Discovery of two novel HLA-B alleles, B*46:13:03 and B*15:189, in two Taiwanese volunteer bone marrow donors by sequence-based typing

We report here two novel HLA-B alleles, B*46:13:03 and B*15:189, discovered in two Taiwanese volunteer bone marrow donors. The sequence of B*15:189 has a nucleotide sequence possibly derived from a recombination event between HLA-B*39:01:01 and B*15:01:01:01, while the origin of the sequence B*46:13:03 was less obvious to postulate, considering the low frequency of B*46:13 in the general population and the silent mutations involved. Our report here adds further HLA polymorphism to the growing lists of HLA-B*46 and HLA-B*15 and provides an additional HLA information for donor search programme for patients undergoing transplant.

Oriental HLA-A*11:90 detected in a Taiwanese cord blood sample and the haplotype in association with A*11:90 allele

We report here an HLA-A allele, A*11:90, found in a Taiwanese cord blood sample using DNA sequence-based typing (SBT) protocol after observing an anomalous reaction pattern in a sequence-specific oligonucleotide (SSO) typing exercise. The sequence of A*11:90 is identical to A*11:01:01, the most predominant A*11 variant in Taiwanese, in exon 2 but differs from A*11:01:01 in exon 3 by two nucleotide substitutions at codon 163 (c.487C>G and c.488G>A), resulting R163E. In comparison with the sequence of A*11:02:01, the second most predominant subtype of A*11 in Taiwanese A*11:90 has one nucleotide difference at codon 19 (c.55A>G) in exon 2 resulting K19E and two nucleotides variations at codon 163 (c.487C>G and c.488G>A) in exon 3 resulting R163E. HLA-A*11:90-B*40:02-DRB1*11:01 is the deduced probable HLA haplotype in association with A*11:90. The generation of A*11:90 is thought to involve a DNA recombination event between alleles A*11:01:01 and A*80:01 where A*80:01 donated a fragment of the DNA sequence (from n.t. 487 to n.t. 497) to the recipient sequence of A*11:01:01.

Detection of two HLA-A alleles, A*31:30 and A*26:20, in two Taiwanese volunteer bone marrow donors by sequence-based typing

We here report detection of a novel sequence of HLA-A*31:30 and a confirmatory sequence of HLA*26:20 from two Taiwanese individuals. The sequence of A*31:30 is identical to that of A*31:01:02 in exons 2 and 3, except one nucleotide (n.t.) substitution c.539T > G resulting in p.Leu180Trp. The sequence of A*26:20 is identical to A*26:01:01 in exons 2 and 3, except a segment of the sequence from n.t. 78 to n.t.102. The mismatched sequence segment is identical to a sequence segment of A*02:03:01, suggesting that the formation of A*26:20 was resulted from a DNA recombination event between A*26:01:01 and A*02:03:01 sequences. A*26:20 differs from A*26:01:01 with c.98A > T resulting in p.Tyr33Phe.

Identification of a novel HLA-DQB1 allele, DQB1*0326, in a College of American Pathologists 2009 survey specimen

We identified a novel DQB1*0326 allele from a proficiency test sample provided by the College of American Pathologists (CAP) medical society. This novel DQB1 allele was unexpectedly discovered by sequence-based typing method in an attempt to resolve a discrepant typing result between the CAP survey report and our laboratory report. This novel DQB1 allele is most similar to DQB1*030302 and DQB1*0311. DQB1*0326 has a nucleotide substitution resulting an amino acid change when compared with DQB1*030302 (M to L) and it differs from DQB1*0311 by one nucleotide variation causing an amino acid replacement (A to D).

Detection of a rare Caucasoid HLA-DRB1*0337 in a Taiwanese bone marrow donor using sequence-based typing method

We here describe the identification of HLA-DRB1*0337, using sequence-based typing (SBT) method, in a Taiwanese bone marrow donor intrigued by a casual curiosity on the donor's racial background. On high-resolution sequence-specific primer (SSP) typing we observed misleading reaction patterns due to similarity of DNA sequences in the exon 2 of DRB1*0301, *0317, *0337 and *1139. When encountering rare alleles in HLA typing, it is important to pay extra attentions to avoid pitfalls and shortcomings of SSP typing kits routinely used and bear in mind that constant up-dating of high-resolution SSP typing kits to be able to distinguish newly reported alleles. SBT may be considered as a back-up HLA typing method to confirm rare alleles.

A novel HLA-B allele, B*5214, detected in a Taiwanese volunteer bone marrow donor using a sequence-based typing method

HLA-B*5214, a novel rare allele of HLA-B*52 variant, was found in a Taiwanese volunteer bone marrow donor by sequence-based typing method. The sequence of B*5214 is identical to that of B*520101 in exon 2 but differs from B*520101 in exon 3 at nucleotide positions 419 A-->T and 435 A-->G. Alteration of these two nucleotides resulted an amino acid substitution at amino acid residue 116 Y-->F ( TAC-->TTC) and a silent exchange at residue 121 K-->K (AAA-->AAG).

Identification of a novel HLA-A allele, A*1131, in a Taiwanese

Here we report the identification and sequence analysis of a new HLA-A11* variant, A*1131 allele, found in a Taiwanese volunteer bone marrow donor. The novel A*11 variant is identical to A*1125 in exon 2 but differs from A*1125 in exon 3 by one nucleotide substitution at position 527 causing an amino acid change at codon 152 E-->V (GAG-->GTG). In comparison with HLA-A*110101, allele A*1131 has three nucleotide differences in exon 3: 527 C-->T, 538 C-->T and 539 A-->T leading to two amino acid variations at residues 152 A-->V and 156 Q-->L.

Unrelated haematopoietic stem cell transplantation in Taiwan and beyond

Since its inception in October 1993, the world-renowned Buddhist Tzu Chi Marrow Donor Registry has facilitated more than 1800 cases of stem cell donations for patients in 27 countries to date. Under the auspices of the Buddhist Tzu Chi Stem Cells Center (BTCSCC), the Registry (> 310,000 donors) offers, on average, one case of stem cell donation every day to national or international transplantation community. The accomplishment of the Registry stems from the philosophy and spirit of giving without reward that was inspired by its founder Dharma Master Cheng Yen, the Samaritan devotions of selfless voluntary stem cell donors and the efforts from a dedicated network of volunteer workers. Demographically speaking, slightly less than one third of the donations are provided to domestic patients and the rest to mainland China and countries in Asia, North America, Europe, Middle East, Oceania, and South Africa. While most of the patients belong to the Oriental ethnic group, a few of the patients are non-Oriental. In addition to the Registry, a non-profit umbilical cord blood (UCB) bank is operating since 2002 to provide a complimentary role for patients unable to identify appropriate bone marrow stem cell donors in the Registry in time. To date, with an inventory of over 12,000 units of UCB cryopreserved in the Tzu Chi Cord Blood Bank, 47 units have been employed in 37 cases of transplantation for both paediatric and adult patients domestically and internationally. The fact that Buddhist Tzu Chi Marrow Donor Registry and Cord Blood Bank are established and operating without governmental financial support is unique and special. To facilitate haematopoietic stem cells to its domestic patients experiencing financial burdens, the BTCSCC offers financial aids to the underprivileged for their medical relief. This humanitarian approach and compassion is definitely a role model for many countries in the world.

