Measurements of neutrino oscillation parameters from the T2K experiment using 3.6×1021 protons on target

The T2K experiment presents new measurements of neutrino oscillation parameters using 19.7 ( 16.3 ) × 10 20 protons on target (POT) in (anti-)neutrino mode at the far detector (FD). Compared to the previous analysis, an additional 4.7 × 10 20 POT neutrino data was collected at the FD. Significant improvements were made to the analysis methodology, with the near-detector analysis introducing new selections and using more than double the data. Additionally, this is the first T2K oscillation analysis to use NA61/SHINE data on a replica of the T2K target to tune the neutrino flux model, and the neutrino interaction model was improved to include new nuclear effects and calculations. Frequentist and Bayesian analyses are presented, including results on sin 2 θ 13 and the impact of priors on the δ CP measurement. Both analyses prefer the normal mass ordering and upper octant of sin 2 θ 23 with a nearly maximally CP-violating phase. Assuming the normal ordering and using the constraint on sin 2 θ 13 from reactors, sin 2 θ 23 = 0 . 561 - 0.032 + 0.021 using Feldman-Cousins corrected intervals, and Δ m 32 2 = 2 . 494 - 0.058 + 0.041 × 10 - 3 eV 2 using constant Δ χ 2 intervals. The CP-violating phase is constrained to δ CP = - 1 . 97 - 0.70 + 0.97 using Feldman-Cousins corrected intervals, and δ CP = 0 , π is excluded at more than 90% confidence level. A Jarlskog invariant of zero is excluded at more than 2 σ credible level using a flat prior in δ CP , and just below 2 σ using a flat prior in sin δ CP . When the external constraint on sin 2 θ 13 is removed, sin 2 θ 13 = 28 . 0 - 6.5 + 2.8 × 10 - 3 , in agreement with measurements from reactor experiments. These results are consistent with previous T2K analyses.

Changes in cerebrovascular disease-related deaths and their location during the COVID-19 pandemic in Japan

Objective

The COVID-19 pandemic placed an enormous strain on healthcare systems and raised concerns for delays in the management of patients with acute cerebrovascular events. In this study, we investigated cerebrovascular excess deaths in Japan.

Study design

Vital mortality statistics from January 2012 to May 2022 were obtained from the Japanese Ministry of Health, Labour and Welfare.

Methods

Using quasi-Poisson regression models, we estimated the expected weekly number of cerebrovascular deaths in Japan from January 2020 through May 2022 by place of death. Estimates were calculated for deaths in all locations, as well as for deaths in hospitals, in geriatric health service facilities, and at home. The age subgroups of ≥75 and <75 years were also considered. Weeks with a statistically significant excess of cerebrovascular deaths were determined when the weekly number of observed deaths exceeded the upper bound of 97.5% prediction interval.

Results

Excess deaths were noted in June 2021 and became more pronounced from February 2022 onwards. The trend was notable among those aged ≥75 years and for those who died in hospitals. With respect to the location of deaths, the excess was significant in geriatric health services facilities from April 2020 to June 2021, while no evidence of excess hospital deaths was observed during the same period.

Conclusions

Beginning in late 2021, excess cerebrovascular deaths coincided with the spread of the Omicron variant and may be associated with increased healthcare burden. In 2020, COVID-19 altered the geography of cerebrovascular deaths, with fewer people dying in hospitals and more dying in geriatric health service facilities and at home.

TRF2 rescues telomere attrition and prolongs cell survival in Duchenne muscular dystrophy cardiomyocytes derived from human iPSCs

Duchenne muscular dystrophy (DMD) is a severe muscle wasting disease caused by the lack of dystrophin. Heart failure, driven by cardiomyocyte death, fibrosis, and the development of dilated cardiomyopathy, is the leading cause of death in DMD patients. Current treatments decrease the mechanical load on the heart but do not address the root cause of dilated cardiomyopathy: cardiomyocyte death. Previously, we showed that telomere shortening is a hallmark of DMD cardiomyocytes. Here, we test whether prevention of telomere attrition is possible in cardiomyocytes differentiated from patient-derived induced pluripotent stem cells (iPSC-CMs) and if preventing telomere shortening impacts cardiomyocyte function. We observe reduced cell size, nuclear size, and sarcomere density in DMD iPSC-CMs compared with healthy isogenic controls. We find that expression of just one telomere-binding protein, telomeric repeat-binding factor 2 (TRF2), a core component of the shelterin complex, prevents telomere attrition and rescues deficiencies in cell size as well as sarcomere density. We employ a bioengineered platform to micropattern cardiomyocytes for calcium imaging and perform Southern blots of telomere restriction fragments, the gold standard for telomere length assessments. Importantly, preservation of telomere lengths in DMD cardiomyocytes improves their viability. These data provide evidence that preventing telomere attrition ameliorates deficits in cell morphology, activation of the DNA damage response, and premature cell death, suggesting that TRF2 is a key player in DMD-associated cardiac failure.

Abstract P2117: TRF2 Rescues Pathogenic Phenotypes In Duchenne Muscular Dystrophy Cardiomyocytes Derived From Human Induced Pluripotent Stem Cells

Duchenne muscular dystrophy (DMD) is a severe muscle wasting disease caused by the lack of dystrophin. Heart failure, driven by cardiomyocyte death, fibrosis, and the development of dilated cardiomyopathy, is the leading cause of death in DMD patients. Current treatments decrease the mechanical load on the heart; however, these treatments do not address the root cause of dilated cardiomyopathy: loss of cardiomyocytes. Previously, we showed that longer telomeres are protective against dilated cardiomyopathy. Here we investigated the role of telomeres as a target for therapy in DMD cardiomyocytes using human induced pluripotent stem cells (iPSCs) to model the disease. Compared to healthy controls, DMD cardiomyocytes exhibited reduced telomere lengths, cell size, nuclear size, and sarcomere density. The telomere-binding protein, TRF2, is a core component of the shelterin complex, which protects chromosome ends. TRF2 levels are reduced relative to healthy controls in DMD cardiomyocytes. We hypothesized that decreased TRF2 drives telomere attrition in the progression of dilated cardiomyopathy. Our data show that TRF2 overexpression prevented telomere attrition and also rescued deficits in cell size, nuclear size, sarcomere density, and calcium handling. These data highlight the benefits of TRF2 upregulation as a potential gene therapy to delay the onset of dilated cardiomyopathy.

Abstract P2120: Microdystrophin Design Comparisons In Dystrophin-Deficient Cardiomyocytes

Duchenne muscular dystrophy (DMD) is a severe muscle wasting disease caused by the lack of dystrophin. Dilated cardiomyopathy is the leading cause of death in DMD patients. Preclinical data show that smaller versions of dystrophin, called microdystrophins, can ameliorate disease progression. These transgenes, amenable to packaging into adeno-associated virus, have shown to be effective in improving skeletal muscle function; however, the functional benefit of microdystrophins in delaying heart failure is unknown. To identify the design principles that are important for addressing DMD heart dysfunction, three microdystrophin variants currently in clinical trials were tested in cardiomyocytes differentiated from induced pluripotent stem cells (iPSC-CMs) with deficiencies in dystrophin. Previously, we reported that mechanical contraction and calcium handling are impaired in DMD iPSC-CMs. To test the functional benefit of the microdystrophins, we performed traction force microscopy, that provides multiparametric measurements of contraction, and calcium imaging with a ratiometric calcium-binding dye. Our results show a partial rescue of contractile deficits and aberrant calcium handling, underscoring the need for new design variants that address cardiomyocyte dysfunction.

