Evaluation of electrocardiographic ventricular repolarization parameters in extreme obesity

BACKGROUND AND OBJECTIVES

The risk of sudden death and cardiac arrhythmia increases in morbidly obese patients. We aimed to evaluate the marker of arrhythmias such as Tp-e/QT, Tp-e/QTc, Tp-e/JT and Tp-e/JTc ratios in extreme obesity.

METHODS

The study included 41 extremely obese patients and 41 control subjects. QTmax, QTmin, QRS, JT and Tp-e intervals were measured od 12‑lead electrocardiographies. In addition, Tp-e/QT, Tp-e/QTc, Tp-e/JT and Tp-e/JTc rates and QTc, cQTd and JTc intervals were calculated.

RESULTS

Tp-e interval (79.2 ± 9.7 ms (milisecond) vs. 68.6 ± 8.1, p < 0.001), QTc interval (395.9 ± 18.8 vs. 377.9 ± 19.3 ms, p < 0.001), JTc interval (317.1 ± 27.0 vs. 297.4 ± 23.2 ms, p = 0.001), Tp-e/QT ratio (0.22 ± 0.03vs. 0.19 ± 0.02, p < 0.001), Tp-e/QTc ratio (0.20 ± 0.26vs. 0.18 ± 0.02, p = 0.001), Tp-e/JT ratio (0.29 ± 0.04 vs. 0.25 ± 0.03, p < 0.001), TPe/JTc ratio (0.25 ± 0.04 vs. 0.23 ± 0.03, p = 0.018), QTd (32.8 ± 10 vs.15 ± 6.4 ms, p < 0.001) and cQTd (70.0 ± 30.1 vs. 31.3 ± 22.4 ms, p < 0.001) were significantly higher in obese patients.

CONCLUSION

Compared to healthy subjects potential ECG repolarization predictors were significantly increased in extremely obese patients.

Comparative study of ultrasound-guided paravertebral block versus intravenous tramadol for postoperative pain control in percutaneous nephrolithotomy

BACKGROUND

Percutaneous nephrolithotomy (PCNL) is a minimally invasive surgical procedure for renal calculi, and nephrostomy tubes lead to postoperative pain after PCNL. Regional techniques (e.g., epidural analgesia and peripheral blocks) and opioids are applied for postoperative pain treatment. The aim of this study was to compare effectiveness of ultrasound-guided paravertebral block (PVB) and tramadol on postoperative pain in patients who underwent PCNL.

METHOD

Fifty-three patients were included in this prospective randomized study. The patients were allocated into two groups: the PVB group (group P, n = 26) and the tramadol group (group T, n = 27). All patients were administered standard general anaesthesia. Ultrasound-guided PVB was performed at the T11- L1 levels using 0.5% bupivacaine for a total dose of 15 mL in group P. Patients in group T were intravenously administered a loading dose of 1 mg/kg tramadol. Patients in both groups were given patient-controlled analgesia. Haemodynamic parameters, visual analogue scale (VAS) scores, side effects, and complications, tramadol consumption and additional analgesic requirements of the patients were recorded after surgery.

RESULTS

Haemodynamic parameters were statistically similar between the groups. The VAS in group P were statistically lower than in group T. In the 24-h period after surgery, total PCA tramadol consumption was statistically lower in group P than in group T. The use of supplemental analgesic in group T was higher than in group P.

CONCLUSIONS

Ultrasound-guided PVB was found to be an effective analgesia compared to tramadol, and no additional complications were encountered.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02412930 , date of registration: March 27, 2015, retrospectively registered.

Preoperative informational video reduces preoperative anxiety and postoperative negative behavioral changes in children

BACKGROUND

Anesthesia and surgery can lead to major distress for children. Sedative premedication and preoperative preparation techniques are available to reduce preoperative anxiety in children. We aimed to assess the effect of informational video based on role-play modelling on preoperative anxiety and postoperative behavior changes in children undergoing surgery.

METHODS

Forty-two children aged 5-12 years, with American Society of Anesthesiologist physical status I-II, scheduled for elective outpatient surgery, were enrolled in this study. Patients were randomly allocated to one group with or without information video presentation. In group V, patients watched the information video (N.=21). Other children were verbally informed in a standard care (group C, N.=21). We recorded patient's demographics (age, birth order, surgery time, surgery type, history of previous surgery, parent's age, parental working status, parental education level), the preoperative anxiety level using Modified Yale Preoperative Anxiety Scale (MYPAS) and at 1 week after discharge, new developing postoperative maladaptive behaviors (POMB) using the Post Hospitalization Behavioral Questionnaire by telephone interview.

