Practical use of the central venous access port for contrast-enhanced CT: comparison with peripheral intravenous access regarding enhancement and safety.

AIM: To evaluate the efficacy of using the central venous (CV) port compared with peripheral intravenous access for contrast-material injection for contrast enhancement during the portal venous phase. MATERIALS AND METHODS: Patients were divided into three groups: CV delay, CV routine, and peripheral access (PA) groups. Patients in the CV delay group underwent injection in the arm-down position with an additional delay, while those in the CV routine and PA groups underwent injections with the routine injection protocol for portal venous phase imaging. Contrast enhancement was evaluated by measuring the mean radiodensity (Hounsfield units) values for the aortic arch, abdominal aorta, inferior vena cava, portal vein, and spleen. The peak injection pressure was recorded and compared among the three groups. RESULTS: No complications related to power injection were observed during 119 contrast-material injections performed using the CV port device. The CV delay group showed significantly lower radiodensity values than the PA group (165.7 ± 20.1 versus 181 ± 19 HU [p<0.01] for the portal vein); however, no significant differences in mean radiodensity values were observed between the CV routine and PA groups (p>0.05). The median peak injection pressure was 73.5, 67, and 47 psi in the CV delay, CV routine, and PA groups, respectively (p<0.01). CONCLUSION: The CV port can be used for safe contrast-material injection while maintaining contrast enhancement on portal venous phase comparable to that achieved with peripheral intravenous access.

Magnetic structure of the noncentrosymmetric magnet Sr2MnSi2O7 through irreducible representation and magnetic space group analyses.

Magnetic structures of the noncentrosymmetric magnet Sr2MnSi2O7 were examined through neutron diffraction for powder and single-crystalline samples, as well as magnetometry measurements. All allowed magnetic structures for space group P421m with the magnetic wavevector qm = (0, 0, ½) were refined via irreducible representation and magnetic space group analyses. The compound was refined to have in-plane magnetic moments within the magnetic space group Cmc21.1'c (No. 36.177) under zero field, which can be altered to P212121.1'c (No. 19.28) above µ0H = 0.067 (5) T to align induced weak-ferromagnetic components within one layer on the ab plane. All refined parameters are provided following the recent framework based upon the magnetic space group, which better conveys when exchanging crystallographic information for commensurate magnetic structures.

Adenosine and adenosine uptake inhibitors potentiate the neuromuscular blocking action of rocuronium mediated by adenosine A(1) receptors in isolated rat diaphragms.

BACKGROUND: Adenosine, which pre-junctionally modulates neuromuscular transmission, and adenosine uptake inhibitors, which increase extracellular adenosine, have been used clinically. We investigated the effects of adenosine, dipyridamole and midazolam on the neuromuscular blocking action of rocuronium. METHODS: Isometric twitch tensions of rat nerve-hemidiaphragm preparations elicited by indirect (phrenic nerve) supra-maximal stimulation at 0.1 Hz were evaluated (n=6 in all data). RESULTS: Pre-treatments with adenosine (0.1 and 1 microM) and CCPA (1 microM, adenosine A(1) receptor agonist), but not that with CGS21680 (0.5 microM, A(2) receptor agonist), shifted the rocuronium concentration-twitch tension curves to the left and decreased the rocuronium concentration for 50% twitch depression (IC(50)) compared with the control (P<0.01). The leftward shift induced by 1 microM adenosine was inhibited by pre-treatments with theophylline (50 microM, non-selective adenosine receptor antagonist) and DPCPX (0.2 microM, A(1) receptor antagonist) but not by that with DPMA (5 microM, A(2) receptor antagonist). Pre-treatments with dipyridamole and midazolam, adenosine uptake inhibitors, shifted the curve to the left and decreased IC(50) at supra-therapeutic concentrations (10 and 2.5 microM, respectively) but not at clinical concentrations (2 and 0.5 microM, respectively), and the leftward shifts were inhibited by pre-treatment with DPCPX (0.2 microM). CONCLUSION: The results indicate that adenosine potentiates the neuromuscular blocking action of rocuronium mediated by adenosine A(1) receptors and that supra-therapeutic concentrations of dipyridamole and midazolam also potentiate the action of rocuronium by increasing endogenous adenosine concentration.

5,6-Dichloro-1-methylgramine, a non-toxic antifoulant derived from a marine natural product.

