Randomized controlled comparative clinical pharmacokinetic study of nab-paclitaxel and solvent-based paclitaxel in Chinese patients (pts) with metastatic breast cancer (MBC)

11505

Background: nab-paclitaxel is a novel solvent-free, 130-nM albumin-bound (nab™) formulation of paclitaxel. In previous studies, nab-paclitaxel demonstrated higher volume of distribution and clearance than that of paclitaxel formulated with Cremophor (Cr-PAC) in Caucasian patients (Sparreboom, Clin Cancer Res 2005;11:4136) and had greater response rate and favorable safety profile in pts with MBC (Gradishar et al., JCO, 2005;23:7794) . The aim of this study was to evaluate nab-paclitaxel blood pharmacokinetics (PK) and compare it with that of Cr-PAC in Chinese MBC patients.Methods: In this randomized controlled, open-label study, patients were assigned to either nab-paclitaxel 260 mg/m2 intravenously (iv) over 30 minutes q3w or Cr-PAC 175 mg/m2 iv over 3 hours q3w. At cycle 1, 12 patients in each treatment group participated in the PK study and then continued treatment until PD or unacceptable toxicity. Plasma samples from pts were analyzed for PK parameters. The primary clinical endpoints were ORR and toxicity (Guan et al; submitted, ASCO, 2007). Results: 24 female pts (median age 44.5 years) participated. No statistically significant between group differences were noted in age, height, weight, or baseline liver function. Paclitaxel blood PK parameters in 2 treatment groups are summarized in the Table. ORR: nab-paclitaxel, 75%; Cr-PAC, 25% (P = 0.018). The maximum grade (G) of neutropenia and neuropathy in the nab-paclitaxel and Cr-PAC groups were G3 and G2, respectively, with no significant between-group difference. Conclusion: nab-Paclitaxel had a greater distribution volume, clearance, and smaller dose adjusted AUC0-inf compared with that of Cr-PAC. There was no significant difference in T1/2 in the 2 groups. PK results in Chinese pts are identical to data reported in Caucasian pts. The lower CL and Vz for Cr-PAC are probably related to sequestration of paclitaxel in the blood by Cremophor. * dose adjusted AUC0-inf

[Table: see text]

[Table: see text]

Randomized study comparing nab-paclitaxel with solvent-based paclitaxel in Chinese patients (pts) with metastatic breast cancer (MBC)

1038

Background: The results of a large clinical study comparing solvent-based paclitaxel 175 mg/m2 with 130-nM albumin-bound paclitaxel (nab-paclitaxel) 260 mg/m2 demonstrated that nab-paclitaxel had greater efficacy and a favorable safety profile in pts with MBC (Gradishar et al., JCO, 2005; 23:7794). The maximum tolerated dose of nab-paclitaxel was 300 mg/m2 infused over 30 minutes without premedication in Chinese pts with solid tumors (Teng et al., Ai Zheng, 2004;23:1431). The aim of this randomized study is to compare the response rates and to evaluate the safety of nab-paclitaxel with those of solvent-based paclitaxel in Chinese pts with MBC. Methods: In this open-label, multicenter study, 210 pts with MBC were assigned to either solvent-based paclitaxel 175 mg/m2 intravenously (IV) over 3 hours every 3 weeks (q3w) with standard premedication (steroids and antihistamines) or nab-paclitaxel 260 mg/m2 IV over 30 minutes q3w with no premedication for 1–6 cycles. The primary endpoints were the overall response rate (ORR, complete or partial response) and toxicity. Stable disease (SD) at =16 weeks was measured. All pts who received at least 1 dose of study drug were evaluable for study endpoints. Results: 210 pts (median age, 50 years; 70% postmenopausal) were enrolled from 29 June 2005 - 1 August 2006. Efficacy results are summarized in the Table . The common toxicities occurring at =20% were alopecia (78%), peripheral neuropathy (75%, 7% gr 3), neutropenia (65%), leucopenia (60%), myalgia (39%), arthralgia (23%), and nausea (21%) and were similar between groups (P = NS). Gr 3/4 neutropenia, measured on days 1 and 8, were similar between groups (p = 0.202). Conclusions: Compared to solvent- based paclitaxel, treatment with nab-paclitaxel was associated with a higher response rate and longer time to progression without increased toxicity. These comparative data in Chinese pts are almost identical to results previously reported in Caucasian pts (Gradishar et al, JCO, 2005).

[Table: see text]

[Table: see text]

Automated sample preparation and purification of homogenized brain tissues

A robotic homogenized tissue sample transferring method has been developed by using a Packard MultiProbe II 8-tip system. It enables robotically transferring homogenized tissue samples from individual test tubes into a 96-well format plate for further sample purification and analysis. Extensive validation has been made to establish the accuracy and variability of this method. This automatic tissue sample transferring approach combined with automatic tissue homogenization, has significantly increased the throughput of tissue sample preparation in screening of drug candidates using liquid chromatography coupled with highly sensitive and selective tandem mass spectrometry (LC-MS/MS).

Analysis of alpha-fetoprotein mRNA level on the tumor cell hematogenous spread of patients with hepatocellular carcinoma undergoing orthotopic liver transplantation

The aim of this study was to detect alpha-fetoprotein (AFP) mRNA levels in the preoperative and intraoperative peripheral blood of patients with hepatocellular carcinoma (HCC) receiving orthotopic liver transplantation (OLT).

METHODS

We detected AFP mRNA by TaqMan real-time reverse transcriptase-polymerase chain reactions (RT-PCR) on the peripheral blood cells (PBCs) from 30 HCC patients undergoing OLT.

RESULTS

In RT-PCR, fluorescence was undetectable in any control. The positive expression rate of AFP mRNA was 23% (7 of 30) in PBC samples of OLT patients preoperatively and 50% (15 of 30) just before hepatectomy during the operation. The positive rate of AFP mRNA in OLT patients at this time was higher than that at preoperation, a difference that was statistically significant (P < .01).

CONCLUSION

The OLT operation induced release of cells from the liver into the peripheral blood circulation. This may be an important mechanism of liver cancer cell dissemination deserving further investigation.

