Snake and arthropod venoms: Search for inflammatory activity in human cells involved in joint diseases

Most anti-inflammatory drugs currently adopted to treat chronic inflammatory joint diseases can alleviate symptoms but they do not lead to remission. Therefore, new and more efficient drugs are needed to block the course of joint inflammatory diseases. Animal venoms, rich in bioactive compounds, can contribute as valuable tools in this field of research. In this study, we first demonstrate the direct action of venoms on cells that constitute the articular joints. We established a platform consisting of cell-based assays to evaluate the release of cytokines (IL-6, IL-8, TNFα, IL-1β, and IL-10) by human chondrocytes, synoviocytes and THP1 macrophages, as well as the release of neuropeptides (substance-P and β-endorphin) by differentiated sensory neuron-like cells, 24 h after stimulation of cells with 21 animal venoms from snake and arthropod species, sourced from different taxonomic families and geographic origins. Results demonstrated that at non-cytotoxic concentrations, the venoms activate at varying degrees the secretion of inflammatory mediators involved in the pathology of articular diseases, such as IL-6, IL-8, and TNF-α by chondrocytes, synoviocytes, and macrophages and of substance P by neuron-like cells. Venoms of the Viperidae snake family were more inflammatory than those of the Elapidae family, while venoms of Arthropods were less inflammatory than snake venoms. Notably, some venoms also induced the release of the anti-inflammatory IL-10 by macrophages. However, the scorpion Buthus occitanus venom induced the release of IL-10 without increasing the release of inflammatory cytokines by macrophages. Since the cell types used in the experiments are crucial elements in joint inflammatory processes, the results of this work may guide future research on the activation of receptors and inflammatory signaling pathways by selected venoms in these particular cells, aiming at discovering new targets for therapeutic intervention.

Scorpion sting envenomation outbreak in Mexico. Strategies for prevention and control

In Mexico occurs 25% of all worldwide cases of scorpion sting envenomation (SSE). An outbreak of SSE was identified in Villa Unión, Sinaloa, Mexico. The objective of this study is to describe the outbreak, and prevention and control strategies implemented. The design was a cross-sectional study. Eligibility criteria included confirmed cases (n = 425) identified from the date the outbreak was recognized (from November 08, 2023 to July 10, 2023). The cases from Villa Unión (n = 231) were included for the analysis of epidemiological and clinical findings. The research followed the recommendations of the Initiative Reporting of studies Conducted Using Observational Routinely collected Data (RECORD). Of the total cases (n = 425), 398 (93.6%) were from the municipality of Mazatlán, and 231 (58%) were from Villa Unión. The incidence rate was 13.64 per 1000 persons. The average cases per week was 51.5(SD ± 12). The male-to-female ratio was 3:4, the average age was 30.7(SD ± 19) years. Most of cases occurred in the 25-44 age group. The sting occurred mostly inside houses (n = 200, 86.5%). The predominant symptoms were local pain (95.2%), and local paresthesia (75.8%). The Case fatality rate was 0%. Implementation of prevention and control strategies based on field epidemiological research and scientific evidence are necessary to reduce the incidence and prevent fatal complications.

Analysis of antibodies avidity for Tityus serrulatus scorpion venom in antivenom production and its potential for application as a potency test

Antivenoms are the only specific medication for neutralizing toxins present in venom of animals such scorpions and snakes through antigen-antibody binding. Several analyses are carried out throughout its production in order to ensure the quality and effectiveness of the antivenom that will be administered to the patient. One of these is the potency assay, which is performed to assess the ability of antivenoms to neutralize the toxic effects of the venom injected in mice. The substitution of in vivo for in vitro assays such as ELISA has been presented by other authors, bringing several advantages such as the reduction in the use of animals, in costs and in the duration of the assays. However, the avidity index of antivenom antibodies determined by ELISA has not yet been applied for this purpose. Therefore, the objective of this study was to evaluate the avidity of sera from hyperimmunized horses with crude Tityus serrulatus venom, a scorpion species associated with the most serious accidents in Brazil, and its potential for application as a potency test replacing the in vivo assay. The avidity ELISA proved to be interesting for monitoring the binding strength of antibodies produced by horses in hyperimmune plasma production programs. It was possible to verify oscillations in antibody avidity that occurred along the immunization cycles, differences between novice and veteran horses, maturation of antibody avidity, and correlation between avidity index and antibody titre. Similar results were obtained for crude venom and purified Ts1 toxin. In addition, the avidity ELISA apparently demonstrated potential for application as a potency test in the initial stage of antivenom production. However, more studies are necessary.

Neutralization of Centruroides tecomanus scorpion venom by the use of two human recombinant antibody fragments

The first toxic component identified against mammals in the venom from Centruroides tecomanus scorpion from Colima, Mexico was Ct1a toxin, which was neutralized by human single chain variable fragment (scFv) RAS27. Venom characterization from these scorpions collected on the Pacific coast of Colima, enabled the identification of a second component of medical importance named Ct71 toxin. Amino acid sequence of Ct71 shares a high identity with Chui5 toxin from C. huichol scorpion, which was neutralized by scFv HV. For this reason, the kinetic parameters of interaction between Ct71 toxin and scFv HV were determined by surface plasmon resonance. Results showed a significantly higher affinity for Ct71 as compared to Chui5. As expected, this toxin was neutralized by scFv HV. The injection of a mixture of scFvs HV and RAS27, resulted in the neutralization of C. tecomanus venom, corroborating that human recombinant antibody fragments can efficiently contribute to the neutralization of medically important toxins and their respective venoms from Mexican scorpions.

Captive Maintenance and Venom Extraction of Tityus serrulatus (Brazilian Yellow Scorpion) for Antivenom Production

Scorpion envenomation is a public health problem in several tropical and subtropical countries. Tityus serrulatus Lutz and Mello, 1922 (Brazilian yellow scorpion) are responsible for approximately 150,000 envenoming cases per year in Brazil, of which 10% require antivenom treatment to reverse life-threatening venom effects. Therefore, thousands of T. serrulatus individuals are maintained under controlled captivity conditions for venom extraction, subsequently used in the production of the national supply of scorpion antivenom. Instituto Butantan is the main antivenom-manufacturing laboratory in Brazil, providing about 70,000 vials of scorpion antivenom for the Brazilian health system. Thus, the husbandry protocols and venom extraction methodologies are key points for the success of large-scale, standardized venom production. The objective of this article is to describe the captivity protocols of T. serrulatus husbandry, encompassing the husbandry routine and the venom extraction procedures, following good manufacturing practices, and ensuring animal welfare. These practices allow for the maintenance of up to 20,000 animals in captivity, with a routine of 3,000 to 5,000 scorpions milked monthly according to antivenom manufacturing demand, achieving an average of 90% of positive extraction.

Ethnomedicines for the treatment of scorpion stings: A perspective study

ETHNOPHARMACOLOGICAL RELEVANCE

Scorpion sting is a public health concern with limited clinical symptomatic treatment. The clinical treatment uses anti-scorpion antivenom and prazosin (α-adrenergic inhibitor), often in combination with insulin, to reduce scorpion venom-induced hyperglycemia and other complications. However, these therapies also possess some limitations, necessitating urgent exploration of ethnomedicines, mainly traditional medicinal plants, to treat scorpion stings. Unfortunately, several conventional treatments are not scientifically validated, thus raising questions about their quality and utility. Therefore, pharmacological re-assessment of such medicinal plants to alleviate scorpion stings' complications is essential.

AIM OF THE STUDY

The principal objectives of this study are to provide a brief overview of medically important scorpions of the world, outline the extant traditional practices, and comprehensively review plants used in conventional ethnic medicines to treat scorpion stings over time. Modern technological advances in identifying and characterizing plant bioactive molecules are also mentioned in this review.

