Comparing the efficacy of prophylactic metoclopramide, ondansetron, and placebo in cesarean section patients given epidural anesthesia.

STUDY OBJECTIVE: To compare the relative efficacy of prophylactic metoclopramide, ondansetron, and placebo in nonemergent cesarean section patients given epidural anesthesia intraoperatively and for the first 24-hour period after delivery. DESIGN: Randomized, double blind, placebo-controlled study. SETTING: Inpatient obstetric unit at a university hospital center. PATIENTS: 164 nonemergent cesarean section patients given epidural anesthesia. INTERVENTION: At time of umbilical cord clamp, patients received intravenously (IV) either 4 mg ondansetron (Group O) or 10 mg metoclopramide (Group M) or 10 mL normal saline (Group P). MEASUREMENTS AND MAIN RESULTS: Episodes and severity of nausea and vomiting, rescue antiemetic requirement, patient satisfaction, and side effects were recorded. The frequency of intraoperative nausea were 24%, 43%, and 57% for Group O, Group M, and Group P, respectively (p < 0.03). The frequency of nausea for the 24-hour study period were 26%, 51% and 71% for Groups O, M, and P respectively (p < 0.03). The frequency of intraoperative and postoperative vomiting were similar between Group O and Group M, but significantly higher in Group P (p < 0.05). Overall patient satisfaction was highest in Group O compared with Groups P and M (p < 0.05). Maximum analog sedation score was higher in Group M compared to Groups O and P (p < 0.05). CONCLUSIONS: In cesarean section patients given epidural anesthesia, prophylactic ondansetron, 4 mg IV, is more efficacious and has a higher patient satisfaction than that with metoclopramide, 10 mg IV, or placebo in preventing nausea and achieving complete responses during intraoperative period and the first 24-hour postdelivery period. However, there is no difference between ondansetron and metoclopramide in reducing frequency of vomiting. Prophylactic ondansetron 4 mg IV is more effective in preventing nausea than vomiting.

Characterization of lysozyme-estrone glucuronide conjugates. The effect of the coupling reagent on the substitution level and sites of acylation.

Estrone glucuronide conjugates of hen egg white lysozyme were prepared by the mixed anhydride and active ester coupling procedures. Both methods gave good yields of conjugates, but the active ester procedure gave a more diverse range of products, making it less suitable for preparing conjugates for homogeneous enzyme immunoassay. Conjugation of lysozyme with estrone glucuronide by the mixed anhydride procedure gave one major derivative exclusively acylated at lysine residue 33 whereas conjugation by the active ester method gave six derivatives which were acylated at one or more of lysine residues 33, 97, and 116. None of the lysine residues 1, 13, and 96, or the N-terminal alpha-amino group, were acylated in any of the conjugates isolated. The correlation of the conjugate structures with the protein environments of the amino groups in the crystal structure of lysozyme suggested that the sites of acylation were determined not only by the chemical nature of the acylating reagent but also by the surface accessibility and nucleophilicity of the individual lysine residues.

Acid-polyacrylamide gel electrophoresis of lysozyme-estrone glucuronide conjugates.

Acid-polyacrylamide gel electrophoresis (acid-PAGE) was used for analysis of lysozyme-estrone glucuronide conjugates. The resolution of the system allowed the identification of individual conjugate families which differed only in the position of acylation or in the number of estrone glucuronide units. Acid-PAGE was a good alternative to denaturing cation-exchange chromatography for the analysis, separation, and small-scale purification of lysozyme-estrone glucuronide conjugates. It revealed the true order of the relative degree of positive charge on the lysozyme-estrone glucuronide conjugates.

Antisense oligodeoxynucleotides to the kappa1 receptor enhance delta9-THC-induced antinociceptive tolerance.

