Metabolic actions of insulin-like growth factor I in cultured glomerular mesangial cells

Glomerular mesangial cells in culture have been reported to possess a considerable number of receptors specific to insulin-like growth factor I (IGF-I), with very small number of receptors specific to insulin. To explore acute metabolic effects of IGF-I on mesangial cells, uptake of glucose and amino acid was measured in the presence of IGF-I or insulin. IGF-I stimulated D-[U-14C]glucose incorporation, 2-deoxy[1-3H]glucose uptake and alpha-[methyl-3H]aminoisobutyric acid (AIB) uptake into cultured mesangial cells by 139.8% +/- 2.1%, 116.6% +/- 1.7%, and 214.9% +/- 12.8% (percent of basal), respectively. Similar maximal stimulation was also induced by insulin, while the ED50 of IGF-I to stimulate these uptake systems (9.98 +/- 2.36, 3.45 +/- 1.86, and 3.35 +/- 0.40 ng/mL, respectively) was significantly lower than that of insulin (120.8 +/- 28.5, 61.8 +/- 7.7, and 76.3 +/- 17.5, respectively). These results indicate that, in cultured glomerular mesangial cells, IGF-I induces acute metabolic effects, possibly through its own receptors.

Reduced activity of renal angiotensin-converting enzyme in streptozotocin-induced diabetic rats

To clarify the possible role of intrarenal renin-angiotensin system (RAS) in the evolution of renal hemodynamic alteration in diabetes, we investigated the change of tissue angiotensin-converting enzyme (ACE) activity, a key enzyme of RAS, in the kidneys obtained from streptozotocin-induced diabetic rats. Tissue ACE activity was significantly reduced in both outer cortex (0.29 +/- 0.04, mean +/- SEM, n = 6) and inner cortex with outer medulla (2.43 +/- 0.28, n = 6) of the kidneys from diabetic rats 2 weeks after induction of diabetes compared with those from control rats (0.47 +/- 0.05, n = 7, in outer cortex; 3.68 +/- 0.32, n = 7, in inner cortex with outer medulla). ACE activities in the lung and aorta of diabetic rats were not different from those of control rats. ACE activities in the serum and urine were significantly elevated in diabetic rats. Treatment of diabetic rats with insulin to achieve near euglycemia completely prevented these alterations in ACE activity, except that, in the urine, the elevation of ACE was partially corrected with insulin. In contrast to ACE activity, activity of N-acetyl-beta-D-glucosaminidase (a lysosomal enzyme of the tubule) and r-glutamyl transpeptidase (a brush border enzyme) in the kidney were not reduced in diabetic rats, whereas in the urine both enzyme activities were significantly elevated in diabetic rats. It is likely, therefore, that the reduction of ACE activity in the kidneys of diabetic rats may reflect the impairment of vascular endothelial cells in the kidney, rather than tubular damage.(ABSTRACT TRUNCATED AT 250 WORDS)

Dual mechanism of angiotensin II inhibits ANP-induced mesangial cGMP accumulation

To evaluate an interaction between vasoconstrictive (Ang II) and vasodilating (ANP) peptides, we examined the effect of Ang II on ANP-induced accumulation of cGMP in cultured glomerular mesangial cells. ANP rapidly increased intracellular cGMP levels, with a peak stimulation at one minute in the absence of IBMX and at ten minutes in the presence of IBMX. The ANP-induced cGMP accumulation was significantly inhibited when the cells were treated with Ang II simultaneously with ANP for one minute in the absence of IBMX. This inhibitory effect of Ang II was completely abolished by IBMX and significantly reduced in calcium-free media or by W7, but not affected by H7. Similar inhibitory effect was observed when cells were treated with A23187 but not with TPA for one minute. In the presence of IBMX, Ang II inhibited ANP-induced cGMP accumulation when cells were treated with Ang II for 15 minutes prior to the stimulation by ANP. This inhibition by Ang II was blocked by H7. ANP-induced increase in particulate guanylate cyclase activity was significantly reduced in the cells treated with Ang II or TPA. This reduction of enzyme activity was also prevented by H7. These results indicate that Ang II inhibits ANP-induced cGMP accumulation in cultured glomerular mesangial cells through at least two mechanisms; one is the activation of calcium-dependent, calmodulin-stimulated cyclic nucleotide phosphodiesterase in the initial phase, and the other is the inhibition of guanylate cyclase resulting from protein kinase C activation in the maintenance phase.

