Changes in the length and diameter of the normal appendix throughout childhood.

BACKGROUND/AIM: It has been proposed that the narrow diameter of the appendix is important in providing a 'safe zone' for commensal intestinal flora, while the length of the appendix can be variable. This study aimed to investigate the relationship between appendiceal length, diameter and age, in children under the age of eighteen years, to determine if the appendix changes in size with age. METHODS: The histological records of all cases of children undergoing appendicectomy at the Royal Children's Hospital (Melbourne) between 2009 and 2011 were retrospectively reviewed. Participants were excluded on the basis of histological evidence of acute inflammation, and data on the diameter and length of the appendix were collected from 210 children, aged zero to seventeen years. RESULTS: Data were stratified by age for analysis into ≤ 3 years, >3 and ≤ 9, >9 and ≤ 13 and >13 years. Mean diameters per group were 3.7 (± 1.3), 6.3 (± 1.2), 6.7 (± 1.6) and 6.9 (± 1.6) millimetres respectively. Mean lengths per group were 39.7 (± 16.1), 66.3 (± 15.3), 63.7 (± 21.3) and 68.8 (± 18.2) millimetres. Both diameter and length were higher in the older age groups, compared with the ≤ 3 year olds (p < 0.001). A positive correlation was seen between age and appendix diameter (R = 0.5, p < 0.001) and length (R = 0.3, p=0.03) in the ≤ 3 group only. Mean diameter and length values did not differ significantly between groups aged > 3 years old. CONCLUSION: This study showed that following an initial growth period during early infancy up to about 3 years, the appendix achieves its adult proportions and does not continue to grow throughout childhood.

[Sonographic detection of normal appendix in children and adolescents]. / Sonografische Darstellung der normalen Appendix im Kindes--und Jugendalter.

PURPOSE: The frequency of depiction of the normal appendix by real time B-mode sonography in children was evaluated in a prospective study. MATERIALS AND METHODS: In 274 consecutive patients, age one to nineteen, without abdominal pain, depiction of the normal appendix was attempted using a 5-12 MHz linear array transducer. The ultrasound examination was performed using the graded compression technique according to the description of Puylaert. Depiction of the normal appendix was graded as a) complete, b) partial and c) unable to be depicted. In addition the position and diameter of the appendix, the examination time and the image quality were documented. RESULTS: The appendix was depicted completely in 74% of all patients and partially in 10%. In the age group of one to nine years, complete depiction was possible in 86% of the cases. The most common position with 87% was caudal and mediocaudal, 11% of the appendices were located retrocecal and 2% had a cranioventral position. The mean diameter of the appendices was 4.1 mm (range 3-7 mm). The mean examination time to depict the normal appendix completely was 3.7 min compared to 7.6 min in partial or incompletely depicted cases. In most cases in which complete depiction of the appendix was possible, the image quality was excellent. CONCLUSION: Since the normal appendix in children can be reliably depicted by experienced examiners using high-resolution linear transducers, ultrasound is suitable as a reliable imaging modality for excluding acute appendicitis in children.

A neonate with an intact congenital umbilical appendix: an alternative theory on the etiology of the appendico-umbilical fistula.

Neonatal umbilical anomalies usually represent remains of the vitelline duct or the allantois. We describe a case of an umbilical appendix in a neonate. The vermiform appendix was found to be positioned in the umbilical cord. In a brief literature review we found eight other reports concerning umbilical appendices. In this article we describe a possible embryological explanation for the development of an umbilical appendix, and discuss whether or not the appendiceal umbilical fistulae reported are congenital or iatrogenic. The possible association between an umbilical appendix and different forms of malpositioning and rotation of the gut is also discussed. Protrusion of the neonatal appendix into the umbilical cord represents a different entity of congenital anomalies. It is important to realize that, in the case of an unrecognized umbilical appendix, medical procedures (e.g., canulation or clamping of the umbilicus) may produce an iatrogenic appendico-umbilical fistula. Careful inspection and palpation of the umbilical cord prior to these procedures may prevent a fistula being created. Furthermore, because the possible association between umbilical appendices and different kinds of malpositioning of the gut is so far not wholly elucidated, we recommend further (radiological) investigation in each case of an umbilical appendix. Correct positioning of the bowel needs to be confirmed in order to rule out possible future complications.

Isolation of mesenchymal stem cells from human vermiform appendix.

