Several mutations in the melanocortin-4 receptor gene including a nonsense and a frameshift mutation associated with dominantly inherited obesity in humans

The melanocortin-4 receptor gene (MC4-R) has been implicated in weight regulation. Recently, two independent groups reported frameshift mutations associated with a dominant form of obesity (1, 2). We screened the coding region of the MC4-R in 306 extremely obese children and adolescents (mean body mass index: BMI 34.4 +/- 6.6 kg/m2), 25 healthy underweight students (mean BMI 17.1 +/- 0.8 kg/m2), 52 normal weight individuals (mean BMI 22.0 +/- 1.0 kg/m2), 51 inpatients with anorexia nervosa (AN, DSM IV criteria, mean BMI 14.3 +/- 1.5 kg/m2) and 27 patients with bulimia nervosa (BN, DSM IV criteria, mean BMI 21.7 +/- 5.8 kg/m2) by single strand conformation polymorphism analysis (SSCP). Several mutations were identified, including the frameshift mutation described (1). The mutations were as follows: a) The deletion of 4 bp (delta of CTCT at codon 211) results in a frameshift, thus rendering a truncated protein. This mutation has been assumed to be associated with dominantly-inherited morbid obesity in humans (1). Both the index patient (BMI 42.06 kg/m2, height 171 cm, age 19.6 years) and her mother (BMI 37.55 kg/m2, height 164 cm, age 42.5 years) were heterozygous for the deletion. b) A nonsense mutation at position 35 of the MC4-R was detected in two obese probands (BMI 31.29 kg/m2 and BMI 45.91 kg/m2). This mutation leads to a truncated protein that encompasses the N-terminal extracellular domain. Both carriers additionally showed (c) a missense mutation (Asp-37-Val). In both of these cases Tyr-35-Stop and Asp-37-Val were maternally transmitted, thus these variations form a haplotype. d) e) A male obese proband harbored two missense mutations (Ser-30-Phe, Gly-252-Ser). f)-i) Four different missense mutations (Pro-78-Leu, Thr-112-Met, Arg-165-Trp, Ile-317-Thr) were detected in four different male probands, respectively. All of these mutations (a to i) were found solely in extremely obese individuals whose BMIs were all above the 99th percentile. j) A silent mutation (C-579-T, Val-193-Val) was detected in a male underweight individual. k) A previously described polymorphism (Val-103-Ile; 3) was detected with similar frequencies in all different study groups. 1) We identified a novel polymorphism (Ile-251-Leu) with similar allele frequencies in all groups under study. In conclusion, our data indicate that mutations in the MC4-R are not uncommon. Whereas our data support the evidence for dominantly inherited obesity as revealed by the three obese probands with haplo-insufficiency, the functional significance of the missense mutations remains to be determined.     

Evaluation of brainstem function, using acoustic evoked potentials, in 26 patients harbouring a CSF shunt for non-tumoral aqueductal stenosis hydrocephalus

26 patients harbouring a CSF shunt for non-tumoral aqueductal stenosis hydrocephalus underwent Brainstem Acoustic Evoked Potentials (BAEPs) recording, to evaluate brainstem function. Only 6 patients presented with normal responses both at standard and at sensitized tests. In the remaining 19 patients, BAEPs were abnormal, bilaterally in 10 cases, monolaterally in 9. Four out of the 6 normal responses belonged to the group recognized of congenital origin. As refers to ventricular size BAEPs were abnormal in 62% of patients with normal ventricle and in 92% of patients with enlarged ventricles. The most significant BAEPs abnormalities were found in patients with maximal ventricular dilation. It appears that BAEPs abnormalities are to the ascribed to both primary and secondary brainstem dysfunction: no reliable criterion to differentiate between these two possibilities is evident. In the individual patient, serial BAEPs recording may contribute to recognize the early phase of supratentorial hypertension due to shunt dysfunction.     

Basal cell carcinoma surrounded by lentigo maligna

A case of nodular basal cell carcinoma occurring within a lentigo maligna is reported. This case illustrates the fact that not all nodules appearing within a lentigo maligna are melanoma.     

