L-NG-monomethyl arginine inhibits the vasodilating effects of low dose of endothelin-3 on rat mesenteric arteries

We have reported that low doses of endothelin-3 (ET-3) elicited continuous vasodilation of rat mesenteric arteries, which is possibly related to endothelium-derived relaxing factor (EDRF). In order to clarify whether or not the vasodilating effects of ET-3 are associated with EDRF, we examined the effects of L-NG-monomethyl arginine (L-NMMA), an analog of L-arginine, on low-dose ET-3 induced vasodilation of rat mesente-Hc arteries. Infusion of 50 microM L-NMMA inhibited the vasodilation induced by 10(-13) M ET-3 and rather elicited an increase in perfusion pressure, which itself was decreased by infusion of 150 microM L-arginine. In the presence of 50 microM L-NMMA, 10(-13) M ET-3 did not elicit any vasodilation of the mesenteric arteries preconstricted with NE, in which 150 microM L-arginine, but not D-arginine, caused considerable vasodilation. These data suggest that the vasodilating effects of low doses of ET-3 are associated with EDRF as an endothelium-derived nitric oxide.

Effect of atrial natriuretic peptide on adrenal renin and aldosterone

The effect of atrial natriuretic peptide (ANP) on adrenal renin and aldosterone was investigated in anesthetized rats. Under pentobarbital anesthesia 40 mg/kg), intravenous infusion of ANP (0.25 micrograms/kg/min) for 45 min failed to alter the adrenal renin, adrenal aldosterone, and plasma aldosterone (PA). In this condition, intraperitoneal injection of ACTH (10 micrograms/kg) significantly increased the adrenal renin (from 2.4 +/- 0.1 to 5.0 +/- 0.08 ng/mg protein/h, P less than 0.05), adrenal aldosterone (from 13.6 +/- 1.3 to 22.7 +/- 2.3 ng/mg protein, P less than 0.01) and PA (from 59.8 +/- 5.8 to 75.5 +/- 7.4 ng/dl, P less than 0.05), respectively. Under ACTH stimulation, ANP infusion induced significant decreases in adrenal renin (from 5.0 +/- 0.08 to 2.8 +/- 0.2 ng/mg protein/h, P less than 0.05), adrenal aldosterone (from 22.7 +/- 2.3 to 16.2 +/- 1.8 ng/mg protein, P less than 0.05) and PA (from 75.5 +/- 7.4 to 61.6 +/- 4.9 ng/dl). These results suggest a possible role for adrenal renin in the mechanism underlying the inhibitory effect of ANP on aldosterone production in vivo.

[A comparative study of C19 steroid-induced hypertension and deoxycorticosterone acetate (DOCA)-salt hypertension]

In order to evaluate the hypertensinogenic action of 19-hydroxyandrostenedione (19-OH-AD), which has been reported to be an amplifier of mineralocorticoid, the changes in several humoral factors were observed in 19-OH-AD treated rats as compared to those in DOCA hypertensive rats. Twenty-five male Wistar rats were castrated at 11 weeks of age, and the experiments were begun at 12 weeks of age. The rats were divided into 3 groups. The control group (n = 8) was given an s.c. injection of 0.2 ml of sesame oil. The 19-OH-AD group (n = 10) was injected s.c. with 10 mg of 19-OH-AD dissolved in 0.2 ml of sesame oil, and the DOCA group (n = 8) was injected s.c. with 10 mg of DOCA dissolved in 0.2 ml of sesame oil three time weekly. The urine was collected for a period of 24 hours, and the urine volume, and urinary excretions of electrolytes, prostaglandin E2 (PGE2), kinin and catecholamine were measured before and after the start of the experiment. The systolic blood pressure (S.B.P.) was measured by the tail-cuff method. The S.B.P. values before and at 9 weeks after the start of the experiments were 136.7 +/- 3.8 and 156.0 +/- 2.6 mmHg in the 19-OH-AD group, and 140.6 +/- 5.6 and 179.3 +/- 5.5 mmHg in the DOCA group, respectively. Body weight, which was elevated in both groups, was higher in the 19-OH-AD group than in the DOCA group. Water intake and urine volume were significantly (p less than 0.001) increased only in the DOCA group. The urinary Na/K ratio was significantly (p less than 0.001) elevated in the DOCA group as compared to that in the other two groups. However, there was no significant difference in urinary Na/K ratio between the control and 19-OH-AD groups. The urinary PGE2 and kinin excretions were significantly (p less than 0.01) increased in the DOCA group but did not change appreciably in the 19-OH-AD group. The urinary catecholamine excretion was significantly increased in the DOCA group. However, there were no differences in the catecholamine excretion between the control and 19-OH-AD groups.(ABSTRACT TRUNCATED AT 400 WORDS)

Electron spin resonance studies of wild-type and mutant cytochromes P-450d: effects of mutations at proximal, aromatic and distal sites on g values

Low-temperature (6-40 K) electron spin resonance (ESR) spectra of cytochrome P-450d (P-450d) and its 17 mutants have been measured. The spectra of the wild-type and all mutant P-450ds showed signals at around g = 8, 3.7 and 1.7, while they didn't show any signal at around g = 2 up to 40 K. It was thus suggested that all of these P-450ds essentially take the ferric high-spin form. The g values of the proximal mutants were closer to those of the wild-type than those of the distal and aromatic mutants, suggesting that mutations at the distal and aromatic sites influence the electronic state of the heme more profoundly than those of the proximal site. The distal multiple mutants whose distal sequences are the same as those of the low-spin type P-450s such as rat P-450c, mouse P1-450 and P3-450 showed only high-spin ESR signals. Thus the spin state of P-450ds (the wild-type and all mutants) may not be solely due to specific characteristics of the distal site, but to the unique nature of the whole heme environment of P-450d. It is also suggested that the amino acids at the distal region of P-450d may be located close to the heme, so that the water molecule cannot bind to the heme, thus taking the high-spin state. Both the aromatic mutants showed rather large deviations of the g values from those of wild-type P-450d, suggesting that the aromatic region somehow interacts with the heme.

