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The aim of this work is to describe the structure of the thymus, especially its medullary part, in children with congenital heart defects. It is known that development of the thymus and the heart is also influenced by neural crest cells. During the early development of the heart and the thymus cells proliferate and migrate to their primordia. It is known that inadequate cephalic neural crest contribution during development of pharyngeal pouch derivatives results in defective organogenesis of the face, the thymus, parathyroid glands and also the heart. We studied the structure of the thymus in children with congenital heart defects from 0 to 12 years of life at light microscopic and electron-microscopic levels. Thymuses of the patients were surgically removed in the Children’s Cardiocenter in Bratislava. The results of our study confirmed the differences in the medullary structures of thymuses with chosen diagnoses. Hassall’s corpuscles in the thymic medulla were various in size and also in structure and number. The special structures of the thymic medullary region in children with ventricular septal defects and defects of outflow of the heart were big cystic Hassall’s corpuscles. In comparison with a size of Hassall’s corpuscles in normal thymuses the size of Hassall’s corpuscles in studied thymuses suprisingly ranged between 100–250 μm.

Paleal notochaetae belonging to a number of Chrysopetalum species (Chrysopetalidae) were examined by scanning and transmission electron microscopy. Paleae are composed of broad medullary channels stacked with a regular series of horizontal fibrous diaphragms. The medullary part of the palea is surrounded by irregular rows of narrow tubular channels within the chaetal cortex. The origin and function of camerate chaetae is discussed.

Erwinia chrysanthemi (biovars 5 and 6) was isolated from unusual symptoms on witloof chicory, both in the field and in hydroponic culture, in Brittany in 1989 and 1990. Symptoms included a greyish-brown soft rot on the lower part of the root and the destruction of the cortical tissues. The cribrovascular and the medullary part of the bottom of the root sometimes became slimy. A few cases of vascular transmission were observed, which resulted in a red coloration of the infected vessels and a soft rot of the leaves (...)

A significant activity of L-[3H]glutamic acid binding was detected in the membranous particulate preparations obtained from the rat adrenal glands. In vitro addition of sodium acetate (100 mM) resulted in a drastic enhancement of the binding to cerebral preparations, while inducing a significant inhibition of the adrenal binding. Quisqualic acid elicited a prominent suppression of the adrenal binding in a concentration-dependent manner to a slightly greater extent than the inhibition of cerebral binding. N-Methyl-D-aspartic acid exerted a significant stimulatory action on the adrenal binding without affecting the cerebral binding. The adrenal medullary part possessed more than 5-fold higher binding activity than that in cortical part. These results suggest the possible existence of [3H]glutamate binding sites in rat adrenal glands which are distinctly different from those in the central structures.

A clinical and pathologic analysis of 30 lipid cell tumors of the ovary shows that both adrenocortical-like and hilus-like cells are present in most instances and that attempts to separate them objectively into adrenal-like tumors, hilus cell tumors or stromal luteomas is often impossible. Inasmuch as there is no histogenetic basis for employing this terminology, such a separation is considered artificial and of no value in predicting either functional manifestations or clinical behavior. Therefore, lipid cell tumors are regarded as a specific entity and not a collection of different lesions. Lipid cell tumors are most often virilizing (77% of patients) and may be associated with Cushing's syndrome (10% of patients) or with evidence of estrogenic activity (23% of patients). Although these tumors usually are considered benign, six patients in this series died of recurrent or metastatic tumor. The clinically malignant lipid cell tumors tended to be larger than the benign ones, had involved contiguous pelvic structures at the time of operation in half of the cases, and occasionally exhibited sufficient cellular pleomorphism and mitotic activity to permit objective interpretation as malignant. On the basis of the authors' findings and the evidence available in the literature, the most likely origin of lipid cell tumors is from the specialized ovarian stromal cells within the medullary part of the ovaries.

1. An experimental study of the healing mechanism in circumscribed defects in femora of albino rats of the Wistar strain is described. 2. Only the outer one-fifth of the defect is repaired by subperiosteal bony callus, the rest of the defect being repaired by endosteal callus. 3. Subperiosteal callus does not bridge the defect until endosteal callus is developed fully. 4. As peripheral callus matures the greater part of the endosteal callus is resorbed, with the exception of trabeculae attached to the margin of the defect. 5. The resorbed area in the medullary part of the defect is gradually obliterated by deposition of inner circumferential lamellae. 6. There appear to be differences between the mechanism responsible for repair of fractures of a long bone and that which heals circumscribed bone defects.