouse brain

Acid-base transporters, such as the sodium-hydrogen exchangers (NHEs) and bicarbonate-dependent transporters, play an important role in the regulation of intracellular pH (pH(i)) in the CNS. Previous studies from our laboratory have shown that the absence of the major NHE isoform 1 (NHE1) reduced the steady-state pH(i) and recovery rate from an acid load in the hippocampal neurons not only in HEPES but also in HCO(3)(-) solutions (Yao et al., 1999). The purpose of the current study was to determine whether the NHE1 null mutation affects the expression of pH-regulatory transporters in the mouse CNS. Immunoblotting and semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) were performed to examine the protein and mRNA levels of NHE1-4, electrogenic sodium-bicarbonate cotransporter 1 variants (NBCe1), and brain-specific anion exchanger 3 (AE3) in four brain regions (cerebral cortex, hippocampus, cerebellum and brainstem-diencephalon). NHE1 null mutant mice were compared with their wild type controls at the average age of approximately 4 weeks. Our results revealed that the NHE1 null mutation caused a significant increase in NHE3 in the cerebellum (84% for protein, 105% for mRNA), an increase in NBCe1 expression in the brainstem-diencephalon (approximately 40-50% for protein, 9-15% for mRNA), as well as a decrease in AE3 in the hippocampus (approximately 60% for protein, 24% for mRNA). We conclude that the NHE1 null mutation does alter the expression of other membrane transporters at both protein and mRNA levels. The alteration is region-specific. An increase in acid extruders (e.g. NHE3) and a decrease in acid loaders (e.g. AE3) suggest that there are some compensatory mechanisms that occur in NHE1 null mutant mice.

The effect of astragapolysaccharide on the lymphocyte proliferation and airway inflammation in sensitized mice

In order to investigate the regulating role of Astragapolysaccharide (APS) in the mice model of asthmatic airway inflammation, the airway eosinophil number, spleen T lymphocyte proliferation, level of IL-2 production and their relationships were studied in sensitized mice and sensitized mice treated with different concentrations of APS. The results showed that the number of eosinophils as well as lymphocytes in the airway of the sensitized animals were significantly increased, and a marked positive correlation between the inflammation cells and spleen T lymphocyte proliferation was found. Moreover, there was a positive correlation between inflammation cells and the level of IL-2 production. The APS of given dosage could significantly reduce the number of eosinophils in the airway of the sensitized animals. At the same time the level of IL-2 secreted by spleen T lymphocytes stimulated with ConA was also significantly decreased and there was a marked positive correlation between them. Our results suggested that APS of given dosage could prevent antigen-induced the number of eosinophils infiltrating into the airway of sensitized mice and inhibit the proliferation and activation of lymphocyte and IL-2 production. Through its immuno-regulating effect, APS can be helpful in the treatment of asthma.

Chronic intermittent hypoxia decreases the expression of Na/H exchangers and HCO3-dependent transporters in mouse CNS

Chronic intermittent hypoxia (CIH) is a component of several disease states, including obstructive sleep apnea, which results in neurocognitive and cardiovascular morbidity. Because chronic hypoxia can induce changes in metabolism and pH homeostasis, we hypothesized that CIH induces changes in the expression of acid-base transporters. Two- to three-day-old mice, exposed to alternating cycles of 2 min of hypoxia (6.0-7.5% O2) and 3 min of normoxia (21% O2) for 8 h/day for 28 days, demonstrated decreases in specific acid-base transport protein expression in most of the central nervous system (CNS). Sodium/hydrogen exchanger isoform 1 (NHE1) and sodium-bicarbonate cotransporter expression were decreased in all regions of the CNS but especially so in the cerebellum. NHE3, which is only expressed in the cerebellum, was also significantly decreased. Anion exchanger 3 protein was decreased in most brain regions, with the decrease being substantial in the hippocampus. These results indicate that CIH induces downregulation of the major acid-extruding transport proteins, NHE1 and sodium-bicarbonate cotransporter, in particular regions of the CNS. This downregulation in acid-extruding capacity may render neurons more prone to acidity and possibly to injury during CIH, especially in the cerebellum and hippocampus. Alternatively, it is possible that O2 consumption in these regions is decreased after CIH, with consequential downregulation in the expression of certain cellular proteins that may be less needed under such circumstances.

Accurate bounds for the asymptotic constant in a statistical multiplexer with homogeneous generalized binary Markov sources

This paper considers the asymptotic tail distribution of the number of cells queued in a statistical multiplexer fed with homogeneous generalized binary Markov sources. As the asymptotic decay rate is easy to obtain, we focus our effort on bounding the asymptotic constant, which is dependent on the initial phase combination of the sources and is hard to compute even for a moderate number of sources. We derive upper and lower bounds for the asymptotic constant, taking the initial phase combination into account. Numerical experiments show the accuracy of these bounds. They also show that, while the asymptotic decay rates are the same, the variation of initial phase combination of the sources may significantly affect the asymptotic constants.

A new method to incorporate age and gender into the criteria for the detection of acute inferior myocardial infarction

Recent studies have shown that younger women are more likely to die during and after hospitalization for acute myocardial infarction (MI) than older women and men of all ages. This may be partly due to incorrect diagnosis or late detection of acute MI in younger women. At high specificity levels (>98%), the sensitivity of the initial ECG to detect acute MI may be as low as 30% when using traditional criteria by both physicians and computerized interpretation programs. This study examines if women of different age groups have a similar ECG presentation to men during acute inferior MI and if the diagnostic accuracies of the initial ECG are comparable. We analyzed chest pain ECGs from Mayo Clinic and Medical College of Wisconsin, which included 1,339 patients with acute inferior MI and 1,169 age-matched controls with noncardiac chest pain. We subdivided all groups by age (below and above 60 years) and compared ECG parameters (ST elevation, ST depression, QRS duration, R-wave amplitude, Q-wave duration and amplitude, QT interval) between genders. For inferior MI patients under age 60, women had lower ST elevations at the J point in lead II than men (57 +/- 91 microV vs. 86 +/- 117 microV, P < .02). This trend was reversed for patients over age 60 (lead a VF: 102 +/- 126 microV vs. 84+/-117 microV, P < .04; Lead III: 130+/-146 microV vs. 103+/-131 microV, P < .007). A neural network method was used to identify the most significant group of ECG parameters for detecting acute MI. An adaptive fuzzy logic method was developed for adapting to the threshold differences among the different gender and age groups. The new algorithm improved the sensitivity of acute inferior MI detection by more than 25% relative to old algorithm, while maintaining the high specificity around 98% for noncardiac chest pain patients.

