The use of a permanent magnetic resonance imaging system for radiotherapy treatment planning of bone metastases

PURPOSE

To evaluate the usefulness of magnetic resonance (MR) imaging-based radiotherapy treatment planning (RTTP) for bone metastases in clinical applications.

METHODS AND MATERIALS

MR imaging-based RTTP was carried out for 28 patients with bone metastases using a permanent magnetic MR unit. Twenty-three patients received MR imaging-assisted X-ray simulation, and five underwent MR simulation. In MR imaging-assisted X-ray simulation, the radiation fields defined by an X-ray simulator were modified based on MR information scanned in the exact treatment position using MR skin markers. In MR simulation, both isocenter position and field size were determined on MR images and projected onto the patient's skin.

RESULTS

All lesions unclear on other imaging modalities could be clearly identified on MR imaging. Of the 23 patients receiving MR imaging-assisted X-ray simulation, modification of the original radiation field was necessary in 14 patients (extended in 9, reduced in 4, and completely changed in 1). In MR simulation, appropriate radiation fields could be easily and quickly determined using MR imaging.

CONCLUSION

Methods for MR imaging-based RTTP were developed and clinically implemented for patients with bone metastases, and they were shown to be useful for improving the accuracy of the tumor location. They would provide better therapeutic/palliative benefit to particular patients with bone metastases and could also be applied to other lesions in the future.

Reproducibility of geometric distortion in magnetic resonance imaging based on phantom studies

BACKGROUND AND PURPOSE

Image distortion is one of the major drawbacks of magnetic resonance (MR) imaging for use in radiotherapy treatment planning (RTTP). In this study, the reproducibility of MR imaging distortion was evaluated by repeated phantom measurements.

MATERIALS AND METHODS

A grid-pattern acrylic phantom was scanned with a 0.2-Tesla permanent magnetic unit. We repeated a series of scans three times to evaluate the reproducibility of the distortion. In each series, co-ordinates at 432 intersections of the grid were measured for both T1- and T2-weighted spin-echo (SE) pulse sequences. Positional displacements and their variations at the intersections were calculated.

RESULTS

Averages of the displacements were distributed between 1.58 and 1.74 mm, and maximum values (MAX) between 12.6 and 15.0 mm. Within 120 mm of the image center, the average values ranged from 0.73 to 0.80 mm, and from 3.4 to 5.0 mm for MAX. The absolute values of the positional variations among three series were distributed between 0.41 and 0.88 mm for average values, and between 1.4 and 4.5 mm for MAX.

CONCLUSIONS

The positional variations were mostly within 3 pixels, and most of the positional displacements within the radius of 120 mm of the image center were 2 mm or less. Therefore, it will be possible to use this MR system in RTTP under limited situations, although careful applications are required for RTTP of the body. The development of a computer program to correct image distortion is expected.

Actinin-4 is preferentially involved in circular ruffling and macropinocytosis in mouse macrophages: analysis by fluorescence ratio imaging

We have applied fluorescence ratio imaging to the analysis of an actin-binding protein concentration relative to F-actin in macrophages, in order to explore the role of a novel (alpha)-actinin isoform, actinin-4, relative to that of the classical isoform, actinin-1. Conventional immunofluorescence images showed that both isoforms were enriched in F-actin-rich regions such as cell surface ruffles. However, ratio images further demonstrated that actinin-4 concentrations relative to F-actin were higher in peripheral inward curved ruffles and dorsal circular ruffles, presumed precursor forms of macropinosomes, than in straight linear ruffles, while actinin-1 concentrations were uniform among the different types of ruffles. Macropinosome pulse-labeling and chase experiments indicated that actinin-4 was also closely associated with newly formed macropinosomes and gradually dissociated with their maturation. Consistent with ratio imaging data, macrophages scrape-loaded with anti-actinin-4 showed a more reduced rate of macropinocytosis than those loaded with anti-actinin-1. Altogether, these results indicate that actinin-4 and actinin-1 contribute differently to F-actin dynamics, that actinin-4 is more preferentially involved in early stages of macropinocytosis than actinin-1. A similar redistribution of actinin-4 was also observed during phagocytosis, suggesting that actinin-4 may play the same role in the two mechanistically analogous types of endocytosis, i.e. macropinocytosis and phagocytosis.

