Effect of donepezil on brain acetylcholinesterase activity in patients with AD measured by PET

Acetylcholinesterase (AChE) activities in the brain of three patients with AD were measured once before and once during donepezil treatment (5 mg/d in two patients, 3 mg/d in one patient) using PET and N-[11C]methylpiperidin-4-yl acetate. Donepezil reduced k(3) values, an index of AChE activity, in the cerebral cortex by 39 +/- 5%. All patients showed some degree of symptomatic improvement, and it was concluded that this improvement was likely caused by improved cholinergic activity by inhibition of AChE in the brain.

Dose relationship of limbic-cortical D2-dopamine receptor occupancy with risperidone

RATIONALE

It has been suggested that the antipsychotic effect of antipsychotics is mediated by the antagonism of the dopamine D2 receptor in the limbic-cortical regions. Risperidone has an atypical property, but its effect on limbic-cortical regions has not been evaluated.

OBJECTIVES

In this study, we examined the relationship among doses of risperidone and limbic-cortical dopamine D2 receptor occupancy using positron emission tomography.

METHODS

Seven patients with schizophrenia were scanned during the steady state with risperidone. Their occupancies in limbic-cortical regions were determined using positron emission tomography with [11C]FLB 457.

RESULTS

The average occupancy ranged from 38% to 80% on doses of 1-6 mg/day. The saturation curve plotted against the drug level fit the data well.

CONCLUSIONS

Our results demonstrate that the D2 receptor occupancy with risperidone in the limbic-cortical regions seems to be similar to that of previous reports regarding the striatum, and it would be comparable to that of typical antipsychotics.

Trihalomethane removal by activated carbon fiber

For the safety of drinking water, trihalomethanes are removed by adsorption onto activated carbon fiber from single-component solutions. The amounts adsorbed onto adsorbents with large surface area and/or pore volume were small. Stronger surface hydrophobicity of adsorbent was correlated with a larger amount of trihalomethanes adsorbed. A trihalomethane with bromine was adsorbed to a greater extent than that with chlorine. The differences in the amounts adsorbed among trihalomethanes can be explained by the polarity of trihalomethane molecules. The amount of trihalomethanes adsorbed was mainly dominated by the strength of hydrophobicity of activated carbon fibers.

Adenosine-induced coronary flow reserve in Watanabe heritable hyperlipidemic rabbits

The Watanabe heritable hyperlipidemic (WHHL) rabbit develops coronary atherosclerosis and hypercholesterolemia because of a genetic deficiency of low-density lipoprotein receptors and is therefore a good animal model for studying the relationships of coronary atherosclerosis, hypercholesterolemia and coronary flow reserve. The aim of the present study was to assess myocardial perfusion at baseline and during adenosine infusion (0.2 mg x kg(-1) x min(-1)) in 8 WHHL rabbits (13.8+/-0.5 months) with 13N-ammonia, small-animal positron emission tomography (PET) and colored microspheres. Results were compared with those from 6 age-matched Japanese white rabbits. Plaque distribution was also examined in the extramural coronary arteries. All 8 WHHL rabbits had coronary plaques, with 6 showing multiple plaques. Mean global myocardial blood flow (ml x min(-1) x g(-1)) did not differ significantly between control and WHHL groups both at baseline (3.67+/-0.72 vs 4.26+/-1.12 ml x min(-1) x g(-1), p=NS) and with adenosine (7.92+/-2.00 vs 9.27+/-2.91 ml x min(-1) x g(-1), p=NS), nor did coronary flow reserve (2.16+/-0.37 vs 2.18+/-0.41, p=NS). None showed evidence of regional perfusion abnormalities by visual and semiquantitative analyses of PET images. It was concluded that WHHL rabbits preserve adenosine-induced coronary flow reserve despite coronary atherosclerosis and hypercholesterolemia, suggesting that a compensatory mechanism develops in this animal model.

