Sibutramine hydrochloride monohydrate is a weight loss agent banned from most global markets due to reports of serious adverse events including death. It is classified as a serotonin-norepinephrine reuptake inhibitor and acts within the central nervous system by inhibiting the reuptake of these neurotransmitters essentially influencing satiety and also energy expenditure. Despite its ban, sibutramine is still available for use in some countries and is often an unlisted ingredient in herbal or natural weight loss products. This leads to the oblivious and unintentional consumption of this compound which is of great concern especially if used by pregnant women. The aim of this study was to investigate the possible toxic and teratogenic effects of sibutramine by using a Spraque Dawley rat and an in ovo chick embryo model. The Sprague Dawley rat was used as in vivo model and animals were divided into three experimental groups, each consisting of 12 animals (6 males, 6 females). Rats were administered sibutramine over a 28 day period according to their assigned experimental groups namely control (C; sterile H2O), Low dose (LD; 1.32 mg/kg) and High Dose (HD; 13.2 mg/kg). On the day of termination blood was collected for various analyses which included biochemical tests for liver and kidney function, hormonal changes as well as the investigation of coagulation profiles. Brain, heart, lung, kidney and liver tissue of each animal was harvested for investigation of tissue and cellular structure. Rats were weighed daily and this data suggested that sibutramine was well tolerated by all animals, with only the female rats in the HD group showing a significant 8.2% decrease in their rate of weight gain. Biochemical data of liver and kidney function in all groups were normal. Thyroid hormone levels were comparable to control values though cortisol levels were lowered in the HD female group, a finding which correlates with the observed weight loss. Investigations of the ultrastructural morphology of the platelets and fibrin networks revealed differences between the experimental groups that are consistent with changes associated with a procoagulable state. Brain, kidney and liver tissue morphology appeared normal upon investigation, the latter confirming the biochemical findings. Examination of cardiac tissue revealed a slight increase in collagen deposition between the muscle fibers and ultrastructural analysis of lung tissue showed thickening of the alveolar walls, decreased intra-alveolar space and drastic increases in collagen deposition in the sibutramine-exposed groups. These findings were dosage dependant. The in ovo model was implemented with ephedrine, a known teratogen, as positive control. Three control groups were included to ensure the efficacy of the method. Eight experimental groups, each containing sixteen eggs, were exposed to four different concentrations of each drug (i.e. 0.5, 2.5, 5.0, 10.0 μmol). The brain, heart, liver and kidneys were harvested on embryonic day thirteen for morphological analysis. Macroscopic evaluation revealed that both drugs caused congenital abnormalities which included ventral wall and limb defects as well as growth retardation and increased mortality. Sibutramine was found to have a greater teratogenic potential than ephedrine. Histological investigation of kidney and brain samples of embryos revealed no morphological differences between the various experimental groups. Livers and hearts of embryos exposed were severely affected by both compounds in a dose dependant manner. Replacement of myocardium with adipose and connective tissue was observed in cardiac tissue, which is characteristic of muscular dystrophy. Severe liver steatosis was also evident. In conclusion, results from this animal-based study show that, at concentrations which are not toxic to the liver or kidneys, sibutramine administration led to increased coagulation, moderate cardiac and excessive lung fibrosis within the Sprague Dawley rat model. This indicates significant toxicity with the cardiac and respiratory system being more susceptible targets. In addition sibutramine was shown to possess greater teratogenic effects than ephedrine. Both drugs caused cardiac dystrophy and liver steatosis resulting in extensive liver and heart damage. Understanding the underlying mechanisms involved in the pathogenesis of these findings strongly emphasize an important area for future research. / Dissertation (MSc)--University of Pretoria, 2014. / tm2015 / Anatomy / MSc / Unrestricted

Thyroxine is the main thyroid gland's hormone. The state, when the thyroid gland does not produce enough of it into the bloodstream is called hypothyroidism. Hypothyroidism is related with several health complications; therefore it is required to take replacement therapy in adequate doses. Concerning pregnant women, it is important especially to keep the blood level of thyroxine in the normal, because increasing or decreasing of it, has an adverse effect on the health of the mother and also on the normal child development. The objective of my thesis was to describe malformations spectra of thyroxine, to find out the beginning of its embryotoxicity dose range for chick embryos, and recalculate this value for human embryos, allowing us to decide, if the level of thyroxine was increased by a replacement therapy, this could be embryotoxic for human. The experimental part of my work was to search an alternative method for testing embryotoxicity on chick embryos in ovo - CHEST, testing of embryotoxic potential of the thyroxine. Embryotoxicity is a feature of the external factors affecting the embryo, it may manifest as lethality, growth retardation, and teratogenicity; which is an ability of the external factor to induce the developmental defect. The most common manifestation of embryotoxicity in this...