[The transfer and expression of human clotting factor IX in muscle mediated by electroporation]

OBJECTIVE

To probe into the feasibility of increasing hFIX cDNA transfer and expression in muscle.

METHODS

The high-frequency electric field was used to promote both Lac-Z-encoding plasmid pCMV beta and hFIX-expressing plasmid G1NaMCIX to transfer and express in muscle. The effects of frequency and length of square pulse, as well as eletroporation time on hFIX expression were investigated.

RESULTS

Electric stimulation could increase the transfer and expression of pCMV beta in muscle, the number of X-gal positive myofiber cells in electroporation-treated mice is 2.1 times larger than that of mice not treated by electroporation (P<0.01). The most optimal electric simulation condition for hFIX cDNA transfer and expression was obtained, under this condition, the highest level of hFIX antigen in plasma is (40+/- 5.4) ng/ml and 7 times higher than that of mice without electroporation P < 0.001).

CONCLUSION

Electroporation is able to enhance hFIX cDNA transfer and expression in muscle efficiently.

Differential gene expression of adenosine A1, A2a, A2b, and A3 receptors in the human enteric nervous system

Adenosine receptors (ADORs) in the enteric nervous system may be of importance in the control of motor and secretomotor functions. Gene expression and distribution of neural adenosine A1, A2a, A2b, or A3 receptors (Rs) in the human intestine was investigated using immunochemical, Western blotting, RT-PCR, and short-circuit current (I(sc)) studies. Adenosine A1R, A2aR, A2bR, or A3R mRNAs were differentially expressed in neural and nonneural layers of the jejunum, ileum, colon, and cecum and in HT-29, T-84, T98G, and Bon cell lines. A1R, A2aR, A2bR, and A3R immunoreactivities (IRs) were differentially expressed in PGP 9.5-immunoreactive neurons. A2bR IR occurs exclusively in 50% of submucosal vasoactive intestinal peptide (VIP) neurons (interneurons, secretomotor or motor neurons) in jejunum, but not colon; A2aR is also found in other neurons. A3R IR occurs in 57% of substance P-positive jejunal submucosal neurons (putative intrinsic primary afferent neurons) and less than 10% of VIP neurons. Western blots revealed bands for A3R at 44 kDa, 52 kDa, and 66 kDa. A2aR and A2bR are coexpressed in enteric neurons and epithelial cells. 5'-N-methylcarboxamidoadenosine or carbachol evoked an increase in I(sc). A2bR IR is more prominent than A2aR IR in myenteric neurons, nerve fibers, or glia. A1R is expressed in jejunal myenteric neurons and colonic submucosal neurons. Regional differences also exist in smooth muscle expression of ADOR IR(s). It is concluded that neural and nonneural A1, A2a, A2b, and A3Rs may participate in the regulation of neural reflexes in the human gut. Clear cell and regional differences exist in ADOR gene expression, distribution, localization, and coexpression.

Visual-mediated regulation of retinal CaMKII and its GluR1 substrate is age-dependent

Previous studies have shown that multifunctional calcium/calmodulin-dependent protein kinase II (CaMKII) and one of its substrates, the glutamate receptor, are key players in experience-driven synaptic plasticity in several areas of the central nervous system (CNS). To determine if CaMKII and the glutamate receptor are regulated by visual activity in the retina, we compared dark-reared (DR; 1 week) rats with control rats raised in a diurnal light-dark cycle (LD), at the following ages: postnatal day 12 (P12d), 2-month (2m) and 6-month (6m) old. The mRNA levels of CaMKIIalpha and beta were determined by a competitive reverse transcription polymerase chain reaction (competitive RT-PCR) method. The protein levels of these two subunits were evaluated by immunoblots. The data show that the mRNAs for CaMKIIalpha and beta were increased about 8-fold and 10-fold, respectively, in the retinae of DR P12d rats. As for the proteins, 2- and 2.6-fold elevations for CaMKIIalpha and beta, respectively, were evident. The GluR1 subunit of the AMPAR (AMPAR-GluR1) was also evaluated in antibody-treated blots and found to be increased about 2-fold after 1 week of dark rearing in the retinae of P12d rats. This type of experience-driven molecular change was age-dependent, showing less increase in 2m old rats and not present in 6m old rats. Returning DR 2m old rats to the LD environment for 1 week was sufficient to restore the dark-induced changes to the levels of the age-matched LD controls. Based on the data, a theoretical model for activity-dependent modulation of the developing retinal synapses is proposed.

Testicular protein Spag5 has similarity to mitotic spindle protein Deepest and binds outer dense fiber protein Odf1

Outer dense fibers (ODF) and the fibrous sheath (FS) are major cytoskeletal structures in the mammalian sperm tail. The molecular mechanisms underlying their morphogenesis along the axoneme or their function are poorly understood. Recently, we reported the cloning and characterization of Odf2, a major ODF protein, and Spag4, an axoneme-binding protein, by virtue of their strong interaction with Odf1, the 27 kDa major ODF protein. We proposed a crucial role for leucine zippers in molecular interactions during sperm tail morphogenesis. Here we report the cloning and characterization of a novel gene, Spag5, which encodes a 200 kDa testicular protein that interacts strongly with Odf1. Spag5 is transcribed and translated in pachytene spermatocytes and spermatids. It bears 73% similarity with the mitotic spindle protein Deepest of unknown function. We identified two putative leucine zippers in the C-terminal part of the Spag5 protein, the downstream one of which is involved in interaction with Odf1. Interestingly, these motifs are present in Deepest. These results highlight the importance of the leucine zipper in sperm tail protein interactions. Mol. Reprod. Dev. 59: 410-416, 2001.