RESULTS

Patient's demographics were similar in both groups. Total MYPAS scores were found to be lower in group V as compared to group C P=0.0001). Difficulty getting to sleep, nocturnal enuresis, fear of dark, to object to go to bed at night and decreased appetite of new developing POMB were found to be lower in group V than group C. We also found a correlation between anxiety scores and POMB.

CONCLUSIONS

The presentation of an informational video based on model making reduces preoperative anxiety at the time of placement of the facemask and postoperative negative behavioral changes in children.

The IGF1 P2 promoter is an epigenetic QTL for circulating IGF1 and human growth

Background

Even if genetics play an important role, individual variation in stature remains unexplained at the molecular level. Indeed, genome-wide association study (GWAS) have revealed hundreds of variants that contribute to the variability of height but could explain only a limited part of it, and no single variant accounts for more than 0.3% of height variance. At the interface of genetics and environment, epigenetics contributes to phenotypic diversity. Quantifying the impact of epigenetic variation on quantitative traits, an emerging challenge in humans, has not been attempted for height. Since insulin-like growth factor 1 (IGF1) controls postnatal growth, we tested whether the CG methylation of the two promoters (P1 and P2) of the IGF1 gene is a potential epigenetic contributor to the individual variation in circulating IGF1 and stature in growing children.

Results

Child height was closely correlated with serum IGF1. The methylation of a cluster of six CGs located within the proximal part of the IGF1 P2 promoter showed a strong negative association with serum IGF1 and growth. The highest association was for CG-137 methylation, which contributed 13% to the variance of height and 10% to serum IGF1. CG methylation (studied in children undergoing surgery) was approximately 50% lower in liver and growth plates, indicating that the IGF1 promoters are tissue-differentially methylated regions (t-DMR). CG methylation was inversely correlated with the transcriptional activity of the P2 promoter in mononuclear blood cells and in transfection experiments, suggesting that the observed association of methylation with the studied traits reflects true biological causality.

Conclusions

Our observations introduce epigenetics among the individual determinants of child growth and serum IGF1. The P2 promoter of the IGF1 gene is the first epigenetic quantitative trait locus (QTL^epi) reported in humans. The CG methylation of the P2 promoter takes place among the multifactorial factors explaining the variation in human stature.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-015-0062-8) contains supplementary material, which is available to authorized users.

A novel echocardiographic method as an indicator of endothelial dysfunction in patients with coronary slow flow

BACKGROUND

To improve clinical outcomes, noninvasive imaging modalities have been proposed to measure and monitor atherosclerosis. Endothelial dysfunction is considered the first stage in the development of atherosclerosis. Brachial artery flow-mediated dilatation (FMD) has been impaired in patients with coronary slow flow (CSF). Recently, color M-mode derived propagation velocity of descending thoracic aorta (aortic propagation velocity-AVP) was shown to be an ultrasonographic marker for atherosclerosis.

AIM

To assess endothelial function in patients with CSF and the correlation of AVP with FMD.

MATERIALS AND METHODS

FMD and AVP were measured in 90 patients with CSF and 39 patients having normal coronary arteries (NCA) detected by coronary angiography.

RESULTS

Compared to patients with normal coronary arteries patients having CSF had significantly lower AVP (39.1±8.4 vs. 53.7±12.7 cm/s, p < 0.001) and FMD (5.6±3.2 vs. 17.6±4.4 %, p < 0.001) measurements. There were significant correlations between AVP and FMD (r = 0.524, p < 0.001).

CONCLUSIONS

Transthoracic echocardiographic determination of color M-mode propagation velocity of descending aorta is a simple practical method and correlates well with coronary slow flow and brachial endothelial function.

PRKAR1A and PDE4D mutations cause acrodysostosis but two distinct syndromes with or without GPCR-signaling hormone resistance

CONTEXT

Acrodysostosis is a rare skeletal dysplasia that is associated with multiple resistance to G protein-coupled receptor (GPCR) signaling hormones in a subset of patients. Acrodysostosis is genetically heterogeneous because it results from heterozygous mutations in PRKAR1A or PDE4D, two key actors in the GPCR-cAMP-protein kinase A pathway.

OBJECTIVE

Our objective was to identify the phenotypic features that distinguish the two genotypes causing acrodysostosis.

PATIENTS AND METHODS

Sixteen unrelated patients with acrodysostosis underwent a candidate-gene approach and were investigated for phenotypic features.

