Involvement of the interleukin-2 receptor gamma subunit in interleukin-4-dependent activation of mouse hematopoietic cells and splenic B cells

Interleukin-4 (IL-4) has various activities on B cells and on hematopoietic cells. We previously reported that TUGm2, a monoclonal antibody to the gamma subunit of the IL-2 receptor (IL-2R gamma), inhibited IL-4-dependent proliferation of CTLL2, a cytotoxic T cell line. We proposed that IL-2R gamma is required for the functional IL-4 receptor (IL-4R) in T cells. In the present work, we further examined whether or not IL-2R gamma is involved in IL-4R function in mouse myeloid cell lines and splenic B cells. TUGm2 suppressed the IL-4-induced proliferation of BA/F3 or IC2 cells, as well as of purified splenic B cells. TUGm2 partially suppressed proliferation of B cells induced by the combination of IL-4 and anti-immunoglobulin M (IgM) antibody. In contrast, TUGm2 had no effect on proliferation of B cells induced by anti-IgM antibody alone or lipopolysaccharide (LPS). TUGm2 also inhibited IgE production induced by IL-4 of LPS-stimulated B cells. The induction of major histocompatibility complex class II molecules or CD23 by IL-4 was virtually unaffected by TUGm2 antibody. These results indicate that IL-2R gamma is differentially involved in various IL-4-dependent reactions.

Hydroxyl radical scavenging by rebamipide and related compounds: electron paramagnetic resonance study

We studied the scavenging activity of rebamipide, a novel antipeptic ulcer agent, and seven related compounds against hydroxyl radicals using the electron paramagnetic resonance (EPR) spin trapping technique. 5,5-Dimethyl-1-pyrroline-N-oxide (DMPO) was used as a spin trapping agent. We estimated the second order rate constant for the reaction between the agents tested and hydroxyl radical at pH 7.8 by kinetic competition studies. All compounds tested scavenged the hydroxyl radicals with a certain relationship between concentration and scavenging efficacy. A structure-scavenging activity relationship was derived from the kinetic evidence available on the formation and inhibition of the DMPO spin adduct EPR signal of hydroxyl radicals (DMPO-OH). Important determinants for scavenging hydroxyl radicals were the 3,4-double bond of the quinolinone ring in conjunction with a 2-oxo function and the carbonyl portion of the amido group in conjunction with a para-chlorobenzoyl function.

[A case of acute sensory neuropathy]

We report a 50-year-old man who developed sensory neuropathy of acute onset. It affected position and vibration senses very severely, and superficial sensations mildly. There were athetoid movements of the outstretched left arm when the eyes were closed. The upper limbs were more severely affected than the lower limbs. There was no weakness or atrophy in the limb muscles. Nerve conduction study and somato-sensory evoked potential showed normal function of motor nerves and axonopathy of the sensory nerves. Sural nerve biopsy disclosed fibrosis and marked loss of myelinated fibers, especially of large ones, and many fibers with myelin balls in teased preparations, indicating severe axonopathy. Electronmicroscopy confirmed severe degeneration and loss of myelinated axons with abundant myelin figures in schwann cells. There were no malignancy or other diseases that could cause sensory neuropathy, and he was diagnosed as having acute sensory neuropathy (ASN) of Windebank et al. ASN, a distinct syndrome characterized by axonal type neuropathy, should be segregated from acute and chronic inflammatory demyelinaiting neuropathies although the clinical features and CSF findings look alike.

Elevated anti-neutrophil cytoplasmic antibody titer in a patient with atypical orbital pseudotumor

We recently examined a patient with ophthalmic manifestations of Wegener's granulomatosis in whom antineutrophil cytoplasmic antibody (cANCA) titers provided helpful diagnostic information. A 40-year-old man who had suffered from bilateral exophthalmos for 9 months was diagnosed initially as having idiopathic inflammatory pseudotumor. The patient exhibited purulent nasal discharge and microhematuria. A histopathologic study revealed vasculitis. His ANCA titer for cANCA was found to be evaluated, and our patient was subsequently diagnosed as having Wegener's granulomatosis. His ocular symptoms resolved and did not recur after treatment with corticosteroid in combination with cyclophosphamide. We believe that cANCA levels should be investigated in patients with orbital pseudotumor as a possible sign of Wegener's granulomatosis.

