Evaluation of chemosterility effect of different insect growth regulators on Bactrocera zonata population.

The indiscriminate application of synthetic pesticides on horticultural plants for the management of Bactrocera zonata has both economic and environmental implications due to the biomagnification of harmful residues in humans via the food chain. This necessitates the use of some eco-friendly control measures such as insect growth regulators (IGRs) as an alternative. A laboratory experiment was laid out to determine the potential chemosterilant effect of five IGRs including pyriproxyfen, novaluron, lufenuron, buprofezin, and flubendiamide at six different concentrations on B. zonata after treating adult diet. Using the oral bioassay, B. zonata were fed on IGRs impregnated diet (50-300 ppm/5 mL diet) which was replaced with the normal diet after 24 h of feeding. Ten pairs of B. zonata were placed in a separate plastic cage accommodating an ovipositor attractant guava for eggs collection and calculation. An analysis of the result revealed that fecundity and hatchability were higher at a low dose and vice versa. Lufenuron at 300 ppm/5 mL of diet significantly decreased the fecundity rate (31.1%) as compared to pyriproxyfen, novaluron, buprofezin and flubendiamide, which had 39.3%, 39.3%, 43.8%, and 47.5%, respectively. The lowest hatchability (19.9%) was noted in lufenuron treated diet followed by pyriproxyfen, novaluron, buprofezin, and flubendiamide, which had 22.1%, 25.0%, 30.9%, and 31.6%, respectively. Furthermore, in a population of crosses between the lufenuron treated male and female, a significant decrease in fecundity (45.5%) and hatchability (51.7%) was noted as compared to other IGRs. Overall, this study identified the chemosterilant potential of lufenuron on the population of B. zonata which can be integrated for its management strategy.

Effects of four chemosterilants on Bactrocera tau.

Bactrocera tau (Walker) is a fly pest species mainly distributed in Southeast Asia and the South Pacific; it causes substantial ecological and economic issues because of its destructiveness and rapid reproduction. Chemical sterilization technology can reduce the use of insecticides and is widely applied for insect pest control. In this study, the sterilization efficacy of varying concentrations of four chemosterilants, namely, hexamethylphosphoramide (HMPA), CSII Aqua, 5-fluorouracil (5-FU), and colchicine, on adult pumpkin flies was investigated. The results indicated that a solution of 0.03% HMPA had the highest sterilization efficacy. When the number of sterile males was equal to or exceeded 20 times that of untreated males, the hatching rate of offspring eggs was less than 10%. Chemosterilant treatment significantly altered the levels of acid phosphatase (ACP), alkaline phosphatase (AKP), and B. tau vitellogenin (BtVg); these substances have an important impact on reproductive development. The treatment also decreased the size of the reproductive organs (i.e., testes and ovaries). Our results suggest that 0.03% HMPA has unique sterilization properties and may represent a new chemical agent for the control of B. tau populations in agricultural settings.

Nephrotoxicity evaluation of 3-monochloropropane-1,2-diol exposure in Sprague-Dawley rats using data-independent acquisition-based quantitative proteomics analysis.

3-Monochloropropane-1,2-diol (3-MCPD), as a heat-induced food process contaminant, possesses strongly toxic effect on kidney. The present study focuses on characterizing the proteome and clarifying the underlying molecular regulatory mechanisms in a model of kidney injury in rats treated with 3-MCPD. Data-independent acquisition (DIA)-mass spectrometry (MS) based proteomics was used to identify dysregulated proteins in kidney tissues of Sprague-Dawley (SD) rats treated with 30 mg/kg/day 3-MCPD by gavage for 28 days. It was found that a total of 975 proteins were deregulated after 3-MCPD treatment. Bioinformatic analyses revealed that several enzymes related to the metabolisms of amino acid, lipid and carbohydrate in endogenous metabolism were altered in response to 3-MCPD treatment. Moreover, some proteins involved in these pathways were also changed, mainly including oxidative stress, oxidative phosphorylation, apoptosis and autophagy. Our study unravels the vital roles of loss of mitochondrial homeostasis and function and cell death pathways in the development of renal damage induced by 3-MCPD, which provides further valuable insights into the initiation and resolution of 3-MCPD nephrotoxicity. The proposed DIA-MS workflow not only provides a choice for proteomic analysis in toxicological research, but also provides a more comprehensive understanding of the molecular mechanisms of nephrotoxicity induced by toxins.