Increased levels of advanced glycosylation end products in the kidney and liver from spontaneously diabetic Chinese hamsters determined by immunochemical assay

Increased levels of advanced glycosylation end products (AGEs) have been reported in tissues in association with diabetes mellitus. Thus, we measured tissue AGE levels and detected an accumulation of AGEs in the kidney and liver from spontaneously diabetic Chinese hamsters (CHAD) to determine the relationship between AGEs and diabetes mellitus. Diabetic CHAD aged 12 to 13 months were studied together with age-matched nondiabetic CHAD. We used an AGE-specific noncompetitive enzyme-linked immunosorbent assay (ELISA) with polyclonal anti-AGE-bovine serum albumin (BSA) antibody to measure tissue AGE levels. The samples extracted from the kidney and liver obtained from diabetic and nondiabetic CHAD reacted with anti-AGE-BSA antibody. When the absorbance of standard AGE-BSA (0.1 microg/mL) was expressed as 1 U, AGE levels in the kidney and liver from diabetic CHAD were significantly increased as compared with nondiabetic CHAD (kidney, 0.26 +/- 0.05 v 0.10 +/- 0.03 U/microg protein, P< .01; liver, 0.20 +/- 0.03 v 0.09 +/- 0.02 U/microg protein, P< .01). Positive AGE staining was observed in the renal cortex, especially in the tubules of diabetic CHAD, but little AGE staining was observed in the glomerulus by the immunohistochemical study. AGE staining was diffuse in the hepatocytes. These AGE levels were significantly correlated with fasting plasma glucose and glycated hemoglobin (P < .01, respectively). In conclusion, we have confirmed that AGE structures were expressed in the kidney and liver from CHAD, and these AGE levels were increased in diabetic CHAD. AGE staining was observed in the renal tubules and hepatocytes. Tissue AGE levels were positively correlated with glycemic control in CHAD.

Clinical significance of tenascin-C expression in osteosarcoma: tenascin-C promotes distant metastases of osteosarcoma

Tenascin-C (TN-C) is one of extracellular matrix glycoproteins. We have immunohistochemically examined the TN-C expression of 33 primary osteosarcoma paraffin-embedded samples. The TN-C expression of the patient group with metastases was higher than that of the group without metastases at significant difference, and the survival curves show a tendency for poor outcome in the high grade staining group. Moreover, the supplemental TN-C had an effect of easier migration of a human osteosarcoma cell line (HOS) in vitro. The results may suggest that TN-C help osteosarcoma cells to migrate and to metastasize.

Comparative analysis of brain proteins from p53-deficient mice by two-dimensional electrophoresis

p53 is a tumor suppressor protein that regulates many cellular processes including the cell cycle, DNA repair, and apoptosis. It also serves as a critical regulator of neuronal apoptosis in the central nervous system (CNS). To elucidate the role of p53 in the CNS, brain proteins of p53 knock-out mice (p53-/-) were analyzed by two-dimensional gel electrophoresis (2-DE) and compared with those from p53 wild type (p53+/+) mice. Six types of brain tissue (temporal cortex, cerebellum, hippocampus, striatum, olfactory bulb, and cervical spinal cord) and other control tissues (lung and blood) from 18-week-old non-stress-induced mice were analyzed. The morphology of brains from p53-/- mice appeared to be normal and identical to that of p53+/+ mice, although lungs showed diffuse tumors that may have been caused by p53 deficiency. Comparative 2-D gel analysis showed that, on average, 7 of 886 spots from brain tissue were p53-/- specific, whereas 12 of 1008 spots from lung tissue were p53-/- specific. N-terminal amino acid sequence was determined for p53-/- specific proteins. In all brain tissues from p53-/- mice, a newly identified mouse mitochondrial NADH-ubiquinone oxidoreductase 24 kDa subunit showed decreased expression, and apolipoprotein A1 acidic forms showed increased expression. In addition, brain-type creatine kinase B chain and tubulin beta-5 N-terminal fragment were increased in the p53-/- cerebellum, and a new protein in mouse, hydroxyacylglutathione hydrolase (glyoxalase II) was decreased in the temporal cortex of p53-/- mice. The alterations in protein expression identified in this study may imply a p53-related brain function. This is the first proteomic analysis on the p53-/- mouse brain, and further information based on this study will provide new insights into the p53 function in the CNS.

Neoadjuvant chemotherapy by transcatheter arterial infusion method for uterine cervical cancer

PURPOSE

The effects of transcatheter intraarterial infusion of anticancer drugs on the prognosis of cervical cancer were retrospectively studied.

