Distributions of iron, manganese, copper and zinc in various composts and amended soils

A detailed observation was conducted on Fe, Mn, Cu and Zn in the composts derived from seafood processing by-product, garbage, swine manure and sewage sludge, respectively, as well as in amended farmlands. All elements were at lower levels of total contents but a higher percentage of water-soluble and exchangeable forms in composted seafood processing by-product and composted garbage than in composted swine manure and composted sewage sludge. Total contents increased in the order: composted seafood processing by-product approximately composted garbage < composted swine manure < composted sewage sludge. The applications of composted seafood processing by-product and composted garbage have neither caused Fe, Mn, Cu and Zn accumulation nor changed their distribution in soils; while the application of composted swine manure has largely increased Cu and Zn contents in soils, mainly in organic matter-bound form, and that of composted sewage sludge increased Mn, Cu and Zn in soils mainly in carbonate-bond and Fe-Mn oxides-bound ones. Fe is an exception, its total contents in soils decreased with the applications of composts except for composted garbage. Also, the rainfall and irrigation were another two main factors that affected available elements in soils.

Alterations in g-protein-linked signal transduction in vascular smooth muscle in diabetes

The present studies were undertaken to determine the levels of stimulatory and inhibitory guanine nucleotide regulatory proteins (Gs and Gi respectively) and their relationship with adenylyl cyclase activity in aorta from 5-day streptozotocin-induced diabetic (STZ) rats. The levels of Gi alpha-2 as determined by immunoblotting techniques using AS/7 antibody were significantly decreased by about 60% in STZ as compared to control rats, whereas the levels of Gs alpha were not altered. In addition, the stimulatory effect of cholera toxin (CT) on GTP-sensitive adenylyl cyclase was not different in STZ as compared to control rats. On the other hand, the stimulatory effects of GTPgammaS, isoproterenol, glucagon, forskolin (FSK) and sodium fluoride on adenylyl cyclase were enhanced in STZ-rats. Furthermore, GTPgammaS inhibited FSK-stimulated adenylyl cyclase activity in a concentration-dependent manner (receptor independent functions of Gi) in control rats which was almost completely abolished in STZ rats. In addition, receptor-mediated inhibition of adenylyl cyclase by angiotensin II (AII), oxotremorine and atrial natriuretic peptide (ANP) was attenuated in STZ rats. These results suggest that the decreased expression of Gi alpha, but not of Gs alpha, may be responsible for the observed altered responsiveness of adenylyl cyclase to hormonal stimulation and inhibition in STZ-rats. It may thus be suggested that the decreased Gi activity may be one of the possible mechanisms responsible for the impaired vascular functions in diabetes.

[Computer-assisted acquisition and analysis of high-resolution spectrum]

Based on the unique characteristic of spectral line center in the whole spectrum and noise threshold, a computer approach and program for the determination of spectral line position and relative intensity automatically are presented in this paper. Exploring this approach and computer program, we pre-analyzed the partially overlapped 16 line TuFIR experiment spectra of CHF3. The results of line positions and intensities for these TuFIR spectra are in excellent agreement with the results by least-square fit with heavily manual inference. The accuracy and efficiency of this method and program will ensure their wide application in complex high-resolution molecular spectrum.

Isolation of an esterase-producing Trichosporon brassicae and its catalytic performance in kinetic resolution of ketoprofen

A yeast strain CGMCC 0574, identified as Trichosporon brassicae, was selected from 92 strains for its high (S) selectivity in the hydrolysis of ketoprofen ethyl ester. The effective strains of the microorganisms were isolated from soil samples with the ester as the sole carbon source. The ethyl ester proved to be the best substrate for resolution of ketoprofen among several ketoprofen esters examined. The resting cells of CGMCC 0574 could catalyze the hydrolysis of ketoprofen ethyl ester with an enantiomeric ratio of 44.9, giving (S)-ketoprofen an enantiomeric excess of 91.5% at 42% conversion.

