Liquid Structure of Tantalum under Internal Negative Pressure

In situ femtosecond x-ray diffraction measurements and ab initio molecular dynamics simulations were performed to study the liquid structure of tantalum shock released from several hundred gigapascals (GPa) on the nanosecond timescale. The results show that the internal negative pressure applied to the liquid tantalum reached -5.6 (0.8)  GPa, suggesting the existence of a liquid-gas mixing state due to cavitation. This is the first direct evidence to prove the classical nucleation theory which predicts that liquids with high surface tension can support GPa regime tensile stress.

Structural change in liquid sulphur from chain polymeric liquid to atomic simple liquid under high pressure

The structural properties of liquid sulphur under high pressure up to approximately 500 GPa have been investigated by means of ab initio molecular-dynamics (MD) simulations. The obtained pair distribution functions and spatial distribution of electron density under high pressure indicate the existence of a covalent-like interaction even in the metallic state and the covalent-like interaction gradually decreases with increasing pressure. By analyzing the static structure factor, it is found that the covalent-like interaction still remains at approximately 200 GPa, and liquid sulphur has a simple liquid structure at 320 GPa and higher pressures. These results indicate that the covalent-like interaction disappears at a pressure between 200 and 320 GPa. In this study, we also estimate the pressure range of structural change in other liquid chalcogens in a similar manner as liquid S. The pressures at which liquid Se and Te have simple liquid structure are estimated to be larger than approximately 100 and 20 GPa, respectively.

Dissociation dynamics of ethylene molecules on a Ni cluster using ab initio molecular dynamics simulations

The atomistic mechanism of dissociative adsorption of ethylene molecules on a Ni cluster is investigated by ab initio molecular-dynamics simulations. The activation free energy to dehydrogenate an ethylene molecule on the Ni cluster and the corresponding reaction rate is estimated. A remarkable finding is that the adsorption energy of ethylene molecules on the Ni cluster is considerably larger than the activation free energy, which explains why the actual reaction rate is faster than the value estimated based on only the activation free energy. It is also found from the dynamic simulations that hydrogen molecules and an ethane molecule are formed from the dissociated hydrogen atoms, whereas some exist as single atoms on the surface or in the interior of the Ni cluster. On the other hand, the dissociation of the C-C bonds of ethylene molecules is not observed. On the basis of these simulation results, the nature of the initial stage of carbon nanotube growth is discussed.

Femtosecond charge and molecular dynamics of I-containing organic molecules induced by intense X-ray free-electron laser pulses

We studied the electronic and nuclear dynamics of I-containing organic molecules induced by intense hard X-ray pulses at the XFEL facility SACLA in Japan. The interaction with the intense XFEL pulse causes absorption of multiple X-ray photons by the iodine atom, which results in the creation of many electronic vacancies (positive charges) via the sequential electronic relaxation in the iodine, followed by intramolecular charge redistribution. In a previous study we investigated the subsequent fragmentation by Coulomb explosion of the simplest I-substituted hydrocarbon, iodomethane (CH₃I). We carried out three-dimensional momentum correlation measurements of the atomic ions created via Coulomb explosion of the molecule and found that a classical Coulomb explosion model including charge evolution (CCE-CE model), which accounts for the concerted dynamics of nuclear motion and charge creation/charge redistribution, reproduces well the observed momentum correlation maps of fragment ions emitted after XFEL irradiation. Then we extended the study to 5-iodouracil (C₄H₃IN₂O₂, 5-IU), which is a more complex molecule of biological relevance, and confirmed that, in both CH₃I and 5-IU, the charge build-up takes about 10 fs, while the charge is redistributed among atoms within only a few fs. We also adopted a self-consistent charge density-functional based tight-binding (SCC-DFTB) method to treat the fragmentations of highly charged 5-IU ions created by XFEL pulses. Our SCC-DFTB modeling reproduces well the experimental and CCE-CE results. We have also investigated the influence of the nuclear dynamics on the charge redistribution (charge transfer) using nonadiabatic quantum-mechanical molecular dynamics (NAQMD) simulation. The time scale of the charge transfer from the iodine atomic site to the uracil ring induced by nuclear motion turned out to be only ∼5 fs, indicating that, besides the molecular Auger decay in which molecular orbitals delocalized over the iodine site and the uracil ring are involved, the nuclear dynamics also play a role for ultrafast charge redistribution. The present study illustrates that the CCE-CE model as well as the SCC-DFTB method can be used for reconstructing the positions of atoms in motion, in combination with the momentum correlation measurement of the atomic ions created via XFEL-induced Coulomb explosion of molecules.