Delta-9-tetrahydrocannabinol produces potent antinociceptive effects in mice and rats. Evidence exists for an interaction between the cannabinoids and the kappa receptor subtype, kappa1, in the production of antinociception. Data indicate that delta9-THC induces the release of endogenous dynorphins, the ligand(s) for the kappa receptor. It has been demonstrated that antisense oligodeoxynucleotides directed against the kappa1 receptor attenuate the antinociceptive effects of delta9-THC. The exact mechanism for the expression of cannabinoid tolerance is unknown. Bidirectional cross-tolerance between the kappa opioids and delta9-THC implies that a common mechanism may be responsible for tolerance expression. We tested the hypothesis that the kappa1 receptor is involved in tolerance to delta9-THC. Antisense to the kappa1 receptor has been shown to downregulate the kappa receptor. We observed a significant increase in the ED50 for delta9-THC in antisense-, but not mismatch-treated mice, indicating an increase in tolerance to delta9-THC. Such data indicate that a decrease in kappa receptor number may accompany tolerance to delta9-THC.

Preoperative and postoperative comparison of patients with univentricular and biventricular support with the thoratec ventricular assist device as a bridge to cardiac transplantation.

OBJECTIVES: The goal of this study was to determine whether there are differences in populations of patients with heart failure who require univentricular or biventricular circulatory support. METHODS: Two hundred thirteen patients who were in imminent risk of dying before donor heart procurement and who received Thoratec left (LVAD) and right (RVAD) ventricular assist devices at 35 hospitals were divided into three groups: group 1 (n = 74), patients adequately supported with isolated LVADs; group 2 (n = 37), patients initially receiving an LVAD and later requiring an RVAD; and group 3 (n = 102), patients who received biventricular assistance (BiVAD) from the beginning. RESULTS: There were no significant differences in any preoperative factors between the two BiVAD groups. In the combined BiVAD groups, pre-VAD cardiac index (BiVAD, 1.4 +/- 0.6 L/min per square meter, vs LVAD, 1.6 +/- 0.6 L/min per square meter) and pulmonary capillary wedge pressure (BiVAD, 27 +/- 8 mm Hg, vs LVAD, 30 +/- 8 mm Hg) were significantly lower than those in the LVAD group, and pre-VAD creatinine levels were significantly higher (BiVAD, 1.9 +/- 1.1 mg/dl, vs LVAD, 1.4 +/- 0.6 mg/dl). In addition, greater proportions of patients in the BiVAD groups required mechanical ventilation before VAD placement (60% vs 35%) and were implanted under emergency conditions than in the LVAD group (22% vs 9%). The survival of patients through heart transplantation was significantly better in patients who had an LVAD (74%) than in those who had BiVADs (58%). However, there were no significant differences in posttransplantation survival through hospital discharge (LVAD, 89%; BiVAD, 81%). CONCLUSION: Patients who received LVADs were less severely ill before the operation and consequently were more likely to survive after the operation. As the severity of illness increases, patients are more likely to require biventricular support.

Intraoperative antiemetic efficacy of prophylactic ondansetron versus droperidol for cesarean section patients under epidural anesthesia.

The efficacy of ondansetron and droperidol were evaluated for prophylactic treatment of nausea and vomiting in cesarean section patients under epidural anesthesia. Forty-eight ASA physical status I-II parturients requiring nonemergent cesarean section gave their consent and were randomly assigned into one of three treatment groups (n = 16 each) according to a double-blind, placebo-controlled protocol. When the fetal umbilical cord was clamped, patients received intravenously 8 mg of ondansetron or 0.625 mg of droperidol or saline depending on their treatment group. Ninety-four percent of the ondansetron group, 88% of the droperidol group, and 56% of the placebo group were emesis free. Sixty-nine percent of the ondansetron group, 75% of the droperidol group, and 31% of the placebo group were nausea free. This study showed a significantly lower incidence of nausea and vomiting and a tendency toward less severe emetic symptoms in the ondansetron and the droperidol groups than in the placebo group, but the ondansetron group was not statistically different from the droperidol group. This study is the first to report the antiemetic efficacy of prophylactic ondansetron in cesarean section patients or in patients under epidural anesthesia for abdominal surgery. Both prophylactic ondansetron and droperidol were similarly effective, and significantly better than placebo, in reducing the incidence and severity of intraoperative emetic symptoms in cesarean section patients under epidural anesthesia.

Involvement of enzyme-substrate charge interactions in the caseinolytic specificity of lactococcal cell envelope-associated proteinases.

