Kinesin is a candidate for cross-bridging microtubules and intermediate filaments. Selective binding of kinesin to detyrosinated tubulin and vimentin

We showed previously that stable, detyrosinated (Glu) microtubules function to localize vimentin intermediate filaments in fibroblasts (Gurland, G., and Gundersen, G. G. (1995) J. Cell Biol. 131, 1275-1290). To identify candidate proteins that mediate the Glu microtubule-vimentin interaction, we incubated microtubules with microtubule-interacting proteins and saturating levels of antibodies to Glu or tyrosinated (Tyr) tubulin. Antibodies to Glu tubulin prevented the microtubule binding of kinesin obtained from fibroblast or brain extracts more effectively than antibodies to Tyr tubulin. Scatchard plot analysis showed that kinesin heads bound to Glu microtubules with an approximately 2.8-fold higher affinity than to Tyr microtubules. Purified brain kinesin cosedimented with vimentin, but not with neurofilaments, indicating that kinesin specifically associates with vimentin without accessory molecules. Kinesin binding to vimentin was not sensitive to ATP, and kinesin heads failed to bind to vimentin. By SDS-polyacrylamide gel electrophoresis, a kinesin heavy chain of approximately 120 kDa and a light chain of approximately 64 kDa were detected in vimentin/kinesin pellets. The light chain reacted with a general kinesin light chain antibody, but not with two other antibodies that recognize the two known isoforms of kinesin light chain in brain, suggesting that the kinesin involved in binding to vimentin may be a specific one. These results demonstrate a kinesin-based mechanism for the preferential interaction of vimentin with detyrosinated microtubules.

Kinesin- and myosin-driven steps of vesicle recruitment for Ca2+-regulated exocytosis

Kinesin and myosin have been proposed to transport intracellular organelles and vesicles to the cell periphery in several cell systems. However, there has been little direct observation of the role of these motor proteins in the delivery of vesicles during regulated exocytosis in intact cells. Using a confocal microscope, we triggered local bursts of Ca2+-regulated exocytosis by wounding the cell membrane and visualized the resulting individual exocytotic events in real time. Different temporal phases of the exocytosis burst were distinguished by their sensitivities to reagents targeting different motor proteins. The function blocking antikinesin antibody SUK4 as well as the stalk-tail fragment of kinesin heavy chain specifically inhibited a slow phase, while butanedione monoxime, a myosin ATPase inhibitor, inhibited both the slow and fast phases. The blockage of Ca2+/calmodulin-dependent protein kinase II with autoinhibitory peptide also inhibited the slow and fast phases, consistent with disruption of a myosin-actin- dependent step of vesicle recruitment. Membrane resealing after wounding was also inhibited by these reagents. Our direct observations provide evidence that in intact living cells, kinesin and myosin motors may mediate two sequential transport steps that recruit vesicles to the release sites of Ca2+-regulated exocytosis, although the identity of the responsible myosin isoform is not yet known. They also indicate the existence of three semistable vesicular pools along this regulated membrane trafficking pathway. In addition, our results provide in vivo evidence for the cargo-binding function of the kinesin heavy chain tail domain.

Human herpesvirus 8 LANA interacts with proteins of the mSin3 corepressor complex and negatively regulates Epstein-Barr virus gene expression in dually infected PEL cells

The human herpesvirus 8 (HHV-8) latency-associated nuclear antigen (LANA) is expressed in all latently HHV-8 infected cells and in HHV-8-associated tumors, including primary effusion lymphoma (PEL). To better understand the contribution of LANA to tumorigenesis and to the PEL phenotype, we performed a yeast two-hybrid screen which identified the corepressor protein SAP30 as a LANA binding protein. SAP30 is a constituent of a large multicomponent complex that brings histone deacetylases to the promoter. Glutathione S-transferase affinity assays confirmed interaction between LANA and SAP30 and also demonstrated interactions between LANA and two other members of the corepressor complex, mSin3A and CIR. The corepressors bound to the amino-terminal 340-amino-acid domain of LANA. In transient expression assays, this same domain of LANA mediated repression when targeted to a 5xGal4tk-CAT reporter as a GAL4-LANA fusion. PEL cells have the unusual feature that they are frequently dually infected with both HHV-8 and Epstein-Barr virus (EBV). We found that EBV EBNA-1 expression is downregulated in PEL cells at both the RNA and protein levels. In transient expression assays, LANA repressed activated expression from the EBV Qp and Cp latency promoters. Reduction of endogenous Qp activity could also be demonstrated in EBV-infected Rael cells transfected with a LANA expression plasmid. In contrast to the effect of LANA on EBV latency promoters, LANA activated expression from its own promoter. The data indicate that LANA can mediate transcriptional repression through recruitment of an mSin3 corepressor complex and further that LANA-mediated repression is likely to contribute to the low level of EBV latency gene expression seen in dually infected PEL cells.

