Prohormone convertases (PC1/3 and PC2) in rat and human pancreas and islet cell tumors: subcellular immunohistochemical analysis

Prohormone convertase 1/3 (PC1/3; also termed PC1 or PC3) and PC2 are enzymes that activate prohormones by cleaving the pairs of basic amino acids. This mechanism was initially inferred from the series of several endocrine and neuroendocrine precursor proteins, including proinsulin and proglucagon. To determine the cellular and subcellular distribution of PC1/3 and PC2 in the rat and human pancreas, immunohistochemistry was performed using polyclonal antisera against mouse PC1/3 (ST-28) and mouse PC2 (ST-29). These studies showed light and electron microscopic co-localization of insulin, PC1/3 and PC2, and the coexistence of glucagon and PC2 in the pancreatic islets. This tendency of colocalization was also depicted in one case of human insulinoma and three cases of human glucagonomas, as well as in rat insulinomas. In two cases of human insulinomas, incomplete processing of proinsulin was suggested by the absence of PC2. At the subcellular level in the rat pancreatic islet, the colocalization of PC1/3 and insulin, and that of PC2 and glucagon, were observed in the same secretory granules by immunoelectron microscopy and image analysis. These studies suggest that PC1/3 and PC2 can function with the specificities in the processing of proinsulin and proglucagon into their active forms, respectively, in the normal and neoplastic pancreatic islets.

Expression of Pit-1 and estrogen receptor messenger RNA in prolactin-producing pituitary adenomas

The pituitary-specific transcriptional factor, Pit-1, is a member of the POU-domain family, which has a role in the development and differentiation of three pituitary cell types: somatotrophs, lactotrophs, and thyrotrophs. Recently, specific DNA-dependent interactions have been observed between Pit-1 and nuclear receptors, including: thyroid hormone receptor; retinoic acid receptor; glucocorticoid receptor; and estrogen receptor (ER). The cooperative interaction between Pit-1 and ER required for prolactin enhancer activity in rat pituitaries has been suggested. We analyzed the expression of Pit-1 messenger ribonucleic acid (mRNA) and ER mRNA in 15 human prolactin-producing adenomas using nonradioisotopic in situ hybridization. Their products were also studied by immunohistochemical analysis. Pit-1 mRNA was detected in 12 (80%) of 15 prolactin-producing adenomas. On the other hand, ER mRNA was detected in 14 (94%) of adenomas studied. mRNAs of Pit-1 and ER were detected more frequently than immunohistochemical expression of their products. By combined in situ hybridization and immunohistochemical examination, Pit-1 mRNA and ER mRNA were often colocalized with prolactin immunoreactivities. The colocalizations of Pit-1 mRNA and ER protein were observed in adenoma cells. The high incidence of the expression of ER mRNA in prolactin-producing adenomas may suggest cooperative interactions between Pit-1 and ER in functional differentiation and development of prolactin-producing adenomas.

Spontaneous antibody-secreting cells in the stomach of gastric cancer patients

The gastric mucosa has been regarded as an active site of humoral immunity since the discovery of Helicobacter pylori. The present study was conducted to determine the in vivo activity of gastric B cells in 53 gastric cancer patients. B-cell activity was measured by protein-A plaque assay, in which IgA-, IgM-, and IgG-plaque-forming cells (PFC) were counted. The number of PFC was associated with the stage of cancer, but the response of lymphocytes in a non-tumorous area (NML) and tumor-infiltrating lymphocytes (TIL) differed. PFC in both sites were decreased compared to n0 cancer in n1 lymph node metastasis-positive cancer, while only NML showed raised PFC in n2 + (P < 0.05, vs TIL). Cancer cells penetrating the submucosa caused the PFC of TIL (but not of NML) to decrease. Invasion of the intratumor capillary (V) or lymphatic (Ly) vessels also caused PFC to change, showing differences of Ig class; there was a decrease of PFC in V2 (IgG- and IgM-PFC) and in Ly2 (all Ig-PFC). IgA-PFC in Ly1 differed in TIL (decrease of PFC) and NML (increase). PFC also differed in TIL and NML in cancer cells, as follows: TIL < NML in tubular and poorly differentiated adenocarcinoma and TIL > NML in papillary and signet ring cell adenocarcinoma. Changes in lymph node (LNL) and blood lymphocytes were similar to those in gastric PFC whose IgA value was 10 times as much as that of LNL. The 5-year survival rate was significantly better in patients with lower rather than higher PFC such as 89% vs 68%. Gastric B cells thus appear to be active and to reflect gastric mucosal immunity.

