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Biomedical subjects

P Mehraein

Publications and source records attributed to P Mehraein.

At least 55 records · Page 3Linked to original sources
PubMed1991

Striatopallidonigral degeneration in Pick's disease: a clinicopathological study of 41 cases.

The frequency and degree of stiatopallidonigral (SPN) degeneration were examined in 41 autopsy cases of Pick's disease. Based on the degree of SPN degeneration, these cases were arranged into four groups: 1) group I (severely degenerate; 19.5%), 2) group II (moderately degenerate; 22.0%), 3) group III (mildly degenerate; 36.5%), and 4) group IV (non-degenerate; 22.0%). 17 of the 41 cases had a definite (moderate to severe) SPN degeneration. The striatum, especially the caudate nucleus, was most frequently and most severely affected, while the internal segment of the globus pallidus was least frequently and least severely affected. In general, the oral portions of the SPN nuclei were more severely involved. In addition, in the putamen and globus pallidus the dorsomedial portions adjacent to the internal capsule were apt to be affected more markedly than the other portions. In the substantia nigra the degeneration tended to be more predominant in the pars reticulata than in the pars compacta, although both were usually involved. In addition, the medial to central portions of the substantia nigra were more vulnerable. In comparing the severely and moderately degenerate groups (groups I and II) with the mildly and non degenerate groups (groups III and IV), the former had more female cases, longer duration of illness, and more third-stage cases. In addition, the former contained more cases with lower brain weight and (predominant) frontal atrophy type, and more atypical cases without Pick bodies, or with symmetrical pyramidal tract degeneration or with combined traumatic lesions. It is notable that in all cases with definite SPN degeneration no extrapyramidal involuntary movements had been detected.

Adult↗
PubMed1990

Aneurysms and vacuolar degeneration of cerebral arteries in late-onset acid maltase deficiency.

We present a case of late-onset acid maltase deficiency (AMD) with pronounced involvement of the liver and skeletal muscles. In addition, and in contrast to other adult cases of AMD, the case presented here shows CNS pathology with hypodense and hyperintense white matter areas on CT and MRI scans, and myelin changes ranging from focal areas of demyelination to necrosis. Neuropathologic changes seem to be related to unusual vascular pathology consisting of vacuolar degeneration of small and large arterial blood vessels. Vacuoles of varying size, partly filled with granular PAS-positive material, were found in pericytes and smooth muscle cells of arterial vessel walls. Electron microscopy revealed lysosomal and cytoplasmic free glycogen in smooth muscle cells in the intima of large cerebral arteries as well as in pericytes of arterioles and capillaries. Accumulation of glycogen locally was associated with severe cellular damage and necrosis. The formation of a great number of small aneurysms of intracerebral arteries is thought to be the result of cell damage in the vessel walls.

Adult↗
PubMed1990

[Histopathology of the retina, optic fascicle and lateral geniculate body in chronic, bilateral symmetric ischemic Schnabel's cavernous optic atrophy].

The paper is a unique pathological description of a bilateral, symmetric, anterior, temporal ischemic optic neuropathy with the morphological characteristics of cavernous optic atrophy initially described by Schnabel in glaucomatous eyes. The 80-year-old woman had suffered from cardiac insufficiency and diabetes mellitus for many years. She died from sepsis and circulatory collapse due to ischemic colitis, intestinal perforation, and peritonitis. There was widespread arteriosclerosis but no evidence of giant-cell arteritis. Cell loss was demonstrated in both retinas, the chiasm, and in the central lateral geniculate body. These represent a retrograde, descending and ascending optic atrophy, with transsynaptic degeneration in the LGB. A small craniopharyngioma was found by chance in the infundibulum. Neither clinically nor morphologically were there any signs of glaucoma.

Aged↗
PubMed1990

[Striato-nigral degeneration (SND): a multisystem atrophy?].

