Abstract P011: B cell subsets that correlate with anti-PD-1 resistance in a preclinical model of HPV+ oropharyngeal cancer

A subset of head and neck squamous cell carcinomas (HNSCC) is associated with infection with oncogenic strains of human papillomavirus (HPV) and its prevalence continues to rise in the US. Cancer progression has been associated, in part, with an impaired immunity. Because of this, immunotherapies such as immune checkpoint blockade (ICB) have been FDA approved to treat different types of cancers, including HNSCC. The ICB targeting the molecule programmed death cell-1 (PD-1) is used as treatment for HPV-related HNSCC, however, only around 30% of patients respond. Most studies have focused on characterizing T cell responses, however, B cells, are also present in the tumor microenvironment of HPV-positive HNSCC. Interestingly, different B cell subsets with differential functions that may promote or prevent an effective anti-tumor response are present in tumors and tumor-draining lymph nodes. Therefore, fine regulation of anti-tumor and tumor-promoting B cell subsets may be necessary to promote an effective anti-tumor response and therefore prevent tumor progression. However, the B cells that may be associated with responsiveness to anti-PD-1 in HPV+ oropharyngeal cancer remain undefined. By using the preclinical model for HPV+ oropharyngeal cancer (named mEER) we have determined that tongue-implanted tumors are sensitive to anti-PD-1, where around 50% of the mice clear the tumors, whereas flank-implanted tumors are completely resistant to these treatments. By using this in vivo model, we were able to characterize B cell subsets in anti-PD-1 sensitive and anti-PD-1 resistant tumors. First, we compared B cell subsets in untreated mice between tongue (anti-PD-1 sensitive) and flank-implanted (anti-PD-1 resistant) tumors by flow cytometry. Interestingly, flank-implanted tumors contained more PD-1-expressing B cells, which have been identified as an immunosuppressive population in hepatocellular carcinoma. The presence of immunosuppressive B cells on flank tumors was also supported by our finding that flank implanted tumors grew at a slower rate in B cell-deficient mice compared to wild-type mice. When we compared tongue-bearing tumor mice that responded or not responded to anti-PD-1, we observed that mice that did not respond to anti-PD-1 had a higher frequency of antibody-secreting cells in tumor-draining lymph nodes compared to responders. Lastly, when we cultured naïve B cells with tumor cell supernatant from mEER cells, B cells upregulated PD-1 and were able to produce the immunosuppressive cytokine IL-10. Our data suggest that HPV+ oropharyngeal tumors modulate B cell functions and that a differential infiltration of B cell subsets into tumors and tumor-draining lymph nodes correlates with responsiveness to anti-PD-1 therapy in a preclinical model of HPV+ oropharyngeal cancer. These results will aid in our long-term goal to elucidate novel mechanisms for the modulation of anti-tumor responses by B cells and the development of novel B cell-specific therapies for HPV-related cancers and, therefore, improve clinical outcomes in these patients.

Citation Format: Pamela A. Merheb, Daniel L. Castañón, Michael Rivera, Jorge Galán, Stephanie M. Dorta-Estremera. B cell subsets that correlate with anti-PD-1 resistance in a preclinical model of HPV+ oropharyngeal cancer [abstract]. In: Abstracts: AACR Virtual Special Conference: Tumor Immunology and Immunotherapy; 2021 Oct 5-6. Philadelphia (PA): AACR; Cancer Immunol Res 2022;10(1 Suppl):Abstract nr P011.

Guidelines for enhanced recovery after cardiac surgery. Consensus document of Spanish Societies of Anesthesia (SEDAR), Cardiovascular Surgery (SECCE) and Perfusionists (AEP)

The ERAS guidelines are intended to identify, disseminate and promote the implementation of the best, scientific evidence-based actions to decrease variability in clinical practice. The implementation of these practices in the global clinical process will promote better outcomes and the shortening of hospital and critical care unit stays, thereby resulting in a reduction in costs and in greater efficiency. After completing a systematic review at each of the points of the perioperative process in cardiac surgery, recommendations have been developed based on the best scientific evidence currently available with the consensus of the scientific societies involved.

