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Thirty-three patients with advanced, metastatic APUD tumors (islet cell, carcinoid, or medullary carcinomas of the thyroid) were treated with etoposide as a single agent. Of 29 evaluable patients, four (14%) had partial responses (95% confidence limits, 1%-26%). Toxic effects seen were those previously reported for etoposide as a single agent. Etoposide has activity in APUD tumors; further studies with this agent are indicated.
Neuroendocrine cells (NE) occurring in the pulmonary epithelium of the fishes Polypterus delhezi and P. ornatipinnis are studied by electron microscopy and by immunostaining for serotonin which is often present in such cells in the mammalian lung. With the electron microscopy NE are found to occur single, resting upon the basement membrane and forming a narrow cytoplasmic extension towards the air lumen. They contain dense-cored vesicles of 80-165 nm which form exocytotic profiles at the level of the basal membrane. An immunoreactivity for serotonin is demonstrated for the first time in the NE of these species. The role of this mediator may involve a paracrine or endocrine function as postulated for the respiratory neuroendocrine mammalian cells. NE of the species studied are considered similar to those found within the wall of lung airways in mammals and submammalian vertebrates. Although much immunocytochemical investigations remain to be executed, they may also be included in the APUD (or DNES) cell system.
In normal and L-Dopa treated rabbits and mice, combined immunochemical methods, photonic histological methods for endocrine cells and ultrastructural methods were used to elucidate ultrastructure and properties of somatostatin cells of the antral mucosa. In normal rabbits, immunoreactive cells giving no fluorescence with Falck's technic, they corresponded neither to serotonin cells nor gastrin cells; they were unreactive with Fontana, Hellerström-Hellmann, Sevier-Munger and Mac Conaill methods but very slightly stained with Grimelius methods. In L-Dopa treated animals somatostatin cells gave formaldehyde induced fluorescence (they were included in GIC cells, thus in Apud group), exhibited a good reaction with Grimelius and Sevier-Munger methods. In order to carry out the alternate semi-thin/thin section procedure (semi-thin sections for immunofluorescence or immunoenzymatic detection and serial thin sections counter-stained for conventional ultrastructure studies), immunological treatment were performed on M.F.F.--glutaraldehyde fixed small fragments of mucosa before inclusion in Epon 812 or, after inclusion, on semi-thin sections. We succeeded in identifying ultrastructurally somatostatin cells. They displayed round or ovoïd shaped secretory granules, and three constant typical structures: numerous microfilaments--light and homogenous granules, often seeming like lipids---granules made up by coarsely filamentous cores surrounded by a large empty halo. Somatostatin cells seemed different of X cells because of their predominant localisation in the antral mucosa (in the rabbit X cells were predominantly in the fundus) and because of the lack of nuclear microfilaments; they also seemed ultrastructuraly different of D1 cells.
In normal conditions, neuron-specific enolase (NSE) is histochemically demonstrable only in neurons and cells of the amine precursor uptake and decarboxylation (APUD) system. This has been found not to be true for neoplastic cells. Several types of CNS tumors, including glioblastoma, astrocytoma, oligodendroglioma, ependymoma, medulloblastoma, pineocytoma , meningioma, and choroid plexus papilloma, focally stained positively for NSE. Reactive astrocytes were also frequently positive. In the peripheral nervous system, neuroblastoma, ganglioneuroma, and paraganglioma stained positively for NSE. A number of non-APUD tumors were focally positive. These included schwannoma, carcinoma and fibroadenoma of the breast, renal cell carcinoma, giant cell tumor of the tendon sheath, and chordoma. Caution should be exercised in relying on the immunohistochemical demonstration of NSE as a diagnostic marker in those tumors that do not belong to the APUD cell system. It seems of little value as evidence of differentiation in CNS tumors.
