A1152D mutation of the Na+ channel causes paramyotonia congenita and emphasizes the role of DIII/S4–S5 linker in fast inactivation

Missense mutations in the human skeletal muscle Na⁺ channel α subunit (hSkM1) are responsible for a number of muscle excitability disorders. Among them, paramyotonia congenita (PC) is characterized by episodes of muscle stiffness induced by cold and aggravated by exercise. We have identified a new PC-associated mutation, which substitutes aspartic acid for a conserved alanine in the S4–S5 linker of domain III (A1152D). This residue is of particular interest since its homologue in the rat brain type II Na⁺ channel has been suggested as an essential receptor site for the fast inactivation particle. To identify the biophysical changes induced by the A1152D mutation, we stably expressed hSkM1 mutant or wild-type (WT) channels in HEK293 (human embryonic kidney) cells, and recorded whole-cell Na⁺ currents with the patch-clamp technique. Experiments were performed both at 21 and 11°C to better understand the sensitivity to cold of paramyotonia. The A1152D mutation disrupted channel fast inactivation. In comparison to the WT, mutant channels inactivated with slower kinetics and displayed a 5 mV depolarizing shift in the voltage dependence of the steady-state. The other noticeable defect of A1152D mutant channels was an accelerated rate of deactivation from the inactivated state. Decreasing temperature by 10°C amplified the differences in channel gating kinetics between mutant and WT, and unveiled differences in both the sustained current and channel deactivation from the open state. Overall, cold-exacerbated mutant defects may result in a sufficient excess of Na⁺ influx to produce repetitive firing and myotonia. In the light of previous reports, our data point to functional as well as phenotypic differences between mutations of conserved S4–S5 residues in domains II and III of the human skeletal muscle Na⁺ channel.     

Primary Hepatic Lymphoma After Lung Transplantation: A Report of 2 Cases

BackgroundDiffuse large B-cell lymphoma (DLBCL) is the most common subtype of non–Hodgkin lymphoma in the posttransplant setting. Treatment is based on chemotherapy; surgery is still debated and should be performed in very select cases.MethodsWe observed 2 patients out of 300 who underwent lung transplantation in the Nouvel Hopital Civil between 2013 and 2019 with primary hepatic lymphoma. Chemotherapy with a rituximab-cyclophosphamide, hydroxydaunorubicin, vincristine, prednisone protocol was performed in all patients. Mycophenolate mofetil was interrupted before treatment, and everolimus was introduced after chemotherapy by associating tacrolimus withdrawal.ResultsOne patient showed complete remission; after 7 years, no recurrence has been noticed. The second is still undergoing chemotherapy with no signs of disease progression.ConclusionsDLBCL risk is higher in solid organ transplant recipients than in the general population. Primary hepatic lymphoma diagnosis is often difficult and based on histologic findings after initial clinical and radiological suspicion of primary or secondary liver neoplasia. Diagnosis is challenging because no clinical, radiological, or biological features exist. Biopsy is always indicated for histologic confirmation. Chemotherapy is the mainstay of therapy, but surgery may be indicated in very select patients.     

Activation of AMP-activated protein kinase in the liver: a new strategy for the management of metabolic hepatic disorders

It is now becoming evident that the liver has an important role in the control of whole body metabolism of energy nutrients. In this review, we focus on recent findings showing that AMP-activated protein kinase (AMPK) plays a major role in the control of hepatic metabolism. AMPK integrates nutritional and hormonal signals to promote energy balance by switching on catabolic pathways and switching off ATP-consuming pathways, both by short-term effects on phosphorylation of regulatory proteins and by long-term effects on gene expression. Activation of AMPK in the liver leads to the stimulation of fatty acid oxidation and inhibition of lipogenesis, glucose production and protein synthesis. Medical interest in the AMPK system has recently increased with the demonstration that AMPK could mediate some of the effects of the fat cell-derived adiponectin and the antidiabetic drugs metformin and thiazolidinediones. These findings reinforce the idea that pharmacological activation of AMPK may provide, through signalling and metabolic and gene expression effects, a new strategy for the management of metabolic hepatic disorders linked to type 2 diabetes and obesity.     