Detyrosination of tubulin regulates the interaction of intermediate filaments with microtubules in vivo via a kinesin-dependent mechanism

Posttranslationally modified forms of tubulin accumulate in the subset of stabilized microtubules (MTs) in cells but are not themselves involved in generating MT stability. We showed previously that stabilized, detyrosinated (Glu) MTs function to localize vimentin intermediate filaments (IFs) in fibroblasts. To determine whether tubulin detyrosination or MT stability is the critical element in the preferential association of IFs with Glu MTs, we microinjected nonpolymerizable Glu tubulin into cells. If detyrosination is critical, then soluble Glu tubulin should be a competitive inhibitor of the IF-MT interaction. Before microinjection, Glu tubulin was rendered nonpolymerizable and nontyrosinatable by treatment with iodoacetamide (IAA). Microinjected IAA-Glu tubulin disrupted the interaction of IFs with MTs, as assayed by the collapse of IFs to a perinuclear location, and had no detectable effect on the array of Glu or tyrosinated MTs in cells. Conversely, neither IAA-tyrosinated tubulin nor untreated Glu tubulin, which assembled into MTs, caused collapse of IFs when microinjected. The epitope on Glu tubulin responsible for interfering with the Glu MT-IF interaction was mapped by microinjecting tubulin fragments of alpha-tubulin. The 14-kDa C-terminal fragment of Glu tubulin (alpha-C Glu) induced IF collapse, whereas the 36-kDa N-terminal fragment of alpha-tubulin did not alter the IF array. The epitope required more than the detyrosination site at the C terminus, because a short peptide (a 7-mer) mimicking the C terminus of Glu tubulin did not disrupt the IF distribution. We previously showed that kinesin may mediate the interaction of Glu MTs and IFs. In this study we found that kinesin binding to MTs in vitro was inhibited by the same reagents (i.e., IAA-Glu tubulin and alpha-C Glu) that disrupted the IF-Glu MT interaction in vivo. These results demonstrate for the first time that tubulin detyrosination functions as a signal for the recruitment of IFs to MTs via a mechanism that is likely to involve kinesin.

Low concentrations of nocodazole interfere with fibroblast locomotion without significantly affecting microtubule level: implications for the role of dynamic microtubules in cell locomotion

The role of microtubules (MTs) in cell locomotion is uncertain: while MTs are not essential for motility of certain cells, MTs are necessary for the directed translocation of large cells such as fibroblasts, endothelial cells and neuronal growth cones. Based on previous studies, we hypothesize that cell locomotion may involve MTs in two possible ways: (1) the rate of cell locomotion is proportional to MT level; or (2) cell locomotion is not proportional to MT level but requires a critical level of MTs to proceed. To test these hypotheses, we measured the rate of locomotion of NRK fibroblasts migrating into an in vitro wound, before and after treatment with different concentrations of nocodazole to generate cells with different levels of MTs. Locomotion of cells was monitored directly using timelapse recording and analyzed with an Image-1 image analysis program. Addition of nocodazole (> or = 50 nM) resulted in a rapid reduction in locomotion to a new rate that was maintained for > 2 hours. We found that addition of as little as 100 nM nocodazole decreased the rate of locomotion by more than 60%; and that 300 nM nocodazole completely stopped cell locomotion. Although 100 nM nocodazole decreased locomotion over 60%, we detected no qualitative change in MT distribution by immunofluorescence. Quantitative analysis of MT fluorescence in immunofluorescently stained preparations showed that 100 nM nocodazole had no detectable effect on MT levels and that 300 nM nocodazole only decreased MT levels to approximately 40% of controls. Quantitative analysis of tubulin polymer levels by cell extraction and western blotting yielded results similar to those obtained by quantification of MT fluorescence. A comparison of the locomotion rate measurements with the MT level measurements indicated that over half of the cell locomotion rate could be blocked by nocodazole without significantly affecting MT levels in the cell; the remaining locomotion rate was reduced proportionally to MT levels. These results do not support the notion that a critical level of MTs is required for cell locomotion and suggest that only a portion (< 50%) of the speed of the cells is proportional to MT levels. Rather, by analogy with studies of MT antagonists on the mitotic spindle, they suggest a third possibility: that low concentrations of nocodazole interfere with MT dynamics and thus, MT dynamics are critical for the maximal speed of cell locomotion. This notion was further supported by analogous effects of taxol and vinblastine on cell locomotion: at concentrations that reportedly cause little change in the level of MTs, taxol and vinblastine also dramatically decreased the rate of locomotion of NRK cells. In summary, our results establish the relationship between microtubule levels and locomotion rate and suggest that dynamic MTs are rate-limiting for fibroblast locomotion.

