Biomedical subjects

A M Lee

Publications and source records attributed to A M Lee.

At least 19 recordsLinked to original sources

PubMed2005

A limited role for TP53 mutation in the transformation of follicular lymphoma to diffuse large B-cell lymphoma.

The role of TP53 mutation in transformation of follicular lymphoma (FL) to diffuse large B-cell lymphoma (t-FL) was examined in a panel of 91 lymph node biopsies derived from 29 patients pre- and post-transformation. The entire TP53 coding sequence was screened and immunocytochemistry performed to determine expression of p53 and its key regulator MDM2. A total of 10 mutations were detected in eight patients (28%), although none were present at FL diagnosis. Mutations were not detected solely at the time of transformation; in three patients, mutated TP53 arose in at least one antecedent FL sample (6 months, 2.5 years and 4 years prior to transformation). Loss of heterozygosity at the TP53 locus occurred in 2/20 informative patients (only in t-FL samples). p53 staining was positive in 82% (9/11) of available biopsies with a missense mutation, and negative in 71% (45/63) with wtTP53. MDM2 expression was significantly higher in t-FL samples (mean 72% positive; 95% confidence interval (95% CI) 68-76%) than FL (mean 58% positive; 95% CI 54-62%) (P<0.001) but did not correlate with TP53 status. TP53 mutation has only a limited role in the transformation of FL, exerting a heterogeneous influence upon phenotypic change. In contrast, dysregulation of MDM2 is frequent and may provide a more rational therapeutic target..

Cell Transformation, Neoplastic↗

PubMed2004

CD23 expression in mediastinal large B-cell lymphomas.

AIMS: Mediastinal large B-cell lymphoma (MLBCL) is a subtype of diffuse large B-cell lymphoma (DLBCL) in the WHO classification with peculiar features, such as female prevalence, young patient age and bulky presentation. It shows a B-cell phenotype with variable expression of surface immunoglobulin, negative CD21 and CD10 and positive CD30 in a large number of cases. An origin from activated thymic B cells has been suggested in several studies. A subpopulation of large, dendritic cells (asteroid cells) strongly expressing CD23 has been identified amongst thymic B cells and these could represent the normal cellular counterpart for this type of primary mediastinal large cell lymphoma. METHODS AND RESULTS: To explore this possibility, we immunostained 24 cases of primary mediastinal lymphomas and 100 cases of non-mediastinal, nodal and extranodal, DLBCLs for CD23 in routinely processed paraffin-embedded tissues. CONCLUSIONS: Our results show that a vast majority (70%) of mediastinal lymphomas strongly express CD23 whilst the same antigen is expressed in only 15% of non-mediastinal nodal DLBCLs and 9% of non-mediastinal extranodal DLBCLs. These results support the hypothesis that most cases of MLBCL arise from activated dendritic thymic B cells. We also suggest that CD23 should be included in the panel of antibodies currently used to characterize this subtype of DLBCL.

Adolescent↗

PubMed2003

Diversity of bacterial populations on the tongue dorsa of patients with halitosis and healthy patients.

