Subacute Progressive Hearing Loss and Lower Body Parkinsonism in Primary Sjögren's Syndrome.

In primary Sjögren's syndrome, it is extremely rare to observe subacute progressive lower-body parkinsonism with severe sensory hearing loss responsive to corticosteroid therapy. Sjögren's syndrome can cause heterogeneous symptoms; therefore, its diagnosis and introduction of treatment are prone to be delayed, particularly in cases without sicca symptoms or seronegative cases, which are more likely to be seen in patients with neurological complications. This report may help clinicians identify atypical early neurological symptoms in primary Sjögren's syndrome.

Utility of a Systematic Approach to Selecting Candidate Prodrugs: A Case Study Using Candesartan Ester Analogues.

Development of prodrugs is a useful strategy to overcome some disadvantages of candidate drugs. Recently, we established a systematic approach to selecting appropriate prodrugs, and validated the utility of this approach using oseltamivir analogues. In this study, the utility of the approach was further examined using candesartan cilexetil and 20 kinds of its analogues having various types of side chain as model compounds. Log D values of analogues (2.5 to 4.7) were higher than that of candesartan (1.0), their active metabolite, and the results were reasonable for the purpose of improving permeability of candesartan. The analogues tended to be more soluble in artificial intestinal fluids than in artificial gastric fluid, owing to their acidic physicochemical characteristics. Their membrane permeabilities were not correlated with log D values, which can be attributed to the metabolism in Caco-2 cells used in this system. In human hepatocytes and enterocytes, 11 out of the 20 analogues were immediately hydrolyzed to candesartan, and species differences were observed in the hydrolysis efficiency. This study confirmed the utility of the systematic approach for selection of appropriate prodrugs that could be proceeded to in vivo pharmacokinetics study, with selection of suitable experimental animals.

Analysis of LIN28A variants in patients with Parkinson's disease.

A heterozygous loss-of-function variant in lin-28 homolog A (LIN28A) was recently reported as a novel pathogenic gene in patients with PD from Korea. Two patients harboring LIN28A variants had early- or middle-aged-onset PD with good responses to levodopa. In the current study, we aimed to identify the prevalence of LIN28A variants among PD patients of Japanese origin. We performed genetic sequencing of 284 patients with early-onset PD. We then estimated the frequency and functional effect of each variant using prediction tools. We identified three different rare variants in LIN28A (rs4623750, c.228 + 49 C > T; rs199541048, c.*7 A > G; and rs4659441, c.*43 C > T). The frequency of each variant in the PD patients did not differ from that of the general population. No variants were identified in the amino acid-coding regions. Our results do not support a strong association of LIN28A with early-onset PD among Japanese patients.

Reversible Pisa syndrome caused by chronic subdural hematoma in a patient with Parkinson's disease: a case report.

BACKGROUND: Pisa syndrome (PS), characterized by lateral trunk flexion, is quite common in patients with Parkinson's disease (PD). Patients with PS are older and have a significantly longer disease duration, more severe motor phenotype, ongoing combined treatment with levodopa and dopamine agonists, and higher levodopa equivalent daily dose. We describe here, to the best of our knowledge, the first case of a woman with PD who developed acute-onset PS caused by chronic subdural hematoma (CSDH). CASE PRESENTATION: A 70-year-old woman developed acute-onset lateral flexion of her trunk to the left side while standing, and she was admitted to our hospital. One month before, she had a mild head trauma with loss of consciousness. At 65 years of age, she noticed difficulty with walking and clumsiness with her hands. She was diagnosed as having PD (Hoehn and Yahr stage 2) and levodopa was initiated. Her symptoms were markedly improved. At 67 years of age, she developed orthostatic hypotension and was treated sequentially with fluids, compression stockings, and midodrine. Urgently performed brain computed tomography (CT) showed a CSDH in the right hemisphere resulting in a marked compression of the hemisphere. After surgical evacuation, her PS disappeared. She has fully recovered to her preoperative level of function. CONCLUSION: The present case provides a valuable insight, that is, the mesial frontal lobe and its connections from the posterior parietal cortex play crucial roles in maintaining the body schema and in the pathophysiology of PS. This case suggests that CSDH should be considered when clinicians examine acute-onset PS, even in patients with neurodegenerative disorders such as PD. Appropriate patient triage and timely neurosurgical intervention should be considered.

