E.F. Nascimento

Venereal transmission of canine visceral leishmaniasis

Leishmania chagasi, the agent of visceral leishmaniasis in dogs in the Americas has a tropism to the male genital system, particularly the epididymis, prepuce, and glans penis, resulting in shedding of Leishmania in the semen. The goal of this study was to verify the possibility of venereal transmission of L. chagasi. Twelve Leishmania-free bitches, housed in the absence of the insect vector, copulated with multiple naturally infected dogs that were shedding Leishmania in the semen. PCR analysis of serially collected ejaculates indicated that shedding of Leishmania in the semen is intermittent. Three bitches seroconverted, and six were PCR positive by the end of the experimental period (165 days after the last copulation). These data support the notion that L. chagasi may be sexually transmitted from naturally infected dogs to susceptible bitches in the absence of the biological insect vector.

Genital Lesions Associated with Visceral Leishmaniasis and Shedding of Leishmania sp. in the Semen of Naturally Infected Dogs

Although visceral leishmaniasis is primarily transmitted by a biological invertebrate vector, transmission in the absence of the vector has been reported, including venereal transmission in humans. Considering the possibility of venereal transmission, we studied genital lesions in dogs naturally infected with visceral leishmaniasis and shedding of Leishmania sp. in the semen. Approximately 200 dogs were serologically tested for anti-Leishmania antibodies and divided into three groups: 1) serologically negative dogs (n = 20), 2) asymptomatic serologically positive dogs (n = 20), and 3) symptomatic serologically positive dogs (n = 20). Samples from both testes, all segments of both epididymes, prostate gland, glans penis, and prepuce were histologically evaluated and processed for immunodetection of Leishmania sp. Semen samples were obtained from 22 symptomatic serologically positive dogs and processed for detecting Leishmania DNA by polymerase chain reaction. A significantly higher frequency of inflammation was observed in the epididymes, glans penis, and prepuce of dogs with visceral leishmaniasis, which was associated with a high frequency of immunohistochemically positive tissues (up to 95% of tissues from symptomatic dogs were positive by immunohistochemistry). Leishmania DNA was detected in eight of 22 semen samples from symptomatic dogs. Together these findings indicate that genital lesions and shedding of Leishmania sp. (donovani complex) in the semen are associated with visceral leishmaniasis. Additional studies should address the possibility of venereal transmission of the disease in the dog.

Foliculogênese e esteroidogênese ovarianas em ratas adultas hipertireóideas

Ovarian folliculogenesis and steroidogenesis were studied in hyperthyroid adult rats. Hyperthyroidism was induced in 27 five month-old Wistar rats by daily administration of 50µg L-thyroxin. Other 27 rats were maintained in euthyroid state as controls. At 30, 60 and 90 days after the beginning of the treatment, nine rats from each group were sacrificed. The ovaries were weighed, inspected and processed for histomorphometric evaluation. Plasmatic levels of free T4, estradiol and progesterone were determined. The levels of T4 were significantly higher in the hyperthyroid rats at 30, 60 and 90 days, but significant differences on the ovarian weight were detected only at 90 days. The number of secondary and tertiary follicles and of corpus luteum was greater at 60 or 90 days, but the rate of follicular atresia was different only at 90 days. No significant differences were observed on the number of primary and pre-ovulatory follicles and on the concentrations of estradiol and progesterone. Our data suggest that hyperthyroidism stimulates ovarian folliculogenesis in sexually mature rats. Furthermore, there is a reduction on the rate of follicular atresia.

Relação tireóide-gônadas e níveis plasmáticos de fósforo, cálcio e fosfatase alcalina em ratas

The interrelation between thyroid, gonads and osseous metabolism was studied in either intact or castrated adult female rats kept under hyperthyroidism or euthyroidism for 30, 60, or 90 days. Plasmatic levels of phosphorus, calcium, and alkaline phosphatase were measured to assess the osseous metabolism. These characteristics were correlated to the levels of estrogen, progesterone, and free T4. Either hypogonadism or hyperthyroidism interfered with the plasmatic characteristics of osseous metabolism. Hyperphosphatemia and hypocalcemia were induced by hyperthyroidism, whereas the hypogonadism had little effect on the levels of phosphorus, but it had a potencialization effect on the hyperphosphatemia and hypocalcemia induced by hyperthyroidism. The effect of hypogonadism on the alkaline phosphatase activity was reduced by the hyperthyroidism.

