Detection of gene expression in mouse embryos and tissue sections

Analysis of gene expression patterns is central to the study of embryonic development. This chapter details methods for detecting gene expression in whole mouse embryos and in tissue sections. The most commonly used methods available in mouse are described and include mRNA in situ hybridization, immunohistochemistry, and detection of enzymatic and fluorescent protein reporters.

The role of frozen section in surgical staging of low risk endometrial cancer

BACKGROUND

The role of frozen section (FS) in intraoperative decision making for surgical staging of endometrial cancer is controversial. Objective of this study is to assess the agreement rate between the FS and paraffin section (PS); and the potential impact of the role of FS in the intra-operative decision making for the complete surgical staging in low risk endometrial cancer.

METHODS

This is a retrospective analysis of patients diagnosed with intra-operative FS stage I, grade I or II endometrial cancer from 1995-2004. FS results were compared with final pathology results with regard to tumor grade, depth of myometrial invasion, cervical involvement, lymphovascular invasion, and lymph node involvement. Agreement statistic with kappa was calculated using SPSS statistical software. Categorical variables were tested using chi-square test with p value of ≤0.05 being statistically significant.

RESULTS

Of the 457 patients with endometrial cancer, 146 were evaluated by intra-operative FS and met inclusion criteria. FS results were in disagreement with permanent section in 35% for the grade (kappa 0.58, p = 0.003), 28% for depth of myometrial invasion (kappa 0.61, p<0.0001), 13% for cervical involvement (kappa 0.78, p = 0.002), and 32% for lymphovascular invasion (kappa 0.6, p = 0.01). Permanent pathology upstaged 31.9% & 23.2% of FS stage IA, & IB specimen respectively. Lymph node dissection was done in 56.8%. Lymph node metastasis was identified in 8.4%. Use of intraoperative FS would have resulted in suboptimal surgical treatment in 13% stage IA and 6.6% of stage IB patients respectively by foregoing lymphadenectomy.

CONCLUSION

A significant number of patients with low risk endometrial cancer by FS were upstaged and upgraded on final pathology. Before placing absolute reliance on intraoperative FS to undertake complete surgical staging, the inherent limitation of the same in predicting final stage and grade highlighted by our data need to be carefully considered.

[Resistance of the petroleum-oxidizing microorganism Dietzia sp. to hyperosmotic shock in reconstituted biofilms]

A number of halotolerant and halophilic bacterial strains were isolated from the Romashkinskoe oil field (Tatarstan) stratal waters having a salinity of up to 100 g/l. The isolation of pure cultures involved biofilm reconstitution on M9 medium with paraffins. The associations obtained were dispersed and reinoculated onto solid media that contained either peptone and yeast extract (PY) or paraffins. It was shown that such associations included both oil-oxidizing bacteria and accompanying chemoheterotrophic bacteria incapable of oil oxidation. The pure cultures that were isolated were used for creating binary biofilms. In these biofilms, interactions between halophilic and nonhalophilic bacteria under hypo- and hyperosmotic shocks were investigated. We conducted a detailed study of a biofilm obtained from an oil-oxidizing halotolerant species (with an upper growth limit of 10-12% NaCl) identified as Dietzia sp. and an extremely halophilic gram-negative bacterium (growing within the 5-20% NaCl concentration range) of the genus Chromohalobacter that did not oxidize paraffins. If these microorganisms were grown in a mixed suspension (planktonic) culture that was not supplemented with an additional amount of NaCl, no viable cells of the halophilic microorganism were detected after reinoculation. In contrast, only halophilic cells were detected at a NaCl concentration of 15%. Thus, no mutual protective influence of the microorganisms manifested itself in suspension culture, either under hypo- or under hyperosmotic shock. Neither could the halophile cells be detected after reinoculating a biofilm obtained on a peptone medium without addition of NaCl. However, biofilms produced at a NaCl concentration of 15% contained approximately equal numbers of cells of the halophilic and halotolerant organisms. Thus, the halophile in biofilms sustaining a hyperosmotic shock exerts a protective influence on the halotolerant microorganism. Preliminary data suggest that this effect is due to release by the halophile of osmoprotective substances (ectoine and glutamate), which are taken up by the halotolerant species. Such substances are diluted by a large medium volume in suspension cultures, whereas, in biofilms, their diffusion into the medium is apparently hampered by their interaction with the intercellular polymer matrix.

