Complement Activation by an Anti-Dengue/Zika Antibody with Impaired Fcγ Receptor Binding Provides Strong Efficacy and Abrogates Risk of Antibody-Dependent Enhancement

To combat infectious diseases, vaccines are considered the best prophylactic strategy for a wide range of the population, but even when vaccines are effective, the administration of therapeutic antibodies against viruses could provide further treatment options, particularly for vulnerable groups whose immunity against the viruses is compromised. Therapeutic antibodies against dengue are ideally engineered to abrogate binding to Fcγ receptors (FcγRs), which can induce antibody-dependent enhancement (ADE). However, the Fc effector functions of neutralizing antibodies against SARS-CoV-2 have recently been reported to improve post-exposure therapy, while they are dispensable when administered as prophylaxis. Hence, in this report, we investigated the influence of Fc engineering on anti-virus efficacy using the anti-dengue/Zika human antibody SIgN-3C and found it affected the viremia clearance efficacy against dengue in a mouse model. Furthermore, we demonstrated that complement activation through antibody binding to C1q could play a role in anti-dengue efficacy. We also generated a novel Fc variant, which displayed the ability for complement activation but showed very low FcγR binding and an undetectable level of the risk of ADE in a cell-based assay. This Fc engineering approach could make effective and safe anti-virus antibodies against dengue, Zika and other viruses.

Comprehensive engineering of a therapeutic neutralizing antibody targeting SARS-CoV-2 spike protein to neutralize escape variants

The emergence of escape variants of SARS-CoV-2 carrying mutations in the spike protein poses a challenge for therapeutic antibodies. Here, we show that through the comprehensive engineering of the variable region of the neutralizing monoclonal antibody 5A6, the engineered antibody, 5A6CCS1, is able to neutralize SARS-CoV-2 variants that escaped neutralization by the original 5A6 antibody. In addition to the improved affinity against variants, 5A6CCS1 was also optimized to achieve high solubility and low viscosity, enabling a high concentration formulation for subcutaneous injection. In cynomolgus monkeys, 5A6CCS1 showed a long plasma half-life and good subcutaneous bioavailability through engineering of the variable and constant region. These data demonstrate that 5A6CCS1 is a promising antibody for development against SARS-CoV-2 and highlight the importance of antibody engineering as a potential method to counteract escape variants.

Elimination of plasma soluble antigen in cynomolgus monkeys by combining pH-dependent antigen binding and novel Fc engineering

A conventional antibody targeting a soluble antigen in circulation typically requires a huge dosage and frequent intravenous administration to neutralize the antigen. This is because antigen degradation is reduced by the formation of antigen–antibody immune complexes, which escape from lysosomal degradation using neonatal Fc receptor (FcRn)-mediated recycling. To address this, we developed an antigen-sweeping antibody that combines pH-dependent antigen binding and Fc engineering to enhance Fc receptor binding. The sweeping antibody actively eliminates the plasma antigens by increasing the cellular uptake of the immune complex and dissociating the antigens in the acidic endosome for degradation. Strong antigen sweeping can reduce the dosage, potentially achieve higher efficacy, and expand the scope of antigen space available for targeting by antibodies. In this study, to further improve the sweeping efficacy, we developed a novel antibody Fc variant by enhancing Fcγ receptor IIb (FcγRIIb) binding and modulating charge characteristics for increased cellular uptake of the immune complex, together with enhancing FcRn binding for efficient salvage of the antigen-free antibodies. Our Fc variant achieved strong antigen sweeping in cynomolgus monkeys with antibody pharmacokinetics comparable to a wild-type human IgG₁ antibody. The positive-charge substitutions enhanced uptake of the immune complex by FcγRIIb-expressing cells in vitro, which was completely inhibited by an anti-FcγRIIb antibody. This suggests that the strong in vivo sweeping efficacy improved by the charge engineering is more likely achieved by FcγRIIb-dependent uptake of the immune complex rather than nonspecific uptake. We expect this novel Fc engineering can maximize the antigen sweeping efficacy even in humans and create novel therapeutic antibodies that meet unmet medical needs for patients.

Predicting Method for the Human Plasma Concentration-Time Profile of a Monoclonal Antibody from the Half-life of Non-human Primates

Efficiency (speed and cost) and animal welfare are important factors in the development of new drugs. A novel method (the half-life method) was developed to predict the human plasma concentration-time profile of a monoclonal antibody (mAb) after intravenous (i.v.) administration using less data compared to the conventional approach; moreover, predicted results were comparable to conventional method. This new method use human geometric means of pharmacokinetics (PK) parameters and the non-human primates (NHP) half-life of each mAb. PK data on mAbs in humans and NHPs were collected from literature focusing on linear elimination, and the two-compartment model was used for analysis. The following features were revealed in humans: 1) the coefficient of variation in the distribution volume of the central compartment and at steady state of mAbs was small (22.6 and 23.8%, respectively) and 2) half-life at the elimination phase (t1/2_β) was the main contributor to plasma clearance. Moreover, distribution volume showed no significant correlation between humans and NHPs, and human t1/2_β showed a good correlation with allometrically scaled t1/2_β of NHP. Based on the features revealed in this study, we propose a new method for predicting the human plasma concentration-time profile of mAbs after i.v. dosing. When tested, this half-life method showed reasonable human prediction compared with a conventional empirical approach. The half-life method only requires t1/2_β to predict human PK, and is therefore able to improve animal welfare and potentially accelerate the drug development process.