Neural tube defects (NTDs) are malformations affecting about 2.6/1000 births worldwide, and 1/1000 in the United States. Their etiology remains unknown, and is likely due to interaction of genetic susceptibility factors with environmental exposure. Of the many environmental agents considered to potentially contribute to NTD risk, arsenic is one that is surrounded in controversy. We have developed a model system utilizing maternal intraperitoneal (I.P.) exposure on E7.5 and E8.5 to As 9.6 mg/kg (as sodium arsenate) in a normal inbred mouse strain, LM/Bc/Fnn, that is sensitive to arsenate-induced exencephaly. We investigated arsenate induced gene expression changes using DNA microarrays of embryonic anterior neural tube tissue, as well as monitoring of metabolic function in conjunction with the administration of select compounds to rescue the normal phenotype. Finally, to address questions concerning the importance of route of administration and potential maternal toxicity, a teratology study was performed using three arsenate doses administered orally. Regarding the gene expression study, we identified several candidate genes and ontology groups that may be responsible for arsenate’s teratogenicity. Genes include: engrailed 1 (En-1), platelet derived growth factor receptor alpha (Pdgfrα) and ephrinA7 (EphA7). Gene ontology groups identified include oxidative phosphorylation, redox response, and regulation of I-kappaB kinase/NF-kappaB cascade. Acute arsenate exposure induced disruption of mitochondrial function and dependent glucose homeostasis: subsequent hyperglycemia was teratogenic. Maternal treatment with insulin or n-acetyl cysteine, an antioxidant and precursor of glutathione synthesis, proved highly successful in rescuing both the normal phenotype, and to differing degree, the maternal hyperglycemia. Maternal oral arsenate administration also resulted in exencephaly, with exposed embryos exhibiting a positive linear trend with arsenate dosage. There were also linear trends in the relationships between arsenate dose and anomalies involving several components of the axial skeleton: the vertebrae and calvarium. There was no evidence of maternal toxicity as shown by lack of differences in maternal body weight gain, liver, and kidney weights. In conclusion, maternal arsenate exposure (regardless of exposure route) was teratogenic in our model, primarily causing NTDs. Responsible mechanisms may involve disruption of redox and glucose homeostasis as well as expression of established NTD candidate genes.

Neural tube defects (NTDs) are malformations affecting about 2.6/1000 births worldwide, and 1/1000 in the United States. Their etiology remains unknown, and is likely due to interaction of genetic susceptibility factors with environmental exposure. Of the many environmental agents considered to potentially contribute to NTD risk, arsenic is one that is surrounded in controversy. We have developed a model system utilizing maternal intraperitoneal (I.P.) exposure on E7.5 and E8.5 to As 9.6 mg/kg (as sodium arsenate) in a normal inbred mouse strain, LM/Bc/Fnn, that is sensitive to arsenate-induced exencephaly. We investigated arsenate induced gene expression changes using DNA microarrays of embryonic anterior neural tube tissue, as well as monitoring of metabolic function in conjunction with the administration of select compounds to rescue the normal phenotype. Finally, to address questions concerning the importance of route of administration and potential maternal toxicity, a teratology study was performed using three arsenate doses administered orally. Regarding the gene expression study, we identified several candidate genes and ontology groups that may be responsible for arsenate’s teratogenicity. Genes include: engrailed 1 (En-1), platelet derived growth factor receptor alpha (Pdgfrα) and ephrinA7 (EphA7). Gene ontology groups identified include oxidative phosphorylation, redox response, and regulation of I-kappaB kinase/NF-kappaB cascade. Acute arsenate exposure induced disruption of mitochondrial function and dependent glucose homeostasis: subsequent hyperglycemia was teratogenic. Maternal treatment with insulin or n-acetyl cysteine, an antioxidant and precursor of glutathione synthesis, proved highly successful in rescuing both the normal phenotype, and to differing degree, the maternal hyperglycemia. Maternal oral arsenate administration also resulted in exencephaly, with exposed embryos exhibiting a positive linear trend with arsenate dosage. There were also linear trends in the relationships between arsenate dose and anomalies involving several components of the axial skeleton: the vertebrae and calvarium. There was no evidence of maternal toxicity as shown by lack of differences in maternal body weight gain, liver, and kidney weights. In conclusion, maternal arsenate exposure (regardless of exposure route) was teratogenic in our model, primarily causing NTDs. Responsible mechanisms may involve disruption of redox and glucose homeostasis as well as expression of established NTD candidate genes.