Detection of monoclonality in intestinal lymphoma with polymerase chain reaction for antigen receptor gene rearrangement analysis to differentiate from enteritis in dogs

The diagnosis of canine intestinal lymphoma by morphological examination is challenging, especially when endoscopic tissue specimens are used. The utility of detection of antigen receptor gene rearrangement by polymerase chain reaction (PARR) in canine lymphoma has been well established, but its usefulness to distinguish enteritis and intestinal lymphoma remains unclear. In this retrospective study we assessed clonality of 29 primary canine intestinal lymphoma, 14 enteritis and 15 healthy control cases by PARR analysis, using formalin-fixed, paraffin-embedded full-thickness tissue specimens. We could detect monoclonal rearrangements in 22 of 29 canine intestinal lymphomas [76%; 95% confidence interval (CI) 56-90%] and polyclonal rearrangements in all of the enteritis and healthy control cases (100%; CI 88-100%). We revealed a predominance of T-cell phenotype compared to B-cell phenotype (85%; CI 65-96% and 15%; CI 4-35%, respectively). We showed that PARR analysis contributes to differentiation of canine intestinal lymphoma from enteritis and to phenotyping of lymphomas.

A novel function of extraerythrocytic hemoglobin: identification of globin as a stimulant of plasminogen activator biosynthesis in human fibroblasts

Following wounding, the surrounding fibroblasts migrate towards the clotted blood in the wounded space to form granulation tissue resulting in wound repair. One of the most abundant proteins in the wound is hemoglobin (Hb). The aim of the present study was to examine the effect of Hb on fibroblasts in producing components of the plasminogen-plasmin system which play an important role in wound healing. Human Hb A0 added to cultures of human fibroblasts elicited a dose-dependent increase in fibrinolytic activity. ELISA demonstrated an increased fibrinolytic activity due to increased urokinase-type plasminogen activator (uPA). An increase in tissue-type PA was also detected, while the type-I PA inhibitor level remained unaffected. Globin showed a similar effect, while hemin and protoporphyrin IX exerted no effect. The influence of Hb was quenched when haptoglobin was added. Although northern blot analysis revealed no difference in uPA transcripts between stimulated and non-stimulated cells, immunoprecipitation experiments confirmed an increased uPA synthesis in Hb- and globin-treated cells, suggesting that enhanced expression is achieved through translational regulation. These findings suggest a potential role for globin in modulating cellular functions during the process of wound healing.

Systemic toxicity and resuscitation in bupivacaine-, levobupivacaine-, or ropivacaine-infused rats

We compared the systemic toxicity of bupivacaine, levobupivacaine, and ropivacaine in anesthetized rats. We also compared the ability to resuscitate rats after lethal doses of these local anesthetics. Bupivacaine, levobupivacaine, or ropivacaine was infused at a rate of 2 mg. kg(-1). min(-1) while electrocardiogram, electroencephalogram, and arterial pressure were continuously monitored. When asystole was recorded, drug infusion was stopped and a resuscitation sequence was begun. Epinephrine 0.01 mg/kg was administered at 1-min intervals while external cardiac compressions were applied. Resuscitation was considered successful when a systolic arterial pressure > or =100 mm Hg was achieved within 5 min. The cumulative doses of levobupivacaine and ropivacaine that produced seizures were similar and were larger than those of bupivacaine. The cumulative doses of levobupivacaine that produced dysrhythmias and asystole were smaller than the corresponding doses of ropivacaine, but they were larger than those of bupivacaine. The number of successful resuscitations did not differ among groups. However, a smaller dose of epinephrine was required in the Ropivacaine group than in the other groups. We conclude that the systemic toxicity of levobupivacaine is intermediate between that of ropivacaine and bupivacaine when administered at the same rate and that ropivacaine-induced cardiac arrest appears to be more susceptible to treatment than that induced by bupivacaine or levobupivacaine.