Role of sympathetic activity in blood pressure reduction with low calorie regimen

To investigate the effects of a low calorie regimen on sympathetic function and its relation to blood pressure response, 22 untreated obese essential hypertensive patients (50 +/- 2 years, body mass index 29 +/- 1 kg/m2) were hospitalized and a diet was prescribed of 2,000 kcal/day for 5 days (control period) followed by 800 kcal/day for 21 days without changing salt intake (8-10 g/day). The dose of intravenous phenylephrine infusion needed to elevate systolic blood pressure 20 mm Hg (CD20) and the 24-hour urinary excretion of norepinephrine (UNE) were measured. During the low calorie period, blood pressure normalized in 14 patients (responder group, 124 +/- 3/79 +/- 4 mm Hg) and eight remained hypertensive (poor responder group, 158 +/- 6/103 +/- 3 mm Hg). At the control period, blood pressure and body mass index were similar, but the responder group had higher UNE (134 +/- 15 micrograms/day) and CD20 (127 +/- 11 micrograms) than the poor responder group (89 +/- 6 micrograms/day and 79 +/- 13 micrograms, respectively). During the low calorie period, both UNE (87 +/- 15 micrograms/day) and CD20 (74 +/- 10 micrograms) decreased in the responder group; no change was seen in the poor responder group. Changes in UNE and systolic blood pressure were correlated (r = 0.6, p less than 0.05). In conclusion, suppression of sympathetic activity plays a role in blood pressure reduction during moderate caloric restriction.

Glucose-induced overproduction of type IV collagen in cultured glomerular mesangial cells

Type IV collagen production by cultured rat glomerular mesangial cells was evaluated quantitatively by measuring type IV collagen secreted into culture media and associated with the cells using enzyme-linked immunosorbent assay (ELISA). The majority of type IV collagen was secreted into culture media; type IV collagen increased with cell growth in the early log phase and decreased in the late log phase and after cofluency. By exposing the cells to high concentrations of glucose (27.8 mM), both secreted and cell-associated type IV collagens increased significantly compared with the cells cultured under normal glucose concentrations (5.6 mM) or under equivalent concentrations of mannitol, resulting in a significant increase in total type IV collagen accumulation.

Insulin-like growth factor I (IGF-I) stimulates glucose and amino acid uptake in cultured glomerular mesangial cells

Cultured mesangial cells possess a large number of receptors specific to IGF-I with a small number of insulin receptors. Physiological concentrations of IGF-I increased the uptakes of aminoisobutyric acid and 2-deoxyglucose in mesangial cells, while insulin exhibited similar effects only with unphysiologically high concentration. These findings suggest that, in cultured mesangial cells, IGF-I may regulate cellular metabolic functions such as glucose and amino acid uptakes through its own receptors rather than insulin receptors.

Glucose enhances type IV collagen production in cultured rat glomerular mesangial cells

Type IV collagen production by cultured glomerular mesangial cells and the effect of glucose on it were evaluated in order to explore the possible contribution of mesangial cells to the accumulation of type IV collagen in mesangial matrix typically seen in diabetes. Type IV collagen was measured quantitatively by enzyme-linked immuno-sorbent assay. The majority of type IV collagen was secreted into culture media and secreted-type IV collagen increased with cell growth in early log phase and decreased in late log phase and after confluency. By exposing the cells to high concentrations of glucose (27.8 mmol/l), both secreted- and cell-associated-type IV collagens increased significantly compared with the cells cultured under normal glucose concentrations (5.6 mmol/l) or under equivalent concentrations of mannitol, resulting in a significant increase in total type IV collagen accumulation from 32.1 +/- 6.4 (under 5.6 mmol/l glucose) to 51.0 +/- 4.6 micrograms/dish (mean +/- SD, n = 4) on day 4, from 113.6 +/- 6.6 to 156.8 +/- 7.1 on day 6, from 248.5 +/- 15.2 to 310.0 +/- 12.6 on day 8 and from 372.4 +/- 14.8 to 507.9 +/- 17.2 on day 12. These results indicate the importance of glucose-induced alteration of mesangial cell function in the development of diabetic mesangial expansion.

