Ca(2+)-activated outward-rectifier K+ channels and histamine release by rat gastric enterochromaffin-like cells

Gastric enterochromaffin-like (ECL) cells were isolated from rat gastric fundic mucosa by Percoll density-gradient centrifugation and counter-flow elutriation. About 67% of cells in the purified cell suspension were ECL cells, which were reacted with anti-histidine decarboxylase antibody. A23187, a calcium ionophore, at 0.1-10 microM induced histamine release from ECL cell-rich suspension, indicating that the Ca2+ pathway is involved in the mechanism of histamine release from the ECL cells. A23187 at 5 microM significantly increased outward-rectifier cationic current in 62% of cells in the ECL cell-rich factions. A23187-sensitive cells showed acridine orange uptake. In single-channel recordings, a Ca(2+)-dependent outward-rectifier K+ channel of large conductance (146 +/- 22 picosiemens) was found in the cell that showed acridine orange uptake. The channel opened in a voltage-dependent manner at 0.1 microM of intracellular free Ca2+ concentration. These results may suggest that opening of the Ca(2+)-activated K+ channel is one of the steps involved in the mechanism of histamine release in ECL cells.

[Perioperative management of dialysed patients for orthopedic surgery]

Recently, renal osteodystrophy is a remarkable problem in patients on long-term hemodialysis (HD). In this retrospective study, we evaluated the perioperative management of 21 patients receiving orthopedic surgery between January 1990 and December 1992. These patients had been maintained on HD for an average of 8.6 years (range, 18 months-20 years). The primary causes of orthopedic surgery were amyloidosis, diabetic gangrene, rheumatoid arthritis and fractures. Laminectomy, replacement of arthropathy, osteosynthesis and amputation of the lower extremity were undertaken. General anesthesia was performed on six patients. Vecuronium was given to all of these patients. Isoflurane was used in 5 patients and sevoflurane in 1 patient. Regional anesthesia was used in 15 patients. During anesthesia, the average infusion rate of intravenous fluids was 2.7 ml.kg-1.h-1, and the intraoperative complications included hypertension in 16, hypotension in 12, arrhythmia in 4 and prolonged sedation in 2 patients. Postoperative complications included hyperkalemia in 2, pneumonia in 2, psychological disorder in 3, clotting fistula in 1 and delayed wound healing in 7 patients. One early death in a diabetic patient following amputation occurred on the 13th postoperative day. Preoperative HD was performed within 24 hours and postoperative HD within 72 hours of the operation. Nafamostat mesilate was used as an anticoagulant. Excessive removal of potassium must be avoided during preoperative HD to prevent arrhythmia. The well-managed elective patients gave a good result. However, extreme care in nutrition and infection control should be taken, especially in diabetic patients.

Protective effect of DS-4574, a peptidoleukotriene receptor antagonist, against endotoxin-induced intestinal injury in rats

We evaluated the protective effect of DS-4574 (6-(2-cyclohexylethyl)-[1,3,4]thiadiazolo[3,2-a]-1,2,3- triazolo[4,5-d]pyrimidin-9(3H)-one), a peptidoleukotriene receptor antagonist, against intestinal mucosal injury evoked by endotoxin in rats by exploring changes in hematocrit and plasma leakage along with morphological features. Treatment with Escherichia coli endotoxin (5 mg/kg i.v.) alone elicited hemoconcentration, vasocongestion and a marked mucosal necrosis. DS-4574 (10-50 mg/kg) effectively prevented these changes on either oral or intraduodenal administration. These results demonstrate that peptidoleukotrienes may be key mediators in the intestinal injury induced by endotoxin in rats.

