Modernizing the evaluation of infantile nystagmus: the role of handheld optical coherence tomography.

BACKGROUND: Infantile nystagmus syndrome can be associated with an afferent problem (anterior or posterior segment) or constitute an isolated idiopathic disorder. With a normal ophthalmic examination, current guidelines recommend electroretinography (ERG) rather than magnetic resonance (MRI) for preliminary workup. Given the limited use of optical coherence tomography (OCT) in preverbal children, the purpose of this study was to evaluate the role of handheld OCT (HH-OCT) in the initial diagnostic evaluation of infantile nystagmus. METHODS: In this cross-sectional case series, the medical records of all children with infantile nystagmus and HH-OCT imaging at the Duke Eye Center from August 2016 to July 2021 were retrospectively reviewed. Children with anterior segment disorders or obvious retina/optic nerve structural pathology, bilateral ophthalmoplegia, or Down syndrome were excluded. Two masked pediatric ophthalmologists graded HH-OCT images for optic nerve head and macular abnormalities. A neuro-ophthalmologist reviewed clinical findings of each patient's presenting visit and recommended appropriate testing (MRI vs ERG), initially without, and again with HH-OCT image review. RESULTS: A total of 39 cases were included, with mean presenting age of 1.3 years. Final diagnoses included retinal or foveal abnormalities (7), optic nerve pathology (13), idiopathic (10), or unknown (9). HH-OCT findings included optic nerve hypoplasia (1), optic nerve elevation (3), persistence of the inner layers at the fovea (9), thin ganglion cell layer (8), ellipsoid zone abnormality (3), and thin choroid (1). HH-OCT findings altered initial clinical-only management in 16 cases (41%), including avoiding MRI (5) and ERG (10) testing. CONCLUSIONS: Our results suggest that HH-OCT has the potential to augment and streamline the evaluation of infantile nystagmus.

Blastocystis hominis -Associated Acute Appendicular Peritonitis in a 9-Year-Old Boy: A Case Report and a Comprehensive Review of the Literature.

Although Blastocystis sp. has been classically considered a commensal parasite with limited pathogenicity, recent studies suggest that its pathogenic potential is high. We report the case of a 9-year-old Spanish male who presented with peritonitis secondary to acute appendicitis with abundant intra-abdominal turbid-free fluid. A standard appendectomy was performed, and a sample of the fluid was taken for microbiological culture. Multimicrobial flora was isolated in peritoneal fluid culture. The antibiotic resistance study showed that all the microorganisms were sensitive to meropenem. On the 5th postoperative day, a control blood test showed relative eosinophilia and a persistently elevated C-reactive protein. A stool parasitological study showed abundant cysts morphologically compatible with Blastocystis hominis . The hematoxylin & eosin and Giemsa study identified abundant parasitic cysts in the appendix. The patient evolved favorably and is currently asymptomatic and under follow-up. Regarding acute appendicitis, there is only one report in the literature of peritonitis of appendiceal origin associated with Blastocystis sp. In conclusion, although infrequent, parasitosis should be considered as a potential etiological agent of acute appendicitis, even in nonendemic areas. Relative eosinophilia or persistently elevated acute phase reactants despite adequate antibiotic coverage should help to establish diagnostic suspicion.

Mitochondrial targeted catalase improves muscle strength following arteriovenous fistula creation in mice with chronic kidney disease.

Hand dysfunction is a common observation after arteriovenous fistula (AVF) creation for hemodialysis access and has a variable clinical phenotype; however, the underlying mechanism responsible is unclear. Grip strength changes are a common metric used to assess AVF-associated hand disability but has previously been found to poorly correlate with the hemodynamic perturbations post-AVF placement implicating other tissue-level factors as drivers of hand outcomes. In this study, we sought to test if expression of a mitochondrial targeted catalase (mCAT) in skeletal muscle could reduce AVF-related limb dysfunction in mice with chronic kidney disease (CKD). Male and female C57BL/6J mice were fed an adenine-supplemented diet to induce CKD prior to placement of an AVF in the iliac vascular bundle. Adeno-associated virus was used to drive expression of either a green fluorescent protein (control) or mCAT using the muscle-specific human skeletal actin (HSA) gene promoter prior to AVF creation. As expected, the muscle-specific AAV-HSA-mCAT treatment did not impact blood urea nitrogen levels (P = 0.72), body weight (P = 0.84), or central hemodynamics including infrarenal aorta and inferior vena cava diameters (P > 0.18) or velocities (P > 0.38). Hindlimb perfusion recovery and muscle capillary densities were also unaffected by AAV-HSA-mCAT treatment. In contrast to muscle mass and myofiber size which were not different between groups, both absolute and specific muscle contractile forces measured via a nerve-mediated in-situ preparation were significantly greater in AAV-HSA-mCAT treated mice (P = 0.0012 and P = 0.0002). Morphological analysis of the post-synaptic neuromuscular junction uncovered greater acetylcholine receptor cluster areas (P = 0.0094) and lower fragmentation (P = 0.0010) in AAV-HSA-mCAT treated mice. Muscle mitochondrial oxidative phosphorylation was not different between groups, but AAV-HSA-mCAT treated mice had lower succinate-fueled mitochondrial hydrogen peroxide emission compared to AAV-HSA-GFP mice (P < 0.001). In summary, muscle-specific scavenging of mitochondrial hydrogen peroxide significantly improves neuromotor function in mice with CKD following AVF creation.

