Telomerase in hepatocellular carcinogenesis

Despite the recent advances in diagnostic techniques of HCC, diagnosis of HCC is still difficult and ambiguous when HCC is small and of the well differentiated type. The results presented here demonstrated that strong telomerase activity was frequently detected in HCC irrespective of the stage or size of the nodules but neither in non-tumor diseased liver nor in normal liver. Telomerase activity determination can be a useful additional tool for the diagnosis of early well-differentiated HCC.

Evidence that endogenous GRP in rat stomach mediates omeprazole-induced hypergastrinemia

To investigate the physiological role of endogenous gastrin-releasing peptide (GRP) in regulating the release of gastrin, we evaluated the response of intragastric pH, gastrin, and GRP after omeprazole treatment in rats. A significant elevation of the plasma level of GRP (P < 0.01) and a significant reduction of the antral content of GRP (P < 0.05) were observed after the administration of 100 mg/kg omeprazole. The antral content of GRP was significantly decreased 12 h after omeprazole administration and thereafter gradually returned to control levels. Peak values for intragastric pH and plasma GRP were observed 3 h after omeprazole administration and before the peak of serum gastrin. The bombesin antagonist [D-Phe6]-bombesin-(6,13)-methyl ester significantly inhibited gastrin release after omeprazole treatment (P < 0.05). These observations indicate that omeprazole-induced inhibition of acid secretion stimulates the release of GRP and suggest that the secretion of GRP induced by omeprazole may stimulate the secretion of gastrin, at least in the early phase.

Response of conductance and resistance vessels of the coronary artery to intracoronary isosorbide dinitrate in patients with variant angina

To elucidate the response of conductance and resistance vessels of the coronary artery after intracoronary isosorbide dinitrate (ISDN), we evaluated 11 patients with variant angina and 13 controls with a Doppler guidewire. Epicardial arterial diameter increased significantly after ISDN in patients with variant angina while it did not change significantly in the controls. Coronary diastolic flow velocity increased significantly in controls (p < 0.05), but was unchanged in patients with vasospastic angina. Coronary flow volume increased from 23.8 +/- 18.6 to 46.5 +/- 28.4 ml/min in patients with vasospastic angina as well as in the controls from 32.2 +/- 24.2 to 54.7 +/- 44.4 ml/min. Coronary resistance did not differ between the two groups before or after the injection of ISDN. Conductance vessels were dilated to a greater extent in the patients with variant angina. However, the response of resistance vessels did not differ significantly between the two groups.

Radiofrequency catheter ablation for a patient with Wolf-Parkinson-White syndrome associated with sustained atrial tachycardia

Successful catheter ablation for a patient with both Wolff-Parkinson-White syndrome and sustained atrial tachycardia has not been reported. We describe a patient with Wolff-Parkinson-White syndrome associated with sustained atrial tachycardia, in whom an atrioventricular accessory pathway and an intra-atrial reentrant circuit were successfully ablated in a single session. Radiofrequency catheter ablation for the left-sided atrioventricular accessory pathway was performed via the trans-septal approach. Catheter ablation for the atrial tachycardia was achieved in the right atrium where the earliest and fractionated atrial activation was obtained. Catheter ablation for multiple lesions during a single session is feasible.

Expression of cripto in human gall bladder lesions

The expression of cripto, a member of the epidermal growth factor (EGF) family, was examined by immunohistochemistry in benign lesions and carcinomas of the gall bladder. Cripto expression was detected in 6 (67 percent) of 9 hyperplasias, 4 (58 percent) of 7 adenomas, and 89 (68 percent) of 132 adenocarcinomas of the gall bladder. The degree of cripto expression was not correlated with depth of tumour invasion, tumour stage or patient prognosis. The incidence of cases with cripto expression was significantly higher in papillary and well-differentiated adenocarcinomas (positive 73 percent; strongly positive 38 percent) than in moderately and poorly differentiated adenocarcinomas (positive 54 percent; strongly positive 17 percent) (P < 0.05). These results suggest that cripto expression may not relate to progression in gall bladder carcinomas, but may be associated with tumour differentiation.

Method for quantitative assessment of transformation of non-micellar cholesterol carriers in model bile systems

Aggregation and fusion of non-micellar particulate species, such as unilamellar vesicle and phospholipid lamellae, are believed to precede the nucleation of cholesterol crystals in bile. However, little is known about the time sequence relationship between transformation of non-micellar particles and the initial appearance of cholesterol crystals, as no adequate technique is available for assessing such transformations quantitatively. We have developed a novel method for quantitatively estimating vesicle transformation in supersaturated model bile systems, using a spectrophotometric technique to determine the time sequence relationship between such transformations and cholesterol crystal nucleation. We also investigated the potency of a given effector substance on this transformation. This method permits simultaneous quantitative determination of vesicle aggregation and of cholesterol crystal growth. Maximal vesicular aggregation as determined from turbidity, coincided with initiation of cholesterol crystal nucleation. The addition of divalent cations, Ca2+ and Mg2+, to the model bile solutions promoted vesicle aggregation and cholesterol crystal nucleation and growth. In contrast, apolipoproteins A-1 and A-2 retarded such processes. These data were highly reproducible and reliable. The method described is easy to perform, provides reproducible results and permits the determination of the potency of effector substances on vesicle transformation and on the nucleation of cholesterol crystals.

Modulation of target tissue response to angiotensin II and sodium sensitivity in Japanese patients with essential hypertension

"Non-modulators" are essential hypertensive patients who fail to modulate an adrenal response, renovascular response, or both, to angiotensin II (Ang II). The aim of the present study was to characterize "non-modulators" among Japanese patients with normal-renin essential hypertension and to determine whether non-modulation is related to sodium sensitivity of blood pressure. The increase in plasma aldosterone concentration (PAC response) and the decrease in renal plasma flow (RPF response) in response to Ang II infusion (3 ng/kg/min) were assessed in 15 Japanese patients with essential hypertension who received a high sodium diet (250 mEq/d) followed by a low sodium diet (10 mEq/d). The subjects were divided into two groups (6 modulators and 9 non-modulators) based on their ability to modulate the PAC response during sodium restriction. There was no significant difference between modulators and non-modulators in electrolyte balance or in plasma Ang II levels on either diet. Changes in the PAC response during sodium restriction were significantly correlated with the change in mean blood pressure during sodium restriction (r = -0.67, p < 0.01), while changes in the RPF response were not. RPF responses in both groups decreased during sodium restriction, although an effect on the RPF response in non-modulators was unexpected. These results suggest that non-modulators do exist among Japanese patients, but that this defect does not involve both the adrenal gland and the kidney. Apparently, only non-modulation of the adrenal response is involved in the mechanism of sodium sensitivity.

