Effects of herbal supplements on milk production quality and specific blood parameters in heat-stressed early lactating cows

The present study explored the influence of supplemental herbal mixtures on cow milk production, quality, and blood parameters in dairy cows under high ambient temperatures. Thirty Holstein cows were randomly assigned into three experimental groups of 10 each. The first control group was supplied with the commercial basal diet, whereas two treatment groups were provided with the commercial basal diet supplemented with 50 and 100 g/head/day of the herbal mixture, respectively. The results showed that the mixture of herbal supplementation did not influence weekly milk production. Milk total fat, triglyceride, and total protein values were not affected (p < 0.05) in cows fed on basal diets supplemented with herbal mixture; however, milk cholesterol was decreased significantly by 100 mg/head/day of the herbal mixture. On the other hand, lactose has increased significantly by adding 100 mg/head/day of herbal mixture. Furthermore, the total cholesterol level in serum was decreased by adding 100 mg/head/day of the herbal mixture, while plasma prolactin, cortisol, GOT, and GPT were unaffected. Regarding fatty acids (C18, C18:1 (c9), 18:1 (c11), 18:2 (c9, c12), 18:2 (t9, t12), and CLA (c9, t11)), there was no significant variation between the groups. Meanwhile, both C19:00 and 18:3 (c6, c9, and c12) were noticeably higher (p < 0.05) in the group that received 100gm, followed by 50 mg, compared to the control. In conclusion, the supplement with a herbal mixture positively affected milk quality by decreasing total cholesterol and increasing lactose, milk fatty acid profile by increasing unsaturated fatty acids content, and plasma cholesterol levels.

Polymorphism of MnSOD (Val16Ala) gene in pregnancies with blighted ovum: A case-control study

BACKGROUND

Blighted ovum is one of the most common reasons for abortion during the first three months of pregnancy. Manganese superoxide dismutase (MnSOD) is an important antioxidant enzyme in the human immune system. The gene is located on 6q25 chromosome and acts on mitochondrial matrix. In the case of mutation or inactivity of this enzyme, mitochondrial and nuclear DNA will severely be destructed. The most common polymorphism of its gene is Val16Ala.

OBJECTIVE

The aim was to investigate a possible mutation in pregnant women who had abortion during the first trimester of pregnancy due to blighted ovum.

MATERIALS AND METHODS

In this case-control study, 34 women were entered as the case and control groups, respectively. Genome DNA was extracted from saliva samples and its genotype was determined using Tetra-primer amplification refractory mutation system polymerase chain reaction technique.

RESULTS

In the case group, 16 (48%) cases had Val/Val genotype, 17 (50%) were heterozygote and had Val/Ala genotype, and 1 (2%) had Ala/Ala genotype. Among controls, 7 (22%) items had Val/Val genotype, 6 (17%) had Val/Ala genotype, and 21 (61%) had Ala/Ala genotype. The frequency of TT, CT, and CC genotypes was 48%, 50%, and 2% in case group and 22%, 17%, and 61% in control group, respectively. Statistical analysis revealed a significant relationship between Val16Ala polymorphism of MnSOD gene and blighted ovum (p= 0.0003).

CONCLUSION

It has concluded that a significant relationship exists between Val16Ala polymorphism of MnSOD gene and blighted ovum.

