Perinatal mental health services for mothers from ethnic minority and migrant backgrounds

Perinatal mental health disorders are among the most common morbidities of the perinatal period with considerable adverse effects on mothers and their offspring. Members of ethnic minority groups, particularly those from migrant backgrounds, are at higher risk of developing mental illness with evidence of ongoing inequality in access to support. We will present an exploratory mixed-methods study scoping ethnic minority and migrant women's experiences accessing perinatal mental health services in the UK. Results showed how women perceived access to services as very challenging and how they experienced ‘suffering in silence', a ‘need for a safe space to talk and to be listened to', and a ‘need of finding other women like them'. We will complement these findings with the lessons learned from a related project, a three-site European study (ORAMMA) evaluating the feasibility of implementing an integrated perinatal care model for migrant mothers comprising maternity peer supporters (MPSs)-women from migrant backgrounds who had lived in the country for a longer time and were trained to support other migrant women during the childbearing continuum-. Results showed that MPSs supported migrant women accessing maternity care, overcoming language barriers, and advocating for them in their encounters with healthcare professionals. Besides, they provided emotional support and increased women's confidence, helping them overcome loneliness, encouraging them to build relationships with others and promoting bonding with the new baby. Bringing these two projects together, we will discuss how MPSs have the potential to help overcome barriers that immigrant women experience in seeking perinatal mental health and how the benefits of maternity peer supporters have the potential to reduce perinatal mental health risks amongst migrant mothers. Findings will point to the need for future research to evaluate the direct impacts of MPSs on immigrant's mother perinatal mental health.

Extended release of adenovirus from silica implants in vitro and in vivo

Despite promising preclinical results, the clinical benefits of cancer gene therapy have been modest heretofore. The main obstacle continues to be the level and persistence of gene delivery to sufficiently large areas of the tumor. One approach for overcoming this might entail extended local virus release. We studied the utility of silica gel monoliths for delivery of adenovirus to advanced orthotopic gastric and pancreatic cancer tumors. Initially, the biochemical properties of the silica-virus matrix were studied and nearly linear release as a function of time was detected. Virus stayed infective for weeks at +37 degrees C and months at +4 degrees C, which may facilitate storage and distribution. In vivo, extended release of functional replication deficient and also replication-competent, capsid-modified oncolytic viruses was seen. Treatment of mice with pancreatic cancer doubled their survival (P<0.001). Also, silica gel-based delivery slowed the development of antiadenovirus antibodies.

Comparison between sol-gel-derived anatase- and rutile-structured TiO2 coatings in soft-tissue environment

The bioactivity of the surface reactive TiO(2) coatings for medical implants can be locally modified by CO(2) laser processing to match with the properties of surrounding tissues. The TiO(2) coatings heat-treated at 500 degrees C exhibit in vitro bioactivity. With further CO(2) laser treatment they exhibit enhanced in vitro bioactivity. The aim of this in vivo study was to compare the performance of heat-treated anatase-structured TiO(2) coatings with preheat-treated and CO(2) laser-treated rutile-structured coatings in terms of their ability to attach soft connective tissues. The coatings were characterized with TF-XRD and AFM. TiO(2)-coated discs were implanted in rats. The samples were analyzed with routine histology, SEM-EDS, and TEM. In both groups, already at 3 days, soft connective tissues were in immediate contact with the surface. No thick crystalline CaP layer was detected by SEM-EDS, but a thin amorphous CaP layer was detected by XPS. No gap between the cell membrane and the coating could be observed in TEM pictures. No differences were observed between the anatase- and rutile-structured coatings in terms of tissue responses. Further studies are needed to verify if the tissues are adherent to the surface of the implant.

Biomimetic mineralization of partially bioresorbable glass fiber reinforced composite

