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PubMed1976

B and T cells in lymphoid tissues of human appendix.

Human appendix lymphoid cells (HAL) react very strongly to stimulation with concanavalin A, strongly to stimulation with phytohaemagglutinin, and weakly but definitely to stimulation with lipopolysaccharide. From the results of rosette formation assay, cytotoxicity tests with anti-T cell antiserum or anti-B cell antiserum, cell surface or intracellular immunoglobulin staining with fluorescein-conjugated rabbit anti-Fab of human immunoglobulin serum, and plaque-forming cell (PFC) assay, it was concluded that human appendix lymphoid tissue is a B cell pool but includes T cells. However, both direct and indirect PFC could not be significantly demonstrated against sheep red blood cells in a 5-day HAL culture.

Amphotericin B↗
PubMed1988

Appendicovesical fistula associated with neuroma of the appendix.

A new case of appendicovesical fistula is reported. Usually a known cause is ulcerative colitis, morbus Crohn, malignancy of the appendix or as complication to perforated appendicitis, but in the described case there was no history of such previous illness. The only pathological finding was the presence of an abundant amount of nervous tissue in the appendix. It is concluded that a history of pneumaturia and/or recurrent urinary-tract infections must rise the suspicion of the presence of a fistula between the small or large intestine and the bladder.

Appendiceal Neoplasms↗
PubMed1992

The appendix as a continence mechanism.

Although we have progressed very well in creating large capacity, low pressure reservoirs, the construction of a simple and reliable continent outlet still remains a problem. The appendix vermiformis serves well as a continence mechanism for either the bladder or intestinal reservoirs for urine. The different surgical techniques described in the literature are reviewed and discussed in this context. Moreover, we report on our clinical and experimental results of using the appendix during the Mainz pouch procedure for continent urinary diversion.

Adolescent↗
PubMed1973

Some characteristics of the rabbit vermiform appendix as a secreting organ.

It has been confirmed that the rabbit vermiform appendix secretes spontaneously at a relatively rapid rate (1-12 ml.h(-1); 1.4+/-0.24 mul.min(-1).cm(-2)). The electrolyte composition is similar to that of ileal fluids and independent of the secretory rate. The transmural potential difference is about 12 mV, mucosa negative. Of the major electrolytes, only HCO(3) (-) is secreted grossly against its electrochemical potential difference. This finding plus the low hydraulic (or osmotic) permeability (L(p)) and high secretory pressures of the organ strongly suggest that the secretion is an active one. The passive permeability to Na(+) and Cl(-) appears to be, at most, somewhat less than for small bowel. Permeability to mannitol was estimated at 2.5 x 10(-7) cm.s(-1). On the basis of reasonable assumptions and results with luminal test solutions of differing osmolarities, it was concluded that (a) the L(p) of the appendiceal epithelium is in the lower range of values reported for small bowel and colon; (b) the L(p) is higher for osmotic absorption than for osmotic secretion; and (c) the rate of spontaneous secretion is insensitive to luminal anisotonicity over a wide range of values. But sufficiently hypotonic solutions can reverse net secretion to net absorption, more by inhibiting spontaneous secretion than increasing osmotic absorption. The rabbit vermiform appendix appears to be a useful model for the elucidation of intestinal secretory processes.

Animals↗
PubMed2004

Appearance of a type B duplex appendix on barium enema.

Anomalies of the appendix are rare and are usually found in the adult population as an incidental finding during the course of surgery. We describe the appearances of a Type B duplicated appendix demonstrated on a barium enema for the first time. A review of the literature is presented with a discussion of different forms of duplicated appendices and the clinical significance of this finding.

Aged↗
PubMed2003

Histology of vermiform appendix-like organ in slow loris.

The vermiform appendix-like organ (VALO) of the slow loris was investigated for its histology and immunohistochemical characteristics. The VALO has a much thinner wall with flat folded mucosa and shallower crypts than the cecal mucosa, while cellular components and population of the mucosa were similar to those of the cecum. No coalescent lymph nodules were seen in the submucosa. Immunohistochemically 5-HT-positive cells in the crypts and CD3- and CD8-positive lymphocytes in the lymph nodules were shown in the VALO as well as in the cecum. These findings suggest that the VALO is a low-differentiated vermiform appendix of the slow loris.

