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Biomedical subjects

L Horvath

Publications and source records attributed to L Horvath.

At least 19 recordsLinked to original sources
PubMed1992

Precipitation and characterization of an aluminosilicate from AlCl3-Na2SiO3-HCl in serum, of interest for Alzheimer disease.

A precipitation experiment was performed with human serum to model aluminosilicate formation in brains of patients with Alzheimer disease. Aluminum and (or) silicate ions were added to serum in a 1:2 molar ratio at pH 7.4. Precipitates formed immediately and were left for 24 h at 37 degrees C before filtration. Silicate and aluminosilicate formed precipitates with human serum proteins albumin, transferrin, and IgG. In untreated samples, the IgG/albumin ratio increased slightly compared with the ratio in dried serum. Diethylbarbiturate-washed precipitates had a significantly lower protein content than did untreated ones. The IgG/albumin ratio increased considerably in the sample containing aluminosilicate. We conclude that IgG is the sodium dodecyl sulfate-soluble human protein most firmly bound to the aluminosilicate matrix. From 27Al magic-angle-spinning nuclear magnetic resonance (MAS NMR), a pronounced peak was found at 52.79 ppm and a minor peak at 0.53 ppm, suggesting that 4-coordinated aluminum predominates and that 6-coordinated aluminum is present in a smaller proportion. The 29Si MAS NMR spectrum shows a poorly ordered structure. The aluminosilicate formed also contains the cations Na+ > K+ > Ca2+ > Mg2+ and anions Cl- > PO4(3-). Rather than looking for aluminum toxicity to explain the effects of Alzheimer disease, one should consider that by precipitating such a composite phase, the balance of cations, anions, and proteins in human serum is changing.

Aluminum↗
PubMed1990

Oxalate molecule as the trap for gamma-irradiation energy in the amorphous aluminosilicate Al2(OH)6H4SiO4.

Paramagnetic species which were the products of gamma irradiation at 77 K and at room temperature were studied by ESR spectroscopy in the amorphous aluminosilicate, Al2(OH)6H4SiO4, prepared in the presence and in the absence of oxalate ion. The aluminosilicate precipitated from the solution containing the oxalate ion in 10(-4) mol dm-3 concentration contained the oxalate only in trace amounts. When gamma-irradiated at 77 K and at room temperature, this compound gave the stable paramagnetic species represented by the single ESR line centered at g = 2.000. We ascribe this spectrum to the CO2- radical formed from the oxalate ion. The same aluminosilicate prepared in the absence of the oxalate either produced no stable paramagnetic product after gamma irradiation at room temperature or resulted in composite ESR spectra, indicating the presence of several paramagnetic species if irradiated at 77 K. Complex ESR spectra were transformed by heating to the stable paramagnetic centers which differed from the one obtained from oxalate ion. We conclude that in Al2(OH)6H4SiO4 oxalate acts as a trap for the gamma-radiation energy.

Aluminum Silicates↗
PubMed1989

Temporary arrest of fetal movement with pancuronium bromide to enable antenatal magnetic resonance imaging of holoprosencephaly.

The well-known ability of real-time ultrasound to detect congenital abnormalities is often limited by acoustic artifact or fetal position or both. Magnetic resonance imaging can provide superior soft tissue resolution but is vulnerable to maternal and fetal motion artifact. Described and illustrated here is a case of fetal holoprosencephaly that was not of diagnostic clarity on ultrasound. The fetus was paralyzed with an intramuscular injection of pancuronium bromide before a resonance imaging study. Successful fetal paralysis with pancuronium bromide has been reported prior to a variety of fetal interventions for the temporary arrest of fetal movement. The resonance study illustrated here was of significantly superior clarity and improved the accuracy of prognosis and management counseling. It is concluded that in selected cases where ultrasound is not of diagnostic clarity due to acoustic artifact, fetal paralysis and magnetic resonance imaging may be considered.

Abnormalities, Multiple↗
PubMed1981

Detection of antibodies to myelin basic protein by solid-phase radioimmunoassay with [125I]protein A.

