Biomedical subjects

M S Chen

Publications and source records attributed to M S Chen.

At least 37 records · Page 2Linked to original sources

PubMed2000

Epidemiologic study of type 2 diabetes in Taiwan.

Diabetes mellitus (DM) in adults is a global health problem, although its prevalence varies widely between different populations and the rate has generally increased worldwide. In Taiwan, the mortality rate from DM has almost doubled over the past 10 years. The prevalence of DM in Taiwan was established between 1985 and 1996 and the rates were between 4.9 and 9.2%. The prevalence of impaired glucose tolerance (IGT) was 15.5% (men 15% and women 15.9%). The prevalence of DM and IGT increased significantly with age for both genders. The significant factors associated with newly diagnosed DM were age, BMI, family history of DM, systolic blood pressure (hypertension), physical activity and serum triglyceride levels. The prevalence of large vessel disease (LVD) in DM and non-diabetic subjects were 20.0 and 12.9%, respectively. Among diabetics, 15.8% had ischemic heart disease (IHD), 1.7% leg vessel disease (leg VD), and 2.5% stroke. In non-diabetics, the prevalence of the aforementioned macroangiopathies were 11.5, 0.2 and 1.2%, respectively. The diabetics had a significantly higher prevalence of macrovascular disease than non-diabetic subjects. The most significantly associated with the LVD was serum cholesterol levels. Serum cholesterol and HbA1(c) were significantly associated with the development of IHD. Cigarette smoking and female gender were significantly associated with the leg VD. The prevalence of diabetic retinopathy (DR) was 35.0%. (background DR 30%, preproliferative DR 2.8% and proliferative DR 2.2%, respectively.) The prevalence of DR for previously and newly diagnosed diabetics were 45.2 and 28.3% (men 42.8 vs. 33.3% and women 47.5 vs. 24.8%), respectively. From multiple logistic regression analysis, duration of DM was the most important risk factor related to DR. Diabetic subjects treated with insulin had a higher risk of developing retinopathy than those treated with dietary control. The prevalence of nephropathy and neuropathy were 12.9 and 23.5%, respectively. For those patients with and those without nephropathy and neuropathy, the duration of DM, percentage of insulin treatment, percentage of hypertension, and fasting plasma glucose were significantly different. Diabetic duration, hypertension, insulin treatment and glycemic control consistently correlated with nephropathy and neuropathy. In conclusion, the prevalence of DM in Taiwan was between 4.9 and 9.2%, and the prevalence of IGT was 15.5%. The possible risk factors of newly diagnosed diabetes were age, family history of DM, BMI, SBP (hypertension), physical activity and triglyceride levels. Diabetes in Chinese subjects share many characteristics similar to other Asian populations. The burden imposed by the chronic complications of diabetes is massive. In Taiwan, the mortality rates from DM have increased greatly over the past 10 years. Reduction of the modificable risk factors such as BMI, hypertenion and dyslipidemia, and increase of physical activity and good glycemic control through public health efforts may help to reduce the risk of DM and its chronic complications.

Adult↗

PubMed2000

Tobacco use characteristics among rural Ohio Appalachians.

Appalachians remain at high risk for cancer, heart and lung disease, in part because of their high prevalence of tobacco use; yet, information about their tobacco consumption patterns is limited. The purpose of this study was to describe tobacco consumption variables among rural adult Appalachian tobacco users. Subjects, aged 18 and older (N = 249), participated in a face-to-face interview about tobacco consumption variables and knowledge regarding the health effects of tobacco at fairs in two rural Ohio Appalachian counties. The majority of participants were categorized as precontemplators, although 21 percent were classified in preparation stage of change. Mean age of initiation was 16.6 years and number of cigarettes smoked per day (cpd) was significantly higher for men, as compared to women. One-third of males reported the use of smokeless tobacco. The majority had not tried to quit for more than a year and the average number of previous quit attempts was low. One-half of the sample had been advised in the past to quit by their physician. Few had used nicotine replacement with past quit attempts but greater than half would consider this approach with future attempts. Knowledge about the health effects of smoking indicated that most were aware of the relationship between smoking and cancer but less than one-half recognized its association with heart disease. Those with less education were less informed about the health effects to self and non-smokers. While a sizeable portion expressed interest in quitting, knowledge about the health effects of smoking is lacking, especially with regard to heart disease and among those with less education.