The primary purpose of the present study was to compare the microbial profiles of the tongue dorsa of healthy subjects and subjects with halitosis by using culture-independent molecular methods. Our overall goal was to determine the bacterial diversity on the surface of the tongue dorsum as part of our ongoing efforts to identify all cultivable and not-yet-cultivated species of the oral cavity. Tongue dorsum scrapings were analyzed from healthy subjects with no complaints of halitosis and subjects with halitosis, defined as an organoleptic score of 2 or more and volatile sulfur compound levels greater than 200 ppb. 16S rRNA genes from DNA isolated from tongue dorsum scrapings were amplified by PCR with universally conserved bacterial primers and cloned into Escherichia coli. Typically, 50 to 100 clones were analyzed from each subject. Fifty-one strains isolated from the tongue dorsa of healthy subjects were also analyzed. Partial sequences of approximately 500 bases of cloned inserts from the 16S rRNA genes of isolates were compared with sequences of known species or phylotypes to determine species identity or closest relatives. Nearly complete sequences of about 1,500 bases were obtained for potentially novel species or phylotypes. In an analysis of approximately 750 clones, 92 different bacterial species were identified. About half of the clones were identified as phylotypes, of which 29 were novel to the tongue microbiota. Fifty-one of the 92 species or phylotypes were detected in more than one subject. Those species most associated with healthy subjects were Streptococcus salivarius, Rothia mucilaginosa, and an uncharacterized species of Eubacterium (strain FTB41). Streptococcus salivarius was the predominant species in healthy subjects, as it represented 12 to 40% of the total clones analyzed from each healthy subject. Overall, the predominant microbiota on the tongue dorsa of healthy subjects was different from that on the tongue dorsa of subjects with halitosis. Those species most associated with halitosis were Atopobium parvulum, a phylotype (clone BS095) of Dialister, Eubacterium sulci, a phylotype (clone DR034) of the uncultivated phylum TM7, Solobacterium moorei, and a phylotype (clone BW009) of STREPTOCOCCUS: On the basis of our ongoing efforts to obtain full 16S rRNA sequences for all cultivable and not-yet-cultivated species that colonize the oral cavity, there are now over 600 species.

Adult↗

PubMed2002

Risk factors for hepatotoxicity associated with rifampin and pyrazinamide for the treatment of latent tuberculosis infection: experience from three public health tuberculosis clinics.

SETTING: Three municipal tuberculosis (TB) clinics. OBJECTIVES: Reports of liver injury in patients treated with a 2-month regimen of daily rifampin and pyrazinamide (2RZ) for latent TB infection have raised concern about its safety. We aimed to evaluate the safety and tolerability of 2RZ and identify risk factors for hepatotoxicity. METHODS: We reviewed charts of adults started on 2RZ between 1999 and 2001. Cases with grade 3 hepatotoxicity (AST or ALT >5.0-20.0 x upper limit of normal) and grade 4 hepatotoxicity (AST or ALT >20.0 x upper limit of normal) were identified. RESULTS: Of 148 patients prescribed 2RZ, 85 (57.4%) completed therapy. Grade 3 or 4 hepatotoxicity occurred in 14 patients (eight grade 4 cases). In multivariate analysis, hepatotoxicity was associated with female sex (odds ratio [OR] 4.1; 95% confidence interval [CI] 1.2-14.3) and with presumed recent infection (recent tuberculin skin test conversion or contact with a TB case) (OR 14.3; 95%CI 1.8-115), but not with alcohol use, illicit drug use, age, race, or pyrazinamide dose. CONCLUSIONS: Hepatotoxicity occurred in a high proportion of patients prescribed 2RZ, and was more common among females and those with recent infection. Caution is warranted in using 2RZ in populations where its safety has not been established.

Adolescent↗

PubMed2001

Design and evaluation of a tryptophanless RecA protein with wild type activity.

The C-terminal domain of the Escherichia coli RecA protein contains two tryptophan residues whose native fluorescence emission provides an interfering background signal when other fluorophores such as 1,N(6)-ethenoadenine, 2-aminopurine and other tryptophan residues are used to probe the protein's activities. Replacement of the wild type tryptophans with nonfluorescent residues is not trivial because one tryptophan is highly conserved and the C-terminal domain functions in both DNA binding as well as interfilament protein-protein contact. We undertook the task of creating a tryptophanless RecA protein with WT RecA activity by selecting suitable amino acid replacements for Trp290 and Trp308. Mutant proteins were screened in vivo using assays of SOS induction and cell survival following UV irradiation. Based on its activity in these assays, the W290H-W308F W-less RecA was purified for in vitro characterization and functioned like WT RecA in DNA-dependent ATPase and DNA strand exchange assays. Spectrofluorometry indicates that the W290H-W308F RecA protein generates no significant emission when excited with 295-nm light. Based on its ability to function as wild type protein in vivo and in vitro, this dark RecA protein will be useful for future fluorescence experiments.