Tumor uptake of radioiodinated anti-human pulmonary surfactant-associated protein monoclonal antibody PE10 in nude mice bearing human pulmonary adenocarcinoma in combination with an unlabeled preload

This study assessed the potential use of radioimmunoscintigraphy of pulmonary alveolar Type II cells tumor with the radiolabeled anti-human surfactant-associated protein (SP) monoclonal antibody (MAb) PE 10 in combination with preloads of unlabeled MAb. The in vitro binding of iodine-125 ((125)I)-labeled MAb PE 10 (1 microg), which had a specific radioactivity of 400 MBq/mg, on human pulmonary papillary adenocarcinoma NCI-H441 cells that produced SP was investigated. In NCI-H441 tumor-bearing nude mice, the tumor uptake of (125)I-MAb PE 10 (5 microg) was examined in combination with preloads of unlabeled MAb PE 10 (0, 5, 10, and 50 microg). An isotype-matched unassociated murine MAb was used as a control both in vitro and in vivo. (125)I-MAb PE 10 showed specific cell binding compared with (125)I-control MAb. Tumor uptake of (125)I-MAb PE 10 in vivo reached a peak of 4.97+/-0.33% injected dose per gram (%ID/g) at 48 h postinjection. Preloads of 5 and 10 microg unlabeled MAb PE 10 significantly enhanced tumor uptake at 48 h postinjection ( 5.94+/-0.29% ID/g and 5.72+/-0.29% ID/g, respectively), whereas preload of 50 microg unlabeled MAb PE 10 significantly decreased tumor uptake ( 2.75+/-0.32% ID/g) at 48 h. Preload of 5 microg unlabeled MAb PE 10 significantly increased the tumor-to-blood radioactivity ratio at 48 h ( 2.39+/-0.16). Preloads of unlabeled control MAb did not cause any significant change in tumor uptake. Immunohistochemistry showed the intracellular and pericellular patterns of SP expression in tumor cells. In conclusion, radioimmunoscintigraphy with MAb PE 10 labeled with a gamma-emitting radioiodine such as (123)I might be a useful means of targeting pulmonary alveolar Type II tumor cells in combination with preloading with an optimal dose of the unlabeled MAb.

Brain acetylcholinesterase activity in Alzheimer disease measured by positron emission tomography

Brain acetylcholinesterase activity was measured in 14 patients with Alzheimer disease and 14 age-matched control subjects by positron emission tomography with a radioactive acetylcholine analogue. Kinetic analysis was performed to calculate k3, an index of acetylcholinesterase activity. The k3 values were significantly reduced in the neocortex, hippocampus, and amygdala of all patients with Alzheimer disease, suggesting a loss of cholinergic innervation from the basal forebrain. Most profound reductions of k3 values were observed in the temporal (-30%) and parietal cortices (-31%), although reductions of k3 values were relatively uniform in the cerebral neocortex. This technique may be a powerful tool for early diagnosis of Alzheimer disease and also for therapeutic monitoring of acetylcholinesterase inhibitors in Alzheimer disease.

Characteristics of Nonafluorobutyl Methyl Ether (NFE) Adsorption onto Activated Carbon Fibers and Different-Size-Activated Carbon Particles

The characteristics of adsorption of 1,1,1,2,2,3,3,4,4-nonafluorobutyl methyl ether (NFE), a chlorofluorocarbon (CFC) replacement, onto six different activated carbon; preparations (three activated carbon fibers and three different-sized activated carbon particles) were investigated to evaluate the interaction between activated carbon surfaces and NFE. The amount of NFE adsorbed onto the three activated carbon fibers increased with increasing specific surface area and pore volume. The amount of NFE adsorbed onto the three different-sized-activated carbon particles increased with an increase in the particle diameter of the granular activated carbon. The differential heat of the NFE adsorption onto three activated carbon fibers depended on the porosity structure of the activated carbon fibers. The adsorption rate of NFE was also investigated in order to evaluate the efficiency of NFE recovery by the activated carbon surface. The Sameshima equation was used to obtain the isotherms of NFE adsorption onto the activated carbon fibers and different-sized-activated carbon particles. The rate constant k for NFE adsorption onto activated carbon fibers was larger for increased specific surface area and pore volume. The rate of NFE adsorption on activated carbons of three different particle sizes decreased with increasing particle diameter at a low initial pressure. The adsorption isotherms of NFE for the six activated carbons conformed to the Dubinin-Radushkevich equation; the constants BE(0) (the affinity between adsorbate and adsorbent) and W(0) (the adsorption capacity) were calculated. These results indicated that the interaction between the activated carbon and NFE was larger with the smaller specific surface area of the activated carbon fibers and with the smaller particle diameter of the different-sized-activated carbon particles. The degree of packing of NFE in the pores of the activated carbon fibers was greater than that in the pores of the granular activated carbons. Copyright 2000 Academic Press.

