[Environmental pollution, human exposure and its health effect of sodium pentachlorophenate in schistosomiasis prevalent area]

Sodium pentachlorophenate (Na-PCP) has been used in China for years as an molluscacide to kill oncomelania, which is an intermediate host of Schistosome. To evaluate the effects of its long-term successive usage on environment, human exposure and health, studies were carried out in Sichuan, Jiangxi, Jiangsu and Fujian provinces, with a time gap of more than one month between sample collection and last spray of Na-PCP. Results indicated that PCP contents in surface water, soil, sediment, animals and plants were significantly higher in studied areas than in control areas. The daily intake and the content in urine of PCP were also sigificantify higher in studied areas. But, there was no difference on physical and biochemical examinations except that a 22%-28% decrease of blood cholinesterase activity was found in studied areas. The health effect of impurities in Na-PCP, dioxins and furans, was assessed and discussed.

[Renin-angiotension system--stress hormone response system]

Angiotensin II (A II) was significantly increased in both acutely and chronically stressed animals as found in brain, heart, blood vessels and adrenal glands. After running a race, the plasma A II contents of sportsmen similar to cortisol increased markedly too. In the chronical stress-hypertensive animals, the contents of circulating A II and tissue A II were increased quite lastingly. It was also found that the high concentration of A II may stimulate the adrenal gland secreting glucosteroid, and increase of tissue A II may be faciliated by the activation of beta adrenergic receptors. On basis of the above finding, we tend to assume that A II is a stress hormone and the renin angiotension system (RAS) is a stress hormone responses system. Morever there exists a close relation between RAS and two classic stress hormone response systems, i.e. the hypothalamus-pituitary-adrenal cortex system and the sympathetic-adrenal medulla system.

An improved green fluorescent protein gene as a vital marker in plants

A synthetic green fluorescent protein (GFP) gene (pgfp) was constructed to improve GFP expression in plants. Corn and tobacco protoplast transient assays showed that pgfp gave about 20-fold brighter fluorescence than the wild-type gene (gfp). Replacement of the serine at position 65 with a threonine (S65Tpgfp) or a cysteine (S65Cpgfp) yielded 100- to 120-fold brighter fluorescence than wild-type gfp upon excitation with 490-nm light. Incorporation of a plant intron into the coding region yielded an additional 1.4-fold improvement, for a cumulative improvement of about 150-fold in fluorescence at 490-nm excitation. Various versions of pgfp were also stably introduced into corn, wheat, tobacco, and Arabidopsis plants. Bright-green fluorescence was observed with a fluorescence microscope in virtually all examined tissues of transgenic monocots and dicots. In the case of Arabidopsis, expression of the pgfp gene under the enhanced 355 promoter of the cauliflower mosaic virus produced green fluorescence that was readily detectable by eye using a hand-held, long-wave ultraviolet lamp and/or a black-light source.

Adenoviral gene transfer of macrophage inflammatory protein-2 in rat lung

Replication-defective adenoviral vectors are capable of localized transfer and expression of incorporated gene product in lung tissue. We have constructed an adenoviral vector that expresses rat macrophage inflammatory protein (MIP)-2, a C-X-C chemokine specifically chemotactic for neutrophils, Supernatants from 293 cells, infected with the adenoviral MIP-2 (ADMIP-2) construct, showed potent chemotactic activity and the ability of the ADMIP-2 vector to transcribe and make functional protein was confirmed. In vivo analysis of bronchoalveolar lavage fluid from rats after intratracheal instillation of ADMIP-2 (10(9) plaque-forming units) showed a 10-fold increase in the absolute number of neutrophils in bronchoalveolar lavage fluid as opposed to rats treated with an equal titer of an E1-disabled control virus expressing firefly luciferase (ADCA-18). Neutrophils constituted 65% of total BAL cells with alveolar macrophages being the other major cell type recovered. Rat MIP-2 protein was increased (nanograms per milliliter) in bronchoalveolar lavage fluid over a period of 7 days in ADMIP-2-treated animals. MIP-2 mRNA was demonstrated by Northern blot analysis in lung tissue, and histological analysis confirmed the presence of massive localized tissue neutrophilia. Evidence of chronic tissue injury and repair (ie, fibrosis) was not detected up to 2 weeks after the neutrophil infiltrate had resolved, subsequent to decreased chemokine presence. Adenoviral gene transfer proved an effective tool for the assessment of lung tissue expression of this chemokine in vivo and is useful in developing rodent models of tissue neutrophilia.