Abundant expression of erythroid transcription factor P45 NF-E2 mRNA in human peripheral granurocytes

Transcription factor NF-E2 is crucial for regulation of erythroid-specific gene expression. p45 subunit of NF-E2 contains a basic-leucine zipper domain and dimerizes with the small Maf family protein to form functional NF-E2 complex. While p45 expression was shown to be restricted to erythroid cells, megakaryocytes and mast cells in hematopoietic lineage, we found in this study that p45 mRNA is abundantly transcribed in the granulocyte fraction of human peripheral blood cells. As neutrophils occupy approximately 92% of the cells in granulocyte fraction of human peripheral blood cells. As neutrophils occupy approximately 92% of the cells in this fraction, the cells expressing p45 is most likely to be neutrophils. p45 mRNA is also expressed in HL-60 promyelocytes, albeit the expression level is much lower than that of the granulocyte fraction. HL-60 cells were found to express mafK mRNA, indicating the presence of genuine NF-E2 complex in the cells. Although p45 mRNA is transcribed from two different promoters, aNF-E2 promoter and fNF-E2 promoter, in erythroid and megakaryocytic lineage cells, p45 mRNA is transcribed only from aNF-E2 promoter. The expression of p45 megakaryocytic lineage cells, p45 mRNA is transcribed only from aNF-E2 promoter. The expression of p45 mRNA in the neutrophils declined rapidly after transfer of the cells to in vitro culture and G-CSF could not sustain the expression from the down-regulation, suggesting the E2 may also participate in the regulation of neutrophil-specific gene expression.

In situ hybridization analysis of Pit-1 mRNA and hormonal production in human pituitary adenomas

The pituitary-specific transcriptional factor, Pit-1, is a member of the POU-domain family which has a role in the development and differentiation of three pituitary cell types: somatotrophs, lactotrophs, and thyrotrophs. Recent investigations have suggested the involvement of specific regulation of Pit-1 transcripts in human pituitary adenomas. In this study, we analyzed the expression of Pit-1 gene and Pit-1 product in various human pituitary adenomas using in situ hybridization (ISH) and immunohistochemistry (IHC). Northern hybridization analysis revealed 2.4- and 4.1-kb Pit-1 transcripts in normal pituitary, growth hormone (GH)-, prolactin (PRL)- and thyrotropin (TSH)-secreting adenomas. By ISH analysis, Pit-1 mRNA was detected in 42 (84%) of 50 adenomas. The highest incidence was observed in 15 GH-secreting adenomas and 8 TSH-secreting adenomas, in which Pit-1 mRNA was detected in all cases. Pit-1 mRNA expression was detected in 11 (85%) of 13 PRL-secreting adenomas. In 12 clinically non-functioning adenomas, Pit-1 mRNA was also present in 8 cases, and 5 of these were associated with immunohistochemical expression of Pit-1 product. By combined ISH and IHC, Pit-1 mRNA was often colocalized with GH, PRL or TSH beta immunoreactivities and sometimes colocalized with alpha-subunit of glycoprotein (alpha SU) immunoreactivity. The expression of Pit-1 mRNA in various cell types of human pituitary adenomas in addition to GH, TSH beta and PRL immunoreactivities suggests that Pit-1 may play a role in functional development of pituitary adenomas, including clinically non-functioning adenomas. However, some additional transcriptional factors or enhancers may be required.

[Isolated angiitis of the central nervous system presenting as subcortical hemorrhage--a case report of benign type]

A 47-year-old woman had an episode of severe headache for a few days. She suddenly experienced right leg weakness and sensory loss. A CT scan revealed subcortical hematoma at the left parietal lobe on admission. Cerebral angiography showed multiple vascular irregularities such as segmentally narrow or sausage-like dialatated areas. Her laboratory studies were entirely normal including antinuclear antibody and coagulation tests. The diagnosis of isolated angiitis of the CNS was made and she responded well to the low dose corticosteroid therapy. Repeated cerebral angiography two months after the onset demonstrated most of the areas of segmental irregularity had improved with a few unchanged areas. Some cerebral angiitis do exist that respond well to corticosteroid therapy, therefore, early diagnosis and treatment are suggested in cases of angiitis.

