DNA Packaging and Polycation Length Determine DNA Susceptibility to Free Radical Damage in Condensed DNA.

In nature, DNA exists primarily in a highly compacted form. The compaction of DNA in vivo is mediated by cationic proteins: histones in somatic nuclei and protamines in sperm chromatin. The extreme, nearly crystalline packaging of DNA by protamines in spermatozoa is thought to be essential for both efficient genetic delivery as well as DNA protection against damage by mutagens and oxidative species. The protective role of protamines is required in sperm, as they are sensitive to ROS damage due to the progressive loss of DNA repair mechanisms during maturation. The degree to which DNA packaging directly relates to DNA protection in the condensed state, however, is poorly understood. Here, we utilized different polycation condensing agents to achieve varying DNA packaging densities and quantify DNA damage by free radical oxidation within the condensates. Although we see that tighter DNA packaging generally leads to better protection, the length of the polycation also plays a significant role. Molecular dynamics simulations suggest that longer polyarginine chains offer increased protection by occupying more space on the DNA surface and forming more stable interactions. Taken together, our results suggest a complex interplay among polycation properties, DNA packaging density, and DNA protection against free radical damage within condensed states.

Effect of Extraction Procedure Substitution on Automated Tacrolimus, Sirolimus, and Cyclosporine Assays.

BACKGROUND: An erroneously high tacrolimus level was reported to a clinician. A root cause analysis investigation failed to determine the cause of the error. It was suspected that the incorrect preanalytical extraction reagent and procedure was used during testing; however, how this would affect the assayed drug concentration was unclear. Here we investigated the effect of the substitution of sirolimus, tacrolimus, and cyclosporine extraction reagents on assayed drug concentration. METHODS: Tacrolimus, sirolimus, and cyclosporine concentration were measured on the Abbott Architect i2000 analyzer. Each assay requires a preanalytical extraction step, with a distinct reagent. We investigated the effect of the substitution of the extraction reagents and procedure between the 3 assays on the measured drug concentration. Two experiments were performed, one on samples of known drug concentration and one on samples with no drug present. RESULTS: Substituting cyclosporine and sirolimus extraction procedures increased assayed tacrolimus concentrations from 5.6 to 8.47 (+51.25%) and 8.13 (+45.18%) ng/mL, respectively. Extraction procedure substitutions decreased assayed sirolimus from 13.63 to 4.60 (-66.25%) and 8.07 (-40.79%) ng/mL for cyclosporine and tacrolimus. Cyclosporine concentration increased from 274.60 to 391.30 (+42.50%) ng/mL using sirolimus extraction reagents and to 757.30 (+175.78%) ng/mL using tacrolimus extraction reagents. Cross-reactivity was observed between the tacrolimus assay and sirolimus and cyclosporine extraction reagents. CONCLUSIONS: Significant changes, both positive and negative, are observed in assayed drug concentration when incorrect extraction procedures are used in the Abbott i2000 tacrolimus, sirolimus, and cyclosporine assays. Preanalytic extraction procedures should be investigated when performing root cause analysis for erroneous therapeutic drug values.

Analytical assessment and validation of the ProteinSimple ELLA serum B-cell maturation antigen assay.

Objectives: Soluble B-Cell Maturation Antigen (sBCMA) is a degradation product of plasma cell-bound BCMA found in serum. Serum sBCMA concentrations correlate with bone marrow plasma cellularity, making it an attractive biomarker for monitoring plasma cell disorders, such as multiple myeloma. Here we evaluated the automated BCMA immunoassay for the ProteinSimple ELLA, for the analysis of sBCMA. Design & methods: Inter and intra-run precision was assessed through replicate sBCMA measurements at 3 different concentration levels. Linearity was determined through serial dilution of a high sBMCA patient sample. Accuracy was assessed through split specimen analysis on two separate lots of reagents. Stability was assessed at 3 temperature levels over 14 days. Cross-reactivity was assessed on BCMA targeting and non-targeting chemotherapeutics. A reference range was established through the analysis of 146 healthy donor samples. The effect of endogenous interferents was assessed through spiking and recovery studies. Results: Inter and intra-run precision studies afforded CVs of <10% at all three concentration levels. Analytical measurement range was confirmed from 0.1 to 7 ng/mL. Accuracy studies afforded a slope of 0.976, intercept of 1.22, R2 of 0.996. Assayed sBCMA values were unaffected by endogenous interferents and non-BMCA targeting antibodies. BCMA targeting therapeutics negatively affected assayed sBCMA concentrations. The reference range was established at 19-58 ng/mL sBCMA is analytically stable. Conclusions: The ProteinSimple ELLA sBCMA assay shows acceptable performance for the clinical assessment of sBCMA. The assay was highly affected by BCMA targeting therapeutics, thereby patients undergoing this therapy should not have their sBCMA levels assessed by this method.

Comparison of a Novel Thin-Walled 25-gauge Needle Push Button Blood Collection Set to a Standard 23-gauge Needle in a Cancer Patient Population.

