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Highlights: [•] Leaning disorder [•] Heavy metals [•] United Arab Emirates [•] Environmental exposure [•] Children [Copyright &y& Elsevier]

ABSTRACT There is an increasing belief that organophosphorus compounds (OPCs) impair glucose homeostasis and cause hyperglycemia and diabetes mellitus. The present study was undertaken to investigate the putative diabetogenic effect of sub-lethal and sub-chronic exposure to paraoxon (POX), an extremely hazardous OPC used in pesticides. The effect of paraoxon on streptozotocin-induced diabetic rats was also examined. Each rat was injected with 100 nmol of POX 5 days per week for 6 weeks. Blood glucose levels and red blood cell acetylcholinesterase activity were measured weekly. Biochemical analysis and morphological studies were performed at the end of the experiment. The results revealed that POX neither induces nor exacerbates diabetes mellitus in experimental rats. Liver and kidney/body weight ratios revealed statistically insignificant differences when compared with controls. Biochemical analysis of urine samples showed a small but not significant increase in protein level in all groups. Urine bilirubin was significantly higher in the diabetes + POX group when compared with the control group. The number of blood cells in urine was significantly higher in the POX-treated group compared with the control group. Hyperglycemia was noted in the diabetes and diabetes + POX groups, but neither in the saline control nor in POX-treated normal rats. Electron microscopy of POX-treated pancreas did not show any morphological changes in beta cells. These results suggest that POX does not cause diabetes mellitus at sub-lethal sub-chronic exposure. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Phytochemical compounds are emerging as a new generation of anticancer agents with limited toxicity in cancer patients. The purpose of this study was to investigate the potential impact of thymoquinone ( TQ), the major constituent of black seed, on survival, invasion of cancer cells in vitro, and tumor growth in vivo. Exposure of cells derived from lung ( LNM35), liver (HepG2), colon ( HT29), melanoma ( MDA- MB-435), and breast ( MDA- MB-231 and MCF-7) tumors to increasing TQ concentrations resulted in a significant inhibition of viability through the inhibition of Akt phosphorylation leading to DNA damage and activation of the mitochondrial-signaling proapoptotic pathway. We provide evidence that TQ at non-toxic concentrations inhibited the invasive potential of LNM35, MDA- MB-231, and MDA- MB231-1833 cancer cells. Moreover, we demonstrate that TQ synergizes with DNA-damaging agent cisplatin to inhibit cellular viability. The anticancer activity of thymoquinone was also investigated in athymic mice inoculated with the LNM35 lung cells. Administration of TQ (10 mg/kg/i.p.) for 18 days inhibited the LNM35 tumor growth by 39% ( P < 0.05). Tumor growth inhibition was associated with significant increase in the activated caspase-3. The in silico target identification suggests several potential targets of TQ mainly HDAC2 proteins and the 15-hydroxyprostaglandin dehydrogenase. In this context, we demonstrated that TQ treatment resulted in a significant inhibition of HDAC2 proteins. In view of the available experimental findings, we contend that thymoquinone and/or its analogues may have clinical potential as an anticancer agent alone or in combination with chemotherapeutic drugs such as cisplatin. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effects of melatonin on low-grade inflammation and oxidative stress in young male Zucker diabetic fatty (ZDF) rats, an experimental model of metabolic syndrome and type 2 diabetes mellitus (T2DM). ZDF rats (n = 30) and lean littermates (ZL) (n = 30) were used. At 6 wk of age, both lean and fatty animals were subdivided into three groups, each composed of 10 rats: naive (N), vehicle treated (V), and melatonin treated (M) (10 mg/kg/day) for 6 wk. Vehicle and melatonin were added to the drinking water. Pro-inflammatory state was evaluated by plasma levels of interleukin-6 (IL-6), tumor necrosis factor-a (TNF-a), and C-reactive protein (CRP). Also, oxidative stress was assessed by plasma lipid peroxidation (LPO), both basal and after Fe2+/H2O2 inducement. ZDF rats exhibited higher levels of IL-6 (112.4 ± 1.5 pg/mL), TNF-a (11.0 ± 0.1 pg/mL) and CRP (828 ± 16.0 µg/mL) compared with lean rats (IL-6, 89.9 ± 1.0, P < 0.01; TNF-a, 9.7 ± 0.4, P < 0.01; CRP, 508 ± 21.5, P < 0.001). Melatonin lowered IL-6 (10%, P < 0.05), TNF-a (10%, P < 0.05), and CRP (21%, P < 0.01). Basal and Fe2+/H2O2-induced LPO, expressed as malondialdehyde equivalents (µmol/L), were higher in ZDF rats (basal, 3.2 ± 0.1 versus 2.5 ± 0.1 in ZL, P < 0.01; Fe2+/H2O2-induced, 8.7 ± 0.2 versus 5.5 ± 0.3 in ZL; P < 0.001). Melatonin improved basal LPO (15%, P < 0.05) in ZDF rats, and Fe2+/H2O2- induced LPO in both ZL (15.2%, P < 0.01) and ZDF rats (39%, P < 0.001). These results demonstrated that oral melatonin administration ameliorates the pro-inflammatory state and oxidative stress, which underlie the development of insulin resistance and their consequences, metabolic syndrome, diabetes, and cardiovascular disease. [ABSTRACT FROM AUTHOR]