Efeito da associação hipertireoidismo-castração no osso de ratas adultas

The relationship between thyroid, gonads and bone morphology was investigated in 5 month-old Wistar rats, castrated and kept in hyperthyroid or euthyroid state for periods of 30, 60 and 90 days. A non-castrated control group was maintained in the same condition. At the end of each period, plasma concentrations of free T4, progesterone and estradiol were measured. The bones from each group were submitted to radiological and histological analysis. Hyperthyroidism in intact rats caused variation in bone morphology throughout the experiment, leading to loss of trabecular bone tissue at day 60, due to increased bone resorption. At day 90 there was no bone loss, because the increase in bone resorption was accompanied by higher bone apposition. In castrated euthyroid rats reduction in progesterone levels inhibited the bone apposition, causing a slight loss of trabecular bone tissue in vertebrae and alveolar bone at day 30, which was intensified at days 60 and 90, affecting cortical bone tissue. The administration of thyroxine to castrated rats reversed osteopenia at days 30 and 60, which did not occur at day 90 when bone loss was more extensive. In conclusion, hypoprogesteronism and hypoestrogenism alter bone metabolism and the bone response to hyperthyroidism depends on the plasma profile of sex steroids, time of exposure and bone tissue configuration.

Fetal growth restriction in hypothyroidism is associated with changes in proliferative activity, apoptosis and vascularisation of the placenta

The objective of this study was to evaluate fetal weight, histomorphometric changes and proliferative activity, apoptosis and angiogenesis of the placenta in rats with hypothyroidism. Thirty-six adult female rats were divided into two groups with 18 animals each: control and hypothyroidism. Hypothyroidism was induced by daily administration of propylthiouracil (1 mg/animal). The administration began five days before becoming pregnant and the animals were sacrificed at 14 or 19 days of gestation. The control group received a placebo. The number and weight of fetuses and the rate of fetal death was determined, as well as the morphometric characteristics, the immunohistochemical expression of cell division control protein 47 (CDC)-47 and vascular endothelial growth factor (VEGF) and the number of apoptotic cells in the placental disk. The data were analysed by Mann-Whitney U test. Hypothyroidism reduced the weight of fetuses and of the uterus and placenta (P<0.05), altered the thickness of the placental labyrinth and spongiotrophoblast (P<0.05), increased the population of glycogen cells in the spongiotrophoblast (P<0.05), interfered with the vascular development of the placental labyrinth and decreased VEGF expression (P<0.05), reduced the expression of CDC-47 and cellularity and increased the apoptotic rate in the placental disk (P<0.05). We conclude that hypothyroidism affects fetal weight by altering the proliferative activity, apoptosis and vascularisation of the placenta.

Uterine leiomyoma in chimpanzee (Pan troglodytes)

Uma chimpanze de 22 anos de idade foi necropsiada com historico clinico de anorexia, vomitos frequentes e desidratacao consequentes a gastrite iatrogenica. Macroscopicamente, o utero apresentava-se aumentado de volume, com o lumen totalmente ocluido por nodulos firmes, esbranquicados e coalescentes que se estendiam para o miometrio. Histologicamente, os nodulos eram constituidos por leiomiocitos bem diferenciados dispostos em varias direcoes e com coloracao caracteristica pelo tricromio de Gomori e Masson. Pela imunoistoquimica, as celulas neoplasicas apresentavam marcacao forte e difusa de receptores para progesterona e estrogeno, assim como de actina alfa de musculo liso. Algumas celulas neoplasicas e o estroma apresentavam marcacao para vimentina e poucas celulas neoplasicas foram positivas para MIB-1. Com base nas caracteristicas mosrfologicas e imunoistoquimicas foi firmado o diagnostico de leiomioma uterino.