Investigation of the role of typhoid toxin in acute typhoid fever in a human challenge model

Salmonella Typhi is a human host-restricted pathogen that is responsible for typhoid fever in approximately 10.9 million people annually¹. The typhoid toxin is postulated to have a central role in disease pathogenesis, the establishment of chronic infection and human host restriction^2–6. However, its precise role in typhoid disease in humans is not fully defined. We studied the role of typhoid toxin in acute infection using a randomized, double-blind S. Typhi human challenge model⁷. Forty healthy volunteers were randomized (1:1) to oral challenge with 10⁴ colony-forming units of wild-type or an isogenic typhoid toxin deletion mutant (TN) of S. Typhi. We observed no significant difference in the rate of typhoid infection (fever ≥38 °C for ≥12 h and/or S. Typhi bacteremia) between participants challenged with wild-type or TN S. Typhi (15 out of 21 (71%) versus 15 out of 19 (79%); P = 0.58). The duration of bacteremia was significantly longer in participants challenged with the TN strain compared with wild-type (47.6 hours (28.9–97.0) versus 30.3(3.6–49.4); P ≤ 0.001). The clinical syndrome was otherwise indistinguishable between wild-type and TN groups. These data suggest that the typhoid toxin is not required for infection and the development of early typhoid fever symptoms within the context of a human challenge model. Further clinical data are required to assess the role of typhoid toxin in severe disease or the establishment of bacterial carriage.

Typhoid toxin is not essential for the pathogenesis of typhoid fever in healthy humans challenged with Salmonella Typhi.

Micromegas for dark matter searches: CAST/IAXO & TREX-DM experiments

The most compelling candidates for Dark Matter to day are WIMPs and axions. The applicability of gasesous Time Projection Chambers (TPCs) with Micromesh Gas Structures (Micromegas) to the search of these particles is explored within this work. Both particles would produce an extremely low rate at very low energies in particle detectors. Micromegas detectors can provide both low background rates and low energy threshold, due to the high granularity, radiopurity and uniformity of the readout. Small (few cm wide) Micromegas detectors are used to image the axion-induced x-ray signal expected in the CERN Axion Solar Telescope (CAST) experiment. We show the background levels obtained in CAST and the prospects to further reduce them to the values required by the Internation Axion Observatory (IAXO). We also present TREX-DM, a scaled-up version of the Micromegas used in axion research, but this time dedicated to the low-mass WIMP detection. TREX-DM is a high-pressure Micromegas-based TPC designed to host a few hundreds of grams of light nuclei (argon or neon) with energy thresholds potentially at the level of 100 eV. The detector is described in detail, as well as the results of the commissioning and characterization phase on surface. Besides, the background model of TREX-DM is presented, along with the anticipated sensitivity of this search, which could go beyond current experimental limits.

Dye adsorption onto mesoporous materials: pH influence, kinetics and equilibrium in buffered and saline media

Mesoporous materials were used as adsorbents for dye removal in different media: non-ionic, buffered and saline. The mesoporous materials used were commercial (silica gel) as well as as-synthesised materials (SBA-15 and a novel mesoporous carbon). Dye adsorption onto all the materials was very fast and the equilibrium was reached before 1 h. The pH has a significant influence on the adsorption capacity for the siliceous materials since the electrostatic interactions are the driving forces. However, the influence of the pH on the adsorption capacity of the carbonaceous material was lower, since the van der Waals interactions are the driving forces. The ionic strength has a great impact on the siliceous materials adsorption capacity, being their adsorption capacity in a buffered medium six times higher than the corresponding to a non-ionic medium. Nevertheless, ionic strength does not influence on the dye adsorption on the mesoporous carbon. Overall, the as-synthesised carbon material presents a clear potential to treat dye effluents, showing high adsorption capacity (q(e) ≈ 200 mg/g) in all the pH range studied (from 3 to 11); even at low concentrations (C(e) ≈ 10 mg/L) and at short contact times (t(e) < 30 min).

[Perioperative management of atrial fibrillation]

Atrial fibrillation is a frequent complication in the perioperative period. When it appears there is an increased risk of perioperative morbidity due to stroke, thromboembolism, cardiac arrest, myocardial infarction, anticoagulation haemorrhage, and hospital readmissions. The current article focuses on the recommendations for the management of perioperative atrial fibrillation based on the latest Clinical Practice Guidelines on atrial fibrillation by the European Society of Cardiology and the Spanish Society of Cardiology. This article pays special attention to the preoperative management, as well as to the acute perioperative episode. For this reason, the latest recommendations for the control of cardiac frequency, antiarrhythmic treatment and anticoagulation are included.

Search for solar axions by the CERN axion solar telescope with 3He buffer gas: closing the hot dark matter gap

The CERN Axion Solar Telescope has finished its search for solar axions with (3)He buffer gas, covering the search range 0.64 eV ≲ ma ≲ 1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with it. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of gaγ ≲ 3.3 × 10(-10)  GeV(-1) at 95% C.L., with the exact value depending on the pressure setting. Future direct solar axion searches will focus on increasing the sensitivity to smaller values of gaγ, for example by the currently discussed next generation helioscope International AXion Observatory.