Apoptosis is induced by sub-acute exposure to 3-MCPD and glycidol on Wistar Albino rat brain cells.

3-chloropropane-1,2-diol (3-MCPD) and its toxic metabolite glycidol were classified by the International Agency for Research on Cancer (IARC) as belonging to group 2B and 2A for humans. This study aimed to determine the sub-acute toxicity of these agents. Rats were exposed to 3-MCPD at 0.87 and 10 mg/kg/bw and glycidol (2,4 and 37,5 mg/kg/bw) for 90 days. miR-21 gene expression levels significantly decreased in all group's cerebellar tissues compared with control. Exposure to 10 mg/kg/bw 3-MCPD showed significant increases in PTEN in brain as compared to control group. The Akt gen expressions were significantly decreased in 3-MCPD and glycidol groups when compared to control group brains. Additionally, Caspase 3 and AIF immunopositivity significantly increased in 3-MCPD high dose and glycidol high dose groups in cerebellum granular layers compared to control. The results of the present study conclude that 3-MCPD and glycidol can induce apoptosis in rat brain tissue.

Efficacy of Azadirachta indica (Neem) leaf extract and hypertonic saline solution as intratesticular chemical sterilizing agents in dogs / Eficácia do extrato de folha de Azadirachta indica (Neem) e solução salina hipertônica como agente químico esterilizante intratesticular em cães

Castration refers to induced sterility via physical, chemical, or hormonal methods. Chemical castration is an efficient and reliable technique in contrast to other sterilization procedures as it is less painful to physical methods and cost­effective to hormonal methods. Azadirachta indica (neem), is a charismatic plant as its leaves possess anti­inflammatory, anti­microbial, and anti­androgenic chattels. To abate the escalating human population in South Asia, neem oil and neem leaf extract have been effectively used as a contraceptive agent. The key determinant of the current study was to evaluate Neem as a chemical sterilizing agent, (either necrotic or apoptotic), in dogs injected intratesticular in comparison to a hypertonic saline solution. Pre­ and post­injection testicular width size and blood samples for serum testosterone levels were collected on alternative days. Results disclosed substantial changes in testicular width size, histopathological profile, and serum testosterone level. A non­significant (P > 0.05) pre­injection testicular width readings in contrast to a significant increase (P < 0.05) three days post­injection was noted in all the competitive groups. The mean values recorded for testicular width size at the end of the trial study via neem leaf extract, 30% HSS and, control groups were 27.7362 ± 2.3315mm, 30.9594 ± 4.6861mm, and 24.5023 ± 2.5387mm, respectively. A declining trend, regarding serum testosterone level being statistically significant (P < 0.05) was recorded in treated groups (A, B) in contrast to the control group (C) as the values were 1.5357 ± 0.7819ng, 1.2669 ± 0.9095ng, and 2.4517 ± 0.1827ng in groups A, B, and C, respectively. Histopathological findings advocated the presence of apoptotic bodies in the neem treated group whereas the presence of degenerated interstitial cells, necrosed seminiferous tubules, damaged germinal epithelium, and ceased spermatogenesis was also studied in both competitive groups. Thus, the apoptotic effect and anti­inflammatory property of neem leaf extract resulted in less painful castration and verified Azadirachta indica as a better substitute for chemical castration in contrast to hypertonic saline solution.(AU)