2-Aminopurine↗

PubMed2001

Rationales for Food Refusal in Chinese Patients with Anorexia Nervosa.

OBJECTIVE: To study the rationales for food refusal among Chinese patients with typical and atypical anorexia nervosa. METHOD: Forty-eight consecutive patients with broadly defined anorexia nervosa underwent evaluation with a self-report rationale for food refusal questionnaire, the 12-item General Health Questionnaire (GHQ-12), the 21-item Beck Depression Inventory (BDI-21), the Hamilton Depression Rating Scale (HDRS), and other clinical assessments. RESULTS: Fat-phobic patients (N = 32) had a significantly higher premorbid body mass index than non-fat-phobic patients (N = 16), but they did not differ on other clinical parameters, GHQ-12, BDI-21, and HDRS scores. At clinical presentation, 3 months, and 1 year prior to presentation, fat phobia and stomach bloating were the most common rationales for food refusal among fat-phobic and non-fat-phobic patients, respectively. A total of 31% of fat-phobic patients endorsed non-fat-phobic rationales at the time of clinical presentation, whereas non-fat-phobic patients adhered to non-fat-phobic attributions more consistently. DISCUSSION: The rationales used by anorexic patients to explain noneating are more varied than implied in the 4th ed. of the Diagnostic and Statistical Manual of Mental Disorders and the ICD-10 Classification of Mental and Behavior Disorders: Clinical Descriptions and Diagnostic Guidelines. A broadened conceptualization of anorexia nervosa may enhance an understanding of patients' illness experiences and enliven research on eating disorders.

Adult↗

PubMed2001

Working with licensed cosmetologists to promote health: results from the North Carolina BEAUTY and Health Pilot Study.

BACKGROUND: Beauty salons are located in all communities and represent a promising channel for delivering health promotion programs. No previous salon-based health promotion program has assessed the needs, interests, and preferences of licensed cosmetologists about sharing health information with their clients. METHODS: Licensed cosmetologists in one town completed a mailed survey assessing (1) health topics typically discussed with clients, (2) interest in delivering messages about beauty and health, and (3) preferred methods for learning about and sharing health information with their clients. RESULTS: The average cosmetologist sees 47 clients per week and spends 30-60 min per appointment. Eighty-two percent report that they are interested in talking about health with their clients. Most cosmetologists already discuss a wide range of health topics with their clients and are most comfortable discussing healthy eating (65.3%), physical activity (63.3%), and dieting (63.3%). Cosmetologists preferred reading pamphlets (55.1%) and watching educational videos (46.9%) to learn about beauty and health. Distributing pamphlets (69.4%), talking with clients (61.2%), and placing posters/mirror stickers in the salons (59.2%) were the methods cosmetologists most preferred for sharing health information with their clients. CONCLUSIONS: Licensed cosmetologists are in a unique position to serve as "natural helpers" by delivering health messages to their clients and reinforcing those messages over time. Partnerships with licensed cosmetologists should be developed to deliver salon-based health promotion programs.

Adult↗

PubMed2001

Carotid endarterectomy in patients 55 years of age and younger.

Prior studies have suggested that young patients may be more prone to recurrent disease after carotid endarterectomy (CEA). The goal of this study was to review a series of CEAs performed on younger patients (< or = 55 years) and to determine if these patients are more likely to develop recurrent stenosis. A review was conducted of CEAs performed from 1985 through 1994. Analysis was performed on a study group of 94 young patients who underwent 109 CEAs during this time. A control group of 222 patients older than 55 years who underwent 256 CEAs during the years 1991 through 1993 was selected for comparison. During a mean of nearly 4 years of follow-up, younger patients were significantly more likely to experience a late failure of CEA, including total occlusion of the operated artery, or recurrent stenosis requiring redo surgery. Careful patient evaluation is important in choosing younger patients who require CEA. Implications of these data include mandating careful noninvasive follow-up examinations for younger patients undergoing CEA.

Adult↗

PubMed2001

Long-term follow-up of saphenous vein, internal jugular vein, and knitted Dacron patches for carotid artery endarterectomy.

