A microbial chip combined with scanning electrochemical microscopy

A microbial chip for bioassay was fabricated and its performance was characterized by scanning electrochemical microscopy (SECM). The microbial chip was prepared by spotting a suspension of Escherichia coli on a polystyrene substrate by using a glass capillary pen. The respiration activity of the E. coli spot was imaged with SECM by mapping the oxygen concentration around the spot. The SECM images of the microbial chips clearly showed spots with lower reduction currents, indicating that E. coli in the spots uptake oxygen by respiration. The bactericidal effects of antibiotics (streptomycin and ampicillin) were measured using the E. coli-based microbial chip, and discussed in comparison with the minimum inhibitory concentration (MIC) determined by an agar plate dilution method.

Prevention of postoperative adhesion formation in rat uterine horn model by nimesulide: a selective COX-2 inhibitor

BACKGROUND

Pelvic surgery is one of the main causes of intraperitoneal (i.p.) adhesions that create various medical problems including pelvic pain, bowel obstructions and female infertility. A rat model was used to investigate the efficacy of nimesulide, a selective cyclooxygenase-2 inhibitor, in the prevention of adhesion formation.

METHODS

Fifty Wistar-Albino rats underwent bilateral uterine horn injury with a unipolar cautery. Study groups were as follows: (i) control group, no adjuvant therapy; (ii) i.p. Ringer's lactate group, 2 ml Ringer's lactate solution was instilled i.p.; (iii) i.p. Ringer's lactate plus nimesulide group, 1 ml Ringer's lactate plus 1 ml nimesulide (0.5 mg/ml) were given i.p.; (iv) intramuscular (i.m.) nimesulide group, 1 ml i.m. nimesulide (0.5 mg/ml) was given preoperatively for 5 days; and (v) i.p. nimesulide group, 1 ml nimesulide (0.5 mg/ml) was instilled i.p. At the end of the study all animals were killed, and a standard adhesion scoring system was applied by a blinded examiner.

RESULTS

The mean adhesion extent in study groups was as follows: 1.33 +/- 0.76 in control group, 1.40 +/- 0.90 in i.p. Ringer's lactate group, 0.75 +/- 0.70 in i.p. Ringer's lactate plus nimesulide group, 0.25 +/- 0.44 in i.m. nimesulide group and 0.31 +/- 0.70 in i.p. nimesulide group. The mean +/- SD adhesion severities of control, i.p. Ringer's lactate, i.p. Ringer's lactate plus nimesulide, i.m. nimesulide, and i.p. nimesulide groups were 0.58 +/- 0.35, 0.30 +/- 0.41, 0.27 +/- 0.3, 0.12 +/- 0.28 and 0.15 +/- 0.35 respectively. The lowest adhesions were found in the groups treated with nimesulide i.m. and nimesulide i.p. ( P < 0.05).

CONCLUSIONS

This study showed that preoperative i.m. or postoperative i.p. administration of nimesulide to the site of injury reduced the formation of postoperative adhesions in a rat uterine horn model.

Chloride channel blockers 5-nitro-2-(3-phenylpropylamino) benzoic acid and anthracene-9-carboxylic acid inhibit contractions of pregnant rat myometrium in vitro

OBJECTIVE

We compared in vitro relaxant effect of chloride channel modulators, such as 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) and anthracene-9-carboxylate (9-AC), and beta(2)-adrenergic agonists, such as ritodrine, in pregnant rat myometrium.

METHODS

Isolated myometrial strips were obtained from eight pregnant rats, and the strips were mounted in organ baths for recording isometric tension. The effects of 10(-8)-10(-4) M ritodrine, 10(-6)-3 x 10(-4) M NPPB, and 10(-6)-10(-3) M 9-AC on spontaneous contractions were recorded.