[Valvular regurgitation in patients with complete heart block by color Doppler echocardiography]

We studied valvular regurgitation (pulmonary, aortic, tricuspid and mitral regurgitation) in 30 patients with complete heart block by color Doppler echocardiography, pulse Doppler and continuous wave Doppler echocardiography. The prevalence rate of multivalvular regurgitation of these subjects was 83.3%. Regurgitation involving all four valves appeared in 30.0% of these patients. The prevalence rate of pulmonary, aortic, tricuspid and mitral regurgitation was 56.7%, 33.3%, 100%, and 76.7% respectively. Pulmonary regurgitation (PR) was observed in patients with complete heart block without pulmonary hypertension. PR velocity was slow and interrupted by atrial contraction. It might be possible to evaluate atrial pressure from the interruption of PR. Tricuspid regurgitation (TR) during systole was often present in patients with right ventricular endocardial pacing. Systolic TR was influenced by atrial contraction. When atrial contraction occurred during systole, TR was interrupted, or shortened. Diastolic TR and MR were easily detected by M mode color Doppler echocardiography. The diastolic TR and MR were of slow velocity and appeared 240-290 msec after P wave. These atypical valvular regurgitation in patients with complete heart block reflect of the inverse atrial-ventricular pressure gradient across the atrio-ventricular valve.

Adenylate cyclase activities of vascular smooth muscle in early and established DOCA/salt hypertensive rats

It has been demonstrated that the adenylate cyclase activity of vascular smooth muscle regulates its tonus. The present study was undertaken to examine adenylate cyclase activity in early and established deoxycorticosterone acetate (DOCA)/salt hypertensive rats. Early and established DOCA/salt hypertensive rats were prepared by injecting 30 mg of DOCA weekly for 3 and 10 weeks, respectively, into male Wistar rats given drinking water with 1% saline. The membrane protein fraction medium containing the protein, 50 microM isoproterenol, 100 microM GTP, 50 microM forskolin or 25 microM calmodulin was applied. The adenylate cyclase activity was determined by a modified method developed in our laboratory using double isotope counting. The adenylate cyclase activity in the early DOCA/salt hypertensive rats was significantly higher (p less than 0.05) than that in the control rats in the basal condition, which was unaffected by additions of isoproterenol, GTP or forskolin. There was no significant difference in basal adenylate cyclase activity between the established DOCA/salt hypertensive and control rats. The adenylate cyclase activities in the established DOCA/salt hypertensive rats were significantly lower with GTP (p less than 0.02) and forskolin (p less than 0.01) as compared with the control rats. Calmodulin elevated the adenylate cyclase activity significantly (p less than 0.05) in the established DOCA/salt hypertensive rats as well as in the control rats. However, enzyme activity with calmodulin in the established DOCA/salt hypertensive rats was significantly lower (p less than 0.05) than that in the control rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Monoclonal anti-human C3d antibodies: stabilization of the alternative pathway C3 convertase

IgG mouse monoclonal antibody (mAb) was prepared by fusion of spleen cells from mice immunized with human C3d (mAb:C3d) using syngeneic thymocytes as feeder cells. mAb:C3d was assessed for its effect on the stabilization of the cell-bound alternative pathway C3 convertase EAC3bBb. It bound to cell-bound C3b and stabilized C3bBb at 30 degrees in the presence of EDTA-GVB. The plasma protein H reduced the stabilization effect of the stabilized C3 convertase. These results suggest that binding of antibody to C3d may stabilize C3bBb. It seems likely that such antibody induces in C3b conformational change, which increases the C3bBb complex stability.

[Silent myocardial ischemia evaluated by ambulatory left ventricular function monitoring]

To determine whether left ventricular function is less disturbed in asymptomatic ischemia than in symptomatic ischemia, exercise-induced left ventricular function was measured in beat-to-beat using an ambulatory left ventricular function monitoring system. The study subjects were 22 patients with coronary artery disease. Supine and sitting ergometer exercise tests were performed. Of 44 exercise tests, 33 showed significant ST depression on electrocardiograms. Among these 33, 17 were asymptomatic: 16, symptomatic. The left ventricular functions during exercise of these 33 were analyzed and compared with those of five normal controls. The changes in end-diastolic volume were not so significant either in controls or in the asymptomatic and symptomatic groups, but the changes in end-systolic volume were reversed in the diseased groups, particularly in the symptomatic group. The changes in ejection fraction (EF), therefore, were significantly negative in the diseased group, particularly in the symptomatic group. The correlation between exercise-induced left ventricular dysfunction and symptoms was evaluated among the 33 patients. Symptoms were present in 35% (6/17) in less than 10% decrease in EF, 44% (4/9) in 10-15% decrease, and 85% (6/7) in greater than or equal to 15% decrease, respectively. Thus, asymptomatic ischemia represents a lesser degree of myocardial ischemia as indicated by mild left ventricular dysfunction, compared with symptomatic ischemia. However, some cases of severe myocardial ischemia did not develop symptoms. We concluded that silent myocardial ischemia is responsible for a lesser degree of myocardial ischemia and decreased pain perception.

