Polycomb regulates circadian rhythms in Drosophila in clock neurons

Circadian rhythms are essential physiological feature for most living organisms. Previous studies have shown that epigenetic regulation plays a crucial role. There is a knowledge gap in the chromatin state of some key clock neuron clusters. In this study, we show that circadian rhythm is affected by the epigenetic regulator Polycomb (Pc) within the Drosophila clock neurons. To investigate the molecular mechanisms underlying the roles of Pc in these clock neuron clusters, we use targeted DamID (TaDa) to identify genes significantly bound by Pc in the neurons marked by C929-Gal4 (including l-LNvs cluster), R6-Gal4 (including s-LNvs cluster), R18H11-Gal4 (including DN1 cluster), and DVpdf-Gal4, pdf-Gal80 (including LNds cluster). It shows that Pc binds to the genes involved in the circadian rhythm pathways, arguing a direct role for Pc in regulating circadian rhythms through specific clock genes. This study shows the identification of Pc targets in the clock neuron clusters, providing potential resource for understanding the regulatory mechanisms of circadian rhythms by the PcG complex. Thus, this study provided an example for epigenetic regulation of adult behavior.

Analysis of sleep in individual Drosophila melanogaster reveals a self-regulatory role for cuticular hydrocarbons pheromones

It is well established that pheromones are used by insects to transmit information between individuals. However, research has revealed that individual insects can be both the sender and the receiver of some pheromonal signals. It is therefore interesting to consider whether the pheromonal state of an individual insect can exert an effect on itself. In this study, we monitored the sleep activity of single flies exhibiting a mutation that leads to pheromonal deficiency and found that cuticular hydrocarbons (CHs) exerted self-regulatory effects on the amount of sleep experienced by these flies. To identify the physiological significance of this mechanism, we compared the amounts of sleep in individual young flies and individual old flies (flies are known to sleep less as they get older) and compared this data with young and old flies exhibiting mutations that lead to CH reception defects. The differences in the amount of sleep experienced by young and old mutant flies were significantly lower than those of the control flies. Our data show that hydrocarbon signals produced by the cuticle in Drosophila can be self-perceived and regulate the amount of sleep acquired in a maturation-dependent manner.

Epigenetic regulator Stuxnet modulates octopamine effect on sleep through a Stuxnet-Polycomb-Octβ2R cascade

Sleep homeostasis is crucial for sleep regulation. The role of epigenetic regulation in sleep homeostasis is unestablished. Previous studies showed that octopamine is important for sleep homeostasis. However, the regulatory mechanism of octopamine reception in sleep is unknown. In this study, we identify an epigenetic regulatory cascade (Stuxnet-Polycomb-Octβ2R) that modulates the octopamine receptor in Drosophila. We demonstrate that stuxnet positively regulates Octβ2R through repression of Polycomb in the ellipsoid body of the adult fly brain and that Octβ2R is one of the major receptors mediating octopamine function in sleep homeostasis. In response to octopamine, Octβ2R transcription is inhibited as a result of stuxnet downregulation. This feedback through the Stuxnet-Polycomb-Octβ2R cascade is crucial for sleep homeostasis regulation. This study demonstrates a Stuxnet-Polycomb-Octβ2R-mediated epigenetic regulatory mechanism for octopamine reception, thus providing an example of epigenetic regulation of sleep homeostasis.

Regulatory mechanism of daily sleep by miR-276a

MiRNAs have attracted more attention in recent years as regulators of sleep and circadian rhythms after their roles in circadian rhythm and sleep were discovered. In this study, we explored the roles of the miR-276a on daily sleep in Drosophila melanogaster, and found a regulatory cycle for the miR-276a pathway, in which miR-276a, regulated by the core CLOCK/CYCLE (CLK/CYC) transcription factor upstream, regulates sleep via suppressing targets TIM and NPFR1. (a) Loss of miR-276a function makes the flies sleep more during both daytime and nighttime, while flies with gain of miR-276a function sleep less; (b) MiR-276a is widely expressed in the mushroom body (MB), the pars intercerebralis (PI) and some clock neurons lateral dorsal neurons (LNds), in which tim neurons is important for sleep regulation; (c) MiR-276a promoter is identified to locate in the 8th fragment (aFrag8) of the pre-miR-276a, and this fragment is directly activated and regulated by CLK/CYC; (4) MiR-276a is rhythmically oscillating in heads of the wild-type w¹¹¹⁸ , but this oscillation disappears in the loss of function mutant clk^jrk ; (5) The neuropeptide F receptor 1 (npfr1) was found to be a downstream target of miR-276a. These results clarify that the miR-276a is a very important factor for sleep regulation.

Extra sex combs buffers sleep-related stresses through regulating Heat shock proteins

The impact of global warming on the life of the earth is increasingly concerned. Previous studies indicated that temperature changes have a serious impact on insect sleep. Sleep is critical for animals as it has many important physiological functions. It is of great significance to study the regulation mechanism of temperature-induced sleep changes for understanding the impact of global warming on insects. More importantly, understanding how these pressures regulate sleep can provide insights into improving sleep. In this study, we found that extra sex combs (ESC) are a regulatory factor in this process. Our data showed that ESC was an upstream negative regulatory factor of Heat shock proteins (Hsps), and it could regulate sleep in mushroom and ellipsoid of Drosophila. ESC mutation exaggerates the sleep change caused by temperature, while buffering the shortening of life caused by sleep deprivation. These phenotypes can be rescued by Hsps mutants. Therefore, we concluded that the ESC buffers sleep-related stresses through regulating Hsps.

Regulation of circadian rhythm and sleep by miR-375-timeless interaction in Drosophila

MicroRNAs are important coordinators of circadian regulation that mediate the fine-tuning of gene expression. Although many studies have shown the effects of individual miRNAs on the circadian clock, the global functional miRNA-mRNA interaction network involved in the circadian system remains poorly understood. Here, we used CLEAR (Covalent Ligation of Endogenous Argonaute-bound RNAs)-CLIP (Cross-Linking and Immuno-Precipitation) to explore the regulatory functions of miRNAs in the circadian system by comparing the miRNA-mRNA interactions between Drosophila wild-type strain W¹¹¹⁸ and a mutant of the key circadian transcriptional regulator Clock (Clk^jrk ). This experimental approach unambiguously identified tens of thousands of miRNA-mRNA interactions in both the head and body. The miRNA-mRNA interactome showed dramatic changes in the Clk^jrk flies. Particularly, among ~300 miRNA-mRNA circadian relevant interactions, multiple interactions involving core clock genes pdp1, tim, and vri displayed distinct changes as a result of the Clk mutation. Based on the CLEAR-CLIP analysis, we found a novel regulation of the circadian rhythm and sleep by the miR-375-timeless interaction. The results indicated that Clk disruption abolished normal rhythmic expression of miR-375 and the functional regulation occurred in the l-LNv neurons, where miR-375 modulated the circadian rhythm and sleep via targeting timeless. This work provides the first global view of miRNA regulation in the circadian rhythm.