RESULTS

All patients had heterozygous de novo mutations. Fourteen patients carried a PRKAR1A mutation (PRKAR1A patients), five each a novel PRKAR1A mutation (p.Q285R, p.G289E, p.A328V, p.R335L, or p.Q372X), nine the reported PRKAR1A p.R368X mutation; two patients harbored a mutation in PDE4D (PDE4D patients) (one novel mutation, p.A227S; one reported, p.E590A). All PRKAR1A, but none of the PDE4D mutated patients were resistant to PTH and TSH. Two PRKAR1A patients each with a novel mutation presented a specific pattern of brachydactyly. One PDE4D patient presented with acroskyphodysplasia. Additional phenotypic differences included mental retardation in PDE4D patients. In addition, we report the presence of pigmented skin lesions in PRKAR1A and PDE4D patients, a feature not yet described in the acrodysostosis entity.

CONCLUSIONS

All PRKAR1A and PDE4D patients present similar bone dysplasia characterizing acrodysostosis. Phenotypic differences, including the presence of resistance to GPCR-cAMP signaling hormones in PRKAR1A but not PDE4D patients, indicate phenotype-genotype correlations and highlight the specific contributions of PRKAR1A and PDE4D in cAMP signaling in different tissues.

Antinociceptive activities of lidocaine and the nav1.8 blocker a803467 in diabetic rats

The streptozocin-induced diabetic rat is a model of chronic pain that shows signs of hyperalgesia and allodynia and may replicate signs in diabetic humans. Here we investigated the antinociceptive effects of A803467, a highly selective blocker of Nav1.8 channels, in diabetic rats with painful neuropathy. We systemically (intraperitoneal) or locally (intraplantar) administered A803467 (or lidocaine, a nonselective sodium channel blocker, as a control) to diabetic rats with hyperalgesia and allodynia and then measured thermal latencies and mechanical thresholds. With intraperitoneal administration, A803467 led to 6-fold greater reduction of hyperalgesia and 2-fold greater reduction of allodynia than did lidocaine. Whereas the antihyperalgesic effects of lidocaine and A803467 were similar after intraplantar administration, A803467 (1 mg) was at least 2 times more effective as an antiallodynic than was lidocaine (0.5 mg). These results suggest that compared with lidocaine, systemic or local blockade of Nav1.8 channels by A803467 may more effectively relieve hyperalgesia and allodynia in diabetic neuropathy.

Comparison of actions of systemically and locally administrated local anaesthetics in diabetic rats with painful neuropathy

Nothing is known about actions of levobupivacaine, a long-acting local anaesthetic belonging to the amino amide group, in diabetes-induced neuropathic pain conditions. In this study, we therefore investigated the possible antihyperalgesic and antiallodynic effects of levobupivacaine in diabetic animal model. Actions of systemically (intraperitoneal) or locally (intraplantar) administrated levobupivacaine on streptozotocin-induced diabetic rats with painful neuropathy were examined using a thermal plantar test and a dynamic plantar aesthesiometer. Effects of levobupivacaine were compared with those of a well-known amide local anaesthetic lidocaine. Levobupivacaine was more potent than lidocaine in all tests employed on diabetic rats. After intraperitoneal injections to diabetic rats, levobupivacaine, but not lidocaine, produced pronounced antihyperalgesic and antiallodynic effects. However, intraplantar administration of both levobupivacaine and lidocaine produced antihyperalgesic and antiallodynic action in diabetic rats. In contrast to the transient effects of lidocaine (30 min), antihyperalgesic and antiallodynic actions of levobupivacaine gradually disappeared within 120 min after intraplantar injections. Intraperitoneal or intraplantar administrations of levobupivacaine or lidocaine at the effective dose had no effect on any parameters in intact rats. Findings revealed that antiallodynic and antihyperalgesic potency of levobupivacaine was higher in comparison with that of lidocaine after their intraperitoneal or intraplantar administration to diabetic animals. Furthermore, locally administrated levobupivacaine has the greatest antihyperalgesic and antiallodynic actions in diabetic rats.

Recurrent PRKAR1A mutation in acrodysostosis with hormone resistance

The skeletal dysplasia characteristic of acrodysostosis resembles the Albright's hereditary osteodystrophy seen in patients with pseudohypoparathyroidism type 1a, but defects in the α-stimulatory subunit of the G-protein (GNAS), the cause of pseudohypoparathyroidism type 1a, are not present in patients with acrodysostosis. We report a germ-line mutation in the gene encoding PRKAR1A, the cyclic AMP (cAMP)-dependent regulatory subunit of protein kinase A, in three unrelated patients with acrodysostosis and resistance to multiple hormones. The mutated subunit impairs the protein kinase A response to stimulation by cAMP; this explains our patients' hormone resistance and the similarities of their skeletal abnormalities with those observed in patients with pseudohypoparathyroidism type 1a.

Epidural ropivacaine versus ropivacaine plus tramadol in postoperative analgesia in children undergoing major abdominal surgery: a comparison

PURPOSE

In this study, we aimed to compare the effects of ropivacaine alone and ropivacaine plus tramadol administered epidurally for postoperative analgesia in children.

