Alteration of epigenetic methyl and acetyl marks by postnatal chromium(VI) exposure causes apoptotic changes in the ovary of the F1 offspring

Hexavalent chromium, Cr(VI), is a heavy metal endocrine disruptor used widely in various industries worldwide and is considered a reproductive toxicant. Our previous studies demonstrated that lactational exposure to Cr(VI) caused follicular atresia, disrupted steroid hormone biosynthesis and signaling, and delayed puberty. However, the underlying mechanism was unknown. The current study investigated the effects of Cr(VI) exposure (25 ppm) during postnatal days 1-21 via dam's milk on epigenetic alterations in the ovary of F1 offspring. Data indicated that Cr(VI) disrupted follicle development and caused apoptosis by increasing DNMT3a /3b and histone methyl marks (H3K27me3 and H3K9me3) along with decreasing histone acetylation marks (H3K9ac and H3K27ac). Our study demonstrates that exposure to Cr(VI) causes changes in the epigenetic marks, partially contributing to the transcriptional repression of genes regulating ovarian development, cell proliferation (PCNA), cell survival (BCL-XL and BCL-2), and activation of genes regulating apoptosis (AIF and cleaved caspase-3), resulting in follicular atresia. The current study suggests a role for epigenetics in Cr(VI)-induced ovotoxicity and infertility.

Inhibition of Sirtuin-1 hyperacetylates p53 and abrogates Sirtuin-1-p53 interaction in Cr(VI)-induced apoptosis in the ovary

Environmental contamination with hexavalent chromium, Cr(VI), has been increasing in the United States as well as in developing countries. Exposure to Cr(VI) predisposes the human population to various diseases, including cancer, infertility, and developmental problems in children. Previous findings from our laboratory reported that prenatal exposure to Cr(VI) caused premature ovarian failure through p53-mediated mechanisms. Sirtuin 1 (SIRT1) is an NAD+ -dependent histone deacetylase class III. SIRT1 deacetylates several histones and non-histone proteins such as p53 and NFkB. The current study determines a role for the SIRT1-p53 network in apoptosis induced by Cr(VI) in the ovary and establishes physical interaction between SIRT1 and p53. Adult pregnant dams were given regular drinking water or Cr(VI) (10 ppm potassium dichromate in drinking water, ad libitum), and treated with SIRT1 inhibitor, EX-527 (50 mg/kg body weight, i.p.,), during 9.5 - 14.5 days post-coitum. On postnatal day-1, ovaries from F1 offspring were collected for various analyses. Results indicated that Cr(VI) increased germ cell and somatic cell apoptosis, upregulated acetyl-p53, activated the apoptotic pathway, and inhibited cell survival pathways. Cr(VI) decreased acetyl-p53-SIRT1 co-localization in the ovary. In an immortalized rat granulosa cell line SIGC, Cr(VI) inhibited the physical interaction between SIRT1 and acetyl-p53 by altering the p53:SIRT1 ratio. EX-527 exacerbated Cr(VI)-induced mechanisms. The current study shows a novel mechanism for Cr(VI)-induced apoptosis in the ovary, mediated through the p53-SIRT1 network, suggesting that targeting the p53 pathway may be an ideal approach to rescue ovaries from Cr(VI)-induced apoptosis.

Gestational Exposure to Ultrafine Particles Reveals Sex- and Dose-Specific Changes in Offspring Birth Outcomes, Placental Morphology, and Gene Networks

Particulate matter (PM) causes adverse developmental outcomes following prenatal exposure, but the underlying biological mechanisms remain uncertain. Here we elucidate the effects of diesel exhaust ultrafine particle (UFP) exposure during pregnancy on placental and fetal development. Time-mated C57Bl/6n mice were gestationally exposed to UFPs at a low dose (LD, 100 µg/m3) or high dose (HD, 500 µg/m3) for 6 h daily. Phenotypic effects on fetuses and placental morphology at gestational day (GD) of 18.5 were evaluated, and RNA sequencing was characterized for transcriptomic changes in placental tissue from male and female offspring. A significant decrease in average placental weights and crown to rump lengths was observed in female offspring in the LD exposure group. Gestational UFP exposure altered placental morphology in a dose- and sex-specific manner. Average female decidua areas were significantly greater in the LD and HD groups. Maternal lacunae mean areas were increased in the female LD group, whereas fetal blood vessel mean areas were significantly greater in the male LD and HD groups. RNA sequencing indicated several disturbed cellular functions related to lipid metabolism, which were most pronounced in the LD group and especially in female placental tissue. Our findings demonstrate the vulnerability of offspring exposed to UFPs during pregnancy, highlighting sex-specific effects and emphasizing the importance of mitigating PM exposure to prevent adverse health outcomes.

Radiation therapy for vaginal and perirectal lesions in recurrent ovarian cancer

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Radiation to isolated vaginal and perirectal ovarian cancer recurrences provides effective in-field control.

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Complete response of targeted lesions after radiation was 88%.

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Radiation increased the chemotherapy-free interval without associated grade 3/4 toxicities.

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Platinum sensitivity prior to radiation may be associated with improved overall survival.

The role for localized radiation to treat ovarian cancer (OC) patients with locally recurrent vaginal/perirectal lesions remains unclear, though we hypothesize these patients may be salvaged locally and gain long-term survival benefit. We describe our institutional outcomes using intensity modulated radiation therapy (IMRT) +/- high-dose rate (HDR) brachytherapy to treat this population. Our primary objectives were to evaluate complete response rates of targeted lesions after radiation and calculate our 5-year in-field control (IFC) rate. Secondary objectives were to assess radiation-related toxicities, chemotherapy free-interval (CFI), as well as post-radiation progression-free (PFS) and overall survival (OS). PFS and OS were defined from radiation start to either progression or death/last follow-up, respectively. This was a heavily pre-treated cohort of 17 recurrent OC patients with a median follow-up of 28.4 months (range 4.5–166.4) after radiation completion. 52.9% had high-grade serous histology and 4 (23.5%) had isolated vaginal/perirectal disease. Four (23.5%) patients had in-field failures at 3.7, 11.2, 24.5, and 27.5 months after start of radiation, all treated with definitive dosing of radiation therapy. Patients who were platinum-sensitive prior to radiation had similar median PFS (6.5 vs. 13.4 months, log-rank p = 0.75), but longer OS (71.1 vs 18.8 months, log-rank p = 0.05) than their platinum-resistant counterparts. Excluding patients with low-grade histology or who were treated with palliative radiation, median CFI was 14.2 months (range 4.7 – 33.0). Radiation was well tolerated with 2 (12.0%) experiencing grade 3/4 gastrointestinal/genitourinary toxicities. In conclusion, radiation to treat locally recurrent vaginal/perirectal lesions in heavily pre-treated OC patients is safe and may effectively provide IFC.