Multi-messenger nanoprobes of hidden magnetism in a strained manganite

The ground-state properties of correlated electron systems can be extraordinarily sensitive to external stimuli, offering abundant platforms for functional materials. Using the multi-messenger combination of atomic force microscopy, cryogenic scanning near-field optical microscopy, magnetic force microscopy and ultrafast laser excitation, we demonstrate both 'writing' and 'erasing' of a metastable ferromagnetic metal phase in strained films of La_2/3Ca_1/3MnO₃ (LCMO) with nanometre-resolved finesse. By tracking both optical conductivity and magnetism at the nanoscale, we reveal how strain-coupling underlies the dynamic growth, spontaneous nanotexture and first-order melting transition of this hidden photoinduced metal. Our first-principles calculations reveal that epitaxially engineered Jahn-Teller distortion can stabilize nearly degenerate antiferromagnetic insulator and ferromagnetic metal phases. We propose a Ginzburg-Landau description to rationalize the co-active interplay of strain, lattice distortions and magnetism nano-resolved here in strained LCMO, thus guiding future functional engineering of epitaxial oxides into the regime of phase-programmable materials.

Diurnal protein oscillation profiles in Drosophila head

Circadian clocks control daily rhythms in physiology, metabolism and behaviour in most organisms. Proteome-wide analysis of protein oscillations is still lacking in Drosophila. In this study, the total protein and phosphorylated protein in Drosophila heads in a 24-h daily time-course were assayed by using the isobaric tags for relative and absolute quantitation (iTRAQ) method, and 10 and 7 oscillating proteins as well as 19 and 22 oscillating phosphoproteins in the w¹¹¹⁸ control and Clk^Jrk mutant strains were separately identified. Lastly, we performed a mini screen to investigate the functions of some oscillating proteins in circadian locomotion rhythms. This study provides the first proteomic profiling of diurnally oscillating proteins in fly heads, thereby providing a basis for further mechanistic studies of these proteins in circadian rhythm.

Anomalous phase behavior of first-order fluid-liquid phase transition in phosphorus

Although the existence of liquid-liquid phase transition has become more and more convincing, whether it will terminate at a critical point and what is the order parameter are still open. To explore these questions, we revisit the fluid-liquid phase transition (FLPT) in phosphorus (P) and study its phase behavior by performing extensive first-principles molecular dynamics simulations. The FLPT observed in experiments is well reproduced, and a fluid-liquid critical point (FLCP) at T = 3000 ∼ 3500 K, P = 1.5-2.0 Kbar is found. With decreasing temperature from the FLCP along the transition line, the density difference (Δρ) between two coexisting phases first increases from zero and then anomalously decreases; however, the entropy difference (ΔS) continuously increases from zero. These features suggest that an order parameter containing contributions from both the density and the entropy is needed to describe the FLPT in P, and at least at low temperatures, the entropy, instead of the density, governs the FLPT.

MeCP2, a target of miR-638, facilitates gastric cancer cell proliferation through activation of the MEK1/2-ERK1/2 signaling pathway by upregulating GIT1

Methyl-CpG binding protein 2 (MeCP2) is involved in the carcinogenesis and progression of multiple types of cancer. However, its precise role in gastric cancer (GC) and the relevant molecular mechanism remain unknown. In the present study, we found that miR-638 levels were lower in GC tissues and GC cell lines than in adjacent normal tissues and normal gastric epithelial cell lines, respectively. Low miR-638 levels were associated with poor tumor differentiation, tumor size and lymph node metastasis. MeCP2 expression levels were higher in GC tissues than in adjacent normal tissues. It was found that miR-638 inhibited GC cell proliferation, colony formation, G1–S transition and tumor growth, and induced cell apoptosis by directly targeting MeCP2. MeCP2 promoted GC cell proliferation, colony formation and G1–S cell-cycle transition, and suppressed apoptosis. Molecular mechanistic investigations were performed using an integrated approach with a combination of microarray analysis, chromatin immunoprecipitation sequencing and a reporter gene assay. The results showed that MeCP2 bound to the methylated CpG islands of G-protein-coupled receptor kinase-interacting protein 1 (GIT1) promoter and upregulated its expression, thereby activating the MEK1/2–ERK1/2 signaling pathway and promoting GC cell proliferation. Taken together, our study demonstrates that MeCP2, a target of miR-638, facilitates GC cell proliferation and induces cell-cycle progression through activation of the MEK1/2–ERK1/2 signaling pathway by upregulating GIT1. The findings suggest that MeCP2 plays a significant role in GC progression, and may serve as a potential target for GC therapy.

Magnetization reversal and magnetic interactions in anisotropic Nd-Dy-Fe-Co-B/MgO/α-Fe disks and multilayers

We report on a field induced domain evolutionary procedure in the anisotropic Nd-Dy-Fe-Co-B/MgO/Fe multilayers by using first-order-reversal-curves and magnetic force microscopy. Different reversal behaviors and domain sizes are found in well coupled and decoupled multilayers by changing the thickness of the spacer layer. The competition between dipolar magnetostatic energy and Zeeman energy is evaluated by in-field observation throughout nucleation and annihilation processes. In addition, lithography-patterned arrays of soft Fe disks onto a continuous Nd-Dy-Fe-Co-B hard-magnetic layer are designed. By decreasing the applied field, it is found that magnetization orientations of the Fe disk and Nd-Dy-Fe-Co-B layer are aligned parallel. In the decoupled disk, although the out-of-plane magnetization orientations are observed, the orientation of the domains in the Fe disk is random. Furthermore, it is found that a stronger anisotropy of the Nd-Dy-Fe-Co-B layer decreases the interaction length. Our results provide a new understanding of anisotropic nanocomposite magnets with long-ranged magnetic interactions.

Modeling and simulation approach to support dosing and study design requirements for treating HIV-related neuropsychiatric disease with the NK1-R antagonist aprepitant

Psychiatric illness is common in HIV-infected patients and underlines the importance for screening not only for cognitive impairment but also for co-morbid mental disease. The rationale for combining immunomodulatory neurokinin- 1 receptor (NK1-R) antagonists with combined antiretroviral therapy (cART) is based on multimodal pharmacologic mechanisms. The NK1-R antagonist aprepitant's potential utility as a drug for depression is complicated by >99.9% protein binding and both enzyme inhibition and induction of CYP3A4. A population-based PK model developed from a pilot Phase 1B trial in 19 HIV-infected patients (125 or 250 mg/d aprepitant for 2 weeks) was modified to account for enzyme induction and impact of an exposure enhancer on CYP3A4 metabolism. Likelihood of clinical success in depression was assessed based on achievement of target trough plasma concentration and evaluated using Monte Carlo simulation. Scenarios were generated for varying daily dose (375, 625, 750 and 875 mg), pharmacokinetic variability, exposure enhancement (EE), duration (2 and 6 months) and sample size (n=12 and 24/arm). Daily dosing of ≥ 625 mg with EE yielded desirable troughs (based on in vitro infectivity experiments) of > 2.65 ug/mL for the majority of virtual patients simulated. Results are dependent on the degree of exposure enhancement and extent of enzyme induction. Actual threshold exposure requirements for aprepitant in HIV-associated depression are unknown though preclinical evidence supports trough levels > 2.65 ug/mL. If 100% NK1r blockage is necessary for efficacy, doses of 875 mg (625 mg with EE) or higher may be required. The benefit of aprepitant on innate immunity(natural killer cells) and absence of negative effects onex vivo neutrophil chemotaxis alleviates concerns regarding drug dependent inhibition (DDI)-mediated infection risk.

