Quantitative Measurement of Elasticity of the Appendix Using Shear Wave Elastography in Patients with Suspected Acute Appendicitis

Introduction

Shear wave elastography (SWE) has not been studied for diagnosing appendicitis. We postulated that an inflamed appendix would become stiffer than a normal appendix. We evaluated the elastic modulus values (EMV) by SWE in healthy volunteers, patients without appendicitis, and patients with appendicitis. We also evaluated diagnostic ability of SWE for differentiating an inflamed from a normal appendix in patients with suspected appendicitis.

Materials and Methods

Forty-one patients with clinically suspected acute appendicitis and 11 healthy volunteers were prospectively enrolled. Gray-scale ultrasonography (US), SWE and multi-slice computed tomography (CT) were performed. The EMV was measured in the anterior, medial, and posterior appendiceal wall using SWE, and the highest value (kPa) was recorded.

Results

Patients were classified into appendicitis (n = 30) and no appendicitis groups (n = 11). One case of a negative appendectomy was detected. The median EMV was significantly higher in the appendicitis group (25.0 kPa) compared to that in the no appendicitis group (10.4 kPa) or in the healthy controls (8.3 kPa) (p<0.001). Among SWE and other US and CT features, CT was superior to any conventional gray-scale US feature or SWE. Either the CT diameter criterion or combined three CT features predicted true positive in 30 and true negative in 11 cases and yielded 100% sensitivity and 100% specificity. An EMV of 12.5 kPa for the stiffest region of the appendix predicted true positive in 28, true negative in 11, and false negative in two cases. The EMV (≥12.5 kPa) yielded 93% sensitivity and 100% specificity.

Conclusion

Our results suggest that EMV by SWE helps distinguish an inflamed from a normal appendix. Given that SWE has high specificity, quantitative measurement of the elasticity of the appendix may provide complementary information, in addition to morphologic features on gray-scale US, in the diagnosis of appendicitis.     

Endothelin-1 and endothelin-converting enzyme-1 in human granulomatous pathology of eyelid: an immunohistochemical and in situ hybridization study in chalazia

Endothelin-1 (ET-1), a potent vasoconstrictor peptide, is involved in several functions of eye pathophysiology, such as regulation of intraocular tension and retinal reactive vasoconstriction. As ET-1 pro-inflammatory and fibrosing activity is emerging in different fields of pathology, we investigated the expression of ET-1 and endothelin-converting enzyme-1 (ECE-1) in chalazia, granulomatous lesions of the eyelid. ET-1 and ECE-1 were analyzed by immunohistochemistry (IHC) in twenty surgically removed chalazia, with regard to expression in eyelid structures and inflammatory infiltrate. Phenotype of ET-1 expressing inflammatory cells was established by double immunofluorescence. The cellular localization of prepro-ET-1 (pp-ET-1) mRNA and ECE-1 mRNA was studied by nonisotopic in situ hybridization (ISH). Neutrophils (PMNs), macrophages and T-lymphocytes were scattered in stroma, around alveoli and grouped in lipogranulomas. PMNs, macrophages, basal epithelium of meibomian adenomers and central ducts immunostained for ET-1. ECE-1 protein was found in meibomian adenomers, conjunctival epithelium, tarsal mucous glands and in inflammatory cells. Hybridization signals for pp-ET-1 mRNA and ECE-1 mRNA were recognized in healthy and degenerating meibomian ducts, adenomers, inflammatory cells, as well as in vessel walls. ECE-1 mRNA was also present in conjunctival epithelium and Henle's crypts. Our findings suggest that the multifunctional peptide ET-1 may have a role in molecular genesis of tissue damage in chalazia. ET-1 cytokine activity is likely to support the migration of inflammatory cells and the setting of lipogranulomas; ET-1 stimulation might contribute to proliferation of fibroblasts and collagen synthesis. ET-1 upregulation on meibomian adenomers and ducts may further enhance granulomas formation by stimulating lipid release.     