Detection of a novel HLA-B27 allele, B*2740, in Taiwanese volunteer bone marrow donors by sequence-based typing: curiosity rewarded

We report here a novel HLA-B allele, B*2740, discovered in Taiwanese volunteer marrow donors. The new sequence has nucleotide variation at position 527 (T-->A) as compared to B*2708. The nucleotide change caused an amino acid substitution from valine (V) to glutamic acid (E) at codon 152. Since B*2740 carries sequence confers to HLA-Bw6 public epitope we believe that this novel B*27 allele might have been generated from a gene conversion involving a Bw4-specific allele (probably B*2704) and a Bw6-specific allele.

Prostacyclin analogue (OP-2507) induces delayed ex vivo neutrophil apoptosis and attenuates reperfusion-induced hepatic microcirculatory derangement in rats

Leukocyte-endothelial adherence and changes of blood flow in microcirculation are associated with the development of ischemia-reperfusion injury in the liver. Polymorphonuclear neutrophil (PMN) apoptosis is essential to maintain homeostasis and plays a major role in limiting the reperfusion-related systemic effects. This study investigates the effects of a prostacyclin analogue (OP-2507) on hepatic ischemia-reperfusion injury. Adult, male Sprague-Dawley rats were used. Five groups were evaluated: (1) sham-operated control, n = 8; (2) ischemia control (1-h ischemia, 5-h reperfusion), n = 8; (3) intravenous infusion with OP-2507 ([15 cis-14-propylcyclohexyl]-16,17,18,19,20-pentanor-9-deoxy-9alpha,6-ni-trilo-PGF, methyl eater) at a dose of 1 microg/kg/min plus ischemia, n = 8; (4) intravenous infusion with OP-2507 at a dose of 0.1 microg/kg/min plus ischemia, n = 8, and (5) sham-operated control and intravenous infusion with OP-2507 at a dose of 1 microg/kg/min, N =8. Laser-Doppler flowmetry and an in vivo microscopy were used to investigate hepatic microcirculation. PMN apoptosis was quantitated by flow-cytometric labeling of DNA strand breaks. Tissue malondialdehyde and adenosine triphosphate were determined at the end of the experiment. Compared with the ischemia control group, OP-2507 significantly improved harmful insults following ischemia-reperfusion. The changes of mean systemic arterial pressure following ischemia-reperfusion have been significantly attenuated by OP- 2507 at both doses. OP-2507 lessened adherent leukocyte count in the post-sinusoid venules, and improved flow velocity in these areas. OP-2507 at both doses reduced malondialdehyde and increased adenosine triphosphate levels and this effect was dose-related. The activity of delayed ex vivo PMN apoptosis was significantly lower in the ischemia group than that of control and treatment groups. OP-2507 induced the activity of PMN apoptosis and its effect is dose-related, also. The PMN apoptosis activity is strongly correlated with parenchymal damages. This study demonstrates that OP-2507 treatment with ischemia may ameliorate the ischemia-reperfusion injury of the liver in the rat model, and increase spontaneous neutrophil apoptosis ex vivo.

The intubating laryngeal mask airway in severe ankylosing spondylitis

PURPOSE

To evaluate the use of inhalational induction followed by intubation through the intubating laryngeal mask (ILM) for patients with severe ankylosing spondylitis undergoing elective surgery who prefer airway management under anesthesia.

METHODS

Nine patients undergoing a total of 11 procedures were enrolled in the study. Fentanyl 2 microg*kg(-1), midazolam 0.035 mg*kg(-1) and sevoflurane in oxygen 100% were used for induction. The ILM was inserted when the end-tidal sevoflurane concentration reached 3%. After an effective airway was established, atracurium 0.5 mg*kg(-1) was given. A polyvinyl chloride tube in the reversed position using a blind technique was used to intubate the trachea.

RESULTS

The ILM provided an effective airway on 11/11 occasions at the first attempt. Intubation was successful at the first attempt on 7/11 occasions, at the second attempt on 2/11 and at the third attempt in 1/11. Intubation failed in one patient. The mean (range) minimal oxygen saturation was 99.4% (97-100%). There were no problems with ILM removal.

CONCLUSION

Inhalational induction followed by ILM insertion and blind intubation is a reasonable option in patients with severe ankylosing spondylitis undergoing elective surgery who prefer airway management under anesthesia.

Simultaneous determination of unbound ropivacaine in rat blood and brain using microdialysis

To investigate the pharmacokinetics of ropivacaine in rat blood and brain, a sensitive HPLC method and microdialysis were developed for the simultaneous determination of unbound ropivacaine in rat blood and brain. Adult, male Sprague-Dawley rats (290-350 g) were anesthetized with sodium pentobarbital (50 mg/kg, i.p.). Two microdialysis probes were inserted, one into the jugular vein toward right atrium, and one into the brain striatum of rats. Ropivacaine (5 mg/kg, i.v.) was then administered via the femoral vein. Blood and brain dialysates were collected and eluted with a mobile phase containing methanol-acetonitrite-20 mM monosodium phosphoric acid (pH 5.5) (10:40:50, v/v/v) in a liquid chromatographic system. Separation of ropivacaine was achieved by a CN column (Phenomenex Luna, 250x4.6 mm, particle size 5 microm; Torrance, CA, USA) within 10 min. The UV detector wavelength was set at 205 nm and the detection limit of ropivacaine was 20 ng/ml. The intra- and inter-day accuracy and precision of the analyses were less than 10% in the ranges of 0.02-5 microg/ml. The pharmacokinetic data were calculated from the individual animal measurements of dialysate concentration versus time. This method exhibits no endogenous interference and its sensitivity is sufficient for the determination of biological samples. The present results confirm that microdialysis sampling followed by LC separation with UV detection represents a viable approach for the measurement of free ropivacaine in rat brain and plasma.

Hemodynamic responses of thiopental and propofol in different-aged patients during endotracheal intubation

BACKGROUND

Thiopental and propofol are 2 popularly used anesthetic induction agents that have different pharmacological and pharmacokinetic actions. It is not clear how the hemodynamic responses differ in different-aged patients using these 2 drugs for anesthetic induction. The aim of this study was to investigate the hemodynamic responses to propofol and thiopental of different-aged patients during endotracheal intubation.

METHODS

Sixty patients, 20 to 83 years old, were included in this study. Patients were randomly divided into 6 groups according to age and different inductive anesthetics. Non-invasive blood pressure (NIBP) monitoring was performed every minute before anesthesia, during anesthetic induction with 5 mg.kg-1 thiopental or 2 mg.kg-1 propofol intravenously, and after intubation.

RESULTS

Propofol induction produced a smaller mean arterial pressure increase immediately after intubation than did thiopental induction in adult and elderly groups (101.0 +/- 18.5 and 104.0 +/- 21.1 mmHg in the propofol groups vs. 138.3 +/- 17.1 and 138.9 +/- 16.1 mmHg in the thiopental groups at 1 minute after intubation, p < 0.001 and p = 0.001, respectively). Differences in heart rate between propofol and thiopental groups were found in young and adult groups (85.1 +/- 9.2 and 81.7 +/- 10.9 in the propofol groups vs. 94.5 +/- 9.9 and 95.0 +/- 14.0 beats per minute in the thiopental groups at 1 minute after intubation, p = 0.041 and p = 0.029, respectively).

CONCLUSION

Propofol induction produced more stable hemodynamics after intubation in adult and elderly patients than did thiopental induction. Therefore, it is safer to use propofol for induction and intubation in adult and elderly patients.