Study of an Au colloid self-assembled electrode and its application to the determination of carbon monoxide

A novel electrochemical sensor has been developed for the detection of carbon monoxide. The chemically modified electrode, prepared by reaction of cysteine and then an Au colloid of size approximately 15 nm with a platinum microelectrode, has excellent catalytic activity toward carbon monoxide, with an oxidation potential of +600 mV relative to the Ag/AgCl electrode. The CO gas sensor is based on an Au colloid self-assembled modified electrode as working electrode, an Ag/AgCl electrode as reference electrode, a Pt electrode as counter electrode, and a porous film which is in direct contact with the gas-containing atmosphere. The effects on the determination of CO of different internal electrolyte solutions of perchloric acid, hydrochloric acid, sulfuric acid, nitric acid, and phosphate buffer of different concentrations were also studied. The sensor is characterized by a short response time and highly reproducible detection of CO. This sensor can be used in the field of environmental monitoring and control.

The modification of NMDA receptors by visual experience in the rat retina is age dependent

Extensive studies have shown that the activation of N-methyl-D-aspartate receptors (NMDARs) and the subsequent rise in the levels of postsynaptic calcium are critical events in the initiation of synaptic plasticity. Modification of the amount, or of the subunit composition of NMDARs, alters receptor function thereby affecting the development and/or efficacy of synaptic transmission. In the present study, a Western blot analysis was employed to investigate the effects of visual experience and age on the differential expression of NMDARs in the rat retina. A crude synaptic membrane fraction (SPM) was prepared and assayed with antibodies specific for either the NR1, NR2A or NR2B subunits. Relative to control animals raised in a diurnal light-dark cycle, a period of 1 week of dark-rearing caused an increase in the relative amount of NR1, a decrease in the level of NR2A, and no change in the level of NR2B subunit expression in postnatal day 12 rats. At 2 months of age, 1 week of dark-rearing had less effect, and at 6 months of age there was no difference between dark-reared and control animals. The effect of light exposure on dark-reared animals was tested for the 2-month-old animals. Light exposure for long periods (days), but not short periods (h), could reverse the dark-rearing effects. These data provide evidence for a developmentally regulated plasticity of NMDAR subunits in the retina.

Gelatinase A (MMP-2) in developing tooth tissues and amelogenin hydrolysis

Matrix metalloproteinases (MMPs) are thought to play important roles during enamel and dentin biomineralization. Previously, membrane type-1 matrix metalloproteinase (MT1-MMP) was localized to the plasma membranes of ameloblasts and odontoblasts of the developing tooth. The best-characterized function of MT1-MMP is to initiate the activation of gelatinase A (MMP-2). Thus, we hypothesized that gelatinase A may also be expressed by developing tooth tissues. A full-length porcine gelatinase A mRNA was isolated by RT-PCR homology cloning of an enamel-organ-specific cDNA library. Northern blot and in situ hybridization analyses demonstrated gelatinase A expression in developing tooth tissues. Immunohistochemical analysis localized gelatinase A close to the plasma membrane of these tissues. Furthermore, recombinant gelatinase A was demonstrated to cleave recombinant amelogenin into several fragments of differing molecular masses. Thus, gelatinase A is expressed by developing tooth tissues along with its activator MT1-MMP and may, therefore, play an important role during tooth development.

Modeled estimates of chlorpyrifos exposure and dose for the Minnesota and Arizona NHEXAS populations

This paper presents a probabilistic, multimedia, multipathway exposure model and assessment for chlorpyrifos developed as part of the National Human Exposure Assessment Survey (NHEXAS). The model was constructed using available information prior to completion of the NHEXAS study. It simulates the distribution of daily aggregate and pathway-specific chlorpyrifos absorbed dose in the general population of the State of Arizona (AZ) and in children aged 3-12 years residing in Minneapolis-St. Paul, Minnesota (MSP). Pathways included were inhalation of indoor and outdoor air, dietary ingestion, non-dietary ingestion of dust and soil, and dermal contact with dust and soil. Probability distributions for model input parameters were derived from the available literature, and input values were chosen to represent chlorpyrifos concentrations and demographics in AZ and MSP to the extent possible. When the NHEXAS AZ and MSP data become available, they can be compared to the distributions derived in this and other prototype modeling assessments to test the adequacy of this pre-NHEXAS model assessment. Although pathway-specific absorbed dose estimates differed between AZ and MSP due to differences in model inputs between simulated adults and children, the aggregate model results and general findings for simulated AZ and MSP populations were similar. The major route of chlorpyrifos intake was food ingestion, followed by indoor air inhalation. Two-stage Monte Carlo simulation was used to derive estimates of both inter-individual variability and uncertainty in the estimated distributions. The variability in the model results reflects the difference in activity patterns, exposure factors, and concentrations contacted by individuals during their daily activities. Based on the coefficient of variation, indoor air inhalation and dust ingestion were most variable relative to the mean, primarily because of variability in concentrations due to use or no-use of pesticides. Uncertainty analyses indicated a factor of 10-30 for uncertainty of model predictions of 10th, 50th, and 90th percentiles. The greatest source of uncertainty in the model stems from the definition of no household pesticide use as no use in the past year. Because chlorpyrifos persists in the residential environment for longer than a year, the modeled estimates are likely to be low. More information on pesticide usage and environmental concentrations measured at different post-application times is needed to refine and evaluate this and other pesticide exposure models.

