Seguimiento por WhatsApp durante un año a pacientes con intento suicida atendidos en el Servicio de Urgencias de un hospital universitario privado / One-year follow- up to suicide attempted patients in the Emergency Department of a private hospital using WhatsApp

El suicidio como problema de salud pública mundial muestra tasas fluctuantes con tendencia a elevarse. Las estrategias en salud pública encaminadas a la reducción del intento y del reintento suicida son la principal alternativa. Objetivo: establecer la incidencia de reintento suicida, oportunidad de atención y adherencia al seguimiento de pacientes atendidos por intento suicida en el servicio de urgencias de un hospital universitario privado. Métodos y participantes: estudio de tipo cohorte prospectiva descriptiva en pacientes ≥18 años con intento suicida de riesgo bajo asignados a tratamiento psiquiátrico ambulatorio y seguido mediante la aplicación WhatsApp durante un año después del egreso. Resultados: la prevalencia de intento suicida de los pacientes que consultaron al servicio de urgencias fue de 0,38%. De 164 pacientes con intento suicida 33 ingresaron al estudio. Tenían una mediana de edad de 23 RI (25-75): 19-33 años, el 87,8% (n: 29) fueron mujeres, 42,4% (n: 22) tenía escolaridad secundaria y 63,6% (n: 21) eran del estrato socioeconómico medio. La incidencia acumulada de reintento suicida fue del 36,3% (n: 12), más frecuente al primer mes. La atención por psiquiatría más temprana fue a las dos semanas del egreso. La adherencia al seguimiento fue del 45,4%. Conclusiones: la incidencia acumulada del reintento suicida fue elevada. La oportunidad de atención y la adherencia al seguimiento fueron bajas. A pesar de los diferentes métodos hasta ahora utilizados, el seguimiento de la conducta suicida sigue siendo difícil. Se necesitan investigaciones que exploren alternativas de intervención de tipo social y comunitario.

Suicide as a global public health issue shows fluctuating rates with a tendency to increase. Public health strategies aimed to reduce suicide attempt and retry are the main alternative. Objective: establish the incidence of suicidal retry, opportunity for care and adherence to treatment in the follow-up of patients treated for suicide attempt in the emergency room of a private University hospital. Methods and participants: a descriptive prospective cohort study in patients ≥18 years of age with a low-risk suicide attempt assigned to outpatient psychiatric treatment and followed up through WhatsApp application for one year after discharge. Results: the prevalence of suicide attempt in patients who consulted the emergency room was 0.38%. Of 164 patients with a suicide attempt, 33 were low risk. With a median age of 23 IR (25-75): 19-33 years, 87.8% (n: 29) were women, 42.4% (n: 22) with secondary school level and 63.6% (n: 21) with middle socioeconomic stratum. 24.2% (n: 8). The accumulate incidence of retry was 36,3% (n: 12), more frequently in the first month. The earlier attention by psychiatry was after two weeks of discharge. The follow-up adherence was of 45,4%. Conclusions: the accumulated incidence for retry was high. The opportunity for outpatient psychiatric care and adherence to follow up were low. Despite the different methods used until now, monitoring suicidal behavior remains difficult. It is necessary research that explore alternatives for community and social intervention.

Gene expression of growth factors with angiogenic potential in human dental pulp tissue from teeth with complete and incomplete root development.

AIM: To quantify the expression of angiogenic growth factors (ANG2, VEGFA, TGFß1) and their corresponding receptors (VEGFR1, VGFR2, NRP1 and TGFßR1) in human dental pulps from extracted third molars with complete and incomplete root development. METHODOLOGY: Fifty-six dental pulp samples obtained from freshly extracted human third molars were divided equally into two groups according to their stage of root development; 28 third molars with complete root development and 28 third molars with incomplete root development. All samples were processed and total RNA was extracted, cDNA was then synthetized for each sample and the target genes expression profiles for ANG2, VEGFA, VEGFR1, VEGFR2, NRP1, TGFß1 and TGFßR1 were obtained by RT2-PCR. The data was analysed with a Student's t-test to compare the replicate ∆∆Ct values for each gene. RESULTS: Teeth with incomplete root development were associated with a significantly greater gene expression of TGFßR1 (P = 0.03), whereas in teeth with complete root development the genes that had significantly greater expression were VEGFA (P = 0.04). CONCLUSION: The angiogenic growth factors (ANG2, VEGFA, TGFß1) and their receptors (NRP1, VEGFR1, VEGFR2 and TGFßR1) were expressed in pulps of teeth with complete and incomplete root development measured by RT2-PCR, with TGFBR1 genes being significantly different in teeth with incomplete root development and VEGFA genes in teeth with complete root development.

