Ultrastructural changes in rat epididymis after vasectomy

Summary Epididymal biopsies from rats that had undergone unilateral or bilateral vasectomies from one to eight months previously were compared with biopsies from their contralateral side or from normal controls to ascertain what ultrastructural changes had occurred. After vasectomy, spermatozoa appeared to dissolve in the lumen of the caput epididymidis and to be absorbed by the principal cells. About 5 weeks after vasectomy, numerous lamellar accumulations became apparent in the supernuclear region. Their resemblance to lysosomes or residual bodies was confirmed by an acid phosphatase reaction. After 10 weeks, similar lamellar and polymorphic accumulations on the contralateral side of animals with unilateral vasectomies indicated that resorption had also increased on the unligated side.Publication No. 627 of the Oregon Regional Primate Research Center. This study was supported by NIH Grants No. RR-00163 and HD-05969.The author wishes to thank Ms. J. Hren for her excellent technical assistance.     

Primates: Their use in research on vasectomy

Studies based on experimental vasectomies clearly reveal marked species differences in response to vasectomy. In rats, vasectomy invariably results in granuloma formation at the surgical site. In rabbits, immune-complex orchitis develops. Allergic orchitis may also develop in guinea pigs, and the morphological lesions can be adoptively transferred. My co-workers and I have been able to study systematically, biochemically, hormonally, pathologically, and immunologically, primates vasectomized up to 14 years earlier and to compare them with age-matched controls. We have monitored antibody levels in vasectomized rhesus and cynomolgus macaques by sperm-agglutination, sperm-immobilization, and indirect immunofluorescence techniques. Antibodies develop in almost every monkey, in some as early as 10 days after vasectomy. About 50% retain such circulating antisperm antibodies. In men, antibody development is less rapid, and about half of vasectomized men reveal detectable levels. Testicular histopathological studies have revealed detectable levels. Testicular histopathological studies have revealed orchitis, aspermatogenesis, or both, resembling allergic orchitis in most of the vasectomized monkeys and in about one-fourth of the controls. Limited studies of human material reveal some testicular changes. Epididymitis and epididymal granuloma occur exclusively in the vasectomized animals. Use of immunofluorescence has revealed significantly more granular deposits of IgA, IgG, and/or C3 in the basal lamina of the ductus efferens and the caput epididymidis of the vasectomized monkeys. Similar studies on human material have not been done. Both cynomolgus and rhesus macaques have proved to be excellent models for research in atherosclerosis and so have been used to determine whether constant sperm antigen leakage causes immune-complex formation that might result in arteritis and atherosclerosis. Evaluation of the cardiovascular systems from such animals has revealed that vasectomized monkeys have more frequent, more extensive, and more severe arteriosclerosis than age-matched controls. Epidemiological studies are currently under way to determine whether such an effect also occurs in men after vasectomy.     

Ultrasound imaging of reproductive organs and eggs in Galapagos tortoises,Geochelone elephantopus spp

This study demonstrates the efficacy of using ultrasound to determine the presence of ovarian developing, preovulatory, and atretic follicular structures and oviductal eggs in the Galapagos tortoise, Geochelone elephantopus spp. Ultrasound was effective in locating both right and left ovarian structures in 92% (n = 100 ovaries) of the trials. Developing and preovulatory follicles and oviductal eggs were echogenically visualized and had measurements ranging from 18 to 44 mm (n = 93) and 55 to 68 mm (n = 9), respectively. Atretic follicles ranged in size from 10 to 38 mm (n = 10). In one trial with four G. elephantopus, ultrasound observations were validated with the use of laparoscopy. All procedures were accomplished without general anesthesia on a specifically designed restraining table. Ultrasound provides an effective, safe modality for determining the reproductive status of adult female tortoises.     

Distribution and environmental synchronization of the marine insect, Halobates robustus, in the Galapagos islands.