Improved binding of a bivalent single-chain immunotoxin results in increased efficacy for in vivo T-cell depletion

Anti-CD3 immunotoxins exhibit considerable promise for the induction of transplantation tolerance in pre-clinical large animal models. Recently an anti-human anti-CD3epsilon single-chain immunotoxin based on truncated diphtheria toxin has been described that can be expressed in CHO cells that have been mutated to diphtheria toxin resistance. After the two toxin glycosylation sites were removed, the bioactivity of the expressed immunotoxin was nearly equal to that of the chemically conjugated immunotoxin. This immunotoxin, A-dmDT390-sFv, contains diphtheria toxin to residue 390 at the N-terminus followed by VL and VH domains of antibody UCHT1 linked by a (G(4)S)(3) spacer (sFv). Surprisingly, we now report that this immunotoxin is severely compromised in its binding affinity toward CD3(+) cells as compared with the intact parental UCHT1 antibody, the UCHT1 Fab fragment or the engineered UCHT1 sFv domain alone. Binding was increased 7-fold by adding an additional identical sFv domain to the immunotoxin generating a divalent construct, A-dmDT390-bisFv (G(4)S). In vitro potency increased 10-fold over the chemically conjugated immunotoxin, UCHT1-CRM9 and the monovalent A-dmDT390-sFv. The in vivo potency of the genetically engineered immunotoxins was assayed in the transgenic heterozygote mouse, tgepsilon 600, in which the T-cells express human CD3epsilon as well as murine CD3epsilon. T-cell depletion in the spleen and lymph node observed with the divalent construct was increased 9- and 34-fold, respectively, compared with the monovalent construct. The additional sFv domain appears partially to compensate for steric hindrance of immunotoxin binding due to the large N-terminal toxin domain.

Quantitative evaluation of synaptophysin-like immunoreactive nerve terminals or varicosities in anterior pituitary of normal and adrenalectomized rats

Our previous studies have demonstrated the presence of substantial amounts of peptidergic nerve fibres in the anterior pituitary of monkeys, dogs and rats. The nerve fibres increase in number following adrenalectomy and ovariectomy. Furthermore, typical synapses between nerve fibres and anterior pituitary glandular cells have been demonstrated in the dog and rat, strongly suggesting the existence of some direct neural regulation. However, it is difficult to evaluate the functional importance of synapses or nerve terminals in general, unless quantitative data can be provided. The present study therefore aimed to quantify the number of terminals or varicosities in the anterior pituitary of the rat and its changes following adrenalectomy. Nerve terminals or varicosities were identified by their synaptophysin (SYN)-like immunoreactivity. Under the light microscope, SYN-like immunoreactivity appeared mainly as dots, mostly among glandular cells, and some were found distributed along blood vessels. SYN-like immunoreactive dots were found under the electron microscope to be localized in the nerve terminals or varicosities. Synapse-like contracts between the nerve terminals or varicosities and the glandular cells could be identified. The number of SYN-like immunoreactive nerve terminals or varicosities was then counted under the light microscope. There were as many as 12424.2 +/- 2941.5 and 20700.4 +/- 6128 (mean +/- SD) nerve terminals or varicosities per anterior pituitary of normal and adrenalectomized rats, respectively. The increase in number following adrenalectomy was statistically significant. It is concluded that nerve fibres may play an important role in the regulation of the anterior pituitary.

Increase in cytochrome oxidase activity in regenerating nerve fibers of hemitransected spinal cord in the rat

We explored the possibility of cytochrome oxidase (CO) involvement in spinal cord regeneration in adult rats. The spinal cord was hemitransected at T9. After one month's survival, the animals were deeply anesthetized and perfused. The spinal cord segments including the lesion site were removed and sectioned horizontally for CO histochemistry. Under light microscope, a substantial number of CO-reactive nerve fibers and boutons were identified in the lateral funiculus adjacent to the lesion site. Under electron microscope, moderately to highly CO-reactive mitochondria could be seen within nerve fibers and boutons. Synaptic contacts were identified among them. The increase in CO activity in nerve fibers and boutons may indicate their high-energy demand for synaptic and spontaneous activity following spinal cord hemisection.

Distribution and colocalization of neurotransmitters and receptors in the pre-Bötzinger complex of rats

The pre-Bötzinger complex (PBC), thought to be the center of respiratory rhythm generation, is a cell column ventrolateral to the nucleus ambiguus. The present study analyzed its cellular and neurochemical composition in adult rats. PBC neurons were mainly oval, fusiform, or multipolar in shape and small to medium in size. Neurokinin-1 receptor, a marker of the PBC, was present in the plasma membrane of mostly medium and small neurons and their associated processes and boutons. Among neurons immunoreactive for different neurotransmitter or receptor candidates, various numbers were colocalized with neurokinin-1 receptor. The highest ratio was with nitric oxide synthase (52.72%), and the lowest was with glycine receptors (31.93%). Glutamic acid decarboxylase- and glycine transporter 2-immunoreactive boutons, as well as GABA(A) receptor-immunoreactive plasma membrane processes and boutons, were also identified in the PBC. PBC neurons exhibited different levels of cytochrome oxidase activity, indicating their various energy demands. Our results suggest that synaptic interactions within the PBC of adult rats involve a variety of neurotransmitter and receptor types and that nitric oxide may play an important role in addition to glutamate, GABA, glycine, and neurokinin.