BACKGROUND: Phlebotomy can be an uncomfortable and even painful experience that increases in likelihood in patients who require frequent blood draws, such as those with cancer. The 25-gauge BD Vacutainer® UltraTouch™ Push Button Blood Collection Set has a smaller outer bore needle size and unique bevel configuration, which in theory should reduce pain associated with phlebotomy. Smaller needles typically cause less pain, however, they have a higher incidence of compromising the specimen integrity. Innovative engineering allows this particular needle to maintain a larger inner bore size similar to a standard 23-gauge needle. This study compares pain and specimen integrity between this novel device and a standard 23-gauge needle. METHODS: Two cohorts of 190 patients each had phlebotomy performed with either needle. Pain experienced was assessed by patient surveys, rating pain from 0 (low) to 10 (high). Sample integrity was assessed by determining the hemolysis index (Abbott Architect c8000). RESULTS: No statistically significant difference in median pain scores was observed between the 2 cohorts, P-value: 0.068. The 23-gauge cohort more frequently reported 3+ pain than the 25-gauge cohort, 14/190 vs 5/190. Pain scoring 1 and 2 was more frequent in the 25-gauge cohort, 84/190 vs 54/190. Pain scores of 0 were more frequent in the 23-gauge cohort, 122/190 vs 101/190. This stratification is statistically significant, P-value: 0.003. The 25-gauge needle showed no increase in hemolysis rates, P-value: 0.5. CONCLUSIONS: Sample integrity was identical between both needles. The 25-gauge needle resulted in less 3+ pain, while pain scoring 1 and 2 was more frequent in the 25-gauge cohort.

Use of a Daratumumab-Specific Immunofixation Assay to Assess Possible Immunotherapy Interference at a Major Cancer Center: Our Experience and Recommendations.

BACKGROUND: The incorporation of monoclonal antibodies, such as daratumumab, into multiple myeloma treatment regimens has led to the issue of false-positive interference in both serum protein electrophoresis (SPEP) and immunofixation (IF). The Hydrashift assay removes daratumumab interference from IF, allowing for correct interpretation. Here, we retrospectively examined the use of the Hydrashift assay at a large cancer center and provide guidelines on its most appropriate use. METHODS: 38 patients with distinct daratumumab peaks on their SPEP were selected and were used to quantify the daratumumab peak on SPEP using the Sebia Phoresis software. A retrospective review of all Hydrashift assays ordered at our institution from July 2018 to March 2020 was performed. Data collected included patient clone type, IF migration patterns, and Hydrashift result. Serial quantification of SPEP results was performed as the corresponding IF transitioned from a true positive to a false positive. RESULTS: Daratumumab adds a maximum magnitude of 0.20 g/dL on SPEP. Serial SPEP quantification showed IF transitioned from true positive to false positive when M-spikes ranged from 0.09 g/dL to 0.11 g/dL. Over 20 months, our laboratory performed 280 Hydrashift assays on 96 patients, 43/96 of whom had comigrating daratumumab/IgG-K IF bands. CONCLUSIONS: The Hydrashift assay is typically unnecessary in patients with large M-spikes, >0.25 g/dL, regardless of clone type. When patient history is available, we recommend the Hydrashift assay be used in patients with comigrating daratumumab/IgG-K bands with M-spikes of <0.25 g/dL.

Características morfológicas angiográficas de aneurismas de artéria cerebral media: classificação e efeitos sobre os riscos de ruptura / Angiographic morphological characteristics of middle cerebral Artery aneurysms: classification and effects on the risk of rupture

O tratamento de aneurismas de arteria cerebral media (AACM) e a relação de sua morfologia com a probabilidade de rupturasão tópicos importantes na neurocirurgia vascular. Objetivo: Avaliar a correlação entre a morfologia desses aneurismas e 1)probabilidade de ruptura do aneurisma e 2) sua mobimortalidade. Métodos: Vinte e nove pacientes portadores de AACM nosegmento M1 (4 pacientes com aneurismas múltiplos) foram acompanhados / tratados por nossa equipe em uma única instituiçãopelos últimos 5 anos. Catorze aneurismas sofreram ruptura no momento da admissão e 15 foram diagnosticados acidentalmente.Através do formato e geometria, os aneurismas foram classificados e correlacionados com a taxa de ruptura e morbimortalidade.Resultados: Os aneurismas apresentaram medidas entre 7 e 10 mm de diâmetro (90%), sem diferença no tamanho entre os rotos enão-rotos. Pacientes cujos AACMs se romperam na admissão eram o triplo daqueles não-rotos com formato elíptico transverso ede pera invertida (21% vs 9%, p<0,05). Por outro lado, pacientes com AACMs não-rotos possuem aneurisma em formato de pera(36,3% vx 5,2%, p<0,001). Aneurismas com formato arredondado eram os mais frequentes, embora não fosse significativamentepropensos à ruptura. Conclusão: Embora a amostra seja pequena, concluímos que aneurismas com formato elíptico transversoe de pera invertida estavam mais associados com a ruptura que aqueles redondos ou em forma de pera.

