A review of rigid lens design.
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Editorial↗
Biomedical subjects
K Edwards
Publications and source records attributed to K Edwards.
Use of superficial femoropopliteal vein for suprainguinal arterial reconstruction in the presence of infection.
BACKGROUND: Conventional treatment of mycotic aneurysms or graft infections of the aortoiliac segment by in situ or extra-anatomic prosthetic reconstruction has a high mortality and morbidity rate, with a substantial risk of persistent graft infection. The use of autologous vein may reduce this. METHODS: Eleven patients with suprainguinal arterial infections including two with mycotic aortic aneurysms, four with aortic graft infections, four infected femorofemoral grafts and an infected axillofemoral graft were treated by debridement and in situ reconstruction with autologous superficial femoropopliteal vein. All patients received appropriate antibiotic therapy and were followed by regular postoperative duplex imaging. Preoperative femoral vein duplex imaging was performed in eight of the 11 patients. RESULTS: Ten of the 11 patients survived with a functioning graft and without limb loss or evidence of infection at 4-33 months. One patient died from myocardial infarction after operation. Three patients had minor swelling of one leg. Four patients required subsequent angioplasty of anastomotic stenoses detected by duplex surveillance. CONCLUSION: Superficial femoropopliteal vein is an excellent conduit for suprainguinal reconstruction in the presence of infection. Duplex imaging is useful for confirming the suitability of deep veins for use as a graft and for postoperative surveillance.
Aged↗
Service users and mental health nursing.
A better understanding of the views of service users has become increasingly relevant in providing mental health services and for the role of the mental health nurse in meeting users' needs. The four key issues that this research endeavoured to address were: (1) What are the views and perceived needs of users of mental health services in the context of the role that users see nurses fulfilling? (2) How do student nurses perceive their future role given the changes in nurse prepartion? (3) To what extent do the answers to the first two questions converge and/or diverge? (4) Recommend actions on ways in which mental health nurse training could be improved, in light of the findings of this research. Methodologically, both qualitative and quantitative data gathering approaches were used, the former for stage one in setting the agenda and the latter for stage two by means of questionnaires. The findings indicate that the key concerns for users are issues of choice, individuality, information and quality of care in terms of positive interpersonal relationships with those who have responsibilities for helping them and who are sensitive to their real needs. Users are not asking for any costly or extravagant therapies but support that is relevant to their needs and provided in a compassionate manner. The context of their lives and the degree to which users feel integrated into society is a prominent concern. These findings have implications for how mental health nurses are educated and trained and how on qualifying they function in practice. The findings throw into question whether mental health nursing can adapt to the desired changes that are being called for.
Humans↗
Repeatability of the Visual Manipulation Test.
BACKGROUND: The Getman-Henderson-Marcus Visual Manipulation Test (VMT) is a commonly used test of visualization with an objective scoring procedure. However, its repeatability has not been studied. PURPOSE: The purpose of this investigation was to assess the repeatability of the VMT in children in the second through fourth grades. METHOD: The VMT was administered to the children (n = 193; mean age, 8.72 years) from a middle class elementary school near Columbus, Ohio. One class from each grade (n = 56) was retested by the same optometrist within 1 month. Repeatability analysis included plotting the difference vs. the mean of the scores obtained at the initial test and retest. RESULTS: All the children were able to complete the test. Means and SD's were found to be 5.23+/-1.98 for second graders, 5.76+/-2.10 for third graders, and 6.95+/-2.30 for fourth graders. The mean difference between test and retest scores was close to zero. The 95% limits of agreement were found to be -4.5 to 5.2. CONCLUSION: No consistent learning effect seemed to be present upon retest. However, analysis revealed poor repeatability for the VMT. Therefore, the VMT should not be used to monitor progress with therapy.
Child↗
Efficacy, safety and immunogenicity of heptavalent pneumococcal conjugate vaccine in children. Northern California Kaiser Permanente Vaccine Study Center Group.
