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PubMed1976

A paraffin baiting technique that enables a direct microscopic view of "in situ" morphology of Nocardia asteroides with the acid-fast or fluorescence staining procedures.

The paraffin slide culture technique has provided a means of greatly increasing the effectiveness of the paraffin baiting procedure in the identification of Nocardia asteroides. This has been accomplished with paraffin coated slides rather than the conventional paraffin coated rods, which allows for direct microscopic examination of the "in situ" growth because of its flat surface. This microscopic examination is further facilitated by staining with Kinyoun Acid-fast Stain, or combines three important elements necessary for the identification of Nocardia asteroides, namely; "in situ" morphology, acid-fastness and Auramine fluorescence. The conventional paraffin coated rod only shows the ability of Nocardia asteroides to utilize paraffin as a carbon source, and tells nothing about "in situ" morphology, acid-fastness, and fluorescence with Auramine Fluorochrome.

Bacteriological Techniques↗

PubMed1995

Flow cytometric DNA analysis of ulcerative colitis using paraffin-embedded biopsy specimens: comparison with morphology and DNA analysis of fresh samples.

OBJECTIVES: The detection of aneuploidy in colonic mucosa by flow cytometric DNA analysis has been advocated as an indicator of high risk for ulcerative colitis (UC) patients developing colon carcinoma. To date, studies have primarily utilized fresh tissue and have had two limitations: a significant number of possible false-positive findings (aneuploidy in the absence of detectable dysplasia) that may be due to DNA degradation, and the inherent inability to perform retrospective studies. The latter has compromised the adequate assessment of flow cytometric DNA analysis for its clinical utility in UC patients. Our objective was to attempt to overcome the limitations that have been present in DNA analysis by flow cytometry. METHODS: After having established, in our laboratory, an optimal method that allowed reliable DNA analysis on paraffin-embedded mucosal biopsy specimens, we conducted three separate studies to address the above problems associated with DNA analysis with fresh colonic samples: 1) comparison of DNA analysis between fresh and paraffin-embedded colonic mucosal samples from UC patients without dysplasia, 2) correlation between morphology and DNA ploidy on paraffin-embedded tissues showing no dysplasia and various degrees of dysplasia, and 3) sequential analysis of fresh, normal colonic mucosal samples to further evaluate possible causes of false aneuploidy. RESULTS: We observed 1) that there is discordance in DNA ploidy between paraffin-embedded and fresh samples showing no dysplasia in that aneuploidy was found in 33/46 (72%) of fresh samples, whereas 3/40 (7.5%) were aneuploid by biopsies from the corresponding anatomic sites. 2) There is excellent correlation between dysplasia and DNA ploidy results with paraffin-embedded tissue, i.e., none of 16 samples negative for dysplasia, none of seven samples indefinite for dysplasia, and seven of eight samples positive for dysplasia were aneuploid. 3) DNA degradation produced a spurious, near-diploid aneuploid peak in a normal colonic mucosal sample when it was left in saline more than 1 hr before analysis. CONCLUSIONS: The above-described results demonstrate that performing flow cytometric DNA analysis with formalin-fixed paraffin-embedded biopsy samples is feasible and that this technique may provide more reliable ploidy results than does the use of fresh samples, when rapid refrigeration and/or freezing of the fresh samples cannot be accomplished consistently, and will permit retrospective DNA ploidy studies assessing risk of cancer in UC patients.

Adult↗

PubMed1996

[Ki-67 in carcinoma of the breast: from the frozen to the paraffin sections].