Two eudesmane sesquiterpenes from Laggera pterodonta

Two new eudesmane sesquiterpenes, 2alpha-hydroxy pterodontic acid (1) and pterodolide [3alpha-(2-methyl-2,3-epoxy)-butyric-4alpha-acetoxy-8beta-ethoxy eudesma-7(11)-en-8alpha,12-olide (2), along with five known compounds (3-7) were isolated from the aerial parts of Laggera pterodonta. Their structures were elucidated on the basis of spectroscopic methods. The immunosuppressive activity of the isolated compounds was investigated.

The Expression of von Willebrand Factor, Soluble Thrombomodulin, and Soluble P-Selectin During Orthotopic Liver Transplantation

BACKGROUND

We evaluated von Willebrand factor (vWF), soluble thrombomodulin (sTM), and soluble P-selectin (sP-selectin) levels in ischemia/reperfusion injury during orthotopic liver transplantation (OLT).

METHODS

The vWF, sTM, and sP-selectin were analyzed in 20 patients who underwent liver transplantation. Blood samples were drawn from the radial artery at serial times during surgery. Plasma levels of sTM and sP-selectin were detected by enzyme-linked immunosorbent assay (ELISA). The wWF activity was measured using the immuno-turbidimetric method. Plasma aspartate transaminase (AST) and alanine transaminase (ALT) were assayed by routine clinical chemistry testing.

RESULTS

Marked elevation levels of plasma AST and ALT were released during the 15 minutes after reperfusion phase, with a peak on the first postoperative day (P < .01). The sTM level remained unchanged from preoperative to anhepatic phase (P > .05). In contrast, a mean 2.5-fold increase of sTM was observed during the 15-minute reperfusion stage compared with the preoperative value (P < .01). The vWF activity only showed significant increase during the 60-minute reperfusion stage compared with the preoperative value (P < .05). No significant increase occurred in sP-seletin levels during the reperfusion phase. Platelet count showed significant decrease during the entire observation period compared with the preoperative value (P < .01).

CONCLUSION

The endothelial reperfusion injury after OLT is characterized by increased vWF and sTM but not by sP-selectin in peripheral blood.

Evidence for a distinct group of nestin-immunoreactive neurons within the basal forebrain of adult rats

Nestin is an intermediate filament protein serving as a marker for neuroprogenitor and stem cells. Here we report that a cluster of previously unrecognized nestin immunoreactive (nestin-ir) neurons was located in the medial septum-diagonal band of Broca (MS-DBB) of the basal forebrain in adult rats. Nestin-ir neurons were exclusively located in the MS-DBB and intermingled with choline acetyltransferase-ir (ChAT-ir), parvalbumin-ir (PV-ir), or nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase reactive (NADPHd-reactive) neurons. However, there was no colocalization between nestin-ir and PV-ir in single neurons in MS-DBB; only about 35% of nestin-ir neurons were ChAT-ir, and 8%-12% of nestin-ir neurons were NADPHd-reactive. Morphologically, nestin-ir neurons showed a larger size of somata than that of ChAT-ir or PV-ir neurons and the distribution of nestin-ir neurons spread across the rostro-caudal extent of the MS-DBB. Moreover, retrograde tracing revealed that a significant portion of these nestin-ir neurons projected to the thalamus and hippocampus. These results, for the first time, provide strong evidence that there exists a cluster of previously unrecognized nestin-ir neurons in MS-DBB of the basal forebrain in adult rats and that these nestin-ir neurons are distinguishable from ChAT-ir, PV-ir, and NADPHd-reactive neurons.

Dendritic plasticity of CA1 pyramidal neurons after transient global ischemia

Dendrites and spines undergo dynamic changes in physiological conditions, such as learning and memory, and in pathological conditions, such as Alzheimer's disease and epilepsy. Long-term dendritic plasticity has also been reported after ischemia/hypoxia, which might be compensatory effects of surviving neurons for the functional recovery after the insults. However, the dendritic changes shortly after ischemia, which might be associated with the pathogenesis of ischemic cell death, remain largely unknown. To reveal the morphological changes of ischemia-vulnerable neurons after ischemia, the present study investigated the alteration of dendritic arborization of CA1 pyramidal neurons in rats after transient cerebral ischemia using intracellular staining technique in vivo. The general appearance of dendritic arborization of CA1 neurons within 48 h after ischemia was similar to that of control neurons. However, a dramatic increase of dendritic disorientation was observed after ischemia with many basal dendrites coursed into the territory of apical dendrites and apical dendrites branched into the region of basal dendrites. In addition, a significant increase of apical dendritic length was found 24 h after ischemia. The increase of dendritic length after ischemia was mainly due to the dendritic sprouting rather than the extension of individual dendrites, which mainly occurred in the middle segment of the apical dendrites. These results reveal a plasticity change in dendritic arborization of CA1 neurons shortly after cerebral ischemia.

Tumor necrosis factor prevents alendronate-induced osteoclast apoptosis in vivo by stimulating Bcl-xL expression through Ets-2

OBJECTIVE

To investigate why bisphosphonates are less effective at preventing focal bone loss in rheumatoid arthritis (RA) patients than in those with generalized osteoporosis, and the mechanisms involved.

METHODS

The response of osteoclasts to alendronate (ALN) in tumor necrosis factor-transgenic (TNF-Tg) mice that develop erosive arthritis and in wild-type littermates was studied. TNF-Tg and wild-type mice were given ALN, and the osteoclast numbers in the inflamed joints and in the long bones were compared. The expression levels of Bcl-xL in the osteoclasts of TNF-Tg and wild-type mice were examined by immunostaining. The effect of overexpression of Bcl-xL and Ets-2 proteins on ALN-induced osteoclast apoptosis was determined using an in vitro osteoclast survival assay and retrovirus transfer approach.

RESULTS

ALN reduced osteoclast numbers in the metaphyses by 97%, but by only 46% in the adjacent inflamed joints. Bcl-xL expression was markedly higher in osteoclasts in the joints than in those in the metaphyses of TNF-Tg mice. Bcl-xL or Ets-2 overexpression protected osteoclasts from ALN-induced apoptosis, and TNF stimulated Bcl-xL and Ets-2 expression in osteoclasts. Overexpression of Ets-2 increased Bcl-xL messenger RNA in osteoclasts, while a dominant-negative form of the Ets-2 blocked the protective effect of Bcl-xL or TNF on ALN-induced apoptosis.