[Effects of several different irritation factors on leukocytes adhesion in microvessels]

AIM

The interrelation of adhesion between leukocyte and endothelium was studied by several irritation factors.

METHODS

Leukocyte adhesion was observed by impulse electricity irritation, ischemia/reperfusion, endotoxin and IL-8 in venular of rat mesentery.

RESULTS

The results showed these irritation factors resulted in a significant increase in the number of leukocytes adhesion along the venular endothelium of rat mesentery. IL-8 leaded to the most increase of leukocytes adhesion. Especially treated by IL-8 for 30 minutes. The number of leukocytes adhesion of the others was approximately identical.

CONCLUSION

The study suggests that impulse electricity irritation, ischemia/reperfusion, endotoxin and IL-8 are able to induce leukocytes and endothelium adhesion, and IL-8 of them has the most effect.

Simultaneous determination of clozapine, norclozapine and clozapine-N-oxide in human plasma by high-performance liquid chromatography with ultraviolet detection

A reversed-phase high-performance liquid chromatographic (HPLC) method for the simultaneous determination of clozapine and its two major metabolites, norclozapine and clozapine-N-oxide in human plasma has been developed and validated. The isocratic HPLC assay uses a mobile phase consisting of an acetonitril-buffered aqueous solution containing 146 microL of triethylamine and 200 microL of 85% phosphoric acid, adjusted to pH 3.3 with 10% potassiumhydroxide solution (400:600, v/v) at a flow-rate of 0.8 ml/min and a Lichrospher 100 RP-18 reversed-phase column and UV detection at 215 nm. Doxepine was used as the internal standard. Mean recoveries for clozapine, norclozapine, clozapine-N-oxide and doxepine were 95%, 98%, 96% and 94%, respectively, whereas the respective mean repeatability coefficients of variation were 3.4%, 2.7%, 4.3% and 0.9%. Reproducibility coefficients of variation were 1.3%, 1.8%, 3.6% and 0.5%, respectively. The mean correlation coefficient for the linear calibration curve (n = 2) for clozapine and norclozapine at a concentration range of 100-1600 ng/mL was 0.9998 and 0.9997, respectively; for clozapine-N-oxide (20-200 ng/mL) it was found to be 0.9986. The lower limits of quantitation were 12.5 ng/mL, 10 ng/mL and 12.5 ng/mL for clozapine, norclozapine and clozapine-N-oxide, respectively.

Taxol-induced ceramide generation and apoptosis in human breast cancer cells

PURPOSE

Taxol has emerged as a valuable antimitotic chemotherapeutic agent, particularly in advanced breast and ovarian cancers. Although much is known about cytotoxic mechanisms, the effectiveness of Taxol cannot be solely explained by microtubular interaction. This study was undertaken to determine whether ceramide generation plays a role in Taxol-induced apoptosis.

METHODS

Hormone-independent MDA-MB-468 and hormone-dependent MCF-7 breast cancer cell lines were employed, and ceramide metabolism was characterized using [3H]palmitic acid as lipid precursor.

RESULTS

Exposure of cells to Taxol resulted in enhanced formation of [3H]ceramide. Ceramide increased nearly 2-fold in MDA-MB-468 cells exposed to 50 nM Taxol, and more than 2.5-fold in MCF-7 cells exposed to 1.0 microM Taxol. These concentrations mirrored the EC50 (amount of drug eliciting 50% cell kill) for Taxol in the two cell lines. Use of cell-permeable C6-ceramide as a medium supplement revealed that MDA-MB-468 cells were 20-fold more sensitive to ceramide than MCF-7 cells (P < 0.001). Ceramide was generated as early as 6 h after exposure to Taxol in MDA-MB-468 cells, whereas the earliest signs of apoptosis were detected 12 h after treatment, and by 24 h the apoptotic index was six times that of untreated cells. Both fumonisin B1, a ceramide synthase inhibitor, and L-cycloserine, a serine palmitoyltransferase inhibitor, blocked Taxol-induced ceramide generation, whilst sphingomyelin levels remained unchanged, indicating a de novo pathway of ceramide formation. L-Cycloserine reduced Taxol-induced apoptosis by 30% in MDA-MB-468 cells and totally blocked Taxol-induced apoptosis in MCF-7 cells.