The aim of this study was to investigate the biomimetic mineralization on the surface of a glass fiber reinforced composite with partially resorbable biopolymer matrix. The E-glass fibers were preimpregnated with a novel biopolymer of poly(hydroxyproline) amide, and further impregnated in the monomer system of bis-phenyl glycidyl dimethacrylate (Bis-GMA)--triethylene glycol dimethacrylate (TEGDMA), which formed interpenetrating polymer networks (IPN) with the preimpregnation polymer. After light-initiated polymerization of the monomer system, the rhombic test specimens (n = 6) were immersed in the simulated body fluid (SBF) with the bioactive glass for 24 h, and then the apatite nuclei were allowed to grow for 1, 3, 5 and 7 days in the SBF. The control test specimens (n = 3) were immersed in SBF without the bioactive glass. According to the scanning electron microscope (SEM), a mineral layer was formed on the surface of all the specimens, which were immersed with bioactive glass. The layer was thickened by the prolonged immersion time to a uniform layer. The Ca/P atomic ratio of the mineral varied between 1.30 and 1.54 as analyzed by the energy dispersive X-ray analysis (EDXA). The Fourier transform infrared spectroscopy (FT-IR) spectra gave signals for the mineral, which are characteristic of both bone-like apatite and orthocalciumphosphate. In conclusion, the mineral layer was formed on the surfaces of the specimens by biomimetic mineralization, the mineral being a mixture of bone-like apatite, orthocalciumphosphate and other calcium phosphates.

Characterisation of bioactive glass coatings on titanium substrates produced using a CO2 laser

Titanium and its alloys are widely used in load-bearing bioinert implants. Bioactive glasses (BAGs) form a chemical bond with bone, but they are not suitable for load-bearing applications. Creating a BAG coating on a titanium implant could combine the best properties of both materials. The results tend to be poor when conventional firing methods are applied to coat titanium with BAG. A local application of heat to melt the glass can be achieved by a CO2 laser. A new method is introduced to create BAG coatings on titanium locally in a controlled manner, with a focused CO2 laser beam. The coatings produced by this method precipitate calcium phosphate in vitro. Processing parameters (number of coated layers, laser power, and processing atmosphere) providing a firm attachment of the glass and good in vitro bioactivity were identified. XRD analysis showed no crystallisation of the glass due to processing with the laser. EDXA indicated the formation of a calcium phosphate layer, which FTIR suggested to be a hydroxyapatite. The results show CO2 laser processing to be a promising technique for the manufacture of 30-40 microm BAG coatings on titanium.

In vitro Ca-P precipitation on biodegradable thermoplastic composite of poly(ε-caprolactone-co-dl-lactide) and bioactive glass (S53P4)

Bioactive properties of composites containing poly(epsilon-caprolactone-co-DL-lactide) with molar ratio 96/4 and bioactive glass (BAG), S53P4, were tested in vitro. The glass content in the tested materials was 40, 60 or 70 wt%, and two granule size ranges (<45 and 90-315 microm) were used. The composites were analysed for their apatite-forming ability. This was determined as a function of time by the dissolution pattern of Si and Ca ions and structural changes on the specimen surfaces. Composite specimens were immersed in simulated body fluid at 37 degrees C for up to 6 months. The changes in Si and Ca concentrations of the immersion medium were determined with UV-Vis and atomic absorption spectrophotometry. The calcium phosphate precipitation and apatite formation were evaluated by scanning electron microscopy (SEM) and infra-red spectroscopy (IR) using the attenuated total reflectance (ATR) system. The SEM and SEM-EDX analysis of the depositions formed on the composite surfaces was in line with the changes in ion concentrations. The clearest results with IR were seen in the material containing 60 wt% small glass particles. The results indicate that composites containing over 40 wt% BAG granules are bioactive, and that a higher BAG surface area/volume ratio favors the apatite formation in vitro.

Local induction of calcium phosphate formation on TiO2 coatings on titanium via surface treatment with a CO2 laser

Sol-gel-derived TiO(2) coatings are known to promote bonelike hydroxyapatite formation on their surfaces in vitro and in vivo. Hydroxyapatite integrates into bone tissue. In some clinical applications, the surface of an implant is simultaneously interfaced with soft and hard tissues, so it should match the properties of both. A new method is introduced for treating the coatings locally in a controlled manner. The local densification of sol-gel-derived titania coatings on titanium substrates with a CO(2) laser was studied in terms of the in vitro calcium phosphate-inducting properties. CO(2)-laser-treated multilayer coatings were compared with furnace-fired coatings prepared with the same recipe and previously shown to be bioactive. Additionally, local areas of furnace-fired multilayer coatings (previously shown to be bioactive in vitro) were further laser-treated to achieve various properties in the same implant. Topological surface properties were examined with atomic force microscopy. The formation of hydroxyapatite was studied with Fourier transform infrared and scanning electron microscopy energy-dispersive X-ray analysis. The results show that calcium phosphate formation can be adjusted locally by laser treatment. Calcium phosphate is a bonelike hydroxyapatite. The local treatment of sol-gel-derived coatings with a CO(2) laser is a promising technique for creating implants with various properties to interface different tissues and a possible way of coating implants that do not tolerate furnace firing.

