Efficacy of epidural test doses?
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Adult↗
Biomedical subjects
S S Liu
Publications and source records attributed to S S Liu.
Hemodynamic responses to an epinephrine test dose in adults during epidural or combined epidural-general anesthesia.
The efficacy of an epinephrine test dose during epidural and combined epidural-general anesthesia is unknown. Thirty-two patients were randomized to receive 2% lidocaine at either a high (25 mL) or low (12 mL) thoracic level of epidural anesthesia followed by general anesthesia with 1 minimum alveolar anesthetic concentration nitrous oxide and isoflurane. A 15-micrograms epinephrine test dose was intravenously administered prior to placement of the lumbar epidural catheter, 20 min after initiation of epidural anesthesia, and after 10 min of stable end-tidal concentrations of general anesthesia. Only high thoracic levels (T-5) of epidural anesthesia reduced the peak systolic blood pressure response to epinephrine (34 +/- 17 vs 18 +/- 11 mm Hg, control versus epidural stage; P < 0.05) and reduced the peak heart rate response when combined with general anesthesia (31 +/- 11 vs 15 +/- 8 bpm; P < 0.05). Incidences of identification of intravascular injection from hemodynamic responses were similarly reduced for systolic blood pressure (100% vs 44%) and heart rate (100% vs 38%). The standard 15-micrograms epinephrine test dose is unaffected by low thoracic levels of epidural anesthesia, but may have decreased sensitivity for detection of intravascular injection during high thoracic levels of epidural anesthesia, especially during general anesthesia.
Adult↗
Hemodynamic responses to intravascular injection of epinephrine-containing epidural test doses in adults during general anesthesia.
BACKGROUND: Epidural anesthesia is sometimes initiated during general anesthesia, yet few data exist concerning efficacy of epinephrine-containing test doses. METHODS: Thirty-six patients were randomized to receive either 0.5 MAC isoflurane, 1 MAC isoflurane, or 0.5 MAC each (1 MAC total) of isoflurane and nitrous oxide. Each subject received intravenous saline followed by three test doses containing 45 mg lidocaine with 7.5, 15, and 30 micrograms epinephrine in a randomized, double-blind fashion. Heart rate and systolic, diastolic, and mean blood pressures were measured for 5 min after injection. Positive hemodynamic criteria identifying intravascular injection were determined from peak increases in hemodynamics during administration of saline. Dose-effect relationships between epinephrine and peak increases in hemodynamics were assessed with linear regression. Minimum required doses of epinephrine to produce peak positive hemodynamic increases on average were determined from linear regression. RESULTS: Positive hemodynamic criteria were identified as increases in heart rate > or = 8 beats/min, systolic blood pressure > or = 13 mmHg, diastolic blood pressure > or = 7 mmHg, and mean blood pressure > or = 9 mmHg. Significant dose-effect relationships were observed for epinephrine and peak increases in hemodynamics (correlation coefficients ranged from 0.61-0.91). Minimum required doses of epinephrine ranged from 6 to 19 micrograms depending on hemodynamic measurement and anesthetic group. CONCLUSIONS: Hemodynamic responses to intravascular injection of test doses vary with dose of epinephrine and depth and type of general anesthetic used. Thus, the 15 micrograms epinephrine contained in the standard test dose may not be sufficient during all anesthetic conditions.
Adult↗
Dose-response characteristics of spinal bupivacaine in volunteers. Clinical implications for ambulatory anesthesia.
BACKGROUND: Small doses of bupivacaine may be a reasonable choice for spinal anesthesia for patients having ambulatory surgery. However, few dose-response data are available to guide the selection of reasonable doses of bupivacaine for different ambulatory procedures. METHODS: Eight volunteers per group were randomized to receive 3.75, 7.5, or 11.25 mg of 0.75% bupivacaine with 8.25% dextrose in a double-blind manner. Sensory block was assessed with pinprick, transcutaneous electrical stimulation equivalent to surgical incision at the ankle, knee, pubis, and umbilicus, and with duration of tolerance to pneumatic thigh tourniquet. Motor block at the quadriceps and gastrocnemius muscles was assessed with isometric force dynamometry. Times until recovery from spinal anesthesia were recorded. Dose-response relationships were determined by linear regressions. Mean (95% confidence intervals) for durations of sensory and motor block per milligram of bupivacaine administered were calculated from linear regressions. RESULTS: Significant dose-response relationships (P < 0.006) were determined for sensory block, motor block, and time until recovery (R from 0.6 to 0.9). Within the range of doses studied, each additional milligram of bupivacaine was associated with an increase in duration of tolerance to transcutaneous electrical stimulation of 10 (7 to 13) min, an increase in tolerance to tourniquet of 7 (2 to 11) min, an increase in duration of motor block of 8 (5 to 12) min, and an increase in time until recovery of 21 (17 to 25) min. CONCLUSIONS: These dose-response data may guide the selection of reasonable doses of bupivacaine for various outpatient procedures, although individual responses vary.