RESULTS

Ritodrine (10(-8)-10(-5) M) completely inhibited the amplitude and frequency of spontaneous contractions in myometrial strips isolated from pregnant rats in a concentration-dependent manner, but the relaxant effect of ritodrine at 10(-4) M concentration resulted in tachyphylaxis. The chloride channel blocker NPPB (10(-6)-3 x 10(-4) M) and the chloride transport inhibitor 9-AC (10(-5)-10(-3) M) decreased the amplitude of spontaneous myometrial contractions in a concentration-dependent manner; the maximum inhibition produced by the highest tested concentration of each drug was 43.8% and 42.1% of the original degree of spontaneous contractions, respectively. The frequency of myometrial contractions was significantly inhibited by NPPB and 9-AC beginning with the concentration of 10(-4) M.

CONCLUSION

NPPB and 9-AC appear to be effective relaxants of pregnant rat myometrium. These effects of NPPB and 9-AC might be therapeutically advantageous in clinical management of preterm labor.

Inhibitor effect of omeprazole in isolated human myometrial smooth muscle

The aim of the present study was to investigate the effect of omeprazole, an H+-K+-ATPase inhibitor, in myometrial smooth muscle strips from women undergoing elective caesarean section at term. Isolated myometrial strips taken with informed consent were obtained from eight pregnant women undergoing elective caesarean section at term (not in labour) and mounted in organ baths for recording of isometric tension. We recorded the effect of increasing concentrations of omeprazole on spontaneous and Ca2+-induced contractions of myometrial smooth muscle and on contractions of myometrial smooth muscle pretreated with indomethacin (3 x 10(-6) M) and L-NAME (3 x 10(-5) M). Omeprazole (10(-4)-10(-3) M) decreased the amplitude and frequency of spontaneous contractions in a time- and concentration-dependent manner in all myometrial smooth muscle isolated from pregnant women. The decrease in amplitude of contractions in myometrial smooth muscle reached statistical significance beginning from the concentration of 3 x 10(-4) M. Addition of indomethacin (3 x 10(-6) M) and L-NAME (3 x 10(-5) M) in to the organ baths 30 min before did not change relaxation responses to omeprazole. When 8 mM Ca2+-precontracted in Ca2+-free medium myometrial smooth muscle were exposed to increasing concentrations of omeprazole (10(-5)-10(-3) M), omeprazole produced relaxation responses in a time- and concentration-dependent manner, reaching statistical significance at 10(-4) M. These results show: (1) omeprazole time- and concentration-dependently decreased spontaneous contractile activity in myometrial smooth muscle isolated from pregnant women, (2) omeprazole-induced relaxations was not influenced by indomethacin and N(G)-nitro-L-arginine methyl ester (L-NAME), suggesting that it is not mediated by cyclooxygenase products and nitric oxide, and (3) omeprazole brought about time- and concentration-dependently relaxation of myometrial smooth muscle precontracted by 8 mM Ca2+ in Ca2+-free medium. This effect of omeprazole may be due to blockade of the calcium channels.

Hepatic adenomatosis: gadolinium-enhanced dynamic MR findings

Hepatic adenomatosis is a rarely encountered liver disease. It is an entity distinct from hepatocellular adenoma and is characterized by the presence of more than 10 hepatic adenomas. We present the multiplanar and multiphasic dynamic magnetic resonance findings of hepatic adenomatosis in a 15-year-old adolescent who developed transfusional hemosiderosis and had received anabolic steroids for the treatment of aplastic anemia.

Injury caused by deeply penetrating knife blade lodged in infratemporal fossa

Knife-inflicted, deeply penetrating head and neck trauma is an uncommon life-threatening injury and a challenging problem. An examination of the neurovascular and systemic physical status is a first requirement and the decision as to which approach to adopt for the removal of the blade is of critical importance. Here we report a rare case of a pre-auricular stab wound with the knife blade deeply lodged in the extracranial infratemporal fossa. Radiological investigations showed that the knife blade had entered from the temporomandibular joint and become lodged through the anterior margin of foremen magnum below the petrosal bone. Minimal left vocal cord paresis, left palatal weakness and a slight deviation of the tongue towards the left side were observed. The other neurological and systemic physical evaluations were normal. Simple withdrawal of the blade in the operating room did not cause serious neurovascular injury. Here we discuss and compare the expanded exposure of anatomical structures for blade removal and simple withdrawal in similar injuries.

