Preliminary study on the effects of bar placement on the thorax after the nuss procedure for pectus excavatum using bone scintigraphy

AIM

Bone scintigraphy was performed to elucidate the effects of the Nuss procedure for pectus excavatum on the bony thorax.

METHODS

Eight boys and 6 girls (5 - 24 years of age) underwent bone scintigraphy, using (99m)Tc-HMDP. Eleven patients were studied 5 to 21 days after the Nuss procedure; 6 were studied 20 to 24 months after the operation before bar removal. Three of 14 were studied twice after the Nuss procedure and before bar removal.

RESULTS

In the early postoperative phase, RI accumulation was found at the sternum and ribs in only 1 of 6 patients under 9 years of age, whereas in all 5 older patients, RI had accumulated at the sternum. Scintigrams before bar removal revealed, regardless of age, hot spots at the lateral ribs in contact with the bar and at the costochondral junctions where the bar passed through the intercostal spaces. Furthermore, chest roentgenograms showed the deformed lateral ribs in contact with the bar.

CONCLUSIONS

The Nuss procedure creates minute fractures at the sternum and the ribs, especially in older patients. The bar deforms the ribs and restrains the growth of the thorax. Furthermore, it constantly rubs against the ribs and can therefore cause late complications. Bone scintigraphy may determine the appropriate timing for bar removal.

An evaluation of use of information technology equipment among Japanese elderly women--relation between health status and the preferred input device for the Internet

This study was conducted to determine how mobile phones (MP) and the Internet through personal computers (IPC) have been used among Japanese elderly women. It also aims to examine the relationship between the input devices and factors such as age, health status, and future needs for a MP and the IPC. The magnitude of the relation was evaluated by the odds ratio (OR). The survey was done in December 2000 and January 2001. The study sample was forty women, 78.5 +/- 4.5 years of age (70-89), who lived in their own houses in Y Town near Himeji City, Hyogo, Japan. Findings reveal that use of a MP was 10.0% and none used the IPC. On the other hand, 60.0% of the subjects were interested in using a MP in the future and 27.5% in using the IPC. The touch screen was the most preferred input device among the elderly with high age [OR = 3.86, 95% confidence interval (CI) 0.83-18.98]. It was also preferred by subjects with more difficulties (OR = 5.00, 95% CI 1.05-25.41) and less future need for a MP and the IPC (OR = 7.22, 95% CI 1.34-43.88). On the other hand, the Japanese kana syllabary (JKS) was the most preferred input device among those with a low age (OR = 4.33, 95% CI 0.68-35.00) and with a more future need for a MP and the IPC (OR = 6.33, 95% CI 1.14-39.59). Considering these results, we intend to create a type of keyboard that combines the features of touch screen and JKS for the elderly women.

Expression of cytokines and factors modulating apoptosis by human sinusoidal leucocytes

BACKGROUND/AIMS

Liver sinusoids contain a large population of spontaneously cytotoxic cells (NK cells), CD8+ T cells and macrophages. The physiological role of these leucocytes remains unclear. They may participate in immune surveillance and peripheral tolerance by deleting tumour cells, virus-infected cells and activated T cells as they traffic through the liver. In order to gain further information about the function of these leucocytes within the hepatic sinusoids, we examined their production of immunomodulatory cytokines and apoptosis-related molecules.

METHODS

Semi-quantitative polymerase chain reaction and immunohistochemistry were used to determine the spontaneous production of cytokines and apoptosis-related molecules by sinusoidal leucocytes isolated from donor liver preservation solution.

RESULTS

In comparison with matched peripheral blood mononuclear cells, sinusoidal leucocytes produced more mRNA for IL-10, IL-15, TNF-alpha, IL-18, IFN-gamma, FasL, perforin and granzyme. IL-4 and IL-12 were not detected and IL-2 was only faintly detected in the liver-derived CD4+ population. Less bcl-2 was expressed in liver-derived CD4+ and CD8+ cells in comparison with matched peripheral blood cell populations.

CONCLUSIONS

The cytokines produced spontaneously by sinusoidal leucocytes are consistent with their high level of activation and spontaneous cytotoxicity. Their strong expression of apoptosis-mediating molecules (FasL, perforin, granzyme and TNF-alpha) support a role for these cells in immune surveillance and peripheral tolerance induction.

