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L Copeland

Publications and source records attributed to L Copeland.

At least 19 recordsLinked to original sources
PubMed2006

Nanostructural analysis of starch components by atomic force microscopy.

Morphological and structural features of starch from potato (Solanum tuberosa) and rice (Oryza sativa) have been examined using atomic force microscopy. Amylose from potato and rice was observed in aggregated structures, which are suggested to be a result of retrogradation during sample preparation. The degrees of polymerization of amylose from potato and rice starches were calculated from the mean contour lengths of the observed structures to be approximately 1440 and 1860, respectively. Potato amylopectin appeared as a highly branched and extended molecule. Our results show that atomic force microscopy provides a useful method for examining the fine structural features and estimating the dimensions of starch molecules.

Amylopectin↗
PubMed2005

What happens when GPs proactively prescribe NRT patches in a disadvantaged community.

BACKGROUND AND AIMS: The high prevalence of smoking in disadvantaged communities gives serious cause for concern in terms of adverse effects on health and social outcomes. In Scotland, smoking -related lung cancer rates are particularly high and compare less favourably with the rest of the U.K. and Europe. GPs are increasingly being recognised as having an important role in smoking cessation and are allowed to prescribe NRT to those on a low income. This study aimed to follow up a group patientsfrom a disadvantaged area who had been prescribed nicotine patches by their GP. METHODS: An initial self-complete questionnaire gathered details on age, sex, motivation, marital status, employment history, contact with other smokers, concern about weight gain, and nicotine dependence. (Nicotine dependence was assessed by using the Fagerstrom Test). Follow up was carried out at three months after commencing NRT prescription. Data was also gathered from patient case notes as to whether the participant had a smoking-related diagnosis, periods of depression, drug and/or alcohol problems. Outcome was measured in terms of "smoke the same", "smoke less" and "stopped". The statistical methods used for testing each factor against smoking were Spearman rank correlation, chi-squared test for trend and Kruskal-Wallis test. Basic descriptive statistics were used to report general outcomes of the study. RESULTS: The study enrolled 120 patients but 19 were lost to follow up. Out of 101 who used their prescription, 35 were smoking the same, 46 were smoking less and 20 had stopped. The variables most strongly affecting outcome were age, with older smokers having more success (p < 0.001), and those who had a diagnosis of depression having a worse outcome in terms of smoking cessation (p < 0.05). CONCLUSION: This study's findings indicate that encouraging GPs to take a proactive approach in prescribing NRT is effective, even in an area of socio-economic deprivation, and particularly with older smokers.

Administration, Cutaneous↗
PubMed2001

The wheat-grain proteome as a basis for more efficient cultivar identification.

The wheat-grain proteome was investigated, as a basis for devising more efficient methods of cultivar identification or discrimination. Australian wheats (Halberd, Cranbrook, CD87 and Katepwa) were used as the basis of this study. These cultivars were selected on the basis of differences in the quality types represented, in terms of dough-processing attributes that can suit one cultivar better than another for specific types of industrial utilisation. Total wheat endosperm (flour) protein extracts were prepared from mature wheat for two-dimensional electrophoresis, across both acidic (pH 4-7) and basic (pH 6-11) pH ranges. Three particular regions of the proteome maps were chosen for close comparison, involving two sets of gluten proteins and a nongluten protein region (involving small heat shock proteins), based on previous protein characterisation. Differences in the nongluten protein regions (heat shock proteins and other unidentified polypeptides) are of particular interest as being possible targets for use in developing new approaches to cultivar discrimination, such as the development of simple immunoassays.

Electrophoresis, Gel, Two-Dimensional↗
PubMed2001

Characteristics and correlates of asthma knowledge among emergency department users in Harlem.

We constructed a questionnaire to assess asthma knowledge, assessed its psychometric properties, and examined its association with demographic characteristics, psychosocial factors, and disease severity and management in 375 adults following an asthma-related emergency department visit. Overall knowledge was poor but varied widely among respondents. Better knowledge was related to younger age, higher education, and less severe disease. Chance-orientated health locus of control and low self-esteem were associated with lower asthma knowledge. Better knowledge was associated with better disease management. We conclude that asthma education can lead to improved disease outcomes, and psychosocial factors need to be considered when designing interventions for asthma education.

Adult↗
PubMed2001

Delays in adopting evidence-based dosages of conventional antipsychotics.