[Effects of 2-(3,4-dimethoxyphenyl)ethylamine derivative (ecabapide, DQ-2511) and its metabolites on water-immersion restraint stress-induced gastric ulcers in rats]

Ecabapide (DQ-2511) has been demonstrated to be effective in preventing water-immersion restraint stress ulceration of rats. In the present study, we aimed to define the active molecular features of ecabapide. Seven of 9 degraded materials identified as ecabapide metabolites were synthesized and their antiulcer activities were compared with that of the parent compound. Ecabapide was potent to prevent gastric ulcer formation at the doses of 30-300 mg/kg i.p. Three metabolites (V, VIII and IX) were also active to inhibit ulceration induced by the stress. The antiulcer activity of IX was similar to that of ecabapide, whereas V and VIII had less activities. After the oral administration of ecabapide, the plasma levels of IX reached to less than 15% of that of ecabapide and also IX was largely excreted into the feces. Therefore, the potential implication of the metabolite (IX) as the active component in the antiulcer effect of ecabapide could be excluded. Furthermore, it is also unlikely that the high polar metabolites (IV and VII) are implicated in significant contribution for antiulcer action. In conclusion, we have shown that ecabapide prevents water-immersion restraint stress-induced gastric ulcers, and that this activity is probably mediated by the action of the parent compound.

Ebselen, a seleno-organic compound, protects against ethanol-induced murine gastric mucosal injury in both in vivo and in vitro systems

The inhibitory effect of the seleno-organic compound ebselen on ethanol-induced murine gastric mucosal injury was examined. In an in vivo study, absolute ethanol (50 microliters/mouse, oral) produced marked gastric mucosal necrosis along with hemorrhage or edema and elevations in both lipid peroxide and peptidoleukotriene levels in the fundic mucosa. Pretreatment with ebselen (30 and 100 mg/kg, oral) significantly prevented this gastric mucosal injury and, further, remarkably decreased the elevated lipid peroxide and peptidoleukotriene levels. In an in vitro study using a murine gastric surface mucous cell line GSM06, exposure to ethanol concentration dependently elicited cell damage (7.5-17.5% ethanol) and an increase in lipid peroxides without alterations in peptidoleukotrienes (15% ethanol). Addition of ebselen (10 and 100 microM) to this system (15% ethanol) significantly inhibited the cell damage and completely prevented the increase in lipid peroxide level. These results indicate that ebselen protects against murine gastric mucosal injury both in vivo and in vitro, and that this protection may be related at least in part to its inhibitory action on lipid peroxides.

Variant type of teratoma appearing as a primary solid dermoid tumor in the rectum: report of a case

We report herein the rare case of a 39-year-old woman found to have a primary solid dermoid tumor in the rectum. The patient presented after noticing a small amount of anal bleeding, and physical examination revealed a walnut-sized hard tumor, palpable in the anterior rectum, located about 9 cm from the anal verge. Morphologic examinations revealed a polypoid lesion with some hair surrounded by rectal mucosa, and four biopsy specimens from the lesion showed normal squamous epithelium. The tumor, which measured 2.5 x 2.1 x 1.3 cm, was removed by endoscopic polypectomy. Microscopically, the tumor was diagnosed as a solid dermoid tumor without a cyst, a variant type of mature teratoma or dermoid cyst. Since 1914, only 12 such cases, including ours, have been reported in Japan. The clinical features and diagnostic and therapeutic methods applied thereto are discussed.

Inhibitory effect of DS-4574, a mast cell stabilizer with peptidoleukotriene receptor antagonism, on gastric acid secretion in rats

We examined the inhibitory effect of DS-4574 (6-(2-cyclohexylethyl)[1,3,4]thiadiazolo[3,2-alpha]-1,2,3- triazolo[4,5-d] pyrimidin-9(3H)-one), a mast cell stabilizer with peptidoleukotriene receptor antagonism, on gastric acid secretion stimulated by several secretagogues in rats. In anesthetized rats with acute gastric fistulas, DS-4574 (50 mg/kg, intraduodenal) significantly inhibited gastric acid secretion induced by both carbachol (50 micrograms/kg, s.c.) and pentagastrin (75 micrograms/kg, s.c.) but not by histamine (2.5 mg/kg, s.c.). In unanesthetized pylorus-ligated rats, DS-4574 (10 and 25 mg/kg, intraduodenal) markedly suppressed increases in gastric acid output and histamine leakage into the gastric juice produced by carbachol (0.1 mg/kg, s.c.) or pentagastrin (1 mg/kg, s.c.). When the relationship between acid output and histamine leakage elicited by carbachol and pentagastrin was assessed, there was a close correlation (r = 0.84) that was highly significant (P < 0.01). In the in vitro study with rat gastric tissues, DS-4574 (10(-7)-10(-5) M) had no effect on the K(+)-dependent ATPase activity or on aminopyrine uptake into mucosal preparations containing parietal cells stimulated by carbachol (10(-5) M), histamine (10(-4) M), or dibutyryl-cyclic AMP (10(-3) M). These results suggest that the effect of DS-4574 may be mediated by inhibition of endogenous histamine from histamine-storing cells in the stomach.

