Aim: To evaluate the effect of chronic hypoxia on human spermatogenic parameters and their recovery time.
Methods: Seminological parameters of six male healthy mountain trekkers were evaluated in normoxia at sea level. After 26 days exposure to altitude (ranging from 2 000 m to 5 600 m, Karakorum Expedition) the same parameters were again evaluated after returning to sea level. These parameters were once again evaluated after 1 month and then again after 6 months.
Results: Sperm count was found to be lower immediately after returning to sea level (P = 0.0004) and again after a month (P = 0.0008). Normal levels were reached after 6 months. Spermatic motility (%) shows no reduction immediately after returning to sea level (P = 0.0583), whereas after 1 month this reduction was significant (P = 0.0066). After 6 months there was a recovery to pre-hypoxic exposure values. Abnormal or immature spermatozoa (%) increased immediately after returning to sea level (P = 0.0067) and then again after 1 month (P = 0.0004). After 6 months there was a complete recovery to initial values. The total number of motile sperm in the ejaculate was found to be lower immediately after returning to sea level (P = 0.0024) and then again after 1 month (P = 0.0021). After 6 months there was a recovery to pre-hypoxic exposure values.
Conclusion: Chronic hypoxia induces a state of oligospermia and the normalization of such seminological parameters at the restoration of previous normoxic conditions after 6 months indicate the influence of oxygen supply in physiological mechanisms of spermatogenesis and male fertility.
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http://dx.doi.org/10.1111/j.1745-7262.2008.00346.x | DOI Listing |
Proc Natl Acad Sci U S A
February 2025
Department of Earth System Sciences, Center for Earth System Research and Sustainability, University of Hamburg, Hamburg 20146, Germany.
As an essential micronutrient, phosphorus plays a key role in oceanic biogeochemistry, with its cycling intimately connected to the global carbon cycle and climate change. Authigenic carbonate fluorapatite (CFA) has been suggested to represent a significant phosphorus sink in the deep ocean, but its formation mechanisms in oceanic low-productivity settings remain poorly constrained. Applying X-ray absorption near edge structure, transmission electron microscopy, and laser ablation inductively coupled plasma mass spectrometer analyses, we report a unique mineral assemblage where CFA crystals coat phillipsite in abyssal sediments of the East Mariana Basin and the Philippine Sea.
View Article and Find Full Text PDFEnviron Monit Assess
January 2025
ICAR-Central Institute of Fisheries Education, Mumbai, 400061, India.
Phytoplankton are diverse photosynthetic organisms in estuarine ecosystems and sensitive indicators of environmental changes. This study employed Generalized Additive Model (GAM) to explore the impact of environmental variables on the abundance of six dominant phytoplankton species in the tropical Karanja estuary, India. Data were collected from five sampling stations between January 2022 and March 2023.
View Article and Find Full Text PDFInt Marit Health
January 2025
Institute for Occupational and Maritime Medicine (ZfAM), University Medical Center Hamburg-Eppendorf (UKE), Seewartenstraße 10, 20459 Hamburg, Hamburg, Germany.
Background: Seafarers are exposed to a variety of job-specific physical and psychosocial stressors. Health promotion on board is of great importance for the salutogenesis of this occupational group. Due to the difficult accessibility of seafarers, electronically supported health management can be highly valuable.
View Article and Find Full Text PDFJ Int Soc Prev Community Dent
December 2024
Scientific Research Department, Research Group in Dental Sciences, School of Dentistry, Universidad Científica del Sur, Lima, Perú.
Aim: This study aimed to identify factors associated with adolescents' knowledge, practices, and attitudes (KPA-OH) regarding oral health in the Rupa-Rupa district, a high jungle region of Peru.
Materials And Methods: An analytical study was conducted with a sample of 408 adolescents (aged 13-17 years) from seven public schools in the Rupa-Rupa district (elevation: 649 meters above sea level). The sample was stratified by sex, age, and school.
Oxygen (Basel)
March 2025
Centro de Investigación en Medicina de Altura (CIMA), Facultad de Medicina Humana, Universidad de San Martín de Porres, Lima 15001, Peru.
Previous studies indicate that individuals at high altitudes have a lower pain threshold than those living at sea level. This study evaluates the differences in pain perception among young people living at an altitude of 3800 m and after acute exposure to a severe hypoxic environment at more than 5100 m. Fourteen people (BMI of 22.
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