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PubMed2006

Site-specific nucleation and growth kinetics in hierarchical nanosyntheses of branched ZnO crystallites.

Here we report a site-specific sequential nucleation and growth route to the systematic building of hierarchical, complex, and oriented ZnO micro/nanostructures in solution nanosynthesis. Structures and morphologies of the products were confirmed by results from X-ray diffraction and scanning electron microscopy studies. The organic structure-directing agents (SDAs), diaminopropane and citrate, are found to play different roles in controlling the evolution of these new morphologies. Through the selective adsorptions of SDAs on different crystal facets of the primary ZnO rods, we have alternated the hierarchical growth of secondary and tertiary new complex nanostructures. Roles of the SDA concentration, nucleation time, and growth kinetics in the solution hierarchical ZnO nanosyntheses have all been systematically investigated.

Journal Article↗
PubMed2006

Folded and unfolded conformations of the omega-3 polyunsaturated fatty acid family: ch(3)ch(2)[ch=chch(2)](b)[ch(2)](m)cooh: first principles study.

Polyunsaturated fatty acids (PUFA) like stearidonic acid (SDA;18:4 n-3) eicosapentaenoic acid (EPA; 20:5 n-3), and docosahexaenoic acid (DHA; 22:6 n-3) and its chain fragment models were studied at B3LYP/6-31G(d) levels of theory. Significant conformations for the cis and trans isomers were selected to obtained the thermodynamic functions (DeltaH, DeltaS, DeltaG) for the cis-trans isomerization and for folding using the B3LYP/6-311+G(2d,p)//B3LYP/6-31G(d) level of theory. The structural analysis shows that there are significant differences in thermodynamic function of the trans- and cis-PUFAs. The trans-cis isomerization energy values reinforce the consistency and the relative accuracy of theoretical model calculations. The observed flexibility of naturally cis PUFAs could be explained by a very special "smooth basin" PES of the motif of sp(2)-sp(3)-sp(2) hybrid states as reported previously (J. Phys. Chem. A 2005, 109, 520-533). We assumed that intrinsic thermodynamic functions may describe this flexible folding process. The folding enthalpy as well as the folding entropy suggests that there is a new role of the cis-PUFAs in membranes: these cis isomers may have a strong influence on membrane stability and permeability. The average length of the cis helix and beta PUFA was approximated. The difference between the lengths of these two structures is approximately 10 A.

Computer Simulation↗
PubMed2002

Access to microdata on the Internet: Web-based analysis and data subset extraction tools.

The Internet is increasingly being recognized as an invaluable component of education. At the college and university level, online databases and statistical tools for Web-based analysis and data subset extraction have become important instructional resources. These Internet resources enable students to formulate specific research hypotheses, identify relevant variables, and analyze large existing databases. This article describes three of these resources: the Federal Electronic Research and Review Extraction Tool (FERRET) of the U.S. Bureau of the Census, the Survey Documentation and Analysis (SDA) unit at the University of California, Berkley, and the Inter-University Consortium for Political and Social Research (ICPSR), which is housed at the University of Michigan.

California↗
PubMed1985

Comparative study of glycophorin A derived O-glycans from human Cad, Sd(a+) and Sd(a-) erythrocytes.