MATERIALS AND METHODS

The traditionally used medicinal plants against scorpion stings were reviewed from the available literature in the database. The Plant List (http://www.theplantlist.org/) was used to validate the scientific names of the plants mentioned in this study. The search targeted literature on conventional treatments and crude plant extracts or their bioactive components with proven neutralization capacity against scorpion stings. Search words used were 'scorpion sting,' 'treatment for a scorpion sting,' 'antivenom and scorpion sting,' 'traditional treatment for scorpion stings, and 'natural compounds against scorpion stings'.

RESULTS

A list of more than 200 medicinal plants traditionally used in several countries for treating scorpion stings is presented in this review. Though some myth-based remedies are practiced to treat scorpion stings, no empirical evidence exists to validate this aspect of traditional knowledge. Only 38 traditional medicinal plant extracts have been tested under in-vivo and in-vitro conditions to determine their neutralization potency of scorpion envenomation. Although a few bioactive plant constituents showing scorpion venom neutralization potency have been characterized, they are not yet commercially available for clinical application.

CONCLUSIONS

There is tremendous potential locked in medicinal plants' traditional knowledge for scorpion envenomation treatment. Translating this knowledge into the clinical application will require pharmacological reassessment, in tandem with isolation and characterization of active compounds to prove their prophylactic prowess. Almost equally important would be the formulation of stringent strategies to conserve such medicinal plants from overexploitation.

Ethnomedicines for the treatment of scorpion stings: A perspective study

ETHNOPHARMACOLOGICAL RELEVANCE

Scorpion sting is a public health concern with limited clinical symptomatic treatment. The clinical treatment uses anti-scorpion antivenom and prazosin (α-adrenergic inhibitor), often in combination with insulin, to reduce scorpion venom-induced hyperglycemia and other complications. However, these therapies also possess some limitations, necessitating urgent exploration of ethnomedicines, mainly traditional medicinal plants, to treat scorpion stings. Unfortunately, several conventional treatments are not scientifically validated, thus raising questions about their quality and utility. Therefore, pharmacological re-assessment of such medicinal plants to alleviate scorpion stings' complications is essential.

AIM OF THE STUDY

The principal objectives of this study are to provide a brief overview of medically important scorpions of the world, outline the extant traditional practices, and comprehensively review plants used in conventional ethnic medicines to treat scorpion stings over time. Modern technological advances in identifying and characterizing plant bioactive molecules are also mentioned in this review.

MATERIALS AND METHODS

The traditionally used medicinal plants against scorpion stings were reviewed from the available literature in the database. The Plant List (http://www.theplantlist.org/) was used to validate the scientific names of the plants mentioned in this study. The search targeted literature on conventional treatments and crude plant extracts or their bioactive components with proven neutralization capacity against scorpion stings. Search words used were 'scorpion sting,' 'treatment for a scorpion sting,' 'antivenom and scorpion sting,' 'traditional treatment for scorpion stings, and 'natural compounds against scorpion stings'.

RESULTS

A list of more than 200 medicinal plants traditionally used in several countries for treating scorpion stings is presented in this review. Though some myth-based remedies are practiced to treat scorpion stings, no empirical evidence exists to validate this aspect of traditional knowledge. Only 38 traditional medicinal plant extracts have been tested under in-vivo and in-vitro conditions to determine their neutralization potency of scorpion envenomation. Although a few bioactive plant constituents showing scorpion venom neutralization potency have been characterized, they are not yet commercially available for clinical application.

CONCLUSIONS

There is tremendous potential locked in medicinal plants' traditional knowledge for scorpion envenomation treatment. Translating this knowledge into the clinical application will require pharmacological reassessment, in tandem with isolation and characterization of active compounds to prove their prophylactic prowess. Almost equally important would be the formulation of stringent strategies to conserve such medicinal plants from overexploitation.

Imparting knowledge is no more considered a paramount contribution

I have been practising medicine in an under-served rural setting since 1976, and have published around 109 papers in PubMed-indexed journals - including The Lancet, BMJ, NEJM and several tropical medicine journals - on scorpion and snakebite cases causing acute life-threatening conditions. I have researched in detail, with restricted resources, the acute clinical effects of envenomation and management of scorpion and snakebite cases [1, 2]. In Mahad, the fatality rate due to refractory heart failure arising from autonomic storm evoked by scorpion venom was previously 30% [3]. Since the advent of prazosin and scorpion antivenom, it has dropped to less than 1% [4]. Similarly, fatalities due to snakebite poisoning have been reduced from 18% to 5.

Peptides with Diverse Functions from Scorpion Venom: A Great Opportunity for the Treatment of a Wide Variety of Diseases

Toxicology Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran

The venom glands are a rich source of biologically important peptides with pharmaceutical properties. Scorpion venoms have been identified as a reservoir for components that might be considered as great candidates for drug development. Pharmacological properties of the venom compounds have been confirmed in the treatment of different disorders. Ion channel blockers and AMPs are the main groups of scorpion venom components. Despite the existence of several studies about scorpion peptides, there are still valuable components to be discovered. Additionally, owing to the improvement of proteomics and transcriptomics, the number of peptide drugs is steadily increasing, which reflects the importance of these medications. This review evaluates available literatures on some important scorpion venom peptides with pharmaceutical activities. Given that the last three years have been dominated by the COVID-19 from the medical/pharmaceutical perspective, scorpion compounds with the potential against the coronavirus 2 (SARS-CoV-2) are discussed in this review.

Spatial Analysis in Areas with High Occurrence of Accidents Caused by Tityus serrulatus and Tityus bahiensis (Scorpiones: Buthidae) in Brazil

INTRODUCTION

In Brazil, scorpion stings are recorded in high numbers with an increasing epidemiological situation in most municipalities. In the present study, data between 1998 and 2018 in Americana, São Paulo, were analyzed.

METHODS

In total, 4122 records on scorpion stings were georeferenced using a Garmin eTREX 30X global positioning system device, with WGS84 datum projection and Universal Transverse Mercator zone 23S. Multiple Poisson regression was used to explore the relationship between the incidence rates of stings and urban planning areas (UPAs). Eight quantitative variables were used to establish the environmental and anthropic characterization of UPAs associated or not associated with scorpionism. A spatial analysis was performed for geoprocessing maps of Americana using spatial statistics tools (optimized hotspot analysis and kernel density function) from cartographic clusters in the ArcMap software, version 10.5.

RESULTS

The optimized hotspot analysis tool identified spatial clusters with high values of the incidence of scorpion stings in the surroundings of all UPAs in the municipality. The estimation of the kernel function of event intensity showed a wide distribution of stings across the area of the entire municipal territory, with UPA-02 and UPA-06 exhibiting the highest occurrence of scorpion stings. Six significant hotspots were established as highest-event-density areas (with occurrences of 160-270) and were contiguous to 4 environmental protection areas, located in more peripheral regions, and to 2 municipal cemeteries, which were located in urban central areas.

CONCLUSIONS

This analysis showed that the risk of scorpion stings in different Americana's UPAs has increased occurrence and incidence intensity.

French Scorpionism (Mainland and Oversea Territories): Narrative Review of Scorpion Species, Scorpion Venom, and Envenoming Management

Sixty-seven scorpion species have been described in France and its territories, where they have been found to be heterogeneously distributed. Indeed, only one species can be found on Réunion Island, while 38 species exist in French Guiana. The number of stings is also heterogenous, with up to 90 stings per 100,000 inhabitants occurring annually. Scorpion species can frequently be determined through simple visual factors, including species of medical importance (i.e., Buthus, Centruroides and Tityus). Scorpion venom is composed of local enzymes and peptides with a cysteine-stabilized α/β motif (NaTxs, Ktxs, Calcines), which allow for venom diffusion and the prey's incapacitation, respectively. Harmful scorpion species are limited to Centruroides pococki in the French West Indies, which can induce severe envenoming, and the Tityus obscurus and Tityus silvestris in French Guiana, which can cause fatalities in children and can induce severe envenoming, respectively. Envenomation by one of these scorpions requires hospital monitoring as long as systemic symptoms persist. Typical management includes the use of a lidocaine patch, pain killers, and local antiseptic. In the case of heart failure, the use of dobutamine can improve survival, and pregnant women must consult an obstetrician because of the elevated risk of preterm birth or stillbirth. France does not have scorpion antivenom, as scorpion stings are generally not fatal.