CONCLUSIONS

These results suggest that Taxol-induced apoptosis is, in part, attributable to ceramide and sphingoid bases. This is of relevance to drug mechanism studies, as ceramide is a known messenger of apoptosis. Clinical use of Taxol with ceramide-enhancing agents may maximize cytotoxic potential.

Differential regulation of heterodimerization by 1alpha,25-dihydroxyvitamin D(3) and its 20-epi analog

Twenty-epi analogs of 1alpha,25-dihydroxyvitamin D(3) (1alpha,25(OH)(2)D(3)) are 100-1000 times more potent transcriptionally than the natural hormone. To determine to what extent this enhanced activity is mediated through modulation of the dimerization process, we performed quantitative dimerization assays with in vitro translated vitamin D receptor (ivtVDR) and fusion proteins containing glutathione-S-transferase (GST) and either the ligand-binding domain of VDR (GST-VDR) or retinoid X receptor (RXR)alpha (GST-RXR). We found that VDR did not form homodimers in either the presence or absence of ligand, but heterodimerization of the ligand-binding domains of RXRalpha and VDR was primarily deltanoid-dependent. The ED(50) for induction of heterodimerization was 1-2 x 10(-)(9) M for 1alpha,25(OH)(2)D(3) and 0.5 x 10(-)(11) M for 20-epi 1alpha,25(OH)(2)D(3). Mutations in VDR's activation function 2 domain (AF-2) diminished the abilities of 1alpha,25(OH)(2)D(3) to induce a protease-resistant conformation and heterodimerization. These mutations changed neither the potency of 20-epi-1alpha,25(OH)(2)D(3) to induce protease-resistant conformation nor its potency to induce dimerization. Mutations in heptad 9/helix 10 abolished the ability of both 1alpha,25(OH)(2)D(3) and the 20-epi analog to induce dimerization, but not their potency to fold VDR into a protease-resistant conformation. We hypothesize that both the hormone and the analog stabilize receptor conformations that expose VDR's dimerization interface, and that interfaces exposed by these ligands are probably not significantly different. However, the mechanisms by which the two ligands expose the dimerization interface are different with respect to participation of the AF-2 domain.

Ceramide glycosylation potentiates cellular multidrug resistance

Ceramide glycosylation, through glucosylceramide synthase (GCS), allows cellular escape from ceramide-induced programmed cell death. This glycosylation event confers cancer cell resistance to cytotoxic anticancer agents [Liu, Y. Y., Han, T. Y., Giuliano, A. E., and M. C. Cabot. (1999) J. Biol. Chem. 274, 1140-1146]. We previously found that glucosylceramide, the glycosylated form of ceramide, accumulates in adriamycin-resistant breast carcinoma cells, in vinblastine-resistant epithelioid carcinoma cells, and in tumor specimens from patients showing poor response to chemotherapy. Here we show that multidrug resistance can be increased over baseline and then totally reversed in human breast cancer cells by GCS gene targeting. In adriamycin-resistant MCF-7-AdrR cells, transfection of GCS upgraded multidrug resistance, whereas transfection of GCS antisense markedly restored cellular sensitivity to anthracyclines, Vinca alkaloids, taxanes, and other anticancer drugs. Sensitivity to the various drugs by GCS antisense transfection increased 7- to 240-fold and was consistent with the resumption of ceramide-caspase-apoptotic signaling. GCS targeting had little influence on cellular sensitivity to either 5-FU or cisplatin, nor did it modify P-glycoprotein expression or rhodamine-123 efflux. GCS antisense transfection did enhance rhodamine-123 uptake compared with parent MCF-7-AdrR cells. This study reveals that GCS is a novel mechanism of multidrug resistance and positions GCS antisense as an innovative force to overcome multidrug resistance in cancer chemotherapy.

[The trends and preventive strategies of esophageal cancer in high-risk areas of Taihang Mountains, China]

OBJECTIVE

To analyze and predict the trends of incidence and mortality rates of esophageal cancer in areas of Taihang Mountains, and explore the strategies for facilitating the reduction of the incidence and mortality of esophageal cancer.