By the 1980s, strong research evidence had emerged supporting the use of moderate doses of conventional antipsychotics-between 300 and 1,000 mg of chlorpromazine equivalent daily. We conducted a cross-sectional study of dosages of antipsychotics prescribed for 936 veterans with schizophrenia in 14 facilities between 1991 and 1995. Only 52 percent of these patients received prescriptions for recommended dosages; dosages were below the recommended range for 20 percent and above the range for 28 percent. African Americans were more likely than others to have received high dosages. These data suggest that there was considerable delay in the adoption of evidence-based dosing of conventional antipsychotics. Efforts must be made to transfer research findings more rapidly into practice.

Adult↗
PubMed2000

Biochemical controls of citrate synthase in chickpea bacteroids.

Bacteroids formed by Mesorhizobium ciceri CC 1192 in symbiosis with chickpea plants (Cicer arietinum L.) contained a single form of citrate synthase [citrate oxaloacetate-lyase (CoA-acetylating) enzyme; EC 4.1.3.7], which had the same electrophoretic mobility as the enzyme from the free-living cells. The citrate synthase from CC 1192 bacteroids had a native molecular mass of 228 +/- 32 kDa and was activated by KCl, which also enhanced stability. Double reciprocal plots of initial velocity against acetyl-CoA concentration were linear, whereas the corresponding plots with oxaloacetate were nonlinear. The Km value for acetyl-CoA was 174 microM in the absence of added KCl, and 88 microM when the concentration of KCl in reaction mixtures was 100 mM. The concentrations of oxaloacetate for 50% of maximal activity were 27 microM without added KCl and 14 microM in the presence of 100 mM KCl. Activity of citrate synthase was inhibited 50% by 80 microM NADH and more than 90% by 200 microM NADH. Inhibition by NADH was linear competitive with respect to acetyl-CoA (Kis = 23.1 +/- 3 microM) and linear noncompetitive with respect to oxaloacetate (Kis = 56 +/- 3.8 microM and Kii = 115 +/- 15.4 microM). NADH inhibition was relieved by NAD+ and by micromolar concentrations of 5'-AMP. In the presence of 50 or 100 mM KCl, inhibition by NADH was apparent only when the proportion of NADH in the nicotinamide adenine dinucleotide pool was greater than 0.6. In the microaerobic environment of bacteroids, NADH may be at concentrations that are inhibitory for citrate synthase. However, this inhibition is likely to be relieved by NAD+ and 5'-AMP, allowing carbon to enter the tricarboxylic acid cycle.

Citrate (si)-Synthase↗
PubMed2000

Role of malonate in chickpeas.

Analysis of the content and distribution of organic acids in chickpea plants (Cicer arietinum L.) showed that malonate was the most abundant acid in roots and nodules, whereas malate was the main acid in leaves and stems. The highest concentration of malonate in roots was in the apices. Malonate metabolism did not appear to be directly related to abiotic stress. We suggest that malonate has a role as a defensive chemical in roots and nodules of chickpeas.

Fabaceae↗
PubMed2000

Inhibition of enzymic digestion of amylose by free fatty acids in vitro contributes to resistant starch formation.

The effect of lipids on the enzymic breakdown of starch was investigated using an in vitro assay system. Mixtures of potato amylose, amylopectin and starch and various lipids were incubated at 37 degrees C for 10 min and subjected to digestion by alpha-amylase (EC 3.2.1.1) and amyloglucosidase (EC 3.2.1.33). Lauric, myristic, palmitic and oleic acids and lysolecithin inhibited enzymic hydrolysis of amylose by approximately 35% (P < 0.05). Stearic acid and cholesterol had no effect on the enzymic breakdown of amylose. Retrograded amylose was hydrolyzed less readily (P < 0.05) than solubilized amylose, but the breakdown was not further inhibited in the presence of lauric acid. Fatty acids had no effect on the enzymic hydrolysis of amylopectin, whereas inhibition by fatty acids of the breakdown of whole starch was consistent with only the amylose fraction being affected. The possibility that interactions between starch and fatty acids in the digestive tract could contribute to the formation of resistant starch is considered.

Amylose↗
PubMed1998

The use of fluoroscopy to guide needle placement in interstitial gynecological brachytherapy.

