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Category: sex

If you need an excuse to turn off the laptop over the weekend or rein in overtime, scientists have found that working extended hours actually changes parts of the brain linked to emotional regulation, working memory and solving problems. While we know the toll that “overwork” takes physically and mentally, the precise neurological impact has not been well understood.

An international team of researchers including scientists from Korea’s Chung-Ang University assessed 110 healthcare workers – 32 who worked excessive hours (52 or more per week) and 78 who clocked less than 52 hours per week, or what would be considered closer to standard hours in the field. Voxel based morphometry (VBM) to assess gray matter and atlas-based analysis was then applied to MRI scans of each individual’s brain, identifying volume and connectivity differences.

When the scientists adjusted the results to account for age and sex, they found that, in the overworked cohort, the imaging showed a significant difference in brain volume in 17 different regions of the organ – including the middle frontal gyrus (MFG), insula and superior temporal gyrus (STG). Atlas-based analysis identified that, in the overworked individuals, there was 19% more volume in the left caudal MFG. The MFG – part of the brain’s frontal lobe – is the heavy lifter when it comes to executive functioning like emotional regulation, working memory, attention and planning, while the STG’s main task is auditory and language processing. The insula, meanwhile, is key in pain processing and other sensory signaling.

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Is there a difference in brain structure between men and women? If we were to find such a difference in a single neuron, would it matter?

One of the most useful models for studying these questions is the nematode Caenorhabditis elegans (C. elegans). This tiny worm has several characteristics that make it an excellent research model, one of which is that every cell in its body has a predetermined identity and lineage.

Like humans, C. elegans has two sexes. However, instead of male and female, the two sexes of this worm are male and hermaphrodite—a self-fertilizing individual capable of producing both male and female gametes (sperm and eggs), allowing it to reproduce without a partner.

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While cannabis is known to have immunomodulatory properties, the clinical consequences of its use on outcomes in COVID-19 have not been extensively evaluated. We aimed to assess whether cannabis users hospitalized for COVID-19 had improved outcomes compared to non-users.

We conducted a retrospective analysis of 1831 patients admitted to two medical centers in Southern California with a diagnosis of COVID-19. We evaluated outcomes including NIH COVID-19 Severity Score, need for supplemental oxygen, ICU (intensive care unit) admission, mechanical ventilation, length of hospitalization, and in-hospital death for cannabis users and non-users. Cannabis use was reported in the patient’s social history. Propensity matching was used to account for differences in age, body-mass index, sex, race, tobacco smoking history, and comorbidities known to be risk factors for COVID-19 mortality between cannabis users and non-users.

Of 1831 patients admitted with COVID-19, 69 patients reported active cannabis use (4% of the cohort). Active users were younger (44 years vs. 62 years, p < 0.001), less often diabetic (23.2% vs 37.2%, p < 0.021), and more frequently active tobacco smokers (20.3% vs. 4.1%, p < 0.001) compared to non-users. Notably, active users had lower levels of inflammatory markers upon admission than non-users—CRP (C-reactive protein) (3.7 mg/L vs 7.6 mg/L, p < 0.001), ferritin (282 μg/L vs 622 μg/L, p < 0.001), D-dimer (468 ng/mL vs 1,140 ng/mL, p = 0.017), and procalcitonin (0.10 ng/mL vs 0.15 ng/mL, p = 0.001). Based on univariate analysis, cannabis users had significantly better outcomes compared to non-users as reflected in lower NIH scores (5.1 vs 6.0, p < 0.001), shorter hospitalization (4 days vs 6 days, p < 0.001), lower ICU admission rates (12% vs 31%, p < 0.001), and less need for mechanical ventilation (6% vs 17%, p = 0.027).

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Recent advancements in in-vitro gametogenesis (IVG) suggest that lab-grown eggs and sperm could become viable within the next decade. This technology holds the promise of revolutionizing fertility treatments, particularly for individuals facing infertility and same-sex couples desiring biological children. However, it also raises significant ethical and medical considerations that must be carefully addressed.

The Human Fertilisation and Embryology Authority (HFEA), the UK’s fertility regulator, has reported that the development of lab-grown gametes, known as in-vitro gametogenesis (IVG), may become a practical option within the next decade. This technology involves creating eggs and sperm from reprogrammed skin or stem cells, potentially transforming fertility treatments by removing age-related barriers and enabling same-sex couples to have biological children.

IVG represents a significant advancement in reproductive science. By generating gametes in the laboratory, scientists can overcome challenges associated with traditional fertility treatments. This approach could provide new avenues for individuals with infertility issues and offer same-sex couples the opportunity to have children genetically related to both partners.

