Neutron radiation area monitoring system for proton therapy facilities

A neutron radiation area monitoring system has been developed for proton accelerator facilities dedicated to cancer therapy. The system comprises commercial measurement equipment, computer hardware and a suite of software applications that were developed specifically for use in a medical accelerator environment. The system is designed to record and display the neutron dose-equivalent readings from 16 to 24 locations (depending on the size of the proton therapy centre) throughout the facility. Additional software applications provide for convenient data analysis, plotting, radiation protection reporting, and system maintenance and administration tasks. The system performs with a mean time between failures of >6 months. Required data storage capabilities and application execution times are met with inexpensive off-the-shelf computer hardware.

The Xenopus noggin promoter drives roof-plate specific transcription

During vertebrate neural development, inductive signals derived from the roof plate specify dorsal neural cell types of spinal cord as well as adjacent dermomytotome. Noggin has been demonstrated to play a pivotal role in this signaling network but how its expression is regulated remains unclear. To investigate this issue, we identified a 2066 bp Xenopus noggin 5' flanking sequence which recapitulates the roof-plate expression of endogenous gene in transgenic frog tadpoles and we further mapped the roof-plate enhancer to a sequence as short as 79 bp. Our results, therefore, not only shed light on but also provide a powerful tool to the study of neural and somite patterning.

Structural features and hypoglycaemic activity of an exopolysaccharide produced by Sorangium cellulosum

AIMS

To investigate the structural features and hypoglycaemic activity of an exopolysaccharide (EPS) produced by Sorangium cellulosum NUST06.

METHODS AND RESULTS

The chemical structure of the EPS from S. cellulosum NUST06 was determined by gas-liquid chromatography, gas chromatography (GC), GC-mass spectrometry and nuclear magnetic resonance. The EPS was composed of a beta-D-(1-->4)-glucose backbone with alpha-D-(1-->6)-mannose side chains. The molecular weight of the EPS was approx. 2x10(5) Da. Healthy and alloxan-induced diabetic mice were used in the study. Blood glucose levels of the experimental animals during the trial period were analysed by a glucose test kit based on the glucose oxidase method. When 100 and 200 mg kg(-1) day(-1) of purified EPS was orally administered for 7 days, the serum glucose in alloxan-induced diabetic mice was reduced by 35.9 and 41.4% (P<0.01), and the serum glucose in healthy mice was reduced by 27.3 and 30.1% (P<0.05), respectively.

CONCLUSIONS

The EPS produced by S. cellulosum NUST06 decreased blood glucose levels distinctly in both healthy and alloxan-induced diabetic mice.

SIGNIFICANCE AND IMPACT OF THE STUDY

To elucidated the chemical structure of the EPS from S. cellulosum NUST06 and exploited the anti-diabetic potential of the EPS.

Activin/Nodal signals mediate the ventral expression of myf-5 in Xenopus gastrula embryos

Expression of myf-5, a key component of myogenic regulatory genes, expands into the ventral marginal zone during Xenopus gastrulation after the dorsal activation takes place. Little is known about how this dynamic expression pattern occurs. Here, we provide evidences to suggest that Activin/Nodal signals participate in the regulation of ventral expression of Xmyf-5 in gastrula embryos. Two Smad binding elements (SBEs) within the Xenopus myf-5 promoter can specifically interact with Smad4 protein. Furthermore, we demonstrate that the two SBEs are both indispensable for conferring responsiveness to Activin/Nodal signals and to ventral expression of myf-5 in Xenopus gastrula embryos.

Stage-specific expression of breast cancer-specific gene gamma-synuclein

Gamma-synuclein (SNCG), also referred as breast cancer-specific gene 1, is the third member of a neuronal protein family synuclein. SNCG is highly expressed in human-infiltrating breast carcinomas but not expressed in normal or benign breast tissues. To evaluate the clinical relevance of SNCG expression in breast cancer progression and its correlation with clinical parameters, we analyzed SNCG expression in 79 clinical breast specimens from primary breast cancer, hyperplasia, and fibroadenoma patients by reverse transcription-PCR. The status of estrogen receptor, progesterone receptor, proliferating cell nuclear antigen, and C-erBb2 was also analyzed by immunohistochemistry. Overall SNCG mRNA expression was detectable in 38.8% of breast cancers. However, 79% of stage III/IV breast cancers were positive for SNCG expression, whereas only 15% of stage I/II breast cancers were positive for SNCG expression. In contrast, the expression of SNCG was undetectable in all benign breast lesions. The expression of SNCG was strongly correlated to the stage of breast cancer (P=0.000). This study suggests that the expression of SNCG is stage specific for breast cancer. SNCG is expected to be a useful marker for breast cancer progression and a potential target for breast cancer treatment.

Lef/Tcf-dependent Wnt/beta-catenin signaling during Xenopus axis specification

Though the Wnt/beta-catenin signaling pathway is known to play key roles during Xenopus axis specification, whether it signals exclusively through Lef/Tcf transcription factors in this process remains unclear. To investigate this issue, we generated transgenic frog embryos expressing green fluorescent protein (GFP) driven by a Lef/Tcf-dependent and Wnt/beta-catenin-responsive promoter. This promoter is highly sensitive and even detects maternal beta-catenin activity prior to the large-scale transcription of zygotic genes. Unexpectedly, GFP expression was observed only in some, but not all, known Wnt/beta-catenin-positive territories in Xenopus early development. Furthermore, ubiquitous expression of dominant Lef-1 protein variants from transgenes revealed that zygotic Lef/Tcf activity is required for the ventroposterior development of Xenopus embryos. In summary, our results suggest that endogenous Wnt/beta-catenin activity does not result in obligatory Lef/Tcf-dependent gene activation, and that the ventroposteriorizing activity of zygotic Wnt-8 signaling is mediated by Lef/Tcf proteins.

