scholarly journals MODE OF ACTION OF THYROXINE UPON SUCCINIC DEHYDROGENASE SYSTEM OF RAT TISSUE HOMOGENATES IN VITRO

1957 ◽  
Vol 4 (4) ◽  
pp. 236-247
Author(s):  
KIYOSHI YAMAMOTO ◽  
YUHSUKE SUGISAWA
Keyword(s):  
Mode Of Action ◽  
Succinic Dehydrogenase ◽  
Tissue Homogenates ◽  
Dehydrogenase System ◽  
Rat Tissue

scholarly journals The Mode of Action of Dibutyryl Adenosine 3′,5′-Monophosphate on Bone Tissue in Vitro

1971 ◽  
Vol 246 (22) ◽  
pp. 6770-6775
Author(s):  
Johannes N.M. Heersche ◽  
Susan A. Fedak ◽  
G.D. Aurbach
Keyword(s):  
Bone Tissue ◽  
Mode Of Action

Cytologic detection of Toxoplasma gondii in the cerebrospinal fluid of a dog and in vitro isolation of a unique mouse-virulent recombinant strain

2021 ◽  
pp. 104063872199668
Author(s):  
Waléria Borges-Silva ◽  
Mariana M. Rezende-Gondim ◽  
Gideão S. Galvão ◽  
Daniele S. Rocha ◽  
George R. Albuquerque ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Toxoplasma Gondii ◽  
Recombinant Strain ◽  
Neospora Caninum ◽  
Clinical Signs ◽  
Species Identity ◽  
Cytologic Examination ◽  
Pcr Rflp ◽  
Tissue Homogenates

Parasites resembling Neospora caninum or Toxoplasma gondii were detected by cytologic examination of cerebrospinal fluid (CSF) from a dog with neurologic disease. The dog became severely ill and was euthanized. Canine tissue homogenates were used for direct parasite isolation in cell culture, bioassay in 2 mouse lineages, and PCR. T. gondii was isolated in monkey kidney cells, and species identity was confirmed by PCR. Inoculated parasites were highly virulent for mice, which developed clinical signs and were euthanized immediately. PCR-RFLP for T. gondii using the cultured isolate (TgDgBA22) was conducted with 12 genetic markers, and a unique recombinant strain was identified. Detection of T. gondii by CSF cytology, although described in humans, had not been reported previously in dogs, to our knowledge, and was crucial for the diagnosis of toxoplasmosis in the examined dog.

scholarly journals Calcium-sensitivity of inositol 1,4,5-trisphosphate metabolism in exocrine cells from the avian salt gland

1992 ◽  
Vol 282 (3) ◽  
pp. 703-710 ◽  
Author(s):  
J P Hildebrandt ◽  
T J Shuttleworth
Keyword(s):  
Substrate Concentration ◽  
Inositol Phosphates ◽  
Receptor Activation ◽  
Dependent Manner ◽  
Salt Glands ◽  
Concentration Dependent Manner ◽  
Intact Cells ◽  
Exocrine Cells ◽  
Tissue Homogenates

The generation of inositol phosphates upon muscarinic-receptor activation was studied in [3H]inositol-loaded exocrine cells from the nasal salt glands of the duck Anas platyrhynchos, and the metabolism of different inositol phosphates in vitro was studied in tissue homogenates, with particular reference to the possible interaction of changes in intracellular [Ca2+] ([Ca2+]i) with the metabolic processes. In intact cells, there was a rapid (within 15 s) generation of Ins(1,4,5)P3 and Ins(1,3,4,5)P4, followed by an accumulation of their breakdown products, Ins(1,3,4)P3 and inositol bis- and monophosphates. Ca(2+)-sensitivity of the Ins(1,4,5)P3 3-kinase was demonstrated in tissue homogenates, with the rate of phosphorylation increasing 2-fold at free Ca2+ concentrations greater than 1 microM. However, addition of calmodulin or the presence of the calmodulin inhibitor W-7 (up to 100 microM) had no effect. 3-Kinase activity increased proportionally with the initial Ins(1,4,5)P3 concentration up to 1 microM, but a 10-fold higher substrate concentration produced only a doubling in the phosphorylation rate. Ins(1,3,4,5)P4 was dephosphorylated to Ins(1,3,4)P3, which accumulated in the homogenate assays as well as in intact cells. Depending on its concentration, Ins(1,3,4)P3 was phosphorylated [in part to Ins(1,3,4,6)P4] or dephosphorylated. To investigate the Ca(2+)-sensitivity of the 3-kinase in intact cells, excess quin2 was used to buffer the receptor-mediated transient changes in [Ca2+]i in [3H]inositol-loaded cells. These experiments revealed that increasing [Ca2+]i from less than 100 to approx. 400 nM (i.e. within the physiological range) has no effect on the partitioning of Ins(1,4,5)P3 metabolism (phosphorylation versus dephosphorylation) and on the accumulation of Ins(1,4,5)P3 and Ins(1,3,4,5)P4. This indicates that activation of the 3-kinase by physiologically relevant Ca2+ concentrations may not play a major role in the generation of Ins(1,3,4,5)P4 signals upon receptor activation in these cells. The latter are mainly achieved by the receptor-mediated increase in Ins(1,4,5)P3 in the cell and its phosphorylation by the 3-kinase in a substrate-concentration-dependent manner.

Inhibition in vitro of 4-methyl-coumaryl-7-amide peptide hydrolysis by peptidases in cancer tissue homogenates

1986 ◽  
Vol 14 (5) ◽  
pp. 875-876
Author(s):  
ANIL VASISHTA ◽  
PETER R. BAKER ◽  
PAUL E. PREECE ◽  
ROBERT A. B. WOOD ◽  
ALFRED CUSCHIERI
Keyword(s):  
Cancer Tissue ◽  
Peptide Hydrolysis ◽  
Tissue Homogenates

Inhibition of Adenosine Triphosphatases in Vitro by Silver Nitrate and Silver Sulfadiazine

1984 ◽  
Vol 3 (1) ◽  
pp. 37-42 ◽  
Author(s):  
B. R. Nechay ◽  
J. P. Saunders
Keyword(s):  
Silver Nitrate ◽  
Aqueous Suspension ◽  
Human Kidney ◽  
Silver Sulfadiazine ◽  
Constant Concentration ◽  
Inhibitory Potency ◽  
Adenosine Triphosphatases ◽  
Tissue Homogenates ◽  
Atpase Inhibition

Inhibition of adenosine triphosphatase (ATPase) by silver nitrate (AgNO3) in vitro was studied in microsomal fractions or tissue homogenates of canine brain and kidney and human kidney. In microsomal fractions, AgNO3 was an indiscriminate inhibitor of ouabain-sensitive (Na+ + K+ ATPase) and ouabain-insensitive (Mg2+ ATPase) activities, with 50% inhibition obtaining at concentrations on the order of 10–7 to 10–6 M. Changing the concentrations of Na+, K+, H+, Mg2+, and ATP did not alter the fractional inhibition of Na+ + K+ ATPase by a constant concentration of AgNO3. An aqueous suspension of silver sulfadiazine had an inhibitory potency similar to AgNO3. It was concluded that silver gives a different pattern of Na+ + K+ ATPase inhibition than other metallic inhibitors of the enzyme so far examined.

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