Inhibitory effect of DS-4574, a peptidoleukotriene antagonist with mast cell stabilizing action, on compound 48/80-induced gastric mucosal lesions in rats

We evaluated the inhibitory effect of DS-4574, a peptidoleukotriene antagonist with mast cell stabilizing action, on rat gastric mucosal lesions induced by compound 48/80 (C48/80: a mast cell degranulator), in comparison with those of disodium cromoglycate (DSCG: a mast cell stabilizer), LY171883 (a peptidoleukotriene antagonist) and cimetidine (a histamine H2 receptor antagonist). Subcutaneous administration of C48/80 (1 mg/kg) once daily for four consecutive days produced extensive gastric lesions in the fundic mucosa. DS-4574 (20, 50 and 100 mg/kg/day, oral) and DSCG (200 mg/kg/day, intraperitoneal) treatment markedly inhibited formation of these mucosal lesions, but LY171883 (100 and 200 mg/kg/day, oral) and cimetidine (400 mg/kg/day, oral) treatment did not. Moreover, DS-4574 and DSCG significantly suppressed both hyperhistaminemia and histamine release from rat peritoneal mast cells induced by C48/80. These results indicate that the inhibitory effect of DS-4574 on gastric lesions induced by C48/80 may be related to its mast cell stabilizing action, but to neither its antisecretory nor its peptidoleukotriene antagonistic activity.

Antisecretory effect of DS-4574, a mast cell stabilizer with peptidoleukotriene antagonism, on gastric acid secretion in the pig

The antisecretory effect of DS-4574, a mast cell stabilizer with peptidoleukotriene antagonism, on the hypersecretion of gastric acid stimulated by several secretagogues was examined in the pig. Goettingen miniature pigs with chronic gastric fistula were used. Intramuscular injection of carbachol (60 micrograms/kg), tetragastrin (50 micrograms/kg) or histamine (200 micrograms/kg)-induced gastric acid hypersecretion. Intraduodenal administration of DS-4574 (10 and 20 mg/kg) significantly inhibited both the hypersecretion induced by carbachol and that by tetragastrin. On the other hand, DS-4574 (50 mg/kg, intraduodenal) did not suppress histamine-induced hypersecretion. In the in vitro study, no effect on hog gastric K(+)-dependent ATPase activity was found at concentrations of DS-4574 from 10(-7) to 10(-4) M. These results were highly similar to those in the rat. The suppression of histamine release from histamine-containing cells in the gastric mucosa of the rat was concluded to be an antisecretory effect of DS-4574.

Mechanism of the inhibition of hog gastric H+,K(+)-ATPase by the seleno-organic compound ebselen

The effect of 2-phenyl-1,2-benzisoselenazol-3 (2H)-one (ebselen, CAS 60940-34-3), a seleno-organic compound, on the partial reaction steps of H+,K(+)-ATPase in hog leaky gastric vesicles was examined. Ebselen inhibited K(+)-dependent ATPase activity (IC50 = 0.06 mumol/l), phosphoenzyme formation (IC50 = 0.25 mumol/l), and K(+)-dependent p-nitrophenylphosphatase activity (IC50 = 0.09 mumol/l: dephosphorylation step of this enzyme). Furthermore, this compound prevented changes in the fluorescence intensity of flourescein isothiocyanate-labeled enzyme (E1-->E2K form, IC50 = 0.33 mumol/l). Pretreatment with 2 mmol/l of dithiothreitol (DTT) used as a sulfhydryl compound completely protected against these inhibitory effects. These findings indicate that ebselen-induced inactivation of gastric H+,K(+)-ATPase may result from prevention of the partial reaction steps, which include phosphorylation, dephosphorylation and conformational change (E1-->E2K form), through interference with sulfhydryl groups of the enzyme.

