Lipid mediators and protein kinase C for intracellular signalling

1. The stimulation of a cell surface receptor initiates a degradation cascade of various membrane lipid constituents. 2. Many of their metabolites have potentials to induce, intensify and prolong the activation of protein kinase C that is needed for sustained cellular responses.

Immunohistochemical study of apolipoprotein E in human cerebrovascular white matter lesions

In the brains of ine cases with cerebrovascular disease, one with mixed dementia, one with amyloid angiopathy and two non-neurological controls, we found three cases with focal accumulation of apolipoprotein E (apo-E) in dystrophic axons and accompanying macrophages. Since amyloid precursor protein (APP) and chromogranin A (CgA) accumulate after axonal damages, and are sensitive markers of the white matter lesions, the regional distribution of apo-E was compared to that of APP and CgA. apo-E-immunoreactive axons were present in the periphery of an infarction with neighboring macrophages, but not in mild white matter lesions that contained APP- or CgA-immunoreactive fiber bundles. The results suggest a role of apo-E in recycling cholesterol and other membrane components via macrophages into remodeling neurites in the brain, but this phenomenon is restricted to the periphery of infarction and may be less prominent than in the peripheral nervous system.

Low intensity areas observed on T2-weighted magnetic resonance imaging of the cerebral cortex in various neurological diseases

The cerebral cortex of patients with Alzheimer's disease (AD) or amyotrophic lateral sclerosis (ALS) may show low signal intensity on T2-weighted magnetic resonance images (MRI). Since these low intensity areas (LIA) are also often observed in aged patients with other diseases, we suspected that they might be a non-specific finding. We conducted a retrospective study of LIA in 139 patients with various diseases of the central and peripheral nervous systems, and evaluated their relationship to age and other MRI findings. Brain atrophy, ventricular dilatation, white matter lesions, and LIA were visually evaluated on axial images of the spin echo sequences obtained with a 1.5 tesla (T) system. We found that LIA appeared after age 50 and became more common with advancing age. Their presence correlated with brain atrophy and white matter lesions. They were most frequent in the motor cortex, followed by the occipital and sensory cortices. Their incidence in the motor cortex was significantly higher in patients with central nervous system diseases than in those with peripheral neuropathy. We conclude that LIA are common in old patients with various neurological diseases and suggest that the deposition of iron in the cerebral cortices causes their development.

The melanotropic peptide, [Nle4,D-Phe7] alpha-MSH, stimulates human melanoma tyrosinase activity and inhibits cell proliferation

Seventeen human melanoma cell (HMC) lines, both melanotic and amelanotic, were incubated in the continuous presence of a potent melanotropic peptide hormone analog, [Nle4,D-Phe7] alpha-MSH, for 72 hr with daily changes of medium. Only one cell line (HD, melanotic) consistently responded to the hormone analog by increased tyrosinase activity. Three (one melanotic, two amelanotic) of the HMC lines also failed to respond to the peptide by either increased or decreased enzyme activity when incubated continuously in the presence of the peptide for longer periods of time (6,15,27,43 days). The HD cell line, however, again responded with increasingly enhanced basal enzyme activity the longer the cells were incubated in the presence of the melanotropin. One amelanotic cell line (C8161) responded with enhanced enzyme activity when grown to confluency in the continuous presence of the peptide. Basal tyrosinase activity of the C8161 cell line may have increased as cell density in the flasks increased. These results suggest that under conditions of increased cell number, phenotypic expression of tyrosinase activity in so called "amelanotic" (tyrosinase-negative) cells is increased and can be enhanced further by stimulation with a melanotropic peptide. Under conditions of increased cell number, the presence of [Nle4,D-Phe7] alpha-MSH caused morphological differentiation (shape change); the cells became enlarged and very dendritic. The number of cells in monolayer (surface of the flask) and in the medium were drastically reduced in both melanotic and "amelanotic" cell lines incubated with [Nle4,D-Phe7] alpha-MSH. The data support other published reports that melanotropic peptides inhibit human melanoma cell growth (proliferation) in vitro, most likely through a cytostatic mechanism. [Nle4,D-Phe7] alpha-MSH also exhibited a prolonged (residual) inhibitory action on HD cell proliferation. In other words, inhibition of cell growth (proliferation) of the HMCs was evident even several days after removal of the melanotropic peptide from the incubation medium.

