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At least 415 records · Page 23Linked to original sources
PubMed1980

Effects of left anterior fascicular block on the depolarization process as depicted by total body surface mapping.

To examine the effects of left anterio fascicular block (LAFB) on the depolarization process as manifested on the body surface, 142 lead maps were recorded in 25 subjects with LAFB. Three abnormalities were detected: (1) In the early and mid portion of QRS, twenty of 25 subjects showed abnormal anterior superior positivity, starting in the precordial area and proceeding toward the left subclavicular area. The explanation was thought to be the relatively delayed, dysynchronous, and superiorly directed altered sequence of depolarization of the anterior left ventricle. (2) All the subjects showed left lower abnormal negativity. This was thought to represent the unopposed receding activation front after the left ventricular breakthrough posteroinferiorly and also the negative aspect of the abnormally directed superior positivity. (3) Eleven subjects showed abnormal negative potentials at the right lower chest. This was thought to represent the partially unopposed activation fronts of the right ventricular free wall seen after right ventricular epicardial breakthrough, because of the absence of the usually cancelling normal forces from the anterior portion of the left ventricle. Additionally, the surface manifestation of the septal depolarization was found to be indistinguishable from nornal. This study further enhances our understanding of the altered sequence of depolarization in LAFB, as manifested on the body surface instant-by-instant.

Bundle-Branch Block↗
PubMed1978

Electron microscopic observations on neuron-like cells in the ground squirrel pineal gland.

Ultrastructural details of neuron-like cells as well as synaptic nerve endings in the pineal gland of the ground squirrel are described. The neuron-like cells are situated mainly in the distal portion of the gland. Since the neuron-like cells differ considerably from the pinealocytes and exhibit cytological features characteristic of nerve cells, they are presumably true neurons. The cell bodies or processes of the neuron-like cells receive many synapses. The nerve endings synapsing on these cells contain numerous small non-granulated and some large granulated vesicles but no small granulated vesicles. These synaptic nerve endings are rather abundant within the parenchyma but they are also found in perivascular spaces ensheathed completely or partially by the Schwann cell cytoplasm. Similar nerve endings occasionally make typical synaptic contacts with the cell bodies or processes of the pinealocytes. Since the adrenergic nerve endings do not form synapses on the pinealocytes in the ground squirrel, it is clear that nerve endings other than adrenergic ones also distribute within the pineal gland of this animal. These synaptic nerve endings may contribute, at least to some extent, to the innervation of the ground squirrel pineal gland, whether they are derived from the nerve fibers penetrating the pineal gland or from the neuron-like cells.

Adrenergic Fibers↗
PubMed1985

Qualitative and quantitative observations of spiral ganglion development in the rat.

The postnatal development of the spiral ganglion cells in the rat was studied from birth until the adult stage. At birth, a single population of ganglion cells is present. Some of them are surrounded by one or two layers of satellite cell processes. With maturation, the satellite cell processes increase in number around the cell body and its processes. At the end of the first postnatal week, two important events occur. The first is the appearance of myelin lamellae between the 4th and the 6th postnatal day in both ganglion cell processes, and between the 6th and the 8th day in the cell body. The second event is the appearance of a new type of cell (the Type II spiral ganglion cell) on the 6th to the 8th day postpartum. At this stage, the Type II cell is mainly characterized by densely packed neurofilamentous structures in the cytoplasm. Comparison between the myelination of the cell body and its processes reveals three main differences! There is a time lag of approximately 2 days between the onset of myelination in the cell body and in its processes. The kinetics of myelination are different in the cell processes and in the cell body. The myelination of the cell body starts slowly, whereas it is very fast in the processes. Later, the kinetics of myelination decrease in the processes, and increase in the cell body. At all stages including the adult, the fibers have a myelin sheath composed of more lamellae than the cell body. These observations are discussed with respect to development in other species.

Aging↗
PubMed1961

Fowler's bacillus and its parasporal body.

Fowler's bacillus is one of several organisms which form a non-viable inclusion or parasporal body during the process of sporulation. This body is globular and may be as large as or larger than the spore. Its position in the cell is not random; the spore is terminal and the body paracentral, lying between the spore and the remaining vegetative cell chromatin bodies. On completion of sporulation both spore and body are contained within an exosporium. The sequence in the development of the cell structures was followed in ultrathin sections of material fixed in permanganate. When sporulation is well advanced the body begins to grow from a single crystal, then presumably as a result of some disorientation in the growth process it develops as a multicrystalline body with the lattices orientated at different angles. When the body approximates the spore in size, a lamella coat is formed and an exosporium develops which eventually encircles the body and the spore. Other lamella systems microscopically similar to those surrounding the parasporal body develop free in the cytoplasm outside the exosporium. In both of these systems the number of lamellae is variable. The spore coat of Fowler's bacillus, consisting of an outer lamella layer and an inner unresolved amorphous layer has been found microscopically identical to the spore coat of B. cereus. In both organisms the lamella layer of the spore coat consists, in contrast to the other lamella systems, of a regular number of lamellae. Physiological tests would indicate that Fowler's bacillus is a variety of B. cereus.