Specific DNA probe for the detection of Theileria sergenti infection in cattle

A simple procedure was developed for detection of Theileria sergenti infection on the basis of hybridization of parasite DNA with a specific probe. A genomic DNA library of T. sergenti constructed in pUC-18 was screened to detect clones containing the parasite's DNA sequences by colony and Southern hybridizations. Two positive DNA inserts were purified from the recombinant plasmids and used as probes labelled with 32P or non-isotopic reagent, biotin-11-dUTP. 32P-radiolabelled and non-radioactive probes appear to be sensitive enough to detect 15 pg (equivalent to 1,200 parasites) and 125 pg (equivalent to 10,000 parasites) of purified T. sergenti DNA, and in diluted T. sergenti-infected red blood cells, they are able to detect 8,000 parasites and 16,000 parasites, respectively.

[Smoldering leukemia with pyoderma gangrenosum]

A 76-year-old male admitted to Surugadai Nihon University hospital complaining of general fatigue, slight fever and anorexia. The laboratory examination revealed anemia and an appearance of a few myeloblasts and 7% of monocytes in the peripheral blood. The nucleated cell count was 2 x 10(4)/microliters with 43% myeloblasts in the bone marrow aspirate. He was diagnosed as acute myelomonocytic leukemia. He did not receive any chemotherapy for leukemia because of his old age and smoldering disease. Pyoderma gangrenosum developed in the left submandibular and axillary regions about 6 months later. Three more month later, significant increase of myeloblast was recognized in the peripheral blood and the bone marrow. It has been reported that pyoderma gangrenosum precedes a remarkable increase of leukemic cells in the patients with acute leukemia in complete remission and with myelodysplastic syndrome. In our case, to, the same process was strongly suggested.

[Role of the serotonergic nervous system in hemodynamic and vasopressin responses to centrally administrated angiotensin-II in spontaneously hypertensive rats]

The purpose of the study is to investigate the role of the serotonergic nervous system in centrally administrated angiotensin II (A-II) mediated hemodynamic as well as vasopressin (AVP) responses. Eight-week-old male SHR and age-matched Wistar Kyoto rats (WKY) were used and the experiment was performed in the conscious state. In protocol 1, after resting observation of 30 minutes 10ng of A-II was given intracerebroventricularly (i.c.v.). This was followed by i.c.v. injection of 1 microgram of 5-HT2 receptor antagonist, xylamidine, 50 minutes later; then 10ng of i.c.v. A-II was repeated after 10 minutes (SHR: n = 7, WKY: n = 10). In protocol 2, plasma vasopressin (AVP) was measured in the following groups. In one group, 1.3ml of blood was sampled from the carotid cannula after resting observation, and the same amount of blood from an age-matched donor rat of the same strain was transfused immediately. Two hours later, 10ng of A-II was given i.c.v., and blood was sampled again after 1 minute (SHR: n = 7, WKY: n = 12). In another group, 1 microgram of xylamidine was given i.c.v. and was followed by 10ng of A-II 10 minutes later; then blood was collected after 1 minute (SHR: n = 8, WKY: n = 13). In protocol 1, resting MAP were 144 +/- 6mmHg in SHR and 99 +/- 2mmHg in WKY. I.c.v. A-II elicited a consistent pressor response in both SHR and WKY, but the response was significantly larger in SHR than that in WKY, +45 +/- 3 and +37 +/- 1mmHg, respectively. Xylamidine had no effect on MAP, and repeated A-II produced significant pressor responses. However, the responses were significantly smaller in both SHR (+36 +/- 3mmHg) and WKY (+25 +/- 1mmHg) as compared with those to initial A-II injection. In protocol 2, resting AVP were similar in SHR (1.5 +/- 0.2pg/ml) and in WKY (1.6 +/- 0.1pg/ml). However, after i.c.v. A-II injection, AVP became higher in SHR (131 +/- 14pg/ml) than in WKY (64 +/- 6pg/ml). AVP after A-II injection with xylamidine pretreatment were similar in SHR (48 +/- 6pg/ml) and in WKY (45 +/- 4pg/ml). Since the responses of both MAP and AVP to i.c.v. A-II were larger in SHR, and the responses were effectively suppressed by S2 receptor antagonists, the central serotonergic nervous system may play an important role in the hemodynamic as well as AVP responses to i.c.v. A-II administration.