Metastatic small cell carcinoma to the pineal body: case report

A case of metastatic small cell carcinoma to the pineal body is reported and the clinical and radiological features of this rare tumor are discussed. A 66-year-old man presented with progressive dementia, gait disturbance, vertical gaze palsy, and convergence retraction nystagmus. Computed tomographic scan revealed a 2 X 3-cm high-density mass in the pineal region, which showed strong contrast enhancement. The tumor was resected through a right occipital transtentorial approach. The pathological diagnosis of the surgical specimens was small cell carcinoma. A systemic workup for the primary lesion subsequently revealed small cell carcinoma of the lung. Although occurring rarely, metastatic tumor should be considered in the differential diagnosis of pineal tumor in elderly patients.

[Significance of "overshoot" elevation of ejection fraction in early recovery period after exercise in patients with coronary artery disease]

To investigate the relationship between "overshoot" elevation of left ventricular (LV) ejection fraction (EF) in the early recovery period after exercise and myocardial ischemia, LV function was measured in 5 healthy volunteers and 47 pts with coronary artery disease (CAD) using supine ergometer. EF at rest (EFRE), at peak exercise (EFEX), at peak of overshoot (EFOS) and time from cessation of exercise to peak of overshoot (T-OS) were measured using an ambulatory LV function monitor system with a high sensitive CdTe detector. The patients were classified into 3 groups according to EF depression (EFRE-EFEX) by exercise, i.e., D1 (EF decreases less than 5%): 15 pts, D2 (EF decreases 5-10%): 12 pts, D3 (EF decreases greater than or equal to 10%): 20 pts. Degree of overshoot which shows difference in EF between rest and peak of overshoot was 23.8 +/- 2.13% (mean +/- SD) in the normal group, 11.72 +/- 5.12% in D1, 9.56 +/- 6.51 in D2 and 6.12 +/- 4.15% in D3, respectively. T-OS was 1.4 +/- 0.48 in the normal group, 2.8 +/- 0.54 in D1, 4.5 +/- 2.36 in D2 and 5.6 +/- 1.93 min in D3, respectively. We conclude that left ventricular dysfunction was proportionally related to time-lapse from cessation of exercise to peak of overshoot while inversely related to degree of overshoot.

An outbreak of gastroenteritis associated with acute rotaviral infection in schoolchildren

In April 1988 a large outbreak of group C rotavirus infection associated with acute gastroenteritis occurred among schoolchildren and their teachers simultaneously at seven elementary schools in Fukui city, Japan. Of 3,102, 675 (21.8%) became ill. Clinical symptoms were mild, predominantly abdominal pain and vomiting, with diarrhea reported in only 27.6%. The outbreak subsided within 2 d. No pathogenic bacteria were found in fecal specimens; the virus particles detected by electron microscopy were morphologically indistinguishable from conventional infantile rotavirus. Immune electron microscopy showed that these virions formed large aggregates with convalescent serum and with the reference serum specific to group C rotavirus. Polyacrylamide gel electrophoresis showed similar RNA patterns for virus from this outbreak and typical group C rotavirus.

Treatment of secondary hyperparathyroidism in patients on maintenance hemodialysis

The effects of CaCO3 were investigated in 7 patients undergoing maintenance hemodialysis who had been treated with 1 microgram/day 1 alpha (OH)D3 and 2 g/day Al(OH)3. CaCO3 (3 g/day) was administered instead of Al(OH)3. The levels of serum total calcium and ionized calcium were significantly increased, the level of C-terminal parathyroid hormone was appreciably decreased and the levels of serum aluminum in all patients were reduced. There were no significant changes in the levels of serum phosphate, calcium x phosphate product, alkaline phosphatase, calcitonin, magnesium and bicarbonate. It is concluded that 3 g/day CaCO3 is equivalent to 2 g/day Al(OH)3 in terms of its phosphate-binding effect, and the prescription of CaCO3 together with 1 alpha (OH)D3 ameliorates secondary hyperparathyroidism.

[Changes in complement breakdown products and terminal complement complex in patients with acute glomerulonephritis]

In this study we examined the role of the complement system in acute glomerulonephritis (AGN). Breakdown products of complements (iC3b, C4d and Bb) and Terminal complement complex (TCC, SC5b-9 complex) in plasma samples were measured by ELISA. The microassay plates were coated with monoclonal antibodies which bind specifically to human iC3b, C4d, Bb and SC5b-9 complex. This assay accurately quantitates small amounts of in vivo complement activation. The plasma samples were drawn from patients with AGN and other glomerulonephritis. There were some patients with various glomerulonephritis whose plasma iC3b, C4d and Bb concentrations were higher than those in normal human. However specificity was not found. The ratios iC3b/C3 and C4d/C4 were increased in the early stages of AGN, but plasma Bb concentrations revealed no significant changes. Plasma SC5b-9 complex concentrations were increased in the early stages of AGN. C3c, C3d, C4d and SC5b-9 were found to be localised in the glomeruli of those AGN patients. It is suggestive that in these cases of AGN (especially case 2) complement activation is predominantly mediated through the classical pathway and TCC is formed by this activation. This complement activation in the blood and the renal tissue is presumed to be involved in the initiation and progression of AGN.