Tamoxifen treatment ameliorates contractile dysfunction of Duchenne muscular dystrophy stem cell-derived cardiomyocytes on bioengineered substrates

Duchenne muscular dystrophy (DMD) is a progressive genetic myopathy that leads to heart failure from dilated cardiomyopathy by early adulthood. Recent evidence suggests that tamoxifen, a selective estrogen receptor modulator widely used to treat breast cancer, ameliorates DMD cardiomyopathy. However, the mechanism of action of 4-hydroxytamoxifen, the active metabolite of tamoxifen, on cardiomyocyte function remains unclear. To examine the effects of chronic 4-hydroxytamoxifen treatment, we used state-of-the-art human-induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) and a bioengineered platform to model DMD. We assessed the beating rate and beating velocity of iPSC-CMs in monolayers and as single cells on micropatterns that promote a physiological cardiomyocyte morphology. We found that 4-hydroxytamoxifen treatment of DMD iPSC-CMs decreased beating rate, increased beating velocity, and ameliorated calcium-handling deficits, leading to prolonged viability. Our study highlights the utility of a bioengineered iPSC-CM platform for drug testing and underscores the potential of repurposing tamoxifen as a therapy for DMD cardiomyopathy.

Excess deaths from COVID-19 in Japan and 47 prefectures from January through June 2021

Objectives

In Japan, several studies have reported no excess all-cause deaths (the difference between the observed and expected number of deaths) during the coronavirus disease 2019 (COVID-19) pandemic in 2020. This study aimed to estimate the weekly excess deaths in Japan's 47 prefectures for 2021 until June 27.

Study design

Vital statistical data on deaths were obtained from the Ministry of Health, Labour and Welfare of Japan. For this analysis, we used data from January 2012 to June 2021.

Methods

A quasi-Poisson regression was used to estimate the expected weekly number of deaths. Excess deaths were expressed as the range of differences between the observed and expected number of all-cause deaths and the 95% upper bound of the one-sided prediction interval.

Results

Since January 2021, excess deaths were observed for the first time in the week corresponding to April 12–18 and have continued through mid-June, with the highest excess percentage occurring in the week corresponding to May 31–June 6 (excess deaths: 1431–2587; excess percentage: 5.95–10.77%). Similarly, excess deaths were observed in consecutive weeks from April to June 2021 in 18 of 47 prefectures.

Conclusions

For the first time since February 2020, when the first COVID-19 death was reported in Japan, excess deaths possibly related to COVID-19 were observed in April 2021 in Japan, during the fourth wave. This may reflect the deaths of non-infected people owing to the disruption that the pandemic has caused.

Increased tissue stiffness triggers contractile dysfunction and telomere shortening in dystrophic cardiomyocytes

Duchenne muscular dystrophy (DMD) is a rare X-linked recessive disease that is associated with severe progressive muscle degeneration culminating in death due to cardiorespiratory failure. We previously observed an unexpected proliferation-independent telomere shortening in cardiomyocytes of a DMD mouse model. Here, we provide mechanistic insights using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Using traction force microscopy, we show that DMD hiPSC-CMs exhibit deficits in force generation on fibrotic-like bioengineered hydrogels, aberrant calcium handling, and increased reactive oxygen species levels. Furthermore, we observed a progressive post-mitotic telomere shortening in DMD hiPSC-CMs coincident with downregulation of shelterin complex, telomere capping proteins, and activation of the p53 DNA damage response. This telomere shortening is blocked by blebbistatin, which inhibits contraction in DMD cardiomyocytes. Our studies underscore the role of fibrotic stiffening in the etiology of DMD cardiomyopathy. In addition, our data indicate that telomere shortening is progressive, contraction dependent, and mechanosensitive, and suggest points of therapeutic intervention.

Trend change of the transmission route of COVID-19-related symptoms in Japan

OBJECTIVES

The Japanese prime minister declared a state of emergency on April 7 2020 to combat the outbreak of coronavirus disease 2019 (COVID-19). This declaration was unique in the sense that it was essentially driven by the voluntary restraint of the residents. We examined the change of the infection route by investigating contact experiences with COVID-19-positive cases.

STUDY DESIGN

This study is a population-level questionnaire-based study using a social networking service (SNS).

METHODS

To assess the impact of the declaration, this study used population-level questionnaire data collected from an SNS with 121,375 respondents (between March 27 and May 5) to assess the change in transmission routes over the study period, which was measured by investigating the association between COVID-19-related symptoms and (self-reported) contact with COVID-19-infected individuals.

RESULTS

The results of this study show that the declaration prevented infections in the workplace, but increased domestic infections as people stayed at home. However, after April 24, workplace infections started to increase again, driven by the increase in community-acquired infections.

CONCLUSIONS

While careful interpretation is necessary because our data are self-reported from voluntary SNS users, these findings indicate the impact of the declaration on the change in transmission routes of COVID-19 over time in Japan.

Abstract 522: Impaired Inside-out Force Transmission in Hipsc-cardiomyocyte Model of Duchenne Muscular Dystrophy Cardiomyopathy

Duchenne Muscular Dystrophy (DMD) is a lethal X-chromosome linked disease that affects ~1:3500 boys and culminates in heart failure in early adulthood. DMD results from >200 possible dystrophin mutations. The lack of dystrophin disrupts the anchoring of the sarcomere to the extracellular matrix (ECM), impairing cardiomyocyte function and cardiac contraction. With disease progression, the heart tissue stiffness increases as fibrosis progresses and a dilated cardiomyopathy phenotype develops. We hypothesize that disease progression accelerates because of a positive feedback loop involving fibrotic stiffening and mechanosensing. Our preliminary results show that single human-derived pluripotent stem cell (hiPSC) cardiomyocytes (CMs) with DMD mutations have a dramatically reduced ability to produce force compared to isogenic controls on stiffer substrates mimicking a fibrotic state, but not on soft healthy substrates. This stiffness-dependent contractile deficiency correlates with an increase in reactive oxygen species (ROS) and mitochondrial dysfunction, as well as other markers of cellular stress response and senescence. Here, we ask how stiffness affects the progression of DMD cardiomyopathy and aim to draw a link between the lack of dystrophin and force production deficiency in hiPSC-CMs with or without DMD mutations in an isogenic background. Using a novel assay and algorithm, we simultaneously measure extracellular force production by traction force microscopy (TFM) and single sarcomere dynamics (SSD) in single hiPSC-CMs adhered onto ECM micropatterns on top of a hydrogel of stiffness matching that of healthy (~10kPa) or fibrotic (~35kPa) tissue. We induce the single hiPSC-CMs to adopt a physiologic elongated 1:7 aspect ratio using microcontact printing of ECM protein. Using this platform, we determine how the lack of dystrophin impacts sarcomere architecture, sarcomere contractility, and force generation in the etiology of DMD cardiac disease.

The relationship between fever rate and telework implementation as a social distancing measure against the COVID-19 pandemic in Japan

Objectives

On March 28, the Japanese government decided on the “Basic Policies for Novel Coronavirus Disease Control” and called on the public to thoroughly implement social distancing measures (i.e., behavioral restrictions to limit the frequency and intensity of human contact), especially telework.

Methods

We used population-level questionnaire data from a social networking service (SNS), with 275,560 respondents from March 5 to April 6, to evaluate the relationship between telework implementation and the presence of a fever (body temperature higher than 37.5 °C) within 1 month as a surrogate indicator of COVID-19 infection, by occupation type and age-group.