In this study, target compounds 5-12 were synthesized via acid amine coupling of ibuprofen and naproxen with methyl ester derivatives of amino acids, namely, l-proline, sarcosine, l-tyrosine, and l-glutamic acid. When tested for anti-inflammatory activity using the acute carrageenan-induced hind paw method in rats, compounds 5-12 showed significantly greater anti-inflammatory activity, in the range of 40.64%-87.82%, compared with a placebo control group (P , 0.001). Among the newly synthesized compounds 5-12, naproxen derivatives 9-12 with anti-inflammatory activity ranging between 66.99% and 87.82% showed significantly higher (P < 0.05) potency than ibuprofen derivatives 5-5-8 with inhibition in the range of 22.03%-52.91% and control groups of ibuprofen (76.34%) or naproxen (75.59%, P < 0.05). Moreover, derivatives 9-12 derived from naproxen, in particular compounds 9 and 10 which achieved 83.91% and 87.82% inhibition of inflammation, respectively, showed significantly (P < 0.05) higher potency than naproxen derivatives 11 and 12. Notably, among naproxen derivatives 9-12, the gastric ulcerogenicity for 9 (ulcer index 11.73) and 10 (ulcer index 12.30) was found to be significantly lower (P < 0.05) than that of the active ibuprofen and naproxen control groups with ulcer indices of 22.87 and 24.13, respectively. On the other hand, naproxen derivatives 9-11 showed significant inhibition (P < 0.05) of prostaglandin E2 synthesis when compared with the active control group receiving indomethacin, suggesting a correlation between the observed low ulcerogenicity and effect on prostaglandin E2 synthesis for compounds 9 and 10. However, significant inhibition of prostaglandin E2 observed for naproxen derivative 11 (107.51) did not correlate with its observed ulcer index (16.84). Our overall findings for carbamoylmethyl ester derivatives named 5-12 clearly suggest that the compounds showing potent antiinflammatory effect. [ABSTRACT FROM AUTHOR]

In the present study, the effect of 20 days of dehydration in the presence or absence of losartan (angiotensin II AT1 receptor antagonist) on insulin-like growth factor-1(IGF-1) and insulin-like growth factor-binding protein-3(IGFBP-3) in plasma of the one-humped camel was studied. Eighteen male camels, 3-4 years of age, were divided into three equal groups: control, dehydrated, and dehydrated-losartan-treated groups. The control camels were given food and water ad libitum. The two dehydrated groups underwent 20 days of water deprivation but were given food ad libitum. The dehydrated-losartan-treated camels were given losartan injection (Merck, USA), intravenously at a dose of 5 mg/kg body weight daily for 20 days. Our results demonstrated a progressive decrease in the circulating levels of IGF-1 and IGFBP-3 in the dehydrated and dehydrated-losartan-treated animals across dehydration compared to their basal levels and time-matched control. On day 5 of dehydration, the IGF-1 level in the losartan-treated group showed a decrease of 60 % and the dehydrated group showed 45 % decrease from their baseline levels and time-matched control. On day 10 the decrease in the losartan-treated animals reached 74 % and for the dehydrated was 62 %. On day 20 the decrease in the losartan-treated was 89 % and for the dehydrated reached 80 % from their baseline levels and time-matched control. Dehydration in the presence or absence of losartan caused a decrease in the circulating level of IGFBP-3. The decrement reached 26 % on day 10 and 20 for the treated camels, while the decrease for the dehydrated was 22 % on day 10 of dehydration and reached 29 % on day 20 compared to their baseline levels and time-matched control. In conclusion, dehydration alone, or in presence of Angiotensin II AT1 receptor blocker caused significant decrease in the circulating levels of IGF-1 and IGFBP-3 compared to their basal values and to time-matched controls. Losartan enhanced the effect of dehydration mainly in the early phase of dehydration for both parameters; albeit, no significant differences between the two dehydrated groups was observed. Finally, these findings suggest an essential role of IGF-1and IGFBP-3 in the dehydration state of these dromedarian camels. [ABSTRACT FROM AUTHOR]

