Guillain-Barré syndrome associated with SARS-CoV-2 infection: A case series from 4 Colombian cities during the pandemic.

SARS-CoV-2 infection has been associated with multiple neurological manifestations. One such manifestation, which has been described since the early stages of the COVID-19 pandemic and is relevant for current neurological practice, is Guillain-Barré syndrome (GBS). The literature describes neurotoxic mechanisms of the virus itself and the possible pathways by which it may affect the peripheral nerves in experimental studies; however, we still lack information on the mechanisms causing the immune response that gives rise to GBS in the context of SARS-CoV-2 infection. Colombia is one of the Latin American countries worst affected by the pandemic, with the third-highest number of cases in the region; thus, it is essential to recognise GBS, as this potential postinfectious complication may severely compromise the patient's functional status in the absence of timely diagnosis and treatment. We present a series of 12 cases of GBS associated with SARS-CoV-2 infection from hospitals in 4 different Colombian cities and describe the clinical presentation, laboratory and electrophysiological study findings, and treatment.

En el año 2020 se declaro la pandemia ocasionada por la infección por el virus SARSCoV-2, virus de la familia del coronavirus, adoptándose el nombre de COVID-19 a la enfermedad 1. En Bogotá, Colombia, se confirmó el primer caso de COVID-19 el 6 de marzo de 2020 (2). Los principales síntomas reportados en la infección por SARSCoV-2 son fiebre (43.8% en la admisión y 88.7% durante la hospitalización) y tos (67.8%) (3). Otros síntomas encontrados son fatiga (38.1%), producción de esputo (33.7%) y cefalea (13.6%). Los principales signos neurológicos reportados en los pacientes con infección severa por SARS-Cov-2 son agitación (69%), compromiso en tracto corticoespinal (67%) y delirium (65%) (4). Las principales complicaciones neurológicas descritas asociadas a Covid 19 son: anosmia, disgeusia, encefalopatia, Síndrome de Guillain Barre, complicaciones cerebrovasculares y daño en musculo esquelético (5­8).En el presente articulo se presenta una serie de casos de pacientes con síndrome de Guillain-Barré asociado a infección por SARS-CoV-2. Se recolectaron casos de diferentes instituciones medicas de Colombia.

[Review of femoral component with proximal metaphyseal reconstruction using allograft cortical struts in a multioperated patient. Case report]. / Revisión de componente femoral con reconstrucción metafisaria proximal con aloinjerto óseo en lajas en paciente multioperado. Reporte de caso.

INTRODUCTION: Periprosthetic hip fractures are those that occur at the femoral and acetabular level. These fractures are associated with a wide variety of problems such as comminution, loose of bone stock and loosening of the femoral stem. Treatment of these fractures has historically been associated with high rates of treatment failures, complications and unsatisfactory outcomes. OBJECTIVE: To present the clinical-radiographic case of the treatment of a periprosthetic hip fracture, with a femoral revision and metaphyseal reconstruction with cortical strut allograft and cerclage cables, in a multioperated patient. MATERIAL AND METHODS: We present the case of a patient with a dislocation of a revision total hip prosthesis with a periprosthetic fracture type B3 of the Vancouver classification, who underwent a revision of the femoral component and a proximal metaphyseal reconstruction of the femur with cortical strut allograft and cerclage cables. RESULTS: The patient had an adequate evolution at the postoperative year, walking with a cane, radiographic control with adequate congruence of the prosthetic components and data of consolidation of the fracture. DISCUSSION: In the treatment of periprosthetic fractures, reconstruction can be done with use of cortical strut allograft and cerclage cables, with good functional and radiological results.