Synthesis of Scyllatoxin-Based BH3 Domain Mimetics with Diverse Patterns of Native Disulfide Bonds

This article outlines the design and development of scyllatoxin (ScTx)-based BH3 domain mimetics with diverse patterns of native disulfide bonds. More specifically, this method summarizes the total chemical synthesis of ScTx-based peptides that contain zero, one, two, or three disulfide linkages, including techniques to generate variants with any combination of native disulfides. Each peptide reported herein is generated on solid-phase support using microwave-assisted coupling procedures, and all reaction parameters related to the peptide synthesis are described in detail. The various disulfide patterns of the ScTx-based constructs are established during peptide synthesis and are ultimately verified by mass analysis of trypsin-digested fragments. The BH3 domain mimetics developed herein were generated by transposing residues from the helical BH3 domain of the pro-apoptotic BCL2 protein Bax to the α-helix of wild-type ScTx. Interestingly, we found that the relative binding affinities of ScTx-Bax peptides for the anti-apoptotic BCL2 protein Bcl-2 (proper) were heavily influenced by the number and position of disulfide linkages within the ScTx-Bax sequence. As a consequence, we were able to utilize ScTx-Bax BH3 domain mimetics with varied patterns of disulfide bonds to survey how structural rigidity within the helical Bax BH3 domain affects binding to promiscuous anti-apoptotic BCL2 proteins. More broadly, the ability to generate ScTx-based molecules that contain any combination of native disulfide bonds expands the utility of such constructs as tools to study the molecular nature of protein-protein interactions. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Synthesis and characterization of ScTx-based Bax BH3 domain mimetics Basic Protocol 2: Oxidation of ScTx-Bax BH3 domain mimetics containing one, two, or three disulfide linkages Support Protocol: Mapping of disulfide linkages in oxidized ScTx-Bax BH3 domain mimetics.

BmK DKK13, A Scorpion Toxin, Alleviates Pain Behavior in a Rat Model of Trigeminal Neuralgia by Modulating Voltage-Gated Sodium Channels and MAPKs/CREB Pathway

BmK DKK13 (DKK13) is a mutated recombinant peptide, which has a significant antinociception in a rat model of the inflammatory pain. The purpose of this study was to evaluate the antinociceptive effect of DKK13 on trigeminal neuralgia (TN) in rats. Male Sprague-Dawley (SD) rats were treated with the chronic constriction injury of the infraorbital nerve (IoN-CCI) model to induce stable symptoms of TN. DKK13 (1.0 mg/kg, 2.0 mg/kg and 4.0 mg/kg, i.v.) or morphine (4.0 mg/kg, i.v.) was administered by tail vein once on day 14 after IoN-CCI injury. Behavioral tests, electrophysiology and western blotting were performed to investigate the role and underlying mechanisms of DKK13 on IoN-CCI model. Behavioral test results showed that DKK13 could significantly increase the mechanical pain and thermal radiation pain thresholds of IoN-CCI rats and inhibit the asymmetric spontaneous pain scratching behavior. Electrophysiological results showed that DKK13 could significantly reduce the current density of Nav1.8 in the ipsilateral side of trigeminal ganglion (TG) neurons in IoN-CCI rats, and the steady-state activation and inactivation curves of Nav1.8 shifted, respectively, to the direction of hyperpolarization and depolarization. Western blotting results showed that DKK13 significantly reduced the expression of Nav1.8 and the phosphorylation levels of key proteins of MAPKs/CREB pathway in TG tissues of IoN-CCI rats. In brief, DKK13 has a significant antinociceptive effect on IoN-CCI rats, which may be achieved by changing the dynamic characteristics of Nav1.8 channel and regulating the protein phosphorylation in MAPKs/CREB pathway.

Serum Trimethylamine N-oxide and the Diversity of the Intestinal Microbial Flora in Type 2 Diabetes Complicated by Diabetic Kidney Disease

BACKGROUND

Trimethylamine N-oxide (TMAO) serves as a metabolite of intestinal bacteria as well as a urotoxin influencing the prognosis of chronic kidney disease (CKD), which has become a research hotspot in the field of kidney disease. This study preliminarily explored the alternations of the microbial flora and serum TMAO in patients with type 2 diabetes mellitus (T2DM) complicated with diabetic kidney disease (DKD).

METHODS

Seventeen T2DM patients at the Affiliated Hospital of Zunyi Medical University between September 2018 and February 2019 were included. Among these patients, 8 patients had T2DM complicated with DKD. Eight healthy volunteers constituted the control group. Fresh stool was collected for Illumina sequencing. Based on the sequencing outcomes, the flora diversity and species differences were analyzed. Serum TMAO, cystatin C, urinary albumin/urine creatinine ratios (ACRs), and routine biochemical outcomes were also compared.

RESULTS

The DKD group exhibited a significantly higher TMAO level than the remaining groups. The high-TMAO group had a significantly increased ACR level compared with the low-TMAO group. TMAO positively correlated with the ACR. Compared with the control group, the DKD group exhibited a decreased flora diversity. At the genus level, both the T2DM group and the DKD group showed decreased numbers of Alloprevotella and Megasphaera compared with the control group. The difference in Megasphaera between the DKD group and the control group was significant.

CONCLUSIONS

The alternation of the intestinal microbial flora may participate in the development of DKD, and TMAO and chronic inflammation might be important factors for DKD development.

Biochemical characterization and insecticidal activity of isolated peptides from the venom of the scorpion Centruroides tecomanus

The venom of scorpions is a mixture of components that constitute a source of bioactive molecules. The venom of the scorpion Centruroides tecomanus contains peptides toxic to insects, however, to date no toxin responsible for this activity has yet been isolated and fully characterized. This communication describes two new peptides Ct-IT1 and Ct-IT2 purified from this scorpion. Both peptides contain 63 amino acids with molecular weight 6857.85 for Ct-IT1 and 6987.77 Da for Ct-IT2. The soluble venom was separated using chromatographic techniques of molecular size exclusion, cationic exchange, and reverse phase chromatography, allowing the identification of at least 99 components of which in 53 the insecticidal activity was evaluated. The LD₅₀ determined for Ct-IT1 is 3.81 μg/100 mg of cricket weight, but low amounts of peptides (0.8 μg of peptide) already cause paralysis in crickets. The relative abundance of these two peptides in the venom is 2.1% for Ct-IT1 and 1% for Ct-IT2. The molecular masses and N-terminal sequences of both insecticidal toxins were determined by mass spectrometry and Edman degradation. The primary structure of both toxins was compared with other known peptides isolated from other scorpion venoms. The analysis of the sequence alignments revealed the position of a highly conserved amino acid residue, Gly39, exclusively present in anti-insect selective depressant β-toxins (DBTXs), which in Ct-IT1 and Ct-IT2 is at position Gly40. Similarly, a three-dimensional structure of this toxins was obtained by homology modeling and compared to the structure of known insect toxins of scorpions. An important similarity of the cavity formed by the trapping apparatus region of the depressant toxin LqhIT2, isolated from the scorpion Leiurus quinquestriatus hebraeus, was found in the toxins described here. These results indicate that Ct-IT1 and Ct-IT2 toxins have a high potential to be evaluated on pests that affect economically important crops to eventually consider them as a potential biological control method.