Monoamine oxidase-B-positive granular structures in the hippocampus of aged senescence-accelerated mouse (SAMP8)

We examined the histochemical localization of monoamine oxidase in the hippocampus of young and old senescence-accelerated mouse (SAM). We found a monoamine oxidase-B-positive granular structure (MGS) in the hippocampus of old SAMP8, an accelerated senescence-prone line of SAM. The MGS was a round-shaped granular structure of 0.5 to 5 microns diameter and usually formed a cluster, the largest diameter of which ranged from 50 to 150 microns. No MGS were found in the hippocampus of young SAMP8 or of young SAMR1, an accelerated senescence resistant line of SAM, and only few, if any, were seen in old SAMR1. A monoamine oxidase-positive astrocyte was usually observed in the central area of each cluster of MGS. Furthermore, the MGS was in close anatomical relationship with monoamine oxidase-positive astrocytic processes. The enzyme inhibition experiments showed that monoamine oxidase activities localized in the MGS and astrocytes were both predominantly of type B. These findings suggest MGS occurs at least partly in monoamine oxidase-B-positive astrocytes. Furthermore, the MGS was similar to a periodic acid-Schiff-positive granular structure, a polyglucosan body previously documented in the brains of old SAMP8 and some other aged mice strains including C57BL/6 and nude mice, in terms of their size, morphological appearances and topographical distribution in the hippocampus. Thus, the present results suggest that monoamine oxidase type B is a proteinaceous component of the periodic acid-Schiff-positive granular structure in aged mice brains, and might provide some clues for clarifying the mechanisms of age-related occurrence of periodic acid-Schiff-positive granular structures in mice brains.

DNA single-strand breaks in postischemic gerbil brain detected by in situ nick translation procedure

Using an in situ nick translation procedure, DNA single-strand breaks (SSB) in postischemic gerbil hippocampus were investigated after 15-min forebrain ischemia followed by 0-4h of recirculation. In the control group, increased SSB were noticed in the ependymal cell layer and the dentate gyrus. After 15-min ischemia without recirculation, no remarkable changes in SSB were observed. However, after 1 h of recirculation, a marked increase in SSB was recognized throughout the hippocampus, especially in the cells in CA1 subfield and the dentate gyrus. After 4 h of recirculation, SSB decreased to a level near that of the control group. The results of the present study indicate that ischemic insults may injure intranuclear DNA during postischemic recirculation periods. Although many factors may be involved, activated endonuclease due to an intracellular Ca2+ rise, free radicals, and postischemic hyperthermia appear to be involved in this phenomenon.

Requirement of Saccharomyces cerevisiae Ras for completion of mitosis

In the yeast Saccharomyces cerevisiae, Ras regulates adenylate cyclase, which is essential for progression through the G1 phase of the cell cycle. However, even when the adenosine 3',5'-monophosphate (cAMP) pathway was bypassed, the double disruption of RAS1 and RAS2 resulted in defects in growth at both low and high temperatures. Furthermore, the simultaneous disruption of RAS1, RAS2, and the RAS-related gene RSR1 was lethal at any temperature. The triple-disrupted cells were arrested late in the mitotic (M) phase, which was accompanied by an accumulation of cells with divided chromosomes and sustained histone H1 kinase activity. The lethality of the triple disruption was suppressed by the multicopies of CDC5, CDC15, DBF2, SPO12, and TEM1, all of which function in the completion of the M phase. Mammalian ras also suppressed the lethality, which suggests that a similar signaling pathway exists in higher eukaryotes. These results demonstrate that S. cerevisiae Ras functions in the completion of the M phase in a manner independent of the Ras-cAMP pathway.

