In Vitro Synthesis of Estrogen Glucuronides and Sulfates by Human Renal Tissue

1975 ◽  
Vol 53 (7) ◽  
pp. 779-783 ◽  
Author(s):  
Joyce D. Mellor ◽  
R. Hobkirk
Keyword(s):  
Renal Tissue ◽  
In Vivo Studies ◽  
Time Study ◽  
Tissue Slices ◽  
Experimental Conditions ◽  
In Vitro Synthesis ◽  
Estrone Sulfate ◽  
Layer Chromatography

17β-[6,7-3H]Estradiol (E2) was incubated with slices and homogenates of adult human renal tissue. The metabolites formed were identified by chromatography on DEAE-Sephadex, thin layer chromatography and crystallization with carrier steroids or steroid derivatives. The major metabolites formed by slices were estradiol-17-glucuronide (E217G), estrone sulfate and estradiol-3-sulfate. This is the first report of in vitro synthesis of estrogen sulfates by adult renal tissue. Minor quantities of the 3-glucuronides of estrone and estradiol were also found. An oxygen atmosphere appeared to stimulate the production of E217G. A time study with tissue slices showed similarities between the in vitro pattern of glucuronide synthesis and the excretion pattern of these compounds seen in earlier in vivo studies. Homogenates fortified with uridine diphosphoglucuronic acid formed the same pattern of glucuronide products but in lesser amounts. No sulfates were formed under these conditions. Testosterone did not act as a substrate in the experimental conditions used.

scholarly journals AN ANALYSIS OF COLLAGEN SECRETION BY ESTABLISHED MOUSE FIBROBLAST LINES

1964 ◽  
Vol 22 (1) ◽  
pp. 227-258 ◽  
Author(s):  
Burton Goldberg ◽  
Howard Green
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Mouse Fibroblast ◽  
In Vivo Studies ◽  
In Vitro Synthesis ◽  
Collagen Secretion ◽  
Golgi System ◽  
Alternative Theories

In vitro synthesis of collagen by established mouse fibroblast lines has been examined by electron microscopy. During rapid growth (log phase), when collagen could not be detected in the cultures, the cells lacked a well developed granular ergastoplasm and Golgi system. Upon cessation of growth (stationary phase), collagen accumulated in the cultures and the cells demonstrated highly developed granular and smooth ergastoplasm. Collagen appeared to be synthesized in the rough-surfaced endoplasmic reticulum and to be transported as a soluble protein to the cell surface by vesicular elements of the agranular ergastoplasm. Fusion of the limiting membranes of these vesicles with the cell membrane permitted the discharge of the soluble collagen into the extracellular space, where fibrils of two diameter distributions formed. The secretion of collagen is concluded to be of the merocrine type. Alternative theories of collagen secretion are discussed and the data for established lines compared with the results of other in vitro and in vivo studies of collagen fibrillogenesis.

Viroid RNA is accepted as a template for in vitro transcription by DNA-dependent DNA polymerase I and RNA polymerase from Escherichia coli

1982 ◽  
Vol 2 (11) ◽  
pp. 929-939 ◽  
Author(s):  
Wolfgang Rohde ◽  
Hans-Richard Rackwitz ◽  
Frank Boege ◽  
Heinz L. Sänger
Keyword(s):  
Escherichia Coli ◽  
Rna Polymerase ◽  
Dna Polymerase ◽  
Unit Length ◽  
Dna Polymerase I ◽  
Experimental Conditions ◽  
In Vitro Synthesis ◽  
Polymerase I

The RNA genome of potato spindle tuber viroid (PSTV) is transcribed in vitro into complementary DNA and RNA by DNA-dependent DNA polymerase I and RNA polymerase, respectively, from Escherichia coli. In vitro synthesis of complementary RNA produces distinct transcripts larger than unit length thus reflecting the in vivo mechanism of viroid replication. The influence of varying experimental conditions on the transcription process is studied; actinomycin D is found to drastically reduce complementary RNA synthesis from the PSTV RNA template by RNA polymerase.

scholarly journals Neuroprotective Effects of Guanosine in Ischemic Stroke—Small Steps towards Effective Therapy

2021 ◽  
Vol 22 (13) ◽  
pp. 6898
Author(s):  
Karol Chojnowski ◽  
Mikolaj Opielka ◽  
Wojciech Nazar ◽  
Przemyslaw Kowianski ◽  
Ryszard T. Smolenski
Keyword(s):  
Ischemic Stroke ◽  
Brain Ischemia ◽  
Excitatory Amino Acid ◽  
Infarct Volume ◽  
In Vivo Studies ◽  
Amino Acid Transporters ◽  
Tissue Slices ◽  
Neuroprotective Effects

