Description and comparison of brain distribution of oxytocin receptors in Rhabdomys pumillio and Rhabdomys dilectus.

Oxytocin receptor (OXTR) distribution in the brain has been associated with different reproductive and social strategies of species. Rhabdomys pumilio (R. pumilio) and Rhabdomys dilectus (R. dilectus) are two sister rodent species that live in large/medium (but flexible) or small (mostly solitary) social groups respectively. In this study, we describe and compare the distribution of OXTR in these two species. OXTR binding in the brain of R. pumilio (8 females and 5 males) and R. dilectus (8 females and 5 males) adults was determined using autoradiography. Our results revealed significant differences in the nucleus accumbens, diagonal band, medial preoptic area, lateral habenula, superior colliculus, periaqueductal area and anterior paraventricular nucleus (higher in R. dilectus), and the dorsal lateral septum and anterior bed nucleus of the stria terminalis (higher in R. pumilio). OXTR density in other brain regions, such as the amygdala nuclei and hippocampus, did not differ between the two species. Sex differences were found in the medial preoptic area and ventral region of the lateral septum in R. pumilio (OXTR density higher in males) and in the anterior paraventricular thalamic nucleus, ventromedial nucleus of the hypothalamus and basolateral amygdala of R. dilectus (OXTR density higher in females). A sex difference in the density of OXTR was also found in the posterior region of the bed nucleus of the stria terminalis, where it was higher in males than in females of both species. This study shows species-specific brain distribution of OXTR in R. pumilio and R. dilectus that are unique, but with similarities with other polygynous or promiscuous rodent species that live in variable size groups, such as R. norvergicus, C. sociabilis, S. teguina and M. musculus.

Development of temperature correction equations for bioelectrical impedance analysis models for brook trout Salvelinus fontinalis.

The objective of this study was to establish the relationships between bioelectrical impedance analysis (BIA) measures (resistance and reactance) and temperature and to determine if corrections improve BIA models for brook trout Salvelinus fontinalis when used over a wide range of temperatures. Both resistance and reactance significantly decreased as temperature increased. Application of temperature corrections to BIA models attempting to predict per cent dry mass reduced root-mean-squared error by an average of 32%. Researchers taking BIA measures on fishes in the field where temperature varies will need to correct resistance and reactance to the temperature at which the BIA model was developed for successful predictions of per cent dry mass to be possible. This study presents a clear description of methods that can be used to developed temperature correction equations so that future researchers can use BIA in any field setting and increase the accuracy of BIA-based estimates of per cent dry mass.

Genome-scale cloning and expression of individual open reading frames using topoisomerase I-mediated ligation.

The in vitro cloning of DNA molecules traditionally uses PCR amplification or site-specific restriction endonucleases to generate linear DNA inserts with defined termini and requires DNA ligase to covalently join those inserts to vectors with the corresponding ends. We have used the properties of Vaccinia DNA topoisomerase I to develop a ligase-free technology for the covalent joining of DNA fragments to suitable plasmid vectors. This system is much more efficient than cloning methods that require ligase because the rapid DNA rejoining activity of Vaccinia topoisomerase I allows ligation in only 5 min at room temperature, whereas the enzyme's high substrate specificity ensures a low rate of vector-alone transformants. We have used this topoisomerase I-mediated cloning technology to develop a process for accelerated cloning and expression of individual ORFs. Its suitability for genome-scale molecular cloning and expression is demonstrated in this report.

Postpartum pyometra: a case report.

Pyometra is an uncommon result of endometritis. The diagnosis of pyometra is made when a collection of pus is found within the endometrial cavity. Antibiotic administration and drainage of the pus are essential to resolve this condition. A report of a case of pyometra is presented and a technique for drainage is described. This case demonstrates the use of office-based diagnostic ultrasonography to narrow the differential diagnosis and guide the drainage procedure, as well as the use of simple ingenuity to improve patient care.

Obstetric ultrasound by family physicians.

Obstetric ultrasound examination is a useful diagnostic procedure for family physicians who select appropriate equipment, observe indications, understand limitations, and work toward performance mastery. The knowledge obtained during an examination assists clinical decision making and reduces liability. This is particularly true for rural and underserved communities where family physicians provide the majority of prenatal and comprehensive perinatal care. Mastery of obstetric ultrasound techniques can also lead to developing amniocentesis skills and serve as an aid to external cephalic version. The equipment does not require extensive maintenance and is available at all hospitals. Many offices and group practices have found purchase of this equipment to be cost effective. Based on clinical experience in family practice and a review of the medical literature, an approach to skill acquisition and quality assurance is described.

Relationship between liver tumors and age in brown bullhead populations from two Lake Erie tributaries.

We compared liver tumor frequencies, and age and length characteristics of brown bullheads (Ictalurus nebulosus) of greater than 250 mm total length from two Lake Erie tributaries. Bullheads taken from Old Woman Creek (n = 144) had no grossly observable liver tumors, while those collected in the highly industrialized Black River (n = 532) had a 30% frequency of grossly visible liver tumors during 1981-1982. Liver lesions diagnosed histologically in a randomly collected sample (n = 125) of brown bullheads from the Black River included both biliary and hepatic lesions, with cancerous neoplasms occurring in 38.4% of the fish. Black River bullheads of combined ages 4 and 5 had a significantly (p less than or equal to 0.05) greater prevalence of biliary carcinomas (35.5%) than those of ages 2 and 3 combined (18.4%). Biliary carcinoma was significantly more prevalent than hepatocellular carcinoma in age 4 fish (sexes combined) and in males of ages 3 and 4. The prevalence of hepatocellular carcinoma was significantly higher in females than in males. Age distributions of bullheads differed significantly between the two sites, while length distributions were similar. No brown bullheads of ages 6 or 7 were collected in the Black River, while these age groups composed 18% of the catch in Old Woman Creek. Brown bullheads of age 5 were almost six times more numerous in the Old Woman Creek than in Black River collections. These age and length distributions are consistent with the hypothesis that brown bullheads in the Black River were subjected to an age-selective mortality associated with high prevalences of liver carcinoma.