Enhanced magnetic anisotropies of single transition-metal adatoms on a defective MoS2 monolayer

Single magnetic atoms absorbed on an atomically thin layer represent the ultimate limit of bit miniaturization for data storage. To approach the limit, a critical step is to find an appropriate material system with high chemical stability and large magnetic anisotropic energy. Here, on the basis of first-principles calculations and the spin-orbit coupling theory, it is elucidated that the transition-metal Mn and Fe atoms absorbed on disulfur vacancies of MoS₂ monolayers are very promising candidates. It is analysed that these absorption systems are of not only high chemical stabilities but also much enhanced magnetic anisotropies and particularly the easy magnetization axis is changed from the in-plane one for Mn to the out-of-plane one for Fe by a symmetry-lowering Jahn-Teller distortion. The results point out a promising direction to achieve the ultimate goal of single adatomic magnets with utilizing the defective atomically thin layers.

MECP2 promotes cell proliferation by activating ERK1/2 and inhibiting p38 activity in human hepatocellular carcinoma HEPG2 cells

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide and currently represents the leading cause of death amongst cirrhotic patients, but the mechanisms remain unknown. In this experiment, we investigated the expression of Methyl CpG-binding protein 2 (MeCP2) in HCC, the effect of MeCP2 on the proliferation of human HCC HepG2 cells, and the activation of mitogen-activated protein kinases (MAPKs) signaling pathways. The results showed that MeCP2 expression levels was higher in human HCC tissue than normal hepatocellular tissue, and MeCP2 siRNA reduced the proliferation of HCC HepG2 cells by decreasing cell activity and cell division in vitro. After MeCP2 siRNA treatment, the proportion of G1/G0 phase cells increased, but the proportion of S and G2/M phase cells decreased, indicative of G1/G0 cell cycle arrest. Furthermore, the proportions of early and late apoptosis in HCC HepG2 cells were enhanced after MeCP2 siRNA treatment. It was also found that activation of extracellular signal-regulated protein kinase (ERK) and p38 signaling pathways were involved in the proliferation of HepG2 cells. After MeCP2 siRNA treatment, p-ERK1/2 levels decreased, but p-p38 levels increased. Our findings demonstrated that MeCP2 promoted the proliferation of human HCC HepG2 cells with activation of ERK1/2 signaling pathways, suggesting a novel mechanism for pharmacological study of treatment for human HCC.

AUC-based biomarker ensemble with an application on gene scores predicting low bone mineral density

MOTIVATION

The area under the receiver operating characteristic (ROC) curve (AUC), long regarded as a 'golden' measure for the predictiveness of a continuous score, has propelled the need to develop AUC-based predictors. However, the AUC-based ensemble methods are rather scant, largely due to the fact that the associated objective function is neither continuous nor concave. Indeed, there is no reliable numerical algorithm identifying optimal combination of a set of biomarkers to maximize the AUC, especially when the number of biomarkers is large.

RESULTS

We have proposed a novel AUC-based statistical ensemble methods for combining multiple biomarkers to differentiate a binary response of interest. Specifically, we propose to replace the non-continuous and non-convex AUC objective function by a convex surrogate loss function, whose minimizer can be efficiently identified. With the established framework, the lasso and other regularization techniques enable feature selections. Extensive simulations have demonstrated the superiority of the new methods to the existing methods. The proposal has been applied to a gene expression dataset to construct gene expression scores to differentiate elderly women with low bone mineral density (BMD) and those with normal BMD. The AUCs of the resulting scores in the independent test dataset has been satisfactory.

CONCLUSION

Aiming for directly maximizing AUC, the proposed AUC-based ensemble method provides an efficient means of generating a stable combination of multiple biomarkers, which is especially useful under the high-dimensional settings.

CONTACT

lutian@stanford.edu.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Identifying rodent olfactory bulb structures with micro-DTI

Olfactory bulb (OB) is one of the most developed systems in rodent models with complex neuronal organization and anatomical structures. MR diffusion tensor imaging (DTI) is a non-invasive technique to probe tissue microstructures by examining the diffusion characteristics of water molecules. This paper presents how different OB layers can be identified and quantitatively characterized by micro-DTI using a specially constructed micro-imaging radio frequency (RF) coil. High spatial resolution and high signal to noise ratio (SNR) DTI images of ex vivo rat OBs were obtained. Distinct contrasts were observed between various olfactory bulb layers in trace map, fractional anisotropy (FA) map and FA color map, all in consistency with the known OB neuroanatomy. These experimental results demonstrate the utility of micro-DTI in investigation of complex OB organization.

A sensitive and rapid liquid chromatography-tandem mass spectrometry method for the quantification of the novel neurokinin-1 receptor antagonist aprepitant in rhesus macaque plasma, and cerebral spinal fluid, and human plasma with application in translational NeuroAIDs research

A sensitive and rapid liquid chromatography-tandem mass spectrometry method has been developed for to assess therapeutic exposures of aprepitant in HIV-infected patients and rhesus macaques. The method utilized a simple sample-preparation procedure of protein precipitation with methanol. Chromatographic separation was performed on a reversed phase C(8) column (Hypersil Gold, 50 mm x 2.1 mm, 3 microm) using a mobile phase composed of acetonitrile and water in 0.5% formic acid through gradient elution. Electro-spray ionization in positive mode was incorporated in the tandem mass spectrometric detection. The lower limit of quantitation of aprepitant in plasma of rhesus macaques and human and cerebral spinal fluid of rhesus macaques were 1, 1, and 0.1 ng/mL, respectively. The method has been successfully employed to measure aprepitant in preclinical and clinical samples collected from three SIV-infected rhesus macaques and ten patients with HIV infection. In conclusion, this liquid chromatography-tandem mass spectrometry method is suitable for preclinical-clinical translational research exploring exposure-response relationships with aprepitant as well as therapeutic drug monitoring of aprepitant.

In vivo tumor detection on rabbit with biopsy needle as MRE driver

Magnetic Resonance Elastography (MRE) is a phase contrast imaging technique to quantitatively measure the elasticity of tissues. Typically, the oscillating driver is placed on the surface of objects to generate shear waves. When it is applied to detect tumors in deep location, the depth penetration of the wave is limited by attenuation and the biopsy procedure has to be performed separately. In this study, we describe a method using biopsy needle as the MRE driver to produce shear waves in tissues. We made comparison between the MRE acquisitions obtained with biopsy needle and surface drivers. Because the well-defined propagation wave pattern reduces the error in wavelength calculation, the acquisitions of biopsy needle driver shows better homogeneity in stiffness map. We also performed the experiment with the biopsy needle for in vivo tumor detection in rabbits. This study demonstrates that the biopsy needle driver is more effective than the surface driver for accurately measuring the stiffness and location of the tumor.

