Nonextensive realizations in interacting ion channels: Implications for mechano-electrical transducer mechanisms.

We propose a theoretical model to investigate the thermodynamics of single and coupled two-state ion channels, associated with mechanoelectrical transduction (MET) and hair cell biophysics. The modeling was based on the Tsallis nonextensive statistical mechanics. The choice for a nonextensive framework in modeling ion channels is encouraged on the fact that we take into account the presence of interactions or long-range correlations in the dynamics of single and coupled ion channels. However, the basic assumptions that support Boltzmann-Gibbs statistics, traditionally used to model ion channel dynamics, state that the system is formed by independent or weakly interacting elements. Despite being well studied in many biological systems, the literature has not yet addressed the study of both entropy and mutual information related to isolated or physically interacting pairs of MET channels. Inspired by hair cell biophysics, we show how the presence of nonextensivity, or subadditivity and superadditivity modulates the nonextensive entropy and mutual information as functions of stereocilia displacements. We also observe that the magnitude of the interaction between the two channels, given by a nonextensive parameter, influences the amplitude of the nonextensive joint entropy and mutual information as functions of the hair cell displacements. Finally, we show how nonextensivity regulates the current versus displacement curve for a single and a pair of interacting two-state channels. The present findings shed light on the thermodynamic process involved in the molecular mechanisms of the auditory system.

Pulmonary adenocarcinoma in a captive ocelot (Leopardus pardalis): morphologic and immunophenotypic characterization - case report / Adenocarcinoma pulmonar em uma jaguatirica (Leopardus pardalis) de cativeiro: caracterização morfológica e imunofenotípica - relato de caso

Pulmonary adenocarcinoma is a malignant epithelial neoplasia that usually arises from conducting airways or alveolar parenchyma. It has rarely been described in wild felids, with no previous reports in ocelots. In domestic cats it is a very aggressive neoplasm with a high metastatic rate that usually evolves to death. This report aimed to describe a pulmonary adenocarcinoma in a captive and senile ocelot (Leopardus pardalis), with a thorough morphologic and immunophenotypically characterization, evidencing the epithelial-mesenchymal transition (EMT) phenomenon in a high metastatic carcinoma, an important feature rarely described in veterinary medicine, even in domestic cats.(AU)

O adenocarcinoma pulmonar é uma neoplasia epitelial maligna originada do epitélio respiratório das vias aéreas inferiores e do parênquima alveolar. É uma neoplasia raramente descrita em felinos selvagens, sem nenhum relato em jaguatiricas. Em gatos domésticos, é uma neoplasia muito agressiva, com alta taxa de metástase, e geralmente evolui para o óbito do paciente. O presente relato objetiva descrever um adenocarcinoma pulmonar em uma jaguatirica (Leopardus pardalis) senil de cativeiro, com detalhada caracterização morfológica e imunofenotípica, evidenciando o fenômeno de transição epitelial-mesenquial (TEM) em um carcinoma altamente metastático, uma característica importante, com escassos relatos na medicina veterinária, mesmo em gatos domésticos.(AU)

Cutaneous mast cell tumor in a captive Bush dog (Speothos venaticus): pathological and immunophenotypical aspects - case report / Mastocitoma cutâneo em um cachorro-do-mato vinagre (Speothos venaticus) de cativeiro: aspectos patológicos e imunofenotípicos - relato de caso

A senile male captive bush dog (Speothos venaticus) presented a small perianal cutaneous nodule. Histologically, there was an ulcerated round cell tumor composed of well differentiated mast cells with abundant intracytoplasmic purple Giemsa-positive granules, with a diffuse eosinophilic infiltrate. Immunohistochemistry revealed that 30% of the neoplastic cells were positive for Kit in the cytoplasm and cell membrane, and all neoplastic cells were negative for MAC and CD3. Less than 10% of the neoplastic cells were positive for Ki67. At necropsy other primary tumors were identified in this animal, including an intestinal adenoma, an adrenal cortex adenoma and a testicular interstitial cell tumor.(AU)

