Effects of Mannitol and Iohexol Infusions on the Renal Cortical Blood Flow in Dehydrated Mice

In vivo fluorescence microscopy was used in experimental studies of renal cortical microcirculation in mice. The effects of intravenous infusions of equimolar concentrations of mannitol and iohexol were studied in normal lean mice and obese/hyperglycemic mice after dehydration overnight. All infusions produced marked effects in distribution and velocity of renal cortical blood flow. Initially increased blood flow was seen in a number of capillaries after infusion of both mannitol and iohexol, and renal cortical blood flow was inhomogeneous for different capillaries. A significantly (p<0.05) larger number of capillaries with decreased blood flow, within the first minutes after start of infusion, was observed after infusion of iohexol to normal mice when the animals had been dehydrated overnight. Our results indicate that the minor adverse effects on renal cortical blood flow caused by the infusion of contrast medium are potentiated by dehydration.

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In Vivo Fluorescence Microscopy of Microcirculation in the Renal Cortex of Mice

Acta Radiologica ◽

10.1177/028418519403500216 ◽

1994 ◽

Vol 35 (2) ◽

pp. 176-181 ◽

Cited By ~ 3

Author(s):

B. Högström ◽

S.-O. Hietala ◽

P. Rooth

Keyword(s):

Blood Flow ◽

Fluorescence Microscopy ◽

Renal Cortex ◽

Experimental Studies ◽

Cortical Blood Flow ◽

In Vivo Fluorescence ◽

Streptozotocin Induced Diabetes ◽

Renal Cortical Blood Flow ◽

Increased Blood Flow

In vivo fluorescence microscopy was used in experimental studies of renal cortical microcirculation in mice. The effects of i.v. infusions of mannitol and iohexol were studied in normal and obese/hyperglycemic mice and in mice with streptozotocin-induced diabetes mellitus. All infusions produced marked effects on the distribution and velocity of cortical blood flow with no differences between iohexol and mannitol. The renal cortical blood flow was inhomogeneous regarding different capillaries and there was an initial rise in the number of capillaries with increased blood flow after infusions of both mannitol and iohexol. The infusions of contrast medium were initially followed by a significantly larger number of capillaries with decreased blood flow in the obese/hyperglycemic mice (p < 0.05) than in the diabetic and nondiabetic mice. The variations in obese/hyperglycemic groups were, however, large. The effects were the same in normal and diabetic animals.

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In Vivo Fluorescence Microscopy of Microcirculation in the Renal Cortex of Mice

Acta Radiologica ◽

10.1177/028418519303400214 ◽

1993 ◽

Vol 34 (2) ◽

pp. 174-178 ◽

Cited By ~ 5

Author(s):

B. Högstrωm ◽

P. Rooth ◽

O. Sunnegårdh ◽

S.-O. Hietala

Keyword(s):

Blood Flow ◽

Fluorescence Microscopy ◽

Contrast Media ◽

Renal Cortex ◽

Experimental Studies ◽

Cortical Blood Flow ◽

In Vivo Fluorescence ◽

Renal Cortical Blood Flow ◽

Increased Blood Flow

In vivo fluorescence microscopy was used for experimental studies of renal cortical microcirculation in 46 mice. The cortical circulation was studied after i.v. infusions of mannitol of various osmolalities as well as nonionic low osmolar (iohexol) and ionic high osmolar (metrizoate) contrast media. All infusions produced an increase in the number of capillaries with increased blood flow, significantly more pronounced after the infusion of iohexol, metrizoate and mannitol 1.46 mol/l than after the infusion of mannitol 0.3 mol/l. However, the renal cortical blood flow was inhomogeneous with respect to different capillaries. While the blood flow was increased in some capillaries it was to some extent simultaneously decreased in others, significantly more after infusion of metrizoate than after infusion of mannitol 0.3 mol/l.

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In Vivo Fluorescence Microscopy of Microcirculation in the Renal Cortex of Mice

Acta Radiologica ◽

10.1177/028418519303400516 ◽

1993 ◽

Vol 34 (5) ◽

pp. 500-504 ◽

Cited By ~ 3

Author(s):

B. Högström ◽

S.-O. Hietala ◽

P. Rooth

Keyword(s):

Blood Flow ◽

Fluorescence Microscopy ◽

Cyclosporin A ◽

Experimental Studies ◽

Cortical Blood Flow ◽

In Vivo Fluorescence ◽

Renal Cortical Blood Flow ◽

The Difference ◽

Increased Blood Flow

In vivo fluorescence microscopy was used for experimental studies of the renal cortical microcirculation in normal mice and in mice pretreated with the nephrotoxic drug cyclosporin A. The cortical circulation was studied after i.v. infusions of a nonionic low osmolar contrast medium (iohexol) and after infusions of mannitol. All infusions produced marked effects on the distribution and velocity of cortical blood flow with no differences between iohexol and mannitol. The renal cortical blood flow was inhomogeneous regarding different capillaries and there was an initial rise in the number of capillaries with increased blood flow after infusions of both mannitol and iohexol. There was simultaneously an increased number of capillaries with decreased blood flow following all infusions. The decreased blood flow after infusion of iohexol was more pronounced when the animals had been pretreated with cyclosporin A. The difference was only significant (p < 0.05) during a short part of the observation period of 30 min, but it may indicate that kidneys previously exposed to cyclosporin A are more susceptible to infusions of iohexol.