Clinical application of echocardiographic imaging to diagnosis of coronary artery disease

Ergometer two-dimensional echocardiography was performed in 28 subjects complaining of chest pain but without myocardial infarction. Sequential ergometer loading was initiated at 50 or 75 watts, and increased in several stages. Apical four-chamber view two-dimensional echocardiograms were recorded onto video tape, and video images were converted into digital computer signals. After cine-loop display, computer image processing included noise reduction and edge enhancement, M-mode measurements were made at a designated level on the two-dimensional echo images. Wall motion was also analyzed directly from the two-dimensional echo images, using an auto-edge detection method. The derived data were compared with results from coronary angiograms. No echo abnormality was observed at rest, whereas during exercise wall motion was depressed at the diseased site of the angiogram; the amplitude of excursion and the changes in systolic and diastolic velocity were disturbed at the septum in LAD-involved patients, and in the posterolateral wall in both Cx and RCA patients. The imaging success rate using the computer-aided analysis was found to be 92.9%. Sensitivity for diagnosis of coronary artery disease was 82.1% and specificity 89.3%. Ergometer two-dimensional echocardiography with assisted computer image processing appears to be one of the most valuable tools for clinical real time evaluation of coronary artery disease.

[A double-blind comparative study of intracoronary administration of GE-0943 and urokinase: multicenter study]

Coronary thrombolysis with plasminogen proactivator, GE-0943, was undertaken in patients with acute myocardial infarction and compared with urokinase. Fifty patients were given 6000 units of GE-0943 intracoronary and the totally occluded infarct-related arteries were recanalized in 92.0%. Fifty-four patients who were given 3000 units of GE-0943 intracoronary demonstrated a recanalization rate of 68.2%, while intracoronary administration of urokinase in 54 patients showed a recanalization rate of 70.4%. There was only one patient with hemorrhagic complication among GE-0943 3000-units group, none among GE-0943 6000-units group, and 5 among urokinase group. Thus, intracoronary administration of GE-0943 is very effective and safe with a dose up to 6000 units.

[The effects of the intracerebroventricular administration of cimetidine on hemodynamics in conscious rats: relation to the sympathetic nervous system]

