Cutaneous Mucormycosis in an Immunocompetent Child following a Minor Skin Trauma.

Cutaneous mucormycosis is a rare infection by the Zygomycetes class of fungi, which carries significant morbidity and mortality. While typically associated in patients with underlying immunocompromise (especially in the current era of COVID-19), it may also be seen in immunocompetent patients. We report a case of a healthy 4-year-old girl with acute right leg cellulitis and abscess formation, who required surgical debridement following poor response to antibiotic therapy and initial incision and drainage. Tissue histopathology returned cutaneous zygomycosis despite negative tissue cultures. At four-week follow-up, her wound was healed well. Clinicians should maintain a high degree of clinical suspicion for cutaneous mucormycosis given its potential for rapidly progressive and disseminated disease. Currently, the mainstay of diagnostic investigations is tissue histopathology, with a growing role for tissue fungal PCR. Treatment involves multidisciplinary management between surgeons and Infectious Diseases team to guide the role for surgical debridement and antifungal therapy.

Tunneled biopsy is an underutilised, simple, safe and efficient method for tissue acquisition from subepithelial tumours.

BACKGROUND: Tissue acquisition from subepithelial lesions is often attempted by endoscopic ultrasound (EUS)-sampling as conventional endoscopic biopsy usually fails to reach deeper layers of the gastrointestinal wall. AIM: To investigate the utilisation, safety and diagnostic yield of an intensified "bite-on-bite" tunnel biopsy technique. METHODS: In this retrospective cohort study, all patients presenting with subepithelial masses in the upper gastrointestinal tract from March 2013 to July 2019 were included. Data were analysed for size and location of the subepithelial mass, use of intensified tunnel biopsy protocol (more than 10 double bite-on-bite biopsies) or superficial conventional biopsies, histology and imaging results, occurrence of readmission and adverse events after endoscopy. RESULTS: Two hundred and twenty-nine patients with subepithelial lesions were included. Superficial conventional biopsies were taken in 117 patients and were diagnostic only in one lipoma (0.9 %). Tunnel biopsies taken in 112/229 (48.9%) patients were significantly more likely to provide histological diagnosis (53.6%; P < 0.001). For lesions ≥ 10mm the diagnostic yield of tunnel biopsies further increased to 41/67 (61.2%). No immediate or delayed complications were reported. Only 8 of the 51 endoscopists (15.7%) regularly attempted tunnel biopsies. CONCLUSION: Tunnel biopsy is a simple, safe and efficient but underutilised diagnostic modality for tissue acquisition in subepithelial masses. It should be routinely attempted at the initial endoscopy.

Lump at the back of my tongue. The lingual thyroid-A case report and narrative review of literature.

Although the ectopic thyroid in adults is rarely symptomatic, biochemistry and imaging workup are essential. Treatment modality of choice is dependent on patient factors, institution factors and surgeon factors. The mainstay treatment involves hormone suppression treatment with exogenous thyroid hormone. If medical management is unsuccessful, surgical excision requires an experienced team including an anaesthetist and otolaryngologist. Anaesthetic considerations are important because intubation may be a potentially difficult procedure secondary to potential serious obstruction of the upper airway. We present a case report and narrative review of the literature regarding lingual thyroid workup and management.

Divergent off-target effects of RSK N-terminal and C-terminal kinase inhibitors in cardiac myocytes.

P90 ribosomal S6 kinases (RSK) are ubiquitously expressed and regulate responses to neurohumoral stimulation. To study the role of RSK signalling on cardiac myocyte function and protein phosphorylation, pharmacological RSK inhibitors were tested. Here, the ATP competitive N-terminal kinase domain-targeting compounds D1870 and SL0101 and the allosteric C-terminal kinase domain-targeting FMK were evaluated regarding their ability to modulate cardiac myocyte protein phosphorylation. Exposure to D1870 and SL0101 significantly enhanced phospholamban (PLN) Ser16 and cardiac troponin I (cTnI) Ser22/23 phosphorylation in response to D1870 and SL0101 upon exposure to phenylephrine (PE) that activates RSK. In contrast, FMK pretreatment significantly reduced phosphorylation of both proteins in response to PE. D1870-mediated enhancement of PLN Ser16 phosphorylation was also observed after exposure to isoprenaline or noradrenaline (NA) stimuli that do not activate RSK. Inhibition of ß-adrenoceptors by atenolol or cAMP-dependent protein kinase (PKA) by H89 prevented the D1870-mediated increase in PLN phosphorylation, suggesting that PKA is the kinase responsible for the observed phosphorylation. Assessment of changes in cAMP formation by FRET measurements revealed increased cAMP formation in vicinity to PLN after exposure to D1870 and SL0101. D1870 inhibited phosphodiesterase activity similarly as established PDE inhibitors rolipram or 3-isobutyl-1-methylxanthine. Assessment of catecholamine-mediated force development in rat ventricular muscle strips revealed significantly reduced EC50 for NA after D1870 pretreatment (DMSO/NA: 2.33 µmol/L vs. D1870/NA: 1.30 µmol/L). The data reveal enhanced cardiac protein phosphorylation by D1870 and SL0101 that was not detectable in response to FMK. This disparate effect might be attributed to off-target inhibition of PDEs with impact on muscle function as demonstrated for D1870.