Biopsy needle as MRE driver for tumor detection

Magnetic Resonance Elastography (MRE) is a phase contrast imaging technique to quantitatively measure the elasticity of tissues. Typically, an oscillating driver is placed on the surface to generate the shear waves. The depth penetration of the wave is limited by attenuation and the biopsy procedure has to be done separately. In this study, we use a biopsy needle as the driver to detect the 15% porcine gel inclusion in a 10% porcine gel phantom which simulates a tumor in tissues. We also perform the experiment with the biopsy needle for in-vivo tumor detection in rabbits. It is shown that the biopsy needle driver can accurately measure the stiffness and location of the tumor.

Effects of dietary methionine and lysine sources on nutrient digestion, nitrogen utilization, and duodenal amino acid flow in growing goats

This study investigated the effects of supplementation of various sources of Met and Lys on nutrient digestion, N utilization, and duodenal AA flows in growing goats. Four 4-mo-old Liuyang Black wether goats were used in a 4 x 4 Latin square experiment and were assigned to 4 dietary treatments: (1) control, (2) control + lipid-coated Met-Zn chelate and Lys-Mn chelate (PML), (3) control + Met-Zn chelate and Lys-Mn chelate (CML), and (4) control + dl-Met, l-Lys-HCl, ZnSO(4).7H(2)O, and MnSO(4).H(2)O (FML). Compared with control, PML reduced (P < 0.05) ruminal NH(3) concentration, urinary N excretion, and plasma urea N concentration and increased (P < 0.05) the activity of ruminal endo-1,4-beta-d-glucanase and beta-glucosidase, the duodenal flow of N, N retention (g/d as well as % of absorbed N), the duodenal flows of Met, Lys, His, Val, and total essential AA, and plasma concentrations of Lys, Val, Phe, and total essential AA. Supplementing Zn-Met and Mn-Lys chelates had similar (P > 0.05) but lesser effects on these measures compared with PML, and the effects on most of the measures were not statistically significant (P > 0.05) when compared with control. Supplementing free-form Met and Lys had no effects compared with control (P > 0.05). The results indicate that lipid coating and chelating of AA provide a protection, and to a lesser extent by only chelating, of the AA from microbial degradation in the rumen and possibly has effects on rumen fermentation, which increases MP supply. This technology could improve productive performance and be of potential benefit to ruminant production if cost-effective products are developed.

Comparative in vitro metabolism of 14C-ciclesonide in hepatocytes from the mouse, rat, rabbit, dog, and human

The in vitro metabolism of ciclesonide, a novel inhaled nonhalogenated glucocorticoid for the treatment of asthma, was compared in cryopreserved hepatocytes from mice, rats, rabbits, dogs, and humans. Incubations of C-ciclesonide with individual hepatocyte suspensions revealed similar metabolite profiles in all 5 in vitro systems used. Ciclesonide was rapidly converted to its active metabolite, desisobutyryl-ciclesonide (des-CIC). Des-CIC was then extensively metabolized to pharmacologically inactive metabolites through oxidation and reduction, followed by glucuronidation. A total of 12 groups of metabolites derived from des-CIC were characterized and identified by liquid chromatography/radioactivity monitor/mass spectrometry. Oxidation occurred on both the cyclohexane ring and the steroid moiety. Hippuric acid formation by cleavage of the cyclohexylmethyl moiety of ciclesonide, followed by aromatization of the cyclohexane ring through multiple steps of hydroxylation, dehydration, and conjugation with glycine, was found in rat, rabbit, and human hepatocyte incubations. The results indicated that ciclesonide and its active metabolite, des-CIC, were extensively metabolized in vitro in animal and human hepatocytes and that the metabolite profiles in mouse, rat, rabbit, and dog hepatocytes were similar to the profiles in human hepatocytes.

[Improvement of suture technique for arteriovenous fistula]

OBJECTIVE

To investigate the clinical effect of continuous suture technique for closure of surgically created arteriovenous fistulas at different sites.

METHOD

A total of 160 patients with chronic renal failure underwent surgery to create arteriovenous fistulas at different sites, which were closed with continuous suture technique.

RESULTS

The time for vessel anastomosis was reduced with this suture technique, and the success rate of anastomosis at one time and the overall operative success rate were improved, with also reduction of complications to achieve satisfactory clinical results.

CONCLUSION

Continuous suture technique well suits the demand in anastomosis of arteriovenous fistula at different sites, especially in cases with poor vascular condition.

[Transfection of human umbilical vein endothelial cell line ECV-304 with liposome-oligonucleotide complexes under hypothermic and anoxic conditions]

OBJECTIVE

To investigate the transfection efficiency of nuclear factor (NF)-kappaB decoy oligodeoxynucleotides (ODN) mediated by in vivo liposome in human umbilical vascular endothelial cell line ECV-304 under hypothermic and anoxic conditions.

METHODS

ECV-304 cells were cultured in RPMI 1640 culture medium containing 10% fetal bovine serum at 37 degrees Celsius; in the presence of 5% CO2. Liposome-ODN complexes were prepared just before use and added to the cells with a liposome-ODN charge ratio of 2:1. ECV-304 cell monolayers were transfected with liposome-ODN complexes containing 0.50, 0.75, 1.00 and 1.25 micromol/L ODN respectively in Euro-Collins solution (ECs) at 4 degrees celsius; and then stored for 2, 4, 6 and 8 hours respectively under anoxic condition. The ODN without liposome was transfected into ECV-304 cells under identical conditions as the control. The distribution of fluorescein isothiocyanate (FITC)-labeled ODN in ECV-304 cells was observed by fluorescence microscope, and the transfection efficiency and mean fluorescence intensity (MFI) were evaluated by flow cytometry.

RESULTS

MFI was enhanced as the storage time extended and ODN concentration increased, reaching the peak level at 6 h (P<0.05). After a 6-hour storage, most of the ODN was found to locate in the cell nuclei, and the transfection efficiency did not vary significantly between the groups. Compared with the control group, however, the differences in transfection efficiency and MFI were significant.

CONCLUSION

ODN can be highly efficiently transfected into ECV-304 cells by in vivo liposome in ECs under hypothermic and anoxic conditions, which provides an experimental basis for further study of the donor organ preservation at the level of genetic regulation.

High-level production of alpha-particle-emitting (211)At and preparation of (211)At-labeled antibodies for clinical use

In vitro and in vivo studies in human glioma models suggest that the antitenascin monoclonal antibody 81C6 labeled with the 7.2-h-half-life alpha-particle emitter (211)At might be a valuable endoradiotherapeutic agent for the treatment of brain tumors. The purpose of this study was to develop methods for the production of high levels of (211)At and the radiosynthesis of clinically useful amounts of (211)At-labeled human/mouse chimeric 81C6 antibody.

