Abstract P6-15-05: Randomized controlled trial of neoadjuvant eribulin mesylate versus paclitaxel in women with operable breast cancer (JONIE-3 study)

Background:

Although treatment of eribulin mesylate (E) improved overall survival in metastatic breast cancer (BC) patients, little is known about the efficacy in early BC. The hypothesis of this study is that sequential administration of E followed by FEC would have less toxic, particularly peripheral neuropathy, and also have similar effect compared to paclitaxel (P) followed by FEC as primary systemic therapy (PST) for woman with operable BC.

Methods:

This is a phase II multicenter open label study (UMIN000012817). Patients (pts) were randomly assigned to either E (1.4mg/m2, d1 and d8, q21 days, 4 cycles) + FEC (fluorouracil 500 mg/m2, epirubicin 100 mg/m2, and cyclophosphamide 500 mg/m2) or P (80mg/m2, weekly, 12 cycles) + FEC as PST. HER2+ patients were allowed to receive trastuzumab. Stratification factors were ER, HER2, and menopausal status. Primary endpoint was the incidence of peripheral sensory and motor neuropathy (PSN and PMN) with Grade 1 or higher according to CTCAE ver.4.0. Secondary endpoints were pathological complete response (pCR) rates (ypT0/is/ypN0), clinical response rates (CR+PR), and adverse events. Safety was assessed in all pts who received at least one dose of the study drug.

Results:

Between 12/2013 to 3/2016, 121 pts were randomly assigned equally to E + FEC and P + FEC. Excluding 5 pts from the primary assessment, 116 pts (58 in each group) were included in the full analysis set. The characteristics of the pts were similar in the two arms. At the end of E or P administration, the incidences of PSN were 55.4% and 92.9% in E and P arm, respectively (p<0.001). The incidences of PMN were 25.9% and 44.9% in E and P arm, respectively (p=0.049). At the end of E or P + FEC, PSN accounts for 38.9% in E arm and 85.2% in P arm (p<0.001), and PMN accounts for 20.7% in E arm and 32.8% in P arm (p=0.201). The pCR rates in E and P arm were 20.7% and 29.8% (p=0.092). The clinical response rates in E and P arm were 82.2% and 91.0% (p=0.108). No statistical significant difference was found in efficacy of PST between E and P.

Conclusion:

This randomized phase II study revealed that eribulin had favorable peripheral neuropathy profile with modest efficacy in the neoadjuvant setting, compared with paclitaxel.

Citation Format: Miura D, Hasegawa Y, Ishikawa T, Tachibana A, Horiguchi J, Hayashi M, Miyashita M, Kubota T, Narui K, Suzuki M, Akazawa K, Kohno N. Randomized controlled trial of neoadjuvant eribulin mesylate versus paclitaxel in women with operable breast cancer (JONIE-3 study) [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-15-05.

A multicenter retrospective study of the risk factors associated with medication-related osteonecrosis of the jaw after tooth extraction in patients receiving oral bisphosphonate therapy: can primary wound closure and a drug holiday really prevent MRONJ?

Root amputation, extraction of a single tooth, bone loss or severe tooth mobility, and an unclosed wound were significantly associated with increased risk of developing medication-related osteonecrosis of the jaw (MRONJ). We recommend a minimally traumatic extraction technique, removal of any bone edges, and mucosal wound closure as standard procedures in patients receiving bisphosphonates.

INTRODUCTION

Osteonecrosis of the jaws can occur following tooth extraction in patients receiving bisphosphonate drugs. Various strategies for minimizing the risk of MRONJ have been advanced, but no studies have comprehensively analyzed the efficacy of factors such as primary wound closure, demographics, and drug holidays in reducing its incidence. The purpose of this study was to retrospectively investigate the relationships between these various risk factors after tooth extraction in patients receiving oral bisphosphonate therapy.

METHODS

Risk factors for MRONJ after tooth extraction were evaluated using univariate and multivariate analysis. All patients were investigated with regard to demographics; type and duration of oral bisphosphonate use; whether they underwent a discontinuation of oral bisphosphonates before tooth extraction (drug holiday), and the duration of such discontinuation; and whether any additional surgical procedures (e.g., incision, removal of bone edges, root amputation) were performed.

RESULTS

We found that root amputation (OR = 6.64), extraction of a single tooth (OR = 3.70), bone loss or severe tooth mobility (OR = 3.60), and an unclosed wound (OR = 2.51) were significantly associated with increased risk of developing MRONJ.

CONCLUSIONS

We recommend a minimally traumatic extraction technique, removal of any bone edges, and mucosal wound closure as standard procedures in patients receiving bisphosphonates. We find no evidence supporting the efficacy of a pre-extraction short-term drug holiday from oral bisphosphonates in reducing the risk of MRONJ.

A multi-centre retrospective study of mandibular fractures: do occlusal support and the mandibular third molar affect mandibular angle and condylar fractures?

This retrospective study was performed to investigate the influence of occlusal support and the presence, state, and position of mandibular third molars on the incidence of mandibular angle and condylar fractures. The following variables were investigated: age, sex, cause of fracture, presence and state (impaction, angulation, and the number of roots) of the mandibular third molars, site of the mandibular fracture, presence of occlusal support, duration of intermaxillary fixation, and postoperative complications. Various risk factors for mandibular angle and condylar fractures were investigated by univariate analysis. The risk of mandibular angle fracture was significantly higher in patients with occlusal support and mandibular third molars. The risk of condylar fracture was significantly higher in patients without occlusal support or mandibular third molars. The position and angulation of the mandibular third molars were not significant risk factors in mandibular angle and condylar fractures. This study demonstrated the influence of occlusal support and the presence of mandibular third molars on the incidence of mandibular angle and condylar fractures. The presence of occlusal support may be a more important factor affecting mandibular angle or condylar fractures than the position of the mandibular third molars.

