A Case-Control Clinical Trial on a Deep Learning-Based Classification System for Diagnosis of Amyloid-Positive Alzheimer’s Disease

Objective@#A deep learning-based classification system (DLCS) which uses structural brain magnetic resonance imaging (MRI) to diagnose Alzheimer’s disease (AD) was developed in a previous recent study. Here, we evaluate its performance by conducting a single-center, case-control clinical trial. @*Methods@#We retrospectively collected T1-weighted brain MRI scans of subjects who had an accompanying measure of amyloid-beta (Aβ) positivity based on a 18F-florbetaben positron emission tomography scan. The dataset included 188 Aβ-positive patients with mild cognitive impairment or dementia due to AD, and 162 Aβ-negative controls with normal cognition. We calculated the sensitivity, specificity, positive predictive value, negative predictive value, and area under the receiver operating characteristic curve (AUC) of the DLCS in the classification of Aβ-positive AD patients from Aβ-negative controls. @*Results@#The DLCS showed excellent performance, with sensitivity, specificity, positive predictive value, negative predictive value, and AUC of 85.6% (95% confidence interval [CI], 79.8–90.0), 90.1% (95% CI, 84.5–94.2), 91.0% (95% CI, 86.3–94.1), 84.4% (95% CI, 79.2–88.5), and 0.937 (95% CI, 0.911–0.963), respectively. @*Conclusion@#The DLCS shows promise in clinical settings where it could be routinely applied to MRI scans regardless of original scan purpose to improve the early detection of AD.

Synergistic Renoprotective Effect of Melatonin and Zileuton by Inhibition of Ferroptosis via the AKT/mTOR/NRF2 Signaling in Kidney Injury and Fibrosis

According to recent evidence, ferroptosis is a major cell death mechanism in the pathogenesis of kidney injury and fibrosis.Despite the renoprotective effects of classical ferroptosis inhibitors, therapeutic approaches targeting kidney ferroptosis remain limited. In this study, we assessed the renoprotective effects of melatonin and zileuton as a novel therapeutic strategy against ferroptosis-mediated kidney injury and fibrosis. First, we identified RSL3-induced ferroptosis in renal tubular epithelial HK-2 and HKC-8 cells. Lipid peroxidation and cell death induced by RSL3 were synergistically mitigated by the combination of melatonin and zileuton. Combination treatment significantly downregulated the expression of ferroptosis-associated proteins, 4-HNE and HO-1, and upregulated the expression of GPX4. The expression levels of p-AKT and p-mTOR also increased, in addition to that of NRF2 in renal tubular epithelial cells. When melatonin (20 mg/kg) and zileuton (20 mg/kg) were administered to a unilateral ureteral obstruction (UUO) mouse model, the combination significantly reduced tubular injury and fibrosis by decreasing the expression of profibrotic markers, such as α-SMA and fibronectin. More importantly, the combination ameliorated the increase in 4-HNE levels and decreased GPX4 expression in UUO mice. Overall, the combination of melatonin and zileuton was found to effectively ameliorate ferroptosis-related kidney injury by upregulating the AKT/mTOR/ NRF2 signaling pathway, suggesting a promising therapeutic strategy for protection against ferroptosis-mediated kidney injury and fibrosis.

MRI Findings in Parkinson’s Disease: Radiologic Assessment of Nigrostriatal Degeneration

Parkinson’s disease (PD) is a movement disorder that develops due to degenerative loss of dopaminergic cells in the substantia nigra of the midbrain. Recent advances in MRI techniques have demonstrated various imaging findings that can reflect the underlying pathophysiological processes occurring in Parkinson’s disease. Many imaging studies have shown that such findings can assist in the diagnosis of Parkinson’s disease and its differentiation from atypical parkinsonism. In this review, we present MRI techniques that can be used in clinical assessment, such as nigrosome imaging and neuromelanin imaging, and we provide the detailed imaging features of Parkinson’s disease reflecting nigrostriatal degeneration.