[Fondaparinux as an alternative anticoagulant in heparin-induced thrombocytopenia in the patient with a ventricular assist device]

Heparin-induced thrombocytopenia is a reaction associated with the use of this drug. It occurs in up to 3% of patients treated for at least 5 days. Its treatment is to stop the heparin, and according to patient needs, replace it with another anticoagulant. We present a patient who, after a heart transplant, and the need for a ventricular assist device, required anticoagulation. The patient developed heparin-induced thrombocytopenia. Heparin was stopped and anticoagulation was replaced by fondaparinux. The peri-operative complications and the management of the coagulation are described.

Anxiety as a marker of severity in acute mania

OBJECTIVE

Anxiety has scarcely been studied in acute mania. The aim of this study was to assess anxiety symptoms during manic episodes and their impact on clinical outcomes.

METHOD

Observational, cross-sectional multicentre study. Anxiety was measured using the Hamilton Anxiety Rating Scale (HARS). Bivariate and multiple linear regression analyses were performed using the HARS score as the dependent variable.

RESULTS

Two hundred and forty-two patients admitted with a diagnosis of acute manic episode according to DSM-IV TR criteria and a Young Mania Rating Scale>20 were analysed. Mean age was 43 years (SD=11.9) and 57% were women. Forty-six per cent of patients (n=104) presented moderate to severe anxiety symptoms (HARS score>14). Anxiety was significantly associated with severity of manic symptoms (P<0.0001). Patients with anxiety had 20% longer hospitalizations (mean 21 days, CI95% 19.7-23.7).

CONCLUSION

An association of anxiety symptoms with greater severity in acute mania was demonstrated. The close relationship between anxiety and manic symptoms highlights the need for greater clinical attention to anxiety in this population. Further studies are necessary to determine whether effective treatment of anxiety symptoms could improve clinical and care outcomes.

Benchmarking in the process of donation after brain death: a methodology to identify best performer hospitals

A benchmarking approach was developed in Spain to identify and spread critical success factors in the process of donation after brain death. This paper describes the methodology to identify the best performer hospitals in the period 2003-2007 with 106 hospitals throughout the country participating in the project. The process of donation after brain death was structured into three phases: referral of possible donors after brain death (DBD) to critical care units (CCUs) from outside units, management of possible DBDs within the CCUs and obtaining consent for organ donation. Indicators to assess performance in each phase were constructed and the factors influencing these indicators were studied to ensure that comparable groups of hospitals could be established. Availability of neurosurgery and CCU resources had a positive impact on the referral of possible DBDs to CCUs and those hospitals with fewer annual potential DBDs more frequently achieved 100% consent rates. Hospitals were grouped into each subprocess according to influencing factors. Hospitals with the best results were identified for each phase and hospital group. The subsequent study of their practices will lead to the identification of critical factors for success, which implemented in an adapted way should fortunately lead to increasing organ availability.

Continuously evaluating performance in deceased donation: the Spanish quality assurance program

The Spanish Quality Assurance Program applied to the process of donation after brain death entails an internal stage consisting of a continuous clinical chart review of deaths in critical care units (CCUs) performed by transplant coordinators and periodical external audits to selected centers. This paper describes the methodology and provides the most relevant results of this program, with information analyzed from 206,345 CCU deaths. According to the internal audit, 2.3% of hospital deaths and 12.4% of CCU deaths in Spain yield potential donors (clinical criteria consistent with brain death). Out of the potential donors, 54.6% become actual donors, 26% are lost due to medical unsuitability, 13.3% due to refusals to donation, 3.1% due to maintenance problems and 3% due to other reasons. Although the national pool of potential donors after brain death has progressively decreased from 65.2 per million population (pmp) in 2001 to 49 pmp in 2010, the number of actual donors after brain death has remained at about 30 pmp. External audits reveal that the number of actual donors could be 21.6% higher if all potential donors were identified and preventable losses avoided. We encourage other countries to develop similar comprehensive approaches to deceased donation performance.

Search for sub-eV mass solar axions by the CERN Axion Solar Telescope with 3He buffer gas

The CERN Axion Solar Telescope (CAST) has extended its search for solar axions by using (3)He as a buffer gas. At T=1.8 K this allows for larger pressure settings and hence sensitivity to higher axion masses than our previous measurements with (4)He. With about 1 h of data taking at each of 252 different pressure settings we have scanned the axion mass range 0.39 eV≲m(a)≲0.64 eV. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of g(aγ)≲2.3×10(-10) GeV(-1) at 95% C.L., the exact value depending on the pressure setting. Kim-Shifman-Vainshtein-Zakharov axions are excluded at the upper end of our mass range, the first time ever for any solar axion search. In the future we will extend our search to m(a)≲1.15 eV, comfortably overlapping with cosmological hot dark matter bounds.