Bioaccumulation and trophic magnification of short- and medium-chain chlorinated paraffins in food webs from Lake Ontario and Lake Michigan

Chlorinated paraffins (CPs) are complex mixtures of chlorinated alkanes used in a myriad of industrial applications as flame retardant plasticizers and additives. In this study, the distribution and bioaccumulation/biomagnification of short-chain CPs (C10-C13, SCCPs) and medium-chain CPs (C14-C17, MCCPs) were investigated in samples collected between 1999 and 2004 from Lake Ontario and northern Lake Michigan. Total (sigma) SCCPs and sigmaMCCPs concentrations in water from Lake Ontario were 1190 pg/L and 0.9 pg/L (data from 2004 only), respectively. CPs were also detected in invertebrates and fish from both lakes. SCCP predominated in organisms from Lake Michigan with the highest mean concentrations found in lake trout [Salvelinus namaycush, 123 +/- 35 ng/g wet weight (ww)]. In Lake Ontario, MCCPs predominated in most species with the highest levels detected in slimy sculpin (Cottus cognatus, 108 ng/g ww) and rainbow smelt (Osmerus mordax, 109 ng/g ww). Bioaccumulation and biomagnification of CPs was evaluated on an isomer basis (i.e., C10H17Cl5, C10H16Cl6, etc). Log bioaccumulation factors for lake trout (lipid based) ranged from 4.1 to 7.0 for SCCPs and 6.3 to 6.8 for MCCPs. SCCPs and MCCPs were found to biomagnify between prey and predators from both lakes with highest values observed for Diporeia-sculpin (Lake Ontario, C15Cl9 = 43; Lake Michigan, C10Cl5 = 26). Trophic magnification factors for the invertebrates-forage fish-lake trout food webs ranged from 0.41 to 2.4 for SCCPs and from 0.06 to 0.36 for MCCPs. Given the prominence of CPs, particularly in lake waters and in lower food web organisms, further investigation is needed to evaluate the magnitude of their distribution and accumulation/magnification in the Great Lakes environment.

Isolation and characterization of a potential paraffin-wax degrading thermophilic bacterial strain Geobacillus kaustophilus TERI NSM for application in oil wells with paraffin deposition problems

Paraffin deposition problems, that have plagued the oil industry, are currently remediated by mechanical and chemical means. However, since these methods are problematic, a microbiological approach has been considered. The bacteria, required for the mitigation of paraffin deposition problems, should be able to survive the high temperatures of oil wells and degrade the paraffins under low oxygen and nutrient conditions while sparing the low carbon chain paraffins. In this study, a thermophilic paraffinic wax degrading bacterial strain was isolated from a soil sample contaminated with paraffinic crude oil. The selected strain, Geobacillus TERI NSM, could degrade 600mg of paraffinic wax as the sole carbon source in 1000ml minimal salts medium in 7d at 55 degrees C. This strain was identified as Geobacillus kaustophilus by fatty acid methyl esters analysis and 16S rRNA full gene sequencing. G. kaustophilus TERI NSM showed 97% degradation of eicosane, 85% degradation of pentacosane and 77% degradation of triacontane in 10d when used as the carbon source. The strain TERI NSM could also degrade the paraffins of crude oil collected from oil wells that had a history of paraffin deposition problems.

[Bioremediation of oil-polluted soil with an association including the fungus Pleurotus ostreatus and soil microflora]

The possibility of application of the Pleurotus ostreatus D1-soil microflora to bioremediation of oil-polluted soils was studied. The fungus degraded mainly the aromatic fraction, whereas soil microflora intensely degraded paraffin and naphthene oil fractions. Introduction of the fungus Pleurotus ostreatus D to soil induces degradation of a wider range of oil hydrocarbons. It is reasonable to further investigate the discovered phenomenon in order to improve procedures of remediation of oil-polluted soils.