Exploitation of Elevated Extracellular ATP to Specifically Direct Antibody to Tumor Microenvironment

The extracellular adenosine triphosphate (ATP) concentration is highly elevated in the tumor microenvironment (TME) and remains tightly regulated in normal tissues. Using phage display technology, we establish a method to identify an antibody that can bind to an antigen only in the presence of ATP. Crystallography analysis reveals that ATP bound in between the antibody-antigen interface serves as a switch for antigen binding. In a transgenic mouse model overexpressing the antigen systemically, the ATP switch antibody binds to the antigen in tumors with minimal binding in normal tissues and plasma and inhibits tumor growth. Thus, we demonstrate that elevated extracellular ATP concentration can be exploited to specifically target the TME, giving therapeutic antibodies the ability to overcome on-target off-tumor toxicity.

Long lasting neutralization of C5 by SKY59, a novel recycling antibody, is a potential therapy for complement-mediated diseases

Dysregulation of the complement system is linked to the pathogenesis of a variety of hematological disorders. Eculizumab, an anti-complement C5 monoclonal antibody, is the current standard of care for paroxysmal nocturnal hemoglobinuria (PNH) and atypical hemolytic uremic syndrome (aHUS). However, because of high levels of C5 in plasma, eculizumab has to be administered biweekly by intravenous infusion. By applying recycling technology through pH-dependent binding to C5, we generated a novel humanized antibody against C5, SKY59, which has long-lasting neutralization of C5. In cynomolgus monkeys, SKY59 suppressed C5 function and complement activity for a significantly longer duration compared to a conventional antibody. Furthermore, epitope mapping by X-ray crystal structure analysis showed that a histidine cluster located on C5 is crucial for the pH-dependent interaction with SKY59. This indicates that the recycling effect of SKY59 is driven by a novel mechanism of interaction with its antigen and is distinct from other known pH-dependent antibodies. Finally, SKY59 showed neutralizing effect on C5 variant p.Arg885His, while eculizumab does not inhibit complement activity in patients carrying this mutation. Collectively, these results suggest that SKY59 is a promising new anti-C5 agent for patients with PNH and other complement-mediated disorders.

Identification of human IgG1 variant with enhanced FcRn binding and without increased binding to rheumatoid factor autoantibody

Various studies have demonstrated that Fc engineering to enhance neonatal Fc receptor (FcRn) binding is effective for elongating half-life or increasing cellular uptake of IgG. A previous study has shown that a N434H mutation to enhance FcRn binding resulted in increased binding to rheumatoid factor (RF) autoantibody, which is not desirable for therapeutic use in autoimmune disease. In this study, we first showed that all the existing Fc variants with enhanced FcRn binding also show increased RF binding, and then identified specific mutations that could be introduced to those Fc variants to reduce the RF binding. Furthermore, we generated novel Fc variants that do not increase RF binding and show half-lives of 45 d in cynomolgus monkey, which is longer than those of previously reported Fc variants. In addition, we generated novel Fc variants with antigen sweeping activity that do not increase RF binding. We expect that these novel Fc variants will be useful as antibody therapeutics against autoimmune diseases.

Inhibitory FcγRIIb-Mediated Soluble Antigen Clearance from Plasma by a pH-Dependent Antigen-Binding Antibody and Its Enhancement by Fc Engineering

Fc engineering can modulate the Fc-FcγR interaction and thus enhance the potency of Abs that target membrane-bound Ags, but it has not been applied to Abs that target soluble Ags. In this study, we revealed a previously unknown function of inhibitory FcγRII in vivo and, using an Ab that binds to Ag pH dependently, demonstrated that the function can be exploited to target soluble Ag. Because pH-dependent Ab dissociates Ag in acidic endosome, its Ag clearance from circulation reflects the cellular uptake rate of Ag/Ab complexes. In vivo studies showed that FcγR but not neonatal FcR contributes to Ag clearance by the pH-dependent Ab, and when Fc binding to mouse FcγRII and III was increased, Ag clearance was markedly accelerated in wild-type mice and FcR γ-chain knockout mice, but the effect was diminished in FcγRII knockout mice. This demonstrates that mouse FcγRII efficiently promotes Ab uptake into the cell and its subsequent recycling back to the cell surface. Furthermore, when a human IgG1 Fc variant with selectively increased binding to human FcγRIIb was tested in human FcγRIIb transgenic mice, Ag clearance was accelerated without compromising the Ab half-life. Taken together, inhibitory FcγRIIb was found to play a prominent role in the cellular uptake of monomeric Ag/Ab immune complexes in vivo, and when the Fc of a pH-dependent Ab was engineered to selectively enhance human FcγRIIb binding, the Ab could accelerate soluble Ag clearance from circulation. We assume such a function would enhance the therapeutic potency of Abs that target soluble Ags.