Comparative analysis of immune related genes between domestic pig and germ-free minipig / 한국실험동물학회지

Recently, minipig has been considered as an animal model that is appropriate for human disease model to study toxicology, pharmacology, and xenotransplantation. Nevertheless, minipigs are bred in various environment according to their use. Here, we suggest that minipigs used for research should be bred in well-controlled facility, comparing immune status of pigs raised in different breeding environment. DNA microarray was performed with ear skin and placenta of Landrace domestic pigs (DPs) and Minnesota germ-free minipigs (GPs). Their immune transcriptome was analyzed by gene ontology (GO) annotation database, based on criteria of |log2 fold change| ≥1 with P ≤ 0.05. As a result, we found that immune related genes in the ear skin of DPs were highly activated, compared to GPs. On the other hand, no significant s were found in the placenta. Quantitative real-time PCR (qRT-PCR) was performed in five candidate immune genes. Their fold changes were consistent with the results from DNA microarray (P ≤ 0.05). In conclusion, we experimentally proved that porcine immune system was affected by different breeding environment, suggesting the importance of controlling microbes in animal room for the qualified research.

Comparative analysis of immune related genes between domestic pig and germ-free minipig / 한국실험동물학회지

Recently, minipig has been considered as an animal model that is appropriate for human disease model to study toxicology, pharmacology, and xenotransplantation. Nevertheless, minipigs are bred in various environment according to their use. Here, we suggest that minipigs used for research should be bred in well-controlled facility, comparing immune status of pigs raised in different breeding environment. DNA microarray was performed with ear skin and placenta of Landrace domestic pigs (DPs) and Minnesota germ-free minipigs (GPs). Their immune transcriptome was analyzed by gene ontology (GO) annotation database, based on criteria of |log2 fold change| ≥1 with P ≤ 0.05. As a result, we found that immune related genes in the ear skin of DPs were highly activated, compared to GPs. On the other hand, no significant s were found in the placenta. Quantitative real-time PCR (qRT-PCR) was performed in five candidate immune genes. Their fold changes were consistent with the results from DNA microarray (P ≤ 0.05). In conclusion, we experimentally proved that porcine immune system was affected by different breeding environment, suggesting the importance of controlling microbes in animal room for the qualified research.

Use of Molecular Imaging in Clinical Drug Development: a Systematic Review / 대한핵의학회잡지

BACKGROUND: Molecular imaging such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT) can provide the crucial pharmacokinetic-pharmacodynamic information of a drug non-invasively at an early stage of clinical drug development. Nevertheless, not much has been known how molecular imaging has been actually used in drug development studies.METHODS: We searched PubMed using such keywords as molecular imaging, PET, SPECT, drug development, and new drug, or any combination of those to select papers in English, published from January 1, 1990, to December 31, 2015. The information about the publication year, therapeutic area of a drug candidate, drug development phase, and imaging modality and utility of imaging were extracted.RESULTS: Of 10,264 papers initially screened, 208 papers met the eligibility criteria. The more recent the publication year, the bigger the number of papers, particularly since 2010. The two major therapeutic areas using molecular imaging to develop drugs were oncology (47.6%) and the central nervous system (CNS, 36.5%), in which efficacy (63.5%) and proof-of-concept through either receptor occupancy (RO) or other than RO (29.7%), respectively, were the primary utility of molecular imaging. PET was used 4.7 times more frequently than SPECT. Molecular imaging was most frequently used in phase I clinical trials (40.8%), whereas it was employed rarely in phase 0 or exploratory IND studies (1.4%).CONCLUSIONS: The present study confirmed the trend that molecular imaging has been more actively employed in recent clinical drug development studies although its adoption was rather slow and rare in phase 0 studies.