Um cachorro-vinagre (Speothos venaticus) apresentou um nódulo cutâneo pequeno na região perianal. Histologicamente havia neoplasia cutânea de células redondas e ulcerada, constituída por mastócitos bem diferenciados, com abundantes grânulos citoplasmáticos metacromáticos na coloração de Giemsa e infiltrado eosinofílico difuso. A imuno-histoquímica demonstrou que 30% das células neoplásicas eram positivas para a proteína Kit no citoplasma e na membrana celular. As células foram negativas para MAC e CD3. Menos de 10% das células neoplásicas foram positivas para Ki67. Durante a necropsia, foram identificados outros tumores primários, como adenoma intestinal, adenoma cortical da adrenal e tumor de células intersticiais do testículo.(AU)

Morphological and molecular diagnosis of diseases of free-ranging crab-eating foxes (Cerdocyon thous) / [Diagnóstico morfológico e molecular de doenças de cachorro-do-mato (Cerdocyon thous) de vida livre]

The aim of this study was to investigate the occurrence of diseases in free-ranging wild canids that were roadkill on highways in the State of Espírito Santo, Brazil. PCR tests were performed for the detection of Brucella sp., Babesia sp., Rangelia sp., and Hepatozoon sp. in the spleen. Morphological evaluation and identification of parasites was performed in the liver and lung. Twenty specimens of C. thous were necropsied at the Animal Pathology Sector of the Veterinary Hospital of the Universidade Federal do Espírito Santo. Tissue samples were processed for histopathological examination and polymerase chain reaction (PCR) analysis. There was no PCR amplification of genomic DNA sequences of Brucella sp., Babesia sp., Rangelia sp., and Hepatozoon sp. using DNA extracted from the spleen as template. Histologically, lesions associated with parasitism by Platynosomum sp. and Angiostrongylus sp. were observed in the liver and lung, respectively. This is the first report of Platynosomum sp. and Angiostrongylus sp. parasitism in C. thous in the state of Espírito Santo, Brazil. Therefore, this study demonstrated parasitism of crab-eating foxes by Platynosomum sp. and Angiostrongylus sp. Importantly, no evidence of infection with Brucella sp., Babesia sp., Rangelia sp., and Hepatozoon sp. was obtained by PCR analysis.(AU)

O objetivo deste estudo foi investigar a ocorrência de doenças em canídeos silvestres de vida livre que foram atropelados em rodovias no estado do Espírito Santo, Brasil. Testes de PCR foram realizados para a detecção de Brucella sp., Babesia sp., Rangelia sp. e Hepatozoon sp. no baço. A avaliação morfológica e a identificação de parasitas foram realizadaa no fígado e no pulmão. Vinte espécimes de C. thous foram necropsiados no Setor de Patologia Animal do Hospital Veterinário da Universidade Federal do Espírito Santo. Amostras de tecido foram processadas para exame histopatológico e análise de reação em cadeia da polimerase (PCR). Não houve amplificação por PCR das sequências de DNA genômico de Brucella sp., Babesia sp., Rangelia sp. e Hepatozoon sp. usando-se DNA extraído do baço como modelo. Histologicamente, lesões associadas ao parasitismo por Platynosomum sp. e Angiostrongylus sp. foram observadas no fígado e no pulmão, respectivamente. Este é o primeiro relato de Platynosomum sp. e Angiostrongylus sp. parasitismo em C. thous no estado do Espírito Santo, Brasil. Portanto, este estudo demonstrou parasitismo de cachorro-do-mato por Platynosomum sp. e Angiostrongylus sp. É importante detacar que não há evidências de infecção por Brucella sp., Babesia sp., Rangelia sp. e Hepatozoon sp. por análise de PCR.(AU)

Brain teratoma in a free-ranging mallard (Anas platyrhynchos) - case report / [Teratoma cerebral em um pato-real (Anas platyrhynchos) de vida livre - relato de caso]

