Sex hormones differently regulate lipid metabolism genes in primary human hepatocytes.

BACKGROUND: Prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) is higher in men than in women. Hormonal and genetic causes may account for the sex differences in MASLD. Current human in vitro liver models do not sufficiently take the influence of biological sex and sex hormones into consideration. METHODS: Primary human hepatocytes (PHHs) were isolated from liver specimen of female and male donors and cultured with sex hormones (17ß-estradiol, testosterone and progesterone) for up to 72 h. mRNA expression levels of 8 hepatic lipid metabolism genes were analyzed by RT-qPCR. Sex hormones and their metabolites were determined in cell culture supernatants by LC-MS analyses. RESULTS: A sex-specific expression was observed for LDLR (low density lipoprotein receptor) with higher mRNA levels in male than female PHHs. All three sex hormones were metabolized by PHHs and the effects of hormones on gene expression levels varied depending on hepatocyte sex. Only in female PHHs, 17ß-estradiol treatment affected expression levels of PPARA (peroxisome proliferator-activated receptor alpha), LIPC (hepatic lipase) and APOL2 (apolipoprotein L2). Further changes in mRNA levels of female PHHs were observed for ABCA1 (ATP-binding cassette, sub-family A, member 1) after testosterone and for ABCA1, APOA5 (apolipoprotein A-V) and PPARA after progesterone treatment. Only the male PHHs showed changing mRNA levels for LDLR after 17ß-estradiol and for APOA5 after testosterone treatment. CONCLUSIONS: Male and female PHHs showed differences in their expression levels of hepatic lipid metabolism genes and their responsiveness towards sex hormones. Thus, cellular sex should be considered, especially when investigating the pathophysiological mechanisms of MASLD.

Sex Differences in Alcohol Use: Is It All About Hormones?

Risky alcohol use and alcohol use disorders (AUD) are a rising problem in women, yet a major disparity in our understanding of what drives alcohol consumption in women remains. Historically biomedical research has focused on male subjects; however, recent increases in reporting of females, have highlighted major differences between the sexes. Here we review the current literature of the effect of gonadal steroid hormones (estrogens, androgens, and progestins), neurosteriods, and neurobiological factors on alcohol use in clinical and preclinical studies of both sexes. Further, we briefly discuss how fundamental sex differences in genetics, metabolism, neuroimmune, and stress responses may influence sex differences in alcohol intake. Comparing the sexes could aid in the discovery of novel therapeutics to treat AUD, and implementation of current treatment options in women.

Sex- and Gender-Related Differences in Obesity: From Pathophysiological Mechanisms to Clinical Implications.

Obesity, primarily characterized by excessive fat accumulation, is a multifactorial chronic disease with an increasing global prevalence. Despite the well-documented epidemiology and significant advances in understanding its pathophysiology and clinical implications, the impact of sex is typically overlooked in obesity research. Worldwide, women have a higher likelihood to become obese compared to men. Although women are offered weight loss interventions more often and at earlier stages than men, they are more vulnerable to psychopathology. Men, on the other hand, are less likely to pursue weight loss intervention and are more susceptible to the metabolic implications of obesity. In this narrative review, we comprehensively explored sex- and gender-specific differences in the development of obesity, focusing on a variety of biological variables, such as body composition, fat distribution and energy partitioning, the impact of sex steroid hormones and gut microbiota diversity, chromosomal and genetic variables, and behavioural and sociocultural variables influencing obesity development in men and women. Sex differences in obesity-related comorbidities and varying effectiveness of different weight loss interventions are also extensively discussed.

Sex hormone deprivation abolishes sex-specific differences in murine colon inflammation and related lipid mediator production.