Observations on changes in ultrasonically treated waste-activated sludge

This work experimentally elucidates the effects of ultrasonic treatment on the physical, chemical, and biological characteristics of a waste-activated sludge. A critical ultrasonic power level exists above which, accompanied with the release of divalent cations from the sludge body, the floc structure effectively disintegrated, microbial level acceptably disinfected, and particulate organic compounds sufficiently transformed into soluble state. Both ultrasonic vibration and bulk temperature rise contribute to the treatment efficiency. Possible mechanisms of ultrasonic treatment are discussed.

Interaction with the Epstein-Barr virus helicase targets Zta to DNA replication compartments

Zta has a dual role in the Epstein-Barr virus (EBV) lytic cycle, acting as a key regulator of EBV lytic gene expression and also being essential for lytic viral DNA replication. Zta's replication function is mediated in part through interactions with the core viral replication proteins. We now show interaction between Zta and the helicase (BBLF4) and map the binding region to within amino acids (aa) 22 to 86 of the Zta activation domain. In immunofluorescence assays, green fluorescent protein (GFP)-tagged BBLF4 localized to the cytoplasm of transfected cells. Cotransfection of Zta resulted in translocation of BBLF4-GFP into the nucleus indicating interaction between these two proteins. However, Zta with a deletion of aa 24 to 86 was unable to mediate nuclear translocation of BBLF4-GFP. Results obtained with Zta variants carrying deletions across the aa 24 to 86 region indicated more than one contact site for BBLF4 within this domain, and this was reinforced by the behavior of the four-point mutant Zta (m22/26,74/75), which was severely impaired for BBLF4 interaction. Binding of BBLF4 to Zta was confirmed using GST affinity assays. In both cotransfection-replication assays and replication assays performed in EBV-positive P3HR1 cells, the Zta (m22/26,74/75) mutant was replication defective. In Zta-transfected D98-HR1 cells, replication compartments could be detected by immunofluorescence staining using anti-BMRF1 monoclonal antibody. Cells transfected with Zta variants that were defective for helicase binding still formed replication compartments, but Zta was excluded from these compartments. These experiments reveal a role for the Zta-helicase interaction in targeting Zta to sites of viral DNA replication.

Pneumatic lithotripsy versus laser lithotripsy in the endoscopic treatment of ureteral calculi

PURPOSE

To compare the efficacy, safety, and features of pneumatic lithotripsy (PL) with those of laser lithotripsy (LL) and present our clinical experience in the endoscopic management of ureteral calculi.

PATIENTS AND METHODS

From August 1994 to February 2000, 285 consecutive patients underwent endoscopic lithotripsy with either the Swiss Lithoclast pneumatic lithotripter (145 patients) or the Ho:YAG laser lithotripter (140 patients) for the treatment of ureteral calculi.

RESULTS

In one single session, the overall successful stone fragmentation rate of LL was higher than that of PL (95.7% v 69.7%; P < 0.01). The average time to stone-free status was shorter for LL than for PL (18 days v 31 days; P < 0.01). No major complications were observed in LL, while five ureteral perforations were encountered in PL.

CONCLUSIONS

Laser lithotripsy has advantages over PL in high efficiency of stone fragmentation and a low complication rate. Laser lithotripsy is a powerful, effective, and safe treatment modality for ureteral calculi.