Adult↗
Spinal meningitis masquerading as postdural puncture headache.
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Adult↗
Innovations in cranial approaches and exposures: anterolateral approaches.
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Cavernous Sinus↗
Purification of duck immunoglobulins: an evaluation of protein A and protein G affinity chromatography.
Duck serum proteins binding to protein A Sepharose CL-4B and protein G Sepharose 4 Fast Flow and eluted at pH 2.8 or 11.5 were characterized by sodium dodecyl sulphate polyacrylamide gel electrophoresis, radial/immunodiffusion against defined anti-immunoglobulin (Ig) reagents, and by the reactivity in immunoelectrophoresis of antisera raised in rabbits inoculated with the eluates. The results indicated that IgY (previous nomenclature 7.8S IgG) and IgY (delta Fc) (previously 5.7S IgG) bound to protein A efficiently and to protein G weakly, while IgM bound to protein A and protein G weakly. Some binding of non-Ig proteins also occurred. Attempts to separate the non-Ig proteins from the Igs by elution at different pHs (5.0, 4.0, 3.0 and 2.5) were unsuccessful, but it was found that precipitation of Igs in day-old duck serum with Na2SO4, followed by chromatography on protein A Sepharose, yielded relatively pure IgY. The efficient binding of the duck IgYs to protein A resembles high affinity binding of mammalian Igs but cannot be attributed to the Fc, as it is in mammals, since the IgY (delta Fc) does not have an Fc region. Instead, binding probably occurs through unique histidine residues occurring predominantly in the CH1 domain.
Amino Acid Sequence↗
Activity changes of ATP synthase and adenylate kinase in rat-liver mitochondria during the early phase after burn injury.
Using succinate as a substrate, the activities of ATP synthase and adenylate kinase in liver mitochondria of male Sprague-Dawley rats 30 min after 20 per cent full skin thickness burns were increased in comparison with the sham burn rats, suggesting that these two enzymes might contribute to the increased rates of ATP formation and oxidative phosphorylation coupling during the early phase after burn injury.
Adenylate Kinase↗
Effects of perioperative analgesic technique on rate of recovery after colon surgery.
BACKGROUND: Choice of perioperative analgesia may affect the rate of recovery of gastrointestinal function and thus duration and cost of hospitalization after colonic surgery. METHODS: Fifty-four patients undergoing partial colectomy surgery were randomized into four groups. All groups received a standardized general anesthetic. Group MB received a preoperative bolus of epidural bupivacaine and morphine followed by an infusion of morphine and bupivacaine. Group M received a preoperative bolus of epidural morphine followed by an infusion of morphine. Group B received a preoperative bolus of bupivacaine followed by an infusion of bupivacaine. Group P received a preoperative bolus of intravenous morphine followed by intravenous patient-controlled morphine postoperatively. All patients participated in a standardized recovery program to minimize the influence of nonanalgesic factors on recovery of gastrointestinal function. All epidural groups were double-blinded. All patients were deemed ready for discharge according to prospectively defined criteria. RESULTS: Groups B and MB reported superior analgesia with activity (P < 0.01). Group M had a greater incidence of pruritus (P < 0.05). Group B had a greater incidence of orthostatic hypotension (P = 0.04). Groups B and MB recovered gastrointestinal function and fulfilled discharge criteria approximately 1.5 days earlier than groups M and P (P < 0.005). CONCLUSIONS: Epidural analgesia with bupivacaine and morphine provided the best balance of analgesia and side effects while accelerating postoperative recovery of gastrointestinal function and time to fulfillment of discharge criteria after colon surgery in relatively healthy patients within the context of a multimodal recovery program.
Analgesia, Epidural↗
Detection of Y-chromosomal DNA with marker chromosomes in Turner's syndrome.