INTRODUCCIÓN: Las fracturas periprotésicas de cadera son aquéllas que ocurren a nivel femoral y acetabular. A estas fracturas se asocia una amplia variedad de problemas como la conminución, la pérdida ósea y con frecuencia el aflojamiento del vástago femoral. El tratamiento de estas fracturas ha estado históricamente asociado a altas tasas de fracasos del tratamiento, de complicaciones y de resultados insatisfactorios. OBJETIVO: Presentar el caso clínico-radiográfico del tratamiento de una fractura periprotésica con revisión femoral y reconstrucción metafisaria con lajas de cortical y cables de acero en un paciente multioperado. MATERIAL Y MÉTODOS: Se presenta el caso de un paciente con luxación de prótesis total de cadera izquierda de revisión + fractura periprotésica Vancouver B3, a quien se le realiza revisión de componente femoral y reconstrucción metafisaria proximal de fémur con aloinjerto óseo en lajas y fijación con cables de acero. RESULTADOS: El paciente cursa con adecuada evolución al año de postoperado, deambulando con apoyo de bastón, control radiográfico y adecuada congruencia de los componentes protésicos y datos de consolidación de la fractura. DISCUSIÓN: En el tratamiento de las fracturas periprotésicas es posible recurrir a la reconstrucción mediante el uso de aloinjertos en laja de cortical, cerclados con cables de acero, con buenos resultados funcionales y radiológicos.

[Bilateral total knee replacement]. / Reemplazo bilateral de rodilla.

Bilateral osteoarthrosis of the knee is very frequent and disabling; the treatment in severe cases is joint replacement. Bilateral condition and severe knee pain are common and the definitive treatment can be performed on both. MATERIAL AND METHODS: We reviewed the records of the first patients undergoing bilateral total knee replacement by our surgical group, between 1993-1998. RESULTS: The procedure was performed on 56 patients (112 knees) with degenerative joint disease; their age range was 60 to 82 years. The knee replacements were done either simultaneously, consecutively, or via two unique surgeries. The outcomes of each method were analyzed to assess its advantages and disadvantages. DISCUSSION: Based upon the results of the study, we find that total knee replacements done consecutively provide the best results for patients suffering from articular degeneration.

La patología degenerativa bilateral en las rodillas es muy frecuente e incapacitante; el manejo que se ofrece en los casos avanzados es el reemplazo articular por medio de una prótesis. La afección bilateral y el dolor severo de la rodilla son comunes y su tratamiento definitivo puede ser de forma bilateral. Material y métodos: Se revisaron los expedientes de los primeros pacientes operados de reemplazos bilaterales de rodilla por nuestro grupo quirúrgico, entre los años 1993 y 1998. Resultados: El procedimiento fue realizado en 56 pacientes (112 rodillas) con rango de edad de 60 a 82 años, con enfermedad articular degenerativa (EAD). Los reemplazos se llevaron a cabo de tres formas: simultánea, consecutiva y en dos tiempos. Se analizan los resultados de cada método, sus ventajas y desventajas. Discusión: En nuestra serie, practicar los reemplazos totales de rodilla en forma consecutiva es el método que mejores resultados mostró y fue el más balanceado en sus ventajas y desventajas.

Factor structure of the Beck Depression Inventory-Second Edition (BDI-II) with Puerto Rican elderly

The Beck Depression Inventory-Second Edition (BDI-II; (1) is one of the most useful measures for depressive symptomatology in many countries (2). The psychometric properties of this inventory, however, have not been reported with Puerto Rican elderly. This paper reports, exploratory psychometric results with a sample of 410 elderly Puerto Rican (65 years and older; men=94, women=316). The assessment of the construct validity of the BDI-II yielded four factors accounting for 52of total variance and an internal reliability coefficient (alpha Cronbach) of .89. A factor analysis with the 21 items of the BDI-II was performed using principal component analysis as the extraction method and Varimax rotation. This analysis revealed that the BDI-II was a good measure of the dimensions of depressive symptomatology in the present sample, which resembled prior findings reported with the general Puerto Rican Population (3). This study also reports further data supporting the reliability, validity, and practical utility of the BDI-II for the Puerto Rican population including elders. Implications for potential research with minorities and clinical uses of the BDI-II are also discussed.

Pharmacokinetics and metabolism of nateglinide in humans.

