Structural basis of glutamate recognition by a dimeric metabotropic glutamate receptor

The metabotropic glutamate receptors (mGluRs) are key receptors in the modulation of excitatory synaptic transmission in the central nervous system. Here we have determined three different crystal structures of the extracellular ligand-binding region of mGluR1--in a complex with glutamate and in two unliganded forms. They all showed disulphide-linked homodimers, whose 'active' and 'resting' conformations are modulated through the dimeric interface by a packed alpha-helical structure. The bi-lobed protomer architectures flexibly change their domain arrangements to form an 'open' or 'closed' conformation. The structures imply that glutamate binding stabilizes both the 'active' dimer and the 'closed' protomer in dynamic equilibrium. Movements of the four domains in the dimer are likely to affect the separation of the transmembrane and intracellular regions, and thereby activate the receptor. This scheme in the initial receptor activation could be applied generally to G-protein-coupled neurotransmitter receptors that possess extracellular ligand-binding sites.

Flamingo, a seven-pass transmembrane cadherin, regulates planar cell polarity under the control of Frizzled

We identified a seven-pass transmembrane receptor of the cadherin superfamily, designated Flamingo (Fmi), localized at cell-cell boundaries in the Drosophila wing. In the absence of Fmi, planar polarity was distorted. Before morphological polarization of wing cells along the proximal-distal (P-D) axis, Fmi was redistributed predominantly to proximal and distal cell edges. This biased localization of Fmi appears to be driven by an imbalance of the activity of Frizzled (Fz) across the proximal/distal cell boundary. These results, together with phenotypes caused by ectopic expression of fz and fmi, suggest that cells acquire the P-D polarity by way of the Fz-dependent boundary localization of Fmi.

Constitutive activation of the 41-/43-kDa mitogen-activated protein kinase signaling pathway in human tumors

The 41-kDa and 43-kDa mitogen-activated protein (MAP) kinases play a pivotal role in the mitogenic signal transduction pathway and are essential components of the MAP kinase cascade, which includes MAP kinase kinase (MEK) and Raf-1. As aberrant activation of signal transducing molecules such as Ras and Raf-1 has been linked with cancer, we examined whether constitutive activation of the 41-/43-kDa MAP kinases is associated with the neoplastic phenotype of 138 tumor cell lines and 102 primary tumors derived from various human organs. Constitutive activation of the MAP kinases was observed in 50 tumor cell lines (36.2%) in a rather tissue-specific manner: cell lines derived from pancreas, colon, lung, ovary and kidney showed especially high frequencies with a high degree of MAP kinase activation, while those derived from brain, esophagus, stomach, liver and of hematopoietic origin showed low frequencies with a limited degree of MAP kinase activation. We also detected constitutive activation of the 41-/43-kDa MAP kinases in a relatively large number of primary human tumors derived from kidney, colon and lung tissues but not from liver tissue. Many tumor cells, in which point mutations of ras genes were detected, showed constitutive activation of MAP kinases, however, there were also many exceptions to this observation. In contrast, the activation of the 41-/43-kDa MAP kinases was accompanied by the activation of Raf-1 in the majority of tumor cells and was completely associated with the activation of MEK and p90rsk in all the tumor cells examined. These results suggest that the constitutive activation of 41-/43-kDa MAP kinases in tumor cells is not due to the disorder of MAP kinases themselves, but is due to the disorder of Raf-1, Ras, or some other signaling molecules upstream of Ras.

Phase I clinical trial and pharmacokinetic evaluation of NK911, a micelle-encapsulated doxorubicin