The Functional Significance of Endocrine-immune Interactions in Health and Disease

Hormones are known to influence various body systems that include skeletal, cardiac, digestive, excretory, and immune systems. Emerging investigations suggest the key role played by secretions of endocrine glands in immune cell differentiation, proliferation, activation, and memory attributes of the immune system. The link between steroid hormones such as glucocorticoids and inflammation is widely known. However, the role of peptide hormones and amino acid derivatives such as growth and thyroid hormones, prolactin, dopamine, and thymopoietin in regulating the functioning of the immune system remains unclear. Here, we reviewed the findings pertinent to the functional role of hormone-immune interactions in health and disease and proposed perspective directions for translational research in the field.

Sexually Dimorphic Impact of Chromium Accumulation on Human Placental Oxidative Stress and Apoptosis

Environmental contamination with hexavalent chromium (CrVI) is a growing problem both in the United States and developing countries. Hexavalent chromium is widely used in numerous industries. Environmental exposure to CrVI adversely affects pregnancy outcomes and subsequent health of 2 generations, resulting in higher pregnancy loss, spontaneous abortion and low birth rate. Pregnant women exposed to CrVI through occupational settings experience increased risk of spontaneous abortion, stillbirth, preterm birth, and neonatal death. Children of the CrVI exposed women experience respiratory problems, perinatal jaundice, and increased birth defects. Because placental dysfunction may have a role in such adverse pregnancy outcome, we tested the hypothesis that environmental Cr exposure in pregnant women results in Cr accumulation in the human placenta, which could increase placental oxidative stress by disrupting antioxidant machinery and inducing apoptosis. Studies using frozen, deidentified human term placenta samples indicated that: (1) Cr accumulates in human term placenta tissues and (2) increase in Cr accumulation is positively correlated with oxidative stress and apoptotic markers, and altered antioxidants levels. Interestingly, there was a sexual dimorphism in the correlation between Cr accumulation and oxidative stress, and expression of apoptotic and antioxidant markers. Mechanistic in vitro studies using human trophoblast cells BeWo confirmed the detrimental effects of Cr in altering antioxidant genes. For the first time, this study provides evidence in support of a positive correlation between Cr accumulation in the human placenta and accelerated oxidative stress, with a gender bias toward the male sex.

Ex Vivo Fetal Whole Ovarian Culture Model: An Essential Tool for Studies in Reproductive Toxicology and Pharmacology

Major limitations in understanding the direct effects of endocrine-disrupting chemicals (EDCs) and cell signaling events in ovarian cellular dynamics in mammals include a lack of proper and simple tools/techniques as well as gaps in knowledge regarding the critical window(s) of vulnerability. Identifying and validating such tools and evaluating the effects of EDCs on molecular dynamics and cellular events during the critical windows of ovarian development are very important to improve the fertility in women and preserve the future health of the developing fetuses. Therefore, we developed a fetal whole ovarian ex vivo culture model. Ex vivo ovary culture models allow varying culture parameters in a highly controlled manner and thus have the potential to allow a more thorough evaluation for reproductive toxicity studies and drug response. This chapter describes clear and thorough details for setting up and maintaining an ex vivo culture system from the rat ovaries and further analyses of mRNA and protein expressions and estimating follicle numbers.

Editor's Highlight: Exposure to CrVI during Early Pregnancy Increases Oxidative Stress and Disrupts the Expression of Antioxidant Proteins in Placental Compartments

Epidemiologic studies document relationships between chromium VI (CrVI) exposure and increased risk of spontaneous abortion, stillbirth, preterm birth, and neonatal death in pregnant women. Environmental contamination with CrVI is a growing problem both in the United States and developing countries. CrVI is widely used in numerous industries. This study was designed to understand the mechanism of CrVI toxicity on placental oxidative stress and antioxidant (AOX) machinery. Pregnant mother rats were treated with or without CrVI (50 ppm K2Cr2O7) through drinking water from gestational day (GD) 9.5-14.5, and placentas were analyzed on GD 18.5. Results indicated that CrVI reduced the trophoblast cell population. CrVI increased reactive oxygen species (ROS) and decreased the expression of AOX proteins. CrVI disrupts the trophoblast proliferation of the placenta. This study provides insight into the critical role of AOXs in placental function.

Resveratrol protects the ovary against chromium-toxicity by enhancing endogenous antioxidant enzymes and inhibiting metabolic clearance of estradiol

Resveratrol (RVT), a polyphenolic component in grapes and red wine, has been known for its cytoprotective actions against several diseases. However, beneficial effects of RVT against early exposure to endocrine disrupting chemicals (EDCs) have not been understood. EDCs are linked to several ovarian diseases such as premature ovarian failure, polycystic ovary syndrome, early menopause and infertility in women. Hexavalent chromium (CrVI) is a heavy metal EDC, and widely used in >50 industries. Environmental contamination with CrVI in the US is rapidly increasing, predisposing the human to several illnesses including cancers and still birth. Our lab has been involved in determining the molecular mechanism of CrVI-induced female infertility and intervention strategies to mitigate CrVI effects. Lactating mother rats were exposed to CrVI (50ppm potassium dichromate) from postpartum days 1-21 through drinking water with or without RVT (10mg/kg body wt., through oral gavage daily). During this time, F1 females received respective treatments through mother's milk. On postnatal day (PND) 25, blood and the ovary, kidney and liver were collected from the F1 females for analyses. CrVI increased atresia of follicles by increasing cytochrome C and cleaved caspase-3; decreasing antiapoptotic proteins; decreasing estradiol (E2) biosynthesis and enhancing metabolic clearance of E2, increasing oxidative stress and decreasing endogenous antioxidants. RVT mitigated the effects of CrVI by upregulating cell survival proteins and AOXs; and restored E2 levels by inhibiting hydroxylation, glucuronidation and sulphation of E2. This is the first study to report the protective effects of RVT against any toxicant in the ovary.

Cissus quadrangularis prevented the ovariectomy induced oxidative stress in the femur of adult albino rats

The increasing evidence suggesting the role of free radicals in bone resorption and bone loss prompted us to explore whether the consumption of antioxidant rich medicinal plant C. quadrangularis modifies antioxidant status in ovariectomized rats.

METHODS

Twenty four female adult rats, 90days old showing regular estrous cycles were used for the present study. The animals were divided into two groups. The Group-1 rats (n=6) were sham operated and Group-II rats were bilaterally ovariectomized (n=18) and treated with C. quadrangularis for sixty days (100mg/kg body weight and 250mg/kg body weight). After sixty days, the rats were killed, femora were dissected out, minced and homogenized in Tris-HCl buffer (pH 7.4) and the supernatant was collected and used for biochemical assays.