Clinical features of endophthalmitis after vitreoretinal surgery

PURPOSE

To investigate the rate, clinical features, treatment outcomes and prognosis of postvitrectomy endophthalmitis.

METHODS

Patients undergoing pars plana vitrectomy for vitreous opacity or complicated retinal detachment during 1988 to 2000 were collected. Vitrectomies for recent penetrating trauma or endophthalmitis were excluded. Patients suffered from clinical or culture-proven postvitrectomy endophthalmitis were selected.

RESULTS

Postvitrectomy endophthalmitis happened to 3 to 7,000 patients, resulting in an overall frequency of 0.04%. Enhanced systemic and local antibiotics were used as soon as diagnosis was made. Endophthamitis were controlled within 6 days, 8 days and 10 days, respectively. Final visual acuities were light perception in 2 patients and 0.02 in 1 patient.

CONCLUSION

Postvitrectomy endophthalmitis was rare, but it deteriorate the visual acuity. Both ophthalmologist and patients should pay high attention to it.

T-box binding site mediates the dorsal activation of myf-5 in Xenopus gastrula embryos

Myf-5, a member of the muscle regulatory factor family of transcription factors, plays an important role in the determination, development, and differentiation of the skeletal muscle. Factors that regulate the expression of myf-5 itself are not well understood. We show here that a T-box binding site in the Xenopus myf-5 promoter mediated the activation of myf-5 expression through specific interaction with nuclear proteins of gastrula embryos. The T-box binding site could be bound by and respond to T-box proteins. T-box genes could induce Xmyf-5. The results suggest that T-box proteins are involved in the specification of myogenic mesoderm and muscle development.

[Studies on diterpenoids from the roots of Euphorbia ebracteolata]

Euphorbia ebractolata has been used as insecticide and tuberculocide. Four crystalline compounds were isolated from the root of this plant. They were characterized by their physico-chemical properties and spectral data as: 3-acety alpha-amyrin (I), Jolkinolide B (II), ebracteolatanolide A (III) and ebracteolatanolide B (IV). I and II were isolated for the first time from E. ebracteolata Hayata. III and IV are new compounds.

Organochlorine pesticides and polychlorinated biphenyl residues in foodstuffs and human tissues from china: status of contamination, historical trend, and human dietary exposure

Concentrations of persistent organochlorine pesticides such as DDTs, hexachlorocyclohexanes (HCHs), chlordane compounds (CHLs), hexachlorobenzene (HCB), and polychlorinated biphenyls (PCBs), were determined in a wide variety of foodstuffs and human tissues collected from Shanghai and its vicinity in China in 2000-2001. Among the organochlorines analyzed, DDT and its metabolites were prominent compounds in most of the foodstuffs. In particular, mussels contained noticeable residues of DDTs (34,000 ng/g lipid weight), which are one to three orders greater than those reported levels in bivalves from other Asian countries. Concentrations of HCHs, CHLs, HCB, and PCBs in foodstuffs were generally low, suggesting small amounts of inputs into the environment. Temporal trends examined by comparing the results of previous studies of organochlorine levels in Chinese foodstuffs in 1970s and 1992 revealed a greater amounts of declines of DDTs and HCHs residues and the average daily intakes during the past 30 years. In contrast, very high concentrations of DDTs and HCHs were detected in human tissues from Shanghai, with the maximum values as high as 19,000 ng/g lipid weight (mean: 7,600 ng/g) and 17,000 ng/g (mean: 7,400 ng/g), respectively. Considering that foodstuffs are a main source of human exposure to contaminants, the greater concentrations of DDTs and HCHs in Chinese people might be due to past extensive usage of these compounds as agricultural pesticides. Continuous monitoring and epidemiological studies of organochlorine pesticides in humans are warranted in China. To our knowledge, this is the first report to present the residue levels of persistent organochlorine pesticides and PCBs in human tissues of China.

Repression through a distal TCF-3 binding site restricts Xenopus myf-5 expression in gastrula mesoderm

The development of skeletal muscle in the vertebrate embryo is controlled by a transcriptional cascade that includes the four myogenic regulatory factors Myf-5, MyoD, Myogenin, and MRF4. The dynamic expression pattern of myf-5 during myogenesis is thought to be consistent with its role during early determination of the myogenic lineage. To study the factors and mechanisms, which regulate myf-5 transcription in Xenopus, we isolated a genomic DNA clone containing 4858 bp of Xmyf-5 5' flanking region. Using a transgenic reporter assay, we show here that this genomic contig is sufficient to recapitulate the dynamic stage- and tissue-specific expression pattern of Xmyf-5 from the gastrula to tail bud stages. For the primary induction of myf-5 transcription, we identify three main regulatory elements, which are responsible for (i) activation in dorsal mesoderm, (ii) activation in ventral mesoderm, and (iii) repression in midline mesoderm, respectively. Their combined activities define the two-winged expression domain of myf-5 in the preinvoluted mesoderm. Repression in midline mesoderm is mediated by a single TCF binding site located in the 5' end of the -4.8 kbp sequence, which binds XTcf-3 protein in vitro. Endogenous Wnt signaling in the lateral mesoderm is required to overcome the long-range repression through this distal TCF site, and to stimulate myf-5 transcription independently from it. The element for ventral mesoderm activation responds to Activin. Together, these results describe a regulatory mosaic of repression and activation, which defines the myf-5 expression profile in the frog gastrula.

[An experimental study on effect of perfluorohexyloctane on corneal endothelial cells]

OBJECTIVE

To investigate the effect of perfluorohexyloctane on corneal endothelial cells in rabbit eyes.

METHODS

Fifteen New Zealand albino rabbits were divided into two groups: experiment group (F(6)H(8)) and control group (BSS). All rabbits underwent anterior chamber injection of 0.15 ml F(6)H(8) or BSS. Slit-lamp biomicroscopy and corneal endothelium photography were performed pre- and post-injection. Histopathological examination and transmission electron microscopy (TEM) were performed after the rabbits were sacrificed.

