Identification and characterization of a novel plant phospholipase D that requires polyphosphoinositides and submicromolar calcium for activity in Arabidopsis

Phospholipase D (PLD; EC 3.1.4.4) has been proposed to be involved in a number of cellular processes including transmembrane signaling and membrane deterioration. PLD previously described from various plant sources generally requires millimolar ranges of calcium for optimal activity. In this study, we genetically suppressed the expression of this conventional PLD in Arabidopsis by introducing an antisense PLD cDNA. However, both the antisense transgenic and wild-type plants showed comparable PLD activity in the presence of submicromolar concentrations of calcium and phosphatidylinositol 4, 5-bisphosphate using phosphatidylcholine as a substrate. This new PLD activity was partially stimulated by phosphatidylinositol 4-phosphate, but not by other phospholipids, including phosphatidylinositol, phosphatidylserine, phosphatidylglycerol, phosphatidic acid, or phosphatidylcholine. Its requirement for polyphosphoinositides was further supported by its ability to be inhibited by neomycin. The polyphosphoinositide-dependent PLD requires calcium for activity, but no magnesium. The calcium stimulation was observed in the nanomolar range and reached a plateau at 5 microM calcium. The findings of this study demonstrate the presence of different PLDs that are regulated in a distinct manner in plants. The potential significance of a PLD that is regulated by polyphosphoinositides and physiological concentrations of Ca2+ is discussed.

[Computer image analysis of 20 tiny medicinal seeds]

Twenty tiny medicinal seeds were determined by computer image analysis. The diameter, perimeter, area, volume and irregular parameter of the seeds are presented.

[Hemorheological disorders in patients with sudden deafness]

Fourteen hemorheological and related parameters of blood samples derived from 59 patients with sudden deafness were observed and were compared with those of blood samples got from 512 healthy persons. The ratio viscosity of whole blood (6.50 +/- 1.07), reduced viscosity of whole blood (12.37 +/- 1.80), and plasma viscosity (1.84 +/- 0.14) in male patients were significantly higher than those (6.05 +/- 0.63, 11.06 +/- 1.04, and 1.70 +/- 0.07, respectively) in male controls. The reduced viscosity of whole blood (16.62 +/- 3.87) and plasma viscosity (1.92 +/- 0.13) in female patients were also significantly higher than those (14.40 +/- 2.27 and 1.72 +/- 0.06, respectively) in female controls. The findings above suggest that there is an intimate relationship between the microcirculationary disorder resulting from hemorheological changes and the onset of sudden deafness. The parameters related to plasma viscosity revealed that there were higher concentrations of plasma fibrinogen and triglyceride in male patients than those in male controls, while the concentrations of plasma cholesterol and triglyceride were higher in female patients than in female controls. These results indicate that the factors which induce the change of plasma viscosity in male patients could not be the same as those in female patients. Thus, in the process of treating sudden deafness, besides the use of common devices such as reducing blood viscosity and improving microcirculation, some other special steps based on the hemorheological parameters derived from different sexes or individuals, should also be considered.

[Mechanism of taxol-induced apoptosis in human breast cancer cells]

OBJECTIVE

To investigate the mechanism by which taxol induces apoptosis in human breast cancer cells.

METHODS

Cell morphology, agarose gel electrophoresis, flow cytometry, video time-lapse monitor and Western blot were performed for taxol-induced apoptosis in human breast cancer cells (Bcap 37).

RESULTS

BCap 37 cells treated with taxol (100 nm) underwent the arrests of cell mitosis at metaphase of mitosis and induction of apoptosis. Apoptotic cells demonstrated cell shringkage, condensation and fragmentation of chromosomes. Nuclear DNA of apoptotic cells displayed ladder bands characteristic of internucleosomal DNA fragmentation. The expression of bcl-2, inhibitor of apoptosis, was decreased with modification, while that of bax, inducer of apoptosis, increased only at early stage of the apoptotic pathway and decreased later.

CONCLUSION

In human breast cancer cells the induction of apoptosis by taxol was closely associated with mitotic arrest of cell cycle, and altered expression of bcl-2 and bax gene, possibly playing an important role in regulating taxol-induced apoptosis.

Studies of a second family with the Quebec platelet disorder: evidence that the degradation of the alpha-granule membrane and its soluble contents are not secondary to a defect in targeting proteins to alpha-granules

We recently described a Quebec family with an autosomal dominant bleeding disorder characterized by mildly reduced-low normal platelet counts, an epinephrine aggregation defect, multimerin deficiency, and proteolytic degradation of several, soluble alpha-granular proteins. Similar clinical features led us to investigate a second family with an unexplained, autosomal dominant bleeding disorder. The affected individuals had reduced to normal platelet counts, absent platelet aggregation with epinephrine, and multimerin deficiency. Their platelet alpha-granular proteins factor V, thrombospondin, von Willebrand factor, fibrinogen, fibronectin, osteonectin, and P-selectin were proteolyzed and comigrated with the degradation products found in patients from the other family. However, their platelet albumin, IgG, external membrane glycoproteins, CD63 (a lysosomal and dense granular protein), calpain, and plasma von Willebrand factor were normal, indicating restriction in the proteins proteolyzed. Electron microscopy studies indicated preserved alpha-granular ultrastructure, despite degradation of soluble and membrane alpha-granular proteins. Immunoelectron microscopy studies of the patients' platelets indicated that fibrinogen, von Willebrand factor, P-selectin, multimerin, and factor V were within alpha-granules, with normal to reduced labeling for these proteins. Pathologic proteolysis of alpha-granular contents, rather than a defect in targeting proteins to alpha-granules, may be the cause of the protein degradation in the Quebec platelet disorder.

