Synergistic anti-tumor effects of lenalidomide and gefitinib by upregulating ADRB2 and inactivating the mTOR/PI3K/AKT signaling pathway in lung adenocarcinoma

Gefitinib is commonly used to be the first-line therapy for advanced non-small cell lung cancer (NSCLC). Therapeutic effect of gefitinib is reduced due to acquired resistance, and combined treatment is recommended. In this research, we planned to explore the impacts of combined treatment of lenalidomide and gefitinib on gefitinib-sensitive or -resistant NSCLC cells. The co-treatment results demonstrated that enhanced antitumor impact on NSCLC cell growth, migration, invasion, cell cycle process and apoptosis. The tumor-bearing mouse models were established using PC9/GR cells. In vivo assays also showed that lenalidomide and gefitinib synergistically inhibited mouse tumor growth along increased the survival of mice. ADRB2 was identified as a lowly expressed gene in PC9/GR cells and LUAD tumor tissues. LUAD patients with high ADRB2 expression were indicated with favorable survival outcomes. Moreover, ADRB2 was upregulated in lenalidomide and/or gefitinib-treated PC9/GR cells. ADRB2 deficiency partially offsets the suppressive impacts of lenalidomide and gefitinib co-treatment on the viability and proliferation of PC9/GR cells. Additionally, lenalidomide and gefitinib cotreatment significantly inactivated the mTOR/PI3K/AKT signaling pathway compared with each treatment alone. Rescue assays were performed to explore whether lenalidomide and gefitinib synergistically inhibited the growth of PC9/GR cells via the PI3K/AKT pathway. PI3K activator SC79 significantly restored reduced cell proliferation, migration and invasion along with elevated cell cycle arrest and apoptosis caused by lenalidomide and gefitinib cotreatment. In conclusion, lenalidomide and gefitinib synergistically suppressed LUAD progression and attenuated gefitinib resistance by upregulating ADRB2 and inactivating the mTOR/PI3K/AKT signaling pathway in lung adenocarcinoma.

The role of TMEM26 in disrupting tight junctions and activating NF-κB signaling to promote epithelial-mesenchymal transition in esophageal squamous cell carcinoma

OBJECTIVES

Metastasis is one of the biggest challenges in the management of Esophageal Squamous Cell Carcinoma (ESCC), of which molecular mechanisms remain elusive. The present study aimed to explore the roles and underlying mechanisms of Transmembrane protein 26 (TMEM26) in ESCC.

METHOD

TMEM26 expressions in tumorous and adjacent tissues from patients with ESCC and in normal esophageal epithelial and ESCC cell lines were detected by immunostaining and western blotting, respectively. The Epithelial-Mesenchymal Transition (EMT), a critical process during metastasis, was investigated by wound healing and Transwell assays, and EMT-related proteins were examined after the TMEM26 alteration in ESCC cell lines. NF-κB signaling activation and Tight Junction (TJ) protein expression were analyzed by western blotting and immunofluorescence, respectively. In vivo verification was performed on the liver metastatic murine model.

RESULTS

Compared with non-cancerous esophageal tissues and cells, the TMEM26 expression level was higher in ESCC samples and cell lines, where the plasma membrane localization of TMEM26 was observed. The EMT-related processes of ESCC cells were suppressed by RNAi depletion of TMEM26 but aggravated by TMEM26 overexpression. Mechanistically, TMEM26 promoted NF-κB signaling to accelerate EMT in ESCC cells. The plasma membrane presentation and assembly of TJ proteins were impaired by TMEM26.

CONCLUSION

Overall, TMEM26 acts as a critical determinant for EMT in ESCC cells by disrupting TJ formation and promoting NF-κB signaling, which may be a potential therapeutic target for treating metastatic ESCC.

Development and validation of a multiphase CT radiomics nomogram for the preoperative prediction of lymphovascular invasion in patients with gastric cancer

AIM

To develop a nomogram to predict lymphovascular invasion (LVI) in gastric cancer by integrating multiphase computed tomography (CT) radiomics and clinical risk factors.

MATERIALS AND METHODS

One hundred and seventy-two gastric cancer patients (121 training and 51 validation) with preoperative contrast-enhanced CT images and clinicopathological data were collected retrospectively. The clinical risk factors were selected by univariate and multivariate regression analysis. Radiomic features were extracted and selected from the arterial phase (AP), venous phase (VP), and delayed phase (DP) CT images of each patient. Clinical risk factors, radiomic features, and integration of both were used to develop the clinical model, radiomic models, and nomogram, respectively.

RESULTS

Radiomic features from AP (n=6), VP (n=6), DP (n=7) CT images and three selected clinical risk factors were used for model development. The nomogram showed better performance than the AP, VP, DP, and clinical models in the training and validation datasets, providing areas under the curves (AUCs) of 0.890 (95% CI: 0.820-0.940) and 0.885 (95% CI:0.765-0.957), respectively. All models indicated good calibration, and decision curve analysis proved that the net benefit of the nomogram was superior to that of the clinical and radiomic models throughout the vast majority of the threshold probabilities.

CONCLUSIONS

The nomogram integrating multiphase CT radiomics and clinical risk factors showed favourable performance in predicting LVI of gastric cancer, which may benefit clinical practice.

Peripheral Blood Markers Predictive of Progression-Free Survival in Advanced Esophageal Squamous Cell Carcinoma Patients Treated With PD-1 Inhibitors Plus Chemotherapy as First-Line Therapy

Aim: To determine the prognostic value of peripheral blood markers in advanced esophageal squamous cell carcinoma (ESCC) patients receiving programmed cell death protein 1 inhibitors plus chemotherapy as first-line therapy. Methods: A retrospective analysis of 54 patients with advanced ESCC was performed to assess 12 blood markers involving inflammation, nutrition, and tumor burden. Analysis of variance or Kruskal-Wallis tests were used to explore the difference in markers among different response to therapy. Survival curves were constructed using the Kaplan-Meier method. Multivariate Cox models were applied to identify independent predictors of outcome. Results: Patients who achieved response had significantly higher prealbumin, increased BMI, and lower hs-CRP levels at baseline compared with those who experienced disease progression. In the univariate analysis, ALI > 23.55, PNI > 45.175, NLR ≤ 5, and hs-CRP ≤ 6.7 mg/L were significantly associated with a better progression-free survival. Cox regression analysis revealed that ALI >23.55 (P = 0.037) and hs-CRP ≤6.7 mg/L (P = 0.043) were independently associated with superior PFS. Increased tumor abnormal protein (TAP) levels post two cycles was significantly associated with a worse prognosis (P = 0.004). Conclusions: A baseline signature of low ALI and high hs-CRP as well as an early increase in TAP in ESCC appear to be predictive of inferior PFS.