METHODS

Following Ethics Committee approval and informed parent consent, 44 children aged between 2 and 12 years, with ASA physical status I or II, who were undergoing major abdominal surgery were included in the study. Following tracheal intubation, patients were placed into lateral decubitus position and an epidural catheter (22-24 G) was inserted by using a Tuohy needle. Patients were randomly divided into two groups to receive either ropivacaine alone (0.2%), 0.7 ml/kg, in group I, or ropivacaine (0.2%) plus tramadol (2 mg/kg), with total volume 0.7 ml/kg, in group II, epidurally in both groups. Hemodynamic variables, pain and sedation scores, duration of analgesia, and side effects were recorded postoperatively.

RESULTS

The duration of analgesia was significantly longer in group RT than in group R (298.6 ± 28 and 867.9 ± 106.8 min in group I and II, respectively) (P < 0.05). CHEOPS scores were significantly lower in group RT at 30 min, 45 min, and 3 h postoperatively than in group R (P < 0.05). However, sedation scores were similar between the two groups. Twenty-two patients (100%) in group R and 13 patients (59%) in group RT needed supplemental analgesia postoperatively. There were no significant differences in side effects between the groups.

CONCLUSION

In children undergoing major abdominal surgery, epidural tramadol, added to epidural ropivacaine, provided lower pain scores, longer duration of analgesia, and lower postoperative analgesic requirement.

Role of echocardiography in the evaluation of atrial function and diseases

This article describes four essential components (hemodynamic, bioelectrical, hormonal and metabolic) of atrial function. And then discusses the traditional and more recent echocardiographic measures that have been employed to evaluate atrial function. Conventional parameters include the study of the various phases of atrial activity using atrial volume measurements, the peak A wave velocity, its velocity time integral (VTI), fraction of atrial contribution and atrial ejection force. Newer parameters for atrial function assessment include Doppler tissue imaging (DTI) including segmental atrial contractility using color Doppler tissue imaging (CDTI) and estimates of atrial strain and strain rate. Furthermore, the authors relate various particular types of atrial function in physiological and in selected pathological conditions.

[Comparison of effects of nebivolol and atenolol on P-wave dispersion in patients with hypertension]

BACKGROUND

P-wave dispersion has been shown to be a noninvasive electrocardiographic predictor for development of atrial fibrillation . Thus it may be possible to attenuate atrial fibrillation risk through normalization of P-wave variables and improvement in P-wave dispersion may be an important goal in treatment of hypertension.

OBJECTIVE

To compare the effects of nebivolol, a new b-blocker that have additional vasodilating activity via acting on endothelium and nitric oxide release, and atenolol on P-wave duration and dispersion in patients with mild-to-moderate hypertension.

METHODS

A total of 34 newly-diagnosed hypertensive patients were enrolled in the study. The patients were randomly assigned to receive treatment with either nebivolol (5 mg) or atenolol (50 mg). P-wave durations (Pmin and Pmax) and P-wave dispersion were measured before and one month after treatment.

RESULTS

While Pmin increased (50,6 +/- 11,2 ms to 54,7 +/- 9,1 ms, p=0,05), Pmax decreased (111,9 +/- 9,1 ms to 104,0 +/- 12,4 ms, p=0,003) and P-wave dispersion decreased (62,5 +/- 10,6 ms to 51,3 +/- 8,9 ms, p < 0,001) with nebivolol, Pmin increased (44,4 +/- 9,8 ms to 58,0 +/- 15,5 ms, p=0,02), Pmax didn t change (106,1 +/- 13,8 ms to 107,0 +/- 11,6 ms, p=NS) and P-wave dispersion decreased (61,7 +/- 15,0 ms to 49,0 +/- 13,7 ms, p < 0.001) with atenolol. However, there was no statistical difference between pre- and post-treatment values of two groups.

CONCLUSIONS

Both nebivolol and atenolol are effective in improvement of P-wave dispersion in patients with hypertension and there s no significant difference between them.

[P wave dispersion in hypertensive urgency]

BACKGROUND AND PURPOSE

P wave dispersion (PWD) has been accepted as a predictor for atrial fibrillation (AF) in hypertension and some other cardiac diseases. The aim of this study was to compare the P wave parameters between patients with mild-moderate hypertension and those with hypertensive crises.

METHODS

A total of 48 patients, 24 of who presented to the emergency department with hypertensive urgency and 24 patients who were followed in the cardiology clinic with mild-moderate essential hypertension were included in this study. P wave durations were measured manually by two investigators blinded to data of patients.

