Neurite outgrowth of PC12 cells is suppressed by wortmannin, a specific inhibitor of phosphatidylinositol 3-kinase

The effects of wortmannin (WT), an inhibitor of phosphatidylinositol (PI) 3-kinase, on differentiation of PC12 cells were analyzed. WT inhibited PI 3-kinase activity of PC12 cells at a concentration of 10(-7) M in vivo and in vitro. Transient inhibition of PI 3-kinase activity at the time of nerve growth factor stimulation had no effect on activation of the ras protein or neurite formation by the cells. However, continuous inhibition of PI 3-kinase blocked differentiation at the step just before neurite formation. When WT was applied to cells growing neurites, elongation of the neurites was stopped at that step. These results suggest that PI 3-kinase may be involved in neurite elongation.

Clobenpropit (VUF-9153), a new histamine H3 receptor antagonist, inhibits electrically induced convulsions in mice

The effect of clobenpropit (VUF-9153), a new histamine H3 receptor antagonist, on electrically induced convulsions was studied in mice. Clobenpropit significantly and dose dependently decreased the duration of each convulsive phase. Its anticonvulsant effects were prevented by pretreatment with (R)-alpha-methylhistamine and imetit (VUF-8325), histamine H3 receptor agonists. These findings suggest that the effect of clobenpropit on electrically induced convulsions is due to an increase in endogenous histamine release in the brain, which is consistent with biochemical results that clobenpropit increased brain histidine decarboxylase activity dose dependently. The anticonvulsive effect of clobenpropit was antagonized by mepyramine, a histamine H1 receptor antagonist, but not by zolantidine, a histamine H2 receptor antagonist, indicating that histamine released by the anticonvulsant effect of clobenpropit interacts with histamine H1 receptors of postsynaptic neurons. The present findings of the effect of clobenpropit on electrically induced convulsions are fully consistent with those of thioperamide as described previously (Yokoyama et al., 1993, Eur. J. Pharmacol. 234, 129), supporting the hypothesis that the central histaminergic neuron system is involved in the inhibition of seizures.

A reappraisal of the role of insulin-like growth factor I in the regulation of human hematopoiesis

IGF-I has been reported to increase hematopoietic progenitor cell cloning efficiency. To investigate this phenomenon, we studied the IGF-I responsiveness of human marrow cells expressing IGF-I receptor (IGF-IR), a direct strategy not used previously. IGF-IR+ and control CD34+ marrow cells were isolated using immunoaffinity methods. Then, the cells were cloned in methylcellulose containing variable amounts of serum- and lineage-appropriate growth factors supplemented with recombinant human IGF-I. In contrast to CD34+ cells, IGF-IR+ cells never gave rise to CFU-Blast, CFU-Mix, CFU-GM, BFU-E, or CFU-E. To substantiate the suggestion that CD34+ and IGF-IR+ cells were distinct populations, we used reverse transcription PCR to detect IGF-I, EpO, and KIT receptor mRNAs in these cells. The mRNA phenotype of CD34+ cells was EpO (+), KIT (+), and IGF-IR (-), while IGF-IR+ cells were IGF-IR (+), EpO (-), and KIT (-). These results suggested that IGF-IR is either not expressed or expressed at low levels on normal hematopoietic progenitor cells. Functional significance of the latter possibility was tested by exposing CD34+ cells to IGF-IR antisense oligodeoxynucleotides. Colony formation was unaffected by oligodeoxynucleotide disruption of IGF-IR, suggesting that, even if expressed at low level, the receptor's functional significance was doubtful. Nevertheless, when cultured in the presence of IGF-I, IGF-IR+ cells elaborated an activity with mild BFU-E stimulatory effects. Accordingly, if IGF-I plays a role in hematopoietic colony formation, it is probably and results from stimulation of IGF-IR-positive ancillary cells to secrete growth factors. Studies carried out with human leukemia cells yielded similar results.