METHODS

(211)At was produced through the (209)Bi(alpha, 2n)(211)At reaction using an internal target system and purified by a dry distillation process. Antibody labeling was accomplished by first synthesizing N-succinimidyl 3-[(211)At]astatobenzoate from the corresponding tri-n-butyl tin precursor and reacting it with the antibody in pH 8.5 borate buffer. Quality control procedures consisted of methanol precipitation, size-exclusion high-performance liquid chromatography (HPLC), and pyrogen and sterility assays, as well as determination of the immunoreactive fraction by a rapid procedure using a recombinant tenascin fragment coupled to magnetic beads.

RESULTS

A total of 16 antibody labeling runs were performed. Using beam currents of 50-60 microA alpha-particles and irradiation times of 1.5-4.5 h, the mean (211)At production yield was 27.75 +/- 2.59 MBq/microA.h, and the maximum level of (211)At produced was 6.59 GBq after a 4-h irradiation at 55 microA. The decay-corrected distillation yield was 67% +/- 16%. The yield for the coupling of the (211)At-labeled active ester to the antibody was 76% +/- 8%. The fraction of (211)At activity that eluted with a retention time corresponding to intact IgG on HPLC was 96.0% +/- 2.5%. All preparations had a pyrogen level of <0.125 EU/mL and were determined to be sterile. The mean immunoreactive fraction for these 16 preparations was 83.3% +/- 5.3%. Radiolysis did not interfere with labeling chemistry or the quality of the labeled antibody product.

CONCLUSION

These results show that it is feasible to produce clinically relevant activities of (211)At-labeled antibodies and have permitted the initiation of a phase I trial of (211)At-labeled chimeric 81C6 administered directly into the tumor resection cavities of brain tumor patients.

Synthesis, characterization, and magnetic properties of carbon- and boron-oxide-encapsulated iron nanocapsules

Carbon- and boron-oxide-encapsulated iron nanocapsules have been synthesized by arc discharge in methane (CH4) and diborane (B2H6) atmospheres respectively. The characterization and magnetic properties of carbon- and boron-oxide-encapsulated iron nanocapsules [abbreviated as Fe(C) and Fe(B) respectively] were investigated and compared. The structure of the Fe(B) nanocapsules is different from that of the Fe(C) nanocapsules. The Fe(C) nanocapsules consist of a crystalline graphite shell and a core of alpha-Fe and/or Fe3C. The Fe(B) nanocapsules consist of an amorphous boron-oxide layer and a core of Fe(B) solid solution, alpha-Fe, gamma-Fe, FeB, and/or Fe3B phases. The saturation magnetizations of both the Fe(C) and the Fe(B) nanocapsules below 300 K decrease monotonically with increasing temperature. The coercivities of the Fe(C) and Fe(B) nanocapsules are almost 2 orders of magnitude higher than that of bulk Fe. The temperature dependence of magnetization at high temperatures indicates the existence of some phase transformations.

Phase I trial results of iodine-131-labeled antitenascin monoclonal antibody 81C6 treatment of patients with newly diagnosed malignant gliomas

PURPOSE

To determine the maximum-tolerated dose (MTD) of iodine-131 ((131)I)-labeled 81C6 antitenascin monoclonal antibody (mAb) administered clinically into surgically created resection cavities (SCRCs) in malignant glioma patients and to identify any objective responses with this treatment.

PATIENTS AND METHODS

In this phase I trial, newly diagnosed patients with malignant gliomas with no prior external-beam therapy or chemotherapy were treated with a single injection of (131)I-labeled 81C6 through a Rickham reservoir into the resection cavity. The initial dose was 20 mCi and escalation was in 20-mCi increments. Patients were observed for toxicity and response until death or for a minimum of 1 year after treatment.

RESULTS

We treated 42 patients with (131)I-labeled 81C6 mAb in administered doses up to 180 mCi. Dose-limiting toxicity was observed at doses greater than 120 mCi and consisted of delayed neurotoxicity. None of the patients developed major hematologic toxicity. Median survival for patients with glioblastoma multiforme and for all patients was 69 and 79 weeks, respectively.

CONCLUSION

The MTD for administration of (131)I-labeled 81C6 into the SCRC of newly diagnosed patients with no prior radiation therapy or chemotherapy was 120 mCi. Dose-limiting toxicity was delayed neurologic toxicity. We are encouraged by the survival and toxicity and by the low 2.5% prevalence of debulking surgery for symptomatic radiation necrosis.

Characterization of two structural forms of otonecine-type pyrrolizidine alkaloids from Ligularia hodgsonii by NMR spectroscopy

Clivorine (1) and ligularine (2), two hepatotoxic otonecine-type pyrrolizidine alkaloids isolated from Ligularia hodgsonii, an antitussive traditional Chinese medicine, were investigated in CDCl(3) and D(2)O by various NMR techniques to delineate why this type of alkaloid displays uncharacteristic solubility properties by dissolving in both nonpolar organic and aqueous solutions. The results demonstrated that both alkaloids exist in a non-ionized form in CDCl(3), but in an ionized form in D(2)O, suggesting that this unique dual solubility may play a role in the intoxication resultant from consumption of water extracts of herbs, including herbal teas, containing otonecine-type pyrrolizidine alkaloids.

Dosimetry and dose-response relationships in newly diagnosed patients with malignant gliomas treated with iodine-131-labeled anti-tenascin monoclonal antibody 81C6 therapy

PURPOSE

The objective of this study was to perform the dosimetry and evaluate the dose-response relationships in newly diagnosed patients with malignant brain tumors treated by direct injections of (131)I-labeled 81C6 monoclonal antibody (MAb) into surgically created resection cavities (SCRCs).

METHODS AND MATERIALS

Absorbed doses to the 2-cm-thick shell as measured from the margins of the resection cavity interface were estimated for 42 patients with primary brain tumors. MR images were used to assess the enhanced-rim volume as a function of time after radiolabeled MAb therapy. Biopsy samples were obtained from 15 patients and 1 autopsy.

RESULTS

The average absorbed dose [range] to the 2-cm shell region was 32 [3-59] Gy. For the endpoint of minimal time to MR contrast enhancement, the optimal absorbed dose and initial dose-rate were 43 +/- 16 Gy and 0. 41 +/- 0.10 Gy/h, respectively. There was a correlation between the absorbed dose and dose rate to the shell region and biopsy outcome (tumor recurrence, radionecrosis, and tumor recurrence and/or radionecrosis). In this Phase I study, the maximum tolerated dose (MTD) was 120 mCi. At this MTD, the estimated average absorbed dose and initial dose rate to the 2-cm shell were 41 [9-89] Gy and 0.51 [0.24-1.13] Gy/h, respectively. These values are in agreement with the optimal values based on the time to MR lesion rim enhancement.

CONCLUSIONS

The average absorbed dose to the 2-cm shell region varied considerably and mainly depended on cavity volume. In future clinical trials, the administered activity of (131)I-labeled 81C6 MAb may be adjusted based on cavity volume in order to deliver the optimal absorbed dose of 43 Gy rather than giving a fixed administered activity.

