Nesidioblastosis in sickle cell disease.

Although the endocrine pancreas appears to play an important role in the pathophysiology of sickle cell disease, very little is known about the morphologic changes in this tissue. Our study was initiated to delineate the microscopic features of the endocrine pancreas in a large autopsy series of sickle cell hemoglobinopathies. From more than 650 cases archived at the Centralized Pathology Unit for Sickle Cell Disease (Mobile, AL), 224 autopsy cases were identified for review of clinical and gross autopsy findings and/or for microscopic studies, including histochemical stains (trichrome, reticulin, iron), and immunohistochemical stains (insulin, glucagon, somatostatin, and pancreatic polypeptide). The gross examinations were recorded as unremarkable in 65% of the autopsies. In childhood and adolescence (< or = 18 years), pancreas weights (50.76 +/- 5.16SE gm) were significantly greater (p < 0.0001) than age-matched controls (30.42 +/- 3.59SE gm). In adulthood, pancreas weights (108.34 +/- 5.29SE gm) were not significantly different from controls (110 gm). Microscopic findings included vascular congestion (48%), edema (65%), siderosis (31%), and nesidioblastosis (76%), which included islet cell dispersion (53%), hyperplasia (23%), and hypertrophy (25%). Analysis by age groups suggested that islet cell dispersion/hyperplasia persists unchanged, whereas diameters of compact islets tend to increase with age. These findings may be related to local tissue hypoxia and/or increased metabolic energy needs in sickle cell disease.

Remodeling of lung interstitium but not resistance vessels in canine pacing-induced heart failure.

We previously showed that pacing-induced heart failure in dogs results in an enhancement of pulmonary vascular reactivity. In the present study we hypothesized that enhanced matrix deposition and structural remodeling of lung resistance microvessels would underlie these functional changes. Using biochemical measures, we found no difference in the normalized lung content of hyaluronan, uronic acid, and collagen between control dogs and dogs paced for 1 mo, although lung dry weight and noncollagen protein content increased significantly in the paced group (P < 0.05). From separate Formalin-fixed lung lobes, 5-microm frozen sections were prepared and stained with Masson's trichrome, and vascular structure was evaluated using standard morphometric techniques. When perivascular fluid cuffs were excluded from the measure of wall thickness, collagen and media volume fractions in any size range did not differ between paced and control groups. Similarly, in the paced group, medial thickness in <400-microm arterial or venular microvessels did not vary significantly from that in the controls. In contrast, the relationship of interstitial fluid pressure to lung water was significantly shifted to the right in the paced group, such that normal tissue pressures were observed, despite the increased water content. We conclude that although 1 mo of pacing-induced heart failure results in altered interstitial function, the attendant pulmonary hypertension and/or hormonal responses are insufficient to induce medial hypertrophy or other remodeling of the extra-alveolar microvasculature.

The developmentally regulated expression of serum response factor plays a key role in the control of smooth muscle-specific genes.

Serum response factor (SRF) is a MADS box transcription factor that has been shown to be important in the regulation of a variety of muscle-specific genes. We have previously shown SRF to be a major component of multiple cis/trans interactions found along the smooth muscle gamma-actin (SMGA) promoter. In the studies reported here, we have further characterized the role of SRF in the regulation of the SMGA gene in the developing gizzard. EMSA analyses, using nuclear extracts derived from gizzards at various stages in development, showed that the SRF-containing complexes were not present early in gizzard smooth muscle development, but appeared as development progressed. We observed an increase in SRF protein and mRNA levels during gizzard development by Western and Northern blot analyses, with a large increase just preceding an increase in SMGA expression. Thus, changes in SRF DNA-binding activity were paralleled with increased SRF gene expression. Immunohistochemical analyses demonstrated a correspondence of SRF and SMGA expression in differentiating visceral smooth muscle cells (SMCs) during gizzard tissue development. This correspondence of SRF and SMGA expression was also observed in cultured smooth muscle mesenchyme induced to express differentiated gene products in vitro. In gene transfer experiments with SMGA promoter-luciferase reporter gene constructs we observed four- to fivefold stronger SMGA promoter activity in differentiated SMCs relative to replicating visceral smooth muscle cells. Further, we demonstrate the ability of a dominant negative SRF mutant protein to specifically inhibit transcription of the SMGA promoter in visceral smooth muscle, directly linking SRF with the control of SMGA gene expression. Taken together, these data suggest that SRF plays a prominent role in the developmental regulation of the SMGA gene.

Polymerase chain reaction facilitates archival autopsy studies of sickle cell disease.

Archival autopsy studies of sickle cell disease have often been hampered by inadequate documentation of the genotype. Although the polymerase chain reaction (PCR) has been applied to the prenatal diagnosis of sickle cell disease, its use has not been reported in archival studies of sickle cell disease. In this study, DNAs from formalin-fixed, paraffin-embedded archival tissues were amplified by PCR and analyzed by dot-blot hybridization using allele-specific oligonucleotides. These S and C genotypes for 9 of 10 archival specimens studied blindly were correctly identified by PCR. The tenth specimen consistently failed to amplify by PCR, yielding no result. These data demonstrate the utility of PCR for retrospective identification of the genotype of sickle cell disease. This application of PCR will significantly expand the number of autopsy cases suitable for retrospective studies of the morbidity and mortality of sickle cell disease.

Intestinal trichomonads (Tritrichomonas mobilensis) in the natural host Saimiri sciureus and Saimiri boliviensis.

