Masaji Murakami

Immunohistochemical localization of apolipoprotein E in human glial neoplasms.

Immunocytochemical analyses revealed the presence and distribution of apolipoprotein E (apo E) in normal human brain tissue as well as in 77 human intracranial neoplasms. In normal brain tissues, the perikarya of astrocytes exhibited a strong positive reaction, whereas the Bergmann glia were stained to a moderate degree. However, no immunoreactivity was observed with neurons, oligodendrocytes, ependymal cells, and choroidal epithelium. Among the intracranial neoplasms, oligodendroglioma, choroid plexus papilloma, hemangioblastoma, primary malignant lymphoma, neurinoma, meningioma, pituitary adenoma, and craniopharyngioma were all negative. Immunoreactivity in the peripheral neuroblastoma was nil. However, the perikarya of astrocytomas and glioblastomas showed a positive reaction. Analyses on the degree of anaplasia and the amount of apo-E as an intensity of immunostaining showed a negative correlation. The astrocytic elements were stained in mixed oligoastrocytomas and medulloblastomas with glial differentiation. A few cases of ependymomas showed weak perikaryal immunostaining. Western blot analyses with anti-apo E antibody of a freshly prepared surgical specimen with astrocytomas revealed a single band with a molecular weight of approximately 37,000. The well differentiated cultured human astrocytoma cells secreted apo E into the medium. These lines of evidence suggest that apo E may serve as a potential marker specific for astrocytomas and glioblastomas, as well as an indicator of astrocytic tumor cell differentiation. The apo E localization in human brain tumors could be clinically relevant and diagnostically useful.

Age- and sex-related differences in lipoproteins containing apoprotein A-I.

We Investigated ageand sex-related differences In the structure and composition of two species of lipoproteins that contain apoprotein (apo) A-I (A-I Lp): lipoproteins containing apo A-I and apo A-II (Lp A-l/A-ll), and Iipoprotein containing apo A-I but no apo A-II (Lp A-I), which were isolated by immunoaffinlty chromatography. Sixty normollpidemlc volunteers were assigned to one of three groups based on their ages and sexual maturation (Group A, prepubertal; Group B, puberty; and Group C, postpuberty). In A-I Lp, the levels of total cholesterol, choiesteryi ester, phosphoiipid, and apo A-I were lower In males during puberty and then remained stable. In Lp A-I/ A-II, there were no ageor sex-related changes In llpids or In apo A-II. Levels of apo A-I in the females were lower with advance in age, although significant differences were observed only between preand postpubertal subjects. In Lp A-I, the levels of total cholesterol, choiesteryi ester, phosphoiipid, and apo A-I were lower In males during puberty and remained stable thereafter, as in the case of A-I Lp. Therefore, the ageand sex-related differences observed in A-I Lp appear to be primarily due to the differences In Lp A-I. When we take Into account the constancy of Lp A-l/A-ll levels In all groups, the physiological function of A-I Lp (high density Iipoprotein) In each Individual may be limited by the Lp A-I levels.

Primary intracranial plasma-cell granuloma: a case report and review of the literature.

BACKGROUND Plasma-cell granulomas, which are characterized by the non-neoplastic proliferation of plasma cells, are primarily found in the lungs and upper respiratory tracts, and are extremely rare in the central nervous system. METHODS An intracranial tumor of an 11-year-old boy was evaluated by histologic and radiologic examination. RESULTS An 11-year-old boy had a 2-month history of mild headache and nausea. A computed tomography scan showed a round, slightly high-density mass surrounded by marked edema in the left frontal lobe. On magnetic resonance imaging (MRI), the mass had a slightly high signal intensity on the T1-weighted image and marked low signal intensity on the T2-weighted image. It was heterogenously enhanced with gadolinium-DTPA. Microscopic examination demonstrated a non-neoplastic mixed cell population with a predominance of plasma cells. Immunohistochemical staining revealed that it was characterized by a polyclonal plasma cell population. CONCLUSION Our extensive search of the literature indicated this to be the ninth reported case of intracranial plasma cell granulation. The MRI was very useful for evaluating the extent of the intracranial lesions. The tumor was removed surgically and did not recur during a 2-year follow-up with no radiation therapy.