Chimeric mice with humanized livers: a unique tool for in vivo and in vitro enzyme induction studies

We performed in vivo and in vitro studies to determine the induction of human cytochrome P450 (CYP) using chimeric mice with humanized liver (PXB-mice^®) and human hepatocytes isolated from the PXB-mice (PXB-cells), which were derived from the same donor. For the in vivo study, PXB-mice were injected with 3-methylcholanthrene (3-MC, 2 or 20 mg/kg) or rifampicin (0.1 or 10 mg/kg) for four days. For the in vitro study, PXB-cells were incubated with 3-MC (10, 50, or 250 ng/mL) or with rifampicin (5 or 25 μg/mL). The CYP1A1 and 1A2, and CYP3A4 mRNA expression levels increased significantly in the PXB-mouse livers with 20 mg/kg of 3-MC (C_max, 12.2 ng/mL), and 10 mg/kg rifampicin (C_max, 6.9 μg/mL), respectively. The CYP1A1 mRNA expression level increased significantly in PXB-cells with 250 ng/mL of 3-MC, indicating lower sensitivity than in vivo. The CYP1A2 and CYP3A4 mRNA expression levels increased significantly with 50 ng/mL of 3-MC, and 5 μg/mL of rifampicin, respectively, which indicated that the sensitivities were similar between in vivo and in vitro studies. In conclusion, PXB-mice and PXB-cells provide a robust model as an intermediate between in vivo and in vitro human metabolic enzyme induction studies.

Repopulation of the immunosuppressed retrorsine-treated infant rat liver with human hepatocytes

BACKGROUND

We previously generated humanized chimeric mice by transplanting h-hepatocytes into the livers of the diseased-liver transgenic mouse model with immunodeficient background. These mice with livers mostly replaced by human (h) hepatocytes have been proved to be useful for research on drug metabolism and toxicity and on intrahepatic pathogens such as hepatitis. However, their small body size prohibited collecting sufficient biological samples and made surgical manipulation difficult, which motivated us to produce humanized larger animal(s) bearing h-hepatocytes.

METHODS

Fischer 344 (F344) rats at 2 weeks of age were administrated with hepatotoxin retrorsine (RS) and then transplanted with syngeneic F344 rat (r)- or h-hepatocytes via the portal vein. The hosts were injected daily with FK506 immunosuppressant. The livers were harvested periodically for determining donor-cell replacement ratios and compared with those of the humanized chimeric mice, and liver-specific mRNA and protein expressions by immunohistochemistry and reverse-transcription PCR.

RESULTS

RS treatment of infant rats inhibited hepatocyte proliferation, resulting in decreased liver weight and megalocytic changes in hepatocytes. R-hepatocytes transplanted into RS-treated rats engrafted into and repopulated the liver at ratios of 16.4 ± 6.7% and 48.3 ± 29.3% at 3 and 6 weeks after transplantation, respectively. H-hepatocytes also engrafted into the rat liver and showed a repopulation ratio of 2.5 ± 1.5% at 3 weeks post-transplantation, which was comparable to the ratio in the humanized chimeric mouse model at least until 3 weeks. Propagated h-hepatocytes in the rat liver expressed hepatocyte-specific mRNA and proteins at least 3 weeks after transplantation.

CONCLUSIONS

Xenogeneic hepatocytes were able to engraft rat liver and grow well therein for at least 3 weeks post-transplantation in rats when immunosuppression was combined appropriately with liver injury at comparable levels to the well-characterized humanized chimeric mouse model.

Generation and characterization of severe combined immunodeficiency rats

Severe combined immunodeficiency (SCID) mice, the most widely used animal model of DNA-PKcs (Prkdc) deficiency, have contributed enormously to our understanding of immunodeficiency, lymphocyte development, and DNA-repair mechanisms, and they are ideal hosts for allogeneic and xenogeneic tissue transplantation. Here, we use zinc-finger nucleases to generate rats that lack either the Prkdc gene (SCID) or the Prkdc and Il2rg genes (referred to as F344-scid gamma [FSG] rats). SCID rats show several phenotypic differences from SCID mice, including growth retardation, premature senescence, and a more severe immunodeficiency without "leaky" phenotypes. Double-knockout FSG rats show an even more immunocompromised phenotype, such as the abolishment of natural killer cells. Finally, xenotransplantation of human induced pluripotent stem cells, ovarian cancer cells, and hepatocytes shows that SCID and FSG rats can act as hosts for xenogeneic tissue grafts and stem cell transplantation and may be useful for preclinical testing of new drugs.

Petersen's hernia as a complication of bariatric surgery: CT findings

Referrals for bariatric surgery have currently increased due to the need for more effective interventions in the management of severely obese patients. The Roux-en-Y gastric bypass is currently one of the preferred procedures, and internal hernias are the main causes of late postoperative complication. Petersen's hernia is a less common finding in most published papers compared to transmesocolic hernia, however, it seems to be increasing in incidence (in our service, eight cases which have been tomographic diagnosed in 2 years, were confirmed by laparoscopic surgery). The clinical findings are not specific, usually with abdominal pain, associated or not with abdominal distention and vomiting. In this context, imaging exams have an important role in the early diagnosis and surgery of this condition, with multislice computed tomography being the most accurate method. The aim of this pictorial essay is to the demonstrate the main CT findings associated with Petersen's hernia in patients who underwent Roux-en-Y gastric bypass.

The changing pattern of referral in acute kidney injury

BACKGROUND

Acute kidney injury (AKI) is not only managed by nephrologists, but also by several other subspecialists. The referral rate to nephrologists and the factors influencing it are unknown.

AIMS

To determine the referral rate, factors affecting referral and outcomes across the spectrum of AKI in a population based study.

METHODS

We identified all patients with serum creatinine concentrations ≥150 µmol/l (male) or ≥130 µmol/l (female) over a 6-month period. AKI was defined according to the RIFLE classification (risk, injury, failure, loss, end stage renal disease [ESRD]). Clinical information and outcomes were obtained from each patient's case records.

RESULTS

A total of 562 patients were identified as having AKI (incidence 2147 per million population/year [pmp/y]). One hundred and sixty-four patients (29%) were referred to nephrologists-referral rate 627 pmp/y. Forty-nine percent of patients whose serum creatinine rose to >300 µmol/l were referred compared with 22% in our previous study of 1997. Forty-eight patients required renal replacement therapy-incidence 184 pmp/y in comparison to 50 pmp/y in our previous study of 1997. Patients had higher odds of referral if they were male, of younger age and were in the F category of the RIFLE classification. Patients had lower odds of referral if they had multiple co-morbid conditions or if they were managed in a hospital without a nephrology service.

