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Biomedical subjects

M L Lai

Publications and source records attributed to M L Lai.

At least 19 recordsLinked to original sources
PubMed2006

The diagnostic value for differentiated thyroid carcinoma metastases of thyroglobulin (Tg) measurement in washout fluid from fine-needle aspiration biopsy of neck lymph nodes is maintained in the presence of circulating anti-Tg antibodies.

OBJECTIVE: Serum thyroglobulin (Tg) is the marker of differentiated thyroid carcinoma (DTC) after total thyroidectomy, but its value is limited by the interference of anti-Tg antibodies (TgAb). Detection of Tg in fine-needle aspiration biopsy (Tg-FNAB) washout fluid is used to identify neck DTC recurrences/metastases, but the interference of serum TgAb in this procedure is unknown. PATIENTS AND METHODS: Seventy-three patients (41 after surgery for thyroid cancer and 32 with thyroid nodules) evaluated for suspicious cervical lymph nodes were retrospectively reviewed. Tg was assayed by immunoradiometric assay or chemiluminescent assay in ultrasound-guided FNAB used for cytology. Serum TgAb were detected by passive agglutination or chemiluminescent assay. On the basis of preliminary data obtained in lymphadenitis, Tg-FNAB more than 36 ng/ml and more than 1.7 ng/ml (in the presence or absence of thyroid gland, respectively) was considered as indicative of metastasis. RESULTS: In 51 TgAb-negative patients, Tg-FNAB was positive in 15 (12 with malignant and three with nondiagnostic cytology), all with histologically confirmed DTC metastases. Of the remaining 36 patients with negative Tg-FNAB, 30 had nonsuspicious and six had suspicious cytology. Histology of the latter showed four undifferentiated thyroid cancer metastases and two lymphadenitis. In 22 TgAb-positive patients, Tg-FNAB was positive in 14 (12 with malignant and two with nondiagnostic cytology), all with histologically confirmed DTC metastases. CONCLUSIONS: Clinical performance of Tg-FNAB appears to be not substantially affected by TgAb, and this procedure remains superior to cytology in the identification of DTC neck metastases. However, cytology should always be performed because, irrespective of TgAb, Tg is undetectable in FNAB from undifferentiated metastases.

Adolescent↗
PubMed2005

High prevalence of suspicious cytology in thyroid nodules associated with positive thyroid autoantibodies.

OBJECTIVE: We assessed the association between thyroid autoimmunity and thyroid cancer in a retrospective series of unselected thyroid nodules submitted to fine-needle aspiration cytology (FNAC) to avoid the selection bias of surgical series. SUBJECTS AND METHODS: Ultrasound (US)-guided FNACs were obtained from 590 unselected consecutive patients with single thyroid nodules and positive (ATA + , n = 197) or negative (ATA - , n = 393) serum anti-thyroid antibody (ATA). Cytological results were classified in three classes of increased risk of malignancy: low risk or benign (class II); indeterminate risk (class III); and suspect or malignant (class IV). RESULTS: A higher prevalence of class III (28.9% vs 21.4%, P < 0.05) and class IV (18.8% vs 9.2%, P < 0.001) and lower prevalence of class II (52.3% vs 69.5%, P < 0.001) were found in ATA + vs ATA - nodules respectively. By multivariate logistic regression analysis ATA + conferred a significant risk (odds ratio (OR): 2.29 (95% confidence interval (CI): 1.39-3.76)) for class IV cytology independently from age and sex. In 106 patients where thyroidectomy was carried out, thyroid cancer was found in 54/61 (88.5%) patients with class IV nodules (with similar positive predictive value for cancer in ATA + (96.4%) and ATA- (81.8%) nodules), in 6/31 (19.3%) of class III nodules (all ATA - ) and in none of 14 class II nodules. Non-specific cytological atypias from hyperplastic nodules in lymphocytic thyroiditis probably accounted for the different prevalence of cancer in class III ATA + and ATA - nodules. Histologically proven thyroid cancer (mostly papillary) was then observed in a higher proportion (27/197 = 13.7%) of ATA + , when compared with ATA - nodules (33/393 = 8.4%, P = 0.044), but the significance of this finding is limited by the low number of class II nodules operated on. CONCLUSIONS: The presence of ATA + confers an increased risk of suspicious or malignant cytology in unselected thyroid nodules. Since ATA + is not responsible for increased false-positive class IV FNAC, our study provides indirect evidence supporting a significant association between thyroid carcinoma and thyroid autoimmunity, although further studies with a different design are needed for a definitive histological proof.