MATERIALS AND METHODS

Two or three sessions of transcatheter arterial infusion therapy were performed in 97 patients with primary uterine cervical cancer. The number of patients in stage I, II, III, or IV were 15, 37, 34, and 11, respectively. The drugs infused were cisplatin (60-70 mg/m2), doxorubicin hydrochloride (30-40 mg/m2), mitomycin (15 mg/m2), and 5-fluorouracil (500 mg/body). They were infused via the bilateral internal iliac arteries. Seventy-five patients of the 97 (78%) underwent radical hysterectomy after arterial infusion: stage I (14 of 15), stage II (31 of 37), stage III (25 of 34), and stage IV (5 of 11). Three stage II and nine stage III patients received radical radiation therapy. The other 10 patients (one with stage I, three with stage II, and six with stage IV) did not receive an operation and radiation therapy after arterial infusion because of their distant metastases at the time of operation. Thirty-eight patients of 75 (51%) received postoperative radiation therapy.

RESULTS

The complete histologic response rates (no active cancer cells) after arterial infusion were four of 14, four of 31, six of 25, and one of five for stages I, II, III, and IV. The histologic response rates, which showed no parametrial invasion after arterial infusion, were 12 of 14, 24 of 31, and 15 of 25 for stages I, II, and III. The histologic response rates, which demonstrated no lymph node metastases after arterial infusion, were 12 of 14, 24 of 31, and 19 of 25 for stages I, II, and III. The overall 5-year survival rates of the patients with stages I, II, and III were 93.3%, 58.7%, and 69.7%, respectively. The 5-year survival rates of the operated patients with stages I, II, and III were 100%, 60.5%, and 63.6%, respectively. The 5-year survival rates of the irradiated patients with stage III was 87.5%. Leukocytopenia and thrombocytopenia occurred as an acute complication in 75% and 79% of the patients, respectively. As a late complication, ileus occurred in 7%.

CONCLUSION

Arterial infusion may improve the prognosis of patients with cervical cancer without increasing the incidence of late complications.

SYT-SSX fusion proteins in synovial sarcomas: detection and characterization with new antibodies

To identify and characterize the SYT-SSX fusion proteins in synovial sarcomas, we developed two polyclonal antibodies against the N-terminal part and for the C-terminal part of the SYT-SSX2 protein. Specificity was demonstrated on COS-7 cells transfected with two subtypes of SYT-SSX fusion genes, SYT-SSX1 and SYT-SSX2. Both antibodies recognized a single protein of 61 kDa in an immunoprecipitation of the transfected COS-7 cell lysates. These antibodies also detected the native protein of 61 kDa in the lysate of a human synovial sarcoma cell line (HS-SY41) with immunoprecipitation, and in extracts of human synovial sarcomas with western blot analysis. An immunohistochemical study, using human synovial sarcoma tissues, demonstrated that the SYT-SSX fusion proteins localized in the nucleus of the tumor cells. These antibodies provide a useful method for studying the expression of the SYT-SSX fusion proteins.

Neonatal thrombocytopenia induced by maternal anti-HLA antibodies: a potential side effect of allogenic leukocyte immunization for unexplained recurrent aborters

Allogenic leukocyte immunization is one of several treatments tried for unexplained recurrent aborters, and is reported to have few maternal and neonatal side effects after the immunotherapy having been reported to date. In the present study, we report a rare case of neonatal thrombocytopenia (41000 cells/microl) observed in a female infant delivered by an unexplained habitual aborter. The mother was immunized with her husband's leukocytes once before pregnancy and twice at the 5th and 6th week of her successful pregnancy. Serological studies using mixed passive hemagglutination assays (MPHA) showed that maternal serum did not contain any antibodies which were reactive to 11 platelet-specific antigens, or to granulocyte antigens extracted from 9 persons. Lymphocyte cytotoxicity tests, however, showed that maternal serum but not infant serum had anti-HLA antibodies against both paternal and infant lymphocytes. Moreover, the maternal serum was found to have anti-HLA IgGs against platelet antigens extracted from the father and the infant. It is highly likely that this case of neonatal thrombocytopenia was caused by transplacental perfusion of maternal anti-HLA antibodies whose production was induced or enhanced by the allogenic leukocytes immunizations.