Patients with clinical features of Turner's syndrome may have a 45,X/46,X + mar or 46,X + mar karyotype. It is estimated that phenotypic females or intersexuals with a Y chromosome and gonadal dysgenesis have a 20% risk of developing gonadoblastoma, so it is crucial to know whether Turner's syndrome patients have a Y chromosome. We studied the chromosomal make-up of four patients with Turner's syndrome using the polymerase chain reaction (PCR). Nine Y-chromosomal loci including four loci (PABY, SRY, ZFY, DYS14) on the short arm, one loci (DYZ3) on the centromere, and four loci (DYS132, DYS1, DYZ1, DYZ2) on the long arm were amplified to determine the origin of marker chromosomes. Three patients were identified as having Y chromosome DNA. Patient 1 contained the presumed gonadoblastoma locus (DYS132) and a prophylactic gonadectomy was carried out. DNA extracted from dysgenetic gonads did not show Y chromosome DNA. A rapid, highly sensitive and isotope-free method for detection of abnormal Y chromosomes in Turner's syndrome patients has been developed. Chromosome in situ hybridization analysis is required to confirm the PCR results, to provide further evidence for molecular organization of these marker chromosomes.
Adult↗
[Membrane fusion between Ehrlich ascites of mastocarcinoma cells and liposome induced by proton translocation of transplasma membrane NADH-ferricyanide redox enzymes].
By using resonance energy transfer assay (RET) and fluorescence microscopy we show experimental evidence that membrane fusion of Ehrlich ascites of mastocarcinoma cells with liposomes could be induced by the proton translocation activity associated with NADH-ferricyanide redox enzyme of transplasma membrane of cancer cells. The iodoacetate, an inhibitor of glycolysis, was found to be able to depress the proton translocation activity and also to inhibit the membrane fusion. It is suggested that NADH produced mainly by glycolysis is utilized as the substrate (electron donor) for transmembrane ferricyanide reduction, and the proton pumping activity in the cancer cells is coupled to the transmembrane NADH-ferricyanide redox enzyme system. Experiments also show that membrane fusion extent of cancer cells with liposomes is proportional to the amount of H+ pumped out by the cells and membrane fusion process also exhibits a H+ consuming mode just as in fusion process of mitochondria with liposomes by redox enzyme proton pumps of respiratory chain. All of the results presented in this paper consists with recent reports of this laboratory, which indicated that various types of proton pumping system from different membrane system of cell have a new function in membrane fusion. Therefore, the proton pumping induced membrane fusion may have a more general physiological importance in triggering and modulating fusion process of native membrane in vivo.
Animals↗
HPV and p53 in cervical cancer.
OBJECTIVE: To determine the prevalence of HPV 16 and 18 E6 by DNA detection and p53 abnormal protein expression in cervical cancers in Hong Kong. MATERIALS AND METHODS: Seventy-three squamous cell cervical cancer biopsy were analysed. Detection of HPV DNA was carried out by the polymerase chain reaction and Southern blotting (PCR/SB) technique using primers to the HPV16 & 18 E6 region and consensus primers to the L1 region. Abnormal expression of the p53 protein was detected by immunohistochemical staining (IHS) using the antibody CM1 on frozen sections of 55 cervical cancer samples. Forty-six samples were analysed for both the presence of HPV DNA and abnormal expression of p53. RESULTS: 67.2% of the 64 samples showed the presence of HPV 16 E6 DNA and 39.1% showed the presence of HPV 18 E6 DNA. 32.8% showed the presence of both HPV 16 and 18 E6 DNA. No HPV DNA was shown in 10.9% of samples. Only 3.6% (2) of 55 samples showed positive IHS with CM1. One occurred in a HPV negative sample and the other in a HPV positive sample. CONCLUSION: A high prevalence of HPV DNA was detected in cervical cancer in Hong Kong using the PCR/SB technique. However, abnormal expression of p53 was uncommon amongst patients with or without HPV 16 or 18 infection.
Base Sequence↗
Anaesthetic management of a parturient with myocardial infarction related to cocaine use.
Cocaine abuse is common among parturients with an incidence of 11.8 to 20%. Myocardial infarction is a rare and lethal event during pregnancy with an incidence of 1 in 10,000 pregnancies. We present the anaesthetic management of a parturient of 36 wk gestation who suffered a myocardial infarction nine hours before delivery which was temporally related to "crack" cocaine use. The patient's cardiovascular system became unstable following cocaine use, and she required mechanical ventilatory support and pharmacologic stabilization guided by invasive haemodynamic monitoring. This patient survived a non-Q wave myocardial infarction, but the prognosis of peripartum myocardial infarction remains poor with a mortality rate of 30-40% which is increased if the infarction occurs in the third trimester or postpartum period. The optimal mode and timing of delivery after myocardial infarction is unresolved. The association between cocaine use and myocardial infarction was first described in 1982, and cocaine remains unique among local anaesthetics in its ability to compromise the cardiovascular system through both sympathomimetic effects and vasoconstrictive effects on coronary arteries. Because of the prevalence of substance abuse, cocaine use should be considered in the differential diagnosis of sudden cardiovascular compromise in parturients.