RESULTS

The maximal duration of P wave (P max) and the PWD were found to be significantly different between groups, being longer in patients with hypertensive urgency (p=0,05 and 0,02; respectively).

CONCLUSIONS

PWD increases in hypertensive urgency states. Clinical implication of this finding should be addressed with further, prospective studies conducted on larger samples.

Role of 4-aminopyridine-sensitive potassium channels in peripheral antinociception

Previous studies has report the modulation of K+ channels play key roles in the induction of peripheral antinociception induced by many types of drugs. However, the possible participation of 4-aminopyridine-sensitive K+ channels to local antinociception induced by tramadol, a mu opioid receptor agonist, and lidocaine, a local anaesthetic, has been less studied. In this study, we therefore investigated this by using thermal plantar test. Tramadol or lidocaine administered intraplantarly into the hind paw elicited an antinociceptive effect. 4-aminopyridine caused an increase in the antinociception produced by lidocaine. However, tramadol induced antinociception remained unaffected by intraplantar administration of 4-aminopyridine. These results suggest that 4-aminopyridine-sensitive K+ channels may play an important role in the thermal peripheral antinociception produced by lidocaine, but not tramadol.

Hif-1alpha regulates differentiation of limb bud mesenchyme and joint development

Recent evidence suggests that low oxygen tension (hypoxia) may control fetal development and differentiation. A crucial mediator of the adaptive response of cells to hypoxia is the transcription factor Hif-1α. In this study, we provide evidence that mesenchymal condensations that give origin to endochondral bones are hypoxic during fetal development, and we demonstrate that Hif-1α is expressed and transcriptionally active in limb bud mesenchyme and in mesenchymal condensations. To investigate the role of Hif-1α in mesenchymal condensations and in early chondrogenesis, we conditionally inactivated Hif-1α in limb bud mesenchyme using a Prx1 promoter-driven Cre transgenic mouse. Conditional knockout of Hif-1α in limb bud mesenchyme does not impair mesenchyme condensation, but alters the formation of the cartilaginous primordia. Late hypertrophic differentiation is also affected as a result of the delay in early chondrogenesis. In addition, mutant mice show a striking impairment of joint development. Our study demonstrates a crucial, and previously unrecognized, role of Hif-1α in early chondrogenesis and joint formation.

A double-blind comparison of intrathecal S(+) ketamine and fentanyl combined with bupivacaine 0.5% for Caesarean delivery

BACKGROUND

In this prospective, randomized, double-blind, controlled study, we investigated the sensory, motor and analgesic block characteristics of S(+) ketamine, fentanyl and saline given intrathecally (IT) in addition to 0.5% plain bupivacaine (10 mg) for spinal analgesia.

METHODS

Ninety ASA I or II adult patients undergoing Caesarean section were randomly allocated to receive 1.0 mL of 0.9% saline in Group S (n = 30), 0.05 mg kg-1 of S(+) ketamine (1.0 mL) in Group K (n =30) or 25 microg (1.0 mL) of fentanyl in Group F (n =30) following 10 mg of plain bupivacaine 0.5% IT. We recorded onset and duration of sensory and motor block, time to reach the maximal dermatomal level of sensory block and duration of spinal analgesia.

RESULTS

The onset time of sensory and motor block was significantly shorter in Groups K and F than in Group S (P < 0.014). Their duration was significantly longer in Group F than in Groups K and S (P < 0.009). The time to reach the maximal dermatomal level of sensory block was significantly shorter in Groups K and F than in Group S (P < 0.001). The duration of spinal analgesia was significantly longer in Group F than in Groups K and S (P < 0.001).

CONCLUSION

In patients undergoing Caesarean section with spinal analgesia, the addition of S(+) ketamine (0.05 mg kg-1) IT to 10 mg of spinal plain bupivacaine (0.5%) led to rapid onset of both sensory and motor blockade and enhanced the segmental spread of spinal block without prolonging the duration of spinal analgesia, whereas fentanyl provided prolonged analgesia.

Local analgesic efficacy of tramadol following intraplantar injection

Several studies have suggested that systemic tramadol, an opioid, can represent a valuable treatment in severe pain conditions because of their effects on central pain pathways. However, there are not enough studies supporting that tramadol is efficacious when administered locally. Therefore, we studied the potential local analgesic effects of tramadol in peripheral nociception. In addition, we tested the antinociceptive effects of tramadol-CaCl(2) or naloxone combinations after subcutaneous intraplantar injection in a validated rat model of acute thermal nociception. Local analgesic effects of tramadol were compared with those of lidocaine. The effects of tramadol on thermal paw withdrawal latencies were monitored using the plantar test. The antinociceptive potency of tramadol is higher and long-lasting than that of lidocaine. Naloxone was unable to inhibit the increased antinociceptive response produced by tramadol. Ca(2+) modified the effect of tramadol. When Ca(2+) dose was increased in the solution, thermal antinociceptive potency of tramadol, but not lidocaine was prolonged. Thermal nociceptive responses were not affected in the non-injected paws, indicating a lack of systemic effects with doses of tramadol and lidocaine that elicited local analgesia. These results suggest that intraplantar tramadol administration can produce local analgesic effect with a different action mechanism than that of lidocaine. In addition, extracellular Ca(2+) may play an important role in the local analgesic action of tramadol.