A transient increase in endogeneous erythropoietin levels after paediatric liver transplantation

We investigated whether liver transplantation affects endogeneous erythropoietin (EPO) synthesis. Serum EPO levels were measured before transplantation and during the peri-transplant period in ten consecutive paediatric patients who had received a liver allograft without recombinant EPO therapy. All patients were anaemic on post-operative day 1 (POD 1); however, the haemoglobin levels of three patients gradually increased and required phlebotomy on POD 5-9. The serum levels of EPO in all patients were within the normal range before surgery, but six of the ten patients had a transient increased level of EPO at 1248 h after transplantation. A transient increase of endogeneous EPO following paediatric liver transplantation may be associated with extramedullary erythropoiesis in human liver grafts.

[The effects of fluid ingestion and its composition on uric acid metabolism during high intensity long term exercise]

The purpose of this study was to analyze the effects of fluid ingestion and its composition on uric acid metabolism after exercise. Six healthy males volunteered for the study which was comprised of three different experiments; Exp. 1, Exp. 2, and Exp. 3. In all the experiments, subjects performed treadmill exercise (70%VO2max) for 70 minutes respectively. For seven hours after exercise, subjects ingested mineral water at 10 degrees C ad-lib in Exp. 1, 1.5 times the volume of mineral water consumed in the first experiment in Exp. 2, and the same volume of sports drink as in the first experiment in Exp. 3. No significant differences were observed in oxygen uptake and heart rate during exercise among the three experiments, so it was considered that the produced serum uric acid (SUA) levels in the three experiments were about the same level. However, the decrease in SUA, urinary uric acid excretion (UUA), clearance of uric acid (CUA) and fractional excretion of uric acid (FEUA) in Exp. 3, in which the sports drink was consumed instead of mineral water were higher than in Exp. 1 and Exp. 2. On the other hand, no significant differences were found in Exp. 2 and Exp. 3. A significant relationship between UUA and FEUA was found among the three experiments, while there was no corrleation between UUA and urine volume. These results show that; 1) the sports drink ingestion can increase the efficiency of recovery from high serum uric acid after exercise, 2) the increase in uric volume due to high mineral water intake does not elevate UUA, and 3) the increase in UUA due to sports drink ingestion was associated with the increase of FEUA.

Modified Kasai's procedure for a choledochal cyst with a very narrow hilar duct

Excision has been widely recognized as the treatment of choice for choledochal cysts. For biliary reconstruction after cyst excision, we have strongly recommended hepaticoenterostomy at the hepatic hilum with a wide anastomotic stoma to prevent postoperative cholangitis. However, we recently treated two infants in whom a wide anastomotic stoma could not be made due to a narrow hilar duct. Therefore, a hepatic portojejunostomy with Roux-en-Y anastomosis (Kasai's procedure) was performed after cyst excision in both case to permit free drainage of bile. The mucosa of the hilar duct was everted and fixed to the liver parenchyma to prevent stricture formation. Both babies have done well since the surgery.

Alveolar rhabdomyosarcoma of the lung in a child

The case of a 22-month-old boy with alveolar rhabdomyosarcoma of the lung is presented. Brain metastasis and recurrence of the right pulmonary hilum and parietal pleura developed 6, 11, and 24 months (respectively) after tumor resection. Chemotherapy and radiotherapy were effective. Neuron-specific enolase was very helpful in detecting metastasis and disease recurrence. Primary pulmonary rhabdomyosarcoma can be divided into two groups: tumor in the normal lung, and tumor in cystic lesions of the lung.

Does hyperamylasemia in choledochal cyst indicate true pancreatitis? An experimental study