Generation of a functional and durable vascular niche by the adenoviral E4ORF1 gene

Vascular cells contribute to organogenesis and tumorigenesis by producing unknown factors. Primary endothelial cells (PECs) provide an instructive platform for identifying factors that support stem cell and tumor homeostasis. However, long-term maintenance of PECs requires stimulation with cytokines and serum, resulting in loss of their angiogenic properties. To circumvent this hurdle, we have discovered that the adenoviral E4ORF1 gene product maintains long-term survival and facilitates organ-specific purification of PECs, while preserving their vascular repertoire for months, in serum/cytokine-free cultures. Lentiviral introduction of E4ORF1 into human PECs (E4ORF1⁺ ECs) increased the long-term survival of these cells in serum/cytokine-free conditions, while preserving their in vivo angiogenic potential for tubulogenesis and sprouting. Although E4ORF1, in the absence of mitogenic signals, does not induce proliferation of ECs, stimulation with VEGF-A and/or FGF-2 induced expansion of E4ORF1⁺ ECs in a contact-inhibited manner. Indeed, VEGF-A-induced phospho MAPK activation of E4ORF1⁺ ECs is comparable with that of naive PECs, suggesting that the VEGF receptors remain functional upon E4ORF1 introduction. E4ORF1⁺ ECs inoculated in implanted Matrigel plugs formed functional, patent, humanized microvessels that connected to the murine circulation. E4ORF1⁺ ECs also incorporated into neo-vessels of human tumor xenotransplants and supported serum/cytokine-free expansion of leukemic and embryonal carcinoma cells. E4ORF1 augments survival of PECs in part by maintaining FGF-2/FGF-R1 signaling and through tonic Ser-473 phosphorylation of Akt, thereby activating the mTOR and NF-κB pathways. Therefore, E4ORF1⁺ ECs establish an Akt-dependent durable vascular niche not only for expanding stem and tumor cells but also for interrogating the roles of vascular cells in regulating organ-specific vascularization and tumor neo-angiogenesis.     

A Case of Acute Cardiomyopathy and Pericarditis Associated with Methylphenidate

Methylphenidate is a potent central nervous system stimulant that exerts its effects by increasing synaptic levels of dopamine and norepinephrine. It has become key to treating attention deficit-hyperactivity disorder (ADHD) in children and adolescents. As the use of stimulant medications has ballooned in the past decade, so too has awareness of the cardiovascular complications of these drugs. Effects on heart rate and blood pressure as well as tachyarrhythmias have been well described. However, acute cardiomyopathy and pericarditis secondary to methylphenidate use has been rarely reported. We report the case of a 17-year-old male who developed chest pain, elevated cardiac biomarkers, and acute left ventricular dysfunction following a single dose of methylphenidate. The risk of cardiomyopathy in the setting of methylphenidate treatment should prompt further study on the safety of this drug, and lead to ways of identifying those at risk of developing these complications.     

Role of natural killer cells in innate protection against lethal ebola virus infection

Ebola virus is a highly lethal human pathogen and is rapidly driving many wild primate populations toward extinction. Several lines of evidence suggest that innate, nonspecific host factors are potentially critical for survival after Ebola virus infection. Here, we show that nonreplicating Ebola virus-like particles (VLPs), containing the glycoprotein (GP) and matrix protein virus protein (VP)40, administered 1-3 d before Ebola virus infection rapidly induced protective immunity. VLP injection enhanced the numbers of natural killer (NK) cells in lymphoid tissues. In contrast to live Ebola virus, VLP treatment of NK cells enhanced cytokine secretion and cytolytic activity against NK-sensitive targets. Unlike wild-type mice, treatment of NK-deficient or -depleted mice with VLPs had no protective effect against Ebola virus infection and NK cells treated with VLPs protected against Ebola virus infection when adoptively transferred to naive mice. The mechanism of NK cell-mediated protection clearly depended on perforin, but not interferon-gamma secretion. Particles containing only VP40 were sufficient to induce NK cell responses and provide protection from infection in the absence of the viral GP. These findings revealed a decisive role for NK cells during lethal Ebola virus infection. This work should open new doors for better understanding of Ebola virus pathogenesis and direct the development of immunotherapeutics, which target the innate immune system, for treatment of Ebola virus infection.