Establishment of gastric surface mucous cell lines from transgenic mice harboring temperature-sensitive simian virus 40 large T-antigen gene

We succeeded in establishing two gastric surface mucous cell lines (designated as GSM06 and GSM10), which produce periodic acid-Schiff (PAS)- and concanavalin A (Con A)-positive glycoproteins, from a primary culture of gastric fundic mucosal cells of adult transgenic mice harboring a temperature-sensitive simian virus 40 large T-antigen gene. At the permissive temperature (33 degrees C), GSM06 and GSM10 cells grew until confluent monolayers were formed and have now been in culture for more than 9 months with regular passaging. Con A-horseradish peroxidase- and PAS-positive staining indicated that these cells retain the characteristics of gastric surface mucous cells. GSM06 cells showed temperature-sensitive growth in culture and expressed SV40 large T-antigen at the permissive temperature but not at a nonpermissive temperature (39 degrees C). In contrast, GSM10 cells showed temperature-insensitive growth and expressed T-antigen at both permissive and nonpermissive temperatures. To our knowledge, this is the first report of the establishment of gastric surface mucous cell lines from animals. These immortalized cell lines with normal characteristics may serve as good experimental models for the basic and applied biology of gastric surface mucous cells.

Protective effect of DS-4574 on gastric mucosal injury induced by acidified ethanol in rats

We compared the protective effect of DS-4574, a peptidoleukotriene receptor antagonist with mast cell stabilizing action, on rat gastric mucosal injury induced by acidified ethanol to that of LY171883, a selective peptidoleukotriene receptor antagonist. Oral treatment with DS-4574 (1-10 mg/kg) or LY171883 (100 and 300 mg/kg) markedly suppressed this mucosal necrosis. Moreover, DS-4574 (10 mg/kg) significantly inhibited both mucosal edema and degranulation of mucosal mast cells. LY171883 (300 mg/kg) protected only from mucosal edema, but not degranulation of mucosal mast cells. These results suggest that DS-4574 possesses protective actions against gastric injury including the reduction of degranulation of mucosal mast cells, which are different from those of LY171883.

[Prophylactic effects of mitomycin C (MMC) on the liver recurrence in a rabbit gastric VX2 cancer model with high frequency of the recurrence]

Prophylactic effects of mitomycin C (MMC) injection protocol with different dose, periods and routes on liver recurrence were examined, using 53 gastric VX2 cancer rabbits. All the gastric cancer lesions without liver metastases were resected 14 days after implantation of VX2 cancer cells into the stomach, and all the animals were autopsied 14 days after resection. Multiple liver recurrence was found in 75% of MMC non-injection control 8 rabbits. The recurrence was not found in 10 animals with portal MMC 0.5 and 0.25mg/kg injection after resection, although 80% of 5 animals with the 0.125mg/kg injection after resection revealed the recurrence. The recurrence was not found in 4 animals with peripheral MMC 1.0mg/kg injection, but found in 60% of 5 animals with the MMC 0.5mg/kg injection after resection. In the animals with peripheral MMC 0.25mg/kg injection 2, 1 and 0 days before resection and with portal MMC 0.125mg/mg injection after resection, the recurrence was found in 83, 60 and 80% of 6, 5 and 5 respective animals. These results suggest that prophylactic injection of MMC for liver recurrence is more effective in portal than peripheral injection, but that the preoperative and peripheral injection has no efficacy.

Antisecretory and antiulcer effects of ebselen, a seleno-organic compound, in rats

The effects of ebselen (2-phenyl-1,2-benzisoselenazol-3(2H)-on), a metal-containing organic compound, on gastric secretion and gastric ulceration were examined in rats. Intraduodenal ebselen (30 to 300 mg/kg) significantly and dose-dependently inhibited gastric secretion in pylorus-ligated rats. Both aspirin- and water-immersion restraint stress-induced ulcers were significantly prevented by oral administration of ebselen at doses equivalent to the antisecretory doses. These results indicate that the antisecretory effect of ebselen underlies its antiulcer effect in these models.

