In Vivo Behavior of Multiparticulate Versus Single-Unit Dose Formulations

1994 ◽  
pp. 333-355 ◽  
Author(s):  
George Digenis
Keyword(s):  
Single Unit ◽  
Unit Dose

Single-unit pH-sensitive double-barreled microelectrodes for extracellular use

1984 ◽  
Vol 57 (3) ◽  
pp. 907-912
Author(s):  
S. Javaheri ◽  
A. De Hemptinne ◽  
I. Leusen
Keyword(s):  
Direct Current ◽  
Single Unit ◽  
Extracellular Fluid ◽  
Ph Sensitive ◽  
Current Potential

The purpose of this study is to systematically describe the construction of pH-sensitive double-barreled microelectrodes for extracellular use. The most important advantages of these microelectrodes are as follows: the reference and the pH barrels are next to each other, and therefore the measured pH is not affected by asymmetric or slowly spreading direct current potential. The diameter of the tip of the microelectrodes is between 7 and 35 micron. These pH-sensitive microelectrodes are generally stable and Nernstian. They can be used repeatedly both in vivo and in vitro to measure tissue extracellular fluid pH. Some applications are described.

Extracellular Single-Unit Recording and Neuropharmacological Methods

2015 ◽  
Author(s):  
William L. Coleman ◽  
R. Michael Burger
Keyword(s):  
Single Unit ◽  
Extracellular Recording ◽  
Electrode Position ◽  
Single Unit Recording ◽  
Recording Equipment ◽  
Unit Recording ◽  
Laboratory Equipment ◽  
Histological Confirmation ◽  
Signal Isolation

Small biogenic changes in voltage such as action potentials in neurons can be monitored using extracellular single unit recording techniques. This technique allows for investigation of neuronal electrical activity in a manner that is not disruptive to the cell membrane, and individual neurons can be recorded from for extended periods of time. This chapter discusses the basic requirements for an extracellular recording setup, including different types of electrodes, apparatus for controlling electrode position and placement, recording equipment, signal output, data analysis, and the histological confirmation of recording sites usually required for in vivo recordings. A more advanced extracellular recording technique using piggy-back style multibarrel electrodes that allows for localized pharmacological manipulation of neuronal properties is described in detail. Strategies for successful signal isolation, troubleshooting advice such as noise reduction, and suggestions for general laboratory equipment are also discussed.

scholarly journals Large-Scale Chronically Implantable Precision Motorized Microdrive Array for Freely Behaving Animals

2008 ◽  
Vol 100 (4) ◽  
pp. 2430-2440 ◽  
Author(s):  
Jun Yamamoto ◽  
Matthew A. Wilson
Keyword(s):  
Single Unit ◽  
Large Scale ◽  
Neural Circuits ◽  
Brain Regions ◽  
Unit Recording ◽  
Chronic Recording ◽  
Large Numbers ◽  
Freely Behaving

Multiple single-unit recording has become one of the most powerful in vivo electro-physiological techniques for studying neural circuits. The demand has been increasing for small and lightweight chronic recording devices that allow fine adjustments to be made over large numbers of electrodes across multiple brain regions. To achieve this, we developed precision motorized microdrive arrays that use a novel motor multiplexing headstage to dramatically reduce wiring while preserving precision of the microdrive control. Versions of the microdrive array were chronically implanted on both rats (21 microdrives) and mice (7 microdrives), and relatively long-term recordings were taken.

scholarly journals Relative oral efficacy and acute toxicity of hydroxypyridin-4-one iron chelators in mice [see comments]

Blood ◽  
1990 ◽  
Vol 76 (11) ◽  
pp. 2389-2396
Author(s):  
JB Porter ◽  
J Morgan ◽  
KP Hoyes ◽  
LC Burke ◽  
ER Huehns ◽  
...  
Keyword(s):  
Acute Toxicity ◽  
Intraperitoneal Administration ◽  
Safety Margin ◽  
Oral Route ◽  
Free Form ◽  
Iron Chelators ◽  
Lipid Solubility ◽  
Unit Dose ◽  
Therapeutic Safety

The relationship between the oral efficacy and the acute toxicity of hydroxypyridin-4-one iron chelators has been investigated to clarify structure-function relationships of these compounds in vivo and to identify compounds with the maximum therapeutic safety margin. By comparing 59Fe excretion following oral or intraperitoneal administration of increasing doses of each chelator to iron-overloaded mice, the most effective compounds have been identified. These have partition coefficients (Kpart) above 0.3 in the iron-free form with a trend of increasing oral efficacy with increasing Kpart values (r = .6). However, this is achieved at a cost of increasing acute toxicity, as shown by a linear correlation between 59Fe excretion increase per unit dose and 1/LD50 (r = .83). A sharp increase in the LD50 values is observed for compounds with Kpart values above 1.0, suggesting that such compounds are unlikely to possess a sufficient therapeutic safety margin. Below a Kpart of 1.0, acute toxicity is relatively independent of lipid solubility. All the compounds are less toxic by the oral route than by the intraperitoneal route, although iron excretion is not significantly different by these two routes. At least five compounds (CP51, CP94, CP93, CP96, and CP21) are more effective orally than the same dose of intraperitoneal desferrioxamine (DFO) (P less than or equal to .02) or orally administered L1(CP20) (P less than or equal to .02).

scholarly journals Single-unit transfusions of RBC enzymatically converted from group B to group O to A and O normal volunteers

Blood ◽  
1991 ◽  
Vol 77 (6) ◽  
pp. 1383-1388 ◽  
Author(s):  
LL Lenny ◽  
R Hurst ◽  
J Goldstein ◽  
LJ Benjamin ◽  
RL Jones
Keyword(s):  
Single Unit ◽  
Small Volume ◽  
Survival Times ◽  
Chronic Anemia ◽  
Group A ◽  
Alpha Galactosidase ◽  
Group B ◽  
Sustained Increase

Abstract Full-unit transfusions of RBC enzymatically converted from group B to group O by treatment with alpha-galactosidase (ECO RBC) to group O and A normal healthy individuals exhibit excellent in vivo survival times (24-hour survival 95.1% +/- 2.3%, T50 36.9 +/- 4.6 days). These results confirm our earlier findings describing ECO RBC in vitro viability and normal in vivo survival time after small-volume infusions. No significant increase in pretransfusion anti-B titer or score is observed in either group O or A subjects provided that sufficient enzyme is used to treat the cells: Cells transfused to group O recipients require higher levels of enzyme (185 to 200 U/mL RBC) than those infused to group A (90 U/mL RBC). Two separate single-unit transfusions of ECO RBC to one group O recipient (4.5 months apart) also survived normally (24-hour survival 96% and 92%, T50 40 and 36 days) and did not increase preexisting anti-B levels in this subject. ECO RBC were not agglutinated or lysed by recipient sera before or after transfusion. Similarly, no antibody development to the alpha- galactosidase used in cell treatment (and washed from the product before transfusion) could be detected in any subject. The sustained increase in hemoglobin levels after transfusion of ECO RBC suggests that this product will be useful in treatment of acute and chronic anemia.

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