Effects of mixed solvents on three elementary steps in the reactions of horseradish peroxidase and lactoperoxidase

The effects of methanol, acetone, and ethylene glycol (up to 50% v/v) on elementary steps in the reactions of horseradish peroxidase (HRP) and lactoperoxidase (LPO) were studied by means of the stopped-flow method and the difference spectrum. The rate constant (k3,app) of the oxidation reaction of p-cresol with HRP compound II was remarkably reduced in the presence of organic solvents (to 2.3%, 1.8% and 9.4% of the original value in the presence of 50% (v/v) of methanol, acetone and ethylene glycol, respectively), then to a lesser degree were decreased the rate of the oxidation reaction with LPO compound II, and the rate of the oxidation reaction with HRP compound I. These reductions in the reaction rates were not due to competitive inhibition of the solvents, but considered to be related to the degree of exposure of the electron transfer route to the medium. While the rate constant of compound I formation (k1,app) was moderately affected by organic solvents in the case of HRP, the reaction rate with LPO was scarcely affected by organic solvents, being in harmony with the compact heme crevice which probably hampers penetration of solvent molecules. The rate constant (k2,i,app) of the oxidation reaction of an iodide ion by HRP compound I was also hardly affected by the solvents. On the basis of these facts, the mechanism of electron transfer from donors to compound I and compound II is discussed.

Management of disseminated intra-abdominal lymphangiomatosis with protein-losing enteropathy and intestinal bleeding

We encountered an unusually severe case of intra-abdominal lymphangiomatosis associated with protein-losing enteropathy and intestinal bleeding. A low-fat diet effectively raised the patient's serum levels of hemoglobin and the total serum protein, perhaps by inducing a reduction in intestinal lymph flow and pressure.

N-myc protein expression in human breast carcinoma: prognostic implications

The overexpression of N-myc gene and its protein products has been thought to be limited to cases of neuroblastoma, retinoblastoma and small cell lung carcinoma, but there is increasing evidence of its wider distribution in human tumors. This study showed that the protein of N-myc gene is associated in normal, benign and malignant human breast tissues. We found that N-myc oncoprotein is overexpressed in most breast carcinomas and that N-myc overexpression is significantly correlated with clinical stage, and histological grading of the tumors, and, more importantly with the clinical outcome of the patients. Analysis of DNA, mRNA and protein levels suggested that the high N-myc expression in breast cancer occurs without concomitant gene amplification. The finding of a direct inverse correlation between N-myc overexpression and the prognosis of patients with breast carcinoma suggests that N-myc expression may be useful as a prognostic factor in human breast cancer.

Clinicopathologic study of primary gastric lymphoma of B cell phenotype with special reference to low-grade B cell lymphoma of mucosa-associated lymphoid tissue among the Japanese

Resection specimens from 83 patients with primary gastric lymphoma (PGL) of B cell phenotype at stage IE and at stage IIE according to the Ann Arbor classification were investigated. Histologically, these lymphomas could be divided into four types: Type I lesions (n = 24) were entirely made up of MALT lymphoma; Type II lesions (n = 13) were predominantly MALT lymphoma containing one to a few foci of high-grade B cell lymphoma; Type III lesions (n = 22) consisted largely of high-grade lymphoma with small areas of low-grade MALT lymphoma; and Type IV lesions (n = 24) were pure high-grade B cell lymphoma, mostly of the large cell type. All patients had undergone primary gastric resection, and 14 received additional chemotherapy (n = 12), or both chemotherapy and radiotherapy (n = 2). The survival probability was significantly higher for Types I and II lymphomas than for Types III and IV tumors (P < 0.05 by the generalized Wilcoxon test). According to The General Rules for the Gastric Cancer Study by the Japanese Research Society for Gastric Cancer, the stage of disease showed a clear distinction between each of them (P < 0.01 by the generalized Wilcoxon test). This staging method seemed to serve well as a prognostic indicator. The histological typing of the PGL of the present series also seemed to correlate with the gross appearance, pathologic stage and prognosis. Furthermore, the expression of cyclin D1, bcl-2 and p53 protein, and PCNA was immunohistochemically investigated in 42 cases of the present series. Most of the low-grade PGL (Types I and II) had less than 60% PCNA-positive cells, whereas the high-grade PGL (Types III and IV) had more than 60% positive cells. In a study for cyclin D1 protein, no cases showed the nuclear staining pattern characteristic for mantle cell lymphoma, and the cytoplasmic staining frequently observed in the node-based large B cell lymphoma was seldom identified in the PGL. This discrepancy might suggest a lineage difference among the morphologically similar, but site-different, lymphomas. On the other hand, bcl-2 protein overexpression was almost equal in frequency between the gastric and node-based high-grade B cell lymphomas. This is in contrast to the reports from Western countries, in which the majority of high-grade gastric tumors were bcl-2 negative.

