Cochlear dysfunction as an early biomarker of cognitive decline in normal hearing and mild hearing loss

INTRODUCTION

Age-related hearing loss is an important risk factor for cognitive decline. However, audiogram thresholds are not good estimators of dementia risk in subjects with normal hearing or mild hearing loss. Here we propose to use distortion product otoacoustic emissions (DPOAEs) as an objective and sensitive tool to estimate the risk of cognitive decline in older adults with normal hearing or mild hearing loss.

METHODS

We assessed neuropsychological, brain magnetic resonance imaging, and auditory analyses on 94 subjects > 64 years of age.

RESULTS

We found that cochlear dysfunction, measured by DPOAEs-and not by conventional audiometry-was associated with Clinical Dementia Rating Sum of Boxes (CDR-SoB) classification and brain atrophy in the group with mild hearing loss (25 to 40 dB) and normal hearing (<25 dB).

DISCUSSION

Our findings suggest that DPOAEs may be a non-invasive tool for detecting neurodegeneration and cognitive decline in the older adults, potentially allowing for early intervention.

Atypical pattern of response in rectal cancer after neoadjuvant pembrolizumab treatment: a case report, literature review, and proposed management model

Background

Immunotherapy is the first-line treatment in patients with advanced microsatellite instability-high (MSI-H) or deficient mismatch repair (dMMR) colorectal cancer (CRC). Although immune checkpoint inhibitors (ICIs) for locally advanced rectal cancer (LARC) are not yet a standard, the results are very encouraging and raise the question of whether patients with clinical complete response (cCR) could receive nonoperative management (NOM). However, different patterns of response have challenged management strategies.

Case Description

A 34-year-old woman diagnosed with dMMR LARC started treatment with capecitabine 2,000 mg/m² on day 1 to 14 and oxaliplatin 130 mg/m² on day 1 and every 21 days. Magnetic resonance imaging (MRI), performed three cycles later, showed local progression of the primary rectal lesion, which at that time had new peritoneal reflex involvement. A new hepatic lesion in segment V was observed. Due to disease progression, she was administered pembrolizumab 200 mg every 21 days. After three cycles, a discordant radiological response was observed on a new MRI scan that showed a complete response of the liver lesion and magnetic resonance tumor regression grade (mrTRG) 1 in the rectum. However, new involvement of the mesentery and enlargement of the regional lymph nodes (LNs) were also evident. A new colonoscopic biopsy was performed, showing no cancerous cells. She underwent surgery on the rectum and liver lesion. Pathology showed a complete response of the rectal wall and liver lesion, but 1 of 22 LNs was positive for adenocarcinoma (ypT0 N1 M0). The patient continued on pembrolizumab, and 14 months after surgery, she had not relapsed.

Conclusions

Neoadjuvant immunotherapy for rectal cancer requires new recommendations for the assessment of clinical response. Pseudoprogression should be ruled out as an atypical response before deciding on surgical treatment. We propose an algorithm to address pseudoprogression in this setting.

[Pembrolizumab-induced gastritis with PDL1 histological expression]

Immune-mediated gastritis is a rare adverse effect in patients treated with immune checkpoint inhibitors. We present a patient with a diagnosis of cervical carcinoma under treatment with pembrolizumab who was admitted with nausea, vomiting and weight loss; an endoscopy revealed a ulcerated lesion covered by mucus in the antrum and gastric body. The biopsy revealed extensive denudation of the gastric mucosa with fibrin leukocyte reaction. Into the lamina propria, an increased lymphocytic and polymorphonuclear inflammatory infiltrate was observed. Immunohistochemistry confirmed positivity for PDL1 (clone SP2630) and combined positive score of 35%, with a relative contribution of epithelial cells of 25% and inflammatory cells of 10%. After three weeks with 30 mg meprednisone, a new endoscopy revealed a stomach with clear mucus content; fundus and body without lesions, and an antrum with congestive mucosa and multiple superficial ulcers covered by fibrin. Diagnostic and therapeutic aspects of immune-mediated gastritis are described.