Effects of mutating different steroidogenic factor-1 protein regions on gene regulation

The involvement of cyclic adenosine monophosphate cAMP-dependent protein kinase A (PKA) in the regulation of the steroidogenic acute regulatory protein (StAR) and the high-density lipoprotein receptor (HDL-R) genes by steroidogenic factor-1 (SF-1) and cAMP were examined. Cotransfection studies carried out in Kin 8 cells, a Y1 cell line (mouse adrenal) with a mutation in the type I PKA regulatory subunit, demonstrated that an intact PKA is required for maximal activation and that SF-1 participates in cAMP regulation of these genes. Site-directed mutational analysis was performed to examine which SF-1 regions could be involved in SF-1 transcriptional activation of the StAR and HDL-R genes. SF-1 regions protein analyzed were amino acids Thr 60, Ser 203, Ser 431, Thr 462, and the activation function-2 domain (amino acids 449-462). Plasmids encoding each of the mutated SF-1 proteins were cotransfected with the StAR and HDL-R promoter constructs into human bladder carcinoma (HTB-9) cells in the presence or absence of dibutyryl cAMP. The results of these studies suggest that although SF-1 is required for optimal promoter response to cAMP, transcriptional activation of genes by SF-1 and cAMP are promoter dependent, perhaps resulting from gene-specific interactions of this transcription factor with other regulatory proteins.

[Improvement of combination chemotherapy tolerance of human umbilical cord blood CD(34)(+) cells transducted with double drug resistance genes by a bicistronic retroviral vector]

OBJECTIVE

To explore whether human umbilical cord blood hematopoietic progenitor cells transduced with human aldehyde dehydrogenase class 3 (ALDH3) and multidrug resistance gene (MDR1) could increase resistance to 4-hydroxycyclophosphamide (4-HC) and P-glycoprotein effluxed drugs.

METHODS

A bicistronic retroviral vector G1Na-ALDH3-IRES-MDR1 cDNA was constructed and transfected the packaging cell lines GP + E86 and PA317 by LipofectAMINE method, using the medium containing VCR and 4-HC for cloning selection and ping-ponging supernatant infection between ecotropic producer clone and amphotropic producer clone, cord blood CD(34)(+) cells were enriched with a high-gradient magnetic cell sorting system (MACS), and then repeatedly transfected with supernatant of retrovirus containing human ALDH3 and MDR1 cDNA under stimulation of hematopoietic growth factors. PCR, RT-PCR, Southern blot, Northern blot, FACS and MTT assay were used to evaluate the transfection and expression of the double genes.

RESULTS

The purity of cord blood CD(34)(+) cells was approximately 91% and the recovery rate was 72%. The highest titer of recombinant amphotropic retrovirus in the supernatant was up to 6.5 x 10(5) CFU/ml. The efficiency of gene transduction was 18%, 20% and 16.7% tested by colony formation, PCR and FACS, respectively. Rhodamine 123 efflux showed 16% transduced cells with P-gp function. No helper virus was found by both nested PCR and rescue assay. The MTT analysis showed a 3.5 to 6.8-fold increase of resistance of transducted cells to cyclophosphamide and P-glycoprotein effluxes drug as compared with the nontransduced cells.

CONCLUSION

The efficiency and co-expression of this dual genes transfer system provided a foundation for ameliorating combination chemotherapy toxicity in clinical trial.

Molecular cloning and sequence analyses of calcium/calmodulin-dependent protein kinase II from fetal and adult human brain. Sequence analyses of human brain calciuum/calmodulin-dependent protein kinase II

The aims of this study were to characterize specific mRNAs and the expression pattern for isoforms of calcium/calmodulin-dependent protein kinase II (CaMKII) in the human brain. We cloned and sequenced the CaMKII alpha and beta subunit cDNAs, and used them to study the CaMKII expression in human brain. Four distinct isoforms of CAMKII were isolated. Two of them were characterized as CaMKII alpha and beta subunits. The other two showed similar nucleotide sequences, but one had a 33-bp insertion relative to the alpha subunit, and the other had a 75-bp deletion relative to the beta subunit. These alterations are located within the variable regions. These two isoforms were characterized as CaMKII alphaB and beta(e). Northern blot analysis showed that a 4.4-kb messenger RNA for the alpha isoform and a 3.9-kb messenger RNA for the beta isoform were expressed in both human fetal and adult brain to different degrees. The results indicate that CaMKII expression is developmentally regulated. The CaMKII isoform expression was confirmed in human fetal and adult brain using RT-PCR with specific primers, which flanked the CaMKII variable regions. The CaMKII alpha, alphaB, beta, beta' and beta(e) isoforms were characterized in both human fetal and adult brain.

Murine enamelin: cDNA and derived protein sequences

Enamelin is the largest enamel protein. Recently we reported the characterization of a cDNA clone encoding porcine enamelin. The secreted protein has 1104 amino acids--over 6 times the length of amelogenin (173 amino acids) and almost 3 times the lengths of sheathlin (395 amino acids) and tuftelin (389 amino acids). Immunohistochemistry has shown that uncleaved porcine enamelin concentrates at the growing tips of the enamel crystallites while its cleavage products localize to rod and interrod enamel. Here we report the isolation and characterization of cDNA encoding murine amelogenin and demonstrate the tooth specificity of porcine enamelin. The murine clone is 4154 nucleotides in length and encodes a protein of 1274 amino acids. In the absence of post-translational modifications murine enamelin has an isotope averaged molecular mass of 137 kDa and an isoelectric point of 9.4. Multiple tissue Northern blot analyses detect porcine enamelin mRNA in developing teeth but not in liver, heart, brain, spleen, skeletal muscle and lung. Mouse and porcine enamelin share 61% amino acid identity and 75% DNA sequence identity. Mouse enamelin has 14 tandemly arranged copies of an 11 amino acid segment that is found only once in porcine enamelin.

Enamelysin mRNA displays a developmentally defined pattern of expression and encodes a protein which degrades amelogenin

Previously, a cDNA encoding a novel matrix metalloproteinase (enamelysin) was isolated from a porcine enamel organ-specific cDNA library. The cloned mRNA is tooth-specific and contains an open reading frame encoding a protein composed of 483 amino acids (Gene, 183:(1-2), p123-128, 1996). Here, we show that: 1) The expression of enamelysin mRNA is not limited to the enamel organ as previously reported. The enamelysin message is also expressed at very low levels in the pulp organ. 2) Northern analysis reveals that the enamelysin mRNA displays a developmentally defined pattern of expression in the enamel organ. The message is expressed at relatively high levels during the presecretory and early transition stages of development. However, during late maturation, the quantity of enamelysin mRNA is greatly reduced. Conversely, the low message levels in the pulp organ remain relatively constant throughout these developmental stages. 3) The enamelysin cDNA was ligated into a prokaryotic expression vector and recombinant enamelysin containing a His tag was purified from E. coli. Zymographic analysis utilizing recombinant murine amelogenin as the substrate, reveals that the purified enamelysin degrades amelogenin. Since enamelysin is developmentally regulated and is capable of degrading amelogenin, it is likely to play a significant role during enamel biomineralization.