Pathogenicity of exopolysaccharide-producing Actinomyces oris isolated from an apical abscess lesion

Aim

To demonstrate a capacity for producing exopolysaccharides (EPSs) and an ability to form biofilm on abiotic materials of Actinomyces oris strain K20.

Methodology

The productivity of EPSs and the ability to form biofilm of strain K20 were evaluated by measuring viscosity of spent culture media and by scanning electron microscopy (SEM) and the biofilm assay on microtitre plates, respectively. High-performance liquid chromatography was used to determine the chemical composition of the viscous materials. To examine the role of the viscous materials attributable to the pathogenicity in this organism, the ability of strain K20 to induce abscess formation was compared in mice to that of ATCC 27044.

Results

The viscosity of the spent culture media of K20 was significantly higher than that of ATCC 27044. Strain K20 showed dense meshwork structures around the cells and formed biofilms on microtitre plates, whereas ATCC 27044 did not. Chemical analysis of the viscous materials revealed that they were mainly composed of neutral sugars with mannose constituting 77.5% of the polysaccharides. Strain K20 induced persistent abscesses in mice lasting at least 5 days at a concentration of 10⁸ cells mL⁻¹, whereas abscesses induced by ATCC 27044 healed and disappeared or decreased in size at day 5.

Conclusions

Strain K20 produced EPSs, mainly consisting of mannose, and formed biofilms. This phenotype might play an important role for A. oris to express virulence through the progression of apical periodontitis.

Association of SLCO1B3 polymorphism with intracellular accumulation of imatinib in leukocytes in patients with chronic myeloid leukemia

Intracellular concentration of imatinib in leukemic cells is thought to affect the clinical efficacy of this drug in patients with chronic myeloid leukemia (CML); however, there is no report that directly indicates the relationship between intracellular concentration and clinical outcome and/or, plasma concentration. In addition, the impacts of genetic variations of drug transporters, which mediate leukocyte concentration of imatinib, are unknown. In the present study, we investigated the correlation between intracellular imatinib concentrations in leukocytes, plasma imatinib levels, and genotypes of drug transporters, including ATP binding cassette B1 (ABCB), ABCG2, solute carrier 22A1 (SLC22A1), solute carrier organic anion transporter family members 1B1 (SLCO1B1) and SLCO1B3. The imatinib levels in leukocytes were determined using HPLC in 15 patients with chronic phase CML. No significant correlation between intracellular and plasma concentrations of imatinib was observed. The intracellular concentration was comparable in both patients with or without complete cytogenetic response. The intracellular imatinib concentration was significantly higher in patients with SLCO1B3 334TT than in those with 334TG/GG (p=0.0188). Plasma concentrations were similar in both SLCO1B3 genotypes (p=0.860), thereby resulting in the intracellular to plasma concentration ratio being higher in patients with SLCO1B3 334TT than those with 334 TG/GG (p=0.0502). These results suggested that the SLCO1B3 334T>G polymorphism could have a significant impact on the intracellular concentration of imatinib in leukocytes as a promising biomarker for personalized treatment of CML patients.

Contribution of BCR-ABL-independent activation of ERK1/2 to acquired imatinib resistance in K562 chronic myeloid leukemia cells

BCR-ABL tyrosine kinase, generated from the reciprocal chromosomal translocation t(9;22), causes chronic myeloid leukemia (CML). BCR-ABL is inhibited by imatinib; however, several mechanisms of imatinib resistance have been proposed that account for loss of imatinib efficacy in patients with CML. Previously, we showed that overexpression of the efflux drug transporter P-glycoprotein partially contributed to imatinib resistance in imatinib-resistant K562 CML cells having no BCR-ABL mutations. To explain an additional mechanism of drug resistance, we established a subclone (K562/R) of the cells and examined the BCR-ABL signaling pathway in these and wild-type K562 (K562/W) cells. We found the K562/R cells were 15 times more resistant to imatinib than their wild-type counterparts. In both cell lines, BCR-ABL and its downstream signaling molecules, such as ERK1/2, ERK5, STAT5, and AKT, were phosphorylated in the absence of imatinib. In both cell lines, imatinib effectively reduced the phosphorylation of all the above, except ERK1/2, whose phosphorylation was, interestingly, only inhibited in the wild-type cells. We then observed that phospho-ERK1/2 levels decreased in the presence of siRNA targeting BCR-ABL, again, only in the K562/W cells. However, using an ERK1/2 inhibitor, U0126, we found that we could reduce phospho-ERK1/2 levels in K562/R cells and restore their sensitivity to imatinib. Taken together, we conclude that the BCR-ABL-independent activation of ERK1/2 contributes to imatinib resistance in K562/R cells, and that ERK1/2 could be a target for the treatment of CML patients whose imatinib resistance is due to this mechanism.

Genetic ablation of orexin neurons in mice results in narcolepsy, hypophagia, and obesity

Orexins (hypocretins) are a pair of neuropeptides implicated in energy homeostasis and arousal. Recent reports suggest that loss of orexin-containing neurons occurs in human patients with narcolepsy. We generated transgenic mice in which orexin-containing neurons are ablated by orexinergic-specific expression of a truncated Machado-Joseph disease gene product (ataxin-3) with an expanded polyglutamine stretch. These mice showed a phenotype strikingly similar to human narcolepsy, including behavioral arrests, premature entry into rapid eye movement (REM) sleep, poorly consolidated sleep patterns, and a late-onset obesity, despite eating less than nontransgenic littermates. These results provide evidence that orexin-containing neurons play important roles in regulating vigilance states and energy homeostasis. Orexin/ataxin-3 mice provide a valuable model for studying the pathophysiology and treatment of narcolepsy.