Guanosine (Guo) is a nucleotide metabolite that acts as a potent neuromodulator with neurotrophic and regenerative properties in neurological disorders. Under brain ischemia or trauma, Guo is released to the extracellular milieu and its concentration substantially raises. In vitro studies on brain tissue slices or cell lines subjected to ischemic conditions demonstrated that Guo counteracts destructive events that occur during ischemic conditions, e.g., glutaminergic excitotoxicity, reactive oxygen and nitrogen species production. Moreover, Guo mitigates neuroinflammation and regulates post-translational processing. Guo asserts its neuroprotective effects via interplay with adenosine receptors, potassium channels, and excitatory amino acid transporters. Subsequently, guanosine activates several prosurvival molecular pathways including PI3K/Akt (PI3K) and MEK/ERK. Due to systemic degradation, the half-life of exogenous Guo is relatively low, thus creating difficulty regarding adequate exogenous Guo distribution. Nevertheless, in vivo studies performed on ischemic stroke rodent models provide promising results presenting a sustained decrease in infarct volume, improved neurological outcome, decrease in proinflammatory events, and stimulation of neuroregeneration through the release of neurotrophic factors. In this comprehensive review, we discuss molecular signaling related to Guo protection against brain ischemia. We present recent advances, limitations, and prospects in exogenous guanosine therapy in the context of ischemic stroke.

Action of adenosine on cyclic 3',5'-nucleotides in glomeruli

1983 ◽  
Vol 244 (6) ◽  
pp. F633-F638
Author(s):  
H. E. Abboud ◽  
T. P. Dousa
Keyword(s):  
Rat Kidney ◽  
Renal Tissue ◽  
In Vivo Studies ◽  
Camp Accumulation ◽  
Renal Circulation ◽  
Tissue Slices ◽  
Cyclic Monophosphate ◽  
Camp Levels ◽  
Dose Dependent

Recent in vivo studies indicated that adenosine has a profound effect on glomerular dynamics and renal circulation. Because its effect in nonrenal tissues is frequently mediated by adenosine 3',5'-cyclic monophosphate (cAMP), we examined adenosine's effect on cyclic nucleotides in rat kidney. Incubation of tissue slices from renal cortex or medulla with 0.1 mM adenosine resulted in marginal or no increase in cAMP. In isolated glomeruli, adenosine caused a marked and dose-dependent (10(-6) to 10(-4) M) increase in cAMP accumulation. Inosine, a deaminated metabolite of adenosine, had no effect on cAMP levels in glomeruli. No distinct effect of adenosine on cAMP was observed in cortical tubules under the same testing conditions. An increase in cAMP levels in glomeruli elicited by adenosine was blocked by theophylline, a known inhibitor of adenosine receptors. In contrast, theophylline enhanced rather than decreased the stimulation of cAMP accumulation in glomeruli by serotonin. Dipyridamole, a proposed inhibitor of cellular uptake of adenosine, did not inhibit but rather enhanced cAMP accumulation in glomeruli in response to adenosine. In the present experiments adenosine did not influence guanosine 3',5'-cyclic monophosphate levels in either glomeruli or other tested preparations of renal tissue. These results provide the first experimental evidence that adenosine stimulates cAMP accumulation in glomeruli and suggest that this effect is probably due to action on the adenosine receptor on the cell surface. Our observations raise the possibility that some of the effects of adenosine in glomerular cells may be mediated via cAMP accumulation.

scholarly journals In vitro circadian rhythms: imaging and electrophysiology

2011 ◽  
Vol 49 ◽  
pp. 103-117 ◽  
Author(s):  
Christian Beaulé ◽  
Daniel Granados-Fuentes ◽  
Luciano Marpegan ◽  
Erik D Herzog
Keyword(s):  
Mammalian Cells ◽  
In Vivo Studies ◽  
In Vitro Assays ◽  
Genetic Determinants ◽  
Experimental Conditions ◽  
Cell Synchronization ◽  
Circadian Oscillators ◽  
Circadian Pacemakers

In vitro assays have localized circadian pacemakers to individual cells, revealed genetic determinants of rhythm generation, identified molecular players in cell–cell synchronization and determined physiological events regulated by circadian clocks. Although they allow strict control of experimental conditions and reduce the number of variables compared with in vivo studies, they also lack many of the conditions in which cellular circadian oscillators normally function. The present review highlights methods to study circadian timing in cultured mammalian cells and how they have shaped the hypothesis that all cells are capable of circadian rhythmicity.