Teratoma is a rare neoplasia with differentiation in two or three germ cell lines. Intracranial teratoma in birds has rarely been reported, especially affecting the brain. This is the first report of a brain teratoma in a mallard with neurological clinical signs. The neoplasm was characterized as a mature brain teratoma, extending from the cerebellum to the brainstem, and with one nodule in the cortex.(AU)

O teratoma é uma neoplasia rara, com diferenciação em duas ou três linhagens de células germinativas. Teratomas intracranianos, em aves, são raramente relatados, principalmente, com localização cerebral. Este é o primeiro relato de teratoma cerebral em um pato-real com sinais clínicos neurológicos. A neoplasia foi caracterizada como um teratoma cerebral maduro, estendendo do cerebelo ao tronco encefálico e com um nódulo no córtex.(AU)

Dioctophymosis in a free-ranging maned wolf (Chrysocyon brachyurus): clinical-therapeutic, ultrasonographic and pathological aspects - case report / [Dioctofimose em um lobo guará (Chrysocyon brachyurus) de vida livre: aspectos clínico-terapêuticos, ultrassonográficos e patológicos - relato de caso]

Dioctophymosis is the disease caused by Dioctophyma renale, a large nematode, popularly known as giant kidney worm, and whose definitive hosts are the domestic dog and many wild mammal species. There are some reports of maned wolf parasitism by D. renale, however, in most cases the reports are restricted to the finding of the parasite during necropsy, without clinical assessment. The present report aimed to describe the clinical-therapeutic, ultrasonographic and pathological aspects of D. renale parasitism in a free-ranging maned wolf, emphasizing the treatment with an association of doramectin, praziquantel, pyrantel pamoate, and febantel that resulted in complete elimination of the parasite.(AU)

A dioctofimose é a doença causada pelo Dioctophyma renale, um nemátodo grande, popularmente chamado de verme gigante do rim e que tem como hospedeiro definitivo o cão doméstico e inúmeras espécies de mamíferos silvestres. Existem alguns relatos do parasitismo do lobo-guará por D. renale, contudo, na maioria das vezes, os relatos se restringem apenas ao achado do parasita durante a necropsia, sem a correlação clínica. O presente relato objetiva descrever os aspectos clínico-terapêuticos, ultrassonográficos e patológicos do parasitismo por D. renale em um lobo-guará de vida livre, enfatizando o tratamento com uma associação de doramectina, praziquantel, pamoato de pirantel e febantel, o que resultou na eliminação completa do parasita.(AU)

Correction to: Statistical crossover and nonextensive behavior of neuronal short-term depression.

The authors apologize for the following errors published in the article. However, these errors do not modify the main assumptions in our work nor affects the discussion (interpretation) of the results.

Statistical crossover and nonextensive behavior of neuronal short-term depression.

The theoretical basis of neuronal coding, associated with short-term degradation in synaptic transmission, is a matter of debate in the literature. In fact, electrophysiological signals are commonly characterized as inversely proportional to stimulus intensity. Among theoretical descriptions of this phenomenon, models based on 1/f-dependency are employed to investigate the biophysical properties of short-term synaptic depression. In this work, we formulate a model based on a paradigmatic q-differential equation to obtain a generalized formalism useful for investigation of nonextensivity in this specific type of synaptic plasticity. Our analysis reveals nonextensivity in data from electrophysiological recordings and also a statistical crossover in neurotransmission. In particular, statistical transitions provide additional support to the hypothesis of heterogeneous release probability of neurotransmitters. On the other hand, the simple vesicle model agrees with data only at low-frequency stimulations. Thus, the present work presents a method to demonstrate that short-term depression is not only governed by random mechanisms but also by nonextensive behavior. Our findings also conciliate morphological and electrophysiological investigations into a coherent biophysical scenario.

Maximum-likelihood q-estimator uncovers the role of potassium at neuromuscular junctions.

