Physical/chemical separations in the break-up of highly charged droplets from electrosprays

Highly-charged droplets, as formed by an electrospray process, are known to undergo asymmetric fission to form smaller droplets. We have observed a chemical and physical separation phenomenon that occurs in the droplet break-up process and is related to a compound's surface activity in solution. Two experimental approaches demonstrated that the smaller satellite droplets and the progeny droplets generated by the spray formation and asymmetric fission processes to be surfactant-enriched. These smaller droplets were also effectively separated from the larger primary and residual droplets because of their smaller inertia and high surface charge density, and a region attributed to the initially formed smaller satellite droplets was found to be strikingly confined in a narrow periphery region of the electrospray. The phenomenon may have utility for chemical separations and have significant implications for the sensitivity and selectivity of electrospray ionization-mass spectrometry.

DNA sequencing and genotyping by transcriptional synthesis of chain-terminated RNA ladders and MALDI-TOF mass spectrometry

Sets of RNA ladders can be synthesized by transcription of a bacteriophage-encoded RNA polymerase using 3'-deoxynucleotides as chain terminators. These ladders can be used for sequencing of DNA. Using a nicked form of phage SP6 RNA polymerase in this study substantially enhanced yields of transcriptional sequencing ladders. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) of chain-terminated RNA ladders allowed DNA sequence determination of up to 56 nt. It is also demonstrated that A-->G and C-->T variations in heterozygous and homozygous samples can be unambiguously identified by the mass spectrometric analysis. As a step towards single-tube sequencing reactions, alpha-thiotriphosphate nucleotide analogs were used to overcome problems caused by chain terminator-independent, premature termination and by the small mass difference between natural pyrimidine nucleotides.

Dopamine-dependent synaptic plasticity in striatum during in vivo development

The neurotransmitters dopamine (DA) and glutamate in the striatum play key roles in movement and cognition, and they are implicated in disorders of the basal ganglia such as Parkinson's disease. Excitatory synapses in striatum undergo a form of developmental plasticity characterized by a decrease in glutamate release probability. Here we demonstrate that this form of synaptic plasticity is DA and DA D2 receptor dependent. Analysis of spontaneous synaptic responses indicates that a presynaptic mechanism involving inhibition of neurotransmitter release underlies the developmental plasticity. We suggest that a major role of DA in the striatum is to initiate mechanisms that regulate the efficacy of excitatory striatal synapses, producing a decrease in glutamate release.

Eicosanoid activation of extracellular signal-regulated kinase1/2 in human epidermoid carcinoma cells

12(S)-Hydroxyeicosatetraenoic acid (12(S)-HETE), a 12-lipoxygenase metabolite of arachidonic acid, has multiple effects on tumor and endothelial cells, including stimulation of invasion and angiogenesis. However, the signaling mechanisms controlling these physiological processes are poorly understood. In a human epidermoid carcinoma cell line (i.e. A431), 12(S)-HETE activates extracellular signal-regulated kinases 1/2 (ERK1/2), which is mediated by upstream kinases MEK and Raf. 12(S)-HETE stimulates phosphorylation of phospholipase Cgamma1 and activity of protein kinase Calpha (PKCalpha). In addition, independent of PKC 12(S)-HETE increases tyrosine phosphorylation of Shc, and Grb2, stimulates association between Shc and Src, and increases the activity of Ras, via Src family kinases. Furthermore, at low (10-100 nm) concentrations 12(S)-HETE counteracts epidermal growth factor-stimulated activation of ERK1/2 via stimulating protein tyrosine phosphatases. We also present evidence that 12(S)-HETE stimulates ERK1/2 via G proteins and that A431 cells have multiple binding sites for 12(S)-HETE. Finally, inhibition of 12-lipoxygenase induced apoptosis of A431 cells, which was reversed by addition of exogenous 12(S)-HETE. Collectively we demonstrate that the activation of ERK1/2 by 12(S)-HETE may be regulated by multiple receptors triggering PKC-dependent and PKC-independent pathways in A431 cells.

Detailed mapping of prostate carcinoma foci: biopsy strategy implications

BACKGROUND

Prostate carcinoma exhibits considerable anatomic heterogeneity. Detailed characterization of prostate carcinoma distribution could lead to improved detection procedures and biopsy strategies. We mapped all 607 tumor foci from 180 serially sectioned whole mount radical prostatectomy specimens and used a computer algorithm to plot and summarize the distribution of these foci. We investigated whether specimen and clinical variables predicted differences in tumor distribution.

METHODS

The volume and anatomic location of each tumor focus were determined and digitized. A computer-based algorithm was used to fit the digitized tumor foci to a paradigm prostate. Pseudo-color summary plots of tumor distribution then were computed for selected cases.

RESULTS

Of the 180 specimens, 149 (83%) specimens had more than one cancer focus. Most foci (448 of 607 tumor foci, 74%) were in the peripheral zone (PZ). PZ foci near the apex had a significant midline component. Toward the base, PZ foci diverged laterally. Only 3 (2%) of 180 specimens contained foci solely in the transition zone (TZ). Total TZ cancer volume was </= 0.5 cm(3) in 55% (52 of 94) of patients. Computer plots of patients with T1c classification (UICC/AJCC) and specimen Gleason score </= 6 had greater proportions of TZ tumor.

CONCLUSIONS

Almost all TZ foci occurred with PZ foci. The small volume of most TZ foci may explain the ineffectiveness of TZ biopsies to detect additional cancers during screening. Further, our results suggested that biopsies may be more effective if laterally directed biopsy samples are obtained nearer to the base of the prostate and if apical biopsy samples are obtained more medially.

Anti-HBV effect of targeted antisense RNA against HBV C gene

OBJECTIVE

To investigate the anti-HBV effect of targeted antisense RNA to hepatic cells.