Cardiomyocyte Membrane Structure and cAMP Compartmentation Produce Anatomical Variation in ß2AR-cAMP Responsiveness in Murine Hearts.

Cardiomyocytes from the apex but not the base of the heart increase their contractility in response to ß2-adrenoceptor (ß2AR) stimulation, which may underlie the development of Takotsubo cardiomyopathy. However, both cell types produce comparable cytosolic amounts of the second messenger cAMP. We investigated this discrepancy using nanoscale imaging techniques and found that, structurally, basal cardiomyocytes have more organized membranes (higher T-tubular and caveolar densities). Local membrane microdomain responses measured in isolated basal cardiomyocytes or in whole hearts revealed significantly smaller and more short-lived ß2AR/cAMP signals. Inhibition of PDE4, caveolar disruption by removing cholesterol or genetic deletion of Cav3 eliminated differences in local cAMP production and equilibrated the contractile response to ß2AR. We conclude that basal cells possess tighter control of cAMP because of a higher degree of signaling microdomain organization. This provides varying levels of nanostructural control for cAMP-mediated functional effects that orchestrate macroscopic, regional physiological differences within the heart.

Atropine augments cardiac contractility by inhibiting cAMP-specific phosphodiesterase type 4.

Atropine is a clinically relevant anticholinergic drug, which blocks inhibitory effects of the parasympathetic neurotransmitter acetylcholine on heart rate leading to tachycardia. However, many cardiac effects of atropine cannot be adequately explained solely by its antagonism at muscarinic receptors. In isolated mouse ventricular cardiomyocytes expressing a Förster resonance energy transfer (FRET)-based cAMP biosensor, we confirmed that atropine inhibited acetylcholine-induced decreases in cAMP. Unexpectedly, even in the absence of acetylcholine, after G-protein inactivation with pertussis toxin or in myocytes from M2- or M1/3-muscarinic receptor knockout mice, atropine increased cAMP levels that were pre-elevated with the ß-adrenergic agonist isoproterenol. Using the FRET approach and in vitro phosphodiesterase (PDE) activity assays, we show that atropine acts as an allosteric PDE type 4 (PDE4) inhibitor. In human atrial myocardium and in both intact wildtype and M2 or M1/3-receptor knockout mouse Langendorff hearts, atropine led to increased contractility and heart rates, respectively. In vivo, the atropine-dependent prolongation of heart rate increase was blunted in PDE4D but not in wildtype or PDE4B knockout mice. We propose that inhibition of PDE4 by atropine accounts, at least in part, for the induction of tachycardia and the arrhythmogenic potency of this drug.

Incidence and risk factors for non-alcoholic fatty liver disease: A 7-year follow-up study among urban, adult Sri Lankans.