RESULTS

Ovariectomy registered a decrease (p<0.05) in the activities of SOD, GPx, GST, ALP, collagen content and increased (p<0.05) the activities of TRAP and lipid peroxidation. Simultaneous administration of C. quadrangularis maintained the enzyme activities in ovariectomized rats.

CONCLUSION

C. quadrangularis, a natural herb may be used to treat the estrogen deficiency/menopause onset and ovariectomy induced oxidative stress.

A fetal whole ovarian culture model for the evaluation of CrVI-induced developmental toxicity during germ cell nest breakdown

Prenatal exposure to endocrine disrupting chemicals (EDCs), including bisphenol A, dioxin, pesticides, and cigarette smoke, has been linked to several ovarian diseases such as premature ovarian failure (POF) and early menopause in women. Hexavalent chromium (CrVI), one of the more toxic heavy metals, is widely used in more than 50 industries. As one of the world's leading producers of Cr compounds, the U.S. is facing growing challenges in protecting human health against adverse effects of CrVI. Our recent findings demonstrated that in vivo CrVI exposure during gestational period caused POF in F1 offspring. Our current research focus is three-fold: (i) to identify the effect of CrVI on critical windows of great vulnerability of fetal ovarian development; (ii) to understand the molecular mechanism of CrVI-induced POF; (iii) to identify potential intervention strategies to mitigate or inhibit CrVI effects. In order to accomplish these goals we used a fetal whole ovarian culture system. Fetuses were removed from the normal pregnant rats on gestational day 13.5. Fetal ovaries were cultured in vitro for 12 days, and treated with or without 0.1 ppm potassium dichromate (CrVI) from culture day 2-8, which recapitulated embryonic day 14.5-20.5, in vivo. Results showed that CrVI increased germ cell/oocyte apoptosis by increasing caspase 3, BAX, p53 and PUMA; decreasing BCL2, BMP15, GDF9 and cKIT; and altering cell cycle regulatory genes and proteins. This model system may serve as a potential tool for high throughput testing of various drugs and/or EDCs in particular to assess developmental toxicity of the ovary.

Lipid peroxidation and antioxidants status in human malignant and non-malignant thyroid tumours

Introduction:

Thyroid epithelial cells produce moderate amounts of reactive oxygen species that are physiologically required for thyroid hormone synthesis. Nevertheless, when they are produced in excessive amounts, they may become toxic.

Objective:

The present study is aimed to compare the lipid peroxidation (LPO), antioxidant enzymes – superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and non-protein thiols (reduced glutathione (GSH)) in human thyroid tissues with malignant and non-malignant disorders.

Design and Methods:

The study used human thyroid tissues and blood samples from 157 women (147 diseased and 10 normal). Thyroid hormones, oxidative stress markers and antioxidants were estimated by standard methods.

Results:

LPO significantly increased in most of the papillary thyroid carcinoma (PTC: 82.9%) and follicular thyroid adenoma (FTA: 72.9%) tissues, whilst in a majority of nodular goitre (69.2%) and Hashimoto’s thyroiditis (HT: 73.7%) thyroid tissues, it remained unaltered. GSH increased in PTC (55.3%), remained unaltered in FTA (97.3%) and all other goiter samples studied. SOD increased in PTC (51.1%) and all other malignant thyroid tissues studied. CAT remained unaltered in PTC (95.7%), FTA (97.3%) and all other non-malignant samples (HT, MNG, TMNG) studied. GPx increased in PTC (63.8%), all other malignant thyroid tissues and remained unaltered in many of the FTA (91.9%) tissues and all other non-malignant samples (HT, MNG, TMNG) studied.

Conclusions:

In the case of non-malignant thyroid tumours, the oxidant–antioxidant balance was undisturbed, whilst in malignant tumours the balance was altered, and the change in r value observed in the LPO and SOD pairs between normal and PTC tissues and also in many pairs with multi-nodular goitre (MNG)/toxic MNG tissues may be used as a marker to differentiate/detect different malignant/non-malignant thyroid tumours.

Identifying a novel role for X-prolyl aminopeptidase (Xpnpep) 2 in CrVI-induced adverse effects on germ cell nest breakdown and follicle development in rats

Environmental exposure to endocrine-disrupting chemicals (EDCs) is one cause of premature ovarian failure (POF). Hexavalent chromium (CrVI) is a heavy metal EDC widely used in more than 50 industries, including chrome plating, welding, wood processing, and tanneries. Recent data from U.S. Environmental Protection Agency indicate increased levels of Cr in drinking water from several American cities, which potentially predispose residents to various health problems. Recently, we demonstrated that gestational exposure to CrVI caused POF in F1 offspring. The current study was performed to identify the molecular mechanism behind CrVI-induced POF. Pregnant rats were treated with 25 ppm of potassium dichromate from Gestational Day (GD) 9.5 to GD 14.5 through drinking water, and the fetuses were exposed to CrVI through transplacental transfer. Ovaries were removed from the fetuses or pups on Embryonic Day (ED) 15.5, ED 17.5, Postnatal Day (PND) 1, PND 4, or PND 25, and various analyses were performed. Results showed that gestational exposure to CrVI: 1) increased germ cell/oocyte apoptosis and advanced germ cell nest (GCN) breakdown; 2) increased X-prolyl aminopeptidase (Xpnpep) 2, a POF marker in humans, during GCN breakdown; 3) decreased Xpnpep2 during postnatal follicle development; and 4) increased colocalization of Xpnpep2 with Col3 and Col4. We also found that Xpnpep2 inversely regulated the expression of Col1, Col3, and Col4 in all the developmental stages studied. Thus, CrVI advanced GCN breakdown and increased follicle atresia in F1 female progeny by targeting Xpnpep2.