OBJECTIVE: To determine the efficacy, safety and immunogenicity of the heptavalent CRM197 pneumococcal conjugate vaccine against invasive disease caused by vaccine serotypes and to determine the effectiveness of this vaccine against clinical episodes of otitis media. METHODS: The Wyeth Lederle Heptavalent CRM197 (PCV) was given to infants at 2, 4, 6 and 12 to 15 months of age in a double blind trial; 37,868 children were randomly assigned 1:1 to receive either the pneumococcal conjugate vaccine or meningococcus type C CRM197 conjugate. The primary study outcome was invasive disease caused by vaccine serotype. Other outcomes included overall impact on invasive disease regardless of serotype, effectiveness against clinical otitis media visits and episodes, impact against frequent and severe otitis media and ventilatory tube placement. In addition the serotype-specific efficacy against otitis media was estimated in an analysis of spontaneously draining ears. RESULTS: In the interim analysis in August, 1998, 17 of the 17 cases of invasive disease caused by vaccine serotype in fully vaccinated children and 5 of 5 of partially vaccinated cases occurred in the control group for a vaccine efficacy of 100%. Blinded case ascertainment was continued until April, 1999. As of that time 40 fully vaccinated cases of invasive disease caused by vaccine serotype had been identified, all but 1 in controls for an efficacy of 97.4% (95% confidence interval, 82.7 to 99.9%), and 52 cases, all but 3 in controls in the intent-to-treat analysis for an efficacy of 93.9% (95% confidence interval, 79.6 to 98.5%). There was no evidence of any increase of disease caused by nonvaccine serotypes. Efficacy for otitis media against visits, episodes, frequent otitis and ventilatory tube placement was 8.9, 7.0, 9.3 and 20.1% with P < 0.04 for all. In the analysis of spontaneously draining ears, serotype-specific effectiveness was 66.7%. CONCLUSION: This heptavalent pneumococcal conjugate appears to be highly effective in preventing invasive disease in young children and to have a significant impact on otitis media.
Bacterial Vaccines↗
Use of clindamycin disks To detect macrolide resistance mediated by ermB and mefE in Streptococcus pneumoniae isolates from adults and children.
We studied 198 macrolide-resistant S. pneumoniae isolates obtained from adults and children to evaluate whether 2-microgram clindamycin disks can distinguish between isolates manifesting ermB- versus mefE-mediated resistance to clarithromycin and to determine the relative frequency with which each resistance mechanism occurred in these populations. The mefE gene was predominant among 109 isolates from children, occurring in 73.4% versus 50.6% of 89 isolates from adults. Three isolates (1.5%) did not amplify either gene. Among 125 mefE(+) isolates, the MIC of clarithromycin at which 90% of the isolates tested were inhibited, determined by Etest, was 32 microgram/ml versus >256 microgram/ml in 70 ermB(+) isolates. All ermB(+) isolates were highly resistant to clindamycin (MICs >256 microgram/ml), whereas all mefE(+) isolates were susceptible to clindamycin using the 2-microgram disk. Testing S. pneumoniae from the respiratory tract for susceptibility to clindamycin by agar disk diffusion is an easy and inexpensive method to estimate the frequency of resistance mediated by ermB in specific patient populations. Macrolide resistance mediated by ermB is usually of greater magnitude than that due to mefE. Clinical studies are needed to determine the significance of high- versus low-level macrolide resistance in S. pneumoniae.
Adult↗
Continuous wear contact lenses: have we been here before?
New developments in contact lens materials have led to the introduction of new lenses designed for up to 30 days of continuous wear. Will these lenses lead to safer and healthier overnight use of lenses?
Biocompatible Materials↗
Human responses to pain: a global perspective.
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Attitude to Health↗
A multi-step lipid mixing assay to model structural changes in cationic lipoplexes used for in vitro transfection.
