Release of cholecystokinin from rat cerebral cortex in vivo: role of GABA and glutamate receptor systems

Using cortical cups in chloralose-urethanized rats, the in vivo release of cholecystokinin-like immunoreactivity (CCK-LI) from cerebral cortex was examined. Resting levels of cholecystokinin-like immunoreactivity ranged from 20 to 30 pg/20 min sample. The addition of potassium (40 mM) in excess, resulted in a highly significant elevation in the levels of CCK-LI in the cortical superfusate. Deletion of calcium and the substitution of cobalt (10 mM), resulted in a significant reduction in both resting release and the release otherwise evoked by the addition of potassium. Focal electrical stimulation of the cortex (20 Hz), resulted in a significant (1.9 +/- 0.2-fold, n = 8) increase in the levels of CCK-LI. The addition of glutamate (10(-6)-10(-4) M) of kainic acid (10(-8)-10(-6) M), also resulted in significant elevations in the levels of CCK-LI. The co-administration of a putative glutamate receptor antagonist, kynurenic acid (10(-4) M) resulted in a significant reduction in the levels of release otherwise evoked by the addition of glutamate, but not by electrical stimulation. The addition of GABA (10(-5)-10(-3) M) resulted in a dose-dependent decrease in the resting release of CCK-LI, and the release evoked by glutamate. Picrotoxin (10(-6)-10(-4) M), resulted in a highly significant increase in the levels of CCK-LI in the cortical effluent. These results are consistent with a tonic GABAergic inhibition of CCK-releasing neurons. The treatment of the animal with diazepam (30 mg/kg, i.p.) also resulted in a significant reduction in resting release and the release otherwise evoked by focal cortical stimulation.     

A case of autoimmune hepatitis needed to be differentiated from EBV hepatitis, in that the histology of liver biopsy specimen was useful for diagnosis]

A 10-year-old girl with autoimmune hepatitis (AIH) was reported. She was admitted to our hospital because of cholestasis and elevation of liver enzymes for 2 months. Laboratory examination revealed that EBV-DNA copy number in the PBMNC (peripheral mononuclear cells) was 1.2 x 10(3) copies/microg of DNA, hypergammaglobulinemia, and positive antinuclear antibody, positive anti-smooth muscle antibody. The histology of her liver biopsy specimen revealed interface hepatitis, dense mononuclear cell infiltrates, mild fibrosis, and negative for EBV in situ hybridization assay indicating AIH and not EBV-associated hepatitis. She was treated firstly with methylprednisolone pulses, then will prednisolone p.o.+azathioprine p.o.. Intravenous cyclophosphamide pulse therapy was introduced because of her abnormal immune pathology. All abnormal laboratory parameters improved to normal levels within 2 months, and EBV-DNA copy number in the PBMNC became negative after 4 months. The histology of liver biopsy specimen was useful for the diagnosis of AIH in such a difficult case needed to be differentiated from EBV hepatitis.     

99mTc(V)-DMSA and99mTc-MDP uptake and no67Ga-citrate uptake in a case of primary pulmonary leiomyosarcoma

Tumor scintigraphy with 67Ga-citrate, 99mTc(V)-DMSA and 99mTc-MDP were performed on a patient with rare primary pulmonary leiomyosarcoma. While 67Ga-citrate accumulation to the tumor was not recognized, 99mTc(V)-DMSA and 99mTc-MDP scintigraphy showed relatively intense localization of the tracers in the lesion, and were very useful in suggesting the characteristics of the tumor.     