Oxygenated intraluminal perfluorocarbon protects intestinal muscosa from ischemia/reperfusion injury

Ischemia/reperfusion (I/R) injury to the intestinal mucosa occurs in several commonly encountered clinical situations, such as necrotizing enterocolitis and nonocclusive mesenteric insufficiency. No clinically feasible technique is available for mucosal preservation during ischemia. The goal of this work was to determine whether the continuous intraluminal flow of oxygenated perfluorocarbon (PFC) could protect mucosal integrity and function in a rat model of intestinal I/R injury. Rats were subjected to ischemia by clipping the superior mesenteric artery (SMA) for 60 minutes. Reperfusion was achieved by release of the clip for 120 minutes. Animals were divided into 4 groups: Sham (laparotomy alone), I/R (I/R alone), I + PFC/R (PFC was administered during the ischemic interval only), I/R + PFC (PFC was delivered only during reperfusion). Tissue sections were examined blindly to assess mucosal integrity, and mucosal dissacharidase activities were measured to assess function. Oxygenated PFC, when administered during ischemia alone, ameliorated I/R-induced mucosal injury; however, when it was delivered during reperfusion alone, the mucosal injury worsened. When oxygenated PFC was administered throughout I/R, the degree of mucosal injury was similar to the I + PFC/R group, and dissacharidase activities were preserved when compared with the I/R group. Intraluminal perfusion of oxygenated PFC during ischemia preserves mucosal function and integrity, and may offer a new treatment modality for a variety of mesenteric ischemic disorders.

Expression of antimetastatic gene nm23-H1 in epithelial ovarian cancer

OBJECTIVE

To investigate the expression of nm23-H1 in epithelial ovarian cancer.

METHODS

A total of 55 specimens from patients with epithelial ovarian cancers, 15 patients with serous cancers, 7 with mucinous cancers, 17 with endometrioid cancers and 16 with adenocarcinomas, were examined for the expression of nm23-H1 by means of the immunohistochemical technique.

RESULTS

The total positive rate was 23.64% (13/55). The tissular nm23-H1 immunostaining had significantly higher expression in mucinous cancer (57.14%) than in other histologic types of epithelial ovarian cancer (P < 0.05). Compared to that in the primary tumor, nm23-H1 expression in the omental metastatic tumor in the same patient was reduced.

CONCLUSIONS

The expression rate of nm23-H1 is higher in the primary tumors than in the metastatic tumors and is different in various histologic subtypes of epithelial ovarian cancer. The expression of nm23-H1 may participate in the inhibitory process of tumor invasion.

[Efficient expression of human C1-inhibitor in CHO cells by using a dicistronic expression vector]

The full-length cDNA fragment encoding human C1-INH was obtained by gene recombination techniques and a stable expression plasmid was constructed by inserting the human C1-INH cDNA into an efficient dicistronic expression vector pED. This plasmid was transfected into DHFR-deficient Chinese Hamster Ovary cells (CHO-dhfr-) by Lipofectin method, and the positive CHO-dhfr+ cell clones which stably express C1-INH was generated. Expression of C1-INH mRNA was detected by Northern blot. Expression of C1-INH protein was confirmed by immunoprecipitation and Western blot analysis. The level of expressed C1-INH was estimated at 0.4 microgram/ml by specific ELISA techniques. The biological activity of recombinant C1-INH was assayed by using the inhibition of C1 estrolytic activity.

The relationship between 67KD laminin receptor expression and metastasis of hepatocellular carcinoma

The 67KD laminin receptor (LN-R) that binds laminin (LN) is involved in the metastasis cascade. Using immunohistochemical technique, in situ hybridization and reverse transcription polymerase chain reaction (RT-PCR), we studied LN-R protein and RNA levels in 30 cases of human hepatocellular carcinoma (HCC) to further understand its role in the metastasis of HCC. In our 14 cases of HCC with metastasis, its positive rates were 71.4%, 57.1%, 85.7% respectively, whereas its positive expression in 16 cases without metastasis were 31.3%, 18.8%, 50.0% respectively. The significant difference was found between these two groups. The results suggest that the 67KD LN-R expression plays a very important role in the metastasis of HCC.

Naturally processed T cell epitopes from human glutamic acid decarboxylase identified using mice transgenic for the type 1 diabetes-associated human MHC class II allele, DRB1*0401

The identification of class II binding peptide epitopes from autoimmune disease-related antigens is an essential step in the development of antigen-specific immune modulation therapy. In the case of type 1 diabetes, T cell and B cell reactivity to the autoantigen glutamic acid decarboxylase 65 (GAD65) is associated with disease development in humans and in nonobese diabetic (NOD) mice. In this study, we identify two DRB1*0401-restricted T cell epitopes from human GAD65, 274-286, and 115-127. Both peptides are immunogenic in transgenic mice expressing functional DRB1*0401 MHC class II molecules but not in nontransgenic littermates. Processing of GAD65 by antigen presenting cells (APC) resulted in the formation of DRB1*0401 complexes loaded with either the 274-286 or 115-127 epitopes, suggesting that these naturally derived epitopes may be displayed on APC recruited into pancreatic islets. The presentation of these two T cell epitopes in the islets of DRB1*0401 individuals who are at risk for type 1 diabetes may allow for antigen-specific recruitment of regulatory cells to the islets following peptide immunization.

Clinical observation on efficacy of electro-acupuncture therapy in hyperplasia of mammary glands and its effect on immunological function

Based on our work on electro-acupuncture therapy of hyperplasia of mammary glands and in order to observe further the relationship between immunological function and E2 in hyperplasia of mammary glands, we determined the change not only in immunological function before and after electro-acupuncture in 44 in-patients with hyperplasia of mammary glands and having the same menstruation date, but also in electro-acupuncture treated rat hyperplasia of mammary glands model. We found that there was decrease of immunological function in hyperplasia of mammary glands and this function could be remarkably enhanced by electro-acupuncture both in hyperplasia of mammary glands patients and in rat hyperplasia of mammary glands model. The mechanism implies it might be that the inhibitory effect on immunological function exerted by high concentration of E2 was lowered by electro-acupuncture, hence the immunological function was reinforced. The results of this study are important in exploration of both the pathogenesis of this disease and the mechanism of electro-acupuncture, and in reducing the incidence of breast carcinoma.