Two cases of striato-nigral degeneration are reported. In case 1 the female patient showed a Parkinson syndrome, cardiac arrhythmias and vasomotor disturbances. Morphologically mainly the putamen and substantia nigra revealed severe atrophic changes according to the restricted form of striato-nigral degeneration (SND). In case 2 there was a disorder of the upper and lower motor neuron in a female patient. Morphologically this case was an example of a multisystem atrophy with changes in the striato-nigral, olivo-ponto-cerebellar systems and spinal motor and autonomic neurons. These cases demonstrate the variability of the striato-nigral degenerations which are met with in two forms: a "pure" form as in case one and as a part of multisystem atrophies. This is underlined in a review of 69 literature cases, which also shows that SND, Shy-Drager syndrome and olivo-ponto-cerebellar atrophy represent very probably different varieties of one and the same degenerative process.

Aged↗
PubMed1989

Beta-endorphin in the brainstem and the cerebellum of the human infant: regional levels' profile assessed with immunoaffinity chromatography and solid phase radioimmunoassay.

The regional levels' profile of human beta-endorphin (beta h-EP) was studied in the brainstem and the cerebellum of 16 infant victims of "Sudden Infant Death Syndrome" and other death causes. An immunoaffinity chromatography procedure based on a monoclonal antibody directed specifically against the N-terminus of beta-EP was used to extract this peptide from the tissue samples. Beta-EP was then assessed quantitatively by means of a very sensitive solid phase radioimmunoassay (using a polyclonal antibody specific for the C-terminus of beta-EP) developed especially for the study presented here.

Brain Stem↗
PubMed1989

Cerebral beta-endorphin levels in a woman with Prader-Labhart-Willi syndrome.

By means of a specific two-site immunoradiometric assay, we explored the beta-endorphin levels in various brain regions of a patient affected by Prader-Labhart-Willi Syndrome. The rank of the beta-endorphin levels of five cerebral zones (hypothalamus, substantia grisea centralis, pons dorsalis, medulla oblongata dorsalis medialis, thalamus medialis) of the patient was homologous to that of subjects without the syndrome, except for the medulla oblongata dorsalis medialis. In patient with the Prader-Labhart-Willi Syndrome this region had a higher ranking level than in subjects without it. However, a functional meaning cannot be attributed to such difference because the patient of this study did not exhibit neurological disturbances relating to elevated beta-endorphin levels in the medullary region investigated.

Adult↗
PubMed1987

Cerebral distribution of beta-lipotropin and beta-endorphin in infantile progressive spinal muscular atrophy of Werdnig and Hoffman disease.

The regional distribution's profile of beta-endorphin (beta-EP) and beta-lipotropin (beta-LPH) was determined in the brain of an infant who died from Werdnig-Hoffmann's disease. Regional levels of beta-endorphin-like immunoreactivity (beta-ELIR), resulting from beta-EP and beta-LPH, were generally low in comparison to the homologous levels found in victims dying of other diseases.

Brain Chemistry↗
PubMed1986

Growth inhibition of experimental glioma grafts by monoclonal antibody treatment.

The effects of 14AC1 monoclonal antibody (McAb) on 79FR-G-41 rat glioma cells in vitro, on the formation of metastases in lung by antibody coated glioma cells, and on the growth of glioma grafts in BALB/c-nu/nu mice were investigated. The 14AC1 antibodies - isotyped as IgG2a - were obtained from a hybridoma clone established after fusion of X63-Ag8.653 myeloma cells and spleen cells of BALB/c mice hyperimmunized with 79FR-G-41 glioma cells. Antibody treatment of glioma cells in vitro caused evident cell surface alterations and pronounced growth depression of most cells. However, a few tumor cells remained unchanged in morphology and continued to proliferate. Moreover, 14AC1 antibodies drastically reduced lung metastasis by pretreated and i.v. delivered glioma cells. Additionally, 14AC1 antibodies suppressed the growth of transplanted rat gliomas in nude mice as evidenced by a longer latency period and a smaller volume of glioma grafts in treated than in control tumor bearers. Nevertheless, glioma grafts showed accelerated growth after termination of antibody treatment. Further experimental investigation is required in order to identify the precise mechanisms of the effects of McAbs on tumor cells in vitro and in vivo.