No systematic studies have been carried out on the effects of toxic metals on childhood behavior in the Gulf Region including the UAE. The relationship between blood levels of heavy metals and Attention Deficit Hyperactivity disorder (ADHD) were explored in school-aged children of UAE and it was found that increased blood concentrations of lead (Pb), manganese (Mn) and zinc (Zn) were significantly associated with ADHD. The findings suggest that monitoring for exposure to heavy metal levels and education on potential child health hazards related to them are indicated. [ABSTRACT FROM PUBLISHER]

Various beneficial properties has been attributed to Nigella sativa, including its antioxidant potential. Previously, it was reported that supercritical fluid extraction (SFE) could be used to obtain N. sativaextract rich in antioxidants. In the present study, N. sativaextracts prepared using the previously optimized SFE as well as the traditional Soxhlet extraction approaches were analyzed for various known antioxidants. N. sativaextracts were found to prevent protein carbonyl formation as well as depletion of intracellular glutathione (GSH) in fibroblasts exposed to toluene. Furthermore, partially purified SFE and Soxhlet fractions could prevent loss of hepatic GSH in toluene-induced oxidative stressed Wistar rats as well as in L929 fibroblasts. The results showed that SFE-produced N. sativaextract is richer in antioxidants than the Soxhlet approach. It was also shown using preparative silica gel and reverse phase chromatography that different fractions of SFE-extracted or Soxhlet-extracted N. sativahad different levels of protective effects with regards to GSH depletion in vivo as well as in cell culture. Although fractions rich in thymoquinone were found to be most potent in terms of antioxidant capacity, the data indicates that the protective effects of N. sativamay not only be due to thymoquinone, but perhaps other antioxidants. [ABSTRACT FROM AUTHOR]

Gastric pathology is a common complication in diabetes mellitus. The aim of the study was to evaluate the functions and morphological changes of the parietal cells of the rat stomach after streptozotocin-induced diabetes. Diabetes mellitus was induced in Wistar rats by a single intraperitoneal injection of streptozotocin (60 mg/kg body weight). The rats were weighed weekly and sacrificed after 6 months. The glandular portion of the stomach was removed and processed for H+-K+-ATPase immunohistochemistry and light and electron microscopy studies. Acid secretion was measured in vivo. After 6 months of diabetes, the mean weight of the rats was significantly lower ( P < 0.001) compared to control. The mean weight of the stomach to body weight percentage increased significantly ( P < 0.001) compared to control. The blood glucose level in diabetic rats was significantly higher ( P < 0.001) than in normal control. Diabetic rats showed significant ( P < 0.001) decrease in basal and stimulated acid secretion when compared to control. Electron micrographs of the parietal cells of glandular stomach of diabetic rats revealed significant ( P < 0.0002) reduction in the number of mitochondria and a small though not significant increase in the number of canaliculi in the parietal cells compared with normal. Immunohistochemistry showed reduced H+-K+-ATPase ( P < 0.00001) compared to control. Long-term diabetes induces morphological as well as functional changes in gastric parietal cells. The decrease in the number of mitochondria accompanied by reduced in H+-K+-ATPase in parietal cells may explain the reduced acid secretion observed in diabetics. [ABSTRACT FROM AUTHOR]