Use of Molecular Imaging in Clinical Drug Development: a Systematic Review / 대한핵의학회잡지

BACKGROUND@#Molecular imaging such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT) can provide the crucial pharmacokinetic-pharmacodynamic information of a drug non-invasively at an early stage of clinical drug development. Nevertheless, not much has been known how molecular imaging has been actually used in drug development studies.@*METHODS@#We searched PubMed using such keywords as molecular imaging, PET, SPECT, drug development, and new drug, or any combination of those to select papers in English, published from January 1, 1990, to December 31, 2015. The information about the publication year, therapeutic area of a drug candidate, drug development phase, and imaging modality and utility of imaging were extracted.@*RESULTS@#Of 10,264 papers initially screened, 208 papers met the eligibility criteria. The more recent the publication year, the bigger the number of papers, particularly since 2010. The two major therapeutic areas using molecular imaging to develop drugs were oncology (47.6%) and the central nervous system (CNS, 36.5%), in which efficacy (63.5%) and proof-of-concept through either receptor occupancy (RO) or other than RO (29.7%), respectively, were the primary utility of molecular imaging. PET was used 4.7 times more frequently than SPECT. Molecular imaging was most frequently used in phase I clinical trials (40.8%), whereas it was employed rarely in phase 0 or exploratory IND studies (1.4%).@*CONCLUSIONS@#The present study confirmed the trend that molecular imaging has been more actively employed in recent clinical drug development studies although its adoption was rather slow and rare in phase 0 studies.

Combination of In Vivo ¹²³IFP-CIT SPECT and Microdialysis Reveals an Antipsychotic Drug Haloperidol-induced Synaptic Dopamine Availability in the Rat Midbrain and Striatum

Synaptic dopamine (DA) is mainly regulated by the presynaptic DA transporter (DAT). Single-photon emission computerized tomography (SPECT) with the DAT radiotracer [¹²³I]FP-CIT assesses changes in synaptic DA availability when endogenous DA displaces [¹²³I]FP-CIT or competes for DAT. Here, we investigated the effects of haloperidol (HAL) and clozapine (CLZ) on [¹²³I]FP-CIT binding in the rat striatum and midbrain to assess the utility of [¹²³I]FP-CIT SPECT to quantify changes in synaptic DA availability. Rats underwent [¹²³I]FP-CIT SPECT after intraperitoneal administration of normal saline (vehicle), HAL (1 and 7 mg/kg), CLZ (10 and 54 mg/kg) and bupropion (BUP, a DAT blocker, 20 and 100 mg/kg). In the striatum and midbrain, percent differences in the nondisplaceable binding potential (BP(ND)) of [¹²³I]FP-CIT compared to the vehicle were calculated for the various drugs and doses. In another experiment, changes in endogenous striatal DA concentration were measured by in vivo microdialysis under the conditions used in the SPECT study. BUP dose-dependently occupied DAT at considerable levels. Compared to the vehicle, HAL decreased [¹²³I]FP-CIT BP(ND) in the striatum (−25.29% and −2.27% for 1 and 7 mg/kg, respectively) and to a greater degree in the midbrain (−58.74% and −49.64% for 1 and 7 mg/kg, respectively), whereas the CLZ-treated group showed a decrease in the midbrain (−38.60% and −40.38% for 10 and 54 mg/kg, respectively) but an increase in the striatum (18.85% and 38.64% for 10 and 54 mg/kg, respectively). Antipsychotic-induced changes in endogenous striatal DA concentrations varied across drugs and doses. The data demonstrate that [¹²³I]FP-CIT SPECT may be a useful preclinical technique for detecting increases in synaptic DA availability in the midbrain and striatum in response to HAL, with results comparable to those of in vivo microdialysis.

