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M Mazzuca

Publications and source records attributed to M Mazzuca.

At least 37 records · Page 2Linked to original sources
PubMed1991

The immunohistochemical evidence of amyloid diffuse deposits as a pathological hallmark in Alzheimer's disease.

We performed an immunocytochemical study of cerebral cortex from cases of Alzheimer's disease and from aged nondemented controls, using periodic acid pretreatment and polyclonal beta-protein antibodies. In addition to senile plaques (SP) and amyloid angiopathy (AA), the beta-protein antibodies detected band-like deposits present throughout the cortical layers. Moreover, large plaque-like infiltrations with diffuse and amorphous characteristics were observed in the cortical gray and white matter, and these deposits were often associated with capillaries. Our results suggest that an abundance of these lesions, which were detected only with this immunostaining procedure in Alzheimer cortex, may be characteristic of Alzheimer's disease.

Aged↗
PubMed1991

Evidence for different human tracheobronchial mucin peptides deduced from nucleotide cDNA sequences.

Highly glycosylated regions or glycopeptides were obtained by proteolysis of human tracheobronchial mucins. They were chemically deglycosylated and the resulting products were used to raise a rabbit antiserum. This antiserum specifically recognized the superanuclear region of respiratory and colonic goblet cells as areas around and below the nucleus of mucin-secreting cells in tracheobronchial mucous glands. A lambda gt11 cDNA library constructed from human tracheobronchial mucosa was screened with this antiserum. Ten positive clones were obtained from screening half of the library (about 10(6) recombinants). The antibodies were purified by absorption to each positive clone; some purified antibodies were specific for goblet cells and others recognized both goblet and mucous cells, indicating that there is differential cellular expression of mucin peptides. The total or partial amino acid sequences deduced from these cDNA clones could be classified into three groups. The first group contained repetitive sequences of eight amino acid residues, almost perfectly identical, and in different arrangements. The second type exhibited homology at their amino and carboxy-terminal ends. The last group had no distinctive feature except for a high content of hydroxy amino acids typical of mucins. Five different clones could correspond to the carboxy-terminal end of tracheobronchial apomucins. These results indicate that human tracheobronchial apomucins consist of a family of different proteins.

Amino Acid Sequence↗
PubMed1990

Effects of inhibition of GABA catabolism by aminooxyacetic acid on enkephalinergic neurons--immunocytochemical and ultrastructural study in the enkephalinergic hypothalamoseptal tract of the guinea-pig.

The immunocytochemical and ultrastructural features within [Met]enkephalin neurons of the guinea-pig hypothalamoseptal tract were investigated under chronic inhibition of GABAergic catabolism. This was achieved by raising the brain GABA concentration with aminooxyacetic acid which inhibits GABA-transaminase, the enzyme responsible for the catabolism of GABA. Guinea-pigs were injected intraperitoneally with 10 or 20 mg/kg per day aminooxyacetic acid for two, four or eight days and killed 16 h post-dose. Repeated injections of aminooxyacetic acid produced a great increase in immunoreactivity for GABA in nerve endings surrounding enkephalinergic perikarya in the magnocellular dorsal nucleus of the guinea-pig. Extensive immunocytochemical studies stressed the increase and redistribution of the immunoreaction for [Met]enkephalin in the perikarya of the magnocellular dorsal nucleus under such GABAergic activation. Quantitative and statistical analyses showed that administration of aminooxyacetic acid for eight days significantly increased the intensity of labelling within stimulated perikarya (P less than 0.001). A concomitant accumulation of immunopositive large granules in the enkephalinergic boutons of the lateral septum was observed. In the same way, ultrastructural changes in enkephalinergic cell bodies were analysed and reflected disturbances in the biosynthetic and digestive activities of enkephalinergic perikarya. We postulate that chronic inhibition of the GABAergic catabolism leads to modification in the metabolism of enkephalinergic neurons and to an inhibitory action of GABA on the [Met]enkephalin release from nerve endings. This study give morphological support to the complex functional interactions between GABA and opioid peptide transmitter system.

Aminooxyacetic Acid↗
PubMed1990

[Alzheimer's disease: the beta amyloid protein A4 is also present in the cortical white matter].