Results

Among company employees, statistical significance was identified in the 15- to 29-year and 30- to 59-year age-groups, showing higher fever rates in the non-teleworker group (for the 15- to 29-year age-group, non-teleworkers: 7.64%; teleworkers: 6.45%; P = 0.02; for the 30- to 59-year age-group, non-teleworkers: 3.46%; teleworkers: 3.14%; P = 0.02).

Conclusions

Telework remains a controversial topic in Japan as the government called for emergency measures. Although caution is warranted in interpreting our findings because our data are limited to the voluntary SNS users, they will be essential to push forward with more measures to promote social distancing measures in the midst of Japan's current tense political climate.

Abstract 477: Role of Telomere Dysfunction in Duchenne Muscular Dystrophy Cardiomyopathy

Duchenne muscular dystrophy (DMD) is a devastating X-linked genetic disorder that affects 1 in 3500 males. Characterized by progressive muscle degeneration that culminates in respiratory failure and dilated cardiomyopathy, DMD is caused by a lack of dystrophin, a protein that provides structural support between the sarcomeric cytoskeleton and the extracellular matrix. Loss of dystrophin leads to a leaky plasma membrane, contractile stress, and disruption of cellular homeostasis. However, the molecular mechanism that eventually leads to cell death remains to be explored. Recently, the Blau lab discovered a pathogenic link between DMD cardiomyopathy and telomere dysfunction. While mdx mice that lack functional dystrophin do not exhibit dilated cardiomyopathy as in human patients, when crossed with mTR mice that lack the RNA component of telomerase (TERC), mdx mice with “humanized” telomere lengths fully manifested the severe muscle wasting and cardiac failure seen in patients. Notably, the longer telomeres, characteristic of mice, appear to be cardioprotective. Importantly, we observed telomere shortening in cardiomyocytes, but not other cell types, of DMD patients compared to age-matched controls. Preliminary data suggests that contractile stress due to the lack of dystrophin leads to a pathogenic feed-forward loop which ultimately culminates in cardiomyocyte cell death. Using human iPS cells derived from DMD patients, we have modeled telomere shortening and aspects of cardiomyocyte dysfunction characteristic of DMD, including aberrant calcium transients, mechanical stress, and arrhythmia. By comparing cardiomyocytes derived from DMD iPS cells with those from CRISPR-corrected isogenic controls on patterned bioengineered hydrogel platforms of varying stiffness, we can study the role of fibrotic stiffening in the myocardium in the premature demise of DMD cardiomyocytes. Pinpointing the early molecular events that trigger the pathogenic feed-forward loop will provide strategies for intervention to ameliorate DMD cardiomyopathy.

Reprogramming cell fate with artificial transcription factors

Transcription factors (TFs) reprogram cell states by exerting control over gene regulatory networks and the epigenetic landscape of a cell. Artificial transcription factors (ATFs) are designer regulatory proteins comprised of modular units that can be customized to overcome challenges faced by natural TFs in establishing and maintaining desired cell states. Decades of research on DNA-binding proteins and synthetic molecules has provided a molecular toolkit for ATF design and the construction of genome-scale libraries of ATFs capable of phenotypic manipulation and reprogramming of cell states. Here, we compare the unique strengths and limitations of different ATF platforms, highlight the advantages of cooperative assembly, and present the potential of ATF libraries in revealing gene regulatory networks that govern cell fate choices.

Synthetic transcription elongation factors license transcription across repressive chromatin

The release of paused RNA polymerase II into productive elongation is highly regulated, especially at genes that affect human development and disease. To exert control over this rate-limiting step, we designed sequence-specific synthetic transcription elongation factors (Syn-TEFs). These molecules are composed of programmable DNA-binding ligands flexibly tethered to a small molecule that engages the transcription elongation machinery. By limiting activity to targeted loci, Syn-TEFs convert constituent modules from broad-spectrum inhibitors of transcription into gene-specific stimulators. Here we present Syn-TEF1, a molecule that actively enables transcription across repressive GAA repeats that silence frataxin expression in Friedreich's ataxia, a terminal neurodegenerative disease with no effective therapy. The modular design of Syn-TEF1 defines a general framework for developing a class of molecules that license transcription elongation at targeted genomic loci.

Genome-wide Mapping of Drug-DNA Interactions in Cells with COSMIC (Crosslinking of Small Molecules to Isolate Chromatin)

The genome is the target of some of the most effective chemotherapeutics, but most of these drugs lack DNA sequence specificity, which leads to dose-limiting toxicity and many adverse side effects. Targeting the genome with sequence-specific small molecules may enable molecules with increased therapeutic index and fewer off-target effects. N-methylpyrrole/N-methylimidazole polyamides are molecules that can be rationally designed to target specific DNA sequences with exquisite precision. And unlike most natural transcription factors, polyamides can bind to methylated and chromatinized DNA without a loss in affinity. The sequence specificity of polyamides has been extensively studied in vitro with cognate site identification (CSI) and with traditional biochemical and biophysical approaches, but the study of polyamide binding to genomic targets in cells remains elusive. Here we report a method, the crosslinking of small molecules to isolate chromatin (COSMIC), that identifies polyamide binding sites across the genome. COSMIC is similar to chromatin immunoprecipitation (ChIP), but differs in two important ways: (1) a photocrosslinker is employed to enable selective, temporally-controlled capture of polyamide binding events, and (2) the biotin affinity handle is used to purify polyamide-DNA conjugates under semi-denaturing conditions to decrease DNA that is non-covalently bound. COSMIC is a general strategy that can be used to reveal the genome-wide binding events of polyamides and other genome-targeting chemotherapeutic agents.

Serial magnetic resonance imaging study of posterior cruciate ligament reconstruction or augmentation using hamstring tendons

PURPOSE

The purpose of this study was to analyze serial changes in the magnetic resonance imaging (MRI) signals of autograft hamstrings single bundle posterior cruciate ligament (PCL) reconstruction and the effects of remnant preservation (augmentation).

MATERIAL AND METHODS

Twenty-two isolated PCL injuries were arthroscopically reconstructed or augmented with hamstring tendons. MRI scans were obtained at 3, 6, and 12 months, and prior to the second-look arthroscopy (average 20.7 months). The patients were divided into 2 groups by remnant preservation: five PCL reconstructions after PCL remnant resection (Group Rec) (23%), and 17 reconstructions preserving the remnant (Group Aug) (77%). The 22 patients were also divided in two groups depending on the location of the PCL tear. There were 9 knees with proximal tear (Type P) (41%) and 13 knees with distal tear (Type D) (59%). The signal intensity and fiber continuity of 4 zones (proximal, middle, distal intra-articular and tibial tunnel zones) were evaluated by the Mariani score.

RESULTS

The average MRI evaluation score gradually increased from 6 months through the final MRI. The intra-articular part of the graft exhibited slower maturation (12 months - final scan) as compared with the tibial tunnel (6-12 months). The distal zone underwent better maturation than the proximal or middle zones at all points. In the proximal zone, the score for Group Aug was significantly higher than Group Rec. In the proximal zone, the Type D score with a proximally-preserved remnant was significantly higher than Type P without a proximal remnant.

CONCLUSIONS

The hamstring tendons require more than 1 year to achieve low-signal intensity. PCL remnant has a beneficial effect on the maturation of the hamstring graft.

LEVEL OF EVIDENCE IV

therapeutic case series.