Intrauterine coadministration of ERK1/2 inhibitor U0126 inhibits interferon TAU action in the endometrium and restores luteolytic PGF2alpha pulses in sheep

In ruminants, prostaglandin F2 alpha (PGF2alpha) is synthesized and released in a pulsatile pattern from the endometrial luminal epithelial (LE) cells during the process of luteolysis. Interferon tau (IFNT) is a Type 1 IFN secreted by the trophoblast cells of the developing conceptus. IFNT acts locally on endometrial LE cells to inhibit pulsatile releases of PGF2alpha and thus establish an endocrine environment for recognition of pregnancy. Cell signaling pathways through which IFNT stimulates expression of multiple genes or proteins in endometrial LE are largely unknown. Results of the present investigation indicate that intrauterine administration of IFNT inhibits pulsatile release of PGF2alpha, while coadministration IFNT and ERK 1/2 inhibitor U0126 restores luteolytic PGF2alpha pulses in sheep. IFNT increases phosphorylation of ERK1/2 proteins and increases its interaction with PGT proteins in endometrial LE. Blockade of ERK1/2 pathways inhibits IFNT action, decreases pERK1/2 and PGT protein interactions, and re-establishes the spatial expression of the oxytocin receptor protein completely and the estrogen receptor protein partially without modulating the expression of interferon regulatory factor-2 (IRF-2) protein in endometrial LE. IFNT does not decrease expression of COX-2, PGDH, or PGT protein in endometrial LE. Our results provide important new insights into IFNT signaling and the molecular endocrine control of PGF2alpha release at the time of establishment of pregnancy in ruminants. This novel IFNT-ERK1/2 signaling module needs to be explored in future studies to understand molecular and cellular mechanisms of IFNT action in endometrial LE in ruminants.

Vessel generator noise as a settlement cue for marine biofouling species

Underwater noise is increasing globally, largely due to increased vessel numbers and international ocean trade. Vessels are also a major vector for translocation of non-indigenous marine species which can have serious implications for biosecurity. The possibility that underwater noise from fishing vessels may promote settlement of biofouling on hulls was investigated for the ascidian Ciona intestinalis. Spatial differences in biofouling appear to be correlated with spatial differences in the intensity and frequency of the noise emitted by the vessel's generator. This correlation was confirmed in laboratory experiments where C. intestinalis larvae showed significantly faster settlement and metamorphosis when exposed to the underwater noise produced by the vessel generator. Larval survival rates were also significantly higher in treatments exposed to vessel generator noise. Enhanced settlement attributable to vessel generator noise may indicate that vessels not only provide a suitable fouling substratum, but vessels running generators may be attracting larvae and enhancing their survival and growth.

Edaravone mitigates hexavalent chromium-induced oxidative stress and depletion of antioxidant enzymes while estrogen restores antioxidant enzymes in the rat ovary in F1 offspring

Environmental contamination of drinking water with chromium (Cr) has been increasing in more than 30 cities in the United States. Previous studies from our group have shown that Cr affects reproductive functions in female Sprague Dawley rats. Although it is impossible to completely remove Cr from the drinking water, it is imperative to develop effective intervention strategies to inhibit Cr-induced deleterious health effects. Edaravone (EDA), a potential inhibitor of free radicals, has been clinically used to treat cancer and cardiac ischemia. This study evaluated the efficacy of EDA against Cr-induced ovarian toxicity. Results showed that maternal exposure to CrVI in rats increased follicular atresia, decreased steroidogenesis, and delayed puberty in F1 offspring. CrVI increased oxidative stress and decreased antioxidant (AOX) enzyme levels in the ovary. CrVI increased follicle atresia by increased expression of cleaved caspase 3, and decreased expression of Bcl2 and Bcl2l1 in the ovary. EDA mitigated or inhibited the effects of CrVI on follicle atresia, pubertal onset, steroid hormone levels, and AOX enzyme activity, as well as the expression of Bcl2 and Bcl2l1 in the ovary. In a second study, CrVI treatment was withdrawn, and F1 rats were injected with estradiol (E₂) (10 μg in PBS/ethanol per 100 g body weight) for a period of 2 wk to evaluate whether E₂ treatment will restore Cr-induced depletion of AOX enzymes. E₂ restored CrVI-induced depletion of glutathione peroxidase 1, catalase, thioredoxin 2, and peroxiredoxin 3 in the ovary. This is the first study to demonstrate the protective effects of EDA against any toxicant in the ovary.

Persistent hexavalent chromium exposure impaired the pubertal development and ovarian histoarchitecture in wistar rat offspring

Hexavalent chromium (CrVI) is a highly toxic metal and a major environmental pollutant. Several studies indicate that CrVI exposure adversely affects reproductive function. We reported that maternal Cr exposure resulted in Cr accumulation in the reproductive organs of female offsprings. CrVI can cross the placental barrier and also can be passed through breastfeeding. The present investigation aimed to determine the persistent (in utero through puberal period) CrVI exposure-induced toxic effects on the reproductive functions of mother and the offspring. Induction of oxidative stress is one of the plausible mechanisms behind Cr-induced cellular deteriorations. Mother rats exposed to CrVI showed reduced reproductive outcome, while the offsprings showed higher accumulation of Cr in ovary, altered steroid, and peptide hormones. Specific activities of antioxidant enzymes were decreased and associated with increased levels of H2 O2 , and lipid peroxidation. CrVI exposure also damaged the ovarian histoarchitecture in various age groups studied. CrVI exposure also delayed the sexual maturation. Results from the present investigation suggest that CrVI exposure from in utero through puberal period significantly damaged the pubertal development through altered antioxidants, anemia, and altered hormone levels. These changes were associated with damaged ovarian histoarchitecture and extended estrous cycle in developing Wistar rats.

Postnatal exposure to chromium through mother's milk accelerates follicular atresia in F1 offspring through increased oxidative stress and depletion of antioxidant enzymes

Hexavalent chromium, CrVI, is a heavy metal endocrine disruptor, known as a mutagen, teratogen, and a group A carcinogen. Environmental contamination with CrVI, including drinking water, has been increasing in more than 30 cities in the United States. CrVI is rapidly converted to CrIII intracellularly, and CrIII can cause DNA strand breaks and cancer or apoptosis through different mechanisms. Our previous study demonstrated that lactational exposure to chromium results in a delay or arrest in follicle development and a decrease in steroid hormone levels in F1 female rats, both of which are mitigated (partial inhibition) by vitamin C. The current study tested the hypothesis that lactational exposure to CrIII accelerates follicle atresia in F1 offspring by increasing reactive oxygen species (ROS) and decreasing cellular antioxidants. Results showed that lactational exposure to CrIII dose-dependently increased follicular atresia and decreased steroidogenesis in postnatal day 25, 45, and 65 rats. Vitamin C mitigated or inhibited the effects of CrIII at all doses. CrIII increased hydrogen peroxide and lipid hydroperoxide in plasma and ovary; decreased the antioxidant enzymes (AOXs) GPx1, GR, SOD, and catalase; and increased glutathione S-transferase in plasma and ovary. To understand the effects of CrVI on ROS and AOXs in granulosa (GC) and theca (TC) cell compartments in the ovary, ROS levels and mRNA expression of cytosolic and mitochondrial AOXs, such as SOD1, SOD2, catalase, GLRX1, GSTM1, GSTM2, GSTA4, GR, TXN1, TXN2, TXNRD2, and PRDX3, were studied in GCs and TCs and in a spontaneously immortalized granulosa cell line (SIGC). Overall, CrVI downregulated each of the AOXs; and vitamin C mitigated the effects of CrVI on these enzymes in GCs and SIGCs, but failed to mitigate CrVI effects on GSTM1, GSTM2, TXN1, and TXN2 in TCs. Thus, these data for the first time reveal that lactational exposure to CrIII accelerated follicular atresia and decreased steroidogenesis in F1 female offspring by altering the ratio of ROS and AOXs in the ovary. Vitamin C is able to protect the ovary from CrIII-induced oxidative stress and follicle atresia through protective effects on GCs rather than TCs.