Indicaciones de estudio urodinámico / Indications of urodynamic study

The basic objective of urodynamics is to reproduce the patient's symptoms while evaluating the lower urinary tract directly, with objective quantification of parameters, correlating the symptoms with the findings of the test. Traditionally, it is used: a) to diagnose lower urinary tract dysfunction, quantify its severity and determine the most significant abnormality, b) to predict the consequences of lower urinary tract dysfunction on the upper urinary tract, c) to predict the results of therapeutic interventions and possible complications and d) to investigate the causes of treatment failures. In this article we will refer to the indications of urodynamics taking into account the recommendations of the main international urological societies: 1) in women with urinary incontinence, with emphasis on those who have stress urinary incontinence and who will undergo surgery, 2) in men with non-neurogenic lower urinary tract symptoms suggestive of benign prostatic hyperplasia, and 3) in patients with neurologic involvement of the lower urinary tract ("neurogenic bladder"), considering the classification of neurological disorders according to the risk over the upper urinary tract. (AU)

Substance P and Calcitonin gene-related peptide expression in human periodontal ligament after root canal preparation with Reciproc Blue, WaveOne Gold, XP EndoShaper and hand files.

AIM: To quantify Substance P (SP) and Calcitonin gene-related peptide (CGRP) expression in healthy human periodontal ligament from premolars after root canal preparation with Reciproc Blue, WaveOne Gold, XP EndoShaper and hand files. METHODOLOGY: A total of 50 human periodontal ligament samples were obtained from healthy mandibular premolars where extraction was indicated for orthodontic reasons. Prior to extraction, 40 of these premolars were equally divided into four groups, and root canals were prepared using four different systems: Reciproc Blue, WaveOne Gold, XP EndoShaper and a hand instrumentation technique. The remaining 10 healthy premolars were extracted without treatment and served as a negative control group. All periodontal ligament samples were processed, and SP and CGRP were measured by radioimmunoassay. The Kruskal-Wallis test was used to establish significant differences between groups and LSD post hoc comparisons were also performed. RESULTS: Greater SP and CGRP values were found in the hand instrumentation group, followed by the XP EndoShaper, WaveOne Gold and the Reciproc groups. The lower SP and CGRP values were for the healthy periodontal ligament group. The Kruskal-Wallis test revealed significant differences between groups (P < 0.05). Post hoc Least Significant Difference (LSD) tests revealed significant differences (P < 0.05) in SP and CGRP expression between all the comparisons except for the Reciproc Blue and WaveOne Gold group (P > 0.05). CONCLUSION: All the root canal preparation techniques tested increased SP and CGRP expression in human periodontal ligament, with hand files and XP EndoShaper instruments being associated with greater neuropeptide release compared to Reciproc Blue and WaveOne Gold files.

Angiogenic mechanisms of human dental pulp and their relationship with substance P expression in response to occlusal trauma.

Angiogenesis is the formation of new blood vessels based on a pre-existing vasculature. It comprises two processes, sprouting of endothelial cells and the division of vessels due to abnormal growth of the microvasculature. It has been demonstrated that substance P (SP) can induce angiogenesis either by modulating endothelial cell growth (direct mechanism) or by attracting cells with angiogenic potential to the injury site (indirect mechanism). Therefore, the purpose of this article is to review the angiogenic mechanisms that regulate mineralized tissue formation in human dental pulp tissue and their relationship with SP expression as a defence response to stimuli such as the masticatory function and occlusal trauma. Articles included in this review were searched in PubMed, Scopus and ISI Web of Science databases, combining the following keywords: human dentine pulp, angiogenesis, angiogenic growth factors, neuropeptides, substance P, neurogenic inflammation, dentine matrix, dentinogenesis, occlusal trauma and dental occlusion. It is concluded that human dental pulp tissue responds to occlusal trauma and masticatory function with a neurogenic inflammatory phenomenon in which SP plays an important role in the direct and indirect mechanisms of angiogenesis by the action evoked via NK1 receptors at different cells, such as fibroblasts, endothelial and inflammatory cells, leading to new blood vessel formation which are needed to stimulate mineralized tissue formation as a defence mechanism.