CONCLUSION

The reduced efficacy of bisphosphonates to stop bone erosion in the inflamed joints of RA patients may result from local high levels of TNF up-regulating Ets-2 expression in osteoclasts, which in turn stimulates Bcl-xL expression in them and reduces their susceptibility to bisphosphonate-induced apoptosis.

Validation of rat endometriosis model by using raloxifene as a positive control for the evaluation of novel SERM compounds

Approximately 10% of women of reproductive age suffer from endometriosis, a potentially painful disease process and important cause of female infertility. Raloxifene, a commercially available SERM (selective estrogen receptor modulator) compound, used for the treatment of postmenopausal osteoporosis, has preclinically demonstrated its estrogen antagonist effect on uterine tissue in rats. There is potential that SERM compounds may become a viable treatment option for human endometriosis, although more investigation is needed. In this study, raloxifene was administered at various doses to determine the efficacy and an appropriate dose level for use as a positive control in a rat model of endometriosis. Prior to dose administration, all rats underwent a bilateral ovariectomy, autologous transplantation of uterine tissue onto the peritoneal surface of the abdominal wall, and implantation of a subcutaneous estrogen pellet (E2). Two separate postsurgical experiments were performed. In experiment 1, following a 4-wk recovery, the rats bearing implants were assigned to three groups: (1) removal of the E2 pellet and dosing vehicle only (n = 7); (2) E2 and vehicle (n = 6); and (3) E2 and raloxifene at 10.0 mg/kg (n = 6). In experiment 2, also following a 4-week recovery, the rats bearing implants were assigned to five groups (n = 8/group): (1) E2 and vehicle only; (2) E2 and raloxifene, 0.3 mg/kg/d; (3) E2 and raloxifene, 1.0 mg/kg/d; (4) E2 and raloxifene, 3.0 mg/kg/d; (5) E2 and raloxifene, 10.0 mg/kg/d. All rats were dosed orally BID for 14 d. At the end of the study, the implanted endometrium was remeasured and compared to the pretreatment measurement. The results from both studies demonstrated that Raloxifene at only one dose (10.0 mg/kg) displayed significant implant regression (p < .05). Subsequently, our rat endometriosis experimental model consistently uses the exogenous E2 pellet and raloxifene at 10 mg/kg, BID, as a positive control to help screen and compare novel SERM compounds.

Association analysis of the variant in the regulatory subunit of phosphoinositide 3-kinase (p85alpha) with Type 2 diabetes mellitus and hypertension in the Chinese Han population

AIMS

To determine whether variants in the gene for the regulatory subunit of phosphoinositide 3-kinase (p85alpha) are associated with Type 2 diabetes mellitus (Type 2 DM) and hypertension in a Chinese population.

METHODS

We performed a case-control study genotyping the Met326Ile and IVS4+82A>G polymorphisms in 494 patients with Type 2 DM and hypertension and 557 normal controls from the north of China. Individual genotypes were identified by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The IVS4+82A>G polymorphism was further confirmed by direct sequencing in 20 randomly selected cases.

RESULTS

The IVS4+82A>G polymorphism that is common in Caucasians was not detected in our population. Frequencies of genotypes and alleles of Met326Ile polymorphism were not significantly different between cases and controls in whole samples by univariate analysis. Logistic regression analysis demonstrated that Ile326Ile genotype was associated with a 2.085-fold (95% CI, 1.043-4.168, P = 0.0377) relative risk of diabetes and hypertension. After stratification by obesity, the frequency of Ile326Ile genotype in cases was higher than that in controls (18/304 vs. 13/510, P = 0.015) among non-obese individuals (BMI < 28 kg/m2). We did not find that this missense mutation was associated with blood pressure, glucose and blood lipids in the control group.

CONCLUSION

Our data indicate that the Met326Ile variation in the gene encoding the p85alpha protein might contribute to the increased risk of Type 2 DM and hypertension in Chinese.

Metabolism and disposition of gemfibrozil in Wistar and multidrug resistance-associated protein 2-deficient TR- rats

1. The roles of multidrug resistance-associated protein (Mrp) 2 deficiency and Mrp3 up-regulation were evaluated on the metabolism and disposition of gemfibrozil. 2. Results from in vitro studies in microsomes showed that the hepatic intrinsic clearance (CLint) for the oxidative metabolism of gemfibrozil was slightly higher (1.5-fold) in male TR- rats, which are deficient in Mrp2, than in wild-type Wistar rats, whereas CLint for glucuronidation was similar in both strains. 3. The biliary excretion of intravenously administered [14C]gemfibrozil was significantly impaired in TR-) rats compared with Wistar rats (22 versus 93% of the dose excreted as the acyl glucuronides over 72 h). Additionally, the extent of urinary excretion of radioactivity was much higher in TR- than in Wistar rats (78 versus 2.6% of the dose). 4. There were complex time-dependent changes in the total radioactivity levels and metabolite profiles in plasma, liver and kidney, some of which appeared to be related to the up-regulation of Mrp3. 5. Overall, it was demonstrated that alterations in the expression of the transporters Mrp2 and Mrp3 significantly affected the excretion as well as the secondary metabolism and distribution of [14C]gemfibrozil.

Characterisation of cartilage intermediate layer protein (CILP)-induced arthropathy in mice

OBJECTIVES

To characterise cartilage intermediate layer protein (CILP)-induced arthropathy in mice.

METHODS

The first and second halves of the nucleotide triphosphate pyrophosphohydrolase (NTPPHase) non-homologous region of human CILP were prepared as recombinant proteins (C1 and C2, respectively), including three overlapping fragments of C2 (C2F1, C2F2, and C2F3). C57BL/6 mice were immunised with these proteins to induce arthritis. In addition, a separate group of mice were immunised repeatedly with the mixture of C1 and C2 to see the effect of chronic immunisation. Arthritis developed in the mice, and cellular and humoral immune responses against CILP were analysed.