A quantitative evaluation of peroxidase inhibitors for tyramide signal amplification mediated cytochemistry and histochemistry

Many peroxidase inhibitors have been used in horseradish peroxidase (HRP) mediated immunostaining and in situ hybridization to quench background peroxidase activity. However, the efficacy of these inhibitors has been controversial, partially due to the lack of a quantitative study. Tyramide signal amplification (TSA) is much more sensitive than other HRP-mediated methods but its super-sensitivity also demands effective inhibition of background peroxidase activity. In searching for an effective peroxidase inhibitor, we have systematically evaluated the efficacy of several peroxidase inhibitors by quantifying the fluorescence intensity in cultured fibroblasts and tissue sections treated with the inhibitors. For cultured cells, 0.05 mM of phenylhydrazine and 1 unit/ml of glucose oxidase gave only moderate inhibition of HRP activity while 1 mM of sodium azide (NaN(3)), 3% of hydrogen peroxide (H(2)O(2)), NaN(3)/H(2)O(2) combined and 0.02 N hydrochloric acid (HCl) provided more complete inhibition. However, the inhibitory effect of NaN(3)/H(2)O(2) is reversible upon removal of the inhibitors and followed by incubation and wash to mimic antibody interactions. Similar results were obtained from rat skin wound tissues that have strong endogenous peroxidase activity. Our results recommend the use of HCl and caution the use of phenylhydrazine, glucose oxidase, NaN(3) and H(2)O(2) as potent peroxidase inhibitors.

Enteral versus parenteral nutrition in critically ill patients with severe pancreatitis: a meta-analysis

Whether enteral nutrition (EN) is superior to parenteral nutrition (PN) in critically ill patients with severe acute pancreatitis remains unknown. The objective of this meta-analysis was to assess the effects of EN versus PN on clinical outcomes in a subgroup of pancreatitis patients. Relevant randomized controlled trials (RCTs) were searched in Scopus, PubMed and Web of Science from inception to August 2016. Ultimately, five RCTs including 348 patients were enrolled in this analysis. Compared with PN, EN was associated with a significant reduction in overall mortality (risk ratio (RR)=0.36, 95% confidence interval (CI) 0.20-0.65, P=0.001) and the rate of multiple organ failure (RR=0.39, 95% CI 0.21-0.73, P=0.003). EN should be recommended as the preferred route of nutrition for critically ill patients with severe acute pancreatitis.

wblA, a pleiotropic regulatory gene modulating morphogenesis and daptomycin production in Streptomyces roseosporus

AIMS

The wblA gene, encoding a homologue of the WhiB family protein, was identified in the sequenced genome of daptomycin producer Streptomyces roseosporus. To explore the function of wblA, we construct wblA disruption strains, complemented strains and overexpression strains to test whether it can affect the production of secondary metabolites and morphogenesis.

METHODS AND RESULTS

We constructed disruption strains by homologous recombination in S. roseosporus. The disruption mutant of wblA could block aerial mycelium sporulation and enhance the production of daptomycin by 51%. In contrast, overexpression of wblA resulted in significantly decreased the yield of daptomycin. In agreement with it, the transcription of key daptomycin regulatory genes atrA, dptR2 and dptR3 and structural gene dptE remarkably increased in the wblA disruption mutant.

CONCLUSIONS

wblA plays a key role in control of daptomycin biosynthesis and is essential for sporulation. The disruption of wblA could accumulate the transcription level of some key genes involving in daptomycin biosynthesis.

SIGNIFICANCE AND IMPACT OF THE STUDY

Daptomycin is an important antibiotic with potent activity against a variety of Gram-positive pathogens. This study demonstrates that valuable improvement in the yield of daptomycin can be achieved through modulating the expression of wblA transcription regulator.

Improvement of A21978C production in Streptomyces roseosporus by reporter-guided rpsL mutation selection

AIMS

Daptomycin, one of the A21978C factors produced by Streptomyces roseosporus, is an acidic cyclic lipopeptide antibiotic with potent activity against a variety of Gram-positive pathogens. To increase the titre of this extensively used and clinically important antibiotic, we applied a reported-guided rpsL mutation selection system to generate strains producing high levels of A21978C.

METHODS AND RESULTS

In the reporter design, dptE was chosen as the overexpressing target, and neo-encoding neomycin phosphotransferase as the reporter. Using this reporter-guided selection system, 20% of the selected, streptomycin-resistant mutants produced greater amounts of A21978C than the starting strain. The selection system increased the screening efficiency about 10-fold with a frequency of 1·7% A21978C overproducing strains among str(r) mutants. A21978C production was increased approximately 2·2-fold in the rpsL K43N mutant.

CONCLUSIONS

The combination of ribosome engineering and reporter-guided mutant selection generated an A21978C overproducing strain that produced about twice as much A21978C as the parental strain.