Casuística e follow up de 1.639 casos de síndrome do túnel do carpo operados por técnica aberta protocolada no serviço: comparação dos nossos resultados com os obtidos por outras técnicas segundo a literatura / Case series and follow-up of 1.639 cases of carpal tunnel syndrome operated on by open technique. Comparision of our results with those obtained by other techniques according to literature

A síndrome do túnel do carpo é uma afecção muito frequente , acometendo até 10% da população mundial ao longo da vida e corresponde a aproximadamente 90% de todas as neuropatias periféricas compressivas. Como fatores de risco, alem do sexo feminino e as idades referidas, também são relatados na literatura o tabagismo, a obesidade, o uso de anticoncepcionais orais, de terapias para emagrecer, os transtornos digestivos e principalmente doenças concomitantes como a artrite reumatóide, a acromegalia, gota, tuberculose, insuficiência renal, hipotireoidismo, amiloidose e diabetes mellitus. Objetivo: Comparar a experiência de 1639 pacientes operados com técnica aberta em nosso serviço, com os resultados obtidos por outras técnicas cirúrgicas consagradas pela literatura mundial. Material e Métodos: Apresentamos 1639 casos de Síndrome do Túnel do carpo, todos conduzidos segundo mesmo protocolo: diagnóstico clínico associado a eletrofisiológico, tratamento cirúrgico em pacientes com quadro moderado a severo sem resposta ao tratamento clínico ou piora neurológica, sempre através da técnica aberta protocolada no serviço, com seguimento ambulatorial pós-cirúrgico quinzenal e posteriormente mensal por 6 a 12 meses. Resultados: Os resultados obtidos mostraram que 1490 pacientes (90,9%) apresentaram melhora imediata e significativa do quadro. Não houve nenhum caso de lesão cirúrgica do nervo mediano e nenhum dos pacientes apresentou déficit motor sequelar. Os resultados cirúrgicos diferiram da literatura, principalmente se comparados a resultados relatados por serviços que realizam técnicas cirúrgicas por vias endoscópicas. Conclusão: A técnica usada em nossos casos demonstra baixa incidência de complicações, comparada com outros métodos descritos na literatura, que apresentam complicações maiores, curva de aprendizado mais longa e ao nosso ver, o fato de os poucos casos bons publicados voltarem mais cedo ao trabalho, não justifica seu uso pela gravidade das complicações.

Surgical management of brainstem cavernous malformations.

Bleeding from brainstem cavernomas may cause severe deficits due to the absence of non-eloquent nervous tissue and the presence of several ascending and descending white matter tracts and nerve nuclei. Surgical removal of these lesions presents a challenge to the most surgeons. The authors present their experience with the surgical treatment of 43 patients with brainstem cavernomas. Important aspects of microsurgical anatomy are reviewed. The surgical management, with special focus on new intraoperative technologies as well as controversies on indications and timing of surgery are presented. According to several published studies the outcome of brainstem cavernomas treated conservatively is poor. In our experience, surgical resection remains the treatment of choice if there was previous hemorrhage and the lesion reaches the surface of brainstem. These procedures should be performed by experienced neurosurgeons in referral centers employing all the currently available technology.

Tuberculose vertebral: experiência de 23 casos com follow-up de 6 anos / Potts disease: experience with 23 cases with 6 years of follow-up

Objetivos: A tuberculose vertebral ou Mal de Pott é uma forma da tuberculose extrapulmonar, onde ocorre o comprometimento da coluna vertebral em até 50% dos casos de comprometimento ósseo. Temos como objetivo demonstrar a importância desta afecção em nosso meio e compartilhar a experiência de nosso serviço no tratamento da enfermidade.Métodos: Foram coletadas informações sobre os casos de tuberculose vertebral diagnosticados e tratados em nosso serviço,totalizando 23 pacientes em 30 anos, durante os quais foram acompanhados evolutivamente neste período, com follow up de até 6 anos. Observamos queixas iniciais, presença de déficit motor e de dor radicular; submetemos todos os pacientes a tratamento cirúrgico individualizado, sendo introduzido esquema tríplice, com avaliação da evolução dos pacientes. Resultados: Obtivemos melhora em 8 dos 9pacientes com déficit neurológico, sendo que 6 (75%) pacientes obtiveram recuperação de 1 ou mais pontos na escala de força e 2 (25%) retornaram para força grau V. Conclusão: A tuberculose vertebral é uma afecção deformante com grande potencial de déficit neurológico, cujo diagnóstico é realizado com base em dados clínicos, reforçados pelos resultados de exames de imagem, e confirmados pelo resultado de anátomo-patológico e cultura. Normalmente, ocorre uma ótima resposta a descompressão do canal medular e ao uso de antibióticos do esquema tríplice.

Abscessos do tronco cerebral: apresentação de seis casos / Brain stem abscess: a study of six cases

Estudo retrospectivo de seis casos de abscesso de tronco cerebral, atendidos num período de cinco anos em nosso Serviço. Foram levados em consideração: idade dos pacientes, sexo, comorbidades, sorologia para HIV, quadro clínico, tratamento realizado (craniotomia ou punção por estereotaxia), microorganismo identificado e resultado do tratamento. Apresentamos, a seguir, a discussão dos casos e revisão da literatura...