Comparative effects of lidocaine and tramadol on injured peripheral nerves

The aim of the present study was to investigate the action of lidocaine and tramadol on the abnormal impulse characteristics of injured peripheral nerves. The ultrastructure of nerves was studied with electron microscopy and the action of lidocaine and tramadol on intact and injured rat sciatic nerves was examined by using the sucrose gap recording technique. Tramadol and lidocaine caused concentration- and frequency-dependent decreases in the amplitude of the compound action potential. Injured nerves were more sensitive to lidocaine than to tramadol. Lidocaine suppressed the delayed depolarization and decreased the hyperpolarizing afterpotentials to a greater extent than did tramadol. A low concentration of lidocaine may restore the abnormal impulse characteristics of injured nerves without changing the normal impulse pattern. The efficacy of lidocaine and inefficacy of tramadol on abnormal impulse characteristics may contribute, at least in part, to our understanding of the mechanisms of action of these drugs in neuropathic pain therapy.

Identification and characterization of the zebrafish and fugu genes encoding tuberoinfundibular peptide 39

Although the PTH type 2 receptor (PTH2R) has been isolated from mammals and zebrafish, only its mammalian agonist, tuberoinfundibular peptide 39 (TIP39), has been characterized thus far. To determine whether zebrafish TIP39 (zTIP39) functions similarly with the zebrafish PTHR (zPTH2R) and human PTH2Rs and to determine its tissue-specific expression, fugu (Takifugu rubripes) and zebrafish (Danio rerio) genomic databases were screened with human TIP39 (hTIP39) sequences. A single TIP39 gene was identified for each fish species, which showed significant homology to mammalian TIP39. Using standard molecular techniques, we isolated cDNA sequences encoding zTIP39. The fugu TIP39 precursor was encoded by a gene comprising at least three exons. It contained a hydrophobic signal sequence and a predicted prosequence with a dibasic cleavage site, similar to that found in mammalian TIP39 ligands. Phylogenetic analyses suggested that TIP39 forms the basal group from which PTH and PTHrP have been derived. Functionally, subtle differences in potency could be discerned between hTIP39 and zTIP39. The human PTH2R and zPTH2R were stimulated slightly better by both hTIP39 and zTIP39, whereas zTIP39 had a higher potency at a previously isolated zPTH2R splice variant. Whole-mount in situ hybridization of zebrafish revealed strong zTIP39 expression in the region of the hypothalamus and in the heart of 24- and 48-h-old embryos. Similarly, zPTH2R expression was highly expressed throughout the brain of 48- and 72-h-old embryos. Because the mammalian PTH2R was also most abundantly expressed in these tissues, the TIP39-PTH2R system may serve conserved physiological roles in mammals and fishes.

Comparative study of the antiemetic efficacy of ondansetron, propofol and midazolam in the early postoperative period

BACKGROUND AND OBJECTIVE

To compare the antiemetic efficacy of ondansetron with two different hypnotic drugs (propofol 15 mg, midazolam 1 and 2 mg) for the treatment of established postoperative nausea and vomiting (PONV).

METHODS

Four-hundred-and-fifty-three patients scheduled for elective gynaecological or abdominal surgery were enrolled. One-hundred-and-twenty patients (26%) experienced postoperative emesis, and when nausea scores reached 2 or greater on a five-point scale, they were randomized to receive intravenously: propofol 15 mg (1.5 mL) in Group P, midazolam 1 mg in Group M1, midazolam 2 mg in Group M2 and ondansetron 4 mg in Group O.

RESULTS

Four patients (13.3%) in Group P, 13 patients (43.3%) in Group M1, five patients (16.6%) in Group M2 and one patient (3.3%) in Group O required a second dose of the study drug. After administration of the study drugs, nausea scores were significantly lower in all groups than before these drugs were given. No patient had a sedation score over 3 (the patients remained awake and/or responded to verbal contact). The sedative effects of midazolam and propofol lasted for a much shorter time than the antiemetic effects of these drugs.

CONCLUSIONS

Propofol and midazolam used in subhypnotic doses were as effective as ondansetron in treating PONV in patients undergoing abdominal or gynaecological surgery without untoward sedative or cardiovascular effects.