We have studied 49 breast cancers in order to evaluate the Ki-67 polyclonal antibody in immunohistochemical assessing of the proliferating cell index on paraffin embedded tissue sections. Polyclonal Ki-67 immunostaining has been compared with monoclonal Ki-67 immunostaining on frozen sections. This study has been performed on two groups of breast cancers: the first using a prospective method including 22 consecutive cases observed in 1994; the second one, in a retrospective analysis of 27 consecutive cases observed in 1987-1988. Frozen section have been shortly fixed with formalin, methanol and acetone and subsequently processed with Ki-67 monoclonal antibody. The paraffin sections, routinely fixed in formalin and embedded in paraffin, have been pretreated in a microwave oven before processing with Ki-67 polyclonal antibody. The proliferating cell index, expressed in a semi-quantitative evaluation as percentage of stained nuclei, resulted differently in the mean and in the median values between the frozen and the paraffin groups. The difference is bigger and significant in the retrospective group observed in 1987-88. On the contrary, the results obtained from frozen and paraffin sections of the prospective group observed in 1994 are comparable. The prospective and the retrospective groups significantly differ in the fixation time. In 1994 the specimens were fixed for no more than 36 hours while previously the fixation time wasn't standardized and often exceeded 36 hours. The Ki-67 polyclonal antibody on paraffin sections is comparable to the Ki-67 monoclonal antibody on frozen sections on condition that fixation is strikingly standardized. The immunostaining with vimentin as antigenicity preservation control is also advisable.

Antibodies, Monoclonal↗

PubMed1995

In situ hybridization for vasopressin mRNA in the human supraoptic and paraventricular nucleus; quantitative aspects of formalin-fixed paraffin-embedded tissue sections as compared to cryostat sections.

In order to study the suitability of formalin-fixed paraffin-embedded brain tissue for vasopressin (AVP)-mRNA detection, we used symmetric halves of 5 human hypothalami. In every case, one half was formalin fixed for 10-35 days and paraffin embedded while the other half was frozen rapidly. Following in situ hybridization (ISH) histochemistry on systematically obtained sections of the supraoptic (SON) and paraventricular nucleus (PVN) of both halves, total amounts of AVP-mRNA in these nuclei were estimated using densitometry of film autoradiographs. Total amounts of radioactivity were found to vary considerably between patients and amounted to 1297 +/- 302 arbitrary units (AU) (PVN) (mean +/- SEM) and 2539 +/- 346 (SON) for the cryostat sections and 868 +/- 94 (PVN) and 1259 +/- 126 (SON) for the paraffin tissue. Variations introduced by the method itself yielded a coefficient of variation of only 0.19. Furthermore, a non-significant negative trend with postmortem delay was found in cryostat tissue, but not in paraffin sections. No effect of fixation time was observed in the paraffin tissue. Both ways of tissue treatment have specific advantages and disadvantages that may be different for other probes or other brain areas. For ISH of a highly abundant mRNA like AVP in a very heterogeneous brain area such as the human hypothalamus, formalin-fixed paraffin-embedded tissue sections can be used for quantitative analysis of entire brain nuclei because of the small variation in this tissue, the remarkably good signal recovery (some 75% as compared to cryostat sections) and its practical advantages with regards to anatomical orientation, storage and sampling of the tissue.

Aged↗

PubMed2006

Toxicoepidemiology in Zimbabwe: admissions resulting from exposure to paraffin (kerosene).

INTRODUCTION: Paraffin (kerosene) ingestion is the most common form of childhood poisoning in most developing countries. Despite this, there is a paucity of toxicoepidemiological data which could potentially be used in measures to reduce preventable exposures. This article reports on the patterns of hospital admissions resulting from paraffin exposure in Zimbabwe. METHODS: All cases of paraffin ingestion admitted to eight major referral hospitals in Zimbabwe from January 1998 to December 1999 (inclusive), were identified using ICD-9 codes and ward registers and relevant information recorded on a standard data collection sheet. RESULTS: There were a total of 327 admissions due to oral exposure to paraffin. This represented 11.8% of all the poisoning admissions to the eight study hospitals. Most exposures (300; 91.7%) occurred accidentally, with only 6.7% resulting from deliberate ingestion of the chemical. The median age on admission was 2 years (interquartile range [IQR] 1-2 yrs) with over 85% of cases in the 0-5 year age range and less than 10% above the age of 12 years. The median age on admission was much higher for deliberate self poisoning (23 yrs; IQR 19-26 yrs) compared to that for accidental poisoning (1.5 yrs; IQR 1-2 yrs). Accidental poisoning from paraffin occurred throughout the year. Over three-quarters of patients received an antibiotic either alone, or in combination with another antibiotic or drug. Paracetamol (24.3%) was the next most commonly encountered treatment. The case fatality rate (CFR) was therefore 0.3 deaths per 100 admissions (95% Confidence Interval 0.0-1.7). CONCLUSION: Paraffin ingestion remains an important cause of poisoning morbidity in Zimbabwe throughout the year, particularly in children. Clinical management appears adequate with a low mortality, although there may be overuse of prophylactic antibiotics. Further study specific to this area is warranted to prevent unnecessary antibiotic use and wastage of resources.