Enamel matrix serine proteinase 1: stage-specific expression and molecular modeling

Enamel proteins are cleaved by proteinases soon after their secretion by ameloblasts. Intact proteins concentrate in the outer enamel at or near the growing tips of the enamel crystallites while cleavage products accumulate in the deeper enamel. In the transition and early maturation stages there is a dramatic increase in proteolytic activity. This activity, coupled with the diminished secretory and increased reabsorptive functions of ameloblasts, leads to a precipitous fall in the amount of enamel protein in the matrix. Recently we have cloned and characterized an mRNA encoding a tooth-specific serine proteinase designated enamel matrix serine proteinase 1 (EMSP1) [Simmer et al., JDR (1998) 77: 377]. EMSP1 can be detected in the inner enamel during the secretory stage and its activity increases sharply during the transition stage. Stage-specific Northern blot analysis demonstrates this increase is accompanied by a parallel increase in the amount EMSP1 mRNA. A 3-dimensional computer model of EMSP1, based upon the crystal structure of bovine trypsin, has been generated and analyzed. All six disulfide bridges as well as the active site are conserved. Changes in the peptide binding region and the specificity pocket suggest that interaction of the proteinase with protein substrates is altered, potentially causing a shift in substrate specificity. The calcium binding region of trypsin is thoroughly modified suggesting that the calcium independence of EMSP1 activity is due to an inability to bind calcium. The three potential N-linked glycosylation sites, N104, N139 and N184, are in surface accessible positions away from the active site.

[Single nucleotide polymorphism in beta2-adrenoceptor gene and the distribution in Chinese Han ethnic group]

OBJECTIVE

The study was conducted to investigate single nucleotide polymorphism(SNP) in beta2-adrenoceptor(beta2-AR) gene and the distribution of these identified SNPs in Chinese Han ethnic group.

METHODS

beta2-AR gene was sequenced to detect SNPs by fluorescent labeling automatic sequencing method in 80 unrelated samples from territory of Dabie Mountain in Anhui province.

RESULTS

A total of 8 SNPs were identified in length of 3.8 kb, including 5 SNPs in code region, 3 SNPs in regulatory region. Although the variations, -468C to G, -367T to C, -47C to T,-20T to C, +79C to G, +100G to A, +491C to T, +1098T to C have been identified in other ethnic groups, they have not been found in our study. The allele distribution of SNPs is in good unity with the Hardy-Weinberg equilibrium.

CONCLUSION

The distribution of SNPs in beta2-AR gene is not equable and the SNPs in different ethnic groups differ greatly. The allele distribution of SNPs conforms well to the Hardy-Weinberg equilibrium.

Studies on flavans. 1. Facile synthesis of (+/-)-7-hydroxy-3',4'-methylenedioxyflavan and (+/-)-4'-hydroxy-7-methoxyflavan by a BF3.Et2O-mediated pyran cyclization

A facile approach for the synthesis of flavans was developed by employing a BF3.Et2O-catalyzed pyran cyclization in an aprotic polar solvent as a key step, by which concise total syntheses of (+/-)-7-hydroxy-3',4'-methylenedioxyflavan (1) and (+/-)-4'-hydroxy-7-methoxyflavan (2), two naturally occurring flavans, were achieved.

[Association of single nucleotide polymorphisms in code region of beta2-adrenoceptor gene with hypertension in Chinese population]

OBJECTIVE

To detect single nucleotide polymorphisms(SNPs) existing in code region of beta(2)-adrenoceptor(2-AR) gene and to investigate association of the identified SNPs with essential hypertension in Chinese Han population.

METHODS

Beta(2)-AR gene was sequenced with fluorescent labelling automatic sequencing method in unrelated Chinese Han population from Dabie Mountain in Anhui Province. Genotype of the SNPs were typed with PCR-RFLP method.

RESULTS

Two SNPs were identified in length of 774bp, at position + 1053 with G-->C substitution and + 1239 with A-->G substitution respectively. The frequency of genotype of the two SNPs complied well with the Hardy-Weinberg equilibrium in normal group. Distribution of genotype AA, GA, GG of the SNPs at locus + 1239 in hypertension group was significantly different from that in normal group (chi(2) = 6.70, df = 2, P < 0.05). No significant difference was observed in distribution of genotypes of the SNPs at locus + 1053 between the two groups.

CONCLUSION

These results indicate that the SNPs at locus + 1239 of beta(2)-AR gene is associated with EH. The SNPs at position + 1053 was not linked to hypertension.

A bicistronic retroviral vector to introduce drug resistance genes into human umbilical cord blood CD34+ cells to improve combination chemotherapy tolerance

OBJECTIVE

To study whether human umbilical cord blood CD34+ cells transduced with human aldehyde dehydrogenase class-1 (ALDH-1) and multidrug resistance gene (MDR1) have increases resistance to 4-Hydroperoxycyclo-phosphamide (4-HC) and P-glycoprotein effluxed drugs.

METHODS

A bicistronic retroviral vector G1Na-ALDH1-IRES-MDR1 was constructed and used to transfect the packaging cell lines GP + E86 and PA317 by LipofectAMINE method, using the medium containing VCR and 4-HC agents for cloning selection and ping-ponging supernatant infection between the ecotropic producer clone and the amphotropic producer clone, we obtained high titer amphotropic PA317 producing cells with high titers up to 5.6 x 10(5) CFU/ml. Cord blood CD34+ cells were transfected repeatedly with supernatant of retrovirus containing human ALDH-1 and MDR1cDNA under the stimulation of hemopoietic growth factors.

