Population dynamics of Achatina fulica in a peri-urban area adjacent to the Fiocruz Atlantic Forest Biological Station (EFMA), in Rio de Janeiro, Brazil, with report on Angiostrongylus cantonensis infection.

Achatina fulica is a species native to East Africa, considered one of the 100 worst invasive alien species in the world. The present study investigated the population of the snail, A. fulica, in a peri-urban area adjacent to the Fiocruz Atlantic Forest Biological Station (EFMA), in Jacarepaguá, Rio de Janeiro state, Brazil, focusing on population dynamics and the nematodes associated with this species. To this end, specimens were collected during four climatic seasons of the years 2021 and 2022 in three fixed 20 m × 10 m plots. The abundance of A. fulica in these areas was evaluated in relation to a set of environmental variables (temperature, relative humidity air, and soil pH and calcium). The abundance of snails infected by nematodes was also evaluated in relation to the season and body size of the specimens. The molluscs were found by active search, and standardized (15 minutes/three collections). Nematode larvae were extracted from the specimens by artificial digestion and identified by their external morphology and the sequencing of molecular markers. A total of 280 specimens of A. fulica were collected, with the highest abundances being recorded in the autumn and summer, although no significant relationship was found between the number of specimens collected and the environmental variables. Overall, 192 snails were infected by nematodes: Angiostrongylus cantonensis, Cruzia tentaculata and free-living nematodes, including Caenorhabditis briggsae. These findings demonstrate the epidemiological importance of the study area and the need to implement educational measures in the community, with the aim of controlling the local A. fulica population, thereby minimizing the risk of parasitic infection in the local human population.

Semperula wallacei (Mollusca, Veronicellidae) um hospedeiro natural recém-descoberto de Angiostrongylus cantonensis (Nematoda, Angiostrongylidae) na Bacia do Pacífico.

Semperula wallacei (Issel, 1874) is a species of terrestrial slug that occurs in southeast China and the Pacific Basin and is the only species of its genus that occurs beyond the Oriental region and to the east of Wallace's line in the Australian region, where it has probably been introduced. In this study, we report for the first time S. wallacei as an intermediate host for Angiostrongylus cantonensis (Chen, 1935) based on histological and molecular analyses of slugs from Tuamasaga, Samoa, deposited at the Medical Malacological Collection (Fiocruz-CMM). DNA was obtained from the deparafinized tissues scraped from specimen slides. Polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) targeted to the internal transcribed spacer 2 (ITS2) region were carried out using the restriction enzyme Cla I. The RFLP profile observed for our larval specimen of S. wallacei was identical to the profile previously established for A. cantonensis, demonstrating that S. wallacei can be naturally infected with A. cantonensis and is likely to be an intermediate host for this parasitic nematode species in the field. The potential for geographical range expansion of S. wallacei in the Pacific Basin, its small size, and the general role of veronicellids as crop pests and hosts of nematodes, indicate the significance of S. wallacei as an invasive species in the Pacific Basin. Our work also highlights the importance of biological collections for investigating the environmental impact of invasive species on agriculture, public health, and biodiversity conservation.

Mixed uremic osteodystrophy: an ill-described common bone pathology in patients with chronic kidney disease.

Renal osteodystrophy (ROD) starts early and progresses with further loss of kidney function in patients with chronic kidney disease (CKD). There are four distinct types of ROD based on undecalcified bone biopsy results. Adynamic bone disease and osteomalacia are the predominant forms of low bone turnover, while hyperparathyroid bone disease and mixed uremic osteodystrophy (MUO) are typically associated with high bone turnover. MUO is a prevalent but poorly described pathology that demonstrates evidence of osteomalacia on top of the high bone formation/resorption. The prevalence of MUO ranges from 5 to 63% among different studies. The pathogenesis of MUO is multi-factorial. Altered phosphate homeostasis, hypocalcemia, vitamin D deficiency, increased FGF-23, interleukins 1 and 6, TNF-α, amyloid, and heavy metal accumulation are the main inducers of MUO. The clinical findings of MUO are usually non-specific. The use of non-invasive testing such as bone turnover markers and imaging techniques might help to suspect MUO. However, it is usually impossible to precisely diagnose this condition without performing bone biopsy. The principal management of MUO is to control the maladaptive hyperparathyroidism along with correcting any nutritional mineral deficiencies that may induce mineralization defect. MUO is a common but still poorly understood bone pathology category; it demonstrates the complexity and difficulty in understanding ROD. A large prospective bone biopsy-based studies are needed for better identification as proper diagnosis and management would improve the outcome of patients with MUO.