Regional Cerebral Glucose Metabolism in Novelty Seeking and Antisocial Personality: A Positron Emission Tomography Study

Novelty seeking (NS) and antisocial personality (ASP) are commonly exhibited by those who suffer from addictions, such as substance abuse. NS has been suggested to be a fundamental aspect of ASP. To investigate the neurobiological substrate of NS and ASP, we tested the relationship between regional cerebral glucose metabolism and the level of NS, determining the differences between individuals with and without ASP. Seventy-two healthy adults (43 males, mean age±SD=38.8±16.6 years, range=20~70 years; 29 females, 44.2±20.1 years, range=19~72 years) underwent resting-state brain positron emission tomography (PET) 40 minutes after 18F-fluorodeoxyglucose (FDG) injection. Within 10 days of the FDG PET study, participants completed Cloninger's 240-item Temperament and Character Inventory (TCI) to determine NS scores. Participants with and without ASP were grouped according to their TCI profiles. Statistical parametric mapping analysis was performed using the FDG PET and TCI profile data. NS scores positively correlated with metabolism in the left anterior cingulate gyrus and the insula on both sides of the brain and negatively correlated with metabolism in the right pallidum and putamen. Participants with ASP showed differences in cerebral glucose metabolism across various cortical and subcortical regions, mainly in the frontal and prefrontal areas. These data demonstrate altered regional cerebral glucose metabolism in individuals with NS and ASP and inform our understanding of the neurobiological substrates of problematic behaviors and personality disorders.

F-18 Sodium Fluoride Positron Emission Tomography/Computed Tomography for Detection of Thyroid Cancer Bone Metastasis Compared with Bone Scintigraphy

OBJECTIVE: The aim of the study was to compare the diagnostic performances of F-18 sodium fluoride positron emission tomography/computed tomography (bone PET/CT) and bone scintigraphy (BS) for the detection of thyroid cancer bone metastasis. MATERIALS AND METHODS: We retrospectively enrolled 6 thyroid cancer patients (age = 44.7 ± 9.8 years, M:F = 1:5, papillary:follicular = 2:4) with suspected bone metastatic lesions in the whole body iodine scintigraphy or BS, who subsequently underwent bone PET/CT. Pathologic diagnosis was conducted for 4 lesions of 4 patients. RESULTS: Of the 17 suspected bone lesions, 10 were metastatic and 7 benign. Compared to BS, bone PET/CT exhibited superior sensitivity (10/10 = 100% vs. 2/10 = 20%, p = 0.008), and accuracy (14/17 = 82.4% vs. 7/17 = 41.2%, p 0.05). CONCLUSION: Bone PET/CT may be more sensitive and accurate than BS for the detection of thyroid cancer bone metastasis.

Asymmetry of Dopamine D2/3 Receptor Availability in Dorsal Putamen and Body Mass Index in Non-obese Healthy Males

The dopaminergic system is involved in the regulation of food intake, which is crucial for the maintenance of body weight. We examined the relationship between striatal dopamine (DA) D2/3 receptor availability and body mass index (BMI) in 25 non-obese healthy male subjects using [11C]raclopride and positron emission tomography. None of [11C]raclopride binding potential (BP) values (measures of DA D2/3 receptor availability) in striatal subregions (dorsal caudate, dorsal putamen, and ventral striatum) in the left and right hemispheres was significantly correlated with BMI. However, there was a positive correlation between the right-left asymmetry index of [11C]raclopride BP in the dorsal putamen and BMI (r=0.43, p<0.05), suggesting that greater BMI is linked with higher receptor availability in the right dorsal putamen relative to the left in non-obese individuals. The present results, combined with previous findings, may also suggest neurochemical mechanisms underlying the regulation of food intake in non-obese individuals.