An 88-year-old woman with acute disseminated encephalomyelitis following messenger ribonucleic acid-based COVID-19 vaccination.

A global pandemic has resulted from the emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19). To control the spread of SARS-CoV-2 infection, several SARS-CoV-2 vaccines have been developed and administered in a wide range of age groups. Messenger ribonucleic acid (mRNA)-based COVID-19 vaccines are the most widely used. We present the case of an 88-year-old woman who was diagnosed with acute disseminated encephalomyelitis (ADEM) following her second mRNA COVID-19 vaccination. She was admitted to hospital with disturbed consciousness (Glasgow Coma Scale E1V1M4) and gaze-evoked nystagmus. Brain magnetic resonance imaging revealed bilateral presence of middle cerebellar peduncle sign. Following steroid pulse therapy, clinical symptoms improved. The occurrence of ADEM following COVID-19 vaccination does not question the importance of vaccination programs during the COVID-19 pandemic. COVID-19 vaccines have been administered to individuals of a wide range of ages, from children to older adults. Thus, ADEM could occur following COVID-19 vaccination at any age, although ADEM is rare in older adults.

Systematic Approach for Screening of Prodrugs: Evaluation Using Oseltamivir Analogues as Models.

Prodrug development is a common approach in drug development. In a recent study, we established a systematic strategy for selecting prodrugs with improved membrane permeability or solubility based on log D value, solubility in artificial intestinal fluids, membrane permeability, and metabolic instability. The purpose of this study was to evaluate the utility of this strategy using oseltamivir and 23 kinds of oseltamivir analogues having various types of side chain as well as their active metabolite, oseltamivir acid. Log D values of oseltamivir and analogues (2.0 to 4.9) were higher than that of oseltamivir acid (0.7), supporting the previous development of oseltamivir to improve permeability of oseltamivir acid. Solubilities of analogues in artificial intestinal fluids were over 80%, except the compound with the highest lipophilicity. Positive correlation was observed between membrane permeability and log D values of analogues. In metabolic profiles, species differences in the hydrolysis efficiency were observed depending on analogues. Using our strategy, it was demonstrated that oseltamivir and some analogues are appropriate prodrugs that could be advanced to in vivo pharmacokinetic studies, with selection of suitable animals. This study confirmed the utility of our strategy for narrowing down of candidate compounds to proceed into in vivo study.

A Novel Systematic Approach for Selection of Prodrugs Designed to Improve Oral Absorption.

To increase the success rate in development of prodrugs, we sought to establish a systematic in vitro method to appropriately select candidate prodrugs. Physicochemical/biopharmaceutical properties of 21 commercially available prodrugs (16 with improved membrane permeability of pharmacologically active metabolites and 5 with improved solubility) and their active metabolites were characterized in terms of solubility in artificial intestinal fluids and membrane permeability using Caco-2 cells. Their in vitro metabolic profiles were also evaluated, using human and animal enterocytes, hepatocytes, and sera. Log D values of prodrugs with improved membrane permeability were higher than those of their active metabolites, whereas those of prodrugs with improved aqueous solubility were lower than those of active metabolites. The prodrugs with improved aqueous solubility were highly soluble in artificial intestinal fluids. All prodrugs were efficiently converted to active metabolites with human matrices, whereas some were not with dog or monkey matrices. This study demonstrated that physicochemical/biopharmaceutical properties could be useful information to facilitate design of prodrugs and for selection of candidate prodrugs. Moreover, the in vitro evaluation of conversion efficiency to active metabolites would be helpful for selecting ideal prodrugs as well as appropriate animals for in vivo PK studies.