Animals↗
PubMed1986

A quantitative study of the cerebral cortex in Alzheimer's disease and senile dementia using an automatic image analyzing system.

The gray level index method was used in order to quantitatively differentiate the histological characteristics of a pathological population (n = 14) from those of a normal population (n = 14). An automatic image analysis system compared the laminar patterns in the straight gyrus of the cerebral cortex of deceased normal patients with those who died with Alzheimer's disease and senile dementia. In comparison to the normal control group, the cases with Alzheimer's disease and senile dementia show a significant decrease in the gray level index of lamina III.

Aged↗
PubMed1985

Characterization of proenkephalin B-derived opioid peptides in the human hypothalamo-neurohypophyseal axis.

Proenkephalin B-derived opioid peptides, such as dynorphin1-17, dynorphin1-8, dynorphin B, alpha-neo-endorphin and beta-neo-endorphin in the human hypothalamo-neurohypophyseal tract were quantitated and characterized by the combined use of various radioimmunoassays, gel filtration, high performance liquid chromatography and enzymatic cleavage. Chromatographic analysis of immuno-reactive peptide levels determined that, in each case, these were comprised almost exclusively of the authentic peptides both in the neurohypophysis and hypothalamus. Concentrations of authentic proenkephalin B-peptides were 100-5000-fold lower in the human as compared to the rat neurohypophysis. However, in the paraventricular nucleus (PVN), supraoptic nucleus (SON) and certain other nuclei of the human hypothalamus concentrations of authentic peptides were found to be in the same range as those in the rat hypothalamus. The ratio of proenkephalin B-peptides in PVN and SON to those of the neurohypophysis in the rat was ca. 1:50. Conversely, in man these ratios were shown to be 80:1 for dynorphin B, 6:1 for alpha-neo-endorphin and 1:1 for all other peptides evaluated. Examination of postmortem degradation of peptides indicated that these lower levels in the neurohypophysis are not due to a higher rate of postmortem breakdown. Since levels of both vasopressin and beta-endorphin were very high, these deficits in proenkephalin B-peptides were selective and do not represent a generalized property of the human pituitary. Experiments involving enzymatic cleavage demonstrated the occurrence of higher molecular weight forms containing the Leu-enkephalin sequence which were not recognized by the antisera employed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Localization of experimental glioma grafts by means of iodinated monoclonal antibodies and radionuclide imaging.

Purified McAbs (14AC1) of IgG2a isotype raised against an experimental rat glioma (79FR-G-41) were labeled with Na131I and used for in vivo imaging of glioma grafts by external body scintigraphy. Normal mouse 131I-IgG was applied as control for non-specific uptake of proteins in the tumor. Nude mice bearing glioma grafts were injected i.v. with 15 micrograms of the 131I-McAb or 131I-IgG with an activity of approximately 150 microCi. Scans obtained 30 min, 24, 48, 72, and 96 h after injecting the intact 131I-14AC1 antibody demonstrated enrichment of radioactivity in the tumors. The tumors were clearly visible 48 h after injection of 131I-labeled antibody. The time course experiments showed that the uptake of 131I-14AC1 antibody in the glioma grafts was the result of specific antigen binding. Intact antibody provided adequate tumor visualization in the scintigrams without background subtraction. Therefore, this technique appears promising for in vivo tumor detection and may offer the possibility of improvement in the evaluation of diagnostic and therapeutic approaches to human gliomas.

Animals↗
PubMed1984

Distribution and characterization of opioid peptides derived from proenkephalin A in human and rat central nervous system.