Progressive loss of cortical acetylcholinesterase activity in association with cognitive decline in Alzheimer's disease: a positron emission tomography study

We measured brain acetylcholinesterase activity in 30 patients with Alzheimer's disease (AD) and 14 age-matched controls by positron emission tomography (PET) and using a carbon 11-labeled acetylcholine analogue. Seven AD patients had repeat PET scans. The k3 values were calculated as an index of acetylcholinesterase activity in a three-compartment analysis using the metabolite corrected arterial input function. Twenty-eight of the 30 AD patients (14 each in the early and late onset subgroups) were retained in the study so as to equalize the range and average severity of cognitive impairment within the early and late onset subgroups. The k3 values were significantly reduced in the neocortex, hippocampus, and amygdala in the early onset AD patients, although the k3 values were significantly reduced only in the temporoparietal cortex and amygdala in the late onset AD patients. In the longitudinal study, all 7 repeat AD patients showed further reduction of cortical k3 values in the second PET scans, with a mean interval of 2 years, suggesting a progressive loss of the ascending cholinergic system from the nucleus basalis of Meynert in AD. In 37 AD patients, there was a highly significant correlation between the cortical k3 values and Mini-Mental State Examination scores, supporting the cholinergic hypothesis in AD.

[A cross-sectional study on the relationship of plasma fibrinogen concentration and age, physical fitness, lifestyle and health examinations of healthy Japanese males]

The intention of this study was to examine the determinants of plasma fibrinogen concentrations in healthy Japanese male workers. A cross-sectional study was conducted in 1998 among 1,044 (male 975, female 69) employees aged 30-59 years in Osaka, Japan. The overall mean value of plasma fibrinogen concentration was 236.4 +/- 47.6 mg/dl. There was a dose-response relationship between cigarette smoking and plasma fibrinogen concentration. Plasma fibrinogen concentration was associated with age, body weight, body mass index, white blood cell count and CPITN score, and inversely associated with serum HDL cholesterol in male nonsmokers. Plasma fibrinogen was not related to physical exercise, alcohol consumption or dietary factors. This study confirms the relationship of known coronary risk factors to plasma fibrinogen concentration in Japanese male factory workers, and suggests that smoking and periodontal disease are related to plasma fibrinogen concentrations.

Activity of platelet-activating-factor-acetylhydrolase and the nitric oxide metabolite level in the plasma of pregnant women who develop transient hypertension during later pregnancy

It is reported that plasma platelet-activating-factor-acetylhydrolase (PAF-AH) is elevated in patients with essential hypertension. In this study, plasma PAF-AH activity was measured during pregnancy and after delivery to examine the relationship between plasma PAF-AH activity and the development of transient hypertension (TH) during pregnancy. Moreover, in order to examine the involvement of endothelial injury in TH, the plasma level of nitric oxide metabolite (NOx; NO2+NO3) was measured. The plasma PAF-AH activity in 51 pregnant women was consecutively measured in the 1st, 2nd and 3rd trimesters of gestation, and after delivery. Forty-one cases were normal pregnancies and 10 cases were complicated by TH later during pregnancy. The PAF-AH activity in the normal pregnancy group decreased in the 2nd trimester of gestation compared with the 1st trimester, but was elevated in the TH group. The incidence of elevation of PAF-AH in the TH group was significantly (7/10; 70.0%; P<0.01, Chi-squared test) higher than in the normal pregnancy group (9/41; 22.0%). The plasma NOx levels in the 2nd trimester were higher than those in the 1st trimester in both the normotensive and TH group (P<0.05 for both comparisons). The 51 patients were classified into two groups according to the change in the PAF-AH in the 2nd trimester: group A consisted of 35 patients whose PAF-AH activity did not increase, and group B consisted of 16 patients whose PAF-AH activity increased. The incidence of development of TH during later pregnancy in group B was significantly (7/16; 43.8%; P<0.01, Chi-squared test) higher than in group A (3/35; 8.6%). Hypertension developed after 36 weeks' gestation in all patients in the TH group. The results of the present study suggest that changes in PAF metabolism may relate to regulation of blood pressure in pregnant women whose pregnancy is complicated with TH, whereas NO metabolism does not differ between women with TH and those having a normal pregnancy.