Glycophorin A was purified from the erythrocyte membranes of blood group Cad, Sd(a+) and Sd(a-) donors and the oligosaccharide alditols, obtained after alkaline borohydride degradation, separated by h.p.l.c. on an alkylamine silica gel column, were characterized by sugar analysis. Structure determination of the major acid components by methylation analysis, g.l.c.-m.s. and 1H-n.m.r. indicated that the three blood group Cad red cells under study (samples Cad., Bui. and Des.) carry the same pentasaccharide GalNAc(beta 1-4)[NeuAc(alpha 2-3)]Gal(beta 1-3)[NeuAc(alpha 2-6)]GalNAc -ol(Cad determinant) but in different amounts. This pentasaccharide, however, was absent from glycophorin A of Sd(a+) and Sd (a-) donors, suggesting that the Sda determinant is not associated with glycophorins. It was calculated that glycophorin A from the original Cad donor (Cad.) carries about 12 O-glycosidically linked pentasaccharide chains per molecule whereas only 2-3 of these chains were present in the samples from the two other unrelated Cad individuals (Bui. and Des.) It is well known from quantitative agglutination studies that the proportion of red cells which can be agglutinated by the Dolichos biflorus lectin varies from one Cad blood sample to another. Some are completely agglutinated (Cad. donor) whereas others are only partially agglutinated (Bui. and Des. donors) suggesting that some red cells might not carry the Cad determinants. From the results presented above and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis studies it is suggested that Cad red cells from Bui. and Des. do not carry a mixture of glycophorin A molecules with or without the Cad pentasaccharides but a spectrum of glycoprotein molecules with varying amounts of Cad determinants.

Blood Group Antigens↗
PubMed1986

Oligosaccharides obtained from a blood-group-Sd(a+) Tamm-Horsfall glycoprotein. An n.m.r. study.

Treatment of Tamm-Horsfall urinary glycoprotein with Bacteroides fragilis endo-beta-galactosidase over a range of enzyme concentrations, pH and temperature resulted in the release of a small but constant proportion of the terminal sugars, which indicates the presence in the glycoprotein of relatively few enzyme-susceptible -GlcNAc beta 1-3Gal beta 1-4GlcNAc- units. Three oligosaccharides were isolated from the enzyme digest and characterized as Gal beta 1-4GlcNAc beta 1-3Gal, NeuAc alpha 2-3Gal beta 1-4 GlcNAc beta 1-3Gal and GalNAc beta 1-4(NeuAc alpha 2-3)Gal beta 1-4GlcNAc beta 1-3Gal by methylation analysis and exo-glycosidase digestion. The alditols of these oligosaccharides and related structures were examined by 500 MHz 1H-n.m.r. spectroscopy aided by spin-spin decoupling and two-dimensional correlated spectroscopy. An almost complete assignment of proton shifts was possible, and significant differences between the signals of some of the protons in the blood-group-Sda-active oligosaccharide III and literature values for the corresponding signals in the structurally related Cad-blood-group determinant are noted.

Blood Group Antigens↗
PubMed1999

Indoor survey of moulds and prevalence of mould atopy in Israel.

BACKGROUND: Moulds are ubiquitous indoor as well as outdoor allergens and therefore potential candidates for indoor environmental control measures. However, very few studies have been performed to examine the significance of indoor moulds in allergic diseases and the effectiveness of measures to reduce the quantity of indoor moulds has not been established. OBJECTIVE: To determine the significance and the contribution of moulds to allergic manifestations. METHODS: Prevalence of allergic rhinitis and asthma in 395 members of a rural community were examined by questionnaire and examination of medical files. The atopic status in general and allergy to moulds was determined by skin-prick tests (SPTs) to a panel of aeroallergens including Aspergillus, Penicillium, Alternaria and Cladosporium. A study of indoor mould levels was performed by placing SDA plates in 59 houses. The type of fungi and the number of colonies from each species were recorded. RESULTS: Forty-two subjects, comprising 10.9% of the study group had positive SPT to moulds, 61.9% of those were classified as symptomatic. When taking into account individuals with a borderline positive SPT to moulds, an additional 23 had positive results. Of the 65 mould-positive subjects, 48% were symptomatic and of the 13 who were allergic to moulds alone, only two had allergic symptoms. Viable moulds were recovered from all 59 houses examined. The most common isolated genus was Aspergillus, followed by Penicillium, Alternaria and Cladosporium. Aspergillus was also the most abundant mould in houses. There was no significant correlation between the abundance of moulds, positive SPT to that mould and symptomatology. CONCLUSIONS: Viable moulds are common in houses in temperate climates. Allergy to moulds itself has a low predictive value to development of allergic symptoms, but allergy to moulds in otherwise atopic subjects increases the risk of symptomatic allergic disease.