The following three aspects of the biology of the marine insect Halobates robustus were studied, during a two week observation period, at several sites in the Galapagos Islands: distribution, aggregation behaviour and rhythmicity of locomotory activity. H. robustus occurred in highest numbers on the water surface at shores fringed with mangroves. The aggregations of H. robustus varied according to their location and density. Copulating adults formed dense, floating aggregations, which tended to be close to rocks or mangroves. Late instar nymphs were less aggregated and, in lagoons (where there was some shelter from direct tidal forces), were furthest from the shore. In two types of habitat (mangrove-fringed, sandy shores and rocky shores) the aggregations of H. robustus showed a pronounced ability to maintain a floating station in relation to the surrounding environment, irrespective of tidal movements (in one case at 34 m from the nearest fixed objects). Evidence of the ability of the aggregations to maintain station on the water surface was also obtained by comparing the movements of H. robustus with those of floating polystyrene particles, which move passively with wind and tide. Laboratory observations and experiments indicated no clear periodicity in locomotory movements throughout a 24 h period. However, the frequency of encounters between individuals showed two daily peaks, post-dawn and pre-dusk, with fewer encounters during the day and only occasional encounters during the night. By shifting the light-dark cycle it was demonstrated that the daily bimodal rhythm of encounters is triggered by dawn and, since it is not maintained in constant light or dark, an 'hour-glass' mechanism is suggested. The contributions of single adults, of copulating pairs and of immature stages to the overall pattern of activity were also determined. Immature stages did not affect the overall rate of encounters significantly and the interactions between single and copulating pairs of adults appear to have been responsible for the bimodal pattern.     

Life history of the slipper lobster Scyllarides astori Holthuis 1960, in the Galapagos islands, Ecuador

Growth of the scyllarid lobster Scyllarides astori was estimated in the Galapagos Marine Reserve by use of tag-recapture data and analysis of length-frequency distributions. Asymptotic carapace lengths (CL_∞), obtained from Powell-Wetherall plots, were 17.53 cm for males and 16.38 cm for females. A ‘forced’ Gulland-Holt plot gave growth constants (K) of 0.153 yr^− 1 for males and 0.162 yr^− 1 for females. The narrow size distribution suggests that juveniles occupy a different spatial niche and that adult growth is either very slow or that there is a terminal moult. Currently mainly used for local consumption, there is pressure to allow exportation of S. astori on a large scale to continental Ecuador and abroad. However, its slow growth and low abundance point to the need for a cautious approach and the implementation of clear and enforceable regulations in order to ensure the biological and economical sustainability of the population.     

Applications of microsurgery to reproduction in domestic and exotic mammals

Microsurgery and embryo transfer of mammalian embryos have many possible uses for propagation of domestic and endangered species. Techniques and applications of embryo splitting, chimeric cloning, and production of fetal-placental chimeras are discussed, with an emphasis on interspecies transfers.     

Further evidence that deltamethrin-impregnated collars protect domestic dogs from sandfly bites

In many foci of zoonotic visceral leishmaniasis (ZVL), domestic dogs are important reservoir hosts of the causative Leishmania parasites transmitted by phlebotomine sandflies (Diptera: Psychodidae). We tested the protective value of impregnated dog collars (20 g plastic containing deltamethrin 800 mg ai) against Phlebotomus papatasi (Scopoli) sandflies in Iran. For each assay, the dog was sedated and caged in a net with 70-100 wild-caught sandflies overnight (23.30-06.30 hours). Dogs wearing the collars were bitten by approximately 80% fewer sandflies than before collars were fitted, i.e. 51% vs. 11% of hungry female flies exposed. Sandfly mortality rates following 20 h exposure to dogs with collars (18%) or without collars (17%) were not significantly different. Effects of collars were tested when dogs had been wearing them for 8 days. A previous trial against the sandfly P. perniciosus Newstead in France, using smaller dogs, showed that effects of such collars were not fully realized until they had been worn for 2 weeks or more; they remained effective for at least 8 months and killed significant proportions of the sandflies exposed. Present results with P. papatasi, confirming that this simple device provides effective protection against sandflies, are considered sufficiently encouraging to justify a community-wide field trial of deltamethrin-impregnated dog collars against ZVL vector sandflies in Iran.     

Hormonal regulation of fertility in domestic farm species

The diverse techniques used to successfully regulate reproduction in domestic farm species involve both the direct and indirect manipulation of the endocrine system. Rapid advances in our understanding of the endocrine control of reproduction provides for an expansion and improvement of the techniques available to control fertility. A failure to appreciate even subtle species differences in physiological control mechanisms frequently limits the success of otherwise effective treatments. Changes in the social environment, acting through pheromonal signals, and changes in the physical environment such as light and temperature, may be effective in regulating reproductive function. Likewise changes in suckling intensity and nutritional availability can be used to alter the fertility and fecundity of farm species. Direct intervention to modify reproductive activity is practised at all stages of the reproductive cycle. The range of compounds currently used exert their effects at all levels of the reproductive axis and may promote or inhibit the synthesis and release of hormones, as well as their action in target tissues. Regulation of the bioavailability of hormones has also proved to be an effective means of controlling fertility. In contrast to the application of fertility control in the human and in non-domesticated species, in the socio-economic climate of the modern animal husbandry industry, long term control of the timing of reproductive activity may be as economically important as an increase in fertility or fecundity.     