Environmental fate of pharmaceutical compounds and antimicrobial-resistant bacteria in hospital effluents, and contributions to pollutant loads in the surface waters in Japan.

Environmental fate of 58 pharmaceutical compounds (PhCs) grouped into 11 therapeutic classes in the three different waters, hospital effluent, sewage treatment plant (STP) and river water, was estimated by combination of their quantitative concentration analysis and evaluation of their extent of contribution as loading sources. At the same time, distribution of six classes of antimicrobial-resistant bacteria (AMRB) in the same water samples was estimated by screening of individual PhC-resistant microbes grown on each specific chromogenic medium. The results indicate that 48 PhCs were detected ranged from 1 ng/L (losartan carboxylic acid) to 228 µg/L (acetaminophen sulfate) in hospital effluent, and contribution of the pollution load derived from hospital effluent to STP influent was estimated as 0.1% to 15%. On the other hand, contribution of STP effluent to river water was high, 32% to 60% for antibacterials, antipertensives and X-ray contrast media. In the cases for AMRB, detected numbers of colonies of AMRB in hospital effluent ranged from 29 CFU/mL to 1805 CFU/mL, and the estimated contribution of the AMRB pollution load derived from hospital effluent to STP influent was as low as 0.1% (levofloxacin and olmesartan) to 5.1% (N-desmethyl tamoxifen). Although the contribution of STPs as loading sources of PhCs and AMRB in surface waters was large, ozonation as an advanced water treatment system effectively removed a wide range of both PhCs and AMRB in water samples. These results suggest the importance of reducing environmental pollutant loads (not only at STPs but also at medical facilities) before being discharged into the surface waters, to both conserve water and keep the water environment safe. To our knowledge, this is the first report to show the distribution and contribution of AMRB from hospital effluent to the surface waters.

The Validation of the Dai Nippon Medi·Ca SA Method for AOAC Research Institute Performance Tested MethodsSM Certification.

A ready-made dry medium method for Staphylococcus aureus count, the Medi·Ca SA method incubated at 35 or 37°C, was compared with the Baird-Parker method (AOAC Official MethodSM 975.55) for 11 food matrices: raw beef, raw ground beef, raw lamb, cooked ham, raw salmon, frozen prawn, fresh chilled pasta, pasteurized milk, natural cheese, cream puff, and potato salad. The mean difference between the two methods at each contamination level for each matrix was <0.5 log10, and the 95% confidence intervals on the mean differences fell within the range of -0.50 to 0.50. Standard deviation of repeatability and RSDr values of the Medi·Ca SA method were generally the same level as those of the Baird-Parker method, and r2 ranged from 0.98 to 1.00. Product consistency and stability studies showed little variability between productions lots and a shelf-life of 16 months. Incubation time within the range of 22-26 h and variations to the sample volume did not adversely affect the results. These results showed that the Medi·Ca SA method is a reasonable alternative to the reference method for selected food matrices and makes it possible to simultaneously detect and enumerate S. aureus in only 24 h.

Performance and efficiency of removal of pharmaceutical compounds from hospital wastewater by lab-scale biological treatment system.