SIGNIFICANCE AND IMPACT OF THE STUDY

The strategies presented here, which integrated the advantages of both ribosome engineering and reporter-guided mutation selection, could be applied to other bacteria to improve their yield of secondary metabolites.

Properties of two EBV Mta nuclear export signal sequences

The Epstein-Barr virus (EBV) Mta protein is a posttranscriptional regulator of EBV lytic gene expression that affects RNA splicing and transport. Mta mediates cytoplasmic accumulation of unspliced EBV replication gene transcripts and shuttles between the nucleus and cytoplasm. Mta contains a recognized leucine-rich, putative nuclear export signal (NES) between aa 227 and 236. Deletion of this signal sequence eliminated shuttling, while mutation of the core LXL motif in the putative NES diminished but did not abolish the ability of Mta to shuttle from donor to recipient cells in a heterokaryon assay. A double mutation of the LXL motif plus an upstream VTL motif eliminated shuttling, suggesting that Mta may have two NES motifs. In confirmation of this, transfer of either the sequence encoding the leucine-rich aa 227-236 motif or that encoding the adjacent hydrophobic aa 218-227 sequence to a GFP-NLS-pyruvate kinase reporter protein conferred the property of cytoplasmic accumulation onto the heterologous protein. Cytoplasmic accumulation of both the aa 225-237 and 218-227 containing reporters was minimal in the presence of the inhibitor leptomycin B, indicating that both motifs mediated Crm-1-dependent export. Mutations in the NES signal sequences abolished the ability of Mta to mediate cytoplasmic accumulation of BALF2 replication gene transcripts. This included mutation of the LXL motif which still showed cytoplasmic shuttling, suggesting that the NES mutations might have additional effects on Mta function. Wild-type Mta co-immunoprecipitated with the splicing factor SC35 and colocalized with SC35 in transfected cells, modifying endogenous SC35 distribution within the nucleus to give more intense, rounded spots. Interestingly, the NES mutant proteins appeared to have altered interactions with the splicing complex, binding more tightly to SC35 in co-immunoprecipitation assays. These observations suggest a linkage between the splicing and export functions of Mta.

Prevalence, concentrations, and antibiotic sensitivities of Salmonella serovars in poultry from retail establishments in Seattle, Washington

Poultry have been identified as one of the major sources of salmonellosis, with estimates ranging from 10 to 22% of total cases. Despite several advances in the industry and new performance standards, the incidence of salmonellosis in the population has not declined over the last 15 years. Salmonella is pervasive in a wide variety of foods, and thus, estimating its burden resulting from specific food categories has been challenging and plagued with uncertainty due to critical data gaps. The objective of this study was to conduct a year-long market survey (1,322 samples) to help bridge the data gaps on the contamination rates and levels of Salmonella on raw poultry by product type (i.e., breast, thighs, drums, wings, and split breast) and production method (conventional versus organic). The isolates recovered were serotyped and tested for antibiotic sensitivities. A PCR method was utilized for initial screening of samples after an overnight enrichment in tryptic soy broth. Three-tube most-probable-number (MPN) assays and anti-Salmonella immunomagnetic separation methods were utilized to determine the levels of Salmonella and aid with the recovery of Salmonella species, respectively. Eleven percent of the samples were positive for Salmonella. Significant differences in percent positive rates by product type included up to a 4-fold difference in percent positive rates between establishments, ranging from 7 to 31%. Of the samples positive for Salmonella species, 94% had <30 MPN/100 g. Production methods identified as organic or as not using antibiotics had significantly higher rates of recovery of Salmonella. On the other hand, all of the Salmonella isolates that were resistant to two or more antibiotics originated from conventional processing establishments where antibiotics were utilized. In addition, a significant proportion of isolates from conventionally processed products were serotypes clinically relevant to humans.

Radiofrequency ablation after transarterial embolization as therapy for patients with unresectable hepatocellular carcinoma

PURPOSE

To evaluate the usefulness of transcatheter arterial embolization (TAE) followed by radiofrequency ablation (RFA) as combined treatment for unresectable hepatocellular carcinoma (HCC).

PATIENTS AND METHODS

Thirty-six consecutive patients (cirrhosis, Child-Pugh class A or B) with solitary or oligonodular HCC were treated (41 lesions; mean size, 58.9 mm; range, 30-120 mm). RFA was performed after one TAE treatment. Local efficacy was evaluated with multiphasic computed tomography (CT) performed an average of two months after RFA and once during later follow-up.