Effects of certain antiallergic drugs on experimental conjunctivitis in guinea pigs

Effects of certain antiallergic drugs on experimental conjunctivitis were studied with guinea pigs. Chlorpheniramine, ketotifen and levocabastine were effective in inhibiting histamine- and antigen-induced conjunctivitis in guinea pigs. By contrast, amlexanox was only effective in inhibiting antigen-induced conjunctivitis. Topical application of antigen released 46.5 +/- 3.8% of histamine from the conjunctiva in sensitized guinea pigs. Both levocabastine and amlexanox were effective in inhibiting conjunctival histamine release induced by antigen application. Lacrimal histamine contents were also increased after challenge. The increase in the histamine content of tears was inhibited by pretreatment with levocabastine and amlexanox, but no significant effect was observed with chlorpheniramine and ketotifen. From these findings, it is concluded that certain antiallergic drugs, but not amlexanox, exhibited potent inhibition on experimental conjunctivitis in guinea pigs. In addition, it has been established that measurement of histamine in the conjunctiva and tears as well as observation of conjunctivitis syndromes are useful for evaluating the effectiveness of antiallergic drugs on various kinds of allergic conjunctivitis in clinical situations.

Suppurative lesions without prominent epithelioid cell response in abscess-forming granulomatous lymphadenitis

To clarify the clinicopathological significance of the suppurative lesions without an epithelioid granulomatous response (SLs without Ep) in lymph nodes and their relationship to abscess-forming granulomatous lymphadenitis (AGL) and cat scratch disease (CSD), 10 cases were assessed clinicopathologically and immunohistologically. SLs without Ep were located in the subcapsular sinus, paracortical area and medullary cords, but not in the germinal centers. The microabscesses were surrounded by collections of monocytoid B-lymphocytes (MBLs), histiocytes without epithelioid features, neutrophils, small lymphocytes and small numbers of plasma cells. The majority of the MBLs seen in the SLs without Ep were of the large cell type. The histological triad of toxoplasmic lymphadenitis, i.e., reactive follicular hyperplasia, small clusters of epithelioid cells and aggregates of MBLs, were also seen in all cases. Some of the clinical and pathological findings in our 10 cases were characteristic of CSD, i.e., (1) cat exposure before the lymphadenopathy was in four of the 10 cases, (2) occurrence in autumn and winter months in all cases, (3) typical suppurative granulomas surrounded by palisaded epithelioid cells were in four of the 10 cases, and (4) Warthin-Starry silver stain-positive bacteria were detected in seven of the 10 cases. The results of our study suggest that SLs without Ep are an early stage of CSD.

Intravascular ultrasound appearance of normal and mildly diseased coronary arteries: correlation with histologic specimens

Intravascular ultrasound imaging was performed in vitro on six histologically normal and 104 minimally diseased arteries in patients aged 13 to 83 years. This study tested the hypothesis that normal coronary arteries produce a three-layer image that corresponds to the histologic layers of intima, media, and adventitia. The results showed a very good correlation between area of the echolucent ultrasound layer with the media and the inner echogenic layer with intimal area. In addition, a three-layer appearance was consistently seen when the internal elastic membrane was present with or without intimal hyperplasia. If the internal elastic membrane was absent, a three-layer appearance was still seen if the collagen content of the media was low. However, a two-layer appearance was observed when there was absence of the internal elastic membrane as well as a high collagen content of the media.