The diagnosis and treatment of esophageal perforations resulting from nonmalignant causes

Esophageal perforations are extremely difficult to diagnose and treat. We report herein our results of a review of 26 patients with esophageal perforation which were spontaneous in 11, iatrogenic in 11, and caused by a foreign body in 4. Surgical treatment was performed in 7 of the patients with spontaneous rupture, but the remaining 19 patients were treated conservatively. The abnormality was found by plain radiography (X-ray) in 22 (85%) of the 26 patients, and by computed tomography (CT) in all 13 patients who underwent this procedure. The detection rates by esophagography and esophagoscopy were 100%, or all of 25 patients examined, and 60%, or 9 of 15 patients examined, respectively. Of 12 patients with underlying diseases, 4 (33%) died after the perforation, whereas only 1 (7%) of 14 patients without any underlying disease died. Postoperative empyema developed in all of 3 patients treated by intraoperative unfixed intrathoracic drainage (UID), but in none of the 4 treated by fixed intrathoracic drainage (FID). Conservative treatment achieved satisfactory results for spontaneous esophageal ruptures confined to the mediastinum, and for iatrogenic perforations and esophageal perforations caused by foreign bodies, provided there was no serious underlying disease such as advanced cirrhosis. Moreover, intraoperative FID proved useful in helping to prevent postoperative empyema.     

Phenotypic modulation in cisplatin-resistant cloned cells derived from transplantable rat malignant fibrous histiocytoma

The histogenesis of malignant fibrous hlstlocytoma (MFH) was studled using clsplatln (CDDP)-resistant MT-R8 and MT-R9 cells derlved from cloned undlfferentiated MT-8 and flbrohlstlocytic MT-9 cells, resoecthfely, which had been established from transplantable rat MFH. CDDP concentrations requlred for 50% suppression of prollferation of MT-R8 and MT-R9 cells were 5.4– and 3.3-fold greater than those of parental MT-8 and MT-9, respectively. MT-R8 and MT-Rg showed the higher positive rates to histimytic lysosomal/ antigenic (ED1 and ED2) markers. The number of a-smoath muscle actin (SMA)-positive cells significantly Increased in MT-RB; SMA-positlve cells were also obsenred in MT-R9, but no difference was seen between MT-9 and MT-R9. MT-R8 and MT-R9 expressed both histiwytic and myofibroblastic phenotypes. However, the histology of subcutaneous tumors induced in syngeneic rats by MT-R8 and MR-R9 did not always reflect their in vitro nature. MT-R8 developed undiffer-entlated sarcomas similar to parental MT-8 tumors. In contrast, MT-R9 induced tumors with polytypic histologies such as the storiform growth pattern, neoplastlc growth of granular cells and myofibroblasts, osteosarcoma-like areas, collagen-rich areas containing well-developed fibroblasts and areas involvlng many lipoblasts. These In vivo observatfons suggest the multidlrectional differentiation of MT-R9 cells. Phenotypic modulation of rat MFH cells seemed to be easily induced by CDDP. A possible histogenesis of MFH was discussed based on the data collected.     

Genesis of pulmonary foam cells in rats with diet-induced hyper beta-lipoproteinaemia

Hyper beta-lipoproteinaemia in rats was produced by feeding a standard diet to which was added excess cholesterol and cholic acid, with or without olive oil, for 4, 8, and 12 weeks. The beta-lipoprotein percentage in serum lipoprotein electrophoresis and lipid contents in very low density lipoprotein and low density lipoprotein fractions in these rats were significantly higher than in the control rats fed the standard diet only. The percentage of foamy monocytes (FMs) to the total number of blood monocytes (BMs) from mononuclear leucocyte fractions and percentage of pulmonary foam cells (PFCs) to the number of alveolar macrophages (AMs) from bronchopulmonary lavage fluids in the rats increased with the extension of the feeding period and were significantly higher than those in the controls. An increase in the percentage of PFCs was closely correlated with that of FMs in the rats. FMs and PFCs had cytoplasmic fine vacuoles proved to be neutral lipid and cholesterol. Histologically, PFCs made an appearance in the lungs of all the rats as early as 4 weeks after the start of feeding. The degree of the PFCs' development increased as the feeding period lengthened. When latex particles were injected intravenously into rats at feeding week 4, the percentage of latex-ingested AMs to the number of AMs in the rats was significantly higher than that of the controls at 4 and 8 days post-injection. The percentage of latex-ingested PFCs to the number of latex-ingested AMs increased with the lapse of a day after injection and was significantly higher than that of the controls at 2, 4, and 8 days post-injection. The present findings suggest that the foamy transformation of BMs and their migration into the pulmonary alveoli may be a potential mechanism of the PFCs' development in rats with hyper beta-lipoproteinaemia.     