Seizure frequency and bilateral temporal abnormalities: a proton magnetic resonance spectroscopy of temporal lobe epilepsy

Proton magnetic resonance spectroscopy ((1)H-MRS) was performed in seven healthy volunteers and 17 patients with temporal lobe epilepsy (TLE) to clarify the correlation of the severity of epilepsy with bilateral temporal changes in N-acetylaspartate (NAA), choline-containing compounds (Cho) and creatine + phosphocreatine (Cr). Despite unilateral EEG focus, bilateral temporal reduction in NAA /(Cho + Cr) was revealed in patients with intractable seizures. The potential for seizure generation correlated with the NAA /(Cho + Cr) reduction not only on the ipsilateral side but also on the contralateral side. Proton MRS proved to be a useful measurement for obtaining important information about the neuronal changes as well as the lateralization of the epileptogenic focus in TLE patients.

Reduction of Iron(III) Ion by Activated Carbon Fiber

The mechanisms of adsorption of iron(II) ion, iron(III) ion, and reduced iron(III) ion onto an activated carbon fiber and the ability of carbon fibers to reduce iron(III) ion were investigated on the basis of the amounts of iron ion adsorbed. The amount of iron(II) ion adsorbed onto the activated carbon fiber increased with increasing adsorption temperature. Iron(II) ion was more easily removed by the activated carbon fiber than iron(III) ion. Iron(III) ion was adsorbed onto the activated carbon fiber after being reduced to iron(II) ion. The reduction ability of A-20 was stronger than that of A-10 because the hydrophilic groups of A-20 were larger than those of A-10. It is concluded that the activated carbon fiber has a reduction effect on iron(III) ion and that the reduction effect of the activated carbon fiber depended on the number of hydrophilic groups on the activated carbon fiber. Copyright 2000 Academic Press.

Uptakes and images of 38K in rabbit heart, kidney, and brain

The purpose of this study was to evaluate the kinetics and image quality of positron-emitting 38K (half-life, 7.6 min) and high-resolution small-animal PET in the heart, kidney, and brain of rabbits.

METHODS

Studies were performed with 18 closed-chest anesthetized rabbits at baseline and during infusions of adenosine (0.2 mg/kg/min) and propranolol (0.5-1.0 mg/kg intravenously) using high-resolution small-animal PET. 38K was injected intravenously and dynamic PET imaging of the heart, kidney, or brain was performed for 3 min. Colored microspheres were injected into the left ventricle to measure organ blood flow. Arterial blood was withdrawn directly from the femoral artery, and, after the animals were killed, 38K activities in each organ were measured directly with a well counter. Uptake of 38K was calculated by dividing the 38K activities in each organ by the integral of the input function. The extraction fraction of 38K was estimated by dividing the uptake of 38K in each organ by the organ blood flow, measured by microspheres.

RESULTS

The left ventricular myocardium and kidney were clearly visualized, but there was no visual 38K uptake in the brain. For the heart, kidney, and brain, respectively, average blood flow was 2.91 +/- 1.29, 5.49 +/- 0.71, and 0.57 +/- 0.11 mL/min/g, and the extraction fraction of 38K at baseline was 0.55 +/- 0.13, 0.48 +/- 0.13, and 0.022 +/- 0004. The Renkin-Crone model fit the relation between myocardial extraction and flow under a wide range of myocardial blood flow (r = 0.89).

CONCLUSION

38K is a suitable tracer for noninvasively showing the potassium kinetics of the heart, kidney, and brain by PET imaging.

CaNa2EDTA for improvement of radioimmunodetection and radioimmunotherapy with 111In and 90Y-DTPA-anti-CEA MAbs in nude mice bearing human colorectal cancer

111In and 90Y, dissociated from 111In-labeled-monoclonal antibody (MAb) and 90Y-labeled MAb, may cause deterioration of the image quality in radioimmunodetection (RID) and undesirable irradiation of nontargeted tissue in radioimmunotherapy (RIT), respectively. The aim of this study was to investigate any improvement in RID and RIT with 111In-MAb and 90Y-MAb by pre- and postadministration of calcium disodium ethylenetriaminetetraacetic acid (CaNa2EDTA).