BACKGROUND: Recent findings have shown that pluripotent stem cells exist in areas outside the bone marrow (BM). Moreover, it has been demonstrated that the appendix is important for the development of mucosal gut immunity, and hematopoietic progenitors have been isolated from animal and human appendices. MATERIALS AND METHODS: Non-inflamed appendices removed during laparotomy were processed and cultured until the appearance of adherent cells. Differentiations (performed under osteogenic, adipogenic, and myogenic conditions) were confirmed by immunohistochemistry and cytochemistry. Polymerase chain reaction and cytofluorimetric analyses were performed to evidence the presence of genes and protein specific lineages in appendix-derived mesenchymal stem cells (ADMCs). RESULTS: ADMCs were present in non-inflamed appendices. ADMCs under osteogenic conditions differentiated in osteoblasts and showed increased alkaline phosphatase expression; at the gene level, we observed the expression of Core binding factor alpha 1 (Cbfa1) and osteocalcin in osteogenic induced ADMCs. Under adipogenic conditions, lipidic drops in the cytoplasm, expression of lipoprotein lipase (LpL), and peroxisome proliferator-activated receptor gamma were observed; under myogenic conditions, myotubes expressing muscle specific proteins like desmin were formed. Myogenic regulatory factor 4 and MyoD were selectively induced in the ADMCs under myogenic conditions. CONCLUSIONS: This study shows for the first time that mesenchymal stem cells can be isolated from normal appendices obtained from a pediatric and adult age group (0-18 years of age). This finding not only may further knowledge of the maturation of the intestinal immunesystem but also could indicate a new physiological role of the human vermiform appendix.

The appendix functions as a mammalian bursal equivalent in the developing rabbit.

In this paper we present genomic DNA sequence and histological evidence that the appendix is a site of diversification of the rabbit's primary antibody repertoire. By 6 weeks after birth, the B cell follicular regions of the rabbit appendix and the distribution of the resident lymphoid cells bear a strong morphological resemblance to similar regions within two primary lymphoid tissues, the chicken bursa and the sheep ileal Peyer's patch. However, similarities between the rabbit appendix, chicken bursa and sheep ileal Peyer's patch end as these animals reach adulthood. The rabbit appendix undergoes morphological and cellular distribution changes as it matures taking on the appearance of a secondary lymphoid tissue, while the sheep ileal Peyer's patch and the chicken bursa both involute. We determined DNA sequences of PCR amplified rearranged variable region genes from germinal center B cells of 6 week old rabbits isolated from several different appendix dark zones and light zones. There was a trend toward a higher degree of diversification from the germ-line VH gene DNA sequence in dark zones than light zones. It is likely that both gene conversion and somatic hypermutation are responsible for the nucleotide changes we observed. Our findings suggest that the rabbit appendix functions as a mammalian bursal equivalent early in development. As the rabbit matures, the appendix appears to evolve into a secondary lymphoid tissue resembling secondary GALT in appearance and possibly in function.

Development of dome epithelium in gut-associated lymphoid tissues: association of IgA with M cells.

The dome epithelium (DE), which covers gut-associated lymphoid tissues (GALT) and provides both a protective barrier over lymphoid follicles and a route for antigen uptake from the gut, develops in rabbit appendix (caecum) during the first week of neonatal life. To determine if secretory immunoglobulins from maternal milk interact with this developing tissue, their interrelationships in neonatal rabbit appendix were examined by use of immunocytochemical techniques. The glycoprotein, secretory component, was not produced by neonatal rabbits less than 15 days old, since neither the membranous nor the free, secreted forms of maternal secretory component were associated with villi or DE of neonates. Immunoglobulin A (IgA), but neither IgG nor IgM, were noted on DE by light microscopy, even though IgG was abundant in the villus lamina propria and vascular spaces. The epithelial IgA was distributed, in a patchy pattern, across the upper dome surface of some two-day-old, and all five-and ten-day old nursing animals, but IgA was not on DE of rabbits prevented from nursing. Immuno-electron microscopy of appendix from nursed rabbits revealed IgA directly over the apical surface of M cells, where it formed a continuous, thick coating without binding to adjacent immature absorptive cells; it was also within apical vacuoles of M cell cytoplasm. The distribution of IgA on the DE of rabbit appendices indicated that in differentiating GALT, maternal IgA reacted preferentially with M cells or pre-M cells, leading to speculation concerning a role for IgA in the development of GALT and in establishment of mucosal immune responses in neonates.

Development of the rabbit appendix. I. Electron-microscopic observations.

The progressive lymphoepithelial development of the rabbit appendix was examined by light and electron microscopy. At 5 days postnatally, the appendix wall primitively resembles the mature organ but lacks both the discrete lymphoid organization and most cell types. The dome appears to be the first recipient of lymphoid cells. By 18 days the lymphoid nodule has become compartmentalized and lymphoid. The epithelium, although not fully developed, is in contact with the lymphocytes of the dome. The 5-week-old appendix has all the lymphoepithelial components of the adult but lacks the size of the mature organ. At all ages reported, plasma cells and dendritic cells are absent. Bacteria, thought to be essential to appendical lymphoid development, are not apparent at 5 or 18 days. The features common to central or peripheral lymphoid tissues are discussed.

The normal and abnormal development of the appendix. A radiographic assessment.

Radiographic examinations of the colon in the adult demonstrate a wide variety of contours of the interior cecal segment and appendix. These findings are a result of the normal developmental process of the appendix which can be arbitrarily separated into four stages. Examples of appendiceal development arrested at different stages, as well as variations of the normal adult appendix, are explained and illustrated. Forms of primitive development and lack of development (agenesis) are discussed.