Patients with choledochal cyst often have repeated attacks of abdominal pain accompanied by hyperamylasemia, and they may be diagnosed as having acute pancreatitis. However, the attacks generally tend to subside in a short period by conservative treatment, and evidence of pancreatitis is rarely observed at the time of surgery. Choledochal cyst is commonly associated with pancreatobiliary maljunction, and high concentrations of pancreatic enzymes in bile are usually observed. When the bile duct pressure increases due to obstructive cholangitis, pancreatic enzymes in bile may regurgitate into the blood stream. Cholangiovenous reflux of amylase might cause hyperamylasemia. In order to investigate the mechanism of hyperamylasemia by cholangiovenous reflux, canine pancreatic juice or bile from a patient with choledochal cyst was injected into the obstructed common bile duct in dogs. The pancreatic enzymes in bile could readily enter into the blood stream at the pressure level of 15 mmHg or more in the bile duct. The peak amylase level in the thoracic lymph was observed to be more than 4 times higher than that in the blood serum, and the lymph flow during 30 minutes increased significantly from 8.1 to 20.4 ml at the bile duct pressure level of 20 mmHg. The reflux of amylase in bile into the blood stream via both the hepatic vein and thoracic duct might result in hyperamylasemia in the patients with choledochal cyst.

Characteristics of choledochal cysts in neonates and early infants

Thirty-six infants with choledochal cyst consisting of 28 babies less than 12 months of age and 8 between 13 and 24 months of age, were analyzed. Characteristics of cases were as follows: (1) they were usually of the cystic type, (2) a huge abdominal mass and jaundice with alcoholic stool were typically found, (3) no symptom suggesting acute pancreatitis was observed, (4) amylase levels in bile were usually low, despite the presence of pancreatobiliary malunion, while other pancreatic enzymes in bile commonly showed a high concentration, and (5) primary cyst excision and biliary reconstruction was the treatment of choice, and could be safely performed with favorable outcomes even in babies less than 1 year of age.

Biliary complications after excisional procedure for choledochal cyst

During the last 25 years, from 1969 to 1994, the authors treated 97 choledochal cysts by surgical excision. Biliary reconstruction consisted of 67 hepaticoduodenostomies and 30 hepaticojejunostomies. The common hepatic duct was the site of anastomosis in 9 of the duodenostomies and 13 of the jejunostomies and of the bifurcation of the hepatic ducts in 58 duodenostomies and 17 jejunostomies. Reoperation was required in 10 cases because of recurrent cholangitis with intrahepatic gallstones. Biliary strictures were responsible for the cholangitis in 9 children with anastomoses at the level of the common hepatic duct and in 1 with an anastomosis at the level of the bifurcation. These results suggest that biliary complications develop because of anastomotic stricture or primary ductal stricture, and may be minimised by the creation of a wide anastomosis, which is best accomplished at the hepatic hilum.

The effects of feeding and secretin administration on the pancreaticoduodenal papilla of conscious dogs

The aim of this study was to define the functional role of the pancreaticoduodenal papilla (PDP) in the regulation of pancreatic outflow into the duodenum in response to feeding and secretin administration in conscious dogs. The canine model we developed allowed for measurement of the pancreatic ductal pressure and pancreatic outflow simultaneously in a physiological state without interfering with the flow of pancreatic juice via the intact sphincter of the duodenal papilla. Feeding increased the pancreatic outflow from 2.8 +/- 0.2 to 13.4 +/- 1.3 ml/15 min with a slight increase in the pancreatic ductal pressure from 8.5 +/- 0.6 to 13.7 +/- 1.4 cmH2O. The administration of secretin increased the pancreatic outflow from 2.8 +/- 0.2 to 12.7 +/- 1.0 ml/15 min without increasing the pancreatic ductal pressure. The viscosity of the pancreatic juice increased during exposure to food, but decreased following food intake and secretin administration, after which the PDP seemed to dilate by about 40% of the fasting value. The results suggest that PDP changes its opening to maintain the pancreatic ductal pressure below a certain level, even if pancreatic secretion into the pancreatic duct increases due to food intake and secretin administration.

Successful left hepatectomy for hepatocellular carcinoma in a child after transcatheter arterial chemoembolization: report of a survival

A 12-year-old boy with large hepatocellular carcinoma is presented. The tumor was successfully resected after reducing the tumor size by transcatheter arterial embolization with Lipiodor containing an antitumor drug. The patient has achieved a 2-year-10-month disease-free survival.