Recently, we demonstrated the existence of nonextensive behavior in neuromuscular transmission (da Silva et al. in Phys Rev E 84:041925, 2011). In this letter, we first obtain a maximum-likelihood q-estimator to calculate the scale factor ([Formula: see text]) and the q-index of q-Gaussian distributions. Next, we use the indexes to analyze spontaneous miniature end plate potentials in electrophysiological recordings from neuromuscular junctions. These calculations were performed assuming both normal and high extracellular potassium concentrations [Formula: see text]. This protocol was used to test the validity of Tsallis statistics under electrophysiological conditions closely resembling physiological stimuli. The analysis shows that q-indexes are distinct depending on the extracellular potassium concentration. Our letter provides a general way to obtain the best estimate of parameters from a q-Gaussian distribution function. It also expands the validity of Tsallis statistics in realistic physiological stimulus conditions. In addition, we discuss the physical and physiological implications of these findings.

Proteomic analysis of seminal plasma and sperm cells and their associations with semen freezability in Guzerat bulls.

The objective of the present study was to describe the relationship of seminal plasma and total sperm cell proteins with the semen freezability parameters of Guzerat bulls. Thirteen bulls were subjected to breeding soundness evaluation. Semen samples were collected, cryopreserved, and then post-thawing sperm kinetics were assessed, where high ( = 7) and low ( = 6) freezability groups were defined. Seminal plasma and total sperm proteins from the 2 groups were separated by 2-dimensional SDS-PAGE, and spots were identified by mass spectrometry. Semen parameters post-cryopreservation were as follows in the high and low freezability groups, respectively: mean total motility, 52.4 ± 20.5 and 13.7 ± 3.9; percentage of normal sperm, 89.0 ± 2.6 and 64.7 ± 14.0; and reactivity of hypo-osmotic swelling test, 38.9 ± 4.7 and 13.6 ± 3.7. Three seminal plasma proteins (osteopontin-K, DNase γ precursor, and DNASE1L3) and 6 proteins from sperm cells (acrosome formation-associated factor isoform 2, annexin A1, disintegrin and metalloproteinase domain-containing protein 2, dihydrolipoyl dehydrogenase, and glyceraldehyde-3-phosphate dehydrogenase) were highly expressed ( < 0.05) in the high freezability group. Another 6 seminal plasma proteins (acrosin inhibitor 1, glutathione peroxidase 3, metalloproteinase inhibitor 2, ephrin-A1, annexin A1, and platelet-activating factor acetylhydrolase) were significantly higher ( < 0.05) in the low freezability group. We described the associations of seminal plasma and sperm cell proteins with post-thawing sperm viability of Guzerat bulls raised in a typical semiarid environment. Such associations indicate that specific seminal plasma proteins more abundant in bulls of low semen freezability may be a response to an early oxidative stress that is not detected by conventional prefreezing semen evaluation. Moreover, specific sperm proteins were more associated with good freezability. The results presented here can serve as guidelines for future research aiming to develop better extenders and/or to improve bull semen selection for cryopreservation.

Selection strategies for dairy buffaloes: economic and genetic consequences.

Buffaloes are generally raised in Brazil without milk-recording programs, and thus without genetic evaluations of any of their traits. This study evaluated the economic impacts of three different selection strategies on buffalo populations and the evolution of genetic trends, genetic variances and inbreeding coefficients resulting from each of them. The selection strategies used were as follows: (i) random selection; (ii) phenotypic selection; and (iii) progeny testing (PT). As the numbers of herds enrolled in milk-recording programs increased, phenotypic selection and PT strategies increased both monetary benefits and genetic trends. The extra costs of implementing milk recording (MR) and PT procedures were exceeded by the income resulting from better buffalo performance. Progeny testing is known to result in beneficial genetic trends and the use of artificial insemination promoted better distributions of genetic material into herds that were not enrolled in milk-recording programs. Phenotypic selection and PT increased mean milk production--a key factor in profitability. Inbreeding levels remained stable with phenotypic selection, even as the numbers of MR herds increased. Increases in the numbers of sires that were evaluated reduced the mean inbreeding coefficient in PT. Increasing the number of herds enrolled in milk-recording programs resulted in increased numbers of sires needed for PT, but this did not increase the inbreeding coefficient. In summary, phenotypic selection and PT strategies appear to be economically viable for buffalo husbandry in south-eastern Brazil under current (2007-2008) economic conditions and should be encouraged.