Sharing of the IL-2 receptor gamma chain with the functional IL-9 receptor complex

The third subunit, the so-called common gamma (gamma c) chain, of the IL-2 receptor is shared among the receptors for IL-2, IL-4, IL-7 and IL-15, and dysfunction of the gamma c chain is thought to cause X-linked severe combined immunodeficiency (XSCID) ascribed to impairment of early T cell development. However, cytokines linked to XSCID are as yet unidentified. A mAb specific for the gamma c chain, TUGm2, profoundly inhibited cell proliferation in response to IL-9. Another mAb, TUGm3, immunoprecipitated [125I]IL-9 cross-linked with either the IL-9 receptor or the gamma c chain. These results demonstrate that the gamma c chain is included in the functional receptor complex for IL-9, which was initially characterized as a T cell growth factor and is essential for IL-9-dependent growth signal transduction.

IL-2 can support growth of CD8+ T cells but not CD4+ T cells of human IL-2 receptor beta-chain transgenic mice

We have generated transgenic mice expressing the human (h) IL-2R beta-chain on lymphoid cells under the control of the mouse H-2Kd promoter. Spleen cells and thymocytes of the transgenic mice were cultured in the presence of 5 nM hIL-2. After a 10-day culture, the expanded populations were analyzed by flow cytometry and shown to be composed of CD8+ T cells and gamma delta T cells. Surprisingly, CD4+ T cells of the transgenic mice did not proliferate in response to hIL-2, although the CD4+ T cells expressed the transgenic hIL-2R beta-chain as well as the endogenous gamma-chain on their surface and bound 125I-labeled IL-2. When CD4+ T cells of the transgenic mice were stimulated with anti-CD3 mAb, the CD4+ T cells proliferated in response to hIL-2. These findings suggest that CD4+ T cells may require another triggering signal to respond to IL-2 even when IL-2Rs are expressed. By contrast, CD8+ T cells and gamma delta T cells respond to IL-2 as long as IL-2Rs are expressed.

IL-2 can support growth of CD8+ T cells but not CD4+ T cells of human IL-2 receptor beta-chain transgenic mice

We have generated transgenic mice expressing the human (h) IL-2R beta-chain on lymphoid cells under the control of the mouse H-2Kd promoter. Spleen cells and thymocytes of the transgenic mice were cultured in the presence of 5 nM hIL-2. After a 10-day culture, the expanded populations were analyzed by flow cytometry and shown to be composed of CD8+ T cells and gamma delta T cells. Surprisingly, CD4+ T cells of the transgenic mice did not proliferate in response to hIL-2, although the CD4+ T cells expressed the transgenic hIL-2R beta-chain as well as the endogenous gamma-chain on their surface and bound 125I-labeled IL-2. When CD4+ T cells of the transgenic mice were stimulated with anti-CD3 mAb, the CD4+ T cells proliferated in response to hIL-2. These findings suggest that CD4+ T cells may require another triggering signal to respond to IL-2 even when IL-2Rs are expressed. By contrast, CD8+ T cells and gamma delta T cells respond to IL-2 as long as IL-2Rs are expressed.

Effect of CL 316,243, a novel beta 3-adrenoceptor agonist, on insulin secretion in perfused mouse pancreas

In order to clarify the insulin-release mechanism of beta 3-adrenoceptor agonist, we examined the effect of CL 316,243, a highly specific beta 3-adrenoceptor agonist having a relative potency of beta 1:beta 2:beta 3 = 0:1:100,000, on insulin secretion in perfused mouse pancreas. The application of 0.2 mM and 0.5 mM CL 316,243 produced significant insulin secretion from within 1 min, which lasted until 2 min after its withdrawal. DL-propranolol and ICI 118551 at 0.2 mM partially inhibited the insulin secretion induced by the 0.2 mM CL 316,243, but 0.2 mM metoprolol had no effect on the insulin release produced by 0.2 mM CL 316,243. We conclude that beta 3-adrenoceptor agonist stimulates insulin secretion via beta 3-action in the perfused mouse pancreas.

[Continuous monitoring of nitric oxide release from airway mucosa]

There is increasing evidence that nitric oxide (NO) plays a role in the regulation of airway and vascular smooth muscle tone, pulmonary microvascular permeability, and host defense. However, it remains uncertain whether NO is actually released from airway mucosa. We therefore directly measured NO concentrations in the perfusate of rabbit tracheal mucosal surface, with an NO-selective electrode. The electrode was made of Pt/Ir alloy coated with a three-layered membrane that consisted of KCl, No-selective silicone resin, and a normal silicone membrane. Termination of tracheal perfusion with Krebs-Henseleit solution increased the electrical current derived from oxidation of NO at the electrode, and reperfusion rapidly decreased the current to the baseline value. Addition of L-NG-arginine methylester (L-NAME, 10(-3) M) to the perfusate decreased NO release, but D-NAME had no effect. Subsequent addition of L-arginine (10(-3) M) reversed the inhibition by L-NAME and greatly increased NO release above the baseline value. Histochemical staining to reveal NADPH diaphorase activity in the tracheal tissue showed a strong blue reaction mainly in the epithelial cells. These results suggest that NO is continuously released in the airway mucosal surface, probably from the epithelial cells rich in NO synthase.