Human papillomavirus 16 E5 oncogene contributes to two stages of skin carcinogenesis

High-risk human papillomaviruses (HPVs), which cause the vast majority of cervical cancer, other anogenital cancers, and a subset of head and neck squamous cell carcinomas, encode three oncogenes: E5, E6, and E7. To determine the oncogenic properties of HPV16 E5 in vivo, we previously generated K14E5 transgenic mice, in which expression of E5 was directed to the basal compartment of stratified squamous epithelia. In these mice, E5 induced epidermal hyperplasia and spontaneous skin tumors. In the current study, we determined how E5 contributes to tumor formation in the skin using a multistage model for skin carcinogenesis that specifies the role of genes in three stages: initiation, promotion, and malignant progression. Both initiation and promotion are required steps for papilloma formation. K14E5 mice treated with the initiating agent 7,12-dimethylbenz(a)anthracene (DMBA) developed more papillomas than like-treated nontransgenic mice, whereas neither K14E5 nor nontransgenic mice treated with the promoting agent 12-O-tetradecanoylphorbol-13-acetate (TPA) developed papillomas. K14E5 mice treated with both DMBA and TPA to induce large numbers of papillomas had a higher incidence and earlier onset of carcinoma progression compared with like-treated nontransgenic mice. Thus, HPV16 E5 contributes to two stages of skin carcinogenesis: promotion and progression. The progressive neoplastic disease in K14E5 mice differed from that in nontransgenic mice in that benign tumors converted from exophytic to endophytic papillomas before progressing to carcinomas. Initial genetic and immunohistopathologic analyses did not determine the underlying basis for this distinct morphology, which correlates with a highly penetrant neoplastic phenotype.

Paraffin baiting system for demonstration of growth and biofilm production in Pseudomonas aeruginosa

Pseudomonas aeruginosa is one of the commonest pathogens among the pseudomonads. This organism can grow in minimal nutritional requirements. Because of the ability of pseudomonads to grow on paraffin is not commonly found among other human pathogens and the primary human pathogen being P. aeruginosa, we studied the adaptation of this organism to paraffin baiting system for growth and biofilm formation. Strains were tested for the capacity to use paraffin as the sole source of carbon using Czapek's minimal salt medium. Of the 53 clinical isolates of P. aeruginosa, 20 strains exhibited growth by 24 hrs and 42 strains by 48 hrs. The remaining strains did not show any growth in the paraffin baiting system. The oxidase test with the paraffin baiting system was also performed. This simple and inexpensive method can be used to isolate and demonstrate the biochemical and biofilm forming capacity of the organism.

Solid state "self-calibrated" EPR-dosimeters-advantageous and shortcomings

EPR dosimetry method with alpha-alanine as radiation sensitive material (RSM) is widely used in high dose dosimetry laboratories. However, it is not suitable for routine industrial applications mainly because of difficult EPR measurement procedure. In order to simplify quantitative EPR dosimetry measurements Yordanov and Gancheva developed so-called "self-calibrated" (sc) dosimeters consists of RSM (alpha-alanine, sugar, other ones), Mn2+/MgO as internal EPR intensity standard (IES) and a binder. The aim of this work was to check dosimetric properties of two experimental batches of sc EPR dosimeters with alpha-alanine and sugar as RSM, Mn2+/MgO as IES and paraffin as a binder. The percentage content of the components was 60, 5 and 35% (w/w), respectively. It was established that the investigated alanine sc-dosimeters are about two times more sensitive than the sugar ones. The dose-response coefficient, K(dr) of sc-alanine dosimeters was stable in all investigated dose range from 1 to 23 kGy. The K(dr)-value of sugar sc-dosimeters decreased with the dose what was in a contradiction to the results pointed to the high stability of radiation generated sugar radicals. The observed effect arose probably from the special chemical procedure used for the sc-sugar dosimeters production. The results confirmed an expectation that the position of sc dosimeter in the cavity is not important factor for accurate dose evaluation. It allows to read-out dosimetric signals in shorter time, with lower uncertainty and on less sophisticate EPR-spectrometers than that commonly used till now. The main shortcomings of sc dosimeters are: (a) the limitation of RSM suitable for sc dosimeters to these ones having strictly linear signal to dose characteristic; (b) necessity to assure very good homogeneity of dosimeter material; and (c) the cost of IES present in the amount of some percent in each sc dosimeter.

