Síntese quimioenzimática do levetiracetam e análogos

Pós-graduação em Química - IQ

Síntese de aminochalconas e análogos arílicos como agentes antivirais, antifúngicos e inibidores de mieloperoxidase

Pós-graduação em Química - IBILCE

Induction of multiple ovulations in mares using low doses of GnRH agonist Deslorelin Acetate at 48 hours after luteolysis

This study was aimed to test low doses of a GnRH agonist, deslorelin acetate (DA), for induction of multiple ovulations in mares and to determine its impact upon their reproductive efficiency. Seven mares aging from 8-20 years were used in three consecutive reproductive cycles. Mares were initially monitored by ultrasound irrespectively of cycle stage, inseminated and submitted to embryo collection (EC) (T1). Immediately after, mares received 7.5 mg dinoprost tromothamine (DT) and were monitored by ultrasound twice a day until larger follicle reached 23-25mm and the second >18mm (T2). At this time point, mares received 100 mu g DA and ovulation was induced with 1000 mu g DA and 1000IU hCG when largest follicle reached 33-35mm in diameter, followed by EC. Mares were further allocated to T3 when received 7.5 mg DT after EC on 12 and 100 mu g DA 48 h later. DA treatment was performed until dominant follicle reached 34 +/- 1 mm or 6 days of application. All EC were performed 8 days after ovulation. Mares with multiple ovulations in T1, T2 and T3 were 14.28% (1/7), 100.00% (7/7) and 0.00% (0/7), respectively, and averaged 0.43 +/- 0.53 in T1, 0.86 +/- 0.38 in T2 and 0.00 in T3 embryos per donor, respectively. Embryo recovery rate was 43.00% in T1, 85.71% in T2 and 0.00% T3. In conclusion, use of DA in mares with follicles larger than 25mm enhanced dominant and co-dominant follicle growth, that ultimately increased the incidence of multiple ovulations and embryo recovery rate.

GnRH/GnIH e seus receptores no sistema olfato-retinal de zebrafish

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeito citotóxico e antimicrobiano de análogos de peptídeos catiônicos e sua influencia na expressão de marcadores fenotípicos e genotípicos de mineralização dentinária

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Novas alternativas terapêuticas para o tratamento da Criptococose: análogos de Resveratrol e microRNAs

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Diâmetro folicular e taxa de prenhez em protocolo de sincronização com GnRH ou Benzoato de Estradiol no dia 0 em vacas de corte

This work aimed to evaluate the pregnancy rate and follicular diameter using EB or GnRH on the insertion of progesterone implant (D0) in lactating beef cows. Two groups were tested in two experiments. In Exp. 1 were used 61 Nelore cows divided into two groups: G-BE (n = 32) and G-GnRH (n = 29), on D0 was inserted P4 implant (CIDR ) and applied 2 mL of BE (G-BE) or 2.5 mL GnRH (G-GnRH). In D9 was performed ultrasonography (U.S.) to measure the diameter of the dominant follicle (DF) present in the ovary and the implant was removed, with concomitant administration of 2.5 mL of PGF2a and estradiol cypionate (ECP ) followed by calves removal. After 48 hours all the cows were inseminated and the calves returned. In Exp. 2 50 cows were used following the same protocol described above, but the pregnancy was assessed without performing ovarian US. There was no difference (p>0.05) in pregnancy rate between treatments, BE (55%) or GnRH (41%), but the follicular diameter was significantly higher (p<0.05) in pregnant cows treated with EB (10.7 mm vs. 8.5 mm) and in cows treated with GnRH there was no difference (p>0.05) between pregnant and no pregnant cows (11.6 mm vs. 10.2 mm). We concluded the use of GnRH on D0 did not improve the pregnancy rate in lactating beef cows and follicular diameter was greater (p <0.05) in pregnant cows compared to non-pregnant only in G-BE.