Lecithin hydrophobicity modulates the process of cholesterol crystal nucleation and growth in supersaturated model bile systems

The present study was performed to determine whether the degree of lecithin hydrophobicity regulates bile metastability and, therefore, affects the process of cholesterol crystallization. Supersaturated model bile (MB) solutions were prepared with an identical composition on a molar basis (taurocholate/lecithin/cholesterol, 73:19.5:7.5; total lipid concentration 9 g/dl) except for the lecithin species; egg yolk phosphatidylcholine, soybean phosphatidylcholine, 1-palmitoyl-2-linoleoyl-sn-phosphatidylcholine, dilinoleoyl phosphatidylcholine and dipalmitoyl phosphatidylcholine. Each MB solution was incubated and sequentially examined. Video-enhanced contrast microscopy demonstrated that the rate of vesicular aggregation and fusion correlated with the degree of lecithin hydrophobicity, and that the rate of cholesterol crystal nucleation correlated with the degree of lecithin hydrophilicity. In MBs containing less hydrophobic lecithin, needle-like crystals developed and transformed into mature plate-like crystals, whereas classical plate-like crystals were consistently observed in MBs composed of hydrophobic lecithin. Laser-diffraction particle size analysis demonstrated that the increase in lecithin hydrophobicity enlarged the vesicle dimension, enhancing its cholesterol-holding capacity. Correlation between vesicular cholesterol packing density and lecithin hydrophobicity suggests that the process of bile cholesterol nucleation and growth is regulated, in part, by acyl chain unsaturation in lecithin. Since the composition of biliary lecithins is responsive to dietary manipulations, this study provides new insights into the prevention of cholesterol gallstones.

Effects of insulin on calcium metabolism and platelet aggregation

The influence of insulin on platelets in vitro has not been exhaustively investigated. To clarify whether insulin affects Ca2+ metabolism in platelets directly or through alteration of other systems regulating intracellular Ca2+ homeostasis, we examined the effect of insulin both alone and in combination with prostaglandin E1 on platelet aggregation and Ca2+ metabolism. Incubation of rat platelets with insulin reduced thrombin-induced Ca2+ influx but did not change thrombin-evoked release of Ca2+ from internal stores or the size of internal Ca2+ stores. The interactive effects of insulin with prostaglandin E1 were only additive, and insulin did not augment the effects of prostaglandin E1 on platelet Ca2+ metabolism. In contrast, insulin did not inhibit thrombin-induced platelet aggregation but did augment inhibition of platelet aggregation by prostaglandin E1. Our results suggest that insulin inhibits platelet function by both prostaglandin E1-dependent and -independent mechanisms.

K-ras and p53 mutations in stage I gallbladder carcinoma with an anomalous junction of the pancreaticobiliary duct

BACKGROUND

An anomalous junction of the pancreaticobiliary duct (AJPBD) was thought to be an important risk factor for gallbladder carcinoma in Japan. In this report, we compared K-ras and p53 mutations in Stage I gallbladder carcinomas (GC) of patients with AJPBD with those in patients without AJPBD:

METHODS

We examined 6 GC of patients with AJPBD and 20 GC of patients without AJPBD: Immunohistochemistry was performed for p53 protein. K-ras and p53 mutations were examined using genomic DNA extracted from the cancer regions. The methods of polymerase chain reaction (PCR) single strand conformation polymorphism analysis were performed for mutations in exons 5-8 of p53. The methods of PCR restriction fragment length polymorphism were performed for mutation in codon 12 of K-ras.

RESULTS

p53 positivity was 67% in GC of patients with AJPBD and 65% in GC of patients without AJPBD: p53 mutations were found in exons 7 and 8 in GC of patients with AJPBD and in exons 5, 6, and 7 in GC of patients without AJPBD: The incidence of K-ras mutation in GC of patients with AJPBD (50%) was greater than that in patients without AJPBD (6%) (P < 0.05).

CONCLUSIONS

These results suggest that K-ras mutation may be important in the early stage of carcinogenesis of the gallbladder mucosa with AJPBD, and that p53 mutations may also contribute to the early stage of carcinogenesis of the gallbladder mucosa, regardless of AJPBD:

Potentiation of the intracellular Ca2+ response to arginine vasopressin by increased cytosolic-free Mg2+ in rat vascular smooth muscle cells

Although the inhibitory effects of extracellular Mg2+ on Ca2+ influx are well established, little is known about the effects of intracellular Mg2+ on Ca2+ handling. In the present study, the effects of cytosolic-free Mg2+ concentration in the physiological (submillimolar) range on Ca2+ handling were investigated after stimulation of rat vascular smooth muscle cells with arginine vasopressin. Cytosolic Mg2+ was manipulated by culturing cells in medium containing different Mg2+ concentrations. Peak cytosolic-free Ca2+ concentration responses to arginine vasopressin (1 mumol/1) were measured in the presence and absence of external Ca2+. The results suggest that an increase in cytosolic-free Mg2+ concentration increases both Ca2+ discharge from intracellular stores and Ca2+ influx, whereas a decrease in intracellular Mg2+ attenuates Ca2+ influx.

High frequency of p53 gene mutation in adenocarcinomas of the gallbladder

p53 mutations in adenocarcinomas of the gallbladder were analyzed by deoxynucleotide sequencing of the gene. Of 23 cases, 16 (70%) harbored 18 missense mutations in exon 5, 6, or 8 of the p53 gene. The characteristics of the p53 mutation spectrum observed in gallbladder carcinomas were (a) frequent mutations at an A:T pair [10 (55%) of 18 mutations], (b) high transversion incidence [12 (66%) of 18 mutations], and (c) only one mutation at the CpG site. The immunohistochemical study revealed that 36 (55%) of 65 cases showed an abnormal accumulation of p53 immunoreactivity, and 12 (52%) of 23 cases had p21 expression. No statistical correlation was observed between p53 and p21 immunoreactivity. These results suggest that p53 mutations may confer the carcinogenesis of the adenocarcinoma of the gallbladder with the specific mutation spectrum of p53.

Nitric oxide production by coronary conductance and resistance vessels in hypercholesterolemia patients

NG-monomethyl-L-arginine (L-NMMA), a specific inhibitor of nitric oxide (NO) synthesis, was used to investigate the effects of inhibition of NO synthesis on the coronary conductance and resistance vessels in hypercholesterolemic patients. Acetylcholine (3 and 30 micrograms/min) was administered to 10 hypercholesterolemic and 10 control patients before and after L-NMMA (25 micromol/min) infusion. Epicardial coronary diameter was measured by quantitative angiography, and coronary blood flow (CBF) was derived from Doppler flow-velocity and coronary diameter measurements. In hypercholesterolemic patients, acetylcholine-induced dilation of epicardial arteries was attenuated, and the percentage increase in CBF caused by acetylcholine was smaller than that in control patients. L-NMMA attenuated acetylcholine-induced dilation of epicardial arteries in control patients. L-NMMA had no effect on CBF responses to acetylcholine in both patient groups. L-NMMA significantly decreased the baseline coronary diameter and CBF in both groups. These results indicated that hypercholesterolemia impaired the acetylcholine-induced dilation of the conductance and resistance coronary vessels. This impairment in the conductance vessels was dependent on NO production; that of resistance vessels was not. The basal release of NO in conductance and resistance vessels was preserved in hypercholesterolemic patients.