Androgen receptor expression in human thyroid cancer tissues: a potential mechanism underlying the gender bias in the incidence of thyroid cancers

Gender bias in the incidence of thyroid cancer is well known, however, the underlying mechanism is largely unknown. The current study determines variations in the molecular characteristics of thyroid cancers between men and women. Normal and cancerous thyroid tissues were collected from a total of 125 men and women who underwent surgical thyroidectomy. Testosterone levels in serum and thyroid cancer tissues were elevated in women while it decreased in men compared to respective control groups; whereas, ligand binding activity increased in men and decreased in women. Androgen receptor (AR) mRNA expression increased in a majority of men while it decreased in a majority of women except those with follicular thyroid carcinoma (FTC). In thyroid cancers of women, Pearson's correlation analysis showed a positive correlation of AR mRNA with AR protein, CBP and Sp1, whereas AR mRNA showed a negative correlation with p53. In case of men, AR mRNA showed a positive correlation with AR and cyclin D1 proteins in papillary thyroid carcinoma (PTC); and CBP and Sp1 in follicular thyroid adenoma (FTA), whereas AR mRNA showed a positive correlation with p53. Our study identified for the first time that AR is posttranscriptionally regulated by miR-124a in thyroid cancer tissues. Further, our in vitro studies with a PTC cell line (NPA-87-1) showed miR-124a as the potent inhibitor of AR that impairs cell proliferation even in the presence of testosterone. Thus, the current study suggests that: (i) the varying pattern of testosterone level and AR status in thyroid tissues of men and women may predispose to the gender specific incidence of thyroid tumors and (ii) miR-124a plays a significant role in determining the AR gene expression pattern and thus, androgen mediated thyroid tumor growth.

Early pregnancy induced expression of prostaglandin E2 receptors EP2 and EP4 in the ovine endometrium and regulated by interferon tau through multiple cell signaling pathways

Prostaglandin E2 (PGE(2)) plays pleiotropic roles at fetal-maternal interface during establishment of pregnancy. The objectives of the study were to: (i) determine regulation of PGE2 receptors EP1, EP2, EP3, and EP4 in the endometrium during the estrous cycle and early pregnancy; and (ii) understand endometrial epithelial and stromal cell-specific hormonal regulation of EP2 and EP4 in sheep. Results indicate that: (i) early pregnancy induces expression of EP2 and EP4 but not EP1 and EP3 proteins in the endometrium on days 12-16 compared to that of estrous cycle; (ii) intrauterine infusion of interferon tau (IFNT) increases expression of EP2 and EP4 proteins in endometrium; and (iii) IFNT activates distinct epithelial and stromal cell-specific JAK, EGFR, ERK1/2, AKT, or JNK signaling module to regulate expression of EP2 and EP4 proteins in the ovine endometrium. Our results indicate a role for EP2 and EP4-mediated PGE(2) signaling in endometrial functions and establishment of pregnancy in ruminants.

Induction of settlement in mussel (Perna canaliculus) larvae by vessel noise

Underwater sound plays an important role in the settlement behaviour of many coastal organisms. Large steel-hulled vessels are known to be a major source of underwater sound in the marine environment. The possibility that underwater sound from vessels may promote biofouling of hulls through triggering natural larval settlement cues was investigated for the mussel, Perna canaliculus. The mussel larvae showed significantly faster settlement when exposed to the underwater noise produced by a 125-m long steel-hulled passenger and freight ferry. Median time to attachment on the substrata (ie settlement) was reduced by 22% and the time taken for all experimental larvae to settle was reduced by 40% relative to a silent control. There was no difference in the survival of the mussel larvae among the various noise treatments. The decrease in settlement time of the mussel larvae appeared to correlate with the intensity of the vessel sound, suggesting that underwater sound emanating from vessels may be an important factor in exacerbating hull fouling by mussels.

RETRACTED: Ameliorative effect of vitamin C on hexavalent chromium-induced delay in sexual maturation and oxidative stress in developing Wistar rat ovary and uterus

At the request of the Editor and the Publisher, the following article:

Samuel JB, Stanley JA, Vengatesh G, Princess RA, Muthusami S, Roopha DP, Suthagar E, Kumar KM, Sebastian MS, Aruldhas MM. (2012) Ameliorative effect of vitamin C on hexavalent chromium-induced delay in sexual maturation and oxidative stress in developing Wistar rat ovary and uterus, Toxicology and Industrial Health 28(8): 720-733. DOI: 10.1177/0748233711422728

http://tih.sagepub.com/content/28/8/720.abstract

has been retracted from Toxicology and Industrial Health due to redundant publication by the same group of authors in another journal:

Samuel JB, Stanley JA, Roopha DP, Vengatesh G, Anbalagan J, Banu SK, Aruldhas MM. (2011) Lactational hexavalent chromium exposure-induced oxidative stress in rat uterus is associated with delayed puberty and impaired gonadotropin levels, Human & Experimental Toxicology 30(2):91-101. DOI: 10.1177/0960327110364638

http://het.sagepub.com/content/30/2/91.abstract

The two papers have used the same data and reporting with the Toxicology and Industrial Health manuscript inserting Vitamin C to differ the reporting. Additionally, the Toxicology and Industrial Health manuscript does not provide citations to original work by another author.

Chromium-VI arrests cell cycle and decreases granulosa cell proliferation by down-regulating cyclin-dependent kinases (CDK) and cyclins and up-regulating CDK-inhibitors

Environmental contamination with hexavalent chromium (CrVI) has been increasing in the drinking water of the USA and developing countries. CrVI causes various health problems including menstrual disorders and infertility. Recently, we reported that CrVI causes granulosa cell apoptosis through the intrinsic apoptotic pathway. Our previous studies showed that postnatal exposure to CrVI arrests follicle development. In order to explore the underlying mechanism, primary and immortalized granulosa cells from rats were treated with 10 μM potassium dichromate and analyses of the cell cycle, and cell cycle regulatory proteins were performed. CrVI decreased cell proliferation as a result of cell cycle arrest and down-regulated cyclin-dependent kinases (CDK), cyclins, and PCNA while up-regulating CDK-inhibitors and down-regulating FSH receptor and ERβ. Vitamin C mitigated the effects of CrVI. This study shows that CrVI causes cell cycle arrest in granulosa cells by altering cell cycle regulatory proteins with potential intervention by vitamin C.