Methylation Status of GLP2R, LEP and IRS2 in Small for Gestational Age Children with and without Catch-up Growth

OBJECTIVE

In small for gestational age (SGA) children, catch-up growth could be influenced by methylation of several genes involved in metabolism. Epigenetics may influence the development of metabolic diseases in adulthood. To compare the methylation of leptin (LEP), glucagon-like peptide-2 receptor (GLP2R), insulin receptor substrate-2 (IRS2) in SGA patients with and without catch-up growth.

METHODS

Observational prospective study of SGA children. Demographical and clinical variables were collected from clinical records and parents’ questionnaire. Methylation status of LEP, IRS2, and GLP2R promoters was evaluated in DNA extracted from patient and one parent saliva samples.

RESULTS

Forty-eight SGA patients were included. Twenty-six (54.2%) had catch-up growth phenotype and 22 (45.8%) did not. The median age was 5.2 years [RIC 4.1-6.8] without difference between groups (p=0.306). The catch-up group had increased appetite (42.3% vs 9.1%, p=0.008), family history of dyslipidemia (42.3% vs 27.3%) and diabetes (34.6% vs 22.7%) compared to non-catch-up group. Catch-up patients had significantly larger waist circumference compared to non-catch-up group (median 55 cm [RIC 52-58] versus median 49.5 cm [RIC46-52]; p<0.001). LEP and GLP2R were methylated in all samples. IRS2 was methylated in 60% of SGA patients without difference between groups (p=0.520).

CONCLUSION

There is no association between IRS2 methylation and catch-up growth among SGA patients. LEP and GLP2R were methylated in all SGA patients. Gene methylation may be implicated in metabolic disease later in life. More studies should be performed to confirm this hypothesis.

IRC data for a mechanistic route starting with H2O adsorption and finishing with H2 desorption from graphene

Intrinsic reaction coordinate (IRC) data regarding the interactions of water with a carbene-like active site located at the edge of a polyaromatic hydrocarbon [1-3] has been obtained using density functional theory (DFT) and the 6-31g(d) basis set as implemented in the Gaussian 16 software [4]. The data is presented as two videos (frontal and lateral mechanism views) combining four consecutive IRC calculations corresponding to the four different transition states presented on "https://doi.org/10.1016/j.carbon.2020.01.011" [3] (Figure 6, side approach). These videos provide powerful insights on two key aspects: a) the rotational process that occurs during water adsorption and b) the hydrogen gas desorption process during water gasification of carbons.

Pediatric Palliative Care During End of Life: A Privilege of a Few in a Tertiary Referral Hospital From Colombia

BACKGROUND

We aim to describe the access to palliative care (PC) in hospitalized children during end-of-life care and compare the circumstances surrounding the deaths of hospitalized children as a basis for implementing a pediatric PC program at our institution.

METHODS

We performed a retrospective chart review of deceased pediatric patients at a tertiary referral hospital in Colombia. The study group was selected by randomly drawing a sample of 100 observations from the 737 deceased children from 2013 to 2016. A 1:1 propensity score (PS) matching was performed to compare the characteristics and outcomes between PC and non-PC treated patients.

RESULTS

We included 87 patients. After PS matching, we found that patients under the care of non-PC physicians were more likely to die in the pediatric intensive care unit (non-PC: 6/10 vs PC: 1/10; P = .02), to be on vasopressor agents and mechanical ventilation (non-PC: 7/10 vs PC: 1/10; P = .02), and to receive cardiopulmonary resuscitation at the end of life (non-PC: 5/10 vs PC: 0/10; P = .03). In contrast, a significantly higher proportion of patients under the care of the pediatric PC team died with comfort measures (non-PC: 2/10 vs 8/10; P = .02) and nonescalation of care in physician orders (non-PC: 5/10 vs PC: 10/10; 0.03).

CONCLUSION

In this study, only 10 of 87 patients were treated by the pediatric PC team at the end of life. The latter finding is concerning and is a call to action to improve access to pediatric PC at our institution.