Mapping polyamide-DNA interactions in human cells reveals a new design strategy for effective targeting of genomic sites

Targeting the genome with sequence-specific synthetic molecules is a major goal at the interface of chemistry, biology, and personalized medicine. Pyrrole/imidazole-based polyamides can be rationally designed to target specific DNA sequences with exquisite precision in vitro; yet, the biological outcomes are often difficult to interpret using current models of binding energetics. To directly identify the binding sites of polyamides across the genome, we designed, synthesized, and tested polyamide derivatives that enabled covalent crosslinking and localization of polyamide-DNA interaction sites in live human cells. Bioinformatic analysis of the data reveals that clustered binding sites, spanning a broad range of affinities, best predict occupancy in cells. In contrast to the prevailing paradigm of targeting single high-affinity sites, our results point to a new design principle to deploy polyamides and perhaps other synthetic molecules to effectively target desired genomic sites in vivo.

Proprioceptive function after isolated single-bundle posterior cruciate ligament reconstruction with remnant preservation for chronic posterior cruciate ligament injuries

INTRODUCTION

Posterior cruciate ligament (PCL) reconstruction using the remnant preserving technique may contribute to improved postoperative posterior stability, graft healing, and proprioception recovery. Although there have been several reports on remnant preserving PCL reconstruction, no study has yet evaluated the proprioceptive functions before and after PCL reconstruction with remnant preservation. The purpose of this study is to retrospectively evaluate the clinical outcomes and proprioceptive function after isolated single-bundle PCL reconstruction with remnant preservation for chronic PCL injuries.

HYPOTHESIS

Isolated single-bundle PCL reconstruction with remnant preservation surgery for chronic PCL injuries provides satisfactory clinical outcomes and good recovery of the proprioceptive function.

METHODS

Nineteen patients who had undergone isolated single-bundle PCL reconstruction with remnant preservation for chronic PCL injuries were followed up for more than 2 years. The posterior laxity was measured by the gravity sag view, stress radiography and the KT-2000 knee arthrometer. The proprioceptive function was defined as the threshold to detect passive motion (TTDPM).

RESULTS

The average Lysholm score significantly improved from 63.7±13.2 preoperatively to 94.4±4.6 at final follow-up. The postoperative posterior laxity significantly improved. Regarding TTDPM, there were no significant differences between the preoperative score and the score at every given time point, regardless of the starting angles and the moving directions of the knees.

CONCLUSIONS

The proprioceptive function, defined as TTDPM, is maintained after single-bundle PCL reconstruction with remnant preservation, and the postoperative clinical scores and posterior laxity significantly improve.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Influence of trunk muscle co-contraction on spinal curvature during sitting cross-legged

In Asia, many activities of daily living (ADL) are performed while sitting cross-legged on the floor. This sitting posture rotates the pelvis in a more dorsal direction and lumbar lordosis is more flattened than while sitting on a chair. Sitting cross-legged induces a greater load on the intervertebral discs and spine, especially when in a slumped position that is known to increase disc pressure even more and to aggravate chronic low back pain (CLBP). Therefore, it is very important to instruct Asian people about the correct sitting posture. In addition, it is known that co-contraction of the deep spine-stabilizing muscles enhances lumbar segmental stability and the sacroiliac joint. However, little is known about the influence of co-contraction of the trunk deep muscles on spinal curvature while sitting cross-legged on the floor. The purpose of this study was to compare EMG (electromyographic) activity of the trunk muscles while slump cross-legged sitting with that during co-contraction of the trunk muscles and to investigate how this co-contraction influences spinal curvature. Ten healthy male volunteers (21.7 +/- 2.5 years old) without CLBP participated in the study. Bipolar surface electrodes were attached to the rectus abdominis, the obliquus externus abdominis, the obliquus internus abdominis, the lower back extensor muscles (L3) and the multifidus on the right side. EMG signals were continuously recorded while slump sitting cross-legged and during co-contraction of the trunk muscles. They were amplified, band-pass filtered, digitized and stored by a data acquisition system. The average muscle activity values over the five-second sample for each sitting posture were normalized to maximal voluntary contractions (%MVC). While the subjects performed both sitting postures, the curvature of the spine was measured using a skin-surface and hand-held device, the "Spinal Mouse". More significant activities of the trunk muscles, with the exception of the rectus abdominis, were observed during co-contraction of the trunk muscles than while slump sitting cross-legged. The co-contraction of the trunk muscles resulted in significantly less thoracic and lumbar curvature and more sacral angle than while slump sitting cross-legged. The results of this study indicated that co-contraction of the trunk muscles while sitting cross-legged could bring about the correct thoracic and lumbar curvature, and effectively stabilize the lumbopelvic region, and decrease focal stress on passive structures.

Adaptive changes in control of the head while lifting ten times

We often observe when workers lift objects, they tend to move their heads upward and back. Their movement may be an efficient habit, but little is known about control of the head while lifting. Our primary aim was to investigate the hypothesis that several repetitive liftings would lead to an increase in neck extension. Fifteen healthy male volunteers (20.9 +/- 0.8 years old) were asked to lift a case 10 times without instructions about the starting posture or lifting technique. Motion data and electromyography (EMG) signals were continuously recorded. The lifting time, angles of joints, and distance between the case and the malleolus lateralis at the moment of lifting were calculated from the motion data. EMG signals of the initial 1/10 phase of each lifting time were averaged and normalized to maximal voluntary contractions(% AEMG), and the mean frequencies were calculated by wavelet transform analysis. One-way analysis of variance and post hoc analysis were performed with Dunnett's test (p < 0.05). The cervical extension angle significantly increased, and the distance between the case and the malleolus lateralis significantly decreased for the later lifting times. The % AEMG of the gluteus maximus and the biceps femoris significantly increased for the later lifting times. A moving upward and back of the weight of the head, a decrease in the distance between the body and the case, and increases in tension of the hip extensor muscles could facilitate a righting movement to maintain balance. Therefore, paying attention to head control may be efficient while lifting.

Mitigation of peroxynitrite-mediated nitric oxide (NO) toxicity as a mechanism of induced adaptive NO resistance in the CNS

During CNS injury and diseases, nitric oxide (NO) is released at a high flux rate leading to formation of peroxynitrite (ONOO(*)) and other reactive nitrogenous species, which nitrate tyrosines of proteins to form 3-nitrotyrosine (3NY), leading to cell death. Previously, we have found that motor neurons exposed to low levels of NO become resistant to subsequent cytotoxic NO challenge; an effect dubbed induced adaptive resistance (IAR). Here, we report IAR mitigates, not only cell death, but 3NY formation in response to cytotoxic NO. Addition of an NO scavenger before NO challenge duplicates IAR, implicating reactive nitrogenous species in cell death. Addition of uric acid (a peroxynitrite scavenger) before cytotoxic NO challenge, duplicates IAR, implicating peroxynitrite, with subsequent 3NY formation, in cell death, and abrogation of this pathway as a mechanism of IAR. IAR is dependent on the heme-metabolizing enzyme, heme oxygenase-1 (HO1), as indicated by the elimination of IAR by a specific HO1 inhibitor, and by the finding that neurons isolated from HO1 null mice have increased NO sensitivity with concomitant increased 3NY formation. This data indicate that IAR is an HO1-dependent mechanism that prevents peroxynitrite-mediated NO toxicity in motor neurons, thereby elucidating therapeutic targets for the mitigation of CNS disease and injury.