Adult↗
PubMed2003

The usefulness of 99mTc-SestaMIBI scan in the diagnostic evaluation of thyroid nodules with oncocytic cytology.

OBJECTIVE: To assess the relevance of (99m)Tc-SestaMIBI (MIBI) scan in the diagnostic evaluation of thyroid nodules with oncocytic cytology. SUBJECTS AND METHODS: Twenty-four patients with a single (or prevalent) 'cold' solid nodule with Hurthle cells (HC) at fine needle aspiration cytology (FNAC) were studied. Cytological diagnosis of oncocytic metaplasia (OM) or HC tumor (HCT) was made when HC on the smear were comprised 10-75%, or >75%. Nodules concentrating MIBI at early and late (2 h after washout) stages were considered MIBI-positive. In all cases histological findings were obtained after total thyroidectomy. RESULTS: FNAC was malignant or suspect for malignancy in 16 cases (six HCT and 10 OM) and not suspect in eight (two HCT and six OM). Histological examination revealed 14 malignant tumors (11 HCT and three OM), and 10 benign thyroid lesions (three HCT and seven OM). Sensitivity of FNAC for malignancy was 92.8% and specificity was 70.0%; HCT were identified by FNAC in only 35.7% and OM in 70.0% of cases. No significant difference in MIBI positivity was found between malignant and benign thyroid nodules. The highest percentage of MIBI positivity was found in HCT (78.5%), but MIBI-positive nodules were also observed in thyroid lesions with HC metaplasia (40.0%). CONCLUSIONS: MIBI scintiscan has no value in differentiating malignant from benign HC thyroid neoplasias. Most HCT are MIBI-positive, but this scan is not sufficiently specific to differentiate true HC neoplasias from other thyroid lesions showing HC at FNAC, although an MIBI-negative scan strongly supports the absence of true HCT.

Adenoma, Oxyphilic↗
PubMed2001

Functional mutation in the promoter region of thrombomodulin gene in relation to carotid atherosclerosis.

Thrombomodulin is an important endothelial anticoagulant protein that decreases thrombin activity and activates protein C. Our recent study has shown that the G-33A promoter mutation of thrombomodulin gene is associated with coronary artery disease. This study was conducted to determine whether the G-33A mutation in the promoter region of thrombomodulin gene is a genetic risk factor for ischemic stroke or carotid atherosclerosis. The functional significance of this mutation was also evaluated. We recruited 333 patients (mean age 64 years, 59% male) with ischemic stroke and 257 age- and sex-matched controls. In all study participants, carotid atherosclerosis was assessed by Duplex scanning, and thrombomodulin G-33A promoter mutation was detected by single-strand conformation polymorphism. Luciferase reporter gene assay was used to assess the influence of this mutation on thrombomodulin promoter activity. There was no significant difference in the thrombomodulin G-33A mutation frequency (GA+AA genotypes) between the stroke and the control groups (18.3 vs. 24. 1%, P=0.105). The G-33A mutation frequency was also similar between the study participants with and without carotid atherosclerosis (22.2 vs. 19.8%, P=0.550). When only younger subjects (age </=60 years) were included in the analysis, however, we found the mutation occurred more frequently in participants with carotid atherosclerosis (33.3 vs. 17.3%, odds ratio [OR]=2.38, 95% confidence interval [CI]=1.16-4.90, P=0.027). Multiple logistic regression analyses showed that only diabetes mellitus (OR=3.11, 95% CI=1.33-7.30, P=0.009) and G-33A mutation (OR=2.46, 95% CI=1.14-5.29, P=0.021) were associated independently with carotid atherosclerosis in younger subjects. As assessed by luciferase reporter gene assays, the contructs bearing the G-33A mutation showed a significant decrease (36+/-12%) in transcriptional activity in comparison with the wild type constructs. Our findings suggest that G-33A mutation reduces the thrombomodulin promoter activity and is associated with carotid atherosclerosis in younger subjects.

Aged↗
PubMed2001

Novel mutations of CYP3A4 in Chinese.