Effects of Zn²⁺ and Cu²⁺ on loach ovaries and ova development

This study compared the accumulation of Zn²⁺ and Cu²⁺ in the ovaries and ova of loaches under different concentrations of Zn²⁺ (1.00, 2.50 and 5.00 mg/L respectively) and Cu²⁺ (0.10, 0.25 and 0.50 mg/L respectively). The results showed that both Zn²⁺ and Cu²⁺ accumulated in the ovaries, and that the relationship between accumulation and time was linear over 20 days of exposure. The accumulation of the metals in ovaries was closely related to the concentration of exposure in the solutions (P<0.05), and was obviously affected by the time and doses. However, the Cu²⁺ concentration was significantly higher than Zn²⁺ (P<0.05). The development level of ova in the ovaries also correlated with the concentration and exposure period in the Zn²⁺ and Cu²⁺ solutions. This study compared the accumulation of Zn²⁺and Cu²⁺ in the ovaries and ova of loaches under different concentrations of Zn²⁺ (1.00, 2.50 and 5.00 mg/L respectively) and Cu²⁺ (0.10, 0.25 and 0.50 mg/L respectively). The results showed that both Zn²⁺ and Cu²⁺ accumulated in the ovaries, and that the relationship between accumulation and time was linear over 20 days of exposure. The accumulation of the metals in ovaries was closely related to the concentration of exposure in the solutions (P<0.05), and was obviously affected by the time and doses. However, the Cu²⁺ concentration was significantly higher than Zn²⁺(P<0.05). The development level of ova in the ovaries also correlated with the concentration and exposure period in the Zn²⁺ and Cu²⁺ solutions.

Free radicals generation in an in vitro fertilization setting and how to minimize them

Several studies report an increase in both male and female factors in infertility worldwide. In recent years there has been a tremendous increase in couples seeking assisted reproductive technology (ART) procedures in order to have children. However, the success rates of these procedures still remain very low. One of the major contributing factors to the low success rate in ART has been the damage caused by free radicals to the gametes and the developing embryo. The manipulation of gametes and embryos in an in vitro environment when performing assisted reproductive techniques carries the risk of exposure of these cells to supraphysiological levels of free radicals; namely, reactive oxygen species (ROS) and reactive nitrogen species. Oxidative stress can originate from the early steps of ART involving the oocyte, sperm and embryo, as well as in the endometrial environment later on following embryo transfer. The common sources of free radicals in an in vitro fertilization setting include the developing embryo, spermatozoa and leukocytes, semen centrifugation, oxygen partial pressure, light, culture media and cryopreservation/thawing. These free radicals are measured using different techniques, such as the cytochrome C reduction method and chemiluminescence-based techniques. Different efforts are being employed to minimize the excess generation of free radicals in the ART setting, with the aim of improving the success rate, and antioxidant supplementation has emerged as one of the viable routes. Moreover, it is very important to inform ART personnel about the sources of ROS in the laboratory so that they can stop the use of procedures that are deleterious and start to use safer procedures.

One-step collagenase method for zona pellucida removal in unfertilized eggs: easy and gentle method for large-scale preparation

Purpose

Zona pellucida (ZP)-free eggs are often used for studies such as evaluating the interaction of sperm-oolemma. To acquire ZP-free eggs, the most commonly used methods employ acidified Tyrode's solution, enzymatic digestion with a trypsin-like enzyme, or mechanical methods using micropipettes. However, acidified Tyrode's solution and trypsin-like enzymes often damage the oolemma, especially when many eggs are treated at once for mass sample analyses. The mechanical method requires skill, and it is time-consuming to prepare many ZP-free eggs. Therefore, in this study, to establish an easy, reliable method for preparing ZP-free eggs, we examined the ZP digestion method originally reported by Zuccotti et al. (J Reprod Fertil 93:515-520, 1991) that uses collagenase.

Methods

Mouse unfertilized eggs were treated with collagenase and acidified Tyrode's solution to compare the ZP-free rates, the effect on the oolemma, and the two-cell development rates of ZP-free eggs by in vitro fertilization. The effects on the oolemma were gauged by observing the polarity of the transmembrane protein localization of enhanced green fluorescence protein tagged CD9 protein (CD9-EGFP) and using differential interference contrast microscopy.

Results

Collagenase removed the ZP and the cumulus cells from the cumulus oocyte complex. The collagenase method had no influence on the localization of CD9-EGFP, resulting in a high two-cell development rate. Additionally, the collagenase method could exclude low quality eggs with hardened ZP, since collagenase could not digest the hardened ZP.

Conclusions

The one-step collagenase method is an easy preparation method for large numbers of high-quality ZP-free eggs.

Age-related decline in fertility: a link to degenerative oocytes?

