Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 41
Filter
2.
Qual Life Res ; 30(9): 2521-2530, 2021 Sep.
Article in English | MEDLINE | ID: mdl-33783675

ABSTRACT

PURPOSE: Sleep problems are prevalent among the general population and can cause various health problems, which may lead to decreased quality of life. However, little is known about nonrestorative sleep and its implications. This study aimed to examine the association between nonrestorative sleep and health-related quality of life (HRQL) in Chinese adults. METHODS: Data were collected through a cross-sectional study of 500 adults in Hong Kong (66.4% female, average age of 39 years). The Short-Form-12 Health Survey version 2 (SF-12v2), Nonrestorative Sleep Scale (NRSS), Pittsburgh Sleep Quality Index, ENRICHD Social Support Instrument, Patient Health Questionnaire, Perceived Stress Scale, and Hospital Anxiety and Depression Scale were administered. Objective sleep parameters were based on participants' sleep condition over 1 week, as measured using an ActiGraph GT9X Link. RESULTS: Mean standardized scores for the physical component summary (PCS) and mental component summary (MCS) of the SF-12v2 and the NRSS were 50.33 ± 6.50, 49.00 ± 9.03, and 64.77 ± 12.75, respectively. After adjusting for sociodemographic and lifestyle characteristics, sleep quality, objective sleep parameters, social support, somatic symptoms, stress, anxiety, and depression, NRSS scores were associated with PCS (b = 0.12, 95%CI: 0.06 to 0.18, p < 0.001) and MCS (b = 0.08, 95%CI: 0.02 to 0.15, p = 0.013) scores. Furthermore, associations of NRSS score with PCS as well as MCS scores were stronger in women than in men. CONCLUSION: Nonrestorative sleep is a potentially modifiable risk factor for poor HRQL. Thus, interventions to relieve or decrease nonrestorative sleep could be beneficial for improving HRQL.


Subject(s)
Quality of Life , Sleep Wake Disorders , Adult , China/epidemiology , Cross-Sectional Studies , Female , Humans , Male , Quality of Life/psychology , Sleep , Sleep Wake Disorders/epidemiology , Surveys and Questionnaires
4.
Qual Life Res ; 29(9): 2585-2592, 2020 Sep.
Article in English | MEDLINE | ID: mdl-32418061

ABSTRACT

PURPOSE: Previous research has suggested the essential unidimensionality of the 12-item traditional Chinese version of the Nonrestorative Sleep Scale (NRSS). This study aimed to develop a short form of the traditional Chinese version of the NRSS without compromising its reliability and validity. METHODS: Data were collected from 2 cross-sectional studies with identical target groups of adults residing in Hong Kong. An iterative Wald test was used to assess differential item functioning by gender. Based on the generalized partial credit model, we first obtained a shortened version such that further shortening would result in substantial sacrifice of test information and standard error of measurement. Another shortened version was obtained by the optimal test assembly (OTA). The two shortened versions were compared for test information, Cronbach's alpha, and convergent validity. RESULTS: Data from a total of 404 Chinese adults (60.0% female) who had completed the Chinese NRSS were gathered. All items were invariant by gender. A 6-item version was obtained beyond which the test performance substantially deteriorated, and a 9-item version was obtained by OTA. The 9-item version performed better than the 6-item version in test information and convergent validity. It had discrimination and difficulty indices ranging from 0.44 to 2.23 and - 7.58 to 2.13, respectively, and retained 92% of the test information of the original 12-item version. CONCLUSION: The 9-item Chinese NRSS is a reliable and valid tool to measure nonrestorative sleep for epidemiological studies.


Subject(s)
Psychometrics/methods , Quality of Life/psychology , Sleep/physiology , Adolescent , Adult , Aged , Aged, 80 and over , Asian People , Cross-Sectional Studies , Female , Humans , Language , Male , Middle Aged , Young Adult
5.
J Endocrinol Invest ; 43(3): 347-355, 2020 Mar.
Article in English | MEDLINE | ID: mdl-31529391