The reduction of Fe-bearing copper slag for its use as a catalyst in carbon oxide hydrogenation to methane. A contribution to sustainable catalysis

Reduction of Fe-phases in a slag from the copper smelting process is studied for its use as a catalyst in methanation of carbon oxide (CO). This material contains 36.4 wt% Fe and the main Fe-phases in its fresh and reduced forms were identified and quantified. Chemical analysis and X-ray diffraction (XRD) for crystalline phase detection and determination of Fe dispersion were carried out. Reducibility of Fe-oxides was studied by thermal programmed reduction (TPR) under H₂ at 650 and 800 °C using 0.5 and 2 h soak time. In the fresh slag, iron was found to be in the form of Fe₃O₄ (17.4 wt%) and fayalite, Fe₂SiO₄ (43.4 wt%). The composition was experimentally determined and verified by stoichiometric balances and thermogravimetric analysis (TGA). Upon reduction at 800 °C and 2 h soak time, 87 % of the Fe-phases were reduced, leaving an activated catalyst with a 35.2 % Fe⁰, which is the active phase for CO hydrogenation to methane. An expression was derived to determine the Fe⁰ concentration in the reduced slag based on the composition of the fresh slag and its reduction degree. The catalytic activity of the reduced slag during CO hydrogenation was evaluated in a fixed bed differential reactor. The selectivity to methane, at 300 °C, was 87 %, thus confirming its catalytic activity for the selected reaction.

C-doped anatase TiO2: Adsorption kinetics and photocatalytic degradation of methylene blue and phenol, and correlations with DFT estimations

This work shows an easy and eco-friendly methodology to obtain almost pristine anatase phase of TiO₂ by using furfural, a biomass-derived molecule, as a bio-template. The photocatalytic activity was studied following the degradation of methylene blue and phenol under artificial solar irradiation. Results were compared against those obtained on a commercial pristine anatase TiO₂. The pseudo first-order, the second-order and the intraparticle diffusion kinetic models were verified. The textural and surface chemistry properties of the materials were correlated with the surface density of molecules adsorbed in equilibrium. The reaction-rate showed an almost perfect quadratic regression as a function of the surface density. Theoretical estimations of the density of states by DFT + U were performed showing that the total electron charge in the oxygen bonded to anatase TiO₂ increased due to carbon doping in agreement with the prediction of appearance of atomic orbitals 2p from carbon atom in the hybrid material. C-doping is responsible of the red-shift from 3.14 to 2.94 eV observed for a Ti₁₅O₃₂C super-cell than pristine anatase Ti₁₆O_32. The increase in the activity of the C-doped TiO₂ photocatalyst was due to the decrease in the energy band-gap promoting a higher absorption of photons from the visible light.

[Pulmonary co-infection due to Nocardia cyriacigeorgica and Aspergillus fumigatus]

OBJECTIVE

Pulmonary nocardiosis is an uncommon pulmonary infection caused by aerobic gram-positive bacteria of the genus Nocardia. Nocardia sp. are environmental organisms spread worldwide. Approximately 50 Nocardia species have been described to date, about 30 of which are known to cause human disease. Nocardia cyriacigeorgica was first reported in 2001.

CASE REPORT

We report a case of infection caused by N. cyriacigeorgica in a patient with B-cells non-Hodgkin lymphoma and diabetes mellitus. The microbiological findings reflect a possible co-infection by N. cyriacigeorgica and Aspergillus fumigatus.

CONCLUSIONS

Patient's background and information related to risk factors are essential to detect the growth of Nocardia sp. in the laboratory. Furthermore, diagnosis of invasive pulmonary aspergillosis is particularly controversial, especially in intensive care units patients. Taking everything into account, we will discuss a possible co-infection by N. cyriacigeorgica and A. fumigatus in a critically ill patient.

Pediatric trauma at a general hospital in Cali, Colombia

BACKGROUND

Trauma is an important cause of morbidity and mortality in children. Blunt trauma is the most common type and falls and road traffic injuries (RTI) are the most frequent mechanisms.