PURPOSE: Interstitial brachytherapy is generally performed for gynecological malignancies with extensive parametrial involvement, by inserting the needles through a transperineal template. Often, the implanted needles are not parallel, and the multiple sources can be difficult to identify on localization radiographs, especially if obtained with a portable X-ray unit. We have used fluoroscopy to guide the needles for interstitial brachytherapy to treat various gynecological malignancies. Because the resultant needles are parallel, dosimetry can be performed based on the template hole positions used, rather than identifying individual sources. This report focuses on the technique; the outcome of patients implanted with this technique will be reported separately. METHODS: Seventy-one patients were implanted transperineally with 192iridium using a Syed template under fluoroscopic guidance, from September 1989 to May 1995, for bulky parametrial disease, narrow vagina, extensive vaginal involvement, recurrent disease after previous course of pelvic radiation therapy, or in cases in which the patient had previously undergone hysterectomy. 137Cesium was added in a central tandem in cases with a cervical os. Thirty patients were treated for primary cervical or vaginal carcinoma; 41 patients were treated for recurrent disease from endometrial or cervical cancers. The brachytherapy dose (prescribed to the periphery of the implant) was 40 to 55 Gy when used alone (15 patients) and 22-40 Gy when used as a boost to 34.2 to 59.4 Gy of pelvic external-beam radiotherapy (56 patients). The patients were followed for 6 to 63 months. RESULTS: In all cases, some of the needles had to be repositioned to improve the alignment. Hence, the use of fluoroscopy aided in achieving parallel placement of the needles in all implants as seen on anterior-posterior radiographs. Because the 192iridium sources were ordered beforehand based on the preplan, and the dosimetry was based on idealized geometry of the template hole positions, all patients were loaded on the same day of implant. CONCLUSION: Fluoroscopically guided perineal interstitial brachytherapy is a feasible technique for use in various gynecological malignancies. The use of fluoroscopic guidance helped to achieve parallel needle placement in all of our implants, but it required repositioning of some of the needles in all cases. The parallel positioning allowed the use of preplanned dosimetry, minimizing the delay in loading of the patients. The outcome of the patients treated using this technique is currently undergoing analysis and will be reported separately.

Brachytherapy↗
PubMed1998

Acetoacetyl coenzyme A reductase and polyhydroxybutyrate synthesis in rhizobium (Cicer) sp. Strain CC 1192

Biochemical controls that regulate the biosynthesis of poly-3-hydroxybutyrate (PHB) were investigated in Rhizobium (Cicer) sp. strain CC 1192. This species is of interest for studying PHB synthesis because the polymer accumulates to a large extent in free-living cells but not in bacteroids during nitrogen-fixing symbiosis with chickpea (Cicer arietinum L.) plants. Evidence is presented that indicates that CC 1192 cells retain the enzymic capacity to synthesize PHB when they differentiate from the free-living state to the bacteroid state. This evidence includes the incorporation by CC 1192 bacteroids of radiolabel from [14C]malate into 3-hydroxybutyrate which was derived by chemically degrading insoluble material from bacteroid pellets. Furthermore, the presence of an NADPH-dependent acetoacetyl coenzyme A (CoA) reductase, which was specific for R-(-)-3-hydroxybutyryl-CoA and NADP+ in the oxidative direction, was demonstrated in extracts from free-living and bacteroid cells of CC 1192. Activity of this enzyme in the reductive direction appeared to be regulated at the biochemical level mainly by the availability of substrates. The CC 1192 cells also contained an NADH-specific acetoacetyl-CoA reductase which oxidized S-(+)-3-hydroxybutyryl-CoA. A membrane preparation from CC 1192 bacteroids readily oxidized NADH but not NADPH, which is suggested to be a major source of reductant for nitrogenase. Thus, a high ratio of NADPH to NADP+, which could enhance delivery of reductant to nitrogenase, could also favor the reduction of acetoacetyl-CoA for PHB synthesis. This would mean that fine controls that regulate the partitioning of acetyl-CoA between citrate synthase and 3-ketothiolase are important in determining whether PHB accumulates.

Journal Article↗
PubMed1998

Agreement between seriously mentally ill veterans and their clinicians about medication compliance.