Effect of erythropoietin treatment on blood pressure and intracellular cation concentrations in maintenance hemodialysis patients

To assess the effect of recombinant human erythropoietin (EPO) on the factors regulating blood pressure (BP), we determined the hemoglobin level (Hgb), blood viscosity (BV), plasma renin activity (PRA), plasma concentrations of aldosterone (PAC), adrenaline (Ad), noradrenaline (NAd), and atrial natriuretic peptide (ANP), and serum and intracellular concentrations of cations before and after 3 months of EPO treatment (40 units/kg/week of EPO intravenously after each hemodialysis session) in 11 patients undergoing maintenance hemodialysis. Intracellular sodium concentration ([Na+]i) was measured using erythrocytes with flame photometry. EPO treatment was associated with significant increases in Hgb (7.1 +/- 1.4 to 8.4 +/- 1.8 g/dl, p<0.01), mean BP (103 +/- 11.4 to 116 +/- 19.9 mmHg, p<0.01), [Na+]i (4.99 +/- 0.78 to 6.22 +/- 0.96 mmol/l, p<0.01) and BV (1.39 +/- 0.14 to 1.53 +/- 0.18 c.p., p<0.05), but no significant alteration in PRA, PAC, Ad, NAd, ANP, or in the serum concentration of Na+, K+, and Ca2+. The changes in mean BP (deltaMBP) were significantly correlated with delta[Na+]i (R=0.676, p=0.022) and deltaBV (R=0.668, p=0.034), but not with deltaHgb. By multiple regression analysis, delta[Na+]q and deltaBV independently contributed to deltaMBP; deltaMBP=2.27 X delta[Na+]i+32.2 X deltaBV +3.37 (R=0.695). These data suggest that intracellular sodium accumulation as well as increased blood viscosity may be independently involved in the blood pressure elevation after EPO treatment in patients under maintenance hemodialysis. We found no evidence supporting a role of circulating hormonal factors, such as the renin-angiotensin system, adrenaline, or ANP, in the change in blood pressure.

Effects of pirenzepine on omeprazole-induced gastrin gene expression in rat antral tissues

Pirenzepine has inhibitory effects on gastrin secretion both in vivo and in vitro. The aim of this study was to determine the mechanism responsible for the suppression of omeprazole-induced hypergastrinemia that occurs with pirenzepine treatment. The effects were measured in rats treated with oral omeprazole plus intraperitoneal pirenzepine or saline once daily for seven days in the antrum. The serum gastrin level increased significantly by more than sixfold with omeprazole treatment; additional treatment with pirenzepine suppressed this increase by 48%. Pirenzepine treatment did not change the level of gastrin mRNA but significantly increased the level of somatostatin mRNA. Combination treatment with omeprazole plus pirenzepine significantly decreased the gastrin mRNA level to half and significantly increased the somatostatin mRNA level up to 1.4-fold of the levels achieved with omeprazole treatment alone. These results suggest that the stimulatory effect of omeprazole on gastrin synthesis is partially blocked by pirenzepine via mediation of somatostatin synthesis in the antrum.

Platelet Ca2+ is not increased in stroke-prone spontaneously hypertensive rats: comparative study with spontaneously hypertensive rats

We have reported that cytosolic Ca2+ concentration ([Ca2+]i) is increased in platelets from spontaneously hypertensive rats (SHR) in both basal and thrombin-stimulated conditions. To determine whether the correlation between blood pressure and cellular Ca2+ metabolism exists in stroke-prone SHR (SHRSP), we investigated Ca2+ handling using fura 2 and aggregation response in platelets of 12- to 13-week-old male SHRSP, SHR, and Wistar-Kyoto rats (WKY). Systolic pressure was highest in SHRSP and lowest in WKY (213 +/- 8, 172 +/- 7, and 135 +/- 5 mm Hg, respectively). Basal [Ca2+]i was significantly higher in SHR than WKY (45.9 +/- 4.5 versus 41.2 +/- 4.8 nmol/L, P<.05), and that in SHRSP (40.2 +/- 2.8 nmol/L) was similar to that in WKY. Thrombin (0.1 IU/mL)-stimulated [Ca2+]i rise was greater in SHR and smaller in SHRSP than in WKY in the presence of extracellular Ca2+ (530 +/- 50 and 408 +/- 52 versus 475 +/- 50 nmol/L, respectively; P<.05). The recovery rate from the peak [Ca2+]i response to thrombin was greatest in SHRSP and least in WKY. Ionomycin (5 micromol/L)-stimulated [Ca2+]i rise was similar in WKY, SHR, and SHRSP (731 +/- 97, 743 +/- 88, and 683 +/- 70 nmol/L, respectively). Thrombin-induced maximum platelet aggregation response was higher in SHR and lower in SHRSP than WKY (82 +/- 4 percent and 61 +/- 15 percent versus 73 +/- 6 percent, respectively; P<.05). In contrast to SHR, basal [Ca2+]i in SHRSP was similar to that in WKY, and thrombin-stimulated [Ca2+]i was attenuated. These result suggest that platelet Ca2+ handling differs between SHR substrains and that an increased [Ca2+]i is not obligatory in genetically hypertensive rats.

Immunocytochemical detection of p53 protein from pancreatic duct brushings in patients with pancreatic carcinoma

BACKGROUND

It is often difficult to distinguish pancreatic carcinoma preoperatively from chronic pancreatitis. Therefore, we have developed a new method of detecting p53 immunoreactivity in cytologic material obtained by endoscopic retrograde pancreatic duct brushing (ERPDB).

METHODS

Twenty-eight patients with prominent strictures of the main pancreatic duct demonstrated by pancreatography including 20 ductal cell carcinoma and 8 chronic pancreatitis were studied. The ability to distinguish between these two groups preoperatively by conventional cytologic examination was compared with p53 immunocytochemistry using ERPDB:

RESULTS

The sensitivity, specificity, and overall accuracy of conventional cytologic examination in distinguishing ductal cell carcinoma from chronic pancreatitis were 60%, 100%, and 71% respectively. In comparison, the sensitivity, specificity, and overall accuracy of p53 immunocytochemistry in distinguishing were 90%, 100%, and 93%, respectively. The sensitivity of p53 staining of specimens from patients with carcinoma of the body or tail of the pancreas (90%) was the same for those with tumors of the head of the pancreas (90%).

CONCLUSIONS

These results suggest that p53 immunocytochemistry using ERPDB in conjunction with conventional cytologic examination can help differentiate ductal cell carcinoma from chronic pancreatitis preoperatively.

Pathology and cellular kinetics of gallbladder with an anomalous junction of the pancreaticobiliary duct

OBJECTIVES

Anomalous junction of the pancreaticobiliary duct (AJPBD) is thought to be an important risk factor for gallbladder carcinoma in Japan. In this report, we examine histopathology and cellular kinetics of gallbladder mucosae of patients with AJPBD and the possible risk of gallbladder carcinoma.

METHODS

We examined 62 gallbladders from patients with AJPBD (group A), 16 gallbladder carcinomas from patients with AJPBD (group B), 60 gallbladder carcinomas from patients without AJPBD (group C), and six normal gallbladders from patients without AJPBD (group D). Histopathology, mucosal heights, and proliferative cell nuclear antigen-labeling index were obtained from routinely processed tissue specimens.

RESULTS

The incidence of hyperplastic changes in group A and in the noncancerous regions (NCRs) of group B was greater than in the NCRs of group C (p < 0.05). The incidence of dysplastic changes in the NCRs of group B was greater than in the NCRs of group C (p < 0.05). The mucosal heights in group A and in the NCRs of group B were higher than in the NCRs of group C (p < 0.05). A high proliferative cell nuclear antigen-labeling index was observed in group A and in the NCRs of group B, where hyperplastic changes were frequently observed.

CONCLUSIONS

These results suggest that a sequence of hyperplastic changes with a corresponding increase in cellular kinetics with progression through dysplasia to carcinoma may be important in carcinogenesis in gallbladders of patients with AJPBD. AJPBD itself may be a possible risk for gallbladder carcinoma.