METHODS

Secondary analysis of institutional data included within the Panamerican Society of Trauma Registry (STP-ITSDP). A total of 581 trauma patients younger than 18years, hospitalized between 2012 and 2014, were included.

RESULTS

Blunt trauma (BT) (68%) was the most common type, and falls (42.5%) the most common mechanism. Median age was: 14years for penetrating trauma (PT), 8years for BT, and 5.5years for other types of trauma (OT). Of all patients, 8.1% had a Glasgow score<8, 9% had a Glasgow score of 8-13 and 81.1% had a Glasgow score higher than 14. Death occurred in 5.2% of patients: 83.3% as inpatients and 16.7% during initial management in the emergency room (ER). Patients dying in the ER were mostly PT victims, with higher ISS and lower Glasgow scores.

CONCLUSIONS

Trauma is an important cause of morbidity and mortality in our pediatric population. Fundación Valle de Lili (FVL), a referral hospital, receives a high number of trauma patients from southwestern Colombia. Detailed knowledge of epidemiological data will help us to develop rapid response strategies for patients with trauma and to develop prevention and promotion programs.

Experience with Guillain-Barré syndrome in a neurological Intensive Care Unit

INTRODUCTION

Guillain-Barré syndrome, an acute polyradiculoneuropathy that presents with weakness and areflexia, is the most common cause of acute flaccid paralysis. In certain patients, respiratory failure is secondary to this disorder, eventually causing patients to require mechanical ventilation and experience additional complications due to diminished respiratory support and related mobility limitations. Prognoses for most of these cases are positive; treatment consists of basic support combined with plasmapheresis or administration of immunoglobulins.

OBJECTIVE

This study sought to describe the socio-demographic, clinical, laboratory and neurophysiological characteristics of patients with Guillain-Barré syndrome who were hospitalised in the Intensive Care Unit of the Neurological Institute of Colombia between 2006 and 2012.

METHODOLOGY

This study presents a case series.

RESULTS

We surveyed 25 patients (32% female and 68% male) with Guillain-Barré syndrome and an average age of 54 years. Sixty per cent of these patients were admitted between days 3 and 7 after symptom onset; 64% had a history of respiratory infection and 20% had a history of intestinal infection. In addition, 84% of the patients presented with albuminocytological dissociation. We observed the following clinical subtypes of Guillain-Barré syndrome: inflammatory demyelinating polyneuropathy in 32%, acute motor-sensory axonal neuropathy in 28%, acute motor axonal neuropathy in 28%, and Miller Fisher syndrome in 12%.

CONCLUSIONS

In this descriptive study of a group of critical care patients with GBS, results depended on patients' clinical severity at time of admission. Our findings are similar to results published in the international literature.

Emerging Trichosporon asahii in elderly patients: epidemiological and molecular analysis by the DiversiLab system

Trichosporon asahii has been recognized as an emerging opportunistic agent for invasive infections, mainly in immunocompromised patients. Urinary tract infections by this pathogen may also occur, especially in patients with urinary obstruction or those undergoing vesical catheterization and antibiotic treatment. Many outbreaks of Trichosporon spp. have been detected after urinary catheter manipulations. We report the molecular-epidemiological characterization of T. asahii in our institution using the DiversiLab system for the molecular strain typing and compare three different methods for susceptibility testing. Our results present T. asahii as an emergent pathogen in elderly patients with urinary drainage devices that can be adequately treated with triazoles, with voriconazole being the most active. Broth dilution and Vitek 2 had good concordance, while Etest showed more discrepancies. In addition, the DiversiLab system for clonal strain typing may be a useful tool for fast and accurate management of nosocomial outbreaks.