Accidents↗

PubMed1987

Percutaneous and oral absorption of chlorinated paraffins in the rat.

Parallel percutaneous absorption studies of two 14C-labelled chlorinated paraffins (C18, 50-53% chlorination; C28, 47% chlorination) were carried out in the Sprague-Dawley rat. The dermally applied dose (66 mg/cm2) was approximately equivalent to 2.0 g/kg of body weight. An oral absorption study with the C18-chlorinated paraffin (0.5 g/kg) was carried out in rats for comparison. Less than 1% of the dermally applied dose of [1-14C]polychlorooctadecane (50-53% chlorination) and less than 0.1% of the applied dose of [14,15-14C]polychlorooctacosane (47% chlorination) were recovered in excreta, expired air and tissues after 96 hours. In contrast, approximately 86% of the orally administered dose of [1-14C]polychlorooctadecane (0.5 g/kg) was recovered. These results indicate that rat skin acts as an effective barrier to chlorinated paraffins containing eighteen or more carbons and more than 40% chlorine by weight. The oral absorption of the C18 chlorinated paraffin can be estimated to be nearly 100 times greater than its dermal absorption. Based on current toxicity results from rodent experiments and these present findings, chlorinated paraffins of the type tested would be expected to have little or no effect in animals as a result of dermal exposure. It is reasonable to assume that such chlorinated paraffins are unlikely to be systemically toxic to humans by skin contact under normal conditions of production and use.

Administration, Cutaneous↗

PubMed1991

Methods in pathology. Identification of T-cell lymphomas in paraffin-embedded tissues using polyclonal anti-CD3 antibody: comparison with frozen section immunophenotyping and genotypic analysis.

While L26 (CD20) is now well established as a B-cell marker of high specificity for use in paraffin-embedded tissues, paraffin-reactive T-cell antibodies (UCHL1, MT1, Leu-22, DF-T1, and MT2) have not shown comparable lineage specificity. A new commercially available polyclonal antibody directed against a synthetic peptide sequence of the CD3 (T-cell) antigen has recently become available for use on paraffin sections. In order to evaluate the utility of this antibody, we studied CD3 expression in conjunction with L26 and leukocyte common antigen (LCA) in 15 T-cell and 20 B-cell non-Hodgkin's lymphomas (NHL), all genotypically confirmed by DNA hybridization and immunophenotyped by immunoperoxidase studies in frozen tissue. Ten of 15 T-cell NHLs (67%) showed unequivocal immunolabeling of neoplastic cells with anti-CD3 in paraffin-embedded tissue. Of the five negative cases, three were lymphoblastic lymphomas, and two were peripheral (postthymic) lymphomas (one anaplastic large cell, Ki-1 positive and one large cell, immunoblastic). CD3 expression was identical in paraffin and cryostat sections (100% concordance). Twenty of 20 B-cell NHLs were positive with L26 and LCA but were negative with anti-CD3. Other neoplasms examined, including three granulocytic sarcomas and 45 nonhematopoietic tumors, were similarly negative with anti-CD3. We conclude that polyclonal anti-CD3 is a sensitive and highly specific T-cell marker in paraffin-embedded tissue and, when used in conjunction with LCA and L26, that it can determine cell lineage in the majority of non-Hodgkin's lymphomas.