The role of proinflammatory and immunoregulatory cytokines in the pathogenesis of ulcerative colitis

We investigated the production of proinflammatory cytokines (IL-1 beta, IL-6, IL-8, and TNF-alpha) and immunoregulatory cytokines (IL-2, IFN-gamma, and IL-10) in the colonic mucosa of patients with active ulcerative colitis (UC), inactive UC, and non-inflammatory bowel disease (IBD) colitis by organ culture. The production of proinflammatory cytokines was significantly increased in all the studied groups compared with controls. In active UC, levels of these cytokines, except for IL-1 beta, were markedly increased compared with non-IBD colitis, and the levels were positively correlated with the degree of inflammation. Patients with non-refractory active UC receiving steroids showed levels of IL-1 beta and TNF-beta production similar to those in controls. IL-10 production was also significantly increased in all the studied groups, the value of being the highest in active UC. In contrast, IL-2- and IFN-gamma production was significantly decreased in both active and inactive UC compared with controls, and the values in active UC were inversely correlated with the degree of inflammation. In non-IBD colitis, decreased IL-2 production was observed, but IFN-gamma production did not differ from that in controls. In an experimental study, each of the proinflammatory cytokines was injected into the colonic mucosa of rats. All of these proinflammatory cytokines, except for IL-1 beta induced colonic mucosal damage that showed some histologic features similar to those of UC. These results suggest that the increased production of proinflammatory cytokines, particularly of IL-6 and IL-8, and the decreased production of IL-2- and IFN-gamma, probably downregulated by the enhanced production of IL-10, play an important role in the pathogenesis of UC.

Pregnancy outcome among long-term survivors with acute leukemia

By means of a mail questionnaire, we evaluated the influence of treatment for acute leukemia on offspring of long-term survivors and determined whether the outcome of pregnancy in patients (or spouses) induced relapse of acute leukemia. In 322 replies from the 445 institutions where a questionnaire was sent, there were 1136 adult long-term survivors. We analyzed the 43 adults who had become pregnant or become a father after postremission therapy. The mean age at the leukemia onset was 26.4 and 21.6 years for males and females. Forty-six normal children (26 boys and 20 girls) were born of long-term survivors including 7 pairs of siblings and a pair of twin sisters. There were no malformed babies. There were five abortions. The average duration until delivery was 79 months after diagnosis, and 49 months after the final postremission therapy. Four of 38 parents of live offspring died (3 relapse, 1 other disease), and the other 34 parents of live offspring were in complete remission at the point of this survey. The adverse effect of treatment on the offspring of long-term survivors could not be clarified in this survey. Additional lifetime follow-up of long-term survivors with acute leukemia and their offspring may be necessary.

Immunohistochemical characterization of "hyperplasia-adenoma sequence" in the pituitaries of transgenic mice expressing a human growth hormone-releasing factor gene

The morphology of hyperplastic pituitaries in seven human growth hormone-releasing factor (hGRF) transgenic mice were compared to those of two normal control mice. Under continuous stimulation by hGRF, both the total volume of the pituitary and the size of individual cells increased, and a nodular lesion, designated a "hypertrophic nodule", was identified. Immunohistochemically, the hyperplastic pituitaries consisted of various numbers of cells immunoreactive for rGH, rPRL, hACTH, rLH beta, hFSH beta, and r alpha SU, whereas the "hypertrophic nodule" was composed of rGH, rPRL, and rTSH beta positive cells, similar to the adenoma. The presence of the "hypertrophic nodule", which was intermediate in appearance between the controls and the adenomas, suggests a close relation between continuous hGRF stimulation and the development of a hyperplasia-adenoma sequence in the pituitary.

Collagenous colitis

Collagenous colitis is characterized clinically by chronic watery diarrhea and pathologically by colonic mucosal subepithelial collagen deposition. We report a 72-year-old woman who had collagenous colitis associated with chronic watery diarrhea. She received a non-steroidal anti-inflammatory agent (sulindac) because of rheumatoid arthritis. Histological examination of biopsy showed a thick subepithelial collagen layer with lymphocytes, plasma cells, and infiltration of a few eosinocytes in the lamina propria. These findings led to the diagnosis of collagenous colitis. After treatment with salazosulfapyridine, her bowel movement became normalized and mucosal subepithelial collagen deposition disappeared.