A case of primary cystic mediastinal hemangiopericytoma

We describe a 35-year-old man with a primary cystic mediastinal hemangiopericytoma who presented with the complaint of progressive dysphagia for 6 months. The computed tomography and magnetic resonance imaging findings revealed that a well-defined, fluid-filled mass (measuring approximately 10 x 10 cm) was located posterior to the heart and inferior to the carina of the bronchus. Tumor puncture showed translucent yellow fluid with normal concentrations of carcinoembryonic antigen, squamous cell carcinoma-related antigen, and carbohydrate antigen 19-9 and a high concentration of carbohydrate antigen 125. After removal of the tumor, microscopic examination revealed a malignant hemangiopericytoma. To our knowledge, this is the first case of a primary mediastinal hemangiopericytoma with cystic formation. Moreover, we showed the specific biochemical findings of the cystic fluid that were useful for differentiation from other cystic mediastinal tumors.

The immunostimulant OK-432 enhances liver regeneration after 90% hepatectomy in rats

The effect of reticuloendothelial system activation on liver regeneration after 90% hepatectomy was investigated. OK-432, a killed streptococcal preparation that increases reticuloendothelial system activity, was administered to rats before 90% partial hepatectomy. Pretreated rats showed marked improvement in long-term survival: 87% (18 of 23) survived beyond 42 hr, compared with only 44.2% (24 of 52) of controls (p < 0.05). Survival was determined by means of life-table analysis and regeneration response by means of bromodeoxyuridine labeling index of hepatic DNA. OK-432 pretreatment had significantly increased bromodeoxyuridine labeling index 18, 24, and 42 hr after partial hepatectomy (p < 0.05). The results indicate that reticuloendothelial system activation by OK-432 before 90% partial hepatectomy enhances liver regeneration and improves survival, but these factors may not be related. The improved survival may be because of less infection in macrophage-stimulated animals or more rapid clearance of hypotension-causing vasoactive compounds.

A fully automated apparatus for a light/dark test measuring anxiolytic or anxiogenic effects of drugs in mice

We developed a fully automated light/dark apparatus which detects locomotion, rearing and time spent in light and dark zones, and shuttle crossing of mice. This apparatus is controlled by a personal computer and detects these parameters by using infrared beamsensors. We used this apparatus to investigate the effects of the anxiolytics, diazepam (DZP) and pentobarbital (PB); the putative anxiolytic, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT); and the anxiogenics, picrotoxin, methyl-beta-carboline-3-carboxylate (beta-CCM), and ethyl-beta-carboline-3-carboxylate (beta-CCE), on each parameter measured by a light/dark test in mice. DZP (5 mg/kg) and 8-OH-DPAT (0.1 and 0.2 mg/kg) significantly increased the time spent in the light zone. PB (10 mg/kg) also significantly increased the number of shuttle crossings between the dark and light zones. Conversely, picrotoxin (1 and 2 mg/kg) significantly decreased locomotion, rearing and time spent in the light zone. beta-CCM (10 mg/kg) and beta-CCE (5 mg/kg) also significantly decreased rearing and time spent in the light zone. Although the same dose of beta-CCE significantly decreased shuttle crossing and rearing in the dark zone, beta-CCE did not change locomotion in either zone. Our results indicate that this apparatus is useful for the assessment of the anxiolytic and anxiogenic activities of drugs in mice.

Three-dimensional structures of chimeric enzymes between Bacillus subtilis and Thermus thermophilus 3-isopropylmalate dehydrogenases

The 3-D structures of two chimeric enzymes (4M6T and 2T2M6T) between the Bacillus subtilis and Thermus thermophilus 3-isopropylmalate dehydrogenases were analysed by X-ray diffraction in order to investigate their different thermostabilities. The structure of 2T2M6T was determined by the difference Fourier method and that of 4M6T by rigid body refinement, as based on the structure of the T. thermophilus enzyme. These structures were refined stereochemically to an R-factor of 0.193 at 2.5 A resolution for 4M6T and to an R-factor of 0.195 at 2.2 A resolution for 2T2M6T. The 3-D structures of 4M6T and 2T2M6T were very close to the structure of the T. thermophilus enzyme, conspicuous differences being at the molecular surface. In particular, 2T2M6T having a larger reduction in thermostability was more closely related to the T. thermophilus enzyme. However, their correlations between C alpha-atom displacements and the root squares of the temperature factors were significantly different from each other.