The disappearance of CD34-positive and alpha-smooth muscle actin-positive stromal cells associated with human intra-uterine and tubal pregnancies

In order to elucidate the change in alpha-smooth muscle actin (ASMA)-positive and CD34-positive stromal cells associated with pregnancy, we examined endometrial and Fallopian tube tissues from 40 patients including normal endometrium (n=10), intra-uterine pregnancy (n=10), normal Fallopian tube (n=10), and tubal pregnancy (n=10), using immunohistochemistry. In normal endometrium, only a few ASMA-positive cells were focally observed. Additionally, a wide range of CD34-positive stromal cell abundance was observed. In normal Fallopian tube mucosa, a small to moderate number of both ASMA-positive and CD34-positive stromal cells was observed. Neither ASMA-positive nor CD34-positive stromal cells were observed anywhere in the decidual stroma during both intra-uterine and tubal pregnancies. Likewise, a varying abundance of ASMA-positive cells but no CD34-positive stromal cells were observed at the fetal side during both intra-uterine and tubal pregnancies. In conclusion, the disappearance of CD34-positive and ASMA-positive stromal cells may be an indicator of decidualisation induced change in the stroma during both intra-uterine and tubal pregnancies. ASMA-positive stromal cells at the fetal side associated with pregnancy may play a role in the production of villous extracellular matrix or regulation of blood flow.     

Torsion of epiploic appendage mimic acute appendicitis

Epiploic appendagitis is a rare cause of focal abdominal pain which, depending on its localisation, can mimic a variety of abdominal diseases. We report a case of 36-year-old woman who presented with a classic signs of acute appendicitis. On examination, the obese, afebrile, and had very strong right iliac fossa tenderness and guarding. The white cell count was 12.82 x 10(9)/L, and C reactive protein count was 15.13MG/DL. She underwent emergency laparoscopic procedure after the acute appendicitis diagnosis has been established. Laparoscopic exploration of the abdominal cavity showed vermiform, no inflamed, appendix and necrotic appendix epiploica of the caecum. The treatment consisted of typical laparoscopic appendectomy and laparoscopic resection of the necrotic appendix epiploica. The patient made rapid recovery and was discharged from the hospital on second day after the operation. Histological investigation of the appendix epiploica revealed gangrenous epiploic appendage.     

Interleukin-18 (IL-18) mRNA expression and localization of IL-18 mRNA-expressing cells in the mouse uterus

Interleukin-18 (IL-18) belongs to the interleukin-1 family and was identified as an interferon-gamma inducing factor. We investigated IL-18 mRNA-expressing cells in the mouse uterus. By RNase protection assay, IL-18 mRNA and alpha subunit of IL-18 receptor mRNA were detected in the uterus. In the uterus, IL-18 mRNA levels increased during sexual maturation. In situ hybridization analysis demonstrated IL-18 mRNA-expressing cells in the mouse uterus of different ages. At 21 days of age, IL-18 mRNA-expressing cells were detected in the luminal epithelial cells and stromal cells although the IL-18 mRNA signal was weak. At 42 days of age, IL-18 mRNA signal was mainly detected in the stromal cells located near the myometrium, and in some of the luminal and glandular epithelial cells. In the uterus of 63-day-old adult mice, a strong hybridization signal for IL-18 mRNA was detected at estrus, but was weak at diestrus. IL-18 mRNA was mainly detected in the glandular epithelial cells and stromal cells. The effect of estradiol-17beta (E(2)) on IL-18 mRNA-expressing cells in the uterus was examined in ovariectomized mice. In oil-treated mice IL-18 mRNA signal was localized in luminal epithelial cells and stromal cells, while in E(2)-treated mice IL-18 mRNA signal was localized in stromal cells alone. These results suggest that the mouse uterus has an IL-18 system, and IL-18 exerts a physiological role within the uterus in a paracrine manner, and that IL-18 gene expression is regulated by estrogen.     