METHODS

Murine MAb F33-104 against carcinoembryonic antigen (CEA) was labeled with 111In or 90Y by the diethylenetriamine pentaacetic (DTPA)-anhydride method. The influence of CaNa2EDTA on loss of radioactivity from 111In-MAb or 90Y-MAb in serum was investigated in vitro. The effects of CaNa2EDTA, administered before and after 111In-MAb or 90Y-MAb, on the biodistribution of radioactive isotopes in nude mice bearing human colon adenocarcinoma LS 180 tumor expressing CEA, or human pulmonary carcinoma PC 9 tumor expressing no CEA, were then examined. As a control, 0.9% NaCl was used in both the in vitro and in vivo studies.

RESULTS

CaNa2EDTA did not cause any decrease in levels of radioactivity of radiolabeled MAbs. Pre- and post-treatment with CaNa2EDTA reduced radioctivity in both specific and nonspecific tumors at 72 h after 111In-MAb injection resulting in an increase of the specific tumor-to-nonspecific tumor radioactivity ratio. The levels of hepatic and renal radioactivity were also subsequently decreased by CaNa2EDTA. On the other hand, CaNa2EDTA pre- and post-treatment reduced levels of bony, hepatic, and renal radioactivity at 24, 72, and 72 h, respectively, after 90Y-MAb injection, although it had no effect on tumor radioactivity.

CONCLUSION

Pre- and post-treatment with CaNa2EDTA would be of great use in humans who undergo RID or RIT with 111In-MAb and 90Y-MAb accompanied by disassociation of the labeled radionuclides.

Competitive Adsorption of Chloroform and Iron Ion onto Activated Carbon Fiber

Chloroform in tap water has been a significant problem because it may be a carcinogenic substituent. Iron ion exists in tap water because of dissolution from iron water pipes. Iron ions in tap water cause discoloration and a bad odor. The isotherms of chloroform and iron ion adsorption onto activated carbon fibers in a single solution (chloroform or iron ion) and in a binary mixture solution (chloroform and iron ion) were investigated to estimate the competitiveness between chloroform and iron ions. The amount of adsorbed iron ions increased with increasing pore volume of the activated carbon fibers, while that of chloroform decreased. The amount of chloroform adsorbed onto the activated carbon fibers in the binary mixture solution was greater than that in the single solution. These results indicate that the adsorption of chloroform and iron ion onto activated carbon fibers could be competitive. Copyright 1999 Academic Press.

Effect of edetate calcium disodium on yttrium-90 activity in bone of mice

The kinetics of Yttrium-90 (Y-90) in bone of mice was investigated in combination with edetate calcium disodium (CaNa2EDTA). One group of mice were intraperitoneally administered 37.5 mg/kg CaNa2EDTA or 0.9% NaCl as a control at 1, 22, 34, 46, 58, 70, 82, 94, 154 and 166 h after injection of Y-90 acetate (post-administration), and the biodistribution was studied at 3, 24, 72, 120 and 168 h postinjection of Y-90 acetate. No difference between the post-CaNa2EDTA-treated mice and the control was demonstrated in the radioactivity in the bone. A decrease in radioactivity in the liver and kidneys was accelerated, and the radioactivity was lower than the control at 120 h postinjection. The other group of mice were also given the same dose of chelator at 12 h and 1 h preinjection of Y-90 acetate and at 1, 22, 34, 46, 58, 70, 82, 94, 154 and 166 h after injection of Y-90 acetate (pre- and post-administration), the radioactivity in bone at 3 h postinjection was significantly lower than in the control (24.4 +/- 3.92% ID/g vs. 31.7 +/- 2.26% ID/g, p < 0.05), but the decrease was not sequential. A significant reduction in radioactivity in the blood, kidneys and liver was demonstrated at 3 h, 72 h and 72 h postinjection. In conclusion, the CaNa2EDTA with the administration schedule employed here cannot chelate the Y-90 from bone but the free Y-90 before deposition into bone.

Localization of indium-111 in human malignant tumor xenografts and control by chelators