NK911 is a novel supramolecular nanocarrier designed for the enhanced delivery of doxorubicin (DXR) and is one of the successful polymer micelle systems to exhibit an efficient accumulation in solid tumours in mice. The purpose of this study was to define the maximum-tolerated dose (MTD) and dose-limiting toxicities (DLTs) of NK911 and to evaluate its pharmacokinetic profile in man. NK911 was given intravenously to patients with solid tumours every 3 weeks using an infusion pump at a rate of 10 mg DXR equivalent min⁻¹. The starting dose was 6 mg DXR equivalent m⁻², and the dose was escalated according to the accelerated titration method. A total of 23 patients participated in this study. Neutropenia was the predominant haematological toxicity, and grade 3 or 4 neutropenia was observed at doses of 50 and 67 mg m⁻². Common nonhaematological toxicities were mild alopecia, stomatitis, and anorexia. In the dose identification part of the study, DLTs were observed at a dose of 67 mg m⁻² (grade 4 neutropenia lasting more than 5 days). Thus, this dosage level was determined to be the MTD. Infusion-related reactions were not observed in any cases. The C_5 min and area under the concentration curve parameters of NK911 exhibited dose-dependent characteristics. Among the 23 patients, a partial response was obtained in one patient with metastatic pancreatic cancer. NK911 was well tolerated and produced only moderate nausea and vomiting at myelosuppressive dosages. The recommended phase II dose was determined to be 50 mg m⁻² every 3 weeks.

Characterization of 21 newly established esophageal cancer cell lines

Twenty-one esophageal cancer cell lines (KYSE series) have been established from the resected specimens of patients with esophageal cancer. Three lines, KYSE-30, KYSE-50, and KYSE-70, were derived from the implanted tumor of nude mice (initial passage); others were derived from resected specimens. Each cell line was morphologically distinct. Detailed cytogenetic analysis indicated that each cell line was karyotypically unique, and DNA fingerprint analysis showed no cross-contamination among cells. Doubling time ranged from 13.7 to 75.5 hours, and modal chromosome numbers ranged from 46 to 120. Most cell lines grew in monolayer, but two cell lines (KYSE-50 and KYSE-360) grew as floating cell aggregates. No correlation was demonstrated between the establishment of cell lines and cell differentiation. These cell lines are the first reported to be homogeneous and individually unique and may provide a useful model for the study of human esophageal cancer.

Recycling compartments and the internal vesicles of multivesicular bodies harbor most of the cholesterol found in the endocytic pathway

We employed our recently developed immuno-electron microscopic method (W. Möbius, Y. Ohno-Iwashita, E. G. van Donselaar, V. M. Oorschot, Y. Shimada, T. Fujimoto, H. F. Heijnen, H. J. Geuze and J. W. Slot, J Histochem Cytochem 2002; 50: 43-55) to analyze the distribution of cholesterol in the endocytic pathway of human B lymphocytes. We could distinguish 6 categories of endocytic compartments on the basis of morphology, BSA gold uptake kinetics and organelle marker analysis. Of all cholesterol detected in the endocytic pathway, we found 20% in the recycling tubulo-vesicles and 63% present in two types of multivesicular bodies. In the multivesicular bodies, most of the cholesterol was contained in the internal membrane vesicles, the precursors of exosomes secreted by B cells. Cholesterol was almost absent from lysosomes, that contained the bulk of the lipid bis(monoacylglycero)phosphate, also termed lysobisphosphatidic acid. Thus, cholesterol displays a highly differential distribution in the various membrane domains of the endocytic pathway.

Phase II study of CPT-11, a new camptothecin derivative, in metastatic colorectal cancer. CPT-11 Gastrointestinal Cancer Study Group

PURPOSE

A phase II study was conducted to evaluate the antitumor effect and toxicity of CPT-11 in patients with metastatic colorectal cancer.

PATIENTS AND METHODS

From December 1989 to March 1991, 67 patients with metastatic colorectal cancer were enrolled in this study. Sixty-three patients were assessable for toxicity and response. Their median age was 57 years (range, 24 to 72). Forty-six patients (73%) had a good performance status of 0 or 1. Fifty-one patients (81%) had received prior chemotherapy. The major sites of metastasis were liver (63%) and lung (44%). CPT-11 was administered as a 100 mg/m2 weekly intravenous infusion, or as 150 mg/m2 every 2 weeks. The dose was reduced based on the grade of leukopenia and diarrhea, if necessary.