RESULTS

All the corneas were clear. Since 4 weeks postoperatively, the endothelial cells were markedly irregular in size and shape, and the number of endothelial cells was markedly decreased. Multilayered retrocorneal membranes grew gradually from 4 weeks after surgery. Vacuolar degeneration was seen in some endothelial cells. Nuclear degeneration and edema of endoplasmic reticulum were seen in TEM.

CONCLUSION

Corneal endothelial cells degenerated after contacting with F(6)H(8) for 4 weeks. As a silicone solvent, F(6)H(8) should be removed out completely after injection. It is not recommended to apply this agent as a new intraocular temponade.

Experimental study of effect of perfluorohexyloctane to retina

OBJECTIVE

To investigate the effect of perfluorohexyloctane to the retina of rabbit eyes.

METHODS

Perfluorohexyloctane (experimental group) or BSS(control group) into vitreous cavities of fifteen vitrectomized New Zealand white rabbits. A slit-lamp biomicroscope and an indirect ophthalmoscope were used to examine all the eyes pre- and postoperation. Histopathological examination was performed after the rabbits were sacrificed.

RESULTS

Perfluorohexyloctane was injected into the vitreous cavity forming a single large layerclear globe. No retinal detachment and cataract were found. The edema of outer plexiform was significant, and then get a darker cytoplasm and nucleoplasm.

CONCLUSIONS

Perfluorohexyloctane in vitreous cavity had significant side effects on retina. As a silicone solvent, it should be removed out completely after injection. We don't recommend to use it as a new intraocular tamponade.

Activation of the NPTA element of the CYP2A3 gene by NFI-A2, a nasal mucosa-selective nuclear factor 1 isoform

The aim of this study was to determine whether the NPTA element of the olfactory mucosa-predominant CYP2A3 gene can be activated by NFI-A2, a recently identified member of the nuclear factor 1 family of transcription factors. Isoform-specific RNA-PCR confirmed that NFI-A2 is mainly expressed in rat olfactory mucosa. A full-length NFI-A2 cDNA was isolated from a cDNA library of rat olfactory mucosa and was used for preparation of a construct encoding a fusion protein of NFI-A2 with the yeast GAL4 activation domain. Expression of the fusion protein in yeast was detected with an antibody to NFI-A. The fusion protein activated the expression of a LacZ reporter gene in yeast one-hybrid assays with a reporter construct containing the NPTA element, but not with other constructs lacking the NPTA element. These findings suggest that NFI-A2 may be involved in the tissue-selective transcriptional activation of the CYP2A3 gene in the olfactory mucosa.

Expression of inhibitory "killer cell lectin-like receptor G1" identifies unique subpopulations of effector and memory CD8 T cells

T cell and natural killer (NK) cell functions are regulated by triggering of activating and inhibitory cell surface receptors. Here, we have studied the expression profile and predicted inhibitory function of mouse "killer cell lectin-like receptor G1" (KLRG1) on CD8 T cells. KLRG1 was present on 1 - 3 % of adult splenic CD8 cells that expressed CD8alpha beta heterodimers as well as a polyclonal TCR Vbeta repertoire indicative of conventional CD8 cells. The majority of KLRG1(+) CD8 cells belonged to the memory pool as determined by extensive phenotypic marker analysis. Spontaneous IFN-gamma production by approximately 20 % of KLRG1(+) CD8 cells identified them as pro-inflammatory effector cells. In contrast to NK cells, Ly49 and KLRG1 expression on CD8cells was found to be mutually exclusive. Therefore, distinct programs regulate KLRG1 expression in CD8 and NK cells. Finally, we provide evidence that KLRG1 triggering interferes with TCRalpha beta-mediated Ca(++) mobilization and cytotoxicity, raising the possibility that KLRG1 functionally participates in down-regulation of CD8 T cell responses.

An interferon regulatory factor-like binding element restricts Xmyf-5 expression in the posterior somites during Xenopus myogenesis

The expression of myf-5, a key component of myogenic regulatory genes, declines progressively in mature somitic cells during vertebrate myogenesis. Little is known about how this down-regulation takes place. Here we provide evidence that an interferon regulatory factor binding element (IRF element) within the Xenopus myf-5 promoter is responsible for the elimination of myf-5 transcription in mature somitic mesoderm of Xenopus embryos. We show that this IRF element mediates the down-regulation of Xmyf-5 transcription in gastrula embryos, and can specifically interact with nuclear proteins of early neurula. Moreover, deletion of this IRF element results in the anterior expansion of reporter gene transcripts within somitic mesoderm in transgenic embryos. Our results, therefore, provide insight into how the negative control of Xmyf-5 expression takes place.

Depentylation of the rat esophageal carcinogen, methyl-n-pentylnitrosamine, by microsomes from various human and rat tissues and by cytochrome P450 2A3

Methyl-n-pentylnitrosamine (MPN) is carcinogenic for the rat esophagus. To determine organ specificity for MPN activation by human tissues, microsomes isolated from human organs (snap-frozen <6 h after death or removed surgically) were incubated with [pentyl-(3)H]MPN, and [(3)H]pentaldehyde formation was measured by high-pressure liquid chromatography of its 2,4-dinitrophenylhydrazone using radioflow assay. With 100 microM MPN, mean depentylation rates were 6.6 (liver), 2.9 to 3.8 (kidney, stomach, small intestine, and colon), and 0.4 to 1.6 (esophagus, lung, and skin) pmol of pentaldehyde/mg of protein/min. Of 14 human esophagi, four showed relatively high depentylation rates of 3.3 to 4.1 pmol/mg/min. Apparent K(m) was 80 to 160 microM (V(max), 3-15 pmol/mg/min) for three esophagi, 90 to 130 (2 livers), and 1330 (1 kidney) microM. Rat tissues showed mean depentylation rates for 100 microM MPN of 24.9 (liver), 14.5 (esophagus), 7.0 (lung), and 0.0 to 2.7 (5 other tissues) pmol/mg/min. MPN depentylation by rat cytochrome P450 2A3 showed an apparent K(m) of 8 microM (V(max), 70 pmol/nmol of P450/min) and was competitively inhibited by the CYP2A inhibitor coumarin (apparent K(i), 4 microM). Coumarin (0.4 mM) inhibited microsomal depentylation of 100 microM MPN by 37 to 62% for human esophagus, liver, kidney, and colon and for rat esophagus but not for rat liver and lung. MPN depentylation by rat esophageal microsomes increased up to 90% on adding P450 reductase. The results indicate organ-specific MPN metabolism by rat but not human esophagus. Nevertheless, the relatively high activity of four human esophagi might indicate increased susceptibility of some individuals to carcinogenesis by unsymmetrical dialkylnitrosamines.