[Hemodynamic monitoring in the critically patient. Recomendations of the Cardiological Intensive Care and CPR Working Group of the Spanish Society of Intensive Care and Coronary Units]

Hemodynamic monitoring offers valuable information on cardiovascular performance in the critically ill, and has become a fundamental tool in the diagnostic approach and in the therapy guidance of those patients presenting with tissue hypoperfusion. From introduction of the pulmonary artery catheter to the latest less invasive technologies, hemodynamic monitoring has been surrounded by many questions regarding its usefulness and its ultimate impact on patient prognosis. The Cardiological Intensive Care and CPR Working Group (GTCIC-RCP) of the Spanish Society of Intensive Care and Coronary Units (SEMICYUC) has recently impulsed the development of an updating series in hemodynamic monitoring. Now, a final series of recommendations are presented in order to analyze essential issues in hemodynamics, with the purpose of becoming a useful tool for residents and critical care practitioners involved in the daily management of critically ill patients.

Differential time to positivity of blood cultures: a valid method for diagnosing catheter-related bloodstream infections in the intensive care unit

PURPOSE

The validation in critical patients with short-term catheters of a method for diagnosing catheter-related bloodstream infection (CR-BSI), based on the differential time to positivity (DTP) of blood cultures.

METHODS

Patients suspected of having CR-BSI were included. Two peripheral vein blood cultures and a catheter hub blood culture were simultaneously carried out. The responsible catheter was removed and tip cultured. Times to positivity of all blood cultures were automatically registered. CR-BSI was diagnosed when all the cultures were positive for the same microorganism and DTP≥120 min. This diagnosis was compared with the one obtained using the standard method.

RESULTS

226 cases suspected of CR-BSI were analyzed during a 20-month period. A total of 19 removed catheters were associated with CR-BSI. Seven cases of polymicrobial cultures (4 with CR-BSI) were discarded from the final analysis due to the impossibility of determining the time to positivity for each individual microorganism. Using the DTP method, 12 out of 15 CR-BSI cases were diagnosed (sensitivity 80%, specificity 99%, PPV 92%, NPV 98%). In a ROC curve, we found a cut-off value of 17.7 h in positivity of hub blood cultures that may be useful for diagnosing CR-BSI.

CONCLUSION

DTP can be a valid method for CR-BSI diagnosis in critically ill patients, avoiding unnecessary catheter withdrawal.

Mechanism of the schultz-dale reaction in the denervated diaphragmatic muscle of the Guinea pig

The mechanism of the contractions elicited by specific antigens in immunologically sensitized muscle tissue (Schultz-Dale responses) has been investigated on single fibers of denervated guinea pig hemidiaphragms. This preparation can be either actively or passively allergized, showing Schultz-Dale responses similar to those of visceral muscle. Specific antigens were applied with an electrically operated microtap to discrete areas of the cell surface while recording the electrical activity with intracellular microelectrodes. In this manner, a depolarizing action of the antigens on the muscle membrane was demonstrated. Brief applications of antigen gave rise to phasic potential changes (antigen potentials) similar to those elicited in the same fibers with acetylcholine-filled microtaps. However, antigen potentials occur only in denervated fibers sensitized to the specific antigen or closely related proteins; they are not seen in either innervated fibers of allergized animals or in denervated, nonallergized fibers. Repeated antigen application to the same area of the fiber causes a local irreversible desensitization. The antigen potentials are associated with a reduction in the resistance of the muscle membrane, similar to that caused by acetylcholine. It is concluded that besides causing the liberation of biogenic amines from the mast cells, antigens exert a direct action on the permeability of the muscle membrane; the molecules of antibody adsorbed to the cells appear to act as specific chemoreceptors for the antigen.

[Diagnosis and management of colon perforation after colonoscopy]

BACKGROUND

Colon perforation is an uncommon but feared complication of colonoscopy. The treatment is usually surgical but occasionally it does not require an operation.

AIM

To report our experience in the diagnosis and management of colon perforation after colonoscopy.

MATERIAL AND METHODS

Retrospective review of the database of 11,720 colonoscopies. The medical records of those patients that had a perforation were reviewed.

RESULTS

Twelve perforations in patients aged 26 to 92 years (six women), were identified with a global perforation rate of 0.1%. Five occurred during diagnostic and seven during therapeutic procedures. All perforations were confirmed by a plain X ray or CT scan of the abdomen. Four patients, without signs of initial diffuse peritoneal irritation, were medically treated. One of these, finally required surgery. Among operated patients, a primary suture was done in five, a primary excision without colostomy in three and a Hartmann procedure due to a severe peritoneal contamination in one. No patient died.