Histamine H2-receptor antagonists administered into the central nervous system have been shown to increase arterial pressure (AP) in anaesthetized animals (Paakkari et al., 1982). Few studies have been reported on the effects of centrally administered cimetidine (CIM), one of the histamine H2-receptor antagonists, in conscious animals. However, the mechanism of the pressor action of histamine H2-receptor antagonists remains unclear. The present study was designed to investigate the hemodynamic effects of intracerebroventricular (i.c.v.) CIM and the interaction between the sympathetic nervous system and histamine receptor system in conscious rats. Male Wistar rats weighing 200 gr were prepared for the experiment under a conscious and minimally restricted state. Five micrograms of i.c.v. saline (SAL-ICV group, n = 5) did not produce significant changes in mean arterial pressure (MAP) or heart rate (HR) (MAP from 85.6 +/- 3.4 to 86.0 +/- 4.3 mmHg and HR from 395.0 +/- 13.9 to 395.2 +/- 8.2 bpm, respectively). Twenty micrograms of i.c.v. phenoxybenzamine (POB-ICV group, n = 6) decreased MAP from 95.8 +/- 4.1 to 85.2 +/- 3.1 mmHg, -10.7 +/- 2.2 mmHg as delta MAP, and increased HR from 392.5 +/- 8.5 to 435.3 +/- 13.9 bpm, +42.8 +/- 6.8 bpm as delta HR. Two-hundred micrograms of intravenous (i.v.) POB (POB-IV group, n = 5) also decreased MAP from 96.0 +/- 4.3 to 71.0 +/- 5.1 mmHg, -25.0 +/- 2.7 mmHg as delta MAP, and increased HR from 395.8 +/- 10.5 to 473.0 +/- 12.4 bpm, +77.2 +/- 7.6 bpm as delta HR. The changes in MAP and HR were much greater in the POB-IV group than those in the other two groups. The subsequent i.c.v. administration of 250 micrograms of CIM induced an increase in MAP (+19.4 +/- 1.7 mmHg as delta MAP) and a decrease in HR (-36.4 +/- 3.1 bpm as delta HR) in the SAL-ICV group, which continued for at least 30 minutes producing peak effects 2 minutes after i.c.v. administration of CIM. However, an elevation of MAP caused by i.c.v. CIM was much more inhibited in the POB-ICV group than in the POB-IV group (+2.5 +/- 0.7 mmHg as delta MAP in the POB-ICV group and +5.0 +/- 1.3 mmHg as delta MAP in the POB-IV group, respectively).(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of chronic atenolol therapy on cardiovascular response to isometric exercise in essential hypertension

Cardiovascular response to 2 min of isometric handgrip exercise at 50% of maximum voluntary contraction was studied echocardiographically in 10 essential hypertensives, before and during treatment with atenolol for a mean of 2 months. The patients responded with increases in heart rate, systolic and diastolic blood pressures, cardiac output and calculated triple product, no changes in stroke volume and total peripheral resistance, and decreases in ejection fraction, mean velocity of circumferential shortening and mean diastolic posterior wall velocity of the left ventricle before treatment. Chronic atenolol therapy attenuated the increases in heart rate, blood pressure and triple product, and the decreases in ejection fraction, mean velocity of circumferential shortening and mean diastolic posterior wall velocity of the left ventricle but resulted in a marked increase in total peripheral resistance. The pressure response and triple product rise in response to isometric handgrip exercise were also decreased. This suggests an obvious advantage to hypertensive patients who may, therefore, be protected from the risk of cardiovascular complications following isometric exercise.

[The significance of early coronary reperfusion in patients with acute myocardial infarction assessed by regional wall motion]

Left ventricular ejection fraction, regional wall motion, hospital mortality rate, and reocclusion rate of the infarct-related coronary artery after thrombolytic therapy were examined in 164 consecutive patients who were admitted within 12 hours of the onsets of their symptoms of acute myocardial infarction. The patients were divided into three groups based on the findings of initial coronary angiography before and after administration of urokinase: (1) stenosed (the infarct-related coronary blood flow was visualized at initial angiography) (n = 41); (2) successfully thrombolysed (n = 82); and (3) unsuccessful (n = 41). The patients in each group were also subdivided into three subgroups based on the recanalized time (hours): within three, three to six hours and six hours or longer. The hospital mortality rates were 4.9% (two of the 41 patients) in the stenosed; 8.5% (seven of the 82 patients) in the thrombolysed; 29.3% (12 of the 41 patients) in the unsuccessful group, and 12.8% (21 of the 164 patients) overall, respectively. There were significant differences among these three groups. The incidence of pump failure as a cause of death in the acute stage was significantly low in the stenosed (two of the 41 patients) and in the thrombolysed (3 of the 82 patients) groups compared to the unsuccessful group (eight of the 41 patients). The rates of rethrombosis one month after thrombolytic treatment were 3% in the stenosed and 4% in the thrombolysed groups. On the contrary, visualization of coronary blood flow at the chronic stage (approximately one month later) was confirmed in 19% of the patients in the unsuccessful group. Left ventricular ejection fraction one month after thrombolytic therapy in the subgroup with the recanalized coronary arteries within three hours was significantly higher than that of the unsuccessful group, but, after three hours of procedure, no significant difference of left ventricular ejection fraction was present among three groups. Regional wall motion in patients with the recanalized coronary artery within 12 hours was better than that of the unsuccessful group. The area of improved wall motion was wide in patients with early recanalization in the stenosed and thrombolysed groups. Thus, early recanalization within three hours is mandatory for reducing mortality and for improving ejection fraction and wall motion.