Human cytochrome P450 3A4 is a major P450 enzyme in the liver and gastrointestinal tract. It plays important roles in the metabolism of a wide variety of drugs, some endogenous steroids, and harmful environmental contaminants. CYP3A4 exhibits a remarkable interindividual activity variation as high as 20-fold. To investigate whether the interindividual variation in CYP3A4 levels can be partly explained by genetic polymorphism, we analyzed DNA samples from 102 Chinese subjects by polymerase chain reaction (PCR)-single-strand conformation polymorphism analysis for novel point mutation in the CYP3A4 coding sequence and promoter region. Using PCR and directed sequencing method to establish the complete intron sequence of CYP3A4 from leukocytes, the complete genomic sequence from exon 1 through 13 of CYP3A4 was determined and published in the GenBank database (accession no. AF209389). CYP3A4-specific primers were designed accordingly. After PCR-single-strand conformation polymorphism and restriction fragment length polymorphism screening, we found three novel mutations; two are point mutations and one is insertion. The first variant allele (CYP3A4*4), an Ile118Val change, was found in 3 of 102 Chinese subjects. The next allele (CYP3A4*5), which causes a Pro218Arg amino acid change, was found in 2 of 102 subjects. We found an insertion in A(17776), designated as CYP3A4*6, which causes frame shift and an early stop codon in exon 9, in one heterozygous subject. We also investigated the CYP3A4 activity in these mutant subjects by measuring the morning spot urinary 6beta-hydroxycortisol to free cortisol ratio with the enzyme-linked immunosorbent assay method. When compared with healthy Chinese population data, the 6beta-hydroxycortisol to free cortisol ratio data suggested that these alleles (CYP3A4*4, CYP3A4*5, and CYP3A4*6) may decrease the CYP3A4 activity. Incidences of these mutations in Chinese subjects are rare. The prevalence of these point mutations in other ethnic groups and its effect on the metabolic activity of CYP3A4 remain to be further evaluated.

Alleles↗
PubMed2001

Recurrent hypertensive intracerebral hemorrhage among Taiwanese.

Hypertensive intracerebral hemorrhage (HICH) was once thought to be a one-time event with very rare recurrence, but recent studies have revealed that the recurrent hemorrhage due to hypertension is not unusual. The purpose of this study was to determine the clinical characteristics of HICH among Taiwanese. From June 1988 to December 1999, 1421 HICH patients were admitted to our hospital. Among them, 68 patients (4.8%) had recurrent HICH. We reviewed their medical records and computed tomographic findings. There were 46 males and 22 females (M/F = 2.1) with a mean age of 59.9 +/- 11.9 years at the onset of the second hemorrhage. The median interval between the first two hemorrhages was 22.5 months (range: 1-107 months). Most of the recurrence was within two years of the first hemorrhage (within 1 year in 27.9%, within 1-2 years in 25%). The location of the second hemorrhage was typical for HICH (putamen in 44.1%, thalamus in 33.8%, cerebellum in 5.9%, pons in 4.4%, and caudate nucleus in 1.5%) except for 7 patients (10.3%) who had lobar hematoma. Forty-nine patients (72%) had both hemorrhages located in the supratentorium and in most of them (40 patients) the recurrent HICH occurred contralaterally to the first one. Putaminal-thalamic pattern was the most common (23.5%), followed by the putaminal-putaminal pattern (20.6%). The mortality rate of the second HICH was 17.6%. Seven patients (10.3%) experienced more than 2 episodes of hemorrhages. This report found that the recurrent HICH was not rare among Taiwanese. A substantial proportion (19.1%) of recurrence was after 5 years. The male predominance and risk factor for recurrent HICH require further study.

Adult↗
PubMed2000

Midbrain hemorrhage presenting with trochlear nerve palsy.

A 40-year-old normotensive man suddenly developed diplopia, tinnitus and a burning sensation on the left side of his body while driving a motorcycle. He did not complain of headache, nausea or vomiting. Neurologic examination revealed left trochlear nerve palsy and impaired pinprick, temperature and joint position sensation of the left limbs. There was no ptosis or motor deficit. He had a mild bleeding diathesis due to alcoholic liver cirrhosis. Computerized tomography and magnetic resonance image of the brain disclosed hemorrhages in the right midbrain tectum and the left temporal lobe. After nine months of observation, there was nearly complete recovery of symptoms, except for mild residual diplopia. From a literature review, only nine case of midbrain tectal hemorrhage involving the inferior colliculus have been reported. These patients had a unique clinical presentation. Diplopia due to trochlear nerve palsy, either unilateral or bilateral, was present in all of the cases. Tinnitus and sensory disturbance contralateral to the lesion side were very common. Only three patients had risk factors for hemorrhage, including bleeding diathesis, hypertension and vascular anomalies. In the majority of patients, no underlying causes were detected. The outcome was favorable with conservative treatment.