Unresolved inflammation, due to unfavorable imbalances between pro-inflammatory and pro-resolving mediators, leads to chronic inflammatory pathologies that are often sex-biased and regulated by sex hormones, including inflammatory bowel disease. Lipid mediators (LM) produced from polyunsaturated fatty acids by various lipoxygenases (LOX) and cyclooxygenases govern all stages of inflammation, i.e., the initiation and progression by pro-inflammatory eicosanoids and its resolution by specialized pro-resolving mediators (SPM). Here, we reveal sex-specific differences in murine experimental colitis with male preponderance, which was abolished by sex hormone deprivation using gonadectomy, and this correlated to the levels of inflammation-relevant mediators in the colon. Oral dextran sodium sulfate administration caused more severe colon inflammation in male CD-1 mice than in female counterparts during the acute phase. Colitis in males yielded higher colonic cytokine/chemokine levels but lower 12-/15-LOX-derived LM including SPM compared to female animals in the resolving phase. Sex hormone deprivation in male mice by orchidectomy ameliorated colitis and impaired pro-inflammatory cytokine/chemokine levels but elevated 12-/15-LOX products including SPM, thus abolishing the observed sex differences. Conversely, ovariectomy impaired the levels of those LM that dominated in females and that were increased in males after gonadectomy. Our findings suggest that male sex hormones promote the development of colitis connected to the biosynthesis of inflammatory cytokines, chemokines, and certain LM, especially pro-resolving 12-/15-LOX products that appear to be suppressed in the male colon due to androgens.

Assessment of environmental exposure to betamethasone on the reproductive function of female Japanese medaka (Oryzias latipes).

Betamethasone has been extensively used in medicine in recent years and poses potential hazards to aquatic organisms. This study investigated the reproductive toxic effects of betamethasone exposure in fish, employing female Japanese medaka (Oryzias latipes) as a model. Betamethasone exposure at environmentally relevant concentrations (0, 20, 200, and 2000 ng/L) for a period of 15 weeks resulted in its high accumulation in the ovary, leading to abnormal oogenesis in female Japanese medaka. The production of gonadotropins (LH and FSH) in the pituitary gland was inhibited, and sex steroid biosynthesis in the ovary was significantly influenced at the transcriptional level. The imbalance of androgens and estrogens resulted in a decrease in the E2/T ratio and hepatic VTG synthesis, and the suppression of estrogen receptor signaling was also induced. Furthermore, betamethasone exposure delayed spawning and reduced fertility in the F0 generation, and had detrimental effects on the fertilization rate and hatchability of the F1 generation. Our results showed that environmental betamethasone had the potential to adversely affect female fertility and steroid hormone dynamics in fish.

Epigenetic developmental mechanisms underlying sex differences in cancer.

Cancer risk is modulated by hereditary and somatic mutations, exposures, age, sex, and gender. The mechanisms by which sex and gender work alone and in combination with other cancer risk factors remain underexplored. In general, cancers that occur in both the male and female sexes occur more commonly in XY compared with XX individuals, regardless of genetic ancestry, geographic location, and age. Moreover, XY individuals are less frequently cured of their cancers, highlighting the need for a greater understanding of sex and gender effects in oncology. This will be necessary for optimal laboratory and clinical cancer investigations. To that end, we review the epigenetics of sexual differentiation and its effect on cancer hallmark pathways throughout life. Specifically, we will touch on how sex differences in metabolism, immunity, pluripotency, and tumor suppressor functions are patterned through the epigenetic effects of imprinting, sex chromosome complement, X inactivation, genes escaping X inactivation, sex hormones, and life history.

Hearts apart: sex differences in cardiac remodeling in health and disease.

Biological sex is an important modifier of physiology and influences pathobiology in many diseases. While heart disease is the number one cause of death worldwide in both men and women, sex differences exist at the organ and cellular scales, affecting clinical presentation, diagnosis, and treatment. In this Review, we highlight baseline sex differences in cardiac structure, function, and cellular signaling and discuss the contribution of sex hormones and chromosomes to these characteristics. The heart is a remarkably plastic organ and rapidly responds to physiological and pathological cues by modifying form and function. The nature and extent of cardiac remodeling in response to these stimuli are often dependent on biological sex. We discuss organ- and molecular-level sex differences in adaptive physiological remodeling and pathological cardiac remodeling from pressure and volume overload, ischemia, and genetic heart disease. Finally, we offer a perspective on key future directions for research into cardiac sex differences.

Outcomes of dietary alpha-lipoic acid on testicular vascularization, steroid hormones, and seminal quality in aged Baladi bucks.