Effects of pectin and cellulose on fat absorption after massive small-bowel resection in weanling rats

The effects of pectin and cellulose on fat absorption after massive small-bowel resection were studied in rats. Weanling Wistar rats underwent 80% resection of the small intestine with gastrostomy, and fat emulsion labeled with 14C-linoleate was given via a gastrostomy tube for the fat absorption test on the 10th postoperative day. They were classified into three groups by diet as follows: E group, a fiber-free, chemically defined diet (CDD); EP group, CDD with 2% pectin; and EC group, CDD with 2% cellulose. The cumulative and hourly output of 14C in the expired air, the absorption rate of 14C in the intestine, and the metabolic utilization rate of 14C were calculated. The cumulative 14CO2 output was significantly lower in the EC group than in the E and EP groups. However, there was no significant difference in the 14CO2 output between the E and EP groups. The highest hourly 14CO2 output in the E and EP groups was observed during the first 2 hours. However, in the EC group, this fluctuated at low levels. No significant difference in the 1-14C-linoleate absorption rate was observed between the E and EP groups, whereas it was significantly lower in the EC group than in the E and EP groups. The metabolic utilization rate of 1-14C-linoleate showed no significant difference among the three groups. These data suggest that an addition of pectin to CDD does not impair small intestinal absorption of 1-14C-linoleate after massive small-bowel resection, and an addition of cellulose decreases absorption of 1-14C-linoleate.

Lung scintigraphy with [123I]IMP in patients with pulmonary tuberculosis

Lung scintigraphy using N-isopropyl-p-[123I]iodoamphetamine (IMP) was performed on 26 patients with pulmonary tuberculosis. Early (5 min after injection) and late images (4 h after injection) were obtained with a large-field gamma-camera equipped with a digital computer. Lung scintigraphy using [99mTc]MAA (MAA) was also done. Although early IMP images showed the same findings as [99mTc]MAA, images, a discrepancy between delayed IMP images and [99mTc]MAA images was seen in some patients. Increment of activities seen in late images was demonstrated in most patients whose chest x-ray findings included exudative inflammatory changes. Uptake and clearance of IMP was considered to be affected by the active phase of pulmonary tuberculosis.

Effects of enteral fat emulsion on fat absorption in obstructive jaundiced rats

The effects of fat emulsion given enterally on fat absorption were studied with obstructive jaundiced rats (J group) as compared with jaundice-free rats (C group). The J and C groups were subdivided into JE and CE groups using emulsified fat for the fat absorption test, and JU and CU groups using unemulsified fat. Rats in all groups were fed for 7 days with regular rat chow. After fasting for 12 hours, 14C-labeled fat emulsion was infused to the JE and CE, and 14C-labeled unemulsified fat to the JU and CU groups through a gastrostomy for the absorption test. The hourly and cumulative output of 14CO2 by respiration, absorption rate of 14C-labeled fat in the intestine, and metabolic oxidation rate of the absorbed fat were determined during an 8-hour period after the gastroenteral administration of emulsified or unemulsified fat. The peak of hourly output was seen after the first 2 hours in the CE, JE, and CU groups, following which a remarkable decline was seen in the CE and CU groups. However, a more gentle descent in the JE, and fluctuation at a low level in the JU group were observed. The cumulative output in the JE was 61% of that in the CE, while the output in the JU was 16% of that in the CU group. The absorption rate in the JE was 81% of that in the CE group, while the rate in the JU was 22% of that in the Cu group.(ABSTRACT TRUNCATED AT 250 WORDS)

Reduced regional cerebral blood flow in aged noninsulin-dependent diabetic patients with no history of cerebrovascular disease: evaluation by N-isopropyl-123I-p-iodoamphetamine with single-photon emission computed tomography

Regional cerebral blood flow was measured using N-isopropyl-123I-iodoamphetamine with single-photon emission computed tomography (CT) in 16 aged patients with noninsulin-dependent diabetes mellitus (NIDDM, average age 72.8 years, average fasting plasma glucose 7.7 mmol/L), and 12 nondiabetic subjects (71.6 years, 5.3 mmol/L). None had any history of a cerebrovascular accident. Systolic blood pressure (SBP), total cholesterol, and triglyceride levels did not differ between groups. Areas of hypoperfusion were observed in 14 diabetic patients (12 patients had multiple lesions) and in 6 nondiabetic subjects (3 had multiple lesions). Areas where radioactivity was greater than or equal to 65% of the maximum count of the slice was defined as a region with normal cerebral blood flow (region of interest A, ROI-A), and areas where the count was greater than or equal to 45% were defined as brain tissue regions other than ventricles (ROI-B). The average ROI-A/B ratio of 16 slices was used as a semiquantitative indicator of normal cerebral blood flow throughout the entire brain. Mean ROI-A/B ratio was 49.6 +/- 1.7% in the diabetic group, significantly lower than the 57.9 +/- 1.6% at the nondiabetic group (p less than 0.005). The ratio was inversely correlated with SBP (r = -0.61, p less than 0.05), total cholesterol (r = -0.51, p less than 0.05), and atherogenic index (r = -0.64, p less than 0.01), and was positively correlated with high-density lipoprotein (HDL) cholesterol (r = 0.51, p less than 0.05) in the diabetic, but not the nondiabetic group. These observations suggest that the age-related reduction in cerebral blood flow may be accelerated by a combination of hyperglycemia plus other risk factors for atherosclerosis.

