High‐definition optical coherence tomography of melanocytic skin lesions

High‐definition optical coherence tomography (HD‐OCT) scanners have recently been developed. We assessed micromorphological HD‐OCT correlates of benign naevi (BN) and malignant melanoma (MM). 28 BN and 20 MM were studied using HD‐OCT and histology. Epidermal honeycomb/cobblestone pattern, regular junctional cell nests, and edged papillae are more often observed in BN, whereas fusion of rete ridges, pagetoid cells and junctional and/or dermal nests with atypical cells are more frequently seen in MM. A high overlap of HD‐OCT features in BN and MM was observed and in 20% of MM we did not find evidence for malignancy in OCT images at all. Using HD‐OCT it is possible to visualize architectural and cellular alterations of melanocytic skin lesions. The overlap of HD‐OCT features seen in BN and MM and the absence of suspicious HD‐OCT features in some MM represents an important limitation of HD‐OCT affecting the sensitivity of HD‐OCT in diagnosing MM.

High‐definition optical coherence tomography and the corresponding vertically sectioned histology of a compound naevus.     

Suitability of antral follicle counts and computer-assisted analysis of ultrasonographic and magnetic resonance images for estimating follicular reserve in porcine,ovine and bovine ovaries ex situ

This study was conducted to determine if correlations exist between the numbers of microscopic follicles comprising ovarian follicular reserve (OFR) and antral follicle counts (AFCs), and to assess the usefulness of computerized analyses of ovarian ultrasonograms and magnetic resonance (MR) images for estimating OFR in excised porcine, ovine and bovine ovaries. As a pre-requisite to these analyses, we characterized and compared ovarian cortical histomorhpology and follicle populations in the three species varying in prolificacy and overall reproductive longevity, and hence the total number of microscopic and antral follicles. Ultrasonographic and MR images were obtained at the scanner settings optimized to provide opposing contrasts between antral follicles and the ovarian stroma. Commercially available ImageProPlus® analytical software was used to calculate numerical pixel values (NPVs) and pixel heterogeneity (standard deviation of the pixel values) along the computer-generated lines (4–6) placed in the area corresponding to the ovarian cortex. The numbers of primordial (r = 0.38, P < 0.01) and intermediate follicles (r = 0.37, P < 0.01) were correlated with the numbers of antral follicles in bovine ovarian sections. The numbers of primordial (r = 0.28, P < 0.05), intermediate (r = 0.31, P < 0.01) and primary follicles (r = 0.27, P < 0.05) correlated directly with mean NPVs of the ultrasonographic ovarian images in cattle. There was a negative correlation between primary follicle numbers and NPVs of MR images (3D FAST-SPOILED GRADIENT ECHO) of the porcine ovarian cortex (r = −0.31, P < 0.05). To summarize, the numbers of primordial and intermediate follicles could only be estimated from AFCs in cows. Using ultrasound NPVs, the numbers of primordial, intermediate and primary follicles could be directly estimated in bovine ovaries and the quantitative image attributes of MR images were useful for quantifying porcine primary follicles. The bovine ovarian model is compatible with human situation and hence future studies should be undertaken to ascertain the usefulness of AFCs and ultrasonographic image analyses for estimating OFR in women.     

Identification of Metal Oxide Nanoparticles in Histological Samples by Enhanced Darkfield Microscopy and Hyperspectral Mapping

Nanomaterials are increasingly prevalent throughout industry, manufacturing, and biomedical research. The need for tools and techniques that aid in the identification, localization, and characterization of nanoscale materials in biological samples is on the rise. Currently available methods, such as electron microscopy, tend to be resource-intensive, making their use prohibitive for much of the research community. Enhanced darkfield microscopy complemented with a hyperspectral imaging system may provide a solution to this bottleneck by enabling rapid and less expensive characterization of nanoparticles in histological samples. This method allows for high-contrast nanoscale imaging as well as nanomaterial identification. For this technique, histological tissue samples are prepared as they would be for light-based microscopy. First, positive control samples are analyzed to generate the reference spectra that will enable the detection of a material of interest in the sample. Negative controls without the material of interest are also analyzed in order to improve specificity (reduce false positives). Samples can then be imaged and analyzed using methods and software for hyperspectral microscopy or matched against these reference spectra in order to provide maps of the location of materials of interest in a sample. The technique is particularly well-suited for materials with highly unique reflectance spectra, such as noble metals, but is also applicable to other materials, such as semi-metallic oxides. This technique provides information that is difficult to acquire from histological samples without the use of electron microscopy techniques, which may provide higher sensitivity and resolution, but are vastly more resource-intensive and time-consuming than light microscopy.     

