The use of electrical cardiometry for continuous cardiac output monitoring in preterm neonates: a validation study

BACKGROUND

Electrical cardiometry (EC) is a continuous noninvasive method for measuring cardiac output (CO), but there are limited data on premature infants. We evaluated the utility of EC monitoring by comparing the results obtained using EC to measurements of CO and systemic blood flow using echocardiography (ECHO).

METHODS

In this prospective observational study, 40 preterm neonates underwent 108-paired EC and ECHO measurements.

RESULTS

There were correlations between EC-CO and left ventricular output (LVO, p < 0.005) and right ventricular output (RVO, p < 0.005) but not with superior vena cava (r = 0.093, p = 0.177). Both RVO and LVO correlated with EC with and without a hemodynamically significant ductus arteriosus (p = 0.001 and 0.008, respectively). The level of agreement was decreased in infants ventilated by high-frequency oscillation ventilators (HFOV). The bias in HFOV was also positive compared with the negative biases found in other modes of ventilation.

CONCLUSION

Given the correlation of EC with LVO, RVO, and lack of confounding effects of the ductus, our results suggest that EC has promise for trending CO in the preterm infant. However, given the limitations with mode of ventilation and the lack of correlation at low LVO values, further study is needed before this technology can be for routine use.

Evaluation of SWI in children with sickle cell disease

BACKGROUND AND PURPOSE

SWI is a powerful tool for imaging of the cerebral venous system. The SWI venous contrast is affected by blood flow, which may be altered in sickle cell disease. In this study, we characterized SWI venous contrast in patients with sickle cell disease and healthy control participants and examined the relationships among SWI venous contrast, and hematologic variables in the group with sickle cell disease.

MATERIALS AND METHODS

A retrospective review of MR imaging and hematologic variables from 21 patients with sickle cell disease and age- and sex-matched healthy control participants was performed. A Frangi vesselness filter was used to quantify the attenuation of visible veins from the SWI. The normalized visible venous volume was calculated for quantitative analysis of venous vessel conspicuity.

RESULTS

The normalized visible venous volume was significantly lower in the group with sickle cell disease vs the control group (P < .001). Normalized visible venous volume was not associated with hemoglobin, percent hemoglobin F, percent hemoglobin S, absolute reticulocyte count, or white blood cell count. A hypointense arterial signal on SWI was observed in 18 of the 21 patients with sickle cell disease and none of the 21 healthy control participants.

CONCLUSIONS

This study demonstrates the variable and significantly lower normalized visible venous volume in patients with sickle cell disease compared with healthy control participants. Decreased venous contrast in sickle cell disease may reflect abnormal cerebral blood flow, volume, velocity, or oxygenation. Quantitative analysis of SWI contrast may be useful for investigation of cerebrovascular pathology in patients with sickle cell disease, and as a tool to monitor therapies. However, future studies are needed to elucidate physiologic mechanisms of decreased venous conspicuity in sickle cell disease.

Effects of feeding diets containing highly peroxidized distillers dried grains with solubles and increasing vitamin E levels to wean-finish pigs on growth performance, carcass characteristics, and pork fat composition

Lipid peroxidation in animal feed can negatively affect growth performance and meat quality. Weanling pigs (n = 432; BW = 6.6 ± 0.4 kg) were used to evaluate the effects of feeding peroxidized distillers dried grains with solubles (DDGS) with 3 levels of vitamin E (α-tocopheryl acetate) on growth performance, carcass composition, fatty acid composition of pork fat, and lipid peroxidation in LM. The DDGS source used in this study contained the highest thiobarbituric acid reactive substances (TBARS) value, peroxide value, and total S content (5.2 ng malondialdehyde/mg oil, 84.1 mEq/kg oil, and 0.95%, respectively) among 30 DDGS sources sampled. Pens within blocks were assigned randomly to 1 of 6 diets in a 2 × 3 factorial arrangement of treatments with 8 pens per treatment and 9 pigs per pen. Pigs were fed a corn-soybean meal (CON) or 30% peroxidized DDGS (Ox-DDGS) diets with 3 levels of vitamin E: none supplemented (No-E), NRC (1X-E), or 10X NRC (10X-E). Compared to CON, inclusion of 30% Ox-DDGS in diets reduced (P < 0.001) final BW (110 vs. 107 kg), overall ADG (0.76 vs. 0.74 kg/d), and G:F (0.39 vs. 0.37). Increasing dietary vitamin E concentrations improved G:F (P = 0.03) of pigs fed 10X-E and 1X-E vs. No-E diets (0.39 and 0.39 vs. 0.38, respectively). Hot carcass weight, dressing percentage, backfat depth, and LM area were reduced (P < 0.01) in pigs fed Ox-DDGS compared to CON, but percentage of fat-free carcass lean was not affected. Feeding Ox-DDGS increased (P < 0.001) PUFA concentration, particularly linoleic acid (P < 0.001), and iodine value (P < 0.001) in belly fat and backfat compared to pigs fed CON. Dietary vitamin E levels did not affect fatty acid profiles in belly or back fat. Loin muscle TBARS were measured to determine the lipid peroxidation level in pork loins. Although pigs were fed a Ox-DDGS source in this study, TBARS in LM were similar between Ox-DDGS and CON treatments. There was no interaction between Ox-DDGS and dietary vitamin E concentration in LM TBARS. Alpha-tocopherol concentration in LM was greater (P < 0.001) in 10X-E than No-E or 1X-E dietary treatments. Compared to CON, feeding Ox-DDGS increased α-tocopherol concentration in LM of pigs fed No-E (1.0 vs. 3.1 mg/kg; P = 0.005) but not in those fed 1X-E or 10X-E. These results indicate that feeding diets containing 30% Ox-DDGS to wean-finish pigs may negatively affect growth performance, but supplementation of additional vitamin E in the diet did not counteract these effects.

