Paul M. Heidger

Comparison of a virtual microscope laboratory to a regular microscope laboratory for teaching histology.

Emerging technology now exists to digitize a gigabyte of information from a glass slide, save it in a highly compressed file format, and deliver it over the web. By accessing these images with a standard web browser and viewer plug‐in, a computer can emulate a real microscope and glass slide. Using this new technology, the immediate aims of our project were to digitize the glass slides from urinary tract, male genital, and endocrine units and implement them in the Spring 2000 Histology course at the University of Iowa, and to carry out a formative evaluation of the virtual slides of these three units in a side‐by‐side comparison with the regular microscope laboratory. The methods and results of this paper will describe the technology employed to create the virtual slides, and the formative evaluation carried out in the course. Anat Rec (New Anat) 265:10–14, 2001.

Integrated approach to teaching and testing in histology with real and virtual imaging

The University of Iowa College of Medicine histology teaching laboratory incorporates extensive Web‐ and computer‐based teaching modalities, including the Virtual Microscope (VM), as emerging learning aids in histology and pathology laboratory instruction. We report here our experience in offering a multiple resource‐based approach to laboratory instruction while retaining the opportunity and requirement of examining actual microscopic slide preparations with the microscope. Acceptance of this approach has been high among our students and faculty, and performance levels established over years of teaching histology by traditional means have been maintained. Anat Rec (New Anat) 269:107–112, 2002.

Dual roles of E-cadherin in prostate cancer invasion.

The role(s) of E‐cadherin in tumor progression, invasion, and metastasis remains somewhat enigmatic. In order to investigate various aspects of E‐cadherin biological activity, particularly in prostate cancer progression, our laboratory cloned unique subpopulations of the heterogeneous DU145 human prostatic carcinoma cell line and characterized their distinct biological functions. The data revealed that the highly invasive, fibroblastic‐like subpopulation of DU145 cells (designated DU145‐F) expressed less than 0.1‐fold of E‐cadherin protein when compared to the parental DU145 or the poorly invasive DU145 cells (designated DU145‐E). Experimental disruption of E‐cadherin function stimulated migration and invasion of DU145‐E and other E‐cadherin‐positive prostate cancer cell lines, but did not affect the fibroblastic‐like DU145‐F subpopulation. Within the medium of parental DU145 cells, the presence of an 80 kDa E‐cadherin fragment was detected. Subsequent functional analyses revealed the stimulatory effect of this fragment on the migratory and invasive capability of E‐cadherin‐positive cells. These results suggest that E‐cadherin plays an important role in regulating the invasive potential of prostate cancer cells through an unique paracrine mechanism.

Heterogeneous Expression of Invasive and Metastatic Properties in a Prostate Tumor Model.

Cellular heterogeneity of neoplasia is well demonstrated in the Dunning R-3327 rat prostate adenocarcinoma. In this study, we measured the differential expression of invasive and metastatic properties of this prostate model by cloning from a heterogeneous parental cell line. Four cell clones were derived and characterized by morphological studies, E-cadherin expression, and invasive and metastatic potential. Three of the clones (clones 5′A, 5′C, and 5′D) demonstrated a fibroblastic morphology and were anchored to the substrate by loose microvillous processes. The fourth clone (clone 5′B) grew in tight clusters and displayed many closely spaced microvilli, long overlapping cytoplasmic regions with well-defined junctional complexes. The parental line (R3327-5′) demonstrated a combination of both these growth patterns. E-cadherin expression was absent in clones 5′A, 5′C, and 5′D and very prominent in clone 5′B, when compared to the parental line. The absence of E-cadherin expression correlated with increased invasiveness, as measured in an in vitro invasion assay. Subcutaneous injections of clones 5′A, 5′C, and 5′D yielded lung metastases and no primary tumors at the site of inoculation while clone 5′B was tumorigenic and produced fewer lung metastases in vivo. These clones, therefore, provide a potential for studying a variety of molecules involved in prostate cancer invasion and metastasis, especially for the direct testing of the significance of E-cadherin expresssion in prostate cancer progression.

Spermatic granuloma of vas deferens after vasectomy in rhesus monkeys and men Light and electron microscopic study

Spermatic granuloma of the vas deferens is a common complication of vasectomy which has received scant morphologic study. This study investigated the light and electron microscopic structure of such granulomas detected in rhesus monkeys (Macaca mulatta) and man after various modes of vasectomy and postoperative periods. Unilateral experimental vasectomy in monkeys was performed by either silk ligation or clasp occlusion; in 4 of 13 ligated animals and 5 of 5 clasp vasectomized animals granulomas developed at the site of fasectomy. In man, portions of the vas deferens were excised adjacent to the site of vasectomy preparatory to vasovasostomy. Of 5 patients studied, unilateral spermatic granulomas developed in 3. Such granulomas in both monkey and man were characterized by (1) masses of sperm surrounded by epithelioid cells and connective tissue, and (2) multiple epithelial-lined channels which often contained sperm and spermiophages. In both species, fine structural characteristics of the epithelium lining such channels closely resembled those of the principal cells of the normal vas. Spermiophagic cells included macrophages, epithelioid cells, and, in the monkey only, neutrophils. Lymphocytic invasion was a common feature of the human granulomas but was found only occasionally in the monkey granulomas. As a greater number of granulomas are studied in humans and monkeys, it is hoped that the processes underlying granuloma formation and the role of such granulomas in the development of complications after vasectomy will be clarified.