Formation of liposome/polynucleotide complexes (lipoplexes) involves electrostatic interactions, which induce changes in liposome structure. The ability of these complexes to transfer DNA into cells is dependent on the physicochemical attributes of the complexes, therefore characterization of binding-induced changes in liposomes is critical for the development of lipid-based DNA delivery systems. To clarify the apparent lack of correlation between membrane fusion and in vitro transfection previously observed, we performed a multi-step lipid mixing assay to model the sequential steps involved in transfection. The roles of anion charge density, charge ratio and presence of salt on lipid mixing and liposome aggregation were investigated. The resonance-energy transfer method was used to monitor lipid mixing as cationic liposomes (DODAC/DOPE and DODAC/DOPC; 1:1 mole ratio) were combined with plasmid, oligonucleotides or Na(2)HPO(4). Cryo-transmission electron microscopy was performed to assess morphology. As plasmid or oligonucleotide concentration increased, lipid mixing and aggregation increased, but with Na(2)HPO(4) only aggregation occurred. NaCl (150 mM) reduced the extent of lipid mixing. Transfection studies suggest that the presence of salt during complexation had minimal effects on in vitro transfection. These data give new information about the effects of polynucleotide binding to cationic liposomes, illustrating the complicated nature of anion induced changes in liposome morphology and membrane behavior.
4-Chloro-7-nitrobenzofurazan↗
Incorporation of bacterial membrane proteins into liposomes: factors influencing protein reconstitution.
Meningococcal and gonococcal outer membrane proteins were reconstituted into liposomes using detergent-mediated dialysis. The detergents octyl glucopyranoside (OGP), sodium cholate and Empigen BB were compared with respect to efficiency of detergent removal and protein incorporation. The rate of OGP removal was greater than for cholate during dialysis. Isopycnic density gradient centrifugation studies showed that liposomes were not formed and hence no protein incorporation occurred during dialysis from an Empigen BB containing reconstitution mixture. Cholate-mediated reconstitution yielded proteoliposomes with only 75% of the protein associated with the vesicles whereas all of the protein was reconstituted into the lipid bilayer during OGP-mediated reconstitution. Essentially complete protein incorporation was achieved with an initial protein-to-lipid ratio of 0.01:1 (w/w) in the reconstitution mixture; however, at higher initial protein-to-lipid ratios (0.02:1) only 75% protein incorporation was achieved. Reconstituted proteoliposomes were observed as large (>300 nm), multilamellar structures using cryo-electron microscopy. Size reduction of these proteoliposomes by extrusion did not result in significant loss of protein or lipid. Extruded proteoliposomes were unilamellar vesicles with mean diameter of about 100 nm.
Bacterial Outer Membrane Proteins↗
Filamin is required for ring canal assembly and actin organization during Drosophila oogenesis.
The remodeling of the actin cytoskeleton is essential for cell migration, cell division, and cell morphogenesis. Actin-binding proteins play a pivotal role in reorganizing the actin cytoskeleton in response to signals exchanged between cells. In consequence, actin-binding proteins are increasingly a focus of investigations into effectors of cell signaling and the coordination of cellular behaviors within developmental processes. One of the first actin-binding proteins identified was filamin, or actin-binding protein 280 (ABP280). Filamin is required for cell migration (Cunningham et al. 1992), and mutations in human alpha-filamin (FLN1; Fox et al. 1998) are responsible for impaired migration of cerebral neurons and give rise to periventricular heterotopia, a disorder that leads to epilepsy and vascular disorders, as well as embryonic lethality. We report the identification and characterization of a mutation in Drosophila filamin, the homologue of human alpha-filamin. During oogenesis, filamin is concentrated in the ring canal structures that fortify arrested cleavage furrows and establish cytoplasmic bridges between cells of the germline. The major structural features common to other filamins are conserved in Drosophila filamin. Mutations in Drosophila filamin disrupt actin filament organization and compromise membrane integrity during oocyte development, resulting in female sterility. The genetic and molecular characterization of Drosophila filamin provides the first genetic model system for the analysis of filamin function and regulation during development.
Actins↗
Reconstituted phosphatidylserine synthase from Escherichia coli is activated by anionic phospholipids and micelle-forming amphiphiles.