Radioiodinated antibody targeting of the HER-2/neu oncoprotein: effects of labeling method on cellular processing and tissue distribution

Monoclonal antibody (MAb) internalization can have a major effect on tumor retention of radiolabel. Two anti-HER-2/neu MAbs (TA1 and 520C9) were radioiodinated using the iodogen, N-succinimidyl 5-iodo-3-pyridinecarboxylate (SIPC), and tyramine-cellobiose (TCB) methods. Paired-label studies compared internalization and cellular processing of the labeled MAbs by SKOv3 9002-18 ovarian cancer cells in vitro. Intracellular radioiodine activity for 520C9 was up to 2.6 and 3.0 times higher for SIPC and TCB labeling, respectively, compared with iodogen. Likewise, intracellular activity for TA1 was up to 2.3 and 2.9 times higher with the SIPC and TCB methods compared with iodogen labeling. Unfortunately, similar advantages in tumor accumulation were not achieved in athymic mice bearing SKOv3 9008-18 ovarian cancer xenografts.

Dosimetry of 131I-labeled 81C6 monoclonal antibody administered into surgically created resection cavities in patients with malignant brain tumors

The objective of this study was to perform the dosimetry of 131I-labeled 81C6 monoclonal antibody (MAb) in patients with recurrent malignant brain tumors, treated by direct injections of MAb into surgically created resection cavities (SCRCs).

METHODS

Absorbed dose estimates were performed for nine patients. Dosimetry was performed retrospectively using probe counts (during patient isolation) and whole-body and SPECT images thereafter. Absorbed doses were calculated for the SCRC interface and for regions of interest (ROIs) 1 and 2 cm thick, measured from the margins of cavity interface. Also, mean absorbed doses were calculated for normal brain, liver, spleen, thyroid gland, stomach, bone marrow and whole body. The average residence time for the SCRC was 111 h (65-200h).

RESULTS

The average absorbed dose per unit injected activity (range) to the SCRC interface and ROIs 1 and 2 cm thick from the cavity interface were 31.9 (7.8-84.2), 1.9 (0.7-3.6) and 1.0 (0.4-1.8) cGy/MBq, respectively. Average absorbed doses per unit administered activity to brain, liver, spleen, thyroid, stomach, bone marrow and whole body were 0.18, 0.03, 0.08, 0.05, 0.02, 0.02 and 0.01 cGy/MBq, respectively. The high absorbed dose delivered to the SCRC interface may have produced an increase in cavity volume independent of tumor progression.

CONCLUSION

At the maximum tolerated dose of 3700 MBq 131I-labeled 81C6 MAb, the absorbed doses to the SCRC interface and ROIs of 1 and 2 cm thickness were estimated to be 1180, 71 and 39 Gy, respectively. The estimated average absorbed dose to the brain was 6.5 Gy. There was no neurological toxicity and minimal hematologic toxicity at this maximum tolerated administration level.

Iodine-131-labeled antitenascin monoclonal antibody 81C6 treatment of patients with recurrent malignant gliomas: phase I trial results

PURPOSE

To determine the maximum-tolerated dose (MTD) of iodine 131 (131I)-labeled 81C6 monoclonal antibody (mAb) in brain tumor patients with surgically created resection cavities (SCRCs) and to identify any objective responses to this treatment.

METHODS

In this phase I trial, eligible patients were treated with a single injection of 131I-labeled 81C6. Cohorts of three to six patients were treated with escalating dosages of 131I (starting dose of 20 mCi with a 20-mCi escalation in subsequent cohorts) administered through an Ommaya reservoir in the SCRC. Patients were followed up for toxicity and response until death or for a minimum of 1 year after treatment. The SCRC patients, who were previously irradiated, were followed up without additional treatment unless progressive disease was identified.

RESULTS

We administered 36 treatments of 131I doses up to 120 mCi to 34 previously irradiated patients with recurrent or metastatic brain tumors. Dose-limiting toxicity was reached at 120 mCi and was limited to neurologic or hematologic toxicity. None of the patients treated with less than 120 mCi developed significant neurologic toxicity; one patient developed major hematologic toxicity (MHT). The estimated median survival for patients with glioblastoma multiforme (GBM) and for all patients was 56 and 60 weeks, respectively.

CONCLUSION

The MTD for administration of 131I-labeled 81C6 into the SCRCs of previously irradiated patients with recurrent primary or metastatic brain tumors was 100 mCi. The dose-limiting toxicity was neurologic toxicity. We are encouraged by the minimal toxicity and survival in this phase I trial. Radiolabeled mAbs may improve the current therapy for brain tumor patients.

Determination of hepatotoxic pyrrolizidine alkaloids by on-line high performance liquid chromatography mass spectrometry with an electrospray interface

The present study describes the determination of two different types of hepatotoxic pyrrolizidine alkaloids (PAs) and also distinguishing the hepatotoxic PAs from non-toxic ones by both in-source collision-induced dissociation high performance liquid chromatography mass spectrometry (CID-HPLC/MS) and HPLC/MS/MS (CID in the collision cell), using electrospray ionization. The mass spectra provided molecular ions and characteristic fragment ions, which could be used readily for a rapid identification of different types of PAs. Applications of both in-source CID-HPLC/MS and HPLC/MS/MS analytical methods were successful for the determination of PAs in blood samples obtained from rats dosed with PAs and in the PA-containing plant. The results demonstrated that the developed HPLC/MS methods with two different CID techniques provided a very simple and rapid analysis for an unequivocal diagnosis of PA poisoning and for definitive identification of PAs in plants or herbal medicines.

Construction of a human heart cDNA library and identification of cardiovascular based genes (CVBest)

The availability of high quality cDNA libraries is often crucial to the successful identification and characterization of genes. The concepts and potential pitfalls of constructing cDNA libraries are presented. Various applications requiring high quality cDNA libraries are outlined, including large-scale single pass sequencing of cDNA clones to generate expressed sequence tags (ESTs) and differential screening of cDNA libraries. The usefulness of combining such approaches for the discovery of novel disease-related and cardiovascular-based ESTs (CVBest) is discussed.

Radioiodinated antibody targeting of the HER-2/neu oncoprotein

The HER-2/neu oncogene encodes a 185 kDa phosphoglycoprotein that is overexpressed in breast, ovarian and other cancers. Seven monoclonal antibodies reactive with oncoprotein were labeled with 131I. In vitro experiments with SKOv3 9002-18 cells determined binding affinity, internalization and degradation. The biodistribution of these antibodies in comparison to 125I-labeled nonspecific antibody was measured in athymic mice with SKOv3 9002-18 ovarian carcinoma xenografts. Antibody 520C9 exhibited the highest and most specific retention in tumor, peaking at 17.4 +/- 5.6% ID/g at 24 h.

No-carrier-added iodine-131-FIBG: evaluation of an MIBG analog

The purpose of this study was to evaluate the properties of 4-fluoro-3-[131I]iodobenzylguanidine ([131I]FIBG), a potential neuroendocrine tumor and myocardial imaging radiopharmaceutical.