Electron Microscopic and Histochemical Characterization of Intra-Arterial Cushions of the Rat and Porcine Uterine Vascular Bed

Scanning and transmission electron microscopic studies, together with histochemical investigations, were conducted on rat and porcine intra-arterial cushions from the uterine vascular bed. In the rat, the fine structure of these cushions closely resembled that previously described in the rat kidney. The cushions were composed of modified smooth muscle, circularly disposed in an incomplete, raised band surrounding the entrance to arterial branches. These muscle cells projected as attenuated processes throughout the loosely organized, PAS-positive stroma, and established close contact with thin endothelial extensions projecting from the base of the surface endothelial cells. Scanning electron microscopic observations of furrows on the endothelial surface gave rise to the suggestion that such contacts might mediate muscular control of endothelial surface topology. In similar cushions from the pig uterine artery, the smooth muscle of the cushions was much more compactly organized, and was disposed radially, rather than circumferentially, within the cushion structure. The enzyme histochemical profile of porcine cushions did not differ appreciably from that of normal vascular smooth muscle and endothelium, suggesting the maintenance of a metabolic similarity with adjacent tissues. These studies clarify the fine-structural basis for recently reported contraction and relaxation of uterine artery cushions during ischemia and perfusion of the rat uterine vascular bed, and thus, for their functional role in the regulation of uterine vascular flow.

Ultrastructure of crystalloid inclusions in the dog and rat epididymis.

Abstract Fine structural studies of the epididymis of mature mongrel dogs and of Sprague-Dawley rats were undertaken in conjunction with research dealing with the effects of vasectomy upon this organ. This paper reports the observation of crystalloid and lamellar inclusions present in these species following fixation of the epididymis in 5 % glutaraldehyde, post-fixation in osmium, and routine processing for electron microscopy. In the dog, crystalloid inclusions were observed within the cauda epididymidis of unoperated and vasectomized animals. They were found within the apical cytoplasm of principal cells in association with the Golgi apparatus and endoplasmic reticulum, and in some instances, in close proximity to the nucleus. These crystalloids exhibited a 12 nm periodicity and often measured over 3 μm in length. In the rat, two types of inclusions were found, one within mitochondria of clear cells from unoperated animals and another within membrane-bound bodies of principal cells from the caput epididymidis of unoperated and vasectomized animals. The mitochondria which contained inclusions were basally located and were observed in stacks of up to eight elongate mitochondria each. The mitochondrial inclusions exhibited a complex lamellar structure with an approximate periodicity of 36 nm. In contrast, the crystalloid inclusions found within principal cells were sequestered within supranuclear cytoplasmic bodies which increased in number with age. Such crystalloids exhibited a linear periodicity of 11–13.5 nm, but the precise lattice structure remains to be determined. Although certain aspects of the morphology of these bodies suggests a relationship to microbodies, we have been unable to demonstrate catalase activity within them. At present, neither the origin of crystalloid structures described, nor their relationship to epididymal physiology is clear.

Epithelial-Mesenchymal Molecular Interactions in Prostatic Tumor Cell Plasticity

Tumor cell plasticity poses a significant clinical challenge in that the fate and function of tumor cells can be elusive until a tumor mass is evident. An overview of key molecular events in prostate cancer, initiated by an epithelial-to-mesenchymal transition, highlights the cooperative interactions of diverse prostatic subpopulations within heterogeneous tumors. A remarkable example of plasticity is demonstrated by subpopulations of E-cadherin-positive and E-cadherin-negative tumor cells working in concert to form de novo vasculogenic-like networks while expressing vascular-associated genes, called vasculogenic mimicry, resulting in acquisition of the metastatic phenotype. A better understanding of the molecular mechanisms underlying prostate tumor cell plasticity may provide new prognostic markers for clinical diagnosis and novel therapeutic intervention strategies for disease management.

Fine structural studies of induced tumors arising within the prostatic complex of Lobund-Wistar rats.

Morris Pollard, Phyllis Luckert, and colleagues have reported the occurrence of spontaneously arising tumors of the prostatic complex in aged Lobund‐Wistar (L‐W) rats, and have also shown that the genesis of such tumors may be accelerated by means of intravenous administration of methylnitrosourea, followed by androgen supplementation.

Stereological Study of Leydig Cell Density in the Guinea Pig Testis

Stereological analysis of Leydig cell and macrophage volume density along the long axis of the guinea pig testis was assessed quantitatively by histometric point counting. Morphological identification of Leydig cells was accomplished by staining for 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD), whereas macrophages were identified by vital staining (trypan blue). The average percentage of Leydig cell density constitutes about 10.17 +/- 0.23% at the cranial level (level 1) and about 8.8 +/- 0.21% at the caudal level (level 4). Leydig cell density through four testicular levels showed no significant difference among levels 1, 2, and 3, whereas level 4 was significantly different. The percentage of macrophage density, on the other hand, was approximately 0.4% +/- SEM per cross-sectional profile. It may thus be concluded that the macrophage density within the guinea pig testis does not bias histometric studies of the Leydig cell population to any significant degree, but that regional differences in Leydig cell volume density could influence validity of sampling if tissue procurement is from different testicular levels in successive experiments.