The laboratory culture of the barnacle, Balanus amphitrite has made it possible to supply cypris larvae for antifouling assays all year round. The settlement of cyprids obtained from cultured B. amphitrite was indistinguishable from cyprids reared from field-collected barnacles. In laboratory cyprid settlement assays of extracts from marine sessile organisms, antifouling activity was expressed as the 99% inhibitory concentration (IC99), and toxicity as the 30% lethal concentration (LC30). The lipophilic extract of the marine bryozoan, Zoobotryon pellucidum, which showed promising antifouling activity, yielded 2,5,6-tribromo-1-methylgramine (TBG) by bioassay-guided isolation. The inhibitory activity of TBG was 6 times as strong as that of bis-(n-butyltin)oxide (TBTO), while its toxicity to cypris larvae was one-tenth that of TBTO. A structure-activity relationship study with 155 indole derivatives led to the discovery of the non-toxic antifoulant candidates 5,6-dichlorogramine, 5-chloro-2-methylgramine, and 5,6-dichrolo-1-methylgramine (DCMG), the latter being selected as the antifouling paint ingredient for performance evaluation tests (panel tests) following the results of a preliminary safety tests. A silicone-based antifouling paint containing 5-10% of DCMG was prepared and tested in the field; the painted surfaces remained almost barnacle-free for 1.5 years similar to silicone coatings such as Biox. Since the leaching rate of DCMG from the paint surface could be controlled by the addition of an acrylic acid-styrene copolymer (ASP), the life of the antifouling performance is expected to be improved. Thus, an extremely non-toxic silicone-based antifouling paint containing DCMG is under development.

Temperature-dependent change of serological specificity of Candida albicans NIH A-207 cells cultured in yeast extract-added Sabouraud liquid medium: disappearance of surface antigenic factors 4, 5, and 6 at high temperature.

The cells of Candida albicans NIH A-207 strain (A-strain) cultivated in YSLM at high temperatures (37 and 40 degrees C) did not undergo agglutination with the factor sera 4, 5, and 6 in a commercially available factor serum kit, 'Candida Check', and formed a grape-like shape. The mannans isolated from the cells had lost their reactivity against the factor sera in ELISA. It was also revealed by 1H NMR analysis that the mannans contained neither a phosphate group nor a beta-1,2-linked mannopyranose unit, although these mannans increased the non-reducing terminal alpha-1,3-linked mannopyranose unit. The cells and the mannans prepared by cultivation at such high temperatures followed by 27 degrees C in the same medium entirely recovered the reactivity with the factor sera.

Central venous catheter migration to the popliteal artery during total cavopulmonary shunt.

Central venous catheter migration to the arterial system occurred due to the surgical procedure during total cavopulmonary shunt. The catheter seems to have crept into the portion of the vena cava that had been designated for clamping, because of the position for the surgery and the anatomic characteristics of the patient. The catheter migrated in the right popliteal artery and was removed immediately; however, it could enter the pulmonary arterial system and the other systemic arterial branches.

Acute pulmonary edema associated with transfusion of packed red blood cells.

We experienced a patient who suffered noncardiogenic acute pulmonary edema after transfusion of packed red blood cells which contained antigranulocyte antibodies. The data suggested that complement activation and the release of polymorphonuclear protease were involved in the pathogenesis of the complication in the present patient. Furthermore, blood coagulative system was also activated after the transfusion. The underlying mechanisms of the complication are discussed.

Involvement of capsaicin-sensitive fibers in spinal NMDA-induced glutamate release.

The activation of spinal NMDA receptors can evoke glutamate release through the production of nitric oxide (NO) within the spinal cord, resulting in pain-relating behavior. In this study, we investigated the involvement of capsaicin-sensitive primary afferents in this phenomenon using in vivo intrathecal microdialysis. Intrathecal NMDA perfusion evoked increases in the concentrations of NO metabolises and glutamate and in pain-related behavior in both neonatal capsaicin and vehicle-treated rats. Although the degrees of increase in NO metabolises in capsaicin- and vehicle-treated rats were not significantly different, capsaicin-treated rats showed significantly smaller increases in glutamate concentration and pain-related behavior than did vehicle-treated rats. Our results showed that glutamate release from capsaicin-sensitive primary afferent terminals is involved in spinal NMDA-induced pain.

Formalin-induced nociception activates a monoaminergic descending inhibitory system.