Surface properties of in vitro bioactive and non-bioactive sol-gel derived materials

The acid-base properties of several in vitro bioactive (able to form bone mineral-like calcium phosphate on their surfaces) and non-bioactive sol-gel processed oxides are studied. The amount of Lewis acid sites was calculated from the pyridine adsorption using the Langmuir adsorption model. The Henry adsorption model was used in cases where no specific affinity between the adsorbent and the probe molecule was observed. The results were used to calculate the specific amounts of acidic and basic sites on SiO2- and TiO2-based materials. The zeta potential was measured for dip-coated TiO2 films, calcium- and phosphate-doped TiO2 films and for a non-bioactive Al2O3 film. Also, the calcium phosphate formation in simulated body fluid on in vitro bioactive TiO2 film was studied with zeta potential measurements. The results showed dependence on the negative surface charge and the important role of calcium adsorption in the beginning of the calcium phosphate formation. Surface topography of the films was investigated with atomic force microscopy, including a detailed analysis of the peak heights and distribution over cross sections. It was observed that in vitro bioactivity was strongly dependent on the nanoscale dimensions. Consequently, the in vitro calcium phosphate formation seems to be due to both the chemical interactions and the surface structure.

In vitro bioactivity and structural features of mildly heat-treated sol-gel-derived silica fibers

The ability of sol-gel-derived silica fibers heat treated at a low temperature to induce formation of bone-like calcium phosphate (HCA) on their surfaces provides alternatives for the design of novel biomaterials, for example as implants used in tissue guiding or bone repairs. In this study, dry spinning was used to prepare the sol-gel fibers, which were heat-treated at 175 degrees and 250 degrees C. In addition, the differences in the surface topography (in a nanometer scale) of different fibers with respect to their in vitro bioactivity were studied. The structure of the fibers was varied using three different factors: (1) spinnable sols having varying structures and sizes of silica polymers to establish varying viscosity levels; (2) aging of green-state fibers; and (3) heat treatment of fibers. The in vitro bioactivity and solubility tests were done in simulated body fluid (SBF). To monitor surface topography and roughness of the heat-treated silica fibers, a scanning probe microscopy (SPM) with tapping mode AFM was used. Different fibers obtained clearly different properties. The fibers spun at about eta > 3.0 Pas had the best properties with respect to bioactivity, especially when they were heat-treated at 175 degrees C. It was found that surface structure in a nanometer scale was the most important factor controlling the in vitro bioactivity of heat-treated silica fibers. The correct proportions between the peaks and peak distances at the surfaces are suggested to be important with respect to in vitro bioactivity. The results indicate that peak distance distribution between 5-50 nm, especially between 5-20 nm, together with a peak height > or = 1 nm is most favorable for calcium phosphate formation.

Influence of sol and stage of spinnability on in vitro bioactivity and dissolution of sol-gel-derived SiO2 fibers

The ability of the sol-gel-derived green state silica fibers to induce the formation of bone-like calcium phosphate (HCA) on their surfaces has not been studied earlier. Bioactive silica fibers provide alternatives for the design of novel products, e.g., as implants used in tissue guiding or bone repairs. In this study, dry spinning was used to prepare the sol-gel fibers. Different fibers with different bulk structures were prepared by changing the composition and controlling the stage of spinnability. Additionally, the influence of the aging time of the fibers on the bulk structure of the samples was investigated. Furthermore, the ability to form calcium phosphate was investigated in vitro in the simulated body fluid (SBF). Transmission electron microscopy was used to illustrate the bulk structure of the green state fibers and scanning electron microscopy to illustrate the formed calcium phosphate layer on the fibers. The fibers were additionally characterized by measuring the dissolution of the silica in the SBF. In vitro bioactive silica fibers were successfully prepared. The calcium phosphate layer was formed within 1-5 days in the best case. The structural stability and the in vitro bioactivity varied with the aging time expect in one case where practically stable fibers could be prepared. The concentration of silica released in the SBF had no direct connection with the HCA formation. The silica-rich gel layer was not observed on the fibers, but the structure of the fibers was suggested to have an important role in the HCA formation.

