scholarly journals Supranumerary Barrels Develop in the Somatosensory Cortex of Mice, After the Implantation of the Vibrissal Follicle Parts Containing Large Numbers of Receptors

1989 ◽  
Vol 1 (2) ◽  
pp. 33-47 ◽  
Author(s):  
F. L. Andrés

In the mouse whiskerpad there is a group of vibrissal follicles arranged in five rows, which are topologically represented in the contralateral somatosensory cortex by the barrelfield.Each vibrissal follicle is a specialized sensory organ containing a large number of receptors, mostly Merkel cells.In these experiments, the parts of the vibrissal follicles containing most of the receptors were transplanted to different regions of the whiskerpad of newborn mice, to know whether “new”, supranumerary barrels could develop.The results confirm this hypothesis. However, the “new” barrels are not topologically represented in the barrelfield, as normal barrels do.

1971 ◽  
Vol 134 (2) ◽  
pp. 366-380 ◽  
Author(s):  
Richard Costello ◽  
Takateru Izumi ◽  
Takehiko Sakurami

The consequences of Calmette-Guérin bacillus (BCG) vaccination were followed in newborn and adult mice. BCG failed to multiply in the organs of adult mice when administered peritoneally. In contrast, extensive multiplication of the vaccine occurred in both splenic and pulmonary tissue after its peritoneal administration to newborn mice. This absence of tuberculostasis occurred during the period when the animal's spleen, lung, and thymus were rapidly growing. Animals achieved similar levels of resistance to virulent respiratory challenge 10 wk after vaccination irrespective of whether the vaccine had been administered when the mice were newly born and BCG had multiplied in vivo or administered when the animals were fully grown and the BCG had remained in the dormant state. Although neonatal infection with BCG was severe, as shown by the large numbers of organisms recovered from the animals' tissues, the animals suffered no mortality or overt signs of disease. Neonatal vaccination did not significantly affect either the animal's growth rate or the gross development of its organs.


Author(s):  
U.I. Heine ◽  
G.R.F. Krueger ◽  
E. Munoz ◽  
A. Karpinski

Infection of newborn mice with Moloney leukemia virus (M-MuLV) causes a T-cell differentiation block in the thymic cortex accompanied by proliferation and accumulation of prethymic lymphoblasts in the thymus and subsequent spreading of these cells to generate systemic lymphoma. Current evidence shows that thymic reticular epithelial cells (REC) provide a microenvironment necessary for the maturation of prethymic lymphoblasts to mature T-lymphocytes by secretion of various thymic factors. A change in that environment due to infection of REC by virus could be decisive for the failure of lymphoblasts to mature and thus contribute to lymphoma development.We have studied the morphology and distribution of the major thymic cell populations at different stages of tumorigenesis in Balb/c mice infected when newborn with 0.2ml M-MuLV suspension, 6.8 log FFU/ml. Thymic tissue taken at 1-2 weekly intervals up to tumor development was processed for light and electron microscopy, using glutaraldehyde-OsO4fixation and Epon-Araldite embedding.


Author(s):  
T. G. Merrill ◽  
B. J. Payne ◽  
A. J. Tousimis

Rats given SK&F 14336-D (9-[3-Dimethylamino propyl]-2-chloroacridane), a tranquilizing drug, developed an increased number of vacuolated lymphocytes as observed by light microscopy. Vacuoles in peripheral blood of rats and humans apparently are rare and are not usually reported in differential counts. Transforming agents such as phytohemagglutinin and pokeweed mitogen induce similar vacuoles in in vitro cultures of lymphocytes. These vacuoles have also been reported in some of the lipid-storage diseases of humans such as amaurotic familial idiocy, familial neurovisceral lipidosis, lipomucopolysaccharidosis and sphingomyelinosis. Electron microscopic studies of Tay-Sachs' disease and of chloroquine treated swine have demonstrated large numbers of “membranous cytoplasmic granules” in the cytoplasm of neurons, in addition to lymphocytes. The present study was undertaken with the purpose of characterizing the membranous inclusions and developing an experimental animal model which may be used for the study of lipid storage diseases.


Author(s):  
Robert Corbett ◽  
Delbert E. Philpott ◽  
Sam Black

Observation of subtle or early signs of change in spaceflight induced alterations on living systems require precise methods of sampling. In-flight analysis would be preferable but constraints of time, equipment, personnel and cost dictate the necessity for prolonged storage before retrieval. Because of this, various tissues have been stored in fixatives and combinations of fixatives and observed at various time intervals. High pressure and the effect of buffer alone have also been tried.Of the various tissues embedded, muscle, cartilage and liver, liver has been the most extensively studied because it contains large numbers of organelles common to all tissues (Fig. 1).