Aerosolized surfactant therapy for endotoxin-induced experimental acute respiratory distress syndrome in rats

We have compared the effects of inhalation of aerosolized surfactant on experimental acute respiratory distress syndrome. Escherichia coli endotoxin (55 (SD 20) mg kg(-1)) was injected into the tracheas of 36 adult rats anaesthetized and mechanically ventilated with pure oxygen. When the Pa(O(2)) decreased to 11.3 (3.3) kPa, the animals were randomly subjected to inhalation of aerosolized modified natural surfactant (MNS) for 0 min (control group), 30, 60, and 120 min. In the control group, Pa(O(2)) remained below 12 kPa for 180 min. In the groups receiving inhalation of surfactant for 30 and 60 min, Pa(O(2)) increased but decreased soon after termination of the inhalation. In contrast, Pa(O(2)) of the group receiving inhalation of surfactant for 120 min continued to increase, reaching 52.1 (12.5) kPa at 180 min (P<0.05 vs control). Thus, we conclude that improvement in gas exchange as a result of inhalation of MNS depends on the duration of inhalation.

Does hyperthermia induce peritoneal damage in continuous hyperthermic peritoneal perfusion?

To investigate the mechanisms of the peritoneal damage induced by continuous hyperthermic peritoneal perfusion (CHPP), protein and fluid loss during and after CHPP and continuous normothermic peritoneal perfusion (CNPP) was studied. Sixteen patients with advanced gastric cancer underwent peritoneal perfusion therapy with saline solution containing 150 to 300 mg cisplatin and 30 to 60 mg mitomycin C for 60 minutes. The temperature in Douglas' pouch was maintained at 42.0 degrees C in the CHPP group (n = 9) and 37.0 degrees C in the CNPP group (n = 7) during perfusion. No statistical differences were found in patients' characteristics between the groups except the maximum temperature in Douglas' pouch during perfusion (41.6 degrees +/- 0.4 degrees C and 37.6 degrees +/- 0.4 degrees C in CHPP and CNPP groups, respectively, p < 0.05). The amount of protein lost into the perfusate was 0.35 +/- 0.22 g/kg body weight in the CHPP group and 0.37 +/- 0.19 g/kg in the CNPP group, showing no significant difference. On the day of surgery, there was no significant difference in the amount of protein and fluid lost through the abdominal drains between the CHPP group (27.9 +/- 24.6 mg/kg/hr and 0.94 +/- 0.63 ml/kg/hr, respectively) and the CNPP group (25.9 +/- 8.6 mg/kg/hr and 1.03 +/- 0.31 ml/kg/hr, respectively). We could not find any significant differences in postoperative protein and fluid loss between the groups on the following 3 days either. We conclude that the peritoneal damage by CHPP is not caused by the hyperthermia but by the peritoneal perfusion with saline solution containing anticancer drugs.

[Perioperative management for total en bloc spondylectomy--the effects of preoperative embolization and hypotensive anesthesia]

We retrospectively evaluated the effects of preoperative embolization and hypotensive anesthesia on total en bloc spondylectomy (TES) for solitary spinal metastases. In ten patients (treatment group), feeding arteries of spinal metastases were embolized preoperatively and controlled hypotensive anesthesia was induced during operation. In other ten patients (control group), these treatments were not applied. Intraoperative blood loss as well as the amount of blood transfused in the treatment group were significantly lower than those in the control group. Moreover, postoperative platelet counts in the treatment group were significantly higher than those in the control group. These findings indicate that embolization of feeding arteries of metastases and hypotensive anesthesia decrease intraoperative blood loss and may prevent postoperative complications in TES.

Left-molar approach improves the laryngeal view in patients with difficult laryngoscopy

BACKGROUND

The molar approach of laryngoscopy is reported to improve glottic view in sporadic cases of difficult laryngoscopy. The authors studied the effect of molar approaches and optimal external laryngeal manipulation (OELM) using the Macintosh blade.

METHODS

A series of 1,015 adult patients who underwent general anesthesia and tracheal intubation was studied. Laryngoscopy was carried out using a Macintosh no. 3 or 4 standard blade. Three consecutive trials of direct laryngoscopy using the midline and left- and right-molar approaches were carried out under full muscle relaxation with optimal head and neck positioning. The best glottic views were recorded for each approach with and without OELM.

