Biomedical subjects

G Ma

Publications and source records attributed to G Ma.

At least 19 recordsLinked to original sources

PubMed2003

Relative influence of diet and physical activity on cardiovascular risk factors in urban Chinese adults.

OBJECTIVE: The relative influence of dietary factors vs physical activity on cardiovascular risk factors are poorly understood. We investigated these factors in a population whose traditional diet may have both positive (high plant-based) and negative (high refined carbohydrate) aspects, and whose physical activity levels (PALs) vary widely. DESIGN: Cross-sectional study. SUBJECTS: A total of 130 weight stable adults aged 35-49 y (BMI 18-35 kg/m(2)) living in urban Beijing, China. MEASUREMENTS: Dietary intake (by food frequency questionnaire), PAL as the ratio of predicted total to resting energy expenditure), percent body fat (by deuterium oxide dilution), and central adiposity (waist circumference and waist to hip ratio) were assessed. Biochemical parameters (total cholesterol, low- and high-density lipoprotein cholesterol (LDL-C; HDL-C), triglyceride (TG), apolipoproteins A-I and B, glucose, insulin, and homocysteine and its related vitamins), blood pressure and presence of the metabolic syndrome (having >/=3 risk factors of central adiposity, HDL-C, TG, glucose, blood pressure) were also examined. RESULTS: Mean values for cardiovascular risk factors were relatively low, but 19% of subjects had the metabolic syndrome. Using validated methods for measuring food intake and energy expenditure, we found that an adverse cardiovascular risk profile was associated with a diet high in carbohydrate, low in polyunsaturated fat, and low in fruit and vegetables, independent of body fatness and its distribution. While dietary factors predicted individual cardiovascular risk factors more consistently than PAL, avoidance of low PAL reduced the risk of having the metabolic syndrome. CONCLUSION: These results suggest that, regardless of total body fatness and fat distribution, multiple unfavorable dietary factors and low physical activity independently increase the risk for cardiovascular disease. Avoidance of a sedentary lifestyle additionally reduces the risk of developing the metabolic syndrome.

Adult↗

PubMed2002

Energy requirements of urban Chinese adults with manual or sedentary occupations, determined using the doubly labeled water method.

OBJECTIVE: To examine total energy expenditure (TEE) in relation to occupation and reported leisure time activities in free-living Chinese adults, and to determine whether measured TEE values differ from current international dietary energy recommendations. SETTING AND SUBJECTS: Seventy three weight-maintaining adults aged 35-49 y, leading unrestricted lives in urban Beijing, with a wide variety of occupations. DESIGN AND METHODS: A cross-sectional study in which TEE was determined by doubly labeled water, body composition by deuterium oxide ((2)H(2)O) dilution, resting energy expenditure (pREE) by prediction equations, and occupational and leisure time activities by questionnaire. RESULTS: For men and women respectively, TEE averaged 12.10+/-0.32 and 9.53+/-0.23 MJ/day (P<0.001), and physical activity level (PAL=TEE/pREE) was 1.77+/-0.04 and 1.66+/-0.02 (P<0.05). Fat-free mass (FFM) was the single best predictor of TEE (adjusted r(2)=0.71, P<0.001). Occupational category (light, moderate and heavy) further predicted TEE, independent of FFM (adjusted multiple r(2)=0.82, P<0.001). Both TEE adjusted for weight and PAL increased with occupational category. Measured TEE was slightly but significantly higher than the 1985 FAO/WHO/UNU estimates for women with light occupations, but did not differ from estimates for men with light occupations, or for adults with moderate or heavy occupations. CONCLUSION: Level of occupational activity, but not duration or type of leisure activity, significantly predicted TEE in free-living urban Chinese adults. Current energy requirement recommendations slightly underestimated the energy needs of women with light occupations but were accurate for men and women with moderate and heavy occupations. SPONSORSHIP: NIH grants DK53404 and F32-DK09747.

Adult↗

PubMed2002

Sequence analysis and expression of a virus-like particle protein, VLP2, from the parasitic wasp Venturia canescens.

Endoparasitoid wasps produce maternal protein secretions, which are transported into the body of insect hosts at oviposition to regulate host physiology for successful development of their offspring. Venturia canescens calyx fluid contains so-called virus-like particles (VLPs) that are essential for immune evasion of the developing parasitoid inside the host. VLPs consist of four major proteins. In this paper, we describe the isolation and molecular cloning of a gene (vlp2) that is a constituent of VLPs and discuss its possible role in VLP structure and function.