Amyloid deposits constituted with the beta amyloid protein A4 (beta PA4) have been recently immunodetected in skin and intestine wall of Alzheimer's patients. These findings support the hypothesis of an extraneuronal origin of the beta PA4. Until now, these amyloid deposits had not been observed in the white matter of Alzheimer's brains. Using an antiserum against the 1-10 N Ter subsequence of the beta PA4, we immunodetected amyloid deposits in white matter sections of Alzheimer's brains, pretreated with periodic acid. The immunolabelled amyloid substance was associated with capillaries. These original findings are in good agreement with the vascular origin of the beta PA4.

Aged↗
PubMed1990

[Gonadotropic adenoma. Clinical and hormonal characteristics].

The main clinical and hormonal features of gonadotropin secreting adenomas (GSA) are reviewed through the literature and our personal data. There is still no agreement about their definition and frequency. The most classical clinical presentation is that of men aged 50 years or more, bearing a large pituitary adenoma, the only biological expression of which is a moderately elevated serum FSH level. Female cases are less recognised and are underestimated because the serum LH and/or FSH elevated levels are not informative in menopausal women. The assay of the alpha subunit may help in these cases. In premenopausal women, few of them having been described so far, the GSA may be revealed by an amenorrhea-galactorrhea syndrome with a mild hyperprolactinaemia which may result from different mechanisms. The absence of gonadal hyperactivity, and, conversely, the frequent hypogonadism associated with GSA lead the clinician to raise some questions: are all GSA able to secret gonadotropins? How is the bioactivity of the LH and/or FSH secreted by GSA? How reliable are the radioimmunoassays routinely used for measurement of LH and FSH in patient's serum? Furthermore, therapeutical management of GSA is still impaired by the lack of documented medical treatments which could control their growth and prevent their recurrence.

Adenoma↗
PubMed1989

Dystrophic peptidergic neurites in senile plaques of Alzheimer's disease hippocampus precede formation of paired helical filaments.

The relationship between peptidergic dystrophic neurites and paired helical filament (PHF)-positive neurites in Alzheimer's disease (AD) senile plaques (SPs) was studied using combined fluorescence and bright-field optics. Cryostat sections of AD hippocampi were first stained with thioflavine-S and immunolabelled with antisera raised against different neuropeptides: somatostatin-28(1-12), somatostatin-14, neuropeptide Y, cholecystokinin (CCK) and substance P. Secondly, using the elution-restaining procedure, sections were immunolabelled with anti-tau/PHF. In immature SPs, clusters of abnormal, swollen neurites were found. The dystrophic, strongly peptidic-positive neurites contained fewer PHFs than the poorly positive ones. Cell bodies, exhibiting a peptidic content, could be found within SPs without any alteration. These results suggest the following sequence of events: an extracellular poisoning mechanism, perhaps the amyloid substance, first changes the structure of presynaptic endings and causes the formation of ballooning dystrophic neurites filled with their normal peptidic content. Subsequently, intracellular degradation occurs with formation of the PHFs. Then the other structures such as dendrites and perikarya are damaged by the same mechanism. Therefore, this phenomenon seems to precede any formation of PHFs in SPs.

Alzheimer Disease↗
PubMed1989

An antiserum to the N-terminal subsequence of the Alzheimer amyloid beta protein does not react with neurofibrillary tangles.

Polyclonal antibodies were raised against a synthetic peptide corresponding to a subsequence for the first 10 residues of the beta amyloid protein A4 (1-10 beta PA4). In an immunoperoxidase study of Alzheimer brain tissue, these antibodies immunostained senile plaque cores, amyloid vessel walls, and amyloid fibrils surrounding senile plaques and angiopathic vessels. Neurofibrillary tangles stained with thioflavin S or immunostained with anti-Tau immune serum were never immunodetected with the anti 1-10 beta PA4. We confirm that the neurofibrillary tangles do not contain epitopes corresponding to the first 10 residues of the beta PA4.

Alzheimer Disease↗
PubMed1989

Use of an antiserum against deglycosylated human mucins for cellular localization of their peptide precursors: antigenic similarities between bronchial and intestinal mucins.