CONCLUSIONS

There is a higher risk of colon perforation during therapeutic colonoscopies. Selected cases may be safely treated without surgery.

Lead acetate action on anaphylactic response of guinea pig smooth muscle

Experiments were performed to evaluate lead acetate effects on the anaphylactic contraction in guinea pigs smooth muscles. Aortic rings from guinea pigs exposed to lead acetate developed an anaphylactic contraction significantly lower than the contraction induced by the antigen in controls. In the smooth muscle of the intestine, lead acetate did not modify the anaphylactic response. Lead induced immunosuppression of the anaphylactic response of aortic rings, whereas sodium acetate had no effect on the anaphylactic reaction of the guinea pig smooth muscle. The amplitude of the norepinephrine contraction was not modified by lead nor by sodium acetate.

Effect of stress on the Schultz-Dale reaction in guinea pig aorta

The smooth muscle of thoracic aorta from guinea pig sensitized with egg albumin (EA) produced an anaphylactic contraction when it was exposed to EA. Experiments were performed to evaluate stress effects on the anaphylactic contraction in guinea pig aortic rings. Two types of stressors were used as immunosuppressor stimuli: physical restraint and shaking of the animals. Both stressors diminished the amplitude of the Schultz-Dale contraction in aortic rings from sensitized guinea pig. The shake stress stimulus interrupted several times during each session induced higher immunosuppression in animals in which the active sensitization and the stress sessions began the same day. Severe restraint stress, prior to active immunization, also suppressed significantly the anaphylactic response. The Schulz-Dale reaction in guinea pig aorta seems to be a valuable technique to study the stress effects on the anaphylactic response.

Novel carbocyclic nucleosides containing a cyclobutyl ring. Guanosine and adenosine analogues

(1R,cis)-2-(3-Amino-2,2-dimethylcyclobutyl)ethanol (4) was used as a precursor in the synthesis of cyclobutyl nucleoside analogues containing guanine, 8-azaguanine, adenine or 8-azaadenine. All the compounds were evaluated as antiviral agents in a variety of assay systems. Some activity was noted for compound 13, 17, 19 and 20 against vaccinia virus and for compounds 11, 12, 13, 17, 19 and 20 against herpes simplex virus, at concentrations that were up to 10-fold below the cytotoxic concentrations for the host cells.

Vasoconstrictor effect of Cissus sicyoides on guinea-pig aortic rings

1. The effect of the aqueous extract of Cissus sicyoides (CS) on isolated guinea pig aortic rings was studied. CS contracts the smooth muscle of the aorta in a dose-response relation. 2. The extract of CS increases the norepinephrine contraction in normal calcium and in solutions without calcium. 3. Lanthanum inhibits the contraction induced by CS. 4. The vasoconstrictor effect of CS was increased in solutions without calcium or with low calcium, which is an inverse calcium-dependent contraction. 5. Prolonged exposure to calcium-free solution did not abolish CS contraction. These contractions can be elicited repeatedly even after 6 hr of continuous exposure to calcium-free solutions. 6. Caffeine reduces contractile response induced by CS in normal calcium, as well as in solutions without calcium. 7. Our results support the idea that the aqueous extract of CS acts at the membrane level, increasing the calcium entry through the membrane as well as acting on the internal calcium deposits, possibly on the sarcoplasmic reticulum.

[Experimental free muscle transplantation. Is autologous graft on the distal esophagus viable?]

Experimental free muscle transplantation has resulted in some successful clinical applications.

AIM

The possibility that this type of transplantation could act as a sphincteric mechanism motivated us to start by assessing the viability of autologous skeletal grafts on the distal esophagus of laboratory animals.

MATERIAL AND METHODS

Twenty transplants of previously denervated free plantaris muscle grafted on the distal esophagus of Sprague-Dawley rats were evaluated at the 1st, 2nd, 4th, 8th and 16th posttransplant week. Histological and histochemical studies were performed to evaluate general features of the grafts and the muscle fibers condition.

