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F P White

Publications and source records attributed to F P White.

At least 19 recordsLinked to original sources
PubMed1987

Effects of polyhydroxyl alcohols on protein synthesis in brain slices.

Stressors such as tissue slicing, toxic chemicals, and heat shock applied to cultured cells, organ tissues, or whole animals in vivo induce the synthesis of a 71,000-kilodalton stress protein (SP71) that is not normally present in most organ tissues. In the present experiment, an attempt was made to inhibit selectively the synthesis of SP71 in rat brain tissue slices. Of several manipulations to the brain slice incubation medium that were examined, only addition of very high concentrations of certain polyhydroxyl alcohols, i.e., 1.0 M glycerol, selectively inhibited SP71 synthesis. Glycerol also selectively inhibited SP71 synthesis in heat-shocked cerebral microvascular cells in culture but failed to inhibit SP71 synthesis in anesthetized rats in vivo in response to heat shock. The effects of glycerol on SP71 synthesis are discussed in relationship to current hypotheses concerning the function of SP71.

Alcohols↗
PubMed1986

A monoclonal antibody to the endothelium of rat brain microvessels.

A rat brain fraction enriched with microvessels was used as the immunogen to produce mouse hybridoma cell lines secreting monoclonal antibodies. One of these antibodies, selected from 156 supernatants by enzyme-linked immunosorbent and immunofluorescent assays, reacted only with the endothelium of microvessels in the brain. The endothelium-specific antibody labelled the cytoplasm of microvascular endothelial cells, their luminal membranes, and an extracellular layer, the endocapillary coat, which covered the luminal surface of these cells. In the kidney, the antibody specifically stained the brush border of the proximal tubuli, and in the liver, the antibody specifically stained bile canaliculi. This demonstrates that 3 morphological structures with important transport functions, cerebral microvascular endothelium, brush border of kidney proximal tubuli, and liver bile canaliculi, express the same epitope.

Animals↗
PubMed1986

Isoproterenol induced myocardial necrosis is associated with stress protein synthesis in rat heart and thoracic aorta.

Large doses of isoproterenol, which produced macroscopically visible myocardial necrosis, induced the synthesis and accumulation of a 71,000 dalton protein (SP71) in the heart, aorta, and salivary gland of adult male rats. This protein was identical to a protein that has previously been found to be synthesised in the heart in response to heat shock and tissue slicing. Detectable amounts of SP71 were no longer seen five days after the isoproterenol injection, suggesting that this protein accumulates as part of a cellular response to stress and then degrades during tissue repair.

Animals↗
PubMed1986

College measles.

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Adolescent↗
PubMed1985

Extra-neural glial fibrillary acidic protein (GFAP) immunoreactivity in perisinusoidal stellate cells of rat liver.

The dendritic processes and perinuclear cytoplasm of stellate-shaped perisinusoidal cells in frozen sections of rat liver were specifically labeled with antisera raised independently to glial fibrillary acidic protein (GFAP), the major component of intermediate filaments in astrocytes. A liver protein co-migrating with authentic GFAP and immunoreactive with GFAP antisera was demonstrated with immunoblots of brain and liver extracts enriched in intermediate filament proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). This study presents yet another example of immunoreactivity to GFAP, or a highly similar protein localized outside the CNS, in cells of mesenchymal origin exhibiting some morphological features common to astroglia.

Animals↗
PubMed1983

Postnatal development of a cellular response to stress in rat brain.

In vivo synthesis of a stress protein (SP71) in response to hyperthermia was examined in brain and several other tissues from rats ranging in age from 1 day to 25 weeks old. The synthesis of SP71 was increased dramatically by hyperthermia at all ages in all tissues examined except brain. We were unable to detect any increase in SP71 synthesis in brain due to hyperthermia until the rats were more than 2 weeks old. SP71 synthesized by the cerebral microvasculature in response to the trauma of tissue slicing has previously been reported to show a similar requirement for postnatal development. The onset of the increase in synthesis of SP71 in response to either mild hyperthermia or mechanical trauma correlates with the structural and functional maturation of the cerebral microvasculature and the blood-brain barrier.

Age Factors↗
PubMed1983

Induction of a stress protein in developing cell cultures of the rat cerebellum.

We examined the ability of developing cerebellar cell cultures to synthesize a 71,000 MW stress protein (SP71) in response to heat shock and Cd2+ treatment. The induction of SP71 synthesis appeared to be dependent on both the age of the culture and the stressor used. Heat shock induced SP71 synthesis in freshly prepared cells and in cell cultures at each age examined, whereas Cd2+ was effective only in cultures at 7 days of age and older. These findings are discussed with reference to the development of various cell types in these cultures.

