Incidence of Pediatric Cancers in French Guiana: How Does It Compare to Global Estimates?

French Guiana is a French territory in South America. The exposome of persons living there is quite different from that in mainland France and the ethnic make-up of the population is also quite different. Poverty is also widespread with difficulties in accessing care magnified by the low medical-professional density. In this singular context, we aimed to measure the incidence of pediatric cancers and to compare it with other continents. We used French Guiana's certified cancer registry to study this between 2003 and 2017. Incidences were standardized using the world population with three strata: 0-4 years, 5-9 years, and 10-14 years. There were 164 solid tumors or hematologic malignancies diagnosed in children under the age of 15 (92 in boys and 72 in girls). Over the study period, the standardized incidence rate was 14.1 per 100,000 among children aged under 15 years. There was no significant trend during the study period. The three most common causes of cancer were leukemias-mostly lymphoblastic-CNS tumors, and sarcoma. The standardized incidence of pediatric cancers in French Guiana was similar to those in Western Europe and North America. As others have discovered, we found that males tended to be more likely to develop cancer, notably leukemia, CNS tumors, sarcoma, and retinoblastoma. As elsewhere, the predominant cancer types changed with age. Our initial assumption was that given the singular context of French Guiana, there may have been differences in pediatric cancer incidences. Here we showed that overall, contrary to our assumption and to trends in tropical countries, the incidence of pediatric cancers was in a range between Western Europe and North America with some apparent but non-significant differences in the main types of cancers observed in global statistics. Quality cancer registry data in this tropical region confirm the suspicion that lower incidences in tropical low- and middle-income countries are likely to result from incomplete diagnosis and data collection.

Early Diagnosis in Cerebellar Ataxia, Neuropathy, Vestibular Areflexia Syndrome (CANVAS) by Focusing on Major Clinical Clues: Beyond Ataxia and Vestibular Impairment.

CANVAS, a rare disorder responsible for late-onset ataxia of autosomal recessive inheritance, can be misdiagnosed. We investigated a series of eight patients with sensory neuropathy and/or an unexplained cough, who appeared to suffer from CANVAS, and we emphasized the clinical clues for early diagnosis. Investigations included clinical and routine laboratory analyses, skin biopsy, nerve biopsy and molecular genetics. The eight patients had clinical and/or laboratory evidence of sensory neuronopathy. All but one had neuropathic pain that had started in an asymmetric fashion in two patients. A chronic cough was a prominent feature in our eight patients and had started years before neuropathic symptoms in all but one. The course of the disease was slow, and ataxia remained mild in all. Five patients were initially thought to have immune-mediated sensory neuronopathy and received immunotherapy. Skin biopsies showed a near complete and non-length-dependent loss of intraepidermal nerve fibers. Moreover, nerve biopsy findings suggested a prominent involvement of small myelinated and unmyelinated fibers. The burden of CANVAS extends far beyond cerebellar ataxia and vestibular manifestations. Indeed, our study shows that a chronic cough and neuropathic pain may represent a major source of impairment in these patients and should not be overlooked to allow an early diagnosis and prevent unnecessary immunotherapy.

Widening of myelin lamellae in polyneuropathy with immunoglobulin-M monoclonal gammopathy, without activity against myelin-associated glycoprotein, responsive to treatment.

We report the case of a patient with a very severe predominantly demyelinating sensorimotor polyneuropathy (with axonal loss) that had developed over several months, along with an immunoglobulin-M monoclonal gammopathy without anti-myelin associated glycoprotein antibodies (or other antibodies against myelin). Widening of myelin lamellae were frequently observed by electron microscopic examination of a nerve biopsy: immunoglobulin-M targeting an unknown myelin antigen appears to be responsible for the nerve lesions similar to those observed in anti-myelin associated glycoprotein polyneuropathy. Usually, if in anti-myelin associated glycoprotein neuropathy the response to immunotherapies is not optimal, in this case the combination of plasma exchanges and rituximab was effective, suggesting an autoimmune origin.

Are Miller Fisher syndrome and CANDA due to a paranodopathy?

OBJECTIVE: To study the pathological characteristics of acute and chronic ataxic peripheral neuropathy at the level of the node of Ranvier. STUDY DESIGN AND SETTING: We performed the pathological study (nerve biopsy of a sural nerve) of two patients, one with an acute form of ataxic peripheral neuropathy called 'Miller Fisher syndrome' (MFS), the other one with a chronic form called 'chronic ataxic neuropathies with disialosyl antibodies' (CANDA). RESULTS: A dysimmune process involving peripheral nerves commences in myelin, at the internodal area or/and in the paranodal and nodal regions. Our electron microscopic observations suggest that both patients present lesions in favor of a paranodopathy. CONCLUSION: Many of the immune-mediated peripheral neuropathies are now classified as nodoparanodopathies. This subtype of auto-immune neuropathy may present various clinical phenotypes such as 'Acute Motor Axonal Neuropathy' (AMAN), 'Acute Motor and Sensory Neuropathy' (AMSAN) or 'chronic inflammatory demyelinating polyradiculoneuropathy' (CIDP), and are associated with anti-disialosyl antibodies. In our two cases, some paranodes seem to be associated with macrophages and we hypothesized that these lesions are in favor of a complement-mediated dysfunction/disruption of the nodal region due to disialosyl antibodies against gangliosides which are mainly located at the level of the axolemma of the paranode.