Hexavalent chromium-induced apoptosis of granulosa cells involves selective sub-cellular translocation of Bcl-2 members, ERK1/2 and p53

Hexavalent chromium (CrVI) has been widely used in industries throughout the world. Increased usage of CrVI and atmospheric emission of CrVI from catalytic converters of automobiles, and its improper disposal causes various health hazards including female infertility. Recently we have reported that lactational exposure to CrVI induced a delay/arrest in follicular development at the secondary follicular stage. In order to investigate the underlying mechanism, primary cultures of rat granulosa cells were treated with 10 μM potassium dichromate (CrVI) for 12 and 24h, with or without vitamin C pre-treatment for 24h. The effects of CrVI on intrinsic apoptotic pathway(s) were investigated. Our data indicated that CrVI: (i) induced DNA fragmentation and increased apoptosis, (ii) increased cytochrome c release from the mitochondria to cytosol, (iii) downregulated anti-apoptotic Bcl-2, Bcl-XL, HSP70 and HSP90; upregulated pro-apoptotic BAX and BAD, (iv) altered translocation of Bcl-2, Bcl-XL, BAX, BAD, HSP70 and HSP90 to the mitochondria, (v) upregulated p-ERK and p-JNK, and selectively translocated p-ERK to the mitochondria and nucleus, (vi) activated caspase-3 and PARP, and (vii) increased phosphorylation of p53 at ser-6, ser-9, ser-15, ser-20, ser-37, ser-46 and ser-392, increased p53 transcriptional activation, and downregulated MDM-2. Vitamin C pre-treatment mitigated CrVI effects on apoptosis and related pathways. Our study, for the first time provides a clear insight into the effect of CrVI on multiple pathways that lead to apoptosis of granulosa cells which could be mitigated by vitamin C.

Is gender difference in postnatal thyroid growth associated with specific expression patterns of androgen and estrogen receptors?

Variations in sex steroids bioavailability were linked to the gender difference in the growth of thyroid glands of neonatal rats. In the present study we tested androgen receptor (AR) and estrogen receptor (ER) concentrations by ligand binding assay, and expression of their genes by RT-PCR and Western blot in the thyroid glands of neonatal rats. AR concentration remained elevated from postnatal day (PND) 10 onwards in males, whereas it decreased by PND 20 in females. AR mRNA and protein expressions were higher in males than females, which increased by PND 10, decreased after PND 15 and reached the nadir by PND 20. ER concentration increased by PND 10 and decreased thereafter in both sex. ERα mRNA expression diminished by PND 15 in both sex; while ERβ mRNA decreased by PND 15 to reach the nadir by PND 20 in males, it was augmented by PND 10 in females to reach the peak by PND 15 and diminished by PND 20. ERα protein expression increased by PND 10 and remained elevated till PND 20 in both sex. ERβ protein expression in males increased by PND 10 and decreased by PND 20, while it remained static up to PND 15 and decreased in females. Testosterone stimulated [(3)H]-thymidine uptake and the expression of IGF-1 and NIS genes in thyrocytes of both sex in vitro, while estradiol stimulated them in females but not in males. We conclude that androgens influence the growth and differentiation of thyrocytes through augmented expression of AR, IGF-1 and NIS in either sex, whereas estrogen imparts the gender difference, which may be at a level beyond the expression of ERs.

Lactational hexavalent chromium exposure-induced oxidative stress in rat uterus is associated with delayed puberty and impaired gonadotropin levels

Hexavalent chromium (CrVI) is a transition element utilized in many fields of modern industries. CrVI is a reproductive metal toxicant that can traverse the placental barrier and cause a wide range of fetal effects. Therefore, the present study was carried out to determine the CrVI-induced utero-toxicity. In the present study, lactating rats received drinking water containing CrVI (50 mg/L and 200 mg/L) from postnatal days (PND) 1-21. During PND 1-21, the pups received CrVI via the mother's milk. Pups from both control and treatment groups were continued on regular diet and water from PND-21 onwards and euthanized on PND-45 and -65. Specific activities antioxidants such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione-S-transferase (GST) were estimated. Hydrogen peroxide (H₂O₂), lipid peroxidation (LPO) and serum gonadotropins viz. Luteinizing hormone (LH) and follicle stimulating hormone (FSH) were also assayed. Specific activities of SOD, CAT, GPX, GR and GST and serum testosterone and progesterone were significantly decreased, while H₂O₂, LPO and serum FSH was increased in 50-parts per million (ppm) and 200 ppm-treated rats in an age-dependent manner. These results suggest that lactational CrVI exposure induces oxidative stress in rat uterus by decreasing antioxidant enzymes, which were associated with delayed puberty and altered steroids and gonadotrophin levels.

Hydration study of homopolypeptides by (2)H NMR

Deuteron T(1) and T(2) was studied as a function of hydration in homopolyglycine (PG) and homopolyproline (PP). Water deuteron relaxation rates in PG conform to a hydration model involving two types of primary hydration sites where water is directly bonded to the polymer. Once these sites are filled, additional water only bonds to water molecules at the primary sites and in so doing affect their dynamics. PP exhibits an anomalous T(1) and T(2) hydration dependence which has been interpreted in terms of a cooperative water molecule-PP molecule helical conformational rearrangement which occurs once a certain hydration level is reached. The proposal of a water-PP structure is tested using molecular dynamics simulations.

Prefrontal membrane phospholipid metabolism of child and adolescent offspring at risk for schizophrenia or schizoaffective disorder: an in vivo 31P MRS study

In vivo (31)P magnetic resonance spectroscopy ((31)P MRS) studies have shown abnormal membrane phospholipid metabolism in the prefrontal cortex (PF) in the early course of schizophrenia. It is unclear, however, whether these alterations also represent premorbid risk indicators in schizophrenia. In this paper, we report in vivo (31)P MRS data on children and adolescents at high risk (HR) for schizophrenia. In vivo (31)P MRS studies of the PF were conducted on 16 nonpsychotic HR offspring of parents with schizophrenia or schizoaffective disorder, and 37 age-matched healthy comparison (HC) subjects. While 11 of the HR subjects had evidence of Axis I psychopathology (HR-P), five HR subjects had none (HR-NP). We quantified the freely mobile phosphomonoester (PME) and phosphodiester (PDE) levels reflecting membrane phospholipid precursors and breakdown products, respectively, and the relatively broad signal underlying PDE and PME peaks, comprised of less mobile molecules with PDE and PME moieties (eg, synaptic vesicles and phosphorylated proteins). Compared to HC subjects, HR subjects had reductions in freely mobile PME; the differences were accounted for mainly by the HR-P subjects. Additionally, HR-P subjects showed increases in the broad signal underlying the PME and PDE peaks in the PF. To conclude, these data demonstrate new evidence for decreased synthesis of membrane phospholipids and possibly altered content or the molecular environment of synaptic vesicles and/or phosphoproteins in the PF of young offspring at risk for schizophrenia. Follow-up studies are needed to examine the predictive value of these measures for future emergence of schizophrenia in at-risk individuals.