BACKGROUND: This study investigated incidence and risk factors for NAFLD among an adult cohort with 7-year follow-up. METHODS: The study population (age-stratified random sampling, Ragama MOH area) was screened initially in 2007 (aged 35-64 years) and re-evaluated in 2014 (aged 42-71 years). On both occasions assessed by structured interview, anthropometric measurements, liver ultrasound, biochemical and serological tests. NAFLD was diagnosed on ultrasound criteria, safe alcohol consumption and absence of hepatitis B/C markers. Non-NAFLD controls did not have any ultrasound criteria for NAFLD. An updated case-control genetic association study for 10 selected genetic variants and NAFLD was also performed. RESULTS: Out of 2985 of the original cohort, 2148 (72.0%) attended follow-up (1238 [57.6%] women; mean-age 59.2 [SD-7.6] years) in 2014, when 1320 (61.5%) were deemed NAFLD subjects. Out of 778 who initially did not have NAFLD and were not heavy drinkers throughout follow-up, 338 (43.4%) (221 [65.4%] women, mean-age 57.8 [SD-8.0] years) had developed NAFLD after 7-years (annual incidence-6.2%). Central obesity (OR=3.82 [95%-CI 2.09-6.99]), waist increase >5% (OR=2.46 [95%-CI 1.20-5.05]) overweight (OR=3.26 [95%-CI 1.90-5.60]), weight gain 5%-10% (OR=5.70 [95%-CI 2.61-12.47]), weight gain >10% (OR=16.94 [95%-CI 6.88-41.73]), raised plasma triglycerides (OR=1.96 [95%-CI 1.16-3.29]) and diabetes (OR=2.14 [95%-CI 1.13-4.06]), independently predicted the development of incident NAFLD in multivariate analysis. The updated genetic association study (1362-cases, 392-controls) showed replicated association (P=.045, 1-tailed) with NAFLD at a candidate locus: PNPLA3 (rs738409). CONCLUSIONS: In this community cohort study, the annual incidence of NAFLD was 6.2%. Incident NAFLD was associated with general and central obesity, raised triglycerides and diabetes, and showed a tendency of association with PNPLA3 gene polymorphisms.

Regulation of matrix metalloproteinases (MMPs) expression and secretion in MDA-MB-231 breast cancer cells by LIM and SH3 protein 1 (LASP1).

The process of tumor invasion requires degradation of extracellular matrix by proteolytic enzymes. Cancer cells form protrusive invadopodia, which produce and release matrix metalloproteinases (MMPs) to degrade the basement membrane thereby enabling metastasis. We investigated the effect of LASP1, a newly identified protein in invadopodia, on expression, secretion and activation of MMPs in invasive breast tumor cell lines.By analyzing microarray data of in-house generated control and LASP1-depleted MDA-MB-231 breast cancer cells, we observed downregulation of MMP1, -3 and -9 upon LASP1 depletion. This was confirmed by Western blot analysis. Conversely, rescue experiments restored in part MMP expression and secretion. The regulatory effect of LASP1 on MMP expression was also observed in BT-20 breast cancer cells as well as in prostate and bladder cancer cell lines.In line with bioinformatic FunRich analysis of our data, which mapped a high regulation of transcription factors by LASP1, public microarray data analysis detected a correlation between high LASP1 expression and enhanced c-Fos levels, a protein that is part of the transcription factor AP-1 and known to regulate MMP expression. Compatibly, in luciferase reporter assays, AP-1 showed a decreased transcriptional activity after LASP1 knockdown.Zymography assays and Western blot analysis revealed an additional promotion of MMP secretion into the extracellular matrix by LASP1, thus, most likely, altering the microenvironment during cancer progression.The newly identified role of LASP1 in regulating matrix degradation by affecting MMP transcription and secretion elucidated the migratory potential of LASP1 overexpressing aggressive tumor cells in earlier studies.

In vivo model with targeted cAMP biosensor reveals changes in receptor-microdomain communication in cardiac disease.

3',5'-cyclic adenosine monophosphate (cAMP) is an ubiquitous second messenger that regulates physiological functions by acting in distinct subcellular microdomains. Although several targeted cAMP biosensors are developed and used in single cells, it is unclear whether such biosensors can be successfully applied in vivo, especially in the context of disease. Here, we describe a transgenic mouse model expressing a targeted cAMP sensor and analyse microdomain-specific second messenger dynamics in the vicinity of the sarcoplasmic/endoplasmic reticulum calcium ATPase (SERCA). We demonstrate the biocompatibility of this targeted sensor and its potential for real-time monitoring of compartmentalized cAMP signalling in adult cardiomyocytes isolated from a healthy mouse heart and from an in vivo cardiac disease model. In particular, we uncover the existence of a phosphodiesterase-dependent receptor-microdomain communication, which is affected in hypertrophy, resulting in reduced ß-adrenergic receptor-cAMP signalling to SERCA.

Microdomain switch of cGMP-regulated phosphodiesterases leads to ANP-induced augmentation of ß-adrenoceptor-stimulated contractility in early cardiac hypertrophy.