[Production of transgenic lamb integrated with modified human anti-trypsin gene]

This experiment is to produce the human mAAT(modified anti-trypsin) which cures the emphysema specifically through mammalian galactophore of transgenic goat. 56 goats were selected as donor for superovulation by FSF + LH microinjection in this experiment. The pronucleic embryos were injected with human mAAT gene after fertilization in vivo, and transferred to the donors or receptors directly. The superovulation was better in March and May than in December with the number of ovulation of 19.50, 21.70 and 16.06, and number of fertilized embryos of 4.31, 6.48 and 3.57 per-animal respectively. The pregnant rates were 18.18% and 25% respectively after transferred to donors and receptors with natural estrus. The donors also can be used as the embryo receptor with no remarkable decrease of pregnant rate. 29 lamb were labored. 4 positive transgenic lamb were checked by PCR, PCR-Southern and Southern analysis. The integrated efficiency of foreign DNA was 13.79% with microinjection of high copy number of foreign DNA fragment.

Transdifferentiation of human islet cells in a long-term culture

It has been established that ductal cells or precursor cells within the ductal tree of the pancreas can differentiate into islet cells. Although islet cells can also form exocrine cells, it is unclear whether they arise from precursor (stem) cells or from mature endocrine cells by transdifferentiation. Using a defined culture medium and technique for islet purification, for the first time we were able to maintain human islets in culture for more than a year. Multilabeling immunohistochemical and immunoelectron microscopic examination of the islets at different days of culture using islet cell markers (antibodies to hormones, neuron-specific enolase, chromogranin A) and ductal cell markers (cytokeratins 7 and 19, carbonic anhydrase II, DU-PAN2, CA 19-9, and MUC1) revealed that endocrine cells gradually transdifferentiate to ductal, acinar, and intermediary cells. Although islet hormone secretion ceased after day 28 in culture, endocrine cells were still detectable at day 60. However, later, all endocrine and exocrine cells were replaced by undifferentiated cells that expressed neuron-specific enolase, chromogranin A, laminin, vimentin, cytokeratin 7 and 19, alpha-1-antitrypsin, transforming growth factor-alpha, and epidermal growth factor receptor. Our data thus show that, under proper conditions, human islets can be maintained in vitro over a long period and that, in the culture condition, islet cells seem to transdifferentiate to exocrine cells and undifferentiated cells, which may be considered pancreatic precursor (stem) cells.

Synthesis and biological evaluation of didemnin photoaffinity analogues

The synthesis of four benzophenone-containing analogues of the antiproliferative natural product didemnin B is presented. In vitro protein biosynthesis inhibition potency and antitumor activity were evaluated. The results indicate that all four analogues are biologically active and could serve as photoaffinity reagents for the study of receptor-binding interactions of didemnins. These analogues could also be useful in studying antitumor effects of didemnins.

Indole can act as an extracellular signal in Escherichia coli

Previous work has shown that lacZ fusions to the cysK, astD, tnaB, and gabT genes in Escherichia coli are activated by self-produced extracellular signals. Using a combination of ethyl acetate extraction, reversed-phase C(18) chromatography, and thin-layer chromatography, we have purified an extracellular activating signal from E. coli supernatants. Mass spectrometry revealed a molecule with an m/z peak of 117, consistent with indole. Nuclear magnetic resonance analysis of the purified E. coli factor and synthetic indole revealed identical profiles. Using synthetic indole, a dose-dependent activation was observed with lacZ fusions to the gabT, astD, and tnaB genes. However, cysK::lacZ and several control fusions were not significantly activated by indole. Conditioned medium prepared from a tnaA (tryptophanase) mutant, deficient in indole production, supported 26 to 41% lower activation of the gabT and astD fusions. The residual level of activation may be due to a second activating signal. Activation of the tnaB::lacZ fusion was reduced by greater than 70% in conditioned medium from a tnaA mutant.

Design of near-infrared imaging probe with the assistance of ultrasound localization

A total of 364 optical source-detector pairs were deployed uniformly over a 9 cm x 9 cm probe area initially, and then the total pairs were reduced gradually to 60 in experimental and simulation studies. For each source-detector configuration, three-dimensional (3-D) images of a 1-cm-diameter absorber of different contrasts were reconstructed from the measurements made with a frequency-domain system. The results have shown that more than 160 source-detector pairs are needed to reconstruct the absorption coefficient to within 60% of the true value and appropriate spatial and contrast resolution. However, the error in target depth estimated from 3-D images was more than 1 cm in all source-detector configurations. With the a priori target depth information provided by ultrasound, the accuracy of the reconstructed absorption coefficient was improved by 15% and 30% on average, and the beam width was improved by 24% and 41% on average for high- and low-contrast cases, respectively. The speed of reconstruction was improved by ten times on average.