Helicobacter pylori infection is the major risk factor for atrophic gastritis

OBJECTIVE

To evaluate the association of both Helicobacter pylori (Hp) infection and advancing age with increased prevalence of atrophic gastritis.

METHODS

Two hundred and thirty-eight subjects who had no esophagitis, peptic ulcers, or malignancies in the upper gastrointestinal tract were divided into three groups according to age: group A, < 30 yr; group B, 30-49 yr; group C, > or = 50 yr. Two biopsy specimens were obtained from the lesser curvature of the antrum and two from the anterior and posterior walls of the fundus to assess the degree of gastritis and histological evidence of Hp infection. Hp infection was evaluated by Giemsa staining and serum IgG antibodies. Serum gastrin (SG) and pepsinogen (PG) were determined by radioimmunoassay.

RESULTS

In all age groups, the prevalence of atrophic gastritis was significantly more common in subjects with evidence of Hp infection. In Hp-positive subjects, the prevalence of atrophic gastritis increased with advancing age. Atrophic gastritis was extremely rare, regardless of age, in Hp-uninfected patients. SG increased, and PG I and the PG I:II ratio decreased with age in Hp-positive subjects. This trend was not apparent in Hp-negative subjects.

CONCLUSION

Our results suggest that Hp infection is a stronger predictor than advancing age for atrophic gastritis.

Inhibition of cell growth by transforming growth factor beta 1 is associated with p53-independent induction of p21 in gastric carcinoma cells

Cell cycle regulators such as cyclins, cyclin-dependent kinases (cdks) and their inhibitors control the growth of cells. SDI1/CIP1/WAF1/p21 is a potent inhibitor of G1 cdks, whose expression is induced by wild-type p53. To elucidate the mechanism of growth inhibition by transforming growth factor beta 1 (TGFbeta 1), we examined the effect of TGFbeta 1 on the expression of p21, G1 cyclins and cdks by human gastric cancer cell lines. TGFbeta 1 induced p21 expression and subsequently suppressed cdk2 kinase activity, followed by a reduction in phosphorylation of the product of the retinoblastoma tumor suppressor gene in TMK-1 cells, which are responsive to TGFbeta 1. Coimmunoprecipitation analysis demonstrated that TGFbeta 1 increased the level of p21 protein present in complexes with cdk2. In contrast, TGFbeta 1 did not induce p21 in TGFbeta 1-resistant MKN-28 cells. TGFbeta 1 did not affect the levels of p53 mRNA and protein in TMK-1 and MKN-28 cells, which contain mutated p53 genes. These mutated p53 complementary DNAs, when overexpressed, failed to activate transcription from the p21 promoter. Furthermore, TGFbeta 1 caused a reduction in the steady-state level of cyclin A protein concomitantly with inhibition of cdk2 kinase activity in TMK-1 cells. These results suggest that the growth inhibition of tumor cells by TGFbeta 1 is associated with p53-independent induction of p21, subsequent suppression of cdk activity and a decrease in cyclin A protein in TMK-1 cells.

Effects of pirenzepine on omeprazole-induced hypergastrinemia and acid suppression in peptic ulcer patients

Omeprazole effectively suppresses acid secretion, resulting in the long-term elevation of intragastric pH and serum gastrin level. Pirenzepine has been reported to inhibit gastrin secretion. This study was carried out to examine the effects of additional pirenzepine treatment on the hypergastrinemia and gastric acid suppression induced by omeprazole. Concentrations of serum gastrin and plasma somatostatin were measured in 28 peptic ulcer patients before treatment, after omeprazole treatment (20 mg/day) for 2 weeks, and after omeprazole and pirenzepine (100 mg/day) treatment for 2 weeks. The acid inhibitory effect of pirenzepine treatment in addition to omeprazole was evaluated by 24-h intragastric pH measurement in six healthy volunteers. Serum gastrin level was increased significantly, to 2.4-fold the pretreatment level, by omeprazole treatment. Additional treatment with pirenzepine suppressed serum gastrin level to 0.6-fold the omeprazole-treatment level. The serum somatostatin level was not altered significantly either by omeprazole treatment or by omeprazole and pirenzepine treatment. In healthy volunteers whose pH 3 holding time on 24-h intragastric pH monitoring was 70% by omeprazole treatment, omeprazole and pirenzepine treatment markedly increased the pH 3 holding time, to 89%. These findings suggest that pirenzepine is useful in reducing the undesirable effects of omeprazole-induced hypergastrinemia, i.e., the excessive trophic effect of omeprazole on the acid-secreting part of the stomach and the overstimulation of acid secretion. The additional pirenzepine treatment is also effective in suppressing acid secretion.

Cholecystokinin receptor antagonist, loxiglumide, inhibits invasiveness of human pancreatic cancer cell lines

Recently, cholecystokinin has been reported to be important in regulating the growth of pancreatic cancer. We investigated the effect of loxiglumide (LXG), a cholecystokinin receptor antagonist, on the invasiveness of two human pancreatic cancer cell lines. Cells were treated with LXG for 24 h, and examined in the invasion assay. The expression and activity of MMP-9 in supernatants from cancer cells were analyzed by Western blotting and zymogram. Interestingly, the invasiveness of cancer cells and expression of MMP-9 were decreased by LXG in a dose-dependent manner. LXG may be a useful therapeutic agent against pancreatic cancer.

Inhibition of lipid hydroperoxidation of low density lipoprotein by the Ca(2+)-channel and alpha 1-adrenoceptor antagonist monatepil maleate

The antioxidative effect of monatepil maleate (CAS 103379-03-9, AJ-2615), a new antihypertensive agent, was investigated by measuring its ability to inhibit copper-induced lipid hydroperoxidation of low density lipoprotein (LDL) and was compared with those of diltiazem (Ca(2+)-channel antagonist), prazosin (alpha 1-adrenoceptor antagonist), and probucol. The concentration of AJ-2615 required to inhibit copper-induced lipid hydroperoxidation of LDL by 50% (IC50) was 28 mumol/l. The IC50 values for diltiazem, prazosin, and probucol were > 1 mmol/l, > 1 mmol/l, and 17 mumol/l, respectively. These results indicate that AJ-2615 has the same potent antioxidative effect as probucol and suggest that a previously reported ability of AJ-2615 to inhibit the progression of atherosclerosis may be due to this antioxidative property. In addition, the dihydrodibenzothiepine ring of AJ-2615 may have an antioxidative functions.

[Clinical analysis on the course and prognosis of patients with Crohn's disease]

We analyzed 66 cases (47 males and 19 females) of Crohn's disease at Hiroshima University hospital from September 1975 to October 1994 to clarify the course and prognosis of Crohn's disease. The age at onset was 21.1 +/- 7.3 years old (mean +/- SD), terms between onset and diagnosis were 21.5 +/- 33.0 months (mean +/- SD) and observation period was 65.5 +/- 44.6 months (mean +/- SD). Sites of lesion were 18 ileum, 41 ileocolon and 7 colon. Thirty-one cases, 20 cases of which had intestinal obstruction, underwent surgical operation (12 ileum types, 18 ileocolic types, 1 colon type). The cumulative probability of surgery at one, five and ten years after onset of symptoms were 12.1%, 28.8% and 56.9%, respectively. As for cumulative probability of surgical operation at one, five and ten years after diagnosis were 25.8%, 36.7% and 74.4%, respectively. Results of the cumulative probability of surgery by anatomical involvement indicated that the ileum type had a statistically significantly higher risk than other types. In each analysis compliance to nutritional therapy was also an important prognostic factor. Overall, our results indicated that the site of lesion and the compliance to nutritional therapy were important factors which have an effect on the course and prognosis of Crohn's disease patients.