Effects of Ca2+ and Zn2+ on trifluoperazine-S100 proteins interactions: induced circular dichroism and fluorescence spectra

Interactions of trifluoperazine (TFP) with S100 proteins, EF-hand type Ca2+-binding proteins, in the presence of Ca2+ and Zn2+ were studied with induced circular dichroism (CD) and fluorescence spectra. The positive CD bands of TFP were induced at around 265 nm by adding either S100a or S100a0 protein in the presence of Ca2+. No CD band of TFP was, however, induced by adding S100b protein in the presence of Ca2+. Addition of Zn2+ to the TFP/S100 protein solutions did not induce any CD band at all. The fluorescence intensity of 2-p-toluidinylnaphthalene 6-sulfonate (TNS) bound to S100a or S100a0 protein decreased by adding TFP in the presence of Ca2+, while that bound to S100b protein decreased by adding TFP in the presence of Zn2+, indicating that TFP binds to S100a protein and S100a0 protein in a Ca2+-dependent manner and to S100b protein in a Zn2+-dependent manner. From these results together with other experimental findings it was suggested that (1) TFP binds to S100a protein and S100a0 protein in the presence of Ca2+, with half-saturation points of 18 and 3 microM, respectively, (2) TFP binds to S100b protein only in the presence of Zn2+, (3) alpha-subunit of S100 protein binds to TFP specifically in a Ca2+-dependent manner and beta-subunit in a Zn2+-dependent manner.

Site-directed mutageneses of rat liver cytochrome P-450d: catalytic activities toward benzphetamine and 7-ethoxycoumarin

Catalytic activities toward benzphetamine and 7-ethoxycoumarin of 11 distal mutants, 9 proximal mutants, and 3 aromatic mutants of rat liver cytochrome P-450d were studied. A distal mutant Thr319Ala was not catalytically active toward benzphetamine, while this mutant retained activity toward 7-ethoxycoumarin. Distal mutants Gly316Glu, Thr319Ala, and Thr322Ala displayed higher activities (kcat/Km) toward 7-ethoxycoumarin that were 2.4-4.7-fold higher than that of the wild-type enzyme. Although kcat/Km values of four multiple distal mutants toward benzphetamine were less than half that of the wild type, activities of these mutants toward 7-ethoxycoumarin were almost the same as or higher than the wild-type activity toward this substrate. The distal double mutant Glu318Asp, Phe325Tyr showed 6-fold higher activity than the wild-type P-450d toward 7-ethoxycoumarin. Activities of the proximal mutants Lys453Glu and Arg455Gly toward both substrates were much lower (less than one-seventh) than the corresponding wild-type activities. Catalytic activities of three aromatic mutants, Phe425Leu, Pro427Leu, and Phe430Leu, toward benzphetamine were less than 7% of that of the wild type, while the activities of these aromatic mutants toward 7-ethoxycoumarin were more than 2.5 times higher than the wild-type activity toward this substrate. From these findings, in conjunction with a molecular model for P-450d, we suggest that (1) the relative importance to catalysis of various distal helix amino acids differs depending on the substrate and that these differences are associated with the size, shape, and flexibility of the substrate and (2) the proximal residue Lys453 appears to play a critical role in the catalytic activity of P-450d, perhaps by participating in forming an intermolecular electron-transfer complex.

Influence of 1 alpha-hydroxy vitamin D3 (0.25 micrograms/day) and calcium carbonate on patients with chronic renal failure at the predialytic stage

The influence of a small amount of 1 alpha (OH)D3 on patients with chronic renal failure at the predialytic stage (CRFPS patients) receiving CaCO3 was investigated. 7 patients given CaCO3 (3 g/day) were administered 1 alpha (OH)D3 (0.25 micrograms/day) over a period of 12 weeks. 2 patients were eliminated from the study because of obvious deterioration of renal function. The others revealed no significant changes in levels of serum creatinine, adjusted calcium, phosphate, calcium x phosphate product, alkaline phosphatase, C-terminal parathyroid hormone, pH and bicarbonate. Our results indicated that even 0.25 micrograms/day 1 alpha (OH)D3 should not be prescribed to CRFPS patients given 3 g/day CaCO3. We recommend a little sole use of CaCO3 in CRFPS patients, paying attention to any exacerbation of renal function due to a rise in serum calcium concentration, when therapy for secondary hyperparathyroidism is required.

Mutations at the distal and proximal sites of cytochrome P-450d changed regio-specificity of acetanilide hydroxylations

Regio-specificities of acetanilide hydroxylations were studied for 11 distal, 9 proximal and 3 aromatic mutants of cytochrome P-450d. Ratios of turnover numbers among these products were remarkably changed depending on the mutants. For example, the ratio of turnover number, para:ortho:meta = 7:0.1:0.3 for the wild type changed to 11:4:3 for a distal mutant, Thr322Ala, or to 13:13:1 for a proximal mutant, Arg455Gly. It was suggested that regio-specificities of microsomal P-450 enzymes are controlled cooperatively by the whole structure of the protein molecules which influences the tertiary structure of the distal environment.