A castração consiste na indução da esterilidade por meio físico, químico ou hormonal. A castração química é uma técnica eficiente e confiável, em contraste com outros procedimentos de esterilização, pois é menos dolorosa para os métodos físicos e econômicos para os métodos hormonais. Azadirachta indica (neem), é uma planta carismática, pois possui folhas anti­inflamatórias, antimicrobianas e antiandrogênicas. Para diminuir a crescente população humana no sul da Ásia, o óleo de nim e o extrato de folhas de nim têm sido efetivamente usados como agente contraceptivo. O principal determinante deste estudo atual foi avaliar o Neem como um agente esterilizante químico (necrótico ou apoptótico) em cães injetados intratesticularmente em comparação com uma solução salina hipertônica. O tamanho da largura testicular pré e pós­injeção e as amostras de sangue para os níveis séricos de testosterona foram colhidas em dias alternados. Os resultados obtidos revelaram alterações substanciais no tamanho da largura testicular, perfil histopatológico e nível sérico de testosterona. Observou­se uma leitura não significativa (P> 0,05) da largura testicular da pré­injeção, em contraste com um aumento significativo (P <0,05) três dias após a injeção em todos os grupos competitivos.Os valores médios registrados para o tamanho da largura testicular no final do estudo via extrato de folhas de nim,HSS a 30% e grupos controle foram 27,7362 ± 2,3315 mm, 30,9594 ± 4,6861 mm e 24,5023 ± 2,5387 mm, respectivamente.Uma tendência decrescente, com relação ao nível sérico de testosterona sendo estatisticamente significante (P <0,05), foi registrada nos grupos tratados (A, B), em contraste com o grupo controle (C), pois os valores eram 1,5357 ± 0,7819ng, 1,2669 ± 0,9095ng e 2,4517 ± 0,1827ng nos grupos A, B e C, respectivamente. Os achados histopatológicos advogaram a presença de corpos apoptóticos no grupo tratado com nim, enquanto a presença de células intersticiais degeneradas, túbulos seminíferos necrosados, epitélio germinativo danificado e espermatogênese interrompida também foi estudada nos dois grupos competitivos. Assim, o efeito apoptótico e a propriedade anti­inflamatória do extrato de folhas de nim resultaram em uma castração menos dolorosa e confirmaram que a Azadirachta indica foi um melhor substituto para a castração química do que a solução salina hipertônica.(AU)

Necroptosis in 3-chloro-1, 2-propanediol (3-MCPD)-dipalmitate-induced acute kidney injury in vivo and its repression by miR-223-3p.

Fatty acid esters of 3-chloro-1, 2-propanediol (3-MCPD) are a group of processing-induced food contaminants with nephrotoxicity. This study investigated whether and how necroptosis played a role in the nephrotoxic effect of 3-MCPD-dipalmitate (2.5 g/kg BW) in C57 BL/6 mice. The results showed that the principal components in necroptosis pathway including receptor-interacting protein 1 (RIPK1), RIPK3, and mixed lineage kinase domain-like protein (MLKL) were up-regulated in 3-MCPD-dipalmitate-induced acute kidney injury (AKI). Deletion of RIPK3 or MLKL, and inhibition of RIPK1 suppressed AKI. The up-regulation of inflammatory cytokines in the kidney of 3-MCPD-dipalmitate treated mice were attenuated in RIPK3- or MLKL- deficient mice, suggesting a positive feedback loop involving necroptosis and inflammation. The microRNA analysis revealed that 38 known miRNAs and 40 novel miRNAs were differentially expressed (DE) in the kidney treated with 3-MCPD-dipalmitate. Of these miRNAs, miR-223-3p was significantly up-regulated during 3-MCPD-dipalmitate-induced AKI. In cultured mouse proximal tubular cells, a miR-223-3p mimic suppressed RIPK3 expression, which was blocked by miR-223-3p inhibitor. The luciferase reporter assay confirmed that miR-223-3p was able to inhibit RIPK3 expression by targeting the 3' un-translated region of RIPK3. These results suggest that necroptosis contributes to 3-MCPD-dipalmitate-induced acute kidney injury, and that may be attenuated by miR-223-3p.

Contraception in Dogs and Cats.

Although surgical sterilization is the most common approach to reproductive management of dogs and cats in North America and many other places, there is growing interest in nonsurgical and reversible methods. This review summarizes the methods currently available for use as reversible contraception in dogs and cats, along with cautions about reported side effects. The products covered include synthetic steroid hormones, peptide hormone agonists, vaccines, and a barrier method.

Formulation, physical, in vitro and ex vivo evaluation of nanomedicine-based chemosterilant for non-surgical castration of male animals.

The overpopulation of free-roaming companion animals has become the global crisis. The development and application of a suitable, effective, non-surgical approach for animal sterilization would have an enormous advantage over the current surgical method. The main purpose of this study was to develop and evaluate a novel nanomedicine-based chemosterilant for non-surgical castration of male companion animals. In this study, we first sought to investigate the testicular toxicity of different apoptosis-inducing agents. We next synthesized and characterized nano-sized particles which encapsulated the most potent testicular toxicants and evaluated in vitro sterilant properties. Our result showed that doxorubicin exhibited the highest cytotoxic activity against mouse spermatogenic cells. We therefore synthesized and characterized doxorubicin-encapsulated nanoemulsion. The negatively charged particle of doxorubicin-encapsulated nanoemulsion exhibited the anti-proliferative activity towards spermatogetic cells. Apoptosis studies revealed activation of Caspases 3 and 7 as well as annexin V expression. In addition, doxorubicin-encapsulated nanoemulsion exhibited anti-inflammatory activity in lipopolysaccharide-stimulated macrophages. Cell death was observed following treatment of isolated and cultured rat seminiferous tubules with doxorubicin-encapsulated nanoemulsion. In conclusion, nanoemulsion can be a potential carrier for prolonged release and to enhance activity of doxorubicin that may have utility in non-surgical castration of male animals.