Suppressive effect of doxorubicin on liver recurrence after resection of colonic VX2 cancer lesions: difference in efficacy according to the injection protocol

An animal model with liver cancer recurrence was induced by resecting colonic VX2 cancer lesions in 57 rabbits, and the effects of doxorubicin (ADR) on the recurrence were examined. Animals were divided into a control group and three chemotherapeutic groups: a portal injection group, to which ADR was injected into the portal vein after resection of the primary lesions; a peripheral injection group, to which ADR was injected into a peripheral vein after resection; and a preoperative injection group, to which an ADR dose of 0.5 mg/kg was peripherally injected 0, 1, and 2 days prior to resection followed by a portal injection of ADR 0.5 mg/kg after resection. The rate of liver recurrence was 100% in the control group, whereas it was 0% and 60% in the portal ADR 1.0 and 0.5 mg/kg injection groups, and 60% and 100% in the peripheral ADR 1.0 and 0.5 mg/kg injection groups. In the preoperative group, the rate was 0%, 100%, and 67% in the animals injected 2, 1, and 0 days prior to resection, respectively. These results suggest that portal injection or appropriate combinations of preoperative peripheral and portal injections of ADR are more effective than peripheral or portal injection alone in the suppression of liver recurrence.

Effect of DS-4574, a novel peptidoleukotriene antagonist with mast cell stabilizing action, on acute gastric lesions and gastric secretion in rats

DS-4574 is a peptidoleukotriene antagonist with mast cell stabilizing activity. In the present study, we studied the effects of this compound on gastric secretion and various acute gastric lesions in rats. Intraduodenal administration of DS-4574 at doses of 5 to 10 mg/kg significantly and dose-dependently inhibited gastric acid secretion in pylorus-ligated rats, but a further increase in the dose up to 50 mg/kg did not cause any further inhibition. Shay ulceration in response to pylorus ligation was dose-dependently prevented by DS-4574 (10-25 mg/kg, i.d.). Water-immersion restraint stress- and aspirin-induced gastric ulcers were also significantly prevented in a dose-related manner by oral pretreatment with DS-4574 (10-50 mg/kg). The lower doses of DS-4574 (1-10 mg/kg, p.o.) significantly and dose-dependently protected the gastric mucosa against the necrotizing action of either absolute ethanol or concentrated hydrochloric acid, indicating that this compound possesses a potent gastroprotective activity. These antiulcer and gastric protective effects of DS-4574 were more potent than those of cimetidine used as a reference drug. These findings suggest that DS-4574 is useful for peptic ulcer therapy, as well as for the therapy of various allergic diseases, including asthma.

[Establishment of an experimental model with a high frequency of liver metastasis and recurrence from gastric VX2 cancer: histological analysis of the developmental process of primary and metastatic cancer lesions]

An experimental model with a high frequency of liver metastases and recurrence was established by the non-resection and resection of gastric cancer lesions induced with implanting VX2 cancer cells into the stomach of 35 rabbits. The frequency of liver metastases was 0% on Days 7 and 14, 40% on Day 21 and 60% on Day 28 in the non-resection group. In the resection group, primary lesions were resected on Days 7, 10 and 14, and the metastases were found in all the animals 14 days after the resection on Day 14, though they did not occur in every animal 18 and 21 days after the resection on Days 10 and 7. The metastatic lesions were found in the peri-lobular area, accompanied by cancer emboli in the interlobular veins. Vascular invasion was found in almost all (90%) the primary lesions of animals with liver metastases or recurrence. These results suggest that hepatic micrometastases occur between 10 and 14 days after implantation, and that vascular invasion plays an important role in the formation and extension of liver metastases or recurrence. They also suggest that this model is utilized as a useful tool for studying many aspects of liver metastases or recurrence in gastric cancer.