Bindings of axial ligands to cytochrome P-450d mutants: a difference absorption spectral study

By site-directed mutagenesis, we made several cytochrome P-450d (P-450d) mutants as follows: Asn310Phe (D13), Ile312Leu (D14), Glu318Asp (D15), Val320Ile (D16), Phe325Thr (D19), Asn310Phe,Ile312Leu (M6), Glu318Asp,Val320Ile (M7), Phe325Thr, Glu318Asp (M3). This region (Asn-310-Phe-325) is supposed to be located in the distal helix above the heme plane in P-450d, being conjectured from the structure of P-450cam. We studied Soret spectral changes of those mutants by adding several axial ligands such as aniline, pyridine, metyrapone, 2-phenylimidazole and 4-phenylimidazole. Binding constants (Kb) of aniline and pyridine to the single and double mutants were higher than those to the wild type by 2-10-times. The double mutations did not additively increase the Kb values compared with those to the single mutants. In contrast, Kb value (1.0.10(5) M-1) of metyrapone to the double mutant M3 was much higher than that (2.0.10(3) M-1) of the wild type and those of the single mutants, D15 (4.5.10(4) M-1) and D19 (1.6.10(4) M-1). The increased affinity of metyrapone to the mutant M3 may be attributed to an interaction of the hydrophobic group of metyrapone with nearby hydrophobic group(s) produced cooperatively by the double mutation of P-450d. Kb values of 2-phenylimidazole and 4-phenylimidazole to the mutant M3 were also the highest among those of the mutants and the wild type. Therefore, it was suggested that this region (from Asn-310 to Phe-325) must be located at the distal region of the heme moiety and form, at least, a substrate-binding region of membrane-bound P-450d.

Solvent effect on MCD of Fe(III) heme complexes: magnetic circular dichroism spectra of five-coordinated high-spin iron(III) protoporphyrin-IX-dimethylester in the visible region and their environmental effect. A characterization of the visible electronic transitions in Fe(III) high-spin porphyrins

Magnetic circular dichroism (MCD) spectra were observed to characterize the nature of the visible bands for high-spin Fe(III) protoheme derivatives with p-nitrothiophenolate, p-nitrophenolate, and methoxy anion as the fifth ligands in several solvents. The visible MCD bands for p-nitrophenolate heme were very sensitive to the solvent polarity, but that those for p-nitrothiophenolate heme and methoxy heme were not dependent on solvent polarity. Thus, both the two visible MCD band positions and the magnitudes were dependent on ET value (a solvent polarity parameter) in the former complex, but not in the latter two complexes. The results are consistent with previously proposed electronic structures of high-spin Fe(III) heme complexes.

C3 nephritic factor and C4 nephritic factor in the serum of two patients with hypocomplementaemic membranoproliferative glomerulonephritis

Both C3 nephritic factor (C3NeF) and C4 nephritic factor (C4NeF) were found in the serum of two patients with hypocomplementaemic membranoproliferative glomerulonephritis type 1 (H-MPGN type 1). Both stabilizing activities were associated with the IgG fraction. The serum levels of C3 and C5 were quite low, whereas the levels of early components and control proteins were in the normal range.

Immuno-affinity purification of specific antibodies against vasoactive intestinal polypeptide (VIP) on VIP (1-10)-linked polydimethylacrylamide resin

A novel method for immuno-affinity purification of specific antibodies against amino-terminal (N-terminal) porcine vasoactive intestinal polypeptide (p-VIP) was developed. The antiserum VP (No. 6203) elicited by p-VIP-immunoglobulin G (IgG) conjugate was heterogenous and reacted not only with the N-terminal fragments of p-VIP but also with carboxy-terminal (C-terminal) fragments. To obtain specific antibodies against the N-terminal fragment of p-VIP, antiserum VP was purified by column chromatography on N-terminal decapeptide (p-VIP 1-10)-linked polydimethylacrylamide resin. The antibody thus obtained was highly specific to the N-terminal sequence of p-VIP and hardly reacted with the C-terminal fragments of VIP in enzyme-linked immunosorbent assay.

Role of the calcium-calmodulin system in the adenylate cyclase activity of vascular smooth muscle

In order to evaluate the relationship between the calcium-calmodulin system and the adenylate cyclase activity of vascular smooth muscle, we examined the effects of several calcium effectors on the basal and stimulated adenylate cyclase activity. Thoracic aortae were removed from Wistar rats and the tissues were homogenated with cold homogenizing buffer containing 1 nM EDTA. Membrane protein fraction of the smooth muscle was prepared by centrifugation at 37,000 g. In this procedure, endogenous guanine nucleotides and contractile proteins remained. The protein fraction was incubated with 2 mM EGTA, 50 microM trifluoperazine, 0.1 microM A23187 or 25 microM calmodulin under basal and stimulated (50 microM isoproterenol, 100 microM GTP and 50 microM forskolin) conditions. The adenylate cyclase activity was determined by a method modified in our laboratory using double isotope counting. Trifluoperazine reduced the basal adenylate cyclase activity significantly (p less than 0.01) as well as the stimulated enzyme activities. A23187 did not affect the basal enzyme activity, but elevated the isoproterenol stimulated enzyme activity significantly (p less than 0.05). EGTA did not affect the basal and stimulated adenylate cyclase activities. Calmodulin elevated the basal enzyme activity significantly (p less than 0.02), but did not affect the stimulated enzyme activities. These results suggest that the calcium-calmodulin system is necessary for maintenance of the adenylate cyclase activity of vascular smooth muscle cells. The calmodulin acting site is considered to be the catalytic subunit, and stimulation of the enzyme is accelerated by calcium ion.