RESULTS

Immunisation with C2 and with the mixture C2F1/C2F2/C2F3 caused the severest arthritis to develop in mice. Immunisation with one of C1, C2F1, C2F2, or C2F3 caused milder arthritis, even though each of the fragments carried T cell epitopes. Immunisation either with C1 or C2 alone evoked cellular and humoral immune responses to both the C1 and C2 proteins. Further, the repeated immunisation with the C1/C2 mixture caused tendon calcification and bone irregularity, together with decreased NTPPH activity.

CONCLUSIONS

The results show that multiple T cell epitopes are needed for the development of CILP-induced arthritis, and present the characteristic new model of mild arthropathy accompanied by extra-articular calcifications. An immune response to putative murine CILP/NTPPH may be involved in the ectopic calcifications in the arthritic mice.

Genomic organization of human TCF12 gene and spliced mRNA variants producing isoforms of transcription factor HTF4

The human TCF12 gene, mapping to 15q21, encodes the helix-loop-helix transcription factor 4 (HTF4). A detailed analysis of this genomic region established the organization of the TCF12 gene. The gene includes 21 exons and is significantly larger than an average human gene. Preceding the second exon, two alternative acceptor sites for mRNA splicing yield two distinguishable transcripts (HTF4a and HTF4b) which differ in their 5' untranslated region but share identical coding sequences. Differential utilization of exon 15 in the TCF12 gene may reflect a mechanism producing a cell-type-specific protein (HTF4c). In addition, intron 5 in the TCF12 gene corresponds to the region involved in a translocation, t(9;15)(q22;q21), that results in a form of extraskeletal myxoid chondrosarcoma.

Attenuation of oxidant stress during reoxygenation by AMP 579 in cardiomyocytes

AMP 579, an adenosine A(1)/A(2) receptor agonist, has a strong anti-infarct effect when administered just before reperfusion. Because oxidative stress has been proposed to contribute to myocardial reperfusion injury, we tested whether AMP 579 can reduce the production of reactive oxidant species (ROS) during reoxygenation in cultured chick embryonic cardiomyocytes. The intracellular fluorescent probe 2',7'-dichlorofluorescin diacetate (DCFH) was used to detect ROS. The cells were subjected to 60 min of simulated ischemia, followed by either 15 min or 3 h of reoxygenation. AMP 579 (0.5 and 1 microM), when started 10 min before reoxygenation, significantly reduced ROS generation from 4.86 +/- 0.30 (arbitrary units) in untreated cells to 2.72 +/- 0.31 and 1.85 +/- 0.14, respectively (P < 0.05). Cell death that was assessed by propidium iodide uptake was markedly reduced by AMP 579 (49.6 +/- 4.7% of control cells vs. 25.4 +/- 2.4%, P < 0.05). In contrast, adenosine did not alter ROS generation or cell death. Attenuation of ROS production by AMP 579 was completely prevented by simultaneous exposure of cells to the selective adenosine A(2) antagonist 8-(13-chlorostyryl) caffeine. These results indicate that AMP 579 directly protects cardiomyocytes from reperfusion injury by a mechanism that attenuates intracellular oxidant stress. Furthermore, adenosine could not duplicate these effects.

[Analysis on the genetics of Hantavirus S85-46 isolated from Sichuan province]

OBJECTIVE

To understand the molecular and epidemic characteristics of Hantavirus S85-46 isolated from Sichuan province.

METHODS

RT-PCR products were amplified from S85-46 virus infected cells, cloned into T vector, sequenced and analyzed using DNASTAR software.

RESULTS

The homology of M segment of S85-46 strain and HTN type strain varied from 84.1%-99.7%, compared to 70.4%-70.9% with SEO strains. This result indicated that S85-46 strain belonged to hantavirus. The nucleotide sequence analyses indicated that S85-46 strain, LR1 strain and 76-118 strain were highly homologous. The two latter strains were isolated from Shaanxi province of China and South Korea respectively, which were far from Sichuan province of China. The nucleotide sequence analyses of S segment was similar to M segment.

CONCLUSION

The epidemic strains isolated from different regions may have been highly homologous.

[Inhibitive effect of puerarin on increased NO production by neonatal cardiomyocytes during hypoxia/reoxygenation injury]

OBJECTIVE

To investigate the effect of puerarin (Pue) on nitric oxide (NO) produced by neonatal rat cardiomyocytes during hypoxia/reoxygenation injury.

METHOD

NO contents in the culture supernatants sampled from different groups (control, model, and therapeutic groups with 1, 0.1, 0.01 g.L-1 Pue) at different time were assayed with nitrate reductase method.

RESULT

NO content of model increased after reperfusion (P < 0.01), while it increased sharply at 6 h after reperfusion and kept thereafter. Only at 6 h after reperfusion did Pue in these three doses inhibit NO production (P < 0.01) and kept to the 24 h after reperfusion.

CONCLUSION

Pue exerts inhibitive effect only after NO production is enhanced sharply during hypoxia/reperfusion injury in a dose-dependent trend.

Non-regulated and stimulated mechanisms cooperate in the nuclear accumulation of MEK1

MEKs, which operate within the ERK cascade, shuttle into the nucleus, but are rapidly exported from this location, forming an apparent cytosolic distribution both before and after stimulation. Two different mechanisms have been proposed for the nuclear translocation of MEKs. One of them involves a constant and non-regulated shuttling of MEKs into the nucleus operating both before and after mitogenic stimulation. The other mechanism seems to require the activity of MEKs and is facilitated in response to mitogenic stimulation. Here we show that these two mechanisms may coexist in the same cells. We found that leptomycin B (LMB), a potent inhibitor of nuclear export, induces a nuclear accumulation of MEKs, and this was significantly facilitated by stimulation of LMB-treated cells with EGF, TPA and peroxovanadate. The EGF-stimulated, but not the LMB-induced translocation was attenuated by MEK inhibitors and by using inactive forms of MEK1. We also show that LMB slightly activates the ERK cascade, but this activity only partially induces the nuclear accumulation of MEKs in cells treated by LMB alone. Thus, MEKs translocate into the nucleus by a combination of non-regulated and stimulated processes that contribute to the nuclear translocation of MEKs either in resting cells or upon mitogenic stimulation.