Fertility patterns after appendicectomy: historical cohort study

Surgical exploration for suspected appendicitis is the most common acute abdominal operation in children and young adults. However, in 20-30% of such explorations, the appendix is not inflamed. It is commonly thought that a perforated appendix may result in tubal dysfunction because of peritoneal adhesions after inflammation and a subsequent increased risk for extrauterine pregnancy and female infertility. Findings are reported from an examination of fertility patterns in women who had their appendix removed in childhood. 9840 women under age 15 years when they underwent appendicectomy between 1964 and 1983 were age-matched with 47,590 control women from the Swedish general population and followed until 1994. Women with a history of perforated appendix had a similar rate of first birth as the control women, as well as a similar distribution of parity at the end of follow-up. Women who had had a normal appendix removed had an increased rate of first births, and on average had their first child at an earlier age and reached a higher parity than control women. These findings therefore suggest that a history of perforated appendix in childhood does not seem to have long-term negative consequences upon female fertility.     

Appendicitis in pregnancy.

Over a 9-year period at one hospital 25 appendectomies were performed during pregnancy. In 20 cases the appendix was acutely inflamed. All mothers survived. Two women aborted and two went into premature labour. One of the premature infants survived. The fetal loss associated with acute appendicitis was 15%. Early diagnosis and operation is essential.     

The distribution of CD34-positive stromal cells and myofibroblasts in colorectal carcinoid tumors

In order to understand the stromal reaction associated with colorectal neoplasms, we examined specimens from 26 patients including normal colorectal tissues (n=15), carcinoid tumors (n=12), well differentiated adenocarcinomas (n=10), and poorly differentiated adenocarcinomas (n=4), using an immunohistochemical method. Myofibroblasts and CD34-positive stromal cells were distributed in the mucosa and in the area between the submucosal and subserosal layers, respectively. However, the distribution of these cells markedly changed with the invasion of neoplasms. Namely, myofibroblasts were abundant in the invasive stroma of all colorectal neoplasms. CD34-positive stromal cells were completely absent from the invasive stroma of colorectal cancers. On the other hand, CD34-positive stromal cells were absent from four out of five carcinoid tumor cases with lesions measuring less than 2 mm in size, but were present in all seven cases of carcinoid tumors measuring more than 2 mm. Double-immunostaining identified stromal cells expressing both ASMA and CD34 in several carcinoid tumor cases. Finally, no CD34-positive stromal cells were observed in the invasive stroma of colorectal cancers. However, the distribution of these cells in carcinoid tumors may depend on the lesion size. Namely, CD34-positive stromal cells existed between neoplastic nests in large-sized carcinoid tumors. Myofibroblasts in the stroma of colorectal neoplasms may originate from CD34-positive stromal cells.     

The distribution and role of myofibroblasts and CD34-positive stromal cells in normal pancreas and various pancreatic lesions

To elucidate the distribution and role of myofibroblasts and CD34-positive stromal cells in various pancreatic lesions, we performed an immunohistochemical study using a streptoavidin-biotin immunoperoxidase technique. We selected 43 pancreatic lesions from 1 biopsied, 22 surgically resected and 12 autopsied specimens: acute pancreatitis (n=3), chronic non-obstructive pancreatitis (n=4), obstructive pancreatitis (n=7), islet cell tumor (n=4), serous cystadenoma (n=7), mucinous cystadenoma (n=6), and invasive ductal carcinoma (n=12). In normal pancreas, myofibroblasts and CD34-positive stromal cells were predominantly present in the peridcutal and periacinar areas, respectively. Both myofibroblasts and CD34-positive cells were observed in the stroma of chronic pancreatitis. In four islet cell tumors, myofibroblasts were present in the stroma of the tumor center, but no CD34-positive stromal cells were identified. Additionally, myofibroblasts and CD34-positive stromal cells were located in the inner layer and the outer layer of the capsule of three islet cell tumors, respectively. In nine of the thirteen cystadenomas, only myofibroblasts were recognized in the cyst wall. In the remaining four cystadenomas, a small number of CD34-positive cells were observed in the cyst wall. In 12 invasive ductal carcinomas, the stroma possessed a lot of myofibroblasts, but there were no or few CD34-positive stromal cells. In conclusion, it seems that the abundant amount of CD34-stromal cells in the main lesions is characteristic of chronic inflammatory lesions. Myofibroblasts and CD34-positive stromal cells may play a role in regulating the tumor growth in the capsule of islet cell tumors of the pancreas.     