RESULTS

The mean follow-up period was 16 months (range, 2-45 months). Technical success (namely, complete tumor devascularization during the arterial phase) was achieved for 59% of lesions at the first CT evaluation and for 46% at the second evaluation. Among prognostic factors included in the analysis, only lesion diameter (< 50 mm versus > or = 50 mm) was statistically significant in terms of predicting local success (Fisher's exact test: 85% versus 43% at first CT, p<0.01; 70% versus 36% during follow-up, p=0.05). There were no major periprocedural complications. Kaplan-Meier analysis showed survival rates of 84% at 12 months and 57% at 24 months.

CONCLUSIONS

Combined therapy--TAE then RFA--for unresectable HCC lesions in patients with cirrhosis produces a relatively high complete local response rate compared with TAE or RFA alone. Our results, considered with those from other case series, may help design prospective, randomized clinical trials to test combination therapy versus single-modality therapy in terms of risks and benefits.

Ion channels involved in the presynaptic hyperexcitability induced by herpes virus suis in rat superior cervical ganglion

Rat superior cervical ganglia infected with herpes virus suis (pseudorabies virus) display a spontaneous bursting activity of still unknown origin. Previous intracellular recordings from the ganglionic neurons combined with pharmacological studies showed that the postganglionic action potentials are induced by acetylcholine release spontaneously from the preganglionic nerve. In this study we investigated whether the acetylcholine release is caused by mechanisms which are dependent on action potentials spontaneously generated on the preganglionic nerve or by mechanisms which occur without any changes in the excitability of presynaptic fibers. Simultaneous intra- and extracellular recordings from the ganglion cells and from the preganglionic nerve, respectively, were performed 32-38 h after the inoculation of herpes virus suis (strain Aujeszky) into the anterior chamber of one eye of the rat. Tetrodotoxin, well known to prevent the generation of action potentials by blocking the fast sodium channels, completely and reversibly abolished, whereas the potassium channel blockers 4-aminopyridine and apamin, enhanced the spontaneous, bursting activity at pre- and postsynaptic levels. The nicotinic receptor antagonist hexamethonium abolished the postsynaptic discharges and reduced the preganglionic activity by 50%. Pre- and postsynaptic electrical activities were suppressed in low calcium Krebs' solution, demonstrating that extracellular calcium is required not only for acetylcholine release but also for triggering the presynaptic action potentials. It is concluded that in the infected ganglia the spontaneous acetylcholine release is due to the generation of action potentials in the preganglionic nerve. Voltage-gated sodium and calcium channels contribute to the presynaptic electrogenesis, while the latter appears to be damped by the activation of voltage- and calcium-dependent potassium channels. Possible factors as well as mechanisms inducing such an increase in excitability are discussed.

Breast cancer resistance protein-mediated topotecan resistance in ovarian cancer cells

Overexpression of breast cancer resistance protein (BCRP) and mitoxantrone (MX) resistance protein can confer resistance to a variety of cytostatic drugs, such as MX, topotecan (TPT), doxorubicin, and daunorubicin. This study investigates the role of BCRP in resistance of ovarian cancer to TPT treatment. We have developed TPT-resistant human ovarian cancer cell line. Intracellular concentration of fluorescent dye rhodamine 123 (Rh123) was measured by flow cytometry. The expression of several membrane transporter proteins including P-glycoprotein (P-gp), multidrug resistance protein 1 (MRP1), and BCRP were determined by reverse transcription-polymerase chain reaction and Western blotting. The Rh123 concentration in parental cells was approximately three times of those in TPT-resistant cells. In contrast to undetectable level of P-gp messenger RNA (mRNA) and minimal level of MRP1 expression in TPT-resistant cells, overexpression of both the BCRP mRNA and the protein was detected in these cells. Introduction of antisense-phosphorothioate oligonucleotide derived from BCRP mRNA into TPT-resistant cells resulted in a significant increase in the concentration of intracellular Rh123. These results suggested a novel mechanism in which a reduced intracellular drug concentration may be mediated by BCRP gene products in human ovarian cancer cells.