Acetylated low-density lipoprotein is endocytosed through coated pits by rat peritoneal macrophages

SummaryThe surface distribution of the scavenger receptors for acetylated low-density lipoprotein (acetyl-LDL) and their endocytic behavior were studied by the direct immunoperoxidase method using monomeric conjugates of horseradish peroxidase with Fab’ antibody raised against LDL. The receptors were demonstrated to be distributed diffusely on the surface membrane of cultured peritoneal macrophages, with preferential localization in coated pit regions. With temperature shift from 4° C to 37° C, acetyl-LDL bound to the surface membrane rapidly disappeared, but became detectable in coated vesicles or lysosomes. Further incubation in the presence of acetyl-LDL revealed lipid vacuoles devoid of a limiting membrane in the cytoplasm, transforming macrophages into typical foam cells. These data suggest that the binding of acetyl-LDL to its receptors triggers the clustering of the receptors into the coated pit regions through which acetyl-LDL is endocytosed by coated vesicles to be degraded in lysosomes with subsequent intracellular accumulation of cholesterol esters.

Hemangioma of the temporalis muscle: Case report and review of the literature

A 51 year-old man presented with a 10-year history of a painless, slowly growing mass (35 x 25 x 15 min) in the right temporal fossa. The T1-weighted image on magnetic resonance imaging demonstrated a partial, low-signal intensity lesion with high intensity in the lower part and significant enhancement with contrast medium. The tumor, which lay within the temporal muscle, was totally excised, and histological examination confirmed the lesion to be an intramuscular, cavernous type of hemangioma. The therapeutic options are described.

Isolated oculomotor nerve palsy following midbrain infarction

A 62 year-old male patient presented with isolated oculomotor nerve palsy following a small infarction of the medial ventral midbrain, documented by magnetic resonance imaging. There was a 12-year history of hypertension, but no diabetes mellitus. Angiography revealed atherosclerosis of the paramedian mesencephalic arteries. Magnetic resonance imaging may be useful in patients with small brain stem infarctions.

Isolation of apolipoprotein A-I-containing lipoproteins by immunoaffinity chromatography using a formylated derivative of cellulose gel

Immunoaffinity chromatography is an important tool used to purify the single component from the mixture such as plasma. In the present study, we designed a simple and efficient method for isolating lipoproteins by anti-APO A-I and Apo A-II immunoaffinity columns using Formyl-Cellufine gel. With the combination of these two columns, we quantitated two different species of Apo A-I containing lipoproteins; lipoprotein containing Apo A-I and Apo A-II (LpA-I/A-II), and lipoprotein containing Apo A-I but no Apo A-II (LpA-I). To compare the present method with the conventional one which makes use of cyanogen bromide activated agarose, we also tested anti-APO A-I and anti-APO A-II immunoaffinity columns, using a CNBr-activated agarose gel.

Scavenger receptor for malondialdehyde-modified high density lipoprotein on rat sinusoidal liver cells

We report here the presence of a membrane-associated receptor which mediates endocytic uptake of malondialdehyde-modified high density lipoprotein (MDA-HDL) on sinusoidal liver cells. Binding of [125I]MDA-HDL to the cells was followed by internalization and degradation in lysosomes. The binding and lysosomal degradation of [125I]MDA-HDL were effectively inhibited by unlabeled MDA-HDL and acetyl-HDL. However, formaldehyde-treated serum albumin or low density lipoprotein modified either by acetylation or malondialdehyde, ligands known to undergo receptor-mediated endocytosis by sinusoidal liver cells, did not affect the binding of [125I]MDA-HDL to the cells. These results indicate that a receptor for MDA-HDL is described as a distinct member among the scavenger receptors for chemically modified proteins.

Paradoxical Worsening of Spasticity and Pain in the Lower Extremities After Increasing the Dose of Intrathecal Baclofen—Case Report

Objectives:  Some patients with spasticity and pain in the extremities fail to respond to increases in the dose of intrathecally delivered baclofen.

Receptor-mediated endocytosis of aldehyde-modified proteins by sinusoidal liver cells

Formaldehyde-treated serum albumin (f-Alb) is known to be endocytosed by sinusoidal lever cells via a receptor-mediated mechanism. The receptor purified from rat livers exhibited a molecular weight of 125,000, consisting of two glycoprotein components with molecular weights of 53,000 and 30,000, respectively. Experiments using antireceptor antibody demonstrated that the f-Alb receptor is distinct from the receptor that mediates endocytotic uptake of acetylated low-density lipoprotein, but they share a common property of being inhibited by several polyanions, suggesting that polyanion-sensitivity might play an important role in the scavenger function of simusoidal liver cells. Studies on the ligand specificity of this receptor revealed that a covalent modification by formaldehyde of a limited number of lysine residues in albumin has led to the formation of a receptor-recognition domain(s). Furthermore, in addition to formaldehyde, the ligand activity was also generated with albumin modified by other aliphatic aldehydes, such as glycoaldehyde and glyceraldehyde. This phenomenon was extended to several proteins other than albumin. These data suggest therefore that the f-Alb receptor originally described as being specific for albumin modified by formaldehyde may play a general role as a scavenger receptor for aldehyde-modified proteins.