The influence of two reciprocating single-file and two rotary-file systems on the apical extrusion of debris and its biological relationship with symptomatic apical periodontitis. A systematic review and meta-analysis.

This systematic review and meta-analysis investigated the influence of the number of files (full-sequence rotary-file versus reciprocating single-file systems) used during root canal preparation on the apical extrusion of debris and its biological relationship with the occurrence of symptomatic apical periodontitis. An extensive literature research was carried out in the Medline, ISI Web of Science and Cochrane databases, for relevant articles with the keyword search strategy. Based on inclusion and exclusion criteria, two reviewers independently rated the quality of each study determining the level of evidence of the articles selected. The primary outcome for the meta-analysis was determined by the amount of debris extruded into the periapical tissue during root canal preparation with multiple- or single-file systems in four laboratory studies. Analysis of in vivo release of neuropeptides (SP and CGRP) after root canal preparation with single- or multiple-file systems was also carried out. Amongst the 128 articles initially found, 113 were excluded for being nonrelevant or not fulfilling the selection criteria. Another four articles were excluded after methodology evaluation. Finally, nine laboratory studies and two in vivo studies were included in the systematic review. Four of the laboratory studies were further included for meta-analysis that revealed greater debris extrusion after the use of single-file techniques when compared to multiple-file systems. Analysis of in vivo neuropeptide expression in the periodontal ligament suggests that the design of the instrument is more important than the number of files used. Both rotary and reciprocating single-file systems generate apical extrusion of debris in laboratory studies, or expression of neuropeptides in vivo. Available evidence is limited, but supports the fact that this inflammatory reaction is not influenced by the number of files but the type of movement and the instrument design.

Apoptotic and autophagic cell death induced by glucolaxogenin in cervical cancer cells.

The antiproliferative and cytotoxic activity of glucolaxogenin and its ability to induce apoptosis and autophagy in cervical cancer cells are reported. We ascertained that glucolaxogenin exerts an inhibitory effect on the proliferation of HeLa, CaSki and ViBo cells in a dose-dependent manner. Analysis of DNA distribution in the cell-cycle phase of tumor cells treated with glucolaxogenin suggests that the anti-proliferative activity of this steroid is not always dependent on the cell cycle. Cytotoxic activity was evaluated by detection of the lactate dehydrogenase enzyme in supernatants from tumor cell cultures treated with the steroid. Glucolaxogenin exhibited null cytotoxic activity. With respect to the apoptotic activity, the generation of apoptotic bodies, the presence of active caspase-3 and annexin-V, as well as the DNA fragmentation observed in all tumor lines after treatment with glucolaxogenin suggests that this compound does indeed induce cell death by apoptosis. Also, a significantly increased presence of the LC3-II, LC3 and Lamp-1 proteins was evidenced with the ultrastructural existence of autophagic vacuoles in cells treated with this steroidal glycoside, indicating that glucolaxogenin also induces autophagic cell death. It is important to note that this compound showed no cytotoxic effect and did not affect the proliferative capacity of mononuclear cells obtained from normal human peripheral blood activated by phytohaemagglutinin. Thus, glucolaxogenin is a compound with anti-proliferative properties that induces programmed cell death in cancer cell lines, though it is selective with respect to normal lymphocytic cells. These findings indicate that this glycoside could have a selective action on tumor cells and, therefore, be worthy of consideration as a therapeutic candidate with anti-tumor potential.

Is there a role for cervical assessment and uterine artery Doppler in the first trimester of pregnancy as a screening test for spontaneous preterm delivery?