Serum lipid levels in thyroid dysfunction with special reference to transient elevation during treatment in hyperthyroid Graves' disease

Lipid metabolism was examined in patients with hyper- or hypothyroidism. Compared with corresponding age and sex matched controls, serum total cholesterol (T-chol), low density lipoprotein cholesterol (LDL-chol), phospholipid (PL) and LDL levels were significantly low and free fatty acid (FFA) levels were high with apparently normal triglyceride (TG), very low density lipoprotein (VLDL) and high density lipoprotein cholesterol (HDL-chol) levels in 61 hyperthyroid patients, while T-chol, LDL-chol, TG, PL, VLDL and LDL levels were high with normal FFA and HDL-chol levels in 31 hypothyroid patients. Serum lipid levels were then repeatedly measured in 7 men and 7 women with hyperthyroid Graves' disease before treatment (stage I), just after the patients became euthyroid with anti-thyroid drug (stage II) and more than 2 months after the patients remained euthyroid (stage III). Serum T-chol, LDL-chol, PL and LDL levels were low at stage I, significantly elevated at stage II and then normalized at stage III. Transient but significant elevation of serum TG, VLDL and HDL-chol levels at stage II were also observed in men. Accelerated catabolism and anabolism of lipid has been reported in hyperthyroidism. Transient elevation of serum lipid levels suggests a more rapid improvement in catabolism than in anabolism of lipid in an early stage of the medical treatment for hyperthyroidism.

Pseudopancreatitis in choledochal cyst in children: intraoperative study of amylase levels in the serum

A case of acute necrotizing pancreatitis in association with choledochal cyst is presented. Pancreatitis associated with choledochal cyst is probably caused by a biliary reflux into the pancreatic duct via a pancreatobiliary malunion, as the intraductal pressure of the cyst exceeds that of the pancreatic duct. Ampullar stenosis due to gallstones or inflammatory changes may increase the intraductal pressure. Bile with activated pancreatic enzymes refluxes into the pancreatic duct, and possibly results in acute pancreatitis. However, patients with choledochal cyst presenting with recurrent bouts of abdominal pain, vomiting, and fever have often been diagnosed as having acute pancreatitis because of hyperamylasemia, despite no evidence of pancreatitis at the time of surgery. At the time of bouts, they also show a slight elevation of serum bilirubin, and an increase in the degree of the choledochal dilatation that are possibly caused by biliary obstruction, not ampullar obstruction, due to suppurative cholangitis. The term "fictitious pancreatitis" or "pseudopancreatitis" in choledochal cyst appears to be appropriate. This clinical study shows that amylase in the biliary tract has ready access to the blood stream, probably through a sinusoidal pathway by cholangiovenous reflux, and a lymphatic pathway, via the Disse's space and denuded cyst wall, provided the biliary ductal pressure is increased.

Posterior tibial somatosensory evoked potentials in Duchenne-type progressive muscular dystrophy

Posterior tibial somatosensory evoked potentials were recorded from 10 patients with Duchenne-type progressive muscular dystrophy (DMD). The results of the patients were compared with age-matched controls. The ratio of height to latency (H/P38 and H/N22-P38) decreased significantly in DMD, which indicated central conduction disturbances in DMD.

