Guillain-Barré Syndrome and COVID-19 Vaccine: A Multicenter Retrospective Study of 46 Cases.

ABSTRACT: In the context of the global vaccination campaign against COVID-19, several cases of postvaccinal Guillain-Barré syndrome (GBS) were reported. Whether a causal relationship exists between these events has yet to be established. We investigated the clinical and electromyographic characteristics of patients who developed GBS after COVID-19 vaccination and compare these with findings in patients with GBS, without a history of recent vaccination. We included 91 cases between March 2020 and March 2022, treated at 10 referral hospitals of Buenos Aires, Argentina. Of these, 46 had received vaccination against COVID-19 within the previous month. Although Medical Research Council sum-scores were similar in both groups (median 52 vs. 50; P = 0.4), cranial nerve involvement was significantly more frequent in the postvaccination group (59% vs. 38%; P = 0.02), as was bilateral facial paralysis (57% vs. 24%; P = 0.002). No differences were found in clinical or neurophysiological phenotypes, although 17 subjects presented the variant of bilateral facial palsy with paresthesias (11 vs. 6; P = 0.1); nor were significant differences observed in length of hospital stay or mortality rates. Future vaccine safety monitoring and epidemiology studies are essential to demonstrate any potential causal relationship between these events.

Understanding Progestins: From Basics to Clinical Applicability.

Progestin is a term used to describe a synthetic progestogen. The activity and potency of synthetic progestins are mostly evaluated via parameters associated with their endometrial effects, which are related to their interactions with progesterone, estrogen, androgen, glucocorticoid, and mineralocorticoid receptors. The chemical structure of progestins is the key to understanding their interactions with these receptors and predicting the other effects associated with these drugs. Due to their endometrial effect, progestins are used for different gynecological conditions, such as endometriosis, contraception, hormonal replacement therapy, and artificial reproduction techniques. This review is focused on improving our knowledge of progestins (from their history and biochemical effects related to their chemical structures to clinical applications in gynecological conditions) in order to improve clinical practice.

Correlation Between Hemoglobin Glycation Index Measured by Continuous Glucose Monitoring With Complications in Type 1 Diabetes.

OBJECTIVE: HbA1C is the "gold standard" parameter to evaluate glycemic control in diabetes; however, its correlation with mean glucose is not always perfect. The objective of this study was to correlate continuous glucose monitoring (CGM)-derived hemoglobin glycation index (HGI) with microvascular complications. METHODS: We conducted a cross-sectional study including permanent users of CGM with type 1 diabetes mellitus or latent autoimmune diabetes of the adult. HGI was estimated, and presence of microvascular complications was compared in subgroups with high or low HGI. A logistic regression analysis to assess the contribution of high HGI to chronic kidney disease (CKD) was performed. RESULTS: In total, 52 participants who were aged 39.7 ± 14.7 years, with 73.1% women and 15.5 years (IQR, 7.5-29 years) since diagnosis, were included; 32.7% recorded diabetic retinopathy, 25% CKD, and 19.2% neuropathy. The median HbA1C was 7.6% (60 mmol/mol) and glucose management indicator (GMI) 7.0% (53 mmol/mol). The average HGI was 0.55% ± 0.66%. The measured HbA1C was higher in the group with high HGI (8.1% [65 mmol/mol] vs 6.9% [52 mmol/mol]; P < .001), whereas GMI (7.0% [53 mmol/mol] vs 7.0% [53 mmol/mol]; P = .495) and mean glucose were similar in both groups (153 mg/dL vs 153 mg/dL; P = .564). In the high HGI group, higher occurrence of CKD (P = .016) and neuropathy were observed (P = .025). High HGI was associated with increased risk of CKD (odds ratio [OR]: 5.05; 95% CI: 1.02-24.8; P = .04) after adjusting for time since diagnosis (OR: 1.09; 95% CI: 1.02-1.16; P = .008). CONCLUSION: High HGI measured by CGM may be a useful marker for increased risk of microvascular diabetic complications.

Association of estimated glucose disposal rate and chronic diabetic complications in patients with type 1 diabetes.