Adult↗
PubMed1999

Glial cell line-derived neurotrophic factor-like immunoreactivity in human trigeminal ganglion and nucleus.

Glial cell line-derived neurotrophic factor (GDNF) is shown by immunohistochemistry in human trigeminal sensory system from 22 weeks of gestation to adulthood. In the trigeminal ganglion, a distinct subpopulation of GDNF-positive neurones is observed, which amounts to about 15% at early pre-term and adult ages and peaks to around 30% at perinatal ages. Labelled neurones are mostly small- and medium-sized. Occasionally, Schwann and satellite cells are stained. GDNF/substance P (SP) and GDNF/calcitonin gene-related peptide (CGRP) double stained neurones occur at all ages examined, whereas GDNF/trkA coexistence can be observed in pre- and full-term newborns only. Centrally, GDNF-immunostained fibers and terminal-like structures are mainly restricted to the spinal trigeminal nucleus, where they are codistributed with SP and CGRP. In the subnucleus caudalis, positive neurones can also be observed both in the superficial laminae and in the magnocellular part, with higher frequency in adults. These results suggest that GDNF may play a functional role in human trigeminal primary sensory neurones throughout life and provide indication for its possible involvement in the regulation of pain-related neuronal circuits in human trigeminal sensory system.

Adult↗
PubMed1999

Neurotrophin-like immunoreactivity in the human hippocampal formation.

The immunohistochemical occurrence and localisation of the neurotrophins nerve growth factor, brain-derived neurotrophic factor (BDNF), neurotrophin-4, and neurotrophin-3 is described in the human post-mortem hippocampal formation from subjects aged 23 weeks of gestation to 68 years. Labeled neuronal cell bodies and processes were detectable for each neurotrophin at all examined ages with age-related changes in their distribution pattern. As a general rule, a higher number of immunoreactive perikarya was found in subjects at pre- and perinatal ages than in adults. At variance with the other neurotrophins, the BDNF antiserum labelled also extensive nerve fibre systems, whose occurrence and distribution widened with age. The results obtained provide a morphological ground in support to the concept that the neurotrophins play a functional role in the human hippocampal circuitry throughout life.

Aged↗
PubMed1999

Pharmacokinetics of metoprolol enantiomers in Chinese subjects of major CYP2D6 genotypes.

OBJECTIVE: CYP2D6 mediates both alpha-hydroxylation and O-demethylation of metoprolol. In Chinese subjects, CYP2D6*1 (the wild-type) alleles are relatively uncommon. Subjects with P34S (C188-->T188) and S486T (G4268-->C4268) mutations (CYP2D6J or CYP2D6*10A) are more frequently seen. Recently, the CYP2D6*2 (CYP2D6L) genotype that results in R296C (C2938-->T2938) and S486T mutations was also found important. In this study, metoprolol pharmacokinetics was investigated in subjects of these 3 major genotypes. METHODS: Allele-specific polymerase chain reaction was used to differentiate CYP2D6*1 and CYP2D6*2 alleles from the common CYP2D6*10A allele in Chinese. Subjects with both CYP2D6*1 and CYP2D6*2 have homozygous C188 in the exon 1, whereas subjects with CYP2D6*10A have T188. Metoprolol pharmacokinetics was compared in 16 C188 subjects (6 homozygous CYP2D6*1 subjects and 10 heterozygous CYP2D6*1/CYP2D6*2 subjects), 12 heterozygous C/T188 subjects, and 12 homozygous T188 subjects. RESULTS: No significant difference in plasma concentration profile or urinary alpha-hydroxymetoprolol excretion could be found among subjects with R296C polymorphism (CYP2D6*1/CYP2D6*2). Therefore data from subjects with CYP2D6*1 and CYP2D6*2 were pooled to compare with data from subjects with CTP2D6*10A. The area under plasma concentration curves (AUC) of S-metoprolol was 1411+/-116 (mean +/- SEM, n = 16), 1899+/-120 (n = 12), and 3588+/-435 (n = 12) nmol x hr/L for homozygous C188, heterozygous C/T188, and homozygous T188 subjects, respectively. The urinary recovery of all 4 alpha-hydroxymetoprolol diastereomers was significantly lower in T188 subjects than in C188 subjects. CONCLUSION: The P34S polymorphism but not the R296C polymorphism resulted in higher metoprolol plasma concentrations and lower urinary metoprolol metabolite levels in Chinese subjects. This finding suggests that a lower dose of metoprolol may be used in subjects with T188 mutation (CYP2D6*10A allele).

