Levels of aqueous humor trace elements in patients with open-angle glaucoma.

PURPOSE: Trace elements might play a role in the complex multifactorial pathogenesis of open-angle glaucoma. The aim of this study was to analyze concentrations of trace elements in aqueous humor samples of patients with primary open-angle glaucoma (POAG) and pseudoexfoliation glaucoma (PEXG). PATIENTS AND METHODS: Thirty-three aqueous humor samples were obtained from patients undergoing cataract surgery: 12 patients with POAG (age 65.3±10.50, female 8, male 4), 10 patients with PEXG (age 65.9±11.27, female 6, male 4) and 11 patients without glaucoma (age 69.5±13.70, female 7, male 4) serving as controls. Aqueous humor levels of cadmium, iron, manganese, cobalt, copper and zinc were measured by Flow-Injection-Inductively-Coupled-Plasma-Mass-Spectrometry (FI-ICP-MS). RESULTS: From the statistical evaluation, we observed that patients with POAG had significantly higher aqueous humor levels of zinc (p=0.006) compared to controls. Increased aqueous humor levels of zinc were also observed in patients with PEXG in relation to control (p=0.0006). For iron we observed a significantly reduction in PEXG compared to control (p=0.002) and a significant difference between POAG and PEXG (p=0.0091). No significant differences were observed in aqueous humor levels of manganese, cobalt, copper, cadmium between glaucoma and control patients. No differences were seen for iron (POAG vs. controls). Analysis of trace element ratios was added. CONCLUSION: Significant differences in aqueous humor levels of zinc and iron between glaucoma and control patients support the hypothesis that these trace elements are involved in the pathogenesis of open-angle glaucoma.

Dynamic fracture of inorganic glasses by hard spherical and conical projectiles.

In this article, high-speed photographic investigations of the dynamic crack initiation and propagation in several inorganic glasses by the impact of small spherical and conical projectiles are described. These were carried out at speeds of up to approximately 2×10(6) frames s(-1). The glasses were fused silica, 'Pyrex' (a borosilicate glass), soda lime and B(2)O(3). The projectiles were 0.8-2 mm diameter spheres of steel, glass, sapphire and tungsten carbide, and their velocities were up to 340 m s(-1). In fused silica and Pyrex, spherical projectiles' impact produced Hertzian cone cracks travelling at terminal crack velocities, whereas in soda-lime glass fast splinter cracks were generated. No crack bifurcation was observed, which has been explained by the nature of the stress intensity factor of the particle-impact-generated cracks, which leads to a stable crack growth. Crack bifurcation was, however, observed in thermally tempered glass; this bifurcation has been explained by the tensile residual stress and the associated unstable crack growth. A new explanation has been proposed for the decrease of the included angle of the Hertzian cone cracks with increasing impact velocity. B(2)O(3) glass showed dynamic compaction and plasticity owing to impact with steel spheres. Other observations, such as total contact time, crack lengths and response to oblique impacts, have also been explained.

Evaluation of plasma trace element and mineral status in children and adolescents with phenylketonuria using data from inductively-coupled-plasma atomic emission and mass spectrometric analysis.

BACKGROUND: Phenylketonuria (PKU) is caused by a severe phenylalanine hydroxylase deficiency; the mainstay of treatment is a low-phenylalanine diet. A diet which is so restrictive is associated with a risk of nutritional deficiencies. We investigated plasma concentrations for 46 elements, including minerals and trace elements. METHODS: We enrolled 20 children and adolescents with PKU and 20 matched controls. Multi-elementary quantification was carried out by solution-based inductively coupled plasma atomic emission spectroscopy (ICP-AES) and ICP mass spectrometry (ICP-MS). RESULTS: With the exception of manganese and aluminium, no significant differences were found for element levels between PKU patients and controls. As a trend, manganese levels were lower in PKU patients than in control subjects (p < 0.05) but were within the reference range. There was a positive linear relationship between manganese and tyrosine levels in subjects with PKU (r(2) = 0.2295, p < 0.05). If detectable, potentially toxic elements were only identified in ultra-trace quantities in plasma samples of either group; aluminium levels were found to be slightly higher in PKU subjects than in controls (p < 0.01). CONCLUSION: The combination of ICP-AES and ICP-MS data is a useful diagnostic tool for element quantification at a high analytical rate and for monitoring bio-element status, e.g. in patients on a restrictive diet.

Plasma copper and bone mineral density in osteopenia: an indicator of bone mineral density in osteopenic females.