RESULTS

A partial response was obtained in 17 of 63 assessable patients (27%; 95% confidence interval, 16% to 38%). The response rate in patients with prior radiotherapy or chemotherapy was 25% (13 of 52). Liver metastases showed a 15% (six of 40) response and lung metastases showed a 39% (11 of 28) response. The median duration of partial response was 127 days (range, 49 to 353) and the median overall duration of response was 208 days (range, 99 to 381). The major toxicities (> or = grade 3) were leukopenia (16%), diarrhea (13%), nausea and vomiting (13%), and alopecia (11%). Adverse effects were generally well tolerated and reversible. Treatment could be continued on an outpatient basis for patients without severe toxicity. Hemorrhagic cystitis was not encountered in this study.

CONCLUSION

CPT-11 showed promising antitumor activity against metastatic colorectal cancer that was resistant to prior therapy. Further clinical trials of combination chemotherapy using CPT-11 are justified.

CS-514, a competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase: tissue-selective inhibition of sterol synthesis and hypolipidemic effect on various animal species

CS-514 is a tissue-selective inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, a key enzyme in cholesterol synthesis. For the microsomal enzyme from rat liver, the mode of inhibition is competitive with respect to hydroxymethylglutaryl-CoA, and the Ki value is 2.3 X 10(-9) M. CS-514 also strongly inhibited the sterol synthesis from [14C]acetate in cell-free enzyme systems from rat liver and in freshly isolated rat hepatocytes; the concentrations required for 50% inhibition were 0.8 ng/ml and 2.2 ng/ml, respectively. On the other hand, the inhibition by CS-514 was much less in the cells from nonhepatic tissues such as freshly isolated rat spleen cells, and cultured mouse L cells and human skin fibroblasts. In addition, the cellular uptake of 14C-labeled CS-514 by isolated rat spleen cells or mouse L cells was less than one-tenth of that by isolated hepatocytes. These differences between hepatic and nonhepatic cells were further confirmed by the fact that CS-514 orally administered to rats inhibited sterol synthesis selectively in liver and intestine, the major sites of cholesterogenesis. CS-514 markedly reduced serum cholesterol levels in dogs, monkeys and rabbits, including Watanabe heritable hyperlipidemic (WHHL) rabbits, an animal model for familial hypercholesterolemia in man, but did not reduce those in rats and mice. In the former case, preferential lowering of atherogenic lipoproteins was observed in all of the animals tested. The biliary neutral sterols significantly decreased, whereas the amount of biliary bile acids was not affected by administration of the drug to dogs.

Biodiesel fuel production from plant oil catalyzed by Rhizopus oryzae lipase in a water-containing system without an organic solvent

A new enzymatic method of synthesizing methyl esters from plant oil and methanol in a solvent-free reaction system was developed. It is anticipated that such plant oil methyl esters can be used as a biodiesel fuel in the future. Lipase from Rhizopus oryzae efficiently catalyzed the methanolysis of soybean oil in the presence of 4-30 wt% water in the starting materials; however the lipase was nearly inactive in the absence of water. The methyl ester (ME) content in the reaction mixture reached 80-90 wt% by stepwise additions of methanol to the reaction mixture. The kinetics of the reaction appears to be in accordance with the successive reaction mechanism. That is, the oil is first hydrolyzed to free fatty acids and partial glycerides, and the fatty acids produced are then esterified with methanol. Although R. oryzae lipase is considered to exhibit 1(3)-regiospecificity, a certain amount of 1,3-diglyceride was obtained during the methanolysis and hydrolysis of soybean oil by R. oryzae lipase solution. Therefore, the high ME content in the reaction mixture is probably attributable to the acyl migration from the sn-2 position to the sn-1 or sn-3 position in partial glycerides.

Polarized Transport of Frizzled along the Planar Microtubule Arrays in Drosophila Wing Epithelium

Cells in a variety of developmental contexts sense extracellular cues that are given locally on their surfaces, and subsequently amplify the initial signal to achieve cell polarization. Drosophila wing cells acquire planar polarity along the proximal-distal (P-D) axis, in which the amplification of the presumptive cue involves assembly of a multiprotein complex that spans distal and proximal boundaries of adjacent cells. Here we pursue the mechanisms that place one of the components, Frizzled (Fz), at the distal side. Intracellular particles of GFP-tagged Fz moved preferentially toward distal boundaries before Fz::GFP and other components were tightly localized at the P/D cortex. Arrays of microtubules (MTs) were approximately oriented along the P-D axis and these MTs contributed to the formation of the cortical complex. Furthermore, there appeared to be a bias in the P-D MTs, with slightly more plus ends oriented distally. The hypothesis of polarized vesicular trafficking of Fz is discussed.