Utilization of n-alkanes by a newly isolated strain of Acinetobacter venetianus: the role of two AlkB-type alkane hydroxylases

A bacterial strain capable of utilizing n-alkanes with chain lengths ranging from decane (C10H22) to tetracontane (C40H82) as a sole carbon source was isolated using a system for screening microorganisms able to grow on paraffin (mixed long-chain n-alkanes). The isolate, identified according to its 16S rRNA sequence as Acinetobacter venetianus, was designated A. venetianus 6A2. Two DNA fragments encoding parts of AlkB-type alkane hydroxylase homologues, designated alkMa and alkMb, were polymerase chain reaction-amplified from the genome of A. venetianus 6A2. To study the roles of these two alkM paralogues in n-alkane utilization in A. venetianus 6A2, we constructed alkMa, alkMb, and alkMa/alkMb disruption mutants. Studies on the growth patterns of the disruption mutants using n-alkanes with different chain lengths as sole carbon source demonstrated central roles for the alkMa and alkMb genes in utilization of C10 to C18 n-alkanes. Comparative analysis of these patterns also suggested different substrate preferences for AlkMa and AlkMb in n-alkane utilization. Because both single and double mutants were able to grow on n-alkanes with chain lengths of C20 and longer, we concluded that yet another enzyme(s) for the utilization of these n-alkanes must exist in A. venetianus 6A2.

[The properties of hydrocarbon-oxidizing bacteria isolated from the oilfields of Tatarstan, Western Siberia, and Vietnam]

Eleven strains of hydrocarbon-oxidizing bacteria, isolated from oilfields, representing the genera Rhodococcus, Gordonia, Dietzia, and Pseudomonas, were characterized as mesophiles and neutrophiles. Rhodococci were halotolerant microorganisms growing in a media containing up to 15% NaCl. All the strains oxidized n-alkanes of crude oil. An influence of the cultivation temperatures (28 or 45 degrees C) and organic supplements on the degradation of C12-C30 n-alkanes in oxidized oil by two bacterial strains of the genus Pseudomonas was shown. The introduction of acetate, propionate, butyrate, ethanol, and sucrose led mainly to the decreased oxidation of petroleum paraffins. At certain cultivation temperatures, the addition of volatile fatty acid salts increased the content of individual n-alkanes in oxidized vs. crude oil.

Anti-human Olig2 antibody as a useful immunohistochemical marker of normal oligodendrocytes and gliomas

Olig2 is a recently identified transcription factor involved in the phenotype definition of cells in the oligodendroglial lineage. The expression of Olig2 transcript has been demonstrated in human oligodendroglial tumors, although the protein expression has not been studied extensively. We developed a polyclonal antibody to human Olig2 and analyzed it immunohistochemically. The antibody depicted a single distinct band of predicted molecular weight by Western blotting, and did not cross-react with human Olig1. In normal human brain tissue, the nuclei of oligodendrocytes of interfascicular, perivascular, and perineuronal disposition were clearly labeled by the antibody. Similarly, the nuclei of oligodendroglial tumors were labeled. There was no apparent correlation between the staining intensity and histological grade. Astrocytic components within the tumors were generally less or not stained. Astrocytic tumors were also positive with the Olig2 antiserum to a lesser extent, and the difference between oligodendroglial and astrocytic tumors was demonstrated by a statistical analysis. Olig2 and glial fibrillary acidic protein were expressed in a mutually exclusive manner, and Olig2 expression was cell-cycle related. Neither central neurocytoma nor schwannoma cases were stained. Our antibody was demonstrated to be useful in recognizing normal oligodendrocytes on paraffin sections, and applicable in diagnosis of some brain tumors.

Fed-batch production of citric acid by Candida lipolytica grown on n-paraffins

This study reports on the effects of fermentor agitation and fed-batch mode of operation on citric acid production from Candida lipolytica using n-paraffin as the carbon source. An optimum range of agitation speeds in the 800-1000 rpm range corresponding to Reynolds numbers of 50000-63000 (based on initial batch conditions) seemed to give the best balance between substrate utilization for biomass growth and citric acid production. Application of multiple fed-batch feedings can be used to extend the batch fermentation and increase final citric acid concentrations and product yield. The three-cycle fed-batch system increased overall citric acid yields to 0.8-1.0 g citricacid/g n-paraffin, approximately a 100% improvement in product yield from those observed in the single cycle fed-batch system and a 200% improvement over normal batch operation. The three-cycle fed-batch mode of operation also increased the final citric acid concentration to 42 g/l from about 12 and 6g/l for single fed-batch cycle and normal batch modes of operation, respectively. Increased citric acid concentrations in three-cycle fed-batch mode was achieved at longer fermentation times.