Copper concentrations in blood plasma have been determined in 25 osteopenic females using inductively coupled plasma-mass spectrometry. A high degree of correlations has been demonstrated between the copper concentrations in plasma and the bone mineral density of the lumbar spine as measured using dual energy X-ray absorptiometry and quantitative computerized tomography. Results clearly indicate the involvement of copper in bone health and osteopenia. It is further suggested that plasma copper might be useful as a cheap and simple method indicative of bone mineral density in osteopenic postmenopausal females.

Inpatient interdisciplinary rehabilitation after total hip arthroplasty surgery: a comparison of revision and primary total hip arthroplasty.

OBJECTIVES: To describe outcomes of revision total hip arthroplasty (THA) patients who underwent interdisciplinary inpatient rehabilitation, and to compare them with primary THA patients. DESIGN: Descriptive and case-control study. SETTING: Forty-bed, community-based, freestanding rehabilitation hospital. PATIENTS: Thirty-nine revision THA subjects, gender- and age-matched with 39 primary THA controls. INTERVENTION: Inpatient interdisciplinary rehabilitation. MAIN OUTCOME MEASURES: FIM instrument, length of stay, hospital charges, and disposition location. RESULTS: The average revision THA patient stayed 10.5 days, improved from an admission FIM score of 89 to a discharge FIM score of 110, and incurred a hospital charge of $10,600. Of the revision THA patients, 98% were discharged home, and orthopedic-related complications were uncommon. No significant differences existed between revision and primary THA patients in any outcome measures. A trend toward higher rehabilitation charges ($12,400 vs $9500, p =.07) was found in revision THA patients who wore a hip orthosis. Otherwise, no differences were found in outcome measures based on the type of revision surgery, the presence of weight-bearing restrictions, or the presence of orthopedic complications. CONCLUSIONS: THA patients selected for inpatient rehabilitation have favorable short-term functional outcomes. The type of THA (primary vs revision) is not an independent differentiating factor.

Structure and sites of phosphorylation of 14-3-3 protein: role in coordinating signal transduction pathways.

The 14-3-3 family are homo- and heterodimeric proteins whose biological role has been unclear for some time, although they are now gaining acceptance as a novel type of 'adaptor' protein that modulates interactions between components of signal transduction pathways, rather than by direct activation or inhibition. It is becoming apparent that phosphorylation of the binding partner and possibly also the 14-3-3 proteins may regulate these interactions. 14-3-3 isoforms interact with a novel phosphoserine (Sp) motif on many proteins, RSX1,2SpXP. The two isoforms that interact with Raf-1 are phosphorylated in vivo on Ser185 in a consensus sequence motif for proline-directed kinases. The crystal structure of 14-3-3 indicates that this phosphorylation could regulate interaction of 14-3-3 with its target proteins. We have now identified a number of additional phosphorylation sites on distinct mammalian and yeast isoforms.

Charged photoparticle production in tissue during radiotherapy.

Photon-induced proton and alpha particle production in tissue is estimated for the photon energy range from 3 to 28 MeV, using the authors' previously established methods. It is shown that charged particle emission exceeds neutron emission for energies greater than 11 MeV by a factor that reaches a maximum of 7.0 at 17 MeV. Due to uncertainties in the source data this maximum value should be regarded as indicative only. Above 17 MeV the neutron yield rises sharply and the ratio of charged particle emission to neutron emission declines to values of 3.0 and 1.7 at 20 and 28 MeV, respectively.

Nuclear analytical methods in calcified tissue research.

Various nuclear analytical methods have been developed and applied to determine the elemental composition of calcified tissues (teeth and bones). Fluorine was determined by prompt gamma-activation analysis through the 19F(rho, alpha, gamma)16O reaction. Carbon was measured by activation analysis with 3He ions, and the technique of proton-induced x-ray emission (PIXE) was applied to simultaneously determine calcium, phosphorus, and trace elements in well-documented teeth. Dental hard tissues (enamel, dentine, cementum, and their junctions) and different parts of the same tissue were examined separately. With the use of a proton microprobe, we measured the surface distribution of fluorine and other elements on and around carious lesions on the enamel. The depth profiles of fluorine, and other elements were also measured right up to the amelodentin junction. We discuss the development of various nuclear techniques and their applications, mainly in the field of dental health and to some extent in the study of the role of lead in mental retardation. We do not mention other important areas of calcified tissue research where these techniques could play an important role (e.g., in accurate and nondestructive measurements of calcium, phosphorus, and other elements in small bone biopsies taken from patients with metabolic bone disorders). No suitable chemical method appears to be available that can provide accurate assessment of calcium, phosphorus, and other trace elements in small bone biopsies. Moreover, the nondestructive nature of the nuclear methods has an extra advantage in that the bone samples, which are normally rather small in quantity, subsequently can be used for histologic examination.