[Research progress on the glia cell line-derived neurotrophic factor]

Glia cell line-derived neurotrophic factor (GDNF) is a novel type of neurotrophic factor cloned in 1993. Recent research revealed that it may have potential application in the treatment of Parkinson's disease and motor neuron diseases. This short review summarized the character of the protein, gene structure, tissue distribution, and its physiological functions and pathological implications.

Purification and identification of ABA-binding proteins and antibody preparation

Maize root membranes were extracted and the solubilized proteins were affinity-purified using an ABA-BSA-Sepharose 4B matrix. The retained proteins were eluted with 4M urea or 10(-4)M ABA. ABA could elute the binding proteins but other phytohormones, such as IAA or GA3, could not. ABA binding activity was detected in ABA- and urea-elute fractions using competitive ELISA block tests and [3H]ABA binding assays. Scatchard analysis showed an apparent K(d) of 4.8 nM for the ABA binding activity of the protein. When ABA or urea eluate was loaded on a concanavalin-A-Sepharose column, the fraction eluted with 0.2 M methyl alpha-mannopyranoside still showed ABA binding activity, suggesting that ABA binding proteins are glycoproteins. Polyclonal antibodies against ABA binding proteins were raised using as immunogen ABA or urea eluate from the ABA-BSA-Sepharose column. The resulting antibodies not only recognized 56 kDa binding proteins but also blocked the binding of ABA to an ABA-specific antibody, indicating properties similar to anti-idiotypic antibodies. The purified antibodies will be suitable to purify and characterize putative ABA receptors.

[Loss of heterozygosity involving DCC gene in human colorectal cancers is correlated with the metastatic potential]

DCC gene located at chromosome 18q21.3 is an important tumor-supressor gene associated with tumorigenesis and progression, especially in colorectal carcinomas. Adopting Southern blot technique and RFLP analysis, 33 primary Chinese colorectal cancer patients were examined for loss of heterozygosity (LOH) of DCC gene. Among 16 informative cases, 6 (38%) showed allelic deletion. 18q LOH was correlated with lymph node and hepatic metastases (P < 0.05). The results indicate that application of molecular genetics is of value in ascertaining the metastatic potential of colorectal carcinomas.

Tyrosine kinases in activation of the MAP kinase cascade by G-protein-coupled receptors

The mitogen-activated protein kinase (MAPK) signalling cascade is a prominent cellular pathway used by many growth factors, hormones and neurotransmitters to regulate physiological responses. Although activation of the MAPK pathway by receptors with tyrosine kinase activity is well defined, the mechanism used by heterotrimeric G-protein-coupled receptors to activate this pathway is less clear. Here we show that in cells deficient in the Src-related tyrosine kinase Lyn, stimulation of MAPK kinase and MARPK by Gq-coupled m1 muscarinic acetylcholine receptors (mAChR) is blocked, whereas Gi-coupled m2 mAChR-mediated stimulation is unaffected. In cells deficient in the tyrosine kinase Syk, both m1 and m2 mAChRs failed to stimulate MAPK kinase and MAPK. This result indicates that Syk is essential for the Gi-coupled pathway and that Lyn and Syk are necessary for the Gq-coupled pathway.

