Brain blood flow, studying

Mathis, C. A., T. Sargent, and A. T. Shulgin. 1985. Iodine-122 labeled amphetamine derivatives with potential for PET brain blood-flow studies. 

Lassen NA and Ingvar DH (1980). Blood flow studies in the aging normal brain and in senile dementia. Aging of the brain and dementia. Aging, 13, 91-98. 

CDP-choline Choline donor Endogenous nucleotide APOE Retrospective Prospective Genotype dependent Genotype dependent Cognition Brain blood flow Brain mapping Bio-chemistry Replicated in two studies... 

Another class of commonly used radiopharmaceuticals measure regional brain blood flow. In PET, [ 0]H20 is used as a radiopharmaceutical and in SPECT, [99mjc]HMPAQ, [99> Tc]ECD, or [ 9 ] /]p are used. Studies of patients with AD with the use of these radiopharmaceuticals have been thoroughly reviewed elsewhere [e,g, 34-36] and it is out of the scope of this chapter to further discuss these studies. 

Tcm Brain, heart, lung, thyroid, gall bladder, skin, lymph node, bone, liver, spleen, and kidney imaging Blood flow studies... 

The meta-orientation of the two methoxyl groups does, however, greatly increase the susceptibility of the aromatic ring to electrophilic attack. This is one of the three possible meta-dimethoxy substituted amphetamines, and it is the best studied one in the pursuit of potential radio-halogen substituted brain blood-flow agents. This strategy is discussed under 1DNNA the other two meta-compounds are discussed under 3,4-DMA. 

Several of the alpha-ethyl analogues of ARIADNE were N,N-dialky lated, and were target compounds for halogenation with radio-iodine or radio-fluorine, for evaluation as potential brain blood-flow indicators. In these studies, all examples followed a common flow diagram. The reaction of the appropriate benzaldehyde... 

As an alternative to N-isopropyl-p-[123I]-iodoamphetamine, an agent used to study regional brain metabolism and perfusion, de Bruin et al.331 have proposed 201T1-DDTC as a replacement. A comparison of radioamphetamine and 201T1-DDTC showed that both radiopharmaceuticals are equally suitable for blood flow studies of the brian. 

Surgeons are concerned with brain blood flow to patients undergoing cardiopulmonary bypass surgery. An intensive study by Chow et al. was conducted where blood flows were restricted to patients from age 2 weeks to over 20 years [48]. Near-IR was used to correlate blood flow rate with NIR spectra of the brain. Flows of 0.6, 1.2, and 2.4 L/mVmin-1 were used. Their results showed that flow was related to mean arterial pressure, but did not correspond to pulsatility. This was interesting in that pulse rate is often used as a diagnostic to assure sufficient blood flow to the brain during surgery. 

When normal subjects were shown film clips that provoked the emotions of happiness, fear, or disgust, oxygen-15 water studies of regional brain blood flow showed increased neuronal blood flow in the primary and secondary visual cortex, as well as in limbic regions [Paradiso et al.. Am. J. Psychiatry 154(3) 384-389,1997]. 

In the area of psychedelic drugs, the value of 2,5-DMA is mainly in its role as a precursor to the preparation of materials that can come from a direct electrophilic attack on the activated 4-position. These uses can be found under things such as DOB and DOI and DON. The radio-halogenation of N-substituted homologues of 2,5-DMA with hypoiodite or hypofluorite is part of an extensive study undenway in the search for radio-labeled brain blood flow agents. The... 

This simple analysis is appropriate at low count rates when random events are negligible, but at higher rates the advantage must be defined in terms of improvement in statistical noise as embodied in the parameter noise-equivalent counts (NEC). It is found that there is an NEC gain with the 3D mode over the whole range of count rates. For brain studies this varies from about a factor of 5 at low rates (for example, in receptor binding studies with relabelled compounds) to about 3 at high rates (such as are encountered in blood flow studies with i- O-labelled water). 

In the first of these studies, the researchers identified the areas of the brain that are associated with normal sadness. They asked volunteer subjects to think about some very sad personal experiences - and about some emotionally neutral experiences - while their brains were being imaged in a PET scanner. When thinking about the sad experiences, the volunteers reported feeling intense sadness, and many of them became tearful. The PET scans showed the changes in brain activity that accompanied these sad feelings. They demonstrated increased blood flow in the limbic system - a part of the brain that is involved in the control of emotion - and decreased blood flow in parts of the brain that are involved in the control of attention. 

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