[APC mutation analysis in sporadic colorectal cancer]

APC gene, responsible for familial adenomatous polyposiscoli, is one of the tumor suppressor genes involved in tumorigenesis of sporadic colorectal cancer. Because the majority of APC mutations are located in the 5' end of exon 15 and 95% of them generate stop codon, a coupled in vitro transcription and translation system (IVSP) was used to detect somatic APC mutation of exon 15 in sporadic colorectal cancer. Forty-nine mutated sporadic cases containing 59 truncated bands (9 cases with 2 bands) were identified. The results of the study showed: 1. APC frameshift mutations were more frequent than point mutations (60% vs 40%). Most of the frameshift mutations (32/35) were deletion or insertion of 1-2 bp, whereas 16 of all 23 point mutations presented C-to-T transitions. Mutations (57/59) were mostly but unevenly distributed in segment 2 and 3 of exon 15, while in segment 3, 69% (45/59) of all the mutations were predominantly located in mutation cluster region (codon 1286-1531). In seven of the 9 cases with 2 mutations their close proximity with each other is suggestive of the possibility of mutations at 2 independent alleles. The similarities between APC somatic and germline mutations suggest that APC gene might well have some common functions during the tumorigenesis of sporadic and hereditary coloretal cancer.

[Evaluation of therapeutic effects of moist burn ointment and betadine ointment in treatment of severe burn]

In order to compare the therapeutic value of moist burn ointment (MBO) and betadine ointment in severe burns, the authors divided 30 patients with burn over 30% TBSA into two groups. In one group MBO was used, and in another group betadine was used. The result showed; 1. The difference between two groups was not great in superficial II degree burn wound. 2. MBO was less effective than betadine in deep burn wound. MBO had little antibacterial effect, wound healing was delayed, and incidences of infection, complication and mortality were higher. At the same time, MBO did not have noticeable effect in inhibiting scar hypertrophy. The authors suggest that MBO must be used with caution in severe burn patients, especially in the southern provinces where the climate is hot and humid.

[Treatment of uterine leiomyoma by two different doses of mifepristone]

OBJECTIVE

To study the response of uterine leiomyoma to two different daily dosages of mifepristone.

METHODS

Prospective nonrandomized clinical trial on women with symptomatic uterine leiomyoma was conducted. Twenty-eight patients were treated with 10mg of mifepristone daily and fifteen patients with 20mg daily for 12 weeks, beginning on day 1 to 3 of the menstrual cycle. Volume changes of leiomyoma and uterus were measured with ultrasonography before treatment (as baseline) and monthly during the course of therapy. Blood samples for hemoglobin, liver and renal function were obtained monthly.

RESULTS

Ovarian acyclicity was induced in both groups of patients given different daily doses of mifepristone and dysmenorrhea and low abdominal pain disappeared. All symptoms and signs of anemia were resolved. The average hemoglobin level elevated 14-16g/L monthly. After 12 weeks of mifepristone treatment, the leiomyoma volume decreased to 41.4% of baseline in the 10mg daily dose group and 43.0% in the 20mg daily dose group. There was no significant difference between the two treatment groups; the side effects were similar.

CONCLUSION

Mifepristone of 10mg daily is considered to be a more ideal dosage for treatment. Mifepristone therapy is indicated in larger fibroids, and/or as preoperative medication for severely anemic patients and in perimenopausal patients with symptomatic fibroids.

APC mutations in colorectal tumors with mismatch repair deficiency

We have investigated the influence of genetic instability [replication error (RER) phenotype] on APC (adenomatous polyposis coli), a gene thought to initiate colorectal tumorigenesis. The prevalence of APC mutations was similar in RER and non-RER tumors, indicating that both tumor types share this step in neoplastic transformation. However, in a total of 101 sequenced mutations, we noted a substantial excess of APC frameshift mutations in the RER cases (70% in RER tumors versus 47% in non-RER tumors, P < 0.04). These frameshifts were characteristic of mutations arising in cells deficient in DNA mismatch repair, with a predilection for mononucleotide repeats in the RER tumors (P < 0.0002), particularly (A)n tracts (P < 0.00007). These findings suggest that the genetic instability that is reflected by the RER phenotype precedes, and is responsible for, APC mutation in RER large bowel tumors and have important implications for understanding the very earliest stages of neoplasia in patients with tumors deficient in mismatch repair.

[Differential expression of HSU17714 gene in colorectal cancer and normal colonic mucosa]

HSU17714 is a new gene discovered by subtractive hybridization. Its cDNA is 2,932 bp long and the gene is located at human chromosome 22 as defined by fluorescence in- situ hybridization combined fluorescence R-banding technique. Northern blot and RNA dot blot analyses showed that the expression level of HSU17714 gene was significantly lower in 15 cases of colorectal cancer than that in adjacent normal colonic mucosa. The defective expression of HSU17714 in colorectal cancer suggests that it is a new candidate tumor suppressor gene.

An autosomal dominant, qualitative platelet disorder associated with multimerin deficiency, abnormalities in platelet factor V, thrombospondin, von Willebrand factor, and fibrinogen and an epinephrine aggregation defect

Multimerin is a massive soluble, multimeric protein found in platelets and endothelial cells. Recent studies identified multimerin as a specific coagulation factor V binding protein, complexed with platelet, but not plasma, factor V. These findings led us to investigate individuals with inherited factor V deficiencies for possible multimerin abnormalities. Platelet proteins were evaluated using immunoassays, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunoblotting, immunoprecipitation, and direct binding studies. Patients with factor V Quebec, a disorder with abnormal platelet factor V, had a quantitative deficiency in multimerin (n = 11 tested; mean, 12.5%; range, 5% to 27% of the normal pool; normal range, 45% to 214%) with a normal multimer pattern. Quantitative and qualitative abnormalities were detected in their platelet factor V. An unrelated patient who was deficient in platelet and plasma factor V had normal platelet multimerin. The levels of platelet beta-thromboglobulin, von Willebrand factor, thrombospondin, and fibrinogen antigen were normal in the factor V Quebec patients. However, proteins with abnormal mobility were detected in their platelet lysate and releasate, and their platelet thrombospondin, von Willebrand factor, and fibrinogen showed evidence of proteolytic degradation. Platelet counts of the factor V Quebec patients ranged from mildly thrombocytopenic to low normal (mean, 159 x 10(9)/L; range, 104 to 198 x 10(9)/L). In addition, their platelets failed to aggregate in response to 6 to 10 micromol/L epinephrine despite normal numbers of platelet alpha 2-adrenergic receptors. These data indicate that patients with factor V Quebec have an inherited bleeding disorder distinct from other platelet disorders and associated with multiple abnormalities, including multimerin deficiency, abnormal platelet factor V, thrombospondin, von Willebrand factor, and fibrinogen, and an epinephrine aggregation defect.