In vitro and in vivo pharmacological characterization of JTE-907, a novel selective ligand for cannabinoid CB2 receptor

JTE-907 [N-(benzo[1,3]dioxol-5-ylmethyl)-7-methoxy-2-oxo-8-pentyloxy-1,2-dihydroquinoline-3-carboxamide] was evaluated in vitro and in vivo as a novel selective ligand for cannabinoid receptor of peripheral type (CB2). The compound binds with high affinity to human CB2 or mouse CB2 expressed on CHO cell membrane and to rat CB2 on splenocytes. The K(i) affinities for human, mouse, and rat CB2 were 35.9, 1.55, and 0.38 nM, respectively. The selectivity ratio for the CB2 receptors compared with central nervous type receptors (CB1) of human (expressed on CHO cells), and mouse and rat CB1 on cerebellum were 66, 684, and 2760, respectively. JTE-907 showed concentration-dependent increase of forskolin-stimulated cAMP production in CHO cells expressing human and mouse CB2 in vitro, i.e., JTE-907 behaved as an inverse agonist, which is in contrast to Win55212-2 that reduces cAMP as an agonist. JTE-907 dosed orally inhibited carrageenin-induced mouse paw edema dose dependently. The same in vivo effect was observed with other cannabinoid receptor ligands such as SR144528, Delta(9)-tetrahydrocannabinol (THC), and Win55212-2. This is the first report that a CB2-selective inverse agonist, JTE-907, has an anti-inflammatory effect in vivo, and how the inverse agonist showed the same effect as Win55212-2 and Delta(9)-THC is discussed.

Effects of intravenous anesthetic agents on pregnant myometrium

Emergent or elective surgical procedures under general anesthesia may be required during pregnancy for some patients. For this reason, effects of anesthetics on uterine contractions are important. General anesthesia is not limited to the administration of inhalation agents, since induction and maintenance of anesthesia usually involve intravenous administration of different anesthetic agents. The effects of these agents on uterine contractions and blood flow are very important. The unexpected relaxation or contraction of myometrium can be harmful to fetus and continuing pregnancy. Our aim in this study is to investigate the effects of intravenous anesthetic agents on uterine contractions. In our study, we examined the effects of ketamine, propofol and midazolam on contractions of isolated pregnant rat myometrium. We observed that exposure to propofol, ketamine and midazolam at the concentrations of 10(-5)-10(-4) M decreased spontaneous contractile activity in myometrial strips isolated from pregnant rats. There was statistically significant difference between the control and all strips exposed to propofol, ketamine and midazolam in the contraction amplitude and integrated area under the contraction curve.

Effects of endothelin-1 and calcium channel blockers on contractions in human myometrium. A study on myometrial strips from normal and diabetic pregnant women

OBJECTIVE

We studied the effect of endothelin (ET)-1 on spontaneous contractions and the effects of nimodipine and isradipine on ET-1-induced contractions in myometrial tissue from normal and diabetic pregnant women.

STUDY DESIGN

We isolated myometrial strips from seven normal pregnant and seven gestational diabetic women undergoing elective cesarean section at term. Three sets of experimental studies were performed with three myometrial strips obtained from every woman and mounted in organ baths for recording of isometric tension. In the first set, the effect of increasing concentrations of ET-1 (10(-11)-10(-8) M) on spontaneous contractions was recorded. In the second and third sets, effects of increasing concentration of nimodipine (10(-6)-3.10(-5) M) and isradipine (10(-5)-3.10(-4) M), respectively, on contractions following pretreatment with 10(-8) M ET-1 were recorded.