2-Thiazolylethylamine, a selective histamine H1 agonist, decreases seizure susceptibility in mice

The effects of intracerebroventricular (ICV) administration of histamine and its selective agonists on electrically and pentylenetetrazole-induced convulsions in mice were studied. The ICV administration of histamine decreased seizure susceptibility on electrically and pentylenetetrazole-induced convulsions significantly and dose-dependently. The inhibitory effects of histamine were well antagonized by centrally acting histamine H1 antagonists such as pyrilamine (or mepyramine) and ketotifen, but not by a peripherally acting histamine H1 antagonist, astemizole, or a centrally acting H2 antagonist, zolantidine. The ICV administration of 2-thiazolylethylamine, a selective histamine H1 agonist, also decreased seizure susceptibility, which could be antagonized by centrally acting histamine H1 antagonists, whereas dimaprit, a selective histamine H2 agonist, did not affect seizure susceptibility. These findings strengthened the idea that the central histaminergic neuron system plays an inhibitory role in convulsions.

Cefotiam-induced IgE-mediated occupational contact anaphylaxis of nurses; case reports, RAST analysis, and a review of the literature

Cefotiam (CTM) is one of the most popular cephem antibiotics in Japan. Recently we experienced two cases of nurses with CTM-induced contact anaphylaxis. When they were preparing drip infusions of antibiotics or working around other nurses doing so, they suddenly fell into shock with other symptoms such as flushing, urticaria, abdominal distress, vomiting, dyspnoea and/or loss of consciousness. The symptoms never occurred after they avoided exposure to CTM. Passive cutaneous or open patch tests were positive for CTM. Histamine release was induced by CTM from washed leucocytes. RAST analysis using CTM-human serum albumin-coupled discs showed high % RAST count, suggesting that these reactions were mediated by IgE antibodies. A RAST inhibition test suggested that the methyl-thiotetrazole side-chain was the main antigenic determinant. Both patients had hand dermatitis that had appeared preceding the episodes of anaphylaxis. Although the dermatitis had been resistant to treatments, it also disappeared after they avoided exposure to CTM. It seemed likely that it was also induced or exacerbated by CTM and facilitated the penetration of CTM to cause anaphylaxis. The literature is also reviewed.

The orientation of primary cilia during the wound response in 3Y1 cells

The behavior of the primary cilia of 3Y1 cells in the interphase was investigated by indirect immunofluorescence microscopy and transmission electron microscopy, using an antibody for tubulin. At 4.5 h after scraping a part of a confluent cell sheet, the primary cilia of cells facing the wound were located predominantly forward of the nucleus on the wounded side, and were oriented in the direction of the leading lamellae. Cytoplasmic microtubules (MTs), emanating from around the base of the cilia, were well developed in the leading lamellae on the wounded side. On the other hand, in the cells of an unperturbed area away from the wounded edge, the primary cilia remained randomly distributed near the nucleus. The position and a certain well-defined orientation of a pair of centrioles seem to play an important role for the development of cytoplasmic MTs, and consequently the orientation of the centrioles is controlled by the primary cilia.

Plasma peroxidized low-density lipoprotein with hydroperoxidized cholesteryl linoleates estimated in patients with familial hypercholesterolemia

