• The Korean Journal of Physiology
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• v.20 no.2
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• pp.218-224
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• 1986

The characteristics of anion exchange with internal $HCO_3\;^{-}\;(or\;OH^-)$ was studied by determining the time course of hemolysis in isoosmotic ammonium salt solution in human erythrocytes. The effects of inhibitors, pH and temperature on the exchange between internal $HCO_3\;^-\;(or\;OH^-)$ and external $Cl^-$ were observed and the permeabilities of various organic and inorganic anions were also measured. The results were compared with data previously reported from the experiments using radioisotopes. The results are as follows; 1) SITS $H_2DIDS$ and furosemide inhibited the hemolysis of erythrocytes in isoosmotic $NH_4Cl$ solution in a dose·dependent manner, and the concentrations for lengthening twice the time for $half-hemloysis(t_{1/2})\;were\;2.3{\times}10^{-7},\;1.3{\times}10^{-7}\;and\;2.5{\times}10^{-5}M$, respectively. 2) Acetazolamide also shifted the time-dependent hemolytic curve to the right in a dose-dependent manner, and the concentrations for lengthening twice $t_{1/2}\;was\;2.4{\times}10^{-5}M$. 3) The time-dependent hemolysis was delayed by decreasing pH from 7.0 to 6.2, but w·as not affected by the change of pH in the range of 7.0 to 8.2. 4) The time for $half-hemloysis(t_{1/2})$ showed a temperature-dependency and Arrhenius plot exhibited a break point at $20^{\circ}C$. The apparent activation energy calculated from this plot was 18.1 kcal/mol between $2^{\circ}C-20^{\circ}C$ and 11.2 kcal/mol between $20^{\circ}C-37^{\circ}C$, respectively. 5) The apparent permeabilities of various inorganic anions based on $t_{1/2}$ were in the order of $Cl^->NO_{3}\;^->SCN^->SO_4\;^{2-}>SSO_3\;^{2-}>HPO_4\;^{2-}$. which was similar with the previous reports based on the experiment using radioisotopes. The results Obtained from this study are comparable with the previous data reported from the experiments using radioisotopes. This indicates that the hemolysis of erythrocytes in isoosmotic ammonium salt solution can be used as a simple and good method for the study of anion exchange in erythrocyte membrane.

• The Korean Journal of Nuclear Medicine
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• v.33 no.3
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• pp.247-261
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• 1999

Purpose: The aim of this study was to evaluate the normal values of regional cerebral blood flow (rCBF) and cerebrovascular reserve (CVR) in normal children to aged volunteers using Tc-99m HMPAO, Materials and Methods: Thirty four right-handed normal volunteers (20 males, 14 females, mean age $40.3{\pm}24.9$ years, range 4 to 82 years) were underwent rost/acetazolamide (ACZ) brain SPECT using Tc-99m HMPAO and the sequential injection and subtraction method. rCBF was estimated on the basis of a semiquantitative approach by means of right/left ratio, region/cerebellum and region to whole brain ratios in (rental, parietal, temporal, and occipital lobes, basal ganglia, thalami, and cerebellum. CVR was measured by means of % perfusion increase calculated as % mean count change compared to rest rCBF in each regions. Results: Mean values of right to left ratios range from 1.004 to 1.018, rCBF was highest in cerebellum and lowest in basal ganglia and thalami. Frontal and temporal rCBF decreased while occipital and thalamic rCBF increased according to age. No sexual difference of rCBF was noted. Mean CVR was $29.9{\pm}12.9%$. Mean CVR significantly increased to late teens, and declined thereafter. After 6th decade, CVR in both frontal lobes, left parietal lobe and right basal ganglia decreased significantly with advancing age. There was no sexual difference of CVR. Conclusion: Quantitative assessment of CVR was possible by ACZ Tc-99m HMPAO brain SPECT. It revealed that rCBF and CVR changed according to age in normal Korean volunteers. There was no sexual difference.

