Immunohistochemical features of paragangliomas.

Immunohistochemistry is part of the routine diagnosis of the neuroendocrine tumors. In our study, we included 52 paragangliomas with various localizations by routine histology and immunohistochemistry. In order to increase the diagnostic specificity, a complex immunohistochemistry panel has been performed consisting of Bcl-2, Ki-67, Bax and Pituitary Adenylate Cyclase-Activating Peptide (PACAP), somatostatin, VIP and Calcitonin Gene Related Peptide (CGRP). After heat induced antigen retrieval, the immunostaining was performed by StreptABC using DAB as a chromogen. We were the first to demonstrate the presence of Bax and PACAP in paragangliomas. Some of the used markers are of prognostic value. The relationship between Bcl-2 and Bax is decisive in generating the final response to the input apoptotic signals. The Ki-67 antigen staining has gained wide acceptance in prognostic evaluation of other tumor types. We noted a small number of Ki-67 positive cases, which signifies a low mitotic activity of these tumors and a relatively high number of Bax positivities (32.9%) and the much lower number of Bcl-2 positivities (11.39%), and could explain the benign behaviour of paragangliomas.

Structural characteristics and functional significance of the buccal fat pad (corpus adiposum buccae).

Corpus adiposum buccae (c.a.b.) was studied on 42 human subjects (fetuses and adults) using microdissection under magnifying glass after injection of the great vessels of the head with plastics, transparency technique of Spalteholtz and current histological methods. In fetuses, c.a.b. appeared as a well-developed mass located between Buccinator and inferior border of the Masseter. In adults, it emanated three prolongations among which the anteriorly directed molar prolongation was more conspicuous in edentulous old people. Externally, it was covered by a fine conjunctival wrap, which sent septa dividing the buccal fat pad in a series of minute fibroadipous compartments. C.a.b. contained a rich vascular network deriving from the branches of the facial and maxillary arteries. In this vascular net a more developed artery emanated branches to the prolongations of the c.a.b. The veins were tributaries of the pterygoid venous plexus. Beside the vessels, c.a.b. contained also lymphatics and myelinated nerves. The authors postulated that c.a.b. assumed the following functions: a) It filled up the masseter-zygomaticus-buccinator space forming an amortizing and a slipping platform for the masticatory muscles in action; b) in the baby, it resisted to the negative pressure which acted into the buccal cavity during sucking; c) its rich venous net, provided with valve-like structures, may be implicated in the exo-endocranial blood flow by means of the pterygoid plexus.

The aberrant retroesophageal right subclavian artery.

Two cases with arteria lusoria were found at 278 routine dissections. These arteria arise as the last branches of the aortic arch and have a retroesophageal position. At the crossing point, the esophagus narrows due to the groove caused by the artery. The appearance of this malposition is the consequence of the perturbation in the organo-genesis of the right dorsal aorta and fourth branchial artery. The aberration can lead to disphagia lusoria.

Regeneration of intrahepatic biliary ducts after subtotal hepatectomy in rats.

The regenerative morphogenesis of intrahepatic biliary ducts in subtotally hepatectomized rats was studied at 3, 7, 14 and 21 days after operation. Histological findings showed that during the postmitotic stage of hepatoregeneration, between the 1st and 2nd postoperatory week the regenerated biliary structures appeared in close connection with the newly formed vasculo-connective portal spaces. The poorly differentiated periportal cells generated through a gradual metamorphosis the bordering cells of the regenerating intrahepatic biliary ducts. These plead for the similarity of histogenetic mechanisms in regenerative and embryofetal cholangiogenesis.

[Anatomical variations of the nervus alveolaris inferior and their importance for the practice (author's transl)]. / Die anatomischen Variationen des Nervus alveolaris inferior und ihre Bedeutung in der Praxis.