Amino Acid Sequence↗

PubMed2001

Structure of the dimethyl sulfoxide solvated thallium(III) ion in solution and in the solid state.

The structure and vibrational spectra of the dimethyl sulfoxide solvated thallium(III) ion have been studied in a dimethyl sulfoxide solution and in the solid state. X-ray crystallography shows a trigonal unit cell, space group R(-)3 (No. 148), for the [Tl(dmso)(6)](ClO(4))(3) compound with Z = 3, a = b = 11.9764(13) [11.8995(9)] A, c = 20.802(2) [20.467(2)] A, and V = 2584.0(5) [2509.9(4)] A(3) at 295 [150] K. The crystal structure comprises a highly symmetric hexakis(dimethyl sulfoxide)thallium(III) ion, with thallium in a (-)3 symmetry site and a Tl-O bond distance of 2.224(3) A at 295 K. The octahedral TlO(6) kernel is compressed along the threefold axis with an O-Tl-O bond angle of 96.20(11) degrees. The Tl-O-S bond angle of 120.7(2) degrees corresponds to a Tl.S distance of 3.292(2) A. One perchlorate ion centered on the (-)3 axis was described by a statistically disordered model. A low-temperature EXAFS study (10 K) resulted in the Tl-O and Tl.S distances of 2.221(4) and 3.282(6) A, respectively, consistent with a Tl-O-S bond angle of 120(1) degrees. The low Debye-Waller factors confirm a regular coordination without the disorder of the dimethyl sulfoxide ligands, which would have resulted from the alternative choice of space group R3 for the crystal structure. Raman and infrared spectra have been recorded and assigned, with the bands at 435 and 447 cm(-)(1) corresponding to the vibrational frequency of the symmetric and asymmetric Tl-O stretching modes, respectively. EXAFS data of a 0.5 mol dm(-3)thallium(III) trifluoromethanesulfonate in a dimethyl sulfoxide solution were consistent with that of a hexasolvated ion with mean Tl-O and Tl.S distances of 2.22(1) and 3.33(2) A, respectively, which correspond to a mean Tl-O-S bond angle of 124(2) degrees. The anomalously large disorder parameter for the Tl-O distances is consistent with a weak pseudo-Jahn-Teller effect. The (205)Tl, (13)C, and (1)H NMR spectra of the complex in solution show single signals at 1886, 39.5, and 2.3 ppm, respectively.

Cations↗

PubMed2001

Electrocardiographic manifestations: digitalis toxicity.

Toxicity from the digitalis family of cardiac glycoside medications remains common. Successful treatment depends on early recognition; however, the diagnosis of potentially life-threatening toxicity remains difficult because the clinical presentation is often nonspecific and subtle. The hallmark of cardiac toxicity is increased automaticity coupled with concomitant conduction delay. Though no single dysrhythmia is always present, certain aberrations such as frequent premature ventricular beats, bradydysrhythmias, paroxysmal atrial tachycardia with block, junctional tachycardia, and bidirectional ventricular tachycardia are common. Treatment depends on the clinical condition rather than serum drug level. Management varies from temporary withdrawal of the medication to administration of digoxin-specific Fab fragments for life-threatening cardiovascular compromise.

Aged↗

PubMed2001

Elevated potassium intake inhibits neointimal proliferation in the swine coronary artery.

BACKGROUND: Previously, we reported that elevated extracellular potassium concentration in vitro inhibited proliferation and migration of vascular smooth muscle cells, formation of free radical compounds by macrophages, and reduced platelet sensitivity to agonists. More recently, we described a reduction in neointimal proliferation after balloon angioplasty injury in the carotid arteries of rats associated with an elevation of dietary potassium intake during a 4-week experiment. In the present study we conducted a similar investigation in the swine coronary artery balloon angioplasty model. PROCEDURES: Two groups of seven castrated male swine were studied; for 28 days the normal potassium group consumed a diet containing 0.25% potassium and the high potassium group ate diet containing 2.0% potassium. After 14 days on the diet, balloon angioplasty was performed. After an additional 14 days on the same diets the hearts were removed, and normal and lesioned sections of the artery were analyzed histologically. RESULTS: The neointimal area was markedly less in the high potassium group than in the normal potassium group, 0.33+/-0.04 mm2 v 0.74+/-0.10 mm2 (P < .004). Neointimal area-to-total wall area ratio in the normal potassium group averaged 0.199+/-0.018, significantly greater than the ratio computed for the elevated potassium group, 0.120+/-0.015 (P < .006). CONCLUSION: These results support the hypothesis that a high level of dietary potassium intake inhibits neointimal proliferation after balloon angioplasty in the swine coronary artery.