Effect of aging time of sol on structure and in vitro calcium phosphate formation of sol-gel-derived titania films

Titanium and its alloys have been used successfully in the manufacture of orthopedic and dental implants to replace damaged bone tissue. In this study, different sol-gel-derived TiO(2) coatings were produced on titanium substrates using different aging times (5, 10, 24, or 48 h) of the sol before dipping the coatings and varying numbers (one, three, or five) of coating layers. The influence of the aging time of the sol on the structure of the titania coatings with respect to in vitro bioactivity was investigated. The in vitro bioactivity tests were done in a simulated body fluid (SBF). The sol properties were monitored using a capillary viscometer and dynamic light scattering to determine the viscosity and particle size, respectively. The topography of the films was characterized using atomic force microscopy. The various sol aging times and numbers of layers produced differences in the topography of the titania films. For the coatings with one and three layers, the aging of the sols had an influence on the height of the peaks (lower with longer aging times) although the peak distance was about the same. The number of coating layers had a stronger influence. The distribution of the peak distances became narrower with an increasing number of coating layers. The coating with three layers (top coating prepared after 24 h of sol aging) and the coatings with five layers had a similar distribution of peak distances (15-50 nm), which was favorable for calcium phosphate formation. On these substrates, calcium phosphate formation started within 3-6 days of immersion in SBF. The aging time of the titania sol and the number of coating layers were found to have a strong influence on the surface topography in the nanometer scale of the titania films. The results indicate that the topography of the outermost surface is of importance for in vitro bioactivity.

Calcium phosphate formation on porous sol-gel-derived SiO2 and CaO-P2O5-SiO2 substrates in vitro

Sol-gel-derived SiO2 and CaO-P2O5-SiO2 have been shown to be bioactive and bone bonding. In this study bioactive sol-gel-derived SiO2 and CaO-P2O5-SiO2 systems were tested for in in vitro bioactivity. The calcined ceramic monoliths were immersed in a simulated body fluid and analyzed to follow the hydroxyapatite formation on the ceramic surface. Apatite-forming ability was investigated in terms of structural changes by changing the composition and the preparation method. The role of Ca and P dopants in the substrate structure is complicated, and careful characterization is needed. The composition and structure together determine the in vitro bioactivity. The pore structure was analyzed using N2-adsorption/desorption isotherms. The results indicate that a great mesopore volume and a wide mesopore size distribution favor hydroxycarbonate apatite nucleation and a great surface area is not needed. The performed preparation process for silica in a basic environment provides a convenient way to prepare a mesoporous material.

Influence of sol and surface properties on in vitro bioactivity of sol-gel-derived TiO2 and TiO2-SiO2 films deposited by dip-coating method

Different sol-gel-derived titania and titania-silica films were prepared and their properties related to in vitro bioactivity. The films were prepared by depositing the sols on the substrate surface using a dip-coating method. The sols were monitored carefully as a function of time, using rheological techniques and dynamic light scattering. The topography of the films was characterized using atomic force microscopy, and thicknesses and refractive indexes of the films were evaluated by fitting transmittance spectra measured in a wave length region of 370-1100 nm with a spectrophotometer. The in vitro bioactivity tests were performed in simulated body fluid. Surface topography was found to be of great importance with respect to the bioactivity of the studied films.

Guanosine 5'-(gamma-[35S]thio)triphosphate autoradiography allows selective detection of histamine H3 receptor-dependent G protein activation in rat brain tissue sections

Histamine elicits its biological effects via three distinct G protein-coupled receptors, termed H1, H2, and H3. We have used guanosine 5'-(gamma-[35S]thio)triphosphate (GTPgamma[35S]) autoradiography to localize histamine receptor-dependent G protein activation in rat brain tissue sections. Initial studies revealed that in basal conditions, adenosine was present in tissue sections in sufficient concentrations to generate an adenosine A1 receptor-dependent GTPgamma[35S] signal in several brain regions. All further incubations therefore contained 8-cyclopentyl-1,3-dipropylxanthine (10 microM), a selective A1 receptor antagonist. Histamine elicited dose-dependent increments in GTPgamma[35S] binding to discrete anatomical structures, most notably the caudate putamen, cerebral cortex, and substantia nigra. The overall anatomical pattern of the histamine-evoked binding response closely reflects the known distribution of H3 binding sites and was faithfully mimicked by N(alpha)-methylhistamine, (R)-alpha-methylhistamine, and immepip, three H3-selective agonists. In all regions examined, the GTPgamma[35S] signal was reversed with thioperamide and clobenpropit, two potent H3-selective antagonists, whereas mepyramine, a specific H1 antagonist, and cimetidine, a prototypic H2 antagonist, proved ineffective. These data indicate that in rat brain tissue sections, GTPgamma[35S] autoradiography selectively detects H3 receptor-dependent signaling in response to histamine stimulation. As the existing evidence suggests that GTPgamma[35S] autoradiography preferentially reveals responses to G(i/o)-coupled receptors, our data indicate that most, if not all, central H3 binding sites represent functional receptors coupling to G(i/o), the inhibitory class of G proteins. Besides allowing more detailed studies on H3 receptor signaling within anatomically restricted regions of the CNS, GTPgamma[35S] autoradiography offers a novel approach for functional in vitro screening of H3 ligands.