Adult↗
Lenticular uptake and distribution of xenobiotics and amino acids.
The objective of this study was to explore the relationship between lipophilicity and the lenticular uptake of radiolabeled xenobiotics. The lenticular uptake of amino acids was also investigated. An organ-culture technique was employed and the partitioning of compounds into the rabbit lens was measured for compounds with log octanol/water partition coefficients (log P o/w) ranging from -1 to 7.3. Drug distribution in the lens was expressed as the concentration ratio of that in the lenticular section (capsule/epithelium, cortex, and nucleus) to that in the incubation medium, (C(lens) section/Cm). The drug partitioning into the lens capsule was facile for all of the compounds tested. The drug concentrations in the lens capsule were higher than those in the cortical and nuclear regions. For compounds with low partition coefficients (such as sulfacetamide and cimetidine), an apparent distribution equilibrium was achieved during a 5-hr period. The C(lens)/Cm value of polar compounds, being less than one, did not further increase by prolonging the incubation period. Only compounds with log Po/w values between 3 and 6 had Cnucleus/Cm values exceeding unity. The maximal values of Ccortex/Cm and Cnucleus/Cm, approximately 15 and 4, respectively, for anthracene (log Po/w = 4.5) and diethylstilbestrol (log Po/w = 5.1), were observed in this study. A bell-shaped relationship was observed between the lenticular uptake rate and drug lipophilicity, of which the maximum occurred around log Po/w of 4. These results indicate the existence of a lipophilicity window for favorable drug distribution into the deeper region of the lens. For several lipophilic compounds, such as padimate-O, values of Cnucleus/Cm increased steadily over a 24-hour incubation period. This suggests that the nucleus behaved as a deep compartment for these compounds. L-Cysteine and L-serine were actively taken up by the lens and the lenticular absorption of L-cysteine was concentration-dependent with Vmax and Km values of 18.3 mumol/gm/hr and 49.8 mM, respectively. In summary, a relationship between lenticular uptake and drug lipophilicity was demonstrated. The optimal log Po/w value for drug uptake into the lens was between 4 and 5. The slowness of reaching significant drug concentrations in the nucleus necessitates a chronic dosing regimen to deliver therapeutic drug levels inside the lens.
Amino Acids↗
Electrolyte induced vesiculation of MA782 mice mammary adenocarcinoma ascites cells.
MA782 ascites cells were found to vesiculate when incubated in electrolyte solutions and release giant plasma membrane vesicles with diameters ranging from 5 microns to 15 microns. The vesicles, generated from the plasma membrane and free of cellular organelles, as visualized by microscopy and marker-enzyme analysis, could be proposed as a useful model membrane system.
Adenocarcinoma↗
Fusiform aneurysm after surgery for craniopharyngioma.
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Adult↗
[Serum ribonuclease in patients with malignant tumor of the ovary].
The clinical significance of serum ribonuclease (RNase) was studied in patients with malignant tumor of the ovary, and the result was compared with serum sialic acid (SA). Serum RNase and SA level were determined in 190 women consisting of 35 normal women, 34 patients with ovarian cancer, 39 patients with other malignant gynecological tumors, 38 ovarian cancer patients with clinical remission after treatment and 44 patients with benign gynecological tumor. The sensitivity of serum RNase was 82.4% in the diagnosis of malignant tumor of the ovary. Serum RNase was positive in 42.9% of patients with minimal residual tumor and 88.9% those with residual tumors greater than 2 cm in diameter. Serum RNase assay is a simple, rapid and reliable method useful in monitoring the course of disease.
Adult↗
Gastroesophageal anastomotic leakage following resection of carcinoma of the esophagus and gastric cardia: analysis of ten cases.
Postoperative anastomotic leakage is one of the most dangerous and, unfortunately, most frequent complications. Many methods have been tried to prevent such leakage. The incidence of leakage has decreased to 3.84% in our hospital in recent years. Ten cases of gastroesophageal anastomotic leakage following resection of carcinoma of the esophagus and gastric cardia are analyzed and a new tool, the three-leaf clamp, which reduced the anastomotic leakage, is introduced.
Anastomosis, Surgical↗