OBJECTIVE: To evaluate the role of cervical length (CL) and uterine artery pulsatility index (UtA-PI) at 11+0 to 13+6 weeks as predictors of spontaneous preterm delivery (sPTD) in a Chilean population. METHODS: This was a prospective study of asymptomatic women with singleton pregnancies attending for a nuchal translucency scan at 11+0 to 13+6 weeks' gestation and who underwent a transvaginal scan for evaluation of CL and UtA-PI. Exclusion criteria were fetal and pregnancy complications (other than sPTD) and iatrogenic delivery at<34 weeks. Measurements of CL and UtA-PI were adjusted for fetal crown-rump length and maternal characteristics and expressed as multiples of the median (MoM) of the unaffected group. Prediction of sPTD using maternal and pregnancy characteristics was studied using logistic regression analysis. RESULTS: A total of 3480 women were recruited into the study and, after application of exclusion criteria, 3310 were included in the analysis. The rate of sPTD at<34 weeks was 0.9% (n=31). A previous PTD had occurred in 7.4% of parous women. Patients with sPTD in the index pregnancy were characterized by a significantly higher prevalence of previous PTD (12.9% vs 3.7%, P<0.05). No significant difference was found in either CL or UtA-PI between pregnancies with and without subsequent sPTD. Logistic regression analysis showed that smoking and previous PTD were significantly associated with sPTD at<34 weeks. The combination of these characteristics provided a detection rate of 26% with a false-positive rate of 8%. CONCLUSIONS: Neither UtA-PI nor CL during the first trimester was shown to be a useful predictor of early sPTD. However, a combined model that includes smoking and previous PTD predicts approximately one-quarter of those women destined to deliver at<34 weeks, with a false-positive rate of 8%.

Intususcepción intestinal secundaria a divertículo de Meckel invaginado: reporte de un caso / Intussusception obstruction secondary for Meckel’s diverticulum invaginated: case report

INTRODUCCIÓN: La intususcepción intestinal se produce cuando un segmento de intestino y su mesenterio se invaginan en la luz de un segmento intestinal adyacente. La intususcepción constituye el 1 por ciento de todas las causas de oclusión intestinal en adultos. La mayoría de las intususcepciones ocurren en niños, presentándose sólo un 5 por ciento en el adulto. El divertículo de Meckel es la anomalía congénita más frecuente del tracto intestinal afectando al 2-3 por ciento de la población general, pero la intususcepción derivada de la invaginación de éste, es una de las causas más infrecuentes de obstrucción intestinal secundaria. PRESENTACIÓNDEL CASO: A continuación reportamos el caso de un paciente de 8 años con una obstrucción intestinal secundaria a divertículo de Meckel complicado, intervenido de urgencia con el diagnóstico intraoperatorio. DISCUSIÓN: La invaginación íleo-ileal por un divertículo de Meckel también invaginado es algo muy poco común a la edad del paciente.

INTRODUCTION: Intestinal intussusception occurs when a segment of bowel and mesentery invaginate in the light of an adjacent intestinal segment. Intussusception accounts for 1 percent of all cases of intestinal obstruction in adults. Most intussusceptions occurs in children, occurring only 5 percent in the adult. Meckel’s diverticulum is considered the most common congenital anomalies of the intestinal tract affecting 2 percent to 3 percent of the general population to be even rarer intussusception resulting from it. CASE REPORT: We report a case of an 8 years old children with a bowel obstruction secondary to complicated Meckel’s diverticulum, surgical repair with preoperative diagnosis. DISCUSSION: The ileo-ileal intussusception by an invaginated Meckel’s diverticulum is also something very uncommon for the patient’s age”.

The effect of single-file reciprocating systems on Substance P and Calcitonin gene-related peptide expression in human periodontal ligament.