Engineered expression of the invertebrate-specific scorpion toxin AaHIT reduces adult longevity and female fecundity in the diamondback moth Plutella xylostella

BACKGROUND

Previous genetic pest management (GPM) systems in diamondback moth (DBM) have relied on expressing lethal proteins ('effectors') that are 'cell-autonomous', that is, they do not leave the cell in which they are expressed. To increase the flexibility of future GPM systems in DBM, we aimed to assess the use of a non-cell-autonomous, invertebrate-specific, neurotoxic effector - the scorpion toxin AaHIT. This AaHIT effector was designed to be secreted by expressing cells, potentially leading to effects on distant cells, specifically neuromuscular junctions.

RESULTS

Expression of AaHIT caused a 'shaking/quivering' phenotype that could be repressed by provision of an antidote (tetracycline): a phenotype consistent with the AaHIT mode-of-action. This effect was more pronounced when AaHIT expression was driven by the Hr5/ie1 promoter (82.44% of males, 65.14% of females) rather than Op/ie2 (57.35% of males, 48.39% of females). Contrary to expectations, the shaking phenotype and observed fitness costs were limited to adults in which they caused severe reductions in mean longevity (-81%) and median female fecundity (-93%). Quantitative polymerase chain reactions of AaHIT expression patterns and analysis of piggyBac-mediated transgene insertion sites suggest that restriction of the observed effects to the adult stages may be due to the influence of the local genomic environment on the tetO-AaHIT transgene.

CONCLUSION

We demonstrated the feasibility of using non-cell-autonomous effectors within a GPM context for the first time in Lepidoptera, one of the most economically damaging orders of insects. These findings provide a framework for extending this system to other pest Lepidoptera and to other secreted effectors. © 2021 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Scorpions and scorpion sting envenoming (scorpionism) in the Arab Countries of the Middle East

The twelve Arab countries of the Middle East are inhabited by 117 species of scorpions of varying medical importance within six families. Scorpion stings are a very common occurrence throughout the region. Twenty-two scorpion species are considered to be dangerously venomous, causing potentially life threatening stings. Accessible literature in English and Arabic on scorpions, scorpion stings and available antivenoms was reviewed to document the scorpion fauna and scorpion stings in each country. Saudi Arabia, Iraq and Jordan report the highest numbers of stings and envenomings. Clinically, the most important toxins in Old World scorpion venoms are α-toxins that target voltage-gated sodium (Na_v) channels at neurotoxin binding site 3, causing sympathetic excitation and the endogenous release of catecholamines that is responsible for transient, but life-threatening myocardial damage. Most victims of scorpion stings suffer severe local pain, but a few, especially children, develop systemic envenoming which, in the case of most Middle Eastern buthid species, such as Androctonus and Leiurus species, is dominated by the cardiovascular and respiratory consequences of hypercatecholinaemic myocarditis. Other syndromes include paralysis (Parabuthus leiosoma), coagulopathy (Nebo hierichonticus and Hemiscorpius species), and local tissue damage, haemolysis and acute kidney injury (H. lepturus). Early antivenom treatment is recommended but its value remains controversial. However, intensive care, with the ancillary use of vasoactive drugs such as prazosin and dobutamine, has proved effective.

Clinical profile of confirmed scorpion stings in a referral center in Manaus, Western Brazilian Amazon

Scorpion envenomations are a major public health problem in Brazil, and most medically important cases are attributable to the Tityus genus. The objective of this study is to describe the clinical and epidemiological aspects of a series of 151 cases of confirmed scorpion stings, which were treated at the hospitals of two cities in the Western Brazilian Amazon, between June 2014 and December 2019. This study shows that the genus Tityus was the most prevalent. Tityus (Atreus) metuendus (Pocock, 1897) was responsible for the greatest number of cases (68.2%), followed by Tityus (Archaeotityus) silvestris (Pocock, 1897) (14.6%). Most of the envenomations involved males (53.6%), and analysis showed a slight predominance in the group from 40 to 49 years (22.5%). The most affected body regions were feet (49.0%) and hands (31.8%). The time elapsed between the accident and medical care was ≤6 h in 92.1% of cases. Regarding clinical severity, classes I (80.8%) and II (15.9%) predominated. However, there were five (3.3%) class III cases; four for T. metuendus and one for T. silvestris. The most frequent local and systemic manifestations were, respectively, pain (84.1%), paresthesia (34.4%) and mild edema (25.8%), and nausea (9.3%) and myoclonia (8.6%). The clinical manifestations were similar among the patients stung by the different species of scorpions. There were no differences between the manifestations of envenomation caused by T. metuendus, T. silvestris and T. raquelae. For victims of T. apiacas, a higher frequency of piloerection and myoclonia was observed, and was described by the affected patients as a 'sensation of receiving an electric shock' throughout the body. No deaths were registered. The species of greatest epidemiological importance in Manaus is T. metuendus, a species that leads to clinical pictures that do not differ substantially from those observed in other Brazilian regions. T. apiacas causes neurological manifestations that differed from other Tityus species. Our findings suggest that the available antivenoms have little effectiveness when used in the treatment of envenomations by some Amazonian scorpions.

Defensive Venoms: Is Pain Sufficient for Predator Deterrence?

Pain, though unpleasant, is adaptive in calling an animal’s attention to potential tissue damage. A long list of animals representing diverse taxa possess venom-mediated, pain-inducing bites or stings that work by co-opting the pain-sensing pathways of potential enemies. Typically, such venoms include toxins that cause tissue damage or disrupt neuronal activity, rendering painful stings honest indicators of harm. But could pain alone be sufficient for deterring a hungry predator? Some venomologists have argued “no”; predators, in the absence of injury, would “see through” the bluff of a painful but otherwise benign sting or bite. Because most algogenic venoms are also toxic (although not vice versa), it has been difficult to disentangle the relative contributions of each component to predator deterrence. Southern grasshopper mice (Onychomys torridus) are voracious predators of arthropods, feeding on a diversity of scorpion species whose stings vary in painfulness, including painful Arizona bark scorpions (Centruroides sculpturatus) and essentially painless stripe-tailed scorpions (Paravaejovis spinigerus). Moreover, southern grasshopper mice have evolved resistance to the lethal toxins in bark scorpion venom, rendering a sting from these scorpions painful but harmless. Results from a series of laboratory experiments demonstrate that painful stings matter. Grasshopper mice preferred to prey on stripe-tailed scorpions rather than bark scorpions when both species could sting; the preference disappeared when each species had their stingers blocked. A painful sting therefore appears necessary for a scorpion to deter a hungry grasshopper mouse, but it may not always be sufficient: after first attacking and consuming a painless stripe-tailed scorpion, many grasshopper mice went on to attack, kill, and eat a bark scorpion even when the scorpion was capable of stinging. Defensive venoms that result in tissue damage or neurological dysfunction may, thus, be required to condition greater aversion than venoms causing pain alone.

Level of depression, anxiety and stress in patients with intrauterine adhesions in Hunan Province, China: A cross-sectional study

Background

The incidence of intrauterine adhesions has been increasing in recent years, seriously affecting women’s health. This study aimed to investigate the psychological status and identify risk factors associated with high psychological distress in patients with intrauterine adhesions.

Methods

A cross-sectional study was conducted in Hunan Province, China. A total of 258 patients who presented with intrauterine adhesions between February and May 2018 were included. Data were collected by a questionnaire packet that included the Depression Anxiety Stress Scale, the Medical Coping Mode Questionnaire, and demographic and clinical information. Descriptive statistics, t-tests, one-way ANOVA, Pearson’s correlations and multiple linear stepwise regression were employed in this study.