A solid phase radioimmunoassay (RIA) for the detection of antibodies to myelin basic protein (MBP) in sera has been developed employing MBP-coated flexible polyvinylchloride microtiter trays and [125I]protein-A as the radiolabel. [125I]Protein-A directly binds to the Fc region of serum IgG from several animal species and serves as an excellent reagent for detecting antibody. It can also be used to bind to a second antibody ligand, thereby making it useful even when it does not bind directly to the primary antibody Fc region. The use of one preparation of [125I]protein-A label allows sera from several species to be tested for antibodies to MBP simultaneously, thereby making this RIA technically simple, rapid and economical. This assay has been particularly useful in examining serum samples from animals with experimental autoimmune encephalomyelitis and hypomyelinogenisis congenita. In patients with multiple sclerosis low levels of antibody to MBP can be detected in cerebrospinal fluid (CSF) and acid-eluted extracts from brain plaque material; detection of low levels of antibody in human serum has not been possible due to non-specific binding of human serum Ig in this RIA.

Animals↗
PubMed1979

Radiometric assessment of experimental autoimmune encephalomyelitis in mice.

The cell-mediated inflammatory component of experimental autoimmune encephalomyelitis (EAE) in mice is measured by the radioisotopic technique. Mice are challenged with autologous spinal cord homogenate in Freund's complete adjuvant and at various time intervals after such immunization given [125I]5-iodo-2'-deoxyuridine which is incorporated into the mononuclear cell pool. The degree of cell-mediated inflammation is determined by radiometry of the brain and spinal cord tissues. Increased radiolabelling is detected in the brains 2 days prior to the onset of clinical signs of EAE; increased radioactivity of the spinal cord is concomitant with clinical signs. This technique is useful in staging the extent of EAE and may prove to be a powerful tool in studying cell-mediated reactions in other autoimmune diseases.

Animals↗
PubMed1978

A search for the "multiple sclerosis virus"--lack of effect of brain extracts on myelin development in chickens, mice and rats.

Attempts were made to transmit possible infectious agents from tissue of MS patients into three animal species, under conditions designed to enhance the development of such an agent. Myelination was monitored by measuring CNPase activity and myelin basic protein. Although no significant effects were observed, the usefulness of a new assay for CNPase was demonstrated. Nude mice were found to have a lower level of CNPase than their heterozygous littermates.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1977

Spinal dissemination following operation on cerebral oligodendroglioma.

This paper concerns two cases of cerebral oligodendroglioma (intraventricular in one case, right temporal in the other), with spinal dissemination (cervical and upper thoracic respectively), manifested clinically 2 years and 14 months respectively after removal of the cerebral tumour. Anatomical examination confirmed the diagnosis of disseminated oligodendroglioma in the leptomeninges in both cases and also in the parenchyma in the second case.

Adult↗
PubMed1976

Encephalopathy subsequent to accidental poisoning with chlorpromazine.

A cerebral biopsy performed in an infant 9 months after accidental poisoning with chlorpromazine was studied. Light microscopy disclosed necrosing encephalopathy, while electron microscopy showed neuronal, glial, myelinic and vascular lesions. The findings in the present study suggest that the various neurologic syndromes appearing in cases of prolonged treatment with neuroleptic drugs and persisting after cessation of therapy would be due to consequent occurrence, in specific areas, of some irreversible cerebral lesions.

Capillaries↗
PubMed1975

Intracranial ganglioneuromas in children.

Two cases of tumours of the sellar and suprasellar region in children, manifested clinically by visual and endocrine disturbances, are reported. In both cases surgical removal of the intracranial tumour was performed. The histological diagnosis was central ganglioneuroma, an extremely rare tumour in children. Also worthy of note was the altogether exceptional location in these children of central ganglioneuromas in the sellar and suprasellar region.

Brain Neoplasms↗
PubMed1975

Giant cell tumors of the calvaria.

The authors report and discuss four rare cases of primary, giant cell tumor of the cranial vault, a usually benign tumor that develops in young patients and has an extremely low rate of latent malignancy. The authors believe the preferred treatment to be total surgical removal of the tumor; only in rare cases of malignancy when the tumor is impossible to remove totally should this be combined with radiotherapy. Associated minor trauma played only a tumor-revealing role and was not involved in the etiology.

Adult↗
PubMed1972

Cloverleaf skull.

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Cerebral Angiography↗