Angiotensin I-converting enzyme gene polymorphism and salt sensitivity in essential hypertension

We undertook the present study in 66 Japanese patients with essential hypertension to identify genetic factors associated with salt sensitivity. Patients were classified into salt-sensitive or salt-resistant groups on the basis of changes in their mean blood pressures from a week of a low salt diet (50 mmol/d) to a week of a high salt diet (340 mmol/d). Salt sensitivity and resistance were studied in relation to a 287-bp insertion/deletion (I/D) polymorphism of the angiotensin I-converting enzyme gene detected by a polymerase chain reaction method and the haptoglobin phenotype determined by polyacrylamide gel electrophoresis. Patients with the angiotensin I-converting enzyme gene genotype II were more apt to be salt sensitive than patients with the ID and DD genotypes, although plasma renin activity was similar in each group. The frequency of the I allele in the salt-sensitive group was significantly higher than that in the salt-resistant group (chi2 = 7.4, odds ratio = 2.78). However, there was no significant relationship between haptoglobin phenotype and salt sensitivity. These data suggest that an I/D polymorphism of the angiotensin I-converting enzyme gene is a genetic factor associated with salt sensitivity of blood pressure independently of plasma renin activity in Japanese patients with essential hypertension.

Renal response to L-arginine in salt-sensitive patients with essential hypertension

This study examined whether disturbances in nitric oxide formation contribute to renal dysfunction in salt-sensitive essential hypertensive patients. We evaluated the effects of intravenous administration of L-arginine (500 mg/kg given over 30 minutes) on systemic and renal hemodynamics in 23 patients with mild essential hypertension during 1 week of a low NaCl diet (50 mmol/d) followed by 1 week of a high NaCl diet (340 mmol/d). Patients were classified as salt sensitive (n=10) or salt resistant (n=13) based on salt-induced changes in their blood pressures. Salt loading increased renal vascular resistance but not renal plasma flow in salt-sensitive patients. The L-arginine-induced renovascular relaxation was significantly reduced by a high NaCl diet (renal vascular resistance: low NaCl -12.4 +/- 2.3% versus high NaCl -7.1 +/- 1.8%, P < .001) in salt-sensitive patients, whereas it was unchanged in salt-resistant patients. The increase in plasma cGMP in response to L-arginine was also reduced by a high NaCl diet in the salt-sensitive patients (low NaCl 49 +/- 7% versus high NaCl 36 +/- 8%, P < .05) but not in the salt-resistant patients (low NaCl 51 +/- 6% versus high NaCl 58 +/- 6%). These findings suggest that NaCl loading in salt-sensitive patients with mild essential hypertension reduces the ability of L-arginine to produce nitric oxide in the endothelium of the renal vasculature.

Flat-elevated colorectal neoplasms exhibit a high malignant potential

The potential of flat-elevated colorectal adenomas to undergo rapid malignant transformation and progression to invasive carcinoma is still under discussion. Therefore, a total of 130 colorectal neoplastic lesions > or = 1 cm in diameter were examined after endoscopic or surgical resection. Lesions were macroscopically classified into three categories: (1) flat elevation (22 lesions), superficially elevated lesion with a smooth surface; (2) granular laterally spreading tumor (GLST; 26 lesions), laterally spreading aggregates of nodules forming a lesion with granular surface, and (3) polypoid (82 lesions), pedunculated, subpedunculated and sessile polyps. The adenomatous component showed a tubulovillous architecture in 9/26 (35%) of GLST and 18/82 (22%) of polypoid lesions, however none of the flat-elevated lesions had a villous component (p <0.01; p <0.05). Carcinoma was present in 17/22 (77%) flat elevations, 37/82 (45%) polypoid lesions and 11/26 (42%) GLST (p <0.05). None of the carcinomas arising in GLST and only 1/37 (3%) of those developing in polypoid lesions were invasive carcinomas, but 4/17 (24%) carcinomas arising in flat elevations showed submucosal invasion. Moreover, while all 5 noncancerous flat elevations showed severe atypia, 17/82 (21%) polypoid lesions and 5/26 (19%) GLST showed moderate atypia. In conclusion, flat-elevated colorectal neoplasms have a high malignant potential and the role of these lesions as precursors of colorectal carcinomas deserves greater emphasis.

Flow-mediated vasodilation of human epicardial coronary arteries: effect of inhibition of nitric oxide synthesis

OBJECTIVES

This study sought to investigate the role of nitric oxide, an endothelium-derived relaxing factor, in flow-mediated vasodilation in human epicardial coronary arteries.

BACKGROUND

Endothelium-derived relaxing factors may be released from the coronary artery endothelium in response to increases in blood flow.

METHODS

We studied the effect of the nitric oxide synthesis inhibitor NG-monomethyl-L-arginine (L-NMMA) on the flow-mediated vasodilation of epicardial coronary arteries in 12 patients, using quantitative angiographic and Doppler flow velocity measurements. Adenosine at 100 micrograms/min was infused into the left anterior descending coronary artery to test the dilator response of the proximal artery to increases in blood flow. Acetylcholine at 3 and 30 micrograms/min was infused into the left coronary ostium to determine endothelium-dependent vasodilation of the proximal left anterior descending artery. Adenosine and acetylcholine were infused before and after the intracoronary infusion of L-NMMA (25 mumol/min for 5 min).

RESULTS

Infusion of L-NMMA caused a significant decrease in the baseline diameter of the proximal left anterior descending artery (from 2.90 +/- 0.14 to 2.74 +/- 0.13 mm [mean +/- SEM], p < 0.01). Adenosine increased coronary blood flow before and after L-NMMA (+399.5 +/- 27.5% and +511.9 +/- 33.3%, respectively). Flow-mediated vasodilation was observed in the proximal left anterior descending artery before and after L-NMMA (+9.2 +/- 1.5%, p < 0.01 and +8.6 +/- 2.1%, p < 0.01, respectively). A dose of 3 micrograms/min of acetylcholine significantly dilated the proximal left anterior descending artery before L-NMMA (+7.6 +/- 1.0%, p < 0.01), but acetylcholine-induced vasodilation was attenuated after L-NMMA (-1.8 +/- 1.0%).

CONCLUSIONS

Our data suggest that nitric oxide modulates basal coronary artery tone but that mediators other than nitric oxide may be responsible for the flow-mediated vasodilation of human epicardial coronary arteries.