Male siblings with Takayasu's arteritis suggest genetic etiology

Takayasu's arteritis is a nonspecific arteritis involving the aorta and its major branches. The disease mainly affects young females and familial incidence is uncommon. In this paper, two rare cases of male siblings with Takayasu's arteritis and the results of their HLA typing are described. The HLA haplotype of the two cases was completely identical--A2-B40-Cwl and A24(9)-Bw59-Cwl, DR2, and DR4. It is reported that Bw52(5) is strongly associated with the disease. However, in our cases, Bw52(5) was not found, while DR2 and DR4, which have been reported in association with several autoimmune disease, were detected. Accordingly, in these cases, genetic factors might be associated with the pathogenesis of the disease through an autoimmune mechanism.

Hemodynamic and hormonal effects of propranolol on patients with essential hypertension during head-up tilting: a comparison between normal and low cardiac index groups

Twelve outpatients with essential hypertension who showed a normal cardiac index (CI) (between 2.5 and 3.6 1/min/m2) or low CI (2.5 and less 1/min/m2) were studied. Head-up tilting (70 degrees) was performed for 15 min before and 2 weeks after treatment with propranolol (90 mg/day). Before treatment, the normal CI group showed a fall in systolic blood pressure (SBP) associated with a decrease in CI and an increase in the total peripheral resistance index (TPRI) during tilting. Conversely, the low CI group showed a rise in SBP associated with an increase in CI and a decrease in TPRI. There was a negative correlation (r = -0.69, P less than 0.05) between the basal CI and the change caused by the tilting. During treatment with propranolol, on the other hand, both groups showed decreases in CI. There was a greater increase in plasma renin activity (PRA) in the normal than in the low CI group before treatment with propranolol. The rise in PRA was significantly (P less than 0.05) suppressed by propranolol in the normal CI group only. It was demonstrated that the low CI group showed a different hemodynamic response to the tilting than the normal CI group. The lower rise in PRA may have partially contributed to the lack of increase in TPRI in the low CI group, compared with the normal CI group. Such hemodynamic differences may be abolished by propranolol which has a cardioinhibitory and/or renin-suppressive effect.

Suppressive effect of captopril on platelet aggregation in essential hypertension

Effects of captopril on platelet aggregation were studied in 12 essential hypertensive subjects. At the same time, the effects of captopril and angiotensin II on platelet aggregation in vitro were examined in 20 volunteers. A 50-mg oral dose of captopril was administered daily to hypertensive subjects for 2 weeks; the dose was then increased to 100 mg daily for the next 2 weeks. Values of platelet aggregation induced by ADP, epinephrine, collagen, and arachidonic acid before captopril treatment were 71.9 +/- 4.5, 77.3 +/- 4.2, 72.4 +/- 4.1, and 70.8 +/- 4.3% (mean +/- SE), respectively. Two weeks after daily administration of 50 mg captopril, these values were 56.7 +/- 4.5, 50.8 +/- 7.6, 64.0 +/- 4.6, and 60.9 +/- 3.9%, respectively, with significant reduction of platelet aggregation (p less than 0.001, p less than 0.01, p less than 0.01, and p less than 0.005, respectively). Daily administration of 100 mg captopril also had a significant suppressive effect on platelet aggregation. Changes of platelet count and serum lipids were not significant. In vitro, captopril and angiotensin II added to platelet-rich plasma had no effect on platelet aggregation. These results show that the suppressive effect of captopril on platelet aggregation is a secondary action in vivo.

Haemodynamic and hormonal effects of prazosin on head-up tilt in essential hypertensive patients: comparison with those of propranolol

To evaluate the haemodynamic and hormonal effects of prazosin, head-up tilt was performed in 10 essential hypertensive patients, and these effects of prazosin on the tilt were compared with those of propranolol. The tilts were performed in control phase and the last days of treatment for two weeks with propranolol (90 mg/day) or prazosin (3-6 mg/day). Each drug significantly lowered the mean blood pressure at rest, and also suppressed its rise on the tilt. Heart rates were significantly increased by the tilt in the control phase, in the propranolol phase and in the prazosin phase. Cardiac index was significantly reduced by the tilt from 2.66 (s.e.m. = 0.22) 1/min per m2 to 2.08 (s.e.m. = 0.20) in the propranolol phase. However, there were not significant changes in other phases. Total peripheral resistance indices were significantly increased by the tilt in all three phases. Plasma renin activity and plasma aldosterone were significantly increased by the tilt from 2.14 (s.e.m. = 0.47) ng/ml per h to 2.46 (s.e.m. = 0.54) and from 50.6 (s.e.m. = 12.9) pg/ml to 74.9 (s.e.m. = 14.9) respectively, in the control phase. And they were also significantly increased from 1.06 (s.e.m. = 0.29) to 1.65 (s.e.m. = 0.45) and from 41.4 (s.e.m. = 16.3) to 54.0 (s.e.m. = 17.4) in the prazosin phase. There were no significant increases during the administration of propranolol. We observed that prazosin did not alter heart rate and cardiac index, but suppressed the renin-angiotensin system at rest. It is suggested that prazosin did not influence haemodynamic and hormonal responses to the tilt.

