Impact of deep learning on radiologists and radiology residents in detecting breast cancer on CT: a cross-vendor test study

AIM

To investigate the effect of deep learning on the diagnostic performance of radiologists and radiology residents in detecting breast cancers on computed tomography (CT).

MATERIALS AND METHODS

In this retrospective study, patients undergoing contrast-enhanced chest CT between January 2010 and December 2020 using equipment from two vendors were included. Patients with confirmed breast cancer were categorised as the training (n=201) and validation (n=26) group and the testing group (n=30) using processed CT images from either vendor. The trained deep-learning model was applied to test group patients with (30 females; mean age = 59.2 ± 15.8 years) and without (19 males, 21 females; mean age = 64 ± 15.9 years) breast cancer. Image-based diagnostic performance of the deep-learning model was evaluated with the area under the receiver operating characteristic curve (AUC). Two radiologists and three radiology residents were asked to detect malignant lesions by recording a four-point diagnostic confidence score before and after referring to the result from the deep-learning model, and their diagnostic performance was evaluated using jackknife alternative free-response receiver operating characteristic analysis by calculating the figure of merit (FOM).

RESULTS

The AUCs of the trained deep-learning model on the validation and test data were 0.976 and 0.967, respectively. After referencing with the result of the deep learning model, the FOMs of readers significantly improved (reader 1/2/3/4/5: from 0.933/0.962/0.883/0.944/0.867 to 0.958/0.968/0.917/0.947/0.900; p=0.038).

CONCLUSION

Deep learning can help radiologists and radiology residents detect breast cancer on CT.

Clinical characteristics and outcomes of pheochromocytoma crisis: a literature review of 200 cases

PURPOSE

Pheochromocytoma crisis is a life-threatening endocrine emergency that requires prompt diagnosis and treatment. Because of its rarity, sudden onset, and lack of internationally uniform and validated diagnostic criteria, pheochromocytoma crisis remains to be fully clarified. Therefore, we aimed to describe the clinical characteristics and outcomes of pheochromocytoma crisis through a literature review.

METHODS

We performed a systematic literature search of PubMed/MEDLINE database, Igaku-Chuo-Zasshi (Japanese database), and Google Scholar to identify case reports of pheochromocytoma crisis published until February 5, 2021. Information was extracted and analyzed from the literature that reported adequate individual patient data of pheochromocytoma crisis in English or Japanese. Cases were also termed as pheochromocytoma multisystem crisis (PMC) if patients had signs of hyperthermia, multiple organ failure, encephalopathy, and labile blood pressure.

RESULTS

In the 200 cases of pheochromocytoma crisis identified from 187 articles, the mean patient age was 43.8 ± 15.5 years. The most common symptom was headache (39.5%). The heart was the most commonly damaged organ resulting from a complication of a pheochromocytoma crisis (99.0%), followed by the lungs (44.0%) and the kidney (21.5%). PMC accounted for 19.0% of all pheochromocytoma crisis cases. After excluding 12 cases with unknown survival statuses, the mortality rate was 13.8% (26/188 cases). Multivariable logistic regression analysis revealed that nausea and vomiting were significantly associated with a higher mortality rate.

CONCLUSION

Pheochromocytoma can present with different symptomatology, affecting different organ systems. Clinicians should be aware that patients with nausea or vomiting are at a higher risk of death because of pheochromocytoma crisis.

129I/127I and Δ14C records in a modern coral from Rowley Shoals off northwestern Australia reflect the 20th-century human nuclear activities and ocean/atmosphere circulations