Genetic alterations of the proto-oncogene human epidermal growth factor receptor (HER-2/neu) have been shown to induce malignant transformation and metastasis. Genotyping studies have addressed the association of codon 655 isoleucine to valine polymorphism located in the transmembrane coding region and the risk of breast cancer, but the results are inconsistent. In this study, we investigated the association of HER-2/neu Ile655Val polymorphism and the risk of breast cancer in a Sudanese population. In addition, the joint effects of HER-2/neu variants and our previously reported ESR1C325G polymorphism were tested for their association with breast cancer risk. Candidate single nucleotide polymorphism (SNP) in HER-2/neu Ile655Val [db SNP rs1136200] was genotyped in breast cancer patients and in healthy controls that were randomly selected from the same age group as the patients. Genotyping was performed using a high-throughput allelic discrimination method using real-time PCR, and data on clinical features and demographic details were collected. Associations between genotype and breast cancer were assessed by means of logistic regression. The prevalence of Val/Val genotype was similar in patients of breast cancer and control subjects. In comparison with the Ile/Ile genotype, the Ile/Val had a borderline significantly ( P= 0.06) higher risk of breast cancer (OR = 2.95, 95% CI: 0.97–8.96). Regarding the genotypic and allelic frequencies stratified by age and menopausal status, there were no significant associations. A significantly higher risk of breast cancer was observed among homozygous carriers of ESR1325 CC genotype and heterozygous carriers of HER-2/neu655 Ile/Val genotype ( P= 0.05; adjusted OR = 4.9, 95% CI: 1.0–24). The association of HER-2/neu Ile655Val polymorphism and the risk of breast cancer was borderline significant with the heterozygous carrier being at higher risk. However, the frequency of different polymorphic variants varies with ethnicity. The results of this study suggest that a significant gene–gene interaction between ESR1325C (previously reported) and HER-2/neu Ile655Val variants may jointly contribute to a higher risk of breast cancer. [ABSTRACT FROM AUTHOR]

Estrogen and estrogen receptors play important roles in the proliferation and development of breast cancer. Several genetic alterations identified in the estrogen receptor α gene (ESR1) are thought to influence the expression or function of this protein, and many have been evaluated for their role in breast cancer predisposition. The aim of this study was to evaluate the role of the C325G single nucleotide polymorphism (SNP) in the ESR1 in predisposition to breast cancer. The candidate SNP C325G in ESR1, exon 4 was genotyped in breast cancer patients and in healthy controls that were age and sex matched. Genotyping was performed using both single-stranded conformational polymorphism (SSCP) and a higher throughput allelic discrimination method using real-time PCR. Data on clinical features and demographic details were collected. Significant association of breast cancer risk was shown in the subgroup of women 50 years and younger who had the C allele (OR: 2.28, 95% CI: 1.10–4.72) ( P= 0.03). However, the overall susceptibility to breast cancer was not significant, although all estimates were in the direction of a higher risk in women with CC genotypes. This study found significant evidence that polymorphism within the low penetrance ESR1 is associated with breast cancer susceptibility in women of 50 years or younger. There is also an indication that G allele is protective (compared to C allele). [ABSTRACT FROM AUTHOR]