METHODS

The data were collected from Linxian and Cixian Counties registries between 1988-1997. The trends of the incidence and mortality rates for esophageal cancer had been fitted and predicted by the model of BP (Back Propagation) Neural Networks. Then Linqi Xiang in Linxian County was taken as an example, to determine the power for reducing incidence and mortality of esophageal cancer using endoscopic technology as an early detection and treatment method.

RESULTS

There were slowly declining trends for both incidence and mortality rates during past 10 years in Taihang Mountains. The predicting rates of the esophageal cancer incidence in 2,002 are 115. 70/100,000 for male and 79.88/100,000 for female; mortality rates are 94.00/100,000 and 56.29/100,000 respectively. Both incidence and mortality rates a still in high level. But when using endoscopic technology as an early detection and treatment method, the incidence rate is nearly 1/3 of a control group and the power is 88.30% at the end of eight years. The mortality rate is 1/4 of the control group and power is 89.44% after five years intervention (both powers based on 0.05 significant levels).

CONCLUSIONS

The incidence and mortality rates for esophageal cancer are still on high levels in Taihang Mountains. We should continue to enhance our preventive effort there. After using endoscopic technology as an early detection and treatment method, the incidence and mortality rates will be decreased markedly during 5 to 8 years. It is recommended to implement a large-scale secondary prevention strategy in these areas.

[Vacuole formation and endothelial damage in microvessels after ischemia reperfusion]

AIM

Damage of endothelial cells and adhesion of leukocytes and platelets were studied in rat mesentery microvessels after ischemia reperfusion.

METHODS

The model was made by losing blood and reperfusion from carotid artery in rat. Changes of mesentery microvessels were observed by high magnify microscope.

RESULTS

Leukocytes and platelets adhesions were found in venules and co capillaries 1-3 hours after ischemia reperfusion. Endothelial cells were edema and vascular walls were thickening. Vacuoles formed in intracytoplasm of some vascular endothelium and some bigger endothelial vacuoles prominence toward the luminal surface. Vacuoles liked circle shape and the diameter was 10-30 microm. More vacuoles were found in arterioles, even there were several vacuoles in a arteriole. The biggest vacuole almost occupied 2/3 of vascular lumen.

CONCLUSION

Edema and vacuole formation in vascular endothelium indicate that endothelial cells are injured seriously after ischemia reperfusion.

Developmental study of cytochrome oxidase activity in the brain stem respiratory nuclei of postnatal rats

We utilized cytochrome oxidase (CO) as a marker of neuronal functional activity to examine metabolic changes in brain stem respiratory nuclei of rats from newborn to 21 day of age. The pre-Bötzinger complex (PBC), upper airway motoneurons of nucleus ambiguus (NA(UAM)), ventrolateral nucleus of solitary tract (NTS(VL)), and medial and lateral parabrachial nuclei (PB(M) and PB(L), respectively) were examined at postnatal days (P) 0, 1, 2, 3, 4, 5, 7, 14, and 21. CO histochemistry was performed, and the intensity of CO reaction product was quantitatively analyzed by optical densitometry. In addition, CO histochemistry was combined with neurokinin-1 receptor (NK1R) immunogold-silver staining to doubly label neurons of PBC in P14 animals. The results showed that levels of CO activity generally increased with age in all of the nuclei examined. However, a significant decrease was found in NA(UAM) at P3 (P < 0.01), and a distinct plateau of CO activity was noted at P3 in PBC and at P3 and P4 in NTS(VL), PB(M), and PB(L). Of the neurons examined in PBC, 83% were doubly labeled with CO and NK1R. Of these, CO activity was high in 33.9%, moderate in 27.3%, and light in 38.8% of neurons, suggesting different energy demands in these metabolic groups that may be related to their physiological or synaptic properties. The transient decrease or plateau in CO activity at P3 and P4 implies a period of synaptic adjustment or reorganization during development, when there may be decreased excitatory synaptic drive or increased inhibitory synaptic drive, or both, in these brain stem respiratory nuclei. The adjustment, in turn, may render the system less responsive to respiratory insults. This may bear some relevance to our understanding of pathological events during postnatal development, such as occurs in sudden infant death syndrome.