RESULTS

Difficult laryngoscopy with a midline approach accounted for 6.5% (66 cases) before OELM and 1.97% (20 cases) after OELM. A left-molar approach with OELM further reduced difficult laryngoscopy to seven cases (P < 0.001 vs. midline approach with OELM); a right-molar approach with OELM reduced difficult laryngoscopy to 18 cases (P = 0.48).

CONCLUSIONS

The left-molar approach with OELM improves the laryngeal view in patients with difficult laryngoscopy.

The influence of hypoxia and hyperoxia on the kinetics of propofol emulsion

PURPOSE

To study the effect of hypoxia and hyperoxia on the pharmacokinetics of propofol emulsion, hepatic blood flow and arterial ketone body ratio in the rabbit.

METHODS

Twenty four male rabbits were anesthetized with isoflurane (1.5-2%) in oxygen. After the surgical procedure, isoflurane administration was discontinued and intravenous propofol infusion (30 mg x kg(-1) x hr(-1)) was started. The infusion rate of propofol was maintained throughout the study. After an initial 90 min period of propofol infusion, rabbits were randomly allocated to one of three groups: hypoxia (F(I)O2 = 0.1), normoxia (F(I)O2 = 0.21), and hyperoxia (F(I)O2 = 1.0). Propofol infusion was continued under the allocated F(I)O2 for 60 min. Propofol concentrations in arterial blood, total body clearance of propofol, hepatic blood flow and arterial ketone body ratio were measured.

RESULTS

The mean arterial propofol concentration at the end of infusion was higher in the hypoxia group (15.2 +/- 2.8 microg x mL(-1), mean +/- SD) than in the normoxia (7.4 +/- 1.7) and hyperoxia (8.0 +/- 1.9) groups (P < 0.05). Total body clearance of propofol, hepatic blood flow and arterial ketone body ratio were all reduced in the hypoxia group (P < 0.05). Total ketone body concentration in arterial blood increased in the hyperoxia group (P < 0.01).

CONCLUSION

Hypoxia produced an accumulation of propofol in blood and reduced propofol clearance. These changes could result from decreased hepatic blood flow and low cellular energy charge in the liver. Hyperoxia, on the other hand, increased total ketone body in arterial blood.

Dextran restores albumin-inhibited surface activity of pulmonary surfactant extract

We examined the effect of dextran (molecular weight 71,000) in counteracting the surfactant inhibitory action of plasma albumin. The surface adsorption time of 0.5 mg/ml modified natural surfactant (MNS; porcine lung extract consisting of phospholipids and hydrophobic surfactant proteins) with 7.5 mg/ml albumin decreased from 681 to 143 s by addition of dextran at a concentration of 10 mg/ml (P < 0.01). The minimum surface tension of 2.0 mg/ml MNS with 30 mg/ml albumin decreased from over 21 mN/m to below 3 mN/m when dextran was added at a concentration of 10 mg/ml (P < 0.01). Surfactant-deficient newborn rabbits given 10 ml/kg of a liquid containing 2.0 mg/ml MNS with 30 mg/ml albumin had a mean tidal volume </=5 ml/kg after 5 min of mechanical ventilation, but, in those animals given the liquid containing 10 mg/ml dextran also, the volume was >13 ml/kg (P < 0.05). Although the underlying mechanism remains to be elucidated, we conclude that dextran restores the albumin-inhibited surface activity of MNS.

[Use of personal computers by diplomats of anesthesiology in Japan]

Use of personal computers by diplomats of the Japanese Board of Anesthesiology working in Japanese university hospitals was investigated. Unsigned questionnaires were returned from 232 diplomats of 18 anesthesia departments. The age of responders ranged from twenties to sixties. Personal computer systems are used by 223 diplomats (96.1%), while nine (3.9%) do not use them. The computer systems used are: Apple Macintosh 77%, IBM compatible PC 21% and UNIX 2%. Although 197 diplomats have e-mail addresses, only 162 of them actually send and receive e-mails. Diplomats in fifties use e-mail most actively and those in sixties come second.

