Increased reactive oxygen species in familial amyotrophic lateral sclerosis with mutations in SOD1

Amyotrophic lateral sclerosis (ALS) is a paralytic disorder characterized by degeneration of large motor neurons of the brain and spinal cord. A subset of ALS is inherited (familial ALS, FALS) and is associated with more than 70 different mutations in the SOD1 gene. Here we report that lymphoblast cell lines derived from FALS patients with 16 different mutations in SOD1 gene exhibit significant increase of intracellular reactive oxygen species (ROS) compared with sporadic ALS (SALS) and normal controls (spouses of ALS patients). The ROS generation did not correlate with SOD1 activity. Further, cells incubated with vitamin C, catalase or the flavinoid quercetin significantly reduced ROS in all groups. The catalase inhibitor 3-amino-1,2,4-triazole resulted in a ten-fold increase of ROS in all groups. Neither L-nitroarginine, a nitric oxide synthase inhibitor or vitamin E altered the ROS levels. Thus, these studies suggest that hydrogen peroxide (H(2)O(2)) is a major ROS elevated in FALS lymphoblasts and it may contribute to the degeneration of susceptible cells. Further, we postulate a mechanism by which increased H(2)O(2) could be generated by mutant SOD1.     

Relative pharmacokinetics of three amikacin brands in onco-hemotologic pediatric patients experiencing febrile neutropeina.

Three commercially available brands of amikacin were investigated in a parallel study design for the assessment of comparative pharmacokinetics in pediatric oncology patients with chemotherapy-induced neutropenic febrile episode. Amikacin concentration in serum samples was determined by fluorescence polarization immunoassay method using Abbott TDx system. Computer software, PK II was used for computation of pharmacokinetic parameters of amikacin. The serum concentration of all brands nonsignificantly (p > 0.05) varied at all time points, except at 1 and 2 hrs post dosing. At 1 hr post dosing, the serum concentration of brand II varied from rest of two brands. Whereas at 2 hr following I/V infusion, brands II and I were statistically different. Highest serum concentration of 38.69 +/- 1.45 microg/ml was observed in case of brand III while brands I and II showed lower but not significantly different serum concentration values, i.e., 36.30 +/- 1.65 and 37.89 +/- 1.32 microg/ml, respectively when compared with brand I. The other pharmacokinetic parameters of 3 brands found to have non-significant difference (P < 0.05) except, t(1/2)alpha and Cl of brands I and II that deviated statistically significant (p < 0.01). The relative bioavailability of brand II and III as compared with brand I, considered as standard 86.17 and 96.86%, respectively falls within the accepted limits of +/- 20% required for the bioequivalence of any two brands. Based upon findings of the present study, all these brands may be used interchangeably in oncology patients. Further studies, however are needed to determine whether the statistically elevated Cl value in brand II is of any clinical significance.     

Exposure of melanoma cells to dacarbazine results in enhanced tumor growth and metastasis in vivo.

PURPOSE: In recent years, the incidence of cutaneous melanoma has increased more than that of any other cancer. Dacarbazine is considered the gold standard for treatment, having a response rate of 15% to 20%, but most responses are not sustained. Previously, we have shown that short exposure of primary cutaneous melanoma cells to dacarbazine resulted in the upregulation of interleukin-8 (IL-8) and vascular endothelial growth factor (VEGF). The purpose of the present study was to determine how long-term exposure of melanoma cells to dacarbazine would affect their tumorigenic and metastatic potential in vivo. MATERIALS AND METHODS: The primary cutaneous melanoma cell lines SB2 and MeWo were repeatedly exposed in vitro to increasing concentrations of dacarbazine, and dacarbazine-resistant cell lines SB2-D and MeWo-D were selected and examined for their ability to grow and metastasize in nude mice. RESULTS: The dacarbazine-resistant cell lines SB2-D and MeWo-D exhibited increased tumor growth and metastatic behavior in vivo. This increase could be explained by the activation of RAF, MEK, and ERK, which led to the upregulation of IL-8 and VEGF. More IL-8, VEGF, matrix metalloproteinase-2 (MMP-2), and microvessel density (CD-31) were found in tumors produced by SB2-D and MeWo-D in vivo than in those produced by their parental counterparts. No mutations were observed in BRAF. CONCLUSION: Our results have significant clinical implications. Treatment of melanoma patients with dacarbazine could select for a more aggressive melanoma phenotype. We propose that combination treatment with anti-VEGF/IL-8 or MEK inhibitors may potentiate the therapeutic effects of dacarbazine.     