RATIONALE: Cyclic nucleotides are second messengers that regulate cardiomyocyte function through compartmentalized signaling in discrete subcellular microdomains. However, the role of different microdomains and their changes in cardiac disease are not well understood. OBJECTIVE: To directly visualize alterations in ß-adrenergic receptor-associated cAMP and cGMP microdomain signaling in early cardiac disease. METHODS AND RESULTS: Unexpectedly, measurements of cell shortening revealed augmented ß-adrenergic receptor-stimulated cardiomyocyte contractility by atrial natriuretic peptide/cGMP signaling in early cardiac hypertrophy after transverse aortic constriction, which was in sharp contrast to well-documented ß-adrenergic and natriuretic peptide signaling desensitization during chronic disease. Real-time cAMP analysis in ß1- and ß2-adrenergic receptor-associated membrane microdomains using a novel membrane-targeted Förster resonance energy transfer-based biosensor transgenically expressed in mice revealed that this unexpected atrial natriuretic peptide effect is brought about by spatial redistribution of cGMP-sensitive phosphodiesterases 2 and 3 between both receptor compartments. Functionally, this led to a significant shift in cGMP/cAMP cross-talk and, in particular, to cGMP-driven augmentation of contractility in vitro and in vivo. CONCLUSIONS: Redistribution of cGMP-regulated phosphodiesterases and functional reorganization of receptor-associated microdomains occurs in early cardiac hypertrophy, affects cGMP-mediated contractility, and might represent a previously not recognized therapeutically relevant compensatory mechanism to sustain normal heart function.

Frequency, pattern and short-term outcome of chronic renal dysfunction in patients with cirrhosis: a prospective study using HRS and ADQI-IAC criteria.

BACKGROUND: Diagnostic criteria of hepatorenal syndrome type 2 (HRS2) fail to detect milder degrees of chronic renal dysfunction (CRD) in cirrhosis and exclude patients with pre-existing kidney disease. Definitions addressing this have been proposed by Working Party of the Acute Dialysis Quality Initiative and International Ascites Club (ADQI-IAC). AIMS: We studied the frequency, pattern and short-term outcome of CRD in patients with cirrhosis, using both HRS2 and ADQI-IAC criteria. PATIENTS AND METHODS: Consecutive patients with cirrhosis and stable serum creatinine for 3 months or more attending outpatient clinics in Colombo North Teaching Hospital (Ragama, Sri Lanka) were prospectively recruited and followed up. RESULTS: Of 277 patients with cirrhosis and stable serum creatinine, 23 (8.3%) fulfilled criteria for HRS2, and 65/277 (23.5%) had estimated glomerular filtration rate (eGFR) less than 60 ml/min/1.73 m [ADQI-IAC definition of chronic kidney disease (CKD)]. This included the 23 patients with HRS2 and an additional 42/65 (64.6%) who did not fulfil diagnostic criteria for HRS2 (non-HRS2 CKD). In all, 58/277 (20.9%) died during follow-up [mean 9.8 months (SD 4.5)]. This included 12/23 (52.2%) with HRS2 and 14/42 (33.3%) with non-HRS2 CKD. On the basis of multiple regression model, Child-Turcotte-Pugh class and CRD were significantly associated with death. After correcting for Child-Turcotte-Pugh class, both HRS2 (odds ratio 4.56, 95% confidence interval 1.79-11.53) and non-HRS2 CKD (odds ratio 2.19, 95% confidence interval 1.02-4.68) were independently associated with death. CONCLUSION: Compared with HRS2 criteria, eGFR less than 60 ml/min/1.73 m detected almost twice the number of cirrhotics with CRD. Patients with eGFR less than 60 ml/min/1.73 m who did not fulfil criteria for HRS2 also had significant short-term mortality. ADQI-IAC criteria thus appear to be a more useful definition of CRD in cirrhotics.

Transgenic mice for real-time visualization of cGMP in intact adult cardiomyocytes.

