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Biomedical subjects

N Garber

Publications and source records attributed to N Garber.

At least 19 recordsLinked to original sources

On the specificity of the D-galactose-binding lectin (PA-I) of Pseudomonas aeruginosa and its strong binding to hydrophobic derivatives of D-galactose and thiogalactose.

The D-galactose-binding lectin (PA-I) from the bacterium Pseudomonas aeruginosa, isolated by affinity chromatography on Sepharose, was examined for its relative affinities for simple sugars and their derivatives using equilibrium dialysis and hemagglutination inhibition tests. The lectin, which was found to bind 0.68 mol of D-galactose per subunit of 12.8 kDa, exhibited an association constant (Ka) of 3.4 x 10(4) M-1 for D-galactose and higher affinities for hydrophobic and thio derivatives of D-galactose (with highest affinity for the hydrophobic thio derivatives). alpha-Methyl-galactoside was a stronger inhibitor than the beta-methyl derivative and alpha-lactose was a weak inhibitor but the hydrophobic phenylated derivatives of the beta-configuration of D-galactose were more potent inhibitors than the respective alpha-galactosides.

Galactose

Rett syndrome: a longitudinal developmental case report.

Rett syndrome is a recently described progressive neurological disorder of unknown etiology occurring only in females, causing severe to profound mental retardation and characterized by loss of purposeful hand use and stereotypic hand movements. The present study examined development in five areas: gross motor skills, fine motor skills, self-help skills, communication, and cognition. Results indicated a general stagnation in all developmental areas beginning at approximately 15 months. No skills progressed beyond the 2-year level; this, despite several years of intensive, interdisciplinary intervention. Cognitive and communication skills regressed, then stabilized for several years, and subsequently began further regression. Gross motor and self-help skills appear to be areas of relative strength.

Activities of Daily Living

Microbial lectin cofunction with lytic activities as a model for a general basic lectin role.

Lectins are ubiquitous proteins, which exhibit a specific and reversible sugar-binding activity. They react with glycosylated macromolecules and cells and may coaggragate them and lead to their lysis or alterations. Various lectin biological effects are well known, but their basic biological function is considered as yet unknown. In the present review, an experimental evidence and theoretical considerations are forwarded for supporting our suggestion that the general basic lectin or lectinoid (lectin-like protein) function in microorganisms, plants and animals is a cofunction enabling the activities of key lytic enzymes (lysins: glycosidases, proteases, esterases, phosphatases, hemolysin, etc.). The lectin service is: homing onto glycosylated receptors, anchoring to them and induction of cooperative conformational effects which enable their counterpart lysin activity on exogenous or endogenous target molecules and cells. The 'lectin-lysin' pair may reside in the same molecule, or in linked subunits. It may also be formed by cofunction of two separate entities originating from one or two (homogenous or heterogenous) cell sources. The lectin and lysin may be free or cell-bound components located intra or extracellularly. The final result of their cofunction is practically irreversible; either cell and macro-molecule lysis for nutrition, homeostasis and protection or cell alteration, reorganization and new productivity. Our suggestion emphasizes the prominent analogy of lectins to lytic enzyme positioning sites (LEPS), immunoglobulins and polypeptide hormones. The lectin analogy to LEPS and immunoglobulins is exhibited in the lectin-dependent cell and macromolecule lysis for nutritional and homeostatic purposes or for protection, respectively. The hormone-like lectin activity is exhibited in the lectin-dependent cell alterations. In addition to similar functions and effects, the analogy also includes the properties and behavior of these proteins. The suggested hypothesis is based on experimental evidence from microorganisms, plants and animals. It envisions the lectin and lectinoid function in cell attacks on glycosylated molecules or cells, cell-substratum and cell-cell interactions (fusion, invasion, etc.), cell transformation and formation of special structures. All of them according to a developmental program, or special (especially unfavourable) environmental conditions. The lectin resistance to proteolysis and unfavourable pH or temperature is in accord with the suggested hypothesis.

