Marietta R. Issidorides

Altered chromatin ultrastructure in neutrophils of schizophrenics

IN spite of reports of altered nuclear morphology of blood cells1–3 and evidence advocating the participation of genetic factors in schizophrenia4,5, little attention has been paid to the possibility that altered chromatin is associated with this mental illness. Since research in this area may further the understanding of the mechanisms underlying the disease, we compared the chromatin of schizophrenics and normal subjects6,7, using the neutrophil granulocyte as a model of fully differentiated, non-dividing cells with fixed heterochromatisation. Our approach was based on current knowledge of chromatin8–10 and focused on the particular roles of the various histone fractions in determining chromatin structure and function11,12. The results obtained from the initial study6 showed that schizophrenics differ from controls in their nucleohistone staining pattern. This is characterised mainly by an increased availability of arginine-rich histones7 to the anionic phosphotungstic acid–haematoxylin (PTAH) staining reagent13. We interpreted this as indicating an increased readiness of the nucleohistones in the schizophrenics to undergo conformational changes leading to unmasking of such proteins. Considering the role of lysine-rich histone H1 in cross linking the chromatin11,12,14, we tentatively proposed that in schizophrenics histone H1 tends to dissociate more readily from the chromatin complex.

Neuronal vascular relationships in the zona compacta of normal and parkinsonian substantia nigra

Abstract Observations were made on neurons of the substantia nigra in 10 cases of idiopathic Parkinsonism and 5 age-matched controls. It was found that the melanin-containing neurons of the zona compacta in the normal brain have a close spatial relationship with the blood circulation. The capillary walls appear fused to the membranes of neuronal perikarya and processes. In the Parkinsonian zona compacta the close contact between nigral neuron and capillary is lost. The findings suggest that this is due to the infiltration of the proliferated glia between cell surface and capillary wall. This neuronal vascular contact in the zona compacta of the normal brain must be of importance for the functional metabolism of this area, since interruption of this contact was the only detectable nigral lesion in several patients with overt symptoms of recent date. Histochemical reactions of normal and Parkinsonian melanin-containing neurons showed that the nigral cells of the patients have a larger amount of lipofuscin component in the melanin area than those of the controls. Increased basophilia was observed in the Parkinsonian neurons and was inversely related to their melanin content. It is interpreted as an expression of reduced firing activity, indicating regression of function.

Tyrosine hydroxylase-immunoreactive neurons in paraventricular and supraoptic nuclei of the human brain demonstrated by a method adapted to prolonged formalin fixation

We studied the distribution of tyrosine hydroxylase (TH) immunoreactive (IR) neurons in the adult human hypothalamus using a modification of the peroxidase-antiperoxidase immunohistochemical method which can be applied on autopsy brain material following prolonged formalin fixation. We observed that most of the TH-IR perikarya localized within the paraventricular (PVN) and supraoptic (SON) nuclei were large and showed homogeneous staining over the entire cytoplasm and processes. These results show that in the human brain a large population of neurons within the neurosecretory nuclei are able to synthesize a catecholamine.

Lewy bodies in parkinsonism share components with intraneuronal protein bodies of normal brains

SummaryHistochemical characteristics of the Lewy bodies, in catecholamine neurons of 10 Parkinsonian patients, were compared to those of the sperical protein bodies, the basic protein-rich markers of catecholamine neurons in man. Special methods for proteins and lipids showed that the core of the Lewy bodies, in the neurons of the locus coeruleus and the substantia nigra, contains basic proteins and lipids normally found in the protein bodies. Acid fuchsin and the lipid-soluble fluorescent dye rhodamine B stained the entire core of the Lewy body in the parkinsonian brains and the entire sphere of the protein body in the control brains. Bromsulfophthalein, another acidic dye, which selectively binds to the enzyme gluthathione-S-transferase, had affinity only for a ring-like lamina at the outer layer of the core of the Lewy body and for the outer rim of the protein body. These results demonstrate that Lewy bodies and protein bodies contain similar macromolecular components, that is lipids and two different types of proteins, which also show similar stratification in the two structures. On the other hand, the presence in several neurons of the Parkinsonian patients, of aggregates representing transitional forms between protein bodies and Lewy bodies, indicates that abnormalities of protein bodies precede, and are somehow linked to Lewy body production.