Effect of palliative microwave ablation on metastatic osseous pain: a single-center retrospective study

BACKGROUND

Bone is among the most common metastasis sites in patients with advanced cancer. Approximately two-thirds of bone metastasis results in pain, the majority of which is moderate to unbearable pain, which seriously affects the quality of life of patients. With the development of ablation techniques, microwave ablation (MWA) has great potential to eliminate the pain caused by bone metastasis. This study aimed to evaluate the efficacy and safety of image-guided (computed tomography-guided) percutaneous MWA for metastatic osseous pain.

METHODS

This is a retrospective study involving 18 patients with cancer-related pain caused by osseous or soft tissue metastasis in the First Affiliated Hospital of Soochow University from June 2015 to October 2020. All patients (14 men and 4 women; mean age 60.2 years) underwent image-guided percutaneous palliative MWA. A paired-sample t-test was used to compare the changes in Numeric Rating Scale (NRS) score and dosage of morphine preoperatively and postoperatively (at 24 h, 3 days, and 14 days after MWA). In addition, we assessed the level of pain relief according to the patients' subjective feelings.

RESULTS

The paired-samples t-test showed that the NRS score (6.83±0.92 vs. 1.67±0.97, P<0.05) and dosage of morphine (85.56±17.23 vs. 32.78±4.61, P<0.05) were significantly decreased at 3 days after MWA. At 14 days after MWA, the NRS score (6.83±0.92 vs. 0.94±0.87, P<0.05) and dosage of morphine (85.56±17.23 vs. 10.56±8.73, P<0.05) were also markedly decreased. Moreover, according to the patients' subjective feeling, 88.89% patients had pain relief postoperatively, while the remaining patients had no progress.

CONCLUSIONS

Image-guided (Computed Tomography-guided) percutaneous MWA can effectively relieve pain, thus improving the quality of life in patients with osseous metastasis. MWA is a feasible, safe, and effective treatment for pain caused by bone metastasis.

The expressions of miR-151a-5p and miR-23b in lung cancer tissues and their effects on the biological functions of lung cancer A549 cells

OBJECTIVE

To investigate the expressions of miR-151a-5p and miR-23b in lung cancer tissues and their effects on the biological functions of lung cancer A549 cells.

PATIENTS AND METHODS

Samples of lung cancer tissue (55 cases) and pericarcinomatous tissue (55 cases) were collected in thoracic surgery in our hospital from May 2017 to November 2018. The expression levels of miR-151a-5p and miR-23b in lung cancer tissues and pericarcinomatous tissues were detected by RT-PCR. Lung cancer cells A549 were transfected. Before transfection, the cells were divided into a negative control group (NC group, transfected with miRNA NC), a group transfected with miR-151a-5p inhibitor and a group transfected with miR-23b inhibitor. MTS Cell Proliferation Colorimetric Assay Kit (CCK8) was used to detect cell proliferation and draw the growth curve. Transwell chamber was used to detect the invasion ability in vitro, and BD flow cytometry was used to detect apoptosis in each group.

RESULTS

The expression levels of miR-151a-5p and miR-23b in lung cancer tissues were significantly higher than those in pericarcinomatous tissues (p<0.001). After 48 h to 72 h, the cell growth of both the miR-151a-5p inhibitor group and the miR-23b inhibitor group was significantly lower than that of the NC group (p<0.001). The numbers of invasion of miR-151a-5p inhibitor group and miR-23b inhibitor group were significantly lower than that of NC group (p<0.00). The apoptosis rates of miR-151a-5p inhibitor group and miR-23b inhibitor group were significantly higher than that of NC group (p<0.001).

CONCLUSIONS

Both miR-151a-5p and miR-23b are highly expressed in lung cancer, and the inhibition of miR-151a-5p and miR-23b can restrain the proliferation, invasion and migration of lung cancer A549 cells, thereby promoting the apoptosis of lung cancer A549 cells.

Modeled changes to the Great Plains low-level jet under a realistic irrigation application

Low-level jets (LLJs) are relatively fast-moving streams of air that form in the lower troposphere and are a common phenomenon across the Great Plains (GP) of the United States. LLJs play an important role in moisture transport and the development of nocturnal convection in the spring and summer. Alterations to surface moisture and energy fluxes can influence the planetary boundary layer (PBL) development and thus LLJs. One important anthropogenic process that has been shown to affect the surface energy budget is irrigation. In this study, we investigate the effects of irrigation on LLJ development across the GP by incorporating a dynamic and realistic irrigation scheme into the Weather Research and Forecasting (WRF) model. WRF simulations were conducted with and without the irrigation scheme for the exceptionally dry summer of 2012 over the GP. The results show irrigation-introduced changes to LLJ features both over and downstream of the most heavily irrigated regions in the GP. There were statistically significant increases to LLJ speeds in the simulation with the irrigation parameterization. Decreases to the mean jet core height on the order of 50 m during the overnight hours were also simulated when irrigation was on. The overall frequency of jet occurrences increased over the irrigated regions by 5-10%; however, these differences were not statistically significant. These changes were weaker than those reported in earlier studies based on simple representations of irrigation that unrealistically saturate the soil columns over large areas over a long period of time, which highlights the importance and necessity to represent human activity more accurately in modeling studies.

Tailoring optical pulling force on gain coated nanoparticles with nonlocal effective medium theory

We study the optical scattering force on the coated nanoparticles with gain core and nonlocal plasmonic shell in the long-wavelength limit, and demonstrate negative optical force acting on the nanoparticles near the symmetric and/or antisymmetric surface plasmon resonances. To understand the optical force behavior, we propose nonlocal effective medium theory to derive the equivalent permittivity for the coated nanoparticles with nonlocality. We show that the imaginary part of the equivalent permittivity is negative near the surface resonant wavelength, resulting in the negative optical force. The introduction of nonlocality may shift the resonant wavelength of the optical force, and strengthen the negative optical force. Two examples of Fano-like resonant scattering in such coated nanoparticles are considered, and Fano resonance-induced negative optical force is found too. Our findings could have some potential applications in plasmonics, nano-optical manipulation, and optical selection.