The invasive giant African land snail, Achatina fulica (Gastropoda: Pulmonata): global geographical distribution of this species as host of nematodes of medical and veterinary importance.

The giant African land snail, Achatina fulica, is an important invasive species in many countries, where it causes losses in biodiversity and agriculture, as well as impacting the health of both humans and animals, as the intermediate host of medically important nematodes. The present study is based on a comprehensive review of the literature on the nematodes that have been found in association with A. fulica, worldwide. We searched a number of different databases and used the findings to investigate the methods used to extract and identify the nematodes, their larval stages, and environment and collecting procedures of the infected molluscs. Between 1965 and 2021, 11 nematode species were recorded in association with A. fulica in 21 countries. Most of the studies recorded associations between A. fulica and Angiostrongylus cantonensis, which causes cerebral angiostrongyliasis in humans and Aelurostrongylus abstrusus, which provokes pneumonia in felines. The nematodes were extracted primarily by artificial digestion with hydrochloric acid or pepsin, and identified based on their morphology or through experimental infection to obtain the adult. In most cases, the nematodes were at larval stage L3, and the infected A. fulica were collected from anthropogenic environments. The results demonstrate the importance of A. fulica as a host of nematodes of medical and veterinary importance, as well the contribution of anthropogenic environments to the occurrence of the parasites, and give information about the different methods used to collect and identify the nematodes found associated with this species.

Is Adynamic Bone Always a Disease? Lessons from Patients with Chronic Kidney Disease.

Renal osteodystrophy (ROD) is a common complication of end-stage kidney disease that often starts early with loss of kidney function, and it is considered an integral part in management of patients with chronic kidney disease (CKD). Adynamic bone (ADB) is characterized by suppressed bone formation, low cellularity, and thin osteoid seams. There is accumulating evidence supporting increasing prevalence of ADB, particularly in early CKD. Contemporarily, it is not very clear whether it represents a true disease, an adaptive mechanism to prevent bone resorption, or just a transitional stage. Several co-players are incriminated in its pathogenesis, such as age, diabetes mellitus, malnutrition, uremic milieu, and iatrogenic factors. In the present review, we will discuss the up-to-date knowledge of the ADB and focus on its impact on bone health, fracture risk, vascular calcification, and long-term survival. Moreover, we will emphasize the proper preventive and management strategies of ADB that are pivotal issues in managing patients with CKD. It is still unclear whether ADB is always a pathologic condition or whether it can represent an adaptive process to suppress bone resorption and further bone loss. In this article, we tried to discuss this hard topic based on the available limited information in patients with CKD. More studies are needed to be able to clearly address this frequent ROD finding.

Cerebrospinal fluid hypotension following fall in a child: Case report / Hipotensión del líquido cefalorraquídeo tras caída en un niño: caso clínico

CSF hypotension arises in the context of a leak of CSF which causes negative intracranial pressure. Sacral fractures result from high-energy trauma which are frequently underdiagnosed. A ten-year-old boy presented with hip pain, after a fall. He mobilized both lower limbs, reported no leg pain, irradiation nor lack of sphincter control. The neurological examination was normal. When asked to stand, he began biparietal headache, nausea and vomiting, which improved laying down. CT scan showed an occult intrasacral meningocele; the MRI revealed collections of CSF along the spine, a S3 fracture with potential laceration of the meningocele and opening of a CSF fistula. Our diagnosis was the CSF hypotension, secondary to the fistula opening. The diagnosis was challenging. The child first presented with symptoms of CSF hypotension without evident cause. The discovery of the meningocele led us to hypothesize the opening of a fistula, a rare diagnosis, later confirmed by MRI (AU)

La hipotensión del LCR surge en el contexto de una fuga de dicho líquido que causa presión intracraneal negativa. Las fracturas del sacro son originadas por traumatismos de alta energía que a menudo no se diagnostican. Un niño de diez años acudió con dolor de cadera tras una caída. Podía mover las piernas, no reportando ningún dolor en las mismas, ni irradiación o falta de control del esfínter. El examen neurológico resultó normal. Cuando se le pidió que se pusiera de pie comenzó a sufrir cefalea biparietal, náuseas y vómitos, que mejoraban al tumbarse. La TC mostró un meningocele intrasacro oculto. La RM reveló rastros de LCR a lo largo de la columna, fractura en S3 con laceración potencial del meningocele y apertura de una fístula de LCR. Nuestro diagnóstico fue hipotensión de LCR, secundaria a la apertura de la fístula. El diagnóstico resultó difícil. El niño presentó síntomas de hipotensión del LCR sin causa evidente. El descubrimiento del meningocele nos llevó a conjeturar la apertura de una fístula, un diagnóstico infrecuente que fue confirmado posteriormente mediante RM (AU)

On virus and nanomaterials - Lessons learned from the innate immune system - ACE activation in the invertebrate model Enchytraeus crypticus.