METHODS

pREP4-aC which would transcript antisense RNA against HBV C gene in eukaryotic cells were delivered into 2.2.15 cells by glactosylated poly-L-lisine (Gal-PLL), and the positive cells were selected. HBsAg, HBeAg and HBV DNA produced by 2. 2.15 cells were detected with ELISA or Southern blot during the experiment, and the cytotoxicity of targeted antisense on 2.2.15 cells was observed.

RESULTS

The inhibition effect on HBsAg, HBeAg and HBV DNA occurred at the 24th hour after delivery and reached the highest level at the 6th day, and kept at lest two months. No cytotoxicity on 2.2.15 cells was observed.

CONCLUSION

The targeted antisense against HBV C gene by delivery of Gal-PLL could effectively inhibit the antigen expression of HBV and DNA replication.

Mass spectrometry of single-stranded restriction fragments captured by an undigested complementary sequence

In this report, we describe a simple and accurate method to analyze restriction fragments using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The two complementary strands of restriction fragments are separated through hybridization to a capture probe, which is a single-stranded undigested fragment. Using the biotin-streptavidin linkage, the hybrid is immobilized on streptavidin-coated magnetic beads. After conditioning the captured restriction fragments, they are eluted from the probe and their molecular weights are determined. The proposed method greatly improves the quality, and reduces the complexity of the mass spectrum by analyzing only one of the complementary strands of restriction fragments.

Eicosanoid regulation of angiogenesis in human prostate carcinoma and its therapeutic implications

Cancer of the prostate is the most commonly diagnosed cancer in America. There are several lines of evidence implicating the involvement of arachidonate 12-lipoxygenase, an enzyme metabolizing arachidonic acid to form 12(S)-hydroxyeicosatetraenoic acid (HETE), in prostate cancer progression. First, as prostate cancer reaches a more advanced stage, the level of 12-lipoxygenase expression is increased. Second, overexpression of 12-lipoxygenase in human prostate cancer cells stimulates angiogenesis and tumor growth. Third, an inhibitor of 12-lipoxygenase has been found effective against metastatic prostate tumor growth, and the inhibition of 12-lipoxygenase is related with the reduction of tumor angiogenesis. Collectively, these studies suggest that 12-lipoxygenase regulates tumor angiogenesis in prostate cancer and that inhibition of 12-lipoxygenase is a novel therapeutic approach for the treatment of prostate cancers.

Eicosanoid regulation of angiogenesis: role of endothelial arachidonate 12-lipoxygenase

Angiogenesis, the formation of new capillaries from preexisting blood vessels, is a multistep, highly orchestrated process involving vessel sprouting, endothelial cell migration, proliferation, tube differentiation, and survival. Eicosanoids, arachidonic acid (AA)-derived metabolites, have potent biologic activities on vascular endothelial cells. Endothelial cells can synthesize various eicosanoids, including the 12-lipoxygenase (LOX) product 12(S)-hydroxyeicosatetraenoic acid (HETE). Here we demonstrate that endogenous 12-LOX is involved in endothelial cell angiogenic responses. First, the 12-LOX inhibitor, N-benzyl-N-hydroxy-5-phenylpentanamide (BHPP), reduced endothelial cell proliferation stimulated either by basic fibroblast growth factor (bFGF) or by vascular endothelial growth factor (VEGF). Second, 12-LOX inhibitors blocked VEGF-induced endothelial cell migration, and this blockage could be partially reversed by the addition of 12(S)-HETE. Third, pretreatment of an angiogenic endothelial cell line, RV-ECT, with BHPP significantly inhibited the formation of tubelike/cordlike structures within Matrigel. Fourth, overexpression of 12-LOX in the CD4 endothelial cell line significantly stimulated cell migration and tube differentiation. In agreement with the critical role of 12-LOX in endothelial cell angiogenic responses in vitro, the 12-LOX inhibitor BHPP significantly reduced bFGF-induced angiogenesis in vivo using a Matrigel implantation bioassay. These findings demonstrate that AA metabolism in endothelial cells, especially the 12-LOX pathway, plays a critical role in angiogenesis.

Identification of 12-lipoxygenase interaction with cellular proteins by yeast two-hybrid screening

The platelet isoform of 12-lipoxygenase (12-LOX) is expressed in a variety of human tumors. 12-LOX metabolizes arachidonic acid to 12(S)-hydroxyeicosateraenoic acid (12(S)-HETE), which induces a number of cellular responses associated with tumor progression and metastasis. Little is known about 12-LOX regulation and no direct regulators of 12-LOX activity have been identified. To identify potential regulators of 12-LOX, we isolated cDNAs encoding 12-LOX interacting proteins using the yeast two-hybrid system. We screened a yeast two-hybrid interaction library from human epidermoid carcinoma A431 cells and identified four cellular proteins that interact specifically with 12-LOX. We identified type II keratin 5, lamin A, the cytoplasmic domain of integrin beta4 subunit and a phosphoprotein C8FW as 12-LOX interacting proteins. Here, we demonstrated that keratin 5, a 58 kD protein required for formation of 8 nm intermediate filaments, binds to 12-LOX in human tumor cells and may contribute to the regulated trafficking of 12-LOX. We also showed that lamin A binds 12-LOX in human tumor cells. These proteins provide the first candidate regulators of 12-LOX.