ABSTRACT

PURPOSE: Accurate subtyping of the primary aldosteronism into aldosterone-producing adenoma (APA) and idiopathic adrenal hyperplasia (IAH) is important to direct for specific treatment modalities. The objective of the study was to compare the clinical and biochemical parameters of APA and IAH patients to derive a Clinical Prediction Score reliably predicting APA from IAH. METHODS: This was a retrospective multi-centre study recruiting 38 APA patients and 42 IAH patients from four major hospitals in Hong Kong using database from Surgical Outcomes Monitoring and Improvement Programme and Clinical Data Analysis and Reporting System. Their clinical and biochemical parameters were evaluated. RESULTS: Patients in APA group were younger than IAH group (mean age 48.6 ± 9.2 vs. 57.1 ± 7.3 years old, p < 0.001), had more suppressed renin before saline infusion in saline infusion test (SIT) (median 0.19 [IQR 0.15-0.37] vs. 0.39 [IQR 0.19-0.69] ng/mL/h, p = 0.01), and higher aldosterone level after saline infusion in SIT (median 674 [IQR 498-1000] vs. 327 [IQR 242-483] pmol/L, p < 0.001). A clinical prediction score using three parameters was devised, comprising age at diagnosis < 50 years, PRA before saline infusion in SIT ≤ 0.26 ng/mL/h, and aldosterone level after saline infusion in SIT ≥ 424 pmol/L. A score of 2 would predict APA with a sensitivity of 84.2% and specificity of 88.1%, and a score of 3 would predict APA with a sensitivity of 31.6% and specificity of 100%. CONCLUSIONS: Clinical Prediction Score based on the combination of age at diagnosis, PRA, and aldosterone level in the saline infusion tests could reliably predict APA from IAH.


Subject(s)
Adrenal Cortex Neoplasms/complications , Adrenocortical Adenoma/complications , Aldosterone/blood , Hyperaldosteronism/etiology , Adrenal Cortex Neoplasms/blood , Adrenocortical Adenoma/blood , Adult , Age Factors , Female , Humans , Hyperaldosteronism/blood , Hyperplasia/complications , Male , Middle Aged , Retrospective Studies
6.
Ultrasound Obstet Gynecol ; 55(3): 303-309, 2020 03.
Article in English | MEDLINE | ID: mdl-31325336

ABSTRACT

OBJECTIVE: To compare the proportion of women achieving a desired ovarian response following ovarian stimulation when gonadotropin dosing was determined based on antral follicle count (AFC) vs serum anti-Müllerian hormone (AMH) level, in women undergoing in-vitro fertilization (IVF) using the gonadotropin-releasing hormone (GnRH) antagonist protocol. METHODS: This was a randomized double-blind trial carried out in a university-affiliated assisted reproduction unit. A total of 200 women undergoing their first IVF cycle using the GnRH-antagonist protocol between April 2016 and February 2018 were randomized to determination of gonadotropin dosing based on either AFC or serum AMH level measured in the pretreatment cycle 1 month before the IVF cycle. Patients underwent IVF as per our center's standard protocol. The proportion of subjects achieving a desired ovarian response, defined as retrieval of six to 14 oocytes, was compared between the two study arms. Subgroup analysis of patients with baseline AFC > 5 and those with baseline AFC ≤ 5 was performed. Concordance in AFC and AMH categorization between the pretreatment cycle and the ovarian-stimulation cycle was assessed using Cohen's kappa (κ). RESULTS: There was no significant difference in the proportion of patients achieving a desired ovarian response between the AFC (54%) and AMH (49%) groups (P = 0.479). The median number of oocytes retrieved was nine vs seven (P = 0.070), and the median follicular output rate was 0.54 vs 0.55 (P = 0.764) in the AFC and AMH groups, respectively. Similar findings were observed on subgroup analysis of subjects with AFC ≤ 5 and AFC > 5 at the start of ovarian stimulation (P > 0.05 for all comparisons). There was moderate concordance between AFC and AMH measured in the pretreatment cycle and the stimulation cycle (κ = 0.478 and 0.587, respectively). CONCLUSION: The proportion of women achieving a desired ovarian response following ovarian stimulation using the GnRH-antagonist protocol is similar when the gonadotropin-dosing algorithm used is based on AFC or serum AMH level. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.