Current human research on COVID-19 - SARS-CoV-2 (Severe Acute Respiratory Syndrome-Corona Virus) showed that ACE2 (Angiotensin Converting Enzyme 2) is a functional receptor to which the spike proteins attach. Invertebrates have been exposed to a wide array of threats for millennia and their immune system has evolved to deal with these efficiently. The annelid Enchytraeus crypticus, a standard ecotoxicological species, is an invertebrate species where extensive mechanisms of response studies are available, covering all levels from gene to population responses. Nanomaterials (NMs) are often perceived as invaders (e.g. virus) and can enter the cell covered by a corona, triggering similar responses. We created a database on E. crypticus ACE gene expression, aiming to analyse the potential knowledge transfer between invertebrates and vertebrates. Total exposure experiments sum 87 stress conditions for 18 different nanomaterials (NMs). ACE expression following TiO2 NM exposure was clearly different from other NMs showing a clear (6-7 fold) ACE down-regulation, not observed for any other NMs. Other NMs, notably Ag NMs, and to some extent Cu NMs, caused ACE up-regulation (up to 4 fold). The extensive knowledge from response to NMs can support the immuno-research community, especially to develop therapies for virus that trigger the innate immune system.

Core stabilisation exercises reduce chronic low back pain in Air Force fighter pilots: a randomised controlled trial.

BACKGROUND: There is evidence that core stabilisation, strength and endurance training contribute to reduce low back pain in the general population. However, we are not aware of the effect of these exercises on fighter aviation pilots. Therefore, the present study aims to investigate the effects of an exercise protocol on chronic low back pain in Brazilian Air Force fighter pilots. Changes in neck pain, lumbar disability, range of motion, strength and resistance were also investigated. METHODS: Fourteen participants with chronic low back pain were randomised into two groups: stabilisation exercise group (SEG-n=7), exercise protocol twice a week for 12 weeks) and the regular exercise group (REG-n=7), which performed their own usual exercise routine. The evaluations were carried out before and after the training period. The primary outcome was the intensity of low back pain and the secondary outcomes were cervical pain, functional disability, range of motion, maximum isometric strength and trunk muscle resistance. RESULTS: The SEG had a significant reduction in low back pain compared with the REG (difference of 2.3 points, p=0.04) and a lower rate of cervical pain (difference of 2.5 points, p=0.01) at the end of the protocol. Maintenance of trunk muscle strength was also observed in the SEG over the period, while the REG presented a decrease in flexural strength to the right side (difference between groups: -3.7%, p=0.04). There were no differences in the rates of disability, range of motion or resistance to fatigue between groups. CONCLUSIONS: The stabilisation exercise programme focused on the core muscles was successful in decreasing the fighter pilots' chronic lumbar pain. Pilots are normally active; however, our results indicate that specific trunk training programmes should be offered considering the work needs of these subjects. CLINICAL TRIALS: 'Exercise protocol for pilots with back pain' (registered: 09 October 2018)-NCT03713814 (https://clinicaltrials.gov/ct2/show/NCT03713814).

Chronic Aerobic Training at Different Volumes in the Modulation of Macrophage Function and in vivo Infection of BALB/c Mice by Leishmania major.