Evaluation of lipid peroxidation level in corn dried distillers grains with solubles

Lipid peroxidation in feed can negatively affect animal health, growth performance, and meat quality. The objective of this study was to determine the lipid peroxidation level in corn dried distillers grains with solubles (DDGS) samples from 31 U.S. ethanol plants and compare results with a corn sample obtained from a corn processing plant. Lipids from each sample were extracted with hexane and analyzed for peroxide value (PV) and thiobarbituric acid reactive substances (TBARS). Peroxide values of DDGS samples ranged from 4.2 to 84.1 milliequivalents (meq)/kg oil (CV = 97.5%). The greatest PV among DDGS samples was 27 times greater than that of the corn sample (3.1 meq/kg oil). The TBARS values for DDGS samples ranged from 1.0 to 5.2 ng malondialdehyde (MDA) equivalents/mg oil (CV = 43.6%). The DDGS sample with the greatest TBARS value was 25 times greater than that of the corn sample (0.2 ng MDA equivalents/mg oil). Color of DDGS samples was measured by Minolta L*, a*, and b*, corresponding to the degree of lightness, redness, and yellowness, respectively. Correlations between PV, TBARS, and color were determined. Values of PV and TBARS were correlated positively (r = 0.81; P < 0.001). Both TBARS and PV were correlated negatively with L* (r = -0.73; P < 0.001, and r = -0.63; P < 0.001, respectively) and b* (r = -0.67; P < 0.001, and r = -0.57; P < 0.001, respectively), which suggests that darker and less yellow-colored DDGS samples were more likely to have a greater lipid peroxidation level, as measured by TBARS and PV, compared with lighter or more yellow-colored DDGS samples. However, a* was not correlated with either PV (P = 0.97) or TBARS (P = 0.66). These results indicate that color can be a preliminary indicator of lipid peroxidation level in DDGS, but a more reliable assessment of peroxidation level is achieved by measuring PV and TBARS.

Therapeutic destruction of insulin receptor substrates for cancer treatment

Insulin receptor substrates 1 and 2 (IRS1/2) mediate mitogenic and antiapoptotic signaling from insulin-like growth factor 1 receptor (IGF-IR), insulin receptor (IR), and other oncoproteins. IRS1 plays a central role in cancer cell proliferation, its expression is increased in many human malignancies, and its upregulation mediates resistance to anticancer drugs. IRS2 is associated with cancer cell motility and metastasis. Currently, there are no anticancer agents that target IRS1/2. We present new IGF-IR/IRS-targeted agents (NT compounds) that promote inhibitory Ser-phosphorylation and degradation of IRS1 and IRS2. Elimination of IRS1/2 results in long-term inhibition of IRS1/2-mediated signaling. The therapeutic significance of this inhibition in cancer cells was shown while unraveling a novel mechanism of resistance to B-RAF(V600E/K) inhibitors. We found that IRS1 is upregulated in PLX4032-resistant melanoma cells and in cell lines derived from patients whose tumors developed PLX4032 resistance. In both settings, NT compounds led to the elimination of IRS proteins and evoked cell death. Treatment with NT compounds in vivo significantly inhibited the growth of PLX4032-resistant tumors and displayed potent antitumor effects in ovarian and prostate cancers. Our findings offer preclinical proof-of-concept for IRS1/2 inhibitors as cancer therapeutics including PLX4032-resistant melanoma. By the elimination of IRS proteins, such agents should prevent acquisition of resistance to mutated-B-RAF inhibitors and possibly restore drug sensitivity in resistant tumors.

