Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.1 (chymotrypsin)
 10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human follicular fluid collected by laparoscopic oocyte pick-up during IVF was studied with a computer-assisted semen analyser to evaluate the effect of hFF on human sperm motility and velocity. Freshly ejaculated human sperm were washed with phosphate buffered saline and mixed with either PBS or hFF. At various incubation periods of time, hFF increased both sperm motility and velocity as compared with control (P less than 0.01). After incubation of sperm with hFF at 37 degrees C and 5% CO2 in air for 0, 1, 3, 6, and 12 h, the amplitude increase of motility were 49%, 77%, 330%, 2020%, and 3340% when individual control motility was considered to be 100%. The amplitude increase of curvilinear velocity were 43%, 51%, 67%, 152%, 278%, respectively. Comparison of the motility and velocity of the sperm treated with hFF between 0 and 12 h, showed that hFF preserved both motility and velocity in vitro (P less than 0.01). The stimulatory effect of hFF was retained after boiling at 100 degrees C for 30 min, or after being filtered through Amicon membrane cones, but it disappeared if the hFF had been pre-treated with chymotrypsin. However, hFF did not stimulate the motility and velocity of unwashed sperm in freshly ejaculated human semen. A non-dialyzable and heat-stable factor(s) with a molecular weight below 50,000 in hFF may improve and maintain the motility and velocity of washed human sperm. Whether this factor could be used to improve pregnancy rate in assisted reproduction awaits further investigation.
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PMID:Human follicular fluid stimulates motility and velocity of washed human sperm in vitro. 151 76

In this study the solubility to alpha-chymotrypsin of the zona pellucida (ZP) of human oocytes and polyploid embryos obtained during various clinical procedures of assisted fertilisation (IVF, ICSI, cyropreservation) was evaluated. The aim of the study was to determine whether changes in ZP solubility occur during such procedures and whether abnormal solubility could be likened to fertilisation failure. Correlation between ZP solubility and cortical granule (CG) density was also studied. The results showed that ZP solubility varied considerably among germinal vesicle or metaphase oocytes obtained from different subjects, but was essentially identical for the oocyte cohort obtained from individual women. On the basis of ZP solubility metaphase oocytes were subdivided into two classes: class I, average ZP dissolution time +/- SE = 24.1+/-0.9 min, n = 28; and class II, 46.7+/-2.0 min, n = 13. Prolonged ZP dissolution times of metaphase oocytes were significantly correlated with a low in vitro fertilisation rate in sibling oocytes. The zonae of fertilised eggs (polyploid embryos) showed long solubilisation times (IVF: 45.3+/-3.4 min, n = 18; ICSI: 48.9+/-2.7 min, n = 19). ZP solubility of oocytes that failed to fertilise was intermediate between that of class I metaphase oocytes and embryos (unfertilised IVF: 33.0+/-2.7 min, n = 13; unfertilised ICSI: 43.0+/-2.4 min, n = 9). A moderate spontaneous ZP hardening occurred when metaphase oocytes were cultured for 24 h. Finally, cryopreservation of unfertilised oocytes caused hardening of their ZP, with dissolution times that were comparable to those found in fertilised eggs (49.5+/-2.3 min, n = 10). In most cases, an inverse correlation was found between ZP dissolution time and CG density (longer solubilisation times corresponding to lower CG density). ZP hardening caused by cryopreservation, however, was not associated with a significant reduction in CG density in most of the oocytes examined.
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PMID:Zona pellucida solubility and cortical granule complements in human oocytes following assisted reproductive techniques. 1150 39

Men with low hypoosmotic swelling test (HOST) scores (<50%) rarely achieve a pregnancy with intercourse or conventional intrauterine insemination (IUI) or even IVF. The defect seems to be related to a toxic factor attached to the sperm that can be transferred to the zona pellucida, which ultimately interferes with implantation. A small case series showed optimistic pregnancy outcome with treatment of the sperm with low HOST scores with chymotrypsin. However, the live pregnancy rate in 90 subsequent IUI cycles in men whose low HOST scores were improved by chymotrypsin was only 3.3%. IVF with ICSI remains the only highly effective treatment of this disorder.
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PMID:Treatment of sperm with subnormal host scores with chymotrypsin/viable pregnancy after IUI. 1186 29

Males with 100% of their sperm coated by antisperm antibody have a very small chance of achieving a pregnancy by intercourse or conventional intrauterine insemination (IUI). A previous study found that treatment of the sperm with the protein digestive enzyme chymotrypsin improved the efficacy of IUI. The present study was designed to corroborate or refute this previous study and compare efficacy to IVF with ICSI. This time the subjects were an even more difficult group with 100% of the sperm coated by autoantibodies.
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PMID:Effect of treating antibody-coated sperm with chymotrypsin on pregnancy rates following IUI as compared to outcome of IVF/ICSI. 1476 39

In vitro fertilization-embryo transfer seems to be an effective treatment for unexplained infertility. Some IVF centers always perform intracytoplasmic sperm injection in these circumstances being concerned that fertilization failure may occur by conventional oocyte insemination. However, other IVF centers perform intracytoplasmic sperm injection on half of the oocytes and do conventional insemination on the other half. However, if the group with conventional oocyte insemination had a good fertilization rate, in the future intracytoplasmic sperm injection would not be performed. Other IVF centers would inseminate all the oocytes with conventional insemination and not consider intracytoplasmic sperm injection in the future unless there were poor fertilization rates. The aforementioned studies suggest that prior to considering conventional insemination that as a minimum the simple inexpensive hypo-osmotic swelling test be performed and strong consideration also be given to the sperm stress test and SCSA. Similarly, even though IUI is less risky and costly than IVF-ET, there still is a moderate expense and risk involved, especially when superovulation is used. Thus, consideration for performing these tests should also be given even prior to IUI. This is especially important for subnormal HOST scores where pretreatment of the sperm with the protein digestive enzyme chymotrypsin when preparing the sperm has been demonstrated to markedly improve pregnancy rates.
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PMID:Sperm may be associated with subfertility independent of oocyte fertilization. 1586 25