Immunohistochemical detection of hepatocellular carcinoma in the setting of ongoing necrosis after radiofrequency ablation.

After radiofrequency ablation (RFA), hepatocellular carcinoma undergoes complete necrosis and an ongoing necrosis that is irreversible and characterized histologically by disrupted cell outlines, homogenous cytoplasmic eosinophilia, and preserved nuclear staining, with the cells appearing quite distinct from viable cancer cells. Antibody to detect single-stranded DNA (ssDNA) specifically labeled nuclei in the setting of ongoing necrosis, but not viable tumor cells, whereas human mitochondrial antibody labeled the cytoplasm of viable cells but not cells of ongoing necrosis. The results demonstrate that RFA causes denaturation of both DNA and proteins and that the immunohistochemistry of ssDNA and mitochondrial protein is useful in detection of ongoing necrosis after RFA and provides pathological information on the validity of this procedure.     

The absence of DNA polymerase kappa does not affect somatic hypermutation of the mouse immunoglobulin heavy chain gene

During the immune response to T cell-dependent antigen, somatic hypermutation (SHM) is introduced into immunoglobulin (Ig) genes. The variable region is the target for SHM and it is here that DNA lesions are introduced and mutations are generated. It has been suggested that error-prone DNA polymerase(s) may play an important role in this mutagenesis phase. Recently, DNA polymerase kappa (Polkappa), which belongs to the Y-family of DNA polymerases, was identified. Since a hot spot of SHMs (RGYW motif) is also a hot spot of mutations by human Polkappa, this enzyme was suggested to be an SHM instigator. In order to address the question whether Polkappa is involved in SHM, we immunized Polkappa-deficient mice and analyzed the SHM of the Ig heavy chain gene. We found that the SHM frequency and spectrum were indistinguishable between the Polkappa knockout mice and control mice. These results suggested that Polkappa is not essential for this process.     

Characteristics of cis-diamminedichloroplatinum-selected in vitro passaged cells derived from a transplantable rat malignant fibrous histiocytoma

A cis-diamminedichloroplatinum (CDDP)-selected cell line (MT-R10) was induced by continuous exposure of an in vitro passaged cell line (MT-P) established from a transplantable rat malignant fibrous histiocytoma (MFH-MT) to CDDP. MT-R10, capable of proliferating in the presence of 1.0 microgram CDDP/ml, was passaged in CDDP-free medium. The doubling time of MT-R10 at passage 10 (MT-R10/10) was almost the same as that of MT-P, being 22.3 and 25.5 h, respectively. The concentration of CDDP required for 50% inhibition of MT-R10/10 proliferation was two-fold higher than that of MT-P. MT-R10 consisted of round, epithelial-type cells arranged in compact sheets. Ultrastructurally, MT-R10 had numerous free ribosomes, some mitochondria, and other poorly developed cytoplasmic organelles suggesting its undifferentiated nature. MT-R10 showed no reaction for acid phosphatase or non-specific esterase. Tumors induced in syngeneic rats by inoculation with MT-R10 consisted of small, round, undifferentiated cells with scanty cytoplasm. They showed organoid and trabecular patterns, and were often arranged in compact sheets. The neoplastic cells showed no reaction for any of the histiocytic lysosomal and antigenic markers tested, but exhibited a strong reaction for alkaline phosphatase. Bone formation was often observed in the tumors. These observations suggest that CDDP-selected, undifferentiated cells may have osteogenic potential and may be one of the progenitor cells of MFH-MT.