Effect of silica on virus infections in mice and mouse tissue culture.
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Silica injections of mice have been reported to kill macrophages, thus allowing herpes simplex virus (HSV) to spread rapidly and leading to an increased severity of HSV infection. Thus, silica presumably could be used to eliminate lactic dehydrogenase virus (LDV) (a model for slow viruses), which is known to multiply exclusively in macrophages. Contrary to expectation, it was found that the LDV titers were increased in silica-injected mice as compared to the titers in control mice. Counts of peritoneal cells at different periods after silica injection showed that silica-induced macrophage damage in vivo resulted in proliferation and migration of macrophages, thus providing additional target cells for LDV replication and leading to high LDV titers. In vitro, silica ingestion also damaged the macrophages, but since no replacement of cells could occur by infiltration, decreased LDV titers were found. Similar findings were obtained with HSV. It is suggested that all persistent viruses multiplying in macrophages will show a similar recrudescence under comparable conditions. (+info)
Abundant expression of EBER1 small nuclear RNA in nasopharyngeal carcinoma. A morphologically distinctive target for detection of Epstein-Barr virus in formalin-fixed paraffin-embedded carcinoma specimens.
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The highly restricted expression of the Epstein-Barr virus (EBV) genome in malignancy has limited the use of EBV detection methods applicable to formalin-fixed paraffin-embedded carcinoma specimens. In EBV-transformed lymphocytes very short nonprotein coding EBV transcripts (EBERs) are expressed in much higher abundance (10(7) copies per cell) than other EBV latency transcripts. Using a 3H riboprobe, the authors demonstrated EBER1 expression in NASOPHARYNGEAL CARCINOMAS (NPCs) as well as in parotid salivary gland. Recognition of EBER1 expression was facilitated by the intensity of hybridization and its characteristic morphology (nuclear with nucleolar sparing). EBER1 expression was not demonstrated in other epithelial malignancies arising from mucosal surfaces (oropharynx, uterine cervix) from which EBV shedding has been detected. Repeat study of the NPC specimens with digoxigenin-labeled probe yielded hybridization signal with subcellular morphologic detail and without background in a 12-hour procedure. Thus the EBER1 transcript is an appropriate target for in situ hybridization detection of EBV in formalin-fixed paraffin-embedded carcinoma specimens. (+info)
Simplified procedures for applying the polymerase chain reaction to routinely fixed paraffin wax sections.
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The polymerase chain reaction was applied to the analysis of DNA contained in archival paraffin wax embedded material. DNA suitable for the reaction was obtained from these tissues by simple extraction methods, without previous dewaxing of tissue sections. When compared with unfixed material, the reaction efficiency was compromised, so that an increased number of amplification cycles were required to produce equivalent amounts of amplified product. This in turn led to an increase in amplification artefacts, which can be minimised by a simple modification of the standard reaction. Amplification of relatively large DNA fragments was not always successful, and it seems prudent to bear this in mind when designing oligonucleotide primers which are to be used for the amplification of archival material. The efficiency of the procedure can be improved by dividing the amplification cycles into two parts: this reduces the amount of reagent needed, is relatively simple and inexpensive, and can be performed in one working day. (+info)
Fire-eater's pneumonia after aspiration of liquid paraffin.
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Fire-eater's pneumonia is a distinct type of chemical pneumonitis that results from aspiration of different types of hydrocarbons. This article describes a case of fire-eater's pneumonia due to accidental aspiration of liquid paraffin. The adolescent patient became febrile the day after the accident. The diagnosis of fire-eater's pneumonia was delayed because aspiration history was not divulged by the patient from the beginning. The most prominent chest X-ray finding was multiple pneumatoceles. He responded well to antibiotics and corticosteroids. Two months after the accident, the lesions had almost completely resolved and only minor scarring was evident. Diagnosis of fire-eater's pneumonia can be difficult, especially if key aspects of related history are not divulged by the patient. Corticosteroid therapy was thought to be beneficial in the rapid recovery of the present case together with broad spectrum antibiotics. (+info)
Three-dimensional architecture of the left ventricular myocardium.
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Concepts for ventricular function tend to assume that the majority of the myocardial cells are aligned with their long axes parallel to the epicardial ventricular surface. We aimed to validate the existence of aggregates of myocardial cells orientated with their long axis intruding obliquely between the ventricular epicardial and endocardial surfaces and to quantitate their amount and angulation. To compensate for the changing angle of the long axis of the myocytes relative to the equatorial plane of the ventricles with varying depths within the ventricular walls, the so-called helical angle, we used pairs of cylindrical knives of different diameters to punch semicircular slices from the left ventricular wall of pigs, the slices extending from the epicardium to the endocardium. The slices were pinned flat, fixed in formaldehyde, embedded in paraffin, sectioned, stained with azan or hematoxilin and eosin, and analyzed by a new semiautomatic procedure. We made use of new techniques in informatics to determine the number and angulation of the aggregates of myocardial cells cut in their long axis. The alignment of the myocytes cut longitudinally varied markedly between the epicardium and the endocardium. Populations of myocytes, arranged in strands, diverge by varying angles from the epicardial surface. When paired knives of decreasing diameter were used to cut the slices, the inclination of the diagonal created by the arrays increases, while the lengths of the array of cells cut axially decreases. The visualization of the size, shape, and alignment of the myocytic arrays at any side of the ventricular wall is determined by the radius of the knives used, the range of helical angles subtended by the alignment of the myocytes throughout the thickness of the wall, and their angulation relative to the epicardial surface. Far from the majority of the ventricular myocytes being aligned at angles more or less tangential to the epicardial lining, we found that three-fifths of the myocardial cells had their long axes diverging at angles between 7.5 and 37.5 degrees from an alignment parallel to the epicardium. This arrangement, with the individual myocytes supported by connective tissue, might control the cyclic rearrangement of the myocardial fibers. This could serve as an important control of both ventricular mural thickening and intracavitary shape. (+info)
Sterile filtered paraffin oil supports in vitro developmental competence in bovine embryos comparable to co-culture.