[Epidemiological investigation of hospitalized children with burn injury in a hospital of Qingdao]

Objective: To investigate epidemiological characteristics of hospitalized children with burn injury in the author's affiliation, so as to provide theoretical basis for developing prevention strategies of children with burn injury. Methods: Medical records of 384 and 596 hospitalized children with burn injury, aged 0 to 12-year-old, were collected respectively from January 2001 to December 2005 and January 2011 to December 2015. Percentage of children with burn injury to total hospitalized patients with burn injury in the same period of time, age, causes of injury, gender, injury month, residence, condition of first aid measures conforming to medical standard, time of admission post injury, burn degree, and operation condition of children with burn injury were analyzed. Data were processed with Mann-Whitney U test and Chi-square test. Results: From January 2001 to December 2005 and January 2011 to December 2015, percentages of children with burn injury to total hospitalized patients with burn injury in the same period of time were respectively 23.6% (384/1 626) and 25.4% (596/2 346) , with no statistically significant difference (χ(2)=1.653, P>0.05). Age of all children with burn injury was 1.0 (1.0, 2.0) year old from January 2011 to December 2015, obviously lower than that from January 2001 to December 2005[1.0 (1.0, 3.0) year old, Z=-3.257, P<0.01]. Ages of children with burn caused by hot liquid and electrical burn from January 2011 to December 2015 were obviously lower than those from January 2001 to December 2005 (with Z values respectively -4.248 and -2.040, P<0.05 or P<0.01). Compared with that from January 2001 to December 2005, age of children with burn caused by flame from January 2011 to December 2015 increased, with no statistically significant difference (Z=1.852, P>0.05). There was no statistically significant difference in gender of children with burn injury between the two periods of time (χ(2)=1.374, P>0.05). Burn injury of children in the two periods of time mainly occurred in Spring, and season of burn injury between the two periods of time was similar (χ(2)=1.177, P>0.05). There was statistically significant difference in residence of children with burn injury between the two periods of time (χ(2)=15.513, P<0.01). The number of children with burn injury of first aid measures conforming to medical standard and admission within 6 h post injury from January 2011 to December 2015 was obviously more than that from January 2001 to December 2005 (with χ(2) values respectively 7.434 and 43.961, P values below 0.01). Burn degrees of children with burn injury mainly were moderate in the two periods of time, and there was no statistically significant difference in burn degree and condition of operation between the two periods of time (with χ(2) values respectively 5.731 and 1.583, P values above 0.05). Conclusions: Burn of children is a social problem. We should make great efforts on popularization of prevention and treatment about burn of children, especially children with younger age in rural areas. We should publicize standard first aid measures of burn of children and advocate admission of burn of children within 6 h post burn injury for treatment.

Clinical effect of azithromycin as an adjunct to non-surgical treatment of chronic periodontitis: a meta-analysis of randomized controlled clinical trials

The results of recent published studies focusing on the effect of azithromycin as an adjunct to scaling and root planing (SRP) in the treatment of chronic periodontitis are inconsistent. We conducted a meta-analysis of randomized controlled clinical trials to examine the effect of azithromycin combined with SRP on periodontal clinical parameters as compared to SRP alone. An electronic search was carried out on Pubmed, Embase and the Cochrane Central Register of Controlled Trials from their earliest records through December 28, 2014 to identify studies that met pre-stated inclusion criteria. Reference lists of retrieved articles were also reviewed. Data were extracted independently by two authors. Either a fixed- or random-effects model was used to calculate the overall effect sizes of azithromycin on probing depth, attachment level (AL) and bleeding on probing (BOP). Heterogeneity was evaluated using the Q test and I(2) statistic. Publication bias was evaluated by Begg's test and Egger's test. A total of 14 trials were included in the meta-analysis. Compared with SRP alone, locally delivered azithromycin plus SRP statistically significantly reduced probing depth by 0.99 mm (95% CI 0.42-1.57) and increased AL by 1.12 mm (95% CI 0.31-1.92). In addition, systemically administered azithromycin plus SRP statistically significantly reduced probing depth by 0.21 mm (95% CI 0.12-0.29), BOP by 4.50% (95% CI 1.45-7.56) and increased AL by 0.23 mm (95% CI 0.07-0.39). Sensitivity analysis yielded similar results. No evidence of publication bias was observed. The additional benefit of systemic azithromycin was shown at the initially deep probing depth sites, but not at shallow or moderate sites. The overall effect sizes of systemic azithromycin showed a tendency to decrease with time, and meta-regression analysis suggested a negative relation between the length of follow-up and net change in probing depth (r = -0.05, p = 0.02). This meta-analysis provides further evidence that azithromycin used as an adjunct to SRP significantly improves the efficacy of non-surgical periodontal therapy on reducing probing depth, BOP and improving AL, particularly at the initially deep probing depth sites.

Non-invasive prenatal testing for fetal aneuploidies in the first trimester of pregnancy

OBJECTIVES

To evaluate the feasibility of non-invasive prenatal testing (NIPT) of maternal plasma samples collected from pregnant Chinese women in early gestation, between 8 + 0 and 12 + 6 weeks' gestation.

METHODS

In this pilot study, 212 women with high-risk pregnancies were recruited at a single Chinese Hospital. Fetal aneuploidies associated with chromosomes 21, 18, 13, X and Y were detected by massively parallel sequencing of maternal plasma DNA samples. Invasive prenatal diagnosis by either chorionic villus sampling or amniocentesis and then karyotyping was offered to all women to confirm both positive and negative NIPT results. Fetal DNA fraction was also determined in male pregnancies, by the relative percentage of Y-chromosome sequences. All confirmed NIPT-negative pregnancies were followed up to birth and neonates were clinically evaluated for any symptoms of chromosomal disease.

RESULTS

Autosomal aneuploidies trisomy 21 (n = 2), 18 (n = 1) and 13 (n = 1) were detected by NIPT and confirmed by amniocentesis and karyotyping. There were one false-positive 45,X sample and two false-negative samples associated with fetal karyotypes 47,XXY and 45,X[16]/47,XXX[14]. In the 100 male pregnancies, the median fetal DNA fraction was 8.54% and there was a trend towards an increasing fetal fraction from 8 + 0 to 12 + 6 weeks' gestation. The majority (95%) of pregnancies had a fetal DNA fraction > 4%, which is generally the limit for accurate aneuploidy detection by NIPT. Across this early gestational time period, there was a weak inverse relationship (R(2)  = 0.186) between fetal DNA fraction and maternal weight.