Animals↗
PubMed2001

Mycobacterial spindle cell pseudotumor of the appendix vermiformis in a patient with aids.

Mycobacterial pseudotumor (MP) is a rare pathologic presentation of both Mycobacterium tuberculosis and non-tuberculous mycobacterial disease, hitherto reported to occur only in immunosuppressed patients with or without human immunodeficiency virus infection. This lesion shares close pathologic resemblance to certain mesenchymal neoplasms, particularly Kaposi's sarcoma (KS), from which it must be properly differentiated due to distinct prognosis and therapy. We report a case of MP obliterating the lumen of the appendix vermiformis in a 34-year-old patient who died of complications of AIDS at our hospital in Rio de Janeiro. A total of 24 cases of MP (including our patient) have been described in the literature. MP has been found especially in lymph nodes, but extranodal lesions have been described in the skin, spleen, lung, bone marrow, brain and, in our patient, the appendix vermiformis. We offer a review of the other 23 published case reports of MP in both HIV-infected and uninfected patients and discuss the pathologic features that differentiate MP from KS.

AIDS-Related Opportunistic Infections↗
PubMed1988

Blood vascular organization of the human appendix: a scanning electron microscopic study of corrosion casts.

Blood vascular beds of the human appendix were reproduced with a methacrylate casting medium and observed with a scanning electron microscope. The appendix received some small afferent arterial branches of the appendicular artery. These small arterial branches pierced the muscular layer and reached the submucosal plexus. Small arterioles arising from this plexus, climbed the mucosa and formed honeycomb-like capillary meshes at the luminal surface level. These capillaries were drained by the collecting veins, which descended the mucosa and joined the submucosal plexus. The large efferent veins arising from the submucosal plexus passed through the muscular layer and continued with the appendicular vein. In the mucosal and submucosal layers, several spherical basket-like casts of the germinal center (lymphoid follicle) were seen. In the parafollicular region (primary follicle), casts of postcapillary venules with prominent surface undulations were relatively frequently observed.

Adult↗
PubMed1983

Functional histology of appendix.

The appendix is a prominent example of gut associated lymphoepithelial tissue, whose function is to react to the wide variety of antigens present in the gastrointestinal tract. It is composed of a large number of repeating units, the lymphoid follicles, each of which is divided into an apical dome, a large basal nodule with a germinal center, and laterally extending thymus dependent areas. The dome epithelium consists mainly of columnar absorptive cells and of specialized follicle associated epithelial (FAE) cells which are efficient at transporting material from the lumen to the underlying lymphoid tissue, and may also transport macromolecules from the lymphoid follicle into the lumen. The dome epithelium normally has large numbers of lymphocytes within it, as well as smaller numbers of macrophages and plasma cells. Macrophages, and perhaps FAE cells, are capable of processing and presenting antigens to reactive lymphocytes. Lymphocyte proliferation and differentiation in response to antigenic stimulation begins in the lymphoid follicles, but most of the lymphocytes leave by the lymphatics, migrate through lymph nodes and spleen, frequently to complete differentiation into IgA-secreting plasma cells in the lamina propria of mucosal surfaces. Normal function of appendix probably helps suppress potentially destructive humoral antibody responses while promoting local immunity.

Animals↗
PubMed1985

Intercellular spaces in the lymph nodule associated epithelium of the rabbit Peyer's patch and appendix.