Behaviour of pathogenic E. coli and Salmonella enteritidis in small domestic sewage treatment apparatus ("Johkasou")

"Johkasou" is a small sewage treatment apparatus commonly used in Japan which can effectively treat domestic wastewater in places where a public sewage system is difficult to supply. The behaviour of enterohaemorrhagic E. coli O157 and Salmonella enteritidis in a "Johkasou" was studied. Their reduction rates depended significantly on the water temperature in the "Johkasou" with minimal decrease in numbers at 10 degrees C within 48 h. The reduction rates increased at 20 degrees C and 30 degrees C where 4 log reduction could be expected. The reduction rates were influenced by the BOD of the solutions that contained the pathogens with the lower the BOD the higher the reduction rate. The reduction rates were about the same between both pathogens. The result showed that it was necessary to disinfect the effluent as some pathogens can pass through the apparatus when some users of the apparatus excrete pathogens.

Elucidation of accuracy in calibration of MR signal intensity based on transmission amplitude method

To calibrate magnetic resonance (MR) signal intensity that depends on radio frequency (RF) coil loading, the transmission amplitude (TRA) for the excitation in the transmit-receive RF coil has been used as a good index in the so-called TRA method. As this TRA method needs neither an internal reference nor an additional external reference for the calibration, its accuracy is free from reference measurements. This study elucidated the calibration accuracy of MR signal intensities based on the TRA method. A cylindrical gel phantom was used for accuracy measurements with a 1.5-T MRI unit with conventional T1 imaging as a simple pulse sequence for various loading conditions. The brain parenchyma of eight healthy volunteers also showed calibrated MR signal deviations. The error of the phantom calibration measurements was 2.18% (S.D.%). The background noise intensity of images was theoretically derived to correlate with the impedance mismatching of the RF coil, which is inevitable for fixed tuning, even for automatic tuning that is not always exact. Taking into account this noise intensity, the calibration method was modified to reduce its error to 1.50%. The standard deviations of the calibrated values in the thalamus and frontal white matter were 2.9 and 3.8%, respectively. We suggest that the modified TRA method is a practical and reliable technique to obtain clinical numeric evidence.

Wavelet compression on detection of brain lesions with magnetic resonance imaging

The purpose of this report is to assess clinically acceptable compression ratios on the detection of brain lesions at magnetic resonance imaging (MRI). Four consecutive T2-weighted and the corresponding T1-weighted images obtained in 20 patients were studied for 109 anatomic sites including 50 with lesions and 59 without lesions. The images were obtained on a 1.5-T MR unit with a pixel size of 0.9 to 1.2 x 0.47 mm and a section thickness of 5 mm. The image data were compressed by wavelet-based algorithm at ratios of 20:1, 40:1, and 60:1. Three radiologists reviewed these images on an interactive workstation and rated the presence or absence of a lesion with a 50 point scale for each anatomic site. The authors also evaluated the influence of pixel size on the quality of image compression. At receiver operating characteristic (ROC) analysis, no statistically significant difference was detected at a compression ratio of 20:1. A significant difference was observed with 40:1 compressed images for one reader (P = .023), and with 60:1 for all readers (P = .001 to .012). A root mean squared error (RMSE) was higher in 0.94- x 0.94-mm pixel size images than in 0.94- x 0.47-mm pixel size images at any compression ratio, indicating compression tolerance is lower for the larger pixel size images. The RMSE, subjective image quality, and error images of 10:1 compressed 0.94- x 0.94-mm pixel size images were comparable with those of 20:1 compressed 0.94- x 0.47-mm pixel size images. Wavelet compression can be acceptable clinically at ratios as high as 20:1 for brain MR images when a pixel size at image acquisition is around 1.0 x 0.5 mm, and as high as 10:1 for those with a pixel size around 1.0 x 1.0 mm.

Orexin-induced hyperlocomotion and stereotypy are mediated by the dopaminergic system

We demonstrated involvement of the ventral tegmental area (VTA) dopaminergic system in orexin-induced hyperlocomotion and stereotypy in rats. In double-label immunohistochemical study of rat brain, we found that tyrosine hydroxylase (TH)-immunoreactive cells in the VTA received innervation from orexin immunoreactive-fibers. Orexin-A induced an increase in [Ca(2+)](i) in isolated A10 dopamine neurons in a dose-dependent manner. In behavioral studies, we found that orexin-A induced hyperlocomotion, stereotypy and grooming behavior when administered centrally in rats, and these effects were abolished by dopamine D(2) (haloperidol and sulpiride) or D(1) (SCH23390) antagonists. These results suggest that the orexin-induced hyperlocomotion, stereotypy and grooming behavior are mediated by the dopaminergic system and this pathway might be involved in orexin-induced emotional responses.