Relationship between 24-H blood pressure and sleep disordered breathing in a normotensive community sample

Sleep disordered breathing (SDB) and hypertension are commonly associated. In this study, we assessed how longitudinal measures of SDB predict a 24-h ambulatory blood pressure monitoring (ABPM) profile. Participants (n = 82) were recruited from a community-based urban (26% African American) sample and included family members of patients with laboratory diagnosed SDB (cases) and family members of neighborhood control subjects evaluated at baseline and at 5 years. Nearly all participants were normotensive and were not receiving therapy for SDB. During both examinations, the respiratory distress index (RDI) was assessed with overnight in-home polysomnography. Seated blood pressure (BP) was assessed at a baseline examination (t,) and after a 5-year follow-up period (t5), when 24-h ABPM also was performed. The change in RDI (t5-t1) over 5 years was significantly associated with 24-h mean systolic blood pressure (SBP) (P = .04), 24-h maximum diastolic blood pressure (DBP) (P = .03), sleep mean SBP (P = .05), sleep mean DBP (P < .05), and sleep maximum SBP (P = .02). Regression analysis revealed that average 24-h mean arterial pressure (MAP) and mean 24-h DBP were each best predicted by change in RDI, explaining 5% of the variance in these 24-h BP readings, and by current smoking status. After accounting for these variables, BP was not predicted by any of the other potential confounders (all P > .10). Mean RDI (averaged between t5 and t1) was associated with mean MAP, mean SBP, and maximal SBP measured during sleep. This study documents for the first time the association between changes in sleep apnea activity and BP and in a community-based normotensive sample. Further long-term evaluation of the effects of these findings and the long-term consequences of hypertension are needed.

Temporal down-regulation of Fc gamma RIII expression and Fc gamma receptor-mediated phagocytosis in human monocyte-derived macrophages induced by TNF-alpha and IL-1 beta

Effects of tumor necrosis factor (TNF-alpha) and interleukin-1 beta (IL-1 beta) on the expression of Fc gamma receptors (Fc gamma Rs) and on Fc gamma R-mediated phagocytosis in human monocyte-derived macrophages (MDMs) have been determined. Treatment of MDMs with TNF-alpha (400 pg/ml) or IL-1 beta (400 pg/ml) for 80 min decreased cell surface Fc gamma RIII expression, as measured by flow cytometry (FACS), while the levels of surface Fc gamma RI and Fc gamma RII remained unchanged. Surface Fc gamma RIII expression remained depressed for 7 h after exposure of MDMs to either cytokine but then rose progressively until, by 24 h of stimulation, the levels were at least as high as those on unstimulated cells. In parallel with cell surface Fc gamma RIII levels, phagocytosis of immunoglobulin G-opsonized fluorescent beads, as measured by FACS, decreased and then increased over time after stimulation of MDMs with TNF-alpha while the opsonin-independent phagocytic activity was unchanged, suggesting that among the three classes of Fc gamma receptors on macrophages, Fc gamma RIII may play a critical role in regulating opsonic phagocytosis. After treatment with IL-1 beta, both opsonic and nonopsonic phagocytic activities of MDMs were significantly decreased, regardless of Fc gamma RIII levels. FACS analysis of rhodamine-phalloidin-stained MDMs showed that after incubation with IL-1 beta, but not TNF-alpha, the content of F-actin declined in MDMs, coinciding with inhibition of particle phagocytosis. Rapid down-regulation and subsequent recovery of macrophage Fc gamma RIII expression following cytokine stimulation could serve as a novel regulatory mechanism employed by inflammatory cells in host defense.

Cloned primed lymphocyte test cells recognize the fourth, fifth, and sixth hypervariable regions at amino acid positions 65-87 of the DPB1 molecule

Genetic polymorphisms of the HLA-DPB1 gene in Japanese and Caucasian panel cells defined by PLT were analyzed by the PCR-based genotyping technique PCR-RFLP, and suballeles of DPw3 (DPB1*03) and DP"Cp63" (DPB1*09) could be detected. PLT-defined DPw3 cells were typed by PCR-RFLP as either DPB1*0301 or DPB1*1401. On the other hand, PLT-defined DPCp63-typed cells were typed as DPB1*0901 or DPB1*1001. These results indicate that both DPw3 and DPCp63 are split into two subantigens. DPw2 and DPw4 are DPB1*0201 and 0202 and DPB1*0401 and 0402, respectively. Comparative analysis of the amino acid sequences of the DPw2-, DPw4-, DPw3-, and DPCp63-associated alleles revealed that the fourth (C), fifth (D), and sixth (E) hypervariable regions at amino acid positions 65-87 were shared within the same PLT-defined DP antigen groups, suggesting that these three hypervariable regions are recognized by cloned T cells in PLT, thus determining DP antigen specificity. On the basis of this model, 44 DPB1 alleles can be classified into 18 antigen groups, each of which may possibly represent a PLT-defined single DP specificity.

