Aldo E. Calogero

Bio: Aldo E. Calogero is an academic researcher from University of Catania. The author has contributed to research in topics: Sperm & Male infertility. The author has an hindex of 56, co-authored 445 publications receiving 11092 citations. Previous affiliations of Aldo E. Calogero include National Institutes of Health.

A central nervous system defect in biosynthesis of corticotropin-releasing hormone is associated with susceptibility to streptococcal cell wall-induced arthritis in Lewis rats.

Abstract: We have recently found that susceptibility to streptococcal cell wall (SCW)-induced arthritis in Lewis (LEW/N) rats is due, in part, to defective inflammatory and stress mediator-induced activation of the hypothalamic-pituitary-adrenal (HPA) axis. Conversely, the relative arthritis resistance of histocompatible Fischer (F344/N) rats is related to their intact responses to the same stimuli. Specifically, LEW/N rats, in contrast to F344/N rats, have markedly impaired plasma corticotropin and corticosterone responses to SCW, recombinant human interleukin 1 alpha, the serotonin agonist quipazine, or synthetic rat/human corticotropin-releasing hormone (CRH). To explore the mechanism of this defect, we examined the functional integrity of the hypothalamic CRH neuron in LEW/N rats compared to F344/N rats. LEW/N rats, in contrast to F344/N rats, showed profoundly deficient paraventricular nucleus CRH mRNA levels and hypothalamic CRH content in response to SCW. Compared to F344/N rats, there was no increase in LEW/N hypothalamic CRH content or CRH release from explanted LEW/N hypothalami in organ culture in response to recombinant interleukin 1 alpha. These data provide strong evidence that the defective LEW/N corticotropin and corticosterone responses to inflammatory and other stress mediators, and the LEW/N susceptibility to experimental arthritis, are due in part to a hypothalamic defect in the synthesis and secretion of CRH. The additional finding of deficient expression in LEW/N rats of the hypothalamic enkephalin gene, which is coordinately regulated with the CRH gene in response to stress, suggests that the primary defect is not in the CRH gene but is instead related to its inappropriate regulation.

Diabetes Mellitus and Sperm Parameters

Abstract: Because of the paucity of studies and inconsistencies regarding the impact of diabetes mellitus (DM) on semen quality, this disease is seldom looked for in the infertile patient. Recently, this view has been challenged by findings showing that DM induces subtle molecular changes that are important for sperm quality and function. This brief review shows the main sperm parameters in patients with DM and presents the mechanisms hypothesized to explain the changes observed in these patients. The data available suggest that DM alters conventional sperm parameters. In addition, DM causes histologic damage of the epididymis, with a negative impact on sperm transit. Various mechanisms may explain the sperm damage observed in patients with DM. These include endocrine disorders, neuropathy, and increased oxidative stress. Many authors suggest that DM decreases serum testosterone levels. This is associated with a steroidogenetic defect in Leydig cells. In addition, diabetic neuropathy seems to cause atonia of seminal vesicles, bladder, and urethra. Furthermore, DM is associated with an increased oxidative stress, which damages sperm nuclear and mitochondrial DNA. Finally, spermatogenesis derangement and germ cell apoptosis in type 1 DM may relate to a local autoimmune damage, whereas insulin resistance, obesity, and other related comorbidities may impair sperm parameters and decrease testosterone serum levels in patients with type 2 DM.

Interactions between tumor necrosis factor-α, hypothalamic corticotropin-releasing hormone, and adrenocorticotropin secretion in the rat

Abstract: We studied the effects of tumor necrosis factor-alpha (TNF alpha), a macrophage-derived pleiotropic cytokine produced during the inflammatory/immune response, on the function of the hypothalamic-pituitary-adrenal (HPA) axis of the rat. Intravenous injections of TNF alpha stimulated plasma ACTH and corticosterone secretion in a dose-dependent fashion. This effect was inhibited by a rat CRH antiserum that was administered to the rats 1 h before the TNF alpha injections. This suggested that CRH is a major mediator of the HPA axis response to TNF alpha. We subsequently evaluated the ability of TNF alpha to influence CRH and ACTH secretion in vitro by explanted rat hypothalami in organ culture and by dispersed rat anterior pituicytes in primary culture respectively. Hypothalami were incubated for 40 min with graded concentrations of TNF alpha (10 pM to 1 microM). This cytokine stimulated CRH secretion in a dose-dependent fashion, with an EC50 of 6.7 x 10 pM (P less than 0.05). Preincubation of hypothalamic explants with dexamethasone, indomethacin (1 microM), eicosatetraynoic acid (10 microM), or nordihydroguaiaretic acid (30 microM) resulted in inhibition of TNF alpha-stimulated CRH secretion (P less than 0.05). Interestingly, 4-h incubation with TNF alpha had no effect on ACTH secretion from rat anterior pituicytes at a concentration of 10 nM. Higher concentrations of TNF alpha (100 nM and 1 microM), however, elicited a dose-dependent increase in the ACTH concentration in the medium. Our results suggest that TNF alpha represents one of the immune response mediators that directly or via stimulation of other cytokines act as activators of the HPA axis during immune/inflammatory reactions. This effect appears to be glucocorticoid suppressible and eicosanoid mediated. The primary site of action of TNF alpha appears to by the hypothalamic CRH-secreting neuron. Some pituitary and adrenal effects of TNF alpha, however, cannot be excluded.

Sex-Specific SARS-CoV-2 Mortality: Among Hormone-Modulated ACE2 Expression, Risk of Venous Thromboembolism and Hypovitaminosis D.