Postprocessing method to segregate and quantify the broad components underlying the phosphodiester spectral region of in vivo (31)P brain spectra

In a typical, in vivo (31)P brain spectrum, the phosphomonoester (PME) and phosphodiester (PDE) spectral region not only contains signals from freely mobile PMEs and PDEs (which are anabolic and catabolic products of membrane phospholipids) but also signals of broader underlying lineshapes from less-mobile molecules. In general, either the PME and PDE resonances are quantified as a combined value of freely mobile metabolites plus less-mobile molecules or the broader underlying signal is reduced/eliminated prior to or post data collection. In this study, a postprocessing method that segregates and quantifies the individual contributions of the freely mobile metabolites and the less-mobile molecules is introduced. To demonstrate the precision and accuracy of the method, simulated data and in vivo (31)P brain spectroscopy data of healthy individuals were quantified. The ability to segregate and quantify these various PME and PDE contributions provides additional spectral information and improves the accuracy of the interpretation of (31)P spectroscopy results. Magn Reson Med 45:390-396, 2001.

Molecular insights into neurodevelopmental and neurodegenerative diseases

Magnetic resonance spectroscopy (MRS) is a non-invasive physical technique that is routinely used to determine the quantity and structure of organic molecules in solution. Technical advances that have expanded the usefulness of this technique include: (1) high resolution MRS to identify and quantify individual molecules present in complex mixtures of tissue extracts; (2) in vivo MRS techniques to non-invasively monitor metabolites in humans; (3) structure determination of proteins of moderate size; and (4) improved structure characterization of solids and liquid crystals, such as the detection of phase changes in membranes. The focus of this review is on the first two technical advances mentioned above. The strengths of MRS as a research tool to investigate molecular alterations in disease states include ease of sample preparation, minimum sample manipulation, avoidance of the preparation of derivatives, and the ability to analyze an unfractionated sample. The strengths of MRS in the clinic are its ability to measure neuronal metabolite levels non-invasively in humans and its potential for disease diagnosis, monitoring disease progression, and assessing the efficacy of experimental therapies.

Magnetic resonance spectroscopy in schizophrenia: methodological issues and findings--part II

Magnetic resonance spectroscopy allows investigation of in vivo neurochemical pathology of schizophrenia. "First generation" studies, focusing on phosphorus and proton magnetic resonance spectroscopy, have suggested alterations in membrane phospholipid metabolism and reductions in N-acetyl aspartate in the frontal and temporal lobes. Some discrepancies remain in the literature, perhaps related to the variations in medication status and phase of illness in the patients examined, as well as in magnetic resonance spectroscopy methodology; the pathophysiologic significance of the findings also remains unclear. Technologic advances in magnetic resonance spectroscopy in recent years have expanded the potential to measure several other metabolites of interest such as the neurotransmitters glutamate and gamma-aminobutyric acid and macromolecules such as membrane phospholipids and synaptic proteins. Issues of sensitivity, specificity, measurement reliability, and functional significance of the magnetic resonance spectroscopy findings need to be further clarified. The noninvasive nature of magnetic resonance spectroscopy allows longitudinal studies of schizophrenia both in its different phases and among individuals at genetic risk for this illness. Future studies also need to address confounds of prior treatment and illness chronicity, take advantage of current pathophysiologic models of schizophrenia, and be hypothesis driven.

Magnetic resonance spectroscopy in schizophrenia: methodological issues and findings--part I

Our knowledge of the biological basis of schizophrenia has significantly increased with the contribution of in vivo proton and phosphorus magnetic resonance spectroscopy (MRS), a noninvasive tool that can assess the biochemistry from a localized region in the human body. Studies thus far suggest altered membrane phospholipid metabolism at the early stage of illness and reduced N-acetylaspartate, a measure of neuronal volume/viability in chronic schizophrenia. Inconsistencies remain in the literature, in part due to the complexities in the MRS methodology. These complexities of in vivo spectroscopy make it important to understand the issues surrounding the design of spectroscopy protocols to best address hypotheses of interest. This review addresses these issues, including 1) understanding biochemistry and the physiologic significance of metabolites; 2) the influence of acquisition parameters combined with spin-spin and spin-lattice relaxation effects on the MRS signal; 3) the composition of spectral peaks and the degree of overlapping peaks, including the broader underlying peaks; 4) factors affecting the signal-to-noise ratio; 5) the various types of localization schemes; and 6) the objectives to produce accurate and reproducible quantification results. The ability to fully exploit the potentials of in vivo spectroscopy should lead to a protocol best optimized to address the hypotheses of interest.

Metabolic alterations in postmortem Alzheimer's disease brain are exaggerated by Apo-E4

Alterations in phospholipid metabolites are a characteristic abnormality of Alzheimer's disease (AD). Many of these alterations have been demonstrated by magnetic resonance spectroscopy (MRS) studies of postmortem tissue. Phosphodiesters appear to be elevated late in the disease and phosphomonoesters appear to be elevated early in the disease and then decrease. Second to aging, the most robust risk factor for AD identified to date is the presence of the E4 allele of apolipoprotein-E (Apo-E). Because apolipoproteins are intimately involved in lipid metabolism, this study was performed to determine if the presence of the Apo-E4 allele affects the abnormalities in phospholipid metabolites in AD brain. Perchloric acid extracts from 12 Apo-E 3/3, 31 3/4, 6 4/4 AD brains and 5 Apo-E 3/3 control brains were studied by both proton magnetic resonance spectroscopy and phosphorus-31 magnetic resonance spectroscopy. When the E4-positive AD samples were compared with the 3/3 AD samples, an exaggeration in both phosphomonoester and phosphodiester abnormalities was observed. The decrease in N-acetyl-L-aspartate (NAA) was also exaggerated. These results suggest membrane phospholipid metabolite alterations observed in AD are more severe in the presence of the Apo-E4 allele.

Proton magnetic resonance spectroscopic imaging in patients with extratemporal epilepsy

PURPOSE

Reduced levels of N-acetylaspartate (NAA) in temporal lobes responsible for temporal lobe epilepsy have been observed consistently in proton magnetic resonance spectroscopy (MRS) studies.