[The effect of age and gender on the effect of midazolam as intramuscular premedicant]

This study was designed to quantify the appropriate dose of midazolam relating to age and gender for intramuscular premedication. Three hundred and eighty-six consecutive patients (15-83 years) received midazolam (2.5-5.5 mg) with atropine 30 minutes prior to surgery. The perioperative effects of midazolam on arterial pressure as well as heart rate, SpO2 and amnesic effects of regional anesthesia were evaluated in patients divided to 10-year age intervals. Reduction of arterial pressure correlated with preanesthetic values (r = 0.515, P less than 0.01). Especially in those over 60 years, we observed significant reductions. Besides, compared with the males, the reduction was smaller in females. On the arrival at the operating room, this reduction recovered slightly, but preanesthetic hypertension was still attenuated effectively. After age 70, the SpO2 was lower, while the amnesic effect during regional anesthesia was significantly prominent. Amnesic effect correlated more with the dose than the dosage determined by body weight. Younger female patients required larger dosage determined by body weight than the corresponding male. As age increases, dose adjustment should be made mostly on the basis of age, and its adjustment on the basis of body weight should be made with great caution. In this study, we determined the appropriate dose of midazolam, 5 mg for those males younger than 60 years and females below 50 years, and 3-3.5 mg for those older than 80 years.

Carcinoembryonic antigen levels of peripheral and draining venous blood in patients with colorectal cancer. Correlation with survival

Correlations between preoperative carcinoembryonic antigen (CEA) levels of peripheral (p-CEA) and draining blood (d-CEA), the CEA gradient between d-CEA and p-CEA (d-p CEA gradient) levels, and survival after resection of cancer lesions were examined in 94 patients with colorectal cancer. Survival rates of patients with normal p-CEA and d-CEA levels and d-p CEA gradient levels (less than 5 ng/ml) were significantly better than those of patients with abnormal levels (greater than or equal to 5 ng/ml), and the 5-year survival rates were, respectively, 62%, 69%, and 72% in the former and 42%, 41%, and 35% in the latter. The differences in the 5-year survival rates between patients with normal and abnormal d-p CEA gradient, d-CEA, and p-CEA levels were 37%, 28%, and 20%, respectively. Furthermore, the positive rates of d-CEA levels (64%) and d-p CEA gradient levels (48%) were higher than that of p-CEA levels (36%). However, some significant differences in background variables also were found between the respective groups of patients with normal and abnormal p-CEA and d-CEA levels and d-p CEA gradient levels. These results suggest that patients with poor prognoses are examined more effectively by determining their d-p CEA gradient and d-CEA levels than their p-CEA levels, and that CEA may be expressed as a quantitative sum total of various pathophysiologic variables of patients with colorectal cancer but not as an independent prognostic variable.

[Optimal dose of midazolam as premedicant for combined spinal and epidural anesthesia with midazolam sedation]

Sixty patients who underwent simple total hysterectomy under combined spinal and epidural anesthesia with midazolam sedation, were the subjects of a randomized double-blind comparison of intramuscular midazolam 4, 4.5 and 5 mg, and a dose determined by body weight as premedicants. Similar changes in arterial pressure and heart rate were observed. Furthermore sedation and the value of pulse oximetry on arrival were the same. Besides half the patients were amnesic during the procedure of regional approach. However the dose of premedicant was inversely correlated with the maintenance dose. The reduction of pulse oximetry reading on the induction was smaller, while the requirement of vasopressor occurred earlier following the larger dose of premedicant. In spite of the slower induction, the fall of pulse oximetry reading did not decrease. One hour after incision, the reduction of PaO2 was not dose related. In addition count of leucocyte and the level of blood glucose were unchanged. Premedicant determined by body weight was not correlated with the induction dose and amnesic effect. Our findings suggest midazolam 5 mg intramuscularly is the more preferable dose, but careful attention on arterial pressure is required.

Ouabain-insensitive, vanadate-sensitive K(+)-ATPase of rat distal colon is partly similar to gastric H+,K(+)-ATPase