To determine whether choice of material used for patch closure following carotid artery endarterectomy (CAE) influences rates of early or late restenosis, stroke, and death, 274 consecutive CAEs were retrospectively reviewed. Saphenous vein (SV) was used in 159 (58.0%) procedures; everted, double-thickness jugular vein (JV) was used in 25 (9.1%); and knitted Dacron (KD) was used in 90 (32.9%). Primary closure was not used in this series. There were four perioperative strokes: two (1.3%) in SV, one (4%) in JV, and one (1.1%) in KD (NS). Follow-up was obtained on 263 (96%) operated arteries (mean 41.5 months). Duplex scan results were available for 236 (89.7%) of these arteries (mean follow-up time 33.7 months). There were three (2%) late strokes in SV and two (2.2%) in KD (NS). In long-term follow-up, one patient (0.7%) in SV and two (2.4%) in KD developed > 80% stenosis (NS). One patient (0.7%) in SV, one (5.3%) in JV, and one (1.2%) in KD had total occlusion of the operated vessel (NS). Three procedures (2.2%) in SV, 1 (5.3%) in JV, and 7 (8.5%) in KD demonstrated moderate stenosis (50-79%) (NS). Three-year follow-up shows that choice of patch material does not affect early or late stroke rate, stroke-related death rate, rate of high-grade (> 80%) restenosis, or rate of total occlusion. There is a higher incidence of moderate stenosis in KD. Although our results and a review of the literature do not indicate that these patients are at increased risk for symptoms or progression of stenosis, they should be followed by duplex scanning to ensure that this is the case.

Aged↗

PubMed2001

Selective muscarinic receptor antagonists for airway diseases.

Airway tone and airway hyperreactivity are mediated by the parasympathetic nerves that release acetylcholine onto muscarinic receptors (M1-M5). Stimulation of M1 and M3 muscarinic receptors causes bronchoconstriction. The M1 muscarinic receptor is excitatory, and facilitates neuronal transmission at the parasympathetic ganglion. The M2 receptor is an inhibitory prejunctional autoreceptor. The discovery of discrete muscarinic receptor subtypes prompted development of selective muscarinic receptor antagonists. Selective M3 receptor antagonists and antagonists selective for M1 and M3 receptors have recently entered clinical trials and offer much promise for the treatment of airways diseases.

Animals↗

PubMed2001

The effects of augmented feedback on students' perceptions and performance.

The effects of augmented feedback on perceptions of ability (SPA), practice behaviors, and performance during motor skill instruction of a novel task were investigated. Fourth-grade students (N = 103) were randomly assigned to one of four conditions: (a) no feedback; (b) motivational feedback; (c) task feedback; or (d) motivation and task feedback. They then practiced simple and complex cupstacking skills. On a relatively simple task, the type of feedback did not have a significant effect on children's SPA, practice behaviors, or performance; but on a more complex task, differential effects of feedback were evident. Results indicate that informational feedback is an important factor in facilitating student engagement, fostering positive perceptions of ability, and ultimately improving performance on a challenging task.

Analysis of Variance↗

PubMed2001

Gender-related psychosocial and cultural factors associated with condom use among Chinese married women.

The present study explored the interplay of psychosocial, gender, and cultural factors on Chinese married women's condom use. A total of 433 Chinese married women residing in Hong Kong participated in the study. Correlation results showed that participants' conservative gender attitudes toward sexuality and sexual decision making were related to less accurate HIV/AIDS knowledge and less concern about contacting the disease from their husbands. About 34.4% of the sexually active participants never used condoms in the past 6 months, and current condom use was associated with egalitarian gender attitudes, positive feelings about condom use, and concerns about contacting HIV/AIDS from their husbands. Among all participants, 32.5% reported that they would not use condoms in their future sexual encounters. Future condom use was related to shorter duration of marriage, accurate HIV/AIDS knowledge, egalitarian gender attitudes, current condom use, and positive feelings about condom use. Results from the logistic regression analyses showed that egalitarian gender attitudes toward sexuality and positive feelings about condom use were the most salient predictors for current and future condom use.