The pharmacokinetics and metabolism of nateglinide were studied in six healthy male subjects receiving a single oral (120 mg) and intravenous (60 mg) dose of [14C]nateglinide in randomized order. Serial blood and complete urine and feces were collected for 120 h post dose. Nateglinide was rapidly (approximately 90%) absorbed, with peak blood and plasma concentrations at approximately 1 h post dose. The maximal plasma concentrations of radioactivity (6360 ngEq/ml) and nateglinide (5690 ng/ml) were comparable, and plasma radioactivity concentrations were about twice those of blood at all times. Oral bioavailability was 72%, indicating only a modest first-pass effect. After either dose, plasma nateglinide concentrations declined rapidly with elimination half-lives of 1.5 to 1.7 h and plasma clearance of 7.4 l/h. Plasma radioactivity was eliminated more slowly with half-lives of 52 and 35 h in plasma and blood, respectively, after the oral dose. The contribution of this more slowly eliminated component to the AUC(0-infinity) was minor. Nateglinide was extensively metabolized, with excretion predominantly (84-87%) in urine. Only approximately 16% of the dose was excreted unchanged in urine after either dosing route. The major metabolites were the result of oxidative modifications of the isopropyl group. Three of these were monohydroxylated, two of which appeared to be diastereoisomers. Additionally, one metabolite with an unsaturation in the isopropyl group and two diol-containing isomers were identified. Glucuronic acid conjugates resulting from direct glucuronidation of the carboxylic acid were also present. The major metabolite in plasma and urine was the result of hydroxylation of the methine carbon of the isopropyl group.

Spectrophotometric determination of lithium with Quinizarin in drugs and serum.

A very sensitive analytical method is proposed for the determination of lithium based on the reaction of Li(+) ion with 1,4-dihydroxyanthraquinone (Quinizarin). In dimethylsulfoxide medium (90%) and in the presence of sodium hydroxide and sodium carbonate, a bluish-violet color (lambda(max) = 601 nm) develops and is stable over a period of 30 min to 2.5 h. The NaOH and Quinizarin concentrations were optimized simultaneously using the response surface methodology from sequential experimental Doehlert designs. Beer's law is obeyed in the concentration range 14-250 ppb Li(+) in aqueous and serum matrices, and the errors (RSD) in the determination of 100 ppb Li(+) are 4.0% and 3.9% respectively. The proposed procedure was satisfactorily applied to the determination of lithium in drugs and human serum (no deproteinization is required).

Selective spectrofluorometric determination of lithium(I) with quinizarin by extraction into tributyl phosphate.

A method for the determination of trace amounts of lithium at the ppb level has been described based on the reaction of lithium(I) with 1,4-dihydroxyanthraquinone (quinizarin) in alkaline medium, extraction into tributyl phosphate (TBP) and measurement of the fluorescence of the organic phase. A linear calibration was found in the concentration range of 9-250 ppb of lithium in aqueous solutions (lambda(exc)=590 nm, lambda(em)=670 nm) with a RSD of 2.7% for 100 ppb of lithium. After a prior treatment with potassium carbonate the method is highly specific for the analysis of lithium in presence of other inorganic ions. The proposed procedure has been applied for the determination of lithium in mineral waters, drugs and vegetables.

Metabolism of cyclosporin G in the mouse, rat, and dog.

Cyclosporin G (CsG; Sandoz compound OG 37-325) is a cyclic undecapeptide with potent, immunosuppressive activity and is currently in clinical testing for prevention of transplanted solid organ rejection. Although structurally similar to cyclosporin A (CsA), results in animals suggest that CsG has a reduced potential for nephrotoxicity when compared with CsA, while retaining equivalent therapeutic efficacy. In the present study, the major metabolic pathways of CsG in the mouse, rat, and dog were investigated using radiolabeled drug substance to determine if interspecies differences in metabolism exist. The results indicated that the major metabolic pathways in these animal species are similar to those previously reported for CsA, including oxidative modifications at amino acids 1, 4, and 9, and concomitant cyclization of amino acid 1 in two of these metabolites. Moreover, the seven major CsG metabolites (designated GM19, GM1c9, GM4N9, GM1, GM9, GM1c, and GM4N) observed in animal excreta and/or blood were identical to those identified in humans. The major circulating metabolite in blood was GM9 (9-hydroxylated CsG) in all species. In addition, numerous unidentified minor metabolites were observed. Renal excretion was a minor elimination pathway, with the majority of drug-related material excreted via the fecal route. In conclusion, CsG was found to proceed through the same metabolic pathways in three animal species and humans, and that species differences in metabolism were primarily because of differences in the relative importance of the pathways observed.