The Gender Minority Stress and Resilience Measure: Psychometric Validity for Use in Spanish.

Purpose: Stigma is a fundamental driver of HIV disparities among transgender women (TW). The gender minority stress and resilience (GMSR) measure has not been validated in Spanish-speaking, resource-limited settings. We examined the psychometric properties of a translated and abbreviated GMSR among TW in Tijuana, Mexico. Methods: From 2020 to 2021, 152 participants were recruited through social media and venue-based sampling. We collected information on the abbreviated GMSR, psychosocial factors (e.g., depressive symptoms), and sociodemographics. The abbreviated GMSR assessed 7 factors (Discrimination, Rejection, Internalized Transphobia, Negative Expectations, Nondisclosure, Pride, and Community Connectedness). Confirmatory factor analysis, Cronbach's alphas, and McDonald's omegas assessed structural validity. Pearson's partial correlations assessed criterion, convergent, and discriminant validities. Results: The 7-factor structure solution had acceptable fit (root mean square error of approximation [95% confidence interval]=0.05 [0.05-0.06]; comparative fit index/Tucker-Lewis index=0.92/0.91); and internal reliability (α=0.62-0.89; ω=0.62-0.89). Depressive (r=0.22-0.43; p<0.001-0.007), post-traumatic stress disorder (PTSD; r=0.20-0.34; p<0.001-0.017) symptoms, and perceived stress (r=0.19-0.41; p≤0.001-0.030) were all positively associated with all stress factors (e.g., Discrimination, Rejection, Internalized Transphobia, Negative Expectations, and Nondisclosure). The resilience factor Pride was associated with fewer PTSD symptoms (r=-0.18; p=0.027), lower perceived life stress (r=-0.21; p=0.012), and greater general resilience (r=0.26; p=0.002). The Community Connectedness resilience factor was associated with fewer depressive symptoms (r=-0.22; p=0.007). Constructs were conceptually distinct with factor correlations below 0.60. Conclusion: Findings suggest that the Spanish-translated, abbreviated GMSR is a reliable and valid measure. These data expand the usability of the GMSR to TW in a Latin American, Spanish-speaking context.

Effective Treatment of Patients Experiencing Primary, Acute HIV Infection Decreases Exhausted/Activated CD4+ T Cells and CD8+ T Memory Stem Cells.

Several studies have identified main changes in T- and B-lymphocyte subsets during chronic HIV infection, but few data exist on how these subsets behave during the initial phase of HIV infection. We enrolled 22 HIV-infected patients during the acute stage of infection before the initiation of antiretroviral therapy (ART). Patients had blood samples drawn previous to ART initiation (T0), and at 2 (T1) and 12 (T2) months after ART initiation. We quantified cellular HIV-DNA content in sorted naïve and effector memory CD4 T cells and identified the main subsets of T- and B-lymphocytes using an 18-parameter flow cytometry panel. We identified correlations between the patients' clinical and immunological data using PCA. Effective HIV treatment reduces integrated HIV DNA in effector memory T cells after 12 months (T2) of ART. The main changes in CD4+ T cells occurred at T2, with a reduction of activated memory, cytolytic and activated/exhausted stem cell memory T (TSCM) cells. Changes were present among CD8+ T cells since T1, with a reduction of several activated subsets, including activated/exhausted TSCM. At T2 a reduction of plasmablasts and exhausted B cells was also observed. A negative correlation was found between the total CD4+ T-cell count and IgM-negative plasmablasts. In patients initiating ART immediately following acute/early HIV infection, the fine analysis of T- and B-cell subsets has allowed us to identify and follow main modifications due to effective treatment, and to identify significant changes in CD4+ and CD8+ T memory stem cells.

Risk Factors Leading to Enucleation or Evisceration in Infectious Endophthalmitis.