Effect of a corticotropin releasing hormone receptor antagonist on colonic sensory and motor function in patients with irritable bowel syndrome

BACKGROUND AND AIMS

Corticotropin releasing hormone (CRH) is a major mediator of the stress response in the brain-gut axis. Irritable bowel syndrome (IBS) is presumed to be a disorder of the brain-gut link associated with an exaggerated response to stress. We hypothesised that peripheral administration of alpha-helical CRH (alphahCRH), a non-selective CRH receptor antagonist, would improve gastrointestinal motility, visceral perception, and negative mood in response to gut stimulation in IBS patients.

METHODS

Ten normal healthy subjects and 10 IBS patients, diagnosed according to the Rome II criteria, were studied. The tone of the descending colon and intraluminal pressure of the sigmoid colon were measured at baseline, during rectal electrical stimulation (ES), and at recovery after administration of saline. Visceral perception after colonic distension or rectal ES was evaluated as threshold values on an ordinate scale. The same measurements were repeated after administration of alphahCRH (10 micro g/kg).

RESULTS

ES induced significantly higher motility indices of the colon in IBS patients compared with controls. This response was significantly suppressed in IBS patients but not in controls after administration of alphahCRH. Administration of alphahCRH induced a significant increase in the barostat bag volume of controls but not in that of IBS patients. alphahCRH significantly reduced the ordinate scale of abdominal pain and anxiety evoked by ES in IBS patients. Plasma adrenocorticotropic hormone and serum cortisol levels were generally not suppressed by alphahCRH.

CONCLUSION

Peripheral administration of alphahCRH improves gastrointestinal motility, visceral perception, and negative mood in response to gut stimulation, without affecting the hypothalamo-pituitary-adrenal axis in IBS patients.

Phosphorylation of the Cdc42 exchange factor Cdc24 by the PAK-like kinase Cla4 may regulate polarized growth in yeast

Rho-type GTPases control many cytoskeletal rearrangements, but their regulation remains poorly understood. Here, we show that in S. cerevisiae, activation of the CDK Cdc28-Cln2 at bud emergence triggers relocalization of Cdc24, the GEF for Cdc42, from the nucleus to the polarization site, where it is stably maintained by binding to the adaptor Bem1. Locally activated Cdc42 then polarizes the cytoskeleton in a manner dependent on its effectors Bni1 and the PAK-like kinase Cla4. In addition, Cla4 induces phosphorylation of Cdc24, leading to its dissociation from Bem1 at bud tips, thereby ending polarized bud growth in vivo. Our results thus suggest a dynamic temporal and spatial regulation of the Cdc42 module: Cdc28-Cln triggers actin polarization by activating Cdc42, which in turn restricts its own activation via a negative feedback loop acting on its GEF Cdc24.

Purification and characterization of thrombopoietin

A thrombopoietic factor, termed thrombopoietin (TPO), was highly purified directly from the plasma of sublethally irradiated 1,100 rats by measuring the production of megakaryocytes from a highly enriched population of rat megakaryocyte progenitor cells (CFU-MK). The rat plasma TPO is a glycoprotein and strongly hydrophobic. The total activity and purification yields obtained were about 29% and 1.49 x 10(8), respectively. The amino acid sequences of the two peptide fragments prepared from the purified 19 kDa TPO were analyzed, and used for the cloning of rat and human TPO cDNAs. It was found that the 19 kDa TPO was truncated but comprised at least 163 amino acids. The sequence of human TPO cDNA revealed that the TPO was identical to the c-Mpl ligand. Both rat and human TPOs expressed in COS-1 cells exhibited significant activity toward the CFU-MK in vitro, and were active in stimulating platelet production in mice. These results indicate that a thrombopoietic factor originally found in the irradiated rat plasma is a ligand for the rat c-Mpl.