Magister Scientiae (Medical Bioscience) - MSc(MBS) / The incidence of non-communicable diseases is increasing worldwide, with South Africa being no exception. Non-communicable diseases are classified as non-infectious and are often referred to as lifestyle diseases as they are caused by common, modifiable risk factors such as unhealthy diet, obesity, tobacco use and lack of physical activity. Due to the increasing prevalence of childhood obesity diseases such as fatty pancreas and fatty liver are becoming more common. Cardiovascular disease, and more specifically atherosclerosis is the underlying cause in most adult deaths. Disease pathogenesis starts in childhood and can be detected via Aortic intima-media thickness (IMT). The developmental origins of health and disease hypothesis (DOHaD) proposes that exposures in-utero may result in persistent adaptations including alterations in metabolism.

In 1996, the Institute of Medicine made an initial step towards addressing the confusion and controversy regarding the diagnosis of fetal alcohol syndrome (FAS) by proposing a classification scheme and calling for research to evaluate its validity and clinical utility. Previous research evaluated memory, executive functions, and behaviour problems in FAS. Prior to the present study, however, there had not been an empirical evaluation of the existence of a spectrum of diagnostic subgroups or an evaluation of subgroup functioning on neuropsychological components of attention during the pre-teen and adolescent years. Part 1 of this study used categorical data regarding diagnostic domains to determine if an a priori spectrum of four subgroups could be identified. This spectrum included FAS and three fetal alcohol effect (FAE) subgroups, which were defined using teratogenic theory, previous research findings, and logic. The sample consisted of 112 children with a confirmed history of excessive prenatal alcohol exposure. Part 2 evaluated the continuity and comparability of the CNS dysfunction subgroups exhibited by assessing neuropsychological components of attention using models by Mirsky and Conners. The sample consisted of 30 children and subgroups were matched on age, sex, and living situation. Results identified 3 of the 4 potential subgroups. All subgroups exhibited a clinically significant attention deficit. After adjusting for IQ, the FAS and FAE subgroups had comparable levels of functioning on all components of attention with one exception. On the sustain component, the FAE subgroups had more difficulties than the FAS subgroup in maintaining a consistent response-speed in response to changes in the length of time between targets. This study provides empirical and theoretical support for the validity and clinical utility of a spectrum of fetal alcohol subgroups consistent with the IOM's classification. It furthers a theoretical understanding of the dose-response effects of alcohol as a teratogenic agent. It suggests that attention regulation functions are especially vulnerable to the damage caused by prenatal alcohol exposure. The findings emphasize the importance of obtaining a history of prenatal alcohol exposure in individuals presenting with neuropsychological difficulties, and developing treatment programs for pregnant women with an alcohol addiction.

No description available.