Mouse cyp2g1 gene: promoter structure and tissue-specific expression of a cyp2g1-lacz fusion gene in transgenic mice

The structure of the mouse Cyp2g1 gene was determined to identify regulatory regions important for its olfactory mucosa-specific expression. Two Cyp2g1 genomic clones were isolated and characterized. A 3.6-kilobase 5'-flanking sequence was used to prepare a Cyp2g1--LacZ fusion gene for transgenic mice production. Transgene expression, as determined by beta-galactosidase activity in tissue extracts, was detected in the olfactory mucosa, but not in any other tissues examined, in five different transgenic lines. Thus, the 3.6-kilobase fragment contained regulatory elements sufficient for olfactory mucosa-specific and proper developmental expression of the reporter gene. However, histological and immunohistochemical studies indicated that the expression of the transgene in the olfactory mucosa was patchy and the cellular expression patterns of the transgene did not exactly match that of the endogenous gene. These results implicate the presence of additional regulatory sequences that are necessary for the correct cell type-selectivity within the olfactory mucosa.

Retention behavior of transition metals on a bifunctional ion-exchange column with oxalic acid as eluent

The common eluents used with a bifunctional ion-exchange column (IonPac CS5A) for separating transition metals are pyridine-2,6-dicarboxylic acid and oxalic acid (Ox). When Ox is used, cadmium and manganese co-elute. Although much research has been done to overcome the Cd2+-Mn2+ co-elution problem, the role of lithium hydroxide in separating the transition metals has received little attention. In this study, it is found that when the Ox concentration is higher than 35 mM, Cu2+ elutes after Pb2+ and Ox plays a predominant role in the retention behavior of the seven metals. When Ox concentration is lower than 35 mM especially when its concentration (25 mM) is half of the usually used standard concentration (50 mM), Cu2+ elutes before Pb2+, and at the same time, Mn2+ and Cd2+ can also be baseline separated. Lithium hydroxide plays a predominant role in the separation of the metals separated by cation exchange. So, lithium hydroxide is used to adjust the pH of the eluent. The use of an isocratic elution (25 mM Ox/LiOH/2 mM Na2SO4, pH 3.88) allows the separation of seven metals (Cu2+, Pb2+, Co2+, Mn2+, Cd2+, Zn2+ and Ni2+) in a single run. The effects of inorganic modifiers such as NaNO3, Na2SO4 and Na4P3O7 on retention behavior of the metals are also investigated.

CYP1B1 expression in human lung

Cytochrome P450 1B1 is a recently recognized phase I bioactivating enzyme with high affinity for both inhaled tobacco carcinogens and 17beta-estradiol. We evaluated the human lung expression of this multifunctional member of the P450 superfamily across 16 individuals. Expression of CYP1B1 was evaluated by qualitative reverse transcription-polymerase chain reaction and Western immunoblots performed on human tumor and nontumor lung tissue. Expression at both mRNA and protein levels was then correlated with smoking history, plasma biomarkers of tobacco exposure (nicotine and cotinine), gender, and tumor histology. CYP1B1 mRNA and protein were detected in 94 and 100% of individuals, respectively. Multivariate analysis confirmed that there were more subjects displaying CYP1B1 mRNA expression in tumor than nontumor tissue (p = 0.0003). Correlation of CYP1B1 protein with plasma cotinine levels was statistically marginal (p = 0.027). Self-reported smoking history, gender, and tumor histology did not correlate with gene expression in the multivariate model. After multivariate modeling for confounding factors, the expression patterns of 5 of 16 individuals appeared to differ from the group as a whole for mRNA and/or protein. We conclude that CYP1B1 is commonly expressed in human lung and hypothesize that it may be an important phase I enzyme with respect to human lung carcinogen metabolism, warranting an understanding of regulatory control and coding region polymorphisms.

[Surgery treatment of retinal detachment with Marfan syndrome]

PURPOSE

To detect the reattachment rate and visual function outcome of Pars Plana Lensectomy, vitrectomy and scleral encircling (PPL + PPV + SE) to treat retinal detachment (RD) with Marfan syndrome.

METHODS

A retrospective study of 11 cases of 14 eyes with Marfan syndrome who submitted to PPL + PPV + SE.

RESULTS

All the cases were followed up for four - 46 months (means 31.2 months). Retinal reattachment rate was 85.7%, visual acuity were 0.3 or better in eight cases.

CONCLUSION

PPL + PPV + SE is a safe and effective treatment for retinal detachment with Marfan syndrome.

Mutations in the gene encoding lecithin retinol acyltransferase are associated with early-onset severe retinal dystrophy

The chromophore of the visual pigments, 11-cis retinal, is derived from vitamin A (all-trans retinol) through a series of reactions that take place in retinal pigment epithelium (RPE); (ref. 1). The first of these reactions is catalyzed by lecithin retinol acyltransferase (LRAT); (ref. 2). We screened 267 retinal dystrophy patients for mutations in LRAT and identified disease-associated mutations (S175R and 396delAA) in three individuals with severe, early-onset disease. We showed that the S175R mutant has no acyltransferase activity in transfected COS-7 cells. Our findings highlight the importance of genetic defects in vitamin A metabolism as causes of retinal dystrophies and extend prospects for retinoid replacement therapy in this group of diseases.

Hepatitis B virus genotype distribution among chronic hepatitis B virus carriers in Shanghai, China

OBJECTIVE

Hepatitis B virus (HBV) genotype distribution is still unclear in China, where a high prevalence of HBV infection exists, although it is well known that HBV can be classified into six genotypes based on intergroup divergence. The aim of this study was to investigate the epidemiological distribution of HBV genotypes and to clarify further the genotype-related differences in the pathogenicity of HBV.

METHODS

Seminested PCR and restriction fragment length polymorphism analysis were conducted in 97 asymptomatic HBV carriers (ASC) and 46 chronic hepatitis (CH), 37 liver cirrhosis (LC) and 44 hepatocellular carcinoma (HCC) patients in Shanghai, China.