CONCLUSIONS

NIPT is highly reliable and accurate when applied to maternal DNA samples collected from pregnant women in the first trimester between 8 + 0 and 12 + 6 weeks.

Effects of high hemodynamics upon the morphology of the walls of the great saphenous vein and splenic vein

AIM

Studies have shown that the incidence and development of pathological changes in the walls of the great saphenous vein and splenic vein are closely related to high venous pressure. Such changes are referred to as "vascular adaptive remodeling responses under high venous pressure". The proposition of the concept of vascular remodeling contributes to our knowledge of pathological changes in the venous wall (dilation of the venous lumen and thickening of the venous wall). In the present study, we compared the histomorphology and cytomorphology of the walls of varicose great saphenous veins (GSVs) and diseased splenic veins (SVs) to investigate the remodeling of the venous wall under high hemodynamic pressure.

METHODS

We collected 34 samples of varicose great saphenous veins and diseased splenic veins. Thirty-four samples of normal great saphenous veins and splenic veins were also collected (control group). Samples were made into slices and observed under light microscopy and electron microscopy. The thickness of the tunica intima and tunica media as well as the inner diameter of the venous lumen were measured.

RESULTS

Under light microscopy, the walls of varicose veins stained with H&E were unevenly thickened, and those of diseased splenic veins were evenly thickened; mucoid degeneration of the tunica intima of varicose veins was not obvious by Masson staining (2/20 cases). The boundary between the tunica intima and tunica media was clearly defined. Uneven hyperplasia of muscular connective tissues was observed. For the diseased splenic-vein group, mucoid degeneration of the tunica intima was obvious (8/14 cases), with an unclearly defined boundary between the tunica intima and tunica extima. Uneven hyperplasia of muscular connective tissues was also observed. Differences in the thickness and inner diameter of the tunica intima and tunica media between the great saphenous vein and the splenic vein were significantly different. Under electron microscopy, mitochondrial degeneration in endothelial cells was observed in both groups. Increased numbers of rough endoplasmic reticula in the cytoplasm of smooth muscle cells, ribosomes and mitochondria and decreased numbers of myofilaments were also observed.

CONCLUSION

High hemodynamics affected the remodeling of varicose great saphenous veins and diseased splenic veins. The histomorphology of visceral veins showed more significant pathological changes than that of peripheral veins. Similar cytomorphological changes were observed in both groups.

Gene-gene interactions of IRF5, STAT4, IKZF1 and ETS1 in systemic lupus erythematosus

Interferon (IFN) activation signaling and T helper 17 (Th17)-cell/B-cell regulation play a critical role in the pathogenesis of systemic lupus erythematosus (SLE). Several studies have provided convincing evidence that polymorphisms in IRF5, STAT4, IKZF1 and ETS1 from these pathways may be involved in SLE by affecting gene expression or epistasis. We analyzed the genetic interaction in known SLE susceptibility loci from the four genes in northern Han Chinese. A total of 946 northern Han Chinese participated in this study (370 unrelated SLE patients and 576 healthy controls). Subjects underwent genotyping for the single-nucleotide polymorphisms (SNPs) rs2004640 in IRF5, rs7574865 in STAT4, rs4917014 in IKZF1 and rs1128334 in ETS1 by use of a TaqMan SNP genotyping assay and direct sequencing. Gene-gene interaction analysis involved direct counting, multifactor dimensionality reduction (MDR) and linear regression analysis. SLE patients and controls differed in allele frequencies of rs7574865, rs1128334 (P < 0.001) and rs4917014 (P < 0.01). Direct counting revealed that the frequency of risk homozygote combinations was higher for SLE patients than controls (P < 0.01). Furthermore, 2-, 3- and 4-way gene-gene epistasis in SLE was confirmed by parametric methods and MDR analysis. Gene expression analysis partially supported the findings. Our study confirmed the association of the IFN pathway or Th17/B-cells and the pathogenesis of SLE, and gene-gene interaction in this pathway may increase the risk of SLE.

Envelope surface ultrastructure and specific gravity of artificially fertilized Pacific cod Gadus macrocephalus eggs

The envelope surface ultrastructure and specific gravity of artificially fertilized eggs of the Pacific cod Gadus macrocephalus were examined. The unfertilized, demersal and slightly adhesive eggs of G. macrocephalus were almost spherical and had no oil globules. Wrinkled envelope surface with elaborated hexagonal reticulated patterns and type I micropyle were observed under a scanning electron microscope. The adhesiveness of the eggs was lost at the blastodermal-cap stage after fertilization. The micropylar canal was sealed by secretion of the perivitelline fluid, and the entire surface became rough. Numerous bacilli were deposited at the micropyle and the outer envelope surface at the late germ-ring stage and at the embryo five-eighths around the yolk stage. The micropyle was completely deformed at the embryo seven-eighths around the yolk stage. The specific gravity of the fertilized G. macrocephalus eggs ranged from c. 1·0316 to 1·0454. These values, however, sharply decreased towards the end stages of egg development to produce pelagic larvae. The ultrastructural changes in the micropyle and envelope surface of the G. macrocephalus eggs protected the embryo from microorganism infections and mechanical stress during the long incubation period. The adhesiveness and specific gravity of the eggs influenced their dispersion potential.

Temperature-mediated survival, development and hatching variation of Pacific cod Gadus macrocephalus eggs

Laboratory-validated data on the survival, development and hatching responses of fertilized Pacific cod Gadus macrocephalus eggs from the northern Japan stock were determined through an incubation experiment. The optimum temperature for survival until hatching ranged from 4 to 8°C. No significant difference in development rates was found between the populations from Mutsu Bay, Japan, and western Canadian coastal waters even though the samples may belong to different G. macrocephalus stocks. Gadus macrocephalus larvae hatched asynchronously from egg batches despite incubation under the same environment during their development. Both incubation temperature and temperature-mediated hatch rank affect size and yolk reserve. These data suggest that variations in water temperatures within an ecological range markedly influence the development rates, survival and hatching of the eggs, as well as the stage at hatch larvae of G. macrocephalus. Asynchronous hatching and the production of offspring with variable sizes and yolk reserves are considered evolutionary bet-hedging strategies that enable the species to maximize their likelihood of survival in an environment with variable temperatures.