RESULTS

One and two weeks after transplant the grafts show large areas of necrosis with inflammatory infiltrate. Between the 2nd and the 4th week, as revascularization and motor endplates become significant, the areas of necrosis begin to regress and they almost disappear by the 8th week. Since the 4th week after transplant, regenerated muscle fibers demonstrate morphological and biochemical features similar to normal.

CONCLUSIONS

Experimental free plantaris muscle transplantation on the distal esophagus is viable and shows revascularized and reinnervated muscle fibers from the 8th week after transplant on, and at least until the 16th. These fibers have the structural and metabolic properties enabling contractile function. This original model may allow further investigation of some features related to pathophysiology and therapy of gastroesophageal reflux.

[Specificity of CK-MB enzyme in the diagnosis of acute myocardial infarction in the postoperative period following non-cardiac surgery]

OBJECTIVES

1) To determine plasma concentrations of creatinphosphokinase-MB (CK-MB) enzyme during non-cardiac surgery for detecting postoperative myocardial infarction or ischemia. 2) To assess the specificity of CK-MB levels for the diagnosis of acute myocardial infarction (AMI) in patients undergoing non-cardiac surgery.

PATIENTS AND METHOD

Three hundred twenty-eight patients were studied prospectively. Inclusion criteria were as follows: 1) presenting cardiac risk factors; 2) major surgery; and 3) presence of associated pathology, unrelated to cardiac pathology. All patients were given an electrocardiogram and CK-MB levels were determined every 8 hours over the first 24 hours and on the second and third days. Total CK was measured at 24 hours.

RESULTS

AMI was detected by electrocardiogram in 3.3% of the patients. ST-segment/T-wave changes were detected in 5.7% and myocardial ischemia was found in 14.7%. Mean levels of CK-MB in patients with postoperative AMI were significantly higher than in patients without AMI. Total CK levels in patients with electrocardiographic changes were not significantly different from those of other patients. Thoracic surgery produced a significant increase in total CK but no increase in CK-MB. Patients undergoing esophageal surgery presented high initial levels of CK-MB that became normal.

CONCLUSIONS

1) The CK-MB/total CK ratio is highly specific for detection AMI after surgery. 2) Type of surgery affects total CK levels. 3) Detection of high levels of MB fraction should lead to a suspicion of myocardial damage. 4) Total CK level is not a good marker of myocardial necrosis in the postoperative period.

[Experimental alkaline reflux esophagitis. Role of the refluxed material]

Alkaline reflux is new recognised to play an important place in gastroesophageal reflux disease. In order to investigate the role of refluxate in the development of esophagitis we have performed an experimental study in laboratory animals submitted to alkaline reflux inducing operations. We produced esophagitis in two experimental groups of Sprague-Dawley rats: group I, end-to-side esophagojejunostomy (EY) and group II, esophagojejunostomy with partial derivation of afferent loop by an omega-like conduit (EO) designed to attain lesser reflux. Group III consisted of sham laparotomized animals (L). RESULTS. At day 14, all the animals of experimental groups have developed esophagitis, but the macroscopic extent and histological grade in group EO (med: 27 mm; grade 2) were significantly lower than in group EY (med: 35 mm; grade 3). Biochemical measurements (med) in esophageal washout revealed: a) pH were alkaline in all groups with a decrease in experimental groups that was only significant in group EY; b) Amylase, lipase and bile acids in groups EY (8090; 498; 32) and EO (12840; 449; 50) were similar, but significantly more higher than in group L (920; 24; 0). The analysis of correlation between esophagitis parameters and biochemical measurements revealed no significant ones except for pH (r = -.437 and -.417). CONCLUSIONS. 1- The alternative model (EO) presents lesser grade and extent of esophagitis. 2) The refluxate was rich in bile acids and pancreatic enzymes what is proof of the actual occurrence of reflux and supports its determinant contribute to the development of esophagitis. 3) Esophagitis has developed at alkaline pH but with no alkalinity increase in the experimental groups what indicate that "alkaline reflux esophagitis" is not an appropriate denomination. 4) The discrepancy between the biochemical analysis in esophageal washout and the extent and grade of esophagitis suggests that others than the nature and amount of refluxate (e.g. mucosal resistance) could play a role in reflux esophagitis.

