Evaluating the relationship of in utero nicotine exposure with hypoglycemia after delivery: An observational study.

BACKGROUND: Hypoglycemia in neonates is common and contributes to 4.0-5.8% of neonatal intensive care unit (NICU) admissions. In utero nicotine exposure is underexplored as a potential contributor to neonatal hypoglycemia. Rat models have shown that in utero nicotine exposure can be associated with a reduction in pancreatic beta cell mass, leading to glucose dysregulation. The primary aim of this work is to study the risk of developing hypoglycemia after birth in a population of in utero nicotine-exposed neonates. METHODS: We conducted a retrospective matched cohort study that augmented an existing dataset of neonates admitted to a level IV NICU with household-based in utero nicotine exposure (N = 335). Neonates in the control group parents denied household smoking (N = 325), were born within a 6-month timeframe, and were within a birthweight of 50 grams of a nicotine-exposed neonate. Data reviewed included gestational age, growth parameters, maternal history of diabetes, and glucose levels within the first three hours of life per unit protocol. RESULTS: 660 neonates were included in the analysis. In utero nicotine exposure demonstrated a 94.3% posterior probability (PP) for greater hypoglycemia risk (RR = 1.185, 95% CrI = [0.953, 1.445]). A 94.6% PP was demonstrated when neonates who were small for gestational age, intrauterine growth-restricted, and born to diabetic mothers were excluded (n = 482; RR = 1.271, 95% CrI = [0.946, 1.669]). CONCLUSION: Nicotine exposure in utero was found to be a potential risk factor for developing hypoglycemia after birth. Mechanisms of action should be explored, and additional research on in utero nicotine exposure risks should follow.

Defining recurrence of nonmelanoma skin cancer after Mohs micrographic surgery: Report of the American College of Mohs Surgery Registry and Outcomes Committee.

BACKGROUND: Standardized definitions and methods of surveillance for local recurrence of nonmelanoma skin cancer are critical in determining cure rates attributed to treatment modalities. OBJECTIVE: We sought to offer a standard definition of local recurrence after surgical treatment of nonmelanoma skin cancer and to propose an acceptable surveillance period and tracking methods. METHODS: A literature search was performed for background definitions of local recurrence and tracking methods. The American College of Mohs Surgery (ACMS) Registry and Outcomes Committee then conducted a modified Delphi process to arrive at consensus definitions. RESULTS: We define local recurrence as a tumor with comparable histology, with contiguity to the surgical scar after treatment, and that arises within the area of the previously treated tumor. LIMITATIONS: This project reports the results of a modified Delphi method process involving members of the ACMS. The model described may not be useful for nonexcision type treatments such as topical chemotherapy, electrodessication and curettage, or radiation treatment. CONCLUSIONS: Previous definitions of recurrence and surveillance methods after surgical treatment of nonmelanoma skin cancer are variable and nonstandard. We describe consensus standards for defining and tracking recurrence that should allow for consistent scientific evaluation and development of performance data in skin cancer outcomes registries.

The production of alpha/beta and gamma/delta double negative (DN) T-cells and their role in the maintenance of pregnancy.

The ability of the thymus gland to convert bone marrow-derived progenitor cells into single positive (SP) T-cells is well known. In this review we present evidence that the thymus, in addition to producing SP T-cells, also has a pathway for the production of double negative (DN) T-cells. The existence of this pathway was noted during our examination of relevant literature to determine the cause of sex steroid-induced thymocyte loss. In conducting this search our objective was to answer the question of whether thymocyte loss is the end product of a typical interaction between the reproductive and immune systems, or evidence that the two systems are incompatible. We can now report that "thymocyte loss" is a normal process that occurs during the production of DN T-cells. The DN T-cell pathway is unique in that it is mediated by thymic mast cells, and becomes functional following puberty. Sex steroids initiate the development of the pathway by binding to an estrogen receptor alpha located in the outer membrane of the mast cells, causing their activation. This results in their uptake of extracellular calcium, and the production and subsequent release of histamine and serotonin. Lymphatic vessels, located in the subcapsular region of the thymus, respond to the two vasodilators by undergoing a substantial and preferential uptake of gamma/delta and alpha/beta DN T- cells. These T- cells exit the thymus via efferent lymphatic vessels and enter the lymphatic system.The DN pathway is responsible for the production of three subsets of gamma/delta DN T-cells and one subset of alpha/beta DN T-cells. In postpubertal animals approximately 35 % of total thymocytes exit the thymus as DN T-cells, regardless of sex. In pregnant females, their levels undergo a dramatic increase. Gamma/delta DN T-cells produce cytokines that are essential for the maintenance of pregnancy.

