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Muscarinic action of acetylcholine was demonstrated in the human isolated appendix. Histamine-induced contractions seemed to the mediated by H1 receptors. Nicotine and DMPP-induced contractions were mediated through their action on ganglion cells. Experiments with adrenergic drugs suggested the presence of beta receptors.
On the occasion of diagnosing one case of primitive malignant lymphoma of the appendix at the Institute of Surgical Semiology, University of Pavia, the authors discuss a number of aspects of the clinical picture, anatomopathology, and therapeutic approach to this rare malignancy.
Intussusception of the vermiform appendix is reported in a frequency of 0.01%. Different aetiologic factors are implicated, a directed hyperperistalsis against intraluminal obstruction is thought to be the pathogenetic mechanism. There is a lack of typical symptoms, very often appendicitis or caecal tumor is diagnosed. Concomitant inflammation renders recognition more difficult. The caecum must be resected if a malignant tumour cannot be ruled out. Appendectomy is performed in definite findings. Our case report may remind of this uncommon occurrence.
The adenocarcinoma of the vermiform appendix is most frequently discovered at the pathological examination, which causes the problem of a second operation. Our study was done on 145 patients and compares survival according to the attitude taken by the surgeon. It seems that the most favorite treatment is a precocious right hemicolectomy.
The influence of medroxyprogesterone acetate (MPA) on lymphoid tissue of rabbit appendix was investigated. The agent caused a uniform depletion of lymphoid cells, which confirmed the immunodepressive properties of the drug. Other findings suggested a corticoid action of the agent and a possible anticellular activity, interfering with nucleic acid synthesis of proliferating cells.
A preliminary study with various pharmacological agents revealed the presence of contractile muscarinic and H1-histamine receptors as well as inhibitory alpha- and beta-adrenoceptors and purinoceptors in rat caecum-appendix. Histamine also produced indirect actions mediated through the release of catecholamines. 5-Hydroxytryptamine produced variable response, the contractile response was mediated through 5-HT receptors and the relaxant response through the release of catecholamines.
Mural tumours of the colon are rare and may be difficult to distinguish from extrinsic lesions. We report a case of an apparent intramural sigmoid tumour due to a mucocele of the appendix and discuss the radiological diagnosis of mural tumours of the large bowel.
Human appendices from 3 to 12 years old children were studied by light and electron microscopy. Three morphological zones were determined: sub-epithelial (or lymphoid lamina propria), parafollicular, and follicular. The fine structure of these regions has been studied and discussed with regard to the thymus-dependent and thymus-independent regions of other lymphoid organs. Two types of lymphocytes, 'light' and 'dark', and intermediate forms, were also found. The light ones are the more abundant in the epithelium and within the parafollicular post-capillary venules; they form groups or clusters between epithelial cells, becoming like blast cells and possibly maturing into plasma cells in the sub-epithelial region. Whether light lymphocytes are T or B or both is discussed. The general conclusion is that the human appendix, at least in children, has the characteristics of a well-developed lymphoid organ, suggesting that it has important immunological functions.
We have histochemically evaluated the LAP, AP and ANE activities of the human appendix in 100 surgical specimens. The mucosa has been particularly investigated for its different aspects during inflammatory conditions. Two main facts have been ascertained: the subepithelial location of macrophages, and the AP and ANE activities of two groups of cells in the germinal centers. Subepithelial macrophages show conspicuous AP activity that correlates with the degree of inflammatory response and of exposure to luminal antigens. In the germinal centers, AP and ANE activities disclose two further groups of positive cells, probably the same cells reacting to both technics. One group is rooted to the core of the germinal center; the other to the intermediate area between the germinal center and the follicular mantle.
To test earlier theories on the subject, extraepithelial enterochromaffin (EEEC) cells were sought in the mucosa of 500 appendixes and in the solid axial cores of 283 others whose lumina were obliterated over part or all of their lengths. The EEEC cells were lying free in the lamina propria of 53% of the specimens with intact lumina and in the axial cores of 49% of the obliterated specimens. In both locations they were invariably accompanied by Schwann cells and neurites, which were often present in markedly increased numbers. Therefore, because they occur so frequently in nonepithelial locations, enterochromaffin cells can no longer be considered as exclusively epithelial. Their close association with Schwann cells and neurites suggests that they may have some sort of neural function.
The fine structure of a neuroendocrine complex within the lamina propria of the human appendix is described. This complex contains four types of neurosecretory cells, occasional neurons, Schwann cells, and numerous nerve processes, including axons with varicose swellings. Few of the axons form true synapses, but many make some junctional contact with the neurosecretory cells and with other nerve processes. From the morphology of their vesicles, most of the nerve fibers appear to belong to the peptidergic component of the enteric nervous system. The mucosal neuroendocrine complex appears to be an integral part of the mucosal nervous plexus.
5 cases of carcinoid of the appendix discovered during 1094 appendectomies are described. Neither carcinoid syndrome or local metastasis was observed in any of the patients. The importance of the histological examination of all appendices removed is emphasised. Where there is no metastasis, radical surgery is appropriate. The prognosis is excellent but patients should be monitored by the measurement of 5HIIA in the urine.
The examination of the caecum of two groups of cynomolgus and rhesus monkeys, two orang-utans and a chimpanzee, as well as an extensive review of the available literature, confirmed that the length of the caecum, relative to that of the colon, decreased as the position of the species in the primate scale rose. Although absent in prosimians and New World monkeys, there was evidence that the appendix vermiformis began to develop in certain Old World monkeys and became fully developed in the anthropoid apes, showing that, far from being a vestigial organ, it has actually developed progressively in primates.
Reference is made to two cases of mucocele of the appendix in a brief discussion of this form, its frequency, and the difficulties associated with its preoperative diagnosis. Mention is also made of the problems arising in the differentiation of benign and malignant mucoceles. Some conclusions are drawn with regard to treatment.
Description of a case of malacoplakia involving the ascending colon and appendix in a 11-year-old boy with history of severe diarrhea. The lesions were studied by light and electron microscopy. They were composed of proliferation of histiocytes with the typical cytoplasmic inclusions known as Michaelis-Gutmann bodies. The authors comment the pathogenesis of malakoplakia pointing out its rarity in infancy and in the intestine. They also review the literature and stress the importance of the development of malakoplakia in severe enterocolitis.
Effects of amethopterin (MTX) on lymphoid tissue of rabbit appendix have been evaluated. The drug caused an evident depletion of lymphoid cells. This finding suggested the relevance of cytotoxicity in the mechanism of immune suppression. Discontinuation of drug treatment demonstrated a tendency toward the reorganization of the lymphoid tissue.
A case of mucocele of the appendix, uncovered during an abdominal exploration on a tentative diagnosis of incipient inguinal hernia, is reported. The small mucocele is unlikely to have been responsible for the recorded symptoms and signs.
The authors tried to establish the most frequents anatomo-radiological patterns of the irrigation on the vermiform appendix. The search was done in one hundred cases they found six different patterns of arterial irrigation.