Variation among populations of Galapagos land iguanas (Conolophus): contrasts of phylogeny and ecology

A phylogenetic scheme derived via multivariate analyses of adaptively neutral scale characteristics is compared to patterns of ecological adaptation in body size and shape, hatchling size, clutch size, and reproductive seasonality, in extant populations of Galapagos land iguanas (genus Conolophus). Three groups of land iguana populations are identified, the oldest being the population of Isla Santa Fe, followed by the populations of the central islands (Santa Cruz, Plaza Sur and Baltra), the youngest populations are those of the western islands (Fernandina and Isabela). Patterns of ecological similarity among these populations are not concordant with phylogenetic lineage. Populations most similar in ecological characteristics are often phylogenetically divergent. Adaptation to local conditions by iguana populations is apparently more important than phylogenetic constraint in explaining variation in ecological characteristics. The assumption that phylogenetically closely-related organisms are also ecologically more similar than less closely-related organisms is not supported by this evidence. Some previous studies may have been misled by using ecological characteristics to derive phylogenetic lineages, resulting in circular support of the assumption.     

Eliminatory behaviour of domestic dogs in an urban environment

Although dogs are valuable, indeed essential, members of society, they sometimes cause problems of an aesthetic, environmental or public health nature arising from their eliminatory habits. To identify which kinds of dog are more likely to be responsible for these problems, defaecation and urination by domestic dogs under varying degrees of human control were studied in the field. Observations were made between February 1980 and November 1981 in 2 streets, 2 landscaped parks and 2 large rough grass areas. The dogs most likely to defaecate in these public places were those who were accompanied by their owner, but not restricted by being on a lead. There was also an inverse correlation between the number of visits made by dogs on a lead to, and faeces density in, the study sites. Generally, the dogs responsible for most urination were discovered to be those off rather than on a lead, males rather than females, and pedigree males rather than mongrel males. Explanations of these findings, and suggestions for minimising dog fouling of the environment, are offered.     

Relationships of the Galapagos flora

Joseph Dalton Hooker's pioneer 1847 paper on Galapagos plants and their relationships is a classic in the field of phytogeography. It was the first study of its kind to be published, comparing the islands' flora with island and continental floras elsewhere, hypothesizing on the dispersal mechanisms of the plants, and pointing out anomalies in the inter-island distributions of the native species. These are still three of the primary concerns of contemporary phytogeographers, and the present paper contrasts Hooker's findings with those of today. Despite the accumulation of a large amount of data since his time, many of Hooker's conclusions regarding Galapagos phytogeography remain valid.     

Seals of the Galapagos Islands

The Galapagos archipelago has been colonized by two species of otariid, the fur seal, Arctocephalus galapagoensis , and the sea lion, Zalophus californianus wollebaeki. The former probably arrived from South America and the latter from North America, both by way of periodic incursions of colder water forming the east Pacific corridor. The terrestrial behaviour of both these otariids is affected by the high ambient temperatures in the Galapagos Patterns of breeding behaviour of otariids which lead to intense polygyny and sexual dimorphism appear to be modified. The habit of prolonging lactation, widespread in otariids, is carried to an extreme in the Galapagos fur seal. The reason for this is unclear.     

Frequencies of transferrin types in various breeds of domestic dogs

Plasma transferrin (Tf) types in dogs were studied by a method of horizontal polyacrylamide gel electrophoresis with a 10 % separation gel and a discontinuous buffer system (Tris-citrate-borate, pH 9.0). Samples were analysed from 1127 dogs belonging to 60 different breeds. Tf^B and Tf^c alleles, each in considerably high frequency, were observed in most of the breeds. Tf^A with relatively lower frequency was observed in Beagle, Cocker Spaniel, Doberman Pinscher, German Shepherd, German Shorthaired Pointer, Old Danish Pointer and Poodle. Two rare Tf alleles, Tf^D and the other designated as Tf^E, were observed only in Cocker Spaniel and in Poodle respectively. Basenji (44 samples) and Small Münsterlander (17 samples) showed the highest frequency (0.97) for Tf^C allele while Carelian Bear Dog (19 samples) showed the highest frequency (0.97) for Tf^B allele. In the total material, the frequencies of Tf alleles A, B, C, D and E were found to be 0.0182, 0.5075, 0.4716, 0.0009 and 0.0018 respectively. By using the observed and expected numbers of Tf heterozygotes, the average inbreeding coefficient (F) within breeds was estimated to be 0.14. Six samples of wolf (Canis lupus L.) studied seemed to be of Tf B type. The present study, along with earlier reports, showed that some of the plasma proteins and enzymes (albumin, transferrin, eserine resistant esterase) exhibit considerably more polymorphism than that reported for hemoglobin and some of the red cell and tissue enzymes in the domestic dog.     