Implications of plasma concentrations of adiponectin in patients with coronary artery disease

OBJECTIVE

To investigate whether concentrations of plasma adiponectin constitute a significant coronary risk factor, with particular focus on the relation between plasma concentrations of adiponectin and the development of acute coronary syndrome (ACS).

SUBJECTS AND METHODS

Plasma concentrations of adiponectin were measured in 123 patients with coronary artery disease (CAD) and in 17 control participants. Patients were divided into three groups according to condition type: acute myocardial infarction (AMI) group (n = 59), unstable angina pectoris (UAP) group (n = 28), and stable angina pectoris (SAP) group (n = 36).

RESULTS

Plasma concentrations of adiponectin correlated negatively with body mass index (r = -0.18, p < 0.05), serum triglyceride (r = -0.25, p < 0.01), and fasting glucose concentrations (r = -0.21, p < 0.05), but correlated positively with age (r = 0.26, p < 0.01), high density lipoprotein cholesterol concentrations (r = 0.35, p < 0.01), and low density lipoprotein particle size (r = 0.37, p < 0.01). Plasma concentrations of adiponectin in patients with ACS, in both the AMI and UAP groups, were significantly lower than those in patients with SAP and in the control group (ACS, 6.5 (3.0) microg/ml; SAP, 11.3 (5.9) micro g/ml; control 12.8 (4.3) microg/ml; p < 0.01). Additionally, plasma concentrations of adiponectin in patients with CAD (7.9 (4.6) microg/ml, p < 0.01) were significantly lower than in the control group. There were, however, no significant differences between patients with SAP and the control group (p = 0.36). Multiple logistic regression analysis showed that smoking, fasting glucose concentration, and low log adiponectin concentration correlated independently with the development of an ACS.

CONCLUSIONS

The findings suggest that measurement of plasma concentrations of adiponectin may be of use for assessing the risk of CAD and may be related to the development of ACS.

Phase II study of a combination of irinotecan and cisplatin against metastatic gastric cancer

PURPOSE

A phase II study of a combination chemotherapy regimen of cisplatin (CDDP) and irinotecan (CPT-11) was conducted to assess its efficacy and feasibility in patients with metastatic gastric cancer.

PATIENTS AND METHODS

Eligibility criteria included the following: (1) histologically proven gastric cancer with measurable metastatic lesions, (2) performance status of 2 or less, (3) age of 75 years or younger, (4) one or no prior chemotherapy regimens, (5) adequate bone marrow, liver, renal, and cardiac functions, and (6) written informed consent. The treatment consisted of CPT-11 (70 mg/m2) on day 1 and day 15 and CDDP (80 mg/m2) on day 1, repeated every 4 weeks.

RESULTS

Forty-four patients were entered onto the study. The overall response rate was 48% (21 of 44 patients, 95% confidence interval [CI], 33% to 63%) and included one complete remission (2%). The response rate of the patients who had not received prior chemotherapy was 59% (17 of 29 patients, 95% CI, 39% to 77%). The median survival time was 272 days for all patients and 322 days for the 29 patients who had not received prior chemotherapy. Grade 4 neutropenia was observed in 25 patients (57%), and grade 3 or 4 diarrhea was observed in nine patients (20%). Other adverse reactions were mild. No treatment-related deaths occurred.

CONCLUSION

This combination chemotherapy regimen is active and well tolerated. It may be an appropriate regimen for future phase III trials.

Apoptosis of vascular endothelial cells by fibroblast growth factor deprivation

Survival and proliferation of many types of vascular endothelial cells are influenced by fibroblast growth factor (FGF)1. Removal of FGF from the medium of human umbilical vein endothelial cells (HUVEC) in culture resulted in death of the cells. Here we show that the death caused by deprivation of FGF is active death or apoptosis, and the process of apoptosis can be inhibited by cycloheximide, an inhibitor of protein synthesis. The present study shows apoptosis occurs in endothelial cells in culture. The process of active death of vascular endothelial cells is inhibited by growth factor. This mechanism may be important for the regulation of vascular organization through the degeneration of vessels.