OBJECTIVES: Levels of agreement about medication compliance in a large cohort of seriously mentally ill veterans and their clinicians were examined to determine whether agreement increased with exposure to enhanced treatment programs emphasizing compliance and whether compliance reports were associated with hospitalization. METHODS: A total of 1,369 seriously mentally ill patients and their treating clinicians at 14 Veterans Affairs medical centers rated medication compliance at enrollment in enhanced programs or comparison programs offering standard care. Patients and clinicians reassessed compliance one and two years after enrollment. Overall agreement, agreement about compliance and noncompliance, and kappa statistics were determined for concurrent assessments. RESULTS: Overall, patients rated themselves as significantly more compliant with medication than did clinicians at enrollment. Cohen's kappa at enrollment was .095, indicating little patient-clinician agreement beyond that expected by chance. Kappa values increased significantly at one and two years for patients in the enhanced programs but continued to indicate poor-to-modest levels of agreement. Patient-clinician pairs in enhanced programs did not differ from those in comparison programs in overall agreement. Reports of good compliance by both patients and clinicians were associated with significantly decreased odds of hospital admission in the 30 days after the report was made. CONCLUSIONS: Seriously mentally ill patients and their clinicians showed little agreement about medication use beyond that expected by chance. Intensive programming appeared to have little effect on agreement. Both patients' and clinicians' compliance assessments predicted hospitalization and thus can be used in research models that attempt to predict relapse and readmission.

Adult↗
PubMed1997

Acetyl Coenzyme A Acetyltransferase of Rhizobium sp. (Cicer) Strain CC 1192.

To investigate why Rhizobium sp. (Cicer) strain CC 1192 cells accumulate poly-R-3-hydroxybutyrate in the free-living state but not as bacteroids in nodules on chickpea (Cicer arietinum L.) plants, we have examined the kinetic properties of acetyl coenzyme A (acetyl-CoA) acetyltransferase (also known as acetoacetyl-CoA thiolase and 3-ketothiolase [EC 2.3.1.9]) from both types of cells. The enzyme had a native molecular mass of 180 (plusmn) 4 kDa, and the subunit molecular mass was 44 (plusmn) 1 kDa. The seven amino acids from the N terminus were Lys-Ala-Ser-Ile-Val-Ile-Ala. Thiolysis and condensation activity of the enzyme from free-living CC 1192 cells were optimal at pHs 7.8 and 8.1, respectively. The relationship between substrate concentrations and initial velocity for the thiolysis reaction were hyperbolic and gave K(infm) values for acetoacetyl-CoA and CoA of 42 and 56 (mu)M, respectively. The maximum velocity in the condensation direction was approximately 10% of that of the thiolysis reaction. With highly purified preparations of the enzyme, a value of approximately 1 mM was determined for the apparent K(infm) for acetyl-CoA. However, with partially purified enzyme preparations or when N-ethylmaleimide was included in reaction mixtures the apparent K(infm) for acetyl-CoA was close to 0.3 mM. In the condensation direction, CoA was a potent linear competitive inhibitor with an inhibition constant of 11 (mu)M. The much higher affinity of the enzyme for the product CoA than the substrate acetyl-CoA could have significance in view of metabolic differences between bacteroid and free-living cells of CC 1192. We propose that in free-living CC 1192 cells, the acetyl-CoA/CoA ratio reaches a value that allows condensation activity of acetyl-CoA acetyltransferase, but that in CC 1192 bacteroids, the ratio is poised so that the formation of acetoacetyl-CoA is not favored.

Journal Article↗
PubMed1996

Enzymes of Poly-(beta)-Hydroxybutyrate Metabolism in Soybean and Chickpea Bacteroids.

The enzymatic capacity for metabolism of poly-(beta)-hydroxybutyrate (PHB) has been examined in nitrogen-fixing symbioses of soybean (Glycine max L.) plants, which may accumulate substantial amounts of PHB, and chickpea (Cicer arietinum L.) plants, which contain little or no PHB. In the free-living state, both Bradyrhizobium japonicum CB 1809 and Rhizobium sp. (Cicer) CC 1192, which form nodules on soybean and chickpea plants, respectively, produced substantial amounts of PHB. To obtain information on why chickpea bacteroids do not accumulate PHB, the specific activities of enzymes of PHB metabolism (3-ketothiolase, acetoacetyl-coenzyme A reductase, PHB depolymerase, and 3-hydroxybutyrate dehydrogenase), the tricarboxylic acid cycle (malate dehydrogenase, citrate synthase, and isocitrate dehydrogenase), and related reactions (malic enzyme, pyruvate dehydrogenase, and glutamate:2-oxoglutarate transaminase) were compared in extracts from chickpea and soybean bacteroids and the respective free-living bacteria. Significant differences were noted between soybean and chickpea bacteroids and between the bacteroid and free-living forms of Rhizobium sp. (Cicer) CC 1192, with respect to the capacity for some of these reactions. It is suggested that a greater potential for oxidizing malate to oxaloacetate in chickpea bacteroids may be a factor that favors the utilization of acetyl-coenzyme A in the tricarboxylic acid cycle over PHB synthesis.