CONCLUSION

There has been a significant rise in the referral rate of patients with AKI to nephrologists but even during our period of study only one-third of such patients were being referred. With rising incidence and increased awareness, the referral rate will certainly rise putting a significant burden on the nephrology services.

Growth hormone-dependent pathogenesis of human hepatic steatosis in a novel mouse model bearing a human hepatocyte-repopulated liver

Clinical studies have shown a close association between nonalcoholic fatty liver disease and adult-onset GH deficiency, but the relevant molecular mechanisms are still unclear. No mouse model has been suitable to study the etiological relationship of human nonalcoholic fatty liver disease and human adult-onset GH deficiency under conditions similar to the human liver in vivo. We generated human (h-)hepatocyte chimeric mice with livers that were predominantly repopulated with h-hepatocytes in a h-GH-deficient state. The chimeric mouse liver was mostly repopulated with h-hepatocytes about 50 d after transplantation and spontaneously became fatty in the h-hepatocyte regions after about 70 d. Infusion of the chimeric mouse with h-GH drastically decreased steatosis, showing the direct cause of h-GH deficiency in the generation of hepatic steatosis. Using microarray profiles aided by real-time quantitative RT-PCR, comparison between h-hepatocytes from h-GH-untreated and -treated mice identified 14 GH-up-regulated and four GH-down-regulated genes, including IGF-I, SOCS2, NNMT, IGFLS, P4AH1, SLC16A1, SRD5A1, FADS1, and AKR1B10, respectively. These GH-up- and -down-regulated genes were expressed in the chimeric mouse liver at lower and higher levels than in human livers, respectively. Treatment of the chimeric mice with h-GH ameliorated their altered expression. h-Hepatocytes were separated from chimeric mouse livers for testing in vitro effects of h-GH or h-IGF-I on gene expression, and results showed that GH directly regulated the expression of IGF-I, SOCS2, NNMT, IGFALS, P4AH1, FADS1, and AKR1B10. In conclusion, the chimeric mouse is a novel h-GH-deficient animal model for studying in vivo h-GH-dependent human liver dysfunctions.

Hepatic hyperplasia associated with discordant xenogeneic parenchymal-nonparenchymal interactions in human hepatocyte-repopulated mice

Liver mass is optimized in relation to body mass. Rat (r) and human (h) hepatocytes were transplanted into liver-injured immunodeficient mice and allowed to proliferate for 3 or 11 weeks, respectively, when the transplants stopped proliferating. Liver/body weight ratio was normal throughout in r-hepatocyte-bearing mice (r-hep-mice), but increased continuously in h-hepatocyte-bearing mice (h-hep-mice), until reaching approximately three times the normal m-liver size, which was considered to be hyperplasia of h-hepatocytes because there were no significant differences in cell size among host (mouse [m-]) and donor (r- and h-) hepatocytes. Transforming growth factor-beta (TGF-beta) type I receptor, TGF-beta type II receptor, and activin A type IIA receptor mRNAs in proliferating r-hepatocytes of r-hep-mice were lower than in resting r-hepatocytes (normal levels) and increased to normal levels during the termination phase. Concomitantly, m-hepatic stellate cells began to express TGF-beta proteins. In stark contrast, TGF-beta type II receptor and activin A type IIA receptor mRNAs in h-hepatocytes remained low throughout and m-hepatic stellate cells did not express TGF-beta in h-hep-mice. As expected, Smad2 and 3 translocated into nuclei in r-hep-mice but not in h-hep-mice. Histological analysis showed a paucity of m-stellate cells in h-hepatocyte colonies of h-hep-mouse liver. We conclude that m-stellate cells are able to normally interact with concordant r-hepatocytes but not with discordant h-hepatocytes, which seems to be at least partly responsible for the failure of the liver size optimization in h-hep-mice.

Increased sensitivity to sparsely ionizing radiation due to excessive base excision in clustered DNA damage sites inEscherichia coli

PURPOSE

In order to clarify the cellular processing and repair mechanisms for radiation-induced clustered DNA damage, we examined the correlation between the levels of DNA glycosylases and the sensitivity to ionizing radiation in Escherichia coli.

MATERIALS AND METHODS

The lethal effects of gamma-rays, X-rays, alpha-particles and H2O2 were determined in E. coli with different levels of DNA glycosylases. The formation of double-strand breaks by post-irradiation treatment with DNA glycosylase was assayed with gamma-irradiated plasmid DNA in vitro.

RESULTS

An E. coli mutM nth nei triple mutant was less sensitive to the lethal effect of sparsely ionizing radiation (gamma-rays and X-rays) than the wild-type strain. Overproduction of MutM (8-oxoguanine-DNA glycosylase), Nth (endonuclease III) and Nei (endonulease VIII) increased the sensitivity to gamma-rays, whereas it did not affect the sensitivity to alpha-particles. Increased sensitivity to gamma-rays also occurred in E. coli overproducing human 8-oxoguanine-DNA glycosylase (hOgg1). Treatment of gamma-irradiated plasmid DNA with purified MutM converted the covalently closed circular to the linear form of the DNA. On the other hand, overproduction of MutM conferred resistance to H2O2 on the E. coli mutM nth nei mutant.

CONCLUSIONS

The levels of DNA glycosylases affect the sensitivity of E. coli to gamma-rays and X-rays. Excessive excision by DNA glycosylases converts nearly opposite base damage in clustered DNA damage to double-strand breaks, which are potentially lethal.

Engraftment of human hepatocytes in the livers of rats bearing bone marrow reconstructed with immunodeficient mouse bone marrow cells

BACKGROUND

Previously, we created, a chimeric mouse (humanized mouse), a severe combined immunodeficiency (SCID) mouse whose liver was >90% repopulated with human (h)-hepatocytes, which are useful for the testing of drug metabolism and toxicity, as well as a hepatitis B virus and hepatitis C virus-susceptible animal model. However, their small body size and small total blood volume limited the utilization for analytical purposes, which led us to develop a method to create a chimeric rat bearing h-hepatocyte-repopulated liver.