Radionuclides produced by 20th-century human nuclear activities from 1945 (e.g., atmospheric nuclear explosions and nuclear-fuel reprocessing) made significant impacts on earth's surface environments. Long-lived shallow-water corals living in tropical/subtropical seas incorporate the anthropogenically-produced radionuclides, including ¹²⁹I and ¹⁴C, into their skeletons, and provide time series records of the impacts of nuclear activities. Here, we present ¹²⁹I/¹²⁷I and Δ¹⁴C time series records of an annually-banded modern coral skeleton from Rowley Shoals, off the northwestern coast of Australia, in the far eastern Indian Ocean. The ¹²⁹I/¹²⁷I and Δ¹⁴C records, covering the period 1930s-1990s, exhibit distinct increases caused by the nuclear activities, and their increasing profiles are clearly different from each other. The first distinct ¹²⁹I/¹²⁷I increase occurs from 1955 to 1959, followed by a decrease in 1960-1963. The increase is probably due to US atmospheric nuclear explosions in Bikini and Eniwetok Atolls in 1954, 1956 and 1958. The ¹²⁹I produced in those nuclear tests would be transported by the North Equatorial Current, a portion of which passes through the Indonesian Throughflow and then reaches Rowley Shoals. This initial increase from 1955 is, however, absent in the Δ¹⁴C record, which shows a distinct increase from 1959 and its peak around the mid-1970s, followed by a gradual decrease. This absence and the 4-year-delayed Δ¹⁴C increase are likely due to dilution of explosion-produced ¹⁴C with natural carbon (by seawater mixing and air-sea gas exchange) being much more intense than that of explosion-produced ¹²⁹I with natural iodine (by the same processes), suggesting that the ¹²⁹I/¹²⁷I ratio is a more conservative anthropogenic tracer in surface ocean waters, as compared to Δ¹⁴C. The second ¹²⁹I/¹²⁷I increase is contemporaneous with a rapid Δ¹⁴C increase during 1964-1967, followed by a rapid ¹²⁹I/¹²⁷I decrease in 1968-1969; the increases can be ascribed to very large atmospheric nuclear explosions conducted in the former Soviet Union in 1961-1962. The third ¹²⁹I/¹²⁷I increase appears between 1969/1970 and 1992, which can be attributed to airborne ¹²⁹I released from nuclear-fuel reprocessing facilities in Europe, the former Soviet Union and the US. The coral ¹²⁹I/¹²⁷I and Δ¹⁴C time series records, combined with previous studies, enhance our understanding of the behavior of anthropogenic ¹²⁹I and ¹⁴C in the global ocean and atmosphere.

Regulation of nursing professionals in Cambodia: strategies to overcome underpinning challenges

AIMS

To elucidate (i) the challenges and constraints in the development and implementation of the regulatory framework for nursing professionals in Cambodia and (ii) the specific strategies adopted to address the challenges experienced in Cambodia.

INTRODUCTION

The health workforce will be critical to achieving the health-related and wider Sustainable Development Goals in the years up to 2030.

BACKGROUND

In 2006, the countries of the Association of Southeast Asian Nations signed a Mutual Recognition Arrangement in relation to nursing services in the region with the main aim of facilitating the mobility of nursing professionals between countries. To ensure the competency of the health workforce and the quality and safety of health services, member states are required to establish an appropriate regulatory framework.

METHODS

This is a qualitative descriptive study. Eighteen key informant interviews were conducted in Cambodia in 2018. Walt and Gilson's policy analysis model was applied to organize and synthesize the data.

FINDINGS

Major challenges were identified such as conceptual and cultural issues, limited capacity of Cambodian stakeholders and an unstandardized system with limited coordination.

DISCUSSION

In Cambodia, the nursing regulatory environment has expanded greatly over the last decade. Strategies adopted were 'political leadership', optimal utilization of 'outsider's capacity', strengthening 'insider's capacity', and 'dedicated consultation and collaboration and consensus building' involving all players.

IMPLICATIONS FOR NURSING AND HEALTH POLICIES

Policymakers in similar resource-limited countries could apply and adapt similar strategic efforts when formulating and implementing health policies, legislation and regulations. 'Outsiders', in this case, represented by development partners can play a vital role in the process, but should not be leading the charge. They should be aligned with national priority to support recipient countries. It is imperative for these countries and development partners to invest in increasing the quantity and quality of nursing leaders who can develop and advance regulatory functions.

Evaluation of epithelial and mesenchymal cell markers in canine urinary bladder transitional cell carcinoma