Administration, Oral↗
PubMed1998

Alpha-1-antichymotrypsin immunoreactivity in papillary carcinoma of the thyroid gland.

AIM: Papillary thyroid carcinoma (PTC) is the most common malignant tumour of the thyroid gland. The immunohistochemical profile of PTC is characterized by immunoreactivity of tumour cells for cytokeratins, thyroglobulin, vimentin, EMA and S100 protein. Recently, the presence of a serum protease inhibitor, alpha-1-antitrypsin (A1AT), has been demonstrated in tumour cells of PTC. The aim of our study was to test immunoreactivity of PTC for another inhibitor of proteases, alpha-1-antichymotrypsin (A1ACT). METHODS AND RESULTS: Serial paraffin sections of nine consecutive cases of PTC were tested with anti-A1AT and anti-A1ACT antibodies. No immunoreactivity for A1AT and A1ACT was found in the normal thyroid tissue surrounding each tumour. In seven out of nine cases, tumour cells of PTC showed cytoplasmic immunoreactivity for A1ACT. In two cases, A1ACT was detected even in the nuclei. Immunoreactivity for A1AT was found only in three cases. Two cases of PTC showed no staining for both A1ACT and A1AT. No significant correlation of A1ACT staining was found with various prognostic indices (age of patients, histological pattern, tumour size, presence of regional lymph node metastases). The two cases showing a lack of staining for both A1ACT and A1AT showed a more aggressive clinical behaviour. CONCLUSIONS: Our preliminary study shows that A1ACT is expressed by tumour cells in a large proportion of papillary carcinomas of the thyroid gland. Its significance remains, to the best of our knowledge, still unknown. The observation of a more aggressive behaviour in the two cases characterized by the absence of immunoreactivity for both A1ACT and A1AT suggests that the presence or absence of protease inhibitors could play a role in controlling tumour progression in PTC.

Adolescent↗
PubMed1998

Developmental profile of a caltrin-like protease inhibitor, P12, in mouse seminal vesicle and characterization of its binding sites on sperm surface.

We examined the developmental profile of a kazal-type trypsin inhibitor (P12) of Mr 6126 in mouse seminal vesicle, characterized its binding sites on the surface of sperm, and assessed its effect on Ca2+ uptake by spermatozoa. Among the genital tracts of adult mice, P12 was found only in the male accessory glands including seminal vesicle, coagulating gland, and prostate. It was immunolocalized on the luminal epithelium of the primary and secondary folds in both the seminal vesicle and coagulating gland, and on the folds projecting into the lumen of the glandular alveolus in the prostate. The protein and its RNA message in seminal vesicle did not appear in the prepubertal period, but expression coincided with maturation. Castration of adult mice resulted in cessation of P12 expression. Treatment of the castrated mice with testosterone propionate in corn oil restored the protein expression in the seminal vesicle. Spermatozoa collected from caudal epididymis were devoid of P12. Cytochemical study illustrated a P12-binding region on the anterior acrosomes of cells preincubated with P12. Analysis of equilibrium data from the binding assay using 125I-P12 with a Scatchard plot showed a single type of P12-binding sites on sperm, with an apparent dissociation constant of 70.15 +/- 5.25 nM and the capacity of 1.49 +/- 0.06 x 10(6) binding sites/cell. The protein could serve as a calcium transport inhibitor to suppress a great extent of Ca2+ uptake by spermatozoa. The immunohistochemical staining patterns of testis revealed that the P12-binding sites appeared on postmeiotic cells such as spermatids and spermatozoa, but were absent in Leydig cells, Sertoli cells, spermatogonia, and spermatocytes in seminiferous tubules.

Animals↗
PubMed1998

Ischemic stroke in a young woman with ovarian hyperstimulation syndrome.