Natural progression of osteochondritis dissecans of the humeral capitellum: initial observations

PURPOSE

To determine the earliest findings, subsequent changes, and natural course of osteochondritis dissecans of the humeral capitellum.

MATERIALS AND METHODS

Among 95 patients with osteochondritis dissecans of the humeral capitellum, 16 (mean age, 12.5 years) were selected for this retrospective study because they seemed to have early osteochondritis dissecans and had been followed up without any surgical treatment for 6 months or more (mean, 3.5 years).

RESULTS

The initial imaging appearances of the 16 patients' lesions were divided into two types: localized subchondral bone flattening without fragments in seven, and nondisplaced fragments in nine. Patients with lesion flattening had younger ages and significantly shorter durations of symptoms, and most had open growth plates. In five of the seven with flattening, new bone formed over the flattened bone, and the fragments united after arm motion reduction. In contrast, patients with nondisplaced fragments at clinical presentation had longer durations of symptoms with continued arm motion, and their nondisplaced fragments failed to unite.

CONCLUSION

The earliest feature of osteochondritis dissecans is subchondral bone flattening, over which new bone subsequently forms. The new bone then can unite with the underlying bone. However, if subjected to repetitive forces over a given time, unstable fragments develop. These fragments, even if not yet displaced, are unable to unite.

Orexin-induced food intake involves neuropeptide Y pathway

Orexins (orexin-A and -B) are recently identified neuropeptides, which are thought to be implicated in the regulation of feeding behavior. We used a NPY-Y1 receptor specific antagonist, BIBO3304, to examine whether NPY is involved in orexin-induced feeding behavior. Intracerebroventricular administration of orexin-A (10 nmol) induced food intake in rats (food intake for 3 h; vehicle 0.3+/-0.2 g vs. orexin-A 10 nmol, 4.0+/-0.5 g, n=4). Orexin-induced feeding behavior was partially inhibited by prior administration of BIBO3304 (3 h food intake: orexin-A 10 nmol, 4.0+/-0.5 g vs. BIBO3304 (60 microgram) + orexin-A 10 nmol, 2.2+/-0.2 g, n=4). A low dose of BIBO3304 (30 microgram) did not show a significant inhibitory effect. BIBO3457, an inactive enantiomer, used as a negative control, did not show any inhibitory effect on orexin-A-induced feeding behavior. Fos expression was observed in NPY-containing neurons in the arcuate nucleus 1 h after orexin-A (10 nmol) was administered intracerebroventricularly (control 0.3+/-0.08%, orexin-A 10.2+/-0.8%, n=5 rats/group). These observations suggest that NPY is involved in orexin-induced feeding behavior. However, BIBO3304 did not completely abolish the effect of orexin-A. These results suggest that orexin-A elicits feeding behavior partially via the NPY pathway. The NPY system could be the one of downstream pathways by which orexin-A induces feeding behavior. Another pathway may also be involved in orexin-A-induced feeding behavior, because BIBO3304 did not completely abolish orexin-A-induced feeding behavior.

Sonographic assessment of osteochondritis dissecans of the humeral capitellum

OBJECTIVE

The purpose of this study was to determine the efficacy of sonography for revealing osteochondritis dissecans of the humeral capitellum.

SUBJECTS AND METHODS

Twenty-seven patients with capitellar osteochondritis dissecans (27 males; range, 11-20 years; mean age, 14 years) underwent radiography and sonography performed with a 7.5-MHz mechanical sector probe. Lesions were assessed as stable or unstable. The sonographic assessment was compared with radiographic assessment in 27 patients, MR assessment obtained in 10, and surgical findings in 15.

RESULTS

Sonographic assessment agreed with radiographic assessment in 23 of the 27 patients, MR assessment in nine of the 10, and surgical findings in 14 of the 15. Sonography revealed that two lesions, which had been underestimated on radiography, were unstable.

CONCLUSION

Sonography facilitates the assessment of capitellar lesions so that treatment can be optimized.

Orexins/hypocretins regulate drinking behaviour

Orexin/hypocretins are recently identified neuropeptides which regulate feeding behaviour. We found orexins increased water intake when administrated intracerebroventricularly to rats. The effect of orexin-A was more potent as compared with orexin-B, suggesting the possible involvement of OX(1) receptor. The efficacy of orexin-A was almost comparable with that of angiotensin II, and the effect lasted more than 3 h. Prepro-orexin mRNA level was up-regulated when rats were deprived of water. Orexin-immunoreactive varicose axons were observed in the subfornical organ and area postrema, regions implicated in drinking behaviour. These observations suggest a physiological role for orexin as mediators that regulate drinking behaviour.