Firing patterns and synchronization in nonsynaptic epileptiform activity: the effect of gap junctions modulated by potassium accumulation.

Several lines of evidence point to the modification of firing patterns and of synchronization due to gap junctions (GJs) as having a role in the establishment of epileptiform activity (EA). However, previous studies consider GJs as ohmic resistors, ignoring the effects of intense variations in ionic concentration known to occur during seizures. In addition to GJs, extracellular potassium is regarded as a further important factor involved in seizure initiation and sustainment. To analyze how these two mechanisms act together to shape firing and synchronization, we use a detailed computational model for in vitro high-K(+) and low-Ca(2+) nonsynaptic EA. The model permits us to explore the modulation of electrotonic interactions under ionic concentration changes caused by electrodiffusion in the extracellular space, altered by tortuosity. In addition, we investigate the special case of null GJ current. Increased electrotonic interaction alters bursts and action potential frequencies, favoring synchronization. The particularities of pattern changes depend on the tortuosity and array size. Extracellular potassium accumulation alone modifies firing and synchronization when the GJ coupling is null.

Trypanosoma cruzi: in vitro activity of Epoxy-alpha-Lap, a derivative of alpha-lapachone, on trypomastigote and amastigote forms.

Chagas disease is an endemic parasitic infection caused by Trypanosomacruzi that affects 18-20 million people in Central and South America. Recently we described the Epoxy-alpha-Lap, an oxyran derivative of alpha-lapachone, which presents a low toxicity profile and a high inhibitory activity against T.cruzi epimastigotes forms, the non-infective form of this parasite. In this work we described the trypanocidal effects of Epoxy-alpha-Lap on extracellular (trypomastigote) and intracellular (amastigote) infective forms of two T. cruzi strains (Y and Colombian) known by their different infective profile. Our results showed that Epoxy-alpha-Lap is lethal to trypomastigote Y and Colombian strains (97% and 84%, respectively). Interestingly, Epoxy-alpha-Lap also showed a trypanocidal effect in human macrophage infected with T. cruzi Y (85.6%) and Colombian (71.9%) strains amastigote forms. Similar effects were observed on T. cruzi amastigote infected Vero cells (96.4% and 95.0%, respectively). Our results pointed Epoxy-alpha-Lap as a potential candidate for Chagas disease chemotherapy since it presents trypanocidal activity on all T. cruzi forms with low) toxicity profile.

Expression of B7-1 costimulatory molecules in patients with multibacillary leprosy and reactional states.

BACKGROUND: The expression of B7 as a costimulatory molecule on the surface of antigen-presenting cells such as macrophages and on dendritic cells characterizes the efficiency of the cell-mediated immune response. AIMS: Our purpose was to evaluate B7-1 expression in peripheral blood mononuclear cells (PBMCs) immediately after cell isolation ('spontaneous' B7 expression), and in inflammatory cells from cutaneous lesions of patients with multibacillary leprosy (MB-L) without and during the reactional states of erythema nodosum leprosum (ENL) or reversal reaction (RR). METHODS: Peripheral blood samples and skin biopsies of eight patients without (MB-L) and with reactional episodes (ENL and RR) were studied using antibodies against B7-1, CD1b, DR and CD14 in flow-cytometry and immunohistochemistry experiments. RESULTS: The flow-cytometry studies (mean +/- SD% of fluorescent cells) revealed significant B7-1 expression on PBMCs isolated from patients with ENL (8.0 +/- 0.6%) and RR (15.0 +/- 1.4%) compared with that observed for patients with MB-L (0.4 +/- 0.2%). Similar results were observed for cutaneous lesions of these patients by immunohistochemical assays. One patient studied before and during ENL revealed weak B7 expression before the reactional episode (0.3% of cells) compared with the marked level of B7-expressing cells detected during ENL (8.5% fluorescent cells). Interestingly, an even higher B7 expression (15% of cells) was observed in patients with RR. CONCLUSIONS: Our results strongly suggest that B7 expression precedes reactional episodes in MB-L, which could be related to the acquisition of effective immunity to Mycobacterium leprae during reactional episodes in leprosy. We propose B7 expression as a marker of CMI response in reactional episodes in leprosy.