Electrolytic partitioning of uranium and plutonium based on a new type of electrolytic mixer-settler

The design of a new type of electroreduction mixer-settler for the partitioning of uranium and plutonium during the Purex process, which is featured with E-shaped cathodes and U-shaped anodes in settling chamber, is described and the operational results achieved using this equipment are presented. The results show that this new type of mixer-settler has excellent separation performances. The flow rate of organic feed solution is 3 mL/min and the flow ratio of feed solution (1BF) to aqueous back extraction stream (1BX) and to organic wash stream (1BS) is 4/1/1. For an organic feed of 84 g/L uranium and 1.40 ⁓ 2.64 g/L plutonium, both the separation factor of plutonium from uranium and that of uranium from plutonium are apparently higher than 104

Visceral hypersensitivity in female but not in male serotonin transporter knockout rats

BACKGROUND

Visceral hypersensitivity occurs in irritable bowel syndrome (IBS), particularly in women. Serotonin signaling, including reduced serotonin transporter (SERT) expression, may be disrupted in IBS patients. We studied SERT gene knockout (KO) rats to determine if they exhibited sex-related alterations in visceral sensitivity.

METHODS

We measured serotonin in the colonic mucosa using HPLC and amperometric microelectrode techniques. Visceral sensitivity was assessed using the electromyographic visceromotor response (VMR) in response to colorectal balloon distention (CRD). We studied the electrophysiologic properties of colon projecting sensory neurons in vitro using whole-cell recordings.

KEY RESULTS

Mucosal serotonin levels were not different among male and female WT and SERT KO rats. Serotonin oxidation currents in vitro were larger (P < 0.05) in tissues from male and female SERT KO compared with WT rats. Oxidation currents in male and female WT, but not SERT KO, rats were increased (P < 0.05) by the SERT inhibitor fluoxetine (1 μmol L(-1) ). The VMR to CRD was increased in female but not in male SERT KO rats (P < 0.05); this response varied with the estrous cycle. Colon projecting sensory neurons from female SERT KO rats fired more action potentials compared with neurons from female WT rats. There were no differences in action potential firing in neurons from male WT and SERT KO rats.

CONCLUSIONS & INFERENCES

Increased colonic extracellular serotonin in female SERT KO rats is associated with visceral hypersensitivity and hyperexcitability of colon projecting sensory neurons. The SERT KO rat is a model for studying interactions between serotonin, sex and visceral sensation.

The identification of c-Kit-positive cells in the intestine of chicken

The ultrastructure of the interstitial cells of Cajal (ICC) has been examined in birds, but the distribution of these cells remains obscure because a suitable marker is lacking. In the present study, the identification and expression of c-Kit-positive cells in the chicken intestine were demonstrated by means of in situ hybridization histochemistry and the expression of the c-Kit gene by real-time quantitative PCR. Two types of cells stained positive for c-Kit mRNA. The first group consisted of spindle-shaped or bipolar cells identified as ICC. The ICC were found at a variety of locations: at the level of the myenteric plexus between the circular and longitudinal muscle and intermingled with smooth muscle cells within muscle bundles in the circular and longitudinal muscle layers. The ICC were also identified along the submucosal layer. The second group was composed of round-shaped cells, which resembled mast cells. Mast cells were mainly found in the lamina propria region as well as in the submucosal layer. The expression of the c-Kit gene by real-time quantitative PCR revealed the expression of c-Kit mRNA throughout the lamina muscularis and mucosa of the intestine; however, the quantitation was variable in different regions. This study reveals conclusively for the first time the distribution of ICC, quantifies the expression of c-Kit mRNA in the intestine of adult chicken, and also compares the c-Kit-positive cell types morphologically.

Ultrastructural identification of different subtypes of interstitial cells of Cajal in the chicken ileum

Ultrastructural characteristics of different subtypes of interstitial cells of Cajal (ICC) remain unclear in birds; however, birds have significant economical and scientific notability. Our aim was to describe and classify ICC in the chicken gut. The ileum of normal adult Three Yellow broiler chickens (n=10) were studied by transmission electron microscopy (TEM). The ICC were spindle- or stellate-shaped with ramified cell processes. They had numerous mitochondria, abundant intermediate filaments, fusiform nuclei (oval or indented), with a dense band of peripheral heterochromatin, and formed close contacts by true gap junctions with each other and with neighboring smooth muscle cells (SMC). The ICC were in close contact with enteric nerves, but true gap junctions were not found between them. A new subtype of ICC located in the lamina propria mucosae has been discovered. Some of the ICC showed typical features of SMC, including a basal lamina, caveolae, and dense bodies. Lacking intermediate filaments and caveolae distinguished them from the fibroblast-like cells showing well-developed secretory organelles, including coated vesicles and a patchy basal lamina. The ultrastructural features and distribution of ICC in chicken intestine is similar to mammals. They may play similar key regulatory roles in gastrointestinal motility. The new subtype of ICC discovered in the lamina propria mucosae may play a role in the regulation of secretion and absorption.

Climatology of persistent deep stable layers in Utah's Salt Lake Valley, USA

Abstract. The characteristics of winter season persistent deep stable layers (PDSLs) over Utah's Salt Lake Valley are examined using 30-year twice daily rawinsonde soundings. The results highlight the basic climatological characteristics of the PDSLs, including the strengths of the inversion, the frequency of the occurrence, and the duration of the events. The data analyses also reveal linear trend, interannual variability, as well as the relationship between the interannual variability of PDSLs and the variability of large-scale circulations. Finally, the study investigates the large-scale atmosphere conditions accompanying the formation and destruction of the PDSL episodes.

Postnatal downregulation of inhibitory neuromuscular transmission to the longitudinal muscle of the guinea pig ileum