Randomized, double-blinded multicenter study. Comparison of intracoronary single-chain urokinase-type plasminogen activator, pro-urokinase (GE-0943), and intracoronary urokinase in patients with acute myocardial infarction

Coronary recanalization rates and changes in the coagulation and fibrinolysis system were evaluated in a randomized fashion in patients with acute myocardial infarction after intracoronary administration of single-chain urokinase-type plasminogen activator (pro-urokinase: GE-0943) or urokinase. Three groups of patients were studied: group H (n = 50), 6,000 units pro-urokinase i.c.; group L (n = 44), 3,000 units pro-urokinase i.c.; and group U (n = 54), 960,000 IU urokinase i.c. Coronary recanalization rates determined angiographically after 45 minutes of intracoronary infusion averaged 90% in group H, 59% in group L, and 61% in group U. The differences were statistically significant between group H and the latter two groups. Pro-urokinase affected plasma proteins of the fibrinolytic system to a lesser degree than urokinase. Bleeding complications were present in one patient in group L, in none in group H, and in five in group U. Thus, intracoronary administration of 6,000 units pro-urokinase is more effective in coronary thrombolysis and causes less systemic fibrinogenolysis than intracoronary administration of urokinase.

Effects of low protein intake on protein metabolism of Papua New Guinea highlanders studied with [15N]glycine

The effects of low protein intake on protein metabolism, including the size of pools and the protein synthesis rates, were studied by use of [15N]glycine in Papua New Guinea highlanders. Studies were made on 9 men between October and December in 1982. In experiment 1, two subjects were given a protein-free diet (PFD) containing 49.1 kcal/kg of energy. In experiment 2, subjects were given a sweet-potato diet (SPD) containing 45.4 kcal/kg of energy and 0.507 g/kg of protein for 8 days, and then were given a low-protein sweet-potato diet (LPSPD) containing 50.0 kcal/kg of energy and 0.265 g/kg of protein. During the SPD period, the sizes of the metabolic and active protein pools (mean +/- SD) were 270 +/- 134 mgN/kg and 362 +/- 107 mgN/kg, respectively, and the rates of active and inactive protein synthesis were 463 +/- 161 mgN/kg/day and 299 +/- 38 mgN/kg/day, respectively. During the LPSPD period, the sizes of the metabolic pool and active protein pool were 131 +/- 64 mgN/kg and 378 +/- 106 mgN/kg, respectively, and the rates of active and inactive protein synthesis were 490 +/- 206 mgN/kg/day and 280 +/- 26 mgN/kg/day, respectively. The protein metabolism in the LPSPD showed no significant difference from the SPD. The results suggest that, when the energy levels were approximately the same, protein metabolism in Papua New Guinea highlanders was maintained in spite of the decrease in protein intake.

Experimental and clinical investigations for the time interval from onset of symptoms to the coronary reperfusion