Adolescent↗

PubMed2000

Cotinine levels in Southeast Asian smokers.

Understanding the contribution of race to factors associated with cigarette smoking and nicotine metabolism is essential for the characterization of patterns of tobacco use, nicotine dependence and incidence of tobacco-related diseases. This paper reports an investigation of cotinine levels among Southeast Asian smokers in two separate studies. Study 1 included 327 male and female smokers who participated in community-based interviews where smoking history information was obtained and a saliva continine sample was collected. Results indicated that subjects smoked an average of 11.2 cigarettes/day, with men reporting significantly higher consumption rates as compared to women (p < 0.0001). Subjects' mean cotinine level was 65 ng/ml with an average cotinine/cigarette ratio of 8.2. In Study 2, plasma and saliva cotinine in six Southeast Asian adult smokers were measured during 2 days of smoking followed by 6 days of abstinence. On day 1, mean plasma and saliva continine levels were 268 and 235 ng/ml, respectively. After 6 days of abstinence, mean levels had dropped to 12 ng/ml for plasma and 8 ng/ml in saliva. On average, it required at least 4.7 days for saliva continine levels to reach < 14 ng/ml. Mean cotinine concentrations during smoking differed in these two separate studies. Implications of these findings are discussed and future research recommendations are presented.

Adult↗

PubMed2000

Results of intraoperative mitomycin C application in dacryocystorhinostomy.

AIMS: To evaluate the long term results of intraoperative mitomycin C application in dacryocystorhinostomy (DCR) surgery compared with results of the conventional procedure. METHODS: In this prospective randomised controlled study, a total of 88 eyes diagnosed with acquired nasolacrimal duct obstruction were randomly divided into a conventional DCR group and a mitomycin C group in which mitomycin C was used during DCR surgery. The surgical procedures in both groups were exactly the same, except that in the patients in the mitomycin C group, a piece of neurosurgical cottonoid soaked with 0.2 mg/ml mitomycin C was applied to the osteotomy site for 30 minutes. The results of the DCR surgeries were evaluated by objective findings such as irrigation and the height of tear meniscus and subjective symptoms by asking patients the condition of tearing improvement. RESULTS: Among the 44 eyes in the mitomycin C group, 95.5% of patients remained totally symptom free after 10 months of follow up; while in the conventional group, 70.5% of patients were reported to be symptom free and 18% of patients to have an improvement in their symptoms. There was a significant difference between these two groups. As far as objective findings were concerned, there were 41 eyes in the mitomycin C group classified as having a normal and one eye with moderate tear meniscus level, compared with 32 eyes and seven eyes, respectively, in the conventional group. There was also a significant difference between these two groups. The non-patency rate in the mitomycin C group is 4.5% compared with 11.4% in the conventional group. There were no complications such as abnormal nasal bleeding, mucosal necrosis, or infection except one patient with delayed wound healing. CONCLUSIONS: Intraoperative mitomycin C application is effective in increasing the success rate of DCR surgery in standard nasolacrimal duct obstruction, and no significant complications resulted from its use.

Dacryocystorhinostomy↗

PubMed1999

Role of the integrin-associated protein CD9 in binding between sperm ADAM 2 and the egg integrin alpha6beta1: implications for murine fertilization.