Epstein-Barr virus with transforming and early antigen-inducing ability originating from nasopharyngeal carcinoma: mapping of the viral genome

Epstein-Barr virus (EBV) from a human hybrid epithelial cell line (NPC-KT), derived from the fusion of human adenoidal cells and EBV genome-containing primary nasopharyngeal carcinoma cells (NPC) has both transforming and early antigen (EA)-inducing abilities. EBV DNA from NPC-KT cells was partially digested with TaqI and ligated to the cloning vector pJB8 at the ClaI site. This cosmid library encompassed the whole genomic DNA of the virus except for several kb of the terminal fragments. The identification and location of each of the cloned DNA fragments have been defined by hybridization to blots prepared with B95-8 and NPC-KT virion DNA. Defective heterogeneous restriction enzyme fragments of the viral DNA were not identified in any of the cosmid clones nor detected in hybridizations to virion DNA, which indicates that a single virus population derived from the NPC tissue has both transforming and EA-inducing activities.

[Limitation of myocardial infarct size by polyethylene glycol-conjugated superoxide dismutase in a canine model of 90 min coronary occlusion followed by 4 days of reperfusion]

The role of oxygen free radicals in the genesis of myocardial reperfusion injury is supported by the studies with superoxide dismutase (SOD) which provides protection against the extention of myocardial injury. However, the efficacy of SOD may be of limited value due to its short plasma half-life of 5-6 min. Conjugation of SOD to polyethylene glycol (PEG-SOD) increases the half-life to greater than 30 hours. Forty-two male, mongrel anesthetized dogs were subjected to occlusion of left circumflex coronary artery for 90 min followed by 4 days of reperfusion. Dogs were randomized to receive either PEG-SOD (1,000 U/kg) or PEG-Albumin via left atrium, starting 15 min before reperfusion and ending simultaneously with reperfusion, and were sacrificed 4 days later. The hearts were stained by ex vivo dual perfusion technique for the determination of myocardial infarct size. Infarct size expressed as a percent of area-at-risk in PEG-SOD (n = 13) and PEG-Albumin (n = 13) treated dogs differed significantly between groups: 29.2 +/- 1.6% vs 44.2 +/- 2.6%, respectively (p less than 0.01) with no observed difference in the size of area-at-risk: 46.0 +/- 1.6% vs 44.4 +/- 1.4% (n.s.). Hemodynamic parameters between groups did not differ during coronary artery occlusion and could not account for the effect of PEG-SOD on infarct size. Collateral blood flows to the inner 2/3 of the ischemic myocardium for both groups did not differ. Plasma SOD activity in PEG-SOD group initially exceeded 20 U/kg and sustained significantly for 4 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Production of interleukin 1 in glomerular cell cultures from rats with nephrotoxic serum nephritis

To investigate the role of cytokines in the pathogenesis of experimental glomerulonephritis (GN), we examined interleukin 1 (IL-1) activity in isolated glomeruli of rats with an accelerated autologous form of nephrotoxic serum nephritis (NTSN). Glomeruli were isolated and explanted in tissue culture. The prominent feature of the glomerular outgrowth of the glomeruli in the NTSN was the presence of large numbers of type III cells (macrophages). In addition, there were significantly greater numbers of type II (mesangial) cells in culture from the NTSN rats as compared with glomeruli from normal rats, though the numbers of type I (epithelial) cells were the same. IL-1 bioactivity was significantly higher in culture supernatants generated by glomeruli isolated from NTSN animals versus normal animals early in the course of the disease. When glomerular culture supernatants and purified IL-1 were pre-incubated with an anti-IL-1 beta antibody, a parallel decrease of the biological activity was found, suggesting that the biologically active binding sites of the culture supernatants and monocyte-produced IL-1 share some common structure. The administration of a rabbit anti-rat macrophage serum (AMS) prevented the outgrowths of type III cells (macrophages) and type II (mesangial) cells and reduced the production of IL-1 activity in the NTSN rats. In this experimental model IL-1 synthesis, probably by multiple cell types, is present early in the disease process and perhaps may be an important mediator of glomerular immune injury.

Specific inhibition of class II MHC gene expression by anti-sense RNA

We have established an anti-sense RNA system which is capable of regulating expression of the class II (Ia) molecule coded for by the major histocompatibility complex in cultured mouse cells. Various areas of the I-A beta chain gene were subcloned in an anti-sense orientation to the 3' of the dihydrofolate reductase (DHFR) cDNA under the control of the human metallothionein IIa gene promoter. These anti-sense DNA constructs were transfected into M12.4 cells, a BALB/c B lymphoma cell line which expresses both I-A and I-E molecules on the cell surface. I-A expression of selected clones transfected with anti-sense DNA encompassing the 5' untranslated region (UT) (100 or 310 bp) including the translation start site or the poly(A) addition signalling sequence in the 3' UT (250 bp) of the I-A beta chain gene were specifically reduced to less than 5% of the control M12.4 cell surface I-A expression. These clones had normal levels of I-E expression. However, transfection of the anti-sense DNA to the beta 1 domain (510 bp) including the splicing donor and acceptor sequences did not affect the expression of I-A molecules. The same antisense DNA constructs (100 bp of the 5' UT or 250 bp of the 3' UT) without the DHFR cDNA (710 bp) did not down-regulate the expression of I-A molecules, indicating that either the physical length of the anti-sense RNA or specific DHFR cDNA sequences are also important.(ABSTRACT TRUNCATED AT 250 WORDS)

[A case of sarcoidosis associated with membranous nephropathy]