Testicular degeneration in three patients with the persistent müllerian duct syndrome

The presistent Müllerian duct syndrome, characterized by the presence of uterus and tubes in males, is a familial disorder due to defects of synthesis or action of anti-Müllerian hormone, a Sertoli cell glycoprotein responsible for the regression of Müllerian derivatives in normal male fetuses. Patients are normally virilized and testicular production of testosterone is normal. Both testes my be cryptorchild; alternatively, one may be descended into the inguinal canal or scrotum, together with the Müllerian derivatives, a condition known as hernia uteri inguinalis. We have recently observed three patients affected by the presistent Müllerian duct syndrome who experienced progressive degeneration of testicular tissue. In two, functional testicular tissue was still present some months after birth, but deteriortated progressively later. In one patient, testicular tissue was already absent at birth, but the normal virilization of external genitalia indicated that testicular degeneration must have occurred lat during fetal life, after the expected time of regression of male Müllerian ducts.Conclusion The high incidence of degeneration of testicular tissue in the presistent Müllerian duct syndrome could be indirectly linked to anatomical abnormalities which could favour testicular torsion, known to induce testicular regression.     

Characterization of gastrin-induced proangiogenic effects in vivo in orthotopic U373 experimental human glioblastomas and in vitro in human umbilical vein endothelial cells.

PURPOSE: This study aims to investigate the role of gastrin-17 (G17) on angiogenesis features in gliomas both in vitro and in vivo. EXPERIMENTAL DESIGN: The influences of G17 and G17 receptor antagonists were characterized in vitro in terms of angiogenesis on human umbilical vein endothelial cell (HUVEC) tubulogenesis processes on Matrigel and in vivo with respect to U373 orthotopic glioma xenografts. The influence of phosphatidylinositol 3'-kinase, protein kinase C, and nuclear factor-kappaB inhibitors was characterized in vitro on G17-mediated HUVEC tubulogenesis. G17-mediated release of interleukin (IL)-8 from HUVECs and G17-induced modifications in nuclear factor-kappaB DNA binding activity were characterized by means of specific enzyme-linked immunosorbent assays. The influence of G17 on E- and P-selectin expression was determined by means of computer-assisted microscopy, whereas the influence of E- and P-selectin on HUVEC migration was approached by means of antisense oligonucleotides. The chemotactic influence of G17 and IL-8 on HUVEC migration was characterized by means of computer-assisted videomicroscopy with Dunn chambers. RESULTS: Messenger RNAs for cholecystokinin (CCK)A, CCKB, and CCKC receptors were present in HUVECs and microvessels dissected from a human glioblastoma. Whereas G17 significantly increased the levels of angiogenesis in vivo in the U373 experimental glioma model and in vitro in the HUVECs, the CCKB receptor antagonist L365,260 significantly counteracted the G17-mediated proangiogenic effects. G17 chemoattracted HUVECs, whereas IL-8 failed to do so. IL-8 receptor alpha (CXCR1) and IL-8 receptor beta (CXCR2) mRNAs were not detected in these endothelial cells. Gastrin significantly (but only transiently) decreased the level of expression of E-selectin, but not P-selectin, whereas IL-8 increased the expression of E-selectin. Specific antisense oligonucleotides against E- and P-selectin significantly decreased HUVEC tubulogenesis processes in vitro on Matrigel. CONCLUSIONS: The present study shows that gastrin has marked proangiogenic effects in vivo on experimental gliomas and in vitro on HUVECs. This effect depends in part on the level of E-selectin activation, but not on IL-8 expression/release by HUVECs.     

How to optimize physicians' communication skills in cancer care: results of a randomized study assessing the usefulness of posttraining consolidation workshops.