Animals↗
PubMed2006

Oligodendrocytes express P2Y12 metabotropic receptor in adult rat brain.

In the CNS, nucleotide receptors termed P2 receptors are identified on neurons and glial cells, mediating neuron-neuron, glia-glia and glia-neuron communication. In the present work, we qualify in vivo in the adult rat CNS the cellular/subcellular distribution of P2Y12 receptor protein in cerebral cortex, white matter and subcortical nuclei (striatum and substantia nigra), by means of immunofluorescence-confocal, electron microscopy and Western blot analysis. P2Y12 receptor immunoreactivity colocalizes neither with markers such as neuronal nuclei, neurofilament light chain, calbindin and tyrosine hydroxylase, nor with glial fibrillary acidic protein and isolectin B4, but with myelin basic protein and the oligodendrocyte marker RIP, in both cell bodies and processes, indicating therefore oligodendrocyte localization. Electron microscopy identifies P2Y12 receptors in both the perikaryon and under the plasmalemma of oligodendrocyte cell bodies and radiating processes, until the paranodal region of fibers. By Western blot analysis, P2Y12 receptor shows a specific band of 42-44 kDa, matching the molecular mass predicted from amino acid sequencing. Since in platelets P2Y12 receptor is known to regulate adhesion/activation and thrombus growth/stability, from our results we could speculate by analogy that, in oligodendrocytes, P2Y12 receptor signaling might contribute to the migration and adhesion of the glial processes to axons to be myelinated.

Animals↗
PubMed2004

Increased expression of vasopressin v1a receptors after traumatic brain injury.

Experimental evidence obtained in various animal models of brain injury indicates that vasopressin promotes the formation of cerebral edema. However, the molecular and cellular mechanisms underlying this vasopressin action are not fully understood. In the present study, we analyzed the temporal changes in expression of vasopressin V1a receptors after traumatic brain injury (TBI) in rats. In the intact brain, the V1a receptor was expressed in neurons located in all layers of the frontoparietal cortex. The V1a receptor-immunoreactive product was predominantly localized to neuronal nuclei and had both a diffused and punctate staining pattern. The V1a receptors were also expressed in astrocytes, especially in layer 1 of the frontoparietal cortex. In these cells, two distinctive patterns of immunopositive staining for V1a receptors were observed: a diffused cytosolic staining of cell bodies and processes and a clearly punctate staining pattern that was predominantly localized to the astrocytic cell bodies. The real-time reverse-transcriptase polymerase chain reaction analysis of changes in mRNA for the V1a receptor demonstrated that after TBI, there is an early (4 h post-TBI) increase in the number of transcripts in the ipsilateral frontoparietal cortex, when compared to the contralateral hemisphere or the sham-injured rats. This increase in the message was followed by the up-regulation of expression of the V1a receptors at the protein level. This was most evident in cortical astrocytes in the areas surrounding the lesion. The number of the V1a receptor-immunopositive astrocytes in the traumatized parenchyma gradually increased, starting at 8 h and peaking at 4-6 days after TBI. Furthermore, a redistribution of V1a receptors from the astrocytic cell bodies to the astrocytic processes was observed. In addition to astrocytes, an increased expression of V1a receptors was found in the endothelium of both blood microvessels and the large-diameter blood vessels in the frontoparietal cortex ipsilateral to injury. This increase in the V1a receptor expression was apparent between 2 and 4 days after TBI. As early as 1-2 h following the impact, there was also a striking increase in the number of the V1a receptor-immunopositive beaded axonal processes, with greatly enlarged varicosities, that were localized to various areas of the injured parenchyma. It is suggested that the increased expression of V1a receptors plays an important role in the vasopressin-mediated formation of edema in the injured brain.

Animals↗
PubMed2001

Differential mRNA localization in astroglial cells in culture.

Messenger RNA (mRNA) targeting to specific subcellular domains has been studied extensively in many cell types, and there is increasing evidence suggesting that mRNA sorting also occurs in astrocytes. As a step toward developing strategies to evaluate the signals that govern mRNA sorting in astrocytes, the authors studied the subcellular distribution of several representative mRNAs, poly(A) RNA and ribosomal RNA, in process-bearing (type-2) astroglial cells in culture. Nonradioactive in situ hybridization analysis revealed a gradual increase in the expression of glial fibrillary acidic protein (GFAP) mRNA as type-2 astrocytes differentiated in culture. In mature cells, labeling was present in both cell bodies and processes. GFAP mRNA labeling was granular in nature and was particularly concentrated at branch points and at the tips of the processes. Unlike GFAP mRNA, vimentin, beta-tubulin, and beta- and gamma-actin mRNAs were mainly confined to the cell bodies, with only occasional labeling seen in the processes. Nonradioactive and radioactive in situ hybridization analysis of poly(A) and ribosomal RNA, respectively, revealed labeling in cell bodies and processes of immature and differentiated astrocytes. Treatment with nocodazole, a microtubule depolymerizing agent, resulted in a substantial reduction of GFAP mRNA labeling in the processes, whereas treatment with cytochalasin D, a microfilament-disrupting agent, did not alter GFAP mRNA distribution. The results indicate that cultured type-2 astrocytes have the capacity to sort mRNAs to different subcellular domains and that the localization of GFAP mRNA to astrocyte processes requires intact microtubules.