A glutamate/glutamine/aspartate/asparagine transport operon in Rhodobacter capsulatus

A mutant of Rhodobacter capsulatus was identified in which an operon encoding a binding-protein-dependent transporter was interrupted by Tn5 transposition. Cloning and sequence analysis of the wild-type operon revealed a four-gene cluster with similarities to genes encoding periplasmic binding proteins (BztA), integral membrane proteins (BztB and BztC), and ATP-binding proteins (BztD). To assess the function of this putative binding-protein-dependent transport system, a mutant was constructed in which most of the bztABCD operon was deleted and replaced by an antibiotic-resistance marker. The deletion mutant grew more slowly than the wild type in NH4(+)-free medium supplemented by glutamate, glutamine, aspartate or asparagine; it was resistant to toxic analogues of Glu, Asp, and Asn at concentrations that inhibited growth of the wild type; and it was defective in the uptake of Glu, Gln, and Asp. A complementing plasmid containing the wildtype copy of bztABCD was able to rescue all the mutant phenotypes. Taken together, these results indicate that the proteins encoded by bztABCD are active in the uptake of Glu, Gln, Asp, and Asn. In addition, competition experiments, in which the ability of each of the four amino acids to compete for the transport of one another was examined, demonstrated that all four substrates share at least one component of this transport system.

[High efficiency eukaryotic expression of rhIL-12 in COS-7 cells]

In this study, two high-efficiency eukaryotic expression vectors, PED35 and PED40 containing p35 and p40 cDNA of rhIL-12 respectively, were co-transfected into COS-7 cells by modified DEAE-Dextran method. The COS-7 cell culture supernatant had been certified to contain high level of expressed rhIL-12 protein, nearly 600 IU/ml. Furthermore, in the two biological assays, the expressed rhIL-12 protein can cause the proliferation of human PHA-activated lymphoblasts and augmentation of NK cells mediated cytotoxic activity. This study, therefore, could help further exploration of biological activities and potential usage of rhIL-12.

[The nonfunctional adrenal tumors: report of 30 cases]

79 cases of adrenal tumors were treated in our hospital from 1985 to Aprit. 1994. 30 of them had nonfunctional adrenal tumors. Data have shown that nonfunction adrenal tumor is not unusual. The detection rate of the disease will increase with the development and popularization of medical imageology which consists of B-ultrasonography and CT scanning etc. In this article, the diagnosis and treatment of this disease were discussed in detail with a review of the literature.

Structural heterogeneity of phospholipase D in 10 dicots

The occurrence of multiple forms of phospholipase D (EC 3.1.4.4) was investigated in different tissues of castor bean (Ricinus communis) and in other plant species. Phospholipase D variants were resolved by nondenaturing and isoelectric focusing polyacrylamide gel electrophoresis and detected by immunoblotting using anti-phospholipase D antibodies and by enzyme activity assay. Three phospholipase D variants were produced differentially in the roots, endosperm, cotyledons, and hypocotyl of 5-day postgermination seedlings of castor bean. Furthermore, different patterns of phospholipase D variants were found in the different regions of hypocotyl (elongated and hook). Multiple phospholipase D forms were found in florets of cauliflower and broccoli, leaves of cabbage, celery, tomato, and potato, and alfalfa sprouts, suggesting that structural heterogeneity of phospholipase D occurs widely in plants.

Increased endothelin expression in a rat cardiac allograft model of chronic vascular rejection

Endothelins (ET) are potent vasoconstrictors that are directly mitogenic for vascular smooth muscle cells and fibroblasts. It is possible that the vasoconstrictor and mitogenic effects of ET could play a significant role in the vascular remodeling process that occurs in chronic vascular rejection (CVR). We have previously shown that cardiac allografts in the indefinitely surviving major histocompatibility complex identical WF.1L (RT1(1)) to Lewis (LEW) (RT1(1)) inbred rat strain combination provide a highly reproducible model of progressive CVR. The objective of this investigation was to measure endothelin-1 ventricular content of WF.1L-LEW cardiac allografts and to determine the immunohistochemical patterns of ET cellular reactivity at well defined posttransplant time periods. Data were compared with those obtained in similar studies of LEW-LEW syngeneic: heart grafts as well as all recipients' own hearts. The ventricular ET-1 content of the WF.1L cardiac allografts was markedly higher (4.3-, 7.0-, and 4.8-fold at 20, 40, and 60 days, respectively) than in corresponding recipients' hearts. Also, the increase in ventricular ET-1 levels as compared with the recipients' hearts rose significantly only in the allograft group. No comparable differences were observed in the syngeneic heart graft controls. Allografts consistently showed ET staining of intimal myocytes at sites of occlusive and subocclusive intimal proliferation associated with CVR. Allografts also showed ET cellular staining in areas of reparative fibrosis associated with indolent interstitial rejection and ischemic myocardial damage. The results of this study strongly suggest that ET may play a significant role in the pathogenesis of CVR.

The induction of ret by Wnt-1 in PC12 cells is atypically dependent on continual Wnt-1 expression

Wild type PC12 pheochromocytoma cells that had been infected with a Wnt-1-carrying virus and thus express Wnt-1 (PC12/Wnt-1) are known to acquire the same flat cell phenotype as that of spontaneously occurring PC12 flat cell variants except that the latter do not presently express Wnt-1. Flat cell variants of PC12 cells exhibit markedly altered morphology and gene expression. In order to assess the possibility that the spontaneously occurring flat cell variants could have been induced in wild type PC12 cells by previous transient expression of the cell's endogenous Wnt-1, we have isolated PC12/Wnt-1 cells expressing little or no Wnt-1. In spite of absent Wnt-1 expression, they retained their flat cell morphology, glutamate/aspartate transporter activity, increased neu mRNA levels and lack of both norepinephrine transporter activity and nerve growth factor-induced differentiation. Thus, Wnt-1 expression is not required to maintain the flat cell phenotype. However, we identified one gene, ret, whose mRNA level in PC12 was not only increased by Wnt-1 expression, but whose increased mRNA level was also dependent on continual Wnt-1 expression. This finding suggests that the induction of ret by Wnt-1 can be used to elucidate the Wnt-induced signalling pathway in mammalian cells.