Identification and characterization of two parathyroid hormone-like molecules in zebrafish

Zebrafish (Danio rerio) have receptors homologous to the human PTH (hPTH)/PTHrP receptor (PTH1R) and PTH-2 receptor (PTH2R) and an additional receptor (PTH3R) with high homology to the PTH1R. To find natural ligands for zPTH1R and zPTH3R, we searched the zebrafish genomic database and discovered two distinct regions that, when translated (zPTH1 and zPTH2), showed high homology to hPTH. Isolation of cDNAs and determination of the intron/exon boundaries revealed genomic structures which were similar to known PTHs. Peptides consisting of the first 34 amino acids after the pre- and prosequences of the zebrafish PTHs (zPTHs) were synthesized and were shown to be fully active at the hPTH1R. zPTH2(1-34) was, however, approximately 30-fold less potent at the zPTH1R than hPTH(1-34), hPTHrP(1-36), and zPTH1(1-34). When tested with zPTH3R, zPTH1(1-34) and hPTHrP(1-36) showed similar potencies, whereas the potency of zPTH2(1-34) was moderately (3-fold) reduced. To determine whether other fishes have multiple PTHs, we searched the genomic database of the Japanese pufferfish (Takifugu rubripes) and identified zPTH1 and zPTH2 homologs. Phylogenetic analysis showed that PTHs from zebrafish and pufferfish are more closely related to each other than to known mammalian PTH homologs or to PTHrP and tuberoinfundibular peptide of 39 residues. This is consistent with evolution of two teleost PTH-like peptides occurring after the evolutionary divergence between fishes and mammals. Overall, the PTH system appears more complex in fishes than in mammals, providing evidence of continued evolution in nontetrapod species. The availability of multiple forms of fish PTH and their receptors provide additional tools for PTH ligand/receptor structure-function studies.

Differential effects of lidocaine and tramadol on modified nerve impulse by 4-aminopyridine in rats

We have used the sucrose gap method to measure the effects of drugs on the electrophysiological properties of rat sciatic nerves. The results showed that 4-aminopyridine produced a slight conduction block, prolonged the duration of action potential, enhanced the hyperpolarizing afterpotential, and elicited a hump that followed the action potential. In the presence of 4-aminopyridine, the impulse-blocking activity of lidocaine and tramadol was enhanced. Both lidocaine and tramadol effectively depressed the delayed depolarization generated by 4-aminopyridine. While tramadol decreased the activity-evoked hyperpolarizing afterpotentials, lidocaine completely removed them. These findings indicate that lidocaine may be more effective in blocking the Na(+) channels than tramadol. Tramadol may be more effective on the delayed rectifier K(+) channels than lidocaine.

Comparative study of the antiemetic efficacy of ondansetron, propofol and midazolam in the early postoperative period

BACKGROUND AND OBJECTIVE

To compare the antiemetic efficacy of ondansetron with two different hypnotic drugs (propofol 15 mg, midazolam 1 and 2 mg) for the treatment of established postoperative nausea and vomiting (PONV).

METHODS

Four-hundred-and-fifty-three patients scheduled for elective gynaecological or abdominal surgery were enrolled. One-hundred-and-twenty patients (26%) experienced postoperative emesis, and when nausea scores reached 2 or greater on a five-point scale, they were randomized to receive intravenously: propofol 15 mg (1.5 mL) in Group P, midazolam 1 mg in Group M1, midazolam 2 mg in Group M2 and ondansetron 4 mg in Group O.

RESULTS

Four patients (13.3%) in Group P, 13 patients (43.3%) in Group M1, five patients (16.6%) in Group M2 and one patient (3.3%) in Group O required a second dose of the study drug. After administration of the study drugs, nausea scores were significantly lower in all groups than before these drugs were given. No patient had a sedation score over 3 (the patients remained awake and/or responded to verbal contact). The sedative effects of midazolam and propofol lasted for a much shorter time than the antiemetic effects of these drugs.

CONCLUSIONS

Propofol and midazolam used in subhypnotic doses were as effective as ondansetron in treating PONV in patients undergoing abdominal or gynaecological surgery without untoward sedative or cardiovascular effects.

Pre-emptive analgesic efficacy of tramadol compared with morphine after major abdominal surgery

BACKGROUND

Studies of pre-emptive analgesia in humans have shown conflicting results. This prospective, randomized, double-blind, controlled study was designed to test the hypothesis that a reduction in postoperative morphine consumption can be achieved by tramadol administered after induction of anaesthesia.