Differential sensitivity of oligodendrocytes and motor neurons to reactive nitrogen species: implications for multiple sclerosis

Depending on its concentration, nitric oxide (NO) has beneficial or toxic effects. In pathological conditions, NO reacts with superoxide to form peroxynitrite, which nitrates proteins forming nitrotyrosine residues (3NY), leading to loss of protein function, perturbation of signal transduction, and cell death. 3NY immunoreactivity is present in many CNS diseases, particularly multiple sclerosis. Here, using the high flux NO donor, spermine-NONOate, we report that oligodendrocytes are resistant to NO, while motor neurons are NO sensitive. Motor neuron sensitivity correlates with the NO-dependent formation of 3NY, which is significantly more pronounced in motor neurons when compared with oligodendrocytes, suggesting peroxynitrite as the toxic molecule. The heme-metabolizing enzyme, heme-oxygenase-1 (HO1), is necessary for oligodendrocyte NO resistance, as demonstrated by loss of resistance after HO1 inhibition. Resistance is reinstated by peroxynitrite scavenging with uric acid further implicating peroxynitrite as responsible for NO sensitivity. Most importantly, differential sensitivity to NO is also present in cultures of primary oligodendrocytes and motor neurons. Finally, motor neurons cocultured with oligodendrocytes, or oligodendrocyte-conditioned media, become resistant to NO toxicity. Preliminary studies suggest oligodendrocytes release a soluble factor that protects motor neurons. Our findings challenge the current paradigm that oligodendrocytes are the exclusive target of multiple sclerosis pathology.

Influence of trunk muscle co-contraction on spinal curvature during sitting reclining against the backrest of a chair

Today, many office workers frequently adopt a relaxed or slumped sitting posture for many hours, and often people tend to spend their leisure time reclining against the backrest of a chair while sitting for a long time, as when watching television. While sitting, the pelvis rotates backwardly, and lumbar lordosis is flattened. Simultaneously, the load on the intervertebral discs and spine increases. Sitting in a slumped position is known to increase disc pressure even more, and to aggravate chronic low back pain (CLBP). Therefore, it is very important to teach workers and often people about the correct sitting posture. In addition, it has been recognized that co-contraction of the deep spine-stabilizing muscles enhances lumbar segmental stability and the sacro-iliac joint. However, little is known about the influence of co-contraction of the trunk deep muscles on spinal curvature during sitting reclining against the backrest of a chair. The purpose of this study was to compare the EMG (electromyographic) activity of the trunk muscles during slump sitting with that during co-contraction and to investigate how this cocontraction influences spinal curvature. Ten healthy male volunteers (20.8 +/- 0.8 years old) without CLBP participated in the study. Bipolar surface electrodes were attached to the rectus abdominis, the obliquus externus abdominis, the obliquus internus abdominis, the lower back extensor muscles (L3) and the multifidus on the right side. The EMG signals were continuously recorded during slump sitting and co-contraction of the trunk muscles, reclining against the backrest of chair. They were amplified, band-pass filtered, digitized and stored by a data acquisition system. The average muscle activity values over the five-second sample for each sitting posture were normalized to maximal voluntary contractions (%MVC). While the subjects performed both sitting postures, the curvature of the spine was measured using a new skin-surface and hand-held device, the "Spinal Mouse". More significant activities of the trunk muscles, with the exception of the rectus abdominis and the lower back extensor muscles (L3), were observed during co-contraction of the trunk muscles than during slump sitting. The co-contraction of the trunk muscles resulted in significantly less lumbar curvature and more sacral angle than during slump sitting. The thoracic curvature showed no significant change during either sitting posture. The results of this study indicated that co-contraction of the trunk muscles during sitting reclining against the backrest of a chair could bring about the correct lumbar curvature, effectively stabilize the lumbopelvic region, and decrease focal stress on passive structures.

Influences of the position of the head on posture while lifting

In clinical training of some lower back pain patients, teaching them to control their lumbar lordosis during lifting may be difficult. Therefore, another effective method for lifting technique is required. In standing, head cannot move without some compensating postural adjustment. The purpose of this study was to examine the influence of head position on lifting posture. Fourteen healthy male volunteers (22.6 +/- 4.4 years old) lifted a case while maintaining two different head positions; a downward position and an upright position. In the upright position, activities of the latissimus dorsi and vastus lateralis significantly increased, and these of the biceps femoris significantly decreased during the initial 100 msec phase of lifting. There were no differences in the activities of the upper trapezius, lumbar extensor muscles (L3, L5), and obliquus abdominis under the two conditions. There were also no differences in the lumbar angle when the case was lifted. The flexion angles of the hip, knee, and ankle significantly increased, and the lumbar spine moved closer to the case. Lifting posture was influenced by the head position. Advantages included being able to shift loads on the body from the lower back to the legs, to move the lumbar spine closer to the case, and to relatively increase the moment of lumbar extension. The weight of the head as it moved upward and back, and the weight of the rear part of the body as it moved downward and forward helped to maintain balance.

Influence of trunk muscle co-contraction on spinal curvature during sitting for desk work

Nowadays, a lot of office workers are forced to sit at a desk for many hours while doing their jobs. While sitting, the pelvis rotates backwardly, and lumbar lordosis is flattened. At the same time, the load on the intervertebral discs and spine increases. Sitting in a slumped position is known to increase disc pressure even more, and to aggravate chronic low back pain (CLBP). Therefore, it is very important to teach workers about the correct sitting posture. In addition, it has been recognized that co-contraction of the deep spine-stabilizing muscles enhances lumbar segmental stability and the sacro-iliac joint. However, little is known about the influence of co-contraction of the trunk deep muscles on spinal curvature during sitting for while doing desk work. The purpose of this study was to compare EMG (electromyographic) activity of the trunk muscles during slump sitting with that during co-contraction of the trunk muscles and to investigate how this co-contraction influences spinal curvature. Ten healthy male volunteers (21.7 +/- 2.5 years old) without CLBP participated in the study. Bipolar surface electrodes were attached to the rectus abdominis, the obliquus externus abdominis, the obliquus internus abdominis, the lower back extensor muscles (L3) and the multifidus on the right side. EMG signals were continuously recorded during slump sitting and co-contraction of the trunk muscles, simulating a desk work sitting posture; i.e., slightly inclined forward. They were amplified, band-pass filtered, digitized and stored by a data acquisition system. The average muscle activity values over the five-second sample for each sitting posture were normalized to maximal voluntary contractions (%MVC). While the subjects performed both sitting postures, the curvature of the spine was measured using a new skin-surface and hand-held device, the "Spinal Mouse". More significant activities of the trunk muscles, with the exception of the rectus abdominis, were observed during co-contraction of the trunk muscles than during slump sitting The co-contraction of the trunk muscles resulted in significantly less lumbar curvature and more sacral angle than during slump sitting. The thoracic curvature showed no significant change during either sitting posture. The results of this study indicated that co-contraction of the trunk muscles during sitting while doing desk work could bring about the correct lumbar curvature, and effectively stabilize the lumbopelvic region, and decrease focal stress on passive structures.