Neuromuscular transmission is crucial for normal gut motility but little is known about its postnatal maturation. This study investigated excitatory/inhibitory neuromuscular transmission in vitro using ileal nerve-muscle preparations made from neonatal (< or =48 h postnatal) and adult ( approximately 4 months postnatal) guinea pigs. In tissues from neonates and adults, nicotine (0.3-30 micromol L(-1)) contracted longitudinal muscle preparations in a tetrodotoxin (TTX) (0.3 micromol L(-1))-sensitive manner. The muscarinic receptor antagonist, scopolamine (1 micromol L(-1)), reduced substantially nicotine-induced contractions in neonatal tissues but not adult tissues. In the presence of N(omega)-nitro-l-arginine (NLA, 100 micromol L(-1)) to block nitric oxide (NO) mediated inhibitory neuromuscular transmission, scopolamine-resistant nicotine-induced contractions were revealed in neonatal tissues. NLA enhanced the nicotine-induced contractions in neonatal but not in adult tissues. Electrical field stimulation (20 V; 0.3 ms; 5-25 Hz, scopolamine 1 micromol L(-1) present) caused NLA and TTX-sensitive longitudinal muscle relaxations. Frequency-response curves in neonatal tissues were left-shifted compared with those obtained in adult tissues. Immunohistochemical studies revealed that NO synthase (NOS)-immunoreactivity (ir) was present in nerve fibres supplying the longitudinal muscle in neonatal and adult tissues. However, quantitative studies demonstrated that fluorescence intensity of NOS-ir nerve fibres was higher in neonatal than adult tissues. Nerve fibres containing substance P were abundant in longitudinal muscle in adult but not in neonatal tissues. Inhibitory neuromuscular transmission is relatively more effective in the neonatal guinea pig small intestine. Delayed maturation of excitatory motor pathways might contribute to paediatric motility disturbances.

Alpha2-adrenoceptors couple to inhibition of R-type calcium currents in myenteric neurons

Alpha2-adrenoceptors inhibit Ca2+ influx through voltage-gated Ca2+ channels throughout the nervous system and Ca2+ channel function is modulated following activation of some G-protein coupled receptors. We studied the specific Ca2+ channel inhibited following alpha2-adrenoceptor activation in guinea-pig small intestinal myenteric neurons. Ca2+ currents (I(Ca2+)) were studied using whole-cell patch-clamp techniques. Changes in intracellular Ca2+ (delta[Ca2+]i) in nerve cell bodies and varicosities were studied using digital imaging where Ca2+ influx was evoked by KCl (60 mmol L(-1)) depolarization. The alpha2-adrenoceptor agonist, UK 14 304 (0.01-1 micromol L(-1)) inhibited I(Ca2+) and delta[Ca2+]i; maximum inhibition of I(Ca2+) was 40%. UK 14 304 did not affect I(Ca2+) in the presence of SNX-482 or NiCl2 (R-type Ca2+ channel antagonists). UK 14 304 inhibited I(Ca2+) in the presence of nifedipine, omega-agatoxin IVA or omega-conotoxin, inhibitors of L-, P/Q- and N-type Ca2+ channels. UK 14 304 induced inhibition of I(Ca2+) was blocked by pertussis toxin pretreatment (1 microg mL(-1) for 2 h). Alpha2-adrenoceptors couple to inhibition of R-type Ca2+ channels via a pertussis toxin-sensitive pathway in myenteric neurons. R-type channels may be a target for the inhibitory actions of noradrenaline released from sympathetic nerves on to myenteric neurons.

The NCI/CIT microArray database (mAdb) system - bioinformatics for the management and analysis of Affymetrix and spotted gene expression microarrays

A scalable, modular, enterprise-level system for both microarray databasing and analysis over the Internet has been developed over the past four years by the National Cancer Institute's Center for Cancer Research in collaboration with NIH's Center for Information Technology. This completely Web-based system, called mAdb (for microArray database), is currently supporting over 810 registered users and collaborators at NIH and contains over 22,000 microarray experiments, making it one of the largest collections of microarray data in existence. In addition, the mAdb system has been ported for the Netherlands Cancer Institute, the Genome Institute of Singapore, and the CDC. This system has been used for a wide variety of scientific experiments spanning the range from cancer to studies of early development, and for human, mouse, rat, yeast, and numerous microbial organisms.

NF-kappa B activation mediates doxorubicin-induced cell death in N-type neuroblastoma cells

Neuroblastoma is the most common extracranial solid tumor of childhood. N-type neuroblastoma cells (represented by SH-SY5Y and IMR32 cell lines) are characterized by a neuronal phenotype. N-type cell lines are generally N-myc amplified, express the anti-apoptotic protein Bcl-2, and do not express caspase-8. The present study was designed to determine the mechanism by which N-type cells die in response to specific cytotoxic agents (such as cisplatin and doxorubicin) commonly used to treat this disease. We found that N-type cells were equally sensitive to cisplatin and doxorubicin. Yet death induced by cisplatin was inhibited by the nonselective caspase inhibitor z-Val-Ala-Asp-fluoromethylketone or the specific caspase-9 inhibitor N-acetyl-Leu-Glu-His-Asp-aldehyde, whereas in contrast, caspase inhibition did not prevent doxorubicin-induced death. Neither the reactive oxygen species nor the mitochondrial permeability transition appears to play an important role in this process. Doxorubicin induced NF-kappa B transcriptional activation in association with I-kappa B alpha degradation prior to loss of cell viability. Surprisingly, the antioxidant and NF-kappa B inhibitor pyrrolidine dithiocarbamate blocked doxorubicin-induced NF-kappa B transcriptional activation and provided profound protection against doxorubicin killing. Moreover, SH-SY5Y cells expressing a super-repressor form of I-kappa B were completely resistant to doxorubicin killing. Together these findings show that NF-kappa B activation mediates doxorubicin-induced cell death without evidence of caspase function and suggest that cisplatin and doxorubicin engage different death pathways to kill neuroblastoma cells.

Optimal management of postpartum hemorrhage

OBJECTIVE

To review the management of postpartum hemorrhage (PPH).

METHODS

Fifteen cases of severe PPH were retrospectively analyzed for clinical parameters and management.

RESULTS

Nine patients had a hysterectomy while selective arterial embolization was carried out in 7 cases. One patient had focus clearance. The main causes of postpartum hemorrhage requiring operative management were disseminated intravascular coagulation (DIC), uterine arteriovenous fistula and malformation, placental abnormality, uterine myoma and laceration.

CONCLUSION

Upon recognition of postpartum hemorrhage, the most effective management should be initiated. Every effort should be made to stabilize the patient and maintain her reproductive capability.

Comparative observation with MRI and pathology of brain edema at the early stage of severe burn

OBJECTIVE

To investigate the correlation between MRI features and pathology in brain edema at the early stage of severe burn (5 0% TBSA III degree) in dogs.

METHODS

Fifty-two dogs were randomized into control, simple b urn (SB), burn plus sodium lactate (BSL), and burn plus glucose solution groups (BGS). The manifestation of the brain of control group was compared with that of burn groups at 6, 12, 18 and 24 hours postburn with MRI and pathological examination (gross appearance, electron microscopy and light microscopy).