Journal Article↗
PubMed1994

Back to the future: sweatshop conditions on the Mexico-U.S. border. I. Community health impact of maquiladora industrial activity.

Present working conditions in one of the most active areas of the maquiladora system along the Mexico-U.S. border are reminiscent of nineteenth-century U.S. sweatshops. This conclusion was reached after evaluating two separate but interrelated surveys among Mexican nationals living near the Mexico-U.S. border, one of community leaders (Paper I), and one of workers in maquiladora enterprises in the towns of Matamoros and Reynosa, Mexico (Paper II). Paper I evaluates the results of the community leaders' survey. Criteria for selection of the leaders were: level of responsibility in the community; knowledge of the industry in the region, and length of residence in the area (more than 3 years). Representatives from government, maquiladora industry management, labor union leadership, labor union activists, and community improvement activists were interviewed. Structured questionnaires with opportunities for open-ended answers were used by trained Spanish speaking interviewers. The questions covered community demographics, health care structures, governance of the region, knowledge of working conditions, and knowledge of environmental impact on the region and the community. Community leaders were ambivalent on the purported benefits of the development of these types of industries in their communities. A substantial majority (21 of 25) thought that the maquiladoras brought few positive developments, other than creating jobs. Serious concerns about overextending weak social infrastructures and about environmental deterioration were voiced. Immediate (preventive) measures appear necessary to develop community infrastructures and to protect environmental health.

Community Health Services↗
PubMed1994

Kinetic properties of NAD-dependent glyceraldehyde-3-phosphate dehydrogenase from the host fraction of soybean root nodules.

The kinetic mechanism of NAD-dependent glyceraldehyde-3-phosphate dehydrogenase [D-glyceraldehyde-3-phosphate:NAD+ oxidoreductase (phosphorylating), EC 1.2.1.12] from the host cytosolic fraction of soybean (Glycine max L. Merr. cv. Williams) root nodules has been investigated by steady-state initial velocity studies and inhibition studies with products and product analogs. The results were consistent with the enzyme having a bi-uni-uni-uni ping-pong mechanism in which NAD+ and phosphate interacted sequentially with the enzyme, followed in turn by the release of 1,3-bisphosphoglycerate, the addition of D-glyceraldehyde-3-phosphate, and the release of NADH. At pH 7.2, NAD+ bound to the enzyme in a rapid-equilibrium fashion, whereas at pH 8.8 there was rapid-equilibrium addition of both NAD+ and phosphate to the enzyme. NADH was a strong competitive inhibitor with respect to NAD+ and phosphate. The enzyme was very labile, especially above pH 8, but the rate of loss of activity was considerably reduced in the presence of NAD+ and phosphate. The possible role of these properties in the regulation of NAD-dependent glyceraldehyde-3-phosphate dehydrogenase in the host cytosol of soybean nodules is discussed.

Adenosine Monophosphate↗
PubMed1991

Isoenzymes of glucose 6-phosphate dehydrogenase from the plant fraction of soybean nodules.

Two isoenzymes of glucose 6-phosphate dehydrogenase (EC 1.1.1.49) have been separated from the plant fraction of soybean (Glycine max L. Merr. cv Williams) nodules by a procedure involving (NH(4))(2)SO(4) gradient fractionation, gel chromatography, chromatofocusing, and affinity chromatography. The isoenzymes, which have been termed glucose 6-phosphate dehydrogenases I and II, were specific for NADP(+) and glucose 6-phosphate and had optimum activity at pH 8.5 and pH 8.1, respectively. Both isoenzymes were labile in the absence of NADP(+). The apparent molecular weight of glucose 6-phosphate dehydrogenases I and II at pH 8.3 was estimated by gel chromatography to be approximately 110,000 in the absence of NADP(+) and double this size in the presence of NADP(+). The apparent molecular weight did not increase when glucose 6-phosphate was added with NADP(+) at pH 8.3. Both isoenzymes had very similar kinetic properties, displaying positive cooperativity in their interaction with NADP(+) and negative cooperativity with glucose 6-phosphate. The isoenzymes had half-maximal activity at approximately 10 micromolar NADP(+) and 70 to 100 micromolar glucose 6-phosphate. NADPH was a potent inhibitor of both of the soybean nodule glucose 6-phosphate dehydrogenases.

Journal Article↗