Análisis retrospectivo de las historias clínicas de una clínica veterinaria en Bogotá

Se presenta un análisis de la base de datos de historias médicas de una clínica veterinaria ubicada en la ciudad de Bogotá, Colombia, con el propósito de establecer el orden de importancia de las distintas patologías diagnosticadas en los perros desde la perspectiva de su frecuencia, edad de presentación, razas afectadas y género. El estudio abarca 72.248 registros, realizados entre los años 1994 y 2004. Los procesos que afectan piel y tegumentos representaron el 24,5% de la casuística estudiada, las patologías gastroentéricas el 13,2%, las infestaciones por distintos tipos de parásitos el 7,9% y los diagnósticos odontológicos el 7,1%. Las dos razas más prevalentes son el Labrador retriever con un 23,2% y el French poodle con un 18%, lo cual significa que entre ellas constituyen el 41,2% de las razas atendidas en consulta. Aún cuando el presente trabajo, dadas las características de la metodología utilizada y sobre todo del tipo de muestra, no constituye necesariamente un reflejo exacto de lo que acontece en la ciudad en términos de patologías que afectan a los perros, si es un primer referente y la muestra estudiada es amplia en número de casos y tiempo de observación.

Does multiorgan donation influence survival in heart transplantation?

Current heart transplant survival in Spain at 1, 5, and 10 years is 80%, 70%, and 60%, respectively. Our objective was to establish how donor type affects survival in heart transplantation.

MATERIALS AND METHODS

This was a retrospective study of heart transplant recipients from 102 donors, divided into three types: (a) heart-liver-kidney donors (group I); (b) heart-liver-kidney-lung donors (group II); and (c) heart-liver-kidney-lung-pancreas donors (group III). We excluded retransplantations, pediatric transplantations, and cardiopulmonary transplantations. The outcome variable was the actuarial survival by type of donation. Statistical analysis was performed for event-free survival based on the Kaplan-Meier method (log-rank test).

RESULTS

Groups I, II, and III included 63, 26, and 13 donors, respectively. The survival curves showed similar values for all three groups (P > .05).

CONCLUSIONS

The different combinations of multiorgan donation do not entail a poorer prognosis in terms of cardiac transplant patient survival.

Study on Health-Related Quality of Life in Patients With Advanced Heart Failure Before and After Transplantation

Our objective was to evaluate health-related quality of life in patients with advanced heart failure on the waiting list for a heart transplant.

MATERIALS AND METHODS

The study was performed using the EUROQOL-5D questionnaire (EQ-5D) on 38 patients (age: 53 +/- 2 years, 82% men) who were analyzed consecutively during the pretransplant period, as well as at 3, 6, and 12 months after transplantation. We excluded pediatric transplants, retransplantations, heart and lung transplantation, and patients scoring below 17 points on the Folstein's Cognitive Mini-Examination. The studied variables included the five dimensions of the EQ-5D test: mobility, self-care, daily activities, pain-discomfort, anxiety and depression; a visual analog scale from 0 to 100; and perception of health status. Statistics included analysis of variance and chi-square tests. Significance was set at P < .05.

RESULTS

There were significant differences in all tested parameters. The worst values were observed prior to transplantation, with a significant improvement at 3 months.

CONCLUSIONS

Patients with heart failure showed a significant impairment in health-related quality of life before transplantation. The improvement in health-related quality of life was significant and rapidly evident in the posttransplantation period. The most affected dimensions were activities of daily living and pain-discomfort. All dimensions became stable at 3 months, except for anxiety and depression. At 6 to 12 months, a plateau was reached in the feelings of well-being.

Study of the Evolution of the Clinical Profile of Heart Donors

Certain characteristics of the donor have implications for the early and late survival of transplants. The trends show a progressive worsening in the clinical profile of heart donors. Our objective was to analyze changes in the clinical characteristics of donors.

MATERIALS AND METHODS

This retrospective study of 396 donors was divided into three periods: 1990 to 1994, 1995 to 1999, and 2000 to 2004. We excluded combination transplantations, retransplantations, and pediatric transplantations. The donor variables included age, cause of death, cardiorespiratory arrest, ICU stay, and ischemia time. Statistical analysis used ANOVA, Kruskall-Wallis, and Chi square test, with significance set at P < .05.

RESULTS

Differences were found in age (1990-1994: 27 +/- 1, 1995-1999: 29 +/- 1, 2000- 2004: 34 +/- 1 years; P = .0001), ischemia time (1990-1994: 119 +/- 6, 1995-1999: 145 +/- 4, 2000-2004: 156 +/- 4 minutes; P = .0001), and death from brain hemorrhage (1990-1994: 28%, 1995-1999: 31%, 2000-2004: 43%; P = .031).

CONCLUSIONS

There were differences in the clinical characteristics of the donors in the study periods. The age of the donor, stroke-related deaths, and ischemia time have increased significantly in recent years.

[Risk factors for acute respiratory failure after liver transplantation]

OBJECTIVES

To study the risk factors for acute respiratory failure during recovery after liver transplantation.