Post-operative outcomes of surgical and chemical castration with zinc gluconate in dogs presenting to veterinary field clinics.

The objective of this study was to characterize post-operative outcomes of chemical castration as compared to surgical castration performed by existing municipal field clinics. Fifty-four healthy adult male dogs underwent chemical castration with zinc gluconate solution and 55 healthy adult male dogs underwent surgical castration in veterinary field clinics. Dogs in each group were evaluated for swelling, inflammation, and ulceration (chemical castration) or dehiscence (surgical castration) at Days 3, 7, and 14 following castration. More surgically castrated dogs required medical intervention than chemically castrated dogs (P=0.0328); the number of dogs requiring surgical repair within each group did not differ (P=0.3421). Seven chemically castrated dogs and 22 surgically castrated dogs experienced swelling, inflammation, and/or ulceration; all were managed medically. Two chemically castrated dogs experienced scrotal ulceration requiring surgical castration at Days 3 and 7. One surgically castrated dog experienced partial incisional dehiscence requiring surgical repair at Day 3. Our results suggest that chemical castration of dogs in field clinics is a feasible alternative to surgical castration, but proper follow-up care should be ensured for at least 7days post-procedurally.

Examination of the use of intraovarian administration of CaCl2 and zinc gluconate as potential chemosterilants in Bos indicus heifers.

OBJECTIVE: To investigate if administration of potential chemosterilants by transvaginal, ultrasound-guided intraovarian injection is an alternative to surgical sterilisation. DESIGN: Randomised control study. METHODS: Bos indicus heifers were treated with intraovarian injections of saline (n = 10), CaCl2 (n = 10), zinc gluconate (ZG; n = 10) or a combination of CaCl2 and ZG (CaCl2 + ZG; n = 10). Heifers were exposed to a bull from 82 to 84 days after treatment and slaughtered between 364 and 396 days after treatment. RESULTS: After treatment administration, the concentrations of haptoglobin and anti-Müllerian hormone and the total oocyte counts did not differ (P > 0.150) between treatments. Pain responses were observed in heifers treated with ZG and CaCl2 + ZG but not in heifers treated with saline or CaCl2 . Total ovarian mass at slaughter was less in heifers treated with CaCl2 compared with the other treatments (P < 0.05). Complete regression of one ovary was observed in 40% (4/10) of the heifers treated with CaCl2 . Pregnancies were recorded in ≥ 70% of heifers administered each treatment. CONCLUSION: Treatments used in this study were not able to sterilise most of the B. indicus heifers, but treatment with CaCl2 has the potential to cause complete ovarian atrophy without causing detectable pain.

Biosterilant effects of Bacillus thuringiensis kurstaki HD-73 extract on male Wistar albino rats.

Chemosterilants have long been used in sterilization programs for managing pet, stray, and wild animals but adverse effects such as trauma, incomplete responses to treatment, and complete abolition of gonadal sources of testosterone often occurs. This study describes the biosterilant effects of administering three doses of Bacillus thuringiensis kurstaki HD-73 (Bt 5, 50, and 250 mg/kg; 20 rats/dose) extract in adult male Wistar albino rats on testicular parameters, function, histology, and a number of biochemical markers of overall health, free radical production, and cell proliferation. Intratesticular administration of Bt extract to rats induces testicular oxidative stress and damages and consequently, perturb spermatogenesis, degeneration of testis, reduction in testes size, and depletion of testosterone and antioxidant enzyme concentrations in a dose-dependent manner because of free radical-mediated lipid peroxidation. No morbidity or mortality adverse effects were observed in both the saline control and Bt extract-treated rats. Significant variation was noted in clinical manifestations, weight and volume of testes, and hormonal and biochemical profiles between Bt doses in comparison with the saline control. Aspermia/azoospermia (100%) resulted in Bt-treated rats without any adverse effects. Histopathological analysis showed degeneration, necrosis, vacuolation, fewer germ cells, formation of multinucleated giant cells, and a lack of elongated spermatids in atrophic seminiferous tubules in Bt extract-treated groups in the presence of low concentrations of testosterone, antioxidant enzymes, and suppression of germ cell proliferation. Dose-dependent effects were evident in most parameters that were measured. The vast array of tests that were undertaken also provides some important indicators of the physiological effects associated with the treatments that were applied. Intratesticular injection of Bt extract impairs spermatogenesis and induces permanent sterility in rats.

