Temporary obstructive effect of human cervical mucus on spermatozoa throughout reproductive life: a scanning electron microscopic study

The Use of NFP When Pregnancy Is Contraindicated?

The Sacred Congregation for the Doctrine of the Faith has declared the moral liceity of hysterectomy when certain medical criteria are met but does not exclude other options, "for example, recourse to infertile periods or total abstinence." Consequently, there may be couples who prefer to use natural family planning (NFP) methods. We shall refer to these in this article. The efficacy of NFP methods is determined by knowing the day of ovulation. To that end, three parameters are used: the presence and consistency of cervical mucus, measurement of the basal body temperature, and the determination of particular hormones in urine. Of the NFP methods used, the so-called sympto-thermal method seems to be the most effective. It has been concluded that the postovulatory or luteal phase of the female menstrual cycle is the safest time to avoid pregnancy if the couple has sexual intercourse during this period. Nevertheless, the use of NFP methods has limitations if the length of the cycles varies, there are fluctuations in the basal temperature, or when there are vaginal infections. Urinary hormone levels can also be altered by the use of antibiotics or psychotropic drugs. In general, however, it can be concluded that NFP methods, if used in the conditions mentioned herein, offer a high degree of reliability, similar to that of artificial contraceptive methods. Accordingly, if pregnancy must be avoided in the medical circumstances to which the Congregation for the Doctrine of the Faith refers, NFP methods can effectively replace hysterectomy, thereby circumventing the medical difficulties of this practice.

Summary

The Sacred Congregation for the Doctrine of the Faith has declared the moral liceity of hysterectomy when certain medical criteria are met but does not exclude other options, "for example, recourse to infertile periods or total abstinence." Consequently, there may be couples who prefer to use natural family planning (NFP) methods. We shall refer to these in this article. In general, it can be concluded that NFP methods, if used in the conditions mentioned herein, offer a high degree of reliability, similar to that of artificial contraceptive methods. Accordingly, if pregnancy must be avoided in the medical circumstances to which the Congregation for the Doctrine of the Faith refers, NFP methods can effectively replace hysterectomy, thereby circumventing the medical difficulties of this practice.

How to design the surface of peptide-loaded nanoparticles for efficient oral bioavailability?

The oral administration of proteins is a current challenge to be faced in the field of therapeutics. There is currently much interest in nanocarriers since they can enhance oral bioavailability. For lack of a clear definition, the key characteristics of nanoparticles have been highlighted. Specific surface area is one of these characteristics and represents a huge source of energy that can be used to control the biological fate of the carrier. The review discusses nanocarrier stability, mucus interaction and absorption through the intestinal epithelium. The protein corona, which has raised interest over the last decade, is also discussed. The universal ideal surface is a myth and over-coated carriers are not a solution either. Besides, common excipients can be useful on several targets. The suitable design should rather take into account the composition, structure and behavior of unmodified nanomaterials.

Self-identification of the clinical fertile window and the ovulation period

OBJECTIVE

To assess the sensitivity and specificity of the self-identified fertile window.

DESIGN

Observational study.

SETTING

Not applicable.

PATIENT(S)

A total of 107 women.

INTERVENTION(S)

Women recorded cervical mucus observation and basal body temperature daily while undergoing daily ovarian ultrasound.

MAIN OUTCOME MEASURE(S)

The biological fertile window, defined as the 6 days up to and including the day of ovulation; and the 2-day ovulation window, defined as the day before and the day of ovulation.

RESULT(S)

The self-identification of the biological fertile window by the observation of any type of cervical mucus provides 100% sensitivity but poor specificity, yielding a clinical fertile window of 11 days. However, the identification of the biological fertile window by peak mucus (defined as clear, slippery, or stretchy mucus related to estrogen) yielded 96% sensitivity and improved specificity. The appearance of the peak mucus preceded the biological fertile window in less than 10% of the cycles. Likewise, this type of mucus identified the ovulation window with 88% sensitivity.

CONCLUSION(S)

These results suggest that, when perceived accurately, more accurate clinical self-detection of the fertile window can be obtained by identification of peak mucus. This may improve efforts to focus intercourse in the fertile phase for couples with fertility concerns.

Ultrastructural and Rheological Properties of Bovine Vaginal Fluid and its Relation to Sperm Motility and Fertilization: a Review

The tubular genital organs of the mammalian female reproductive tract provide different luminal microenvironments that can act as an aid or a barrier to gamete transport and the first steps of embryonic development. The mechanism of sperm transport through the genital tract has not been fully established but, first of all, sperm cells encounter and need to overcome mucous-like secretions to reach the site where fertilization occurs. One of these secretions, vaginal fluid, is a complex biological product, which is mainly derived from cervical mucus. In this review, we focus on recent studies that describe the relationships between the ultrastructural and rheological properties of bovine vaginal fluid and sperm motion. In the light of this, we propose bovine vaginal fluid as a morphofunctional model for the study of sperm transport in mammals.