Three series of oligopeptides were synthesized to investigate the proposal that a major factor in determining the differences in specificity of the lactococcal cell surface-associated proteinases against caseins is the interactions between charged amino acids in the substrate and in the enzyme. The sequences of the oligopeptides were based on two regions of kappa-casein (residues 98 to 111 and 153 to 169) which show markedly different susceptibilities to PI- and PIII-type lactococcal proteinases. In each series, one oligopeptide had an identical sequence to that of the kappa-casein region, while in the others, one or more charged residues were substituted by an amino acid of opposite charge, i.e., His<-->Glu. Generally, substitution of His by Glu in the oligopeptides corresponding to residues 98 to 111 of kappa-casein resulted in reduced cleavage of susceptible bonds by the PI-type proteinase and increased cleavage of susceptible bonds by the PIII-type proteinase. In the case of the oligopeptide corresponding to residues 153 to 169 of kappa-casein, one major cleavage site was evident, and the bond was hydrolyzed by both types of proteinase (even though this sequence in kappa-casein itself is extremely resistant to the PI-type enzyme). Substitution of Glu by His in this oligopeptide, even in the P7 position, resulted in increased cleavage of the bond by the PI-type proteinase and reduced cleavage by the PIII-type proteinase. C-terminal truncation of this oligopeptide resulted in a 100-fold decrease in the rate of hydrolysis of the susceptible bond and a change in the pattern of cleavage.(ABSTRACT TRUNCATED AT 250 WORDS)

Iron acquisition by Mycobacterium tuberculosis: isolation and characterization of a family of iron-binding exochelins.

Mycobacterium tuberculosis, the primary agent of tuberculosis, must acquire iron from the host to cause infection. To do so, it releases high-affinity iron-binding siderophores called exochelins. Exochelins are thought to transfer iron to another type of high-affinity iron-binding molecule in the bacterial cell wall, mycobactins, for subsequent utilization by the bacterium. In this paper, we describe the purification of exochelins of M. tuberculosis and their characterization by mass spectrometry. Exochelins comprise a family of molecules whose most abundant species range in mass from 744 to 800 Da in the neutral Fe(3+)-loaded state. The molecules form two 14-Da-increment series, one saturated and the other unsaturated, with the increments reflecting different numbers of CH2 groups on a side chain. These series further subdivide into serine- or threonine-containing species. The virulent M. tuberculosis Erdman strain and the avirulent M. tuberculosis H37Ra strain produce a similar set of exochelins. Based on a comparison of their tandem mass spectra, exochelins share a common core structure with mycobactins. However, exochelins are smaller than mycobactins due to a shorter alkyl side chain, and the side chain of exochelins terminates in a methyl ester. These differences render exochelins more polar than the lipophilic mycobactins and hence soluble in the aqueous extracellular milieu of the bacterium in which they bind iron in the host.

Identification of alcaligin as the siderophore produced by Bordetella pertussis and B. bronchiseptica.

The siderophores produced by iron-starved Bordetella pertussis and B. bronchiseptica were purified and were found to be identical. Using mass spectrometry and proton nuclear magnetic resonance, we determined that the siderophore produced by these organisms was identical to alcaligin, a siderophore produced by Alcaligenes denitrificans.

Experimental design in health care.

Design of experiments (DOE) is a collection of statistically based methods for testing multiple process improvement ideas after a quality improvement team has made initial improvements to remove defects and stabilize the process. Although experimental design techniques are not new, their use in improving administrative processes has not been fully exploited. Anderson Area Medical Center, located in Anderson, South Carolina, used classical quality improvement methods and DOE to significantly decrease patient dissatisfaction with emergency room services from an average of 27 percent to 6 percent.

Purification and crystallization of the endoglycosidase PNGase F, a peptide:N-glycosidase from Flavobacterium meningosepticum.

The endoglycosidase peptide: N-glycosidase, secreted by the Gram-negative bacterium Flavobacterium meningosepticum (PNGase F), has been isolated, purified to homogeneity and crystallized from polyethylene glycol solutions using vapour diffusion and seeding techniques. The crystals are orthorhombic, space group P2(1)2(1)2, with unit cell dimensions a = 85.07 A, b = 85.14 A, c = 48.50 A, and are suitable for high resolution X-ray structure analysis.