scholarly journals Mutations in the Tryptophan Operon Allow PurF-Independent Thiamine Synthesis by Altering Flux In Vivo

2007 ◽  
Vol 190 (3) ◽  
pp. 815-822 ◽  
Author(s):  
Itzel Ramos ◽  
E. I. Vivas ◽  
D. M. Downs
Keyword(s):  
In Vivo Studies ◽  
In Vitro Assays ◽  
Phosphoribosyl Pyrophosphate ◽  
High Turnover ◽  
In Vitro Synthesis ◽  
Tryptophan Operon ◽  
Metabolic Robustness ◽  
Thiamine Biosynthesis

ABSTRACT Phosphoribosyl amine (PRA) is an intermediate in purine biosynthesis and also required for thiamine biosynthesis in Salmonella enterica. PRA is normally synthesized by phosphoribosyl pyrophosphate amidotransferase, a high-turnover enzyme of the purine biosynthetic pathway encoded by purF. However, PurF-independent PRA synthesis has been observed in strains having different genetic backgrounds and growing under diverse conditions. Genetic analysis has shown that the anthranilate synthase-phosphoribosyltransferase (AS-PRT) enzyme complex, involved in the synthesis of tryptophan, can play a role in the synthesis of PRA. This work describes the in vitro synthesis of PRA in the presence of the purified components of the AS-PRT complex. Results from in vitro assays and in vivo studies indicate that the cellular accumulation of phosphoribosyl anthranilate can result in nonenzymatic PRA formation sufficient for thiamine synthesis. These studies have uncovered a mechanism used by cells to redistribute metabolites to ensure thiamine synthesis and may define a general paradigm of metabolic robustness.

scholarly journals Physico-mechanical features of barrier bicomponent membranes in abdominal surgery.

2018 ◽  
Vol 11 (1) ◽  
pp. 51-54
Author(s):  
Vyacheslav Aleksandrovich Lipatov ◽  
Dmitriy M Mutalifovich ◽  
Anna V Davydova
Keyword(s):  
Early Postoperative Period ◽  
Polymeric Film ◽  
In Vivo Studies ◽  
Surrounding Tissue ◽  
Experimental Conditions ◽  
Abdominal Organs ◽  
Symptom Complex ◽  
The Moment

Revelance. Adhesive disease is one of the terrible complications with a pronounced symptom complex of the dysfunctions of the organs of the gastrointestinal tract. The frequency of this pathology in the early postoperative period with operations on the abdominal organs reaches 11% among 19-25% of all complications. Until now, it remains relevant to search for and develop methods and tools of strengthening  the seam line and improve the tightness of interintestinal anastomoses. Therefore, the prospects of using the polymers and the development of such a scientific direction as implantology in medical practice are unlimited. Purpose. Studying the physico-mechanical features of polymer samples under the experimental conditions in vitro, in a comparative aspect. The materials. Bicomponent resorbable film implants based on cellulose polymers. The methods. Microphotography of polymeric film implants was taken with a laboratory microscope Levenhuk D320L with an increase of × 80. The thickness of the experimental samples was measured with the electronic micrometer iGaging 0-1 "/0.00005,. Membranes  10 × 10 mm were weighed with the laboratory scales. The volume and density of samples 10 × 10 mm were calculated. Determination of elasticity was carried out by fixing the angle at the moment of the integrity of the sample of the polymeric film implant in the native state. The results. It was revealed that an important feature of these implants is their bilateral structure, which ensures its more tight fixation to the damaged area and at the same time sufficient separation with the surrounding tissue. Thus, we selected samples No. 6, No. 1, which can be used for further in vivo studies. The conclusion. The use of polymeric implants is possible due to the variety of membranes in their properties and functions, which will affect the necessity and significance of the application of selected samples in experimental and clinical implantology.

In vitro and in vivo studies of new cationic Zn(II)‐benzonaphthoporphyrazines as photosensitizers for PDT

2001 ◽  
Vol 5 (8) ◽  
pp. 645-651
Author(s):  
M. Peeva ◽  
M. Shopova ◽  
U. Michelsen ◽  
D. Wöhrle ◽  
G. Petrov ◽  
...  
Keyword(s):  
In Vivo Studies

Effect of caffeine on theophyliine on cerebral blood flow response to brain activation: In vitro and in vivo studies

2005 ◽  
Vol 25 (1_suppl) ◽  
pp. S198-S198
Author(s):  
Joseph R Meno ◽  
Thien-son K Nguyen ◽  
Elise M Jensen ◽  
G Alexander West ◽  
Leonid Groysman ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Brain Activation ◽  
In Vivo Studies ◽  
Blood Flow Response ◽  
Flow Response
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