Selective binding of perfringolysin O derivative to cholesterol-rich membrane microdomains (rafts)

There is increasing evidence that sphingolipid- and cholesterol-rich microdomains (rafts) exist in the plasma membrane. Specific proteins assemble in these membrane domains and play a role in signal transduction and many other cellular events. Cholesterol depletion causes disassembly of the raft-associated proteins, suggesting an essential role of cholesterol in the structural maintenance and function of rafts. However, no tool has been available for the detection and monitoring of raft cholesterol in living cells. Here we show that a protease-nicked and biotinylated derivative (BCtheta) of perfringolysin O (theta-toxin) binds selectively to cholesterol-rich microdomains of intact cells, the domains that fulfill the criteria of rafts. We fractionated the homogenates of nontreated and Triton X-100-treated platelets after incubation with BCtheta on a sucrose gradient. BCtheta was predominantly localized in the floating low-density fractions (FLDF) where cholesterol, sphingomyelin, and Src family kinases are enriched. Immunoelectron microscopy demonstrated that BCtheta binds to a subpopulation of vesicles in FLDF. Depletion of 35% cholesterol from platelets with cyclodextrin, which accompanied 76% reduction in cholesterol from FLDF, almost completely abolished BCtheta binding to FLDF. The staining patterns of BCtheta and filipin in human epidermoid carcinoma A431 cells with and without cholesterol depletion suggest that BCtheta binds to specific membrane domains on the cell surface, whereas filipin binding is indiscriminate to cell cholesterol. Furthermore, BCtheta binding does not cause any damage to cell membranes, indicating that BCtheta is a useful probe for the detection of membrane rafts in living cells.

A phase I and pharmacokinetic study of NK105, a paclitaxel-incorporating micellar nanoparticle formulation

This phase I study was designed to examine the maximum tolerated dose (MTD), the dose-limiting toxicities (DLTs), the recommended dose (RD) for phase II, and the pharmacokinetics of NK105, a new polymeric micelle carrier system for paclitaxel (PTX). NK105 was administered as a 1-h intravenous infusion every 3 weeks, without antiallergic premedication. The starting dose was 10 mg m⁻², and the dose was escalated according to the accelerated titration method. Nineteen patients were recruited. The tumour types treated included pancreatic (n=11), bile duct (n=5), gastric (n=2), and colonic (n=1) cancers. Neutropenia was the most common haematological toxicity. A grade 3 fever developed in one patient given 180 mg m⁻². No other grades 3 or 4 nonhaematological toxicities, including neuropathy, was observed during the entire study period. DLTs occurred in two patients given 180 mg m⁻² (grade 4 neutropenia lasting for more than 5 days). Thus, this dose was designated as the MTD. Grade 2 hypersensitivity reactions developed in only one patient given 180 mg m⁻². A partial response was observed in one patient with pancreatic cancer. The maximum concentration (C_max) and area under the concentration (AUC) of NK105 were dose dependent. The plasma AUC of NK105 at 150 mg m⁻² was approximately 15-fold higher than that of the conventional PTX formulation. NK105 was well tolerated, and the RD for the phase II study was determined to be 150 mg m⁻² every 3 weeks. The results of this phase I study warrant further clinical evaluation.

Molecular cloning and chromosomal localization of the human thrombopoietin gene

The complete gene for human thrombopoietin (TPO) has been cloned by screening a human genomic library using human TPO cDNA as a probe. This gene is 6.2 kb in length and contains six exons and five introns. It is shown that the human genome contains a single copy of the human TPO gene according to Southern blotting analysis. The transcription initiation site was determined by S1 nuclease mapping. The human TPO gene expressed TPO activity when transfected into COS-1 cells. The human TPO gene has been mapped to chromosome 3q27 by in situ hybridization using a biotin-labeled probe.

Stability of transpedicle screwing for the osteoporotic spine. An in vitro study of the mechanical stability

The influence of bone mineral density on the stability of transpedicle screwing was studied in the human cadaveric lumbar vertebrae. The pull-out force correlated with bone mineral density. The tilting moment (load needed to tilt the screw 4 degrees cranially at the screw-plate junction) and the cut-up force (load needed to tip the end plate up by the screw) correlated with bone mineral density. A correlation was also found between the maximum insertion torque of the screw and bone mineral density. The maximum insertion torque correlated with the pull-out force, the tilting moment, and the cut-up force. In the cyclic tilting test (200 cycles), the mean value of the tilting moment at the 200th cycle was 67.4 +/- 6.1%, compared with the first cycle. The results suggest that preoperative measurement of BMD is necessary for transpedicle screwing in osteoporotic cases, and that the cyclic tilting motion decrease its mechanical stability. The authors have also concluded that the maximum insertion torque could predict the mechanical stability.