The sulfonylurea glimepiride regulates intracellular routing of the insulin-receptor complexes through their interaction with specific protein kinase C isoforms

Sulfonylureas may stimulate glucose metabolism by protein kinase C (PKC) activation. Because interaction of insulin receptors with PKC plays an important role in controlling the intracellular sorting of the insulin-receptor complex, we investigated the possibility that the sulfonylurea glimepiride may influence intracellular routing of insulin and its receptor through a mechanism involving PKC, and that changes in these processes may be associated with improved insulin action. Using human hepatoma Hep-G2 cells, we found that glimepiride did not affect insulin binding, insulin receptor isoform expression, and insulin-induced receptor internalization. By contrast, glimepiride significantly increased intracellular dissociation of the insulin-receptor complex, degradation of insulin, recycling of internalized insulin receptors, release of internalized radioactivity, and prevented insulin-induced receptor down-regulation. Association of PKC-betaII and -epsilon with insulin receptors was increased in glimepiride-treated cells. Selective depletion of cellular PKC-betaII and -epsilon by exposure to 12-O-tetradecanoylphorbol-13-acetate (TPA) or treatment of cells with PKC-betaII inhibitor G06976 reversed the effect of glimepiride on intracellular insulin-receptor processing. Glimepiride increased the effects of insulin on glucose incorporation into glycogen by enhancing both sensitivity and maximal efficacy of insulin. Exposing cells to TPA or G06976 inhibitor reversed these effects. Results indicate that glimepiride increases intracellular sorting of the insulin-receptor complex toward the degradative route, which is associated with both an increased association of the insulin receptor with PKCs and improved insulin action. These data suggest a novel mechanism of action of sulfonylurea, which may have a therapeutic impact on the treatment of type 2 diabetes.

The relationship between social support and well-being of rural elderly women

The purpose of this study is to examine the relationship between social support and well-being of rural elderly women. A sample of 284 women aged 60 and older (M = 69.12, SD = 6.40) in a rural area of southern Taiwan completed all interview questions. The Chinese versions of the Personal Resource Questionnaire (PRQ) and the Positive Affect and Negative Affect Scale (PANAS) were used to measure social support and well-being. Content validity of the Chinese versions of the instruments was estimated as satisfactory. The alpha reliability coefficients were .86 for the entire PRQ-85 Part 2 and from .65 to .78 for the subscales. The alpha reliability coefficients were .85 and .65 for the PA subscale and NA subscale respectively. Pearson correlation coefficients were used to examine the relationship between social support and well-being. The findings demonstrated that not only the entire social support but also its five dimensions were positively correlated with positive affect (r ranged from .24 to .48, p < .01) and were inversely correlated with negative affect (r ranged from -.15 to -.21, p < .05 or .01). A substantive intervention design may help verify the effectiveness of social support on elderly women's positive affect and negative affect. Using social support as a strategy to promote these women's well-being, therefore, should be the subject of future study.

Regulation of ligand-induced heterodimerization and coactivator interaction by the activation function-2 domain of the vitamin D receptor

Twenty-epi analogs of 1alpha,25-dihydroxyvitamin D3 (1,25D3) are 100-1000 times more potent transcriptionally than the natural hormone. To determine whether this enhanced activity is mediated through modulation of the dimerization process or through interaction with coactivators, we performed quantitative protein-protein interaction assays with in vitro translated vitamin D receptor (ivtVDR) and fusion proteins containing glutathione-S-transferase (GST) and either the ligand-binding domain of retinoid X receptor (RXRalpha), or the nuclear receptor-interacting domain of the steroid receptor coactivator 1 (SRC-1), or the glucocorticoid receptor-interacting protein 1 (GRIP-1). We found that heterodimerization of the ligand-binding domains of RXRalpha and VDR was primarily deltanoid dependent as was the interaction of VDR with the SRC-1 or with GRIP-1. The ED50 for induction of heterodimerization was 2 nM for 1,25D3 and 0.05 nM for 20-epi-1,25D3. However, the ED50 for induction of VDR interaction with SRC-1 was similar for both 1,25D3 and the 20-epi analog (ED50 = 0.7-1.0 nM) as was the ED50 for ligand-mediated interaction of VDR with GRIP-1 (ED50 = 0.1-0.3 nM). Mutations in heptad 9 diminished both 1,25D3 and the 20-epi analog-mediated dimerization, without changing binding of these ligands to VDR. Mutations in VDR's activation function 2 (AF-2) domain/helix 12 residues diminished the ability of 1,25D3 to induce heterodimerization and interaction with SRC-1. These mutations did not change the ability of 20-epi-1,25D3 to induce dimerization but did diminish its ability to induce interaction with SRC-1. We hypothesize that both the hormone and the analog stabilize receptor conformations that expose VDR's functional interfaces. The mechanisms by which the two ligands expose these functional interfaces differ with respect to participation of the AF-2 domain.