AIM: To quantify the effect of two single-file reciprocating root canal preparation systems on Substance P (SP) and Calcitonin gene-related peptide (CGRP) expression in healthy human periodontal ligament (PDL). METHODOLOGY: Forty PDL samples were obtained from healthy premolars where extraction was indicated for orthodontic reasons. Prior to extraction, 20 of these premolars were divided equally in two groups, and then, root canals were prepared using one of two different single-file systems: WaveOne and Reciproc. Ten premolars were prepared with hand files and served as a positive control group. The remaining 10 premolars where extracted without treatment and served as a negative control group. All PDL samples were processed, and SP and CGRP were measured by radioimmunoassay. RESULTS: Greater SP and CGRP expression were found in the hand instrumentation group (1.220 pmol SP and 0.084 pmol CGRP per mg of PDL), followed by the WaveOne group (0.908 pmol SP and 0.046 pmol CGRP per mg of PDL) and the Reciproc group (0.511 pmol SP and 0.022 pmol CGRP per mg of PDL). The lower SP and CGRP values were associated with the intact control group (0.453 pmol SP and 0.018 pmol CGRP per mg of PDL). The Kruskal-Wallis test revealed significant differences between groups (P < 0.001). Post hoc Tukey HSD tests revealed significant differences in SP and CGRP expression between intact teeth in the control group and all the other groups (P < 0.001) except with the Reciproc group (P = 0.165 and P = 0.42 for SP and CGRP, respectively). Hand instrumentation was associated with significant differences with all the other groups (P < 0.001). Differences between the WaveOne and Reciproc groups were also significant (P < 0.001). CONCLUSION: Substance P and CGRP expression in PDL cells increased when teeth were prepared with WaveOne as well as with hand instrumentation. Reciproc maintained SP and CGRP levels in line with the negative control group.

Effect of intravenous fluid therapy on postoperative vomiting in children undergoing tonsillectomy.

BACKGROUND: Postoperative vomiting (POV) is one of the most frequent complications of tonsillectomy in children. The aim of this study was to evaluate the antiemetic effect of super-hydration with lactated Ringer's solution in children undergoing elective otorhinolaryngological surgery. METHODS: One hundred ASA I-II children, aged 1-12 yr, undergoing elective tonsillectomy, with or without adenoidectomy, under general anaesthesia were studied. Induction and maintenance of anaesthesia were standardized with fentanyl, mivacurium, and sevoflurane in N(2)O/O(2). Subjects were assigned to one of the two groups: 10 ml kg(-1) h(-1) lactated Ringer's solution or 30 ml kg(-1) h(-1) lactated Ringer's solution. A multivariable logistic regression was used for assessing the effects of super-hydration on POV (defined as the presence of retching, vomiting, or both). A value of P<0.05 was considered statistically significant. RESULTS: During the first 24 h postoperative, the incidence of POV decreased from 82% to 62% (relative reduction of 24%, P=0.026). In the adjusted logistic regression model, subjects in the 10 ml kg(-1) h(-1) group had an odds ratio of POV that was 2.92 (95% confidence interval: 1.14, 7.51) for POV compared with subjects in the 30 ml kg(-1) h(-1) group. CONCLUSIONS: Intraoperative administration of 30 ml kg(-1) h(-1) lactated Ringer's solution significantly reduced the incidence of POV during the first 24 h postoperative. Our results support the use of super-hydration during tonsillectomy, as an alternative way to decrease the risk of POV in children.

Evaluation of the effect of intravenous lidocaine on propofol requirements during total intravenous anaesthesia as measured by bispectral index.

BACKGROUND: I.V. lidocaine is increasingly used as an adjuvant during general anaesthesia. The aim of this study was to evaluate the effect of i.v. lidocaine in reducing propofol anaesthetic requirements during total i.v. anaesthesia (TIVA) maintenance and to evaluate its effect on early recovery from anaesthesia. METHODS: Forty adult patients undergoing elective laparoscopic cholecystectomy under TIVA were randomly allocated into the lidocaine group (administered 1.5 mg kg(-1) i.v. lidocaine over 5 min followed by 2 mg kg(-1) h(-1)) and the control group (administered an equal volume of saline). Propofol was administered using a target-controlled infusion to maintain the bispectral index values between 40 and 60. After surgery, all infusions were discontinued and the time to extubation was recorded. Serial arterial blood samples were drawn to assess drug plasma levels. RESULTS: The maintenance dose of propofol was significantly lower in the lidocaine group [6.00 (0.97) mg kg(-1) h(-1)] vs the control group [7.25 (1.13) mg kg(-1) h(-1); P=0.01]. Propofol plasma levels measured at the end of the infusion were 3.71 (0.89) µg ml(-1) in the lidocaine group and 3.67 (1.28) µg ml(-1) in the control group (P=0.91). The median time to extubation was longer (11.0 min; range: 10.0-21.0) in the lidocaine group vs the control group (8.3 min; range: 5.5-12.5; P=0.02). CONCLUSIONS: I.V. lidocaine reduces propofol requirements during the maintenance phase of TIVA, particularly during surgical stimulation. This sparing effect is associated with an increased time to extubation. Owing to its effect on early recovery from anaesthesia, i.v. lidocaine should be taken into account when used as a component of i.v. anaesthesia.