Calcium influx triggers the sequential proteolysis of extracellular and cytoplasmic domains of E-cadherin, leading to loss of beta-catenin from cell-cell contacts

Cadherins are major cell-cell adhesion molecules in both tumor and normal tissues. Although serum levels of soluble E-cadherin have been shown to be higher in the cancer patients than in healthy volunteers, the detail mechanism regulating release of soluble E-cadherin remains to be elucidated. Here we show that the ectodomain of E-cadherin is proteolytically cleaved from some cancer cells by a membrane-bound metalloprotease to yield soluble form, and the residual membrane-tethered cleavage product is subsequently degraded by intracellular proteolytic pathway. Futhermore, we show that extracellular calcium influx, that is induced by mechanical scraping of cells or ionomycin treatment, enhances the metalloprotease-mediated E-cadherin cleavage and the subsequent degradation of the cytoplasmic domain. Immunocytochemical analysis demonstrates that the sequential proteolysis of E-cadherin triggered by the calcium influx results in translocation of beta-catenin from the cell-cell contacts to cytoplasm. Our data suggest that calcium influx-induced proteolysis of E-cadherin not only disrupts the cell-cell adhesion but also activates beta-catenin-mediated intracellular signaling pathway, potentially leading to alterations in motility and proliferation activity of cells.

A novel NE-dlg/SAP102-associated protein, p51-nedasin, related to the amidohydrolase superfamily, interferes with the association between NE-dlg/SAP102 and N-methyl-D-aspartate receptor

The membrane-associated guanylate kinase proteins have been known to interact various membrane receptors with their N-terminal segments designated the PDZ domains and to cluster these receptors at the target site of the cell membrane. NE-dlg/SAP102, a neuronal and endocrine tissue-specific MAGUK family protein, was found to be expressed in both dendrites and cell bodies in neuronal cells. Although NE-dlg/SAP102 localized at dendrites was shown to interact with N-methyl-D-aspartate receptor 2B via the PDZ domains to compose postsynaptic density, the binding proteins existing in the cell body of the neuron are still unknown. Here we report the isolation of a novel NE-dlg/SAP102-associated protein, p51-nedasin. Nedasin has a significant homology with amidohydrolase superfamily proteins and shows identical sequences to a recently identified protein that has guanine aminohydrolase activity. Nedasin has four alternative splice variants (S, V1, V2, and V3) that exhibited different C-terminal structures. NE-dlg/SAP102 is shown to interact with only the S form of nedasin which is predominantly expressed in brain. The expression of nedasin in neuronal cells increases in parallel with the progress of synaptogenesis and is mainly detected in cell bodies where it co-localizes with NE-dlg/SAP102. Furthermore, nedasin interferes with the association between NE-dlg/SAP102 and NMDA receptor 2B in vitro. These findings suggest that alternative splicing of nedasin may play a role in the formation and/or structural change in synapses during neuronal development by modifying clustering of neurotransmitter receptors at the synaptic sites.

Nonbacterial prostatitis caused by partial urethral obstruction in the rat

The pathogenesis of nonbacterial prostatitis (NBP) is not understood mainly due to the lack of appropriate experimental models. We developed a new experimental model of NBP by inducing a partial obstruction of the urethra (PUO) in the rat. Male Wistar rats aged 12 weeks were used. PUO was produced by a nylon ligature on the urethra over a rubber tube. The tube was slipped out after the ligature had been tied. Two rats were examined histologically 6 h, 1 day, 3 days and 7 days after PUO. In another group, two rats were killed at 1, 3 and 7 days after the release of the PUO that had been left in place for 3 days. On day 3, another eight rats with PUO and eight control rats had 2 ml of urine in the bladder replaced by the same volume of lucifer yellow (LY; 10 microg/ml, MW 500), microperoxidase (MP; 20 microg/ml, MW 1900), horseradish peroxidase (HRP; 10 microg/ml, MW 40 000), or saline as control, respectively. Lymphocytic infiltration and interstitial edema were noted in the prostate following PUO, being most prominent on day 3. After the release of the PUO, these inflammatory changes gradually disappeared. Only LY was noted within the prostatic stroma of the rats 2 h after bladder instillation. Intraprostatic urinary reflux may be an etiologic factor in NBP. The present study showed that lower urinary tract obstruction caused NBP in the rat. Penetration of prostatic tissue by low-molecular-weight substances in the urine may trigger NBP.

Anti-granulocyte antibody screening with extracted granulocyte antigens by a micro-mixed passive hemagglutination method

BACKGROUND AND OBJECTIVES

Serologic tests for granulocyte antibodies, i.e., the granulocyte agglutination test and the granulocyte immunofluorescence test, require panels of typed granulocytes that cannot be preserved for more than a few hours. We have developed a new method in which granulocyte antigens, extracted into saline containing 3% sucrose, are coated onto U-type Terasaki plates. With this new method, we evaluated the micro-mixed passive hemagglutination test (EG-MPHA) for screening for granulocyte antibodies.