Mechanisms of thrombin-induced MAPK activation associated with cell proliferation in human cultured tracheal smooth muscle cells

The elevated level of thrombin has been detected in the airway fluids of asthmatic patients. However, the implication of thrombin in the pathogenesis of bronchial hyperreactivity was not completely understood. Therefore, in this study we investigated the effect of thrombin on cell proliferation and p42/p44 mitogen-activated protein kinase (MAPK) activation in human tracheal smooth muscle cells (TSMCs). Thrombin stimulated [3H]thymidine incorporation and p42/p44 MAPK phosphorylation in a time- and concentration-dependent manner in TSMCs. Pretreatment of TSMCs with pertussis toxin (PTX) significantly inhibited [3H]thymidine incorporation and phosphorylation of MAPK induced by thrombin. These responses were attenuated by tyrosine kinase inhibitors genistein and herbimycin A, phosphatidyl inositide (PI)-phospholipase C (PLC) inhibitor U73122, protein kinase C (PKC) inhibitor GF109203X, removal of Ca(2+) by addition of BAPTA/AM plus EGTA, and PI 3-kinase inhibitors wortmannin and LY294002. In addition, thrombin-induced [3H]-thymidine incorporation and p42/p44 MAPK phosphorylation was completely inhibited by PD98059 (an inhibitor of MEK1/2), indicating that activation of MEK1/2 was required for these responses. Furthermore, overexpression of dominant negative mutants, RasN17 and Raf-301, significantly suppressed p42/p44 MAPK activation induced by thrombin and PDGF-BB, indicating that Ras and Raf may be required for activation of these kinases. These results conclude that the mitogenic effect of thrombin was mediated through the activation of Ras/Raf/MEK/MAPK pathway. Thrombin-mediated MAPK activation was modulated by PI-PLC, Ca(2+), PKC, tyrosine kinase, and PI 3-kinase associated with cell proliferation in cultured human TSMCs.

The intubating LMA: a comparison of insertion techniques with conventional tracheal tubes

PURPOSE

To compare the performance of the intubating laryngeal mask airway (ILMA) in assisting blind tracheal intubation with conventional tracheal tubes of different curvatures and the frequency of possible associated complications.

METHODS

After informed consent, 240 ASA I-II adults undergoing elective surgery participated in a randomized, single blind clinical trial to receive blind trachea intubation via ILMA with a conventional tracheal tube curved with normal (Normal group) or reversed (Reverse group) direction. More than three attempts at intubation was regarded as failure. The lowest oxygen saturation during intubation was recorded and postintubation sore throat and hoarseness were evaluated with verbal analog scales.

RESULTS

The overall success rates of intubation with Normal and Reverse groups were not different (96.7% and 94.2% respectively). Successful intubation at the first attempt was higher in the Reverse group than in the Normal group (86.7% vs 75.0%, P=0.033). The incidence of sore throat was higher in the Normal group than in the Reverse group (19.2% vs 9.2% respectively, P =0.042).

CONCLUSIONS

Blind trachea intubation via an ILMA with the conventional curved tracheal tube is feasible and highly successful. Reverse curve direction is preferable at the first attempt of intubation for its higher success rate and lower incidence of complications.

Effects of timing of diatrizoate (water-soluble contrast medium) administration on pancreatic microcirculatory derangement in cerulein pancreatitis in rats

OBJECTIVE

We investigated whether the timing of administration of contrast medium after onset of acute pancreatitis is critical in determining the magnitude of microcirculatory derangement.

METHODS

An acute pancreatitis model in male Sprague-Dawley rats (225-275 g) was established by continuous infusion of cerulein (15 mg/kg per hour). The mean arterial pressure was monitored continuously by means of a femoral artery catheter. Diatrizoate (Hypaque-76), a water-soluble contrast medium, was delivered through a femoral vein catheter at doses corresponding to those given to humans, either 1, 2, or 3 hours after pancreatitis induction. In vivo microscopy and laser-Doppler flowmetry were used to investigate microcirculatory derangement. The water contents of the pancreas and lung, the malondialdehyde levels of the pancreas, and the trypsinogen activation peptide levels in the serum were measured at the end of the experiment (8 hours after infusion of cerulein).

RESULTS

Early administration of contrast medium (1 hour after pancreatitis induction) resulted in significantly greater changes in microcirculation and mean arterial pressure than did late administration (2 or 3 hours after pancreatitis induction). Rats given contrast medium 1 hour after induction also had highest pancreas and lung water contents, the highest pancreas malondialdehyde levels, and the highest serum trypsinogen activation peptide levels.

CONCLUSION

These results show that a water soluble contrast medium that is often used for computed tomographic imaging of the pancreas can adversely affect the pancreatic microcirculatory parameters, such as tissue perfusion and leukocyte sticking, and hemodynamics in a cerulein-induced model of acute pancreatitis. Early administration seems to cause more severe derangement of the pancreatic microcirculation.

Selective inhibition of inducible nitric oxide in ischemia-reperfusion of rat small intestine

PURPOSE

We investigated the role of constitutive and inducible nitric oxide (NO) synthases in intestinal ischemia-reperfusion (I/R) injury by observing the alterations in hemodynamics and intestinal microcirculation in response to I/R in rats, with or without inhibitors of NO synthases.

METHODS

Adult male Sprague-Dawley rats (n = 9/group) received a standard I/R procedure alone: I/R plus intravenous administration of aminoguanidine (an inhibitor of inducible NO synthase); I/R plus L-NAME (NG-nitro-L-arginine methyl ester, an inhibitor of constitutive and inducible NO synthase); IR + L-Arg (L-arginine, an NO precursor); or a sham operation plus the vehicle. The I/R procedure was performed by clamping the perfusion vessels of a segment of the terminal ileum, and medication was administered intravenously before and after intestinal ischemia. The intestinal perfusion and leukocyte-endothelial interactions were evaluated with in vivo microscopy and laser Doppler flowmetry. Surface expression of CD11b (an adhesion molecule) of circulating granulocytes was measured with flow cytometry.

RESULTS

Intestinal I/R produced circulatory alterations, intestinal microcirculatory derangement, energy depletion, and lipid peroxidation. Aminoguanidine significantly attenuated the reperfusion-related depression of mean arterial pressure (MAP), the decrease in intestinal perfusion index, the decrease in tissue ATP preservation, the increase in tissue malondialdehyde (MDA) level, and the expression of CD11b of circulating granulocytes. Administration of L-NAME had only minor and transient effects on reperfusion-related changes of MAP, intestinal flux, numbers of adherent leukocytes, and CD11b expression, but had some protective effects on tissue MDA and adenosine triphosphate levels and flow velocity. L-Arg further decreased the MAP but did not affect reperfusion-related variables.

CONCLUSIONS

Our results show that the selective inhibition of inducible NO synthase by aminoguanidine attenuates the hemodynamic and microcirculatory derangement that results from intestinal I/R.

Aminoguanidine attenuates hemodynamic and microcirculatory derangement in rat intestinal ischemia and reperfusion

BACKGROUND

Nitric oxide (NO) participates in the regulation of hemodynamic and microcirculatory changes in intestinal ischemia and reperfusion (I/R). However, the nature of the involvement of an inducible NO release has been controversial. This study evaluates the impact of an inducible NO synthase inhibitor, aminoguanidine, used as a treatment in a rat intestinal I/R model.