Preventing melasma recurrence: prescribing a maintenance regimen with an effective triple combination cream based on long-standing clinical severity.

BACKGROUND: The relapsing nature of melasma emphasizes the need to maintain efficacy achieved after acute treatment. OBJECTIVE: To compare clinical efficacy and safety of two 6-month Triple Combination (TC; containing fluocinolone acetonide, hydroquinone and tretinoin) maintenance regimens in subjects with moderate to severe melasma, after daily treatment up to 8 weeks. METHODS: This randomized, investigator-blinded, controlled study had a maintenance phase of 6 months. Sixteen centres in Brazil and Mexico enrolled 242 subjects 18 years or older attaining no or mild melasma after 8 weeks of daily TC applications. Subjects were randomized to receive TC in a twice weekly or tapering regimen [3/week (1st month), 2/week (2nd month), 1/week (4th month)]. Efficacy and safety measurements included median time to relapse and relapse-free rate, Global Severity Score, Melasma Area and Severity Index score (MASI), subject's assessment, quality of life questionnaire (MelasQol), and adverse events. RESULTS: The majority (78.8%) had no or mild melasma (GSS ≤ 1) at week 8 and entered maintenance phase. After 6 months, 53% of patients remained relapse-free with improved quality of life, and time to relapse was similar between groups (about 190 days). Melasma severity at study entry, not maintenance baseline, influenced relapse rate. The twice weekly regimen tended to show better effectiveness in postponing relapse in severe melasma. Both regimens were safe. CONCLUSIONS: After resolution of melasma with TC, maintenance therapy over 6 months was successful in preventing relapse in over half of the patients who entered maintenance phase. Prescribing medicines should be adapted to patients based on melasma severity.

Nitrous oxide (N(2)O) reduces postoperative opioid-induced hyperalgesia after remifentanil-propofol anaesthesia in humans.

BACKGROUND: The aim of this study was to test if intraoperative administration of N(2)O during propofol-remifentanil anaesthesia prevented the onset of postoperative opioid-induced hyperalgesia (OIH). METHODS: Fifty adult ASA I-II patients undergoing elective open septorhinoplasty under general anaesthesia were studied. Anaesthesia was with propofol, adjusted to bispectral index (40-50), and remifentanil (0.30 µg kg(-1) min(-1)). Patients were assigned to one of the two groups: with N(2)O (70%) and without N(2)O (100% oxygen). Mechanical pain thresholds were measured before surgery and 2 and 12-18 h after surgery. Pain measurements were performed on the arm using hand-held von Frey filaments. A non-parametric analysis of variance was used in the von Frey data analysis. P<0.05 was considered statistically significant. RESULTS: Baseline pain thresholds to mechanical stimuli were similar in both groups, with mean values of 69 [95% confidence interval (CI): 50.2, 95.1] g in the group without N(2)O and 71 (95% CI: 45.7, 112.1) g in the group with N(2)O. Postoperative pain scores and cumulative morphine consumption were similar between the groups. The analysis revealed a decrease in the threshold value in both groups. However, post hoc comparisons showed that at 12-18 h after surgery, the decrease in mechanical threshold was greater in the group without N(2)O than the group with N(2)O (post hoc analysis with Bonferroni's correction, P<0.05). CONCLUSIONS: Intraoperative 70% N(2)O administration significantly reduced postoperative OIH in patients receiving propofol-remifentanil anaesthesia.

Time-dependent analysis of extra length of stay and mortality due to ventilator-associated pneumonia in intensive-care units of ten limited-resources countries: findings of the International Nosocomial Infection Control Consortium (INICC).