Intercellular spaces in the epithelium of the rabbit Peyer's patch and appendix were examined by scanning and transmission electron microscopy to elucidate their three-dimensional structure and their relationship to the reticular spaces in the underlying lymph nodule. Two types of intercellular spaces were distinguished: regularly arranged tubular channels and irregularly winding tunnels. The tubular channels were observed around normal enterocytes on the villi or internodular folds and apical portions of nodule domes. The channel spaces were lined with a successive arrangement of belt-like intercrestal surfaces of prismatic enterocytes and variously sized processes on the crests. The processes adjoining opposed crests formed a ladder-like structure or pectinate septa between neighboring channels. The irregularly winding tunnels were formed among processes of irregularly shaped cells corresponding to FAE cells (Bockman and Cooper, 1973) or M cells (Owen and Jones, 1974) in the nodule associated epithelium. In the appendix, the tunnels were frequently organized into two-story spaces, the adlumenal and basal spaces, which were incompletely separated by cytoplasmic processes. These tunnels continued by pores in the basement membrane to the reticular spaces in the underlying lymph nodules. Furthermore, the tunnels and the basement membrane pores constantly contained single or grouped free cells or their processes. The findings in the present study suggest that the tubular channels are intraepithelial compartments for the absorption of nutrients and fluid, and the irregular tunnels are an intraepithelial network of spaces for the housing of lymphoid cells coming from the underlying lymph nodule.

Animals↗
PubMed1977

Gas-filled appendix: lack of diagnostic specificity.

Three patients with a gas-filled appendix in association with acute abdominal symptoms are described. In each case the gas-filled appendix was located in the right lower quadrant. None of the patients had appendicitis. It is emphasized that this combination of findings is not neccessarily diagnostic of appendicitis. Clinical evaluation is important in assessing the significance of this sign.

Abdomen↗
PubMed1987

Natural history of the obstructed rabbit appendix: observations with radiography, sonography, and CT.

Chronic (1-3 months' duration) appendiceal obstruction was induced in 11 rabbits to assess the pathologic consequences and to study the associated radiologic, sonographic, and CT findings. Three pathologic/radiologic groups resulted with approximately equal frequency. In group A, the abscess was characterized by inflammatory cells in the lumen and wall of the appendix without mucin production. Calcification was shown radiographically, and sonography showed an anechoic or complex pattern. Group B, the "mixed response," was characterized by an intact hyperplastic mucosa, mucin secretion, and inflammatory debris in the lumen. Occasional calcification was present radiographically, and sonography showed a complex or hypoechoic pattern. In group C, true mucoceles had an intact hyperplastic mucosa, a mucin-filled lumen, and minimal inflammation. These were anechoic on sonography except for mobile foci of inflammatory debris. Chronic obstruction of the appendix results in a spectrum of pathologic responses with varying degrees of either inflammation and mucosal destruction or mucosal hyperplasia and mucin secretion. An abscess results when infection overwhelms the host's inflammatory responses. If the bacteria are destroyed by these defenses, a mucocele forms. An intermediate situation occurs when there is a mixed response with chronic inflammatory changes and an intact mucosa. This finding supports the existence of chronic appendicitis in humans.

Animals↗
PubMed1977

Pathological changes in the appendix: a review of 1000 cases.

The pathological changes occurring in a series of 1000 consecutive appendicectomies are reviewed. Normal appendix was diagnosed in 14% of cases, while 561 (56%) exhibited acute appendicitis; 53 (5%) had chronic inflammatory infiltrate associated with obliteration of the lumen of the tip of the appendix. Epithelial abnormalities included carcinoid tumours (1.4%), and primary appendiceal adenocarcinoma (1 case). There were a large variety of other abnormalities found and each one is briefly described.

Acute Disease↗
PubMed1992

Age, site and distribution of subepithelial neurosecretory cells in the appendix.

The appearance of subepithelial neurosecretory cells (SNC) was investigated by studying completely sampled appendices of 50 children, adolescents and adults. The cells were demonstrated using lead hematoxylin, a selective stain for neurosecretory cells. Additional routinely sampled specimens were also studied for comparison. In children up to the age of 9 yrs only occasional SNC were found. After this age, however, SNC were present in most appendices and in greater numbers. The majority of SNC were located in the distal portion of the appendix, with only small numbers of these cells being present in the proximal segment. Occasional SNC-like cells were identified in the appendiceal submucosa in all regions of the appendix at all ages. This lends support to the hypothesis that a correlation exists between the presence of increased numbers of SNC, patient age and the site distribution of both acute appendicitis and appendiceal carcinoid tumors.

Adolescent↗
PubMed2005

Mucocele of the appendix: an unusual cause of lower abdominal pain in a patient with ulcerative colitis. A case report and review of literature.

