Mammillary Bodies in Alzheimer's Disease: A Golgi and Electron Microscope Study.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder, characterized by irreversible memory decline, concerning no rarely spatial memory and orientation, alterations of the mood and personality, gradual loss of motor skills, and substantial loss of capacities obtained by previous long education. We attempted to describe the morphological findings of the mammillary bodies in early cases of AD. Samples were processed for electron microscopy and silver impregnation techniques. The nuclei of the mammillary bodies demonstrated a substantial decrease in the neuronal population and marked abbreviation of dendritic arbors. Decrease in spine density and morphological abnormalities of dendritic spines was also seen. Synaptic alterations were prominent. Alzheimer's pathology, such as deposits of amyloid-ß peptide and neurofibrillary degeneration, was minimal. Electron microscopy revealed mitochondrial alterations and fragmentation of Golgi apparatus, associated frequently with synaptic pathology.

The hypothalamus in Alzheimer's disease: a Golgi and electron microscope study.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder, characterized by irreversible decline of mental faculties, emotional and behavioral changes, loss of motor skills, and dysfunction of autonomic nervous system and disruption of circadian rhythms (CRs). We attempted to describe the morphological findings of the hypothalamus in early cases of AD, focusing our study mostly on the suprachiasmatic nucleus (SCN), the supraoptic nucleus (SON), and the paraventricular nucleus (PVN). Samples were processed for electron microscopy and silver impregnation techniques. The hypothalamic nuclei demonstrated a substantial decrease in the neuronal population, which was particularly prominent in the SCN. Marked abbreviation of dendritic arborization, in association with spinal pathology, was also seen. The SON and PVN demonstrated a substantial number of dystrophic axons and abnormal spines. Alzheimer's pathology, such as deposits of amyloid-ß peptide and neurofibrillary degeneration, was minimal. Electron microscopy revealed mitochondrial alterations in the cell body and the dendritic branches. The morphological alterations of the hypothalamic nuclei in early cases of AD may be related to the gradual alteration of CRs and the instability of autonomic regulation.

The fine structure of ependymomas.

Electron microscopy is a useful diagnostic technique in order to confirm or establish a definitive diagnosis in brain tumors that may have an atypical histological pattern, which requires a concrete diagnosis. In ependymomas, electron microscopy reveals morphological characters that have a pathognomonic diagnostic value, therefore allowing a definitive diagnosis. The main fine structural criteria of ependymomas consist of the numerous microvilli and cilia, which are incorporated in the cell body or extended freely in the intracellular space; the centriole or blepharoplast, which is located in the basis of the cilia; the large number of the fragmented microtubules in the perikaryon and the cellular processes (any small cellular projection into the neutrophil or intracellular space); the junctional apparatus between the cells, such as zonula adherens, zonula occludens and puncta adherentia; the basement membrane-like structure, seen in papillary ependymomas and ependymomas of the filum terminale; and the elongated cells in the loose intracellular space, commonly seen in myxopapillary ependymomas.

The vascular factor in Alzheimer's disease: a study in Golgi technique and electron microscopy.

Although the etiopathological background of Alzheimer's disease (AD) is mostly associated with the deposition of Αß-peptide, the hyperphosphorylation of τ protein, the synaptic pathology and the mitochondrial alterations, the vascular factor may play substantial role in plotting the multifactorial pattern of the disease. We attempted to study the blood capillaries in the hippocampus, the acoustic, the visual and the parietal cortex in twelve early cases of Alzheimer's disease. Samples were processed for Golgi silver impregnation technique and electron microscopy. The morphological findings were compared with normal controls. The study of the brain capillaries in cases of AD, revealed numerous fusiform dilatations, tortuosities, abnormal branching and fusion, though the morphometric estimation revealed a decrease of the number of capillaries per mm(3) in comparison with normal control brains. The ultrastructural study revealed mitochondrial abnormalities in the endothelial cells of a substantial number of capillaries and marked degeneration of the pericytes. Perivascular microglial proliferation was also prominent in the hippocampus and the parietal lobe. Our findings both in Golgi staining and electron microscopy plead in favor of the essential role that the microvascular alterations may play in the broad pathogenetic spectrum of AD.