Physical inactivity is one of the main causes of chronic diseases; however, strenuous exercise can induce immunosuppression. Several studies suggest that moderate amounts of exercise lead to a Th1 response, favoring the resolution of infections caused by intracellular microorganisms, while high volumes of exercise tend to direct the response to Th2, favoring infection by them. Leishmaniasis is a parasitic disease promoted by parasites of the Leishmania genus, with clinical manifestations that vary according to the species of the parasite and the immune response of the host. The experimental Leishmania major-BALB/C mouse model provides a good model for the resistance (Th1 response) or susceptibility (Th2 response) that determines the progression of this infection. The aim of this study was to evaluate the effect of aerobic training at different volumes on modulation of in vitro macrophage infection by L. major, as well as to assess the effect of high volume (HV) aerobic training on the development of L. major in vivo in BALB/c mice. Uninfected animals were submitted to various exercise volumes: none (SED), light (LV), moderate (MV), high (HV), very high (VHV), and tapering (TAP). The macrophages of these animals were infected by L. major and the LV and MV groups showed a decrease in the infection factor, while the VHV showed an increase in the infection factor, when treated with LPS. The cytokine concentration pattern measured in the supernatants of these macrophages suggested a predominant Th1 response profile in the LV and MV groups, while the Th2 profile predominated in the VHV and TAP groups. Groups of BALB/C mice infected with L. major were subjected to high volume (iHV) or non-periodized high volume (iNPHV) exercise or kept sedentary (iSED). The exercised animals suffered a significant increase in injuries caused by the parasites. The animals in the group submitted to high volume exercise (iHV) showed visceralization of the infection. These data strongly suggest that a very high volume of aerobic training increased the susceptibility of BALB/C mice to L. major infection, while moderate distribution of training loads promoted immunological balance, better controlling the infection by this parasite.

Nectar-dwelling microbes of common tansy are attractive to its mosquito pollinator, Culex pipiens L.

BACKGROUND: There is widespread interkingdom signalling between insects and microbes. For example, microbes found in floral nectar may modify its nutritional composition and produce odorants that alter the floral odor bouquet which may attract insect pollinators. Mosquitoes consume nectar and can pollinate flowers. We identified microbes isolated from nectar of common tansy, Tanacetum vulgare, elucidated the microbial odorants, and tested their ability to attract the common house mosquito, Culex pipiens. RESULTS: We collected 19 microbial isolates from T. vulgare nectar, representing at least 12 different taxa which we identified with 16S or 26S rDNA sequencing as well as by biochemical and physiological tests. Three microorganisms (Lachancea thermotolerans, Micrococcus lactis, Micrococcus luteus) were grown on culture medium and tested in bioassays. Only the yeast L. thermotolerans grown on nectar, malt extract agar, or in synthetic nectar broth significantly attracted Cx. pipiens females. The odorant profile produced by L. thermotolerans varied with the nutritional composition of the culture medium. All three microbes grown separately, but presented concurrently, attracted fewer Cx. pipiens females than L. thermotolerans by itself. CONCLUSIONS: Floral nectar of T. vulgare contains various microbes whose odorants contribute to the odor profile of inflorescences. In addition, L. thermotolerans produced odorants that attract Cx. pipiens females. As the odor profile of L. thermotolerans varied with the composition of the culture medium, we hypothesize that microbe odorants inform nectar-foraging mosquitoes about the availability of certain macro-nutrients which, in turn, affect foraging decisions by mosquitoes.

Anatomic and histologic analysis of paca larynx (Cuniculus paca, Linnaeus 1766) / [Análise anatômica e histológica da laringe da paca (Cuniculus paca, Linnaeus 1766)]

Paca (Cuniculus paca) has encouraged research as an experimental model both in the human medicine and veterinary, as well as the economic exploitation of its meat cuts, which favored its zootechnical use. There are no anatomical, microscopic descriptions and measurements of the larynx in this rodent. Eight pacas were dissected from the wild animal's sector of the Faculty of Agricultural and Veterinary Sciences of the University of the State of São Paulo. The larynx was observed located in the ventral region of the neck, ventral to the esophagus, connecting the pharynx to the trachea, with cylindrical and irregular shape. Laryngeal cartilages (epiglottic, thyroid, cricoid and arytenoid) are interconnected and have different shapes. Thyroid showed greater length and width, compared to the others. Laryngeal cartilages were submitted to histological processing and stained with hematoxylin-eosin and Masson's trichrome. The epiglottic cartilage was stained with toluidine blue. Laryngeal cartilages thyroid, cricoid and the lower portion of the arytenoids are of hyaline origin and, in contrast, the epiglottis and the upper portion of the arytenoids are elastic. This latter cartilage demonstrated taste buds. The results will be able to auxiliate in veterinary care and as well as the conservation programs for this rodent.(AU)