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Variation exists in the expression of romantic love, but to date, no studies have specifically investigated this phenomenon. This study employed a TwoStep cluster analysis to group 809 partnered young adults experiencing romantic love from the Romantic Love Survey 2022 according to intensity of romantic love, obsessive thinking, commitment, and frequency of sex per week. The results revealed four clusters: (i) mild romantic lovers (20.02%) characterized by the lowest intensity, lowest obsessive thinking, lowest commitment, and lowest frequency of sex; (ii) moderate romantic lovers (40.91%), characterized by relatively low intensity, relatively low obsessive thinking, relatively high commitment, and relatively moderate frequency of sex; (iii) libidinous romantic lovers (9.64%), characterized by relatively high intensity, relatively high obsessive thinking, relatively high commitment, and exceptionally high frequency of sex; and (iv) intense romantic lovers (29.42%), characterized by the highest intensity, highest obsessive thinking, highest commitment, and relatively high frequency of sex. Each cluster differs on a range of personal and relationship characteristics. The findings can generate theory and hypotheses about romantic love and provide impetus for future research.

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In human society, men tend to be seen as risk-takers, while women are seen as being more cautious. According to evolutionary psychologists, this difference developed in the wake of threats to each sex and their respective needs. While such generalizations are, of course, too binary and simplistic to faithfully describe complex and multifaceted human behavior, clearcut differences between females and males are often evident in other animals, even in simple organisms such as worms.

In a new study published in Nature Communications, Weizmann Institute of Science researchers showed that male worms are worse at learning from experience and find it hard to avoid taking risks—even at the cost of their own lives—and that allowing them to mate with members of the opposite sex improves these capabilities.

The scientists also discovered a protein, evolutionarily conserved in creatures from worms all the way to humans, that appears to be responsible for the different learning abilities of the two sexes.

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As an initial step, we selected ARDs associated with hallmarks of aging. These included a total of 83 diseases linked to one or more hallmarks of aging, based on the taxonomy put forward in ref. 4 (Supplementary Table 2). Support for this taxonomy comes from multiple sources. Analyses of electronic health records from general practice and hospitalizations identified more than 200 diseases with incidence rates increasing with chronological age6,22. Researchers linked a subset of these ARDs to specific hallmarks of aging using several approaches: mining 1.85 million PubMed abstracts on human aging, identifying shared genes in the genome-wide association study catalog, conducting gene set enrichment analysis and analyzing disease co-occurrence networks within each hallmark4.

We confirmed the co-occurrence of ARDs within each hallmark in 492,257 participants from the UK Biobank study23. The presence of one ARD increased the risk of developing another ARD related to the same hallmark, with clustering coefficients ranging from 0.76 for LOP-specific ARDs to 0.92 for SCE-specific ARDs. These findings corroborated the hallmark-specific clustering of ARDs (Extended Data Figs. 3 and 4)23.

In time-to-event analyses of UK Biobank and FPS participants without these ARDs at baseline (n ranging from 477,325 to 492,294 in the UK Biobank and from 278,272 to 286,471 in the FPS, depending on the social disadvantage indicator and ARD), social disadvantage—indicated by education and adult SES (neighborhood deprivation)—was associated with a higher risk of developing ARDs. In the UK Biobank, the age-, sex-and ethnicity-adjusted hazard ratio for developing any ARD was 1.31 (95% confidence interval (CI) 1.29–1.33) for individuals with low compared with high education. For individuals with high versus low adult SES, the hazard ratio was 1.21 (95% CI 1.20–1.23). In the FPS, the corresponding hazard ratios were 1.28 (95% CI 1.25–1.31) and 1.23 (95% CI 1.20–1.27), respectively.

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Summary: A new study reveals how prenatal infections followed by early-life stress—known as “two-hit stress”—can lead to brain dysfunction and psychiatric-like behaviors. Researchers found that affected mice showed abnormal cerebellar activity, increased microglial turnover, and impaired brain-wide connectivity.

Notably, microglia replacement therapy successfully reversed these effects, offering a potential new approach for mental health treatments. The findings suggest that sex differences may influence stress resilience, highlighting the need for personalized treatments for psychiatric and neurodegenerative disorders.

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While most animals reproduce sexually, some species rely solely on females for parthenogenetic reproduction. Even in these species, rare males occasionally appear. Whether these males retain reproductive functions is a key question in understanding the evolution of reproductive strategies.

A new study published in Ecology by a research team led by Assistant Professor Tomonari Nozaki from the National Institute for Basic Biology, Professor Kenji Suetsugu from Kobe University, and Associate Professor Shingo Kaneko from Fukushima University provides insight into this question. The researchers focused on the rare males of Ramulus mikado, a stick insect species in Japan, where parthenogenesis is predominant. Their analysis of male reproductive behavior reveals new findings.

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