A 59-year-old woman was admitted to the hospital with a complaint of right visual disturbance. At admission, she had proteinuria and microscopic hematuria. The pulmonary X-ray showed bilateral hilar lymphadenopathy (BHL) but tuberculin test were negative. Also, bronchoalveolar lavage (BAL) and renal biopsy were performed. Bronchoalveolar lavage fluid (BALF) contained a high percentage of OKT 4 positive cells. In renal biopsy, light microscopic study showed thickening glomerular basement membrane (GBM) with tubulo-interstitial legion. Immuno-fluorescent study revealed granular deposits of IgG along glomerular capillary wall. Electron microscopic study showed subepithelial electron dense deposits of GBM, which are characteristic for membranous nephropathy (MN). It is well known that both sarcoidosis and MN are associated with immunological abnormality. This case might be significant for the study of pathogenesis of sarcoidosis.

Effect of antimacrophage serum on the proliferation of glomerular cells in nephrotoxic serum nephritis in the rat

To evaluate the effect of a rabbit anti-rat macrophage serum (AMS) on glomerular cells in vivo, glomeruli were isolated from an accelerated autologous form of nephrotoxic serum nephritis (NTSN) in rats and grown in tissue culture. The prominent feature of the glomerular outgrowth of the glomeruli in the NTSN was the presence of large numbers of type III (macrophages) cells, which were not present in cultured normal glomeruli. In addition, there were significantly greater numbers of type II (mesangial) cells in culture from the NTSN rats as compared with glomeruli from normal rats though the numbers of type I (epithelial) cells were the same. The administration of AMS prevented the outgrowth of macrophages and reduced the number of mesangial cells in the outgrowth of glomeruli from the NTSN rats. The AMS-treated rats showed profound reduction in proteinuria. Light micrographs showed only minor histologic lesion in the AMS-treated rats. These findings suggest that AMS may be applicable to the modulation of the proliferative response seen in NTSN.

[Activation of complement by hemodialysis membrane]

Incubation of normal human serum with hemodialysis membranes in vitro resulted in conversion of C3 which was detected by crossed immunoelectrophoresis. In addition, formation of C3d was also observed, as was detected by double-decker rocket immunoelectrophoresis. Furthermore, breakdown products of complement (iC3b, C4d & Bb) in plasma samples were measured by ELISA. The microassay plates were coated with monoclonal antibodies which bind specifically to human iC3b, C4d and Bb, respectively, while the plasma samples were drawn from five polycystic kidney patients during initial hemodialysis. As a result, the iC3b and Bb levels in plasma were seen to increase during hemodialysis but the C4d levels revealed no significant changes. It was also observed that the Bb levels in patients undergoing hemodialysis were significantly higher than those in various renal and collagen diseases. Terminal complement complex (TCC) was not present in detectable amounts in normal human serum when measured by ELISA. However, incubation of normal human serum with hemodialysis membranes in vitro resulted in detection of TCC. TCC was present in the same plasma samples drawned from the five polycystic kidney patients during initial hemodialysis. It is suggestive that activation of complement by hemodialysis membrane is predominantly mediated through the alternative pathway and products such as TCC and anaphylatoxin are formed by this activation.

Diminished sympathetic excitation of locus coeruleus noradrenergic neurons in the conscious mature spontaneously hypertensive rat

We undertook a study to determine whether the activation of the nucleus locus coeruleus might be responsible for the sympathetic hyperactivity in the spontaneously hypertensive rat (SHR). Conscious mature SHR showed increased arterial pressure and plasma catecholamines with electrical stimulation of the locus coeruleus. However, SHR showed smaller increases in arterial pressure and plasma noradrenaline than Wistar-Kyoto rats (WKY). The spontaneous unit discharge in locus coeruleus neurons responded reciprocally to peripherally induced changes in arterial pressure and blood volume. However, the unit discharge in the SHR locus coeruleus is less responsive than that in WKY. Therefore, the locus coeruleus in mature SHR does not seem to be involved in the hyperactivity of the sympathetic nervous system. However, this may not be the case in young SHR.

Effect of elastase on blood pressure and urinary excretions of prostaglandins and catecholamines in the spontaneously hypertensive rat (SHR)

The effects of elastase on blood pressure (B.P.) and the urinary excretions of prostaglandins (PGs) and catecholamines in the spontaneously hypertensive rat (SHR) were investigated. Male SHRs (n = 20), castrated at 4 weeks of age, were divided into 2 groups. Elastase was then dissolved in saline (5 mg/ml) and injected subcutaneously (10 mg/kg of body weight) into the SHRs of one of the 2 groups (n = 10) at 5 to 13 weeks of age, and the same dose of saline only was injected subcutaneously into the SHRs of the other group (n = 10) as a control during the same period. B.P. was measured by the tail-cuff method every 2 weeks. Urine sampling and measurement of body weight (B.Wt.) were also performed every 2 weeks. The B.P. in the elastase-administered group (184.1 +/- 3.3 mmHg) was found to be significantly lower (p less than 0.02) than that of the control group (198.0. +/- 4.3) at 9 weeks of age. A significant difference (p less than 0.01) in B.P. between the control group (204.0 +/- 4.5) and the elastase-administered group (187.3 +/- 2.7) was also observed at 13 weeks of age. The urinary excretion of 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) in the control group (5.1 +/- 0.4 ng/day/100 g B.Wt.) at 11 weeks of age was significantly lower (p less than 0.05) than that of the elastase-administered group (10.4 +/- 1.3).(ABSTRACT TRUNCATED AT 250 WORDS)