A paca (Cuniculus paca) tem encorajado inúmeras pesquisas, tornando-a modelo experimental tanto em humanos como na veterinária, além da exploração econômica de seus cortes cárneos, que favoreceu diretamente sua importância zootécnica. Não há descrições anatômicas, microscópicas e mensurações da laringe desse roedor. Foram dissecadas oito laringes de pacas, provenientes do setor de Animais Silvestres da Faculdade de Ciências Agrárias e Veterinárias - Universidade Estadual Paulista. Observou-se que a laringe localiza-se na região ventral do pescoço, ventral ao esôfago, conectando a faringe à traqueia, possuindo formato cilíndrico e irregular. As cartilagens laríngeas (epiglote, tireóide, cricóide e aritenóidea) são interligadas e possuem formatos variados. A cartilagem tireóide demonstrou-se maior em comprimento e largura, comparativamente às demais. As cartilagens laríngeas foram submetidas a processamento histológico e coradas em hematoxilina-eosina e tricrômio de Masson. A cartilagem epiglote foi corada em azul de toluidina. As cartilagens laríngeas tireóide, cricóide e a porção inferior das aritenóides são de origem hialina; em contrapartida, a epiglote e a porção superior das aritenóides, de origem elástica. Esta última cartilagem demonstrou corpúsculos gustativos. Os resultados poderão auxiliar tanto nos atendimentos veterinários quanto nos programas de conservação desse roedor.(AU)

[Use of radiopharmaceuticals in pediatrics: Specificities and recommandations of SoFRa (Société française de radiopharmacie)]. / Utilisation des médicaments radiopharmaceutiques en pédiatrie : spécificités et recommandations de la SoFRa (Société française de radiopharmacie).

Radiopharmaceuticals are commonly used in children in nuclear medicine. Because of physiological differences in growing children and their radiosensitivity, precautions must be taken throughout the medication use process. The aim of this work is to propose recommendations, under the aegis of the Société française de radiopharmacie (SoFRa), for each subsystem of the process, in order to ensure the safety of pediatric patients. Furthermore, an analysis of two surveys on diagnostic radiopharmaceuticals dosage used in different nuclear medicine departments in France is detailed. Recommendations for therapeutic radiopharmaceuticals are also provided. Specificities of the preparation for pediatric patients are discussed through the example of the radiopharmaceuticals for lung perfusion scintigraphy. The preparation of individual dose and administration are also described. In nuclear medicine, radiopharmacist's expertise is essential for patient safety. A multidisciplinary approach is necessary to secure pediatric radiopharmaceutical use process.

Single dose epidural methylprednisolone as a treatment and predictor of outcome following subsequent decompressive surgery in degenerative lumbosacral stenosis with foraminal stenosis.

Alternative treatments to surgery in canine degenerative lumbosacral stenosis (DLSS) remain limited and reliable predictors of outcome are lacking. The aims of this clinical trial were threefold: to assess the usefulness of single epidural steroid injection (ESI) in DLSS, to compare the outcomes of ESI and decompressive surgery, and evaluate ESI as a predictor of outcome following decompressive surgery. Dogs diagnosed with DLSS were prospectively recruited and administered an ESI. If clinical signs persisted or relapsed, decompressive surgery was recommended. Follow-up was obtained. Thirty-two dogs underwent ESI with 17 having subsequent surgery. Improvement after ESI was seen in 27/32 dogs (84.4%), with 17/22 (77.2%) relapsing within 6 months (n = 15/17 relapsing within 2 months). Five dogs failed to respond to ESI and another five (15.6%) presented a persistent post-ESI favourable response (mean follow-up time, 9.4 months). Post-surgical improvement occurred in all dogs. Outcome appeared more favourable following surgical decompression, with a trend towards reduced pain, increased mobility, and greater quality of life score. This study was unable to demonstrate that ESI could predict surgical outcome. ESI was confirmed as an effective treatment in most but not all cases, leading to transient alleviation of clinical signs for longer than previously reported. ESI provided a complete and apparently long-term sustained resolution of clinical signs in a subset of dogs. Despite this, there was indication that surgical decompression can lead to a more favourable outcome. Epidural steroid injection has a role in the management of DLSS dogs, particularly when surgery is not an option.