Randomized study comparing endoscopic ultrasound-guided Trucut biopsy and fine needle aspiration with high suction

H. Gerke, M. K. Rizk, A. D. Vanderheyden and C. S. Jensen
Randomized study comparing endoscopic ultrasound-guided Trucut biopsy and fine needle aspiration with high suction
Objectives:  Endoscopic ultrasound (EUS)-guided Trucut biopsy (TCB) enables acquisition of tissue cores for histological assessment. Because of the rigid needle and the spring mechanism, tissue acquisition can be difficult from regions that require sharp angulation of the echoendoscope. Fine needle aspiration with high suction (FNAHS) has been proposed as a method to obtain histological tissue cores while affording the flexibility to obtain specimens even with extreme endoscope angulation. The objective was to compare prospectively these two methods in their ability to obtain specimens for histological assessment and in their diagnostic accuracy, including cytological diagnosis when achieved.
Methods:  Eighty lesions in 77 patients were amenable to transoesophageal, transgastric or transrectal biopsy and were randomized to TCB ( n  = 44) or FNAHS ( n  = 36). Each specimen was assessed for adequacy (scoring system where a score of 0 was no material, 1–2 was considered cytological, and 3–5 was considered histological). Follow-up information was obtained to establish a gold standard final diagnosis.
Results:  The median histological scores for FNAHS and TCB were 2 and 5, respectively. Histological cores were obtained in 95.3% of TCB, as opposed to 27.8% in the FNAHS group ( P  < 0.0001). Although the diagnostic accuracy for TCB was greater than that for FNAHS (88.3% and 77.8%, respectively), this was not statistically significant ( P  = 0.24).
Conclusion:  If histological information is required, TCB is superior to FNAHS. The difference in diagnostic accuracy did not reach statistical significance due to low numbers and the fact that FNAHS often enabled a cytological diagnosis.     

Dental development of the Taï Forest chimpanzees revisited

Developmental studies consistently suggest that teeth are more buffered from the environment than other skeletal elements. The surprising finding of late tooth eruption in wild chimpanzees (Zihlman et al., 2004) warrants reassessment in a broader study of crown and root formation. Here we re-examine the skeletal collection of Taï Forest juvenile chimpanzees using radiography and physical examination. Several new individuals are included, along with genetic and histological assessments of questionable identities. Only half of the Taï juveniles employed by Zihlman et al. (2004) have age of death known with accuracy sufficient for precise comparisons with captive chimpanzees. One key individual in the former study, misidentified during field recovery as Xindra (age 8.3), is re-identified as Goshu (age 6.4). For crown formation we find that onset and duration greatly overlap captive chimpanzees, whereas root development may be more susceptible to acceleration in captive individuals. Kuykendall's (1996) equation relating captive tooth formation stage to age gives reasonable estimates of young wild subjects' true ages. Direct comparisons of tooth eruption ages are limited. A key 3.76 year-old individual likely possessed an emerging mandibular M1 at death (previously estimated from the maxillary molar as occurring at 4.1 years). Wild individuals appear to fall near the middle or latter half of captive eruption ranges. While minor developmental differences are apparent in some comparisons, our reanalysis does not show an “unambiguous pattern” of slower tooth formation in this wild environment. These data do not undermine recent developmental studies of the comparative life histories of fossil hominins.     

Limb bone histology and growth in Placerias hesternus (Therapsida: Anomodontia) from the Upper Triassic of North America

Abstract: Patterns of bone deposition are reported and deduced from mid‐shaft sections of 21 limb bones of the dicynodont Placerias hesternus from the Placerias Quarry (Upper Triassic), Arizona, USA. All sampled elements of P. hesternus have a large medullary cavity completely filled with bony trabeculae surrounded by dense cortical bone. Dense Haversian bone extends from the perimedullary region to at least the mid‐cortex in all sampled bones. Primary bone in the outer cortex of limb elements of P. hesternus is generally zonal fibrolamellar with a peripheral layer of parallel‐fibred bone. These data suggest periodic rapid osteogenesis followed by slower growth. Among dicynodonts, this strategy is most similar to growth previously reported in other Triassic (Lystrosaurus, Wadiasaurus) and some Permian taxa (Oudenodon, Tropidostoma). An external fundamental system (EFS), suggesting complete or near complete cessation of appositional growth, is present in the largest tibia. This is the first report of EFS in dicynodonts and may represent the attainment of maximum size in P. hesternus. Slow‐growing peripheral bone was observed in elements of varying size in our sample and may support a differential growth pattern between P. hesternus individuals from this locality. A complete growth series of P. hesternus, analysis of Placerias specimens from other localities, and further sampling of other Upper Triassic dicynodonts are needed to better understand a more complete picture of the growth and remodelling patterns that we have initially investigated.     