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PURPOSE: To investigate whether sterile filtered light paraffin oil (SPO) overlaying is superior to washed light mineral oil (WMO) in supporting the in vitro developmental competence of bovine follicular oocytes. In addition, the effects of the two types of oil overlaying were compared with oil overlaying plus co-culture (CC) on bovine embryo development in vitro. METHODS: Bovine follicular oocytes retrieved from abattoir-derived ovary were in vitro matured, fertilized and cultured in 50 microL drops overlayed with WMO or SPO and were subsequently evaluated for development rates. In second experiment, day 2 embryos grown under WMO overlaying were further cultured for 6 days in the presence (WMO+CC and SPO+CC) or absence of adult ear skin fibroblast-based co-culture system overlaid with WMO or SPO. Blastocysts from each group were evaluated for total nuclei number or were further cultured for 48 h to evaluate post-hatching development. RESULTS: SPO overlaying resulted in significant higher (p < 0.05) development rate to morula (44.8% versus 30.6%) and blastocyst (32.8% versus 21.7%) than WMO. Also, treatment of the day 2 embryo cultures with SPO overlaying or oil plus CC (WMO+CC or SPO+CC groups) reached significantly higher development rates from the morula stage compared to embryo cultures treated with the WMO overlaying (p < 0.05). However, the development rates of the SPO treatment group (morula: 72.7%; blastocyst: 53.1%) were slightly high compared to development of the culture treated with WMO+CC (69.6 and 50.4%, respectively). This similar developmental competence pattern was also observed in cell number and embryo hatching rate. CONCLUSION: SPO overlaying is superior to WMO and WMO+CC in supporting in vitro development of bovine embryos. The development rates are further enhanced when embryos are cultured in co-culture system overlaid with SPO. Thus, these data suggest that overlaying oil can significantly influence the pre-implantation embryo development in vitro. (+info)
Growth fraction estimation of malignant lymphomas in formalin-fixed paraffin-embedded tissue using anti-PCNA/Cyclin 19A2. Correlation with Ki-67 labeling.
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The immunohistochemical detection of PCNA/Cyclin, a nuclear protein associated with cell proliferation, represents a potentially useful tool for the study of tumor proliferative activity. Previous studies investigating the reactivity of anti-PCNA/Cyclin monoclonal antibody 19A2 have not clearly defined the population of proliferating cells with which 19A2 reacts in tissue sections. The authors describe a method for detection of PCNA/Cyclin in formalin-fixed, paraffin-embedded tissue using a routine biotin-streptavidin immunohistochemical system that employs an anti-IgM, mu-chain-specific second-stage antibody. The authors used this method to study the proliferative activity of 24 malignant lymphomas, consisting of 12 low-grade lymphomas (LGLs) and 12 intermediate-grade lymphomas (IGLs), and five reactive tonsils. 19A2 data was compared with Ki-67 labeling in frozen sections in the same group of cases. 19A2 provided easily detectable nuclear staining of proliferating cells with reactive cells demonstrating varying intensity of staining, this latter finding most likely due to the varying nuclear concentration of PCNA/Cyclin protein during the cell cycle. In tonsils, 19A2 reacted with germinal center cells and basal keratinocytes. In the malignant lymphomas, there was good correlation between 19A2 and Ki-67 data (r = 0.90, P less than 0.001). The subgroup of LGLs showed a mean PCNA/Cyclin of 26% and a mean Ki-67 of 28%. In the subgroup of IGLs, mean PCNA/Cyclin = 54% and mean Ki-67 = 59%. These results indicate that 19A2 detects a fraction of proliferating cells that is similar to that detected by Ki-67, ie, the growth fraction, and that 19A2 is a reliable marker of proliferative activity in uniformly handled, formalin-fixed, paraffin-embedded tissue. (+info)
Simple, inexpensive, and precise paraffin tissue microarrays constructed with a conventional microcompound table and a drill grinder.
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In 1998, paraffin tissue microarrays (PTMAs) as paraffin blocks containing up to 1,000 cylindrical paraffin tissue core biopsy specimens (PTCBs) for high-throughput molecular profiling of tumor specimens were introduced. PTCBs can be constructed using a manual tissue puncher/arrayer (Beecher Instruments, Sun Prairie, WI; cost, at least $7,000). Furthermore, custom-built PTMAs such as the MaxArray are created by companies such as Zymed Laboratories (South San Francisco, CA; PTMA with 96 holes, about $900). In our search for a less expensive alternative, we constructed PTMAs with up to 558 PTCBs by using a drill grinder, a drill stand, and a microcompound table (Proxxon, Niersdorf, Germany; cost, <$300). (+info)