[The relationship of brainstem auditory evoked potential to cerebral blood flow volume in with vertebrobasilar transient ischemic vertigo]

This study was aimed at the relationship of brain-stem auditory evoked potential(BAEP) with cerebral blood flow(CBF) volume and vascular pathological changes in patients with vertebro-basilar transient ischemic vertigo (VBTIV). 65 patients were examined by magnetic resonance angiography(MRA), transcranial Dopplar(TCD) and BAEP; 26 controls were examined by MRA and TCD. In the patient group, MRA showed that vascular pathological changes were obvious in 50 patients, and obscure or absent in 15 patients. The CBF volume [112.3-278.9 ml/min (2s)] of control group was higher than that (48.0-262.0 ml/min) of the patients group (t = 2.43, P < 0.01) in which 15 patients had low CBF volume and 50 patients had normal CBF volume. The BAEP of 47(72.3%) patients was abnormal. Out of 15 patients with low CBF volume, 14(93.3%) had abnormal BAEP, but out of 50 patients with normal CBF volume, only 33(66%) patients had abnormal BAED (chi 2 = 4.34, P < 0.05). In the 50 patients with obscure obvious vascular pathological changes, 40(80%) patients had abnormal BAEP, but in the 15 patients with obscure or without the changes, only 7(43.3%) patients had abnormal BAEP (chi 2 = 4.86, P < 0.05). These results suggested that there might be a close relationship of BAEP with CBF volume and vascular pathological changes.

Thromboxane A(2) regulation of endothelial cell migration, angiogenesis, and tumor metastasis

Prostaglandin endoperoxide H synthases and their arachidonate products have been implicated in modulating angiogenesis during tumor growth and chronic inflammation. Here we report the involvement of thromboxane A(2), a downstream metabolite of prostaglandin H synthase, in angiogenesis. A TXA(2) mimetic, U46619, stimulated endothelial cell migration. Angiogenic basic fibroblast growth factor (bFGF) or vascular endothelial growth factor (VEGF) increased TXA(2) synthesis in endothelial cells three- to fivefold. Inhibition of TXA(2) synthesis with furegrelate or CI reduced HUVEC migration stimulated by VEGF or bFGF. A TXA(2) receptor antagonist, SQ29,548, inhibited VEGF- or bFGF-stimulated endothelial cell migration. In vivo, CI inhibited bFGF-induced angiogenesis. Finally, development of lung metastasis in C57Bl/6J mice intravenously injected with Lewis lung carcinoma or B16a cells was significantly inhibited by thromboxane synthase inhibitors, CI or furegrelate sodium. Our data demonstrate the involvement of TXA(2) in angiogenesis and development of tumor metastasis.

Evi-1 and MDS1-Evi-1 genes in pathogenesis of myelodysplastic syndromes and post-MDS acute myeloid leukemia

OBJECTIVE

To investigate expression of Evi-1 and MDS1-Evi-1 genes in myelodysplastic syndromes (MDS) and post-MDS acute myeloid leukemia (post-MDS AML), and its role in pathogenesis or progression of MDS and post-MDS AML.

METHODS

Expression of Evi-1 and MDS1-Evi-1 genes was examined in 31 MDS, 11 post-MDS AML, and 34 de novo AML patients by a semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

Evi-1 expression was not detected in bone marrow samples of 8 normal controls, but low MDS1-Evi-1 expression levels (MDS1-Evi-1/GAPDH < 0.1) were detected in 3 of the 8 controls. Evi-1 RNA was expressed in 1 of 8 RA, 8 of 13 RAEB and 6 of 9 RAEB-T patients, and the percentage of Evi-1 expression in RAEB(T) patients was higher than that in RA (P < 0.05). MDS1-Evi-1 expression was detected in 5 of 8 RA, 9 of 13 RAEB and 5 of 9 RAEB-T patients, and MDS1-Evi-1 expression levels (MDS1-Evi-1/GAPDH > 0.1) were markedly higher than those in the controls. Evi-1 expression was gradually increased in 4 of 5 RAEB-T patients with transformation from MDS to AML. The percentages of Evi-1 and MDS1-Evi-1 expression in post-MDS AML patients were significantly (P < 0.01 and P < 0.05 respectively) higher than those in de novo AML. The colonies of hematopoietic progenitor cells were decreased in Evi-1 and MDS1-Evi-1-positive MDS patients as compared with those in Evi-1 and MDS1-Evi-1-negative patients.

CONCLUSION

Abnormal expression of the Evi-1 gene and overexpression of MDS1-Evi-1 gene may play a role in the pathogenesis or progression of MDS and post-MDS AML.

The beta4 integrin subunit rescues A431 cells from apoptosis through a PI3K/Akt kinase signaling pathway

To study whether alpha6beta4 integrin regulates apoptosis, human A431 cells were plated on bacteria plates in the presence or absence of mAb beta4. In the absence of mAb beta4, A431 cells demonstrated morphological characteristics of apoptosis by 24 h and most cells died by 48 h. In contrast, in the presence of mAb beta4, cells remained viable, and at the end of 48 h, 70-80% of cells survived. Treatment of A431 cells with mAb beta4 resulted in tyrosine phosphorylation of the p85 subunit of PI3 kinase; PI3 kinase activity increased within 15 min and peaked at 60 min. Stimulation of beta4 in A431 cells resulted in a time-dependent phosphorylation of Akt with a concomitant and parallel phosphorylation of Bad. Inactivation of PI3 kinase with inhibitors blocked the anti-apoptotic effect induced by mAb beta4. These are the first results to suggest that ligation of alpha6beta4 integrin protects cells from apoptosis through a PI3K/Akt kinase signaling pathway.

ADP-ribosylation factor 6 and endocytosis at the apical surface of Madin-Darby canine kidney cells

We report that the small GTPase, ADP-ribosylation factor 6 (ARF6), is present only on the apical surface of polarized MDCK epithelial cells. Overexpression of a mutant of ARF6, ARF6-Q67L, which is predicted to be in the GTP-bound form, stimulates endocytosis exclusively at this surface. Surprisingly, overexpression of the mutant ARF6-T27N, which is predicted to be in the GDP-bound form, also stimulated apical endocytosis, though to a lesser extent. ARF6-stimulated endocytosis is inhibited by a dominant-negative form of dynamin, or a dominant-negative hub fragment of clathrin heavy chain, indicating that it is mediated by clathrin. Correspondingly, overexpression of either mutant of ARF6 leads to an increase in the number of clathrin-coated pits at the apical plasma membrane. When ARF6-Q67L is overexpressed in the presence of the dominant-negative dynamin, the ARF6-Q67L colocalizes with clathrin and with IgA bound to its receptor. We conclude that ARF6 is an important modulator of clathrin-mediated endocytosis at the apical surface of epithelial cells.