Ixodid tick species recovered from domestic dogs in Japan

The species of ixodid ticks (Acari: Ixodidae) recovered from domestic dogs in Japan between September to November 2000 and April to June 2001 were identified. A total of 4122 ticks, including 1624 larvae, 1200 nymphs, 1016 females and 282 males were removed from 1221 dogs during these periods. Haemaphysalis longicornis (Neumann) was the most frequently found (40.3% of dogs), followed by H. flava (Neumann) (16.1% of dogs), Rhipicephalus sanguineus (Latreille) (4.8% of dogs) and Ixodes ovatus (Neumann) (4.1% of dogs). Small numbers of H. hystricis (Supino), H. campanulata (Warburton), H. japonica (Warburton), H. ias (Nakamura and Yajima), I. persulcatus (Schulze), I. nipponensis (Kitaoka and Saito) and Amblyomma testudinarium (Koch) were also recovered. In the spring sample, a total of 1408 ticks (78 larvae, 411 nymphs, 792 adult females and 127 adult males) were recovered from 570 dogs. The autumn sample included a larger proportion of larval stage and fewer adult ticks (1546 larvae, 789 nymphs, 224 adult females and 155 adult males). Haemaphysalis longicornis, H. flava and I. ovatus showed a wide geographical distribution from northern to southern Japan, whereas R. sanguineus were mainly distributed in the subtropical Okinawa prefecture with a few exceptions. Dogs in rural areas more frequently carried H. longicornis, H. flava and I. ovatus than dogs in urban or suburban areas, whereas R. sanguineus was more associated with the dogs in urban/suburban areas. Exposure to a garden was significantly associated with R. sanguineus and exposure to woodland was significantly associated with H. flava and I. ovatus. This is the first systematic survey of canine ticks in Japan.     

Endocrine effects of the GnRH antagonist, acyline, in domestic dogs

Gonadotrophin-releasing hormone (GnRH) antagonists may have a future role in the control of canine reproductive function. In this study, the effects of a single dose of the potent GnRH antagonist, acyline, on serum concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone (T) were evaluated in male dogs. Blood samples were drawn before (Day −1) and after (30, 60, and 90 min, 3, 6, 9, 12, and 24 h, and 3, 6, 9, 14, 22, and 29 d) treatment with acyline (330 μg/kg, sc); serum concentrations of FSH, LH, and T varied throughout the study period (P < 0.01, <0.05, and <0.01, respectively). Gonadotrophins decreased below pretreatment concentrations 60 min after injection, whereas T took 90 min to decrease below baseline (P > 0.05). Follicle-stimulating hormone, LH and T decreased until Day 9, when they reached their nadir at 2.0 ±1.1 ng/mL (P < 0.01), 1.2 ± 0.2 ng/mL (P > 0.05), and 0.5 ± 0.2 ng/mL (P < 0.05), respectively. Both gonadotrophins and T began increasing on Day 14 after treatment, although FSH and T serum concentrations still remained below baseline on that day (P > 0.05). Follicle-stimulating hormone and T rebounded above baseline on Day 29, whereas LH reached concentrations were similar to baseline at this time (P > 0.05). No local or systemic side effects were detected in any dog following acyline treatment. In conclusion, a single acyline treatment safely and reversibly decreased serum gonadotrophin and T concentrations in dogs for 9 d.     

The facilitation of social interactions by domestic dogs

Abstract

Research suggests that dogs can facilitate social interactions, which, in turn, may promote psychological health. This study explored the ability of dogs to facilitate social responses relative to other accompaniments and investigated whether the social catalysis effect is generic or influenced by the appearance of the dog. The behavior of 1800 pedestrians approaching a female experimenter was recorded as a function of the presence of three dogs (Labrador Retriever pup, Labrador adult, Rottweiler adult) and two neutral stimuli (teddy bear, potted plant). The behavior of pedestrians approaching the woman whenever she was alone (control) was also explored. Information was collected on the passers-by’ gender, number of people in the party, type of acknowledgement elicited and length of conversations. More people ignored the experimenter whenever she was alone or with the teddy or plant, than whenever she was walking a dog. The Rottweiler resulted in more nonresponses than the puppy or adult Labrador, who in turn elicited more smiles and verbal responses. Females, and those alone, elicited more smiles and conversations than males, or those in pairs. It is concluded that dogs can facilitate social interactions between adults better than other accompaniments; however, the social catalysis effect is not generic, but dog specific.