The cytomorphologic features in fine-needle aspiration (FNA) The thyroid gland is believed to have two distinct primordia: the thyreoglossal duct, which gives rise to the follicular epithelium, and the branchial pouches, which yield cells that differentiate into parafollicular cells (C-cells). Upon neoplastic transformation, the follicular cells generate follicular adenomas and follicular or papillary carcinomas, while Ccells are considered to be the progenitors of medullary carcinomas.Medullary carcinoma of the thyroid (MCT) was first described by Horn, 1 but he failed to separate it from undifferentiated thyroid carcinoma. In 1959, Hazard et al. 2 adapted the term "medullary carcinoma" and recognized the characteristic amyloid stroma. In 1966, Williams 3 and Williams et al. 4 identified the neuroendocrine nature of the tumor by describing its origin in the parafollicular cells and defined the tumor as a neoplasm which is capable of producing calcitonin and which may contain argyrophil tumor cells having intracytoplasmic secretory granules of endocrine type. Besides calcitonin, this tumor may also elaborate other substances, including peptide hormones such as adreno-corticotropic hormone (ACTH) 5 and somatostatin. 6,7 With respect to genetic associations, perhaps 80 -90% of these neoplasms occur sporadically, usually in adults, but 10 -15% are encountered in children and teenagers in welldefined genetic syndromes, all transmitted by autosomal dominant patterns of inheritance. 8 Preoperative recognition of MCT by fine-needle aspiration biopsy (FNAB) enables the surgeon to investigate the patient for a possible multiple endocrine neoplasia syndrome (MEN type II) that might include pheochromocytoma, and to plan the initial surgery with radical neck dissection, if necessary. 2 This study presents the diagnostic results by FNA and the cytomorphological features of 91 histologically verified MCT. Fourteen cases of thyroid tumors were cytologically diagnosed as MCT, but histologic examination yielded discrepant results. These cases are illustrated to discuss the differential diagnosis of MCT and its potential pitfalls. Materials and MethodsWe reviewed the aspirates from 128 patients who were registered in the files of the Department of Cytopathology of the University of Göttingen under the category "medullary carcinoma of the thyroid," between the years 1977-1999. These patients were divided into three groups. The first group was composed of 91 patients with histologically verified MCT. The second group included 14 patients with cytologically diagnosed or suspected MCT but discrepant histologic diagnosis (Table II). For the remaining 23 patients, we had no subsequent histologic examination.A detailed morphological analysis of the 91 histologically verified MCT was done by two cytopathologists. The FNAs were performed with 22-gauge needles, and the air-dried smears were routinely stained by the May-Grünwald-Giemsa (MGG) method.Thirty-seven out of 91 patients with histologically confirmed MCT were males, and 54 were f...
Resonance-enhanced multi-photon ionization time-of-flight mass spectrometry (REMPIITOFMS) has been applied to the detection of volatiles in the headspace of brewed coffee and in the coffee roasting process-gas. A frequency quadrupled Nd : YAG laser (266 nm) was used for REMPI ionization (REMPI@266nm) of the volatiles in an effusive molecular beam inside the ion source of a linear TOF mass spectrometer. A special sampling system provided a time correlated sampling. Under these circumstances REMPI@266nm is highly selective for ionization of phenolic compounds. Several phenolic compounds, such as the flavour-active 4-vinylguaiacol, can be detected in the headspace of coffee brew as well as in the roast off-gas with the application of this approach.Moreover, the nitrogen heterocyclic compounds, indole and caffeine, were detected in both cases.During the roasting process the relative changes in concentration of some volatile components of coffee have been recorded by EMPIm266nm with a time resolution of 1 Hz. The different volatiles exhibit characteristic concentration profiles as a function of the roast time. These results demonstrate the applicability of REMPI-TOFMS for on-line monitoring of coffee processing technologies. Such an on-line monitoring technique is of particular interest for process-control purposes, e.g. quality-protection or feedback process control. For example, monitoring of off-gases from the coffee roast process or monitoring of certain unit operations during the instantcoffee manufacturing could be promising industrial applications.Next to wheat, coffee represents the second most important food in world trade.' Taking the high value of coffee and its world production of 5 . 4~ lo6 tons into account, the large commercial importance of coffee-processing is obvious. This is particularly true for the roast process, as the typical coffee flavour mostly arises during the roasting of the green coffee beans. Standard roast processes last 8-12 min at 180-240 "C. Compared to this, more progressive, faster processes take 2-3 min at 300 OC.' During the roast process, thousands of different chemical compounds are are produced by pyrolysis of the organic material of the green coffee beans. About 800'. volatile compounds have been identified and many of them contribute to the coffee flavour.The analysis of coffee volatiles is still a challenge for modem trace analysis. Usually, extensive and time-consuming enrichment, sample preparation and clean-up procedures (adsorptive trapping, steam distillation, fractionation. liquid chromatographic separations etc.) are necessary prior to an instrumental analysis by methods such as gas chromatography/mass spectrometry (GUMS) or highperformance liquid chromatography (HPLC).' A lot of work has been done, using these highly sophisticated analytical techniques. to identify compounds that are decisive for the unique taste and flavour of coffee and, therefore, probably most of the major flavour-active substance classes are known.Due to the fundamental importance of the roast ...
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