The activity of phosphatidylserine (PS) synthase (CDP-1, 2-diacyl-sn-glycerol: l-serine O-phosphatidyltransferase, EC 2.7.8. 8) from Escherichia coli was studied after reconstitution with lipid vesicles of various compositions. PS synthase exhibited practically no activity in the absence of a detergent and with the substrate CDP-diacylglycerol (CDP-DAG) present only in the lipid vesicles. Inclusion of octylglucoside (OG) in the assay mixture increased the activity 20- to 1000-fold, the degree of activation depending on the lipid composition of the vesicles. Inclusion of additional CDP-DAG in the assay mixture increased the activity 5- to 25-fold. When the fraction of phosphatidylglycerol (PG) was increased from 15 to 100 mol% in the vesicles the activity increased 10-fold using the assay mixture containing OG. The highest activities were exhibited with the anionic lipids synthesized by E. coli, namely PG, diphosphatidylglycerol (DPG), and phosphatidic acid, while phosphatidylinositol gave a lower activity. Cryotransmission electron microscopy showed that transformation of the vesicles to micelles brings about an activation of the enzyme that is proportional to the degree of micellization. Thus, the activity of PS synthase is modulated by the lipid aggregate structure and by the fraction and type of anionic phospholipid in the aggregates. The increase in the activity caused by PG and DPG is physiologically relevant; it may be part of a regulatory mechanism that keeps the balance between phosphatidylethanolamine, and the sum of PG and DPG, nearly constant in wild-type E. coli cells.
CDPdiacylglycerol-Serine O-Phosphatidyltransferase↗
Characterization of permeability and morphological perturbations induced by nisin on phosphatidylcholine membranes.
Nisin is an antimicrobial peptide used as food preservative. To gain some insights into the hypothesis that its bactericidal activity is due to the perturbation of the lipid fraction of the bacterial plasmic membrane, we have investigated the effect of nisin on model phosphatidylcholine (PC) membranes. We show that nisin affects the PC membrane permeability, and this perturbation is modulated by the lipid composition. Nisin-induced leakage from PC vesicles is inhibited by the presence of cholesterol. This inhibition is associated with the formation of a liquid ordered phase in the presence of cholesterol, which most likely reduces nisin affinity for the membrane. Conversely, phosphatidylglycerol (PG), an anionic lipid, promotes nisin-induced leakage, and this promotion is associated with an increased affinity of the peptide for the bilayer because nisin is a cationic peptide. When the electrostatic interactions are encouraged by the presence of 70 mol% PG in PC, the inhibitory effect of cholesterol is not observed anymore. Nisin drastically modifies the morphology of the dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) multilamellar dispersion without causing a significant change in the gel-to-liquid crystalline phase transition of the lipid. The morphological changes are observed from (31)P and (2)H NMR and cryo-electron microscopy. From the NMR point of view, the interactions giving rise to a broad signal (quadrupolar interactions and chemical shift anisotropy for (2)H NMR and (31)P NMR, respectively) are partly averaged out in the presence of nisin. This phenomenon is interpreted by the formation of curved lipid planes that lead to the lipid lateral diffusion occurring in the intermediate motional regime. By cryo-electron microscopy, large amorphous aggregates containing small dense globular particles are observed for samples quenched from 25 and 50 degrees C. Long thread-like structures are also observed in the fluid phase. A structural description of DPPC/nisin complex, consistent with the experimental observation, is proposed. The presence of 30 mol% cholesterol in DPPC completely inhibits the morphological changes induced by nisin. Therefore, it is concluded that nisin can significantly perturb PC bilayers from both the permeability and the structural points of view, and these perturbations are modulated by the lipidic species in the bilayer.
Anti-Bacterial Agents↗
A simple laboratory method for inducing anger: a preliminary investigation.
To facilitate the experimental study of anger, we developed a simple laboratory method to induce anger. This anger induction (AI) is similar in format to the Velten Mood Induction Procedure for depression (VMIP-D), and involves reading descriptors of anger experience, recalling relevant personal memories, and evoking the mood suggested by the sentence/memory. We administered the AI and VMIP-D to 81 undergraduate men and women and collected mood ratings before, during, and after each mood induction. The AI exhibited good sensitivity and specificity in that it induced moderate to greater increases in anger (>1 SD change) in 68% of the sample, significant decreases in happiness, and minimal changes in other emotions. Mood responses to the AI and VMIP-D were influenced by gender and order of presentation. Uses and limitations of this method are discussed.