Endophthalmitis treatment consists of intravitreal antibiotics injections and, in selected circumstances, pars plana vitrectomy. However, severe or refractory cases may require an enucleation or evisceration (ENEV). Our study seeks to identify risk factors leading to enucleation or evisceration in patients with infectious endophthalmitis. A retrospective chart review of subjects with a clinical diagnosis of infectious endophthalmitis was undertaken. The affected eyes were stratified into groups: those that underwent ENEV and those in which the eyeball was preserved (EP). The groups were compared using statistical analyses. In total, 69 eyes diagnosed with infectious endophthalmitis were included in the study. There was a higher frequency of exogenous infectious endophthalmitis in the ENEV group versus the EP group. Postsurgical infectious endophthalmitis was lower in the ENEV than in the EP group. A visual acuity of no light perception was more common in the ENEV compared to the EP group. Panophthalmitis was more frequent in the ENEV versus the EP group. Our findings suggest that eyes with endophthalmitis presenting with a visual acuity of no light perception, panophthalmitis, or exogenous etiology have a higher risk of requiring ENEV. In addition, eyes with a postsurgical etiology may be at a lower risk of requiring ENEV.

Dynamics and Dispersal of Local Human Immunodeficiency Virus Epidemics Within San Diego and Across the San Diego-Tijuana Border.

BACKGROUND: Evolutionary analyses of well-annotated human immunodeficiency virus (HIV) sequence data can provide insights into viral transmission patterns and associated factors. Here, we explored the transmission dynamics of the HIV-1 subtype B epidemic across the San Diego (US) and Tijuana (Mexico) border region to identify factors that could help guide public health policy. METHODS: HIV pol sequences were collected from people with HIV in San Diego County and Tijuana between 1996-2018. A multistep phylogenetic approach was used to characterize the dynamics of spread. The contributions of geospatial factors and HIV risk group to the local dynamics were evaluated. RESULTS: Phylogeographic analyses of the 2034 sequences revealed an important contribution of local transmission in sustaining the epidemic, as well as a complex viral migration network across the region. Geospatial viral dispersal between San Diego communities occurred predominantly among men who have sex with men, with central San Diego being the main source (34.9%) and recipient (39.5%) of migration events. HIV migration was more frequent from San Diego county towards Tijuana than vice versa. Migrations were best explained by the driving time between locations. CONCLUSIONS: The US-Mexico border may not be a major barrier to the spread of HIV, which may stimulate coordinated transnational intervention approaches. Whereas a focus on central San Diego has the potential to avert most spread, the substantial viral migration independent of central San Diego shows that county-wide efforts will be more effective. Combined, this work shows that epidemiological information gleaned from pathogen genomes can uncover mechanisms that underlie sustained spread and, in turn, can be a building block of public health decision-making.

Characteristics, Upon Presentation, of a Cohort of Hispanic Patients with Birdshot Retinochoroidopathy.

OBJECTIVE: To describe the characteristics, upon presentation, of a cohort of Hispanic patients with birdshot retinochoroidopathy. METHODS: A retrospective chart review of Hispanic patients with birdshot retinochoroidopathy of was performed. The demographic and clinical characteristics were analyzed. RESULTS: Nine patients who met the research criteria for a diagnosis of birdshot retinochoroidopathy were identified and included in the analysis, all of whom were HLA-A29 positive. The median age of the cohort upon presentation was 52 years; 89% of the patients were female, and all were Hispanics. Ninety-four percent of the eyes had an initial visual acuity of 20/50 or better, while 72% had measured 20/25 or better. Sixty-one percent of the eyes had retinal vasculitis, which was bilateral in 83% of the cases. Thirty-three percent of the patients had, upon presentation, evidence of cystoid macular edema, which was always bilateral. All the eyes had the typical birdshot lesions, at presentation. CONCLUSION: Birdshot retinochoroidopathy can be found in Hispanic patients. Our study suggests that the characteristics upon presentation in Hispanics may be similar to those of Caucasian cohorts.

Clinical, Imaging, and Laboratory Characteristics of Adult Mexican Patients with Tuberculous Meningitis: A Retrospective Cohort Study.