HIV-1 reverse transcriptase: a therapeutical target in the spotlight.

Human Immunodeficiency Virus type 1 Reverse Transcriptase (HIV-1 RT) is one of the most important targets for treatment of Acquired Immune Deficiency Syndrome (AIDS). It catalyzes the reverse transcription of HIV-RNA into a double stranded DNA, and the knowledge of its substrate specificity and catalytic mechanism has guided the development of several inhibitors widely used on current HIV/AIDS therapy. However, mutations in HIV-1 RT structure can lead to the emergence of drug-resistant virus strains. The goal of this review is to summarize relevant structural features of HIV-1 RT and its inhibitors in such a way that this cost-effective target in the development of new antiretroviral drugs is particularly highlighted.

The effect of an oil drilling operation on the trace metal concentrations in offshore bottom sediments of the Campos Basin oil field, SE Brazil.

The concentrations of Al, Fe, Mn, Zn, Cu, Pb, Ni, Cr, Ba, V, Sn and As in offshore bottom sediments from the Bacia de Campos oil field, SE Brazil, were measured at the beginning and at 7 months after completion of the drilling operation. Concentrations of Al, Fe, Ba, Cr, Ni and Zn were significantly higher closer to the drilling site compared to stations far from the site. Average concentrations of Al, Cu, and in particular of Ni, were significantly higher at the end of the drilling operation than at the beginning. Comparison between drilling area sediments with control sediments of the continental platform, however, showed no significant difference in trace metal concentrations. Under the operation conditions of this drilling event, the results show that while changes in some trace metal concentrations do occur during drilling operations, they are not significantly large to be distinguished from natural variability of the local background concentrations.

Evaluation of B7-1 (CD80) and B7-2 (CD86) costimulatory molecules and dendritic cells on the immune response in leprosy.

The cell activation depends on T cell antigen receptor binding to antigen plus MHC and costimulation. The binding of CD28, expressed on the T cell surface to B7 (B7-1 or CD80/B7-2 or CD86) present on the antigen--presenting cells (APCs), determines, in several T cell function models, if activation or anergy follows antigenic stimulation. In leprosy, the role of CD80 and CD86 as costimulatory signal in M. leprae-specific cellular immunity has not yet been defined. We investigated the role of B7-CD28 pathway of T cell activation in the in vitro response to M. leprae, following stimulation in the presence of monocytes or dendritic cells (DCs) as APCs. Monocytes were purified, by cold aggregation, from peripheral blood mononuclear leukocytes (PBMC), isolated from leprosy patients. In order to obtain DCs, the monocytes were cultured in the presence of IL-4 and GM-CSF. T cells were purified from PBMC by negative selection with mABs and C'. The phenotype of the cell populations was monitored by FACS. Lymphoproliferative assays were performed with T cells, in the presence of monocytes or DCs. The cells were stimulated by M. leprae in the presence of anti-CD80 antibody (Ab) and/or anti-CD86 antibody (Ab) (Innogenetics). In some experiments Il-10, Il-12 and anti-Il-12 Ab were also added to the culture. We observed a significantly more efficient APC function for DCs when compared to monocytes in T cell in vitro responses to M. leprae. Regardless of the clinical form of Leprosy, the M. leprae-specific immune response was markedly reduced in the presence of anti-CD86 Ab. Il-12 increase the immune response to M. leprae while IL-10 or anti-IL-12 Ab reduce this response when monocytes or DCs were used as APCs.