The effects of arm position on central spread of local anesthetics and on quality of the block with axillary brachial plexus block

BACKGROUND AND OBJECTIVES

Spread of local anesthetic solution in axillary brachial plexus block is thought to be influenced by the position of the arm and the use of compression maneuvers. We investigated how these two factors affected central local anesthetic spread and block quality.

METHODS

Radiographic spread of local anesthetic was studied in 80 adult patients. They received mepivacaine mixed with contrast agent through an indwelling catheter with the arm abducted to either 0 or 90 degrees , and with or without local digital compression. Central and peripheral spread of the contrast agent was evaluated with anteroposterior radiographs of the axilla. Block quality was studied in a separate series of 70 adult patients. They received mepivacaine with the arm abducted 0 degrees or 90 degrees . The degree of sensory and motor block was assessed 20 minutes after the injection.

RESULTS

Arm position at 0 degrees abduction promoted central spread of the contrast agent. Although digital compression suppressed peripheral spread effectively, it did not improve the central spread of the solution. Sensory block was comparable in all terminal nerves of the arm in both arm positions, whereas motor block of the radial nerve was promoted with no abduction.

CONCLUSIONS

The central spread of local anesthetics is facilitated by injection without abduction of the arm but not by the use of compression at the injection site. This, however, did not alter the quality of the block.

A comparison of the effects of propofol and sevoflurane on the systemic toxicity of intravenous bupivacaine in rats

We compared the effects of propofol and sevoflurane on bupivacaine-induced central nervous system and cardiovascular toxicity in rats. Thirty-four male Sprague-Dawley rats were anesthetized with 70% N2O/30% O2 plus the 50% effective dose (ED50) of propofol (propofol group, n = 12); 70% N2O/30% O2 plus ED50 of sevoflurane (sevoflurane group, n = 11); or 70% N2O/30% O2 (control group, n = 11). Bupivacaine was infused at a constant rate of 2 mg x kg(-1) x min(-1) while electrocardiogram, electroencephalogram, and invasive arterial pressure were continuously monitored. The cumulative doses of bupivacaine that induced dysrhythmias, seizures, and 50% reduction of heart rate were larger in the propofol and sevoflurane groups than in the control group. The cumulative dose of bupivacaine that induced a 50% reduction in the mean arterial blood pressure was larger in the propofol group than in the sevoflurane and control groups. The margin of safety, assessed by the time between the onset of dysrhythmias and 50% reduction of mean arterial blood pressure, was wider in the propofol group than in the sevoflurane group. We conclude that propofol and sevoflurane attenuate bupivacaine-induced dysrhythmias and seizures and that propofol has a wider margin of safety than sevoflurane.

IMPLICATIONS

In anesthetized patients, dysrhythmias may be the only warning sign of intravascular injection of bupivacaine. Because propofol has a wider margin of safety than sevoflurane, life-threatening cardiovascular depression may be prevented by stopping the injection of bupivacaine at the onset of dysrhythmias during propofol anesthesia.

[Comparison of transarterial technique and paresthesia technique of axillary brachial plexus block]

Axillary brachial plexus blocks were established in 40 patients using transarterial technique (n = 20) or paresthesia technique (n = 20). Sensory and motor blockades of nerves supplying the upper extremity were compared at 10, 20 and 30 minutes after the injection of local anesthetics (1.5% plain mepivacaine 40 ml). Sensory blockades of the radial nerve and axillary nerve were significantly higher with transarterial technique than paresthesia technique. The incidence of analgesia of the radial nerve at 30 min was 100% with transarterial technique and 70% with paresthesia technique. Sensory blockades of the other nerves and motor blockades of all nerves did not show any significant differences between the two techniques. Proximal and distal spreads of the local anesthetic-contrast medium mixture within the axillary neurovascular sheath were studied in 20 patients. No statistically significant difference was observed in the spread of contrast agent between the two techniques. Transarterial technique is a recommendable method for hand surgery and especially indicated for the surgery of the area supplied by the radial nerve.