DNA methylation analysis in rat kidney epithelial cells exposed to 3-MCPD and glycidol.

3-Monochloropropane-1,2-diol (3-MCPD) is a well-known food processing contaminant that has been regarded as a rat carcinogen, which is known to induce Leydig-cell and mammary gland tumors in males, as well as kidney tumors in both genders. 3-MCPD is highly suspected to be a non-genotoxic carcinogen. 2,3-Epoxy-1-propanol (glycidol) can be formed via dehalogenation from 3-MCPD. We aimed to investigate the cytotoxic effects of 3-MCPD and glycidol, then to demonstrate the possible epigenetic mechanisms with global and gene-specific DNA methylation in rat kidney epithelial cells (NRK-52E). IC50 value of 3-MCPD was determined as 48 mM and 41.39 mM, whereas IC50 value of glycidol was 1.67 mM and 1.13 mM by MTT and NRU test, respectively. Decreased global DNA methylation at the concentrations of 100 µM and 1000 µM for 3-MCPD and 100 µM and 500 µM for glycidol were observed after 48 h exposure by using 5-methylcytosine (5-mC) ELISA kit. Methylation changes were detected in promoter regions of c-myc and Rassf1a in 3-MCPD and glycidol treated NRK-52E cells by using methylation-specific PCR (MSP), whereas changes on gene expression of c-myc and Rassf1a were observed by using real-time PCR. However, e-cadherin, p16, VHL and p15 genes were unmethylated in their CpG promoter regions in response to treatment with 3-MCPD and glycidol. Alterations in DNA methylation might be key events in the toxicity of 3-MCPD and glycidol.

Effect of piglet castration with nonsurgical sterilant on the zootechnical performance and pork carcass quality / Efeito da castração de leitões com esterilizante não cirúrgico no desempenho zootécnico e na qualidade da carcaça suína

A non-surgical sterilant (NSS) was used with the objective of assessing the zootechnical performance, carcass and meat quality, and hormone levels. 90 male piglets were selected with birthweights varying between 1.5kg to 2.0kg. The control group was constituted of 45 males castrated by the conventional surgical method, at the seventh day of age, and the treated group was constituted of 45 males castrated with NSS (active principle of zinc gluconate in the concentration of 26.2mg/mL associated to the dimethyl sulfoxide at 0.5%), with the application of the first dose on the seventh day of age and the second dose on the fourteenth day of age. The zootechnical assessments were carried out on the farm and consisted: weight gain in the periods per animal and feed conversion. The slaughter of the animals and the assessment of the carcass and meat quality and hormone levels were carried out in a slaughterhouse and the municipality of Campinas (SP). The study demonstrated that the use of NSS was a viable alternative in relation to the zootechnical performance and the carcass quality. In relation to the meat quality there was no significant difference in the majority of the assessed parameters.(AU)

Foi utilizado esterilizante não cirúrgico (ENC) com o objetivo de se avaliar o desempenho zootécnico e a qualidade de carcaça, de carne e de níveis hormonais. Foram selecionados 90 leitões machos de peso entre 1,5kg e 2,0kg ao nascimento. O grupo controle foi constituído por 45 machos castrados pelo método cirúrgico convencional, ao sétimo dia de idade, e o grupo tratado foi constituído por 45 machos castrados com ENC (princípio ativo de gluconato de zinco na concentração de 26,2mg/mL associado ao dimetil sulfóxido a 0,5%), com primeira dose de aplicação ao sétimo dia de idade e a segunda dose ao 14° dia de idade. As avaliações consistiram de: ganho de peso nos períodos por animal e conversão alimentar. O abate dos animais e a avaliação da carne e de níveis hormonais foram realizados em um frigorífico, na cidade de Campinas (SP). O uso de ENC foi uma alternativa viável em relação ao desempenho zootécnico e à qualidade da carcaça. Em relação à qualidade da carne, não houve diferença significativa na maioria dos parâmetros avaliados.(AU)

3-Monochloro-1,2-propanediol (3-MCPD) induces apoptosis via mitochondrial oxidative phosphorylation system impairment and the caspase cascade pathway.