RESULTS

Bicistronic retroviral vector construction was verified by restriction endonuclease analysis. Polymerase chain reaction (PCR), reverse transcription (RT)-PCR, Southern blot, Northern blot, fluorescenceactivated cell sorting (FACS) method and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) analyses showed that dual drug resistance genes have been integrated into the genomic DNA of cord blood CD34+ cells and expressed efficiently. The transgenes recipient cells confered 4-fold stronger resistance to 4-HC and 5.5 to 7.2-fold P-glycoprotein effluxed drug than untransduced cells.

CONCLUSION

The bicistronic retroviral vector-mediated transfer of two different types of drug resistance genes into human cord blood CD34+ cells and co-expression provided an experimental foundation for improving combination chemotherapy tolerance in tumor clinical trial.

Brain tissue classification of magnetic resonance images using partial volume modeling

This paper presents a fully automatic three-dimensional classification of brain tissues for Magnetic Resonance (MR) images. An MR image volume may be composed of a mixture of several tissue types due to partial volume effects. Therefore, we consider that in a brain dataset there are not only the three main types of brain tissue: gray matter, white matter, and cerebro spinal fluid, called pure classes, but also mixtures, called mixclasses. A statistical model of the mixtures is proposed and studied by means of simulations. It is shown that it can be approximated by a Gaussian function under some conditions. The D'Agostino-Pearson normality test is used to assess the risk alpha of the approximation. In order to classify a brain into three types of brain tissue and deal with the problem of partial volume effects, the proposed algorithm uses two steps: 1) segmentation of the brain into pure and mixclasses using the mixture model; 2) reclassification of the mixclasses into the pure classes using knowledge about the obtained pure classes. Both steps use Markov random field (MRF) models. The multifractal dimension, describing the topology of the brain, is added to the MRFs to improve discrimination of the mixclasses. The algorithm is evaluated using both simulated images and real MR images with different T1-weighted acquisition sequences.

[In vitro study on transduction of human O(6)-methylguanine-DNA-methyltransferase cDNA into human umbilical cord blood CD34(+) cells]

OBJECTIVE

To explore human umbilical cord blood hematopoietic progenitor cells transduced with human O(6)-methylguanine-DNA-methyltransferase (MGMT) gene increase resistance to 1,3-Bis(2-Chloroethyl)-1-Nitrosourea(BCNU).

METHODS

The present authors obtained a full length cDNA fragment encoding the human MGMT from a patient with cholelithiasis liver tissue by RT-PCR method and confirmed by DNA sequencing. The fragment was cloned into pGEM-T vector and further subcloned into G1Na retrovirus vector. Then the G1Na-MGMT was transfected into the packaging cell lines GP+E86 and PA317 by LipofectAMINE method; using the medium containing BCNU for cloning selection and ping-ponging supernatant infection between ecotropic producer clone and amphotropic producer clone, the authors obtained high titer amphotropic PA317 producer clone with the highest titer up to 1.6x10(6) CFU/ml. Cord blood CD34(+) cell were transfected repeatedly with supernatant of retrovirus containing human MGMT cDNA under stimulation of hemopoietic growth factors.

RESULTS

PCR, RT-PCR, Southern blot, Northern blot, Western blot and MTT analyses showed that MGMT gene had been integrated into the genomic DNA of cord blood CD34(+) cells and expressed efficiently in the transfected cells. The transgene recipient cells conferred 4 folds stronger resistance to BCNU than that of the non-transduced.

CONCLUSION

The retrovirus vector-mediated transfer of MGMT drug resistance gene into human cord blood CD34(+) cells and expression could confer the resistance of transgene cells to BCNU toxicity.

[Study on the aggregation state of sulfonated phthalimidomethyl zinc phthalocyanine in CEL solution]

Sulfonated Phthalimidomethyl Zinc Phthalocyanine is a new photodynamic therapy reagent, it can be selectively attacked to cell, but how it attacks the target cell is still unknowable. The aggregation state of photosensitizer is significant to its mechanism proved in CEL solution. The aggregation of ZnPcS2P2 in CEL has been studied with absorption spectroscopy and fluorescence spectroscopy. The aggregation state is dimer through theory analysis, monomer molar absorption coefficient as well as equilibrium constant were estimated.

Charge-density-wave-induced modifications to the quasiparticle self-energy in 2H- TaSe2

The self-energy of the photohole in 2H-TaSe2 is measured by angle-resolved photoemission spectroscopy as a function of binding energy and temperature. In the charge-density wave (CDW) state, a structure in the self-energy is detected at approximately 65 meV that cannot be explained by electron-phonon scattering. A reduction in the scattering rates below this energy indicates the collapse of a major scattering channel with the formation of the CDW state accompanying the appearance of a bosonic "mode" in the excitation spectrum of the system.

Amperometric ultramicrosensors for peroxynitrite detection and its application toward single myocardial cells

The research studied the concentration variation of peroxynitrite anion (O=N-O-O-) released from cultured neonatal myocardial cells induced by ischemia/reperfusion and studied the protective effect of melatonin on the injury. For this purpose, amperometry peroxynitrite ultramicrosensors (UMS) were fabricated and constructed by electropolymerizing inorganic macromolecular film of tetraaminophthalocyanine manganese(II) and coating chemically with poly(4-vinylpyridine). Under optimum conditions, the UMS showed high selectivity and sensitivity to peroxynitrite determination with a calculated detection limit of 1.8 x 10(-8) mol/L (S/N of 3). The detection of peroxynitrite was based on electrocatalytic reduction of peroxynitrite. The mechanism of catalysis was also discussed. The UMS should be promising for in vivo measurement of peroxynitrite without interference or fouling. Peroxynitrite released from myocardial cells both in the ischemic period and in the reperfusion period was measured directly. This approach may lead to important information for myocardial cells on the mechanism of injury and prospective treatments of medicine such as melatonin.