Author(s):  
Roy Skidmore

The long-necked secretory cells in Onchidoris muricata are distributed in the anterior sole of the foot. These cells are interspersed among ciliated columnar and conical cells as well as short-necked secretory gland cells. The long-necked cells contribute a significant amount of mucoid materials to the slime on which the nudibranch travels. The body of these cells is found in the subepidermal tissues. A long process extends across the basal lamina and in between cells of the epidermis to the surface of the foot. The secretory granules travel along the process and their contents are expelled by exocytosis at the foot surface.The contents of the cell body include the nucleus, some endoplasmic reticulum, and an extensive Golgi body with large numbers of secretory vesicles (Fig. 1). The secretory vesicles are membrane bound and contain a fibrillar matrix. At high magnification the similarity of the contents in the Golgi saccules and the secretory vesicles becomes apparent (Fig. 2).


Author(s):  
C. C. Clawson ◽  
L. W. Anderson ◽  
R. A. Good

Investigations which require electron microscope examination of a few specific areas of non-homogeneous tissues make random sampling of small blocks an inefficient and unrewarding procedure. Therefore, several investigators have devised methods which allow obtaining sample blocks for electron microscopy from region of tissue previously identified by light microscopy of present here techniques which make possible: 1) sampling tissue for electron microscopy from selected areas previously identified by light microscopy of relatively large pieces of tissue; 2) dehydration and embedding large numbers of individually identified blocks while keeping each one separate; 3) a new method of maintaining specific orientation of blocks during embedding; 4) special light microscopic staining or fluorescent procedures and electron microscopy on immediately adjacent small areas of tissue.


Author(s):  
J.M. Titchmarsh

The advances in recent years in the microanalytical capabilities of conventional TEM's fitted with probe forming lenses allow much more detailed investigations to be made of the microstructures of complex alloys, such as ferritic steels, than have been possible previously. In particular, the identification of individual precipitate particles with dimensions of a few tens of nanometers in alloys containing high densities of several chemically and crystallographically different precipitate types is feasible. The aim of the investigation described in this paper was to establish a method which allowed individual particle identification to be made in a few seconds so that large numbers of particles could be examined in a few hours.A Philips EM400 microscope, fitted with the scanning transmission (STEM) objective lens pole-pieces and an EDAX energy dispersive X-ray analyser, was used at 120 kV with a thermal W hairpin filament. The precipitates examined were extracted using a standard C replica technique from specimens of a 2¼Cr-lMo ferritic steel in a quenched and tempered condition.


Author(s):  
C. Uphoff ◽  
C. Nyquist-Battie

Fetal Alcohol Syndrone (FAS) is a syndrome with characteristic abnormalities resulting from prenatal exposure to ethanol. In many children with FAS syndrome gross pathological changes in the heart are seen with septal defects the most prevalent abnormality recorded. Few studies in animal models have been performed on the effects of ethanol on heart development. In our laboratory, it has been observed that prenatal ethanol exposure of Swiss albino mice results in abnormal cardiac muscle ultrastructure when mice were examined at birth and compared to pairfed and normal controls. Fig. 1 is an example of the changes that are seen in the ethanol-exposed animals. These changes include enlarged mitochondria with loss of inner mitochondrial membrane integrity and loss of myofibrils. Morphometric analysis substantiated the presence of these alterations from normal cardiac ultrastructure. The present work was undertaken to determine if the pathological changes seen in the newborn mice prenatally exposed to ethanol could be reversed with age and abstinence.


Author(s):  
H. J. Arnott ◽  
M. A. Webb ◽  
L. E. Lopez

Many papers have been published on the structure of calcium oxalate crystals in plants, however, few deal with the early development of crystals. Large numbers of idioblastic calcium oxalate crystal cells are found in the leaves of Vitis mustangensis, V. labrusca and V. vulpina. A crystal idioblast, or raphide cell, will produce 150-300 needle-like calcium oxalate crystals within a central vacuole. Each raphide crystal is autonomous, having been produced in a separate membrane-defined crystal chamber; the idioblast''s crystal complement is collectively embedded in a water soluble glycoprotein matrix which fills the vacuole. The crystals are twins, each having a pointed and a bidentate end (Fig 1); when mature they are about 0.5-1.2 μn in diameter and 30-70 μm in length. Crystal bundles, i.e., crystals and their matrix, can be isolated from leaves using 100% ETOH. If the bundles are treated with H2O the matrix surrounding the crystals rapidly disperses.


Author(s):  
Thomas T.F. Huang ◽  
Patricia G. Calarco

The stage specific appearance of a retravirus, termed the Intracisternal A particle (IAP) is a normal feature of early preimplantation development. To date, all feral and laboratory strains of Mus musculus and even Asian species such as Mus cervicolor and Mus pahari express the particles during the 2-8 cell stages. IAP form by budding into the endoplasmic reticulum and appear singly or as groups of donut-shaped particles within the cisternae (fig. 1). IAP are also produced in large numbers in several neoplastic cells such as certain plasmacytomas and rhabdomyosarcomas. The role of IAP, either in normal development or in neoplastic behavior, is unknown.


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