RESULTS

Two hundred and twenty samples (98.2%) were positive for HBV DNA, and of these, 3 (1.4%), 38 (17.2%) and 179 (81.4%) were classified as genotype A, B and C, respectively. There was a statistically significant difference in the distribution of genotypes B and C among various categories of liver diseases (p < 0.01). The distribution of genotype C showed an increasing trend from ASC, CH and LC to the HCC group; in contrast, the distribution of genotype B showed a decreasing trend in the same order. HBeAg positivity was higher in genotype C than in genotype B in all the subjects or in the ASC group alone (p < 0.05, p < 0.01, respectively). More severe liver damage and a higher mean age were observed in genotype C than in genotype B (p < 0.01, p < 0.05, respectively).

CONCLUSIONS

These results indicate the following: (1) genotypes A, B and C of HBV exist in Shanghai, China; (2) genotype C is the major genotype in this area; (3) genotype C is associated with the development of severe liver diseases, and (4) genotype B has a relatively good prognosis.

Molecular regulation of genes encoding xenobiotic-metabolizing enzymes: mechanisms involving endogenous factors

It is widely recognized that xenobiotic-metabolizing enzymes play a fundamental role in the basic processes of carcinogenesis and toxicity on one hand, and chemoprevention and drug efficacy on the other. Realization that different factors can profoundly affect the expression of these enzymes at the genome level has resulted in an enhanced appreciation of the importance these genes play in our modern industrialized age. There continues to be rapid proliferation of studies addressing the molecular regulation of these genes. The discovery of common signal transduction pathways and transcription factors that dictate tissue and developmental-specific expression, as well as variation in expression within a given tissue, suggest that there may be significant interaction among these various regulatory systems. This report is a summary of a symposium that was part of the Structure, Function and Regulation of Cytochromes P450 and Xenobiotic Metabolizing Enzymes satellite meeting of the 2000 joint meeting of the American Society for Biochemistry and Molecular Biology, the American Society for Pharmacology and Experimental Therapeutics, the French Pharmacological Society, and the Pharmacological Society of Canada held in Boston, Massachusetts. This symposium brought together several speakers who addressed specific receptor-mediated signal transduction pathways involved in the regulation of xenobiotic-metabolizing enzymes, as well as other molecular mechanisms whereby endogenous factors are involved in controlling tissue- and developmental-specific expression.

Signal peptide-selection of cDNA cloned directly from the esophageal gland cells of the soybean cyst nematode Heterodera glycines

Secretions from the esophageal gland cells of plant-parasitic nematodes play critical roles in the nematode-parasitic cycle. A novel method to isolate cDNA encoding putative nematode secretory proteins was developed that utilizes mRNA for reverse transcription-polymerase chain reaction derived from microaspiration of the esophageal gland cell contents of parasitic stages of the soybean cyst nematode Heterodera glycines. The resulting H. glycines gland cell cDNA was cloned into the pRK18 vector, and plasmid DNA was transformed into a mutated yeast host for specific selection of cDNA inserts that encode proteins with functional signal peptides. Of the 223 cDNA clones recovered from selection in yeast, 97% of the clones encoded a predicted signal peptide. Fourteen unique cDNA clones hybridized to genomic DNA of H. glycines on Southern blots and, among them, nine cDNA clones encoded putative extracellular proteins, as predicted by PSORT II computer analysis. Four cDNA clones hybridized to transcripts within the dorsal esophageal gland cell of parasitic stages of H. glycines, and in situ hybridization within H. glycines was not detected for eight cDNA clones. The protocol provides a direct means to isolate potential plant-parasitic nematode esophageal gland secretory protein genes.

Role of SspA in the density-dependent expression of the transcriptional activator AarP in Providencia stuartii

The AarP protein in Providencia stuartii encodes a small transcriptional activator which activates the chromosomal aminoglycoside acetyltransferase aac(2')-Ia gene. In addition, AarP activates genes involved in a multiple antibiotic resistance (Mar) phenotype. Expression of an aarP-lacZ fusion increased in a density-dependent manner and reached peak levels at stationary phase. The expression of an aarP-lacZ fusion could be prematurely activated in cells at early to mid-exponential phase by the addition of spent culture supernatants from stationary phase cultures or by ethyl acetate extracts of these supernatants. Nutrient starvation had a negligible effect on aarP expression. In a search for mutations that block aarP activation at stationary phase, a mini-Tn5Cm insertion has been identified within a gene whose product was 77% identical to SspA, a regulatory protein involved in stationary phase gene expression and virulence. An unmarked sspA null allele (sspA2) was created by allelic replacement to further examine the role of sspA in P. stuartii. The sspA2 allele resulted in substantial decrease in aarP mRNA accumulation at various phases of growth. Furthermore, in an sspA mutant background, the aarP-lacZ fusion was no longer activated by an extracellular signal.

Experiment study of effect of perfluorohexyloctane on corneal endothelial cells

PURPOSE

To investigate the effect of Perfluorohexyloctane (F6H8) on corneal endothelial cells(CEC) of rabbit eyes.

METHODS

Fifteen New Zealand white rabbits were divided into two groups: experimental group(F6H8) and control group(BSS). All rabbits underwent anterior chamber injection of 0.15 ml F6H8 or BSS. Slit-lamp biomicroscopy and corneal endothelium photography were performed pre-operatively and postoperatively. Histopathological examination and Transmission electron microscopy(TEM) were done after the rabbits were sacrificed.

RESULTS

All the corneas were clear. Since 4 weeks after operation, the endothelial cells were markedly irregular in size and shape and the number of endothelial cells was markedly decreased. Multilayered retrocorneal membranes(RCM) grew gradually 2 weeks after surgery. Vacuolar degeneration was seen in some endothelial cells. Nuclear degeneration and edema of plasma were seen in TEM.