Shedding of soluble receptor for tumor necrosis factor alpha induced by M. leprae or LPS from human mononuclear cells.

Cell surface expression and release of the tumor necrosis factor receptor (TNFR type I) was analyzed after stimulation of peripheral blood mononuclear cells (PBMC) with Mycobacterium leprae (M. leprae) or lipopolysaccharide (LPS). A transient spontaneous expression of TNFR type I on the surface of PBMC was observed. Two hr after activation with LPS, a significant reduction of TNFR type I expression was detected: Release of TNFR type I by M. leprae or LPS-stimulated PBMC was evaluated with an enzyme-linked immunoabsorbent assay. This release occurred relatively later (20 to 40 hr) than the secretion of TNF alpha which reached high levels between 8 to 20 hr after activation. Thalidomide, a potent drug for the treatment of erythema nodosum leprosum episodes by inhibiting TNF alpha production, had no influence on the TNFR type I expression. Similar results were obtained with pentoxifylline. It is concluded that the release of TNFR type I by M. leprae or LPS-stimulated PBMC may counteract the pro-inflammatory activities of TNF alpha, by reducing the systemic toxicity of this cytokine in leprosy.

Induçäo do parto em cabras de raças leiteiras mediante aplicaçäo de cloprostenol / Induction of parturition in dairy goat by administration of cloprostenol

Conduziram-se dois experimentos com o objetivo de avaliar a eficiência do cloprostenol em diferentes doses e vias de aplicaçäo na induçäo do parto em cabras. No primeiro, 14 cabras das raças leiteiras Anglo-Nubiana, Saanen e Pardo-Alpina foram submetidas, no 145º dia de prenhez, a três tratamentos: T1.1 = 25µg (n=04), T1.2 = 50µg (n=05) e T1.3 - 100µg (n=05) de cloprostenol, administrados por via intramuscular na vulva (IMV). Três cabras prenhes das mesmas raças foram utilizadas como controle. Os partos ocorreram com: T1.1 = 30,13ñ4,77h, T1.2 - 32,43ñ4,82h e T1.3 = 34,29ñ3,96h, e a amplitude do tempo de ocorrência dos partos foram de: 11,58h, 12,25h e 7,40h, respectivamente. Näo foram observadas diferenças estatísticas entre os tratamentos, embora T1.3 tenha apresentado uma resposta mais consistente (CV=11,55 por cento) que T1.1 (CV=15,83 por cento) e T1.2 (CV=14,86 por cento). No segundo experimento, 51 fêmeas das mesmas raças foram distribuídas, no 145º dia de prenhez, em quatro tratamentos: T2.1 = 25µg (n=14), T2.2= 50µg (n=12), T2.3 = 75µg (n=12) de cloprostenol administradas IMV e T2.4 - 75µg (n=13) de cloprostenol na musculatura da coxa (IM). Os intervalos entre a induçäo e o parto foram de: T2.1 = 34,89ñ13,57h, T2.2 = 30,06ñ3,82h, T2.3 = 29,99ñ1,81h e T2.4 = 37,44ñ22,15h. Näo houve diferença estatística significativa entre os tratamentos. Entretanto, T2.3 mostrou-se mais consistente ao apresentar coeficiente da variaçäo menor (CV=6,04 por cento) que T2.1 (CV=38,88 por cento), T2.2 (CV=12,70 por cento) e T2.4 (CV=59,17 por cento). Constatou-se, também, que os tratamentos permitiram a concentraçäo dos partos no 146º dia de prenhez, com amplitude de ocorrência de 0,62 dia e 3,07 dias no primeiro e segundo experimento, respectivamente, contra 11 dias para o grupo controle no primeiro experimento. Conclui-se que as doses de 25, 50 e 75µg de cloprostenol, aplicadas por via IMV, foram efetivas em induzir o parto em cabras, sendo a dose de 75µg aparentemente a mais eficaz