OBJECTIVE

To determine whether the age-related decline in fertility is due to degenerative oocytes or to aneuploidy.

DESIGN

Retrospective.

SETTING

Fertility center of a public and tertiary institution.

PATIENT(S)

One hundred fifty-one women (ages 24 to 44 years) undergoing 158 cycles of conventional IVF or IVF with intracytoplasmic sperm injection (ICSI) between January 1993 and December 1995 were divided into three age groups (group 1, < or = 34 years; group 2, between 35 and 39 years; and group 3, > or = 40 years). They were selected on the basis of available oocytes that remained unfertilized after IVF and that had analyzable chromosomes.

INTERVENTION(S)

Standard pituitary down-regulation and ovarian stimulation with FSH and hMG were done for both IVF and ICSI patients. In addition, all patients were given luteal phase support with P, administered orally, via pessaries, or by IM injections from the day of transfer.

MAIN OUTCOME MEASURE(S)

Fertilization rates and pregnancy rates (PRs), and cytogenetic analyses of unfertilized oocytes.

RESULT(S)

Although fertilization rates were not different among women in groups 1, 2, and 3 (50.9%, 49.3%, and 37.9%, respectively), PRs were significantly lower between groups 1 and 3 (43.2% versus 14.3%). A total of 383 oocytes were examined, of which 287 (75%) could be karyotyped. Of these, 201 oocytes showed a normal 23,X karyotype (70%), 40 (13.9%) were aneuploid, 24 (8.4%) were diploid, 12 (4.2%) had structural aberrations, and 13 (4.5%) had single chromatids only. No increase in the aneuploidy rate was detected between groups 1 and 2 (14.8% versus 12.4%). However, highly significant differences in the rate of oocyte chromosome degeneration, characterized by chromosomes splitting into unassociated chromatids, were observed with increasing age (group 1, 23.7%; group 2, 52.0%; and group 3, 95.8%).

CONCLUSION(S)

It seems that the age-related decline in fertility may be due more to degenerative oocytes than to aneuploidy. A decline in the number of oocytes retrieved with age may be of less importance than the decline in oocyte quality. Women in the older age group have a higher chance of achieving pregnancy from ovum-donation programs than by persisting in using their own aged oocytes, which have a very poor prognosis for success.

Vaccination for contraception

Vaccination for birth control has several advantages over currently available methods of family planning and should prove an attractive addition to the contraceptive armamentarium both in developing countries and in a developed country such as Australia. Concerns have been voiced by consumer health advocates that vaccines, like other long acting contraceptive methods, may be abused by health authorities in developing countries and by their use in vulnerable groups such as aborigines in our own country. These concerns need to be recognised and addressed. More difficult to accommodate are the anxieties expressed by feminist groups about the 'loss of control' and 'lack of body awareness' inherent in a method, such as a vaccine, that is relatively easily administered and has no overt side effects. There is no evidence that these concerns are shared by women in general. The antifertility vaccine that will most likely be applied first in family planning programmes is one directed against the pregnancy hormone hCG. A WHO vaccine directed against the C-terminal peptide of beta-hCG provokes a specific and safe immune response and will enter Phase 2 trials in Sweden this year. Subsequent developments with this vaccine will include the replacement of the current emulsion vehicle by a delivery system based on biodegradeable microspheres which will give a more sustained antigen release and duration of effectiveness.

The contraceptive potential of fertilization: a physiological perspective

Several separate events of the fertilization sequence (sperm capacitation, regulated sperm transport in the oviduct, sperm-cumulus interaction, sperm-zona binding, the acrosome reaction, zona penetration, gamete fusion) represent points at which conception might be preventable. Each is considered variously with reference to its biological significance, what is known about the mechanisms involved, the issues that remain to be resolved, and the prospects for specific inhibition.

The influence of the post-Chernobyl fallout on birth defects and abortion rates in Austria

OBJECTIVES

We analyzed the influence of the radioactive fallout after the Chernobyl disaster on the rate and regional distribution of birth defects and abortion rates in southern Austria.