Increased CK5/CK8-positive intermediate cells with stromal smooth muscle cell atrophy in the mice lacking prostate epithelial androgen receptor

Results from tissue recombination experiments documented well that stromal androgen receptor (AR) plays essential roles in prostate development, but epithelial AR has little roles in prostate development. Using cell specific knockout AR strategy, we generated pes-ARKO mouse with knock out of AR only in the prostate epithelial cells and demonstrated that epithelial AR might also play important roles in the development of prostate gland. We found mice lacking the prostate epithelial AR have increased apoptosis in epithelial CK8-positive luminal cells and increased proliferation in epithelial CK5-positive basal cells. The consequences of these two contrasting results could then lead to the expansion of CK5/CK8-positive intermediate cells, accompanied by stromal atrophy and impaired ductal morphogenesis. Molecular mechanism dissection found AR target gene, TGF-β(1), might play important roles in this epithelial AR-to-stromal morphogenesis modulation. Collectively, these results provided novel information relevant to epithelial AR functions in epithelial-stromal interactions during the development of normal prostate, and suggested AR could also function as suppressor in selective cells within prostate.     

The endothelin system in human and monkey ovaries: in situ gene expression of the different components

The endothelin system is composed of three endothelin isoforms (ET-1, ET-2, and ET-3), the endothelin receptors ETA and ETB, and the endothelin-converting enzyme (ECE). Besides having a major vasoactive role, endothelins have roles in different cell types at a local level. We investigated the presence of the different components of the endothelin system in primate ovaries. Human ovaries and gonadotropin-stimulated monkey ovaries were studied using immunohistochemistry for endothelin, and in situ hybridization with probes for ET-1, ET-2, ET-3, ETA and ETB receptors, and ECE. ET-1 and ETA receptors were detected in endothelial cells and vascular smooth muscle cells, respectively, in stromal vessels adjacent to follicles and corpora lutea. ETB receptors and ET-1 were found in the endothelial cells of capillaries of corpora lutea. ECE was present in internal theca cells of secondary, de Graaf, atretic follicles, and in luteinized granulosa cells of the corpora lutea. The endothelin system components are present in or around the follicles of human and monkey ovaries. Although the components are not expressed in the same cell types, they are synthesized, mainly in follicles, by cells that are in close proximity. Thus, the endothelin system could act in a paracrine manner. ECE expression in steroid-producing cells changes its compartmentalization during follicle maturation.     

Immunocytochemical studies on endothelin in mast cells and macrophages in the rat gastrointestinal tract

 To reveal the distribution of endothelin (ET)-containing stromal cells (mast cells and macrophages), we investigated the rat gastrointestinal tract immunohistochemically using antibodies to Big ET-1, Big ET-2, Big ET-3, and mature ETs. In all the regions of the gastrointestinal tract, immunoreactivity for all the antibodies used was found in stromal cells that were located mainly in the lamina propria (not in the submucosa). The number of these cells was largest in the small intestine and smallest in the colon. Moreover, Big ET-2, which was originally identified in the gastrointestinal tract, was also found in many stromal cells, but Big ET-3-containing cells, unexpectedly, were found in almost the same number as Big ET-2-containing cells, while Big ET-1-containing cells were few. These immunopositive stromal cells seemed to be mast cells and macrophages from their histological features. Double-immunohistochemical staining revealed that 92% of the mature ETs-positive cells were mast cells; the rest were macrophages. Furthermore, we confirmed that mature ETs coexisted with ET-A or ET-B receptors in identical cells. Hence, we presume that ETs are synthesized in and secreted from stromal cells in the rat gastrointestinal tract, that their main isotypes are not only ET-2 but also ET-3, and that ETs may act in an autocrine/paracrine fashion. Accepted: 4 November 1997     