Comparación del recuento de folículos sinusales y el nivel de la hormona antimulleriana en el suero para la determinación de la dosis de gonadotrofina en la fecundación in vitro: ensayo aleatorizado OBJETIVO: Comparar la proporción de mujeres que logran una respuesta ovárica deseada tras la estimulación del ovario cuando se determinó la dosis de gonadotrofina en función del recuento de folículos sinusales (AFC, por sus siglas en inglés) frente al nivel de la hormona antimulleriana (HAM) en el suero, en mujeres que se sometieron a una fecundación in vitro (FIV) mediante el protocolo de antagonistas de la hormona liberadora de gonadotropina (GnRH, por sus siglas en inglés). MÉTODOS: Se trata de un ensayo aleatorizado doble ciego realizado en una unidad de reproducción asistida afiliada a una universidad. Un total de 200 mujeres que se sometieron a su primer ciclo de FIV y utilizaron el protocolo de antagonistas de la GnRH entre abril de 2016 y febrero de 2018 fueron asignadas al azar a la determinación de la dosis de gonadotrofina basada en el nivel de AFC o de HAM en suero, medidos en el ciclo de pretratamiento un mes antes del ciclo de FIV. Las pacientes se sometieron a una FIV según el protocolo estándar de nuestro centro. La proporción de mujeres que lograron una respuesta ovárica deseada, definida como la recuperación de seis a 14 ovocitos, se comparó entre las dos ramas del estudio. Se realizó un análisis de subgrupos de las pacientes con AFC de base >5 y de aquellas con AFC de base ≤5. La concordancia en la categorización del AFC y la HAM entre el ciclo de pretratamiento y el ciclo de estimulación ovárica se evaluó utilizando la medida estadística kappa de Cohen (κ). RESULTADOS: No hubo diferencias significativas en la proporción de pacientes que lograron una respuesta ovárica deseada entre los grupos de AFC (54%) y HAM (49%) (P=0,479). La mediana del número de ovocitos recuperados fue de nueve frente a siete (P=0,070), y la mediana de la tasa de producción folicular fue de 0,54 frente a 0,55 (P=0,764) en los grupos AFC y HAM, respectivamente. Se observaron hallazgos similares en el análisis de subgrupos de pacientes con AFC ≤5 y AFC >5 al comienzo de la estimulación ovárica (P>0,05 para todas las comparaciones). Se observó una concordancia moderada entre el AFC y la HAM medidos en el ciclo de pretratamiento y el ciclo de estimulación (κ=0,478 y 0,587, respectivamente). CONCLUSIÓN: La proporción de mujeres que logran una respuesta ovárica deseada después de la estimulación ovárica utilizando el protocolo de antagonistas de la GnRH es similar cuando el algoritmo de dosificación de gonadotrofina utilizado se basa en el nivel del AFC o de la HAM en suero.


Subject(s)
Anti-Mullerian Hormone/blood , Fertilization in Vitro/methods , Gonadotropins/administration & dosage , Hormone Antagonists/administration & dosage , Ovarian Follicle/growth & development , Adult , Algorithms , Double-Blind Method , Female , Gonadotropin-Releasing Hormone/antagonists & inhibitors , Humans , Ovulation Induction/methods , Pregnancy , Treatment Outcome
7.
Clin Exp Immunol ; 197(2): 205-213, 2019 08.
Article in English | MEDLINE | ID: mdl-31251396

ABSTRACT

Type 2 diabetes is a global health priority, given that it is driven, in part, by an ageing population, the role of immune senescence has been overlooked. This is surprising, as the functional impairments of senescent T cells show strong similarities to patients with hyperglycaemia. Immune senescence is typified by alterations in T cell memory, such as the accumulation of highly differentiated end-stage memory T cells, as well as a constitutive low-grade inflammation, which drives further immune differentiation. We show here in a preliminary study that people living with type 2 diabetes have a higher circulating volume of senescent T cells accompanied with a higher level of systemic inflammation. This inflammatory environment drives the expression of a unique array of chemokine receptors on senescent T cells, most notably C-X-C motif chemokine receptor type 2. However, this increased expression of migratory markers does not translate to improved extravasation owing to a lack of glucose uptake by the T cells. Our results therefore demonstrate that the presence of senescent T cells has a detrimental impact on immune function during type 2 diabetes.


Subject(s)
Aging/immunology , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , Cellular Senescence/immunology , Diabetes Mellitus, Type 2/immunology , Aged , Cell Movement/immunology , Female , Glucose/metabolism , Humans , Immunologic Memory/immunology , Inflammation/immunology , Insulin Resistance/physiology , Lymphocyte Count , Male , Middle Aged , Platelet Count , Receptors, Chemokine/analysis
9.
Andrologia ; 49(10)2017 Dec.
Article in English | MEDLINE | ID: mdl-28670753

ABSTRACT

Human varicella zoster virus (VZV) is a member of the herpes virus family and affects humans only. Information about the presence of the virus in the semen samples of men affected by chickenpox is rather limited in the literature. Here, we reported a husband was affected by VZV during in vitro fertilisation treatment of his wife treated in our centre. The semen sample was checked for the presence of VZV by the PCR technique. The PCR result found no detectable viral DNA in the semen sample. The semen sample was then used for conventional IVF insemination and subsequently a healthy baby boy was born. This single case report suggests that the semen sample of men affected by chickenpox may be safe to use for assisted reproduction methods during the VZV infective period.