Canine transitional cell carcinoma (cTCC) is the most common malignant tumour in the urinary bladder: it is highly invasive and exhibits metastatic characteristics. Inflammation is also strongly related to cTCC. Epithelial tumours often exhibit a mesenchymal cell phenotype during tumour invasion and metastasis owing to epithelial-mesenchymal transition (EMT), which is often induced in chronic inflammation. The aim of this retrospective study was to investigate the expression of epithelial and mesenchymal cell markers in tumour cells and to evaluate its relationship with prognosis of cTCC. In this study, 29 dogs with cTCC who underwent surgical treatment were enrolled. Clinical parameters were reviewed using medical records. Tissue expression of epithelial and mesenchymal markers was evaluated by immunohistochemical analysis. The association between the expression of mesenchymal cell markers and clinical parameters, including prognosis, was statistically examined. In five normal bladder tissues used as controls, no expression of mesenchymal markers was observed, except for one tissue that expressed fibronectin. Conversely, epithelial tumour cells expressed vimentin and fibronectin in 23/29 and 19/28 cTCC tissues, respectively. Regarding clinical parameters, vimentin score in Miniature Dachshunds was significantly higher than those in other dog breeds (P < 0.001). Multivariate survival analyses revealed that age>12 years was related to shorter progression-free survival (P = 0.02). Higher vimentin score, lower fibronectin score, and advanced clinical T stage were significantly correlated with shorter median survival time (P < 0.05). The results of this study indicate that vimentin expression was associated with cTCC progression. Further studies are needed to examine the incidence and relevance of EMT in cTCC.

SS-MIX: A Ministry Project to Promote Standardized Healthcare Information Exchange

Objectives: To promote healthcare information exchange between providers and to allow hospital information systems (HIS) export information in standardized format (HL7 and DICOM) in an environment of widespread legacy systems, which only can export data in proprietary format.

Methods: Through the Shizuoka prefecture EMR project in 2004–2005, followed by the ministry’s SS-MIX project, many software products have been provided, which consist of 1) a standardized storage to receive HL7 v2.5 mes sages of patient demographics, prescription orders, laboratory results, and diagnostic disease in ICD-10, 2) a referral letter creation system, 3) a formatted document creation system, 4) a progress note/nursing record system, and 5) an archive/viewer to incorporate incoming healthcare data CD and allow users to view on HIS terminal. Meanwhile, other useful applications have been produced, such as adverse event reporting and clinical information retrieval. To achieve the above-mentioned objectives, these software products were created and propagated, because users can use these software products, provided that their HIS can export the above information to the standardized storage in HL7 v2.5 format.

Results: In 20 hospitals of Japan, the standardized storage has been installed and some applications have been used. As major HIS vendors are shipping HIS with HL7 export function since 2007, HIS of 594 hospitals in Japan became capable of exporting data in HL7 v2.5 format (as of March 2010).

Conclusions: In high CPOE installation rate (85% in 400+ bed hospitals), though most of them only capable of exporting data in proprietary format, prefecture and ministry projects were effective to promote healthcare information exchange between providers. The standardized storage became an infrastructure for many useful applications, and many hospitals started using them. Ministry designation of proposed healthcare standards was effective so as to allow vendors to conform their products, and users to install them.

Predictors of therapeutic effect of transarterial chemoembolisation using drug-eluting beads for hepatocellular carcinoma

AIMS

To identify predictors of a therapeutic effect after transarterial chemoembolisation using drug-eluting beads (DEB-TACE) for hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Between January 2015 and July 2015, tumour variables and angiographic data were collected for 25 patients (49 target lesions) after they had undergone the DEB-TACE procedure for HCC. The therapeutic effect was evaluated according to the Response Evaluation Criteria in Cancer of the Liver at follow-up dynamic computed tomography (CT) performed within 1-4 months after the procedure. A p<0.05 was considered significant.

RESULTS

On a target lesion basis, the objective response (TE3/4) rate was 63.3% (31 of 49). On univariate analysis, larger size (≥2 cm) was a predictor of an objective response (p=0.029). The tumour location of the medial (segment 4) or caudate (segment 1) lobe also indicated a poor therapeutic effect (TE1/2), but not at the level of significance (p=0.051). Multivariate analysis identified tumour size (odds ratio, 8.60; 95% confidence interval, 1.87-62.8) and tumour location (odds ratio, 12.2; 95% confidence interval, 2.12-129.8) as significant factors associated with a therapeutic effect. On a patient basis, 10 of 25 (40%) patients showed complete response/partial response. There were no significant differences between complete response/partial response and stable disease/progressive disease regarding age, gender, tumour markers, history of previous treatment, Child-Pugh class, T-stage, or Barcelona Clinic Liver Cancer Staging.

CONCLUSION

A short-term therapeutic effect was associated with tumour size and location on a target lesion basis.