Cellular Effects of Chronic Cannabis Use in Man

Recent experimental research on cannabis yielded results indicating that use of this drug may lead to abnormalities of cellular metabolism with consequent functional aberrations potentially harmful to man’s physical health, mental health, or both [6]. Yet however informative and eventually useful these findings may be in elucidating the drug’s mode of action, they are not directly applicable to man. The adequately documented species differences in the action of cannabis [1] as well as the fact that animal experimental conditions hardly simulate cannabis smoking by man are but two of a series of factors to be considered when one attempts to extrapolate experimental findings from animals to man.

Peripheral blood lymphocytes of bipolar affective patients have a histone synthetic profile indicative of an active cell state

1. Although abnormalities of the immune system have been described in depression, no information exists regarding the biochemical parameters which could characterize the physiological state of lymphocytes from patients with bipolar affective disorder. 2. Lymphocytes of normal control subjects are known to be in the Go resting phase of the cell cycle. Histone synthesis is characteristically different during the Go, G1/G2 and the S phases of the cell cycle. As such, it can be used as a biochemical marker with which to distinguish between cycling and noncycling cells. 3. In order to investigate the possibility of whether or not the lymphocytes of patients with bipolar affective disorder are in an activated state, typical of cycling cells, total histone and histone variant synthesis were analysed in peripheral blood lymphocytes of a group of 12 patients with bipolar affective disorder and 7 normal controls. 4. According to the histone variant synthesis pattern, lymphocytes of patients in normothymia have values similar to those of controls, i.e., of noncycling cells, while patients in either the depressed or the manic phase have values intermediate to those of resting and cycling cells. 5. This study shows that histone synthesis can perhaps be used as a biochemical parameter of possible significance in differentiating amongst the three phases of the illness.

Chromatin alterations in leukocytes of first-episode schizophrenic patients.

Studies of peripheral blood leukocytes of schizophrenic patients have shown in electron microscopy (EM) that decondensation of the chromatin constitutes a biological marker indicating increased genomic expression. Since this increase depends on chromatin relaxation by dissociation of lysine-rich histone H1 from nucleosomes, with exposure of arginine residues of core histones, the ratio of arginine to lysine residues in each nucleus represents a reliable measure of activation. Lysine- and arginine-rich proteins are demonstrable in light microscopy (LM), differentially, as yellow and black, respectively, with the ammoniacal silver reaction (ASR). Application of ASR on leukocyte pellets before they are dehydrated and embedded in epoxy resins gives reliable results in semithin sections. In thin sections the ASR method localizes only the amino acid arginine by forming deposits of electron-opaque particles, visualized in the EM. Leukocytes of 12 first-episode schizophrenic patients and 5 controls were used. Light micrographs of the semithin sections were inserted in a personal computer. The percentage of lysine and arginine was measured in 300 nuclei per subject. Morphometry showed that lymphocytes of schizophrenic patients have increased ratios of arginine to lysine, compared to controls, indicating activation; neutrophils of the patients have even a higher ratio, indicating an abnormal condition of the genome. Chromatin conformational changes are also evident by phosphotungstic acid hematoxylin (PTAH) block staining, which reveals condensed chromatin as an electron-lucent area in the nuclei, and decondensed chromatin as an electron-dense area. Because decondensed chromatin is a biological marker of schizophrenia, the efficacy of these methods to demonstrate this particular state offers a tool for early diagnosis, since first-episode schizophrenic patients have a better prognosis when treatment is started promptly, at the beginning of the disease.

Ultrastructural identification of protein bodies, cellular markers of human catecholamine neurons, in a temporal lobe ganglioglioma.

