A unique melanocortin-4-receptor signaling profile for obesity-associated constitutively active variants.

The melanocortin-4 receptor (MC4R) plays a critical role in regulating energy homeostasis. Studies on obesogenic human MC4R (hMC4R) variants have not yet revealed how hMC4R maintains body weight. Here, we identified a signaling profile for obesogenic constitutively active H76R and L250Q hMC4R variants transfected in HEK293 cells that included constitutive activity for adenylyl cyclase (AC), cyclic adenosine monophosphate (cAMP) response element (CRE)-driven transcription, and calcium mobilization but not phosphorylated extracellular signal-regulated kinase 1/2 (pERK1/2) activity. Importantly, the signaling profile included impaired α-melanocyte-stimulating hormone-induced CRE-driven transcription but not impaired α-melanocyte-stimulating hormone-induced AC, calcium, or pERK1/2. This profile was not observed for transfected H158R, a constitutively active hMC4R variant associated with overweight but not obesity. We concluded that there is potential for α-melanocyte-stimulating hormone-induced CRE-driven transcription in HEK293 cells transfected with obesogenic hMC4R variants to be the key predictive tool for determining whether they exhibit loss of function. Furthermore, in vivo, α-melanocyte-stimulating hormone-induced hMC4R CRE-driven transcription may be key for maintaining body weight.

Mycoplasma hominis Lumbar Wound Infection After Posterior Decompression and Instrumented Fusion: A Case Report.

CASE: A 63-year-old man underwent L2-S1 decompression and fusion for spinal stenosis. He developed urinary retention postoperatively requiring catheterization. He developed fever, purulence, and foot-drop 8 days postoperatively and underwent debridement with implant retention. Cultures yielded Mycoplasma hominis after 10 days. He received 4 weeks of doxycycline. Four years postoperatively, he had no recurrence of infection and was able to ambulate despite a persistent foot-drop. CONCLUSION: Mycoplasma hominis is a urogenital commensal rarely implicated in musculoskeletal infections. A high index of suspicion is required in spinal surgery patients who develop fever and purulence and have initial negative cultures and poor response to empirical antibiotics.

A new species of Asian gracile skink (Scincidae: Lygosominae: emSubdoluseps/em) from the rain-shadow belts of Nilgiri hills, Western Ghats, India.

We describe a new species of Asian gracile skink from the dry leeward slopes of the Nilgiri hills, Tamil Nadu state, India which forms a part of the eastern, rain shadow escarpment of the Western Ghats in peninsular India. The new species, Subdoluseps nilgiriensis sp. nov., is characterized by: slender, small-sized body (47-67 mm); sandy brown above, with each scale tipped with black; a thick black lateral band from snout to tail; a distinct white labial streak; dirty white venter, with throat having mild black striations; 28-29 midbody scale rows; 71-74 mid ventral scales; 66-69 paravertebral scales. The new species is described based on external morphological characters, genetic data and geographical isolation. Based on two mitochondrial DNA genes, we show that the new species shares a sister relationship with Subdoluseps pruthi (Sharma, 1977) which is found in parts of the Eastern Ghats in peninsular India. The discovery of this new population raises two novel scenarios. Firstly, it renders the genus Subdoluseps evolutionarily polyphyletic with respect to the Indian species included in this genus. Secondly, it falsifies the notion that S. pruthi group skinks are restricted to the Eastern Ghats. Our results further indicate that the dry zone of peninsular India has unrealized skink diversity that needs to be further explored.

Quantitative high-throughput assay to measure MC4R-induced intracellular calcium.