CD9 is a tetraspan protein that associates with several beta1 integrins, including alpha6beta1. Because alpha6beta1 is present on murine eggs and interacts with the sperm-surface glycoprotein ADAM 2 (fertilin beta), we first asked whether CD9 is present on murine eggs and whether it functions in sperm-egg binding and fusion. CD9 is present on the plasma membrane of oocytes in the ovary as well as on eggs isolated from the oviduct. The anti-CD9 mAb, JF9, potently inhibits sperm-egg binding and fusion in vitro in a dose-dependent manner. JF9 also disrupts binding of fluorescent beads coated with native fertilin or a recombinant fertilin beta disintegrin domain. (Both ligands bind to the egg via alpha6beta1.) Immunohistochemistry showed that CD9 is undetectable in the uterine epithelium, appears basolaterally and as prominent apical patches on the epithelium in the region between the uterus and the oviduct, and then persists apically in the oviduct. The integrin alpha6A subunit is found in similar apical patches in the region between the uterus and oviduct, but is confined to the basal aspect of the epithelium in the uterus and oviduct. Hence, alpha6A and CD9 both are expressed on the apical epithelial surface at the uterine-oviduct junction. These findings correlate with the observation that fertilin beta "knockout" sperm traverse the uterus but do not progress into the oviduct, contributing to the infertility of fertilin beta(-/-) male mice. Our results suggest that high-avidity binding between fertilin beta (ADAM 2) and alpha6beta1 requires cooperation between alpha6beta1 and CD9. Such cooperation may assist sperm passage into the oviduct as well as sperm-egg interactions.

ADAM Proteins↗

PubMed1999

Hsc40, a new member of the hsp40 family, exhibits similar expression profile to that of hsc70 in mammalian cells.

Here, we report the identification and characterization of a new hsp40 family member, heat shock cognate 40 (hsc40), which may be a specific functional partner for hsc70. The hsc40 gene consists of five exons and four introns. The previously characterized hsp40 gene contains only three exons and two introns. Despite this difference in the numbers of exons and introns, the structures of these two genes are actually quite similar. If the first two exons and introns of the hsc40 gene are excluded, the rest is essentially the same as the whole hsp40 gene. The intron/exon boundaries of the hsc40 and hsp40 genes are conserved with respect to amino acid coding, indicating that the hsp40 gene might have arisen from a duplicated hsc40 gene, which developed a new transcription-regulatory mechanism in the second intron. Hsc40 is evolutionally conserved. There is over 95% sequence identity between the putative mouse and human hsc40 proteins. However, there is only 60% sequence identity between the hsc40 and hsp40 proteins from either human or mouse cells. Northern blot analysis of various tissues and cells in culture revealed that this gene was expressed under normal conditions, and its expression was further increased after various stress treatments. The expression pattern of the hsc40 gene is very similar to that of the hsc70 gene under both normal and stress conditions, whereas the hsp40 gene exhibited an expression pattern more similar to that of hsp70 genes on the same Northern blots. These results, considered along with the high rate of sequence conservation between the same proteins from different species and high rate of variation between the two different proteins from the same species, strongly suggest that hsc40 and hsp40 may perform different functions and/or have different specificities in the cell.

3T3 Cells↗

PubMed1999

Identification of conserved residues required for the binding of a tetratricopeptide repeat domain to heat shock protein 90.

The sequential binding of heat shock protein 90 (hsp90) to a series of tetratricopeptide repeat (TPR) proteins is critical to its function as a molecular chaperone. We have used site-directed mutagenesis to clarify the structural basis for the binding of hsp90 to the TPR domain of phosphoprotein phosphatase 5 (PP5). This TPR domain was chosen for study because its three-dimensional structure is known. We examined co-immunoprecipitation of hsp90 with wild type and mutant TPR constructs from transfected cells. Only mutations located on one face of the TPR domain affected hsp90 binding. This allowed the identification of a binding groove. Three basic residues that are highly conserved in hsp90-binding TPR proteins extend prominently into this groove. Lys-97 and Arg-101 were absolutely required for hsp90 binding, while mutation of Arg-74 diminished, but did not abrogate, hsp90 binding. Mutation of Lys-32, another conserved basic residue in the binding groove, also blocked hsp90 binding. The TPR domain of PP5 bound specifically to a 12-kDa C-terminal fragment of hsp90. This binding was reduced by mutation of acidic residues in the hsp90 fragment. These data suggest conservation, among hsp90-binding TPR proteins, of a binding groove containing basic residues that interact with acidic residues near the C terminus of hsp90.