• The Korean Journal of Nuclear Medicine Technology
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• v.15 no.1
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• pp.94-100
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• 2011

Purpose: Basal/Acetazolamide-challenged brain perfusion SPECT is very useful to assess cerebral perfusion and vascular reserve. However, as there is a trade off between sensitivity and spatial resolution in the selection of collimator, the selection of optimal collimator is crucial. In this study, we examined three collimators to select optimal one for 1-day brain perfusion SPECT. Materials and Methods: Three collimators, low energy high resolution-parallel beam (LEHR-par), ultra resolution-fan beam (LEUR-fan) and super fine-fan beam (LESFR-fan), were tested for 1-day imaging using Triad XLT 9 (TRIONIX). The SPECT images of Hoffman 3D brain phantom filled with 99mTc of 170 MBq and a normal volunteer were acquired with a protocol of 50 kcts/frame and detector rotation of 3 degree. Filterd backprojection (FBP) reconstruction with Butterworth filter (cut off frequencies, 0.3 to 0.5) was performed. The quantitative and qualitative assessments for three collimators were performed. Results: The blind tests showed that LESFR-fan provided the best image quality for Hoffman brain phantom and the volunteer. However, images for all the collimator were evaluated as 'acceptable'. On the other hand, in order to meet the equivalent signal-to-noise ratio (SNR), total acquisition time or radioactivity dose for LESFR-fan must have been increased up to almost twice of that for LEUR-fan and LEHR-par. The volunteer test indicated that total acquisition time could be reduced approximately by 10 to 14 min in clinical practice using LEUR-fan and LEHR-par without significant loss on image quality, in comparison with LESFR-fan. Conclusion: Although LESFR-fan provides the best image quality, it requires significantly more acquisition time than LEUR-fan and LEHR-par to provide reasonable SNR. Since there is no significant clinical difference between three collimators, LEUR-fan and LEHR-par can be recommended as optimal collimators for 1-day brain perfusion imaging with respect to image quality and SNR.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.2
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• pp.144-152
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• 2016

Carotid-artery stenosis may reduce cerebral perfusion, and affect cerebral neuronal activities. We examined the question of whether the recovery of cerebral-perfusion reserve after carotid-artery stenting (CAS) can affect the EEG power-spectrum. Nineteen candidates for CAS were initially recruited. Subtraction imaging of single photon emissary computerized tomography (SPECT) and an electroencephalogram (EEG) were taken twice, before and 1 month after CAS. At each time point, the EEGs were recorded before and after injection of acetazolamide (pre-ACZ EEG and post-ACZ EEG). Finally, 7 patients were enrolled after exclusion of incomplete studies. We obtained the spectral ratio (SR) of each hemisphere. SR was defined as the divided value of the power-spectrum sum of fast activities by that of slow activities. The power-spectrum values between hemispheres were compared using the inter-hemispheric index of spectral ratio (IHISR), and we examined the correlation between the power-spectrum and the cerebral-perfusion reserve. Cerebral-perfusion reserve improved after CAS on the stent side in 6 of 7 patients. In 3 patients with unilateral carotid-artery stenosis, CAS increased SR on the pre-ACZ EEGs, and IHISR on the post-ACZ EEGs. The increases of SR and IHISR were concordant with the increment of cerebral-perfusion reserve. In contrast, the results in the other patients with bilateral stenosis showed complex patterns. The SR of pre-ACZ EEGs and IHISR of post-ACZ EEGs may be useful electrophysiological markers for the blood-flow reserve after CAS in patients with unilateral carotid-artery stenosis, but not in those with bilateral stenosis.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.4
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• pp.280-286
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• 2009

Purpose: The aim of this study was to evaluate the hemodynamic changes after endovascular stenting in patients with unilateral middle cerebral artery (MCA) stenosis using statistical probabilistic anatomical mapping (SPAM) analysis of basal/acetazolamide (ACZ) Tc-99m ECD brain perfusion SPECT. Materials and Methods: Eight patients (3 men and 5 women, 64.8$\pm$10.5 years) who underwent endovascular stenting for unilateral MCA stenosis were enrolled. Basal/ACZ Tc-99m ECD brain perfusion SPECT studies were performed by one-day protocol before and after stenting. Using SPAM analysis, we compared basal cerebral perfusion (BCP) counts and cerebrovascular reserve (CVR) index of the MCA territory before stenting with those after stenting. Results: After stenting, no patient had any complication nor additional stroke. In SPAM analysis, 7 out of the 8 patients had improved BCP counts of the MCA territory and 7 out of the 8 patients had improved CVR index of the MCA territory after stenting. Before stenting, the mean BCP counts and CVR index in the affected MCA territory were 47.1$\pm$2.2 ml/min/100 g and -2.1$\pm$2.9%, respectively. After stenting, the mean BCP counts and CVR index in the affected MCA territory were improved significantly (48.3$\pm$2.9 ml/min/100 g, p =0.025 and 0.1$\pm$1.3%, p =0.036). Conclusion: This study revealed that SPAM analysis of basal/ACZ brain perfusion SPEG would be helpful to evaluate hemodynamic efficacy of endovascular stenting in unilateral MCA stenosis.