Pensamento, linguagem e língua escrita segundo a epistemologia genética: processos e construções análogos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

AÇÃO REGULATÓRIA DO GnRH NO DESENVOLVIMENTO EMBRIONÁRIO PRECOCE E VITRIFICAÇÃO DE EMBRIÕES SUÍNOS PELO MÉTODO DE MICROGOTA (ROLE OF GnRH DURING EARLY EMBRYONIC DEVELOPMENT AND DEVELOPMENT OF SWINE EMBRYOS FOLLOWING VITRIFICATION BY MICRODROPLET METHOD)

The objective of this study was to investigate the role of GnRH on the preimplantation development of mouse embryos in vitro. GnRH-I, GnRH-II, and GnRH agonists: Des-Gly, Des-Trp and histrelin did not improve embryo development. However, treatment with the specific GnRH antagonist SB-75 blocked embryo development at morula stage. The inhibition of embryo development by SB-75 could be rescued by the addition of histrelin. To determine which intracellular signaling cascade is involved following binding of GnRH to the GnRHR, embryos were cultured in the presence of specific PKC (GFX) or PKA (SQ22536) inhibitors. The PKC inhibitor blocked embryo development at a similar stage as SB-75, whereas SQ22536 had an inhibitory effect, diminishing blastocyst formation and hatched rates. There are evidences that GnRH has an essential autocrine effect on mouse embryonic development via GnRHR, probably by activating PKC signaling cascade while the inhibition of the GnRH signaling does not activate apoptotic mechanisms involving caspase-3. In another experiment, development in vitro of embryos from Chinese Meishan (M) and occidental white crossbred (WC) females were investigated after improving the vitrification protocol for pig embryos. Efficient cryopreservation of zona pellucida-intact porcine embryos and studies of the difference among breeds could greatly impact the swine industry. The percentage of embryos surviving 24 h after cryopreservation without lysis or degeneration was higher for M (72%) than WC (44%). However, in vitro development of embryos that survived cryopreservation was not different between M and WC at the expanded (64%) or hatched (22%) blastocyst stages. Developmental rates were significantly higher for control embryos than frozen embryos from both breeds at expanded blastocyst stage, but not at hatched blastocyst stage. Rates of expanded blastocyst formation did not differ between M and WC control embryos (98 and 95%, respectively). With a new procedure to warm vitrified pig embryos, the survival rates may be improved. The optimal stages to vitrify pig embryos using the microdroplet method ranges from late compact morula to early expanded blastocyst. The results suggest that M embryos have a higher capacity to survive the vitrification process than WC embryos. O objetivo do presente estudo foi investigar a importância do GnRH no desenvolvimento embrionário precoce em camundongos. GnRH-I, GnRH-II e os GnRH agonistas: Des-Gly, Des-Trp e histrelina não incrementaram o desenvolvimento embrionário. Entretanto, o tratamento com SB-75, um antagonista específico do GnRH, bloqueou o desenvolvimento embrionário no estádio de mórula. A inibição do desenvolvimento embrionário pelo SB-75 pôde ser revertida com a adição de histrelina. Para determinar a cascata do sinal intracelular desencadeada pela ligação do GnRH com o seu receptor, embriões foram cultivados na presença de inibidores específicos da PKC (GFX) e da PKA (SQ22536). O inibidor da PKC bloqueou o desenvolvimento embrionário em estádio similar ao bloqueio mediado pelo SB- 75, enquanto o SQ22536 teve efeito inibitório diminuindo a formação de blastocisto e taxas de eclosão. Os resultados sugerem que o GnRH tem um efeito autócrino essencial no desenvolvimento embrionário através do GnRHR, provavelmente, ativando a cascata da PKC. Por outro lado, a inibição do sinal do GnRH não ativa mecanismos apoptóticos que involvam caspase-3. Em outro experimento, foi investigado o desenvolvimento in vitro de embriões da raça Meishan (M) e branco cruzado (WC) após vitrificação pelo método microgota. O desenvolvimento de protocolos eficientes para criopreservação de embriões suínos com a zona pelúcida intacta e a avaliação das diferenças entre raças pode ter um significativo impacto na suinocultura. A percentagem de embriões que sobreviveram à criopreservação depois de 24 h foi maior na M (72%) do que na WC (44%). No entanto, o desenvolvimento in vitro dos embriões que sobreviveram à criopreservação não foi diferente entre M e WC nos estádios de blastocisto expandido (64%) ou eclodido (22%). Os índices de desenvolvimento foram significativamente mais altos para os embriões controle do que para os embriões vitrificados nas duas raças no estádio de blastocisto expandido, porém não foram diferentes para o estádio de blastocisto eclodido. A formação de blastocisto expandido não diferiu entre os embriões controle M e WC (98 e 95%, respectivamente). Com o novo procedimento (“hot warm”) para descongelar embriões vitrificados pelo método de microgota, pode-se aumentar dos índices de sobrevivência. Os melhores estádios embrionários para a vitrificação de embriões suínos variam de mórula compacta tardia até blastocisto expandido inicial. Os resultados sugerem que embriões M têm mais capacidade de sobreviver ao processo de vitrificação do que embriões WC.