PATIENTS AND METHODS

We prospectively studied 340 consecutive liver transplant operations. Patient data was grouped according to whether acute respiratory failure developed (group I) or not (group II). Acute respiratory failure was defined by the need for mechanical ventilation longer than 5 days after transplantation or by the need for an inspired oxygen fraction of over 50% for 72 hours. We evaluated demographic characteristics, stage of liver disease before the transplant, comorbidity, immunosuppressant treatment administered, and complications during and after surgery.

RESULTS

Sixty-six patients were placed in group I and 274 in group II. Univariate analysis showed significant differences between the groups for age, sex, Child-Pugh functional stage, preoperative renal failure, type of immunosuppression, and postoperative complications such as atrial fibrillation, pleural effusion, pulmonary edema, ascites, postoperative acute renal failure, brain dysfunction, early graft dysfunction, and respiratory infection. Multivariate analysis by logistic regression, taking the development or not of acute respiratory failure as the dependent variable, gave a model with 6 variables that accounted for 94% of the cases. The variables entering into the model, with their respective odds ratios (OR) were female sex (OR, 5.5), stage C liver function (OR, 3.9), pulmonary edema (OR, 16.3), postoperative acute renal failure (OR, 9), cerebral dysfunction (OR, 4.5), and respiratory infection (OR, 62).

CONCLUSIONS

The development of acute respiratory failure after liver transplantation is affected by the following factors: female sex, Child-Pugh class, pulmonary edema, postoperative acute renal failure, cerebral dysfunction, and respiratory infection.

Repression of rac2 mRNA expression by Anaplasma phagocytophila is essential to the inhibition of superoxide production and bacterial proliferation

Anaplasma phagocytophila, the etiologic agent of human granulocytic ehrlichiosis, is an emerging bacterial pathogen that invades neutrophils and can be cultivated in HL-60 cells. Infected neutrophils and HL-60 cells fail to produce superoxide anion (O(2)(-)), which is partially attributable to the fact that A. phagocytophila inhibits transcription of gp91(phox), an integral component of NADPH oxidase. cDNA microarray and RT-PCR analyses demonstrated that transcription of the gene encoding Rac2, a key component in NADPH oxidase activation, was down-regulated in infected HL-60 cells. Quantitative RT-PCR demonstrated that rac2 mRNA expression was reduced 7-fold in retinoic acid-differentiated HL-60 cells and 50-fold in neutrophils following A. phagocytophila infection. Rac2 protein expression was absent in infected HL-60 cells. Rac1 and Rac2 are interchangeable in their abilities to activate NADPH oxidase. HL-60 cells transfected to express myc-tagged rac1 and gp91(phox) from the CMV immediate early promoter maintained the ability to generate O(2)(-) 120 h postinfection. A. phagocytophila proliferation was severely inhibited in these cells. These results directly attribute the inhibition of rac2 and gp91(phox) transcription to the loss of NADPH oxidase activity in A. phagocytophila-infected cells and demonstrate its importance to bacterial intracellular survival.

Tightly regulated gene expression system in Salmonella enterica serovar Typhimurium

A new Salmonella enterica serovar Typhimurium strain has been constructed to facilitate tightly regulated gene expression. Arabinose-inducible and glucose-repressible expression of a T7 RNA polymerase gene that has been integrated with an adjacent araC-P(BAD) control element into the bacterial chromosome allows dynamic control of T7 promoter-driven RNA transcription.

Stability and bifurcations of the figure-8 solution of the three-body problem

The stability properties of a recently discovered solution of the general three-body problem with equal masses and the shape of a figure 8 are analyzed as the masses are varied. It is shown by numerical continuation and the evaluation of the characteristic multipliers that the solution is stable only in a narrow mass interval. Other less symmetrical and unstable solutions with equal masses in the same homotopy class as the figure-8 orbit have been found. The branching behavior is also analyzed.

Salmonella entry into host cells: the work in concert of type III secreted effector proteins

Upon contact with intestinal epithelial cells, Salmonella enterica serovar spp. inject a set of bacterial proteins into host cells via the bacterial SPI-1 type III secretion system. SopE, SopE2 and SopB, activate CDC42 and Rac to initiate actin cytoskeleton rearrangements. SipA and SipC, two Salmonella actin-binding proteins, directly modulate host actin dynamics to facilitate bacterial uptake. SptP promotes the recovery of the actin cytoskeleton rearrangements by antagonizing CDC42 and Rac. Therefore, Salmonella-induced reversible actin cytoskeleton rearrangements are the result of two coordinated steps: (i) stimulation of host signal transduction to indirectly promote actin rearrangements and (ii) direct modulation of actin dynamics.