Electromyographic activity of selected trunk muscles during bicycle ergometer exercise and walking

Recently, active treatment such as exercise has been increasingly advocated for CLBP (chronic low back pain). Specially, exercise to improve fitness has been recommended for the prevention of back injuries. The bicycle ergometer or walking have often been used to improve the fitness of CLBP patients. However, little is known about the activity levels of the trunk muscles during such exercise. In this study, the electromyographic (EMG) activities of the trunk muscles during bicycle ergometer exercises and walking were compared and the load level on these muscles during such exercises was investigated. The present study provides basic information concerning fitness exercise in CLBP patients. Eleven healthy male volunteers (21.7 +/- 2.5 years old) without low back pain participated in the study. Bipolar surface electrodes were attached to the right side of the rectus abdominis, the obliquus externus abdominis and lower back extensor muscles (L3). EMG signals were continuously recorded while walking and during gradual loading exercises and normalized to maximal voluntary contractions (% MVC). One way analysis of variance (ANOVA) was performed on the % MVC from each exercise and walking for each of the three trunk muscle sites (p < 0.05). The rectus abdominis muscle showed activity of about 6% MVC during any grade of exercise and walking and no significant differences were found between these forms of exercise. The obliquus externus abdominis muscle showed about 30% MVC during any grade of exercise and walking, but no significant difference was found between them. The low back muscles showed activity of about 12% MVC while walking, whereas activity level increased as the exercise load using the bicycle ergometer increased. More significant low back muscles activity was observed while walking than during exercises of 25 w and 50 w. The results of this study indicated that exercise using the bicycle ergometer should be useful for maintaining or improving fitness in CLBP patients, because it results in less load on the trunk muscles and relatively more oxygen uptake than walking.

Effect of static stretch on fatigue of lumbar muscles induced by prolonged contraction

Low back pain (LBP) is believed to be the result of fatigue of the back extensor muscles induced by prolonged contraction. Although static stretch has been considered to promote recovery from such muscle fatigue by relaxation, little is known about the effect of stretch on muscle fatigue, especially in the back extensor muscles. The purpose of this study was to investigate the effect of static stretch on prolonged contraction-inducedfatigue of the back extensor muscles using electromyographic (EMG) spectral analysis in ten healthy volunteers. Bipolar surface electrodes were placed on the longissimus and the multifidus muscles. EMG signals were collected during two trials of a Sorensen trunk-holding test for two minutes, with a five-minute rest period between the two trials (control test). All subjects were asked to perform the same trials, with one-minute of static stretch and a four-minute rest period (stretch test). Maintaining the knees toward the chest in supine position resulted in static stretch. The median frequency (MF) was calculated using a spectrum analysis program, and the MF slope over time was computed by linear regression analysis, and normalized with the y-intercept. The decreasing rate of the normalized MF slope between two trials in two tests was compared. The decreasing rate of the normalized MF slope of the second trial was larger than that of the first trial in the control test (p < 0.05), but no significant difference was observed in the stretch test. The results indicated that static stretch had a significant effect on the recovery from fatigue of the back extensor muscles, since it influenced the decreasing rate of the normalized MF slope.

Protein transduction domain of HIV-1 Tat protein promotes efficient delivery of DNA into mammalian cells

The plasma membrane of mammalian cells is one of the tight barriers against gene transfer by synthetic delivery systems. Various agents have been used to facilitate gene transfer by destabilizing the endosomal membrane under acidic conditions, but their utility is limited, especially for gene transfer in vivo. In this article, we report that the protein transduction domain of human immunodeficiency virus type 1 Tat protein (Tat peptide) greatly facilitates gene transfer via membrane destabilization. We constructed recombinant lambda phage particles displaying Tat peptide on their surfaces and carrying mammalian marker genes as part of their genomes (Tat-phage). We demonstrate that, when animal cells are briefly exposed to Tat-phage, significant expression of phage marker genes is induced with no harmful effects to the cells. In contrast, recombinant phage displaying other functional peptides, such as the integrin-binding domain or a nuclear localization signal, could not induce detectable marker gene expression. The expression of marker genes induced by Tat-phage is not affected by endosomotropic agents but is partially impaired by inhibitors of caveolae formation. These data suggest that Tat peptide will become a useful component of synthetic delivery vehicles that promote gene transfer independently of the classical endocytic pathway.

Nuclear targeting of DNA

The nuclear membrane is a tight barrier for cytoplasmic proteins, but nuclear proteins have the intrinsic ability to overcome this barrier by an active signal-mediated process. Specific cytoplasmic carrier proteins have the responsibility to escort these proteins into the nucleus through the nuclear pore. The nuclear membrane is also a tight barrier for exogenous DNA delivered by synthetic vehicles, while many of the karyophilic viruses have a mechanism to actively deliver their genome through the nuclear pore. Virus DNA and RNA cannot move into the nucleus by themselves and require the viral structural proteins for efficient nuclear transport. In this article, we review the recent progress in understanding the mechanism of the nuclear transport of proteins and the virus genome, and discuss the possibility of developing synthetic gene-delivery systems based on these outcomes.

TRF1 is a critical trans-acting factor required for de novo telomere formation in human cells

The duplex telomere repeat (TTAGGG)(n) is an essential cis-acting element of the mammalian telomere, and an exogenous telomere repeat can induce chromosome breakage and de novo telomere formation at the site of a break (telomere seeding). Telomere seeding requires the telomere repeat (TTAGGG)(n) more stringently than does an in vitro telomerase assay, suggesting that it reflects the activity of a critical trans-acting element of the functional telomere, in addition to telomerase. Furthermore, telomere seeding is induced at a frequency fluctuating widely among human cell lines, suggesting variation in the activity of this hypothetical factor among cells. In this study, we investigated the cellular factor(s) required for telomere formation using the frequency of telomere seeding as an index and identified TRF1, one of the telomere repeat binding proteins, as an essential trans-acting factor. The exogenous telomere repeat induces telomere formation at a frequency determined by the availability of TRF1, even in telomerase-negative cells. Our study shows clearly that TRF1 has a novel physiological significance distinct from its role as a regulator of telomere length in the endogenous chromosome. The possible role of TRF1 in cell aging and immortalization is discussed.

A novel strategy for cancer therapy by mutated mammalian degenerin gene transfer

Mammalian degenerin (MDEG) is a member of the amiloride-sensitive sodium ion channel family, and its site-directed active mutant (MDEG-G430F) induces massive Na+ influx into cells, leading to cell ballooning and cell bursting. We attempted a novel therapeutic approach for gastric cancers by transferring MDEG-G430F into cancer cells using tumor-specific promoters. In carcinoembryonic antigen (CEA)-producing gastric cancer cells, the level of cell death observed when MDEG-G430F was used with a CEA promoter was similar to that observed when using a potent nonspecific promoter such as the cytomegalovirus promoter. In an in vivo study, fusogenic liposome complexes containing MDEG-G430F driven by the CEA promoter were injected intraperitoneally into CEA-producing gastric cancer cells in a mouse peritoneal dissemination model. Although all 15 of the control mice were dead by 50 days postinoculation, 13 of the 15 mice treated with MDEG-G430F survived. These results indicate that transferring MDEG-G430F into cancer tissues using tumor-specific promoters can achieve striking and selective cancer cell death irrespective of the transcriptional efficiency of the promoters used in vivo, and suggest that this approach is a promising new strategy for cancer gene therapy.