Comparison of postanesthetic sequelae after clinical use of 27-gauge cutting and noncutting spinal needles

BACKGROUND AND OBJECTIVES

The tips of the bevels of thin spinal needles may be easily damaged by bony contact during puncture attempts. In this respect and also because they are less traumatic by design, noncutting, pencil-point-tip needles may be beneficial. A prospective clinical comparison of postanesthetic effects of the use of 27G Quincke-type and pencil-point spinal needles was therefore performed.

METHODS

The study included 400 spinal anesthesia patients, in 200 of whom the initial needle was a 27-gauge Quincke type, a 27-gauge pencil-point needle being used in the other 200. Altogether, 464 needles had to be used; in 30 cases the pencil-point needle was replaced by a 27- or 25-gauge Quincke-type needle. A block performance form was filled in, and the patients were interviewed personally on the first postoperative day and by means of a mailed questionnaire on the 14th day.

RESULTS

The tips of the Quincke-type needles were distorted in a blunt, bent or hooked manner in 13% of the initial and 14% of the final needles. The severity of the damage was related to the count category of bony contacts during puncture (0, 1-4, or 5 or more). The occurrence of postdural puncture headache was not, however, related either to damage of the needles or to the number of puncture attempts. Diffuse (not posture-dependent) headache occurred more often after the use of the Quincke-type needle than after use of the pencil-point needles, the tips of which remained intact in each case.

CONCLUSION

Postanesthetic sequelae, including postdural puncture headache (overall incidence 2.5%), were not related to the shape of the spinal needles or to the damage of the Quincke-type needles.

Biosynthesis of the major human red cell sialoglycoprotein, glycophorin A. O-Glycosylation

The biosynthesis of the major human red cell sialoglycoprotein, glycophorin A, was studied in the erythroleukemia cell line K562 with emphasis on O-glycosylation. The cells were pulse-chase labeled with [35S] methionine, and either directly immune precipitated with anti-glycophorin A antiserum or detergent-solubilized extracts first passed through columns containing the N-acetylgalactosamine-specific lectin from Helix pomatia or the glucose/mannose specific lectin from lentil beans. From the sugar-eluted fractions anti-glycophorin A antiserum was used to identify precursor molecules. After 5 min of labeling the first glycophorin A precursors were seen. The largest had an apparent molecular weight of 37,000, and bound to lentil lectin-Sepharose, but not to H. pomatia lectin-Sepharose. The lentil lectin-reactive glycophorin A molecules increased to Mr = 39,000 during chase and obtained sialic acids after 9 min of chase reflecting terminal N- and O-glycosylation. After 5-6 min of labeling two H. pomatia-interacting glycophorin A precursors with apparent molecular weights of 24,000 and 30,000 were obtained. These did not bind to lentil lectin-Sepharose. During chase also these molecules increased in size to Mr = 39,000. The immune precipitation of all antiglycophorin A-reactive precursor molecules was inhibited by purified red cell glycophorin A. The carboxylic ionophore, monensin, caused the accumulation of incompletely O-glycosylated glycophorin A molecules, which bound to H. pomatia lectin-Sepharose. These were degraded by treatment with endo-beta-N-acetylglucosaminidase H reflecting incomplete processing of the N-glycosidic oligosaccharide.

Kinetic model for the action of the inorganic pyrophosphatase from Streptococcus faecalis

Kinetic studies of the less active form of Streptococcus faecalis inorganic pyrophosphatase (EC 3.6.1.1), together with computational analysis, indicated that cooperativity in ligand binding contributes in a significant way to the behavior of this enzyme. The simplest model applicable to our data was a Monod-Wyman-Changeux-type, allosteric model, in which the enzyme is proposed to exist in two states, referred to as R and T states, respectively. In the absence of ligands, 94% of the enzyme was in the T state. MgPPi2- was the only substrate for the enzyme in the R form. This substrate was bound equally well by both enzyme forms, but it was hydrolyzed 5 times more efficiently by the R form than it was by the T form. Mg2PPi was bound exclusively to the T state of the enzyme, and it was hydrolyzed 25% as rapidly as MgPPi2- by the T form. Mg2PPi inhibited the hydrolysis of the more efficient substrate, MgPPi2-, by competing with MgPPi2- for the enzyme in the T form and by shifting the R----T equilibrium in favor of the T form. Mg2+ stabilized the R state, thus activating the hydrolysis of MgPPi2- and inhibiting that of Mg2PPi.