• Journal of Life Science
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• v.24 no.2
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• pp.186-190
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• 2014

Carbonic anhydrase isozymes (CAs) are widespread zinc-containing metalloenzyme family. The enzyme catalyzes the reversible interconversion of $CO_2$ and $HCO_3$. This reaction is the main role of CA enzymes in physiological conditions. CA III, one of the CA isozymes, has been identified in many tissues. It is distinguished from the other isozymes by several characteristics, particularly by a lower specific activity and by its resistance to acetazolamide. However, the physiological function of CA III in fish is unknown. In this study, we examined the detection of CAs in the Shaggy sea raven Hemitripterus villosus, using SDS-PAGE, isoelectric focusing (IEF), and western blot analysis. We detected a significant protein band with molecular weight about 30 kDa from the tissues of H. villosus by SDS-PAGE and western blotting. A specific band of CA III with pI 7.0 was detected by IEF and western blotting in gill and muscle. The immunoreaction of anti-CA III expressed in the gill of H. villosus was much stronger than other tissues. One explanation for this result is that the fish gill is the only organ that is exposed to the external environment and that plays an important role in acid-base relevant ion transfer, the transfer of $H^+$ and/or $HCO{_3}^-$, for the maintenance of systemic pH. This is the first report on the identification of a carbonic anhydrase III-like protein from H. villosus.

• The Korean Journal of Pharmacology
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• v.7 no.1
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• pp.67-76
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• 1971

The excretion of uric acid in man has been of great interest because of its importance as an end product in purine metabolism as well as of its role in causing gout. There are many differences in the modes of renal handling of urate among various species of animals. Uric acid actively secreted by the renal tubules of most vertebrate including amphibians, reptiles, and birds. On the other hand, in most mammals net tubular reabsorption of urate appears to be occurred with some exception, such, as Dalmatian dog. In the rabbits, however, the mechanism of renal excretion of uric acid has long been a subject of controversial results. Within a given group it was possible to find individuals with either net secretion or net reabsorption of urate depend on the experimental conditions. Excretion of urate can be depressed or enhanced by a variety of drugs belonging mainly to the aromatic acid group. Diodrast, probenecid, cinchophen and salicylates have been reported as uricosuric agents, on the other hand, lactate, benzoate, pyrazinoic acid, acetazolamide and chlorothiazide are known to be contraindicated to use for the patient with gout since these agents depress the excretion of uric acid from the kidney. However, complex and sometimes the paradoxical effects on the urate excretion by those above mentioned drugs are not uncommon. The experiments were designed to investigate the mechanisms of renal handling of urate as well as the effects of variety of drugs on the tubular transport of uric acid in the rabbits. Male or female white rabbits, from 1.5 to 2.5 kg in weight, were used. The experimental methods used in these studies were clearance, stop-flow, and retrograde injection techniques. The effects of saline, salicylate, chlorothiazide and probenecid were investigated in each experimental conditions. Results of the experiments were summarized as follows; 1. In the rabbits, the rate of urate clearance was always lower than the rate of inulin clearance. The filtration fraction of the urate was one third on an average, therefore, it is estimated that approximately two thirds of filtered urate was reabsorbed. 2. In the kidneys of rabbits, the urate clearance was increased significantly by administration of chlorothiazide and decreased by probenecid. The administration of salicylate had no effect on the rate of urate clearance. The filtration fraction of urate was increased by chlorothiazide and decreased by probenecid. 3. In the stop-flow studies, the U/P ratio of urate was higher than the U/P ratio of inulin in the proximal region, indicating the secretion of uric acid in the proximal tubules. The proximal peak was increased by chlorothiazide and inhibited by probenecid.4. In the retrograde injection studies, the reabsorption of urate in the proximal region was observed, and these reabsorptive transport of urate was depressed by either probenecid or by chlorothiazide. 5. No distal tubular activity was observed under any of these experimental conditions concerning urate transport. The results of these experiments show that probenecid inhibits both secretory and reabsorptive transport of uric acid in the kidney of the rabbits. The enhancement of secretory transport of urate by chlorothiazide in the clearance study was due to the secondary action of chlorothiazide which inhibits the reabsorptive transport of urate in the proximal tubules. It is evident that the urate transport in the kidneys of rabbits is bidirectional nondiffusive flux both secretory and reabsorptive directions in the proximal tubules.