An oat cell carcinoma occurring in the esophagus of a 62-year-old man is described. A strong argyrophilia of the oat cells together with the presence electron microscopically of neurosecretory type granules in their cytoplasm suggests a derivation of this tumor from the cells of the APUD series, and the tumor is diagnosed as apudoma. An aberrant columnar epithelium on the esophageal surface is presumed to be the source of its origin. A rapid postoperative course of the patient despite a rather circumscribed growth pattern of the primary tumor appears to characterize the clinical aspect of this case. An apparent accumulation of the cases with esophageal apudoma in Japan is discussed.
Somatostatin receptors have been described on the membrane of neoplastic cells derived from the APUD system and their expression has also been demonstrated on small cell lung cancer (SCLC) in vitro and in vivo. 21 patients with SCLC were studied using 111In-octreotide (111In-OCT) scintigraphy. Scintigraphic examinations were performed following intravenous (i.v.) injection of 111 MBq 111In-OCT with whole-body scintigraphy and planar scintigraphy of the thorax as well as the SPET technique. No short-term side effects were described following 111In-OCT administration. We studied the 111In-OCT biodistribution in 3 patients with serial scintigraphies at 1, 5 and 24 h. We used the 5 h as standard scanning time for the following 18 patients. The scintigraphic results were compared with those of other conventional diagnostic procedures. 111In-OCT detected 86% (48/56) of the lesions already known at the time of scintigraphy. It was positive in all 20 SCLC patients and negative in one lung adenocarcinoma. 111In-OCT showed high sensitivity for mediastinal metastases (94%) and good sensitivity for bone metastases (75%) and abdominal lymph node metastases (71%). 111In-OCT did not detect two liver metastases. 111In-OCT detected five unknown lesions which were confirmed by other diagnostic examinations. 111In-OCT was also effective in cancer patients with low levels of NSE. Our study shows that 111In-OCT scintigraphy is a reliable, non-invasive technique to detect primary SLCL and its locoregional or distant metastases. The clinical utility of receptor status characterisation obtained with 111In-OCT scintigraphy should be evaluated by means of an appropriate prospective study.
Using specific morphological and ultrastructural methods, the author demonstrated silver-absorptive cells in perisinusoidal areas in the liver parenchyma of guinea pigs. These cells exhibited some features characteristic of the endocrine cells of the diffuse APUD system. In anaphylactic and histamine shock their number decreased. These cells probably play a role in the pathogenesis of experimental bronchial asthma.
Light and electron microscopic studies were conducted on 10 humans who died of the different cardiac diseases; and 20 guinea pigs pineal glands. Pinealocytes or secretory cells of the pineal gland have morphological likeness with the APUD system cells. They have a well-developed endoplasmic reticulum, Golgi complex, mitochondrial component and in cytoplasm dense-core vesicles are discovered. However the pinealocytes have a neuron-like structure and they are not separate cells as apudocytes, but they are a principal component of the pineal parenchyma in which pinealocytes are in tight interactions with glia, blood vessels and nerve terminations. Analysis of morphological and functional similarity and difference between pinealocytes and apudocytes allows to consider pineal gland as an APUD organ. A circadian rhythmicity of some secretory vesicles in pinealocytes of the guinea pig has been established.