METHODS

We investigated the hemodynamics by measuring the mean arterial pressure (MAP), and the microcirculatory responses of the intestine and liver to systemically administered aminoguanidine by use of laser-Doppler flowmetry (LDF), in vivo microscopy, and flow cytometry.

RESULTS

During the 30-min ischemia of the selected 20-cm ileal segment, no MAP change was noted. At reperfusion, a marked decrease of MAP was noted and the lowest levels were noted 3 hours after reperfusion (67 +/- 4% vs. 99 +/- 5% in sham-operated control animals). A marked decrease in liver perfusion as measured by LDF was noted 1 hour after reperfusion and remained low at 5 hours (72 +/- 4% vs. 97 +/- 3% in sham-operated control animals). A marked decrease in intestine perfusion was noted by using LDF 1 hour after reperfusion and remained low at 5 hours (43 +/- 3% vs. 92 +/- 4% in sham-operated control animals). The flow velocity of the postcapillary venules of the intestine was markedly decreased (1.01 +/- 0.62 vs. 2.67 +/- 0.34 mm/s in sham-operated control animals) at 5 hours after reperfusion. The flow velocity of the postsinusoidal venules of the liver was also markedly decreased (1.01 +/- 0.62% vs. 2.67 +/- 0.34% in sham-operated control animals). Leukocyte-endothelial interaction (adhesion) was increased in the postcapillary venules of the intestine (54 +/- 12 vs. 6 +/- 4/microm2 in sham-operated control animals) and in the postsinusoidal venules of the liver (32 +/- 8 vs. 2 +/- 2/microm2 in sham-operated control animals). Concomitantly, the granulocyte count was increased (9.1 +/- 0.6 vs. 2.1 +/- 0.3% of total circulating leukocytes in sham-operated control animals), with an increase of CD 11b expression. Aminoguanidine administration (1 mg/kg) 0.5 hour before ischemia and 1 hour after reperfusion significantly increased MAP, increased intestine and liver perfusion, decreased adhesion, and decreased circulating granulocytes and CD 11b expression.

CONCLUSION

Inhibition of an inducible NO release by aminoguanidine in intestinal I/R can attenuate hemodynamic and microcirculatory derangement.

Neutrophil elastase inhibitor (ONO-5046) attenuates reperfusion-induced hepatic microcirculatory derangement, energy depletion and lipid peroxidation in rats

Microcirculatory derangement, energy depletion, and lipid peroxidation are associated with the development of ischemia-reperfusion injury in the liver. This study investigated the effects of a neutrophil elastase inhibitor (ONO-5046) on hepatic ischemia-reperfusion injury. Adult, male Sprague-Dawley rats were divided into four treatment groups: 1) sham-operated control (laparotomy only, no ischemia) and saline injection (1 mL/kg), n = 6; 2) ischemia control (1-h ischemia, 2-h reperfusion) and saline injection (1 mL/kg), n = 6; 3) intravenous injection with ONO-5046 at a dose of 1 mg/kg 5 min before ischemia and immediately after reperfusion plus 1-h ischemia and 2-h reperfusion, n = 6; and 4) intravenous injection with ONO-5046 at a dose of 10 mg/kg 5 min before ischemia and immediately after reperfusion plus 1-h ischemia and 2-h reperfusion, n = 6. A laser-Doppler flowmeter and in vivo microscopy were used to investigate hepatic microcirculation. Tissue malondialdehyde (MDA) and adenosine triphosphate (ATP) levels were determined at the end of the experiment.

RESULTS

Compared with ischemia alone, ONO-5046 significantly reduced the extent of microcirculatory and hemodynamic derangement after ischemia-reperfusion. ONO-5046 at both doses significantly attenuated decreases in mean arterial pressure. ONO-5046 lessened adherent leukocyte count and improved flow velocity in the sinusoids and postsinusoidal venules. ONO-5046 at the dose of 10m/kg reduced MDA (1.97 +/- 0.54 micromol/g protein vs. 3.58 +/- 1.21 micromol/g protein in the ischemia and reperfusion group) and increased ATP levels (2.62 +/- 0.19 micromol/g wet wt vs. 0.57 +/- 0.37 pmol/g wet wt in the ischemia and reperfusion group), whereas ONO-5046 at a smaller dose (1 mg/kg) had lesser but significant effects on MDA and ATP alterations. This study demonstrates that treatment with ONO-5046, a neutrophil elastase inhibitor, can ameliorate ischemia-reperfusion injury of the rat liver.

Mechanisms underlying the inhibitory effect of propofol on the contraction of canine airway smooth muscle

BACKGROUND

Propofol has been shown to produce relaxation of preconstricted airway smooth muscle. Although the inhibition of calcium mobilization is supposed to be the major mechanism of action, the whole picture of the mechanisms is not completely clear.

METHODS

Contractile response was performed using canine tracheal rings. The effects of propofol on carbachol-induced mobilization of intracellular Ca2+ and phosphoinositide hydrolysis were measured using cultured canine tracheal smooth muscle cells by monitoring fura-2 signal and assessing the accumulation of [3H]-inositol phosphates. To detect the effect of propofol on muscarinic receptor density and affinity, [3H]N-methyl-scopolamine was used as a radioligand for receptor binding assay.

RESULTS

Pretreatment with propofol shifts the concentration-response curves of carbachol-induced smooth muscle contraction to the right in a concentration-dependent manner without changing the maximal response. Propofol not only decreased the release of Ca2+ from internal stores but also inhibited the calcium influx induced by carbachol. In addition, carbachol-induced inositol phosphate accumulation was attenuated by propofol; the inhibitory pattern was similar to the contractile response. Moreover, propofol did not alter the density of muscarinic receptors. The dissociation constant value was not altered by pretreatment with 100 microM propofol but was significantly increased by 300 microM (propofol, 952+/-229 pM; control, 588+/-98 pM; P<0.05).

CONCLUSIONS

Propofol attenuates the muscarinic receptor-mediated airway muscle contraction. The mechanism underlying these effects was attenuation of inositol phosphate generation and inhibition of Ca2+ mobilization through the inhibition of the receptor-coupled signal-transduction pathway.

Spinal nitric oxide participates in the control of the blood pressure during graded hemorrhage in the conscious rat

We sought to evaluate the role of spinal nitric oxide (NO) in the control of blood pressure in the conscious animal and determine its possible participation in the progression of hemorrhagic shock. Adult, male Sprague-Dawley rats were chronically prepared with intrathecal, intravenous, and intra-arterial catheters. We first investigated the role of spinal NO on blood pressure control by intrathecal administration of N(G)-nitro-L-arginine methyl ester hydrochloride (L-NAME) at 0.37 micromol, 0.74 micromol. or 1.48 micromol. A dose-related increase in blood pressure was observed. We next pretreated animals with intrathecal or intravenous L-NAME at 0.37 micromol and induced the animal to shock by graded hemorrhage. Animals that received vehicle control or intravenous L-NAME had a decrease in blood pressure after 12% of the total circulatory blood volume (TBV) had been removed and developed severe hypotension after 24% TBV was bled. On the other hand, intrathecal pretreatment of L-NAME significantly attenuated the decrease in blood pressure. The blood pressure was maintained until 40% TBV had been withdrawn. We concluded that inhibition of NO synthase, in the spinal cord, increased blood pressure in a dose-dependent manner, and hemorrhagic shock induced by graded hemorrhage may involve an upregulation mechanism of spinal NO synthase in producing severe hypotension in conscious rats.

