Computed tomography in the diagnosis of periodontal changes

The paper shows how volumetric reconstruction of jaw images can be used and analyzes the plots of planar characteristics of cortical plates in different forms of periodontitis. Clinical and X-ray parallels in this disease are discussed.     

Effect of thermoreverse polymer matrix and collagen on the growth of human fibroblasts]

The effect of a support composed of polymers based on poly-N-isopropyl acrylamide and poly-t-butyl acrylamide and collagen on human fibroblasts was studied. As the temperature was decreased to 4 degrees C, the polymeric support is converted to a diluted state and cells spontaneously detached from it. The presence of collagen in the support prevented the detachment of cells and increased cell growth. It was shown by microcalorimetry, that in a copolymer-collagen mixture, a microstratification takes place.     

The distribution of PBAN (pheromone biosynthesis activating neuropeptide)-like immunoreactivity in the nervous system of the gypsy moth,Lymantria dispar

The production of sex pheromone in many moths is regulated by the neuropeptide PBAN (pheromone biosynthesis-activating neuropeptide). Studies in a number of species have shown that pheromone production can be linked to a hemolymph factor and that continuity in the ventral chain of ganglia is not required. However, it has recently been shown that production of pheromone in the gypsy moth, Lymantria dispar, is largely prevented in females with a transected ventral nerve cord (VNC). To begin to understand the cellular basis for this dependence on the VNC, we sought to determine the distribution of PBAN in the central nervous system and its neurohemal sites, including those associated with the VNC. Using an antiserum to L. dispar-PBAN in immunocytochemical methods, we have mapped the distribution of PBAN-like immunoreactivity (PLI). PLI is found in three clusters of ventral midline somata in the subesophageal ganglion (SEG), in three clusters of midline cells in each segmental ganglion, and in bilateral pairs of cells located posterolaterally in each abdominal ganglion. The SEG cells comprise both interneurons, with endings in the neuropil of each segmental ganglion, as well as neurosecretory cells, with endings in the retrocerebral complex and in an unusual neurohemal structure near the anterior aspect of the SEG. The latter structure, which we have named the corpus ventralis, receives axons from the two anterior clusters of cells in the SEG. In the abdominal ganglia, the posterolateral clusters of cells have immunoretroreactive axons exiting the ganglia via the ventral nerves. Endings of these axons reach the perivisceral organ in the next posterior ganglion and pass anteriorly into the median nerve, forming additional varicose endings. We did not detect PLI in the terminal nerve. Thus, our findings raise the possibility that the requirement for an intact VNC in pheromone production reflects a role for descending regulation of neurosecretory cells in the segmental ganglia. Arch. Insect Biochem. Physiol. 34:391–408, 1997. Published 1997 Wiley-Liss, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

     

Effect of amphotericin B and its combination with 5-fluorouracil on the development of transplantable rat lymphosarcoma]

The studies were carried out on rats with subcutaneously transplanted metastizing Pliss lymphosarcoma. The animals were treated with amphotericin B administered intravenously in complex with sodium desoxycholate in doses of 336 and 20 Units/kg for 7 days beginning from 24th hour after the tumor transplantation. The treatment resulted in a statistically reliable inhibition of the tumor metastasizing as compared to the control animals. When the animals with the tumors were subjected to combined therapy with 5-fluoruracyl and amphotericin B, the antitumor and antimetastatic effect of 5-fluoruracyl significantly increased. Determination of amphotericin B binding with the organ homogenates showed that the antibiotic bound with the homogenates or the organs of the rats with the tumors to a greater extent than with those of the intact animals. The levels of the antibiotics in the tumor metastases were higher than those in the primary tumors.     

Some topical problems in the use of spiral computed tomography in the treatment of patients with posttraumatic deformities of the middle and upper third of the facial skull

The paper presents a procedure for examining patients with posttraumatic deformities of the middle and upper third of the facial skull on a spiral computed tomograph and the schemes for estimating the size of enophthalmos, which permit elimination of eyeball recession.     

Increasing selectivity of defense behavior during development of pied flycatcher nestlings

The development of defense reaction was studied in the wildlife and experimentally in 7 broods of altricial pied flycatcher (Ficedula hypoleuca) nestlings. Field studies demonstrated that passive-defense response first appeared on the 4th day of the nest life. It developed from the cessation of begging in young relatively satiated nestlings to characteristic freezing response independent of the level of feeding motivation in older nestlings. Older nestlings also acquire the defense reaction in response to novel visual stimuli. The efficiency of the natural stimulus for defense behavior (species-specific alarm call) nongradually changes during the nest life attaining the 100% level only on the 11th posthatching day. During the initial phase of defense behavior development, the reaction can be induced by different rhythmically organized stimuli. Later it becomes considerably more selective and other rhythmic and acoustic signals become much less effective than the alarm call.     

Stages of development of retinal photoreceptor cells in postnatal ontogenesis of the pied flycatcherFicedula hypoleuca

Electron microscopic study of the retina of the altricial pied flycatcherFicedula hypoleuca nestlings has permitted identification, in the course of development of photoreceptor cells, of several consecutive stages, each characterized by the appearance in the cell of some new stagespecific structures. At the 1st stage (the presumptive photoreceptor stage), the cell is composed of the nucleus surrounded by a small amount of the cytoplasm and two processes. The 2nd stage is characterized by formation of the inner segment in the apical cell region, while in the distal region, of the cleft (electric) contacts between the photoreceptor axon terminal and the processes of the second neurons. At the 3rd stage, a pile of membrane disks of the outer segment is formed, while in the synaptic region, the first band synapses considered as the chemical ones. At the 4th stage, a lipid droplet appears in a part of the cells, and at the 5th stage, a paraboloid. The photoreceptors of the 6th stage are young cells that continue growing but are already capable for specific functioning. Closely connected with development of the photoreceptor cells is maturation of the Müller’s glia and pigment epithelium, so that every identified stage of the photoreceptor cell development corresponds to a certain structural state of these elements. The possibility of involvement of the forming retinal cells in performance of early behavioral forms is discussed.