Distribution of orexin neurons in the adult rat brain

Orexin (ORX)-A and -B are recently identified neuropeptides, which are specifically localized in neurons within and around the lateral hypothalamic area (LHA) and dorsomedial hypothalamic nucleus (DMH), the regions classically implicated in feeding behavior. Here, we report a further study of the distribution of ORX-containing neurons in the adult rat brain to provide a general overview of the ORX neuronal system. Immunohistochemical study using anti-ORX antiserum showed ORX-immunoreactive (ir) neurons specifically localized within the hypothalamus, including the perifornical nucleus, LHA, DMH, and posterior hypothalamic area. ORX-ir axons and their varicose terminals showed a widespread distribution throughout the adult rat brain. ORX-ir nerve terminals were observed throughout the hypothalamus, including the arcuate nucleus and paraventricular hypothalamic nucleus, regions implicated in the regulation of feeding behavior. We also observed strong staining of ORX-ir varicose terminals in areas outside the hypothalamus, including the cerebral cortex, medial groups of the thalamus, circumventricular organs (subfornical organ and area postrema), limbic system (hippocampus, amygdala, and indusium griseum), and brain stem (locus coeruleus and raphe nuclei). These results indicate that the ORX system provides a link between the hypothalamus and other brain regions, and that ORX-containing LHA and DMH neurons play important roles in integrating the complex physiology underlying feeding behavior.

Neurons containing orexin in the lateral hypothalamic area of the adult rat brain are activated by insulin-induced acute hypoglycemia

Orexin-A and -B (also known as hypocretin-1 and -2) are neuropeptides which stimulate food intake when administered intracerebroventricularly. Orexins are specifically localized in neurons within and around the lateral hypothalamic area (LHA). Previous electrophysiological studies have demonstrated that some neurons in the LHA are activated by hypoglycemia, and are therefore termed 'glucose-sensitive neurons'. In the present study, we examined whether orexin-containing neurons are activated in the hypoglycemic states, using Fos-like immunoreactivity (FLI) as a marker of neuronal activation. We observed that FLI was induced in the LHA by acute insulin treatment. Double staining with anti-Fos and anti-orexin antibodies revealed that up to 33% of the orexin-containing neurons in the LHA also expressed FLI under the hypoglycemic condition. These results suggest that some populations of neurons which contain orexins are activated under hypoglycemic conditions.

Peptidoglycan-hydrolyzing activity of the FlgJ protein, essential for flagellar rod formation in Salmonella typhimurium

Because the rod structure of the flagellar basal body crosses the inner membrane, the periplasmic space, and the outer membrane, its formation must involve hydrolysis of the peptidoglycan layer. So far, more than 10 genes have been shown to be required for rod formation in Salmonella typhimurium. Some of them encode the component proteins of the rod structure, and most of the remaining genes are believed to encode proteins involved in the export process of the component proteins. Although FlgJ has also been known to be involved in rod formation, its exact role has not been understood. Recently, it was suggested that the C-terminal half of the FlgJ protein has homology to the active center of some muramidase enzymes from gram-positive bacteria. In this study, we showed that the purified FlgJ protein from S. typhimurium has a peptidoglycan-hydrolyzing activity and that this activity is localized in its C-terminal half. Through oligonucleotide-directed mutagenesis, we constructed flgJ mutants with amino acid substitutions in the putative active center of the muramidase. The resulting mutants produced FlgJ proteins with reduced enzymatic activity and showed poor motility. These results indicate that the muramidase activity of FlgJ is essential for flagellar formation. Immunoblotting analysis with the fractionated cell extracts revealed that FlgJ is exported to the periplasmic space, where the peptidoglycan layer is localized. On the basis of these results, we conclude that FlgJ is the flagellum-specific muramidase which hydrolyzes the peptidoglycan layer to assemble the rod structure in the periplasmic space.

Structure, tissue distribution, and pharmacological characterization of Xenopus orexins

We isolated the Xenopus gene encoding prepro-orexin to predict the structures of orexins in submammalian chordates. Putative mature Xenopus orexin-A and -B are highly similar to each mammalian counterpart. Especially, the C-terminal 10 residues were highly conserved among these species and isopeptides. Immunohistochemical examination of Xenopus brain revealed that orexin-containing neurons were highly specifically localized in the ventral hypothalamic nucleus. A rich network of immunoreactive fibers was found in various regions of the Xenopus brain. The distribution was similar to that of mammalian orexins. Xenopus orexin-A and -B specifically bind and activate human orexin receptors expressed in Chinese hamster ovary cells. Of interest, Xenopus orexin-B had several-fold higher affinity to human OX2R compared with human orexins. These results suggest that Xenopus orexin-B might be a useful pharmacological tool as an OX2R selective high-affinity agonist.

Polymerization shrinkage and contraction force of composite resin restorative inserted with "Megafiller"

This study quantified the contraction force and polymerization shrinkage of composite resins with/without beta-Quartz Glass Ceramic Inserts (BQCI) as "Megafiller". The materials used for the determination included a chemically cured composite and five light-cured composites. The system for measuring contraction force consisted of a transparent teflon tube for preparing the specimen, a small load cell, a dynamic strain gauge and a pen-recorder. After the composite was packed into the teflon mold, a BQCI (Type R3) was inserted through the opening and the specimen was cured. Linear polymerization shrinkage of the composites was measured every 10 seconds from the start of mixing or irradiation to 90 minutes by the mercury bath method. Three pieces each of BQCI (Type T3) were inserted in each specimen. The results suggested that BQCI was markedly effective in reducing polymerization shrinkage, but was not always effective in reducing the contraction force during polymerization.