Clinical application of 18F-FUdR in glioma patients--PET study of nucleic acid metabolism

Positron emission tomography was used to investigate the metabolism of nucleic acids by 18F-fluoro-2'-deoxyuridine (18F-FUdR) in 22 patients with gliomas. Sixteen cases of high grade glioma clearly demonstrated a region of high activity with a differential absorption rate (DAR) of 0.64 +/- 0.34. Six cases of low grade glioma failed to reveal a positive image of the tumor and the DAR in tumor was 0.21 +/- 0.042 (p < 0.01). This PET-18F-FUdR study succeeded in differentiating high and low grade gliomas from the view point of nucleic acid metabolism.

[Exacerbation of seizures by carbamazepine in four children with symptomatic localization related epilepsy]

We treated one hundred and seventy-eight epileptic children with carbamazepine (CBZ) for eight years. Among them, four children with symptomatic localization-related epilepsy, aged 11 months to 12 years, developed exacerbation of seizures. Their epilepsies were associated with hypoxic ischemic encephalopathy, head injury and ectopic gray matter. Despite the serum levels of CBZ (7.0 approximately 9.5 micrograms/ml) being within the therapeutic range, all of them had more frequent and severe partial seizures than before taking CBZ and one developed new atonic seizures. Diffuse irregular spike-wave complexes appeared on EEG in two children. Following discontinuation of CBZ in addition to replacement with phenytoin, their seizures became well-controlled and EEG findings improved except for residual focal spikes. Although CBZ is a widely used and effective antiepileptic drug for partial seizures, it should be kept in mind that CBZ may exacerbate seizures in children with symptomatic localization-related epilepsy.

Clinical and immunohistochemical studies on TSH-secreting pituitary adenoma: its multihormonality and expression of Pit-1

Eight patients with thyrotropin (TSH)-secreting pituitary adenoma are described. Serum TSH levels were inappropriately elevated in spite of elevated thyroid hormones. The serum-free glycoprotein alpha-subunit level was elevated in all the patients. The alpha-subunit to TSH molar ratio, a "tumor marker" for TSH-secreting adenoma, ranged from 1.06 to 6.16. All patients had macroadenoma and underwent transsphenoidal surgery. Light-microscopic indirect immunoperoxidase method applied on formalin-fixed paraffin-embedded specimens revealed alpha-subunit and TSH beta immunoreactivity in all adenomas. The proportion of TSH beta-positive cells ranged from 20% to 75% of adenoma cells. Six adenomas (75%) were associated with growth hormone (GH) and/or prolactine (PRL) immunoreactivity. By the double staining method, TSH beta and the alpha-subunit were frequently colocalized in the same cells, but some cells were found to contain either alpha-subunit or TSH beta. We also analyzed the localization of a pituitary-specific transcriptional factor, Pit-1, which has been suggested to play a role in functional differentiation toward growth hormone, prolactine, and TSH. All cases were positive for Pit-1 product using antibody against human Pit-1 synthesized peptide. Pit-1 product was localized in the nuclei of many adenoma cells and was frequently identified in cells that were positive for both TSH beta and growth hormone or prolactine. From our investigations, the role of Pit-1 in multidirectional differentiation during the development of TSH-secreting adenoma was suggested.

Management of acute leukemia during pregnancy: from the results of a nationwide questionnaire survey and literature survey

In March, 1993, a questionnaire was sent to 362 gynecological and obstetric offices of national, prefectural and municipal hospitals and private university hospitals with 250 beds or more. Answers were collected from 260 institutions. Thus, this study analyzed 39 patients with acute leukemia during pregnancy collected by the questionnaires survey and 64 cases reported in the Japanese literatures during 1975-1993 (total 103 patients). The weeks of pregnancy were defined as the 1st (< 15th week), 2nd (16th-27th week), and 3rd (> 28th week) trimesters. The time of diagnosis of leukemia during pregnancy changed from 25% in the 2nd trimester and 62% in the 3rd trimester during 1975-1984 to 39% and 48% after 1985, respectively. After 1985, the remission rate was 72% in the questionnaire group and 75% in the group from literatures. There was no statistical difference. The 50% survival period was 12 months in the group during 1975-1984, but 25 months in the group after 1985. The survival was significantly longer in the patients whose induction therapy was started before delivery than in those treated after delivery. The results suggest that the treatment for acute leukemia during pregnancy should be initiated as soon as possible after the diagnosis of leukemia, with carefully selected regimens. It is important that the time of delivery should be selected considering the maternal and fetal conditions after consultation with an obstetrician.