CONCLUSION

Corneal endothelial cell degenerated after contacting with F6H8 for 2-4 weeks. As a silicone solvent, it should be removed completely after injection. We don't recommend it to be used as a new intraocular temponade.

Electrochemical characteristics of thin nickel hexacyanoferrate films formed on gold and thiol self-assembled monolayers modified gold electrodes

Nickel hexacyanoferrate (NiHCF) film was prepared and characterized on gold and thiol self-assembled monolayers (SAMs)-modified gold electrodes. It was found that the film exhibited some different electrochemical characteristics compared with that found on a carbon electrode. In the presence of K+, the film exhibited a redox peak at about 0.5 V. The peak potential shifted linearly with the K+ concentration over the range of about 0.1 mM - 0.1 M with slopes of 54 - 60 mV per log[K+]. However, in solutions containing Na+, Li+ or NH4+ ion the film did not generate well-defined peaks, or even a visible redox peak. Therefore, the film showed a selective potential response to K+. The voltammetric behavior of NiHCF film varied with thiols, the preparation procedure and the solution pH. Under certain conditions, the characteristics of the film could be improved to some extent.

[Role of substance P in pressor response of nucleus ventromedialis to glutamate]

AIM

To analyze mechanism underlying pressor response of the nucleus ventromedialis (NVM) to glutamate.

METHODS

Effects of different drugs delivered by intra-brain or i.v. injections on blood pressure and heart rate were observed in rats.

RESULTS

(1) Excitation of the NVM by L-glutamate (Glu), injection of substance P (SP) into the nucleus dorsomedialis (NDM), nucleus paraventricularis (NPV) or rostral ventrolateral medulla (RVL), all induced pressor responses. (2) NVM pressor responses could be attenuated by preinjection of [D-Pro2, D-Phe7, D-Trp9]-SP (DPDPDT, a substance P antagonist) bilaterally into the NDM, NPV or RVL, but preinjection of atropine into the RVL had no such effect. (3) Phentolamine (i.v. ) also reduced the NVM pressor response, but propranolol or methyl atropine (i.v.) had no significant effect.

CONCLUSION

The NVM SPergic neurons can activate NDM SPergic neurons, which proceed to excite the NPV pressor area (SP receptor) and RVL (SP receptor)-sympathetic vasoconstrictor nerve system, thereby induce pressor response. The cardiac sympathetic and cardiac vagal nerves are not involved in this response.

[Evaluation of p53, p21waf1, and PCNA in the diagnosis on lung cancer]

OBJECTIVE

To evaluate the diagnostic value of p53, p21waf1 and PCNA on diagnosis of lung cancer.

METHODS

One hundred and fourteen lung cancer patients and 89 cases with benign pulmonary diseases were studied on the expression of p53, p21waf1 and PCNA by immunohistochemical staining. The differences of p53, p21waf1 and PCNA expression status between these two groups were compared and the diagnostic value of these three markers was evaluated.

RESULTS

(1) The positive rates of p53, p21waf1 and PCNA expression in lung cancer were 47.37%, 75.44% and 80.70%, all significantly higher than that in benign pulmonary diseases (P < 0.001), with odds ratio 39.15, 5.75, 6.76 respectively. (2) The positive likelihood ratio of p53 was 21.08, higher than that of p21waf1 and PCNA. Specificity and Youden index were also higher than those of p21waf1 and PCNA, but the sensitivity of p53 was low. (3) The sensitivity and specificity of p53 and PCNA parallel test were 89.47% and 60.67% respectively.

CONCLUSIONS

(1) The expression of p53, p21waf1 and PCNA in lung cancer cases were all upregulated. These three markers all seemed to have strong links with lung cancer. (2) p53 was shown a good marker for lung cancer diagnosis. (3) The diagnostic value of p53 and PCNA parallel test was rather high.

Structure--activity relationships of side-chain modified didemnins

The synthesis and antitumor activity of a novel didemnin B analogue containing a psi[CH2NH] amide bond surrogate between N-Me-D-Leu7 and Pro8 are reported. The analogue shows activity (GI50 = 4 nM) comparable to that of didemnin B (GI50 = 13 nM) in the NCI-60 tumor cell screen. This result, along with new data from previously reported synthetic didemnin analogues, is discussed within the context of the side-chain SAR for didemnins.

[Lys3]Didemnins as potential affinity ligands

The synthesis and biological activity of N(epsilon)-Z-[Lys3]didemnin B are reported. This novel analogue retains antiproliferative, cytotoxic, and protein biosynthesis inhibition activities, but at reduced levels. This result suggests the use of [Lys3]didemnin derivatives as potential affinity probes for studying the molecular target(s) of the didemnin class of natural products.

Hypotensive and physiological effect of angiotensin converting enzyme inhibitory peptides derived from soy protein on spontaneously hypertensive rats

Angiotensin converting enzyme (ACE) inhibitory peptides prepared from soy protein by the action of alcalase enzyme was tested for its hypotensive effect on spontaneously hypertensive rats (SHR). Captopril, an ACE inhibitor used widely for hypertension treatment, was also applied in comparison. A significant (p < 0.05) decrease in systolic blood pressure of SHR was observed when soy ACE inhibitory peptides were orally administrated at three different dose levels (100, 500, and 1000 mg/kg of body weight/day), whereas little change occurred in the blood pressure of normotensive rats even at the highest dose. After a month-long feeding, blood pressure readings of SHR fell by approximately 38 mmHg from the original level at the lowest dose; a steadily and progressively hypotensive effect existed for these soy ACE inhibitory peptides administration groups. An obvious fluctuation was observed at the third week, although Captopril had a stronger hypotensive effect. The ACE activity of serum, aorta and lung, and lipid content of serum of SHR upon administration of soy ACE inhibitory peptides did not show a significant difference from that of the control group, whereas the serum ACE activity increased and the aorta ACE activity decreased significantly (p < 0.05) for the Captopril group. Serum Na(+) concentration decreased significantly in both the peptides-treated groups and the Captopril-treated group in comparison with the control group, whereas no lowering effect was observed for serum K(+) and serum Ca(2+) concentrations. These results suggested that the hypotensive effect of ACE inhibitory peptides derived from soy protein could be at least partly attributed to the action on salt/water balance.