Quantitative histopathology of Oreochromis niloticus gills after copper exposure

In order to test whether histopathological changes of gills demonstrated a good dose–response relationship with water copper levels, juvenile Nile tilapia Oreochromis niloticus, of both sexes and similar mass (36·3 + 7·7 g), were kept in dechlorinated tap water (temperature 25° C, range ±1° C; pH 6·5–7·5; hardness 74·5 mg l^?1 CaCO₃) and exposed to 40 and 400 μg l^?1 of copper. Gill samples were collected after 3, 7, 14 and 21 days. Six major histopathological changes (oedema, lifting, changes in filament epithelium thickness, lamellar fusion, vasodilatation and aneurisms) and three minor ones (proliferation of the lamellar epithelium, necrosis and adjacent lamellar fusion) were found and their prevalence estimated. The extent and severity of each histopathological change were used to develop a severity gradation scale (SGS). Semi‐quantitative analysis of the histopathological changes and measurements of gill copper deposition levels revealed a good dose– and time–response relationship. Oedemas and aneurisms were significantly correlated with acute exposure periods and lamellar fusion with chronic exposure. Epithelial lifting and changes in filament epithelial thickness were seen at lower and higher metal concentrations, respectively. The data also revealed that the SGS profile of each lesion was dependent of gill copper burden.     

Utility and diagnostic accuracy of fallopian tube touch imprint cytology

OBJECTIVE: To determine the diagnostic accuracy of cytology smears in distinguishing between tube and non-tube structures. METHODS: One hundred cytology smears of fallopian tube and non-tube structures (vessels, round and ovarian ligaments) were prepared from surgically removed uterus and fallopian tube specimens and stained by the Papanicolaou method. The slides were reviewed blindly by pathologists and interpreted as tube or non-tube structures. The results were compared to the histological examination of the same specimens. FINDINGS: Results indicated an overall accuracy of 97% with a specificity of 98% and sensitivity of 96% for cytology smears, taking histology as the gold standard. Positive and negative predictive values were 96.1% and 97.9%, respectively. CONCLUSION: Cytology smears are a convenient and cost effective tool for laboratory confirmation of tubal sterilization. This method can reduce the costs of laboratory examination, especially in developing countries, where tubal sterilizations are done in large cohorts. However, histological slides remain the gold standard in cases of medicolegal problems.     

New insights into the ultrastructure, permeability, and integrity of conodont apatite determined by transmission electron microscopy

New crystalline structures have been observed in argon ion‐milled conodont elements from a diverse suite of Ordovician taxa (‘Cordylodus robustus’, Drepanoistodus suberectus, Panderodus gracilis, Plectodina? sp., Aphelognathus sp., Periodon aculeatus), using transmission electron microscopy (TEM). Electron diffraction patterns of albid tissue reveal that the component crystals are extraordinarily large, in the order of hundred(s) of microns. These large albid crystals show typical cancellate porosity, although a distinctly lamellar structure has also been observed within a large albid crystal positioned between hyaline lamellar and cancellate albid tissues. There is a distinct absence of ‘interlamellar space’ within all hyaline tissues examined, which are characterized by a polycrystalline matrix of micron‐scale elongate crystals that are both strongly aligned and tightly bound within a broader lamellar structure. Optical opacity, caused by light scattering within large (≥ 0.5 µm) pores, is also a feature of both albid and polycrystalline lamellar crown tissues. Accordingly, conodont hard tissues are differentiated by crystal size and shape, as well as inter‐ and intracrystalline porosity. These new observations highlight the structural complexities of conodont histologies and the need for more comprehensive investigations particularly of transitional crown tissues, which are not well defined by terms typically used in the literature. Their histological structures are interpreted to be a product of in vivo crystallization and thus provide new insights into the relative porosity, permeability, and inherent integrity of the tissues as well as their growth relationships. Accordingly, these data not only have implications for earlier histological and palaeobiological interpretations of conodont hard tissues but are also fundamental in determining their chemical integrity, which is crucial for characterizing palaeoseawater composition and palaeoenvironmental change. The potential for conodont apatite to retain primary chemical information depends on crystal size and permeability, so the large albid crystal domains are consistent with parallel geochemical studies that suggest that cancellate albid crown is more resistant to diagenetic modification.