Fatty change in moderately and poorly differentiated hepatocellular carcinoma on MRI: a possible mechanism related to decreased arterial flow

AIM

To clarify the frequency of fatty change in moderately and poorly differentiated hepatocellular carcinomas (mHCCs and pHCCs) and its relationship to arterial blood flow.

MATERIALS AND METHODS

One hundred and thirty-six surgically resected HCC lesions were studied. All patients had undergone dynamic magnetic resonance imaging (MRI) with chemical-shift-encoded water-fat imaging (CSI). The presence of fat was identified by a signal drop-off on CSI and confirmed at pathology. Lesions were classified into four groups in the arterial phase; G1, hypointense; G2, isointense; G3, slightly and heterogeneously hyperintense; G4, markedly and homogeneously hyperintense. The number of cumulative arteries (CAs) in the tumours in the pathology examination were counted.

RESULTS

A fat component was observed significantly more frequently in the pHCCs (13/21; 61.9%) compared to the mHCCs (32/101; 31.7%; p=0.013). The numbers of lesions in each group were as follows: (G1, G2, G3, G4) = (18, 9, 23, 4) in the HCCs with fat; (1, 6, 24, 51) in the HCCs without fat (p<0.001); (5, 5, 18, 4) in the mHCCs with fat; (0, 3, 19, 47) in the mHCCs without fat (p<0.001); (11, 0, 2, 0) in the pHCCs with fat; (0, 2, 3, 3) in the pHCCs without fat (p=0.001). The number of CAs in the fat-containing HCCs (5.5±2.9) was significantly lower than that in the HCCs without fat (10.8±5.3; p<0.001).

CONCLUSION

A fat component was more commonly observed in the pHCCs than in the mHCCs. The present results showed a possible mechanism of fatty change in mHCCs and pHCCs in relation to decreased arterial blood supply.

Abnormal neutrophil scattergram obtained using Pentra MS CRP in the patients with myelodysplastic syndrome showing dysgranulopoiesis

INTRODUCTION

Pentra MS CRP is an automated hematology analyzer capable of cytochemistry using Chlorazol black E, a lipid-staining agent, for white blood cell (WBC) differentials. Pentra MS CRP displays a WBC scattergram according to the cell volume obtained using flow impedance and light absorbance reflecting the Chlorazol black E (CBE)-positive lipid content.

METHOD

Neutrophil scattergrams obtained using Pentra MS CRP were compared between 5 patients with myelodysplastic syndrome (MDS) and normal controls. Sudan black B (SBB)-staining patterns of peripheral blood neutrophils were subdivided into four types (types I, II, III, and VI) based on their staining intensity and scored by counting 200 cells. Such SBB scores were also compared between the two groups.

RESULTS

Neutrophil scattergrams deviated downward in the MDS group, suggesting the decreased CBE positivity that seemed reflect the reduction of the lipid content in dysplastic neutrophils. SBB scores determined in this study were also decreased in the MDS group when compared with those in normal controls.

CONCLUSION

Pentra MS CRP might rapidly generate useful information on dysplastic neutrophils in patients with MDS based on its cytochemistry for WBC differentials during routine laboratory hematology.

Theoretical study of core-loss electron energy-loss spectroscopy at graphene nanoribbon edges

A systematic study of simulated atomic-resolution electronic energy-loss spectroscopy (EELS) for different graphene nanoribbons (GNRs) is presented. The results of ab initio studies of carbon [Formula: see text] core-loss EELS on GNRs with different ribbon edge structures and different hydrogen terminations show that theoretical core-loss EELS can distinguish key structural features at the atomic scale. In addition, the combination of polarized core-loss EELS with symmetry resolved electronic partial density of states calculations can be used to identify the origins of all the primary features in the spectra. For example, the nature of the GNR edge structure (armchair, zigzag, etc) can be identified, along with the degree of hydrogenation. Hence it is possible to use the combination of ab initio calculations with high resolution, high energy transmission core-loss EELS experiments to determine the local atomic arrangement and chemical bonding states (i.e. a structural fingerprint) in GNRs, which is essential for future practical applications of graphene.