Plasma concentration profile of epidural alfentanil. Bolus followed by continuous infusion technique in the parturient: effect of epidural alfentanil and fentanyl on fetal heart rate.

BACKGROUND AND OBJECTIVES: A combined bolus and continuous epidural infusion technique of opioid and bupivacaine mixture has been described, although no pharmacokinetic data for this technique exists. The study documents the plasma concentration profile of epidural alfentanil in parturients using this technique, and evaluates the fetal heart rate tracing for associated changes following opioid administration. METHODS: Twenty-four subjects were randomized to receive epidural alfentanil 500 micrograms in 10 mL 0.125% bupivacaine, group A, or fentanyl 50 micrograms in 10 mL 0.125% bupivacaine, group B, as a bolus dose, followed by continuous infusions of alfentanil 20 micrograms/mL in 0.125% bupivacaine (group A) or fentanyl 2 micrograms/mL in 0.125% bupivacaine (group B) for labor analgesia. Plasma drug levels for each group were examined using repeated measures analysis of covariance. RESULTS: Fetal heart rate tracings were recorded throughout the study and were retrospectively analyzed by a "blinded" perinatologist. Data from fetal heart rate tracings were examined by repeated measures analysis of variance. Mean infusion rates were 9.3 +/- 2.1 mL/hour and 9.6 +/- 1.7 mL/hour for groups A and B, respectively. Mean study duration was 3.7 hours in group A, and 3.0 hours in group B. Low plasma levels precluded analysis of fentanyl data. Group A subjects exhibited stability of drug levels over time. Fetal heart rate tracings in 21 patients demonstrated no changes associated with epidural opioid infusion in either group. CONCLUSIONS: With the dosage regimen used in this study, an initial epidural bolus with continuous infusion technique generates a steady state plasma concentration of alfentanil that is below levels associated with direct respiratory depression.

Solution structure of the variant-3 neurotoxin from Centruroides sculpturatus Ewing.

The solution structure of the CsE-v3 neurotoxin from the venom of the North American scorpion Centruroides sculpturatus Ewing (CsE) has been determined by a hybrid refinement procedure that employed distance geometry and dynamical simulated annealing. Distance constraints deduced from the nuclear Overhauser effect spectroscopy data and torsion angle constraints deduced from the vicinal coupling constant data were used in the refinement procedure. A family of simulated annealing structures that showed no constraint violations was generated. The energy-minimized average structure exhibited root-mean-square deviations of 0.121 nm for the backbone and 0.182 nm for all atoms, with respect to this family. These studies confirm the previously qualitative NMR findings about the secondary structural features, viz. the presence of a short alpha-helix composed of residues 23-31 and an antiparallel beta-sheet composed of the strands of residues 1-5, 45-50 and 36-42. A cluster of aromatic ring systems is located on one side of the protein. The solution and crystal structures have similar overall features, but show some minor differences.

The primary structure of phosphofructokinase from Lactococcus lactis.

The primary amino acid sequence of phosphofructokinase (EC2.7.1.11) from Lactococcus lactis, obtained by Edman analysis of peptides obtained from proteolytic digestions, is MKRIAVLTSGGDAPGMNAAIRAVVRKAISEGIEVYGINHGYAGMVAGDIF PLTSASVGDKIGRGGTFLYSARYPEFAQVEGQLAGIEQLKKFGIEGVVVI GGDGSYHGAMRLTEHGFPAVGLPGTIDNDIVGTDFTIGFDTAVSTVVDAL DKIRDTSSSHNRTFVVEVMGRNAGDIALNAGIAAGADDISIPELEFKFEN VVNNINKGYEKGKNHHIIIVAEGVMTGEEFATKLKEAGYKGDLRVSVLGH IQRGGSPTARDRVLASRMGARAVELLRDGIGGVAVGIRNEELVESPILGT AEEGALFSLTTEGGIKVNNPHKAGLELYRLNSALNNLNL.

The addition of epinephrine to subarachnoid administered hyperbaric bupivacaine with fentanyl for cesarean delivery: the effect on onset time.