RATIONALE: 3',5'-Cyclic guanosine monophosphate (cGMP) is an important second messenger that regulates cardiac contractility and protects the heart from hypertrophy. However, because of the lack of real-time imaging techniques, specific subcellular mechanisms and spatiotemporal dynamics of cGMP in adult cardiomyocytes are not well understood. OBJECTIVE: Our aim was to generate and characterize a novel cGMP sensor model to measure cGMP with nanomolar sensitivity in adult cardiomyocytes. METHODS AND RESULTS: We generated transgenic mice with cardiomyocyte-specific expression of the highly sensitive cytosolic Förster resonance energy transfer-based cGMP biosensor red cGES-DE5 and performed the first Förster resonance energy transfer measurements of cGMP in intact adult mouse ventricular myocytes. We found very low (≈10 nmol/L) basal cytosolic cGMP levels, which can be markedly increased by natriuretic peptides (C-type natriuretic peptide >> atrial natriuretic peptide) and, to a much smaller extent, by the direct stimulation of soluble guanylyl cyclase. Constitutive activity of this cyclase contributes to basal cGMP production, which is balanced by the activity of clinically established phosphodiesterase (PDE) families. The PDE3 inhibitor, cilostamide, showed especially strong cGMP responses. In a mild model of cardiac hypertrophy after transverse aortic constriction, PDE3 effects were not affected, whereas the contribution of PDE5 was increased. In addition, after natriuretic peptide stimulation, PDE3 was also involved in cGMP/cAMP crosstalk. CONCLUSIONS: The new sensor model allows visualization of real-time cGMP dynamics and pharmacology in intact adult cardiomyocytes. Förster resonance energy transfer imaging suggests the importance of well-established and potentially novel PDE-dependent mechanisms that regulate cGMP under physiological and pathophysiological conditions.

Classic polyarteritis nodosa associated with hepatitis C virus infection: a case report.

INTRODUCTION: Hepatitis C virus has been under-recognized as an etiologic factor for polyarteritis nodosa and the presence of hepatitis C antigenemia in patients with polyarteritis nodosa has been reported as insignificant. In the literature hepatitis C virus-associated polyarteritis nodosa is a rare and controversial entity. CASE PRESENTATION: A 34-year-old Sri Lankan Tamil man presented to our facility with a two-week history of slow-resolving pneumonia of the right mid and lower zones. On physical examination he had panniculitic type tender skin nodules with background livedo reticularis. A skin biopsy was suggestive of a small and medium vessel vasculitis compatible with polyarteritis nodosa. He was tested positive for hepatitis C antibodies. A serum cryoglobulin test was negative but perinuclear antineutrophilic cytoplasmic antibody test was positive. Serum complement levels were reduced. He was diagnosed as having classic polyarteritis nodosa associated with hepatitis C infection. He later developed left-sided radiculopathy involving both upper and lower limbs and an ischemic cardiac event. His hepatitis C infection was managed with polyethylene glycol-interferon 2α combined with oral ribavirin. Simultaneously, his classic polyarteritis nodosa was treated with prednisolone and cyclophosphamide. He made a good recovery. CONCLUSIONS: Hepatitis C virus infection is capable of inducing a fulminant form of vasculitis in the form of polyarteritis nodosa. It may be easily confused early in its course with mixed cryoglobulinemia, which is commonly known to be associated with hepatitis C virus. Awareness of hepatitis C virus-related polyarteritis nodosa helps in diagnosing the condition early so combined immunosuppressive and antiviral treatment can be started as soon as possible.

FRET microscopy for real-time monitoring of signaling events in live cells using unimolecular biosensors.

Förster resonance energy transfer (FRET) microscopy continues to gain increasing interest as a technique for real-time monitoring of biochemical and signaling events in live cells and tissues. Compared to classical biochemical methods, this novel technology is characterized by high temporal and spatial resolution. FRET experiments use various genetically-encoded biosensors which can be expressed and imaged over time in situ or in vivo. Typical biosensors can either report protein-protein interactions by measuring FRET between a fluorophore-tagged pair of proteins or conformational changes in a single protein which harbors donor and acceptor fluorophores interconnected with a binding moiety for a molecule of interest. Bimolecular biosensors for protein-protein interactions include, for example, constructs designed to monitor G-protein activation in cells, while the unimolecular sensors measuring conformational changes are widely used to image second messengers such as calcium, cAMP, inositol phosphates and cGMP. Here we describe how to build a customized epifluorescence FRET imaging system from single commercially available components and how to control the whole setup using the Micro-Manager freeware. This simple but powerful instrument is designed for routine or more sophisticated FRET measurements in live cells. Acquired images are processed using self-written plug-ins to visualize changes in FRET ratio in real-time during any experiments before being stored in a graphics format compatible with the build-in ImageJ freeware used for subsequent data analysis. This low-cost system is characterized by high flexibility and can be successfully used to monitor various biochemical events and signaling molecules by a plethora of available FRET biosensors in live cells and tissues. As an example, we demonstrate how to use this imaging system to perform real-time monitoring of cAMP in live 293A cells upon stimulation with a ß-adrenergic receptor agonist and blocker.