Mechanism of anti-obesity action of benidipine hydrochloride in mice

Benidipine hydrochloride, a dihydropyridine calcium antagonist, decreases body weight and also has a hypotensive effect. The mechanism of its inhibitory effect on body weight is unclear, although this agent increases blood flow in brown adipose tissue, which functions as a main thermogenic organ. The hypothesis that benidipine hydrochloride activates brown adipose tissue to induce body weight loss was tested on mice made obese by pretreatment with monosodium-L-glutamate (MSG). When benidipine hydrochloride was incorporated in the diet (1.0 mg per gram of food) for 4 weeks, binding of guanosine-5'-diphosphate in brown adipose tissue mitochondria was significantly increased. Body weight and body fat decreased in both MSG obese mice and in lean controls. Results support the hypothesis and suggest the possibility that benidipine hydrochloride may be useful for treating obese hypertensive patients.

[Pharmacokinetic and clinical studies of cefozopran in the field of pediatrics]

Pharmacokinetic and clinical studies on cefozopran (CZOP, SCE-2787), a new cephalosporin antibiotic, were carried out in the field of pediatrics. The results obtained are summarized below. 1. Serum concentrations and urinary excretion rates were determined after intravenous bolus injection of CZOP at a dose of 20 mg/kg for 5 minutes in 3 cases. The mean serum concentration of CZOP was 45.9 micrograms/ml at 30 minutes with the serum half-life of 1.77 hours. The mean cumulative urinary excretion rate in the first 8 hours after administration was 71.4%. 2. Fourteen patients with bacterial infections (pneumonia 9 cases, urinary tract infection 4 cases and lymphadenitis 1 case) were treated with CZOP at a daily dose of 55.8-65.7 mg/kg. The overall clinical efficacy and bacteriological eradication rates were both 100%. 3. No adverse reactions were observed. Abnormal laboratory test results were mild, slight elevation of GOT and GOT, GPT & LDH in 1 each and eosinophilia and thrombocytosis in 2 cases each.

[Cell-to-cell interaction in airway mucosa--effect of eosinophils on airway epithelial ion transport]

We examined the interaction between eosinophil-derived mediators and ion transport in airway epithelial cells. Eosinophils were obtained by peritoneal lavage from polymyxin B-treated guinea-pigs and were purified over discontinuous Percoll density gradients. The activated eosinophil supernatant was prepared with a two-stage method in the presence of A23187. The effects of eosinophil supernatant on the electric properties of cultured epithelial cells from cow trachea were examined in an Ussing chamber under short-circuit conditions. The eosinophil supernatant added to the serosal and mucosal sides increased the short-circuit current (Isc) in an eosinophil number-dependent manner (3 x 10(6), 10(7) eosinophils: delta Isc 9 +/- 1 microA/cm2, 18 +/- 3 microA/cm2). The response was inhibited by treatment of epithelial cells with diphenylamine-2-carboxylate but not by amiloride. The increase in Isc induced by the supermatant from eosinophils treated with indomethacin or the lipoxygenase inhibitor AA861 was significantly less than that induced by untreated eosinophils. These results indicate that activated eosinophils stimulate C1 secretion in airway epithelium via release of metabolites of arachidonic acid.

Antitumor effect of ischemia-reperfusion injury induced by transient embolization

The effect of ischemia-reperfusion, induced by the transient embolic agent degradable starch microspheres (DSMs) on tumor tissue was investigated from the standpoint of active oxygen species. Rabbits with VX2 carcinoma received regional infusion of DSMs by transcatheter angiography, and it was confirmed that DSMs occluded tumor vessels. Blood flow in the tumors decreased rapidly immediately after the DSM treatment and returned to the original level within 40 min. The size of tumors did not change after a single infusion of DMS, while five repeated DSM treatments led to a significant reduction in tumor size. This reduction in tumor size was prevented by the treatment of rabbits with superoxide dismutase and catalase, indicating that the generation of active oxygen species in the tumor was involved in the mechanism of action of DSMs. Thiobarbituric acid-reactive substances also increased in the tumors after DSM infusion, and this increase was also inhibited by treatment with superoxide dismutase and catalase. In conclusion, the antitumor effect of the transient embolic agent DSM is secondary to the phenomenon of ischemia-reperfusion injury. In addition, active oxygen species and lipid peroxidation are possible causes of ischemia-reperfusion injury.