Amino Acid Sequence↗

PubMed1999

Evidence that distinct states of the integrin alpha6beta1 interact with laminin and an ADAM.

Integrins can exist in different functional states with low or high binding capacity for particular ligands. We previously provided evidence that the integrin alpha6beta1, on mouse eggs and on alpha6-transfected cells, interacted with the disintegrin domain of the sperm surface protein ADAM 2 (fertilin beta). In the present study we tested the hypothesis that different states of alpha6beta1 interact with fertilin and laminin, an extracellular matrix ligand for alpha6beta1. Using alpha6-transfected cells we found that treatments (e.g., with phorbol myristate acetate or MnCl2) that increased adhesion to laminin inhibited sperm binding. Conversely, treatments that inhibited laminin adhesion increased sperm binding. Next, we compared the ability of fluorescent beads coated with either fertilin beta or with the laminin E8 fragment to bind to eggs. In Ca2+-containing media, fertilin beta beads bound to eggs via an interaction mediated by the disintegrin loop of fertilin beta and by the alpha6 integrin subunit. In Ca2+-containing media, laminin E8 beads did not bind to eggs. Treatment of eggs with phorbol myristate acetate or with the actin disrupting agent, latrunculin A, inhibited fertilin bead binding, but did not induce laminin E8 bead binding. Treatment of eggs with Mn2+ dramatically increased laminin E8 bead binding, and inhibited fertilin bead binding. Our results provide the first evidence that different states of an integrin (alpha6beta1) can interact with an extracellular matrix ligand (laminin) or a membrane-anchored cell surface ligand (ADAM 2).

ADAM Proteins↗

PubMed1999

Reduced crystallization inhibition by urine from men with nephrolithiasis.

BACKGROUND: Human urine is known to inhibit growth, aggregation, nucleation, and cell adhesion of calcium oxalate monohydrate (COM) crystals, the main solid phase of human kidney stones. This study tests the hypothesis that low levels of inhibition are present in men with calcium oxalate stones and could therefore promote stone production. METHODS: In 17 stone-forming men and 17 normal men that were matched in age to within five years, we studied the inhibition by dialyzed urine proteins of COM growth, aggregation, and binding to cultured BSC-1 renal cells, as well as whole urine upper limits of metastability (ULM) for COM and calcium phosphate (CaP) in relationship to the corresponding supersaturation (SS). RESULTS: Compared with normals, patient urine showed reduced COM growth inhibition and reduced ULM in relationship to SS. When individual defects were considered, 15 of the 17 patients were abnormal in one or more inhibition measurements. ULM and growth inhibition defects frequently coexisted. CONCLUSIONS: Reduced COM growth and CaP and CaOx ULM values in relationship to SS are a characteristic of male stone formers. Both defects could promote stones by facilitating crystal nucleation and growth. Abnormal inhibition may be a very important cause of human nephrolithiasis.

Calcium↗

PubMed1999

Informal care and the empowerment of minority communities: comparisons between the USA and the UK.

