An eight-year-old girl with autoimmune polyglandular syndrome type3A that developed during the course of primary Epstein-Barr virus (EBV) infection: clinical implication of EBV in autoimmune thyroid disease

An eight-year-old girl was admitted for prolonged fever and general fatigue. Bilateral reddened and swollen tonsils covered with white fur and increased numbers of atypical lymphocytes in blood led to a diagnosis of infectious mononucleosis (IM) due to primary Epstein-Barr virus (EBV) infection, which was confirmed by a positive anti-EBV viral capsid antigen IgM antibody reaction. She had a swollen thyroid gland and glycosuria at admission, which persisted after IM resolved. Undetectable thyroid-stimulating hormone (TSH), increased thyroid hormone and elevated HbA1c levels led to a diagnosis of autoimmune polyglandular syndrome type3A, based on the presence of antibodies for TSH receptor and glutamic acid decarboxylase. The clinical significance of EBV infection in the development of autoimmune endocrine disorders has been discussed.

Effects of combination therapy with a luteinizing hormone-releasing hormone agonist and chlormadinone acetate on rat prostate weight and plasma testosterone levels

We investigated whether the combination of chlormadinone acetate (CMA) and a luteinizing hormone releasing hormone (LH-RH) agonist, leuprorelin acetate (leuprorelin), more markedly decreased ventral prostate and seminal vesicle weights and plasma sex hormone levels in male rats. Four weeks after administration of 0.28, 0.84 or 2.8 mg/kg of leuprorelin, ventral prostate weights significantly decreased (53.8, 54.4 and 64.1%) and the plasma testosterone levels significantly lowered, but not dose-dependently. After repetitive administrations of 3 and 30 mg/kg/day of CMA, the rates of ventral prostatic atrophy were 37.1 and 65.9%, respectively. Although there was no change in the plasma testosterone level at 3 mg/kg, 30 mg/kg of CMA significantly decreased the level. A combination of leuprorelin (0.28 mg/kg) and CMA (3 or 30 mg/kg) more potently induced ventral prostatic and seminal vesicle atrophy than leuprorelin alone. Furthermore, a combination of leuprorelin and CMA (30 mg/kg) more markedly decreased the plasma testosterone level. According to the pharmacokinetic data for CMA in male rats, the doses of CMA correspond to the clinical dose. These findings suggest that combination therapy with an LH-RH agonist and CMA is more useful than therapy with the agonist alone in the treatment of prostate cancer.

Activation of cardiac ATP-sensitive K+ channels by KRN4884, a novel K+ channel opener

In the present study, we have investigated the mechanism underlying the activation by 5-amino-N-[2-(2-chlorophenyl)ethyl]-N'-cyano-3- pyridinecarboxamidine (KRN4884), a new K+ channel opener, of ATP-sensitive K+ (KATP) channels in single ventricular cells of guinea pig hearts by the inside-out patch-clamp method. In the presence of intracellular ATP (1 mM), KRN4884 (0.1-3 microM) activated KATP channels in a concentration-dependent manner (EC50 = 0.55 microM) without affecting the unitary current conductance and the gating properties. KRN4884 (0.3 microM) shifted the concentration-response relationship for ATP-induced KATP channel inhibition to the right and slightly upward direction without altering the slope. After either the spontaneous or Ca++-induced channel rundown, KRN4884 (1 and 3 microM) partially restored the KATP channel activity. Furthermore, the effect of KRN4884 was augmented by the presence of uridine 5'-diphosphate (3 mM). The results indicate that KRN4884 activates cardiac KATP channels through not only decreasing the sensitivity of the channel to ATP but also directly stimulating the opening of the channel.

Electrophysiological evidence of an increase in cold tolerance of cardiac muscles in mice after energy restriction

Life-prolonging energy restriction (ER) has been known to extend longevity. The heart was selected as the target organ of ER and the electrophysiological properties of ER on the heart were investigated. Action potential parameters were measured on ventricular papillary muscles of C57BL/6 mice (2-6 months of age). Resting membrane potential (Rm) did not change even when the temperature was lowered to 20 degrees C in ER mice (-67.5 +/- 0.8 mV), however, the membrane was depolarized in the control (-61.1 +/- 1.1 mV). Action potential duration measured at 30 and 50% repolarization was significantly prolonged in ER mice at 20-35 degrees C. Ouabain (10 microM) decreased Rm in ER mice at 20 degrees C (-68.6 +/- 1.0 to -63.6 +/- 0.8 mV), but failed to decrease Rm in the control (-60.6 +/- 1.8 to -62.1 +/- 1.2 mV). There were no significant differences in extracted Na, K-ATPase activity or affinity and binding capacity of ouabain between ER and control hearts. These results indicate that in ER mice the lack of effect of temperature on Rm was not due to a change in the physicochemical properties of Na, K-ATPase. The present study collectively suggests that ER increases cold tolerance in the heart of mice.