Brain metabolism following bilateral carotid occlusion in 2 different models of experimental hypertensive rats

Brain metabolites and arterial acid-base measurements were made one hr after bilateral carotid artery occlusion in 2 different models of hypertensive rats. Animals used included renovascular hypertensive rats (RHR) with an altered renin-angiotensin system and desoxycorticosterone hypertensive rats (DHR) with low plasma renin activity (PRA). The mean value for supratentorial lactate of 7.41 mM/kg in RHR was significantly higher than in DHR (3.90 MM/kg) or in control normotensive rats (3.10 - 2.56 mM/kg). Concomitantly, the lactate/pyruvate ratio tended to increase and ATP to decrease in RHR only. In these same rats (RHR) infratentorial lactate was also increased. The results suggest that bilateral carotid occlusion leads to anaerobic metabolism of the brain in RHR but not in DHR, suggesting that the renin-angiotensin system may play some role in the susceptibility to cerebral ischemia following carotid occlusion in the hypertensive rats.

Brain metabolism and arterial acid-base balance following bilateral carotid occlusion in normotensive and experimental hypertensive rats

The effects of bilateral common carotid artery occlusion on brain metabolism and arterial acid-base balance were studied in normotensive and experimental renovascular hypertensive rats. One hour after carotid occlusion in hypertensive rats, supratentorial lactate increased to 383% and lactate-pyruvate ratio to 280% of the controls, while adenosine triphosphate (ATP) decreased to 69%. These metabolic changes were thought to be due to cerebral ischemia. Arterial pCO2 was lowered and the pH was raised in the hypertensive animals due to cerebral ischemia induced hyperventilation. In the normotensive rats, carotid occlusion had minimal effects on cerebral metabolism and arterial acid-base balance. These results suggest that hypertensive rats are more susceptible to cerebral ischemia caused by carotid occlusion than normotensive rats. Increased cerebrovascular resistance in hypertension is discussed as a causal factor in cerebral ischemia.

Effect of carotid artery ligation on regional cerebral blood flow in normotensive and spontaneously hypertensive rats

Regional cerebral blood flow (rCBF) was measured in normotensive rate (NTR) and spontaneously hypertensive rats (SHR), in a lightly anesthetized state and with control of PaCO2 by artificial ventilation. Without carotid artery ligation, NTR and SHR showed almost identical rCBF values and distribution, despite significantly elevated levels of blood pressure in SHR. Bilateral carotid artery ligation, however, caused much more pronounced decreases of rCBF (ischemia) in SHR than NTR, in regions supplied by the carotid artery. The reduction of rCBF in SHR was rather homogenous and symmetrical. Mechanisms causing the differences between NTR and SHR are discussed.

Cerebral infarction following bilateral carotid artery ligation in normotensive and spontaneously hypertensive rats: a pathological study

A pathological examination was performed on normotensive rats (NTR) and spontaneously hypertensive rats (SHR) following bilateral common carotid artery ligation. After ligation, diffuse and extensive cerebral infarcts in the carotid artery territory occurred frequently in SHR, while NTR occasionally had well-circumscribed small infarcts. The posterior communicating arteries, which are the major anastomotic channels connecting the carotid and vertebrobasilar systems, did not show any anomalies and were well developed in SHR and NTR. Vascular changes secondary to hypertension, such as fibrinoid necrosis or thickening of the wall, were not observed in SHR. Because of the paucity of structural difference of the blood vessels, the more diffuse and extensive cerebral infarcts in SHR after carotid occlusion were attributed to the hemodynamic difference rather than the morphological difference between the two groups. The results of the present experiment suggest that hypertension per se, i.e., hemodynamic factors, may be operative for the development of cerebral infarction.