Background: Epidemiological evidence suggests that Alzheimer's disease (AD) and Type‐2 Diabetes Mellitus (T2DM) share pathophysiological processes. T2DM causes central insulin resistance, which generates a hypoglycemic microenvironment in the brain. The oxidative stress established as a result leads to mitochondrial dysfunction, inflammation, advanced glycation end‐product (AGE) production, insulin receptor signaling pathway impairment, and insulin‐degrading enzyme (IDE) inhibition. These widespread repercussions catalyze amyloid‐β (Aβ) plaque and neurofibrillary tangle (NFT) formation. Here, we hypothesize that T2DM is associated with an increased AD pathological burden in clinically‐ and pathologically‐diagnosed AD. Method: All data were obtained from the Uniform Data Set (UDS) v3, the Neuropathology Data Set, and the Researcher's Data Dictionary‐Genetic Data from the NIA funded National Alzheimer's Coordinating Center (NACC). The data was compiled by NACC in a dataset querying, the following keywords: "Alzheimer's disease", "Type 2 diabetes mellitus", "Thal phase (A score)", "Braak neurofibrillary stage (B score)", "Neuritic plaque score (C score)", and "Alzheimer's disease neuropathology change (ABC score)". The dataset relies on autopsy‐confirmed data in clinically‐diagnosed AD patients who were assessed for diabetes type in form A5 or D2 during at least one visit. In our analysis, there were 271 AD cases with T2DM and 8,431 cases without. Differences in scores were explored using one‐way ANOVA. Effect sizes were calculated using sample means and standard deviations (Cohen's d). Result: The differences in pathology staging between AD‐confirmed individuals with T2DM and those without were statistically significant, with effects ranging from medium (d = ‐0.34; r = ‐0.17) to large (d = 0.53 and 0.51; r = 0.25). The presence of recent or active T2DM was associated with a higher Thal phase of amyloid plaques (μdiff = 1.89) as well as a higher NIA‐AA Alzheimer's disease neuropathologic change, ADNC (μdiff = 1.57). The presence of T2DM was also correlated to a lower Braak stage for neurofibrillary degeneration (μdiff = ‐0.30). Conclusion: These findings suggest that there is more amyloid burden in individuals with AD and T2DM than AD without T2DM. Our results indicate that individuals with T2DM have significantly higher amounts of plaques by Thal stage, as well as higher ABC scores. [ABSTRACT FROM AUTHOR]

The streptozotocin (STZ)-treated rat is a widely studied experimental model of diabetes mellitus (DM). Its pathophysiology includes hypoinsulinemia, hyperglycemia, cardiac hypertrophy, and a cardiomyopathy that is characterized by the presence of diastolic and/or systolic contractile dysfunction. As part of their endocrine function cardiomyocytes in the heart produce and secrete a family of related peptide hormones called the natriuretic peptides that include A-type natriuretic peptide (ANP) and B-type natriuretic peptide (BNP). ANP and BNP levels are variously augmented in patients with hypertension, cardiac overload, in the ventricles of failing or hypertrophied heart, in cardiac heart failure, in acute myocardial infarction (MI), and in some circumstances in DM. In this article, the effects of BNP on ventricular myocyte contraction and Ca2+ transport in STZ-induced diabetic rats have been investigated. BNP concentration was significantly increased in blood plasma and in atrial muscle in STZ-induced diabetic rats compared to age-matched controls. BNP was 11.9 ± 0.9 ng/mL in plasma from diabetic rats compared to 6.7 ± 1.6 ng/mL in controls and 15.8 ± 2.0 ng/mg protein in diabetic atrial muscle compared to 8.5 ± 1.0 ng/mg protein in controls. The heart weight to body weight ratio, an indicator of hypertrophy, was significantly increased in diabetic rat heart (4.3 ± 0.1 mg/g) compared to controls (3.7 ± 0.04 mg/g). The amplitude of shortening was not significantly altered in diabetic myocytes (10.3 ± 0.4%) compared to controls (10.9 ± 0.4%). BNP reduced the amplitude of shortening to a greater extent in diabetic myocytes (8.1 ± 0.6%) compared to controls (10.1 ± 0.4%). The time to peak (TPK) shortening was significantly prolonged in diabetic myocytes (254 ± 8 ms) compared to controls (212 ± 5 ms) and was not additionally altered by BNP. The time to half relaxation of shortening was also significantly prolonged in diabetic myocytes (131 ± 8 ms) compared to controls (111 ± 5 ms). BNP (10−8 to 10−6 M) normalized the time to half relaxation of shortening in diabetic myocytes to that of controls. Time to peak (TPK) shortening of Ca2+ was not different between diabetic and control rats. However, BNP (10−7 M) increases TPK of Ca2+ significantly. The amplitude of the Ca2+ transient was significantly increased in diabetic myocytes (0.42 ± 0.02 Ratio units [RU] ) compared to controls (0.36 ± 0.02 RU) and was not additionally altered by BNP. BNP may have a protective role in STZ-induced diabetic rat heart. [ABSTRACT FROM AUTHOR]