INTRODUCTION: The role of insulin resistance in diabetic chronic complications among individuals with type 1 diabetes (T1D) has not been clearly defined. The aim of this study was to examine the performance of insulin resistance, evaluated using the estimated glucose disposal rate (eGDR) for the identification of metabolic syndrome (MS) and diabetic chronic complications. METHODS: Cross-sectional study in a tertiary care centre. We included patients of 18 years and older, with at least 6 months of T1D duration. Anthropometric, clinical and biochemical data were collected. RESULTS: Seventy patients, 41 (58.6%) women, with a median age of 36.6 years (range 18-65). Mean age of onset and duration of diabetes was 13.5 ± 6.5 and 23.6 ± 12.2 years, respectively. Twenty-one (30%) patients met the metabolic syndrome (MS) criteria. Patients with MS had lower eGDR compared to patients without (5.17 [3.10-8.65] vs. 8.86 [6.82-9.85] mg/kg/min, respectively, p = .003). Median eGDR in patients with nephropathy, retinopathy and neuropathy compared with those without was 6.75 (4.60-8.20) versus 9.53 (8.57-10.3); p < .001, 6.45 (4.60-7.09) versus 9.50 (8.60-10.14); p < .001, 5.56 (4.51-6.81) versus 9.49 [8.19-10.26] mg/kg/min; p < .001, respectively. The eGDR showed an area under the curve of 0.909, 0.879, 0.897 and 0.836 for the discrimination of MS, retinopathy, neuropathy and nephropathy, respectively. CONCLUSIONS: Patients with T1D diabetic complications have higher insulin resistance. The eGDR discriminates patients with chronic diabetic complications and MS. While more ethnic-specific studies are required, this study suggests the possibility to incorporate eGDR into routine diabetes care.

Diagnosis of Rapidly Progressive Dementia in a Referral Center in Argentina.

INTRODUCTION: Rapidly progressive dementia (RPD) is a broadly defined clinical syndrome. Our aim was to describe clinical and ancillary study findings in patients with RPD and evaluate their diagnostic performance for the identification of nonchronic neurodegenerative rapidly progressive dementia (ncnRPD). METHODS: We reviewed clinical records and ancillary methods of patients evaluated for RPD at our institution in Buenos Aires, Argentina from 2011 to 2017. We compared findings between chronic neurodegenerative RPD and ncnRPD and evaluated the diagnostic metrics using receiver operating characteristic curves. RESULTS: We included 104 patients with RPD, 29 of whom were chronic neurodegenerative RPD and 75 of whom were ncnRPD. The 6-month time to dementia cutpoint had a sensitivity of 89% and specificity of 100% for ncnRPD, with an area under the receiver operating characteristic curve of 0.965 (95% confidence interval=0.935-0.99; P<0.001). A decision tree that included time to dementia, brain magnetic resonance imaging, and cerebrospinal fluid analysis identified ncnRPD patients with a sensitivity of 100%, specificity of 79%, positive predictive value of 93%, and negative predictive value of 100% overall. DISCUSSION: RPD is a clinical syndrome that comprises different diagnoses, many of them for treatable diseases. Using the time to dementia, brain magnetic resonance imaging, and cerebrospinal fluid analysis when triaging these patients could help identify those diseases that need to be studied more aggressively.

Cerebellar Ataxia With Extreme Photophobia Associated With Anti-SOX1 Antibodies.

Anti-SOX1 antibodies are associated with diverse neurological syndromes, targeting both the central (paraneoplastic cerebellar degeneration) and peripheral nervous systems (Lambert Eaton myasthenic syndrome, paraneoplastic neuropathy). Although the pathogenic role of these antibodies remains unclear, their strong association with underlying neoplastic disease (mainly small-cell lung cancer) has designated them as onconeural antibodies. Here, we present a case of cerebellar ataxia with marked photophobia, with severe atrophy of the cerebellum and brain stem, associated with anti-SOX1 antibodies without evidence of an underlying malignancy. Although anti-SOX1-associated cerebellar syndrome is infrequent, investigation of these antibodies should be considered as a part of the diagnostic algorithm if more common causes have been ruled out. Extensive brain stem lesions causing disruption of the trigeminal pathway and its connections with the pretectal area might explain the underlying mechanism of the associated photophobia. Early recognition of anti-SOX1 antibodies, exclusion of underlying neoplasm, and prompt initiation of immunotherapy are essential to achieve a better outcome.

[Retrospective study of 48 cases of primary central nervous system lymphoma]. / Estudio retrospectivo de 48 casos de linfoma primario del sistema nervioso central.

Primary central nervous system lymphoma (PCNSL) is an infrequent form of non-Hodgkin lymphoma restricted to the CNS. More than 90% are type B and mainly affect patients aged 50-70 years. Immunodeficiency is the most important risk factor. The aim of our study was to evaluate the immune status, clinical presentation and findings in complementary studies of PCNSL patients. A retrospective analysis of 48 cases treated in our center between January 1992 and May 2015 was performed. Median age at diagnosis was 61 years (range 25-84); with male predominance (2.1:1). Forty one cases (85%) were immunocompetent patients. Brain MRI findings showed parenchymal involvement in 45 cases (94%), 43% with frontal lobe and 35% basal ganglia, 4% had meningeal involvement and 2% had ophthalmic involvement at diagnosis. Fifty-five percent had restricted signal on diffusion weighted imaging and contrast enhancement was found in 89%. Pyramidal syndrome was the main initial clinical manifestation (56%). There were abnormal findings in 62% of CSF samples, but in only 11.1% positive cytology results were detected. The most frequent type was diffuse large B-cell lymphoma (83%), being B-cell type the most common form between them (96%). In our series PCNSL was more frequent in immunocompetent elderly male subjects. At initial evaluation, clinical manifestations and MRI findings were variable. The initial suspicion of this entity would allow an early diagnosis, avoiding empirical treatments that may confuse or delay diagnosis.