Subject(s)
Chickenpox/virology , Herpesvirus 3, Human/isolation & purification , Semen/virology , Adult , Fertilization in Vitro , Humans , Male
10.
Health Promot Chronic Dis Prev Can ; 36(11): 235-242, 2016 Nov.
Article in English, French | MEDLINE | ID: mdl-27882858

ABSTRACT

INTRODUCTION: To examine temporal variations in parental and peer influences on adolescent physical activity (PA) and whether these variations predicted changes in PA. METHODS: We analyzed data from Years 1, 2 and 3 of the COMPASS study. Participants were 22 909 students in Grades 9 to 12 (mean age [years] = 15.42 ± 1.12, 46% boys, 85% White), who had completed the following survey items on 2 or more consecutive occasions: age, sex, grade, race/ethnicity, moderate-to-vigorous physical activity (MVPA), parental encouragement and parental instrumental support for PA, and number of active peers. We used a linear-mixed model to investigate longitudinal effects of parental and peer influences on changes in square-root transformed average MVPA. We used a generalized-estimating-equations (GEE) model to investigate compliance with Canadian PA guidelines for youth. These models included parental encouragement, instrumental support and number of active peers as time-varying predictors, adjusting for sociodemog raphic factors and grade as covariates, and accounting for the clustering within children and schools. RESULTS: We found that adolescents perceived significantly less parental encouragement and instrumental support and reported fewer active peers as they got older. In addition, the adjusted models suggest that, for a one-unit increase in the score of parental encouragement, parental instrumental support and number of active peers, average MVPA significantly increased by 0.22 units, 0.23 units and 0.16 units, respectively. For the same one-unit increase, adjusted odds of an adolescent complying with the PA guidelines increased by 9%, 4% and 6%, respectively. CONCLUSION: Promoting parental support and facilitating the formation and maintenance of a physically active friendship network may play an important role in attenuating declines in PA during adolescence.


INTRODUCTION: Examiner les variations temporelles de l'influence des parents et des pairs sur l'activité physique des adolescents et vérifier si elles prédisent des changements dans l'activité physique. MÉTHODOLOGIE: Nous avons analysé les données des années 1, 2 et 3 de l'étude COMPASS. Les participants étaient 22 909 élèves de la 9e à la 12e année (âge moyen [ans] = 15,42 ± 1,12; 46 % de garçons; 85 % d'élèves blancs) ayant répondu à deux reprises ou plus et de façon consécutive aux éléments suivants de l'enquête : âge, sexe, année de scolarité, race ou origine ethnique, activité physique modérée à vigoureuse (APMV), encouragement parental et soutien instrumental des parents à l'égard de l'activité physique (AP) et enfin nombre de pairs actifs. Nous avons utilisé un modèle linéaire mixte pour étudier les effets longitudinaux de l'influence des parents et des pairs sur les changements dans l'APMV moyenne avec transformation racine carrée. Nous avons fait appel à un modèle d'équation d'estimation généralisée (EEG) pour examiner l'observance des Directives canadiennes en matière d'activité physique à l'intention des jeunes. Dans ces modèles, l'encouragement parental, le soutien instrumental des parents et le nombre de pairs actifs ont été traités à titre de prédicteurs variant dans le temps. Les modèles ont été ajustés en fonction des facteurs sociodémographiques et de l'année de scolarité (covariables) et ont tenu compte des regroupements des enfants et au sein des écoles. RÉSULTATS: Nous avons constaté que les adolescents, à mesure qu'ils vieillissent, perçoivent significativement moins d'encouragement et de soutien instrumental de leurs parents et déclarent un moins grand nombre de pairs actifs. De plus, les modèles ajustés semblent indiquer que, pour une augmentation d'une unité du score relatif à l'encouragement parental, au soutien instrumental des parents et au nombre de pairs actifs, l'APMV moyenne a considérablement augmenté, de respectivement 0,22, 0,23 et 0,16 unités. Pour l'augmentation d'une unité, la probabilité ajustée qu'un adolescent respecte les directives en matière d'AP s'est accrue de respectivement 9 %, 4 % et 6 %. CONCLUSION: Le fait de promouvoir le soutien parental et de contribuer à la création et au maintien d'un réseau d'amis physiquement actifs pourrait jouer un rôle important dans l'atténuation du déclin de l'activité physique durant l'adolescence.