[Synthesis of substituted benzeneseleninic acid and its antineoplastic activity]

In view of the negative relationship between selenium and cancer, we designed and synthesized eleven substituted benzeneselenic acids (IVa-k) The antineoplastic activity of the title compounds was evaluated via the tests of inhibition of acetylcholinesterase, HL-60 and K562 in vitro, and Ehrlich carcinoma in mice. The result showed that the compounds IVa and IVb had distinct antineoplastic activity. The life span increase rate of IVb on mice bearing Ehrlich carcinoma was 20.30% (20mg/kg), which was higher than the increase rate of sodium selenite (10.65%, 0.5mg/kg).

[Inhibition of colorectal carcinoma induced by 1, 2-dimethylhydrazine in mice with tea polyphenols]

Colorectal cancer was induced by subcutaneous injection of 1,2-dimethylhydrazine (DMH) in mice, and the animals were administered orally with 0.4% of tea polyphenols (TP) simultaneously for 20 weeks to study its preventive effects. Results showed incidence of colorectal cancer in mice administered with TP was significantly lower than in positive controls (P < 0.05), and average number of tumor foci and proportion of adenocarcinoma were significantly fewer in TP group than in positive controls (P < 0.01). Level of cytochrome P450 (CP450) in liver microsome of the mice administered with TP was lower than that both in negative and positive controls (P < 0.01), and activities of superoxide dismutase (SOD) in liver tissue were higher than those in positive controls (P < 0.01), but lower than in negative controls (P < 0.01). Proliferative index of epithelial cells in mice was not obviously influenced by TP. It suggested that TP could have preventive effects on experimental colorectal cancer with a possible mechanism of lowering CP450 and increasing the activity of SOD in the liver.

Does P-glycoprotein play a pivotal role in the drug resistance of an MDR variant, K562/Dox?

A multidrug-resistant (MDR) variant, K562/Dox, was selected from repeated exposure of human erythroleukemia cell line K562 to doxorubicin (Dox). K562/Dox displayed typical MDR features with respect to its cross-resistance to a variety of functionally and structurally unrelated compounds: vincristine (Vin), Dox, mitomycin C, reduced steady-state intracellular anthracycline accumulation, and elevated P-glycoprotein expression/mdr1 mRNA transcription/mdr1 gene amplification. Nevertheless, by incubation of cells with Dox/epirubicin (Epi)/daunorubicin (Dau) (5-80 micrograms/ml), the initial drug uptake was similar (p > 0.05) in K562/Dox and K562 cells, suggesting P-glycoprotein-mediated drug efflux would not occur unless a relatively high cellular drug concentration was reached. After 8 h incubation of cells with 50 ng/ml Dox (5 times higher than its IC50 to K562 cells), there were only slight differences (p > 0.05) in intracellular drug levels between K562/Dox and K562 cells, clearly indicating that K562/Dox, circumventing drug toxicity in this case, was irrelevant to reduced drug accumulation caused by P-glycoprotein. Similar results were obtained when Epi or Dau was applied. Despite complete restoration of anthracycline accumulation in K562/Dox cells in the presence of 6 mumol/l verapamil, the reversal of their drug resistance was incomplete. These results suggest that P-glycoprotein-mediated drug efflux possibly did not play a primary role in the drug resistance of K562/Dox cells.

5' termini of Pichinde arenavirus S RNAs and mRNAs contain nontemplated nucleotides

Primer extension of Pichinde arenavirus purified virion RNA suggests that genomes have at least a single nontemplated base at the 5' end which is a G in all cDNA clones having one such single base. On the other hand, the predominant products of primer extension on total virus-infected-cell RNA are at positions -1 and -2. The primer extension product at position -2 is not represented in virion RNA, and neither of these products is proportionally represented in mRNA. mRNA is predominantly 3 or 4 bases longer than genomes and antigenomes, but primer extension products as long as 7 bases were observed. The sequence of nontemplated bases reported here is unambiguous with respect to the 5'-terminal base and supports the view that there is a sequence preference for a G at the 5' termini of mRNAs. Assessment of our sequence data in the context of the sequences of Tacaribe and lymphocytic choriomeningitis viruses suggests that the mechanism of initiation of arenavirus transcription is fundamentally different from that of members of the families Orthomyxoviridae and Bunyaviridae.

Expression cloning of a protective Leishmania antigen

Parasite-specific CD4+ T cells have been shown to transfer protection against Leishmania major in susceptible BALB/c mice. An epitope-tagged expression library was used to identify the antigen recognized by a protective CD4+ T cell clone. The expression library allowed recombinant proteins made in bacteria to be captured by macrophages for presentation to T cells restricted to major histocompatibility complex class II. A conserved 36-kilodalton member of the tryptophan-aspartic acid repeat family of proteins was identified that was expressed in both stages of the parasite life cycle. A 24-kilodalton portion of this antigen protected susceptible mice when administered as a vaccine with interleukin-12 before infection.

Analysis of Pichinde arenavirus transcription and replication in human THP-1 monocytic cells

Human promonocytic THP-1 cells were previously shown to be nonpermissive for Pichinde virus (PV) replication unless the cells were induced to differentiate to macrophages by stimulation with phorbol ester (PMA) (J. Virol. 65, 3575, 1991). The restriction did not involve receptor modulation, virus binding, nor internalization of virus but a requirement for a host cell function in PV replication was observed in that the phorbol ester effect required protein kinase C activation and was inhibited by actinomycin D. In this report we demonstrate that PV S RNA genomes, antigenomes, GPC mRNA and NP mRNA are expressed at high levels in PMA treated THP-1 cells but at significantly lower levels or not at all in untreated cells. We have also determined that degradation of input viral S RNA does not account for decreased PV RNA synthesis in the undifferentiated cells. This suggests that the restriction of PV replication in THP-1 cells is a post-penetration event which precedes transcription of viral mRNAs and replication of viral genomes and supports a role for differentiation-specific host cell factors early in PV replication.