A mammalian cytochrome fused to a chloroplast transit peptide is a functional haemoprotein and is imported into isolated chloroplasts

The small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is a major chloroplast stromal protein that is cytosolically synthesized as a precursor with an N-terminal extension, known as the transit sequence or transit peptide (Tp). The Tp is essential for the post-translational uptake of the precursor by the chloroplast. The Tp is thought to influence the conformation of the precursor protein and to facilitate polypeptide translocation across the chloroplast envelope barrier via a Tp-selective translocon. To address these issues we have devised a novel strategy to generate substrate amounts of a chloroplast targeting sequence as a fusion with the chromogenic globular domain of cytochrome b(5) (Cyt). The chimaeric protein is an ideal probe for investigating the conformation of a preprotein and events surrounding protein import into isolated chloroplasts. The Cyt of liver endoplasmic reticulum was fused at its N-terminus with the Tp of the small subunit of Rubisco of Pisum sativum (pea). To enhance its production by clearance from the cytoplasm of Escherichia coli, the chimaera was engineered by further N-terminal linkage of a prokaryotic secretory signal. Expression of this tripartite fusion resulted in mg quantities of the signal sequence-processed Tp-Cyt protein, which was eventually targeted to the membranes. The chromogenic nature of the chimaera and its localization to the bacterial membrane facilitated the biochemical isolation of the precursor in a soluble and functional form. The purified preprotein displayed spectral and enzymic properties that were indistinguishable from the native parental Cyt, implying an absence of observable influence of the Tp on the conformation of the haemoprotein. The chimaeric precursor was imported into the stroma of the isolated chloroplasts in a dose-dependent manner. Import was also strongly dependent upon exogenously supplied ATP. The stromally imported chimaeric precursor protein was processed to a size characteristic of Cyt.

Prognosis and recurrent patterns in bronchioloalveolar carcinoma

STUDY OBJECTIVE

Bronchioloalveolar carcinoma (BAC) is an uncommon pulmonary neoplasm with various radiologic and clinical presentations. In this article, we analyze the initial radiologic findings, TNM stagings, surgical types, and radiologic features of recurrence, and correlate them with patient survival.

DESIGN

A retrospective review of 93 patients who underwent resection for BAC from February 1989 to May 1999.

PATIENTS

There were a total of 153 patients with BAC diagnosed during this period. Among them, 60 patients (39.2%) had diffuse disease and received medical therapy only, and the remaining 93 patients (60.8%), who had localized disease, underwent surgical resection. Patients who received surgical resection were enrolled in this study.

MEASUREMENTS

Data regarding demographics, presentation symptoms, initial radiologic features, surgical type, tumor staging, recurrence status, radiologic patterns of recurrence, and survival were obtained from all patients.

RESULTS

Female patients were significantly younger than male patients. Patients who were female, nonsmoking, undergoing curative surgery, lobectomy, or bilobectomy, and with early tumor staging and no nodal involvement had a better prognosis. Patients with a right lung tumor had a longer survival than those with a left lung tumor, with borderline significance. Among those who suffered from recurrent diseases, a second resection yielded a better survival. Multivariate analysis showed curative surgery, initial surgical type, recurrence status, radiologic patterns of recurrence, and duration from surgical resection to recurrence all had a significant impact on survival.

CONCLUSIONS

Those patients with localized, early-stage BAC who underwent curative surgery had a better survival. Patients with localized recurrence after the initial surgery warranted a second resection. Those with a diffuse radiologic pattern of recurrence and/or early recurrence had a worse prognosis.

[A new flavonoid glycoside from Allium cepa L. var agrogatum Don]

AIM

To investigate the chemical constituents from the bulb stems of the Chinese medicinal plant Allium cepa L. var. agrogatum Don.

METHODS

The crude extracts of the bulb stem were purified by Sephadex LH-20 chromatography. IR, UV, MS, 1H, 13CNMR, 1H-1H COSY, 1H-13C COSY and HMBC spectra were used to determine the structure of the isolated constituents.