Identification of the major human sialoglycoprotein from red cells, glycophorin AM, as the receptor for Escherichia coli IH 11165 and characterization of the receptor site

The pyelonephritogenic Escherichia coli strain 1 H 11165 specifically agglutinates human erythrocytes carrying the M blood group antigen. The polymorphic forms of this antigen, M and N, are located in the NH2-terminal region of the major human red-cell sialoglycoprotein, glycophorin A. Radioactively labeled glycophorin A from M cells specifically bound to the bacteria. Purified glycophorin AM, but not glycophorin AN, efficiently inhibited for binding. Mild periodate treatment oxidized the NH2-terminal serine in glycophorin AM and this resulted in loss of binding to the bacteria. High concentrations of serine and alkali-labile oligosaccharides derived from glycophorin AM inhibited the binding, whereas the synthetic M-specific NH2-terminal pentapeptide Ser-Ser-Thr-Thr-Gly did not. Neuraminidase treatment of glycophorin AM did not destroy the binding. The most efficient inhibition of binding was observed with the N-terminal glyco-octapeptide obtained from glycophorin AM by CNBr cleavage. This peptide contains both the essential serine residue and the alkali-labile oligosaccharides, which both are recognized by the bacterium.

Characterization of Glycophorin A and band 3 from Tn polyagglutinable erythrocytes

The 2 types of erythrocytes from a person with persistent mixed-field polyagglutinability (Tn abnormality) were separated from each other by preparative cell electrophoresis. Surface labelling using the galactose oxidase/NaB3H4 technique followed by polyacrylamide gel electrophoresis showed a strong labelling in the glycophorin A region of Tn positive erythrocytes indicating exposed galactosyl N-acetyl/galactosaminyl residues. Tn positive cell membranes were labelled by the galactose oxidase/NaB3H4 technique and solubilized in non-ionic detergent. After chromatography on Helix pomatia lectin-linked Sepharose, glycophorin A was immunoprecipitated from the sugar eluate using specific antiserum. Glycophorin A from Tn negative cells and normal red blood cells did not bind to Helix pomatia lectin but to Lens culinaris lectin-Sepharose. Glycophorin A and band 3 were isolated by preparative gel electrophoresis from normal cells and the two red cell populations of the Tn individual. Pronase treatment of labelled glycophorin A followed by gel filtration revealed a more efficient proteolysis in molecules isolated from Tn positive cells. Mild alkaline treatment of galactose oxidase/NaB3H4 or periodate/NaB3H4 labelled glycophorin A liberated 3 different oligosaccharides from Tn positive cells. No significant difference was found between the oligosaccharides of band 3 protein from normal and Tn positive cells and the amounts of glycophorin A were identical in both cell types when determined by radioimmunoassay.

Cell-free synthesis and glycosylation of the major human-red-cell sialoglycoprotein, glycophorin A

The human erythroid cell line, K562, synthesizes the major red cell sialoglycoprotein, glycophorin A. We have isolated an mRNA fraction which codes for glycophorin A from K562 cells and studied the synthesis of the sialoglycoprotein in a rabbit reticulocyte cell-free system. In the absence of membranes a precursor form of glycophorin A was synthesized. This was identified using specific anti-(glycophorin A) serum. The apparent molecular weight of the carbohydrate-free precursor of glycophorin A was 19 500. This exceeds the molecular weight of the glycophorin A apoprotein by approximately 5000. In the presence of membranes from dog pancreas, the synthesized glycophorin A precursor was N-glycosylated and probably also O-glycosylated. The oligosaccharide chains remained incomplete and the glycoprotein synthesized in vitro corresponded to the glycosylated precursor of glycophorin A obtained in intact cells.

