Changes of blood flow in the adenohypophysis of normal and estrogen pretreated Fisher rats by tamoxifen

1989 ◽  
Vol 121 (6) ◽  
pp. 821-826 ◽  
Author(s):  
Andrzej Stawowy ◽  
Andras A. Kemeny ◽  
Jan Jakubowski
Keyword(s):  
Blood Flow ◽  
Cerebral Cortex ◽  
Cerebral Blood Flow ◽  
Arterial Pressure ◽  
Anterior Pituitary ◽  
Tamoxifen Treatment ◽  
Hydrogen Clearance Method ◽  
Pituitary Hyperplasia ◽  
F344 Rats ◽  
Hydrogen Clearance

Abstract. Blood flow was measured in the adenohypophysis and in the cerebral cortex of female F344 rats over a period of 90 min using the hydrogen clearance method. Tamoxifen, 1 mg/kg, administered iv reduced the blood flow in the adenohypophysis by 35%, whereas cerebral blood flow and arterial pressure remained unchanged. Seven days sc treatment with tamoxifen (1 mg/kg daily) had no demonstrable effect on blood flow. Anterior pituitary hyperplasia was induced in 15 rats with diethylstilbestrol containing implants. These rats responded to 7 days of sc tamoxifen treatment by 30% increase in adenohypophyseal blood flow. These results suggest that tamoxifen has a different effect on adenohypophysial circulation of the rat depending on whether it is administered in a low- or high-estrogen state.

Cerebral blood flow and the thermal properties of the brain: a preliminary analysis

1989 ◽  
Vol 70 (4) ◽  
pp. 592-598 ◽  
Author(s):  
Michael Salcman ◽  
Eiji Moriyama ◽  
Henry J. Elsner ◽  
Herman Rossman ◽  
Robert A. Gettleman ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Thermal Properties ◽  
Specific Heat ◽  
Correlation Coefficient ◽  
Microwave Antenna ◽  
Microwave Antennas ◽  
Hydrogen Clearance Method ◽  
The Brain ◽  
Hydrogen Clearance

✓ Safe and effective use of hyperthermia for the treatment of brain tumors requires precise control of the distribution of temperatures (that is, the thermal field) within the tumor and within the adjacent brain. Major influences upon the distribution of temperatures include the passive thermal properties of the brain, such as its specific heat (Cb), and the contribution of cerebral blood flow (CBF). Recently, an electrical-mechanical analog model of heat flow within the brain has been developed from which an expression for CBF has been derived: CBF = Cb/(τρc) where τ is the thermal decay constant, ρ is the density of blood, and c is its specific heat. To test this model a series of experiments was carried out in adult dogs in which stereotaxically implanted microwave antennas operating at 2450 MHz, fluoro-optical thermometry probes, and platinum electrodes were used to simultaneously measure CBF by thermal washout and hydrogen clearance techniques. The correlation coefficient for estimates of CBF derived by the two methods in 52 paired observations was 0.89. Measurements of CBF were more reliable at increased distances from the microwave antenna, since CBF is sensitive to the degree of temperature elevation (ΔT). The ratio of post-heating CBF to pre-heating CBF varies linearly with ΔT and has a correlation coefficient of 0.86. When values of CBF determined by the hydrogen clearance method were employed in the above equation, it was possible to derive Cb as 0.70 ± 0.08 cal/gm-°C. Use of this value for Cb in this equation produces estimates of CBF by thermal clearance that are within 10% of the values for CBF as measured by the hydrogen clearance method. It is concluded that this model of thermal flow within the brain may have heuristic value for treatment planning and that microwave antennas and fluoro-optical probes may represent a new methodology for the clinical estimation of CBF. These methods have recently been employed in patients undergoing combined hyperthermia and chemotherapy.

scholarly journals Autoregulation of Cerebral Blood Flow to Changes in Arterial Pressure in Mild Alzheimer's Disease

2010 ◽  
Vol 30 (11) ◽  
pp. 1883-1889 ◽  
Author(s):  
Allyson R Zazulia ◽  
Tom O Videen ◽  
John C Morris ◽  
William J Powers
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Arterial Pressure ◽  
The Elderly ◽  
Local Defect ◽  
Clinical Dementia Rating ◽  
Positron Emission ◽  
Before And After

Studies in transgenic mice overexpressing amyloid precursor protein (APP) demonstrate impaired autoregulation of cerebral blood flow (CBF) to changes in arterial pressure and suggest that cerebrovascular dysfunction may be critically important in the development of pathological Alzheimer's disease (AD). Given the relevance of such a finding for guiding hypertension treatment in the elderly, we assessed autoregulation in individuals with AD. Twenty persons aged 75±6 years with very mild or mild symptomatic AD (Clinical Dementia Rating 0.5 or 1.0) underwent 15O-positron emission tomography (PET) CBF measurements before and after mean arterial pressure (MAP) was lowered from 107±13 to 92±9 mm Hg with intravenous nicardipine; 11C-PIB-PET imaging and magnetic resonance imaging (MRI) were also obtained. There were no significant differences in mean CBF before and after MAP reduction in the bilateral hemispheres (−0.9±5.2 mL per 100 g per minute, P=0.4, 95% confidence interval (CI)=−3.4 to 1.5), cortical borderzones (−1.9±5.0 mL per 100 g per minute, P=0.10, 95% CI=−4.3 to 0.4), regions of T2W-MRI-defined leukoaraiosis (−0.3±4.4 mL per 100 g per minute, P=0.85, 95% CI=−3.3 to 3.9), or regions of peak 11C-PIB uptake (−2.5±7.7 mL per 100 g per minute, P=0.30, 95% CI=−7.7 to 2.7). The absence of significant change in CBF with a 10 to 15 mm Hg reduction in MAP within the normal autoregulatory range demonstrates that there is neither a generalized nor local defect of autoregulation in AD.

The Effects of Paco2 on Regional Cerebral Blood Flow and Internal Carotid Arterial Pressure during Carotid Clamping

1971 ◽  
Vol 35 (3) ◽  
pp. 286-300 ◽  
Author(s):  
Gudru n ◽  
H. J. Ladegaard-Pedersen ◽  
H. Henriksen ◽  
L. Olesen ◽  
O. B. Paulson ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Arterial Pressure ◽  
Regional Cerebral Blood Flow ◽  
Internal Carotid ◽  
Regional Cerebral Blood ◽  
Carotid Arterial

Measurement of local blood flow of the intestine by hydrogen clearance method; Experimental study

1979 ◽  
Vol 9 (1) ◽  
pp. 63-70 ◽  
Author(s):  
Yoshio Mishima ◽  
Hiroshi Shigematsu ◽  
Yoshiaki Horie ◽  
Masanori Satoh
Keyword(s):  
Experimental Study ◽  
Blood Flow ◽  
Local Blood Flow ◽  
Hydrogen Clearance Method ◽  
Hydrogen Clearance

Time-Dependent Changes in Cerebral Blood Flow and Arterial Pressure During Mild +Gz Hypergravity

2018 ◽  
Vol 89 (9) ◽  
pp. 787-791 ◽  
Author(s):  
Toru Konishi ◽  
Takuya Kurazumi ◽  
Tomokazu Kato ◽  
Chiharu Takko ◽  
Yojiro Ogawa ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Arterial Pressure ◽  
Time Dependent
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