Identification of a new human CYP2A gene fragment with close linkage to CYP2GP1

Human genomic libraries were screened to identify CYP2G-related cytochrome P450 genes. A genomic fragment comprising exons 7 through 9 of CYP2GP1 and exons 6 through 9 of a previously unidentified CYP2A gene, designated CYP2A7P2, was isolated from an EMBL3 library; the two genes were arranged in outward opposite directions with about 8 kbp of intervening sequence. The same structure was also detected in a bacteriophage P1 clone, which contained a full-length CYP2GP1 gene, exons 6 through 9 of CYP2A7P2, and the CYP2B7 gene. However, additional CYP2A-related exons as well as other CYP2A genes, CYP2A7P1, CYP2B6, CYP2F1, and CYP2GP2 were not detected. These results indicate that CYP2A7P2 is located near CYP2B7 in the middle of the CYP2A-2B-2F gene cluster on chromosome 19. Furthermore, an analysis of CYP2A sequence alignment suggests that CYP2A7P2 may be derived from the same ancestral gene that gave rise to CYP2A7P1, which was corrupted by a large insertion at intron 5.

Effects of long-term infusion of anorexic concentrations of islet amyloid polypeptide on neurotransmitters and neuropeptides in rat brain

Islet amyloid polypeptide (IAPP or amylin) potently reduces food intake in rats at or near physiological concentrations. Although the mechanisms of action of IAPP are not understood, the brain is a suggested site. Changes in hypothalamic and striatal neurotransmission have been reported following acute systemic administration of a pharmacological concentration of IAPP. In the current study, we evaluated the effects of chronic administration of low doses of IAPP on satiety-related neurotransmitters and neuropeptides in the hypothalamus, hippocampus, striatum, left cortex, and right cortex of the rat. Doses of 0, 5 and 25 pmol IAPP/kg-min were administered subcutaneously for 2 or 5 days. Food intake was reduced by 27 and 44% (both P<0.001) for the 5 and 25 pmol/kg-min groups, respectively, in the 2-day experiment and was decreased by 14% (P<0.01) and 24% (P<0.001), respectively, in the 5-day experiment. Body weight was significantly decreased in a dose-dependent fashion. In the 2-day experiment, norepinephrine increased in the hypothalamus in the 5 pmol IAPP/kg-min group, and neurotensin increased in the hippocampus in the 25 pmol/kg-min rats (both P<0.05). In the 5-day, 5 pmol/kg-min rats, 5-hydroxyindoleacetic acid (5-HIAA) increased in the hypothalmus and cholecystokinin (CCK) increased in the striatum (both P<0.05). In the 5-day, 25 pmol/kg-min group, neuropeptide Y (NPY) increased in the hypothalamus (P<0.01) and CCK increased in the hypothalmus and striatum (both P<0.05). The present study confirms that IAPP is a potent anorectic peptide at low doses and suggests that IAPP not only affects classical neurotransmitters in the brain but also alters concentrations of neuropeptides known to be involved in food intake.

Maintenance of human islets in long-term culture

The long-term maintenance of human islets in culture has remained a challenge. Despite advancements in culture techniques, human islets proved to have a short life span in vitro. For the first time, we have succeeded in maintaining human islets in a defined culture medium for more than 12 months. Freshly isolated islets from a 38-year-old donor were cultured in M3:5 medium and placed on a rocker for 14 days to remove contaminated exocrine and mesenchymal cells which attached to the bottom. The floating islets were purified by daily hand-picking and transfer into fresh medium. After 14 days, purified islets were allowed to attach to the bottom of the flasks and to expand. At various time points, islets were examined immunohistochemically and electron microscopically, and the secretion of islet hormones and their mRNA were determined by radioimmunoassay and reverse transcriptase polymerase chain reaction, respectively. Within seven days of culture, ductular and acinar cells developed within the initially normal islets. With time, exocrine cell types expanded while the number of the endocrine cells and their secretion decreased. At day 60, only a few endocrine cells were identifiable, whereas most of the cells appeared undifferentiated and expressed cytokeratin 7 and 19, neuron specific enolase, tomato lectin, phaseolus leucoagglutinin, laminin, and vimentin. After 60 days, the culture consisted entirely of undifferentiated cells which could be maintained in culture for 270 days before they became senescent. This is the first report on the long-term maintenance of human islet cells in culture and allows an insight into the complex process of endocrine cell differentiation.

Ion chromatographic analysis of tetracyclines using polymeric column and acidic eluent

High-performance ion chromatography (HPIC) is first successfully used to analyze tetracycline antibiotics (TCs) in this work. The TCs are well separated on a solvent compatible polymeric cation-exchange column within 12 min. Isocratic elution with acetonitrile-hydrochloride is very advantageous for routine analysis. HPIC may be seen as a specific variant of the more common high-performance liquid chromatography (HPLC) for water-soluble and polar pharmaceuticals with low hydrophobicity. The detection limits (signal-to-noise ratio=3:1) of oxytetracycline (OTC), tetracycline (TC), chlortetracycline (CTC), doxycycline (DC) are 10, 10, 20 and 20 microg l(-1), respectively. Samples are prepared by vortex mixing with an ethylenediaminetetraacetic acid disodium salt (Na2EDTA)-McIlvaine buffer (pH 4.0) solution and the mixture filtrates through a molecular weight cut-off filter. The method has been successfully applied to monitor the OTC removal rate through every reactor in the process of OTC manufacturing wastewater treatment by bio-chemical technology. It is also applicable to determine the TCs residues in milk and milk powder with satisfying results.