[Reduced intracellular drug accumulation related to overexpression of P-glycoprotein cannot explain the complete drug resistance in MDR cell variant K562/Dox]

The purpose of this study was to determine what proportion of drug resistance of MDR cell variant K562/Dox was attributed to the reduced steady state intracellular drug accumulation related to overexpression of P-glycoprotein. K562/Dox was derived from repeated exposure of human erythroleukaemic cell line K562 cell to doxorubicin. As assessed with MTT assay, the resistance of K562/Dox to 7 cytotoxic drugs increased variably in the range between 1200 and 11 folds. K562/Dox cells were positively stained with anti-human p-glycoprotein monoclonal antibody JSB-1, indicating overexpression of P-gp. Intracellular drug accumulation in K562/Dox, though significantly reduced as compared with that in K562 cells, was maximally restored by concurrent exposure of cells to 6 mumol/L verapamil and 1.72 mumol/L either of the doxorubicin, epirubicin or daunorubicin. Similar results were obtained by exposure of cells to 12 mumol/L verapamil and 8.62 mumol/L drug, indicating that restoration of intracellular drug accumulation in MDR cells was dependent on the relative concentrations of verapamil to drug. However, the resistances of K562/Dox cells to epirubicin and daunorubicin still remained for about 5.6 and > 6.6 folds, respectively, even at verapamil concentration of 6 mumol/L, suggesting at least a relatively big fraction of drug resistance was not directly related to the altered cellular pharmacokinetics associated with overexpression of P-glycoprotein.

Influence of steric stabilization of liposome-encapsulated hemoglobin on Listeria monocytogenes host defense

Liposome-encapsulated hemoglobin (LEH) products are being investigated as potential blood substitutes. To determine if changes in LEH composition can modify the immune response, red blood cell substitutes based on conventional lipids containing phosphatidylinositol (LEH1) and sterically stabilized lipid vesicles containing polyethylene glycol phosphatidylethanolamine (LEH2) were tested for effects on host resistance. On Day 0, groups of 18 to 20 female CD-1 mice were given an intravenous (i.v.) infectious challenge with a 20% lethal dose of Listeria monocytogenes. Mice received a single i.v. dose of LEH1, LEH2, or albumin vehicle on Day +1 or Day -3 relative to infectious challenge. Mice dosed with LEH1 and LEH2 on Day +1 died rapidly from Listeria infection; but mice dosed with LEH2 lived significantly longer than did mice receiving LEH1. By contrast, when administered on Day -3, LEH1 had no significant effect on host immunity, while LEH2 increased susceptibility to Listeria infection. In addition, LEH1 and LEH2 both caused significant reduction of phagocytic activity as measured by rat alveolar macrophage (AM) ingestion of latex microspheres. AM incubated 4 hr with either LEH1 or LEH2 prior to addition of microspheres ingested fewer beads in a dose-dependent manner. No difference in in vitro phagocytic activity was observed between LEH1 or LEH2. The inability to differentiate LEH formulations based on in vitro phagocytic activity suggests that the in vivo Listeria infection model may be more relevant in discerning the immunotoxicity of the LEH formulations tested.

Mutational analysis of patients with X-linked adrenoleukodystrophy

Adrenoleukodystrophy (ALD) is an X-linked neurodegenerative disorder characterized by elevated very long chain fatty acid (VLCFA) levels, reduced activity of peroxisomal VLCFA-CoA ligase, and variable phenotypic expression. A putative gene for ALD was recently identified and surprisingly encodes a protein (ALDP) that belongs to a family of transmembrane transporters regulated or activated by ATP (the ABC proteins). We have examined genomic DNA from ALD probands for mutations in the putative ALD gene. We detected large deletions of the carboxyl-terminal portion of the gene in 4 of 112 probands. Twenty-five of the ALD probands whose ALD genes appeared normal by Southern blot analysis were surveyed for mutations by Single Strand Conformation Polymorphism (SSCP) procedures and DNA sequence analysis. SSCP variants were detected in 22 probands and none in 60 X-chromosomes from normal individuals. Mutations were detected in all of the ALD probands. The mutations were distributed throughout the gene and did not correlate with phenotype. Approximately half were non-recurrent missense mutations of which 64% occurred in CpG dinucleotides. There was a cluster of frameshift mutations in a small region of exon 5, including an identical AG deletion in 7 unrelated probands. These data strongly support the supposition that mutations in the putative ALD gene result in ALD.

[Clinical significance of urodynamic study in benign prostatic hyperplasia]

Urodynamic study, including UFR, cystometry, UPP, and EMG was carried out in 74 patients with benign prostatic hyperplasia (BPH) during the past 5 years. The correlations of prostate volume (57.3 +/- 6.3 ml), prostate length (4.94 +/- 1.23 cm) and detrusor pressure (6.54 +/- 4.73 kPa) were analysed. The results showed that urodynamic study plays an important role in indicating the time and method of operative treatment and predicting the prognosis of BPH operation. The fistularization of the bladder should be performed on the patients with the bladder disfunction. The measurement of the urethral resistance is of value in the diagnosis of posterior urethra obstruction than that of UFR.

Microencapsulation of hemoglobin in liposomes using a double emulsion, film dehydration/rehydration approach

A double emulsion, film dehydration/rehydration approach was developed for encapsulation of hemoglobin (Hb) at high concentration in liposomes. The liposome-encapsulated Hb (LEH) membrane was formulated to contain either phosphatidylinositol (PI) or polyethyleneglycol phosphatidylethanolamine (PEG-PE) along with partially hydrogenated egg-PC, cholesterol, and alpha-tocopherol in a molar ratio of 0.1:1:1:0.02, respectively. The methods introduced in this study followed a multi-step procedure. First, a primary emulsion of Hb in organic solvent containing dissolved lipids was formed. Next, the emulsion was dispersed into an aqueous continuous phase to form a water-in-oil-in-water type double emulsion. Other than the lipids noted above, no surfactants were used in this system. The double emulsion was then converted to LEH by the following steps: evaporating the organic solvent; dehydrating the water to form a dry, thin Hb-lipid film; rehydrating the film in Hb solution to form the LEH; reducing the size of the LEH using 'microfluidization' i.e., high pressure/hydrodynamic shear; and lastly washing the down-sized LEH in buffer. Physico-chemical properties of the model LEH were measured, including oxygen content, encapsulated Hb concentration, oxygen affinity and cooperativity, vesicular size distribution, viscosity, and stability. The suitability of LEH prepared in this manner as a red blood cell substitute was shown using continuous isovolemic exchange transfusion techniques in a small animal model: clearance, efficacy and acute toxicity were evaluated.