The pin-hole cervical os; a small fertility problem

24 women with a so-called pin-hole cervical os during the pre-ovulatory phase of the menstrual cycle were detected in a group of 850 infertile couples. This cervical condition is rarely seen and is often combined with extreme oligomucorrhea and poor cervical mucus qualities. Sperm quality was so poor in four couples that they were excluded. Nine women were likely to have been exposed to diethylstilbestrol (DES) in utero. The pregnancy rate in this group was poor, only two pregnancies by coitus and none by intra-uterine AIH. In the other eleven women there was a strong correlation between a good result of the post-coital test (PCT) and the chance to achieve pregnancy. Four of the eight women with a good result of the PCT became pregnant by coitus. The three women with a poor result of the PCT became pregnant by intra-uterine AIH. It is possible that the fertility prognosis of a woman with a pin-hole cervical os during the pre-ovulatory phase of the menstrual cycle is unfavourably influenced by DES exposure in utero. A pin-hole cervical os in the pre-ovulatory phase of the menstrual cycle, without DES exposure, has probably no influence on fertility.

Pathogenetic implications of ultrastructural findings in Campylobacter pylori related gastroduodenal disease

There is now substantial evidence that Campylobacter pylori (Cp) is able to colonize the gastroduodenal mucosa and is responsible for active chronic gastritis, its role in duodenitis, gastric ulceration and duodenal ulceration is still under debate. Cp has a lot of characteristics which are prerequisites for a pathogen: the typical S-shape, the corkscrew-like movement and the powerful urease and protease enzymes. These features allow a rapid movement through the mucous layer to permit access to the apical membranes of the surface mucous cells. There they adhere directly to the membranes and induce several ultrastructural alterations: degeneration of microvilli, depletion of mucous granules and an increase in sialic-acid rich glycoproteins in the apical part of the cytoplasma. Cp weakens the tight-junction complex and is found between the cells and sometimes intracellularly. Cp is phagocytized by invading polymorphonuclear leukocytes and causes an intense inflammatory response. These observations clearly demonstrate pathological alterations which in the cellular level induced by Cp with the result of a disrupted mucosal barrier of the stomach and the duodenum.

Improvement of human ovulatory cervical mucus by alpha-amylase. Effect on spinability and crystallization in vitro

Alpha-amylase can modify ovulatory cervical mucus in vitro, changing both its structure and an essential rheological parameter, spinability. After 5 min at alpha-amylase concentrations above 4.6 mg/ml, spinability was greatly reduced or even non-existent because of the total liquefaction of the mucus. These concentration levels also induced breakdown of the solid phase of the hydrogel, producing more or less marked abnormalities in mucus crystallization after air drying. In the presence of the highest alpha-amylase concentrations (greater than or equal to 37.5 mg/ml) dendrites could not be formed and only sodium chloride crystals were visible at high magnification under a scanning electron microscope. In the 75 to 1.2 mg/ml concentration range, where alpha-amylase has a significant action on cervical mucus, there was an overall decrease in average spinability as the enzyme concentration fell. The action of the enzyme was greater after 10 min than after 5 min reaction time. For the 10-min reaction time interval, the activity could be adjusted using a squared polynominal regression, whereas for the 5-min reaction time interval a linear regression was a suitable model of enzymatic activity. In the 4.6 to 1.2-mg/ml concentration range, adjustment on a linear model showed that there was a significant effect of alpha-amylase concentration and reaction time on mucus spinability. Statistical analysis of the dose-effect data was compatible with the structural changes in dried cervical mucus demonstrated by scanning electron microscopy.

Treatment of cervical mucus with lectins: effect on sperm migration

Treatment of midcycle human cervical mucus with the lectins Ulex europaeus agglutinin I (UE), wheat germ agglutinin (WGA), and peanut agglutinin (PA) did not alter the ability of spermatozoa to enter and migrate through the mucus. These lectins form glycoconjugates by binding to L-fucose (UE), N-acetylglucosamine and sialic acid (WGA), and D-galactose and D-galactose-(1-3)-D-N-acetylgalactosamine (PA), sugars that are present in the carbohydrate side chains of the mucus glycoproteins (mucins). Ricinus communis, with high affinity for D-galactose and N-acetylgalactosamine, did cause a significant decrease in sperm migration but only within the mucus (not at the sperm-mucus interface); this may have been because of an effect on sperm motility. These sugars are thought to be important for the secondary structure of the glycoproteins and for the cross linking between the mucins that produce the rheologic properties of cervical mucus. However, it appears that interference with the sugars by lectin binding does not significantly alter the ability of spermatozoa to migrate through cervical mucus.

Experimental study of cervical blockage induced by continuous low-dose oral progestogens

An investigation correlating scanning electron microscopic observations with sperm penetration tests carried out on cervical mucus under the influence of low-dose continuous progestogen (Norgestrienone) is presented. The results demonstrate that such type of contraceptive is involved in drastic alterations of mid-cycle cervical mucus at the macromolecular level. The meshwork which constitutes the infrastructure of the cervical secretion appears to be greatly tightened as a result of the treatment, thus giving the woof a general appearance typical of cervical mucus in the late luteal phase. The immobilizing effect of such modified mucus on spermatozoa is demonstrated and the duration of effectiveness after the administration of a last pill on the morning of day 13 is determined.