Antigens, CD↗

PubMed1985

Immunohistochemical analysis of human lymphomas with monoclonal antibodies to B cell and Ia antigens reactive in paraffin sections.

Monoclonal antibodies (MoAbs) to B cell- and T cell-specific antigens uniformly have been restricted in their use to cell suspension or frozen section techniques because the antigens that they identify are either masked or lost in the fixation or paraffin-embedding processes. Antiimmunoglobulin antisera, although readily identifying cytoplasmic immunoglobulin in paraffin sections, has not been as useful as originally hoped since the majority of B cell lymphomas express surface immunoglobulins, which requires cell suspensions or frozen sections for detection. Because cell suspension procedures disrupt tissue architecture and frozen section techniques grossly distort morphology, neither method allows the combination of optimal morphologic and immunologic classification of lymphomas. We recently reported two MoAbs, LN-1 and LN-2, that react with B cells in paraffin sections. LN-1 reacts with the surface membrane and cytoplasm of germinal center B cells. LN-2 reacts uniquely with the nuclear membrane and cytoplasm of mantle zone and germinal center B cells and interdigitating histiocytes. We have also identified a new MoAb, LN-3, that reacts with the HLA-DR antigen in paraffin sections. We now report the use of LN-1, LN-2, and LN-3 in the analysis of paraffin sections from 58 non-Hodgkin's lymphomas and 15 cases of Hodgkin's disease. The types of cells reactive with these MoAbs in neoplastic lymphoid proliferations largely recapitulate their benign morphologic and immunologic counterparts. As a panel, LN-1, LN-2, and LN-3 were reactive with 98% of B cell lymphomas, and LN-1 and LN-2 were negative on all T cell lymphomas. In addition to identifying the cell of origin of these malignant proliferations, these MoAbs were also useful for identifying architectural features in neoplastic lymph nodes. Thus, these reagents provide the ability to assess the immunologic phenotype of neoplastic lymphocytes in conjunction with the critical morphologic criteria requiring paraffin embedding.

Antibodies, Monoclonal↗

PubMed1997

Nested polymerase chain reaction-based HLA class II typing for the unique identification of formalin-fixed and paraffin-embedded tissue.

Human leukocyte antigen (HLA) genotyping is routinely performed prior to organ transplantation using peripheral blood leukocyte-derived DNA. In addition, polymerase chain reaction (PCR)-based methods have permitted HLA genotyping using DNA extracted from formalin-fixed and paraffin-embedded tissue, with proven applications in HLA-disease association studies and surgical biopsy identification. The utility of current techniques may be limited by the poor yield of intact DNA from such paraffin biopsies. This paper describes a new nested PCR-based HLA class II genotyping method which reliably detects HLA DRB alleles within DNA extracted from even extremely small paraffin biopsies. This method comprises initial PCR amplification of exon II sequences of the HLA DRB1, 3, 4, and 5 genes using generic PCR primers. Identification of the HLA DRB1 alleles and detection of the DRB3, 4, and 5 genes is then performed using a series of separate individual second-round PCR reactions, each of which contains PCR primer pairs detecting a single HLA DRB allele or group of alleles (PCR-SSP). The ability of this method to detect 19 individual HLA DRB1 alleles or groups of alleles, covering all common DRB1 specificities, was confirmed via concordant results when compared with 'direct' (single amplification step) PCR-SSP analysis of one cell line-derived and nine peripheral blood-derived DNA samples, and with five DNA samples extracted from paraffin biopsies. The technique was then successfully applied to 11 further paraffin biopsy-derived DNA samples, of which ten were untypable by 'direct' PCR-SSP analysis, from five cases in which doubt existed as to the individual origin of the tissues.

Adult↗

PubMed1995

Bivariate cytokeratin/DNA flow cytometric analysis of paraffin-embedded samples from colorectal carcinomas.

