Tomasz Stępień

Pathology of mitochondria in MELAS syndrome: an ultrastructural study

Ultrastructural changes in skeletal muscle biopsy in a 24-year-old female patient with clinically suspected mitochondrial encephalomyopathy lactic acidosis and stroke-like episodes (MELAS) syndrome are presented. We observed proliferation and/or pleomorphism of mitochondria in skeletal muscle and smooth muscle cells of arterioles, as well as in pericytes of capillaries. Paracrystalline inclusions were found only in damaged mitochondria of skeletal muscle. Genetic testing revealed a point mutation in A3243G tRNALeu(UUR) typical for MELAS syndrome. We conclude that differentiated pathological changes of mitochondria in the studied types of cells may be associated with the different energy requirements of these cells.

Intracerebral hemorrhage in the context of cerebral amyloid angiopathy and varied time of onset of cerebral venous thrombosis: a case report

In patients with cerebral venous thrombosis (CVT) the incidence of intracerebral hemorrhage (ICH) is estimated at about 37% and subarachnoid hemorrhage (SAH) at 1% of patients. A case with coincident occurrence of ICH, SAH and CVT in a patient with cerebral amyloid angiopathy (CAA) is reported. A 79-year-old woman was admitted to the Neurological Department after the occurrence of generalized seizures, the first in her life. On admission she was unconscious with right hemiparesis and deviation of eyes to the left. On computed tomography (CT) scan many hemorrhagic infarcts were present in the frontal, parietal, temporal and left occipital lobes. Angio-CT revealed thrombosis in the right transverse sinus, right internal carotid vein and superior sagittal sinus. Her state slowly deteriorated. She died after 6 days. Neuropathologically, many hemorrhagic infarcts were observed in cortical regions in the vicinity of veins with thrombosis and in the white matter. The varied time of onset of thrombosis of the right sigmoid sinus, right superior petrosal sinus, superior sagittal sinus, right transverse sinus and the proximal part of the right internal carotid vein was confirmed. cerebral amyloid angiopathy in brain vessels was diagnosed. Subarachnoid hemorrhage is a very uncommon presentation of CVT and may coexist with CAA. We can only speculate that CAA may have an effect on vein destruction and can promote cerebral vein thrombosis and in consequence also predispose to intracerebral hemorrhage and subarachnoid hemorrhage. The most probable cause of extensive thrombosis was a coagulation disorder.

Effects of amphetamine administration on neurogenesis in adult rats

In our study expression of phospho-(Ser-10)-histone H3 (pH3S10), a marker for the early stage of neurogenesis, and cellular early response genes were investigated using c-Fos protein as an example of a transcription factor in the neurogenic process in rats. Neurogenesis in the adult brain is regulated by endo- and exogenous factors, which influence the proliferation potential of progenitor cells and accelerate the dendritic development of newborn neurons. D-amphetamine, a psychoactive substance, is one of the exogenous factors able to influence the process of neurogenesis. The rats were injected with D-amphetamine at a dose of 1.5 mg/kg/body weight (b.w.) under one administration scheme. Analysis of the pH3S10 and c-Fos expression levels in the group of D-amphetamine administered rats provided evidence of enhanced expression of these proteins in the regions of neurogenesis occurrence in rats. However, conclusions concerning stimulant effects of amphetamine on neurogenesis should be formulated with great caution, taking into account amphetamine dosage and the administration scheme. It should also be remembered that doses of psychoactive substances used in animal models can be lethal to humans..