Practical usage concentrations of monensin have non-specific actions other than as a sodium ionophore in rat parotid acinar cells.

Monensin is used as a sodium ionophore to examine the effect of Na+ on cellular function in a variety of cell types. In the present study, we investigated the effects of different concentrations of monensin on the signal transduction system in exocrine parotid acinar cells. Monensin increased cytosolic free Na+ concentration, measured by the Na+ indicator sodium-binding benzofuran isophthalate in a concentration-dependent manner (0.01 to 100 microM). Likewise, monensin concentration-dependently increased amylase release and intracellular Ca2+ concentration in the presence and the absence of extracellular Ca2+. Low concentrations (0.01 to 1 microM) of monensin did not release Ca2+ from non-mitochondrial intracellular pools in permeabilized cells with saponin but high concentrations (10 and 100 microM) of monensin which are of practical usage did. Monensin itself did not change the cyclic AMP accumulation, whereas high concentrations (10 and 100 microM) but not low concentrations (0.01 to 1 microM) of monensin inhibited cyclic AMP accumulation elevated by isoproterenol in the presence and absence of extracellular Na+. These results indicate that high concentrations of monensin, which are practically used, have nonspecific actions in rat parotid acinar cells, and lower concentrations of monensin are recommended for use as a sodium ionophore.     

Quantification of hydroxyl radical and its lack of relevance to myocardial injury during early reperfusion after graded ischemia in rat hearts.

To elucidate the pathophysiological role of the hydroxyl radical (.OH) during the postischemic reperfusion of the heart, we measured the .OH product in the coronary effluent from isolated perfused rat heart during a 30-minute reperfusion period after various ischemic intervals of 5, 10, 15, 20, 30, and 60 minutes. Salicylic acid was used as the probe for .OH, and its derivative, 2,5-dihydroxybenzoic acid (2,5-DHBA), was quantified using high-performance liquid chromatography with ultraviolet detection. 2,5-DHBA was negligible in the effluent from nonischemic hearts, but a significant amount was detected from the hearts rendered ischemic for 10 minutes or longer. The peak of 2,5-DHBA was seen within 90 seconds after the onset of reperfusion in every group. The accumulated amount of 2,5-DHBA was maximal in the group with 15-minute ischemia (6.73 +/- 1.04 nmol/g wet heart wt after 30 minutes of reperfusion); it decreased as the ischemic time was prolonged and was 2.38 +/- 0.84 nmol/g wet wt after 30 minutes of reperfusion in the group with 60-minute ischemia. In the model of 15-minute ischemia/30-minute reperfusion, there was no correlation between the accumulated amount of 2,5-DHBA and functional recovery (+/- dP/dt, heart rate, and coronary flow), lactate dehydrogenase release, and morphological damage. Although treatment with 0.5 mM deferoxamine, an iron chelator, significantly decreased 2,5-DHBA (from 6.73 +/- 1.04 to 2.29 +/- 0.80 nmol/g wet wt after 30 minutes of reperfusion, p less than 0.01), it failed to reduce the postischemic myocardial injury in the group with 15-minute ischemia. The results suggest that .OH production is influenced by the preceding ischemic interval and that .OH does not exert an immediate direct effect on postischemic damage during early reperfusion in the isolated perfused rat heart, although a possibility remains that the small portion of .OH trapped by salicylic acid may not be intimately associated with myocardial injury.     

High myocardial accumulation of radioiodinated digoxin derivative: a possible Na,K-ATPase imaging agent.

In view of the high binding ability of cardiac glycosides to the myocardial Na,K-ATPase, radioiodinated digoxin derivatives were surveyed as candidates for myocardial imaging, with particular emphasis on the noninvasive monitoring of cardiac glycoside therapy. Among the radioiodinated digoxin derivatives surveyed, 125I-digoxin-iodohistamine(bis(O-carboxymethyloxime)) showed the highest accumulation in the myocardium and similar binding ability to Na,K-ATPase as digoxin itself against ouabain displacement, as indicated by in vivo and in vitro studies. Based on these results, 123I labeling of digoxin-histamine(bis(O-carboxymethyloxime)) and imaging in a dog demonstrated uptake in the myocardium.     