The kinetics of soluble indium-111 ((111)In) in human malignant tumor xenografts and cells was investigated in combination with chelators. Firstly, without chelator, the kinetics of (111)In-chloride was investigated in vitro and in vivo using four human malignant neuroblastoma SK-N-MC, pulmonary papillary adenocarcinoma NCI-H441, pulmonary squamous cell carcinoma PC 9, and colon adenocarcinoma LS 180 cells and xenografts. (111)In was incorporated into tumor cells in vitro to a maximum level during a 60-min incubation. A maximum level of radioactivity was demonstrated in vivo in four human malignant tumors xenografted into nude mice at 24 h postinjection of (111)In-chloride. Secondly, the effect of edetate calcium disodium (CaNa2EDTA) on radioactivity in (111)In-labeled tumors xenografts and cells was studied in vitro and in vivo. CaNa2EDTA significantly reduced (111)In-activity from the labeled tumor xenografts, whereas it had no affect on the radioactivity in the labeled cells. Thirdly, the effect of CaNa2EDTA on radioactivity in human malignant tumors xenografted into nude mice injected with (111)In-chloride was investigated. In one group of mice CaNa2EDTA administered intraperitoneally at 1, 22, 34, 46, 58, and 70 h after injection of (111)In-chloride (postadministration), the localization of (111)In at the tumors was significantly decreased at 72 h compared with the control in all four tumor types. In the other group of mice, CaNa2EDTA administered intraperitoneally at 12 and 1 h before injection of (111)In-chloride and 1, 22, 34, 46, 58, and 70 h postinjection (pre- and postadministration), the radioactivity of tumors was also significantly decreased at 72 h, and the reduction was greater than that with use of postadministration. In a comparative study, CaNa3DTPA had a more powerful effect than CaNa2EDTA. In conclusion, (111)In-activity in tumors consists of intracellular and extracellular components, and the extracellular (111)In may be cleared by chelators. Pre- and postadministration of CaNa3DTPA could remove (111)In-nonspecific localization in tumors when (111)In is released from the radiolabeled agents.

Yttrium-90-labeled human macroaggregated albumin for internal radiotherapy: combined use with DTPA

The aim of this study was to investigate the possibility of yttrium-90-labeled human macroaggregated albumin (90Y-MAA) as an internal radiotherapeutic agent for whole-lung irradiation in combination with diethylenetriamine pentaacetic acid (DTPA). The influence of trisodium calcium DTPA (CaNa3DTPA) on the radioactivity of 90Y-MAA in serum was investigated in vitro. The effect of CaNa3DTPA on the biodistribution of radioactivity in normal mice intraveneously injected with 90Y-MAA was examined. CaNa3DTPA could deprive in vitro radioactivity of 90Y-MAA in 48-h incubation. Most of the radioactivity (>90% injected dose per lung) was observed at murine lung after injection of 90Y-MAA. Pulmonary radioactivity was cleared within 72 h postinjection, whereas the radioactivities in the bone, liver, kidneys, and spleen increased with a peak at 48 h. CaNa3DTPA-treatment reduced the in vivo radioactivities in bone, liver, and kidneys without influence on the radioactivity of lung. In conclusion, combined use of CaNa3DTPA enables 90Y-MAA to be used as a radiopharmaceutical for internal irradiation against whole lung.

Removal of Aromatic Hydrocarbon Compounds by Hydroxypropyl-cyclodextrin

Activated carbon has been used for the recovery and removal of benzene, toluene, and xylenes in air and water for a long time. However, removal of benzene, toluene, and xylenes from soil is very difficult. They can be removed by an increase in the apparent solubility of organic compounds in soil. The apparent solubilities of benzene, toluene, and xylene were investigated to estimate their inclusion behavior into natural cyclodextrins (CDs) and hydroxypropyl-cyclodextrins (HP-CDs) in the liquid phase. The apparent solubilities of benzene, toluene, and xylenes did not increase by adding natural CDs but did increase when HP-CDs were added. Benzene, toluene, and xylenes in a HP-CD solution depended on the relationship between the molecular diameter of benzene, toluene, and xylenes, the CD cavity size, and the 1-octanol-water partition coefficient. That of p-xylene was larger than that of o-xylene and m-xylene because of the smallest steric hindrance of p-xylene. Copyright 1999 Academic Press.

In vitro and in vivo comparison of binding of 99m-Tc-labeled anti-CEA MAb F33-104 with 99m-Tc-labeled anti-CEA MAb BW431/26

AIM

The purpose of this study was to assess the potential for radio-immunodetection (RAID) of murine anti-carcinoembryonic antigen (CEA) monoclonal antibody (MAb) F33-104 labeled with technetium-99m (99m-Tc) by a reduction-mediated labeling method.

METHODS

The binding capacity of 99m-Tc-labeled anti-CEA MAb F33-104 with CEA by means of in vitro procedures such as immunoradiometric assay and cell binding assay and the biodistribution of 99m-Tc-labeled anti-CEA MAb F33-104 in normal nude mice and nude mice bearing human colon adenocarcinoma LS180 tumor were investigated and compared with 99m-Tc-labeled anti-CEA MAb BW431/26.