Role of opioid delta1 receptors, mitochondrial K(ATP) channels, and protein kinase C during cardiocyte apoptosis

Opioids attenuate cardiac injury after ischemia and reperfusion. We wanted to determine whether the protection of opioids is mediated by blocking cardiocyte apoptosis, and if so, to describe the role of opioid delta1 receptors and protein kinase C (PKC) in this effect. Chick embryonic cardiomyocytes were subjected to 12 h of simulated ischemia and then 12 h of re-oxygenation, which resulted in 54+/-3% (n=6) of cell apoptosis (n=6) as measured by flow cytometry. This result was consistent with DNA laddering and TUNEL assay. Preconditioning, elicited with three cycles of 1 min of simulated ischemia separated by 5 min of reoxygenation before prolonged simulated ischemia, reduced apoptosis (36+/-4%, n=6*). Pretreatment with BNTX (0.1 micromol/l), a selective opioid delta1 receptor blocker, abolished the effects of preconditioning (57+/-5%, n=6). The selective opioid delta receptor agonist BW373U86 (20 pmol/l) also attenuated apoptosis (39+/-3%, n=6* v control). These effects were abolished by 5-hydroxydecanoate (100 microm), a selective mitochondrial K(ATP) channel blocker (50+/-5%, n=6) and by Go-6976 (0.1 micromol/l), a specific PKC inhibitor. Both preconditioning and BW373U86 activated the PKC delta isoform of particulate fraction before simulated ischemia without effect on total and cytosolic fractions. Stimulation of opioid delta1 receptors activates mitochondrial K(ATP) channels and the PKC delta isoform in cultured ventricular myocytes. This is one important signal transduction pathway through which ischemic preconditioning blocks apoptosis and preserves cardiac function.

Comprehensive-trace level determination of methyltin compounds in aqueous samples by cryogenic purge-and-trap gas chromatography with flame photometric detection

A comprehensive method was developed for the sensitive and fast determination of trace levels of methyltin compounds in aqueous samples. Tin compounds in aqueous solution at pH 5 were converted to the corresponding volatile hydrides: CH3SnH3, (CH3)2SnH2, and (CH3)3SnH, by reaction with potassium borohydride. A CP-4010 purge and trap injector (PTI) was used to purge analyte species from water directly. The volatile derivatives were base-line separated on a capillary column in an Angilent-6890 gas chromatograph by a suitable temperature program and were detected by a flame photometric detector (FPD). The detection limits were 18 ng L-1 for monomethyltin, 12 ng L-1 for dimethyltin, and 3 ng L-1 for trimethyltin, respectively. This method was successfully applied to the determination of methyltin compounds in different aqueous samples.

Comparative cellular catabolism and retention of astatine-, bismuth-, and lead-radiolabeled internalizing monoclonal antibody

Monoclonal antibodies (mAbs) labeled with alpha-emitting radionuclides such as (211)At, (212)Bi, (213)Bi, and (212)Pb (which decays by beta-emission to its alpha-emitting daughter, (212)Bi) are being evaluated for their potential applications for cancer therapy. The fate of these radionuclides after cells are targeted with mAbs is important in terms of dosimetry and tumor detection.

METHODS

In this study, we attached various radionuclides that result in alpha-emissions to T101, a rapidly internalizing anti-CD5 mAb. We then evaluated the catabolism and cellular retention and compared them with those of (125)I- and (111)In-labeled T101. T101 was labeled with (211)At, (125)I, (205,6)Bi, (111)In, and (203)Pb. CD5 antigen-positive cells, peripheral blood mononuclear cells (PBMNC), and MOLT-4 leukemia cells were used. The labeled T101 was incubated with the cells for 1 h at 4 degrees C for surface labeling. Unbound activity was removed and 1 mL medium added. The cells were then incubated at 37 degrees C for 0, 1, 2, 4, 8, and 24 h. The activity on the cell surface that internalized and the activity on the cell surface remaining in the supernatant were determined. The protein in the supernatant was further precipitated by methanol for determining protein-bound and non-protein-bound radioactivity. Sites of internal cellular localization of radioactivity were determined by Percoll gradient centrifugation.

RESULTS

All radiolabeled antibodies bound to the cells were internalized rapidly. After internalization, (205,6)Bi, (203)Pb, and (111)In radiolabels were retained in the cell, with little decrease of cell-associated radioactivity. However, (211)At and (125)I were released from cells rapidly ((211)At < (125)I) and most of the radioactivity in the supernatant was in a non-protein-bound form. Intracellular distribution of radioactivity revealed a transit of the radiolabel from the cell surface to the lysosome. The catabolism patterns of MOLT-4 cells and PBMNC were similar.

CONCLUSION

(211)At catabolism and release from cells were somewhat similar to that of (125)I, whereas (205,6)Bi and (203)Pb showed prolonged cell retention similar to that of (111)In. These catabolism differences may be important in the selection of alpha-radionuclides for radioimmunotherapy.

Preparation and in vivo evaluation of linkers for 211At labeling of humanized anti-Tac

The syntheses, radiolabeling, antibody conjugation, and in vivo evaluation of new linkers for 211At labeling of humanized anti-Tac (Hu-anti-Tac), an antibody to the alpha-chain of the IL-2 receptor (IL-2Ralpha) shown to be a useful target for radioimmunotherapy are described. Synthesis of the organometallic linker precursors is accomplished by reaction of the corresponding bromo- or iodoaryl esters with bis(tributyltin) in the presence of a palladium catalyst. Subsequent conversion to the corresponding N-succinimidyl ester and labeling with 211At of two new linkers, N-succinimidyl 4-[211At]astato-3-methylbenzoate and N-succinimidyl N-(4-[211At]astatophenethyl)succinamate (SAPS), together with the previously reported N-succinimidyl 4-[211At]astatobenzoate and N-succinimidyl 3-[211At]astato-4-methylbenzoate, are each conjugated to Hu-anti-Tac. The plasma survival times of these conjugates are compared to those of directly iodinated (125I) Hu-anti-Tac. The N-succinimidyl N-(4-[211At]astatophenethyl)succinamate compound (SAPS) emerged from this assay as the most viable candidate for 211At-labeling of Hu-anti-Tac. SAPS, along with the directly analogous radio-iodinated reagent, N-succinimidyl N-(4-[125I]astatophenethyl)succinamate (SIPS), are evaluated in a biodistribution study along with directly iodinated (125I) Hu-anti-Tac. Blood clearance and biological accretion results indicate that SAPS is a viable candidate for further evaluation for radioimmunotherapy of cancer.