A retrospective study of cecal and colonic tissues from 28 squirrel monkeys (Saimiri sciureus and Saimiri boliviensis) demonstrated enteric trichomonads within luminal crypts. Twenty-one of 28 (75%) had trichomonads in the mucosal epithelium either in cup-like depressions or intraepithelial vacuoles. Organisms were also beneath the superficial luminal mucosal epithelium and between the basement membrane and crypt epithelial cells. Immunoperoxidase staining also identified organisms within the lamina propria and submucosa. Additional histologic changes included mucosal ulceration, multifocal cryptitis, and focal epithelial necrosis. Most areas containing trichomonads did not have an associated inflammatory response.

Pathogenicity of Tritrichomonas mobilensis: subcutaneous inoculation in mice.

The standard "subcutaneous mouse assay" was used to investigate the inherent pathogenicity of Tritrichomonas mobilensis, an intestinal parasite of squirrel monkeys. C57B1/6 mice given subcutaneous bilateral inocula of T. mobilensis died by day 4 postinoculation with lesions too small to be measured. Control mice similarly inoculated with pathogenic and nonpathogenic strains of Trichomonas vaginalis survived the challenge and produced lesions on day 6 with mean volumes in agreement with previous reports. CD1 mice similarly inoculated with standard and double doses of trichomonads (T. mobilensis) again produced small lesions. CD1 mice inoculated at double dosage were moribund or dead on days 5 and 6, respectively, postinoculation. Necropsies were performed on dead and sacrificed mice. Tissues were obtained from internal organs for histology and culture. Unexpectedly, trichomonads were cultured from liver and lung of C57B1/6 mice at the standard level of inoculation and liver, lung, and spleen of CD1 mice at the higher level of inoculation. Although trichomonads are normally considered surface-dwelling noninvasive organisms, the penetration of trichomonads to deep tissues is not without precedent. Tritrichomonas foetus and Trichomonas gallinae are known to invade tissues of their respective hosts. Trichomonas vaginalis has been demonstrated in subepithelial areas of both the prostate gland and cervix of humans. The ability of several species of trichomonads to invade tissues and/or migrate to other sites in their hosts suggests a need for revision of the concept of trichomonads as strictly lumen or surface-dwelling parasites.

Intraprostatic spermatozoa.

Spermatozoa have not previously been described within the prostate gland. Nine of one hundred prostates of nonhospitalized males obtained from autopsy during the course of medicolegal death investigation were found to contain spermatozoa. The potential role of spermatozoa in the pathogenesis of corpora amylacea/calculi formation, granulomatous inflammation, local antigenic stimulation, and carcinogenesis is considered.

Subepithelial organisms in trichomonal cervicitis.

Trichomonas vaginalis is usually described as a surface-dwelling, noninvasive organism. Most studies of the pathogenicity of this organism have been derived from cytologic studies of uterine cervical epithelium. We employed specific immunoperoxidase techniques that allow the identification of organisms in cytologic and histologic specimens. In a case of trichomonal cervicitis these organisms were demonstrated both on the epithelial surface and in subepithelial tissues. Interpretations and implications of these findings are discussed.

Experimental genital trichomoniasis in the squirrel monkey (Saimiri sciureus).

The squirrel monkey (Saimiri sciureus) has been proposed as a model for urogenital trichomoniasis in man, but has not been accepted as such because of the purported presence of naturally occurring vaginal trichomonads in this animal. The study published here shows that these are easily eradicated organisms of intestinal origin, which eliminates the potential confusion created by them. In addition, our experiments have shown that the hormonal status of primates seems to be a determinant in successfully establishing experimental trichomoniasis. This experimental infection recapitulates the clinical observations sufficiently to warrant the use of this model for studies of vaginal trichomoniasis.

Atrophy and proliferation in the young adult prostate.

Atrophic and proliferative changes in the prostate gland are regarded as beginning in middle age and characterizing the prostates of older men. A total of 51 prostates of men between 19 and 29 years old demonstrated a spectrum of proliferative abnormalities, including ductal and glandular hyperplasia, atypical hyperplasia, dysplasia, carcinoma in situ and incipient adenocarcinoma. The majority of the prostates also contained substantial areas of atrophy. Patterns of atrophic change included cystic dilatation of glands with flattened epithelium apparently secondary to obstructive hyperplasia of ductal epithelium, areas comparable to sclerotic atrophy of the aged prostate and segments having the appearance of a prepubertal unstimulated prostate. These observations contrast sharply with conventional concepts of the biology of the prostate gland, and suggest a number of hypotheses regarding the early antecedents and evolution of prostatic carcinoma and cancer in general.

Tritrichomonas mobilensis n. sp. (Zoomastigophorea: Trichomonadida) from the Bolivian squirrel monkey Saimiri boliviensis boliviensis.

A trichomonad flagellate, Tritrichomonas mobilensis n. sp., is described from the large intestine of the squirrel monkey, Saimiri boliviensis boliviensis. The organism has a lanceolate body 7-10.5 micrometers in length; a well developed undulating membrane; a stout, tubular axostyle with periaxostylar rings that terminate in a cone-shaped segment projecting from the posterior end of the cell; and a moderately wide costa. The anterior flagella are about as long as the body, and the recurrent flagellum is of the acroneme type. All its characteristics suggest that the new species belongs in the Tritrichomonas augusta type of the subfamily Tritrichomonadinae.

Trichomonas vaginalis in the prostate gland.

Although the prostate gland is believed to serve as a parasite reservoir in trichomoniasis in men, and clinical association of trichomonads with prostatitis is common, there has been, to our knowledge, no unequivocal demonstration of Trichomonas vaginalis within the prostate gland. Using established immunoperoxidase procedures, we have positively identified trichomonads in the prostatic urethra, glandular lumina, submucosa, and stroma. Foci of nonspecific acute and chronic inflammation, as well as intraepithelial vacuolization, were associated with the infection. The finding of trichomonads within and beneath glandular epithelium necessitates reevaluation of the traditional view of T vaginalis as a strictly surface-dwelling organism.