Results

Among 258 participants, the detection rates of mild depression and moderate to extremely severe depression were 10.1% and 10.5%, respectively; the detection rates of mild anxiety and moderate to extremely severe anxiety were 11.2% and 20.2%, respectively; the detection rates of mild stress and moderate to extremely severe stress were 9.3% and 10.2%, respectively. Avoidance and resignation coping were positively correlated with the overall scores of general distress which represents the total scores of the Depression Anxiety Stress Scale (r = 0.171, 0.475, P < 0.01). Multiple linear stepwise regression results showed that husband-wife relationships and avoidance and resignation coping strategies were the main factors predicting general distress levels.

Conclusions

Patients with intrauterine adhesions have psychological distress in a certain extent. Target interventions should be taken to improve the mental health level of patients.

Selected to survive and kill: Tityus serrulatus, the Brazilian yellow scorpion

Annually, more than 1.2 million scorpion stings and more than 3,000 deaths occur worldwide. Tityus serrulatus Lutz and Mello, 1922 (Scorpiones, Buthidae) is the most medically relevant species in Brazil where it is spreading rapidly and causing over 90,000 cases of envenomation yearly. We monitored T. serrulatus longevity and ability to reproduce under conditions of food and/or water deprivation. We found that T. serrulatus is highly tolerant to food deprivation, with individuals enduring up to 400 days without food. On the other hand, access to water played a pivotal role in T. serrulatus survival. Food and water deprived scorpions showed weight reduction. Reproduction occurred throughout the year for food-deprived scorpions and controls, but not in the water-deprived groups. Remarkably, food-deprived animals were able to give birth after 209 days of starvation. Tityus serrulatus resistance to food and water deprivation is likely to be an additional factor underlying this species' geographic expansion and the difficulties encountered in controlling it.

Chlorotoxin peptide-functionalized polyethylenimine-entrapped gold nanoparticles for glioma SPECT/CT imaging and radionuclide therapy

BACKGROUND

Malignant glioma is the most common and deadliest brain cancer due to the obstacle from indistinct tumor margins for surgical excision and blood brain barrier (BBB) for chemotherapy. Here, we designed and prepared multifunctional polyethylenimine-entrapped gold nanoparticles (Au PENPs) for targeted SPECT/CT imaging and radionuclide therapy of glioma.

RESULTS

Polyethylenimine was selected as a template for sequential modification with polyethylene glycol (PEG), glioma-specific peptide (chlorotoxin, CTX) and 3-(4-hydroxyphenyl)propionic acid-OSu (HPAO), and were then used to entrap gold nanoparticles (Au NPs). After 131I radiolabeling via HPAO, the 131I-labeded CTX-functionalized Au PENPs as a multifunctional glioma-targeting nanoprobe were generated. Before 131I radiolabeling, the CTX-functionalized Au PENPs exhibited a uniform size distribution, favorable X-ray attenuation property, desired water solubility, and cytocompatibility in the given Au concentration range. The 131I-labeled CTX-functionalized Au PENPs showed high radiochemical purity and stability, and could be used as a nanoprobe for the targeted SPECT/CT imaging and radionuclide therapy of glioma cells in vitro and in vivo in a subcutaneous tumor model. Owing to the unique biological properties of CTX, the developed nanoprobe was able to cross the BBB and specifically target glioma cells in a rat intracranial glioma model.

CONCLUSIONS

Our results indicated that the formed nanosystem had the significant potential to be applied for glioma targeted diagnosis and therapy.

Second Dose of Scorpion Antivenom in Children with Indian Red Scorpion (Mesobuthus tamulus) Sting Envenomation

OBJECTIVE

To study the effect of the second dose of scorpion antivenom in children with non-resolving or worsening scorpion sting envenomation.

METHODS

72 children aged ≤12 years with scorpion sting envenomation grade 2 and above were enrolled. 61 received the first dose of three vials of antivenom at admission (group A). Children with persistent/worsening envenomation at 6 hours received the second dose (group B). The time required for resolution of autonomic symptoms, myocardial dysfunction, predictors of the second dose and side effects were studied.

RESULTS

The mean time taken for resolution of autonomic symptoms were similar in GroupA and B (4.1 vs. 5.3 hours, P=0.452), and of myocardial dysfunction was shorter in Group A (10.8 vs. 37.6 hours, P=0.019). On regression analysis, abnormal echocardiography at admission was found to be a significant predictor of the second dose (OR=27.6, 95% CI, 4.7-162.5; P=<0.001).

CONCLUSION

Children with severe scorpion sting envenomation with abnormal echocardiography may require a higher dose of scorpion antivenom.

Aspidosperma pyrifolium Has Anti-Inflammatory Properties: An Experimental Study in Mice with Peritonitis Induced by Tityus serrulatus Venom or Carrageenan

Scorpions of the genus Tityus are responsible for the majority of envenomation in Brazil, the Tityus serrulatus species being the most common and dangerous in South America. In this approach, we have investigated the ability of the aqueous extract from the leaves of Aspidosperma pyrifolium in reducing carrageenan-induced inflammation and the inflammation induced by T. serrulatus envenomation in mice. We also evaluated the cytotoxic effects of this extract, using the 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl-2H-tetrazolium (MTT) assay and the results revealed that the extract is safe. Analysis by High Performance Liquid Chromatography coupled with Diode Array Detector (HPLC-DAD) and Liquid Chromatography Coupled with Mass Spectrometry with Diode Array Detection (LC-DAD-MS) showed one major chemical component, the flavonoid rutin and phenolics compounds. For in vivo studies in carrageenan-induced peritonitis model, mice received extracts, dexamethasone, rutin or saline, before administration of carrageenan. For venom-induced inflammation model, animals received T. serrulatus venom and were, simultaneously, treated with extracts, antivenom, rutin or saline. The extract and rutin showed a reduction in the cell migration into the peritoneal cavity, and in the same way the envenomated animals also showed reduction of edema, inflammatory cell infiltration and vasodilation in lungs. This is an original study revealing the potential action of A. pyrifolium against inflammation caused by Tityus serrulatus venom and carrageenan, revealing that this extract and its bioactive molecules, specifically rutin, may present potential anti-inflammatory application.

Electrophysiological Characterization of the Antarease Metalloprotease from Tityus serrulatus Venom

Scorpions are among the oldest venomous living organisms and the family Buthidae is the largest and most medically relevant one. Scorpion venoms include many toxic peptides, but recently, a metalloprotease from Tityus serrulatus called antarease was reported to be capable of cleaving VAMP2, a protein involved in the neuroparalytic syndromes of tetanus and botulism. We have produced antarease and an inactive metalloprotease mutant in a recombinant form and analyzed their enzymatic activity on recombinant VAMP2 in vitro and on mammalian and insect neuromuscular junction. The purified recombinant antarease paralyzed the neuromuscular junctions of mice and of Drosophila melanogaster whilst the mutant was inactive. We were unable to demonstrate any cleavage of VAMP2 under conditions which leads to VAMP proteolysis by botulinum neurotoxin type B. Antarease caused a reduced release probability, mainly due to defects upstream of the synaptic vesicles fusion process. Paired pulse experiments indicate that antarease might proteolytically inactivate a voltage-gated calcium channel.