Human marrow stromal precursors are alpha 1 integrin subunit-positive

In this work we studied the expression of adhesion molecules on primate human and non-human marrow stromal cells (primary cultures and lines) and on human CD34(+) hematopoietic normal and leukemic precursors. Differential expression of alpha1 integrin subunit was observed, since this molecule was intensely expressed by marrow stroma but not detected on CD34(+) cells. We used this difference to select, in fresh bone marrow samples, alpha 1-positive cells. We found that all stromal precursors giving rise to colony-forming units-fibroblasts (CFU-F) were present in the alpha 1-positive fraction. No colonies were detected in the alpha 1-negative fraction even after 2 weeks of culture. Phenotypic studies of stromal cells derived from alpha1-positive cells and grown in long-term marrow culture indicated that these cells were similar to stromal cells from primary cultures. We also observed early upregulation of alpha 4 and alpha 2 integrin subunits in cultures derived from alpha1-positive cells with maximal expression by day 10 (26 and 51%, respectively) preceding a gradual decline to low to nil values at day 30 (4.5 and 12%). These data indicate that alpha 1 integrin subunit is a marker for both mature stromal cells and stromal precursors, while alpha 2 and alpha 4 integrin subunits are expressed primarily by immature cells.     

Interaction of pathogenic bacteria with rabbit appendix M cells: bacterial motility is a key feature in vivo

Rabbit appendix consists mainly of lymphoid follicles (LF) covered by M cells, the specialized antigen-sampling cells of the mucosal immune system, and surrounded by glandular epithelium. Until now, these M cells have been characterized morphologically and histologically by using cellular markers. Here, the adhesion and transport of pathogenic bacteria were investigated to assess the function of M cells of the appendix. We used the enteroinvasive motile Salmonella typhimurium and the rabbit enteropathogenic non-motile Escherichia coli RDEC-1, which are known to target specifically rabbit M cells of Peyer's patches (PPs). We found that S. typhimurium efficiently attached and was transported through appendix M cells in vivo. In contrast to S. typhimurium, RDEC-1 targeted M cells only ex vivo, when bacteria were allowed to have direct contact with the surface of the follicle. The difference in interaction of the two bacteria with appendix M cells led us to investigate whether this could be correlated with the lack of motility of RDEC-1. We used an aflagellate mutant of S. typhimurium and found that it had the same infection phenotype as RDEC-1. Gene complementation restored the efficiency of infection to that of S. typhimurium wild-type strain. In conclusion, we show that M cells of the appendix display features of the canonical M cells of PP, since they efficiently sample luminal pathogenic bacteria. However, due to the morphology of the appendix, motile bacteria appear to be more potent in their interactions with appendix M cells.     

The distribution of myofibroblasts and CD34-positive stromal cells in normal renal pelvis and ureter and their cancers

In this article, we examined the distribution of myofibroblasts and CD34-positive stromal cells in normal renal pelvis and ureter and their cancers using immunohistochemistry. Eighteen tumors and normal tissues apart from the main tumor were examined. In the wall of normal renal pelvis and ureter, no myofibroblasts were observed through all layers, but CD34-positive stromal cells were observed in the deep area of lamina propria, muscular layer and adventitia. In the stroma of renal pelvic and ureteral cancers, myofibroblasts were distributed in fifteen tumors and were absent in three tumors. All three tumors containing no myofibroblasts in the stroma were non-invasive type and all invasive cancers contained myofibroblasts in the stroma. CD34-positive stromal cells were consistently absent in the stroma of cancers, irrespective of the invasiveness. Finally, myofibroblasts are major stromal components in renal pelvic and ureteral cancers, particularly in invasive cancers, and CD34-positive stromal cells are consistently absent or lost in the stroma of their cancers. These findings suggest that the invasion of renal pelvic and ureteral cancers may cause the phenotypic change of stromal cells.     