Effect of toluene inhalation on astrocytes and neurotrophic factor in rat brain

Toluene, an abused substance in Japan, is a neurotoxic chemical that has been shown to have neurobehavioral and electrophysiological effects. In previous work, both acute and chronic effects of toluene on cells have been studied extensively. However, although glial cells are thought to play an important role in the survival of neurons in the brain, the effect of toluene on glial cell function has not yet been characterized. To elucidate this, the effect of toluene inhalation on astrocytes in rat brain was examined. Toluene exposure (1500 ppm for 4 h on 4-10 days) augmented glial fibrillary acidic protein (GFAP) immunoreactivity, particularly in the hippocampus and cerebellum. Quantitative analysis showed that toluene inhalation markedly enhanced GFAP expression in the hippocampus and cerebellum. In both regions, proliferating cell nuclear antigen (PCNA) showed no obvious changes, but glutamine synthetase (GS)-immunoreactive cells were markedly increased by toluene exposure. Thus, the elevation of GFAP expression was induced by astrocyte activation rather than by cell proliferation. If toluene exposure activates astrocytes, astrocytes may play a role in the neurophysiological changes observed in toluene intoxication. A neurotrophic factor, basic fibroblast growth factor (b-FGF) was observed immunohistochemically in the capillary vessel walls in the hippocampus and the cerebellum of toluene-intoxicated rats. Basic-FGF may have induced GFAP expression both in the hippocampus and the cerebellum. So, other neurotrophic factors may affect the difference of GFAP elevation between the hippocampus and the cerebellum. These differences may relate to neurobehavioral function of each brain part after toluene exposure.

Identification and characterization of cell lines with a defect in a post-adsorption stage of Sendai virus-mediated membrane fusion

In the early stage of infection, Sendai virus delivers its genome into the cytoplasm by fusing the viral envelope with the cell membrane. Although the adsorption of virus particles to cell surface receptors has been characterized in detail, the ensuing complex process that leads to the fusion between the lipid bilayers remains mostly obscure. In the present study, we identified and characterized cell lines with a defect in the Sendai virus-mediated membrane fusion, using fusion-mediated delivery of fragment A of diphtheria toxin as an index. These cells, persistently infected with the temperature-sensitive variant Sendai virus, had primary viral receptors indistinguishable in number and affinity from those of parental susceptible cells. However, they proved to be thoroughly defective in the Sendai virus-mediated membrane fusion. We also found that viral HN protein expressed in the defective cells was responsible for the interference with membrane fusion. These results suggested the presence of a previously uncharacterized, HN-dependent intermediate stage in the Sendai virus-mediated membrane fusion.

HSP70 and c-Fos expression of brain stem hypoglossal nucleus in drowning

The brain stem hypoglossal nucleus (HN) is the center of nerves innervating the upper respiratory tract and is related to control of mastication, deglutition, speech and respiration. To elucidate the relationship between asphyxia and the HN, we investigated the change of hypoglossal neurons in cases of hanging, strangulation, smothering, choking, drowning and respiratory failure. Using immunohistochemical techniques, we observed the brain stem HN with antibodies against microtubule-associated protein 2 (MAP2), muscarinic acetylcholine receptor (mAChR), c-fos gene product (c-Fos) and 72 kD heat-shock protein (HSP70). MAP2, a cytoskeletal protein of the neuron, is a marker of neuronal damage. Muscarinic AChR was used as a marker of neuronal membrane and ACh signaling. We employed both HSP70 and c-Fos as markers of stress- or damage-related events. We measured the percentage of immunopositive neurons in total neurons of HN. Drowning produced higher expression of HSP70 and c-Fos than other causes of asphyxia, suggesting that drowning induces more severe damage in HN neurons. Furthermore, it was suspected that neuronal changes in drowning might relate to functions of the HN. These observations indicate that immunohistochemical examination of the brain stem HN could provide useful information for determining the cause of asphyxia.

Target-cell specificity of fusogenic liposomes: membrane fusion-mediated macromolecule delivery into human blood mononuclear cells

Fusogenic liposome, a unique vector prepared by fusing ultraviolet-inactivated Sendai virus and liposome, is known to efficiently deliver content into various animal cells through membrane fusion. In this study, we examined the target-cell specificity of fusogenic liposome (FL)-mediated macromolecule delivery into human blood cells using diphtheria toxin fragment A (DTA) as a probe. Among the peripheral blood mononuclear cells (PBMC), FL was able to deliver its encapsulates into CD14+ monocytes and CD4-/CD8- T-cells, but not into CD19+ B-lymphocytes, CD4+ T-cells or CD8+ T-cells. The susceptibility of human leukemia cell lines to FL was similar to that of PBMC; the order of the reactivity was U937 (monoblastic leukemia)>MOLT4, Jurkat (T-lymphoma)>Daudi, BALL1 (B-lymphoma)>K562 (erythroblastic leukemia). Interestingly, FL showed similar binding activity to all of these leukemia cell lines. These findings indicate that, among blood cells, monocytes, monoblastic leukemia cells, CD4-/CD8- T-cells and T-lymphoma cells are preferable targets for FL-mediated macromolecule delivery. This is the first demonstration of the existence of non-permissive cells against FL. Our results also suggest that some molecules on target-cells other than the binding targets of SV-derived protein may participate in fusion between FL and cells.

Gene delivery systems using the Sendai virus

Fusogenic liposome (FL) is a delivery system that can transfer encapsulated materials into living cells directly through membrane fusion. FL is a promising approach for gene therapy because it can deliver various genetic materials much more efficiently than other non-viral vectors without damaging the cell. FL-mediated gene transfer consists of two independent membrane fusion phenomena; generation of a FL by fusing a Sendai virus (SV) particle with a simple liposome encapsulating DNA, and successive fusion of the FL with cell membrane. The former requires viral F protein but no other special molecule on the liposomal membrane, whereas the latter may require the receptor (sialic acid) and unidentified assistant molecule(s) on the cell membrane. Further analysis suggests that these assistant molecule(s), not the receptor, may control the fusion and govern the cell specificity of FL-mediated delivery. This review has described a detailed analysis of these fusion phenomena and discussed possible applications of FL-mediated gene delivery to human gene therapy.

Gene transfer vectors based on Sendai virus

A gene delivery system is a fundamental technology used in human gene therapy. In order to treat patients suffering from incurable metabolic diseases, we must be able to deliver genes efficiently in situ and induce stable gene expression in non-dividing tissue cells. However, none of the current gene transfer systems (both viral and non-viral) satisfies this goal. In order to develop a novel gene delivery system that is free from the defects of existing gene transfer vectors, we analyzed natural biological phenomena that involve gene transfer and expression, and made artificial components that mimic the functioning of these systems. Our recent results shed light on three major aspects of gene transfer and expression: (1) the direct delivery of DNA into cytoplasm using fusogenic liposomes, (2) the transfer of DNA from cytoplasm to nucleus with a nuclear localization signal, and (3) the stabilization of DNA in the nucleus as an independent replicon. The possible development of a hybrid vector by combining these components is discussed.

Increase in the peripheral lymphocyte populations expressing CD54 (ICAM-1) after hyperthermic isolated limb perfusion in patients with malignant melanoma: an analysis of four cases

The lymphocytes isolated from perfused or non-perfused circulations before, during, and after hyperthermic isolated limb perfusion (HILP) in the four patients with malignant melanoma were analysed for the expression of CD54 (ICAM-1), CD58 (LFA-3), CD4, CD8, HLA class I and class II in order to investigate the mechanism(s) of the activation of such immunocompetent cells as natural killer (NK)-cells or T-lymphocytes by HILP. It was thus found that the lymphocyte populations expressing CD54 increased significantly 1 day after HILP in the four patients examined. The lymphocyte populations expressing CD58 apparently increased. It was also found that the NK-cell and T-lymphocyte activities increased during or after HILP in the present four cases as observed previously in the other melanoma patients. These results indicate that our HILP system may augment the immunological activities through the mechanisms of the induction of CD54 or CD58 expression in the peripheral lymphocytes of the melanoma patients who receive HILP.