In various areas of rat and human brain and spinal cord the distributions of opioid peptides derived from the proenkephalin A precursor, the heptapeptide [Met]enkephalin-Arg6-Phe7 (MERF), the octapeptide [Met]enkephalin-Arg6-Gly7-Leu8 (MERGL), and bovine adrenal medulla dodecapeptide (BAM-12P), were determined by a combination of radioimmunoassay, gel filtration, and high-performance liquid chromatography. In the human central nervous system the highest concentrations were seen in the striatum (pallidum greater than caudate nucleus greater than putamen) and in substantia nigra, hypothalamus, and periaqueductal gray. Similarly, in rat brain high levels were found in striatum and hypothalamus. Bovine adrenal medulladocosa peptide (BAM-22P) only occurred in the rat brain, but could not be detected in human brain. No MERF, MERGL, BAM-12P, or BAM-22P could be found in either rat or human pituitary. In contrast to MERF, MERGL and BAM-12P, peptides derived from the proenkephalin B precursor, dynorphin1-8 and dynorphin B, showed high concentrations only in substantia nigra and pallidum, but quite low levels in the other regions of human brain and spinal cord. The present study provides evidence that the proenkephalin A precursor known from adrenal medulla also exists in the rat and human central nervous system. Moreover, the identification of BAM-12P in these tissues indicates that cleavage of the precursor molecule must also involve sites different from those with paired basic amino acids.

Adolescent↗
PubMed1983

Proenkephalin-A-derived peptides are present in human brain.

The opioid peptides [Met] enkephalin-Arg6-Phe7, [Met]-enkephalin-Arg6-Gly7-Leu8, and BAM-12P were identified in various ares of human brain by use of a combination of radioimmunoassay (RIA), gel filtration, and high performance liquid chromatography (HPLC). The highest levels of each peptide were found in striatum, followed by substantia nigra, hypothalamus, and medulla. In all areas, the relative concentrations were [Met] enkephalin-Arg6-Phe7 less than [Met] enkephalin-Arg6-Gly7-Leu8 less than BAM-12P. The apparent existence of BAM-12P suggests that the enzymatic processing of the proenkephalin A precursor in human brain is not restricted to cleavage at sites with two basic amino acids. Our results provide evidence that a precursor similar or identical to that present in the adrenal medulla exists in human brain. It appears that the processing mechanisms are different, as virtually none of the immunoreactivity found in the brain was comprised of the higher molecular weight forms of the peptides seen in the adrenal.

Brain Chemistry↗
PubMed1982

Opiate receptor binding sites in human brain.

Subclasses of opiate receptor binding sites in human brain membranes were investigated by means of competitive binding techniques. The experimental data were analyzed by use of a computerized non-linear regression curve fitting program. mu-, delta-and chi-types of opiate binding were found in 5 different regions of the brain. A more extensive analysis of the regional distribution of subclasses of opiate binding sites was performed using a simple sequential inhibition technique. This method was shown to yield results which are comparable to those obtained by computer analysis of multiple tracer displacement curves. Chi-and mu-sites represented the major component of binding in most brain areas whereas delta-sites were fewer in number. The 3 types of binding showed different distribution patterns, suggesting that they are independent from each other. The distribution pattern observed in human brain resembled the one observed in rat brain, although chi-sites appear to represent a more important, and delta-sites appear to represent a less important, fraction of binding in human as compared to rat brain.

Adolescent↗
PubMed1982

Immunoreactive dynorphin in human brain and pituitary.

The distribution of immunoreactive dynorphin (ir-dyn) has been determined in various regions of human brain and pituitary by use of a highly specific radioimmunoassay. The concentrations of ir-dyn in the substantia nigra (24.5 pmol/g) and hypothalamus were among the highest in the 26 brain areas examined. Substantial amounts were also measurable in other extrapyramidal structures such as the caudate nucleus, pallidus and putamen. Lower concentrations of ir-dyn were detected in the amygdala, hippocampus, periaqueductal gray matter, colliculi, pons, medulla and area postrema, but only low amounts were found in the posterior lobe of the pituitary, while no ir-dyn was detectable in the anterior lobe. By gel permeation chromatography the brain immunoreactivity was shown to consist of 3-4 peaks of apparent molecular weights of about 12,000, 6000, 1800 and less than 1000. It was possible to demonstrate the high opioid potency of 2 of these peaks in the guinea-pig ileum longitudinal muscle bioassay after purification by immunoprecipitation. A comparison of the distribution pattern of ir-dyn revealed some parallels with enkephalin, whereas the distribution of ir-beta-endorphin is quite different.

Adult↗