The authors have studied the anatomic variations of the inferior alveolar nerve (N. alveolaris inferior) in 18 human heads. The mandibular nerve being free by medial abord. At about half of the studied cases the M. pterygoideus medialis presents a widened insertion extending on the posterior border of the Ramus mandibulae. Before entering into the mandibular channel the inferior alveolar nerve separated from the next elements by expansion of "aponévrose interptérygoidienne". At this level gets sympathic branches from the plexus caroticus externus et internus, making a plexiform structure interfering sometimes a vegetative ganglion formation. At 16.6% of the cases between the alveolar inferior nerve and the lingual nerve are established connection bridges more or less developed. They have an asymetric aspect. There were observed evident connections between the inferior alveolar nerve and the auriculotemporal nerve taking a mono- or pluriradicular form. The mylohyoidian nerve on his homonymous way gives 2--3 sensitive, or vegetative branches to the bone. Practically speaking are important the branches coming from the precanalicular portion of n. alveolaris inferior perforating the periost and penetrating independently in to mandibula through separated vents. These results are practically useful in Stomatological technique explaining from an anatomically point of view the inefficiency of mandibular anaesthesia in some cases although it is correctly applied.

Data concerning the histogenesis of intrahepatic biliary ducts in human embryofetal life.

The development and histostructural organization of intrahepatic biliary ducts were studied on a human embryofetal material 6 to 32 weeks old. These formations appeared during the whole study period, in close connexion with the extension of the portal vasculo-connective spaces. In the epitheliomesenchymal contact area, the liver cells of limiting plates possessing an increased histogenetic plasticity will generate, through a metamorphosis process, the bordering epithelia of intrahepatic biliary structures.

Data concerning the interpretation of biliary neocanaliculi in prolonged biliary stasis.

Using the model of cholestasis after ligation of the common bile duct in the rat, some aspects concerning the ductular neoformation were studied. The authors' observations sustain the hepatocytic origin of neoformed tubular structures by a process of regressive metamorphosis of the hepatic cells which is to be considered as a dedifferentiation phenomenon. Neocanaliculi appear in relation with hyperplastic connective tissue through which the liver could regain its embryofetal cholangiogenesis.

Spontaneous reversibility of advanced toxic liver cirrhosis.

The spontaneous restoration of liver cirrhosis induced by 6 and 9 month CC14 treatment has been studied. The OH-proline content of the liver stroma, the DNA content of the parenchyma, and the Co/DNA ratio were determined. Observations lasted for 4 months after completion of treatment. Cirrhosis developed after 6 month, CC14 administration was reversible in 3--4 months after the discontinuation of treatment; the normal stroma parenchyma ration had gradually normalized. Nine month treatment exhausted the capacity of the stroma for spontaneous recovery and the parenchyma regenerated to a lesser extent. Fibrosis remained practically irreversible 4 months after CC14 administration.

Effects of the liver homogenate obtained following partial hepatectomy on cirrhosis of the liver.

The authors studied the influence of liver homogenates as a whole and collected at various intervals after partial hepatectomy on cirrhosis of the liver. The lyophilized homogenates were administered over a period of 6 weeks to various groups of albino rats pretreated with CCl4 for a period of 6 months. The normal liver homogenate did not influence the histological and biochemical picture of the hepatocirrhosis. The material collected 48 hours after partial hepatectomy causes a moderate stimulation of the mechanisms of parenchymatous regeneration. 7 days after partial hepatectomy (in the postmitotic period) the hepatic regenerate shows a biological effect with lysis of collagen fibres and protection of parenchymatous cells.

Data regarding the restorative effects of the partial removal of the liver in advanced stages of toxic cirrhosis.

The effects of subtotal hepatectomy of albino rats liver cirrhois at 6 and 9 months after the start of CCl4 administration were studied. The results were assessed through self-control and comparison with similar groups in which the spontaneous reversibility of cirrhotic lesions was followed. In the group of 6 months, the liver exeresis results in normalization of morphological and biochemical liver aspects within a period of one month from the intervention. In the group of 9 months, one may also note a stimulation of the regenerative capacity of parenchyma and marked collagenolytic effects without the complete restoration of the stroma/parenchyma ratio. It seems that the major exereses are also effective in the advanced stages of liver cirrosis once the threshold of spontaneous reversibility has been exceeded.