Adult↗

PubMed2001

Effectiveness of denuding the intestinal mucosa by submucosal injection in the porcine model.

PURPOSE: Lack of mucosal regrowth on denuded bowel segments is considered a prerequisite for successful grafting of cultured urothelial cells for bladder augmentation. This study was designed to establish a technique for clean and complete de-epithelialization of the intestinal mucosa. MATERIALS AND METHODS: A segment of the small bowel was isolated in six microminipigs. The isolated segment was detubularized and the submucosa injected with HEPES-buffered saline, elevating the mucosa from the underlying tissue and allowing removal with ease. One portion was resected and, along with a portion of the removed mucosa and a sample of the full-thickness bowel, submitted for histologic evaluation. Another portion of the bowel segment remained denuded while the final denuded segment was covered with polyglactin mesh. After 3 days, 1 week, and 3 weeks, specimens from each of the bowel segments were collected for histologic assessment. Immunoperoxidase labeling was performed to confirm the presence or absence of mucosal regrowth. RESULTS: All intestinal segments showed no mucosal regrowth at the 3-day, 1-week, and 3-week incubation periods. Minimal reaction between the denuded bowel segment and the mesh was evident in all of the pigs. CONCLUSIONS: In the porcine model, intestinal mucosa can be removed completely using submucosal injection. This technique may be useful in future clinical studies involving bladder augmentation using denuded bowel.

Animals↗

PubMed2000

Disordered eating in three communities of China: a comparative study of female high school students in hong kong, Shenzhen, and rural hunan.

OBJECTIVE: To examine disordered eating and its psychological correlates among female high school students in three Chinese communities that lay on a gradient of socioeconomic development in China. METHOD: 796 Chinese students from Hong Kong, Shenzhen, and rural Hunan completed a demographic and weight data sheet, the Eating Attitudes Test (EAT-26), a Body Dissatisfaction Scale (BDS), the Beck Depression Inventory (BDI), and the Rosenberg Self-Esteem Scale (RSES). RESULTS: Compared to students in Hunan and to a lesser extent students in Shenzhen, students from Hong Kong were slimmer, but desired a lower body mass index (BMI), reported more body dissatisfaction, exhibited a more typical EAT-26 factor structure, scored higher on the "fat concern and dieting" factor, and constituted more EAT-26 high scorers. Multiple regression analyses indicated that BDS was the most significant predictor of fat concern at each site, but this effect was strongest in Hong Kong. Hunan students had significantly higher BDI scores but lower fat concern than Shenzhen and Hong Kong students. DISCUSSION: The consistent gradient of fat concern across the three communities gives credence to the view that societal modernization fosters disordered eating in women, possibly via the gendered social constraints that accompany it. It is also expressive of the marked socioeconomic heterogeneity within China nowadays. The predictable rising rate of eating disorders that follows global change will pose a growing public health challenge to Asian countries.

Adolescent↗

PubMed2000

The variability of phenomenology in anorexia nervosa.

OBJECTIVE: To study the variability of phenomenology in Chinese patients with anorexia nervosa in Hong Kong. METHOD: Longitudinal case studies of four patients. RESULTS: The anorexic illness was not uniformly about the fear of fatness. Rather, patients' explanations for food refusal could change over time. A typology of anorexic phenomenology emerged; namely, fat phobic type I (fat phobia consistently present), fat phobic type II (fat phobia changing to non-fat phobic presentation), non-fat phobic type I (consistently non-fat phobic) and non-fat phobic type II (non-fat phobic initially, but fat phobic later). CONCLUSION: The variability of anorexic phenomenology challenges the current fat phobia paradigm and has implications on the diagnosis, treatment and psychometric assessment of eating disorders.

Adolescent↗

PubMed2000

Psychiatric morbidity and illness experience of primary care patients with chronic fatigue in Hong Kong.