RESULTS

The in vitro binding rate of 99m-Tc-labeled anti-CEA MAb F33-104 with CEA in solution and attached to the cell membrane was significantly higher than 99m-Tc-labeled anti-CEA MAb BW431/261 (31.4 +/- 0.95% vs. 11.9 +/- 0.55% at 100 ng/mL of soluble CEA, 83.5 +/- 2.84% vs. 54.0 +/- 2.54% at 10(7) of LS 180 cells). In vivo, accumulation of 99m-Tc-labeled anti-CEA MAb F33-104 was higher at 18 h postinjection than 99m-Tc-labeled anti-CEA MAb BW431/26 (20.1 +/- 3.50% ID/g vs. 14.4 +/- 3.30% ID/g). 99m-Tc-activity in the kidneys of nude mice bearing tumor was higher at 18 h postinjection than at 3 h (12.8 +/- 2.10% ID/g vs. 8.01 +/- 2.40% ID/g of 99m-Tc-labeled anti-CEA MAb F33-104, 10.7 +/- 1.70% ID/g vs. 8.10 +/- 1.75% ID/g of 99m-Tc-labeled anti-CEA MAb BW431/26).

CONCLUSION

99m-Tc-labeled anti-CEA MAb F33-104 is a potential novel agent for RAID of recurrent colorectal cancer.

A case of clitoral metastasis without skin involvement from rectal cancer

An 84-year-old woman visited a private dermatologist and gynecologist due to pain in the external genitals. However, no abnormality was found. She was referred to a surgeon in our hospital to clarify the etiology of the pain. Rectal cancer and liver metastatic tumor were detected, and the rectal cancer was resected. However, the pain increased after the operation and she was referred to our department. No macroscopic abnormalities of the external genitals were found. However, a vaginal examination could not be performed due to severe pain. By local examination under anesthesia, enlargement of the clitoris was detected. A simple clitoridectomy was performed. Histological examination revealed that the clitoral tumor was metastatic cancer originating from rectal cancer.

Positron emission tomographic measurement of acetylcholinesterase activity reveals differential loss of ascending cholinergic systems in Parkinson's disease and progressive supranuclear palsy

We measured brain acetylcholinesterase activity in 16 patients with Parkinson's disease (PD), 12 patients with progressive supranuclear palsy (PSP), and 13 age-matched controls, using N-methyl-4-[11C]piperidyl acetate and positron emission tomography. Kinetic analysis was performed to calculate k3, an index of acetylcholinesterase activity. In PD patients, there was a significant reduction (-17%) of cerebral cortical k3 compared with normal controls, whereas there was only a nonsignificant reduction (-10%) of cortical k3 in PSP patients. However, there was a prominent reduction (-38%) of thalamic k3 in PSP patients compared with normal controls, whereas there was only a nonsignificant reduction (-13%) of thalamic k3 in PD patients. The results suggest that there is a loss of cholinergic innervation to the cerebral cortex in association with cholinergic innervation to the thalamus in PD, whereas there is a preferential loss of cholinergic innervation to the thalamus in PSP. When the thalamic to cerebral cortical k3 ratio was taken for each subject, PD and PSP were separated, suggesting that positron emission tomography measurement of acetylcholinesterase activity may be useful for differentiating the two similar disorders.

A preliminary study for clinical pharmacokinetics of oral fluorine anticancer medicines using the commercial MRI system 19F-MRS

These preliminary studies of dynamic natural abundance 19F-magnetic resonance spectroscopy (19F-MRS) on 5-FU based medicines were performed in the human liver using commercial 1.5 T MRI equipment. A single tuned, custom-made circular shape surface coil with a diameter of 15 cm operating at 60 MHz was used for the 19F-MRS study. Localized proton shimming with a whole body coil was performed with adequate volume to include the observing area of the surface coil, and the line width of the water signal was less than 40 Hz. Very different spectroscopic appearance patterns of 5-FU were observed. We examined whether the pharmacokinetics in the liver of orally administered 1-hexylcarbamoyl-5-fluorouracil (HCFU) differ from those of orally administered 5'-deoxy-5-fluorouridine (5'-DFUR). This preliminary study suggested the 19F-MRS technique could be a useful method of evaluating in vivo the metabolism of 5-FU based medicines.