Chip-based genotyping by mass spectrometry

Silicon chips with immobilized target DNAs were used for accurate genotyping by mass spectrometry. Genomic DNAs were amplified with PCR, and the amplified products were covalently attached to chip wells via N-succinimidyl (4-iodoacetyl)aminobenzoate (SIAB) chemistry. Primer annealing, extension, and termination were performed on a 1-microl scale directly in the chip wells in parallel. Diagnostic products thus generated were detected in situ by using matrix-assisted laser desorption ionization mass spectrometry. This miniaturized method has the potential for accurate, high-throughput, low-cost identification of genetic variations.

[Nestin expression during P19 neuron differentiation]

Mouse nestin, an intermediate filament gene, is transiently expressed during the development of the central nervous system. In order to find the clue of its function during neural development, we tried to find out the gene expression pattern during the neuronal differentiation of P19 EC cells induced RA. RT-PCR showed that nestin was transiently expressed during P19 neuron differentiation, with a peak at day 4 of this process. However, BMP4, a neural precursor cell marker, was transiently expressed with its highest level at day 6, while NF160 kD a terminal differentiated neuronal marker, was increasingly expressed during the whole process. These results implied that nestin might play some roles during the process of neural progenitor cells differentiating into neural precursor cells. Moreover, immunostaining showed that nestin was located in the neurite and the growth cone of the P19 neuron, suggesting that nestin might be also involved in the process of the establishment of neural connection.

Comparison of prostate biopsy schemes by computer simulation

OBJECTIVES

To compare the ability of different biopsy schemes to detect cancer and predict tumor volume using our previously described prostate biopsy simulation system. In addition, we used the simulation system to evaluate the optimal location of transition zone biopsies.

METHODS

Digital reconstructions of 180 radical prostatectomy specimens were used. Forty simulations were performed on each prostate for 10 biopsy schemes, including a previously reported five-region peripheral zone biopsy pattern and a new 11-core multisite-directed scheme consisting of sextant, two transition zone, one midline, and two anterior horn biopsies. For simulation of the transition zone biopsies, paired near-midline biopsies were simulated, with needle insertion points from the apex to the base of the prostate and with needle advances of 1 to 4 cm before firing. A total of 1,180,800 individual biopsy tracks were simulated.

RESULTS

The 11-core multisite-directed biopsy scheme had the highest detection rate for cancers greater than 0.5 cc. This scheme reliably detected cancer in 94% (138 of 147) of the cases. These results were significantly better than those of the sextant biopsy scheme (P <0.001) and the five-region 18-core peripheral zone scheme (P = 0.03). Compared with other schemes, there were increases in small-volume (0.5 cc or less) cancer detection by both the 11-core multisite-directed and five-region schemes, but they were not statistically significant. The multisite and the sextant plus four transition zone biopsy schemes had the best correlation of mean total core cancer length with total cancer volume. In the simulation of the transition zone biopsies, the highest detection rate was observed when the biopsies were initiated at the most apical section and inserted for a depth of 3 cm before firing.

CONCLUSIONS

Our simulation results suggest that the detection rate of prostate biopsies is not related solely to the number of cores taken. Core placement (the regions of the prostate from which samples are taken) is also important. The 11-core multisite-directed biopsy scheme performed the best, with improved cancer detection rates and tumor volume correlation over other schemes. On the basis of our simulations, this scheme has been chosen for clinical evaluation.

Prostate cancer detection: relationship to prostate size

OBJECTIVES

It has been suggested that the lower detection rate for cancer in large prostates is due to the smaller proportion of tissue sampled. To examine this hypothesis, we evaluated whole-mount radical prostatectomy specimens in which the volume of cancer had been determined. We correlated cancer volume to overall gland volume. In addition, we performed stochastic computer simulations of parasagittal sextant biopsies on the same group of radical prostatectomy specimens. We correlated the likelihood of a positive cancer biopsy simulation with tumor volume and gland size.

METHODS

Six hundred seven tumor foci from 180 serially sectioned whole-mount prostatectomy specimens were mapped and digitized. Tumor volume was calculated by a step-section planimetry algorithm. Before sectioning, each gland was weighed. Systematic parasagittal sextant biopsies were computer simulated for each case. For each prostate, 40 simulations were performed, with random variations in biopsy location programmed for each run. Overall cancer detection by biopsy was considered positive if 90% of the 40 simulation runs were positive for cancer. Chi-square tests were used to evaluate statistical significance.

RESULTS

Small-volume cancers (0.5 cc or less) were twice as frequent in large glands greater than 50 g (P = 0.03). These small-volume tumors comprised 33% (13 of 40) of cancers in prostates greater than 50 g, 16% (5 of 31) in glands less than 30 g, and 14% (15 of 109) in glands 30 to 50 g. The rate of positive sextant biopsy simulation was lower in glands greater than 50 g than in glands 50 g or less (48% versus 67%, P<0.03). Smaller cancers were much less likely to be detected in the simulations. The simulation detection rate for cancers 0.5 cc or less was 18% (6 of 33), compared with a detection rate of 73% (107 of 147) for cancers greater than 0.5 cc (P<0.00001).

CONCLUSIONS

The observed lower cancer detection rate in large glands is a result of the higher proportion of low-volume cancers in these glands. This suggests that large prostates are more likely to be biopsied because of an elevated prostate-specific antigen value resulting from benign elements of the gland and not from a significant cancer. Increasing the number of cores solely to compensate for increased prostate size risks a disproportionate increased detection of small-volume tumors with a low clinical likelihood of progression.