Co-treatment with the non-steroidal anti-androgen drug, flutamide and the natural estrogen, 17ß-estradiol does not lead to additive reproductive impairment in juvenile Murray rainbowfish (Melanotaenia fluviatilis).

The aim of this study was to investigate if the anti-androgen, flutamide, and the estrogen, 17ß-estradiol work together to feminize juvenile Murray rainbowfish (Melanotaenia fluviatilis). Fish (60 days post-hatch) were exposed to 25 ng/L 17ß-estradiol (E2), 25 µg/L flutamide (Flu low), 250 µg/L flutamide (Flu high), E2 + Flu low and E2 + Flu high. After 35 days of exposure, concentrations of sex steroid hormones, 17ß-estradiol and 11-keto testosterone (11-KT), were determined in the head; and vitellogenin (VTG) concentration was measured in the tail. The abdomens were used for histological investigation of the gonads. Treatment with E2 + Flu high resulted in reduction in body weights and lengths in males and condition factor in females. Intersex was noted in Flu high and E2 + Flu high treatments. Exposures to E2 and/or Flu (low and high) resulted in precocious oocyte development but inhibited sperm development. The 17ß-estradiol levels decreased significantly in the heads of both sexes after exposures to E2 and/or Flu (high and low). Flu high and E2 alone increased the 11-KT levels in both sexes. However, E2 + Flu low decreased 11-KT levels in males and increased them in females. Flutamide (low and high) induced VTG protein in the tails of both sexes. In males, VTG was not induced in the tail after exposure to E2. No significant effect of flutamide on E2-induced VTG concentration was noted. We conclude that co-treatment with flutamide and 17ß-estradiol does not lead to additive reproductive impairment in juvenile Murray rainbowfish.

Long-term exposures to di-n-butyl phthalate inhibit body growth and impair gonad development in juvenile Murray rainbowfish (Melanotaenia fluviatilis).

The aim of the present study was to evaluate whether long-term exposures to environmentally relevant concentrations of di-n-butyl phthalate (DnBP) disrupt the reproduction-based endpoints in juvenile Murray rainbowfish (Melanotaenia fluviatilis). Fish were exposed to 5, 15 or 50 µg l(-1) DnBP for 30, 60 and 90 days each, and the effects on survival, body growth, whole-body concentrations of sex steroid hormones and gonadal development were investigated. The lowest observed effective concentration to affect the condition factor after 90 days was 5 µg l(-1). Complete feminization of the gonad was noted in fish exposed to 5 µg l(-1) for 90 days and to 15 and 50 µg l(-1) of DnBP for 30 or 60 days. After 90 days of exposure to DnBP, the ovaries were regressed and immature as opposed to the control fish which were in early-vitellogenic stage. Testes, present only in fish exposed to 5 µg l(-1) of DnBP for 30 or 60 days, were immature in comparison to the control fish that contained testes in the mid-spermatogenic phase. The E2/11-KT ratio was significantly higher only after exposures to 5 µg l(-1) DnBP for 90 days and 50 µg l(-1) DnBP for 30 days. Our data suggest that exposures to 5 µg l(-1) DnBP for 30 days did not have profound effects on body growth and gonadal differentiation of fish. However, 30 days of exposure to 15 µg l(-1) could interfere with the gonad development and to 50 µg l(-1) could compromise the hormonal profile of juvenile fish.

Effects of short-term exposure to the model anti-androgen, flutamide on reproductive function based endpoints in female Murray rainbowfish (Melanotaenia fluviatilis).