Dynamical mean-field solution of coupled quantum wells: a bifurcation analysis

The time evolution of a discrete model of three quantum wells with a localized mean-field electrostatic interaction has been analyzed making use of numerical simulation and bifurcation techniques. The discrete Schrödinger equation can be written as a classical Hamiltonian system with two constants of motion. The frequency spectrum and the Lyapunov exponents show that the system is chaotic as its continuum counterpart. The organizing centers of the dynamical behavior are bifurcations of rotating periodic solutions whose simple structure allows a thorough analytical investigation as the conserved quantities are varied. The global structure of the periodic behavior is organized via subharmonic bifurcations at which tori of nonsymmetric periodic solutions are born. We have found another kind of bifurcation when two pairs of characteristic multipliers split from the unit circle. The chaotic behavior is related to the nonintegrability of the system.

[Comparison of an auditory evoked potentials index and a bispectral index versus clinical signs for determining the depth of anesthesia produced by propofol or sevoflurane]

OBJECTIVES

To evaluate an anesthetic depth index (ADI) obtained from auditory evoked potentials and a bispectral EEG index (BIS) in comparison with clinical assessment of anesthetic depth using the modified observer's assessment of awareness/sedation scale (MOAA/SS), for induction of anesthesia with propofol or sevoflurane as the only agent.

PATIENTS AND METHODS

The ADI and BIS were recorded simultaneously in this prospective study and compared to the MOAA/SS during the anesthetic induction of 26 adults undergoing elective heart surgery. Assignment of patients to two groups was random. Group A (n = 13) patients were induced with propofol (target dose 5 micrograms.ml-1 in 5 min). Induction in group B (n = 13) was with sevoflurane (8% tidal volume). A scheme of awake-sleeping-awake-sleeping was followed. The means of the two indexes were compared (Mann-Whitney test) one minute before the patient slept (awake) and one minute later (sleeping), and the evolution of the indexes was compared during awake/sleep and sleep/awake phase changes and while the patients were in a stable sleep phase. The sensitivity and specificity of each index was analyzed in function of the MOAA/SS. We also analyzed the time elapsing from the moment the patient fell asleep (MOAA/SS 2) until the two indexes reached published reference values (ADI = 38, BIS = 60).

RESULTS

After induction with propofol (group A) the ADI fell to 29.2 +/- 11.7 and the BIS fell to 63.5 +/- 13.4. After induction with sevoflurane (group B) the ADI fell to 33.8 +/- 14.9 and the BIS to 66.8 +/- 15. The ADI value that best discriminated between arousal and sleeping (sensitivity 100%) was 38; the BIS value that best discriminated was 60. The responses to sound in decibels (dB) during "awake/sleeping" and "sleeping/awake" phases were, respectively, -3.8 dB and -4.5 dB for the ADI and -1.5 dB and -0.8 dB for the BIS. With the patient in stable sleep, response to the two indexes was at -0.79 dB. In group A, the ADI detected MOAA/SS 2 significantly earlier (ADI 13.1 +/- 30 s; BIS 56 +/- 36 s; p < 0.05). No patient reported remembering the study period.

CONCLUSIONS

Monitoring anesthetic depth with the ADI or BIS was technically easy and effective for detecting whether patients were awake or sleeping. The ADI response was faster and identified awake/sleeping and sleeping/awake phase changes better than did the BIS.

[Paraplegia after surgery for aneurysm of the descending thoracic aorta]

Postoperative paraplegia caused by ischemic injury of the spinal cord is the most disabling complication of thoracoabdominal surgery, particularly when repair of the descending thoracic aorta is involved. We describe the case of a 59-year-old man who underwent emergency surgery for placement of a Dacron prosthesis to repair a ruptured descending thoracic aorta aneurysm, using an aortic cross-clamping technique plus aortic-femoral partial bypass with normothermia and an ischemic time of 165 minutes. The early postoperative course included complete spinal syndrome with motor and sensory loss below T5, with consequent respiratory insufficiency of neuromuscular origin. The result was a difficult postoperative course including prolonged mechanical ventilation and recurrent respiratory infections. Possible causes include prolonged time of ischemia, inadequate monitoring of distal aortic pressure and inappropriate surgical technique related to the absence of angiographic data on spinal vascularization. We conclude that ischemic time should be kept to under 30 minutes whenever possible. In cases of prolonged ischemia, bypass techniques with outflow to the distal aortic segment are more effective whenever mean blood pressure at this point rises to 60 mmHg or more. Vasodilator use should be reserved for cases of severe arterial hypertension and left ventricular failure and/or life-threatening increases in aortic wall stress even if not leading to dangerous decreases in distal aortic pressure. Finally, angiographic study to obtain anatomical details of spinal blood flow is advisable.