Adolescent↗
PubMed2001

Characterization of polar lipids of oral isolates of Candida, Pichia and Saccharomyces by Fast Atom Bombardment Mass Spectrometry (FAB MS).

AIMS: To characterize fatty acid and phospholipid analogue profiles of oral yeasts. METHODS AND RESULTS: Twenty-seven strains of oral yeasts were cultured on SDA and lipids of freeze-dried cells were extracted and analysed by FAB MS. The most abundant carboxylate anion was m/z 281 (C18 : 1). The most intense phospholipid analogue ions were of PE, PG, PA and PI. Pichia etchellsii contained molecular species of PG and PE, whereas Saccharomyces cerevisiae had PA, PG and PE analogues. Mass spectra revealed that S. cerevisiae and Candida glabrata were distinct from one another and from the other species tested. CONCLUSION: Oral yeasts largely differ with respect to their polar lipids. It is concluded that oral yeast species have distinctive fatty acid and phospholipid analogue anion profiles. SIGNIFICANCE AND IMPACT OF THE STUDY: FAB MS provided novel chemotaxonomic information.

Anions↗
PubMedDate not supplied

Autoagglutinins with apparent anti-P specificity reactive only by low-ionic-strength salt techniques.

Two blood samples containing autoagglutinins reactive in room temperature tests using low-ionic strength salt (LISS) reagents, but not by conventional saline-albumin or enzyme tests, are reported. The anti-P specificity of both sera, when tested near or diluted in group AB serum, was evident by their failure to agglutinate LISS-suspended Tj(a-),(p), and P1 red blood cells. However, one of the two samples displayed no anti-P specificity when diluted in LISS solution as opposed to group AB serum. Some urine samples inhibited this latter serum. Inhibition did not correlate with urinary Sda antigen content, nor with pH, Na+, K+, C1-, or osmolality levels. However, there was some correlation between inhibition and urinary conductivity levels. Moreover, partial inhibition was observed in tests with globoside. While there are no data to indicate that these LISS-dependent autoagglutinins are of clinical consequence in vivo, it is likely that they represent low-affinity autoantibodies reacting only in a low-ionic environment. They establish a further cause of anomalous serologic reactions associated with LISS techniques.

Adolescent↗
PubMedDate not supplied

Depressed blood group antigens on red cells from a Mexican donor.

Red cells from a Mexican blood donor had depressed H, IF, ID, i, Sda, Sdx, D, LW, Dib, Vel and JMH antigens. A wide range of other blood group antigens had normal activity. The unusual red cell phenotype may be caused by a membrane anomaly that alters orientation of certain cell surface components. The specificities of the depressed red cell antigens in this phenomenon differ from those affected in Melanesians with ovalocytosis or in individuals with the In(Lu) inhibitor gene.

ABO Blood-Group System↗
PubMed1994

Polyethylene glycol versus low-ionic-strength solution in pretransfusion testing: a blinded comparison study.

BACKGROUND: Polyethylene glycol (PEG) has been shown to potentiate antigen-antibody reactions. STUDY DESIGN AND METHODS: To investigate the utility of PEG in pretransfusion testing, a blinded comparison study of PEG and a low-ionic-strength additive solution (LISS) was conducted. A total of 500 patient samples were tested in parallel with reagent antibody-detection cells using blind-coded PEG and LISS potentiators. RESULTS: In 34 (34%) of 100 samples with known antibodies in the Rh, Kell, Duffy, Kidd, and MNS systems, PEG antiglobulin reactions were stronger (total score, 382) than LISS antiglobulin reactions (total score, 216), and in 66 cases (66%), they were equal to those of LISS. Of 400 samples without detectable antibodies, 384 were negative with PEG and LISS, and 16 were positive in PEG tests and negative in LISS. Seven of the 16 were clinically important antibodies (D, 1; E, 3; Fya, 1; Jka; 1; Jkb, 1), and four were clinically benign antibodies (Le(a), 2; McCc, 1; Sda, 1). Five of the 16 demonstrated inconclusive PEG reactions, for a false-positive rate of 5 in 400 (1.3%). Of the 500 samples, none was negative in PEG tests and positive in LISS (0% false-negative rate). CONCLUSION: Although PEG demonstrates a relatively high false-positive rate, PEG is more sensitive than LISS in detecting clinically significant antibodies.