The trophic effects of long chain triglycerides on the atrophic ileal mucosa of rats

Rats with atrophic intestinal mucosa due to enteral nutrition supplied by an elemental diet (ED) for 4 weeks or more, received a fat-enriched ED containing 10% long chain triglycerides (10% FED) orally. The atrophic ileal mucosa became trophic 4 weeks after administration of the 10% FED. Ornithine decarboxylase activity in the ileal mucosa increased 3 days after the administration of 10% FED. Rats with atrophic intestinal mucosa that had undergone a 70% proximal jejunoileectomy, received an oral ED containing 4% long chain triglycerides (4% FED). In the jejunoileectomized rats, marked proliferation of the remaining ileum was observed irrespective of diet, when compared with the transected control group. In the transected group, the 4% FED had trophic effects on the ileum, but in the jejunoileectomized group, the 4% FED had no significant trophic effect on the remaining ileum. In conclusion, long chain triglycerides had mild trophic effects on ileal mucosa and were effective in the treatment of atrophic intestinal mucosa. However, the trophic effects of fat were apparently masked by the marked proliferation of the ileal mucosa following jejunoileectomy.

[Evaluation of EC-IC bypass flow by MR angiography using the presaturation technique]

MR angiography studies using the presaturation technique were performed in 7 patients who had received extra-intracranial (EC-IC) bypass surgery. With presaturation on the bypass vessels, disappearance of intracranial vascular signals suggests bypass effect. In our studies, good bypass effect was shown in 3 cases and poor effect in 2 cases, which correlates well to concurrent angiography. In two cases, bypass effect was shown only in a few cortical branches of MCA, but angiography confirmed recanalization of occluded internal carotid artery in one case, and growth of large network of transdural anastomoses in the other.

Promotion of healing by orally administered glutamine in elemental diet after small intestinal injury by X-ray radiation

Glutamine was administered orally to rats with damaged small intestinal mucosa as the result of injury by X-ray radiation at 10 Gy to the abdomen. The healing effects of glutamine on the injured mucosa were studied serially from the day of radiation (Day 0) to Day 4. The rats received two types of isocaloric elemental diet, Gln( + ) containing 2% glutamine and Gln( - ) containing no glutamine, by paired feeding. From Day 2 to Day 4, the wet weight, protein content, and DNA content of the jejunal mucosa were significantly greater in the Gln(+) than in the Gln(-) group. On Day 3, when the damage of the intestinal mucosa was the severest, the crypt cell production rate in the jejunum was significantly higher in the Gln(+) than in the Gln(-) group. The permeability of the intestinal mucosa to 51CrEDTA, administered to the rat stomach through an oro-gastric tube, remained significantly lower in the Gln( + ) group . Light microscopic findings showed that oedema in the lamina propria mucosae of jejunum and fusion of jejunal villi were milder in the Gln(+) group on Day 4. when the mucosal mass began to recover. The arterial and portal blood glutamine concentration, and glutamine extraction by the gut from arterial blood and phosphate-dependent glutaminase activity in the jejunal mucosa, were higher in the Gln(+) than in the Gln(--) group. Ornithine decarboxylase activity was increased in both the jejunum and the ileum from Day 3, but no difference was observed between the two groups. These findings suggest that, after X-ray radiation injury of the intestinal mucosa, the oral administration of the elemental diet containing 2% glutamine improved glutamine metabolism of the body, promoted the proliferation of jejunal epithelium, accelerated the recovery of the mucosal mass and the morphology of villi, and then contributed to maintaining the barrier function of the intestine from an early stage after the injury.

Influence of water on the transverse strength of posterior composite resins

In an attempt to evaluate the influence of water on the mechanical properties of composite resin, the transverse strengths of 15 commercially available composites were determined in water at 37 degrees C and compared with the strength measured in air after storage in water for periods of 1 day to 3 months. Some of the composites, including two which contained a blend filler, showed remarkable reduction of transverse strength when measured in air, according to the procedures specified in ISO 4049, in comparison with transverse strength measured in water. The change of water content in the material can predominantly affect the mechanical behavior of composite resin.

Deformation of the distal femur: a contribution towards the pathogenesis of osteochondrosis dissecans in the knee joint

Osteochondrosis dissecans (OD) is a process of subchondral bone necrosis occurring predominantly in young individuals at specific sites. The aetiology of this disease remains controversial with mechanical processes due to trauma and/or ischaemic factors being proposed. This study aims at explaining the aetiology of OD in the knee joint as a result of the particular deformation of the condyles. A finite element analysis of the distal third of the femur was performed. A three-dimensional model was developed based on computed tomography scans of a normal femur, consisting of cortical bone, cancellous bone and articular cartilage. This model was subjected to physiological loads at 0, 30, 60 and 90 degrees of knee flexion. A complex deformation was found within each condyle as well as between the two condyles. Both medial and lateral condyles are deformed in the medio-lateral direction and at the same time compressed between the patella and the tibia in the antero-posterior direction. This effect is highest at 60 degrees of knee flexion. In both planes, the medial condyle is distorted more than the lateral one. Strain concentration in the subchondral bone facing the patella varies with flexion, especially for angles exceeding 60 degrees. The deformation of the femur in the predominant locus of OD in the medial condyle exceeds that of the lateral condyle considerably. The analysis shows that repeated vigorous exercise including extreme knee flexion may produce rapidly changing strains which in turn could ultimately be responsible for local subchondral bone collapse.