METHODS

The binding of [131I]FIBG and [125I]MIBG was compared in vitro using the SK-N-SH human neuroblastoma cell line. The role of the active uptake-1 mechanism was investigated by determining the effect on cell binding of desipramine (DMI), ouabain, norepinephrine (NE), unlabeled MIBG and FIBG and by incubation at 4 degrees C. Finally, the tissue distributions of [131I]FIBG and [125I]MIBG were compared in normal mice.

RESULTS

The specific binding of [131I]FIBG remained fairly constant (45%-60%) over a 2-3-log activity range and consistently was 11%-14% higher (p < 0.05) than that of [125I]MIBG. The uptake of [131I]FIBG was reduced to 13% of control values by 1.5 microM DMI, to 31% by 1 mM ouabain, to 8% by lower temperature, to 8% by 50 microM NE and to 6% and 5% by 10 microM each of unlabeled MIBG and FIBG, respectively. The amount of [131I]FIBG retained by SK-N-SH cells was significantly higher than that of [125I]MIBG with the maximum difference observed at 72 hr. In mice, the uptake of [131I]FIBG was higher than that of [125I]MIBG not only in target tissues (heart and adrenals) but also in many other normal tissues; conversely, thyroidal uptake of [131I]FIBG was 2-3-fold lower than that of [125I]MIBG. The uptake of [131I]FIBG in the heart and adrenals was reduced by DMI.

CONCLUSION

Iodine-131-FIBG is an analog of MIBG with prolonged binding to neuroblastoma cells in vitro and retention in the myocardium in vivo.

3-[211At]astato-4-fluorobenzylguanidine: a potential therapeutic agent with prolonged retention by neuroblastoma cells

An analogue of meta-iodobenzylguanidine (MIBG) in which an aromatic hydrogen was replaced with fluorine has been found to possess many properties similar to those of the parent compound. Moreover, 4-fluoro-3-iodobenzylguanidine (FIBG) was retained in vitro by human neuroblastoma cells to a much greater extent than MIBG itself. Since alpha-emitters such as 211At could be valuable for the treatment of micrometastatic disease, an FIBG analogue in which the iodine atom is replaced by 211At would be of interest. In this study, we have evaluated the in vitro and in vivo properties of 3-[211At]astato-4-fluorobenzylguanidine ([211At]AFBG). The specific binding of [211At]AFBG to SK-N-SH human neuroblastoma cells remained fairly constant over 2- to 3-log activity range and was similar to that of [131I]MIBG. The uptake of [211At]AFBG by this cell line was reduced by desipramine, ouabain, 4 degrees C incubation, noradrenaline, unlabelled MIBG and FIBG, suggesting that its uptake is specifically mediated through an active uptake-1 mechanism. Over the 16 h period studied, the amount of [211At]AFBG retained was similar to that of [131I]FIBG, whereas the per cent of retained meta-[211At]astatobenzylguanidine ([211At]MABG) was considerably less than that of [131I]FIBG (53% vs 75%; P < 0.05). The IC50 values for the inhibition of uptake of [131I]MIBG, [211At]MABG, [125I]FIBG and [211At]AFBG by unlabelled MIBG were 209, 300, 407 and 661 nM respectively, suggesting that the affinities of these tracers for the noradrenaline transporter in SK-N-SH cells increase in that order. Compared with [211At]MABG, higher uptake of [211At]AFBG was seen in vivo in normal mouse target tissues such as heart and, to a certain extent, in adrenals. That the uptake of [211At]AFBG in these tissues was related to the uptake-1 mechanism was demonstrated by its reduction when mice were pretreated with desipramine. However, the stability of [211At]AFBG towards in vivo dehalogenation was less than that of [211At]MABG, as evidenced by the higher uptake of 211At in thyroid, spleen, lungs and stomach.

Intrathecal 131I-labeled antitenascin monoclonal antibody 81C6 treatment of patients with leptomeningeal neoplasms or primary brain tumor resection cavities with subarachnoid communication: phase I trial results

We aimed to determine the maximum tolerated dose (MTD) of 131I-labeled 81C6 in patients with leptomeningeal neoplasms or brain tumor resection cavities with subarachnoid communication and to identify any objective responses. 81C6 is a murine IgG monoclonal antibody that reacts with tenascin in gliomas/carcinomas but does not react with normal adult brain. 131I-labeled 81C6 delivers intrathecal (IT) radiation to these neoplasms. This study was a Phase I trial in which patients were treated with a single IT dose of 131I-labeled 81C6. Cohorts of three to six patients were treated with escalating doses of 131I (starting dose, 40 mCi; 20 mCi escalations) on 10 mg 81C6. MTD is defined as the highest dose resulting in serious toxicity in no more than two of six patients. Serious toxicity is defined as grade III/IV nonhematological toxicity or major hematological toxicity. We treated 31 patients (8 pediatric and 23 adult). Eighteen had glioblastoma multiforme. Patients were treated with 131I doses from 40 to 100 mCi. Hematological toxicity was dose limiting and correlated with the administered 131I dose. No grade III/IV nonhematological toxicities were encountered. A partial response occurred in 1 patient and disease stabilization occurred in 13 (42%) of 31 patients. Twelve patients are alive (median follow-up, > 320 days); five are progression free >409 days median posttreatment. The MTD of a single IT administration of 131I-labeled 81C6 in adults is 80 mCi 131I-labeled 81C6. The MTD in pediatric patients was not reached at 131I doses up to 40 mCi normalized for body surface area.

Tumor antigens in astrocytic gliomas

Gliomas affect 15,000 to 17,000 Americans every year and carry a dismal prognosis. The potential of immunologically mediated diagnosis and therapy, although greatly enhanced since the advent of monoclonal antibodies, has not been fully realized due to significant problems, most especially the challenge of identifying antigenic molecules specific to glial tumors. Other problematic issues include antigen-associated factors such as heterogeneity, modulation, shedding, and cross-reactivity with normal cells, and factors associated with therapeutic agent delivery, typically variable tumor perfusion and unfavorable diffusional forces in tumor microenvironment. An understanding of these problems called for the delineation of operationally specific antigens (tumor-associated antigens not expressed by the normal central nervous system) combined with the use of compartmental therapeutic approaches to increase the specificity of therapy. Numerous antigens have been identified and are classified as extracellular/matrix-associated, membrane-associated, and intracellular antigens. Nevertheless, only a few have been demonstrated to be of significant therapeutic and diagnostic utility. These few include the extracellular matrix-associated antigens tenascin and GP 240, defined by the monoclonal antibodies 81C6 and Mel-14, both of which are now in Phase I clinical trials, and membrane-associated ganglioside molecules, primarily 3', 6'-isoLD1, defined by the antibody DMAb-22. Recent identification of the overexpression of a deletion variant of the epidermal growth factor receptor (EGFRvIII) in up to 50% of the more malignant glial tumors and the subsequent creation of monoclonal antibodies that are specific to this molecule and do not recognize the wild-type EGFR provide the most exciting development yet in the design of specific antiglioma immunoconjugates. In addition, the tumor-specific nature of EGFRvIII combined with improved knowledge of immune mechanisms, especially in the context of the central nervous system, will facilitate the design of highly selective cell-mediated therapeutic approaches with a view toward obtaining tumor-specific immunity.