A temporal lobe ganglioglioma, surgically removed from an 8-year-old body, and a human brainstem at the level of locus coeruleus (LC) were processed for light microscopy (LM), with formalin fixation and paraffin embedding, and for electron microscopy (EM) with glutaraldehyde fixation, potassium permanganate postfixation, phosphotungstic acid-hematoxylin block-staining, and epoxy-resin embedding. The paraffin sections were stained with toluidine blue O/rhodamine B and observed under epi-fluorescence. The thin sections for EM were viewed directly without further staining. The neuronal neoplastic cells of ganglioglioma and the neurons of LC are known to produce catecholamines. Both also contain spherical protein bodies (pb), cellular markers that identify catecholamine neurons in humans. The ultrastructural characteristics of the pb in LC were compared with those of the pb in neoplastic ganglion cells. These bodies had an identical ultrastructure, in both tissues, consisting of electron-lucent core surrounded by an electron-dense thin rim. The rhodamine B-stained sections also emphasized the identical morphology of the pb in ganglioglioma and LC. Based on the EM comparison, these brightly fluorescing spherical bodies are ideal markers for identifying in LM, the clusters of large neoplastic cells, representing neurons, which are the most important clue to the correct diagnosis of gangliogliomas.A temporal lobe ganglioglioma, surgically removed from an 8-year-old body, and a human brainstem at the level of locus coeruleus (LC) were processed for light microscopy (LM), with formalin fixation and paraffin embedding, and for electron microscopy (EM) with glutaraldehyde fixation, potassium permanganate postfixation, phosphotungstic acid-hematoxylin block-staining, and epoxy resin embedding. The paraffin sections were stained with toluidine blue O/rhodamine B and observed under epi-fluorescence. The thin sections for EM were viewed directly without further staining. The neuronal neoplastic cells of ganglioglioma and the neurons of LC are known to produce catecholamines. Both also contain spherical protein bodies (pb), cellular markers that identify catecholamine neurons in humans. The ultrastructural characteristics of the pb in LC were compared with those of the pb in neoplastic ganglion cells. These bodies had an identical ultrastructure, in both tissues, consisting of electron-lucent core surrounded by an electron-dense thin rim. The rhodamine B-stained sections also emphasized the identical morphology of the pb in ganglioglioma and LC. Based on the EM comparison, these brightly fluorescing spherical bodies are ideal markers for identifying in LM, the clusters of large neoplastic cells, representing neurons, which are the most important clue to the correct diagnosis of gangliogliomas.

Effects of reserpine and amphetamine on pteridine pattern and nuclear morphology of Triturus cristatus liver

Summary By means of paper chromatography and the Feulgen reaction the effects of reserpine and amphetamine on the pteridine pattern and nuclear morphology were studied in the liver of Triturus cristatus . It was demonstrated that the Feulgen stainability and state of aggregation of chromatin, as well as the pteridine pattern can be altered by the influence of these drugs. From the results obtained it is suggested that the observed changes in nuclear morphology are due to the interaction of the drugs with the pteridine metabolism.

Chromogranin A and Vesicular Monoamine Transporter 2 Immunolocalization in Protein Bodies of Human Locus Coeruleus Neurons

Abstract Our previous histochemical and ultrastructural studies have identified, in human catecholamine neurons, abundant spherical acidophilic protein bodies (pb), which originate from regular mitochondria, retaining their double membrane. In locus coeruleus (LC) neurons, pb have somatodendritic distribution and are unequivocal storage vesicles for noradrenaline, as demonstrated by immunolocalization of Dopamine-β-Hydroxylase. In the present study, in order to reinforce the identity of pb as monoamine storage sites in human LC, and to assess their potential of somatodendritic release, we studied the subcellular immunolocalization of chromogranin A (CgA) and vesicular monoamine transporter 2 (VMAT2), given the fact that their localization defines the vesicles capacity of filling with monoamine and hence exocytotic release. The data provided in the present study, demonstrate the novel ultrastructural immunolocalization of both CgA and VMAT2 in protein bodies, supporting their involvement in somatodendritic storage and release of noradrenaline in human LC. Since the molecular mechanism of LC somatodendritic exocytosis remains largely elusive, the present study may shed light to a better understanding of this mechanism.