RESULTS

A new compound named quercetin 3'-methoxy-4'-O-beta-D-glucopyranoside(I), together with three known compounds kaempferol(II), quercetin 4'-O-beta-D-glucopyranoside(III) and quercetin 3,4'-di-O-beta-D-glucopyranoside(IV) were isolated.

CONCLUSION

Quercetin 3'-methoxy-4'-O-beta-D-glucopyranoside(I) is a new compound, compounds II-IV were isolated from this plant for the first time.

Expression of an anti-CD3 single-chain immunotoxin with a truncated diphtheria toxin in a mutant CHO cell line

ADP-ribosylating immunotoxins are generally expressed in Escherichia coli and then refolded in vitro. Because the efficiency of the in vitro refolding process decreases with the number of protein domains and internal disulfide bonds, these immunotoxins have been generally limited to single-chain monovalent structures. We now show that using the hamster cell line CHO K1 RE1.22c (J. M. Moehring and T. J. Moehring, 1979, Somat. Cell Genet. 5, 453-468) that has been mutated to ADP-ribosylation insensitivity, a level of 4 microg/ml of a truncated anti-T cell immunotoxin, DT390-scFvUCHT1, can be secreted into the medium. This immunotoxin is glycosylated at the two potential N-linked glycosylation sites in the toxin moiety: positions 16-18 in the A chain and residues 235-237 in the B chain. The glycosylated immunotoxin is relatively nontoxic (IC(50) 4.8 x 10(-10) M). Removal of the N-linked oligosaccharides by N-glycosidase F treatment or mutations at the two N-linked glycosylation sites results in a highly active immunotoxin with an IC(50) of 4 x 10(-12) M toward CD3(+) Jurkat cells. This is a 12-fold increase in toxicity over the same immunotoxin harvested from E. coli periplasm without refolding. A single Asn(235) Ala mutation that removed the B chain glycosylation was nearly as toxic as the double mutant. This suggests that B chain glycosylation is the major cause for the loss of toxicity.

Uncoupling ceramide glycosylation by transfection of glucosylceramide synthase antisense reverses adriamycin resistance

Previous work from our laboratory demonstrated that increased competence to glycosylate ceramide conferred adriamycin resistance in MCF-7 breast cancer cells (Liu, Y. Y., Han, T. Y., Giuliano, A. E. , and M. C. Cabot. (1999) J. Biol. Chem. 274, 1140-1146). This was achieved by cellular transfection with glucosylceramide synthase (GCS), the enzyme that converts ceramide to glucosylceramide. With this, we hypothesized that a decrease in cellular ceramide glycosylation would result in heightened drug sensitivity and reverse adriamycin resistance. To down-regulate ceramide glycosylation potential, we transfected adriamycin-resistant breast cancer cells (MCF-7-AdrR) with GCS antisense (asGCS), using a pcDNA 3.1/his A vector and developed a new cell line, MCF-7-AdrR/asGCS. Reverse transcription-polymerase chain reaction assay and Western blot analysis revealed marked decreases in both GCS mRNA and protein in MCF-7-AdrR/asGCS cells compared with the MCF-7-AdrR parental cells. MCF-7-AdrR/asGCS cells exhibited 30% less GCS activity by in vitro enzyme assay (19.7 +/- 1.1 versus 27.4 +/- 2.3 pmol GC/h/microg protein, p < 0.001) and were 28-fold more sensitive to adriamycin (EC(50), 0.44 +/- 0.01 versus 12.4 +/- 0.7 microM, p < 0. 0001). GCS antisense transfected cells were also 2.4-fold more sensitive to C(6)-ceramide compared with parental cells (EC(50) = 4. 0 +/- 0.03 versus 9.6 +/- 0.5 microM, p < 0.0005). Under adriamycin stress, GCS antisense transfected cells compared with parental cells displayed time- and dose-dependent increases in endogenous ceramide and dramatically higher levels of apoptotic effector, caspase-3. Western blotting showed that adriamycin sensitivity, introduced by asGCS gene transfection, was independent of P-glycoprotein and Bcl-2 expression. In summary, this work shows that transfection of GCS antisense tempers the expression of native GCS and restores cell sensitivity to adriamycin. Therefore, limiting the potential to glycosylate ceramide, which is an apoptotic signal in chemotherapy and radiotherapy, provides a promising approach to combat drug resistance.