Galectin-3 contributes to melanoma growth and metastasis via regulation of NFAT1 and autotaxin

Melanoma is the deadliest form of skin cancer in which patients with metastatic disease have a 5-year survival rate of less than 10%. Recently, the overexpression of a β-galactoside binding protein, galectin-3 (LGALS3), has been correlated with metastatic melanoma in patients. We have previously shown that silencing galectin-3 in metastatic melanoma cells reduces tumor growth and metastasis. Gene expression profiling identified the protumorigenic gene autotaxin (ENPP2) to be downregulated after silencing galectin-3. Here we report that galectin-3 regulates autotaxin expression at the transcriptional level by modulating the expression of the transcription factor NFAT1 (NFATC2). Silencing galectin-3 reduced NFAT1 protein expression, which resulted in decreased autotaxin expression and activity. Reexpression of autotaxin in galectin-3 silenced melanoma cells rescues angiogenesis, tumor growth, and metastasis in vivo. Silencing NFAT1 expression in metastatic melanoma cells inhibited tumor growth and metastatic capabilities in vivo. Our data elucidate a previously unidentified mechanism by which galectin-3 regulates autotaxin and assign a novel role for NFAT1 during melanoma progression.

Expression of Id-1 is regulated by MCAM/MUC18: a missing link in melanoma progression

The acquisition of the metastatic melanoma phenotype is associated with increased expression of the melanoma cell adhesion molecule MCAM/MUC18 (CD146). However, the mechanism by which MUC18 contributes to melanoma metastasis remains unclear. Herein, we stably silenced MUC18 expression in two metastatic melanoma cell lines, A375SM and C8161, and conducted cDNA microarray analysis. We identified and validated that the transcriptional regulator, inhibitor of DNA binding-1 (Id-1), previously shown to function as an oncogene in several malignancies, including melanoma, was downregulated by 5.6-fold following MUC18 silencing. Additionally, we found that MUC18 regulated Id-1 expression at the transcriptional level via ATF-3, which itself was upregulated by 6.9-fold in our cDNA microarray analysis. ChIP analysis showed increased binding of ATF-3 to the Id-1 promoter after MUC18 silencing. To complement these studies, we rescued the expression of MUC18, which reversed the expression patterns of Id-1 and ATF-3. Moreover, we showed that MUC18 promotes melanoma invasion through Id-1, as overexpression of Id-1 in MUC18-silenced cells resulted in increased MMP-2 expression and activity. To our knowledge, this is the first demonstration that MUC18 is involved in cell signaling regulating the expression of Id-1 and ATF-3, thus contributing to melanoma metastasis.

The expression of Sirtuins 1 and 4 in peripheral blood leukocytes from patients with type 2 diabetes

This study was designed to investigate the relationship between SIRTs 1 and 4 in peripheral blood leukocytes (PBLs) and human type 2 diabetes mellitus (T2DM). SIRTs 1 and 4 have been confirmed to be associated with homeostasis of glucose/lipid metabolism, but their roles in T2DM are still poorly understood. Peripheral blood and biochemical data were collected from 52 healthy individuals (normal control group, NC group) and 113 cases of T2DM patients. Immunocytochemical staining was used to detect SIRT1 and SIRT4 and reverse transcription polymerase chain reaction (RT-PCR) was used to detect SIRT1 or SIRT4 mRNA levels in PBLs. Immunocytochemical staining showed that SIRT1 is expressed in both nucleus and cytoplasm, and SIRT4 in the cytoplasm of granulocytes and monocytes. No SIRT1 or SIRT4 was found in lymphocytes. RT-PCR showed that SIRT1 and SIRT4 mRNA levels in T2DM group were lower than those in NC group (P&lt;0.01). Correlation analysis showed that there is a negative correlation between SIRTs 1 and 4 and fasting plasma glucose (FPG) (P&lt;0.05) (r= -0.161 and -0.156), a positive correlation between SIRT4 mRNA levels and triglyceride (TG)/lipoprotein a (LPa) levels (P&lt;0.05), and a negative correlation between SIRT4 mRNA levels and high density lipoprotein cholesterol (HDL) (P&lt;0.05). SIRTs 1 and 4 may have a role in the pathogenesis of T2DM and their expression in granulocytes and monocytes may indirectly reflect the homeostasis of glucose/lipid metabolism in T2DM.