A clinicopathologic study of 233 cases with special reference to evaluation with the MIB-1 index

BACKGROUND

Few articles have analyzed the prognostic data from a large series of primary gastric lymphoma classified according to the concept of mucosa-associated lymphoid tissue (MALT).

METHODS

The resected specimens from 233 patients with primary gastric lymphoma were investigated retrospectively, including immunostaining with MIB-1 (Ki-67).

RESULTS

Histologically, 70 (30%) of the cases were low grade B-cell lymphoma of MALT, 27 (12%) low grade B-cell lymphoma of MALT with a focal high grade component, 100 (43%) high grade B-cell lymphoma of MALT, 15 (6%) other B-cell lymphomas, 14 (6%) T-cell lymphomas, and 7 (3%) undetermined. Macroscopically, 96 (41%) were superficial-spreading type, 100 (43%) mass-forming, 14 (6%) diffuse-infiltrating, and 23 (10%) unclassified. The MIB-1 index correlated with phenotype, histologic grade, stage, depth of invasion, and macroscopic type. A significantly better survival was noted for young patients, and those with tumors of a B-cell phenotype, histologic low grade, macroscopic superficial-spreading type, low stage, low depth of invasion, and low MIB-1 index. No significantly different survival rates were found between the patients who underwent gastric resection alone and those who also received additional chemotherapy. By Cox multivariate analysis, independent prognosticators included B-cell phenotype, low stage, and macroscopic superficial-spreading type.

CONCLUSIONS

In addition to stage, phenotype and macroscopic type are also important prognostic indicators of primary gastric lymphoma. Immunostaining with MIB-1 had limited independent value for predicting prognosis.

Senile plaques in an aged two-humped (Bactrian) camel (Camelus bactrianus)

Senile plaques with beta-protein as a major constituent are a conspicuous feature in the brains of aged humans, monkeys, dogs, and bears. We found cerebral senile plaques of the diffuse and primitive type, but not the classical type, in an aged female camel of more than 20 years old. The senile plaques and a few cortical capillaries were immunoreactive with anti-beta-protein serum. Congophilic amyloid deposition was detected in a small number of the capillaries, but not in the senile plaques. We believe this to be the first detailed report of senile plaques in a herbivore, and these findings suggest the possibility of senile plaque formation in a wide variety of mammalian species.

Cloning and sequencing of a cDNA for poplar endo-1,4-beta-glucanase

A cDNA for poplar endo-1,4-beta-glucanase was cloned by use of a synthetic oligonucleotide as probe. The probe was designed on the basis of the N-terminal amino acid sequence of the beta-glucanase from suspension-cultured poplar cells (Populus alba L.), and by complete nucleotide sequence of the cDNA was determined. The 1,614-bp cDNA contained an open reading frame of 1,482 base pairs, encoding 494 amino acids. Removal of a putative signal sequence from the deduced amino acid sequence of the polypeptide yielded a mature protein of 467 amino acids. Comparison of deduced amino acid sequences revealed that the poplar endo-1,4-beta-glucanase was 80% and 70% identity to avocado fruit and bean abscission endo-1,4-beta-glucanases, respectively. Hydropathy plot analysis of the deduced amino acid sequence suggests that poplar endo-1,4-beta-glucanase belongs to family E in terms of the cellulase catalytic domain, and avocado fruit and abscission bean endo-1,4-beta-glucanases also belong to this family. 2,4-D markedly increased the level of the endo-1,4-beta-glucanase mRNA in cultured cells, while GA3, benzyladenine and abscisic acid each repressed transcription of this mRNA. The transcript was also detected in the roots and stems of intact plants, although the level of mRNA was much lower in intact tissues than in cultured cells. Genomic Southern analysis indicated that a small family of gene for endo-1,4-beta-glucanase exists in poplar.