Axonal outgrowth within the abnormal scaffold of brain tracts in a zebrafish mutant.

The role of specific axonal tracts for the guidance of growth cones was investigated by examining axonal outgrowth within the abnormal brain tracts of zebrafish cyclops mutants. Normally, the earliest differentiating neurons in the zebrafish brain establish a simple scaffold of axonal tracts. Later-developing axons follow cell-specific pathways within this axonal scaffold. In cyclops embryos, this scaffold is perturbed due to the deletion of some ventromedial neurons that establish parts of the axonal scaffold and the development of an abnormal crease in the brain. In these mutant embryos, the growth cones projected by the neurons of the nucleus of the posterior commissure (nuc PC) are deprived of the two tracts of axons that they sequentially follow to first extend ventrally, then posteriorly. These growth cones respond to the abnormal scaffold in several interesting ways. First, nuc PC growth cones initially always extend ventrally as in wild-type embryos. This suggests that for the first portion of their pathway the axons they normally follow are not required for proper navigation. Second, approximately half of the nuc PC growth cones follow aberrant longitudinal pathways after the first portion of their pathway. This suggests that for the longitudinal portion of the pathway, specific growth cone/axon interactions are important for guiding growth cones. Third, although approximately half of the nuc PC growth cones follow aberrant longitudinal pathways, the rest follow normal pathways despite the absence of the axons that they normally follow. This suggests that cues independent of these axons may be capable of guiding nuc PC growth cones as well. These results suggest that different guidance cues or combinations of cues guide specific growth cones along different portions of their pathway.

Membrane-associated redox cycling of copper mediates hydroperoxide toxicity in Escherichia coli.

We are studying the action of tert-butylhydroperoxide (t-BOOH) on Escherichia coli as a model system for peroxide toxicity. In our previous report (De la Cruz-Rodriguez, L.C., Farías, R.N. and Massa, E.M. (1990) Biochim. Biophys. Acta 1015, 510-516), the respiratory chain was identified as a major target of t-BOOH. In the present paper, we study further the effect of t-BOOH on the NADH oxidase of the E. coli respiratory chain to clarify the mechanism of damage, especially regarding the identity and role of the metal ion involved. The results are: (a) t-BOOH toxicity is mediated by membrane-bound copper ions; (b) a small pool of the membrane-bound copper is reduced from Cu(II) to Cu(I) in the presence of NADH and other respiratory substrates (succinate, D-lactate); (c) this reduction of copper occurs at 37 degrees C but not at 0 degrees C or when the membranes are inactivated by previous heating; (d) the Cu(I) generated by reduction of Cu(II) during membrane preincubation with NADH, is oxidized by t-BOOH with simultaneous inactivation of the NADH oxidase, whereas treatment with only t-BOOH (without NADH) has no effect on the oxidase. It is concluded that the effect of t-BOOH on the respiratory chain is mediated by redox cycling of copper. It is proposed that the damage results from activation of the hydroperoxide through its interaction with Cu(I) in a site-specific Fenton-type reaction.

[Liver transplantation in Mexico. Report of the first successful case]. / Trasplante de hígado en México. Informe del primer caso exitoso.

This article reports the first successful human orthotopic liver transplantation performed in Mexico. The recipient was a 41 year old white male, with a history of essential hypertension and hepatitis in 1975. The diagnosis of postnecrotic cirrhosis was made in 1985 by liver biopsy. The HBsAg was negative and the functional reserve of the liver was limited (Stage "C" of the Child-Pugh classification). A liver graft was obtained through the National Cadaver Organ Transplant Program on May 2, 1988 and an orthotopic liver transplantation was performed without incidents, using the portosystemic veno-venous bypass. Inmunosuppression was carried out with triple drug therapy, cyclosporine, azathioprine, and prednisone. His postoperative course was characterized by idiopathic cholestasis, one episode of acute rejerction, arterial hypertension, renal dysfunction, esophageal herpes and inguinal lymphocele, all of which resolved. Currently the patient is alive 22 months postransplantation with normal liver function and adequate quality of life.