LH surge in response to the treatment with GnRH analog or estradiol in ovariectomized buffaloes with or without progesterone pre-exposition

The aim of the present study was to evaluate the LH surge after EB (estradiol benzoate) or GnRH administration with or without P4 (progesterone) pre-exposure in ovariectomized (OVX) buffalo cows. Females were randomly assigned to receive an intravaginal P4 device (D0–D9). They were then given EB 24 h or GnRH 36 h post-P4 device removal (factorial 2×2, n=6 per group). Blood collection for LH measurement began 36 h after the P4 device removal and continued at 3 h intervals. The area under the LH curve (AUC; 30.2 ng2 and 13.41 ng2; P=0.007) and the area of the LH peak (AP; 19.0 ng2 and 8.9 ng2; P=0.009) were greater for EB than GnRH. We did not observe an effect of P4 pre-exposure on the AUC and AP. Furthermore, there was no interaction between P4 pre-exposure and EB or GnRH treatment on the AUC and AP. However, there was an interaction (P<0.01) between P4 pre-exposure and the type of inducer (EB or GnRH) to release a preovulatory-like LH surge at the beginning (BP), final (FP) and time (TP) of the LH peak. The P4 pre-exposure anticipated the BP (2.5 and 7.4 h), TP (6.0 and 12.0 h) and FP (11.5 and 17.1 h) when EB was used to induce a preovulatory-like LH surge (P<0.01). However, there was no effect of P4 pre-exposure on BP (0.4 and 0.4 h), TP (3.0 and 3.0 h) and FP (5.9 and 6.1 h) with GnRH treatment. There was also no effect of the pre-exposure to P4, type of inducer or interaction on the amplitude of the LH peak. We concluded that EB therefore led to greater LH release than GnRH, and pre-exposure to P4 before EB administration anticipated the preovulatory-like LH surge in buffalo cows.

GnRH analogs do not protect ovaries from chemotherapy-induced ultrastructural injury in Hodgkin's lymphoma patients

To determine the protective effect of gonadotropin-releasing hormone analogs (GnRHa) using several ultrasound and endocrine markers to detect ultrastructural ovarian damage in Hodgkin's lymphoma patients.

Combination of gonadotropin-releasing hormone (GnRH) agonists with GnRH antagonists before chemotherapy reduce but does not completely prevent a follicle-stimulating hormone flare-up

Increasing evidence supports GnRH agonists to be an effective treatment to preserve ovarian function during chemotherapy, but the initial flare-up of FSH during the first week after GnRH agonist application still limits its use. The combination of GnRH agonists with GnRH antagonists might solve this problem to some extent as the addition of GnRH antagonists at least significantly reduces the FSH flare-up.