METHODS

We investigated the potential of proton MRS to detect low NAA outside of the temporal lobes in patients with non-lesional partial extratemporal epilepsy. Proton MR spectroscopic imaging (MRSI) data of both frontal lobes and central/postcentral regions were obtained in 20 such patients and 16 normal control subjects. The epileptogenic region was determined by an extensive clinical-EEG investigation, including the recording of habitual seizures in each patient, and intracranial EEG recordings in 10 patients.

RESULTS

The relative NAA resonance intensities (i.e., NAA/phosphocreatine plus creatine (CR(t)), NAA/choline-containing metabolites (Cho(t)) and NAA/Cr(t) + Cho(t)), were all significantly reduced throughout the spectroscopic image as compared with that of the controls. Furthermore, reduction of the NAA ratios was greater in the epileptogenic region as compared with the nonepileptogenic regions, on EEG investigation.

CONCLUSIONS

In vivo proton MRSI of patients with nonlesional partial extratemporal epilepsy detected evidence of widespread neuronal damage or dysfunction that was greatest in the region of seizure focus.

Magnetic resonance spectroscopic changes in Alzheimer's disease

In vitro and in vivo 31P magnetic resonance (MR) spectroscopy studies of Alzheimer's disease (AD) brain have revealed alterations in membrane phospholipid metabolism and high-energy phosphate metabolism. Mildly demented AD patients compared with control subjects have increased levels of phosphomonoesters, decreased levels of phosphocreatine and probably adenosine diphosphate and an increased oxidative metabolic rate. As the dementia worsens, levels of phosphomonoesters decrease and levels of phosphocreatine and adenosine di-phosphate increase. The changes in oxidative metabolic rate suggest that the AD brain is under energetic stress. The phosphomonoester findings support our in vitro findings and implicate basic defects in membrane metabolism in AD brain. MR spectroscopy provides new diagnostic insights and a noninvasive method to follow the progression of the disease and the metabolic response to therapeutic interventions.

Aggregation of beta-amyloid peptide is promoted by membrane phospholipid metabolites elevated in Alzheimer's disease brain

Increased amounts of beta-amyloid (A beta) peptide deposits are found in Alzheimer's disease brain. These amyloid deposits have been implicated in the pathophysiology of this common dementing illness. A beta peptides have been shown to be toxic to neurons in cell culture, and this toxicity is critically dependent on the aggregation of the peptide into cross-beta-pleated sheet fibrils. Also, in vivo and postmortem NMR studies have shown changes in certain brain membrane phospholipid metabolites in normal aging and more extensive alterations in patients with Alzheimer's disease. The finding that membrane phospholipids affect the aggregation of A beta suggests that the abnormalities in membrane metabolism found in Alzheimer's disease could affect the deposition of A beta in vivo. Therefore, we examined the effect of membrane phospholipid metabolites that are altered in Alzheimer's disease brain on the aggregation of A beta(1-40) using a light scattering method. Certain metabolites (glycerophosphocholine, glycerophosphoethanolamine, and alpha-glycerophosphate) augment the aggregation of A beta. Other membrane phospholipid metabolites (phosphocholine, phosphoethanolamine, and inositol-1-phosphate) have no effect. We conclude that increased membrane phospholipid metabolite concentrations may play a role in the deposition of A beta seen in normal aging and the even greater deposition of A beta observed in Alzheimer's disease.

Magnetic resonance imaging volumetric and phosphorus 31 magnetic resonance spectroscopy measurements in schizophrenia

The purpose of this study was to examine the relationship between phosphorus magnetic resonance spectroscopy (31P MRS) parameters and left prefrontal volumes in both patients with schizophrenia and healthy subjects. 31P MRS parameters and magnetic resonance imaging (MRI) volumetric data were collected in the left prefrontal region in 10 patients with schizophrenia and 10 healthy subjects of comparable age, handedness, sex, educational level, and parental educational level. No correlations were found between any MRS parameter and grey matter volumes in the combined subjects. Phosphomonoester (PME) and grey matter volumes, however, were both correlated negatively with age. PMEs were found to be decreased, and calculated intracellular magnesium ([Mg2+]intra) was found to be increased in the patients with schizophrenia compared with healthy subjects after adjusting for left prefrontal grey and white matter, total brain volume, and age. These findings suggest that cortical grey and white manner volumes are not directly related to PME and [Mg2+]intra abnormalities in schizophrenia patients.

Proton magnetic resonance spectroscopic imaging for discrimination of absence and complex partial seizures

We performed proton magnetic resonance spectroscopic imaging of the temporal lobes between, during, and soon after nonconvulsive seizures in 20 patients with documented temporal lobe epilepsy, 5 patients with primary generalized epilepsy, and 2 patients with secondary generalized epilepsy. Our objective was to determine whether there were metabolic changes observable by magnetic resonance spectroscopic imaging during seizures and whether these changes were specific for focal or generalized nonconvulsive seizures. We found a significant increase in lactate to creatine plus phosphocreatine (lactate/creatine) values, reflecting an imbalance in energy supply and demand or an adaptation in response to ictal neuronal discharges, during and soon after complex partial seizures, but not during or soon after absence seizures associated with generalized epilepsy. In patients with temporal lobe epilepsy, the N-acetylaspartate resonance relative to creatine plus phosphocreatine was low in one or both temporal lobes, indicating neuronal loss or damage. This was not observed in patients with primary generalized epilepsy. The regions with abnormal lactate/creatine and N-acetylaspartate/creatine values corresponded to the epileptogenic focus as defined by clinical-electroencephalographic investigation. There was no change in the N-acetylaspartate/creatine values in the temporal lobes between the interictal, ictal, or postictal states. We conclude that (1) partial seizures are associated with abnormally high lactate levels, but absence seizures are not, and (2) no short-term changes of N-acetylaspartate occur during or soon after complex partial seizures or absence seizures. These findings may be related to the lack of postictal confusion in patients with absence seizures, as well as with the more benign course of primary generalized epilepsy with nonconvulsive attacks.

An in vivo proton magnetic resonance spectroscopy study of schizophrenia patients

The level of the 1H metabolites in the left dorsolateral prefrontal region of schizophrenia patients at different stages of illness were measured in vivo using a short echo time spectroscopy technique. During both the early onset and chronic stages, normal N-acetylaspartate levels were observed, which suggests that these patients had no significant neuronal cell damage and/or loss. The in vivo measurements of glutamate in the first-episode, drugnaive patients failed to provide convincing evidence for the involvement of the glutamatergic system in the dorsolateral prefrontal region. Significant differences in the glutamine levels were observed in the acutely medicated and chronic patients; however, the interpretation of these differences requires further study.