Animals↗
PubMed1983

Characterization of the synthesis and accumulation of a 71-kilodalton protein induced in rat tissues after hyperthermia.

Tissues of rats subjected to brief hyperthermic shock were examined by two-dimensional gel electrophoresis for the synthesis and accumulation of a 71-kdalton stress-induced protein (P71). Tissues of 6-week-old rats, killed immediately or 30 min after hyperthermic shock, contained little or no P71. However, in all tissues tested, synthesis and accumulation of P71 was easily detected as early as 2.5 h after hyperthermic shock. The synthesis of P71 was markedly reduced by 1 and 2 days postshock, while the concentration of P71 in all tissues remained high up to 2 days postshock. After 4 days, P71 accumulation was not detected in brain and was reduced in other tissues; at 8 and 16 days after hyperthermic shock, P71 was still detectable but at ever diminishing amounts in heart, lung, liver, spleen, adrenals, and bladder. The subcellular distribution of P71 in brain and liver was determined 2.5 h and 1 and 2 days after hyperthermic shock. The soluble fractions of brain and liver had the greatest enrichment of P71 at each of these times. These results indicate that P71 is a soluble protein which may be present in at least some tissues of unstressed rats and that relatively high concentrations of P71 are found in most tissues after trauma. The increased synthesis of P71 is transient (persisting for less than 24 h after induction), suggesting that P71 is only slowly degraded in these tissues.

Animals↗
PubMed1981

Protein and RNA synthesis in cerebral microvessels: a radioautographic study.

The distribution of protein and ribonucleic acid (RNA) synthesized by telencephalon slices was determined by radioautography at the light microscope level. Previous studies had shown that, in telencephalon slices, the cells associated with the cerebral microvasculature were synthesizing protein at very high rates compared to other cerebral cells such as neurons. In this study, therefore, particular emphasis was placed on the distribution of newly synthesized protein and RNA among the various cell types of the microvasculature. Rat telencephalon slices were incubated with either [3H] leucine or [3H] uridine for 1 h. The 3H-protein that was found in association with microvessels was present in endothelial cells, pericytes and smooth muscles cells. There was also extensive labeling of cellular processes adjacent to the abluminal side of the basement membrane and extending as far as 15 micrometer from the lumen. The latter processes may have been astrocyte glial projections. All [3H] RNA found associated with microvessels was, however, restricted to endothelial cells and pericytes. This data is discussed in relation to the induction of a 71,000 dalton protein which occurs within minutes of the preparation of tissue slices, and requires the synthesis of new RNA.

Animals↗
PubMed1981

Trauma-induced protein in rat tissues: a physiological role for a "heat shock" protein?

Hyperthermic shock induces the synthesis of a novel protein (P71) in many rat tissues in vivo. In incubated rat tissue slices P71 is the major protein synthesized even though it is undetectable in the tissues of a normal, unstressed rat. P71 is "heat shock" protein, and it may be induced in vivo by stimuli other than hyperthermia. These results indicate that caution must be used in studies of protein synthesis in tissue explants, since the pattern of proteins synthesized by rat tissue slices is characteristic of stressed tissue.

Animals↗
PubMed1981

Cellular responses to stress: comparison of a family of 71--73-kilodalton proteins rapidly synthesized in rat tissue slices and canavanine-treated cells in culture.