[Clinical activity of native valve endocarditis]

We reviewed clinical course and surgical outcome of 31 patients with native valve endocarditis who underwent an operation between 1980 and 1994. In the present study, 15 patients who manifested a neurologic complication associated with endocarditis and/or those who had a periannular abscess were assigned as 'clinical active'. Comparing with non-active group (n = 16), clinical active group included more patients with increased C-reactive protein level and those with histological acute inflammatory reaction on excised valvular tissue. Optimal timing of the operation and surgical procedures for aortic root reconstruction were significant problems in the active group. Actuarial probability of survival at 5 postoperative year was 50.8 and 87.5% in the active and non-active group, respectively. The results suggest our 'clinical activity' is a useful predictor in patients with native valve endocarditis.

Synchronous multicentric development of hepatocellular carcinoma

Recently, the multicentric origin of hepatocellular carcinoma (HCC) has been recognized, but its clinical importance has still not yet been clarified. The histological characteristics of small hyperechoic HCCs coexisting in 44 consecutively resected Japanese patients whose main HCCs were < 5.0 cm in size were studied. Twelve small hyperechoic HCCs were found and classified into the following two groups: eight nodules in seven patients (15.9%) were early-stage HCC, and four nodules in four patients (9.1%) were more advanced HCC. Thus, early-stage HCC comprised 66.7% of the small echogenic HCCs. Eight HCCs detected as small hyperechoic lesions (found in 15.9% of the patients) showed varying degrees of fatty change yet proved to be well differentiated and retained the preexisting liver structure of either associated liver cirrhosis or chronic hepatitis. Moreover, the histologic characteristics of the eight early-stage HCCs were different from those of the main HCCs. In conclusion, approximately 15% of HCCs in Japanese patients may have a synchronous multicentric origin, and small hyperechoic lesions should be carefully evaluated. However, in the United States or other areas where the occurrence of fatty liver is common, that advice for small hyperechoic lesions may be overly cautious.

A valid new approach in treating solitary new lesions after resection of hepatocellular carcinoma

Recent studies have suggested that the appearance of solitary new lesions after a curative resection of hepatocellular carcinoma (HCC) may be closely related to the metachronous multicentric development of HCC. It is therefore extremely important to investigate the histological characteristics of solitary new nodular lesions confirmed to be HCC by an ultrasound (US)-guided needle biopsy. Thirty-five patients with small HCC, < or = 3 cm in diameter, who underwent a curative hepatic resection between 1987 and 1992, were observed for possible recurrence over a period of > or = 1 year. Solitary new lesions confirmed to be HCC were noted in 7 (20.0%) out of 35 cases 10-65 months after operation. All solitary new lesions underwent US-guided needle biopsy, and a histological examination of the biopsy specimen was performed. All seven solitary new lesions were then classified into the following two groups according to the histologic differentiation of biopsy specimens and were found to consist of five well-differentiated HCCs (71.4%) and two moderately differentiated HCCs (28.6%). Three of the five well-differentiated HCCs were accompanied by varying degrees of fatty changes. These morphologic observations suggest that approximately 70% of the solitary new lesions confirmed to be HCC after a curative resection of small HCC may thus be related to the metachronous multicentric origin of HCC. However, it is difficult to estimate the exact incidence of such cases. As a result, curative treatment may sometimes be feasible, even when treating solitary new lesions after resection of HCC. Therefore, we can better evaluate such solitary new nodular lesions after a resection of HCC by means of a histologic evaluation using US-guided needle biopsy.

Early stage hepatocellular carcinoma detected during intraoperative ultrasonography

OBJECTIVES

Recently, it has been recognized that there are increasing incidences of hepatocellular carcinoma (HCC) multicentricity. Thus, intraoperatively detected hepatic lesions that were once thought to be metastatic lesions now need to be carefully reexamined to determine whether they are true metastatic lesions or the multicentric development of HCC.

METHODS

We investigated the histological characteristics of small nodular lesions detected during intraoperative ultrasonography in 33 consecutive patients with small HCC who underwent laparotomy at our institution.

RESULTS

Fourteen nodular lesions were found incidentally in 10 of 33 patients (30.3%), and were classified into the following three groups: 11 nodules in nine patients (27.3%) were HCC, two nodules in two patients (6.1%) were hemangioma, and one nodule in one patient (3.0%) was a large regenerative nodule. HCC therefore comprised 78.6% of the intraoperatively detected nodular lesions. Of the 11 HCCs, six were hyperechoic, four were hypoechoic, and one was isoechoic. Five (83.3%) of six small hyperechoic HCCs and two (50.0%) of four hypoechoic HCCs were well differentiated and retained their preexisting liver structure. These findings closely coincide with the characteristics of early stage HCC. Thus, early stage HCC comprised 63.6% of the intraoperatively detected HCC cases.

CONCLUSIONS

A certain proportion of small satellite HCCs detected during intraoperative ultrasonography in patients with small HCC, which were previously thought to be metastatic lesions from the main HCC, may instead be early stage HCCs. Such findings would also support the concept of the multicentric development of HCC. Approximately 60% of all small HCC cases detected intraoperatively may be early stage HCC. As a result, it is predicted that the emergence of HCC is either multicentric or unicentric, with early intrahepatic spread, although the former seems to be more common.

[A case of early gastric cancer with Virchow's node metastasis, effectively treated by high dose of UFT]

We report a case of early gastric cancer with Virchow's node metastasis. The patient underwent partial gastrectomy and postoperative immunochemotherapy using MMC, 5'-DFUR and PSK, which reduced the Virchow's node. Three years after surgery, we found metastases to the left subclavicular and axillary nodes other than the Virchow's node. Then UFT was administered orally at 600 mg/day, and the metastatic nodes diminished, then vanished. The patient is alive nearly five years after surgery.

Multistep, multicentric, and simultaneous development of hepatocellular carcinoma

We resected a multiple hepatocellular carcinoma (HCC) which contained portal tracts, showed evidence of an early multistep condition, and a multicentric development of HCC which progressed simultaneously. A preoperative working examination revealed a tumor in S5 of the liver, which was 2.5 cm in diameter. In addition, a "nodule-in-nodule" appearance was seen on the ultrasonographic imaging. At intraoperative ultrasonography, an additional two HCCs were detected. At histologic examination of the resected specimen, the main nodule showed a nodule-in-nodule appearance. In the outer nodule, there was a well-differentiated HCC, while the portal tracts remained. The less-differentiated HCC grew in the inner nodule and was replacing the well-differentiated HCC in the outer nodule. These findings suggests morphological transition in the early stages of the multistep development of HCC. Two additional tumors (1.1 cm and 1.0 cm in diameter) detected at intraoperative ultrasonography proved to be HCCs (grade I) with marked fatty change, and with portal tracts remaining within both the HCCs. Furthermore, both of the HCCs retained their preexisting liver structure. These histologic findings coincided with the characteristics of the early stage HCC, whereas the coexistence of early stage HCCs suggests the multicentric development of HCC. Distortion, compression, and invasion of the portal tracts may appear as the tumor grows, thereby evoking an increasing risk of metastasis via the portal tracts. Therefore, the early diagnosis and treatment of HCC before the portal tracts disappear, when 1.5 cm in size or less, may be very important for surgeons and diagnosticians, as an effective curative resection may be feasible.