Blood Transfusion↗
PubMed2002

Computers in clinical practice: screening renal patients for abnormal biochemistry and malnutrition.

OBJECTIVE: Develop and compare a computer program (CP) and a screening tool (ST) to determine the best method of identifying patients undergoing hemodialysis (HD) who are at risk of malnutrition. Investigate the benefits of using the CP to screen biochemical test results of patients undergoing HD, continuous ambulatory peritoneal dialysis (CAPD), nephrology patients, and transplant recipients for abnormal levels, such as hyperkalemia. DESIGN: The CP was designed by using the program Proton (Clinical Computing Clinical Information Systems, Middlesex, England). Proton can automatically download biochemical results from pathology, making it possible to generate a list of patients with results outside a desired biochemical range in accordance with national renal standards for adult patients. Biochemical measures of nutritional status were used to define malnutrition as 2 or more results outside of these parameters: 10% weight loss; Kt/V < 1.1; predialysis urea, <20 mmol/L; phosphate, <0.75 mmol/L; and potassium, <3.3 mmol/L. One hundred eighty-four HD patients were incidentally screened for their risk of malnutrition by using both the CP and the ST. SETTING: Richard Bright Renal Unit, Bristol, England, and 4 satellite HD units in Southwest England. PATIENTS: Three thousand five renal outpatients, including 468 patients with diabetes, had blood test results screened by the CP for abnormal levels. This included 235 HD patients (unit A, n = 32; unit B, n = 58; unit C, n = 70; Unit D, n = 24; home HD unit, n = 51), 88 CAPD patients, 416 transplant recipients, and 2,266 nephrology patients. MAIN OUTCOME MEASURE: The CP and the ST were compared with standardized dietetic assessments (SDAs) for validity. In the clinic setting, the length of time taken to review biochemical test results was measured before and after implementation of the CP. RESULTS: The CP identified 36% of HD patients at risk of malnutrition, compared with 20% by the ST and 42% by SDA. However, only 57% of the STs were completed. The CP found 42% of transplant recipients and 92% of nephrology patients have glycosylatid hemoglobin levels >7, and 16% of HD patients have fluid weight gains >3 kg on 4 or more occasions in a month. CONCLUSION: Using the present parameters, the CP is not sensitive enough to correctly identify all HD patients at risk of malnutrition. Screening for serum cholesterol, prealbumin, protein equivalent of total nitrogen appearance, and C-reactive protein levels should be incorporated into the CP to compare it with a simple, inexpensive, and reproducible screening tool, such as subjective global assessment, to identify malnutrition in patients undergoing dialysis. The CP improves time management and rationalization of dietetic activity by screening abnormal biochemistry levels. Renal dietitians are urged to investigate the practicalities and the benefits of computers in clinical practice because early identification of malnutrition in patients allows dietitians to work in a more proactive manner.

Adult↗
PubMed2003

Murine and human zona pellucida 3 derived from mouse eggs express identical O-glycans.