CIDP and hemopathies, an underestimated association.

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an immune-mediated and treatable disease that may be associated with various systemic conditions. Our objective is to describe the clinical, electrophysiological and pathological data of a series of patients with both CIDP and hemopathy. In this retrospective study, we analyzed 21 patients with CIDP and various hemopathies (malignant or not), consecutively observed for almost five years. In this particular context (with a risk of neurological complications of the hemopathy), a nerve biopsy was taken from each patient (after written consent). All the patients fulfilled the EAN/PNS electrodiagnostic criteria (2021) of CIDP: 16 with 'CIDP' and 2 with 'possible CIDP' (no data for 3 patients). For each patient, pathological analysis of nerve biopsy was compatible with the diagnosis of CIDP, and there was no evidence for hematological complication of the peripheral nervous system. In cases of peripheral neuropathy and malignant hemopathy, the possibility that the peripheral neuropathy is CIDP should not be overlooked because CIDP is clearly accessible to appropriate therapies, with high potential for a positive clinical response. If the diagnosis of CIDP is usually suspected clinically and electrophysiologically, it should be confirmed by pathological study (nerve biopsy) in certain cases. The management of such patients benefits from the collaboration of neurologists, hematologists and oncologists.

A Rational Approach for the Identification of Non-Hydroxamate HDAC6-Selective Inhibitors.

The human histone deacetylase isoform 6 (HDAC6) has been demonstrated to play a major role in cell motility and aggresome formation, being interesting for the treatment of multiple tumour types and neurodegenerative conditions. Currently, most HDAC inhibitors in preclinical or clinical evaluations are non-selective inhibitors, characterised by a hydroxamate zinc-binding group (ZBG) showing off-target effects and mutagenicity. The identification of selective HDAC6 inhibitors with novel chemical properties has not been successful yet, also because of the absence of crystallographic information that makes the rational design of HDAC6 selective inhibitors difficult. Using HDAC inhibitory data retrieved from the ChEMBL database and ligand-based computational strategies, we identified 8 original new non-hydroxamate HDAC6 inhibitors from the SPECS database, with activity in the low µM range. The most potent and selective compound, bearing a hydrazide ZBG, was shown to increase tubulin acetylation in human cells. No effects on histone H4 acetylation were observed. To the best of our knowledge, this is the first report of an HDAC6 selective inhibitor bearing a hydrazide ZBG. Its capability to passively cross the blood-brain barrier (BBB), as observed through PAMPA assays, and its low cytotoxicity in vitro, suggested its potential for drug development.

How the flexibility of human histone deacetylases influences ligand binding: an overview.

Over the past decade, human histone deacetylases (HDACs) have become interesting as therapeutic targets because of the benefits that their modulation might provide in aging-related disorders. Recently, studies using crystallography and computational chemistry have provided information on the structure and conformational changes related to HDAC-mediated recognition events. Through the description of the key mass and one-off movements observed in metal-dependent HDACs, here we highlight the impact of flexibility on drug-binding affinity and specificity. The collected information will be useful for not only a better understanding of the biological functions of HDACs, but also the conception of new selective binders.

Aurones as histone deacetylase inhibitors: identification of key features.

In this study, a total of 22 flavonoids were tested for their HDAC inhibitory activity using fluorimetric and BRET-based assays. Four aurones were found to be active in both assays and showed IC50 values below 20 µM in the enzymatic assay. Molecular modelling revealed that the presence of hydroxyl groups was responsible for good compound orientation within the isoenzyme catalytic site and zinc chelation.

The impact of dry eye disease on visual performance while driving.

PURPOSE: A specific simulator was used to assess the driving visual performance in patients with dry eye disease (DED) and to determine clinical predictors of visual impairments while driving. DESIGN: Prospective case-control study. METHODS: The study was conducted in the Center for Clinical Investigation of Quinze-Vingts National Ophthalmology Hospital, Paris, France. Twenty dry eye patients and 20 age- and sex-matched control subjects were included. Vision-related driving ability was assessed using a specific driving simulator displaying randomly located targets with a progressive increase in contrast to be identified. Other examinations included clinical examinations, serial measurements of corneal higher-order aberrations (HOAs), and vision-related quality-of-life questionnaire (Ocular Surface Disease Index [OSDI]). Data collected during driving test (ie, the number of targets seen, their position, and the response time) were compared between groups and analyzed according to clinical data, aberration dynamics, and quality-of-life index. RESULTS: The percentage of targets missed as well as average response time were significantly increased in DED patients as compared with controls (P < .01). More specifically, the visual function of DED patients was more impaired in specific situations, such as crossroad or roundabout approaches. In DED patients, the response time was found to positively correlate with the progression index for HOAs (P < .01) and with the OSDI "symptoms" subscale (P < .05). CONCLUSIONS: Degradation of ocular optical qualities related to DED is associated with visual impairments during driving. This study objectively has demonstrated the impact of tear film-related aberration changes on activities of daily living in DED.