Ventilator-associated pneumonias (VAPs) are a worldwide problem that significantly increases patient morbidity, mortality, and length of stay (LoS), and their effects should be estimated to account for the timing of infection. The purpose of the study was to estimate extra LoS and mortality in an intensive-care unit (ICU) due to a VAP in a cohort of 69,248 admissions followed for 283,069 days in ICUs from 10 countries. Data were arranged according to the multi-state format. Extra LoS and increased risk of death were estimated independently in each country, and their results were combined using a random-effects meta-analysis. VAP prolonged LoS by an average of 2·03 days (95% CI 1·52-2·54 days), and increased the risk of death by 14% (95% CI 2-27). The increased risk of death due to VAP was explained by confounding with patient morbidity.

Influence of obesity on propofol pharmacokinetics: derivation of a pharmacokinetic model.

BACKGROUND: The objective of this study was to develop a pharmacokinetic (PK) model to characterize the influence of obesity on propofol PK parameters. METHODS: Nineteen obese ASA II patients undergoing bariatric surgery were studied. Patients received propofol 2 mg kg(-1) bolus dose followed by a 5-20-40-120 min, 10-8-6-5 mg kg(-1) h(-1) infusion. Arterial blood samples were withdrawn at 1, 3, 5 min after induction, every 10-20 min during propofol infusion, and every 10-30 min for 2 h after stopping the propofol infusion. Arterial samples were processed by high-performance liquid chromatography. Time-concentration data profiles from this study were pooled with data from two other propofol PK studies available at http://www.opentci.org. Population PK modelling was performed using non-linear mixed effects model. RESULTS: The study involved 19 obese adults who contributed 163 observations. The pooled analysis involved 51 patients (weight 93 sd 24 kg, range 44-160 kg; age 46 sd 16 yr, range 25-81 yr; BMI 33 sd 9 kg m(-2), range 16-52 kg m(-2)). A three-compartment model was used to investigate propofol PK. An allometric size model using total body weight (TBW) was superior to all other models investigated (linear TBW, free fat mass, lean body weight, normal fat mass) for all clearance parameters. Variability in V2 and Q2 was reduced by a function showing a decrease in both parameters with age. CONCLUSIONS: We have derived a population PK model using obese and non-obese data to characterize propofol PK over a wide range of body weights. An allometric model using TBW as the size descriptor of volumes and clearances was superior to other size descriptors to characterize propofol PK in obese patients.

The effect of dentine-bonding agents on substance P release in human dental pulp.

AIM: To quantify the effect of dentine-bonding agents on Substance P (SP) release in healthy human dental pulp tissue. METHODOLOGY: Forty pulp samples were obtained from healthy pre-molars where extraction was indicated for orthodontic reasons. In thirty of these pre-molars, a standardized Class V cavity preparation was performed, and teeth were divided equally into three groups: (i) Unetched-cavity control group: Class V cavities only; (ii) Experimental Group I: 'One-step' self-etch bonding agent was placed in the cavity; and (iii) Experimental Group II: 'Two-step' total-etch bonding agent was placed in the cavity. The remaining ten healthy pre-molars where extracted without treatment and served as an intact-teeth control group. SP was measured by radioimmunoassay. RESULTS: Greater SP release was found in the 'one-step' bonding agent group, followed by the 'two-step' bonding agent group and the unetched-cavity control group. The lower SP values were for the intact-teeth control group. anova showed statistically significant differences between groups (P = 0.0001). Tukey HSD post hoc tests showed statistically significant differences in SP release between the intact-teeth control group and the three other groups (P < 0.01) and between the unetched-cavity control group and the 'one-step' bonding agent group (P < 0.05). No significant difference was found between the 'two-step' bonding agent and the unetched-cavity control group. CONCLUSION: Dentine-bonding agents placed over Class V cavity preparations increased SP release. One-step dentine-bonding agents increased SP release most.

Predictive ability of propofol effect-site concentrations during fast and slow infusion rates.