Admixture of normal and neoplastic cells is a serious problem in the evaluation of tumor cell kinetic parameters by flow cytometry, in particular for DNA diploid tumors. The admixture of non-neoplastic cells, such as stromal cells and inflammatory cells, can disturb the estimation of the proliferative tumor fraction. This problem has been addressed in fresh tumor samples by applying bivariate flow cytometric analyses for DNA and cytokeratin. We have adapted this approach for formalin-fixed and paraffin-embedded tissue samples of colorectal carcinomas. After preparation of a single cell suspension from paraffin blocks by means of an enzymatic digestion step, the cells of epithelial origin were selectively stained with a panel of subtype specific cytokeratin antibodies. DNA analysis could thus be performed on the cytokeratin-positive cells. The proliferative fractions of the paraffin-embedded samples could be compared with those of the fresh tissue samples and a very good correlation was seen between DNA indices from fresh and paraffin-embedded material. As expected, after gating on the cytokeratin-positive cells an enrichment of the S-phase fraction was seen compared with the ungated cell population. However, this enrichment was more pronounced in the cell suspensions derived from the paraffin-embedded part of the tumor compared with the fresh disaggregated, ethanol-fixed part of the tumor.

Aneuploidy↗

PubMed2003

Paraffin spheres as porogen to fabricate poly(L-lactic acid) scaffolds with improved cytocompatibility for cartilage tissue engineering.

Three-dimensional poly(L-lactic acid) (PLLA) scaffolds with high porosity and pore size ranging from 150 to 700 microm were conveniently prepared with paraffin spheres used as porogen. PLLA/1,4-dioxane solution containing a given amount of paraffin spheres was frozen at -25 degrees C to obtain a solidified mixture, followed with freeze drying and subsequent leaching with hexane to remove the 1,4-dioxane and paraffin spheres, respectively. The fabricated PLLA scaffolds were highly porous with evenly distributed and interconnected pores. The microstructures of the PLLA scaffolds as a function of paraffin-sphere size, paraffin-sphere dosage, and PLLA concentration were characterized by confocal laser scanning microscopy (CLSM) and scanning-electronic microscopy (SEM). To improve the cytocompatibility of the bioinert material, a hybrid PLLA scaffold containing Type I collagen was prepared by pressing the collagen solution into the scaffold under reduced pressure. The amounts of the collagen introduced in the scaffolds were detected by ninhydrin method. The distribution of the collagen in the scaffolds was studied with CLSM. Finally, in vitro cell culture was performed by injecting a chondrocyte suspension into the scaffolds. The results showed that the chondrocytes were more evenly distributed and more spread out in the collagen-modified PLLA scaffolds than in the unmodified ones.

Animals↗

PubMed1990

Flow cytometric DNA content analysis in primary lung cancer: comparison of results from fresh and paraffin-embedded specimens.

Tumor DNA content was determined by flow cytometry in 24 surgically resected specimens from patients with primary lung cancer to compare results from fresh and paraffin-embedded specimens. We found a good correlation in DNA indices between fresh and paraffin-embedded specimens (r = .978), although one tumor with DNA near-diploidy was mistaken as DNA diploid in paraffin-embedded specimens. In the measurements of paraffin-embedded specimens, eight of 24 tumors were DNA multiploid and showed DNA content heterogeneity. These results indicate that DNA content analysis of paraffin-embedded specimens is helpful because it makes it easy to analyze multiple specimens from different parts of the tumor.

Adenocarcinoma↗

PubMed1994

Immunohistochemical detection of tissue factor (TF) on paraffin sections of routinely fixed human tissue.

Tissue factor (TF), a 47 kDa transmembrane glycoprotein, is the essential receptor and cofactor for factor VII/VIIa. Its distribution in normal tissues and in tumours has been recently investigated immunohistochemically with monoclonal and polyclonal anti-TF antibodies in frozen sections. The cardinal problem of this technique is the difficulty of determining exactly the localization of the reaction product at least in certain tissues. Here, we demonstrate a method using monoclonal anti-TF antibodies to detect TF in routinely fixed, microwaved, paraffin-embedded tissues. Generally, there were no fundamental differences in TF distribution in frozen and paraffin-embedded material. However, in most cases, the paraffin sections allow a better cellular localization of TF. For example, the staining pattern for TF in both kinds of sections is identical in kidney, brain and skin. The paraffin-embedded material, however, clearly shows that TF expression is restricted to the parietal and the visceral epithelia of Bowman's capsule of glomeruli in the kidney, and to astrocytes and their processes in the brain. TF reactivity in the skin is revealed to be cell membrane-bound; in cardiomyocytes TF shows an exclusively sarcolemmal localization. The immunohistological detection of TF in paraffin sections is a powerful tool for systematic studies on the possible role of TF in the context of physiological and pathological studies.