BACKGROUND: Senescence is accompanied by a progressive decrease in male reproductive performance, mainly due to oxidative stress and endothelial dysfunction. Alpha lipoic acid (ALA) is a potent antioxidant, that diffuses freely in aqueous and lipid phases, possessing anti-inflammatory and anti-apoptotic properties. This study aimed to examine the effects of supplemental dietary ALA on testicular hemodynamics (TH), circulating hormones, and semen quality in aged goats. Twelve Baladi bucks were divided into two groups (n = 6 each); the first fed a basic ration and served as a control group (CON), while the second received the basic ration supplemented with 600 mg ALA/ kg daily for consecutive eight weeks (ALA). RESULTS: There were improvements in testicular blood flow in the ALA group evidenced by a lower resistance index (RI) and pulsatility index (PI) concurrent with higher pampiniform-colored areas/pixel (W3-W6). There were increases in testicular volume and decreases in echogenicity (W3-W5; ALA vs. CON). Compared to the CON, ALA-bucks had higher serum concentrations of testosterone, estradiol, and nitric oxide (W3-W5). There were enhancements in semen traits (progressive motility, viability, morphology, and concentration, alanine aminotransferase enzyme) and oxidative biomarkers (catalase, total antioxidant capacity, and malondialdehyde). CONCLUSIONS: ALA dietary supplementation (600 mg/kg diet) improved aged bucks' reproductive performance by enhancing the testicular volume, testicular hemodynamics, sex steroids, and semen quality.

Hormonal regulation in diabetes: Special emphasis on sex hormones and metabolic traits.

Diabetes constitutes a significant global public health challenge that is rapidly reaching epidemic proportions. Among the non-communicable diseases, the incidence of diabetes is rising at an alarming rate. The International Diabetes Federation has documented a 9.09% prevalence of diabetes among individuals aged between 20 and 79 years. The interplay of gonadal hormones and gender differences is critical in regulating insulin sensitivity and glucose tolerance, and this dynamic is particularly crucial because of the escalating incidence of diabetes. Variations in insulin sensitivity are observed across genders, levels of adiposity, and age groups. Both estrogen and testosterone are seen to influence glucose metabolism and insulin sensitivity. This chapter surveys the present knowledge of sex differences, sex hormones, and chromosomes on insulin imbalance and diabetes development. It further highlights the influence of metabolic traits in diabetes and changes in sex hormones during diabetic pregnancy. Notably, even stressful lifestyles have been acknowledged to induce hormonal imbalances. Furthermore, it discusses the potential of hormonal therapy to help stabilize sex hormones in diabetic individuals and focuses on the most recent research investigating the correlation between sex hormones and diabetes.

Fetal gender prediction by monitoring circulating steroid hormones and some biochemical parameters in maternal dromedary camels.

To predict the sex of the foetus, healthy pregnant dromedary camels (n = 24) were included. Blood samples were collected for measurements of progesterone, estradiol, testosterone, and cortisol as well as total proteins, albumin, glucose, creatinine, blood urea nitrogen, phosphorus, calcium, creatine kinase, alanine aminotransferase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), gamma glutamyl transpeptidase (GGT), calcium, phosphorus, and magnesium. Statistical analysis revealed differences between pregnant camels and pregnant camels in terms of female or male foetuses depending on the actual sex of the born calf. The results revealed that testosterone and ALP concentrations were significantly (P < 0.001) greater in camels given to males than in those given to calves. There were strong positive correlations between male calf birth and testosterone and ALP concentrations (r = 0.864; P < 0.0001 and r = 0.637; P < 0.001, respectively). On the other hand, the cortisol, glucose and creatinine concentrations were significantly lower (P lower in camel calved males than in females). There were significant negative correlations between male calf birth and the cortisol, glucose and creatinine concentrations (r =-0.401; P = 0.052; r =-0.445; P = 0.029 and r =-0.400; P = 0.053, respectively). The concentrations of calcium, phosphorus, calcium/phosphorus ratio, magnesium, and albumin and the albumin/globulin ratio were not significantly different (P > 0.05) between the two groups. In conclusion, testosterone could be used as a biomarker to determine the sex of foetuses in dromedary camels.

Levels of Sex Hormones and Abdominal Muscle Composition in Men from The Multi-Ethnic Study of Atherosclerosis.