Estudio restrospectivo de 48 casos de linfoma primario del sistema nervioso central / Retrospective study of 48 cases of primary central nervous system lymphoma

Los linfomas primarios del sistema nervioso central (LPSNC) son neoplasias infrecuentes confinadas al SNC. Más del 90% son de tipo B y afectan principalmente a pacientes entre 50-70 años. La inmunodeficiencia es el factor de riesgo más importante. El objetivo de nuestro trabajo fue evaluar las características demográficas, estado inmunológico y los hallazgos en los estudios complementarios de pacientes con LPSNC. Se realizó el análisis retrospectivo de 48 casos estudiados en nuestro centro desde enero 1992 a mayo 2015. La edad mediana de presentación fue 61 años (25-84); la relación hombre:mujer 2.1:1. El 85% (41 casos) fueron inmunocompetentes al momento del diagnóstico. El 94% (45 casos) tuvo compromiso parenquimatoso, 4% (2 casos) meníngeo y 2% (1 caso) ocular. El lóbulo más afectado fue el frontal (43%) y 35% tuvieron compromiso ganglio basal. En RM, el 89% mostró realce con contraste y 55% restricción en difusión. El síndrome piramidal fue la manifestación inicial más frecuente (56%). El LCR fue inflamatorio en el 72%, aunque solo 11.1% presentó examen citológico positivo. El tipo más frecuente de LPSNC fue no-Hodgkin B (96%) y el subtipo difuso de células grandes el más habitual (83%). En nuestra serie la ausencia de inmunocompromiso fue una característica frecuente y la presentación clínico-radiológica fue muy pleomórfica. La sospecha inicial permitiría arribar a un diagnóstico temprano, evitando tratamientos empíricos que puedan confundir o retrasar el diagnóstico.

Primary central nervous system lymphoma (PCNSL) is an infrequent form of non-Hodgkin lymphoma restricted to the CNS. More than 90% are type B and mainly affect patients aged 50-70 years. Immunodeficiency is the most important risk factor. The aim of our study was to evaluate the immune status, clinical presentation and findings in complementary studies of PCNSL patients. A retrospective analysis of 48 cases treated in our center between January 1992 and May 2015 was performed. Median age at diagnosis was 61 years (range 25-84); with male predominance (2.1:1). Forty one cases (85%) were immunocompetent patients. Brain MRI findings showed parenchymal involvement in 45 cases (94%), 43% with frontal lobe and 35% basal ganglia, 4% had meningeal involvement and 2% had ophthalmic involvement at diagnosis. Fifty-five percent had restricted signal on diffusion weighted imaging and contrast enhancement was found in 89%. Pyramidal syndrome was the main initial clinical manifestation (56%). There were abnormal findings in 62% of CSF samples, but in only 11.1% positive cytology results were detected. The most frequent type was diffuse large B-cell lymphoma (83%), being B-cell type the most common form between them (96%). In our series PCNSL was more frequent in immunocompetent elderly male subjects. At initial evaluation, clinical manifestations and MRI findings were variable. The initial suspicion of this entity would allow an early diagnosis, avoiding empirical treatments that may confuse or delay diagnosis.

[Subcutaneous immunoglobulin. Treatment in chronic inflammatory demyelinating polyradiculo-neuropathy]. / Inmunoglobulina subcutánea. Tratamiento en polineuropatía desmielinizante inflamatoria crónica.

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an acquired disease that may affect nerve roots and peripheral nerves. Despite its low incidence, diagnosis is particularly important because there are different effective treatments. Human immunoglobulin is one of the mainstays of the treatment. Although there are few studies up to date, subcutaneous immunoglobulin (IgSC) has been proposed as an alternative to intravenous administration with similar efficacy. We present three cases with definite CIDP, classified according to the European Federation of Neurological Societies / Peripheral Nerve, Society (EFNS /PNS) criteria in which was used SCIgG as a treatment after success with the intravenous route. The Overall Neuropathy Limitations Scale (ONLS) was used to estimate the changes in the muscular strength before and after treatment.

