Interplay of model ingredients affecting aggregate shape plasticity in diffusion-limited aggregation.

We analyze the combined effect of three ingredients of an aggregation model--surface tension, particle flow and particle source--representing typical characteristics of many aggregation growth processes in nature. Through extensive numerical experiments and for different underlying lattice structures we demonstrate that the location of incoming particles and their preferential direction of flow can significantly affect the resulting general shape of the aggregate, while the surface tension controls the surface roughness. Combining all three ingredients increases the aggregate shape plasticity, yielding a wider spectrum of shapes as compared to earlier works that analyzed these ingredients separately. Our results indicate that the considered combination of effects is fundamental for modeling the polymorphic growth of a wide variety of structures in confined geometries and/or in the presence of external fields, such as rocks, crystals, corals, and biominerals.

Successful treatment of extranodal Hodgkin's lymphoma in a patient with longstanding hairy cell leukemia.

Purine analogs, particularly pentostatin and cladribine, are highly effective in hairy cell leukemia (HCL). Both of these drugs induce responses in approximately 80-95% of patients. However, it is not yet determined if treatment with these drugs can induce second malignancies. Hodgkin's lymphoma is very rare as a second malignancy and there are only 3 reported cases concerning the association of this lymphoma with HCL. We describe a patient with longstanding HCL in complete remission after cladribine, in whom extranodal Hodgkin's lymphoma appeared 8 years after the diagnosis of HCL. Magnetic resonance imaging revealed diffuse intra-osseal neoplastic infiltration of the corpora of the whole spinal column and extra-osseal propagation from the fifth thoracic vertebra into the spinal canal with spinal cord compression. Histological and immunohistochemical analysis of the extradural tumor, which was completely excised, disclosed nodular sclerosis Hodgkin's lymphoma with typical Reed-Sternberg cells that were positive for CD30, CD15, bcl-6, Ki67, p53, EBV LPM-1 and IgG, and negative for CD45, CD20, DBA44, kappa, lambda light chains and IgM. In addition, immunohistochemical analysis of the bone marrow in 1999 showed infiltration with positivity for IgM and negative for kappa light chains and IgG. These findings (expression of different immunoglobulins and light chains on the cells) suggest an independent origin of these 2 B-cell neoplasms. After neurosurgery the patient received 6 courses of the MP-ABVD protocol and achieved a complete remission, which has lasted 16 months thus far.

[The internal thoracic blood vessels (internal thoracic arteries and veins) and their practical significance]. / Unutrasnji grudni krvni sudovi (a. et vv. thoracicae internae) i njihov prakticni znacaj.

Internal thoracic blood vessels (A. et Vv. thoracicae internae) are parietal vessels of the thoracic anterior wall. Because of their position, they are often exposed to injuries during the fracture of the ribs and the sternal bone. These facts require a general knowledge about the anatomical variations of these vessels, specifically the knowledge concerning their mutual relationship, their anastomoses and their distance from the lateral margins of the sternal bone. Due to the poor and different data in the available literature, we directed our investigations towards the study and confirmation of the described anatomical variations of the internal thoracic blood vessels. In this study we investigated the distance between the internal thoracic artery and the lateral margins of the sternal bone, the level of its bifurcation, the number of the internal thoracic veins and anastomoses between them. The investigation was carried out on 300 formalin specimens consisting of the anterior wall of the thorax (persons of different ages and sexes) by using the method of dissection and the method of contrast injection. In adults (200 specimens), the distance between the arterial trunk and the lateral margin of the sternal bone was not equal in the first fifth or sixth intercostal spaces, but in children up to five years of age (100 specimens), the distance was almost the same. In adults, the internal thoracic artery was nearest to the sternal bone in the first intercostal space, but going downward the artery was gradually more and more distant from the sternum and in the sixth intercostal space the distance measured approximately from 11 mm to 13 mm. In children, the distance of the artery from the lateral margin of the sternal bone, just in the above mentioned intercostal spaces, was from 5 mm to 10 mm. There was no difference according to sex in any of the two groups. Most frequently, the internal thoracic artery gave off its terminal branches at the level of the sixth costal cartilage (adults--35% and children--45%), and most rarely, the bifurcation of the artery was at the level of the seventh costal cartilage (adults--10% and children--8%). The internal thoracic vein that accompanies the same named artery, could be either single or double, on one or both sides. In cases of double veins-the artery was situated between the two of them, but in cases of single vein-the vein was located medially to the artery. In 82% of cases in the adult group, and in 69% of cases in the children-group, there were two veins accompanying the artery. The right and the left internal thoracic veins were connected in the region of the sternal bone by the retrosternal venous net (specifically in the region of the manubrium) and by one venous vessel lying in front of the xiphoid process. According to the position and the course of that venous vessel it could be called "arcus venosus prexiphoideus". The internal thoracic blood vessels were enclosed by the unique fascial sheath. They were superiorly separated from the costal pleura by the endothoracic fascia and inferiorly by the transversal thoracic muscle (m. transversus thoracis). The safest approach to the internal thoracic artery was at the level of the second and the third intercostal space. During the approach through some of the lower intercostal spaces it was necessary to be very careful because they could be narrowed at their anterior ends.

Dysmegakaryocytopoiesis and thrombocytosis in a patient with acute myelomonocytic leukemia and long evolution.

A patient with acute myelomonocytic leukemia (M4), dysmegakaryocytopoiesis and thrombocytosis is presented. Immunophenotyping and blast colony assay showed the presence of blasts with IaDr, CD 33 and CD 14 antigens. Cytogenetic analysis and level of thrombopoietin were normal. This atypical case represents yet another example of the transitional zone between atypical myeloproliferative disease and acute leukemia, and the apparent absence of any cytogenetic abnormality is noteworthy.

[Ultrasound as a diagnostic aid in maxillofacial surgery]. / Ultraschall als ein diagnostisches Hilfsmittel in der Kiefer-Gesichts-Chirurgie.

Ultrasonography is a relatively new diagnostic aid in maxillofacial surgery. It can be used in maxillofacial surgery in three modifications: Doppler sonography, A-scan sonography, B-scan sonography. As clinicians we wanted to determine what contribution ultrasound examination has made to the diagnosis of superficial maxillofacial masses, when compared with clinical examination, intraoperative findings and with other methods of investigations. Since 1985 B-scan sonography has been performed in the examination of congenital, inflammatory and neoplastic masses of the head and neck on more than 1500 patients. The ultrasound examination was performed in the Department of Radiology by radiologists. The value of the ultrasound findings varied depending on the soft tissue lesions which were examined and the experience of the radiologists who performed the examination. The advantages of the diagnostic ultrasound are in being noninvasive, without any known deleterious biological effect, rapid, painless, inexpensive and easily reproducible. Ultrasonography is a procedure which nowadays is routinely performed in our department for the preoperative evaluation of our cancer patients and postoperative follow-up as well as for the patients with inflammations, diseases of the salivary glands and soft tissue swellings.