Information on the associations of testosterone levels with abdominal muscle volume and density in men is limited, while the role of estradiol and SHBG on these muscle characteristics are unclear. Therefore, this study aimed to investigate the association between fasting serum sex hormones and CT-derived abdominal muscle area and radiodensity in adult men. Conducted as a cross sectional observational study using data from the Multi-Ethnic Study of Atherosclerosis, our analyses focused on a community-based sample of 907 men aged 45-84 years, with 878 men having complete data. CT scans of the abdomen were interrogated for muscle characteristics, and multivariable linear regressions were used to test the associations. After adjustment for relevant factors, higher levels of both total testosterone and estradiol were associated with higher abdominal muscle area (1.74, 0.1-3.4, and 1.84, 0.4-3.3, respectively). In the final analyses, levels of total testosterone showed a positive association, while an inverse relationship was observed for SHBG with abdominal muscle radiodensity (0.3, 0.0-0.6, and - 0.33, - 0.6 to - 0.1, respectively). Our results indicate a complex association between sex hormones and abdominal muscle characteristics in men. Specifically, total testosterone and estradiol were associated with abdominal muscle area, while only total testosterone was associated with muscle radiodensity and SHBG was inversely associated with muscle radiodensity.Clinical Trial: NCT00005487.

Circulating adrenal and gonadal steroid hormones heterogeneity in active young males and the contribution of 11-oxy androgens.

The classical androgens, testosterone and dihydrotestosterone, together with dehydroepiandrosterone, the precusrsor to all androgens, are generally included in diagnostic steroid evaluations of androgen excess and deficiency disorders and monitored in androgen replacement and androgen suppressive therapies. The C11-oxy androgens also contribute to androgen excess disorders and are still often excluded from clinical and research-based steroids analysis. The contribution of the C11-oxy androgens to the androgen pool has not been considered in androgen deficiency. An exploratory investigation into circulating adrenal and gonadal steroid hormones in men was undertaken as neither the classical androgens nor the C11-oxy androgens have been evaluated in the context of concurrent measurement of all adrenal steroid hormones. Serum androgens, mineralocorticoids, glucocorticoids, progesterones and androgens were assessed in 70 healthy young men using ultra high performance supercritical fluid chromatography and tandem mass spectrometry. Testosterone, 24.5 nmol/L was the most prominent androgen detected in all participants while dihydrotestosterone, 1.23 nmol/L, was only detected in 25% of the participants. The 11-oxy androgens were present in most of the participants with 11-hydroxyandrostenedione, 3.37 nmol, in 98.5%, 11-ketoandrostenedione 0.764 in 77%, 11-hydroxytestosterone, 0.567 in 96% and 11-ketotestosterone: 0.440 in 63%. A third of the participants with normal testosterone and comparable 11-ketotestosterone, had significantly lower dehydroepiandrosterone (p < 0.001). In these males 11-hydroxyandrostenedione (p < 0.001), 11-ketoandrostenedione (p < 0.01) and 11-hydroxytestosterone (p < 0.006) were decreased. Glucocorticoids were also lower: cortisol (p < 0.001), corticosterone (p < 0.001), cortisone (p < 0.006) 11-dehydrocorticosterone (p < 0.001) as well as cortisol:cortisone (p < 0.001). The presence of dehydroepiandrosterone was associated with 16-hydroxyprogesterone (p < 0.001), which was also significantly lower. Adrenal and gonadal steroid analysis showed unexpected steroid heterogeneity in normal young men. Testosterone constitutes 78% of the circulating free androgens with the 11-oxy androgens abundantly present in all participants significantly contributing 22%. In addition, a subset of men were identified with low circulating dehydroepiandrosterone who showed altered adrenal steroids with decreased glucocorticoids and decreased C11-oxy androgens. Analysis of the classical and 11-oxy androgens with the additional measurement of dehydroepiandrosterone and 16-hydroxyprogesterone may allow better diagnostic accuracy in androgen excess or deficiency.

Impact of transsexualizing process centers on self-medication of transgender individuals.