Epidermal growth factor receptor tyrosine kinase inhibitor does not improve paclitaxel effect in an orthotopic mouse model of lung cancer.

PURPOSE: The purpose is to evaluate whether inhibition of epidermal growth factor receptor (EGFR) activation by PKI166, an EGFR-tyrosine kinase inhibitor, affects growth of human lung cancer implanted orthotopically into the lungs of nude mice. EXPERIMENTAL DESIGN: Lungs of mice were injected with NCI-H358 human bronchioloalveolar cancer cells. In three experiments, groups of mice (n = 10 per group) were randomized 7 days after tumor implantation to receive one of the following treatments: i.p. paclitaxel 100 or 200 microg (4 or 8 mg/kg) once per week, oral PKI166 100 or 200 mg/kg three times per week, paclitaxel plus PKI166, or i.p. saline and oral PKI166-vehicle (control) for 5 weeks. Mice were killed 6.5 to 8 weeks after tumor implantation. The experiments were repeated with PC14PE6 human lung adenocarcinoma cells to assess effect on survival. RESULTS: Immunohistochemical analyses revealed the expression and phosphorylation of EGFR in the growing tumors. Treatment with PKI166 alone or in combination with paclitaxel diminished activation of EGFR on tumor cells, yet maximal therapeutic effect was observed in mice treated with paclitaxel alone. Activated mitogen-activated protein kinase and basic fibroblast growth factor expression were similar in all treatment groups. Survival in mice treated with the combination of paclitaxel and PKI166 was shorter than in those treated with paclitaxel alone. CONCLUSIONS: Our results suggest that concurrent administration of EGFR-tyrosine kinase inhibitor and chemotherapy is equivalent and may indeed be inferior to chemotherapy alone, even if EGFR is functional and its phosphorylation effectively inhibited. Our data show that the interaction of EGFR-TKIs and chemotherapy is complex and suggest that other growth factors may activate the downstream signaling events.     

The effect of intensive care on in-hospital survival

Intensive Care Units (ICU) are one of the most powerful and expensive technologies within inpatient care. However, its effect on survival is still an issue under discussion. The objective of this paper is to assess the effect of General ICU on in-hospital survival. We assessed the effect of ICU on survival using Linear and Probit regressions. Since admission to IC is not random and depends on unobserved (to the researcher) heterogeneity, we reassessed the IC effect by Instrumental Variables (IV) and Bivariate Probit techniques, using crowding in the IC unit as an instrument. The results show that a simple Probit of the IC effect on survival is 7–10 percentage-points (pts). The IV estimate of the IC effect on survival is 21–34 pts, and the Bivariate Probit estimate is 17–21 pts. We conclude that although admitted patients are at lower risk of death, as determined by their observable (to the researcher) characteristics, controlling for observable differences, those with a higher unobserved risk of mortality are more likely to be admitted. The implications for an optimal admission policy are discussed.     

Evidence for selective expression of the p53 codon 72 polymorphs: implications in cancer development.