Biological Property of Recombinant Hemagglutinin-Neuraminidase Protein of Avian Paramyxovirus Type 6 Expressed by Recombinant Baculovirus

Hemagglutination inhibition (HI) test employing whole virus antigen is a prescribed serological test for serotyping, diagnosis and surveillance for avian paramyxoviruses (APMVs). For use as alternative to the virus antigen, hemagglutinin-neuraminidase (HN) protein gene of the wild duck isolate APMV-6/WB12-163FS of APMV serotype 6 (APMV-6) was amplified, cloned and expressed in Spodoptera frugiperda insect cells. The HN gene of 1,842 bps in length showed nucleotide and amino acid homology of 93.4% and 97.1%, respectively with that of APMV-6 prototype strain. Putative sialic acid binding motif and potential N-linked glycosylation sites were conserved. In Western blot analysis, the expressed protein had a molecular mass of 66 kDa and reacted specifically with antiserum to APMV-6. In addition, the recombinant HN protein showed biological properties such as hemagglutination (HA) and elution. The recombinant HN protein produced from infected cells showed high HA titers (approximately 2(13) HA unit/ml). The HA activity of the recombinant HN protein was inhibited by antisera to APMV-6. In cross HA inhibition test, the recombinant HN protein had the highest titers with antisera to homologous APMV serotype, although there was weak cross reaction with some of antisera to other APMV serotypes. Our results indicated that recombinant APMV-6 HN protein would have the potential as alternative to the APMV-6 antigen in HI assays.

Parkinsonism in corticobasal syndrome may not be primarily due to presynaptic dopaminergic deficiency

The clinical features of corticobasal degeneration (CBD) are quite asymmetric. The severity of clinical symptoms and dopamine transporter (DAT) bindings were less correlated compared to other parkinsonisms, suggesting that presynaptic nigrostriatal dopaminergic dysfunction may not explain extrapyramidal manifestations in CBD. Therefore we wanted to reexamine asymmetry and severity between DAT imaging and clinical findings. We studied patients meeting the diagnostic criteria for CBD based on clinical features. We collected their clinical information and imaging retrospectively. Seven patients were enrolled and all had asymmetric rigidity, bradykinesia and unilateral limb dystonia. These symptoms did not improve with levodopa. All patients showed symptoms bilaterally in the last visit, but asymmetry of clinical symptoms was remarkable at the time of DAT imaging. The DAT bindings were decreased in six subjects. However, one patient showed normal DAT binding. Four patients had a more evident DAT reduction on the side contralateral to the more clinically affected side, however, two patients had a more prominent reduction on the ipsilateral side. The symptoms that we regard as parkinsonian features in CBD are not only explained by presynaptic dopaminergic dysfunction. Our findings suggest that postsynaptic dopaminergic or nondopaminergic systems may play a major role in parkinsonian symptoms in corticobasal syndrome.

The Prevalence of Essential Tremor in Elderly Koreans

Essential tremor (ET) is one of the most common movement disorders. The prevalence of ET varies substantially among studies. In Korea, there is no well-designed epidemiological study of the prevalence of ET. Thus, we investigated the prevalence of ET in a community in Korea. Standardized interviews and in-person neurological examinations were performed in a random sample of the elderly aged 65 yr or older. Next, movement specialists attempted to diagnose ET clinically. People who showed equivocal parkinsonian features underwent dopamine transporter imaging using [123I]-FP-CIT SPECT, to differentiate ET from parkinsonism. A total of 714 subjects participated in this population-based study. Twenty six of these subjects were diagnosed as having ET. The crude prevalence of ET was 3.64 per 100 persons. Age, gender, or education period were not different between the ET patients and the non-ET subjects. The prevalence of ET was slightly lower than those reported in previous studies. Further studies including more subjects are warranted.