OBJECTIVE: The transgender population in Brazil faces marginalization and difficulties in accessing education and health, leading many individuals to self-medicate. This study aimed to evaluate the impact of the implementation of Specialized Centers in the Transsexualizing Process (SCTP) on the use of cross-sex hormone therapy (CSHT) without medical prescription, as well as the level of education and mental health profile of these individuals. METHODS: This is a cross-sectional study with data from physical and electronic medical records between September 2017 and February 2023 regarding the use of CSHT before and after the implementation of two SCTP in the state of Bahia, Brazil, in addition to data on education level, previous diagnosis of anxiety and depression of patients. RESULTS: A total of 219 participants, 127 transgender men (TM) and 92 transgender women and travestis (TrTW), were assessed. A significant reduction in the prevalence of self-medication was observed in both TrTW (92.98% before and 51.43% after, p<0.001), and TM (47.17% before and 25.67% after, p = 0.010) with the implementation of SCTP. Transgender individuals who used CSHT before accessing the service were found to have a lower prevalence of depression. Self-medication was not significantly associated with education or anxiety in our sample. CONCLUSION: The results indicate the need for the expansion of SCTP, as they were associated with lower rates of self-medication in the transgender population.

Sex-Based Mechanisms of Cardiac Development and Function: Applications for Induced-Pluripotent Stem Cell Derived-Cardiomyocytes.

Males and females exhibit intrinsic differences in the structure and function of the heart, while the prevalence and severity of cardiovascular disease vary in the two sexes. However, the mechanisms of this sex-based dimorphism are yet to be elucidated. Sex chromosomes and sex hormones are the main contributors to sex-based differences in cardiac physiology and pathophysiology. In recent years, the advances in induced pluripotent stem cell-derived cardiac models and multi-omic approaches have enabled a more comprehensive understanding of the sex-specific differences in the human heart. Here, we provide an overview of the roles of these two factors throughout cardiac development and explore the sex hormone signaling pathways involved. We will also discuss how the employment of stem cell-based cardiac models and single-cell RNA sequencing help us further investigate sex differences in healthy and diseased hearts.

Sex differences in acute early life stress-enhanced fear learning in adult rats.

Patients diagnosed with posttraumatic stress disorder (PTSD) present with a spectrum of debilitating anxiety symptoms resulting from exposure to trauma. Women are twice as likely to be diagnosed with anxiety and PTSD compared to men; however, the reason for this vulnerability remains unknown. We conducted four experiments where we first demonstrated a female vulnerability to stress-enhanced fear learning (SEFL) with a moderate, acute early life stress (aELS) exposure (4 footshocks in a single session), compared to a more intense aELS exposure (15 footshocks in a single session) where males and females demonstrated comparable SEFL. Next, we demonstrated that this female vulnerability does not result from differences in footshock reactivity or contextual fear conditioning during the aELS exposure. Finally, using gonadectomy or sham surgeries in adult male and female rats, we showed that circulating levels of gonadal steroid hormones at the time of adult fear conditioning do not explain the female vulnerability to SEFL. Additional research is needed to determine whether this vulnerability can be explained by organizational effects of gonadal steroid hormones or differences in sex chromosome gene expression. Doing so is critical for a better understanding of increased female vulnerability to certain psychiatric diseases.

Gender and sex hormone effects on neonatal innate immune function.