Effects of surfactant proteins SP-B and SP-C on dynamic and static mechanics of immature lungs

To investigate the effects of surfactant proteins B (SP-B) and C (SP-C) on lung mechanics, we compared tidal and static lung volumes of immature rabbits anesthetized with pentobarbital sodium and given reconstituted test surfactants (RTS). With a series of RTS having various SP-B concentrations (0-0.7%) but a fixed SP-C concentration (1.4%), both the tidal volume with 25-cmH2O insufflation pressure and the static volume deflated to 5-cmH2O airway pressure increased, significantly correlating with the SP-B concentration: the former increased from 6.5 to 26.0 ml/kg (mean), and the latter increased from 6.4 to 31.8 ml/kg. With another series of RTS having a fixed SP-B concentration (0.7%) but various SP-C concentrations (0-1.4%), the tidal volume increased from 5.1 to 24.8 ml/kg, significantly correlating with the SP-C concentration, whereas the static volume increased from 3.4 to 32.0 ml/kg, the ceiling value, in the presence of a minimal concentration of SP-C (0. 18%). In conclusion, certain doses of SP-B and SP-C were indispensable for optimizing dynamic lung mechanics; the static mechanics, however, required significantly less SP-C.

Degradation of the 74 kDa form of L-histidine decarboxylase via the ubiquitin-proteasome pathway in a rat basophilic/mast cell line (RBL-2H3)

L-Histidine decarboxylase (HDC) is a dimer consisting of two identical 53 kDa subunits. On the other hand, the size of HDC deduced from its cDNA sequence is around 74 kDa, indicating that the translated 74 kDa form of HDC is subjected to post-translational processing to generate the 53 kDa form. However, modification of the translated 74 kDa form of HDC in histamine-forming cells is unknown. Here we demonstrate that the 74 kDa form is translated in rat basophilic leukemia cells, followed by conversion to the 53 kDa form, and that the 74 kDa form is a short half-life protein because of the degradation mediated by the ubiquitin-proteasome pathway. Degradation of the 74 kDa form was stimulated in the presence of an ATP-generating system, accompanied by ubiquitination, and inhibited by specific proteasome inhibitors such as ZL3H and lactacystin. A significant amount of proteasome activity was detected in RBL-2H3 cells.

Failed axillary brachial plexus block techniques result in high plasma concentrations of mepivacaine

BACKGROUND AND OBJECTIVES

Unintentional extrasheath injection causes failed axillary brachial plexus block. We wanted to find out if extrasheath injections produce higher plasma concentrations of local anesthetics compared to intrasheath injections. We also studied the incidence of extrasheath injection with radiographs.

METHODS

Axillary brachial plexus blocks were established using a catheter technique. Fifty milliliters of 1.5% mepivacaine without epinephrine mixed with contrast medium was injected through the catheter. An anteroposterior radiograph was used to determine the distribution of contrast medium. Mepivacaine concentrations in arterial plasma were compared when local anesthetic solution was injected unintentionally outside of the axillary neurovascular sheath (n = 6) and when it was injected correctly into the sheath (n = 6). The incidence of extrasheath injection was studied in a different series of 109 patients.

RESULTS

Arterial plasma mepivacaine concentrations were higher after extrasheath injection [8.0 (6.3-9.7) vs 5.8 (4.5-7.0), microg/mL, means (95% confidence intervals), P < .05]. Pharmacokinetic parameters such as mean residence time and total clearance did not differ between intra- and extrasheath injections. Extrasheath injection was observed in 3.7% (4/109) of cases.

CONCLUSION

Failed extrasheath injection of 50 mL 1.5% plain mepivacaine produces higher arterial plasma concentration in axillary brachial plexus block.

[Lack of hyperglycemic rebound after insulinoma removal: two case reports]

Two cases of anesthetic management for insulinoma were reported. The first patient, a 54-year-old man, suffering from repeated episodes of fasting hypoglycemia was scheduled for removal of insulinoma developed in the pancreas under isoflurane-nitrous oxide anesthesia. Preanesthetic plasma glucose concentration was 57 mg.dl-1. Glucose was continuously administered intravenously to maintain plasma glucose around 150 mg.dl-1. The second patient, a 65-year-old man suffering from several episodes of fasting hypoglycemia was scheduled for removal of insulinoma in the pancreas under isoflurane-nitrous oxide anesthesia. Preanesthetic plasma glucose was 103 mg.dl-1. An artificial pancreas was used to maintain plasma glucose at 140 mg.dl-1. In these patients, hyperglycemic rebound was not observed after removal of the insulinoma, and their perioperative courses were uneventful. Although relatively low immunoreactive insulin levels might relate, fine management of fluid and metabolism during preoperative period was thought as one of the reasons that hyperglycemic rebound did not occur in these patients. For the safe management of the patients with insulinoma, we recommend to maintain plasma glucose at the levels of mild hyperglycemia to prevent hypoglycemic episodes until the end of the removal.