MATERIALS AND METHODS

We tested the ability of the EG-MPHA to detect granulocyte antigens using 5 human antibodies specific for NA1, NA2, NB1, 5b, and Sar(a), and 8 different monoclonal antibodies for NA1, CD11a, CD11b, CD13, CD16, CD18 and HLA class I. Sera from 94 alloimmunized patients were screened by the chloroquine-treated EG-MPHA method.

RESULTS

NA1, NA2, NB1, 5b, Sar(a), CD11a, CD11b, CD13, CD16, CD18 and HLA class I antigens were present in the extracted granulocyte antigen preparation. CD11b and HLA class I antigens were removed when the extracted granulocyte antigens were treated with chloroquine. Granulocyte antibody screening of sera from alloimmunized patients showed that approximately 30% of the anti-HLA-positive and 10% of the anti-HLA-negative sera were positive for granulocyte antibody by the chloroquine-treated EG-MPHA. The extracted granulocyte antigen panels could be stored frozen for at least 1 year at -80 degrees C.

CONCLUSION

This new method is preferable for screening for granulocyte antibodies. In addition, it has the advantage of requiring only 5 microl of serum for each test.

Autoantibody against N(epsilon)-(carboxymethyl)lysine: an advanced glycation end product of the Maillard reaction

Prolonged incubation of proteins with reducing sugar produces advanced glycation end products (AGEs), which are implicated as factors for aging and diabetic complications. We previously demonstrated the presence of N(epsilon)-(carboxymethyl)lysine (CML), one of the main AGE structures, in human and animal tissues using a monoclonal anti-CML antibody (6D12). These findings suggest that CML structures present in vivo could serve as immunogens to generate autoantibodies. This suggestion was tested in the present study. First, plasma samples from diabetic rats reacted positively with AGE bovine serum albumin (BSA). These reactivities increased with the duration of diabetic states and were inhibited specifically by CML-BSA. Second, a fraction purified from plasma of diabetic patients, which bound to AGE-BSA, showed a positive reaction to CML-BSA and furthermore also to human lens proteins, which are known to undergo CML modification in vivo. Finally, patients with renal failure caused by diabetes or nondiabetic pathologies had a higher autoantibody activity against CML structure than that in normal subjects or diabetic patients without renal failure. These results indicate that CML accumulated in vivo serves as an immunological epitope to generate an autoantibody specific for CML that might be used as a potential marker for diabetic nephropathy or chronic renal failure.

Perioperative fractionated high-dose rate brachytherapy for malignant bone and soft tissue tumors

PURPOSE

To investigate the viability of perioperative fractionated HDR brachytherapy for malignant bone and soft tissue tumors, analyzing the influence of surgical margin.

METHODS AND MATERIALS

From July 1992 through May 1996, 16 lesions of 14 patients with malignant bone and soft tissue tumors (3 liposarcomas, 3 MFHs, 2 malignant schwannomas, 2 chordomas, 1 osteosarcoma, 1 leiomyosarcoma, 1 epithelioid sarcoma, and 1 synovial sarcoma) were treated at the Osaka University Hospital. The patients' ages ranged from 14 to 72 years (median: 39 years). Treatment sites were the pelvis in 6 lesions, the upper limbs in 5, the neck in 4, and a lower limb in 1. The resection margins were classified as intracapsular in 5 lesions, marginal in 5, and wide in 6. Postoperative fractionated HDR brachytherapy was started on the 4th-13th day after surgery (median: 6th day). The total dose was 40-50 Gy/7-10 fr/4-7 day (bid) at 5 or 10 mm from the source. Follow-up periods were between 19 and 46 months (median: 30 months).

RESULTS

Local control rates were 75% at 1 year and 48% in 2 years, and ultimate local control was achieved in 8 (50%) of 16 lesions. Of the 8 uncontrolled lesions, 5 (63%) had intracapsular (macroscopically positive) resection margins, and all the 8 controlled lesions (100%) had marginal (microscopically positive) or wide (negative) margins. Of the total, 3 patients died of both tumor and metastasis, 3 of metastasis alone, 1 of tumor alone, and 7 showed no evidence of disease. Peripheral nerve palsy was seen in one case after this procedure, but no infection or delayed wound healing caused by tubing or irradiation has occurred.