Abstract: Severe acute respiratory syndrome coronavirus (SARS-CoV-2) disease (COVID-19) appears to have a higher mortality rate in presence of comorbidities and in men. The latter suggests the presence of a possible sex-dependent susceptibility. An enzymatic system involved in this different predisposition could be represented by angiotensin converting enzyme 2 (ACE2). ACE2 is activated and down-regulated by the spike protein of the virus and allows the penetration of SARS-CoV-2 into epithelial cells and myocardium. Data on the experimental animal have shown that 17s-estradiol increases the expression and activity of ACE2 in both adipose tissue and kidney. Spontaneously hypertensive male mice have a higher myocardial ACE2 expression than females and its levels decrease after orchiectomy. In addition to this first aspect, the recent evidence of an increased frequency of venous thromboembolism in patients with COVID-19 (a clinical element associated with a worse prognosis) calls the attention on the safety of treatment with testosterone, in particular in hypogonadal men with greater genetic predisposition. Evidence that sex hormones are able to modulate the expression of ACE2 could help in interpreting epidemiological results and in designing more appropriate intervention strategies. Moreover, the vitamin D deficiency in elderly men may be worthy of further study regarding the epidemiological aspects of this different susceptibility and lethality between sexes.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Standards of Medical Care in Diabetes

Abstract: XI. STRATEGIES FOR IMPROVING DIABETES CARE D iabetes is a chronic illness that requires continuing medical care and patient self-management education to prevent acute complications and to reduce the risk of long-term complications. Diabetes care is complex and requires that many issues, beyond glycemic control, be addressed. A large body of evidence exists that supports a range of interventions to improve diabetes outcomes. These standards of care are intended to provide clinicians, patients, researchers, payors, and other interested individuals with the components of diabetes care, treatment goals, and tools to evaluate the quality of care. While individual preferences, comorbidities, and other patient factors may require modification of goals, targets that are desirable for most patients with diabetes are provided. These standards are not intended to preclude more extensive evaluation and management of the patient by other specialists as needed. For more detailed information, refer to Bode (Ed.): Medical Management of Type 1 Diabetes (1), Burant (Ed): Medical Management of Type 2 Diabetes (2), and Klingensmith (Ed): Intensive Diabetes Management (3). The recommendations included are diagnostic and therapeutic actions that are known or believed to favorably affect health outcomes of patients with diabetes. A grading system (Table 1), developed by the American Diabetes Association (ADA) and modeled after existing methods, was utilized to clarify and codify the evidence that forms the basis for the recommendations. The level of evidence that supports each recommendation is listed after each recommendation using the letters A, B, C, or E.

How do glucocorticoids influence stress responses? Integrating permissive, suppressive, stimulatory, and preparative actions.

Abstract: The secretion of glucocorticoids (GCs) is a classic endocrine response to stress. Despite that, it remains controversial as to what purpose GCs serve at such times. One view, stretching back to the time of Hans Selye, posits that GCs help mediate the ongoing or pending stress response, either via basal levels of GCs permitting other facets of the stress response to emerge efficaciously, and/or by stress levels of GCs actively stimulating the stress response. In contrast, a revisionist viewpoint posits that GCs suppress the stress response, preventing it from being pathologically overactivated. In this review, we consider recent findings regarding GC action and, based on them, generate criteria for determining whether a particular GC action permits, stimulates, or suppresses an ongoing stressresponse or, as an additional category, is preparative for a subsequent stressor. We apply these GC actions to the realms of cardiovascular function, fluid volume and hemorrhage, immunity and inflammation, metabolism, neurobiology, and reproductive physiology. We find that GC actions fall into markedly different categories, depending on the physiological endpoint in question, with evidence for mediating effects in some cases, and suppressive or preparative in others. We then attempt to assimilate these heterogeneous GC actions into a physiological whole. (Endocrine Reviews 21: 55‐ 89, 2000)

Protective and Damaging Effects of Stress Mediators

Abstract: Over 60 years ago, Selye1 recognized the paradox that the physiologic systems activated by stress can not only protect and restore but also damage the body. What links these seemingly contradictory roles? How does stress influence the pathogenesis of disease, and what accounts for the variation in vulnerability to stress-related diseases among people with similar life experiences? How can stress-induced damage be quantified? These and many other questions still challenge investigators. This article reviews the long-term effect of the physiologic response to stress, which I refer to as allostatic load.2 Allostasis — the ability to achieve stability through change3 — . . .

Stress, adaptation, and disease. Allostasis and allostatic load.

Abstract: Adaptation in the face of potentially stressful challenges involves activation of neural, neuroendocrine and neuroendocrine-immune mechanisms. This has been called "allostasis" or "stability through change" by Sterling and Eyer (Fisher S., Reason J. (eds): Handbook of Life Stress, Cognition and Health. J. Wiley Ltd. 1988, p. 631), and allostasis is an essential component of maintaining homeostasis. When these adaptive systems are turned on and turned off again efficiently and not too frequently, the body is able to cope effectively with challenges that it might not otherwise survive. However, there are a number of circumstances in which allostatic systems may either be overstimulated or not perform normally, and this condition has been termed "allostatic load" or the price of adaptation (McEwen and Stellar, Arch. Int. Med. 1993; 153: 2093.). Allostatic load can lead to disease over long periods. Types of allostatic load include (1) frequent activation of allostatic systems; (2) failure to shut off allostatic activity after stress; (3) inadequate response of allostatic systems leading to elevated activity of other, normally counter-regulated allostatic systems after stress. Examples will be given for each type of allostatic load from research pertaining to autonomic, CNS, neuroendocrine, and immune system activity. The relationship of allostatic load to genetic and developmental predispositions to disease is also considered.