Bio-histochemical aspects of integrins (alpha 2 beta 1, alpha 6 beta 1) in invasive mammary carcinomas: an immunohistochemical study

Immunohistochemical expression of integrins was examined in 39 human invasive mammary carcinomas, of which 34.2% and 43.6% expressed integrins alpha 2 beta 1 and alpha 6 beta 1, respectively. Immuno-electron microscopy clearly demonstrated that the integrins were in the cell membrane of the carcinoma cells. Similar expression of integrin alpha 2 beta 1 or alpha 6 beta 1 in both the intraductal component and invasive portion of the same tumor was seen in 76.9% and 85.7% of cases, respectively. This suggested that invasive carcinoma cells retained their integrin expression after invasion through the basement membrane. Reciprocal expression of integrins alpha 2 beta 1 and alpha 6 beta 1 was seen in 20 cases. Expression of alpha 2 beta 1 was seen significantly less frequently in scirrhous carcinoma than in the more differentiated papillotubular or solid tubular carcinoma (Chi-squared test, P < 0.05). Intraductal components of carcinoma were present more frequently in cases expressing integrin alpha 2 beta 1 than in those that were negative. This suggests the potential usefulness of integrins as clinical parameters in the surgical treatment of mammary carcinoma, since recent trials of conservative treatment for mammary carcinoma have focused on the intraductal spread of the tumor cells.

Behavioral evidence for a modulating role of sigma ligands in memory processes. I. Attenuation of dizocilpine (MK-801)-induced amnesia

The potentiating effect of low doses of sigma ligands on the N-methyl-D-aspartate (NMDA)-induced excitation of pyramidal CA3 dorsal hippocampal neurons has recently been reported. In the present study, we investigated behavioral effects relevant to these findings in the experimental amnesia induced by the non-competitive NMDA antagonist, dizocilpine (MK-801), in mice. At doses below 1 mg/kg s.c., the sigma ligands, 1,3-di-(2-tolyl)guanidine (DTG), (+)-SKF 10,047, and (+)-pentazocine, but not their (-)-isomers, significantly decreased MK-801 (100 microgram/kg s.c.)-induced impairment of spontaneous alternation performances in 8-min sessions of a Y-maze exploration, an index of spatial working memory, without affecting the concomitant hyperlocomotion. The effect of DTG (100 micrograms/kg s.c.) was completely antagonized by the simultaneous administration of BMY 14802 (10 mg/kg i.p.) and NE-100 (1 mg/kg i.p.), two putative sigma antagonists, which had no effect by themselves. In long-term memory tests (step-down and step-through types of passive avoidance, elevated plus-maze), DTG exhibited a significant attenuation of MK-801-induced amnesia, at doses of 10 and 100 micrograms/kg s.c. In all tests of short- and long-term memory, the effects exhibited by the sigma ligands tested had a bell-shaped curve; no effect was seen at 1 mg/kg. DTG did not affect the impairment of alternation induced by CPP (5 mg/kg i.p.): the modulation may selectively target the blockade of NMDA receptor-associated ion channels. Moreover, DTG (1-1000 micrograms/kg) did not affect the impairment induced by scopolamine (1 mg/kg i.p.) or diazepam (4 mg/kg i.p.), but significantly prevented the impairment induced by mecamylamine (10 mg/kg i.p.). These results suggest that the potentiating effect of sigma ligands on NMDA receptor-mediated glutamatergic neurotransmission, already demonstrated electrophysiologically, may have some relevance to learning and memory processes in the hippocampus. A similar modulation may also affect cholinergic nicotinic systems.

Nephritogenic antibodies in MRL/lpr lupus mice: molecular characteristics in pathological and genetic aspects

MRL/lpr mice spontaneously develop a lethal glomerulonephritis (GN). We found that IgG3 production in this strain of mice has a critical role on the development of GN; 1) IgG3 levels were high in kidney-extracted IgG and in circulating IgG immune complexes (IC), 2) serum IgG3 was selectively reduced by cyclosporin A treatment, associated with amelioration of GN, and 3) the mRNA levels of IgG3 correlated well with the severity of GN among the MRL/lpr x (MRL/lpr x C3H/lpr) F1 backcross mice with the rearranged genetic profile. Based on these results, we have successfully established five hybridoma clones which produce nephritogenic IgG3 antibodies from an unmanipulated MRL/lpr mouse. When they were injected to normal mice, four of the five clones generated cell-proliferative GN associated with the marked cellular infiltrates, while the remaining clone induced wire loop-like lesions. This result suggests that particular antibodies generated in MRL/lpr mice have a different pathogenic potency. The V-region sequence study of these nephritogenic antibodies revealed that the two types of the glomerular lesions were mediated by a different B cell precursor. In conclusion, GN in MRL/lpr lupus mice is thought to be generated by the expansion of clonally different B cells producing nephritogenic antibodies with a different pathogenic potency.