Ocular neovascularization caused by herpes simplex virus type 1 infection results from breakdown of binding between vascular endothelial growth factor A and its soluble receptor

The normal cornea is transparent, which is essential for normal vision, and although the angiogenic factor vascular endothelial growth factor A (VEGF-A) is present in the cornea, its angiogenic activity is impeded by being bound to a soluble form of the VEGF receptor-1 (sVR-1). This report investigates the effect on the balance between VEGF-A and sVR-1 that occurs after ocular infection with HSV, which causes prominent neovascularization, an essential step in the pathogenesis of the vision-impairing lesion, stromal keratitis. We demonstrate that HSV-1 infection causes increased production of VEGF-A but reduces sVR-1 levels, resulting in an imbalance of VEGF-A and sVR-1 levels in ocular tissues. Moreover, the sVR-1 protein made was degraded by the metalloproteinase (MMP) enzymes MMP-2, -7, and -9 produced by infiltrating inflammatory cells that were principally neutrophils. Inhibition of neutrophils, inhibition of sVR-1 breakdown with the MMP inhibitor marimastat, and the provision of exogenous recombinant sVR-1 protein all resulted in reduced angiogenesis. Our results make the novel observation that ocular neovascularization resulting from HSV infection involves a change in the balance between VEGF-A and its soluble inhibitory receptor. Future therapies aimed to increase the production and activity of sVR-1 protein could benefit the management of stromal keratitis, an important cause of human blindness.     

Indications for operation in suspected appendicitis and incidence of perforation.

OBJECTIVE--To clarify poorly understood epidemiological features of appendicitis. DESIGN--Retrospective study of consecutive cases from a defined population and analysis of data from published studies. SETTING--County of Jönköping, Sweden. 3029 patients who underwent operation in 1984-9 and 4717 patients from the county town who underwent operation in 1970-89, all for suspected appendicitis, plus 48,426 cases from six reported studies. MAIN OUTCOME MEASURES--Incidences specific for age and sex and temporal trends of perforating and non-perforating appendicitis and removal of a normal appendix. Associations between diagnostic accuracy, rate of perforation, and incidences of removal of a normal appendix and of perforating and non-perforating appendicitis. RESULTS--The incidence of appendicitis was 116/100,000 inhabitants. Appendicitis was more common in male patients. The incidence of perforating appendicitis was independent of age, stable over time, and uninfluenced by the rate of laparotomy, whereas the incidence of non-perforating appendicitis was age dependent, decreasing over time, and related to the diagnostic accuracy and rate of removal of a normal appendix. CONCLUSIONS--Perforating and non-perforating appendicitis seem to be separate entities, and appendicitis that resolves spontaneously is common. This may have important implications for managing suspected appendicitis.     

The presence of cytokine (IL-8, IL-1alpha,IL-1beta)-producing cells in inflamed gingival tissue from a patient manifesting Papillon-Lefevre syndrome(PLS)

The point of this study was to examine the presence or absence of cytokine-positive cells by means of immunohistochemical methods in the samples of inflamed gingival tissues obtained from an 11-year-old girl with Papillon-Lefevre syndrome (PLS). Interleukin-8 (IL-8)-positive cells were found to be present. In addition, IL-1alpha-and IL-1beta-positive cells were detected. No dysfunction in the phagocytosis and the bacterial killing of peripheral blood polymorphonuclear neutrophils (PMNs) was observed in this patient. Our findings suggest that these cytokines may be members responsible for modulating the process of rapidly progressive periodontitis for patient with PLS.