SNAREs and traffic.

Bubbles in liquids, soft and squeezy objects made of gas and vapour, yet so strong as to destroy any material and so mysterious as at times turning into tiny light bulbs, are the topic of the present report. Bubbles respond to pressure forces and reveal their full potential when periodically driven by sound waves. The basic equations for nonlinear bubble oscillation in sound fields are given, together with a survey of typical solutions. A bubble in a liquid can be considered as a representative example from nonlinear dynamical systems theory with its resonances, multiple attractors with their basins, bifurcations to chaos and not yet fully describable behaviour due to infinite complexity. Three stability conditions are treated for stable trapping of bubbles in standing sound fields: positional, spherical and diffusional stability. Chemical reactions may become important in that respect, when reacting gases fill the bubble, but the chemistry of bubbles is just touched upon and is beyond the scope of the present report. Bubble collapse, the runaway shrinking of a bubble, is presented in its current state of knowledge. Pressures and temperatures that are reached at this occasion are discussed, as well as the light emission in the form of short flashes. Aspherical bubble collapse, as for instance enforced by boundaries nearby, mitigates most of the phenomena encountered in spherical collapse, but introduces a new effect: jet formation, the self-piercing of a bubble with a high velocity liquid jet. Examples of this phenomenon are given from light induced bubbles. Two oscillating bubbles attract or repel each other, depending on their oscillations and their distance. Upon approaching, attraction may change to repulsion and vice versa. When being close, they also shoot self-piercing jets at each other. Systems of bubbles are treated as they appear after shock wave passage through a liquid and with their branched filaments that they attain in standing sound fields. The N-bubble problem is formulated in the spirit of the n-body problem of astrophysics, but with more complicated interaction forces. Simulations are compared with three-dimensional bubble dynamics obtained by stereoscopic high speed digital videography.

Physics of bubble oscillations

Current status of sperm cryopreservation: why isn't it better?

Role of Cholesterol in Sperm Capacitation

Pregnancy dramatically affects the hypothalamic-pituitary-adrenal axis leading to increased circulating cortisol and ACTH levels during gestation, reaching values in the range seen in Cushing's syndrome (CS). The cause(s) of increased ACTH may include placental synthesis and release of biologically active CRH and ACTH, pituitary desensitization to cortisol feedback, or enhanced pituitary responses to corticotropin-releasing factors. In this context, challenges in diagnosis and management of disorders of the hypothalamic-pituitary-adrenal axis in pregnancy are discussed. CS in pregnancy is uncommon and is associated with fetal morbidity and mortality. The diagnosis may be missed because of overlapping clinical and biochemical features in pregnancy. The proportion of patients with primary adrenal causes of CS is increased in pregnancy. CRH stimulation testing and inferior petrosal sinus sampling can identify patients with Cushing's disease. Surgery is a safe option for treatment in the second trimester; otherwise medical therapy may be used. Women with known adrenal insufficiency that is appropriately treated can expect to have uneventful pregnancies. Whereas a fetal/placental source of cortisol may mitigate crisis during gestation, unrecognized adrenal insufficiency may lead to maternal or fetal demise either during gestation or in the puerperium. Appropriate treatment and management of labor are reviewed.

/pdf/the-hypothalamic-pituitary-adrenal-axis-in-pregnancy-4xacp189q5.pdf

The Hypothalamic-Pituitary-Adrenal Axis in Pregnancy: Challenges in Disease Detection and Treatment

The acrosome is a unique organelle that plays an important role at the site of sperm–zona pellucida binding during the fertilization process, and is lost in globozoospermia, an inherited infertility syndrome in humans. Although the acrosome is known to be derived from the Golgi apparatus, molecular mechanisms underlying acrosome formation are largely unknown. Here we show that Golgi-associated PDZ- and coiled-coil motif-containing protein (GOPC), a recently identified Golgi-associated protein, is predominantly localized at the trans-Golgi region in round spermatids, and male mice in which GOPC has been disrupted are infertile with globozoospermia. The primary defect was the fragmentation of acrosomes in early round spermatids, and abnormal vesicles that failed to fuse to developing acrosomes were apparent. In later stages, nuclear malformation and an abnormal arrangement of mitochondria, which are also characteristic features of human globozoospermia, were observed. Interestingly, intracytoplasmic sperm injection (ICSI) of such malformed sperm into oocytes resulted in cleavage into blastocysts only when injected oocytes were activated. Thus, GOPC provides important clues to understanding the mechanisms underlying spermatogenesis, and the GOPC-deficient mouse may be a unique and valuable model for human globozoospermia.

https://www.pnas.org/content/pnas/99/17/11211.full.pdf

Lack of acrosome formation in mice lacking a Golgi protein, GOPC.