Tuberculous Meningitis (TBM) is the most common form of central nervous system Tuberculosis (TB), accounting for 5-6% of extrapulmonary TB cases. Nowadays, TBM continues to be a major topic in public health because of its high prevalence worldwide. This retrospective study aimed to describe the clinical, laboratory, and imaging characteristics at admission; and in-hospital outcome of adult Mexican patients with TBM. We collected data from medical records of patients aged ≥18 years diagnosed with TBM according to the uniform case definition for clinical research who were treated at Tijuana General Hospital between January 2015 and March 2018 and compared them according to the subtype of diagnosis. We included 41 cases (26 males, median age 28 years, range 18-57 years), 13 (31.7%) patients were HIV positive, and 21 (51.2%) were illicit drug users. At admission, 7 (17.1%) patients were in stage I, 22 (53.6%) in stage II, and 12 (29.3%) in stage III. A definitive diagnosis was established in 23 (56.1%) patients, probable in 14 (34.1%), and possible in four (9.8%). Molecular testing was positive in 83% of the cases, yielding significantly higher positive results than other microbiological studies. There were eight (19.5%) deaths, without statistical difference between mortality and not having a definitive diagnosis (p = 0.109). We found that the baseline characteristics of our population were similar to those described by other authors worldwide. In this series, molecular testing showed to be very useful when used in the early stages, particularly in subjects with subacute onset of headache, fever, weight loss, and altered mental status.

Single-Crystal Electrochemistry Reveals Why Metal Nanowires Grow.

Shape-control is used to tune the properties of metal nanostructures in applications ranging from catalysts to touch screens, but the origins of anisotropic growth of metal nanocrystals in solution are unknown. We show single-crystal electrochemistry can test hypotheses for why nanostructures form and predict conditions for anisotropic growth by quantifying the degree to which different species cause facet-selective metal deposition. Electrochemical measurements show disruption of alkylamine monolayers by chloride ions causes facet-selective Cu deposition. An intermediate range of chloride concentrations maximizes facet-selective Cu deposition on single crystals and produces the highest aspect ratio nanowires in a solution-phase synthesis. DFT calculations similarly show an intermediate monolayer coverage of chloride displaces the alkylamine capping agent from the ends but not the sides of a nanowire, facilitating anisotropic growth.

Histoplamosis diseminada en una paciente con hipotiroidismo / Disseminated histoplasmosis in a patient with hypothyroidism

La histoplasmosis es una infección causada por el hongo Histoplasma capsulatum, la incidencia de la enfermedad oscila entre 0.1 a 0.29 casos por cada 100 000 habitantes y de estos 1 de cada 2 000 casos se presenta de forma diseminada, manifestándose en personas con inmunosupresión y de forma infrecuente en personas inmunocompetentes. Objetivo: mostrar la relación existente entre hipotiroidismo e histoplasmosis diseminada. Presentación del caso clínico: paciente de 33 años, procedente de Talanga, Francisco Morazán, Honduras, tratada por hipotiroidismo de 3 años de evolución con levotiroxina 100ug cada día, con tumoración en axila izquierda de hace 2 años, la cual 3 meses previos al ingreso fue tratada por adenitis aguda de forma ambulatoria sin mostrar mejoría. Al examen físico se encontró adenopatía de 2 sospecha de histoplasmosis confirmándose con tinción de Grocott; el examen para virus de inmunodeficiencia humana fue negativo y el perfil inmunológico resultó normal. Conclusión : En este caso la histoplasmosis diseminada se acompañó de hipotiroidismo, no se ha demostrado que conlleve a inmunosupresión, y aún faltan pruebas que establezcan el vínculo de hipotiroidismo como factor predisponente a esta enfermedad...(AU)

HIV pretreatment drug resistance trends in three geographic areas of Mexico.

BACKGROUND: Pretreatment drug resistance (PDR) levels to NNRTI approaching 10% have recently been reported in Mexico. However, subnational differences may exist in PDR prevalence and transmission dynamics. OBJECTIVES: We longitudinally assessed HIV PDR in three geographic areas of Mexico. PATIENTS AND METHODS: HIV-infected, antiretroviral-naive individuals were recruited from 2008 to 2016, from the Central Metropolitan Zone (CMZ), Cancun and Tijuana (1194, 773 and 668 respectively). PDR was estimated using the Stanford HIVdb tool from plasma HIV pol sequences. RESULTS: A higher proportion of females, lower education and lower employment rate were observed in Tijuana, while a higher proportion of MSM was observed in the CMZ (P < 0.0001, all cases). For 2012-16, PDR was 13.4%, 8.9% and 11.2% in the CMZ, Tijuana and Cancun respectively. NNRTI PDR was highest in the three regions (8.7%, 4.8% and 8.1% respectively, P < 0.05); nevertheless, NNRTI PDR in Tijuana was lower than in the CMZ (P = 0.01). For 2008-16, we observed increasing efavirenz resistance trends in all regions (P < 0.05, all cases), reaching 11.8%, 6.1% and 8.3% respectively in 2016. Increasing efavirenz resistance was mostly associated with increasing K103N frequency (P = 0.007 CMZ, P = 0.03 Tijuana, not significant for Cancun). CONCLUSIONS: Our study suggests different NNRTI PDR prevalence and transmission dynamics in three geographical areas of Mexico. Even when increasing trends in efavirenz resistance were observed in the three areas, our observations support that, in a large country such as Mexico, subnational surveillance and locally tailored interventions to address drug resistance may be a reasonable option.