Fatal hyperkalemia during rapid and massive blood transfusion in a child undergoing hip surgery--a case report

We report a girl who developed severe and fatal hyperkalemia following rapid and massive blood transfusion during surgery. She was 7-year-old, 20-kg in weight, and received wide resection of the femoral bone with custom prosthesis implant because of malignant femoral osteosarcoma. During the procedure, bleeding was active and profuse and amounted to about 3,000 mL in 4 h, eventuating in shock. Despite rapid transfusion with 15 units of packed red blood cells (RBC) still she remained hypotensive and hypovolemic. When we switched to give her whole blood, actually 100 mL having been given, widening of QRS complex followed immediately by cardiac arrest developed. Cardiopulmonary resuscitation although started at once was unsuccessful. At this juncture, arterial blood gas analysis showed acidosis and severe hyperkalemia (10.3 mmol/L), possibly resulting from transfusion of blood of older storage. The case reminded us once again the importance and necessity of the use of potassium-low blood component (fresh, saline-washed RBCs) in case of massive and rapid blood transfusion especially in pediatric patients with hypovolemia and low cardiac output.

Dynamic measurement of metabolic function in the rat liver: an application of reverse microdialysis

BACKGROUND

Traditional markers of liver function and microsomal activity tests require regular samplings and tissue removal. The microdialysis technique is a promising tool for pharmacokinetic study without the need for actually removing samples of those tissues and fluids. We verified the possibility of using reverse microdialysis for dynamic monitoring of hepatic metabolic function.

METHODS

Adult male Sprague-Dawley rats were used and anesthetized using pentobarbital sodium. Reverse microdialysis was done by implanting a microdialysis probe into the middle lobe of the liver; the probe was then perfused with a lidocaine-containing solution. Concentrations of lidocaine and its major metabolite, monoethylglycinexylidide (MEGX), were measured in the dialysate. Metabolic ability was assessed by dividing the MEGX production by lidocaine administration. Hepatic ischemia-reperfusion and liver cirrhosis models were used to verify its application in dynamic measurement of liver metabolic function.

RESULTS

The implantable microdialysis probe had stable contact with the liver tissue. In normal rats, 4.73 +/- 0.41% of the lidocaine was transformed to MEGX in 20 min. Only 16% of this value was preserved in cirrhotic animals. Hepatic ischemia for 20 min transiently depressed the MEGX formation and did not cause further injury after reperfusion.

CONCLUSION

We confirmed the ability of an implantable microdialysis probe to be in constant contact with the liver tissue and thus deliver a stable transmission of chemicals across a microdialysis membrane for a certain period of time. We also verified the feasibility of reverse microdialysis as a tool for the dynamic measurement of hepatic metabolic function.

Power spectral analysis of arterial and central venous pressure signals during graded hemorrhage in anesthetized rats

Based on simultaneous power spectral analysis of systemic arterial pressure (SAP) and central venous pressure (CVP) signals in rats anesthetized with pentobarbital sodium, we assessed the hypotheses that subtle changes in the SAP spectrum exist during hemorrhagic shock, and that the CVP spectrum is a feasible index for central blood volume during acute graded blood loss. During Stage I hemorrhagic shock seen after reduction in 10% of total blood volume (TBV), there was a significant increase in the power of both the very low frequency (VLF, 0-.25 Hz) and low frequency (LF, .25-.8 Hz) components, along with a moderate decrease in the very high frequency (VHF, 5-9 Hz) component, of SAP signals. Substantial reduction in VLF, LF, and VHF components in the SAP spectrum occurred after a blood loss of 25% of TBV (Stage II), which persisted during Stage III hemorrhagic shock when the withdrawn blood reached 50% of TBV and the mean SAP maintained at 40 mm Hg. The depressed SAP-VLF and SAP-LF components sustained the period of spontaneous recovery and subsequent retransfusion of shed blood, although the power of SAP-VHF component gradually elevated during these two periods. The power of the high-frequency (HF, .8-2.4 Hz) component of SAP signals increased discernibly only during Stage III, became significant on spontaneous recovery, and declined during retransfusion. Although CVP and CVP-VHF component progressively declined, the power of the CVP-HF component manifested a gradual increase that was significantly and reversely correlated with the reduction in TBV. We conclude that differential changes in individual components of the SAP spectrum occur during hemorrhagic shock, and that the CVP-HF component may be a reliable indicator for central blood volume during acute graded blood loss.

Softened endothracheal tube reduces the incidence and severity of epistaxis following nasotracheal intubation

BACKGROUND

Many complications were reported to be related with nasotracheal intubation. Various chemical or mechanical techniques have been proposed to decrease hemorrhage and trauma associated with nasotracheal intubation but the results remain controversial. We conducted a prospective, randomized, single-blind study to elucidate the effect of an endotracheal tube softened with warm water before use on the incidence and severity of epistaxis following nasotracheal intubation.

METHODS

Sixty-two healthy, (ASA class I or II) patients scheduled for elective surgery were randomly assigned into two groups. Patients in the treatment group were intubated with a softened endotracheal tube made possible by heating it in warm water while those in the control group were intubated with unsoftened (intact) tube. Epistaxis was evaluated immediately after intubation and its severity was graded as none, mild, moderate and severe. The use of Magill forceps and postoperative nasal morbidity were also recorded.

RESULTS

The total incidence of epistaxis in the "unsoftened" group was significantly higher than that of "softened" group (76.7% vs. 43.8%, P = 0.0002). The severity of nasal hemorrhage was also significantly lightened in the "softened" group. No technical difficulty was encountered in intubation with a softened endotracheal tube by prewarming. The morbidity referable to nasal intubation, however, did not differ in both groups.

CONCLUSIONS

In conclusion, our study shows that using an endotracheal tube softened by warm water could reduce the incidence and severity of epistaxis during the act of nasotracheal intubation. It is an effective way and worth a try.

Prostacyclin analogue (OP-2507) attenuates hepatic microcirculatory derangement, energy depletion, and lipid peroxidation in a rat model of reperfusion injury

BACKGROUND

Microcirculatory derangement, energy depletion, and lipid peroxidation are associated with the development of ischemia-reperfusion injury in the liver. This study investigated the effects of a prostacyclin analogue (OP-2507) on hepatic ischemia-reperfusion injury.

MATERIALS AND METHODS

Adult, male Sprague-Dawley rats were divided into four treatment groups: (1) sham-operated control (laparotomy only, no ischemia), N =6; (2) ischemia control (1 h ischemia, 2 h reperfusion), N = 6; (3) intravenous infusion with OP-2507 ([15-cis-14-propylcyclohexyl]-16, 17,18,19,20-pentanor-9-deoxy-9a,6-nitrilo-PGF, methyl ether; Ono Pharmaceutical Co, Ltd, Osaka, Japan) at a dose of 1 microg/kg/min plus ischemia (1 h ischemia, 2 h reperfusion), N = 6; and (4) intravenous infusion with OP-2507 at a dose of 0.1 microg/kg/min plus ischemia (1 h ischemia, 2 h reperfusion), N = 6. A laser-Doppler flowmeter and in vivo microscopy were used to investigate hepatic microcirculation. Tissue malondialdehyde (MDA) and adenosine triphosphate (ATP) levels were determined at the end of the experiment.