We present a case of right middle cerebral artery occlusion after a controlled ovarian hyperstimulation regimen and cryopreserved embryo transfer (ET) in a previously healthy 22-year-old woman. The patient suffered from nausea and progressive abdominal distension 8 days after ET. Under the diagnosis of ovarian hyperstimulation syndrome, she was treated with hypertonic solution, albumin infusion, and paracentesis, with some improvement. Left hemiparesis and dysarthria occurred suddenly on the fourth day of hospitalization, 11 days after ET. The neurologic deficits progressed to complete hemiplegia within a few hours. Computed tomography of the head showed infarction in the territory of the right middle cerebral artery. Magnetic resonance angiography revealed occlusion of the main trunk of the right middle cerebral artery. Laboratory studies showed leukocytosis with neutrophil predominance and a hypercoagulable state. The pregnancy was terminated because of progressive tachycardia, dyspnea, and increased abdominal girth despite supportive treatment. The neurologic deficits remained stationary at the time of discharge. This case emphasizes that the recent advent of ovulation induction and assisted reproductive techniques is a newly recognized cause of devastating cerebral infarction in otherwise healthy women.

Adult↗
PubMed1997

Effectiveness of low-dose ASA in prevention of secondary ischemic stroke, the ASA Study Group in Taiwan.

This randomized double-blind controlled study was carried out to investigate the effect of 100 mg acetylsalicylic acid (ASA) per day on the secondary prevention of ischemic stroke. Patients who suffered a first ischemic stroke from 13 participating hospitals were enrolled. They were independent or only partially dependent in activities of daily living and all had received brain CT for diagnosis. Eligible patients were randomly allocated to the 100 mg ASA or the nicametate citrate (a vasodilator) groups, and trial medications were started within three to six weeks after the onset of stroke. The primary end point was cerebral reinfarction, and intracranial hemorrhage was classified as an adverse event. Four hundred and sixty-six patients participated in this study; and 222 cases (136 males and 86 females) were allocated to the ASA group while 244 cases (150 males and 94 females) were assigned to the nicametate group. No significant difference in baseline characteristics between the two groups was observed. Cerebral reinfarction developed 6.3% (14/222) in the ASA group and 11.9% (29/244) in the nicametate group. According to the Cox's proportional hazards model, the estimated risk ratio (ASA group vs. nicametate group) was 0.538, with a 95% confidence interval of 0.284-1.019. The result was of borderline statistical significance. The risk for cerebral reinfarction was reduced by almost 50% among those who took 100 mg ASA versus those who took nicametate.

Aged↗
PubMed1997

Apolipoprotein B gene polymorphisms in Taiwanese ischemic stroke patients.

We analyzed the AluI restriction fragment length polymorphism (RFLP) of the apolipoprotein B (apoB) gene to determine the association between AluI allelic distribution and the occurrence of ischemic stroke in Taiwan. A total of 44 healthy volunteers and 159 ischemic stroke patients were included in the study. The allele frequency of AluI was very similar in the two groups, 0.87 in the patient group and 0.89 in the control group, for the major allele A-. The distribution of A-/A-, A-/A+, and A+/A+ genotypes of the patients was not significantly different from that of the controls. Among ischemic stroke patients, the A+ allele of the AluI restriction site was significantly associated with elevated apoB levels. The results of this study suggest that the presence of the rare AluI RFLP may contribute to an elevated plasma apoB level, which is a known risk factor for ischemic stroke.

Aged↗
PubMed1997

Genetic polymorphism of monoamine oxidase B and susceptibility of Parkinson's disease.

BACKGROUND: Monoamine oxidase B (MAO-B) may play a role in the progression and cause of Parkinson's disease (PD), given consideration of the biochemistry and pathophysiology of the disease, and experiments on primates and humans. Assuming that the structural gene determines enzyme activity, an association study was undertaken to examine MAO-B genetic polymorphisms and look for the unique MAO-B gene alleles which occurred at a higher frequency in PD patients. METHODS: Sixty-five PD patients, diagnosed according to the criteria set by a Core Assessment Program for Intracerebral Transplantations Committee, and 108 healthy controls were enrolled in this study. Genomic DNA was extracted from peripheral leukocytes by using a puregene kit. Polymerase chain reaction (PCR) was used to amplify the MAO-B genome. The PCR products were screened by restriction enzyme Hae III digestion and analyzed by single-stranded conformational polymorphism (SSCP). RESULTS: Two bands with different mobility shifts, defined as MAO-B allele 1 and allele 2, were observed in SSCP analysis. Neither genotypes nor allelic frequencies of MAO-B showed a significant difference between PD patients and controls in our study. CONCLUSIONS: Polymorphism of MAO-B genome was demonstrated in this study. It failed to show an association of a genetic marker with PD. However, this did not necessarily exclude the MAO-B locus from playing a role in causing PD because a polymorphism different from the one evaluated here may show some disease association.

Aged↗