Production of Oxidation-Resistant Cu-Based Nanoparticles by Wire Explosion.

The low performance or high cost of commercially available conductive inks limits the advancement of printed electronics. This article studies the explosion of metal wires in aqueous solutions as a simple, low-cost, and environmentally friendly method to prepare metallic nanoparticles consisting of Cu and Cu alloys for use in affordable, highly conductive inks. Addition of 0.2 M ascorbic acid to an aqueous explosion medium prevented the formation of Cu2O shells around Cu nanoparticles, and allowed for the printing of conductive lines directly from these nanoparticles with no post-treatment. Cu alloy nanoparticles were generated from metal wires that were alloyed as purchased, or from two wires of different metals that were twisted together. Cu nanoparticles alloyed with 1% Sn, 5% Ag, 5% Ni and 30% Ni had electrical conductivities similar to Cu but unlike Cu, remained conductive after 24 hrs at 85 °C and 85% RH.

Synthesis and Purification of Silver Nanowires To Make Conducting Films with a Transmittance of 99%.

Metal nanowire (NW) networks have the highest performance of any solution-coatable alternative to ITO, but there is as yet no published process for producing NW films with optoelectronic performance that exceeds that of ITO. Here, we demonstrate a process for the synthesis and purification of Ag NWs that, when coated from an ink to create a transparent conducting film, exhibit properties that exceed that of ITO. The diameter, and thus optoelectronic performance, of Ag NWs produced by a polyol synthesis can be controlled by adjusting the concentration of bromide. Ag NWs with diameters of 20 nm and aspect ratios up to 2000 were obtained by adding 2.2 mM NaBr to a Ag NW synthesis, but these NWs were contaminated by nanoparticles. Selective precipitation was used to purify the NWs, resulting in a transmittance improvement as large as 4%. At 130.0 Ω sq(-1), the transmittance of the purified Ag NW film was 99.1%.

Broadband behavior of transmission volume holographic optical elements for solar concentration.

A ray tracing algorithm is developed to analyze the energy performance of transmission and phase volume holographic lenses that operate with broadband illumination. The agreement between the experimental data and the theoretical treatment has been tested. The model has been applied to analyze the optimum recording geometry for solar concentration applications.

An outbreak of serogroup C (ST-11) meningococcal disease in Tijuana, Mexico.

BACKGROUND: Invasive meningococcal disease (IMD) has been reported to be endemic in children from Tijuana, Mexico and the risk of an outbreak was always a threat. OBJECTIVES: To describe all clinical, epidemiological and microbiological features of a meningococcal outbreak that occurred in Tijuana, Mexico. METHODS: All cases with IMD were admitted at different emergency departments within the city and diagnosed by culture and agglutination tests. Further restriction fragment length polymorphism pulse field gel electrophoresis (RFLP-PFGE) and multi locus sequence typing (MLST) were performed. All clinical and epidemiological characteristics and interventions were evaluated, as well as risk factors associated with mortality. RESULTS: From 30 January 2013 to 30 March 2013 there were 19 cases of IMD all caused by Neisseria meningitidis serogroup C. The median age was 16 years (2-47), with higher frequency among individuals at least 13 years old (73.7%). At admission, meningitis was the main clinical presentation (94.7%), followed by purpura (78.9%), septic shock (42.1%) and disseminated intravascular coagulation (DIC, 36.8%). Overall mortality was seven (36.8%). Variables associated with higher mortality were, at admission, presence of septic shock, DIC and thrombocytopenia less than 70,000. All 19 cases had no identifiable site or cluster as the source of the outbreak. RFLP-PFGE showed a discriminatory power for only one profile on all N. meningitidis strains analyzed and a clone ST-11 was identified in all strains. Public health interventions were continuous case reporting of all suspected cases of IMD, an increase in active surveillance in all hospitals, training of medical and laboratory personnel, massive and rapid chemoprophylaxis to all close contacts as indicated, and promotion of good health habits. CONCLUSIONS: An outbreak with high mortality of IMD occurred in Tijuana, Mexico. This event and evidence of endemicity should encourage health authorities to evaluate meningococcal vaccination in the region.