A study was conducted to ascertain the presence of peroxidized low-density lipoprotein (LDL) in plasma and to determine the chemical structure of the peroxidized LDL so that the mechanism by which vascular complications develop may be elucidated in patients with familial hypercholesterolemia (FH). Family trees showing hypercholesterolemia and moderate grade thickness of the Achilles' tendon were confirmed in all patients. Cholesteryl ester, triglycerides (TG), free fatty acid (FFA), free cholesterol (FC), and phospholipids in normal LDL were stained on a thin-layer chromatography (TLC) plate, but from peroxidized LDL, spot X1 between TG and FFA, and spot X2 between FFA and FC were identified clearly except for the lipids recognized in normal LDL on the TLC plates. From intermediate-density lipoprotein (IDL), LDL1, and LDL2 of FH patients, spot X1 was clearly recognized. Hydroperoxidized cholesteryl linoleate (HPO-CL) was estimated and identified from Cu(2+)-treated standard CL, Cu(2+)-treated LDL and LDL obtained from FH patients by means of high-pressure liquid chromatography, mass spectrometry, nuclear magnetic resonance, positive reaction of p-methoxydiphenylpyrenyl-phosphine and various chemical reactions. The percentage of HPO-CL to total lipids in LDL was in the order of IDL < LDL1 < LDL2 in FH patients, and it was markedly higher in FH patients when compared to healthy persons. Spot X1 obtained from Cu(2+)-treated CL, from Cu(2+)-treated normal LDL and from LDL of FH patients was chemically identical, consisting of at least 4 kinds of HPO-CL isomer. LDL2-cholesterol levels were higher in FH patients than those of LDL1-cholesterol, whereas in healthy persons LDL1 cholesterol levels were higher compared to those of LDL2 cholesterol. The capacity of LDL2 for peroxidization by Cu2+ was greater than that of LDL1 in healthy persons. Biological functions, such as acceleration of platelet aggregation, great internalization into macrophages and injuries of the arterial endothelia, were reported for LDL with HPO-CL in our previous experiments. Thus, the existence of peroxidized LDL with HPO-CL may be one of the important risks for vascular complications in FH patients.

The differential effects of histamine receptor antagonists on morphine- and U-50,488H-induced antinociception in the mouse

The effects of thioperamide, an H3 antagonist, and histamine H1 and H2 antagonists (s.c.) on morphine (s.c. or i.c.v.)- and U-50,488H (i.c.v.)-induced antinociception in male ddY mice were examined using the hot-plate (55 degrees C) test. Thioperamide significantly inhibited morphine-induced antinociception, but not U-50,488H-induced antinociception. The suppressive effect of thioperamide on morphine-induced antinociception was reversed by the H1 antagonist pyrilamine, but not by the H2 antagonist zolantidine. On the other hand, pyrilamine significantly potentiated the antinociception induced by morphine, but not that induced by U-50,488H. Zolantidine significantly inhibited morphine-induced antinociception in a dose-dependent manner, but not U-50,488H-induced antinociception. Both astemizole, an H1 antagonist, and ranitidine, an H2 antagonist, which are known to barely cross the blood brain barrier, did not affect morphine-induced antinociception. These results suggest that morphine-induced antinociception may be potentiated by activation of H2 receptors and suppressed by activation of H1 receptors in the brain. Furthermore, neuronal histamine release induced by thioperamide may suppress morphine-induced antinociception through H1 receptors.

Detection of Epstein-Barr virus DNA and EBV-determined nuclear antigen in angioimmunoblastic lymphadenopathy with dysproteinemia type T cell lymphoma

Six cases of angioimmunoblastic lymphadenopathy with dysproteinemia (AILD)-like T cell lymphoma were analyzed by immunohistochemical staining, polymerase chain reaction (PCR) and Southern blot analysis. Five cases out of six showed gene rearrangements of the T cell receptor beta chain, indicating the existence of a clonal T cell proliferation. Epstein-Barr virus (EBV) DNA was detected in all six AILD type cases by PCR amplifying the sequence located in the internal repeat I, and confirmed by Southern blot hybridization, using a BamHI-W fragment as a probe. Detection of the EBV genome occurred more frequently as compared with other types of lymphoid disorders. Furthermore, EBV determined nuclear antigen (EBNA) was detected in UCHL-1 (CD45RO, pan-T cell marker) positive cells by immunostaining. These results suggest that a significant number of AILD type cases are T cell origin lymphomas and EBV infection may be relevant to the biological features of this type of lymphoma.

Clinical significance of DNA measurements in small cell lung cancer

BACKGROUND

Little is known about the relationship between DNA histogram data and the clinical course of small cell lung cancer (SCLC).