Phase I studies of treatment of malignant gliomas and neoplastic meningitis with 131I-radiolabeled monoclonal antibodies anti-tenascin 81C6 and anti-chondroitin proteoglycan sulfate Me1-14 F (ab')2--a preliminary report

The advent of monoclonal antibody (MAb) technology has made Ehrlich's postulate of the 'magic bullet' an attainable goal. Although specific localization of polyvalent antibodies to human gliomas was demonstrated in the 1960s, the lack of specific, high affinity antibody populations and of defined target antigens of sufficient density precluded therapeutic applications. Not until the identification of operationally specific tumor-associated antigens (present in tumor tissue but not normal central nervous system tissue); production of homogeneous, high affinity MAbs to such antigens; and the use of compartmental administration (intrathecal or intracystic), has the promise of passive immunotherapy of primary and metastatic central nervous system neoplasms been recognized. We report here preliminary data from Phase I studies of the compartmental administration of the anti-tenascin MAb 81C6 and F(ab2)2 fragments of MAb Me1-14, which recognizes the proteoglycan chondroitin sulfate-associated protein of gliomas and melanomas, to patients with primary central nervous system tumors or tumors metastatic to the central nervous system. Phase I dose escalation studies of intracystically administered 131I-labeled anti-tenascin MAb 81C6 to either spontaneous cysts of recurrent gliomas or surgically created cystic resection cavities have resulted in striking responses. Of five patients with recurrent cystic gliomas treated, four had partial responses, clinically or radiographically. Similarly, in patients with surgically created resection cavities, a partial response at the treatment site and extended stable disease status has been obtained following intracystic administration of 131I-labeled 81C6. No evidence of hematologic or neurologic toxicity has been observed in either patient population, with the exception of transient exacerbation of a pre-existing seizure disorder in a single patient. Dosimetry calculations indicated high intracystic retention for four to six weeks with little or no systemic dissemination; estimated total doses intracystically ranged from 12,700-70,290 rad. Intrathecal administration of labeled MAbs to patients with neoplastic meningitis is more difficult to assess in terms of clinical responsiveness. Of patients so treated with either 131I-labeled 81C6 or 131I-labeled Me1-14 (F(ab)2, cerebrospinal fluid and radiographic responses have been achieved, and survival prolongation through maintenance of stable disease has been observed in several cases. Initial results from pHase I dose escalation trials are encouraging in terms of the proportion of cases of disease stabilization and partial and complete responses obtained. Importantly, neurotoxicity has been virtually nonexistent, and hematologic toxicity rare and rapidly responsive to treatment.(ABSTRACT TRUNCATED AT 400 WORDS)

Reconstruction of esophagus with whole stomach through esophageal bed after resection of the upper esophageal carcinoma. A report of 160 cases

From September 1985 to December 1992, 160 cases of reconstruction of the esophagus with the whole stomach through the esophageal bed after resection of the upper esophageal carcinoma were performed with neither operative mortality nor intrathoracic complications. The leakage rate of the cervical anastomosis with Gambee's single layer method was 1.2%. The main steps of the operative procedure consisted of: (1) making a right thoracotomy for dissecting and removing the entire thoracic esophagus; (2) laparotomy for mobilizing the whole stomach, constricting it to tube shape and doing a pyloroplasty; and (3) pulling up the mobilized tube-like stomach through the posterior mediastinal space (i.e. the esophageal bed) out of the left neck incision and then the esophagogastrostomy with Gambee's single layer anastomosis was performed.

Protection against carbon tetrachloride-induced hepatotoxicity by pretreating rats with the hemisuccinate esters of tocopherol and cholesterol

Previous studies have demonstrated that alpha-tocopheryl hemisuccinate (TS) protects hepatocyte suspensions from chemical-induced toxicity. It has been suggested that TS cytoprotection is related to unique properties of the TS molecule or is dependent on the cellular release and activity of unesterified alpha-tocopherol (T). To test the unique cytoprotective nature of TS in vivo, the protective ability of T and tocopherol esters against carbon tetrachloride (CCl4)-induced hepatotoxicity in rats was examined. Hepatoprotection [determined by serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and histopathology] was not observed after T (or tocopheryl acetate and tocopheryl nicotinate) administration, even though this treatment resulted in a fivefold elevation in hepatic T content. Only pretreatment with TS (100 mg/kg, intraperitoneally) resulted in partial hepatoprotection against CCl4 (2.9 g/kg, orally) toxicity. These findings suggest that hepatoprotection results not from the cellular accumulation of T but rather from the intact TS molecule. To test this hypothesis, the hepatoprotective capacity of cholesteryl hemisuccinate (CS), unesterified cholesterol, and cholesteryl acetate (CA) was examined against CCl4 toxicity. As observed with the tocopherol derivatives, pretreatment with unesterified cholesterol or CA demonstrated no protective ability. However, when rats were pretreated with CS (100 mg/kg), the hepatotoxic effects of CCl4 (elevated serum AST and ALT levels and centrilobular necrosis) were completely prevented. The prevention of CCl4-induced hepatotoxicity by CS and TS do not appear to result from an alteration in hepatic drug metabolism. These data clearly demonstrate that CS and TS are unique and powerful cytoprotective agents against CCl4 hepatotoxicity in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Radioiodination of a monoclonal antibody using N-succinimidyl 5-iodo-3-pyridinecarboxylate

The potential utility of N-succinimidyl 5-iodo-3-pyridinecarboxylate (SIPC) for the radioiodination of monoclonal antibodies was investigated. Paired-label studies were performed using the anti-tenascin antibody 81C6 in athymic mice bearing subcutaneous D-54 MG human glioma xenografts. Radiolabeling was also done using N-succinimidyl 3-iodobenzoate (SIB). Radioiodination of SIPC and SIB both proceeded in 60-80% yield, but protein coupling efficiencies with SIB were higher (76 +/- 16 vs 60 +/- 7%). Immunoreactivity and affinity of both preparations were similar. Using SIPC, thyroid uptake was quite low, decreasing from 0.3% at day 1 to 0.05% at day 8. Tumor uptake reached 46 +/- 11% injected dose/g at day 1 but declined gradually thereafter. This apparent decline reflected the rapid growth of these xenografts since tumor accumulation expressed as percentage of injected dose remained nearly constant up to day 9. These results suggest that SIPC, like SIB, offers significant advantages for labeling antibodies when compared with conventional protein iodination methods.

[Measurement of the single muscle fiber action potentials and jitter value in tibialis anterior muscles of rabbits in situ]

With a home-made jitter data processing board and microcomputer for recording extracellular single fiber action potential (SF-AP), variations of the time intervals of the SF-AP pairs, or the jitters, from two adjacent muscle fibers in the unique motor unit in tibialis' anterior in response to repeated stimuli were measured. The jitter distribution of 936 recorded from 7 rabbits was positively showed with a percentile value of P75-P25 of 54.99-14.61 microseconds. The data suggested that the lower limit was smaller than that of skeletal muscles in normal human and that there exists also some differences in the jitter values of SFEMG between human and rabbit muscles.