Sequence of mechanical and electrical changes during myocardial ischemia: assessment by an ambulatory left ventricular function monitor

To investigate the relationship between left ventricular function and electrical changes during myocardial ischemia, ambulatory left ventricular function monitoring and ECG recording were made during the ergometer exercise test in 14 patients with coronary artery disease. An ambulatory ventricular function monitor consists of a small cadmium telluride (CdTe) radionuclide probe (250 g) affixed to the patient's chest wall, a preamplifer (10 g), and a portable data acquisition unit (600 g). Left ventricular time-activity curves were recorded continuously using this monitor, and the end-systolic count (volume), end-diastolic count (volume) and ejection fraction were calculated after background subtraction. Twenty-eight exercise tests were performed in the supine and upright positions. In 15 tests, left ventricular dysfunction, i.e., an increase in the end-systolic count (greater than or equal to 10%) and a decrease in ejection fraction (greater than or equal to 5%), and ST depression (greater than or equal to 0.1 mV) were observed. In these 15 tests, exercise duration was 362 +/- 27 sec. Left ventricular dysfunction occurred earlier than ST depression and the time difference was 97 +/- 19 sec. Left ventricular function recovered 33 +/- 8.5 sec after discontinuation of exercise, while ST depression continued for the additional 85 +/- 18.5 sec after recovery of left ventricular function. In conclusion, 1) left ventricular dysfunction occurs earlier than electrical changes during exercise-induced ischemia; 2) left ventricular dysfunction improves earlier than electrical changes after exercise; and 3) the same temporal sequence exists in the restoration from myocardial ischemia.

Effects of low magnesium diet on the vascular prostaglandin and fatty acid metabolism in rats

Deficiency of magnesium with cardiovascular effects is thought to be related to alterations in the biosynthesis of prostaglandins (PGs) in the vasculature. Measurements were made of the PGE2, 6-keto-PGF1 alpha and thromboxane B2 (TxB2) outflow from the perfused isolated mesenteric arterial bed and the fatty acid composition of the tissue in rats maintained for 14 weeks on a low magnesium (LMg) diet. The serum Mg levels were significantly decreased and the serum Ca levels were significantly increased in the LMg group as compared to the controls. The arachidonic acid concentration in the triacylglyceride fraction was significantly increased in the LMg group. Long chain polyunsaturates such as 22:4n6 and 22:6n3 were consistently increased in the LMg rats as compared to the controls in both the phospholipid and triglyceride fractions as previously reported in other tissues. The PGE2, 6-keto-PGF1 alpha and TxB2 outflows were significantly increased in the LMg group as compared to the controls. These findings suggest that the biosynthesis of eicosanoids, mainly PGI2, is stimulated in Mg deficiency, and this may provide protection against intracellular Mg depletion and Ca accumulation, so as to counteract to the constricted and hyperreactive state of the vasculature in such a condition.

Effect of prolonged ACTH stimulation on adrenal renin and aldosterone

Changes in adrenal renin, which have been regarded as mediator of aldosterone secretion in the adrenal gland, following prolonged ACTH treatment were investigated in male Wistar rats. After 2 days of daily sc injection of ACTH (Cortrosyn-Zinc, 50 micrograms/day), parallel increases in adrenal renin and aldosterone, and plasma aldosterone (PA) were induced. The plasma renin activity (PRA) was slightly but not significantly decreased. Prolonged treatment with ACTH for 8 days increased the adrenal renin, causing a marked reduction in the adrenal aldosterone concentration. The degree of decrease in the PRA was again not significant and similar to that after 2 days of ACTH treatment. Contrary to previout reports which have indicated participation of adrenal renin in the regulation of aldosterone secretion in the adrenal gland, the present results showed reciprocal changes in adrenal renin and aldosterone after prolonged treatment with ACTH. The present findings suggest a complicated relation between adrenal renin and aldosterone secretion in the adrenal gland.

Isolation of apolipoproteins from carotenoid-carrying lipoprotein in the serum of chum salmon, Oncorhynchus keta

Carotenoid-carrying lipoprotein (CCL) was rapidly isolated from the high density lipoprotein (HDL) fraction of the upstream migrating male chum salmon (Oncorhynchus keta) by a single-step density gradient ultracentrifugation. The two apolipoproteins (Mr = 24,000 and 12,000; designated apo-I and apo-II, respectively) were readily dissociated and separated in 0.1% SDS by gel filtration chromatography. Prominent features of the amino acid composition in the CCL included the relative high levels of glutamic acid, alanine, leucine, and lysine, and the low cysteine content. Apo-I, as well as the CCL, was rich in glutamic acid, alanine, leucine, and lysine. Compared to the amino acid composition of apo-I, apo-II included relatively high levels of glycine and tyrosine, and low threonine, serine, and arginine contents. When the intact CCL particle was treated with trypsin, apo-I was rapidly proteolyzed, while apo-II was resistant. However, both apo-I and apo-II isolated from the CCL particle were readily digested with trypsin. This suggested that a different structural arrangement rather than the amino acid compositions of the apolipoproteins was associated with the limited trypsin digestion of the CCL particle. Apo-II may be sheltered from the aqueous environment and lie partly within the CCL particle. The properties of both the HDL fraction and apolipoproteins from pink salmon (Oncorhynchus gorbuscha) were similar to those of the CCL from chum salmon.