3-Monochloro-1,2-propanediol (3-MCPD) is the most toxic chloropropanols compounds in foodstuff which mainly generated during thermal processing. Kidney is one of the primary target organs for 3-MCPD. Using human embryonic kidney cell (HEK293FT) as an in vitro model, we found that 3-MCPD caused concentration-dependent increase in cytoxicity as assessed by dye uptake, lactatedehydrogenase (LDH) leakage and MTT assays. HEK293FT cell treated with 3-MCPD suffered the decrease of mitochondrial membrane potential and the impairment of mitochondrial oxidative phosphorylation system, especially the reduced amount of mRNA expression and protein synthesis of electron transport chain complex II, complex IV, and complex III. More importantly, energy release (ATP synthesis) was significantly inhibited by 3-MCPD resulting from the down regulation expressions of ATP synthase (ATP6 and ATP8), as well as the loss of transmembrane potential required for synthesis of ATP. The decreased ratio of mitochondrial apoptogenic factors Bax/Bcl-2 and the cytochrome-c release from mitochondria to cytosol followed by the activation of apoptotic initiators caspase 9 and apoptotic executioners (caspase 3, caspase 6 and caspase 7) leading to apoptosis. The activation of caspase 8 and caspase 2 implied that there were probably other factors to induce the caspase-dependent apoptosis.

Chemosterilants for Control of Insects and Insect Vectors of Disease.

Both historically and at present, vector control is the most generally effective means of controlling malaria transmission. Insecticides are the predominant method of vector control, but the sterile insect technique (SIT) is a complementary strategy with a successful track record in both agricultural and public health sectors. Strategies of genetic and radiation-induced sterilization of Anopheles have to date been limited by logistical and/or regulatory hurdles. A safe and effective mosquito chemosterilant would therefore be of major utility to future deployment of SIT for malaria control. Here we review the prior and current use of chemosterilants in SIT, and assess the potential for future research. Recent genomic and proteomic studies reveal opportunities for specific targeting of seminal fluid proteins, and the capacity to interfere with sperm motility and storage in the female.

Effects of surgical and chemical sterilization on the behavior of free-roaming male dogs in Puerto Natales, Chile.

Population management of free-roaming domestic dogs (Canis lupus familiaris) is of interest due to the threat these animals pose to people, other animals and the environment. Current sterilization procedures for male dogs include surgical and chemical methods. However, little is known about how these procedures affect their behavior. The primary objective of this study was to investigate changes in selected behaviors following chemical and surgical sterilization in a male free-roaming dog (FRD) population in southern Chile. We also examined the association between serum testosterone levels and behaviors thought to be influenced by circulating androgens. A total of 174 dogs were randomly assigned to either a surgical or chemical sterilization group, or a control group. At the onset of the intervention period, 119 dogs remained and 102 dogs successfully completed the study. Each dog was monitored pre- and post-intervention using video recordings, GPS collars, and blood samples for the measurement of testosterone. Analysis of behavior revealed that surgically castrated dogs showed no reduction of sexual activity or aggression when compared to their pre-intervention behavior. Chemically sterilized dogs showed a statistically significant increase in dog-directed aggression, but no change in sexual activity. There was no change in home range size in any groups between the pre- and post-intervention measurement. We found no consistent association between levels of serum testosterone concentration and behavioral changes in any of the groups. This study presents the first detailed behavioral observations following surgical and chemical sterilization in male FRDs. The information generated is highly relevant to communities struggling with the control of FRDs. Complementary studies to further our understanding of the effects of male sterilization on the behavioral and reproductive dynamics of FRD populations are needed.

Guía de procedimientos de esterilización a baja temperatura / No disponible

No disponible

Transitory loss of glia and the subsequent modulation in inflammatory cytokines/chemokines regulate paracellular claudin-5 expression in endothelial cells.

Signaling mechanisms involved in regulating blood-brain barrier (BBB) integrity during central nervous system (CNS) inflammation remain unclear. We show that an imbalance between pro-/anti-inflammatory cytokines/chemokines alters claudin-5 expression. In vivo, gliotoxin-induced changes in glial populations and an imbalance between pro-/anti-inflammatory cytokine/chemokine expression occurred as BBB integrity was compromised. The balance was restored as BBB integrity was re-established. In vitro, TNF-α, IL-6, and MCP-1 induced paracellular claudin-5 expression loss. TNF-α- and IL-6- effects were mediated through the PI3K pathway and IL-10 attenuated TNF-α's effect. This study shows that pro-/anti-inflammatory modulators play a critical role in BBB integrity during CNS inflammation.