METHODS

Ninety patients were allocated randomly to receive i.v. tramadol (1 mg kg(-1)) (Group T), morphine (0.1 mg kg(-1)) (Group M) or saline 2 ml (Group S) after induction of anaesthesia. At peritoneal closure, a standardized (0.1 mg kg(-1)) morphine loading dose was given to all patients for postoperative pain management. Patients were allowed to use a patient-controlled analgesia (PCA) device giving bolus doses of morphine 0.025 mg kg(-1). Discomfort, sedation, pain scores, cumulative morphine consumption, and side-effects were recorded at 1, 2, 6, 12 and 24 h after the start of PCA.

RESULTS

There were no significant differences between groups in mean pain, discomfort, and sedation scores at any study period. Cumulative morphine consumption was significantly lower in Group M at 12 and 24 h after starting the PCA than in Group S. In Group T, it was lower only after 24 h (28% less in Group M and 17% less in Group T; P<0.017). There were no significant differences in morphine consumption between Groups T and M.

CONCLUSIONS

Tramadol (1 mg kg(-1)), administered after induction of anaesthesia, offered equivalent postoperative pain relief, and similar recovery times and postoperative PCA morphine consumption compared with giving morphine 0.1 mg kg(-1). These results also suggest that presurgical exposure to systemic opioid analgesia may not result in clinically significant benefits .

Effects of calcium and magnesium on peripheral nerve conduction

Divalent cations, such as calcium and magnesium, are constantly present in extracellular compartment of most organisms. Modification of extracellular concentrations of divalent ions causes changes in physiologic functions, such as excitability and conduction of the nerves. The present study was designed to investigate and compare the effects of calcium and magnesium on nerve conduction and lidocaine-induced nerve conduction block. The aim of our study was to contribute to better understanding of physiological and pharmacological roles of divalent cations. Experiments were conducted on the sciatic nerves by using the sucrose-gap recording technique. We evaluated the effects of test solutions containing different calcium or magnesium concentrations, prepared with or without lidocaine, on compound action potentials to determine physiological and pharmacological roles of these cations. After the control recordings, the nerve was exposed to Ringer's solution containing 0, 1.9, 3.8 mM Ca2+ and 1.9 and 3.8 mM Mg2+ with or without 1 mM lidocaine. Decreasing the Ca2+ concentrations in Ringer's solution with or without lidocaine enhanced both tonic and phasic blocks. However, increased Mg2+ concentration did not change the tonic blocks but increased the phasic blocks. In conclusion, the results suggested but not prove that Ca2+ and Mg2+ may have different mechanisms of action on peripheral nerves. While Ca2+ directly affects the gating of Na+ channels, action of Mg2+ can be explained by surface charge theory.

Receptor-mediated adenylyl cyclase activation through XLalpha(s), the extra-large variant of the stimulatory G protein alpha-subunit

XLalpha(s), the large variant of the stimulatory G protein alpha subunit (Gsalpha), is derived from GNAS1 through the use of an alternative first exon and promoter. Gs(alpha) and XLalpha(s) have distinct amino-terminal domains, but are identical over the carboxyl-terminal portion encoded by exons 2-13. XLalpha(s) can mimic some functions of Gs(alpha), including betagamma interaction and adenylyl cyclase stimulation. However, previous attempts to demonstrate coupling of XLalpha(s) to typically Gs-coupled receptors have not been successful. We now report the generation of murine cell lines that carry homozygous disruption of Gnas exon 2, and are therefore null for endogenous XLalpha(s) and Gs(alpha) (Gnas(E2-/E2-)). Gnas(E2-/E2-) cells transfected with plasmids encoding XLalpha(s) and different heptahelical receptors, including the beta2-adrenergic receptor and receptors for PTH, TSH, and CRF, showed agonist-mediated cAMP accumulation that was indistinguishable from that observed with cells transiently coexpressing Gs(alpha) and these receptors. Our findings thus indicate that XLalpha(s) is capable of functionally coupling to receptors that normally act via Gs(alpha).

Comparison of nerve conduction blocks by an opioid and a local anesthetic

The experiments were done on frog sciatic nerves, using a sucrose-gap recording technique. The aim of our study was to investigate and to compare the tonic and phasic conduction blocking potency of tramadol and lidocaine on whole nerve and their interactions with Ca(2+). The concentration of a tramadol solution producing the same amount of tonic and phasic conduction blocks was three and six times higher than that needed for lidocaine, respectively. Increasing the Ca(2+) concentration in the test solution enhanced the conduction blocking potency of tramadol, but decreased that of lidocaine. It is concluded that tramadol blocks nerve conduction like a local anesthetic but with a weaker effect than that of lidocaine. Interactions of Ca(2+) and these drugs suggested that these drugs might have either different binding sites or different action mechanisms.