Rat gastric oxyntic glands contain argyrophil "enterochromaffin-like" endocrine cells that synthesize and store histamine and also have APUD ability--they can take up exogenous L-5-hydroxytryptophan (5-HTP), can decarboxylate it to 5-hydroxytryptamine (5-HT, serotonin) by the enzyme DOPA-decarboxylase, and can store the amine. Previous cytochemical studies suggested that these cells correspond to both the ECL and A-like cells, the two predominant endocrine cells identified by electron microscopy (EM) in rat oxyntic glands. In a recent study, however, we demonstrated that the ECL but not the A-like cell exhibited APUD ability when rat gastric mucosa was incubated with H3-5-HTP and studied by EM radioautography. The purpose of the present study was to identify by EM radioautography the histamine-synthesizing endocrine cells in the rat stomach. Pieces of rat (male Sprague-Dawley) gastric mucosa were incubated in organ culture with L-H3-histidine (50 muCi, 1.8 x 10(-5) M) with and without inhibitors and were processed for LM and EM radioautography. H3-histidine labeled the ECL cells heavily but the A-like and other endocrine cells only lightly. The labeling of ECL cells was only modestly reduced by cycloheximide, an inhibitor of protein synthesis, whereas the labeling of A-like and other endocrine cells was almost abolished. In contrast, the labeling of ECL cells was markedly reduced by 4-bromo-3-hydroxybenzyloxyamine (NSD-1055), an inhibitor of histidine decarboxylase and DOPA decarboxylase, but was not appreciably affected by carbidopa, an inhibitor of only the DOPA decarboxylase. Incubations with H3-histamine (50 muCi, 0.9 x 10(-5) M) failed to label endocrine cells. Thus, this study demonstrates that the ECL but not the A-like cell is the histamine-synthesizing endocrine cell of the rat stomach.
Four cases of small cell carcinoma of the esophagus, histologically indistinguishable from oat cell carcinoma of the lung, were studied by electron microscopy. Three were composed largely of small cells with neurosecretory granules characteristic of APUD (amine precursor uptake and decarboxylation) cells. Two of these three cases also contained foci of squamous or glandular differentiation, or both. The fourth case was classified as reserve cell carcinoma with squamous differentiation, since the tumor cells were devoid of neurosecretory granules but contained desmosomes and bundles of intracytoplasmic tonofilaments. The evidence provided by these four cases and also by the 48 cases previously reported in the literature supports our hypothesis that a totipotent primitive cell serves as the common precursor for squamous cell, adeno-, and small cell carcinoma of the esophagus. The latter can be subdivided into oat cell and reserve cell carcinomas, both having the propensity for further squamous and glandular differentiation. The hypothesis can also be applied to lung cancer.
A case of multiple endocrine adenomatosis (MEA) of mixed type is presented. The syndrome, observed in a 65 year-old female, consisted of multiple neurofibroadenomatosis, medullary thyroid carcinoma, multiple adenomata of the parathyroids, adrenal cortical adenoma and small cell anaplastic bronchogenic carcinoma. Thus, it was composed of type 1 as well as of type 2 MEA. On the basis of another seven cases, collected from the literature, the MEA syndrome of mixed type is reviewed with special reference to the phylogenetic origin of the cells of the APUD system.
Carcinoid tumors are very rare neoplasms, arising from enterochromaffin cells, classified in Apud system, exhibiting an intermediate malignancy, because of their long lasting clinical silence and low evolution to advanced stage. At the same time, these features unfortunately cause a high incidence of lymphatic and liver metastases, visible at first diagnostic approach, which are also determined by aspecific symptoms and signs, especially involving jejunal and ileal carcinoids, as the two cases described, and by very frequent absence, in current clinical practice, of pathognomonic carcinoid syndrome. Two carcinoids located into the distal ileal ansa, strictly adjacent to the ileocecal valve, are reported; the first tumor, accompanied by lymphonodal positivity, the second by a solitary hepatic metastasis, requiring segmentectomy of the liver, in addition to right hemicolectomy.
The Carcinoide tumors are infrequent. The come from neuroendocrine argentafine cells, probably related to cells of the APUD system. They are rarely found in the mediastinum. We are reporting a case, and bringing forward some biological, epidemiological and clinical characteristics. We also emphasize over the diagnosis and treatment, and the basics to evaluate the prognosis.
AgNO3 staining by generally accepted methods revealed the presence of silver-absorptive cells in the liver, particularly in perivascular areas. These cells exhibited positive argyrophilia and argentophilia. Lead haematoxylin staining and Solcia's azo-coupling methods allowed identification of the cells, which can be included among the cells of the APUD system.