Aldosterone↗

PubMed2001

Polymorphisms of the CYP1A1 and GSTM1 genes in relation to individual susceptibility to lung carcinoma in Chinese population.

Cytochrome P450 1A1 (CYP1A1) and glutathione S-transferase M1 (GSTM1) metabolize tobacco-related carcinogens. To investigate the prevalence of CYP1A1 and GSTM1, and their association with increased risk of lung carcinoma in Chinese, allele-specific PCR and multiplex PCR technique were employed to identify the genotypes of CYP1A1 and GSTM1 in a case-control study of 106 lung carcinoma patients with histopathological diagnosis and 106 matched controls free of malignancy in Jiangsu Province, China. Logistic regression analysis was performed to calculate the odds ratio (OR) and 95% confidence intervals (CI). The results showed that individuals with GSTM1 null, and the combined GSTM1 null/CYP1A1 Ile/Val or GSTM1 null/CYP1A1 Val/Val had an elevated risk of lung carcinoma, with the OR, 1.92 (P=0.02; CI, 1.07-3.46), 3.27 (P=0.01; CI, 1.23-8.84) and 9.33 (P=0.04; CI, 1.01-217.42), respectively. Light smokers (<30 pack-years) carrying GSTM1 null genotype were shown to have the increased risk to lung carcinoma (OR=3.47; CI, 1.13-7.57). Our study suggested that the null GSTM1 genotype, independently or in combined with at least one Val allele of CYP1A1, might affect the genetic susceptibility for lung carcinoma in Chinese population.

Adult↗

PubMed2001

Re-emergence of iodine deficiency in Australia.

Iodine is an essential nutrient for human growth and development. The thyroid gland is dependent upon iodine for production of thyroid hormone. It is a common perception that iodine deficiency is not a major public health concern in mainland Australia, with sporadic studies carried out about a decade ago showing average urinary iodine excretion levels of around 200 microg/day. Recent evidence, however, has shown that the consumption of iodine is declining in Australia. A similar situation has occurred in the USA. The present study was designed to evaluate the urinary iodine excretion (UIE), as the indicator of iodine nutrition, in samples obtained from various demographic groups in the Sydney metropolitian area, namely: schoolchildren, healthy adult volunteers. pregnant women and patients with diabetes. Urinary iodine in spot urine sample was measured in a Technicon II autoanalyser using an in-house, semiautomated method. The results in this communication show that all four study groups had the median UIE below 100 microg/L. the criteria set by the World Health Organization for iodine repletion, and confirm what has been described previously, that iodine deficiency has reemerged in Sydney, Australia. One of the major causes of the reduced iodine intake is the reduction of iodine in milk since the dairy industry replaced iodine-rich cleaning solutions with other sanitisers. Secondly, less than 10% of the population are currently using iodised salt. A national survey into the iodine nutrition status in Australia is urgently required as part of the establishment of a systematic surveillance and legislation is required to iodise all edible salt.

Adolescent↗

PubMed2001

Office-based esophagoscopy: a preliminary report.

OBJECTIVE: Preliminary study that describes unsedated, transnasal esophagoscopy (TNE) in an office setting. STUDY DESIGN AND SETTING: TNE was prospectively performed on 14 consecutive out-patients with dysphagia whose initial oropharyngeal dysphagia evaluation was insufficient to reveal the cause of their swallowing problem. TNE was carried out without conscious sedation while the patients were sitting in an examining chair. Ease of endoscope insertion, optical quality of images, and examination findings were assessed. Heart rate before and after the procedure and incidence of epistaxis and airway compromise was also determined. Patients were asked to rate the level of discomfort of TNE on a validated 10-point scale (1 representing none/well tolerated and 10 severe/poorly tolerated). RESULTS: All patients completed TNE with the esophagus readily intubated and esophageal mucosa clearly visualized. Findings included esophageal stricture, patulous upper esophageal sphincter, and Zenker's diverticulum. There were no incidences of epistaxis or airway compromise and no significant changes in heart rate. Overall tolerance of TNE was rated by the patients as 2.0 (SD, 1.2). CONCLUSIONS: TNE is well tolerated and can be safely performed in patients with dysphagia in an office setting. TNE may have a role in the comprehensive evaluation of the dysphagic patient in the office.