Inmunoglobulina subcutánea: Tratamiento en polineuropatía desmielinizante inflamatoria crónica / Subcutaneous immunoglobulin. Treatment in chronic inflammatory demyelinating polyradiculo-neuropathy

La polineuropatía desmielinizante inflamatoria crónica (CIDP) es una enfermedad adquirida que puede afectar a raíces, plexos y nervios periféricos. A pesar de su baja incidencia, su diagnóstico cobra especial relevancia dado que actualmente existen tratamientos efectivos para la misma. La gammaglobulina humana endovenosa (IVIgG) es, junto con los esteroides y la plasmaféresis, uno de los tratamientos de primera elección. La vía de administración subcutánea se ha propuesto como una alternativa novedosa frente a la administración endovenosa con una eficacia similar. Presentamos tres casos de CIDP definitiva, clasificados según los criterios de la European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) en los cuales se utilizó tratamiento crónico con inmunoglobulina subcutánea (IgSC). Todos ellos habían recibido tratamiento previo con IVIgG. Se obtuvo mejoría de la fuerza evaluada por Overall Neuropathy Limitations Scale (ONLS) y los tres pacientes manifestaron una mejor adaptación a sus actividades de la vida diaria.

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an acquired disease that may affect nerve roots and peripheral nerves. Despite its low incidence, diagnosis is particularly important because there are different effective treatments. Human immunoglobulin is one of the mainstays of the treatment. Although there are few studies up to date, subcutaneous immunoglobulin (IgSC) has been proposed as an alternative to intravenous administration with similar efficacy. We present three cases with definite CIDP, classified according to the European Federation of Neurological Societies / Peripheral Nerve, Society (EFNS /PNS) criteria in which was used SCIgG as a treatment after success with the intravenous route. The Overall Neuropathy Limitations Scale (ONLS) was used to estimate the changes in the muscular strength before and after treatment.

Low familial risks for multiple sclerosis in Buenos Aires, Argentina.

BACKGROUND: Multiple sclerosis is a complex disease in which genetic susceptibility plays a role and familial occurrence has long been recognized. To date, no studies of familial occurrence have been conducted in Argentina, a country with low to intermediate prevalence. METHODS: As part of a cross-sectional study on multiple sclerosis in Buenos Aires, immediate and extended pedigree details were collected on 219 patients. Crude and age-adjusted recurrence risks for patient relatives were also assessed. RESULTS: Details on age or age of death and disease status were obtained for 4227 relatives. Ten percent of patients reported at least one relative with MS diagnosis, the highest risk (1.54%) was observed in daughters of patients who presented 92-times greater risk than the general population. Sibling recurrence risk ratio was similar to that reported in other locations. CONCLUSIONS: Relatives of patients with MS living in Argentina are at greater risk of developing the disease, although not as high as the risk reported for other geographic regions.

Autoimmune disease prevalence in a multiple sclerosis cohort in Argentina.

Background. Comorbid autoimmune diseases in MS patients have been studied extensively with controversial results. Moreover, no such data exists for Latin-American MS patients. Methods. We conducted a case-control study aimed to establish the prevalence of autoimmune disorders in a cohort of Argentinean MS patients. Results. There were no significant differences in autoimmune disease prevalence in MS patients with respect to controls. The presence of one or more autoimmune disorders did not increase risk of MS (OR 0.85, 95% CI 0.6-1.3). Discussion. Our results indicate absence of increased comorbid autoimmune disease prevalence in MS patients, as well as of increased risk of MS in patients suffering from other autoimmune disorders.

A redução à prova da experiência

O artigo apresenta uma nova descrição da épochè que se apóia em uma mudança de paradigma quanto ao estatuto da fenomenologia. Substituindo o enfoque hermenêutico tradicional pela abordagem pragmática, o artigo define três componentes da épochè: a suspensão, a conversão e o deixar-vir(AU)

Color vision in the comb frequency domain.

In 1982, Horace Barlow considered the question of human trichromacy in the context of information theory: according to the Sampling Theorem, three types of receptors covering the visible spectrum (400-700 nm) might be sufficient to reconstruct the color signal. Although Barlow was led to reject the direct application of the Sampling Theorem to explain color dimensionality, the theoretical framework offers a fresh point of view for analyzing the color system in conjunction with the physical characteristics of natural color signals. This review aims to illustrate that if the strict mathematical reconstruction (as implied by the Sampling Theorem) is replaced by a pragmatic approximation of color signals, then trichromacy, with its subsequent opponent-color process, could be regarded as an optimization of color constancy abilities in the spectral environment of primates. Higher dimension systems (tetrachromacy) found in other species can also serve the purpose of color constancy optimization in environments where color signals exhibit a finer spectral structure.