Subject(s)
Adolescent Behavior , Exercise , Parent-Child Relations , Peer Influence , Adolescent , Canada , Female , Guidelines as Topic , Humans , Linear Models , Longitudinal Studies , Male , Prospective Studies
11.
Clin Pharmacol Ther ; 99(5): 555-61, 2016 May.
Article in English | MEDLINE | ID: mdl-26599303

ABSTRACT

Thioamides antithyroid-drugs (ATDs) are important in hyperthyroid disease management. Identification of the susceptibility locus of ATD-induced agranulocytosis is important for clinical management. We performed a genome-wide association study (GWAS) involving 20 patients with ATD-induced agranulocytosis and 775 healthy controls. The top finding was further replicated. A single-nucleotide polymorphism (SNP), rs185386680, showed the strongest association with ATD-induced agranulocytosis in GWAS (odds ratio (OR) = 36.4; 95% confidence interval (CI) = 12.8-103.7; P = 1.3 × 10(-24)) and replication (OR = 37; 95% CI = 3.7-367.4; P = 9.6 × 10(-7)). HLA-B*38:02:01 was in complete linkage disequilibrium with rs185386680. High-resolution HLA typing confirmed that HLA-B*38:02:01 was associated with carbimazole (CMZ)/methimazole (MMI)-induced agranulocytosis (OR = 265.5; 95% CI = 27.9-2528.0; P = 2.5 × 10(-14)), but not associated with propylthiouracil (PTU). The positive and negative predictive values of HLA-B*38:02:01 in predicting CMZ/MMI-induced agranulocytosis were 0.07 and 0.999. Approximately 211 cases need to be screened to prevent one case. Screening for the risk allele will be useful in preventing agranulocytosis in populations in which the frequency of the risk allele is high.


Subject(s)
Agranulocytosis/chemically induced , Antithyroid Agents/adverse effects , Carbimazole/adverse effects , HLA-B Antigens/genetics , Methimazole/adverse effects , Agranulocytosis/genetics , Antithyroid Agents/administration & dosage , Carbimazole/administration & dosage , Case-Control Studies , Female , Genome-Wide Association Study , Humans , Linkage Disequilibrium/genetics , Methimazole/administration & dosage , Polymorphism, Single Nucleotide , Predictive Value of Tests , Propylthiouracil/administration & dosage , Propylthiouracil/adverse effects
12.
Lupus ; 25(6): 637-44, 2016 May.
Article in English | MEDLINE | ID: mdl-26700182

ABSTRACT

Longitudinal studies on cognitive impairment in patients with past history of neuropsychiatric lupus (NPSLE) are scant. In this study, NPSLE patients and matched disease and healthy controls were examined with a full battery of neuropsychological tests that covered eight cognitive domains at two time-points 12 months apart. Confounders, including depressive and anxiety symptoms, were measured by the Hospital Anxiety and Depression Scale. Eighteen NPSLE, 18 patients with systemic lupus erythematosus (SLE) who had no previous cerebral involvement (non-NPSLE) and 16 healthy subjects were recruited. NPSLE patients consistently reported more cognitive and anxiety symptoms than non-NPSLE patients over both time-points. NPSLE patients had significantly worse memory, simple and complex attention compared to non-NPSLE patients, among which memory remained significantly impaired after adjustment for confounders. NPSLE patients demonstrated a trend of higher raw scores of some neurocognitive tests upon re-evaluation over 12 months, but NPSLE patients did not demonstrate any practice effect. In conclusion, NPSLE patients had significantly worse and persistently impaired memory and learning deficits compared to non-NPSLE patients over the 12-month re-assessment period.