Neural plasticity of afferent pain pathways that is induced by prolonged or repeated noxious stimuli may contribute to activate intrinsic inhibitory mechanisms in CNS. In order to clarify the role of the monoaminergic descending inhibitory system in acute nociception and inflammatory pain, we examined if this inhibitory system would modulate the tonic response to formalin-induced nociception. Yohimbine, alpha2 adrenergic antagonist, or methysergide, serotonin antagonist was administered intrathecally before or after subcutaneous 2% formalin injection into the plantar of the hind paw in rats. In another series of the experiment, the tissue of the spinal dorsal half of the untreated rats and post-formalin-treated rats were sampled and analyses of monoamine levels were carried out by HPLC. The subcutaneous formalin evoked biphasic flinching behavior of the injected paw. Intrathecal pretreatment with yohimbine and methysergide produced a significantly greater increase in the number of flinches than in the control in phase 1, intermediate period and phase 2. Posttreatment with yohimbine and methysergide showed a significantly greater increase in the number of flinches in phase 2. Furthermore, formalin injection induced significant increases in noradrenaline, MHPG, serotonin (5-hydroxytryptamine; 5-HT) and 5-HIAA concentrations in both the ipsi- and contralateral dorsal halves. These results suggest that the pain state produced by formalin-induced chemical and/or inflammatory nociception is under the modulation of the monoaminergic (noradrenergic and serotonergic) descending inhibitory system.

Formalin-induced release of excitatory amino acids in the skin of the rat hindpaw.

Application of glutamate to skin evokes pain-related behaviors [S.M. Carlton, G.L. Hargett, R.E. Coggeshall, Localization and activation of glutamate receptors in unmyelinated axons of rat glabrous skin, Neurosci. Lett., 197 (1995) 25-28; D.L. Jackson, C.B. Graff, J.D. Richardson, K.M. Hargreaves, Glutamate participates in the peripheral modulation of thermal hyperalgesia in rats, Eur. J. Pharmacol., 284 (1995) 321-325.] and peripherally-administered glutamate antagonists can prevent the nociception produced by inflammation [E.M. Davidson, R.E. Coggeshall, S.M. Carlton, Peripheral NMDA and non-NMDA glutamate receptors contribute to nociceptive behaviors in the rat formalin test, NeuroReport, 8 (1997) 941-946; Jackson et al., 1995.] In this study, the concentrations of glutamate and aspartate in the plantar of the rat hindpaws were measured before and after the subcutaneous administration of formalin. Increases in glutamate and aspartate concentrations were observed on the ipsilateral side, but not on the contralateral side, to the injection. This shows that nociception and inflammation caused by formalin injection induces the release of peripheral glutamate and aspartate, which would contribute to nociception and inflammatory pain.

Peripheral nitric oxide in carrageenan-induced inflammation.

Recent studies have suggested that nitric oxide (NO) peripherally produced by different nitric oxide synthase (NOS) isoforms contributes to edema formation and development of hyperalgesia. The present study was designed to examine the effects of NOS isoforms on NO release in carrageenan-induced inflammation at various time points. A microdialysis probe was implanted subcutaneously into the glabrous skin of hindpaws of Sprague-Dawley rats under pentobarbital anesthesia. After sample collection to obtain the basal level of the total amount of nitrite and nitrate (NO2-/NO3-), modified Ringer solution, a non-selective NOS inhibitor, NG monomethyl-L-arginine acetate (L-NMMA), or an iNOS inhibitor, aminoguanidine hemisulfate (AG) was perfused through the microdialysis probe. 2 mg of carrageenan was injected into the plantar surface of the probe-implanted hindpaw. Carrageenan was also injected in rats that had undergone sciatic nerve sectioning. Carrageenan significantly increased the dialysate concentrations of NO2-/NO3- for more than 8 h. L-NMMA suppressed the carrageenan-induced increase in NO2-/NO3- concentration. Although AG did not suppress the increase in NO2-/NO3- for the first 2 h after carrageenan injection, significant suppression of the increase in NO2-/NO3- was observed from 2.5 h after carrageenan injection. In the rats in which the sciatic nerves had been denervated, the increases in concentrations of NO2-/NO3- were completely suppressed up to 3 h and partially suppressed 4.5-8 h after carrageenan injection. The results of the current study show that carrageenan induces peripheral release of NO, the production of which is mediated by nNOS in the early phase and by both nNOS and iNOS in the late phase of carrageenan-induced inflammation.

Aneurysms associated with fenestrated anterior cerebral arteries. Report of four cases and review of the literature.

Four cases of aneurysms associated with a fenestrated anterior cerebral artery are presented. The combination of aneurysms and fenestration of the anterior cerebral artery is rare, and nine cases including ours have been reported. In all cases fenestrations were found within the distal two-thirds of the horizontal portion of the anterior cerebral artery. It may be presumed that fenestration of the anterior cerebral artery is the remnant of the plexiform anastomosis in the fetal stage, especially between the anterior cerebral artery and the primitive olfactory artery.

Relationships between the number of small follicles prior to superovulatory treatment and superovulatory response in Holstein cows.