Potentiation by nitric oxide of the ATP-sensitive K+ current induced by K+ channel openers in guinea-pig ventricular cells

1. Modulation by nitric oxide (NO) of the ATP-sensitive K+ channel (KATP) current (IK(ATP)) was investigated in single ventricular cells dissociated from guinea-pig hearts. IK(ATP) was induced by 5-amino-N-[2-(2-chlorophenyl)ethyl]-N'-cyano-3-pyridinecarboxamidine+ ++ (KRN4884) and cromakalim. 2. In the whole-cell patch clamp configuration, KRN4884 (0.1 3 microM) increased the outward current in a concentration-dependent manner with an EC50 value of 0.48 microM. This current was completely antagonized by glibenclamide (1 microM). 3. IK(ATP) induced by either KRN4884 (0.3 microM) or cromakalim (10 microM) was significantly enhanced by the additional application of a NO donor (+/-)-(E)-ethyl-2-[(E)-hydroxyimino]-5-nitro-3-hexeneamide (NOR3, 0.1 and 1 mM). 4. The potentiating effect was observed only when NOR3 solution was prepared just before experiments, when release of NO was considered to be on-going. The effect was significantly eliminated in the presence of the NO scavenger oxyhaemoglobin (3 10 microM). Also, oxidative metabolites of NO, such as NO2 or NO3, were without effect. 5. 8-Bromo-guanosine-3':5'-cyclic monophosphate (8-Br-cyclic GMP, 0.1 0.5 mM) significantly decreased IK(ATP) induced by KRN4884. 6. In cell-attached patches, NOR3 (1 mM) potentiated the KRN4884-induced IK(ATP) in a way similar to that seen in whole-cell recordings. By contrast, NOR3 (1 mM) did not enhance the current in either inside-out or outside-out patches. 7. These results indicate that NO potentiates the action of K+ channel openers on the KATP through a mechanism which remains to be determined.

Cardiac effects of the novel pyridazinone derivative 6-[4-[2-[3-(5-chloro-2-cyanophenoxy)-2-hydroxypropylamino]- 2- methylpropylamino]phenyl]-4,5-dihydro-5-methyl-3(2H) pyridazinone monoethyl maleate and its metabolite in isolated heart preparations of guinea pigs and dogs

The cardiovascular effects of 6-[4-[2-[3-(5-chloro-2-cyanophenoxy)-2- hydroxypropylamino]-2-methylpropylamino]phenyl]-4,5-dihydro- 5-methyl-3(2H) pyridazinone monoethyl maleate (salt) (TZC-5665, CAS 114856-47-2) and its main metabolite in human, M-2, were investigated in isolated atrial and ventricular muscles of guinea pigs and dogs, in guinea pig atrial and right ventricular papillary muscles. TZC-5665 showed negative chronotropic and inotropic effects, whereas M-2 showed a potent positive inotropic effect with a slight positive chronotropic effect. The positive inotropic effect of M-2 was not modified by phentolamine, propranolol and cimetidine, but completely depressed by carbachol. In blood-perfused dog heart preparations, M-2 increased the contractile force and coronary blood flow of paced papillary muscles and sinus rate. Although TZC-5665 scarcely affected the contractile force and sinus rate, it increased coronary blood flow. TZC-5665 scarcely affected atrio-ventricular (AV) conduction time, whereas M-2 slightly shortened AV conduction time. The rate of ventricular automaticity was slightly increased by M-2, but suppressed by TZC-5665 at higher doses. TZC-5665 showed a non-selective beta-adrenoceptor blocking activity comparable to that of propranolol in guinea-pig atrial and tracheal preparations. In enzyme preparations, TZC-5665 and M-2 were more potent and selective inhibitors of phosphodiesterase (PDE) III than milrinone. Combination of beta-adrenoceptor blocking effect of TZC-5665 and positive inotropic effect of M-2 could be useful in the treatment of congestive heart failure by mutual prevention of undesirable effects.

Study on proteoglycans having low-sulfated chondroitin 4-sulfate in human urine and serum

State analysis of low-sulfated chondroitin 4-sulfate (LSC) in human urine and serum was performed by the use of high performance liquid chromatography and Western blot analysis. It was revealed that the most amount of LSC in urine is present as urinary trypsin inhibitor and a small amount (about 10% of total LSC) is as an LSC chain. The LSC in serum is mainly present as a proteoglycan such as inter-alpha-trypsin inhibitor (ITI), with a molecular weight of 212 kDa, but a small amount of LSC-proteoglycans having molecular weights of 128 and 38 kDa were also observed on SDS-PAGE. Those two compounds may be fragments of ITI, or one of the compounds (128 kDa) may be pre-alpha-trypsin inhibitor which was found by Enghild et al. (J. Biol. Chem., 264, 15975 (1989)).