Subject(s)
Cognition Disorders/epidemiology , Lupus Erythematosus, Systemic/complications , Lupus Vasculitis, Central Nervous System/complications , Memory Disorders/epidemiology , Adult , Anxiety/epidemiology , Anxiety/etiology , Case-Control Studies , Cognition Disorders/etiology , Female , Humans , Learning Disabilities/epidemiology , Learning Disabilities/etiology , Longitudinal Studies , Lupus Vasculitis, Central Nervous System/epidemiology , Male , Memory Disorders/etiology , Middle Aged , Neuropsychological Tests , Psychiatric Status Rating Scales
14.
Obes Rev ; 14(8): 645-58, 2013 Aug.
Article in English | MEDLINE | ID: mdl-23601571

ABSTRACT

The purpose of this review was to examine the factors that predict the development of excessive fatness in children and adolescents. Medline, Web of Science and PubMed were searched to identify prospective cohort studies that evaluated the association between several variables (e.g. physical activity, sedentary behaviour, dietary intake and genetic, physiological, social cognitive, family and peer, school and community factors) and the development of excessive fatness in children and adolescents (5-18 years). Sixty-one studies met the eligibility criteria and were included. There is evidence to support the association between genetic factors and low physical activity with excessive fatness in children and adolescents. Current studies yielded mixed evidence for the contribution of sedentary behaviour, dietary intake, physiological biomarkers, family factors and the community physical activity environment. No conclusions could be drawn about social cognitive factors, peer factors, school nutrition and physical activity environments, and the community nutrition environment. There is a dearth of longitudinal evidence that examines specific factors contributing to the development of excessive fatness in childhood and adolescence. Given that childhood obesity is a worldwide public health concern, the field can benefit from large-scale, long-term prospective studies that use state-of-the-art measures in a diverse sample of children and adolescents.


Subject(s)
Adiposity/physiology , Diet , Life Style , Obesity/epidemiology , Adolescent , Child , Child, Preschool , Female , Humans , Male , Obesity/etiology , Risk Factors , Social Environment
15.
J Chem Theory Comput ; 5(9): 2257-64, 2009 Sep 08.
Article in English | MEDLINE | ID: mdl-26616612

ABSTRACT

We evaluate the accuracy of density functional theory quantum calculations of biomolecular subsystems using a simple electrostatic embedding scheme. Our scheme is based on dividing the system of interest into a primary and secondary subsystem. A finite difference discretization of the Kohn-Sham equations is used for the primary subsystem, while its electrostatic environment is modeled with a simple one-electron potential. Force-field atomic partial charges are used to generate smeared Gaussian charge densities and to model the secondary subsystem. We illustrate the utility of this approach with calculations of truncated dipeptide chains. We analyze quantitatively the accuracy of this approach by calculating atomic forces and comparing results with full QM calculations. The impact of the choice made in terminating dangling bonds at the frontier of the QM region is also investigated.

16.
Environ Mol Mutagen ; 47(2): 132-46, 2006 Mar.
Article in English | MEDLINE | ID: mdl-16258923

ABSTRACT

An isomeric series of heterocyclic amines related to one found in heated muscle meats was investigated for properties that predict their measured mutagenic potency. Eleven of the 12 possible 2-amino-trimethylimidazopyridine (TMIP) isomers were tested for mutagenic potency in the Ames/Salmonella test with bacterial strain TA98, and resulted in a 600-fold range in potency. Structural, quantum chemical, and hydropathic data were calculated on the parent molecules and the corresponding nitrenium ions of all of the tested isomers to establish models for predicting the potency of the unknown isomer. The principal determinants of higher mutagenic potency in these amines are: (1) a small dipole moment, (2) the combination of b-face ring fusion and N3-methyl group, (3) a lower calculated energy of the pi electron system, (4) a smaller energy gap between the amine HOMO and LUMO orbitals (Pearson "softness"), and (5) a more stable nitrenium ion. Based on predicted potency from the average of six regression models, the isomer not yet synthesized and tested is expected to have a mutagenic potency of 0.77 revertants/microg in tester strain TA98, which is near the low end of the potency range of the isomers.


Subject(s)
Computer Simulation , Models, Statistical , Pyridines/chemistry , Pyridines/toxicity , Quantitative Structure-Activity Relationship , Salmonella/drug effects , Isomerism , Molecular Structure , Mutagenicity Tests
17.
Mol Hum Reprod ; 11(12): 843-6, 2005 Dec.
Article in English | MEDLINE | ID: mdl-16421213

ABSTRACT

Previous studies analysing the incidences of mitochondrial DNA (mtDNA) deletions and mtDNA content in unfertilized oocytes in relation to donors' age have been controversial. The objective of the study was to compare these two parameters in unfertilized oocytes and relate them to the donors' age. Fifty-two women donated 155 unfertilized metaphase II (MII) oocytes. The incidence of 4977 bp deletion was 34.6%, and the mtDNA copy number was 598 350 +/- 265 862. Women >or=35 years of age had a significantly higher incidence of 4977 bp deletion, lower mtDNA copy number, higher FSH level and poorer ovarian response when compared with younger women. The mtDNA copy number was negatively correlated with the donor's age. The higher incidence of mtDNA deletion and lower mtDNA copy number in older women suggested that these two parameters may reflect ovarian ageing.