Changes in blood testosterone concentrations after surgical and chemical sterilization of male free-roaming dogs in southern Chile.

There is a growing interest in chemical sterilization as an alternative to surgical castration in large-scale sterilization campaigns to control canine populations. An important step toward understanding the short-term and long-term effects of chemical sterilants is to determine their impact on blood testosterone concentrations, particularly as these could influence dog behavior after treatment. A field trial was conducted with 118 free-roaming male dogs in the Chilean Patagonia, where 36 dogs were chemically sterilized using EsterilSol, 39 dogs were surgically castrated, and 43 dogs remained intact as controls. Blood testosterone levels were determined at four time periods: on enrollment 6 months before treatment (t-6m), at the time of treatment (t0, within one hour after surgical castration or chemical sterilization and during a concurrent 2-week period for the control group), four (t+4m), and six (t+6m) months after treatment. Intrinsic and temporal factors were evaluated; age was significantly associated with testosterone, where dogs 2- to 4-year-old had the highest testosterone concentrations (P = 0.036), whereas body weight and body condition scores were not associated with testosterone; testosterone concentration was not influenced by time of day, month, or season. After treatment (t+4m and t+6m), all of the surgically castrated dogs had testosterone concentrations below 1.0 ng/mL. On the basis of this cut point (<1 ng/mL), testosterone remained unchanged in 66% of the chemically sterilized dogs at both t+4m and t+6m; it remained low for 22% of dogs at both t+4m and t+6m; it was unchanged at t+4m but low at t+6m in 9% of dogs; and, it was low at t+4m but reverted back to unchanged at t+6m in one dog (3%). Incidentally, testosterone in chemically sterilized dogs increased dramatically within 1 hour of treatment (t0), more than doubling (131%) the concentration of control dogs at the time of treatment (t0), likely because of severe necrosis of interstitial cells. The use of EsterilSol as a method of sterilizing dogs had a variable effect on blood testosterone concentrations. Approximately, 30% of chemically sterilized dogs had a reduced testosterone concentration (actual maximum, 1 ng/mL) after 6 months, similar to that of surgically castrated dogs. Most chemically sterilized dogs, however, showed no long-term changes in blood testosterone concentrations.

Dihydroisoxazole inhibitors of Anopheles gambiae seminal transglutaminase AgTG3.

BACKGROUND: Current vector-based malaria control strategies are threatened by the rise of biochemical and behavioural resistance in mosquitoes. Researching mosquito traits of immunity and fertility is required to find potential targets for new vector control strategies. The seminal transglutaminase AgTG3 coagulates male Anopheles gambiae seminal fluids, forming a 'mating plug' that is required for male reproductive success. Inhibitors of AgTG3 can be useful both as chemical probes of A. gambiae reproductive biology and may further the development of new chemosterilants for mosquito population control. METHODS: A targeted library of 3-bromo-4,5-dihydroxoisoxazole inhibitors were synthesized and screened for inhibition of AgTG3 in a fluorescent, plate-based assay. Positive hits were tested for in vitro activity using cross-linking and mass spectrometry, and in vivo efficacy in laboratory mating assays. RESULTS: A targeted chemical library was screened for inhibition of AgTG3 in a fluorescent plate-based assay using its native substrate, plugin. Several inhibitors were identified with IC50 < 10 µM. Preliminary structure-activity relationships within the library support the stereo-specificity and preference for aromatic substituents in the chemical scaffold. Both inhibition of plugin cross-linking and covalent modification of the active site cysteine of AgTG3 were verified. Administration of an AgTG3 inhibitor to A. gambiae males by intrathoracic injection led to a 15% reduction in mating plug transfer in laboratory mating assays. CONCLUSIONS: A targeted screen has identified chemical inhibitors of A. gambiae transglutaminase 3 (AgTG3). The most potent inhibitors are known inhibitors of human transglutaminase 2, suggesting a common binding pose may exist within the active site of both enzymes. Future efforts to develop additional inhibitors will provide chemical tools to address important biological questions regarding the role of the A. gambiae mating plug. A second use for transglutaminase inhibitors exists for the study of haemolymph coagulation and immune responses to wound healing in insects.