Anti-tumour effect of metformin in canine mammary gland tumour cells

Metformin is an oral hypoglycaemic drug used in type 2 diabetes. Its pharmacological activity reportedly involves mitochondrial respiratory complex I, and mitochondrial respiratory complex inhibitors have a strong inhibitory effect on the growth of metastatic canine mammary gland tumour (CMGT) cell lines. It is hypothesised that metformin has selective anti-tumour effects on metastatic CMGT cells. The aim of this study was to investigate the in vitro effect of metformin on cell growth, production of ATP and reactive oxygen species (ROS), and the AMP-activated protein kinase (AMPK) mammalian target of rapamycin (mTOR) pathway in two CMGT clonal cell lines with different metastatic potential. In addition, transcriptome analysis was used to determine cellular processes disrupted by metformin and in vivo anti-tumour effects were examined in a mouse xenograft model. Metformin inhibited CMGT cell growth in vitro, with the metastatic clone (CHMp-5b) displaying greater sensitivity. ATP depletion and ROS elevation were observed to a similar extent in the metastatic and non-metastatic (CHMp-13a) cell lines after metformin exposure. However, subsequent AMPK activation and mTOR pathway inhibition were prominent only in metformin-insensitive non-metastatic cells. Microarray analysis revealed inhibition of cell cycle progression by metformin treatment in CHMp-5b cells, which was further confirmed by Western blotting and cell cycle analysis. Additionally, metformin significantly suppressed tumour growth in xenografted metastatic CMGT cells. In conclusion, metformin exhibited an anti-tumour effect in metastatic CMGT cells through AMPK-independent cell cycle arrest. Its mechanism of action differed in the non-metastatic clone, where AMPK activation and mTOR inhibition were observed.

Effect of heat stress soon after muscle injury on the expression of MyoD and myogenin during regeneration process

Heat stress could promote skeletal muscle regeneration. But, in the regeneration process, effects of heat stress on myogenic cells and the regulating factors is unknown. Therefore, Influences of heat stress soon after injury on distribution of the myogenic cells and chronological changes in expression of MyoD and myogenin were examined. The first peak of MyoD expression was temporally correlated with the time when proliferating satellite cells began to appear, and the rapid decline of the MyoD expression from the first peak, with the appearance time of myoblasts, respectively in both the non-Heat and Heat groups. The first peak of myogenin expression was temporally correlated with the time when multinuclear cells began to form in the both groups. Due to the heat stress, proliferation and differentiation of myogenic cells and chronological changes in these factors were accelerated one day earlier than in the non-Heat group. As MyoD and myogenin are regulating factor of proliferation and differentiation, heat stress soon after the muscle injury could accelerate the proliferation and differentiation of myogenic cells and the expression of their regulating factors MyoD and myogenin.

Basic evaluation of Pentra MS CRP, a new automated hematology analyzer for rapid 5-part WBC differential and CRP using a small volume of whole blood

INTRODUCTION

Pentra MS CRP is a new automated hematology analyzer that can rapidly and reliably provide 5-part differential of leukocytes (5-Diff) and C-reactive protein (CRP) within approximately 3.5 min using a small volume of whole blood (35 μL).

METHODS

We evaluated the basic performance of Pentra MS CRP and correlations with Sysmex XN-3000, manual microscopic count, and Hitachi LABOSPECT.

RESULTS

Pentra MS CRP demonstrated good repeatability and linearity without any significant carryover for all parameters examined (WBC, RBC, HGB, Hct, PLT, 5-Diff, and CRP). Complete blood cell count (CBC) data examined by Pentra MS CRP correlated well with those evaluated by Sysmex XN-3000 (R ≥ 0.9880). Absolute number of NEU, LYM, and EOS also showed the good correlation (R ≥ 0.9866) between the two analyzers. The correlation with the manual microscopic count was within acceptable criteria. Furthermore, when CRP was examined in hemolyzed whole blood by Pentra MS CRP and converted to plasma concentrations according to Hct, it correlated well (R = 0.9964) with serum CRP examined by Hitachi LABOSPECT.

CONCLUSION

Pentra MS CRP is a convenient and reliable analyzer especially in the emergency unit of hospitals in which the prompt and simultaneous measurement of CBC including 5-Diff and CRP is often necessary.