Biosynthesis of the major human red cell sialoglycoprotein, glycophorin A. A review

The human leukemia cell line K562 is erythroid and expresses the major red cell sialoglycoprotein, glycophorin A. With this cell line we have studied the biosynthesis of glycophorin A after pulse-chase labeling with [35S] methionine. Using lectin-Sepharose affinity chromatography and immune precipitation with specific anti-glycophorin A antiserum followed by polyacrylamide slab gel electrophoresis a precursor of glycophorin A was visualized. This had an apparent molecular weight of 37000 and contained an incompleted N-glycosidic oligosaccharide and unfinished O-glycosidic oligosaccharides. After chase for 10 min, the completed glycophorin A with an apparent molecular weight of 39000 was seen and it appeared at the cell surface in about 30 min. Using tunicamycin N-glycosylation was inhibited but not O-glycosylation. The absence of the N-glycosidic oligosaccharide did not affect the migration of the protein to the cell surface but the yield of glycophorin A was diminished. Translation of glycophorin A messenger-RNA was achieved in a rabbit reticulocyte cell-free system. This yielded a non-glycosylated protein with an apparent molecular weight of 19500, which exceeded that of the glycophorin A apoprotein with about 5000. This indicates the presence of a "signal sequence" in the preprotein. When the translation was performed in the presence of microsomal membranes from dog pancreas the glycophorin A apoprotein aws both N-and O-glycosylated and the apparent molecular weight (37000) of the synthesized protein was identical to that of the precursor obtained from cells.

Psychosomatic disorder: a treatment problem more difficult than neurosis? A comparative clinical study of psychosomatic and neurotic patients of the psychiatric policlinic of a general hospital

Two patient groups from the psychiatric policlinic of a general hospital were compared, the first comprised 93 patients with severe psychosomatic disorders who were not diagnosed as neurotic, and the second, 133 neurotic patients without psychosomatic symptoms. The aim of the study was to clarify anamnestic and personality differences between the groups and investigate their treatment motivation. The psychosomatic patients showed less motivation for psychiatric treatment, even though their psychiatric impairment was more severe than that of the neurotics and although the extent of their psychological symptoms was equally great. Compared with the neurotic patients, the ability to tolerate stress was poorer and the attitude toward the interview and the interviewer was more defensive in the psychosomatic patients. Compared with the neurotics, medical services were utilized to a greater extent by the psychosomatic patients, and their childhood environment and background development were characterized by somewhat more psychological disturbance.

Effect of tunicamycin on the biosynthesis of the major human red cell sialoglycoprotein, glycophorin A, in the leukemia cell line K562

The human continuous leukemia cell line K562 synthesizes and expresses on its surface the major red cell sialoglycoprotein, glycophorin A. Glycophorin A contains 1 N-glycosidic and 15 O-glycosidic oligosaccharides, which are attached to known sites on the polypeptide chain. By immune precipitation with specific anti-glycophorin A antiserum of radioactively labeled cells followed by polyacrylamide gel electrophoresis, we have been able to study its biosynthesis in considerable detail. The synthesis of the N-glycosidic oligosaccharide of glycophorin A is inhibited by the antibiotic tunicamycin, while the O-glycosidic oligosaccharides are not affected. Incomplete glycophorin A, lacking the N-glycosidic oligosaccharide, is apparently incorporated normally into the surface membrane, but the total amount of glycophorin A is decreased. Thus, N-glycosylation is not necessary for externalization of glycophorin A.

Reduction of Nitrate via a Dicarboxylate Shuttle in a Reconstituted System of Supernatant and Mitochondria from Spinach Leaves

Substantial rates of nitrate reduction could be achieved with a reconstituted system from spinach leaves containing supernatant, mitochondria, NAD(+), oxaloacetate (OAA), and an oxidizable substrate. Appropriate substrates were glycine, pyruvate, citrate, isocitrate, fumarate, or glutamate. The reduction of NO(3) (-) with any of the substrates could be inhibited by n-butyl malonate, showing that the transfer of reducing power from the mitochondria to the supernatant involved the malate exchange carrier. The addition of ADP to the reconstituted system decreased NO(3) (-) reduction and this decrease could be reversed by the addition of rotenone or antimycin A. The operation of the OAA/malate shuttle was achieved most quickly in the system when low concentrations (</=0.1 millimolar) of OAA were added. A corresponding increase in the lag time for the operation of the OAA/malate shuttle was observed when the OAA concentration was increased. Concentrations for half-maximal activity of OAA, glycine, NAD(+), and NO(3) (-) in the reconstituted system were 42 micromolar, 0.5 millimolar, 0.25 millimolar, and 26 micromolar, respectively. The transfer of reducing power from the mitochondria to the soluble phase via the OAA/malate shuttle can not only provide NADH for cytoplasmic reduction but can also sustain oxidation of tricarboxylic cycle acids and the generation of alpha-ketoglutarate independently of the respiratory electron transport chain.