The fate of pharmaceuticals after discharged from hospital into wastewater was clarified experimentally by using a new lab-scale conventional activated sludge (CAS) treatment reactor. The 43 target compounds belong to nine therapeutic classes (antivirals, antibacterials, anticancer drugs, psychotropics, antihypertensives, analgesic-antipyretics, contrast media, herbal medicines, and phytoestrogens) were selected with inclusion of 16 newly estimated compounds. The efficiency of the present reactor was estimated by comparing the reaction rate constant of the solid-water partition coefficients (log Kd) between liquid and solid samples and half-life during 48-h experiment obtained by using hospital effluents with those obtained by using STP wastewater. The results that no significant difference in removal efficiency was observed between both water samples (P > 0.05) indicate high reliability of the present lab-scale reactor. The actual rates of removal when hospital effluent was applied varied widely (mean, 59 ± 40%) independent of type of the pharmaceuticals. More than 90% of 17 compounds were removed after 8 h of treatment. However, the values for psychotropics (mean, 19 ± 26%) and contrast media (mean, 24 ± 17%) were generally low, indicating high stability. The log Kd values ranged from 1.3 to 4.8. Notably, clarithromycin, acridine, and glycitein could be removed in both liquid and solid phases. The dominant removal mechanisms were found to be different for individual pharmaceutical. These results suggest the effectiveness of introduction of the lab-scale biological treatment system for development of a new solution for discharge of pharmaceuticals from hospital.

A method for evaluating the pharmaceutical deconjugation potential in river water environments.

A new enzymatic assay method that uses deconjugation enzymes was developed to evaluate the presence and extent of conjugated pharmaceuticals in the form of glucuronide conjugates or sulphate conjugates in river environments. First, acetaminophen glucuronide (Ace Glu) and acetaminophen sulphate (Ace Sul) were used as model conjugated pharmaceuticals to determine the appropriate combination of deconjugation enzymes and reaction conditions, including temperature, duration and pH. Next, we applied the defined method to 19 pharmaceuticals grouped into nine therapeutic classes that were chosen based on previously detected levels and frequencies in sewage and river water. The enzymatic decomposition profile varied widely depending upon the enzyme preparations available. The effect of the water reaction temperature was small between 5 and 40 °C, and the reaction proceeded in for both glucuronide conjugates and sulphate conjugates at an approximately neutral pH (corresponding to usual river water conditions) within 1 h. Application of the method to environmental samples showed that some pharmaceuticals were present in both glucuronide conjugate and sulphate conjugated forms, although glucuronide conjugates were the primary forms in the river water environment. Water treatment systems at sewage treatment plants were found to be effective for the removal of these conjugated compounds. The present results should be valuable in the environmental risk assessment of conjugated pharmaceuticals and in keeping river environments clean. To the best of our knowledge, this is the first report that enables the evaluation of the pharmaceutical deconjugation potential in a river environment.

Validation of Medi·Ca EC Method for AOAC Research Institute Performance Tested MethodsSM Certification.

A ready-made dry medium method for Escherichia coli and coliform count, the Medi·Ca EC method, was compared with the most probable number (MPN) method using Brilliant Green Lactose Bile broth and E. coli broth (AOAC INTERNATIONAL Official MethodSM 966.24) for seven food matrixes: raw beef, raw pork, raw frozen pork, raw lamb, raw salmon, frankfurter sausage, and cooked ham. The mean difference between the two methods at each contamination level for each matrix was <0.5 log10, and the 95% confidence intervals for the mean differences fell within the range of -0.5 to 0.5, with the exception of a few cases in the independent laboratory study. sr and RSDr values of the Medi·Ca EC method were generally lower than those of the MPN method, and r2 ranged from 0.91 to 0.99. Product consistency and stability studies showed little variability between production lots and the shelf-life of 20 months. An incubation time within the range of 22-26 h did not adversely affect the results; however, variations in sample volume did affect final counts. These results showed that the Medi·Ca EC method is a reasonable alternative to the reference method for the selected food matrixes and makes it possible to simultaneously detect and enumerate E. coli and coliform in only 24 h.

Fate of new three anti-influenza drugs and one prodrug in the water environment.

