Effects of FK506, an immunosuppressive agent, on genesis of water-immersion stress-induced gastric lesions in rats

We examined the effects of FK506, an immunosuppressive agent, on the genesis of water immersion stress-induced gastric lesions in rats. Using high-performance liquid chromatography, four kinds of prostaglandins, ie, 6-keto-prostaglandin F1 alpha, prostaglandin F2 alpha, prostaglandin E2, and prostaglandin D2, were detected, and no leukotrienes were detected in gastric mucosa in rats without stress. After 6 hr of stress, gastric lesions developed with decreases in all prostaglandin contents, and the emergence of peptide leukotrienes was observed. Intramuscular administration of FK506 (0.1, 0.25, 0.5, 1.0, and 2.0 mg/kg) reduced lesion index dose-dependently. Administration of FK506 at doses over 0.25 mg/kg decreased all prostaglandin contents, but did not affect the increase in leukotriene contents. Pretreatment with famotidine or omeprazole reduced lesion index, and the protective effects were equivalent to those of 1.0 mg/kg of FK506, although FK506 did not affect gastric secretion during water-immersion stress. Water-immersion stress did not change the activities of xanthine oxidase in either stomach or serum. Polyoxyethylene-modified superoxide dismutase did not prevent gastric lesions. Water-immersion stress significantly increased myeloperoxidase activity in gastric mucosa, and FK506 reduced the increase in myeloperoxidase activity induced by stress. From our results, other factors besides gastric acid secretion and tissue eicosanoid contents, such as chemoattractant factor, might also be involved in the genesis of water-immersion stress-induced gastric lesions in rats.

Paradoxical embolism as a cause of ischemic stroke of uncertain etiology. A transcranial Doppler sonographic study

BACKGROUND AND PURPOSE

This study was designed to test the hypothesis that paradoxical embolization would be a cause of embolic strokes and transient ischemic attacks in patients with stroke of uncertain etiology in all age groups.

METHODS

Thirty patients who had stroke of uncertain etiology were studied. They were divided into the following three groups: 13 patients with sudden onset (group A), 11 patients with subacute onset (group B), and 6 asymptomatic stroke patients (group C). Eleven patients with stroke of obvious etiology (group D) and 11 normal healthy volunteers (group E) were also studied as controls. In all patients transcranial Doppler sonography and contrast echocardiography were recorded simultaneously after intravenous injection of the contrast medium. Findings of positive patient foramen ovale in contrast echocardiography or "chirp" sounds in transcranial Doppler sonography were defined as positive for paradoxical contrast embolization. Radioisotope phlebography of the lower extremities and pulmonary scintigraphy, using technetium-99 macroaggregated albumin, were performed in all 17 patients who had positive findings of paradoxical contrast embolization and in 12 patients whose findings were negative.

RESULTS

Positive findings of paradoxical contrast embolization were found in 17 subjects by transcranial Doppler sonography but in only 8 on contrast echocardiography. These positive findings were detected more frequently in group A (77%) than in groups B, D, and E (9%, 18%, and 9%, respectively) (P < .05). In group C, 4 of 6 patients (67%) had positive findings. There were positive findings on both phlebography and pulmonary scintigraphy only in 6 group A patients, with positive findings of paradoxical contrast embolization.

CONCLUSIONS

Transcranial Doppler sonography is a sensitive detector of right-to-left shunts. Paradoxical cerebral embolization might be frequent in patients with stroke of unknown etiology, especially when the stroke is of sudden onset.

[The relationship between titrated acidity (mEq/l) and pH of human gastric juice: a study based on the data estimated by pH-meter]

The relationship between titrated acidity and pH was studied using the 3206 samples of human gastric juice, which were collected by the intragastric tube in the basal and gastrin stimulated conditions. The pH of samples subjected to the present study ranged from 0.95 and 6.9. The results showed that a certain value of pH did not always indicate an identical value of titrated acidity, and that the coefficient of variation was greater as pH value rose. As a whole, however, the acidity became lower with the increase of pH value. Thus, the relationship between pH and titrated acidity could be expressed closely as "Y = 369.19 - 424.09X + 203.66X2 - 48.29X3 + 5.57X4 - 0.25X5), where X = pH and Y = acidity. The conversion table from pH to acidity, which was calculated by this expression, was presented for the clinical use.