Identification of a critical lysine residue in apolipoprotein B-100 that mediates noncovalent interaction with apolipoprotein(a)

We have previously shown that lipoprotein(a) (Lp(a)) assembly involves an initial noncovalent interaction between sequences within apolipoprotein(a) (apo(a)) kringle IV types 5-8 and the amino terminus of apolipoprotein B-100 (sequences between amino acids 680 and 781 in apoB-100), followed by formation of a disulfide bond. In the present study, citraconylation of lysine residues in apoB-100 abolished the ability of the modified low density lipoprotein to associate with apo(a), thereby demonstrating a direct role for lysine residues in apoB in the first step of Lp(a) assembly. To identify specific lysine residues in the amino terminus of apoB that are required for the noncovalent interaction, we initially used an affinity chromatography method in which recombinant forms of apo(a) (r-apo(a)) were immobilized on Sepharose beads. Assessment of the ability of carboxyl-terminal truncations of apoB-18 to bind to r-apo(a)-Sepharose revealed that a 25-amino acid sequence in apoB (amino acids 680-704) bound specifically to apo(a) in a lysine-dependent manner; citraconylation of the lysine residues in the apoB derivative encoding this sequence abolished the binding interaction. Using fluorescence spectrometry, we found that a synthetic peptide corresponding to this sequence bound directly to apo(a); the peptide also reduced covalent Lp(a) formation. Lysine residues present in this sequence (Lys(680) and Lys(690)) were mutated to alanine in the context of apoB-18. We found that the apoB-18 species containing the Lys(680) mutation was incapable of binding to r-apo(a)-Sepharose columns, whereas the apoB-18 species containing the Lys(690) mutation exhibited slightly reduced binding to these columns. Taken together, our data indicate that Lys(680) is critical for the noncovalent interaction of apo(a) and apoB-100 that precedes covalent Lp(a) formation.

Altered regulation of ERK1b by MEK1 and PTP-SL and modified Elk1 phosphorylation by ERK1b are caused by abrogation of the regulatory C-terminal sequence of ERKs

ERK1b is an alternatively spliced form of ERK1, containing a 26-amino acid insertion between residues 340 and 341 of ERK1. Although under most circumstances the kinetics of ERK1b activation are similar to that of ERK1 and ERK2, we have previously found several conditions under which the activation of ERK1b by extracellular stimuli differs from that of other ERKs. We studied the molecular mechanisms that cause this differential regulation of ERK1b and found that ERK1b is altered in its ability to interact with MEK1 and this influenced its subcellular localization but not its kinetics of activation. ERK1b had a decreased ability to phosphorylate Elk1, but this did not change much the transcriptional activity of the latter. Importantly, the interaction of ERK1b with PTP-SL, which can act as a MAPK phosphatase, shortly after mitogenic stimulation, was significantly affected as well. Using mutants of ERK1b we found that the differential interaction of ERK1b with the three effectors is caused by the site of insertion that abrogates the cytosolic retention sequence/common docking motif of ERKs, and is not dependent on the actual sequence of the insert. Prolonged epidermal growth factor stimulation of Rat1 cells resulted in a differential inactivation and not activation of ERK1b as compared with ERK1 and ERK2. The reduced sensitivity to phosphatases without major differences in the kinetics of activation or activation of substrates, suggests that ERK1b plays a role in the transmission of extracellular signals under conditions of persistent stimulation, where ERK1b and MAPK phosphatases are induced, and the activity of ERK1 and ERK2 is suppressed.

Structure, function and regulation of the mitochondrial peripheral-type benzodiazepine receptor

Steroid biosynthesis begins with the transfer of cholesterol from intracellular stores into mitochondria. Through in vitro and in vivo studies using various steroidogenic cell models and with the help of pharmacological, biochemical, morphological and molecular approaches we demonstrated that the peripheral-type benzodiazepine receptor (PBR) is an 18 kDa mitochondrial protein that interacts with other proteins in the outer mitochondrial membrane to form a multimeric complex. PBR is required for the binding, uptake and release, upon ligand activation, of the substrate cholesterol. Thus, cholesterol becomes available to the inner mitochondrial membrane P450scc where steroid biosynthesis begins. The presence of mitochondrial PBR is also critical in maintaining outer mitochondrial membrane stability and in preventing apoptosis. Considering these functions of PBR and the fact that PBR is a ubiquitous protein, it is suggested that this drug receptor may serve as a target to control various mitochondrial and cell functions and to protect against experimentally or pathologically induced mitochondrial and cell toxicity.

Confirmation of susceptibility gene loci on chromosome 1 in northern China Han families with type 2 diabetes

OBJECTIVE

To confirm previous effort to identify type 2 diabetes susceptibility genes in a Northern Chinese population by conducting a new genome scan with both an increased number of type 2 diabetes families and a new set of microsatellite markers within the previously localized regions.

METHODS

A genome scan method was applied. After multiplexed PCR, electrophoreses, genescan and genotyping analysis, we obtained size information for all loci, and then a further study was done by both parametric and non-parametric linkage analysis to investigate the P values and Z values of these loci.

RESULTS

We surveyed 34 microsatellite markers which distributed within 5 regions along chromosome 1, and a total of 12,000 genotypes were screened. Evidence of linkage with diabetes was identified for 8 of the 34 loci. All P values of the 8 loci were lower than 0.05, and the highest Z value was 2.17. A very interesting finding is that all 5 markers at the p- terminal 1p36.3-1p36.23 region, spanning a long range of 16.9 cM, were identified to have a low P value of less than 0.05, which suggests that this region may contain multiple susceptibility genes. Regions 4 and 5 also confirmed the previous findings, and we narrowed these two regions to a 2.7 cM and 2.5 cM regions, respectively.