BACKGROUND AND OBJECTIVES: This study examines the effect of epinephrine on the time to achieve a T4 sensory level when added to a hyperbaric bupivacaine-fentanyl mixture for spinal anesthesia. METHODS: Sixty-nine healthy parturients scheduled for elective cesarean delivery were randomly assigned to three groups. All patients were given 9 mg hyperbaric 0.75% bupivacaine with 25 micrograms fentanyl. Group 1 received no epinephrine while Groups 2 and 3 received 100 micrograms and 200 micrograms epinephrine, respectively. Injection of the spinal anesthetic solutions was performed with the patient in the sitting position. Immediately after drug administration, patients were placed supine with their heads elevated on a pillow and 15 degrees of left uterine displacement was maintained. Vital signs and sensory levels were obtained every minute for 10 minutes. RESULTS: In Groups 2 and 3, the mean time to T4 sensory level was significantly longer (6.9 minutes and 6.6 minutes, respectively) than in Group 1 (4.6 minutes). As a subset, patients weighing more than 90.8 kg achieved a T4 sensory level faster than did those weighting less than 90.8 kg (3 minutes and 5.1 minutes, respectively), but in both groups epinephrine prolonged the onset time to T4 (5.8 minutes and 7.3 minutes, respectively). Three patients were excluded because of failure to obtain a T4 sensory level. CONCLUSIONS: The onset time to T4 is related inversely to patient weight, and epinephrine (100 micrograms and 200 micrograms) delays the onset of sensory block to T4 when administered with subarachnoid hyperbaric bupivacaine-fentanyl.

Non-pulsatile circulatory support in 90 cases.

Survival after cardiac arrest is reportably less than 10%; after cardiogenic shock it is less than 50%; and in failure to wean post-cardiotomy (even with centrifugal pumps in several large series) it is only 11-21%. The authors' experience with non-pulsatile circulatory support in 90 consecutive cases from 1986-91 has shown improved survival. The emergent cardiopulmonary bypass system (CPS) was used in 67 of the 90 patients, with 65 patients resuscitated, 34 (51%) weaned, and 19 (28%) transferred to other cardiovascular support therapies. Of the patients weaned or transferred, 34 (51%) survived > 24 hr, and 21 (31%) survived > 30 days. In the current series, 108 major cardiovascular procedures were done during or after CPS implementation. An in-house trained nursing team working with surgeons and perfusionists contributed to early implementation of the CPS and the subsequent improved survival. The BioMedicus centrifugal pump (VAD) was used predominantly for post-cardiotomy failure to wean in 16 patients and as a bridge to transplant in 7 patients. Fourteen patients (61%) were weaned or transplanted. Of these 14 patients, 11 (48%) survived > 30 days. Non-pulsatile circulatory support devices are relatively inexpensive and available to most hospitals. With careful patient selection and early implementation, one can expect survival of 37% of patients who would otherwise not survive.

Successful mechanical circulatory support for noncoronary shock.

Mechanically assisted recovery from shock and long-term survival of nontransplant patients with acute noncoronary myocardial decompensation have not been previously reported. We treated nine patients (aged 8 to 53 years) who were referred with acute nonischemic cardiogenic shock (pulmonary capillary wedge greater than 20, cardiac index less than 1.5 L/min/m2, mean blood pressure less than 60 mm Hg, ejection fraction less than 0.3%). Eight patients had viral prodromes, and one patient was peripartum. All patients' lungs were mechanically ventilated, and pharmacologic support failed in all patients. Two patients received steroids. All received mechanical circulatory support. Seven were initially supported with intraaortic balloon counterpulsation pumps. Two patients recovered with intraaortic balloon counterpulsation pumps alone (3 days and 4 days). Four patients received left ventricular assist devices (3, 7, 10, and 79 days), and two received biventricular support devices (10 days and 14 days). One patient was supported with extracorporeal femoral vein-to-femoral artery bypass for 6 days. Four patients required dialysis (4 days to 5 weeks). Seven patients underwent myocardial biopsies, of which three demonstrated acute myocarditis. All patients recovered ventricular function (ejection fraction greater than 0.55%), and all are New York Heart Association functional class I, 7 months to 4 1/2 years after support. Mechanical circulatory assist devices may be lifesaving for patients with acute nonischemic myocardial decompensation. Patients should be supported for at least 2 weeks before transplantation is considered.