Adult↗

PubMed2001

Broadband vibrational sum frequency generation spectroscopy of a liquid surface.

An important advance in surface science has been the evolution of sum frequency generation to the application of studying surface structure and chemistry of liquid surfaces at the molecular-level by probing the vibrational signatures of surface molecules. Recently, broad-bandwidth sum frequency generation (BBSFG) spectroscopy has become an important tool for investigating gas-solid interfaces. BBSFG spectroscopy allows, theoretically, a surface sum frequency spectrum to be acquired within one pulse of the laser. In this paper, the viability of BBSFG to study inherently small nonlinear response interfaces and the time-resolving capability of this surface-selective technology are demonstrated. Presented here are the first published accounts of spectra from a liquid surface utilizing the broad-bandwidth sum frequency technology with acquisition times as low as 500 milliseconds.

Journal Article↗

PubMed2001

[Polymorphisms of the CYP1A1 and GSTM1 genes and their combined effects on individual susceptibility to lung cancer in a Chinese population].

OBJECTIVE: To investigate the polymorphisms of CYP1A1 and GSTM1 genes as well as their separate and combined effects on individual susceptibility to lung cancer. METHODS: In the matched 106 pairs of patients with lung cancer and non-cancer control persons, genomic DNA were prepared from peripheral blood samples. The genotypes of CYP1A1 Ile/Val and GSTM1+/0 polymorphisms were detected by the allele-specific(AS)-PCR and multidifferential(MD)-PCR. RESULTS: Individuals with genotype Val/Val of CYP1A1, genotype 0/0 of GSTM1, combined genotypes GSTM1 0/0 and CYP1A1 Val/Val, or combined genotypes GSM1 0/0 and CYP1A1 Ile/Val had higher relative risk than those with the corresponding common genotypes and combined genotypes; their odds ratios were 4.02(P=0.03), 1.92(P=0.019), 9.38(P=0.04) and 3.27(P=0.01), respectively. CONCLUSION: There is a synergy of susceptible genotypes GSTM1 0/0 and CYP1A1 Val/Val or CYP1A1 Ile/Val to enhance the individual susceptibility to lung cancer.

Adult↗

PubMed2001

Creating anoxic and microaerobic conditions in sequencing batch reactors treating volatile BTX compounds.

An experimental strategy is introduced for studying the biodegradation of wastewaters containing volatile contaminants using an alternating anoxic/microaerobic sequencing batch reactor (SBR). Benzene, toluene, and the xylene isomers (BTX) served as model volatile contaminants for this study. The reactor was configured to overcome stripping the volatile BTX compounds into the atmosphere to provide opportunities for BTX biodegradation. Oxygen-free anoxic and microaerobic (< 0.2 mg/L dissolved oxygen) conditions were established using a novel laboratory reactor configuration. ORP was successfully used to monitor different electron acceptor conditions in the SBR. Toluene and m-xylene were amenable to anoxic (denitrifying) metabolism while benzene, o-, and p-xylene were biodegradable under microaerobic conditions. The results demonstrate that establishing microaerobic conditions in full-scale bioreactors may be an appropriate way to encourage the biodegradation of aerobically biodegradable volatile contaminants. Additionally, the laboratory reactor configuration introduced in this paper may be useful in subsequent studies involving microaerobic metabolism.

Aerobiosis↗

PubMed2001

[Biological removal of VOCs emissions].

The designed test conditions were following: vacancy velocity was from 0.7 cm/s to 3.5 cm/s, retention time was from 30 s to 80 s. Column activated carbon was selected as the filler of the reactor and toluene was taken as representative of VOCs. The biodegradation of toluene using biofilter reactor and the influence of concentration, flow and humidity on the toluene removal were investigated and the removal model was set up. The experimental results showed that the biofilter reactor had higher toluene removing ability. The observation of biotic community demonstrated that the microbes consisted of fungi, bacillus and spore bacillus. Of them spore bacillus was dominant.

Biodegradation, Environmental↗

PubMed2001

Cost-effectiveness of two types of dysphagia care in head and neck cancer: a preliminary report.