METHODS

F344 nude rats devoid of T cells were irradiated with X-rays and injected with bone marrow cells (BMCs) from SCID mice (m(SCID)). The rate of replacement with m(SCID)-BMCs was evaluated by two-color flow cytometry analysis of peripheral blood mononuclear cells (PBMCs). After m(SCID)-BMCs repopulated the host bone marrow (BM), the rats were treated with retrorsine, partially hepatectomized (PHx), and transplanted with 5 x 10(6) h-hepatocytes isolated from the chimeric mice. h-Albumin (h-Alb) concentrations in the host blood and the expression levels of protein and mRNA of hepatocyte differentiation markers in the h-hepatocytes were evaluated by ELISA, immunostaining, and reverse transcription-PCR, respectively.

RESULTS

The m(SCID)-BMCs successfully repopulated the rats, the percentage of mouse cells reaching 94% among host (r(nudeF344)) PBMCs at 4 weeks after m-BMC transplantation. h-Hepatocytes isolated from the chimeric mice were transplanted to the liver of the m(SCID)-BMC-repopulated rats. The engrafted h-hepatocytes expressed h-Alb and h-cytochrome P450 (CYP) subtypes and survived showing normal phenotypes until at least 3 weeks post-h-hepatocytes transplantation (h-HPCT). However, the blood concentrations of h-Alb declined at 4 weeks post-HPCT, concomitant with the emergence of both r(nudeF344)- and m(SCID)-macrophages, suggesting the rejection of h-hepatocytes due to the activation of macrophages.

CONCLUSION

We developed a novel method to create a rat that bears the liver engrafted with h-hepatocytes, utilizing a rat with the BM composed of m(SCID)-BMCs as a host. This h-hepatocyte-bearing rat will be a valuable model for studying the immunologic mechanisms involved in xenogeneic transplantation and for generating rats with higher rates of repopulation with h-hepatocytes.

GH enhances proliferation of human hepatocytes grafted into immunodeficient mice with damaged liver

We investigated effects of human (h) GH on the proliferation of h-hepatocytes that had been engrafted in the liver of albumin enhancer/promoter driven-urokinase plasminogen activator transgenic/severe combined immunodeficiency disease (uPA/SCID) mice (chimeric mice). The h-hepatocytes therein were considered to be deficient in GH, because hGH receptor (hGHR) is unresponsive to mouse GH. Actually, hIGF-1 was undetectable in chimeric mouse sera. The uPA/SCID mice were transplanted with h-hepatocytes from a 6-year (6Y)-old donor, and were injected with recombinant hGH (rhGH). rhGH stimulated the repopulation speed of h-hepatocytes; and up-regulated hIGF-1, human signal transducers and activators of transcription (hSTAT) 3, and cell cycle regulatory genes such as human forkhead box M1, human cell division cycle 25A, and human cyclin D1. To confirm the reproducibility of these effects of rhGH, similar experiments were run using h-hepatocytes from a 46-year (46Y)-old donor. rhGH similarly enhanced their repopulation speed and up-regulated the expression of the above-tested genes, especially hIGF-1 and hSTAT1. The extent of the enhancement by rhGH was much less than that in 6Y-hepatocyte-chimeric mice most probably due to the difference in GHR expression levels between the two donors. In conclusion, this study clearly demonstrated that rhGH stimulates the proliferation of h-hepatocytes in vivo.

Coordination of fore and hind leg stepping in cats on a transversely-split treadmill

To gain insight into the mechanism of coordination of stepping in the fore and hind legs of quadrupeds, we examined the kinematics of leg movements and the motor patterns in fore and hind leg flexor muscles in decerebrate walking cats when the two pairs of legs stepped on separate treadmills running at different speeds. When the front treadmill was slowed progressively from 0.6 to 0.3 m/s with the rear treadmill running at 0.6 m/s, the rate of stepping in both the fore and hind legs decreased and a 1:1 stepping ratio was maintained. The decrease in the rate of stepping in the hind legs was due primarily to an increase in the duration of the swing phase. Slowing the speed of the rear treadmill while keeping the front treadmill speed at 0.6 m/s decreased the rate of stepping of the hind legs, but had relatively little influence on the average rate of stepping in the forelegs. In this situation stepping in the fore and hind legs was uncoupled and the time of stepping in one hind leg relative to the ipsilateral foreleg progressively shifted during a walking sequence. Analysis of the timing of electromyographic (EMG) recordings from flexor muscles of the hip and elbow joints yielded insight into the neuronal mechanisms underlying the asymmetry in slowing either the front or rear treadmill. We propose that ipsilateral pattern generating networks are asymmetrically coupled via descending inhibitory pathways and an ascending excitatory pathway. We discuss how the characteristics of these linkages are functionally appropriate for establishing the normal timing of stepping in the hind and forelegs during slow walking.

A Role for Hip Position in Initiating the Swing-to-Stance Transition in Walking Cats

In this investigation, we obtained data that support the hypothesis that afferent signals associated with hip flexion play a role in initiating the swing-to-stance transition of the hind legs in walking cats. Direct evidence came from observations in walking decerebrate cats. Assisting the flexion of the hip joint during swing advanced the onset of activity in ankle extensor muscles, and this advance was strongly correlated with a reduction in the duration of hip flexor muscle activity. The hip angle at the time of onset of the flexion to extension transition was similar during assisted and unassisted steps. Additional evidence for the hypothesis that sensory signals related to hip flexion are important in regulating the swing-to-stance transition came from four normal animals trained to walk in a variety of situations designed to alter the coordination of movements at the hip, knee, and ankle joints during the swing phase. Although there were exceptions in some tasks and preparations, the angle of the hip joint at the time of onset of extensor activity was generally less variable than that of the knee and ankle joints. We also found no clear relationships between the angle of the limb and body axes, or the length of the limb axis, and the time of onset of extensor activity. Finally, there were no indications that the stretching of ankle extensor muscles during swing was a factor in regulating the transition from swing-to-stance.