STUDY DESIGN

During 1985 to 1989 a total of 66,743 births was monitored. Twelve sources provided data on 1695 cases of birth defects, 1579 of which were suitable for analysis. All cases were analyzed in terms of their calculated conception date and divided into three main groups according to their vulnerable phase of embryogenesis, spermatogenesis, and oogenesis. To study possible regional changes, the findings were plotted in 17 political subdistricts. The overall abortion rate and the counseling frequency at termination clinics was determined.

RESULTS

No significant changes in the incidence of birth defects, abortion rate, or counseling rate at pregnancy termination clinics were observed.

CONCLUSIONS

Assessing the teratologic potential of low-dose radiation is difficult and requires adequate grouping of birth defects, sufficient baseline data, and highly reliable registries.

Contraception

The principle of vaccination for the purposes of fertility regulation is scientifically elegant and socially compelling. Factors such as economic production, convenience of use, relatively long-lasting but reversible protection, low failure rate and the avoidance of mechanical devices or exogenous hormones make this approach a potentially attractive option for family planning programmes in both developing and developed countries. The major efforts in research and development have involved the prospect of active immunization against specific antigens of sperm, oocyte, zygote and early embryo, and the pregnancy hormone human chorionic gonadotrophin (hCG). Several anti-hCG vaccines have entered clinical trials. They operate by preventing or interrupting pregnancy at the peri-implantation stage probably by neutralizing the luteotrophic effect of hCG. The most refined vaccine is one directed against the unique C-terminal peptide on the beta-subunit of hCG. This vaccine provokes antibodies that are specific for hCG and do not cross-react with human luteinizing hormone (hLH). Preclinical studies in baboons and data from a phase I human trial indicate that this method is free of side-effects and provides the promise of a duration of effectiveness of up to 12 months. Future research will optimize the anti-hCG approach, utilize new vaccine delivery systems and broaden the spectrum of target antigens of potential utility for contraceptive vaccines.

Ovarian response in superovulated cycles after suppression with oral contraceptive steroids

The endocrine response to controlled ovarian hyperstimulation was reviewed in 94 women undergoing in vitro fertilization during 114 cycles. The purpose of this review was to evaluate the effect of short-term oral contraceptive suppression on the recovery of pituitary gonadotropin function and subsequent controlled ovarian hyperstimulation. Seventy-three cycles (64%) were adequate for oocyte retrieval. In 41 cycles (36%) hyperstimulation was discontinued. The serum 17 beta-estradiol value in women with a poor response was 57 +/- 50 pg/ml on day 8 compared with 376 +/- 334 pg/ml in the women who completed in vitro fertilization (p less than 0.05). The majority of women (84.2%) had a prompt response to controlled ovarian hyperstimulation after short-term oral contraceptive suppression. Most discontinuations were due to dominant follicle selection or luteinizing hormone surge and not to oversuppression by short-term oral contraceptives. Clinical pregnancies occurred in 15 women (20.5% of harvests).

Evaluation of human sperm-zona pellucida tight binding by presence of monoclonal antibodies to sperm antigens

Characterized WHO monoclonal antibodies (MAbs) to human sperm antigens were evaluated as to whether they inhibited sperm-zona pellucida tight binding as assessed by the hemizona assay (HZA). Of the 26 MAbs tested, only one inhibited zona binding. The whole sperm-specific MAb inhibited zona binding by 70%. The MAb also caused strong agglutination. Two procedures, Sephadex column chromatography and papain digestion, were used to determine whether agglutination or steric hindrance was a factor in the capability of MAb to inhibit zona binding. However, inhibition remained comparable to previous results. The MAb did not prevent capacitation, nor calcium influx and the resulting increase in hyperactivated motility and acrosome reaction. Since its inhibitory influence is not due to agglutination factors, steric hindrance or prevention of normal pre-fertilization maturation, the MAb may be blocking a portion of the zona binding receptor and may be useful in elucidating sperm antigens important to sperm-egg interaction. The approach used in this study allows definition of sperm surface antigens involved in zona pellucida binding.