RESULTS

Compared with ischemia alone, OP-2507 significantly reduced the extent of microcirculatory and hemodynamic derangement following ischemia-reperfusion. The changes of mean systolic arterial pressure (MSAP) following ischemia-reperfusion showed biphasic alterations. OP-2507 at both doses significantly attenuated decreases in MSAP. OP-2507 lessened adherent leukocyte count and improved flow velocity in the sinusoids and postsinusoidal venules. OP-2507 at the dose of 1 microg/kg/min reduced MDA (1.04 +/- 0.27 micromol/g protein vs 2.64 +/- 0.59 micromol/g protein in the ischemia and reperfusion group) and increased ATP levels (2.03 +/- 0.17 micromol/g wet wt vs 0.73 +/- 0.21 micromol/g wet wt in the ischemia and reperfusion group), while OP-2507 at a smaller dose (0. 1 microg/kg/min) had lesser but significant effects on MDA and ATP alterations.

CONCLUSION

This study demonstrates that OP-2507 treatment of ischemia can ameliorate ischemia-reperfusion injury of the rat liver.

Leukocyte-endothelial adherence correlates with pancreatic nitric oxide production in early cerulein-induced pancreatitis in rats

The role of nitric oxide (NO) in microcirculation during the development of acute pancreatitis was not clear. An in vivo microscopic technique was used for evaluating leukocyte-endothelial adherence in the pancreatic microcirculation after induction (cerulein) of acute pancreatitis. Microdialysis was performed to detect pancreatic nitrate concentration (NO level) by high-performance liquid chromatography. Cerulein caused significantly reduced flow velocity in 1 h (31 %) and increased the number of sticking leukocytes in 2 h; both persisted for at least 3 h. Pancreatic NO level was found to be significantly elevated (2.5-fold) in 1 h and also persisted for 3 h. Both microcirculatory changes and NO elevation were significantly alleviated in cerulein-induced animals pretreated with NO synthase inhibitor (NG-nitro-L-arginine), indicating that elevation of NO could precede and account for a major portion of the observed microcirculatory changes. Furthermore, there was a strong positive correlation between numbers of adherent leukocytes and pancreatic NO level, suggesting that during the development of acute pancreatitis, NO could play an adverse role in microcirculation.

Hyperbaric oxygen therapy attenuates pancreatic microcirculatory derangement and lung edema in an acute experimental pancreatitis model in rats

This study was designed to investigate hyperbaric oxygen (HBO) therapy as a treatment for managing animals with induced acute pancreatitis. Forty-five anesthetized male Sprague-Dawley rats were studied. A severe acute pancreatitis model was established by combining an intravenous infusion of cerulein (15 microg/kg/h) and an intraductal injection of 0.1 ml of glycodeoxycholic acid (5 mM). Pathology, serum amylase level, pancreatic malondiadehyde levels and water content of the lungs and the pancreas were used to evaluate the severity of disease. Moreover, an in vivo microscopic technique was used to investigate microcirculatory derangement in the pancreas, i.e., flow velocity and leukocytes sticking in postcapillary venules. HBO was delivered in three regimens, i.e., 100% oxygen at 2.5 absolute atmospheric pressure (AAP), 40% oxygen at 2.5 AAP, and 100% oxygen at 1 AAP, 6 h after the initiation of induction of acute pancreatitis. All animals survived until the end of the experiments. HBO significantly improved the pathologic conditions and pancreatic malondiadehyde levels. Concomitantly, it also significantly lessened the severity of lung edema and improved the microcirculatory environment in the pancreas. Our results support the findings that HBO therapy has a beneficial effect on pancreatic microcirculation and lung edema during acute pancreatitis in rats.

Hyperbaric oxygen pretreatment attenuates hepatic reperfusion injury

Microcirculatory derangement, energy depletion and lipid peroxidation have been related to development of ischemia-reperfusion injury in the liver. This study investigates the effects of hyperbaric oxygen (HBO) on hepatic ischemia-reperfusion injury. Adult, male Sprague-Dawley rats were used. Three groups were evaluated: 1) sham-operated control (laparotomy only, no ischemia, no HBO), n=8; 2) ischemia control (1-h ischemia, 2-h reperfusion, no HBO), n=8; and 3) HBO pretreatment (100%, oxygen, 2.5 atm absolute, 90 min) plus ischemia (1-h ischemia, 2-h reperfusion), n=8. An in vivo microscope was used to investigate hepatic microcirculation. Tissue malondialdehyde (MDA) and adenosine triphosphate (ATP) were determined. In comparison with the ischemia control group, HBO significantly improved harmful insults following ischemia-reperfusion. HBO lessened adherent leukocyte count (6.00+/-1.31 cells/200 microm vs 11.38+/-2.88 cells/200 microm), and improved flow velocity (1.72+/-0.26 mm/s vs 0.83+/-0.19 mm/s) in post-sinusoidal venules. HBO also reduced MDA (1.04+/-0.24 nmol/mg protein vs 2.24+/-0.49 micromol/g protein), and increased ATP (2.03+/-0.17 micromol/g wet wt vs 0.73+/-0.11 micromol/g wet wt) levels. This study demonstrates that HBO before ischemia may ameliorate the ischemia-reperfusion injury of the liver in the rat model.

Low-flow anesthesia in adult orthotopic liver transplantation: a preliminary clinical experience

BACKGROUND

Anesthesia in orthotopic liver transplantation (OLT) may carry with complex hemodynamic, body temperature, and metabolic alterations. Although OLT cases increased in recent years in Taiwan, experiences remained limited. Notable advantage of low flow anesthesia may include reduced consumption of anesthetic gases and vapors, reduced environmental pollution and cost-saving. This study investigated patient profiles and the feasibility of low-flow rebreathing technique for adult orthotopic liver transplantation.

METHODS

Since June 1996, there were six OLT patients who received low flow anesthesia with isoflurane. All patients received hepatic veno-venal anastmosis (so-called piggy back procedure). Two patients were excluded from this study because of different surgical procedure (total occlusion of inferior vena cava and inferior vena cava veno-venal anastmosis). During maintenance of anesthesia, isoflurane was carried by a mixture of oxygen and air at a total fresh gas flow of 0.6 L/min. Alongside with the standard anesthesia machine and physiologic monitors, a newly designed Swan-Ganz catheter was introduced to measure and record cardiac output, systemic vascular resistance, pulmonary artery pressure, central venous pressure, and core temperature in a real-time manner. Blood samples were collected at 6 predetermined time-points in each patient for analysis of arterial blood gases, electrolytes, lactate and glucose concentrations.

RESULTS

The anesthetic time was 916 +/- 26 min (900 to 930 min). All patients regained their consciousness within 30 min after completion of surgery. The hemodynamics were relatively stable except after reperfusion of the liver. There was a significant decrease in mean arterial blood pressure, which occurred with accompaniment of a reduction of systemic vascular resistance and increased cardiac output. Arterial blood gas, electrolyte, and glucose were, however, maintained within acceptable limits. Blood lactate was progressively increased and reached its peak after reperfusion of the liver until the end of surgery. The core temperature was well maintained above 34 degrees C. No patient developed hypoxia or hypercapnia.

CONCLUSIONS

Low-flow rebreathing anesthetic technique maintained acceptable patient profiles and good body temperature preservation in orthotopic liver transplantation. These characteristics make it a promising method in maintenance of anesthesia for OLT.