Redundant and distinct functions for dynamin-1 and dynamin-2 isoforms

A role for dynamin in clathrin-mediated endocytosis is now well established. However, mammals express three closely related, tissue-specific dynamin isoforms, each with multiple splice variants. Thus, an important question is whether these isoforms and splice variants function in vesicle formation from distinct intracellular organelles. There are conflicting data as to a role for dynamin-2 in vesicle budding from the TGN. To resolve this issue, we compared the effects of overexpression of dominant-negative mutants of dynamin-1 (the neuronal isoform) and dynamin-2 (the ubiquitously expressed isoform) on endocytic and biosynthetic membrane trafficking in HeLa cells and polarized MDCK cells. Both dyn1(K44A) and dyn2(K44A) were potent inhibitors of receptor-mediated endocytosis; however neither mutant directly affected other membrane trafficking events, including transport mediated by four distinct classes of vesicles budding from the TGN. Dyn2(K44A) more potently inhibited receptor-mediated endocytosis than dyn1(K44A) in HeLa cells and at the basolateral surface of MDCK cells. In contrast, dyn1(K44A) more potently inhibited endocytosis at the apical surface of MDCK cells. The two dynamin isoforms have redundant functions in endocytic vesicle formation, but can be targeted to and function differentially at subdomains of the plasma membrane.

Platelet-type 12-lipoxygenase in a human prostate carcinoma stimulates angiogenesis and tumor growth

Previously, we found a positive correlation between the expression of platelet-type 12-lipoxygenase (12-LOX) and the progression of human prostate adenocarcinoma (PCa; Gao et al., Urology, 46: 227-237, 1995). To determine the role of 12-LOX in PCa progression, we generated stable 12-LOX-transfected PC3 cells, which synthesize high levels of 12-LOX protein and 12(S)-hydroxyeicosatetraenoic acid metabolite. In vitro, 12-LOX-transfected PC3 cells demonstrated a proliferation rate similar to neo controls. However, following s.c. injection into athymic nude mice, 12-LOX-transfected PC3 cells formed larger tumors than did the controls. Decreased necrosis and increased vascularization were observed in the tumors from 12-LOX-transfected PC3 cells. Both endothelial cell migration and Matrigel implantation assays indicate that 12-LOX-transfected PC3 cells were more angiogenic than their neo controls. These data indicate that 12-LOX stimulates human PCa tumor growth by a novel angiogenic mechanism.

[Management of abnormal blood vessels of donor kidney in renal transplantation (report of 128 cases)]

The experience on management of abnormal blood vessels in 128 cases of donor kidney during the tailoring operation was reported. The various techniques used for different types of abnormal arteries and veins, and the critical points which should be paid attention to have been discussed. It was concluded that the multiple renal arteries should be treated in a single renal artery and anastomosed with internal iliac artery or/and external iliac artery. The appropriate management given to abnormal renal blood vessels during the tailoring operation may shorten the warm ishemia time, ensure the renal blood supply, reduce the renal vasular complication, and promote the recovery of renal function.

A crucial role for the mitogen-activated protein kinase pathway in nicotinic cholinergic signaling to secretory protein transcription in pheochromocytoma cells

The mitogen-activated protein kinase (MAPK) pathway plays a pivotal role in intracellular signaling, and this cascade may impinge on cAMP response elements (CREs) of target genes. Both the MAPK pathway and chromogranin A expression may be activated by cytosolic calcium influx, and calcium-dependent signals map onto the chromogranin A promoter proximal CRE. We therefore probed the role of the MAPK pathway in chromogranin A biosynthesis after secretory stimulation of PC12 pheochromocytoma cells by the nicotinic cholinergic pathway, the physiological secretory trigger. Chemical inhibition of either MAPK or MAPK kinase blocked the response of a transfected chromogranin A promoter to nicotine or protein kinase C activation [by phorbol-12-myristate-13-acetate (PMA)], although nicotine-evoked catecholamine secretion was unaffected. Activation of the MAP kinase cascade (Ras, Raf, MAPK, or CREB kinase) by cotransfection of pathway components stimulated the chromogranin A promoter. Cotransfection of MAPK pathway dominant negative mutants (for Raf, MAPK, or CREB kinase) blocked nicotinic or PMA activation of chromogranin A, although a dominant negative Ras mutant was without effect. MAPK pathway enzymatic activity was stimulated by both nicotine and PMA. Point mutations of the chromogranin A CRE suggested that this element was necessary in cis for stimulation by nicotine, PMA, or chemical activation of the MAPK pathway. Transfer of the CRE to a heterologous promoter conferred inducibility by not only nicotine or cAMP but also MAPK activation. Expression of the CREB antagonist KCREB blocked the response of the chromogranin A promoter to nicotine, cAMP, or MAPK pathway activation by either chemical stimulation or cotransfection of active cascade components. Chromogranin A mRNA responded to MAPK pathway manipulation in a fashion similar to the transfected chromogranin A promoter, in both direction and magnitude. We conclude that the MAPK pathway is a necessary intermediate in signaling from the nicotinic receptor to secretory protein transcription, although not to catecholamine secretion. In trans, this response seems to involve the following signal cascade: protein kinase C --> Raf --> MAPK kinase --> MAPK --> CREB kinase --> CREB. In cis, activation by the cascade maps onto the chromogranin A promoter proximal CRE, which is both necessary and sufficient to confer the response.

Effects of sildenafil on the relaxation of human corpus cavernosum tissue in vitro and on the activities of cyclic nucleotide phosphodiesterase isozymes

PURPOSE

Sildenafil, an inhibitor of cGMP-specific phosphodiesterase 5 (PDE5), is currently undergoing evaluation as an oral therapy for penile erectile dysfunction. The aims of this study were to investigate the mechanism of action of sildenafil on the neurogenic relaxation of human corpus cavernosum (HCC) in vitro and to determine the activity of sildenafil against a full range of PDE isozymes.