RESULTS

ET-1, beginning from 10(-9) M and 10(-10) M, significantly increased the amplitude of contractions in normal and diabetic strips, respectively. ET-1, beginning from 10(-9) M, also increased the frequency of contractions in normal and diabetic strips. The amplitude of contractions was significantly higher in diabetic strips as compared with normal strips at 10(-9) and 10(-8) M. There was no significant difference in the frequency of contractions between normal and diabetic strips. ET-1 at 10(-8) M also increased the basal tone of all normal and diabetic strips. Nimodipine, beginning from 10(-6) M and 3.10(-6) M, and isradipine, beginning from 10(-5) M and 3.10(-5) M, significantly decreased the amplitude of contractions in normal and diabetic strips, respectively. Nimodipine at 10(-5) M and 3.10(-5) M and isradipine at 3.10(-4) M significantly decreased the frequency of contractions in normal strips. Nimodipine, except at 3.10(-5) M, and isradipine did not significantly decrease the frequency of contractions in diabetic strips.

CONCLUSION

Gestational diabetes increases ET-1-induced contractile response in human myometrium. The contractile effect of ET-1 in normal and diabetic myometrium is mediated partly by dihydropyridine-sensitive calcium channels since it is significantly reduced by nimodipine and isradipine. The promising data from this study warrant clinical studies on the definitive place of nimodipine and isradipine in the treatment of preterm labor, especially in a diabetic woman, to avoid metabolic complications of beta-mimetic tocolytics.

Inhibitory effects of isradipine on spontaneous and oxytocin- and carbachol-stimulated contractions of rat myometrium

Our aim was to investigate the effect of isradipine, a second-generation calcium channel blocker, on spontaneous and oxytocin- and carbachol-stimulated contractions of myometrium isolated from nonpregnant and pregnant rats. Amplitude, frequency, duration and integrated area of spontaneous and oxytocin- and carbachol-stimulated contractions of nonpregnant and pregnant rat myometrium were compared before and after the treatment with isradipine (10(-6) to 10(-4) mol/l). Isradipine inhibited contractions of myometrial strips isolated from nonpregnant and pregnant rats in a concentration-dependent manner, with a significant effect on the amplitude (10(-5) to 10(-4) mol/l) and integrated area (3 x 10(-6) to 10(-4) mol/l) of spontaneous and oxytocin- and carbachol-stimulated contractions. Isradipine induced similar concentration-dependent effects on the frequency and duration of spontaneous and carbachol-stimulated contractions at higher concentrations (3 x 10(-5) to 10(-4) mol/l) but had no effect on frequency and duration of oxytocin-stimulated contractions. Isradipine appears to be an effective relaxant in rat myometrium. This effect of isradipine may become therapeutically advantageous in clinical application for preterm labor.

Effect of endothelin-1 on spontaneous contractions and effects of nimodipine and isradipine on endothelin-1-induced contractions in myometrial strips isolated from normal pregnant and preeclamptic women

BACKGROUND

To examine the effect of endothelin-1 (ET-1) on spontaneous contractile activity and the effects of nimodipine and isradipine on ET-1-induced contractile responses in myometrial strips isolated from normal pregnant and preeclamptic women.

MATERIAL AND METHODS

. Isolated myometrial strips were obtained from seven normal pregnant and seven preeclamptic women undergoing elective cesarean section and the strips were mounted in organ baths for recording of isometric tension. The effect of increasing concentration of ET-1 on spontaneous contractions and effects of increasing concentration of nimodipine and isradipine on ET-1-induced contractions were recorded.

RESULTS

ET-1 dose-dependently (10(-11)-10(-8) M) increased the amplitude and frequency of spontaneous contractions in all myometrial strips obtained from normal pregnant and preeclamptic women. The increase in the amplitude of contractions in preeclamptic strips was significantly higher than that of normal strips. The increase in amplitude of contractions in normal and preeclamptic strips reached statistical significance beginning from the concentrations of 10(-9) M and 10(-11) M, respectively. ET-1 (10(-8) M) also increased the basal tone of all myometrial strips isolated from normal pregnant and preeclamptic women. When ET-1 (10(-8) M)-contracted myoinetrial strips were exposed to increasing concentrations of nimodipine (10(-6)-3x10(-5)M) and isradipine (10(-5)-3x10(-4) M), nimodipine and isradipine dose-dependently decreased the amplitude and frequency of contractions.