[Relationships between venomous function and innate immune function]

Venomous function is investigated in relation to innate immune function in two cases selected from scorpion venom and serpent venom. In the first case, structural analysis of scorpion toxins and defensins reveals a close interrelation between both functions (toxic and innate immune system function). In the second case, structural and functional studies of natural inhibitors of toxic snake venom phospholipases A2 reveal homology with components of the innate immune system, leading to a similar conclusion. Although there is a clear functional distinction between neurotoxins, which act by targeting membrane ion channels, and the circulating defensins which protect the organism from pathogens, the scorpion short toxins and defensins share a common protein folding scaffold with a conserved cysteine-stabilized alpha-beta motif of three disulfide bridges linking a short alpha helix and an antiparallel beta sheet. Genomic analysis suggests that these proteins share a common ancestor (long venom toxins were separated from an early gene family which gave rise to separate short toxin and defensin families). Furthermore, a scorpion toxin has been experimentally synthetized from an insect defensin, and an antibacterial scorpion peptide, androctonin (whose structure is similar to that of a cone snail venom toxin), was shown to have a similar high affinity for the postsynaptic acetylcholine receptor of Torpedo sp. Natural inhibitors of phospholipase A2 found in the blood of snakes are associated with the resistance of venomous snakes to their own highly neurotoxic venom proteins. Three classes of phospholipases A2 inhibitors (PLI-α, PLI-β, PLI-γ) have been identified. These inhibitors display diverse structural motifs related to innate immune proteins including carbohydrate recognition domains (CRD), leucine rich repeat domains (found in Toll-like receptors) and three finger domains, which clearly differentiate them from components of the adaptive immune system. Thus, in structure, function and phylogeny, venomous function in both vertebrates and invertebrates are clearly interrelated with innate immune function.

Emergent management of scorpion sting

Scorpionism (syndrome of scorpion stings) is an important public health problem in many regions of the world, not only in tropics and subtropics. As scorpions may be unintentionally transported to any place in the world and keeping scorpions as pets is becoming more popular, scorpion stings occur also in Poland. Therefore, health professionals should have the knowledge on the management of scorpion stings. This article discusses a case who was stung by scorpion and proposes an algorithm of management with such patients.

Treatment of scorpion envenoming syndrome -- need for scientific magnanimity

Scorpion envenoming syndrome results in a severe autonomic storm with a massive release of catecholamines, increased levels of angiotensin II, an increase in glucagon, cortisol, thyroid hormones; either suppressed insulin levels or hyperinsulinaemia (insulin resistance), hyperglycaemia; increased circulating free fatty acid levels. These hormonal alterations could be responsible for the pathogenesis of a variety of clinical manifestations. Under these conditions, scorpion envenoming syndrome with myocardial damage, cardiovascular disturbances, peripheral circulatory failure, respiratory and cardiac pulmonary oedema, and many other clinical manifestations resulting in a syndrome of fuel-energy deficits and an inability to use the existing metabolic substrates by vital organs causing multisystem organ failure and death. Based on animal experiments in which insulin administration reversed the metabolic and ECG changes induced by scorpion envenoming and treating the poisonous scorpion sting victims with insulin, we consider that insulin has a primary metabolic role in preventing and reversing the cardiovascular, haemodynamic, and neurological manifestations and pulmonary oedema induced by scorpion envenoming. Administration of insulin-glucose infusion to scorpion sting victims appears to be the physiological basis for the control of the metabolic response when that has become a determinant to survival. The mordality of treatment is continuous infusion of regular crystalline insulin at the rate of 0.3 U/g glucose and glucose at the rate of 0.1g/kg body weight/hour, with supplementation of potassium as needed and maintenance of fluid, electrolytes and acid-base balance is required. This treatment should be given at the earliest on admission and continued for the next 48-72 hours. Antiscorpion serum could also be given independently or along with insulin-glucose infusion.

Scorpion sting: update

Scorpion envenomation is an important public health hazard in tropical and sub-tropical regions. Envenomation by scorpions can result in a wide range of clinical effects, including, cardiotoxicity, neurotoxicity and respiratory dysfunction. Out of 1500 scorpion species known to exist, about 30 are of medical importance. Although a variety of different scorpion species exist, majority of them produce similar cardiovascular effects. Scientists and clinicians have studied patho-physiology of scorpion envenomation by critical observations of clinical, neurotransmitters studies, radioisotope studies, echocardiography and haemodynamic patterns. Regimen including scorpion antivenom, vasodilators, intensive care management have been tried to alleviate the systemic effects of envenoming. In spite of advances in patho-physiology and therapy the mortality remains high in rural areas due to lack of access to medical facilities, moreover the medical attendee from developing tropical countries may not be aware of the advances in the treatment of scorpion sting. Since the advent of scorpion Antivenom, vasodilators, dobutamine and intensive care facilities, the fatality due to severe scorpion sting has been significantly reduced in areas where these treatment modalities are used.

Efficacy and safety of scorpion antivenom plus prazosin compared with prazosin alone for venomous scorpion (Mesobuthus tamulus) sting: randomised open label clinical trial

OBJECTIVE

Envenomation by Mesobuthus tamulus scorpion sting can result in serious cardiovascular effects. Scorpion antivenom is a specific treatment for scorpion sting. Evidence for the benefit of scorpion antivenom and its efficacy compared with that of commonly used vasodilators, such as prazosin, is scarce. We assessed the efficacy of prazosin combined with scorpion antivenom, compared with prazosin alone, in individuals with autonomic storm caused by scorpion sting.

DESIGN

Prospective, open label randomised controlled trial.

SETTING

General hospital inpatients (Bawaskar Hospital and Research Centre Mahad Dist-Raigad Maharashtra, India).

PARTICIPANTS

Seventy patients with grade 2 scorpion envenomation, older than six months, with no cardiorespiratory or central nervous system abnormalities.

INTERVENTION

Scorpion antivenom plus prazosin (n=35) or prazosin alone (n=35) assigned by block randomisation. Treatment was not masked. Analysis was by intention to treat.

MAIN OUTCOME MEASURES

The primary end point was the proportion of patients achieving resolution of the clinical syndrome (sweating, salivation, cool extremities, priapism, hypertension or hypotension, tachycardia) 10 hours after administration of study drugs. Secondary end points were time required for complete resolution of clinical syndrome, prevention of deterioration to higher grade, doses of prazosin required overall and within 10 hours, and adverse events. The study protocol was approved by the independent ethics committee of Mumbai.

RESULTS

Mean (SD) recovery times in hours for the prazosin plus scorpion antivenom group compared with the prazosin alone groups were: sweating 3 (1.1) v 6.6 (2.6); salivation 1.9 (0.9) v 3 (1.9); priapism 4.7 (1.5) v 9.4 (1.5). Mean (SD) doses of prazosin in the groups were 2 (2.3) and 4 (3.5), respectively. 32 patients (91.4%, 95% confidence interval 76.9% to 97.8%) in the prazosin plus antivenom group showed complete resolution of the clinical syndrome within 10 hours of administration of treatment compared with eight patients in the prazosin group (22.9%, 11.8% to 39.3%). Patients from the antivenom plus prazosin group recovered earlier (mean 8 hours, 95% CI 6.5 to 9.5) than those in the control group (17.7 hours, 15.4 to 19.9; mean difference -9.7 hours, -6.9 to -12.4). The number of patients whose condition deteriorated to a higher grade was similar in both groups (antivenom plus prazosin four of 35, prazosin alone five of 35). Hypotension was reported in fewer patients in the antivenom plus prazosin group (12 of 35, 34.3%) than in the prazosin group (19 of 35, 54.3%), but the difference was not statistically significant. No difference was noted in change in blood pressure and pulse rate over time between two groups.

CONCLUSION

Recovery from scorpion sting is hastened by simultaneous administration of scorpion antivenom plus prazosin compared with prazosin alone.

TRIAL REGISTRATION NUMBER

CTRI/2010/091/000584 (Clinical Trials Registry India).

[Scorpion envenomation treated at Beni Mellal Provincial Hospital in Morocco]

The Beni Mellal province has one of the highest incidences of scorpion envenomation in Morocco. The purpose of this retrospective study was to report and analyze data recorded in scorpion envenomation victims admitted to the intensive care department of the Beni Mellal Provincial Hospital. A total of 63 patients were admitted in 2005. Most stings occurred during summer mainly in June and July. Most (60.3%) occurred at night between 6 p.m. and 6 a.m. Most patients were children younger than 16 years (mean, 10.2 +/- 12.9 years). At the time of admission, general manifestations of envenomation were present in 72.6% of patients and life-threatening symptoms were observed in 27.4%. Therapy consisted of symptomatic treatment and in-hospital mortality was 28.6%. There was not a significant difference in mortality in function of age or severity of manifestations at the time of admission.