Factors accounting for different responses of pulmonary and cerebral vessels to hypoxia

The roles of sympathicus, sensory neuropeptides (SNP), cyclooxygenase metabolites (COX-M), lipoxygenase metabolites (LOX-M), endothelium derived relaxing factor (EDRF), reactive oxygen (ROS) and potassium channels (PC) in the hypoxic pulmonary vasoconstriction (HPV) and hypoxic cerebral vasodilation (HCVD) were investigated in intact rats, rabbits and dogs. The results showed that during hypoxia, the excitation of sympathicus caused a constriction of both pulmonary and cerebral vessels, while SNP, EDRF and the opening of voltage sensitive PC caused the dilation of both of them; LOX-M mediated HPV and HCVD, COX-M might serve as their modulators; the blockade of ATP sensitive PC induced by hypoxia mediated HPV, but had no effect on HCVD; the reduction of O2-. in the lung might potentiate HPV, however, O2-. remained unchanged in brain during hypoxia. It is suggested that the alterations of LOX-M, ROS and the ATP sensitive PC are the factors accounting for the difference in the response of pulmonary and cerebral vessels to hypoxia.

Angiotensin II--an important stress hormone

Angiotensin II (Ang II) is an important stress hormone. Circulating and tissue Ang II are significantly increased in both acutely and chronically stressed animals. In humans, the plasma Ang II content increases markedly after sprinting, as does cortisol. The present paper reviews recent studies with special reference to the correlation between the renin-angiotensin system (RAS) and the hypothalamus-pituitary-adrenal cortex system and sympathetic-adrenal medulla system during stress. We would like to suggest that in the stress response, Ang II is not only a stress hormone to various peripheral organs, but is also a notable factor in initiating the systemic stress response from central to peripheral tissues. The RAS is therefore a stress hormone response system similar to the hypothalamus-pituitary-adrenal cortex system and the sympathetic-adrenal medulla system.

Identification of donor-derived dendritic cell progenitors in bone marrow of spontaneously tolerant liver allograft recipients

Multilineage donor-derived hematopoietic cell chimerism is a persistent feature of spontaneously tolerant mouse liver allograft recipients. We have shown previously that normal liver-derived precursors of "chimeric" dendritic cells (DC) propagated in vitro migrate in vivo to T-dependent areas of allogeneic lymphoid tissue, where they or their progeny appear to persist indefinitely. In this study, granulocyte-macrophage colony-stimulating factor (GM-CSF)+interleukin-4 (IL-4) were used to propagate DC progenitors from freshly isolated mouse bone marrow. The progenitor cells gave rise in 7-10 days to potent antigen-presenting cells (APC) that stimulated naive allogeneic T cells in primary mixed leukocyte cultures (MLC). The culture method, together with the reverse transcriptase-polymerase chain reaction (RT-PCR) for the detection of donor and recipient strain major histocompatibility complex (MHC) class II mRNA was used to test whether donor-derived DC could be propagated from the bone marrow of unmodified, orthotopic liver allograft recipients. Freshly isolated bone marrow from these transplanted animals contained small numbers of donor cells and responded to GM-CSF+IL-4 stimulation. In addition to cells expressing recipient (B10) phenotype (H-2Kb+; Iab+), a minor population of donor (B10.BR)-derived cells (H-2Kk+; Iak) were also propagated from liver graft recipients euthanized two weeks posttransplant. DC sorted from these cultures exhibited stimulatory activity for recipient strain T cells consistent with a low level (< 1%) of donor DC propagation. The immunologic role of donor-derived DC progenitors in liver allograft recipients and its relation to the induction and maintenance of donor-specific unresponsiveness remains to be determined.

[Significance of diagnosis and prognosis for breast carcinoma with examination of Ag-NORs]

The argyrophilic nucleolar organizer regions (Ag-NORs) was measured in the tissue sample aspirated with fine needle for 17 cases of breast benign lesion and 46 cases of breast cancer, by analysis of their micro-image with light microscope and computed. The results indicated that the amount of Ag-NORs in the nuclei of breast cancer was increased while the percentage of average areas occupied by Ag-NORs was decreased. It was significant statistically in comparing with benign lesion (P < 0.05). In addition, the amount of Ag-NORs in the nuclei of breast cancer with and that without metastasis was not different markedly (P > 0.05). However the percentage of average areas occupied by Ag-NORs was different statistically (P < 0.05). The conclusion of Ag-NORs is of benefit to distinguish from benign and malignant tumours of breast as well as significant for evaluating the prognosis for breast cancer.