We evaluated the environmental fate of new three anti-influenza drugs, favipiravir (FAV), peramivir (PER), and laninamivir (LAN), and an active prodrug of LAN, laninamivir octanoate (LANO), in comparison with four conventional drugs, oseltamivir (OS), oseltamivir carboxylate (OC), amantadine (AMN), and zanamivir (ZAN) by photodegradation, biodegradation, and sorption to river sediments. In addition, we conducted 9-month survey of urban rivers in the Yodo River basin from 2015 to 2016 (including the influenza season) to investigate the current status of occurrence of these drugs in the river environment. The results clearly showed that FAV and LAN rapidly disappeared through photodegradation (half-lives 1 and 8 h, respectively), followed by LANO which gradually disappeared through biodegradation (half-life, 2 days). The remained PER and conventional drugs were, however, persistent and transported from upstream to downstream sites. Rates of their sorption to river sediments were negligibly small. Detected levels remained were in the range from N.D. to 89 ng/L for the river waters and from N.D. to 906 ng/L in sewage effluent. However, all of the remained drugs were effectively removed by ozonation after chlorination at a sewage treatment plant. These findings suggest the importance of introducing ozonation for reduction of pollution loads in rivers, helping to keep river environments safe. To the best of our knowledge, this is the first evaluation of the removal effects of natural sunlight, biodegradation, and sorption to river sediments on FAV, PER, LAN, LANO, and a conventional drug, AMN.

Prognostic value of 2-[(18) F]fluoro-2-deoxy-D-glucose positron emission tomography for patients with oral squamous cell carcinoma treated with retrograde superselective intra-arterial chemotherapy and daily concurrent radiotherapy.

OBJECTIVE: To investigate whether 2-[(18) F]fluoro-2-deoxy-D-glucose (FDG) uptake of primary tumor in oral squamous cell carcinoma (OSCC) could predict prognosis. STUDY DESIGN: Sixty-nine patients with OSCC who underwent retrograde superselective intra-arterial chemoradiotherapy were recruited and underwent dual-time-point FDG positron emission tomography twice, before treatment and 4 weeks after treatment. FDG uptake was defined as the standardized uptake value (SUVmax). The retention index (RI) and the percent change in SUV (% change SUV), derived from the dual-time-point scan, were calculated. RESULTS: On univariate analysis, patients with high pre-SUV, RI, and percent change SUV values had significantly worse overall survival and disease-free survival compared with patients with low values. On multivariate analysis, high pre-RI (≥20.6%) and high percent change SUV (≥60.0%) (delayed-image) were associated with significantly worse overall survival. High pre-SUV (≥9.6) (delayed-image) and high pre-RI (≥20.6%) were associated with significantly shorter disease-free survival. CONCLUSIONS: Dual-time-point FDG positron emission tomography in OSCC provided prognostic information and predicted patient outcome.

Dai Nippon Printing Co., Ltd Medi·Ca CC for Enumeration of Coliform Bacteria.

A ready-made dry medium method for coliform count, the Medi·Ca CC method, was compared to the Violet Red Bile Agar method (Bacteriological Analytical Manual, Chapter 4, Enumeration of Escherichia coli and the Coliform Bacteria, Section G) for nine raw foods from four food categories: raw ground pork, raw lamb, raw ground chicken, raw tuna fillet, raw salmon fillet, raw shrimp, fresh peeled banana, fresh cut pineapple, and fresh cut apple. The 95% confidence interval for the mean difference between the two methods at each contamination level for seven matrixes from all four categories fell within the range of -0.50 to 0.50, and no statistical difference was observed at all three contamination levels for four matrixes from three categories. These results demonstrated that the Medi·Ca CC method is a reasonable alternative to the reference method for raw meat, raw poultry, raw fish, and fresh fruits.

Screening of specific inhibitors for human carboxylesterases or arylacetamide deacetylase.