Highly glycosylated regions of mucins, or glycopeptides, were obtained by proteolysis of human bronchial mucins. They were deglycosylated by treatment with a trifluoromethane sulfonic acid/anisole mixture and subsequent solvolysis with anhydrous liquid hydrogen fluoride. The resulting peptides were then used to raise an immune serum in rabbit. This immune serum was used to localize the peptide precursors of human respiratory mucins within bronchial cells, using an immunohistochemical method. Two main patterns of labeling were observed in the goblet cells: the entire cytoplasm of some goblet cells was immunoreactive, whereas in other cells the labeling was concentrated around the nucleus. In the respiratory mucous glands, the labeling was localized around or below the nucleus. The serous cells were not stained. Similar labeling was observed in human colon goblet cells. This immune serum seems to be specific for mucin-secreting cells and has a strong affinity for the perinuclear region of these cells.

Amino Acids↗
PubMed1989

Alzheimer's disease: glycolytic pretreatment dramatically enhances immunolabeling of senile plaques and cerebrovascular amyloid substance.

In Alzheimer's disease, three types of pathologic lesions are stained by thioflavin: neurofibrillary tangles, senile plaques, and amyloidaceous vessels. We have used anti-beta protein amyloid A4 and anti-tau protein antisera and compared immunolabeling with thioflavin staining. Anti-tau detected only neurofibrillary tangles; anti-beta-PA4 immunostained senile plaques and amyloidaceous vessels. Glycolytic pretreatment (2% periodic acid overnight or glycosidases digestion) dramatically enhanced the anti-beta-PA4 immunolabeling of senile plaques, amyloidaceous vessels, and a previously undetected extracellular substance; neurofibrillary tangles were never immunostained. Therefore, glycolytic pretreatment exposes buried epitopes in the amyloid and is a good method for amplification of immunostaining. The nature of the interaction between saccharides and beta-protein amyloid A4 is unknown.

Alzheimer Disease↗
PubMed1989

[Alzheimer's disease: immunohistochemical characterization of cerebral amyloid deposits].

In Alzheimer cortex tissue sections, thioflavine stained three patterns of amyloid lesions: neurofibrillary tangles (NFT), senile plaques (SP) and vessel walls (amyloid angiopathy AA). An anti serum against Tau proteins detected NFT but neither SP nor AA. In contrast, an anti serum against beta protein amyloid (BP A4) revealed SP and AA but not NFT. A periodic acid pretreatment dramatically enhanced the anti-BP A4 immunolabelling corresponding to microplaques as well as a large amount of diffuse extracellular amyloid substance, but never stained NFT. Pretreatment of tissue sections with a mixture of endo and exoglycosidases gave identical results and corroborates the extraneuronal processing of BP A4 that appears in a glycosylated form in the extracellular compartment.

Alzheimer Disease↗
PubMed1989

[New elements in the diagnosis and treatment of thyrotropic pituitary adenomas with hyperthyroidism].

Although thyrotropin-secreting pituitary tumors are rather exceptional, the authors have studied 5 new cases from 1982 to 1988. This apparently growing pattern is due to a more accurate diagnosis because of new laboratory measurements: --Immunoradiometric assay (IRMA) of ultra-sensitive thyrotropin (TSH); --Radioimmunoassay (RIA) of free alpha subunit of TSH; --Molar ratio of free alpha subunit/TSH before and after TRH stimulation; --Morphologic assessment of pituitary adenoma by computed tomographic scanning and nuclear magnetic resonance imaging; --Characterization of thyrotropin-secreting cells by immunohistochemical technics and identification of secretion products in cultured cells. The authors illustrate these new topics with a case report harboring a partial resistance to thyroid hormones. A 6-month treatment with somatostatin analogue (SMS 201.995) is reported, before transphenoidal ablation of the adenoma.

Adenoma↗
PubMed1988

GABA axon terminals in synaptic contact with enkephalin neurons in the hypothalamus of the guinea pig. Demonstration by double immunocytochemistry.