Asymmetric colocalization of Flamingo, a seven-pass transmembrane cadherin, and Dishevelled in planar cell polarization

The Drosophila wing provides an appropriate model system for studying genetic programming of planar cell polarity (PCP) [1-4]. Each wing cell respects the proximodistal (PD) axis; i.e., it localizes an assembly of actin bundles to its distalmost vertex and produces a single prehair. This PD polarization requires the redistribution of Flamingo (Fmi), a seven-pass transmembrane cadherin, to proximal/distal cell boundaries; otherwise, the cell mislocalizes the prehair [5]. Achievement of the biased Fmi pattern depends on two upstream components in the PCP signaling pathway: Frizzled (Fz), a receptor for a hypothetical polarity signal, and an intracellular protein, Dishevelled (Dsh) [6-8]. Here, we visualized endogenous Dsh in the developing wing. A portion of Dsh colocalized with Fmi, and the distributions of both proteins were interdependent. Furthermore, Fz controlled the association of Dsh with cell boundaries, which association was correlated with the presence of hyperphosphorylated forms of Dsh. Our results, together with a recent study on Fz distribution [9], support the possibility that Fz, Dsh, and Fmi constitute a signaling complex and that its restricted localization directs cytoskeletal reorganization only at the distal cell edge.

Functional anatomy of the posterolateral structures of the knee

The major supporting structures of the posterolateral knee were noted to be composed of three components: the fabellofibular ligament, the arcuate ligament, and popliteus muscle with origin from fibular head. We classified this area of the knee into seven major anatomic variants. Popliteus tendon is composed of two parts: the anterior and the posterior fibers. The anterior fibers become tight, while the posterior fibers become lax as the knee was flexed. This phenomenon is more pronounced when the tibia is rotated externally. The midpoint between the anterior and the posterior fibers insertions on the femur appeared to be the isometric point of the popliteus tendon.

Phase I and pharmacokinetic study of MCC-465, a doxorubicin (DXR) encapsulated in PEG immunoliposome, in patients with metastatic stomach cancer

BACKGROUND

MCC-465 is an immunoliposome-encapsulated doxorubicin (DXR). The liposome is tagged with polyethylene glycol (PEG) and the F(ab')2 fragment of human monoclonal antibody GAH, which positively reacts to >90% of cancerous stomach tissues, but negatively to all normal tissues. In preclinical studies, MCC-465 showed superior cytotoxic activity against several human stomach cancer cells compared with DXR or DXR-incorporated PEG liposomes. The main purpose of this trial was to define the maximum tolerated dose (MTD), dose limiting toxicity (DLT), recommended phase II dose and pharmacokinetics (PK) of MCC-465.

PATIENTS AND METHODS

Patients with metastatic or recurrent stomach cancer were eligible for entry. The initial dose was 6.5 mg/m2. MCC-465 was administered as a 1-h infusion every 3 weeks and the treatment continued for up to six cycles.

RESULTS

Twenty-three patients received a total of 62 cycles at the 6.5-45.5 mg/m2 dose level. DLTs were myelosuppression and appetite loss at the 45.5 mg/m2 dose level. Other toxicities were mild. Neither palmar-plantar erythrodysesthesia nor cardiotoxicity was observed. Acute reactions related to infusion were observed commonly in 16 patients over the entire dose range. While no antitumor response was observed, stable disease (SD) was observed in 10 out of 18 evaluable patients. The pharmacokinetic study showed a similar AUC and Cmax to Doxil.

CONCLUSION

MCC-465 was well tolerated. The recommended dose for a phase II study of MCC-465, for a 3-week schedule, is considered to be 32.5 mg/m2 in an equivalent amount of DXR.