Experimental and toxicologic pathology : official journal of the Gesellschaft für Toxikologische Pathologie
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Exp. Toxicol. Pathol. · Sep 1998
Cardiovascular function and brain metabolites in normal weight and intrauterine growth restricted newborn piglets--effect of mild hypoxia.
In order to clarify the influence of intrauterine growth restriction on systemic hemodynamics, catecholamine response, and regional distribution of brain energy metabolites per se and during mild hypoxic episodes a study was performed in thirty newborns with a well-characterized state of intrauterine and intra-natal development. Thirty animals were divided into fifteen normal weight piglets (NW) and fifteen intrauterine growth restricted (IUGR) piglets according to their birth weight. Category "NW" covered animals with a birth weight of > 40th percentile; IUGR category covered animals with a birth weight of > 5th and < 10th percentiles. ⋯ In summary, this investigation provides information on cardiovascular functions and brain metabolites of normal weight and naturally occurring growth restricted newborn piglets. Mild hypoxemia was well-tolerated from both animal groups. It is suggested that lactate may play a significant role as a source for brain energy production in the newborn IUGR piglets.
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Exp. Toxicol. Pathol. · Mar 1998
Body weight distribution and organ size in newborn swine (sus scrofa domestica) -- a study describing an animal model for asymmetrical intrauterine growth retardation.
Normal growth is the expression of the genetic potential to growth which is neither abnormally constrained nor promoted by internal or external factors. Restricted fetal growth is common in human pregnancy and is associated with increased perinatal morbidity and mortality. Because of ethical restrictions, pathogenetical studies are necessarily dependent on appropriate animal models. ⋯ Gravimetrical estimation showed clearly that body weight variety is most probably caused by alterations of placental functioning. Severe alterations resulted in asymmetrical growth retardation, which was proved by a significantly increased brain to liver ratio in animals with a body weight < 10th centile. Thus, evidence is provided that naturally occurring asymmetrical intrauterine growth restricted newborn piglets can be identified simply by body weight measurement, so that convenient conditions are given for pathogenetically motivated studies on intrauterine compromised newborns.
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Exp. Toxicol. Pathol. · Dec 1997
Changed systemic and cerebral hemodynamics and oxygen supply due to gradual hemorrhagic hypotension induced by an external PID-controller in newborn swine.
An experimental design including an external closed-loop PID-(proportional-integral-differential-)controller is presented which enables the induction of gradual hemorrhagic hypotension at different stages of blood flow reduction up to stages of critically disturbed systemic and regional hemodynamics and oxygen supply. For this purpose nine newborn piglets (12-26 hours old, body weight 1626+/-160 g) were anesthetized and artificially ventilated. Gradual hemorrhagic hypotension was induced at four different steady state stages (stage 1 = 60 mmHg; stage 2 = 50 mmHg; stage 3 = 40 mmHg; stage 4 = 35 mmHg) every 30 minutes by gradual blood withdrawal using external PID controller equipment. ⋯ Brain cortical oxygen consumption was maintained up to stage 2, reduced by about 20% at the next stage of hemorrhagic hypotension (p<0.05) and reached the lowest level of about 50% from baseline at stage 4 (p<0.05). Excellent accuracy and stability was shown at each stage for the external PID controller equipment, so that each given setpoint of the instantaneous mean arterial blood pressure was reached and stabilized even at the lowest hypotensive stage (stage 1: 59.53+/-0.23; stage 2: 50.03+/-0.56; stage 3: 39.18+/-1.75; stage 4: 35.28+/-0.45 mmHg (mean+/-SD)). We conclude that the experimental design presented, with an external PID controller to induce gradual hemorrhagic hypotension in newborn piglets is sufficient for producing functional states with changed systemic and cerebral features with high stability and accuracy, enabling a systematic study of disturbed regional hemodynamics and energy metabolism under steady state conditions even under critically changed states of the systemic cardiovascular regulation.
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Exp. Toxicol. Pathol. · May 1995
Asbestos-related diseases and asbestos types used in the former GDR.
In the period from 1960 to 1990 about 1.4 million tonnes of asbestos were imported by the former German Democratic Republic (GDR) and mainly processed into asbestos-cement products for the building industry. The production was concentrated in the former counties of Magdeburg and Dresden. In the past, asbestos was primarily used as insulation and fire prevention material, etc. in the large-scale chemical industry. ⋯ Very small amounts of amphiboles came from Mozambique, but they were not processed in the counties of Magdeburg and Halle. In the German Federal State of Saxony-Anhalt, approx. 600 asbestoses, almost 2,700 pleural changes caused by asbestos, 843 asbestos-induced mesotheliomas and 787 bronchial and laryngeal carcinomas caused by asbestos were recorded in the period from 1960 to 1990. A considerable percentage of the mesotheliomas are solely due to exposure to chrysotile asbestos.