[Distal pulmonary vessels demonstration by magnetic resonance angiography and its usefulness in the diagnosis of peripheral nodules]

To evaluate the usefulness of MRA in the diagnosis of peripheral pulmonary nodules, 18 lung cancers and 12 old inflammatory nodules were studied employing multiplanar fast radiofrequency spoiled gradient echo sequence (SPGR) with phased array coils. For each case, 12 images in coronal and sagittal sections were obtained after administration of Gd-DTPA, and original images, maximum intensity projection (MIP) images and multiplanar reconstruction (MPR) images were used for the interpretation. In ten cases, MRA images were compared with resected specimens and we found that the minimum diameter of pulmonary vessels which could be demonstrated by our method was about 1.5mm. As the results of the interpretation of MRA images in 30 cases, venous involvement, which is one of the classical important findings indicative of malignancy, was clearly demonstrated in 15 of 18 (83%) lung cancers, whereas such involvement was detected in only 3 of 12 (25%) inflammatory nodules. Pulmonary MRA, especially MIP and MPR images could make it easy to identify involved vessels, and proved to be useful in differentiating pulmonary nodules.

[Aberrant expression of HLA-DR antigens on acinar and ductal epithelial cells of salivary glands in Sjögren's syndrome]

The major histocompatibility complex (MHC) class II antigens have been reported to play an important role in antigen presentation to T cells and influence the susceptibility to several autoimmune diseases, including Sjögren's syndrome (SS). In this paper, an aberrant expression of MHC class II antigens, especially HLA-DR antigens, on salivary glands of SS is described. HLA-DR antigens were immunohistochemically detected on acinar and ductal epithelial cells of SS patients but not those of healthy controls. This expression was observed in proximity to the periphery of dense lymphocytic infiltrates but sometimes not associated with lymphocytic infiltrates. These results are consistent with recent findings of HLA-DR antigen expression on target organs of various autoimmune diseases. Finally, we discussed a pathogenic role of HLA-DR antigens, aberrantly expressed on target organs of SS.

Plasma adrenomedullin in patients with primary aldosteronism

Adrenomedullin (AM) is a novel hypotensive peptide originally isolated from the pheochromocytoma tissue of humans. To examine the pathophysiological role of AM in primary aldosteronism (PA), the plasma concentration of AM in patients with PA was measured with a specific radioimmunoassay and compared to that in age- and sex-matched healthy normotensive subjects. In addition, the concentrations of AM as well as catecholamines in the plasma from both the adrenal vein and the inferior vena cava (IVC) were measured to determine whether or not the circulating AM in these PA patients is supplied from the adrenal medulla, which contains a much higher concentration of AM than any other human tissue does. The plasma concentration of AM in the PA patients (4.57 +/- 0.32 fmol/mL, n = 6) was significantly (P < .01) higher than that in the healthy subjects (3.06 +/- 0.20 fmol/mL, n = 12). A significant positive correlation (r = 0.62, P < .01) was observed between the mean blood pressure and the plasma AM level. The AM concentration in plasma from the adrenal vein was almost the same level as that from the IVC although the concentrations of both epinephrine and norepinephrine in the adrenal vein were much higher than those in the IVC. Therefore, it seems unlikely that the plasma AM in the PA patients is mainly supplied from the adrenal medulla. Judging from the potent hypotensive activity of AM, the present findings suggest that AM participates in defense mechanisms acting against the elevation of blood pressure in the patients with PA.

[Cytokine mRNA expression in the labial glands of patients with Sjögren's syndrome]

It has been found that the pattern of cytokine mRNA expression was closely associated with the initiation and the progression of the disease process. The cytokine mRNA expression in the labial glands of patients with Sjögren's syndrome was examined by a PCR-based method. Th1 cytokines, such as IL-2 and IFN-gamma, were consistently detected in all patients examined, while Th2 cytokines, such as IL-4 and IL-5, were detected in some cases with strong B cell accumulation in the labial glands. These results suggest that Th1 cytokines are essential in the induction and/or maintenance of the disease, while Th2 cytokines are involved in the progression of the disease process. Other studies were also reviewed and a role of cytokines, produced by T cells and the target organ, was discussed.