Brain SPECT findings of anosognosia in Alzheimer's disease.

Anosognosia is a common symptom of dementia. The aim of this study was to evaluate the contribution of different regions of the brain to anosognosia in Alzheimer's disease (AD) brains using single photon emission computed tomography (SPECT). Forty-two patients with AD were included in this study. After clinical interviews with the patients and their relatives, the patients were divided into two groups: Anosognosia and No-anosognosia. The patients were studied regarding the severity of dementia. They underwent SPECT with HMPAO and regional cerebral blood flow (rCBF) was measured. Regional CBF significantly differed between Anosognosia and No-anosognosia groups in right prefrontal (P < or = 0.02), right inferior parietal (P < or = 0.00), and right (P < or = 0.01) and left (P < or = 0.01) medial temporal cortex. There was a significant correlation between the severity of dementia and rCBF in medial temporal regions. When comparisons were made between mild and moderate stages separately, the 'right inferior parietal region' was the common region which showed hypoperfusion in both anosognosia subgroups. We conclude that anosognosia may be a reflection of functional impairment in right prefrontal, right frontal and especially right inferior parietal regions in AD.

Evaluation of dopaminergic function in frontotemporal dementia using I-FP-CIT single photon emission computed tomography.

Extrapyramidal symptoms are observed in frontotemporal dementia (FTD). (123)I-FP-CIT (DaT scan) single photon emission computed tomography (SPECT) can detect loss of presynaptic dopamine transporters in the striatum. We aimed to evaluate the dopaminergic status of the striatum in patients with FTD using DaT scan. Seven patients (age range 65-76 years), who fulfilled the Neary criteria and in whom the diagnosis of FTD was confirmed by hexamethylpropyleneamine oxime SPECT, were included in the study. The severity of the extrapyramidal symptoms was evaluated by the motor part of the Unified Parkinson's Disease Rating Scale (UPDRS). SPECT using (123)I-FP-CIT was done. A (region - occipital)/occipital ratio was calculated for the striatum, putamen and caudate nucleus. The results were compared with those of the 7 age-matched normal controls. The uptake of the radiotracer in the right and left striatum was reduced to 62% (p = 0.000) and 68% (p = 0.000), respectively, compared to controls. The motor UPDRS score of the patients with FTD showed a negative correlation to the uptake of the radiotracer. The presynaptic dopamine transporter in FTD is impaired, related to the severity of the extrapyramidal symptoms. Since an effective treatment for FTD is still to be established, there is a need for evaluating the efficacy of dopaminergic drugs.

Morphological alterations of the synapses in the locus coeruleus in Parkinson's disease.

Parkinson's disease is the most common movement disorder in the broad spectrum of neurodegenerative diseases, associated frequently with gradual decline of the higher mental faculties. From the morphological point of view it is characterized by the degeneration of a substantial number of dopaminergic neurons of the substantia nigra and a considerable degeneration of neuronal networks in locus coeruleus, putamen, globus pallidus, thalamus and some areas of the cortex of the brain hemispheres. Filamentous inclusions, in the form of Lewy bodies and Lewy neuritis, composed mainly of alpha synuclein, been the hallmark of diffuse Lewy body dementia, have been described in the neurons of the substantia nigra in many cases of Parkinson's disease associated with dementia. In previous studies we have described the morphological alterations in the synapses in the caudate nucleus and the globus pallidus in cases of Parkinson's disease. In the present study we attempted to describe the morphological and morphometric alterations of the locus coeruleus in patients who suffered from Parkinson's disease with normal cognitive function and in patients who suffered from Parkinson's disease associated with dementia, comparing them with normal controls. The morphological alterations of the neurons, the dendrites, the retrograde axonic collaterals and the synapses were more impressive in cases of Parkinson's disease associated with dementia than in Parkinson's disease with normal cognitive function. The majority of the synapses demonstrated changes in size and shape of the pre- and postsynaptic components, polymorphism of the synaptic vesicles and marked morphological alterations of the mitochondria. The morphological alterations of the synapses in cases of Parkinson's disease associated with dementia, plead in favor of the importance of the neuronal circuits of locus coeruleus in cognitive functions.