Modulation of Ca2+-activated K+ channels by Mg2+ and ATP in frog oxyntic cells

Ca2+-activated K+ channels in the basolateral plasma membrane of bullfrog oxynticopeptic cells are intimately involved in the regulation of acid secretion. Patch-clamp techniques were applied to study the regulating mechanism of these channels. In the excised inside-out configuration, intracellular Mg2+ decreased channel activity in a dose-dependent manner. In the absence of Mg2+, administration of adenosine 5'-trisphosphate (ATP) to the cytoplasmic side also inhibited channel activity. On the other hand, in the presence of Mg2+, addition of ATP markedly increased channel activity. At a fixed concentration of free Mg2+, the Mg-ATP complex caused channel activation and shifted the dose response relationship between channel activity and the intracellular Ca2+ concentration to the left. A nonhydrolysable ATP analogue, adenosine 5'-[beta,gamma-imido]triphosphate (AMP-PNP) adenylyl [beta,gamma-methylene]diphosphate (AMP-PCP), could not substitute for ATP in channel activation, but a hydrolysable ATP analogue, adenosine 5'-O-(3-thiotriphosphate) (ATP[gammaS]) could do so. Furthermore, application of alkaline phosphatase to the cytoplasmic side inhibited channel activity. These results demonstrate that Ca2+-activated K+ channels are regulated by Mg2+ and ATP, and suggest that a phosphorylation reaction may be involved in the regulation mechanism of these channels.

K-ras and p53 mutations in stage I gallbladder carcinoma with an anomalous junction of the pancreaticobiliary duct

BACKGROUND

An anomalous junction of the pancreaticobiliary duct (AJPBD) was thought to be an important risk factor for gallbladder carcinoma in Japan. In this report, we compared K-ras and p53 mutations in Stage I gallbladder carcinomas (GC) of patients with AJPBD with those in patients without AJPBD:

METHODS

We examined 6 GC of patients with AJPBD and 20 GC of patients without AJPBD: Immunohistochemistry was performed for p53 protein. K-ras and p53 mutations were examined using genomic DNA extracted from the cancer regions. The methods of polymerase chain reaction (PCR) single strand conformation polymorphism analysis were performed for mutations in exons 5-8 of p53. The methods of PCR restriction fragment length polymorphism were performed for mutation in codon 12 of K-ras.

RESULTS

p53 positivity was 67% in GC of patients with AJPBD and 65% in GC of patients without AJPBD: p53 mutations were found in exons 7 and 8 in GC of patients with AJPBD and in exons 5, 6, and 7 in GC of patients without AJPBD: The incidence of K-ras mutation in GC of patients with AJPBD (50%) was greater than that in patients without AJPBD (6%) (P < 0.05).

CONCLUSIONS

These results suggest that K-ras mutation may be important in the early stage of carcinogenesis of the gallbladder mucosa with AJPBD, and that p53 mutations may also contribute to the early stage of carcinogenesis of the gallbladder mucosa, regardless of AJPBD:

[Clinicopathologic evaluation on colorectal laterally spreading tumor (LST)]

Clinicopathologic characteristics of 92 colorectal laterally spreading tumors (LST) endoscopically or surgically resected were examined. Lesions were macroscopically classified into two categories according to their surface structure :(1) granular type (G type, 47 lesions), (2) flat type (F type, 45 lesions). The size (maximum diameter) of G type lesions was 24.7 +/- 11.3 mm (Mean +/- SD) and that of F type lesions was 14.2 +/- 7.4 mm. The size of G type lesions was significantly larger than that of F type lesions (p < 0.01). Among G type lesions, cancerous lesion was present in 2 (25.0%) of 8 lesions 10-14 mm in diameter, 2 (22.2%) of 9 lesions 15-19 mm in diameter and 19 (63.3%) of 30 lesions more than 20mm in diameter. Regarding F type lesions, cancerous lesion was present in 15 (46.9%) of 32 lesions 10-14 mm in diameter, 4 (80.0%) of 5 lesions 15-19 mm in diameter and 8 (100%) of 8 lesions more than 20mm in diameter. The incidence of carcinoma in F type lesions was higher than that in G type lesions irrespective of size. F type lesions with carcinoma showed a trend toward a higher frequency of submucosal invasion and F type lesions with adenoma revealed tendency of showing severe atypia in comparison with G type lesions. The adenomatous component of LST showed a tubulo-villous architecture in 13 (28.3%) of 46 G type lesions, however none of F type lesions had a tubulo-villous component. These results indicated that clinicopathologic characteristics of F type are obviously different from G type. Furthermore, F type had a higher malignant potential than G type and is thought to have a more important role as a precursor of colorectal carcinoma than G type.

Impaired endothelium-dependent vasodilation of coronary resistance vessels in hypercholesterolemic patients

To determine the relationship between hypercholesterolemia and the endothelial function of coronary resistance vessels, we studied the changes in coronary blood flow (CBF) in response to acetylcholine, an endothelium-dependent vasodilator, and adenosine, an endothelium-independent vasodilator, in patients with hypercholesterolemia (n = 17) and in control patients (n = 17). All patients had normal epicardial coronary arteries. Serial 2-min infusions of acetylcholine, at 3 micrograms/min and 30 micrograms/min, caused a dose-dependent increase in CBF in each group. The acetylcholine-induced maximal increases in CBF were inversely correlated with the serum cholesterol level (r = -0.55, p < 0.01), and were significantly smaller in the hypercholesterolemic patients than in control patients. However, the adenosine-induced increases in CBF were similar in the two groups. These results suggest that the endothelium-dependent vasodilation of resistance vessels is lessened in patients with hypercholesterolemia even before the formation of atherosclerotic stenotic lesions in epicardial coronary arteries, and that hypercholesterolemia impairs endothelium-dependent vasodilation of coronary resistance vessels.

Analysis of the core region of HCV genome isolated from patients with chronic hepatitis C during intervals of normal ALT concentration

We determined the core region nucleotide and amino acid sequences in specimens from two patients with chronic hepatitis C during intervals of normal and elevated alanine aminotransferase (ALT) concentrations. When the ALT concentrations remained normal, the serum HCR-RNA concentration exceeded that before therapy and most of the clones that could be sequenced had a deletion or an amber mutation. The clones isolated from a HLA B44-positive patient had a mutation at amino acid 91. These results suggest that expression of the wild-type HCV core region genome may be associated with liver cell damage.

Coronary segmental responses to acetylcholine in patients with hypercholesterolemia

We investigated coronary segmental response to intracoronary acetylcholine (ACh) in 19 patients with hypercholesterolemia and 18 patients with normal cholesterol levels. All patients had atypical and chest pain and angiographically normal coronary arteries. After baseline angiography, ACh (3 and 30 micrograms/min) was infused into the left coronary artery, followed by infusion of nitroglycerin. Percent changes in diameter of the proximal, middle, and distal segments of the left coronary arteries were measured by quantitative angiography. In the normocholesterolemic group, 3 micrograms/min of ACh produced significant coronary vasodilation in the distal segments (+8.2 +/- 2.6%, p < 0.005), while 30 micrograms/min did not cause any changes. In the hypercholesterolemic group, 30 micrograms/min of ACh caused significant coronary vasoconstriction in the middle and distal segments (-7.2 +/- 1.9% and -6.2 +/- 1.9%, p < 0.001 and p < 0.01, respectively), while 3 micrograms/min caused no changes. In each group, vasodilator responses to nitroglycerin in the middle and distal segments were significantly greater than those in the proximal segments (p < 0.001). Our results suggest that impaired endothelial function may be evaluated more effectively in the distal coronary segments in patients in the early stage of epicardial coronary atherosclerosis attributable to hypercholesterolemia.