Activation of Tsk and Btk tyrosine kinases by G protein beta gamma subunits

Tsk/Itk and Btk are members of the pleckstrin-homology (PH) domain-containing tyrosine kinase family. The PH domain has been demonstrated to be able to interact with beta gamma subunits of heterotrimeric guanine nucleotide-binding proteins (G proteins) (G beta gamma) and phospholipids. Using cotransfection assays, we show here that the kinase activities of Tsk and Btk are stimulated by certain G beta gamma subunits. Furthermore, using an in vitro reconstitution assay with purified bovine brain G beta gamma subunits and the immunoprecipitated Tsk, we find that Tsk kinase activity is increased by G beta gamma subunits and another membrane factor(s). These results indicate that this family of tyrosine kinases could be an effector of heterotrimeric G proteins.

[p53 gene point mutation in human colorectal carcinoma]

We introduced two modified assay systems, PCR-SSCP and PCR-direct sequencing for the identification of structure aberration at p53 exon 7 in 22 colorectal carcinomas and 1 metastatic lymph node. The data indicated that 27.2% (6/22) colorectal carcinomas and one metastatic lymph node were shown to contain the point mutations in codons 245, 251, 259 and 260 of exon 7. One half of all the mutations was G:c to A:T transition in codon 245. Other mutation patterns were base insertion and deletion. All positive point mutations of p53 exon 7 existed in colon carcinomas in this study. The point mutation in p53 exon 7 was usually associated with poorly differentiated primary carcinomas (P = 0.0178) and the mutation rate of was higher in Duckes C stage of the disease than in stage Duckes A and B (P = 0.0361). Thus p53 exon 7 point mutation in primary colorectal tumors and regional lymph nodes may identity a subgroup of colorectal cancer patients with more aggressive disease and may be as a new tumor markers for assessing the prognosis of colorectal carcinomas.

[Total pelvic exenteration for local advanced rectal carcinoma: analysis of 20 patients]

20 patients of total pelvic extenteration (TPE) were performed from 1989 to 1995 for local advanced rectal carcinoma. The incidence of operative complications was 65% with a mortality of 5%. 19 patients were followed up for 3-42 months, 7 patients died with an average life-span of 14.1 months. It seemed to us that the results of conservative therapy was usually disappointing for local advanced rectal carcinoma and and TPE is the better management of choice for relieving patient's symptoms and improving their survival rates.

Role of lipopolysaccharide (LPS), interleukin-1, interleukin-6, tumor necrosis factor, and dexamethasone in regulation of LPS-binding protein expression in normal hepatocytes and hepatocytes from LPS-treated rats

Lipopolysaccharide (LPS)-binding protein (LBP) has been reported to be an acute-phase protein. LBP binds to LPS with a high affinity; LPS-LBP complexes then interact with the receptor CD14, resulting in increased expression of LPS-inducible genes. Hepatocytes represent a major source of LBP, but little is known about the regulation of rodent hepatocyte LBP synthesis. In these studies, undertaken to characterize hepatocyte LBP expression, we show that greater-than-20-fold increases in LBP mRNA levels in hepatocytes occurred following injection of LPS or turpentine in rats. In primary cultures of rat hepatocytes, the addition of interleukin-6 (IL-6) and LPS led to 4.5- and 3.2-fold stimulation in LBP mRNA levels, respectively. The induction of LBP by IL-6 or LPS was attenuated by dexamethasone. In contrast to IL-6 and LPS, in the presence of 10(-6) M dexamethasone, IL-1 and tumor necrosis factor (TNF) led to maximal LBP mRNA induction levels, 4.7- and 3.8-fold, respectively, suggesting that IL-6 and LPS stimulate LBP expression by mechanisms different from those of IL-1 and TNF. Similar induction levels of LBP mRNA were seen in rat H35 hepatoma cells for all four stimuli, and dexamethasone inhibited these responses. Dexamethasone alone increased the spontaneous induction in primary hepatocytes at early time points but suppressed induction at later time points. Furthermore, hepatocytes from rats treated with LPS in vivo exhibited a > 10-fold increase in mRNA expression in response to LPS and enhanced responses to TNF and IL-1. As with the normal hepatocytes, dexamethasone inhibited the LPS-dependent induction in the LPS-treated rat hepatocytes. These data suggest that LBP synthesis by hepatocytes is under the control of LPS, IL-1, TNF, IL-6, and glucocorticoids and that the LPS treatment primes hepatocytes for subsequent responses to LPS, TNF, and IL-1 for LBP synthesis.