Murine sperm initiate fertilization by binding to the outer covering of the egg known as the murine zona pellucida (mZP). This binding is thought to require the interaction of O-glycans linked to a specific mZP glycoprotein (mZP3) with egg-binding proteins coating the sperm plasma membrane. The precise molecular basis of this interaction remains to be resolved. In this study, we analyzed the O-glycosylation of the individual mZP glycoproteins by using ultrasensitive MS methods. We found that the majority of the O-glycans that are linked to mZP3 are core type 2 sequences terminated with sialic acid, lacNAc (Galbeta1-4GlcNAc), lacdiNAc (Gal-NAcbeta1-4GlcNAc), Galalpha1-3Gal, and NeuAcalpha2-3[GalNAcbeta1-4]Galbeta1-4 (Sda antigen). Many of these terminal sequences have been implicated previously in murine sperm-egg binding. Core type 1 O-glycans are also present and are generally unmodified, although some are terminated with sialic acid, beta-linked N-acetylhexosamine, or NeuAcalpha2-3[GalNAcbeta1-4]Galbeta1-4. Eggs expressing human ZP (huZP) glycoprotein huZP3, derived from transgenic mice, bind murine but not human sperm, implying that huZP3 acquires the same O-glycans as native mZP3. Sequencing of huZP3-associated O-glycans confirms that this implication is correct. The data obtained in this investigation may prove to be very useful for studies to determine the precise molecular basis of initial murine sperm-egg binding.

Animals↗
PubMedDate not supplied

Chronic obstructive pulmonary disease symptom effects of long-term cumulative exposure to ambient levels of total oxidants and nitrogen dioxide in California Seventh-Day Adventist residents.

To assess the risk of chronic obstructive pulmonary disease symptoms due to long-term exposure to ambient levels of total oxidants and nitrogen dioxide (NO2), symptoms were ascertained using the National Heart, Lung, and Blood Institute (NHLBI) respiratory symptoms questionnaire. A total of 7,445 Seventh-day Adventist (SDA) nonsmokers who were 25 yr of age or older and had resided at least 11 yr in areas of California with high to low photochemical air pollution were included in this study. Cumulative exposures to each pollutant in excess of four thresholds were estimated for each participant, using zip codes for months of residence and interpolated dosages from state air-monitoring stations. Multiple logistic regression analyses were conducted individually and together for pollutants and included eight covariables, including passive smoking. A statistically significant association with chronic symptoms was seen for total oxidants above 10 pphm (196 mcg/m3) (p less than .004, relative risk of 1.20 for 750 hr/yr). Chronic respiratory disease symptoms were not associated with relatively low NO2 exposure levels in this population. When these pollutant exposures were studied with exposures to total suspended particulates (TSP) and sulfur dioxide (SO2), only TSP exposure above 200 mcg/m3 showed statistical significance (p less than .01). Exposure to TSP is either more strongly associated with symptoms of chronic obstructive pulmonary disease than the other measured exposures or is the best single surrogate representing the mix of pollutants present.

Adult↗
PubMedDate not supplied

Estimated long-term ambient concentrations of PM10 and development of respiratory symptoms in a nonsmoking population.

Site- and season-specific regressions of particulates less than 10 mu in diameter (PM10) on total suspended particulates (TSPs) were formed throughout California during years when both were monitored. The regressions were then applied to monitored TSPs for the years 1973 to 1987, and indirect estimates of PM10 were formed. These estimates of PM10 were validated by interpolating them to other monitoring stations. The split-halves correlation between the estimated and monitored mean concentrations, obtained when both were first cumulated for a 2-y period, was .86. Indirect estimates of PM10 at monitoring stations were interpolated, by month, to zip code centroids of home and work location and were cumulated for a cohort of 3,914 California Seventh-day Adventist (SDA) nonsmokers. Multivariate analyses, adjusted for several covariates, showed statistically significant (p < .05), but small, positive associations between PM10 and development of (a) definite symptoms of overall airway obstructive disease, (b) chronic productive cough, and (c) increased severity of airway obstructive disease and asthma. The relative risk (RR) associated with 1,000 h/y (42 d) exposure to concentrations of PM10 that exceeded 100 micrograms/m3 for development of airway obstructive disease was 1.17 (95% confidence interval [CI]: 1.02, 1.33); for development of productive cough, the RR was 1.21 (CI 1.02, 1.44); and for development of asthma, the RR was 1.30 (CI, 0.97, 1.73). Stronger associations were observed for those who were exposed occupationally to dusts and fumes. The RR of developing airway obstructive disease as an adult for those who had airway obstructive disease as a child was 1.66 (CI 1.15, 2.33).