Diabetes mellitus (DM) shows a markedly increased incidence of cardiovascular pathology that leads to hypertension, endothelial macro- and microangiopathy, diabetic nephropathy, and myocardial infarction. Atrial natriuretic peptide (ANP), is a 28 amino acid peptide hormone synthesized mainly by the heart atria and ventricles. It has potent diuretic and natriuretic properties. In this article the effect of long-term DM on blood plasma, kidney, and heart atrial and ventricular ANP concentrations were evaluated in streptozotocin (STZ)-induced 8-month diabetic and control rats by using radioimmunoassay (RIA). Moreover, ANP receptors in STZ-induced, 8-month diabetic rat kidneys were studied by receptor autoradiography. In addition, the expression of ANP concentrations in the kidney of diabetic and control rats was evaluated by means of immunohistochemistry. Body weight loss and increased blood glucose levels were used as indices of DM in the STZ-induced diabetic rats. Our results showed significantly higher ANP concentrations in diabetic plasma ( P < 0.05), kidney ( P < 0.01), heart atria ( P < 0.05), and ventricles ( P < 0.01) compared to controls. We also demonstrated a significant decrease in ANP receptors in the outer cortex ( P < 0.05), juxtaglomerular medulla ( P < 0.05), and papilla ( P < 0.05) of 8-month diabetic rat kidneys compared to controls. The observed increase in ANP levels in plasma and kidney could play a role in the development of diabetic nephropathy: probably by reducing the levels of ANP receptors in diabetic kidney. Furthermore, the role of ANP in the STZ-induced diabetic heart merits additional study. [ABSTRACT FROM AUTHOR]

Long-term adrenalectomy induces a dramatic loss of cells in the dentate gyrus and CA1-CA4 fields of the hippocampus resulting in an impairment of cognitive functions such as spatial learning, memory and exploratory behaviour. Muscarinic M1 and M4 receptor levels in the hippocampus and entorhinal cortex of adult male Wistar rats were examined 3, 14, 30, 90, and 150 days after adrenalectomy. Receptor levels in the entorhinal cortex and the hippocampus were determined by quantitative autoradiography using 125I-M1-toxin-1 and 125I-M4-toxin-1, M1 and M4 subtype selective antagonists, respectively. Moreover, the level of hippocampal M1 and M4 muscarinic receptors were evaluated 1 month after adrenalectomy by immunoblot analysis. Adrenalectomy induced apoptotic processes were examined by analysing apoptotic markers using Western blot analysis. No significant changes were observed in the level of muscarinic M1 receptors in the entorhinal cortex, the dentate gyrus and in the different CA fields of the hippocampus of adrenalectomized (ADX) rats. However, M4 receptors showed a significant decrease in the entorhinal cortex (at 3 days), dentate gyrus and CA4 (at 14 days), CA3 (at 30 days), and CA2 and CA1 (at 90 days) after adrenalectomy. Moreover, a decrease in the level of M4 receptors was detected in ADX rats 1 month after adrenalectomy as compared with sham groups using M4 specific antibody. Apoptotic markers such as PARP and p53 were significantly increased whereas Bcl-2 marker was decreased in ADX rat brain homogenates compared to controls. Our results show that M1 and M4 receptors are differentially affected by adrenalectomy and indicate that these subtypes have different functions in the hippocampus. Our data on time and region-dependent decreases in hippocampal M4 receptors indicate that the M4 receptor subtype is influenced by adrenal hormones and suggest that the M4 receptor might be linked to memory function in the hippocampus. [ABSTRACT FROM AUTHOR]

Abstract: The mamba toxin MT-7 is the most selective ligand currently available for the muscarinic M1 receptor subtype. The toxin binds stably to the receptor and blocks the agonist-induced activation non-competitively. Although its mode of action on M1 receptors is not yet fully understood, some of the toxin properties support an allosteric mechanism. Thus, the toxin fails to elicit a complete inhibition of the binding of either the muscarinic antagonist [3H]N-methyl-scopolamine ([3H]NMS) or the agonist [3H]acetylcholine ([3H]ACh). When added to ligand-occupied M1 receptors, the toxin slows the dissociation rate of [3H]NMS and increases that of [3H]ACh. Site-directed mutagenesis studies have provided important information about the toxin amino acid residues which are critical for the stable binding to the receptor and for the allosteric modulation of antagonist dissociation. In vivo studies have shown that the intracerebral injection of MT-7 causes a long-lasting blockade of M1 receptor, thus providing a tool for the characterization of the functional role of this receptor subtype in discrete brain areas. [Copyright &y& Elsevier]