One of the first embryonic structures generated during early human development is the neural tube. The embryonic process of neurulation, including neural tube closure, is necessary for proper brain and spinal cord development, whereas improper closure leads to neural tube defects including anencephaly, spina bifida, and craniorachischisis. The mechanism by which these defects occur is unknown, but some evidence suggest that redox disruption may play a role. Cellular redox state is important in regulating key processes during neural tube closure, including differentiation, proliferation, gene expression, and apoptosis. This study aims to determine whether redox potential shifts and these key processes are affected similarly or differentially after treatment with three neural tube defect-inducing developmental toxicants: ceramide (C2), valproic acid (VPA), and fumonisin (FB1). Using the P19 cell model of neurogenesis, in both undifferentiated and terminally differentiated cells, we analyzed glutathione (GSH) redox (Eh) potential to evaluate the effect of each toxicant over time. We show that in C2 and VPA treated cultures an oxidizing shift occurs, but interestingly, FB1 treatment results in a reducing shift in embryonic GSH Eh as compared to untreated cultures. Using the chick embryo model, comparable redox shifts were observed as were seen in P19 cells, supporting similarity between the models. To better understand how differential shifts in the redox state can result in similar defects, we then examined potential variances in neuronal differentiation and cellular proliferation, survival, metabolism, adhesion, and gene expression under each treatment. We report changes to cellular and embryonic endpoints that support dysmorphogenesis, likely the result of oxidizing or reducing stress that altered redox state. These results support the need for broad comparative analyses such as this to determine whether toxicants that cause the same types of defects, whether NTDs or others, act through similar or different mechanisms. This can better inform preventative measures used to reduce the risk and occurrence of birth defects.

Previous research has shown a relationship between prenatal teratogenic exposure and impaired cognitive functioning. However, data regarding the long-term outcome of prenatal teratogenic exposure are minimal. The present study investigated the long-term neuropsychological functioning (specifically attention and memory) of adults prenatally exposed to alcohol or phenylalanine, and examined whether there was evidence to suggest that there are effects specific to individual teratogens. Using a battery of attention and memory measures the performance of 17 adults diagnosed with Fetal Alcohol Syndrome (FAS) and 13 adults with Maternal Phenylketonuria Syndrome (MPKUS) was assessed. In order to identify the pattern of deficits associated with prenatal teratogenic exposure, an age and CA and IQ matched control group was assessed. Attention was broadly assessed using Mirsky et al.'s (1991) neuropsychological model of attention. The memory and learning tests administered included a number of well standardized measures of verbal learning, verbal and visual recall, delayed recall, and recognition. Paired comparisons between the FAS group and age and CA and IQ matched controls indicated a unique pattern of attention and memory deficits consistent with previous research with children and adolescents. Specifically, adult individuals with FAS appear to have deficits in acquisition of new material, delayed recall of verbal material and in response inhibition. Paired comparisons between the MPKUS group and CA and IQ matched controls indicated that the pattern of attention and memory deficits seen in adults with MPKUS is difficult to distinguish when the effect of IQ is removed. A randomized block design using IQ as the blocking variable and group (FAS, MPKUS, or Controls) as the treatment variable was utilized to examine the question of whether the two prenatal teratogen groups differ from one another and from Controls in terms of attention and memory ability. Ten blocks of three participants (FAS, MPKUS and Control) matched on IQ were formed. The randomized block analyses revealed few differences between the groups and failed to reveal a number of the differences found in the paired comparisons between the prenatal teratogen groups and the CA and IQ matched Control group. Possible reasons for these differences are discussed.

Fetal Alcohol Syndrome (FAS) is a preventable cause of mental retardation and is the severest category within Fetal Alcohol Spectrum Disorder (FASD). As gestational alcohol exposure affects fetal cognitive functioning, children with FAS present with intellectual deficits. Unfortunately FASD prevalence rates are increasing amongst infants and school-going children. The main goal of this study was to compare the neurodevelopmental subscales of infants diagnosed with FAS, Partial FAS and non- FAS. Seventy-four infants with confirmed FAS, Partial FAS or Non- FAS diagnoses were assessed using the Griffiths Mental Developmental Scale. Development assessed at 7-12 and 17-29 months of age showed that, regardless of a FAS, PFAS or Non-FAS diagnosis, all infants performed weaker at their assessment at 17-29 months. The Subscales significantly affected included Personal-Social, Eye- Hand Coordination and Performance. The infants with FAS and PFAS displayed the most marked developmental delays. From this study it can be concluded that there are definite neurodevelopmental profiles for infant's diagnosed with FAS, PFAS and/or Non-FAS, highlighting the significant impact of prenatal alcohol exposure on various aspects of infant development. / Social work / M.Diac.