Analysis of the factors influencing male infertility of reproductive age in Jinan.

OBJECTIVE: The World Health Organization (WHO) defines infertility as a person failing to achieve a pregnancy after 12 months or more of regular unprotected sexual intercourse. Infertility includes female infertility and male infertility. The aim of this paper is to study the etiology of infertility and related influencing factors in men of reproductive age in Jinan. PATIENTS AND METHODS: In this study, 172 male infertile patients who attended the Department of Assisted Reproduction of Shandong Provincial Maternal and Child Health Hospital in Shandong, China and the Infertility Clinic of Jinan Central Hospital in Shandong, China from August 2021 to April 2022 are selected as the study population (infertility group). A convenience sampling method is used to select 257 men from couples attending the Obstetrics Department of Qilu Hospital in Shandong, China, the Obstetrics Department of the Second Hospital of Shandong University in Shandong, China, and the Obstetrics Department of Maternal and Child Health Hospital in Shandong, China from October 2021 to February 2022 as the study subjects (control group). A self-designed questionnaire is used to conduct the survey, which includes basic personal information, lifestyle information, marital and family-related information, and one-way and multi-way logistic regression analyses are performed. RESULTS: The average age of the case group and the control group are 34.03±5.13 years old and 33.61±8.18 years old; the average height is 175.80±5.91 cm and 176.78±5.25 cm; the average weight is 80.28±14.70 kg and 83.09±45.36 kg. The differences in age, height, and weight between the case group and the control group are not statistically significant by t-test. Moderate oligospermia is the predominant cause of infertility in men of reproductive age in Jinan. A multifactorial logistic regression analysis yields that academic qualifications (OR=2.518, 95% CI: 1.023 to 6.196), coffee consumption (OR=7.692, 95% CI: 1.623 to 36.460), living in a room that had been renovated within a period of time (OR=2.769, 95% CI: 1.104 to 6.949), stress level (OR=47.280, 95% CI: 23.656-94.494), quality of sexual life (OR=3.352, 95% CI: 1.331-8.442), and duration of couple separation (OR=3.851, 95% CI: 1.094-13.557) are the main risk factors for infertility in men of reproductive age in Jinan. CONCLUSIONS: In this study, a total of 6 risk factors are screened for male infertility in Jinan in the reproductive age, including high academic qualifications, coffee consumption, living in a room that has finished renovation within 3 months, high stress, poor quality of sexual life, and long spousal separation. Three factors can be controlled, avoided, or reduced through personal actions; the factors are coffee consumption, living in a room that has finished renovation within 3 months, and high stress, all of which may reduce the level of male reproductive health.

Extensible collagen in mussel byssus: a natural block copolymer.

To adhere to solid surfaces, marine mussels produce byssal threads, each of which is a stiff tether at one end and a shock absorber with 160 percent extensibility at the other end. The elastic extensibility of proximal byssus is extraordinary given its construction of collagen and the limited extension (less than 10 percent) of most collagenous materials. From the complementary DNA, we deduced that the primary structure of a collagenous protein (preCol-P) predominating in the extensible proximal portion of the threads encodes an unprecedented natural block copolymer with three major domain types: a central collagen domain, flanking elastic domains, and histidine-rich terminal domains. The elastic domains have sequence motifs that strongly resemble those of elastin and the amorphous glycine-rich regions of spider silk fibroins. Byssal thread extensibility may be imparted by the elastic domains of preCol-P.