In order to determine relationships between the number of small follicles prior to superovulatory treatment and superovulatory response, a total of 55 superovulations were induced in Holstein cows. The ovaries were examined ultrasonographically once 0-1.5 days before the initiation of superovulatory treatment. The number of small follicles 3-6 mm in diameter on both ovaries before superovulatory treatment was found to be significantly correlated with the numbers of corpora lutea after superovulation (r = 0.440, P < 0.001), total ova recovered (r = 0.503, P < 0.001) and transferable embryos recovered (r = 0.482, P < 0.001). These results indicate that a single ultrasonographic examination of follicles 3-6 mm in diameter prior to superovulatory treatment can be utilized to predict superovulatory response.

[A case of brain metastasis of rhabdomyosarcoma in a child].

We report here a specific case of metastatic brain tumor orienting from rhabdomyosarcoma. An 11-year-old boy came to our hospital with complaints including headache, exophthalmos and tumors in the right frontal and left occipital region. 6 months previously subtotal removal of rhabdomyosarcoma in his right foot had been performed. CT scan demonstrated tumors in the right orbit, right frontal region and left occipital region. The tumors existed bilaterally in the skull and markedly enhanced by contrast medium. But the changes of the cranium were mild, only the dipole was slightly dilated. MRI showed that the tumors were extraaxial masses. Right external carotid angiogram revealed numerous tumor vessels fed by the meningeal artery. On April 3rd, biopsy was performed at the right frontal region. The tumor had spread in the epidural space but the cortical surface seemed to be intact. Histologically, the tumor consisted of small round cells and revealed multinuclear giant cells. It involved the skull bone, dura mater and subdural tissues. Accordingly the tumor was diagnosed as rhabdomyosarcoma. Although tumor increased rapidly, the intracranial region did not change remarkably. It was an interesting phenomenon. Eventually, rhabdomyosarcoma metastasized to the lung, and the patient died due to respiratory distress.

[Anesthesia for tricuspid valve replacement after heart transplantation].

A 41 year old male patient had received heart transplantation in U.S. in 1993. When myocardial biopsy was performed in 1998, tendinous cords of the tricuspid valve were injured. Tricuspid regurgitation developed along with right heart insufficiency, and the patient was scheduled for tricuspid replacement. For induction of anesthesia, midazolam and fentanyl were used. After induction, both blood pressure and pulse rate were stable. During extracorporeal circulation, perfusion pressure was controlled at 70-80 mmHg, and the duration of cardio-pulmonary perfusion was about 90 minutes. For withdrawal from extracorporeal circulation, dopamine and dobutamine were used. The course was steady and normal after the withdrawal. In tricuspid valve replacement after heart transplantation, stabilized anesthetic course could be maintained using midazolam and fentanyl.

[An unusual cause of anesthetic ventilator malfunction].

We report a case of malfunction of an anesthetic ventilator by an unusual cause. A 48-year-old male with gastric cancer was scheduled for gastrectomy. Anesthesia was maintained with enflurane, N2O, O2 and epidural blockade using a semiclosed circuit system. The patient was ventilated using AV1 anesthetic machine (Dräger Co.). Forty minutes after induction of anesthesia, chest movement of the patient suddenly stopped. There was no gas flow to the patient during inspiratory phase. Air leak was not found in anesthetic respiratory circuit and at the bellows of the ventilator. The supply of oxygen and air to the anesthetic machine was sufficient. Since we could not find any cause of the ventilator failure, anesthesia was maintained with manual ventilation by using another anesthetic machine until completion of the surgery. After the surgery, we recognized that the controller unit of expiratory valve of the ventilator was obstructed by a Tamper Proof Film, which seals the outlet of a commercial bag of lactated Ringer's solution (Solulact, Terumo Co.). It seems that the film dropped accidentally between the main part and the ventilator system of anesthetic machine when the bellows was exchanged before the surgery, and moved on to the controller unit of the expiratory valve of the ventilatory system during surgery. In conclusion, it is necessary for anesthetists to understand the inner structure and system of the anesthetic machine and to check the anesthetic machine to avoid the troubles and accidents related to anesthetic machine.

[Continuous thoracic epidural blockade in combination with general anesthesia with nitrous oxide, oxygen, and sevoflurane in two patients with myasthenia gravis].