The aim of the present study was to evaluate the responses of female Murray rainbowfish (Melanotaenia fluviatilis) to the model anti-androgen, flutamide in a short-term exposure. Adult female Murray rainbowfish were exposed to nominal (measured) concentrations of 125 (104), 250 (163), 500 (378) and 1000 (769) µg/L of flutamide for seven days in a semi-static set-up. Plasma vitellogenin (VTG), 11-keto testosterone (11-KT) and 17ß-estradiol (E2) concentrations, brain aromatase activity and ovarian histology were assessed following the exposure. No treatment-related mortality was found in rainbowfish and there was no effect of flutamide on the developmental stage of the ovaries. Histological investigation revealed absence of mature oocytes in flutamide-treated fish. In addition, a significant reduction in the sizes of the vitellogenic oocytes was found after treatment with 500 and 1000 µg/L flutamide. The circulating levels of VTG and the activity of aromatase in the brain were also significantly reduced in fish treated with 500 and 1000 µg/L flutamide. Treatment with higher concentrations of flutamide reduced the levels of 11-KT and E2 in plasma. The results from this study demonstrate that a short-term exposure to the model anti-androgen, flutamide can adversely affect the reproductive function based on end-points such as plasma VTG, 11-KT and E2; brain aromatase activity and sizes of the oocytes in female Murray rainbowfish. Further, a positive correlation between these experimental variables suggests hormonal imbalance.

The estrogen-injected female mouse: new insight into the etiology of PCOS.

BACKGROUND: Female mice and rats injected with estrogen perinatally become anovulatory and develop follicular cysts. The current consensus is that this adverse response to estrogen involves the hypothalamus and occurs because of an estrogen-induced alteration in the GnRH delivery system. Whether or not this is true has yet to be firmly established. The present study examined an alternate possibility in which anovulation and cyst development occurs through an estrogen-induced disruption in the immune system, achieved through the intermediation of the thymus gland. METHODS, RESULTS AND CONCLUSION: A putative role for the thymus in estrogen-induced anovulation and follicular cyst formation (a model of PCOS) was examined in female mice by removing the gland prior to estrogen injection. Whereas all intact, female mice injected with 20 microg estrogen at 5-7 days of age had ovaries with follicular cysts, no cysts were observed in animals in which thymectomy at 3 days of age preceded estrogen injection. In fact, after restoring immune function by thymocyte replacement, the majority of thymectomized, estrogen-injected mice had ovaries with corpora lutea. Thus, when estrogen is unable to act on the thymus, ovulation occurs and follicular cysts do not develop. This implicates the thymus in the cysts' genesis and discounts the role of the hypothalamus. Subsequent research established that the disease is transferable by lymphocyte infusion. Transfer took place between 100-day-old estrogen-injected and 15-day-old naïve mice only when recipients were thymectomized at 3 days of age. Thus, a prerequisite for cyst formation is the absence of regulatory T cells. Their absence in donor mice was judged to be the result of an estrogen-induced increase in the thymus' vascular permeability, causing de facto circumvention of the final stages of regulatory T cell development. The human thymus has a similar vulnerability to steroid action during the fetal stage. We propose that in utero exposure to excessive levels of steroids such as estrogen has a long-term effect on the ability of the thymus to produce regulatory T cells. In female offspring this can lead to PCOS.

Mitochondrial 3 beta-hydroxysteroid dehydrogenase (HSD) is essential for the synthesis of progesterone by corpora lutea: an hypothesis.

In mouse ovaries, the enzyme 3 beta-hydroxysteroid dehydrogenase (HSD) is distributed between microsomes and mitochondria. Throughout the follicular phase of the estrous cycle, the HSD activity in microsomes is predominant; whereas, after LH stimulation, HSD activity during the luteal phase is highest in the mitochondria. The current study examined whether or not LH stimulation always results in an increase in mitochondrial HSD activity. This was accomplished by measuring the HSD activity in microsomal and mitochondrial fractions from ovaries of pregnant mice. These animals have two peaks of LH during gestation, and one peak of LH after parturition. It was found that mitochondrial HSD activity was highest after each peak of LH. It is proposed that mitochondrial HSD is essential for the synthesis of high levels of progesterone. The increase in HSD activity in mitochondria after LH stimulation occurs because: 1) LH initiates the simultaneous synthesis of HSD and the cholesterol side-chain cleavage enzyme (P450scc); and, 2) HSD and P450scc bind together to form a complex, which becomes inserted into the inner membrane of the mitochondria. High levels of progesterone are synthesized by mitochondrial HSD because: 1) the requisite NAD+ cofactor for progesterone synthesis is provided directly by the mitochondria, rather than indirectly via the rate limiting malate-aspartate shuttle; and, 2) the end-product inhibition of P450scc by pregnenolone is eliminated because pregnenolone is converted to progesterone.