Propofol anesthesia in a patient with Isaacs syndrome--report of a case and literature review

Isaacs syndrome is an unusual lower motor neuron disease characterized by myokymia (muscle twitching), muscular stiffness, and decreased tendon reflexes. We reported a patient who was affected with this rare disease, with manifestation of involuntary muscular contractions and required general anesthesia for bilateral tonsillectomies. Understanding the presentation and characterization of this unusual disease may be helpful in making choice of anesthetics or anesthetic techniques. Its possible mechanisms of action and its specific considerations in anesthesia in the literature are reviewed and discussed.

Gabexate mesilate improves pancreatic microcirculation and reduces lung edema in a rat model of acute pancreatitis

We evaluated the effects of a protease inhibitor on the progression of acute pancreatitis in rats. The model was selected and modified to mimic an intermediate stage of the disease. The degree of microcirculatory derangement in the pancrease and of lung edema was determined to assess the effects of gabexate mesilate (ethyl-4-(6-guanidinohexanoyloxy) benzoate methane sulfonate), a synthetic antiprotease, in acute pancreatitis. Male Sprague-Dawley rats (225-275 g) were used. Experimental pancreatitis was established by four intramuscular injections of cerulein (50 micrograms/kg) at 1 hour intervals. Lipopolysaccharide (10 mg/kg) was injected intraperitoneally as an acute septic challenge. Gabexate mesilate was infused intravenously 6 hours after the initiation of induction of acute pancreatitis at doses of 0.01, 0.1, 1, or 10 mg/kg/h. Microcirculatory changes in the pancreas were studied using in vivo microscopy. All animals survived until the end of the experiments. Gabexate mesilate significantly improved pathologic criteria and decreased serum lipase levels at doses of 1 and 10 mg/kg/h. It significantly lessened the severity of lung edema and improved the microcirculatory environment in the pancreas by increasing flow velocity and reducing leukocyte sticking. These results indicate the beneficial effects of gabexate mesilate on pancreatic microcirculation and lung edema in the progression of acute pancreatitis with septic challenge in rats.

Propofol anesthesia increases dopamine and serotonin activities at the somatosensory cortex in rats: a microdialysis study

We sought to estimate the activities of dopamine and serotonin in animals receiving propofol anesthesia. The in vivo microdialysis technique was used in Sprague-Dawley rats (n = 6) to measure the major metabolites of dopamine and serotonin, i.e. 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (4-hydroxy-3-methyphenylacetic acid; HVA) and 5-hydroxy indole acetic acid (5-HIAA) in the somatosensory cortex. We also measured the levels of propofol in the brain and blood by microdialysis sampling in another group of rats (n = 6). During the experiment, the rat was infused intravenously (IV) with propofol at a rate of 10 mg x kg(-1) x h(-1) for 60 min and 60 mg x kg(-1) x h(-1) for 40 min. We found that IV infusion of propofol at a rate of 60 mg x kg(-1) x h(-1) significantly increased DOPAC, HVA, and 5-HIAA. We also determined that these changes correlated well with propofol levels in the brain and blood. We concluded that anesthetic doses of propofol increased the functional activities of dopamine and serotonin in the cortex. These increases correlate well with propofol levels in the cortex and blood.

Peritoneal nitric oxide is a marker of peritonitis in patients on continuous ambulatory peritoneal dialysis

Nitric oxide plays an important role in mediating the inflammatory process. The aim of this study was to evaluate if nitric oxide production was increased during peritonitis in patients receiving continuous ambulatory peritoneal dialysis (CAPD), and the association with the prognosis. The study population comprised 21 patients with 22 episodes of peritonitis. Fifteen patients without peritonitis were controls. Nitrate was measured by HPLC and nitrite by the Griess method, to reflect nitric oxide production. Peritoneal dialysate effluent and plasma were collected from six patients during peritonitis and 1 week after treatment to study changes in dialysate:plasma ratio. In 15 patients, nitrite was measured during peritonitis and every 3 days for 2 weeks or until normalized for evolutional changes. The dialysate:plasma ratios of nitrate and nitrite during peritonitis were reduced 26% and 41.5%, respectively, after 1 week of treatment, indicating the peritoneal production of nitric oxide during peritonitis. In the evolutional study, a 5.1-fold increase of peak nitrite levels in bacterial peritonitis (n = 13) and a 2.5-fold increase in fungal peritonitis (n = 3) were observed compared to controls. Nitrite gradually declined to control levels (9.3 +/- 7.2 days) after effective antibiotic treatment, but took longer than to normalize leukocyte count in the peritoneal dialysate effluent (3.9 +/- 1.9 days). In four patients with refractory peritonitis (Candida infection in three, Acinetobacter infection in one), the nitrite levels remained elevated 2-fold despite treatment, and the catheters were removed. It is concluded that nitrite levels in peritoneal dialysate effluent may serve as a marker to assess treatment efficacy in CAPD patients with peritonitis.

Participation of AT1 and AT2 receptors in the differential interaction between angiotensin II or III and alpha-2 adrenoceptors in the nucleus reticularis gigantocellularis in cardiovascular regulation and antinociception in rats

We evaluated possible interactions between angiotensin II (AII) or angiotensin III (AIII) and the alpha-2 adrenoceptors of the nucleus reticularis gigantocellularis (NRGC) in the medulla oblongata that are involved in cardiovascular regulation and antinociception, as well as the angiotensin receptor subtypes involved, using Sprague-Dawley rats that were anesthetized with pentobarbital sodium. The efficacy of guanabenz, which acts on the alpha-2 adrenoceptors in the NRGC to elicit hypotension, bradycardia and antinociception, based on tail-flick responses to noxious thermal stimuli (50 degrees C), was used as our experimental index. Bilateral microinjection of AII or AIII into the NRGC, at equimolar doses (40 pmol) that did not alter base-line systemic arterial pressure, heart rate or tail-flick latency, significantly and site-specifically attenuated the cardiovascular suppression elicited by guanabenz (100 micrograms/kg i.v.). This attenuation was appreciably antagonized by coadministration of the AT2 receptor antagonist PD-123319 (1.6 nmol). Concomitant examination of tail-flick responses revealed discernible inhibition by AII (40 pmol), but potentiation by AIII (40 pmol), of guanabenz-induced antinociception. These differential modulating effects of AII and AIII were, however, antagonized by comicroinjection of losartan (1.6 nmol) into the bilateral NRGC. Our results suggest that both AII and AIII produced a reduction, via AT2 receptors, of the activity of alpha-2 adrenoceptors in the NRGC that are involved in central cardiovascular regulation. On the other hand, antinociception induced by activation of alpha-2 adrenoceptors in the NRGC was suppressed by AII and potentiated by AIII, although AT1 receptors may play a major role in both interactions.

Video-assisted mitral valve operations

BACKGROUND

Video-assisted endoscopy has been applied frequently in the management of a variety of surgical diseases. However, it has rarely been applied in mitral valve surgery.

METHODS

We report 2 patients who received emergency operations for thrombosis of a mitral prosthesis (patient 1, a 68-year-old man) and acute mitral regurgitation due to rupture of anterior chordae (patient 2, a 75-year-old woman). They both had severe congestive heart failure. Cardiogenic shock was noted in patient 2. The mitral valve was approached through a right anterior minithoracotomy with the aid of an endoscope by means of projected images on the video monitor under femorofemoral cardiopulmonary bypass. The aorta was not cross-clamped, and the myocardium was protected by continuous coronary perfusion with hypothermic fibrillatory arrest. The left atrium was entered posterior to the interatrial groove. Thrombectomy and mitral valve repair were performed successfully.