Recruitment of gastrocnemius muscles during the swing phase of stepping following partial denervation of knee flexor muscles in the cat

In walking cats, the biarticular medial and lateral gastrocnemius (MG-LG) muscles act to produce extension and flexion torques at the ankle and knee, respectively, and they usually display only one burst of activity beginning just before ground contact and ending near the end of the stance phase. Currently, the MG-LG muscles are considered to function primarily to control extension movements around the ankle joint during the stance phase. However, their flexion action at the knee means that they have the capacity to regulate rotations at the knee, but this role has not yet been clearly defined. Following partial denervation of the other muscles that normally act to flex the knee during swing, we observed that the MG-LG muscles, but not the Soleus muscle (a pure ankle extensor), often generated strong bursts of activity during early swing. These bursts were enhanced following mechanical stimulation of the paw, and they were especially prominent when the leg trailed over an object. They were absent when the leg led over an object. During treadmill walking the swing-related bursts in MG and LG had little influence on ankle flexion at the beginning of swing, but they were associated with slowing of ankle flexion when the leg trailed over an object. We hypothesized that the recruitment of these bursts functions to partially compensate for the reduction in knee torque resulting from the denervation of other knee flexors. Consistent with this hypothesis was our finding that the magnitude of the swing-related activity in the MG-LG muscles was linearly correlated to the extent of the knee flexion and to the peak angular velocity of knee flexion, and that the timing of the bursts was similar to that in the denervated muscles prior to denervation. Our findings suggest that an excitatory pathway exists from the flexor half-center of the central pattern-generating network to MG-LG motoneurons, and that this pathway is strongly regulated by central and/or peripheral signals.

Near completely humanized liver in mice shows human-type metabolic responses to drugs

Human hepatocytes were transplanted into urokinase-type plasminogen activator-transgenic SCID mice (uPA/SCID mice), which are immunodeficient and undergo liver failure. The transplanted cells were characterized in terms of their in vivo growth potential and functions. The human hepatocytes progressively repopulated the murine host liver. However, the recipients died when the replacement index (RI) of the human hepatocytes exceeded 50%. The hosts (chimeric mice) survived at RI >50% when treated with a drug that has anti-human complement factor activity, and these mice developed livers with RI values as high as 96%. In total, 36 chimeric mice were generated, and the rate of successful engraftment was as high as 92%. The yield of chimeric mice with RI >70% was 32%. The human hepatocytes in the murine host liver expressed mRNAs for a variety of human cytochrome P450 (hCYP) subtypes, in a manner that was similar to the donor liver. The mRNAs for hCYP3A4 and hCYP1A1/2 were induced in the liver in a CYP type-specific manner when the mice were treated with rifampicin and 3-methylcholanthrene, respectively. These results indicate that human hepatocytes that propagate in mice retain their normal pharmacological responses. We conclude that the chimeric mouse developed in the present study is a useful model for assessing the functions and pharmacological responses of human hepatocytes.

Recombination repair pathway in the maintenance of chromosomal integrity against DNA interstrand crosslinks

DNA interstrand crosslinks (ICL) present a major threat to cell viability and genome integrity. In eukaryotic cells, the ICLs have been suggested to be repaired by a complex process involving Xpf/Ercc1-mediated endonucleolytic incision and homologous recombination (HR). However, the entire feature of the ICL tolerating mechanism is still poorly understood. Here we studied chromosome aberrations (CA) and sister chromatid exchanges (SCE) by the use of the crosslinking agent mitomycin C (MMC), in chicken DT40 cells with the HR genes disrupted by targeted replacement. The disruption of the Rad54, Rad51B, Rad51C, Rad51D, Xrcc2 and Xrcc3 genes resulted in a dramatic reduction of spontaneous and MMC-induced SCEs. Interestingly, while HR-deficient cells were hypersensitive to cell killing by MMC, MMC-induced CAs were also suppressed in the HR-deficient cells except for Rad51D-, Xrcc2- and Xrcc3-deficient cells. These observations indicate that DNA double strand breaks (DSB) at stalled replication forks and those arising as repair intermediates present strong signals to cell death but can be tolerated by the HR repair pathway, where Rad54, Rad51B and Rad51C have an initiative role and repair can be completed by their paralogs Rad51D, Xrcc2 and Xrcc3. The impairment of the HR pathway, which otherwise leads to cell death, may be somewhat substituted by an alternative mechanism such as the Mre11/Rad50/Nbs1 pathway, resulting in reduced frequencies of SCEs and CAs.

Radiation-induced apoptosis in the scid mouse spleen after low dose-rate irradiation

PURPOSE

To elucidate the process of radioadaptation, the role of DNA-PK activity was examined using the scid mouse defective in DNA-PKcs.

MATERIALS AND METHODS

The induction of apoptosis in the spleens of the C.B-17 Icr scid mouse and the parental mouse was studied after chronic irradiation with gamma-rays at 1.5 Gy (0.001 Gy min(-1) for 25 h) followed by challenge irradiation with X-rays at 3.0 Gy (1.0 Gy min(-1) for 3 min).

RESULTS

When the wild-type mouse was previously exposed to chronic irradiation (1.5 Gy) at a low dose-rate (0.001 Gy min(-1)), apoptosis induced by acute irradiation (3.0 Gy, 1.0 Gy min(-1)) was significantly suppressed, especially in the splenic white pulp. There was no change by acute irradiation after chronic irradiation in the scid mouse, although an effect was detected in the spleen after acute irradiation alone.

CONCLUSIONS

These data suggest that DNA-PK activity might play a major role in the radioadaptive response following pre-irradiation at a low dose-rate.