Signal-transducing adaptor protein-2 regulates macrophage migration into inflammatory sites during dextran sodium sulfate induced colitis

Signal-transducing adaptor protein-2 (STAP-2) was cloned as a c-fms/M-CSF receptor interacting protein. STAP-2 is an adaptor protein carrying pleckstrin homology and Src homology 2 like domains, as well as a YXXQ motif. STAP-2 has been indicated to have an ability to bind and modulate a variety of signaling and transcriptional molecules. Especially, our previous in vitro studies showed that STAP-2 is crucial for immune and/or inflammatory responses. Here, we have investigated the role of STAP-2 in intestinal inflammation in vivo. The disruption of STAP-2 attenuates dextran sodium sulfate induced colitis via inhibition of macrophage recruitment. To study whether hematopoietic or epithelial cell derived STAP-2 is required for this phenomenon, we generated BM chimeric mice. STAP-2-deficient macrophages impair the ability of CXCL12-induced migration. Intriguingly, STAP-2 also regulates production of proinflammatory chemokines and cytokines such as CXCL1 and TNF-α from intestinal epithelial cells. Therefore, STAP-2 has a potential to regulate plural molecular events during pathological inflammatory responses. Furthermore, our findings not only indicate that STAP-2 is important in regulating intestinal inflammation, but also provide new insights toward the development of novel therapeutic approaches.

A prospective, randomized, double-blind, controlled trial on the efficacy of carbon dioxide insufflation in gastric endoscopic submucosal dissection

BACKGROUND AND STUDY AIMS

Carbon dioxide (CO2) insufflation is expected to be safe and effective in endoscopic submucosal dissection (ESD) as well as in other endoscopic procedures. The present study aimed to clarify the usefulness and safety of CO2 insufflation in gastric ESD.

PATIENTS AND METHODS

A total of 102 consecutive patients were randomly assigned to CO2 insufflation (CO2 group, n = 54) or air insufflation (Air group, n = 48). Abdominal pain and distension were chronologically recorded on a 100-mm visual analog scale (VAS). The volume of residual gas in the digestive tract was measured by computed tomography performed immediately after ESD.

RESULTS

Abdominal pain on a 100-mm VAS in the CO2 vs. Air group was 4 vs. 3 immediately after ESD, 4 vs. 4 one hour after the procedure, 3 vs. 3 three hours after the procedure, and 1 vs. 4 the next morning, showing no difference between the groups. In addition, there was no difference in abdominal distension on the 100-mm VAS over the time course of the study. The volume of residual gas in the digestive tract in the CO2 group was significantly smaller than that in the Air group (643 mL vs. 1037 mL, P < 0.001). The dose of sedative drugs did not differ between the groups. Neither the incidences of complications nor clinical courses differed between the groups.

CONCLUSIONS

Compared with air insufflation, CO2 insufflation during gastric ESD significantly reduced the volume of residual gas in the digestive tract but not the VAS score of abdominal pain and distension.

Estimation of regional cerebral blood flow using N-isopropyl-p-123I iodoamphetamine acquisition data from the lungs and brain

Aim: Previously, we devised a method for estimating 123I labeled N-isopropyl-p-iodo- amphetamine (123I IMP) arterial blood activity at 10 minutes after intravenous injection of 123I IMP (Ca10) without any blood sampling using 123I IMP autoradiography (ARG) acquisition data, and verified its usefulness for quantification of regional cerebral blood flow (rCBF). In this study, we attempted to develop an improved noninvasive method for estimating rCBF. Patients, methods: 123I IMP studies with 23 patients and 15O-H2O positron emission tomography (PET) ARG studies with 20 patients were evaluated. Multiple regression analysis was used to estimate an integral of the arterial blood counts during the time after injection of 123I (JCa) using parameters from the time series of the lung counts and brain counts as the explanatory variables and the fraction [brain single-photon emission computed tomography (SPECT) average count / the mean of rCBFs (mean CBF) measured by 15O-H2O PET ARG method] as the objective variable. Results: The regression equation was as follows: Estimated JCa = (7.09x10-3 · Cb12) - (1.57x10-4 · CbpreSPECT) + (9.48x10-5 · CbpostSPECT) + (1.35x10-4· L15) - (6.95x10-4· L33) + (7.61x10-4· L81) - (0.417), where Cb12: brain count at 12 minutes, Cbpre-SPECT: brain count before SPECT, Cbpost-SPECT: brain count after SPECT, L15, L33, and L81: lung count at 15, 33, and 81 seconds, respectively. The mean CBF values (ml/min/100g) calculated using the estimated JCa values more closely correlated with those measured by 15O-H2O PET ARG method (r = 0.833, p < 0.01) than those obtained by our previous method (r = 0.590, p < 0.01). Conclusion: The rCBFs obtained by this method approximated more accurately to the values measured by 15O-H2O PET ARG method than those obtained by our previous method.