This paper examines informal care and the empowerment of minority communities with respect to health care and health promotion in the USA and the UK based upon work prepared for the workshop, 'Involving Black and Minority Ethnic Users in Delivery of Services and Empowering Communities' presented during the bi-national 1997 USA, UK. Conference, 'Health Gain for Black and Minority Ethnic Communities' and the information gained from that Conference. 'Informal care' is operationally defined as 'the practice of alleviating distressful physiological and psychological dysfunctions through all others (e.g. traditional healers, family members, self, etc.) using measures that do not require a physician's prescription or intervention (e.g. lifestyle modifications) typically outside of formal, institutionally based care mechanisms (e.g. homes and communities). Informal care is a significant force in health maintenance, health promotion, and disease prevention. In the USA, at least one-third of the population is estimated to engage in unconventional medical practices, and perhaps, one-half of racial/ethnic populations use informal care. An enormous potential exists to better utilize informal care because informal care is culturally more compatible, relatively low cost, and flexible. The policy of the Indian Health Service in accepting the use of traditional medicine was cited. The US Congress recognized the potential of alternative medicine by establishing such an Office within the National Institutes of Health. 'Empowerment of racial/ethnic minority communities is the right for minority populations to determine their own destinies. In the USA, racial/ethnic minority populations are Blacks, Hispanics, Asians or Pacific Islanders, and American Indian/Alaska Native. These classifications are based upon self-report; in the UK, the black and minority classifications are based upon countries of birth rather than self-reported racial/ethnic identities. Empowerment of these communities is important both demographically and historically. In demographic terms, racial/ethnic minority populations are increasing at higher rates than the majority population in the USA and hence, the health status of minorities will become the health status of the nation in the next half century. Historically, racial/ethnic minorities have not been empowered. As a consequence of the 1985 Secretary's Task Force Report on Black and Minority Health Federal measures to address disparities in the health status of minorities were initiated. In March 1994, the UK Government initiated the Ethnic Health Unit within the National Health Service. These measures are not mature enough to evaluate their impact. However, progress in implementing measures to empower minorities in the UK have begun and are illustrated by the work reported by Dr Pui-Ling Li, the UK counterpart to the workshop, 'Involving Black and Minority Ethnic Users in Delivery of Services and Empowering Communities'. Recommendations are made to increase use of informal care and the empowerment for racial/ethnic minority communities and to build upon the works in progress in both the USA and the UK.

Complementary Therapies↗

PubMed1999

Unique features of Chinese hamster S13 gene relative to its human and Xenopus analogs.

We have cloned and sequenced the ribosomal protein S13 gene from the Chinese hamster fibroblast HA-1 cells. The predicted protein encoded by this gene is identical to the human ribosomal protein S13, except for one amino acid substitution at residue 29, which is an alanine in the hamster protein and a threonine in that of humans. The physical organization of the six exons and five introns in the hamster S13 gene is also identical to that found in the human and Xenopus genes with respect to the amino acid codes, even though there are small differences in the lengths of the introns. The striking feature is that unlike its human and Xenopus counterparts, which encode two U14 snoRNAs in two separate introns, the hamster S13 gene encodes no U14 snoRNA. Instead, the hamster gene has a pseudo-U14 coding sequence in its third intron. Our data support the idea that the single copy of the hsc70/U14 gene, which we had previously characterized, is the only source for the production of both U14 snoRNA and hsc70 mRNA species in hamster HA-1 cells.

Amino Acid Sequence↗

PubMed1999

Assessing decisional balance for smoking cessation among Southeast Asian males in the US.

This study examines the relationship of positive and negative perceptions of smoking to self-reported readiness to quit smoking among Southeast (SE) Asian males of Cambodian, Laotian or Vietnamese descent. In order to investigate this relationship, measures of decisional balance constructs (i.e. the pros and cons of smoking) appropriate for these ethnic groups were developed. Decisional balance was calculated by subtracting the cons from the pros. Following the criteria established by Prochaska and DiClemente, subjects were categorized into four levels of readiness to quit smoking (precontemplation, contemplation, preparation/action and maintenance). The expected pattern of relationship between decisional balance and stages of change included: (1) the cons of smoking being of less importance than the pros of smoking for those smokers in the precontemplation stage, (2) the pros and cons intersecting at the contemplation stage, and (3) the cons being of greater importance than the pros in the later stages of change. The SE Asian men in this study did not exhibit these decisional balance patterns, although mean decisional balance scores for precontemplators and contemplators were significantly more positive than mean scores for those in the preparation/action and maintenance stages. Decisional balance patterns differed across the three ethnic groups included in the sample.