Proposed mechanism for sperm chromatin condensation/decondensation in the male rat.

Condensation of sperm chromatin occurs after spermatozoa have left the caput epididymis and are in transit to the cauda epididymis, during which time large numbers of disulfide bonds are formed. The formation of these disulfide bonds requires the repeated oxidation of the cofactor, NAD(P)H. To date, the means by which this oxidation is achieved has yet to be elucidated. Spermatozoa lose the bulk of their cytoplasm prior to leaving the testis; and, as a result, any shuttle systems for removing and transferring reducing equivalents into the mitochondria are unlikely to be operational. In an apparent preparation for the loss of cytoplasm, however, the following events occur during spermatogenesis. First, androgen-binding protein (ABP) is produced by the Sertoli cells of the testis; second, high affinity binding sites for ABP are inserted into the membrane surrounding the nucleus; and third, a nuclear location is acquired for the enzyme, 3alpha-hydroxysteroid dehydrogenase (3alpha-HSD). We propose that after the loss of cytoplasm, the nuclear region of spermatozoa is directly accessible to constituents contained in the lumen of the caput epididymis. As a consequence, luminal ABP attaches itself to the nuclear membrane via its binding sites, and is internalized. After internalization, ABP exerts its principle function, which is to bind to luminal 5alpha-dihydrotestosterone (5alpha-DHT), thereby ensuring its availability to the enzyme, 3alpha-HSD. In the conversion of 5alpha-DHT to 3alpha-androstanediol (3alpha-Diol), NAD(P)H is oxidized. Spermatozoa that reach the cauda epididymis have fully condensed chromatin. In addition, the nuclear region retains appreciable amounts of 5alpha-DHT and 3alpha-Diol, both bound to ABP. During fertilization, the bound 3alpha-Diol is converted back to 5alpha-DHT, reducing equivalents are transferred to NAD(P)+, and disulfide bonds are broken.IVF clinics report that spermatozoa with incompletely condensed chromatin have a low percentage of fertilization. If our proposed mechanism for chromatin condensation/decondensation is borne out by further research, IVF clinics might consider preincubating spermatozoa with 5alpha-DHT in order to increase the efficiency of fertilization.

The administration of cortisone to female B6A mice during their immune adaptive period causes anovulation and the formation of ovarian cysts.

PROBLEM: Female mice that are injected with estradiol-17beta (E2) and testosterone during the 7-day immune adaptive period are infertile at adulthood. To determine whether the resultant infertility can be caused by steroids other than estrogens/ androgens, this study examined the effect of injecting cortisone, alone, and in combination with E2 and testosterone, on reproductive function. METHOD OF STUDY: Neonatal (C57BL/6J x A/J)F1 B6A female mice were injected from 3 to 6 days of age with sesame oil:ethanol (9:1; v:v), alone, or containing 20 microgg cortisone acetate, 20 microg E2, or 20 microg testosterone. Two additional groups were given 20 microg cortisone acetate in combination with 20 microg E2 or 20 microg testosterone. At adulthood the animals were killed, the stage of vaginal estrus determined, the ovaries examined for the presence of corpora lutea and follicular cysts, and circulating levels of progesterone, E2, and testosterone were measured by radioimmunoassay (RIA). RESULTS: It was found that injections of cortisone seriously compromise reproductive development. For example, 11% of cortisone-injected animals had ovaries that lacked corpora lutea. In addition, 39% of cortisone-injected females had ovaries with follicular cysts. Cortisone-injected females also had low levels of circulating progesterone (18 ng/mL versus 30 ng/mL for the sesame oil-injected females). CONCLUSION: It is concluded that the deleterious effect of steroids on reproductive function, when administered during the immune adaptive period, is not restricted to estrogens and androgens. It is proposed that injections of cortisone alter T-lymphocyte subsets, which contributes to anovulation and the production of follicular cysts.