OBJECTIVES: Scientific evidence provides a widened view of differences in immune response between male and female neonates. The X-chromosome codes for several genes important in the innate immune response and neonatal innate immune cells express receptors for, and are inhibited by, maternal sex hormones. We hypothesized that sex differences in innate immune responses may be present in the neonatal population which may contribute to the increased susceptibility of premature males to sepsis. We aimed to examine the in vitro effect of pro-inflammatory stimuli and hormones in neutrophils and monocytes of male and female neonates, to examine the expression of X-linked genes involved in innate immunity and the miRNA profiles in these populations. METHODS: Preterm infants (n = 21) and term control (n = 19) infants were recruited from the Coombe Women and Infants University Hospital Dublin with ethical approval and explicit consent. The preterm neonates (eight female, 13 male) were recruited with a mean gestation at birth (mean ± SD) of 28 ± 2 weeks and corrected gestation at the time of sampling was 30 + 2.6 weeks. The mean birth weight of preterm neonates was 1084 ± 246 g. Peripheral blood samples were used to analyze immune cell phenotypes, miRNA human panel, and RNA profiles for inflammasome and inflammatory genes. RESULTS: Dividing neutrophil results by sex showed no differences in baseline CD11b between sexes among either term or preterm neonates. Examining monocyte CD11b by sex shows, that at baseline, total and classical monocytes have higher CD11b in preterm females than preterm males. Neutrophil TLR2 did not differ between sexes at baseline or following lipopolysaccharide (LPS) exposure. CD11b expression was higher in preterm male non-classical monocytes following Pam3CSK treatment when compared to females, a finding which is unique to our study. Preterm neonates had higher TLR2 expression at baseline in total monocytes, classical monocytes and non-classical monocytes than term. A sex difference was evident between preterm females and term females in TLR2 expression only. Hormone treatment showed no sex differences and there was no detectable difference between males and females in X-linked gene expression. Two miRNAs, miR-212-3p and miR-218-2-3p had significantly higher expression in preterm female than preterm male neonates. CONCLUSIONS: This study examined immune cell phenotypes and x-linked gene expression in preterm neonates and stratified according to gender. Our findings suggest that the responses of females mature with advancing gestation, whereas male term and preterm neonates have very similar responses. Female preterm neonates have improved monocyte activation than males, which likely reflects improved innate immune function as reflected clinically by their lower risk of sepsis. Dividing results by sex showed changes in preterm and term infants at baseline and following LPS stimulation, a difference which is reflected clinically by infection susceptibility. The sex difference noted is novel and may be limited to the preterm or early neonatal population as TLR2 expression on monocytes of older children does not differ between males and females. The differences shown in female and male innate immune cells likely reflect a superior innate immune defense system in females with sex differences in immune cell maturation. Existing human studies on sex differences in miRNA expression do not include preterm patients, and most frequently use either adult blood or cord blood. Our findings suggest that miRNA profiles are similar in neonates of opposite sexes at term but require further investigation in the preterm population. Our findings, while novel, provide only very limited insights into sex differences in infection susceptibility in the preterm population leaving many areas that require further study. These represent important areas for ongoing clinical and laboratory study and our findings represent an important contribution to exiting literature.

Effects of exercise on sex steroid hormones (estrogen, progesterone, testosterone) in eumenorrheic females: A systematic to review and meta-analysis.

BACKGROUND: The sex steroid hormones fluctuate during the menstrual cycle, which affects the strength and postural stability of females and leads to injuries and risk of falls. These hormones may be modulated by exercise to impact the overall health of females. OBJECTIVE: To determine the effects of exercise on sex steroid hormones in eumenorrheic females. METHODS: This review was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA) guidelines in Lahore, Pakistan. The full-length articles were searched using these databases/search engines (PubMed, Web of Science and Google Scholar, Sci-Hub). Randomized controlled trials along with single group experimental studies were also included. All types of exercises were compared with no exercise in the control group. The Cochrane Risk of Bias assessment tool assessed and screened the articles. The data were then analyzed. The primary outcomes were the levels of estrogen, progesterone and testosterone. RESULTS: Eleven studies were included (5 randomized controlled trials and 6 quasi-experimental studies). The effects of exercise on free estradiol concentration and serum progesterone level were not significant [p = 0.37 (SMD = 0.33, 95% CI = 0.14 to 0.74, I2 = 0%) and p = 0.84 (S.D= -0.65, C.I= -6.92 to 5.62, I2 = 94%)] respectively, whereas, the effects on testosterone levels were significant [p value < 0.00001 (M.D = 0.89, 95% C.I= -2.16 to 3.95, I2 = 94%)]. CONCLUSION: A blinded randomized controlled trial should be conducted in which a structured approach should be followed by women along with warm-ups, cool down and rest intervals. TRIAL REGISTRATION NUMBER: The systematic review was registered prospectively on PROSPERO with registration number CRD42023473767.

Sex hormones in COVID-19 severity: The quest for evidence and influence mechanisms.

Studies have reported variable effects of sex hormones on serious diseases. Severe disease and mortality rates in COVID-19 show marked gender differences that may be related to sex hormones. Sex hormones regulate the expression of the viral receptors ACE2 and TMPRSS2, which affect the extent of viral infection and consequently cause variable outcomes. In addition, sex hormones have complex regulatory mechanisms that affect the immune response to viruses. These hormones also affect metabolism, leading to visceral obesity and severe disease can result from complications such as thrombosis. This review presents the latest researches on the regulatory functions of hormones in viral receptors, immune responses, complications as well as their role in COVID-19 progression. It also discusses the therapeutic possibilities of these hormones by reviewing the recent findings of clinical and assay studies.