Autosomal dominant nocturnal frontal lobe epilepsy in a Spanish family with a Ser252Phe mutation in the CHRNA4 gene

BACKGROUND

A large family with autosomal dominant nocturnal frontal lobe epilepsy from the south of Spain was studied. The clinical appearance of the disease in this family, which included 28 members, of whom 11 were affected and 2 were obligate carriers, was identical to that previously described in an Australian family and a Norwegian family, in which mutations in exon 5 of the CHRNA4 gene were found.

METHODS

Following DNA extraction, the family was genotyped with 4 fluorescent markers flanking the locus to the CHRNA4 gene on chromosome 20q13.3, and lod score computations were performed. The exon 5 of the CHRNA4 gene was amplified between nucleotides 535 and 825 and polymerase chain reaction products were purified and sequenced directly.

RESULTS

The same missense mutation as that found in the Australian family, C-->T, which causes the replacement of a serine with phenylalanine in amino acid 252 in exon 5, was detected. This mutation segregated with the disorder in all 11 affected members, in the 2 obligate carriers, and in 1 asymptomatic sibling, and was not found in 1 spouse and 1 daughter. Neither of the 2 polymorphisms found in a series of families with epilepsy were found in our sample [corrected].

CONCLUSIONS

These data confirm the clinical homogeneity in the phenotypic expression of autosomal dominant nocturnal frontal lobe epilepsy caused by mutation in the CHRNA4 gene, and the pathogenic role of the Ser252Phe mutation in this disorder.

Exposure to MDI during the process of insulating buildings with sprayed polyurethane foam

Buildings are often insulated with sprayed-in-place polyurethane foam in spite of the fact that few studies have been carried out on exposure levels to isocyanates during the spraying process. This paper is meant to provide new data on personal exposure to methylene-bis (4-phenylisocyanate) (MDI) while dwellings and office buildings are being insulated with polyurethane foam. An impinger using a 1-(2-methoxyphenyl)piperazine toluene solution as absorbent was used to take personal samples for the sprayer and helper during indoor and outdoor applications. The analytical results show that the levels of exposure were significant, especially for the sprayer, with values of up to 0.077 mg m-3 and 0.400 mg m-3 during outdoor and indoor applications, respectively. The helper's exposure was always lower.

Ministernotomy versus median sternotomy for aortic valve replacement: a prospective, randomized study

BACKGROUND

Minimally invasive aortic valve replacement reduces surgical trauma and, supposedly, postoperative pain, blood loss, and length of stay. A prospective, randomized study was designed to prove these theoretical advantages.

METHODS

Forty patients undergoing isolated, elective aortic valve replacement were randomized into two equal groups. Patients in group M underwent aortic valve replacement through a ministernotomy (reversed L or reversed C). In group S, a median sternotomy was used. The anesthetic and surgical protocol was identical for both groups. Pain was evaluated on a daily basis. Pulmonary function tests were performed preoperatively and before hospital discharge in all patients.

RESULTS

There were two deaths in each group. Cross-clamp time was longer in group M: 70 +/- 19 minutes versus 51 +/- 13 minutes in group S (p = 0.005). There were no statistically significant differences between groups M and S in pump time (95 +/- 20 minutes versus 83 +/- 19 minutes), extubation time (9.9 hours in both groups), chest drainage (479 +/- 274 mL/L 24 hours versus 355 +/- 159 mL/24 hours), transfusion requirements (27% in both groups), pain evaluation (1.34 +/- 1.3 versus 2.15 +/- 1.5), length of stay (6.2 +/- 2.3 days versus 6.3 +/- 2.5 days), and cosmetic appraisal. Forced vital capacity decreased 26% from preoperative reference values in group M and 33% in group S (p = not significant). Forced expiratory volume in 1 second decreased 22% and 35%, respectively (p = not significant).

CONCLUSIONS

This study has failed to prove the theoretical advantages of minimally invasive aortic valve replacement. With this technique, cross-clamp time is longer than with a median sternotomy.

[A case of malignant hyperthermia: anesthesia and recovery]

We report the case of a 29-years-old woman with Menière's syndrome undergoing surgery to drain the endolymphatic sack. After anesthetic induction trismus developed but tubes were inserted without difficulty. Tachycardia began 15 min after start of balanced anesthesia with isoflurane, as arterial oxygen saturation and CO2 pressure decreased and temperature increased. These symptoms responded favorably to immediate treatment with dantrolene sodium, which was continued for 30 h in the ward for postoperative intensive care. Blood chemistry reports showed high enzyme levels that peaked at 24 h. We stress the importance of monitoring end tidal CO2 pressure and of rapidly starting specific treatment with dantrolene for correction of the clinical picture described.