BACKGROUND: The performance of propofol effect-site pharmacokinetic models during target-controlled infusion (TCI) might be affected by propofol administration rate. This study compares the predictive ability of three effect-site pharmacokinetic models during fast and slow infusion rates, utilizing the cerebral state index (CSI) as a monitor of consciousness. METHODS: Sixteen healthy volunteers, 21-45 years of age, were randomly assigned to receive either a bolus dose of propofol 1.8 mg/kg at a rate of 1200 ml/h or an infusion of 12 mg/kg/h until 3-5 min after loss of consciousness (LOC). After spontaneous recovery of the CSI, the bolus was administered to patients who had first received the infusion and vice versa. The study was completed after spontaneous recovery of CSI following the second dose scheme. LOC was assessed and recorded when it occurred. Adequacies of model predictions during both administration schemes were assessed by comparing the effect-site concentrations estimated at the time of LOC during the bolus dose and during the infusion scheme. RESULTS: LOC occurred 0.97 +/- 0.29 min after the bolus dose and 6.77 +/- 3.82 min after beginning the infusion scheme (P<0.05). The Ce estimated with Schnider (ke0=0.45/min), Marsh (ke0=1.21/min) and Marsh (ke0=0.26/min) at LOC were 4.40 +/- 1.45, 3.55 +/- 0.64 and 1.28 +/- 0.44 microg/ml during the bolus dose and 2.81 +/- 0.61, 2.50 +/- 0.39 and 1.72 +/- 0.41 microg/ml, during the infusion scheme (P<0.05). The CSI values observed at LOC were 70 +/- 4 during the bolus dose and 71 +/- 2 during the infusion scheme (NS). CONCLUSION: Speed of infusion, within the ranges allowed by TCI pumps, significantly affects the accuracy of Ce predictions. The CSI monitor was shown to be a useful tool to predict LOC in both rapid and slow infusion schemes.

Prospective evaluation of the time to peak effect of propofol to target the effect site in children.

BACKGROUND: The plasma-effect site equilibration rate constant (k(e0)) of propofol has been determined in children with the use of the time to maximum effect (t(peak)), however, it has not been validated. The objective was to measure the t(peak;) of propofol with two depths of anesthesia monitors in children and to evaluate these measurements with a target-controlled infusion (TCI) system. METHODS: Unpremedicated, ASA I children from 3 to 11 years were studied. In Part 1, children were monitored simultaneously with the bispectral index (BIS) and the A-Line ARX-index (AAI) from the Alaris A-Line auditory-evoked potential monitor/2. The t(peak) after a bolus dose of propofol was measured. In Part 2, the t(peak) measured was used to target the effect site with a TCI system. The median (MD) and the absolute median (MDA) difference between the predicted time of peak concentration at the effect site (Ce) and the measured time of peak effect in the index of depth of anesthesia (t(error)) was used to evaluate the performance of the system. RESULTS: The BIS recordings were of a better quality than the AAI. The mean +/- standard deviation t(peak) was 65 +/- 14 s with the BIS (n=25) and 201 +/- 74 s with the AAI (n=10)(P<0.001). Validation was only performed with the BIS monitor in 40 children, yielding an MD t(error) of -9.5 s and an MDA t(error) of 10.0 s. CONCLUSIONS: The small delay between the evolution of Ce of propofol and the observed effect suggests that this can be a useful model to target the effect site in children.

Propofol consumption and recovery times after bispectral index or cerebral state index guidance of anaesthesia.

BACKGROUND: We compared the propofol requirements and recovery times when either the bispectral index (BIS) monitor or the cerebral state monitor (CSM) is used to guide propofol anaesthesia. METHODS: Forty patients undergoing laparoscopic cholecystectomy were studied. All patients were monitored with both monitors and were randomly allocated into two groups according to the monitor used to titrate propofol administration. Propofol was administered to maintain BIS or CSM within 40 and 60. Propofol consumption and clinical markers of recovery were assessed after surgery. RESULTS: In the CSM group, the values of cerebral state index (CSI) and BIS were 47 (5) and 38 (6), respectively (P=0.00054). In the BIS group, the values of CSI and BIS were 47 (5) and 45 (2), respectively (P=0.15). In the BIS group, the total amount of propofol used was lower [109 (20) microg kg(-1) min(-1)] than in the CSM group [130 (27) microg kg(-1) min(-1)] (P=0.018). The time to eye opening was lower in the BIS [7.2 (3.5) min] than in the CSM group [10.7 (6.6)] (P=0.038). There were no differences in fentanyl consumption, or in other clinical markers of recovery. CONCLUSIONS: Compared with BIS, propofol anaesthesia guided with CSI resulted in 20% higher propofol doses. This, however, does not lead to clinically relevant differences in recovery times.