Interferon gamma-independent effects of interleukin 12 administered during acute or established infection due to Leishmania major

Interleukin 12 (IL-12) is a powerful stimulus for the growth of activated T and natural killer cells, their generation of interferon gamma (IFN-gamma), and the differentiation of T helper type 1 (Th1) effector cells from naive precursors in vitro. These activities are consistent with the capacity of exogenous IL-12 to heal otherwise susceptible BALB/c mice infected with the intramacrophage parasite Leishmania major. Using this characterized model of CD4 cell subset differentiation, we examined the immunologic effects of IL-12 administered either at the time of infection, when naive T cells are primed, or after 14 days of infection, by which time CD4+ subset differentiation has occurred. Given with the inoculation of parasites, IL-12 induced IFN-gamma and IL-10 and markedly suppressed IL-4. Effects on IL-10 and IL-4 were comparable in mice with homozygous disruption of the IFN-gamma gene (IFN-gamma 0/0), and suppression of IL-4 was unchanged by administration of neutralizing anti-IL-10 antibody. Induction of IFN-gamma and IL-10 mRNA by IL-12 also occurred in infected SCID mice. Given after day 14 of infection, however, IL-12 not only induced IFN-gamma and IL-10 but also induced IL-4 in normal and IFN-gamma 0/0 mice. These data demonstrate direct effects of IL-12 independent of IFN-gamma, IL-10, and IL-4 and demonstrate that the ineffectiveness of IL-12 administered following infection with L. major correlates with resistance of differentiated Th2 cells to the IL-4-suppressing activity of IL-12.

[A study of occupational asthma and specific IgE in sericulture workers]

Clinical investigation revealed that 75.6% (68/90) of sericulture workers examined had allergic respiratory symptoms. Of the 90 workers, 14 (15.6%) suffered from occupational asthma. Work-related allergens including silkworm cocoon (SC), silkworm urine (SU), moth excrete (ME) and moth scales (MS) were collected and prepared. Serum specific IgE levels were detected by ELISA. The results showed that the level of sIgE in asthmatic workers was significantly higher than that in the "common symptom" group, asymptomatic group and control group. No significant difference in total IgE was found between the workers and controls. The anti-SU-sIgE positive rate was significantly higher than those of sIgE to the other three allergens. These results indicate that the high levels of sIgE are responsible for occupational asthma in sericulture workers and that SU is an important allergen in these patients.

Cyclosporine and the reversibility of chronic vascular rejection

A model of chronic vascular rejection of cardiac allografts has been developed in inbred rats using the WF.1L/Gut congenic strain as donor into LEW recipients. The hearts beat for more than 200 days without the need for exogenous immunosuppression. The histopathology is characterized by cellular rejection, vasculitis, and myointimal arterial wall thickening, and by day 60 posttransplant, there are widespread occlusive vascular changes similar to those seen in human cardiac allografts. CsA, at a dose of 15 mg/kg/d, is effective in preventing as well as reversing the vasculopathy. These data (1) confirm other studies of ours on the reliability of the experimental model using this strain combination, (2) establish the time window of days 40 to 60 whereby mechanisms of lesion regression can be studied, (3) prove the MHC class I and class II antigen incompatibility are not a necessary condition for the generation of the vascular lesions, (4) show that CsA is a useful probe for study of the vasculopathy, and (5) suggest that the model is a useful probe of the mechanism of action of CsA.

Comparison of dietary habits, physical activity and body size among Chinese in North America and China

BACKGROUND

Chinese in North America have higher rates of many chronic diseases than do Chinese in Asia. However, there is a lack of data among comparisons of the environmental and lifestyle factors for Chinese in China and Chinese residing in North America.

METHODS

We examined self-reported dietary nutrient intakes, physical activity patterns and body mass index of 2488 healthy Chinese men and women residing in North America (US and Canada) and in the People's Republic of China.

RESULTS

On average, Chinese in China consumed more calories (males 2904 kcal in China, versus 2201 kcal in North America; females 2317 Kcal in China, versus 1795 Kcal in North America and more carbohydrate, but less fat (males 72.2 g in China versus 84.5 g in North America, females 56.6 g in China versus 70.8 g in North America), protein, vitamin A, beta-carotene and vitamin C than did Chinese in North America. Per cent calories from fat was 35% for Chinese in North America and 22% for Chinese in China. In contrast, the per cent of calories from carbohydrates was 62-68% in China and 48% in North America. Chinese in China reported spending more time in vigorous activity, sleeping and walking but less hours in sitting than Chinese in North America. Chinese in China weighted less and were leaner than North American Chinese.

CONCLUSIONS

These differences in nutrient intakes, physical activity and body size of Chinese living on two different continents suggest possible explanations for observed differences in chronic disease rates in the two populations.

[Detection of a gene mutation in familial adenomatous polyposis families by PCR-RFLP method]

A simple and rapid PCR-RFLP method was used to detect a mutation hotspot of adenomatous polyposis coli (APC) gene. Among seven familial adenomatous polyposis (FAP) families, we found individuals in family FD carrying a mutated APC gene or a mutated APC allele with AAAGA deletion in codon 1,309 region. Two young affected persons in twenties were detected by screening the family FD kindred with this PCR-RFLP method. The results are in good accordance with those of colonoscopic examination. The PCR-RFLP method we established proves to be a reliable and simple technique for early detection of some FAP patients. The results indicated the existence of same kind of APC gene mutations in Chinese FAP families as those in western countries.