The WHO Task Force on Vaccines for Fertility Regulation. Its formation, objectives and research activities

Over the past 18 years, the WHO Task Force on Vaccines for Fertility Regulation has been supporting basic and clinical research on the development of birth control vaccines directed against the gametes or the preimplantation embryo. These studies have involved the use of advanced procedures in peptide chemistry, hybridoma technology and molecular genetics as well as the evaluation of a number of novel approaches in general vaccinology. As a result of this international, collaborative effort, a prototype anti-HCG vaccine is now undergoing clinical testing, raising the prospect that a totally new family planning method may be available before the end of the current decade.

Epidemiological studies of natural family planning

The prevalence of the use of natural family planning (NFP) can be estimated from sample surveys of married women in the reproductive ages (MWRA). Surveys in developed and developing countries during the past decade indicate that the prevalence of NFP use varies from 0 to 11%. In addition, if one considers NFP use in relation to other contraceptive methods, the percentage of all current contraceptors who use NFP varies from 1 to 35%. This suggests that NFP is an important method in certain countries. Pregnancy rates for NFP vary widely, but most reliable studies report 1-year life-table pregnancy rates between 10 and 25/100 woman-years. The Billings ovulation method consistently has higher pregnancy rates than the sympto-thermal method and NFP users generally have among the highest pregnancy rates compared to other methods. The major safety issue concerning NFP is the risk of adverse pregnancy outcomes associated with aged gametes. There are suggestions from a number of investigations that conceptions distant from ovulation have a higher risk of spontaneous abortion and a higher proportion of male births. The findings with respect to birth defects or multiple pregnancies are less consistent, although some studies have reported an increased risk of chromosomal anomalies.

New insights on the mode of action of intrauterine contraceptive devices in women

To gain a better understanding of the mechanism of action of intrauterine devices (IUDs), a search was made for ova in the genital tracts of 115 women using no contraception and of 56 women using IUDs, all of whom volunteered for study in conjunction with surgical sterilization. Ova were recovered from tubal flushings between 48 and 120 hours after the midcycle peak of luteinizing hormone in 39% of the IUD users compared with 56% of women in the control group (0.05 less than P less than 0.10). This suggests an action of the IUD before the ovum reaches the uterus. Eggs with a microscopic appearance consistent with fertilization were recovered from the fallopian tubes of half of the women using no contraception who had intercourse within the fertile period of the reproductive cycle and from whom ova were recovered. In contrast (P less than 0.01), no eggs with this appearance were recovered in IUD users who had intercourse within the fertile period. No ova were recovered from the body of the uterus of any of the IUD users. Fertilized ova are less likely to reach the uterine cavity containing an IUD. Thus, the principal mode of IUDs is by a method other than destruction of live embryos.

The etiology of ectopic pregnancy

The cause of ectopic pregnancy is associated with two major categories: the integrity of the oviduct and the quality of the fertilized ovum. Several conditions that alter the tubal transport system include inflammatory insults, intrauterine devices, surgical manipulation, tubal ligations, salpingitis isthmica nodusa, DES exposure, and induced abortions. Risk factors that may theoretically alter ovum quality or the hormonal environment include ovulation induction, fertilization in vitro, delayed ovulation, and transperitoneal ovum migration. As we continue to investigate the fallopian tube and the fertilized ovum as unique entities, our knowledge will increase about the cause of ectopic gestations.

The program for in vitro fertilization at Norfolk

Several aspects of the program of in vitro fertilization (IVF), or, as it is called in Norfolk, the program for the Vital Initiation of Pregnancy (VIP), have been or are in the process of publication. However, because there has been no overall account, it seems appropriate to give a brief report of a general nature covering the period from the beginning of the effort in late February 1980 through December 31, 1981. Although minor changes were constantly made in the protocol, there were two major revisions. Therefore, a discussion of the program during three distinct periods, i.e., 1980, 1981-Phase I, and 1981-Phase II, is necessary. During 1980 and 1981 all patients had either no fallopian tubes or irreparable tubes.