Comparison of bovine beta-casein hydrolysis by PI and PIII-type proteinases from Lactococcus lactis subsp. cremoris [corrected].

The action of the cell-wall-associated proteinases from Lactococcus lactis subsp. cremoris strains H2 and SK112 on bovine beta-casein was compared. The proteinase from the H2 strain was characterised as a PI-type proteinase since it did not hydrolyse alpha s1-casein and the initial trifluoroacetic acid-soluble products of beta-casein hydrolysis were identical to those previously identified as hydrolysis products of PI-type lactococcal proteinase action. The time-course of product formation by the proteinase from the H2 strain indicated that the bonds Tyr193-Gln194 and Gln182-Arg183 were the first to be hydrolysed. Cleavage of the bonds Gln175-Lys176, Ser168-Lys169, Ser166-Gln167 and Leu163-Ser164 was also very rapid. Four of the five bonds in beta-casein most susceptible to hydrolysis by the PIII-type proteinase from strain SK112 were different from those cleaved by the PI-type proteinase, initial hydrolysis being at the sites Tyr193-Gln194, Leu192-Tyr193, Asp43-Glu44, Gln46-Asp47 and Phe52-Ala53. Early hydrolysis at the three sites in the N-terminal region of beta-casein, leading to cleavage of the N-terminal phosphopeptide and rapid precipitation of the residual fragment, represents a marked contrast to the action of PI-type proteinases where cleavage at sites in the N-terminal region occurs only very slowly.

Experience and directions using cardiopulmonary support in fifty-three consecutive cases.

Emergency cardiopulmonary support (CPS) was instituted in 53 consecutive patients for acute life threatening pathologies. Indications for CPS deployment were: cardiac arrest, 60% (n = 32); cardiogenic shock, 20.4% (n = 11), supported angioplasty, 13% (n = 7); and adult respiratory distress syndrome, 5.6% (n = 3). Cardiopulmonary support was successfully deployed in 51 of the 53 patients (96%), resulting in a mean blood pressure greater than or equal to 60 mmHg, CO greater than or equal to 3-5 L/min, and partial pressure of oxygen greater than or equal to 100 mmHg, with venous oxygen saturation greater than or equal to 60%. The average time from arrest to CPS deployment was 40 minutes. Seventy-nine major cardiovascular procedures were done in these 51 patients (average, 1.5/patient). The duration of support ranged from 1 to 75 hrs (mean, 16.1 hrs). Twenty-seven patients (53%) were weaned, 13 successfully (32%), with 11 (85%) surviving greater than 24 hrs, and six (46%), greater than 30 days. The other 24 patients (47%) were transferred to other treatment modalities, including cardiac surgery and bridge-to-transplant ventricular assist devices. Four of these patients died (17%), whereas 20 (83%) survived. Of these survivors, 19 (95%) survived greater than 24 hrs, whereas 11 (55%) survived greater than 30 days. The overall survival using the CPS system is 59% short-term (greater than 24 hrs.), and 33% long-term (greater than 30 days). In conclusion, the CPS system is a potent and effective resuscitative tool. It requires transfer to other treatment modalities for survival in most cases.

Action of a cell wall proteinase from Lactococcus lactis subsp. cremoris SK11 on bovine alpha s1-casein.

The cell wall-associated proteinase from Lactococcus lactis subsp. cremoris SK11 was partially purified and incubated with alpha s1-casein for various times up to 48 h. Sixteen trifluoroacetic acid-soluble oligopeptide hydrolysis products were identified by determination of the amino acid sequence. Eleven of these oligopeptides originated from the 78-residue sequence comprising the C-terminal region of alpha s1-casein and were present among the products after the first 60 min of digestion. Three oligopeptides from the N-terminal region and two others from the central region of the alpha s1-casein sequence were also present among the early digestion products although in smaller amounts than most of the oligopeptides from the C-terminal region. No clear consensus sequence of amino acid residues surrounding the cleavage sites could be identified.