Bone Positron Emission Tomography with or without CT Is More Accurate than Bone Scan for Detection of Bone Metastasis

OBJECTIVE: Na18F bone positron emission tomography (bone PET) is a new imaging modality which is useful for the evaluation of bone diseases. Here, we compared the diagnostic accuracies between bone PET and bone scan for the detection of bone metastasis (BM). MATERIALS AND METHODS: Sixteen cancer patients (M:F = 10:6, mean age = 60 +/- 12 years) who underwent both bone PET and bone scan were analyzed. Bone PET was conducted 30 minutes after the injection of 370 MBq Na18F, and a bone scan was performed 3 hours after the injection of 1295 MBq 99mTc-hydroxymethylene diphosphonate. RESULTS: In the patient-based analysis (8 patients with BM and 8 without BM), the sensitivities of bone PET (100% = 8/8) and bone scan (87.5% = 7/8) were not significantly different (p > 0.05), whereas the specificity of bone PET (87.5% = 7/8) was significantly greater than that of the bone scan (25% = 2/8) (p < 0.05). In the lesion-based analysis (43 lesions in 14 patients; 31 malignant and 12 benign), the sensitivity of bone PET (100% = 31/31) was significantly greater than that of bone scan (38.7% = 12/31) (p < 0.01), and the specificity of bone PET (75.0% = 9/12) was also significantly higher than that of bone scan (8.3% = 1/12) (p < 0.05). The receiver operating characteristic curve analysis showed that bone PET was significantly more accurate than the bone scan in the patient (p = 0.0306) and lesion (p = 0.0001) based analyses. CONCLUSION: Na18F bone PET is more accurate than bone scan for BM evaluation.

Striatal Dopaminergic Functioning in Patients with Sporadic and Hereditary Spastic Paraplegias with Parkinsonism

Sporadic spastic paraplegia (SSP) and hereditary spastic paraplegia (HSP) belong to a clinical and genetically heterogeneous group of disorders characterized by progressive spasticity and weakness in the lower extremities. The symptoms are associated with pyramidal tract dysfunction and degeneration of the corticospinal tracts. Parkinsonism is uncommon in SSP/HSP patients. However, both disorders are associated with damage to the nigrostriatal dopaminergic system. In the present study, the clinical features of patients with SSP/HSP were investigated, and nigrostriatal dopaminergic binding potential was assessed using dopamine transporter (DAT) single-photon emission computer tomography (SPECT). Nine patients with spastic paraplegia participated in the present study. The subjects underwent DAT SPECT using the agent [2-[[2-[[[3-(4-chlorophenyl)-8-methyl-8-azabicyclo[3,2,1]oct-2-yl]methyl](2-mercaptoethyl)amino]ethyl]amino]ethanethiolato (3-)-N2,N20,S2,S20]oxo-[IR-(exo-exo)])-[99mTc]technetium ([99mTc]TRODAT-1). The [99mTc]TRODAT-1 SPECT images of five patients appeared normal, whereas the images of four patients revealed reduced striatal ligand uptake. Among the four patients with reduced uptake, two had parkinsonism, and one exhibited periodic limb movements and restless leg syndrome. Our DAT SPECT imaging study shows that reduced DAT density may be observed in patients with parkinsonism. The results of the present study offer an explanation for the spectrum of spastic paraplegia symptoms and the progression of the disorder.

A Novel Aromatic Fluorine-18 Labeling Method Using Iodonium Salts Precursor / 핵의학분자영상

As many new drug substances contained various aromatic rings and fluorine attached to an electron rich aromatic ring or on the meta-position, a strategy towards improvement in aromatic fluorination of these compounds is highly desirable. The introduction of fluorine-18 onto aromatic rings showed in the limited condition containing electron withdrawing group (EWG) on the para- or ortho-position to get reasonable radiochemical yield so far. No-carrier added (NCA) [18F]fluoroarene syntheses by iodonium salts recently reported that has the potential to greatly increase the yield in systems or positions that normally not reactive enough to give sufficient yields in simple model reaction. This review describes the methodological approach towards effective aromatic fluorination by diaryliodonium salts and future prospects in an application of novel PET radiotracer.