RESULTS

The earliest findings of brain edema were seen at 12 h ours after burn in BGS group, in which brain swelling was the main feature of MR I. The decrease of SIR on T(1)WI was not observed until it was exceeded 10%. Sig nal of T(2)WI increased by 8.29% at 24 hours after burn. It was difficult to distinguish the gray matter from the white matter at the boundary line, which became blurred later. Histological changes of brain edema were observed as early as 6 hours after burn, being accompanied by swelling of endothelial cells and peri-vescular astrocytes, and vacuolation took place in neurons at 12 hours after burn, with different degrees of necrosis of capillary endothelium, neurons, and axons. These changes became more marked with elapse of time. The BGS group showed the most obvious changes mentioned above at 24 hours after burn.

CONCLUSIONS

The model of the brain edema after severe burn has the feature of both vasogenic edema and cytotoxic edema on the MRI and pathology. Positive MRI findings lagged behind that of the pathomorphological changes.

Investigation of thrombomodulin and plasminogen activator inhibitor type-I in pregnancy induced hypertension and its clinical significance

OBJECTIVE

To measure the circulating levels of thrombomodulin (TM) and plasminogen activator inhibitor type-I (PAI-I) in women with pregnancy induced hypertension (PIH).

METHODS

Blood samples were drawn from 97 pregnant women in their third trimester, grouped as 25 mild PIH, 26 moderate PIH, 22 severe PIH and 24 normotensive healthy pregnant women for determining levels of TM by ELISA, PAI-I by colorimetric assay methods, and creatinine (Cr) in serum by biochemical method.

RESULTS

Circulating levels of TM, PAI-I and TM/Cr ratio increased with increasing severity of PIH. There were no significant differences between mild and normotensive pregnant women. The parameters were significantly changed in the moderate and severe PIH groups.

CONCLUSION

TM and PAI-I may serve as meaningful clinical markers for the assessment of the endothelial damage in PIH, which is very important in evaluating and following the development of PIH.

[The effects of the polysaccharides from Dermatocarpon miniatum on oxygen radicals and lipid peroxidation]

OBJECTIVE

To study the effects of Dermatocarpon miniatum (DEM) polysaccharides scavenging oxygen radicals and inhibiting lipid peroxidation.

METHODS

.OH was produced by Fenton reaction and O2-. was produced by the oxidation of pyrogallol. The inhibition to LPO was determined by the colorimetry for testing the relative content of MDA.

RESULTS

DEM polysaccharides could scavenge oxygen radical. The amounts of scavenging 50% (EC50) .OH was 1.72 mg/ml, the EC50 for O2-. was 2.12 mg/ml. DEM polysaccharides could also decrease the content of MDA.

CONCLUSION

DEM polysaccharides has the effects of scavenging oxygen radicals and the inhibition to LPO. Its activities showed positive correlation with the amounts.

Endogenous nitric oxide modulates myocardial oxygen consumption in canine right ventricle

The role of endogenous nitric oxide (NO) in modulating myocardial oxygen consumption (MVO2) is unclear, in part because of systemic and coronary hemodynamic effects of blocking NO release. This study evaluated the effect of NO on right ventricular MVO2 under controlled hemodynamic conditions. In 12 open-chest dogs, N(omega)-nitro-L-arginine methyl ester (L-NAME, 150 microg/min), a NO synthase (NOS) blocker, was infused into the right coronary artery. Heart rate and mean aortic pressure were constant. Right coronary blood flow and right ventricular MVO2 were measured at normal and elevated right coronary perfusion pressures (RCP) before and after L-NAME. To avoid effects of NO synthesis blockade on right coronary blood flow, which might have altered right ventricular MVO2, experiments, were conducted during adenosine-induced maximal coronary vasodilation. L-NAME did not affect right coronary blood flow (P = 0.51). However, L-NAME significantly increased right ventricular MVO2 (6% at RCP 100 mmHg, and 21% at RCP 180 mmHg). Right coronary blood flow varied with perfusion pressure (P < 0.02), and the elevation of MVO2 produced by L-NAME increased at higher flows (P < 0.04), consistent with the greater shear stress-mediated release of NO. These findings indicate that endogenous NO limits right ventricular MVO2.

Right ventricular oxygen supply/demand balance in exercising dogs

This is the first investigation of right ventricular (RV) myocardial oxygen supply/demand balance in a conscious animal. A novel technique developed in our laboratory was used to collect right coronary (RC) venous blood samples from seven instrumented, conscious dogs at rest and during graded treadmill exercise. Contributions of the RV oxygen extraction reserve and the RC flow reserve to exercise-induced increases in RV oxygen demand were measured. Strenuous exercise caused a 269% increase in RV oxygen consumption. Expanded arteriovenous oxygen content difference (A-V(Delta)O2) provided 58% of this increase in oxygen demand, and increased RC blood flow (RCBF) provided 42%. At less strenuous exercise, expanded A-V(Delta)O2 provided 60-80% of the required oxygen, and increases in RCBF were small and driven by increased aortic pressure. RC resistance fell only at strenuous exercise after the extraction reserve had been mobilized. Thus RC resistance was unaffected by large decreases in RC venous PO2 until an apparent threshold at 20 mmHg was reached. Comparisons of RV findings with published left ventricular data from exercising dogs demonstrated that increased O2 demand of the left ventricle is met primarily by increasing coronary flow, whereas increased O2 extraction makes a greater contribution to RV O2 supply.

Cognitive deficits following blast injury-induced neurotrauma: possible involvement of nitric oxide

Blast injuries, that is injuries caused by the complex pressure wave generated by some explosions, show increasing frequency throughout the world. However, whether blast injury is capable of inducing memory dysfunction has not been previously investigated. The present study examines the effects of blast injury-induced neurotrauma on memory deficit in rats. Furthermore, it is hypothesized that blast injury, stimulating nitric oxide production in the medial mesodiencephalic reticular formation and the dorsal hippocampus, both structures being involved in memory processing, may induce memory deficits. Prior to blast injury, Wistar rats were trained for an active avoidance task for 6 days. On day 6, rats that had acquired the avoidance response were subjected to whole-body blast injury, using a BT-I shock tube. Neurotrauma was confirmed by electron microscopical examination. At the completion of cognitive testing, rats were sacrificed at 3, 24 hours and 5 days after injury. The nitric oxide production in the brain structures was determined by the total nitrite/nitrate concentration, and by the expression of inducible nitric oxide synthase mRNA. The rats with blast injury revealed significant deficits in performance of the active avoidance task that persisted up to 5 days post-injury. Electron microscopical findings in both brain structures showed swellings of neurons, glial reaction, myelin debris, and increased pinocytotic activity on the fifth day following trauma. In blast injured rats, there was a significant elevation in total nitrite/nitrate levels 3 and 24 hours following injury which was comparable with the changes in the expression of inducible nitric oxide synthase mRNA. The results indicate that blast injury-induced neurotrauma is able to cause cognitive deficits.