CONCLUSIONS

We further confirmed the results gained in the previous genome-wide scan using an increased number of NIDDM families and a new set of microsatellite markers lying within the initially localized regions. The fact that all 5 loci at the p- terminal region displayed a low P value of less than 0.05 suggests that more than 1 susceptibility gene may reside in this region.

Carbon nanotube single-electron transistors at room temperature

Room-temperature single-electron transistors are realized within individual metallic single-wall carbon nanotube molecules. The devices feature a short (down to approximately 20 nanometers) nanotube section that is created by inducing local barriers into the tube with an atomic force microscope. Coulomb charging is observed at room temperature, with an addition energy of 120 millielectron volts, which substantially exceeds the thermal energy. At low temperatures, we resolve the quantum energy levels corresponding to the small island. We observe unconventional power-law dependencies in the measured transport properties for which we suggest a resonant tunneling Luttinger-liquid mechanism.

Preconditioning attenuates apoptosis and necrosis: role of protein kinase C epsilon and -delta isoforms

Preconditioning reduces cardiomyocyte necrosis in vivo and in vitro, but it is unknown whether preconditioning blocks apoptosis. We wanted to compare the effects of preconditioning on necrosis and apoptosis in cardiomyocytes. Necrosis was detected with propidium iodide, and apoptosis was quantified by three complementary techniques: flow cytometry, TdT-mediated dUTP nick-end labeling assay, and DNA-laddering electrophoresis. Apoptosis increased with simulated ischemia time (6 h, 19 +/- 1%; 12 h, 27 +/- 2%; 18 h, 40 +/- 4%; 24 h, 54 +/- 4%; and 36 h, 83 +/- 4%; n = 6 for each group). Simulated ischemia and reoxygenation contributed equally to apoptosis (12-h ischemia, 27 +/- 2%, n = 6; 12-h ischemia and 12-h reoxygenation, 51 +/- 4%, n = 6; and 24-h ischemia, 54 +/- 5%, n = 8). Necrosis occurred primarily during reoxygenation; none was detected during simulated ischemia. Preconditioning with 10 min of simulated ischemia reduced necrosis (18 +/- 6%, n = 8) but had no effect on apoptosis. However, three 1-min cycles of simulated ischemia separated by 5 min of reoxygenation reduced necrosis and apoptosis similarly. The protein kinase C (PKC) inhibitors Go6976 (0.1 microM) or chelerythrene (4 microM) abolished the effect of preconditioning. Preconditioning selectively activated PKC epsilon but had no effect on PKC delta and on total PKC enzyme activity. Preconditioning protected against necrosis and apoptosis, but the preconditioning ischemia required for blocking apoptosis was less than that for reducing necrosis. Activation of PKC epsilon isoform is important in mediating the protection.

Role of nitric oxide and protein kinase C in ACh-induced cardioprotection

We examined the roles of nitric oxide and protein kinase C (PKC) in ACh-produced protection of cultured cardiomyocytes during simulated ischemia and reoxygenation. Cell viability was quantified using propidium iodide in chick embryonic ventricular myocytes. O(2) radicals were quantified using 2',7'-dichlorofluorescin diacetate. After a 10-min infusion of ACh (0.5 or 1 mM) and a 10-min drug-free period, we simulated ischemia for 1 h and reoxygenation for 3 h. ACh reduced cardiocyte death [32 +/- 4%; n = 6 and 23 +/- 4%; n = 7 (P < 0.05)] and attenuated oxidant stress during ischemia and reoxygenation in a concentration-dependent manner compared with controls (47 +/- 4%; n = 8; P < 0.05). The increase in O(2) radicals before simulated ischemia [357 +/- 49; n = 4 and 528 +/- 52; n = 8 vs. 211 +/- 34; n = 8; P < 0.05 (arbitrary units)] was abolished by the specific nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) and was markedly attenuated by N(G)-monomethyl-L-arginine (L-NMMA). L-NAME or L-NMMA blocked the protective effects of ACh, which selectively increased PKC-epsilon isoform activity in the particulate fraction. The PKC inhibitor Gö-6976 had no effect on O(2) radical production before simulated ischemia but it abolished the protection; therefore nitric oxide is a large component of ACh-generated O(2) radicals. Nitric oxide and O(2) radicals activate the PKC-epsilon isoform by which ACh protects against injury.

Signal transduction of opioid-induced cardioprotection in ischemia-reperfusion

BACKGROUND

Morphine reduces myocardial ischemia-reperfusion injury in vivo and in vitro. The authors tried to determine the role of opioid delta1 receptors, oxygen radicals, and adenosine triphosphate-sensitive potassium (KATP) channels in mediating this effect.

METHODS

Chick cardiomyocytes were studied in a flow-through chamber while pH, flow rate, oxygen, and carbon dioxide tension were controlled. Cell viability was quantified by nuclear stain propidium iodide, and oxygen radicals were quantified using molecular probe 2',7'-dichlorofluorescin diacetate.

RESULTS

Morphine (1 microM) or the selective delta-opioid receptor agonist BW373U86 (10 pM) given for 10 min before 1 h of ischemia and 3 h of reoxygenation reduced cell death (31 +/- 5%, n = 6, and 28 +/- 5%, n = 6 [P < 0.05], respectively, 53 +/- 6%, n = 6, in controls) and generated oxygen radicals before ischemia (724 +/- 53, n = 8, and 742 +/- 75, n = 8 [P < 0.05], respectively, vs. 384 +/- 42, n = 6, in controls, arbitrary units). The protection of morphine was abolished by naloxone, or the selective delta1-opioid receptor antagonist 7-benzylidenenaltrexone. Reduction in cell death and increase in oxygen radicals with BW373U86 were blocked by the selective mitochondrial KATP channel antagonist 5-hydroxydecanoate or diethyldithiocarbamic acid (1,000 microM), which inhibited conversion of O2- to H2O2. The increase in oxygen radicals was abolished by the mitochondrial electron transport inhibitor myxothiazoL Reduction in cell death was associated with attenuated oxidant stress at reperfusion.

CONCLUSION

Stimulation of delta1-opioid receptors generates oxygen radicals via mitochondrial KATP channels. This signaling pathway attenuates oxidant stress and cell death in cardiomyocytes.