Differential diagnosis of pancreatic diseases with an intraductal ultrasound system

Forty patients with pancreatic diseases (11 cancer, 1 islet cell tumor, 12 mucin-producing tumor, 1 teratoma, and 15 chronic pancreatitis) were studied in vivo with ERP and were also scanned with an intraductal ultrasound (IDUS) probe at a frequency of 30 MHz inserted into the main pancreatic duct. The usefulness of in vivo IDUS was evaluated by comparison of images with the ERP findings. IDUS was of diagnostic value in 18 of the 40 patients; it distinguished between 4 malignant and 6 benign causes of localized stenosis revealed by ERP, provided parenchymal information in 2 cases with only displacement revealed by ERP (1 islet cell tumor and 1 teratoma), and determined the extent of tumor in 6 cases with main-duct-type mucin-producing tumor. Ten of 11 cancer, 4 of 12 mucin-producing tumor, 1 islet cell tumor, and 11 of 15 chronic pancreatitis (previously scanned in vivo), and 2 islet cell tumor (not scanned in vivo), were resected and scanned in vitro. Fifteen normal pancreases from autopsy subjects were also scanned in vitro. The IDUS images were then compared with corresponding histopathological sections from the 15 normal pancreases and 28 post-operative pancreatic specimens. Differential diagnosis of the pancreatic diseases by echo patterns was possible in all cases except those with intraductal papillary adenocarcinoma and adenoma.

New technique using intraductal ultrasonography for the diagnosis of bile duct cancer

We investigated the extent to which BDca can be visualized and diagnosed via a percutaneous fistula using IDUS. IDUS was performed in 42 cases, including 15 of normal bile ducts; 12 of choledocholithiasis, and 15 of BDca. The depth of invasion of the BDca was diagnosed with a 93% accuracy rate by visualizing the EP or MA or both. The infiltration of BDca into the surrounding organs was clearly visualized and diagnosed with an accuracy of 100% in the RHA, 93% in the PV, and 93% in the pancreas. These accuracy rates were higher than those obtained by computed tomography or angiography. We believe, therefore, that IDUS should be further studied as a diagnostic modality for staging malignancy in the biliary field.

Asymptomatic carotid lesions and silent cerebral infarction

BACKGROUND AND PURPOSE

Few studies have investigated the relationships between asymptomatic carotid lesions and silent infarcts confirmed on magnetic resonance imaging.

METHODS

A consecutive series of 117 subjects (average age, 62 +/- 9.4 years) who were free from neurological deficit but had at least one established risk factor for stroke were investigated by B-mode carotid ultrasonography and magnetic resonance imaging of the brain. Carotid lesions were evaluated by plaque score, maximum percent stenosis, and the existence of ulcerated lesions. The relations between the carotid lesions and the incidence, size, or localization of the brain lesions were investigated.

RESULTS

The incidence of silent infarcts was 42% in all subjects and significantly increased with advancing age (P < .05). Most lesions were smaller than 1 cm in diameter and were usually localized in the subcortical white matter or the basal ganglia. The percentage of subjects with infarcts increased significantly as the plaque score increased (P < .05) or when subjects had high-grade stenosis (P < .05) or ulcerated lesions (P < .01). These relationships were also noted in each decade of age. A higher incidence of larger lesions (> 1 cm) was found in the brain hemisphere ipsilateral to the carotid lesion, particularly in subjects with high-grade stenosis or ulcerated lesions (P < .01). Multivariate analysis indicated significant correlations with silent infarcts for age, hypertension, and plaque score.

CONCLUSIONS

Both the severity and characteristics of asymptomatic carotid lesions estimated by B-mode ultrasonography were closely related to the appearance of silent infarcts. These results demonstrate that noninvasive assessment of carotid lesions can be useful in predicting the existence of silent cerebral infarction even in patients free from neurological deficits.