The authors report the case of a 60-year-old male patient. In November 2001 he developed intestinal symptoms of bloody diarrhea and abdominal pain. Colononoscopy and biopsy established the diagnosis of ulcerative colitis (proctosigmoiditis). The disease activity was moderate at the beginning. No significant laboratory alterations were found (including CEA, CA19-9), and mesalazine was started orally. He was in remission until November 2003, when he was admitted to our Outpatient Clinic for upper and right lower abdominal pain and bloody diarrhea. Colonoscopy found proctosigmoiditis with a moderate activity, gastroscopy revealed chronic gastritis, laboratory data was normal. Treatment was amended with mesalazine clysma and methylprednisolone (16 mg) orally. Symptoms ameliorated; however, right lower abdominal pain persisted. US and CT examination demonstrated a pericecal cystic mass (11 cm x 3.5 cm). At first pericecal abscess was suspected, as the previous US examination (6 mo earlier) had revealed normal findings. Fine needle aspiration was performed. Cytology confirmed the diagnosis of mucocele. The patient underwent partial cecum resection and extirpation of the mucocele. He recovered well and the final histology revealed a cystadenoma of the appendix. Follow up was started. The patient is now free of symptoms. Although primary adenocarcinoma of the appendix is uncommon, the authors emphasize that preoperative diagnosis of an underlying malignancy in a mucocele is important for patient management; however, it is difficult on imaging studies.

Abdominal Pain↗
PubMed2002

[A case of stone formation in the Mainz pouch using appendix as the efferent limb: a case report].

A large calculus (6.0 x 4.5 x 7.0 cm sized) in the continent urinary pouch was detected incidentally by computed tomography in a 7-year-old man with a gall bladder stone. He underwent a total cystectomy and Mainz pouch formation using appendix as the efferent limb for bladder cancer 7 years ago. Urine culture showed Proteus mirabilis and Escherichia coli, and urine pH was 8.5. The stone was removed successfully through a pouchotomy and composed mainly of struvite. The stone analysis was MAP; 88% and CaCO3; 12%. Convalescence was uneventful. This is the first case of in Mainz pouch using appendix as the efferent limb.

Aged↗
PubMed1984

Ultrasonic and computed tomographic features of mucocele of the appendix.

The ultrasonic features in three cases and computed tomographic (CT) findings in one case of mucocele of the appendix are presented. This entity appeared cystic on sonography and may have high-intensity echoes within it. The wall was not thickened and did not contain calcification, unlike previous descriptions. On CT, the mass was of soft tissue density, while previously, it had been described as cystic. Although mucocele of the appendix has a more variable appearance on sonography and CT than previously reported, a correct preoperative diagnosis can be made in most cases. Barium enema examination or calcification in the wall or in the mass itself may be necessary to distinguish this entity from lymphoma if the lesion is of soft tissue density on CT.

Aged↗
PubMed1997

[The absorbing peripheral lymphatic apparatus and blood vessels of the vermiform appendix: the 3-dimensional and ultrastructural aspects].

We studied the lymphatic angiotectonics of the vermiform appendix of the rabbit, using direct injection of Neoprene latex, electron microscopy and three-dimensional models. We observed that the vermiform appendix is made of absorbing lymphatic vessels distributed among the tubular glands of the tunica mucosa. Moreover, these absorbing lymphatic vessels continue through the straight vessels into a vast, basket-like lymphatic network, which envelopes the medium and basal portions of each single lymphoid follicle. In addition, the vessels of this network reach the submucosal network, whose vessels are peculiar in shape and size. The submucosal network, in turn, drains the lymph through the small caliber intramuscular vessels in the valved subserous precollector lymphatic vessels. We also highlighted the ultrastructural characteristics of the absorbing lymphatic vessels, which completely lack openings at the contacts between the adjacent endothelial cells, which were always joined by specialized junction complexes. Moreover, we reported the presence of intraendothelial channels which we affirm are dynamic morphologic entities, through which lymphocyte migration from the peri-interfollicular lymphoid tissue inside the absorbing lymphatic vessels takes place.

Animals↗