Infarct tolerance accompanied enhanced BDNF-like immunoreactivity in neuronal nuclei

A prolonged period (48 h) of cortical spreading depression (CSD) induced resistance against severe focal cerebral ischemia (infarct tolerance), however, the mechanism behind this is unknown. The infarct tolerance was a transient phenomenon; the resistance increased linearly for the initial 12 days, peaking from 12 to 15 days after a preconditioning of CSD, and was decreased thereafter. This study examined the time course of brain-derived neurotrophic factor (BDNF), heat shock protein (hsp)27 and 70, and glial fibrillary acidic protein (GFAP) expressions after CSD in the brain. Immunohistochemical expression of BDNF, hsp27, hsp70, or GFAP following a prolonged period of CSD induced by KCl-infusion, or following NaCl-infusion was analyzed by regional densitometry for 24 days in the rat neocortex. In addition, BDNF protein was measured quantitatively by two-site ELISA assay in the neocortex (n=6 at each time point). The GFAP expression was elevated in astrocytes (compared to the normal level of immunodensity) during the period peaking on day 3-6 following the CSD. The hsp27 immunoreactivity was also elevated in astrocytes from day 1 to 12 peaking on day 1 and 6, but there was no expression of hsp70 during the period following CSD. The immunoreactivity for BDNF was elevated in neurons from day 0 to 18 peaking on day 1 and 6. The protein levels of BDNF in the neocortex were significantly elevated from day 0 to 12 peaking on days 0 and 6 (compared to the normal level) (P<0.05). Using a laser-scanning confocal imaging system, the BDNF-like immunoreactivity in neuronal nuclei was found to increase linearly peaking on day 12, which correlated well with the development of infarct tolerance. The intranuclear increase in BDNF-like protein might contribute to the induction of infarct tolerance in the brain.

Photoinduced reactions of 1-acetylisatin with phenylacetylenes

[reaction: see text]Photoinduced reactions of 1-acetylisatin 1 with diphenylacetylenes 2a-2c afforded the corresponding 3-methylene-2-indolones 4a-4e and 5a-5e in 80-90% yields via a spirooxetene intermediate. Similar irradiation of 1 with phenylacetylene, on the other hand, resulted in efficient formation of two diastereoisomeric dispiro[3H-indole-3,2'-furan-3',3"-(3H)-indole]-2,5',2"(2H,5'H,2"H )triones 6 and 7 via a reaction sequence with initial formation of the spirooxetene intermediate. The regioselectivity in the photocycloaddition of 1 with phenylacetylene and the reaction mechanism for the formation of 6 and 7 are discussed.

[Expression of substance P receptor mRNA in nasal mucosa of rat in allergic rhinitis model]

OBJECTIVE

To study the expression of substance P receptor messenger RNA (SP-R mRNA) in nasal mucosa in allergic rhinitis (AR) rat model.

METHODS

Twenty Wistar rats free of disease were randomly divided into two groups. AR model rats were established through repeated intraperitoneal shot of ovalbumin (OV) and consequently confirmed by local challenge with OV. SP-R mRNA in nasal mucosa, obtained from two groups, were used to do reverse transcriptive polymerase chain reaction (RT-PCR) and Southern blot. beta-actin was used as a standard control through out the whole process.

RESULTS

The results showed definitely that there were positive expression of SP-R mRNA in normal nasal mucosa. This expressions increased significantly (P < 0.05) during nasal allergy.

CONCLUSION

Increased expression SP-R mRNA in nasal mucosa in AR model might play roles in the development of AR.

Measurement of nitric oxide released in the rat heart with an amperometric microsensor

Nitric oxide (NO) plays an important role in various physiological processes, acting either as an intra- and intercellular messenger or as a toxic agent. The detection and quantification of NO have been accomplished by a variety of methodologies. In the present study, real-time production of NO in the rat heart was continuously measured by using a novel copper-platinum microparticle-modified NO electrochemical microsensor. The linearity range of the microsensor is between 8.0 x 10(-8) and 4.8 x 10(-6) mol L-1 and the detection limit is 3.0 x 10(-8) mol L-1. NO release from the rat heart stimulated by the agonists L-arginine and acetylcholine was observed, and the responses were decreased by the NO synthase inhibitor L-N omega-nitroarginine. In addition, the effect of sodium nitroprusside (SNP), a NO donor, was also studied. SNP increases the concentration of NO in the rat heart. The experiments showed that electrochemical detection is suitable for detecting and quantifying NO in biological systems.

Relative abundance of placental pro-atrial natriuretic factor mRNA in normal pregnancy and pre-eclampsia

Atrial natriuretic factor (ANF), produced by cytotrophoblast cells of the human placenta, may be involved in the regulation of uteroplacental blood flow. Pre-eclampsia is associated with maternal hypertension and reduced uteroplacental perfusion. The relationship between pre-eclampsia and placental production of ANF is not known. This study measured pro-ANF mRNA levels by Northern blot analysis in placentae delivered by caesarean section at preterm and term gestations from women with normotensive and pre-eclamptic pregnancies and found no significant difference between pre-eclampsia and normal pregnancy at either gestation. This result suggests that placental production of ANF is not altered at the pretranslational level during pre-eclampsia.

qBrain-2, a POU domain gene expressed in quail embryos

We isolated a quail class III POU domain gene, qBrain-2, which was cloned from a cDNA library of E5 embryos. Northern blot and in situ hybridization analyses showed that qBrain-2 was expressed in developing central nervous system and adult brain. Moreover, qBrain-2 transcripts showed a dynamic distribution in embryonic central nervous system. Its transcripts were dominantly detected in the ventricular zone of the developing brain and spinal cord, but rarely in the differentiated region of mantle zone as well as the non-neuronal roof plate and floor plate. This suggests that qBrain-2 is involved in proliferation and differentiation of the neuroepithelial cells of quail central nervous system.