Predicting difficult intubation with indirect laryngoscopy

BACKGROUND

It is not always possible to predict when tracheal intubation will be difficult or impossible. The authors wanted to determine whether indirect laryngoscopy could identify patients in whom intubation was difficult.

METHODS

Indirect laryngoscopy was done in 2,504 patients. The Wilson risk sum score and the modified Mallampati score were also studied in a different series of 3,680 patients for comparison. These predictive methods were compared according to three parameters: positive predictive value, sensitivity, and specificity.

RESULTS

Of 6,184 patients studied, the trachea proved difficult to intubate in 82 (1.3%). Positive predictive value (31%) and specificity (98.4%) with indirect laryngoscopy were greater than the other two predictive methods (P < 0.01), whereas sensitivity with indirect laryngoscopy (69.2%) was greater than that of the Wilson risk sum score (55.4%) (P < 0.01).

CONCLUSIONS

Although in 15% of patients indirect laryngoscopy could not be performed because of excessive gag reflex, indirect laryngoscopy can serve as an effective method to predict difficult intubation.

Prostate-specific antigen activates single-chain urokinase-type plasminogen activator

Prostate-specific antigen (PSA) increases in the plasma of patients with prostate cancer, and has therefore been used as a reliable tumor marker. It has been demonstrated that prostate cancer cells over-express urokinase-type plasminogen activator (uPA), which plays an important role in tumor invasion and metastasis. We found that PSA converts the single-chain proform of urokinase-type plasminogen activator (scuPA) to an active 2-chain form. The active 2-chain uPA generated from scuPA by PSA was measured by hydrolyzation of S-2444, a synthetic substrate for uPA. PSA activated scuPA time- and dose-dependently. SDS-PAGE analysis revealed that, after incubation with PSA, the intensity of the 55-kDa band of scuPA decreased concomitantly with increases in the intensity of the 2 bands at 33 kDa and 22 kDa. Amino-acid-sequence analysis indicated that PSA cleaved Lys158-Ile159, which corresponds with the site cleaved by plasmin. PSA did not enhance or impair the activity of the 2-chain form of uPA. These findings imply that PSA could be an initiator of the protease cascade involved in prostate-cancer invasion and metastasis.

Displacement of lidocaine from the lung after bolus injection of bupivacaine

The purpose of this study was to determine whether lidocaine was displaced from the lung after bolus injection of bupivacaine. Fourteen anesthetized rabbits were randomly assigned to either a bupivacaine or a control group. Lidocaine was infused at a rate of 10 mg.kg-1 x hr-1. After one hour of infusion, a bolus of bupivacaine (1 mg.kg-1) in normal saline (0.2 ml.kg-1) was injected into the central venous circulation in the bupivacaine group. The control group was injected with normal saline. After bolus injection, arterial blood samples were collected serially from an internal carotid artery at 1.2-sec intervals for 24 sec. The baseline concentration of lidocaine was 3.0 +/- 0.1 micrograms.ml-1 in the bupivacaine group and 3.2 +/- 0.1 micrograms.ml-1 in the control group (NS). Arterial concentrations of lidocaine increased to a maximum of 4.7 +/- 0.2 micrograms.ml-1 in the bupivacaine group (P = 0.0001). No increases were seen in the control group. These findings indicate that lidocaine was displaced from the lung into the blood after bolus injection of bupivacaine. The amount of lidocaine displaced during the first passage of bupivacaine through the lung was calculated to be 92.3 +/- 9.7 micrograms. It is concluded that lidocaine is displaced from the lung after bolus injection of bupivacaine.