Characterization of a Rana catesbeiana lectin-resistant mutant of leukemia P388 cells

Sialic acid-binding lectin (SBL-C) from Rana catesbeiana eggs inhibits the growth of tumor cells such as P388 and L1210 leukemia cells (K. Nitta et al., Cancer Res., 54: 920-927, 1994). Here we report the establishment of an SBL-resistant P388 variant cell line, RC-150. Both P388 and RC-150 cells were agglutinated by SBL-C; however, growth of RC-150 cells was unaffected by SBL-C. Cytoplasmic free Ca2+ concentration and transglutaminase activity of RC-150 cells were 0.5 (110 nM) and 3 times (0.62 nmol/mg/min) as high as those of P388 cells, respectively. Microvilli and microplicae were observed on the surface of P388 cells by scanning electron microscopy but were rarely seen on RC-150 cells. Dansylcadaverine-labeled SBL-C bound to both P388 and RC-150 cells. Binding of SBL-C to these tumor cells appears to be mediated by two species of wheat germ agglutinin-stained cell membrane sialoglycoproteins. Labeled SBL-C entered P388 but not RC-150 cells, suggesting that internalized SBL-C acts as an inhibitor of cell proliferation.

[Partial purification and properties of deoxyribonucleases from eggs and liver of Xenopus laevis. Comparison with deoxyribonuclease II from bovine spleen]

Deoxyribonucleases from eggs and the liver of Xenopus laevis were partially purified by DEAE-cellulose and heparin-Sepharose affinity column chromatographies. The fractions having egg and liver DNase activities were eluted on high performance liquid chromatography through TSK gel G3000SW at the molecular weights of 41.5 and 45 kDa, respectively. The frog DNases hydrolyzed a native DNA over a heat-denatured DNA, and also formed double-strand cuts not only in linear lambda-DNA but also in closed circular pBR322DNA. The pH optimum of the DNases was 4.5-5.0 in 50 mM acetate buffer. These enzyme activities were abolished by treatment at 80 degrees C for 5 min and pH 2, 3 or 12 for 1 h. The enzymes act in such a manner as deoxyribonuclease II (from bovine spleen)-type nuclease with respect to substrate specificity, optimum pH and cation dependence.

[Adaptation and effects of ileal reservoir on ileo-proctostomy following total colectomy in dogs]

We examined postoperative adaptation and effects of J-pouch reservoir on ileo-proctostomy following total colectomy in dogs. End to end (E-E; n = 5) or J-pouch (J-P; n = 5) anastomosis was performed after resection of total colon and the rectum 3 cm above the peritoneal reflexion. Gastrointestinal motility with strain gauge force transducers (SG) and transit time with barium meal under the fluoroscopy were recorded 6 months after total colectomy. Then, histological changes of seven specimens from totally resected ileum in J-P and E-E vs control (normal ileum; n = 5) were measured with hematoxylin-eosin and PYY immunohistochemical stains. Propagation rate of interdigestive migrating complex (IMC) from jejunum to ileum was significantly lower in J-P (64.8 +/- 13.2%) than in E-E (98.6 +/- 1.2%) (p < 0.001). Oro-neorectal transit time (ONTT) in E-E (138 +/- 10 min) was shorter (p < 0.05), but ONTT in J-P (189 +/- 26 min) was significantly longer (p < 0.01) than oro-caecal transit time (OCTT) in preoperative control (165 +/- 19 min; n = 10). There was no difference about length of villi among control, E-E and J-P, but length of crypts in J-P (0.59 +/- 0.08 mm) was longer than that in E-E (0.27 +/- 0.02 mm) and normal ileum (0.34 +/- 0.07 mm) (p < 0.01). PYY positive cells in J-P were more than in E-E and control at any site of ileum and total number of PYY positive cells in J-P (168 +/- 18) significantly increased than that in E-E (111 +/- 16) and control (103 +/- 14) (p < 0.05). Thus, increase of PYY positive cells in J-P inhibits gastrointestinal motility and transit. Delayed transit time and crypts elongation were intestinal adaptation that assists the absorption of luminal contents. Therefore, it suggested that J-pouch reservoir had advantage to ileo-proctostomy following total colectomy in dogs.