Actins↗
PubMed1994

Selective processing of food and body size words: application of the Stroop Test with obese restrained eaters, anorexics, and normals.

The specificity of the retardation effect on the Stroop Naming task with eating disorder clients was examined by comparing anorexic patients and normal weight controls with obese restrained eaters. Although the expected differences between normal weight controls and anorexics were found for color naming of food and body size words, obese restrained eaters were not differentiated from the clinical sample. It is suggested, therefore, that the Stroop phenomena do not have a precise relationship to the extent of psychopathology and that factors such as the ability to "fake" the test and poor concentration leading to general slowing, may explain the results.

Adolescent↗
PubMed1989

Immunohistochemical demonstration of neurotensin and tyrosine hydroxylase in iris nerves of the rabbit eye.

In previous studies we have provided evidence that intracameral administration of neurotensin (NT), an endogenous tridecapeptide, produces strong miosis in the rabbit. The presence of NT immunoreactivity was investigated in rabbit iris whole mounts by light microscopic immunohistochemistry, and its distribution in the iris compared to that, of tyrosine hydroxylase (TH). A few scattered NT-positive cell bodies were localized in the dilator muscle. Both, the NT cell bodies and processes appeared parallel to the muscle cells. Extensive branching of NT-containing cell processes was observed in connection with the sphincter muscle. These NT-positive fibers formed a dense, randomly oriented network throughout the sphincter muscle cells. The distribution of TH immunoreactivity was similar to that of NT-positive cell processes, except that no TH-positive cell bodies were detected in any of the iris structures examined. Moderate branching of TH-positive fibers was observed in the dilator and sphincter iris muscles. These findings provide neuroanatomical support for an important role of NT in pupillary physiology. Its similar topographical distribution with TH suggests that NT and dopamine may be co-localized, as it has already been described in brain.

Animals↗
PubMed2006

Determinants of Rbp1p localization in specific cytoplasmic mRNA-processing foci, P-bodies.

Rbp1p, a yeast RNA-binding protein, decreases the level of mitochondrial porin mRNA by enhancing its degradation, but the intracellular location of the Rbp1p-mediated degradation complex remains unknown. We show here that Rbp1p in xrn1Delta mutant yeast localizes in specific cytoplasmic foci that are known as P-bodies. The N-terminal and RNA recognition motif (RRM) 1 domains of Rbp1p are necessary but not sufficient for its localization in P bodies. Rbp1p forms oligomers through its C-terminal domain in vivo; N-terminal-delete, or RRM1-mutated Rbp1p can be more efficiently recruited to P-bodies in an xrn1Delta strain, expressing a full-length Rbp1p. Although POR1 mRNA is localized to P bodies in an xrn1Delta strain, this localization does not depend on Rbp1p. Decapping activator Dhh1p directly interacts with Rbp1p. However, the recruitment of Rbp1p to P-bodies does not require Dhh1p or Ccr4p. In wild-type cells, Rbp1p can localize to P-bodies under glucose deprivation or treatment with KCl. In addition, Rbp1p-mediated porin mRNA decay is elicited by Xrn1p, a 5 ' to 3 ' exonuclease. These results provide new insight into the mechanism of Rbp1p function.

Cytoplasm↗
PubMed1994

The body's response to processing emotional trauma: linking verbal text with autonomic activity.

When individuals talk or think about upsetting experiences, different coping and defensive processes are invoked from one minute to the next. Further, some coping strategies are thought to be more effortful and to be associated with greater biological activity than others. The present research sought to identify how the expression of emotions and the use of different psychological defenses were reflected in momentary changes in autonomic nervous system activity while subjects wrote about emotional topics. A new methodology is introduced that links the production of natural written language with autonomic activity on a word-by-word or phrase-by-phrase basis. Using this technique with a sample of 24 subjects who wrote about traumatic experiences, it was found that certain text dimensions are highly related to skin conductance level (SCL) but not heart rate. In general, subjects' SCLs increased when expressing negative emotions and when using denial and the passive voice. SCLs were more likely to drop when subjects used positive emotion words and self-references and at the conclusion of sentences or thought units. Implications for this methodology for understanding psychological defense and physical health are discussed.

Adaptation, Psychological↗