Expression of a glycosylphosphatidylinositol-anchored Trypanosoma brucei transferrin-binding protein complex in insect cells.

The expression site-associated gene ESAG 6 was previously implicated in transferrin binding in the protozoan parasite Trypanosoma brucei. ESAG 6 and the closely related ESAG 7 of T. brucei strain AnTat1.3 have now been expressed in insect cells using the baculovirus expression system. Expression of ESAG 6 alone in insect cells gives rise to a glycosylated protein of approximately 52 kDa, which is cell surface-associated through a glycosylphosphatidylinositol anchor at its C terminus. The ESAG 7 product of about 42 kDa is also glycosylated, but lacks the glycosylphosphatidylinositol modification, and is located intracellularly. No transferrin-binding activity is observed when either ESAG is expressed independently. However, their expression results in a cell surface complex of ESAG 6 and 7 products that specifically binds transferrin. This shows that both ESAG 6 and 7 products are necessary and sufficient for binding to transferrin.

ESAG 6 and 7 products of Trypanosoma brucei form a transferrin binding protein complex.

In Trypanosoma brucei, the gene for the expressed variant surface glycoprotein (VSG) is preceded by a series of open reading frames designated expression site associated genes (ESAGs), which together with the VSG gene form a polycistronic transcription unit. It is shown that the products derived from two ESAGs (ESAG 6 and 7 in the nomenclature of Pays, E., et al. Cell 57, 835-845 (1989)) form a complex, which binds transferrin with high affinity. Transferrin affinity chromatography yields heterodimers or higher order heteroligomers composed of the products of ESAG 6 and ESAG 7. The former is a heterogeneously glycosylated protein of 50 to 60 kDa modified by a glycosylphosphatidylinositol membrane anchor at the COOH-terminus, while the latter is the previously identified 42 kDa glycoprotein carrying an unmodified COOH-terminus (Schell, D., et al. EMBO J. 10, 1061-1066 (1991) and Schell, D., et al. EMBO J. 12, 2990 (1993)). When isolated from trypanosomes grown in rodents, the complex is in part free and in part associated with transferrin. Also, the complex is present both in the membrane fraction and the soluble fraction of cell lysates. As shown by immunoelectron microscopy, both transferrin and ESAG 6/7-derived proteins can be demonstrated in the lumen of the flagellar pocket, an invagination of the plasma membrane serving as the sole site for endocytotic uptake of macromolecular nutrients. Weak labeling is also obtained on the flagellar pocket membrane and in intracellular vesicles. The possibility that the binding protein complex serves as a receptor for the uptake of transferrin in T. brucei is discussed.

Structure and function of GPI-anchored surface proteins of Trypanosoma brucei.

While proteins modified at their COOH-terminal end by a glycosylphosphatidylinositol (GPI) membrane anchor have been found as minor components in many eukaryotic cells, they dominate surface constituents of several parasitic protozoa. In this article, GPI-anchored proteins of Trypanosoma brucei are discussed.

Structure and function of GPI-anchored surface proteins of Trypanosoma brucei

While proteins modified at their COOH-terminal end by a glycosylphosphatidylinositol (GPI) membrane anchor have been found as minor components in many eukaryotic cells, they dominate surface constituents of several parasitic protozoa. In this article, GPI-anchored proteins of Trypanosoma brucei are discussed

Invariant surface proteins in bloodstream forms of Trypanosoma brucei.

Antigenic variation of the glycoprotein forming the coat of African trypanosomes has been a dominant field of investigation for many years. The extravagant potential of these parasites to change their surface coat has destroyed hopes for a vaccine based on the variant surface glycoprotein. Recently, there has been a rising interest in the characterization of surface proteins that are not subject to antigenic variation. In this review, Peter Overath, Maliha Chaudhri, Dietmar Steverding and Karl Ziegelbauer summarize the present evidence for the occurrence, cellular localization and function of invariant surface proteins in Trypanosoma brucei.

A putative anaerobic coproporphyrinogen III oxidase in Rhodobacter sphaeroides. II. Analysis of a region of the genome encoding hemF and the puc operon.