Polymorphism at codon 72 of p53 results in either the arginine or proline form of p53, whose functional significance in carcinogenesis is controversial. We have investigated if the expression of these p53 polymorphs is selectively regulated, using mRNA from peripheral blood of healthy Asian (Chinese) and the Caucasian (Polish) arginine/proline (arg/pro) heterozygote subjects. Asians were found to preferentially express the pro allele whereas the Caucasians preferentially express the arg allele. On the contrary, about 75% of the heterozygote Chinese breast cancer patients preferentially expressed the arg allele, which rarely contained any somatic mutations. Moreover, histologically normal tissues from Chinese heterozygote breast cancer patients showed selective expression of the arg allele, in contrast to the preferential expression of the pro allele in heterozygote healthy normal breast tissues. Together, the data suggest that the expression of the different p53 polymorphs is selectively regulated in different ethnic populations, and that the arg allele is activated during cancer development in Asians. Thus, the expression status of the p53 polymorphs, rather than the genotypic status, might be a useful indicator for cancer susceptibility.     

Feedback and feedforward adaptation to visuomotor delay during reaching and slicing movements

It has been suggested that the brain and in particular the cerebellum and motor cortex adapt to represent the environment during reaching movements under various visuomotor perturbations. It is well known that significant delay is present in neural conductance and processing; however, the possible representation of delay and adaptation to delayed visual feedback has been largely overlooked. Here we investigated the control of reaching movements in human subjects during an imposed visuomotor delay in a virtual reality environment. In the first experiment, when visual feedback was unexpectedly delayed, the hand movement overshot the end‐point target, indicating a vision‐based feedback control. Over the ensuing trials, movements gradually adapted and became accurate. When the delay was removed unexpectedly, movements systematically undershot the target, demonstrating that adaptation occurred within the vision‐based feedback control mechanism. In a second experiment designed to broaden our understanding of the underlying mechanisms, we revealed similar after‐effects for rhythmic reversal (out‐and‐back) movements. We present a computational model accounting for these results based on two adapted forward models, each tuned for a specific modality delay (proprioception or vision), and a third feedforward controller. The computational model, along with the experimental results, refutes delay representation in a pure forward vision‐based predictor and suggests that adaptation occurred in the forward vision‐based predictor, and concurrently in the state‐based feedforward controller. Understanding how the brain compensates for conductance and processing delays is essential for understanding certain impairments concerning these neural delays as well as for the development of brain–machine interfaces.     

Anterior abdominal wall ‘peritoneal recess’: cause for pseudoherniation of small bowel resulting in chronic abdominal pain

A middle-aged patient presented with intermittent chronic abdominal pain without any obvious cause. Computed tomography detected a hernia (presumed to be the cause of the patient’s symptoms) without any obvious lump on examination. A laparoscopy was performed to repair the hernia. This revealed a left-sided unilateral ‘peritoneal recess’ at the level of the arcuate line extending medial to the linea semilunaris. No extraperitoneal sac or defect was noted in the rectus sheath or in the muscle, nor were any contents present in the recess at the time of the laparoscopy. We believe the bowel was being trapped intermittently in this space, causing the abdominal symptoms.     

Intrahepatic cholangiocarcinoma: current management and emerging therapies

Introduction: Intrahepatic cholangiocarcinoma (iCCA) is a malignancy with an increasing incidence and a high-case fatality. While surgery offers the best hope at long-term survival, only one-third of tumors are amenable to surgical resection at the time of the diagnosis. Unfortunately, conventional chemotherapy offers limited survival benefit in the management of unresectable or metastatic disease. Recent advances in understanding the molecular pathogenesis of iCCA and the use of next-generation sequencing techniques have provided a chance to identify ‘target-able’ molecular aberrations. These novel molecular therapies offer the promise to personalize therapy for patients with iCCA and, in turn, improve the outcomes of patients.

Area covered: We herein review the current management options for iCCA with a focus on defining both established and emerging therapies.

Expert commentary: Surgical resection remains as an only hope for cure in iCCA patients. However, frequently the diagnosis is delayed till advanced stages when surgery cannot be offered; signifying the urge for specific diagnostic tumor biomarkers and targeted therapies. New advances in genomic profiling have contributed to a better understanding of the landscape of molecular alterations in iCCA and offer hope for the development of novel diagnostic biomarkers and targeted therapies.