Exposure of babies to C15–C45 mineral paraffins from human milk and breast salves

Mineral paraffins widely occur in foods, but are also ingredients of body lotions, lip sticks, and breast salves. In this study it is shown that mineral paraffins are detectable in human milk. Thirty three human milk samples were found to contain mineral C(15)-C(45) paraffins at a mean concentration of 95+/-215mg/kg fat and a maximum of 1300mg/kg. The mineral paraffins found in human milk had average molecular weights between C(23) and C(33), and often more than half of the paraffins were below C(25). Beside exposure of babies via human milk, the intake by direct licking off salves (in the worst case consisting of vaseline) from the breast of their nursing mothers may be much higher. In a worst case situation, daily intake from breast care products by babies is estimated to reach 40mg/kg bw. Many compositions do not comply with the specifications and a temporary group ADI of 0-4mg/kg bw established by the SCF. This possible exposure of babies either calls for a toxicological re-evaluation of the mineral paraffins or for measures ensuring that exposure of babies is reduced.

Viscosity properties of mineral paraffinic base oils as a key factor in their primary biodegradability

The primary biodegradability of two types of paraffinic base oils (solvent and catalytically dewaxed oils) and their blends was evaluated using the CEC L-33-A-93 test. The biodegradability values varied between 10% and 75%. Base oil mixtures displayed varying contents in aromatic and polar compounds and a wide range of kinematic viscosity (KV) values, from roughly 10 to 600 cSt (at 40 degrees C), while their viscosity indices were almost constant (90-100). The biodegradability of oils was closely related to their content in polycyclic aromatic hydrocarbons and was also decreasing with kinematic viscosity. For the two types of base oils, a linear relationship could be set between the biodegradation percentages and the logarithms of KV values. These results show that, beside overall chemical features such as the contents in aromatic compounds, KV may be a prominent parameter for assessing the primary biodegradability of mineral base oils.

Use of the paraffin wax baiting system for identification of Pseudomonas aeruginosa clinical isolates

Pseudomonas aeruginosa is the primary pathogen among the Pseudomonads and is known for its minimal nutritional requirements, capacity to use paraffin as a sole carbon source, and biofilm formation. Because the ability of Pseudomonads to grow on paraffin is not commonly found among human pathogens and the primary Pseudomonas human pathogen is P. aeruginosa, we studied the adaptation of the paraffin baiting system for the growth and identification of clinical isolates of P. aeruginosa. We also studied the effectiveness of combining a fluorescence assay measuring fluorescein (pyoverdin) production and oxidase test with the paraffin baiting assay for P. aeruginosa speciation. Strains were tested for the capacity to use paraffin as a sole carbon source using the paraffin baiting system with Czapek's minimal salt medium. Of 111 P. aeruginosa clinical isolates tested for using paraffin as a sole carbon source, 45% exhibited growth on paraffin at 24 h and 76.6% exhibited growth on paraffin at 48 h. The ability of the reference strains and clinical isolates were then tested for their ability to associate with the paraffin slide in the presence of an additional carbon source. Of 111 P. aeruginosa clinical isolates tested, 85 strains (76.6%), and 102 (93%) were associated with the paraffin surface at 24 and 48 h. We successfully combined fluorescence and oxidase assays with the paraffin baiting system for identification of P. aeruginosa. The simple and inexpensive paraffin baiting system is a useful method for the identification and study of P. aeruginosa suitable for both the clinical and research laboratory.

Acid-fastness of Nocardia asteroides GUH-2 cultured in brain heart infusion broth supplemented with paraffin

Nocardia asteroides GUH-2 was not acid-fast when grown in brain heart infusion (BHI) broth. When grown in BHI broth supplemented with paraffin, many filamentous cells showed acid-fastness after treatment with 1% acid-alcohol as the decolorizing agent. When treated with 3% acid-alcohol, filamentous cells were not acid-fast. In addition to the acid-fast filamentous cells of nocardiae, unknown acid-fast spherical bodies were observed in the paraffin-supplemented BHI broth cultures.

Pathological hepatic accumulation of long-chain n-alkanes ("paraffin liver") in cows (Harbitz and Fölling, 1940). An overlooked discovery. Description of lesions and identification of alkanes

About 50 years ago crystalline deposits of a substance representing approximately 7 per cent wet tissue weight and believed to be hentriacontane or a mixture of similar long-chain n-alkanes (30-34 carbon atoms) were detected in two discoloured and swollen cow livers. Stored purified extracts from these livers were recently reanalysed using gas chromatography and mass spectrometry. They were found to contain about equal amounts of nonacosane and hentriacontane with a small admixture of tritriacontane and other long carbon-chain alkanes. On the basis of histological findings, five additional cases of "paraffin liver" in cows have been recorded. In the discussion comparison is made with the only known case of a similar disorder in a human, visceral accumulation of the same three alkanes as in the cows, which was recently described in the literature. Concerning the origin of the deposits, importance is given to the fact that the long-chain alkanes with odd carbon numbers identified both in cattle and man predominate in the cuticular waxes of many dietary plants. The very large quantities of the abnormal substance in the cow livers indicate low toxicity, and evidently accumulation over long periods of time.