Antibodies, Monoclonal↗

PubMed1975

Antidote effect of liquid paraffin in oral solvent intoxication.

The antidote efficacy of liquid paraffin in oral solvent intoxications was investigated in dogs. Groups of 3 to 4 animals each received 1 ml/kg of methylchloroform, 0.3 ml/kg of benzene, or 3 ml/kg of a synthetic gasoline mixture (hexane/heptane/octane, ratio 30:50:20) by gastric intubation. After a prolonged interval the same animals were given 5 ml/kg of liquid paraffin by a separate tube in addition to one of the above solvents. The solvent concentrations in the blood were determined by gas chromatography at appropriate intervals. Administration of liquid paraffin in conjunction with methylchloroform does not significantly affect the absorption process. In the case of benzene and the synthetic gasoline mixture, however, liquid paraffin produces a distinct reduction in the rate of absorption. It is thus concluded that in the therapy of oral solvent-intoxication, liquid paraffin exhibits favorable antidote properties which may however differ from one solvent to the other. In clinically relevant situations involving coadministration of purgatives, the antidote effect must be assessed as being of a higher order than in our animal experiments in which purgatives had to be omitted for external reasons.

Animals↗

PubMed2000

Kinetics of an experimental inflammatory reaction induced by Leishmania major during the implantation of paraffin tablets in mice.

In leishmaniasis, macrophages play important but potentially divergent roles. They act as the host cell in which the parasite may reside and replicate, and, at the same time, they act as an effector cell with the potential to eliminate the parasite. In this work, we experimentally induced an inflammatory model that provokes a continued recruitment of the monocytes to the site of inflammation. This model was carried out by means of implanting paraffin tablets under the skin of Balb/c or C57BL/6 mice. Mice were then infected with Leishmania major to determine how the monocyte inflammatory response to paraffin could influence the course of infection with L. major. Mice were sacrificed 15, 21, 30, and 45 days after infection, and skin and inflammatory capsule were collected for histopathology. At 15 days and 21 days, the lesions induced by L. major in combination with paraffin contained markedly increased numbers of parasites relative to lesions in parallel control animals infected with L. major (without paraffin). Both Balb/c and C57BL/6 mice exhibited high parasite numbers in their lesions. The intense parasite burden observed following paraffin implantation would suggest that the monocytes-macrophages that are recruited to the lesion are acting more as a host cell permitting parasite growth than as an effector cell capable of eliminating L. major. At later times, the two strains of mice stratified according to their genetic susceptibility/resistance profiles. Susceptible Balb/c mice continue to have large parasite burdens, whereas the resistant C56BL/6 mice begin to control parasite numbers. This later observation indicates that the genetic difference between susceptible and resistant strains is not due to differences in monocyte recruitment and cannot be reversed through the altering of monocyte inflammation.

Animals↗

PubMed1982

Effects of dietary paraffin, squalane and sucrose polyester on residue disposition and elimination of hexachlorobenzene in rats.