Intracytoplasmic sperm injection (ICSI) has wide clinical application. In order to achieve good results with this method, it is important to restrict the possibility of oocyte injury as much as possible, and securely inject spermatozoa into the ooplasm. For this purpose, we clinically applied piezo-ICSI, which employs a micromanipulator with piezoelectric elements, to humans, and compared the results with those obtained by conventional ICSI. Conventional ICSI and piezo-ICSI were used in 279 cycles and 335 cycles respectively. Piezo-ICSI showed significantly more favourable results, with a survival rate of 88.1% (conventional ICSI: 81.4, P < 0.001), a fertilization rate of 79.4% (conventional ICSI: 66.4%, P < 0.001), and a pregnancy rate of 23.1% (conventional ICSI: 14.9%, P < 0.05). In piezo-ICSI, the needle used is not sharpened and has a flat tip. However, deformation of the oocyte during insertion of the needle is restrained by vibration of the piezo, and the oolemma is punctured readily and securely by the piezo pulse, at the site where the spermatozoon is injected. Piezo-ICSI is a promising new technique for human ICSI that should improve the survival, fertilization and pregnancy rates after ICSI.

/pdf/the-usefulness-of-a-piezo-micromanipulator-in-8jnklve6ac.pdf

The usefulness of a piezo-micromanipulator in intracytoplasmic sperm injection in humans

In a total of 1048 intracytoplasmic sperm injection (ICSI) cycles, motile spermatozoa from four out of 424 patients (0.9%) failed to fertilize oocytes, despite an apparently successful ICSI procedure. No activation was observed in these injected oocytes. The spermatozoa from three of the four patients were injected into unfertilized mouse oocytes by ICSI (mouse test) to evaluate their oocyte activating ability. The oocyte activation rate of the spermatozoa of patients A, B, and C in the mouse test was 46, 100, and 86% respectively (control: 100%). Simultaneous injection of two spermatozoa from patient A into the mouse oocytes increased the oocyte activating rate to 89% (sham control: 29%). 100% fertilization rates were obtained for patients A and B by combining ICSI and electrical stimulation, and this resulted in pregnancy and the birth of healthy twins for the partner of patient A. Thus, it is considered that the spermatozoa of these patients are not lacking sperm factors but that the activity of these factors is depressed. The combination of ICSI and electrical stimulation is effective in these cases.

Successful fertilization and pregnancy following ICSI and electrical oocyte activation.

Fertilization failure (complete fertilization failure or low fertilization rates) after intracytoplasmic sperm injection (ICSI) can occur in rare cases. In the majority of these cases, the unfertilized oocytes are inactivated. Assisted oocyte activation was applied as a treatment option for a case of low fertilization rate as a clinical trial. A patient with a low fertilization rate (ranging from 0% to 33.3%; mean = 17.0%) after eight previous ICSI cycles at another hospital, was diagnosed with fertilization failure. The most likely cause of fertilization failure was failure of oocyte activation. Therefore, artificial oocyte activation by strontium treatment was combined with ICSI to achieve viable fertilized oocytes. Oocytes were stimulated with strontium (10 mM SrCl(2), 60 min) approximately 30 min after ICSl. Six injected oocytes were stimulated and all were then successfully fertilized. Two blastocysts were transferred into the uterus, resulting in a pregnancy and birth. A second pregnancy was achieved following implantation of two cryopreserved embryos (one blastocyst and one morula). In conclusion, strontium treatment was found to be an effective method for artificial oocyte activation in a case with a low fertilization rate after ICSI.

https://www.rbmojournal.com/article/S1472-6483(10)61027-9/pdf

Successful pregnancy after ICSI with strontium oocyte activation in low rates of fertilization.

The cholesterol/phospholipid (C/PL) ratio was determined for spermatozoa from eight men with normal semen parameters. There was a close correlation between the C/PL ratio and the rate of sperm capacitation as assessed by the hamster egg penetration test. A lower C/PL ratio correlated with a faster capacitation time. This supports the notion that the loss or reduction of membrane cholesterol constitutes an important step of capacitation in human spermatozoa.

Kaoru Yanagida

Papers

Lack of acrosome formation in mice lacking a Golgi protein, GOPC.

The usefulness of a piezo-micromanipulator in intracytoplasmic sperm injection in humans

Successful fertilization and pregnancy following ICSI and electrical oocyte activation.

Successful pregnancy after ICSI with strontium oocyte activation in low rates of fertilization.

Variation in the cholesterol/phospholipid ratio in human spermatozoa and its relationship with capacitation