The glycoprotein of measles virus. External radioactive labelling of its carbohydrate and partial characterization of the glycopeptide

Measles virus was propagated in VERO cells and purified from the culture supernatants by two successive tartrate-density-gradient centrifugations. Surface carbohydrates were labelled both in vitro and in vivo with 3H after treatment with galactose oxidase/NaB3H4 or with [3H]glucosamine. The major labelled glycoprotein in measles virions had a mol.wt. of 79 000. After labelling with periodate/NaB3H4, which would result in specific labelling of sialic acid residues, the 79 000-mol.wt. glycoprotein was very weakly labelled. This suggests that there is no or a very low amount of sialic acid in the virions. Further analysis of the glycoprotein showed that galactose is the terminal carbohydrate unit in the oligosaccharide, and the molecular weight of the glycopeptide obtained after Pronase digestion is about 3000. The oligosaccharide is attached to the polypeptide through an alkali-stable bond, indicating a N-glycosidic asparagine linkage.

Expression of the major red cell sialoglycoprotein, glycophorin A, in the human leukemic cell line K562

We have found that the human leukemic cell line K562 (Lozzio, C.B., and Lozzio, B.B. (1975) Blood 45, 321-334) synthesizes a surface membrane glycoprotein which is identical or closely similar to the major red cell sialoglycoprotein, glycophorin A. The protein can be precipitated by specific anti-glycophorin A antiserum both from surface-labeled and metabolically labeled K562 cells. Cyanogen bromide cleavage of glycophorin A from red cells and the K562 cell protein gives apparently identical fragments, and the glycopeptides and oligosaccharides obtained after Pronase and mild alkaline treatment are closely similar. An antiserum made against intact K562 cells and absorbed with normal human white blood cells precipitated surface-labeled glycophorin A from erythrocytes. The amount of glycophorin A per cell in erythrocytes and K562 cells was very similar when determined by radioimmunoassay. The K562 cells contained blood group MN activity when tested with rabbit anti-M and anti-N sera. When incubated at 37 degrees C with rabbit anti-glycophorin A F(AB)2 fragments and fluorescent sheep anti-rabbit IgG, partial redistribution of glycophorin A (patching and capping) was seen in K562 cells but not in erythrocytes.

Biosynthesis of the major human red cell sialoglycoprotein, glycophorin A, in a continuous cell line

During biosynthesis of glycophorin A in K562 cells a precursor is rapidly transferred through the endoplasmic reticulum membrane with the COOH-terminal remaining in the cytoplasm. This is glycosylated within the cell and appears at the cell surface after about 30 min. The biosynthetic pathway resembles that described for viral membrane glycoproteins.

Phospholipid composition and external labeling of aminophospholipids of human En(a--) erythrocyte membranes which lack the major sialoglycorprotein (glycophorin A)

Erythrocytes of the rare human blood group En(a--) lack the major sialoglycoprotein, glycophorin A, and the cell population heterozygous for the En(a) antigen contain half the normal amount of glycophorin A. With such cells we have studied whether glycophorin A influences the phospholipid composition and the availability of aminophospholipids to external labeling reagents. We here demonstrate that the amounts of all phospholipids are closely similar in normal and variant membranes. However, using the amino-reactive reagent trinitrobenzenesulfonate, we show that phosphatidylethanolamine is more easily labeled in intact En(a--) cells as compared to normal cells, whereas phosphatidylethanolamine shows an intermediate labeling in En(a) heterozygous cells.

Expression of the major sialoglycoprotein (glycophorin) on erythroid cells in human bone marrow

The major sialoglycoprotein of human erythrocyte membranes (glycophorin) is one of the most-studied membrane proteins. Although the structure is relatively well known, almost nothing is known about its expression in erythroid cells. To study this we raised an antiserum that reacted specifically with this protein. This was accomplished by immunization of rabbits with a preparation of glycophorin followed by absorption with En(a-) erythrocyte membranes, which lack glycophorin. By use of this antiserum and a staphylococcus protein A technique we could establish that only bone marrow cells of erythrocyte lineage express glycophorin at the cell surface. This occurs in basophilic normoblasts and later stages of erythrocyte differentiation, whereas pronormoblasts do not seem to contain glycophorin.