Previous studies have shown addition of light liquid paraffin to enhance the elimination of organochlorine xenobiotics. In the present study the effect of paraffin on the elimination of [14C]hexachlorobenzene (HCB) was compared with the effect of possible alternative compounds, squalane and sucrose polyester (SPE). Four groups of 7 rats were fed a diet containing 1.5 ppm [14C]HCB for 4 days followed by 10 days on HCB-free diet. Thereafter one group (control) remained on this diet whereas the other 3 groups received a diet supplemented with 8% (w/w) paraffin, squalane or SPE, respectively. Radioactivity in urine and faeces was measured daily and at the end of the experiment in samples of abdominal fat, muscle, liver, kidney and blood. Dietary treatment with either paraffin, squalane or SPE markedly enhanced faecal excretion of [14C]HCB, whereas urinary excretion was not affected. Both the time course as well as the extent of faecal [14C]HCB elimination were similar in the treated groups. After 3 weeks of treatment the amount of [14C]HCB excreted with faeces was about three times higher in treated animals than in controls. The half-life (t1/2) of [14C]HCB elimination from the body was markedly decreased in treated animals (mean 34--38 days) compared to controls (110 days). [14C]HCB concentrations in some major tissues were significantly reduced to the same extent by all three dietary regimens. Thus squalane and SPE are as effective as paraffin in removing HCB from contaminated animals.

Adipose Tissue↗

PubMed1990

Analysis of leukocyte surface antigens on ethanol-fixed paraffin-embedded tissue material.

Ethanol-fixed paraffin-embedded specimens of human tissues were studied whether the surface antigens of leukocytes in these tissues can be stained and analyzed. Three-layer indirect immunoperoxidase staining was performed on the ethanol-fixed paraffin-embedded sections by the use of several monoclonal antibodies for whole human leukocytes (Dako LC), B cells (Dako CD-22, 4KB5, and L26; Leu 14), T cells and their subsets (Dako UCHL-1, T1, T3, T4 and T8; Leu 4, 3a and 2a) and monocyte/macrophage lineage (Dako macrophage, Leu M1, M3 and M5). The results were compared with those on fresh-frozen sections. No essential differences were obtained between the paraffin-embedded and the fresh frozen sections stained by the following antibodies; Dako LC for whole human leukocytes; Dako UCHL-1, T3 and Leu 4 for T cells; Dako CD22, 4KB5, L26 and Leu 14 for B cells; Dako macrophage, Leu M1 and M5 for monocyte/macrophage lineage. On the other hand, the subsets of T cells could only be detected on the fresh-frozen sections. The results of the leukocyte analysis on the paraffin-embedded specimens of several renal diseases were very similar to those reported by other investigators on fresh-frozen sections or PLP-fixed materials. Thus, by the use of appropriate monoclonal antibodies, the ethanol-fixed paraffin-embedded material can be used for leukocyte analysis except for the definition of T cell subsets.

Antibodies, Monoclonal↗

PubMed1992

Detection of hepatitis C viral RNA sequences in fresh and paraffin-embedded liver biopsy specimens of non-A, non-B hepatitis patients.

In this study methods of HCV-RNA detection in fresh frozen and formalin-fixed, paraffin-embedded liver biopsies are described. Of 22 untreated chronic non-A, non-B hepatitis patients and 6 control patients, a plasma sample and part of a liver biopsy were freshly frozen for hepatitis C virus (HCV) cDNA-PCR. From 16 of the same non-A, non-B hepatitis patients and from 5 of the same control patients formalin-fixed, paraffin-embedded liver tissue from the same biopsy was available also for HCV cDNA-PCR. In 13 of 22 non-A, non-B hepatitis patients HCV-RNA could be detected in plasma as well as in liver tissue. In the other 9 non-A, non-B hepatitis patients and in 6 control patients, no HCV-RNA was detectable in either plasma or liver tissue. The comparison between HCV cDNA-PCR results in fresh frozen versus formalin-fixed, paraffin-embedded liver biopsies showed that although detection of HCV-RNA in both correlated 100% the quantity of HCV-RNA was lower in the formalin-fixed, paraffin-embedded liver biopsies of 5 of 8 patients for whom end-point dilution titration of liver RNA was performed. We conclude that using the procedures described HCV-RNA can be reliably detected in both fresh-frozen and formalin-fixed, paraffin-embedded liver biopsies and that HCV cDNA-PCR in liver tissue may become an important assay, especially for monitoring anti-viral therapy.

Biopsy↗