Non-hazardous organic solvents in the paraffin-embedding technique: a rational approach. Aliphatic monoesters for clearing and dewaxing: butyldecanoate.
Department of Pathology, Hvidovre Hospital, University of Copenhagen, Denmark. Histochemie
(Impact Factor: 3.05).
The aim of this study was to substitute hazardous compounds, used in tissue processing and dewaxing, with compounds having lowest possible toxicity and inflammability without impairing the morphology, staining characteristics, or diagnostic value of the tissue sections. All aromatic compounds and aliphatic hydrocarbons (e.g. alkanes, isoparaffins, petroleum distillates, etc.) were rejected, primarily due to their high vapour pressure. Based on a theoretical study of compounds used for clearing, a number of non-hazardous potential substitutes were chosen. The following experimental study narrowed the group to three unbranched, saturated, aliphatic monoesters containing 12-14 carbon atoms. On large-scale testing of these compounds, we found butyldecanoate to be the closest to an ideal substitute for aromatic and aliphatic hydrocarbons in the histology department: the section quality is at least equal to that obtained with xylene. For dewaxing, it is used at 30-35 degrees C. Butyldecanoate is not suitable as a pre-mounting agent. In practice, this is no problem as modern mounting agents permit mounting of coverslips directly from ethanol without impairing the appearance of the section in the microscope. Butyldecanoate has only a slight odour, insignificant vapour pressure (< 0.01 kPa at 20 degrees C), and does not present a fire hazard (flash point 134 degrees C). The introduction of this compound in the laboratory poses no health hazard, and the substance is biodegradable.
Available from: Vanya Miteva
- "The two-component NEEM drilling fluid is a mixture of Estisol 240 (di-ester of coconut oil extract) and Coasol (blend of di-isobutyl esters of glutamic, succinic, and adipic acids; Lyon et al., 1995; Talalay, 2011). According to the NEEM drilling process description (http://neem.dk/ "
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ABSTRACT: Demonstrating that the detected microbial diversity in non-aseptically drilled deep ice cores is truly indigenous is challenging because of potential contamination with exogenous microbial cells. The NEEM Greenland ice core project provided a first-time opportunity to determine the origin and extent of contamination throughout drilling. We performed multiple parallel cultivation and culture-independent analyses of five decontaminated ice core samples from different depths (100 m to 2051m), the drilling fluid and its components Estisol and Coasol and the drilling chips collected during drilling. We created a collection of diverse bacterial and fungal isolates (84 from the drilling fluid and its components, 45 from decontaminated ice and 66 from drilling chips). Their categorization as contaminants or intrinsic glacial ice microorganisms was based on several criteria, including phylogenetic analyses, genomic fingerprinting, phenotypic characteristics, presence in drilling fluid, chips and/or ice. Firmicutes and fungi comprised the dominant group of contaminants among isolates and cloned rRNA genes. Conversely, most Proteobacteria and Actinobacteria originating from the ice were identified as intrinsic. This study provides a database of potential contaminants useful for future studies of NEEM cores and can contribute towards developing standardized protocols for contamination detection and ensuring the authenticity of the microbial diversity in deep glacial ice. This article is protected by copyright. All rights reserved.
Available from: Ayca Arzu Sayiner
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ABSTRACT: Pathology is a medical speciality essential to patient care. As in classical industry, the conditions of the pathology workers should be optimized, as well as the quality control. This optimization necessitates the knowledge of the hazards and expectations. The major occupational health problems encountered in pathology departments are biological hazards (tuberculosis, hepatitis, HIV, prions), chemical hazards (formaldehyde, xylene, aromatic amins, latex), physical hazards (cut injuries, accidental fires), and ergonomic hazards. Safety in the pathology laboratory is the concern of everyone working in it. Attaining a safe work environment is an inherent element of good quality assurance management. This task is largely a matter of information, education, organization, and common sense. Absolute safety can never be achieved, but by concentrating on basic safe working procedures, one can try to approach this. In order to provide current information that may be used by pathology staff to implement the functional quality and safety of the workplace, hazards and organizational and preventive measures are described. Giriş Klasik endüstride olduğu gibi, patolojide de hasta ile ilgili kalite kontrolü kadar çalışma koşulları da optimize edilmelidir. Yapılan işin kaliteli olmasını beklediğimiz ortamın çalışma şartlarını düşünmek ve iyileştirmek bir zorunluluktur. Bunun için de ihtiyaç ve beklentilerin belirlenmesi gerekir. Patoloji bölümlerinde biyolojik kazalar, kimyasal maddeler, ve fiziki kazalar, ön plandadır. Hem laboratuar çalışanlarının, hem de patoloji asistanı ve uzmanlarının çalışma şartları ve duruş bozuklukları nedeni ile karşılaştıkları fiziksel rahatsızlıklarda mesleki hastalıklarının bir başka yönünü oluşturmaktadır. Patoloji bölümlerinde en fazla karşılaşılan kimyasal maddeler formalin (FA), ksilol (Xy) ve lateksdir. Daha az oranda aromatik aminler ve bazı bölümlerde metakrilat ve gluteraldehid gibi maddelerdir.
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ABSTRACT: We compared the performance of six commercial fixatives proposed to be formalin substitutes with the performance of buffered formalin, Clarke's ethanol-acetic acid, and ethanol, using rat liver, small intestine, and kidney. We investigated the rate of penetration, mode of fixation, extent of protein and structural immobilization, quality of histology and cellular structure following routine dehydration and paraffin embedding, and performance as a fixative for immunohistochemistry. Furthermore, we evaluated the effects of the various fixatives on ultrastructure. Only buffered formalin performed equally well on all tissues tested. While several of the commercial fixatives appeared to preserve liver tissue at 200x, the preservation of kidney, intestinal villi, and smooth muscle was unacceptable. Histological distortion, cell shrinkage and vacuolization were prominent when the substitutes or ethanol were used. In contrast, these artifacts were found occasionally and to a minor degree when buffered formalin or Clarke's fixative were used. Immunohistochemistry demonstrated a total loss of low molecular weight antigens for all fixatives except buffered formalin. The best immunostaining was obtained by combining formalin fixation with antigen retrieval. We conclude that none of the proposed commercial substitutes for buffered formalin are adequate for critical histology or histopathology.
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