Human glyoxalase I. cDNA cloning, expression, and sequence similarity to glyoxalase I from Pseudomonas putida

Glyoxalase I (EC 4.4.1.5) catalyzes the transformation of methylglyoxal and glutathione to S-lactoylglutathione. We have isolated human cDNA clones encoding glyoxalase I from a phorbol myristate acetate-treated U937 cDNA library. This cDNA encodes a protein of 184 amino acids with a calculated M(r) of 20,719. The amino acid composition calculated from the deduced amino acid sequence agreed with that reported for glyoxalase I purified from human erythrocytes. The Escherichia coli cells carrying the expression vector of this cDNA acquired methylglyoxal resistance and the cell lysate showed the high activity of glyoxalase I. The amino acid sequence of human glyoxalase I exhibited 57% identity with Pseudomonas putida glyoxalase I at the C-terminal two-thirds, suggesting that the two enzymes may have originated from a common ancestor.

Fibre digestion and digesta retention time in guinea-pigs (Cavia porcellus), degus (Octodon degus) and leaf-eared mice (Phyllotis darwini)

1. Digestibilities of feed and turnover time (1/k), Transit time (TT) and mean retention time (MRT: 1/k + TT) of fluid and particle markers were measured in the guinea-pig (Cavia porcellus), degu (Octodon degus) and leaf-eared mouse (Phyllotis darwini) fed a diet containing 50% alfalfa. 2. The digestibility of fibre and the retention time of digesta were highest in the guinea-pig followed by the degu and lowest in the leaf-eared mouse. 3. The difference in the retention time of digesta, resulting from the variation in the digestibility of fibre, between the three animals can be considered to be related to their body mass.

Animal models in micromanipulation

Micromanipulation is a useful technique for various studies of reproductive biology. Using this technique, we investigated the role of cAMP in the regulation of oocyte maturation. Anti cAMP serum was microinjected into oocyte cytoplasma. Immature oocytes resumed meiosis after microinjection and this result shows oocyte cAMP to be important for the intrafollicular meiotic arrest of oocyte and its decrease to cause resumption of meiosis. We also determined maturation promotion factor (MPF) activity in the mouse egg. Microinjection of cytoplasma from mature egg induced geminal vesicle break down of immature oocyte in the presence of dbcAMP. In addition, we detected MPF activity in cytoplasma of metaphase II oocyte. Some of the initial events of sperm-induced egg activation are accompanied by hydrolysis of phosphatidyl inositol which generates inositol trisphosphate (IP3). Mouse eggs microinjected with increasing concentration of IP3 revealed concentration dependent increase in conversion of the zona glycoprotein ZP2 to ZP2f. Modification of zona pellucida elicited by microinjection of IP3 are similar to those that occur following fertilisation. We also microinjected some cytoplasma of morula or 2 cell mouse embryo into 1 cell embryo of ICR mouse. After microinjection and culture, most of the embryo that reached 4 cells stage and 2 cell block of ICR mouse embryo was released significantly. These results suggest that some cytoplasmic factor(s) is a requisite for the development of embryo after fertilisation.

Lectin cytochemistry of the dark granules in the type 1 cells of Syrian hamster circumvallate taste buds

Lectin-gold complexes in the dark granules (DGs) and the dense substance (DS) of vallate taste buds were localized. Both the DGs and the DS were labelled with wheat-germ agglutinin, Ulex europeus agglutinin-I and peanut agglutinin. Their common reaction to these lectins suggested that the DGs contain carbohydrate components similar to those of the DS. The results provide cytochemical evidence that the DS in the taste pit represents, at least in part, the content of the DGs in the type 1 cells.

Mode of action of a new nalidixic acid derivative, AB206

A new chemotherapeutic agent, AB206, shows potent antibacterial activity against gram-negative bacteria, including most of the nalidixic acid-resistant strains tested. It strongly inhibits deoxyribonucleic acid (DNA) synthesis in Escherichia coli, but only slightly inhibits ribonucleic acid and protein synthesis. Its activity on DNA synthesis in vivo and in vitro is greater than that of nalidixic acid. AB206 also strongly inhibits in vivo DNA synthesis in nalidixic acid-susceptible and -resistant clinical isolates of Proteus and Serratia. AB206 shows high penetrability into E. coli cells, as demonstrated by antibacterial activity with or without ethylenediaminetetraacetic acid, inhibition of in vivo and in vitro DNA synthesis, and uptake of the drug into cells, as compared to nalidixic acid. It appears that the high antibacterial activity of AB206 may be explained both by its potent inhibitory action against DNA synthesis and also by its high penetrability into bacterial cells.