Results of laparoscopic recovery of preovulatory human oocytes from nonstimulated ovaries in an ongoing in vitro fertilization program

The technique and results of 50 laparoscopies performed on sterility patients to obtain mature oocytes from Graafian follicles with a view to carrying out in vitro fertilization are described. In 32% of all laparoscopies and in 52% of all punctured follicles it proved possible to obtain a mature oocyte. Different diameters of puncture needles as well as different suction intensities are compared. As a result of increasing experience and improved technique, the exact time for the intervention was correctly determined in 92% of cases. The recovery rate for oocytes was also increased to 58% with respect to laparoscopies carried out.

Recovery of preimplantation blastocysts in the squirrel monkey by a laparoscopic technique

A laparoscopic uterine flushing technique has been developed for the recovery of preimplantation embryos from the squirrel monkey. Fourteen adult female squirrel monkeys were induced to ovulate with 4 or 5 days' treatment with follicle-stimulating hormone (1 mg) followed by human chorionic gonadotropin (HCG) (500 IU). Natural mating with a fertile male or artificial insemination was performed near the time of ovulation. Thirty-six hours and eleven days after HCG administration, the females were laparoscoped to determine whether ovulation had occurred. Under laparoscopic control, 1.2 to 3 ml of warmed saline were flushed through the uterine lumen 4 to 7 and 15 to 17 days after HCG administration. Flushed fluid was recovered with a plyethylene catheter or a Pasteur pipette inserted into the cleaned vagina. Fifty-eight uterine flushings were performed, with an average of 65.4% fluid recovery. Six nonfertilized ova and two preimplantation blastocysts were recovered by this technique.

Further studies of inhibitors of in vitro mammalian oocyte maturation

Studies of luteinizing hormone (LH)-mediated serum inhibition and of follicular fluid and granulosa cell inhibition of in vitro porcine, ewe, and cow oocyte meiotic maturation have been carried out. A porcine serum inhibitor or inhibitors with a molecular weight above 15,000, similar to the ewe and cow serum inhibitor(s), have been demonstrated. An LH-inactivated inhibitor or inhibitors in fluid from medium-sized ewe and cow follicles have been shown and a minimally effective porcine follicular fluid inhibitor has been confirmed. The estimated molecular weight of these inhibitors is below 1,000. Granulosa cells from the three species were not found to be dramatically inhibitory. It is postulated that the follicular fluid inhibitor(s) may be derived from the larger serum molecule(s) by an action of LH within an intermediate cell type.

Histochemical studies of delta5-3beta-, 20lapha- and 20beta-hydroxysteroid dehydrogenases and possible progestagen production in hamster eggs

Hamster eggs at various developmental stages were studied histochemically fro the presence of delta5-3beta-hydroxysteroid dehydrogenase (HSD) (pregnenolone as the substrate and NAD as the cofactor), 20alpha-HSD (20alpha-hydroxypregn-4-en-3-one and NADP) and 20 beta-HSD (20beta-hydroxypregn-4-en-3-one and NAD). All three enzymes were absent from ovarian eggs but were demonstrated in unfertilized and fertilized eggs up to the blastocyst stage. The activities varied only slightly.

From ovulation to blastocyst attachment. A review of early embryonic life in the mouse

The development of the blastocyst from ovulation to implantation is discussed with particular reference to control mechanisms that enable the embryo to attach to the uterine wall, using the mouse as a laboratory model. The physical and chemical changes in the uterus and within the blastocyst are seen as essential steps towards implantation. Evidence that the oestrogen plays a fundamental part in the overall control of these changes is demonstrated. The interrelationship between the hormones of early pregnancy and the uterine production of histamine and cycle AMP is viewed in conjunction with the development of the blastocyst and the decidual changes that occur in the uterus which are essential for nidation.