[The diagnosis and treatment of focalized pancreatitis: report of 16 cases]

We report 16 patients of focalized pancreatitis. All patients presented mass in the head of pancreas and obstructive jaundice (13 patients), characterized by spontaneous mass shrinkage and jaundice subsidence within two weeks after admission without any surgical intervention. Sonography, ERCP, exploration and intraoperative biopsy are of value in differentiating FP from carcinoma. Six patients received conservative therapy. Operations aimed to drain the commonbile duct and pancreatic duct (T tube drainage of commonbile duct, choledochojejunostomy, pancretojejunostomy) were performed in 7 patients. Pancretoduodenectomy were performed in 3 patients on tentative diagnosis of carcinoma in the head of the pancreas. Follow-up in 12 patients showed satisfactory results.

Differences in colorectal cancer between China and Japan: a clinical and histological study of two groups of cases

It is well known that most tumours are attributed to life style, especially the tumours of the digestive system. Clinical and histopathological investigation of tumours in different human groups and societies, and analysis of the variations will provide evidence for this, and is one of the approaches to study carcinogens. Clinical data obtained from 391 patients with colorectal cancer at the Sakai Municipal Hospital, Japan, and Shanghai Jinshan Hospital and Cancer Hospital, China, from 1987 to 1992, included the sex, age and tumour subsite. Sections of histological specimens were also retrieved. The results were compared between two countries. The average age of patients with colorectal cancer in Shanghai was 8.5 years less than in the Sakai group. The age peak of the former was 51-60, and in the latter, 61-70 years. The most frequent site of the cancer in the Shanghai group was the rectum, contrasting with the higher percentage of sigmoid colon cancer in Sakai group. There was also a significant difference in histological subtype of the cancer between the two groups. Mucinous adenocarcinoma was notably more common in the Shanghai group than in the Sakai group, and the high frequency was mainly in the colon. All of the variations were suggested to be attributable to differing socioeconomic circumstances and lifestyle, especially the dietary habits of the countries.

Linear aggregations of stomata and epidermal cells in Tradescantia leaves: evidence for their group patterning as a function of the cell cycle

We tested Charlton's hypothesis (1990) that stomata are present and patterned in linear cell aggregations using the monocot Tradescantia. We examined the following features of the leaf epidermis in support of this theory: linear groups (strings) of stomatal complexes and of epidermal cells were sought in immature and mature regions of entire leaves; the lengths (in cell number) and incidences (numerical occurrence) of both string types were determined; the uniformity and progression of stomatal differentiation within strings were studied; physical characteristics of differentiating strings within cell files were measured. Undifferentiated epidermal cells from the leaf base were stained with DAPI to reveal precursors of stomatal strings immediately proximal to the stomatal initial region. The results indicated that the Tradescantia epidermis in the leaf blade consists of linear groups of stomata and epidermal cells, which did not change in cell number nor incidence during development. The incidence of stomata by length was nonrandom. Although incidence decreased with string length, the decline was not linear nor exponential. Stomatal strings show cell cycle synchrony in DAPI staining of stomatal precursors and synchrony of stomatal differentiation within a string. The irregularity in the length of the stomatal development region, and each differentiation stage in it, by cell file was consistent with the variation in string length and unity in string development. The evidence supports Charlton's hypothesis that cells are patterned based on their position in the cell cycle and that linear groups of stomata reflect cell lineages, which maintain a degree of cell cycle synchrony.