Human biliary metabolites of isotretinoin: identification, quantification, synthesis, and biological activity.

1. The metabolites of isotretinoin (13-cis-retinoic acid, Accutane) were investigated in the bile of two patients with biliary T-tube drainage after administration of a single, oral, 80-mg dose of 14C-isotretinoin. Radioactivity measurements showed that the two patients excreted 22.7 and 17.1% of the dose in their bile in 4 days. 2. The two major drug-related components in the bile were identified as the glucuronide conjugates of 4-oxo-isotretinoin and 16-hydroxy-isotretinoin. Two minor components were identified as the glucuronide conjugates of isotretinoin and 18-hydroxy-isotretinoin. 3. H.p.l.c. analyses of Glusulase-treated bile samples indicated that the glucuronides of isotretinoin and the two major metabolites accounted for about 48% and 44% of the total radioactivity in the bile of the two patients. 4. Racemic 16-hydroxy-isotretinoin was synthesized and evaluated for its effect on human sebocytes in vitro. This metabolite and the other major metabolites of isotretinoin were less active than isotretinoin in inhibiting the proliferation of the sebocytes.

Damage of Escherichia coli cells by t-butylhydroperoxide involves the respiratory chain but is independent of the presence of oxygen.

The action of t-butylhydroperoxide (tBOOH) on Escherichia coli cells has been studied as a model system for organic peroxide toxicity. Exposure of E. coli cells to tBOOH led to progressive and irreversible impairment of the respiratory function, an effect which was dependent on the availability of substrate. The effect of tBOOH on growth of E. coli with different carbon sources and alternative terminal electron acceptors was investigated. It was found that the sensitivity of E. coli to tBOOH under diverse growth conditions implicating a functional respiratory chain was greater than when the bacterium grew by fermentation. Also the mutant E. coli SASX76, which requires exogenous 5-aminolevulinic acid to synthesize the cytochromes, was more resistant to tBOOH when lacking a functional respiratory chain. These data point to the respiratory chain as a major target in the in vivo action of tBOOH. Experiments with isolated membranes also showed a tBOOH-induced damage of the respiratory chain monitored by impairment of the NADH oxidase. The effect of tBOOH was produced even under anaerobiosis, indicating that development of cell damage was independent of oxygen and, therefore, that neither oxygen-derived radicals nor lipid peroxidation were involved.

Identification of etretinate metabolites in human blood.

Five metabolites were isolated from the blood of psoriatic patients on chronic therapy with etretinate (Tegison). The two major metabolites were the all-trans acid (acitretin) and the 13-cis acid (isoacitretin), both of which had been previously identified as major metabolites of etretinate in human blood. The other three metabolites had not been previously reported in human blood. One metabolite corresponded to isoacitretin with a hydroxy group on an aromatic methyl group. The other two metabolites had acid side chains shortened by one carbon and a reduced 11, 12-double bond. One of the two metabolites retained the aromatic methoxy group, whereas the other was the phenolic analog.

Identification of etretinate metabolites in human bile.

The metabolites of etretinate (Tegison) were investigated in bile obtained from two patients with biliary T-tubes. Bile samples were collected for 5 days after administration of a single, oral 100-mg dose of 14C-labeled etretinate. Radioactivity measurements indicated that the two patients excreted 9.6% and 8.0% of the dose in the 5-day bile. The etretinate metabolites in the bile were present mainly as beta-glucuronidase-labile conjugates. HPLC analyses of the beta-glucuronidase-treated bile samples showed no measurable concentrations (less than 10 ng/ml) of etretinate or the 13-cis acid, isoacitretin. Acitretin, the free acid of etretinate, was present and accounted for about 0.9% of the biliary radioactivity. The major portion of the radioactivity in the extracts of the beta-glucuronidase-treated bile samples consisted of two metabolites with shortened side chains. One was identified as the 11, 12-dihydro-13, 14, 15, 20-tetranor phenolic derivative of acitretin, which was previously identified as a human urinary metabolite. The other metabolite was identified as the 11, 12, 13, 14-tetrahydro-15-nor phenolic derivative of acitretin, which has not been previously identified as a metabolite of etretinate.