PURPOSE: Although there is wide recognition of the usefulness of improving physicians' communication skills, no studies have yet assessed the efficacy of post-training consolidation workshops. This study aims to assess the efficacy of six 3-hour consolidation workshops conducted after a 2.5-day basic training program. METHODS: Physicians, after attending the basic training program, were randomly assigned to consolidation workshops or to a waiting list. Training efficacy was assessed through simulated and actual patient interviews that were audiotaped at baseline and after consolidation workshops for the consolidation-workshop group, and approximately 5 months after the end of basic training for the waiting-list group. Communication skills were assessed according to the Cancer Research Campaign Workshop Evaluation Manual. Patients' perceptions of communication skills improvement were assessed using a 14-item questionnaire. RESULTS: Sixty-three physicians completed the training program. Communication skills improved significantly more in the consolidation-workshop group compared with the waiting-list group. In simulated interviews, group-by-time repeated measures analysis of variance showed a significant increase in open and open directive questions (P =.014) and utterances alerting patients to reality (P =.049), as well as a significant decrease in premature reassurance (P =.042). In actual patient interviews, results revealed a significant increase in acknowledgements (P =.022) and empathic statements (P =.009), in educated guesses (P =.041), and in negotiations (P =.008). Patients interacting with physicians who benefited from consolidation workshops reported higher scores concerning their physicians' understanding of their disease (P =.004). CONCLUSION: Consolidation workshops further improve a communication skills training program's efficacy and facilitate the transfer of acquired skills to clinical practice.     

Factors associated with liver biopsy performance in HCV-HIV coinfected injecting drug users with HCV viremia: Results from a five-year longitudinal assessment

The last international consensus conference about hepatitis C virus (HCV) treatment emphasized the importance of treatment for persons coinfected with HCV and human immunodeficiency virus (HIV). As liver biopsy precedes treatment, we aimed to identify factors associated with the performance of liver biopsy among HIV-HCV coinfected drug users during a 5-year follow-up to study their access to HCV treatment. Of the 296 patients followed in the HIV hospital departments of Nice and Marseilles and with retrievable records about HCV diagnosis and care, 166 were eligible for analysis having had detectable HCV RNA at least once during the study period. Overall, 45.2% of patients underwent liver biopsy during follow-up. Using proportional hazard models, predictors of having had a liver biopsy were high social support, complete abstinence from drug injection, and lack of immunosuppression as well as male gender, no history of multiple incarcerations, more recent onset of drug use, and an increase of liver enzyme levels. These results suggest that specific efforts should be devoted to HIV-HCV coinfected drug users to assist with stabilizing these patients to optimize their access to HCV care whenever possible. The MANIF 2000 study group includes C. Boirot, A. D. Bouhnik, M. P. Carrieri, J. P. Cassuto, M. Chesney, P. Dellamonica, P. Dujardin, S. Duran, J. G. Fuzibet, H. Gallais, J. A. Gastaut, G. Lepeu, D. A. Loundou, C. Marimoutou, D. Mechali, J. P. Moatti, J. Moreau, M. Nègre, Y. Obadia, I. Poizot-Martin, C. Pradier, D. Rey, C. Rouzioux, A. Sobel, B. Spire, F. Trémolières, and D. Vlahov.     

Phase I combining a P-glycoprotein inhibitor, MS209, in combination with docetaxel in patients with advanced malignancies.

PURPOSE: The purpose of this study was to investigate the safety and tolerability of MS209, a potent inhibitor of P-glycoprotein, when given in combination with docetaxel and to determine whether MS209 affects docetaxel pharmacokinetics. EXPERIMENTAL DESIGN: Patients with advanced solid malignancies were eligible for this phase I trial. Docetaxel as 1-hour infusion was given alone during the first cycle. MS209 was introduced as of cycle 2 and given orally 30 minutes after docetaxel infusion. The dose escalation scheme followed a modified Fibonacci model with six steps (docetaxel, 60-100 mg/m2 and MS209, 300-1,200 mg per body). RESULTS: A total of 30 patients were treated at five dose levels. Dose-limiting toxicities were febrile neutropenia, infection, stomatitis, dysphagia, and fatigue. The maximum tolerated dose was reached at level 5 (docetaxel, 80-MS: 1,200). Pharmacokinetic analysis failed to show a strong pharmacokinetic interaction between the two compounds, but at the highest dose levels, there is a trend to an increase of docetaxel AUC when this agent is given in combination with MS209. CONCLUSION: MS209 can be given in combination with docetaxel, with limited effect on docetaxel toxicity or pharmacokinetics.