We conducted a prospective, preliminary study to compare the cost-effectiveness of two different instrument-based techniques for diagnosing and managing dysphagia in 30 consecutive hospitalized patients with head and neck cancer. The two techniques are videofluoroscopy via modified barium swallow (MBS) and videoendoscopy via flexible endoscopic evaluation of swallowing with sensory testing (FEESST). Medicare was the primary insurer of all patients. Fifteen of these patients had their dysphagia diagnosed and managed by MBS and the other 15 by FEESST. Cost-effectiveness was assessed by determining the average Medicare reimbursement for each procedure. We found that the mean reimbursements were $451.01 (+/- $50.55) for MBS and $321.23 (+/- $3.01) for FEESST. The mean reimbursement for FEESST was significantly lower than that for MBS (p < 0.0001; Mann-Whitney U test). We conclude that FEESST appears to be more cost-effective than MBS for the inpatient management of dysphagia in patients with head and neck cancer.

Aged↗

PubMed2001

Apolipoprotein E polymorphism in the early onset of coronary heart disease.

OBJECTIVE: To assess the relationship between apolipoprotein E (apoE) polymorphism and the early onset of coronary heart disease (CHD) and the effect of apoE on lipids and lipoproteins in healthy Chinese subjects. METHODS: Sixty-eight patients with CHD younger than 55 years (CHD1), 136 patients with CHD older than 65 years (CHD2), and 136 healthy subjects were enrolled, and their plasma levels of triglyceride (TG), total cholesterol (TC) and high density lipoprotein cholesterol (HDL-C) were determined. The apoE genotypes were identified by polymerase chain reaction-restriction fragment length polymorphism. RESULTS: apoE 3/4 genotype and E4 allele frequency in the CHD1 group were higher than those in the CHD2 group and healthy subjects, while no differences were found between CHD2 and healthy subjects. Meanwhile, the plasma levels of TC and low density lipoprotein cholesterol (LDL-C) were higher in the CHD2 group than in both CHD1 group and healthy subjects. Each apoE isoprotein has variable TC and LDL-C levels that is E2 (E2/2 + E2/3) < E3(E3/3) < E4(E4/4 + E3/4). CONCLUSION: apoE is one of the genetic factors that affect TC and LDL-C levels, and apoE 4 has a very close relation to CHD, suggesting that apoE 4 is an independent genetic factor of the early onset of CHD.

Adult↗

PubMed2001

[Study on specificity of IgM antibody response in patients with coxsackie virus B infection].

OBJECTIVE: To study the specificity of IgM antibody response in patients with Coxsackie virus B infection. METHODS: A Coxsackie virus B specific immunoblot assay was established for detection of CVB IgM antibody response in patients with recent CVB infection. RESULTS: Of 28 patients' serum samples, positive by ELISA captured CVB IgM test, analysis results of specific IgM response defined by immunoblot assay revealed VP1 protein specific which was crossly reactive among CVB group. CONCLUSION: This finding suggested that VP1 protein in Coxsackie virus B group potentially functioned as a predominant antigen inducing detectable IgM antibody following CVB infection.

Antibodies, Viral↗

PubMed2001

[Isolation, purification and identification of metallothionein from strain BD102 of Hansenula anomala].

Metallothionein (MTs) in Cu and Cd resistant strain BD102 of Hansenula anomala were induced by administration of Cu2+ and Cd2+. These proteins were isolated and purified by Sephadex G-50 and subsequent DEAE-Sepharose CL-6B, then Sephadex G-25 for desalation. There were two isoform MTs by Cu(Cu-MTs), one form induced by Cd (Cd-MT). The molecular weights of the Cu-MTs and the Cd-MT were about 7 kD and 7.5 kD respectively. Exposure of Hansenula anomala to copper salts stimulated formation of two isoform Cu-MTs with a cysteine content of 6.6-6.8% and had 60 amino acids. Exposure of Hansenula anomala to cadmium, stimulated formation of Cd-MT with a cystein content of 10% was synthesized and had 61 amino acids. 4 atom Cu or Cd/mole MTs.

Amino Acids↗

PubMed2001

[The characterization of pJW566 from L. Lactis subsp. cremoris W56].

The plasmid pJW566 was isolated from L. lactis subsp. cremoris W56, one strain for Danish chadder mixed starter cultures. The strain containing plasmid pJW566 showed resistance against three common phages species 936, c2 and P335 worldwide. It was found that pJW566 encoded for an restriction and modification system, and showed strong resistance to phage CHCP412 when it was introduced into the industrial strain L. lactis CHCC2281 in milk medium. The endonuclease activity analysis indicated that the endonuclease required Mg2+, ATP, and was stimulated by AdoMet.

Animals↗