Prevalence of post-polio syndrome based on a cross-sectional survey in Kitakyushu, Japan.

OBJECTIVES: To determine the number of polio survivors living in Kitakyushu, Japan, and the prevalence of post-polio syndrome. DESIGN: Cross-sectional survey in Kitakyushu. SUBJECTS/PATIENTS: A total of 342 possible polio survivors were selected from the list of physically disabled persons' certificates administered by the Department of Health and Welfare, Kitakyushu City Government. METHODS: A self-administered questionnaire concerning the diagnosis, paralysis, limitation in daily living, and use of adaptive devices was mailed to the 342 possible polio survivors. RESULTS: By confirmation of the diagnosis, 241 of the 342 turned out to be polio survivors, and the number of polio survivors per population of 100,000 amounted to 24.1. Of the polio survivors, 85% complained of new health problems such as difficulty in climbing stairs, muscle weakness, difficulty in walking, or fatigue. According to Halstead's criteria, 180 polio survivors suffered from post-polio syndrome, and the prevalence of post-polio syndrome in Kitakyushu was 18.0 per population of 100,000. CONCLUSIONS: This survey revealed the number of polio survivors, and the prevalence of post-polio syndrome in Kitakyushu, Japan.     

Cyclic mechanical stretching and interleukin-1alpha synergistically up-regulate prostacyclin secretion in cultured human uterine myometrial cells.

Prostacyclin (PGI2), a potent uterine smooth muscle relaxant, is postulated to be a major prostaglandin (PG) secreted from the human myometrium. PGI2 metabolite concentrations in the maternal plasma were reported to be elevated during pregnancy, especially during labor. Recently, we developed cultured human myometrial cells from pregnant women and reported that cyclic mechanical stretching mimicking labor increased PGI2 secretion from these cells by up-regulating PGI2 synthase promoter activities. Since elevation of cervical/vaginal interleukin-1alpha (IL-1alpha) concentrations is also a characteristic feature of delivery, and IL-1alpha is a known stimulator of PG synthesis, we investigated a possible synergistic effect of cyclic mechanical stretching and IL-1alpha on PGI2 production in cultured human myometrial cells. Treatment with IL-1alpha (10 ng/ml) significantly augmented (4- to 60-fold) the secretion of PGI2, prostaglandin E2 (PGE2), prostaglandin F2alpha (PGF2alpha) and thromboxane A2 (TXA2) from cultured human myometrial cells obtained from non-pregnant and pregnant women as well as in cultured human umbilical artery and cultured human coronary artery smooth muscle cells (p < 0.05 for all comparisons). However, labor-like cyclic mechanical stretching up-regulated IL-1alpha-augmented PGI2 secretion from myometrial cells obtained from non-pregnant and pregnant women 2.1- to 2.8-fold (p < 0.05 for all comparisons), but not PGE2, PGF2alpha nor TXA2. Moreover, such an augumentation of PGI2 secretion by cyclic mechanical stretching was not observed in cultured human umbilical artery nor in cultured human coronary artery smooth muscle cells. These results suggest that cyclic mechanical stretching by labor, in concert with IL-1alpha stimulation, contributes to the increase in myometrial PGI2 secretion during delivery.     

Ricinus communis agglutinin I blocks the binding of human anti-renal basement membrane antibodies to the kidney.