The puc operon of Rhodobacter sphaeroides encoding polypeptides of the major light-harvesting complex, LH2, has been found to be linked to hemF, a gene encoding a putative anaerobic coproporphyrinogen III oxidase. The puc-hemF region of the R. sphaeroides genome has been investigated by insertional mutagenesis, complementation analysis of these insertional mutants and DNA sequencing. A third gene, designated pucC, has been found immediately downstream of pucA and has been shown to be essential for LH2 expression. pucC is cotranscribed with pucB and pucA; however, hemF and the pucBAC operon were found not to be transcriptionally linked. Ultrastructural studies indicated that the morphology of the intracytoplasmic membrane may depend upon expression of pucC as well as pucBA.

Production of neutrons from water, polyethylene, tissue equivalent material and CR-39 irradiated with 2.5-30 MeV photons.

Photoneutron yields from water, polyethylene, tissue substitute and CR-39 have been calculated for the photon energy range of 2 to 30 MeV, using a previously established method and photoneutron production data on hydrogen, carbon, nitrogen and oxygen. The rarer isotopes of the constituent elements of these compounds, namely 2H, 13C, 15N, 17O and 18O, have been taken into account and neutrons are shown to be produced for photon energies above 2.2 MeV, the (gamma, n) threshold for 2H. The data are useful for estimating neutron production in materials located in the vicinity of a megavoltage radiotherapy beam. Substances such as those considered here are often used as filtration, phantom or scattering material and as components of neutron dosimetry detectors. Photoneutrons produced in such materials may need to be taken into consideration when carrying out neutron dosimetry in the presence of photons in this energy range, especially when the neutron flux is several orders of magnitude less than that of the photons.

Effect of different pump mechanisms on transfusion of blood.

Sometimes infusion pumps are used to deliver whole blood to patients. However, in doing so there is a potential for damage to red cells from mechanical stresses in the pump, resulting in haemolysis. In order to investigate the degree of haemolysis caused by different pumps and therefore their suitability for whole blood infusion, we compared the performances of commonly used volumetric pumps (AVI 400; IVAC 560; IVAC 631 and IMED 927) with different pumping mechanisms. Our results show that the maximum haemolysis (3.9 mg/100g) was caused by the IVAC 560 and the least (1.08 mg/100g) by the AVI 400.

Amorphisation of MgO single crystal specimens prepared by ion milling for transmission electron microscopy studies.

Single crystal MgO specimens having low load Vickers indentations were thinned in an ion milling machine employing a single ion gun, and their characteristics were investigated with optical microscopy and high voltage electron microscopy (HVEM). It was found that the state of cleanliness of the specimen chamber of the ion milling machine had a very marked influence on the quality of the thinned specimens. If the specimen chamber was not well cleaned before ion milling a fresh specimen, the latter tended to show amorphisation due to the deposition on the specimen of the debris left in the chamber from the previously ion-milled specimens. Such observations were made from MgO specimens ion milled in several different types of commercial ion milling machine employing a single gun. It is proposed that to obtain good-quality ion milled TEM specimens, it is important to clean the specimen chamber thoroughly prior to milling.

Nuclear analytical methods for trace element studies in calcified tissues.

Various nuclear analytical methods have been developed and applied to determine the elemental composition of calcified tissues (teeth and bones). Fluorine was determined by prompt gamma activation analysis through the 19F(p, alpha gamma) 16O reaction. Carbon was measured by activation analysis with He-3 ions, and the technique of Proton-Induced X-ray Emission (PIXE) was applied to simultaneously determine Ca, P, and trace elements in well-documented teeth. Dental hard tissues: enamel, dentine, cementum, and their junctions, as well as different parts of the same tissue, were examined separately. Furthermore, using a Proton Microprobe, we measured the surface distribution of F and other elements on and around carious lesions on the enamel. The depth profiles of F, and other elements, were also measured right up to the amelodentin junction.

Carbon determination in human teeth by activation with He-3 ions.

A nuclear analytical method, involving activation with 3He ions, was developed to determine carbon content in human teeth with well-documented histories. The tooth samples were irradiated with 2.7-MeV3He particles at 50 nA intensity, and the activity of 14O induced through the reaction 12C(3He, n)14O, determined by counting the 2.31-MeV gammas. Different dental hard tissues were studied separately. A solid piece of silver steel, the carbon content of which was accurately determined by chemical means, was used as the standard. The carbon content in different teeth varied from 4-7%. The overall experimental accuracy was better than 4.5%.