Comparative study of DNA extraction methodologies from goat sperm and its effects on polymerase chain reaction analysis

Successful DNA extraction is indispensable for molecular methods based on polymerase chain reaction (PCR); however, goat sperm DNA extraction is limited. Thus, the aim of this study was to evaluate three methods to extract DNA from goat sperm for use in PCR. Eight goat semen pools were used for DNA extraction by using the DNeasy Blood & Tissue Kit, phenol-chloroform, and Chelex-100 methods. DNA samples were analyzed spectrophotometrically to determine the DNA concentration and purity, visualized on 0.8% agarose gel, and used at different amounts (150, 100, 50, 10, and 1 ng) for PCR with electrophoresis, followed by 1.5% agarose gel electrophoresis. The quantity of DNA extracted with Chelex-100 was higher (P < 0.05) than that obtained with either the DNeasy Blood & Tissue Kit or the phenol-chloroform method, with the phenol-chloroform method yielding a greater quantity (P < 0.05) than the kit. The DNeasy Blood & Tissue Kit produced a higher (P < 0.05) purity product than the Chelex-100 method, and all samples obtained by the three protocols were positive for DNA, as assessed by electrophoresis. All of the different concentrations of DNA produced by these methods were amplified by PCR, although for DNA produced by the phenol-chloroform method, PCR was only possible after complementary purification. In conclusion, the Chelex-100 method is cheap, secure, simple, fast, and effective, and is a potential tool for extracting goat sperm DNA without limitations in PCR.

Genetic diversity and differentiation of five Cuban cattle breeds using 30 microsatellite loci

Conservation and improvement strategies in farm animals should be based on a combination of genetic and phenotypic characteristics. Genotype data from 30 microsatellites were used to assess the genetic diversity and relationships among five Cuban cattle breeds (Siboney de Cuba, Criollo Cubano, Cebú Cubano, Mambí de Cuba and Taíno de Cuba). All microsatellite markers were highly polymorphic in all the breeds. The expected heterozygosity ranged from 0.67 ± 0.02 in the Taíno de Cuba breed to 0.75 ± 0.02 in the Mambí de Cuba breed, and the observed heterozygosity ranged from 0.66 ± 0.03 in the Cebú Cubano breed to 0.73 ± 0.02 in the Siboney de Cuba breed. The genetic differentiation between the breeds was significant (p < 0.01) based on the infinitesimal model (F(ST)). The exact test for Hardy-Weinberg equilibrium within breeds showed a significant deviation in each breed (p < 0.0003) for one or more loci. The genetic distance and structure analysis showed that a significant amount of genetic variation is maintained in the local cattle population and that all breeds studied could be considered genetically distinct. The Siboney de Cuba and Mambí de Cuba breeds seem to be the most genetically related among the studied five breeds.

Evaluation of an integrated orbital tissue expander in an anophthalmic feline model

PURPOSE

To evaluate the anatomical effects and tissue biocompatibility in a feline model of an integrated orbital tissue expander (OTE) designed to stimulate bone growth in an anophthalmic socket.

DESIGN

An animal study was performed in cats to assess orbital bone growth with and without an OTE.

METHODS

The OTE is an inflatable (0.5 to >6.0 cm(3)) polymeric globe sliding on a titanium T plate secured to the lateral orbital rim with screws. Eight cats had left eye enucleation at age two weeks, with five orbits receiving an OTE and the remaining three serving as nonimplanted controls. Serial transconjunctival implant inflation was performed by injecting normal saline solution into the OTE to a final volume of 3.5 ml. Serial computed tomographic scans were obtained to assess socket growth. All eight cats were euthanized at 18 weeks and dry skulls prepared. The effective orbital volume was measured by inflating an OTE in the orbit of a dry skull until it filled the cavity completely.

RESULTS

Three cats periodically scratched open the tarsorrhaphy and conjunctiva to rupture the OTE, which resulted in implant exchanges. At 18 weeks, the OTE expanded orbital volume was approximately 18% smaller than the normal contralateral side. In the control animals, the anophthalmic orbital volume was approximately 66% smaller than the contralateral orbit. Histopathology of orbital tissues showed no evidence of foreign body reaction.

CONCLUSIONS

This proof-of-concept pilot study demonstrated implant efficacy in cats, and no implant-related adverse effects were observed. OTE has the potential to stimulate bone growth in human anophthalmic orbits.

Tracheal stenosis: the long and the short of it

PURPOSE

The aim of this study was to present slide tracheoplasty as the procedure of choice for tracheal stenosis. From 1990 through 1997, patients referred to University of California, San Francisco for tracheal stenosis were managed by resection and anastomosis. During this period, other centers reported successful use of slide tracheoplasty and, from 1998 to 1999, we performed 3 slide tracheoplasties in addition to 3 more resection and anastomosis procedures.

METHODS

Between 1990 and 1999, 9 patients with tracheal stenosis of varying lengths underwent surgery at the University of California, San Francisco. They were treated surgically with either resection and anastomosis or with slide tracheoplasty.

RESULTS

Two of the 6 patients treated by resection and anastomosis had an anastomotic breakdown; all 3 patients undergoing slide tracheoplasty did not have anastomotic problems. Technically, a slide tracheoplasty has only one half the tension distributed over an oblique anastomosis that is more than the circumferential length of a resection and anastomosis approach.

CONCLUSION

Based on these results, a slide tracheoplasty may be the procedure of choice for tracheal stenosis, whether long or short.