Bipedal locomotion by the normally quadrupedal Japanese monkey, M. Fuscata: strategies for obstacle clearance and recovery from stumbling

This study explored how the normally quadrupedal Japanese monkey adjusts to treadmill perturbations, when trained to walk bipedally. The monkey was required to use the left hindlimb to clear an obstacle that was fixed on the left side of a treadmill belt. The monkey either cleared the obstacle (CL: cleared locomotion), or stumbled over it (SL: stumbled locomotion). For CL, it changed its left hind limb's kinematics according to the obstacle's height and position relative to the left foot. In SL, the monkey used a "defensive posture", which included a rapid lowering of the right foot and forelimb movements, to stabilize the perturbed posture and thereby prevent falling. Then, with powerful extensions of its lower limb joints, the monkey raised its center-of-mass to the appropriate level for continuation of normal bipedal walking. The results show that M. Fuscata recruited both anticipatory and reactive neural mechanisms to accommodate to the obstacle.

High frequency of deletions at the hypoxanthine-guanine phosphoribosyltransferase locus in an ataxia-telangiectasia lymphoblastoid cell line irradiated with gamma-rays

The molecular nature of gamma-ray-induced mutations at the hypoxanthine-guanine phosphoribosyltransferase (HPRT) locus in an ataxia-telangiectasia (A-T) lymphoblastoid cell line was investigated. Twelve of 15 gamma-ray-induced HPRT-deficient mutants showed deletions. Eight of them had lost the entire HPRT gene, one showed a 1.9-kb deletion, and three had deletions of about 40-150 base pairs. Of the eight mutants that lost the entire gene, five had also lost both DXS79 and DXS86, flanking markers of the HPRT locus. The spectrum of mutations induced by gamma-irradiation in the A-T cells showed a high frequency of deletions in comparison with that in a control cell line, WIL2-NS. Sequence analysis of breakpoint junctions in four mutants revealed that three of them had junctions between short identical sequences at each breakpoint, leaving one copy at the junction. These results suggest that non-homologous end-joining is the major mechanism for deletion formation in A-T cells.

Radiation response of apoptosis in C57BL/6N mouse spleen after whole-body irradiation

PURPOSE

Primary conditioning low dose irradiation suppresses the molecular responses against secondary challenge high dose irradiation; this phenomenon has been termed the radioadaptive response. The mechanism of the radioadaptive response is not yet clear. This study was undertaken to elucidate the radiation response of apoptosis in mouse spleen after whole-body irradiation.

MATERIALS AND METHODS

The induction of apoptosis was analysed in the spleens of C57BL/6N mice after chronic irradiation with gamma-rays at 1.5 Gy (0.001 Gy/min for 25 h) followed by challenge irradiation with X-rays at 3.0Gy (1 Gy/min).

RESULTS

Accumulation of p53 and Bax, and the induction of apoptosis were observed dose-dependently in mouse spleen 12 h after acute irradiation at a high dose-rate. However, it was found that there was significant suppression of the accumulation of p53 and Bax, and induction of apoptosis 12 h after challenge irradiation at 3.0Gy at a high dose-rate following chronic preirradiation at 1.5Gy at a low dose-rate. In addition, the combination of pre-irradiation at 1.5Gy at a high dose-rate and challenge irradiation at 3.0Gy at a high dose-rate could not suppress the accumulation of p53 and Bax or the induction of apoptosis.

CONCLUSIONS

Chronic pre-irradiation at a low dose-rate suppressed Bax-mediated apoptosis. These findings suggest that the radioadaptive response in mouse spleen may be due to a suppression of p53-mediated apoptosis.

Stereoselective synthesis of the axially chiral A-B ring system of vancomycin utilizing a planar chiral arene chromium complex

[reaction: see text] The axial biaryl ring system of vancomycin was stereoselectively synthesized by utilizing a planar chiral tricarbonyl(arylhalide)chromium complex. Both enantiomers of the planar chiral (arylbromide)chromium complexes, (+)-9 and ent-(-)-9, can be stereoselectively transferred to an absolutely identical key intermediate 23 for the vancomycin A-B ring system by the diastereoselective Suzuki-Miyaura cross-coupling reaction as key step.

Neonatal thrombocytosis resulting from the maternal use of non-narcotic antischizophrenic drugs during pregnancy

Neonatal thrombocytosis can result from maternal narcotic drug abuse. The case of a male infant is reported who was born to a woman with schizophrenia treated with non-narcotic psychotropic drugs during pregnancy; he developed severe prolonged thrombocytosis. The platelet count reached 1310 x 10(9)/l on day 15. This thrombocytosis persisted for three months. The patient was treated with dipyridamole. A bone marrow aspirate showed normal myeloid and erythroid precursors with an increased number of megakaryocytes. Plasma concentrations of interleukin 6 and thrombopoietin were suppressed. No obvious complications from the thrombocytosis occurred, and the platelet count fell to within the upper limit of normal after 3 months of age. This case indicates that thrombocytosis may occur in infants born to mothers treated with non-narcotic psychopharmaceutical drugs during pregnancy. The thrombocytosis in this case may have been induced by factors other than interleukin 6 or thrombopoietin.

[Development of corneal storage medium--second report. Examination of human cornea]

PURPOSE

To develop and evaluate by histological methods a new corneal storage medium with a simple formula.

METHODS

We compared a corneal storage medium which contained minimum essential medium and 2.5% chondroitin sulfate (molecular weight 27,500), pH 7.33, osmolality 320 mOsm/kg with OPTISOL-GS. Paired human donor eyes provided by the Lions Eye Bank of Oregon were stored in a moist chamber until the experiment. A cornea with scleral rim was excised and stored in OPTISOL-GS, and its fellow cornea was stored in the test medium for 5, 10, or 14 days at 4 degrees C. Histological examination of corneal endothelial cells was done by both scanning electron microscopy and transmission electron microscopy.

RESULTS

On days 5 and 10, there was no significant difference in histological findings between corneas stored in OPTISOL-GS and those in the test medium. Both corneal groups developed degenerative changes with the increase of storage time, but their histological findings were similar for both storage media. On day 14, corneal endothelial cells showed marked degeneration of intracellular organelles such as a swelling of mitochondria in both media.

CONCLUSION

Human corneas stored in the test medium for 14 days maintained their structure as well as those in OPTISOL-GS. This shows that the newly developed corneal storage medium composed can be used for medium-term corneal storage.