Adult↗

PubMed1999

China's "market economics in command": footwear workers' health in jeopardy.

This study of occupational safety and health (OSH) problems in the footwear industry in China, the world's largest shoemaker, is based on four years of research in China supplemented by research in Taiwan, Australia, and the United States. With the advent of the economic reforms of the early 1980s, the Chinese state is being driven by an economic imperative under which the profit motive overrides other concerns, causing a deterioration in OSH conditions. Footwear workers are being exposed to high levels of benzene, toluene, and other toxic solvents contained in the adhesives used in the shoe-making process. Many workers have been afflicted with aplastic anemia, leukemia, and other health problems. Most of China's current permissible exposure limits to toxins are either outdated or underenforced. As a result, the Chinese state's protection of footwear workers' health is inadequate. The article aims to draw the attention of the international OSH community to the importance of setting specific exposure standards for the footwear industry worldwide.

China↗

PubMed1999

Laser flare-cell meter analysis of blood-aqueous barrier functional status in a patient with crystalline retinopathy.

This is the first report in the literature of the application of a laser flare-cell meter to examine the functional status of the blood-aqueous barrier in a patient with crystalline retinopathy. The patient, a 34-year-old man with typical crystalline retinopathy, had crystal deposits scattered throughout the posterior pole of the fundus in both eyes. Fluorescein angiography showed atrophy of the retinal pigment epithelium and geographic areas of choriocapillaris atrophy in the posterior pole. Electroretinography showed subnormal amplitude, and the light-peak/dark-trough ratio of the electrooculogram was reduced. Laser photometry showed an increase in the aqueous flare intensity in both eyes, compared with normal values obtained from healthy control subjects. The increase in the aqueous flare intensity in this patient indicates that the function of the blood-aqueous barrier might have been affected in crystalline retinopathy.

Adult↗

PubMed1999

Evaluation of serum CA27.29, CA15-3 and CEA in patients with breast cancer.

The Truquant BR radioimmunoassay (RIA) using monoclonal antibody BR 27.29 to recognize a peptide sequence on the MUC-1 gene product for quantification of the CA 27.29 antigen in serum was used in this report to evaluate in 145 patients with breast cancer and compared the other conventional serum markers such as CA15-3 and CEA. The upper limit of normal (25 u/ml) was determined from CA27.29 values 12.4 +/- 4.1 u/ml (mean +/- 3 S.D.) for 112 female subjects apparently free of disease. The CA15-3 levels above 25 u/ml and CEA levels above 5 ng/ml were considered positive values. Thirty-seven cases of 145 patients studied had elevated CA 27.29 levels (sensitivity: 25.5%), 35 of 145 had positive CA15-3 levels (sensitivity 24.1%) and 27 of 145 patients had positive CEA levels (sensitivity: 18.6%) (p < 0.05). One hundred and ten cases of the breast cancer patients (75.8%) did not have metastatic disease. In this group CA 27.29 sensitivity was 6.4%, while CA15-3 sensitivity was 5.5% and CEA sensitivity was 4.5% (p > 0.05). Mean values were 10.2 +/- 9.2 u/ml for CA 27.29, 14.1 +/- 5.6 u/ml for CA 15-3 and 1.7 +/- 1.5 ng/ml for CEA. Thirty-five patients (24.2%) had metastatic disease. In this group CA 27.29 sensitivity was 85.7%, CA15-3 sensitivity was 82.8% and CEA sensitivity was 62.8% (p < 0.05). Mean values for CA27.29 was 152.6 +/- 131.6 u/ml, CA15-3 was 123.1 +/- 107.6 u/ml and 21.8 +/- 36.9 ng/ml of CEA. With regard to the correlation of three tumor markers with clinical stages, patients had significantly higher levels of CA27.29 than CEA, but they were similar to CA 15-3 in metastatic breast cancer. These results suggest CA27.29 to be more sensitive and specific than CEA, but that it is similar to CA15-3 for metastatic breast cancer detection and monitoring.