Continuous thoracic epidural anesthesia (T4/5) using 4-5 ml.h-1 of 1.5% lidocaine with 1:200,000 epinephrine and inhaled anesthesia using nitrous oxide, oxygen and sevoflurane were performed in two patients, (40 and 22 yr-old females) with myasthenia gravis. This combined anesthetic technique provided muscle relaxation for endotracheal intubation and optimal operating conditions, including muscle relaxation and stability of hemodynamics during transsternal thymectomy. Further, continuous epidural anesthesia using 4 ml.h-1 of 0.25% bupivacaine provided postoperative pain relief without other analgesics and stable postoperative respiratory conditions. In conclusion, we confirm the benefits of this technique which provides not only safe and stable conditions during the surgery, but also an improved comfort for patients in the postoperative period following transsternal thymectomy for myasthenia gravis.

[Evaluation of analgesic effects of morphine, buprenorphine and pentazocine in rats receiving somatic and visceral stimulation].

The analgesic effects of morphine, buprenorphine and pentazocine examined by behavioral responses to tail-flick (TF) and colorectal distension (CD) were studied in rats. Animals were randomly divided into three groups; morphine (M) groups of 4 mg.kg-1 (n = 7), buprenorphine (B) groups of 0.03 mg.kg-1 (n = 8), pentazocine (P) groups of 3 mg.kg-1 (n = 8). After determinations of TF and CD values, animals were administered each analgesic intraperitoneally, and both procedures were repeated every 5 minutes until 40 minutes. Three drugs produced an almost same degree of increase in pain threshold for TF; % maximum possible effects (%MPEs) were approximately 30%. Similar patterns of increase in pain thresholds for CD were observed in M and B groups; %MPEs were approximately 20%. In contrast, P groups showed a significant increase in thresholds for CD compared to M and B groups; 20 minutes after intraperitoneal administration of P, %MPE was approximately 50%. These results indicate that there are different antinociceptive effects to somatic and visceral stimuli between M, B and P, and suggest that selective opioid agonists modulate responses to different kinds of noxious stimuli.

[Interpleural administration of 1.0% and 1.5% lidocaine with epinephrine for pain relief after thoracotomy].

Pain relief following thoracotomy and arterial concentration profiles after interpleural administration of lidocaine were studied in 23 adult patients. They were allocated to three groups and given interpleural injection of 20 ml each of 1.0% (group 1, N = 9, non-pneumonectomy patients), 1.5% (group 2, N = 10, non-pneumonectomy patients), and 1.5% (group 3, N = 4, pneumonectomy patients) lidocaine with epinephrine (5 micrograms.ml-1). Complete pain relief was obtained within 20 min after injection in all patients. The mean duration of analgesia was 2.8 hr, 3.1 hr, and 5.1 hr in group 1, 2, and 3, respectively. The maximum plasma concentrations of lidocaine (Cmax) were 1.7 +/- 1.0 (mean +/- SD) microgram.ml-1, 2.2 +/- 0.6 micrograms.ml-1, and 0.7 +/- 0.2 micrograms.ml-1 in group 1, 2, and 3, respectively. The mean duration of analgesia was significantly longer in group 3 than in group 2 (P less than 0.01). Cmax was significantly lower in group 3 than in group 2 (P less than 0.01). In conclusion, we consider interpleural injection of lidocaine with epinephrine to be an effective method of providing postoperative analgesia after thoracotomy. Our data also suggest that the duration of analgesia may increase and the plasma levels of lidocaine may remain quite low in total pneumonectomy patients, because local anesthetic solution is not absorbed through the visceral pleura but absorbed only through the parietal pleura alone in these patients.

[Effect of preoperative treatment with recombinant human erythropoietin in patients undergoing hemodilutional autologous transfusion].

This study evaluated whether a combination of recombinant human erythropoietin (rHuEPO) and hemodilutional autologous transfusion could reduce homologous blood transfusion in 37 patients who underwent elective urological surgery. A single dose of 6000 IU rHuEPO was administered 2 weeks before operation to patients whose preoperative hemoglobin was less than 12.0 g.dl-1 (8.5-12.0 g.dl-1) (EPO group, n = 15) and compared these with control subjects whose preoperative hemoglobin was more than 12.0 g.dl-1 (non-EPO group, n = 22). Both hemoglobin and hematocrit levels after administration of rHuEPO in the EPO group increased significantly to the same levels as in those in the non-EPO group and remained at these levels. The mean volume of donated autologous blood was 980 g in the EPO group and 110 g in the non-EPO group. The mean surgical blood loss was 1330 g in the EPO group and 1120 g in the non-EPO group. No homologous blood transfusion was required in 80 percent of the cases in both groups: however, homologous transfusions were added to 3 cases in the EPO group and 4 cases in the non-EPO group whose surgical blood loss was over 2500 g. We conclude that the combination of preoperative rHuEPO treatment and hemodilutional autologous transfusion can reduce homologous transfusion during surgery in anemic patients.