The melanocortin-4 receptor (MC4R), a critical G-protein-coupled receptor (GPCR) regulating energy homeostasis, activates multiple signalling pathways, including mobilisation of intracellular calcium ([Ca2+]i). However, very little is known about the physiological significance of MC4R-induced [Ca2+]i since few studies measure MC4R-induced [Ca2+]i. High-throughput, read-out assays for [Ca2+]i have proven unreliable for overexpressed GPCRs like MC4R, which exhibit low sensitivity mobilising [Ca2+]i. Therefore, we developed, optimised, and validated a robust quantitative high-throughput assay using Fura-2 ratio-metric calcium dye and HEK293 cells stably transfected with MC4R. The quantitation enables direct comparisons between assays and even between different research laboratories. Assay conditions were optimised step-by-step to eliminate interference from stretch-activated receptor increases in [Ca2+]i and to maximise ligand-activated MC4R-induced [Ca2+]i. Calcium imaging was performed using a PheraStar FS multi-well plate reader. Probenecid, included in the buffers to prevent extrusion of Fura-2 dye from cells, was found to interfere with the EGTA-chelation of calcium, required to determine Rmin for quantitation of [Ca2+]i. Therefore, we developed a method to determine Rmin in specific wells without probenecid, which was run in parallel with each assay. The validation of the assay was shown by reproducible α-melanocyte-stimulating hormone (α-MSH) concentration-dependent activation of the stably expressed human MC4R (hMC4R) and mouse MC4R (mMC4R), inducing increases in [Ca2+]i, for three independent experiments. This robust, reproducible, high-throughput assay that quantitatively measures MC4R-induced mobilisation of [Ca2+]i in vitro has potential to advance the development of therapeutic drugs and understanding of MC4R signalling associated with human obesity.

Cryptococcosis mimicking lung carcinoma with brain metastases in an immunocompetent patient.

Cryptococcosis is a fungal infection caused by Cryptococcus spp. that enters the body via inhalation. This ubiquitous yeast has gained notoriety as an opportunistic pathogen in the immunosuppressed population. The authors report a case of a previously-well adult male presented with left-sided weakness. Imaging demonstrated a pulmonary mass and 2 contrast-enhancing intracranial lesions-all features suggestive of a primary lung carcinoma with brain metastases. However, further investigations confirmed disseminated cryptococcosis, without evidence of malignancy. The patient was successfully treated with a course of antifungals. To the authors' knowledge, this is the first reported case of dissemintated cryptococcosis in an immunocompetent adult male, simulating as primary lung carcinoma with brain metastases.

Klebsiella ozaenae Bacteremia in a Kidney Transplant Recipient.

Infections remain a dreadful complication after solid organ transplantation. Almost all microorganisms could cause this complication, including unusual ones. We report a 73-year-old patient, with a history of kidney transplant for 38 years on minimum immunosuppression, who presented with high-grade fever and gastrointestinal symptoms. Klebsiella ozaenae was isolated from blood cultures. She had a prompt response to antibiotics and recovered completely in a short period. Subsequent evaluation of her nasal cavity and sinuses did not show any abnormalities. Klebsiella ozaenae is primarily a colonizer of the oral and nasopharyngeal mucosa, which does not usually cause severe infections. Only 12 cases of Klebsiella ozaenae bacteremia have been reported, none of them in the context of solid organ transplant recipient.

Parallel Iteration to the Radiative Transport in Inhomogeneous Media with Bootstrapping.

This paper presents a fast parallel method to solve the radiative transport equation in inhomogeneous participating media. We apply a novel approximation scheme to find a good initial guess for both the direct and scattered components. Then, the initial approximation is used to bootstrap an iterative multiple scattering solver, i.e., we let the iteration concentrate just on the residual problem. This kind of bootstrapping makes the volumetric source approximation more uniform, thus it helps to reduce the discretization artifacts and improves the efficiency of the parallel implementation. The iterative refinement is executed on a face-centered cubic grid. The implementation is based on CUDA and runs on the GPU. For large volumes that do not fit into the GPU memory, we also consider the implementation on a GPU cluster, where the volume is decomposed to blocks according to the available GPU nodes. We show how the communication bottleneck can be avoided in the cluster implementation by not exchanging the boundary conditions in every iteration step. In addition to light photons, we also discuss the generalization of the method to γ-photons that are relevant in medical simulation.