Cultured rat embryo cells exposed to the L-arginine analogue L-canavanine rapidly accumulated a major 71 kilodalton polypeptide and several minor ones (110, 95, 88, and 78 kilodaltons). Canavanine-treated cultures contained elevated levels of translatable mRNA encoding P71, and the stimulated synthesis of this protein was blocked by actinomycin D, suggesting that P71 is inducible. Rat embryo cells maintained under routine culture conditions synthesized only trace amounts of P71; however, they accumulated an abundant 73 kilodalton protein that was closely related to P71. No kinetic evidence of a precursor-product relationship between P73 and P71 was found. The peptide map of P71 from cultured cells was identical to the map of proteins with the same electrophoretic mobility isolated from incubated slices of rat telencephalon. Previous studies (White, '80a, b, c) have shown that the latter proteins are rapidly synthesized by cells associated with cerebral microvessels in incubated brain slices, but are not detectable in vivo. Herein we present evidence that the synthesis of P71 is not unique to brain slices. Incubated slices of heart, lung, thymus, kidney, spleen, and liver all accumulated an abundant 71 kilodalton size class. The peptide maps of P71 obtained from brain, heart, lung and thymus tissue were similar. The stimulated synthesis of P71 in brain, heart, and lung slices was inhibited strongly by the addition of actinomycin D at the start of incubation. The 71-73 kilodalton proteins of canavanine-treated rat embryo cells and incubated slices from seven different organs were compared in detail on two-dimensional polyacrylamide gels. Eight charge variants were detected in extracts of lung, spleen, and thymus tissue, four in liver and heart, three in kidney, and two different pairs of variants in extracts of brain tissue and cultured cells. The possible significance of the rapid synthesis of a similar small set of proteins in tissue slices and cultured cells in response to a variety of physical, chemical, and biological stimuli is discussed in terms of cellular responses to traumatic injury and metabolic stress.

Animals↗
PubMed1981

Protein synthesis by astrocytes in primary cultures.

Protein synthesis, measured as leucine incorporation into acid-precipitable proteins, was determined in astrocytes in primary cultures obtained from the cerebral hemispheres of newborn mice. As can be expected for eucaryotic, ribosomal protein synthesis, the incorporation was almost completely inhibited by cycloheximide (0.01 mM), but unaffected by chloramphenicol (0.03 mM). The rate of synthesis, measured during exposure to a high (0.8 mM) concentration of leucine was 5.4 nmol/hr/mg protein in mature (i.e., at least 4-week-old) cultures. This value is at least twice as high as the protein synthesis rates reported for the adult brain in vivo, suggesting that a very considerable part of the protein synthesis in the adult brain may take place in astrocytes. The molecular weight distribution of the synthesized proteins was determined by polyacrylamide gel electrophoresis, demonstrating synthesis of at least 50 different polypeptides, ranging in molecular weight between 190,000 and 27,000 daltons. The pattern of the synthesized proteins underwent considerable alteration with age in young cultures in which the total content of protein was still increasing, but it was remarkably stable after the age of two weeks. Exposure to dibutyryl cyclic AMP, which is known to alter morphology, content of glial fibrillary acidic protein (GFA), and activities of certain enzymes in the cultures in the cultured astrocytes, caused marked alterations in the pattern of the synthesized proteins.

Animals↗
PubMed1981

Microvessels isolated from rat brain: localization of astrocyte processes by immunohistochemical techniques.

Microvascular networks were isolated from rat telencephalon by density gradient centrifugation. The vessels prepared were characterized morphologically at the light and electron microscope level and immunohistochemically by the localization of glutamine synthetase and glial fibrillary acidic protein, two proteins found almost exclusively in astrocytes. The vast majority of the vessels prepared contained more than just endothelial cells surrounded by a basement membrane. Many arterioles were found still retaining their smooth muscle cells. Pericytes were found in association with most of the venules and many of the capillaries. Astrocyte processes remained attached to most of the microvessels. These results show that vessels prepared from rat brain still maintain most of their complex intercellular contacts and must be viewed as a heterogeneous network of cells.

Animals↗
PubMed1981

The induction of "stress" proteins in organ slices from brain, heart, and lung as a function of postnatal development.

The proteins synthesized in vitro by rat brain, heart, and lung slices were compared by two-dimensional polyacrylamide gel electrophoresis. A protein, P71, which is related to one of the heat shock proteins induced in many cultured cells by hyperthermia and other harsh conditions, was the major protein synthesized by all slices from rats 3 weeks old and older. In vivo synthesis of P71 was not detected in brain, heart, or lung from these animals nor was there any detectable Coomassie brilliant blue-stained protein coinciding with P71 on the gels. P71 thus appears to be a minor protein species in normal unstressed brain, heart, and lung. While both heart and lung slices synthesized large quantities of P71 at all stages of postnatal development, brain slices synthesized little, if any, P71 until 3 weeks postnatal. There was a dramatic decrease in protein synthesis in all tissue slices during postnatal development. During this decrease, the relative abundance of newly synthesized P71 remained almost constant in heart and lung slices, but the relative abundance of P71 increased by approximately 50-fold in brain slices. The cells synthesizing P71 in brain slices were enriched in a microvascular fraction. The increase in P71 synthesis by these cells, occurring between the 3nd and 3rd postnatal week, coincides with the final maturation of brain capillaries and the blood-brain barrier.

Animals↗