Reactivity of cerebral blood flow to carbon dioxide in hypertensive patients: evaluation by the transcranial Doppler method

OBJECTIVE

To evaluate hypertensive cerebral involvement before cerebrovascular accidents.

DESIGN

Cerebral microvascular responses to changes in the arterial partial pressure of CO2 (pCO2; the CO2 reactivity) were compared among patients with different stages and severity of hypertensive disease.

PATIENTS

Fifty-eight patients with hypertension, 11 with borderline hypertension, 15 hypertensives with cerebral infarction and 58 normotensive controls were studied.

METHODS

The cerebrovascular CO2 reactivity was determined by measuring simultaneously the end-tidal pCO2 and the blood flow velocity in the middle cerebral artery using transcranial Doppler sonography under hypocapnic, normocapnic and hypercapnic conditions.

RESULTS

CO2 reactivity was impaired in the hypertensive patients compared with in the normotensive controls, but less so than in the symptomatic hemisphere of the hypertensive patients with cerebral infarction. The CO2 reactivity in the borderline hypertensive patients was greater than that in both the symptomatic and asymptomatic hemispheres of the hypertensive patients with cerebral infarction. In the subjects without cerebral infarction, two risk factors for cerebral atherosclerosis (age and hypertension) were negatively correlated with cerebrovascular CO2 reactivity. In the hypertensive patients age and the estimated duration of hypertension were negatively correlated with cerebrovascular CO2 reactivity. CO2 reactivity in the patients with hypertensive or arteriosclerotic retinopathy or ST-T changes on their electrocardiogram was impaired compared with that in the patients without such changes.

CONCLUSIONS

Hypertension affected the microvascular reactivity of the brain before the development of cerebrovascular accidents, and its effect varied dependently on the extent of involvement of other target organs.

Study on the acceleration in healing of ethanol-induced gastric lesions in rats by methylprednisolone

This study was designed to determine the influences of methylprednisolone (MP, CAS 2375-03-3) on the genesis and healing of gastric lesions induced by 50% ethanol in relation to the changes in gastric mucosal prostaglandin (PG) and leukotriene (LT) contents and vascular permeability. Intragastric administration of 1 ml of 50% ethanol induced hemorrhagic lesions in the fundic portion, and these lesions were not affected by 20 mg/kg of MP injected subcutaneously 30 min before ethanol administration. In untreated rats, 4 kinds of PGs, i.e., 6-keto-PGF1a, PGF2a, PGE2, and PGD2, were determined in gastric mucosa by high performance liquid chromatography (HPLC), but no LTs were detected. Administration of ethanol significantly reduced all PG contents and increased production of peptide-LTs in gastric mucosa. Pretreatment with MP did not influence ethanol-induced changes in PG and peptide-LT contents. Ethanol-induced lesions required 96 h for total healing. Ulcer healing was not affected by MP, which was injected subcutaneously twice daily from 1 h after ethanol administration until the end of the experiment, and complete ulcer healing was observed after 72 h. MP did not affect ethanol-induced decrease in PG contents, their recoveries, or peptide-LT contents. Ethanol increased vascular permeability and MP reduced this increase. These results suggest that MP does not have a hazardous effect, but is rather beneficial with regard to healing of ethanol-induced gastric lesions through prevention of the increase in vascular permeability caused by ethanol, and that it affected neither gastric mucosal PG nor peptide-LT contents.

