The φ-transform and applications to distribution spaces

1988 ◽  
pp. 223-246 ◽  
Author(s):  
Michael Frazier ◽  
Björn Jawerth
Keyword(s):  
Distribution Spaces

scholarly journals Direct Chemical Measurement of the λ of the Lumped Constant of the [14C]Deoxyglucose Method in Rat Brain: Effects of Arterial Plasma Glucose Level on the Distribution Spaces of [14C]Deoxyglucose and Glucose and on λ

1989 ◽  
Vol 9 (3) ◽  
pp. 304-314 ◽  
Author(s):  
Kentaro Mori ◽  
Nancy Cruz ◽  
Gerald Dienel ◽  
Thomas Nelson ◽  
Louis Sokoloff
Keyword(s):  
Plasma Glucose ◽  
Glucose Concentration ◽  
Severe Hypoglycemia ◽  
Plasma Glucose Concentration ◽  
Operational Equation ◽  
Chemical Measurements ◽  
Lumped Constant ◽  
Dg Method ◽  
Arterial Plasma ◽  
Distribution Spaces

The lumped constant in the operational equation of the 2-[14C]deoxyglucose (DG) method contains the factor λ that represents the ratio of the steady-state tissue distribution spaces for [14C]DG and glucose. The lumped constant has been shown to vary with arterial plasma glucose concentration. Predictions based mainly on theoretical grounds have suggested that disproportionate changes in the distribution spaces for [14C]DG and glucose and in the value of λ are responsible for these variations in the lumped constant. The influence of arterial plasma glucose concentration on the distribution spaces for DG and glucose and on λ were, therefore, determined in the present studies by direct chemical measurements. The brain was maintained in steady states of delivery and metabolism of DG and glucose by programmed intravenous infusions of both hexoses designed to produce and maintain constant arterial concentrations. Hexose concentrations were assayed in acid extracts of arterial plasma and freeze-blown brain. Graded hyperglycemia up to 28 m M produced progressive decreases in the distribution spaces of both hexoses from their normoglycemic values (e.g., ∼ – 20% for glucose and – 50% for DG at 28 m M). In contrast, graded hypoglycemia progressively reduced the distribution space for glucose and increased the space for [14C]DG. The values for λ were comparatively stable in normoglycemic and hyperglycemic conditions but rose sharply (e.g., as much as 9–10-fold at 2 m M) in severe hypoglycemia.

A procedure for measurement of distribution spaces in isolated fat cells

1972 ◽  
Vol 286 (1) ◽  
pp. 1-9 ◽  
Author(s):  
J. Gliemann ◽  
K. Østerlind ◽  
J. Vinten ◽  
S. Gammeltoft
Keyword(s):  
Fat Cells ◽  
Isolated Fat Cells ◽  
Distribution Spaces

Extrathyroidal Effects of Low Concentrations of Thiourea on Rainbow Trout, Salmo gairdneri

1981 ◽  
Vol 38 (10) ◽  
pp. 1283-1285 ◽  
Author(s):  
J. G. Eales
Keyword(s):  
Rainbow Trout ◽  
Chronic Exposure ◽  
Degradation Rate ◽  
Salmo Gairdneri ◽  
Low Concentrations ◽  
Direct Sensitivity ◽  
Distribution Spaces ◽  
Circulating Levels

Chronic exposure of fed immature rainbow trout (Salmo gairdneri) to a low ambient thiourea (TU) concentration did not depress circulating levels of T4 (thyroxine) or triiodothyronine, T4 degradation rate, or T4 deiodination rate indicating no significant T4 influence on thyroidal hormone output. However, TU increased the hematocrit and decreased distribution spaces for iodide and T4, indicating direct sensitivity of extrathyroidal processes to TU.Key words: thiourea, thyroxine, hematocrit, iodide metabolism, rainbow trout

scholarly journals A generalized Hankel convolution on Zemanian spaces

2000 ◽  
Vol 23 (2) ◽  
pp. 131-140
Author(s):  
Jorge J. Betancor
Keyword(s):  
Slow Growth ◽  
Hankel Convolution ◽  
Distribution Spaces

We define a new generalized Hankel convolution on the Zemanian distribution spaces of slow growth.

Impermeability of rabbit erythrocytes to prostaglandins

1975 ◽  
Vol 229 (6) ◽  
pp. 1580-1584 ◽  
Author(s):  
LZ Bito ◽  
RA Baroody
Keyword(s):  
Fatty Acids ◽  
Cell Membranes ◽  
Erythrocyte Membranes ◽  
Rabbit Erythrocyte ◽  
The Mean ◽  
Intracellular Volume ◽  
Distribution Spaces ◽  
Apparent Distribution ◽  
Initial Uptake

Washed rabbit erythrocytes were suspended in Tris-electrolyte buffer containing [3H]prostaglandin (PG) E1, F1alpha, F2alpha, or A1 and one 14C-labeled compound such as sucrose. After up to 24 h of incubation, aliquots of centrifuged, packed cells and supernatant were oxidized and the 3H and 14C samples were counted. The mean sucrose space of the packed cell was 7.4%. After 1 min the E1, F1alpha, and F2alpha spaces were 16, 15.4, and 10.0%, respectively, and showed no increase even after 24 h of incubation at either 23 or 5 degrees C. At 23 degrees C the initial (0.5 min) PGA1 and thiourea spaces were 94 and 75%, respectively, whence the PGA1, but not the thiourea, space declined, reaching 30% at 4 h. The large initial uptake of PGA1 was eliminated at 5 degrees C, while it was accentuated at pH 6.8 or at a PGA1, concentration of 10(-3) M. 14C-Labeled arachidonic, octanoic, and other non-PG fatty acids gave apparent distribution spaces of 140-300%. These results show that PG's can partition into rabbit erythrocyte membranes, but the intracellular volume of the erythrocytes is not freely accessible to these autacoids. The implications of the finding that some cell membranes are impermeable to prostaglandins are discussed.

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