Whether or not glycosyl moieties of glycoproteins present in human renal basement membranes are related to the sites where anti-basement membrane antibodies bind was examined by blocking experiments using several kinds of lectin. Ricinus communis agglutinin I (RCA I), specific for galactose, blocked the binding of human anti-glomerular basement membrane (GBM) and anti-tubular basement membrane (TBM) antibodies to renal basement membranes. This lectin also diminished the binding of rabbit anti-laminin antibody, but did not inhibit the binding of mouse anti-fibronectin or rabbit anti-human TBM antibodies. These findings suggest that the binding sites of human anti-GBM and anti-TBM antibodies and heteroantibodies to laminin are closely related to the galactose moieties in glycoproteins of human renal basement membranes. Whether the galactose-containing branches are associated with the nephritogenicity of human anti-GBM and anti-TBM antibodies or simply exist adjacently to the antibody binding sites remains to be discerned.     

Characterization of a Helicobacter pylori neutrophil-activating protein.

Helicobacter pylori-associated gastritis is mainly an inflammatory cell response. In earlier work we showed that activation of human neutrophils by a cell-free water extract of H. pylori is characterized by increased expression of neutrophil CD11b/CD18 and increased adhesiveness to endothelial cells. The work reported here indicates that the neutrophil-activating factor is a 150,000-molecular-weight protein (150K protein). Neutrophil proadhesive activity copurified with this protein, which is a polymer of identical 15K subunits. Specific antibody, prepared against the purified 15K subunit, neutralized the proadhesive activity of the pure protein and of water extracts obtained from different strains of H. pylori. The gene (napA) for this protein (termed HP-NAP, for H. pylori neutrophil-activating protein) was detected, by PCR amplification, in all of the H. pylori isolates tested; however, there was considerable strain variation in the level of expression of HP-NAP activity in vitro. HP-NAP could play an important role in the gastric inflammatory response to H. pylori infection.     

CUSHING'S SYNDROME WITH BILATERAL MULTINODULAR ADRENAL HYPERPLASIA

An unusual case of Cushing's syndrome of a 59-year-old man with bilateral multinodular adrenal hyperplasia and microadenoma of the pituitary gland is presented. Failure to suppress plasma Cortisol with large doses of dexamethasone may suggest autonomous growth of hyperplastic nodules of the adrenals, which were at first induced by prolonged stimuli of ACTH from the microadenoma of the pituitary gland. ACTH could not be detected in the microadenoma cells on paraffin sections, while Crooke's cells were strongly positive for ACTH. The interrelation between bilateral multinodular adrenal hyperplasia and pituitary microadenoma is discussed.     

Ultrastructural,histochemical, and freeze-fracture evaluation of multilamellated structures in human pulmonary alveolar proteinosis

Ultrastructural, histochemical, and freeze-fracture studies of material recovered by bron-choalveolar lavage from patients with pulmonary alveolar proteinosis revealed four types (A, B, C, and D) of multilamellated structures (MS). Type A, the major component, consisted of concentric, trilaminar structures which were composed of two electron-dense layers and a central lucent layer (5.7–7.5 nm in overall width) alternating with wider (25–30 nm) electron-lucent intervening layers. Type B MS were formed by concentric lamellae with a 5–5.3-nm periodicity. Type C MS were composed of wavy, electron-dense lamellae with a 4–4.5-nm periodicity. Type D MS were conglomerated masses of intricately arranged double or triple electron-dense layers (7.5–13.5 nm wide) alternating with wider (30–40-nm) electron-lucent layers. The electron-dense lamellae of type A, type C, and type D MS were stained with ruthenium red, the Thiéry method, and concanavalin A, indicating the presence of carbohydrate components. Freeze-fracture studies revealed smooth inner and outer surfaces in type A MS, with the fracture planes passing through the central parts of the trilaminar structures; the intervening layers contained 10-nm particles, which probably are proteins. Type B MS had smooth surfaces, and type C MS had slightly particulate surfaces; while type D MS showed tubular or polygonal structures, 350 nm wide, with rows of particles 7–8 nm in diameter. It is concluded that type A and type D MS contain proteins and carbohydrates, probably in the form of glycoproteins, as well as phos-pholipids, and are related to tubular myelin. Type B and type C MS are considered to contain mainly phos-pholipids; type C MS are also considered to contain carbohydrates and to be related to lamellar bodies of type II alveolar epithelial cells.