To clarify the relationship between time interval from the onset of coronary occlusion to the reperfusion and reperfusion rates or left ventricular function, an experiment with 113 mongrel dogs was carried out. Coronary thrombi experimentally induced within 4 hours in 63 dogs were rapidly lysed by intracoronary thrombolytic agent (Experiment 1). Infarct size was investigated in 17 dogs. The infarct size (% of left ventricle) in 9 dogs with 4-hour reperfusion following 2-hour coronary occlusion was significantly smaller than that in 8 dogs with 6-hour occlusion (12.0 +/- 7.9 vs 19.1 +/- 8.7% respectively p less than 0.05) (Experiment 2). The infarct size in 8 dogs with 7-day reperfusion following 2-hour occlusion was also significantly reduced compared to that in 7 dogs with 7-day occlusion (16.3 +/- 7.4 vs 28.5 +/- 8.9%, respectively p less than 0.02) (Experiment 3). The infarct size in 11 dogs with 4-hour reperfusion with verapamil administration following 2-hour occlusion was significantly reduced compared to that in 7 dogs with 6-hour occlusion without verapamil (5.5 +/- 1.9 vs 20.3 +/- 3.3%, respectively p less than 0.01) (Experiment 4). In experiment 3, anterior wall motion also was assessed by contrast ventriculography and infarct related areas in reperfused group was found to be improved compared to non-reperfused group at 7 days after infarction. In clinical studies, 121 patients who were admitted within 12 hour of onset of symptoms, were investigated to evaluate reperfusion rates and left ventricular function. The reperfusion rate of young age thrombus within 3 hours was 89% of 18 patients with completely occluded coronary artery. It was 77% of the 52 patients with 3 to 6 hour occlusion and 72% of the 18 patients with over 6 hour occlusion. There was a tendency towards high reperfusion rates in younger thrombus. In patients who were recanalized within 3 hours from the onset of symptoms ejection fraction of left ventricle at the chronic stage had a significantly higher percentage when compared to the unsuccessful group. Wall motion of infarct-related areas in patients who were thrombolysed within 6 hours was improved compared to the unsuccessful group. Administration of verapamil during reperfusion in patients with acute myocardial infarction suppressed rapid CK release and sigma CK. Thus, young age thrombus can be lysed easily, earlier recanalization after coronary occlusion can reduce infarct size and improve left ventricular function. Reinforced administration of verapamil during reperfusion can also reduce infarct size.

[Effects of ketanserin on hemodynamic changes after intracerebroventricular corticotropin releasing factor administration in rats]

In order to elucidate the relation between the serotonergic nervous system and the hypothalamus-pituitary system in hemodynamic regulation, the effects of a serotonin S2 receptor antagonist, ketanserin, on hemodynamic changes after intracerebroventricularly (i.c.v.) administrated corticotropin releasing factor (CRF) were investigated. Male Wistar rats (n = 19) weighing approximately 200 g were used. Thirty minutes after either intravenous (i.v.) (KET-IV group) or intracerebroventricular (KET-IC group) administration of 100 micrograms of ketanserin, 10 micrograms of CRF was given i.c.v. and mean arterial pressure (MAP) and heart rate (HR) were observed for 40 minutes, which was followed by blood sampling for plasma norepinephrine (PNE). The experiment was performed under conscious state. Resting MAP and HR were similar in both groups. Neither i.v. or i.c.v. ketanserin alone induced significant changes in MAP and HR. Although there was consistent pressor responses (+10 +/- 1.7 mmHg) and increase in HR (+31 +/- 13 bpm) after CRF administration in KET-IV group, there was not significant changes in MAP (+17 +/- 1.0 mmHg) and HR (+4.3 +/- 5.7 bpm) in KET-IC group. PNE was significantly higher in KET-IV group than that in KET-IC group, 489 +/- 71 pg/ml and 179 +/- 57 pg/ml, respectively. These data suggest that the pressor response to i.c.v. CRF is related to the increased peripheral sympathetic tone, and that the central serotonergic nervous system may play an important role in the hemodynamic changes.

Responses of sodium balance, blood pressure, and other variables to sodium loading in Papua New Guinea highlanders

For determination of the responses of sodium balance, blood pressure, and other relevant variables to Na loading in people with a low intake of Na, 10 male Papua New Guinea highland subjects were given additional Na at two levels (128 and 256 mmol/d) for 10 d after a 3-d control period of low-Na diet. Na loading caused a marked positive balance of Na, decreases of aldosterone concentration and renin activity in the plasma, and a decrease of urinary aldosterone excretion. The blood pressure, particularly that measured at noon, increased in the latter half of the Na-loading period, the increase being significant in the group given 256 mmol of sodium daily: the systolic and diastolic blood pressure increased from 92 +/- 8 over 56 +/- 7 mm Hg in the control period to 102 +/- 7 over 60 +/- 4 mm Hg in the latter half of the test period (p less than 0.05).