Esterases catalyze the hydrolysis of therapeutic drugs containing esters or amides in their structures. Human carboxylesterase (CES) and arylacetamide deacetylase (AADAC) are the major enzymes that catalyze the hydrolysis of drugs in the liver. Characterization of the enzyme(s) responsible for drug metabolism is required in drug development and to realize optimal drug therapy. Because multiple enzymes may show a metabolic potency for a given compound, inhibition studies using chemical inhibitors are useful tools to determine the contribution of each enzyme in human tissue preparations. The purpose of this study was to find specific inhibitors for human CES1, CES2, and AADAC. We screened 542 chemicals for the inhibition potency toward hydrolase activities of p-nitrophenyl acetate by recombinant CES1, CES2, and AADAC. We found that digitonin and telmisartan specifically inhibited CES1 and CES2 enzyme activity, respectively. Vinblastine potently inhibited both AADAC and CES2, but no specific inhibitor of AADAC was found. The inhibitory potency and specificity of these compounds were also evaluated by monitoring the effects on hydrolase activity of probe compounds of each enzyme (CES1: lidocaine, CES2: CPT-11, AADAC: phenacetin) in human liver microsomes. Telmisartan and vinblastine strongly inhibited the hydrolysis of CPT-11 and/or phenacetin, but digitonin did not strongly inhibit the hydrolysis of lidocaine, indicating that the inhibitory potency of digitonin was different between recombinant CES1 and liver microsomes. Although we could not find a specific inhibitor of AADAC, the combined use of telmisartan and vinblastine could predict the responsibility of human AADAC to drug hydrolysis.

Indiplon is hydrolyzed by arylacetamide deacetylase in human liver.

Human arylacetamide deacetylase (AADAC) catalyzes the hydrolysis of some clinically used drugs, but the information available on its substrates is limited. To increase our knowledge of the AADAC substrates, we examined whether AADAC catalyzes the hydrolysis of indiplon, which was initially developed as a hypnotic sedative drug. It has been reported that approximately 30-40% of the administered indiplon was hydrolyzed to deacetylindiplon in humans, but the enzyme responsible for this hydrolysis had not been identified. We detected high levels of indiplon hydrolase activity in human liver microsomes (HLMs), but the levels found in human liver cytosol and plasma were scarcely detectable. Recombinant AADAC showed a high level of indiplon hydrolase activity, whereas recombinant carboxylesterase 1 (CES1) and 2 (CES2) showed marginal activity. The indiplon hydrolase activity of HLM was potently inhibited by vinblastine, a potent inhibitor of AADAC and CES2, but it was not inhibited by digitonin and telmisartan, inhibitors of CES1 and CES2, respectively. In a panel of 24 individual HLM samples, the indiplon hydrolase activities were significantly correlated with the hydrolase activities of flutamide, phenacetin, and rifampicin, which are known AADAC substrates. An HLM sample with a homozygous AADAC*3 allele, which was previously found to exhibit decreased enzyme activity, showed the lowest indiplon hydrolase activity among the 24 tested samples. Collectively, we found that human AADAC is responsible for the hydrolysis of indiplon. Thus, we can add indiplon to the list of human AADAC substrates.

Regulation of telomere length by G-quadruplex telomere DNA- and TERRA-binding protein TLS/FUS.

Mammalian telomeres comprise noncoding TTAGGG repeats in double-stranded regions with a single-stranded TTAGGG repeat 3' overhang and are bound by a multiprotein complex with a telomeric repeat-containing RNA (TERRA) containing a UUAGGG repeat as a G-quadruplex noncoding RNA. TLS/FUS is a human telomere-binding protein that was first identified as an oncogenic fusion protein in human myxoid and round-cell liposarcoma. Here, we show that the Arg-Gly-Gly domain in the C-terminal region of TLS forms a ternary complex with human telomere G-quadruplex DNA and TERRA in vitro. Furthermore, TLS binds to G-quadruplex telomere DNA in double-stranded regions and to G-quadruplex TERRA, which regulates histone modifications of telomeres and telomere length in vivo. Our findings suggest that the G-quadruplex functions as a scaffold for the telomere-binding protein, TLS, to regulate telomere length by histone modifications.

Contributions of arylacetamide deacetylase and carboxylesterase 2 to flutamide hydrolysis in human liver.

