Publications by authors named "PM Zavos"

Objective: To assess the efficacy of serial splitting of mouse embryos with respect to blastocyst development.

Design: Prospective study.

Setting: Commercial research facility.

View Article and Find Full Text PDF

This study was designed to compare the developmental potential of individual blastomeres derived from 2-, 4-, 6- and 8-cell mouse embryos cultured with and without zona pellucida (ZP). In the first series, one, three, five and seven blastomeres were biopsied from 2-, 4-, 6- and 8-cell embryos respectively, and inserted individually into empty ZP recipients, leaving the remaining blastomere within its original ZP. In the second series, the same protocol was used except that the biopsied blastomeres were cultured without ZP and compared with the remaining blastomere within its original ZP.

View Article and Find Full Text PDF

This study was conducted to evaluate the preimplantation embryonic potential of adult somatic cells from an infertile man using an interspecies bioassay for quality control and also to create human embryos via somatic cell nuclear transfer (SCNT). Skin tissue was biopsied from infertile man to obtain fibroblast cells. These cells were fused with both enucleated bovine oocytes obtained commercially and human oocytes obtained from his wife.

View Article and Find Full Text PDF

Frozen semen specimens from 22 Holstein bulls representing a wide range of field fertility levels or nonreturn rates (NRR) were used in this study. Semen specimens were thawed at 37 degrees C for a minimum of 30 sec, followed by assessment via a routine semen analysis (RSA) and other sperm functional tests. The RSA was performed by assessing sperm count, motility and morphological characteristics.

View Article and Find Full Text PDF

Aim: To assess the seminal characteristics as well as the sexual behavior of men of various age groups to establish the presence of an aging effect on those characteristics.

Methods: Semen samples were collected from men (n = 792) undergoing in vitro fertilization or intrauterine insemination in cases of female factor infertility only. Samples were collected using a seminal collection device at intercourse and evaluated manually according to World Health Organization (WHO) standards.

View Article and Find Full Text PDF

Objective: To examine the embryonic preimplantation potential of human adult somatic cells by creating interspecies embryos via somatic cell nuclear transfer (SCNT) using bovine oocytes.

Design: Prospective study.

Setting: Research facility of Reprogen.

View Article and Find Full Text PDF

This study was designed to assess the viability and fecundity of semen stored at 5 degrees C for 24 hours using the Bio-Tranz shipping system. Semen specimens were assessed for motility and sperm membrane integrity at the time of collection and 24 hours after storage in the Bio-Tranz. In group 1 (n = 61), specimens were diluted in TYB, processed and used for intrauterine insemination (IUI), leaving an aliquot for storage for 24 hours in the Bio-Tranz.

View Article and Find Full Text PDF

The objective of the current study was to establish a safe, efficient biopsy procedure for embryo splitting using the mouse model for future applications in human assisted reproduction. From mouse embryos at the 2-, 4-, 6- and 8-cell stage, half the number of blastomeres were microsurgically biopsied and transferred into empty mouse zonae pellucidae. Twin embryonic development was monitored during in-vitro culture.

View Article and Find Full Text PDF

This paper reviews the current status of cloning and stem cell research and its application to treating various diseases, particularly cardiovascular disease. Recently new techniques have been developed to isolate embryonic stem cells from preimplantation embryos. These cells are undifferentiated and are therefore able to develop into the cells of whichever organ it is in contact with.

View Article and Find Full Text PDF

Sperm quality and viability can be improved in healthy men with epididymal necrospermia by requesting a second ejaculate 60 minutes after the first specimen is obtained.

View Article and Find Full Text PDF

The use of a protein source such as serum and albumin had been extensively employed as supplements of culture media for handling and culture of gametes and embryos. Protein molecules behave as colloids in solution and contribute to the osmotic pressure of fluids. The interaction of proteins in solution and spermatozoa needs to be assessed in order to determine their possible role in osmoregulation.

View Article and Find Full Text PDF

The purpose of this clinical trial study was to report the outcome of intracytoplasmic injection of round (RS) and elongated (ES) spermatids retrieved from the testis of nonobstructive men. Seven and three cycles using RS and ES injections were performed, respectively. Only one cycle utilizing the late stage of ES (Sd2) resulted in an on-going pregnancy.

View Article and Find Full Text PDF

Aim: To compare the recovery rate of morphologically normal and chromatin condensed spermatozoa from native semen samples using the SpermPrep filtration columns and Percoll gradient centrifugation and to determine the influence of the two processing techniques on fertilization and pregnancy rates in an IVF-ET program.

Methods: Sixteen semen samples obtained from patient's husband were included in this study. Each was divided into two aliquots.

View Article and Find Full Text PDF

The aim of the study was to assess and compare the efficiency of the ZSC-II versus the Sperm Select techniques in preparing human sperm from normozoospermic patients for use in intrauterine insemination and other assisted reproductive technologies. Twenty-five patients were included in the study. Semen was collected at intercourse and processed via 2 sperm preparation methods.

View Article and Find Full Text PDF

Objective: Transport of unprocessed human semen specimens from the production site to distant laboratories for andrological evaluation and clinical use requires the development of proper protocols and devices for the shipment and maintenance of sperm viability during transport. Factors such as maintenance of proper temperature and the specific diluent used are considered to affect the viability of semen specimens during transport. The Bio-Tranz shipper (ZDL, Inc.

View Article and Find Full Text PDF

Objective: Recent developments in the assisted reproductive technology (ART) areas necessitate the use of new and more efficient and acceptable modes of gamete in vitro manipulation techniques. As established via the use of various forms of ART, the natural process of fertilization has been largely bypassed and the gametes are obtained and manipulated outside of the normal means of conception. For the male, improvements in sperm quality have involved the use of various techniques that aim to recover a small percentage of healthy spermatozoa that can be further used for the different ART procedures.

View Article and Find Full Text PDF

The purpose of this study was to formulate Nonoxynol-9 (N-9) into a solid coprecipitate form which can be used in preparing pharmaceutically attractive and nonirritating vaginal controlled-release delivery systems (DDSs) such as gelatin capsules (HGC) and tablets. N-9 was coprecipitated with polyvinylpyrrolidone (PVP) with or without iodine to produce solid powders which were incorporated into either (a) bilayer tablet DDSs which possess a fast- (outer) and slow- (inner core) releasing compartment, and (b) HGC DDSs (named Triad HGC) composed of fast- (outer), intermediate- (granules), and slow- (pellets) releasing compartments. The rates of release of iodine and/or [14C]N-9 from the two DDSs were studied in vitro in phosphate buffer at pH 5.

View Article and Find Full Text PDF

The objective of this study was to develop new techniques for the cryopreservation of washed spermatozoa. Two media (Ham's F-10 and nonthermoprecipitated TEST-yolk buffer [NT-TYB]) containing 7% (v/v) glycerol were compared to semen cryopreservation by adding glycerol directly to the semen. Twenty four men collected a semen specimen each after 4 days of sexual abstinence via the use of a semen collection device at intercourse.

View Article and Find Full Text PDF

Use of the media TEST-yolk buffer (TYB) in semenology today enables the short-term incubation and cryostorage of spermatozoa and its subsequent use in the various assisted reproductive technologies (ART). Preparation of TYB media involves the addition of egg yolk (20% v/v) to a physiological solution of the zwitterion buffers TES and Tris. The TYB is usually thermoprecipitated to remove the majority of the egg yolk globules and other macromolecules from the medium.

View Article and Find Full Text PDF