• The Korean Journal of Nuclear Medicine
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• v.34 no.3
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• pp.183-198
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• 2000

Purpose: The purpose of this study was to evaluate alterations of regional cerebral blood flow (CBF) and cerebrovascular reserve (CVR), and correlation between these alternations and cognitive dysfunction in patients with chronic traumatic brain injury (TBI) and normal brain MRI findings. Materials and Methods: Thirty TBI patients and 19 healthy volunteers underwent rest/acetazolamide brain SPECT using Tc-99m HMPAO. Korean-Wechsler Adult Intelligence scale test was also performed in the patient group. Statistical analysis was performed with statistical parametric mapping software (SPM'97) Results: CBF was diminished in the left hemisphere including Wernicke's area in all patients with lower verbal scale scores. In addition, a reduction in CBF in the right frontal, temporal and parietal cortices was related with depressed scores in information, digital span, arithmetic and similarities. In patients with lower performance scale scores, CBF was mainly diminished in the right hemisphere including superior temporal and supramarginal gyri, premotor, primary somatomotor and a part of prefrontal cortices, left frontal lobe and supramarginal gyrus. CVR was diminished in sixty-four Brodmann's areas compared to control. A reduction in CVR was demonstrated bilaterally in the frontal and temporal lobes in patients with lower scores in both verbal and performance tests, and in addition, both inferior parietal and occipital lobes in information subset. Conclusion: Alterations of CBF and CVR were demonstrated in the symptomatic TBI patients with normal MRI finding. These alterations were correlated with the change of intelligence, of which the complex functions are subserved by multiple interconnected cortical structures.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.4
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• pp.267-274
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• 2008

Purpose: Transient neurological deterioration (TND) is one of the complications after extracranial-intracranial bypass surgery, and it has been assumed to be caused by postoperative transient hyperperfusion. This study was performed to evaluate the relationship between TND and preoperative and postoperative cerebral perfusion status on brain perfusion SPECT following superficial temporal artery - middle cerebral artery (STA-MCA) anastomosis surgery. Materials and Methods: A total of 60 STA-MCA anastomosis surgeries of 56 patients (mean age: $50{\pm}16$ yrs; M:F=29:27; atherosclerotic disease: 33, moyamoya disease: 27) which were done between September 2003 and July 2006 were enrolled. The resting cerebral perfusion and cerebral vascular reserve (CVR) after acetazolamide challenge were measured before and 10 days after surgery using 99mTc-ethylcysteinate dimer (ECD) SPECT. Moreover, the cerebral perfusion was measured on the third postoperative day. With the use of the statistical parametric mapping and probabilistic brain atlas, the counts for the middle cerebral artery (MCA) territory were calculated for each image, and statistical analyses were performed. Results: In 6 of 60 cases (10%), TND occurred after surgery. In all patients, the preoperative cerebral perfusion of affected MCA territory was significantly lower than that of contralateral side (p=0.002). The cerebral perfusion on the third and tenth day after surgery was significantly higher than preoperative cerebral perfusion (p=0.001, p=0.02). In TND patients, basal cerebral perfusion and CVR on preoperative SPECT were significantly lower than those of non-TND patients (p=0.01, p=0.05). Further, the increases in cerebral perfusion on the third day after surgery were significant higher than those in other patients (p=0.008). In patients with TND, the cerebral perfusion ratio of affected side to contralateral side on third postoperative day was significantly higher than that of other patients (p=0.002). However, there was no significant difference of the cerebral perfusion ratio on preoperative and tenth postoperative day between patients with TND and other patients. Conclusion: In patients with TND, relative and moderate hyperperfusion was observed in affected side after bypass surgery. These finding may help to understand the pathophysiology of TND.