PURPOSE: To describe cases of Merkel cell carcinoma. Belonging to the APUD-system tumors, the highly malignant Merkel cell carcinoma affects in 10% the ocular adnexes, 50-60% of the patients develop a metastasis to the lymph nodes, and the five year survival rate is only 38%. 30% of the tumors recur after one year. MATERIAL AND METHODS: In the last eight years the Merkel cell carcinoma was diagnosed in four patients and was treated by wide resection, radiotherapy and cytostatic drugs. Histological and immunohistological examination was performed. RESULTS: In three cases the carcinoma was diagnosed in the upper lid and in one case in the eyebrow. Two patients could not be cured. Characteristic is clinical uniform appearance of the tumor as painless, reddish nodule with smooth surface, telangiectatic blood vessels, fast growing and fast leading to metastasis. Furthermore, the histological characteristics of the tumor were found as well as NSE, S100 proteins and neuroendocrine granula, which allow to classify to the APUD--system and to distinguish from the more benign tumors. CONCLUSIONS: As neuroendocrine tumor the Merkel cell carcinoma represents a high malignant tumor in ophthalmology. The certain diagnosis is only made by histological and immunohistological examination. A full-thickness resection followed by radiation, should be performed as soon as possible.
The Diffuse Endocrine System, to which the so-called APUD (Amine Precursor Uptake and Decarboxylation) cells do belong, gives rise to a group of tumours which may or not secrete amines and/or polypeptide hormones: carcinoids (argentaffinomas, argentaffin or Kultschitzky cell carcinomas). Foregut carcinoids are predominantly of B type (trabecular), argyrophilic, or non-reactive (in about 70% of cases) to silver impregnation. Midgut tumours are generally of A type (insular); more than 80% of them are argentaffinic. Hindgut derived carcinoids are primarily of mixed type; nearly 70% are non-reactive to silver stains. From a cytological standpoint all types may be build up of either small-round, spindle-shaped, polyhedral or cuboidal cells. From a functional point-of-view, the cells are either clear and immature, non-reducing or exhausted. Accordingly, the diagnosis cannot be based alone on silver impregnation or other histochemical methods.
Incorporation of 3H-5 HTP is studied in ultimobranchial cells and thyroid cells of the mouse foetus from the 13th day to the 18th day of gestation. The APUD characteristics of these cells are first observed on the 14th day when the U.B. bodies are included in the thyroid anlage. The silver granules are then localized on the parafollicular cell cords from which C cells of the adult thyroid arize.
In the lung of the red-eared turtle, large numbers of intramural ganglia located in the intraparenchymal connective tissue are demonstrated. Numerous cells in close proximity to the principal ganglionic neurons displayed a bright blue-white formaldehyde-induced fluorescence. Microspectrofluorometric analysis revealed the presence of dopamine (DA) in all cells measured. Subsequent light histochemical staining of the fluorescent sections showed the DA-containing cells to display argentaffinity. Electron microscopy of serial sections revealed cells characterized by dense-cored vesicles corresponding to the intensely formaldehyde-induced fluorescent cells. The argentaffin technique performed directly on ultrathin sections selectively stained the dense-cored vesicles. After fixation with glutaraldehyde followed by dichromate, x-ray microanalysis showed the chromium to be incorporated into the dense granules. Cholinergic-type nerve endings formed axosomatic synaptic contacts with the DA-containing cells, which can therefore be considered as intrinsic postganglionic elements. No efferent synapses from the granule-containing cells to the principal ganglionic neurons could be observed. The granule-containing cells occurred solitarily and in clusters, partially invested with satellite cells, and usually located near fenestrated capillaries; they displayed cytoplasmic processes and indicated emiocytotic granule release. Adjacent granule-containing cells were separated by spaces about 20 nm wide, gradually widening to form intercellular channels with apically projecting microvilli and primary cilia. It is concluded that the intrapulmonary granule-containing cells of the red-eared turtle belong to the APUD system. Furthermore, morphologically these cells appeared to possess a special sensory apparatus which designates them as paraneurons. The possible physiological significance of these intrapulmonary granule-containing cells is discussed.