CD4+ effector cells default to the Th2 pathway in interferon gamma-deficient mice infected with Leishmania major

Mice with homologous disruption of the interferon gamma (IFN-gamma) gene on the C57BL/6 background were infected with Leishmania major and the immune response assessed. In contrast to wild-type or heterozygous knockout mice, deficient animals were unable to restrict growth of the parasite and suffered lethal infection over 6-8 wk. Although wild-type and heterozygous littermates developed CD4+ cells that contained transcripts for IFN-gamma and lymphotoxin, typical of T helper type 1 (Th1) cells, the knockout mice developed CD4+ cells that contained transcripts for interleukin 4 (IL-4), IL-5, and IL-13, typical of Th2 cells. ELISPOT assays confirmed the reciprocal patterns of IFN-gamma or IL-4 production by T cells in similar frequencies in the respective groups of mice, and antibody analysis confirmed the presence of Th2-mediated isotype switching in the knockout mice. These data suggest that CD4+ T cells that normally respond to antigens by differentiation to Th1 cells default to the Th2 pathway in the absence of endogenous IFN-gamma.

[Photodynamic effect of chlorophyll derivative (CPD4) with pulsed copper-vapor laser on mouse transplanted tumor]

An experimental study on photodynamic effect of newly developed photosensitizer CPD4 with pulsed copper-vapor laser and pumped dye laser to mouse transplanted tumor (CT26) was carried out. The results showed that: (1) Ten days after treatment by CPD4 with 630nm laser, the mean tumor volume of control group (n = 9) was 1.0 +/- 0.68cm3, while that of treatment group (n = 18) was 0.45 +/- 0.5cm3 (P < 0.01), with an inhibitory rate of 55%. In the treatment group, 8 mice that were treated with a dose > or = 50mg/kg(iv) of CPD4, 280mW/cm2 of laser power density and 10 minutes of irradiation, were all cured with survival time over 6 months, while that of mice in the control group was 28.2 days (2) Under certain condition (light energy 120 J/cm2), with CPD4 as a sensitizer, the mean depths of tumor necrosis were 4.9 +/- 1.0mm (n = 5), 2.8 +/- 1.1mm(n = 11), 1.8 +/- 0.5mm(n = 9) for wavelength of 670nm, 630nm and 510nm, respectively (P < 0.01). When a conventional photosensitizer hematoporphyrin derivative was used, the depths of tumor necrosis were 0 (n = 6) 2.3 +/- 0.3 (n = 5) and 2.8 +/- 1.2 (n = 5)mm for 670, 630 and 510nm, respectively. Based on the above mentioned results, a rational treatment condition in clinical application of CPD4 with copper-vapor laser and pumped dye laser was suggested.

Characterization of anti-canine cytokine monoclonal antibodies specific for IFN-gamma: effect of anti-IFN-gamma on renal transplant rejection

Two murine monoclonal antibodies specific for IFN-gamma, ADI-1, and ADI-23 (both IgG1 kappa), were generated in BALB/c mice. The ADI-1 exhibited a higher avidity for canine rIFN-gamma than for nIFN-gamma and human rIFN-gamma. In contrast, the ADI-23 showed equal avidity for the three IFN-gamma preparations. The anti-canine IFN-gamma mAb did not bind to mouse and rat rIFN-gamma. The ADI-1, and ADI-23 mAb were also tested for binding to human rTFN-alpha and, contrary to our expectations, it was found that ADI-23 showed significant binding to human rTFN-alpha and rIFN-gamma, in contrast to ADI-1. Both anti-canine IFN-gamma mAb stained 48-h PHA-induced dog lymphoblasts. A two-site mAb ELISA was developed, which was linear in the range of 7-500 ng of canine rIFN-gamma, which indicated that the two mAb detected non-overlapping epitopes on the canine rIFN-gamma molecule. We studied the effect of ADI-1 on the prolongation of canine renal allografts. Recipients of kidney allografts, that were treated with ADI-1 by continuous arterial infusion, were prolonged to 22 and 25 days, compared to 9 and 13 days for animals given the IgG1 isotype control.

Leishmania promastigotes evade interleukin 12 (IL-12) induction by macrophages and stimulate a broad range of cytokines from CD4+ T cells during initiation of infection

Leishmania major are intramacrophage parasites whose eradication requires the induction of T helper 1 (Th1) effector cells capable of activating macrophages to a microbicidal state. Interleukin 12 (IL-12) has been recently identified as a macrophage-derived cytokine capable of mediating Th1 effector cell development, and of markedly enhancing interferon gamma (IFN-gamma) production by T cells and natural killer cells. Infection of macrophages in vitro by promastigotes of L. major caused no induction of IL-12 p40 transcripts, whereas stimulation using heat-killed Listeria or bacterial lipopolysaccharide induced readily detectable IL-12 mRNA. Using a competitor construct to quantitate a number of transcripts, a kinetic analysis of cytokine induction during the first few days of infection by L. major was performed. All strains of mice examined, including susceptible BALB/c and resistant C57BL/6, B10.D2, and C3H/HeN, had the appearance of a CD4+ population in the draining lymph nodes that contained transcripts for IL-2, IL-4, and IFN-gamma (and in some cases, IL-10) that peaked 4 d after infection. In resistant mice, the transcripts for IL-2, IL-4, and IL-10 were subsequently downregulated, whereas in susceptible BALB/c mice, these transcripts were only slightly decreased, and IL-4 continued to be reexpressed at high levels. IL-12 transcripts were first detected in vivo by 7 d after infection, consistent with induction by intracellular amastigotes. Challenge of macrophages in vitro confirmed that amastigotes, in contrast to promastigotes, induced IL-12 p40 mRNA. Reexamination of the cytokine mRNA at 4 d revealed expression of IL-13 in all strains analyzed, suggesting that IL-2 and IL-13 may mediate the IL-12-independent production of IFN-gamma during the first days after infection. Leishmania have evolved to avoid inducing IL-12 from host macrophages during transmission from the insect vector, and cause a striking induction of mRNAs for IL-2, IL-4, IL-10, and IL-13 in CD4+ T cells. Each of these activities may favor survival of the organism.