[Pregnancy and its outcome in women with malformed uterus]

OBJECTIVE

To analyze the clinical characteristics of fertility and pregnancy in women with congenital uterine malformations and explore optimal treatments to improve the prognosis.

METHODS

A retrospective study was conducted on the fertility and obstetric outcome in 153 in patients with uterine malformations treated in our hospital from January 1984 to December 1998. Twenty-seven cases with other kinds of genital and/or urinary anomalies but with normal uterus was used as the control group.

RESULTS

The infertility rate was 22.2% (34/153). The miscarriage rate was 44.3% (86/194), preterm labor rate was 9.3% (18/194). Abnormal fetal presentation rate was as high as 28.4% (29/102), the cesarean section rate was 61.8% (63/102), perinatal mortality rate was 11.8% (12/102).

CONCLUSION

Women with congenital uterine malformation usually have higher incidence of infertility and complications during pregnancy and delivery. Bicornuate and septate uterus could be associated with poorer obstetric outcome.

Ultrastructural and functional characteristics of blast injury-induced neurotrauma

OBJECTIVE

The present study investigates whether whole-body or local (chest) exposure to blast overpressure can induce ultrastructural, biochemical, and cognitive impairments in the brain.

METHODS

Male Wistar rats were trained for an active avoidance task for 6 days. On day 6, rats that had acquired the avoidance response were subjected to whole-body blast injury (WBBI), generated by large-scale shock tube (n = 40); or local (chest) blast injury (LBI), induced by blast overpressure focused on the right middle thoracic region and generated by small-scale shock tube (n = 40) while the heads of animals were protected. At the completion of cognitive testing, rats were killed at 3 hours, 24 hours, and 5 days after injury. Ultrastructural changes in the hippocampus were analyzed electron microscopically. Parameters of oxidative stress (malondialdehyde and superoxide anion generation) and antioxidant enzyme defense (superoxide dismutase and glutathione peroxidase activity) were measured in the hippocampus to assess biochemical changes in the brain after blast.

RESULTS

Ultrastructural findings in animals subjected to WBBI or LBI demonstrated swellings of neurons, glial reaction, and myelin debris in the hippocampus. All rats revealed significant deficits in performance of the active avoidance task 3 hours after injury, but deficits persisted up to day 5 after injury only in rats subjected to WBBI. Oxidative stress development and altered antioxidant enzyme defense was observed in animals in both groups. Cognitive impairment and biochemical changes in the hippocampus were significantly correlated with blast injury severity in both WBBI and LBI groups.

CONCLUSION

These results confirm that exposure to blast overpressure induces ultrastructural and biochemical impairments in the brain hippocampus, with associated development of cognitive deficits.

[A quantitative pathological study on angiogenesis, vascular endothelial growth factor and inducible nitric oxide synthase in astrocytomas]

OBJECTIVE

To investigate whether the expression of vascular endothelial growth factor (VEGF) and inducible nitric oxide synthase (iNOS) are associated with angiogenesis and malignancy of astrocytomas.

METHODS

Immunohistochemistry, semiquantitation and image analysis were used to study the expression features of VEGF and iNOS in 61 cases of astrocytomas having follow-up data. Factor VIII related antigen (FVIII RAg) was also analysed in reflecting the epithelial cell amount and the microvessel density.

RESULTS

Microvessels in astrocytomas could be divided into seven types. The positive reaction areas and IA values of FVIIIRAg expression in the endothelium were significantly increased with the increase of tumor grade (P < 0.001) and VEGF labeling index (LI) (P < 0.05). The patients with high VEGF LIs (LI >or= 25%) had a poor prognosis. VEGF expression was significantly related to that of iNOS (P < 0.001), i.e., VEGF level was reduced along with the decrease of iNOS reaction.

CONCLUSION

Detection of FVIIIRAg could reflect the angiogenesis activities in astrocytomas. VEGF and iNOS could up-regulate each other to promote angiogenesis and are of importance in determining the malignancy degree of astrocytomas.

Dobutamine enhances both contractile function and energy reserves in hypoperfused canine right ventricle

Although the beta(1)-adrenergic agent dobutamine is used clinically to provide inotropic support to the failing myocardium, it could jeopardize the myocardium by depleting energy reserves. This investigation delineated the contractile and energetic effects of low versus high dobutamine doses in the hypoperfused right ventricular (RV) myocardium. The right coronary artery (RCA) of anesthetized dogs was cannulated for controlled perfusion with arterial blood, and regional RV contractile function was measured. RCA perfusion pressure was lowered from 100 mmHg baseline to 40 mmHg, and flow fell by 54%. At 15-min hypoperfusion, dobutamine was infused into the RCA at either 0.01 (low-dose dobutamine) or 0.06 microgram. kg(-1). min(-1) (high-dose dobutamine) for 15 min. Regional power (systolic segment shortening x isometric developed force x heart rate) stabilized at 63% of baseline during hypoperfusion. Low-dose dobutamine restored power to baseline but did not increase RV myocardial O(2) consumption (MVO(2)) and thus increased myocardial O(2) utilization efficiency (O(2)UE:power/MVO(2)). At 5 min, high-dose dobutamine enhancement of power was similar to that of low-dose dobutamine, but by 15 min, power and O(2)UE fell to untreated levels. Remarkably, low-dose dobutamine tripled cytosolic phosphorylation potential; in contrast, high-dose dobutamine lowered phosphorylation potential to 45% of the untreated value. Analyses of glucose uptake and glycolytic intermediates revealed sustained enhancement of glycolysis by low-dose dobutamine, but glycolysis became limited at glyceraldehyde 3-phosphate dehydrogenase during high-dose dobutamine treatment. In summary, low-dose dobutamine improved mechanical performance and efficiency of the hypoperfused RV myocardium while increasing myocardial energy reserves, but high-dose dobutamine failed to sustain improved function and depleted energy reserves. Dobutamine is capable of improving both contractile function and cellular energetics in the hypoperfused RV myocardium, but dosage should be carefully selected.