MATERIALS AND METHODS

Strips of HCC tissue were precontracted with phenylephrine. Relaxation responses resulting from electrical field stimulation (EFS) were then determined in the presence and absence of sildenafil. The effects of sildenafil on PDE1 to 5 prepared from human tissues and PDE6 from bovine retina were determined by measuring the conversion of [3H]-cGMP or [3H]-cAMP to their respective [3H]-5'-mononucleotides.

RESULTS

Sildenafil (0.001 to 1 microM) enhanced the EFS-induced, nitric oxide (NO) dependent, relaxation of HCC in a concentration-dependent manner to a maximum of 3 times the pretreatment level at 1 microM sildenafil. Compared with zaprinast, an early PDE5 inhibitor, sildenafil was approximately 240-fold more potent, inhibiting PDE5 from HCC with a geometric mean IC50 of 3.5 nM. For sildenafil, IC50 values for inhibition of PDE1 to 4 were 80 to more than 8500 times greater than that for PDE5 and the IC50 for PDE6 (33 nM) was approximately 9-fold greater.

CONCLUSIONS

The data support the proposal that enhancement of penile erection by sildenafil in patients with erectile dysfunction involves potentiation of the NO-stimulated cGMP signal mediating relaxation of cavernosal smooth muscle during sexual stimulation. Sildenafil is a potent inhibitor of PDE5 from HCC, with high selectivity for PDE5 relative to other PDE isozymes.

Effects of sildenafil on the relaxation of human corpus cavernosum tissue in vitro and on the activities of cyclic nucleotide phosphodiesterase isozymes

PURPOSE

Sildenafil, an inhibitor of cGMP-specific phosphodiesterase 5 (PDE5), is currently undergoing evaluation as an oral therapy for penile erectile dysfunction. The aims of this study were to investigate the mechanism of action of sildenafil on the neurogenic relaxation of human corpus cavernosum (HCC) in vitro and to determine the activity of sildenafil against a full range of PDE isozymes.

MATERIALS AND METHODS

Strips of HCC tissue were precontracted with phenylephrine. Relaxation responses resulting from electrical field stimulation (EFS) were then determined in the presence and absence of sildenafil. The effects of sildenafil on PDE1 to 5 prepared from human tissues and PDE6 from bovine retina were determined by measuring the conversion of [3H]-cGMP or [3H]-cAMP to their respective [3H]-5'-mononucleotides.

RESULTS

Sildenafil (0.001 to 1 microM) enhanced the EFS-induced, nitric oxide (NO) dependent, relaxation of HCC in a concentration-dependent manner to a maximum of 3 times the pretreatment level at 1 microM sildenafil. Compared with zaprinast, an early PDE5 inhibitor, sildenafil was approximately 240-fold more potent, inhibiting PDE5 from HCC with a geometric mean IC50 of 3.5 nM. For sildenafil, IC50 values for inhibition of PDE1 to 4 were 80 to more than 8500 times greater than that for PDE5 and the IC50 for PDE6 (33 nM) was approximately 9-fold greater.

CONCLUSIONS

The data support the proposal that enhancement of penile erection by sildenafil in patients with erectile dysfunction involves potentiation of the NO-stimulated cGMP signal mediating relaxation of cavernosal smooth muscle during sexual stimulation. Sildenafil is a potent inhibitor of PDE5 from HCC, with high selectivity for PDE5 relative to other PDE isozymes.

Sequencing exons 5 to 8 of the p53 gene by MALDI-TOF mass spectrometry

Matrix-assisted laser desorption ionization time of flight mass spectrometry was used to sequence exons 5 to 8 of the human p53 gene. A single tube procedure was established for target amplification and mass spectrometric (MS) sequencing. The MS sequencing scheme is designed for high throughput and parallel sample processing, and is amenable to full automation. Reliable sequencing data were obtained using fmol sample amounts. The high resolution and accuracy of MS sequencing was demonstrated by direct sequencing of a heterozygous template.

Optimization of prostate biopsy strategy using computer based analysis

PURPOSE

We evaluated and optimized the detection of cancer by prostate biopsies. We developed a stochastic computer simulation model of ultrasound guided biopsies using mathematically reconstructed radical prostatectomy specimens. Use of this technique allows rapid evaluation of a variety of factors for their effect on prostate biopsy results. We used this model to analyze the effectiveness of sextant biopsies, which have been widely adopted in clinical practice. We also analyzed other biopsy schemes.

MATERIALS AND METHODS

A total of 607 tumor foci from 180 serially sectioned whole mount radical prostatectomy specimens was mapped and digitized. The cancers had been clinically diagnosed by a variety of biopsy strategies. Simulated parasagittal sextant biopsies were performed for each case. Forty simulation runs (each consisting of a set of 6 biopsies) were performed for each prostate, with realistic random variations in sextant biopsy localization programmed in each run. Cancer detection by biopsy was considered reliable if 90% of the simulation runs for each prostate were positive for cancer. A summary algorithm was used to map the tumor foci.

RESULTS

Simulation of sextant biopsies demonstrated reliably detected cancer in only 107 of 147 patients (73%) in whom total tumor volume was greater than 0.5 cc. There was little correlation between total length of cancer in biopsy cores and tumor volume. Change of biopsy angle from 30 to 45 degrees did not result in significantly increased detection rates. Similarly, placing all biopsies more laterally did not increase overall detection rates. When we mapped tumor foci from the 40 cases in which sextant biopsies did not reliably detect tumor, we found that the foci were distributed in areas not biopsied by the sextant method, that is the transition zone, midline peripheral zone and inferior portion of the anterior horn of the peripheral zone. A 10-core biopsy scheme incorporating these areas as well as the posterolateral prostate reliably detected cancer in 141 of 147 patients (96%) with total tumor volumes greater than 0.5 cc.