[A randomized trial of single and multifraction radiation therapy for bone metastasis: a preliminary report]

From April, 1989 through January, 1990, a randomized trial was conducted to investigate the efficacy of single fraction radiation treatment (8, 10, 12, 15Gy) compared to a multifraction dose schedule (5Gy x 4, 5Gy x 5, 5Gy x 6) as a therapy for a bone metastasis. Both subjective and objective pain scores were used to measure the therapeutic results. A total of 31 patients participated in the trial and, for analysis, 27 of these patients were follow-up for more than 8 weeks after the start of the radiation therapy. The following statistics resulted. Of the single fraction series, symptomatic pain relief was obtained in 86% of the patients (12/14 treatment areas), and of the multifraction series, 92% (12/13). Further, a complete response was achieved in 57% (8/14) of the single fraction patients and 31% (4/13) of the multifraction patients, respectively. Between the two treatment regimens, no difference was found in the incidence of pain relief, speed of onset, or acute morbidity. Finally, no severe morbidity was seen in either arm.

[Intrahepatic bilomas after hepatic arterial embolization of malignant hepatic neoplasms]

Reviewed and discussed are six cases of intrahepatic biloma that developed after hepatic arterial embolization therapy for malignant hepatic tumors. All six cases were administered emulsion of adriamycin and lipiodol and/or sponge gel particles, as the etiology of their disease was considered to be bile duct necrosis due to obstructions of peripheral supplying arterial branches. From the 23rd to the 76 days after embolization therapy, each lesion was detected by CT scan, and every case showed an elevation of serum alkaline phoshatase. Further, in 4 cases, hepatobiliary scintigraphy revealed a delayed bile clearance in the hepatic lobe. In one case followed up for 2 months, only one of two lesions disappeared. And in 5 cases that were followed up for more than 4 months, recovery occurred in 4 cases without any further treatment, but another case required percutaneous drainage for 3.5 months to be cured. An intrahepatic biloma, or bile duct necrosis, is a complication that can arise from hepatic arterial embolization therapy, so that careful follow-up must be given.

[CT in gallbladder cancer; especially the extension of the tumor]

An efficacy of CT in the preoperative staging diagnosis of gallbladder cancer was evaluated. CT findings were recorded following general rules for surgical and pathological studies on cancer of biliary tract proposed by Japanese society of biliary surgery. Serosal invasion (S factor), direct hepatic invasion (H inf factor), lymph node metastasis (N factor), bile duct invasion (B factor), duodenal invasion (Du factor) and finally preoperative staging diagnosis were included in this study. Conclusion is as follows. 1) False positive results were predominating in S and H inf factor, sensitivity was 76.0% and 50.0% respectively. 2) In B factor, the result was poor, the sensitivity 44.4%. 3) In N factor, CT was effective, the sensitivity 77.6%. 4) Finally it was concluded that CT can play an important role in staging diagnosis of gallbladder cancer, the sensitivity was 93.1%.

[CT in staging gastric cancer]

CT pictures of 26 cases of advanced gastric cancer were reviewed. All the cases of gastric cancer were staged surgically and also histologically. 1) Gastric cancer was enhanced intensely. 2) About the diagnosis of the extension of the tumor, there were many problems to be solved in the future, but the result of final staging was satisfactory. 3) With further advent of technology and methodology in the field of CT, CT will play an important role in staging diagnosis of gastric cancer.

[A case of icteric hepatoma which succeeded internal fistulation after radiotherapy]

A case of icteric hepatoma was treated by TAE, arterial chemoinfusion and photoirradiation to the hepatic hilum. The patient was successfully discharged after radiotherapy, which was most effective for internal fistulation of obstructed bile duct and decreasing the size of portal tumor thrombus.

[CT of pulmonary eosinophilic granuloma]

CT findings of four cases of pulmonary eosinophilic Granuloma were discussed. In three cases, multiple nodular shadows or multiple cavitary lesions were observed in upper and middle lung field predominant. However, in one patient who had history of recurrent pneumothorax, CT revealed a honeycomb appearance and some bullous change as well. These findings seemed to represent a far advanced state of the disease. X-ray CT is excellent in demonstrating such pathological changes, and is indispensable in the diagnosis and follow up study of pulmonary eosinophilic granuloma.

[Radiotherapy of a pure seminoma of the testis]

Twenty-six cases of a pure seminoma of the testis that had been treated by postoperative radiotherapy have been reviewed. The overall 5-year survival rate was found to be 92.3%. Further, no severe adverse effects, including sterility, was found. Prophylactic mediastinal radiation is considered to be unnecessary, because supradiaphragmatic lymph node metastasis was seen in only 1 patient, who has remained disease-free 4.5 year after the treatment of a recurrence. Extranodal metastasis was seen 5 cases, 2 of these cases showing bone metastasis that was successfully treated, thereby achieving complete remission. A seminoma is considered to be one of the most curable malignant diseases, however, long-term follow up is a necessity since stage 1 seminoma has been found to show a generalized dissemination after a 16-year, disease-free interval.