Enhanced expression of transforming growth factor-beta s and transforming growth factor-beta type II receptor in the synovial tissues of patients with rheumatoid arthritis

BACKGROUND

A growing body of evidences suggests that transforming growth factor-beta (TGF-beta) is produced in the synovial fluid of patients with rheumatoid arthritis (RA), and that TGF-beta is an important regulator in the course of the disease. Careful studies on the endogenous synthesis of TGF-beta as well as its receptors are therefore necessary to clarify the possible role of TGF-beta in RA.

EXPERIMENTAL DESIGN

We examined the expressions of latent TGF-beta 1, -beta 2, and -beta 3, the latent TGF-beta 1-binding protein (LTBP) as well as TGF-beta type II receptor (TGF-beta RII) in the synovial biopsy tissues of 21 patients with RA by immunohistochemistry. Five specimens from these cases representing both active and chronic inactive stages were also examined for the corresponding mRNA by in situ hybridization. Northern blot analysis was performed on 3 synovial membranes taken from the RA patients together with a control synovium.

RESULTS

Abundant LTBP, TGF-beta 1, and TGF-beta RII-positive cells as well as less intensively stained TGF-beta 2 and TGF-beta 3-positive cells were found in the synovial layer. These cells were positive for the histocompatibility antigen, HLA-DR. In lymphocyte aggregates, scattered cells positively labeled for LTBP and TGF-beta 1 were found. They stained in a reticular pattern that was similar to that demonstrated by an antibody against human dendritic cells, and also expressed HLA-DR. In situ hybridization revealed markedly increased signals for LTBP and TGF-beta RII mRNA in tissues with an active inflammatory process, when compared with tissues with less active inflammation. However, no clear differences in the levels of expression for any of the TGF-beta isoforms were found. Specimens with pronounced fibrosis, fibroblasts, and surrounding collagen fibers expressed positive immunoreactivities for all TGF-beta isoforms and LTBP. Northern blot analysis on 4 synovial tissues demonstrated positive signals for LTBP and TGF-beta 1 mRNA in all three RA patients in contrast to a normal control, which did not show any signals. An increased expression of TGF-beta RII mRNA was detected in the tissue from one of the patients.

CONCLUSIONS

An abundant expression of TGF-beta 1 and LTBP, as well as TGF-beta RII was seen in most actively proliferating synovial intimal cells, and the level of the expression varied during the course of the disease. We conclude that TGF-beta is involved tightly in the regulation of the inflammatory process, and it is thus possible that the endogenous TGF-beta functions as a self-regulator that induces the remission periods.

Low dose of 1,3-di(2-tolyl)guanidine (DTG) attenuates MK-801-induced spatial working memory impairment in mice

MK-801 (30-100 micrograms/kg, SC) impaired spontaneous alternation behavior of mice, a behavior related to the spatial working memory. 1,3-Di-(2-tolyl)guanidine (DTG), (+)-pentazocine and (+)-SKF 10,047 (100 micrograms/kg, SC), putative sigma agonists, administered 10 min before MK-801, partially but significantly reversed the impairment, without affecting the concomitant hyperlocomotion. The antagonizing effects by DTG were prevented by BMY-14802 (5 mg/kg, IP), a purported sigma antagonist. These findings suggest that, at low doses, sigma ligands may modulate the N-methyl-D-aspartate dependent memory processes.