CONCLUSIONS

Prostate cancer of significant volume can be present in areas not sampled by standard sextant biopsies. Biopsies of the transition zone, midline peripheral zone and inferior portion of the anterior horn of the peripheral zone should be considered for re-biopsy strategy after negative sextant biopsies. Sampling of these additional areas also can be incorporated in an initial biopsy scheme to increase overall initial rates of detection of prostate cancer.

Stimulus coupling to transcription versus secretion in pheochromocytoma cells. Convergent and divergent signal transduction pathways and the crucial roles for route of cytosolic calcium entry and protein kinase C

How do chromaffin cell secretory stimuli program resynthesis of secreted peptides and amines? We previously showed that the physiologic nicotinic cholinergic signal for secretion also activates the biosynthesis of chromogranin A, the major protein released with catecholamines. Here, we examine signal transduction pathways whereby secretory stimuli influence exocytotic secretion versus chromogranin A transcription. Both secretion and transcription depended on initial nicotinic-triggered sodium entry into the cytosol, followed by calcium entry through -type voltage-gated channels. When calcium entered through -type channels, activation of secretion paralleled activation of transcription (r = 0.897, P = 0.002). Calcium entry from intracellular stores or through calcium ionophore channels activated secretion, though not transcription. Nicotinic-stimulated transcription depended upon protein kinase C activation; nicotine caused translocation of protein kinase C to the cell membrane fraction, and inhibition of protein kinase C blocked activation of transcription, while activation of protein kinase C mimicked nicotine effects. Transcriptional responses to both nicotine and protein kinase C mapped principally onto the chromogranin A promoter's cAMP response element (TGACGTAA; CRE box). KCREB, a dominant negative mutant of the CRE-binding protein CREB, blunted activation of chromogranin A transcription by nicotine, phorbol ester, or membrane depolarization. We conclude that activation of chromogranin A transcription by secretory stimulation in chromaffin cells is highly dependent upon precise route of calcium entry into the cytosol; transcription occurred after entry of calcium through -type channels on the cell surface, and was mediated by protein kinase C activation. The trans-acting factor CREB ultimately relays the secretory signal to the chromogranin A promoter's CRE box in cis.

[Clonal analysis of blood cells using X-linked HUMARA gene polymorphism]

OBJECTIVE

To explore the method for clonal analysis of blood cells.

METHODS

Thirty female AML patients and 20 normal female subjects were analysed by the analysis of X-linked HUMARA gene polymorphism and methylation pattern.

RESULTS

The heterozygote rate of HUMARA gene in Chinese women was 88% and the gene had a stable methylation pattern. Out of 20 control females, 17 were heterozygotes and among them 15 were polyclonal, 2 (11.8%) showed skewed X-inactivation. All heterozygote AML were clonal hematopoiesis.

CONCLUSION

HUMARA gene polymorphism is a good marker for clonality analysis of blood cells.

Monodisperse Electrosprays of Low Electric Conductivity Liquids in the Cone-Jet Mode

An experimental investigation was performed on electrosprays of low electric conductivity liquids (heptane with different amounts of an antistatic additive) that were operated in the cone-jet mode. The effects of liquid flow rate, applied voltage, and liquid electric conductivity on droplet size and spray monodispersity were systematically investigated. The droplet size was found to be dominantly controlled by the liquid flow rate and secondarily by the applied voltage. It showed no dependence on capillary size. For a given liquid, stable and monodisperse electrosprays could be established only within certain ranges of liquid flow rates and applied voltages, that defined a cone-jet domain. This domain was affected by the electric conductivity of the liquid. As the liquid electric conductivity increased, the domain shifted toward smaller flow rates which implies that smaller droplets were generated in the spray. An increase in the capillary diameter caused a narrowing of this domain. Outside the cone-jet domain, electrosprays were unstable and polydisperse with different instability patterns that depended on the applied voltage and the liquid flow rate. Experiments also showed that the droplet size and the spray monodispersity were independent of the electrode configuration, as long as the electrospray was operated at the onset voltage condition, that is defined as the minimum voltage at which the cone-jet mode was established. By using dimensional analysis the controlling variables were combined into a few dimensionless groups and an empirical fit was derived and was shown to correlate well all the experimental data.

Stimulus-transcription coupling in pheochromocytoma cells. Promoter region-specific activation of chromogranin a biosynthesis

To explore stimulus-transcription coupling in pheochromocytoma cells, we studied the biosynthetic response of chromogranin A, the major soluble protein co-stored and co-released with catecholamines, to chromaffin cells' physiologic nicotinic cholinergic secretory stimulation. Chromogranin A mRNA showed a time-dependent 3.87-fold response to nicotinic stimulation, and a nuclear run-off experiment indicated that the response occurred at a transcriptional level. Transfected chromogranin A promoter/luciferase reporter constructs were activated by nicotinic stimulation, in time- and dose-dependent fashions, in both rat PC12 pheochromocytoma cells and bovine chromaffin cells. Cholinergic subtype agents indicated that nicotinic stimulation was required. Promoter deletions established both positive and negative nicotinic response domains. Transfer of candidate promoter domains to a heterologous (thymidine kinase) promoter conferred region-specific nicotinic responses onto that promoter. A proximal promoter domain (from -93 to -62 base pairs) was activated in copy number- and distance-dependent fashion, and thus displayed features of a promoter element. Its activation was sufficient to account for the overall positive response to nicotine. Within this proximal region, a cAMP response element (CRE) was implicated as a major nicotinic response element, since a CRE point-gap mutation decreased nicotinic induction, transfer of CRE to a thymidine kinase promoter augmented the promoter's response to nicotine, and nicotine activated the CRE-binding protein CREB through phosphorylation at serine 133. We conclude that secretory stimulation of pheochromocytoma cells also activates the biosynthesis of the major secreted protein (chromogranin A), that the activation is transcriptional, and that a small proximal domain, including the CRE box, is, at least in part, both necessary and sufficient to account for the positive response to nicotine.