Adult↗
The reproducibility of videokeratoscope measurements as applied to the human cornea.
To be useful in contact lens fitting, the videokeratoscope (VK) must be able to provide the practitioner with credible data on the vertex radius and central topography, or 'shape, of the patient's cornea. For this purpose, it is desirable that the measured value of the former should be credible at the level of 0.05 mm. In order to examine the accuracy, repeatability and reproducibility of the corneal dimensions provided by the videokeratoscope, eight eyes were measured on four different EyeSys systems at four independent sites. The order of measurement was random at each site. This amounted to a balanced uniform-level precision experiment ('ring test') of the VK instruments as defined in International Standard ISO 5725. The resulting data were analysed using the statistical procedures given in this Standard to provide a formal statement of the measurement precision of the EyeSys VK system. Based on this study, the estimated measurement precision of the EyeSys videokeratoscope as applied to the latter principal meridian of the normal human cornea is: Vertex radius: repeatability standard deviation, S(R)=0.0805, reproducibility standard deviation, S(R)=0.1041. p value: repeatability standard deviation, S(r)=0.0473, reproducibility standard deviation, S(R)=0.0574. The estimated measurement precision for the steeper principal meridian is: Vertex radius: repeatability standard deviation, S(r)=0.0771; reproducibility standard deviation, S(R)=0.1015. p value: repeatability standard deviation, S(R)=0.0698; reproducibility standard deviation, S(R)=0.0749.
Journal Article↗
The EyeSys videokeratoscopic assessment of apical radius and p-value in the normal human cornea.
The EyeSys videokeratoscope was used to assess the corneal topography in 98 subjects. Scatterplots of distance squared versus radius squared were plotted for the near horizontal and near vertical principal meridians of the two eyes. The regression lines allowed calculation of the surface apical radius and the p-value. The group average apical radius was 7.93 mm (horizontal) and 7.78 mm (vertical). The group average p-value was 0.76 (horizontal) and 0.82 (vertical). Both apical radius and p-value were similar when comparing the two eyes for both the horizontal and the vertical meridians. The two meridians in a single eye, however, had different values for both apical radius and p-value. Male apical radii were longer than those of females but the p-values were the same. There is no apparent association between age and either apical radius or p-value for the subjects used in this study. The asphericity of the cornea does not show any apparent association with corneal curvature in this group of subjects.
Adult↗
Effect of pistachio nuts on serum lipid levels in patients with moderate hypercholesterolemia.
BACKGROUND: Elevated serum cholesterol levels play an important role in the development of coronary artery disease. Previous studies have suggested that nut consumption benefits lipid profile. Pistachio nuts are widely available, inexpensive and frequently consumed by the general population. OBJECTIVE: To determine whether substituting 20% of the daily caloric intake in the form of pistachio nuts will improve the lipid profiles of humans with primary, moderate hypercholesterolemia. DESIGN: Controlled, randomized crossover design. SETTING: Outpatient dietary modification, counseling and blood analysis. PATIENTS: Ten patients with moderate hypercholesterolemia. INTERVENTION: Three weeks of dietary modification with 20% caloric intake from pistachio nuts. MEASUREMENTS: Body weight, blood pressure, total cholesterol, LDL, HDL, and triglycerides were monitored. Lipid profiles were analyzed prior to, during and after dietary modification. RESULTS: After three weeks, there was a decrease in total cholesterol (p<0.04), an increase in HDL (p<0.09), a decrease in the total cholesterol/HDL ratio (p<0.01) and a decrease in the LDL/HDL ratio (p<0.02). Triglycerides and LDL levels decreased, but not significantly. Body weight and blood pressure remained constant throughout the study. CONCLUSIONS: Results suggest that eating pistachio nuts instead of other dietary fat calories can improve lipid profiles, thereby decreasing coronary risk. Further studies will be required to confirm these results and to determine the mechanism of this effect.
Adult↗