Remote tissue injury primes hepatocytes for nitric oxide synthesis

Following trauma and tissue injury, patients frequently suffer infections and septic complications. Tissue injury is associated with the induction of the hepatic acute-phase response, but how this phenotypic expression by hepatocytes influences their subsequent response to endotoxin (lipopolysaccharide, LPS) or inflammatory cytokines is unknown. We have shown that both rat and human hepatocytes maximally express the enzyme-inducible nitric oxide synthase (iNOS) in response to a combination of LPS and the cytokines tumor necrosis factor (TNF), interferon-gamma (IFN-gamma), and interleukin-1. Furthermore, we have shown that the in vivo induction of the acute-phase response following tissue injury (hind limb turpentine injection) is not associated with hepatocyte iNOS expression. In this study, we show that the phenotypic change associated with the acute-phase response following tissue injury primes the hepatocyte to subsequently express iNOS in vitro in response to LPS alone as well as TNF and IFN-gamma. This expression of iNOS can be seen as early as 3 hr following the initial injury and lasts up to 24 hr. Early postinjury changes result in maximal expression following stimulation with TNF or IFN-gamma. Later (24 hr post-injury) changes reveal LPS to be the most potent inducer with as little as 0.01 microgram/ml LPS being required for iNOS mRNA expression. The in vivo correlate of tissue injury (turpentine injection) followed by sepsis (intraperitoneal LPS injection) resulted in a three- to fourfold rise in plasma levels of the stable end-products of nitric oxide production, nitrite, and nitrate (NO2- + NO3-), over levels seen in cases of sepsis alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Generation of Large Numbers of Independently Transformed Fertile Barley Plants

A rapid, efficient, and reproducible system to generate large numbers of independently transformed, self-fertile, transgenic barley (Hordeum vulgare L.) plants is described. Immature zygotic embryos, young callus, and microspore-derived embryos were bombarded with a plasmid containing bar and uidA either alone or in combination with another plasmid containing a barley yellow dwarf virus coat protein (BYDVcp) gene. A total of 91 independent bialaphos-resistant callus lines expressed functional phosphinothricin acetyltransferase, the product of bar. Integration of bar was confirmed by DNA hybridization in the 67 lines analyzed. Co-transformation frequencies of 84 and 85% were determined for the two linked genes (bar and uidA) and for two unlinked genes (bar and the BYDVcp gene), respectively. More than 500 green, fertile, transgenic plants were regenerated from 36 transformed callus lines on bialaphos-containing medium; albino plants only were regenerated from 41 lines. T0 plants in 25 lines (three plants per line) were analyzed by DNA hybridization, and all contained bar. Most contained the same integration patterns for the introduced genes (bar, uidA, and the BYDVcp gene) as their parental callus lines. Transmission of the genes to T1 progeny was confirmed in the five families analyzed by DNA hybridization. A germination test of immature T1 embryos on bialaphos-containing medium was useful for selecting individuals that were actively expressing bar, although this was not a good indicator of the presence or absence of bar. Expression of bar in some progeny plants was indicated by resistance to the herbicide Basta. The T1 plants were in soil approximately 7 months after bombardment of the immature embryo.

[Changes of angiotensin II contents in rat plasma, brain, cardiovascular system and adrenal during stress]

The changes of content of angiotensin II (A II) in plasma, anterior hypothalamus, medulla oblongata, myocardium, vasculature and adrenals during acute and chronic stress were studied in rats. Compulsive cold-water swimming and trauma by limb-breaking were used to set acute stress models while cold environment of 4-8 degrees C was used to set chronic stress model. The results showed that: (1) The A II levels in plasma were significantly increased in all three stress- model groups, reaching to 900%, 390% and 134% of the control in the swimming group, the limb-broken group and the cold environment group, respectively. It's clear that the level of angiotension II in the acute stress groups were much higher than those in the chronic stress group. (2) The A II levels of the rat brain, myocardium and blood vessel were also increased in the stress animals except the limb-broken group. Furthermore, the contents of angiotensin II of the chronic stress animals were significantly higher than those of the acute stress animals in the brain, myocardium and blood vessels, but not in the adrenals. (3) The adrenal A II content was significantly higher than that of the control in all stressed animals. (4) The plasma corticosterone was also significantly increased over the control level in both the acute and chronic stress groups. These results suggest that circulating angiotensin II and tissue angiotensin II may play a role during the development of acute and chronic stress, respectively.