Adult↗
PubMed2005

An in situ single-pass perfusion model for assessing absorption across the intestinal mucosa of the brushtail possum.

AIM: To develop an in situ animal model for assessing absorption of molecules across the intestinal mucosa of possums. METHODS: A surgical preparation was used to perfuse known concentrations of reference compounds (fluorescein and luteinising hormone-releasing hormone; LHRH) through measured sections of selected regions (jejunum, caecum, proximal colon) of the intestinal tract of 19 possums, over a 2-h period. Plasma concentrations of the compounds, which were perfused either with or without co-administration of a permeation enhancer (sodium deoxycholic acid; SDA), were determined in the perfusion effluent, peripheral and in some instances in the pre-hepatic circulation by spectrofluorometry (fluorescein) or radioimmunoassay (LHRH). Pharmacokinetic parameters of both compounds in the possum were determined over a period of up to 4 h in a further 30 animals (fluorescein, n = 6; LHRH n = 24), from their plasma profiles following intravenous (I/V) administration of a bolus dose. RESULTS: In animals perfused with 25 mg/ml fluorescein (Perfusion Experiment (PE) 1), the mean plasma concentration was 2.8 (SE 0.12) microg/ml in post-hepatic blood samples. When possums were perfused with 2.5 mg/ml fluorescein and 7 microg/ml LHRH (PE 2), mean plasma concentrations were 0.3 (SE 0.01) and 7.8 (SE 1.64) microg/ml fluorescein and 0.1 (SE 0.02) and 6.3 (SE 0.45) ng/ml LHRH, in the absence and presence of permeation enhancer, respectively. There was a poor correlation between pre-hepatic and post-hepatic concentrations. CONCLUSIONS: The single-pass in situ perfusion technique provided a useful model for investigating basic information on the absorption of biocontrol agents across the intestinal tract of possums, but had limitations that must be recognised.

Animals↗
PubMed2006

A chemometric study of megazol derivatives with activity against Trypanosoma equiperdum.

The AM1 semiempirical method was employed to study megazol and 13 of its analogues where their activity against Trypanosoma equiperdum was obtained from in vitro tests. Several molecular properties (descriptors or variables) were calculated for the 14 compounds studied to be correlated with the biological activity. For a practical analysis of large data sets, it is necessary to reduce the dimensionality and select the most relevant descriptors related to the biological activity under study. For this purpose, the following chemometric methods were employed: principal component analysis (PCA), hierarchical cluster analysis (HCA), K-nearest neighbour (KNN), stepwise discriminant analysis (SDA) and soft independent modelling of class analogy (SIMCA). These methods showed that the descriptors molecular electronic energy (Eelet), charge on the first nitrogen at substituent 2 (qN), volume of substituent at C5 position (V-S5), dihedral angle (D3) and bond length between atom C4 and its substituents (L4) are responsible for the separation between active and inactive compounds against T. equiperdum.

Animals↗
PubMed1976

The serological classification of Neisseria gonorrhoeae. I. Isolation of the outer membrane complex responsible for serotypic specificity.

Neisseria gonorrhoeae has been subdivided into several classes of serological distinct groups. The serotyping system is based upon the antigenic specificity of a protein serotype antigen. This protein is the major polypeptide of the outer membrane of the gonococcus and accounts for over 60% of that membrane's total protein. The serotype antigen complex was isolated by mild extraction of intact organisms in 200 mM lithium acetate buffer, pH 6.0 with 10 mM EDTA for 2 h at 45 degrees C. The extract was fractionated on Sepharose 6B and partially purified by precipitation at pH 4.2 by addition of 10% (vol/vol) acetic acid. Each serotype antigen has a unique subunit molecular size as determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Preliminary typing of a gonococcal strain may be performed by comparative SDA-PAGE. To date, 16 different serotypes, representing a diverse distribution, have been isolated.

Antibody Specificity↗