Histomorfometria e histoquímica dos ovários, tubas e útero de ratas hipotireóideas em metaestro-diestro

Ovarian folicullogenesis was studied in adult Wistar rats. The animals were hypothyroid in the metaestrus/diestrus phase of the estrous cycle. Hypothyroidism was induced by oral treatment with 1mg/animal of propylthiouracil. Euthyroid rats were kept under the same experimental conditions receiving placebo. After 120 days under treatment, all animals were killed and plasma was taken to assessing free thyroxine, progesterone, and estradiol. The ovaries, tubes and uterus were sampled for histomorphometric and histochemistry evaluation. Hypothyroidism significantly reduced the weight of the ovaries and the number of secondary and tertiary follicles, and corpora luteum. The number of atretic follicles as well as primary and pre-ovulatory follicles was not affected. Granulosa cells in the secondary follicles of treated rats had small nuclei with a reduced number of AgNORs. Significant reduction of the endometrium thickness, number of endometrial glands and the infundibulum epithelium height was observed.

Brucella ovis lacking a species-specific putative ATP-binding cassette transporter is attenuated but immunogenic in rams.

Ovine brucellosis caused by Brucella ovis is considered one of the most important reproductive diseases of rams worldwide. This study aimed to characterize the kinetics of infection of a ΔabcAB B. ovis mutant strain in rams. Twelve 1-year-old crossbred rams were used. Six rams were challenged with 2 mL of a suspension containing 1.2×10(9) CFU/mL of B. ovis strain ATCC25840 (wild type) by intraprepucial inoculation and additional 50 μL in each conjunctival sac of a suspension containing 1.2×10(10) CFU/mL of the same strain. The other six rams were challenged with an equivalent number of CFU of the mutant strain ΔabcAB B. ovis through the same routes. Serum samples for serology and semen and urine samples for bacteriologic culture and PCR were collected weekly during 24 weeks. At 24 weeks post infection, tissue samples were collected for bacteriologic culture and PCR. All rams inoculated with wild type or the ΔabcAB strain seroconverted at the fourth week post infection, remaining positive up to the 16th week post infection. PCR and bacteriology demonstrated that only rams inoculated with the wild type strain shed the organism in semen and urine. Lymphocytes from rams inoculated with wild type or ΔabcAB B. ovis had significantly higher proliferation in response to B. ovis antigens when compared with unstimulated controls. Tissue bacteriology and PCR detected B. ovis in all rams challenged with the wild type strain, whereas only one ΔabcAB-infected ram had a positive iliac lymph node sample by PCR.

Treatment of Bothrops alternatus envenomation by Curcuma longa and Calendula officinalis extracts and ar-turmerone

It was investigated the efficiency of two extracts of plants and one fraction of their properties against the local effects of bothropic envenomation. Bothrops alternatus venom (1.25µg) diluted in 100µl of sterile saline solution was inoculated (intradermally) into the shaved dorsal back skin of 30 New Zealand rabbits. The animals were divided in six groups receiving the following treatments: group I: subcutaneous application of Curcuma longa extract (1.0ml); group II: topic treatment of Curcuma longa hydroalcoholic extract (1.0ml); group III: topic application of ar-turmerone in vaseline (1.0g); group IV: topic application of Curcuma longa methanolic extract (1.0ml); group V: topic application of Calendula officinalis ointment (1.0g); group VI: topic application of saline (1.0ml). These treatments were done at 30 minutes, and at 2, 4, 24 and 72 hours after venom inoculation. Intensity of local edema, hemorrhagic halo and necrosis were evaluated until 168h after that. Additionally, seven days after the Bothrops venom inoculation, blood was collected from heart with and without EDTA (10%) for hemogram and biochemical parameters (total protein, blood urea nitrogen, creatinine, and fibrinogen) and all the animals were anesthetized, sacrificed by ether inhalation and submitted to necropsy. Fragments of tissues were taken for histopathological evaluation. The most efficient treatment for inhibition of edema, necrosis and local hemorrhage after Bothrops alternatus venom was the topic application of ar-turmerone.