By using a method combining pre-embedding immunoperoxidase staining for enkephalin and postembedding immunocolloidal gold labeling for gamma-aminobutyric acid (GABA) it has been demonstrate that many GABAergic boutons made synapses on enkephalin-reacting soma in the magnocellular dorsal nucleus of the guinea pig hypothalamus. The gold particles revealing the presence of GABA were essentially located over the small clear vesicles and mitochondria present in these GABAergic nerve endings. All the synapses observed were symmetrical. Taking into account the great number of these nerve endings, we conclude for a strong regulatory role of GABA on enkephalin-containing cells of the magnocellular dorsal nucleus.

Animals↗
PubMed1988

Alzheimer's disease: a new evidence for common epitopes between microtubule associated protein Tau and paired helical filaments (PHF): demonstration at the electron microscope level by a double immunogold labelling.

Paired helical filaments (PHF) are neuronal landmarks of Alzheimer's disease. These pathological filaments are antigenically related to proteins present in the normal cytoskeleton, particularly to microtubule associated protein Tau. The evidence for these common epitopes was studied on sections of cortex from Alzheimer brains after Araldite embedding. Two rabbit immune sera were used: one was raised against PHF isolated from Alzheimer cortex; the other against Tau proteins extracted from bovine cortex. The comparison of adjacent semi-thin sections alternatively treated with anti-PHF and anti-Tau immune sera reveals that both stained degenerating neurofibrils in pyramidal perikarya and in neurites surrounding senile plaques. On ultra-thin sections, double immunogold labelling of PHF was obtained. These results are in accordance with the hypothesis that Tau proteins are major antigenic components of PHF.

Alzheimer Disease↗
PubMed1988

Cortical angiopathy in Alzheimer's disease: the formation of dystrophic perivascular neurites is related to the exudation of amyloid fibrils from the pathological vessels.

We studied the organization of dystrophic neurites around pathological vessels in Alzheimer cortex. Two techniques were used simultaneously on serial sections: thioflavine staining of amyloid substance and immunohistochemistry with immune sera against Paired Helical Filaments (anti-PHF) and native Tau proteins (anti-Tau). We observed different distributions of dystrophic neurites (immunolabelled with anti-PHF or anti-Tau) around thioflavine-stained angiopathic arterioles. The wall of the vessels with large diameter (greater than 100 microns) presented a congophilic angiopathy without neuropil reaction. In vessels with lesser diameter (less than 100 microns), dystrophic neurites constituted a discontinuous sleeve around vessels, always in close contact with amyloid substance outside the wall (dysphoric angiopathy). We observed structures similar to senile plaques around capillaries (diameter: 10-15 microns). The sleeve of dystrophic neurites with aggregated Tau proteins were always observed in the close vicinity of the amyloid substance which exuded from the pathological blood vessels. Thus, the exudation of these amyloid fibrils seems to induce the formation of dystrophic neurites (neuritic reaction).

Aged↗
PubMed1988

Catecholamine innervation of enkephalinergic neurons in guinea pig hypothalamus: demonstration by an in vitro autoradiographic technique combined with a post-embedding immunogold method.

To study the relationship between the catecholamine (CA) nerve endings and the enkephalinergic cell bodies in the magnocellular dorsal nucleus (MDN) of guinea pig hypothalamus, double-labeling experiments were performed on the same tissue section at the electron microscopic level. An in vitro autoradiographic (ARG) method for [3H]-norepinephrine (NE) or [3H]-dopamine (DA) was combined with a post-embedding immunogold cytochemical technique for Met-enkephalin (Met-enk) in colchicine-treated animals. Hypothalamic slices (450 micrograms) were perfused with [3H]-NE or [3H]-DA at the fluid-gas interface, then fixed by immersion with glutaraldehyde and osmic acid. Semi-thin sections processed from the thickness of the slices showed adequate penetration of the tracers to all parts of the tissue. Frontal sections permitted visualization of some CA-uptake structures distributed around the cells. At the ultrastructural level, preservation appeared good on about 60% of the thickness of slices, and [3H]-CA structures were easily distinguished. Ultra-thin sections were successively incubated with Met-enk and colloidal gold-labeled antisera, followed by ARG processing. At the electron microscopic level, the good integrity of the tissue made possible visualization of [3H]-CA nerve terminals making synaptic contacts with enkephalinergic perikarya. These results provide morphological evidence for direct catecholaminergic control of enkephalinergic neurons of the MDN.

Animals↗