Glutamate excitotoxicity plays a key role in inducing neuronal cell death in many neurological diseases. In mice, intranasal administration of kainic acid (KA), an analogue of the excitotoxin glutamate, results in hippocampal cell death and provides a well-characterized model for studies of human neurodegenerative diseases. In this study, we describe neurodegeneration and gliosis following intranasal administration of KA in C57BL/6 mice. By using Nissl's staining, neurodegeneration was found in area CA3 of hippocampus, and neuronal apoptosis was demonstrated by enhanced FAS(CD95/APO-1) expression detected by immunohistochemistry and Western blotting. Astrogliosis was exhibited by increased glial fibrillary acidic protein (GFAP) expression in the hippocampus and cortex. We also studied the profile of molecular expression on microglia in C57BL/6 mice. One and 3 days after KA administration, CD45, F4/80, CD86, MHCII, iNOS but not CD40 expression was enhanced or induced on microglia. In summary, KA administration results in an early microglial activation and a prolonged astrogliosis in C57BL/6 mice. © 2004 Wiley Periodicals, Inc. J Neurobiol, 2005 [ABSTRACT FROM AUTHOR]

To study the effects of oestrogen and progesterone on submucosal collagen fibres and vascular plexus of the anal canal.Experiments were performed on sections of the anal canal of ovariectomized rats following 28 daily subcutaneous injections of 17-β oestradiol (n = 6, OVX + E, Group 1), medroxyprogesterone acetate (n = 6, OVX + P, Group 2), both drugs (n = 6, OVX + E + P, Group 3) or vehicle (n = 6, OVX) and after sham surgery without castration or injection (n = 6). Investigations included immunohistochemistry of oestrogen and progesterone receptors and collagen fibres, Western blot analysis of collagen types I and III and counting of perianal vessels by light microscopy.There was positive immunostaining for oestrogen and progesterone receptors in the mucosa and for collagen types I and III in the submucosa in all samples. Type I collagen levels increased significantly with ovariectomy but were normalized with treatment with oestrogen and progesterone. Type III collagen levels decreased after ovariectomy. Administration of oestrogen and progesterone appeared to restore level to near sham values. Semi-quantitative measurement of Type I/III collagen ratios by signal intensity demonstrated a very high ratio after ovariectomy. This appeared to be restored by both oestrogen and progesterone administration either individually or in combination. Mean vessel count was significantly lower in sham animals compared to values in OVX animals (P = 0.006). However, while only oestrogen treatment increased significantly the number of vessels compared to sham animals (P = 0.04), replacement with progesterone did not affect and in combination with oestrogen reduced submucosal vessel number.Oestrogen and progesterone have synergistic effects on collagen types I and III and probably antagonistic effects on the vascular plexus of the anal canal submucosa in adult female rats. [ABSTRACT FROM AUTHOR]

The muscarinic toxin MT7 is the most selective ligand for the muscarinic M1 receptors. Previous studies have shown that the toxin interacts with the antagonist–receptor complex and slows the antagonist dissociation rate, possibly by binding to an allosteric site and impeding the access to and egress from the orthosteric binding pocket. In the present study, we investigated the action of MT7 on agonist-occupied receptors in functional and radioligand binding assays of the cloned human muscarinic M1 receptor expressed in Chinese hamster ovary cells. In time-course experiments, the addition of MT7 rapidly blocked the acetylcholine-stimulated guanosine-5′-O-(3-[35S]thio)triphosphate binding to membrane G proteins. Similarly, in acetylcholine-treated cells MT7 completely stopped the agonist-stimulated [3H]inositol phosphate accumulation. In dissociation experiments using membranes pre-equilibrated with [3H]acetylcholine, the addition of MT7 increased the rate of radioligand dissociation. The data indicate that MT7, while partially stabilizing the antagonist–receptor complex, effectively destabilizes the agonist-occupied muscarinic M1 receptors. [Copyright &y& Elsevier]

