A series of 10 young sterile men with acephalic spermatozoa or abnormal head-mid-piece attachments is presented. Nine of these patients had 75-100% spermatozoa with minute cephalic ends and 0-25% abnormal head-middle piece attachments. Loose heads ranged between 0-35 for each 100 spermatozoa and normal forms were rare. Two patients were brothers. On ultrastructural examination, the head was generally absent and the middle piece was covered by the plasma membrane. When present, heads implanted at abnormal angles on the middle piece. A testicular biopsy showed abnormal spermiogenesis. The implantation fossa was absent and the flagellar anlage developed independently from the nucleus, resulting in abnormal head-middle piece connections. In one patient azoospermia was induced with testosterone to attempt to increase the normal sperm clone during the rebound phenomenon, but all newly formed spermatozoa were acephalic. In another patient with high numbers of defective head-mid-piece connections, microinjections of spermatozoa resulted in four fertilized oocytes, but syngamy and cleavage did not take place, suggesting an abnormal function of the centrioles. The findings indicate that acephalic spermatozoa arise in the testis as the result of an abnormal neck development during spermiogenesis. The familial incidence and the typical phenotype strongly suggest a genetic origin of the syndrome.

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Prophylactic use of cabergoline has been associated with a decrease in the severity of ovarian hyperstimulation syndrome (OHSS). A prospective randomized study was designed to evaluate the potential of cabergoline to decrease the incidence of OHSS in high-risk patients undergoing assisted reproductive technology treatment; 166 patients with oestradiol concentrations over 4000 pg/ml on the day of human chorionic gonadotrophin (HCG) administration were evaluated. They all received 20 g routine preventive intravenous human albumin on the day of oocyte retrieval. They were then randomized into two groups: group A (n = 83) received 0.5 mg oral cabergoline per day for 3 weeks beginning on the day after oocyte retrieval, and group B (n = 83) received no medication. 'Early' OHSS was defined as being when the onset of the syndrome was initiated during the first 9 days after HCG administration, and 'late' OHSS was defined as being when the onset of the syndrome was initiated from 10 days after HCG administration. In group A, no patients progressed to 'early' OHSS and nine patients (10.8%) developed 'late' OHSS; in group B, 12 patients (15.0%) progressed to 'early' OHSS and three (3.8%) to 'late' OHSS. Although the risk of 'early' OHSS decreased significantly (P < 0.001), the risk of 'late' onset OHSS did not. The two groups presented no changes in pregnancy, implantation or miscarriages rates.

An ultrastructural study of spermatozoa in a series of 247 severely asthenozoospermic patients disclosed two kinds of anomalies. The first was dysplasia of the fibrous sheath, a primary defect of spermatozoa with hypertrophy and hyperplasia of the fibrous sheath, associated axonemal anomalies, familial incidence and chronic respiratory disease. The patients could be divided into two subgroups: the complete form (all spermatozoa affected) and the incomplete form (alterations in 70-80% spermatozoa). There were no spontaneous or in-vitro fertilization (IVF) pregnancies. Intracytoplasmic sperm injection (ICSI) in six patients resulted in successful fertilizations, but only two pregnancies were obtained. These features configure a phenotype that suggests a genetic origin. The second anomaly was non-specific flagellar anomaly (NSFA), random secondary flagellar alterations affecting variable numbers of spermatozoa, without respiratory disease or familial incidence. 54 men with NSFA were followed for 2-6 years. Of these, 18 achieved conception, either spontaneous or by means of assisted fertilization, followed by 14 pregnancies and 12 live births. Their sperm motility significantly increased during the follow-up period. In the remaining 36 men motility did not change during the follow-up period and there were no fertilizations or pregnancies. We conclude that in severe asthenozoospermia, ultrastructural examination of spermatozoa has an effective prognostic value, identifying two syndromes with very different flagellar alterations and fertility potentials.

Mammalian sperm acquire the ability to fertilize eggs by undergoing a process known as capacitation. Capacitation is triggered as the sperm travels through the female reproductive tract. This process involves specific physiological changes such as rearrangement of the cell plasma membrane, post-translational modifications of certain proteins, and changes in the cellular permeability to ions-with the subsequent impact on the plasma membrane potential (Em). Capacitation-associated Em hyperpolarization has been well studied in mouse sperm, and shown to be both necessary and sufficient to promote the acrosome reaction (AR) and fertilize the egg. However, the relevance of the sperm Em upon capacitation on human fertility has not been thoroughly characterized. Here, we performed an extensive study of the Em change during capacitation in human sperm samples using a potentiometric dye in a fluorimetric assay. Normospermic donors showed significant Em hyperpolarization after capacitation. Em values from capacitated samples correlated significantly with the sperm ability to undergo induced AR, highlighting the role of hyperpolarization in acrosomal responsiveness, and with successful in vitro fertilization (IVF) rates. These results show that Em hyperpolarization could be an indicator of human sperm fertilizing capacity, setting the basis for the use of Em values as a robust predictor of the success rate of IVF.