Prediction of Splint Therapy Efficacy Using Bone Scan in Patients with Unilateral Temporomandibular Disorder / 핵의학분자영상

PURPOSE: It is not known whether bone scan is useful for the prediction of the prognosis of patients with temporomandibular disorders (TMD). The aim of the present study was to identify useful prognostic markers on bone scan for the pre-therapeutic assessment of patients with unilateral TMD. MATERIALS AND METHODS: Between January 2005 and July 2007, 55 patients (M:F=9:46; mean age, 34.7+/-14.1 y) with unilateral TMD that underwent a pre-therapeutic bone scan were enrolled. Uptake of Tc-99m HDP in each temporomandibular joint (TMJ) was quantitated using a 13X13 pixel-square region-of-interest over TMJ and parietal skull area as background. TMJ uptake ratios and asymmetric indices were calculated. TMD patients were classified as improved or not improved and the bone scan findings associated with each group were investigated. RESULTS: Forty-six patients were improved, whereas 9 patients were not improved. There was no significant difference between the two groups of patients regarding the TMJ uptake ratio of the involved joint, the TMJ uptake ratio of the non-involved joint, and the asymmetric index (p>0.05). However, in a subgroup analysis, the patients with an increased uptake of Tc-99m HDP at the disease-involved TMJ, by visual assessment, could be easily identified by the asymmetric index; the patients that improved had a higher asymmetric index than the patients that did not improve (1.32+/-0.35 vs. 1.08+/-0.04, p=0.023). CONCLUSION: The Tc-99m HDP bone scan may help predict the prognosis of patients with unilateral TMD after splint therapy when the TMD-involved joint reveals increased uptake by visual assessment.

Chronic Osteomyelitis in Sternum Mimicking Bone Metastasis of Lung Cancer Patient / 핵의학분자영상

Primary sternal osteomyelitis without predisposing factors is a rare condition, and it is hardly differentiated from metastatic bone tumor especially in patient with the history of primary malignancy because osteomyelities shares frequently common findings with metastatic bone lesion on 18F-FDG PET and bone scan. Although there have been several publications of primary osteomyelitis mimicking bone metastasis in the spine or extremities, we report a case of primary sternal osteomyelitis in the patient with lung cancer, which has, to our knowledge, not been reported before.

The Clinical Features of Pertussis in Infancy / 소아감염

PURPOSE: Pertussis was very common in the past, but reported cases have dramatically decreased. The improvement of vaccination programs and unreadiness of laboratory confirmation seems to have developed this situation. This study investigated the frequency of pertussis among infants with a paroxysmal cough and compared the clinical characteristics between infants with and without pertussis. METHODS: Between June and November 2006, 27 infants admitted to the hospital that were 15-90 days old with a history of a cough for more than seven days were enrolled. The cough was described as: paroxysmal, whooping, and post-tussive vomiting. PCR and cultures for Bordetella pertussis with nasopharyngeal aspirates were obtained. The patients were divided into two groups: (1) the pertussis group that had positive results by PCR or culture; (2) the control group that had negative results by PCR and culture. Clinical and laboratory characteristics were compared between the two groups. RESULTS: Among the 27 cases, five (18.5%) were finally diagnosed with pertussis. Only one out of the five pertussis cases was initially diagnosed with a pertussis-like syndrome on admission. Compared to the group without pertussis, the pertussis group had a significantly higher frequency of: no fever (P=0.043), a paroxysmal cough (P=0.040), cyanosis (P=0.001), non-immunized status for DTaP (P=0.047), normal auscultation (P=0.028), normal chest X-ray findings (P=0.027), high absolute lymphocyte count (P=0.039), and low CRP (P=0.046). The patients with the diagnosis of pertussis had a significantly longer duration of coughing (27.2+/-10.6 vs. 12.6+/-5.6 days, P=0.039). CONCLUSION: Pertussis should be suspected in any infant with typical symptoms of pertussis in addition to: a persistent cough without fever, accompanied by paroxysms or cyanosis prior to the age of DTaP immunization. Active laboratory confirmation should be carried out to confirm more cases with pertussis.