New method for assaying free and total cholesterol in cultured cells by high-pressure liquid chromatography

We developed a simple, sensitive and accurate method for assaying cellular free and total cholesterol by monitoring 4-cholesten-3-one, a conversion product of the cholesterol oxidase-catalyzed oxidation of the free cholesterol that has a strong chromophoric alpha, beta-unsaturated ketone at 240 nm, using a high-pressure liquid chromatographic system. This method measured picomole quantities of free and total cholesterol and precisely determined their concentrations in cells (10(4) range) in culture using 7 beta-hydroxycholesterol as an internal standard.

Partial characterization of regulation of biliary lecithin hydrophobicity: association with organic anion-induced solute cholestasis in rats

We examined the effects of the depletion of bile salts and of the intravenous infusion of sodium taurocholate (STC) with or without bromosulphophthalein (BSP) in rats on the biliary secretion of lipids to clarify the regulatory mechanism(s). Each rat was equipped with a bile-duct cannula to collect bile. After the endogenous bile salt pool was depleted, STC was infused at a constant rate (160 nmol/min per 100 g body wt.) with or without BSP (50, 100, or 150 nmol/min per 100 g body wt.). BSP reduced the biliary secretion of cholesterol and phospholipids dose-dependently without affecting the secretion of bile salts (uncoupling phenomenon). Compared with the physiological and STC-infused condition, the biliary cholesterol/phospholipid ratio and saturated/unsaturated fatty acid ratio increased under the bile salts depletion and uncoupling phenomenon. Data indicate that the hydrophobicity of biliary lecithin increases with a decrease in the bile salt micelle capacity to induce biliary lipid secretion, resulting in a higher packing density of biliary vesicle. The cholesterol-holding capacity of the biliary vesicle is therefore enhanced during the depletion of bile salts and the uncoupling phenomenon.

Repeated piezoelectric lithotripsy for gallstones with and without ursodeoxycholic acid dissolution: a multicenter study

The use of bile acid dissolution therapy in extracorporeal shockwave lithotripsy of gallstones, remains controversial. Our study examined whether chemolitholysis after sufficient disintegration enhanced stone clearance within 6 months of the first lithotripsy. A total of 143 patients who developed one to three radiolucent stones measuring < or = 30 mm in diameter were randomly separated into two treatment groups: 47% were given lithotripsy alone, and 53% lithotripsy plus ursodeoxycholic acid (UDCA). Repeated piezoelectric lithotripsy was given, with no limit on the total number of treatment sessions, to pulverize or disintegrate stones into fragments < 3 mm. Stones were disintegrated in 97% of all patients, and the fragments were < or = 2 mm in 50% of these patients. According to an intention-to-treat analysis, 52% in the lithotripsy alone group and 58% in the UDCA group were free of stones 6 months after the first lithotripsy (P = 0.61). Of the patients with fragments < or = 2 mm, 71% in the former and 86% in the latter group were free of stones 6 months after the first lithotripsy, with no significant difference between the groups. Biliary pain occurred in 25% of all patients, including 3 with acute cholecystitis. We concluded that the sufficient disintegration of gallstones achieved with repeated lithotripsy enhanced the early clearance of fragments, regardless of whether chemolitholysis was employed.

Endoscopic treatment of submucosal invasive colorectal carcinoma with special reference to risk factors for lymph node metastasis

A clinicopathological analysis of the risk factors for lymph node metastasis was performed in 177 patients with submucosal invasive colorectal carcinoma (CRC). The submucosal deepest invasive portion was histologically subclassified as well (W), moderately (M), or poorly (Por) differentiated. M type was further subdivided into moderately-well (Mw) and moderately-poorly (Mp) differentiated. The pattern of tumor growth was classified as polypoid growth (PG) and non-polypoid growth (NPG). Lymph node metastasis was detected in 21 (12%) of the 177 patients. Macroscopically, type IIc and IIa + IIc lesions showed a significantly higher incidence of lymph node metastasis (44% and 30%) than type IIa and I (4% and 8%). Regarding the histologic subclassification, Por and Mp lesions showed a significantly higher incidence of lymph node metastasis (67% and 37%) than W and Mw lesions (4% and 14%). NPG tumors showed a significantly higher incidence of lymph node metastasis (29%) than PG tumors (7%). The depth of submucosal invasion and lymphatic invasion (ly) were also significantly correlated with the incidence of lymph node metastasis (submucosal scanty (sm-s) invasion 4%, massive invasion 20%; ly(+) 23%, ly(-) 5%). None of the lesions with both sm-s invasion and of W or Mw type showed lymph node metastasis. These results indicate that submucosal invasive CRC with both sm-s invasion and of W or Mw type, which shows no ly, is the appropriate indication for endoscopic curative treatment.

Dietary salt decreases cytosolic calcium in platelets from Dahl salt-sensitive rats

To determine whether abnormal cellular Ca2+ handling is involved in salt-induced hypertension of Dahl salt-sensitive rats (DS), we investigated Ca2+ handling in fura 2-loaded platelets of DS and Dahl salt-resistant rats (DR) fed a high-NaCl (8%) or a low-NacL (0.3%) diet for 4 wk from 5 wk of age. At 5 wk of age, blood pressure, resting cytosolic Ca2+ concentration ([Ca2+]i), the thrombin-evoked increase in [Ca2+]i and the size of internal Ca2+ stores of DS were comparable with those of DR. After 4 wk on the diets, resting [Ca2+]i of DS on high-NaCl diet was lower than that of DS on low-NaCl diet, and there was no effect of high salt intake on resting [Ca2+]i in DR. In DS, high salt intake attenuated the [Ca2+]i response to thrombin in the presence of external Ca2+. In contrast, the [Ca2+]i response to thrombin in the absence of external Ca2+ was enhanced by high salt intake in DS. The size of internal Ca2+ stores was increased by high salt intake in DS but not in DR. These data suggest that it is not obligatory for hypertension to be accompanied by an increase in platelet [Ca2+]i.

A new case of apoA-I deficiency showing codon 8 nonsense mutation of the apoA-I gene without evidence of coronary heart disease

We report a 39-year-old Japanese man with HDL and apoA-I deficiency as well as data from members of his family. Corneal opacity and a stomatocyte were found but not tonsillar hypertrophy, xanthomas, or splenomegaly. His serum HDL cholesterol, apoA-I, apoA-II, and LDL cholesterol levels were t mg/dL, < 3 mg/dL, 6 mg/dL, and 175 mg/dL, respectively. Plasma triglyceride, phospholipid, apoB, apoC-III, and apoE levels were all within normal limits. Lecithin:cholesterol acyltransferase activity was half of normal, while lipoprotein lipase and hepatic triglyceride lipase activities were within normal limits. ApoA-I deficiency was confirmed by combined isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis and by an immunoblotting method. We surveyed the apoA-I gene of the patient and five of his family members by direct sequencing after amplification by polymerase chain reaction and found a codon 8 nonsense mutation (TGG --> TAG, Trp --> stop) in exon 3 of the apoA-I gene. The results of a pedigree analysis by DNA sequencing and restricted fragment length polymorphism (Sty I) were consistent with an autosomal codominant trait. Coronary angiography was performed to evaluate coronary atherosclerosis, but no significant luminal narrowing was detected. An intracoronary ultrasound study showed mild intimal hyperplasia in segment 6. In summary, this is a case of apoA-I deficiency without evidence of coronary heart disease.