Evaluation of intraductal ultrasonography in the diagnosis of pancreatic cancer

An intraductal ultrasound (IDUS) probe which is inserted via the papilla into the main pancreatic duct (MPD) was evaluated in the diagnosis of 20 patients with pancreatic cancer. The examination was successfully performed with the probe in 17 of the patients (85%). Due to its high frequency (30 MHz) the probe only allowed visualization of the ductal wall and the immediate periductal vicinity (up to about 10 mm). In 15 of the 20 patients the tumors were surgically resected and IDUS scanning was also performed in vitro on the resection specimens, the results being compared to those of histopathological examination. Of these 15 patients, 13 were found to have ductal adenocarcinomas and all but one had been unequivocally diagnosed as having such by ultrasonography (US), computed tomography (CT), endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic ultrasonography (EUS). IDUS showed an echorich area (corresponding to cancerous canaliculi on histopathological examination), surrounded by an echopoor area (abundant stroma). This pattern was classified as type I. In two patients with intraductal papillary carcinomas in whom a conclusive diagnosis was not established on US, CT, EUS or ERCP, IDUS showed tumorous tissue with an inhomogeneous echopattern outside (type II) or within (type III) the duct. These results show that IDUS offers valuable diagnostic information complementary to ERCP especially in cases of intraductal papillary tumors. Whether the high resolution imaging of the duct and the paraductal tissue can be used to differentiate between the different forms of pancreatic lesions (inflammation, neoplasms) has to be investigated further.

Short report: effect of sucralfate on angiogenesis in granulation tissue of acetic acid-induced gastric ulcers in rats

We investigated the effect of sucralfate on angiogenesis in granulation tissue of gastric ulcers induced by acetic acid in rats using the carmine dye method. Intragastric administration of sucralfate at a dose of 500 mg/kg twice daily for 9 days significantly accelerated ulcer healing and significantly increased the extent of angiogenesis in the ulcer base on the tenth day after ulcer induction. As we reported previously, intragastric administration of cimetidine at a dose of 100 mg/kg once daily for 9 days decreased the extent of angiogenesis on the tenth day. However, combination treatment using sucralfate and cimetidine accelerated ulcer healing significantly, without altering the extent of angiogenesis. It is concluded, therefore, that the treatment with sucralfate may be effective in peptic ulcer disease from the standpoint of angiogenesis in the ulcer base.

Influence of irritants on lymph node cell proliferation and the detection of contact sensitivity to metal salts in the murine local lymph node assay

Dimethyl sulfoxide (DMSO) and sodium lauryl sulfate (SLS) are known to cause irritation of the skin, and to enhance the penetration of chemicals into the epidermis. In the present study, the lymph node cell (LNC) proliferative response following exposure to irritants, such as SLS and DMSO, was examined in the murine local lymph node assay (LLNA). Exposure to DMSO or SLS aqueous solution induced a small increase in lymph node cell proliferation compared with aqueous solution alone. Exposure to SLS in DMSO caused a significant increase in LNC proliferation. Further, the effect of addition of the irritants in a vehicle on the detection of contact sensitivity to metal allergens was examined. Application of potassium dichromate and nickel sulfate in DMSO or SLS aqueous solution caused increases in LNC proliferation. Exposure to metal allergen with SLS in DMSO also induced a significant LNC proliferative response, but did not induce a significant increase in stimulation index (increase in 3H-thymidine incorporation relative to vehicle-treated control group). This was because of increased 3H-thymidine incorporation following exposure to SLS-DMSO in the control group. These results suggest that irritants enhance the LNC proliferative responses to metal allergens. The use of SLS in aqueous solution is effective for the detection of sensitivity to water-soluble allergens, such as metal allergens, in the LLNA, as well as the use of DMSO as an application vehicle.

Increase of mannose residues, as Salmonella typhimurium-adhering factor, on the cecal mucosa of germ-free chickens infected with Eimeria tenella

To study increase of the Salmonella population in the cecum of chickens infected with Eimeria tenella, quantitative changes in mannose residues on the cecal mucosa were investigated. Inhibition of S typhimurium adherence to the cecum by a 2% carbohydrate (D-mannose, D-galactose, L-fucose, alpha-methyl-D-glucoside) in phosphate-buffered saline solution was examined. Only D-mannose had inhibitory effects. Whereas, D-galactose had somewhat enhancing effects on adherence of S typhimurium to the cecal mucosa of uninfected germ-free chickens. In infected and uninfected chickens, D-mannose inhibited adherence of S typhimurium. D-Mannose significantly (P < 0.05) increased adherence of Bacteroides sp. In infected and uninfected chickens, D-mannose did not have any effect on adherence of Clostridium perfringens and Bifidobacterium thermophilum. Under microscopic observation, only concanavalin A and Lens culinaris agglutinin, of 8 lectins examined, were recognized as lectin-positive staining lines or spots in the cecal mucosa, indicating presence of mannose residues on the cecal mucosa. In E tenella-infected chickens, lectin-positive staining was seen strongly on the coarse surface of damaged cells and at the bottom of the crypts. These results indicate that coccidial infection may induce increase of mannose residues on the intestinal surface and allow adhesion of more salmonellae to the intestine.