OBJECTIVE: The authors' goal was to examine the prevalence and experience of psychiatric morbidity among primary care patients with chronic fatigue in Hong Kong. METHOD: One hundred adult patients with medically unexplained fatigue for 6 or more months were assessed with the Explanatory Model Interview Catalogue, psychopathological rating scales, and an enhanced version of the Structured Clinical Interview for DSM-III-R. RESULTS: The lifetime prevalence of DSM-III-R depressive and anxiety disorders was 54%. Current depressive and anxiety disorders were identified in 28 patients, who exhibited more psychopathology and functional impairment than other patients. Thirty-three patients had somatoform pain disorder, and 30 had undifferentiated somatoform disorder, but most of them could also be diagnosed as having shenjing shuairuo (weakness of nerves) and, to a lesser extent, ICD-10 neurasthenia. Chronic fatigue syndrome diagnosed according to the 1988 Centers for Disease Control criteria was rare (3%) and atypical. Generally, patients mentioned fatigue if asked, but pains (36%), insomnia (20%), and worries (13%) were the most troublesome symptoms. Most patients attributed illness onset to psychosocial sources. CONCLUSIONS: Psychiatric morbidity was common among primary care patients with chronic fatigue. Subthreshold psychiatric morbidity was very common and was more validly represented by the disease construct of shenjing shuairuo or neurasthenia than somatoform disorder.

Adolescent↗

PubMed2000

[Tyrosine kinase expression in the inner ear of mice].

Tyrosine-specific phosphorylation events serve to modulate cell to cell interactions during the normal growth and development of many vertebrate tissues. Numerous studies have been performed on the involvement of growth factor receptor tyrosine kinases (RTKs) in inner ear function. Many RTKs, however, have only been recently identified, and their expression patterns have not yet been systematically examined in all tissues. In this study, we surveyed mouse inner ear transcript sequences for the presence of RTKs using a degenerate-PCR based methodology. Isolates encoding RTKs that had and had not been previously identified in the inner ear were obtained. Our data reveals the presence of numerous RTKs in the inner ear that have not yet been studied in the context of inner ear and demonstrates the usefulness of RT-PCR analysis in identifying genes involved in inner ear function.

Animals↗

PubMed2000

Ethanol reinforcement in nondeprived mice: effects of abstinence and naltrexone.

BACKGROUND: Operant experiments which indicate that ethanol can serve as a reinforcer to maintain lever responding during limited periods of access have not been conducted on non-food-deprived mice, as they have for rats and monkeys. Furthermore, there are no reports of the effects of chronic ethanol and subsequent abstinence on ethanol reward in mice. Finally, although naltrexone reduces responding for ethanol in food-deprived mice, the effects of the drug on ethanol reward for non-food-deprived mice have not been reported. METHODS: In three experiments, lever responding for ethanol (10-12%) was established in C57BL/6 (B6) mice by using either sucrose or saccharin fading procedures commonly used for rats. Experiment 1 examined both appetitive and consummatory responses while sucrose was faded from the ethanol solutions. Experiment 2 examined lever responding and ethanol intake (1) during saccharin fading; (2) when reinforcement schedules, reward availability, and primary conditioned reinforcers were manipulated; and (3) when mice were allowed chronic ethanol consumption followed by forced abstinence. Experiment 3 examined the effects of low doses of naltrexone on ethanol reward. RESULTS: Lever responding for ethanol can be established in non-food-deprived mice with the sucrose and saccharin fading procedures commonly used for rats. Lever responses increased with decreases in the reinforcer and increases in schedule demand, which indicated the reward value of the ethanol solution. Removal of ethanol from the solution reduced consumption with no change in the appetitive, instrumental response, which indicated that the two responses were under control of different stimuli, perhaps mediated by different neural mechanisms. Forced abstinence after chronic ethanol exposure increased responding for the drug, which suggested increased reward value. Naltrexone reduced responding as previously reported for food-deprived B6 mice. CONCLUSIONS: Ethanol appears to serve as a reinforcer for non-food-deprived or non-water-deprived B6 mice. Its reinforcing effects are increased by forced abstinence after chronic exposure and are decreased by naltrexone.

Animals↗