Subject(s)
DNA, Mitochondrial/genetics , Oocytes/physiology , Sequence Deletion , Adult , DNA, Mitochondrial/isolation & purification , Female , Fertilization , Humans , Infertility, Female/genetics , Menstrual Cycle , Polymerase Chain Reaction
18.
J Assist Reprod Genet ; 20(6): 227-33, 2003 Jun.
Article in English | MEDLINE | ID: mdl-12877254

ABSTRACT

PURPOSE: To investigate the relationship between CAG repeat length in the androgen receptor gene and impaired spermatogenesis in Hong Kong Chinese population. METHODS: The CAG repeat region was amplified by polymerase chain reaction (PCR) in 85 nonobstructive azoospermic or severe oligozoospermic men, and 45 fertile males. The number of CAG repeat was analyzed by DNA sequencing. Serum FSH, LH, and testosterone levels were also determined in these men. RESULTS: Among nonobstructive azoospermic males, three men (5.7%) possessed short CAG repeats (< 16), and three (5.7%) other men possessed long CAG repeats (> 30). Short CAG repeats (< 16) were also found in two severe oligozoospermic males (6.3%). The incidence of infertile men with short or long CAG repeats is significantly higher in the azoospermic group (p = 0.03) but not in the severe oligozoospermic group (p = 0.17) when compared with the fertile controls CONCLUSION: Our data suggest an association between CAG repeat lengths and impaired spermatogenesis in azoospermic males in our population.


Subject(s)
Infertility, Male/genetics , Receptors, Androgen/genetics , Spermatogenesis/genetics , Trinucleotide Repeats/genetics , Adolescent , Adult , Asian People , Fertility/genetics , Hong Kong , Humans , Male , Middle Aged , Oligospermia/genetics
19.
Hong Kong Med J ; 9(1): 43-7, 2003 Feb.
Article in English | MEDLINE | ID: mdl-12547956

ABSTRACT

This paper presents the first two successful cases of pre-implantation genetic diagnosis in Hong Kong and discusses the indications and the advantages over prenatal diagnosis. Patients should be informed about the procedure and extensively counselled about the possibility of misdiagnosis and the need for conventional prenatal diagnosis during pregnancy.


Subject(s)
Preimplantation Diagnosis , Adult , Counseling , Embryo Transfer , Female , Hong Kong , Humans , Male , Prenatal Diagnosis
20.
Proc Natl Acad Sci U S A ; 98(17): 9527-32, 2001 Aug 14.
Article in English | MEDLINE | ID: mdl-11493680

ABSTRACT

A molecular dynamics study was performed to compare the differences in the active-site dynamics of the wild-type and W137F mutant enzymes of 4-chlorobenzoyl-CoA dehalogenase. Only in the wild-type simulation are conformations formed between the catalytic Asp-145 and 4-chlorobenzoyl-CoA, which resemble the ab initio calculated gas-phase transition-state geometry. In the W137F simulation, the hydrogen bond formed between His-90 and Asp-145 persisted throughout the simulation, causing the carboxylate of Asp-145 to be distant from the benzoyl ring of 4-chlorobenzoyl-CoA. In both simulations, water molecules were able to diffuse into the active site of the enzymes. The trajectories provide insight into the routes that water may use to get into position for the hydrolysis portion of the dehalogenation reaction. In both simulations, the water molecule entering the active site forms a hydrogen bond with Asp-145.


Subject(s)
Bacterial Proteins/chemistry , Hydrolases/chemistry , Amino Acid Substitution , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Binding Sites , Codon/genetics , Hydrogen Bonding , Hydrolases/genetics , Hydrolases/metabolism , Models, Molecular , Mutation, Missense , Protein Conformation , Pseudomonas/enzymology , Stochastic Processes , Water/chemistry
SELECTION OF CITATIONS
SEARCH DETAIL
...