Adult↗

PubMed1999

[Determination of total sulfite in wine by high performance liquid chromatography(HPLC) with fluorescence detection].

A highly sensitive fluorometric method for the determination of total sulfite in wine is reported. The strong fluorescent derivatives formed by the quantitative reaction of sulfite in wine and N-(9-acridinyl) maleimide(NAM) in aqueous solution under mild conditions was injected into the HPLC. Separation was performed on an ODS column(200 mm x 5 mm) with a mobile phase of V(CH3CN):V(0.1 mo/L NH4AC) = 25:75 at a flow rate of 1.0 mL/min and detected by fluorometry at 455 nm(excitation at 365 nm). There was a good linear calibration curve in the range from 0.25-4 mg/L(r = 0.9998), The limit of detection was 1 ng. Sulfite mass concentration in wine has been determined by this method with good results and recoveries. This method is simple, rapid and reliable, and a sample size of only 1 mL is required to complete an analysis.

Chromatography, High Pressure Liquid↗

PubMed1998

Free radicals are involved in methylmethacrylate-induced neurotoxicity in human primary neocortical cell cultures.

Methylmethacrylate monomer (MMA), a highly volatile material, has been extensively used for the construction of complete or partial dental prostheses. While previous studies have indicated a variety of complications and untoward side-effects associated with its use, the possible neurotoxicity induced by this monomer has not been addressed. In this study, we have investigated the MMA-produced neuronal injury in human neuron-enriched primary culture. Embryonic brain tissue (8-10 weeks postconception) was used for the primary neuron-enriched culture. Phase-contrast microscopy was used to evaluate morphological changes of cultured neurons. Extracellular concentrations of lactate dehydrogenase (LDH) and nitrite was measured from the culture medium to assess the magnitude of neuronal damage and nitric oxide formation, respectively. Neocortical neurons exposed to the monomer (1/200, Vmonomer/Vglycerol) for two days resulted in a significant increase in the LDH level but monomer (1/20000, 1/2000, or 1/200; Vmonomer/Vglycerol) failed to increase the nitrite level. Morphologically, the neurons subjected to monomer treatment exhibited irregular shrunken cell bodies with dystrophic and/or fragmented neurities, or even cell lysis. Moreover, superoxide dismutase plus catalase or vitamin C pretreatment protected against monomer-induced neurotoxicity. Our results suggest that this neurotoxicity can not likely be attributed to the cytotoxic effects of nitric oxide but may be mediated through the toxicity of superoxide and other free radicals. This is the first time, to our knowledge, that neurotoxicity induced by MMA has been demonstrated in human cortical neurons.

Ascorbic Acid↗

PubMed1998

Video versus lecture: effective alternatives for orthodontic auxiliary training.

Many studies have compared the relative effectiveness of visually-aided lectures and videotapes, but methodological flaws have prevented definitive comparison of the techniques. This study assessed the relative effectiveness of the two approaches for orthodontic auxiliary training. This study was a prospective, randomised trial, conducted at the Eastman Dental Hospital and Institute. Two groups of 16 dental auxiliaries, selected at random, studied identification and positioning of orthodontic brackets: one group attended a lecture accompanied by slides and the other viewed a video. Subjects bonded brackets onto acrylic teeth and the results were assessed by computerised image analysis. The subjects completed a questionnaire on their attitudes to the respective teaching methods. Results were assessed for accuracy of bracket placement and variations in type of auxiliary. There was no significant difference between the teaching methods except for bracket positioning where video was slightly better (P < 0.05). There was no significant difference between the types of auxiliary. Generally, video teaching and lecturing were equally effective, with video achieving slightly better results. Both methods were effective at teaching bracket placement, and dental nurses and student hygienists proved equally adept at bracket positioning.

Attitude of Health Personnel↗