High dose of fluvastatin sodium (XU62-320), a new inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, lowers plasma cholesterol levels in homozygous Watanabe-heritable hyperlipidemic rabbits

The effects of fluvastatin sodium (XU62-320), a new type of inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, on plasma cholesterol and triacylglycerol levels were investigated using homozygous Watanabe-heritable hyperlipidemic (WHHL) rabbit, an LDL-receptor-deficient animal which expresses a hepatic LDL receptor activity less than 5% that of control rabbits. Plasma levels of total, VLDL- and LDL-cholesterol were decreased profoundly after oral administration of fluvastatin at a dose of 50 mg/kg per day for 4 weeks. Plasma triacylglycerol levels were not affected by fluvastatin. Hepatic HMG-CoA reductase activity increased by 3-fold and hepatic LDL receptor activity increased by only 3.7-fold, as calculated by Scatchard plot analysis, with fluvastatin administration for 4 weeks, and the hepatic mRNA level for the rabbit LDL receptor was increased by 3-fold. Combined administration of fluvastatin (50 mg/kg per day) and cholestyramine, a bile acid sequestrant resin, at a level of 2% of the diet for 4 weeks more profoundly decreased plasma total, VLDL- and LDL-cholesterol levels with induction of hepatic cholesterol 7 alpha-hydroxylase and no further induction of the hepatic LDL receptor. Plasma triacylglycerol levels were increased by the combination treatment. These results suggest that high dose of fluvastatin sodium is effective in lowering plasma cholesterol levels in homozygous WHHL rabbits through the shared mechanisms involving decrease in production and secretion of cholesterol from the liver and the induction of hepatic LDL receptor. Additional effect of cholestyramine on decrease in plasma cholesterol levels seems to be due to the further decrease in hepatic cholesterol secretion by up-regulation of hepatic cholesterol 7 alpha-hydroxylase.

Opposite effects on cholesterol metabolism and their mechanisms induced by dietary oleic acid and palmitic acid in hamsters

The effects of dietary oleic acid on cholesterol metabolism were investigated and compared with those of palmitic acid in hamsters. Addition of 5% oleic acid to a 0.1% cholesterol-supplemented diet decreased plasma total cholesterol, very low density lipoprotein (VLDL) cholesterol, and low density lipoprotein (LDL) cholesterol, increased hepatic LDL receptor activity, and decreased plasma cholesteryl ester transfer protein (CETP) activity in comparison with 0.1% cholesterol alone. In contrast, addition of 5% palmitic acid to a 0.1% cholesterol-supplemented diet increased total cholesterol and LDL-cholesterol, increased plasma CETP activity, and suppressed hepatic LDL receptor activity to a greater extent than 0.1% cholesterol alone. Neither oleic acid nor palmitic acid altered hepatic microsomal 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase activity, but oleic acid increased hepatic microsomal cholesterol 7 alpha-hydroxylase activity. These results suggest that dietary oleic acid inhibits the increases in total, VLDL-, and LDL-cholesterol induced by dietary cholesterol by preventing both LDL receptor suppression and increased CETP activity, whereas dietary palmitic acid augments the cholesterol-induced increases in total and LDL-cholesterol by both further suppression of LDL receptor activity and further stimulation of CETP activity.

Human pancreatic phospholipase A2 stimulates the growth of human pancreatic cancer cell line

Phospholipase A2 (PLA2) from human pancreas, designated hPLA2-I, functions as a digestive enzyme. Interestingly, the present study demonstrated that the mature form of hPLA2-I stimulated the growth of a human pancreatic cancer cell line MIAPaCa-2, whereas the pro-form was ineffective. PLA2s from Laticauda semifasciata fraction I, Crotalus adamanteus venom, Streptomyces violaceoruber and bee venom, showed no proliferative effect to the growth of MIAPaCa-2. The Scatchard plot analysis revealed that the MIAPaCa-2 cell had a specific binding site for the mature hPLA2-I. The equilibrium binding constant (Kd) and the maximum binding capacity (Bmax) were 2.6 nM and 0.4 fmol/10(6) cells, respectively. These results suggest that the mature hPLA2-I, but not the pro-form, may function as a growth factor of pancreas carcinoma via the specific binding site.

Famotidine, a histamine-2-receptor antagonist, inhibits the increase in rat gastric H+/K(+)-ATPase mRNA induced by intravenous infusion of gastrin 17 and histamine

We examined the effects of gastrin and histamine on rat gastric H+/K(+)-ATPase, the enzyme responsible for H+ secretion, gene expression in vivo. Gastrin 17 (G 17) or histamine dihydrochloride (histamine) was continuously infused through the femoral vein of anesthetized rats. Gastric H+/K(+)-ATPase mRNA levels were measured using northern blot analysis. Infusion of G 17 and histamine increased the H+/K(+)-ATPase mRNA level significantly compared with basal control level or vehicle control level (P < 0.01). However, pretreatment with famotidine, a potent histamine-2 (H2)-receptor antagonist, inhibited the increase of rat gastric H+/K(+)-ATPase mRNA following G 17 and histamine infusion. These findings indicate that both histamine and G 17 increase expression of H+/K(+)-ATPase mRNA by activating H2 receptor on the parietal cell.

The relationship between gastric secretion and type of early gastric carcinoma

To determine the relationship between gastric secretion and gastric carcinoma, we investigated gastric acid secretion and the fasting serum levels of pepsinogen I and gastrin in 50 Japanese patients with early gastric carcinoma. After the histological and macroscopic type of carcinoma had been determined, results were compared with findings in 50 Japanese control subjects whose gastric mucosa was endoscopically normal. The maximum gastric acid secretion and fasting levels of serum pepsinogen I were significantly lower in intestinal type gastric carcinoma than in diffuse type carcinoma and in the controls. They were also significantly lower in the non-ulcerative (elevated or flat) type than in the ulcerative (depressed) type of carcinoma. The serum gastrin levels in patients with early gastric carcinoma of either the intestinal or diffuse type were higher than those in the control subjects, though the difference was not significant. Gastric acid secretion and serum pepsinogen I levels were related with both the histological and macroscopic types of gastric carcinoma. These findings suggest that the serum pepsinogen I level might be useful as a maker for early gastric carcinoma of the intestinal type.

Effect of the transmembrane gradient of magnesium and sodium on the regulation of cytosolic free magnesium concentration in human platelets

1. To clarify the mechanism by which cytosolic free Mg2+ concentrations ([Mg2+]i) are regulated in human platelets, we investigated platelet membrane permeability to Mg2+ by altering extracellular Mg2+ concentrations, and tested the existence of a Na(+)-Mg2+ exchanger by manipulating the transmembrane Na+ gradient. 2. Platelet [Mg2+]i was 421 +/- 52 mumol/l in healthy men. [Mg2+]i remained constant during a 120 min exposure to nominally zero (low) or 5 mmol/l (high) external Mg2+ concentrations. 3. Preincubation of platelets with 10(-4) mol/l ouabain effectively decreased the transmembrane Na+ gradient. The ouabain-induced increase in [Mg2+]i was statistically significant after 30 min of exposure (14.6 +/- 2.0%) and reached 24.6 +/- 4.5% after 60 min. Similarly, the replacement of extracellular Na+ with N-methyl-D-glucamine significantly increased [Mg2+]i by 48.5 +/- 3.9% and 78.8 +/- 12.5%, respectively. 4. These results suggest that [Mg2+]i is well controlled in the presence of large transmembrane Mg2+ concentration gradients, and a Na(+)-Mg2+ exchanger may be involved in the regulation of [Mg2+]i in human platelets.