Animals

Surface haemagglutinating activity of Pseudomonas aeruginosa.

Intact cells of several strains of Pseudomonas aeruginosa agglutinate papain-treated human erythrocytes. The agglutinating activity appears to reside in the surface layers of the bacterium-Pseudomonas surface haemagglutinin. This activity does not correlate with the existence of the internal PA-I and PA-II lectins, the presence of fimbriae or adherence to human buccal epithelial cells. Disruption of the bacterial cells by sonication abolishes their haemagglutinating activity. The intact cells of P. aeruginosa are also able to agglutinate rabbit, chicken, dog, guinea pig and sheep erythrocytes. This activity is generally higher with papain-treated erythrocytes, except those of rabbit in which lower haemagglutinating activity is observed after papain treatment. Optimal conditions for the haemagglutination are 37 degrees C and pH 6-7. Simple sugars do not inhibit, while fetuin and hydrophobic amino acids inhibit this activity. Exposure of the bacterial cells to proteolytic enzymes, EDTA or denaturating conditions abolish the haemagglutinating activity. These results indicate that the surface haemagglutinin is a protein which agglutinates red blood cells via hydrophobic interactions.

Amino Acids

Intractable postphlebitic ulceration of the leg.

A new regimen for the successful treatment of intractable postphlebitic ulceration of the leg is described. It is based on preliminary culture of organisms in the ulcers followed by sensitivity tests to ascertain the appropriate antibiotics or antibacterials to be used. Patients with Pseudomonas infection are hospitalized and receive: intramuscular injections of amikacin sulphate 500 mg twice daily for 7 days; a once-daily spraying of antibiotic powder on the ulcer for 7 days; and a topical gentian violet regimen once daily for a further 2 days to encourage adhesion of a dressing to the ulcer bed. After discharge the patients are treated in the consulting rooms. Ulcers without Pseudomonas infection but from which organisms have been cultured are treated in the consulting rooms with drugs indicated by the results of sensitivity tests, and topical gentian violet. Patients from whom organisms have not been cultured are treated with co-trimoxazole and topical gentian violet. Patients are taught correct bandaging of the calf with a 150 mm wide crêpe bandage and a Rowden Foote elastic bandage. Firm bandaging prevents calf oedema, the factor predisposing to ulceration. Patients are initially seen daily and then, as the dressing becomes adherent, at decreasing intervals until it is shed. Both bandages are worn until the affected tissues heal. The patient is then fitted with a below-knee heavy-duty elastic stocking.

Adult

Effects of growth phase and boiling of enteropathogenic Escherichia coli strains on their interaction with Pseudomonas aeruginosa lectins.

Escherichia coli strains from' serotypes O86, 0128 and O111 varied in their reactivity with Pseudomonas aeruginose lectins (PA-I with D-galactose specificity and PA-II which binds L-fucose, D-mannose, L-galactose and D-fructose). Generally, cells of O86 strains were agglutinated by PA-I, but not by PA-II, and those of O128 serotype were agglutinated by PA-II, and not by PA-I. Adsorption tests showed that cells of E. coli O86 strains adsorb PA-I to a greater extent than PA-II, while most E. coli O128 strains adsorbed higher amounts of PA-II. Cells of E. coli O111B4 which were not agglutinated by either Pseudomonas lectin could still adsorb both. Boiling of O86 and O128 cells frequently enhanced their agglutinability as well as their lectin adsorption capacity. The agglutinability enhancement was somewhat more prominent in boiled stationary phase cells than in log phase cells probably due to late synthesis of the O antigen components concomitantly with the heat-sensitive components (K antigens) which masked them. PA-I agglutinating activity was inhibited by the lipopolysaccharide (LPS) extracted from E. coli O86 cells, while PA-II was inhibited by the LPS extracted from E. coli O128 cells. These findings indicate that the receptors to the Pseudomonas lectins probably reside in the terminal part of the O-specific-polysaccharide of the LPSs of these bacteria.