Characterization of bacteriophage HN48 and its protective effects in Nile tilapia Oreochromis niloticus against Streptococcus agalactiae infections

Streptococcus agalactiae is a causative agent responsible for massive mortalities of tilapia that has led to catastrophic losses to tilapia culture globally. Bacteriophages represent a new class of antimicrobials against bacteria. In this study, we characterized the bacteriophage HN48, which formed small and round-transparent plaques on a double-layer plate. With a hexagonal head and a long tail, this phage may belong to the Caudovirales according to the International Committee on Taxonomy of Viruses. HN48 was found to have a relatively wide and highly specific host range, to be sensitive to high temperature (60-80°C) and low pH (3-5), and to be relatively stable at alkaline pH (8-10). Intraperitoneal injection with HN48 had no adverse effects on tilapia and effectively inactivated the bacteria in the kidney. Fish that received phage therapy had 60% ± 3.3% survival rates and a delayed mean death time of about 3 days when compared to the control group. To the best of knowledge, this is the first study of tilapia streptococcal phage. Overall, the results indicated that phage HN48 could prevent tilapia from experimental S. agalactiae infection, suggesting it has the potential to control this disease.

Small-angle x-ray scattering study of kinetics of spinodal decomposition in N-isopropylacrylamide gels

We present synchrotron-based time-resolved small-angle x-ray scattering (SAXS) measurements of spinodal decomposition in a covalently cross-linked N-isopropylacrylamide gel. The range of wave numbers examined is well beyond the position of the maximum in the structure factor S(q,t). The equilibrium structure factor is described by the sum of a Lorentzian and a Gaussian. Following a temperature jump into the two phase region, the scattered intensity increases with time and eventually saturates. For early times the linear Cahn-Hilliard-Cook (CHC) theory can be used to describe the time evolution of the scattered intensity. From this analysis we found that the growth rate R(q) is linearly dependent on q(2), in agreement with mean-field theoretical predictions. However the Onsager transport coefficient Lambda(q) approximately q(-4), which is stronger than the q dependence predicted by the mean-field theory. We found that the growth rate R(q)>0, even though the wave numbers q probed by SAXS are greater than sqrt[2]q(m) where q(m) is the position of the peak of S(q,t), also in agreement with the mean-field predictions for a deep quench. We have also examined the range of validity of the linear CHC theory, and found that its breakdown occurs earlier at higher wave numbers. At later times, a pinning of the structure was observed. The relaxation to a final, microphase-separated morphology is faster and occurs earlier at the highest wave numbers, which probe length scales comparable to the average distance between crosslinks.

Association of the 54-nucleotide repeat polymorphism of hPer3 with heroin dependence in Han Chinese population

Circadian clock genes have the function of producing circadian rhythm. They are also implicated in the origin or development of many diseases such as cancers and neuropsychiatric diseases. The purpose of this study is to determine whether the 54-nucleotide repeat polymorphism of hPer3, one of the circadian clock genes, associates with heroin dependence. DNA samples were obtained from 209 Chinese heroin-dependent subjects and 249 Chinese healthy controls. The 54-nucleotide repeat polymorphism was detected by polymerase chain reaction and DNA agarose gel electrophoresis. The frequency of four-repeat allele was significantly higher (chi(2)= 10.64, P = 0.001; corrected for multiple tests, P = 0.003) in the mixed gender heroin-dependent subject group (four repeat: 0.89, five repeat: 0.11) than in the mixed gender control group (four repeat: 0.81, five repeat: 0.19); the frequency of four-repeat allele was also significantly higher (chi(2)= 10.00, P = 0.002; corrected for multiple tests, P = 0.006) in the male heroin-dependent subject group (four repeat: 0.89, five repeat: 0.11) than in the male control group (four repeat: 0.81, five repeat: 0.19); for females, no significant trend was observed with the 54-nucleotide repeat polymorphism between the heroin-dependent subject group and the control group. Our results suggest that the 54-nucleotide repeat polymorphism of hPer3 significantly associates with heroin dependence at the allele frequency level and may be a potential risk factor for the development of heroin dependence.