RESULTS

The duration of extracorporeal circulation was 204 and 147 minutes, respectively. Both patients recovered from the operation rapidly with uneventful postoperative courses.

CONCLUSIONS

Our preliminary results suggest that video-assisted endoscopic cardiac surgery is technically feasible and could be performed in the milieu of open heart surgery.

Propofol anesthesia in a patient with myasthenia gravis--a case report

Experience with the use of propofol for induction and maintenance of anesthesia in patients with myasthenia gravis is limited in the literature. We report, in this case, the well prepared and successful use of continuous propofol infusion without conventional neuromuscular blocking agents in a patient with Ossermann stage IIb of myasthenia gravis undergoing laparoscopic cholecystectomy.

Effects of propofol on nociceptive response and power spectra of electroencephalographic and systemic arterial pressure signals in the rat: correlation with plasma concentration

We applied simultaneous spectral analysis of electroencephalographic (EEG) and systemic arterial pressure signals in Sprague-Dawley rats to monitor the status of consciousness and cardiovascular functions during intravenous anesthesia with propofol and to assess their correlations with plasma propofol concentration. Our results support the hypothesis that a 'threshold' plasma concentration (1.7-1.8 micrograms/ml) exists for propofol anesthesia. This threshold level, we further showed, may be attained by both i.v. bolus injection and continuous infusion, although the pharmacokinetic profiles, as well as EEG and hemodynamic correlates, may be different. Continuous, on-line power spectral analysis of EEG signals revealed that the degree of reduction in the power density of the theta and delta bands and root mean square value paralleled the level of anesthesia. Significant suppression of both alpha and beta components occurred only concomitant with EEG burst suppression. At the subanesthetic dose, i.v. infusion of propofol increased preferentially the power density of the theta and delta bands, suggesting the validity of including sedation as a nonhypnotic therapeutic application of propofol. We also found that appreciable cardiovascular suppression took place only upon anesthetic doses of propofol. Power spectral analysis of systemic arterial pressure signals indicated that this was accompanied by a progressive depression of spectral parameters that signify peripheral vascular resistance and baroreceptor reflex response.

Concentration and regional distribution of propofol in brain and spinal cord during propofol anesthesia in the rat

We evaluated the pharmacokinetics and regional distribution of propofol in the brain and spinal cord during propofol anesthesia in Sprague-Dawley rats, using high-performance liquid chromatographic determination of propofol concentration in brain, whole blood and plasma. We found that the concentration of propofol in the brain increased and decreased expeditiously during and after a 15-min and 30-min period of i.v. infusion of an anesthetic dose (60 mg/kg per h) of propofol. Furthermore, propofol was evenly distributed in the brain and spinal cord during infusion, with a significant inter-individual variation. Upon the establishment of anesthesia 15 and 30 min following intravenous infusion of propofol, the concentration of propofol in the brain, whole blood and plasma was respectively 15.7 +/- 1.9 and 39.4 +/- 2.7 micrograms/g, 4.5 +/- 1.2 and 13.6 +/- 1.3 micrograms/ml and 1.8 +/- 0.5 and 5.1 +/- 0.9 micrograms/ml (mean +/- SEM, n = 6 or 7). These high brain/blood and brain/plasma ratios during anesthesia suggest that propofol manifests a pharmacokinetic profile that is different from at least thiopental.

Power spectral analysis of the electroencephalographic and hemodynamic correlates of propofol anesthesia in the rat: intravenous infusion

Based on the tail-flick response to noxious thermal stimuli, we determined in the present study that effective antinociception could be achieved in adult male Sprague-Dawley rats 15 min after intravenous infusion of propofol at 60 mg/kg/h. Simultaneous power spectral analysis of the electroencephalographic (EEG) and systemic arterial pressure signals further revealed a concomitant depression of the activity of all EEG frequency bands (delta, theta, alpha, beta), alongside hypotension, negative inotropic and chronotropic actions, and attenuated baroreceptor reflex and vasomotor activity. These effects were congruent with a plasma concentration of propofol in the arterial blood of 1.70 +/- 0.13 micrograms/ml, as determined by high-performance liquid chromatography.

Power spectral analysis of the electroencephalographic and hemodynamic correlates of propofol anesthesia in the rat: intravenous bolus administration

Based on the tail-flick response to noxious thermal stimuli, we determined in the present study that the minimal effective antinociceptive dose of propofol in adult, male Sprague-Dawley rats, given in an intravenous bolus manner, was 10 mg/kg. Simultaneous power spectral analysis of the electroencephalographic (EEG) and systemic arterial pressure signals further revealed a concomitant transient suppression of the EEG activity, primarily in the theta and sigma bands, alongside minor hypotensive and negative inotropic and chronotropic actions, but with maintained vasomotor tone. These alterations followed a time course that paralleled the plasma concentration of propofol in the arterial blood, as detected by high-performance liquid chromatography.

Simultaneous, continuous, on-line and real-time spectral analysis of multiple physiologic signals by a personal-computer-based algorithm

We presented in this communication a computer algorithm that offers the advantage of simultaneous analysis of the power spectrum of multiple physiologic signals, including systemic arterial pressure, single-neuronal and electroencephalographic signals, on a continuous, on-line and real-time basis. It provided sensitive definition, discrimination and quantification (graphic and digital) of the various frequency components in the spectrum. There was also great flexibility in selecting the physiologic signal(s) to be analyzed, the choice of results of analysis to be displayed for each physiologic parameter and the alteration of sensitivity and baseline of each event channel. Furthermore, it included window options to improve the frequency or temporal resolution and discrimination of the spectral changes. Most importantly, all these desirable features can be accomplished economically with a general purpose personal computer.

Comparison of inguinal nerve block and intravenous fentanyl in relieving postinguinal herniorrhaphy pain for pediatric outpatients

The purpose of this study was to compare the effects of ilioinguinal/iliohypogastric (IG/IH) nerve block and intravenous fentanyl for pain control following inguinal herniorrhaphy in pediatric outpatients. Seventy-five ASA physical status I and II children (aged 1 to 10 yr) with unilateral inguinal herniorrhaphy under general anesthesia were randomly divided into three groups. Group A received IG/IH nerve block, using 0.25% bupivacaine (1 mg/kg) immediately after induction. Group B received intravenous fentanyl (1 microgram/kg) immediately after induction. Group C received only general anesthesia as control. At postanesthetic care unit (PACU), we recorded the degree of pain/or discomfort at 5, 15, 30, 45 and 60 min using modified Hannallah's scoring system after the patient was fully awake. The degree of recovery was also evaluated using Steward's scoring system. After discharge, the parents were interrogated about the condition of child within 24 h by telephone. Follow-up items raised included vomiting, drowsiness, pain and shivering. Our results showed that children in both study groups had lower pain score than those in the control group, and in the fentanyl group children had lower pain score than in the nerve block group during the first 30 min at PACU. The recovery time was also longer in the fentanyl group. There was no significant difference among the three groups regarding the raised items over telephone interrogation. In sum, inguinal nerve block was effective for postoperative pain relief in children undergoing inguinal herniorraphy. We also suggested that small dose of intravenous fentanyl would serve as an easy, simple and effective means for relieving postinguinal herniorrhaphy pain during the first 30 min of the initial postoperative period.