[Peroperative myocardial infarction and myocardial ischemia in non cardiac surgery: prevalence and predictive factors]

BACKGROUND

The decrease in the prevalence of infarction in the population has not been accompanied by a reduction in postinfarct mortality, particularly in the population segment which does not present major symptoms of coronary disease. The aim of the present study was to determine the incidence and predictive factors of cardiac complications in patients undergoing non cardiac surgery.

METHODS

Eight hundred seventy-five patients undergoing elective surgery from May 1990-1991 had some of the following criteria: history of heart disease, major surgery, and medical risk other than cardiac. A sample of 328 patients was selected to whom an ECG an CK-MB isoenzyme test were performed on admission, every 8 h, and at the second and third days. Infarction or ischemia were diagnosed by electrocardiographic and enzymatic criteria. Minimum follow up was 72 hours.

RESULTS

IAM was diagnosed in 10 cases (3%, confidence interval 95%, 2 to 4%) and ischemia in 47 cases (14%, CI 95%, 11 to 18%). Operative mortality of cardiac origin was 4% (CI 95%, 2 to 6%). Arrhythmia not preoperatively present was detected in 11%, hemodynamic instability in 25%, and sinusal tachycardia in 21%. Other complications were: abdominal 12%, respiratory 14%, neurologic 6% and renal 4%. The appearance of cardiac complications was related with: ASA classification (p < 0.05), previous history of heart disease (p < 0.01), cardiovascular drug administration (p < 0.01) and changes in preoperative electrocardiogram (p < 0.001).

CONCLUSIONS

The present study suggests that patients with changes of the ST-T segment in the preoperative ECG should undergo examination to determine the degree of cardiac involvement. A strict peroperative hemodynamic control may reduce the prevalence of cardiac complications in those patients at high risk.

[Surgical management of congenital tracheal stenosis]

A six month old infant with dextrocardia, butterfly vertebrae and oesophageal atresia type I is reported. After surgical repair, she developed respiratory distress, needing ventilatory support. The bronchoscopy and bronchography demonstrated segmental tracheal stenosis. A resection of the stenotic segment was performed, and tracheal reconstruction with terminoterminal anastomosis. After a period of clinical improvement, respiratory distress came back and reestenosis was ascertained locating its level on the anastomosis. Three sessions of balloon dilation were ineffective and because that it's decided the introduction of a metallic self-expandable stent. After a transient relief, the patient had a bilateral pneumonia ending with the dead of the patient. In spite of the treatment used, it was not possible to accomplish solution in a middle or a large place. This constitutes a clear exponent of the complexity in the management of the congenital tracheal stenosis.

[Reflux esophagitis in an experimental model. Are the systemic consequences attributable to the esophagitis?]

The esophagojejunostomy model of reflux esophagitis has been shown to cause nutritional deterioration and alterations of hematologic parameters. However, these disturbances have been assumed rather than proved to be the consequence of esophagitis. Little attention has been paid to the anatomical and physiological alterations related to the reflux-inducing operation. We produced reflux esophagitis by an end-to-side esophagojejunostomy (EJ) in Sprague-Dawley rats. These rats were compared to a second group with a similar operation not leading to reflux esophagitis (Roux-en-Y esophagojejunostomy, R-Y). Sham operated animals were used as controls. Erosive esophagitis was produced in all but one of the EJ subjects at day 14, and in none of the R-Y animals. Significant weight loss (-21.7%), anemia (HCT, -17.3%) and hypoproteinemia (-14.2%) were seen in EJ model with respect to sham group. However, a similar variation of weight (-28.7%) and hematocrit (-26.2%) were also found in Y-R group; therefore, these parameters seemed to correlate more with the surgical challenge itself than with the esophagitis.