CONCLUSIONS

The increase in contractile response with ET-1 was significantly higher in myometrial strips isolated from preeclamptic women compared to those of myometrial strips isolated from normal pregnant women. These increases in contractile response are at least in part mediated by dihydropyridine-sensitive calcium channels, since they were significantly reduced in the presence of increasing concentrations of nimodipine and isradipine.

Changes in the nitric oxide system of rat myometrium during midgestation and delivery at term

The aims of this study were to investigate whether a nitric oxide (NO) system is present in the pregnant rat myometrium and whether it differentially inhibits myometrial contractility during midgestation and delivery at term. Myometrial strips were obtained from eight rats at midgestation (day 16) and eight rats during delivery at term, and mounted in an organ bath for assessment of isometric tension. There were scarce spontaneous contractions with gradually increased amplitude that ceased after short periods at midgestation, whereas the frequency of spontaneous contractions increased and were regular, and the amplitude of contractions became stable and long lasting during delivery. Spontaneous and carbachol- induced contractions were decreased by L-arginine and increased by NG-nitro-L-arginine methyl ester (L-NAME) at midgestation and delivery, but much higher concentrations of L-arginine and L-NAME were required to obtain this effect at delivery. These results show: (1) that there is basal and carbachol-stimulated production of NO in pregnant rat myometrium; (2) that the L-arginine-NO system inhibits myometrial contractility; (3) that the effect of the L-arginine-NO system is elevated at midgestation and decreased during delivery; and (4) that the L-arginine-NO system may contribute to uterine quiescence during gestation and the initiation of labour at term.

Effects of nimodipine and isradipine on endothelin-1-induced contraction of pregnant rat myometrium

The purpose of this study was to investigate the effect of nimodipine and isradipine on endothelin-1-induced contractions of isolated pregnant rat myometrium. Endothelin-1 at 10(-10)-10(-8) M dose-dependently increased the amplitude and frequency of contractions and decreased the duration of contractions. Basal tone of myometrium was increased with the higher endothelin-1 concentrations (10(-9) and 10(-8) M). After pretreatment for 30 min with 10(-6) M nimodipine or 10(-5) M isradipine, amplitude and duration of endothelin-1-induced contractions were significantly decreased, but frequency of myometrial contractions increased markedly. However, neither agent abolished the stimulating effect of higher endothelin-1 concentrations (10(-9) and 10(-8) M) on the basal tone. Our study showed that phasic activity is inhibited by nimodipine and isradipine, whereas tonic activity is not inhibited. The contraction of myometrial strips isolated from the pregnant rat may be modulated by endothelin-1, and this effect is only partly modulated by dihydropyridine-type Ca2+ channels. The remaining resistance to nimodipine- and isradipine-induced inhibition may be explained by pregnancy-associated changes in the other electrophysiological and biochemical factors.

Effect of additional testosterone on purinergic responses in isolated rabbit corpus cavernosum strips

Recently, it has been demonstrated that the endothelium of corpus cavernosum (CC) plays an important role on smooth muscle relaxation, which is crucial to initiate and maintain erection. We investigated the effect of long-lasting additional testosterone propionate (TP) therapy on endothelium-dependent and -independent relaxations of isolated rabbit CC. Isolated CC strips were mounted in organ baths and isometric tension was recorded. Addition of a specific inhibitor of nitric oxide synthesis, NG-nitro-L-arginin methyl ester (L-NAME), into the organ bath had no effect on the relaxation responses to adenosine (ADO), adenosine 5'-triphosphate (ATP) and sodium nitroprusside (SNP) in isolated CC strips precontracted with phenylepherine, but completely inhibited relaxation responses produced by ADP. Adenosine and adenine nucleotides relaxed the phenylepherine-induced contractile response in control strips with the potency order: ADO (62.8 +/- 3.2%) > ATP (37.1 +/- 5.2%) > ADP (25.8 +/- 2.5%). The relaxation responses to ADO, ATP and SNP in isolated rabbit CC strips were not significantly altered by additional TP therapy. The relaxation responses produced by ADP were significantly enhanced following 1 and 2 months TP therapy as compared with controls. However, in the group treated with TP for 2 months followed by a 2 months drug-free period, relaxation responses were significantly reduced compared to 1 and 2 months treatment groups, and approached control values. Increased relaxation responses to ADP following 1 and 2 months additional TP therapy may be a result of increased endothelial purinergic receptor density, or it may be due to stimulation and/or release of endothelial nitric oxide (NO) by TP.