The use of robotics technology to study human joint kinematics: a new methodology

Robotics technologies have been modified to control and measure both the force and position of synovial joints for the study of joint kinematics. One such system was developed to perform kinematic testing of a human joint. A 6-axis articulated robotic manipulator with 6 degrees of freedom (DOF) of motion was designed and constructed; a mathematical description for joint force and position was devised; and hardware and software to control forces applied to the joint, as well as position of the joint, were developed. The new methodology was utilized to simulate physiological loading conditions and to perform an anterior-posterior (A-P) translation test on a human cadaveric knee. Testing showed that this new system can stimulate complex loading conditions and also measure the resulting joint kinematics.

Fractures of the hook of the hamate in athletes. 8 cases followed for 6 years

In 8 cases the fractured hook of the hamate was excised. Associated conditions included rupture of flexor tendons in 3 cases and ulnar nerve paresthesia in 2 cases. In 5 cases tomography was required to establish the diagnosis. Postoperative results with 6 years follow-up were good.

Rate of successful recording of blood flow signals in the middle cerebral artery using transcranial Doppler sonography

BACKGROUND AND PURPOSE

To assess the usefulness of transcranial Doppler sonography, we investigated the rate of blood flow signal recording failure in the middle cerebral artery in Japanese subjects. Furthermore, we studied the effect of increased emitted power on the rate of successful recording in some of the patients in whom recording failure had been detected at the standard transducer power of 100 mW/cm2.

METHODS

To evaluate the rate of successful recording, we measured blood flow signals in 597 patients (age range, 16 to 89 years) for screening of cerebrovascular disease by using a 2-MHz range-gated, pulsed-wave Doppler instrument at the standard transducer power. In 18 elderly patients with recording failure at the standard power, we assessed the effect of increased emitted power of 400 mW/cm2 on flow signal recording.

RESULTS

Blood flow signals were recorded in 920 (77.1%) of the 1194 middle cerebral arteries of the 597 patients studied. The rate of successful recording of bilateral middle cerebral artery flow signals (70.9%; 423 of 597 patients) decreased with age, especially in females (17.0% in women aged 70 years or older). In 12 of 18 elderly patients with recording failure at the standard power, blood flow signals could be detected at the increased emitted power of 400 mW/cm2.

CONCLUSIONS

The rate of successful recording of blood flow signals in Japanese subjects decreases with advancing age, especially in females. Increasing the emitted power markedly improves the successful recording rate.

Surgical resection for pyriform sinus fistula

There has been no established operative procedure for pyriform sinus fistula because of its rarity. Recurrence may occur even after neck exploration. We successfully managed six pediatric cases with this disease without any complications or recurrences. Our experience indicates that exposing the inferior cornu of thyroid cartilage with its covering muscles facilitates resection of the proximal portion of this fistula.

Carcinoid tumors of the gastrointestinal tract: evaluation with endoscopic ultrasonography

To evaluate the usefulness of endoscopic ultrasonography for carcinoid tumors, we examined 29 patients with gastrointestinal carcinoid tumors (5 gastric, 7 duodenal, and 17 rectal). The smallest size detectable by endoscopic ultrasonography was 2 mm in diameter histologically. The cross-sectional image of the tumors was primarily oval to round. The internal echo was generally hypoechoic and homogeneous. The margins were clearly visualized, and the contour was somewhat smooth. The tumors were mainly located in the third layer. The second layer covered the tumor with the third layer at its base, and it abutted the tumor and became indistinct near its upper interface. These findings were especially recognized in lesions with submucosal invasion and were similar at all sites. The overall accuracy of determining the depth of invasion using endoscopic ultrasonography was 75% (27 of 36 lesions). Limited to the lesions detectable by endoscopic ultrasonography, the accuracy was 90%. Endoscopic ultrasonography was useful in determining the presence of local metastases. Moreover, endoscopic ultrasonography allowed direct detection of perigastrointestinal lymph node metastases (75%, three of four patients). In conclusion, endoscopic ultrasonography was found to be useful for the staging of gastrointestinal carcinoid tumors by determining depth of involvement and presence of perigastrointestinal lymph node metastases.