Collagen and blood vessels of the urethral submucosa of ovariectomized rats were studied following 28 daily subcutaneous injections of 17-ß estradiol (n=6, group 1), medroxy-progesterone acetate (n=6, group 2), both drugs (n=6, group 3) or vehicle (n=6, control) and after sham surgery without castration or injection (n=6). Investigations included the immunohistochemistry of estrogen and progesterone receptors and collagen fibres, Western blot analysis of collagen types I and III and counting periurethral vessels by light microscopy. Our results showed positive immunostaining with estrogen, progesterone and collagen types I and III in all samples. Collagen type I and III levels were lower in the controls than in the sham group. The other groups showed increases (2>3>1) over the controls with a relatively higher increase in type III. The type I/III collagen ratio progressively decreased (control>1>2>3) below sham levels. The mean vessel count was significantly lower in control than in sham animals (P<0.00001). However, only estrogen treatment significantly increased the vessel number compared to controls (P=0.04). Our results indicate that estrogen and progesterone, alone or in combination, have an effect on collagen types I and III, and that estrogen has an effect on blood vessels of the urethral submucosa in female rats. [ABSTRACT FROM AUTHOR]

In this study we have investigated the levels of prolactin, growth hormone, and insulin-like growth factor-1 in plasma and in tissue extracts of ankle joints of rats with acute or chronic adjuvant arthritis using enzyme immunoassay (EIA) and radioimmunoassay (RIA). We found a stable content of prolactin in plasma of the different groups but a significantly increased concentration of growth hormone was observed in the plasma of the group with chronic arthritis. Moreover, an increased concentration of insulin-like growth factor-1 was noted in the plasma of the acute group. This evidently had returned to normal levels in the chronic group. In contrast, decreased concentrations of prolactin, growth hormone, and insulin-like growth factor-1 were found in tissue extracts of ankle joints of the group with chronic arthritis. The changes in the levels of these hormones in adjuvant arthritis might suggest that they play a role in the pathogenesis of the disease. Understanding the mechanism(s) of hormonal participation in adjuvant arthritis may open new treatment strategies for rheumatoid arthritis and other inflammatory disorders. [ABSTRACT FROM AUTHOR]

Three new toxins acting on muscarinic receptors were isolated from the venom of the black mamba Dendroaspis polylepis. They were called muscarinic toxins α, β, and γ (MTα, MTβ, and MTγ). All of the toxins have four disulphide bonds and 65 or 66 amino acids. The sequences of MTα and MTβ were determined. The muscarinic toxins, of which about 12 have been isolated from venoms of green and black mambas, have 60-98% sequence identity with each other, and are similar to many (about 180) other snake venom components, such as α-neurotoxins, cardiotoxins, and fasciculins. In contrast to the α-neurotoxins, muscarinic toxins do not bind to nicotine acetylcholine receptors. The binding constants of MTα and MTβ were determined for human muscarinic receptors of subtypes m1-m5 stably expressed in Chinese hamster ovary cells. The toxins are less selective than the earlier discovered muscarinic toxins from the green mamba Dendroaspis angusticeps. MTα and the muscarinic toxin 4 from D. angusticeps differ only in a region of three amino acids (residues 31-33), which are Leu-Asn-His in MTα and Ile-Val-Pro in MT4. This difference causes a pronounced shift in subtype selectivity, MTα has high affinity to all subtypes, with KI (inhibition constant) values of 23 nM (m1; pKi = 7.64 ± 0.10), 44 nM (m2; pKi = 7.36 ± 0.06), 3 nM (m3; pKi = 8.46 ± 0.14), 5 nM (m4; pKi = 8.32 ± 0.07), and 8 nM (m5; pKi = 8.09 ± 0.07), MT4 has high affinity only to m1 (Ki = 62 nM) and m4 (87 nM) receptors, and low (Ki > 1 µM) affinity to m2, m3, and m5. The region at positions 31-33 evidently plays an important role in the toxin-receptor interaction. MTβ has low affinity for m1 and m2 receptors (Ki > 1 µM) and intermediate affinity for m3 (140 nM; p Ki = 6.85 ± 0.03), m4 (120 nM; p Ki = 6.90 ± 0.06), and m5 (350 nM; 6.46 ± 0.01). The low affinity of MTβ may reflect a tendency for spontaneous inactivation. [ABSTRACT FROM AUTHOR]