Effects of sympathectomy on endothelin-1 and histamine responses of rabbit carotid artery

1. The effects of chronic sympathectomy on contractile responses of rabbit common carotid artery was studied in vitro. 2. Endothelin-1 (ET-1), histamine, KC1 and papaverine concentration-response curves of sympathectomized and sham-operated (control) vessels were recorded and analyzed. Effects of endothelium removal also were investigated. 3. The contractions elicited by ET-1 and histamine in sympathectomized preparations did not change when compared with controls. Papaverine, which produces endothelium-independent relaxation, and KC1, which produces endothelium-independent contraction, did not differ from controls. No significant difference was observed between the contractile responses of sympathectomized vessels and those of control vessels to ET-1 and histamine after the removal of endothelium. 4. These results indicate that chronic sympathectomy did not affect the sensitivity to exogenous ET-1 and histamine of the vascular smooth muscle.

Effect of deferoxamine and sympathectomy on vasospasm following subarachnoid hemorrhage

We examined the effects of subarachnoid hemorrhage (SAH) and treatment with deferoxamine (DFO) or sympathectomy on vascular smooth muscle function, as well as the underlying mechanisms involved, by recording the responses to nor-adrenaline and serotonin in isolated carotid arteries in vitro. All studies were performed before and 7 days after SAH. An experimental subarachnoid hemorrhage model was created in rabbits by injecting autologous arterial blood into the subarachnoid space of the rabbits via cisterna magna punction. During the chronic stage of vasospasm following SAH deferoxamine (DFO) was given to the animals and cervical and periarterial sympathectomy was performed in the other groups of animals. In isolated carotid arteries noradrenaline (10(-8) to 10(-4) mol/l) and serotonin (10(-8) to 10(-4) mol/l) produced concentration-dependent contractions. These contractile responses were significantly enhanced in animals 7 days after SAH compared to controls and did not return to control values in carotid arteries obtained from animals treated with DFO or sympathectomy for 7 days after SAH. These results show that SAH causes supersensitivity in the carotid as well as cerebral arteries during the first week after SAH and could contribute to the development of cerebral vasospasm. Both treatment with DFO and sympathectomy after SAH did not reduce the contractile responses to noradrenaline and serotonin in the carotid arteries. In conclusion, treatment with DFO or sympathectomy during the chronic stage of vasospasm after SAH did not affect the vascular responses of the extradural part of the carotid artery to vasoactive substances.

Diagnostic value of renal arteriography in polyarteritis nodosa

Polyarteritis Nodosa (PAN) is a rare disease in childhood. No single pattern of clinical presentation characterizes this disease, but abdominal pain, central or peripheral nervous system disease, arthritis, myalgia and skin lesions occur at some time during the course of the illness. In this case a 16-year-old boy who presented with abdominal pain, elevated sedimentation rate associated with hypertension, and a high level of renin, all of which were detected during his hospitalization, suggested the diagnosis of PAN, and renal angiography was performed. Characteristic renal aneurysms were visualized and the diagnosis was confirmed.

Altered endothelium-mediated relaxation by sympathectomy in isolated rabbit carotid artery rings

The influence of cervical and periarterial sympathectomy on endothelium-dependent and endothelium-independent relaxations of the mature rabbit carotid artery was studied in vitro. The responses to adenosine, vasoactive intestinal polypeptide and substance P in sympathectomized and control rabbit carotid artery rings were recorded and analyzed. The effects of endothelium removal were also investigated. The maximal relaxation achieved by substance P, which produces endothelium-dependent relaxation, was significantly inhibited in 3 weeks in postsympathectomy arterial preparations as compared to controls. Adenosine and vasoactive intestinal polypeptide, which produce endothelium-independent relaxation, elicited similar relaxation in all tissues. These results demonstrated that the response to substance P was impaired by cervical and periarterial sympathectomy. The decreased maximum response to substance P may be the result of a decreased NK-1 receptor subtype density or excitation/response coupling, or it may be due to an impaired production and/or liberation of endothelium-derived relaxing factor (EDRF).