Preventive effect of nucleoprotein on hindlimb unloading-induced capillary regression in rat soleus muscle

We investigated the preventive effects of nucleoprotein on capillary regression and mitochondrial dysfunction induced by unloading in the soleus muscle of rats. Nucleoprotein is a supplement made from soft roe of salmon, and its major components are nucleotides and protamine. Adult male Sprague-Dawley rats were divided randomly into control, hindlimb unloading (HU), and hindlimb unloading plus nucleoprotein administration (HU+ NP) groups. Hindlimb unloading was carried out for 2 weeks in the rats belonging to the HU and the HU+ NP groups. The rats of the HU+ NP group were administered nucleoprotein (500 mg/kg) using a feeding needle twice a day for 2 weeks. Hindlimb unloading resulted in capillary regression, decreased succinate dehydrogenase activity of the muscle fiber, and decreased PGC-1α expression in the soleus muscle. These effects were prevented by administration of nucleoprotein. Nucleoprotein appears to prevent capillary regression and mitochondrial dysfunction caused by unloading of the skeletal muscle. Therefore, nucleoprotein supplementation may be an effective therapy for maintaining capillary network and mitochondrial metabolism of the muscle fiber during an unloading period.

Protective effects of astaxanthin on capillary regression in atrophied soleus muscle of rats

AIM

The capillary regression in skeletal muscles associated with a chronic decrease in activity is related to a dysfunction of endocapillary cells induced by over-expression of oxidative stress. We hypothesized that treatment with astaxanthin, an antioxidant, would attenuate the oxidative stress induced by decreased skeletal muscle use, and that this attenuation would prevent the associated capillary regression. The purpose of the present study was to investigate the antioxidant and preventive effects of astaxanthin on capillary regression in the soleus muscle during hindlimb unloading.

METHODS

Twenty-four adult male Wistar rats were assigned randomly either to a control, control plus astaxanthin treatment, hindlimb unloaded or hindlimb unloaded plus astaxanthin treatment group for 7 days.

RESULTS

Hindlimb unloading resulted in a decrease in mean soleus absolute weight, capillary number, volume and luminal diameter. The accumulation of reactive oxygen species and the over-expression of superoxide dismutase (SOD-1), a decrease in the levels of vascular endothelial growth factor (VEGF) and its receptors, an inhibition of the angiopoietin pathway and an increase of thrombospondin-1 (TSP-1), as an anti-angiogenic factor were showed. Administration of astaxanthin attenuated the changes in SOD-1 and VEGF, up-regulated the angiogenic factors and reduced the capillary regression in the soleus of hindlimb unloaded rats. In addition, the VEGF-to-TSP1 ratio was higher in the astaxanthin treated groups than in the control and HU groups.

CONCLUSION

These results suggest that astaxanthin may be an effective treatment to counter the detrimental effects of a chronic decrease in skeletal muscle use on the capillary network and associated angiogenic pathways.

Switching dynamics and linear response spectra of a driven one-dimensional nonlinear lattice containing an intrinsic localized mode

An intrinsic localized mode (ILM) represents a localized vibrational excitation in a nonlinear lattice. Such a mode will stay in resonance as the driver frequency is changed adiabatically until a bifurcation point is reached, at which point the ILM switches and disappears. The dynamics behind switching in such a many body system is examined here through experimental measurements and numerical simulations. Linear response spectra of a driven micromechanical array containing an ILM were measured in the frequency region between two fundamentally different kinds of bifurcation points that separate the large amplitude ILM state from the two low amplitude vibrational states. Just as a natural frequency can be associated with a driven harmonic oscillator, a similar natural frequency has been found for a driven ILM via the beat frequency between it and a weak, tunable probe. This finding has been confirmed using numerical simulations. The behavior of this nonlinear natural frequency plays important but different roles as the two bifurcation points are approached. At the upper transition its frequency coalesces with the driver and the resulting bifurcation is very similar to the saddle-node bifurcation of a single driven Duffing oscillator, which is treated in an Appendix. The lower transition occurs when the four-wave mixing partner of the natural frequency of the ILM intersects the topmost extended band mode of the same symmetry. The properties of linear local modes associated with the driven ILM are also identified experimentally for the first time and numerically but play no role in these transitions.