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In Vivo Fluorescence Microscopy of Microcirculation in the Renal Cortex of Mice

Acta Radiologica ◽

10.1177/028418519303400517 ◽

1993 ◽

Vol 34 (5) ◽

pp. 505-509 ◽

Cited By ~ 2

Author(s):

B. Högström ◽

S.-O. Hietala ◽

P. Rooth

Keyword(s):

Blood Flow ◽

Fluorescence Microscopy ◽

Renal Cortex ◽

Experimental Studies ◽

Initial Increase ◽

Cortical Blood Flow ◽

In Vivo Fluorescence ◽

Renal Cortical Blood Flow ◽

Increased Blood Flow

In vivo fluorescence microscopy was used for experimental studies of the renal cortical microcirculation in mice. The effects of i.v. infusions of mannitol and iohexol were studied in untreated mice as well as in mice after temporary renal ischemia. All infusions produced marked effects on the distribution and velocity of cortical blood flow with no differences between iohexol and mannitol. The renal cortical blood flow was inhomogeneous with respect to different capillaries and there was an initial rise in the number of capillaries with increased blood flow after infusions of both mannitol and iohexol. There was an initial increase in the number of capillaries with a decreased blood flow following 30 min of ischemia. This increase was reduced by both types of infusions, suggesting a beneficial effect on renal cortical blood flow. Neither mannitol nor contrast medium exhibited any adverse effects in ischemic kidneys that would be likely to affect renal function. However, 5 min after the infusions there was an increasing number of capillaries with decreased blood flow in all groups.

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Effects of Isosmolar Contrast Media on the Renal Cortical Blood Flow in Mice

Acta Radiologica ◽

10.1177/02841851960373p232 ◽

1996 ◽

Vol 37 (3P2) ◽

pp. 587-590 ◽

Cited By ~ 1

Author(s):

B. Högström ◽

S.-O. Hietala ◽

P. Rooth

Keyword(s):

Blood Flow ◽

Contrast Media ◽

Contrast Medium ◽

Experimental Studies ◽

Initial Increase ◽

Cortical Blood Flow ◽

Renal Cortical Blood Flow ◽

The Difference ◽

Increased Blood Flow

Purpose: In vivo fluorescence microscopy was used in experimental studies of renal cortical microcirculation in mice. The effects of i.v. infusion of a nonionic monomeric contrast medium (iohexol), a nonionic dimeric contrast medium (iodixanol), and mannitol of corresponding osmolalities were studied. Results: All infusions produced marked effects on the distribution and velocity of renal cortical blood flow. Renal cortical blood flow was inhomogeneous as regards the different capillaries. There was an initial rapid rise in the blood flow in some capillaries after all infusions, while decreased flow was seen in other capillaries. The initial increase in renal cortical blood flow (RCBF) was significantly (p<0.05) more pronounced after infusion of iohexol than after infusion of mannitol 0.69 mol/l. In all other respects, the effects of contrast media on RCBF were the same as the effects of mannitol solutions with a corresponding osmolality. The effects of each contrast medium were the same as those of mannitol of corresponding osmolality. In the capillaries showing increased blood flow, the peak value was encountered slightly later after the infusion of iodixanol than after the infusion of iohexol. This was considered to be related to differences in viscosity rather than osmolality. Conclusion: The difference in osmolality between iodixanol and iohexol is of no significance with regard to their effects on RCBF.

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In Vivo Fluorescence Microscopy of Microcirculation in the Renal Cortex of Mice

Acta Radiologica ◽

10.1177/028418519303400213 ◽

1993 ◽

Vol 34 (2) ◽

pp. 168-173 ◽

Cited By ~ 6

Author(s):

B. Högström ◽

P. Rooth ◽

O. Sunnegårdh ◽

S.-O. Hietala

Keyword(s):

Blood Flow ◽

Fluorescence Microscopy ◽

Experimental Model ◽

Rating Scale ◽

Capillary Blood ◽

Capillary Blood Flow ◽

Cortical Blood Flow ◽

In Vivo Fluorescence ◽

Renal Cortical Blood Flow

An experimental model using in vivo fluorescence microscopy for studies of renal cortical blood flow was tested in 40 mice. The model was suitable for testing a wide variety of hypotheses concerning alterations in renal cortical blood flow, including the possibility of inhomogeneous capillary blood flow distribution in response to i.v. infusions. The experimental model was tested for the effects of i.v. infusion of mannitol (0.3 mol/l). Effects of anesthesia and mechanical kidney fixation on renal cortical blood flow were studied. Neuroleptic analgesia was less hazardous to the animals than pentobarbital. Due to artifacts from respiratory and peristaltic motion, it was not possible to use neuroleptic analgesia without mechanical kidney fixation. A rating scale was designed for evaluating the capillary blood flow. The correlation between repeated ratings by the same observer was 0.806 and between 2 different observers 0.59.

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