CT-guided pleural needle biopsy in the diagnosis of malignant mesothelioma

OBJECTIVE

Our goal was to determine the sensitivity of CT-guided closed pleural needle biopsy (CPNB) for the histopathologic diagnosis of diffuse malignant pleural mesothelioma (DMPM).

MATERIALS AND METHODS

Thirty patients with DMPM were studied with CT-guided CPNB. Tumor specimens were classified according to their cell types.

RESULTS

In 25 (83.3%) patients, the diagnosis was made by CT-guided CPNB. The remaining five patients were diagnosed by thoracoscopy, thoracotomy, or excisional biopsy of the chest wall mass. Pneumothorax was observed in 9.5% of patients and local seeding of tumor in 21.7% of patients who underwent CPNB.

CONCLUSION

Properly performed CPNB under CT guidance may yield an increased sensitivity for the diagnosis of diffuse malignant pleural mesothelioma.

Effects of propofol on vascular smooth muscle function in isolated rat aorta

This study was undertaken to determine the direct actions of propofol, and whether propofol exerts any action on basal endothelium-derived relaxing factor release and vasodilator effect of acetylcholine on phenylephrine-induced contractile responses in isolated rat aortic rings. This compound is known to produce a fall in blood pressure in man and animals, and it has been suggested that the hypotension may result from a direct vasodilator action on the veins and arterioles. In this study, propofol did not induce any contractile response in aortic rings at various concentrations (10(-8)-10(-4) M). Propofol did not significantly alter phenylephrine-induced contractions at lower concentrations (10(-8)-10(-6) M) but at higher concentrations (10(-5)-10(-4) M) the depression caused by propofol was significant in both endothelium-intact and -denuded rings. Pretreatment of the endothelium-intact rings with propofol (10(-6) and 10(-5) M) produced a reduction in the relaxant effect of acetylcholine. The results obtained in this study demonstrate that clinically relevant concentrations of propofol (10(-6) M or less) have no direct vasodilator effects and that it reduces endothelium-dependent relaxation to acetylcholine.

Cerebral hydatid cysts: CT findings

The CT features of cerebral hydatid cysts are divided into two groups. In the unilocular cases, the cyst is large, spherical in shape with sharply defined borders. One side of the cyst wall is very close to the calvarium. The cyst may calcify and may have septae inside. There is no enhancement with contrast media and also no edema surrounding the cyst. In the second group there are multiple and small multilocular cysts. These cysts are in ovoid or polygonal forms like a bunch of grapes, with perifocal edema. After contrast media administration, there is enhancement in the cyst wall. In one case there were numerous cysts in both hemispheres.

Purification and properties of alpha-mannosidase from bakers' yeast

The yeast alpha-mannosidase [EC 3.2.1.24] was purified 1160-fold from the crude extract of the autolysate. The purified preparation was practically free from alpha-glucosidase, beta-glucosidase, alpha-galactosidase, beta-galactosidase, beta-mannosidase, and beta-N-acetylhexosaminidase activities. After the separation of yeast mannan during the purification procedures the enzyme became unstable but could be stored at 5 degrees C for three weeks with 50% loss of activity. The purified enzyme hydrolyzed both aryl and alkyl mannosides, but hydrolysis of yeast mannan proceeded slowly. Yeast mannan and Zn2+ increased the enzyme catalyzed hydrolysis of p-nitrophenyl mannoside, whereas NaN3, monoiodoacetate and methyl alpha-D-mannoside acted as inhibitors. The molecular weight was estimated to be 450,000 by gel filtration.