CONCLUSION

Perioperative fractionated HDR brachytherapy is safe, well tolerated, and applicable to marginal or wide surgical margin cases.

Press perturbation in lattice ecosystems: parity law and optimum strategy

Press perturbation, in which the reproduction rate r of a target species is altered and held at higher or lower levels, is studied by computer simulation. We apply a lattice Lotka-Volterra model to idealized ecosystems, and obtain the optimum strategy roptdefined as follows: the steady-state density of the target species takes a maximum value at r=ropt. It is found that ropttakes a finite value, and it usually locates at a phase transition point. Moreover, we find that the long-term response to applied perturbation can be significantly predicted by parity law, where the parity is defined by whether the system contains an even or odd number of species. If the parity is even (odd), the density of the target species increases (decreases) with increasing r. An evolutionary meaning of roptis discussed in connection with the origin of sexual reproduction. Copyright 1999 Academic Press.

Interaction of NE-dlg/SAP102, a neuronal and endocrine tissue-specific membrane-associated guanylate kinase protein, with calmodulin and PSD-95/SAP90. A possible regulatory role in molecular clustering at synaptic sites

NE-dlg/SAP102, a neuronal and endocrine tissue-specific membrane-associated guanylate kinase family protein, is known to bind to C-terminal ends of N-methyl-D-aspartate receptor 2B (NR2B) through its PDZ (PSD-95/Dlg/ZO-1) domains. NE-dlg/SAP102 and NR2B colocalize at synaptic sites in cultured rat hippocampal neurons, and their expressions increase in parallel with the onset of synaptogenesis. We have identified that NE-dlg/SAP102 interacts with calmodulin in a Ca2+-dependent manner. The binding site for calmodulin has been determined to lie at the putative basic alpha-helix region located around the src homology 3 (SH3) domain of NE-dlg/SAP102. Using a surface plasmon resonance measurement system, we detected specific binding of recombinant NE-dlg/SAP102 to the immobilized calmodulin with a Kd value of 44 nM. However, the binding of Ca2+/calmodulin to NE-dlg/SAP102 did not modulate the interaction between PDZ domains of NE-dlg/SAP102 and the C-terminal end of rat NR2B. We have also identified that the region near the calmodulin binding site of NE-dlg/SAP102 interacts with the GUK-like domain of PSD-95/SAP90 by two-hybrid screening. Pull down assay revealed that NE-dlg/SAP102 can interact with PSD-95/SAP90 in the presence of both Ca2+ and calmodulin. These findings suggest that the Ca2+/calmodulin modulates interaction of neuronal membrane-associated guanylate kinase proteins and regulates clustering of neurotransmitter receptors at central synapses.

A contractile activity that closes phagosomes in macrophages

Studies of Fc-mediated phagocytosis by mouse macrophages identified a contractile activity at the distal margins of forming phagosomes. Time-lapse video microscopic analysis of macrophages containing rhodamine-labeled actin and fluorescein dextran showed that actin was concentrated at the distal margins of closing phagosomes. Phagocytosis-related contractile activities were observed when one IgG-opsonized erythrocyte was engaged by two macrophages. Both cells extended pseudopodia until they met midway around the erythrocyte. It was then constricted and pulled into two phagosomes, which remained interconnected by a string of erythrocyte membrane. Butanedione monoxime, an uncompetitive inhibitor of class II and perhaps other myosins, and wortmannin and LY294002, inhibitors of phosphoinositide 3-kinase, prevented the constrictions without inhibiting the initial pseudopod extension. Immunofluorescence microscopy showed the presence of myosins IC, II, V and IXb in phagosomes. Of these, only myosin IC was concentrated around the strings connecting shared erythrocytes, suggesting that myosin IC mediates the purse-string-like contraction that closes phagosomes. The sequential processes of pseudopod extension and contraction can explain how macropinosomes and spacious phagosomes form without guidance from a particle surface.

Reward-quality dependent anticipation in rat nucleus accumbens

Single unit recording in rat nucleus accumbens (NAcc) was used to ascertain NAcc neuronal activity in mediating of reward including its anticipation. Of the 103 neurons investigated, 63% showed some response in connection with the task activity. Of these, 20 units responded during delivery of the primary reward (food and/or water) and five responded during the time period preceding reward if the reward was delayed (four to food, one to water). These result suggest that NAcc neurons responded not only to the delivery of primary reward and task inducing anticipation of reward, but also represent the difference of reward quality between food and water specifically.