[Recessive distal myopathies. Five cases]

We present five patients with distal weakness in the lower extremities with onset in adolescence. Paresis tended to occur in the gastrocnemia in 3 patients and was accompanied by marked elevation of CPK (> 10 times higher than normal). Muscle biopsies showed signs of dystrophy. The clinical picture for these patients was consistent with the diagnosis of recessive distal myopathy (Miyoshi's form). The differential sign in the other 2 cases was greater involvement of the anteroexternal leg muscles and the presence of rimmed vacuoles similar to those characteristic of Nonaka's vacuolar distal myopathy.

[Evaluation of tissue perfusion by simultaneous non-invasive monitoring of the hemodynamic profile and capnography]

OBJECTIVES

To assess the simultaneous variations in blood gases and CO2 tele-expiratory pressure (ETCO2) produced by changes in tissue perfusion in anesthetized patients with stable lung perfusion, alveolar ventilation and metabolic states.

MATERIAL AND METHODS

Forty patients were divided into two groups. Group 1 included 20 ASA I patients undergoing orthopedic surgery on the lower extremities. Group 2 included 20 ASA I-III patients undergoing peripheral vascular surgery during which myocardial depression developed after isoflurane administration. The decrease in minute volume was measured in the descending aorta by esophageal ultrasound in both groups. Other hemodynamic parameters were measured by digital plethysmography. ETCO2 was measured by lateral aspiration capnography, and central venous pressure was measured in group 2 by subclavian venous catheter. Measurements were taken before and after release of the tourniquet in group 1, and before and after the decrease in minute volume (> 30%) in group 2.

RESULTS

Release of the tourniquet after a mean compression time of 51 +/- 07 minutes produced an increase of 52% (p < 0.001) in minute volume in all patients in group 1; an increase of 23% (p < 0.001) in ETCO2; and a decrease of 60% (p < 0.001) in total vascular resistance. In group 2 a 15% decrease in ETCO2 (p < 0.01) was observed, coinciding with a 35% decrease in minute volume (p < 0.01).

CONCLUSIONS

An increase in minute volume produces an increase in ETCO2 while a decrease in minute volume results in a decrease in ETCO2. This means that sharp changes in ETCO2 may be useful in judging the degree of change in tissue perfusion when other parameters like alveolar ventilation, lung perfusion and metabolic rate remain constant.

[Thoracic paravertebral blockade: postoperative analgesic effectiveness and plasma concentrations of bupivacaine]

AIMS

To compare the analgesic efficacy of thoracic paravertebral blockade with that of endovenous morphine to measure the plasma levels of bupivacaine and to study the complications derived from both techniques in patients undergoing thoracic or abdominal surgery with unilateral incision.

METHODS

Twenty ASA I-II patients allocated to two groups (A and B) of ten patients each were studied. Group A (5 cholecystectomies and 5 thoracotomies) received morphine 0.075 mg/kg i.v. every 3 hours after operation. Group B (5 cholecystectomies and 5 thoracotomies) received thoracic paravertebral blockade 15 ml of 0.37-5% bupivacaine with 1:200.000 adrenaline following tracheal extubation. Analgesia was evaluated according to the visual analogic scale (VAS) with laterality and extension of the blockade being assessed. The plasma levels of bupivacaine were measured by liquid chromatography in 5 patients. Blood pressure, heart rate and respiratory frequency were assessed in both groups. In group B the appearance of pneumothorax or other local complications were noted. The results were statistically analyzed using to the Student's test.

RESULTS

The patients in group A presented significantly more pain than those of group B. In these patients analgesia was unilateral. Plasma levels ranged between 0.56 mg/l at 5 minutes of administration and 0.17 mg/l at 240 minutes with a peak of 0.70 mg/l at 10 minutes with all these values being considerably lower those a determined as toxic (2-4 mg/l). No significant differences were found between the values of blood pressure, and cardiac and respiratory frequency of both groups. There were no complications derived from the technique.

CONCLUSIONS

Thoracic paravertebral blockade is a very effective postoperative analgesic technique and is superior to that of i.v. morphine in patients undergoing thoracic or unilateral abdominal surgery. Peak plasma levels were much lower than those considered as toxic complications of interest were observed. Therefore, this technique may be considered as an alternative to other blockades such as extradural, interpleural or intercostal.

[Multi-infarct dementia in giant cell arteritis (temporal arteritis)]

Dementia is an infrequent and little known manifestation of giant cell arteritis or temporal arteritis (GCA-TA). The cases of 2 women with histologically proven GCA-TA are presented in which, together with the most classical symptoms, they presented a brusque mental deterioration on initiation of the disease. One patient developed a severe irreversible dementia which coincided with a rapid reduction in the doses of corticoids; while the other patient demonstrated improvement in cognitive function with steroid treatment and control of the disease. Magnetic resonance studies revealed multiple areas of infarction in both hemispheres in the two patients. The importance of treating multi-infarct dementia is underlined in the context of GCA-TA with high doses of corticoids. It is also emphasized that GCA-TA should be considered in the evaluation of older patients with mental alterations.