Immunological aspects of sperm receptors on the zona pellucida of mammalian eggs

Sperm receptor sites on the surface of the zona pellucida are believed to be necessary for fertilization on the mammalian egg. Ovary specific antibodies are known to precipitate the zona pellucida and are also responsible for inhibition of sperm binding and subsequent fertilization. The nature of the proposed receptor sites which are blocked by antibodies are discussed relative to comparable studies in which phytoagglutinins and other agents are used to determine the chemical nature of sperm receptor sites.

Enzyme histochemistry of cultured ovarian cells. I. Histochemistry of porcine preovulatory granulosa cells in culture

Histochemical activity of hydroxysteroid dehydrogenases as well as alkaline and acid phosphatase was investigated in porcine granulosa cells cultured in vitro. Granulosa cells, isolated from preovulatory procine ovarian follicles, during in vitro culture showed activity of enzymes participating in steroid biosynthesis. High activity of delta53betta0H-SDH and G6P-DH as well as the activity of alkaline phosphatase, appearing in the course of culture, could be evidence of progressive luteinization of the cells. Activity of 17beta0H-SDH was lower and exhibited strong fluctuations, similarly low was 20xOH-SDH. Gonadotropic hormones caused the increase of synthesis and accumulation of intracellular lipids. They stimulated alkaline and acid phosphatase, and also the activity of the dehydrogenases. LH had the most visible effect. Estradiol stimulated the activity of acid but not alkaline phosphatase and was not influencing, even lowering the activity of dehydrogenases.

[Ultrastructure function and regulation of the oviduct of the Rana ridibunda (author's transl)]

An investigation has been carried out into the structure, ultrastructure, function and of the oviduct on the adult female of Rana ridibunda. The most important part of the oviduct comprises tubulary glands and a luminal epithelium which is composed of ciliated cells and vesicular cells. The discharge processes of secretory substances were studied. Injection of the mature females with estrogens and progesterone have show that progesterone was the most effective in provoking jelly release. It is probably that in Rana ridibunda the pituitary hormones act on the follicle cells of ripe oocytes, causing them to secrete a progesterone-like hormone which provodes the maturation of the oocytel and jelly release from the oviducal glands.

Spontaneous abortion and aging of human ova and spermatozoa

To test the hypothesis that aging of human gametes within the genital tract increases the chance of abortion, we measured the probabilities of abortion after insemination on a given day of the menstrual cycle in relation to the day of the shift in the basal body temperature in 965 patients. Cases came from family-planning and sterility clinics where basal body temperature and coital records are kept routinely. The probability of abortion diminished significantly (P less than 0.001) as the shift in temperature was approached and the increased to its highest point (24 per cent) three days later. Animal experiments have shown that aging of both spermatozoa and ova before fertilization is accompanied by higher probabilities of abortion. Present evidence indicates that this higher prevalence is also true for human beings.

The penetrability of rabbit ova treated with enzymes or anti-progesterone antibody: a probe into the nature of a mammalian fertilizin

The acrosome reaction of rabbit spermatozoa, an essential prerequiste for penetration of the zona, occurs usually in the vicinity of the egg, suggesting that the rabbit may produce a factor akin to the 'fertilizin' of some invertebrates. Specific inactivation of such a factor should render eggs impenetrable and possibly point to the nature of a 'fertilizin' in mammals. Rabbit eggs with granulosa cells removed were treated for different periods with trypsin, chymotrypsin, neuraminidase or anti-progesterone antiserum, and then transferred alone, or together with control eggs (one group labelled with fluorescein isothiocyanate), to the oviducts of inseminated recipients. Three hours later the eggs were recovered and the experimental and control groups were compared for penetration of the vitellus and for numbers of spermatozoa within the perivitelline space or in the zona pellucida. None of these treatments affected the penetrability of the zona pellucida significantly since the number of spermatozoa within treated eggs in any one experiment was always comparable to that of untreated eggs exposed to the same fertilization environment. If there is a specific substance emanating from or present on the surface of the rabbit egg which induces the acrosome reaction, its activity seems unaffected by trypsin or chymotrypsin; the charged radicals of N-acetyl neuraminic acid or local concentrations of progesterone do not appear to be involved.