Phosphorylation of a new brain-specific septin, G-septin, by cGMP-dependent protein kinase

The septins are a family of GTPase enzymes, some of which are required for the cytokinesis stage of cell division and others of which are associated with exocytosis. We purified and cloned the cDNA for a 40-kDa protein from rat brain that is a substrate for type I cGMP-dependent protein kinase (PKG). The amino acid sequences of two tryptic peptides of P40 showed high homology to the septins. Molecular cloning revealed the 358-amino acid P40 to be a new member of the septin family. P40 was named G-septin, as it is phosphorylated in vitro by PKG, but relatively poorly by the related cAMP-dependent protein kinase and not by protein kinase C. Two splice variants of G-septin (alpha and beta) were found with distinct N and C termini, but a common GTPase domain. G-septin lacks the C-terminal coiled-coil domain characteristic of all other mammalian septins and uniquely has two predicted phosphorylation site motifs for type I PKG. Photoaffinity labeling with [alpha-(32)P]GTP confirmed that G-septin is a GTP-binding protein. Northern blotting showed that G-septin mRNA (5.0 kilobases) is highly expressed in brain and undetectable in 12 other tissues, indicating that the G-septins are primarily neuronal proteins. Very low levels of 6.0-, 3.4-, and 2.6-kilobase transcripts were found in testis. Our results reveal a new class of brain-specific septins that may be regulated by PKG in neurons.

[Information behavior of microsatellite loci in genome scanning]

OBJECTIVE

To determine the heterozygosity and polymorphism information content of 139 microsatellite loci in Han population.

METHODS

Multiplex approach was used to analyze the 139 loci. The amplified fragments were subjected to electrophoresis in PAGE gel and analyzed with Genescan( TM) and Genotyper(TM).

RESULTS

The heterozygosities are between 0.35 to 0.89, with the heterozygosities of 88% loci >0.60. PICs are in the range of 0.32 and 0.88, with PICs of 95% loci >0.50.

CONCLUSION

The polymorphism information content of microsatellite loci is very high and their distribution varies in different races and populations.

The Harvard Southern California Chronic Ozone Exposure Study: assessing ozone exposure of grade-school-age children in two Southern California communities

The Harvard Southern California Chronic Ozone Exposure Study measured personal exposure to, and indoor and outdoor ozone concentrations of, approximately 200 elementary school children 6-12 years of age for 12 months (June 1995-May 1996). We selected two Southern California communities, Upland and several towns located in the San Bernardino mountains, because certain characteristics of those communities were believed to affect personal exposures. On 6 consecutive days during each study month, participant homes were monitored for indoor and outdoor ozone concentrations, and participating children wore a small passive ozone sampler to measure personal exposure. During each sampling period, the children recorded time-location-activity information in a diary. Ambient ozone concentration data were obtained from air quality monitoring stations in the study areas. We present ozone concentration data for the ozone season (June-September 1995 and May 1996) and the nonozone season (October 1995-April 1996). During the ozone season, outdoor and indoor concentrations and personal exposure averaged 48.2, 11.8, and 18.8 ppb in Upland and 60.1, 21.4, and 25.4 ppb in the mountain towns, respectively. During the nonozone season, outdoor and indoor concentrations and personal exposure averaged 21.1, 3.2, and 6.2 ppb in Upland, and 35.7, 2.8, and 5.7 ppb in the mountain towns, respectively. Personal exposure differed by community and sex, but not by age group.

[Impact of short-term increase in air pollution on mortality of the population]

The authors analyzed whether there is an association of mortality with ambient air pollution analyzed in Yekaterinburg and Nizhni Tagil in 1994 to 1997. There was a positive correlation between general mortality and CO or SO2 concentrations, between cardiovascular mortality and dust, NH3 or phenol, between mortality and CO or NH3. An increase of deaths as percents per 10 micrograms/m3 dust was calculated.

A novel electrochemical microsensor for the determination of NO and its application to the study of the NO donor S-nitrosoglutathione

A novel electrochemical microsensor for the determination of NO based on an electropolymerized film of tetraaminophthalocyaninecopper [Cu(TAPc)] was prepared. Its response to NO and its application to the study of an NO donor (S-nitrosoglutathione; GSNO) are also described. The microsensor exhibited an electrocatalytic effect on NO oxidation and showed a low detection limit, high sensitivity and selectivity for NO determination. The oxidation current (measured by differential pulse amperometry) was linear for NO concentrations ranging from 6.2 x 10(-9) to 3.0 x 10(-5) mol L-1 with a calculated detection limit of 4.0 x 10(-9) mol L-1 (S/N = 3) and a linear coefficient of 0.9984. Some endogenous electroactive substances in biological tissues, such as dopamine, 5-hydroxytryptamine and nitrite, at concentrations higher than those in biological systems did not interfere with NO determination. The sensor shows promise for the possible in vivo determination of NO. Using the microsensor, the NO release from the NO donor (GSNO) was successfully monitored. This work sets a foundation for the study of the pharmacology and the biological effects in vivo of S-nitrosothiols.

Effects of intrinsic nitric oxide on the expression of interleukin-4 and IFN-gamma mRNA in the bronchial and lung tissues of sensitized rats

To investigate the effects of intrinsic nitric oxide (NO) on the expression of interleukin-4 (IL-4) mRNA and interferon-gamma (IFN-gamma) mRNA in the airway inflammation of asthma, the rat models of asthmatic inflammation were established by sensitizing and then challenging the animals with ovalbumin. The 24 animals were randomly divided into control group, sensitized group, sensitized and L-Arg-treated group as well as L-NAME-treated group equally. By using in situ hybridization combined with compute physiological quantitative imaging analysis techniques, the influence of intrinsic NO on the expression of IL-4 mRNA and IFN-gamma mRNA in the airway inflammatory cells was observed. In situ hybridization study demonstrated that IL-4 mRNA expression was obviously increased as compared with that in the control group, mainly distributed in the inflammatory cells in the submucous of airways in the sensitized group. The increase of intensity of IL-4 mRNA expression was positively correlated with the numbers of eosinophil (Eos) and lymphocyte (both with P < 0.05) in the sensitized group. There was no statistically difference in IFN-gamma expression between the control group and the sensitized group. Imaging analysis showed that L-NAME could inhibit the expression of IL-4 mRNA (P < 0.05) and increase the expression of IFN-gamma mRNA (P < 0.05), while L-Arg could increase the expression of IL-4 mRNA in inflammatory cells (P < 0.05). It was indicated that a suitable levels of intrinsic NO can influence the expression of IL-4 mRNA of Th2 lymphocytes and the expression of IFN-gamma mRNA of Th1 lymphocytes and in turn, promote the development of asthmatic airway inflammation.