Flutamide, an antiandrogen drug, is widely used for the treatment of prostate cancer. The major metabolic pathways of flutamide are hydroxylation and hydrolysis. The hydrolyzed metabolite, 5-amino-2-nitrobenzotrifluoride (FLU-1), is further metabolized to N-hydroxy FLU-1, an assumed hepatotoxicant. Our previous study demonstrated that arylacetamide deacetylase (AADAC), one of the major serine esterases expressed in the human liver and gastrointestinal tract, catalyzes the flutamide hydrolysis. However, the enzyme kinetics in human tissue microsomes were not consistent with the kinetics by recombinant human AADAC. Thus, it seemed that AADAC is not the sole enzyme responsible for flutamide hydrolysis in human. In the present study, we found that recombinant carboxylesterase (CES) 2 could hydrolyze flutamide at low concentrations of flutamide. In the inhibition assay, the flutamide hydrolase activities at a flutamide concentration of 5 µM in human liver and jejunum microsomes were strongly inhibited by a selective CES2 inhibitor, 10 µM loperamide, with the residual activities of 22.9 ± 3.5 and 18.6 ± 0.7%, respectively. These results suggest that CES2 is also involved in the flutamide hydrolysis in human tissues. Using six individual human livers, the contributions of AADAC and CES2 to flutamide hydrolysis were estimated by using the relative activity factor. The relative contribution of CES2 was approximately 75 to 99% at the concentration of 5 µM flutamide. In contrast, the relative contribution of AADAC increased in parallel with the concentration of flutamide. Thus, CES2, rather than AADAC, largely contributed to the flutamide hydrolysis in clinical therapeutics.

A novel polymorphic allele of human arylacetamide deacetylase leads to decreased enzyme activity.

Human arylacetamide deacetylase (AADAC) is responsible for the hydrolysis of clinically used drugs such as flutamide, phenacetin, and rifamycins. Our recent studies suggested that human AADAC is a relevant enzyme pharmacologically and toxicologically. To date, the genetic polymorphisms that affect enzyme activity in AADAC have been unknown. In this study, we found single-nucleotide polymorphisms in the human AADAC gene in a liver sample that showed remarkably low flutamide hydrolase activity. Among them, g.13651G > A (V281I) and g.14008T > C (X400Q) were nonsynonymous. The latter would be predicted to cause a C-terminal one-amino acid (glutamine) extension. The AADAC*2 allele (g.13651G > A) was found in all populations investigated in this study (European American, African American, Korean, and Japanese), at allelic frequencies of 52.6 to 63.5%, whereas the AADAC*3 allele (g.13651G > A/g.14008T > C) was found in European American (1.3%) and African American (2.0%) samples. COS7 cells expressing AADAC.1 (wild-type) exhibited flutamide, phenacetin, and rifampicin hydrolase activities with intrinsic clearance (CLint) values of 1.31 ± 0.06, 1.00 ± 0.02, and 0.39 ± 0.02 µl x min(-1) x unit(-1), respectively. AADAC.2, which is a protein produced from the AADAC*2 allele, showed moderately lower or similar CLint values, compared with AADAC.1, but AADAC.3 showed substantially lower CLint values (flutamide hydrolase, 0.21 ± 0.02 µl x min(-1) x unit(-1); phenacetin hydrolase, 0.12 ± 0.00 µl x min(-1) x unit(-1); rifampicin hydrolase, 0.03 ± 0.01 µl x min(-1) x unit(-1), respectively). Microsomes from a liver sample genotyped as AADAC*3/AADAC*3 showed decreased enzyme activities, compared with those genotyped as AADAC*1/AADAC*1, AADAC*1/AADAC*2, and AADAC*2/AADAC*2. In conclusion, we found an AADAC allele that yielded decreased enzyme activity. This study should provide useful information on interindividual variations in AADAC enzyme activity.