[Surgical treatment and reconstruction for the patients with advanced-stage tonsillar cancer]

OBJECTIVE

To investigate the operative approach and reconstruction for the patients with advanced-stage tonsillar cancer.

METHOD

7 cases with advanced-stage tonsillar cancer were operated from Dec. 1994 to May 1999. Among them, 5 cases were operated through combined neck-mandible-oral cavity approach (CNMOCA) and with immediate reconstruction. Forearm free skin (FFS) flaps were applied in 3 cases. Pectoralis major myocutaneous (PMM) flaps were applied in 2 cases. 2 other cases were operated separately through approach of oral cavity or lateral pharynx. 6 cases were operated with radical neck dissection.

RESULT

5 cases who were operated through CNMOCA or with reconstruction were followed up from 1 year to 5 years and 3 months. They had not recurrence of tumor and complication. All had function recovery of speech. Swallowing or appearance is satisfactory in the 3 cases with FFS flaps. 2 Other cases died as recurrence of tumor in 1 year and 2 years and 10 months post-operation.

CONCLUSION

CNMOCA is able to provide a good exposure method to remove the extensive tumors completely for the patients with advanced stage tonsillar cancer. It is necessary to reconstruct immediately for the patients.

Analysis of the cat eye syndrome critical region in humans and the region of conserved synteny in mice: a search for candidate genes at or near the human chromosome 22 pericentromere

We have sequenced a 1.1-Mb region of human chromosome 22q containing the dosage-sensitive gene(s) responsible for cat eye syndrome (CES) as well as the 450-kb homologous region on mouse chromosome 6. Fourteen putative genes were identified within or adjacent to the human CES critical region (CESCR), including three known genes (IL-17R, ATP6E, and BID) and nine novel genes, based on EST identity. Two putative genes (CECR3 and CECR9) were identified, in the absence of EST hits, by comparing segments of human and mouse genomic sequence around two solitary amplified exons, thus showing the utility of comparative genomic sequence analysis in identifying transcripts. Of the 14 genes, 10 were confirmed to be present in the mouse genomic sequence in the same order and orientation as in human. Absent from the mouse region of conserved synteny are CECR1, a promising CES candidate gene from the center of the contig, neighboring CECR4, and CECR7 and CECR8, which are located in the gene-poor proximal 400 kb of the contig. This latter proximal region, located approximately 1 Mb from the centromere, shows abundant duplicated gene fragments typical of pericentromeric DNA. The margin of this region also delineates the boundary of conserved synteny between the CESCR and mouse chromosome 6. Because the proximal CESCR appears abundant in duplicated segments and, therefore, is likely to be gene poor, we consider the putative genes identified in the distal CESCR to represent the majority of candidate genes for involvement in CES.

Interleukin-6 induces androgen responsiveness in prostate cancer cells through up-regulation of androgen receptor expression

Interleukin-6 (IL-6) induces prostate cancer (CaP) cell proliferation in vitro. Several lines of evidence suggest that IL-6 may promote CaP progression through induction of an androgen response. In this work, we explored whether IL-6 induces androgen responsiveness through modulation of androgen receptor (AR) expression. We found that in the absence of androgen, IL-6 increased prostate-specific antigen (PSA) mRNA levels and activated several androgen-responsive promoters, but not the non-androgen responsive promoters in LNCaP cells. Bicalutamide, an antiandrogen, abolished the IL-6 effect and IL-6 could not activate the PSA and murine mammary tumor virus reporters in AR-negative DU-145 and PC3 cells. These data indicate the IL-6 induces an androgen response in CaP cells through the AR. Pretreatment of LNCaP cells with SB202190, PD98059, or tyrphostin AG879 [p38 mitogen-activated protein kinase (MAPK), MAP/extracellular signal-regulated protein kinase kinase 1/2, and ErbB2 MAPK inhibitors, respectively) but not wortmannin (PI3-kinase inhibitor) blocked IL-6-mediated induction of the PSA promoter, which demonstrates that IL-6 activity is dependent on a MAPK pathway. Finally, IL-6 activated the AR gene promoter, resulting in increased AR mRNA and protein levels in LNCaP cells. These results demonstrate that IL-6 induces AR expression and are the first report of cytokine-mediated induction of the AR promoter. Taken together, our results suggest that IL-6 induces AR activity through both increasing AR gene expression and activating the AR in the absence of androgen in CaP cells. These results provide a mechanism through which IL-6 may contribute to the development of androgen-independent CaP.

[Complete genome sequence analysis of the Hantavirus Z10 strain]

OBJECTIVE

Study on the complete genome sequence of Hantavirus Z10 strain which has been applied for inactivated vaccine production in China, to assess its molecular characteristics and the diversity with other hantaviruses.

METHODS

The total RNA were prepared from Z10 virus infected cells and the RT-PCR products was cloned into T vector, sequenced and analyzed by using DNASTAR software.

RESULTS

The Z10 complete genome, L segment is 6,553, M segment is 3,615, S segment is 1,701 nucleotides in length, with a single open reading frame encoding 2,151, 1,135, 429 amino acids respectively. Sequence homology comparison showed that the 3 segment nucleotide of Z10 strain were close to HTN type virus, but only 83.6-87.4% homology with other HTN viruses at the nucleotide level. The phylogenetic analysis was made on their nucleotide and amino acid sequences.

CONCLUSION

The results firstly demonstrates that Z10 strain is a new subtype of the Hantaan(HTN) type.

Synthesis and evaluation of a macrocyclic bifunctional chelating agent for use with bismuth radionuclides

The detailed synthesis of the bifunctional chelating agent 2-(p-isothiocyanatobenzyl)-1,4,7,10,13-pentaazacyclopentadecane-N,N',N",N"',N""-pentaacetic acid (BF_PEPA) is reported. This ligand was conjugated to monoclonal antibody B3 and the resultant immunoconjugate radiolabeled with (205,206)Bi. The in vivo stability of the radiolabeled immunoconjugate, and targeting characteristics were determined by biodistribution studies in A431 xenograft tumor-bearing mice sacrificed at 0.5, 1, 2, 4, and 24 hr. Results indicate that BF_PEPA appears to not be a suitable bifunctional chelating agent for sequestering isotopes of Bi(III) for radioimmunotherapy applications.