Role of prazosin on cardiovascular manifestations and pulmonary edema following severe scorpion stings in Saudi Arabia

We report the ameliorating effects of prazosin on the cardiovascular CV manifestations and pulmonary edema PE after treatment with antivenom AV failed to improve the conditions of scorpion stung patients. Three cases of scorpion envenoming, 2 children and one adult, were received at the Accident and Emergency Department of Al-Birk Hospital, Asir Region, Saudi Arabia. They presented to the hospital late with features of severe perspiration, tachypnea, restlessness, drooling of saliva, priapism, sinus tachycardia, PE, and shock like syndrome. When polyvalent scorpion PVS AV and intensive supportive treatment failed to show any improvement, prazosin was administered to the patients, which resulted in dramatic improvement in the conditions of the patients. We conclude that PVS AV may not be beneficial in all cases of scorpion envenomation, and prazosin may be an effective alternative for treating scorpion sting cases with CV manifestations and PE.

Degranulation of mast cells and histamine release involved in rat pain-related behaviors and edema induced by scorpion Buthus martensi Karch venom

In the present study, it was investigated whether the degranulation of mast cells and histamine release were involved in rat pain-related behaviors and edema induced by the venom of scorpion Buthus martensi Karch (BmK) or not. It was found that the obvious degranulation of mast cells could be triggered in rat hindpaw skin by BmK venom. The chronic degranulation of mast cells using compound 48/80 relieved the spontaneous nociceptive responses, the primary thermal and bilateral mechanical hyperalgesia and the rat paw edema, as well as partially reduced c-Fos expression in superficial layers (laminae I-II) of bilateral spinal cord induced by BmK venom. In addition, individual peripheral co-administration of either 100 nmol chlorpheniramine or 100 nmol pyrilamine (histamine H(1) receptor antagonist) or 500 nmol cimetidine (histamine H(2) receptor antagonist) and BmK venom suppressed the spontaneous nociceptive responses, partially the primary thermal and bilateral mechanical hyperalgesia and rat paw edema induced by BmK venom. Thus, these results suggest that the peripheral cellular incidents of mast cells degranulation and histamine release are involved in BmK venom-induced pain-related behaviors and inflammation.

Margatoxin inhibits VEGF-induced hyperpolarization, proliferation and nitric oxide production of human endothelial cells

BACKGROUND

Vascular endothelial growth factor (VEGF) induces proliferation of endothelial cells (EC) in vitro and angiogenesis in vivo. Furthermore, a role of VEGF in K(+) channel, nitric oxide (NO) and Ca(2+) signaling was reported. We examined whether the K(+) channel blocker margatoxin (MTX) influences VEGF-induced signaling in human EC.

METHODS

Fluorescence imaging was used to analyze changes in the membrane potential (DiBAC), intracellular Ca(2+) (FURA-2) and NO (DAF) levels in cultured human EC derived from human umbilical vein EC (HUVEC). Proliferation of HUVEC was examined by cell counts (CC) and [(3)H]-thymidine incorporation (TI).

RESULTS

VEGF (5--50 ng/ml) caused a dose-dependent hyperpolarization of EC, with a maximum at 30 ng/ml (n=30, p<0.05). This effect was completely blocked by MTX (5 micromol/l). VEGF caused an increase in transmembrane Ca(2+) influx (n=30, p<0.05) that was sensitive to MTX and the blocker of transmembrane Ca(2+) entry 2-aminoethoxydiphenyl borate (APB, 100 micromol/l). VEGF-induced NO production was significantly reduced by MTX, APB and a reduction in extracellular Ca(2+) (n=30, p<0.05). HUVEC proliferation, examined by CC and TI, was significantly increased by VEGF and inhibited by MTX (CC: -58%, TI --121%); APB (CC --99%, TI--187%); N-monomethyl-L-arginine (300 micromol/l: CC: -86%, TI --164%).

CONCLUSIONS

VEGF caused an MTX-sensitive hyperpolarization which results in an increased transmembrane Ca(2+) entry that is responsible for the effects on endothelial proliferation and NO production.

Biophysical and pharmacological properties of the voltage-gated potassium current of human pancreatic beta-cells

Voltage-gated potassium (Kv) currents of human pancreatic islet cells were studied by whole-cell patch clamp recording. On average, 75% of the cells tested were identified as beta-cells by single cell, post-recording RT-PCR for insulin mRNA. In most cells, the dominant Kv current was a delayed rectifier. The delayed rectifier activated at potentials above -20 mV and had a V(1/2) for activation of -5.3 mV. Onset of inactivation was slow for a major component (tau = 3.2 s at +20 mV) observed in all cells; a smaller component (tau = 0.30 s) with an amplitude of approximately 25% was seen in some cells. Recovery from inactivation had a tau of 2.5 s at -80 mV and steady-state inactivation had a V(1/2) of -39 mV. In 12% of cells (21/182) a low-threshold, transient Kv current (A-current) was present. The A-current activated at membrane potentials above -40 mV, inactivated with a time constant of 18.5 ms at -20 mV, and had a V(1/2) for steady-state inactivation of -52 mV. TEA inhibited total Kv current with an IC50 = 0.54 mm and PAC, a disubstituted cyclohexyl Kv channel inhibitor, inhibited with an IC50 = 0.57 microm. The total Kv current was insensitive to margatoxin (100 nm), agitoxin-2 (50 nm), kaliotoxin (50 nm) and ShK (50 nm). Hanatoxin (100 nm) inhibited total Kv current by 65% at +20 mV. Taken together, these data provide evidence of at least two distinct types of Kv channels in human pancreatic beta-cells and suggest that more than one type of Kv channel may be involved in the regulation of glucose-dependent insulin secretion.

Increase of delayed rectifier potassium currents in large aspiny neurons in the neostriatum following transient forebrain ischemia

Large aspiny (LA) neurons in the neostriatum are resistant to cerebral ischemia whereas spiny neurons are highly vulnerable to the same insult. Excitotoxicity has been implicated as the major cause of neuronal damage after ischemia. Voltage-dependent potassium currents play important roles in controlling neuronal excitability and therefore influence the ischemic outcome. To reveal the ionic mechanisms underlying the ischemia-resistance, the delayed rectifier potassium currents (Ik) in LA neurons were studied before and at different intervals after transient forebrain ischemia using brain slices and acute dissociation preparations. The current density of Ik increased significantly 24 h after ischemia and returned to control levels 72 h following reperfusion. Among currents contributing to Ik, the margatoxin-sensitive currents increased 24 h after ischemia while the KCNQ/M current remained unchanged after ischemia. Activation of protein kinase A (PKA) down-regulated Ik in both control and ischemic LA neurons, whereas inhibition of PKA only up-regulated Ik and margatoxin-sensitive currents 72 h after ischemia, indicating an active PKA regulation on Ik at this time. Protein tyrosine kinases had a tonic inhibition on Ik to a similar extent before and after ischemia. Compared with that of control neurons, the spike width was significantly shortened 24 h after ischemia due to facilitated repolarization, which could be reversed by blocking margatoxin-sensitive currents. The increase of Ik in LA neurons might be one of the protective mechanisms against ischemic insult.