Human prostate carcinoma cells express functional alphaIIb(beta)3 integrin

The integrin alphaIIb(beta)3 was initially believed to be expressed only in cells from the megakaryocytic lineage, such as platelets or HEL cells. In this study, we report for the first time that human prostate carcinoma PC-3 and DU-145 cells express alphaIIb(beta)3. Reverse transcription-PCR from HEL (positive control), PC-3, and DU-145 cells amplified a predicted alphaIIb fragment that hybridized to the full-length alphaIIb cDNA probe. DNA sequencing of the PCR fragments revealed 100% sequence homology to the corresponding extracellular domain of platelet alphaIIb but minimal sequence homology to integrins (alpha)v or a5. An RNase protection assay was used to confirm the results from reverse transcription-PCR. An antisense riboprobe to alphaIIb mRNA hybridized to total RNA from HEL, PC-3, and DU-145 cells, suggesting that alphaIIb mRNA is transcribed in these tumor cells. In situ hybridization on surgical specimens from human prostate tumor tissue stained positive with an antisense riboprobe to alphaIIb mRNA. The expression of alphaIIb(beta)3 protein in PC-3 and DU-145 cells was demonstrated by Western and dot blotting and flow cytometry with monoclonal antibodies (mAbs) to alphaIIb (MAB 1990), beta3, and alphaIIb(beta)3 (AP-2). A protein kinase C activator, phorbol 12-myristate 13-acetate, increased the adhesion of PC-3 cells to PAC-1, a mAb specific to the high-affinity state of alphaIIb(beta)3, by more than 80-fold. The invasion of DU-145 cells through a reconstituted basement membrane was blocked 40-50% by mAbs AP-2 or PAC-1. These data collectively suggest that: (a) prostate tumor cells express alphaIIb(beta)3; (b) surface expression of alphaIIb(beta)3 integrin is regulated by protein kinase C; and (c) mAbs to this receptor inhibit invasion of prostate cancer cells through a reconstituted basement membrane.

A strategy for rapid and efficient DNA sequencing by mass spectrometry

Two methods of solid-phase Sanger DNA sequencing followed by detection with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry are demonstrated. In one method, sequencing ladders generated on an immobilized synthetic template were resolved up to the 63-mer including the primer. Detection sensitivity and resolution were sufficient for sequence analysis in the given range. This approach is particularly suitable for comparative (diagnostic) DNA sequencing. A second method that has the potential for high throughput de novo DNA sequencing is also presented; it uses immobilized duplex probes with five-base single-stranded overhangs to capture an unknown DNA template serving as primers for Sanger DNA sequencing. The power of mass spectrometry is demonstrated not only by its very high speed, but also by its ability to identify sequences that are not readable using gel electrophoresis.

[Preliminary research on Bifidobacterium cuniculi in stomach and intestines of rabbits]

The distribution of Bifidobacterium in stomach and intestines of ten healthy rabbits were studied by microecological methods. The results showed that Bifidobacterium exist in stomach, small intestine and large intestine, the amount hightest in large intestine, second in jejunum and no finnd in duodenum. Being isolated, purified and biologically identified, the bacteria was identified as Bifidobacterium cuniculi, whose other biological characteristics also was studied.

Spatially selective photocoagulation of biological tissues: feasibility study utilizing cryogen spray cooling

Successful laser treatment of selected dermatoses such as hemangiomas requires thermally induced damage to blood vessels while protecting the epidermis. We present and test a procedure in a rabbit liver tissue model that utilizes cryogen spray cooling during continuous Nd:YAG laser irradiation to induce deep photocoagulation necrosis while protecting superficial tissues from thermal injury. Gross and histologic observations are consistent with calculated thicknesses of protected and photocoagulated tissues and demonstrate the feasibility of inducing spatially selective photocoagulation when cryogen spray cooling is used in conjunction with laser irradiation. This procedure may be useful in the thermal treatment of some pathological conditions for which it is desired that deep photocoagulation be induced while protecting superficial tissues.

High-resolution MALDI Fourier transform mass spectrometry of oligonucleotides

The matrix-assisted laser desorption/ionization (MALDI) method has been used with an external ion source Fourier transform mass spectrometer (FIMS) to analyze single-stranded, mixed-base oligomers of DNA. It is demonstrated that ultrahigh mass resolution (830 000 fwhm) can be achieved for small oligomers, and high resolution (136 000 fwhm) can be achieved for a 25-mer at m/z 7634. MALDI-FTMS can clearly separate the molecular ion peaks from analyte-matrix adduct peaks and alkali metal-containing species that result from replacement of hydrogen ions with sodium or potassium ions at multiple sites along the phosphate backbone. Previous MALDI-FTMS studies of oligonucleotides had two limitations: (1) low sensitivity due to difficulty in trapping the high kinetic energy ions made by the laser and (2) fragmentation of the ions due to the long delay (tens to hundreds of milliseconds) between their formation and detection. Both of these problems are alleviated in the present study. With the external ion source FTMS instrument, ions made by MALDI are injected at low energy into the analyzer cell by a rf-only quadrupole ion guide, captured by gating the voltage on the trapping plates, and cooled by a 0.5-s pulse of argon gas. Under these conditions, fragmentation is minimized, and DNA ions can be trapped in the FTMS analyzer cell for greater than 50 s. Sensitivity is also improved, as demonstrated by detection of 1 pmol of a single-stranded, mixed-base 20-mer of DNA, with a signal-to-noise ratio greater than 20:1.