A membrane fraction from rat distal colon contained both ouabain-sensitive and -insensitive K(+)-ATPase activities, which were measured under Na(+)-free conditions. About 38% of the ouabain-insensitive K(+)-ATPase activity was inhibited by vanadate. It was determined whether the ouabain-insensitive, vanadate-sensitive K(+)-ATPase in the colon is similar or identical to gastric H+,K(+)-ATPase. This colonic K(+)-ATPase activity was inhibited completely by monoclonal antibody HK4001, which inhibits the hog gastric H+,K(+)-ATPase activity but not Na+,K(+)-ATPase or Ca(2+)-ATPase. The colonic ATPase activity was inhibited partly by SCH 28080, which is a specific reversible inhibitor of gastric H+,K(+)-ATPase. The colonic ATPase activity was stimulated by low concentrations of K+ (its half-maximal stimulating concentration was 1 mM) and inhibited by high concentrations of K+ (its half-maximal inhibiting concentration was 10 mM), indicating that high and low K+ affinity sites are present in the colonic enzyme as in gastric H+,K(+)-ATPase and that this enzyme is not fully operative under normal physiological conditions. Two other monoclonal antibodies, which inhibit the gastric H+,K(+)-ATPase activity, did not inhibit the colonic K(+)-ATPase activity. The present results suggest that the colonic ouabain-insensitive K(+)-ATPase is partly similar but not identical to the gastric H+,K(+)-ATPase.

[Cushing's syndrome found during long-term glucocorticoid treatment of rheumatoid arthritis in an elderly woman]

A 69-year-old female patient had been treated with glucocorticoid for eight years because of rheumatoid arthritis. She showed characteristic Cushingoid features such as central obesity, moon face, and fragility of skin and vessels. She was disabled because of spinal compression fracture and muscle weakness. The blood pressure was 186/100 mmHg and the laboratory tests revealed serum K: 2.8 mEq/l, WBC: 15, 510/mm3, total cholesterol: 310 mg/dl. These suggested that she had iatrogenic Cushing's syndrome. After discontinuation of glucocorticoid, however, the serum cortisol level remained high. This fact prompted us to conduct further examinations for Cushing's syndrome. Oral dexamethasone administration did not suppress the plasma cortisol level and a left adrenal adenoma was found on abdominal CT scan. Because of the presence of bleeding diathesis, operation for adenoma was contraindicated. Though we tried to treat her with metyrapone, trilostane or opeprim (OP'-DDD), we had to abandon specific treatment because of severe side effects such as acute adrenal dysfunction and gastrointestinal problems. Decrease in the endogenous cortisol level after metyrapone treatment caused exacerbation of symptoms of rheumatoid arthritis. This is a peculiar case in which the long-term administration of glucocorticoid for rheumatoid arthritis might have concealed Cushing's syndrome, and conversely the increased intrinsic adrenal steroid hormone might have suppressed the activity of the rheumatoid arthritis.

Reassessment of plasma angiotensins measurement: effects of protease inhibitors and sample handling procedures

Characterization of C- and N-terminal forms of angiotensin (Ang) peptides mandated assessment of methods to determine plasma levels. 125I-Ang I, 125I-Ang II, and 125I-Ang(1-7) were added to blood samples in the presence of protease inhibitors. Ethylenediaminetetraacetic acid (EDTA) inhibited the conversion of 125I-Ang I to 125I-Ang II. o-Phenanthroline and EDTA (EDTA + o-Ph) did not eliminate [des-Asp1] fragments or 125I-Ang(1-7). The combination of EDTA + o-Ph and pepstatin A or 4-(chloromercuri) benzoic acid (PCMB) significantly reduced 125I-Ang(1-7) generation. Only PCMB plus EDTA + o-Ph eliminated [des-Asp1] fragments. Authentic plasma values of Ang peptides require the correct choice of protease inhibitors.

Converting enzyme inhibitors regressed cardiac hypertrophy and reduced tissue angiotensin II in spontaneously hypertensive rats

To examine the role of the tissue renin-angiotensin system in left ventricular hypertrophy, converting enzyme inhibitors were administered orally to 12-week-old male spontaneously hypertensive rats (SHR) for 4 weeks, and cardiac tissue angiotensin II was measured. Treatment with enalapril (10 mg/kg per day) and trandolapril (1 mg/kg per day) lowered systolic blood pressure, left ventricular weight and left ventricular angiotensin II content. Plasma angiotensin II concentration was increased by the treatment with enalapril whereas trandolapril did not cause any change. There was significantly positive correlation between left ventricular weight and angiotensin II content. Because angiotensin II promotes cell proliferation, these results suggest that cardiac tissue angiotensin II, rather than circulating angiotensin II, may account for the pathophysiology of left ventricular hypertrophy in SHR.