Carbohydrate Conformation

Mannose-binding hemagglutinins in extracts of Pseudomonas aeruginosa.

Mannose-binding hemagglutinins were found in the extracts of a pyocyanin-forming Pseudomonas aeruginosa, which contain galactose-specific hemagglutinins. They were purified simultaneously with the latter proteins by heating to 70 degrees C, precipitating with ammonium sulfate, application to a Sepharose 4B column, and elution from it by 0.05 M mannose. The mannose-specific hemagglutinins were shown to be similar to the galactophilic ones in (a) being glycoproteins of very low molecular weight (about 11 000 by SDS gel electrophoresis), (b) their tendency to aggregate, and (c) their ability to effect stronger agglutination of erythrocytes treated with papain than of untreated ones. They were found to resemble them also in their reaction with simple sugars and interactions with divalent cations, which are essential for their activity. In these properties, as well as in their relative resistance to heat and to proteolytic enzymes, these two types of bacterial hemagglutinins are like most of the plant, contrasted with the animal, hemagglutinins. The reactions with mannose and mannose-bearing compounds (yeast mannan, horseradish peroxidase (EC 1.11.1.7), and serum globulins), which are not shared with the galactophilic Pseudomonas hemagglutinins, indicate a relationship of the mannose-binding protein of Pseudomonas to the plant lectin concanavalin A. The mannose-binding hemagglutinins do not exhibit identical cell-agglutinating spectra owing to difference in profiles of sugar specificity and relative affinity to mannose derivatives compared with free mannose.

Agglutinins

OSHA regulations: how they relate to ophthalmic practice.

The OSHA regulations, which took effect March 6, 1992, require that all employees be trained in infection control practices when they are hired, their job description changes, or the standards for universal precautions are revised. An explanation, provided to inform employees where a copy of the OSHA standard can be reviewed should be available at each clinical and surgical site, and OSHA regulation definitions must also be posted. The OSHA regulation applies to any clinical, housekeeping, or administrative staff that has any potential risk of exposure to blood or other potentially infectious substances.

Humans

Health promotion and disease prevention in ophthalmology.

There is a new trend in the US government's perception regarding health care today. It involves an increased awareness of how disease can be prevented and health promoted. The US government is supporting this concept with its Healthy People 2000 project. Specific pediatric concerns about health promotion and disease prevention in ophthalmology include amblyopia and strabismus, ophthalmia neonatorum, ocular trauma, radiation injury, xerophthalmia, herpes simplex, herpes zoster, infections and metabolic and genetic disorders. Adult health promotion/disease prevention priorities include glaucoma; trauma; diabetic retinopathy; corneal problems; iatrogenic infections; exposure keratitis; ocular toxicity from drugs, chemicals, and the environment; visual loss from neglect; and those mentioned in the pediatric area.

Academies and Institutes

The Bright Eyes Project: a 20-year effort to prevent blindness.

The Bright Eyes Project is a unique collaboration between medicine, public government, and a non-profit society. The project was prompted by concern that there was a high prevalence of undetected or untreated eye problems in the elderly. The objective was to detect ocular pathology, especially in those patients not currently receiving eye care. The project succeeded in providing a mechanism for free full ophthalmic examinations to the elderly at risk. In addition, the vast numbers seen in the project provide valuable statistics on common eye pathology in the individuals over 55 years of age.

Blindness

Calculating combined prism for spectacle prescriptions.

1. Combined prisms are required when correction incorporates vertical and horizontal strengths in one lens. 2. Calculations of the resultant prism power requires diagramming the vertical and horizontal vectors and drawing the resultant diagonal vector. The power is either derived from the Pythagorean Theorem or measured on graph paper. 3. The resultant prism base direction or axis designation is calculated from an equation or measured directly off the diagram with a protractor.

Equipment Design