Efeitos tóxicos dos sedimentos do estuário do rio Capibaribe em embriões de zebrafish (Danio rerio) / Toxic effects of sediments of the Capibaribe estuary on zebrafish embryos (Danio rerio)

O presente estudo utilizou embriões de Danio rerio expostos aos elutriatos dos sedimentos estuarinos do rio Capibaribe, dos períodos chuvoso e seco, e analisou os efeitos letais, teratogênicos, bem como a frequência cardíaca. Os testes de toxicidade com os embriões seguiram as diretrizes da OECD 236. Mediante os resultados obtidos, a frequência cardíaca e a teratogenicidade foram os efeitos mais observados nos animais quando submetidos às amostras. Entre os efeitos teratogênicos, o retardo geral no desenvolvimento dos embriões foi o mais frequente durante as análises. Tais efeitos tóxicos se modificaram entre os pontos e entre os períodos de coleta. Essa variação de toxicidade pode estar relacionada à diversidade de atividades realizadas no entorno desse estuário, a influência do regime de chuvas, marés e correntes, indicando que a análise dos efeitos subletais e da teratogenicidade em embriões de D. rerio constitui bom parâmetro para avaliações de toxicidade de amostras ambientais.(AU)

The present study used Danio rerio embryos exposed to the elutriates of the estuarine sediments of the Rio Capibaribe, from the rainy and dry periods, where the lethal effects, teratogenic and heart rate were analyzed. Embryotoxicity tests followed the guidelines of OECD 236. Based on the results obtained, heart rate and teratogenicity demonstrated higher sensitivity to the samples. Among the teratogenic effects, the general delay in embryo development was the most frequent effect during the analyzes. These toxic effects changed between the points and between the collection periods. This variation of toxicity may be related to the diversity of activities carried out around this estuary, the influence of rainfall, tides, and currents, indicating the analysis of sublethal effects and teratogenicity in the D. rerio embryos are useful parameters for toxic evaluation of environmental samples.(AU)

Congenital external hydrocephalus in a dog.

A 4-year-old female Chihuahua was presented with progressive seizures, blindness and lethargy. Neurolocalisation was consistent with a diffuse brain lesion affecting the forebrain and cerebellum. MRI demonstrated dilation of the subarachnoid space dorsolaterally surrounding the cerebrum, filled with cerebrospinal fluid (CSF). Ventricular system size was normal, but mild cerebral atrophy was suspected. There was pachymeningeal contrast enhancement, but CSF analysis was unremarkable. This lesion was interpreted to be an external hydrocephalus of suspected congenital origin.

[What do we expect from Radiopharmacy software?] / Qu'attendons-nous des logiciels en radiopharmacie ?

The Radiopharmaceutical Health Products circuit or RHP (radiopharmaceutical drugs, radiopharmaceutical preparation and radioactive implantable medical devices) is a complex process that nowadays requires computerization. This circuit must be in accordance with both the legislation on medicinal products and the legislation on artificial radioelements. It is acknowledged that computerization of the circuit; possibly different within each organization, provides assistance to stakeholders: pharmaceutical analysis of prescription, pharmaceutical preparation and preparation of doses to be dispensed and waste management for example. The software also allows real-time monitoring of the activity and traceability of the various pharmaceutical processes. In addition, they are generally interfaced with equipment used routinely: dose calibrator, dose dispensing equipment. In the absence of any legislation for these software products, which are not considered either as medical devices or as software to assist prescription or dispensation, a working group, under the aegis of the Société Française de Radiopharmacie (SoFRa), has written a minimum set of specifications for these radiopharmaceutical software products. The analyses of the risk maps of different hospital structures allowed a global analysis and synthesis of the different processes, settings, interfaces and requirements for the proper use of these software. The specifications include the very specific requirements of radiopharmacy (notion of radioactive decay, complex preparations with chemical synthesis, traceability.) and will allow software publishers to propose tools adapted to our practice and the RHP circuit.

Calibration of thermocouple-based scanning thermal microscope in active mode (2ω method).

We present a procedure dedicated to the calibration of a scanning thermal microscopy probe operated in an active mode and a modulated regime especially for the measurement of solid material thermal conductivities. The probe used is a microthermocouple wire mounted on a quartz tuning fork. Measurements on reference samples are performed successively in vacuum and ambient air conditions revealing a clear difference in the dependence of the thermal interaction between the probe and the sample on the sample properties. Analytical modeling based on the resolution of the heat equation in the wire probe and a description of the thermal interaction using a network of thermal conductances are used to fit experimental data and analyze this difference. We have experimentally verified that the effective thermal contact radius of the probe tip depends on the sample thermal conductivity in ambient conditions, whereas it remains constant in vacuum. We have defined the measurement range of the technique based on the decrease in the probe sensitivity at high thermal conductivities. Considering the experimental noise of our electrical device, it is shown that the maximum measurable value of thermal conductivity is near 23 W m-1 K-1 in vacuum and 37 W m-1 K-1 in ambient air conditions. Moreover, the lowest uncertainties are obtained for thermal conductivities below 5 W m-1 K-1 typically.