METHODS

The ability of tumor nuclear DNA histograms as measured by cytofluorometry to predict chemotherapeutic responsiveness and propensity for metastases was assessed in 36 patients with SCLC. Histograms were classified into four types: A, mono-mode and euploid; B, mono-mode but not euploid (A + B being monoclonal patterns); C, poly-mode; and D, no mode (C + D being polyclonal patterns). The grade was classified into low (DNA content, smaller than 8C) and high (greater than 8C) by dispersion degrees about each type.

RESULTS

The relative rate of response to chemotherapy was A (100%) is greater than B (82%) is greater than C (38%) is greater than D (17%) (A and D, P < 0.05; B and D, P < 0.01; A + B and C + D, P < 0.01) and closely related to type. Metastasis rates were significantly different between high (81%) and low (7%) grade (P < 0.01) and closely related to grade (sensitivity, 81%; specificity, 93%). Peripheral SCLC had a significantly lower response rate (20%) than did proximal SCLC (65%) (P < 0.01). In DNA histograms, the proportion of C + D (more heterogeneous than A+B) was significantly higher (80%) in peripheral SCLC (P < 0.01).

CONCLUSIONS

Nuclear DNA measurements may be potentially useful for predicting distant metastases and response to chemotherapy. The heterogeneity and possibility of resistance to chemotherapy of peripheral SCLC may tend to be higher than those of proximal SCLC.

Characterization of lung squamous cell carcinoma-derived T-cell suppressive factor

BACKGROUND

The immunosuppressive state of a tumor-bearing patient is possibly mediated by tumor-derived factor. In this study, the authors characterized lung squamous cell carcinoma-derived immunosuppressive factor (LSCF).

METHODS

The immunosuppressive activity of QG56 (a lung squamous carcinoma cell line)-derived LSCF was evaluated by the effect of culture supernatant of QG56 on anti-CD3 monoclonal antibody-induced T-cell, response such as proliferation (3H-thymidine uptake), cytotoxicity (51Cr-releasing assay), and expression of cytokine mRNA (polymerase chain reaction). The LSCF was partially purified with an ion-exchange high-performance liquid chromatography (HPLC) and a gel-filtration HPLC.

RESULTS

The LSCF inhibited proliferation, cytotoxicity, and expression of cytokine mRNA of T-cells in a dose-dependent manner. It has a molecular weight of approximately 22 kd, and was sensitive to proteinase K, heating at 60 degrees C, and resistant to treatment with trypsin and pH 3 and 9. These properties appear to be similar to those of transforming growth factor-beta (TGF-beta). However, the activity of the LSCF was not abrogated by anti-TGF-beta sera, and the LSCF did not suppress the proliferation of TGF-beta-sensitive mink lung cells (Mv1Lu).

CONCLUSIONS

These data suggest that LSCF may be a novel tumor-derived immunosuppressive protein factor.

MK-801 and dopaminergic system in electrically-induced convulsions in mice

In this study, the effects of MK-801 and selective dopaminergic agents on electrically-induced convulsions in mice were examined. MK-801 (0.004-0.1 mg/kg, ip) showed significant and dose-dependent anticonvulsive effects, and the anticonvulsive effects of MK-801 (0.02 mg/kg, ip) were not antagonized by dopamine selective antagonists, SCH-23390 (D1, 0.1 mg/kg, sc), sulpiride (D2, 100 mg/kg, sc) and pimozide (D2, 0.5 mg/kg, sc). Apomorphine (0.02-0.5 mg/kg, sc), a D1/D2 agonist, showed proconvulsant effect on electrically-induced convulsions. Dopamine selective antagonists, SCH-23390 (0.02-0.5 mg/kg, sc), sulpiride (5-100 mg/kg, sc) and pimozide (0.1-2.5 mg/kg, ip), also showed proconvulsant effect. However, these effects of dopamine agonist and antagonists were not dose-dependent. These findings suggest that the dopaminergic system neither plays an inhibitory role, at least on electrically-induced convulsions in mice, nor contributes to the anticonvulsant effect of MK-801 in electrically-induced convulsions.