Peripheral and spinal mechanisms of antinociceptive action of lumiracoxib

The possible participation of the nitric oxide (NO)-cyclic GMP-K(+) channel pathway, serotonergic or opioidergic system on lumiracoxib-induced local or intrathecal antinociception was assessed in the formalin test. Local or intrathecal administration of lumiracoxib dose-dependently produced antinociception in the second phase of the test. Moreover, local or intrathecal pretreatment with N(G)-L-nitro-arginine methyl ester (L-NAME, NO synthesis inhibitor), 1H-(1,2,4)-oxadiazolo(4,2-a)quinoxalin-1-one (ODQ, guanylyl cyclase inhibitor), glibenclamide (ATP-sensitive K(+) channel blocker), charybdotoxin and apamin (large- and small-conductance Ca(2+)-activated-K(+) channel blockers, respectively) or margatoxin (voltage-dependent K(+) channel blocker), but not N(G)-D-nitro-arginine methyl ester (D-NAME) or vehicle, significantly prevented lumiracoxib-induced antinociception. The intrathecal injection of methiothepin (serotonin receptor antagonist) reduced lumiracoxib-induced intrathecal antinociception. Local peripheral or intrathecal naloxone did not modify either local or intrathecal lumiracoxib-induced antinociception. Results suggest that lumiracoxib activates the NO-cyclic GMP-K(+) channels to produce local and intrathecal antinociception. Data also suggest that lumiracoxib activates the intrathecal serotonergic system, but not opioid receptors either at peripheral or spinal sites.

A novel potassium channel in lymphocyte mitochondria

The margatoxin-sensitive Kv1.3 is the major potassium channel in the plasma membrane of T lymphocytes. Electron microscopy, patch clamp, and immunological studies identified the potassium channel Kv1.3, thought to be localized exclusively in the cell membrane, in the inner mitochondrial membrane of T lymphocytes. Patch clamp of mitoplasts and mitochondrial membrane potential measurements disclose the functional expression of a mitochondrial margatoxin-sensitive potassium channel. To identify unambiguously the mitochondrial localization of Kv1.3, we employed a genetic model and stably transfected CTLL-2 cells, which are genetically deficient for this channel, with Kv1.3. Mitochondria isolated from Kv1.3-reconstituted CTLL-2 expressed the channel protein and displayed an activity, which was identical to that observed in Jurkat mitochondria, whereas mitochondria of mock-transfected cells lacked a channel with the characteristics of Kv1.3. Our data provide the first molecular identification of a mitochondrial potassium conductance.

Dantrolene protects hippocampal cells from damage induced by TsTX, an alpha-scorpion toxin from Tityus serrulatus

We examined the effects of dantrolene, an inhibitor of intracellular calcium release, on alterations associated with the intrahippocampal injection of the TsTX scorpion toxin. Male Wistar rats (230-250 g) were injected with Ringer solution (1 microl; n = 6); TsTX toxin (1 microg/microl; n = 8); and dantrolene (10.0 mg/kg) plus TsTX toxin (1 microg/microl; n = 6). After injection, electroencephalographic (EEG) recordings and observation of animals behaviour were performed continuously for 4 h. One week later, animals were submitted to histopathological analysis. TsTX caused electrographic seizure expressed by moderate or intense discharges and neuronal loss in hippocampal areas in all injected animals (n = 8). Dantrolene reduced the effect of TsTX. Thus, 67% of rats (four out of six) treated with toxin and dantrolene had electrographic convulsions, but only for 30 min after injection and none of them presented neuronal damage. Dantrolene or Ringer had no effects on the EEG.

Volume regulation of mature and immature spermatozoa in a primate model, and possible ion channels involved

BACKGROUND

Human ejaculated sperm undergo volume regulation, and swollen cells fail to penetrate mucus. Study of an infertile mouse model indicates maturation of volume regulation mechanism in the epididymis.

METHODS

Sperm from the ejaculate and three regions of the epididymis of the cynomolgus monkey (Macaca fascicularis) were dispersed in BWW medium and changes in the cell volume and kinematics, and their responses to ion channel blockers, were monitored by flow cytometry and motion analysis.

RESULTS

Initially swollen cauda epididymidal spermatozoa regained their original volume within 20 min, but not in the presence of 0.25 mM quinine. Corpus epididymidal spermatozoa underwent such regulatory volume decrease (RVD) to a lesser extent, with a similar response to quinine. Caput sperm showed no swelling throughout incubation. The chloride channel inhibitor NPPB also caused swelling of cauda spermatozoa and both quinine and NPPB decreased the efficiency of forward progression. RVD of ejaculated spermatozoa was inhibited by the K+ channel blockers quinine and 4-aminopyridine (4-AP) but not by tetraethylammonium, Ba2+ or Gd3+, or the specific potassium channel blockers charybdotoxin, margatoxin, dendrotoxin, apamin, glybenclamide or clofilium. Quinine and 4-AP also altered ejaculated sperm kinematics as reported in human ejaculated spermatozoa.

CONCLUSIONS

Quinine- and 4-AP-sensitive (implying K+) and NPPB-sensitive (implying Cl-) channels are involved in RVD of primate sperm, which develop this volume regulatory ability in the epididymis.

Kv1.3 channel gene-targeted deletion produces "Super-Smeller Mice" with altered glomeruli, interacting scaffolding proteins, and biophysics

Mice with gene-targeted deletion of the Kv1.3 channel were generated to study its role in olfactory function. Potassium currents in olfactory bulb mitral cells from Kv1.3 null mice have slow inactivation kinetics, a modified voltage dependence, and a dampened C-type inactivation and fail to be modulated by activators of receptor tyrosine signaling cascades. Kv1.3 deletion increases expression of scaffolding proteins that normally regulate the channel through protein-protein interactions. Kv1.3-/- mice have a 1,000- to 10,000-fold lower threshold for detection of odors and an increased ability to discriminate between odorants. In accordance with this heightened sense of smell, Kv1.3-/- mice have glomeruli or olfactory coding units that are smaller and more numerous than those of wild-type mice. These data suggest that Kv1.3 plays a far more reaching role in signal transduction, development, and olfactory coding than that of the classically defined role of a potassium channel-to shape excitability by influencing membrane potential.

[National strategy in the battle against scorpion stings and envenomations. Application and evaluation]

Scorpion stings represent the first cause of poisoning with an incidence of 30 to 50% of all declared cases in the Centre Anti Poison of Morocco (CAPM). Aware of this increasing problem, the CAPM paid special attention to this pathology. Thanks to its retrospective and prospective studies, the scorpion species mapping has been determined as well as the demographic features of stung patients, the nature and the chronology of clinical events in scorpion envenimation, and the epidemiological, clinical and therapeutical factors of severity. On this basis, the CAPM worked out a national strategy to struggle against scorpion stings whose aim was to decrease the morbidity and mortality caused by stings of scorpion as well as to rationalise economic expenses. The components of this strategy were based on the training of the medical and paramedical staff, on information, education, communication involving different sectors, on identification of needs and on follow-up and assessment. A nationwide campaign was implemented to change the population and health-care staff's behaviour regarding this pathology. Its evaluation permitted to improve the compilation of cases with census of 14104 cases, to reduce lethality rate and to rationalise expenses while banishing some medicines and avoiding useless hospitalization.

Clinical profile of severe scorpion envenomation in children at rural setting

he present study is an attempt to evaluate the clinical manifestations of severe scorpion sting in children and their management at a rural setting. Twelve patients with severe scorpion sting referred from primary health center are presented in this report. Eight children had pulmonary edema and hypotension; two had pulmonary edema and hypertension while one each presented with hypertension and tachycardia in isolation. Oral prazosin, dobutamine infusion and sodium nitroprusside drip (SNP) were used as therapeutic options based on the symptomatology. Two children died of massive pulmonary edema despite use of SNP and dopamine drip. Anti scorpion venom did not prevent the cardiovascular manifestations of severe scorpion sting. Early administration of prazosin alleviated the severity of scorpion envenomation