Dynorphin A-(1-13) potently improves the impairment of spontaneous alternation performance induced by the mu-selective opioid receptor agonist DAMGO in mice

The effects of i.c.v. injection of the mu-selective opioid receptor agonist DAMGO and the effects of its combination with the endogenous kappa-opioid receptor agonist dynorphin A-(1-13) on memory processes were examined in mice, using spontaneous alternation performance associated with working memory in a Y-maze. DAMGO (10 and/or 30 ng) impaired spontaneous alternation performance and increased total arm entries, which are considered to reflect locomotor activity. beta-Funaltrexamine (5 micrograms, i.c.v.), a mu-selective opioid receptor antagonist, almost completely antagonized the impairment of alternation performance induced by DAMGO (10 ng). Physostigmine (0.1 mg/kg, i.p.), a cholinesterase inhibitor, improved the DAMGO (10 ng)-induced impairment of alternation performance. Dynorphin A-(1-13) (1, 3 and 10 micrograms, i.c.v.) alone was without significant effects on alternation performance. On the other hand, dynorphin A-(1-13) (3 and 10 micrograms) significantly improved the impairment of spontaneous alternation performance induced by DAMGO (10 ng). The effects of dynorphin A-(1-13) (3 micrograms) on the DAMGO-induced impairment of spontaneous alternation were almost completely reversed by pretreatment with nor-binaltorphimine (4 micrograms, i.c.v.), a kappa-selective opioid receptor antagonist. The present results demonstrate that DAMGO impairs alternation performance by activating mu-opioid receptors, whereas dynorphin A-(1-13) attenuates the DAMGO-induced impairment of alternation performance through the mediation of kappa-opioid receptors. These findings suggest that mu- and kappa-opioid systems are fully involved in memory function and have opposite effects on spontaneous alternation performance as it is reflected by working memory in mice.

Induction of different types of glomerulonephritis by monoclonal antibodies derived from an MRL/lpr lupus mouse

MRL/Mp-lpr/lpr(MRL/lpr) lupus mice develop glomerulonephritis in which the histopathological manifestations of the disease are characterized by diffuse cell-proliferative, crescentic, and/or wire loop-like lesions, resembling those of human lupus nephritis. Although these lesions are thought to be mediated by antibodies, little data is available to explain these regular variations in glomerular lesions induced by antibodies at the monoclonal level. We studied glomerular lesions of normal or severe combined immunodeficient mice injected with nephritogenic immunoglobulin G3-producing hybridoma clones (2B11.3 and 7B6.8), which we previously established from an unmanipulated MRL/lpr mouse. Both clones caused increased serum levels of immunoglobulin G3 with identical patterns over time and both induced glomerular deposits of immunoglobulin G3 and C3. However, 2B11.3 and 7B6.8 induced glomerular lesions that differed in their histopathological manifestations. The 2B11.3 clone generated cell-proliferative lesions associated with marked Mac-2-positive macrophage infiltrates, but the 7B6.8 clone induced lesions characterized by subendothelial hyaline deposits resembling wire loops. The latter was not associated with significant inflammatory cell infiltrates at any point throughout the progression of the lesion. Thus, our findings suggest that the histopathological variation in glomerulonephritis seen in MRL/lpr mice results from clonally expanded B cell clones that produce nephritogenic antibodies with different pathogenic potencies.

Dopaminergic involvement in the improving effects of dynorphin A-(1-13) on scopolamine-induced impairment of alternation performance

The present study was designed to clarify whether dopamine systems are involved in the effect of dynorphin A-(1-13), an endogenous kappa-opioid receptor agonist, on the scopolamine-induced impairment of spontaneous alternation performance related to working memory in mice. Sulpiride (10 and/or 30 mg/kg), a dopamine D2-selective antagonist, markedly improved the impairment of alternation performance and significantly reduced the increase in total arm entries (i.e. locomotor activity) induced by scopolamine (1 mg/kg). In contrast, SCH 23390 (0.01, 0.03 and 0.1 mg/kg), a dopamine D1-selective antagonist, did not influence the impairment of alternation performance, whereas it dose dependently reduced total arm entries in scopolamine-treated mice RU 24213 (1 mg/kg), a dopamine D2-selective agonist, almost completely reversed the improving effect of dynorphin A-(1-13) (3 micrograms) on the scopolamine-induced impairment of alternation performance and reduced total arm entries, although it was without effects on behavioral responses in normal mice. However, SKF 38393 (3 and 10 mg/kg), a dopamine D1-selective agonist, failed to change alternation performance or total arm entries in normal or scopolamine-treated mice. These findings suggest that the impairment of spontaneous alternation performance induced by scopolamine is improved by the blockade of dopamine D2 receptors. Furthermore, the improving effect of dynorphin A-(1-13) on the scopolamine-induced impairment of spontaneous alternation performance may be based upon the inhibition of dopaminergic activity through the mediation of kappa-opioid receptors.