Reactivity of cerebral blood flow to carbon dioxide in various types of ischemic cerebrovascular disease: evaluation by the transcranial Doppler method

BACKGROUND AND PURPOSE

The response of cerebral blood flow to changes in the arterial carbon dioxide partial pressure (i.e., carbon dioxide reactivity) has been evaluated as a parameter of cerebral perfusion reserve in patients with cerebrovascular disease. In this study, variations in this reactivity in various ischemic cerebrovascular diseases were evaluated by a newly established method, a transcranial Doppler technique.

METHODS

Thirty-three patients with symptomatic cerebrovascular disease, 13 patients with asymptomatic cerebral infarction, and 25 age-matched normal control subjects were investigated. The symptomatic patients were divided into three groups; those with unilateral carotid artery obstruction, those with cortical infarction, and those with lacunar infarction. The carbon dioxide reactivity of each subject was determined by simultaneously measuring the mean spatial Doppler frequency in the middle cerebral artery and the end-tidal carbon dioxide partial pressure under normocapnic, hypercapnic, and hypocapnic conditions.

RESULTS

In the patients with carotid obstruction, the carbon dioxide reactivity of the hemisphere ipsilateral to the obstruction was more impaired than the reactivity of the symptomatic hemispheres in any other group, and was significantly less than in the contralateral asymptomatic hemisphere (p < 0.01). In patients with cortical infarction, the carbon dioxide reactivity of the symptomatic hemisphere was significantly less than in normal control subjects (p < 0.05) and was also less than that of the contralateral asymptomatic hemisphere (p < 0.05). In patients with lacunar infarction, the carbon dioxide reactivity of both hemispheres was significantly less than that in normal controls (p < 0.01), although there was no difference between the symptomatic and asymptomatic hemispheres. In patients with asymptomatic infarction, the carbon dioxide reactivity was also less than that in normal controls (p < 0.01).

CONCLUSIONS

The carbon dioxide reactivity of cerebral blood flow measured by this transcranial Doppler technique may be useful for characterizing the hemodynamic changes that occur in various types of ischemic cerebrovascular disease.

Purification and some properties of ribonuclease from Xenopus laevis eggs

A 122 kDa RNase from eggs of Xenopus laevis was purified by sequential chromatography on Sephadex G-75, DEAE-cellulose, heparin-Sepharose and TSK gel G3000SW columns, and gave a single 60 kDa band on SDS-polyacrylamide gel electrophoresis under reducing and nonreducing conditions. The RNase composed of two 60 kDa subunits is able to recognize pyrimidine bases specifically. The pH optimum of the RNase was 7.5 in Tris-HCl buffer. The enzyme activity was abolished by treatment at 80 degrees C for 5 min and pH 2 or 12 for 1 h. Since egg lectins with RNase activity obtained from Rana catesbeiana and R. japonica and bovine pancreatic RNase A show about 30% protein homology and these three proteins are 12-14 kDa heat-stable RNases, [K. Titani, K. Takio, M. Kuwada, K. Nitta, F. Sakakibara, H. Kawauchi, G. Takayanagi and S. Hakomori, Biochemistry, 26, 2189 (1987); Y: Kamiya, F. Oyama, R. Oyama, F. Sakakibara, K. Nitta, H. Kawauchi, Y. Takayanagi and K. Titani, J. Biochem. (Tokyo), 108, 139 (1990)], the data suggest that the X. laevis egg RNase is a unique protein compared with RNases from not only amphibians, but also mammals.