Thiolated dermal bovine collagen as a novel support for bioactive substances--conjugation with lysozyme

Thiol groups were introduced to dermal bovine collagen (DBC) by the reaction with gamma-thiobutyrolactone. Thiolated DBC reacted with 2-pyridyl disulfide group introduced to lysozyme to form DBC-lysozyme conjugate through disulfide bridge. The enzymatic activity of freshly prepared conjugate was almost unchanged during ten consecutive runs over one month. The DBC-lysozyme conjugate showed the maximum activity at pH 6.3, on the contrary, that of native lysozyme was pH 9.0. Thermal stability of lysozyme was enhanced by the conjugation with DBC. The present results showed that the conjugation using thiolated collagen could be one of the useful alternative approaches to modify collagen with bioactive molecules.

[Development of corneal storage medium--first report. Examination of rabbit cornea]

PURPOSE

To develop and evaluate a new corneal storage medium with a simple formula by histological methods.

METHODS

We compared two corneal storage media, containing minimum essential medium (MEM) and 2.5% chondroitin sulfate, pH 7.33 and osmolality of 320 mOsm/kg, to OPTISOL-GS. The differences in the two media were the molecular weight (MW) and source of chondroitin sulfate. MW of Medium I was 27,500 and MW of Medium II was 33,700. A cornea with scleral rim obtained from a Japanese white rabbit was stored in either Medium I or Medium II and the fellow cornea was stored in OPTISOL-GS for 7 or 14 days at 4 degrees C. Histological examination of corneal endothelial cells was performed both by scanning electron microscopy and by transmission electron microscopy.

RESULTS

At day 7, there was no significant difference in histological findings among the rabbit corneas stored in OPTISOL-GS, Medium I, or Medium II. At day 14, corneas stored in OPTISOL-GS or Medium I showed similar histological findings. In Medium II, endothelial cells showed marked degeneration.

CONCLUSION

The results of experiments with rabbit cornea indicated that OPTISOL-GS and Medium I could preserve endothelial cellular structure better than Medium II. The difference between Medium I and Medium II was only the MW of the chondroitin sulfate used. The MW may be an important factor to determine suitable chondroitin sulfate for developing a corneal storage medium.

Novel mutations of the FANCG gene causing alternative splicing in Japanese Fanconi anemia

Fanconi anemia (FA), an autosomal recessive disorder characterized by a progressive pancytopenia associated with congenital anomalies and high predisposition to malignancies, is a genetically and clinically heterogeneous disease. At least eight complementation groups (FA-A to FA-H) have been identified. Previously, we studied mutations of the FANCA gene, responsible for FA-A, and found pathogenic mutations in 12 of 15 unclassified Japanese FA patients. Here, we further studied an additional 5 FA patients for sequence alterations of the FANCA gene and found pathogenic mutations in 2 of them. We further analyzed mutations of the FANCC and FANCG genes, responsible for FA-C and FA-G, respectively, in the remaining 6 FA patients. Although there was no alterations in the FANCC gene in these 6 patients, two novel mutations of the FANCG gene, causing aberrant RNA splicing, were detected in 2 FA patients. One was a base substitution from G to C of the invariant GT dinucleotides at the splice donor site of intron 3, resulting in the skipping of exon 3, as well as the skipping of exons 3 and 4. The other was a base substitution from C to T in exon 8, creating a nonsense codon (Q356X). This mutation resulted in the exclusion of a sequence of 18 nucleotides containing the mutation from the mRNA, without affecting the splicing potential of either the authentic or the cryptic splice donor site. Collectively, 14 of the 20 unclassified Japanese FA patients belong to the FA-A group, 2 belong to the FA-G group, and none belongs to the FA-C group.

The FANCA gene in Japanese Fanconi anemia: reports of eight novel mutations and analysis of sequence variability

Fanconi anemia (FA), an autosomal recessive disorder characterized by a progressive pancytopenia associated with congenital anomalies and high predisposition to malignancies, is a genetically and clinically heterogeneous disease. At least eight complementation groups (FA-A to FA-H) have been identified with their relative prevalence varying among the ethnical backgrounds. Recently, responsible genes, FANCA and FANCC, have been cloned. This report describes mutations of the FANCA gene, which we studied by direct sequencing of cDNA with confirmation on genomic DNA in 15 unclassified Japanese FA patients. A total of 19 sequence alterations were identified, of which 10 (six missense and four silent alterations) were likely to be nonpathogenic polymorphism. The remaining nine alterations, of which eight were novel mutations, were assumed to be pathogenic and consisted of two missense mutations and seven mutations resulting in truncation of gene product, demonstrating a wide allelic heterogeneity. The pathogenic mutations were found in 12 patients (80%); they were either homozygous or compound heterozygous in 10 patients, apparently heterozygous in two patients and none in three patients. We conclude that the sequence variability is intrinsic to the FANCA gene and that the relative prevalence of the FA-A subtype is unusually high in Japanese FA patients.

Stimulation of the beta(2) integrin, alpha(M)beta(2), triggers tyrosine phosphorylation and cellular degranulation on human eosinophils

Activation of human eosinophils by specific extracellular stimuli triggers the cellular degranulation response. Because cellular adhesion is critical for this eosinophil degranulation, we have tested the hypothesis that ligation of the beta(2) integrin, alpha(M)beta(2) (Mac-1, CD11b/CD18), leads to intracellular signaling events that contribute to the eosinophil activation response. Recently, we found that engagement of beta(2) integrin using two different approaches, such as cell adhesion induced by IL-5 or direct ligation of alpha(M)beta(2), triggered tyrosine phosphorylation of Cbl, the product of the c-cbl proto-oncogene, paxillin, a cytoskeletal protein, an unidentified 115-kD protein, and subsequent cellular degranulation. The results of this study indicate that engagement of alpha(M)beta(2) on eosinophils triggers an intracellular signaling cascade leading to cellular degranulation. Tyrosine phosphorylation of Cbl, paxillin, and a 115-kD protein may play important roles in adhesion-dependent cellular functions of eosinophils.