Prediction of lymph node involvement in breast cancer by detection of altered glycosylation in the primary tumour

Axillary lymph node metastases at the time of diagnosis of breast cancer is the most accurate predictor of long-term prognosis. However, in patients treated by conservative surgery lymph node status often remains unknown. We have investigated the relation between changes in glycosylation of primary breast cancer cells, as judged by lectin binding, and the presence of axillary lymph node metastases. In a 24-year retrospective study, paraffin-embedded sections of 373 primary breast cancers were stained for the binding of Helix pomatia lectin (HPA). There was a strong association between HPA binding and presence of lymph node metastases, but no association with tumour size, histological grade, S-phase fraction, or patient age at diagnosis. This relation was confirmed by multiple regression analysis (in both survival and relapse free survival models) in which the prognostic significance of HPA binding was lost once nodal status had been introduced into the models. Life tables calculated for lymph-node positive versus lymph-node negative and HPA staining versus non-staining patients were almost identical over 15 years of follow-up. We propose that HPA recognises a glycoprotein that is associated with metastasis (to axillary lymph nodes and elsewhere) and poor prognosis in breast cancer. HPA binding to paraffin sections of primary tumour could aid difficult treatment decisions by providing an additional assessment of staging and likely long-term patient prognosis.

The use of paraffin wax metabolism in the speciation of Mycobacterium avium-intracellulare

Paraffin-wax utilisation or baiting of Mycobacterium avium-intracellulare (MAI) complex organisms and other 'atypical mycobacteria' and the inability of Mycobacterium tuberculosis to utilise paraffin are known and useful if forgotten facts. Strains of possible AIDS-related MAI have been introduced into Czapek broth devoid of any carbon source other than paraffin-wax coated slides. Replicate slides showing 'in situ' growth were subjected to the following battery of tests: acid alcohol fast staining and microscopic examination of 'in situ' growth, tellurite reduction in 3 days, absence of urea hydrolysis, inability to reduce nitrates and inability to hydrolyse Tween 80. The system has been utilised to isolate and identify MAI organisms in blood from AIDS patients. The simplicity, low cost, and reduced risk of contamination make the system especially suitable for small rural laboratories and field stations as well as laboratories in developing countries.

Changes in neutrophil surface protein composition accompany phagocytosis

Phagocytosis is a critical host defense mechanism of neutrophils. In this study, membrane protein changes occurring during phagocytosis were studied in human neutrophils using surface radiolabeling before or after phagocytosis of various target particles. Cells were labeled at the cell surface using lactoperoxidase-catalyzed iodination or neuraminidase-galactose oxidase-NaB3H4, galactose oxidase-NaB3H4, or periodate-NaB3H4 techniques. Such studies are complicated by the fact that these techniques identify many surface proteins on the phagocyte, and labeling after phagocytosis occurs often results in radiolabeling proteins of the target particle, thus making changes in cell-surface proteins more difficult to detect. Immunoprecipitation with monoclonal antibody AHN-1, which reacts with a carbohydrate present on several human neutrophil surface proteins and inhibits phagocytosis, eliminated interference caused by radiolabeled proteins of the target particle and simplified analysis by restricting the study to a limited number of proteins. AHN-1 immunoprecipitated less radiolabeled protein from neutrophils labeled after phagocytosis of particles opsonized with IgG or complement than from cells labeled before phagocytosis. Isolation of phagocytic vesicles containing opsonized emulsified paraffin oil demonstrated that three proteins of mol wt 105,000, 140,000, and 170,000 recognized by AHN-1 were internalized in the phagocytic vesicle during phagocytosis.

Anthrenus sp. The paraffin block eater bug

Review of several years-old, paraffin-embedded specimens showed unusual damage, especially of the sectioned surface of hyperkeratotic lesions. The larva of Anthrenus sp., feeding on the embedded material, was identified as the causative agent. Normally found in birds' nests, this species prefers keratin for nutrition, and can therefore damage histopathology collections.