Downregulation of AKT reverses platinum resistance of human ovarian cancers in vitro

Platinum resistance is the most crucial problem for treatment of ovarian cancer. Increasing evidence points towards AKT overexpression as a mechanistic reason for this clinical condition. The present study evaluates the effect of overexpression and downregulation of AKT on the sensitivity to cisplatin in a platinum-resistant human ovarian cancer cell line and the corresponding platinum-sensitive parental cell line. A2780 and A2780cis ovarian cancer cell lines were stably transfected with an AKT-sense and AKT-antisense plasmid. Successful transfection was evaluated by western blot analysis. Cytotoxic effects of cisplatin were evaluated by metabolic (MTT) and clonogenicity assays as well as by FACS analysis. AKT overexpression (confirmed by western blotting) converted platinum-sensitive A2780 into platinum-resistant cells as shown by MTT assay. Importantly, platinum resistance of A2780cis cells could be reversed by downregulation of AKT, as demonstrated by MTT and clonogenicity assays and FACS analysis. Our data provide strong evidence that cisplatin resistance in ovarian cancer is mediated by AKT overexpression and can be overcome by AKT downregulation, thus, providing a rationale for clinical phase II/III studies combining AKT inhibitors with cisplatin.

A pilot study to assess mediastinal emphysema after esophageal endoscopic submucosal dissection with carbon dioxide insufflation

BACKGROUND AND AIMS

Mediastinal emphysema sometimes develops following esophageal endoscopic submucosal dissection (ESD) without perforation because the esophagus has no serosa. Carbon dioxide (CO2) insufflation during esophageal ESD may reduce the incidence of mediastinal emphysema. The aim of the present study was to compare the incidence and severity of post-ESD mediastinal emphysema in patients receiving CO2 insufflation vs. standard air insufflation during esophageal ESD.

PATIENTS AND METHODS

A total of 27 patients who had undergone esophageal ESD with insufflation of CO2 between July 2009 and March 2010 were enrolled in this study (CO2 group). Another 105 patients who had undergone esophageal ESD with air insufflation between March 2004 and May 2009 were included as historical controls (air group). Multi-detector row computed tomography (MDCT) was carried out immediately after ESD. A conventional chest radiograph was taken the next day. Mediastinal emphysema findings on MDCT and radiography were compared between the groups.

RESULTS

Mediastinal emphysema detected by chest radiography was 0 % in the CO2 group vs. 6.6 % in the air group (n.s.). Mediastinal emphysema on MDCT was significantly less frequent in the CO2 group compared with the air group (30 % vs. 63 %; P = 0.002). The severity of mediastinal emphysema also tended to be lower in the CO2 group.

CONCLUSIONS

Whereas mediastinal emphysema detected by radiography is not so common, MDCT immediately after ESD revealed a certain prevalence of post-ESD mediastinal emphysema. Insufflation of CO2 rather than air during esophageal ESD significantly reduced postprocedural mediastinal emphysema. CO2 can be considered as insufflating gas for esophageal ESD.

Can health systems be enhanced for optimal health services through disease-specific programs? Results of field studies in Viet Nam and Cambodia

Developing better health systems is the key to delivering optimal health services, although more evidence of effective strategies to do so is needed. Field surveys were conducted in Viet Nam and Cambodia to identify best practices in addressing health system bottlenecks to scale up disease control programs. The two countries were compared over time using a framework for analysis developed by the authors. In Viet Nam, a health system was in place for decades at the central to municipal levels, although it was fragile until the 1990s, when the government started taking measures. In Cambodia, the previous health system had been destroyed during previous internal conflict. In the post-conflict period, the health system was rebuilt with support for programs followed by centralization of health services. In different settings, different measures were taken to deal with similar bottlenecks. In Cambodia, vertical programs were dominant, so the government sought to centralize drug management to deal with shortages of essential drugs, while Viet Nam sought to mobilize resources to ensure drug distribution at all levels. This study shows there is no single successful approach to health systems, and a systemic approach needs to be taken because elimination of one bottleneck may reveal another. Efforts to enhance disease-specific programs may not always contribute to overall enhancement of the health system, and the best possible approach may not be the same in different countries. Further study is needed to explore common issues and principles for effective strategies to enhance health systems in different contexts.