Expression of T-cadherin (CDH13, H-Cadherin) in human brain and its characteristics as a negative growth regulator of epidermal growth factor in neuroblastoma cells

In the present study, we first examined the expression of T-cadherin in human CNS by northern blot analysis, immunohistochemical staining, and in situ hybridization. Northern blot analysis demonstrated expression of T-cadherin in human adult cerebral cortex, medulla, thalamus, and midbrain. Immunohistochemical staining with a newly generated monoclonal antibody, designated MA-511, revealed strong expression of T-cadherin in neural cell surface membrane and neurites in adult cerebral cortex, medulla oblongata, and nucleus olivaris. Little or no expression of T-cadherin was found in spinal cord. We further examined T-cadherin expression in various developing nervous systems, and found that T-cadherin expression was lower in developing brain than in adult brain. In situ hybridization revealed that neural cells in medulla oblongata and nucleus olivaris, but not in spinal cord, possessed T-cadherin molecules. We transfected T-cadherin-negative TGW and NH-12 neuroblastoma cells with a T-cadherin cDNA-containing expression vector. T-cadherin-expressing neuroblastoma cells lost mitogenic proliferative response to epidermal growth factor. Epidermal growth factor is known to be required for proliferation of neural stem cells. This finding, together with those of the present study, suggests that T-cadherin functions as a negative regulator of neural cell growth.

[Fibrosing alveolitis following Legionella pneumonia]

We reported a case of fibrosing alveolitis following Legionella pneumonia. A 62-year-old man was admitted to our hospital with fever after a visit to a hot spring. Chest X-ray films on admission demonstrated air-space consolidation in the right lower lung. Legionella pneumonia was diagnosed because the patient had elevated serum antibody to Legionella pneumophila serogroup Ia and tested positive for urinary antigen. Although he was initially treated with rifampicin and erythromycin, he experienced drug-induced eruptions. Antibiotic therapy was accordingly changed to clarithromycin, levofloxacin, and minocycline, which together alleviated the patient's clinical symptoms but delayed radiologic regression. Chest X-ray films 2 months after the onset of illness revealed diffuse ground-glass opacities and progressive reduction of volume in the right lung. Long-term corticosteroid treatment was required. Three and half months after disease onset, fever recurred with the appearance of interstitial shadows in the left lung and positive tests for urinary antigen. Increasing the corticosteroid dose resolved the patient's symptoms.

WAF1 accumulation by carbon-ion beam and alpha-particle irradiation in human glioblastoma cultured cells

PURPOSE

There have been no reports about the effects of heavy-ion beams on the expression of the WAF1 gene, although ionizing radiation such as y-rays and X-rays is well known to induce WAF1 (p21/CIP1/sdi1) gene expression in a p53-dependent manner. In the present study, it was examined whether WAF1 accumulation was induced after carbon-ion (C-) beam or alpha-particle irradiation in four glioblastoma cell lines.

MATERIALS AND METHODS

A colony assay for radiosensitivity and Western blot analysis of WAF1 were applied to two human glioblastoma cell lines, A-172 bearing wild-type p53 (wtp53) and T98G bearing mutated p53 (mp53). A-172/neo and A-172/mp53 were transfected with a control vector (containing only a neo selection marker) and a mp53 expression vector respectively.

RESULTS

The amount of WAF1 increased markedly after X-ray irradiation in A-172 and A-172/neo cells but not in T98G and A-172/mp53 cells. The level of WAF1 reached a plateau at 3-10 h after X-ray irradiation at 5 Gy in A-172 and A-172/neo cells. Likewise, the levels of WAF1 in A-172 and A-172/neo cells reached a plateau at 3-10 h and 6-24 h after C-beam (3.0 Gy) and alpha-particle (4.5 Gy) irradiation respectively. The amount of WAF1 increased markedly in a dose-dependent manner 10 h after X-ray, C-beam or alpha-particle irradiation in A-172 and A-172/neo cells but not in T98G or A-172/mp53 cells. In addition, cell survival assay showed that these cell lines were most sensitive to C-beams, less sensitive to alpha-particles and least sensitive to X-rays at 10% survival. There was no difference in sensitivity among these cell lines against C-beam and alpha-particle irradiation whereas wtp53 cells (A-172 and A-172/neo) were more sensitive to X-rays than mp53 cells (A-172/mp53 and T98G).

CONCLUSIONS

These results indicate that C-beams and alpha-particles induce p53-dependent WAF1 accumulation as well as is the case with X-rays, suggesting that WAF1 protein accumulation may not contribute to cell killing.

Novel prenyltransferase gene encoding farnesylgeranyl diphosphate synthase from a hyperthermophilic archaeon, Aeropyrum pernix. Molecularevolution with alteration in product specificity

Prenyltransferases catalyse sequential condensations of isopentenyl diphosphate with allylic diphosphates. Previously, we reported the presence of farnesylgeranyl diphosphate (FGPP) synthase activity synthesizing C25 isoprenyl diphosphate in Natronobacterium pharaonis which is a haloalkaliphilic archaeon having C20-C25 diether lipids in addition to C20-C20 diether lipids commonly occurring in archaea [Tachibana, A. (1994) FEBS Lett. 341, 291-294]. Recently, it was found that a newly isolated aerobic hyperthermophilic archaeon, Aeropyrum pernix, had only C25-C25 diether lipids, not the usual C20-containing lipids [Morii, H., Yagi, H., Akutsu, H., Nomura, N., Sako, Y. & Koga, Y. (1999) Biochim. Biophys. Acta 1436, 426-436]. In this report, we describe the isoloation from A. pernix of the novel prenyltransferase gene, fgs, encoding FGPP synthase. The protein encoded by fgs was expressed in Escherichia coli as a glutathione S-transferase fusion protein and produced FGPP as a final product. Phylogenetic analysis of fgs with other prenyltransferases revealed that the short-chain prenyltransferase family is divided into three subfamilies: bacterial subfamily I, eukaryotic subfamily II, and archaeal subfamily III. fgs is clearly contained within the archaeal geranylgeranyl diphosphate (GGPP) synthase group (subfamily III), suggesting that FGPP synthase evolved from an archaeal GGPP synthase with an alteration in product specificity.